Tdk Corporation

Hideki Ishizaki

Suguru Takayama

Kenji Uchiyama

Hajime Utsunomiya

Hiroyuki Arioka

Hiroshi Takasaki

Hideki Hirata

Masaharu Nishimatsu

Toshiaki Ide

Hiroyasu Inoue

Mamoru Usami

Masanori Kosuda

Masanori Shibahara

Takayoshi Kobuke

Yoshihisa Tamagawa

Tsutomu Tsutsumi

Osamu Hasegawa

An optical recording medium includes a support substrate, a light transmission layer whose one surface constitutes a light incidence plane through which a laser beam is projected, an information recording layer formed between the support substrate and the light transmission layer, a reflective layer formed between the information recording layer and the support substrate, a water proof layer formed between the reflective layer and the support substrate and containing a mixture of ZnS and SiOas a primary component, and a corrosion resistant layer formed between the water proof layer and the reflective layer. According to the thus constituted optical recording medium, it is possible to effectively prevent a reflective layer from being corroded and has excellent storage reliability.

Optical recording medium

The optical recording medium of the invention comprises a recording layer and at least one mixed dielectric layer. The mixed dielectric layer contains cerium oxide and an additive compound. The additive compound is at least one compound selected from among aluminum oxide, chromium oxide, iron oxide, manganese oxide, niobium oxide, magnesium oxide, zinc oxide, titanium oxide, yttrium oxide, tantalum oxide, antimony oxide, zirconium oxide, bismuth oxide and magnesium fluoride. The optical recording medium has a high storage reliability and satisfactory recording/reading characteristics.

A vacuum processing apparatusis provided with a bypass linefor causing a vacuum transfer chamberand a load-lock chamberto communicate with each other, and a bypass opening and shutting valvefor opening and shutting the corresponding bypass line, wherein by opening the bypass opening and shutting valve, a pressure-reduced state at the vacuum transfer chamberside can be shifted to the load-lock chamberside, and the pressure reduction of the load-lock chambercan be carried out in a short time.

Vacuum processing apparatus and method for producing an object to be processed

A disc-shaped substrate for a disc-shaped optical recording medium is accurately and stably positioned and held during a sputtering process. A non-sputtering surface of the disc-shaped substrate opposite to a sputtering surface has a circular recess formed at a center thereof. A carrier, on which the disc-shaped substrate is supported during the sputtering process, has a projective member for fitting into the circular recess to accurately position and hold the disc-shaped substrate during the sputtering process.

Method for manufacturing disc-shaped optical recording medium and disc-shaped substrate for optical recording medium

An optical recording medium comprising a recording layer on a substrate and an intermediate layer between the substrate and the recording layer exhibits high reflectance and corrosion resistance when the intermediate layer comprises silicon, aluminum, oxygen, nitrogen, and at least one element selected from the group consisting of yttrium, lanthanide elements and actinide elements, and contains 0.1 to 2 atom % of the element and 20 to 90 atom % of silicon and nitrogen combined or 2 to 35 atom % of the element and 20 to 95 atom % of silicon and nitrogen combined.

An optical recording medium comprising a recording layer on a substrate and a protective layer formed adjacent to the upper or lower surface of the recording layer is more durable and corrosion resistant when the protective layer has a composition comprising silicon, a divalent metal such as Ba, Ca or Sr, oxygen, and nitrogen. An intermediate layer containing silicon, a metal or metalloid such as aluminum or lanthanum, oxygen and nitrogen is formed between the protective layer and the recording layer.

An optical recording medium comprising a recording layer on a substrate is more durable when an intermediate layer of a composition comprising a rare earth element oxide, silicon oxide, and silicon nitride is formed between the substrate and the recording layer.

An optical recording medium comprising a recording layer on a substrate and a protective layer formed adjacent to the upper and/or lower surface of the recording layer is more durable and corrosion resistant when the protective layer has a composition comprising, in % by weight, 40-60% of SiO.sub.2, 0.5-10% of an alkali metal oxide, 10-59.5% of Al.sub.2 O.sub.3 and/or B.sub.2 O.sub.3, and optionally up to 50% of a divalent metal oxide.

In an optical recording medium comprising a substrate and a recording layer thin film comprised of a rare earth element and a transition metal, for example, TbFeCo on the substrate, a metal thin film layer having a high magnetic permeability, for example, Permalloy is formed on the recording layer. A transparent dielectric film layer may be formed between the substrate and the recording layer thin film.

Optical magnetic recording medium

Magnetic recording tape comprising a ferromagnetic thin film on a non-magnetic base and having good running stability and low output fluctuation, clogging, and dropout can be obtained by making the stiffness of the overall tape

Magnetic recording medium for image recording

A magnetic recording medium comprising a non-magnetic substrate, a ferromagnetic thin film formed on the substrate, and a top coating layer containing a fine particulate pigment, formed on the surface of the ferromagnetic thin film, wherein the top coating layer satisfies the condition of 0.3x&lt;y&lt;2x where x is the average particle size of the fine particulate pigment and y is the thickness of the top coating layer, and the average particle size x is less than 200 .ANG..

Magnetic recording medium

A magnetic recording medium comprising a non-magnetic substrate, a magnetic recording layer formed on the substrate, and a top coating layer formed on the magnetic recording layer, wherein the top coating layer contains a fine particulate pigment at its surface, and the surface roughness (R20) of the top coating layer is less than 400 .ANG..

A magnetic recording medium comprising a magnetic recording layer formed on one major surface of a non-magnetic substrate and a topcoat layer formed on the magnetic layer is characterized in that the topcoat layer contains a submicron particulate pigment observable under an electron microscope to have a linear distribution density of 10 to 1,000 per linear 100 .mu.m and a particle size of less than 200 .ANG. whereby the topcoat layer has a surface roughness R20 of not more than 400 .ANG..

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Tokyo, Japan

Hideki Ishizaki