Optical recording apparatus and optical recording/reproducing apparatus

• US 7,064,875 B2
• Filed: 09/12/2003
• Issued: 06/20/2006
• Est. Priority Date: 03/24/2003
• Status: Expired due to Fees

• Current Assignee: Fuji Xerox Company Limited (Xerox Holdings Corp.)
• Original Assignee: Fuji Xerox Company Limited (Xerox Holdings Corp.)
• Inventors: Ishii, Tsutomu, Yasuda, Shin, Minabe, Jiro, Kawano, Katsunori, Maruyama, Tatsuya, Matsui, Norie, Hama, Kazuhiro
• Primary Examiner(s): Cherry, Euncha P.
• Application Number:
  US10/660,485
• Publication Number:
  US 20040190094A1
• Time in Patent Office: 1,012 Days
• Field of Search: 359/11, 359/30, 359/31, 359/35
• US Class Current: 359/11
• CPC Class Codes: G03H 2222/31 Polarised light
• CPC Class Codes: G11B 7/0065 Recording, reproducing or erasing by using optical interference patterns, e.g. holograms
• CPC Class Codes: G11B 7/128 Modulators G11B7/1245 takes precedence
• CPC Class Codes: G11B 7/1353 Diffractive elements, e.g. holograms or gratings diffraction gratings per se G02B5/18; holograms per se G02B5/32; grating systems G02B27/44
• CPC Class Codes: G11B 7/1356 Double or multiple prisms, i.e. having two or more prisms in cooperation
• CPC Class Codes: G11B 7/1369 Active plates, e.g. liquid crystal panels or electrostrictive elements
• CPC Class Codes: G11B 7/245 containing a polymeric component
• CPC Class Codes: G11B 7/2467 azo-dyes
• CPC Class Codes: G11B 7/25 containing liquid crystals
• CPC Class Codes: G11B 7/2531 comprising glass
• CPC Class Codes: G11B 7/2533 comprising resins
• CPC Class Codes: G11B 7/2534 polycarbonates [PC]
• CPC Class Codes: G11B 7/2535 polyesters, e.g. PET, PETG or PEN

Abstract

An optical recording/reproducing apparatus having excellent resistance against vibration and noise is provided. In recording, coherent light is polarization-modulated with a spatial light modulator to generate signal light and reference light whose polarization directions are crossed at right angles with each other. The signal light permeates a polarizing beam splitter, and is incident to a quarter wavelength plate. The reference light passes through a passing hole, is diffused by a light diffuser and is incident to the quarter wavelength plate. The reference and signal light are converted into circularly polarized light which revolve in directions opposite to each other and condensed by a condenser lens, and then a predetermined area of an optical recording medium is irradiated with the reference and signal light. Thus, the reference and signal light are generated by modulating the incident light from the same light source and are coaxially incident to the polarizing beam splitter.

Claims

1. An optical recording apparatus for recording a hologram in an optical recording medium, comprising:

a spatial light modulator which modulates light incident from a single light source and generates signal light and reference light, the spatial light modulator modulating the signal light according to a signal to be recorded in the optical recording medium to cause a polarization direction of the signal light to have a predetermined polarization direction and to cause a polarization direction of the reference light to have a direction crossed at right angles with the predetermined polarization direction;

a wavelength plate which converts the signal light and the reference light, which have been generated by the spatial light modulator, into circularly polarized light in which the signal light and the reference light revolve in directions opposite to each other; and

a condensing optical system which condenses the circularly polarized light, which has been converted by the wavelength plate and in which the signal light and the reference light revolve in directions opposite to each other, into a predetermined area of the optical recording medium.

2. An optical recording apparatus according to claim 1, wherein a holographic optical element for forming a predetermined wavefront for the reference light is further arranged between the spatial light modulator and the wavelength plate.

3. An optical recording apparatus according to claim 2, wherein the holographic optical element is a light diffuser which diffuses the reference light.

