Technological Research Of The Scattered Light Measurement Of Optical Element Of The Surface In Solar Telescope System

The scattered light will degrade the image quality of optical system. Imaging contrast of optical system and the image sharpness will decrease due to the scattered light, severely scattering noise completely submerging target signal.Especially for solar observation optical system, due to the large sunlight intensity,imaging contrast surface of the sun is low,even relatively weak scattered light also will have a significant impact on system performance.Thus, the scattered light has become an important obstacle restricting performance of Solar Optical imaging system.In this paper, measurement technology of the scattered light of solar telescope optical surface of the parts will be studied.Firstly, the scattered light of basic theory and research methods will be considered in this article.introducing the basic theory of the scattered light, mainly including bidirectional reflection distribution function theory and total integral scattering theory.Then introducing the method of measuring scattered light, mainly include BRDF method and TIS method.Then briefly introducing the measuring device of TIS method used in this paper, according to the final comparison of different measurement principles and methods of this paper to illustrate the reasons why the measurement of scattered light using TIS method.Secondly, the article analyzes theory of the integrating sphere,modeling and analyzing entity of integrating sphere.Derivation of the relationship among the exit illumination of the integrating sphere and spectral reflection of inner wall of the integrating sphere,overall spectral radiation flux of which is into the integrating sphere,radius of the inner ball of the integrating sphere,and the ratio relationship between the total opening area of the integrating sphere and all internal reflection surface area of the sphere(including the opening area).In the case of the existing entity integrating sphere, integrating sphere was modeled with the software named SolidWorks,and imported into TracePro to do simulation.According to the material properties of the material in TracePro’s database,the reliability of the integrating sphere model is verified and experiment of light beam radius is simulated.Thirdly, building a self-made measurement instrument of total integral scattering. To build the instrument of total integrated scattering which is in the core of the integrating sphere, including an integrating sphere, the semiconductor light source and power meter.Conducting experiment in the use of semiconductor laser light source of 650 nm.The comparison between measured result obtained by self-made scattering and measured results obtained with the Hannover Laser Centre production of 633 nm,which verify self-made total integrated scattering instrument reliability.Whether the uncertainty of self-made total integrated scattering measurements can achieve the desired goals, and the reasons causing the differences in the experiment result between the self-made total integrated scattering and the German-made instrument for are analyzed.Fourthly,experiment verifies the theory of total integrated scattering.Conducting experimental verification to the relationship between the total integral scattering theory in inverse proportion to the square of the wavelength of the value of TIS. Use self-made total integrated scattering instrument conducting experiments with three wavelengths(650nm, 520 nm and 450nm) semiconductor light sources.data of the red light of 650 nm and the blue light of 450 nm are numerically fitted.Take measurement results of the green light of 520 nm substituted into the obtain numerical formula, if they meet fitted, we can verify the relationship between the wavelength and the TIS value.we can get wavelength distribution of TIS value based on the total integral scattering theory and take the experimental data into the verification of their rationality.Finally,introducing the blackbody radiation theory and deducing TIS total value of the visible spectrum range of the sun. Planck’s blackbody radiation theory and formulas are introduced and analyzed.Conduct the simulation to analysis relationships of the black body radiation energy density curve with the wavelength and color temperature.Analyze the relationship between changes of size and position of radiation energy density curve peak and color temperature.Finally according to the blackbody radiation energy density values of determined target relationship and numerical relationship between TIS values with wavelength, we can get light scattering of visible light wavelength components the size of the share of each,TIS value of each wavelength component and the size of total scattered light of blackbody target(sun).