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Self Scanning Light Sensitive Integrated Array

IP.com Disclosure Number: IPCOM000081476D
Original Publication Date: 1974-Jun-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Debord, P: AUTHOR [+2]

Abstract

In self-scanning light-sensitive integrated arrays, the reading of light-sensitive diodes DI is ensured through a video line. Since the energy consumption of these light-sensitive diodes is low, the reading signal appearing on the video line is very sensitive to noise. Therefore, it is important to make the signal-to-noise ratio as large as possible by eliminating the noise appearing on the video line, in particular the noise issued from control circuits TD of the light-sensitive diodes.

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Self Scanning Light Sensitive Integrated Array

In self-scanning light-sensitive integrated arrays, the reading of light-sensitive diodes DI is ensured through a video line.

Since the energy consumption of these light-sensitive diodes is low, the reading signal appearing on the video line is very sensitive to noise. Therefore, it is important to make the signal-to-noise ratio as large as possible by eliminating the noise appearing on the video line, in particular the noise issued from control circuits TD of the light-sensitive diodes.

Light-sensitive diodes DI are read consecutively through a shift register, including a number of cells (SRC) equal to the number of diodes DI to be read. Each cell controls the turning "ON" of a transistor TD corresponding to a diode DI. The cells receive clock pulses phi 1 and phi 2 which are complementary and have the same rise and fall time. To eliminate the noise, it is necessary that, on one hand, TD be ON only for the duration of the clock pulse of the corresponding cell and not for the duration of the whole clock cycle phi 1 and phi 2 and, on the other hand, point A remains at a potential as steady as possible when the cell is not selected.

To read the light-sensitive diodes, "data in" line is set to a high level. In this case, TA is preconditioned to turn on and TB is switched off. When phi 1 comes up, TA is conducting, node A is set to a high level and TD turns ON for the reading of DI. Coupling capacitance CC works as volta...