Matsushita Electric Industrial Co., Ltd.

Kazuhisa Morimoto

Jinsei Miyazaki

Eiji Ando

Yoshinobu Murakami

Kimiaki Yoshino

Masahide Tsukamoto

Tetsuro Ohtsuka

Shoichi Ishihara

Tetsu Ogawa

Hideo Hatanaka

Yoshihiro Matsuo

Seiichi Nagata

Yoshio Enoki

Takashi Wakabayashi

Akira Minobe

Makoto Kuroda

An optical recording medium which comprises a substrate and a recording layer of at least two J-aggregates of dyes formed on the substrate is described. The dyes may be photochromic dyes or other types of dyes capable of forming the aggregates which have narrower absorption spectral ranges than original dyes. A plurality of information bits can be written in the recording layer by irradiation of one laser beam spot. The recording layer is formed by an LB film method or a method capable of fluidizing a dye solution in a direction horizontal to the substrate surface. A recording method using the medium is also described.

Method for recording optical information in optical high density

An optical recording medium is prepared by the use of spiropyrane whose molecular structure contains an alkyl chain having at least 10 more carbon atoms, and by the use of an LB film method or a spin coating method. This recording medium is of a structure wherein when irradiated with the UV, the spiropyrane is photo-isomerized to photomerocyane and, thereafter, when subsequently heated at 35.degree. to 40.degree. C. for 15 minutes, a J-aggregate of the photomerocyane is formed in very stabilized form. When the recording medium is irradiated with light of wavelength of visible spectrum, the color is bleached with the information consequently recorded. The optical recording medium herein disclosed is rewritable and can retain the recorded information for 5,000 hours or more.

Optical recording medium

A optical recording medium which comprises a substrate and a recording layer of at least two J-aggregates of dyes formed on the substrate is described. The dyes may be photochromic dyes or other types of dyes capable of forming the aggregates which have narrower absorption spectral ranges than original dyes. A plurality of information bits can be written in the recording layer by irradiation of one laser beam spot. The recording layer is formed by an LB film method or a method capable of fluidizing a dye solution in a direction horizontal to the substrate surface. A recording method using the medium is also described.

Optical high density recording mediums, method for making same and

This invention provides an optical filter comprises of a pair of solid polymer films, wherein (1) a first solid polymer film has a planar alignment of a cholesteric liquid crystal structure of either clockwise or counterclockwise helical structure, which alignment allows the light of a specified wavelength to be scattered selectively, and (2) a second solid polymer film has a planar alignment of a cholesteric liquid crystal structure of a helical structure whose helical direction is the opposite to that of the first solid polymer film, which alignment allows the light at the specified wavelength to be scattered selectively, wherein the optical axes of the first and second solid polymer films are made substantially parallel to each other. This invention also provides preparation methods of an optical filter mentioned above.

Optical filter and the method of preparing the same

An optical recording medium comprising a substrate and an information recording layer which consists of monolayer assemblies comprising a photochromic compound of which is based on cis-trans isomerization such as an amphipathic derivative of azobenzene, indigo or thioindigo having a long chain substituent, which monolayers are formed on the substrate by the Langmuir-Blodgett method and oriented in a two-dimensional plain. When the recording medium is irradiated by light, light absorption spectrum of the recording layer changes so that information is recorded. Since the photochromic compound is oriented in a monolayer, its photochromism lasts long.

Optical recording medium and production of the same

A method of manufacturing capacitance video discs comprising thermoplastic resins and conductive carbon black, wherein said conductive carbon black having an average primary particle size of 25 millimicrons or less is washed by water or an inorganic acid, heated at temperatures of 400.degree. to 1,200.degree. C. in a non-oxidizing atmosphere and wherein the coarse particles having a grain size of 0.05 mm or more are substantially eliminated. This method can provide video discs having reduced surface defects and stability after a moisture-proof test.

Method of manufacturing video disc

A pickup cartridge for phonographic records, in which the damper material supporting an end portion of a cantilever is made of an elastomer comprising a blend polymer of a silicone rubber polymer and polyisobutylene. This damper material is advantageous for its high dampability and small temperature dependence of the dampability.

Pickup cartridge

There is provided a hygroscopic resin comprising a vinyl polymer having an epoxy group, said vinyl polymer being a copolymerization product between a vinyl monomer having a hydrophilic property and a further vinyl monomer having an epoxy group. This hygroscopic resin is not soluble in water or organic solvent and is thus useful for various applications, e.g., a humidity sensor can be made by dispersing a conductive powder in the hygroscopic resin. This humidity sensor has high sensitivity to humidity and can operate stably for a long time.

Hygroscopic resin and humidity sensor using the same

An electro-optical device using a liquid crystal consisting of 99.9 to 30 wt.% of at least one nematic liquid crystal and 0.1 to 70 wt. % of at least one optically active liquid crystal compound, (+)-p-alkoxy-p'-(2-methylbutyl)azoxybenzene. Such a device has a better display performance than similar devices because the mixture has a threshold voltage and a rapid response to an electric signal applied to the device, and so it is very practical for a matrix display device.

Electro-optical device

The present invention provides an improved electro-optical device having a cell for containing a liquid crystal and consisting of two light-transparent plates opposed to each other and having electrically conductive electrodes on the inner surfaces thereof, the electrodes on at least one inner surface being transparent and spacer means between said opposed electrodes; and a power supply coupled to said electrodes for applying an electric voltage to said electrodes, whereas the improvement comprises a liquid crystal in said cell between said electrodes consisting of 99.95 to 65 wt.% of at least one nematic liquid crystal and 0.05 to 35 wt.% of at least one optically active compound of the formula: ##EQU1## wherein X is --N=N-- or ##EQU2##

Electro-optic device

The present invention provides an improved electrooptical device having a cell for containing a liquid crystal and consisting of two light-transparent plates opposed to each other and having electrically conductive electrodes on the inner surfaces thereof, the electrodes on at least one inner surface being transparent, and spacer means between said opposed electrodes; and a power supply coupled to said electrodes for applying an electric voltage to said electrodes, whereas the improvement comprises a liquid crystal in said cell between said electrodes consisting of 99.95 to 65 wt.% of at least one nematic liquid crystal and 0.05 to 35 wt.% of at least one optically active compound of the formula; ##SPC1## Wherein X is CH=N, --N=N--or ##EQU1##

A photosensitive composition for electrophotography comprising a combination of poly-N-vinylcarbazole or halogenated poly-N-vinylcarbazole and prepolymer of diallylphthalate. This composition has an improved photodecay characteristics due to the use of the prepolymer of diallylphthalate, gives a high electrostatic contrast of a latent image and is useful for a contact exposure reproduction process.

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Settsu, Japan

Kazuhisa Morimoto