HUD Composite Pane P-Polarized Reflection Coating
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Solution Overview
Problem
Current head-up display (HUD) projection arrangements face challenges in achieving high transmittance in the visible spectral range, high reflectance for infrared components of solar radiation, and consistent reflectance for p-polarized radiation, while also avoiding ghost images and maintaining color neutrality, which is costly and complex to implement with existing wedge films and multi-layer coatings.
Innovation Solution
A composite pane with a reflection coating comprising alternating electrically conductive silver layers and transparent conductive oxide (TCO) layer modules, which replaces dielectric layers, providing high and consistent reflectivity for p-polarized radiation while reducing infrared radiation input into the vehicle interior, thus enabling a cost-effective and efficient HUD projection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a single metallic layer coating is used for p-polarised radiation reflection, then the reflectance for p-polarised radiation is improved, but the infrared reflection capability deteriorates
Solution Approach 1:
The patent applies composite materials by combining multiple metallic layers (silver and aluminium) with dielectric layers to create a multi-layer coating structure. This composite approach enables the coating to simultaneously achieve high reflectance for p-polarised radiation in the visible spectrum and high reflectance for infrared radiation, while maintaining adequate transmittance. The different materials contribute their respective strengths: silver provides high visible reflectance, aluminium enhances infrared reflection, and dielectric layers provide optical matching and additional functional properties.
2Temperature
If a very thick metallic layer is used to improve infrared reflection, then the infrared reflection capability is improved, but the transmittance in the visible spectral range deteriorates
Solution Approach 1:
The patent applies segmentation by dividing the coating into multiple thin layers instead of using a single thick metallic layer. The coating consists of alternating metallic layers (silver and aluminium) and dielectric layers, with each metallic layer being relatively thin. This segmented structure allows each layer to contribute to specific functions: the thin metallic layers provide selective reflection for both visible and infrared radiation, while the dielectric layers provide optical matching and maintain overall transmittance in the visible range.
3Temperature
If multiple metallic layers separated by dielectric layers are used, then the infrared reflection and visible transmittance are improved, but the device complexity increases
Solution Approach 1:
The patent applies parameter changes by systematically varying the thickness, material composition, and arrangement of multiple layers to optimize performance. The coating includes alternating metallic layers (silver and aluminium) and dielectric layers, with each layer's parameters (thickness, refractive index, material) carefully selected to achieve the desired optical properties. This parametric optimization enables the complex multi-layer structure to deliver superior simultaneous infrared reflection and visible transmittance.
4Temperature
If conventional multi-layer coatings are used to achieve high infrared reflection, then the infrared reflection capability is improved, but the manufacturing cost and process complexity increase
Solution Approach 1:
The patent applies composite materials by combining multiple metallic layers (silver and aluminium) with dielectric layers to create a multi-layer coating structure. This composite approach enables the coating to simultaneously achieve high reflectance for p-polarised radiation in the visible spectrum and high reflectance for infrared radiation, while maintaining adequate transmittance. The different materials contribute their respective strengths: silver provides high visible reflectance, aluminium enhances infrared reflection, and dielectric layers provide optical matching and additional functional properties.
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 achieves high-intensity, color-neutral HUD projections with improved infrared reflection and reduced heat input, maintaining high transmittance in the visible spectrum and minimizing ghost images, thus enhancing both safety and economic viability.
Implementation Method 1
a projector (HUD projector) whose radiation, which is at least partially, in particular predominantly, p-polarised, is directed at the HUD region, where the radiation is reflected in the direction of a viewer
Implementation Method 2
high reflectance for infrared components of solar radiation as well as high and the most consistent possible reflectance relative to the p-polarised radiation of the HUD projector
Implementation Method 3
a reflection coating that comprises n electrically conductive layers based on silver and (n+1) layer modules, where n is a natural number greater than or equal to 1
Data Source
AI summary
A projection arrangement for a head-up display (HUD), includes a composite pane including an outer and inner panes joined to one another via a thermoplastic intermediate layer and has an HUD region; and an HUD projector directed at the HUD region. The radiation of the projector is at least partially p-polarised, and the composite pane is provided with a reflection coating suitable for reflecting p-polarised radiation. The reflection coating includes n electrically conductive layers based on silver and (n+1) layer modules, wherein the layer modules and the electrically conductive layers are arranged alternatingly such that each electrically conductive layer is arranged between two layer modules, where n is a natural number greater than or equal to 1. At least one of the layer modules is formed as a layer based on a transparent conductive oxide, and the remaining layer modules, if present, are formed as dielectric layers or layer sequences.