High density optical disc configuration

An optical disc includes two transparent substrate layers each having a recording surface with a plurality of pits arranged concentrically or spirally. The plurality of pits represents information stored on the recording surface. Each transparent substrate layer has a thickness of 0.6+/-0.03 mm. A r...

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Bibliographic Details
Main Authors SUGAWARA; YUKIHIRO, FUKUOKA; SATORU
Format Patent
LanguageEnglish
Published 16.03.1999
Edition6
Subjects
INFORMATION STORAGE
INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORDCARRIER AND TRANSDUCER
PHYSICS
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Summary:An optical disc includes two transparent substrate layers each having a recording surface with a plurality of pits arranged concentrically or spirally. The plurality of pits represents information stored on the recording surface. Each transparent substrate layer has a thickness of 0.6+/-0.03 mm. A reflecting layer is formed on each of the recording surfaces of the two transparent substrate layers. An inclining angle formed between a pit inner wall and a normal line of each transparent substrate layer is 20 DEG -55 DEG , and pit depth is set to be lambda /3.5N- lambda /2.7N. lambda is defined as the wavelength of a laser beam incident the optical disc for reading the information recorded on the optical disc, and N is the index of refraction of each transparent substrate layer.
Bibliography:Application Number: US19970858501