Television display of data or graphics

Claim 2

A display system in which image-representative video signals are processed (10,12,13) and applied to intensity control electrodes of an image display device (15) and in which graphics information can be displayed by said device (15) in response to signals representative of such information to be displayed, characterized by switching means (31-36) which, in response to switching control signals (MONO, R,G,B) derived (27) from said signals representing said graphics information to be displayed, are operable for in one state (31,32,33 closed, 34,35,36 open) coupling said processed video signals to said control electrodes when an image represented thereby is to be displayed, and for in another state (31,32,33 open, 34,35,36 closed) instead coupling to said electrodes during graphics display intervals in a graphics display operating mode of the system, a biasing means (25) providing an intensity bias signal (V A ) representative of a desired intensity level for displayed graphics information.

Claim 3

A system according to claim 1 characterized by a video output amplifier stage (16) coupled between said switching means (31-36) and said intensity control electrodes for supplying amplified signals to said electrodes.

Claim 4

A system according to claim 2, characterized in that said switching means comprises first switching means (31,32,33) having signal and control input terminals coupled to receive said processed video signals and switching control signals (MONO) respectively, and second switching means (34,35,36) having signal and control input terminals coupled to receive said graphics bias signal (V ) and switching control signals (R,G,B) respectively, said first and second switching means having signal output terminals coupled in common to the input of said amplifier stage (16).

Claim 5

A system according to claim 1, 2 or 3 characterized in that said switching means (31-36) comprise signal transmission gates operable between conductive and nonconductive states.

Claim 7

A system according to claim 5, characterized by further switching means (252,255,257) coupled between the output side of said first-mentioned switching means (31-36) and a point of reference potential (V ) corresponding to a desired black level of a displayed image, and having a switching control input responsive to said blanking signal in said second graphics display mode for rapidly connecting said switching means output side to said reference potential at the end of graphics display intervals in said second graphics display mode.

Claim 8

A color television receiver display system including a plurality of video signal paths for conducting a plurality of color image representative video signals (R,G, B ) derived (10,12,13) from a composite television signal which can include encoded graphics information to be displayed, a kinescope (15) for displaying images derived from said video signals, and a video output amplifier stage (16) having signal inputs coupled to said paths and signal outputs coupled to respective intensity control electrodes of said kinescope, characterized by means, including graphics signal decoding means (27), for decoding said television signal to derive therefrom decoded output signals (MONO, R, G ,B) representative of said graphics information to be displayed; bias means (25) for providing a graphics intensity bias signal (V ) representative of a desired intensity level of displayed graphics information; a plurality of video signal switching means (31,32,33) each having a signal input terminal coupled to a separate one of said video signal paths, a signal output terminal coupled to a separate one of said video amplifier inputs, and a switching control input terminal; a plurality of graphics signal switching means (34,35,36) each having a signal input terminal coupled to said bias means (25), a signal output terminal coupled to a separate one of said video amplifier stage inputs, and a switching control input terminal; and control means (22) responsive to output signals from said decoding means for providing, to said switching control input terminals of said video and graphics signal switching means (31-36), switching control signals for (a) in a normal operating mode of said receiver enabling said plurality of video switching means (31-33) to conduct video signals to said video amplifier (16) and disabling said plurality of graphics switching means (34-36) to prevent conduction of said graphics bias signal to said video amplifier (16), and (b) during graphics display intervals in a graphics display operating mode of said receiver, disabling said plurality of video switching means (31-33) to prevent conduction of video signals to said video amplifier (16) and enabling said plurality of graphics switching means (34-36) to conduct said graphics bias voltage (V ) to said video amplifier (16).

Claim 9

A color television receiver display system including a plurality of video signal paths for conducting a plurality of color image representative video signals (R,G, B ) derived (10,12,13) from a composite television signal which can include encoded graphics information to be displayed, a kinescope (15) for displaying images derived from said video signals, and a video output amplifier stage (16) having signal inputs coupled to said paths and signal outputs coupled to respective intensity control electrodes of said kinescope, characterized by means, including graphics signal decoding means (27), for decoding said television signal to derive therefrom decoded output signals (MONO, R, G ,B) representative of said graphics information to be displayed; bias means (25) for providing a graphics intensity bias signal (V ) representative of a desired intensity level of displayed graphics information; a plurality of video signal switching means (31,32,33) each having a signal input terminal coupled to a separate one of said video signal paths, a signal output terminal coupled to a separate one of said video amplifier inputs, and a switching control input terminal; a plurality of graphics signal switching means (34,35,36) each having a signal input terminal coupled to said bias means (25), a signal output terminal coupled to a separate one of said video amplifier stage inputs, and a switching control input terminal; and control means (22) responsive to output signals from said decoding means for providing, to said switching control input terminals of said video and graphics signal switching means (31-36), switching control signals for (a) in a normal operating mode of said receiver enabling said plurality of video switching means (31-33) to conduct video signals to said video amplifier (16) and disabling said plurality of graphics switching means (34-36) to prevent conduction of said graphics bias signal to said video amplifier (16), and (b) during graphics display intervals in a graphics display operating mode of said receiver, disabling said plurality of video switching means (31-33) to prevent conduction of video signals to said video amplifier (16) and enabling said plurality of graphics switching means (34-36) to conduct said graphics bias voltage (V ) to said video amplifier (16).

Claim 11

A system according to claim 8 characterized in that said bias means (25) further includes means (66,70) for establishing a minimum level for said graphics intensity bias signal and means (75,76,77) for establishing a maximum level thereof.

Claim 12

A system according to claim 9 further characterized by means (64,65) coupled to said bias means (25) for controlling the magnitude of said graphics intensity bias signal (V ) in a direction to reduce the magnitude of currents in said image display device (15), in response to the magnitude of said graphics intensity bias signal when currents associated with said bias signal (V ) exceed a level otherwise sufficient to cause excessive currents in said device.