HUD Laminated Glazing Coating for Solar Control and Heating
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Solution Overview
Problem
Existing laminated glazings for head-up displays face challenges in combining solar control properties with heating functions while maintaining low solar factor, high light transmission, color neutrality, and high reflection of p-polarized electromagnetic radiation in the visible spectrum, and low surface electrical resistance.
Innovation Solution
A laminated glazing comprising a first glass sheet, a second glass sheet, a lamination interlayer, and a functional coating with a dielectric module and a metallic functional layer, where the dielectric module includes a tungsten oxide layer, either pure sub-stoichiometric or doped with elements from Group 1, to achieve the desired optical and electrical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a functional coating with metallic layers is used to achieve high reflection of p-polarized electromagnetic radiation, then the head-up display performance is improved, but the surface electrical resistance increases, reducing heating efficiency
Solution Approach 1:
The patent uses a composite functional coating combining multiple metallic layers (silver, aluminum, nickel-chromium) with dielectric layers (tungsten oxide, silicon nitride, zinc oxide). This composite structure optimizes both optical reflection properties for HUD and electrical conductivity for heating, resolving the contradiction between high reflection and low electrical resistance.
2Loss of energy
If the glazing includes solar control properties to reduce infrared radiation, then the solar factor is reduced, but the heating function effectiveness is compromised
Solution Approach 1:
The functional coating is designed with different layers having distinct local properties: outer dielectric layers (tungsten oxide, silicon nitride) provide solar control and infrared rejection, while the inner metallic functional layer (silver or aluminum) provides both high reflectivity for HUD and low electrical resistance for heating. This local differentiation resolves the contradiction between solar control and heating effectiveness.
3Object-generated harmful factors
If a lamination interlayer of varying thickness is inserted to reduce ghosting, then the ghost image is reduced, but the manufacturing complexity and cost increase
Solution Approach 1:
The patent extracts the ghosting reduction function from the lamination interlayer by placing the functional coating directly on the inner glass sheet. This eliminates the need for complex wedge-shaped lamination while still achieving ghost image reduction through the optical properties of the functional coating layers, particularly the dielectric modules with specific refractive indices.
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 glazing achieves a selectivity of over 1.3 with high light transmission, color neutrality, and low surface electrical resistance, suitable for effective heating applications.
Implementation Method 1
a first dielectric module, a metallic functional layer and a second dielectric module, said metallic functional layer being located between the first dielectric module and the second dielectric module; said glazing being characterized in that: the first dielectric module and/or the second dielectric module comprises (or comprise) a tungsten oxide layer
Implementation Method 2
These systems or devices include a projector, usually located close to the vehicle dashboard, configured to project an image onto an area of the vehicle windshield. The projected image appears to the vehicle driver as a virtual image behind the windshield
Implementation Method 3
Most HUD devices are based on the emission of polarized electromagnetic radiation with s-type polarization and an angle of incidence of around 65° to the normal to the windshield. This angle is close to the Brewster angle for a glass-air interface, which is around 56.5° for soda-lime glass
Implementation Method 4
the main surfaces of the windshield are usually arranged at different angles by inserting a lamination interlayer of varying thickness, so that the ghost image and the main image are superimposed
Implementation Method 5
it is common practice to use HUD devices whose implementation is based on the emission of electromagnetic radiation polarized according to a p-type polarization and onto a windshield comprising a functional coating adapted to the formation of a new reflective interface within said windshield for this type of radiation
Data Source
AI summary
A laminated glazing includes a first glass sheet, a second glass sheet, a lamination interlayer in adhesive contact with the outer first glass sheet and the inner second glass sheet; a functional coating of thin layers arranged on the second glass sheet and including, starting from the second glass sheet, a first dielectric module, a metallic functional layer and a second dielectric module, the metallic functional layer being located between the first dielectric module and the second dielectric module. The first dielectric module and/or the second dielectric module include a tungsten oxide layer which is made of pure sub-stoichiometric tungsten oxide, WOx, with x between 2.55 and 2.98, or which is made of doped tungsten oxide including at least one doping element selected from the chemical elements of group 1 according to the IUPAC nomenclature.