| 摘要 |
PURPOSE:To improve the light use efficiency, by arranging a beam splitting means where two or more holograms are superposed. CONSTITUTION:A hologram plate N1 consists of a transparent hologram substrate 2 and hologram materials 3 provided in a layer on this substrate 2, and an object color B and a reference light S are made incident to this hologram plate N1 at equal angles, and a required number of holograms are produced under the same condition. Hologram plates N2 and N3 produced in this manner are superposed. If respective diffraction efficiencies and transmission factors of holograms N2 and N3 are equal to each other, the overall intensity of the light in the diffraction direction is 2ab, and the overall intensity in the light transmission direction is a<2>+b<2>, and thus, when two hologram plates are used, the light use efficiency is higher than that for one hologram plate in case of a< 0.4. Similarly, three hologram plates can be used. |
