US4979044A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic contrast circuit for instantaneous compensation
Assignee: Samsung Electronics Co Ltd
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Filing: 1989-02-13
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Granted: 1990-12-18
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Expires: 2009-02-13
Abstract
Abstract An automatic contrast control circuit for a television receiver detects the variations in video signal brightness to compensate the brightness and contrast by supplying as a contrast control signal a direct voltage output which is a composite of the brightness signal and a limited beam current from an automatic brightness limiter circuit (ABL), thus it is possible to obtain a reproduced image with a sharp contrast without the shake of the image.
Inventors
- 👤 Sung-Pyo Hong
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 23:52
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/44; H04N5/57; H04N5/59
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
118 words
An automatic contrast circuit for instantaneous compensation comprising: a luminance signal amplifying means having a device for amplifying a brightness signal applied thereto from a luminance processing means through a bias resistor; an automatic brightness limiter circuit included in a flyback transformer for supplying a beam current having a limited brightness; an inverting amplifier circuit connected between the luminance signal amplifying means and the brightness limiter circuit for producing a composite signal of said beam current and said brightness signal; and a direct voltage control means connected to the output side of the inverting amplifier circuit for supplying a divided voltage from a voltage source together with the composite signal as a control signal for a contrast controller.
Claim 2
Dependent Claim
118 words
An automatic contrast circuit for instantaneous compensation comprising: a luminance signal amplifying means having a device for amplifying a brightness signal applied thereto from a luminance processing means through a bias resistor; an automatic brightness limiter circuit included in a flyback transformer for supplying a beam current having a limited brightness; an inverting amplifier circuit connected between the luminance signal amplifying means and the brightness limiter circuit for producing a composite signal of said beam current and said brightness signal; and a direct voltage control means connected to the output side of the inverting amplifier circuit for supplying a divided voltage from a voltage source together with the composite signal as a control signal for a contrast controller.
Claim 3
Dependent Claim
55 words
An automatic contrast circuit for instantaneous compensation according to claim 1 wherein the inverting amplifier circuit includes a variable resistor and bias resistors connected to the automatic brightness limiter circuit, and transistors for differential amplification connected to the bias resistors to generate a DC voltage of the automatic brightness limiter circuit and a luminance signal.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-12-17 | 1994-06-18 | 1994-12-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-12-17 | 1998-06-18 | 1998-12-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-12-17 | 2002-06-18 | 2002-12-18 | $7700.00 | Window Closed / Lapsed |