Multi-Layered Optical Waveguide for Uniform AR Display Brightness
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Solution Overview
Problem
Current augmented reality head-mounted displays with beam splitter array waveguide architecture suffer from non-uniform brightness due to the display beam not effectively filling the sectional area of the optical waveguide element, leading to uneven image distribution.
Innovation Solution
An optical waveguide element with a multi-layered light guide structure, comprising a first, second, and third light guide layer, where the light entrance and exit surfaces form inclined surfaces, allowing continuous beam splitting and enlargement of the sectional area, ensuring uniform beam distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-layer light guide structure is used, then the device complexity is reduced, but the beam distribution uniformity deteriorates
Solution Approach 1:
The light guide structure is divided into multiple layers (first light guide layer, second light guide layer, and third light guide layer) to achieve continuous beam splitting. Each layer contributes to progressively enlarging the sectional area of the display beam, transforming a single complex structure into multiple simpler layers that work together to improve beam distribution uniformity.
Solution Approach 2:
The patent transitions from a single-layer two-dimensional structure to a multi-layer three-dimensional structure. By stacking multiple light guide layers with different thicknesses and configurations, the system enlarges the beam's sectional area in the vertical dimension, achieving uniform beam distribution that cannot be accomplished with a single layer.
2Volume of moving object
If the light guide layer thickness is reduced, then the device volume is reduced, but the beam filling capability deteriorates
Solution Approach 1:
Instead of using a single thick light guide layer, the structure is segmented into multiple thinner layers (first, second, and third light guide layers with different thicknesses). This segmentation allows the overall device volume to be reduced while the cumulative effect of multiple layers maintains or enhances the beam filling capability through progressive beam splitting and sectional area enlargement.
Solution Approach 2:
The patent employs a nested configuration where multiple light guide layers are stacked one on top of another, with each layer contributing to the beam splitting process. The first, second, and third light guide layers are arranged in a nested manner, allowing the beam to be progressively divided and distributed, achieving effective beam filling within a compact thickness.
3Adaptability or versatility
If the beam splitter array is used, then the viewing angle is widened, but the brightness uniformity deteriorates
Solution Approach 1:
The beam splitter function is distributed across multiple light guide layers, with each layer containing beam splitting structures. This segmentation of the beam splitting function across layers allows the system to maintain wide viewing angle characteristics while achieving uniform brightness distribution through the progressive and continuous beam splitting process.
Solution Approach 2:
The patent implements continuous beam splitting across multiple light guide layers, where the beam is progressively divided at each layer interface. This continuous action of beam splitting and redistribution ensures that the brightness is uniformly distributed across the entire beam path, maintaining uniformity even while providing wide viewing angles through the beam splitter array architecture.
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 multi-layered design enhances beam distribution uniformity, improving brightness and display quality by effectively filling the sectional area of beam splitters, resulting in a more uniform and high-quality display output.
Implementation Method 1
Light entrance surfaces of the first light guide layer and the second light guide layer jointly compose a first inclined surface, and light exit surfaces of the first light guide layer and the second light guide layer jointly compose a second inclined surface. The first inclined surface and the second inclined surface are respectively connected to and inclined relative to a bottom surface of the first light guide layer.
Implementation Method 2
The display beam enters the optical waveguide element via the light entrance portion, and is transmitted to a display area via the light exit portion. Since the display beam is split continuously while passing through the first light guide layer, the second light guide layer, and the third light guide layer, the sectional area of the display beam is enlarged.
Data Source
AI summary
An optical waveguide element including a light entrance portion and a light exit portion is provided. The light entrance portion includes a first light guide layer, a second light guide layer, and at least one third light guide layer. Light entrance surfaces of the first light guide layer and the second light guide layer jointly compose a first inclined surface. Light exit surfaces of the first light guide layer and the second light guide layer jointly compose a second inclined surface. The first inclined surface and the second inclined surface are inclined relative to a bottom surface of the first light guide layer. The thickness of the light exit portion is less than the total thickness of the first light guide layer, the second light guide layer, and the at least one third light guide layer. A display device is also provided.