In-Display Fingerprint Sensor Timing Control
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Solution Overview
Problem
In in-display fingerprint sensing technologies, the integration of display driving periods and fingerprint sensing periods is challenging due to the embedded nature of the fingerprint sensor array within the display panel, affecting the independent operation of display and fingerprint sensing functions.
Innovation Solution
A display apparatus with a driving circuit that divides the display frame period into unit periods, including both display driving and fingerprint sensing periods, allowing for the resetting and sampling of fingerprint sensors during designated periods to optimize the timing relationship between display and fingerprint operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the fingerprint sensor array is embedded in the display panel (in-display fingerprint sensing), then the overall thickness of the display apparatus is reduced, but the operation of display function and fingerprint sensing function are influenced by each other, making timing arrangement challenging
Solution Approach 1:
The display frame period is segmented into multiple unit periods, with each unit period containing at least one fingerprint sensing period and one or both of display driving periods and touch sensing periods. This segmentation allows independent control and timing arrangement of different functions within the overall display frame period, resolving the timing conflict while maintaining the thin profile of in-display sensing.
Solution Approach 2:
The patent implements dynamic timing arrangement where the driving circuit can flexibly allocate different unit periods for fingerprint sensing, display driving, and touch sensing operations. This dynamic scheduling allows the system to adaptively manage the interactions between embedded functions, reducing timing complexity while maintaining the thickness benefits of in-display integration.
2Productivity
If the display frame period is divided into multiple unit periods with fingerprint sensing periods, then the fingerprint sensing operation can be synchronized with display driving, but the display driving period is interrupted by fingerprint sensing operations
Solution Approach 1:
The patent employs periodic fingerprint sensing operations within the display frame period, where fingerprint sensing is performed at specific intervals (unit periods) rather than continuously. This periodic approach allows the display driving to proceed with minimal interruption, while still achieving efficient fingerprint sensing through repeated sampling at designated times.
Solution Approach 2:
The patent ensures continuous fingerprint sensing capability by dividing the display frame period into multiple unit periods, each containing fingerprint sensing periods. This continuous periodic sampling maintains sensing efficiency while allowing display driving to operate continuously in parallel, minimizing interruptions to either function.
3Speed
If multiple sensors in the fingerprint sensor array are driven simultaneously, then the sensing speed is improved, but the circuit complexity and interference between sensors increase
Solution Approach 1:
The fingerprint sensor array is divided into multiple groups or rows, with sensors driven in sequential batches rather than all simultaneously. Each unit period drives a subset of sensors, reducing circuit complexity and interference while maintaining overall sensing speed through parallel processing of multiple sensor groups within the same display frame period.
Data Source
AI summary
A display apparatus and an fingerprint sensing method thereof are provided. A display panel of the display apparatus has a pixel circuit array, an in-display touch sensor array, and an in-display fingerprint sensor array. A driving circuit drives the in-display fingerprint sensor array to read a fingerprint image. A current display frame period is divided into a plurality of unit periods, each of the unit periods includes at least one fingerprint sensing period and one or both of a display driving period and a touch sensing period. The driving circuit resets a current fingerprint sensor in the in-display fingerprint sensor array during a first fingerprint sensing period among these fingerprint sensing periods of the first display frame period. The driving circuit reads a sensing result of the current fingerprint sensor during a second fingerprint sensing period succeeding to the first fingerprint sensing period.