Depolarizing element, depolarizing device and image display device

摘要

PROBLEM TO BE SOLVED: To reduce generation of diffraction light in a depolarizing element in which a plurality of sub-wavelength structural areas having structural birefringence are two-dimensionally arrayed.SOLUTION: In a depolarizing element 1, a plurality of sub-wavelength structural areas 1a to 1h having structural birefringence are two-dimensionally arrayed in the mutually crossing X axis direction and Y axis direction. The sub-wavelength structural areas 1a to 1h have grooves arrayed repeatedly in periods each shorter than the wavelength of the light used, and the direction of the optical axis, which is the arrayed direction of the grooves, differ between adjoining sub-wavelength structural areas. The angle formed by the optical axis directions between the sub-wavelength structural areas adjoining in the X axis direction is not less than 45 degrees but not more than 90 degrees. The angle formed by the optical axis directions between the sub-wavelength structural areas adjoining in the Y axis direction is less than 45 degrees.SELECTED DRAWING: Figure 1