US5675391A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Contrast/brightness control circuit for television receiver
Assignee: Toshiba Corp
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Filing: 1995-03-23
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Granted: 1997-10-07
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Expires: 2015-03-23
Abstract
Abstract The invention is subjected for a television receiver which is capable of simultaneously displaying a picture signal by at least first and second picture images on a cathode ray tube and including means for generating the first and second picture signal, a superimposer for selectively supplying the first and second picture signal to the cathode ray tube, an APL detector for receiving the first and second picture signals to detect respective average picture levels of the first and second picture signals respectively thus producing first and second level detection signals, an ABL detector for generating a detection voltage responsive to a variation in an anode current of the cathode ray tube, and control means for controlling at least one of contrasts and brightnesses of the first end second picture signals by commonly operating on the first and second picture signals in response to the detection voltage from the ABL detector as well as for independently controlling at least one of contrasts and brightnesses of the first and second picture signals in response to the first and second detection signals from the APL detector.
Inventors
- 👤 Koichi Yamaguchi
- 👤 Teturou Onda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 09:47
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/44; H04N5/57; H04N5/445; H04N5/45
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
162 words
A television receiver capable of displaying a picture signal representing first and second picture images on a cathode ray tube, comprising: means for generating first and second picture signals; a superimposer for selectively supplying the first and second picture signals to the cathode ray tube; an APL detector for receiving the first and second picture signals and detecting respective average levels thereof thus producing first and second level detection signals; an ABL detector for generating a detection voltage responsive to a variation in anode current of the cathode ray tube; and control means for controlling at least one of contrasts and brightnesses of the first and second picture signals by commonly operating on the first and second picture signals in response to the detection voltage from the ABL detector, as well as for independently controlling at least one of contrasts and brightnesses of the first and second picture signals in response to the first and second detection signals from the APL detector.
Claim 2
Dependent Claim
162 words
A television receiver capable of displaying a picture signal representing first and second picture images on a cathode ray tube, comprising: means for generating first and second picture signals; a superimposer for selectively supplying the first and second picture signals to the cathode ray tube; an APL detector for receiving the first and second picture signals and detecting respective average levels thereof thus producing first and second level detection signals; an ABL detector for generating a detection voltage responsive to a variation in anode current of the cathode ray tube; and control means for controlling at least one of contrasts and brightnesses of the first and second picture signals by commonly operating on the first and second picture signals in response to the detection voltage from the ABL detector, as well as for independently controlling at least one of contrasts and brightnesses of the first and second picture signals in response to the first and second detection signals from the APL detector.
Claim 3
Dependent Claim
229 words
A television receiver capable of simultaneously displaying a picture signal representing first and second picture images on a cathode ray tube, comprising: means for generating first and second picture signals; a first APL detector for receiving the first picture signal, detecting an average picture level thereof and producing a first detection signal; a second APL detector for receiving the second picture signal, detecting an average picture level thereof and producing a second detection signal; a first picture signal processing means responsive to a first control signal for controlling the first picture signal in a least one of its contrast and brightness; a second picture signal processing means responsive to a second control signal for controlling the second picture signal in a least one of its contrast and brightness; a superimposer for selectively supplying the first and second picture signals from the first and second picture signal processing means to the cathode ray tube; an ABL detector for generating a detection voltage responsive to a variation in an anode current of the cathode ray tube; and a controller for supplying the first control signal responsive to the detection signal from the ABL detector and the first detection signal from the APL detector, as well as for supplying the second control signal responsive to the detection signal from the ABL detector and the second detection signal from the second APL detector.
Claim 4
Dependent Claim
229 words
A television receiver capable of simultaneously displaying a picture signal representing first and second picture images on a cathode ray tube, comprising: means for generating first and second picture signals; a first APL detector for receiving the first picture signal, detecting an average picture level thereof and producing a first detection signal; a second APL detector for receiving the second picture signal, detecting an average picture level thereof and producing a second detection signal; a first picture signal processing means responsive to a first control signal for controlling the first picture signal in a least one of its contrast and brightness; a second picture signal processing means responsive to a second control signal for controlling the second picture signal in a least one of its contrast and brightness; a superimposer for selectively supplying the first and second picture signals from the first and second picture signal processing means to the cathode ray tube; an ABL detector for generating a detection voltage responsive to a variation in an anode current of the cathode ray tube; and a controller for supplying the first control signal responsive to the detection signal from the ABL detector and the first detection signal from the APL detector, as well as for supplying the second control signal responsive to the detection signal from the ABL detector and the second detection signal from the second APL detector.
Claim 5
Dependent Claim
143 words
A television receiver as claimed in claim 2, wherein the controller further comprises: a differential amplifier including first and second transistors having their respective emitters coupled to each other: means for supplying the base of the first transistor with the first detection signal from the first APL detector; means for supplying the base of the second transistor with the second detection signal from the second APL detector; a current source circuit coupled in common to the emitter of the first and second transistors for controlling the current amount in response to the detection voltage from the ABL detector; means for supplying the first picture signal processing means with the first control signal as a collector output of the first transistor; and means for supplying the second picture signal processing means with the second control signal as a collector output of the second transistor.
Claim 6
Dependent Claim
204 words
A television receiver capable of simultaneously displaying first and second picture images on a cathode ray tube, comprising: means for generating first and second picture signals; a first APL detector for receiving the first picture signal, detecting an average picture level of the first picture signal and producing a first detection signal in accordance therewith; a second APL detector for receiving the second picture signal, detecting an average picture level of the second picture signal and producing a second detection signal in accordance therewith; a first picture signal processing means responsive to the first detection signal for controlling a gain of the first picture signal; a second picture signal processing means responsive to the second detection signal for controlling a gain of the second picture signal; a superimposer for selectively supplying the first and second picture signals from the first and second picture signal processing means to the cathode ray tube; an ABL detector for generating a detection signal responsive to a variation in an anode current of the cathode ray tube; and a controller for controlling at least one of a contrast and a brightness of an output picture signal from the superimposer in response to the detection signal from the ABL detector.
Claim 7
Dependent Claim
204 words
A television receiver capable of simultaneously displaying first and second picture images on a cathode ray tube, comprising: means for generating first and second picture signals; a first APL detector for receiving the first picture signal, detecting an average picture level of the first picture signal and producing a first detection signal in accordance therewith; a second APL detector for receiving the second picture signal, detecting an average picture level of the second picture signal and producing a second detection signal in accordance therewith; a first picture signal processing means responsive to the first detection signal for controlling a gain of the first picture signal; a second picture signal processing means responsive to the second detection signal for controlling a gain of the second picture signal; a superimposer for selectively supplying the first and second picture signals from the first and second picture signal processing means to the cathode ray tube; an ABL detector for generating a detection signal responsive to a variation in an anode current of the cathode ray tube; and a controller for controlling at least one of a contrast and a brightness of an output picture signal from the superimposer in response to the detection signal from the ABL detector.
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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) | 2000-10-06 | 2001-04-07 | 2001-10-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2004-10-06 | 2005-04-07 | 2005-10-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2008-10-06 | 2009-04-07 | 2009-10-07 | $7700.00 | Window Closed / Lapsed |