A photoconductor comprises a substrate and a charge generation layer comprising cyclic carbonate polymer and a charge generation molecule. The photoconductor exhibits improved electrical characteristics.

The present invention is directed toward photoconductors and compositions used to form photoconductors. More particularly, the invention is directed towards photoconductors comprising a substrate and a charge generation layer, wherein the charge generation layer comprises a cyclic carbonate polymer. The invention is further directed toward methods of improving electrical characteristics of photoconductors, and methods of improving the stability of photoconductors, as well as binder blends comprising a cyclic carbonate polymer.
In electrophotography, a latent image is created on the surface of an imaging member such as a photoconducting material by first uniformly charging the surface and then selectively exposing areas of the surface to light. A difference in electrostatic charge density is created between those areas on the surface which are exposed to light and those areas on the surface which are not exposed to light. The latent electrostatic image is developed into a visible image by electrostatic toners. The toners are selectively attracted to either the exposed or unexposed portions of the photoconductor surface, depending on the relative electrostatic charges on the photoconductor surface, the development electrode and the toner.
Typically, a dual layer electrophotographic photoconductor comprises a substrate such as a metal ground plane member on which a charge generation layer (CGL) and a charge transport layer (CTL) are coated. The charge transport layer contains a charge transport material which comprises a hole transport material or an electron transport material. For simplicity, the following discussions herein are directed to use of a charge transport layer which comprises a hole transport material as the charge transport compound. One skilled in the art will appreciate that if the charge transport layer contains an electron transport material rather than a hole transport material, the charge placed on a photoconductor surface will be opposite that described herein.
When the charge transport layer containing a hole transport material is formed on the charge generation layer, a negative charge is typically placed on the photoconductor surface. Conversely, when the charge generation layer is formed on the charge transport layer, a positive charge is typically placed on the photoconductor surface. Conventionally, the charge generation layer comprises the charge generation compound or molecule, for example a squaraine pigment, a phthalocyanine, or an azo compound, alone or in combination with a binder. The charge transport layer typically comprises a polymeric binder containing the charge transport compound or molecule. The charge generation compounds within the charge generation layer are sensitive to image-forming radiation and photogenerate electron-hole pairs therein as a result of absorbing such radiation. The charge transport layer is usually non-absorbent of the image-forming radiation and the charge transport compounds serve to transport holes to the surface of a negatively charged photoconductor. Photoconductors of this type are disclosed in the Adley et al, U.S. Pat. No. 5,130,215 and the Balthis et al, U.S. Pat. No. 5,545,499.
Various polymers are known for use in charge generation and/or charge transport layers. For example, polycarbonate resins, including aromatic polycarbonate resins, are taught in U.S. Pat. Nos. 5,378,567, 5,942,363, and 6,066,428, for use in photoconductors. Miyamoto et al., U.S. Pat. No. 5,521,041, teach an electrophotographic photoreceptor comprising an electroconductive substrate and a photosensitive layer wherein the photosensitive layer comprises a polycarbonate. Miyamoto et al. teach the polycarbonate may be prepared by allowing a dihydric phenol to react with a carbonate precursor, such as phosgene, in the presence of an end terminator.
While the charge transport layers and charge generation layers of photoconductors generally comprise binders, the electrical sensitivity of a charge generation layer can be detrimentally affected by the polymer binders. For example, the use of polyvinylbutyral as a charge generation layer binder is advantageous in that it significantly improves adhesion of the charge generation layer to the substrate. Unfortunately, polyvinylbutyral can disadvantageously affect electrical characteristics of the resulting photoconductor in causing, inter alia, high dark decay and residual voltage properties. Polycarbonates have been known to improve the mechanical properties of a photoconductor, particularly impact resistance.
Thus, there is a need for binder and binder blends for use in charge generation layers which provide the photoconductors with good mechanical properties without significantly decreasing electrical sensitivity of photoreceptors.
Accordingly, it is an object of this invention to obviate various problems of the prior art. It is another object of this invention to provide photoconductors having good electrical characteristics, particularly good electrical sensitivity.
It is a further object of this invention to provide photoconductors which have reduced dark decay and/or improved print stability and fatigue characteristics, and/or which charge and discharge in a very short time. It is yet another object of this invention to provide binder blends which do not compromise the adhesion of coatings onto substrates.
In one embodiment, the invention is directed to photoconductors comprising a substrate and a charge generation layer comprising a cyclic carbonate polymer.
In accordance with another embodiment, the invention, is directed to methods of improving an electrical characteristic of a photoconductor. The methods comprise forming a photoconductor comprising a substrate and a charge generation layer comprising a charge generation molecular and a cyclic carbonate polymer.
In accordance with a further embodiment aspect of the invention there are provided methods of improving the stability of a photoconductor comprising a charge generation layer comprising a charge generation molecule and polyvinylbutyral, the method comprising the step of adding to the charge generation layer a cyclic carbonate polymer. In accordance with yet another embodiment of the invention there are provided charge generation layer-forming compositions comprising pigment, solvent and a binder blend, wherein the binder blend comprises polyvinylbutyral and a cyclic carbonate polymer.
In accordance with one embodiment of the invention, there are provided binder blends comprising a first binder selected from the group consist of cyclic carbonate polymers and mixtures thereof, and a second binder which is other than a cyclic carbonate polymer.
Photoconductors comprising charge generation layers in accordance with the present invention have good electrical characteristics, particularly good electrical sensitivity, low dark decay and/or stable fatigue through life. Further, in various embodiments, the photoconductors charge and discharge at a very short time interval, and thus are useful for high speed printing in the range of from about 30 to about 50 pages per minute.
These and additional objects and advantages will become more fully apparent in view of the following description.
The charge generation layers according to the present invention are suitable for use in dual layer photoconductors. Such photoconductors generally comprise a substrate, a charge generation layer (CGL) and a charge transport layer (CTL). The photoconductors may also comprise a sub-layer to assist in the adhesion of the charge generation and charge transport layers, or a protective coating to reinforce the durability of the charge generation and charge transport layers. Some substrates, such as aluminum, may be anodized. In one embodiment the substrate is anodized aluminum or aluminized MYLAR(copyright). While various embodiments of the invention discussed herein refer to the charge generation layer as being formed on the substrate, with the charge transport layer formed on the charge generation layer, it is equally within the scope of the present invention for the charge transport layer to be formed on the substrate with the charge generation layer formed on the charge transport layer.
The present invention is directed toward photoconductors comprising a charge generation layer wherein the charge generation layer comprises a cyclic carbonate, as well as to charge generation compositions used to form such photoconductors. Photoconductors comprising a charge generation layer (CGL) in accordance with the present invention exhibit improved electrical characteristics such as improved photosensitivity, reduced dark decay, and/or reduced fatigue.
As used herein, xe2x80x9ccharge voltagexe2x80x9d refers to the voltage applied on a drum by a charge roll or corona. xe2x80x9cDischarge voltagexe2x80x9d refers to the voltage on the drum after shining light on the drum. Discharge voltage may be measured at several different light energies. Whereas the streak voltage corresponds to the voltage measured at lower laser light energy (about 0.2 microjoules/cm2), the discharge voltage (also referred to as residual voltage) corresponds to voltage at higher laser energy.
Photoconductor drums may exhibit a loss of charge in the dark, i.e., may lose some charge before a light source discharges the charge. As used herein, xe2x80x9cdark decayxe2x80x9d refers to the loss of charge from the surface of a photoconductor when it is maintained in the dark. Dark decay is an undesirable feature as it reduces the contrast potential between image and background areas, leading to washed out images and loss of gray scale. Dark decay also reduces the field that the photoconductive process will experience when light is brought back to the surface, thereby reducing the operational efficiency of the photoconductor.
As used herein, xe2x80x9cfatiguexe2x80x9d refers to the tendency for a photoconductor to exhibit increases (negative) or decreases (positive) in its discharge voltage. Fatigue is undesirable as it reduces the development factor resulting in light or washed out print or dark print, as well as print that varies from page to page.
As used herein, xe2x80x9csensitivityxe2x80x9d or xe2x80x9cphotosensitivityxe2x80x9d refers to the ability of a photoconductor to discharge its voltage efficiently. The photosensitivity may be measured as the amount of light energy, in microjoules/cm2, required to reduce the photoconductor""s voltage from its initial charge to a lower charge. The photoconductors may be subjected to sensitivity measurements using a sensitometer fitted with electrostatic probes to measure the voltage magnitude as a function of light energy shining on the photoconductor surface. It is undesirable for a photoconductor to have poor sensitivity for such a photoconductor would require a large amount of light energy to discharge its voltage.
Additionally, the present invention is directed toward compositions used to form CGLs, referred to as charge generation layer-forming compositions. Photoconductors of the present invention comprise a substrate and a charge generation layer formed from a charge generation layer-forming composition. The charge generation composition comprises a cyclic carbonate polymer, preferably the charge composition comprises a binder blend of a cyclic carbonate polymer and a binder other than a cyclic carbonate. Suitable binders conventionally employed in the art, include, but are not limited to, vinyl polymers such as polyvinylchloride, polyvinylbutyral and polyvinylacetate; polycarbonate polymers and copolymers other than cyclic carbonates, including polyester carbonates; acrylic resins; polyamides; polyacrylamides; polyurethanes; butyral resins, epoxy resins and phenolic resins. Preferably the binder blend comprises a cyclic carbonate polymer and a polyvinylbutyral.
Cyclic Carbonate Polymers
As used herein, cyclic carbonate polymers are polymers comprising a carbonate in the form of a cyclic moiety. As used herein, cyclic carbonate polymers do not refer to polycarbonates which comprise a phenol ring or a cycloalkyl compound wherein the phenol ring or cycloalkyl compound do not comprise a section of the cyclic carbonate moiety. For example, poly (p-octylphenol-formaldehyde) and polycarbonate-A comprise phenol groups, however, these groups are not part of a cyclic carbonate moiety, and these compounds are not considered to be cyclic carbonate polymers as defined and used herein.
Cyclic carbonates have the general structure:
wherein X comprises at least one carbon atom, preferably from about 3 to about 5 carbon atoms. In one embodiment, X has the structure:
wherein R and R2 are CH or a substituted or unsubstituted aryl ring, and R1 is (CH2)n wherein n is at least about 1, preferably from about 1 to about 3, and wherein Z indicates a bond to a carbon in a polymer chain.
