This paper describes the development of a fiber-optic confocal probe suitable to measuring the central thickness of highcurvature
small-diameter optical ball lenses. The confocal probe utilizes an integrated camera that functions as a realtime
apex-sensing device. An additional camera is used to monitor the shape of the reflected light beam. Placing the
instrument sensing spot off-center from the apex will produce a non-circular image at the camera plane that closely
resembles an ellipse for small displacement. By analyzing the shape of the reflected light spot, we are able to precisely
determine the focus point of the confocal probe relative to the apex point to better than 2-μm precision for ball lenses
with diameters in the range of 3 – 10 mm. The proposed confocal probe offers a low-cost alternative technique for
quality control of ball lenses during the manufacturing process.
© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Armote Somboonkaew ; Ratthasart Amarit ; Sataporn Chanhorm and Boonsong Sutapun
Fiber-optic confocal probe with an integrated real-time apex finder for high-precision center thickness measurement of ball lenses
", Proc. SPIE 8563, Optical Metrology and Inspection for Industrial Applications II, 85630M (November 20, 2012); doi:10.1117/12.999967; http://dx.doi.org/10.1117/12.999967