US 2013/0077141 A1 · OPTICAL DEVICE AND VIRTUAL IMAGE DISPLAY

Abstract

An optical device includes: a light guide plate receiving, for each of N types of wavelength bands, a plurality of parallel light beams with different incident angles each corresponding to view angles, and guiding the received parallel light beams; a first and a second volume hologram gratings of reflection type having a diffraction configuration which includes N types of interference fringes each corresponding to the N types of wavelength bands, and diffracting/reflecting the parallel light beams. The optical device satisfies for each wavelength band, a relationship of ‘P>L’, where ‘L’ represents a central diffraction wavelength in the first and second volume hologram gratings, defined for a parallel light beam corresponding to a central view angle, and ‘P’ represents a peak wavelength of the parallel light beams.

Claims1

Dependent claims

An optical device comprising:

a light source;
a light guide plate configured to receive light, and to guide the received light by total inner reflection;
a first hologram grating for diffracting the light entering the light guide plate;
and
a second hologram grating for diffracting light which has been propagated and reflected a plurality of times through the light guide plate,
wherein a peak wavelength of the light source is closer to a central diffraction wavelength of the light with a view angle which is diffracted a higher number of times in the second hologram grating than a central diffraction wavelength of the light with a view angle which is diffracted a lower number of times in the second hologram grating.

3 more elements

Dependencies are inferred from the claim text.

Optical device and virtual image display

Life of this patent

Optical device and virtual image display

Life of this patent

Abstract

Claims1