Chao-Wen LIANG^* and Chien-Fu OU

Department of Optics and Photonics, National Central University, No. 300, Jhongda Rd., Jhongli City, Taoyuan County 32001, Taiwan, R.O.C.

(Received July 15, 2008; Accepted April 14, 2009)

A quantified focal plane testing method, termed phase-shifting grating-slit test, is demonstrated by utilizing a micro liquid crystal display. In contrast to the setup in the Ronchi Test, an incoherent illuminating grating is used and an optical slit is located at the image plane of the tested lens to modulate the aberrated wavefront. With the micro liquid crystal display generating and phase shifting the incoherent illuminating grating with variable frequency, a higher measurement dynamic range can be achieved on demand.

Key words: grating-slit test, phase shifting, liquid crystal display, surface testing, grating

^*E-mail address: cwliang@dop.ncu.edu.tw