VA Mode LCD Common Electrode Touch Sensing
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Solution Overview
Problem
Conventional LCD devices with on-cell type touch panels face challenges in achieving slimness due to the additional volume and complexity introduced by the touch panel, which complicates navigation and user interaction.
Innovation Solution
A display apparatus utilizing a common electrode on the upper substrate in a VA mode, which forms an electric field with the pixel electrode for image display and senses capacitance changes for touch input, incorporating touch sensing and driving electrodes, and a timing controller for alternating display and touch modes, thereby enabling touch functionality without the need for an additional touch panel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an on-cell type touch panel is added to the upper substrate, then touch sensing capability is improved, but the volume and thickness of the LCD device increase
Solution Approach 1:
The patent merges the touch sensing function with the display function by integrating the touch sensing electrode into the common electrode layer of the display panel. This allows the same electrode structure to serve dual purposes: displaying images when voltage is applied and sensing touch input through capacitance changes, thereby eliminating the need for a separate touch panel layer and reducing overall device volume
Solution Approach 2:
The common electrode is designed to perform multiple functions: it serves as the common electrode for liquid crystal display operation and simultaneously functions as the touch sensing electrode for detecting user input. This multi-functional design allows the device to maintain touch capability while avoiding additional volume from separate touch panel components
2Adaptability or versatility
If an on-cell type touch panel is added to the upper substrate, then touch sensing capability is improved, but the structural complexity increases
Solution Approach 1:
The patent combines the touch sensing electrode and common electrode into a single integrated structure. The common electrode is patterned to function as both the display common electrode and the touch sensing electrode, eliminating the need for separate electrode layers and reducing structural complexity
Solution Approach 2:
The common electrode structure is designed to serve dual functions: displaying images through electric field control and sensing touch input through capacitance detection. This universal design reduces the number of separate components needed, thereby simplifying the overall device structure
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 solution allows for slim and efficient touch-sensitive LCD devices by integrating touch functionality into the display panel, reducing volume and maintaining image quality by minimizing the duration of touch mode operation.
Implementation Method 1
the common electrode together with the pixel electrode forms an electric field so as to display an image
Implementation Method 2
the liquid crystal layer is changed in accordance with the electric field formed between the pixel electrode and the common electrode
Implementation Method 3
the common electrode senses a capacitance change in accordance with a user's touch
Data Source
AI summary
Disclosed is a display apparatus which facilitates to improve touch sensitivity by decreasing parasitic capacitance between a common electrode and gate/data lines, and decreasing delay on touch sensing and displaying driving, wherein the display apparatus may include a lower panel including a pixel electrode; an upper panel including the common electrode, wherein the common electrode together with the pixel electrode forms an electric field for displaying an image for a displaying driving mode, and the common electrode senses a capacitance change in accordance with a user's touch for a touch sensing mode; and a liquid crystal layer of VA mode formed between the lower and upper panels, and changed in accordance with the electric field between the pixel and common electrodes.