The present invention relates to a manufacturing method of a semiconductor device and more particularly to a backside film which is formed by growing a film on both surface sides of a semiconductor substrate.
When a thin film is formed on a semiconductor substrate, the film is grown on either both of the obverse surface and the reverse surface of the semiconductor substrate (double-sided growth) or only the obverse surface thereof (single-sided growth), depending on the method of growing a film, the flow of the steps in the manufacturing method, the apparatus used therein and so forth.
For example, in the case that a polycrystalline silicon film to fabricate a gate electrode or the like, an insulating film to form a sidewall film, an interlayer insulating film or such is to be formed, as the film is generally grown by the LP-CVD (Low Pressure-Chemical Vapour Deposition) method, the deposition of the film proceeds not only on the obverse surface side of the semiconductor substrate but also on the reverse surface side thereof.
The backside film of this sort is, subsequently, removed by the following reasons.
Firstly, when another film is to be formed by the CVD method following formation of the foregoing film, the semiconductor substrate may not be able to be fixed onto a CVD apparatus satisfactorily, unless the backside film is removed. Secondly, in transporting the semiconductor substrate in the steps of a manufacturing method, the presence of any backside film may prevent the semiconductor substrate from attaching onto a transportation vehicle sufficiently. Thirdly, in the step of performing photolithography, if any backside film is left behind, focus at exposure may shift.
For the above reasons, when a thin film is grown on both surface sides of a semiconductor substrate in the conventional manufacturing method, the step of removing the backside film is performed before proceeding other steps. The semiconductor substrate is formed into a prescribed thickness by grinding from the reverse surface, after all other steps are completed.
However, in the methods of manufacturing a semiconductor device wherein a thin film is formed through double-sided growth and its backside film part is then removed, there are occasions in which waste matter and dust are generated in the steps subsequent to the step of the removal.
For instance, as shown in FIG. 4(a), after element isolation regions 502 are formed on a semiconductor substrate 501, a gate oxide film 503b is grown. Following that, as shown in FIG. 4(b), a polycrystalline silicon film 503 to fabricate gate electrodes is formed into a thickness of 200 nm or so. As the LP-CVD method is generally employed for the forming method, the polycrystalline silicon film 503 is grown on both of the obverse surface side and the reverse surface side of the semiconductor substrate 501. Consequently, etching is performed to remove a part of the polycrystalline silicon film 503 formed on the reverse surface side of the semiconductor substrate 501 and thereby a structure shown in FIG. 4(c) is obtained. In this instance, a portion of the polycrystalline silicon film lying on the edge section on the obverse surface side of the semiconductor substrate 501 may be, in part, removed therewith. The gate oxide film 503b on the reverse surface side can be also removed hereat, if circumstances require.
After that, as shown in FIG. 4(d), a silicide film 504 with a thickness of 200 nm or so is formed only on the obverse surface side of the semiconductor substrate, using the sputtering method.
The polycrystalline silicon film 503 and the silicide film 504 fabricated as described above are then etched and worked into gate electrodes, as shown in FIG. 4(c). In some cases, however, that etching conducted to form gate electrodes leaves a residue 505 behind, as shown in FIG. 4(e), which causes generation of waste matter and dust.
Further, after the gate electrodes are formed, for the purpose of forming sidewall films on the sidewalls of the gate electrodes, an insulating film 506 with a thickness of 250 nm or so is formed through double-sided growth by the LP-CVD method (FIG. 5(f)). Next, as shown in FIG. 5(g), the insulating film 506 lying on the side of the obverse surface is etched and sidewall films 506 are formed on the lateral faces of the gate electrodes 503a. After that, as shown in FIG. 5(h), the insulating film 506 formed on the side of the reverse surface of the semiconductor substrate is removed by means of etching, but, also on this occasion, a residue 507 may remain, as shown in FIG. 5(g), causing generation of waste matter and dust.
If waste matter and dust are generated, as described above, in the steps of manufacturing a semiconductor device, a sufficient yield may not be able to be attained, and besides an additional steps of etching to remove waste matter and dust may become necessary, which lowers productivity.
Further, because the step of removing the backside film is performed independently from the step of grinding the reverse surface of the semiconductor substrate finally, the manufacturing method may become unduly complicated and, in some cases, even satisfactory productivity cannot be achieved.
Further, in Japanese Patent Application Laid-open No. 266192/1997, there is disclosed a method wherein a film is formed on the obverse surface as well as the reverse surface of a wafer, and thereafter the foregoing film lying on the obverse surface of the foregoing wafer is subjected to etching, while the foregoing film lying on the reverse surface of the wafer is made to remain. Further, in the method described in that publication, as the steps of the method proceed, layers of polysilicon and other materials become overlaid on the reverse surface of the semiconductor substrate, and it is described therein that these layers are peeled off together after the step of the final heating treatment, namely, a high temperature treatment at 800xc2x0 C.-850xc2x0 C., which may exert thermal stress is completed.
Nevertheless, the main concern in that publication is thermal stress produced in the semiconductor substrate by the heat treatment when the semiconductor substrate has different numbers of films formed on the obverse surface and the reverse surface. Accordingly, this problem of thermal stress is solved by growing films equally on both of the obverse surface and the reverse surface and making qualities and thicknesses of these films on both surfaces identical, and nothing is mentioned therein to reduce the amount of waste matter and dust.
Moreover, although the films formed on the reverse surface of the semiconductor device are peeled off together after the heating steps are completed, grinding is not described to apply to the reverse surface of the semiconductor device. In effect, in a method of the publication, even after the backside films are peeled off, another film may be grown by a method without heat application, which may lead to formation of a backside film.
As set forth above, waste matter and dust brought about by removing the backside film which is formed through double-sided growth have not been hitherto regarded as a serious problem. Under such circumstances, the present inventors recognized waste matter and dust of this sort can be one of prime factors to lower yield and productivity in semiconductor device fabrication. Accordingly, an object of the present invention is to suppress generation of waste matter and attain satisfactory yield and productivity. Further, another object of the present invention is to achieve an improvement in productivity by performing the step of removing the backside film, concurrently with the step of grinding the reverse surface of the semiconductor substrate.
In light of the above problems, the present invention provides a method of manufacturing a semiconductor device, which comprises the steps of:
forming a first film on both of an obverse surface side and a reverse surface side of a semiconductor substrate; and
removing, by means of grinding, said first film formed on the reverse surface side of said semiconductor substrate as well as a part of said semiconductor substrate in depth from the reverse surface.
More specifically, the present invention provides a method of manufacturing a semiconductor device; which comprises the steps of
forming a polycrystalline silicon film into a thickness of not less than 50 nm but not greater than 150 nm on both of an obverse surface side and a reverse surface side of a semiconductor substrate;
forming, only on the obverse surface side of said semiconductor substrate, a silicide film into a thickness of not less than 50 nm but not greater than 200 nm over said polycrystalline silicon film;
working said polycrystalline silicon film and said silicide film into shape and thereby forming a gate electrode;
forming, on both of the obverse surface side and the reverse surface side of said semiconductor substrate, an insulating film for sidewall formation into a thickness of not less than 50 nm but not greater than 200 nm to cover said gate electrode;
etching said insulating film for sidewall formation which is formed on the obverse surface side of said semiconductor substrate and thereby forming a sidewall film on a lateral face of said gate electrode;
forming, only on the obverse surface side of said semiconductor substrate, an interlayer insulating film into a thickness of not less than 500 nm but not greater than 1.5 xcexcm to cover said gate electrode; and
removing, by means of grinding, said polycrystalline silicon film and said insulating film for sidewall formation, both of which are formed on the reverse surface side of said semiconductor substrate, as well as a part of said semiconductor substrate in depth from the reverse surface.
In the above manufacturing methods, any backside film formed through double-sided growth is not removed until fabrication of the obverse surface of the semiconductor substrate is completed, and, after completing the obverse surface fabrication, in the step of grinding the reverse surface of the semiconductor substrate, the backside films are also all removed by means of grinding. Further, as the method of growing a film, a method of single-sided growth, in other words, a method in which no film is allowed to grow on the reverse surface side of the semiconductor substrate, should be employed therein ,as long as circumstances permit. As a result, generation of waste matter can be well suppressed and satisfactory yield can be attained. Further, because it is unnecessary to perform any additional etching to remove waste matter, the manufacturing method becomes simplified and satisfactory productivity, provided. Furthermore, since the removal of the backside films is carried out along with final grinding of the reverse surface of the semiconductor substrate, the manufacturing method becomes simplified and productivity, enhanced.
In this manufacturing method of the present invention, any backside film formed through double-sided growth is not removed until fabrication of the obverse surface of the semiconductor substrate is completed, and, after completing the obverse surface fabrication, in the step of grinding the reverse surface, the backside films are removed together. As a result, even if the manufacturing method comprises the step of double-sided growth of a thin film, it can be avoided that a part of the film remains as waste matter on the wafer edge section while the obverse surface is fabricated, which facilitates to attain excellent yield and productivity.


1. Field of the Invention
The present invention related to a system and a method capable of emulating existing tape drive systems and to also remotely archive and retrieve data files via encrypted validation communication protocol.
