Sensing Pixel Driving Circuit for Under-Display Biometric Recognition
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Solution Overview
Problem
The integration of photo-diodes for biometric recognition in electronic devices, such as fingerprint identification, complicates the reduction of the peripheral area of the display panel due to the combined circuitry for driving the photo-diode and display panel, making it difficult to minimize this area.
Innovation Solution
A method and device for driving sensing pixels using readout and reset scan signals, where readout signals are provided in a first order and reset signals in a second order, allowing for efficient operation and potentially reducing the components and area required for the driving circuit by using a single set of shift registers to generate these signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate circuits are used to drive the photo-diode and display panel, then the biometric recognition function is achieved, but the peripheral area width cannot be reduced
Solution Approach 1:
The patent combines the driving circuits for the photo-diode sensing pixels and the display panel into a single integrated circuit structure. The sensing pixels share the same scan signal lines and data signal lines as the display pixels, allowing one circuit to control both sensing and display functions simultaneously, thereby reducing the peripheral area width while maintaining biometric recognition capability
Solution Approach 2:
The driving circuit is designed with multi-functionality to serve both the display panel and the photo-diode sensing pixels. The same scan signal generation circuitry and data signal lines are used for both sensing operations (fingerprint recognition) and display operations, making the circuit universal and eliminating the need for separate dedicated circuits
2Adaptability or versatility
If multiple separate driving circuits are used for sensing and display, then functional independence is maintained, but device complexity increases
Solution Approach 1:
The patent merges the driving circuits for sensing and display functions into a single integrated circuit architecture. The scan signal lines and data signal lines are shared between sensing pixels and display pixels, reducing the number of separate circuits while maintaining functional independence through sequential operation modes
3Measurement precision
If separate scan signal lines are used for readout and reset operations, then operational precision is improved, but the number of signal lines increases
Solution Approach 1:
The scan signal lines are designed with multi-functionality to serve both readout and reset operations. The same scan signal lines that are used for reading sensor data are also used for resetting the sensing pixels, eliminating the need for separate dedicated reset scan lines and reducing the overall number of signal lines while maintaining operational precision
Data Source
AI summary
Sensing pixels each store a sensing voltage level. A method for driving the plurality of sensing pixels includes providing a plurality of readout scan signals to the plurality of sensing pixels, and providing a plurality of reset scan signals to the plurality of sensing pixels. One of the plurality of readout scan signals enables one of the plurality of sensing pixels to output the sensing voltage level stored in the one of the plurality of sensing pixels. One of plurality of reset scan signals resets the sensing voltage level stored in one of the plurality of sensing pixels. An nth reset scan signal of the plurality of reset scan signals is started behind an nth readout scan signal of the plurality of readout scan signals in time domain.