AR Near-Eye Display Optical Stack UV IR Protection
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Solution Overview
Problem
Near-eye display devices, particularly augmented reality (AR) glasses, face damage from ultraviolet (UV) and infrared (IR) light exposure, leading to performance reduction and potential harm to users, as these wavelengths can cause molecular changes and heat build-up, especially when focused by optical elements.
Innovation Solution
Incorporating protective coatings such as photochromic coatings or ultraviolet (UV) and infrared (IR) blocking materials on the optical stack assembly surfaces to mitigate exposure, and using nanoimprint lithography for fabricating gradient height, slanted waveguide structures to enhance optical performance and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If optical elements are used to focus light in AR displays, then image quality and brightness are improved, but damage from UV and IR light exposure increases
Solution Approach 1:
The patent introduces protective coating layers as intermediary elements between the optical elements and the harmful UV/IR light. These coatings act as mediators that allow visible light to pass through for image display while blocking harmful UV and IR wavelengths, thus resolving the contradiction between maintaining image quality and preventing light-induced damage.
Solution Approach 2:
The patent converts the harmful UV and IR light into a beneficial filtering opportunity by designing coatings that specifically target these wavelengths. The harmful radiation is transformed from a damaging factor into a controlled filtering process, where the coatings selectively block harmful wavelengths while maintaining transmission of beneficial visible light for display purposes.
2Object-affected harmful factors
If photochromic coatings are applied to block UV light, then protection against UV damage is improved, but visibility and optical clarity may deteriorate
Solution Approach 1:
The patent applies different functional properties to different parts of the optical system by using specialized protective coatings on specific optical elements. Each coating is tailored to the local requirements of the optical element it protects, ensuring UV blocking where needed while maintaining optical clarity in visible light transmission paths. This localized application resolves the contradiction between protection and visibility.
3Manufacturing precision
If conventional lithography is used for waveguide fabrication, then manufacturing simplicity is maintained, but optical performance and precision are insufficient
Solution Approach 1:
The patent replaces conventional mechanical lithography processes with nanoimprint lithography technology. This substitution enables precise fabrication of waveguide structures with controlled height gradients and slanted surfaces that are difficult to achieve with traditional methods. The nanoimprint process uses molecular-level precision to create the required optical structures, resolving the contradiction between manufacturing precision and process complexity.
4Manufacturing precision
If uniform height waveguide structures are used, then manufacturing is simpler, but optical performance and light coupling efficiency are reduced
Solution Approach 1:
The patent implements local quality by creating waveguide structures with varying height profiles instead of uniform heights. The height gradient is specifically designed to optimize light coupling efficiency at different positions within the waveguide. This localized variation in structure height improves optical performance while the nanoimprint fabrication process maintains manufacturing feasibility through a single-step imprinting operation.
Solution Approach 2:
The patent transitions from two-dimensional uniform waveguide structures to three-dimensional gradient height structures. By introducing the height dimension as a variable parameter, the waveguide can optimize light coupling and propagation characteristics. The slanted and graded height profiles add a third dimension to the waveguide geometry, enabling superior optical performance while the nanoimprint process efficiently handles this dimensional complexity.
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 protective coatings effectively prevent damage from UV and IR light, extending the product life and maintaining performance, while the gradient waveguide structures improve optical performance and reduce manufacturing costs.
Implementation Method 1
ultraviolet (UV) and infrared (IR) blocking material
Implementation Method 2
ultraviolet (UV) and infrared (IR) blocking material
Implementation Method 3
photochromic coating
Data Source
AI summary
A display element of an optical stack assembly in an augmented reality (AR) near-eye display device may be protected against ultraviolet (UV) and/or infrared (IR) exposure through one or more protective coatings on various surfaces of the elements of the optical stack assembly. A photochromic coating on one of the surfaces of the elements of the optical stack assembly may also be used instead of or in addition to the protective coatings.