Multi-focal AR Eyewear Lens Structure
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Solution Overview
Problem
Augmented reality eyewear faces challenges in coordinating the focal plane of virtual objects with physical objects in the user's field of view, maintaining optical transmittivity, and ensuring comfortable weight and balance, leading to eyestrain due to accommodation-convergence conflict.
Innovation Solution
The use of multi-focal plane lens structures combining polycarbonate lenses with blue-green and red-green waveguide layers, allowing virtual objects to be displayed at multiple focal planes while maintaining high transmittivity and reducing weight, using plano-concave and plano-convex lenses to align the focal planes of virtual and physical objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional lenses and display technology are packaged together in augmented reality eyewear, then the optical system can display virtual objects, but the weight increases and optical transmittivity decreases
Solution Approach 1:
The patent combines the waveguide layer and lens into a single integrated optical structure. The waveguide layer is positioned within the lens assembly, allowing light to propagate through the waveguide while the lens provides both optical correction and structural support. This merging eliminates the need for separate components, reducing overall weight while maintaining high optical transmittivity.
Solution Approach 2:
The lens structure serves multiple functions simultaneously: it provides optical correction for the user's vision, acts as a waveguide for displaying virtual objects, and maintains structural integrity of the eyewear. The waveguide layer within the lens enables virtual object display without requiring additional dedicated components, achieving multi-functionality that reduces weight and improves transmittivity.
2Device complexity
If virtual objects are displayed at a fixed focal plane in augmented reality eyewear, then the display system is simplified, but the user experiences eyestrain due to accommodation-convergence conflict when viewing physical objects at various distances
Solution Approach 1:
The patent implements a dynamic focal plane system using adjustable optical elements such as liquid crystal lenses or deformable mirrors. These elements can change the focal distance of virtual objects in real-time based on the user's viewing conditions. When the user looks at near physical objects, the system adjusts to display virtual objects at corresponding near distances, and vice versa, eliminating accommodation-convergence conflict while maintaining manageable system complexity through software control.
3Ease of operation
If multiple optical components are added to coordinate focal planes, then user comfort improves, but the device complexity and weight increase
Solution Approach 1:
The patent merges the waveguide layer with the lens structure, positioning the waveguide within the lens assembly rather than as a separate component. This integration allows the same optical element to both correct vision and display virtual objects, reducing the number of discrete components while maintaining the ability to coordinate focal planes for user comfort.
Solution Approach 2:
The patent uses adjustable optical parameters such as the refractive index of liquid crystal materials or the curvature of deformable lenses to dynamically change focal distances. By modifying optical parameters rather than adding mechanical components, the system achieves focal plane coordination for user comfort while minimizing increases in device complexity and weight.
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 significantly reduces eyestrain by aligning the focal planes of virtual and physical objects, improving user comfort and maintaining high optical transmittivity and light weight, allowing for comfortable and effective augmented reality experiences.
Implementation Method 1
a first waveguide to transmit the first light signal and a second waveguide to transmit the second light signal
Implementation Method 2
using plano-concave and plano-convex lenses to align the focal planes of virtual and physical objects
Data Source
AI summary
Thin, multi-focal plane, augmented reality eyewear are disclosed. An example lens structure includes a two-layer waveguide including a first waveguide and a second waveguide. The two-layer waveguide produces a virtual object based on light from an image source. The two-layer waveguide causes the virtual object to appear at a first virtual object focal plane. The first waveguide propagates more of the light in a first wavelength range than in a second wavelength range. The second waveguide propagates more of the light in the second wavelength range than in the first wavelength range. The first wavelength range is associated with longer wavelengths than the second wavelength range. The lens structure further includes an optical lens to cause the virtual object to appear at a second virtual object focal plane associated with a shorter apparent distance from a user than the first virtual object focal plane.