Suitable cyclic carbonate polymers may comprise the moieties:
or mixtures thereof, wherein each R4 is independently selected from the group consisting of hydrogen, aryl groups, and alkyl groups, preferably alkyl groups having from about 4 to about 8 carbon atoms.
Cyclic carbonate polymers may be prepared by reacting hydroxy-containing polymers with carbonyl-donating compounds. Generally the weight ratio of hydroxy-containing polymer to carbonyl-donating compound is from about 6:1 to about 1:1, preferably from about 1:1 to about 3:1. Carbonyl-donating compounds include phosgene compounds such as phosgene, triphosgene, diphosgene, bromophosgene, bis (2,4,6-trichlorophenol) carbonate, bis (2,4-dichlorophenol) carbonate and bis (2-cyanophenol) carbonate. A preferred carbonyl-donating compound is triphosgene (bis (trichloromethyl) carbonate). Preferred cyclic carbonates include carbonates derived from polyvinylbutyral polymers or copolymers, such as poly(vinylbutyral-vinylalcohol-vinylacetate) resin, and phenol-formaldehyde resins, such as 4-t-butylphenol-formaldehyde, 4-phenylphenol-formaldehyde, poly(p-octylphenol-formaldehyde), poly(bisphenol-A-co-formaldehyde), and poly(bisphenol-A-co-formaldehyde-co-butylphenol).
The synthesis of cyclic carbonate polymers may be carried out in a manner similar to that reported by H. Mandal and A. S. Hay, Polym. Prepr. Am. Chem. Soc., Div. Polym. Chem. 38(2), 1993-1994 (1997), and H. Mandal and A. S. Hay, High Perform. Polym., 9, 215-227 (1997) incorporated herein by reference. For example, a hydroxy-containing polymer, such as a polyvinylbutyral resin or a phenol-formaldehyde resin, may be reacted with a carbonyl-donating compound, such as triphosgene, in the presence of a solvent, such as tetrahydrofuran, and, optionally, an acid scavenger, such as pyridine.
While not being bound by theory, it is believed that the reaction of a poly (vinylbutyral-vinyl acetate-vinyl alcohol) (PVB), may form both a soluble polymer and an insoluble polymer. It is believed that in some embodiments the PVB resin may have a hydroxyl content of about 30%, and that both intra and interchain condensation with the triphosgene may occur resulting in either an insoluble (cross-linked) or soluble (intra-chained) polymer. A mixture of both the soluble and insoluble polymer may be used in the formation of the charge generation compound and resulting charge generation layer. While not being bound by theory, the reaction of the polyvinylbutyral and triphosgene is believed to proceed as set forth below in Reaction Sequence 1.
The cyclic carbonate polymers may also be prepared using resins comprising phenolic groups, such as phenolic novolac resins. Phenolic novolac resins are known in the art, and typically comprise a repeating unit of a formula:
wherein R comprises a C1-8 alkyl group and a is from 0 to 3. Phenolic novolac resins typically have a number average molecular weight of at least about 600. Suitable phenolic novolac resins include poly(p-octylphenol-formaldehyde), poly(bisphenol-A-co-formaldehyde), and poly(bispehnol-A-co-formaldehyde-co-butylphenol).
The cyclic carbonates may be prepared by condensing a phenolic novolac with a carbonyl-donating compound, such as triphosgene, in the presence of a solvent, such as tetrahydrofuran, and, optionally, an acid scavenger such as pyridine.
While not being bound by theory, the reaction between the carbonyl-donating compound and several different phenolic novolac resins is believed to proceed as set forth in Reaction Sequence 2.
Preferred cyclic carbonate polymers are soluble in organic solvents. Particularly preferred cyclic carbonate polymers include those which are soluble in tetrahydrofuran (THF), chlorinated hydrocarbons such as dichloromethane and chloroform, dioxane and polar aprotic solvents such as dimethyl acetamide, dimethyl formamide, N-methyl-2-pyrrolidinone and methyl sulfoxide.
Charge Generation Compositions and Layers
Charge generation layers in accordance with the present invention comprise a charge generation molecule and a cyclic carbonate polymer, and may further comprise a binder other than the cyclic carbonate polymer, such as polyvinylbutyral, polyvinylchloride, polyvinylacetate, polycarbonate polymers and copolymers other than cyclic carbonates; acrylic resins; polyamides; polyacrylamides, polyurethanes; epoxy resins; and phenolic resins.
The charge generation layers are formed from a charge generation layer-forming composition comprising the charge generation molecule and the cyclic carbonate polymer. Preferably, the charge generation layer-forming composition comprises a binder blend of a cyclic carbonate polymer and a second binder. In one embodiment, the second binder comprises a polyvinylbutyral polymer.
The binder blend may comprise the cyclic carbonate polymer and the second binder in a weight ratio of from about 95:5 to about 5:95, preferably from about 75:25 to about 25:75, more preferably about 50:50. The charge generation layer generally comprises, by weight, from about 12% to about 45%, preferably from about 26% to about 33%, of the cyclic carbonate polymer, from about 12% to about 45%, preferably from about 26% to about 33%, of the second binder, and from about 30% to about 60%, preferably from about 35% to about 45%, of the charge generation molecule.
Polyvinylbutyral polymers are well known in the art and are commercially available from various sources. These polymers are typically made by condensing poly(vinyl alcohol-co-vinyl acetate) with butyraldehyde in the presence of an acid catalyst, for example sulfuric acid, and contain a repeating unit of formula:
Typically, the polyvinylbutyral polymer will have a number average molecular weight of from about 20,000 to about 300,000.
Various organic and inorganic charge generation compounds are known in the art, any of which are suitable for use in the charge generation layers of the present invention. One type of charge generation compound which is particularly suitable for use in the charge generation layers of the present invention comprises squarylium-based pigments, including squaraines. Squarylium pigment may be prepared by an acid route such as that described in U.S. Pat. Nos. 3,617,270, 3,824,099, 4,175,956, 4,486,520 and 4,508,803, which employs simple procedures and apparatus, has a short reaction time and is high in yield.
Specific squarylium pigments suitable for use in the present invention may be represented by the structural formula:
wherein R1 represents hydroxy, hydrogen or C1-5 alkyl, preferably hydroxy, hydrogen or methyl, and each R2 individually represents C1-5 alkyl or hydrogen. In a further preferred embodiment, the pigment comprises a hydroxy squaraine pigment wherein each R1 in the formula set forth above comprises hydroxy.
Another type of pigment which is particularly suitable for use in the charge generation layers of the present invention comprises the phthalocyanine-based compounds. Suitable phthalocyanine compounds include both metal-free forms such as the X-form metal-free phthalocyanines and the metal-containing phthalocyanines. In a specific embodiment, the phthalocyanine charge generation compound may comprise a metal-containing phthalocyanine wherein the metal is a transition metal or a group IIIA metal. Of these metal-containing phthalocyanine charge generation compounds, those containing a transition metal such as copper, titanium or manganese or containing aluminum or gallium as a group IIIA metal are preferred. These metal-containing phthalocyanine charge generation compounds may further include oxy, thiol or dihalo substitution. Titanium-containing phthalocyanines as disclosed in U.S. Pat. Nos. 4,664,997, 4,725,519 and 4,777,251, including oxo-titanyl phthalocyanines, and various polymorphs thereof, for example type IV polymorphs, and derivatives thereof, for example halogen-substituted derivatives such as chlorotitanyl phthalocyanines, are suitable for use in the charge generation layers of the present invention.
Additional conventional charge generation compounds known in the art, including, but not limited to, diazo compounds, for example as disclosed in the Ishikawa et al., U.S. Pat. No. 4,413,045, and tris and tetrakis compounds as known in the art, are also suitable for use in the charge generation layers of the present invention. It is also within the scope of this invention to employ a mixture of charge generation pigments or compounds in the charge generation layer.
In one embodiment of the invention, the charge generation molecule is a pigment selected from the group consisting of azo pigments, anthraquinone pigments, polycyclic quinone pigments, indigo pigments, diphenylmethane pigments, azine pigments, cyanine pigments, quinoline pigments, benzoquinone pigments, napthoquinone pigments, naphthalkoxide pigments, perylene pigments, fluorenone pigments, squarylium pigments, azuleinum pigments, quinacridone pigments, phthalocyanine pigments, naphthaloxyanine pigments, porphyrin pigments and mixtures thereof. In a preferred embodiment, the charge generation molecule is a pigment selected from the group consisting of hydroxy squaraines, Type IV oxotitanium phthalocyanines, and mixtures thereof.
The charge generation layers may comprise the charge generation compound in amounts conventionally used in the art. Typically, the charge generation layer may comprise from about 5 to about 80, preferably at least about 10, and more preferably from about 15 to about 60, weight percent of the charge generation compound, and may comprise from about 20 to about 95, preferably not more than about 90, and more preferably comprises from about 40 to about 85, weight percent of total binder, all weight percentages being based on the charge generation layer. The charge generation layers may further contain any conventional additives known in the art for use in charge generation layers. The binder may be a blend comprising cyclic carbonate polymer and one or more second binders other than a cyclic carbonate polymer.
To form the charge generation layers according to the present invention, the binder and the charge generation compound are dissolved and dispersed, respectively, in an organic liquid. Although the organic liquid may generally be referred to as a solvent, and typically dissolves the cyclic carbonate polymer and any additional binder, the liquid technically forms a dispersion of the pigment rather than a solution. The cyclic carbonate polymer, pigment and additional binder may be added to the organic liquid simultaneously or consecutively, in any order of addition. Suitable organic liquids are preferably essentially free of amines and therefore avoid environmental hazards conventionally incurred with the use of amine solvents. Suitable organic liquids include, but are not limited to, tetrahydrofuran, cyclopentanone, 2-butanone and the like. Additional solvents suitable for dispersing the charge generation compound, cyclic carbonate polymer and any additional binder will be apparent to those skilled in the art.
In one embodiment the charge generation layer-forming composition generally comprises, by weight, from about 1% to about 25% by weight of solids. More preferably, the charge generation layer-forming composition comprises from about 1% to about 5%, by weight, of solids. In one specific embodiment, the charge generation layer-forming composition comprises from about 3% to about 4%, by weight, of solids. In a more specific embodiment, the charge generation layer-forming composition comprises from about 0.1% to about 20%, preferably from about 0.5% to about 2%, of the polyvinylbutyral and from about 0.1% to about 20%, preferably from about 0.5% to about 2% of the cyclic carbonate polymer. The polyvinylbutyral and the cyclic carbonate polymer form a binder blend. The weight ratio of polyvinylbutyral and the cyclic carbonate polymer in the binder blend is from about 95:5 to about 5:95, preferably from about 75:25 to about 25:75, more preferably about 50:50.
In accordance with techniques generally known in the art, the charge generation layer-forming composition preferably contains not greater than about 10 weight percent solids comprising the cyclic carbonate polymer, any additional binder and charge generation compound in combination. The compositions may therefore be used to form a charge generation layer of desired thickness, typically not greater than about 5 microns, and more preferably not greater than about 1 micron, in thickness. Additionally, a homogeneous layer may be easily formed using conventional techniques, for example dip-coating or the like. These compositions also reduce any wash or leach of the charge generation compound into a charge transport layer coating which is subsequently applied to the charge generation layer.
