Nippon Telegraph and Telephone Public Corporation

Shigeru Oikawa

Norio Takato

Takashi Kurokawa

Yuzo Katayama

Hirotsugu Sato

Toshikuni Kaino

Akira Morinaka

Shigeo Nara

Michiya Fujiki

Optical recording medium includes a substrate, a coloring agent layer formed on the substrate, a light absorber layer formed on the coloring agent layer and a developer layer formed on the light absorber layer. The coloring agent layer is separated from the developer layer by the light absorber layer and the lamination layer composed of these layers has a uniform thickness. The optical recording medium is produced by vacuum depositing a coloring agent, a light absorber and a developer successively on the substrate to form a multi-layer construction, the substrate being capable of transmitting visible light and near infrared light. Alternatively, the optical recording medium contains a plurality of lamination layers mentioned above. The optical recording medium has a high contrast and achieves a high speed multi-color recording.

Optical recording media with thermal coloration and process for

In a sealed system, a polymerization initiator and a chain transfer agent are added to a methyl methacrylate monomer distilled under reduced pressure condition via a distillation step of the former both ingredients, the methyl methacrylate monomer is successively polymerized to prepare a core polymer while maintaining the reduced pressure condition, then the resulting core polymer is subjected to melt spinning to form a core fiber while maintaining the sealed system, and a clad of a macromolecular compound having a refractive index lower than that of the aforesaid core fiber is adhered around the periphery thereof, whereby a low-loss plastic optical fiber with excellent optical transmission characteristics having a core-cladding structure is fabricated. Plastic optical fibers so made exhibit light attenuation as low as 60 dB/km or lower.

Fabrication of a low-loss plastic optical fiber

Coordinate input apparatus

A polymer optical circuit with optical lead-fibers which comprise a plurality of optical fibers, each one end portion thereof being embedded in a transparent polymer film formed on a substrate, and polymer optical waveguides formed in the film between the embedded ends of the optical fibers so that the terminal ends of the optical waveguides are connected with the embedded ends of the optical fibers; the substrate, polymer film, polymer optical waveguide and optical fibers being formed as an integrated unit. A process for fabricating this polymer optical circuit is also disclosed.

Polymer optical circuit with optical lead-fibers and method of

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Mito, Japan

Shigeru Oikawa