Head-mounted display with narrow angle backlight

Patent metadata

Field	Value
Publication number	US-11086129-B2
Application number	US-201916273054-A
Country	US
Kind code	B2
Filing date	Feb 11, 2019
Priority date	Feb 21, 2018
Publication date	Aug 10, 2021
Grant date	Aug 10, 2021

Abstract

Methods and systems relating generally to information displays, and more particularly to systems and methods for backlight assemblies for information displays that emit an angularly narrow cone of light. A backlight assembly that emits a narrow angular cone of light can be particularly beneficial in a head-mounted display configuration, such as for use as part of virtual reality or augmented reality systems, where the head-mounted display comprises a lens assembly that directs light from an information display to the eyes of the user. Such a backlight assembly configuration may help reduce undesirable visual effects like flood illumination, ghost images, glare, and scattering.

First claim

The invention claimed is:

1. A head-mounted display comprising:
a display assembly including:
a backlight assembly to illuminate a pixelated display panel;
the pixelated display panel positioned in front of the backlight assembly and configured to generate an image having a corresponding first cone of light; and
a lens assembly configured to direct and focus light of the first cone of light from the pixelated display panel to one or both eyes of a user of the head-mounted display, wherein the lens assembly is capable of directing and focusing light at an angle that is at least 50 degrees greater than a maximum angle of the first cone of light, and wherein the maximum angle of the first cone of light and directions of chief rays associated with the first cone of light correspond to a defined eye box range,

wherein the backlight assembly comprises:
a backlight to emit light of a second cone of light; and
an angle-restricting layer between the pixelated display panel and the backlight, wherein the angle-restricting layer comprises an array of light conductors that each has a width greater than about 10 microns, and each of the light conductors is configured to:
attenuate light of the second cone of light based, at least in part, on angles that the light of the second cone of light strikes the light conductors; and
pass light of the first cone of light to the pixelated display panel.

2. The head-mounted display of claim 1 , wherein each of the light conductors comprises a substantially non-reflective surface that is exposed to the light of the second cone of light.

3. The head-mounted display of claim 1 , wherein each of the individual ones of the light conductors arc is hollow.

4. A head-mounted display comprising:
a display assembly including:
a backlight assembly to illuminate a pixelated display panel;
the pixelated display panel positioned in front of the backlight assembly and configured to generate an image having a corresponding first cone of light; and
a lens assembly configured to direct and focus light of the first cone of light from the pixelated display panel to one or both eyes of a user of the head-mounted display, wherein the lens assembly is capable of directing and focusing light at an angle that is at least 50 degrees greater than a maximum angle of the first cone of light, and wherein the maximum angle of the first cone of light and directions of chief rays associated with the first cone of light correspond to a defined eye box range,

wherein the backlight assembly comprises:
a backlight to emit light of a second cone of light; and
an angle-restricting layer between the pixelated display panel and the backlight, wherein the angle-restricting layer comprises an array of light conductors, and wherein each of the individual ones of the light conductors is tapered, and each of the light conductors is configured to:
attenuate light of the second cone of light based, at least in part, on angles that the light of the second cone of light strikes the light conductors; and
pass light of the first cone of light to the pixelated display panel.

5. The head-mounted display of claim 1 , wherein each of the individual ones of the light conductors is made of a solid light-transmissive material.

6. The head-mounted display of claim 1 , wherein directions of chief rays of light emitted by the backlight assembly substantially match the directions of the chief rays associated with the first cone of light.

7. An optical system comprising:
a backlight assembly to illuminate a pixelated display panel;
the pixelated display panel positioned in front of the backlight assembly and configured to generate an image having a corresponding first cone of light; and
an optical subsystem configured to direct and focus the first cone of light from the pixelated display panel to one or both eyes of a user of the optical system, wherein the optical subsystem is capable of directing and focusing light at an angle that is at least 50 degrees greater than a maximum angle of the first cone of light, and wherein the maximum angle of the first cone of light and directions of chief rays associated with the first cone of light correspond to a defined eye box range,
wherein the backlight assembly comprises:
a backlight to emit light of a second cone of light; and
an angle-restricting layer between the pixelated display panel and the backlight, wherein the angle-restricting layer comprises an array of light conductors that each has a width greater than about 10 microns, and each of the light conductors is configured to:
attenuate light of the second cone of light based, at least in part, on angles that the light of the second cone of light strikes the light conductors; and

pass light of the first cone of light to the pixelated display panel.

8. The optical system of claim 7 , wherein each of the individual ones of the light conductors comprises a substantially non-reflective surface that is exposed to the light of the second cone of light.

9. The optical system of claim 7 , wherein the backlight assembly include a wedge prism array.

10. An optical system comprising:
a pixelated display panel configured to generate an image having a corresponding first cone of light;
an optical subsystem configured to direct and focus the first cone of light from the pixelated display panel to one or both eyes of a user of the optical system; and
a backlight assembly positioned behind the pixelated display panel and configured to illuminate the pixelated display panel by emitting the first cone of light having a maximum angle that is at least 50 degrees less than an angle of light the optical subsystem is capable of directing and focusing to the one or both eyes of the user, wherein the maximum angle of the first cone of light and directions of chief rays associated with the first cone of light correspond to a defined eye box range,
wherein the backlight assembly comprises:
a backlight to emit light of a second cone of light; and
an angle-restricting layer between the pixelated display panel and the backlight, wherein the angle-restricting layer comprises an array of light conductors that each has a width greater than about 10 microns, and each of the light conductors is configured to:
attenuate light of the second cone of light based, at least in part, on angles that the light of the second cone of light strikes the light conductors; and

pass light of the first cone of light to the pixelated display panel.

11. The optical system of claim 10 , wherein each of the individual ones of the light conductors comprises a hole that extend through the angle-restricting layer, and wherein an interior surface of each of the holes is substantially non-reflective.

Assignees

• Valve Corp

Inventors

• Hudman Joshua Mark

Classifications

• G02F1/1336

  Illuminating devices · CPC title

• G02B27/0172 Primary

  characterised by optical features · CPC title

• G02B6/005

  provided by one optical element, or plurality thereof, placed on the light output side of the light guide · CPC title

• G02B6/0036

  2-D arrangement of prisms, protrusions, indentations or roughened surfaces · CPC title

• G02B6/0033 Primary

  Means for improving the coupling-out of light from the light guide · CPC title