Taiyo Yuden Co., Ltd.

Taiyo Yudenco., Ltd.

Fumi Hara

Isao Matsuda

Takeshi Otsu

Masashi Satoh

Toru Fujii

Motomitsu Hagiwara

Shingo Katoh

Yuji Arai

Takuo Kodaira

Akimasa Miyata

Sachiko Ishibashi

Shingo Kato

Atsuo Shimizu

Yoshikazu Takagishi

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 comprises at least a substrate on which a groove is formed in a recording area, a recording layer comprising an organic dye, and a reflective layer. The recording area has a preformat area and a data area, and the groove in the preformat area is narrower or shallower than that in the data area.

Optical information recording medium and mold apparatus for manufacturing the same

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.

For improving the humidity resistance reliability and the jitter property of an optical disk, the adhesive layer used for bonding a bonding type optical information recording medium is defined such that the glass transition temperature is 100&#xb0; C. or higher at 200&#xb0; C. or lower, the modulus of elasticity at 25 to 80&#xb0; C. is 1000 MPa or more, the adhesion strength thereof is 4 N or more, the reflective layer is defined such that the hardness is 60 mgf/&#x3bc;mor more as the nano indentation hardness, and the dye recording layer is defined such that the water solubility of the dye as light absorption is 0.2 or less.

For improving the jitter property and ensuring the high reliability of an optical disk, a metal film containing phosphorus is disposed in a reflective layer. The layer has a hardness of 60 mgf/&#x3bc;mor more as nano indentation hardness, and an adhesive layer used for bonding has a glass transition temperature of 100&#xb0; C. or higher but 200&#xb0; C. or lower, an elastic modulus at 25 to 80&#xb0; C. of 1000 MPa or more, and an adhesion strength of 4N or more. The dye for the dye recording layer has a water solubility of 20% or less as measured as light absorbance of hot water in which the dye recording layer is soaked.

Growing community of inventors

Gunma, Japan

Fumi Hara