An illuminated vehicle display device comprising a flat back plate having a light source disposed thereon, and a front, box-like housing member which has a rearwardly disposed opening so that the housing member encloses the light source when it is detachably attached to the flat back plate. The front housing member has a partially translucent/transparent (i.e. partially non-opaque) panel disposed in a window defined through its front wall. A plurality of protruding tab members defined on the inside faces of one or more walls of the housing member coact with a plurality of corresponding slots defined in the back plate to simply, securely and detachably snap fasten the housing member to the back plate. Electrical power wires threaded through a hole in the back plate are used to connect the light source to an external power supply. The back plate is mountable to a vehicle license plate mounting assembly. Thus, when fully assembled and in use, light emanating from the light source passes through the non-opaque portions of the display panel to create an illuminated visual image.

Illuminated license plates and illuminated display panels which may be attached to a motor vehicle in lieu of a license plate are well known in the art. Many of such prior devices involve illumination of the license plate or the display panel by shining light onto the face of the plate or panel. In such devices, the light source is disposed outside and in front of the plate or panel face to radiate light onto opaque display indicia disposed on this face which in turn reflects the light to the viewer, thus illuminating the display indicia.
Other prior art devices were developed which were not dependent on reflection of exterior light but instead involved one or more light sources which were disposed inside a housing behind a display face. Such a light source would then shine light through transparent or translucent portions of the display face to illuminate the desired display indicia for the viewer.
This latter form of illuminated display device has taken many forms and involves numerous different features. Two recent examples include Munoz (U.S. Pat. No. 4,475,298) and Monroe (U.S. Pat. No. 5,073,842). Both of these patents generally disclose a box-like light source housing having a forwardly disposed opening in which a partially translucent or otherwise partially non-opaque display panel is mounted. The light source in each housing emits light that passes through the translucent or non-opaque portions of the associated display panel to create an illuminated image.
A principal distinction between Munoz and Monroe (and between other devices similar to each) is that where the Monroe device first transmits light through air within its substantially vacant housing, the Munoz housing is filled with a solid, light-conductive/light-transmitting material upon which is overlaid a partially opaque shield having non-opaque portions formed therein. Light is then directed into an edge of the Munoz light-conductive material which disseminates the light to illuminate the entire display area. The visual image is created by the light which emanates from the display material through the non-opaque portions of the shield. Other examples of illumination devices using similar light-conductive materials are disclosed in the U.S. Patents to Aronoff (U.S. Pat. No. 3,349,511), O'Donnell (U.S. Pat. No. 3,406,475), Redick (U.S. Pat. No. 5,150,960), and Ching Hwei (U.S. Pat. No. 5,177,889). Note that Redick and Ching Hwei describe devices which combine elements of the exterior reflection devices (discussed generally above) with the use of light-conductive materials.
On the other hand, the Monroe device (introduced above), is effective without the use of a solid, light-conductive material. In Monroe, light emits from a light source in the housing and radiates through the air in the housing and then out through the non-opaque portions of the display panel mounted in its forwardly disposed opening. Other U.S. Patents for similar devices include those to Marsala (U.S. Pat. No. 2,045,863), Marks (U.S. Pat. No. 2,108,591) Czarny et al. (U.S. Pat. No. 2,122,027), Rioux (U.S. Pat. No. 2,124,829), Dunnam et al. (U.S. Pat. No. 2,156,753), Ducey (U.S. Pat. No. 2,156,806), White (U.S. Pat. No. 2,171,820), Hoover et al. (U.S. Pat. No. 2,203,785), Aydelotte (U.S. Pat. No. 2,305,372), Vokaty (U.S. Pat. No. 2,305,750), Gladd (U.S. Pat. No. 2,875,539), Murai (U.S. Pat. No. 3,521,391) and Flannery (U.S. Pat. No. 3,921,324).
Even in view of the voluminous prior efforts in this art, there still remains a need for illuminated display devices that have improved features for use and easy installation and which reduce light and water leakage. For example, a problem with the Monroe-like devices is that when one is mounted on the front of a motor vehicle, the seam between the display plate and housing where these components engage is subject to light and water leakage. Light leakage can impair the display image of the device while water can affect its operability and/or substantially reduce its effective life. Note, Monroe does address this problem by teaching the placement of a gasket in this seam particularly to combat water entry. Further, the standard screw attachments of the display plates to the prior art housings are relatively complex in that they require laborious and time-consuming efforts, both during installation and in maintaining, replacing or repairing interior elements such as a light source or a display panel.


A method for manufacturing a stamped part, such as a bipolar plate for a fuel cell, includes the steps of: providing an original model of the bipolar plate; and performing a compensation process on the original model, the compensation process including a two step morphing process based upon a prediction of spring back. The two step morphing process provides a compensated model of the stamped part. A compensated die face may be created based on the compensated model of the stamped part. The stamped part manufactured with the compensated die face has spring back compensation.

A fuel cell has been proposed as a clean, efficient and environmentally responsible power source for various applications. In particular, individual fuel cells can be stacked together in series to form a fuel cell stack capable of supplying a quantity of electricity sufficient to power an electric vehicle. The fuel cell stack has been identified as a potential alternative for a traditional internal-combustion engine used in modern vehicles.
Fuel cells are electrochemical devices which combine a fuel such as hydrogen and an oxidant such as oxygen to produce electricity. The oxygen is typically supplied by an air stream. The hydrogen and oxygen combine to result in the formation of water. Other fuels can be used such as natural gas, methanol, gasoline, and coal-derived synthetic fuels, for example.
One type of fuel cell is known as a proton exchange membrane (PEM) fuel cell. The PEM fuel cell typically includes three basic components: a cathode, an anode, and an electrolyte membrane. The cathode and anode typically include a finely divided catalyst, such as platinum, supported on carbon particles and mixed with an ionomer. The electrolyte membrane is sandwiched between the cathode and the anode to form a membrane-electrolyte-assembly (MEA).
In a typical PEM-type fuel cell, the MEA is sandwiched between diffusion media or diffusion layers that are formed from a resilient, conductive, and gas permeable material such as carbon fabric or paper. In certain designs, the cathode and the anode are also formed on the diffusion media and sandwich the electrolyte membrane. The diffusion media serve as current collectors for the anode and cathode as well as provide mechanical support for the MEA. The diffusion media and MEA are pressed between a pair of electronically conductive bipolar plates which also serve as current collectors for collecting the current from the electrochemical fuel cell reaction.
The bipolar plate typically includes two thin, facing metal unipolar plates. One of the metal unipolar plates is an anode plate that defines a flow path on one outer surface thereof for delivery of hydrogen reactant to the anode of the MEA. An outer surface of the other unipolar plate, known as a cathode plate, defines a flow path for the oxidant reactant for delivery to the cathode side of the MEA. When the unipolar plates are joined, the joined surfaces define a path for a coolant fluid to flow therethrough.
The unipolar plates are typically produced from a formable metal that provides suitable strength, electrical conductivity, and corrosion resistance. In particular, stamped thin metallic sheets are typically used for the anode and cathode unipolar plates when forming the bipolar plate. For example, the metallic sheet may be less than about 100 micron in thickness. However, the thin material and high strength of the stainless steel material cause significant lateral (in-plane) spring back. It has been shown that the spring back can reach over 400-500 micron. The spring back causes an uneven distribution of a flow field stamped in the plate assembly, undesirably affecting a functionality of the resulting bipolar plate and fuel cell stack.
As shown in FIG. 1, the large spring back in the bipolar plate 100 may far exceed typical tolerances. The large spring back, if not sufficiently compensated for in a tool used to form the bipolar plate 100, may cause an interference 102 between cathode and anode unipolar plates 104, 106 during assembly of the bipolar plate 100.
To compensate for the lateral bipolar plate spring back, a method of using either global or local morphing to design and cut dies for stamping the bipolar can be used. However, for relatively large spring back (compared to feature size and design tolerance), for example, over 200 microns, the one step methods can undesirably cause severe surface distortion when trying to achieve necessary fidelity due to the large surface deformation.
There is a continuing need for a method providing stable and reliable surface compensation with high accuracy and surface quality for large lateral spring back of fuel cell bipolar plates, to consistently meet the requirements of manufacturing and assembly.

Method to improve the dimensional accuracy and surface quality for large spring back compensation for fuel cell bipolar plate forming


A container including a side wall having a hollow interior, an outwardly extending flange positioned above an upper end of the side wall, a lower end of the side wall having a first wall positioned thereon, a second wall extending upwardly from the first wall into the hollow interior of the side wall, a third wall extending inwardly and downwardly from the second wall, and a base extending inwardly from the third wall. A method of thermoforming the beverage container using a thermoforming operation is also provided.

The present application generally relates to the field of single serve beverage containers. In recent years, there has been a trend to provide consumers with a beverage dispenser that utilizes single serve beverage containers. For example, coffee makers have been developed in which a consumer selects a desired beverage such as coffee, tea, or cocoa which is contained in a pod or capsule. The pod or capsule may contain coffee grounds, tea leaves, or cocoa powder as examples. The pod is placed in a beverage dispenser, and is pierced with a sharp implement and hot water flows through the pod or capsule mixing with the contents of the pod to brew a selected beverage.
Typically, such pods or capsules are made of a plastic material that includes polystyrene, and the pods or capsules are hollow and contain the desired beverage therein. When the pod or capsule is pierced to allow for a flow of hot water therethrough, the pod or capsule undergoes forces which may cause the pod or capsule to crumple or compress, which may result in undesirable cracks in the wall thereof allowing coffee grounds or other contents to seep through the wall of the pod or capsule into a cup positioned on the beverage dispenser beneath the pod or capsule. Therefore, the material used to make the pod or capsule needs to be strong enough to withstand the forces experienced during the piercing process so that it does not get damaged and crack under the forces.
The pods or capsules have heretofore typically been made with a plastic that includes polystyrene, resulting in a pod or capsule which is generally not easily recyclable. As the prevalence of single serve beverage containers has increased, environmental concerns regarding the landfilling of the used pods or capsules has increased as well. In an effort to produce a more environmentally friendly pod or capsule, efforts have been made to provide a pod or capsule that is more easily recycled. Polypropylene may provide a material that may be used to replace polystyrene-containing plastics. However, polypropylene is not as rigid as polystyrene and is more susceptible to being damaged during the piercing process.
In view of the foregoing, it would be desirable to provide a single serve pod or capsule that could be made of, or contain, polypropylene to provide a more easily recyclable pod or capsule. In addition, it would be desirable to provide a single serve pod or capsule that could be made of or contain polypropylene or other rigid plastic that can be formed using a thermoforming process and includes a configuration that achieves a desired strength and rigidity to withstand the piercing process.


