Tdk Corporation

Yoshimi Sakai

Kenji Yamaga

Mamoru Usami

Junichi Satou

Hisaji Oyake

Atsushi Koyama

Yuuichi Kawaguchi

Hiroaki Takahata

Yuichi Namikawa

Seiki Shimazu

Tomoki Ushida

Akira Itoga

Yoshiki Satoh

A disc-shaped optical recording medium formed by carrying out a film formation process on a disc-shaped substrate material and completed by forming a center hole at the last step is manufactured in a manner such that no eccentricity will occur when the recording medium is loaded onto a drive. At the last step of an optical disc manufacturing process, i.e., at the time of opening a hole in the center partof the disc-shaped substrate materialformed with at least a resin layer on one side thereof, the center partis removed in a manner such that the diameter of the chucking center holeis larger on the disc-shaped substrate materialside than on the light transmitting resin layerside of the disc-shaped optical recording medium, thereby manufacturing the disc-shaped optical recording medium

Method for manufacturing discoid optical record medium and discoid optical record medium

A method for manufacturing an optical recording medium of the present invention includes the steps of forming an underlying layer having a brightness of 8 or more and a chroma of 4 or less on a label surface of a disk body by a spin coating process, and forming an ink-receiving layer on the underlying layer. In the present invention, the underlying layer having a brightness of 8 or more and a chroma of 4 or less is formed by a spin coating process, thereby significantly decreasing the surface roughness of the underlying layer. Even if the ink-receiving layer is formed by the spin coating or slit coating process in which the surface quality of the underlying layer is greatly reflected, therefore, the average surface roughness (Ra) of the ink-receiving layer can be significantly decreased. Thus, printing by an ink jet printer can produce a color and brilliance close to those of a silver salt photograph.

Optical recording medium and method for manufacturing the same

An optical recording medium of the present invention includes a disk body and an ink-receiving layer disposed on a label surface of the disk body, wherein the ink-receiving layer has a brightness ofor more, a chroma of 4 or less, and an average surface roughness (Ra) of 0.1 &#x3bc;m or less. Therefore, a colored layer of white ink need not be provided below the ink-receiving layer to simplify the manufacturing process. Furthermore, even when the ink-receiving layer is formed by a spin coating or slit coating process in which the surface quality of an underlying layer is greatly reflected, therefore, the average surface roughness (Ra) of the ink-receiving layer can be significantly decreased. Thus, printing by an ink jet printer can produce a color and brilliance close to those of a silver salt photograph.

Optical recording medium

An optical recording medium is made by a step of bonding a light-transmissive substrate to a supporting substrate having a brightness of 8 or more and a saturation of 4 or less via a bonding layer composed of an epoxy resin; and a step of forming a transparent ink-receiving layer on a surface of the supporting substrate remote from the light-transmissive substrate. The bonding using the epoxy resin is conducted by a method of curing the resin by using a cationic initiator, a method of curing the resin by an addition reaction between the resin and a crosslinking agent containing an active hydrogen compound, a method of curing the resin by heating, or the like. In this invention, the bonding layer is composed of a material containing an epoxy resin instead of a radically polymerizable UV-curable resin typically used. Thus, although UV irradiation through the supporting substrate is not possible, the light-transmissive substrate can be securely bonded to the supporting substrate.

Optical recording medium and method for making the same

A stamper for forming a data recording region on a recording medium substrate by means of a transfer surface thereof. The transfer surface transfers a predetermined set of data to the recording medium substrate. The stamper is fitted on at least one of metal molds that are arranged opposite one another for forming the recording medium substrate. The stamper includes a stepped portion formed as bends in the material of the stamper. The stepped portion is configured to project from the transfer surface toward the recording medium substrate.

Stamper, mold system, recording medium substrate, recording medium, optical disc substrate, optical disc, and method for producing stamper

A method of making a plurality of optical record disc substrates includes the steps of injecting a resin material into a plurality of disc-shaped cavities which are formed by closing a fixed mold half and a movable mold half; and cooling the injected resin material in the cavities. The cavities are grouped into a plurality of groups so that each group includes not less than one cavity, and each group is provided with a common actuation device so that each actuation device is independently operated.

Apparatus for making a plurality of optical record disc subtrates

Method of making a plurality of optical record disc substrates

A guard panel for tape cassettes and methods and apparatus for manufacturing the same wherein the guard panel comprises an upper plate portion which is devoid of cracks and deformation. The guard panel, which is adapted to be pivotally mounted on the cassette housing, comprises an elongated plate member including front, upper and side plate portions, each forming a side wall of the plate member. The upper plate portion includes at least two sections which differ in thickness from another section, the two sections being spaced from each other by a central section of the upper plate portion which is interposed between them in the longitudinal direction. The sections of the upper plate portion which differ in thickness from the other section may be in the form of recesses or protrusions formed in the upper plate portion and preferably on the back surface thereof. An additional recess or protrusion may be formed in the central section of the back surface of the upper plate portion. The guard panel is manufactured in a mold having a cavity block and a core block, the latter having a molding surface on which is provided at least two protrusions or recesses which are spaced from each other by a central portion of the molding surface interposed between them in the longitudinal direction. When molten plastic material is injected into the mold, the recesses or protrusions corresponding to the protrusions or recesses provided in the core block are formed on the back surface of the upper plate portion.

Growing community of inventors

Tokyo, Japan

Yoshimi Sakai