Design of a miniaturized dual-view objective lens system for electronic endoscopy

This study presents the design of a miniaturized dual-view objective lens system for electronic endoscopy. By modifying the second reflective surface of the panorama annular lens, the issue of limited light aperture in the forward-view structure of existing dual-view panoramic systems can be addressed. The forward-view structure captures light within a ±45^∘ range, whereas the side-view structure covers (45^∘-85^∘)×360^∘, resulting in a total field of view (FOV) of ±85^∘ with a compactness ratio of 1.48. The system had an overall length of 7.62 mm and a maximum outer diameter of 4.1 mm. At a Nyquist frequency of 167 lp/mm, the modulation transfer function (MTF) exceeds 0.35 across the full FOV, with a relative illumination greater than 0.7 and an <i>f</i>-<i>θ</i> distortion of less than 10%. This system achieves wide-angle imaging under miniaturization constraints and has significant application value.