Display Panel Fingerprint Sensing Load Balancing via Dummy Pixels
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Solution Overview
Problem
Display panels with integrated fingerprint sensing functions face issues of inconsistent loading between sensing and non-sensing areas, affecting visual uniformity and touch sensing behavior due to the deployment of fingerprint sensing pixels, which leads to reduced visual effects and interference in touch sensing operations.
Innovation Solution
The implementation of a method and control circuit that utilizes dummy pixels in the non-sensing area, coupled to dummy lines, to generate loads equivalent to those in the sensing area, along with the application of anti-loading driving signals or floating configurations to control lines and dummy lines, ensuring uniform loading and minimizing interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If fingerprint sensing pixels are deployed in the sensing area, then fingerprint sensing function is achieved, but loading inconsistency between sensing and non-sensing areas occurs, reducing visual uniformity
Solution Approach 1:
The patent introduces dummy pixels in the non-sensing area that replicate the electrical loading characteristics of the fingerprint sensing pixels in the sensing area. These dummy pixels are electrically connected through dummy lines to control lines, creating a copy of the loading effect without the sensing functionality. This copying approach balances the total loading across the display panel, eliminating visual non-uniformity while preserving the fingerprint sensing capability in the designated sensing area.
2Adaptability or versatility
If fingerprint sensing pixels are deployed in the sensing area, then fingerprint sensing function is achieved, but touch sensing behavior is influenced, reducing sensing accuracy
Solution Approach 1:
The dummy pixels and dummy lines create a replicated electrical loading structure in the non-sensing area that mirrors the sensing area's loading characteristics. This copying of the electrical architecture ensures that the capacitive loading distribution is uniform across the entire display panel, which stabilizes the reference potential for touch sensing and eliminates interference from loading inconsistencies, thereby improving touch sensing accuracy.
3Stability of the object's composition
If dummy pixels are added to the non-sensing area to balance loading, then visual uniformity is improved, but device complexity increases
Solution Approach 1:
The dummy pixels replicate only the essential electrical loading characteristics of the sensing pixels without duplicating the full sensing functionality. This selective copying approach balances the electrical loading across the display panel to achieve visual uniformity, while the dummy pixels remain electrically isolated from the sensing signal path, thus avoiding the need for complex sensing circuitry in the non-sensing area.
4Stability of the object's composition
If control lines are configured to be floating or ALD signals are applied, then loading consistency is improved, but control circuit complexity increases
Solution Approach 1:
The patent implements anti-loading driving (ALD) signals that are specifically designed to counterbalance the capacitive loading effects in the non-sensing area. These ALD signals modify the voltage waveforms applied to the dummy lines, creating an electrical environment that compensates for the loading differences between sensing and non-sensing areas. This parameter adjustment approach achieves loading consistency through signal conditioning rather than structural modification.
Data Source
AI summary
The present invention provides a method of controlling a display panel having a sensing area and a non-sensing area. The sensing area includes a plurality of fingerprint sensing pixels, each of which is coupled to at least one control line. The non-sensing area includes a plurality of dummy pixels, each of which is coupled to at least one dummy line. The method includes steps of: applying a control signal on a first control line among the at least one control line or configuring the first control line to be floating, and applying a first anti-loading driving (ALD) signal corresponding to the control signal on a first dummy line among the at least one dummy line or configuring the first dummy line to be floating.