Windshield Half Mirror Gradient Reflection for HUD Glare Control
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Solution Overview
Problem
Conspicuous boundaries between half mirrors and non-half mirror regions on windshields in Head-Up Displays (HUDs) can distract drivers, and the full windshield coverage leads to glare issues due to reflected light.
Innovation Solution
A half mirror configuration for windshields featuring a cholesteric liquid crystal layer with infrared reflection regions, mixed regions, and visible light reflection regions, where the area of visible light reflection is gradually increased towards the lower side, suppressing glare and making boundaries inconspicuous.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the half mirror is provided only on the lower side of the windshield, then the display function is achieved, but a conspicuous boundary is created that disturbs driving
Solution Approach 1:
The patent applies local quality by creating different reflection characteristics in different regions of the windshield. The lower side has a half mirror function for HUD display, while the upper side has a different reflection characteristic that matches the sky, eliminating the conspicuous boundary while maintaining the display function in the required region.
2Object-affected harmful factors
If the half mirror is provided throughout the whole surface of the windshield, then the boundary problem is solved, but glare occurs due to reflected light
Solution Approach 1:
The patent applies local quality by creating different reflection characteristics in different regions of the windshield. The lower side has a half mirror function for HUD display, while the upper side has a different reflection characteristic that matches the sky, eliminating the conspicuous boundary while maintaining the display function in the required region.
Solution Approach 2:
The patent converts the harmful glare effect into a beneficial camouflage effect. By making the upper side of the windshield reflect light in a way that matches the sky background, the reflection that would normally be harmful is transformed into a useful camouflage that makes the windshield boundary invisible.
3Adaptability or versatility
If the half mirror is provided only on the lower side of the windshield, then the HUD display function is achieved, but the boundary between half mirror and non-half mirror regions becomes obtrusive
Solution Approach 1:
The patent applies local quality by creating different reflection characteristics in different regions of the windshield. The lower side has a half mirror function for HUD display, while the upper side has a different reflection characteristic that matches the sky, eliminating the conspicuous boundary while maintaining the display function in the required region.
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 glare and conceals the boundary between reflection and non-reflection regions, enhancing driver visibility and safety by minimizing distractions from reflected light.
Implementation Method 1
a reflection layer which has an infrared reflection region which selectively reflects infrared rays, a mixed region in which an area of portions which selectively reflect visible light is gradually increased toward the lower side
Implementation Method 2
a half mirror configuration for windshields featuring a cholesteric liquid crystal layer with infrared reflection regions, mixed regions, and visible light reflection regions
Data Source
Figure 1
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AI summary
Provided is a half mirror which is used for a windshield constituting a head up display, and in which a feeling of glare is suppressed, and a boundary between a region which selectively reflects visible light and a region which reflects visible light is made inconspicuous. The half mirror has a reflection layer including a non-reflection region which does not reflect visible light, a reflection region which selectively reflects visible light, and a mixed region which is provided between the regions and in which a non-reflection portion which does not reflect visible light and a reflection portion which selectively reflects visible light are mixed, and in the mixed region, an area of the reflection portion is gradually increased from the non-reflection region toward the reflection region.