Imaging devices comprising photovoltaic detector elements
US4833515A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 15, 1986 |
| Grant date | May 23, 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 photovoltaic detector elements (1), e.g. cadmium mercury telluride photodiodes, is integrated in resettable capacitors (2), and an output signal (S) is 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, blooming-protection means (11,48,12) is coupled to each capacitor (2) to inhibit forward-biasing of the detector elements (1) and inversion of the capacitor potential when the capacitor (2) becomes fully discharged by excessive photocurrent. The blooming-protection means comprises a further gate (11) which has substantially the same threshold voltage as the injection gate (10) via which the photocurrent is injected into the capacitor (2). The further gate (11) which is connected at substantially the same control potential as the injection gate (10), is most conveniently formed together with the injection gate (10) as alternate integral parts of a common gate stripe (37) extending at one side of the capacitors (2). When a capacitor (2) becomes fully discharged, the further gate (11) couples it to a source (12) which supplies…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.