Disclosed is a process for preparing 7-(1-hydroxethyl)-3-(2-aminoethylthio)-1-carbadethiaceph-3-em-3-carboxylic acid and its pharmaceutically acceptable salts and esters (I) by total synthesis starting with L-aspartic acid and proceeding via intermediate II: ##STR1## R=blocking group

This invention relates to a process for preparing 7-(1-hydroxyethyl)-3-(2-aminoethylthio)-1-carbadethiaceph-3-em-3-carboxyli c acid and its pharmaceutically acceptable salts and esters (I) which are useful as antibiotics: ##STR2## The compound of Structure I might for convenience be called "homothienamycin" on reference to the known antibiotic thienamycin III: ##STR3## Homothienamycin (I) is disclosed and claimed in co-pending, commonly assigned U.S. Patent Application Ser. No. 903,455 (filed May 8, 1978) now U.S. Pat. No. 4,150,156 issued Apr. 17, 1979 which is incorporated herein by reference to the extent that it describes I and its utility as an antibiotic. Also incorporated by reference is U.S. Pat. No. 3,950,357 which discloses and claims thienamycin; this patent is incorporated by reference to the extent that it teaches the utility of antibiotics such as III and by analogy I.
The process of the present invention is a total synthesis, starting with L-aspartic acid and proceeding in a stereo-selective manner via intermediate II. ##STR4## wherein R is a conventional protecting group. The details of the total synthesis are given below.

Process for preparing 7-(1-hydroxyethyl)-3-(2-aminoethylthio)-1-carbadethiaceph-3-em-3-carboxy lic acid and intermediate therefor


A rear substrate in a plasma display panel including a first substrate through which an image is transmitted to a viewer, and the rear substrate arranged in facing relation to the first substrate, includes (a) an electrically insulating substrate, (b) a plurality of data electrodes arranged on the substrate and spaced away from one another, (c) a plurality of partition walls formed on the substrate, and (d) a phosphor layer covering the substrate and the data electrodes therewith between adjacent partition walls, wherein at least one partition wall and another partition wall among the partition walls are joined to each other at at least one of opposite ends thereof in a length-wise direction through a curved partition wall, the another partition wall extending in the same direction as a direction in which the at least one partition wall extends.

1. Field of the Invention
The invention relates to a plasma display panel, and more particularly to a plasma display panel which is capable of preventing display defectiveness caused by breakage and/or defective shape of partition walls.
2. Description of the Related Art
A plasma display panel is recently often used as a flat display, because a plasma display panel has advantages that it is thin and can be readily applied to a big screen, it has a broad viewing angle, and it has a high response speed.
FIG. 1 is a perspective view of a display cell in a conventional three-electrode surface-discharge AC type plasma display panel.
As illustrated in FIG. 1, a front substrate 351 and a rear substrate 352 are arranged parallel to each other in a display cell.
The front substrate 351 is comprised of an electrically insulating substrate 302 composed of transparent material such as glass, a plurality of scanning electrodes 303 (only one of them is illustrated in FIG. 1) formed on the substrate 302 in facing relation to the rear substrate 352, a plurality of common electrodes 304 (only one of them is illustrated in FIG. 1) formed on the substrate 302 in facing relation to the rear substrate 352, a plurality of trace electrodes 305 each formed on each of the scanning electrodes 303, a plurality of trace electrodes 306 each formed on each of the common electrodes 304, a dielectric layer 312 formed on the substrate 302, covering the scanning electrodes 303, the common electrodes 304 and the trace electrodes 305 and 306 therewith, and a protection layer 313 formed on the dielectric layer 312.
The scanning electrodes 303 and the common electrodes 304 are arranged alternately, and equally spaced away from adjacent ones in parallel with one another.
The trace electrodes 305 and 306 reduce an electrical resistance of the scanning electrode 303 and the common electrode 304, respectively.
The protection layer 313 protects the dielectric layer 312 from discharges. The protection layer 313 is composed of magnesium oxide (MgO), for instance.
The rear substrate 352 is comprised of an electrically insulating substrate 301 composed of transparent material such as glass, a plurality of data electrodes 307 formed on the substrate 301 in a direction perpendicular to a direction in which the scanning electrodes 303 and the common electrodes 304 extend, in facing relation to the front substrate 351, a dielectric layer 341 formed on the substrate 301, covering the data electrodes 307 therewith, a partition wall 315 formed on the dielectric layer 314, and a phosphor layer 311 covering an exposed surface of the dielectric layer 314 and sidewalls of the partition wall 315 therewith.
The substrate 301 in the rear substrate 352 is comprised of a transparent substrate in the display cell illustrated in FIG. 1, however, it is not always necessary for the substrate 301 to be a transparent substrate.
The partition wall 315 defines a discharge gas space and a plurality of display cells (pixels) 308.
Viewing perpendicularly to a surface of the substrate 301, the partition wall 315 is grid-shaped. Specifically, the partition wall 315 is comprised of a vertical partition wall 315a extending in parallel with the data electrodes 317, and a horizontal partition wall 315b extending perpendicularly to the vertical partition wall 315a.
The vertical and horizontal partition walls 315a and 315b are almost equal in height to each other. A height from a surface of the substrate 301 to a summit of the partition wall 315, that is, a total thickness of the dielectric layer 314 and the partition wall 315 is 120 micrometers, for instance.
Each of the display cells 308 is filled with discharge gas composed of noble gas such as helium, neon or xenon singly or in combination.
The phosphor layer 311 receives ultra-violet rays generated due to discharges of discharge gas, and thus, emits a visible light 310.
An area between the front substrate 351 and the rear substrate 352 is comprised of a centrally located display area in which images are displayed, and a non-display area located around the display area. A partition wall formed in a non-display area is called a dummy partition wall, which assists a partition wall to be uniformly formed in a display area during fabrication of a plasma display panel, and prevents contaminants from entering a display area for protection of a display area after fabrication of a plasma display panel. A dummy partition wall is formed generally by one or two rows.
FIGS. 2A to 4B show respective step in a method of fabricating the conventional plasma display panel illustrated in FIG. 1. FIGS. 2A, 3A and 4A are plan views of the rear substrate 352, and FIGS. 2B, 3B and 4B are cross-sectional views taken along the lines 2B, 3B and 4B in FIGS. 2A, 3A and 4A, respectively.
Hereinbelow is explained a method of fabricating the conventional plasma display panel with reference to FIGS. 2A to 4B.
With reference to FIG. 1, the scanning electrodes 303 and the common electrodes 304 are formed on the substrate 302 such that they are alternately arranged and extend in parallel with each other.
Then, the trace electrodes 305 and 306 are formed on the scanning and common electrodes 303 and 304, respectively.
Then, the dielectric layer 312 is formed on the substrate 302 such that the dielectric layer 312 covers the scanning and common electrodes 303 and 304 and the trace electrodes 305 and 306 therewith.
Then, the protection layer 313 composed of MgO is formed on the dielectric layer 312.
Thus, there is fabricated the front substrate 351.
With reference to FIGS. 2A and 2B, a plurality of the data electrodes 307 is formed on the substrate 301.
Then, as illustrated in FIGS. 3A and 3B, the dielectric layer 314 is formed on the substrate 301 such that the dielectric layer 314 covers the data electrodes 307 therewith.
Then, as illustrated in FIGS. 4A and 4B, the partition wall 315 is formed on the dielectric layer 314.
The partition wall 315 can be formed by sand blasting or printing, for instance. The partition wall 315 is formed as follows in the case that the partition wall 315 is formed by sand blasting.
First, filler, glass powder, binder and solvent are mixed to thereby have partition wall paste.
Then, the partition wall paste is coated on the dielectric layer 314. Then, the solvent in the paste is evaporated to thereby form a partition wall paste layer (not illustrated).
Then, a dry film (not illustrated) is adhered onto a surface of the partition wall paste layer, and then, the dry film is patterned.
Then, sand blasting is carried out to the partition wall paste layer with the patterned dry film being used as a mask. As a result, a portion of the partition wall paste layer not covered with the dry film is selectively removed.
Then, the dry film is removed, and the partition wall paste layer is baked. As a result, the binder in the partition wall paste layer is evaporated, and the glass powder is fused and re-cured. Thus, there is formed the partition wall 315 composed of filler and glass.
The partition wall 315 is formed in a grid such that the vertical and horizontal partition walls 315a and 315b are almost equal in height to each other.
Then, as illustrated in FIG. 1, the phosphor layer 311 is formed on an exposed surface of the dielectric layer 314 and sidewalls of the partition wall 315.
Then, the substrates 301 and 302 are aligned with each other such that the protection layer 313 makes contact with the partition wall 315 and that the data electrodes 307 extend perpendicularly to the scanning and common electrodes 303 and 304.
Then, the substrates 301 and 302 aligned with each other are thermally annealed, resulting in that the substrates 301 and 302 are fused at their ends to each other through flits. Thus, a space surrounded by a sealing layer (not illustrated) comprised of the substrates 301 and 302 and the flits is gas-tightly sealed.
Then, the space is exhausted, and thereafter, discharge gas is introduced into the space.
Thus, there is completed the plasma display panel illustrated in FIG. 1.
However, the above-mentioned conventional plasma display panel is accompanied with a problem of poor quality in displaying images which is caused by contraction of a partition wall paste layer generated during being baked. Hereinbelow is explained the problem of contraction of a partition wall paste layer.
The above-mentioned poor quality in displaying images is grouped into two types.
The first type poor quality is caused by that the vertical partition wall 315a is partially raised during the partition wall paste layer is being baked. The first type poor quality is caused because the vertical partition wall 315a is longer and thinner than the horizontal partition wall 315b.
Since the vertical partition wall 315a is longer and thinner than the horizontal partition wall 315b, the vertical partition wall 315a and the horizontal partition wall 315b are different from each other with respect to contraction generated during the partition wall 315 is being baked, and hence, the vertical partition wall 315a is partially raised to thereby become higher than the horizontal partition wall 315b.
As a result, when the substrates 301 and 302 are aligned to each other, a raised portion of the vertical partition wall 315a is compressed by the protection layer 313, and resultingly, the vertical partition wall 315a is often broken. If the vertical partition wall 315a is broken, a portion of the phosphor layer 311 formed on the vertical partition wall 315a itself and sidewalls of the vertical partition wall 315a is scattered into the display cell 308, and resultingly, adheres to the scanning electrode 303 and/or the common electrode 304. This results in that the display cell 308 does not properly operate, that is, the display cell 308 is kept to emit a light regardless of a drive signal or does not emit a light at all.
The second type poor quality is caused by that the vertical and horizontal partition walls 315a and 315b are contracted during the partition wall 315 is being baked, and resultingly, opposite ends of the vertical and horizontal partition walls 315a and 315b in a length-wise direction are deformed to be higher than centers of them.
FIG. 5A is a cross-sectional view illustrating the partition wall 315 before baked, FIG. 5B is a cross-sectional view illustrating the partition wall 315 after baked, and FIG. 5C is a cross-sectional view illustrating the substrates 301 and 302 aligned to each other. For simplification, parts other than the substrates 301 and 302 and the partition wall 315 are omitted in FIGS. 5A to 5C.
As illustrated in FIG. 5A, the partition wall 315 before baked has a uniform height.
However, as illustrated in FIG. 5B, the partition wall 315 is contracted during being baked, and resultingly, opposite ends 315c are raised relative to a central portion 315d.
As illustrated in FIG. 5C, the substrates 301 and 302 are aligned to each other, and then, a discharge gas space is exhausted. The substrates 301 and 302 are bent due to atmospheric pressure. However, the substrates 301 and 302 are bent in a different curvature from the partition wall 315, and accordingly, gaps 316 are formed between the partition wall 315 and the substrate 302 in the vicinity of the ends 315c.
As a result, a display cell 308 including the gaps 316 would have an increased volume, and hence, a voltage necessary for generating writing discharge in the display cell 308 would be raised. Thus, writing discharge would not be generated by an ordinary drive voltage in the display cell 308, resulting in writing defectiveness. Thus, the plasma display panel would have a problem of display defectiveness.
There have been suggested solutions to the second type poor quality.
For instance, Japanese Patent Application Publication No. 2001-319580 has suggested a plasma display panel in which a dielectric layer is not formed in a non-display area on a rear substrate, and a partition wall is formed directly on the rear substrate in order to prevent the above-mentioned second type poor quality. This ensures that a partition wall located in a non-display area is lower in height than a partition wall located in a display area. Hence, even if a partition wall is contracted, and accordingly, opposite ends thereof in a length-wise direction become higher than a central area, it would be possible to prevent formation of gaps between the partition wall and a front substrate.
In contrast to the second type poor quality, the first type poor quality is not well recognized, and accordingly, solutions are not much suggested.
For instance, the plasma display panel suggested in the above-mentioned Japanese Patent Application Publication No. 2001-319580 prevents the second type poor quality, but cannot prevent the first type poor quality.
Japanese Patent Application Publication No. 2000-340123 has suggested a plasma display panel which includes an improved horizontal partition wall in order to prevent the first type poor quality.
FIG. 6 is a plan view of a partition wall in the plasma display panel suggested in Japanese Patent Application Publication No. 2000-340123.
As illustrated in FIG. 6, the partition wall is comprised of a plurality of horizontal partition walls 315A horizontally extending, and a plurality of vertical partition walls 315B extending vertically only between adjacent horizontal partition walls 315A.
Each of the horizontal partition walls 315A is designed to have extensions 315C extending from opposite ends thereof Even if the horizontal partition walls 315A is raised at its opposite ends due to the contraction, such a raise is concentrated to the extensions 315C. Front and rear substrates are joined to each other between the extensions 315C formed at opposite ends of the horizontal partition wall 315A. Accordingly, front and rear substrates can be joined to each other with a constant gap being kept therebetween without being influenced by the raised extensions 315C.
Japanese Patent Application Publication No. 11-339668 has suggested a plasma display panel including a partition wall having opposite tapered ends 315D, as illustrated in FIG. 7, to prevent formation of a raise portion caused by contraction.
The plasma display panel suggested in Japanese Patent Application Publication No. 2000-340123 makes it possible for front and rear substrates to join to each other with a constant gap being kept therebetween. However, since the extensions 315C are raised, if the front and rear substrates are misaligned even slightly, the front substrate aligns with the raised extensions 315C, resulting in that it would not be possible to keep a constant gap between the front and rear substrates.
Accordingly, it is necessary to align the front and rear substrates to each other highly accurately before they join to each other. This causes an additional problem that steps of fabricating a plasma display panel are unavoidably complicated.
The partition wall suggested in Japanese Patent Application Publication No. 11-339668 is formed by physically grinding, punching or a process of half-exposing a partition wall to a light.
If the tapered ends 315D are formed by grinding, there are newly caused problems that a grinding step has to be additionally carried out, and chips are generated in a grinding step.
If the tapered ends 315D are formed by punching or half-exposing process, there are newly caused problems that an equipment for doing so has to be newly prepared, and hence, punching or half-exposing process cannot be applied to a conventional method of forming a partition wall by sand blasting.

