(a) Fields of the Invention
The present invention relates to solid-state image sensing devices having a solid-state image sensing element and a transparent substrate for protecting the element, and to their fabrication methods.
(b) Description of Related Art
In a solid-state image sensing device employing a CCD (Charge Coupled Device) and the like, the area of a photodiode serving as a light receiving unit has been decreasing by demands for downsizing and resolution enhancement thereof. Such a decrease in the area of the light receiving unit in turn degrades the light collection efficiency of the device. In order to make up for this degradation, a so-called microlens has come to be developed and then put into use. This microlens is typically made of resin and disposed above the light receiving unit formed on each pixel. The microlens refracts light not coming directly in the light receiving unit to collect the refracted light into the light receiving unit, thereby enhancing light collection efficiency to improve sensitivity.
FIGS. 15 and 16 show cross-sectional structures of a conventional solid-state image sensing device. Referring to FIG. 15, in the surface of a substrate 101 for a CCD-type solid-state image sensing element, a recess is provided on each pixel. At the bottom of the recess, a photodiode 102 is provided which converts an incoming light into an electrical signal. On the substrate 101 for the solid-state image sensing element, a first acrylic flattening film 103 is formed which flattens unevenness of the substrate surface. On the first acrylic flattening film 103, color filters 104 are formed to be associated with the photodiodes 102, respectively. On the color filters 104, a second acrylic flattening film 105 is formed which flattens unevenness generated due to gaps between the color filters 104. On the second acrylic flattening film 105, microlenses 106 are formed to be associated with the photodiodes 102, respectively.
Referring to FIG. 16, a solid-state image sensing element 113 is composed of the photodiodes 102, the color filters 104, the microlenses 106, and the like formed on the substrate 101 for the solid-state image sensing element. The solid-state image sensing element 113 is mounted inside a package 112, and the top of the package 112 is covered with a transparent substrate 109. As shown in FIG. 15, inside the package 112, an air space 110 is interposed between the solid-state image sensing element 113 and the back surface of the transparent substrate 109. As shown in FIG. 15, when light 111 transmits through the transparent substrate 109 to come in the microlenses 106, reflections occur on the top and bottom surfaces of the transparent substrate 109 and the top surfaces of the microlenses 106.
However, rapid downsizing of the device in recent years has made it difficult to secure sufficient sensitivity only by light collection from the microlenses. To overcome such a difficulty, a structure such that an antireflection film is formed on the microlenses is proposed (see Patent Document 1: Japanese Patent No. 2719238).
(Patent Document 2)
Japanese Examined Patent Publication No. 7-54974
(Patent Document 3)
Japanese Examined Patent Publication No. 7-28014
(Patent Document 4)
Japanese Patent No. 2942369


Concrete is traditionally used for floors in both residential and commercial applications in view of its robustness and economic benefits. Depending upon the circumstances, the concrete may be left unfinished, partially finished or completely finished wherein a high gloss decorative service is obtained.
In warehouses, factories, etc., concrete floors are routinely cleaned by rotary driven machines that employ brushes located on the underside of the machinery whereby the machinery traverses the floor to provide a clean surface. Typically these floor cleaning machines have a tendency of progressively deteriorating the surface of the concrete floor. This is caused by the bristles extending into the naturally occurring crevices in the concrete floor thus causing minute particles of the concrete to break away. Through the repeated cleaning utilizing this floor polishing machine is then typically employed to treat the surface of the floor so as to restore the floor back to a desirable appearance.
Typically the flooring machines that are used on a routine basis sit idle as they have a limited purpose, which is to clean the floor. These traditional flooring machines are not used to polish the floor, but merely for the single purpose of cleaning the floor. Likewise, a separate floor polishing machine traditionally is used for the sole purpose of polishing the concrete floor when the floor condition has sufficiently deteriorated. Accordingly, because these machines have limited purposes, they are seldom used, thus creating inefficiencies for a business.
