Optical information recording apparatus and method, optical information reproducing apparatus and method, optical information recording reproducing apparatus and method and optical information recording medium

• US 20040027968A1
• Filed: 08/06/2003
• Published: 02/12/2004
• Est. Priority Date: 10/12/2000
• Status: Abandoned Application

• Current Assignee: Optware Corporation
• Original Assignee: Optware Corporation
• Inventors: Horimai, Hideyoshi
• Application Number:
  US10/399,068
• Publication Number:
  US 20040027968A1
• Time in Patent Office: Days
• US Class Current: 369/103
• CPC Class Codes: G03H 1/0402 Recording geometries or arrangements G03H1/0443, G03H1/0476, G03H1/16 take precedence
• CPC Class Codes: G03H 1/0465 Particular recording light; Beam shape or geometry G03H1/06 takes precedence
• CPC Class Codes: G03H 1/16 using Fourier transform G03H1/10, G03H1/12, G03H1/14 take precedence; analogue computers G06G, e.g. G06G7/19
• CPC Class Codes: G03H 1/30 discrete holograms only
• CPC Class Codes: G03H 2001/0415 for recording reflection holograms
• CPC Class Codes: G11B 7/0065 Recording, reproducing or erasing by using optical interference patterns, e.g. holograms
• CPC Class Codes: G11B 7/007 Arrangement of the information on the record carrier, e.g. form of tracks , actual track shape, e.g. wobbled, or cross-section, e.g. v-shaped; Sequential information structures, e.g. sectoring or header formats within a track
• CPC Class Codes: G11B 7/00745 Sectoring or header formats within a track formats in general G11B20/12
• CPC Class Codes: G11B 7/00781 Auxiliary information, e.g. index marks, address marks, pre-pits, gray codes
• CPC Class Codes: G11B 7/08505 Methods for track change, selection or preliminary positioning by moving the head
• CPC Class Codes: G11B 7/08594 to access both sides of the disc with the same head assembly
• CPC Class Codes: G11B 7/0908 for focusing only G11B7/0925, G11B7/094, G11B7/0941, G11B7/0943, G11B7/0945, G11B7/0946, G11B7/0948 take precedence
• CPC Class Codes: G11B 7/128 Modulators G11B7/1245 takes precedence
• CPC Class Codes: G11B 7/131 Arrangement of detectors in a multiple array
• CPC Class Codes: G11B 7/24044 for storing optical interference patterns, e.g. holograms; for storing data in three dimensions, e.g. volume storage G11B7/24038 takes precedence
• CPC Class Codes: G11B 7/2405 being also used as track layers of pre-formatted layers tracks or pits G11B7/2407

Abstract

An object of the invention is to simplify the configuration of an optical system for recording or reproduction without causing a reduction in the amount of information. For recording, a spatial light modulator (27) generates information light by spatially modulating light according to information to be recorded. The information light is collected by an objective lens (21) and applied to an optical information recording medium (1) while converging to become minimum in diameter on the interface between a transparent substrate (2) and a protective layer (5). Recording-specific reference light is collected by an objective lens (31) and applied to the optical information recording medium (1) while converging to become minimum in diameter on the interface between the transparent substrate (2) and the protective layer (5). In an information recording layer (3), the information light and the recording-specific reference light interfere with each other to form an interference pattern. This interference pattern is volumetrically recorded in the information recording layer (3).

Claims

1. An optical information recording apparatus for recording information in an optical information recording medium having an information recording layer in which information is to be recorded through the use of holography, the apparatus comprising:

information light generating means for generating information light carrying information to be recorded;

recording-specific reference light generating means for generating recording-specific reference light; and

a recording optical system for applying the information light generated by the information light generating means and the recording-specific reference light generated by the recording-specific reference light generating means to the information recording layer so that information is recorded in the information recording layer in the form of an interference pattern resulting from interference between the information light and the recording-specific reference light,

wherein the recording optical system applies the information light and the recording-specific reference light coaxially to opposite sides of the information recording layer, letting the information light and the recording-specific reference light converge to become minimum in diameter at the same position.

2. An optical information recording apparatus according to claim 1, wherein:

the optical information recording medium has a positioning region in which information for positioning the information light and the recording-specific reference light is to be recorded; and

the recording optical system applies the information light and the recording-specific reference light, letting them converge to become minimum in diameter at a position along the thickness of the optical information recording medium where the positioning region is provided,

the optical information recording apparatus further comprising position control means for controlling the positions of the information light and the recording-specific reference light with respect to the optical information recording medium by using the information recorded in the positioning region.

3. An optical information recording apparatus according to claim 2, wherein the positioning region is located on an incidence side for the recording-specific reference light with respect to the information recording layer.

4. An optical information recording apparatus according to claim 1, wherein the information light generating means generates the information light by spatially modulating the recording-specific reference light having passed through the information recording layer based on the information to be recorded and reflecting the same.

5. An optical information recording apparatus according to claim 1, wherein the information light generating means spatially modulates the intensity of light based on the information to be recorded.

6. An optical information recording apparatus according to claim 1, wherein the information light generating means spatially modulates the phase of light based on the information to be recorded.

