Tracking picture tube
AssigneeKoninklijke Philips Electronics N.V.
InventorsHendrikus Bernardus Van Den Brink, Hans-Helmut Bechtel, Marcellinus Petrus Carolus Michael Krijn
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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 (12, 13) are used for generating a signal related to the position of an electron beam with respect to the strips (5). The tube is characterized in that the deflection unit is arranged to deflect the beams (21r, 21g, 21b) onto selected strips (22r, 22g, 22b) having coincident sides which neighbour finger portions (14, 15) of the same electrode (12, 13), and the selected strips (22r, 22g, 22b), excited by the electron beams, are separated by at least one unexcited strip, respectively.
Claims12
A picture tube (1) comprising
- a screen (2) with a plurality of interspersed sets of parallel strips (5a, 5b, 5c) of light-emitting material, each set emitting light of a specific color when hit by electrons,
- a plurality of electron guns (4), each adapted to generate an electron beam (9) associated with the strips in one of said sets of strips,
- a deflection unit (10) for deflecting each electron beam onto one of the strips in the corresponding set of strips, thereby exciting this strip to emit light, and
- at least one pair of comb-shaped electron-detecting means (12, 13) having a plurality of interdigitated finger portions (14, 15) extending parallel with the strips (5), for generating a signal (18) relative to the position of an electron beam (9) with respect to the strips (5),
- characterized in that the deflection unit (10) is arranged to deflect the beams onto selected strips (22r, 22g, 22b) having coincident sides which neighbour finger portions (14, 15) of the same detecting means (12, 13), said selected strips (22r, 22g, 22b), excited by the electron beams, being separated by at least one unexcited strip, respectively.
A picture tube as claimed in any one of the preceding claims, wherein said picture tube has three electron guns (4).
A picture tube as claimed in any one of the preceding claims, further comprising means (31) for generating a plurality of time-shifted, color-specific video signals, which are supplied to the electron guns (4).
A picture tube as claimed in any one of the preceding claims, wherein signals from said detecting means (12, 13) are used in two separate feedback control arrangements,
- a first control arrangement (36, 10) being adapted to track and control the plurality of beams (9) simultaneously, and
- a second control arrangement (40, 42, 44, 46) being adapted to track and control the position of individual beams (9),
- said first control arrangement having a higher error update frequency than said second control arrangement.
A picture tube as claimed in any one of the preceding claims, wherein the detecting means are conductive electrodes (12, 13).
A picture tube as claimed in any one of the preceding claims, wherein the detecting means are made of light-emitting material.
Dependencies are inferred from the claim text.