Optical device, and virtual image display

• US 9,176,265 B2
• Filed: 02/04/2013
• Issued: 11/03/2015
• Est. Priority Date: 03/29/2004
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Mukawa, Hiroshi, Akutsu, Katsuyuki
• Primary Examiner(s): Lepisto, Ryan
• Assistant Examiner(s): ANDERSON, GUY G
• Application Number:
  US13/758,767
• Publication Number:
  US 20130155513A1
• Time in Patent Office: 1,002 Days
• Field of Search: 385/15, 385/31, 385/37, 385129-131, 359 15- 19, 359 31- 34, 349/11
• US Class Current: 1/1
• CPC Class Codes: G02B 13/18 with lenses having one or more non-spherical faces, e.g. for reducing geometrical aberration G02B13/002 takes precedence
• CPC Class Codes: G02B 17/004 Systems comprising a plurality of reflections between two or more surfaces, e.g. cells, resonators multipass arrangements for optical cuvettes G01N21/031; laser resonators H01S3/05
• CPC Class Codes: G02B 17/006 Systems in which light light is reflected on a plurality of parallel surfaces, e.g. louvre mirrors, total internal reflection [TIR] lenses Fresnel mirrors G02B5/09, Fresnel lenses G02B3/08
• CPC Class Codes: G02B 17/0856 comprising a refractive element with a reflective surface, the reflection taking place inside the element, e.g. Mangin mirrors
• CPC Class Codes: G02B 2027/0116 comprising devices for correcting chromatic aberration
• CPC Class Codes: G02B 2027/0118 comprising devices for improving the contrast of the display / brillance control visibility
• CPC Class Codes: G02B 2027/0125 Field-of-view increase by wavefront division
• CPC Class Codes: G02B 2027/0174 holographic
• CPC Class Codes: G02B 27/0081 with means for altering, e.g. enlarging, the entrance or exit pupil
• CPC Class Codes: G02B 27/01 Head-up displays
• CPC Class Codes: G02B 27/0103 comprising holographic elements
• CPC Class Codes: G02B 27/017 Head mounted
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 27/144 using partially transparent surfaces without spectral selectivity G02B27/147 takes precedence
• CPC Class Codes: G02B 27/4272 having plural diffractive elements positioned sequentially along the optical path
• CPC Class Codes: G02B 5/18 Diffraction gratings holographic optical elements G02B5/32, G03H; integrally combined with optical fibres G02B6/02057; for coupling light guides G02B6/34; integrally combined with optical integrated light guides G02B6/12; grating systems G02B27/44
• CPC Class Codes: G02B 5/1842 Gratings for image generation G02B5/1847 takes precedence
• CPC Class Codes: G02B 6/00 Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
• CPC Class Codes: G02B 6/0026 Wavelength selective element, sheet or layer, e.g. filter or grating
• CPC Class Codes: G02B 6/0033 Means for improving the coupling-out of light from the light guide
• CPC Class Codes: G02B 6/005 : provided by one optical element, or plurality thereof, placed on the light output side of the light guide
• CPC Class Codes: G02B 6/2848 : having refractive means, e.g. imaging elements between light guides as splitting, branching and/or combining devices, e.g. lenses, holograms
• CPC Class Codes: G02B 6/43 : Arrangements comprising a plurality of opto-electronic elements and associated optical interconnections

Abstract

A virtual image display device with an optical waveguide to guide, by internal total reflection, parallel pencil groups meeting a condition of internal total reflection, a first reflection volume hologram grating to diffract and reflect the parallel pencil groups incident upon the optical waveguide from outside and traveling in different directions as they are so as to meet the condition of internal total reflection inside the optical waveguide and a second reflection volume hologram grating to project the parallel pencil groups guided by internal total reflection inside the optical waveguide as they are from the optical waveguide by diffraction and reflection thereof so as to depart from the condition of internal total reflection inside the optical waveguide.

