Optical parameter design and analyses of angle sensor

Abstract

In this paper, the principle and characteritics of an optical critical angle sensor based on the internal-reflection effect are introduced. Then, the method to design the optical parameters of the critical angle prisms and the relationship between these parameters and the system character are discussed with analytical and simulation results. These parameters include the initial angle of incidence, non-parallelism errors of the two parallel faces, and the surface flatness of the reflection faces. A pair of custom-built critical angle prisms providing three internal-reflections is used in our simulation. With the initial angle error is 20 arcsec, the matched non-parallelism errors of the prisms are 30 arcsec and the surface flatness is λ/8, the sensitivity of the system is better than 0.05 arcsec and the nonlinearity is less than 0.3%.