Research On The Flatness Technology Of The Super Smooth Optical Surface

Super smooth surface have the necessary application in optics, microelectronics, energy and other fields and then become the focus of the precision machining technology. In the optical field, super smooth surface is a necessary condition for reducing optical scattering and improving induced damage threshold.However,the key technology of ion beam etching polishing is the flatness of the super smooth optical surface technology to prepare super smooth optical surface.The paper mainly introduces the zinc sulfide crystal (ZnS) and potassium dihydrogen phosphate crystal (KDP) administered as basal material to research optical surface smooth technology.The main content includes the characteristics,application and processing technology of the super smooth optical surface. A lot of experiments were done to study how to achieve the flattening layers for lower roughness.A complete process routes were summed up and process parameters was given. The main conclusions are as follows.1) Coating PI1-1500 on the surface of ZnS crystal by using the Spin-Coating method at the slow revolving speed of 600r·min-1 and at the high revolving speed of 5000r·min-1, solidifying for 30 minutes at the temperature of 150℃, refluxing 10 to 20 minutes at the temperature of 190℃ by using the Heat-Reflux method, refluxing 40 to 60 minutes at the circulatory gas flow of 200ml/min by using the gas-phase refluxing device, eventually, a flattening layer with low roughness and less surface defects was obtained. The roughness of layer is below 1.2nm on ZnS crystal surface. By using the steps as previously mentioned, a flattening layer with a roughness below 1.1 nm expect by using PI 1-700 was obtained, at the high revolving speed of 3000r·min-1, refluxing 45 minutes at the circulatory gas flow of 500ml/min.2) Coating PI1-1500 on the surface of KDP crystal by using the Spin-Coating method at the slow revolving speed of 600r·min-1 and at the high revolving speed of 2000rmin-1 or 4000r·min-1, solidifying for 4 hours at the temperature of 80℃, using the same gas-phase refluxing device, eventually, a flattening layer with a average roughness about 1.25nm was receive. It is produced by using the same steps expect PI 1-700 replacing PI1-1500 at the high revolving speed of 5000r·min-1.