IMAGE DISPLAY DEVICE

摘要

Provided is an image display device, including: an image projection optical system projecting, at infinity, image light corresponding to an arbitrary image; a first light guide portion formed like a plate having a first plane and a second plane, in which the image light projected from the image projection optical system is transmitted in part through the first plane with the rest being reflected between the first plane and the second plane, so as to be propagated in the x-direction by repeating the transmission and the reflection; a first spacer plate formed like a plate having a third plane and a fourth plane, the third plane being bonded to the first plane; and a first output deflector formed on or bonded to the fourth plane, the first output deflector diffracting part of the image light transmitted through the first plane, in a direction substantially perpendicular to the first plane.

主权项

1. An image display device comprising:
an image projection optical system projecting, at infinity, image light corresponding to an arbitrary image; a first light guide portion formed like a plate having a first plane and a second plane parallel and opposing to each other, in which the image light projected from the image projection optical system is transmitted in part through the first plane with the rest being reflected between the first plane and the second plane, so as to be propagated in an x-direction perpendicular to an optical axis direction of the image projection optical system by repeating a transmission and a reflection; a first spacer plate formed like a plate having a third plane and a fourth plane parallel and opposing to each other, the third plane being bonded to the first plane; and a first output deflector formed on or bonded to the fourth plane, the first output deflector diffracting part of the image light transmitted through the first plane, in a direction substantially perpendicular to the first plane, the first output deflector comprising a reflective diffraction plane, and satisfying the following expression 1:nw1cosθc1tanθc1(1-2t1ns1λcosθc1+2t1ns1)≤0.0006[Expression1] where θc1 is a propagation angle of the image light in the first spacer plate in which the first output deflector diffracts the image light perpendicularly to the fourth plane, t1 is a thickness of the first spacer plate, λ is a wavelength of the image light, ns1 is a refractive index of the first spacer plate, and nw1 is a refractive index of the first light guide portion.