Abstract: Disclosed herein is a backlight unit which has high utilization efficiency over the entire visible wavelength band. The backlight unit includes a reflective polarization splitter to allow a light of a surface light source to emit therethrough. The reflective polarization splitter includes a plurality of wires arranged in a wire grid shape. With this structure, when light of the surface light source passes through the wires, the wires passes only a certain polarized light, for example, s-polarized light having a vibration plane vertical to a longitudinal direction of the lattice wires therethrough, while reflecting other polarized components of the light according to the reflection coefficient of the wires.

Abstract: A polarizing optical device has first and second major surfaces. The polarizing optical device is provided at the first major surface thereof with extrafine structures made of a metal and arranged in a specific direction. The extrafine metal structures are provided at surfaces thereof with a metal compound part, the metal compound part being formed by performing surface treatment on the surfaces of the extrafine metal structures. When light is incident from the first major surface side, light polarized in a direction parallel to the specific direction is absorbed, and light polarized in a direction perpendicular to the specific direction is transmitted. When light is incident from the second major surface side, light polarized in the direction parallel to the specific direction is reflected, and light polarized in the direction perpendicular to the specific direction is transmitted.

Abstract: A planar light source device having excellent in-plane uniformity of brightness includes an illuminator having an array of light sources, a light transmission plate in an optical path of light output by the illuminator, and a plurality of refractive diffusing elements on the light transmission plate, each refractive diffusing element providing more than two refractive surfaces in at least one vertical cross-section along the optical path at an angle determined in accordance with a pattern of the array of light sources. Each refractive diffusing element may be a polygonal prism or a microlens.

Abstract: A polarizing optical device has first and second major surfaces. The polarizing optical device is provided at the first major surface thereof with extrafine structures made of a metal and arranged in a specific direction. The extrafine metal structures are provided at surfaces thereof with a metal compound part, the metal compound part being formed by performing surface treatment on the surfaces of the extrafine metal structures. When light is incident from the first major surface side, light polarized in a direction parallel to the specific direction is absorbed, and light polarized in a direction perpendicular to the specific direction is transmitted. When light is incident from the second major surface side, light polarized in the direction parallel to the specific direction is reflected, and light polarized in the direction perpendicular to the specific direction is transmitted.

Abstract: A planar light source device having excellent in-plane uniformity of brightness includes an illuminator having an array of light sources, a light transmission plate in an optical path of light output by the illuminator, and a plurality of refractive diffusing elements on the light transmission plate, each refractive diffusing element providing more than two refractive surfaces in at least one vertical cross-section along the optical path at an angle determined in accordance with a pattern of the array of light sources. Each refractive diffusing element may be a polygonal prism or a microlens.

Abstract: Disclosed herein is a backlight unit which has high utilization efficiency over the entire visible wavelength band. The backlight unit includes a reflective polarization splitter to allow a light of a surface light source to emit therethrough. The reflective polarization splitter includes a plurality of wires arranged in a wire grid shape. With this structure, when light of the surface light source passes through the wires, the wires passes only a certain polarized light, for example, s-polarized light having a vibration plane vertical to a longitudinal direction of the lattice wires therethrough, while reflecting other polarized components of the light according to the reflection coefficient of the wires.