Circuit Design And Realization Of Cooled And Low-light Cmos Imaging System

With the development of science and technology and deeper exploration of the natural world, the technology of low-light imaging detection gets a wide application in fields such as biomedicine, astronomy, geology, public security and military. Though CCD(charge-coupled device) is now the main type of low-light imaging sensor, its application range is seriously restricted by its high price. However, the CMOS(complementary metal oxide semiconductor) image sensor is put into use in recent years. This kind of image sensor provides new opportunities for changing the current situation due to its low cost, high sensitivity and low noise. Thererefore, the study and designation of low-light imging technology based on CMOS imaging sensor will bring great price advantage and application in the future.The paper first analyzes the current research state of low-light CMOS cameras and cooling cameras. Then it puts forward the main design requirements and overall scheme design of the cooled low-light CMOS camera according to the application demand.Based on the above steps, CMOS image sensor of high sensitivity and low noise is applied to capture images and the image datas are transferred by USB(Universal Serial Bus)control chip. To improve imaging quality, a semiconductor cooler is used to lower the operating temperature of CMOS image sensor.The paper presents a detailed introduction of the peripheral circuit of CMOS image sensor and the designation and realisation of USB control chip and temperature control circuit. Finally, a performance test about the main functions of this cooled low-light CMOS camera is carried out. The camera achives clear images in 0.01 lux low-light conditions. It turned out that the cooled low-light camera put forward in this paper exceeds in performance in low-light conditions compared with similar CCD cameras which are now widely used in the market.