Design of a dual-band co-aperture synchronous zoom security optical system

With the development of the security industry, the demand for complex environment detection lenses is rising. For the existing dual-band synchronized imaging zoom optical system, there exist problems such as chromatic aberration, difficulty in achieving a high synchronized zoom ratio, and low resolution, as well as poor image quality when the high synchronized zoom ratio is achieved. We designed a dual-band co-aperture zoom optical system capable of visible (VIS) (436-656 nm) and short-wave infrared (SWIR) (1300-1700 nm) imaging, with a focal length ranging from 23 to 190 mm and a zoom ratio of about 8.26×. The system adopts the dual optical path structure of the beam-splitting prism to realize dual-band synchronized imaging. Meanwhile, the large-diameter lens in the co-aperture part is made of ultra-low dispersion glass and uses the double lens of coronal and heavy flint glass to reduce chromatic aberration, and the residual chromatic aberration and other aberrations are corrected by different structural lens sets after beam splitting. The design results show that both bands have high resolution and good imaging quality, with 5 megapixels in the VIS band and 1.3 megapixels in the SWIR band. The zoom structure is simple, and the cam curve is smooth without an inflection point, which is suitable for military and civilian fields.