Touch Sensor Routing Openings Reduce Gate Line Coupling
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Solution Overview
Problem
Incorporating touch sensors into displays can compromise either the touch sensor or display functionality if not properly integrated, leading to challenges in capacitive coupling between signal routing paths and gate lines.
Innovation Solution
The use of patterned metal layers and transparent conductive materials like indium tin oxide to form capacitive touch sensor electrodes, with strategically placed openings in the touch sensor signal border routing paths that overlap gate lines to reduce capacitive coupling, allowing for effective integration of touch sensors within the display without interfering with the display's operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If touch sensor circuitry is integrated into the display active area, then touch sensor functionality is achieved, but capacitive coupling between gate lines and signal routing paths increases causing interference
Solution Approach 1:
The patent segments the display into active area and inactive border area, placing touch sensor circuitry specifically in the inactive border area rather than the active area. This spatial segmentation allows touch sensor electrodes to be formed in regions where they do not interfere with pixel operations, reducing capacitive coupling between gate lines and signal routing paths while maintaining both functionalities.
Solution Approach 2:
The patent introduces an intermediary approach by forming touch sensor electrodes in the inactive border area, which acts as a buffer zone between the touch sensor circuitry and the active pixel area. This intermediary placement reduces direct capacitive coupling and interference between the gate lines and signal routing paths while still enabling touch sensor functionality.
2Adaptability or versatility
If touch sensor electrodes are formed in the active area, then touch sensing is enabled, but display functionality is compromised due to interference
Solution Approach 1:
The patent divides the display into distinct functional zones: the active area for pixel operations and the inactive border area for touch sensor circuitry. By segmenting these functions spatially, the patent enables touch sensing without compromising display reliability, as the gate lines and signal routing paths in the active area remain electrically isolated from the touch sensor electrodes in the border area.
3Productivity
If signal routing paths are placed near gate lines, then routing efficiency is improved, but capacitive coupling increases causing signal interference
Solution Approach 1:
The patent extracts the touch sensor signal routing paths from proximity to the gate lines by placing them in the inactive border area. This extraction removes the harmful capacitive coupling between the signal routing paths and gate lines, preventing signal interference while maintaining routing efficiency through the border area's dedicated pathways.
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 enables the integration of touch sensors into displays while minimizing capacitive coupling, thereby maintaining the integrity of both touch sensor and display functionalities, enhancing signal-to-noise ratios and overall performance.
Implementation Method 1
capacitive touch sensor electrodes formed in the active area from the first indium tin oxide layer
Implementation Method 2
Liquid crystal material may be interposed between the electrode fingers of each pixel and the common voltage electrode
Data Source
AI summary
A display may have an array of pixels. A transparent conductive layer may serve as a common voltage electrode layer and may distribute a common voltage to each of the pixels. Metal layers may be used to form routing structures. One of the metal layers may be patterned to form gate lines that distribute control signals to thin-film transistors in the pixels. Touch sensor circuitry may be coupled to horizontal and vertical capacitive touch sensor electrodes formed from the transparent conductive layer. A touch sensor signal border routing path in an inactive area of the display may have openings that run parallel to the gate lines and that each overlap one of the gate lines to reduce capacitive coupling between the gate lines and the touch sensor signal border routing path.