Mitsui Toatsu Chemicals, Incorporated

Masatoshi Yanagimachi

Sumio Hirose

Hideki Umehara

Yoshiteru Taniguchi

Keisuke Takuma

Tsutami Misawa

Shin Aihara

Provided is an optical recording medium in which per-pits in a ROM area have a depth of 250 nm or more and 350 nm or less; pre-grooves between the pre-pits have a depth of 30 nm or more and 170 nm or less; wobbling tracks have an amplitude of 25 nm or more and 110 nm or less; the product of the depth of the pre-grooves between the pits and the wobble amplitude of the track is 3100 or more; and pre-grooves in a RAM area have a depth of 130 nm or more and 250 nm or less. The optical recording medium is a hybrid disk having such good signal characteristics as satisfying the Orange Book standards.

Optical recording media

An optical recording medium has a recording layer, a reflective layer and a protective layer, all of which are arranged on a substrate. The recording layer contains a porphyrin compound represented by the following formula (1): ##STR1## wherein R.sub.1 to R.sub.8 independently represent a hydrogen atom, an alkyl group, an alkoxy group, an alkylcarbonyl group, an alkoxycarbonyl group, an alkylthio group or a halogen atom, R.sub.9 to R.sub.12 independently represent a hydrogen atom or an alkyl group, and X.sup.- represents an anion.

There is provided with an optical recording medium comprising at least a dye-containing recording layer and a reflective layer laminated on a transparent substrate in this order which has a reflectance of 65% or higher, measured through the substrate, to a light beam having a selected wavelength (.lambda.1) of from 770 to 830 nm and has a reflectance of 15% or higher to a light beam having a selected wavelength (.lambda.2) of from 630 to 690 nm and which is recordable and reproducible with a laser beam having the wavelength of .lambda.1 and being reproducible with a laser beam having the wavelength of .lambda.2. In addition, the recording layer has a dye A having the absorption maximum at the wavelength shorter than 630 nm mixed with a dye B having the absorption maximum at the wavelength of from 630 to 900 nm. Alternatively, an interference layer is provided along with the recording and reflective layers. The recording layer is based on a phthalocyanine dye while the interference layer is based on an inorganic dielectric, a polymer, or an azo dye. The requirements for the interference layer are also provided.

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Funabashi, Japan

Masatoshi Yanagimachi