Light Guide Plate Residual Layer Thickness for Uniform Emission
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing light guide plates for Extended Reality applications suffer from non-uniform light intensity emission due to the fixed thickness of the residual layer between the diffraction grating and the substrate.
Innovation Solution
The light guide plate design includes an emission portion with a diffraction grating, where the residual layer thickness is varied to ensure a substantially uniform light intensity. This is achieved by determining the residual layer thickness, refractive index, and height of the diffraction grating in a way that increases diffraction efficiency towards the center of the emission portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a fixed thickness residual layer is used between the diffraction grating and substrate, then the manufacturing process is simple, but the light intensity emission is non-uniform
Solution Approach 1:
The patent applies local quality by varying the residual layer thickness at different positions within the emission portion. Specifically, the residual layer thickness is made non-uniform, with different thicknesses in different regions to compensate for light intensity variations and achieve substantially uniform light emission across the entire emission area.
Solution Approach 2:
The patent changes the physical parameter of residual layer thickness from a fixed value to a variable value across different positions. By adjusting the residual layer thickness parameter spatially, the diffraction efficiency is optimized at each position to achieve uniform light intensity emission while maintaining compatibility with nanoimprint manufacturing processes.
2Illumination intensity
If the residual layer thickness is varied to improve light intensity uniformity, then the light emission uniformity improves, but the manufacturing complexity increases
Solution Approach 1:
The patent implements local quality by creating spatial variations in the residual layer thickness within the emission portion. This localized modification of the residual layer structure allows different regions to have optimized thickness values for uniform light emission, while the overall structure remains compatible with standard nanoimprint manufacturing techniques.
Solution Approach 2:
The patent incorporates the variable thickness residual layer design into the mold structure before the nanoimprint process. By pre-forming the mold with the desired residual layer thickness distribution, the complex thickness variation is achieved in a single manufacturing step during molding, avoiding the need for post-processing or multiple manufacturing steps.
3Use of energy by moving object
If the diffraction grating height is increased toward the center of the emission portion, then the diffraction efficiency improves, but the structural complexity increases
Solution Approach 1:
The patent applies local quality by varying the diffraction grating height at different positions within the emission portion. The grating height is made non-uniform, with different heights in different regions to optimize diffraction efficiency locally and achieve substantially uniform light intensity emission across the emission area.
Solution Approach 2:
The patent changes the physical parameter of diffraction grating height from a uniform value to a spatially varying value. By adjusting the grating height parameter across different positions in the emission portion, the diffraction efficiency is optimized at each location to achieve uniform light emission while maintaining manufacturing feasibility through nanoimprint processes.
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 effectively improves the uniformity of light intensity emission, reducing light loss and enhancing the image quality by adjusting the diffraction efficiency and residual layer thickness along the emission portion.
Implementation Method 1
an incidence portion that diffracts incident light into the light guide plate; an emission portion that diffracts the light guided by the substrate and emits the light to a pupil of an observer
Implementation Method 2
a substrate that internally totally reflects the light diffracted into the light guide plate by the incidence portion and guides the light
Data Source
AI summary
To improve the uniformity in the intensity of light to be emitted, by varying the thickness of a residual layer. There is provided a light guide plate including: an incidence portion that diffracts incident light into the light guide plate; a substrate that internally totally reflects the light diffracted into the light guide plate by the incidence portion and guides the light; and an emission portion that diffracts the light guided by the substrate and emits the light to a pupil of an observer, in which: the emission portion includes a diffraction grating; and a residual layer thickness as a thickness of a residual layer formed between the diffraction grating of the emission portion and the substrate is determined such that a light intensity as an intensity of the light emitted from the emission portion is substantially uniform.