Plasma display panel with curved partition wall


An object of the present invention is to further improve electric characteristics such as ON-resistance or an ON-breakdown voltage in a semiconductor device having a lateral MOS transistor.

The present invention relates to a semiconductor device and a manufacturing method thereof, and can be preferably used in a semiconductor device having, for example, an LDMOSFET.
A semiconductor device having an LDMOSFET (Laterally Diffused Metal-Oxide-Semiconductor Field Effect Transistor: hereinafter, referred to as a "lateral MOS transistor") is one of those for electric power for which high pressure resistance is required. For example, in a semiconductor device disclosed in Japanese Unexamined Patent Application Publication No. 2006-108208, an electric field control electrode is formed on a part of a field oxide film located between a gate electrode and a drain electrode. A voltage controlled independently from the gate electrode is applied to the electric field control electrode. An electron accumulation layer is formed at the interface between the field oxide film and an N-well diffusion layer by applying a high voltage to the electric field control electrode. Accordingly, ON-resistance can be reduced.
Further, in a semiconductor device disclosed in Japanese Unexamined Patent Application Publication No. 2014-107302, a p-type drift region and an insulating region are formed between a channel formation region and a drain region. A gate electrode is formed so as to extend from the channel formation region to the insulating region by interposing a gate insulating film while having an opening exposing the interface part between the channel formation region and the insulating region, and the reliability of the gate insulating film can be improved by forming the opening at the gate electrode.
Further, in a semiconductor device disclosed in Japanese Unexamined Patent Application Publication No. 2009-278100, an orthogonal gate electrode having a gate electrode folded into an STI (Shallow Trench Isolation) oxide film region is formed. The orthogonal gate electrode reduces a capacity overlapped between a gate and a drain, and the switching time can be made faster.

Semiconductor device having a buried electrode and manufacturing method thereof

Abstract: In a semiconductor device having a lateral MOS transistor, a buried electrode is formed at a part of an isolation insulating film located between a drain region and a gate electrode. The buried electrode includes a buried part. The buried part is formed from the surface of the isolation insulating film up to a depth corresponding to a thickness thinner than that of the isolation insulating film. The buried electrode is electrically coupled to the drain region.


A dust collecting device of a vacuum cleaner includes a first cyclone unit comprising a first cyclone chamber where the air enters through a first inlet and spins, and a first dust collecting chamber where dust separated from the air is collected; and a second cyclone unit comprising a second cyclone chamber where the air, discharged from the first cyclone unit, enters through a second inlet and spins, and one or more dust collecting parts formed on a circumference of a second cyclone body to separate minute dust from the air upon contacting with the air spinning within the second cyclone chamber. Accordingly, efficiency in collecting minute dust by the dust collecting device increases.

1. Field of the Invention
The present invention relates to a vacuum cleaner. More particularly, the present invention relates to a dust collecting device of a vacuum cleaner, which separates dust from externally-drawn air and accommodates the separated dust therein.
2. Description of the Related Art
General operation of a vacuum cleaner includes drawing in external air and dust, and separating the dust from the drawn air. The vacuum cleaner employs a dust collecting device to separate the dust and accommodate the separated dust. A cyclone dust collector, which separates dusts from the air by using centrifugal force, is quite popular among the dust collecting devices. Unlike the existing dust bags, the cyclone dust collector can be used repeatedly, and it provides more hygienic environment.
Although a cyclone dust collector is effective in separating large particles of dust from the air, the structural limit of the cyclone dust collector generates a problem of re-scattering and discharging of usually small particles of the collected dust to the outside.
A filter for fine dust has been used in a vacuum cleaner to prevent the above problem by re-filtering air and blocking fine particles of dust. However, as the vacuum cleaner additionally employs the filter for fine dust, structure is complicated, and because users have to use the filter as a separate part from the cyclone dust collector, maintenance of the vacuum cleaner is inconvenient.

