Fingerprint Sensor Integrated in Touch Display via Capacitive Coupling
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Solution Overview
Problem
Fingerprint sensors integrated into electronic devices often require separate authentication steps, which can be inconvenient and slow down device operation, especially when performing other tasks.
Innovation Solution
An electronic device with a touch display incorporating a finger biometric sensor that includes an interconnect layer with transparent conductive traces and a sensing layer capacitively coupled to the touch display, allowing for simultaneous fingerprint sensing during touch display operation, with a transparent dielectric layer and vias for coupling, and a finger sensing IC for efficient data acquisition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fingerprint sensor is integrated into the electronic device, then authentication capability is improved, but authentication time increases due to separate authentication steps
Solution Approach 1:
The patent combines the touch display functionality with fingerprint sensing capability into a single integrated structure. The touch display includes transparent conductive layers that serve dual purposes: touch sensing and fingerprint biometric sensing. This merging eliminates the need for separate authentication steps, allowing users to authenticate naturally while interacting with the display, thereby reducing authentication time while maintaining reliability
Solution Approach 2:
The touch display is designed to perform multiple functions simultaneously: it serves as both a display interface and a biometric authentication sensor. The transparent conductive layers and sensing pixels are configured to detect both touch interactions and fingerprint patterns, enabling the device to handle various user interactions through a single unified interface, thus improving efficiency without compromising authentication capability
2Speed
If a fingerprint sensor is integrated into the touch display, then authentication speed is improved, but device complexity increases
Solution Approach 1:
The patent merges the fingerprint sensor with the touch display structure, sharing common components such as transparent conductive layers, dielectric layers, and sensing pixels. This integration approach avoids adding separate sensor modules, thereby maintaining relatively simple device architecture while achieving fast authentication speeds through the unified sensing mechanism
Solution Approach 2:
The patent uses uniform transparent conductive materials (such as ITO - indium tin oxide) for both the touch display electrodes and the fingerprint sensor electrodes. This homogeneity in material selection simplifies the manufacturing process and reduces structural complexity, as the same material deposition and patterning techniques can be used for both functions, while still enabling high-speed authentication
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
Enables quick and seamless biometric authentication without interrupting device operation, enhancing user experience by integrating fingerprint sensing into the touch display, improving modulation and supporting high-frequency operations through the use of indium-tin-oxide (ITO) materials.
Implementation Method 1
an array of transparent conductive finger biometric sensing pixels capacitively coupled to the at least one transparent conductive layer of the touch display
Data Source
AI summary
An electronic device may include a touch display that includes at least one display layer, and at least one transparent conductive layer thereon defining touch sensing pixels. The electronic device may also include a finger biometric sensor carried by the touch display and that may include an interconnect layer that includes transparent conductive traces, and a finger biometric sensing layer adjacent the interconnect layer and that includes an array of transparent conductive finger biometric sensing pixels capacitively coupled to the at least one transparent conductive layer of the touch display. The finger biometric sensor may also include a transparent dielectric layer between the interconnect layer and the finger biometric sensing layer, and transparent conductive vias extending through the transparent dielectric layer and coupling the array of transparent conductive finger biometric sensing pixels to respective ones of the transparent conductive traces.