The charge generation layers according to the present invention exhibit good adhesion to underlying layers. Typically, the charge generation layer will be applied to a photoconductor substrate, with a charge transport layer formed on the charge generation layer. In accordance with techniques known in the art, one or more barrier layers may be provided between the substrate and the charge generation layer. Typically, such barrier layers have a thickness of from about 0.05 to about 20 microns. It is equally within the scope of the present invention that the charge transport layer is first formed on the photoconductor substrate, followed by formation of the charge generation layer on the charge transport layer.
Charge Transport Compositions and Layers
Charge transport layers in accordance with the present invention comprise at least one charge transport molecule. Conventional charge transport compounds suitable for use in the charge transport layer of the photoconductors of the present invention should be capable of supporting the injection of photo-generated holes or electrons from the charge generation layer and allowing the transport of these holes or electrons through the charge transport layer to selectively discharge the surface charge. Suitable charge transport compounds for use in the charge transport layer include, but are not limited to, the following:
1. Diamine transport molecules of the types described in U.S. Pat. Nos. 4,306,008, 4,304,829, 4,233,384, 4,115,116, 4,299,897, 4,265,990 and/or 4,081,274. Typical diamine transport molecules include benzidine compounds, including substituted benzidine compounds such as the N,N-diphenyl-N,N-bis(alkylphenyl)-(1,1xe2x80x2-biphenyl)-4,4xe2x80x2-diamines wherein the alkyl is, for example, methyl, ethyl, propyl, n-butyl, or the like, or halogen substituted derivatives thereof, and the like.
2. Pyrazoline transport molecules as disclosed in U.S. Pat. Nos. 4,315,982, 4,278,746 and 3,837,851. Typical pyrazoline transport molecules include 1-[lepidyl-(2)]-3-(p-diethylaminophenyl)-5-(p-diethylaminophenyl)pyrazoline, 1-[quinolyl-(2)]-3-(p-diethylaminophenyl)-5-(p-diethylaminophenyl)pyrazoline, 1-[pyridyl-(2)]-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-[6-methoxypyridyl-(2)]-3-(p-diethylaminostyryl)-5-(p-diethylaminophenyl)pyrazoline, 1-phenyl-3-[p-diethylaminostyryl]-5-(p-diethylaminostyryl)pyrazoline, 1-phenyl-3-[p-diethylaminostyryl]-5-(p-diethylaminostyryl)pyrazoline, and the like.
3. Substituted fluorene charge transport molecules as described in U.S. Pat. No. 4,245,021. Typical fluorene charge transport molecules include 9-(4xe2x80x2-dimethylaminobenzylidene)fluorene, 9-(4xe2x80x2-methoxybenzylidene)fluorene, 9-(2,4xe2x80x2-dimethoxybenzylidene)fluorene, 2-nitro-9-benzylidene-fluorene, 2-nitro-9-(4xe2x80x2-diethylaminobenzylidene)fluorene and the like.
4. Oxadiazole transport molecules such as 2,5-bis(4-diethylaminophenyl)-1,3,4-oxadiazole, imidazole, triazole, and others as described in German Patents Nos. 1,058,836, 1,060,260 and 1,120,875 and U.S. Pat. No. 3,895,944.
5. Hydrazone transport molecules including p-diethylaminobenzaldehyde-(diphenylhydrazone), p-diphenylaminobenzaldehyde (diphenylhydrazone), o-ethoxy-p-diethylaminobenzaldehyde (diphenylhydrazone), o-methyl-p-diethylaminobenzaldehyde (diphenylhydrazone), o-methyl-p-diethylaminobenzaldehyde (diphenylhydrazone), p-dipropylaminobenzaldehyde-(diphenylhydrazone), p-diethylaminobenzaldehyde (benzylphenylhydrazone), p-dibutylaminobenzaldehyde-(diphenylhydrazone), p-diethylaminobenzaldehyde-(diphenylhydrazone) and the like described, for example, in U.S. Pat. No. 4,150,987. Other hydrazone transport molecules include compounds such as 1-naphthalenecarbaldehyde 1-methyl-1-phenylhydrazone, 1-naphthalenecarbaldehyde 1,1-phenylhydrazone, 4-methoxynaphthlene-1-carbaldehyde 1-methyl-1-phenylhydrazone and other hydrazone transport molecules described, for example, in U.S. Pat. Nos. 4,385,106, 4,338,388, 4,387,147, 4,399,208 and 4,399,207. Yet other hydrazone charge transport molecules include carbazole phenyl hydrazones such as 9-methylcarbazole-3-carbaldehyde- 1,1-diphenylhydrazone, 9-ethylcarbazole-3-carbaldehyde-1-methyl-1-phenylhydrazone, 9-ethylcarbazole-3-carbaldehyde-1-ethyl-1-phenylhydrazone, 9-ethylcarbazole-3-carbaldehyde-1-ethyl-1-benzyl-1-phenylhydrazone, 9-ethylcarbazole-3-carbaldehyde-1,1-diphenylhydrazone, and other suitable carbazole phenyl hydrazone transport molecules described, for example, in U.S. Pat. No. 4,256,821. Similar hydrazone transport molecules are described, for example, in U.S. Pat. No. 4,297,426.
Preferably, the charge transport compound included in the charge transport layer comprises a hydrazone, an aromatic amine (including aromatic diamines such as benzidine), a substituted aromatic amine (including substituted aromatic diamines such as substituted benzidines), or a mixture thereof. Preferred hydrazone transport molecules include derivatives of aminobenzaldehydes, cinnamic esters or hydroxylated benzaldehydes. Exemplary aminobenzaldehyde-derived hydrazones include those set forth in the Anderson et al U.S. Pat. Nos. 4,150,987 and 4,362,798, while exemplary cinnamic ester-derived hydrazones and hydroxylated benzaldehyde-derived hydrazones are set forth in the copending Levin et al U.S. applications Ser. Nos. 08/988,600 and 08/988,791, respectively, all of which patents and applications are incorporated herein by reference.
In one embodiment, the charge transport compound comprises a compound selected from the group consisting of poly(N-vinylcarbazole)s, poly(vinylanthracene)s, poly(9,10-anthracenenylene-dodecanedicarboxylate)s, polysilanes, polygermanes, poly(p-phenylene-sulfide), hydrazone compounds, pyrazoline compounds, enamine compounds, styryl compounds, arylmethane compounds, arylamine compounds, butadiene compounds, azine compounds, and mixtures thereof. In a preferred embodiment, the charge transport compound comprises a compound selected from the group consisting of p-diethylaminobenzaldehyde-(diphenylhydrazone) (DEH), N,N-bis-(3-methylphenyl)-N,N-bis-phenyl-benzidine (TPD) and mixtures thereof. TPD has the formula:
The charge transport layer typically comprises the charge transport compound in an amount of from about 5 to about 60 weight percent, more preferably in an amount of from about 15 to about 40 weight percent, based on the weight of the charge transport layer, with the remainder of the charge transport layer comprising binders and any conventional additives. Any binders conventionally used in charge transport layers may be employed and include, but are not limited to, polycarbonate resins, polyester resins, polymethacrylic resins, polystyrene resins and mixtures thereof.
Suitable polycarbonates include polycarbonate-A""s, polycarbonate-Z""s, and mixtures thereof. Preferred polycarbonates have a number average molecular weight of from about 10,000 to about 100,000, more specifically from about 20,000 to about 80,000. A preferred polycarbonate includes a polycarbonate-A having the structure set forth below.
Such a polycarbonate-A is available from Bayer Corporation as MAKROLON(copyright)-5208 polycarbonate, having a number average molecular weight of about 34,000.
The charge transport layer will typically have a thickness of from about 10 to about 40 microns and may be formed in accordance with conventional techniques known in the art. Conveniently, the charge transport layer may be formed by preparing a charge transport composition, coating the charge transport composition on the respective underlying layer and drying the coating. To form the charge transport composition according to the present invention, the binder, preferably a polycarbonate, and the charge transport compound are dispersed or dissolved in an organic liquid. Although the composition which forms the charge transport layer may be referred to as a solution, the binder and charge transport compound may disperse rather than dissolve in the organic liquid, thus the composition may be in the form of a dispersion rather than a solution. The binder and charge transport compound may be added to the organic liquid simultaneously or consecutively, in any order of addition. Suitable organic liquids are preferably essentially free of amines and therefore avoid environmental hazards conventionally incurred with the use of amine solvents. Suitable organic liquids include, but are limited to, tetrahydrofuran, 1,2-dioxane, 1,4-dioxane, and the like. Additional solvents suitable for dispersing the charge transport compound and binder will be apparent to those skilled in the art.
Photoconductors
The photoconductor substrate may be flexible, for example in the form of a flexible web or a belt, or inflexible, for example in the form of a drum. Typically, the photoconductor substrate is uniformly coated with a thin layer of a metal, preferably aluminum, which functions as an electrical ground plane. In a further preferred embodiment, the aluminum is anodized to convert the aluminum surface into a thicker aluminum oxide surface. Alternatively, the ground plane member may comprise a metallic plate formed, for example, from aluminum or nickel, a metallic drum or foil, or a plastic film on which aluminum, tin oxide, indium oxide or the like is vacuum evaporated. Typically, the photoconductor substrate will have a thickness adequate to provide the required mechanical stability. For example, flexible web substrates generally have a thickness of from about 0.01 to about 0.1 microns, while drum substrates generally have a thickness of from about 0.75 mm to about 1 mm.
The charge generation and charge transport compositions may be applied to the substrate using any suitable coating technique such as dip-coating, roll-coating, and spray-coating. Any suitable drying method may be used to dry the compositions, such as oven drying, forced air drying, or infrared radiation drying.
Photoconductors in accordance with the invention charge and discharge at a short time interval, such as from about 0.05 to about 0.30 seconds. In one embodiment, a photoconductor having a charge generation layer comprising a binder blend of polyvinylbutyral binder and cyclic carbonate polymer binder exhibits reduced fatigue and/or dark decay as compared to a photoconductor having a charge generation layer comprising the same amount of total binder but wherein the binder comprises polyvinyl butyral binder, in the absence of the cyclic carbonate polymer.
The following examples demonstrate the preparation of cyclic carbonate polymers for use in the invention and demonstrate charge generation layers, photoconductors and methods according to the invention. In the examples and throughout the present specification, parts and percentages are by weight unless otherwise indicated.
Preparatory Example A
Preparation of Phenolic Novolac Cyclic Carbonate Polymer
A phenolic novolac poly(p-octylphenol-formaldehyde) resin (CRJ-418,Mnxcx9c1433, 4.0 g, 18.32 mmol), is placed in a three-neck round bottom flask and dissolved in about 30. grams of tetrahydrofuran (THF), using a magnetic stirrer. The flask is fitted with a dropping funnel and condenser. Pyridine (about 10 drops) is added to the flask. Triphosgene (2.42 g, 9.16 mmol) is weighed into the dropping funnel and dissolved in about 20 ml of THF. The triphosgene/THF solution is added dropwise to a rapidly stirred solution of the phenolic novolac in THF. The light-brown solution turns colorless, with precipitation of pyridinium hydrochloride. Addition is continued over 20 minutes. The white slurry is stirred at xcx9c60xc2x0 C. for 4 hours. The white precipitate is filtered through a fluted filter paper. The filtrate is washed and extracted with water and 1,2-dichloroethane. The colorless organic layer is washed with 5% sodium hydroxide (xcx9c50 ml), and water and dried over anhydrous magnesium sulfate. The organic layer is roto-evaporated to obtain a viscous light yellow-brown oil, which solidifies to a light brown solid. The reaction yields about 4.12 grams of cyclic carbonate polymer having a number average molecular weight (Mn) of about 1917, a polydispersity (Mw/Mn) of about 1.36, and a glass transition temperature of about 96xc2x0 C.
Preparatory Example B
Preparation of Poly(vinylbutyral-vinylacetate-vinylcarbonate)
Poly(vinylbutyral-vinylalcohol-vinylacetate) resin (BX-55Z, S-Lec-B, Sekisui Chemicals, Mnxcx9c98k, Tgxcx9c92xc2x0 C., 4.0 g, 18.32 mmol)) is placed in a three-neck round bottom flask and dissolved in 30 g of THF using a magnetic stirrer. The flask is fitted with a dropping funnel and condenser. Pyridine (about 10 drops) is added to the flask. Triphosgene (2.42 g, 9.16 mmol) is weighed into the dropping funnel and dissolved in about 20 mL of THF. The triphosgene/THF solution is added dropwise to a rapidly stirred solution of the resin in THF. The white precipitate is filtered through a fluted filter paper. The filtrate is washed and extracted with water and 1,2-dichloroethane. The organic layer is roto-evaporated to obtain a viscous light yellow-brown oil, which solidifies to a light brown solid. The yield is about 2.1 grams of cyclic carbonate polymer.

