1. Technical Field
The present disclosure relates to an adjustable bed system, and more particularly, to an adjustable bed system with a bed frame that is adjustable in height.
2. Background of Related Art
Adjustable beds are often used in both home care, and in more formalized medical settings, e.g., hospital rooms. Adjustable beds generally include a pair of end boards, i.e., a headboard and a footboard, a bed frame that extends between the end boards to support a mattress, and a mechanism that allows the height of the bed frame to be adjusted between the end boards so that the bed frame, and thus the mattress and patient, can be raised and lowered.
Various height adjustment mechanisms are known in the art, and typically include a pair of transition boxes, or gearboxes, that are positioned on the end boards, i.e., one transition box on the footboard, and another transition box on the headboard. The transition boxes include internal gearing mechanisms, and are connected to drive screws extending vertically through the end boards such that upon actuation of the transition boxes, the drive screws rotate to either raise or lower the bed frame dependent upon the direction of rotation. One example of such an arrangement is described in U.S. Pat. No. 5,134,731 (hereinafter “the '731 patent”).
Adjustable bed systems can be either manually operated, or automatic. Manual systems utilize transition boxes that are operated via a hand crank, for example, whereas automated systems regulate operation of the transition boxes via an electric motor. In both manual and automated systems known in the art, the transition boxes are arranged on the end boards so that they face each other when the system is assembled. A drive shaft extends between, and connects, the transition boxes so that the actuation of one transition box causes corresponding actuation of the other. More specifically, since the drive shaft is connected to both the transition boxes, actuating one of the transition boxes causes rotation of the drive shaft, which thereby transmits a rotational force to the other transition box to the cause simultaneous actuation.
In adjustable bed systems such as that described in the '731 patent, the end boards are different, in that the transition boxes included on the headboard and the footboard are configured for rotation in opposite directions during use. However, such systems have led to inefficiencies during delivery and assembly. For example, on the occasion that two headboards or two footboards are inadvertently delivered, as opposed to one headboard and one footboard, the system would not function properly upon assembly, if at all. In order to remedy the predicament, the bed system would have to be disassembled, and the appropriate parts, i.e., either the missing headboard or footboard, would have to be re-delivered, resulting in not only increased operational costs, but customer dissatisfaction as well.
Systems such as those described in U.S. Pat. Nos. 6,983,495, 6,997,082, 7,302,716, and U.S. Pat. No. 7,441,289 have attempted to prevent such delivery and assembly issues via the development of identical headboards and footboards. Utilizing identical headboards and footboards reduces manufacturing costs, while also eliminating the chance for delivery of an improper end board. These systems, however, are incompatible with systems such as those described in the '731 patent.
Accordingly, the present disclosure is directed to an improved adjustable bed system, and in particular, to an improved bed frame, that is universal in the sense that it can be used with different end boards, such as those described in the '731 patent, as well as with identical end boards, such as those described in U.S. Pat. Nos. 6,983,495, 6,997,082, 7,302,716, and U.S. Pat. No. 7,441,289.


The integration of high value capacitors in integrated circuits (ICs) is limited by the fact that conventional high value capacitors take up large areas of the IC chip, thus reducing device packing density and layout efficiency. Many applications require a large number of capacitors. Often the capacitors must be incorporated as discrete off-chip components, substantially increasing the bulk of the peripheral circuitry. In view of the increasing demand for compact lightweight electronic equipment, it is desirable that the number of discrete components be reduced.
The minimum dimensions of IC capacitors are determined primarily by the relatively low dielectric constant (.di-elect cons.<10) of conventional capacitor dielectrics, e.g. SiO.sub.2 and Si.sub.3 N.sub.4. Thus, as device dimensions decrease, there is increasing interest in other dielectrics having higher dielectric constants than conventional dielectric materials.
Ferroelectric (FE) and high-epsilon (HE) dielectrics (.di-elect cons.=20 or greater) have found application in random access memory (RAM) cells since they provide for the formation of NVRAMs and DRAMs. Moreover, when used as NVRAM, ferroelectric dielectrics advantageously provide low voltage programmability, fast access times and low power consumption.
FE materials pose several integration problems. In particular, most ferroelectric materials require high temperature post-deposition oxygen anneals (600.degree. C. or above) to achieve properties desirable for storage media. However, such high anneal temperatures can be incompatible with the CMOS devices already fabricated on the wafer. Furthermore, any subsequent forming gas or hydrogen anneals (highly desirable for CMOS devices) degrade the ferroelectric material, thus requiring additional high temperature oxygen anneals late in the processing sequence which in turn are detrimental to the CMOS circuitry.
In view of the above drawbacks with prior art methods of integrating ferroelectric capacitors with CMOS structures, there is a continued need for developing a new and improved method which is capable of providing an integrated FE capacitor/CMOS structure without subjecting the CMOS structure to high temperature steps that are typically required in the prior art for ferroelectric processing.


