General design algorithm for stray light suppression of a panoramic annular system

Abstract

In this work, a universal algorithm for designing a panoramic annular lens (PAL) system free from stray light is proposed. The impact of a given stray light path to the optical system could be estimated without running a full stray light analysis process, which allows designers to eliminate troublesome stray light paths by optimizing lens parameters at an early stage of optical design. A 360° ×(40°-100°) PAL system is designed and implemented to verify the proposed method. Simulation shows that the point source transmittance (PST) decreases by 2 orders of magnitude at a specific field-of-view (FoV) range after optimizing the system. Experimental results show perfect consistency with the simulation predictions, which indicate that two types of stray light are totally eliminated in the demonstrated system. This stray light analysis and suppression method provides a promising approach for the research and development of ultra-wide angle high performance optical systems.

Comprehensive stray light analysis and feature rays identification for a panoramic annular lens

“…LRW is the annotation in previous literature. 4 The effects of the points annotated as URW1 and URW2 are just the opposite. LRW and URW stand for Lower Ray Waypoint and Upper Ray Waypoint according to the original peper.…”

“…An optical design algorithm for suppressing stray light in PAL systems based on feature ray identification was proposed recently. 4 The feature ray identification is a vital step in calculating relative amount of a specific stray light. Treating stray light rays like imaging rays, the definition of feature rays is given.…”

“…LRW and URW stand for Lower Ray Waypoint and Upper Ray Waypoint according to the original peper. 4 A marginal ray crossing these waypoints is identified as a feature ray. This concept helps to calculate the amount or risk of a certain type of stray light, and has great significance in the design algorithm.…”

“…Recently, a general design algorithm to control several troublesome stray light in PAL systems was published. 4 Prior to the derivation of this design method, a comprehensive stray light analysis is required. This paper discusses stray light characterizations in common PAL systems with experimental validation.…”