Liquid Crystal Diffraction Element for Uniform AR Display Brightness
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In augmented reality (AR) glasses, the brightness of light emitted from a light guide plate is non-uniform due to uniform diffraction efficiency in the plane of the liquid crystal diffraction element, leading to inconsistent light distribution.
Innovation Solution
A liquid crystal diffraction element with an optically-anisotropic layer that has a liquid crystal alignment pattern where the direction of the optical axis continuously rotates in one in-plane direction, and the diffraction efficiency increases from one side to another side, ensuring uniform brightness by varying the thickness and retardation of the optically-anisotropic layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If uniform diffraction efficiency is used across the liquid crystal diffraction element, then the manufacturing process is simple, but the brightness of light emitted from the light guide plate becomes non-uniform
Solution Approach 1:
The patent applies local quality by making the diffraction efficiency position-dependent across the light guide plate. The diffraction efficiency is designed to be lower at positions closer to the light source and higher at positions farther from the light source, creating a non-uniform distribution that compensates for the natural light intensity decay and achieves uniform brightness across the display area.
2Illumination intensity
If diffraction efficiency increases from one side to another side, then uniform brightness is achieved, but the light distribution becomes inconsistent
Solution Approach 1:
The patent employs parameter changes by systematically varying the diffraction efficiency parameter across different positions of the light guide plate. This is achieved by controlling the liquid crystal alignment pattern and optical axis orientation to create a spatially varying diffraction efficiency profile, where the efficiency parameter changes continuously from one side of the plate to the other.
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 achieves uniform brightness of light emitted from the light guide plate, enhancing the viewing experience by maintaining consistent light intensity across the viewing zone through controlled diffraction efficiency.
Implementation Method 1
an optically-anisotropic layer that is formed of a composition including a liquid crystal compound, in which the optically-anisotropic layer has a liquid crystal alignment pattern in which a direction of an optical axis derived from the liquid crystal compound continuously rotates in at least one in-plane direction
Implementation Method 2
an optically-anisotropic layer that is formed of a composition including a liquid crystal compound
Implementation Method 3
a liquid crystal diffraction element that diffracts incident light
Data Source
AI summary
Provided are a liquid crystal diffraction element that can make the brightness of light emitted from a light guide plate uniform and a light guide element. The liquid crystal diffraction element includes: an optically-anisotropic layer that is formed of a composition including a liquid crystal compound, in which the optically-anisotropic layer has a liquid crystal alignment pattern in which a direction of an optical axis derived from the liquid crystal compound continuously rotates in at least one in-plane direction, and a diffraction efficiency of the optically-anisotropic layer increases from one side to another side in the one in-plane direction.