2. Prior Art
It is necessary to store and backup data for many mainframe computer installations primarily for the purpose of safekeeping critical information to be used in the event of an unexpected loss of the primary copy. The backups are often remotely stored offsite of the mainframe installation.
At one time, ten inch, round reel tape drives were utilized on mainframe installations. The well known tape itself consists of a thin plastic base material with a coating of ferromagnetic ferric oxide powder. The round reel tapes were physically transported to an offsite location. Periodically, the tapes would be returned and then reused.
In the 1980's, cartridge tape units replaced the round reel tape drives. The tape cartridge system had fewer moving parts and was less prone to failure. Additionally, the tape cartridge system occupies a smaller floor footprint and consumed less power than the round reel drives. Additionally, the media itself was improved over time. Denser recording techniques allowed the cartridges to be smaller, yet hold the same amount of data. To improve cataloging and indexing functions, and facilitate data accessibility, typically one data set is placed on one tape volume. Some tape data sets span multiple volumes while others occupy less than a single volume. This can result in a significant waste of tape as most data sets occupy only a small portion of the media and the rest of the volume remains unused. Estimates are that industry norms are for tape cartridges to be less than 50% utilized. With a cartridge tape system, the same procedures for physically pulling certain cartridges and moving them to an offsite location would be performed.
More recently, virtual tape servers have been introduced which place a controller between a mainframe and the cartridge tape devices and attach a disk cache area from and to which data can be read and written. The controller handles the migration of data between the disk cache and the tape media in an optimal space and time fashion. The data is actually being read from and to disks. The disks are typically faster than tape devices.
Information regarding tape volumes is stored in a tape catalog, maintained by a tape management system running on the host mainframe. The tape management system associates a particular tape using its primary identifier, the tape's volume serial number, with the data sets stored onto it along with its retention, or expiration date. In order to manage the re-use of tapes, the retention date indicates when the data on a tape is no longer required and at such point in time, the tape may have its data overwritten or “scratched” out. Scratch tape is a common mainframe term for a tape available to be written upon, regardless of its prior contents if any.
A scratch list is a report that is generally prepared on a daily basis that includes all of the volume serial numbers whose retention date expired on that day. A human typically refers to this report while walking through a tape library, pulling those tapes on the report so that they may be placed into the scratch pool for reuse. The tape management system imposes a safe guard against non-expired tapes being mounted in place of a scratch tape by comparing the tape's volume serial number against its catalog expiration date. This volume serial number, in addition to being hand written onto the exterior of the tape, is on the beginning of the tape prior to the start of data set information in a section known as a “header”. When a scratch tape is mounted for writing, the tape management system inspects the tape catalog to verify that the tape is truly a scratch. If not, then it is rejected and a different scratch tape requested.
A vault list is a report prepared at some particular time interval that includes all of the volume serial numbers that are to be removed from the tape library and physically taken offsite. Mainframe data centers have the need to move or copy data to off site locations, primarily for the for the purpose of safe keeping critical information to be used in the event of an unexpected loss of the primary copy of that information. This typically involves physical transportation of the mainframe tapes, an error prone process in that sometimes all the required tapes are not sent or sometimes a tape sent in error that is later required to be retrieved in order to complete the processing of a mainframe job. Further, the data on these tapes is typically un-encrypted and therefore vulnerable to anyone being able to read it.
The tape management system is primarily used to cross-reference the location of a desired data set to a tape volume serial number. It is secondarily used to manage scratch lists and vault lists.
The present invention advances the art by allowing its practice to be supported via an encrypted communications protocol interfacing with, and relying upon, the teachings, practices and claims disclosed in U.S. Pat. No. 6,499,108 (hereinafter synonymously referred to as “Secure Agent™” or “SA”).


Plastic pipe is cut by various types of saws. Band saws make reasonably straight cuts. However, band saws are not easily transported to work sites. Hand saws are capable of cutting plastic pipe, but require substantial effort to make straight cuts that are perpendicular to the axis of the pipe. Hand saws are also slow. Powered portable saws of various types are available on job sites. These power saws are generally fast, but make cuts that are not square with the axis of the pipe.
Plastic pipes are used in water supply systems and sewer systems. Water systems and sewage systems both employ plastic pipes with relatively thick walls. Plastic pipes with thick walls are connected together with molded couplings and fittings such as elbows and tees, and adhesives. These fittings generally have internal projections that limit the distance the end of a pipe can be inserted into the fitting. If the cut end surface of a pipe is not in a plane that is perpendicular to the pipe's center line, portions of the end of the pipe cannot be inserted as far into the fitting as required to form a strong joint without leaks. Weak joints may leak the first time they convey a fluid. There is also a chance that weak joints will hold fluids initially but fail later. Unexpected failures and leaks may cause substantial damage.
Plastic pipes are also used for pneumatic systems. These plastic pipes generally have relatively thin walls. Plastics used to make such pipes are semi-rigid. Like the thick walled pipes, molded couplers and fittings are used. Adhesives secure the pipes to the couplers and fittings. Leaks in a pipe system for a central vacuum system, for example, will add air into the system, thereby reducing the effectiveness of the system. Such leaks in a vacuum system are difficult to locate, even if the pipes are accessible. It is therefore imperative that strong joints without leaks be formed.


The present invention relates to a covering for utility vehicle superstructures, and in particular coverings for lateral openings that can swing up when released. More particularly, the invention relates to utility vehicle superstructures having an opening to be covered with a tarpaulin.
Coverings for utility vehicle superstructures, in which a tarpaulin closes off a rear wall and is designed, in particular, as an extension of the tarpaulin cloth of the roof of the utility vehicle body, are known in practice. The tarpaulin is secured laterally by cords and, if appropriate, hooks and eyelets, and, after release of the lateral fastening, can be thrown onto the roof. It is disadvantageous in these known coverings that the closing of the tarpaulin along the lateral edges is complex and, moreover, the tarpaulin can, as a rule, only be thrown up with the aid of relatively long rods or the like, in order to completely free the opening of the vehicle body.
Coverings which automatically roll up and in which a series of spring bars in the tarpaulin are guided from the upper end of the tarpaulin to a tube provided approximately in the centre, are furthermore known in practice, the pretensioning of the springs permitting the tarpaulin to automatically coil up when the lateral connections of the tarpaulin are released, the tarpaulin, when coiled up, being brought together in the manner of a spiral. The tarpaulin can be moved down again, for example by a cord which is provided at a lower edge of the tarpaulin being pulled, the lateral and lower closure of the covering furthermore taking place via cords guided through eyelets or hooks. A disadvantage of a closed covering is that the spring forces in the tarpaulin are not eliminated, and so the covering is generally deformed outward in the region of the points at which the springs engage.
Coverings for utility vehicle superstructures, in which a tarpaulin is provided with a weather strip on the right-hand side and left-hand side, are furthermore known in practice, the tarpaulin having to be thrown by hand onto the roof of the utility vehicle body. To open up the tarpaulin, the lateral weather strips are clamped in each case in a pivoting strip, which can be pivoted in each case about a vertical axis, and the tarpaulin is closed by means of these as well. In this case, it is possible to secure the pivoting strip by an insertable lock or the like. A disadvantage of the known covering is that the throwing-up of the tarpaulin is complex and, moreover, the transported load is secured by the closed tarpaulin only to a limited extent. In addition, the locking pins are frequently lost.
In order to secure a load transported in the utility vehicle body, it is known in practice to diagonally fix tightening straps to the frame of the vehicle body and to the loading platform, the fixing of the tightening straps by hand being labor-intensive and having to take place in a separate working step before the covering is closed.


Irritable bowel disease, Crohn's disease, and Barrett's esophagus are just some of the gastrointestinal diseases that often require biopsy or tissue samples to be taken from the gastrointestinal tract. Often, a large number of biopsy samples must be taken from various locations in the gastrointestinal tract in order to properly diagnose the disease.
Various current biopsy forceps, however, are designed to take only one or two samples in a single pass. Thus, during procedures that require many more tissue samples, up to as many as twenty or more samples in some cases, the forceps must be advanced into and retracted out of the gastrointestinal tract numerous times. Such advancing and retracting of the forceps is time consuming, can cause trauma to the surrounding tissue, and can create sterility issues. Accordingly, a device that minimizes the number of advancements and retractions of the forceps by acquiring and storing multiple biopsy samples in a single pass is desirable. Also desirable is a device that is relatively easy to produce and assemble.


1. Field of the Invention
The present invention is directed to a low pressure plasma generator with a localizable plasma combustion chamber.
2. Discussion of the Background
Treatment with low pressure plasmas is an important new method for modifying the surfaces of solid bodies. The surfaces can be, e.g., etched, i.e., partially removed, or activated, i.e., in an energy-rich state that is suitable for extensive modifications, or are coated by bonding gaseous substances. For all of these methods, the surface to be modified must be subjected to a plasma. As is well-known, a gas comprising excited molecules, radicals or ions is referred to as a plasma.
