Waveguide Display Device Removing Relay Optics for Compact AR

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Solution Overview

Problem

Current near-to-eye display technologies based on diffractive optics have a small range of an exit pupil, large volume, and significant weight, which hinders miniaturization and user experience in augmented reality applications.

Innovation Solution

A waveguide display device comprising a waveguide substrate and optical elements that couple incident light in a way to eliminate the need for a relay optical element, allowing light to propagate in multiple directions and reduce device volume and weight, while maintaining a large exit pupil range.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If conventional diffractive optics near-to-eye display technology is used, then virtual and real scenes can be superimposed, but the device has large volume and significant weight

Engineering Contradiction:
Improvesuperimposition of virtual and real scenesVSAvoiddevice weight
Core Design Contradiction:
Ease of operationVSWeight of stationary object

Solution Approach 1:

The patent removes the relay optical element from the conventional display system, extracting a component that contributes to volume and weight while maintaining the core function of light coupling and direction control through the remaining optical elements

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent combines the functions of multiple optical elements into a more integrated structure where the waveguide substrate and remaining optical elements work together to achieve both light coupling and direction control, reducing the overall component count and device volume

Inventive Principle:
Principle #5Merging (Combining)

2Ease of operation

If conventional diffractive optics near-to-eye display technology is used, then virtual and real scenes can be superimposed, but the device has large volume

Engineering Contradiction:
Improvesuperimposition of virtual and real scenesVSAvoiddevice volume
Core Design Contradiction:
Ease of operationVSVolume of stationary object

Solution Approach 1:

The patent removes the relay optical element from the conventional display system, extracting a component that contributes to volume while maintaining the core function of light coupling and direction control through the remaining optical elements

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent utilizes the thickness dimension of the waveguide substrate to achieve light coupling and direction control, transitioning from a planar arrangement to a three-dimensional optical path that reduces lateral volume requirements

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Ease of operation

If conventional diffractive optics near-to-eye display technology is used, then virtual and real scenes can be superimposed, but the exit pupil range is small

Engineering Contradiction:
Improvesuperimposition of virtual and real scenesVSAvoidexit pupil range
Core Design Contradiction:
Ease of operationVSArea of stationary object

Solution Approach 1:

The patent utilizes the thickness dimension of the waveguide substrate to achieve light coupling and direction control, transitioning from a planar arrangement to a three-dimensional optical path that reduces lateral volume requirements

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent changes the optical parameters by using multiple optical elements with different functions (first optical element for coupling, second optical element for direction control, third optical element for eye coordination) to achieve both compact size and large exit pupil range

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration enables a compact, lightweight waveguide display with a large exit pupil range, enhancing user experience by allowing seamless superimposition of virtual and real scenes, and supporting miniaturization in augmented reality devices.

Implementation Method 1

The waveguide substrate is configured to couple the light coupled-in by the first optical element to the second optical element

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

The second optical element is configured to couple the light coupled to it by the waveguide substrate to the third optical element in a first direction and a second direction

Methodology Applied
Scientific EffectDiffraction: Diffraction

Implementation Method 3

The waveguide substrate is configured to couple the light coupled-in by the first optical element to the second optical element

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Data Source

PatentEP4174558B1Waveguide display device and augmented reality display apparatus
Publication Date: 2024.11.06 BEIJING XIAOMI MOBILE SOFTWARE CO LTD
  • EP4174558B1 patent drawingFigure 1~2
  • EP4174558B1 patent drawingFigure 3~4
  • EP4174558B1 patent drawingFigure 5

AI summary

A waveguide display device (1) and an augmented reality display apparatus are provided. The waveguide display device (1) includes a waveguide substrate (11) and a first optical element (12), a second optical element (13) and a third optical element (14) coupled to the waveguide substrate (11). The first optical element (12) is configured to couple an incident light into the waveguide substrate (11). The second optical element (13) is configured to couple the light coupled-in by the waveguide substrate (11) to the third optical element (14) in a first direction and a second direction. The third optical element (14) is configured to couple the light coupled to it by the second optical element (13) to the second optical element (13) in the first direction or the second direction, and to couple to the light coupled to it by the second optical element (13) out to the human eye.