Optical Combination Device for AR Eyebox Expansion
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Solution Overview
Problem
Existing augmented reality display systems, such as head-up displays and smart glasses, face challenges in maintaining a sharp image projection across eye movements and achieving high-resolution images due to limited eyebox size and optical complexity.
Innovation Solution
An optical combination device with multiple functional regions in two layers, where the first layer transmits and propagates a beam partially along the direction of the layers to the second layer, allowing for flexible and accurate optical functions, including reflection and transmission, to create multiple eyeboxes at different distances, enhancing image clarity and resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a holographic combining element is used to deflect light onto the pupil, then the image can be projected onto the eye, but the eyebox size is limited and optical complexity increases
Solution Approach 1:
The optical combination device is divided into multiple functional regions (first and second functional regions) that are spatially separate from one another. Each functional region handles specific beam propagation paths, allowing the system to manage complex optical functions through modular, segmented regions rather than a single complex holographic element.
Solution Approach 2:
The patent introduces a third dimension by propagating the beam at least partially along the direction of extent of the layers (intra-layer propagation) rather than only in the vertical direction between layers. This multi-directional beam propagation enables multiple eyeboxes at different distances and resolves the contradiction by distributing optical complexity across spatial dimensions.
2Area of stationary object
If multiple holographic layers are used to direct light to viewing locations, then the eyebox can be enlarged, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The optical combination device nests multiple functional regions within a compact layered structure. The first and second functional regions are integrated into two layers spaced apart at a distance, with the beam propagating through both layers to create multiple eyeboxes. This nested arrangement enlarges the effective eyebox while maintaining a compact form factor that simplifies manufacturing compared to distributed separate components.
3Adaptability or versatility
If the beam is propagated along the direction of extent of the layers, then multiple eyeboxes at different distances can be created, but the device length increases
Solution Approach 1:
The patent utilizes the lateral dimension (direction of extent of the layers) for beam propagation to create multiple eyeboxes at different distances. By propagating the beam along the direction of extent of the layers rather than only in the vertical direction, the system achieves adaptability to eye movements and creates multiple viewing locations without proportionally increasing the overall device length in the vertical direction.
4Reliability
If spatially separate functional regions are used to prevent crosstalk, then projection reliability improves, but the manufacturing precision requirements increase
Solution Approach 1:
The optical combination device segments the functional regions (first and second functional regions) to be spatially separate from one another, preventing crosstalk between different beam paths. This segmentation improves projection reliability by ensuring that light intended for one eyebox does not interfere with other eyeboxes, while the clear spatial separation provides manufacturing tolerances that are more manageable than tighter integrations.
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
This solution enables the creation of larger eyeboxes that adapt to eye movements, ensuring sharp image projection and higher resolution while maintaining a compact and cost-effective optical design, preventing crosstalk and enhancing projection reliability.
Implementation Method 1
the first and second layers being formed to transmit a portion of the beam incident to the first functional region in the direction of the second layer and to propagate the transmitted portion between the first and second layers at least partially along a direction of extent of the at least two layers
Implementation Method 2
the first layer having at least two functional regions, and a first functional region and a second functional region of the at least two functional regions being spatially separate from one another
Data Source
AI summary
An optical combination device for projecting an image onto an impingement region. The device includes at least a first and a second layer which are mutually spaced apart at a distance. The first layer has a shorter distance to the impingement region than the second layer. The first layer has at least two functional regions which are mutually spatially separate. The first and the second layers are formed to transmit a portion of the beam, which is incident on a first functional region, in the direction of the second layer, and to propagate the transmitted portion between the first and second layers at least partially along a direction of extent of the at least two layers, and to provide the at least partially propagated beam as outgoing beam in the direction of the impingement region via a second functional region of the first layer.