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US4682231A Expired / Lapsed US ⏱️ 0.0 years remaining

Brightness and contrast adjusting apparatus

Assignee: Sony Corp
•
Filing: 1985-06-21
•
Granted: 1987-07-21
•
Expires: 2005-06-21
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Abstract

Abstract A brightness and contrast adjusting apparatus which adjusts the brightness and contrast of a cathode ray tube of a television receiver, comprises an inserting circuit (2) for inserting first and second reference signals P C and P Y into a video signal, a variable amplifier (5) for amplifying this video signal, a gain adjusting circuit for detecting the first reference signal P C from the output of the variable amplifier (5) and for adjusting the gain of the variable amplifier (5) such that the magnitude of the detected signal becomes equal to a predetermined value, a circuit for supplying the output of the variable amplifier (5) to a cathode ray tube (11), a brightness adjusting circuit for detecting the second reference signal P Y and for adjusting the brightness of the cathode ray tube (11) in response to the magnitude of the second reference signal P Y detected, adjusting circuits (21) and (23) for varying the levels of the first and second reference signals P C and P Y , and a constant multiplier circuit (24) for making the level of the second reference signal P Y equal to a constant multiple of the level of the first reference signal P C . According to this apparatus, it is possible to adjust the contrast and the brightness independently.

Inventors

  • 👤 Yoshifumi Yamakawa

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-31 19:08
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/44; H04N5/57

Claims Analysis

Total Claims: 6
Claim 1
Independent Claim 170 words
A brightness and contrast adjusting apparatus, which is characterized in that the apparatus comprises an inserting circuit for inserting first and second reference signals to a video signal, a variable amplifier for amplifying said references inserted video signal, a gain adjusting circuit for detecting said first reference signal from an output of said variable amplifier and for adjusting a gain of said variable amplifier such that a magnitude of said detected first reference signal becomes equal to a predetermined value, a circuit for supplying the outlet of said variable amplifier to a cathode ray tube, a brightness adjusting circuit for detecting said second reference signal from said supplying circuit and for adjusting a brightness of said cathode ray tube in response to a magnitude of said detected second reference signal, an adjusting circuit for varying levels of said first and second reference signals, and a constant multiplier circuit for making the level of said second reference signal equal to a constant multiple of the level of said first reference signal.
Claim 2
Dependent Claim 170 words
A brightness and contrast adjusting apparatus, which is characterized in that the apparatus comprises an inserting circuit for inserting first and second reference signals to a video signal, a variable amplifier for amplifying said references inserted video signal, a gain adjusting circuit for detecting said first reference signal from an output of said variable amplifier and for adjusting a gain of said variable amplifier such that a magnitude of said detected first reference signal becomes equal to a predetermined value, a circuit for supplying the outlet of said variable amplifier to a cathode ray tube, a brightness adjusting circuit for detecting said second reference signal from said supplying circuit and for adjusting a brightness of said cathode ray tube in response to a magnitude of said detected second reference signal, an adjusting circuit for varying levels of said first and second reference signals, and a constant multiplier circuit for making the level of said second reference signal equal to a constant multiple of the level of said first reference signal.
Claim 3
Dependent Claim 35 words
A brightness and contrast adjusting apparatus according to claim 1, said brightness and contrast adjusting apparatus being characterized in that said first reference signal is inserted into a horizontal blanking period of said video signal.
Claim 4
Dependent Claim 42 words
A brightness and contrast adjusting apparatus according to claim 1, said brightness and contrast adjusting apparatus being characterized in that said first reference signal is inserted into a horizontal blanking period of a plurality of consecutive horizontal periods of said video signal.
Claim 5
Dependent Claim 39 words
A brightness and contrast adjusting apparatus according to claim 1, said brightness and contrast adjusting apparatus being characterized in that said second reference signal is inserted into a horizontal period of said video signal outside an effective picture screen.
Claim 6
Dependent Claim 41 words
A brightness and contrast adjusting apparatus according to claim 1, said brightness and contrast adjusting apparatus being characterized in that said second reference signal is inserted over a plurality of horizontal periods of the video signal outside an effective picture screen.

References Cited (Backward Citations)

US3760099A Cited
JPS4946332A Cited
US3873767A Cited
GB1585063A Cited
US4204229A Cited
JPS5871775A Cited
US4587554A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1990-07-20 1991-01-19 1991-07-21 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1994-07-20 1995-01-19 1995-07-21 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1998-07-20 1999-01-19 1999-07-21 $7700.00 Window Closed / Lapsed

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