Polarization Rotator for AR Display Distance Matching

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Solution Overview

Problem

Current virtual and augmented reality display devices face issues with distance matching, causing eye-brain conflict and eye strain due to mismatched image distances between the displayed virtual image and the real environment, which existing technologies fail to effectively address.

Innovation Solution

A controllable optical image-generating apparatus coupled with an optical image-viewing apparatus that utilizes a programmable image-generating component, polarization rotator, and polarization-dependent optical elements to adjust the polarization state and image distance, enabling selective control of focal lengths and image distances through a total internal reflection light guide and holographic couplers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a stereoscopic 3D display sends different images to different eyes, then stereoscopic 3D effect is achieved, but the perceived image distance differs from the eye's focal length causing eye-brain conflict and eye strain

Engineering Contradiction:

Improvestereoscopic 3D effectVSAvoideye-brain conflict and eye strain

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent implements a controllable image-generating apparatus that can dynamically adjust the distance of the generated image plane. This dynamic adjustment capability allows the system to match the image distance with the surrounding real image field, resolving the fixed distance mismatch that causes eye-brain conflict in traditional stereoscopic displays.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes the focal length parameter of the display system by using a controllable image-generating apparatus with adjustable focal length. This parameter change enables the perceived image distance to match the eye's focal length, eliminating eye strain while maintaining stereoscopic 3D effect.

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If a displayed image remains in a certain plane, then device structure is simplified, but the viewer cannot focus on the generated image and surrounding objects simultaneously causing distance mismatch

Engineering Contradiction:

Improvedevice structureVSAvoiddistance mismatch between displayed and surrounding images

Core Design Contradiction:

Device complexityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces a controllable image-generating apparatus that can dynamically vary the distance of the generated image plane. This dynamic capability allows the display to adapt its image distance to match the surrounding real image field, enabling the viewer to focus on both the generated image and surrounding objects simultaneously without the distance mismatch problem.

Inventive Principle:

Principle #15Dynamics

3Adaptability or versatility

If the distance of the generated image plane is made adjustable, then distance matching capability is achieved, but device complexity increases

Engineering Contradiction:

Improvedistance matching capabilityVSAvoiddevice structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent replaces traditional mechanical adjustment mechanisms with a controllable image-generating apparatus that uses optical control methods. This substitution achieves distance matching capability through optical means rather than mechanical movement, reducing device complexity while maintaining adaptability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 solution allows for accurate distance matching between the virtual and real image fields, reducing eye strain and enhancing the viewer's ability to focus on both simultaneously, thereby improving the usability of wearable display devices in virtual and augmented reality systems.

Implementation Method 1

a polarization rotator disposed to accept the polarized image output

Methodology Applied

Scientific EffectPolarization rotation: Polarisation

Implementation Method 2

a total internal reflection (TIR) light guide disposed transverse to the optical axis of the optical image-generating apparatus

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 3

a single input holographic coupler disposed at an input region of the TIR light guide; and a single output holographic coupler disposed at an output region of the TIR light guide

Methodology Applied

Scientific EffectHolographic diffraction: Diffraction

Implementation Method 4

a polarization dependent optical element disposed to accept an output from the polarization rotator

Methodology Applied

Scientific EffectPolarization-dependent optical effect: Polarisation

Data Source

PatentUS11442306B2Optical display system, method, and applications

Publication Date: 2022.09.13 UNIVERSITY OF CENTRAL FLORIDA RESEARCH FOUNDATION INC

AI summary

An optical display system includes an information display (image-generating) component, a polarization rotator, a polarization dependent optical element, an input holographic coupler, a light guide and an output holographic coupler. By controlling the polarization of the displayed light through the polarization rotator, the polarization dependent optical element changes the viewable content to different distances from the viewer. This enables the generation of a proper light field which will then be coupled into the light guide through the input holographic coupler, and finally go through the output holographic coupler to a user's eye.