Glazing Unit with P-Polarized Coating for HUD Ghost-Free Display
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Solution Overview
Problem
Existing HUD systems face issues with exterior light interference, unsuitable coating colors, fingermark enhancement, and double images due to light reflection in transparent windshield displays.
Innovation Solution
A glazing unit with a display area having a light transmittance ≤30% and a primary p-polarized light reflective coating, which effectively reflects information data projected from a light source projecting at least 50% p-polarized light outside the driver's field of view.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a transparent pane is used as display area for HUD, then light transmission is maintained, but double images are created due to light reflection at the air/glass interface
Solution Approach 1:
The patent extracts the problematic air/glass interface by replacing air with a liquid having a refractive index matched to glass. This eliminates the refractive index mismatch that causes double images, while preserving the transparency of the display area.
Solution Approach 2:
The patent introduces a liquid as an intermediary substance between the glass surfaces. This liquid acts as a mediator that optically couples the glass layers together, preventing light reflection and double image formation while maintaining light transmission.
2Power
If a coating is applied on the interior side of the windshield, then display reflectivity is improved, but unsuitable colors are displayed affecting aesthetics from outside
Solution Approach 1:
The patent applies different optical properties to different regions: the display area has high reflectivity for p-polarized light, while the peripheral areas maintain aesthetic appearance. The liquid-filled region provides localized optical enhancement without affecting the overall aesthetic of the windshield.
Solution Approach 2:
The patent uses a liquid with specific optical properties that reflect p-polarized light without introducing unwanted colors. The liquid's refractive index matching eliminates chromatic aberrations and color distortions, providing neutral reflection that preserves aesthetic appearance.
3Power
If a coating is applied on the interior side of the windshield, then display functionality is enhanced, but fingermarks are enhanced providing bad perception
Solution Approach 1:
The patent removes the traditional coating layer that amplifies fingermark visibility and replaces it with a liquid filling the gap between glass layers. This liquid provides the necessary optical functionality without creating the same visual amplification effect for fingermarks.
4Loss of information
If exterior light interference is reduced for better display visibility, then display clarity is improved, but light transmission to driver is reduced
Solution Approach 1:
The patent creates localized optical enhancement only in the display area where the liquid is filled, while leaving the rest of the windshield transparent. This allows the driver to see clearly through the majority of the windshield while receiving enhanced display information in the specific display region.
Solution Approach 2:
The patent applies the liquid filling approach partially, only in the display area, rather than throughout the entire windshield. This partial application provides sufficient display clarity improvement without excessively reducing overall light transmission to the driver.
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 provides clear and ghost-free image reflection, reducing external light interference and enhancing driving safety by maintaining a sharp image without compromising the aesthetic appearance from outside.
Implementation Method 1
a primary p-polarized light reflective coating, which effectively reflects information data projected from a light source projecting at least 50% p-polarized light
Implementation Method 2
the light reflection at the interface between the inner pane and the liquid is reduced
Data Source
AI summary
A glazing unit having at least a first area and a second area, including an outer pane having a first surface and a second surface, and an inner pane having a first surface and a second surface, both panes bonded by an interlayer providing contact between the first surface of the inner pane and the second surface of the outer pane, where the first area is a display area having a light transmittance <30%, the display area being provided with a primary p-polarized light reflective coating, and to a head up display (HUD) using the glazing unit.