Matsushita Electric Industrial Co., Ltd.

Masami Uchida

Takeo Ohta

Kazumi Yoshioka

Shigeaki Furukawa

Katsumi Kawahara

Takao Inoue

Yukio Maeda

Kazuo Inoue

Koichi Kotera

Seiko Minamide

Keiichiro Horai

Kunihiro Matsubara

A reflecting film for use in an optical recording medium, which essentially consists of gold. The reflecting film also is capable of including a second reflecting layer essentially made of aluminum. An optical recording medium includes a recording film, the reflecting layer(s), an adhesive layer, and a cover layer for covering a surface of the adhesive layer, which are formed on one surface of a transparent substrate in this order.

Optical recording medium and reflecting film for use therein

An optical information recording medium is disclosed in which the recording layer is a material capable of absorbing energy and being reversibly converted between a substantially non-crystalline or amorphous state and a substantially crystalline state. The recording layer is a Te-Ge-Sb composition which also contains nitrogen. The optical recording medium includes a substrate onto which is sequentially deposited a first dielectric layer, a nitrogen-containing recording layer, a second dielectric layer and a metallic reflecting layer. In order to control the sensitivity of the medium to laser irradiation, the second dielectric layer is graded in thickness and progressively becomes thicker as a function of increasing radius. Alternatively, in another embodiment, the reflecting layer is graded in thickness, and progressively becomes thinner as a function of increasing radius. To further optimize the write/erase characteristics, the write to erase power ratio, as well as the recording duty cycle of the laser are varied as a function of radial position.

Method of recording and erasing information in an erasible optical

An optical information recording medium is provided in which the active layer is a phase change material capable of absorbing energy and being converted between a substantially amorphous state and a substantially crystalline state. The active layer contains nitrogen, which may be in the form of a nitride or nitrides of the constituent elements of the active layer, or may be a nitrided surface thereof. The inclusion of nitrogen inhibits localized shifting of the active material, which leads to degradation of the recording/erase properties of the medium. The optical recording medium includes a substrate, onto which is deposited in sequence a first dielectric layer, a nitrogen-containing active layer, a second dielectric layer, and a metallic reflecting layer. The second dielectric layer is made thin, so that the cooling rate of the active layer is increased to form a more uniform amorphous state.

Optical recording medium and production process for the medium

Disclosed is an optical information recording medium which comprises an active layer which undergoes phase change upon irradiation with light and protective layers formed on both the sides of the active layer, wherein the thermal capacity of the active layer which is a heat source is decreased, a reflection layer of high thermal conductivity is provided on the protective layer to cause increase of the coefficient of lines expansion of the protective layer with increase in distance from the active layer or the thickness of each layer is specified to make nearly the constant maximum temperature by irradiated light against a change in the thickness of the active layer.

Optical information recording medium

A method of depositing the layers of an optical recording medium to their requisite thicknesses is disclosed in which optical monitoring of the reflectivity of a first dielectric layer during deposition is used to determine the deposition rate. The reflectivity is monitored to determine the time period in which the reflectivity reaches a maximum or minimum value, which occurs when the layer is a quarter wave thick. The deposition rate is derived from that time period, and the deposition is continued for a time in accordance with the deposition rate until the requisite thickness of the first dielectric layer is obtained. The second dielectric layer is deposited for a lesser time period in accordance with the deposition rate which has been optically derived during deposition of the first dielectric layer.

Process for manufacturing an optical recording medium

Bonding of a protection sheet on the substrate of the information storing disk is made by revolving the substrate and the protection film with viscous adhesive applied therebetween, to spread it by centrifugal force, and, after slowing down the rotation speed, UV light is irradiated through the protection film to harden the adhesive.

Method for producing information storage disk

Method of manufacturing an optical recording/reproducing disc

A manufacturing method for an optical type recording and reproducing disc and the like, comprising the steps of, applying a coating liquid to opposite planar surfaces of the disc except for the central portions by rotating the disc, with the opposite planar surfaces of the disc being simultaneously dipped in the coating liquid, and thereafter, simultaneously curing the coating liquid applied to the opposite planar surfaces of the disc while rotating the disc.

Growing community of inventors

Osaka, Japan

Masami Uchida