Photoconductors comprising cyclic carbonate polymers


An integrated tool that enables wet chemical processing chambers, lift-rotate units and other hardware to be quickly interchanged without having to recalibrate the transport system or other components to the replacement items. These tools are expected to reduce the down time associated with repairing or maintaining processing chambers and/or lift-rotate units so that the tools can maintain a high throughput. Several aspects of these tools are particularly useful for applications that have stringent performance requirements because components are more likely to require maintenance more frequently, and reducing the down time associated with maintaining such components will significantly enhance the integrated tool.

Microdevices are manufactured by depositing and working several layers of materials on a single substrate to produce a large number of individual devices. For example, layers of photoresist, conductive materials, and dielectric materials are deposited, patterned, developed, etched, planarized, and otherwise manipulated to form features in and/or on a substrate. The features are arranged to form integrated circuits, micro-fluidic systems, and other structures.
Wet chemical processes are commonly used to form features on microfeature workpieces. Wet chemical processes are generally performed in wet chemical processing tools that have a plurality of individual processing chambers for cleaning, etching, electrochemically depositing materials, or performing combinations of these processes. FIG. 1 schematically illustrates an integrated tool 10 that can perform one or more wet chemical processes. The tool 10 includes a housing or cabinet 20 having a platform 22, a plurality of wet chemical processing chambers 30 in the cabinet 20, and a transport system 40. The tool 10 also includes lift-rotate units 32 coupled to each processing chamber 30 for loading/unloading the workpieces W. The processing chambers 30 can be rinse/dry chambers, cleaning capsules, etching capsules, electrochemical deposition chambers, or other types of wet chemical processing vessels. The transport system 40 includes a linear track 42 and a robot 44 that moves along the track 42 to transport individual workpieces W within the tool 10. The integrated tool 10 further includes a workpiece storage unit 60 having a plurality of containers 62 for holding workpieces W. In operation, the robot 44 transports workpieces to/from the containers 62 and the processing chambers 30 according to a predetermined workflow within the tool 10.
One concern of integrated wet chemical processing tools is that the processing chambers must be maintained and/or repaired periodically. In electrochemical deposition chambers, for example, consumable electrodes degrade over time because the reaction between the electrodes and the electrolytic solution decomposes the electrodes. The shape of consumable electrodes accordingly changes causing variations in the electrical field. As a result, consumable electrodes must be replaced periodically to maintain the desired deposition parameters across the workpiece. The electrical contacts that contact the workpiece also may need to be cleaned or replaced periodically. To maintain or repair electrochemical deposition chambers, they are typically removed from the tool 10 and replaced with an extra chamber.
One problem with repairing or maintaining existing wet chemical processing chambers is that the tool must be taken offline for an extended period of time to remove and replace the processing chambers 30 from the tool 10. When the processing chamber 30 is removed from the tool 10, a pre-maintained processing chamber 30 is mounted to the platform 22 at the vacant station, and then the robot 44 and the lift-rotate unit 32 are recalibrated to operate with the new processing chamber. Recalibrating the robot 44 and the lift-rotate unit 32 is a time-consuming process that increases the downtime for repairing or maintaining processing chambers. As a result, when only one processing chamber 30 of the tool 10 does not meet specifications, it is often more efficient to continue operating the tool 10 without stopping to repair the one processing chamber 30 until more processing chambers do not meet the performance specifications. The loss of throughput of a single processing chamber 30, therefore, is not as severe as the loss of throughput caused by taking the tool 10 offline to repair or maintain a single one of the processing chambers 30.
The practice of operating the tool 10 until at least two processing chambers 30 do not meet specifications severely impacts the throughput of the tool 10. For example, if the tool 10 is not repaired or maintained until at least two or three processing chambers 30 are out of specification, then the tool operates at only a fraction of its full capacity for a period of time before it is taken offline for maintenance. This increases the operating costs of the tool 10 because the throughput not only suffers while the tool 10 is offline to replace the wet processing chambers 30 and recalibrate the robot 44, but the throughput is also reduced while the tool is online because it operates at only a fraction of its full capacity. Moreover, as the feature sizes decrease, the electrochemical deposition chambers 30 must consistently meet much higher performance specifications. This causes the processing chambers 30 to fall out of specifications sooner, which results in shutting down the tool more frequently. Therefore, the downtime associated with repairing and/or maintaining electrochemical deposition chambers and other types of wet chemical processing chambers is significantly increasing the cost of operating wet chemical processing tools.

This patent is subject to a terminal disclaimer.

Integrated tool with interchangeable wet processing components for processing microfeature workpieces


Provided are sensors and articles of manufacture comprising one or more sensors. Also provided are uses of the sensors. The sensors have an elastomeric foam and one or more light sources and one or more light receivers. In various examples, the light source(s) and light receiver(s) are disposed on and/or disposed in and/or partially disposed in the elastomeric foam.

Previous sensors do not demonstrate high resolution sensing of haptic input, did not allow for direct control of the shape of a porous structure, or were restricted to particular applications, and the degree of stretching (i.e., strain) and ease of deformation (i.e., compliance) was restricted to low strains or high stiffnesses for many classes of sensors. Therefore, what is needed is an improved sensor.

Sensors with elastomeric foams and uses thereof


Provided is a communication quality measurement method and a portable communication quality measurement device for wireless sensor network configuration. The communication quality measurement method for wireless sensor network configuration includes: a portable communication quality measurement device transmitting a communication quality detection request message to one or more of communication nodes in a wireless sensor network system at a location prepared for new installation; the one or more of the communication nodes in the wireless sensor network system receiving the communication quality detection request message to detect transmission quality information on the communication quality detection request message and adding the detected transmission quality information to a respond message to transmit the respond message to a next communication node; and the portable communication quality measurement device receiving the respond message transceived between the communication nodes to detect reception quality information and displaying the detected reception quality information and transmission quality information included in the respond message.

In general, in order to install a new communication node of a new base station or a device in a wireless sensor network system, only a received signal strength indication (RSSI) of the communication node measured at a corresponding installation location is considered. As described above, conventionally, since only the RSSI of the communication node is considered to install the new communication node in the wireless sensor network system, in some cases, the corresponding installation location may not be appropriate for a communications network of the communication node. For example, in a communication environment with a high RSSI but a low transmitted signal strength indication, normal communications with the newly installed communication node cannot be normally performed.

