Research on Optical Axis Adjustment Method of Three-band Optical System

We developed a system to align portable binocular optical axes in the three spectral bands of visible light, short-wave infrared (SWIR), and long-wave infrared (LWIR). The two left and right optical axes of the binocular were coaxial with the mechanical axis of the lens tube, and the two optical axes were parallel to each other. The three spectral bands included 0.4.0.7 μm in the visible light for daytime observation, 1.55 μm in the short-wave infrared light for laser ranging, and 8.12 μm in the long-wave infrared light for nighttime observation. Due to the three functions of portable binoculars, their optical system is complex and small, which increases the difficulty of system assembly and optical axis alignment. The developed system configured five optical splitters into an F-type distribution and synthesized the input-separated equidistant three-wavelength parallel light into a beam of coaxial light with a CCD sensor. The system contained a beam splitter to form an F-shaped composite autocollimator for fast optical axis alignment. In the optical axis alignment, the maximum vertical error was 0.6° and the maximum horizontal error was 1.4°.