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Optical disc apparatus

A kind of equipment and optical disc technology, which is applied in the direction of optical recording head, light beam guiding device, optical recording/reproduction, etc., can solve the problems of increasing the cost of the signal reproduction system, increasing the noise level, etc.

Inactive Publication Date: 2006-01-25
KK TOSHIBA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

This increases the cost of the signal reproduction system and increases the noise level

Method used

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  • Optical disc apparatus
  • Optical disc apparatus
  • Optical disc apparatus

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Embodiment Construction

[0021] Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0022] figure 1 is a schematic diagram of an optical disc suitable for recording and reproducing information by the optical head unit of the present invention which will be described later with reference to FIG. 2 .

[0023] Such as figure 1 As shown in , an optical disc (recording medium) 1 has a first information recording layer 3 including a phase change recording film on a first substrate 2 made of polycarbonate.

[0024] On the first information recording layer 3 , a spacer layer 4 having a predetermined transmittance with respect to the wavelength of the laser beam emitted from the semiconductor laser unit 20 of the optical head unit 11 is stacked. On the spacer layer 4, a second information recording layer 5 is stacked. The spacer layer 4 is usually made of adhesive or ultraviolet curable resin. The second information recording layer...

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Abstract

The present invention provides an optical disc apparatus (11) of the invention, by locating, at a position displaced a predetermined distance from the focal point of a condenser lens (25), a light-receiving surface of a photodetector (26) for receiving a laser beam reflected from first and second recording layers of an optical disc, is configured, when playing back a signal from a certain recording layer, to decrease the difference in a crosstalk caused by a light reflected from other recording layers.

Description

technical field [0001] The present invention relates to an optical disc apparatus capable of simplifying a signal reproduction system with little crosstalk when reproducing information from an optical disc having information recorded in two or more recording layers. Background technique [0002] Optical discs used as information recording media may be play-only type typified by CD and DVD-ROM, write-once type typified by CD-R and DVD-R, and external memory for computers and record-reproduce video ( Rewritable type for video recording). [0003] Currently, in order to increase the recording capacity of existing standard DVDs, studies are underway to increase the number of recording layers to two or more. For this reason, it is necessary to make the spacer layer between the recording layers thinner than that in the existing standard DVD. However, it is well known that crosstalk between layers increases when the spacer layer is thinner. [0004] In addition, it is well known...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G11B7/12G11B7/135G11B7/00G11B7/1353G11B7/1372G11B7/1381
CPCG11B7/1353G11B7/1381G11B2007/0013G11B7/1372G11B7/0935G11B7/08G11B7/135
Inventor 丸山纯孝小川昭人岩田胜雄渡部一雄
Owner KK TOSHIBA