Curved Lightguide Tiled Field of View for Head-wearable Displays
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Solution Overview
Problem
Conventional head-wearable displays (HWDs) are limited by cost, size, weight, thickness, field of view, and efficiency due to their optical systems, which restrict their practical and leisure applications.
Innovation Solution
A head-wearable display design utilizing a single microdisplay with a tiled field of view, featuring a curved light guide and a set of partially reflective surfaces that redirect display light while allowing ambient light to pass through, creating an expanded field of view and improved user experience within a thin lens encapsulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If conventional optical systems are used in HWDs, then the display function is achieved, but the field of view is limited and the device becomes bulky
Solution Approach 1:
The patent segments the field of view into multiple discrete angular positions (e.g., 0°, 45°, 90°, 135°) that can be independently displayed. Instead of providing a continuous wide field of view, the system divides the viewing space into separate zones, each optimized for specific display content, thereby expanding the total covered area without requiring a proportionally larger optical system.
Solution Approach 2:
The patent transitions from a two-dimensional display plane to a three-dimensional tiled field of view by arranging multiple display regions at different angular positions around the user's eye. This spatial arrangement in multiple dimensions allows the system to provide an expanded overall field of view while keeping each individual display element compact.
2Area of stationary object
If multiple optical components are used to expand field of view, then the field of view increases, but the device complexity and fabrication difficulty increase
Solution Approach 1:
The patent merges multiple display functions into a single integrated optical structure. The waveguide contains multiple grating structures that are fabricated as part of a unified device, eliminating the need for separate optical components for each field of view segment. This integration reduces both the number of components and fabrication complexity.
Solution Approach 2:
The waveguide structure serves multiple functions simultaneously: it guides light from the display source, contains multiple grating structures for different angular directions, and provides the optical path for all tiled field of view segments. This multi-functionality reduces the overall component count while achieving an expanded field of view.
3Volume of stationary object
If a single microdisplay is used, then the device size is reduced, but the field of view coverage is insufficient
Solution Approach 1:
The patent uses a single microdisplay but expands its effective coverage by projecting display content into multiple angular dimensions through the waveguide grating structures. The same physical display source creates virtual images at different angular positions, effectively multiplying the field of view coverage without increasing display device volume.
Solution Approach 2:
The waveguide acts as an intermediary between the single microdisplay and the user's eye. It takes the limited output from the compact microdisplay and redistributes the light into multiple angular directions using grating structures, thereby expanding the effective field of view coverage while maintaining a small device size.
4Ease of operation
If conventional see-through eyepieces are used, then the structural integrity is maintained, but the see-through characteristics and user experience are degraded
Solution Approach 1:
The patent uses a waveguide structure with grating patterns that can be integrated into thin, lightweight optical elements. These thin-film or thin-structure waveguides maintain adequate structural integrity while providing superior see-through characteristics compared to conventional thick eyepieces, enhancing user experience through better transparency and reduced weight.
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 solution enhances the field of view and user experience by reducing the number of optical components and fabrication complexities, resulting in a more efficient and cost-effective HWD with improved see-through characteristics.
Implementation Method 1
A head-wearable display design utilizing a single microdisplay with a tiled field of view, featuring a curved light guide and a set of partially reflective surfaces that redirect display light
Implementation Method 2
a set of partially reflective surfaces that redirect display light while allowing ambient light to pass through
Data Source
AI summary
Implementations are described of an eyepiece for a head wearable display. The eyepiece includes a curved lightguide for guiding display light via total internal reflection between a peripherally-located input surface and a viewing region and an output coupler disposed across the viewing region to redirect the display light towards an eyeward direction for output from the curved light guide. The output coupler has an optical axis and has a set of reflective surfaces that includes at least two individual reflective surfaces to reflect incident display light toward the eyeward direction in at least two different directions relative to the optical axis of the output coupler. Other embodiments are disclosed and claimed.