Dust collecting device for vacuum cleaner


An apparatus includes a gasket and a housing assembly. The gasket may have (i) a base portion, (ii) a column portion and (iii) a passage in communication with an exterior of the apparatus. The housing assembly may have a sealing edge and may be configured to hold a sensor. The sealing edge may seal to the base portion of the gasket. The sensor (a) may seal to the column portion of the gasket and (b) may be in communication with the exterior of the apparatus through the passage.

Pressure sensors conventionally operate in moisture-rich environments and therefore are sealed inside a housing. To accomplish the sealing, a gasket is commonly used with the sensor to control the environment to which the sensor is exposed. However, leaks around the gasket cause problems for the sensor measurements and communication.
It would be desirable to implement a pressure sensor unit with a rectangular gasket.

Pressure sensor unit with rectangular gasket


A silver halide color photographic light-sensitive material is disclosed which comprises a support having thereon, in any order, at least one yellow generating light-sensitive silver halide emulsion layer, at least one magenta generating light-sensitive silver halide emulsion layer, and at least one cyan generating light-sensitive silver halide emulsion layer, wherein at least one of the magenta generating light-sensitive silver halide emulsion layer contains at least one dye-forming coupler represented by a specific formula (M-I), and at least one of the yellow generating light-sensitive silver halide emulsion layer contains at least one dye-forming coupler represented by a specific forrmula (Y-I). This material can be used, for example, as a material suitable for quick developing material. ##STR1##

1. Field of the Invention
The present invention relates to a silver halide color photographic light-sensitive material, and particularly, to material having an excellent color developable property, a color reproducing property, and an improved finishing stability against variation in the compositions of processing solutions. The present invention also relates to a method for forming color images with such a silver halide color photographic light-sensitive material.
2. Description of the Related Art
In the most common method for forming color images by using a silver halide color photographic light-sensitive material, silver halides are exposed to function as an oxidizing agent, and then an aromatic primary amine color developing agent oxidized by the oxidizing agent and a coupler are reacted to form dyes such as indophenol, indoaniline, indamine, azomethine, phenoxazine, and phenazine. In this method, color images are reproduced by a substrative color process wherein three kinds off dyes for yellow, magenta and cyan are generated In different amounts to form color images.
Conventionally, a 5-pyrazolone coupler has been generally used as a magenta coupler. However, the 5-pyrazolone magenta coupler has a secondary absorbing band in the vicinity of 430 nm. Thus, it has a problem of insufficient color reproduction. To improve color reproduction, pyrazoloazole couplers having an excellent absorbing property have been developed to improve color reproducing properties. For example, the 1H-pyrazolo[5,1-c]-1,2,4-triazole magenta coupler disclosed in U.S. Pat. No. 3,725,067,and the 1H-pyrazolo[1,5-b]-1,2,4-triazole magenta coupler disclosed in JP-B-2-44,051 have excellent absorbing properties. Among them, the 1H-pyrazolo[1,5-b]-1,2,4-triazole magenta is excellent in a color developable property, and fastness of dye images, as well. Especially, couplers wherein a branched alkyl group is introduced into a pyrazolotriazole ring, as described in JP-A-61-65,245 and U.S. Pat. No. 4,882,266, are couplers having improved stability against variable factors in processing, and improved fastness of color images. However, the couplers still have a problem of an unsatisfactory color developable property. The 1H-pyrazolo[1,5-b]-1,2,4-triazole magenta coupler having both of a branched alkyl group at 6- position and a phenyl group at 2- position, which is described in EP-0,571,959 A2,is an excellent coupler having an improved color developable property. However, this coupler has a drawback that, especially when subjected to a quick processing, a tint of magenta is migrated into yellow images, resulting in increased color amalgamation.
Meanwhile, as yellow couplers, a pivaloyl coupler and a benzoyl coupler have been conventionally used. Although the pivaloyl coupler provides excellent image fastness, it has the problems that the molecular extinction coefficient of generated dye molecules is small and that it has low activity as a coupler. Accordingly, a larger amount of the coupler must be used,and thus problem of cost occurs. Also, it is difficult to make a yellow color developable layer thinner. Thus, quicker processing, and reduction of replenishing liquids cannot be achieved.
To increase the extinction coefficient of a dye molecule to be generated, an acylacetoanilide coupler having a cyclic acyl group having 3-5 members (EP-0,447,969 A1), and a marondianilide coupler having a cyclic structure (EP-0,482, 552 A1) have been proposed. Also, many attempts have been made to increase activity of couplers. One of the attempts is to increase activity of a coupler by increasing hydrophilicity of the coupler. For example, JP-A-50-132,926, JP-A-62-206,549, and JP-A-63-291,056 disclose couplers into which oxazolidine-2,4-dione-3-yl, or 1,2,4-triazolidine-3,5-dione-4-yl is introduced as a removable group. Also, JP-A-3-126,939, JP-A-3-126,940, and JP-A-3-126,941 disclose couplers into which imidazolidine-2,4-dion-3-yl is introduced. Meanwhile, studies have been made of yellow couplers to improve an absorption property of generated dyes so as to improve a color reproducing property. The above-mentioned acylacetoanilide coupler having a cyclic acyl group having 3-5 members and the marondianilide coupler having a cyclic configuration are also excellent in the absorption property of dyes. To improve the hue of pivaloyl couplers, the methods have been proposed in which a specific group such as an alkoxy group is introduced into the ortho-position of an anilide ring, as described in JP-A-52-115,219 and JP-A-63-123,047. Also, it has been attempted to improve the color developable property of those couplers, as described in JP-A-3-125,140,JP-A-3-125,141, and JP-A-6-11,808. The color developable property can be improved by increasing hydrohilicity. However, it will increase interaction with a silver halide emulsion agent. Thus, when the light-sensitive material is used after storage for a long period of time, or it is processed with processing solutions whose compositions have been varied, fogging and variation in the gradation occur, bringing new problems. Also, the degree of color amalgamation (wherein a tint of yellow is introduced into magenta images) during processing increases depending on the types of magenta couplers. Especially, when the processing temperature, the concentration of a developing agent and/or pH of a color developing solution is increased, and/or the layers of a light-sensitive material is made thinner for quicker processing, the above-described problems become more serious.

Silver halide color photographic light-sensitive material


Disclosed is a scanning apparatus used in, for example, a facsimile copying device. A scanning mechanism carries out a time sequential scanning of a manuscript sheet by, for example, a laser. A photoelectric element holding block, having a slit for allowing the passage of scanning beams from the scanning mechanism, travels jointly with the time sequence scanning of the manuscript sheet. A plurality of photoelectric elements are set around the slit of the holding block.

This invention relates to a scanning apparatus which carries out time sequence scanning and photoelectrically converts the resultant optical data into electric signals.
A large number of processes are already known for scanning optical data impressed on the surface of a manuscript sheet such as a single paper sheet or the respective pages of a book by light beams, for example, laser beams and photoelectrically converting the resultant reflections into electric signals. Since, in this case, the central portion of the manuscript sheet is positioned remotest from the surrounding photoelectric conversion elements, problems have been raised due to an undesirable phenomenon generally referred to as "shading" appearing in the central portion of the manuscript sheet. This shading phenomenon becomes noticeable particularly when the manuscript sheet has a large size.


A number of capacitive pixels formed in an electroluminescent display panel are selectively charged and discharged by the driving device. The driving device is composed of a charging circuit connected between a power source and the pixels and a discharging circuit connected between the pixels and the ground. Both the charging and discharging circuits include a respective inductive coil that constitutes a series L-C circuit together with the capacitive pixel. Since the pixels are charged and discharged through the series L-C circuit, impulse current otherwise flows in and out of the pixels is suppressed, and thereby radio noises generated by the impulse current are prevented.

