Vehicle Windshield Terminal Soldering With Low-Porosity Light Shielding
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Solution Overview
Problem
The use of lead-free solder in joining conductors to terminals on vehicle windshields results in residual stress and potential cracking due to the higher melting point and thermal expansion differences with glass, leading to a decrease in the breaking strength of the glass plate.
Innovation Solution
A windshield manufacturing method involving a laminated glass structure with a conductor and terminal jointed using lead-free solder, where the porosity of the light-shielding layer is limited to 12% or lower to enhance the breaking strength by reducing voids and improving the denseness of the layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If lead-free solder is used to join conductor to terminal, then environmental compliance and soldering reliability are improved, but residual stress and cracking risk increase due to thermal expansion differences
Solution Approach 1:
The patent applies local quality by creating a light-shielding layer with specific porosity characteristics (10-50% porosity) in the region where the conductor is formed. This localized structural modification allows the glass plate to accommodate thermal stress from lead-free soldering in the conductor region while maintaining overall structural integrity and breaking strength.
2Object-affected harmful factors
If light-shielding layer porosity is increased, then light-shielding performance is improved, but breaking strength and crack resistance decrease
Solution Approach 1:
The patent applies parameter changes by optimizing the porosity of the light-shielding layer to a specific range (10-50%). This controlled parameter modification achieves sufficient light-shielding performance while preventing excessive porosity that would compromise breaking strength and increase crack susceptibility, particularly in the conductor formation region.
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 method effectively increases the breaking strength of the glass plate both before and after terminal attachment by minimizing porosity in the light-shielding layer, thereby reducing the risk of cracking and enhancing the structural integrity of the windshield.
Implementation Method 1
a light-shielding layer is formed in the peripheral region of the glass plate
Implementation Method 2
the terminal is joined to the terminal joint portion of the conductor through lead-free solder... due to the higher melting point and thermal expansion differences with glass, leading to residual stress
Data Source
AI summary
A windshield for vehicle includes a laminated glass in which a first glass plate and a second glass plate are bonded together with an intermediate film interposed therebetween, in which the laminated glass includes a glass plate with a terminal including the second glass plate, a conductor, and the terminal, the conductor including a terminal joint portion, and the terminal being joined to the terminal joint portion of the conductor through lead-free solder; the conductor includes a feeding portion for feeding electricity to an electric function portion, and the feeding portion includes the terminal joint portion; the glass plate with the terminal includes a light-shielding layer between the second glass plate and at least a part of the conductor including the feeding portion; and a porosity of at least a forming region of the feeding portion in the light-shielding layer is 12% or lower.