Automatic intensity control for picture tube display systems

Claim 2

Apparatus for stabilizing the intensity of the image on a picture tube screen of an area which partiAlly includes an intensity reference source, wherein the area is scanned by a scanning device and the image thereof is displayed on the picture tube screen, comprising: means for continuously monitoring the image of the intensity reference source displayed on the picture tube screen, said means comprising a bundle of light transmitting optical elements having opposite ends, one end of said bundle being disposed at that part of the picture tube screen whereat the image of the intensity reference source is displayed, a photosensing element, the other end of said bundle being optically coupled to the photosensing element whereby light from said part of said picture tube screen whereat the image of the intensity reference source is displayed radiates said photosensing element through said bundle thereby generating a signal, and electronic means responsive to said signal for controlling the intensity of said image of said area displayed on said picture tube screen.

Claim 3

The invention of claim 1 wherein said electronic means comprise a circuit having an input terminal, an input capacitor connected to said input terminal, a first amplifier having first and second input terminals and an output terminal, said first input terminal being connected to receive a voltage on said capacitor, said second input and said output terminals being connected by a feedback line, a second amplifier having first and second input terminals and an output terminal, said first amplifier output terminal being connected to said first input terminal of said second amplifier, said second input terminal and said output terminal of said second amplifier being connected by a resistive feedback circuit, a voltage divider connected to said second amplifier output terminal, and a circuit output terminal connected to said voltage divider.

Claim 4

The invention of claim 2 further comprising a galvanometer connected to said circuit output terminal.

Claim 5

The invention of claim 1 wherein said electronic means comprise a circuit having a circuit input terminal, a voltage comparator having first and second input terminals, an output terminal and at least two additional terminals thereon, said first voltage comparator input terminal being connected to said circuit input terminal, a resistor connected in a feedback path between said two additional voltage comparator terminals, a capacitor, said voltage comparator second input terminal being connected to said capacitor, a voltage follower having first and second input terminals and an output terminal, said voltage follower first input terminal being connected to said capacitor, said second input terminal and said output terminal of said voltage follower being connected by a feedback circuit, a voltage divider connected to said output terminal of said voltage follower, and a circuit output terminal connected to said voltage divider.

Claim 6

The invention of claim 4 further comprising a galvanometer connected to said circuit output terminal.

Claim 7

The apparatus recited in claim 1 wherein said bundle is disposed with respect to the picture tube screen in a manner such as to minimize obstruction of the part of the picture tube screen upon which the image of the area being scanned is being displayed.

Claim 8

The apparatus of claim 6 wherein said bundle has an angular bend therein adjacent to the picture tube screen.

Claim 9

An automatic display intensity control for stabilizing the intensity of an image displayed on a picture tube screen in a thermographic machine comprising: a. IR sensing means for scanning a surface to produce an image of the IR radiant energy pattern emitted by such surface; b. IR detector means disposed adjacent said scanning means for sensing said IR radiant energy pattern emitted by said surface, and for generating an intensity control signal in response to the sensed radiations; c. bias control means for controlling the magnitude of said control image of the scanned surface; d. a picture tube having a display screeN for displaying an image of the scanned surface; e. electronic means connected between said detector and said picture tube for controlling the intensity of the image displayed on said screen with said intensity control signal; f. a photosensing element; g. a reference source on said screen; h. fiber optic light bundle means operatively disposed between said screen and said photosensing element for conveying light from the reference source on said screen to said photosensing element so that a reference signal is generated by said photosensing element; and, i. circuit means connected between said photosensing element and said bias control means for receiving the reference signal from the photosensing element and generating a bias control signal to automatically maintain the intensity of the displayed image at a predetermined level.

Claim 10

An automatic display intensity control for stabilizing the intensity of an image displayed on a picture tube screen in a thermographic machine comprising: a. IR sensing means for scanning a surface to produce an image of the IR radiant energy pattern emitted by such surface; b. IR detector means disposed adjacent said scanning means for sensing said IR radiant energy pattern emitted by said surface, and for generating an intensity control signal in response to the sensed radiations; c. bias control means for controlling the magnitude of said control image of the scanned surface; d. a picture tube having a display screeN for displaying an image of the scanned surface; e. electronic means connected between said detector and said picture tube for controlling the intensity of the image displayed on said screen with said intensity control signal; f. a photosensing element; g. a reference source on said screen; h. fiber optic light bundle means operatively disposed between said screen and said photosensing element for conveying light from the reference source on said screen to said photosensing element so that a reference signal is generated by said photosensing element; and, i. circuit means connected between said photosensing element and said bias control means for receiving the reference signal from the photosensing element and generating a bias control signal to automatically maintain the intensity of the displayed image at a predetermined level.

Claim 11

The invention of claim 8 wherein said fiber optic light bundle means has an angular bend therein adjacent to the picture tube.

Claim 12

The invention of claim 8 further comprising a reference temperature source disposed adjacent to the scanned surface whereby said temperature source will appear on said display screen, and wherein the one end of the light bundle is disposed against the screen within the area where the reference temperature source is displayed.

Claim 13

The invention of claim 8 wherein said electronic means comprises a circuit having a circuit input terminal, an input capacitor connected to said input terminal, a first amplifier having first and second input terminals and an output terminal, said first input terminal being connected to receive a voltage on said capacitor, said second input terminal and said output terminal being connected by a feedback circuit, a second amplifier having first and second input terminals and an output terminal, said first amplifier output terminal being connected to said first input terminal of said second amplifier, said second input terminal and said output terminal of said second amplifier being connected by a resistive feedback circuit, a voltage divider connected to said second amplifier output terminal, and a circuit output terminal connected to said voltage divider.

Claim 14

The invention of claim 8 wherein said electronic means comprise a circuit having a circuit input terminal, a voltage comparator having first and second input terminals, an output terminal and at least two additional terminals thereon, said first voltage comparator input terminal being connected to said circuit input terminal, a resistance feedback circuit connected between said two additional voltage comparator terminals, a capacitor, said voltage comparator second input terminal being connected to said capacitor, a voltage follower having first and second input terminals and an output terminal, said voltage follower first input terminal being connected to said capacitor, said voltage follower second input terminal and said voltage follower output terminal being connected by a feedback circuit, a voltage divider connected to said voltage follower output terminal, and a circuit output terminal connected to said voltage divider.

Claim 15

The invention of claim 12 further comprising a galvanometer connected to said circuit output terminal.

Claim 16

The invention of claim 12 wherein said photosensing element is a photoconductor and the photoconductor is connected in a circuit that is common to said circuit input terminal.

Claim 17

The invention of claim 8 wherein said electronic means comprise a circuit havingan input terminal, a voltage comparator having one input thereof connected to said input terminal, a resistor connected in a feedback path between two terminals of said voltage divider, a capacitor, another input of said voltage comparator connected to said capacitor, a voltage follower having a first input connected to receive a voltage on said capacitor, a feedback connecting the voltage follower output terminal to a second voltage follower input, a voltage divider connected to said voltage follower outPut terminal, and a circuit output terminal connected to said voltage divider.

Claim 18

The invention of claim 15 further comprising a galvanometer connected to said circuit output terminal.

Claim 19

The invention of claim 15 wherein said photosensing element is a photoconductor and the photoconductor is connected in a circuit that is common to said circuit input terminal.