Head-up Display Diffuser with Irregular Microlenses and Light-Blocking Mask
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Solution Overview
Problem
Existing head-up displays suffer from irritations caused by streaking light reflected from external litter onto the stray disc, which can reach the viewer's eye through the optical system, leading to discomfort.
Innovation Solution
The arrangement of focusing elements irregularly on the surface of the stray disc, combined with a light-blocking mask on the side facing the projection system, suppresses Moiré patterns and effectively reduces disruptive light interference by directing it away from the viewer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a diffuser with regular focusing elements is used in the head-up display, then light can be focused effectively onto the intermediate image plane, but Moiré patterns are generated and stray light causes irritation to the viewer
Solution Approach 1:
The patent applies asymmetry by arranging the focusing elements (microlenses) in an irregular, non-periodic pattern on the diffuser surface. This irregular arrangement breaks the symmetry that causes Moiré patterns when the diffuser pattern interacts with the projection system. The asymmetric distribution of microlenses maintains light focusing functionality while eliminating the harmful periodic interference patterns that would otherwise reach the viewer's eye
Solution Approach 2:
The patent converts the potentially harmful stray light into a beneficial effect by using the irregularly arranged focusing elements to redirect stray light away from the viewer's line of sight. The same focusing elements that could potentially concentrate stray light into irritating patterns instead dispersize it in controlled directions, transforming a harmful effect into a benefit by directing stray light away from causing irritation while maintaining image quality
2Object-affected harmful factors
If a light-blocking mask is added to block stray light, then stray light irritation is reduced, but the device complexity increases
Solution Approach 1:
The patent merges the light-blocking function directly into the diffuser component by integrating a light-absorbing layer onto the diffuser substrate. This combination eliminates the need for a separate light-blocking mask component, reducing device complexity while maintaining the stray light blocking function. The integrated structure performs both diffusion and light blocking in a single element, simplifying the overall optical system
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 solution significantly reduces irritations caused by disruptive light and Moiré patterns, ensuring that almost all light from the projection system is directed towards the mirror element and the viewer, while minimizing reflections that could cause discomfort.
Implementation Method 1
the diffuser have focusing elements on its side facing the projection system... The focusing elements focus the light coming from the projection system onto openings in the mask
Implementation Method 2
The light-blocking mask is preferably made of a light-absorbing material. This has the advantage that stray light incident toward the projection system is absorbed by the mask
Implementation Method 3
a diffuser, and a mirror element... The image on the diffuser is transformed into a virtual image
Implementation Method 4
a mirror element... the windshield of the vehicle or a so-called combiner arranged between it and the viewer serves as the mirror element
Data Source
Figure 1
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AI summary
The invention relates to a head-up display comprising a display element (1), a projection system (2), a diffusing plate (3) and a mirror element (4, 41). In such head-up displays, irritations often occur due to stray light. A head-up display that generates less irritations by incident stray light is thus desirable. It is proposed that the diffusing plate (3) has focusing elements (31) on its side facing the projection system (2) and a light-blocking mask (32) on its side facing away from the projection system (2).