This application is based upon and claims benefit of priority of Japanese Patent Application No. Hei-11-105640 filed on Apr. 13, 1999, the content of which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to a device for driving a capacitive load such as an electroluminescent panel.
2. Description of Related Art
A circuit for driving an electroluminescent panel is disclosed in JP-A-9-305144. This driving circuit includes a circuit for controlling a charging and discharging current of capacitive electroluminescent elements at a constant level (this circuit is referred to as a constant-current circuit). The constant-current circuit prevents an impulse current otherwise supplied to the electroluminescent elements. More particularly, as shown in FIG. 9A attached to this specification, the driving circuit includes a charging circuit 1 and a discharging circuit 2. When an FET 1a (a field effect transistor) in the charging circuit 1 turns on according to a control signal-1 fed through a coupling condenser 1c and an inverter 1d, an electroluminescent element 3 is charged with a voltage VH+ through a resistor 1b and the FET 1a. On the other hand, when an EFT 2a in the discharging circuit 2 is turned on according to a control signal-2 fed through a coupling condenser 2c, the electroluminescent element 3 is discharged through the FET 2a/and a resistor 2b.
As shown in FIG. 9B, the charging current Iel in the above-described circuit abruptly rises upon turning-on of the EFT 1a, and the discharging current Iel abruptly flows upon turning-on of the FET 2a. A terminal voltage of the electroluminescent element 3 linearly rises up to the voltage level of VH+, the linearly drops down to the level of 0 volt. This means an impulse current flows upon turning-on of the FETS 1a and 2a. The impulse current generates radio noises though the constant-current circuit controls the charging and discharging current at a constant level after it reaches that level. If the resistors 1b and 2b are eliminated as shown in FIG. 10A, the charging and discharging current change further abruptly as shown in FIG. 10B. Accordingly, further higher radio noises are generated by the impulse current.
To cope with the problem described above, JP-A-2-256191 (the counter part: U.S. Pat. No. 5,027,040) proposes to insert a coil between the FET 1a and the electroluminescent element 3 and another coil between the FET 2a and the electroluminescent element 3. Since the coils alleviate sharp rising-up of the impulse current, the radio noises will be reduced. However, coils having large inductance are required to reduce the radio noises in the proposed manner for the following reason. A frequency fel for driving the electroluminescent element in the circuit shown in the above JP-A-2-256191 is determined according to the following formula: fel(Hz)=1/{4xcfx80(LCel)xc2xd}, where L is an inductance of the inserted coil, and Cel, is a capacitance of the electroluminescent element. If Cel is 2 (nF), and fel is 400 (Hz), L has to be in the order of 20 (H) to effectively suppress the impulse current. It is, however, difficult to buy such a coil having a large inductance, because such a coil is not available in the usual market.
The present invention has been made in view of the above-mentioned problem, and an object of the present invention is to provide an improved device for driving a capacitive load such as an electroluminescent panel, in which radio noises are effectively suppressed without using coils having a large inductance.
A driving device of the present invention alternately charges and discharges a capacitive load. The driving device is composed of a charging circuit connected between a power source and the capacitive load and a discharging circuit connected between the capacitive load and a ground. The charging circuit is a series circuit including an inductive coil and a transistor that is turned on or off according to a control signal fed thereto. The charging circuit constitutes a series L-C circuit together with the capacitive load. The discharging circuit is a similar series circuit including an inductive coil and a transistor that is turned on or off according to another control signal fed thereto. The discharging circuit also constitutes a series L-C circuit together with the capacitive load.
The capacitive load is charged through the charging circuit upon closing the charging circuit, while it is discharged through the discharging circuit. An impulse current that otherwise flows into the capacitive load upon turning-on of the transistor in the charging circuit is suppressed by the inductive coil. Similarly, an impulse current otherwise flowing out of the capacitive load upon turning-on of the transistor in the discharging circuit is suppressed by the inductive coil. Since the impulse current flowing in and flowing out of the capacitive load is suppressed, radio noises generated by the impulse current are prevented. A resistor may be additionally inserted in both the charging and discharging circuits thereby to limit the charging and discharging current to a constant level, while suppressing the impulse current by the inductive coil.
An electroluminescent display panel having capacitive pixels may be driven by the driving device of the present invention. The electroluminescent panel is composed of an array of scanning electrodes, an array of data electrodes and electroluminescent layer interposed between both arrays. Pixels are formed at each inter section of both electrodes, and they are alternately charged and discharged by the driving device to selectively activate the pixels. Since the pixels are capacitive elements, they are driven by the driving device of the present invention in the same manner as other inductive loads. The impulse current in charging and discharging is suppressed, and thereby radio noises are prevented.
A diode may be connected in parallel to the inductive coil in the charging circuit to limit a level of the charging voltage imposed on the capacitive load. To supply scanning voltages sequentially and selectively to the scanning electrodes of the electroluminescent panel a thyristor may be connected between the driving device and each scanning electrode.


A position sensing apparatus and method, motion control system, and integrated circuit are provided that include a plurality of sensors and a tracking processor. The plurality of sensors includes a linear array of sensors that sense a plurality of features of an object. A spacing between two of the plurality of sensors is substantially smaller than a spacing between two of the plurality of features. The tracking processor samples signals from the sensors, compares the samples to previous samples and calculates a position of the object. The plurality of sensors may include a second linear array of sensors. Centers of the sensors of the second linear array may be offset from centers of the sensors of the first linear array along a longitudinal axis of the plurality of sensors.

Many applications have a need to measure position with high resolution and accuracy, but at a low cost. One example of such an application is paper motion control in inkjet printers. The spacing between nozzles in an inkjet printer is very fine—typically 1/600″ (about 1.6 mils, or 42 microns). In order to prevent visible banding when printing graphic images, the linefeed error must be significantly less than the distance between adjacent nozzles. An inkjet printer typically uses a DC servo system for motion control, with an incremental optical encoder for position feedback.
Typically, position measurement solutions require a trade-off among the factors such as resolution, cost and computing overhead. Low resolution physical components may be used and computing overhead kept low by utilizing additional circuitry, thereby increasing overall system cost. Alternatively, more costly high resolution physical components may be used, obviating the need for additional circuitry while keeping computing overhead low. In yet another solution, low resolution physical components and minimal additional circuitry may be used, resulting in higher computation overhead.
As such, there is a need for an apparatus and method for measuring position with a high resolution and accuracy. In particular, there is a need for position measurement with high resolution and accuracy, at relatively low cost, with minimal computational overhead in a system employing such a measurement apparatus.


A radiant heat reflective composition comprising a blend of a tetrafluoroethylene copolymer and copper flake.

Many polymers are useful as protective shielding for various purposes, such as for abrasion resistance, chemical resistance or heat resistance. The polymers can take the form of a coating, film, or tube, or the like. In such instances, it is frequently beneficial to incorporate additives to enhance specific shielding performance. For example, in Japanese laid-open publication 59-25833 certain flake or platelet additives coated with polyamide acids are incorporated into certain fluorine-containing polymers to enhance abrasion resistance and compression resistance. In addition, aluminum flake is used in various thermoplastics to shield semiconductor components from electromagnetic impulse, as seen by Modern Plastics Encyclopedia 1984-1985, pages 558 and 562.
With the increased use of thermoplastic polymers in high temperature applications such as automotive engine equipment where temperatures reach 125.degree. C. or more, it is desirable to develop thermoplastic polymers having improved shielding, or radiant heat reflectivity.


A pattern forming method comprising: coating a resist composition on a substrate; adjusting a rotational speed of the substrate within a range of 500 to 1,500 rpm so that a film thickness of the resist composition coated is adjusted; and subjecting the resist composition to drying, exposure and development, wherein the resist composition includes: (A) a compound capable of generating an acid upon irradiation with one of actinic rays and radiation; (B) a resin of which dissolution rate in an alkali developer increases under the action of an acid; (C) a mixed solvent; and (D) a surfactant, and the mixed solvent (C) includes at least one member selected from a group A of solvents and at least one member selected from a group B of solvents, or includes at least one member selected from the group A of solvents and at least one member selected from a group C of solvents: Group A: propylene glycol monoalkyl ether carboxylates, Group B: propylene glycol monoalkyl ethers, alkyl lactates, acetic acid esters, one of chain and cyclic ketones, and alkoxyalkyl propionates, and Group C: γ-butyrolactone, ethylene carbonate and propylene carbonate.

1. Field of the Invention
The present invention relates to a pattern forming method for use in the process of producing a semiconductor such as IC, in the production of a circuit board of liquid crystal, thermal head or the like or in other photofabrication processes, and also relates to a resist composition used therefor.
2. Background Art
The gate dimension of a semiconductor is becoming smaller year by year and according to the roadmap published in ITRS (The International Technology Roadmap for Semiconductor), the gate dimension and its dimensional variation in 3-sigma become 25 nm and 2.2 nm, respectively, in 2007. However, techniques known at present cannot achieve these dimensional controls.
In order to enhance the gate dimension uniformity, the dimensional uniformity of the resist pattern used at the gate processing must be enhanced, and enhancement of the dimensional uniformity have been heretofore made by various techniques.
The process of forming a resist pattern on a semiconductor substrate is generally a photolithography process comprising the following steps:
1. a photoresist solution is spin-coated on a semiconductor substrate (wafer),
2. the wafer is baked to remove the excess solvent contained in the coated photoresist layer,
3. the baked wafer is cooled to room temperature,
4. the photoresist layer is irradiated (exposed) with radiation though a mask to obtain a desired resist pattern,
5. the wafer is baked to make uniform the chemical reaction in the photoresist layer,
6. the baked wafer is cooled to room temperature,
7. the wafer is applied with a developer to remove the chemically changed photoresist layer (or chemically unchanged photoresist layer), and
8. the wafer is rinsed with pure water to remove the developer and then dried.
An attempt for enhancing the dimensional uniformity of the resist pattern is being made in each step such as coating, baking and development of the resist.
For example, it is studied to optimize the baking temperature, the temperature distribution of a hot plate on which the baking is performed, and the environment in which the hot plate is placed, or prevent re-adhesion of a volatile component from the resist onto the resist film at the baking.
As for the development step, it is studied to design the method of dropping a developer on the wafer, optimize the composition or temperature of the developer, or enhance the wettability of the resist film surface to the developer. Also, optimization of the concentration of the resist composition in the developer or optimization of the developing apparatus, particularly the shape of a nozzle for supplying a developer onto the wafer or the method of supplying the developer, is being studied.
As for the coating step, it is studied to enhance the dimensional uniformity by uniformly forming a resist film on a substrate. For example, in JP-A-7-320999 (the term "JP-A" as used herein means an "unexamined published Japanese patent application"), JP-A-10-223501, JP-A-2000-82647, JP-A-2000-150352, JP-A-2000-321458, JP-A-2003-136014, JP-A-2003-303757, JP-A-2005-128516, a method for forming a uniform coating film on a wafer is disclosed.
However, sufficiently high dimensional uniformity could not be achieved by these methods.