The invention relates to the sequential storage circuits commonly referred to as xe2x80x9cflip-flopsxe2x80x9d. More particularly, the invention relates to a high-speed flip-flop that operates at very low voltage levels and can offer set and/or reset capability.
Flip-flops are sequential circuits storing either a xe2x80x9chighxe2x80x9d value (power high, or logic one) or a xe2x80x9clowxe2x80x9d value (power low, or logic zero). A flip-flop has a next value that depends on the values of one or more input signals. Conventionally, a flip-flop has data, clock, set, and/or reset input signals.
A D (data) input signal is typically clocked into the flip-flop on receipt of a given clock edge, and appears at the flip-flop output on the opposite clock edge. S (set) and R (reset) input signals are generally unclocked, meaning that when the set or reset signal becomes active (e.g., goes high), the stored value changes immediately, without waiting for the arrival of a clock edge. An active set signal forces the stored value (conventionally designated Q) high, no matter what value was previously stored. An active reset signal forces the stored value Q low, no matter what value was previously stored. In set/reset flip-flops (i.e., flip-flops having both set and reset input signals) the set and reset signals are typically restricted such that at most one of them can be active at any given time.
Flip-flops are often designed using two latches separated by passgates. FIG. 1 shows such a flip-flop, comprising a first latch including cross-coupled inverters 101 and 102, a second latch including cross-coupled inverters 103 and 104, and passgates 106, 107. The clock signal C is inverted by inverter 105 to provide inverted clock signal CB. On the falling edge of the clock signal C (or whenever signal C is low), signal CB goes high, and the data signal D passes through passgate 106 to node A, and hence into the first latch. (In the present specification, the same reference characters are used to refer to terminals, signal lines, and their corresponding signals.) The data value is inverted by inverter 101, and appears at node B. On the next rising edge of clock signal C, the inverted data from node B passes through passgate 107 to node QB (the inverted output signal), and hence into the second latch. The data is again inverted by inverter 103, and appears on the output node Q.
For the flip-flop to function properly, it must be possible to write a high value to each of nodes A and QB, and ensure that the new value overcomes a low value previously stored on the node. The new high value must pass through either passgate 106 or passgate 107, and overcome the zero value being provided by inverter 102 or inverter 104, respectively. When passing through an N-channel transistor, a high voltage value is reduced by the threshold voltage of the transistor. Therefore, if an N-channel transistor is used to implement the passgate, as shown in FIG. 1, inverters 102 and 104 are necessarily designed to be weak, and correspondingly slow. (Writing low values is not an issue, because there is no voltage degradation of a low signal through an N-channel transistor.)
At very low voltages, the high voltage value (VDD) approaches the threshold voltage of an N-channel transistor, which is generally about 0.7 volts. It is not practical to reduce this threshold voltage, because transistors with a lower threshold voltage would become unacceptably sensitive to noise. Therefore, at very low voltages, the high value passed through the passgate is not sufficient to overcome even a weak inverter (e.g., inverter 102 in FIG. 1), and therefore may not be high enough to trip inverter 101. The same limitation applies to passgate 107 and inverters 104, 103. One known solution is to implement the passgates using CMOS passgates (i.e., paired N-channel and P-channel transistors), as shown in FIG. 2.
FIG. 2A shows a well-known flip-flop similar to that of FIG. 1. The N-channel transistors forming passgates 106, 107 in FIG. 1 are replaced by CMOS passgates 206, 207, respectively. The P-channel gate terminals are driven by the inverse of the signals used to drive the N-channel gate terminals. A high value on data input D or node B is not reduced as it passes through the P-channel transistor. Therefore, the substitution of the CMOS passgates for the simple N-channel transistors ensures that new high values will be successfully latched, even at low voltages. (Of course, the high voltage level must be higher than the threshold voltage of the N-channel transistor, or no circuit containing N-channel transistors will function properly.)
A disadvantage of using CMOS passgates in flip-flops is that P-channel transistors are relatively slow compared to similarly-sized N-channel transistors. Because flip-flops are ubiquitous in nearly all integrated circuits, minimum sized gates are usually used to implement flip-flops. Passing a high logic level through a minimum sized P-channel transistor introduces a delay that can become significant.
Therefore, the flip-flop of FIG. 2A also includes another modification, which improves the operating speed of the flip-flop. CMOS passgates 208 and 209 are inserted into the latch feedback loops after inverters 202 and 204, respectively. When clock signal C goes low and inverted clock signal CB goes high, CMOS passgate 206 is turned on. In the flip-flop of FIG. 1, an incoming high data signal must then overcome a low value on node A driven by inverter 102. In the flip-flop of FIG. 2A, however, passgate 208 is turned off (because clock signal C is low), and there is no driving inverter to be overcome by the new high value. Similarly, when clock signal C goes high and inverted clock signal CB goes low, passgate 209 is turned off, and a high value on node B passes onto node QB unopposed by inverter 204. Thus, the latches in FIG. 2A change state more rapidly than the corresponding latches in FIG. 1.
FIG. 2B shows another prior art flip-flop similar to that of FIG. 2A. In the flip-flop of FIG. 2A, passgates (208, 209) are inserted between the outputs terminals of the feedback inverters (202, 204) in the latches and the nodes (A, QB) by which data is passed to the latches. These passgates provide a means for electrically isolating the feedback inverters from the-nodes when new data is provided to the latches. However, writing a low value to a latch is generally not a problem, even at low voltages. The problems are encountered only when writing a high value to the latch while overcoming a low value provided by the feedback inverter. Therefore, when writing any new value to the latch, it is only necessary to prevent the feedback inverter from driving a low value.
In the flip-flop of FIG. 2B, P-channel transistor 211 and N-channel transistor 213 form an inverter driven by node B (corresponding to inverter 202 in FIG. 2A). Inserted into the pull-down path of the inverter is an N-channel transistor 212 gated by the clock signal C. Thus, when clock signal C goes low, the new data (e.g., a high value) is written from data input terminal D to node A. Because clock signal C is low, no low signal is provided through N-channel transistor 213. Therefore, the new high value on node A is unopposed.
Similarly, P-channel transistor 221 and N-channel transistor 223 form an inverter driven by node Q (corresponding to inverter 204 in FIG. 2A). Inserted into the pull-down path of the inverter is an N-channel transistor 222 gated by inverted clock signal CB. Thus, when clock signal C goes high, the new data (e.g., a high value) is written from node B to node QB. Because inverted clock signal CB is low, no low signal is provided through N-channel transistor 223. Therefore, the new high value on node QB is unopposed.
It is possible to include feedback passgates 208 and 209 (FIG. 2A) or N-channel transistors 212 and 222 (FIG. 2B) while using N-channel transistors 106 and 107 (FIG. 1) instead of CMOS passgates 206 and 207 (FIGS. 2A and 2B) to feed the latches. Eliminating the feedback paths while writing to nodes A and QB gives improved performance compared to the flip-flop of FIG. 1. However, as described above, at very low voltages an incoming high value can be reduced below the threshold voltage of the N-channel device in the latch inverter. For example, if the power high voltage is 1.4 volts and the threshold voltage of an N-channel device is 0.7 volts, the high voltage after passing through N-channel transistor 106 or 107 is only 0.7 volts, which might or might not be sufficient to trip the latch. When processing variations are taken into account, the flip-flop becomes unreliable even at voltages higher than 1.4 volts. Therefore, the use of N-channel transistors to implement passgates 106 and 107 is not desirable for known flip-flop circuits expected to operate at low voltages.
While CMOS passgates 206 and 207 are necessary to ensure functionality at low voltages, the P-channel transistors included in the passgates still introduce undesirable delay into the data path through the flip-flop when writing high values over low values previously stored in nodes A or QB.
The issue of speed becomes more problematical when reset and/or set capability is added to the flip-flop. FIG. 3 shows a well-known flip-flop similar to that of FIG. 2A, but having reset capability. The reset signal R is inverted through inverter 310 to provide inverted reset signal RB. Inverter 201 is replaced with NAND gate 301, and the second input terminal of NAND gate 301 is driven by inverted reset signal RB. Inverter 203 is replaced with NOR gate 303, and the second input terminal of NOR gate 303 is driven by reset signal R.
Thus, when signal R goes high, signal RB goes low and node B is forced to a high value, while the output signal Q is forced to a low value. Both values are latched through the respective feedback loops.
The reset flip-flop of FIG. 3 is slower than a corresponding flip-flop without reset capability, because of the extra transistors included in NAND gate 301 and NOR gate 303. Assume that reset signal R is inactive (deasserted, or low) and signal RB is high. Whenever a high value is written from data input D to node A, node B goes low. However, node B is now pulled low through two N-channel transistors in series. (See FIG. 3A, which shows a standard CMOS NAND-gate that includes two N-channel transistors 313, 314 coupled in series and two P-channel transistors 311, 312 coupled in parallel.) Therefore, NAND gate 301 is slower than inverter 201.
Similarly, whenever a low value is written from node B to node QB, output node Q goes high (assuming the reset signal R is inactive). However, output node Q is now pulled high through two P-channel transistors in series. (See FIG. 3B, which shows a standard CMOS NOR-gate that includes two P-channel transistors 315, 316 coupled in series and two N-channel transistors 317, 318 coupled in parallel.) Therefore, NOR gate 303 is slower than inverter 203.
FIG. 4 shows a well-known flip-flop similar to that of FIG. 2A, but having set capability. The set signal S is inverted through inverter 460 to provide inverted set signal SB. Inverter 201 is replaced with NOR gate 401, and the second input terminal of NOR gate 401 is driven by set signal S. Inverter 203 is replaced with NAND gate 403, and the second input terminal of NAND gate 403 is driven by inverted set signal SB.
Thus, when signal S goes high, node B is forced to a low value, signal SB goes low, and the output signal Q is forced to a high value. Both values are latched through the respective feedback loops.
Similar to the reset flip-flop of FIG. 3, the set flip-flop of FIG. 4 is slower than a corresponding flip-flop without set capability, because of the extra transistors included in NOR gate 401 and NAND gate 403.
It is part of the nature of transistors that, all else being equal, a lower voltage means a slower operating speed. At one time, virtually all integrated circuits operated at 5 volts. However, voltage levels of integrated circuits have been rapidly decreasing, first to 3.3 volts, then 2.5 volts, and so on. Voltage levels of 1.8 volts or less are now supported by many integrated circuits.
At the same time, the operating frequencies expected from the circuits have been increasing at a rapid rate. Where once 10 megahertz was considered an acceptable clock rate, clock rates of up to 300 megahertz are now commonly specified. Integrated circuit designers are being forced to redesign many common circuits to obtain additional performance at lower voltage levels.
Therefore, it is desirable to provide high-speed flip-flops, particularly set and/or reset flip-flops, that function reliably at reduced voltage levels.
The invention provides flip-flops that are both operable at high speed and reliable at low voltage levels.
According to a first aspect of the invention, a first flip-flop includes first and second latches. When a clock signal is in a first state, a data input signal is passed to a first node of the first latch through a first passgate, and the inverted data input signal is passed to a second node of the first latch through a second passgate. When the clock signal is in a second state, a signal on the second node of the first latch is passed to a first node of the second latch through a third passgate, and the inverse of that signal is passed to a second node of the second latch through a fourth passgate.
In one embodiment, the first, second, third, and fourth passgates are N-channel transistors. CMOS passgates are used in one embodiment. However, they are not necessary in most cases, because whenever a high value is-passed to one node of a latch, a low value is passed to the other node of the latch. Therefore, the latch can safely ignore all high input values. Hence, this feature permits the flip-flops of the invention to function at very low voltages. Because writing a high value is normally much slower than writing a low value, the flip-flops of the invention also function at very high clock rates, even at low voltages.
In some embodiments, means are provided for disabling the feedback loops of each latch while data is passed to the latch. The first latch comprises first and second logic gates, with the first logic gate driving the first node and the second logic gate, and the second logic gate driving the second node and the first logic gate. The second latch also comprises first and second logic gates, with the first logic gate driving the first node and the second logic gate, and the second logic gate driving the second node and the first logic gate.
In one such embodiment, a feedback passgate is coupled between an output terminal of the first logic gate and the first node of each latch. The N-channel gate terminal of the feedback passgate in the first latch is coupled to the gate terminal of the first passgate. The P-channel gate terminal (where provided) is coupled to receive the inverse signal from the N-channel gate terminal. The N-channel gate terminal of the feedback passgate in the second latch is coupled to the gate terminal of the second passgate. The P-channel gate terminal (where provided) is coupled to receive the inverse signal from the N-channel gate terminal.
In another such embodiment, an N-channel transistor is inserted into the pull-down path of the first logic gate of each latch. Thus, when the N-channel transistor is xe2x80x9coffxe2x80x9d, the logic gate does not pull the first node of the latch low, and a high value is easily written to the latch.
A second aspect of the invention enables the use of cross-coupled inverters, rather than NAND gates and NOR gates, to implement set, reset, and set/reset flip-flops. Because inverters are faster than similarly-sized NAND and NOR gates, this features also increases the speed at which the flip-flop can operate.
In a flip-flop according to this aspect of the invention, a first latch comprises first and second inverters, with the first inverter driving the first node and the second inverter, and the second inverter driving the second node and the first inverter. The second latch also comprises first and second inverters, with the first inverter driving the first node and the second inverter, and the second inverter driving the second node and the first inverter. For each latch, at least one pull-up and at least one pull-down are coupled directly to the nodes of the latch. The pull-ups and pull-downs are controlled by set and/or reset signals applied to the flip-flop.
In a reset flip-flop according to one embodiment of the invention, a first pull-down is coupled to the first node of the first latch, with the gate terminal of the first pull-down being driven by a reset signal. A first pull-up is coupled to the first node of the second latch, with the gate terminal of the first pull-up being driven by an inverted reset signal. Optionally, a second pull-up is coupled to the second node of the first latch, with the gate terminal of the second pull-up being driven by the inverted reset signal, and a second pull-down is coupled to the second node of the second latch, with the gate terminal of the second pull-down being driven by the reset signal.
In a set flip-flop according to another embodiment of the invention, a third pull-up is coupled to the first node of the first latch, with the gate terminal of the third pull-up being driven by an inverted set signal. A third pull-down is coupled to the first node of the second latch, with the gate terminal of the third pull-down being driven by the set signal. Optionally, a fourth pull-down is coupled to the second node of the first latch, with the gate terminal of the fourth pull-down being driven by the set signal, and a fourth pull-up is coupled to the second node of the second latch, with the gate terminal of the fourth pull-up being driven by the inverted set signal.
In a set/reset flip-flop according to yet another embodiment of the invention, all of the above-mentioned first and second pull-ups and pull-downs are included. In another embodiment, all of the first, second, third, and fourth pullups and pull-downs are included. In another embodiment, only the third and fourth pull-ups and pull-downs are included. For all of the set/reset flip-flops of the invention, the set and reset signals are preferably restricted such that at most one of them can be active at any given time.
According to a third aspect of the invention, both the first and second aspects are applied. In other words, when an input signal is applied to one terminal of each latch, an inverted input signal is applied to the other terminal of the same latch. In addition, set and/or reset capability is provided by coupling at least one pull-up and at least one pull-down directly to the nodes of the latch. Thus, set and/or reset flip-flops are provided having the advantages of both high speed and the ability to function properly at very low power levels.


