UV image intensifier resolution test based on reflective and coaxial optical system

Image intensifier tubes are opto-electronic vacuum devices that amplify very low levels of light into visible levels for the human eye. Resolution which is the ability of an image intensifier or night vision system to distinguish between objects close together is one of the most important parameters. This paper presents a UV image intensifier resolution test equipment. At present UV image intensifier resolution test is still a difficult point, there are mainly two reasons: First, UV is absorbed when transmit the ordinary optical glass. Although UBK-7 and UK-5 have been developed to reduce the absorption in the spectral range of 0.2 μm~0.4 μm, but the absorption is still serious in the 0.3μm. That limits the resolution test. The resolution test based on the transmission optical system can only achieved 40lp/mm. Therefore, based on material reason, the test equipment must use reflective optical system; Second, UV light has the characteristic of scattered in the air. The target image is strongly scattered in the transmission process, leading to the resolution go down soon. So the optical path must be short to reduce scatter.