Pattern forming method and resist composition used therefor


A game apparatus comprising a novel game board and playing accessories is suitable for play by two persons in a short period of time. The game board comprises an elongated board divided into checkered squares of three different colors and having base strips at opposite ends of the board and a neutral strip across the center of the board from side to side. There are positioned at the base strips at opposite ends of the board the playing pieces of each player. The board simulates a space war. The playing pieces are of three distinct types, command ships, cargo ships and fighter ships. Movement of the pieces is first from the base strip onto the playing area of the board, with additional playing pieces being moved into the base strip as spaces are available. Movement of the pieces is determined by three dice having distinctive indicia. One die has the numerals 1, 2 and 3 thereon. A second die has indicia for the three different playing pieces. The third die has indicia for the colors of the board on which movement is permitted (movement is permitted on only two colors) and indicia indicating destruction of an opposing piece and the color of the square where such piece is located. Play continues until the opposing base is occupied or the two opposing command ship pieces are destroyed.

1. Field of the Invention
This invention relates to a new and useful improvements in board games and more particularly to board games involving the movement of playing pieces on a checkered board.
2. Brief Description of the Prior Art
Miller U.S. Pat. No. 1,595,906 discloses a game played on a board having a plurality of peripheral paths and a plurality of radial paths in which the playing pieces, shaped like a checker, are moved according to colored dice.
Haggard et al. U.S. Pat. No. 2,316,862 discloses a war game having a plurality of playing pieces movable between various playing spaces according to preselected rules.
Clark U.S. Pat. No. 3,649,022 discloses a board game having a plurality of paths of playing positions associated with marking of different colors and arranged with major and minor playing pieces movable according to a plurality of special dice.
Liston U.S. Pat. No. 3,709,498 discloses a board game apparatus including special apparatus for programing play.
Patterson U.S. Pat. No. 3,791,648 discloses a board game having a surface made up of circular spaces disposed about the board in 9 files and 12 ranks and playing pieces movable thereon according to the role of certain dice.
Comeaux U.S. Pat. No. 4,046,381 discloses a board game having a plurality of playing spaces arranged in a hierarchy and playing pieces movable according to a coded set of dice.

7245 Fairbanks-North Houston Rd., Box 159


A scanning optical system, includes a mirror unit equipped with a first mirror surface and a second mirror surface each of which inclines to a rotation axis; and a light projecting system which includes at least one light source to emit a light flux toward the first mirror surface. A light flux emitted from the light source is reflected on the first mirror surface of the mirror unit, thereafter, reflected on the second mirror surface, and then, projected so as to scan in a main scanning direction onto an object in accordance with rotation of the mirror unit, and in a case where a direction included in a main scanning plane is set to 0 degree, the light flux reflected on the second mirror surface is polarized in a range within an angle of ±30 degrees to the main scanning plane.

In recent years, in the fields, such as vehicles, security robots, unmanned helicopters, and the like, requests to perform obstacle detection in a proceeding direction accurately for the purpose of collision prevention, have been increasing. As methods of detecting obstacles, a laser radar which is a distance measuring apparatus utilizing optical scanning, has been known. General laser radars are configured to rotate or oscillate a polygon mirror or the like while projecting light fluxes emitted from a laser light source onto a mirror, the polygon mirror, or the like so as to scan a wide range and to receive scattered light rays from a projected object with a light receiving element, thereby performing distance measurement.
PTL 1 discloses a technique with regard to a polygon mirror which includes the even number of planar reflective surfaces and performs scanning by reflecting light rays the even number of times.


An actuation system according to various embodiments can include an actuation ring having a first end and a second end separated by a gap, the actuation ring being configured to be coupled to a blade outer air seal (BOAS). The actuation system can also include an actuator coupled to at least one of the first end or the second end and configured to adjust a size of the gap such that a tip clearance between the BOAS and a blade tip is reduced in response to the size of the gap being reduced.

Gas turbine engines typically include a fan section, a compressor section, a combustor section and a turbine section. The efficiency of the turbine section is affected by tip clearance between a blade tip and a blade outer air seal (BOAS). The BOAS is typically coupled to a case of the gas turbine engine. In response to acceleration of the gas turbine engine, the blade tips can expand outward due to increased heat and centrifugal force at a faster rate than the case expands outward. The tip clearance may be designed to be relatively large due to this rapid expansion of the blade tips relative to the BOAS. Thus, it is desirable to have systems and methods for active tip clearance control.

High response turbine tip clearance control system


Homopolymers or copolymers of acrylates, homopolymers or copolymers of norbornenes, and copolymers of acrylates with norbornenes, may be prepared by contacting acrylate and/or norbornene monomer reactant under polymerization conditions and in the presence of a solvent with a catalyst system consisting essentially of a Pd(II) dimer component having the formula: [(L)Pd(R)(X)]2, where L is a monodentate phosphorus or nitrogen ligand, X is an anionic group, and R is an alkyl or aryl group.