1. Technical Field of the Invention
The invention is in the field of kinetic anti-projectile interceptor vehicles.
2. Description of the Related Art
Interceptors have been proposed to intercept and disable or destroy space-based or space-entering projectiles, for example ballistic projectiles such as intercontinental ballistic missiles. Such projectiles travel at very high rates of speed and have short travel times, making interception of them a difficult problem, one in which there is room for further improvements.


Non-aqueous electrolyte batteries that use a non-aqueous electrolyte such as lithium-ion secondary batteries provide a high energy density at a high voltage and have a reduced size and a reduced weight, and thus are widely used primarily as power sources for information terminals such as personal computers and cellular phones. Common examples of the non-aqueous electrolyte used in the non-aqueous electrolyte batteries include a solution obtained by dissolving a supporting salt such as LiPF6 in an aprotic organic solvent such as an ester compound and an ether compound. Because the aprotic organic solvent is flammable, however, the battery may be ignited when the liquid leaks from the battery or the battery generates an abnormal amount of heat, which is disadvantageous in terms of safety.
The possibility of expanded use of the non-aqueous electrolyte batteries as power sources for large devices such as power sources for power storage and power sources for electric vehicles has recently been studied. Therefore, it has been an important issue to enhance the safety of the non-aqueous electrolyte batteries with a view to increasing the size of the batteries. For example, Japanese Unexamined Patent Application Publication No. 2000-173619 (Patent Document 1) discloses a technology for suppressing ignition or rupture of the non-aqueous electrolyte batteries by covering the surface of a negative electrode with a phosphazene monomer which is a flame retardant material, as a technology for enhancing the safety of the batteries.


1. Field of the Invention
The present invention is directed to isolated switching voltage converters and more particularly to primary side sensing of the output voltage on the secondary side of a switching voltage converter.
2. Description of the Related Art
Switching voltage converters (also referred to herein as switching voltage regulators) are used to provide, e.g., regulated DC output voltage from an unregulated AC input. Typical consumer products involving such switching regulators include cell phone chargers, laptop or printer power supplies (so-called “bricks”), and embedded PC power supplies.
FIG. 1 illustrates a switching regulator 100 having a flyback topology commonly used in power supplies with output power less than 200 W. The illustrated topology is suitable for discontinuous current mode (DCM) operation in which the transformer core is fully demagnetized in each cycle. Another mode of operation is continuous current mode (CCM).
The switching regulator 100 includes high voltage isolation between the DC output (secondary side) and the AC mains input (primary side). The isolation is required for safety/regulatory reasons and may also be required for functional reasons. The power is transferred from the primary side to the secondary side using a transformer 102 meeting isolation requirements and primary side high voltage switch 104.
The switching regulator shown in FIG. 1 operates as follows for DCM operation. When the power MOSFET switch 104 turns ON (TON phase) according to the gate control signal supplied by the controller integrated circuit 106, the current through primary winding 105 ramps up with a slope of Vin/Lp and the energy stored in the transformer core at the end of the TON cycle is proportional to 0.5×Lp×Ippeak2, where Lp is the transformer primary winding inductance and Ippeak is the primary winding peak current. The output current Is is zero during the TON phase and the voltage Vs is negative referenced to the secondary side ground, Vs=−Ns*Vin, where Ns is the transformer secondary/primary turn ratio.
When switch 104 turns OFF (TOFF phase), the primary inductor current Ip becomes zero and secondary current Is ramps down from the value Ispeak=Ippeak/Ns to zero, with a slope of approximately ˜(Vout+Vdout)/Ls. When Is>0 and Q1 is OFF, the output voltage is reflected according to the transformer turn ratio back to the primary side and is usually called primary flyback voltage: Vfly_p˜(Vout+Vdout)/Ns, where Vout is the output voltage, Vdout is a voltage drop across the output diode 107 and Ns is defined as above. Once the secondary winding current Is reaches zero, both transformer windings become open (provided that loading on auxiliary winding can be neglected) and flyback voltage converts to damped ringing waveform fueled by residual energy in the Lp and Cd resonant circuit, where Cd is the total equivalent capacitance at the drain of Q1.
Accurate regulation of the output voltage requires feedback proportional to output voltage. The feedback controls the duty cycle of switch 104 in order to keep the output voltage constant over changing load and input voltage. The feedback path needs to cross the isolation barrier between the primary and secondary. A common feedback solution uses an opto-coupler 108 as shown in FIG. 1.
The use of an opto-coupler for feedback has costs such as additional components as well as PCB area space. An opto-coupler feedback approach typically requires additional passive and active components like resistors, capacitors and a shunt regulator. The shunt regulator 109 can be alternatively replaced by Zener diode when lower quality output voltage regulation accuracy can be tolerated.
There have been suggestions to replace the opto-coupler and regulate the output voltage by sensing the flyback voltage at either the primary winding or at an auxiliary winding (sometimes referred to as a bias winding). Such approaches are usually denoted as regulation using magnetic flux sensing or primary side sensing. However prior art primary side sensing approaches have had problems with accurately determining the flyback voltage. Accordingly, improved primary side sensing is desirable.


There is increasing demand for portable computing devices, such as a smartphone, adapted to perform a wide array of functions. The technological sophistication of these devices has increased to meet this demand, such that many portable computing devices are effectively mobile computers completed with an integral display. Because of their mobility and sophistication, said devices are particularly susceptible to damage. A number of cases have been developed to protect such devices from fall damage, water exposure, or like hazards.
Many aspects of modern life have become dependent upon the use of portable computing or smartphone devices. For example, in addition to voice communication, many people have come to rely upon their smartphone for basic functions, such as e-mail and navigation. Numerous software applications have also been developed to monitor or diagnose certain health conditions using the basic functions of said devices, such as a camera and a microphone. Although useful, the specialized capabilities of many such applications are inherently limited by the capabilities of the smartphone itself.
Therefore, continuing need exists for an electronic device holder that is adapted to protect an electronic device. It would be further desirable to provide a holder that can enhance the capabilities of said device.


Field
The present disclosure relates generally to a method and apparatus for detecting license plate information from an image of a license plate and more specifically, detecting license plate information from an optical image, captured by a mobile apparatus, that includes a license plate image and several other object images.
Background
In recent years, collecting still images of license plates has become a common tool used by authorities to catch the drivers of vehicles that may engage in improper or unlawful activity. For example, law enforcement authorities have set up stationary traffic cameras to photograph the license plates of vehicles that may be traveling above a posted speed limit at a specific portion of a road or vehicles that drive through red lights. Toll booth operators also commonly use such stationary cameras to photograph vehicles that may pass through a toll booth without paying the required toll. However, all of these scenarios have a common thread. The camera must be manually installed and configured such that it will always photograph the vehicle's license plate at a specific angle and when the vehicle is in a specific location. Any unexpected modifications, such as a shift in angle or location of the camera would render the camera incapable of properly collecting license plate images.
Additionally, camera equipped mobile apparatuses (e.g., smartphones) have become increasingly prevalent in today's society. Mobile apparatuses are frequently used to capture optical images and for many users serve as a replacement for a simple digital camera because the camera equipped mobile apparatus provides an image that is often as good as those produced by simple digital cameras and can easily be transmitted (shared) over a network.
The positioning constraints put on the traffic cameras make it difficult to take images of license plates from different angles and distances and still achieve an accurate reading. Therefore, it would be difficult to scale the same license plate image capture process performed by law enforcement authorities to mobile apparatuses. In other words, it is difficult to derive license plate information from an image of a license plate taken from a mobile image capture apparatus at a variety of angles, distances, ambient conditions, mobile apparatus motion, and when other object images are also in the image, which hinders a user's ability to easily gather valuable information about specific vehicles when engaging in a number of different vehicle related activities such as buying and selling vehicles, insuring vehicles, and obtaining financing for vehicles.


