Near-eye display apparatus

• US 10,330,937 B2
• Filed: 01/03/2018
• Issued: 06/25/2019
• Est. Priority Date: 12/06/2011
• Status: Active Grant

• Current Assignee: Beijing NED+AR Display Technology Co., Ltd.
• Original Assignee: Beijing NED+AR Display Technology Co., Ltd.
• Inventors: Cheng, Dewen, Wang, Qiwei
• Primary Examiner(s): Hasan, Mohammed A
• Application Number:
  US15/860,787
• Publication Number:
  US 20180143440A1
• Time in Patent Office: 538 Days
• Field of Search: 359630-633, 359649-655, 359245, 359248, 359900
• CPC Class Codes: G02B 2027/0114 comprising dichroic elements
• CPC Class Codes: G02B 2027/0125 Field-of-view increase by wavefront division
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 5/04 Prisms
• CPC Class Codes: G02B 5/045 Prism arrays
• CPC Class Codes: G02B 6/0031 Reflecting element, sheet or layer
• CPC Class Codes: G06T 19/006 Mixed reality object pose determination, tracking or camera calibration for mixed reality G06T7/00
• CPC Class Codes: H04N 13/144 for flicker reduction
• CPC Class Codes: H04N 13/344 with head-mounted left-right displays
• CPC Class Codes: H04N 13/346 using prisms or semi-transparent mirrors
• CPC Class Codes: H04N 13/363 using image projection screens volumetric display H04N13/388
• CPC Class Codes: H04N 2213/001 Constructional or mechanical details

Abstract

A wearable augmented reality (AR) or virtual reality (VR) display apparatus includes an optical waveguide; an optical free-form surface; and a microdisplay; wherein optical free-form surface is optically coupled to the waveguide through an inclined optical path. A near-eye display apparatus includes two or more layers of waveguide plates arranged to overlap with each other, wherein within each layer of the waveguide plate includes multiple reflective surfaces different in reflectivity, so as to ensure that light transmitted through the waveguide plate has a substantially uniform distribution of intensity in a predetermined area when exiting outward from the waveguide plate. The waveguide optical element is ultrathin so as to be directly mounted into a spectacle frame. User experience and contrast level are also improved.

Claims

1. A near-eye display apparatus, comprising:

a waveguide optical element comprising at least two waveguide plates having a light-transmission gap therebetween; and

a projection optical assembly including a free-form curved surface optical element;

wherein the projection optical assembly is configured to project light emitted from an image source element onto the waveguide optical element so as to transmit the light in the waveguide optical element.

2. The near-eye display apparatus of claim 1, wherein a coupling exit imaging light area is distributed in different areas along a direction of two main surfaces of each waveguide plate.

3. The near-eye display apparatus of claim 2, wherein the free-form curved surface optical element is a prism having at least three XY polynomial free-form surfaces.

4. The near-eye display apparatus of claim 1, wherein:

the at least two waveguide plates are arranged to overlap with each other in parallel with the air gap predetermined therebetween, each waveguide plate having two main surfaces parallel to each other, configured to transmit light coupled into said waveguide plates, in a predetermined direction through total internal reflection;

each of the at least two waveguide plates comprises at least one partially reflective surface located inside the each waveguide plate, said partially reflective surface is arranged within a space between said main surfaces as a beam-split surface at a predetermined angle with said main surfaces;

the partially reflective surfaces inside the waveguide plates are distributed in different areas along the direction of said main surfaces.

5. The near-eye display apparatus of claim 4, wherein there are multiple partially reflective surfaces inside each waveguide plate, and numbers of the partially reflective surfaces inside the waveguide plates are identical or different.

6. The near-eye display apparatus of claim 4, wherein the predetermined angle is different for different waveguide plates.

7. The near-eye display apparatus of claim 5, wherein the multiple partially reflective surfaces are distributed uniformly in a predetermined distribution area.

8. The near-eye display apparatus of claim 1, wherein the waveguide optical element further comprises coupling incidence portions integrated with or combined with each waveguide plate into a whole, the coupling incidence portions are used for refracting light beams into each waveguide plate so as to make light entering said each waveguide plate satisfy an incidence condition of total internal reflection.

9. The near-eye display apparatus of claim 8, wherein the coupling incidence portions are located on the same side of each waveguide plate, and protrude from waveguide plates in the same direction.

10. The near-eye display apparatus of claim 5, wherein the multiple partially reflective surfaces are configured to have different reflectivity to ensure that light exiting the waveguide plates has a substantially uniform intensity distribution in a predetermined area, the reflectivity of adjacent partially reflective surfaces satisfies the following formula:

11. The near-eye display apparatus of claim 10, wherein the waveguide optical element further comprises coupling incidence portions integrated with or combined with each waveguide plate into a whole, the coupling incidence portions are used for refracting light beams into each waveguide plate so as to make light entering said each waveguide plate satisfy an incidence condition of total internal reflection, at least one of the coupling incidence portions comprises a wedge deflection element.

12. The near-eye display apparatus of claim 1, further comprising an image source element configured to emit the image light to the projection optical assembly.

13. A display apparatus, comprising:

a waveguide optical element;

a projection optical system having a free-form surface optical element; and

a microdisplay;

wherein the projection optical system is optically coupled to the waveguide optical element through an inclined optical path; and

wherein a coupling exit imaging light area is distributed in different areas along a direction of two main surfaces of the waveguide optical element.

14. The display apparatus of claim 13, wherein the waveguide optical element comprises at least two waveguide plates with a light-transmission gap therebetween.

15. The display apparatus of claim 13, wherein the projection optical system comprises a prism having the optical free-form surface;

wherein the prism comprises at least three free-form curved surfaces, has non-overlapping exit pupil positions in two orthogonal directions, a thickness mm, and a width 0 mm.

16. The display apparatus of claim 14, wherein:

the waveguide plates are arranged to overlap with each other in parallel with a predetermined air gap therebetween, each waveguide plate comprising two main surfaces parallel to each other, to transmit light coupled into the waveguide plates, in a predetermined direction by means of total internal reflection;

each of the waveguide plates comprises at least one partially reflective surface located inside each waveguide plate, said partially reflective surface is arranged within a space between said main surfaces as a beam-split surface at a predetermined angle with said main surfaces; and

the partially reflective surface inside the waveguide plates are distributed in different areas along the direction of said main surfaces.

17. The display apparatus of claim 16, wherein there are multiple partially reflective surfaces inside each waveguide plate, and the numbers of the partially reflective surfaces inside the waveguide plates are identical or different.

18. The display apparatus of claim 14, wherein the waveguide optical element further comprises coupling incidence portions integrated with or combined with each waveguide plate into a whole, the coupling incidence portions are used for refracting light beams into the waveguide plates so as to make light entering said each waveguide plate satisfy an incidence condition of total internal reflection, the multiple partially reflective surfaces are configured to have different reflectivity to ensure that light exiting the waveguide plates has a substantially uniform intensity distribution in a predetermined area.

19. The display apparatus of claim 18, wherein the reflectivity of adjacent partially reflective surfaces satisfies the following formula:

20. A method of displaying augmented reality (AR) or virtual reality (VR) images with a wearable display apparatus, the method comprising:

receiving images;

projecting the images with a projection optical system including at least one free-form surface optical element;

coupling the projected images to a waveguide optical element through an inclined optical path, wherein the waveguide optical element comprises at least two waveguide plates with a light-transmission gap therebetween; and

distributing a coupling exit imaging light area in different areas along a direction of two main surfaces of each waveguide plate.