WIDE ANGLE AND HIGH RESOLUTION TILED HEAD-MOUNTED DISPLAY DEVICE

• US 20130187836A1
• Filed: 04/30/2010
• Published: 07/25/2013
• Est. Priority Date: 04/30/2010
• Status: Active Grant

• Current Assignee: Beijing Institute of Technology, Arizona Board of Regents (University of Arizona)
• Original Assignee: Beijing Institute of Technology, Arizona Board of Regents (University of Arizona)
• Inventors: Cheng, Dewen, Wang, Yongtian, Hua, Hong
• Granted Patent: US 9,244,277 B2
• Time in Patent Office: Days
• US Class Current: 345/8
• CPC Class Codes: G02B 2027/011 comprising device for correcting geometrical aberrations, distortion
• CPC Class Codes: G02B 2027/0123 comprising devices increasing the field of view
• CPC Class Codes: G02B 2027/0147 comprising a device modifying the resolution of the displayed image
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 5/04 Prisms

Abstract

A tiled head-mounted display device comprises an optical component including a plurality of prisms with free-form surfaces, and a display component including a plurality of micro-displays (6), wherein the number of the micro-displays (6) and the number of the prisms with free-form surfaces is identical, and each prism with free-form surfaces and the corresponding micro-display (6) constitute a display channel. Each prism is a wedge prism including a first surface (2), a second surface (3) and a third surface (4). The exit pupil planes of each display channel are coincident, thus avoiding pupil aberration and keeping exit pupil diameter and eye clearance same as a single ocular. There is no resolution variance throughout the entire field of view, thus preventing extra trapezoid distortion. The tiled head-mounted display device is compact and lightweight, and provides wide field of view and high resolution. The tiled head-mounted display device can be readily applicable to augmented environments applications by simply adding an auxiliary free-form lens behind the prism with free-form surfaces.

Claims

1. A tiled head-mounted display device, comprising:

an optical component including a plurality of prisms with free-form surfaces, each prism being a wedge prism comprising a first optical surface, a second optical surface and a third optical surface; and

a display component including a plurality of micro-displays, wherein the number of the micro-displays and the number of the prisms with free-form surfaces is identical,

wherein each prism with free-form surfaces and the corresponding micro-display constitutes a display channel, a coordinate system is defined as;

global coordinate origin O is exit pupil center;

Z-axis is in a direction along the viewing axis of user'"'"'s eye;

Y-axis is perpendicular to Z-axis and extends right above the eye;

X-axis is perpendicular to both Y-axis and Z-axis, constituting a Cartesian coordinate;

wherein the display channels are tiled so that an overall field of view of the tiled device can be substantially a summation of individual field of view of each display channel and the center of exit pupil of each display channel in the tiled device is located at a pupil center of the user'"'"'s eye.

2. The tiled head-mounted display device of claim 1, wherein the prism (101) comprises a first optical surface (2), a second optical surface (3) and a third optical surface (4) in a counter-clockwise order relative to X-axis, and the first optical surface (2) and the second optical surface (3) are free-form surfaces, the third optical surface (4) is selected from free-form, spherical or non-spherical surface, the first optical surface (2) is a transmissive surface, the second optical surface (3) is a concave reflective surface or semi- transmissive and semi-reflective surface, and the third optical surface (4) is a transmissive surface.

3. The tiled head-mounted display device of claim 1, wherein the display channels are tiled by optical tiling methods, the first optical surface (2), the second optical surface (3) and the third optical surface (4) of each prism (102) satisfy following conditions (1)-(3):

18≦

Z_Pd≦

28  

 

(1)

1.5≦

Z_Pd′

−

Z_Pd≦

3  

 

(2)

Z_Pd≧

the eye clearance distance, i.e., 15  

 

(3)

where, P_c is an intersection point of R_u with the first optical surface (2) upon total reflection, P_d is an intersection point of chief ray R_c in horizontal field of view with the first optical surface (2), P_d is an intersection point of R_c with the second optical surface (3),

wherein optical tiling methods comprise a first optical tiling method and a second optical tiling method,

wherein in the first optical tiling method, the bottom surfaces (11) of both prisms to be tiled are directly cemented together, the bottom surface (11) of each prism is positioned between the first optical surface (2) and the second optical surface (3);

wherein in the second optical tiling method, the side surfaces (22, 23) of the respective prisms are directly cemented, the side surface of each prism intersects with the first optical surface (2), the second optical surface (3) and the third optical surface of the prism (4).