This invention relates to a novel catalyst that is suitable for use in the homopolymerization of norbornenes, in the homopolymerization of acrylates, and in the copolymerization of norbornenes with acrylates. The invention relates, further, to a process for homopolymerizing norbornenes and acrylates using the present catalyst, to a process for copolymerizing norbornenes with acrylates using the present catalyst, and to novel copolymers of norbornenes with acrylates.
Considerable interest has existed in the copolymerization of acrylates with norbornenes because of the potential benefits of combining the useful properties of the homopolymers of the two monomers. For example, polyacrylates are valued for their extreme hardness and adhesive properties, and are used to form clear, glass-like materials such as Lucite(trademark) and Plexiglas(trademark). Polynorbornenes, on the other hand, are capable of resisting high temperatures and, thus, typically are employed in applications that necessitate high-temperature stability.
Polymerization of acrylic derivatives is disclosed, for example, in U.S. Pat. No. 4,849,488. In that patent, certain phosphorus compounds are used as polymerization catalysts. Preferred acrylic derivatives that are polymerized in accordance with that patent are acrylates and methacrylates of monovalent and polyvalent alcohols. Copolymers of at least two different acrylic derivatives are also disclosed. There is no disclosure in that patent relevant to the possibility of copolymerizing an acrylic derivative with norbornene or a norbornene derivative.
Until the present invention, attempts to copolymerize acrylates with norbornenes have met with modest success because of a disparity in the mechanisms by which the respective monomers polymerize. U.S. Pat. No. 3,697,490, for example, discloses copolymers of alkoxy alkyl acrylates, alkyl acrylates and substituted norbornene, wherein the copolymers contain only about 0.5 to about 5.5 percent by weight substituted norbornene compounds. The copolymers described in that patent typically are prepared in batch reactions, or the monomers may be proportioned to a reactor containing water and other desired polymerization additives. The patent indicates that best results are generally obtained at polymerization temperatures in the range of 5xc2x0 C. to 50xc2x0 C. in the presence of water containing a free radical generating catalyst and surface active agents.
U.S. Pat. No. 6,034,259 broadly discloses a process for polymerizing ethylene, acyclic olefins, and/or selected cyclic olefins, and optionally selected olefinic esters or carboxylic acids. The polymerization reactions are catalyzed by selected transition metal compounds, and sometimes other co-catalysts. Also described in that patent is the synthesis of linear alpha-olefins by the oligomerization of ethylene using as a catalyst system a combination of a nickel compound having a selected alpha-diimine ligand and a selected Lewis or Bronsted acid, or by contacting selected alpha-diimine complexes with ethylene. That patent also discloses polymerization of substituted norbornenes using the disclosed alpha-diimine-containing catalysts systems.
Japanese publication JP040063810 relates to copolymers that contain units derived from three essential monomers, namely: (i) an acrylic ester and/or methacrylic ester monomer, (2) a monomer that possesses a norbornene skeleton, and (iii) a monomer that can be radical-polymerized with the monomer that contains the norbornene skeleton. The copolymers must contain from about 0.5 to about 35 mole % of units derived from radical-polymerizable monomer (iii). The compounds that are disclosed as being suitable for use as the monomer (iii) include esters of maleic acid and an aliphatic alcohol which contains from 1 to 12 carbon atoms, maleic anhydride, N-substituted maleimides, xcex1-cyanocinnamic acid, esters of xcex1-cyanocinnamic acid and an aliphatic alcohol which contains from 1 to 12 carbon atoms, and esters of fumaric acid and an aliphatic alcohol which contains from 1 to 12 carbon atoms. The copolymerization reaction that is described in the Japanese publication typically is conducted in the presence of a free radical polymerization initiator, such as acetyl peroxide, benzoyl peroxide, 2,2xe2x80x2-azobiscyclopropylpropionitrile, or the like.
Typically, acrylates polymerize in the presence of radical or anionic initiators, whereas norbornenes do not follow radical pathways and normally are polymerized by cationic or insertion mechanisms. Therefore, in order to affect the copolymerization of acrylates with norbornenes, it was necessary to develop a catalyst system that would be effective for polymerizing both types of monomers.
It is an object of the present invention to provide a catalyst system that is capable of copolymerizing acrylates with norbornenes.
It is another object to provide a catalyst system that is useful for the homopolymerization of both acrylate monomers and norbornenes.
It is yet another object to provide a novel catalyst system that is useful both for the homopolymerizing of acrylate monomers and norbornene monomers, and for the copolymerization of acrylates with norbornenes.
Still another object of the invention is to provide novel copolymers of acrylates with norbornenes.
The above and other objects and advantages of the invention are accomplished in one embodiment by providing a Pd(II)-based catalyst system which homopolymerizes acrylates to high molecular weight polymers, which homopolymerizes norbornenes to polymers, and which copolymerizes acrylates with norbornenes to high molecular weight polymers. The copolymers prepared in accordance with this invention are characterized by advantages and properties attributable to the respective acrylate and norbornene monomers from which they are derived. The copolymers can be tailored in norbornene to acrylate ratio by varying the ratio of the respective monomers in the reaction mixture and by varying the ligands utilized in the catalyst system.
The copolymers can be prepared simply by reacting one or more acrylate monomers with one or more norbornene monomers in the presence of the present Pd(II)-based catalyst system. The acrylate and norbornene monomers are the only essential monomers, although additional monomers may be added to the polymerization mixture, provided that they do not interfere with the desired polymerization. Thus, while there may be some instances where it would be desirable to add monomers that can be radical-polymerized with the norbornene monomer, such as the monomers described above in connection Japanese publication JP040063810 as radical-polymerizable monomer (iii), it is preferred to prepare the copolymers of the present invention in the absence of such added monomers.
As used in this specification and claims, the terms xe2x80x9cacrylatesxe2x80x9d is meant to include compounds of the general formula H2Cxe2x95x90CHCOOR, where R is an alkyl group, such as methyl (CH3), ethyl (CH2CH3), propyl (CH2CH2CH3), n-butyl (CH2CH2CH2CH3) or t-butyl (Cxe2x80x94(CH3)3), or an aryl group, such as phenyl (C6H6) or p-tolyl (C7H8). Other acrylates which do not conform to the above formula, but which are nonetheless suitable for use in the present invention and are intended to be included within the scope of the term xe2x80x9cacrylatesxe2x80x9d, include such acrylates as 2-hydroxy ethyl methacrylate and methyl methacrylate. Specific, non-limiting examples of acrylates contemplated for use in the present invention include methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, t-butyl acrylate, acrylamide, 2-hydroxy ethyl methacrylate, methyl methacrylate, acrolein, ethyl methacrylate, acryloyl chloride and phenyl acrylate.
The term xe2x80x9cnorbornenesxe2x80x9d is meant to include norbornene, as well as norbornene derivatives, such as norbomadiene and compounds conforming to the general formulas 5-norbornene-2-R1a, 5-norbornene-2,2-R1a, 5-norbornene-3-R1a, 5-norbornene-3,3-R1a, 5-norbornene-2,3-R1a, or 5-norbornene-2-R1a-3-R1b, where R1a and R1b, independently, represent an alkyl or aryl group. Specific, non-limiting examples of norbornenes contemplated for use in the present invention include norbornene, 5-norbornene-2-methanol, cis-5-norbornene-endo-2,3-dicarboxylic anhydride, 5-norbornene-2,2-dimethanol, 5-norbornen-2-ol, norbornadiene, 5-norbornene-2,3-diphenyl, cis-5-norbornene-endo-2,3-dicarboxylic acid dimethyl ester, 5-norbornen-2-yl-acetate and 5-norbornene-2-carboxyaldehyde.
The Pd(II)-based catalyst system of the present invention is a dimer catalyst that may be characterized by the formula [(L)Pd(R)(X)]2. In this dimer catalyst, L is a monodentate phosphorus or nitrogen ligand. In general, suitable monodentate phosphorus ligands are those that conform to the formula R23P, where R2 is alkyl and/or aryl group. Non-limiting examples of such monodentate phosphorus ligands include triphenyl phosphine (PPh3), tricyclohexyl phosphine (PCy3), trimethyl phosphine (PMe3), triethyl phosphine (PEt3), tri-n-propyl phosphine (P(n-Pr)3), tri-n-butyl phosphine (P(n-Bu)3), tri-t-butyl phosphine (P(t-Bu)3) and tri-p-tolyl phosphine (P(p-Tol)3). Specific, non-limiting examples of mixed alkyl and aryl phosphines that are suitable for use in the invention include methyldiphenyl phosphine (P(Me)(Ph)2), phenyldimethyl phosphine (PPh(Me)2), ethyldiphenyl phosphine (P(Et)(Ph)2), and phenyldiethyl phosphine (PPh(Et)2).
Generally, monodentate nitrogen ligands which may be used in the present invention are aromatic or heterocyclic amines, such as pyridine, t-butyl pyridine, aniline, trimethyl aniline and imidazole, or compounds that conform to the formula R3N, where R3 is an alkyl group, such as methyl (CH3), ethyl (CH2CH3), propyl (CH2CH2CH3), n-butyl (CH2CH2CH2CH3), or t-butyl (Cxe2x80x94(CH3)3), or an aryl group, such as phenyl (C6H6) or p-tolyl (C7H8).
X is an anionic group, such as chlorine or bromine, or a carboxylate, such as acetate, propionate, trifluoroacetate, and benzoate; and R is an alkyl group, such as methyl (CH3), ethyl (CH2CH3), propyl (CH2CH2CH3), n-butyl (CH2CH2CH2CH3), or t-butyl (Cxe2x80x94(CH3)3), or an aryl group, such as phenyl (C6H6) or p-tolyl (C7H8).
Typically, the catalyst is formed by reaction of 1 equivalent of the monodentate ligand with [(1,5-cyclooctadiene)Pd(Me)(X)] in situ, as illustrated by the equation (using X=chlorine):
Catalyst formation may be monitored by 1H and 31P{1H} NMR. For the PCy3 analog, the movement of the methyl signal in the proton spectrum from a singlet at 1.12 ppm in the starting material to a triplet at 0.11 ppm in the dimer upon addition of 1 equivalent PCy3 indicates the formation of the desired product. Additionally, the appearance of uncoordinated 1,5-cyclooctadiene signals at 5.55 and 2.34 ppm in the proton NMR and a 25.6 ppm 31P{1H} NMR signal for [(PCy3)Pd(Me)(Cl)]2 are observed.
The relevance of the alkyl (or aryl) group in the present dimer catalyst system was explored by attempting to homopolymerize methyl acrylate using a dimer catalyst that was devoid of alkyl (or aryl) groups. It was found that methyl acrylate would not polymerize when reacted in the presence of a Pd(II) catalyst that was prepared by reacting [(1,5-cyclooctadiene)Pd(Cl)2] with 1 equivalent of tricyclohexyl phosphine (PCy3). This indicated that the alkyl (or aryl) group is essential to the polymerization mechanism.
The copolymers of the present invention may be tailored in norbornene to acrylate ratio by varying the ratio of the respective monomers in the reaction mixture and by varying the ligands utilized in the catalyst system. Typically, the ratio of norbornene monomer to acrylate monomer in the starting mixture is from about 100:1 to about 1:100. In preferred aspects of the invention, the ratio of norbornene monomer to acrylate monomer that is added to the reactor is from about 10:1 to about 1:10. By varying the ratio of the norbornene monomer to acrylate monomer in the starting mixture copolymers having a very wide range of acrylate-derived units and norbornene-derived units can be prepared. For example, copolymers containing from about 5 to about 95 mole % acrylate-derived units and from about 95 to about 5 mole % norbornene-derived units may be prepared in accordance with this invention. In certain preferred aspects, copolymers containing from about 15 to about 90 mole % acrylate-derived units and from about 85 to about 10 mole % norbornene-derived units are prepared; and in other preferred aspects, copolymers containing from about 25 to about 80 mole % acrylate-derived units and from about 75 to about 20 mole % norbornene-derived units are prepared. In still other preferred aspects, copolymers containing from about 35 to about 55 mole % acrylate-derived units and from about 45 to about 65 mole % norbornene-derived units are prepared.
The polymerization preferably is carried out in the liquid phase using a solvent, such as dichloromethane (CH2Cl2), benzene (C6H6), chlorobenzene (C6H5Cl) or hexane (C6H14). Other solvents that may be used as the polymerization medium include, for example, pentane (C5H12), toluene (C7H8), and chloroform (CHCl3).
The polymerization in accordance with this invention may be carried out at temperatures ranging from about 0 to about 200xc2x0 C. Typically, however, the polymerization will be carried out at a temperature of from about 30 to about 80xc2x0 C., e.g., about 50xc2x0 C. The pressure at which the polymerization is carried out is not critical.
The various aspects of the invention will be appreciated more fully in light of the following illustrative examples:

Palladium (II) catalyzed polymerization of norbornene and acrylates


A valve deactivation lifter including means for restricting relative rotation between the pin housing and the lifter body. When used in a V-style or slant engine, a prior art deactivation lifter can be subject to oil drainage during engine shutdown if the oil supply port in the pin housing rests in the “down” position. In an improved lifter, relative rotation between the pin housing and the lifter body is limited and the pin housing is oriented such that the oil supply port is never on the underside of the pin housing. Rotation may be limited by any of several means, for example, a ball disposed in a dimple in the pin housing and extending into a longitudinal groove in the lifter body, and a flat on the pin housing and locking means installed in the lifter body to engage the flat and thus prevent rotation of the pin housing.

