Integrated Touch Electrode Layout for Thin, Accurate Displays
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Solution Overview
Problem
Existing touch sensors for display devices face issues such as increased thickness, reduced brightness, higher manufacturing costs, and difficulty in accurately recognizing touch spots due to small mutual capacitance and complex circuitry, particularly in bright environments.
Innovation Solution
A touch sensor integrated display device where touch sensing elements are used as components of the display device, with signal lines overlapping data lines to enhance aperture ratio and durability, and a common electrode with multiple touch electrodes connected to signal lines for precise touch recognition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If add-on type touch sensors are used, then touch sensing function is achieved, but device thickness increases and brightness decreases
Solution Approach 1:
The patent merges the touch sensor functionality with the display device structure by integrating touch electrodes into the common electrode layer of the display. This combination eliminates the need for separate add-on touch sensor layers, thereby reducing overall device thickness while maintaining touch sensing capability.
Solution Approach 2:
The common electrode layer is designed to serve dual functions: as part of the display structure and as the touch sensing electrode. This multi-functionality approach allows the same structural element to provide both display and touch interaction functions, avoiding additional thickness from dedicated touch sensor components.
2Length of stationary object
If on-cell type touch sensors are used, then device thickness is reduced compared to add-on type, but manufacturing complexity and cost increase due to additional electrode layers
Solution Approach 1:
The patent combines touch sensing electrodes with the common electrode layer already required for display operation. By merging these functions into a single layer rather than adding separate touch electrode layers, the patent reduces manufacturing complexity while achieving thin-profile design.
Solution Approach 2:
The common electrode is designed to perform both display function and touch sensing function simultaneously. This multi-functional design eliminates the need for separate driving and sensing electrode layers, thereby simplifying the manufacturing process while maintaining reduced device thickness.
3Length of stationary object
If optical type touch sensors are used, then device thickness is reduced, but touch recognition accuracy deteriorates in bright environments
Solution Approach 1:
The patent replaces the optical sensing mechanism with an electrostatic capacitance sensing mechanism. By using capacitive touch electrodes integrated into the common electrode layer, the system achieves thin-profile design while maintaining accurate touch detection through electrical field sensing rather than optical reflection, thereby overcoming brightness-related accuracy issues.
4Reliability
If mutual capacitance type touch sensors are used, then touch sensing is achieved, but touch spot recognition accuracy is poor due to small mutual capacitance and parasitic capacitance
Solution Approach 1:
The patent changes the sensing mechanism from measuring small mutual capacitance variations to measuring self-capacitance changes at each touch electrode. By using self-capacitance sensing with electrodes integrated into the common electrode layer, the system achieves improved touch spot recognition accuracy by detecting larger capacitance changes directly at the touch location rather than relying on small mutual capacitance variations affected by parasitic capacitance.
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 reduces device thickness, improves durability, enhances touch recognition accuracy, and simplifies circuitry while maintaining high aperture ratio and reducing transmittance losses.
Implementation Method 1
the touch electrodes may be used to recognize a touch operation in a mutual capacitance manner or in a self capacitance manner
Implementation Method 2
An object touching the optical sensing layer can be recognized through light reflected on the object by using light from a back light unit or infrared ray light
Data Source
AI summary
A touch display device includes a plurality of pixel electrodes; a plurality of touch electrodes configured to face the plurality of pixel electrodes, respectively, the plurality of touch electrodes including at least a first touch electrode and a second touch electrode separated from each other; a first signal line connected to the first touch electrode, the first signal line overlapping the second touch electrode without being connected to the second touch electrode; and a second signal line connected to the second touch electrode, the second signal line overlapping the first touch electrode without being connected to the first touch electrode. The first signal line and the second signal line may be configured to apply touch drive signals respectively to the first touch electrode and the second electrode during a touch driving mode.