Under-Display Fingerprint Recognition Using Mutual and Self-Capacitance
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Solution Overview
Problem
Current fingerprint recognition technologies in touch displays increase screen thickness, complicate manufacturing processes, and raise costs, negatively impacting user experience.
Innovation Solution
A touch display device with a touch recognition module comprising a first electrode layer, an insulating layer, and a second electrode layer, where the first electrode layer includes touch electrodes, and the second electrode layer includes touch and fingerprint recognition electrodes that form mutual and self-capacitance respectively for touch detection and fingerprint recognition, integrated with a driver module for pulse control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a plug-in structure is used for fingerprint recognition, then fingerprint recognition function is achieved, but screen thickness increases and device complexity increases
Solution Approach 1:
The patent combines the fingerprint recognition module with the display panel by integrating the fingerprint recognition electrodes directly into the display panel's electrode layers. This merging eliminates the need for separate plug-in structures, thereby achieving fingerprint recognition functionality while maintaining thin screen thickness.
Solution Approach 2:
The display panel's electrode layers are designed to serve dual functions: touch sensing and fingerprint recognition. The first and second electrode layers can function as both touch electrodes and fingerprint recognition electrodes, eliminating the need for dedicated fingerprint recognition components and reducing overall device thickness.
2Adaptability or versatility
If a plug-in structure is used for fingerprint recognition, then fingerprint recognition function is achieved, but manufacturing process complexity increases and manufacturing cost increases
Solution Approach 1:
The fingerprint recognition module is merged with the display panel manufacturing process. The fingerprint recognition electrodes are formed using the same thin-film deposition and patterning processes as the display panel electrodes, eliminating the need for separate assembly steps and reducing manufacturing complexity.
Solution Approach 2:
The same electrode layers and manufacturing processes are used for both display panel fabrication and fingerprint recognition module fabrication. This universal approach allows both components to be produced in the same production line using identical materials and processes, significantly simplifying manufacturing.
3Measurement precision
If separate fingerprint recognition module is used, then fingerprint recognition is achieved, but device thickness increases
Solution Approach 1:
The fingerprint recognition electrodes are nested within the display panel's existing electrode structure. The first and second electrode layers that form the display panel also serve as the fingerprint recognition electrodes, with the fingerprint recognition area positioned adjacent to the touch area within the same panel structure.
Solution Approach 2:
The patent uses mutual capacitance and self-capacitance measurement methods to detect fingerprint features in the electrical dimension rather than requiring physical separation. By measuring capacitance changes between electrode layers when a fingerprint is present, the system achieves fingerprint recognition without increasing physical thickness.
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 solution reduces device thickness and manufacturing costs, enabling seamless integration of fingerprint recognition under the screen and improving user experience by using mutual and self-capacitance for effective touch and fingerprint detection.
Implementation Method 1
during fingerprint recognition, the fingerprint recognition electrodes form self-capacitance for recognizing a fingerprint
Implementation Method 2
during touch sensing, the first touch electrodes, the second touch electrodes, and the fingerprint recognition electrodes cooperatively form mutual capacitance for touch detection
Data Source
AI summary
A touch display device includes a display panel and a touch recognition module. The touch recognition module includes a first electrode layer disposed on the display panel, an insulating layer disposed on both the first electrode layer and the display panel, and a second electrode layer disposed on the insulating layer. The first electrode layer includes a plurality of first touch electrodes spaced apart from each other, and the second electrode layer includes a touch area and a fingerprint recognition area adjacent to the touch area.