Solid-state image sensing device providing a logarithmically proportional output signal
US5241575A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 9, 1992 |
| Grant date | Aug 31, 1993 |
| Priority date | — |
| Expiry date | Sep 9, 2012 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S257/901
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An image sensing device that outputs a signal logarithmically proportional to the intensity of the incident light. The image sensing device makes use of a sub-threshold current flowing between the drain and source of a MOS transistor when the gate voltage is below the threshold voltage (above which the MOS transistor is nominally conductive and below which nominally non-conductive). Since the logarithmic conversion is done in the photosensing section of a solid-state image sensing device, the output from the device is already compressed and is easily handled by a small capacity CCD. Some output systems for the image sensing device of the present invention are also described.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.