Optical Laminate Structure for Wider AR Glasses Field of View
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Solution Overview
Problem
Existing optical elements in AR glasses, such as those using cholesteric liquid crystal layers, suffer from low light use efficiency, limiting the field of view (FOV) and preventing the display of wide images.
Innovation Solution
An optical laminate comprising two cholesteric liquid crystal layers with different helical pitches and opposite turning directions of circularly polarized light, allowing for high light refraction efficiency into a light guide plate, and a light guide element with these laminates to enhance the FOV.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single cholesteric liquid crystal layer is used for light refraction, then the device structure is simple, but the light refraction efficiency is low and the field of view is limited
Solution Approach 1:
The patent combines two cholesteric liquid crystal layers with different helical pitches into a single optical laminate. The first layer has a helical pitch optimized for one wavelength range while the second layer has a different helical pitch optimized for another wavelength range, creating a composite structure that refracts light more efficiently across broader spectra than a single layer could achieve alone.
Solution Approach 2:
The optical laminate uses composite material structure by stacking two cholesteric liquid crystal layers with different optical properties. Each layer has distinct helical pitch characteristics that complement each other, forming a composite optical system that achieves superior light refraction efficiency and expanded field of view compared to individual layers.
2Device complexity
If a single cholesteric liquid crystal layer is used, then the device complexity is low, but the field of view and image display quality are limited
Solution Approach 1:
The patent merges two cholesteric liquid crystal layers with different helical pitches into a unified optical laminate structure. This combination allows the system to handle multiple wavelength ranges simultaneously, expanding the field of view and improving image display quality without creating excessive structural complexity.
Solution Approach 2:
The patent extends the optical functionality from a single-layer to a multi-layer configuration, adding a dimensional aspect to the optical laminate. By stacking layers with different helical pitches, the system achieves broader spectral coverage and enhanced light refraction capabilities, effectively expanding the field of view through structural dimensionality.
3Productivity
If cholesteric liquid crystal layers with different helical pitches are combined, then light refraction efficiency improves, but the manufacturing complexity increases
Solution Approach 1:
The patent combines two cholesteric liquid crystal layers with different helical pitches into a single optical laminate to achieve high light refraction efficiency across multiple wavelength ranges. While this increases manufacturing complexity compared to a single layer, the modular layer structure allows for standardized production processes that can be scaled.
Solution Approach 2:
The optical laminate employs composite material construction with two cholesteric liquid crystal layers having different helical pitches. This composite structure enables superior optical performance by leveraging the complementary properties of each layer, and the manufacturing process can be optimized by treating each layer as a distinct functional unit that can be produced and integrated systematically.
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 optical laminate and light guide element achieve a wider field of view by efficiently refracting light, enabling improved image display in AR glasses and other devices.
Implementation Method 1
light (projection light) projected from a display is diffracted (refracted) using a diffraction element to be incident into one end portion of a light guide plate
Implementation Method 2
A general cholesteric liquid crystal layer reflects incident light by specular reflection
Implementation Method 3
The optical laminate and light guide element achieve a wider field of view by efficiently refracting light
Data Source
AI summary
Provided are an optical laminate that can refract incident light with a high use efficiency to be incident into a light guide plate or the like, and a light guide element and an image display device including the optical laminate. The optical laminate includes first and second cholesteric liquid crystal layers that 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 which in the first and second cholesteric liquid crystal layers, helical pitches in a cholesteric liquid crystalline phase are different from each other, turning directions of circularly polarized light to be reflected are the same, and rotation directions of the direction of the optical axis that continuously rotates in at least one in-plane direction in the liquid crystal alignment pattern are the same.