摘要 |
A light guiding plate unit which can emit uniform light of a predetermined polarization, a surface light source apparatus and a liquid crystal display apparatus are provided. A light guiding plate unit is provided with a light guiding plate which can guide light and has a first surface from which light is emitted and a diffraction grating which is provided on the first surface of the light guiding plate, and the diffraction grating is formed of a number of metal wires in straight lines which are aligned in a direction approximately perpendicular to the long axis of the metal wires, and the length w of the metal wires in the direction in which the number of metal wires are aligned is approximately 55% or more and approximately 85% or less of the spatial period of the diffraction grating. Thus, the ratio of the length w of the metal wires to the spatial period is set to 0.65 or higher and 0.85 or lower, and thus, it is possible to control the amount of transmission of light in a predetermined state of polarization through the diffraction grating formed on the first surface.
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