Adjustable Antireflection Slats for HUD Stray Light Control
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Solution Overview
Problem
Conventional head-up displays suffer from reduced contrast due to stray light reflections, which are not effectively mitigated by existing antireflection methods such as tilting components or using glare traps, leading to restricted viewing angles and reduced performance.
Innovation Solution
An adjustable antireflection mechanism featuring slats with resilient reinforcing elements and spacer platelets allows for variable angle settings, reducing direct impact from external forces and enabling precise control over the slat spacing and angle, thereby minimizing stray light entry and enhancing image contrast.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If antireflection coatings or structural roughness are used to reduce reflection intensity, then reflection intensity is reduced, but the contrast of the virtual image is still reduced due to remaining stray light
Solution Approach 1:
The antireflection element is segmented into multiple independently adjustable slats instead of a single fixed component. Each slat can be individually positioned to optimize stray light blocking while maintaining image contrast. This segmentation allows precise control over which reflected light paths are blocked.
Solution Approach 2:
The slats are made adjustable and movable rather than fixed, allowing dynamic optimization of their positions. The adjustment mechanism enables the slats to be positioned at different angles and locations to block stray light paths while preserving the virtual image quality, resolving the contradiction between reducing reflections and maintaining contrast.
2Object-affected harmful factors
If reflective components are tilted to redirect reflections away from the viewer's eye, then stray light is reduced, but installation space is significantly increased
Solution Approach 1:
Instead of tilting the entire reflective component in one dimension (which requires large installation space), the invention uses multiple thin slats arranged in a array. The slats can be adjusted in position and angle independently, allowing stray light to be blocked by distributing the function across multiple elements in different spatial dimensions, reducing the overall installation footprint.
3Adaptability or versatility
If the eyebox size is enlarged to provide more viewing freedom, then viewer positioning flexibility is improved, but the optical unit size must be increased
Solution Approach 1:
The optical system uses segmented slats that can be independently adjusted to expand the effective eyebox region. By positioning multiple slats at different angles and locations, the system creates multiple viewing zones that collectively provide a larger effective viewing area without requiring a proportionally larger optical unit.
4Ease of manufacture
If conventional fixed antireflection methods are used, then manufacturing is simpler, but viewing angles are restricted and performance is reduced
Solution Approach 1:
The invention introduces adjustability to the slats, transforming them from fixed to movable components. This dynamic capability allows the slats to be positioned to optimize performance for different viewing angles and conditions, significantly improving adaptability while maintaining reasonable manufacturing complexity through modular design.
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 solution effectively reduces stray light influence, allowing for a larger viewing angle and improved contrast by enabling precise adjustment of the antireflection slats, thus enhancing the user's experience in head-up displays.
Implementation Method 1
The light that is coupled into the optical waveguide undergoes total internal reflection at the interfaces of the latter and is thus guided within the optical waveguide.
Implementation Method 2
a first diffraction grating on the light-incidence side, which diffracts incident light so as to make the diffracted light enter the optical waveguide
Implementation Method 3
a first light-emergence diffraction grating, which diffracts the light that is incident from the optical waveguide
Data Source
AI summary
An apparatus for generating a virtual image having a display element for generating an image, an optical waveguide for expanding an exit pupil, and an anti-glare element arranged downstream of the optical waveguide in the beam path, wherein the anti-glare element is a shutter that has a plurality of slats which, in their end regions, have flat reinforcing elements which protrude beyond the slats is disclosed.