High-speed, high-precision focal length measurement using double-hole mask and advanced image sensor software

Binh Xuan Cao; Phuong Le Hoang; Sanghoon Ahn; Jeng-O Kim; Heeshin Kang; Jiwhan Noh

doi:10.1016/j.isatra.2018.01.018

High-speed, high-precision focal length measurement using double-hole mask and advanced image sensor software

ISA Trans. 2018 Mar:74:239-244. doi: 10.1016/j.isatra.2018.01.018. Epub 2018 Feb 1.

Authors

Binh Xuan Cao¹, Phuong Le Hoang², Sanghoon Ahn³, Jeng-O Kim³, Heeshin Kang³, Jiwhan Noh⁴

Affiliations

¹ Department of Laser and Electron Beam Application, Korea Institute of Machinery & Materials (KIMM), Daejeon 34103, South Korea; Department of Nano-Mechatronics, Korea University of Science and Technology (UST), Daejeon 34113, South Korea.
² Department of Material Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, South Korea.
³ Department of Laser and Electron Beam Application, Korea Institute of Machinery & Materials (KIMM), Daejeon 34103, South Korea.
⁴ Department of Laser and Electron Beam Application, Korea Institute of Machinery & Materials (KIMM), Daejeon 34103, South Korea; Department of Nano-Mechatronics, Korea University of Science and Technology (UST), Daejeon 34113, South Korea. Electronic address: njw733@kimm.re.kr.

PMID: 29366508
DOI: 10.1016/j.isatra.2018.01.018

Abstract

A cutting-edge precision technique for computation of focal length of a positive lens with double-hole mask is described. The technique is simple and versatile due to incorporation of the updated functions of image sensor device that supports reading the distance between beam spots instantaneously while the position of the specimen is being changed, as well as the reduction in several challenging measurement steps. Furthermore, this technique does not require prior knowledge of distances in the optical setup. High accuracy in focal-length measurement is obtained by precise beam spot distance analysis using image sensor integrated software. The acquired data exhibit considerably high precision and reproducibility.

Keywords: Double-hole mask; Focal length measurement; Image sensor; Laser micromachining.