CMOS active pixel with memory for imaging sensors
US6552745B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Apr 8, 1998 |
| Grant date | Apr 22, 2003 |
| Priority date | — |
| Expiry date | Apr 8, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N25/772
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An imaging apparatus and a method of capturing and storing an image in digital form within a photosensitive area of the apparatus include integrating an array of memory cells within each pixel of the photosensitive area. Preferably, the memory cells are dual port memory cells, such that write operations can be performed in a parallel manner while reading operations are performed in a serial manner. In the preferred embodiment, each array contains a sufficient number of memory cells to store two digital words representing a photo signal and a reference signal. A comparator within each pixel operating in unison with a counter and a ramp generator captures the photo signal and the reference signal in digital form. The design of the imaging apparatus allows each pixel in the photosensitive area to capture and store the signals in a parallel manner. The parallel function of the apparatus increases the electronic shutter speed, while the integrated memory array eliminates the need for an external frame buffer memory.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.