Laser-Welded Glass Pressure Sensor Mounting for Thermal Accuracy
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Solution Overview
Problem
Existing pressure sensor arrangements face limitations in accuracy and functionality due to mechanical stresses caused by thermal expansion discrepancies between different materials when exposed to high or low temperatures, especially in aggressive media.
Innovation Solution
A pressure sensor arrangement featuring a sensor element with a membrane, connected to a glass substrate via laser welding with ultrashort laser pulses, eliminating the need for additional joining materials and minimizing thermal expansion discrepancies, thus reducing mechanical stresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If inorganic joining materials (solder, joining glasses) are used to mechanically mount the sensor element on metal or ceramic substrates, then the sensor arrangement can be mechanically stable, but the significant difference in coefficients of thermal expansion (up to 10 ppm/K or more) between sensor element, solder material and substrate causes mechanical stresses leading to pressure measurement errors
Solution Approach 1:
The patent applies homogeneity by using a glass substrate with a coefficient of thermal expansion matched to that of the sensor element (difference less than 1 ppm/K). This material homogeneity eliminates the thermal expansion mismatch problem inherent in heterogeneous material combinations, preventing mechanical stresses and maintaining pressure measurement accuracy across temperature ranges.
Solution Approach 2:
The patent extracts and eliminates the problematic intermediate joining materials (solder, joining glasses) from the assembly. By directly bonding the sensor element to the glass substrate without these intermediary materials, the invention removes the source of thermal expansion discrepancies and associated mechanical stresses.
2Ease of manufacture
If organic adhesives are used for mechanical mounting of the sensor element, then the mounting process is simplified, but organic adhesives cannot withstand aggressive liquids and fail under aggressive conditions
Solution Approach 1:
The patent replaces durable but complex inorganic joining materials with a simpler glass bonding approach. While glass bonding requires precision, it eliminates the need for separate adhesive materials and their associated curing processes, simplifying the overall manufacturing while achieving both mechanical stability and chemical resistance.
3Measurement precision
If laser welding with ultrashort laser pulses is used to connect the sensor element to the glass substrate, then additional joining materials are eliminated and thermal expansion discrepancies are minimized, but the manufacturing process becomes more complex
Solution Approach 1:
The patent replaces mechanical joining methods (soldering, adhesive bonding) with laser welding technology. This substitution enables direct bonding of the sensor element to the glass substrate without intermediate materials, eliminating thermal expansion mismatches. The ultrashort laser pulses provide precise localized heating that achieves strong bonds while minimizing thermal affect on surrounding materials.
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 provides a durable, reliable, and accurate pressure sensor arrangement capable of operating in a wide temperature range (−40°C to 150°C) and withstanding aggressive media, reducing pressure measurement errors and enhancing the functionality of complex technical systems.
Implementation Method 1
The substrate material is completely transparent to the laser wavelength. The light is focused through the substrate without heat input into it up to a joining area between the substrate and the sensor element
Implementation Method 2
At the joining area, the heat leads via non-linear absorption (multiphoton absorption) in the focal area over a few tens of micrometers extremely locally via fusion to a mechanically stable joining
Implementation Method 3
At the joining area, the heat leads via non-linear absorption (multiphoton absorption) in the focal area over a few tens of micrometers extremely locally via fusion to a mechanically stable joining of sensor element and substrate
Implementation Method 4
the heat leads via non-linear absorption (multiphoton absorption) in the focal area
Implementation Method 5
The detection element is formed on the membrane... The detection element is designed to measure a pressure of the medium
Data Source
AI summary
In an embodiment a pressure sensor arrangement includes a sensor element having a top side and a bottom side, wherein the sensor element comprises a membrane configured to be exposed to a medium and at least one detection element configured to measure a pressure of the medium, a substrate serving as a carrier of the sensor element, wherein the substrate comprises glass and a connection interface, produced by laser welding, arranged between the sensor element and the substrate, wherein the sensor element and the substrate are mechanically firmly and hermetically connected to one another at the connection interface.