Method and device of measuring communication quality for constructing wireless sensor network

Gangneung-Wonju National University Academy Cooperation Group


Ultra-high-strength linepipes having excellent low-temperature toughness manufactured by welding together the edges of steel plates comprising C of 0.03 to 0.07 mass %, Si of not more than 0.6 mass %, Mn of 1.5 to 2.5 mass %, P of not more than 0.015 mass %, S of not more than 0.003 mass %, Ni of 0.1 to 1.5 mass %, Mo of 0.15 to 0.60 mass %, Nb of 0.01 to 0.10 mass %, Ti of 0.005 to 0.030 mass %, Al of not more than 0.06 mass %, one or more of required amounts of B, N, V, Cu, Cr, Ca, REM (rare-earth metals) and Mg, with the remainder consisting of iron and unavoidable impurities and having a (Hv-ave)/(Hv-M) ratio between 0.8 and 0.9 at 2.5≦P≦4.0, wherein Hv-ave is the average Vickers hardness in the direction of the thickness of the base metal and Hv-M is the martensite hardness depending on C-content (Hv-M=270+1300C) and a tensile strength TS-C between 900 MPa and 1100 MPa; P=2.7C+0.4Si+Mn+0.8Cr+0.45(Ni+Cu)+(1+β)Mo−1+β (β=1 when B≧3 ppm and β=0 when B<3 ppm).

Recently pipelines have been acquiring increasing importance as long distance transportation means for crude oil, natural gas, etc. Up to now the American Petroleum Institute (API) Standards X80 and below have been applied to long-distance transportation main linepipes. However, higher-strength linepipes are required for (1) the improvement of transportation efficiency through increase of transportation pressure and (2) the improvement of laying efficiency through reduction of linepipe diameter and weight.
Particularly X120 grade linepipes having a tensile strength of 900 MPa or more and being capable of withstanding approximately twice as much internal pressure as X65 can transport approximately twice as much gas as same size linepipes of lower grades. Compared with methods which increase linepipes' pressure carrying capacity by increasing pipe wall thickness, the use of higher-strength linepipes realizes large savings in pipeline construction cost by saving costs of material, transportation and field welding work.
As has been already disclosed in Japanese Unexamined Patent Publication (Kokai) No. 2000-199036, development of X120 linepipes, whose base material microstructure consists principally of a martensite/bainite mixture (lower bainite), is under way. However, the manufacture of this linepipe involves severe process constraints because extremely precise and strict microstructural control is required.
Increasing the strength of linepipes also necessitates increasing the strength of weld metal formed in joints between pipes field-welded (hereinafter referred to as field welds) in pipeline construction.
Generally the low-temperature toughness of the weld metal of welded joints is lower than that of the base metal and decreases further when the strength increases. Therefore, increasing the strength of linepipes necessitates increasing the strength of the weld metal of field welds, which leads to a lowering of low-temperature toughness.
If the strength of the weld metal of field welds is lower than the longitudinal strength of linepipe, strain concentrates in the field welds when stress occurs in the longitudinal direction of pipeline, thereby increasing the fracture susceptibility in heat-affected zone.
In ordinary pipelines, internal pressure generates circumferential stress but develops no longitudinal stress. However, in pipelines built in regions, such as discontinuous tundras, where the ground moves due to the actions of freezing and thawing, the movement of the ground bends pipelines and develops longitudinal stress.
That is, the weld metal of field welds of pipelines must have greater strength than the strength in the longitudinal direction of the pipe. However, the weld metal of field welds of the ultra-high-strength linepipes to which the present invention relates already has high strength. Therefore, further strengthening brings about a sharp decrease in toughness.
Accordingly, this problem will be relieved if the strength in the longitudinal direction of pipe that has no relation to the strength to withstand internal pressure is decreased while maintaining the strength in the circumferential direction of pipe.
The high-strength steel pipe the inventor proposed in Japanese Unexamined Patent Publication (Kokai) No. 2004-052104 differs in microstructure from the pipe according to this invention. This structural difference is due to differences in the amount of processing in the uncrystallized region and manufacturing conditions.

Steel plates for ultra-high-strength linepipes and ultra-high-strength linepipes having excellent low-temperature toughness and manufacturing methods thereof


The emergency alert service responds to receipt of emergency alert messages by filtering, formatting and routing emergency alert information to a variety of different networked appliances and also to remote devices. In this way, a consistent warning message is disseminated simultaneously over many different warning systems, thus increasing warning effectiveness while simplifying the warning task. The system thus provides a common alerting protocol that is simple but quite robust and capable of exchanging all-hazard emergency alerts and public warnings over all kinds of networks.

The present invention relates generally to facilities for providing emergency alert messages over public broadcast and other information dissemination systems. More particularly, the invention relates to an improved emergency alert system that integrates with network-attached appliances in local area network and home network environments to facilitate delivery of the emergency alert message even when the emergency alert monitor system is turned off or in sleep mode.
The Federal Communications Commission (FCC) currently mandates support for Emergency Alert Messages (EAM) in receivers. In analog systems, the emergency alert message is typically embedded in the signal itself. In digital systems the emergency alert messages are typically sent via the in-band transport stream. In the cable environment, emergency alert messages may also be carried in the out-of-band (OOB) channel.
Currently, once an emergency alert message is received by a receiver (analog or digital) it is decoded and annunciated. Where a display monitor is provided, annunciation of the message may be as a displayed text message. Where an audio monitor is provided, the message annunciation may be provided in audio form. In either case, however, if the monitor happens to be switched off at the time the emergency alert message is received, the message is lost. For example, if an emergency alert message is broadcast for display on a consumer's television set, and that television set is switched off, the consumer does not receive the alert message.
There are also some types of receiver equipment that employ a power saving mode or standby mode. When such a receiver is in such power saving mode or standby mode, the emergency alert message is likewise not received. Currently there is no mechanism to notify the user or consumer when such messages are broadcast but not received.

Matsushita Electric Industrial Co., Ltd.


A device (1) for varying the control times of an internal combustion engine (100) is provided. A device (1) is proposed, with a means for limiting the angle of rotation, this being optimized in terms of the magnitude of the transmittable forces. A further aspect of the invention relates to making the mounting of the device (1) more flexible to the effect that the same components can be used in devices (1) with different relative angle-of-rotation ranges.

In internal combustion engines, camshafts are used for actuating the gas exchange valves. Camshafts are mounted in the internal combustion engine in such a way that cams attached to them bear against cam followers, for example bucket tappets, drag levers or rocker arms. When the camshaft is set in rotation, the cams roll on the cam followers which in turn actuate the gas exchange valves. Thus, owing to the position and shape of the cams, both the opening duration and amplitude, but also the opening and closing time point of the gas exchange valves are defined.
Modern engine concepts tend toward a variable design of the valve drive. On the one hand, the valve stroke and valve opening duration are to be capable of being configured variably up to the complete cut-off of individual cylinders. For this purpose, concepts, such as switchable cam followers, variable valve drives or electro-hydraulic or electric valve actuations, are provided. Furthermore, it has proved advantageous to be able to exert influence on the opening and closing times for the gas exchange valves while the internal combustion engine is in operation. It is likewise desirable to be able to influence the opening and closing time points of the inlet and outlet valves separately so that, for example, a defined valve overlap can be set in a directed way. By the opening and closing time points of the gas exchange valves being set as a function of the current characteristic map range of the engine, for example of the current rotational speed or the current load, the specific fuel consumption can be lowered, the exhaust gas behavior can be influenced positively and the engine efficiency, maximum torque and maximum power can be increased.
The variability in the gas exchange valve time control, as described, is brought about by means of a relative change in the phase position of the camshaft with respect to the crankshaft. In this case, the camshaft is mostly drive-connected to the crankshaft via a chain, belt or gearwheel mechanism or identically acting drive concepts. Between the chain, belt or gearwheel mechanism driven by the crankshaft and the camshaft is mounted a camshaft adjuster which transmits the torque from the crankshaft to the camshaft. In this case, this device for varying the control times of the internal combustion engine is designed in such a way that, while the internal combustion engine is in operation, the phase position between the crankshaft and camshaft can be maintained reliably, and, if desired, the camshaft can be rotated within a certain angular range with respect to the crankshaft.
In internal combustion engines with a camshaft in each case for the intake and the exhaust valves, these may be equipped in each case with a camshaft adjuster. As a result, the opening and closing times of the intake and exhaust gas exchange valves can be displaced relative to one another in time and the valve time overlaps can be set in a directed way.
The seat of modern camshaft adjuster is generally located at the drive-side end of the camshaft. It consists of a crankshaft-fixed driving wheel, of a camshaft-fixed driven element and of an adjusting mechanism transmitting the torque from the driving wheel to the driven part. The driving wheel may be designed as a chain wheel, belt wheel or gearwheel and is connected fixedly in terms of rotation to the crankshaft by means of a chain, a belt or a gearwheel mechanism. The adjusting mechanism may be operated electromagnetically, hydraulically or pneumatically. It is likewise conceivable to attach the camshaft adjuster to an intermediate shaft or to mount it on a nonrotating component. In this case, the torque is transmitted to the camshafts via further drives.
Electrically operated camshaft adjusters consist of a driving wheel which is drive-connected to the crankshaft of the internal combustion engine, of a driven part which is drive-connected to a camshaft of the internal combustion engine and of an adjusting mechanism. The adjusting mechanism is a three-shaft mechanism with three components rotatable with respect to one another. In this case, the first component of the mechanism is connected fixedly in terms of rotation to the driving wheel and the second component is connected fixedly in terms of rotation to the driven part. The third component is designed, for example, as a toothed component, the rotational speed of which can be regulated via a shaft, for example by means of an electric motor or a braking device.
The torque is transmitted from the crankshaft to the first component and from there to the second component and consequently to the camshaft. This takes place either directly or with the third component being interposed.
By the rotational speed of the third component being suitably regulated, the first component can be rotated with respect to the second component, and consequently the phase position between the camshaft and crankshaft can be varied. Examples of three-shaft mechanisms of this type are inner eccentric mechanisms, double inner eccentric mechanisms, harmonic drives, swashplate mechanisms or the like.
To control the camshaft adjuster, sensors detect the characteristic data of the internal combustion engine, such as, for example, the load state, the rotational speed and the angular positions of the camshaft and crankshaft. These data are fed to an electronic control unit which, after comparing the data with a characteristic map of the internal combustion engine, controls the adjusting motor of the camshaft adjuster.
DE 102 36 507 discloses a device for varying the control times of an internal combustion engine, in which torque transmission from the crankshaft to the camshaft and the adjusting operation are implemented by means of a swashplate mechanism. The device consists essentially of a camshaft wheel, of a camshaft-fixed rotary disk and of a swashplate mechanism. The camshaft wheel is drive-connected to a crankshaft and is produced in one piece with a housing. The swashplate is mounted on an adjusting shaft at a defined angle of incidence and is drive-connected to the housing.
The swashplate and the rotary disk are provided, on their axial side faces in each case facing the other component, in each case with a bevel wheel toothing in the form of a toothed rim. In this case, the swashplate and the rotary disk are arranged in such a way that, because of the mounting of the swashplate on the adjusting shaft at a specific angle of incidence, an angular segment of the toothing of the swashplate engages into an angular segment of the toothing of the rotary disk. There is, in this case, a difference in the number of teeth of the bevel wheel toothings.
The adjusting shaft is drive-connected to a drive unit, for example an electric motor, which drives it at a continuously regulatable rotational speed. A rotation of the adjusting shaft in relation to the rotary disk leads to a wobbling rotation of the swashplate and consequently to a rotation of the engaged angular segment in relation to the rotary disk and to the swashplate. On account of the different number of teeth of the bevel wheel toothings, this leads to a relative rotation of the camshaft with respect to the crankshaft.
If the amount of the relative angle of rotation between the camshaft and crankshaft overshoots a specific value, the internal combustion engine can no longer operate reliably. In the event of an extreme offset, the pistons may knock against the open gas exchange valves, thus leading to engine damage. Phase positions of this kind may occur, for example, due to a failure of the control unit or of the drive of the adjusting shaft or in the case of damage to the device itself. In order to prevent the offset between the angle of rotation of the crankshaft and the angle of rotation of the camshaft from becoming too great, means are provided for limiting the relative angle of rotation of the camshaft with respect to the crankshaft. For this purpose, the rotary disk connected at the camshaft is provided with a clearance, into which a stop arranged on the camshaft wheel engages. The stop may be produced in one piece with the camshaft wheel or be fastened to the latter.
This embodiment has the disadvantage that the stop has to be designed with a very high mass in order to withstand the high forces occurring in the event of a malfunction of the device. This leads to a large mass of the device and to high production costs. Furthermore, this principle proves to be inflexible in terms of the manufacture of various devices having different adjustment angle ranges.