1. Field of the Invention
The present invention relates to a plate-like filter element, a filter unit formed by stacking up a plurality of the filter elements or a filter device installed therein, the filter unit being used to mainly trap or remove particulates contained in an exhaust gas discharged from a diesel engine which is mainly used for various vehicles, vessels or industrial appliances.
An exhaust gas discharged from a diesel engine contains particulates including carbon particles as a main component at a fairly high content, which causes air pollution.
2. Description of the Related Art
Various devices have been proposed to trap or remove the particulates contained in the exhaust gas by using a filter means.
For instance, Japanese Unexamined Patent Publication No. 124417/1981 discloses a filter unit 20 made of ceramics as shown in FIG. 9. The filter unit 20 shows an outer configuration of a rectangular prism as a whole and comprises a plurality of (eight in FIG. 9) rectangular plate-like bodies 21, 22 placed in parallel to each other, vertical end ribs 23, 25 and a number of intermediate ribs 24, 26.
All the plate-like bodies 21, 22, ribs 23, 25 and intermediate ribs 24, 26 or at least the plate-like bodies 22 are made of gas-permeable porous thin ceramic wall having a filtering function. The plate-like bodies 21 constitute the upper and lower walls of the filter unit 20, and the plate-like bodies 22 constitute the intermediate walls. Between adjacent plate-like bodies 21, 22 and between adjacent plate-like bodies 22, 22, the end ribs 23 and the intermediate ribs 24 are respectively interposed so as to be in parallel to one side of the plate-like body 21. The upper edges of the ribs 23, 24 are jointed to the upper plate like body 21 or 22, and the lower edges of the ribs 23, 24 are jointed to the lower plate-like body 22 or 21, whereby a plurality of particulate-containing gas passages 27 with both ends opened are formed. In one side of the plate-like body 22, the ribs 23, 24 are formed, and in the other side of the same plate-like body 22, the ribs 25, 26 are formed extending in the direction perpendicular to the ribs 23 24. The ribs 25, 26 are formed substantially in the same manner as the ribs 23, 24 and differ in that they are formed in the direction perpendicular to that of the ribs 23, 24. Thus, a plurality of particulate-containing gas passages 27 and clean gas passages 28 with both ends opened are alternately formed, where the direction of passages of the former is perpendicular to the passages of the later.
In the filter unit, both ends of the particulate-containing gas passages 27 are opened, but the openings at their one side of the passages 27 are directly or indirectly closed, and an exhaust gas from a diesel engine is introduced from the openings of the other side of the filter unit 20. Or, alternatively, the exhaust gas from the diesel engine can be introduced from the openings opened at the both ends simultaneously. The plate-like bodies 22 function as a filter wall, and particulates are trapped on the surface of the plate-like bodies 22 at the side of the particulate-containing gas passages 27, whereby a clean gas without particulates passes through the plate like bodies 22 and then to the outside of the filter unit via the clean gas passages 28. The trapped carbonaceous particulates in the exhaust gas are removed by burning when the plate-like bodies 22 are heated at appropriate time intervals. Thus, the filter unit 20 is refreshed.
In the prior art technique as described above, the carbon particulates collected are burnt off by heating the plate-like bodies 22 having a filtering function to the ignition temperature of the particulates to thereby remove them. However, the plate-like bodies 22 are exposed repeatedly to a high temperature when the particles are periodically burnt off. Accordingly, sintering of the plate-like bodies is further accelerated, whereby a distribution of pore size originally formed changes to thereby increase a pressure loss during the particulates trapping operation. This causes difficulty in maintaining a stable performance of the filter unit. Further, a damage by fusion of the plate-like bodies 22 may take place when they are subjected to a high temperature at the time of burning off the particulates. When such damage occurs, it is no more possible to trap the particulates.
The particulates of exhaust gas from the diesel engine contains not only carbon but also an unnegligible amount of non-combustible components (for instance, 1%-5% by weight to the total amount of the particulates), and these non-combustible components are also trapped by the filter unit. Furthermore, the exhaust gas contains components such as SOx and NOx, which corrode materials constituting conduit elements to produce non-combustible solid components which deposit on the filter unit. These non-combustible solid components can not be removed by burning and accumulate in the filter unit to cause clogging, whereby properties of the filter unit are deteriorated.
Japanese Unexamined Patent Publication No. 225721/1984 discloses a dust removing apparatus for a hot dust-containing gas. The dust removing apparatus comprises a plurality of vertical filter tubes having both ends opened. A dust-containing gas is introduced from the upper portion of the filter tubes. Dusts hindered by the filter tube walls from passing therethrough are moved downwardly in the filter tubes and are collected in a dust hopper provided below the filter tubes, while a clean gas obtained by passing through the filter tube walls is discharged from the side walls of the filter unit. It is understood that the dust removing apparatus disclosed in this document is suitable for treating a large flow rate of gas containing noncombustible combustible dusts discharged from an apparatus such as a converter in an iron plant. However, the document does not suggest application of the apparatus to the treatment of an exhaust gas from a diesel engine.
Supposing this kind of system for a compact filter unit, it is easy to manufacture the simple shaped filter tubes, but there is such a problem that an assembling process requiring much labor and time is needed in order to fix a number of thin filter tubes to support plates with spaces among the tubes and it is not easy to manufacture a filter unit having a large capacity.
The applicant of this application proposed (in Japanese Patent Application No. 232360/1987) a filter device for an exhaust gas from the diesel engine as shown in FIG. 10 in order to solve the above-mentioned problem.
A typical example of such device will be described.
A filter unit 33 having a rectangular solid form which is substantially the same as the filter unit shown in FIG. 9 is used.
The filter unit is secured in a casing 31 having openings at upper and lower parts and a side port by interposing sealing members 32 as shown in FIG. 10. In passages and respectively have one end closed and the 34 which vertically pass through the filter unit 33 (as shwon by solid line arrow marks in FIG. 10) and clean gas passages 35 (as shown by broken line arrow mark in FIG. 10) which cross the particulate-containing gas passages and respectively have one end closed and the other end opened, and each passages are defined by plate-like bodies 22 made of a gas-permeable porous material.
An inlet duct 37 is formed at the upper part of the casing 31 to introduce an exhaust gas from the diesel engine. An outlet conduit 38 is connected to the casing 31 at a side where the clean gas passages 35 are open. The outlet conduit 38 is provided with a throat portion 39 having a reduced diameter part, and the portions contiguous to the upstream and the downstream of the throat portion are gently expanded. A nozzle 40 for ejecting a pressurized gas, which is used for back washing, is provided near the downstream side of the throat portion 39 so as to open toward the upstream side.
A particulate receiving section 41 is provided at the lower part of the casing 31. The particulate receiving section 41 is provided with a tray 42, a filter plate 43 with an electric resistance type heater 46, an ash component removing port 44 with a removable cover plate 47 (it is usually closed), and a gas duct 45.
A part of the bottom of the tray 42 is perforated and the filter plate 43 is fitted to that part so that the tray 42 and the filter plate 43 surround as a whole all the lower open ends of the particulate-containing gas passages 34 of the filter unit 33. The ash component removing port 44 is open at the bottom of the tray 42, and the gas duct 45 is placed below the filter plate 43. The filter plate 43 is made of a gas-permeable porous material. The ratio of a filtering area of the filter plate 43 to that of the filter unit 33 is such that about 20% or lower portion, especially about 0.5%-5% portion, therefore, small portion of the total exhaust gas introduced from the inlet duct 37 passes through the filter plate 43, and the remaining portion of the exhaust gas passes through the plate-like bodies 22 of the filter unit 33 to be flown to the outlet conduit 38.
The exhaust gas from the diesel engine is introduced from the inlet duct 37 via the upper open ends into the particulate-containing gas passages 34 of the filter unit 33. The most part of the exhaust gas passes through the plate-like bodies 22, the clean gas passage 35 and is flown to the outlet conduit 38. However, particulates in the exhaust gas are trapped by the plate-like bodies 22 and deposit on the inner surfaces of the particulate-containing gas passages 34. A part of the particulates flow to the particulate receiving section 41 together with a part of the exhaust gas through the lower open end of the particulate-containing gas passages 34. The part of the exhaust gas passes through the filter plate 43 to the gas duct 45. However, the particulates in the part of the exhaust gas can not pass through the filter plate 43 and deposit on the inner surface of the filter plate 43.
After a continuation of the particulate trapping operation for an appropriate period, a short time back washing operation is carried out. In the back washing operation, a pressurized gas, especially pressurized air is ejected from the nozzle 40 for a short time such as about 0.1 sec-1 sec. The ejected gas induces the gas around the nozzle 40, and the gas of several times as much as the original ejected gas is flown in a pulse form to the clean gas passages 35. The pulse gas flow is flown to the particulate-containing gas passages 34 through the plate-like bodies 22. Then, the particulates accumulated on the inner surface of the particulate-containing gas passages 34 are peeled off. A part of the particulates drifts in the particulate-containing gas passages 34, however, the most part drops into the particulate receiving section 41. In the particulate receiving section 41, a stream of gas is produced to pass through the filter plate 43, and being carried with the gas flow, the most part of particulates deposit and accumulate on the inner surface of the filter plate 43.
Thus, the particulates trapped on the inner surfaces of the particulate-containing gas passages 34 during the particulate trapping operation are moved onto the inner surface of the filter plate 43 by the back washing operation to thereby refresh the filtering function of the filter unit 33. The particulates on the filter plate 43 are burnt and removed by heating the electric resistance type heater 46.
After a relatively long term use of the apparatus, there occurs accumulation of non-combustible residue or ash. In this case, the cover plate 47 is opened to remove the residue or ash. Alternatively, they may be forcibly removed by a suitable scraping means.
However, the above-mentioned filter device had a disadvantage as follows. When the back washing gas was introduced in a pulse form into the clean gas passages 35 repeatedly, a high gas pressure head such as about 0.3-0.4 kg/cm.sup.2 is instantaneously applied to the inside of the clean gas passages 35. Each application of the pressure head induces a stress to the plate-like bodies 22 which separate the clean gas passages 35 from the particulate-containing gas passages 34 in the filter unit 33 and finally damages the plate-like bodies 22.
Further, the conventional filter unit as shown in FIG. 9 had a complicated structure which requires much labor and long manufacturing time and the yield rate is low.


