Electromagnetic MOEMS Scanning Grating Micromirror Package Structure Design And Performance Test

The electromagnetic Micro-Optical-Electro-Mechanical-System(MOEMS)Scanning Grating Micromirror as the core device of a miniature NIR spectrometer is an optical micro-mirror.It uses micro-machining technology to integrate grating,driver and sensor,and can realize mechanical scanning and optical spectroscopy simultaneously.The electromagnetic MOEMS Scanning grating micromirror has the advantages of small size,low power consumption and the ability to replace expensive array detectors with single tube detectors.It is a new generation of core spectroscopic devices to replace traditional NIR and mid-infrared spectroscopy equipment.The efficient and stable operation of the electromagnetic MOEMS Scanning Grating Micromirror requires not only an optimized structural design of the micromirror,but also a miniaturized,reliable packaging structure and a streamlined assembly process to meet the future needs of the industrialized of this product.The design of packaging structures for electromagnetic MOEMS Scanning Grating Micromirrors is therefore of great practical value and research significance.At present,the electromagnetic MOEMS Scanning Grating Micromirror is limited by its structure and size,making it difficult to withstand large external shocks.The existing packaging structures and assembly procedures are complex,and other problems,which seriously restrict the industrial development of electromagnetic MOEMS Scanning Grating Micromirror.Based on this,this paper presents a theoretical analysis of the electromagnetic MOEMS Scanning Grating Micromirror,proposes a package structure and optimizes the design of housing parameters,and simulates and analyses the impact and vibration resistance as well as electromagnetic coupling and thermal stability performance of the micromirror before and after the package.Then the research manufactures the package structure and conducts testing experiments on the electromagnetic MOEMS Scanning Grating Micromirror.The main research work of the thesis is as follows:(1)In order to solve the main problems of the electromagnetic MOEMS Scanning Grating Micromirror package such as the complex structure and assembly process.Based on the analysis of its working principle and structural characteristics,the overall design of the electromagnetic MOEMS Scanning Grating Micromirror package based on sandwich package structure is proposed,including a PCB board to interconnect the micromirror with the external circuit,a package cover plate with rectangular through-hole and a package base.In order to achieve the required industrialized of the package structure,the drive coil and permanent magnet spacing in the drive system are optimized to achieve maximum magnetic field strength in the smallest package housing size.By simulating the impact resistance of the package housing,the optimum dimensions are obtained: 30mm×22mm×9.1mm for the overall package housing,30mm×22mm×3mm for the package cover,30mm×22mm×4.5mm for the package base,and 30mm×22mm×1.6mm for the PCB board.(2)The finite element analysis model of the electromagnetic MOEMS Scanning Grating Micromirror before and after encapsulation are established,and the simulation analysis of modal,shock and vibration resistance are completed,and the results show that the modal state of the electromagnetic MOEMS Scanning Grating Micromirror before and after encapsulation remains unchanged and the motion mode remains unchanged.Shock and vibration resistance of encapsulated devices is improved compared to preencapsulation.In addition,an analytical model of multi-physics field coupling before and after encapsulation of the electromagnetic MOEMS Scanning Grating Micromirror is established for electromagnetic thermal simulation,and the results show that the electromagnetic coupling performance of the device before and after encapsulation without changing significantly.Due to heat transfer,the temperature of the encapsulated micromirror during operation decreased by 18.5%.It shows that the micromirror is with good temperature stability.(3)The test platform of the electromagnetic MOEMS Scanning Grating Micromirror is built to carry out experimental test studies.The fabrication of the package housing of the device is completed and the matching assembly process is proposed.The test results show that the resonant frequency of the device is 604.4Hz,the maximum deflection angle is 6.14°,the sensitivity of the angle sensor is 1.4425 m V/°,the deflection angle and the drive current,the deflection angle and the voltage of the angle sensing coil have high linearity,and the electromagnetic coupling performance does not change significantly.The device operated for a long time with a resonant frequency change of 0.03% and a deflection half-angle reduction of about 2.3%,which does not have a significant impact on the operating performance of device.The device operates at temperatures below 40°C,the resonant frequency dropped by 0.083% and the deflection half-angle by 4.6%,indicating that the packaging structure of the electromagnetic MOEMS Scanning Grating Micromirror is capable of ensuring stable and effective operation over long periods of time and at normal temperature.In addition,the packaged electromagnetic MOEMS Scanning Grating Micromirror is capable of withstanding three repeated impact tests at100 g in the X,Y and Z directions.The device with a 20 g vibration resistance.