Optical Laminate Suppressing Crosstalk in AR Displays
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In augmented reality glasses, the lamination of cholesteric liquid crystal layers for color display leads to crosstalk issues, causing double images due to differing diffraction angles of light components, particularly between blue and green light reflections.
Innovation Solution
An optical laminate comprising cholesteric liquid crystal layers with specific helical pitch differences and opposite circular polarization reflection directions is used, ensuring that blue and green light are reflected at the same angle, preventing crosstalk and double images.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If cholesteric liquid crystal layers are laminated for color display, then color display capability is improved, but crosstalk and double images occur due to differing diffraction angles
Solution Approach 1:
The patent changes the helical pitch parameter of the cholesteric liquid crystal layers to satisfy a specific mathematical relationship. By setting the helical pitches of adjacent layers to follow the ratio relationship described in the invention, the diffraction angles for different wavelengths are synchronized, eliminating crosstalk while maintaining color display capability through the lamination structure
Solution Approach 2:
The patent divides the color display function into multiple segmented cholesteric liquid crystal layers, each reflecting a specific wavelength range. By segmenting the reflection function across multiple layers with controlled helical pitches, the system achieves full-color display while preventing inter-layer crosstalk through the pitch ratio relationship
2Measurement precision
If cholesteric liquid crystal layers with different helical pitches are used for different wavelengths, then wavelength-selective reflection is improved, but reflection angles differ causing multiple images
Solution Approach 1:
The patent establishes a specific parameter relationship between the helical pitches of different layers. By controlling the pitches to satisfy the mathematical relationship in the invention, the system achieves both wavelength-selective reflection and consistent reflection angles, resolving the contradiction between spectral selectivity and angular consistency
Solution Approach 2:
Instead of using identical helical pitches for all layers (which would give consistent angles but poor wavelength selectivity), or completely different pitches (which would give wavelength selectivity but inconsistent angles), the patent inverts the conventional approach by using pitches that follow a specific ratio relationship, achieving both goals simultaneously
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 suppresses crosstalk and multiple image occurrences in AR glasses by aligning the reflection angles of blue and green light components, enhancing image display clarity.
Implementation Method 1
cholesteric liquid crystal layers that are obtained by immobilizing a cholesteric liquid crystalline phase... turning directions of circularly polarized light to be reflected are opposite to each other
Implementation Method 2
a first cholesteric liquid crystal layer and a second cholesteric liquid crystal layer that are obtained by immobilizing a cholesteric liquid crystalline phase
Implementation Method 3
light (projection light) projected from a display is diffracted (refracted) using a diffraction element to be incident into one end part of a light guide plate
Implementation Method 4
the light is introduced into the light guide plate at an angle such that the light is totally reflected and propagates in the light guide plate
Data Source
AI summary
Provided are an optical laminate where the occurrence of crosstalk can be suppressed and the occurrence of multiple images can be suppressed, a light guide element, and an image display apparatus. The optical laminate includes: a first cholesteric liquid crystal layer and a second cholesteric liquid crystal layer that are obtained by immobilizing a cholesteric liquid crystalline phase and have a liquid crystal alignment pattern in which a direction of an optical axis derived from a liquid crystal compound changes while continuously rotating in at least one in-plane direction, in the first and second cholesteric liquid crystal layers, turning directions of circularly polarized light to be reflected are opposite to each other, helical pitches P1 and P2 of the first and second cholesteric liquid crystal layers satisfy P1<P2, rotation directions of the direction of the optical axis derived from the liquid crystal compound that continuously rotates in one in-plane direction in the liquid crystal alignment pattern are opposite to each other, and lengths Λ1 and Λ2 of the single periods of the first and second cholesteric liquid crystal layers satisfy Λ1<Λ2.