Impact of surface irregularities on the optical performance of the injection-molded right-angled triangular plastic prisms: Experiment and numerical simulation

A right-angle triangular plastic prism is manufactured by injection molding (IM) technique which is the most efficient mass production technology for high volume applications. The surfaces produced on the right-angle triangular plastic prism are loaded with irregularities which distort prism performance and make wavefront aberration. The quality of the plastic prism in case of optical performance and wavefront peak to valley were analyzed by Zemax simulation and compared with the measurement data. The latter was measured with a µPhase interferometer by Trioptics operating based on the Twyman-Green principle. We validated the accuracy of our simulation by comparing the calculated results with interferometer measurement. Levering this confirmed accuracy, we employed Zemax to further evaluate the impact of legs and hypotenuse surfaces of the IM right-angle triangular plastic prism on its optical performance. Our primary focus was on identifying which of the legs or hypotenuse most significantly affects its optical output. Our findings indicate that the hypotenuse surface roughness exerts the most substantial influence on the output optical performance. This result has critical implications for the design and optimization of optical systems incorporating right-angle triangular prisms. By refining the characteristics of the hypotenuse surface, significant improvements in optical performance can be achieved, thereby enhancing the overall efficiency and accuracy of the system. These findings provide valuable insights for optimizing the design of optical systems incorporating right-angle triangular prisms, highlighting the importance of precise surface analysis and refinement.