Plasmas can be generated at low gas pressures by means of microwave radiation. A prerequisite for the formation of a plasma is an adequately high field strength of the radiation. However, the field strength is the greatest in the immediate vicinity of the source of radiation and decreases with increasing distance therefrom. Therefore, the plasma may exist only in the vicinity of the source of radiation.
The uniform treatment of large surfaces or surfaces with complicated shapes with a plasma causes considerable difficulties. For reasons relating to their design and their energy supply, available sources of radiation cannot be disposed at any point and at any position in a low pressure chamber. Similarly, the surface to be treated cannot be moved to specified locations in the plasma combustion chamber. Therefore, the surfaces to be treated cannot be located near the plasma source.
The ability to ignite and maintain a plasma at a predetermined place, where it is supposed to unfold its technological effect, is called localization. The precise localization of plasma is of great importance primarily when a large surface is to be treated uniformly. This goal can be largely reached if one can succeed in localizing a plasma linearly and moving the plasma uniformly over the surface to be treated. For this purpose, either the plasma can be localized stationarily and the substrate can be moved relative thereto or the substrate can remain stationary and the plasma is moved at right angles to its longitudinal extension. However, just the linear localization of a uniform plasma causes considerable difficulties.
The literature reports on various possibilities for localizing microwave plasmas. These include, among others, the ignition of the plasma behind the inlet window for the microwave (Wertheimer et al., Thin Solid Films, 115 (1984), 109), the ignition of primary transmitting aerials (Alcatel DVM, 92240 Malakoff, France, machine GIR 820), the ignition by means of local pressure differences in a vacuum chamber (IKV reports, Mr. Ludwig) and the magnetic confinement with or without the utilization of an electron cyclotron resonance absorption (EP-A 279 895). Some of these possibilities were also used for localizing large area plasmas.
The use of surface waveguide structures, which are mounted outside the vacuum apparatus but which are in front of a microwave permeable window, allows a large area plasma to be ignited (Kieser et al., Thin Solid Films, 118 (1984), 203).
All of the described methods of localization have drawbacks that stand in the way of their practical application. The drawback of the arrangement described last is that the plasma burns only directly behind the window and cannot be moved within the vacuum to any arbitrary place therein by the operator. In the case of a coating plasma, the window is also coated, a feature that can lead to an absorption and reflection of the microwaves depending on the properties of the deposited layer. Long setting-up times then become necessary owing to the repeated cleaning or exchanging of the windows.
An ignition at a primary transmitting aerial yields a plasma whose intensity in most cases exhibits local inhomogeneities owing to the wavelength of the transmitting frequency (e.g., with a period of 12 cm at a frequency of 2.45 GHz). In this arrangement, compensating devices such as a mechanical movement of the aerial can hardly be used owing to the design of primary transmitting aerials
The ability to localize a plasma by means of local pressure differences is limited to the coating of largely closed bodies. This is a suitable method for coating bottles internally. However, in trying to process a flat substrate with such a system grave technological problems arise.
One successful method is magnetic confinement. This process is used, e.g, in the sputter technique. However, an effective magnetic confinement in achieved only if the gyration radius of the charged particles in the plasma with respect to the free path cannot be ignored. This is the case for conventional permanent magnets made of ferrite only below pressures of about 0.1 mbar.
With plasmas of higher pressures--of up to a few millibars--higher etching and deposition rates can be obtained during the etching and coating process. For this reason there is a need for a method for plasma confinement that also has a good localizability at higher pressures and thus allows homogeneous etching or formation of layers at simultaneously high etching and deposition rates.


With the growing availability of mobile devices, individuals may be increasingly exploring the expanding world of mobile applications, games, and social networks. For example, tablet computers may be used to engage children, with and without disabilities, in learning activities through an attractive and easy to use interface and design corresponding to such tablet computers.
Tablet computers may now be equipped with a variety of assets including intuitive user interfaces such as touchscreen, wireless connectivity via multiple different protocols such as Wi-Fi and Bluetooth, image capture capabilities, position sensing and/or location determination capabilities. A variety of applications have been introduced that capitalize on the widespread acceptance of tablet computers, which may, in part, be due to the general affordability. For example, some applications may be operable to offer assistance to individuals with speech difficulties by allowing them to create verbal words and/or phrases by pressing a series of images using a tablet device. Similarly some applications may be operable to combine an interactive drawing application with a robot or other device that may provide feedback based on a user's input sequence. Accessible messages may provide assistive text typing by highlighting keyboard elements as a user types by predicting the next sequence of letters or characters.
Unfortunately, such touch-based tools may be developed assuming that the user possesses fine motor skills and thus is capable of touching small specific regions with an appropriate level of intensity and timing. However, the assumption of fine motor skills may be unwarranted in the context of individuals having limited upper body motor control, including for example, in children with cerebral palsy (CP). For example, children with CP may sustain dysfunctions in upper extremity (UE) activities, such as reaching, grasping and manipulation. Current therapeutic interventions for UE control in children have emphasized repeated practice of functional activities in various contexts with sufficient feedback. However children with CP may have difficulty in accessing devices requiring fine motor control such as, for example, a common pinch and swipe gesture operations that may be used to interface with a tablet computer.


1. Field of the Invention
The present invention relates to an electronic calculator which is capable of operating a numerical expression in sequence of touching the keyboard thereof in accordance with the order from left to right reading along the expression to be calculated, and is capable, in case of an expression including parentheses, of visually indicating in the display unit thereof a temporary answer resultant from operating the portion of the equation between the parentheses. The present invention also relates to an electronic calculator, which visually indicates not only the temporary result derived from a part of an expression between parentheses but any temporary result obtained from an independently operable portion of an expression to be calculated, by discriminating as an arithmetic block any independently operable portion of the expression to execute in turn an arithmetic operation to that portion.
2. Description of the Prior Art
A conventional desktop calculator has been designed with giving importance to the simple system configuration thereof, so that some operational functions might be reduced to a certain extent. For example, when a conventional calculator is operated by touching keys 3, .times., ( , 4, +, 5, ), and = in accordance with a numerical expression 3 .times. (4 + 5) =, the calculator will display or print out only the final result 27, and not any intermediate temporary result derived from a portion of the expression, such as 9 obtained from (4 + 5).
However it is often necessary for an operator to be informed of a temporary result with regard to a portion of an expression to be calculated. Otherwise, an operator must redundantly operate the calculator to obtain the temporary result. In the example described above, when an operator intends to know the result of (4 + 5) as a partial result of the expression, the operator should depress keys 4, +, 5, and = to be informed of the answer 9 visually indicated in the display unit thereof, which answer may be written down on a sheet of paper, and after that the operator will clear all previous settings in the calculator to carry out the remaining operation 3 .times. 9 = by touching keys 3, .times., 9, and =. Then the final answer 27 will be indicated in the display unit. Thus, in a conventional calculator, an operator must discretely twice operate the keyboard thereof in accordance with two numerical expressions such as 4 + 5 = and 3 .times. 9 =. In case of calculating a number of numerical expressions, an operator will be worried by obtaining a lot of the temporary results.
Calculating a numerical expression containing an exponential term, such as 3.sup.2, an operator often intends to known the partial answer, such as 9 in the aforesaid example, resultant from the exponential operation. In that case, the first touching of keys 3, a.sup.x, 2, and = causes the answer 9 to be obtained in a conventional calculator, and then the remaining part of that expression being calculated by employing the intermediate result 9. Thus, a numerical expression containing many independently operable terms should be divided into portions to be partially calculated so as to obtain intermediate result.
Since such a conventional calculator is capable of displaying only the final answer from a numerical expression, it becomes more difficult to check out misoperations in keying before completing the calculation of the expression including more terms. Such a conventional calculator requires relatively more careful operation in keying, causing an operator to be exhausted.


Advancements in media delivery systems and media-related technologies continue to increase at a rapid pace. Increasing demand for media has influenced the advances made to media-related technologies. Computer systems have increasingly become an integral part of the media-related technologies. Computer systems may be used to carry out several media-related functions. The wide-spread access to media has been accelerated by the increased use of computer networks, including the Internet and cloud networking.
Many homes and businesses use computer networks to generate, deliver, and receive data and information between the various connected computers. Users of computer technologies continue to demand increased access to information and an increase in the efficiency of these technologies. Improving the efficiency of computer technologies is desirable to those who use and rely on computers.
With the wide-spread use of computers and mobile devices has come an increased presence of and continued advancements in secure data communications. For example, advancements in mobile devices allow users to make secure connections and virtual private networks (VPNs) with corporate servers. Nevertheless, benefits may be realized by providing systems and methods for improving an authentication process.


At present, large-sized and high-resolution display panel has become a development trend of liquid crystal display device (LCD). However, with increasing of LCD panel size, RC delay of gate wiring and data wiring also increases (as shown in FIG. 1). Excessive RC delay may cause insufficient charging or wrong charging of pixel area, which seriously affects display quality of LCD panel, such as poor display of LCD panel and abnormal image.
