REFRACTIVE INDEX MODULATED DIFFRACTION-TYPE OPTICAL ELEMENT AND PROJECTOR INCLUDING THE SAME

PROBLEM TO BE SOLVED: To provide a diffractive optical element capable of uniformizing the distribution of optical intensity on a specified irradiation surface, to which an optical beam from a light source is applied in a projector, conveniently and at a low cost. SOLUTION: The refractive index modulated diffractive optical element comprises a DLC (translucent diamond-like carbon) film formed on a translucent substrate, and the refractive index of the DLC film is modulated, to include a plurality of regions having relatively high refractive indexes and a plurality of regions, having relatively low refractive indexes therein so as to produce light diffraction. The refractive index modulation generates diffraction action so that the distribution of the intensity on the cross-section of an optical beam made incident on the DLC film is converted into the distribution of uniform intensity on the specified irradiation surface. COPYRIGHT: (C)2006,JPO&NCIPI