Claims

1. An image display device comprising:

an image display element;

an optical system;

an optical waveguide having a light incident port along a first portion of the optical waveguide and a light outgoing port along a second portion of the optical waveguide, the optical waveguide configured to (a) receive light from the image display element through the light incident port via the optical system and (b) provide the light as output through the light outgoing port;

a first diffraction grating positioned along the first portion of the optical waveguide;

a second diffraction grating positioned along the second portion of the optical waveguide;

a light shield configured to prevent leakage of the light through the first diffraction grating; and

a transparent substrate having oppositely facing first and second surfaces, the first surface facing both the light incident port and the light outgoing port, the second surface facing the light shield,

wherein,

the first portion and the second portion are at different positions along the optical waveguide, and

the first diffraction grating is between the light incident port of the optical waveguide and the light shield.

2. The image display device according to claim 1, further comprising:

an air space (i) in-between a surface of the optical waveguide and the transparent substrate, and (ii) located on a side of the optical waveguide where the first diffraction grating and the second are not present on the optical waveguide,

wherein the transparent substrate is located on another side of the optical waveguide where the first diffraction grating and the second diffraction grating are present.

3. The image display device according to claim 1, wherein the optical waveguide is configured to reflect a portion of the light guided through the optical waveguide a different number of times in the optical waveguide.

4. The image display device according to claim 1, wherein the first diffraction grating or the second diffraction grating or both the first and second diffraction gratings have a plurality of interference fringes.

5. The image display device according to claim 1, wherein the first diffraction grating, the second diffraction grating, or both the first diffraction grating and the second diffraction grating have layers stacked together, each of the first and second diffraction gratings having an interference fringe.

6. The image display device according to claim 1, wherein an area of the second diffraction grating is larger than an area of the first diffraction grating.

7. The image display device according to claim 1, wherein interference fringes of the first and second diffraction grating are recorded with the same pitch.

9. The image display device according to claim 1, wherein the light shield is wider than the first diffraction grating.

10. The image display device according to claim 1, wherein an edge of the light shield is between the first diffraction grating and the second diffraction grating.

11. The image display device according to claim 1, wherein the light shield and the second diffraction grating are non-overlapping.

12. The image display device according to claim 1, wherein the light shield is disposed at a side of the transparent substrate where the first diffraction grating is not present.

17. The image display device according to claim 1, wherein the optical system is a collimating optical system that receives a plurality of pencils from the image display element and forms parallel pencil groups different in angle of field from each other.

8. A head mounted display system comprising:

an image display element;

an optical system;

an optical waveguide having a light incident port along a first portion of the optical waveguide and a light outgoing port along a second portion of the optical waveguide, the optical waveguide configured to (a) receive light from the image display element via the optical system and (b) provide the light as output through the light outgoing port;

a first diffraction grating positioned along the first portion of the optical waveguide;

a second diffraction grating positioned along the second portion of the optical waveguide;

a light-shield configured to prevent leakage of the light through the first diffraction grating; and

a transparent substrate having oppositely facing first and second surfaces, the first surface facing both the light incident port and the light outgoing port, the second surface facing the light shield,

wherein,

the first portion and the second portion are at different positions along the optical waveguide, and

the first diffraction grating is between the light incident port of the optical waveguide and the light shield.

13. The head mounted display system according to claim 8, wherein the light shield is wider than the first diffraction grating.

14. The head mounted display system according to claim 8, wherein an edge of the light shield is between the first diffraction grating and the second diffraction grating.

15. The head mounted display system according to claim 8, wherein the light shield and the second diffraction grating are non-overlapping.

16. The head mounted display system according to claim 8, wherein the light shield is disposed at a side of the transparent substrate where the first diffraction grating is not present.

18. The head mounted display system according to claim 8, wherein the optical system is a collimating optical system that receives a plurality of pencils from the image display element and forms parallel pencil groups different in angle of field from each other.