Imaging devices comprising photodetector elements
US4845540A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 15, 1986 |
| Grant date | Jul 4, 1989 |
| Priority date | — |
| Expiry date | Sep 15, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10F39/186
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In an imaging device, photocurrent generated by detector elements (1), e.g. cadmium mercury telluride photodiodes, may be integrated in resettable capacitors (2), and an output signal (S) may be derived by reading the potential of the capacitor (2) at the end of its integration period, e.g. using a source-follower MOST (3). In accordance with the invention first and second capacitors (2a and 2b) are switchably coupled in alternate parallel arms between each detector element (1) and the voltage-reading means (3), by means of an arrangement of input gates (8a and 8b) and output gates (9a and 9b). Since one of the first and second capacitors (2a or 2b) can be coupled to the detector element (1) while the other (2b or 2a) is coupled to the voltage-reading means (3), each detector element (1) can be switched from one to the other so as to be operated the whole time for photodetection without its signal being lost (i.e. not integrated) when reading the previous output signal from that detector element (1). This is particularly useful for coupling a row of storage capacitors via a 2-d switching array to a 2-d array of infrared detector elements (1). A similar arrangement of alternately-sw…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.