Integrated Touch Electrode Layout for Precise Multi-Touch 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 complex circuitry, particularly in optical and mutual capacitance types, leading to recognition errors and difficulty in accurately detecting touch spots.
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
1Ease of manufacture
If an add-on type touch sensor is used, then the touch sensor can be manufactured separately and attached, but the display device becomes thick and brightness is reduced
Solution Approach 1:
The patent merges the touch sensor and display device into a single integrated structure where the touch sensor is formed within the display device's substrate layers. This eliminates the need for separate manufacturing and attachment processes, thereby reducing overall thickness while maintaining manufacturing feasibility through integrated fabrication steps.
Solution Approach 2:
The patent creates a multi-functional substrate that simultaneously serves as both the display device substrate and the touch sensor substrate. By forming touch sensor electrodes and display device electrodes on the same substrate, the structure achieves universal functionality, reducing thickness without requiring separate components.
2Length of stationary object
If an on-cell type touch sensor is used, then the touch sensor components are formed on the top glass substrate, but the number of processes and manufacturing costs increase
Solution Approach 1:
The patent combines the formation of touch sensor electrodes and display device electrodes into a single integrated process sequence. By forming both sets of electrodes on the same substrate using similar fabrication steps, the number of separate processes is reduced compared to traditional on-cell type touch sensors that require distinct layers and processes for each function.
3Ease of operation
If an optical type touch sensor is used, then touch can be recognized through light reflection, but touch recognition errors occur under bright surroundings
Solution Approach 1:
The patent replaces the optical reflection-based touch recognition mechanism with an electrostatic capacitance-based mechanism. Instead of detecting light reflection changes, the system detects changes in electrostatic capacitance caused by finger proximity, which is not affected by ambient light conditions, thereby improving reliability under bright surroundings.
4Measurement precision
If a mutual capacitance type touch sensor is used, then touch can be detected through capacitance variation, but parasitic capacitance causes recognition errors
Solution Approach 1:
The patent applies local quality by creating distinct functional zones with different electrode configurations. Touch sensor electrodes are positioned and configured to detect touch input, while display device electrodes are positioned to minimize parasitic capacitance interference. This spatial differentiation allows the system to maintain measurement precision while reducing recognition errors caused 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, and enhances touch recognition precision while minimizing transmittance losses and circuit complexity, allowing for accurate multi-touch detection.
Implementation Method 1
a common electrode COM formed on the second substrate SUB2 in a vertical electric field drive type
Implementation Method 2
an electrostatic capacity type... a variation in mutual capacitance generated on touching can be measured to recognize the touching operation
Data Source
AI summary
A touch display device includes a plurality of pixel electrodes; a plurality of touch electrodes facing the plurality of pixel electrodes, respectively, and 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 is branched into a plurality of first branched signal lines connected to the first touch electrode via a plurality of first contact holes, respectively. The second signal line is branched into a plurality of second branched signal lines connected to the second touch electrode via a plurality of second contact holes, respectively.