Research On Key Technologies Of Confocal 3D Measurement Based On DMD

In recent years,with its high accuracy,high resolution and its measurement ability of transparent,translucency and high-light objects,confocal microscopy has been widely used in semiconductor device processing,micro-device surface detection,biomedical detection and some other fields.The efficient parallel confocal technique has also become the focus of scientists' research,and achieved some results.At present,the existing confocal scanning method is to realize omni-directional scanning of the object by the auxiliary displacement of the mechanical device.Mechanical scanning not only causes vibration errors to the measurement,but the scanning efficiency is also limited by the mechanical devices.This project combines the digital micro-mirror device with confocal scanning technology and employs the digital micro-mirror device as the array of illumination pinhole and detection pinhole,so as to realize the efficient and flexible parallel scanning.This paper—— " Research on Key Technologies of Confocal 3D Measurement Based on DMD " ——mainly focuses on confocal microscopy measurement technology,carrying out a series of researches on the combination of digital micro-mirror devices and confocal technology.The main tasks of this paper are as follows:1)Introduced the basic principle of confocal technology and the development status at home and abroad,and elaborated the advantages and disadvantages of various confocal methods at present.2)A confocal measurement structure based on digital micro-mirror device is proposed.The traditional confocal illumination pinhole and detection pinhole are replaced by digital micro-mirror device,which reduces the error caused by pinhole matching.Because each pixel of the digital micro-mirror device has controllable characteristics and high-speed frequency,scanning each plane only requires pattern changes of digital micro-mirror devices controlled by the computer,without mechanical moving.And greatly improve the scanning speed.Finally,a confocal measurement experimental device based on DMD has been builted.In order to ensure the validity and accuracy of the system measurement,the three-dimensional data extraction algorithm is designed,and several fitting algorithms are compared.Secondly,in order to solve the problem of inaccurate measurement caused by experimental errors,algorithms including center point correction and mirror correction are designed to ensure the accuracy of measurement at the algorithm level.3)Because the digital micro-mirror device can be easily controlled by computer,we can change the scan array without changing the system accessories.In the experiment,we designed three scanning schemes for different applications,and proved the feasibility of the scheme by experiments.Finally we analyzed the advantages and disadvantages of each scheme.4)Finally,we measured the surface of standard block,slit,glass and micro-lens array.The reconstructed results are good,and the micro-lens array has a clear outline,which verifies that the system has the ability to measure the surface of high-light object,slit and transparent object.