Polarization conversion element, method of manufacturing the same and illumination source unit using the same
AssigneeFujinon Corporation
InventorMasayuki Inamoto
Life of this patent
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Abstract
An polarization conversion device comprises a prismatic beam splitting assembly for separating p- and s-polarized polarized light orthogonal in the direction of polarization from a light source and a single sheet half-wave (λ/2) plate attached to an exit surface of the prismatic beam splitting assembly for changing one of the p- and s-polarized light 90° in the direction of polarization. The single sheet half-wave (λ/2) plate has a number of apertures arranged in a checked pattern and is prepared by die-cutting a single optical sheet using a pressing machine and adhered to the exit surface of the beam splitting assembly.
Claims3
In an polarization conversion device for bringing two beams of linear polarized light orthogonal in the direction of polarization into coincidence in the direction of polarization with each other, which comprises beam splitting means for separating beams incident upon available incidence areas of an incidence surface of the polarization conversion device into two beams of polarized light orthogonal in the direction of polarization and half-wave (λ/2) plate means defining said available incidence areas of the polarization conversion device for changing one of said two beam of liner polarized light 90° in the direction of polarization, the improvement comprising:
- said half-wave (λ/2) plate means consisting of a single sheet having apertures each of which opens a path of the other of said two beams of polarized light and which are arranged in a checked pattern so as thereby to form said incidence surface in a checked pattern where each adjacent rows of available incidence areas are shifted half a pitch at which said aperture are arranged in a row.
An illumination source unit for bringing two illumination beams of linear polarized light orthogonal in the direction of polarization into coincidence in the direction of polarization with each other, said illumination source unit comprising:
- beam splitting means for separating illumination beams incident upon available incidence area of an incidence surface of the polarization conversion device into two illumination beams of polarized light orthogonal in the direction of polarization;
- half-wave (λ/2) plate means for changing one of said two illumination beam of liner polarized light 90° in the direction of polarization, said half-wave (λ/2) plate means consisting of a single sheet which has a plurality of apertures for defining said available incidence areas of an incidence surface of the polarization conversion device, each said aperture opening a path of the other of said two illumination beams of polarized light and said apertures being arranged in a checked pattern so as thereby to form said available incidence surface in a checked pattern where each adjacent rows of available incidence areas are shifted half a pitch at which said aperture are arranged in a row;
- and
- a plurality of light source elements arranged in a pattern similar to said checked pattern of said available incidence areas of said incidence surface of said polarization conversion device.
A method of producing a polarization conversion device for bringing beams of linear polarized light orthogonal in the direction of polarization into coincidence in the direction of polarization with each other which comprises beam splitting means for separating beams incident upon available incidence areas of an incidence surface of the polarization conversion device into two beams of polarized light orthogonal in the direction of polarization and half-wave (λ/2) plate means for changing one of said two beam of liner polarized light 90° in the direction of polarization, the method producing a polarization conversion device comprising the steps of:
- preparing said beam splitting means;
- forming a plurality of apertures for defining said effective incidence areas of said incidence surface of the polarization conversion device in a single sheet of said half-wave (λ/2) plate means so that each said aperture opens a path of the other of said two illumination beams of polarized light and said apertures are arranged in a checked pattern so as thereby to form said available incidence areas in a checked pattern where each adjacent rows of available incidence areas are shifted half a pitch at which said aperture are arranged in a row;
- and
- attaching said a single sheet of said half-wave (λ/2) plate means to an exit surface of the polarization conversion device.
Dependencies are inferred from the claim text.