Nanostructure Array Capacitive Sensor for High-Resolution Fingerprint and Pressure Detection
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Solution Overview
Problem
Existing fingerprint and pressure sensors lack the resolution and flexibility to accurately capture detailed biometric data due to limitations in sensor design and technology, particularly in compact and low-power consumption devices.
Innovation Solution
The use of individually addressable nanostructures in an array format, with a substrate and dielectric material, and a top electrode, generates an intense electric field to detect capacitance changes caused by fingerprint ridges and pressure, allowing for high-resolution fingerprint and pressure sensing with low power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional capacitive sensors are used, then the device can detect fingerprints, but the resolution is insufficient to capture detailed biometric data
Solution Approach 1:
The sensor is divided into an array of individually addressable nanostructures (such as carbon nanotubes or nanowires) arranged in a grid pattern. Each nanostructure acts as an independent sensing element, allowing high-resolution fingerprint detection through pixelated readout. This segmentation enables sub-micron spatial resolution while maintaining a relatively simple overall device structure.
Solution Approach 2:
The patent transitions from planar 2D capacitor plates to 3D vertically-oriented nanostructures. The nanostructures extend perpendicular to the substrate, creating a third dimension that increases the effective sensing area and electric field strength without increasing the device footprint, thereby achieving high resolution in a compact form factor.
2Volume of moving object
If sensor size is reduced for compact devices, then portability improves, but the ability to capture detailed biometric data deteriorates
Solution Approach 1:
By orienting nanostructures vertically rather than using planar electrodes, the patent achieves high sensing resolution within a thin profile. The vertical dimension provides increased capacitance and electric field strength without increasing lateral device dimensions, enabling compact yet high-resolution fingerprint sensing.
Solution Approach 2:
The sensor employs thin-film dielectric layers and flexible substrate materials, allowing the device to maintain small volume while preserving sensing performance. The thin-film structure enables high resolution in a compact, potentially flexible form factor suitable for mobile applications.
3Adaptability or versatility
If traditional sensors are used, then basic pressure detection is possible, but flexibility and comfort for prolonged use are limited
Solution Approach 1:
The patent uses flexible substrates and thin-film nanostructure arrays that can conform to curved surfaces and withstand bending. This flexibility improves user comfort for prolonged use while the robust nanostructure design maintains signal consistency and sensing reliability even when the device is flexed or deformed.
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 approach enables ultra-sensitive, compact, and flexible fingerprint and pressure sensors with sub-micron spatial resolution, reducing false signals and allowing for multiple sensors to be packed in a small area, enhancing security and precision in biometric applications.
Implementation Method 1
A voltage V is applied between the nanostructures and the top electrodes, an intense electric field is generated between the nanostructures and the top electrode
Implementation Method 2
The dielectric properties of the dielectric material are an important component in determining the capacitance/supercapacitance properties of the fingerprint device
Implementation Method 3
the ridges of the fingerprints make contact with the device causing a signal, (a change in the capacitance of the device) that can be detected using external circuits
Implementation Method 4
When a pressure is applied on the top protective layer, it deforms the top electrode causing a change in the distance between the nanostructures and the top electrode
Data Source
AI summary
An arrangement of individually addressable nanostructures (200) in an array format on a substrate (100) (non-conducting, flexible or rigid) with electrical portions (conducing) in the substrate where the electrical portions form electrical contacts with the nanostructures is utilized to form individually addressable nanostructures. The said nanostructures can be 1-1,000,000 nm in base size and range from 1-1,000,000 nm in height. The distance between the said nanostructures in the array can also range from 10-1,000,000 nm. The said nanostructures are covered in a dielectric material (300) (air, polymer, ceramic) that is at least 5-500,000 nm thicker than the height of the said nanostructures. The dielectric properties of the dielectric material are an important component in determining the capacitance/supercapacitance properties of the fingerprint device. A top electrode (400) is placed on the face of dielectric film opposite to the face in contact with the substrate where nanostructures are arranged. A top layer (500) (glass or Other robust material) is placed on top of the top metal electrode. A voltage V (900) is applied between the nanostructures (200) and the top electrodes (400), an intense electric field (600) is generated between the nanostructures (200) and the top electrode (400). The direction of the said electrical field is dependent on the polarity of the voltage applied. The electric capacitance (700) between the nanostructures and the top electrode as formed. When a finger (1000) is placed on the device, the ridges (1001) of the fingerprints make contact with the top layer (500) of the device causing a signal, (a change in the capacitance of the device) that can be detected using external circuits. The valleys (1002) of the finger do not make contact with the top layer (500) device and hence do not produce a signal. If a pressure is applied on the top layer (500), the distance between the top electrode (400) and the nanostructures (200) is reduced, causing a change in the capacitance, allowing measurement of pressure. Since the nanostructures (200) are distributed on a surface (2000) in sections (2010) we can obtain special resolution of pressure on a surface or gather fingerprints using a cost effective, low power, robust and stand-alone portable, miniature system.