Multi-region Diffractive Waveguide with Continuous Grating Transitions

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Solution Overview

Problem

Existing optical waveguides with multiple gratings suffer from beam fragmentation and power loss due to sharp interfaces between grating regions, which limits their ability to implement complex optical functions and reduces efficiency.

Innovation Solution

A multi-region diffractive optical element with continuous diffractive optical responses in two dimensions, eliminating sharp interfaces and allowing for smooth transitions, thereby reducing beam fragmentation and increasing efficiency by maintaining light direction and power within the waveguide.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If sharp interfaces between grating regions are used in multi-region diffractive optical elements, then distinct optical functions can be implemented in different regions, but beam fragmentation and power loss occur

Engineering Contradiction:
Improveoptical function implementationVSAvoidpower loss
Core Design Contradiction:
Adaptability or versatilityVSLoss of energy

Solution Approach 1:

The patent introduces intermediate transition regions between distinct grating regions, where the grating period continuously changes from the value in one region to the value in the adjacent region. These transition regions act as intermediaries that smoothly connect different optical zones, preventing beam fragmentation and power loss that would otherwise occur at sharp interfaces.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent varies the grating period parameter continuously across transition regions, creating a smooth gradient between different grating zones. This parameter change approach eliminates abrupt discontinuities, allowing light to propagate through multiple bounces without fragmentation while maintaining the distinct optical functions of each region.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If multiple gratings are used to implement complex optical functions, then versatile optical behavior is achieved, but beam fragmentation occurs due to sharp interfaces

Engineering Contradiction:
Improveoptical behavior complexityVSAvoidbeam integrity
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The transition regions serve as intermediary zones that connect distinct grating regions with different optical functions. By providing continuous parameter variation in these intermediate zones, the patent maintains beam integrity while still enabling complex optical behavior through the combination of multiple functional regions.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If traditional multi-region DOEs with fading interfaces are used, then some optical functions are implemented, but total efficiency is reduced

Engineering Contradiction:
Improveoptical function implementationVSAvoidtotal efficiency
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent employs continuous parameter changes in the grating period across transition regions, which maintains higher diffraction efficiency compared to fading interfaces. This approach preserves beam power while enabling multiple optical functions, thereby improving total system efficiency.

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

The solution enables more efficient light propagation with reduced sensitivity to position and angle changes, enhancing the predictability and robustness of the optical waveguide's behavior, while minimizing power loss and fragmentation.

Implementation Method 1

a diffractive optical element provided on a surface or within the waveguide body, the diffractive optical element extending in said two dimensions and each location of the diffractive optical element having a diffractive optical response for light directed thereto

Methodology Applied
Scientific EffectDiffraction: Diffraction

Data Source

PatentEP3710873B1Optical waveguide and diffractive waveguide display
Publication Date: 2023.08.23 DISPELIX OY
  • EP3710873B1 patent drawingFigure 1
  • EP3710873B1 patent drawingFigure 2A~2B

AI summary

The invention relates to an optical waveguide comprising a waveguide body (10) capable of guiding light in a waveguide plane in two dimensions,and a diffractive optical element (22A) provided on a surface or within the waveguide body (10), the diffractive optical element (22A) extending in said two dimensions and each location of the diffractive optical element (22A) having a diffractive optical response for light directed thereto. According to the invention, the diffractive optical element (22A) is a multi-region element comprising a plurality of regions (24A) with different diffractive optical responses. Furthermore, the diffractive optical response of the diffractive optical element between said regions changes continuously in the waveguide plane. The invention also relates to a diffractive waveguide display comprising such waveguide.