Patent EP0354518A2 successfully refreshed from Google Patents.
EP0354518A2
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EP
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Circuitry for preventing doming phenomenon in a television receiver and a preventing method thereof
Assignee: Sanyo Electric Co Ltd
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Filing: 1989-08-07
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Granted: —
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Expires: 2009-08-07
Abstract
Abstract Circuitry for preventing a doming phenomenon in a color television receiver includes circuitry (5, 6, 7, 8, 9, 10) for detecting the presence or absence of a high luminance portion not less than a predetermined area on a television receiver screen, and circuitry (11, 60, 2, 3) for slowly and gradually reducing at least one of luminance and contrast of the screen when the high luminance portion not less than a predetermined area exists on the screen. The area detecting circuitry includes a circuit (5, 6; 5′, 6′) for detecting the presence of the high luminance portion on the screen, a first charge/discharge circuit 9 for generating a signal, the level of which shifts slowly in a first direction when this high luminance potion larger than a predetermined width exists, and shifts rapidly in a second direction when it is absent, a circuit (10) for comparing an output of the charge/discharge circuit with a second reference voltage and for deciding whether the area of the high luminance portion is not less than a predetermined area, a circuit (11) for generating a control signal for gradually reducing the luminance/contrast to the presence of the high luminance portion not less than a predetermined area in response to an output of the decision circuit and for rapidly recovering the luminance/contrast to the original state in response to the absence thereof.
Inventors
- 👤 Toshikazu Okamoto
- 👤 Fukashi Inoue
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-09 13:02
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/44; H04N5/57
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
116 words
Circuitry for preventing a doming phenomenon in a television receiver for producing a video signal, said television receiver having a screen on which a picture is reproduced, said circuitry comprising: means (5, 6, 7, 8, 9, 10; 5′, 6′, 7, 8, 9, 10, 50′) responsive to a luminance signal included in said video signal for deciding whether or not a high luminance portion not less than a predetermined area exists on said screen, and means (2, 3, 11, 60) responsive to a signal for detecting the presence of the high luminance portion not less than said predetermined area from said decision means for gradually reducing at least one of the luminance and contrast of said screen.
Claim 2
Dependent Claim
116 words
Circuitry for preventing a doming phenomenon in a television receiver for producing a video signal, said television receiver having a screen on which a picture is reproduced, said circuitry comprising: means (5, 6, 7, 8, 9, 10; 5′, 6′, 7, 8, 9, 10, 50′) responsive to a luminance signal included in said video signal for deciding whether or not a high luminance portion not less than a predetermined area exists on said screen, and means (2, 3, 11, 60) responsive to a signal for detecting the presence of the high luminance portion not less than said predetermined area from said decision means for gradually reducing at least one of the luminance and contrast of said screen.
Claim 3
Dependent Claim
84 words
Circuitry for preventing a doming phenomenon in accordance with claim 1, wherein said decision means comprises: means (6: 6′) for comparing said luminance signal with a first reference voltage, means (9) responsive to an output of said comparison means for detecting the area of the high luminance portion on said screen, and means (10) for comparing an output of said area detecting means with a second reference voltage and for deciding whether or not said detected area is not less than a predetermined area.
Claim 4
Dependent Claim
84 words
Circuitry for preventing a doming phenomenon in accordance with claim 2, wherein said area detection means comprises means (Q9, R30, R31, R32, D3, C9) for shifting rapidly a voltage of the output of said comparison means in a first direction when the output of said comparison means indicates the presence of said high luminance portion, and for shifting relatively slowly the output voltage of said comparison means in a second direction when said comparison means output indicates the absence of said high luminance portion.
Claim 5
Dependent Claim
31 words
Circuitry for preventing a doming phenomenon in accordance with claim 2, wherein said area decision means comprises means (OP2) for comparing said area detection means output with the second reference voltage.
