US Patent 7738014 Image sensor and optical pointing system

Provided is an image sensor and optical pointing system using the same. The image sensor has a plurality of pixels, each pixel including a photocell for receiving light and generating an analog signal having a voltage corresponding to a quantity of the received light, a comparator for, in response to a shutter control signal, comparing the analog signal of the photocell with an analog signal of an adjacent pixel to generate a digital signal for movement calculation, or comparing the analog signal of the photocell with a reference voltage to generate a digital signal for shutter control, and a switch for transferring the digital signal for movement calculation and the digital signal for shutter control in response to a pixel selection signal. The optical pointing system includes a reference voltage generation unit for generating a reference voltage, the image sensor, a signal selector for receiving the digital signal for movement calculation and the digital signal for shutter control, and selecting and outputting one of the digital signal for movement calculation and the digital signal for shutter control in response to a shutter control period selection signal, a movement calculation and shutter control unit for receiving the digital signal for movement calculation to obtain an image of an object and output a movement value of the optical pointing system and the shutter control period selection signal, and receiving the digital signal for shutter control to compare a high-level count value with a maximum count value and a minimum count value and output the shutter control signal.