Method and apparatus for providing offset for light detector
US5352884A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 14, 1993 |
| Grant date | Oct 4, 1994 |
| Priority date | — |
| Expiry date | Apr 14, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05G1/60
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The invention provides a solid state light imager or x-ray detector including an array of rows and columns of elements, each element including a photo diode, which converts photons to an electrical signal, and a transistor. Each photo diode has a capacitance associated with it. The cathode of the photo diode in each element is connected to the source of the transistor in the element. The amount of charge removed from each photo diode, after exposure to light, is used to create an image. The imager is capable of accurate measurement of charge removed from the photo diodes after the array has been exposed to light, using unipolar measuring circuitry, in spite of charge retention by the transistors and a problem caused by the combination of changes in row voltage and parasitic row to column capacitance.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.