Claim 6
Dependent Claim
147 words
Circuitry for preventing a doming phenomenon in accordance with claim 1, wherein said luminance/contrast reduction means comprises means (R36, R37, R38, D4, C10) for slowly shifting a voltage of the output of said decision means in a first direction when said decision means output indicates the presence of the high luminance portion not less than said predetermined area, and for rapidly shifting the output voltage of said decision means in a second direction in response to said decision means output indicating the absence of the high luminance portion not less than said predetermined area, and means (2, 3) responsive to an output of said voltage changing means for changing at least one of the contrast and luminance of said screen, said contrast/luminance changing means gradually reducing at least one of said contrast/luminance in response to the change of said voltage shifting means output in said first direction.
Claim 7
Dependent Claim
40 words
Circuitry for preventing a doming phenomenon in accordance with claim 1, wherein said decision means is adapted to have sensitivity in detection of the high luminance portion enhanced at the periphery of said screen rather than at the center thereof.
Claim 8
Dependent Claim
91 words
Circuitry for preventing a doming phenomenon in accordance with claim 2, further comprising means (8) for generating said first reference voltage, said first reference voltage generating means being responsive to a signal which changes at a horizontal scanning period of said screen for generating as said first reference voltage a signal the output level of which changes at said horizontal scanning period, thereby decreasing a reference level of said comparison means at the periphery of said screen and improving the sensitivity in detection of the high luminance portion at said periphery.
Claim 9
Dependent Claim
116 words
Circuitry for preventing a doming phenomenon in accordance with claim 2, further comprising means (7, 8) for generating said first reference voltage, wherein said reference voltage generating means comprises first means (8) responsive to a signal applied at a horizontal scanning period of said screen for generating a voltage signal the level of which changes at said horizontal scanning period, second means (7) responsive to a signal which changes in a vertical scanning period of said screen for generating a voltage signal the output voltage level of which changes at said vertical scanning period, and third means (40) for adding the voltage signals from said first and second means and for generating said first reference voltage.
Claim 10
Dependent Claim
37 words
Circuitry for preventing a doming phenomenon in accordance with claim 1, wherein said decision means has an input stage comprising low pass means for receiving said luminance signal and for passing only predetermined low frequency components thereof.
Claim 11
Dependent Claim
155 words
Circuitry for preventing a doming phenomenon in a television receiver for reproducing a video signal, said television receiver comprising a screen on which said video signal is reproduced, a circuit for controlling luminance of said screen, and a circuitry for controlling contrast of said screen, said circuitry comprising: means (5, 6, 7, 8, 9, 10; 5′, 6′, 7, 8, 9, 10) responsive to a luminance signal included in said video signal for deciding whether or not a high luminance portion not less than a predetermined area exists on said screen; and means (11) responsive to a signal for detecting the presence of the high luminance portion not less than said predetermined area from said decision means for generating a control signal for gradually reducing at least one of the luminance and contrast of said screen and for applying said control signal to at least one of said luminance control circuit and said contrast control circuit.
Claim 12
Dependent Claim
155 words
Circuitry for preventing a doming phenomenon in a television receiver for reproducing a video signal, said television receiver comprising a screen on which said video signal is reproduced, a circuit for controlling luminance of said screen, and a circuitry for controlling contrast of said screen, said circuitry comprising: means (5, 6, 7, 8, 9, 10; 5′, 6′, 7, 8, 9, 10) responsive to a luminance signal included in said video signal for deciding whether or not a high luminance portion not less than a predetermined area exists on said screen; and means (11) responsive to a signal for detecting the presence of the high luminance portion not less than said predetermined area from said decision means for generating a control signal for gradually reducing at least one of the luminance and contrast of said screen and for applying said control signal to at least one of said luminance control circuit and said contrast control circuit.
Claim 13
Dependent Claim
84 words
Circuitry for preventing a doming phenomenon in accordance with claim 10, wherein said control means comprises means (6; 6′) for comparing said luminance signal with a first reference voltage, means (9) responsive to the output of said comparison means for detecting the area of the high luminance portion on said screen, and means (10) for comparing the output of said area detection means with a second reference voltage and for deciding whether or not said detected area is not less than a predetermined area.
Claim 14
Dependent Claim
71 words
Circuitry for preventing a doming phenomenon in accordance with claim 11, wherein said area detection means comprises means for shifting rapidly a voltage of said comparison means output in a first direction when said comparison means output indicates the presence of said high luminance portion, and for shifting relatively slowly the output voltage thereof in a second direction when said comparison means output indicates the absence of said high luminance portion.
