Dual Combiner Optical Design for Head-Wearable Displays
Solution Overview
Problem
Head-wearable display devices face challenges in providing a large eyebox with acceptable thickness and weight, limiting their compactness and user experience, especially when trying to align magnification and support a thin lightguide for efficient image delivery.
Innovation Solution
The implementation of a dual combiner configuration in head-wearable display devices, which includes a set of combiners to expand the pupil and align magnification, allowing for a larger eyebox while maintaining a thin and lightweight design by positioning the micro-display in the temple portion, using curved lightguides that support total internal reflection and polarization to reduce artifacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a large eyebox is provided to enhance field-of-view and image quality, then the device thickness and weight increase, but this compromises the compactness and portability of the head-wearable display device
Solution Approach 1:
The optical system is segmented into multiple combiners (first combiner and second combiner) positioned at different locations within the lightguide. Each combiner handles a specific portion of the light path, allowing the eyebox to be expanded through multiple reflection points rather than requiring a single thick lightguide structure. This segmentation enables large eyebox while maintaining thin overall device thickness.
Solution Approach 2:
The patent transitions from a single-plane optical path to a three-dimensional optical path by introducing multiple combiners at different positions and angles within the lightguide. The light undergoes multiple reflections at different spatial coordinates, effectively utilizing the third dimension to expand the eyebox without increasing the linear thickness of the device.
2Area of stationary object
If a large eyebox is provided to enhance field-of-view and image quality, then the device weight increases, but this compromises the portability and comfort of the head-wearable display device
Solution Approach 1:
The optical system is segmented into multiple combiners (first combiner and second combiner) positioned at different locations within the lightguide. Each combiner handles a specific portion of the light path, allowing the eyebox to be expanded through multiple reflection points rather than requiring a single thick lightguide structure. This segmentation enables large eyebox while maintaining thin overall device thickness.
Solution Approach 2:
The patent transitions from a single-plane optical path to a three-dimensional optical path by introducing multiple combiners at different positions and angles within the lightguide. The light undergoes multiple reflections at different spatial coordinates, effectively utilizing the third dimension to expand the eyebox without increasing the linear thickness of the device.
3Length of moving object
If a thin lightguide is used to maintain device compactness, then the eyebox size is limited, but this reduces the field-of-view and image quality
Solution Approach 1:
The optical system is segmented into multiple combiners (first combiner and second combiner) positioned at different locations within the lightguide. Each combiner handles a specific portion of the light path, allowing the eyebox to be expanded through multiple reflection points rather than requiring a single thick lightguide structure. This segmentation enables large eyebox while maintaining thin overall device thickness.
Solution Approach 2:
The patent transitions from a single-plane optical path to a three-dimensional optical path by introducing multiple combiners at different positions and angles within the lightguide. The light undergoes multiple reflections at different spatial coordinates, effectively utilizing the third dimension to expand the eyebox without increasing the linear thickness of the device.
4Area of stationary object
If multiple combiners are added to expand the eyebox and align magnification, then the device complexity increases, but this improves the field-of-view and image quality
Solution Approach 1:
Multiple combiners are merged into a single integrated lightguide structure. The first and second combiners are positioned within the same lightguide body, sharing common optical paths and mounting structures. This merging approach expands the eyebox through multiple reflection points while minimizing the increase in overall device complexity by utilizing a unified optical platform.
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 configuration enhances the field-of-view, image quality, and manufacturing efficiency, providing a full-color display with improved eye tracking capabilities and a larger eyebox without increasing the device's thickness or weight, thus improving user interaction in augmented and virtual reality applications.
Implementation Method 1
using curved lightguides that support total internal reflection
Implementation Method 2
using curved lightguides that support total internal reflection and polarization to reduce artifacts
Data Source
AI summary
A head-wearable display device is configured to support a plurality of combiners (e.g., at least two combiners) to expand an eyebox associated with the head-wearable display device. The plurality of combiners may expand the pupil and the head-wearable display device may be configured to align the magnification between the plurality of combiners, such that a single magnified virtual image with an expanded eyebox may be delivered to the user.