The present invention relates to mowers comprising bottom-driven discs, more particularly those where the discs are driven by means of bevel couplings. In this type of mower the bevel couplings are housed either in a single housing extending beneath all the discs and containing a bath of lubricant, or in housings where the lubricant is in danger of escaping when the transmission shaft extending through each disc housing is withdrawn therefrom.
All these machines possess one or more of the following drawbacks:
Lengthy and delicate assembly and dismantlement both for the manufacturer and especially for the user,
Necessity of adjustment of the bevel coupling each time the transmission member passing through the disc housing must be re-fitted after repair,
Risk of oil losses, especially during repairs,
Risk of penetration of dirt into the bevel couplings and their bearings,
Risk of incorrect oil level; it is known that even a slight upward or downward variation of oil level involves grave consequences in view of the high rotation speed of the bevel couplings driving the discs,
Risk of poor lubrication of the end bevel couplings when the cutter bar is working in an inclined position, for example along a slope, and risk of deterioration of a large number of transmission members in the case of an accident to any one of them.
The purpose of the present invention is to remedy all these drawbacks.


The present invention relates to a 4-acyloxyquinoline derivative and an insecticide containing it as an effective ingredient.
A variety of compounds having insecticidal or acaricidal activities have hitherto been developed. However, it is desired to develop a new insecticide having an excellent activity because of the problem such as the recent increase of insecticidal resistance.


The present invention relates to a group of new compounds of the general formula I:
Nu-O-Fa
wherein O represents an oxygen, Nu is a nucleoside or nucleoside analogue, and Fa is an acyl group of a mono-unsaturated C18 or C20 fatty acid. The invention also concerns anti-viral pharmaceutical and veterinary compositions comprising a compound of formula I alone or in combination with a pharmaceutically acceptable carrier. A further part of this invention is a method for the treatment of a human or animal patient suffering from a viral infection and for reducing the infectious load by administering a compound of formula I.
A large number of serious diseases, such as AIDS, hepatitis B, herpes and gynecological cancer, as a late result of papilloma warts, are caused by viral infections.
Viruses are small infectious agents which are incapable of independent replication and thus are dependent on a host cell to replicate. The genetic material of the virus is either RNA or DNA.
When infecting an organism, the virus attaches to a specific host cell. The virus penetrates the cytoplasmic membrane after attachment and the viral genome is released from the virus particle. The viral genome is usually transported to the cell nucleus where new viral genomes are replicated. New viral protein is synthesized in the cytoplasm and new particles are formed either close to the cytoplasmic or nuclear membrane.
Some viruses have genomic material which is directly (DNA virus) or indirectly (Reverse transcription of RNA, retrovirus) incorporated in the host cell genomes.
Extracellular viruses are neutralized by circulating antibodies and the cellular immune apparatus may attack and remove infected cells. Viruses within the infected cells escape immune surveillance if viral antigens are not exposed on the surface of the cells.
The immune attack on infected organs contributes to disease by a mechanism commonly called virus induced immuno-pathology.
The mechanisms underlying some of the more important viral diseases differ.
When suffering from a HIV infection, the patient""s T helper cells are invaded and destroyed. This leads to a immunodeficiency condition, which makes the patient very succeptible even to infections which normally are conquered by the immune system without any harmful effects for the patient.
The Hepatitis B virus invades the liver cells, and the patient may become very ill when the immune system tries to rid the body of these infected cells. If the infection is not conquered by the immune system at an early stage, the result will be chronic hepatitis. The patient will thus be infectious throughout his life. For a group of patients the chronic hepatitis will develop into cirrhosis or cancer of the liver.
In herpes simplex infections, the virus enters the epidermal cells originally. The herpes simplex virus travels up to a nerve center where it lies latent to break out at intervals. Although not life threatening in most cases, a herpes infection is painful and the patient will be infectious every time an outbreak occurs.
In the papilloma virus, notably in the genital tract of women, the viral genome is located in the nucleus of epithelial cells, but not integrated in the cell chromosomes. This is a persistent condition and with some tumor promoting strains an integration finally occurs leading to a malignant development. The viral genome in this case has a decisive initiating effect in the process leading to cancer.
If the immune system manages to rid the body of the virus at an early stage, this leads to a life long immunity. On the other hand, if the virus is too aggressive and avoids the immune apparatus, no immunity is achieved and a continuous infectious state is the result.
As a result of the different mechanisms, the therapeutic strategy would be different for these conditions.
The ultimate goal in the treatment of HIV/AIDS would be to free the patient from the infectious virus. This seems to be remote at the present stage. However, much can be obtained by improving the general condition of the patient. A reduction of the virus load would increase the length of the symptom free period and reduce the infectiousness, which is of utmost importance in regard to the epidemiological situation. All currently used anti-viral agents have toxic side effects, which presently makes a sufficiently aggressive treatment impossible.
It is assumed that there are between 250 and 300 million carriers of hepatitis B world wide. It is known that a great number of these are going to develop hepatomas or liver insufficiencies due to the infections. Promising results in the treatment of the carrier state have been obtained in recent years by induction of an immune response with interferon. Therapies reducing the virus load are important in this regimen as efficient treatment of acute hepatitis B would reduce the number developing into a carrier state. The recently identified hepatitis C virus causes a very great number of cases with hepatitis whereof a large number develop into carriers. Preliminary studies seem to indicate that the carrier state may be broken by similar therapeutic regimens as for hepatitis B. Herpes simplex 1 and 2 frequently infect humans causing a carrier state with recurrencies of local infections. Generalized infections including encephalitis are rare but a catastrophy for the patient. There is a great individual variation in the frequency of local infections. For those patients who are affected either genitally or facially this constitutes a serious health problem physically, mentally and socially. None of the therapeutic regimens developed so far cures the latent infections of cells in the central nervous system. The therapeutic goal is thus to minimize the clinical manifestations of recurrencies both as to symptoms and duration.
The prevalence of genital papilloma virus infections has increased dramatically during the 1980s. It is now established that some genotypes are oncogenic, that is they initiate changes in the cell which after a latency period develop into cancer. Papilloma virus of the genital tract give long standing infections. The factors causing malignant transformation of the lesions are not well understood, but the immune system is assumed to be of importance. It is thought that the lesions showing progression during the months and years are those giving rise to cancer. The genital papillomas called condylomas are at present treated by physical means such as surgical removal, necrotizing means, fluid nitrogen or the like. Genital warts are at the onset benign tumors with altered enzyme patterns affecting among other things the metabolism of nucleoside analogues. Nucleoside prodrugs affect the episomal proliferation of papilloma virus thereby inducing regression of the warts.
Prophylactic vaccination has been very successful in acute infections such as polio, measles, mumps etc., but no effective vaccination has been developed for many of the other serious viral infections.
Even though there have been intensive efforts to produce effective anti-viral chemotherapeutica during the last decades, no satisfactory medical treatment can be offered for most viral diseases today. The efforts have been especially great since the appearance of the HIV and related viral infections, which are spreading throughout the world at an alarming rate, yet the effects obtained with agents such as azidothymidine (AZT) and acyclovir (ACV) in AIDS and herpes can only be characterized as partially successful. These most promising anti-viral agents are thus derivatives of naturally occurring nucleosides, which have been modified either in the base or sugar moiety. They have, however, not had the therapeutic potential hoped for, as they bring forward serious side-effects in some patients or show little or no effect in others. Further, treatment with these agents is extremely expensive. For these reasons only patients suffering from the very serious viral infections such as AIDS receive such treatment. Patients suffering from the less serious, but also very painful viral infections are often left without any treatment to let the infection take its own course.
The untreated patient carries a great infectious load and constitutes a risk to his fellow human beings. If he is treated with an anti-viral agent, the aim is to reduce the infectious load so as to enable the body""s immune system to conquer the infection. A further aim is to reduce the contagiousness and thus the number of new patients and carriers.
Thus the need for compounds having a better therapeutic index is obvious.
The need is especially great in chronic or recurrent viral infections with a dangerous acute phase or long term ill effects on health or well being, such as AIDS, hepatitis B and C, infections of the herpes group and papilloma viral infections. Similarily, there is also a need for anti-viral agents usable in the treatment of animals suffering from viral diseases.
In order to improve the effect, there have been developed derivatives of the nuclosides which are either modified in the base or sugar moiety. Especially fatty acid esters of the nucleosides or of analogues of nucleosides have been developed, in order to improve the lipophility and achieve a better membrane passage.
Thus there are known from EP 56265 (Lxc3x6bering et al.) esters of arabino-furanosyl-thymine (Ara T) with saturated acids having 1-17 C-atoms.
From PCT/WO90/00555 (Hostetler et al.) there are known lipid derivatives linked, epecially through a phosphate group, to the 5xe2x80x2-position of the pentose group of a nucleoside. The purpose of this derivatization was to make the nucleosides more lipophilic so that they could be included into liposomes, which are preferentially taken up by macrophages and monocytes, cells which are found to harbor the HIV virus. It is stated that a targetting effect is thereby achieved.
From EP 393920 there are known unsaturated, preferably polyunsaturated, C16 or higher fatty acid esters or amides of nucleoside or nucleoside analogues. It is stated that the fatty acid portion of these molecules preferably are made up of poly-unsaturated fatty acids, such as xcex3-linolenic or linoleic acid.
It has now surprisingly been found that a selected group of fatty acid, esters of anti-viral nucleosides or nucleoside analogues, wherein the fatty acid is a mono-unsaturated C18 or C20 acid gives a much improved effect. Also the compounds according to the present invention seem to be relatively nontoxic as judged by growth experiments with young mice and also have a low cytotoxicity according to observations made in tissue culture experiments.
Although it is known that both nucleosides and nucleoside analogues, by themselves, and also some unsaturated fatty acids, by themselves, exhibit anti-viral effects, the magnitude of the effects achieved with the compounds according to this invention indicates that this is not an additive, but rather a synergistic activity which is special for the compounds of formula I.
The mechanism behind these effects is at present not known, but they are of an order of magnitude better than the closest related compounds of the prior art. Thus it is not considered likely that they arise only due to a membrane effect or targetting effect.
Further it is also clear, as will appear from the biological examples included herein, that effects are achieved with these compounds in systems where no effects may be achieved with the mother nucleoside compound.
The compounds of this invention can be characterized by the general formula I:
Nu-O-Fa
wherein O is an oxygen, Nu is a nucleoside or nucleoside analogue and Fa is an acyl group of a mono-unsaturated C18 or C20 fatty acid.
Nucleosides are molecules comprising a heterocyclic base, such as cytosine, uracil, adenine or guanine, linked to a ribose unit. In nucleoside analogues, either the base or the ribose unit has been modified. For example, the ribose unit may be replaced by another sugar unit or by a noncyclic chain.
The fatty acid is esterified with a hydroxyl group in the 5-position of the sugar moiety of the nucleoside or with a hydroxyl group on the non-cyclic group of the nucleoside analogue.
The nucleoside or nucleoside analogues which may be chosen as Nu in the compounds of formula I may preferably be represented by the formula II:
Sxe2x80x94Bxe2x80x83xe2x80x83(II)
wherein S is either a mono-saccharide-derivative selected from: 1-xcex2-D-arabinofuranose or 2,3-di-deoxy-3-azido-1-xcex2-D-ribofuranose, or selected from the group of 2-hydroxy-ethoxy-methyl, 4-hydroxy-3-(hydroxymethyl)-butyl, 2-hydroxy-1-(hydroxy-methyl)-ethoxy-methyl or 2,3-di-hydroxy-propoxy; and B is a nitrogen base selected from adenine, guanine, cytosine, uracil, thymine or a thymine derivative of the following formula:
Wherein X is deuterium or fluorine.
Examples of these nucleosides or nucleoside analogues are:
Examples of the group R in different nucleoside analogues appear below:
There exist several systems for denomination of the position of double bonds in fatty acids. In the present application the xcfx89-system is used, wherein the position of the double bond in the unsaturated fatty acids is counted from the terminal methyl group. Eicosenic acid (C20:1 xcfx89-9), for example, has 20 carbon atoms in the chain, and the double bond is found between carbon atom 9 and 10 counting from the end of the chain.
The fatty acids which are reacted with the nucleosides or nucleoside analogues to form the esters according to this invention with the pronounced activity are the xcfx89-9 C18 or C20 monounsaturated fatty acids. Further, even though the effect observed differs somewhat between acids of the same chain length when the double bond is in cis or trans configuration, both show a strong activity. Also the position of the double bond is of importance, as it appears that especially the esters with a C18 or C20 fatty acid having the unsaturation in xcfx89-9 position will have the surprisingly elevated activity.
The C18 or C20 xcfx89-9 fatty acids, which when bound to the nucleosides give the surprisingly elevated effect, are the following: oleic acid (C18:1, xcfx89-9, cis), elaidic acid (C18:1, xcfx89-9, trans) eicosenic acid, (c20:1, xcfx89-9, cis) and (C20:1, xcfx89-9, trans)
Preferred representatives of the compounds according to this invention are listed below.: Ara A-oleic acid, Ara A-elaidic acid, Ara A-eicosenic acid, cis, Ara A-eicosenic acid, trans, Ara T-oleic acid, Ara T-elaidic acid, Ara T-eicosenic acid, cis, Ara T-eicosenic acid, trans, ACV-oleic acid, ACV-elaidic acid, ACV-eicosenic acid, cis, ACV-eicosenic acid, trans, AZT-oleic acid, AZT-elaidic acid, AZT-eicosenic acid, cis, AZT-eicosenic acid, trans. Their formulas will appear from FIG. 4.
The compounds according to this invention exhibit anti-viral effects, and the present invention thus includes pharmaceutical or veterinary compositions comprising at least one compound of formula I alone or in combination with a pharmaceutically acceptable carrier or excipient. In the remainder of the text and in the claims, a pharmaceutical composition will be used for compositions usable in the treatment of both human and animal patients.
Further, it appears that certain of the monounsaturated fatty acid nucleosides or nucleoside analogues will be especially suitable for the treatment of certain viral infections. Thus it appears that the fatty acid derivatives of AZT are especially useful for the treatment of AIDS.
Similarly, it appears that the fatty acid derivatives of Ara T and Ara A are especially suitable for the treatment of hepatitis B. It appears also that the Ara T esters will be efficient in agents suitable for treatment of papilloma viral infections.
Further, it appears that the fatty acid esters according to this invention of ACV are especially suitable for the treatment of herpes infections.
As mentioned, the production of the necessary immune response in order to conquer a viral infection, such as hepatitis, can be induced in some cases by the co-administration of interferon.
Depending on which viral infection is to be treated and at what stage the infection is, or if the patient is a human being or an animal, both a systemic and a local administration of the compounds can take place.
For local administration, the compounds can be formulated as known in the art for administration to the skin or mucosa in any suitable form.
When administered topically the compounds of formula I may be formulated as an ointment, cream, gel, tincture, spray, lotion or the like containing the compounds of formula I in admixture with inert, solid or liquid carriers which are usual in topical preparations. It is especially suitable to use a formulation which protects the active ingredient against oxidation or degradation.
The pharmaceutical preparations comprising the compounds of formula I may also be administered systemically, either enterally or parenterally.
When administered enterally, the compounds of formula I may be formulated e.g. as soft or hard gelatine capsules, tablets, granules, grains or powders, dragees, syrups, suspensions or solutions.
When administered parenterally, preparations of the compounds of formula I as injection or infusion solutions, suspensions or emulsions are suitable.
The preparations can contain inert or pharmacodynamically active additives. Tablets or granulates e.g. can contain a series of binding agents, filler materials, carrier substances or diluents. Liquid preparations may be present, for example, in the form of a sterile solution. Capsules can contain a filler material or thickening agent in addition to the active ingredient. Furthermore, flavor-improving additives as well as the substances usually used as preserving, stabilizing, moisture-retaining and emulsifying agents, salts for varying the osmotic pressure, buffers and other additives may also be present.
The dosages in which the preparations according to this invention are administered will vary according to the mode of use and the route of use, as well as to the requirements of the patient. In general a daily dosage for a systemic therapy for an adult average patient will be about 0.1-100 mg/kg body weight/day, preferably 1-20 mg/kg/day. For topical administration, the suitable ointment can contain from 0.1-10% by weight of the pharmaceutical formulation, especially 0.5-5% by weight.
If desired, the pharmaceutical preparation of the compound of formula I can contain an antioxidant, e.g. tocopherol, N-methyl-tocopheramine, butylated hydroxyanisole, ascorbic acid or butylated hydroxytoluene.
The invention further discloses a method for the treatment of viral infections, which comprises administering at least one compound of formula I to a human or animal patient in need of such treatment.
Further, the invention also comprises a method for the treatment of a patient in need of such treatment with a combination of a compound of formula I and an interferon.


