US4956812A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Wavelength selective optical recording and reproducing device
Assignee: Mitsubishi Electric Corp
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Filing: 1988-06-20
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Granted: 1990-09-11
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Expires: 2008-06-20
Abstract
Abstract A wavelength selective optical recording and reproducing device has a reference wavelength in a marker hole of a medium. The optical detector is adapted to detect light which is reflected from or transmitted through the marker hole. A phase detector detects the phase of an output of the optical detector by using a high frequency signal as a reference to obtain a signal indicative of the deviation of the wavelength of the output from a desired wavelength. A wavelength regulator is responsive to the wavelength deviation to control the wavelength of the light source to be the desired wavelength.
Inventors
- 👤 Masatomo Seya
- 👤 Kazuo Okada
- 👤 Motomu Yoshimura
- 👤 Mitsuo Maeda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 16:52
CPC Classifications
G; G11; G11B; G11B7/00; G11B7/004; G11B7/0045; G11B7/00453
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
150 words
A wavelength selective optical recording and reproducing device comprising: a light source having a variable wavelength; a recording and reproducing medium for storing information, said information being selectively retrieved according to the wavelength of light; an optical system for condensing light from said light source and illuminating said medium; optical detector means for detecting light from said medium, said optical detector producing a data signal when the detected light is at a predetermined wavelength; a frequency generator producing a constant frequency signal; phase detector means receiving said constant frequency signal and said data signal and producing a phase difference signal in response thereto; controller means receiving said phase difference signal and being controlled thereby to produce an output; and adder means connected to said light source for adding said constant frequency signal to the output of said controller to produce a signal for controlling the wavelength of said light source.
Claim 2
Dependent Claim
150 words
A wavelength selective optical recording and reproducing device comprising: a light source having a variable wavelength; a recording and reproducing medium for storing information, said information being selectively retrieved according to the wavelength of light; an optical system for condensing light from said light source and illuminating said medium; optical detector means for detecting light from said medium, said optical detector producing a data signal when the detected light is at a predetermined wavelength; a frequency generator producing a constant frequency signal; phase detector means receiving said constant frequency signal and said data signal and producing a phase difference signal in response thereto; controller means receiving said phase difference signal and being controlled thereby to produce an output; and adder means connected to said light source for adding said constant frequency signal to the output of said controller to produce a signal for controlling the wavelength of said light source.
Claim 3
Dependent Claim
36 words
The device according to claim 1, wherein said medium contains a plurality of regions with data being recorded once in each region so that data may be detected a plurality of times per revolution of medium.
Claim 4
Dependent Claim
13 words
The device according to claim 2, wherein said medium contains coaxial guide grooves.
Claim 5
Dependent Claim
13 words
The device according to claim 2, wherein said medium contains spiral guide grooves.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-09-10 | 1994-03-12 | 1994-09-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-09-10 | 1998-03-12 | 1998-09-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-09-10 | 2002-03-12 | 2002-09-11 | $7700.00 | Window Closed / Lapsed |