HUD Diffuser Angle and Curved Mirror Layout for Sunlight Stray Light
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Solution Overview
Problem
Existing head-up display systems suffer from stray light caused by external sunlight, which degrades the display of image content.
Innovation Solution
A head-up display system that includes a picture generating module with a curved mirror and a diffuser, where the curved mirror controls the light angle and angle distribution of the image beam to ensure it is incident on the diffuser in a specific direction, and the diffuser has a non-zero included angle relative to this direction, effectively deflecting external sunlight away from the image path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the diffuser is positioned perpendicular to the image beam direction, then the image beam can be uniformly distributed, but external sunlight will enter the optical system and form stray light
Solution Approach 1:
The patent applies asymmetry by setting the diffuser surface at a non-zero included angle relative to the image beam direction. This asymmetric positioning allows the diffuser to uniformly distribute the image beam while simultaneously blocking external sunlight from entering the optical system along the image path, thus resolving the contradiction between brightness uniformity and stray light reduction.
Solution Approach 2:
The patent applies local quality by optimizing the specific angular relationship between the diffuser surface and the image beam direction. By carefully selecting the non-zero included angle, the system achieves uniform light distribution in the desired direction while creating a blocking geometry that prevents sunlight from entering along the image path, addressing both requirements locally at the diffuser position.
2Object-affected harmful factors
If the diffuser is positioned at a non-zero included angle relative to the image beam, then external sunlight is deflected away, but the image beam incidence angle must be precisely controlled
Solution Approach 1:
The patent employs curved mirrors with specific radii of curvature to control the image beam angle and ensure it incident on the diffuser at the required non-zero included angle. The curved surfaces enable precise angular control of the light path, achieving stray light reduction while maintaining proper image beam orientation through optical curvature rather than complex mechanical adjustments.
Solution Approach 2:
The patent applies parameter changes by optimizing the radii of curvature of the first and second curved mirrors, as well as their respective distances from the picture generating unit and diffuser. By adjusting these optical parameters, the system achieves the required image beam angle control to work with the non-zero included angle diffuser configuration, reducing stray light while managing optical path complexity through parameter optimization.
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 reduces stray light from external sunlight while maintaining high light utilization and achieving clear display with good brightness uniformity.
Implementation Method 1
the at least one curved mirror is disposed in a transmission path of the image beam between the picture generating unit and the diffuser, and is configured to control at least one of a light angle and an angle distribution of the image beam incident on the diffuser
Implementation Method 2
the image beam is incident on the light incident surface of the diffuser, and is transmitted to the transmissive-reflective element after being uniformed by the diffuser
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
A head-up display system is adapted to transmit an image beam to a transmissive-reflective element and includes a picture generating module. The picture generating module includes a picture generating unit, at least one curved mirror, and a diffuser. The picture generating unit is configured to generate the image beam. The diffuser has a light incident surface. The curved mirror is disposed in a transmission path of the image beam between the picture generating unit and the diffuser to control at least one of a light angle and an angle distribution of the image beam incident on the diffuser, so that the image beam is incident on the light incident surface in a first direction, and is transmitted to the transmissive-reflective element after being uniformed by the diffuser. A normal direction of the light incident surface has a first included angle relative to the first direction.