Waveguide 3D Display With Multi-Viewpoint Coupling Gratings

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Solution Overview

Problem

Current parallax 3D technology causes dizziness and discomfort due to a mismatch between the focus position of a single eye and the convergence distance of lines of sight for two eyes, as it only provides binocular parallax images without optical field information for single-eye focusing.

Innovation Solution

A display device with an optical waveguide layer, a first coupling grating to change the direction of light beams, and a second coupling grating to converge light beams at predetermined viewpoints within the visual range of a pupil, ensuring the focal length of a single eye matches the convergence distance of lines of sight for two eyes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If parallax 3D technology is used to provide binocular parallax images, then 3D effect is achieved, but the focus position of single eye mismatches with convergence distance of two eyes lines of sight causing dizziness and discomfort

Engineering Contradiction:
Improve3D display comfortVSAvoidoptical field information for focusing
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The patent segments the optical field information into multiple discrete viewpoints within the pupil's visual range. By dividing the continuous optical field into discrete angular segments (viewpoints), the system can control light paths for different convergence distances while maintaining focus consistency, thereby resolving the mismatch between single-eye focus and binocular convergence.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an angular dimension by creating multiple viewpoints within the pupil's visual range. Instead of treating the optical field as a single plane, the system adds depth in the angular domain, allowing light beams to converge at different distances while maintaining proper focus relationships, thus eliminating the dizziness caused by focus-convergence mismatch.

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

2Adaptability or versatility

If multiple light beams with different image information are transmitted through the optical waveguide layer, then multiple viewpoints are formed, but the light beams may not converge accurately at different viewpoints within the single pupil

Engineering Contradiction:
Improvenumber of viewpointsVSAvoidviewpoint convergence accuracy
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent uses coupling gratings as intermediary optical elements to precisely control and redirect light beams toward specific viewpoints within the pupil. These gratings act as mediators that transform light paths, ensuring accurate convergence at multiple discrete viewpoints while maintaining image quality and reducing crosstalk between adjacent viewpoints.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If the first coupling grating changes the direction of light beams toward the light-exiting region, then light transmission is achieved, but the direction control precision affects the accuracy of viewpoint formation

Engineering Contradiction:
Improvelight transmission efficiencyVSAvoiddirection control precision
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent employs coupling gratings with specifically designed parameters (grating period, orientation, depth) to control light beam directions. By optimizing these parameters, the system achieves high transmission efficiency while maintaining precise direction control, ensuring that light beams accurately converge at the intended viewpoints within the pupil's visual 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

Prevents dizziness by aligning the focal length of a single eye with the convergence distance of two eyes, allowing for a 3D effect without discomfort, while maintaining image quality and immersion.

Implementation Method 1

a first coupling grating arranged on a transmission path of the at least two types of light beams in the optical waveguide layer, and configured to change a direction of each of the at least two types of light beams having entered the optical waveguide layer, to enable each of the at least two types of light beams in the optical waveguide layer to transmit in a direction toward the light-exiting region

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

a second coupling grating arranged in the optical waveguide layer at a position corresponding to the light-exiting region, and configured to enable light beams formed by light beams having same image information in the at least two types of light beams to exit from the light-exiting region and be converged at a same viewpoint, and enable light beams formed by light beams having different image information in the at least two types of light beams to exit from the light-exiting region and be converged at different viewpoints

Methodology Applied
Scientific EffectDiffraction: Diffraction

Data Source

PatentEP3770669B1Display apparatus and display method
Publication Date: 2024.06.26 BOE TECHNOLOGY GROUP CO LTD
  • EP3770669B1 patent drawingFigure 1~3
  • EP3770669B1 patent drawingFigure 4~7
  • EP3770669B1 patent drawingFigure 8~10

AI summary

A display device includes: an optical waveguide layer (1) having a light-entering region and a light-exiting region; an optical element (4) correspondingly arranged in the light-entering region and configured to emit at least two types of light beams having different image information, to transmit the at least two types of light beams to the light-entering region of the optical waveguide layer; at least two coupling gratings (2) arranged on transmission paths of the at least two types of light beams in the optical waveguide layer, and configured to change a direction of each of the at least two types of light beams in the optical waveguide layer, to enable light beams in the at least two types of light beams in the optical waveguide layer to be transmitted to the light-exiting region, enable light beams formed by light beams having same image information in the two types of light beams in the optical waveguide layer to exit from the light-exiting region and be converged at a same view point, and enable light beams formed by light beams having different image information in the at least two types of light beams to exit from the light-exiting region and be converged at different viewpoints.