Holographic Waveguide Lens With Segmented Grating Light Uniformity Control
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Solution Overview
Problem
Existing grating waveguide AR displays face challenges in achieving uniform light output due to difficulties in precisely controlling diffraction efficiency in distinct regions, leading to insufficient light uniformity in the exit pupil.
Innovation Solution
A holographic waveguide lens design incorporating polymer-dispersed liquid crystal holographic gratings with independently controllable transparent electrodes, divided into sub-regions, and adjustable voltages to manage diffraction efficiency across these regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If gratings with gradually varying diffraction efficiency are designed to improve output uniformity, then light distribution uniformity is improved, but manufacturing complexity and control precision increase significantly
Solution Approach 1:
The out-coupling grating is divided into multiple distinct regions, each with independently controllable diffraction efficiency through separate transparent electrodes. This segmentation allows precise control of light extraction in different areas without requiring complex gradual variation designs, simplifying the overall grating structure while achieving uniform light output.
Solution Approach 2:
Different regions of the out-coupling grating are assigned different diffraction efficiency characteristics tailored to their specific positions and functions. By applying local quality optimization, each region contributes appropriately to the overall light distribution, achieving uniform exit pupil illumination without requiring complex global gradient designs.
2Manufacturing precision
If multiple transparent electrodes with independently controllable voltages are introduced to precisely control diffraction efficiency in different regions, then manufacturing precision and light uniformity are improved, but device complexity increases
Solution Approach 1:
The transparent electrode system is segmented into multiple independently controllable units, each corresponding to a specific grating region. This segmentation enables precise independent control of diffraction efficiency in each area while maintaining a relatively simple overall structure that can be manufactured using standard display technology processes.
Solution Approach 2:
The transparent electrodes serve multiple functions: they control diffraction efficiency, act as alignment references during assembly, and enable independent region control. This multi-functionality reduces the need for additional specialized components, thereby managing device complexity while achieving high manufacturing precision.
3Adaptability or versatility
If polymer-dispersed liquid crystal holographic gratings are used to enable voltage-controlled diffraction efficiency adjustment, then adaptability and light uniformity are improved, but manufacturing complexity increases
Solution Approach 1:
The grating's diffraction efficiency is controlled by changing the voltage parameter applied to the transparent electrodes, which in turn modifies the optical properties of the polymer-dispersed liquid crystal material. This parameter-based control provides high adaptability for adjusting light extraction characteristics without requiring complex structural modifications or multiple different grating types.
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 design enhances the uniformity of exit pupil light by allowing precise control of diffraction efficiency, improving light distribution and reducing manufacturing complexity and costs.
Implementation Method 1
Its principle involves coupling light into a lens through diffraction by a grating, propagating the light within the waveguide lens by total internal reflection, and diffracting the light out of the waveguide lens upon encountering an out-coupling grating
Implementation Method 2
propagating the light within the waveguide lens by total internal reflection
Implementation Method 3
a voltage between the first transparent electrode and the second transparent electrode for each sub-region is set based on an electro-optical response curve and a diffraction efficiency of the polymer-dispersed liquid crystal holographic grating in the sub-region
Data Source
AI summary
The present application provides a holographic waveguide lens and a preparation method thereof, the holographic waveguide lens including a first lens substrate, a second lens substrate, an in-coupling grating, an out-coupling grating, a first transparent electrode, and a second transparent electrode. The first transparent electrode, the out-coupling grating, and the second transparent electrode are collectively divided into a plurality of sub-regions, and a voltage between the first transparent electrode and the second transparent electrode for each sub-region is set based on an electro-optical response curve and a diffraction efficiency of a polymer-dispersed liquid crystal holographic grating in the sub-region. By applying an adjustable voltage to the out-coupling grating located between the first lens substrate and the second lens substrate using the first transparent electrode and the second transparent electrode, the diffraction efficiency of different regions of the out-coupling grating is adjusted, thereby improving the uniformity of exit pupil light.