Research Of The Rainbow Holographic Miniature Engraving Technology Based On Digital Micro-mirror Device

The miniature art is a treasure of world civilization in the history of art, the art have rich content and high artistic value. There is wide variety of the world’s traditional miniature works of art; they are beautifully carved, detailed and rich colors. But the vast majority of these miniature works of art are hand carved, the tiny structures of these miniature works of art bring a great challenge to artists, and complete a miniature works of art often takes a very long period of time. Most of the miniature work of art can easily fade, because of the materials and the pigment of the miniature works of art. Therefore, there may be vast artistic and commercial value, if can produce a miniature works of art which is not corroded in thousand of years and not fade easily.In this paper, to study and explore the rainbow holographic miniature craft by methods of optical holography using digital micro-mirror device (DMD). The rainbow effect replaces the role of the pigment, making the miniature works have color effect. Minifying the graphic all at once, the production period of time have been shortened adequately and the problem of image distortion have been solved. Two programs have been proposed for this research. The first program is the spectrum interferometry. Using the grating feature of DMD, after the Fourier transform of the imaging lens, the spectrum is superposing in the image plane. By this program, to make rainbow miniature hologram, do not need slit and reference light, in the Tianj in-type I holographic plate and BP-218positive photoresist in the coherent light or incoherent light. The second program is the use of digital lithography. Designing many repetitive units in the picture by graphic design software CorelDraw to simulate the interference fringe of which is the result of the object light and reference light interfere. Then, the picture displayed on the DMD, forming a miniature rainbow hologram in the photoresist by the minified projection lens. With white light source illuminating, could see the obvious rainbow. Via the second program, can not only acquire the miniature rainbow hologram in the photoresist, but also need not to build the complex record optical path on the holographic platform, only using a single light of UV source. It is simple to make a rainbow hologram.To using Chrome glass and stainless steel substrate, by the method of wet etching and electrochemical etching, the miniature rainbow hologram in the photoresist transfer to the Chrome glass and stainless steel substrate, to achieve the purpose of permanent preservation of the rainbow hologram miniature figure.