Touch Panel Wiring Area Trimming for Capacitance Control
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Solution Overview
Problem
The existing methods for forming a wiring area in touch panels using laser trimming result in a tolerance margin that is wider than other wirings, leading to capacity-coupling with nearby wirings or the sensor part, affecting the electrical properties and causing erroneous performance when touched by a finger.
Innovation Solution
The solution involves forming a wiring area with first and second trimming lines over a conductive area, where the first section has a narrower width and the second section has a wider width than the first, with the second trimming line crossing the first to adjust the wiring width and reduce coupling capacitance, thereby stabilizing electrical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a tolerance margin is formed wider than other wirings by a conductive material in consideration of errors, then the tolerance for laser trimming position errors is improved, but the electrical properties of the touch panel are worsened due to capacity-coupling with nearby wiring or sensor part
Solution Approach 1:
The conductive area is divided into multiple independent conductive regions by cutting with trimming lines. These segmented conductive areas are electrically isolated from each other, preventing capacity-coupling between adjacent conductive regions while maintaining the tolerance margin function for laser trimming position errors.
Solution Approach 2:
The harmful capacity-coupling effect is extracted and eliminated by strategically placing cutting trimming lines between conductive areas. The trimming lines remove the conductive material that would otherwise create unwanted capacitive coupling, separating the tolerance margin function from the harmful electrical interaction.
2Adaptability or versatility
If the conductive area is made wider to provide tolerance margin, then the allowance for trimming position error is improved, but the coupling capacitance with nearby wiring increases causing erroneous performance
Solution Approach 1:
The wide conductive area is segmented into multiple smaller conductive regions by cutting trimming lines. This segmentation reduces the overall coupling capacitance between adjacent conductive areas while preserving the tolerance margin width for accommodating laser trimming position errors.
Solution Approach 2:
The trimming lines act as intermediary non-conductive elements between adjacent conductive areas. These intermediaries electrically isolate the conductive regions, preventing direct capacitive coupling while allowing the conductive areas to maintain their width for tolerance margin purposes.
3Manufacturing precision
If laser trimming is used to form wiring area, then the wiring can be precisely formed, but a tolerance margin must be provided outside the wiring area which causes capacity-coupling problems
Solution Approach 1:
The wiring area structure is segmented by introducing cutting trimming lines that divide the conductive area into multiple isolated regions. This segmentation resolves the capacity-coupling problem inherent in traditional laser trimming approaches by electrically isolating adjacent conductive regions while maintaining precise wiring formation.
Solution Approach 2:
The cutting trimming lines are preliminarily planned and positioned to prevent capacity-coupling issues before they occur. By pre-determining the locations of these cutting lines during the design stage, the patent prevents harmful electrical interactions while maintaining the precision benefits of laser trimming.
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 approach reduces the influence of the conductive area on nearby wirings, balances wiring resistance, and stabilizes the electrical properties of the touch panel, preventing erroneous operations.
Implementation Method 1
a first and a second trimming lines L1, L2 are provided over a conductive area 5 located inside and/or outside of several wirings in the wiring area 2
Data Source
AI summary
Possibility of erroneous operation caused by a conductive area as a tolerance margin is reduced and electrical properties are prevented from becoming poor.A touch panel includes: a sensor part; and a wiring area including a wiring for connecting the sensor part and a connector part, in which a first and a second trimming lines are provided over a conductive area located inside and/or outside of several wirings in the wiring area, a first section including a wiring with a first width and a second section including a wiring with a second width crossing the conductive area in the width direction and wider than the first width are formed by the first trimming line, and the second trimming line crosses the first trimming line in the second section so that the width of the wiring in the second section is narrower than the second width