A Large Aperture Long Focal Length Foldback Infrared Uncooled Imaging System

Abstract

The large aperture and long focal length turn-back infrared uncooled imaging system of the present invention is special in that it includes a secondary reflector, a primary reflector, a lens group and an uncooled infrared detector arranged sequentially along the optical axis from outside to inside, and the main There is a circular through hole in the center of the reflector; the main reflector reflects the incident light in the scene to the secondary reflector, and the light reflected by the secondary reflector passes through the through hole and then enters the lens group. It focuses on an uncooled infrared detector to achieve long focal length uncooled infrared imaging. In the infrared uncooled imaging system of the present invention, the incident light is firstly reflected forward by the main reflector, and then reflected backward by the secondary reflector, which solves the problem that the focal length of the uncooled infrared system cannot be large due to the limitation of the size of the germanium material. The problem is that it can reach a focal length of thousands of millimeters; it has the advantages of long focal length, compact structure, and large field of view, and can be widely used in optoelectronic imaging fields such as aviation and aerospace.

Description

technical field [0001] The present invention relates to an uncooled imaging system, more specifically, to a large aperture and long focal length turn-back infrared uncooled imaging system. Background technique [0002] Due to the technical level of the current uncooled infrared focal plane detector, the temperature sensitivity cannot be as small as that of the cooled infrared detector. It is 50mk-80mk, while the cooling type focal plane detector is less than 20mk. At the same time, the current uncooled infrared detectors are mainly imported. The development of domestic uncooled detectors is in its infancy, and there is a big gap with foreign products. However, the performance of uncooled infrared detectors that can be imported into my country is not as good as the products made in the United States and France. There are differences in detectors used in different countries. In addition to temperature sensitivity (NETD), there are also differences in blind element rate and det...

AI Technical Summary

Problems solved by technology

However, the materials used for long-wave infrared are relatively limited at present. The mature materials are generally germanium single crystal and zinc selenide. Zinc selenide can synthesize a large surface shape, but the material itself is expensive and zinc selenide with excellent optical properties It is mainly imported, and foreign countries have regulations on this; we have a large number of germanium mines in China, and germanium is only cheaper than zinc selenide, and its optical properties are better than zinc selenide, but the growth process of germanium single crystals currently has the largest diameter It is only about 350mm, which determines that the focal length of the uncooled system we can get is about 400mm. The focal length of this size is very small in visible light systems, cooled infrared systems, and astronomical telescope systems. Far

Images