Circuit arrangement for producing a variable electron acceleration high voltage in an electron beam picture tube

Claim 2

A circuit arrangement for producing an electron acceleration high voltage in an electron beam picture tube comprising: a. an electron beam picture tube of the type having a phsophor layer on the screen portion thereof which produces different colors depending on the speed of the impinging electron beam, and a single cathode; b. first means connecting the anode of said picture tube to a constant d.c. potential; c. second means connected to said cathode of said picture tube for selectively applying different d.c. potentials to said cathode so as to cause different values of electron acceleration high voltage, and hence different speeds for the electrons, corresponding to said different colors within said picture tube; and d. third means connected to said cathode and responsive to the d.c. potential applied thereto for simultaneously switching the d.c. potentials applied to the grids of said picture tube.

Claim 3

The circuit arrangement defined in claim 1 wherein said means for selectively applying different d.c. potentials to said cathode comprises first switch means connected between said cathode and ground, and a series circuit including a second switch means and a d.c. high voltage source, said series circuit being connected in parallel with said first switch means.

Claim 4

The circuit arrangement defined in claim 1 wherein said anode is connected to a source of constant high d.c. voltage.

Claim 5

The circuit arrangement defined in claim 2 wherein said anode of the picture tube is connected to ground and wherein a constant d.c. high voltage source is connected in series with said first and second switch means.

Claim 6

The circuit arrangement defined in claim 1 wherein said third means includes a first transformer whose secondary winding is connected to the output of said second means connected to said cathode, said secondary winding of said first transformer furnishing the operating voltages for the grids of said picture tube; and wherein the output voltage generated in a further transformer, which also furnishes the cathode heating voltage, is applied to the primary winding of said first transformer.

Claim 7

A circuit arrangement as defined in claim 5 wherein the cathode heating voltage and the primary voltage of the said first transformer are taken from the same secondary winding of said further transformer which secondary winding is also connected to the output of said second means connected to said cathode; and wherein a high frequency generator is connected to the primary circuit of said further transformer.

Claim 8

A circuit arrangement as defined in claim 5 wherein said output of said second means is connected to the center tap of the secondary winding of said first transformer, and wherein said third means further includes means for rectifying the output voltage from said secondary winding.

Claim 9

A circuit arrangement as defined in claim 5 wherein a video amplifier for controlling the beam intensity control grid of said picture tube is connected to the output of said first transformer; and wherein said video amplifier is controlled by a photo-electric element by means of illumination intensity modulation.

Claim 10

In a circuit arrangement including an electron beam color picture tube of the type having a phosphor layer on the screen portion thereof which produces different colors depending on the speed of the impinging electron beam, and means for selectively applying different values of electron acceleration high d.c. voltage, which values correspond to the desired colors, between the cathode and the anode of the picture tube to cause different speeds for the electrons within the picture tube, the improvement wherein said means for selectively applying different values of electron acceleration high d.c. voltage includes controllable switch means connected to said cathode of said color picture tube for selectively applying different d.c. potentials, whose values selectively determine said different values of electron acceleration high d.c. voltage, to said cathode; and further comprising means responsive to said selectively applied different d.c. potentials for simultaneously switching the potentials applied to the grids of said picture tube.

Claim 11

In a circuit arrangement including an electron beam color picture tube of the type having a phosphor layer on the screen portion thereof which produces different colors depending on the speed of the impinging electron beam, and means for selectively applying different values of electron acceleration high d.c. voltage, which values correspond to the desired colors, between the cathode and the anode of the picture tube to cause different speeds for the electrons within the picture tube, the improvement wherein said means for selectively applying different values of electron acceleration high d.c. voltage includes controllable switch means connected to said cathode of said color picture tube for selectively applying different d.c. potentials, whose values selectively determine said different values of electron acceleration high d.c. voltage, to said cathode; and further comprising means responsive to said selectively applied different d.c. potentials for simultaneously switching the potentials applied to the grids of said picture tube.

Claim 12

The circuit arrangement defined in claim 1 wherein said third means includes a first transformer having a primary winding and a center tapped secondary winding with said center tap connected to said cathode, a pair of oppositely poled rectifiers, each of which is connected in series with a respective end of said secondary winding, means for applying an a.c. signal to said primary winding, and circuit means for feeding the rectified output voltages of said first transformer to the intensity control, preacceleration and focusing grids of said picture tube.

Claim 13

The circuit arrangement defined in claim 10 wherein said means for applying an a.c. signal includes a second transformer having its input connected to a high frequency a.c. generator and its output connected to said primary winding of said first transformer and to the heating filament for said cathode of said picture tube.

Claim 14

The circuit arrangement defined in claim 9 wherein said means for simultaneously switching the potentials applied to the grids includes a first transformer having a primary winding and a center tapped secondary winding with said center tap connected to said cathode, a pair of oppositely poled rectifiers, each of which is connected in series with a respective end of said secondary winding, means for applying an a.c. signal to said primary winding, and circuit means for feeding the rectified output voltages of said first transformer to the intensity control, preacceleration and focusing grids of said picture tube.

Claim 15

The circuit arrangement defined in claim 12 wherein said means for applying an a.c. signal includes a second transformer having its input connected to a high frequency a.c. generator and its output connected to said primary winding of said first transformer and to the heating filament for said cathode of said picture tube.