Device for modifying the control times of an internal combustion engine


A method of driving a plasma display panel including (A) a first substrate including a first electrode, and a second electrode extending in parallel with the first electrode and defining a display area with the first electrode therebetween, and (B) a second substrate including a third electrode facing the first and second electrodes and extending perpendicularly to the first and second electrodes, includes (a) applying a serrate voltage having an inclined waveform in which a voltage varies with the lapse of time, to the first and/or second electrodes, and (b) applying a preliminary charge-eliminating pulse voltage to the first and/or second electrodes after the a charge-eliminating discharge has been generated due to the serrate voltage, wherein the preliminary charge-eliminating pulse voltage eliminates electric charges only when electric charges have not been sufficiently eliminated.

1. Field of the Invention
The invention relates to a method of driving a plasma display panel, and more particularly to a method of driving an AC memory-operation type plasma display panel.
2. Description of the Related Art
A plasma display panel is structurally grouped into a DC (direct current) type panel having electrodes exposed to discharge gas, and an AC (alternating current) type panel having electrodes covered with a dielectric layer to prevent from being directly exposed to discharge gas. An AC type plasma display panel is further structurally grouped into a memory-operation type panel which operates by virtue of a memory function caused by a function of a dielectric layer to store electric charges therein, and a refresh-operation type panel which operates not using a memory function.
Hereinbelow are explained a structure of an AC memory-operation type plasma display panel and a method of driving the same.
FIG. 1 is a perspective broken view of a conventional AC type plasma display panel suggested in Japanese Patent Application Publication No. 2001-272948.
As illustrated in FIG. 1, a plasma display panel 20 includes an electrically insulating front substrate 1A and an electrically insulating rear substrate 1B.
On the front substrate 1A are arranged a scanning electrode 9 and a common electrode 10 spaced away from each other and in parallel with each other.
Each of the scanning electrode 9 and the common electrode 10 is comprised of a bus electrode 3 for presenting electrical conductivity, and a principal discharge electrode 2 formed on the bus electrode 3 for generating discharge therefrom. The principal discharge electrode 2 in the plasma display panel 20 is comprised of a transparent electrode composed of indium-tin oxide (ITO) or SnO2 for preventing reduction in light transmissivity.
The scanning electrode 9 and the common electrode 10 are covered with a dielectric layer 4a, which is covered with a protection film 5 composed of magnesium oxide to protect the dielectric layer 4a from discharges.
On the rear substrate 1B is arranged a plurality of data electrodes 6 extending in parallel with one another and perpendicularly to the scanning electrode 9 and the common electrode 10.
The data electrodes 6 are covered with a dielectric layer 4b. On the dielectric layer 4b is formed a plurality of partition walls 7 extending in parallel with the data electrodes 6 for defining discharge areas and display cells.
A phosphor layer 8 is formed on an exposed surface of the dielectric layer 4b and sidewalls of the partition walls 7 for converting ultra-violet rays generated by discharges, into visible light. By forming color phosphor layers in each of display cells, it would be possible to display colored images. For instance, color phosphor layers of three primary colors, that is, red (R), green (G) and blue (B) may be formed.
Discharge gas is introduced into a space sandwiched between the front and rear substrates 1A and 1B and partitioned by the partition walls 7. For instance, discharge gas is comprised of helium (He), neon (Ne) and xenon (Xe) alone or in combination.
FIG. 2 is a plan view of the plasma display panel 20 as viewed from a viewer.
As illustrated in FIG. 2, the scanning electrode 9 and the common electrode 10 extend in a row direction in parallel with each other. A gap formed between the scanning electrode 9 and the common electrode 10 is called a discharge gap 12, in which surface-discharge is generated between the scanning electrode 9 and the common electrode 10.
Hereinbelow, a method of driving the plasma display panel 20 is explained with reference to FIG. 3.
FIG. 3 is a timing chart showing waveforms of pulse voltages applied to the scanning electrode 9, the common electrode 10 and the data electrode 6, and further showing waveforms of a light emitted in normal operation and at generation of intensive discharge.
It is assumed in FIG. 3 that the previous sub-field is selected, but the illustrated sub-field is not selected.
Voltages are applied separately to each of the scanning and data electrodes 9 and 6, and voltages having a common waveform are applied to all of the common electrodes 10.
As illustrated in FIG. 3, a fundamental cycle for driving the plasma display panel 20 includes a reset period (A) in which display cells are reset for causing discharges to be readily generated in the subsequent period (B), a scanning period (B) in which it is selected which display cell or cells is(are) to be turned on or off, a sustaining period (C) in which discharges are generated in all of the selected display cells. Such a fundamental cycle is called a sub-field.
In the reset period, a sustaining-discharge eliminating pulse Pse is applied to all of the scanning electrodes 9 to generate charge-eliminating discharge to eliminate wall charges accumulated due to previous sustaining-discharge pulses.
Herein, the term "eliminate" should not be limited to elimination of all of wall charges, but should be interpreted as including reduction in wall charges for smoothly generating subsequent preliminary discharges, data-writing discharges and sustaining discharges.
The sustaining-discharge eliminating pulse Pse is a pulse voltage having an inclined waveform or a serrate waveform in which a voltage varies with the lapse of time.
Then, a positive priming pulse Pp+ is applied to all of the scanning electrodes 9 for causing compulsory discharges in all of the display cells. While the positive priming pulse Pp+ is being applied to the scanning electrode 9, a negative priming pulse Pp− is applied to the common electrodes 10.
Then, a priming-eliminating pulse Ppe is applied to all of the scanning electrodes 9 for causing charge-eliminating discharges to eliminate wall charges having been accumulated due to the positive priming pulse Pp+. The term "eliminate" should not be limited to elimination of all of wall charges, but should be interpreted as including reduction in wall charges for smoothly generating subsequent data-writing discharges and sustaining discharges.
Preliminary discharge caused by application of the positive priming pulse Pp+ and elimination of the preliminary discharge caused by application of the priming-eliminating pulse Ppe make subsequent data-writing discharge be readily generated.
Following the priming-eliminating pulse Ppe, a scanning base pulse Pbw is applied to the scanning electrode 9.
The positive priming pulse Pp+ and the priming-eliminating pulse Ppe have an inclined waveform or a serrate waveform in which a voltage raises or lowers with the lapse of time. Discharge generated by application of a voltage having such an inclined waveform is just weak discharge which can extend only in the vicinity of the discharge gap 12.
The above-mentioned preliminary discharge and charge-eliminating discharge are generated independently of images. Hence, light emission caused by those discharges is observed as background luminance. If the thus observed background luminance is at high level, contrast would be deteriorated, and hence, quality of images is degraded.
An operation of the plasma display panel 20 caused by the sustaining-discharge eliminating pulse Pse in a cross-section A1–A2 (see FIG. 2) of the data electrode 6 in a display cell is explained hereinbelow with reference to FIG. 4 and FIGS. 5A to 5E.
FIG. 4 illustrates the sustaining-discharge eliminating pulse Pse over a sustaining period to the next reset period, and FIGS. 5A to 5E illustrate wall charges in a reset period in the case that weak discharges are stably generated.
In a conventional method of driving the plasma display panel 20, a voltage Vs is applied to the scanning electrode 9, and the common electrode 10 is grounded at a final sustaining discharge in a sustaining period.
Thus, as illustrated in FIG. 5A, negative electric charges are accumulated on the dielectric layer 4a above the scanning electrode 9 and positive electric charges are accumulated on the dielectric layer 4a above the common electrode 10 immediately before application of the sustaining-discharge eliminating pulse Pse and after sustaining discharge was generated. In contrast, positive electric charges are accumulated on the dielectric layer 4b above the data electrode 6, as illustrated in FIG. 5A.
During the application of the sustaining-discharge eliminating pulse Pse to the scanning electrode 9, the common electrode 10 is kept at the voltage Vs, and a voltage having an inclined or serrate waveform in which a voltage gradually varies to GND from the voltage Vs with the lapse of time is applied to the scanning electrode 9 (hereinbelow, such a voltage is referred to as "a serrate voltage"). After the application of the serrate voltage, when a sum of a voltage externally applied to the electrodes 9 and 10 and a voltage caused by wall charges exceeds a threshold voltage at which discharge starts, surface-discharge is generated between the scanning electrode 9 and the common electrode 10.
The surface electrode starts at a time Tfsw (see FIG. 4). If the serrate voltage has an inclination of about 10V/microsecond or smaller, the surface-discharge is generated as weak discharge gradually expanding as the serrate voltage varies, as illustrated in FIG. 5B.
As illustrated in FIG. 5C, weak discharge is generated between the scanning electrode 9 and the common electrode 10 further at a time Tfss (see FIG. 4).
When a sum of a voltage externally applied to the electrodes 9 and 6 and a voltage caused by wall charges exceeds a threshold voltage at which discharge starts, cross-discharge is generated between the scanning electrode 9 and the data electrode 6 wherein the data electrode 6 is at a positive voltage and the scanning electrode 9 is at a negative voltage. The cross-discharge starts at a time Tfm (see FIG. 4).
As shown in FIG. 4, the time Tfsw is earlier than the time Tfm at which the cross-discharge is generated between the scanning electrode 9 and the data electrode 6. That is, since the surface-discharge has been generated between the scanning electrode 9 and the common electrode 10, ions and metastables already exist in a discharge space, namely, the discharge space is already activated. Accordingly, the cross-discharge is stably generated between the scanning electrode 9 and the data electrode 6, as illustrated in FIG. 5D.
After the application of the sustaining-discharge eliminating pulse Pse to the scanning electrode 9, electric charges are accumulated as illustrated in FIG. 5E.
An operation of the plasma display panel 20 caused by the priming-eliminating pulse Ppe is explained hereinbelow with reference to FIG. 6 and FIGS. 7A to 7D.
FIG. 6 illustrates waveforms of the positive priming pulse Pp+ and the priming-eliminating pulse Ppe, and FIGS. 7A to 7D illustrate wall charges in a reset period.
While the positive priming pulse Pp+ having an inclined waveform is applied to the scanning electrode 9, the common electrode 10 is kept at GND.
When a sum of a voltage externally applied to the electrodes 9 and 10 and a voltage caused by wall charges exceeds a threshold voltage at which discharge starts, surface-discharge is generated between the scanning electrode 9 and the common electrode 10. The surface-discharge is generated as weak discharge gradually expanding as the serrate voltage varies, similarly to discharge generated by the application of the sustaining-discharge eliminating pulse Pse to the scanning electrode 9. The surface-discharge rearranges electric charges existing in the vicinity of the discharge gap 12.
At the same time, cross-discharge is generated between the scanning electrode 9 and the data electrode 6, resulting in that positive electric charges are accumulated on the dielectric layer 4b above the data electrode 6.
After the application of the positive priming pulse Pp+ to the scanning electrode 9 has been terminated, as illustrated in FIG. 7A, negative electric charges are accumulated on the dielectric layer 4a above the scanning electrode 9, positive electric charges are accumulated on the dielectric layer 4a above the common electrode 10, and positive electric charges are accumulated on the dielectric layer 4b above the date electrode 6.
While the priming-eliminating pulse Ppe having a negatively inclined waveform is applied to the scanning electrode 9, the common electrode 10 is kept at the voltage Vs.
After the application of the priming-eliminating pulse Ppe to the scanning electrode 9, when a sum of a voltage externally applied to the electrodes 9 and 10 and a voltage caused by wall charges exceeds a threshold voltage at which discharge starts, surface-discharge is generated between the scanning electrode 9 and the common electrode 10. The surface-discharge starts at a time Tfsw (see FIG. 4). The surface-discharge is generated as weak discharge gradually expanding as the serrate voltage varies, as illustrated in FIG. 7B.
When a sum of a voltage externally applied to the electrodes 9 and 6 and a voltage caused by wall charges exceeds a threshold voltage at which discharge starts, cross-discharge is generated between the scanning electrode 9 and the data electrode 6. The cross-discharge starts at a time Tfm (see FIG. 4).
Weak discharge is generated between the scanning electrode 9 and the common electrode 10 also at a time Tfss (see FIG. 6)
The time Tfsw at which the surface-discharge is generated between the scanning electrode 9 and the common electrode 10 is earlier than the time Tfm at which the cross-discharge is generated between the scanning electrode 9 and the data electrode 6. That is, when the cross-discharge is generated between the scanning electrode 9 and the data electrode 6, the surface-discharge has been already generated between the scanning electrode 9 and the common electrode 10, as illustrated in FIGS. 7B and 7C.
