Optical Stack Integration for Imperceptible Embedded Eye-Tracking Components
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Solution Overview
Problem
Electronic and non-electronic components with different optical properties from surrounding elements in wearable devices cause visible distractions due to reflections and refractions, disrupting the optical integrity and creating noticeable artifacts.
Innovation Solution
Embedding components within optical stacks using substrates with matching refractive indices and light routing structures to minimize visible reflections and refractions, such as Fresnel lenses and ITO conductive materials, while maintaining optical transparency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If electronic and non-electronic components are placed in cavities bored out of optical elements or attached to their outer surfaces, then device functionality is achieved, but visible distractions and artifacts are created due to reflections and refractions at media interfaces
Solution Approach 1:
A substrate with refractive index matching materials is introduced as an intermediary between the optical element and the embedded component. This substrate acts as a mediator that eliminates the air gap interface, preventing reflections and refractions that would otherwise occur at the boundary between optical elements and components with different optical properties.
Solution Approach 2:
The patent applies homogeneity by using materials with matching refractive indices for the substrate and surrounding optical elements. This creates optical uniformity across the interface, making the embedded component invisible to the viewer while maintaining its functional presence within the optical stack.
2Device complexity
If holes or cavities are drilled in optical elements to house components, then component integration is achieved, but optical element integrity is disturbed and microcracks are created
Solution Approach 1:
The substrate is prepared in advance with recesses or cavities designed to accommodate components. This preliminary structuring allows components to be integrated without requiring post-manufacturing drilling or drilling into finished optical elements, thereby preserving optical element integrity while achieving component integration.
3Ease of manufacture
If components are attached to outer surfaces of optical elements, then device assembly is simplified, but air gaps are created causing extraneous reflections and refractions
Solution Approach 1:
The substrate serves as an intermediary layer between optical elements and attached components, eliminating air gaps. By designing the substrate with refractive index matching materials and incorporating recesses, the patent enables simple component attachment while preventing the formation of air gaps that would cause optical artifacts.
4Adaptability or versatility
If components with different optical properties are embedded in optical stacks, then functional requirements are met, but optical transparency and clarity are compromised
Solution Approach 1:
The patent applies homogeneity by using substrate materials with refractive indices that match the surrounding optical elements. This creates optical uniformity that allows embedded components to fulfill functional requirements while remaining optically invisible, thereby preserving optical transparency and clarity.
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
Prevents visible distractions by ensuring seamless integration of components within the optical path, maintaining clear vision and reducing glare, shadowing, and extraneous reflections.
Implementation Method 1
As the optical elements and the airgaps between the components and the optical elements can have very different refractive indexes, extraneous reflections and refractions occurring at media interfaces/transitions cause these components or their presences easily noticeable
Implementation Method 2
Embedding components within optical stacks using substrates with matching refractive indices and light routing structures to minimize visible reflections and refractions, such as Fresnel lenses
Implementation Method 3
Embedding components within optical stacks using substrates with matching refractive indices and light routing structures to minimize visible reflections and refractions, such as Fresnel lenses and ITO conductive materials, while maintaining optical transparency
Data Source
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AI summary
A wearable device includes circuitry on substrate. The substrate is coupled to an optical element in an optical stack. A refractive index of the substrate perceptually matches a refractive index of the optical component. The circuitry is imperceptible to the viewer wearing the device, despite that the circuitry has a view of (or, as an example, an unobstructed line of sight to) the viewer's eye. The circuitry can include a camera or an emitter, or both. The camera captures one or more reflections of the emitter from the viewer's eye. In a specific embodiment, the substrate includes a waveguide, Fresnel lenses, or lens to bend light rays around from the circuitry to achieve the imperceptibility. In alternative embodiment, the circuitry can be a piezoelectric device, liquid crystal controller, or any electronic circuitry relevant for a wearable device.