In-cell Touch Display with Segmented Common Electrodes
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Solution Overview
Problem
In-cell touch display panels face limitations in resolution and size due to the complexity of integrating touch and display functions, leading to reduced display quality and increased material costs, with existing solutions struggling to manage capacitance and signal interference between touch and display circuits.
Innovation Solution
A high-sensitivity in-cell touch display device is designed with a touch-dedicated independent power supply and common voltage and sensing electrodes that operate as a common node for both touch and display circuits, minimizing current loops and using reflective deflection electrodes to reduce parasitic capacitance, allowing parallel operation of touch and display functions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a separate touch panel is mounted on a display panel, then touch sensing function is achieved, but the structure becomes complicated and material cost increases
Solution Approach 1:
The patent combines the touch sensing function and display function into a single integrated device. The touch panel and display panel are merged into one structure, eliminating the need for separate mounting processes and reducing material costs while maintaining both functionalities.
Solution Approach 2:
The common electrode layer serves dual purposes: it functions as both the common electrode for touch sensing operations and as part of the display structure. This multi-functionality reduces the number of separate components needed and simplifies the overall device structure.
2Adaptability or versatility
If a separate touch panel is mounted on a display panel, then touch sensing function is achieved, but light penetration rate decreases and display quality degrades
Solution Approach 1:
By merging the touch panel and display panel into a single integrated structure, the patent eliminates the additional layers and interfaces that would otherwise reduce light penetration. The integrated design allows light to pass through more efficiently while still providing touch sensing capability.
3Reliability
If time sharing is applied for touch sensing in display silent interval, then capacitance between common electrode and sensing electrodes is managed, but resolution increase makes display operation insufficient time for touch sensing
Solution Approach 1:
The patent divides the common electrode layer into multiple segmented electrodes that can be independently controlled. This segmentation allows different regions to be used for touch sensing while other regions maintain display operations simultaneously, enabling parallel processing and eliminating the time-sharing limitation.
Solution Approach 2:
By using segmented common electrodes, the patent enables continuous touch sensing operations without interrupting display operations. Multiple sensing regions can operate continuously in parallel with display regions, eliminating the need to wait for display silent intervals and thereby increasing productivity.
4Area of stationary object
If screen size is enlarged, then display area increases, but number of touch points increases requiring more scanning time
Solution Approach 1:
The common electrode layer is segmented into multiple independently controllable electrodes distributed across the enlarged screen area. This segmentation allows parallel scanning of multiple touch points simultaneously, reducing the total scanning time required even as the screen size and number of touch points increase.
Solution Approach 2:
The patent transitions from sequential scanning in one dimension to parallel scanning across multiple dimensions by using segmented electrodes that can be activated simultaneously in different regions, effectively adding a spatial dimension to the scanning process and reducing time loss.
5Reliability
If common electrode is divided into multiple electrodes operated as touch electrodes, then capacitance between common electrode and sensing electrodes is reduced, but current loop between touch circuit and display circuit causes voltage interference
Solution Approach 1:
The patent extracts the power supply function for the touch circuit from the display circuit by introducing an independent power supply. This separation removes the source of current loop interference, allowing the segmented common electrodes to reduce capacitance without causing voltage interference between touch and display operations.
6Adaptability or versatility
If in-cell touch display panels are used, then integration of touch and display functions is achieved, but resolution and screen size are limited
Solution Approach 1:
The segmented common electrode structure enables high-resolution touch sensing across large screen areas by allowing parallel operation of multiple sensing regions. This segmentation removes the limitation on resolution and screen size that plagues conventional in-cell touch displays while maintaining full function integration.
Data Source
AI summary
A high-sensitivity in-cell touch display device has a common voltage and sensing electrode layer including a plurality of common voltage and sensing electrodes, each corresponding to at least one pixel electrode. A touch circuit is provided with a touch-dedicated power supply circuit, and a common voltage and sensing electrode is used as a common node of the touch circuit and a display circuit, so that there is no current loop between the touch circuit and the display circuit. Reflection electrodes are further provided to reduce parasitic capacitance between the common voltage and sensing electrodes and to improve the sensing distance. The display operation and the touch sensing operation can be performed on different areas in parallel to increase respective efficiencies of the display and touch sensing operations.