Fabrication And Design Of A Dammann Grating In DMD-based Digital Maskless Lithography

Digital lithography technique based on Digital Mirror Device(DMD)have the characteristics of flexibility and high efficiency.This technology is widely used in many fields,such as circuit board manufacturing,micro-optical device manufacturing,and microfulid manufacturing.Micro and nano optics are small in size with various functions,and are particularly suitable for the needs of miniaturization and high integration.For example,the core device of the structured light projection module in the field of face recognition is diffraction optical elements that reach submicron size.The problem of how to manufacture and produce micro and nano optical devices at low cost,high efficiency and high quality has not only attracted the attention of the scientific community,but also there is a huge demand in the industrial world.The rapid prototyping method proposed in this paper utilizes maskless lithography based on digital mirror devices(DMD)and photosensitive resins,which has a wide range of uses in three-dimensional(3D)printing.It realizes the fabrication of micro-structures with fast manufacturing speed,sub-micron accuracy and the smallest feature size of 1.5 ?m.To demonstrate the feasibility of this method,a Damman grating was fabricated to validate the technology.This article first explains the advantages and disadvantages of various micro and nano structure manufacturing technologies and the types and working principles of various micronano optical devices,and explains their importance to all sides.Based on this,the theory and design of DMD digital lithography,photosensitive resin and diffraction micro-optical devices are introduced in detail.After that,in order to achieve a higher-precision,higher-quality micro-structure and ensure efficient and fast manufacturing methods,this article starts with a series of experiments and optimized design based on the characteristics of photosensitive resin and the characteristics of digital lithography technology.The exposure dose of lithography is modulated to produce microstructures of appropriate height.Then through experiments,the resolution limit under this technology is explored and analyzed.After the resolution limit is determined,the determined minimum feature size is obtained to ensure that the smallest gap size and suitable structure are obtained during manufacturing.At the same time,the mask pattern has been redesigned and optimized to reduce the superimposed light intensity at the edges of the image and the shrinkage effect of the photosensitive resin to reduce manufacturing errors.Therefore,a Dammam grating having a diffraction efficiency of 50%was successfully generate,which can not only ensure accuracy but also maintain fast manufacturing speed.The successful fabrication of this Damman grating demonstrates the capabilities of photosensitive resins and DMD-based maskless digital lithography,proving that this can enable rapid and efficient fabrication of structures close to sub-microns.This will not only accelerate the scientific research process,but also become the basis for large-scale industrial production with micro or nano-structures.This work demonstrates the great potential of this method for the rapid,direct,and efficient fabrication of optical elements or structures at the nanoscale based on photosensitive resins.