In order to solve the aforesaid problem, it is proposed in the prior art that a thickness of a metal layer can be increased. Under the condition that a capacitance is not increased, a resistance is decreased and a signal line load is reduced. However, if the metal layer is too thick, topography of array film will be affected. As a result, a film coated on the metal layer has difficulty in climbing and may break (as shown in FIG. 2), which leads to problems such as corrosion of wiring and short connection. A qualified rate of a product will be seriously reduced. At the same time, there is no planarization technology in traditional array manufacturing procedure, which limits continuous decrease of a signal line resistance.


1. Field of the Invention
This invention relates to electronic components, and particularly to connectors for liquid cooling of electronic components.
2. Description of Background
One method of cooling electronic components, for example, server components disposed in, for example a server rack, is via fluid circulated through the electronic components. The fluid is typically transported to the electronic components in tubing and/or piping and connected to the component with a quick release fitting. One drawback to fluid cooling systems, however, is the risk of electrical hazard from the possible inadvertent spray or splash of fluid onto an electronic component when connecting and/or disconnecting a fitting when servicing the electronic component.


1. Field of the Invention
The present invention relates to non-asbestos friction materials of excellent performance which can be used for braking in automobiles, large trucks, railroad cars and various types of industrial equipment.
2. Prior Art
Friction materials used for braking in automobiles, large trucks, railroad cars and various industrial equipment are desired to have a number of performance features. These features include excellent wear resistance, a friction coefficient that is both high and stable, outstanding resistance to brake fade, no generation of undesirable noises such as squeal during brake operation, and minimal attack of the rotor serving as the counter surface.
The friction material in such cases is generally fabricated by mixing together primarily a fibrous base, a binder and a filler, subjecting the mixed composition to preforming, thermoforming (pressing) and, if necessary, postcuring by heat treatment, then painting, baking and polishing to give a finished article. Mixture of the starting materials may be carried out by dry mixing or by wet mixing using a solvent or water.
However, during mixture of the starting materials, the fibrous substance tends to form clumps (masses of starting material), which discourages uniform dispersion. Also, because hard particles and hard fibrous substances are highly abrasive, inadequate mixture resulting in non-uniform distribution, or segregation, within the friction material leads to a poor friction performance (e.g., noise performance, fading resistance, wear resistance, resistance to counter surface attack, vibration during high-speed braking).
Therefore, one object of the invention is to provide a non-asbestos friction material of outstanding friction performance within which a fibrous substance and hard particles can be uniformly mixed and dispersed so as to enable the capabilities of these friction material constituents to be used to their fullest advantage.
The inventor has learned that by incorporating within a friction material composition particles of a rubber composite composed primarily of either rubber and a fibrous substance or of rubber, a fibrous substance and hard particles, the fibrous substance or the fibrous substance and the hard particles can be blended in a uniformly dispersed state within the friction material, enabling the friction material to exhibit an excellent friction performance.
That is, the inventor has found that the incorporation of rubber composite particles composed primarily of at least one fibrous substance and rubber, or the incorporation of rubber composite particles composed primarily of at least one fibrous substance, at least one type of hard particle and rubber, within a non-asbestos friction material comprised of a molded and cured composition that includes a fibrous base, a binder and a filler allows the uniform mixture and dispersion within the friction material of the fibrous substance or the fibrous substance and the hard particles so that these interlock well with the other constituents to form a non-asbestos friction material in which the capabilities of each constituent are used to fullest advantage. As a result, there can be obtained high-quality non-asbestos friction materials in which counter surface (rotor) attack and the amount of wear due to segregation of the hard particles and hard fibrous substance within the friction material are reduced, noise performance is improved, a decline in the friction coefficient at high temperatures is reliably prevented, and tearing and loss of rubber during brake operation are minimized.
In the non-asbestos friction materials to which the present invention is directed, incorporating particles of a rubber composite composed primarily of soft rubber, a fibrous substance and, according to one embodiment, hard particles within a non-asbestos friction material composition substantially eliminates the drawbacks described above because the fibrous substance, which tends to clump and disperses with difficulty, can be uniformly mixed and dispersed, and because segregation of the hard particles and the hard fibrous substance within the friction material, which causes high abrasiveness and ultimately leads to poor friction performance, such as noise and vibrations, can be prevented.
Also, the rubber within the friction material forms a transfer film on the counter surface (rotor), and so the friction performance is adversely affected by too much transfer or too much abrasion. Therefore, by including in the friction material of the invention particles of a rubber composite composed primarily of either rubber and a fibrous substance or of rubber, a fibrous substance and hard particles, a balance between rubber abrasion and film transfer is achieved. This balance discourages the loss of rubber composite particles from the friction material, leaves the rubber less susceptible to tearing even when subjected to shear forces during friction, and greatly reduces the amount of wear by the friction material. Moreover, loss of these rubber composite particles is less likely to occur even at high brake temperatures, making it possible to assure good performance by the friction material even when it is subjected to friction under high-temperature, high-load, high-speed conditions.
Thus, according to a first aspect of the invention, there is provided a non-asbestos friction material comprising a molded and cured composition that includes (A) a fibrous base, (B) a binder, (C) a filler, and (D) particles of a rubber composite composed primarily of at least one fibrous substance and rubber.
According to a second aspect of the invention, there is provided a non-asbestos friction material comprising a molded and cured composition that includes (A) a fibrous base, (B) a binder, (C) a filler, and (D) particles of a rubber composite composed primarily of at least one fibrous substance, at least one type of hard particle and rubber.
The non-asbestos friction material of the invention is made by incorporating, in a composition of primarily a fibrous base, a binder and a filler, particles of a rubber composite composed primarily of at least one fibrous substance and rubber, or of at least one fibrous substance, at least one type of hard particle and rubber.
The rubber used in the rubber composite particles is not subject to any particular limitation. Exemplary rubbers include acrylonitrile-butadiene rubber (NBR), styrene-butadiene rubber (SBR), chlorobutyl rubber (CBR), silicone rubber, chloroprene rubber (CR), fluororubber (FR), isoprene rubber (IR), natural rubber (NR), butadiene rubber (BR), butyl rubber (IIR), acrylic rubber (AR), urethane rubber (UR), polysulfide rubber (such as that bearing the trade name designation Polysulfide TR), ethylene-propylene rubber (EPM), ethylene-propylene-diene rubber (EPDM) and chlorosulfonated polyethylene (CSM, such as that bearing the trade name designation Hypalon). Any one or combinations of two or more thereof may be used. Of these, acrylonitrile-butadiene rubber (NBR), styrene-butadiene rubber (SBR), chlorobutyl rubber (CBR), silicone rubber, chloroprene rubber (CR) and fluororubber (FR) are preferred.
Use of the rubber in an uncrosslinked (unvulcanized) or semi-crosslinked (semi-vulcanized) state (including partially crosslinked or vulcanized rubber) is advantageous because rubber in this state mixes well with the other constituents such as the fibrous substance and the hard particles, and because crosslinkage (vulcanization) during molding and curing helps to enhance adhesion with the other constituents. In some cases, crosslinked (vulcanized) rubber can be used.
The fibrous substances referred to above include both fibers and fiber components. In the practice of the invention, such substances are divided into hard fibrous substances and soft fibrous substances. Generally, fibrous substances which have the ability to abrade the counter surface (rotor) are called xe2x80x9chard,xe2x80x9d while those which lack this ability and are instead themselves transferred are called xe2x80x9csoft.xe2x80x9d Specifically, for the purposes of the present invention, hard fibrous substances are those having a Mohs hardness of preferably at least 4, more preferably at least 4.5, even more preferably at least 5, and most preferably from 5 to 10. Conversely, soft fibrous substances are those having a Mohs hardness of preferably less than 4, more preferably less than 3.5, even more preferably less than 3, and most preferably from 1 to 3.
The fiber length of the fibrous substance is not subject to any particular limitation, but is generally within a range of about 10 to 5,000 xcexcm, and preferably about 100 to 3,000 xcexcm. Too short a fiber length lowers the strength of the friction material, whereas too great a length increases the abrasiveness to an excessive degree, resulting in excessive wear of the counter surface. Preferably, the aspect ratio of the individual fibers (fiber length/fiber diameter) is within a range of about 10 to 2,000, and especially 10 to 1,000.
At least one type, and preferably 1 to 4 types, of fibrous substance is used in the practice of invention. More specifically, at least one type of hard fibrous substance or at least one type of soft fibrous substance may be used alone, although the use of at least one type of hard fibrous substance in combination with at least one type of soft fibrous substance is preferred.
Exemplary hard fibrous substances include (1) ceramic fibers, (2) natural mineral fibers, (3) glass fibers, and (4) metal fibers. Any one or combinations of two or more of these may be used. Illustrative examples of ceramic fibers include ceramic fibers composed primarily of alumina and silica, ceramic fibers composed primarily of alumina, silica and zirconia, and ceramic fibers composed primarily of silica, calcium oxide and magnesium oxide. Examples of these ceramic fibers that may be used include commercial products such as Ibiden (made by Ibiden Co., Ltd.), S-Fiber SC (made by Thermal Ceramics Division of Nippon Steel Chemical K.K.), Superwool 612 (made by Morgan Crucible) and Fiberflux (made by Toshiba Monoflux K.K.). Illustrative examples of natural mineral fibers include rock wool, wollastonite and sepiolite. Illustrative examples of metal fibers include fibers made of various types of metal, such as steel, stainless steel, bronze, copper and brass.