This invention relates to curing of phenolic novolac resins at high temperatures. More particularly, this invention relates to the use of (lower) alkoxylated melamine-formaldehyde resins and (lower) alkoxylated benzoguanamine-formaldehyde resins as curing or hardening agents for novolacs at high temperature. The curing agents of this invention are also simply referred to herein as triazine hardeners.
In, refractory applications, there is a need for a binder comprising a phenolic novolac and a curing agent wherein the binder remains uncured until high temperatures are attained. In the binders of this invention at least 50% of the cure and preferably at least 80% of the cure is accomplished above 392.degree. F. (200.degree. C.). This minimizes hardening and solidification of the binder in heated equipment and provides improved flow properties and prolonged workability for the binder.
There is also a need for such binder compositions which can be delivered to hot surfaces under pressure wherein the compositions further contain a particulate refractory and water wherein the hardener is not leached out from intimate contact with the other ingredients of the composition. This prevents or minimizes stratification on drying and curing of the composition.
Pitch as well as phenolic resins are used as binders for aggregates to prepare compositions for refractory tap hole application for blast furnaces. Tap hole mix users need a combination of early green strength and stability at 150.degree. F. (65.degree. C.) to 250.degree. F. (121.degree. C.) for up to several hours. Novolac with hexamethylenetetramine (hexa) has been used in such compositions. Also, hexa has been used as a hardener for novolac in the manufacture of electrodes. However, novolac/hexa binders lead to early cure whereas novolac without hexa or other hardener do not cure. Resoles are also unsatisfactory in such compositions because they cure at too low a temperature.
Melamine resins have also been mentioned as curing agents for novolacs or as thermosetting resins along with resoles, etc. in refractory compositions. However, the melamine resins used in this invention have advantageous properties in their use.
It is known that novolacs containing acids or thermally produced latent acids strongly catalyze the cure of melamine resins. However, the acid lowers the normal curing temperature of the novolac.
Apparatus and procedures exist for the robotic spraying of refractory material in a slurry of about 20% water for maintenance and repair of heated refractory surfaces. Illustrative of such a system is the TUNCAST Tundish Spray System of Foseco Inc.