It will be desirable to forego the aforementioned costly steps by providing an improved cleaning and honing brush that works as an attachment to an ordinary cleaning machine, such as a Tennant or Advance brand scrubber machine. It would be desirable to provide an improved cleaning and honing brush that operates under low pressure, does not require an independent power source, continuously exposes new abrasive material during the cleaning process and has interchangeable replaceable polymer brush strips that can be easily removed and replaced with replacement polymer brush strips.
The aforementioned problems may be overcome by providing a polymer brush strip that may be co-extruded with diamond particles integral with the head of the brush strip.
It will further be desirable to provide a floor resurfacing device that operates under low speed and low pressure conditions while utilizing a diamond impregnated brush made of polymer matrix that can be used on ordinary rotary machines including low power, low pressure automatic flooring machines.
It will be desirable to provide an improved polishing system that can be used in connection with a traditional automatic flooring machine wherein a series of diamond embedded polymer strips are used with a rotary disc. The rotary disc bearing the polymer strips can also be used for cleaning the surface of the concrete as well as providing a polishing aspect during the process of cleaning. The floor cleaning process employs a rotary disc having polymer strips with greater grit density so as to provide an improved surface finish. The process is repeated routinely whereby at each cycle the polymer strips are changed out to have finer grit size so as to continuously enhance the surface finish quality. The aforementioned process is accomplished while cleaning the floor during low speed and low pressure conditions. Said process can be used with floors other than concrete floors.
The present invention also solves a problem that is found in the maintenance of floors in offices. For example, in office settings a common floor covering is vinyl composite tile (VCT). Wax is often applied over the tile so as to protect its surface and to provide an enhanced floor appearance. Over time these floors acquire a build up of wax and other particles that need to be removed so as to reestablish the floor's appearance to a new-like condition. Traditionally, a common way of stripping wax and other particles from floors was to use chemicals. The chemicals loosen the wax so it can then be removed via a scrubbing process. Typical ways of removing the loosened wax were to use an abrasive pad. However, the loosened wax tends to gum up the surface of the pad making removal very difficult. It would be preferred to provide a more environmentally green method of stripping wax from VCT, for example, use of water would be preferred. In order to accomplish complete removal of wax from VCT, an improved pad driver with brush design would be desirable. It would also be desirable to provide an improved brush that has a polymer component with a metal component.


1. Field of the Invention
This invention relates to a three way sliding poppet valve for switching high pressure, high temperature fluids under low pressure control and, in particular, this invention relates to a low internal volume three way valve for high speed switching of high pressure, high temperature fluids without volume change for precision laboratory measurements such as is encountered in permeameter tests with corrosive fluids involving core samples.
2. Description of the Prior Art
In permeameter tests, high temperature (such as 280 degrees Fahrenheit) and high pressure (such as 10,000 psi) corrosive fluids (such as brine, oil, and gas) are injected into core samples to measure relative or specific permeability of the core sample. A computer operated permeameter requires a multi-port, three way valve capable of zero volume change and having low internal volume as well as a rapid response time. One prior art approach used VALCO rotary valves such as those manufactured by Valco Instruments, Inc., P.O. Box 55603, Houston, Tex. 77255. These rotary valves, however, have small flow paths and a slow response time such as 0.5-2.0 seconds.