After the application of the priming-eliminating pulse Ppe to the scanning electrode 9 has been terminated, electric charges are arranged such that operation in the subsequent scanning period can be smoothly carried out, as illustrated in FIG. 7D. That is, negative electric charges are accumulated on the dielectric layer 4a above the scanning electrode 9, positive electric charges are accumulated on the dielectric layer 4a above the common electrode 10, and positive electric charges are accumulated on the dielectric layer 4b above the data electrode 6.
When not selected in the subsequent scanning period, that is, when data-writing discharge is not generated, wall charges are reduced to such a degree that discharge is not generated in a sustaining period.
In a scanning period in which discharge is generated to select a display cell in which a light is to be emitted, a scanning pulse Pw is applied to the scanning electrodes 9 one by one at different timings from one another, and a data pulse Pd having a voltage Vd is applied to the data electrode 6 in accordance with images to be displayed and in synchronization with a timing at which the scanning pulse was applied. The voltage Vd is equal to about 70V, for instance. In a display cell in which while the scanning pulse Pw is applied to scanning electrode 9, the data pulse Pd is applied to the data electrode 6, cross-discharge is generated between the scanning electrode 9 and the data electrode 6, and the cross-discharge induces surface-discharge to be generated between the scanning electrode 9 and the common electrode 10. A series of these actions is called data-writing discharge.
As a result of the generation of the data-writing discharge, positive electric charges are accumulated on the dielectric layer 4a above the scanning electrode 9, negative electric charges are accumulated on the dielectric layer 4a above the common electrode 10, and negative electric charges are accumulated on the dielectric layer 4b above the data electrode 6.
As a result of first sustaining-discharge, negative electric charges are accumulated on the dielectric layer 4a above the scanning electrode 9, and positive electric charges are accumulated on the dielectric layer 4a above the common electrode 10.
In a second sustaining-pulse, a voltage has a polarity opposite to a polarity of a voltage to be applied to the scanning electrode 9 and the common electrode 10 in accordance with a first sustaining-pulse. Hence, a voltage caused by electric charges accumulated on the dielectric layer 4a is added to a voltage in the second sustaining-pulse, and accordingly, there is generated second sustaining-discharge.
Hereinafter, sustaining-discharges are generated in the same way. If surface-discharge is not generated by virtue of the first sustaining-pulse, discharge will not be generated due to subsequent sustaining-pulses.
A combination of the above-mentioned reset period, scanning period and sustaining period is called a sub-field.
In order to accomplish displaying images at gray scales, one field which is a period for displaying one scene is divided into a plurality of sub-fields, and the different number of sustaining-pulses is assigned to each of sub-fields. If one field is divided into N sub-fields, and a luminance ratio among the sub-fields is defined equal to 2(N−1), it would be possible to display images at 2N gray scales by selecting sub-fields to be displayed in a field and combining them with one another.
For instance, it is assumed that one field is divided into eight (8) sub-fields. Since the eighth power of two is equal to 256 (28=256), it is possible to display images at 256 gray scales by controlling on/off of each of the eight sub-fields.
The above-mentioned conventional method of driving the plasma display panel 20 is accompanied with problems that weak discharge is not generated, but intensive discharge is generated at a voltage beyond a voltage at which weak discharge is to be generated, in a pulse having an inclined waveform in which a voltage gradually varies with the lapse of time, and that there is generated a difference in a panel in intensity of weak discharges, and resultingly, wall charges are not arranged uniformly in the panel.
FIG. 8 illustrates electric lines of force in an electric field generated between the scanning electrode 9 and the common electrode 10. The reason for the above-mentioned problems is explained hereinbelow with reference to FIG. 8.
As shown with electric lines of force in FIG. 8, an electric field generated between the scanning electrode 9 and the common electrode 10 is curved about the discharge gap 12 as a center. Hence, the electric filed has a relatively small density in an area remote from the discharge gap 12, whereas the electric field has a relatively high density in an area close to the discharge gap 12. Accordingly, a remarkably intensive electric field is generated at the discharge gap 12.
FIGS. 9A to 9E illustrate arrangement of wall charges in a reset period in the case that there is generated intensive discharge.
In the conventional method of driving the plasma display panel 20, the voltage Vs is applied to the scanning electrode 9, and the common electrode 10 is kept at GND when final sustaining-discharge is generated in a sustaining period.
Accordingly, after the generation of the sustaining-discharge has been terminated and immediately before the sustaining-discharge eliminating pulse Pse is applied to the scanning electrode 9, negative electric charges are accumulated on the dielectric layer 4a above the scanning electrode 9, positive electric charges are accumulated on the dielectric layer 4a above the common electrode 10, and positive electric charges are accumulated on the dielectric layer 4b above the data electrode 6, as illustrated in FIG. 9A.
If an efficiency at which discharge is generated is lowered at the application of the sustaining-discharge eliminating pulse Pse, surface-discharge is not accidentally generated at the time Tfsw (see FIG. 9B), but is sometimes generated at a time later than the time Tfsw.
If surface-discharge is generated between the scanning electrode 9 and the common electrode 10 at a time later than the time Tfsw, a voltage difference higher than a voltage difference found at a time at which discharge should start is applied across the scanning electrode 9 and the common electrode 10, because a voltage in a pulse having an inclined waveform is lowered during the time Tfsw to the time at which surface-discharge is actually generated. As a result, the resultant surface-discharge expands to a higher degree than weak discharge, that is, there is generated discharge slightly more intensive than expected.
As mentioned above, a remarkably intensive electric field is generated at the discharge gap 12 formed between the scanning electrode 9 and the common electrode 10. Hence, if there is generated discharge slightly more intensive than expected, the discharge swiftly grows into intensive discharge which expands all over a display cell, as illustrated in FIG. 9C.
The time Tfss shown in FIG. 4 is an earliest time at which such intensive discharge may be generated.
If intensive discharge is generated, positive electric charges are accumulated entirely on the dielectric layer 4a above the scanning electrode 9, and negative electric charges are accumulated entirely on the dielectric layer 4a above the common electrode 10, as illustrated in FIG. 9D.
Hereinafter, since discharge is never generated during application of a pulse voltage having an inclined waveform, to the scanning electrode 9, wall charges are arranged as illustrated in FIG. 9E after the application of the sustaining-discharge eliminating pulse Pse. That is, positive electric charges are accumulated on the dielectric layer 4b above the data electrode 6, but positive electric charges are accumulated on the dielectric layer 4a above the scanning electrode 9, and negative electric charges are accumulated on the dielectric layer 4a above the common electrode 10, contrary to the arrangement of wall charges illustrated in FIG. 5E.
After the application of the sustaining-discharge eliminating pulse Pse to the scanning electrode 9, wall charges are re-arranged by the positive priming pulse Pp+ and the priming-eliminating pulse Ppe. Arrangement of wall charges by the pulses Pp+ and Ppe is accomplished by generating weak discharge, similarly to the sustaining-discharge eliminating pulse Pse. Hence, influence caused by intensive discharge generated when the sustaining-discharge eliminating pulse Pse is applied to the scanning electrode 9 can be eliminated in the vicinity of the discharge gap 12. However, it will be impossible to eliminate such influence all over a display cell. In particular, in an area remote from the discharge gap 12, positive electric charges remain accumulated on the dielectric layer 4a above the scanning electrode 9, and negative electric charges remain accumulated on the dielectric layer 4a above the common electrode 10.
In a subsequent scanning period, voltages applied to the electrodes 9 and 10 are determined such that the plasma display panel can stably operate when negative electric charges are accumulated on the dielectric layer 4a above the scanning electrode 9, and positive electric charges are accumulated on the dielectric layer 4a above the common electrode 10 (see FIG. 5E). Accordingly, if positive electric charges are accumulated on the dielectric layer 4a above the scanning electrode 9, and negative electric charges are accumulated on the dielectric layer 4a above the common electrode 10, the plasma display panel operates unstably.
In order to reduce a background luminance, the positive priming pulse Pp+ and the priming-eliminating pulse Ppe are not sometimes applied to the scanning electrode 9 in a certain sub-field. This is because it is possible to arrange wall charges similarly to the arrangement of wall charges found after the application of the priming-eliminating pulse Ppe, even after wall charges have been arranged by the sustaining-discharge eliminating pulse Pse. Hence, the plasma display panel can operate stably in a subsequent scanning period in the same way as a case in which the positive priming pulse Pp+ and the priming-eliminating pulse Ppe are applied to the scanning electrode 9.
However, if there is generated intensive discharge in the sustaining-discharge eliminating pulse Pse, positive electric charges are accumulated on the dielectric layer 4a above the scanning electrode 9, and negative electric charges are accumulated on the dielectric layer 4a above the common electrode 10, as illustrated in FIG. 9E. Since a subsequent scanning period starts in such a condition, there is caused erroneous light-emission, that is, light is emitted even in a non-selected display cell.
In addition, if positive electric charges accumulated on the dielectric layer 4a above the scanning electrode 9 and negative electric charges accumulated on the dielectric layer 4a above the common electrode 10 are not sufficiently eliminated, there is generated intensive discharge 30B (see FIG. 3) as erroneous discharge in a sustaining period, or the priming-eliminating pulse Ppe causes intensive discharge, and accordingly, there is generated intensive discharge 30B (see FIG. 3) as erroneous discharge in a sustaining period.
In order to prevent such erroneous light-emission, it is necessary to prevent generation of intensive discharge in the sustaining-discharge eliminating pulse Pse. If it is not possible to prevent generation of such intensive discharge, it would be necessary to prepare a countermeasure to such intensive discharge.
If an efficiency at which discharges are generated in the priming-eliminating pulse Ppe, similarly to the sustaining-discharge eliminating pulse Pse, weak discharge may not be generated between the scanning electrode 9 and the common electrode 10.
If discharge is generated later, the resultant discharge would be more intensive than weak discharge because of a higher voltage difference than a voltage difference found at a time at which discharge should start is applied across the scanning electrode 9 and the common electrode 10. Since a remarkably intensive electric field is generated at the discharge gap 12 formed between the scanning electrode 9 and the common electrode 10, the discharge swiftly grows into intensive discharge 30A (see FIG. 3) which expands all over a display cell. The time Tfss shown in FIG. 6 is an earliest time at which such intensive discharge 30A is generated.
The generation of intensive discharge results in that positive electric charges are accumulated entirely on the dielectric layer 4a above the scanning electrode 9, and negative electric charges are accumulated entirely on the dielectric layer 4a above the common electrode 10. This is the same arrangement of wall charges as the arrangement found after data-writing discharge has been generated in a selected display cell in a scanning period.
Accordingly, even if not selected in a subsequent scanning period, if intensive discharge 30A is generated in the priming-eliminating pulse Ppe, there would be generated discharge because of addition of wall charges to an externally applied voltage when a first sustaining-pulse Ps is applied to the electrodes. Discharges are continuously generated even in second and later sustaining pulses Pse.
As a result, there is caused erroneous light-emission, that is, light is emitted even in a non-selected display cell. In order to prevent such erroneous light-emission, it would be necessary to prevent generation of the intensive discharge 30A in the priming-eliminating pulse Ppe, or to eliminate influence exerted by the intensive discharge 30A, even if the intensive discharge 30A was generated.
As explained above, the conventional method of driving the plasma display panel 20 is accompanied with a problem that images are deteriorated as a result that light is emitted in a non-selected display cell, namely, there occurs erroneous light-emission.
For instance, Japanese Patent Application Publication 2000-122602 has suggested a method of driving a plasma display panel which method is capable of solving a problem of erroneous light-emission.
Specifically, in the suggested method, surface-discharge and cross-discharge in charge-eliminating discharge are generated temporally separately from each other.
However, the suggested method is accompanied with a problem that if the discharges are concurrently generated, it would be quite difficult to control electric charges accumulated above a data electrode with the result of erroneous operation in a scanning period.
Specifically, if a ratio at which discharges are generated is quite low, priming particles are soon reduced when a certain period of time passes after generation of discharge. Accordingly, if surface-discharge and cross-discharge are generated temporally separately from each other as in the above-mentioned method, even if cross-discharge is first generated as weak discharge, subsequent surface-discharge will be generated as intensive discharge.
Thus, even in the above-mentioned method, the problem that light is emitted in a non-selected cell due to intensive discharge is not always solved.


