Image Sensor Knowledge Multi-resolution Surveillance Camera Cooled CCD

    What is a cold CCD camera? This topic starts with CCD. CCD is the abbreviation of charge-coupled device. Its function is to convert light signals into electric charges and represent the differences in light signals through the differences in electric charges.

    CCD was developed by Bell Labs in 1969, and Sony Central Research Institute launched large-scale research based on it in December of the same year. It was successfully commercialized in 1980 and officially entered the mass production stage. CCD image sensors began to officially enter people's lives and affect every aspect of people's lives.

    From the function of CCD, we know that the first step in converting light signals into electrical signals is to have enough light signals. The second is to ensure that the conversion efficiency of each pixel is consistent and noise-free when converting them into electrical signals, so that we can get a perfect image.

    However, in actual shooting, we often cannot get the ideal intensity of light signal (such as fluorescence and chemiluminescence shooting). At this time, it is required to accumulate the photon signal to obtain a strong enough light signal. As a photoelectric conversion device, its materials and physical properties are not ideal. Therefore, the interior and surface of the sensor inevitably contain impurities. Due to thermal excitation, impurities will generate electrons, which are also captured by electron traps and become charge, thereby destroying the efficiency of its photoelectric conversion and the image produced. We call this noise dark current noise. The number of electrons generated by impurity thermal excitation is related to time. Therefore, when shooting in low light and accumulating photon signals, dark current noise will be very obvious. How to reduce dark current has become the most important part of low-light shooting. From the cause of dark current, we can know that temperature is the main reason. Therefore, scientists cool the CCD to make it work at a lower temperature, thereby reducing the generation of dark current and improving the signal-to-noise ratio of long-term low-light shooting images. This CCD with a cooling module is called a cold CCD. Compared with ordinary CCDs, cold CCDs have less dark current, higher signal-to-noise ratio, and can shoot ideal fluorescence or chemiluminescence patterns.