In gas turbine engines, the operational clearances between static engine structures and the tips of rotating blades impact performance aspects such as the thermodynamic efficiency and fuel burn of the engine. It is desirable to reduce the operational clearances, while at the same time avoiding contact between the rotating blade tips and the static structure. The performance improvement value of as little as a tenth of a millimeter in clearance reduction is significant. In response to thermal excursions, the lengths of the blade tips typically vary at a different rate than that at which the static structures expand or contract. Variation in position or concentricity leads to a need for greater clearances and suboptimal performance. For example, without excess clearance, the blade tips may contact the static structure negatively impacting engine performance. Excess clearance between the blade tips and the static structure may also reduce engine performance. When engine designs result in higher temperatures such as to achieve greater efficiency, maintaining optimal clearance without excess cooling air becomes more challenging.
Accordingly, it is desirable to provide systems that effectively retain and control the position of the static structure relative to the blade tips. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.


The invention relates to the field of cutlery and it has as an object a relief of a blade of a cutting tool, in particular of a knife.
There are known profiles which are arranged on the blades in order to level their cutting loss due to use and wear, which profiles are constituted by microtoothing which is composed of a plurality of incurved surfaces having parallel generatrixes, called microbevels, defining with one of the side faces of the blade a plurality of respective microcutters.
The inconvenience of the conventional microtoothing, formed by a plurality of short microbevels arranged along the blade, is based on the fact that the resulting short microcutters form a toothing which induces a shredding of the material to be cut up, where the tool therefore practically no longer cuts and, finally, being of a delicate use since the material, in particular meat, is soft.
In order to remedy this inconvenience, the efforts of the innovators has been directed to the refining of a microtoothing composed of short microbevels and of long microbevels, succeeding each other alternatingly, wherein the first shred the matter while the second cut the matter. One could in particular refer to the document EP-A-0220362 which describes a tool blade comprising such a microtoothing. In addition, the blade carries along its other face a bevel for reinforcing its cutting characteristic.
The result obtained is satisfying with regard to the improvement of the performance of the tool for cutting the matter but retains nevertheless another general drawback of microtoothed tools, namely to make their utilization delicate based on the presence of the microbevels which induce a tendency of the blade to incline itself by turning its blade edge toward the microbevelled face.
In addition, tools are known which carry a microtoothing composed of a plurality of short microcutters, successively formed by the short microbevels arranged respectively oppositely on each one of the side faces of the blade, in order to confer to the tool a natural stability during the time of its utilization.
The use of this type of tool, which is of relatively ancient origin, has been rapidly abandoned because of its high manufacturing cost, brought about by the difficulty of placing oppositely the microbevels arranged on the one and the other face of the blade, resulting in an unsatisfactory cut based on the cutter absence on the blade.


Surface measurement systems are used in a variety of applications to generate three dimensional surface data of objects. Such systems are employed at various stages in the fabrication and assembly of complex objects across a variety of industries to ensure that the shape and size of the objects meet strict manufacturing tolerances.
Interferometric surface measurement systems have been developed which permit measurements of the surface of an object without physical contact. Coherent optical sources are used to generate a fringe pattern on the surface of the object and a camera acquires images of the fringes on the surface for analysis. In some systems, a diffraction grating is positioned in the path of a laser beam to generate multiple coherent laser beams at various angles to the original beam path. A focusing objective and spatial filter are used to isolate the desired diffracted beam pair. One or more additional diffraction gratings are utilized to project at least one additional set of fringes onto the object surface. This multiplexing of different gratings into the beam path poses many challenges. Moving different gratings into the beam path and shifting each grating to implement phase shifts generally requires multiple mechanical components that add weight, size, complexity and cost to the system. The frequent movement of components affects the stability and therefore the accuracy of the measurement data. Moreover, measuring the displacement of a diffraction grating during the phase shift process with sufficient precision and accuracy can require expensive measurement components such as capacitance gauges.
Other system components can limit the applications for the system. For example, the focusing objective and spatial filter are used for multiple gratings and, therefore, their optical parameters are not optimal for the individual gratings. Moreover, the depth of field of the camera can limit the maximum spatial frequency of the projected fringe pattern, thereby limiting the measurement resolution.
Noise sources also typically limit the measurement data. When laser light is scattered from a surface, a high-contrast, granular speckle pattern is typically observed. Speckle results in part from the roughness of the object surface. In particular, the microscopic roughness of the surface contributes randomly phased contributions of the scattered laser light. These contributions interfere with one another to produce complex intensity variations across the surface of the object as viewed from a distance. Speckle introduces fine-scale intensity fluctuations (i.e., intensity noise) in the observed fringe pattern on the object surface. Shot noise contributions from the individual detectors in the camera can further limit the accuracy of measurement data.


The present invention relates to a semiconductor device, particularly to a multi-chips module (MCM) type semiconductor device adapted to be mounted on a board and to be electrically connected to the board.
JP-A-11-220077 discloses that a coefficient of thermal expansion and so forth is adjusted to restrain a crack of a semiconductor element and/or an under-fill in a flip-chip type semiconductor device. JP-A-2000-40775 discloses a shape of an oblique surface of the under-fill is adjusted to restrain the crack of the semiconductor element.


1. Technical Field
The present disclosure relates to data networks providing access to data storage in general and, in particular, to optimization of power consumption by network nodes operating as data storage.
2. Description of the Related Art
Media, such as audio recordings and films, can nowadays be effectively archived in digital format, and it is used by private persons and by large organizations. In the case of large organizations the number of records (i.e., individual audio or video recordings) can be very large. Additionally, the size of digitized media files, especially video files converted to high quality digital format, is large, and in consequence archives of media files require large memory space. The digitized media can be stored on various media, e.g., CD-ROM, DVD, Blue Ray, HD DVD, hard disks, magnetic tapes, and others.
For large organizations using hard disks for storing media data is very useful as it does not require any manual or mechanical operations to be performed in order to access the files stored on that drive, and as a result it can be accessed from a remote location (e.g., a branch of this organization) via a network (e.g., intranet or Internet).
The problem faced by some organizations is that the number of media files is growing very fast, and the old files cannot be simply deleted because, for example, they are classified as part of national heritage and as such must be archived indefinitely. This results in a constantly expanding archive. The problem of available memory space can be solved by connecting additional hard disk drives to the existing ones.
While the solution with a plurality of hard disk drives may provide adequate space for storing the media files, it also requires a substantial amount of electricity to run. Power consumption of a storage system comprised of 10,000 hard disks, each consuming 25 W is 250 kW. By reducing power consumption of such a system, significant financial benefits can be gained, and additionally its impact on the environment will be reduced.


1. Field of the Invention
The present invention generally relates to gift cards, and, more particularly, to systems and methods for gift card linking.
2. Description of the Related Art
Gift cards are very popular, and are often among the most requested type of gift. Gift cards provide advantages for everyone involved in the gift-giving process. For example, the gift card giver does not have to spend time determining the gift that the gift receiver wants, needs, or has, but can instead give a gift card to one of the gift receiver's preferred merchants. The gift card receiver can select what he or she wants, and does not have to worry about returns or exchanges. The merchants often see an increase in sales, as the gift card receivers often spend more than the amount of the gift card.


An automobile has an openable/closable mechanism including a box and a lid such as a glove box. A damper is provided to the edge of a box the glove box. When a lid of the glove box is closed, the damper functions to suppress the collision shook between the lid and the box with the elastic force by abutting on the lid.
The damping part described in Patent Document 1 includes a casing having a bottomed cylindrical shape, a retainer having a bottomed cylindrical shape and housed in the casing, and a spring abutting on the bottom of the casing and the bottom of the retainer to bias the retainer in a direction that the retainer protrudes out from an opening portion of the casing. A retaining protrusion provided on a lateral face of the retainer is engaged into an engagement window provided on a lateral face of the casing, and thereby retaining the retainer the biasing force of the spring.


The present invention relates generally to the field of tactile feedback technology, and more particularly to creating a visual representation of tactile feedback.
Haptic technology, or haptics, is a tactile feedback technology that recreates the sense of touch by applying forces, vibrations, or motions to a user through actuators (e.g., motors responsible for movement) incorporated in a computing device. Haptics manipulate the actuator using defined waveforms to produce a range of effects which may be perceived uniquely by an individual touching the computing device. Initially, haptics were only capable of providing strong feedback with a limited range of sensations to an entire device or providing limited localization of haptic feedback to a specific position (e.g., display instead of the body of the device) with an expanded effects, such as frequency range, response time, and intensity. As the technology continues to evolve, haptics currently incorporated in computing devices now provide the means to deliver both touch-coordinate specific responses and customizable haptic effects (e.g., virtual keyboard scrolling list) to the user.
When sensing physical interaction between a user and a computing device is necessary, haptic computing devices incorporate tactile sensors that measure information arising from a physical interaction with the environment. One of the most common implementations of tactile sensors are touchscreen devices, such as those utilized in mobile devices and computing. The touchscreen device allows a user to interact directly with what is displayed (e.g., images, icons, virtual keyboards, applications, etc.) by touching the screen with a specialized stylus and/or one or more fingers rather than utilizing an intermediate device, such as a computer mouse or a touchpad. The mechanical stimulation provided by the haptic feedback may then be utilized to assist in the creation of virtual objects in a computer simulation (e.g., developed model representing characteristics, behaviors, and functions of a physical or abstract system over time). The continued exchanges between the user and computer simulation via the touchscreen may then provide additional feedback (e.g., changes and updates to images, text responses, change in displayed information, etc.), which allows for confirmation of actions taken by a user and for additional interactions to occur based on received responses.
Digital images created and displayed by a computing device include metadata. Metadata provides information regarding the data content of the actual digital image. For example, digital images may include metadata that describes how large the picture is, the color depth, the image resolution, when the image was created, and other relevant data. In addition to the aforementioned metadata, additional metadata (e.g., GPS coordinates, compression ratios, software, etc.) and object tags (e.g., non-hierarchical keyword or term assigned to a digital image describing an item) may be changed and assigned to the digital image by a user and through image processing software which includes incorporating tactile effects. For example, a user or image processing software may identify objects and the boundaries associated with the object within a digital image. Once the boundaries of an object are defined, additional tactile effects may then be added to the metadata (e.g., tactile metadata), enhancing the viewing experience of future users.


