Study On Diamond Fly-cutting Of Anti-reflection Microstructure On Optical Glass

Machining the anti-reflection structure on the optical glass,which can effectively reduce light reflection,improve transmission or diffraction efficiency,is an important way to improve the photoelectric conversion efficiency of the solar cell and the light-emitting efficiency of the organic light-emitting diode(OLED).However,it is extremely difficult to manufacture the antireflection microstructure on an optical glass substrate because of its high hardness and high brittleness.In the article the diamond fly cutting machining of the V-shaped micro-groove array is performed on the BK7 optical glass of the base material.Firstly,the V-shaped micro-groove array is optically designed.The mechanism of fly cutting is studied by fly cutting machining of single groove and then the machining parameters are optimized.Finally,the V-shaped microgroove array of the optical glass surface is fabricated and tested for optical properties.The main work of this paper is as follows:(1)Optical design of the V-shaped micro-groove array structureBased on the rigorous coupled wave method,the optical properties of the V-shaped microgroove array structure are simulated and analyzed.The influence of geometric parameters such as depth,width and duty ratio of the array on the anti-reflection performance is studied,which provides the optical design basis for anti-reflective structure machining.(2)Calculation of cutting thickness of diamond fly cuttingAccording to the actual section shape of the diamond fly cutting layer,the fly cutting thickness calculation model considering the tool arc radius is established.The change trend of cutting thickness at each point on the cutting edge is analyzed and the calculation formula of the maximum cutting thickness in a complete cutting cycle is derived.The theoretical calculation shows the functional relationships between the rotational speed,the feed rate,the cutting depth and the maximum thickness.(3)Diamond fly cutting machining of single groove on optical glass surfaceThrough machining test of single groove on the BK7 surface,the effects of rotation speed,the feed rate and the cutting depth on the machined surface quality are studied.We analyze the surface damage characteristics caused by tool tip wear under different cutting depths.The results show that the transverse crack caused by the tip of the cutting edge is more likely to extend to the micro-cracking on both sides of the surface forming groove,which destroys the surface integrity of the microstructure.(4)Fly cutting machining and optical performance test of anti-reflection array structureThe fly cutting machining of the anti-reflection array structure with different duty ratios is carried out to study the influence of the duty ratios on the structural integrity.Considering the influence of the duty ratios on the optical performance and the processability,the appropriate machining parameters are selected to prepare V-shaped micro-grooved array structure and perform optical performance tests.The optical test results of two-way scattering function show that the micro-grooves are beneficial to the anti-reflection of incident light at different angles.At the same time,the structure can be used for the light distribution design of the LED device,which achieves a reduction of 9° for the beam angle of the ultraviolet device with an emission wavelength of 365 nm and 395 nm.