US5339306A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Detecting interferential diffraction of a reflected beam from a polymer liquid crystal recording medium
Assignee: Canon Inc
•
Filing: 1992-06-03
•
Granted: 1994-08-16
•
Expires: 2012-06-03
Abstract
Abstract A memory medium includes a memory layer of a polymer liquid crystal and a reflection layer disposed on a substrate. A record part having a different refractive index from that of a non-record part is formed in the memory layer so that the record part and the non-record part have a difference in optical thickness of the memory layer. In a reproduction step, the memory medium is irradiated with a reproduction beam of coherent light so that the reproduction beam is transmitted through the memory layer, reflected at the reflection layer and re-transmitted through the memory layer, during which the reproduction beam is subjected to interferential diffraction due to the optical thickness difference between the record part and the non-record part to allow readout of the recorded data.
Inventors
- 👤 Kazuo Yoshinaga
- 👤 Katsuya Oikawa
- 👤 Toshikazu Ohnishi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 23:48
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/24; G11B7/241; G11B7/242; G11B7/244; G11B7/245; G11B7/004; G11B7/005; G11B7/0051; G11B7/246; G11B7/247; G11B7/25; G11B7/252; G11B7/253; G11B7/2531; G11B7/2533; G11B7/257; G11B7/2572; G11B7/258; G11B7/2585; G11B7/259; G11B7/2595
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
104 words
An information reproduction apparatus, comprising: a memory medium including a memory layer comprising a polymer liquid crystal and a reflection layer disposed on a substrate, the memory layer comprising a record pit formed by irradiation with a writing optical beam, thereby providing said pit with a width and a refractive index which is different from that of a neighboring non-record part, a means for irradiating the record pit with a reproducing optical beam having a spot diameter larger than the width of the record pit, and a means for detecting interferential diffraction of a reflected beam from the record pit to reproduce recorded data.
Claim 2
Dependent Claim
104 words
An information reproduction apparatus, comprising: a memory medium including a memory layer comprising a polymer liquid crystal and a reflection layer disposed on a substrate, the memory layer comprising a record pit formed by irradiation with a writing optical beam, thereby providing said pit with a width and a refractive index which is different from that of a neighboring non-record part, a means for irradiating the record pit with a reproducing optical beam having a spot diameter larger than the width of the record pit, and a means for detecting interferential diffraction of a reflected beam from the record pit to reproduce recorded data.
Claim 3
Dependent Claim
16 words
A apparatus according to claim 1, wherein said polymer liquid crystal has a glass transition point.
Claim 4
Dependent Claim
16 words
An apparatus according to claim 1, wherein said optical beam has a radial Gaussian intensity distribution.
Claim 5
Dependent Claim
29 words
An apparatus according to claim 1, further comprising: a writing means for irradiating the memory layer with a writing beam to form in the memory layer said record pit.
Claim 6
Dependent Claim
23 words
An apparatus according to claim 4, wherein the width of the record pit is smaller than the spot diameter of the writing beam.
Claim 7
Dependent Claim
22 words
An apparatus according to claim 5, wherein the writing beam and the reproducing optical beam are issued from a single light source.
Claim 8
Dependent Claim
23 words
An apparatus according to claim 6, wherein the writing beam and the reproducing optical beam have different light intensities and/or different pulse durations.
References Cited (Backward Citations)
US4115809A
Cited
US4305081A
Cited
US4329697A
Cited
US4398203A
Cited
JPS5910930A
Cited
JPS5935989A
Cited
US4933243A
Cited
JPS62154340A
Cited
JPS6440380A
Cited
US4965591A
Cited
JPH01162245A
Cited
JPH0259394A
Cited
US5019476A
Cited
US5141785A
Cited
US5124183A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-08-15 | 1998-02-14 | 1998-08-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-08-15 | 2002-02-14 | 2002-08-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-08-15 | 2006-02-14 | 2006-08-16 | $7700.00 | Window Closed / Lapsed |