7. An optical information recording apparatus according to claim 1, wherein the recording-specific reference light generating means generates the recording-specific reference light having a spatially modulated phase.

8. An optical information recording apparatus according to claim 1, wherein the recording-specific reference light generating means generates the recording-specific reference light having a spatially modulated phase, and the information light generating means spatially modulates the phase of light in accordance with a phase modulation pattern determined based on the information to be recorded and a phase modulation pattern of the recording-specific reference light.

9. An optical information recording method for recording information in an optical information recording medium having an information recording layer in which information is to be recorded through the use of holography, the method comprising:

the step of generating information light carrying information to be recorded;

the step of generating recording-specific reference light; and

the recording step of applying the information light and the recording-specific reference light to the information recording layer so that information is recorded in the information recording layer in the form of an interference pattern resulting from interference between the information light and the recording-specific reference light, wherein

the recording step applies the information light and the recording-specific reference light coaxially to opposite sides of the information recording layer, letting the information light and the recording-specific reference light converge to become minimum in diameter at the same position.

10. An optical information reproducing apparatus for reproducing information through the use of holography from an optical information recording medium having an information recording layer in which information is recorded through the use of holography,

the optical information recording medium having a positioning region in which information for positioning reproduction-specific reference light is to be recorded, the positioning region being located on an incidence side for the reproduction-specific reference light with respect to the information recording layer, information being recorded in the information recording layer in the form of an interference pattern resulting from interference between information light and recording-specific reference light that are applied coaxially to opposite sides of the information recording layer, the information light and the recording-specific reference light converging to become minimum in diameter at a position along the thickness of the optical information recording medium where the positioning region is provided,

the optical information reproducing apparatus comprising:

reproduction-specific reference light generating means for generating the reproduction-specific reference light;

a reproducing optical system for applying the reproduction-specific reference light generated by the reproduction-specific reference light generating means to the information recording layer and for collecting reproduction light generated from the information recording layer upon application of the reproduction-specific reference light; and

detecting means for detecting the reproduction light collected by the reproducing optical system,

wherein the reproducing optical system applies the reproduction-specific reference light such that the reproduction-specific reference light becomes minimum in diameter at the position along the thickness of the optical information recording medium where the positioning region is provided, so that the application of the reproduction-specific reference light and the collection of the reproduction light are performed on an incidence side for the recording-specific reference light on the optical information recording medium, and that the reproduction-specific reference light and the reproduction light are arranged coaxially,

the optical information reproducing apparatus further comprising position control means for controlling the position of the reproduction-specific reference light with respect to the optical information recording medium by using the information recorded in the positioning region.

11. An optical information reproducing apparatus according to claim 10, wherein the reproduction light is light which is spatially modulated in intensity.

12. An optical information reproducing apparatus according to claim 10, wherein:

the reproduction light is light which is spatially modulated in phase;

the reproducing optical system generates composite light by superimposing the reproduction light on the reproduction-specific reference light; and

the detecting means detects the composite light.

13. An optical information reproducing apparatus according to claim 10, wherein the reproduction-specific reference light generating means generates the reproduction-specific reference light having a spatially modulated phase.

14. An optical information reproducing method for reproducing information through the use of holography from an optical information recording medium having an information recording layer in which information is recorded through the use of holography,

the optical information recording medium having a positioning region in which information for positioning reproduction-specific reference light is to be recorded, the positioning region being located on an incidence side for the reproduction-specific reference light with respect to the information recording layer, information being recorded in the information recording layer in the form of an interference pattern resulting from interference between information light and recording-specific reference light that are applied coaxially to opposite sides of the information recording layer, the information light and the recording-specific reference light converging to become minimum in diameter at a position along the thickness of the optical information recording medium where the positioning region is provided,

the optical information reproducing method comprising:

the step of generating the reproduction-specific reference light;

the reproducing step of applying the reproduction-specific reference light to the information recording layer and collecting reproduction light generated from the information recording layer upon application of the reproduction-specific reference light; and

the step of detecting the reproduction light collected by the reproducing optical system,

wherein the reproducing step applies the reproduction-specific reference light such that the reproduction-specific reference light becomes minimum in diameter at the position along the thickness of the optical information recording medium where the positioning region is provided, so that the application of the reproduction-specific reference light and the collection of the reproduction light are performed on an incidence side for the recording-specific reference light on the optical information recording medium, and that the reproduction-specific reference light and the reproduction light are arranged coaxially,

the optical information reproducing method further comprising the step of controlling the position of the reproduction-specific reference light with respect to the optical information recording medium by using the information recorded in the positioning region.

