MEMS Pressure Sensor Response Time Test Chamber
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Solution Overview
Problem
There is a need for an effective method to measure the response time of microelectromechanical systems (MEMS) pressure sensors, particularly those designed to capture rapid changes in pressure, as in side airbag automotive applications, where sensors must detect and output pressure signals within stringent time frames.
Innovation Solution
A system comprising a pressure controller, air tanks, a switch mechanism, and a test chamber is used to generate a rapid pressure stimulus pulse, allowing for the measurement of the response time of MEMS pressure sensors by recording the output signals from both the device under test and a control pressure sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional testing methods are used for pressure sensors, then general functionality can be verified, but response time measurement for rapid pressure changes cannot be accurately measured
Solution Approach 1:
The system pre-pressurizes tanks to different pressure levels before testing. The switch mechanism is pre-positioned to rapidly connect the appropriate pressurized tank to the test chamber, enabling immediate pressure stimulus application without delay, which is critical for measuring fast response times.
Solution Approach 2:
The system applies pressure stimuli in periodic pulse form by rapidly switching between pressurized tanks. This periodic pressure application allows for repeated measurements and statistical analysis of response time, improving measurement precision while maintaining adaptability to rapid pressure change scenarios.
2Productivity
If a simple test chamber design is used, then device complexity is reduced, but the ability to generate rapid pressure stimuli for response time measurement is compromised
Solution Approach 1:
The test system is segmented into independent functional modules: multiple pressurized tanks, a switch mechanism, a test chamber, and control electronics. This segmentation allows each component to be optimized independently for its specific function, enabling rapid pressure stimulus generation while keeping the overall system manageable through modular architecture.
Solution Approach 2:
The switch mechanism acts as an intermediary between the pressurized tanks and the test chamber. It rapidly connects the appropriate pre-pressurized tank to the chamber, enabling fast pressure stimulus application without requiring a complex direct coupling system, thus balancing productivity and complexity.
3Speed
If pressure sensors are designed for high speed pressure capture, then response time is reduced, but verification of response time parameters becomes more difficult
Solution Approach 1:
The system incorporates feedback through precise timing measurement of the pressure stimulus application and the sensor response. By measuring the time interval between stimulus application and sensor output with high precision, the system can verify response time parameters even for sensors with very fast response characteristics.
Solution Approach 2:
The system replaces manual or slow mechanical testing methods with an automated electronic control and measurement system. The rapid electronic switching and digital timing measurement enable accurate verification of fast response time parameters that would be impossible to measure with conventional mechanical testing approaches.
Data Source
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AI summary
A test chamber is used within a system for testing microelectromechanical systems (MEMS) pressure sensors. The system includes a processor, two air tanks pressurized to different air pressures, a high speed switch mechanism, and the test chamber. The test chamber houses a MEMS pressure sensor to be tested, a control pressure sensor, and a temperature sensor. The MEMS pressure sensor and the control pressure sensor are located in a cavity within the test chamber. The cavity is of minimal size and has a domed inner surface. A response time of the MEMS pressure sensor within the cavity can be characterized by utilizing the system and subjecting the MEMS pressure sensor to a pressure stimulus pulse produced by switching between the two air tanks.