Exemplary soft fibrous substances include aramid fibers, carbon fibers, cellulose fibers, acrylic fibers and potassium titanate fibers. Any one or combinations of two or more of these may be used. Of these, aramid fibers such as Kevlar(copyright) made by E.I. du Pont de Nemours Co. and Twaron(copyright) made by Akzo Nobel are preferred.
The hard particles used in the invention may be any particles hard enough to abrade cast iron, although particles having a Mohs hardness of at least 4, preferably at least 4.5, more preferably at least 5, and most preferably from 5 to 10, are especially advantageous.
Exemplary hard particles of this type include ceramic particles, metal oxide particles and various types of nitride particles. Any one or combinations of two or more of these may be used.
Illustrative examples include silicon carbide, zirconium oxide, zirconium silicate, alumina, silica, magnesium oxide, iron oxide, titanium oxide, silicon nitride, zinc oxide, aluminum borate and titanium diboride. Of these, silicon carbide, zirconium oxide, zirconium silicate, alumina and silica are preferred.
The size of the hard particles varies according to such factors as the type, hardness and shape of the particles. In general, the particles are limited to a smaller size as the hardness becomes greater, whereas a lower hardness (greater softness) allows particles of a larger size to be used. A higher hardness (larger particle size) results in greater abrasiveness, which restricts the practical range of use of the friction material. Moreover, when the particles have a sharp, angular shape in the manner of broken fragments, for example, they tend to be more abrasive then when they are spherical or surface-treated.
The desired effects of the invention thus tend to become smaller as the hard particles of the invention, assuming the shape to be constant, have a lower Mohs hardness and a smaller size. For example, at a Mohs hardness of 9, it is preferable to use particles having a size of 0.1 to 10 xcexcm, and especially 0.5 to 5 xcexcm. At a Mohs hardness of 5, a particle size of 1 to 500 xcexcm, and especially 5 to 200 xcexcm, is preferred.
When the rubber composite particles in the invention are composed primarily of rubber and a fibrous substance, the amount of the rubber component is preferably 3 to 70% by weight, more preferably 5 to 50% by weight, and most preferably 5 to 35% by weight; and the amount of the fibrous substance is preferably 30 to 97% by weight, more preferably 50 to 95% by weight, and most preferably 65 to 95% by weight. The fibrous substance used in this case may be a hard fibrous substance, a soft fibrous substance, or a combination of both. When a combination of both a soft fibrous substance and a hard fibrous substance is used, any suitable mixing proportions may be selected. The hard fibrous substance accounts for preferably 30 to 97% by weight, and especially 50 to 95% by weight, of the fibrous substance as a whole. The soft fibrous substance accounts for preferably 3 to 70% by weight, and especially 5 to 50% by weight, of the fibrous substance as a whole.
When the rubber composite particles in the invention are composed primarily of rubber, a fibrous substance and hard particles, the amount of the rubber component is preferably 3 to 70% by weight, more preferably 5 to 50% by weight, and most preferably 5 to 35% by weight; the amount of the fibrous substance is preferably 3 to 96% by weight, more preferably 50 to 94% by weight, and most preferably 65 to 94% by weight; and the amount of hard particles is preferably 1 to 50% by weight, more preferably 1 to 30% by weight, and most preferably 1 to 20% by weight. The fibrous substance used in this case may be a hard fibrous substance, a soft fibrous substance, or a combination of both. When a combination of both a hard fibrous substance and a soft fibrous substance is used, any suitable mixing proportions may be selected. The hard fibrous substance accounts for preferably 30 to 97% by weight, and especially 50 to 95% by weight, of the fibrous substance as a whole. The soft fibrous substance accounts for preferably 3 to 70% by weight, and especially 5 to 50% by weight, of the fibrous substance as a whole.
In addition to the foregoing fibrous substance and hard particles, the rubber composite particles of the invention may have added thereto any suitable ingredients commonly used in friction materials. Illustrative examples include, without limitation, cashew dust, rubber powder, resins such as phenol resin, metal powders such as copper, zinc or aluminum, and also mica, vermiculite, graphite, coke, molybdenum disulfide, antimony trisulfide, antimony trioxide, phosphorus-based lubricants, barium sulfate and calcium hydroxide. Of these, the addition of a layered substance such as graphite, coke, mica or vermiculite is advantageous for enhancing the mixing properties.
The rubber composite particles of the invention are produced by first measuring out predetermined amounts of the above-described mixture of rubber and a fibrous substance (such as a combination of a hard fibrous substance and a soft fibrous substance) or mixture of rubber, a fibrous substance (such as a combination of a hard fibrous substance and a soft fibrous substance) and hard particles, and also predetermined amounts of optional materials, if necessary. These materials are loaded into a mixer, then mixed under an applied pressure. Preferably, the starting materials are divided into about two to ten portions and added to the mixer one portion at a time, although the entire amount of the raw materials may be added all at once. Preferable mixing conditions under applied pressure are 20 to 200xc2x0 C. and 1 to 100 kg/cm2 for 1 to 30 minutes, and especially 20 to 100xc2x0 C. and 1 to 100 kg/cm2 for 1 to 30 minutes.
Next, after mixing under applied pressure, it is advantageous for the pressure to be released to 20 kg/cm2 or less, preferably 10 kg/cm2 or less, and especially 5 kg/cm2 or less. A mixing and milling step is then carried out, giving porous (sponge-like) rubber composite particles having a bulk density of preferably not more than 1/2, more preferably from 1/2 to 1/50, and most preferably from 1/5 to 1/20, the theoretical density or specific gravity. If the amount of rubber component in the rubber composite particles is large, it may be transferred to a separate mill, such as a cutting mill, ball mill, Turbomill or jet mill, and there subjected to size reduction.
During mixture of the rubber composite particles, a solvent and a binder may be added to improve adhesion of the rubber with the fibrous substance and the hard particles. The solvent may be any which is capable of swelling and dissolving the rubber. A typical example of a solvent that may be used for this purpose is o-xylene. Illustrative examples of the binder, which may be in either a liquid (solvent) or powder form, include phenol resin, epoxy resin, polyimide resin, polyamide resin and cashew oil. When a solvent is used, drying is necessary. In such cases, it is preferable for milling to be preceded by drying because this facilitates milling and provides better efficiency.
Being endowed with a low bulk density and having a fluffy, porous (sponge-like) nature, the rubber composite particles of the invention, when included in a friction material, are able to ensure that the friction material has the desired porosity and elasticity. In addition, they enhance other properties such as noise performance and resistance to brake fade. The rubber composite particles used in the invention have an average particle size within a range of preferably 50 to 10,000 xcexcm, more preferably 100 to 5,000 xcexcm, even more preferably 300 to 5,000 xcexcm, and most preferably 500 to 2,000 xcexcm. Rubber composite particles with too small an average size may fail to fully achieve the desired effects of the invention, whereas too large a particle size may result in poor mixture within the friction material composition.
When the rubber composite material particles of the invention are mixed into the friction material composition, addition and mixture of the particles into the composition is preferably carried out with the rubber within the rubber composite particles in an uncrosslinked (unvulcanized) or semi-crosslinked (semi-vulcanized) state and together with a vulcanizing agent (crosslinking agent) such as sulfur. Subsequently molding and postcuring (heat-treating) the friction material composition makes it possible to crosslink (vulcanize) the rubber composite particles, resulting in closer adhesion with the other constituents. The vulcanizing agent is generally added in an amount of from 0.05 to 20% by weight, based on the rubber composite particles, although the addition of a vulcanizing agent (crosslinking agent) may be omitted where use is made of a self-crosslinking (self-vulcanizing) rubber. In some cases, the rubber composite particles may first be crosslinked (vulcanized), then added and into the friction material composition.
The rubber composite particles are added in an amount within a range of preferably 1 to 40% by weight, more preferably 1 to 25% by weight, and most preferably 10 to 25% by weight, of the overall friction material composition. The addition of too small an amount of rubber composite particles may make it impossible to achieve the desired effects of the invention; namely, to enable the uniform dispersion and mixing of the fibrous substance without clumping, to enable the uniform dispersion and mixing of the hard fibrous substance and the hard particles within the friction material without segregation, and to use to full advantage the capabilities of the respective ingredients. On the other hand, too large an amount may result in an excessive proportion of organic substances in the friction material, resulting in decreased resistance to brake fade; that is, inferior braking performance at high brake temperatures.
In the non-asbestos friction material of the invention, by adding particles of a rubber composite composed of rubber and a fibrous substance or of rubber, a fibrous material and hard particles to a friction material composition, fibrous substances and hard particles which have hitherto been difficult to disperse and admix, especially hard particles and hard fibrous substances having a high abrasiveness, can be uniformly mixed and dispersed into the friction material, thereby making it possible to use to the fullest advantage the capabilities of each of these constituents.
