In-Cell Touch Panel Line Length Asymmetry for Capacitance Matching
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Solution Overview
Problem
In in-cell type display devices with integrated touch panels, the increasing distance between electrodes and lines leads to parasitic capacitance deviations, reducing touch sensing accuracy and reliability due to the differential self sensing unit's sensitivity to changes in capacitance.
Innovation Solution
The display device incorporates a touch panel with electrode columns and lines where the lengths of lines in adjacent columns are strategically varied to minimize parasitic capacitance differences, using a symmetrical disposition of contact holes and lines to ensure accurate touch sensing by comparing electrodes with similar parasitic capacitances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the distance from the display drive IC to the electrodes is increased, then the overlapping area of electrodes and lines increases, but the parasitic capacitance of the electrodes increases, causing reduction in touch sensing accuracy and reliability
Solution Approach 1:
The patent applies asymmetry by configuring the lines to have different lengths in different electrode columns. Specifically, lines in the first electrode column have lengths that increase from one end, while lines in the second electrode column have lengths that decrease from the same end. This asymmetric length configuration compensates for the varying overlapping areas between electrodes and lines at different distances from the display drive IC, thereby maintaining consistent parasitic capacitance values across all electrodes and improving touch sensing accuracy.
2Area of stationary object
If the distance from the display drive IC to the electrodes is increased, then the overlapping area of electrodes and lines increases, but the parasitic capacitance of the electrodes increases, causing reduction in touch sensing reliability
Solution Approach 1:
The patent applies asymmetry by configuring the lines to have different lengths in different electrode columns. Specifically, lines in the first electrode column have lengths that increase from one end, while lines in the second electrode column have lengths that decrease from the same end. This asymmetric length configuration compensates for the varying overlapping areas between electrodes and lines at different distances from the display drive IC, thereby maintaining consistent parasitic capacitance values across all electrodes and improving touch sensing accuracy.
3Device complexity
If the line lengths are made equal in all electrode columns, then the structure is simplified, but the parasitic capacitance varies significantly across different electrodes, reducing touch sensing performance
Solution Approach 1:
The patent applies local quality by making the line lengths different for different electrode columns based on their specific positions and overlapping areas. Instead of using uniform line lengths throughout, the patent configures lines in the first electrode column with increasing lengths and lines in the second electrode column with decreasing lengths, tailored to each column's specific geometric relationship with the display drive IC. This localized differentiation ensures that each electrode has consistent parasitic capacitance, thereby maintaining high touch sensing accuracy.
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 enhances touch sensing accuracy and reliability by minimizing error data from parasitic capacitance variations, allowing for precise touch detection even with electrodes at varying distances from the display drive IC, thereby improving overall touch sensing performance.
Implementation Method 1
a parasitic capacitance is generated between the plurality of electrodes 11 and the plurality of lines
Implementation Method 2
an in-cell self-capacitive type display device including an integrated touch panel
Implementation Method 3
a touch IC (not shown) that receives a plurality of touch sense signals, which are generated based on a touch scan signal from the plurality of electrodes
Data Source
AI summary
A display device comprises a touch panel including a plurality of electrode columns that each includes a plurality of electrodes positioned in the electrode column. The display device further comprises a plurality of lines, each of which is connected to a corresponding electrode included in a corresponding one of the plurality of electrode columns. The lengths of the lines within a first electrode column increase as the lines are positioned further from one end of the first electrode column that is not adjacent to the second electrode column in a direction substantially perpendicular to a longitudinal direction of the lines of the first electrode column and the lengths of the lines within a second electrode column decrease as the lines are positioned further from the one end of the first electrode column in the direction substantially perpendicular to a longitudinal direction of the lines of the second electrode column.