Curved Waveguide Optics Using Micro Phosphor for Wide-FOV AR Displays
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Solution Overview
Problem
Current technologies face challenges in creating curved waveguides for VR/AR systems that are thin, lightweight, and provide a wide field of view due to light loss issues with Total Internal Reflection (TIR) in flat waveguides, making it difficult to achieve efficient curved waveguide-based optics.
Innovation Solution
A system utilizing a UV display and a curved waveguide with double-sided UV reflective coatings/films and an array of light wavelength converting phosphor discs covered with micro lenses, which trap UV light and convert it into visible light for wide field of view without relying on TIR.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If flat waveguide with Total Internal Reflection (TIR) is used, then light can be effectively bounced within the waveguide, but the waveguide cannot be curved and light loss occurs in curved configurations
Solution Approach 1:
The patent changes the optical parameters by introducing UV-reflective coatings with specific reflectivity characteristics (greater than 90% reflectivity for UV wavelengths) and uses UV light conversion elements with specific wavelength conversion properties to transform UV light into visible light, enabling curved waveguide operation without TIR light loss
Solution Approach 2:
The patent introduces UV-reflective coatings as intermediary elements between the UV light source and the waveguide boundaries, and uses light conversion elements as intermediaries to convert UV light into visible light that can propagate through the curved waveguide without suffering from TIR limitations
2Weight of moving object
If curved waveguide is used to achieve thin and lightweight form factor, then close form fitting is improved, but light loss increases making effective VR/AR difficult
Solution Approach 1:
The patent changes the wavelength parameter by using UV light (which can be efficiently reflected by the specialized coatings) and converts it to visible light, enabling curved waveguide operation with minimal light loss and thus achieving thin, lightweight form factors
3Loss of energy
If UV light is used with reflective coatings, then light can be trapped and converted to visible light in curved waveguide, but UV light must be prevented from reaching the user's eye
Solution Approach 1:
The patent uses light conversion elements (phosphor materials) that absorb UV light and emit visible light at different wavelengths, effectively changing the color/wavelength of the light. This ensures UV light is converted to visible light before reaching the user's eye, eliminating UV exposure while maintaining efficient light trapping
Solution Approach 2:
The light conversion elements act as intermediaries that intercept UV light within the waveguide and convert it to visible light, preventing UV light from reaching the user's eye while maintaining the benefits of UV light trapping for image projection
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
Enables the creation of a thin, lightweight, and close-form fitting VR/AR system with a wide field of view by effectively trapping and converting UV light within the waveguide, providing clear virtual images without significant distortion.
Implementation Method 1
a first ultraviolet (UV) light-reflecting coating or film disposed on the waveguide, and a second UV light-reflecting coating or film disposed on the waveguide
Implementation Method 2
at least one light wavelength conversion element such as such as a phosphor disc is in the waveguide and is disposed to receive UV light from the UV emitter reflected by the UV light-reflecting coatings and/or films
Implementation Method 3
covered with pinhole-sized micro lenses
Data Source
AI summary
A sunglasses-style head worn display includes a curved waveguide with double reflective coatings/films and containing an array of light wavelength converting phosphor pinhole-size discs covered with pinhole-sized micro lenses, presenting a wide FOV virtual image for AR/VR.