Tracking picture tube
AssigneeKoninklijke Philips Electronics N.V.
InventorAntonius Hendricus Maria Holtslag
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Abstract
The present invention relates to a tracking picture tube of the type in which comb-shaped electrodes or optical detecting means (22, 23) are used for generating a signal relative to the position of electron beams (9r, 9g, 9b) deflected onto phosphor strips (5r, 5g, 5b). The tube is characterized in that a first peripheral (uppermost) strip (5r) of said group of adjacent strips borders only finger portions (24a, 24b) of the first detecting means (22) in said pair of detecting means, and a second peripheral (lowermost) strip (5b) of said group of adjacent strips borders only finger portions (25a, 25b) of the second electrode (23) in said pair of detecting means. This configuration ensures improved tracking of the beams with respect to the centrally located phosphor strip.
Claims7
A picture tube (1) comprising
- a screen (2) with a plurality of interspersed sets of parallel strips (5r, 5g, 5b) of light-emitting material,
- at least one electron gun (4) for generating at least one electron beam (9r, 9g, 9b),
- a deflection unit (10) for deflecting said electron beams onto a group of at least three adjacent strips,
- at least one pair of comb-shaped electron-detecting means (22, 23;
- 32, 33) with a plurality of interdigitated finger portions (24, 25;
- 34, 35) extending parallel with the strips, for generating an electric signal relative to the position of said electron beams,
- characterized in that a first peripheral strip (5r) of said group of adjacent strips borders only finger portions (24a, 24b;
- 34) of the first detecting means (22;
- 32) in said pair of detecting means, and a second peripheral strip (5b) of said group of adjacent strips borders only finger portions (25a, 25b;
- 35) of the second detecting means (23;
- 33) in said pair of detecting means.
A picture tube as claimed in any one of the preceding claims, wherein the detecting means (22, 23;
- 32, 33) are conductive electrodes.
A picture tube as claimed in any one of the preceding claims, wherein the detecting means comprise light-emitting material.
Dependencies are inferred from the claim text.