Tdk Corporation

Atsuko Motai

Hideki Hirata

Hiroyuki Arioka

Toshiki Aoi

Toshifumi Tanaka

Setsuko Shibuya

Junji Tominaga

Akio Ogawa

Mamoru Usami

Kenji Uchiyama

Koji Yasukawa

In an optical recording medium comprising an organic dye base recording layer and a reflective layer on a resin substrate having a groove of 1,100 to 2,300 .ANG. deep formed in one surface thereof, signals are written by directing recording light to the recording layer within the groove from the back side of the substrate at a relative linear velocity of at least 3.6 m/s whereby record marks are formed in the recording layer as a result of partial decomposition of the dye while deforming the groove bottom surface. The deformation of the groove bottom surface is minimized to less than 18% of the groove depth. The medium requires a short time for recording and offers reduced jitter on reproduction.

Optical recording/reproducing method

An optical recording disk includes on a substrate 2, a dye recording layer 3, a lower reflective lamina 4, an upper reflective lamina 5, and a protective coat 6. The lower reflective lamina 4 is formed of Au, Pt, Ag, Al or an alloy thereof and the upper reflective lamina 5 is of a stainless steel composition or an alloy containing 30 wt % or more of Cu and at least one element selected from the group consisting of Zn, Ti, V, Ta, Cr, Mo, W, Mn, Fe, Co, Rh, Ni, Pd, Pt, Ag, Au, Al, Sn, Si, Pb, Cd, Hg, Ca, In, As, Sb, Bi, Se, Te, Ge, N and O. The disk is well reliable and less costly.

Optical recording disk

In an optical recording disk comprising a substrate, a dye base recording layer, and a reflective layer, the recording layer contains a metal complex having a center metal, and the reflective layer is formed of an alloy of at least two metal elements wherein the total content of a metal element(s) having ionization tendency equal to or greater than the center metal is limited to 0 to 10% by weight. This minimizes reaction between metals in the recording and reflective layers, maintaining the disk reliable.

Otical record disk

An optical recording disk includes a resin substrate having a recording layer thereon and a protective glass substrate, which are joined into an integral disk such that the recording layer is inside. The resin substrate is formed of a resin composition comprising a specific cyclic polyolefin and an optional alkyl phenol condensate. The resulting lightweight, rigid disk is adapted for recording/reproducing operation at high rotational speeds with few focusing errors due to minimized axial runouts.

An optical recording disk is constructed using a substrate which is injection molded from a mixture of a cyclic polyolefin and up to 2% by weight of an alkyl phenol condensate. A recording layer remains firmly adhered to the substrate even in a hot humid environment.

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Saku, Japan

Atsuko Motai