Taiyo Yuden Co., Ltd.

Takeshi Otsu

Fumi Hara

Isao Matsuda

Motomitsu Hagiwara

Masashi Satoh

Shingo Katoh

Akimasa Miyata

Takuo Kodaira

Shingo Kato

Yuji Tomizawa

Atsuo Shimizu

Shinichi Kojo

An optical information recording medium has at least an optical reflective layer, an optical recording layer, an protective layer, and an optical transparency layer formed in that order on the main surface of a disc-shaped substrate. An area in which the protective layer is formed is made wider than an area in which the reflective layer is formed, and made narrower than an area in which the optical transparency layer is formed.

Optical information recording medium and manufacturing method thereof

An optical information recording medium has a substrate, and an optical reflection layer, an optical recording layer containing an organic dye, an interlayer, and a cover layer formed in this order on the substrate. The interlayer contains a sputtered NbO&#x2014;AlO-based composite oxide having an NbOcontent of more than 50 mol % and less than 60 mol %.

Optical information recording medium

An optical information recording medium includes an optical disk body including a light-transmitting substrate, a recording layer provided on a main surface of the light-transmitting substrate over a region in which pre-grooves are formed and a portion of a region in which dummy grooves are formed, and a reflecting layer provided over the recording layer and a region of the light-transmitting substrate in which the recording layer is not provided; and an ink receiving layer provided on the label surface side of the optical disc body. The dummy grooves provided in at least a portion of the region in which the dye material is not applied have a pitch larger than that of the pre-grooves, are shallower than that of the pre-grooves, or have half-width less than that of the pre-grooves.

An optical information recording medium includes a substrate having a through-hole provided at the central portion thereof and a guiding groove provided on a surface at the light-incident side; a reflective layer provided on the surface of the substrate having the guiding groove; a recording layer provided on the reflective layer and made of an organic substance containing a dye; and a light-transmissive cover layer provided on the recording layer, wherein the cover layer is made of a curable resin, and a modulus of elasticity of at least a portion of the cover layer facing the recording layer is in the range of about 34 MPa to about 96 MPa at 25&#xb0; C.

In a write-once optical information recording medium including a substrate, a groove-shaped track such as a guiding groove, and an optical recording layer containing an organic dye material and disposed on the guiding groove, wherein information is recorded by irradiating a short-wavelength laser beam from a surface of the optical recording layer opposite the substrate, and the information can be reproduced by reading a change in the reflected light of a short-wavelength laser beam after the information recording, an unrecorded portion of the optical recording layer has a lower reflectance than a pit portion formed after recording to a portion of the optical recording layer, the optical recording layer has a refractive index n in the range of about 1.2 to about 2.1 before recording and an extinction coefficient k in the range of about 0.01 to about 0.7 before recording, and n+k is in the range of about 1.4 to about 2.1.

Optical informaton recording medium

An optical information recording medium is provided having a superior jitter property even when an organic substance is used for a recording layer. The optical information recording medium has a substrate having a penetrating hole in a central portion thereof and a spiral pre-groove provided in one surface of the substrate, a reflection layer provided on the surface of the substrate in which the pre-groove is provided, a recording layer which is provided on the reflection layer and which is composed of an organic substance including a dye, and a light transmissive cover layer provided on the recording layer. In the optical information recording medium, the cover layer has an elastic modulus of 40 MPa or less at 25&#xb0; C. in an interface region facing the recording layer.

An optical information recording medium includes a disk-like substrate having a hole in a central portion thereof, and a light-reflective layer, a dye recording layer containing an organic dye, an intermediate layer composed of an inorganic substance, and a light-transmissive layer composed of a resin disposed in that order on one principal surface of the substrate, in which information is recorded/reproduced by irradiation of laser light from the light-transmissive layer side. In the optical information recording medium, the light-transmissive layer covers a surface of the intermediate layer from an inner peripheral edge of the intermediate layer to an outer peripheral edge of the intermediate layer, and a vicinity of an outer peripheral edge of the light-transmissive layer is in contact with the substrate in an annular region extending around an outer peripheral side of the substrate.

An optical information recording medium having a disk-shaped substrate formed with spiral grooves on one main surface, and having an optical reflection layer formed with grooves at the surface corresponding to the grooves of the substrate for reflecting a laser beam, an optical recording layer, a protective layer, and an optical transparency layer in this order on the main surface thereof. The optical information recording medium has a main information area and a sub-information area to the inner circumferential side thereof, in which the track pitch TrB of the grooves in the sub-information area is about 0.32 &#x3bc;m or less, and the depth D of the grooves and the half-band width W of the grooves satisfy a relation represented by: W&#x2267;2D+70, whereby the difference between the reflectivity at the land surface and the reflectivity at the groove surface in the sub-information area can be restricted to less than 30%, thereby preventing occurrence of mis-decipherment for BCA marks.

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Gunma, Japan

Takeshi Otsu