Cholesteric Liquid Crystal Laminate for Efficient Light-Guide Coupling
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing optical elements for augmented reality glasses have low light use efficiency, limiting the field of view (FOV) and preventing the display of wide images.
Innovation Solution
An optical laminate comprising first and second cholesteric liquid crystal layers with different helical pitches and aligned optical axis rotation directions, designed to refract incident light with high efficiency into a light guide plate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a single cholesteric liquid crystal layer is used for light reflection, then the device structure is simple, but the light use efficiency is low and the field of view is limited
Solution Approach 1:
The optical laminate divides the light reflection function into multiple segments by stacking first and second cholesteric liquid crystal layers with different helical pitches. Each layer handles specific wavelength ranges, improving overall light use efficiency and field of view while maintaining manageable structural complexity through modular design
Solution Approach 2:
The invention uses composite material structure by combining cholesteric liquid crystal layers with different helical pitch characteristics. This composite approach enables broader spectral coverage and improved light reflection efficiency across multiple wavelengths, resolving the contradiction between simplicity and performance
2Area of stationary object
If cholesteric liquid crystal layers with different helical pitches are used, then the field of view and light use efficiency are improved, but the manufacturing precision requirements increase
Solution Approach 1:
The invention systematically varies the helical pitch parameter between the first and second cholesteric liquid crystal layers to target specific wavelength ranges. By establishing clear parameter relationships (different pitches for different wavelengths), the manufacturing process can control pitch variations to achieve desired optical performance without excessive complexity
Solution Approach 2:
Different regions of the optical laminate (first and second layers) are assigned different helical pitch qualities to optimize performance for specific wavelength ranges. This local differentiation improves overall field of view while allowing each layer to be manufactured with focused precision requirements for its specific function
3Productivity
If the optical axis rotation directions are aligned in both cholesteric liquid crystal layers, then the light refraction efficiency is improved, but the device complexity increases due to alignment control
Solution Approach 1:
The invention merges the optical axis rotation directions of the first and second cholesteric liquid crystal layers to work cooperatively in the same rotational sense. This combining approach enhances light refraction efficiency by creating consistent optical path control, while the alignment control becomes part of the standard manufacturing process rather than an additional complexity
Solution Approach 2:
By aligning the optical axis rotation directions in both layers, the invention creates homogeneous optical behavior across the laminate structure. This homogeneity improves light refraction efficiency and simplifies the control mechanism, as uniform alignment can be achieved through standardized manufacturing processes rather than complex individual control
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 enhances light use efficiency, enabling wider field of view and improved image display in AR glasses and similar 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. As a result, 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
Implementation Method 2
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 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.