Head-Mounted Light Field Display with Integral Imaging and Waveguide Prism

Patent metadata

Field	Value
Publication number	US-2020393677-A1
Application number	US-201816491839-A
Country	US
Kind code	A1
Filing date	Mar 6, 2018
Priority date	Mar 9, 2017
Publication date	Dec 17, 2020
Grant date	—

Abstract

Freeform waveguide prism and use with head-mounted light field display with integral imaging and relay group.

First claim

What is claimed is:

1 . A freeform waveguide prism for imaging a lightfield disposed at a selected point, comprising:
a first freeform optical surface disposed to receive light from the lightfield and refract the received light into the body of the prism; a second freeform optical surface disposed to receive the refracted light from the first freeform optical surface and reflect the light into the body of the prism to provide an intermediate image of the lightfield at a selected location within the body of the prism; a third freeform optical surface disposed to receive the light from the intermediate image and total internally reflect the light into the body of the prism; and a fourth freeform optical surface disposed to receive the reflected light from the third freeform optical surface and reflect the light back to the third freeform surface at an angle that allows the light to exit the prism, the first through fourth freeform optical surfaces cooperating so that the light exiting the prism through the third freeform surface produces an image of the light field at a selected location external to the prism.

2 . The freeform waveguide prism according to claim 1 , wherein the second freeform optical surface is configured to total internally reflect the light into the body of the prism.

3 . The freeform waveguide prism according to claim 1 , wherein the second freeform optical surface is mirrored to reflect the light into the body of the prism.

4 . The freeform waveguide prism according to claim 1 , wherein the third freeform optical surface is configured to total internally reflect the light from the second freeform optical surface into the body of the prism.

5 . The freeform waveguide prism according to claim 1 , wherein the fourth freeform optical surface is mirrored.

6 . The freeform waveguide prism according to claim 1 , wherein the fourth freeform optical surface includes a beamsplitting coating.

7 . The freeform waveguide prism according to claim 1 , wherein for an orthogonal X-Y-Z coordinate system, the Z-axis is along the viewing direction, the Y-axis is parallel to the horizontal direction aligned with interpupilary direction of a user, and the X-axis is in the vertical direction aligning with the head orientation of the user.

8 . The freeform waveguide prism according to claim 7 , wherein the freeform waveguide prism is symmetric about the horizontal (Y-Z) plane.

9 . The freeform waveguide prism according to claim 7 , wherein the first through fourth freeform optical surfaces are decentered along the horizontal Y-axis and rotated about the vertical X-axis.

10 . The freeform waveguide prism according to claim 1 , wherein the shape of any one of the first through fourth freeform optical surfaces is given by

z
=

c


r
2

1
+

1
-

(

1
+
k

)



c
2



r
2

+

∑

j
=
2

6

6



C
j



x
m



y
n




j

=

(

m
+
n

)

2

+
m
+

3

n

2

+
1

,

where z is the sag of the free-form surface measured along the z-axis of a local x, y, z coordinate system, c is the vertex curvature (CUY), r is the radial distance, k is the conic constant, and C j is the coefficient for x m y n .

11 . A head-mounted display integral imaging (InI) system, comprising:
a microscopic InI unit (micro-InI) configured to create light fields of a selected 3D scene at a selected position along an optical axis of the system; a relay unit having a vari-focal element (VFE) disposed therein, the relay unit disposed on the optical axis at a location so the selected position is an optical conjugate of the relay unit, the relay unit configured to receive the light fields created by the microscopic InI unit; and the freeform waveguide prism according to any of the preceding claims for receiving light from the relay unit to provide an image of the 3D scene at an exit pupil of the system for viewing by a user of the head-mounted display system, wherein the VFE is configured to tune the location of the intermediate image within the body of the prism.

12 . The head-mounted display integral imaging (InI) system of claim 11 , wherein the microscopic InI unit (micro-InI) is configured to reproduce full-parallax light fields of a 3D scene having a constrained viewing zone.

13 . The freeform waveguide prism or head-mounted display integral imaging (InI) system of claim 11 , comprising a see-through unit in optical communication with the freeform waveguide prism to transmit a view of a real world

Assignees

• Univ Arizona

Inventors

• Hua Hong
• Huang Hekun

Classifications

• G02B3/0006

  Arrays (G02B3/02, G02B5/188 take precedence) · CPC title

• G02B3/14

  of variable focal length · CPC title

• G02B2027/0178

  Eyeglass type (eyeglass details G02C) · CPC title

• G02F1/313

  in an optical waveguide structure · CPC title

• G02B27/0172 Primary

  characterised by optical features · CPC title