Interferometer Test System Improvements, And Measuring Range Extension

An example of improvement of O80mm phase-shifting Twyman interferometer is given in this paper .The goal is to expand the range of measurement and make the interferometer have higher automation function so as to improve the test system. The problem is originated from three ways, including, adding zoom lens, self-adapting light power, automatical control system of zoom lens. The digital signal processor (DSP) is used to control step motor that drives the gradually variable filter to adjust the light intensity induced by the change of zoom lens. DSP used in optical system ensures the precision of measurement and at the same time makes the adjusting light intensity have the characteristic of real time and automation function. The control circuit of zoom lens is designed which makesOSOmm phase-shifting interferometer can be operated very conveniently. It becomes a system of photo-electricity and makes the research sample of interferometer become a product. This paper includes: the design of beam path of the zoom unit, self-adapting light intensity, the design of the circuit to control the zoom lens, the design of anti-jamming of circuit system and the system debugging. This technique can be used in other type of interferometer with different aperture.