Color television camera provided with one pick-up tube and a color filter with means for converting a sequential output to a simultaneous output

Claim 2

A color television camera comprising one pick-up tube including a photo-sensitive target plate, a video output, and an electron gun for producing an electron beam directed towards said target plate; a color filter positioned in an input light path to said target plate, said filter having a time variable transmission color; means for causing said beam to scan the target plate in the form of a line scan raster having a given field frequency, means for varying the transmission color in synchronism with said field frequency or an integral submultiple thereof; a converter having a plurality of outputs and an input coupled to said video output of the pick-up tube for converting video signals generated by the pick-up tube when the filter has successive transmission colors into substantially simultaneously occurring video signals at said plurality of outputs of the converter; and a generator having an output coupled to the electron gun for periodically interrupting the electron beam during each line scan period, said interrupted portions of each line scan on the target plate being displaced in the line direction relative to the interrupted portions of a previous line scan over substantially the same part of the target plate.

Claim 3

A camera as claimed in claim 1 where said generator supplies a substantially square-wave output signal which is successively phase shifted by substantially 120* in accordance with successive colors of the filter.

Claim 4

A camera as claimed in claim 2 wherein the generator comprises an oscillator having an output, a frequency divider having an input coupled to said oscillator output and an output, a phase shifter having an input coupled to said divider output and three outputs, a first change-over switch having three inputs coupled to said divider outputs respectively and an output coupled to the electron gun of the pick-up tube, and means for changing over said first switch at field or frame frequency so that said first switch output is coupled to a different one of the first switch inputs during each field or frame of three successive fields or frames respectively.

Claim 5

A camera as claimed in claim 2 wherein said generator output signal has a mark-to-space ratio of substantially 1:1, whereby said camera can be used in a television having three primary colors.

Claim 6

A camera as claimed in claim 2 wherein said output signal has a mark-to-space ratio of substantially 2:1 for cutting off the electron gun for substantially one third of each period of the square-wave signal, whereby said camera can be used in a television system having two primary colors.

Claim 7

A camera as claimed in claim 1 further comprising an on-off switch having a control input coupled to said generator and a resistor coupled to said on-off switch and a voltage source, the common point of the resistor and said on-off switch being coupled to a cathode of the electron gun.

Claim 8

A camera as claimed in claim 1 wherein the generator comprises an oscillator having an output; said converter comprising a second change-over switch having a control input coupled to said oscillator output, an input coupled to said video output of the pick-up tube, and a plurality Of outputs; said converter having a plurality of signal channels coupled to said second switch outputs respectively and a plurality of outputs coupled to said channels respectively; at least one of said signal channels including a superimposition stage having a first input coupled to one of said channels, a second input coupled to another of said signal channels, and an output coupled to a converter output.

Claim 9

A camera as claimed in claim 7 wherein said generator supplies a substantially square wave output signal having a mark-to-space ratio of substantially 1:1 which is successively phase shifted by substantially 120* in accordance with successive colors of the filter, said second change-over switch comprising a three-position output change-over switch, said channels being three in number, said second switch three outputs being respectively coupled to said three signal channels, two of said channels respectively including first and second superimposition stages having outputs, said channels respectively comprising ganged third, fourth, and fifth switches each having a pole and three outputs, the outputs of the two superimposition stages and the remaining signal channel being coupled to the poles of third, fourth and fifth switches respectively, first corresponding outputs of said third, fourth, and fifth switches being coupled to first, second and third converter outputs respectively, second corresponding outputs thereof being coupled to the second, third and first converter outputs respectively, and third corresponding outputs thereof being coupled to the third, first and second converter outputs respectively, and means for changing over each of said poles of said third, fourth, and fifth switches from one output position to the next at said field or frame frequency.

Claim 10

A camera as claimed in claim 7 wherein each of said signal channels includes a lowpass filter, said camera including a luminance signal channel having a highpass filter having an input coupled to an output of said second change-over switch and an output, said camera further comprising a plurality of superimposition stages each of said stages having a first input coupled to said highpass filter output and a second input coupled to said outputs of said converter respectively.

Claim 11

A camera as claimed in claim 7 wherein said generator supplies a substantially square wave output signal having a mark-to-space ratio of substantially 1:1 and which is successively phase shifted by substantially 120* in accordance with successive colors of the filter, said second change-over switch comprises a triple section switch each section having three outputs, said channels being nine in number coupled to said second switch outputs respectively, the superimposition stage comprising a plurality of controllable current sources, and at least one common load coupled to a group of said current sources.

Claim 12

A camera as claimed in claim 10 wherein the generator comprises an oscillator having an output, a frequency divider having an input coupled to said oscillator output an an output, a phase shifter having an input coupled to said divider output and three outputs, a first change-over switch having three inputs coupled to said divider outputs respectively and an output coupled to said electron gun, means for changing over said switch at a field or frame frequency so that said switch output is coupled to a different one of the switch inputs during each field or frame of three successive fields or frames, a second phase shifter having an input coupled to said oscillator output and a succession of six outputs each for supplying a signal phase-shifted by substantially 60* relative to the previous output, said converter comprising gates each having first and second inputs and an output, six of said first gate inputs being coupled to said six second phase shifter outputs, the first, third and fifth phase shifter outputs being coupled to two gates each, a third change-over switch having an inPut coupled to said first switch output and three outputs, groups of three second inputs of said nine gates each being coupled to a different output of said third change-over switch output, said outputs of the nine gates being part of said triple three-position change-over switch.

Claim 13

A camera as claimed in claim 1 wherein the converter and the generator comprise a single integrated circuit.