Research On The On-line Optical Transfer Function Detection And The Accurate Positioning Control

With the development of modern science and technology, optical system imaging technology is becoming widespread in the field of industrial testing application. It especially occupies a pivotal position in the automation and intelligent control. So it is important to study the quality detection and various evaluation methods of optical system imaging. There are a lot of methods to evaluate imaging quality of an optical system, such as, rate of star testing method, differential method, wavefront aberration method, optical transfer function detection method. And optical transfer function (MTF) detection method is recognized the most objective and effective optical image quality detection method currently. Nowadays, optical transfer function detector is moving towards automation and standardization. The automatic version of the MTF detector has a high requirement of the accurate positioning, as well as the requirements of the repeatability and stability.The automatic version of the MTF detector has met the problem of positioning accuracy and system’s stability when it’s used for industrial production line. In this paper, based on the theories of optical transfer function and the accurate position detection technology, we propose the closed-loop position feedback system. And then we integrated the closed-loop positioning system into the automatic MTF detection system in both the software and hardware aspects. The position accuracy of the detection system reached±1μm.After the above research, we test the repeatability and stability of the improved MTF detection system and get a good measurement result:the repeatability and stability of the MTF detection platform which based on the closed-loop feedback control meet the requirements of industrial production. Finally, based on the high accuracy of the repeatable positioning and the good repeatability and stability of MTF detection system, we have investigated the MTF dispersion of the lens by using the knowledge of standard deviation and range of the reference data of mathematical statistics, and come to the following conclusion:the discrete data meets the requirements of the scanning lens manufacturing. The testing system has implanted in the production line to evaluate the quality of the scan lens.