Design of Highly Compact Catadioptric Freeform Linear-Scanning Optical Systems

Abstract

Laser scanning systems are adopted for diverse applications in imaging, printing, and material processing, and there is a growing trend toward volume miniaturization without compromising optical performance. In this work, a highly compact optical configuration is proposed by combining catadioptric architecture with freeform optics. A multi-stage design method, from starting point acquisition to fine-tuning, is proposed, with particular attention to concurrently controlling physical layout and optical performance. Two systems were designed, demonstrating an average RMS wavefront error below 0.006λ and a linearity error under 0.3% over a 216 mm scanning width. The spot size deviation is below ±9%, and the position deviation is kept within half the diffraction-limited spot diameter over a ±2 mm depth of field. Compared to a conventional freeform lens design, the proposed systems reduce the total length by over 37.7%. The significant reduction in size achieved paves the way for next-generation portable and embedded laser scanning devices.