Photodetector array interface circuit

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG.
1 of the drawing shows a stationary faceplate panel 10 which is oriented with its seal end 11 up and has a striped matrix 12 that extends into and out of the plane of FIG.
1.
Alternatively, a dot matrix panel can be used with the present system.
In order to achieve the desired inspection time, the panel 10 is illuminated by five stationary light sources or irradiating means located, respectively, at the four corners of the panel 10 and the center thereof.
These locations are called camera positions 0 to 4, respectively.
In FIG.
1, two corner sources 13 and 14 are directly behind the sources 15 and 16.
A center source 17 is between and behind sources 13 and 14.
Since the camera circuitry is identical for all five camera positions, only the circuitry associated with the source 15 is shown and described.
Light from the source 15 passes through the transparent spaces of the panel 10 to a focusing lens 18 in a camera which focuses the light onto a rotatable mirror 20 as a light/shadow image of that area of the panel 10.
It is reflected by the mirror 20 to a stationary mirror 22 and then towards a receiving means or linear photodiode array 24 disposed in the camera.
The photodiode array 24 can be an H-series model 1728 photodiode array manufactured by EG&G Reticon and, as such, has 1728 pixels (light-detecting diodes) which are individually responsive to light energy.
After the photodidoe array 24 scans the first line across the reflected image, the mirror 20 is then rotated slightly about an axis which is parallel to the plane of the paper, shown as dotted line 21, and another line is scanned across the array 24.
This action continues until a large number of lines, such as two hundred, have been scanned across the photodiode array 24.
Scanning in a direction transverse to the matrix lines is done by an ARRAY PROCESSING circuit 26 which sequentially reads out each of the 1728 diodes of the array 24 under the control of a pixel oscillator signal (OSC) on line 42 and START signal on line 44 from a CONTROL AND QUANTIZER circuit 28