Active Stylus Uplink Signal Interference Reduction
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Solution Overview
Problem
As touch display panels increase in size, interference from other body parts such as the palm or fingers can disrupt the uplink signals intended for active styluses, leading to reduced signal quality and potential interruptions in communication.
Innovation Solution
A driving method and circuit for touch display panels that selectively transmit uplink signals to specific regions on the panel, while transmitting anti-interference signals to other areas, thereby reducing interference and enhancing signal quality for active styluses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the touch display panel size is increased, then the display area is expanded, but the interference from other body parts to the uplink signal increases
Solution Approach 1:
The touch display panel is divided into multiple independent drive regions, each capable of transmitting signals separately. This segmentation allows the system to transmit uplink signals only to the region where the active stylus is located, preventing other body parts from receiving and re-transmitting the signals, thus resolving the interference problem while maintaining large panel size
Solution Approach 2:
Different regions of the touch display panel are assigned different signal transmission characteristics. The region containing the active stylus receives the full uplink signal, while other regions receive anti-interference signals or no signal at all. This local differentiation ensures that only the intended target receives the communication signal, eliminating interference from other body parts
2Reliability
If uplink signals are transmitted to all regions, then complete coverage is achieved, but signal interference from body parts increases
Solution Approach 1:
The signal transmission is segmented into multiple independent regions. Only the region containing the active stylus transmits the full-strength uplink signal, while other regions transmit anti-interference signals. This maintains complete spatial coverage for reliability while preventing interference from body parts that would otherwise receive and re-transmit signals
Solution Approach 2:
Anti-interference signals are introduced as intermediary signals in regions where no active stylus is present. These signals prevent other body parts from receiving and re-transmitting the main uplink signal, thereby eliminating the interference pathway while maintaining signal transmission to the intended target
3Object-affected harmful factors
If anti-interference signals are transmitted to non-first regions, then interference is reduced, but signal-to-noise ratio may be affected
Solution Approach 1:
Different signal qualities are applied to different regions: the first region (containing the active stylus) receives the full-strength uplink signal with high signal-to-noise ratio, while non-first regions receive anti-interference signals. This local quality differentiation ensures that the active stylus receives optimal signal quality while other regions contribute only noise-reducing signals
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 approach improves the signal-to-noise ratio of uplink signals received by active styluses, ensuring reliable communication and reducing interference from other body parts, thus enhancing the sensing effect and preventing signal loss.
Implementation Method 1
When the active stylus transmits a DL signal, the capacitance value of a touch sensing electrode changes accordingly
Implementation Method 2
Based on the physical characteristics that the human body is a conductor, when the user uses the active stylus, the UL signal transmitted from the TDDI chip through the touch sensing electrodes will not only be received by the active stylus, but also received by the other body parts of the user and transmitted to the stylus shell
Data Source
AI summary
Provided are a driving method of a touch display panel, a driving circuit and a touch display device. The driving method includes: obtaining a touch position of an active stylus; determining a first region on the touch display panel based on the touch position of the active stylus; and transmitting an uplink (UL) signal to touch sensing electrodes in the first region and transmitting an anti-interference signal to the touch sensing electrodes in at least a part of the region except for the first region on the touch display panel during an UL transmission period, wherein the UL signal transmitted to the touch sensing electrodes in the first region during the UL transmission period is for transmission to the active stylus.