Automotive Window Coating with Dielectric Barrier Layer
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Solution Overview
Problem
Existing motor vehicle window coatings that reflect thermal radiation are either not transparent enough for windshields or front side windows due to significant reduction in visible spectral range transmission, or they are susceptible to corrosion and mechanical damage when exposed to air and environmental influences.
Innovation Solution
A motor vehicle window with a thermal radiation-reflecting coating comprising an adhesive layer, a functional layer with a transparent, electrically conductive oxide, a dielectric barrier layer for regulating oxygen diffusion, and an anti-reflection layer, where the barrier layer has a thickness of 10 nm to 40 nm, ensuring high transmission and corrosion resistance, and can withstand bending and pre-stressing without damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a coating with functional layers made of niobium, tantalum or zirconium is used to reflect thermal radiation, then the heating of the vehicle interior is reduced, but the transmission in the visible spectral range is significantly reduced
Solution Approach 1:
The patent uses a composite coating structure consisting of multiple layers: a base layer made of niobium, tantalum or zirconium for thermal radiation reflection, combined with a transparent conductive oxide layer (such as indium tin oxide) that maintains visible light transmission. This composite structure allows the coating to reflect thermal radiation effectively while remaining transparent in the visible range, resolving the contradiction between energy loss reduction and illumination preservation.
2Loss of energy
If a coating with functional layers made of silver is used to reflect thermal radiation, then the coating is effective, but the coating is susceptible to corrosion and mechanical damage
Solution Approach 1:
The patent replaces the single-layer silver coating with a composite structure where a base layer (niobium, tantalum or zirconium) provides thermal radiation reflection, and a transparent conductive oxide layer provides corrosion and mechanical damage resistance. This composite approach maintains the thermal reflection effectiveness while significantly improving reliability by protecting against environmental degradation.
Solution Approach 2:
The transparent conductive oxide layer acts as an intermediary protective layer between the reactive metal base layer and the external environment. This intermediate layer prevents direct contact between the base layer and corrosive elements while maintaining the thermal radiation reflection function, thus resolving the contradiction between effectiveness and reliability.
3Reliability
If the barrier layer thickness is increased to improve corrosion resistance, then the transmission in the visible spectral range is reduced
Solution Approach 1:
The patent optimizes the barrier layer thickness to a specific range (10 nm to 40 nm) where it provides sufficient corrosion protection while maintaining high visible light transmission. By precisely controlling this critical parameter, the coating achieves both reliability and illumination requirements simultaneously, resolving the contradiction between corrosion resistance and transmission.
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 coating maintains high transmission in the visible spectral range, reduces heat radiation emission into the vehicle interior and external environment, and provides improved thermal comfort while meeting legal transmission requirements and resisting corrosion and mechanical stress.
Implementation Method 1
above the functional layer a dielectric barrier layer for regulating oxygen diffusion
Implementation Method 2
a functional layer which contains at least one transparent, electrically conductive oxide (TCO)... The coating maintains high transmission in the visible spectral range, reduces heat radiation emission
Implementation Method 3
at least an adhesive layer
Data Source
Figure 1~3
Figure 4(a)~4(d)
Figure 5
AI summary
The present invention relates to a sheet comprising at least one substrate (1) and at least one coating (2), which reflects thermal radiation, on at least one surface of the substrate (1), wherein the coating (2) on the substrate (1) contains at least one adhesion layer (3); a functional layer (4), containing at least one transparent, electrically conductive oxide (TCO), above the adhesion layer (3); a dielectric barrier layer (5), for regulating oxygen diffusion, above the functional layer (4); and an anti-reflection layer (6) above the barrier layer (5), wherein the barrier layer (5) has a thickness of 10 nm to 40 nm.