Sensor Device Stress Compensation via Doped Silicon Elements
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Solution Overview
Problem
Existing thermal sensor devices face accuracy issues due to deformation caused by thermal expansion and stress, particularly elongating and shearing stresses, which are not adequately addressed by current two-layered heater structures, and there is a need for a solution to minimize measurement errors from these stress-induced changes.
Innovation Solution
A sensor device with a detecting element on an insulating film over a cavity, utilizing silicon elements doped with different impurities, where the heat generator and temperature sensors are formed using composite materials of polycrystal silicon films to offset resistance changes caused by distortion, effectively reducing the impact of stress on the sensor element.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sensor device is inserted into the bladder to measure urine volume, then measurement precision is improved, but patient comfort deteriorates and infection risk increases
Solution Approach 1:
The sensor device is extracted from the invasive bladder insertion approach and repositioned for external placement on the skin surface. The device measures urine volume non-invasively by detecting changes in electrical impedance through the abdominal wall, eliminating the need for internal insertion while maintaining measurement capability.
Solution Approach 2:
The skin and abdominal wall act as intermediaries between the external sensor device and the bladder. The device measures electrical impedance changes through these intermediate layers to indirectly detect urine volume, avoiding direct contact with the bladder while still obtaining accurate measurements.
2Measurement precision
If a catheter is used for urine output measurement, then measurement precision is improved, but device complexity and infection risk increase
Solution Approach 1:
The measurement function is extracted from the complex catheter system and transferred to an external impedance-based sensor. This eliminates the need for catheter insertion and associated complex components while maintaining accurate urine output measurement through non-invasive electrical impedance detection.
Solution Approach 2:
The mechanical catheter system is replaced with an electrical impedance-based measurement system. Instead of using physical catheters to collect and measure urine, the device uses changes in electrical impedance through the abdominal wall to detect urine volume, simplifying the overall system.
3Reliability
If monitoring is performed during surgery, then reliability is improved, but device complexity increases
Solution Approach 1:
The sensor device automatically detects and monitors urine volume changes through electrical impedance measurements without requiring complex manual intervention or sophisticated processing systems. The measurement process is self-contained, using the body's natural electrical properties to provide continuous monitoring during surgery.
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 highly accurate and reliable physical quantity sensor by offsetting resistance changes due to distortion, improving the sensor's ability to detect air flow with reduced errors from stress-induced deformations.
Implementation Method 1
it has been recognised that air bubbles in the urinary bladder have an insulating effect which can be detected by a sensor device in the form of two pad electrodes
Implementation Method 2
air bubbles in the urinary bladder have an insulating effect which can be detected by a sensor device
Data Source
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AI summary
The purpose of the present invention is to provide a highly accurate and highly reliable physical quantity sensor wherein an error due to stress applied to a sensor element of the physical quantity sensor is reduced. This physical quantity sensor device is provided with: a hollow section formed in a Si substrate; an insulating film covering the hollow section; and a heating section formed in the insulating film. The sensor device is also provided with a detection element that detects the temperature of the insulating film above the hollow section, the detection element is provided with a first silicon element and a second silicon element, and the first silicon element and the second silicon element are doped with different impurities, respectively.