【作者】 周万根；

【导师】 许忠保；

【作者基本信息】 湖北工业大学 ， 测试计量技术及仪器， 2012， 硕士

【摘要】 光学可变图像因具有绚丽的色彩、丰富多变的光学效果，作为光学防伪科技产品的重要手段，已被广泛应用于货币、签证、ID卡、绝密文件以及包装材料等物理载体上。随着技术的进步，激光防伪已从单纯的标志防伪发展到现在的整体型的综合性激光印刷包装防伪，光变图像作为新型的图像形式，使无油墨印刷成为可能，为包装印刷行业开创了新的局面。近年来，国内外制作光变图像的方法主要有两类：(1)点阵式直写技术，由两束激光在光刻胶上合束干涉形成光栅点，计算机控制二维精密平台对光刻胶板逐点曝光，形成具有浮雕结构位相型光栅像素，该方法对电子控制和机械扫描的准确度要求很高，而且制作效率比较低；(2)面阵式直写技术，由空间光调制器作为图形输入器件，采用逐面方式，制作效率比点阵式提高了几十倍，而且能获得高分辨率的图像，但是在同一位置曝光不同周期、转角的条纹，均需要旋转分束元件，即同一位置需要曝光多次。本文研究了以数字光栅模板形成光变图像的方法，搭建了以LCOS空间光调制器为图像发生器的光刻实验平台，该方法与上述两类方法相比有两大改进。首先，以LCOS为图像发生器，实现面阵式曝光；LCOS不仅作为图像发生器，同时也作为衍射元件，将LCOS变为数字光栅替代分束元件及机械旋转结构，可以得到高质量的具有位相信息的任意光斑图形。分析此方法分辨率能够达到每毫米1000线对，而且在分辨率范围内可以产生任意线宽的光斑，能够制作出高质量的光变图像。更多还原

【Abstract】 Optical variable device, which has showed its advantage in bringing gorgeouscolor and variational optical effect, is widely used in anti-counterfeiting as currency,ID card, wrapper and so on. With the development of technology, latest laseranti-counterfeiting not only produces simple security signs, but also makes monolithicintegrated laser printing packaging viable. As a novel form of image, optical variableimage can easily realize ink-free printing. Obviously, this will widely extend the fieldof the packaging-printing industry.In recent years, there are two major categories to facture optical variable deviceboth domestic and aboard:1) double beam laser with dot-by-dot exposure mode;2)surface matrix type lithography. The efficiency of surface matrix mode is higher thanthe dot matrix mode’s several times. But the both mode could not exposure differentcharacteristics grating in one time.The thesis studies and advances a new exposure mode to produce optical variableimages by using digital grating instead of traditional grating and its mechanical part.Designing a laser direct writing experiment system, in which LCOS is the imagegenerator. There are two improvements in this new method compared with thetraditional way, one is realizing planar array exposure by using LCOS to be imagegenerator, another is that the LCOS is not only works as image generator, but also theoptical diffractive element. As a result, the LCOS digital grating can get higherquality arbitrary spot pattern with phase information.By analyzing, resolution of the method could reach to1000lines per mm, and inthe whole resolution range could generate the spot of any line width we want,therefore higher quality optical variable image is accessible.更多还原