Wavelength-Selective Optical Waveguide to Reduce HUD Glare
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Solution Overview
Problem
Conventional head-up displays suffer from glare due to stray light reflections, particularly in environments with sunlight, which can impair image perception and pose safety risks.
Innovation Solution
An optical waveguide system with multiple partial waveguides optimized for different wavelengths, each equipped with an optical filter to allow only specific narrowband wavelengths to penetrate, reducing stray light reflections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If multiple partial optical waveguides are used for different wavelengths, then color representation is improved, but stray light reflections and glare increase
Solution Approach 1:
The optical waveguide is divided into multiple partial optical waveguides, each optimized for a specific wavelength range (e.g., red, green, blue). Each partial waveguide contains wavelength-selective diffraction gratings that guide only their designated wavelength, preventing cross-contamination of wavelengths that would cause glare and improving color purity.
Solution Approach 2:
Different regions of the optical waveguide have different optical properties tailored to specific wavelengths. Each partial waveguide has its own diffraction grating structure and optical characteristics optimized for its assigned color channel, allowing selective guidance and filtering of wavelengths to reduce stray light while maintaining color representation.
2Loss of energy
If the optical waveguide is optimized for one wavelength, then guidance efficiency is improved, but multi-color representation becomes difficult
Solution Approach 1:
The single optical waveguide is segmented into multiple partial waveguides, each optimized for a specific wavelength. This segmentation allows each partial waveguide to maintain high guidance efficiency for its designated wavelength while the combination of all partial waveguides enables multi-color representation.
Solution Approach 2:
The optical waveguide system is designed to perform multiple functions simultaneously - each partial waveguide guides a specific wavelength with high efficiency, and collectively they enable full-color display. The diffraction gratings in each partial waveguide are designed to be wavelength-selective, allowing the system to handle multiple colors while maintaining optimal guidance for each.
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 significantly reduces glare from sunlight, enabling safer and clearer virtual image display by minimizing the transmission of unwanted light wavelengths.
Implementation Method 1
each equipped with an optical filter to allow only specific narrowband wavelengths to penetrate, reducing stray light reflections
Implementation Method 2
The light that is coupled into the optical waveguide and carries the image information undergoes total internal reflection at the interfaces thereof and is thus guided within the optical waveguide
Implementation Method 3
a first light-incidence-side diffraction grating that diffracts incident light to cause the diffracted light to enter the optical waveguide
Data Source
AI summary
The disclosure relates to an optical waveguide for a display device and to a device for generating a virtual image using such an optical waveguide. The optical waveguide has two or more partial optical waveguides adapted to different wavelengths. At least one of the partial optical waveguides in this case has an optical filter. The optical filter is adapted to the wavelengths used.