Research On Optical Microscopic Auto-Focus Based On Stripe Projection

Autofocus technology is widely used in optical image measurement,and the requirements for autofocus technology vary depending on various imaging and measurement requirements.In industrial microscopic measurements,environmental fretting and vibration can cause the object to be measured off the focal plane of the microscope,and autofocus technology is critical in optical microscopy.In this paper,an autofocus microscope system based on projection stripe is designed for the autofocus problem of defect microscopy in liquid crystal panel production,and the design of the optical path is simulated to verify the feasibility of the system;The system was built on the test bench to study the key parameters,the design and assembly completed an autofocus microscope system finally.The specific research work is as follows:(1)Introduced the development of autofocus methods at home and abroad and the research status at home and abroad,and expounded the significance of this paper.The existing autofocus technology is classified,the principle of optical microscope is expounded,and several methods of focusing are analyzed from the imaging principle.The mathematical model of the focusing process of optical microscope is constructed.(2)Designing an autofocus microscope system based on fringe projection,using Tracepro to simulate the optical path of the system.Analyze the advantages and disadvantages of different definition evaluation functions,and select the resolution evaluation function for processing raster images.The feasibility of the fringe projection-based autofocus microscope system was verified by focusing the different objects under the simulation system.(3)Build an experimental system using digital projection grating,analyze the influence of grating period on the focusing range of the system,experiment with equal period grating,variable period grating and different objective lenses,and study the system technical parameters to obtain the optimal focusing performance;Design and process the mechanical structure of the digital projection grating microscope autofocus system,assemble,debug and test the system to verify the focusing performance of the system;Finally,the system technology is summarized and the error source of the system is analyzed.