In-Display Fingerprint Driving Method for Capacitive Interference Reduction
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Solution Overview
Problem
In-display fingerprint recognition systems face interference between display, touch, and fingerprint recognition operations due to capacitive coupling between touch sensing and fingerprint sensing layers, affecting the accuracy of display and touch signals.
Innovation Solution
A fingerprint recognition driving method that periodically arranges time periods for display and touch operations and fingerprint recognition, generating a reset signal during display and touch periods to reduce capacitive load and interference, and uses an anti-loading driving signal synchronized with touch signals to minimize coupling capacitance effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If fingerprint recognition circuit is embedded inside display panel, then display size is reduced, but interference between display/touch operations and fingerprint recognition operations increases
Solution Approach 1:
The patent segments the operation time into distinct periods: display periods, touch sensing periods, and fingerprint recognition periods. By time-division multiplexing these functions, the system eliminates mutual interference while maintaining all functionalities. The controller sequentially activates different circuits in different time slots, preventing simultaneous operation conflicts.
Solution Approach 2:
The patent implements periodic switching between display/touch operations and fingerprint recognition operations. The controller periodically activates the fingerprint recognition circuit during dedicated recognition periods, while displaying normal content during display periods. This periodic action ensures that capacitive coupling interference is minimized by preventing simultaneous activation of conflicting circuits.
2Adaptability or versatility
If touch sensing layer and fingerprint sensing layer are superimposed, then in-display functionality is achieved, but capacitive load increases due to coupling capacitance
Solution Approach 1:
The patent extracts the fingerprint sensing function from the continuous operation state and isolates it into specific recognition periods. During non-recognition periods, the fingerprint sensing circuit is deactivated or placed in a low-power state, removing its capacitive load effect on the display and touch circuits. This extraction eliminates the harmful capacitive coupling during display and touch operations.
3Ease of operation
If fingerprint recognition operates simultaneously with display and touch, then user experience is improved, but signal accuracy decreases due to interference
Solution Approach 1:
The patent performs preliminary actions by detecting touch events first, then triggering fingerprint recognition only when needed. The controller monitors touch sensor output and initiates fingerprint recognition operations only after detecting a valid touch event, rather than continuously operating the fingerprint circuit. This preliminary detection approach maintains signal accuracy by activating the fingerprint circuit only when necessary.
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 method reduces interference between display, touch, and fingerprint recognition operations, improving the accuracy of display and touch signals by controlling voltages and minimizing capacitive load during simultaneous operations.
Implementation Method 1
One layer of a touch sensing layer and a fingerprint sensing layer may be superimposed on the other layer, and the two layers are close to each other, resulting in a huge capacitive load caused by coupling capacitance between the touch sensing layer and the fingerprint sensing layer.
Data Source
AI summary
The present disclosure provides a fingerprint recognition driving method for a display panel, the display panel including a fingerprint recognition circuit, a fingerprint recognition driving circuit and a controller, the fingerprint recognition driving circuit being used to provide a fingerprint recognition driving signal to the fingerprint recognition circuit, the fingerprint recognition driving method including: periodically arranging, by the controller, time periods for display and touch in a case that the controller does not receive a fingerprint recognition start signal; periodically arranging, by the controller, time periods for display and touch and time periods for fingerprint recognition at intervals in a case that the controller receives the fingerprint recognition start signal; generating, by the controller, a first fingerprint recognition reset signal during at least one time period for display and touch, and the fingerprint recognition driving circuit being reset under the control of the first fingerprint recognition reset signal.