Research On Ultrasonic Laser Digital Holographic Microscopy Synchronous Control System

With the rapid development of manufacturing products for micro devices,the detection of microstructure defects in these products has gradually become a research hotspot.Failures caused by micro-defects often cause the entire part to fail,which in turn poses a safety hazard to the entire system.Based on the ultrasonic digital holographic microscopy platform,this paper studies the principle of digital holographic recording and reproduction of images,designs and verifies the synchronous control system,and captures and collects the micro-mechanical surface vibration holographic interferogram for the detection of microstructure defects.This has important theoretical significance and application value for the detection of microstructure defects.Aiming at the problem of holographic image acquisition in ultrasonic digital holographic microscopy system,digital holography technology,including the principle of recording and reproducing image of digital holography was researched,besides.,researching the key parameters in digital holographic shooting experiment,recording distance,light intensity ratio of material reference and angle between object light and reference light and so on.The communication relationship between the hardware in the ultrasonic digital holographic microscopy experiment and the composition of each subsystem were analyzed.The overall scheme of the software programming of the ultrasonic digital holographic microsynchronous control system and the functions of each module were determined.According to the design requirements of the system,the design task of the ultrasonic digital holographic microsynchronous control system is analyzed and determined.According to the system,the acquisition pulse is selected for the output pulse and the physical channel,the driving mode of each hardware of the system and the interface signal type are studied,and the pulse laser and CCD drive scheme.Study and analyze the control mode and internal working sequence of the CCD to realize the CCD exposure parameter setting,holographic image acquisition and real-time display and storage functions.Combined with the working sequence between the pulse laser,CCD and signal generator,the delay controllable synchronous control system is designed;finally,the integration of the two modules is realized.According to the developed ultrasonic digital holographic microsynchronous control system,the functionality and testing accuracy were verified.Taking the resolution plate as the experimental object,the hologram was collected,and multiple sets of contrast experiments were carried out to verify the parameter setting function of the CCD.By adjusting the light intensity ratio of the reference material,the selected range of the light intensity ratio parameter of the object in the reflective digital holographic microscopic detection experiment is realized.Taking the micro-defects on the surface of the aluminum plate as the experimental object,the appropriate delay time of each channel was obtained through multiple sets of experiments,and the vibration holographic interferogram of the surf'ace of the test piece was captured,which proved the practicability and effectiveness of the system.