数字电影滤光反射镜光谱设计

为了满足数字电影光学系统色温要求及提高光源能量利用效率,降低设计及光学薄膜镀制难度,计算了色温变化小、光源利用效率高的可见光高反射光谱波段。根据椭球滤光反射镜的工作原理及滤光薄膜的光谱特性,结合氙灯光源光谱及人眼的视觉函数,分析了可见光不同光谱波段对系统光效率及色度坐标的影响。获得了可见光波段光效利用率高,色度参数变化小的波段范围,解决了数字电影反光镜滤光薄膜可见光高反射波段初始设计问题。由滤光薄膜设计及镀制结果得到,405～690nm波长范围可作为数字电影滤光反射镜薄膜高反射区域,相比与氙灯光源光谱,x、y色度偏差不超过0.001,理论反射光光效率达99%以上。

A design of filtering reflector spectrum for digital cinema

In order to meet the color temperature,improve the efficiency of light energy in digital cinema system and reduce the difficulty for design and coating,the visible spectrum band with high efficiency and small changes in color temperature was calculated.According to the principle of ellipsoid reflector and the spectrum of thin film,together with the spectrum of xenon lamp and human visual function,the effects of different spectral bands on the optical efficiency and chromaticity coordinate of the thin film were analyzed.High light efficiency of visible spectrum and band range with slight change on chrominance parameter was obtained.Initial design of the reflector′s thin film with high reflection region on visible spectrum for digital cinema system was solved.According to optical thin film design and deposition calculation,the visible wavelength region between 405~690 nm could be used as a high reflection region on the reflector′s thin film for digital cinema system.In contrast with the spectrum of xenon light source,x,y chromaticity coordinate deviation is less than 0.001,and the theoretical reflection efficiency is higher than 99%.