4. An optical recording apparatus according to claim 1, wherein the spatial light modulator comprises a transmissive liquid crystal cell in which transparent electrodes are formed on both surfaces of a plate-shaped liquid crystal, a first polarizing plate which is arranged on a light incident side of the liquid crystal cell and transmits light of the predetermined polarization direction, and a second polarizing plate which is arranged on a light outgoing side of the liquid crystal cell and transmits light of any polarization direction at a substantially central portion thereof and transmits light of the predetermined polarization direction at a portion thereof surrounding the substantially central portion.

5. An optical recording apparatus according to claim 4, wherein the spatial light modulator is a liquid crystal panel for a projector.

6. An optical recording apparatus according to claim 1, wherein a signal light and the reference light are coaxially transmitted through the special light modulator, the wave length plate, and the condensing optical system.

7. An optical recording/reproducing apparatus comprising:

a spatial light modulator which modulates light incident from a single light source and generates signal light and reference light, the spatial light modulator modulating the signal light according to a signal to be recorded in an optical recording medium to cause a polarization direction of the signal light to have a predetermined polarization direction and to cause a polarization direction of the reference light to have a polarization direction crossed at right angles with the predetermined polarization direction;

a polarizing beam splitter which transmits light incident from the spatial light modulator irrespective of a polarization direction thereof, the polarizing beam splitter reflecting reproducing light incident from the optical recording medium toward a predetermined direction according to a polarization direction thereof and transmitting the light incident from the optical recording medium except for the reproducing light irrespective of a polarization direction thereof;

a wavelength plate which converts linearly polarized light incident from the polarizing beam splitter into circularly polarized light and converts circularly polarized light into linearly polarized light; and

a condensing optical system which condenses light incident from the wavelength plate into a predetermined area of the optical recording medium,

wherein in the case that a hologram is to be recorded in the optical recording medium, the spatial light modulator generates the signal light and the reference light, the wavelength plate converts the generated signal light and the generated reference light into circularly polarized light in which the signal light and the reference light revolve in directions opposite to each other, and the condensing optical system condenses the circularly polarized light, which is converted with the wavelength plate and in which the signal light and the reference light revolve in directions opposite to each other, into a predetermined area of the optical recording medium, and

in the case that a hologram recorded in the optical recording medium is to be reproduced, the spatial light modulator generates the reference light, the wavelength plate converts the generated reference light into circularly polarized light, the condensing optical system condenses the circularly polarized light, which is converted by the wavelength plate, into a predetermined area of the optical recording medium, the wavelength plate converts obtained reproducing light into linearly polarized light, and the polarizing beam splitter reflects the converted linearly polarized light toward a predetermined direction.

8. An optical recording/reproducing apparatus according to claim 7, wherein a holographic optical element for forming a predetermined wavefront for the reference light is further arranged between the spatial light modulator and the wavelength plate.

9. An optical recording/reproducing apparatus according to claim 8, wherein the holographic optical element is a light diffuser which diffuses the reference light.

10. An optical recording/reproducing apparatus according to claim 7, wherein the spatial light modulator comprises a transmissive liquid crystal cell in which transparent electrodes are formed on both surfaces of a plate-shaped liquid crystal, a first polarizing plate which is arranged on a light incident side of the liquid crystal cell and transmits light of the predetermined polarization direction, and a second polarizing plate which is arranged on a light outgoing side of the liquid crystal cell and transmits light of any polarization direction at a substantially central portion thereof and transmits light of the predetermined polarization direction at a portion thereof surrounding the substantially central portion.

11. An optical recording/reproducing apparatus according to claim 10, wherein the spatial light modulator is a liquid crystal panel for a projector.

12. An optical recording/reproducing apparatus according to claim 10, wherein the polarizing beam splitter has a passing hole having a diameter corresponding to the substantially central portion of the second polarizing plate.

13. An optical recording/reproducing apparatus according to claim 7, wherein a signal light and the reference light are coaxially transmitted through the special light modulator, the wave length plate, and the condensing optical system.