Claim 15
Dependent Claim
30 words
Circuitry for preventing a doming phenomenon in accordance with claim 11, wherein said decision means comprises means (OP2) for comparing said area detection means output with a second reference voltage.
Claim 16
Dependent Claim
83 words
Circuitry for preventing a doming phenomenon in accordance with claim 10, wherein said control signal generating means comprises means for shifting slowly an output voltage of said decision means in a first direction when said decision means output indicates that said high luminance portion is not less than a predetermined area, and for shifting rapidly the output voltage thereof in a second direction responsive to said decision means output indicating the absence of the high luminance portion not less than said predetermined area.
Claim 17
Dependent Claim
52 words
Circuitry for preventing a doming phenomenon in accordance with claim 11, wherein a first reference voltage applied to said comparison means has its level decreased in an absolute value at the periphery of said screen, thereby enhancing the sensitivity in detection of the high luminance portion at the periphery of said screen.
Claim 18
Independent Claim
96 words
A method of preventing a doming phenomenon in a television receiver for reproducing a video signal, said television receiver having a screen on which said video signal is reproduced, said method comprising the steps of: deciding whether or not a high luminance portion not less than a predetermined area exists on said screen in response to a luminance signal included in said video signal; and reducing gradually at least one of contrast and luminance of said screen in response to detection of the high luminance portion not less than said predetermined area in said decision step.
Claim 19
Independent Claim
96 words
A method of preventing a doming phenomenon in a television receiver for reproducing a video signal, said television receiver having a screen on which said video signal is reproduced, said method comprising the steps of: deciding whether or not a high luminance portion not less than a predetermined area exists on said screen in response to a luminance signal included in said video signal; and reducing gradually at least one of contrast and luminance of said screen in response to detection of the high luminance portion not less than said predetermined area in said decision step.
Claim 20
Dependent Claim
120 words
A method of preventing a doming phenomenon in accordance with claim 16, wherein said decision step comprises the steps of: comparing said high luminance signal with a first reference voltage, thereby detecting the presence or absence of the high luminance portion on said screen, generating a first control signal the signal level of which shifting rapidly in a first direction in response to the detection of the luminance portion in said comparison/detection step and shifting slowly in response to the detection of the absence of said luminance portion, and comparing said first control signal with a second reference voltage and deciding whether or not the high luminance portion on said screen is not less in area than a predetermined area.
Claim 21
Dependent Claim
97 words
A method of preventing a doming phenomenon n accordance with claim 16, wherein said reduction step comprises the step of reducing gradually at least one of the luminance and contrast of said screen in response to the detection of the presence of the high luminance portion not less than said predetermined area, and generating a second control signal for rapidly recovering said at least one of the reduced contrast and luminance of said screen to an original state in response to the detection of the absence of the high luminance portion not less than said predetermined area.
Claim 22
Dependent Claim
130 words
A doming-free television receiver having a screen on which a video signal is reproduced, comprising: means (5, 6; 5′, 6′) responsive to a luminance signal included in said video signal for detecting the presence of a high luminance portion on said screen; means (9) responsive to an output of said detection means for detecting the area of said detected high luminance portion; means (10) responsive to an output of said area detection means for deciding whether or not the area of the detected high luminance portion is not less than a predetermined value; and means (11, 2, 3) responsive to said decision means indicating that said high luminance portion is not less than a predetermined area for gradually reducing at least one of the luminance and contrast of said screen.
Claim 23
Dependent Claim
130 words
A doming-free television receiver having a screen on which a video signal is reproduced, comprising: means (5, 6; 5′, 6′) responsive to a luminance signal included in said video signal for detecting the presence of a high luminance portion on said screen; means (9) responsive to an output of said detection means for detecting the area of said detected high luminance portion; means (10) responsive to an output of said area detection means for deciding whether or not the area of the detected high luminance portion is not less than a predetermined value; and means (11, 2, 3) responsive to said decision means indicating that said high luminance portion is not less than a predetermined area for gradually reducing at least one of the luminance and contrast of said screen.
References Cited (Backward Citations)
No citation records indexed.
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