ILLUMINATION SYSTEM FOR HARD COPY APPARATUS

摘要

An illumination system (10,30,100,130,150,180,200) for hard copy applications including an elongated array (32) of light emitting elements (34) i n combination with a light mixing element (42,46) for mixing the light from the individual elements in the lateral or cross-process direction. A curved array (32) or linear array (102) of light emitting elements with an aspheric lens (108 ) may be utilized, with a cylindrical lens (36,106) compressing the beam of light in the vertical or process direction. The light mixing elements (42,46) are preferably comprised of holographic diffusers. Sufficient mixing of the light from the array is achieved in the cross-process direction whereby a reduction in light output of one light emitting element does not generate a significant localized reduction in intensity at the elongated spatial light modulator. Preferably, the spatial light modulator is a digital micromirror device (DMD), but may also comprise of other devices including those of the transmissive type, including liquid crystal devices.