Built-in Touch Screen Common Voltage Segmentation for Image Quality
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Solution Overview
Problem
Conventional display devices with built-in touch screens face image quality defects due to uneven common voltage distribution across touch electrodes, leading to local stains and screen vibrations, as the same common voltage is applied to all electrodes regardless of their position and length, which is inadequate for large-sized displays.
Innovation Solution
A display device with a built-in touch screen that includes a common voltage supplier generating multiple voltages and a switch circuit to adjust the supply of these voltages to touch electrodes or groups, ensuring different common voltages are applied based on position and length, and a compensator circuit to maintain voltage consistency and prevent image quality defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the same common voltage is applied to all touch electrodes, then the circuit design is simple, but local stains and screen vibrations occur due to uneven voltage distribution
Solution Approach 1:
The patent divides the touch electrode array into multiple groups (first touch electrode group, second touch electrode group, etc.) and applies different common voltages to each group. This segmentation allows independent voltage control for different regions, resolving the uneven voltage distribution issue while maintaining manageable circuit complexity through systematic grouping.
Solution Approach 2:
The patent implements local quality by supplying different common voltages to different touch electrode groups based on their specific positions and characteristics. Each touch electrode group receives a tailored common voltage that compensates for local variations in touch sensing line lengths and positions, thereby eliminating local stains and screen vibrations.
2Reliability
If different common voltages are supplied to touch electrodes, then image quality improves, but device complexity increases
Solution Approach 1:
The voltage supply system is segmented into multiple common voltage suppliers, each dedicated to supplying common voltage to a specific touch electrode group. This segmentation simplifies the control logic for each supplier while achieving the overall goal of differentiated voltage supply, balancing image quality improvement with manageable system complexity.
Solution Approach 2:
Each common voltage supplier is designed to perform multiple functions: generating the common voltage, supplying it to the designated touch electrode group, and maintaining voltage stability. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity while achieving differentiated voltage supply.
3Device complexity
If a single common voltage is used for large-sized displays, then the voltage supply system is simple, but local image quality defects cannot be resolved
Solution Approach 1:
The patent applies local quality by providing different common voltages to different touch electrode groups based on their specific positions within the large-sized display. This approach addresses local image quality defects caused by variations in touch sensing line lengths and positions, ensuring consistent display performance across the entire large display area.
Solution Approach 2:
The large display is segmented into multiple touch electrode groups, each receiving a customized common voltage. This segmentation enables precise control over local voltage distribution, resolving image quality issues in different regions of the large display while maintaining a structured and manageable voltage supply architecture.
Data Source
AI summary
A display device with a built-in touch screen according to the present disclosure includes a display panel, a data driver, a gate driver, a touch sensing unit, a common voltage supplier, and a switch circuit, and further includes a common voltage adjuster to supply different common voltages to touch electrodes of the display panel, thereby resolving a local stain or screen vibration problem occurring on the display panel. Further, a method for driving a display device with a built-in touch screen according to one embodiment includes: switching the display panel from a touch mode to a display mode, generating different common voltages, and supplying two or more of the different common voltages to a plurality of touch electrodes (TE) or groups of touch electrodes (TE), thereby resolving an image quality defect.