Title:
HIGH-DENSITY OPTICAL MEMORY SYSTEM
Document Type and Number:
Japanese Patent JP3789692
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To provide a high-density optical memory system which contributes to an improvement in multiple-valued detection accuracy.
SOLUTION: The high-density optical memory system using a double refractive recording film and multiple-valued encoding reads out the information on depth as a phase difference between orthogonal polarized light rays by providing the double refractive film (for instance, polyimide fluoride) with parts of depths of multiple stages. If the numerical aperture NA of a condenser lens of a read-out optical system is small in this case, the influence by diffraction is high but the characteristic of a nearly monotonous decrease may be obtained and the multiple-valued is made possible by using a lens of NA≥0.8.
Inventors:
Yasuo Kokubun
Hisao Nakajima
Tomotaka Yamaguchi
Hisao Nakajima
Tomotaka Yamaguchi
Application Number:
JP27366699A
Publication Date:
June 28, 2006
Filing Date:
September 28, 1999
Export Citation:
Assignee:
Japan Science and Technology Agency
International Classes:
G11B7/005; G11B7/24; G11B7/013; G11B7/135; (IPC1-7): G11B7/005; G11B7/135; G11B7/24
Domestic Patent References:
| JP11238251A | ||||
| JP2236525A |
Attorney, Agent or Firm:
Mamoru Shimizu
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