US5438561A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for recording and reproducing information using an optical memory
Assignee: Sharp Corp
•
Filing: 1994-10-26
•
Granted: 1995-08-01
•
Expires: 2014-10-26
Abstract
Abstract A method for recording and reproducing information using an optical memory device being constituted by a transparent substrate, a recording film formed on the substrate and made of a resin containing a photochromic material dispersed therein, the photochromic material being capable of reversibly changing its state from achromatic to chromatic and absorbing light of at least 780 nm wavelength in the chromatic state, and a reflecting film formed on the recording film for reflecting light, the method including the steps of: applying a visible light beam of a long wavelength onto the optical memory device to turn said recording film into the achromatic state for initialization, applying thereafter a visible light beam of a short wavelength onto the optical memory device to turn the recording film into the chromatic state in accordance with binary-coded data of information for recording the information, and applying another visible light beam of a long wavelength having a light intensity lower than that of the visible light beam for initialization onto the optical memory device for reproducing the information having been recorded therein.
Inventors
- 👤 Kazuo Van
- 👤 Kenji Ohta
- 👤 Toshio Ishikawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 04:21
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/24; G11B7/241; G11B7/252; G11B7/258; G11B7/004; G11B7/0045; G11B7/00455; G11B7/005; G11B7/0052; G11B7/0055; G11B7/00552; G11B7/242; G11B7/244; G11B7/245; G11B7/253; G11B7/2531; G11B7/2533; G11B7/2534; G11B7/2585; G11B7/2595
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
234 words
A method of recording and reproducing information using an optical memory device comprising a transparent substrate, a recording film formed on said substrate and made of a resin containing a photochromic material dispersed therein, said photochromic material being capable of reversibly changing its state from achromatic to chromatic and absorbing light of at least 780 nm wavelength in the chromatic state, and a reflecting film formed on said recording film for reflecting light, said method comprising the steps of: applying a visible light beam of a long wavelength onto said optical memory device to turn said recording film into the achromatic state for initialization, applying thereafter a visible light beam of a short wavelength onto said optical memory device to turn said recording film into the chromatic state in accordance with binary-coded data of information for recording said information, and applying another visible light beam of a long wavelength having a light intensity lower than that of said visible light beam for initialization onto said optical memory device for reproducing said information having been recorded therein, the information being reproduced by using a difference in the light intensity between the light reflected by a chromatic region in which information is recorded and the light reflected by an achromatic region in which information is not recorded, the light intensity reflected by the chromatic region being smaller than the light intensity reflected by the achromatic region.
Claim 2
Independent Claim
234 words
A method of recording and reproducing information using an optical memory device comprising a transparent substrate, a recording film formed on said substrate and made of a resin containing a photochromic material dispersed therein, said photochromic material being capable of reversibly changing its state from achromatic to chromatic and absorbing light of at least 780 nm wavelength in the chromatic state, and a reflecting film formed on said recording film for reflecting light, said method comprising the steps of: applying a visible light beam of a long wavelength onto said optical memory device to turn said recording film into the achromatic state for initialization, applying thereafter a visible light beam of a short wavelength onto said optical memory device to turn said recording film into the chromatic state in accordance with binary-coded data of information for recording said information, and applying another visible light beam of a long wavelength having a light intensity lower than that of said visible light beam for initialization onto said optical memory device for reproducing said information having been recorded therein, the information being reproduced by using a difference in the light intensity between the light reflected by a chromatic region in which information is recorded and the light reflected by an achromatic region in which information is not recorded, the light intensity reflected by the chromatic region being smaller than the light intensity reflected by the achromatic region.
Claim 3
Dependent Claim
28 words
The method of claim 1, wherein the visible light beam of a short wavelength used for recording the information has mainly a wavelength of 400 to 500 nm.
Claim 4
Dependent Claim
28 words
The method of claim 1, wherein the visible light beam of a long wavelength used for reproducing the information has mainly a wavelength of 600 to 800 nm.
Claim 5
Dependent Claim
43 words
The method of claim 1, wherein the visible light beam of a long wavelength used for reproducing the information has a light intensity as low as 1/5 to 1/100 of that of the visible light beam of a long wavelength used for initialization.
Claim 6
Dependent Claim
18 words
The method of claim 1, wherein the reflecting film is formed from Al or Au by vapor deposition.
Claim 7
Dependent Claim
15 words
The method of claim 1, wherein the photochromic material is a diallylethene derivative or nitrospirothiopyran.
Claim 8
Dependent Claim
22 words
The method of claim 1, wherein the information recorded in the optical memory device is reproducible using a commercially available CD-player system.
Claim 9
Dependent Claim
20 words
The method of claim 1 wherein the photochromic material has an absorption peak at a wavelength of about 780 nm.
Claim 10
Dependent Claim
22 words
The method of claim 1 wherein the photochromic material has an absorption peak at a predetermined wavelength within the visible light spectrum.
References Cited (Backward Citations)
US4403318A
Cited
JPS62165751A
Cited
JPS62165747A
Cited
JPS62165748A
Cited
US4864536A
Cited
US5142493A
Cited
EP0353391A2
Cited
US5088086A
Cited
EP0373939A1
Cited
US5113387A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1998-07-31 | 1999-01-30 | 1999-08-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2002-07-31 | 2003-01-30 | 2003-08-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2006-07-31 | 2007-01-30 | 2007-08-01 | $7700.00 | Window Closed / Lapsed |