OPTICAL DEVICE, HEAD MOUNTED DISPLAY, ASSEMBLING METHOD FOR THE SAME, HOLOGRAPHIC DIFFRACTION GRATING, DISPLAY DEVICE, AND ALIGNMENT DEVICE

• US 20150260994A1
• Filed: 03/06/2015
• Published: 09/17/2015
• Est. Priority Date: 03/14/2014
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Akutsu, Katsuyuki, Nagasaka, Hideo, Kajio, Yusuke, Mizusawa, Takashi, Tokuyama, Kazutatsu, Tsukuda, Daisuke
• Granted Patent: US 11,073,693 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G02B 2027/0178 Eyeglass type eyeglass details G02C
• CPC Class Codes: G02B 2027/0198 System for aligning or maintaining alignment of an image in a predetermined direction
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 27/4205 having a diffractive optical element [DOE] contributing to image formation, e.g. whereby modulation transfer function MTF or optical aberrations are relevant
• 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 6/34 utilising prism or grating G02B6/293 takes precedence

Abstract

In some embodiments, a head mounted display is provided, comprising a light guide, at least first and second diffraction gratings, alignment marks A1 and B1 associated with the first diffraction grating, and alignment marks A2 and B2 associated with the second diffraction grating. The first diffraction grating may be disposed on a first surface of the light guide, the first surface facing away from a light input. The second diffraction grating may be disposed on a second surface of the light guide, the second surface facing towards the light input. The second diffraction grating may be adapted to diffract at least some of the light input into the light guide, and the first diffraction grating may be adapted to diffract at least some light transmitted through the light guide back into the light guide.

Claims

1. An optical device comprising:

a light guide comprising an input region and an output region, wherein the light guide is adapted to receive light at the input region and output at least some of the received light at the output region; and

at least first and second diffraction gratings, wherein;

the first diffraction grating is disposed on a first surface of the light guide, the first surface facing away from a light input,

the second diffraction grating is disposed on a second surface of the light guide, the second surface facing towards the light input,

the second diffraction grating is disposed at the input region of the light guide and adapted to diffract at least some of the light input into the light guide, and

the first diffraction grating is adapted to diffract at least some light transmitted through the light guide back into the light guide.

2. The optical device of claim 1, wherein the second diffraction grating is adapted to diffract and reflect at least some of the light input into the light guide to be propagated inside the light guide towards the output region.

3. The optical device of claim 2, wherein the first diffraction grating is disposed at the input region to diffract and reflect the at least some light transmitted through the light guide back into the light guide to be propagated inside the light guide towards the output region.

4. The optical device of claim 3, wherein the light input comprises first and second portions, the first and second portions having different angles of view, and wherein the second diffraction grating is adapted to let the first portion pass through but diffract and reflect the second portion.

5. The optical device of claim 4, wherein the second diffraction grating is adapted to let pass through the first portion of the light input, which is input at an angle away from the output region of the light guide, and to diffract and reflect the second portion of the light input, which is input at an angle towards the output region of the light guide.

6. The optical device of claim 1, further comprising at least one alignment mark formed of an interference fringe or a diffraction grating, the least one alignment mark being associated with at least the first diffraction grating or the second diffraction grating.

7. The optical device of claim 1, further comprising alignment marks A1 and B1 associated with the first diffraction grating and alignment marks A2 and B2 associated with the second diffraction grating.

8. The optical device of claim 7, wherein:

an angle θ

is formed by straight lines L1 and L2, the straight line L1 connecting the alignment marks A1 and B1 of the first diffraction grating, the straight line L2 connecting the alignment marks A2 and B2 of the first diffraction grating; and

the angle θ

is smaller than a selected angle threshold.

9. The optical device of claim 7, wherein the first diffraction grating comprises a first interference fringe, the first interference fringe being disposed between the alignment marks A1 and B1.

10. The optical device of claim 9, wherein the second diffraction grating comprises a second interference fringe, the second interference fringe being disposed between the alignment marks A2 and B2.

11. The optical device of claim 9, wherein the alignment mark A1 comprises a third interference fringe, the first and third interference fringes having an identical pattern.

12. The optical device of claim 11, wherein the alignment mark B1 comprises a fourth interference fringe, the first, third, and fourth interference fringes having the identical pattern.

13. The optical device of claim 8, wherein the selected angle threshold is 100 seconds.

14. The optical device of claim 8, wherein the selected angle threshold is selected so as to obtain an image contrast that is above a selected image contrast threshold.

15. The optical device of claim 14, wherein the selected image contrast threshold is 0.95.

16. The optical device of claim 1, further comprising alignment marks A1 and B1 associated with the first diffraction grating and alignment marks A2 and B2 associated with the second diffraction grating, wherein:

the alignment mark A1 does not overlap with the alignment mark A2; and

the alignment mark B1 does not overlap with the alignment mark B2.

17. The optical device of claim 16, wherein the alignment marks A1 and A2 are annular.

18. The optical device of claim 16, wherein a radius of the alignment mark A1 is larger than a radius of the alignment mark A2.

19. The optical device of claim 6, further comprising a third diffraction grating disposed at the output region of the light guide and adapted to diffract at least some of the light diffracted by the first diffraction grating and the second diffraction grating.

20. A head mounted display comprising:

a light guide comprising an input region and an output region, wherein the light guide is adapted to receive light at the input region and output at least some of the received light at the output region;

at least first and second diffraction gratings, wherein;

the first diffraction grating is disposed on a first surface of the light guide, the first surface facing away from a light input,

the second diffraction grating is disposed on a second surface of the light guide, the second surface facing towards the light input,

the second diffraction grating is disposed at the input region of the light guide and adapted to diffract and reflect at least some of the light input into the light guide to be propagated inside the light guide towards the output region, and

the first diffraction grating is adapted to diffract and reflect at least some light transmitted through the light guide back into the light guide;

alignment marks A1 and B1 associated with the first diffraction grating; and

alignment marks A2 and B2 associated with the second diffraction grating.

21. The head mounted display of claim 20, wherein:

an angle θ

is formed by straight lines L1 and L2, the straight line L1 connecting the alignment marks A1 and B1 of the first diffraction grating, the straight line L2 connecting the alignment marks A2 and B2 of the first diffraction grating; and

the angle θ

is smaller than a selected angle threshold.

22. The head mounted display of claim 20, wherein:

the alignment mark A1 does not overlap with the alignment mark A2; and

the alignment mark B1 does not overlap with the alignment mark B2.

23. A head mounted display comprising:

a light guide;

at least first and second diffraction gratings, wherein;

the first diffraction grating is disposed on a first surface of the light guide, the first surface facing away from a light input,

the second diffraction grating is disposed on a second surface of the light guide, the second surface facing towards the light input,

the second diffraction grating is adapted to diffract and reflect at least some of the light input into the light guide to be propagated inside the light, and

the first diffraction grating is adapted to diffract and reflect at least some light transmitted through the light guide back into the light guide;

alignment marks A1 and B1 associated with the first diffraction grating; and

alignment marks A2 and B2 associated with the second diffraction grating.

24. The head mounted display of claim 23, wherein:

the light guide comprises an input region and an output region;

the light guide is adapted to receive light at the input region and output at least some of the received light at the output region; and

the first diffraction grating is disposed at the input region to diffract and reflect the at least some light transmitted through the light guide back into the light guide to be propagated inside the light guide towards the output region.