Composite HUD Windshield Coating With Heated Sensor Region
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Solution Overview
Problem
Existing laminated glass panels for HUDs with reflective coatings for p-polarized radiation face challenges in maintaining optimal optical properties for both HUD projection and sensor functionality, particularly in vehicle windshields, where heating the sensor area is complex and affects light transmission and sensor performance.
Innovation Solution
A laminated glass panel with a reflective coating that uses a single silver layer and asymmetrical dielectric layers to achieve high reflectivity for p-polarized radiation, allowing for a separate heated sensor area without compromising light transmission or sensor performance, and is compatible with vehicle windshield specifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a reflective coating is applied to the windshield for HUD projection, then HUD image intensity is improved, but sensor functionality deteriorates due to interfering reflections
Solution Approach 1:
The patent applies different optical properties to different regions of the windshield: the HUD area has a reflective coating optimized for p-polarized radiation, while the sensor area has a transparent coating that allows electromagnetic radiation to pass through. This local differentiation resolves the contradiction by providing high HUD image intensity where needed while maintaining sensor functionality in the sensor area.
2Reliability
If the sensor area is heated to clear ice and frost, then sensor reliability is improved, but light transmission deteriorates due to opacity of heating conductors
Solution Approach 1:
The patent uses a transparent heating film in the sensor area instead of opaque heating wires or printed conductors. This thin film allows light to pass through while still providing the necessary heating function to clear ice and frost, thereby maintaining both sensor reliability and light transmission.
Solution Approach 2:
The patent employs a composite coating structure in the sensor area that combines transparent conductive materials with heating functionality. This composite material provides both the optical transparency needed for light transmission and the electrical conductivity required for heating, resolving the contradiction between reliability and illumination intensity.
3Temperature
If heating conductors are placed in the sensor area, then ice and frost clearance is improved, but optical properties deteriorate due to scattering effects
Solution Approach 1:
The patent replaces traditional opaque heating conductors with a transparent heating film that can be applied to the sensor area. This film provides the necessary heating capability to clear ice and frost while maintaining optical properties by eliminating scattering effects associated with conventional conductors.
4Reliability
If the reflective coating is removed from the sensor area, then sensor functionality is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies a transparent coating specifically to the sensor area that differs from the reflective coating used in the HUD area. This local differentiation maintains sensor functionality while allowing for integrated manufacturing processes that can apply different coatings to different regions in a single production line, avoiding the need to remove and reapply coatings separately.
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 a high-intensity HUD image visible to polarization-selective sunglasses, suppresses interfering reflections for sensors, and ensures effective heating of the sensor area, maintaining good sensor functionality and compliance with vehicle manufacturer specifications.
Implementation Method 1
The electrically conductive coating is suitable for reflecting radiation from a head-up display (HUD) projector with predominantly p-polarized radiation to generate a HUD display image
Implementation Method 2
The manifold conductors are connected to opposite poles of a voltage source, so that a current path for a heating current is formed between them across the sensor area
Implementation Method 3
Through a targeted selection of the dielectric layer modules located above and below this silver layer, good reflection properties with respect to the p-polarized radiation are achieved, in particular a high average reflectance and color-neutral rendering
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
The invention relates to a composite pane (10) with a HUD region (B) and a sensor region (S). The composite pane (10) is provided with an electrically conductive coating (20) which is suitable for reflecting p-polarized radiation of the HUD projector (4). The electrically conductive coating (20) has precisely one electrically conductive layer (21) which is based on silver and below which a lower dielectric layer (22a) or layer sequence (22a, 22b, 22c) with a refractive index of at least 1.9 is arranged and above which an upper dielectric layer (23a) or layer sequence (23a, 23b, 23c) with a refractive index of at least 1.9 is arranged. The ratio of the optical density of the upper dielectric layer (23a) or layer sequence (23a, 23b, 23c) to the optical density of the lower dielectric layer (22a) or layer sequence (22a, 22b, 22c) equals at least 1.7. A respective busbar (7.1, 7.2) which is provided for connecting to a voltage source is arranged on both sides of the sensor region (S) and is connected to the electrically conductive coating (20) such that a current path for a heating current is formed between the busbars (7.1, 7.2), said current path running across the sensor region (S).