4. The tiled head-mounted display device of claim 2, wherein a material used in the prism (101;

102) with free-form surfaces has a refractive index N_d1 of 1.4<

N_d1<

1.8 and a Abbe numberV_d1 above 20.

5. The tiled head-mounted display device of claim 2, wherein the prism (101;

102) with free-form surfaces has a first order focal length f of 14<

f<

27 mm.

6. The tiled head-mounted display device of claim 2, wherein the head-mounted display device comprises a first display channel and a second display channel tiled by the first mechanical tiling method, the first display channel is rotated by a first angle in YOZ plane about X-axis of a global coordinate system, the second display channel is rotated by ±

180°

about Z axis which is in a direction along viewing axis of a human eye, and then rotated by the first angle in the opposite direction about X-axis of the global coordinate system.

7. The tiled head-mounted display device of claim 6, wherein the tiled head-mounted display has a horizontal field of view of at least 50°

and a vertical field of view of at least 40°

.

8. The tiled head-mounted display device of claim 2, wherein the head-mounted display device comprises a first display channel and a second display channel tiled by the second mechanical tiling method, the first display channel is rotated by a second angle in XOZ plane about Y-axis of a global coordinate system, the second display channel is rotated by the second angle in the opposite direction about Y-axis of the global coordinate system.

9. The tiled head-mounted display device of claim 8, wherein the tiled head-mounted display has a horizontal field of view of at least 70°

and a vertical field of view of at least 30°

.

10. The tiled head-mounted display device of claim 2, wherein the head-mounted display device comprises a first display channel, a second display channel and a third display channel rotated about Y-axis of a global coordinate system by a predetermined angle, the second display channel is tiled with the first display channel and the third display channel using second mechanical tiling method, respectively.

11. The tiled head-mounted display device of claim 10, wherein the tiled head-mounted display has a horizontal field of view of at least 100°

and a vertical field of view of at least 30°

.

12. The tiled head-mounted display device of claim 2, wherein the head-mounted display device comprises a first display channel, a second display channel, a third display channel and a fourth display channel rotated about Y-axis of the global coordinate system by a predetermined angle, the second display channel is tiled with the first display channel and the third display channel with the second mechanical tiling method, respectively, the third display channel is tiled with the second display channel and the fourth display channel using the second mechanical tiling method, respectively.

13. The tiled head-mounted display device of claim 12, wherein the tiled head-mounted display has a horizontal field of view of at least 120°

and a vertical field of view of at least 30°

.

14. The tiled head-mounted display device of claim 2, wherein the head-mounted display device comprises a first display channel, a second display channel, a third display channel and a fourth display channel, the first display channel and the third display channel are rotated by a second angle in XOZ plane about Y-axis of a global coordinate system, the second display channel and the fourth display channel are rotated by the second angle in the opposite direction about Y-axis of the global coordinate system, the first display channel and the second display channel are tiled with the second mechanical tiling method, the third display channel and the fourth display channel are tiled with the second mechanical tiling method, the first display channel and the third display channel are tiled with the first mechanical tiling method, and the second display channel and the fourth display channel are tiled with the first mechanical tiling method.

15. The tiled head-mounted display device of claim 14, the tiled head-mounted display has a horizontal field of view of at least 70°

and a vertical field of view of at least 50°

.

16. The tiled head-mounted display device of claim 2, wherein the head-mounted display device comprises a first display channel, a second display channel, a third display channel, a fourth display channel, a fifth display channel and a sixth display channel, the first display channel, the second display channel and the third display channel are rotated about Y-axis of a global coordinate system by a predetermined angle, the fourth display channel, the fifth display channel and the sixth display channel are rotated about Y-axis of a global coordinate system by the predetermined angle, the second display channel is tiled with the first display channel and the third display channel using the second mechanical tiling method respectively, the fifth display channel is tiled with the fourth display channel and the sixth display channel using the second mechanical tiling method respectively, the first display channel and the fourth display channel are tiled with the first mechanical tiling method, the second display channel and the fifth display channel are tiled with the first mechanical tiling method, the third display channel and the sixth display channel are tiled with the first mechanical tiling method.