15. An optical information recording/reproducing apparatus for recording information in an optical information recording medium having an information recording layer in which information is to be recorded through the use of holography and for reproducing information from the optical information recording medium, the apparatus comprising:

information light generating means for generating information light carrying information to be recorded;

recording-specific reference light generating means for generating recording-specific reference light;

reproduction-specific reference light generating means for generating reproduction-specific reference light;

a recording/reproducing optical system for, when recording information, applying the information light generated by the information light generating means and the recording-specific reference light generated by the recording-specific reference light generating means to the information recording layer so that information is recorded in the information recording layer in the form of an interference pattern resulting from interference between the information light and the recording-specific reference light and, when reproducing information, applying the reproduction-specific reference light generated by the reproduction-specific reference light generating means to the information recording layer and collecting reproduction light generated from the information recording layer upon application of the reproduction-specific reference light; and

detecting means for detecting the reproduction light collected by the recording/reproducing optical system,

wherein the recording/reproducing optical system applies, when recording information, the information light and the recording-specific reference light coaxially to opposite sides of the information recording layer, letting the information light and the recording-specific reference light converge to become minimum in diameter at the same position, and, when reproducing information, applies the reproduction-specific reference light such that the reproduction-specific reference light becomes minimum in diameter at the position along the thickness of the optical information recording medium where the recording-specific reference light becomes minimum in diameter, so that the application of the reproduction-specific reference light and the collection of the reproduction light are performed on an incidence side for the recording-specific reference light on the optical information recording medium, and that the reproduction-specific reference light and the reproduction light are arranged coaxially.

16. An optical information recording/reproducing apparatus according to claim 15, wherein:

the optical information recording medium has a positioning region in which information for positioning the information light, the recording-specific reference light, and the reproduction-specific reference light is to be recorded; and

the recording/reproducing optical system applies the information light, the recording-specific reference light, and the reproduction-specific reference light, letting them converge to become minimum in diameter at a position along the thickness of the optical information recording medium where the positioning region is provided,

the optical information recording/reproducing apparatus further comprising position control means for controlling, when recording information, the positions of the information light and the recording-specific reference light with respect to the optical information recording medium by using the information recorded in the positioning region, and, when reproducing information, the position of the reproduction-specific reference light with respect to the optical information recording medium by using the information recorded in the positioning region.

17. An optical information recording/reproducing apparatus according to claim 16, wherein the positioning region is located on the incidence side for the recording-specific reference light and the reproduction-specific reference light with respect to the information recording layer.

18. An optical information recording/reproducing apparatus according to claim 15, wherein the information light generating means generates the information light by spatially modulating the recording-specific reference light having passed through the information recording layer based on the information to be recorded and reflecting the same.

19. An optical information recording/reproducing apparatus according to claim 15, wherein the information light generating means spatially modulates the intensity of light based on the information to be recorded.

20. An optical information recording/reproducing apparatus according to claim 15, wherein:

the information light generating means spatially modulates the phase of light based on the information to be recorded;

the recording/reproducing optical system generates composite light by superimposing the reproduction light on the reproduction-specific reference light; and

the detecting means detects the composite light.

21. An optical information recording/reproducing apparatus according to claim 15, wherein the recording-specific reference light generating means generates the recording-specific reference light having a spatially modulated phase, and the reproduction-specific reference light generating means generates the reproduction-specific reference light having a spatially modulated phase.

22. An optical information recording/reproducing apparatus according to claim 15, wherein:

the recording-specific reference light generating means generates the recording-specific reference light having a spatially modulated phase;

the information light generating means spatially modulates the phase of light in accordance with a phase modulation pattern determined based on the information to be recorded and a phase modulation pattern of the recording-specific reference light;

the reproduction-specific reference light generating means generates the reproduction-specific reference light having a spatially modulated phase;

the recording/reproducing optical system generates composite light by superimposing the reproduction light on the reproduction-specific reference light; and

the detecting means detects the composite light.

23. An optical information recording/reproducing method for recording information in an optical information recording medium having an information recording layer in which information is to be recorded through the use of holography and for reproducing information from the optical information recording medium, the method comprising:

the step of generating information light carrying information to be recorded;

the step of generating recording-specific reference light;

the recording step of applying the information light generated by the information light generating means and the recording-specific reference light generated by the recording-specific reference light generating means to the information recording layer so that information is recorded in the information recording layer in the form of an interference pattern resulting from interference between the information light and the recording-specific reference light;

the step of generating reproduction-specific reference light;

the reproducing step of applying the reproduction-specific reference light to the information recording layer and collecting reproduction light generated from the information recording layer upon application of the reproduction-specific reference light; and

the step of detecting the reproduction light, wherein;

the recording step applies the information light and the recording-specific reference light coaxially to opposite sides of the information recording layer, letting the information light and the recording-specific reference light converge to become minimum in diameter at the same position; and

the reproducing step applies the reproduction-specific reference light such that the reproduction-specific reference light becomes minimum in diameter at the position along the thickness of the optical information recording medium where the recording-specific reference light becomes minimum in diameter, so that the application of the reproduction-specific reference light and the collection of the reproduction light are performed on an incidence side for the recording-specific reference light on the optical information recording medium, and that the reproduction-specific reference light and the reproduction light are arranged coaxially.

24. An optical information recording medium comprising:

an information recording layer in which information is to be recorded through the use of holography;

a first surface on which recording-specific reference light and reproduction-specific reference light are incident and from which reproduction light exits;

a second surface on which information light carrying information to be recorded is incident; and

a positioning region in which information for