CMOS image sensor with pixel level A/D conversion
US5461425A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 15, 1994 |
| Grant date | Oct 24, 1995 |
| Priority date | — |
| Expiry date | Feb 15, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH03M3/456
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An image sensor formed using a CMOS process is described herein which includes a pixel array core of phototransistors whose conductivities are related to the magnitude of light impinging upon the phototransistors. The analog signals generated by the phototransistors are converted to a serial bit stream by an A/D converter connected at the output of each phototransistor and formed in the immediate area of each phototransistor within the array core. Thus, a separate digital stream for each pixel element is output from the array core, and parasitic effects and distortion are minimized. In one embodiment, a filter circuit is connected to an output of the array core for converting the individual digital streams from each pixel element to multi-bit values corresponding to the intensity of light impinging on the phototransistor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.