Research On Fabrication Of Aspheric Microlens Array Based On Turning Mask

In the existing mature processing methods,the fabrication of aspheric microlens array structure can be divided into two categories: photolithography and single point diamond turning.Lithography can be used for processing of inorganic materials,such as quartz and silicon,but the micro optical cutting technology has never been a good solution to the control of the surface shape of the micro and nano structures;the single point diamond turning technology can realize the accurate control of the opposite type,but it is difficult to process the inorganic and brittle materials.In view of the unique physical properties of silica glass,in order to solve the two difficult problems of quartz aspheric microlens array processing,such as poor controllability and low surface accuracy,a method of making quartz glass based on turning mask is proposed.The two technologies of single point diamond turning and reactive ion etching are innovatively combined.The mask layer is made by single point diamond turning,and then the mask pattern is transferred by reactive ion etching.The fabrication of quartz glass aspheric microlens array elements is completed.The masking materials were screened.The existing masking materials,such as photoresist,PMMA and other materials,were analyzed and experimentation,and physical properties and their performance in reactive ion etching were optimized.PMMA is selected as the most suitable masking material,and the problem of poor corrosion resistance of PMMA is improved.The new material is used to make the mask,and the quartz glass aspheric microlens array is obtained by making single point diamond turning mask pattern and etching on the mask surface.The experimental results are compared with the expected parameters.The analysis shows that the root mean square error of the quartz glass element manufactured by this method is 1.155 nm and the accuracy of face shape error is 0.47%.The experimental results show that this method has the advantages of single point diamond turning technology,high surface accuracy,high processing stability and mature technology,and good anisotropy of reactive ion etching technology.This method has great potential for development,and it also provides a strong support for the wider application of quartz glass materials.