US3813686A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ambient light responsive control of brightness, contrast and color saturation
Assignee: Magnovox Co
•
Filing: 1973-04-13
•
Granted: 1974-05-28
•
Expires: 1993-04-13
Abstract
Abstract A circuit deployed in a color television receiver for varying the brightness, contrast and color saturation of a displayed picture in accordance with variations in ambient light in the vicinity of a receiver screen is disclosed comprising a light sensing means mounted near the receiver screen and having an electrical parameter which varies in accordance with variations in the light incident on the light sensing means and means responsive to those variations in the electrical parameter for varying the gains imparted to the luminance and chrominance signals in separately controlled diverse manners. In the disclosed preferred embodiment the light sensing means is a light dependent resistor such as a simple cadmium sulphide cell the resistance of which varies in response to changes in the light impinging thereon. These variations in resistance are used to control the gain of both the chrominance and the luminance amplifiers of the receiver with the luminance gain being changed with a first particular gain rate and the chrominance gain at a second particular gain rate with a given change in ambient light level. In a preferred embodiment, the luminance gain rate is approximately 50 percent greater than the chroma gain rate for a given change in ambient light, when such gains are measured in decibels.
Inventors
- 👤 E Mierzwinski
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 22:59
CPC Classifications
H; H04; H04N; H04N9/00; H04N9/64; H04N9/68; H04N5/00; H04N5/44; H04N5/57; H04N5/58
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
77 words
In a color television apparatus, a circuit for varying color display characteristics in accordance with variations in ambient light comprising: light sensing means having an electrical parameter which varies in accordance with variations in ambient light intensity incident thereon: and means responsive to variations in said electrical parameter to individually control the gains imparted to both the luminance and chroma signals of the color display to change the color display in accordance with the ambient light intensity.
Claim 2
Dependent Claim
77 words
In a color television apparatus, a circuit for varying color display characteristics in accordance with variations in ambient light comprising: light sensing means having an electrical parameter which varies in accordance with variations in ambient light intensity incident thereon: and means responsive to variations in said electrical parameter to individually control the gains imparted to both the luminance and chroma signals of the color display to change the color display in accordance with the ambient light intensity.
Claim 3
Dependent Claim
85 words
In a color picture display system having a display device comprising: means for amplifying the chroma signals, means for amplifying the luminance signals, light sensing means having an electrical parameter which varies in accordance with variations in light incident thereon, and modifying means responsive to variations in said electrical parameter for varying the gain of the chroma amplifying means in one manner and for varying the gain of the luminance amplifying means in a diverse manner from said one manner as ambient light is varied.
Claim 4
Dependent Claim
85 words
In a color picture display system having a display device comprising: means for amplifying the chroma signals, means for amplifying the luminance signals, light sensing means having an electrical parameter which varies in accordance with variations in light incident thereon, and modifying means responsive to variations in said electrical parameter for varying the gain of the chroma amplifying means in one manner and for varying the gain of the luminance amplifying means in a diverse manner from said one manner as ambient light is varied.
Claim 5
Dependent Claim
46 words
The display system of claim 2 with kinescope means having a first set of electrodes and a second set of electrodes, said chroma amplifying means being coupled to said first set of electrodes and said luminance amplifying means being coupled to said second set of electrodes.
Claim 6
Dependent Claim
32 words
The display system of claim 2 with said light sensing means being responsive to the intensity of the ambient light and said parameter varying in accordance with the intensity of ambient light.
Claim 7
Dependent Claim
37 words
The display system of claim 4 with said modifying means increasing the gain of said luminance amplifying means at a greater rate than the gain of said chroma amplifying means as said ambient light intensity is increased.
Claim 8
Dependent Claim
57 words
A color television apparatus comprising: a light sensing means having an electrical parameter which varies in accordance with variations in the ambient light intensity incident thereon, means responsive to variations in said electrical parameter to decrease chroma saturation with an increase in ambient light intensity and to increase chroma saturation with a decrease in ambient light intensIty.
Claim 9
Dependent Claim
57 words
A color television apparatus comprising: a light sensing means having an electrical parameter which varies in accordance with variations in the ambient light intensity incident thereon, means responsive to variations in said electrical parameter to decrease chroma saturation with an increase in ambient light intensity and to increase chroma saturation with a decrease in ambient light intensIty.
Claim 10
Dependent Claim
160 words
In a color television receiver: means to selectively receive a color television signal, means to amplify and detect said selected color television signal, luminance gain means to impart a gain to the luminance portion of said color television signal, chroma gain means to impart a gain to the chroma portion of said color television signal, modifying means responsive to ambient light and having a parameter that is varied as the ambient light is varied, said modifying means being coupled to said luminance gain means for modifying the gain of said luminance gain means in accordance with said parameter, said modifying means being coupled to the chroma gain means for modifying the gain of said chroma gain means in accordance with said parameter, kinescope means having color display means, combining means to combine the modified signal from said luminance gain means and the modified signal from said chroma gain means, to energize said color display means thereby forming a color image.