A surgical operation support system includes: a surgical instrument provided with a usage count accumulation portion that includes a moving portion and a moving mechanism which is configured to move the moving portion; and a body which includes a driving portion that is configured to move the moving portion through the moving mechanism. The usage count accumulation portion is configured to accumulate a usage count of the surgical instrument by a movement of the moving portion.

Field of the Invention
The present invention relates to a surgical operation support system on which a surgical instrument is mounted for use, and to a surgical instrument which is used for the surgical operation support system.
Description of Related Art
In recent years, in order to reduce invasiveness in surgical operations, robots have been introduced for studying medical treatment and in clinical field. Particularly, in the field of surgery, various medical manipulator systems (surgical operation support systems) which treat a patient by a multi-degrees-of-freedom manipulator including a multi-degrees-of-freedom arm have been suggested. In this medical manipulator system, various surgical instruments such as a gripper (a gripping portion) and forceps, or the like are mounted on the tip of the arm. These surgical instruments have been disposed. However, in recent years, by performing treatment such as sterilization, or the like, it has been possible to use the same surgical instruments more than once by mounting on the tip of the arm. However, these surgical instruments are members deteriorating as they are used more than once, and there is a possibility that the deterioration will cause problems in using the instruments. In order to prevent the problems, it is necessary to use the surgical instrument with the accurate ascertainment of the use limit (life) of the surgical instrument mounted on the tip of the arm.
U.S. Pat. No. 6,331,181 discloses a configuration in which the usage count or the like of a surgical instrument can be recorded by mounting a memory on the surgical instrument. In this configuration, when the surgical instrument is mounted on the arm, the usage count of the surgical instrument that is recorded in the memory can be read.

Surgical operation support system and surgical instrument


A network device for maintaining a communication network is provided. The network device includes a transceiver configured for operable communication with at least one device. The network device also includes a processor including a memory configured to store computer-executable instructions. When executed by the processor the instructions cause the network device to store a plurality of network capabilities associated with a plurality of connectivity categories and a plurality of network settings, receive, from a first device, a connectivity advertisement including at least one connectivity category for the first device, retrieve a subset of the plurality of network capabilities based on the at least one connectivity category, determine one or more network settings for the network device based on the at least one connectivity category for the first device and the subset of network capabilities, and implement the one or more network setting on the network device.

The field of the invention relates generally to managing computer networks, and more specifically, to systems and methods for on-boarding new devices and managing resource allocation for devices on the network.
When new devices are added to a network, the network configuration needs to be updated to manage the new devices. Furthermore, many times the network device running the network does not know what the individual device is capable of. In many cases, the user has adjust network settings to use many of the features of any new device on the network. Accordingly, it would be advisable to simplify the set-up of network devices from the point of view of the user.
Furthermore, when there are multiple devices on a network simultaneously, different devices may see different levels of performance. This can cause issues where different devices require different amounts of resources at different times to work properly. It would be helpful to coordinate the allocation of resources, such as bandwidth, to different devices.

Systems and methods for managing networks for improved device connectivity