Touch Sensor Integrated FFS Display Device Thickness Reduction
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Solution Overview
Problem
Existing touch sensor technologies for display devices face challenges in reducing device thickness and simplifying manufacturing processes, while also improving touch sensitivity, as both add-on and on-cell types have limitations such as increased thickness, reduced brightness, and increased manufacturing costs.
Innovation Solution
A touch sensor integrated type display device that shares touch sensing elements with the display device, utilizing common electrodes as both touch driving and sensing electrodes, with resistance reducing wires to minimize electrode resistance and increase mutual capacitance, thereby reducing device thickness and simplifying manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an add-on type touch sensor is mounted on the display device, then the touch sensing function is achieved, but the thickness of the display device increases
Solution Approach 1:
The patent merges the touch sensor structure with the display device structure by forming touch driving electrodes and touch sensing electrodes within the same glass substrate that contains the pixel electrodes and common electrodes. This integration eliminates the need for a separate add-on touch sensor layer, thereby achieving touch sensing functionality while avoiding the thickness increase that would result from mounting a separate touch sensor on top of the display device.
Solution Approach 2:
The patent makes the common electrode serve dual functions: as the common electrode for liquid crystal display operation and as the touch driving electrode for touch sensing. This multi-functionality reduces the number of separate electrode layers needed, contributing to reduced overall thickness while maintaining both display and touch sensing capabilities.
2Length of stationary object
If an on-cell type touch sensor is formed on the glass substrate, then the thickness is reduced compared to add-on type, but the entire thickness increases due to touch driving electrode layer, touch sensing electrode layer, and insulating layer
Solution Approach 1:
The patent makes the common electrode serve dual functions: as the common electrode for liquid crystal display operation and as the touch driving electrode for touch sensing. This multi-functionality eliminates the need for a separate touch driving electrode layer, reducing the total number of layers while maintaining both display and touch sensing capabilities.
Solution Approach 2:
The patent merges the touch sensor structure with the display device structure by forming touch driving electrodes and touch sensing electrodes within the same glass substrate that contains the pixel electrodes and common electrodes. This integration eliminates the need for separate insulating layers that would be required between distinct touch and display electrode structures, thereby reducing overall thickness and layer complexity.
3Length of stationary object
If an on-cell type touch sensor is formed on the glass substrate, then the thickness is reduced, but the manufacturing cost and number of processes increase
Solution Approach 1:
The patent merges the touch sensor structure with the display device structure by forming touch driving electrodes and touch sensing electrodes within the same glass substrate that contains the pixel electrodes and common electrodes. This integration allows both display and touch sensing components to be manufactured simultaneously using the same deposition and patterning processes, eliminating the need for separate manufacturing steps for touch sensor fabrication and reducing overall manufacturing cost.
Solution Approach 2:
The patent makes the common electrode serve dual functions: as the common electrode for liquid crystal display operation and as the touch driving electrode for touch sensing. This multi-functionality reduces the number of separate electrode fabrication processes needed, as the same electrode structure serves both purposes, thereby simplifying the manufacturing process and reducing costs.
4Ease of manufacture
If the common electrode is used as touch driving electrode, then the manufacturing process is simplified, but the electrode resistance increases
Solution Approach 1:
The patent introduces a resistance reducing wire as an intermediary conductive element that is electrically connected to the common electrode (which serves as the touch driving electrode). This resistance reducing wire compensates for the inherent high resistance of the common electrode material by providing an additional low-resistance conduction path, thereby maintaining the manufacturing simplicity of using the common electrode while correcting the resistance issue.
5Reliability
If the touch sensing electrode is formed between pixel electrodes, then the touch sensitivity is improved, but the aperture ratio is reduced
Solution Approach 1:
The patent forms the touch sensing electrode to overlap with the common electrode only in specific regions where touch sensing is required, rather than uniformly across the entire display area. This localized approach allows touch sensitivity to be enhanced in critical areas while minimizing the impact on the overall aperture ratio, as the touch sensing electrode does not occupy additional space in regions where it is not needed for touch detection.
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
The solution effectively reduces the thickness of the display device, simplifies the manufacturing process, and enhances touch sensitivity by increasing mutual capacitance between touch driving and sensing electrodes, allowing for adjustable touch recognition blocks and improved user interaction.
Implementation Method 1
one of the first and second electrodes serves as a common electrode for driving the display device... a liquid crystal layer... positioned between the first substrate and the second substrate... pixel electrodes... positioned in the pixel areas... common electrode... positioned to be opposite to the plurality of pixel electrodes
Implementation Method 2
common electrode... operable to sense touch... first and second electrodes... facing each other with the pixel electrode and the liquid crystal layer therebetween
Data Source
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AI summary
The invention concerns a touch sensor integrated type display device. The display device is a fringe field switching (FFS) liquid crystal display and includes a plurality of gate lines, a plurality of data lines crossing over the plurality of the gate lines, a plurality of pixel electrodes formed in areas defined by crossing over the gate lines and the data lines, a plurality of first electrodes formed between pixel electrodes which are neighbored to each other with a gate line therebetween, a plurality of second electrodes, each of the second electrodes formed to overlap with at least one portion of the pixel electrode and arranged in parallel with the gate line, wherein one of the first and second electrodes serve as common electrodes for driving the display device.