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Proceedings Paper

Visible light imaging sensor with A/D conversion at the pixel
Author(s): William J. Mandl
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Paper Abstract

MOSAD, provides a low power on focal pane analog to digital, A/D, process. In this approach, an oversample A/D is placed at each pixel site, with resultant benefits to response linearity and noise performance. An architecture for a visible light imaging sensor using silicon charge well detection was developed for application into video conferencing. There are a total of 76,800 A/D's on the chip. The devise is a monolithic integrated circuit that includes the sensors, A/D's and readout circuitry. A production 1.2 micron CCD/CMOS process was used in it construction. The array was designed with a 320 X 240 format with the pixels placed on 16 micron centers. There was negligible impact on the pixel area due to the A/D such that a fill factor of 67 percent was achieved with front side illumination. On chip power consumption is under 15 milliwatts. Pixels are read in the same manner as accessing the bit locations of a DRAM. As each row of pixels are accessed, they put ones or zeros on the output column that are sensed and passed onto the output buss. The A/D design is based on the patented MOSAD technology, It uses charge well switching at the pixel to convert the accumulated analog signal to digital data. Because of its high noise immunity, no pixel buffer amplifier is required, thus preserving fill factor. Another unique characteristic is the output data format which is directly compatible with Stream Vision, a patented digital display method. This format was adopted to produce a low cost all digital system from camera to display.

Paper Details

Date Published: 27 April 1999
PDF: 12 pages
Proc. SPIE 3649, Sensors, Cameras, and Systems for Scientific/Industrial Applications, (27 April 1999); doi: 10.1117/12.347062
Show Author Affiliations
William J. Mandl, Amain Electronics Co., Inc. (United States)

Published in SPIE Proceedings Vol. 3649:
Sensors, Cameras, and Systems for Scientific/Industrial Applications
Morley M. Blouke; George M. Williams Jr., Editor(s)

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