Waveguide Embedded Mirrors for AR Field of View
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Solution Overview
Problem
Conventional near-to-eye optical systems in head-mounted displays suffer from limited field of view and bulkiness due to the use of mirrors and lenses, which restrict their practical applications in augmented reality and other fields.
Innovation Solution
A waveguide with embedded mirrors is used to guide and reflect light, allowing for a larger field of view by employing in-coupling and out-coupling mirrors oriented at oblique angles for total internal reflection and metallic reflective coatings, enabling the superimposition of computer-generated images over real-world vision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If conventional mirrors and lenses are used in near-to-eye optical systems, then the system can display images, but the field of view is limited and the system becomes bulky
Solution Approach 1:
The patent embeds mirrors directly within the waveguide structure, nesting the reflective elements inside the optical pathway rather than using separate external mirrors. This integration allows the mirrors to be positioned close to the eye while maintaining a compact overall form factor, thereby expanding the field of view without increasing system bulkiness
Solution Approach 2:
The patent transitions from using traditional lens-based optical paths to a waveguide-based planar optical path. By utilizing total internal reflection within the waveguide planes and embedding mirrors at strategic locations, the system achieves a larger field of view in a two-dimensional integrated structure rather than relying on three-dimensional lens assemblies
2Ease of manufacture
If conventional optical systems are used, then images can be displayed, but the cost is high
Solution Approach 1:
The patent replaces conventional lens-based optical systems with a waveguide-based system that uses total internal reflection and embedded mirrors. This substitution eliminates the need for precision lens alignment and complex mechanical assemblies, thereby reducing manufacturing costs while maintaining reliable optical performance through the robust waveguide structure
Solution Approach 2:
The patent changes the fundamental optical parameters by using total internal reflection within the waveguide rather than refraction through lenses. This parameter change from refractive optics to reflective waveguide optics simplifies the manufacturing process and reduces costs while preserving the essential function of image display
3Area of stationary object
If mirrors are embedded in waveguide, then field of view increases, but manufacturing precision requirements increase
Solution Approach 1:
The patent utilizes total internal reflection at the waveguide interfaces, which occurs automatically based on the waveguide's refractive index and geometry without requiring precise mirror alignment. The embedded mirrors only need to be positioned at general locations rather than with high precision, as the waveguide structure itself provides the self-aligning optical pathway through total internal reflection
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 system enhances the field of view to potentially 45 degrees, allowing for more effective display of augmented reality and improved user experience by maintaining a one-to-one relation of input to output light angles, while maintaining transparency for real-world image visibility.
Implementation Method 1
employing in-coupling and out-coupling mirrors oriented at oblique angles for total internal reflection
Implementation Method 2
employing in-coupling and out-coupling mirrors oriented at oblique angles
Data Source
AI summary
A waveguide with embedded mirrors includes an in-coupling region for receiving input light into the waveguide and an out-coupling region for emitting output light from the waveguide. The mirrors include a plurality of in-coupling mirrors disposed within the in-coupling region of the waveguide and orientated to reflect the input light down the waveguide towards the out-coupling region as guided light. The mirrors further include a plurality of out-coupling mirrors disposed within the out-coupling region of the waveguide and orientated to reflect the guided light out of the waveguide as the output light.