Six-Point Grating Profile for Uniform Diffraction Waveguides

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Solution Overview

Problem

Existing diffraction optical waveguides face challenges with low diffraction efficiency, non-uniformity, and difficulty in designing and processing waveguide gratings, particularly the coupling-in grating, which limits image display brightness.

Innovation Solution

A novel grating structure with a cross-sectional profile defined by six feature points, allowing adjustment of parameters to enhance diffraction efficiency and uniformity, and a stepped grating structure that simplifies processing while maintaining optical effectiveness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If existing waveguide grating designs are used, then the device complexity is reduced, but the diffraction efficiency and uniformity deteriorate

Engineering Contradiction:
Improvediffraction efficiencyVSAvoidgrating structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by precisely controlling the cross-sectional profile parameters of the grating line, including six specific feature points with defined coordinates and heights. By optimizing these geometric parameters, the patent achieves significant improvement in diffraction efficiency and uniformity while maintaining a manageable device complexity through systematic parameter control.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If existing waveguide grating designs are used, then the design simplicity is maintained, but the manufacturing precision deteriorates

Engineering Contradiction:
Improvegrating structure precisionVSAvoidgrating design complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent defines six specific feature points in the cross-sectional profile with precise coordinate parameters, enabling high manufacturing precision through controlled parameter specification. This systematic parameter definition approach allows for accurate fabrication while keeping the design methodology organized and manageable.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent segments the grating line cross-sectional profile into six distinct feature points (P1-P6) with specific geometric characteristics. This segmentation approach facilitates precise manufacturing by breaking down the complex profile into controllable discrete elements, thereby improving manufacturing precision without overwhelming design complexity.

Inventive Principle:
Principle #1Segmentation

3Reliability

If existing waveguide grating designs are used, then the processing simplicity is maintained, but the diffraction uniformity deteriorates

Engineering Contradiction:
Improvediffraction uniformityVSAvoidgrating processing ease
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent achieves improved diffraction uniformity through precise control of six feature point parameters in the cross-sectional profile. The systematic parameter control methodology maintains processing feasibility by providing clear fabrication guidelines, thus balancing uniformity improvement with manufacturing ease.

Inventive Principle:
Principle #35Parameter changes

4Reliability

If the grating structure with six feature points is implemented, then the diffraction efficiency is improved, but the processing difficulty increases

Engineering Contradiction:
Improvediffraction efficiencyVSAvoidprocessing difficulty
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent implements six feature points with specific geometric parameters to achieve high diffraction efficiency. The structured parameter definition provides a clear fabrication roadmap, which mitigates processing difficulty by transforming a potentially complex shape into a series of controllable parameter specifications.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

By segmenting the grating profile into six discrete feature points, the patent makes the processing task more manageable. Each feature point can be controlled independently during fabrication, reducing the overall processing difficulty compared to controlling a continuous complex curve, while still achieving high diffraction efficiency.

Inventive Principle:
Principle #1Segmentation

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

The novel grating structure significantly improves diffraction efficiency and uniformity, reducing processing difficulties and enhancing conformity with the designed structure, leading to improved image display brightness.

Implementation Method 1

The coupling-in grating couples incident light carrying image information into the waveguide substrate... The eye receives the light of the coupled-out light field, and thus, for example, an image carried by the incident light can be observed

Methodology Applied
Scientific EffectDiffraction: Diffraction

Data Source

PatentEP4379257B1Grating structure, diffraction optical waveguide, and display device
Publication Date: 2025.12.10 JIAXING UPHOTON OPTOELECTRONICS TECH CO LTD
  • EP4379257B1 patent drawingFigure 1~2
  • EP4379257B1 patent drawingFigure 3~4
  • EP4379257B1 patent drawingFigure 5~6

AI summary

A grating structure, a diffraction optical waveguide, and a display device are disclosed. The grating line of the grating structure has a cross-sectional profile with a narrow top and a wide bottom, wherein the cross-sectional profile comprises six feature points, and the six feature points respectively have coordinates (0, 0), (L2, H2), (L3, H3 ), (L4, H4), (L5, H5) and (L6, 0) in a cross section, and satisfy following relationships: Hdrop=min(H4,H5)-max(H3,H2)>50nm; 0.1<(L5-L4)/(L3-L2); L3>0.34T; and 0.05T<L5-L4<0.32T. By controlling the parameters of these feature points, the cross-sectional profile can be adjusted, and thus significantly improving the optical effect (comprising diffraction efficiency and uniformity) that the grating structure can achieve, and at the same time increasing degrees of freedom in grating design and optical effect regulation.