학술논문
Range-Extended Confocal Chromatic Sensor System for Double-Sided Measurement of Optical Components With High Lateral Resolution
Document Type
Periodical
Author
Source
IEEE Transactions on Instrumentation and Measurement IEEE Trans. Instrum. Meas. Instrumentation and Measurement, IEEE Transactions on. 71:1-8 2022
Subject
Language
ISSN
0018-9456
1557-9662
1557-9662
Abstract
This article presents a strategy to break the tradeoff between the thickness measuring range of a confocal chromatic sensor (CCS) and its lateral imaging resolution. By combining the sensor with a linear stage, the thickness measuring range is no longer limited by chromatic dispersion, but by the focusing power of the sensor optics. The principle is demonstrated with a prototype setup that utilizes a CCS with a spot size of 6 $\mu \text{m}$ and a spec-sheet thickness measuring range of 300 $\mu \text{m}$ . By implementing the proposed mechatronic approach, a successful extension of the measuring range by a factor of 17 is achieved while preserving the lateral resolution of 2.46 $\mu \text{m}$ for thickness measurements. The proposed measurement scheme is validated by measuring lateral surface features on a 1.2-mm-thick lenslet array from the backside.