Touch Routing Layout With Planarization for Lower Parasitic Capacitance
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Solution Overview
Problem
The formation of parasitic capacitance between touch routing lines and signal lines for driving displays in touch display devices leads to reduced accuracy and uniformity in touch sensing.
Innovation Solution
Incorporating a touch planarization film between the inclined portion of the encapsulation layer and the touch routing line in the non-active area of the display panel, which reduces parasitic capacitance and allows for adjustment of the touch routing line width, thereby improving touch sensing accuracy and uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If touch routing lines are disposed in the non-active area to connect touch electrodes to touch driving circuits, then touch sensing function is achieved, but parasitic capacitance is formed between touch routing lines and signal lines causing reduced touch sensing accuracy
Solution Approach 1:
The patent introduces a touch planarization film as an intermediary insulating layer between the touch routing lines and the signal lines. This film increases the separation distance and reduces the parasitic capacitance coupling between these conductive elements, thereby resolving the accuracy degradation issue while maintaining the necessary electrical connections for touch sensing functionality.
Solution Approach 2:
The patent addresses the parasitic capacitance issue by utilizing the vertical dimension (thickness direction) rather than only the horizontal plane. By adding a planarization film in the vertical dimension between the routing lines and signal lines, the design achieves effective capacitance reduction without compromising the planar layout and electrical connectivity in the horizontal plane.
2Power
If touch routing line width is increased to reduce resistance and improve signal transmission, then signal transmission quality improves, but parasitic capacitance with signal lines increases causing uniformity degradation in touch sensing
Solution Approach 1:
The touch planarization film serves as a mediator that allows the touch routing lines to have adequate width for signal transmission while preventing excessive parasitic capacitance coupling with signal lines. The film acts as an insulating barrier that decouples the electrical fields, enabling optimized routing line dimensions without compromising sensing uniformity.
3Ease of operation
If encapsulation layer has inclined portion in non-active area to accommodate routing lines, then routing line placement is enabled, but parasitic capacitance with underlying signal lines increases
Solution Approach 1:
The touch planarization film is introduced as an additional intermediary layer between the inclined encapsulation layer and the underlying signal lines. This film compensates for the reduced separation distance created by the inclined encapsulation layer geometry, maintaining effective parasitic capacitance reduction while preserving the routing line placement flexibility provided by the inclined structure.
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 configuration effectively minimizes parasitic capacitance, enhancing the precision and consistency of touch sensing by reducing the load on touch routing lines.
Implementation Method 1
a parasitic capacitance may be formed between the touch routing line and the signal line for driving the display
Data Source
AI summary
A touch display device includes a touch planarization film. The touch planarization film may be disposed on an inclined portion of an encapsulation layer in a non-active area of a display panel, and a touch routing line may be disposed on the planarized area of the touch planarization film, so that it is possible to reduce parasitic capacitance between the touch routing line and a display signal line located under the encapsulation layer without increasing dimensions of the non-active area. Therefore, it is possible to easily adjust a width of the touch routing line and reduce the parasitic capacitance deviation between the touch routing lines, thereby improving the performance of the touch sensing.