In-Cell Touch Display Voltage Equalization
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Solution Overview
Problem
Display devices with integrated in-cell type touch screens suffer from issues like block dimming and flickers due to voltage differences between driving and sensing electrodes during different operating modes.
Innovation Solution
A display device configuration where the touch IC applies a touch sensing reference voltage with the same level as the minimum voltage of the driving pulse, ensuring that both driving and sensing electrodes receive the same voltage level during touch driving mode, preventing luminance differences and flickers by maintaining consistent voltage levels across electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If different voltages are applied to driving and sensing electrodes during touch driving mode, then touch sensing function is enabled, but block dimming and flickers occur due to voltage differences
Solution Approach 1:
The patent applies equipotentiality by setting the touch sensing reference voltage equal to the minimum voltage of the driving pulse (Vref = Vgl). This ensures that during touch driving mode, both driving and sensing electrodes maintain the same voltage level, eliminating voltage differences that cause block dimming and flickers while preserving touch sensing functionality
Solution Approach 2:
The patent changes the voltage parameter relationship between driving and sensing electrodes. Instead of using arbitrary DC voltages, it specifically sets the reference voltage to match the minimum driving pulse voltage, thereby resolving the display quality issues while maintaining touch operation
2Illumination intensity
If common voltage is applied to both driving and sensing electrodes during display driving mode, then display quality is maintained, but touch sensing cannot be performed
Solution Approach 1:
The patent implements dynamic voltage switching where the voltage application mode changes based on operating requirements. During display mode, common voltage is applied; during touch mode, differential voltages are applied with Vref = Vgl. This dynamic adaptation allows the system to maintain display quality when needed and enable touch sensing when needed
3Ease of operation
If voltage levels between display driving mode and touch driving mode differ, then touch sensing is enabled, but flickers occur due to voltage transitions
Solution Approach 1:
By setting Vref = Vgl, the patent ensures that the voltage levels are equipotential during mode transitions. This eliminates abrupt voltage changes between display and touch modes, preventing flickers while maintaining the ability to perform touch sensing operations
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
Prevents block dimming and flickers by ensuring equal voltage application to driving and sensing electrodes, enhancing display quality and user experience in touch screen operations.
Implementation Method 1
a mutual capacitance to be generated between the touch driving area and the touch sensing area. Therefore, the related art display device measures the change of a mutual capacitance that occurs from a touch
Data Source
AI summary
A display device with integrated touch screen is provided. The display device may include a panel, a display driver IC, and a touch IC. The panel may include a plurality of driving electrodes and sensing electrodes. The display driver IC may apply a driving pulse to the driving electrodes and receive a plurality of sensing signals from the sensing electrodes when the panel operates in a touch driving mode, and, when the panel operates in a display driving mode, the display driver IC may apply a common voltage to the driving electrodes and sensing electrodes. The touch IC may generate the driving pulse and apply the driving pulse to the display driver IC, and may receive the sensing signals from the display driver IC to determine whether there is a touch. The touch IC may include a sensing unit sensing whether there is a touch.