As explained above, the non-asbestos friction material of the invention is made by molding and curing a friction material composition which includes a fibrous base, a binder, a filler, and the above-described rubber composite particles. No particular limitation is imposed on the constituents other than the rubber composite particles, although a fibrous base (A), a binder (B), and a filler (C) such as are used in conventional friction materials may be employed
The fibrous base serving as component (A) may be, for example, any inorganic or organic fiber commonly used in friction materials, other than asbestos. Illustrative examples include inorganic fibers such as metal fibers (e.g., iron, copper, brass, bronze, aluminum), ceramic fibers, potassium titanate fibers, glass fibers, carbon fibers, rock wool, wollastonite, sepiolite, attapulgite and artificial mineral fibers; and organic fibers such as aramid fibers, polyimide fibers, polyamide fibers, phenolic fibers, cellulose and acrylic fibers. Any one or combinations of two or more thereof may be used.
The fibrous base serving as component (A) may be in the form of staple fibers or a powder. The amount of addition is preferably within a range of 5 to 89% by weight, and especially 20 to 70% by weight, based on the overall friction material composition.
The binder serving as component (B) may be a known binder commonly used in friction materials. Illustrative examples include phenolic resins, melamine resins, epoxy resins, various rubber-modified phenolic resins, and NBR. Any one of these or combinations of two or more thereof may be used.
The amount of binder (B) added is within a range of preferably 5 to 50% by weight, and especially 10 to 25% by weight, based on the overall friction material composition.
The filler serving as component (C) may be any organic or inorganic filler which is known to be used in ordinary frictional materials. Illustrative examples include molybdenum disulfide, antimony trisulfide, calcium carbonate, barium sulfate, magnesium oxide, cashew dust, graphite, calcium hydroxide, calcium fluoride, talc, molybdenum trioxide, antimony trioxide, zirconium silicate, iron oxide, mica, iron sulfide, zirconium oxide, metal powders, quartz, silicon dioxide, rubber powder, alumina, chromium oxide and vermiculite. Any one or combinations of two or more of these may be used.
The amount of filler (C) added is within a range of preferably 5 to 60% by weight, and especially 10 to 40% by weight, based on the overall friction material composition.
The method of making the non-asbestos friction material of the invention involves first uniformly blending components (A), (B) and (C) and the rubber composite particles in a suitable mixer such as a Henschel mixer, Loedige mixer or Eirich mixer so as to give a molding powder, and preforming the powder in a mold. The preform is then molded at a temperature of 130 to 200xc2x0 C. and a pressure of 100 to 1,000 kg/cm2 for a period of 2 to 10 minutes.
The resulting molded article is postcured by heat-treating at 140 to 250xc2x0 C. for 2 to 48 hours, then spray-painted, baked and polished, giving the finished article.
In the case of automotive disk pads, for example, production may be carried out by placing the preform on an iron or aluminum plate that has been pre-washed, surface-treated and coated with an adhesive, then shaping the preform in this state within a mold, and subsequently heat-treating, spray-painting, baking and polishing. This gives a finished disk pad.
The non-asbestos friction materials of the invention are highly suitable for a variety of applications, including brake linings, clutch facings, disk pads, paper clutch facings and brake shoes in automobiles, large trucks, railroad cars and various types of industrial equipment.


The present invention relates to a safety controller for failsafe control of safety-critical processes, and more particularly to a safety controller for failsafe disconnection of a machine or machine system. The invention also relates to a method for loading or transferring a new operating program onto such a safety controller.
For the purposes of the present invention, a safety controller is a device or combination of devices connected to each another, which receive process signals from sensors of a machine or machine system and which use these signals to produce output signals by means of logic operations and, if appropriate, by means of further signal or data processing steps. The output signals are supplied as control signals to actuators which carry out specific actions or reactions in the machine or machine system. One preferred field of application for safety controllers is in the field of machine safety, namely monitoring of emergency stop buttons, two-hand controllers, guard doors, light curtains, stationary or rotary condition monitors and the like. Sensors such as these are used, for example, in order to safeguard a machine which otherwise might cause a hazard to the operator. When the guard door is opened or when the emergency stop button is operated, a process signal is produced which is supplied as an input signal to the safety controller. In response to the input signal, the safety controller switches off the dangerous part of the machine in a failsafe manner, by means of a connected actuator.
A characteristic feature of a safety controller in contrast to a “normal” controller is that the safety controller must always ensure that the process (such as the dangerous machine) being controlled is in a safe state. This requirement even applies when a malfunction occurs within the safety controller or in a device which is connected to it. Safety controllers are therefore subject to extremely stringent requirements for their own failsafety, which results in considerable additional effort during development and manufacture. Generally, safety controllers require special licensing from responsible supervisory authorities before they are used, such as, in Germany for example, from the professional societies dealing with work safety or from a technical supervisory association. The safety controller must comply with specific safety standards which are defined, such as defined in European Standard EN 954-1. The present invention takes account of these special requirements. The expression “safety controller” therefore in this case relates only to a device or a combination of devices which are approved for the control of machines, machine systems and the like in accordance with at least Category 3 of the above-mentioned European Standard.
A programmable safety controller offers the user the capability of individually defining, in accordance with his requirements, the logical operations on the input signals with the aid of software, specifically the so-called user program. A programmable safety controller thus replaces the previously normal wiring to the individual sensors with the aid of logic switching elements. In order to make it possible to carry out this function, a programmable safety controller has an operating program which is separate from the user program and which defines the basic functional scope of the safety controller. In particular, the operating program contains program code by means of which the hardware components of the safety controller are addressed directly and are thus “brought to life”.
Furthermore, safety control rules are also generally implemented in the operating program, which the user program calls up as prepared functional modules and which the user can configure by means of input and output signals at any given time. For example, prepared functional modules for failsafe evaluation of a two-channel emergency-stop button or of a two-channel guard door might be contained in the operating program. In the user program, the user can now only define how the provided modules, i.e. the emergency stop button and the guard door, should be logically linked to one another.
For safety reasons, the user has no access to the operating program, i.e. he can neither replace nor modify the operating program. In the art, the operating program is often referred to as firmware.
WO 98/44399 discloses a method for programming a safety controller in which the safety control rules are stored in the safety controller in the form of functional modules. By means of his user program, the user can select the functional modules, he can configure them and he can logically link them to one another. This is done by means of a programmer, with which the commands for selection, configuration and logic operations on the functional modules are transferred to the safety controller. As explained above, however, it is impossible for the user to access the safety control rules implemented in the functional modules, i.e. he can neither replace them nor modify them.
The inhibited access to the operating program corresponds to the well accepted practice for safety controllers, since the operating program in conjunction with the hardware of the safety controller are subject to licensing by the responsible supervisory authorities. If it were possible for the user to access the combination of hardware and operating program, the manufacturer of the safety controller would not be able to guarantee the failsafety in accordance with the verified certification, according to the general opinion.
However, the common practice has the disadvantage that a functional change in the operating program of the safety controller can be carried out only by the manufacturer of the safety controller himself. If a functional change or an update is desired in the operating program, the user must either send the safety controller to the manufacturer or must request specialist or approved servicing personnel from the manufacturer. This is inconvenient and expensive and, furthermore, may also be disadvantageous in terms of shutdown times for the machine system in which the safety controller is used.
When no safety factors are involved, such as in the case of commercially available personal computers, it is common practice that a user can carry out software updates on his own responsibility by obtaining new software from the manufacturer and loading it onto the personal computer, possibly after instruction. This also applies to so-called operating systems which represent an operating program in the sense of the present invention. According to well established opinion, however, such a procedure is not feasible for safety applications because this would result in the manufacturer of the safety controller losing sole control over the combination of hardware and operating program. In consequence, unchecked combinations of hardware and operating programs would be possible, which would represent a safety risk.


1. Field of the Invention
The present invention pertains to the field of advanced sporting equipment design and in particular to a golf club head system for a putter, driver, or iron designed for control of spin resulting from impact between the club head and a golf ball through elastically tailoring normal and tangential impact compliance.
2. Background Art
The present invention pertains to achieving an increase in the accuracy and distance of a golf club (e.g., a driver, putter or iron) through the application of structural design techniques and elastic tailoring of the club and in particular to enhancing or diminishing ball spins. There have been many improvements over the years which have had measurable impact on the accuracy and distance which a golfer can achieve. Typical passive performance improvements such as head shape and volume, weight distribution and resulting components of the inertia tensor, face thickness and thickness profile, face curvatures and CG locations, all pertain to the selection of optimum constant physical and material parameters for the golf club.
The impact between the ball and the head can be modeled as an impact between two elastic/deformable bodies each having freedom to translate and rotate in space i.e., full 6 degrees of freedom (DOF) bodies, each having the ability to deform at impact, and each having fully populated mass and inertia tensors. The typical initial condition for this event is a stationary ball and high velocity head impacting the ball at a perhaps eccentric point substantially on or substantially off the face of the club head. The impact results in high forces both normal and tangential to the contact surfaces between the club head and the ball. These forces integrate over time to determine the speed and direction, forming velocity vector and spin vectors of the ball after it leaves the face, hereafter called the impact resultants. These interface forces are determined by many properties including elasticity of the two bodies, material properties and dissipation, surface friction coefficients, body masses and inertia tensors.