Prior to the filing of the present invention, a patentability search was conducted resulting in the following patents:
______________________________________ Inventor Patent No. Date ______________________________________ C. M. Carlson 3,002,532 10-03-61 N. C. Hunt 3,016,917 01-16-62 Maurice F. Franz 3,570,541 03-16-71 Gerald Sorenson 3,587,156 06-28-71 Gerald Sorenson 3,762,443 10-02-73 Stoll et al. 3,794,075 02-26-74 Brake et al. 3,902,526 09-02-75 Charles Perkins 4,027,700 06-07-77 Erich Ruchser 4,067,357 01-10-78 Paul Arvin 4,103,711 08-01-78 Clifford Peters 4,209,040 06-24-80 Clifford Peters 4,217,934 08-19-80 Coppola et al. 4,567,914 02-04-86 ______________________________________
The 1971 and 1973 patents to Sorenson pertain to the method of manufacturing a pressurized fluid control valve utilizing a valve spool centrally located in a valve body. The embodiment shown in FIG. 17 of Sorenson shows a multi-passage valve utilizing a symmetrically shaped spool wherein the spool has an incline surface that seats against a sharp circular edge formed in the body. The Sorenson spool or valve body is constructed of deformable resilient materials such as polyurethane, neoprene, polyethylene, or rubber. Deformability of the valve spool or body of Sorenson is critical since in the manufacturing of the valve, the spool or body must deform in order to be inserted into the body. After the insertion, the deformed part recovers to its original condition. In such an embodiment, the forces of deformation are much greater than the forces experienced by the valve in operation. As such, it is believed that the valve of Sorenson would not be suitable to the high temperature, high pressure environments for which the valve of the present invention is ideally suited. Furthermore, Sorenson requires fluid exhaust ports. The present invention has no exhaust ports since it is applied to the flow of high pressure, high temperature fluids which must be completely contained within the valve. Sorenson relies on multiple annular rings providing simultaneous multiple seals caused by moving the spool. The current invention requires only one sealing surface to contact the spool at a time. Sorenson valves are commonly known as 4-way valves, whereas the present valve is specifically a 3-way valve. Finally, the present valve provides means of applying very large forces to a sealing line formed by the poppet (or spool) contacting the sealing surface in the body, namely the large diameter pistons.
The 1974 patent to Stoil U.S. Pat. No. (3,794,075) sets forth a multi-way valve having a switching time of six milliseconds and exhibiting short physical valve travel. The Stoll invention makes use of disc plane seals located on a symmetrical center spool. The spool is driven by the snap action of opposing diaphragms which are hydraulically activated. The rubber diaphragms comprising the spool end seals and snap action diaphragms make this valve unsuitable for high pressure applications. High internal pressures would collapse these parts causing the valve to fail. The central O-ring seal of the spool is not constrained so that back pressure on the seal would unseal the O-ring causing leakage. This is not the case in the present invention. Because of flexure of the rubber parts some internal volume change must occur in the Stoll valve after the seals make initial contact. This volume change will compress the fluid in one part of the valve causing a pressure change. This problem does not exist in the present invention. Under high differential pressure the unsupported elastomeric seals used by Stoll may experience extrusion. The problem is accentuated at high temperature. The present valve uses metallic sealing surfaces to eliminate the problem.
The 1962 patent issued to Hunt (U.S. Pat. No. 3,016,917) sets forth a valve for controlling high pressure fluid. The valve plunger of Hunt has an enlarged central body portion terminating in an angled seating surface on an enlargement of the valve which selectively abuts against a corresponding angled seat in the cavity. Hunt utilizes a metal to metal engagement between the valve enlargement and the seat to provide a seal against leakage of fluid pressure. The valve is held in the closed position by means of a solenoid and is returned to the opened condition by means of a spring. In this embodiment the central valve spool is not hydrostatically balanced.
The 1971 patent to Franz (U.S. Pat. No. 3,570,541) sets forth a three way directional control valve having a formed poppet member located internally to a body wherein the body has internally disposed conically shaped seats for selective engagement with the poppet member to open and close the three way valve. The poppet member and seat incorporate an elastomeric material. The Franz valve is designed to operate at 100 psi with an activating piston driven valve control operating at 70 psi.
The 1986 patent to Coppola (U.S. Pat. No. 4,567,914) relates to a two-stage hydraulic solenoid valve having a centrally disposed poppet member having incline surfaces that selectively seat with conical seats. The Coppola invention is designed for steam turbine control systems.
The 1978 patent to Ruchser (U.S. Pat. No. 4,067,357) relates to a sliding/spool direction control valve wherein the spool is of symmetrical construction and is driven by two opposing control pistons. The Ruchser embodiment provides a novel seating arrangement that selectively seals despite loss of tolerances due to wear, manufacturing, or use.
The remaining patents uncovered in the search are not as pertinent to the present invention as those discussed above.