Wide-Spectrum Microscope with a Long Working Distance Aspherical Objective Based on Obscuration Constraint

Weibo Wang; Chao Wang; Jian Liu; Jiubin Tan

doi:10.3390/s16111886

Wide-Spectrum Microscope with a Long Working Distance Aspherical Objective Based on Obscuration Constraint

Sensors (Basel). 2016 Nov 9;16(11):1886. doi: 10.3390/s16111886.

Authors

Weibo Wang^{1

2}, Chao Wang³, Jian Liu⁴, Jiubin Tan⁵

Affiliations

¹ Institute of Ultra-Precision Optoelectronic Instrument Engineering, Harbin Institute of Technology, Harbin 150001, China. weibo.wang@eng.ox.ac.uk.
² Department of Engineering Science, University of Oxford, ParksRoad, Oxford OX1 3PJ, UK. weibo.wang@eng.ox.ac.uk.
³ Institute of Ultra-Precision Optoelectronic Instrument Engineering, Harbin Institute of Technology, Harbin 150001, China. wangchao.hit@gmail.com.
⁴ Institute of Ultra-Precision Optoelectronic Instrument Engineering, Harbin Institute of Technology, Harbin 150001, China. liujian@hit.edu.cn.
⁵ Institute of Ultra-Precision Optoelectronic Instrument Engineering, Harbin Institute of Technology, Harbin 150001, China. jbtan@hit.edu.cn.

Abstract

We present an approach for an initial configuration design based on obscuration constraint and on-axis Taylor series expansion to realize the design of long working distance microscope (numerical aperture (NA) = 0.13 and working distance (WD) = 525 mm) with a low obscuration aspherical Schwarzschild objective in wide-spectrum imaging (λ = 400-900 nm). Experiments of the testing on the resolution target and inspection on United States Air Force (USAF) resolution chart and a line charge-coupled device (CCD) (pixel size of 14 μm × 56 μm) with different wavelength light sources (λ = 480 nm, 550 nm, 660 nm, 850 nm) were implemented to verify the validity of the proposed method.

Keywords: aspherical Schwarzschild objective; long working distance; low obscuration; wide-spectrum microscope.