Claim 11
Dependent Claim
160 words
In a color television receiver: means to selectively receive a color television signal, means to amplify and detect said selected color television signal, luminance gain means to impart a gain to the luminance portion of said color television signal, chroma gain means to impart a gain to the chroma portion of said color television signal, modifying means responsive to ambient light and having a parameter that is varied as the ambient light is varied, said modifying means being coupled to said luminance gain means for modifying the gain of said luminance gain means in accordance with said parameter, said modifying means being coupled to the chroma gain means for modifying the gain of said chroma gain means in accordance with said parameter, kinescope means having color display means, combining means to combine the modified signal from said luminance gain means and the modified signal from said chroma gain means, to energize said color display means thereby forming a color image.
Claim 12
Dependent Claim
66 words
The receiver of claim 7 with said modifying means comprising a light dependent resistor means, impedance means coupling said light dependent resistor means to said transistor means to vary the conduction level of said transistor means as the impedance of said light dependent resistor means is varied, said transistor means being coupled to said chroma gain means to control the gain of said chroma gain means.
Claim 13
Dependent Claim
29 words
The receiver of claim 8 with second impedance means coupling said light dependent resistor means to said luminance gain means to control the gain of said luminance gain means.
Claim 14
Dependent Claim
18 words
The receiver of claim 9 with said second impedance means comprising a parallel combination of capacitance and resistance.
Claim 15
Dependent Claim
34 words
The receiver of claim 7 with said modifying means varying the gain of the luminance gain means at a greater rate than the gain of the chroma gain means as ambient light is varied.
Claim 16
Dependent Claim
31 words
The receiver of claim 7 with said modifying means being responsive to the intensity of ambient light and said parameter being varied as the intensity of the ambient light is varied.
Claim 17
Dependent Claim
43 words
The receiver of claim 7 with said modifying means attenuating the gain of said luminance amplifying means approximately fifty percent more than the gain of said chroma amplifying means, when the attenuation is measured in decibels, as said ambient light intensity is decreased.
Claim 18
Dependent Claim
209 words
In a color television receiver: means to selectively receive a color television signal, means to amplify and detect said selected color television signal, luminance gain means to impart a gain to the luminance portion of said color television signal, chroma gain means to impart a gain to the chroma portion of said color television signal, modifying means responsive to ambient light and having a parameter that is varied as the ambient light is varied, said modifying means being coupled to said luminance gain means for modifying the gain of said luminance gain means in accordance with said parameter, said modifying means being coupled to the chroma gain means for modifying the gain of said chroma gain means in accordance with said parameter, kinescope means having color display means, said color display means comprising multiple color display substances, said kinescope means having a first set of electrodes with an electrode for each of said color substances, said kinescope means having a second set of electrodes with an electrode for each of said color substances, means for coupling said modified luminance signal to said first set of electrodes, means for coupling said modified chroma signal to said second set of electrodes, whereby said modified luminance and modified chroma signals are combined.
Claim 19
Dependent Claim
209 words
In a color television receiver: means to selectively receive a color television signal, means to amplify and detect said selected color television signal, luminance gain means to impart a gain to the luminance portion of said color television signal, chroma gain means to impart a gain to the chroma portion of said color television signal, modifying means responsive to ambient light and having a parameter that is varied as the ambient light is varied, said modifying means being coupled to said luminance gain means for modifying the gain of said luminance gain means in accordance with said parameter, said modifying means being coupled to the chroma gain means for modifying the gain of said chroma gain means in accordance with said parameter, kinescope means having color display means, said color display means comprising multiple color display substances, said kinescope means having a first set of electrodes with an electrode for each of said color substances, said kinescope means having a second set of electrodes with an electrode for each of said color substances, means for coupling said modified luminance signal to said first set of electrodes, means for coupling said modified chroma signal to said second set of electrodes, whereby said modified luminance and modified chroma signals are combined.
References Cited (Backward Citations)
US2264172A
Cited
US2310671A
Cited
US3025345A
Cited
US3027421A
Cited
US3112424A
Cited
US3200193A
Cited
US3147341A
Cited
US3164673A
Cited
US3165582A
Cited
US3214517A
Cited
US3258532A
Cited
US3315029A
Cited
US3622696A
Cited
US3649755A
Cited
US3755619A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-05-27 | 1977-11-26 | 1978-05-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-27 | 1981-11-26 | 1982-05-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-27 | 1985-11-26 | 1986-05-28 | $7700.00 | Window Closed / Lapsed |