Ceramic Pressure Sensor with Integrated Circuit

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Solution Overview

Problem

Existing pressure sensors face challenges in reducing overall dimensions, manufacturing costs, production reliability, and operating accuracy, particularly due to the use of separate fiberglass printed circuit boards and complex mounting techniques.

Innovation Solution

A pressure sensor design that utilizes a ceramic body as both the substrate and support for the circuit, eliminating the need for a separate fiberglass board, with a die bonded directly onto the ceramic body and connected via flexible micro-wires, allowing for a more compact and reliable structure with integrated temperature detection capabilities.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a separate fiberglass printed circuit board is used to support the circuit arrangement, then the circuit components can be mounted and connected, but the overall dimensions of the sensor increase and manufacturing complexity increases

Engineering Contradiction:
Improvecircuit mountingVSAvoidsensor dimensions
Core Design Contradiction:
Ease of manufactureVSVolume of moving object

Solution Approach 1:

The patent merges the circuit support function with the sensor body by directly forming the circuit arrangement on the ceramic body surface. The ceramic body serves dual purposes: as the structural housing and as the substrate for the circuit pattern, eliminating the need for a separate fiberglass printed circuit board. This integration reduces the overall sensor dimensions while maintaining circuit functionality.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The ceramic body is designed to perform multiple functions simultaneously: it provides mechanical housing, electrical insulation, and circuit support. The circuit pattern is formed directly on the ceramic body surface, making the body a multi-functional component that eliminates the need for additional support structures.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Ease of manufacture

If a separate fiberglass printed circuit board is used, then circuit components can be mounted, but manufacturing costs and device complexity increase

Engineering Contradiction:
Improvecircuit assemblyVSAvoidmounting structure
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The circuit pattern is formed directly on the ceramic body surface through screen printing or similar techniques, eliminating the need for a separate fiberglass board and reducing the number of assembly steps. The ceramic body itself becomes the circuit carrier, simplifying both manufacturing and the overall device structure.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The ceramic body provides its own surface for circuit formation, eliminating the need for external support structures. The body serves its own circuit mounting needs through direct pattern formation on its surface, reducing dependency on additional components.

Inventive Principle:
Principle #25Self-service

3Reliability

If rigid wire bonding is used to connect the die to the circuit board, then electrical connections can be established, but the sensor is sensitive to mechanical stress and detection errors increase

Engineering Contradiction:
Improveelectrical connectionVSAvoidpressure detection accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent uses flexible micro-wires with diameters of 5-100 microns to connect the die to the circuit pattern. These flexible connections can accommodate mechanical stress and diaphragm deformation without breaking or causing measurement errors, unlike rigid wire bonds. The flexibility allows the connection to move with the diaphragm during pressure measurement.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The wire diameter is reduced to the micrometer range (5-100 microns), which changes the mechanical properties from rigid to flexible. This parameter change allows the connection to accommodate stress and deformation while maintaining electrical connectivity, improving measurement precision.

Inventive Principle:
Principle #35Parameter changes

4Ease of manufacture

If the die is mounted on a separate circuit board, then the integrated circuit can be connected, but the overall sensor size increases

Engineering Contradiction:
Improvedie mountingVSAvoidsensor compactness
Core Design Contradiction:
Ease of manufactureVSVolume of moving object

Solution Approach 1:

The die is mounted directly on the ceramic body surface without requiring a separate circuit board. The ceramic body serves as the mounting substrate, integrating the die attachment function into the existing structure and minimizing the overall sensor volume.

Inventive Principle:
Principle #5Merging (Combining)

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 design reduces the sensor's size and manufacturing costs while enhancing production reliability and accuracy, with improved temperature detection and reduced detection errors, achieving better performance and efficiency in pressure measurement.

Implementation Method 1

the die (15) is provided with temperature detector means, configured to detect the temperature of the sensor (1)

Methodology Applied
Scientific EffectTemperature detection: Thermocouple

Implementation Method 2

a pressure sensor, which detects the pressure of a fluid acting on a surface of an elastic diaphragm from a change in the electrostatic capacitance between opposed electrodes provided on opposed surface of a ceramic base and the elastic diaphragm

Methodology Applied
Scientific EffectElectrostatic capacitance: Capacitance

Implementation Method 3

a detector element, adapted to detect a bending or deformation of the same diaphragm; for example made up of a resistive bridge

Methodology Applied
Scientific EffectResistive detection: Electrical Resistance

Data Source

PatentEP2433107B1Pressure sensor
Publication Date: 2024.02.21 METALLUX SA
  • EP2433107B1 patent drawingFigure 1~2
  • EP2433107B1 patent drawingFigure 3~4
  • EP2433107B1 patent drawingFigure 5~6

AI summary

A pressure sensor (1 ) has a sensor body (2, 20) at least partly formed with an electrically insulating material, particularly a ceramic material, defining a cavity (3) facing on which is a diaphragm (20) provided with an electric detector element, configured for detecting a bending of the diaphragm (20). The sensor body (2, 20) supports a circuit arrangement (6), comprising a plurality of circuit components (7, 15), among which an integrated circuit (15), for treating a signal generated by the detection element. The circuit arrangement (6) includes tracks made of electrically conductive material directly deposited on a surface of the sensor body (2, 20) made of electrically insulating material, the integrated circuit is made up of a die made of semiconductor material (15) directly bonded onto the surface of the sensor body and the die (15) is connected to respective tracks (9) by means of wire bonding, i.e. by means of thin connecting wires (16) made of electrically conductive material.