US3787887A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Optical recorder with intensity control
Assignee: RCA Corp
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Filing: 1971-04-29
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Granted: 1974-01-22
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Expires: 1991-04-29
Abstract
Abstract Disclosed is a control circuit for establishing a reference level at the output of an optical modulator used to modulate the intensity of a laser beam. The modulated beam is sampled in the presence of a predetermined signal applied to the modulator to detect deviation from a known relationship; and means provided to correct for such deviation and re-establish said known relationship.
Inventors
- 👤 G Burton
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 00:37
CPC Classifications
G; G06; G06K; G06K15/00; G06K15/02; G06K15/12; G06K15/1204; G06K15/1209; G06K15/1214; G01; G01D; G01D15/00; G01D15/14; G02; G02F; G02F1/00; G02F1/01; G02F1/0121; G02F1/0123; H; H04; H04N; H04N1/00; H04N1/40; H04N1/407
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
364 words
In a signal recording system including means for providing a light beam optically coupled to optical modulator means for intensity modulating said light beam in response to electrical input signals coupled to said optical modulator means, said intensity modulated light beam to be recorded on a light sensitive medium by focusing said intensity modulated light beam into a high energy density recording spot and scanning said light sensitive medium with said recording spot, the combination comprising, control means electrically coupled to said optical modulator means for controlling said intensity modulated light beam in accordance with the instantaneous level of said electrical input signals coupled to said modulator, said electrical input signals including a signal level component for determining said light information pattern and a bias level component having a magnitude determining said intensity of said intensity modulated light beam causing a reference black level to be recorded on said light sensitive medium in the absence of said signal level component, and feedback means optically coupled to said optical modulator means and electrically coupled to said control means, said feedback means including sampling means optically coupled to said optical modulator for sampling a portion of said light beam from said optical modulator, optical means coupled to said sampling means for resolving said sampled portion into first and second mutually orthogonal light beam components having a desired relationship in accordance with said input signals, averaging means coupled to said first and second light beam components for providing an average intensity signal indicating the average intensity of said first and second light beam components, and an amplitude comparator means for detecting intensity differences between the intensity of said first component of said intensity modulated light beam and the average intensity of said first and second light beam components and generating an amplitude comparator output electrical signal in accordance with said intensity differences whereby said feedback means automaTically adjusts and maintains, said bias level component applied to said optical modulator means at said magnitude which, in the absence of said signal level component, results in said intensity of said intensity modulated light beam being substantially that intensity which produces said reference black level on said light sensitive medium.
Claim 2
Dependent Claim
364 words
In a signal recording system including means for providing a light beam optically coupled to optical modulator means for intensity modulating said light beam in response to electrical input signals coupled to said optical modulator means, said intensity modulated light beam to be recorded on a light sensitive medium by focusing said intensity modulated light beam into a high energy density recording spot and scanning said light sensitive medium with said recording spot, the combination comprising, control means electrically coupled to said optical modulator means for controlling said intensity modulated light beam in accordance with the instantaneous level of said electrical input signals coupled to said modulator, said electrical input signals including a signal level component for determining said light information pattern and a bias level component having a magnitude determining said intensity of said intensity modulated light beam causing a reference black level to be recorded on said light sensitive medium in the absence of said signal level component, and feedback means optically coupled to said optical modulator means and electrically coupled to said control means, said feedback means including sampling means optically coupled to said optical modulator for sampling a portion of said light beam from said optical modulator, optical means coupled to said sampling means for resolving said sampled portion into first and second mutually orthogonal light beam components having a desired relationship in accordance with said input signals, averaging means coupled to said first and second light beam components for providing an average intensity signal indicating the average intensity of said first and second light beam components, and an amplitude comparator means for detecting intensity differences between the intensity of said first component of said intensity modulated light beam and the average intensity of said first and second light beam components and generating an amplitude comparator output electrical signal in accordance with said intensity differences whereby said feedback means automaTically adjusts and maintains, said bias level component applied to said optical modulator means at said magnitude which, in the absence of said signal level component, results in said intensity of said intensity modulated light beam being substantially that intensity which produces said reference black level on said light sensitive medium.
Claim 3
Dependent Claim
132 words
The invention according to claim 1 wherein the averaging means of said feedback means includes means for transforming each of said first and second light beam components respectively into corresponding first and second electrical signals, and wherein said amplitude comparator means and said averaging means further includes circuit means coupled to said transforming means for monitoring said first and second electrical signals to detect a deviation from a desired relationship between said signals; and wherein said control means further includes means electrically coupled to said circuit means and operable during a given portion of said input signal applied to said optical modulator to cause the operation of said optical modulator to be adjusted to establish and maintain said desired relationship between said first and second components for providing said reference black level.
References Cited (Backward Citations)
US3562422A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-01-21 | 1977-07-23 | 1978-01-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-01-21 | 1981-07-23 | 1982-01-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-01-21 | 1985-07-23 | 1986-01-22 | $7700.00 | Window Closed / Lapsed |