Hologram reproducing apparatus and hologram reproducing method

Patent metadata

Field	Value
Publication number	US-2016232933-A1
Application number	US-201315022935-A
Country	US
Kind code	A1
Filing date	Sep 18, 2013
Priority date	Sep 18, 2013
Publication date	Aug 11, 2016
Grant date	—

Abstract

The purpose of the present invention is to provide a hologram reproducing apparatus and a hologram reproducing method, which are suitable for reproducing hologram. The purpose can be achieved by means of a hologram reproducing apparatus, which reproduces information signals by irradiating an optical information recording medium with reference light, and a hologram reproducing method for the hologram reproducing apparatus. The hologram reproducing apparatus is characterized in being provided with: a polarization conversion section, which converts polarization of diffracted light that is generated when the optical information recording medium is irradiated with the reference light; a light receiving section, which receives the diffracted light having the polarization thereof converted by means of the polarization conversion section; and a servo signal generating circuit section, which generates signals for moving the optical information recording medium or the polarization conversion section using the diffracted light received by means of the light receiving section.

First claim

1 . A hologram reproducing apparatus which reproduces an information signal by radiating reference light to an optical information recording medium, comprising:
a polarization converting unit that converts polarization of diffracted light generated when the reference light is radiated to the optical information recording medium; a light receiving unit that receives the diffracted light of which the polarization has been converted by the polarization converting unit; and a servo signal generating circuit unit that generates a signal to move the optical information recording medium or the polarization converting unit, using the diffracted light received by the light receiving unit.

2 . The hologram reproducing apparatus according to claim 1 ,
wherein the diffracted light is reproduced light.

3 . The hologram reproducing apparatus according to claim 1 , further comprising:
a polarization branching unit that branches a travelling direction of the diffracted light polarized by the polarization converting unit, wherein the light receiving unit receives the diffracted light branched by the polarization branching unit.

4 . The hologram reproducing apparatus according to claim 1 ,
wherein the polarization converting unit causes the diffracted light passing through the polarization converting unit to be polarized in different directions.

5 . The hologram reproducing apparatus according to claim 4 ,
wherein the polarization converting unit causes polarizations of the diffracted light passing through the polarization converting unit to be substantially orthogonal to each other.

6 . The hologram reproducing apparatus according to claim 1 ,
wherein the polarization converting unit includes a region of a polarization diffraction grating.

7 . The hologram reproducing apparatus according to claim 6 ,
wherein the light receiving unit receives the diffracted light passing through the region of the polarization diffraction grating included in the polarization converting unit.

8 . The hologram reproducing apparatus according to claim 1 ,
wherein the polarization converting unit includes a light shielding region that shields the diffracted light.

9 . A reproducing method of a hologram reproducing apparatus which reproduces an information signal by radiating reference light to a hologram in an optical information recording medium, comprising:
a step of converting polarization of predetermined diffracted light of diffracted light generated from the hologram in the optical information recording medium when the reference light is radiated to the optical information recording medium; a step of receiving the diffracted light of which the polarization has been converted; and a step of generating a signal to move the optical information recording medium or the polarization converting unit, using the received diffracted light.

10 . The reproducing method of the hologram reproducing apparatus according to claim 9 ,
wherein the step of generating the signal to move the optical information recording medium or the polarization converting unit, using the received diffracted light, includes a step of separating signals obtained from the light receiving unit into an X component, a Y component, and a Z component, a step of executing an operation such that the X component, the Y component, and the Z component become predetermined amounts, and a step of detecting values, which are necessary for causing the X component, the Y component, and the Z component to become the predetermined amounts, as position error signals.

Assignees

• Hitachi Consumer Electronics

Inventors

• Yamazaki Kazuyoshi
• Ide Tatsuro

Classifications

• G11B7/1381

  Non-lens elements for altering the properties of the beam, e.g. knife edges, slits, filters or stops (G11B7/1353 - G11B7/1369 take precedence) · CPC title

• G11B7/08564

  using galvanomirrors · CPC title

• G11B7/083

  relative to record carriers storing information in the form of optical interference patterns, e.g. holograms · CPC title

• G11B7/1365

  Separate or integrated refractive elements, e.g. wave plates · CPC title

• G11B2007/0009

  for carriers having data stored in three dimensions, e.g. volume storage · CPC title