Copyright © Philip M. Parker, INSEAD. Terms of Use.
| Year | Description |
| 1999 | Invention patented by Liang-Gee Chen and Shyh-Yih Ma on April 21th, 1999. Abstract: A CMOS active pixel sensor with motion detection includes a photo diode, a reset switch, two sample and hold circuits, and two readout circuits. Each sample and hold circuit includes a MOS switch and a capacitor. The readout circuit includes a source follower and a row select switch. The two sample and hold circuits can store current frame pixel data as well as previous frame pixel data, and these two image data can be read out by the two readout circuits. Therefore, the frame difference can be directly obtained in differential mode. This CMOS active pixel sensor can be used in single chip camera systems with motion detection and video compression functions. Furthermore, because of the low supply voltage consideration in the pixel circuit, this CMOS active pixel sensor is suitable for low power applications. |
| 1999 | Invention patented by Il-Young Sohn on May 26th, 1999. Abstract: The present invention relates to a CMOS active pixel sensor which includes a compensation circuit capable of compensating a lowered pixel voltage output due to leakage current of a photodiode. The CMOS active pixel sensor having a light sensing unit for generating an output voltage when light is incident thereupon, the sensing unit having an amount of leakage current before the incidence of light. A reset unit resets the output voltage of the light sensing unit to an initial reset voltage in response to a reset signal. A sense transistor has a source, a drain coupled to a power source voltage, and a gate coupled to the output of the light sensing unit. A select transistor has a drain connected to a source of the sense transistor, and provides the voltage of the sense transistor to a bit line, in response to a select signal. A compensation unit supplies a voltage corresponding to the output voltage of the light sensing unit lowered by the leakage current. |
| Source: selected by the editor from original sources. | |
Copyright © Philip M. Parker, INSEAD. Terms of Use.
