Open AccessMiniature adjustable-focus endoscope with a solid electrically tunable lens
Author(s) -
Yongchao Zou,
Wei Zhang,
Fook Siong Chau,
Guangya Zhou
Publication year - 2015
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.23.020582
Subject(s) - optics , lens (geology) , focal length , dioptre , materials science , focus (optics) , distortion (music) , optical power , ray tracing (physics) , bundle , perpendicular , fabrication , cylindrical lens , optoelectronics , physics , medicine , amplifier , laser , geometry , mathematics , visual acuity , cmos , alternative medicine , pathology , composite material
The design, fabrication and characterization of a miniature adjustable-focus endoscope are reported. Such an endoscope consists of a solid tunable lens for optical power tuning, two slender piezoelectric benders for laterally moving the lens elements perpendicular to the optical axis, and an image fiber bundle for image transmission. Both optical and mechanical designs are presented in this paper. Dynamic tuning of optical powers from about 135 diopters to about 205 diopters is experimentally achieved from the solid tunable lens, which contains two freeform surfaces governed by 6-degree polynomials and optimized by ray tracing studies. Results show that there is no obvious distortion or blurring in the images obtained, and the recorded resolution of the lens reaches about 30 line pairs per mm. Three test targets located at various object distances of 20 mm, 50 mm and 150 mm are focused individually by the endoscope by applying different driving DC voltages to demonstrate its adjustable-focus capability.