| 摘要 |
PURPOSE:To satisfactorily bring an incident light having an arbitrary polarized light component to an optical modulation, by enclosing a refractive index variable substance into a groove part of a phase type diffraction grating, providing plural groove parts thereof, and also, forming them so that the groove direction is varied continuously. CONSTITUTION:Transparent electrodes 3, 3 are provided so as to come into contact with two pieces of transparent substrates 4, 4. Between its transparent electrodes 3, 3, a phase type diffraction grating 2 is provided, and its diffraction grating 2 is formed to plural waveforms. In accordance therewith, a groove part 1 (shown by oblique lines) of the diffraction grating 2 becomes plural pieces of independent waveform shapes, and formed so that the groove direction is varied continuously. By enclosing a refractive index variable substance (liquid crystal) 2 into its groove part 1, an optical modulation element is constituted. Also, by making length L of the groove part 1 longer than width W, the liquid crystal 2 is brought to a horizontal orientation in the lengthwise direction of the groove part. Accordingly, since the groove part is formed as the foregoing, even if height of the diffraction grating is decreased, light having an arbitrary polarized light characteristic can be modulated, and the liquid crystal can be brought satisfactorily to a horizontal orientation.
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