@inproceedings{5490976ee78945d09910c18f42bec562,
title = "Tolerance analysis of wide field of view confocal off-axis telescope system using freeform mirrors for common optics MWIR/LWIR sensors onboard UAVs (Linear astigmatism free - Three mirror System D70F1.4)",
abstract = "Linear Astigmatism Free - Three Mirror System (LAF-TMS) is a confocal off-axis system that eliminates linear astigmatism, which is the most critical aberration especially in the large field angle, and therefore, enables the telescope to have a wide field of view. Based on our experience with the telescope, we optimized the LAF-TMS for wavelength ranges of mid-wavelength infrared (3-5 µm) and long-wavelength infrared (8-12 µm) sensors onboard Unmanned Aerial Vehicles (UAVs). It has an entrance pupil diameter of 70 mm, a focal ratio of 1.4, and a wide field of view (FoV) of 6.20° × 4.68°, matching 10.9 mm × 8.2 mm sensor with 17 µm sized pixels (LAF-TMS D70F1.4). The freeform mirrors of LAF-TMS D70F1.4 are optimized to eliminate the high order aberration. As a result, LAF-TMS D70F1.4 can achieve high-quality optical performance over a wide FoV without any additional correcting lenses. We performed the sensitivity analysis and the Monte-Carlo simulations as the feasibility study. During the sensitivity analysis and the Monte-Carlo simulation, decenter, tilt, despace, and surface RMS errors of three mirrors were analyzed. From the sensitivity analysis, we investigated 80% Energy Encircled Diameter by single factor perturbations. The system tolerance limits were calculated using the Monte-Carlo method with a normal distribution of errors. According to the results, we confirmed that the LAF-TMS D70F1.4 was feasible considering general fabrication and alignment tolerances.",
keywords = "Dual-band, Freeform mirror, Infrared, Linear astigmatism, Monte-Carlo simulation, Off-axis, Telescope, Tolerance analysis",
author = "Jimin Han and Woojin Park and Seunghyuk Chang and Sunwoo Lee and Hojae Ahn and Kim, {Dae Wook} and Kim, {Geon Hee} and Lee, {Dae Hee} and Hanshin Lee and Soojong Pak",
note = "Publisher Copyright: {\textcopyright} 2020 SPIE.; Electro-Optical and Infrared Systems: Technology and Applications XVII 2020 ; Conference date: 21-09-2020 Through 25-09-2020",
year = "2020",
doi = "10.1117/12.2573698",
language = "English (US)",
series = "Proceedings of SPIE - The International Society for Optical Engineering",
publisher = "SPIE",
editor = "Hickman, {Duncan L.} and Helge Bursing",
booktitle = "Electro-Optical and Infrared Systems",
}