Optical Waveguide Recycling Zero-Order Light

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Diffractive waveguide systems suffer from low light transmission efficiency due to energy loss, particularly because zero-order light is not reused, and existing methods struggle to effectively control the quality of optical microstructures during manufacturing.

Innovation Solution

An optical waveguide apparatus incorporating an optical waveguide element and an optical recycling element, where the optical recycling element on the second surface changes the transmission direction of incident light to generate recycled light, which is then reused within the optical waveguide element, enhancing light beam transmission efficiency and maintaining image resolution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If diffractive optical microstructures are used to change light direction, then light progression direction and angle are controlled, but optical energy is lost because zero-order light is not re-used

Engineering Contradiction:
Improvelight transmission efficiencyVSAvoidoptical energy loss
Core Design Contradiction:
Use of energy by moving objectVSLoss of energy

Solution Approach 1:

The patent recovers zero-order light that would otherwise be discarded by diffractive optical elements. A mirror is positioned to reflect zero-order light back through the diffractive optical element, converting it into usable diffracted light orders. This recycling process transforms wasted energy into useful light that contributes to the augmented reality display, directly resolving the energy loss problem.

Inventive Principle:
Principle #34Discarding and recovering

Solution Approach 2:

The patent implements continuous light recycling within the waveguide system. Zero-order light is continuously reflected back and converted into higher-order diffracted light that remains trapped and propagates within the waveguide. This creates a continuous cycle where light that would normally be lost is continuously recovered and reused, maintaining useful optical action throughout the system.

Inventive Principle:
Principle #20Continuity of useful action

2Use of energy by moving object

If optical microstructure design is optimized to improve light efficiency, then light transmission efficiency increases, but manufacturing feasibility and quality control become more difficult

Engineering Contradiction:
Improvelight transmission efficiencyVSAvoidmanufacturing feasibility
Core Design Contradiction:
Use of energy by moving objectVSEase of manufacture

Solution Approach 1:

The patent uses a master mold to create precise diffractive optical element patterns that are then replicated through molding processes. This copying approach allows complex diffraction patterns to be manufactured with high precision and consistency across multiple production runs, maintaining both optical performance and manufacturing feasibility.

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent optimizes key parameters of the diffractive optical elements including grating period, groove depth, and fill factor to achieve high light efficiency. By carefully selecting and tuning these parameters during the design phase, the system achieves superior optical performance while maintaining compatibility with standard manufacturing processes.

Inventive Principle:
Principle #35Parameter changes

3Loss of energy

If more optical elements are added to recycle light, then optical energy loss is reduced, but device complexity increases

Engineering Contradiction:
Improveoptical energy lossVSAvoidsystem complexity
Core Design Contradiction:
Loss of energyVSDevice complexity

Solution Approach 1:

The patent combines the light recycling function with the existing waveguide structure. The mirror is integrated into the waveguide assembly, and the recycled light follows the same optical path as the primary light. This merging approach adds minimal complexity while achieving effective light recycling, as the recycled light is already directed toward the exit surface without requiring separate delivery paths.

Inventive Principle:
Principle #5Merging (Combining)

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 significantly enhances light beam transmission efficiency, reduces optical energy loss, and maintains consistent color temperature, thereby improving the brightness and resolution of images displayed by the optical waveguide apparatus.

Implementation Method 1

A diffractive waveguide involves a method based on the principle of optical diffraction in which a diffraction phenomenon occurs after a light passes through slit-like microstructures

Methodology Applied
Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 2

a diffraction phenomenon occurs after a light passes through slit-like microstructures, such that a direction of the light is changed

Methodology Applied
Scientific EffectDiffraction: Diffraction

Implementation Method 3

The optical recycling element changes a transmission direction of the incident light to generate a recycled light

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3547008B1Optical waveguide apparatus and display
Publication Date: 2024.11.06 CORETRONIC CORPORATION
  • EP3547008B1 patent drawingFigure 1~3
  • EP3547008B1 patent drawingFigure 4~7
  • EP3547008B1 patent drawingFigure 8~10

AI summary

An optical waveguide apparatus including an optical waveguide element and an optical recycling element is provided. The optical waveguide element includes a first surface and a second surface opposite to the first surface. The first surface or the second surface includes an optical structure. An incident light enters the optical waveguide element via the first surface and is transmitted to the second surface. The optical recycling element is disposed on the second surface of the optical waveguide element. The incident light is transmitted to the optical recycling element via the second surface. The optical recycling element changes a transmission direction of the incident light to generate a recycled light. The recycled light enters the optical waveguide element via the second surface and is transmitted to the first surface.