JP2010165437A5

JP2010165437A5 -

Info

Publication number: JP2010165437A5
Application number: JP2009008756A
Authority: JP
Filing date: 2009-01-19
Publication date: 2012-01-19
Anticipated expiration: 2029-01-19

Description

本発明の光ヘッド装置は、レーザ光を出射する光源と、光ディスクに前記レーザ光を集光する対物レンズと、前記光ディスクに集光させたレーザ光の反射光を受光する複数の受光素子を有する光検知器と、前記対物レンズと前記光検知器との間に配置され、前記光ディスクの情報記録層のうち、記録再生の対象となる情報記録層からの反射光の回折光を前記複数の受光素子に入射させる回折素子と、を備え、前記回折素子は、前記反射光の光軸に垂直な面内において、前記反射光の回折光を回折させて前記複数の受光素子にそれぞれ入射させる複数の光学領域に分割されており、当該複数の光学領域は、前記光軸上に配置された第１の光学領域と該第１の光学領域以外の第２の光学領域とを含み、前記複数の受光素子は、前記第１の光学領域からの回折光を受光する第１の受光素子と前記第２の光学領域からの回折光を受光する第２の受光素子とを含み、前記第２の受光素子は、前記記録再生の対象となる情報記録層に隣接する情報記録層からの反射光の回折光が入射しないように配置されており、前記第１の光学領域は、前記光ディスクの情報記録層のうち前記記録再生の対象となる情報記録層よりも奥側に隣接する情報記録層からの反射光が集光する位置に形成された回折格子構造を有している。 An optical head device of the present invention includes a light source that emits laser light, an objective lens that condenses the laser light on an optical disc, and a plurality of light receiving elements that receive reflected light of the laser light condensed on the optical disc. A plurality of light-receiving diffracted lights of reflected light from an information recording layer which is disposed between a light detector, the objective lens and the light detector, and is an information recording layer of the optical disc, which is a target for recording and reproduction. comprising a diffraction element to be incident on the element, wherein the diffraction element, in a plane perpendicular to the optical axis of the reflected light, a plurality of which are incident to the plurality of light receiving elements by diffracting the diffracted light of the reflected light is divided into the optical region, the plurality of optical region includes a first optical region and a second optical region other than the first optical regions disposed on the optical axis, the plurality of light receiving The element is the first optical region. And a second light receiving element for receiving a first diffracted light from said light receiving element a second optical regions for receiving et diffracted light, the second light receiving element is subject to the recording The first optical region is arranged so that the diffracted light of the reflected light from the information recording layer adjacent to the information recording layer does not enter , and the first optical region is information to be recorded and reproduced in the information recording layer of the optical disc. It has a diffraction grating structure formed at a position where reflected light from the information recording layer adjacent to the back side of the recording layer is condensed .

Claims

A light source that emits laser light;
An objective lens for condensing the laser beam on an optical disc;
A photodetector having a plurality of light receiving elements for receiving reflected light of the laser beam condensed on the optical disc;
Diffraction that is arranged between the objective lens and the light detector and causes the diffracted light of the reflected light from the information recording layer of the information recording layer of the optical disc to enter the plurality of light receiving elements. Elements,
With
The diffraction element is, in a plane perpendicular to the optical axis of the reflected light is divided into a plurality of optical regions to be incident respectively the said plurality of light receiving elements by diffracting the diffracted light of the reflected light,
The plurality of optical regions include a first optical region disposed on the optical axis and a second optical region other than the first optical region ,
The plurality of light receiving elements include a first light receiving element that receives diffracted light from the first optical region and a second light receiving element that receives diffracted light from the second optical region,
The second light receiving element is disposed so that the diffracted light of the reflected light from the information recording layer adjacent to the information recording layer to be recorded and reproduced does not enter .
The first optical region is a diffraction formed at a position where reflected light from an information recording layer adjacent to the back side of the information recording layer to be recorded / reproduced of the information recording layer of the optical disc is condensed. Has a lattice structure
An optical head device.

The second light receiving element is adjacent to the front side of the information recording layer to be recorded and reproduced among the plurality of information recording layers according to the position of the second optical region with respect to the optical axis. so as not to receive the diffracted light of the reflected light from the recording layer, the optical head apparatus according to claim 1, characterized in that it is arranged and have a size.

The second light receiving element includes a light-receiving element comprising a pair arranged so as to have an axis of symmetry within the light receiving surface of the photodetector to a difference signal of one another,
Receiving element forming the pair, relative to the first light receiving element, in the direction of the front Symbol symmetry axis, in front of the subject to the information recording layer of the recording of the plurality of information recording layers claims, characterized in that <br/> the zero-order light of the reflected light from the adjacent information recording layer is provided is separated a distance corresponding to half the size of the incident region incident on the light receiving plane Item 3. The optical head device according to Item 1 or 2 .

A turntable for mounting an optical disc;
A laser beam is collected and reflected light is detected for recording information on an information recording layer of an optical disc mounted on the turntable and rotating, or for reproducing information recorded on the information recording layer. An optical head device according to any one of 1 to 3 ,
A control unit that controls the optical head device to cause the information recording layer to follow the laser beam based on the reflected light;
An optical disc device comprising: