Cantilever Beam Pressure Sensor for Biometric Detection

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Solution Overview

Problem

Existing biological characteristic information detection devices, such as fingertip blood pressure detectors, are bulky, inconvenient to carry, and often provide inaccurate readings due to space constraints and mechanical alignment issues in electronic devices like smartphones.

Innovation Solution

A compact biological characteristic information detection device incorporating a pressure detection module with a thin cantilever beam and a photo plethysmography (PPG) detection module, which uses a cantilever beam with strain gauges and a PPG signal to accurately detect biological parameters like blood pressure, heart rate, and oxygen levels within a miniaturized electronic device, such as a smartwatch, without requiring additional space or complex auxiliary structures.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a traditional blood pressure detection device is used, then detection accuracy can be achieved, but the device becomes bulky and inconvenient to carry

Engineering Contradiction:
Improvedetection accuracyVSAvoiddevice size
Core Design Contradiction:
Measurement precisionVSVolume of moving object

Solution Approach 1:

The patent combines the blood pressure detection function with the existing smartphone hardware components. The pressure sensor is integrated into the smartphone's existing structure, and the detection function is merged with the phone's processing capabilities, eliminating the need for a separate bulky detection device while maintaining accuracy.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent makes the smartphone serve multiple functions: it acts as both a communication device and a biological characteristic detection device. The existing smartphone hardware (camera, processor, display) is utilized for detection purposes, making the device universal and eliminating the need for dedicated separate equipment.

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

2Volume of moving object

If the internal space of the electronic device is limited, then the device can be made thinner and more compact, but accurate detection of biological characteristic information becomes difficult

Engineering Contradiction:
Improvedevice thicknessVSAvoiddetection accuracy
Core Design Contradiction:
Volume of moving objectVSMeasurement precision

Solution Approach 1:

The pressure sensor is merged with the existing smartphone structure, utilizing available space efficiently. The sensor is positioned to work with existing hardware components, and the detection algorithm is optimized to compensate for the limited space, maintaining accuracy despite the compact form factor.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent changes the detection parameters and algorithms to adapt to the limited internal space. By optimizing the pressure sensor positioning, light source intensity, and signal processing parameters, the system achieves accurate biological characteristic detection within the constrained space of a thin smartphone.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If a transducer is placed in mechanical communication with a vein or artery, then blood pressure can be measured, but errors are introduced due to alignment, applanation, calibration, and contact-based stress

Engineering Contradiction:
Improveblood pressure measurement accuracyVSAvoidmeasurement reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent replaces the traditional mechanical contact-based transducer system with an optical measurement system. Instead of placing a transducer directly on the vein or artery, the system uses a camera to capture images of the blood vessel and analyzes changes in light transmission or reflection to determine blood pressure, eliminating mechanical contact errors.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an intermediary optical field between the measurement device and the blood vessel. Instead of direct mechanical contact, the system uses light as an intermediary to interact with the blood vessel, and the optical signals are processed to derive blood pressure information, avoiding the alignment and contact stress issues of direct mechanical measurement.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 device enables accurate detection of biological characteristics with high precision and convenience, overcoming the limitations of size and accuracy in existing devices by utilizing a miniaturized cantilever beam structure and integrated PPG detection, ensuring reliable readings in a compact form factor.

Implementation Method 1

a pressure detection module, including a cantilever beam and a pressure sensor, where the pressure sensor is fixed on the cantilever beam

Methodology Applied
Scientific EffectPiezoresistive Effect: Piezoresistive Effect

Implementation Method 2

a photo plethysmography (PPG) detection module, arranged at the elastic arm and configured to detect a PPG signal of a user

Methodology Applied
Scientific EffectPhotoelectric Effect: Photoelectric Effect

Data Source

PatentEP4039183B1Biometric information detection device and electronic apparatus
Publication Date: 2023.10.18 SHENZHEN GOODIX TECH CO LTD
  • EP4039183B1 patent drawingFigure 1~3
  • EP4039183B1 patent drawingFigure 4~6
  • EP4039183B1 patent drawingFigure 7~8

AI summary

An embodiment of the present application provides a biological characteristic information detection device and an electronic device. The biological characteristic information detection device is applied to the electronic device and includes: a pressure detection module including a cantilever beam and a pressure sensor, where the pressure sensor is fixed on a surface of the cantilever beam, the cantilever beam includes an elastic arm and a fixed base, the fixed base is fixed in the electronic device, and the elastic arm is suspended in the air; and a PPG detection module arranged on the elastic arm and configured to detect a PPG signal of a user when the user presses the electronic device, where when the user presses the electronic device, a pressure signal applied to the electronic device by the user is transmitted to the cantilever beam through the PPG detection module, so that the pressure sensor detects the pressure signal, and the pressure signal and the PPG signal are used to detect biological characteristic information of the user.