The present invention pertains to the design of the elastic structural parameters of the head and in particular the attachment between the head body and the face or face insert such that the impact resultants benefit from the elastic/dynamic response of the clubhead under the impact forces. For example the structural design can be such that the face deflections and dynamic response are selected to maximize or minimize ball spin resulting from the impact. There has been much work in the area of elastic tailoring of a golf club head to influence the impact of the head and the ball and the resulting ball flight.
U.S. Pat. No. 4,498,672 to Bulla issued Feb. 12, 1985 discloses a clubhead designed so that the elastic response of the club in the normal direction is tuned such that it's flexure frequency matches a distortion frequency of the ball. The goal is to increase flight distance by increasing the Coefficient of Restitution (COR).
U.S. Pat. No. 5,299,807 to Hutin issued Apr. 5, 1994 discloses a clubhead designed with a thin visco-elastic sheet sandwiched between a face and a club head for improving impact performance and feel. There's no mention of spin, but the patent describes an elastically supported face.
U.S. Pat. No. 5,316,298 to Hutin issued May 31, 1994 discloses a club head designed with a constrained layer visco-elastic damping treatment mounted on the face and or the body for noise tailoring. There's no mention of spin control or control of impact resultants, but the patent discloses an elastically supported face.
U.S. Pat. No. 5,505,453 to Mack issued Apr. 9, 1996, perhaps the closest to the present invention, discloses several (2) designs for an elastically supported impact plate whose support can be tuned to maximize normal response and exiting ball velocity for a given player. It essentially uses advanced analytical models (1-d) normal impact only to determine the optimal support stiffness in the normal direction to maximize ball velocity after impact. The patent shows two designs each applied to drivers, irons and putters. There's no mention of spin, but the patent discloses an elastically supported face.
U.S. Pat. No. 5,674,132 to Fisher issued Oct. 7, 1997 discloses a club head designed with an elastically tailored face insert designed to have an desired rebound factor and/or feel/hardness. There's no mention of spin, but the patent discloses an elastically tailored face.
U.S. Pat. No. 5,697,855 to Aizawar issued Dec. 16, 1997 discloses a clubhead (iron and driver) designed with an elastically supported face insert designed to have a desired damping factor. There's no mention of spin, but the patent discloses an elastically supported face insert.
U.S. Pat. No. 5,807,190 to Krumme et al. issued Sept. 15, 1998 and U.S. Pat. No. 6,277,033 to Krumme et al. issued Aug. 21, 2001 disclose a clubhead (iron and driver—190, and putter—033) designed with an elastically tailored face comprising a number of pixels each selected for its elastic properties and selectively arranged to give a desired face effect (sweet spot etc). There's no mention of spin, but the patent discloses an elastically tailored face design.
U.S. Pat. No. 6,001,030 to Delaney et al. issued Dec. 14, 1999 discloses a club head, (putter only) designed with a face insert constructed “with controlled compression”, i.e., a rigid face impact plate elastically supported where the support is designed to provide a certain normal motion behavior depending on impact intensity and/or impact location. There is no mention of spin, but the patent discloses an elastically tailored face design.
U.S. Pat. No. 6,302,807 to Rohrer issued Oct. 16, 2001 discloses a golf club head (preferably putter) designed with variable energy absorption. It discloses designs for viscoelastic supported faces constructed to maximize dissipation in ideal hits and lower dissipation in off center miss-hits. There's no mention of spin, but the patent discloses an elastically tailored face design.
U.S. Pat. No. 6,328,661 to Helmstetter et al. issued Dec. 11, 2001 and U.S. Pat. No. 6,478,690 to Helmstetter et al. issued Nov. 12, 2002, “Multiple Material Golf Club Head with a Polymer Insert Base” disclose a golf club head (preferably putter) designed with a polymer face insert of carefully defined hardness and rebound i.e., an elastically tailored insert to effect impact COR and feel.
U.S. Pat. No. 6,332,849 to Beasley et al. issued Dec. 25, 2001, “Golf Club Driver with Gel Support of Face Wall” discloses a golf club head (preferably driver) designed with a viscoelastic member supporting the face and connected between the center of the face and the back of the hollow body of the clubhead.
U.S. Pat. No. 6,354,961 to Allen issued Mar. 12, 2002, “Golf Club Face Flexure Control System” discloses a golf club head (preferably driver) designed with a pneumatic piston/cylinder supporting the face and connected between the center of the face and the back of the hollow body of the clubhead. The piston is designed to make contact and change effective stiffness in a predetermined impact velocity range.
U.S. Pat. No. 6,364,789 to Kosmatka issued Apr. 2, 2002, “Golf Club Head” discloses a golf club head designed with an annular deflection enhancement member disposed between the club head body and a stiff face. The stiffness of the annular member is preferably lower then the face to enhance deflection of the face at impact and increase COR.
U.S. Pat. No. 6,478,693 to Matsunaga et al. issued Nov. 12, 2002, “Golf Club Head” discloses a golf club head (preferably driver or iron) designed with a variable thickness face with step changes in multiple tiered thickness regions. The centroids of the regions are designed and located to maximize the region of uniformity of strike response—i.e., increase the sweet spot under normal impact.
U.S. Pat. No. 6,488,594 to Card et al. issued Dec. 3, 2002, “Putter with a consistent Putting Face” discloses a putter designed with a face insert designed to maximize dissipation in ideal hits and lower dissipation in off center miss-hits. There's no mention of spin, but the patent discloses an elastically tailored face design.
U.S. Pat. No. 6,592,468 to Vincent et al. issued Jul. 15, 2003, “Golf Club Head” discloses a golf club head designed with a viso-elastically supported insert for increasing the damping in vibrations in the club caused by impact.
U.S. Pat. Nos. 6,595,057 and 6,605,007 to Bissonnette et al. issued Jul. 22, 2003 and Aug. 12 2003, respectively, “Golf Club Head with High Coefficient of Restitution” discloses a golf club with a face whose thickness is tailored to maximize COR. The face has a higher stiffness central zone and a lower stiffness surrounding zone.
U.S. Pat. No. 6,602,150 to Kosmatka issued Aug. 5, 2003, “Golf Club Striking Plate with Vibration Attenuation” discloses a golf club with a variable thickness face (thicker central portion) on which is disposed a viscoelastic material for face vibration attenuation.
All of the aforementioned patents deal with clubhead designs such that the elastic response of the head and face during impact impart a benefit to feel and or COR of the clubhead. None of the aforementioned patents has addressed the design of the elastic/dynamic response of the clubhead so as to effect beneficial control of the ball spin. U.S. Pat. No. 5,193,806 to Burkly issued Mar. 16, 1993, discloses a clubhead designed with a circular shape contact surface to effect spin control, but does not teach the use of clubhead elastic response to achieve this. The face is assumed to be rigid. Numerous patents have attempted to address spin control through surface treatments of the contacting bodies, but none directly address control of spin by elastic/structural design of the clubhead.


1. Technical Field
Methods and example implementations described herein are directed to an interconnect architecture, and more specifically to systems and methods for implementing visual and/or graphical representation of NoC performance based on outcome of simulation conducted on one or a combination of Network on Chip (NoC) interconnects and/or System on Chip (SoC) architectures.
2. Related Art
The number of components on a chip is rapidly growing due to increasing levels of integration, system complexity and shrinking transistor geometry. Complex System-on-Chips (SoCs) may involve a variety of components e.g., processor cores, DSPs, hardware accelerators, memory and I/O, while Chip Multi-Processors (CMPs) may involve a large number of homogenous processor cores, memory and I/O subsystems. In both SoC and CMP systems, the on-chip interconnect plays a role in providing high-performance communication between the various components. Due to scalability limitations of traditional buses and crossbar based interconnects, Network-on-Chip (NoC) has emerged as a paradigm to interconnect a large number of components on the chip. NoC is a global shared communication infrastructure made up of several routing nodes interconnected with each other using point-to-point physical links denoting connectivity and direction of data flow within the SoC and the NoC.
Messages are injected by the source and are routed from the source node to the destination over multiple intermediate nodes and physical links. The destination node then ejects the message and provides the message to the destination. For the remainder of this application, the terms ‘components’, ‘blocks’, ‘hosts’ or ‘cores’ will be used interchangeably to refer to the various system components, which are interconnected using a NoC. Terms ‘routers’ and ‘nodes’ will also be used interchangeably. Without loss of generalization, the system with multiple interconnected components will itself be referred to as a ‘multi-core system’.
There are several topologies in which the routers can connect to one another to create the system network. Bi-directional rings (as shown in FIG. 1(a)), 2-D (two dimensional) mesh (as shown in FIG. 1(b)) and 2-D Torus (as shown in FIG. 1(c)) are examples of topologies in the related art. Mesh and Torus can also be extended to 2.5-D (two and half dimensional) or 3-D (three dimensional) organizations. FIG. 1(d) shows a 3D mesh NoC, where there are three layers of 3×3 2D mesh NoC shown over each other. The NoC routers have up to two additional ports, one connecting to a router in the higher layer, and another connecting to a router in the lower layer. Router 111 in the middle layer of the example has both ports used, one connecting to the router at the top layer and another connecting to the router at the bottom layer. Routers 110 and 112 are at the bottom and top mesh layers respectively, therefore they have only the upper facing port 113 and the lower facing port 114 respectively connected.
