Augmented Reality Waveguide With Region-Specific Focal Parameters

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Solution Overview

Problem

In augmented reality systems, particularly in static near-eye displays, there is a need to concurrently provide high-quality images of both real and virtual objects across the entire field of view, while ensuring user comfort by dynamically controlling the focus of images, which is challenging with fixed optical properties.

Innovation Solution

An optical system is configured to direct both augmented and real image light along a common optical path for far and close objects, using a projecting optical device with varying focal parameters across different regions of the field of view, allowing the augmented image light to be modified before interaction with a light combining surface to maintain the real image's focus.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a static optical system with fixed optical properties is used, then the system structure is simple and easy to manufacture, but it cannot provide dynamic focus control for both real and augmented images simultaneously

Engineering Contradiction:
Improvefocus control capabilityVSAvoidoptical system structure
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent applies local quality by implementing different optical properties in different regions of the waveguide. Specifically, the upper portion of the waveguide has optical properties optimized for far-distance viewing, while the lower portion has optical properties optimized for near-distance viewing. This allows the static optical system to provide differentiated focus control for different viewing zones without requiring dynamic adjustment mechanisms, thereby resolving the contradiction between ease of operation and device complexity.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If the augmented image light is modified to improve focus, then the augmented image quality is improved, but the real image focus may be affected negatively

Engineering Contradiction:
Improveaugmented image focus qualityVSAvoidreal image focus stability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent applies segmentation by dividing the waveguide into distinct upper and lower portions, each with independently optimized optical properties. The upper portion modifies augmented image light for far-distance focus while the lower portion modifies augmented image light for near-distance focus. This segmentation allows focused modification of augmented image quality in each region without negatively affecting real image focus stability, as each portion is designed to handle specific viewing distances independently.

Inventive Principle:
Principle #1Segmentation

3Device complexity

If a single optical path is used for both real and augmented images, then the system structure is simplified, but it becomes difficult to provide different focal parameters for different viewing zones

Engineering Contradiction:
Improveoptical path configurationVSAvoidfocal parameter variation capability
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent applies local quality by implementing region-specific optical properties within the unified waveguide structure. The upper portion of the waveguide is configured with optical properties for far-distance viewing, while the lower portion is configured with optical properties for near-distance viewing. This allows the single optical path to provide differentiated focal parameters for different viewing zones through spatial variation of optical properties, thereby maintaining structural simplicity while achieving adaptability.

Inventive Principle:
Principle #3Local quality

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 ensures in-focus images for both augmented and real images across the field of view, enhancing user comfort by maintaining the real image's focus while modifying the augmented image's convergence, effectively addressing the challenge of presenting both types of images simultaneously with improved clarity and comfort.

Implementation Method 1

In such waveguides, light carrying an augmented image is guided by total internal reflection to a partially reflective surface from which it is reflected to a viewer.

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

a light directing device configured for directing input light, including light indicative of an augmented image being projected and input light indicative of a real image of an external scene, to propagate in a general propagation direction to an imaging plane

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3574360B1Augmented reality imaging system
Publication Date: 2024.07.10 LUMUS LTD
  • EP3574360B1 patent drawingFigure 1~2B
  • EP3574360B1 patent drawingFigure 3A~3B
  • EP3574360B1 patent drawingFigure 4A~4B

AI summary

An optical system is presented for use in an augmented reality imaging system. The optical system comprises a light directing device, and a projecting optical device. The light directing device is configured for directing input light, including light indicative of an augmented image to be projected and input light indicative of a real image of an external scene, to propagate to an imaging plane. The projecting optical device has a fixed field of view and has a plurality of different focal parameters at different regions thereof corresponding to different vision zones within the field of view. The projecting optical device is configured to affect propagation of at least one of light indicative of the augmented image and light indicative of the real image, such that, for each of the different regions, interaction of a part of the light indicative of the augmented image and a part of the light indicative of the real image with said region of projecting optical device directs the parts of augmented image light and real image along a substantially common output propagation path, corresponding to the focal parameter of said region.