Touch Panel Detecting Electrode Overhangs for Unequal Drive Widths
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Solution Overview
Problem
In display devices with integrated touch panels, differences in driving electrode widths lead to unequal electrostatic capacitance between driving and detecting electrodes, resulting in reduced noise immunity and capacitance tolerance, especially when the number of pixels is not evenly divisible, affecting input position detection accuracy.
Innovation Solution
The input device employs a configuration where the detecting electrodes have expanding portions to adjust overlapping areas with driving electrodes of varying widths, ensuring equal electrostatic capacitance and maintaining noise immunity by adjusting the area of intersection portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the number of pixels is not evenly divisible by the number of driving electrodes, then the driving electrode widths must be different to cover all pixels, but this causes unequal electrostatic capacitance between driving and detecting electrodes, reducing noise immunity and detection accuracy
Solution Approach 1:
The detecting electrode is designed with a variable width configuration where the width varies in different regions to match the driving electrode widths. Specifically, the detecting electrode has a first width in a first region and a second width in a second region, allowing each region to have locally optimized capacitance characteristics that compensate for the non-uniform driving electrode widths, thereby maintaining equal electrostatic capacitance across all driving-detecting electrode pairs despite the non-evenly-divisible pixel configuration
Solution Approach 2:
The patent changes the geometric parameters (widths) of the detecting electrode to adjust the overlapping areas with driving electrodes of different widths. By modifying the width parameter of the detecting electrode in different regions, the electrostatic capacitance is balanced across all electrode pairs, resolving the contradiction between adaptability to non-uniform configurations and maintaining reliable detection performance
2Ease of manufacture
If the detecting electrode width is uniform, then the manufacturing is simpler, but the electrostatic capacitance becomes unequal when driving electrode widths vary, affecting input position detection accuracy
Solution Approach 1:
Instead of using a uniform detecting electrode width throughout, the patent applies local quality by varying the width of the detecting electrode in different regions. The detecting electrode has different widths (first width and second width) corresponding to different driving electrode widths, ensuring that each local region achieves equal electrostatic capacitance. This localized adjustment maintains detection precision while accommodating variations in driving electrode geometry
3Device complexity
If the detecting electrode overlapping area with varying width driving electrodes is not adjusted, then the electrode configuration is simpler, but the electrostatic capacitance becomes unequal, reducing capacitance tolerance and noise immunity
Solution Approach 1:
The patent changes the width parameter of the detecting electrode to adjust the overlapping areas with driving electrodes of different widths. By modifying this geometric parameter, the electrostatic capacitance is equalized across all driving-detecting electrode pairs, ensuring consistent capacitance tolerance and noise immunity throughout the touch panel despite the varying driving electrode widths required for non-evenly-divisible pixel configurations
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 maintains consistent electrostatic capacitance and noise immunity across electrodes of different widths, enhancing input position detection accuracy and reliability in display devices with integrated touch panels.
Implementation Method 1
a plurality of capacitive elements composed of a pair of electrodes disposed to face each other via a dielectric layer, namely, a driving electrode and a detecting electrode
Implementation Method 2
an input position is detected based upon a first electrostatic capacitance between the third electrode and the first electrode and a second electrostatic capacitance between the third electrode and the second electrode
Data Source
AI summary
A noise immunity of a detected capacitance is prevented or inhibited from lowering on a driving electrode different in width from the other driving electrodes, provided in an input device. A touch panel serving as an input device has a plurality of driving electrodes extending in an X-axis direction and arranged in a Y-axis direction intersecting with the X-axis direction, and a driving electrode arranged outside one side of an arrangement of the driving electrodes and extending in the X-axis direction. Further, the touch panel TP1 has a plurality of detecting electrodes extending in the Y-axis direction and arranged in the X-axis direction. The width of the driving electrode is smaller than the widths of the driving electrodes and the detecting electrode includes an expanding portion for expanding the area of the detecting electrode on the side opposite to the plurality of driving electrodes via the driving electrode.