Multilayer Solar Control Glazing for Low Solar Factor Stability
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Solution Overview
Problem
Existing solar control glazings struggle to achieve high selectivity, stable aesthetic appearance, and angular stability while maintaining low solar factor and light transmission, often resulting in undesirable purple tints and variations due to manufacturing fluctuations.
Innovation Solution
A multilayer solar control stack with at least three functional layers and transparent dielectric coatings, incorporating a metallic-absorbing layer within the stack, with specific optical thickness ratios and a sacrificial layer to withstand high-temperature treatments, ensuring consistent optical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a solar control stack with functional layers is used to reduce solar energy transmission, then the solar factor decreases, but light transmission also decreases
Solution Approach 1:
The patent applies local quality by introducing a metallic-absorbing layer with specific optical absorption properties at particular positions within the stack. This layer selectively absorbs solar radiation in the visible spectrum while maintaining infrared reflection capabilities of functional layers, thereby reducing solar factor without proportionally reducing light transmission. The metallic-absorbing layer's specific optical characteristics enable differential treatment of different wavelength ranges, resolving the contradiction between solar factor reduction and light transmission maintenance.
2Strength
If heat treatment operations are performed on coated substrate to strengthen glass, then mechanical strength improves, but functional layers deteriorate and lose optical properties
Solution Approach 1:
The patent applies preliminary action by depositing a sacrificial layer before the functional layers during the coating process. This sacrificial layer is specifically designed to oxidize during subsequent heat treatment operations, forming a protective barrier that prevents oxygen from reaching and degrading the functional layers. By performing this protective action in advance, the patent enables heat treatment to strengthen the glass without compromising the optical properties of the functional layers, thereby resolving the contradiction between mechanical strength improvement and optical property preservation.
3Productivity
If manufacturing processes are simplified to reduce costs, then productivity improves, but manufacturing precision decreases
Solution Approach 1:
The patent applies parameter changes by defining specific optical thickness ratios for dielectric coatings (e.g., ratio between third and fourth dielectric coatings between 1.25 and 3.0) and specific thickness ranges for the metallic-absorbing layer (1-7 nm). These parameter specifications create a robust design where variations within acceptable ranges maintain consistent optical properties. This approach enables manufacturers to achieve high precision optical performance without requiring extremely tight process control, thereby resolving the contradiction between manufacturing efficiency and optical property consistency.
Data Source
AI summary
The present invention relates to a substrate carrying a multilayer solar control stack, as well as to a multiple glazing incorporating at least one such sheet of glassy material carrying a solar control stack. The multilayer solar control stack comprises at least n functional layers based on a material which reflects infrared radiation and (n+1) transparent dielectric coatings such that each functional layer is surrounded by transparent dielectric coatings, n being greater than or equal to 3. The stack comprises at least one layer of metallic nature absorbing in the radiation which is visible inside the stack. The invention applies particularly to the formation of solar control glazings with low solar factor.