Glass Ceramic Ceramming Setter Plates and Parting Agent Coatings
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Solution Overview
Problem
Conventional ceram processes using ceramic and refractory materials fail to produce glass ceramic sheets with high optical quality due to heat transfer and heat capacity limitations, leading to warping issues caused by sticking, thickness variations, and applied loads during the manufacturing process.
Innovation Solution
A method involving a glass stack configuration with setter plates made from reaction bonded silicon carbide, a parting agent layer formed from an aqueous dispersion of boron nitride and a colloidal inorganic binding agent, and controlled thermal treatment to minimize stress and warp, while maintaining optical quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional ceramic and refractory materials are used as setters in ceram processes, then the manufacturing process can be performed, but the heat transfer and heat capacity limitations cause warping and skin effects that deteriorate optical quality
Solution Approach 1:
The patent changes the material parameter of the setter from conventional ceramic/refractory materials to a metal alloy composition with specific thermal properties (thermal conductivity 10-50 W/m·K, thermal expansion coefficient 5-15 ×10^-6/K). This parameter change enables improved heat transfer and heat capacity, eliminating warping and skin effects while maintaining manufacturing feasibility.
2Productivity
If glass sheets are stacked during manufacturing, then productivity increases, but sticking between sheets and to the setter causes warping
Solution Approach 1:
The patent introduces a parting agent layer as an intermediary substance between glass sheets and between the glass sheets and the metal alloy setter. This parting agent prevents sticking during the ceram process, allowing sheets to be stacked for improved productivity while eliminating warping caused by adhesion forces.
3Shape
If thick parting agent layers are applied to prevent sticking, then warping is reduced, but optical transmission quality deteriorates
Solution Approach 1:
The patent optimizes the thickness parameter of the parting agent layer to a specific range (1-10 micrometers). This parameter change ensures sufficient separation to prevent sticking and warping while maintaining adequate optical transmission for display applications. The metal alloy setter's thermal properties also contribute to reduced warping, allowing thinner parting agent layers.
4Manufacturing precision
If conventional setters are used, then the process is simple, but the heat capacity limitations cause skin effects that reduce optical quality
Solution Approach 1:
The patent changes the heat capacity parameter of the setter material by using a metal alloy composition with specific thermal properties (thermal conductivity 10-50 W/m·K). This enables the setter to absorb and distribute heat more effectively during the ceram process, preventing skin effects and improving optical quality while maintaining process simplicity.
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 approach results in glass ceramic articles with improved optical quality and reduced warping, suitable for applications requiring high transparency and mechanical strength, such as portable electronic devices.
Implementation Method 1
a parting agent layer formed from an aqueous dispersion including boron nitride and a colloidal inorganic binding agent
Implementation Method 2
setter plates made from reaction bonded silicon carbide
Implementation Method 3
exposing the glass stack configuration to a ceramming cycle sufficient to ceram the plurality of glass sheets
Data Source
AI summary
Glass stack configurations including a carrier plate, setter plates, and glass sheets for thermal treatment of the glass sheets to form glass ceramic articles are provided. The glass stacking configurations and components described herein are selected to improve thermal uniformity throughout a glass stack during ceramming processes while maintaining or even reducing the stresses in the resultant glass ceramic article. Accordingly, the glass ceramic articles made according to the various embodiments described herein exhibit improved optical qualities and less warp than glass ceramic articles made according to conventional processes. Various embodiments of carrier plates, setter plates, parting agent compositions, and methods of stacking glass sheets are described.