18. The tiled head-mounted display device of claim 2, wherein the head-mounted display device comprises a first display channel, a second display channel, a third display channel, a fourth display channel, a fifth display channel, a sixth display channel, a seventh display channel and an eighth display channel, the first display channel, the second display channel, the third display channel and the fourth display channel are rotated about Y-axis of a global coordinate system by a predetermined angle, the fifth display channel, the sixth display channel, the seventh display channel and the eighth display channel are rotated about Y-axis of a global coordinate system by the predetermined angle, the second display channel is tiled with the first display channel and the third display channel using the second mechanical tiling method respectively, the third display channel is tiled with the second display channel and the fourth display channel using the second mechanical tiling method respectively, the sixth display channel is tiled with the fifth display channel and the seventh display channel using the second mechanical tiling method respectively, the seventh display channel is tiled with the six display channel and the eighth display channel using the second mechanical tiling method respectively, the first display channel and the fifth display channel are tiled with the first mechanical tiling method, the second display channel and the sixth display channel are tiled with the first mechanical tiling method, the third display channel and the seventh display channel are tiled with the first mechanical tiling method, the fourth display channel and the eighth display channel are tiled with the first mechanical tiling method.

19. The tiled head-mounted display device of claim 18, wherein the tiled head-mounted display has a horizontal field of view of at least 120°

and a vertical field of view of at least 50°

.

20. The tiled head-mounted display device of claim 3, wherein the tiled head-mounted display system comprises a first display channel and a second display channel tiled by the first optical tiling method, the first display channel is rotated by a first angle in YOZ plane about X-axis of a global coordinate system, the second display channel is rotated by ±

180°

about Z axis and then rotated by the first angle in the opposite direction about X-axis of the global coordinate system.

21. The tiled head-mounted display device of claim 20, wherein the tiled head-mounted display has a horizontal field of view of at least 50°

and a vertical field of view of at least 40°

.

22. The tiled head-mounted display device of claim 3, wherein the tiled head-mounted display system comprises a first display channel and a second display channel tiled by the second optical tiling method, the first display channel is rotated by a second angle in XOZ plane about Y-axis of a global coordinate system, the second display channel is rotated by the second angle in the opposite direction about Y-axis of the global coordinate system.

23. The tiled head-mounted display device of claim 22, wherein the tiled head-mounted display has a horizontal field of view of at least 70°

and a vertical field of view of at least 30°

.

24. The tiled head-mounted display device of claim 3, wherein the tiled head-mounted display system comprises a first display channel, a second display channel, a third display channel and a fourth display channel, the first display channel and the third display channel are rotated by a second angle in XOZ plane about Y-axis of a global coordinate system, the second display channel and the fourth display channel are rotated by the second angle in the opposite direction about Y-axis of the global coordinate system, the first display channel and the second display channel are tiled with the second optical tiling method, the third display channel and the fourth display channel are tiled with the second optical tiling method, the first display channel and the third display channel are tiled with the first optical tiling method, and the second display channel and the fourth display channel are tiled with the first optical tiling method.

25. The tiled head-mounted display device of claim 24, wherein the tiled head-mounted display has a horizontal field of view of at least 70°

and a vertical field of view of at least 50°

.

26. The tiled head-mounted display device of claim 2, further comprising an auxiliary lens with free-form surfaces, each lens cooperates with the corresponding prism with free-form surfaces, so that the user is able to see external scenery, wherein the second optical surface (3) of the prism with free-form surfaces is a semi-transmissive and semi-reflective surface.

27. The tiled head-mounted display device of claim 26, wherein a material used in the additional prism lens with free-form surfaces has a refractive index N_d1 of 1.4<

N_d1<

1.8 and a Abbe numberV_d1 above 20.

28. The tiled head-mounted display device according to claim 1, wherein the exit pupil diameter is at least 6 mm.

29. The tiled head-mounted display device according to claim 1, wherein the eye clearance is at least 15 mm.

30. The tiled head-mounted display device according to claim 1, wherein the tiling method comprise cementing, adhering, welding and integral injection molding.

17. The tiled head-mounted display device of claiml6, wherein the tiled head-mounted display has a horizontal field of view of at least 100°

and a vertical field of view of at least 50°

.