Driving Circuit Multiplexer Touch Fingerprint Sensing
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Solution Overview
Problem
The increasing demand for touch-type input processing in display devices has led to a need for a driving circuit that can perform multiple sensing functions, such as touch and fingerprint sensing, while also displaying images, without requiring separate circuits for each function, thereby reducing the number of driving circuits needed.
Innovation Solution
A driving circuit that includes a common electrode driving controller, a pixel electrode driving controller, and a sensing unit, capable of applying voltages and sensing capacitance changes during different time intervals to perform display driving, touch sensing, and additional sensing functions like fingerprint recognition using a common electrode and pixel electrode within a single circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate driving circuits are used for touch sensing and fingerprint sensing, then sensing accuracy is improved, but device complexity increases
Solution Approach 1:
The patent combines touch sensing and fingerprint sensing functions into a single driving circuit. The driving circuit includes a sensing unit with a multiplexer that can switch between connecting to a common electrode for touch sensing and a pixel electrode for fingerprint sensing, allowing both sensing functions to share the same driving circuit while maintaining sensing accuracy
Solution Approach 2:
The driving circuit is designed with multi-functionality to perform both touch sensing and fingerprint sensing operations. The sensing unit can be configured through the multiplexer to execute different sensing protocols depending on the operational mode, enabling one circuit to fulfill multiple sensing purposes without requiring separate dedicated circuits for each function
2Device complexity
If a single driving circuit performs multiple sensing functions, then device complexity is reduced, but sensing accuracy deteriorates
Solution Approach 1:
The sensing unit is segmented into distinct operational modes handled by the multiplexer. The multiplexer switches between different electrode connections (common electrode for touch sensing, pixel electrode for fingerprint sensing) and different sensing protocols, allowing the single driving circuit to maintain high sensing accuracy by dedicating specific circuit paths and processing methods to each sensing function
Solution Approach 2:
The driving circuit employs dynamic switching through the multiplexer to adapt its configuration based on the required sensing function. The circuit can dynamically reconfigure its internal connections and sensing parameters to optimize performance for either touch sensing or fingerprint sensing, maintaining high accuracy despite performing multiple functions within a single circuit
3Adaptability or versatility
If time is divided into display driving period and sensing periods, then multiple functions are performed, but time efficiency decreases
Solution Approach 1:
The driving circuit operates in periodic cycles, alternating between display driving periods and sensing periods (first sensing period for touch sensing, second sensing period for fingerprint sensing). This periodic operation allows the system to perform multiple functions by systematically switching between different operational modes at predetermined time intervals, ensuring both display and sensing functions are executed regularly
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 a single driving circuit to perform display driving, touch sensing, and additional sensing functions like fingerprint touch sensing, improving accuracy and reducing the need for multiple sensing circuits, thus meeting user demands for diverse touch-type input processing.
Implementation Method 1
a sensing unit, which is connected with the common electrode driving controller in a first sensing period and with the pixel electrode driving controller in a second sensing period and is configured to sense a change in capacitance between the common electrode or pixel electrode and an object that is in contact with the display panel
Data Source
AI summary
Provided is a driving circuit included in a touch display device, which is capable of performing display driving, touch sensing, and additional sensing in addition to the touch sensing. The driving circuit includes a common electrode driving controller, a pixel electrode driving controller, and a sending unit. The common electrode driving controller is configured to apply a common voltage to a common electrode during a display-driving period. The pixel electrode driving controller is configured to apply a data voltage to a pixel electrode during the display-driving period. The sensing unit is connected to the common electrode driving controller during a first sensing period and to the pixel electrode driving controller during a second sensing period. The sensing unit is configured to sense a change in capacitance between the common electrode or pixel electrode and an object that is in contact with the display panel.