title: Three-shell-based lens barrel for the effective athermalization of an IR optical system.
abstract: We have developed a new IR optical system that consists of three mirrors and four lenses, and that operates in the temperature range 8°C-32°C. This temperature range can induce thermoelastic deformation in the lenses and their mounting subassembly, leading to a large defocus error associated with the displacement of the lenses inside the barrel. We suggest using a new three-shell-based athermalization structure composed of two materials with different coefficients of thermal expansion (Invar and aluminum). A finite element analysis and the experiment data were used to confirm that this new athermalization barrel had a defocus error sensitivity of 11.6 nm/°C; this is an improvement on the widely used conventional single-shell titanium barrel model, which has a defocus error sensitivity of 29.8 nm/°C. This paper provides the technical details of the new athermalization design, and its computational and experimental performance results.
authors: Center for Space Optics, Korea Research Institute of Standards and Science, Daejeon, South Korea.
authors: Ho-Soon
authors: HS
authors: Yang
authors: Hagyong
authors: H
authors: Kihm
authors: Il Kweon
authors: IK
authors: Moon
authors: Gil-Jae
authors: GJ
authors: Jung
authors: Se-Chol
authors: SC
authors: Choi
authors: Kyung-Joo
authors: KJ
authors: Lee
authors: Hong-Yeon
authors: HY
authors: Hwang
authors: Sug-Whan
authors: SW
authors: Kim
authors: Yun-Woo
authors: YW
authors: Lee