Sony Corporation

Takahiro Yukawa

Akio Ohkoshi

Takashi Hosono

Takashi Toyama

Akira Tooyama

Takashi Tooyama

Akira Toyama

Minoru Ohzeki

Hideo Kusama

Koji Kanbayashi

Osamu Takeuchi

Described is a beam index type color cathode ray tube in which at least one of tricolor phosphor stripes, that is the red, blue and green stripes, is different in width from the other color phosphor stripes, and m index stripes are associated with n sets or triplets of the color phosphor stripes. The widthwise center-to-center distance between the adjoining color phosphor stripes is set to a constant value. Each index stripe is of a width lesser than the width of the guard band provided between adjoining ones of the color phosphor stripes, and is provided at the widthwise center of the associated guard band. The arrangement provides index signals of sufficient intensity, while assuring a positive color switching.

Beam index type color cathode ray tube

An improved current dependent type color cathode ray tube which utilizes a color phosphor screen which has at least two phosphors that have current density versus brightness characteristics which differ from each other and which emit light of different colors and including an electron gun which emits an electron beam which impinges on the color phosphor screen and wherein the current density of the electron beam of the gun varies in response to color signals so as to cause the emission of the desired colors to produce a color image and wherein the focusing voltage of the electron gun is varied so that the just focussing state occurs at the highest drive current within the drive current range and the focal length associated with the focussing voltage at the just focussing state is displaced by more than 5% from the focal length represented by the lowest drive current.

Current dependent type color cathode ray tube

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.

Color television receiver

A beam index color cathode ray tube has index stripes spaced apart across a run-in area of the screen which have a pitch substantially equal to the pitch of index stripes in an image area, and a predetermined number of the index stripes in the run-in area are counted as an electron beam scans them to preset color control circuits to a predetermined condition at the commencement of scanning of the image area. A characteristic of the signal resulting from scanning of the index stripes may be used to begin the counting thereof from a specific one of the index stripes in the run-in area other than the first one encountered by the electron beam.

Beam index color cathode ray tube

A beam index color cathode ray tube has index stripes spaced apart across a run-in area of the screen and which have a pitch substantially equal to the pitch of index stripes in an image area. A plurality of the index stripes in the run-in area generate an index signal as an electron beam scans them. An index stripe is omitted from the portion of the run-in area nearest the boundary with the image area to provide a characteristic to the index signal which permits generation of a trigger signal to preset color control circuits to a known condition as the electron beam enters the image area. A gating circuit blocks trigger signals which may be generated during scanning of the image area.

Growing community of inventors

Tokyo, Japan

Takahiro Yukawa