Display Driver Circuit Time-Division Multiplexing for Fingerprint Sensing
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Solution Overview
Problem
Existing electronic circuits driving display panels with integrated touch and fingerprint sensors face challenges in maintaining a small fan-out area and frame border size while ensuring high fingerprint image resolution, due to the complexity of signal transmission and multiplexing requirements.
Innovation Solution
The electronic circuit employs a switch circuit with first and second switch elements to separately transmit display driving signals and receive fingerprint sensing signals in different time intervals, using a shared transmission line, and the display panel incorporates a switch circuit with a 1:5 multiplexer to maintain image resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple I/O nodes and complex routing are used for signal transmission between the electronic circuit and the display panel, then the display driving function and fingerprint sensing function can be independently implemented, but the width of the fan-out area and the frame border size increase
Solution Approach 1:
The patent merges the display driving signal transmission path and the fingerprint sensing signal transmission path into a shared transmission line. The same physical connection is used for both functions at different time intervals, reducing the number of separate I/O nodes and routing paths required, thereby decreasing the fan-out area width while maintaining reliable signal transmission for both functions
Solution Approach 2:
The patent implements dynamic time-division multiplexing where the transmission line dynamically switches between carrying display driving signals during display time intervals and fingerprint sensing signals during fingerprint sensing time intervals. This dynamic allocation allows a single static physical connection to serve multiple functions, reducing the fan-out area while ensuring reliable signal transmission for each function when needed
2Adaptability or versatility
If 1:4 multiplexers are used to receive red, green, blue and white display data, then the display panel can support RGBW pixels, but the resolution of the fingerprint image decreases
Solution Approach 1:
The patent implements dynamic switching between different multiplexer configurations based on the operational mode. During display time intervals, the multiplexer operates in 1:4 mode to support RGBW pixels. During fingerprint sensing time intervals, the same multiplexer switches to a higher-resolution configuration that prioritizes fingerprint image quality. This dynamic reconfiguration allows the system to achieve both high adaptability for different display modes and high measurement precision for fingerprint sensing
Solution Approach 2:
The patent segments the multiplexer functionality into different operational modes that are activated at different time intervals. The multiplexer is divided into distinct functional states: one state optimized for RGBW display data transmission and another state optimized for high-resolution fingerprint sensing. This segmentation allows each function to operate at its optimal performance level without compromising the other
Data Source
AI summary
An electronic circuit adapted to drive a display panel including touch sensors and fingerprint sensors is provided. The electronic circuit includes a switch circuit and a control circuit. The switch circuit includes a plurality of first switch elements and a plurality of second switch elements. The control circuit is configured to generate control signals for controlling the switch circuit, so as to control the electronic circuit to transmit the display driving signals from the first circuit to the data lines through a first part of the first switch elements in a first time interval, and control the electronic circuit to receive the fingerprint sensing signals from the fingerprint sensors of the display panel through the second switch elements in a second time interval.