Photoelectric autocollimator is an important instrument for measuring small angles, inspecting straightness of the guide track of a machine and planeness of a platform. The sensitivity of photoelectric autocollimator depends on the collimator structure and parameters. Several methods intended to improve this were found in references. But they could not be widely used because some limitations. In this paper, a newly, designed auto-reflector is proposed, which can doubly increase the sensitivity of the system. Working principle, characteristics, and several structure outlines of the reflector are described in detail. The photoelectric structure is introduced. Analog test is also described.
