Time domain sensing technique and system architecture for image sensor
US6642503B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 13, 2002 |
| Grant date | Nov 4, 2003 |
| Priority date | — |
| Expiry date | Jun 13, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10F39/18
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A photodiode sensor (25) has a photodiode (30) with an associated capacitance (34), which may be a parasitic capacitance of the photodiode (30). A switch (36) is provided for charging the capacitance (34) to a predetermined reset voltage (Vreset), such that when light impinges upon the photodiode (30), the voltage on the capacitance (34) discharges in a time proportional to an intensity of the light. A circuit (42) is also provided for measuring the time for the capacitance (34) to discharge to a predetermined threshold value (33), which may be a function of time. The voltage on the output (38) of the comparator (28) may be sampled, with the sampling period also being variable as a function of time. The image may be reconstructed from time data indicating the relative times that discharge voltage of the pixels in an array cross the reference voltage (33).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.