摘要 |
PURPOSE:To embody a direct viewing type image display device having a high contrast by combination with a liquid crystal device. CONSTITUTION:This optical element is used for forming dot patterns of three colors for color image display as spot groups and is composed of a light source 3, a transparent substrate 2 and a volume phase type hologram 1 formed on the substrate 2. The hologram 1 is recorded with multiple element holograms having functions to spatially separate light beams of respective colors and the light beams of the respective colors included in the light source are spatially separated by the hologram 1, by which the three color light spot groups R, G, B arranged like a mosaic are formed. Then, the hologram 1 is not reconstructed by the light entering from the outer side (air side) of the hologram 1 and, therefore, the hologram is apparently transparent. Since the dot patterns of the respective colors are respectively independently formed, the bright dot patterns of three colors are formed on the display. |