Vacuum Insulated Panel Seal Structure for Low Thermal Stress
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Solution Overview
Problem
Conventional vacuum insulated glass perimeter sealing systems face issues such as significant de-tempering of glass, lack of durability, hermiticity problems, slow processing times, and high manufacturing costs due to thermal heating methods.
Innovation Solution
A vacuum insulating panel with a multi-layer edge seal structure, comprising a main seal layer and primer layers, where the second seal layer includes boron oxide and bismuth oxide, and the main seal layer is narrower and thinner to reduce induced transient thermal stress, combined with localized laser firing for efficient processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermal heating methods are used for seal firing, then the seal can be formed hermetically, but significant de-tempering of glass occurs and processing time increases
Solution Approach 1:
The patent replaces conventional thermal heating methods with laser irradiation to fire the seal material. The laser provides localized, rapid heating that cures the seal without subjecting the entire glass assembly to prolonged high temperatures, thereby reducing processing time while maintaining seal hermeticity.
Solution Approach 2:
The laser firing process uses periodic or pulsed irradiation to heat the seal material to curing temperature briefly, then allows rapid cooling. This periodic heating-cooling cycle achieves seal formation without sustained high-temperature exposure that would cause de-tempering or extend processing time.
2Ease of manufacture
If conventional seal structures are used, then the seal can be formed, but induced transient thermal stress reduces durability
Solution Approach 1:
The patent applies local quality by using a narrower main seal layer in the region most susceptible to thermal stress, while maintaining adequate seal thickness in less critical areas. This localized variation in seal geometry reduces induced transient thermal stress during laser firing while preserving seal formation capability and overall durability.
Solution Approach 2:
The seal structure uses a composite composition including boron oxide and bismuth oxide in specific ratios, creating a material with optimized thermal and mechanical properties. This composite formulation reduces thermal stress during processing while maintaining hermeticity and durability.
3Reliability
If wider and thicker main seal layers are used, then seal hermeticity improves, but induced transient thermal stress increases
Solution Approach 1:
The patent optimizes the parameters of the seal material composition, specifically the ratios of boron oxide (20-65 mol%) and bismuth oxide (1-20 mol%), to achieve a material that cures effectively with minimal thermal stress. This parameter optimization allows adequate seal hermeticity with reduced thickness compared to conventional seals.
Solution Approach 2:
The main seal layer is designed with non-uniform thickness, being narrower in regions where laser irradiation is applied, to reduce transient thermal stress during processing. The localized thickness variation maintains hermeticity at the seal interface while minimizing stress accumulation during curing.
4Manufacturing precision
If slow processing is used, then seal quality improves, but manufacturing cost increases
Solution Approach 1:
The patent replaces slow, conventional thermal heating with rapid laser irradiation for seal curing. The laser provides concentrated energy that fires the seal material quickly and uniformly, achieving high seal quality while dramatically reducing processing time and increasing manufacturing productivity.
Solution Approach 2:
The seal material is formulated and positioned in advance to require minimal processing energy and time. The boron oxide-bismuth oxide composition is designed to cure rapidly under laser irradiation, and the seal layer geometry is pre-optimized to ensure uniform curing without requiring slow, gradual heating, thus improving both quality and efficiency.
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 maintains vacuum hermeticity, retains compressive stress in tempered glass, reduces thermal stress gradients, improves durability and hermiticity, and enhances manufacturing efficiency, leading to cost-effective production of vacuum insulating panels.
Implementation Method 1
localized laser firing for efficient processing
Implementation Method 2
Providing a vacuum in the space between the substrates reduces conduction and convection heat transport
Implementation Method 3
Providing a vacuum in the space between the substrates reduces conduction and convection heat transport
Implementation Method 4
reducing radiative energy with a low-emissivity (low-E) coating provided on one of the substrates
Data Source
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AI summary
A vacuum insulating panel includes first and second substrates (e.g., glass substrates), a hermetic edge seal, a pump-out port, and spacers sandwiched between at least the two substrates. The gap between the substrates may be at a pressure less than atmospheric pressure to provide insulating properties. The vacuum insulating panel may include a multi-layer edge seal structure, including at least one layer including boron oxide (e.g., B2O3 or any other stoichiometry).