Optical head device and optical information reproducing device

Optical head device and optical information reproducing device

  • CN 1,532,827 A
  • Filed: 03/19/2004
  • Published: 09/29/2004
  • Est. Priority Date: 03/20/2003
  • Status: Active Application
First Claim
Patent Images

1. , optical head device comprises:

  • A light source;

    A collector lens, be used for from the optical convergence of light emitted to being included in optical data recording medium as an Information Level a plurality of Information Levels of target;

    An optical element is used for the light and the optical convergence that (b) reflects from the neighbor information layer from the target information layer reflection with (a), and wherein on optical axis direction, the position of this neighbor information layer and target information layer differs from one another;

    A light receiving element is used to survey each Shu Guang by optical elements focused, and obtains detectable signal;

    WithAn arithmetical circuit utilizes detectable signal to obtain reproducing signal,Wherein, this light receiving element comprises;

    one first light receiving part is used for surveying first detectable signal from the reflection of light light that comprises the target information layer reflection;

    One second light receiving part is used for surveying second detectable signal from the reflection of light light that comprises the reflection of the first neighbor information layer, and in the neighbor information layer, this first neighbor information layer is positioned at than the distance farther position of target information layer to object lens;

    With one the 3rd light receiving part, from the reflection of light light that comprises the reflection of the second neighbor information layer, survey the 3rd detectable signal, in the neighbor information layer, this second neighbor information layer is positioned at the side than the more close object lens of target information layer, andThis arithmetical circuit is with the second detectable signal multiplication by constants K, with the 3rd detectable signal multiplication by constants L, and carry out calculus of differences from first detectable signal, to deduct second detectable signal that multiply by K and the 3rd detectable signal that multiply by L, this constant K is according to the spacing of the target information layer and the first neighbor information layer and definite, and this constant L is according to the spacing of the target information layer and the second neighbor information layer and definite.

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