Flat Ceramic Pressure Sensor Sintering Method
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Solution Overview
Problem
Dome-shaped piezoresistive ceramic pressure sensors are not suitable for producing absolute or differential sensors and have limited overpressure resistance due to their construction, which can lead to membrane breakage, especially when measuring fluids that can freeze.
Innovation Solution
A method for producing flat ceramic pressure sensors using semi-finished sheet-like workpieces of alumina, where the membrane and support are coupled using sinterable glass, eliminating the need for specific molds and reducing the thickness of the support to increase breaking pressure, and allowing for the production of both absolute and relative sensors with improved overpressure resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If dome-shaped sensors are used, then ease of manufacture is improved, but overpressure resistance deteriorates
Solution Approach 1:
The patent inverts the conventional dome-shaped sensor design by using a flat membrane configuration. This inversion allows the membrane to be supported from both sides, enabling it to withstand overpressure without the structural limitations of dome-shaped sensors. The flat membrane with dual-sided support achieves both manufacturability and enhanced overpressure resistance.
Solution Approach 2:
The patent changes the geometric parameter of the membrane from dome-shaped to flat, and modifies the support structure to provide bilateral support. This parameter change enables the membrane to distribute stress more evenly during overpressure events, increasing the breaking pressure while maintaining ease of manufacture through standard ceramic processing techniques.
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 enables the production of flat ceramic pressure sensors with enhanced overpressure resistance and measurement repeatability, capable of withstanding atmospheric pressure, while maintaining compact dimensions and ease of machining, and reduces the risk of breakage from fluid freezing by minimizing the volume of the measuring chamber.
Implementation Method 1
the electrical coupling between the membrane and the support is performed by deposition and sintering of at least one layer of an electrically conductive sinterable electrical connection material, the mechanical coupling between the membrane and the support is performed by deposition and sintering of at least one layer of sinterable mechanical connection material
Implementation Method 2
The resistors, made of piezoresistive material, are positioned in such a way that, while the membrane flexes, two resistors (belonging to opposite sides of the bridge) lengthen, determining an increase in resistance, and simultaneously the other two are compressed, determining a decrease in resistance
Implementation Method 3
The membrane flexes under the effect of pressure and this flexion can be measured by means of a resistive bridge
Data Source
Figure 1~2
Figure 3a~3d
Figure 4a~4e
AI summary
A method for production of a pressure sensor (130) comprising a flat flexible membrane (100) made of a ceramic material and a flat rigid support (110) thereof made of a ceramic material, comprising the following steps: - realising an electric circuit (16, 18) on the membrane (100); - realising an electric contact with the outside on the support (110); - depositing an electrically conductive material on the support (110); - realising an electrical and mechanical coupling between the membrane (100) and the support (110); the electrical coupling between the membrane (100) and the support (110) being performed by deposition and sintering of at least one layer of an electrically conductive sinterable electrical connection material; the mechanical coupling between the membrane (100) and the support (110) being performed by deposition and sintering of at least one layer of sinterable mechanical connection material that is electrically insulating and/or isolated from the layer of sinterable electrical connection material; the layer of sinterable electrical connection material and the layer of sinterable mechanical connection material undergoing re flow together in a single step in a sintering furnace.