Diffraction Waveguide Layout for Uniform Large-Area AR Brightness
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Solution Overview
Problem
Existing virtual reality technologies struggle to achieve uniform and high brightness light or display over wider areas, particularly in applications like AR HUD, where conventional waveguides fail to maintain consistent brightness across larger surfaces.
Innovation Solution
A waveguide design incorporating input, extended, and output diffraction grating patterns with specific duty cycle variations and standard deviations, ensuring uniformity and brightness by adjusting the duty cycle and pitch of diffraction grating areas to enhance light transmission and out-coupling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If conventional waveguides are used for AR HUD applications, then the device can transmit light over a wider area, but the brightness uniformity deteriorates
Solution Approach 1:
The patent applies local quality by varying the duty cycle of diffraction grating areas along the light propagation path. Different sections of the waveguide have different duty cycles (e.g., input grating area with duty cycle D1, extended grating areas with duty cycles D2-D7, output grating areas with duty cycles D8-D13), which locally adjusts the light coupling and out-coupling characteristics to maintain uniform brightness across the entire wider transmission area.
Solution Approach 2:
The patent changes the duty cycle parameter of the diffraction grating structures along the light path. Specifically, the duty cycle varies from D1 at the input, through D2-D7 in the extended region, to D8-D13 at the output, with each section optimized to compensate for brightness variations and maintain uniform illumination intensity across the extended area.
2Illumination intensity
If the duty cycle of diffraction grating areas is varied to improve brightness uniformity, then the brightness uniformity improves, but the device complexity increases
Solution Approach 1:
The patent segments the diffraction grating structure into multiple distinct areas along the light path: input diffraction grating area, multiple extended diffraction grating areas, and multiple output diffraction grating areas. Each segment has a specific duty cycle optimized for its position, allowing independent optimization of light coupling and out-coupling while maintaining overall brightness uniformity.
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 waveguide achieves uniform brightness and improved light efficiency across larger areas, enhancing virtual and augmented reality displays by maintaining consistent brightness and reducing variations in light transmission.
Implementation Method 1
an input diffraction grating pattern, an extended diffraction grating pattern, and an output diffraction grating pattern where each grating pattern is formed for external light to be in-coupled through the input diffraction grating pattern, sequentially to pass through the extended diffraction grating pattern and the output diffraction grating pattern, and then to be out-coupled by the output diffraction grating pattern
Implementation Method 2
A waveguide is a channel that causes repeated reflections of waves between two boundaries
Data Source
AI summary
Provided is a waveguide and its applications. The waveguide implements, for example, a VR (Virtual Reality) device, an AR (Augmented Reality) device, a MR (Mixed Reality) device, or a XR (extended Reality) device. Provided is a waveguide that can implement a clear display image with more uniform brightness even when implementing a display image under a relatively large area. The waveguide can implement the display image with more uniform brightness while minimizing loss of brightness. Also provided are applications of the waveguide.