Packets are message transport units for intercommunication between various components. Routing involves identifying a path composed of a set of routers and physical links of the network over which packets are sent from a source to one or more destination components. Components are connected to one or multiple ports of one or multiple routers; with each such port having a unique ID. Packets carry the destination's router and port ID for use by the intermediate routers to route the packet to the destination components.
Examples of routing techniques include deterministic routing, which involves choosing the same path from A to B for every packet. This form of routing is independent from the state of the network and does not load balance across path diversities, which might exist in the underlying network. However, such deterministic routing may implemented in hardware, maintains packet ordering and may be rendered free of network level deadlocks. For example, shortest path routing may minimize the latency, as such routing reduces the number of hops from a source to one or more destination(s) and/or reduces the cost of routing a packet from the source to destination(s), wherein the cost of routing depends on bandwidth available between one or more intermediate elements/channels. For this reason, the shortest path may also be the lowest power path for communication between the two components. Dimension-order routing is a form of deterministic shortest path routing in 2-D, 2.5-D, and 3-D mesh networks. In this routing scheme, messages are routed along each coordinates in a particular sequence until the message reaches the final destination. For example in a 3-D mesh network, one may first route along the X dimension until it reaches a router whose X-coordinate is equal to the X-coordinate of the destination router. Next, the message takes a turn and is routed in along Y dimension and finally takes another turn and moves along the Z dimension until the message reaches the final destination router. Dimension ordered routing may be minimal turn and shortest path routing.
FIG. 2(a) pictorially illustrates an example of XY routing in a two dimensional mesh. More specifically, FIG. 2(a) illustrates XY routing from node ‘34’ to node ‘00’. In the example of FIG. 2(a), each component is connected to only one port of one router. A packet is first routed over the x-axis until the packet reaches node ‘04’ where the x-coordinate of the node is the same as the x-coordinate of the destination node. The packet is next routed over the y-axis until the packet reaches the destination node.
In heterogeneous mesh topology in which one or more routers or one or more links are absent, dimension order routing may not be feasible between certain source and destination nodes, and alternative paths may have to be taken. The alternative paths may not be shortest or minimum turn.
Source routing and routing using tables are other routing options used in NoC. Adaptive routing can dynamically change the path taken between two points on the network based on the state of the network. This form of routing may be complex to analyze and implement.
A NoC interconnect may contain multiple physical networks. Over each physical network, there may exist multiple virtual networks, wherein different message types are transmitted over different virtual networks. In this case, at each physical link or channel, there are multiple virtual channels; each virtual channel may have dedicated buffers at both end points. In any given clock cycle, only one virtual channel can transmit data on the physical channel.
The physical channels are time sliced into a number of independent logical channels called virtual channels (VCs). VCs provide multiple independent paths to route packets, however they are time-multiplexed on the physical channels. A virtual channel holds the state needed to coordinate the handling of the flits of a packet over a channel. At a minimum, this state identifies the output channel of the current node for the next hop of the route and the state of the virtual channel (idle, waiting for resources, or active). The virtual channel may also include pointers to the flits of the packet that are buffered on the current node and the number of flit buffers available on the next node.
NoC interconnects may employ wormhole routing, wherein, a large message or packet is broken into small pieces known as flits (also referred to as flow control digits). The first flit is the header flit, which holds information about this packet's route and key message level info along with payload data and sets up the routing behavior for all subsequent flits associated with the message. Optionally, one or more body flits follows the head flit, containing the remaining payload of data. The final flit is the tail flit, which in addition to containing the last payload also performs some bookkeeping to close the connection for the message. In wormhole flow control, virtual channels are often implemented.
The term “wormhole” plays on the way messages are transmitted over the channels: the output port at the next router can be so short that received data can be translated in the head flit before the full message arrives. This allows the router to quickly set up the route upon arrival of the head flit and then opt out from the rest of the conversation. Since a message is transmitted flit by flit, the message may occupy several flit buffers along its path at different routers, creating a worm-like image.
Based upon the traffic between various end points, and the routes and physical networks that are used for various messages, different physical channels of the NoC interconnect may experience different levels of load and congestion. The capacity of various physical channels of a NoC interconnect is determined by the width of the channel (number of physical wires) and the clock frequency at which it is operating. Various channels of the NoC may operate at different clock frequencies, and various channels may have different widths based on the bandwidth requirement at the channel. The bandwidth requirement at a channel is determined by the flows that traverse over the channel and their bandwidth values. Flows traversing over various NoC channels are affected by the routes taken by various flows. In a mesh or Torus NoC, there may exist multiple route paths of equal length or number of hops between any pair of source and destination nodes. For example, in FIG. 2(b), in addition to the standard XY route between nodes 34 and 00, there are additional routes available, such as YX route 203 or a multi-turn route 202 that makes more than one turn from source to destination.
In a NoC with statically allocated routes for various traffic slows, the load at various channels may be controlled by intelligently selecting the routes for various flows. When a large number of traffic flows and substantial path diversity is present, routes can be chosen such that the load on all NoC channels is balanced nearly uniformly, thus avoiding a single point of bottleneck. Once routed, the NoC channel widths can be determined based on the bandwidth demands of flows on the channels. Unfortunately, channel widths cannot be arbitrarily large due to physical hardware design restrictions, such as timing or wiring congestion. There may be a limit on the maximum channel width, thereby putting a limit on the maximum bandwidth of any single NoC channel.
Additionally, wider physical channels may not help in achieving higher bandwidth if messages are short. For example, if a packet is a single flit packet with a 64-bit width, then no matter how wide a channel is, the channel will only be able to carry 64 bits per cycle of data if all packets over the channel are similar. Thus, a channel width is also limited by the message size in the NoC. Due to these limitations on the maximum NoC channel width, a channel may not have enough bandwidth in spite of balancing the routes.
To address the above bandwidth concern, multiple parallel physical NoCs may be used. Each NoC may be called a layer, thus creating a multi-layer NoC architecture. Hosts inject a message on a NoC layer; the message is then routed to the destination on the NoC layer, where it is delivered from the NoC layer to the host. Thus, each layer operates more or less independently from each other, and interactions between layers may only occur during the injection and ejection times. FIG. 3(a) illustrates a two layer NoC. Here the two NoC layers are shown adjacent to each other on the left and right, with the hosts connected to the NoC replicated in both left and right diagrams. A host is connected to two routers in this example—a router in the first layer shown as R1, and a router is the second layer shown as R2. In this example, the multi-layer NoC is different from the 3D NoC, i.e. multiple layers are on a single silicon die and are used to meet the high bandwidth demands of the communication between hosts on the same silicon die. Messages do not go from one layer to another. For purposes of clarity, the present disclosure will utilize such a horizontal left and right illustration for multi-layer NoC to differentiate from the 3D NoCs, which are illustrated by drawing the NoCs vertically over each other.
In FIG. 3(b), a host connected to a router from each layer, R1 and R2 respectively, is illustrated. Each router is connected to other routers in its layer using directional ports 301, and is connected to the host using injection and ejection ports 302. A bridge-logic 303 may sit between the host and the two NoC layers to determine the NoC layer for an outgoing message and sends the message from host to the NoC layer, and also perform the arbitration and multiplexing between incoming messages from the two NoC layers and delivers them to the host.
In a multi-layer NoC, the number of layers needed may depend upon a number of factors such as the aggregate bandwidth requirement of all traffic flows in the system, the routes that are used by various flows, message size distribution, maximum channel width, etc. Once the number of NoC layers in NoC interconnect is determined in a design, different messages and traffic flows may be routed over different NoC layers. Additionally, one may design NoC interconnects such that different layers have different topologies in number of routers, channels and connectivity. The channels in different layers may have different widths based on the flows that traverse over the channel and their bandwidth requirements.
In a NoC interconnect, if the traffic profile is not uniform and there is a certain amount of heterogeneity (e.g., certain hosts talking to each other more frequently than the others), the interconnect performance may depend on the NoC topology and where various hosts are placed in the topology with respect to each other and to what routers they are connected to. For example, if two hosts talk to each other frequently and require higher bandwidth than other interconnects, then they should be placed next to each other. This will reduce the latency for this communication, which thereby reduces the global average latency, as well as reduce the number of router nodes and links over which the higher bandwidth of this communication must be provisioned.
With the number of on-chip components growing, NoC and SoC being configured to support multiple traffic profiles/transactions/messages having different latency, throughput, and data size characteristics need to be simulated for their performance, and therefore visualization and/or graphical representation of the simulation output including comparison, merging, and conducting other such actions on one or more simulation results becomes necessary in order to evaluate the performance attributes of SoC agents, NoC elements, and/or the NoC channels that form part of the interconnect under varying traffic conditions. There is therefore a need in the art for methods, systems, and non-transitory mediums that can be can be configured for visualization and performance characterization of SoC and/or NoC for one and more transactions.