Multi-mode Voltage Control for Touchscreen Crosstalk
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Solution Overview
Problem
Capacitive touch screens face interference and errors due to crosstalk between display and touch sensing systems, which can lead to inaccurate touch detection, especially as touch sensing circuitry becomes more integrated with display pixel stackups.
Innovation Solution
Implementing a multi-mode power system that applies different voltage modes for display and touch sensing phases, with distinct voltage levels to reduce crosstalk and minimize interference, allowing for independent adjustment of electrical characteristics to suit each operational phase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If touch sensing circuitry is integrated with display pixel stackups, then device complexity is reduced and manufacturing is simplified, but crosstalk between display and touch sensing systems increases causing measurement errors
Solution Approach 1:
The patent segments the operational timeline into distinct display phases and touch sensing phases, applying different voltage modes during each phase. This temporal segmentation allows the integrated circuitry to perform display functions during display phases and touch sensing functions during touch phases, minimizing crosstalk while maintaining integration benefits.
Solution Approach 2:
The patent changes voltage parameters dynamically by switching between first voltage modes (during display phases) and second voltage modes (during touch sensing phases). This parameter change approach optimizes electrical characteristics for each operational mode, reducing crosstalk interference while maintaining the integrated structure.
2Device complexity
If single voltage mode is used for both display and touch sensing, then device complexity is reduced, but crosstalk increases and touch sensing accuracy deteriorates
Solution Approach 1:
The patent implements dynamic voltage control by switching between different voltage modes based on the operational phase. The system dynamically adjusts voltage parameters during operation, transitioning from first voltage modes during display phases to second voltage modes during touch sensing phases, thereby optimizing performance without excessive complexity.
Solution Approach 2:
The patent employs periodic switching between display phases and touch sensing phases, with each phase utilizing appropriately optimized voltage modes. This periodic action allows the system to maintain different voltage characteristics for different functions while operating within a unified integrated structure.
3Measurement precision
If different voltage modes are applied for display and touch sensing phases, then crosstalk is reduced and touch sensing accuracy is improved, but device complexity and power management requirements increase
Solution Approach 1:
The patent designs the power system with multi-functionality, where the same power management infrastructure supports both display phases and touch sensing phases by switching between different voltage modes. This universal approach reduces the need for completely separate power systems, thereby limiting complexity increase while achieving improved touch sensing accuracy.
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 effectively reduces crosstalk and error mechanisms, enhancing the accuracy of touch sensing by isolating touch sensing circuitry during the touch phase and optimizing electrical characteristics for improved signal integrity.
Implementation Method 1
Capacitive touch sensor panels can be formed from a matrix of drive and sense lines of a substantially transparent conductive material
Implementation Method 2
A display system can update an image displayed by the display pixels during the display phase. Each of the one or more voltages can be applied to the touch screen at the corresponding first voltage level during the updating of the image
Data Source
AI summary
Operating touch screens by applying more than one voltage modes, including a first voltage mode corresponding to a display phase and a second voltage mode corresponding to a touch sensing phase, is provided. An integrated touch screen device can include a multi-mode power system that can select a first voltage mode corresponding a display phase and a second voltage mode corresponding to a touch sensing phase. Each of one or more voltages can be applied to the touch screen at the corresponding first voltage level during the updating of the image. A touch sensing system can sense touch during a touch sensing phase. Each of one or more voltages can be applied to the touch screen at the corresponding second voltage level during the sensing of touch.