Dichroic Filters for Compact Waveguide Eyepiece Color Separation
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Solution Overview
Problem
Existing augmented reality systems lack efficient methods for color separation in eyepieces, leading to larger form factors and reduced brightness and contrast in virtual reality and augmented reality visualization systems.
Innovation Solution
The use of long-pass and short-pass dichroic filters in eyepieces for color separation between different waveguides, reducing wavelength cross-coupling and enhancing brightness and contrast.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If traditional color separation methods are used in eyepieces, then the system can function, but the form factor becomes larger
Solution Approach 1:
The patent applies parameter changes by utilizing dichroic filters with specific wavelength transmission characteristics. The filters are designed to transmit certain wavelength ranges (e.g., red, green, blue) while reflecting others, enabling compact color separation through optical parameter optimization rather than mechanical arrangement.
Solution Approach 2:
Dichroic filters serve as intermediary elements between the waveguides and the viewer's eye. These filters mediate the color separation process by selectively transmitting and reflecting different wavelength ranges, allowing multiple color channels to be combined in a compact configuration without requiring separate optical paths for each color.
2Illumination intensity
If traditional color separation methods are used in eyepieces, then the system can function, but brightness and contrast are reduced
Solution Approach 1:
The dichroic filters are engineered with specific transmission and reflection parameters optimized for different wavelength ranges. By adjusting the optical parameters of these filters (transmission bands, reflection bands, transition slopes), the system achieves enhanced brightness and contrast while maintaining compact form factor, as the filters efficiently direct light without requiring complex mechanical arrangements.
3Volume of moving object
If dichroic filters are used for color separation, then form factor is reduced and brightness/contrast are improved, but wavelength cross-coupling must be managed
Solution Approach 1:
The patent manages wavelength cross-coupling by carefully selecting and optimizing the transmission and reflection parameters of the dichroic filters. Each filter is designed with specific cutoff wavelengths and transmission bands that minimize overlap between color channels, ensuring reliable color separation while maintaining compact form factor and high brightness/contrast performance.
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 implementation of dichroic filters results in a more compact form factor and improved brightness and contrast in virtual reality and augmented reality systems.
Implementation Method 1
The use of long-pass and short-pass dichroic filters in eyepieces for color separation between different waveguides
Implementation Method 2
an image in visible light wavelengths is presented to a viewer through a waveguide
Data Source
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AI summary
An eyepiece for projecting an image to an eye of a viewer, comprising a first planar waveguide positioned in a first lateral plane, wherein the first planar waveguide comprises a first incoupling element optically coupled thereto, and wherein the first incoupling element is configured to diffract image light in a first wavelength range centered at a first wavelength; a second planar waveguide positioned in a second lateral plane adjacent the first lateral plane, wherein the second planar waveguide comprises a second incoupling element optically coupled thereto, and wherein the second incoupling element is configured to diffract image light in a second wavelength range centered at a second wavelength different from the first wavelength; and a first optical element positioned between the first planar waveguide and the second planar waveguide in lateral alignment with the first incoupling element, wherein the first optical element is configured to reflect image light in the first wavelength range.