Touch Capacitance Energy Harvesting for Biosensors
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Solution Overview
Problem
Small body-worn devices struggle to efficiently harness energy from ambient vibrations and fluid flow, and existing methods to utilize human motion for power generation are inefficient in delivering energy to devices on the body or in the environment.
Innovation Solution
A touch capacitance transduced energy harvesting system that uses a touch sensing electrode array and energy harvesting circuitry to convert the kinetic energy of a movable conductive object, such as a human finger, into direct current, which is then stored as DC voltage, enabling the powering of low-power electronic devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If ambient vibrations and fluid flow are used for energy harvesting, then energy can be extracted from the environment, but small body-worn devices cannot efficiently utilize these sources
Solution Approach 1:
The patent replaces mechanical vibration-based energy harvesting with electrostatic transduction. Instead of using mechanical resonators that require ambient vibrations, the system uses a movable electrode that responds to any motion (including finger taps) by changing capacitance, thereby generating electrical energy through electrostatic field changes rather than mechanical energy conversion.
Solution Approach 2:
The system changes the operating parameter from mechanical vibration frequency to capacitance variation. The movable electrode's position changes cause direct capacitance modulation, converting kinetic energy to electrical energy through electrostatic transduction. This allows the device to harvest energy from any motion regardless of frequency or amplitude, making it adaptable to small body-worn devices.
2Power
If human motion is used for power generation through piezoelectric or triboelectric transduction, then energy can be harvested from body movements, but it is difficult to deliver this power to useful devices
Solution Approach 1:
The patent merges the energy harvesting function with the touch interface function into a single integrated system. The same movable electrode that detects touch input also generates electrical energy through capacitance changes. This eliminates the need for separate power delivery mechanisms and allows direct use of the touch interaction for both control and power generation.
Solution Approach 2:
The system uses the user's own touch interactions to generate the power needed to operate the device. Every finger tap or movement on the touch surface simultaneously serves as both the control input and the energy source, making the device self-powered through user interaction without requiring external power delivery infrastructure.
3Measurement precision
If a touch sensing electrode array is used to detect finger motion, then touch input can be detected, but the system can also harvest electrical energy from the capacitance changes
Solution Approach 1:
The patent makes the touch sensing electrode array perform dual functions: detecting touch input and generating electrical energy. The same capacitance changes that enable precise touch detection are also exploited to harvest energy through the energy harvesting circuitry. This multi-functionality eliminates the need for separate components and reduces overall system complexity despite adding energy harvesting capability.
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 system effectively harvests energy from human motion, providing a reliable power source for low-power devices like biosensors by leveraging capacitance changes caused by finger movement, overcoming previous inefficiencies in energy transfer and storage.
Implementation Method 1
When a movable conductive object (e.g., a human finger) moves toward or away from the touch sensing electrode array, capacitance of the touch sensing electrode array increases and decreases accordingly
Implementation Method 2
transducing a direct current (DC) current in the touch sensing electrode array
Implementation Method 3
the energy harvesting circuitry can be configured to harvest electric energy from the DC current to generate and store a DC voltage
Data Source
AI summary
Aspects disclosed in the detailed description include a touch capacitance transduced energy harvesting system. The energy harvesting system includes a touch sensing electrode array and energy harvesting circuitry coupled to the touch sensing electrode array. When a movable conductive object (e.g., a human finger) moves toward or away from the touch sensing electrode array, capacitance of the touch sensing electrode array increases and decreases accordingly, thus transducing a direct current (DC) current in the touch sensing electrode array. As such, the energy harvesting circuitry can be configured to harvest electric energy from the DC current to generate and store a DC voltage. By harvesting the electric energy transduced from the kinetic energy of the movable conductive object, it is possible to power a low-power electronic device (e.g., a biosensor) with motions already used for interfacing with the low-power electronic device.