Optical interference system for simultaneously measuring refractive index and thickness of slim transparent plate

Chia Ming Jan, Chien Sheng Liu, Chun Lin Chen, Yu Ta Chen

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)

Abstract

Measuring the refractive index and thickness of transparent materials is essential in offline or online automated inspection in the manufacturing and industrial fields. We recently developed a novel optical system with two optical paths for simultaneously measuring the refractive index and thickness (>1 mm) of a transparent plate; the developed system allowed for better thickness measurement with a simpler structure and lower cost (C. S. Liu, R. C. Song, and S. J. Fu, Appl. Phys. B 125, 199, 2019). In the present study, the thickness range that can be measured using the developed optical system is reduced to ≤100 μm by using interference methods instead of triangulation methods. The proposed optical interference system is characterized numerically using simulations on the commercial software program ZEMAX and then experimentally tested using a laboratory-built prototype. The experiment results show that the refractive indexes and the thicknesses of the slim transparent plates (thickness ≤ 100 μm) were measured with high accuracy (with maximum measurement errors of 0.0007 and 3 μm for a refractive index n and thickness d, respectively). Consequently, the proposed optical interference system has the potential to be used in the automated inspection of slim transparent materials.

Original languageEnglish
Article number106668
JournalOptics and Lasers in Engineering
Volume145
DOIs
Publication statusPublished - 2021 Oct

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Atomic and Molecular Physics, and Optics
  • Mechanical Engineering
  • Electrical and Electronic Engineering

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