Printed Circuit Angled Wire Design for Touch Panel Yield
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Solution Overview
Problem
The screen printing technique for printed circuits, particularly in touch panels, faces significant yield reduction due to silver colloid spilling over edges, causing short circuits as line widths and spacings become smaller, leading to manufacturing inefficiencies.
Innovation Solution
The design features a printed circuit with conductive wires having specific angled connections and spacings that prevent silver colloid overflow during the screen printing process, ensuring electrical independence and reducing the likelihood of short circuits by maintaining adequate distance between adjacent wires.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If screen printing technique is used with smaller line widths and spaces, then printing speed and cost are improved, but silver colloid spills over edges causing short circuits and reducing manufacturing yield
Solution Approach 1:
The patent applies curved transitions instead of sharp right angles at the corners of conductive wires. The screen design includes rounded corners with specific curvature radii that prevent silver colloid from spilling over during printing. This curvature modification allows smaller line widths and spaces to be printed without causing short circuits between adjacent wires, thus maintaining high productivity while improving manufacturing yield.
2Device complexity
If line width and space between adjacent lines are reduced, then circuit density is improved, but silver colloid spilling causes short circuits
Solution Approach 1:
The patent modifies the corner geometry of conductive wires by introducing curved transitions with specific curvature radii. This curvature design creates a gradual transition zone that prevents silver colloid from spilling over during screen printing, even when line widths and spaces are reduced to increase circuit density. The rounded corners maintain adequate spacing between adjacent wires while allowing higher circuit density.
Solution Approach 2:
The patent specifies precise parameter values for the curvature radius of rounded corners and the spacing between adjacent conductive wires. By optimizing these parameters, the design achieves high circuit density while preventing silver colloid spilling. The curvature radius is carefully selected to be large enough to prevent spilling but small enough to maintain compact circuit design.
3Ease of manufacture
If right angles or rounded corners are used in screen design, then manufacturing process is simplified, but silver colloid spills over edges reducing yield
Solution Approach 1:
The patent adopts rounded corners with specific curvature radii in the screen design, which is a modification of the traditional right angle design. This curved corner design maintains ease of manufacture by using standard screen printing techniques while effectively preventing silver colloid from spilling over edges. The rounded corners are implemented through straightforward geometric modifications that do not significantly complicate the manufacturing process.
Data Source
AI summary
A printed circuit includes a number of conductive wires. Each of the conductive wires includes a first conductive wire section, a second conductive wire section, and a first connection section. The first connection section includes a first end and a second end opposite to the first end, the first end of the first connection section is connected to the first conductive wire section, and the second end of the first connection section is connected to the second conductive wire section. An angle between the first conductive wire section and the first connection section can be in a range from about 90 degrees to about 180 degrees.