Abstract The beam index concept for color television display tubes has been known for some time, and although this color display approach is fundamentally more attractive than the commercially favored three-gun shadow mask tube, techniques for producing the indexing signal have been inadequate. According to the invention, index signals in a single-gun tube with horizontal phosphor stripes, operating in a line (color)-sequential mode, are generated by UV phosphor bars spaced uniformly along each color stripe but with different spacings for each color. As the beam scans a stripe, an optical signal is generated with a frequency corresponding to the periodicity of the phosphor index bars. The optical signal is detected with a UV detector. The amplitude of each frequency will indicate the beam size and vertical position. The index signals are fed to a signal processor which, by simple filtering, will generate error correction signals which are in turn fed to the deflection circuit to correct the beam position. The use of the optical index signal ensures isolation of the beam index signal from the video.
A beam index cathode ray display device comprising: a vacuum envelope, a cathodoluminescent screen within said envelope and made up of at least two series of alternating parallel phosphor stripes each series comprising a different color phosphor, a single electron beam forming and scanning means within said envelope adapted to scan sequentially the alternate stripes in the direction of their length, the invention characterized in that the alternate phosphor stripes additionally include a plurality of ultraviolet phosphor regions spaced equally apart on the stripes of each series but with different spacings for each series so that the beam, on scanning a given stripe, generates an optical pulse signal with a frequency characteristic of the color of the phosphor of that stripe, and characterized further by means for detecting the optical pulse signal.
Claim 2
Dependent Claim
132 words
A beam index cathode ray display device comprising: a vacuum envelope, a cathodoluminescent screen within said envelope and made up of at least two series of alternating parallel phosphor stripes each series comprising a different color phosphor, a single electron beam forming and scanning means within said envelope adapted to scan sequentially the alternate stripes in the direction of their length, the invention characterized in that the alternate phosphor stripes additionally include a plurality of ultraviolet phosphor regions spaced equally apart on the stripes of each series but with different spacings for each series so that the beam, on scanning a given stripe, generates an optical pulse signal with a frequency characteristic of the color of the phosphor of that stripe, and characterized further by means for detecting the optical pulse signal.
Claim 3
Dependent Claim
42 words
The device of claim 1 further including means for processing the optical pulse signal to generate beam position error correction signals and means for imposing these error correction signals on the electron beam forming and scanning means to correct the beam position.