Error analysis and tolerance allocation in optical system

Abstract

In this thesis, error analysis and tolerance allocation method for optical system are presented. Using optical systems analysis tool, the NFR (Near Field Recording) system are designed. After design and fabrication of NFR system, the performance test for the NFR system is done. To enhance the optical performance of the NFR optical head, a new design optical head is suggested. The error analysis for the optical system of NFR system is also presented. And the effects of assembly and manufacturing tolerances of the NFR optical head are simulated. The tolerances analysis result indicates that the optical direction tolerance is very tight. It needs to allocate and compensate the tolerances of the NFR optical head. The position of the CL (Collimating Lens) is adjusted to compensate the tolerance. Finally, optimal compound tolerance allocation using SUM (summation) method, WOW (worst on worst) method, RSS (root sum square) method, and Monte-Carlo method are proposed. In order to test the performance of the optical head and the tolerance allocation method which I proposed, we designed and fabricated a tolerance allocation evaluation system for the optical head of NFR system using interferometer which can detect the RMS wavefront aberration of the optical head. Using the system, we evaluated tilt, decenter and defocus tolerances in the optical head of the NFR system. And show the RMS wavefront aberration characteristics of the optical head of the NFR system.