Silicon Waveguide Display for High-Resolution Head-Mounted Applications
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Solution Overview
Problem
Current technologies fail to provide small, high-resolution, and bright displays suitable for helmet-mounted, eyeglass-mounted, or head-mounted applications, as well as projection viewing, especially requiring efficient light processing and pixel intensity control for high dynamic range color imagery.
Innovation Solution
The use of waveguide components, such as Bragg Gratings and Mach-Zehnder Interferometers, to create a display system that processes light for high-resolution color imagery, allowing for pixel-by-pixel intensity control and spectral modulation, enabling applications like head-up displays and structured light imaging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional display technologies are used, then display area can be made small, but resolution and brightness are insufficient for head-mounted applications
Solution Approach 1:
The display is segmented into an array of independently controllable micropixels, each acting as a separate light source. This segmentation allows for high resolution while maintaining compact size, as each micropixel can be precisely controlled for intensity and timing
Solution Approach 2:
The patent replaces conventional mechanical display structures with a waveguide-based optical system. Light from LED sources is guided through waveguides and modulated by micropixel arrays to create the display image, eliminating the need for large mechanical display components
2Manufacturing precision
If waveguide components are used for light processing, then resolution and brightness improve, but device complexity increases
Solution Approach 1:
Multiple waveguide components (waveguides, Bragg gratings, Mach-Zehnder interferometers) are merged into an integrated photonic circuit structure. This consolidation reduces the number of discrete components and simplifies manufacturing while maintaining precise light control capabilities
Solution Approach 2:
The waveguide components are designed to perform multiple functions: light guidance, modulation, and spectral control. The Mach-Zehnder interferometers, for example, simultaneously control intensity and enable color rendering, reducing the need for separate components
3Loss of information
If high-resolution color display is achieved, then image quality improves, but cost of fabrication increases
Solution Approach 1:
The patent uses parameter changes in the photonic circuit design to achieve cost-effective manufacturing. By optimizing waveguide dimensions, Bragg grating periods, and interferometer geometries, the system achieves high-resolution color display using standard silicon fabrication processes
Solution Approach 2:
The patent employs digital-to-analog conversion to generate display signals, creating precise intensity control for each micropixel. This digital control approach allows for high-fidelity color rendering while using cost-effective CMOS fabrication techniques
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 approach enables the development of compact, high-resolution displays and projectors that can operate across various spectral bands, providing simultaneous scene and instrument data viewing, while maintaining cost-effectiveness through silicon-based photonic circuit fabrication.
Implementation Method 1
Input and output Bragg Gratings are used to couple light into and out of the waveguide
Implementation Method 2
Mach-Zehnder Interferometers are used to control the intensity of light for each pixel
Implementation Method 3
Waveguide conveys light to each pixel in the display
Data Source
AI summary
This disclosure describes implementation of a display with resolution of one to ten million color pixels per square inch of display area. Fabrication in a CMOS foundry uses silicon waveguide technology. Red, green, and blue light are distributed via waveguide to all display pixels. Optical modulators in each pixel control image color and luminance. A photo diode is incorporated into each display pixels to enable uniformity correction of pixel luminance and color.