It is well known that overall fuel efficiency in a multiple-cylinder internal combustion engine can be increased by selective deactivation of one or more of the engine valves under certain engine load conditions. A known approach to providing selective deactivation is to equip the hydraulic lifters for those valves with means whereby the lifters may be rendered incapable of transferring the cyclic motion of engine cams into reciprocal motion of the associated pushrods. Typically, a deactivation lifter includes, in addition to the conventional hydraulic lash elimination means, concentric inner and outer portions which are mechanically responsive to the pushrod and to the cam lobe, respectively, and which may be selectively latched and unlatched to each other, typically by the selective engagement of pressurized engine oil.
U.S. Pat. No. U.S. Pat. No. 6,164,255, issued Dec. 26, 2000 to Maas et al., discloses a deactivation hydraulic valve lifter comprising an outer section which encloses an inner section that is axially movable, the outer section having a pot-shaped configuration and a bottom which comprises an end for cam contact and separates the inner section from a cam whereby, upon coupling of the sections by a coupling means, a high lift of a gas exchange valve is effected, and upon uncoupling of the sections, a zero lift. The disclosed coupling means is a single round pin disposed in a transverse bore in the inner section and biased outwards by a coil spring to engage a mating round bore in the outer section, whereby the two sections may be locked together. The bore in the outer section is matable with an oil gallery in the engine block, whereby pressurized oil may be introduced against the head of the locking pin to urge the pin hydraulically into retraction within the inner section to uncouple the inner and outer sections and thereby deactivate the associated engine valve.
U.S. Pat. No. 6,196,175 B1, issued Mar. 6, 2001 to Church et al. discloses a mechanism similar to that disclosed by Maas et al. A single locking pin is selectively extendable from the pin housing into a round locking bore in the lifter body. In addition, an alignment member extends from the pin housing opposite the locking bore through a slot in the lifter body and engages an axially extending slot in the engine block to prevent rotation of the pin housing relative to the lifter body, thus maintaining alignment of the locking pin with the locking bore.
U.S. Pat. No. 6,513,470 B1, issued Feb. 4, 2003 to Hendriksma et al., discloses an improved mechanism useful in a valve deactivating hydraulic lifter. The mechanism includes a pair of opposed locking pins disposed in a transverse bore in the inner section to engage the outer section in two separate locations 180° apart. Further, the outer section single round bore of Maas et al. and Church et al. is replaced by an annular groove formed in the inner wall of the outer section and defining an annular locking surface such that all rotational alignment requirements are removed, the pins being engageable into the groove at all rotational positions of the inner section within the outer section. The groove communicates, similarly to the round bore in Haas et al., with an oil gallery in the engine block for actuation and deactuation of the locking pins. Since the lifter in Hendriksma, et al. uses two locking pins instead of one, as disclosed in Maas, et al. and Church et al, the force applied through the lifter to open the valve is centralized advantageously along the centerline of the lifter thereby improving the smoothness of operation of the locking feature. Further, the pins are flattened in the portion which engages the locking surface to distribute the load over a broad area of the locking surface.
Hendriksma et al. discloses that complete rotational freedom of the pin housing within the lifter body is an advantage in that wear is distributed over time along the entire length of the annular locking surface. However, such total freedom can also be disadvantageous. When the lifter is used in an application such as a V-style or slant engine where the lifter body can be tipped as much as 45° from vertical, the rotational orientation of the pin housing within the lifter body at the time of engine shutdown can be very important. If the oil supply port through the pin housing and the oil supply port in the plunger element are both on the underside of the pin housing when it comes to rest, oil within the plunger element can leak therefrom via tolerances between the pin housing and the lifter body. Then, when the engine is restarted, air is drawn into the high pressure chamber of the lash adjuster causing noisy engine operation for a period of time after the engine is restarted, before the plunger element can be refilled by engine oil. Such noisy operation is obviously highly undesirable and can lead to premature wear of engine components.
It is a principal object of the present invention to provide a deactivation lifter having means for preventing draining of oil from the lifter during periods of engine shutdown.


In order to drive a liquid crystal at a speed equivalent to or higher than CRT displays, in a liquid crystal display device made of a liquid crystal and two electrodes sandwiching the liquid crystal to display images by applying a voltage based on gradation data between the two electrodes, a predetermined voltage independent from the gradation data is applied across the two electrodes for a predetermined length of time in predetermined intervals.

1. Field of the Invention
This invention relates to a high-speed driving method of a liquid crystal for driving a liquid crystal, particularly for gradation display, at a high speed.
2. Related Art
As already known, when two transparent flat plates having transparent electrodes and sandwiching a liquid crystal are placed between two polar zigplates, transmittance of light passing through the polarizing plates changes with the voltage applied across the transparent electrodes.
Since liquid crystal display devices based on the above principle can be shaped flat and are operative with low electric power, they have been widely used in wrist watches, electronic calculating machines, and so forth.
In recent years, they are also used in combination with color filters to make up color display devices in note-type personal computers and small liquid crystal TV sets, for example.
In liquid crystal display devices combined with color filters to display color images, three dots of different colors, namely, red, green and blue, are combined to display desired colors.
A problem with the use of color filters lies in that color filters are very expensive and need a high accuracy when bonded to panels. Moreover, they need a triple number of dots to ensure an equivalent resolution as compared with black-and-white liquid crystal display panels. Therefore, typical liquid crystal color panels require a triple number of drive circuits in the horizontal direction. This means an increase of the cost of drive circuits themselves and the cost for an increased man-hour for connecting drive circuits to the panel at a triple number of points.
Another problem with the use of color filters is their optical transmittance as low as 20% approximately. When color filters are used, the brightness decreases to approximately one fifth, and a large amount of electric power is consumed for back-lighting to compensate the brightness.
There is another problem in conventional liquid crystal devices, namely, slow responses of liquid crystals. In this respect, liquid crystal display devices have been inferior to CRT displays especially when used as TV displays for displaying moving images or as personal computer displays required to quickly follow the movements of a mouse cursor.
Japanese Patent Laid-Open Publication No. hei 1-179914 discloses a color liquid crystal display device to display color images by combining a black-and-white panel and tricolor back-lighting instead of using color filters. This method may enable realization of high-fidelity color images inexpensively, as compared with the method using color filters. In order to realize images without flickers, this method needs an ON-OFF frequency of each color backlight as high as 40 Hz or more, and more preferably 60 Hz or more. As a result, the frequency of liquid crystal display becomes thrice that frequency, namely, 180 Hz, and the cycle of liquid crystal display becomes 5.5 ms. Regarding the ON time of backlight, it must be at least 2 ms, which is two fifths the display cycle, to ensure that a display luminance equivalent to that obtained by using one white fluorescent lamp be obtained by three color tubes, one for each of red, green and blue colors, considering that, when cold cathode ray tubes, such as those using red, green and blue short-afterglow fluorescent materials, optical conversion efficiency relative to input power decreases nearly to a half, but the transmittance increases to five times due to removal of color filters. Therefore, if the duration of 2 ms of the display period 5.5 ms is used for turning on the backlight, then the response speed of the liquid crystal panel is high enough to stabilize liquid crystal display within 3.5 ms. When a graphic image on a display is scanned, for example, even at a high scanning speed as high as 1000 Hz to prevent color striation or defective coloring on the screen, additional 1 ms is further required, and the response speed of the liquid crystal panel must be higher enough to stabilize liquid crystal display within 2.5 ms.
However, in case of liquid crystal display devices using typical nematic TN liquid crystal such as TN liquid crystal or STN liquid crystal, for example, their response speeds are as slow as decades of ms to hundreds of ms.
There are some other proposals to use ferroelectric liquid crystals or anti-ferroelectric liquid crystals to provide liquid crystal panels operative at a high speed. However, no such device has been brought into practice mainly because cell gaps of the liquid crystal must as small as 1 xcexcm or less and are therefore difficult to make. It is known, as means for increasing the response speed of a liquid crystal panel, that the response speed is increased in inverse proportion to the square of the cell gap when the cell gap is narrowed. In case of TN liquid crystals, the response speed can be readily increased to 2 through 3 ms or less by selecting a low-viscosity liquid crystal material and narrowing the cell gap to 2 xcexcm. Even when the cell gap is as narrow as 2 xcexcm, there is an allowance of xc2x10.4 xcexcm for acceptably uniform display, and large-scale panels can be manufactured without serious problems. Therefore, eight-color display with two tones for each color can be realized by using three-color back-lighting and using a narrow-gap TN liquid crystal.
Liquid crystal display devices are more and more widely used as display devices for personal computers in lieu of CRT displays to save the space and electric power. More and more applications for personal computers are designed for multi-color display, and display devices are required to display 16,777,216 colors with 256 tones for each color. Also for use other than personal computers, video images require multi-color display of 64 tones for each color.
There are some schemes for gradation display of liquid crystal panels, such as a method using a voltage to control color gradation or tones in case of liquid crystals like TN liquid crystals or anti-ferroelectric liquid crystals exhibiting relatively moderate changes in transmittance with voltage, a method for display by changing the ratio between the time for display white and the time for displaying black or a method for collecting and averaging a plurality of pixels, in case of liquid crystals such as STN liquid crystals or ferroelectric liquid crystals having only two values of transmittance relative to voltage. However, in the color display method using three-color back-lighting, since the display cycle is relatively short, the method by changing the ratio of white and black display periods of time cannot provide a desired number of tones because the operation frequency of the control circuit increases too high. The method by collecting and averaging a plurality of dots removes the merit of reducing the number of pixels to one third as compared to the color-filter method.
Therefore, in order to realize multi-color display by the color display method using three-color back-lighting, control of tones by voltage control must be used. However, response speeds of liquid crystal panels, in general, are such that changes to or from an intermediate tone are slower by several times or more than changes from white to black or from black to white.
It is therefore an object of the invention to provide a high-speed driving method of a liquid crystal, which increases the response speed sufficiently to enable color display by three-color back-lighting or promise a performance equivalent to or higher than that of CRT displays in reproduction of moving images.
According to the invention, there is provided a high-speed driving method of a liquid crystal for a liquid crystal display device made up of a liquid crystal and two electrodes sandwiching the liquid crystal to display images by applying a voltage based on gradation data between the two electrodes, characterized in applying a predetermined voltage independent from said gradation data across said two electrodes for a predetermined length of time in predetermined intervals.
Especially in color display using three-color back-lighting, it is remarked that the duration of time where all of three color backlight lamps are OFF comes about periodically. By using the fact that, in the duration of time where all of the three color backlight lamps are OFF, the quality of images is not affected by any state of transmittance of the liquid crystal panel, and by applying a voltage to the liquid crystal at a g different from that of a driving circuit of a conventional liquid crystal panel, the response speed of the liquid crystal panel can be increased for all sorts of images including intermediate tone images to realize a bright and low-consumption color liquid crystal panel.

High-speed driving method of a liquid crystal