Scene simulation optics in testing of dual-field angle infrared imagers

摘要

The paper outlines a simulation system based on the IR liquid crystal light valve (LCLV) and describes the design of the optical systems for simulator including the variable magnification lens and the projection optics. The simulator is used in testing of an infrared imaging system, which has two field angles of 6° and 8°. The variable magnification lens between the LCD panel and the LCLV produce a visible image at varying magnifications on the LCLV. The projection optics collimates the infrared image which is inverted by the LCLV to generate an infrared scene in the 8～12μm waveband. The varying image size meets the need of the test IR imaging system, which field angle varies. The projection optics is designed for a constant field angle and constant entrance pupil. Thus the IR image always fills the entrance aperture and FOV of the test optical system. A long working distance and sufficient exit pupil distance of the projection optical system ensure the mechanical and the optical assembly, and match the simulator exit pupil to the imagery system entrance pupil. The Modulation Transfer Function (MTF) and spot diagram show the perfect image quality of the projection optics.