Curved Optical Waveguides for Wearable Heads-Up Displays
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current wearable heads-up displays face challenges in achieving a sleek, inconspicuous form factor and fashion appeal due to bulky planar waveguides, which restrict their adoption in consumer markets.
Innovation Solution
The integration of curved optical waveguides with holographic optical elements and dedicated in-coupling and out-coupling regions, allowing light signals to propagate through total internal reflection constraints, enabling a more aesthetically pleasing and versatile design for wearable heads-up displays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If planar waveguides are used in wearable heads-up displays, then optical performance is achieved, but the device becomes bulky and loses fashion appeal
Solution Approach 1:
The patent applies curvature to the waveguide structure, transitioning from planar to curved geometries. The curved waveguide allows light propagation while reducing the overall volume and achieving a sleeker form factor that resembles traditional eyeglass lenses, thereby resolving the contradiction between optical performance and compact size.
Solution Approach 2:
The patent introduces curvature as an additional dimensional aspect to the waveguide design. By curving the waveguide along the optical path, it achieves three-dimensional light routing that maintains optical performance while minimizing the device's footprint and achieving a more aesthetic appearance.
2Reliability
If planar waveguides are used in wearable heads-up displays, then light propagation is achieved, but the device appears unnatural compared to traditional eyeglass lenses
Solution Approach 1:
The curved waveguide design mimics the natural curvature of traditional eyeglass lenses, making the device appear more aesthetic and less bulky. The curvature allows the waveguide to follow the contour of the lens while maintaining effective light propagation through total internal reflection.
3Shape
If curved waveguides are used, then a streamlined appearance is achieved, but manufacturing complexity increases
Solution Approach 1:
The patent combines the waveguide structure with the lens substrate, integrating the optical routing function directly into the lens material. This merging reduces the number of separate components and simplifies manufacturing, as the curved waveguide can be formed as part of the lens fabrication process rather than as a separate assembly step.
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 allows for the creation of wearable heads-up displays with a more streamlined appearance, accommodating prescription lenses and enhancing optical performance while maintaining effective light propagation, thus addressing the limitations of traditional waveguide designs.
Implementation Method 1
A conventional optical waveguide operates under the principle of total internal reflection (TIR). TIR occurs when light remains in a first medium upon incidence at a boundary with a second medium because the refractive index of the first medium is greater than the refractive index of the second medium and the angle of incidence of the light at the boundary is above a specific critical angle
Data Source
AI summary
Systems, devices, and methods for optical waveguides that are well-suited for use in wearable heads-up displays (WHUDs) are described. An optical waveguide includes a volume of optically transparent material, a first holographic optical element (HOE) and a second holographic optical element, wherein the first HOE and the second HOE are carried by the volume of optically transparent material, and the first HOE is positioned across a width of the volume of optically transparent material from the second HOE. Light enters the optical waveguide and is propagated down a length of the waveguide by reflection between the first HOE and the second HOE. Propagation of the light within the optical waveguide does not require total internal reflection. The optical waveguide may include means to in-couple the light into the waveguide and means to out-couple the light from the waveguide. WHUDs that employ such optical waveguides are also described.