Patterned Black Ceramic Layer for Bent Glazing Emissivity
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Solution Overview
Problem
The challenge lies in producing bent and/or tempered glazing with thermal radiation reflective coatings, particularly low-E coatings, which face difficulties due to the physical properties of low-E coatings affecting the bending process and the introduction of black ceramic layers, leading to non-uniform heating and unacceptable curvature shapes.
Innovation Solution
A method involving a glass sheet with a thermal radiation reflective coating on its interior-side surface and a black ceramic layer applied partially or along the perimeter, featuring a pattern to mitigate emissivity contrast and achieve a smooth temperature profile during bending and tempering, ensuring a progressive shape suitable for vehicle design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a low-E coating is applied to the glass sheet to improve thermal radiation reflection, then thermal comfort is improved, but the bending process becomes difficult due to non-uniform heating
Solution Approach 1:
The patent applies a patterned black ceramic layer selectively in specific zones (such as perimeter regions or localized areas) rather than uniformly across the entire glass surface. This creates local variations in emissivity that compensate for the low-E coating's low emissivity in specific areas, enabling more uniform heating during bending while preserving thermal reflection properties in other areas.
2Shape
If a black ceramic layer is added to the glass sheet to improve aesthetic appearance and UV protection, then visual quality is improved, but non-uniform heating occurs during bending due to contrasting emissivity
Solution Approach 1:
The black ceramic layer is applied in a specific pattern (such as perimeter zones, segmented regions, or controlled distributions) rather than uniformly across the entire surface. This localized application creates strategic emissivity variations that promote uniform heat distribution during bending while maintaining aesthetic appearance and UV protection functions.
Solution Approach 2:
The patent modifies the emissivity parameter of the glass sheet by adding the black ceramic layer in specific patterns. This changes the thermal radiation characteristics locally, creating zones with different emissivity values that compensate for each other during heating, thereby achieving more uniform temperature distribution across the entire glass surface.
3Strength
If the black ceramic layer covers the low-E coating to improve adhesion and aesthetics, then bonding strength is improved, but thermal radiation reflection properties deteriorate
Solution Approach 1:
The black ceramic layer is applied selectively in specific zones (such as perimeter regions or localized areas) rather than covering the entire low-E coated surface. This preserves the thermal radiation reflection properties in areas where the low-E coating remains exposed while providing adhesion and aesthetic benefits in areas where the black ceramic is applied.
Solution Approach 2:
The glass sheet surface is segmented into different functional zones: areas with black ceramic layer for adhesion and aesthetics, and areas with exposed low-E coating for thermal radiation reflection. This segmentation allows both functionalities to coexist without mutual interference.
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
This approach reduces the 'U-shape' or 'reverse curvature' issues, allowing for smooth glass shaping and improved thermal comfort by maintaining a consistent temperature profile, thus addressing the aesthetic and functional requirements of car manufacturers.
Implementation Method 1
low-E coatings, which reflect thermal radiation
Implementation Method 2
thanks to its long-waves infrared (IR) energy reflection properties
Implementation Method 3
The black layer has a high heating absorbance
Implementation Method 4
Hot bending and/or tempering the glass sheet
Implementation Method 5
to produce a bent and/or tempered glazing
Data Source
AI summary
The present invention concerns a method to produce a bent and/or tempered glazing offering improved thermal comfort, comprising the following steps (a) Providing a glass sheet having an outer-side surface and an interior-side surface, (b) Applying a thermal radiation reflective coating over at least a layer of the surface of the interior-side surface of the glass sheet, (c) Applying a black ceramic layer on at least a portion of at least the interior-side surface of the glass sheet, the black ceramic layer covering at least partially the thermal radiation reflective coating and/or running alongside the area covered by the thermal radiation reflective coating, (d) Hot bending and/or tempering the glass sheet. According to the present invention, the black ceramic layer has a pattern that mitigates the contrast in emissivity during the step d. between the area where the thermal radiation reflective coating is not covered by the black layer and the area where the black ceramic layer covers at least partially the thermal radiation reflective coating and/or the black ceramic layer runs alongside the area covered by the thermal radiation reflective coating.