Color television receiver
AssigneeSony Corporation
InventorsAkira Toyama, Akio Ohkoshi, Takashi Toyama, Takahiro Yukawa, Takashi Hosono
Life of this patent
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Abstract
A control system for a beam index cathode ray tube momentarily gates or turns off all beam current at the transition from one color modulating signal to another. The resulting dip in the electron beam density, as it scans across an index phosphor stripe located between adjacent color phosphor areas, produces a substantially corresponding dip in the index signal derived from excitation of the index phosphor stripe by the electron beam. The dip in the index signal is detectable as an indication of the phase of the index signal substantially independent of differences in the amplitude of the electron beam current.
Claims17
A control system for a beam index cathode ray tube of the type which generates an index signal in response to the position of a scanning electron beam comprising:
- means responsive to said index signal for generating a plurality of sequentially repeating color gating signals, means for providing gaps between at least some adjacent ones of said color gating signals, color gate means responsive to said color gating signals for sequentially gating a corresponding plurality of color signals for modulating the intensity of said electron beam, said gaps being effective to produce corresponding dips in said index signal, and means for detecting a phase of said dips with respect to said index signal and for controlling said color gating signals in response to said phase.
A color television receiver comprising:
- a beam index cathode ray tube having a screen, adjacent sets of color phosphor areas sequentially repeating across an image area on said screen, beam forming means for forming an electron beam scannable on said screen, index signal generating means located between adjacent pairs of said color phosphor areas for generating an index signal in response to said electron beam scanning on said screen, color gating signal generating means phase controlled by said index signal for generating first, second and third sequentially repeating color gating signals spaced 120 degrees apart, means for providing gaps between at least some adjacent ones of said color gating signals, and color gate means responsive to said color gating signals for gating first, second and third color modulation signals onto said electron beam so as to modulate the intensity of the latter, said gaps producing corresponding dips in said index signal whereby phase control of said color gating signal generating means by said index signal is substantially independent of the intensity of said electron beam when scanning said pairs of color phosphor areas between which said index signal generating means are located.
In a color television receiver of the type having a beam index color cathode ray tube which contains a screen with an image area having sequentially repeating color phosphor areas thereon, index stripe means located between adjacent pairs of color phosphor areas for generating an index signal as an electron beam is scanned across said screen, a control system for the beam index color cathode ray tube which contains means responsive to said index signal for generating sequentially repeating first, second and third color gating signals, color gate means responsive to said first, second and third color gating signals for sequentially applying first, second and third color modulating signals to said electron beam for modulating the intensity of the latter;
- the improvement comprising:
- means for providing gaps between at least some of said color gating signals whereby corresponding dips are created in the intensity of said electron beam substantially in correspondence at least to its scanning over said index stripe means whereby corresponding dips in said index signal are produced.
A method of controlling a beam index color cathode ray tube comprising scanning an electron beam across an image area of said cathode ray tube, generating an index signal responsive to the passage of said electron beam over index stripes in said image area, sequentially gating first, second and third color modulating signals onto said electron beam for modulating the intensity of the latter, phase locking the sequential gating to the index signal, producing dips in the intensity of said electron beam in correspondence to the passage thereof over said index stripes whereby corresponding dips are produced in said index signal, and accuracy of said sequential gating is improved.
A color television receiver comprising:
- a beam index cathode ray tube having a screen including an image area, adjacent sets of color phosphor areas sequentially repeating across said image area of the screen, beam forming means for forming an electron beam scannable on said screen, index signal generating means for generating an index signal in response to said electron beam scanning on said screen in predetermined positional relationship to said sets of color phoshpor areas, color gating signal generating means phase controlled by said index signal for generating first, second and third sequentially repeating color gating signals spaced 120 degrees apart, means for providing gaps between at least some adjacent ones of said color gating signals, and color gate means responsive to said color gating signals for gating first, second and third color modulation signals onto said electron beam so as to modulate the intensity of the latter, said gaps producing corresponding dips in said intensity of the electron beam, said screen further including a run-in area contiguous with an edge of said image area, said index signal generating means including index stripes in said run-in area and in said image area with an omission of an index stripe in said run-in area nearest said image area producing a characteristic detectable by said gating means to preset said color gating signal generating means.
A color television receiver comprising:
- a beam index cathode ray tube having a screen including an image area and a run-in area contiguous with an edge of said image area, adjacent sets of color phosphor areas sequentially repeating across an image area on said screen, beam forming means for forming an electron beam scannable on said screen, index signal generating means for generating an index signal in response to said electron beam scanning on said screen in predetermined positional relationship to said sets of color phosphor areas, color gating signal generating means phase controlled by said index signal for generating first, second and third sequentially repeating color gating signals spaced 120 degrees apart, means for providing gaps between at least some adjacent ones of said color gating signals, color gate means responsive to said color gating signals for gating first, second and third color modulation signals onto said electrom beam so as to modulate the intensity of the latter, said gaps producing corresponding dips in said intensity of the electron beam, said index signal generating means including index stripes in said run-in area and in said image area, said index stripes in said run-in area having a normal spacing between adjacent ones thereof, and at least one adjacent pair of index stripes in said run-in area having a wide spacing therebetween exceeding said normal spacing, said gating means including a retriggerable multivibrator having a period exceeding a normal period of said index signal and being permitted to complete its cycle when the electron beam scans over said wide spacing, and means responsive to the completion of a cycle of said retriggerable multivibrator for presetting said color gating signal generating means.
Dependencies are inferred from the claim text.