Dual-Index Waveguide Stack for Bright, Low-Crosstalk Virtual Images
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Solution Overview
Problem
Conventional image light guide arrangements face challenges in achieving desired virtual image brightness and resolution while managing bulk and cost, with limitations in diffraction and propagation of certain wavelengths of light.
Innovation Solution
An image light guide system comprising a first and second waveguide with in-coupling and out-coupling diffractive optics, each optimized for specific wavelength ranges, allowing angularly encoded and decoded light propagation to enhance brightness and resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional image light guide arrangements are used to reduce bulk and cost, then device size and price are reduced, but image resolution and brightness are compromised
Solution Approach 1:
The patent divides the light guide system into multiple separate waveguides, each optimized for specific wavelength ranges. This segmentation allows each waveguide to be optimized for its specific function while maintaining overall system compactness, resolving the contradiction between reduced bulk and maintained image resolution.
Solution Approach 2:
Each waveguide is designed with specific local properties tailored to its wavelength range optimization. The in-coupling and out-coupling diffractive optics are strategically positioned and designed with specific local characteristics to maximize light extraction and coupling efficiency for their respective wavelength ranges, thereby maintaining high image quality despite reduced bulk.
2Volume of moving object
If conventional image light guide arrangements are used to reduce bulk and cost, then device size and price are reduced, but virtual image brightness is compromised
Solution Approach 1:
By segmenting the light guide into multiple wavelength-specific waveguides, each waveguide can be optimized for its specific wavelength range, maximizing light extraction efficiency and contributing to overall virtual image brightness while maintaining compact device size.
Solution Approach 2:
The patent employs diffractive optics with specific coupling angles and waveguide thicknesses tailored to each wavelength range. These parameter optimizations maximize light extraction efficiency for each wavelength, thereby enhancing virtual image brightness despite reduced bulk.
3Device complexity
If conventional image light guide arrangements are used, then device complexity is reduced, but diffraction and propagation of certain wavelengths are underperforming
Solution Approach 1:
The system segments the optical path into separate waveguides for different wavelength ranges, allowing each waveguide to be optimized for its specific wavelength performance. This segmentation improves wavelength-specific diffraction and propagation while maintaining manageable system complexity through modular design.
Solution Approach 2:
Each waveguide and its associated diffractive optics are designed with local quality optimizations tailored to its wavelength range. The in-coupling and out-coupling optics are specifically designed to maximize efficiency for their respective wavelengths, ensuring reliable performance across all wavelength ranges.
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 system improves polychromatic image-bearing light output intensity and reduces crosstalk between wavelength ranges, maintaining image quality and reducing bulk and cost.
Implementation Method 1
a first in-coupling diffractive optic formed along the first waveguide, wherein the first in-coupling diffractive optic is arranged to diffract image-bearing light beams of a first wavelength range into the first waveguide in an angularly encoded form
Implementation Method 2
An optical image light guide may convey image-bearing light to a viewer in a narrow space for directing the virtual image to the viewer's pupil
Data Source
AI summary
An image light guide system for conveying a virtual image that includes a first waveguide having a first refractive index and a second waveguide having a second refractive index. The first waveguide includes diffractive optics arranged to in-couple and out-couple image-bearing light beams of a first wavelength range. The second waveguide includes diffractive optics arranged to in-couple and out-couple image-bearing light beams of at least a second wavelength range. An image light guide system for conveying a virtual image that includes a first waveguide having a first refractive index and a second waveguide having a second refractive index. The first waveguide includes diffractive optics arranged to in-couple and out-couple image-bearing light beams of a first wavelength range. The second waveguide includes diffractive optics arranged to in-couple and out-couple image-bearing light beams of at least a second wavelength range.