| 摘要 |
PURPOSE:To provide the display device which has a long battery life and is reduced in the cost and complicity of production without using color filters by providing a spacial optical modulation element and diffraction means. CONSTITUTION:A light source 6 and a lens 7 supply collimated beams of light with which a grating 4 is irradiated at about 45 deg. with the normal thereof. The respective diffraction grating elements 5 separate the primary colors irradiated to the red, green and blue pixels of a liquid crystal layer 1 and, therefore, the elements 5 which are the same as each other have the diffraction gratings which are chirped, i.e., are changed in grating pitch over the entire part of the grating. The conventional color filters are omitted by using the diffraction means for dividing the multicolor light rays to 2 or more colors and, therefore, the light rays utilizable from the back illumination are further efficiently used. The use of a smaller battery is made possible as the power source for back illuminating by the diffraction means having relatively high efficiency and/or the battery life is increased. |