Modern communications systems permit callers and callees, who are often separated by great distances, to freely dialogue with one another. However, when a caller initiates a call (or session) to a callee, very little information about the callee may be available to the caller prior to establishing a session. Similarly, when a callee receives a call from a caller, very little information about the caller may be available to the callee until a session has been established. In some instances, additional information about a caller or callee may facilitate dialogue between the two parties. To date, very little is available to provide such information in a communication system. A need, therefore, exists in the industry to address this deficiency.


Mobile communication devices such as smartphones, tablet computers, wearable devices, etc. are widely used by consumers for many things other than voice communications. Specifically, these devices are designed so that consumers can install various applications, which may perform many different tasks. For example, various applications may be used for things such as shopping lists, text messaging, social network communications and sharing, research, weather reporting, news, and so forth.
Applications such as this often rely on interactions with remote servers or data stores, and may further rely on wireless data connectivity to communicate with such remote servers or data stores. For example, a weather application may communicate with a remote server in order to obtain weather information. Similarly, a list application may store lists on a remote server or database so that the lists can also be accessed on multiple devices.
In many situations, data connectivity is available to mobile devices through cellular communications networks, which are provided by cellular communication providers. Cellular communication providers maintain large infrastructures for providing wireless data communications for mobile devices. A cellular services infrastructure includes geographically distributed base stations as well as centralized communication services. In addition, many cellular communication providers also provide various consumer applications for installation and use on the mobile devices of their customers. For example, a cellular communication provider may provide an application that allows customers to manage their cellular service accounts. Customers may also obtain, install, and use many other applications, many of which may rely on the availability of cellular data communications.


Polysaccharides constitute the bulk of the plant cell walls and have been traditionally classified into three categories: cellulose, hemicellulose, and pectin. Fry, (1988) The growing plant cell wall: Chemical and metabolic analysis, New York: Longman Scientific & Technical. Whereas cellulose is made at the plasma membrane and directly laid down into the cell wall, hemicellulosic and pectic polymers are first made in the Golgi apparatus and then exported to the cell wall by exocytosis. Ray, et al., (1976), Ber. Deutsch. Bot. Ges. Bd. 89:121-146. The variety of chemical linkages in the pectic and hemicellulosic polysaccharides indicates that there must be tens of polysaccharide synthases in the Golgi apparatus. Darvill et al., (1980) The primary cell walls of flowering plants. In The Plant Cell (N. E. Tolbert, ed.), Vol. 1 in Series: The biochemistry of plants: A comprehensive treatise, eds. P. K. Stumpf and E. E. Conn (New York: Academic Press), pp. 91-162.
Even though sugar and polysaccharide compositions of the plant cell walls have been well characterized, very limited progress has been made toward identification of the enzymes involved in polysaccharides formation, the reason being their labile nature and recalcitrance to solubilization by available detergents. Sporadic claims for the identification of cellulose synthase from plant sources were made over the years. Callaghan, and Benziman, (1984) Nature 311:165-167; Okuda, et al., (1993) Plant Physiol. 101:1131-1142. However, these claims were met with skepticism. Callaghan and Benziman, (1985), Nature 314:383-384; Delmer, et al., (1993), Plant Physiol. 103:307-308. It was only relatively recently that a putative gene for plant cellulose synthase (CesA) was cloned from the developing cotton fibers based on homology to the bacterial gene. Pear, et al., Proc. Natl. Acad. Sci. USA 93:12637-12642; Saxena, et al., (1990), Plant Molecular Biology 15:673-684; see also, WO 9818949; see also, Arioli, et al., (1998). Molecular analysis of cellulose biosynthesis in Arabidopsis. Science Washington D.C. Jan. 279, 717-720. A number of genes for cellulose synthase family were later isolated from other plant species based on sequence homology to the cotton gene (Richmond and Somerville (2000), The cellulose synthase superfamily, Plant Physiology 124:495-498.)
Cellulose, by virtue of its ability to form semicrystalline microfibrils, has a very high tensile strength which approaches that of some metals. Niklas, (1992), Plant Biomechanics: An engineering approach to plant form and function, The University of Chicago Press, p. 607. Bending strength of the culm of normal and brittle-culm mutants of barley has been found to be directly correlated with the concentration of cellulose in the cell wall. Kokubo, et al., (1989), Plant Physiology 91:876-882; Kokubo, et al., (1991) Plant Physiology 97:509-514.
Although stalk composition contributes to numerous quality factors important in maize breeding, little is known in the art about the impact of cellulose levels on such agronomically important traits as stalk lodging, silage digestibility, or downstream processing. The present invention provides these and other advantages.


Projectors are used for presentations in school classrooms, meeting rooms and the like, as well as in private home theatres. As a light source, such projectors use a high-pressure discharge lamp that is nearly a point light source. In particular, high-pressure mercury lamps are used.
A high-pressure mercury lamp encloses a halogen substance along with mercury, and includes an arc tube in which a pair of tungsten electrodes are disposed in mutual opposition. Light is radiated by the emission of an arc discharge between the electrodes. In a high-pressure mercury lamp, the halogen cycle is used to constrain the blackening effect produced during lighting. The blackening effect refers to the tungsten making up the electrodes evaporating and coming to adhere to the inside of the arc tube. The tungsten so evaporated is made to return to the electrodes through the halogen cycle, and comes to accumulate. As such, given a protrusion formed by such accumulation on the tip portions of both electrodes, the luminescent spots of the arc discharge spanning the inter-electrode distance are the two protrusions.
In recent years, demand for ever-increasing longevity in the high-pressure mercury lamp serving as the light source has grown alongside projector use. As a response to such demand, an effective method has been discovered in preserving the stability of the arc discharge by maintaining an appropriate shape in the protrusions formed on the tip portions of the pair of electrodes.
One proposed method for forming and maintaining an appropriate shape for said protrusions involves a high-pressure discharge lamp lighting device configured to switch between two or more frequencies for the AC current supplied to the high-pressure mercury lamp (see, for example, Patent Literature 1). Patent Literature 1 describes causing growth in the protrusions by applying suitable AC current in at least one frequency, and causing reduction in the protrusions by applying suitable AC current in other frequencies. The shape of the protrusions is thus preserved by repeatedly alternating between the frequencies to cause growth and reduction.


It is known that organic and polymeric materials with large delocalized .pi.-electron systems can exhibit nonlinear optical response, which in many cases is a much larger response than by inorganic substrates.
In addition, the properties of organic and polymeric materials can be varied to optimize other desirable properties, such as mechanical and thermoxidative stability and high laser damage threshold, with preservation of the electronic interactions responsible for nonlinear optical effects.
Thin films of organic or polymeric materials with large second order nonlinearities in combination with silicon-based electronic circuitry have potential as systems for laser modulation and deflection, information control in optical circuitry, and the like.
Other novel processes occurring through third order nonlinearity such as degenerate four-wave mixing, whereby real-time processing of optical fields occurs, have potential utility in such diverse fields as optical communications and integrated circuit fabrication.
Of particular importance for conjugated organic systems is the fact that the origin of the nonlinear effects is the polarization of the .pi.-electron cloud as opposed to displacement or rearrangement of nuclear coordinates found in inorganic materials.
Nonlinear optical properties of organic and polymeric materials was the subject of a symposium sponsored by the ACS division of Polymer Chemistry at the 18th meeting of the American Chemical Society, September 1982. Papers presented at the meeting are published in ACS Symposium Series 233, American Chemical Society, Washington, D.C. 1983.
The above recited publications are incorporated herein by reference.
Of more specific interest with respect to the present invention embodiments is prior art relating to polymers with comb-like side chains. Eur. Polym. J., 18, 651(1982) describes liquid crystalline polymers of the smectic and nematic types with cyanobiphenyl groups in the side chain: ##STR2## where R is hydrogen or methyl, n is an integer of 2-11, and X is an oxy, alkylene or carbonyloxy divalent radical.
SPIE Vol. 682, pages 56-64, Molecular and Polymeric Optoelectronic Materials: Fundamentals and Applications (presented at Aug. 21-22, 1986 meeting) describes liquid crystalline polymeric systems which are copolymers of a mesogenic monomer and a nonlinear optically responsive monomer.
A disadvantage of liquid crystalline polymers which exhibit mesogenic side chain nonlinear optical response is an observed light scattering effect when the polymer is in the form of a solid phase optical medium, e.g., the polymer medium exhibits more than about 20 percent scattering of transmitted incident light. The light scattering is due to deviations from ideal molecular order which accommodate defects that are not optically clear.
There is continuing interest in the theory and practice of polymers which are characterized by comb-like side chain structures which can be oriented in an applied external field.
There is also an increasing research effort to develop new nonlinear optical organic systems for prospective novel phenomena and devices adapted for laser frequency conversion, information control in optical circuitry, light valves and optical switches. The potential utility of organic materials with large second order and third order nonlinearities for very high frequency application contrasts with bandwidth limitations of conventional inorganic electrooptic materials.
Accordingly, it is an object of this invention to provide novel polymers with comb-like side chains.
It is another object of this invention to provide acrylic copolymers having side chains which exhibit nonlinear optical response.
It is a further object of this invention to provide optical light switch and light modulator devices with a transparent polymeric nonlinear optical component comprising an isotropic acrylic copolymer.
Other objects and advantages of the present invention shall become apparent from the accompanying description and examples.