Multilayer Low-E Coating for Heat-Resistant Transparent Substrates
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Solution Overview
Problem
Existing transparent substrates with low-emissivity coatings, such as low-E glass, face challenges in maintaining durability and infrared reflection properties when exposed to repeated high-temperature environments, leading to thermal insulation performance degradation.
Innovation Solution
A multilayer thin film coating comprising a lower dielectric layer, a lower protective layer, a metal functional layer with infrared reflection, an upper protective layer, and an upper dielectric layer, with specific thicknesses and materials to enhance durability and maintain low emissivity, including a planarization layer to improve resistivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the thickness of metal functional layer is increased to improve infrared reflectance and lower emissivity, then thermal insulation effect is enhanced, but durability under repeated high-temperature exposure deteriorates
Solution Approach 1:
The patent uses a composite multilayer structure combining metal functional layer (silver) with dielectric layers (silicon nitride, silicon oxide) and protective layers (nickel-chromium alloy). This composite approach allows the metal layer to provide infrared reflectance while the dielectric and protective layers protect against high-temperature degradation, resolving the contradiction between thermal insulation and durability.
Solution Approach 2:
The coating is segmented into multiple functional layers: lower dielectric layer for adhesion and protection, metal functional layer for infrared reflection, upper dielectric layer for optical performance, and protective layers for durability. This segmentation allows each layer to optimize its specific function while collectively maintaining both thermal insulation and high-temperature durability.
2Loss of energy
If low-emissivity coating is applied to block heat transfer, then thermal insulation is improved, but optical properties and transmittance deteriorate
Solution Approach 1:
The patent applies different material properties to different layers: the metal functional layer provides high infrared reflectance for heat blocking, while the dielectric layers (silicon nitride, silicon oxide) and protective layers are selected for their optical transparency in the visible range. This local quality differentiation allows simultaneous achievement of heat transfer blocking and visible light transmittance.
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 excellent transmittance and emissivity, preventing thermal insulation performance deterioration even under repeated high-temperature exposure, ensuring safety and longevity in heating devices like oven doors.
Implementation Method 1
a metal functional layer having an infrared reflection function
Implementation Method 2
visible rays can be transmitted enough to look into the door or window from the outside
Implementation Method 3
infrared rays can be blocked so that a high temperature inside the heating device is not transmitted to the outside
Data Source
AI summary
Provided is a transparent substrate with a multilayer thin film coating, in which the multilayer thin film coating includes a lower dielectric layer, a lower protective layer, a metal functional layer having an infrared reflection function, an upper protective layer, and an upper dielectric layer, which are sequentially laminated on the transparent substrate, the thickness of the metal function layer is 12 nm or more, and the thickness of the lower protective layer is larger than that of the upper protective layer and the thickness of the lower protective layer is 2 nm or more.