Research On Technology Of CCD Mosaic Camera

Ground-based large aperture and large field photoelectric telescopes undertake important work in astronomical surveys and debris observations,which has brought about the demand for large target surface detectors.Although 6k×6k,9k×9k,and10k×10k target size detectors have been developed,the size of the target surface of a single CCD or CMOS detector still cannot meet the needs of large-diameter and large-field optical detection.The method of multi-detector mosaic technology to solve the detection of large aperture and large field of view has become a practical technical approach.In this paper,the multi-CCDs target mosaic technology in the CCD mosaic camera and the cooling and insulation technology of the mosaic camera are studied.The key technology and technical difficulties in target surface stitching,camera cooling and insulation are analyzed,as well as the effects of CCD chip parameters and target surface stitching accuracy on the detection of space weak energy targets.A mosaic scheme of 9 chips of 4k×4k CCD 3×3 mosaic camera based on three-point kinematics support was designed to achieve high-precision assembly of non-customized CCD large target surfaces through more convenient assembly and adjustment methods under general machining accuracy conditions.A flatness detection scheme for target surface assembly based on the principle of non-contact contour measurement was designed to achieve the flatness detection of large-scale mosaic target surface.The gravity deformation of the target surface of different cold plate materials is simulated and analyzed.Under the premise of ensuring that the gravity deformation of the target surface does not hinder the splicing accuracy,the cold plate material and the thermal conductivity are comprehensively considered,and the cold plate material is selected.The importance of CCD chip cooling for the observation of weak energy targets and the factors affecting camera cooling are analyzed.The heat leakage path of thecamera is analyzed,and the adiabatic design of different heat leakage paths is carried out.Based on the theoretical calculation of camera heat leakage,a vacuum insulation cooling scheme for camera Dewar was designed.In the Dewar thermal simulation analysis of the camera,a cooling temperature setting solution is used to solve the power requirement.The temperature distribution of the camera Dewar and chip components is solved.At the same time,the power required for the camera cooling at the designed cooling temperature is obtained.Through the analysis of the temperature distribution inside the camera Dewar and the power required for the chip cooling,combined with the cooling performance of the camera cooling scheme,the feasibility of the camera cooling and heat insulation scheme is verified.