Double-Layer PCB Touchpad Eliminates Carbon Film Wear
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Solution Overview
Problem
The existing double-layer printed circuit board touchpads face manufacturing complexity and high costs due to the use of carbon film wires, which wear out over time, reducing the touchpad's stability and lifespan.
Innovation Solution
A touchpad design with a double-layer printed circuit board structure featuring serially-connected conductive units and conductive wires that directly connect to a component zone, eliminating the need for carbon film wires and using through-hole, wire, cylindrical, or hexahedral conductors to form touch-sensitive lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If carbon film wire is used to connect Y-axis touch-sensitive lines, then the touchpad can be manufactured with existing processes, but the manufacturing procedure becomes complicated and the manufacturing cost increases
Solution Approach 1:
The patent extracts and eliminates the carbon film wire from the touchpad structure. Instead of using carbon film wire to connect Y-axis touch-sensitive lines, the invention uses direct conductive traces on the printed circuit board, removing the unnecessary intermediate component and simplifying the overall structure.
Solution Approach 2:
The patent merges the function of carbon film wire connection into the printed circuit board trace system. The X-axis and Y-axis touch-sensitive lines are directly integrated onto the PCB layers, combining multiple functions (connection, conduction, structural support) into a unified PCB structure rather than using separate carbon film wire components.
2Ease of manufacture
If carbon film wire is used to connect Y-axis touch-sensitive lines, then the touchpad can be assembled, but the manufacturing cost becomes high
Solution Approach 1:
The patent replaces the expensive carbon film wire with standard PCB trace materials that are already part of the printed circuit board manufacturing process. This substitution uses readily available, cost-effective materials and processes that are standard in PCB fabrication, eliminating the need for additional expensive materials.
Solution Approach 2:
The PCB trace system serves multiple functions simultaneously: it provides structural support, electrical connection, and signal conduction. This multi-functional integration eliminates the need for separate carbon film wire components, reducing material costs and simplifying the bill of materials.
3Ease of manufacture
If carbon film wire is used for connection, then the touchpad can be manufactured, but the carbon film wire wears out during usage which decreases the touchpad lifespan
Solution Approach 1:
The patent extracts and removes the wear-prone carbon film wire from the structure. By eliminating this consumable component, the invention prevents the wear-out mechanism that limited the touchpad's operational life, resulting in a more reliable and durable product.
Solution Approach 2:
The patent changes the material parameter from carbon film (which wears) to metal traces on PCB (which are durable). This parameter change in material composition and structural form factor transforms a wear-prone system into a robust, long-lasting connection system that maintains electrical properties over time.
4Ease of manufacture
If carbon film wire is used to connect Y-axis lines, then the touchpad can function, but the electric characters of carbon film wear out which influences the stability
Solution Approach 1:
The patent replaces the electrically unstable carbon film with stable metal PCB traces that maintain consistent electrical characteristics. This substitution eliminates the degradation of electrical properties over time, ensuring stable touchpad performance throughout its operational life.
Solution Approach 2:
The patent uses composite PCB structure with copper traces on fiberglass substrate, providing both mechanical strength and stable electrical conductivity. This composite material approach offers superior electrical stability compared to carbon film, with consistent resistance and conductive properties that do not degrade with use.
Data Source
AI summary
The present invention provides a touchpad with a double-layer printed circuit board structure. The touchpad comprises an upper layer, a bottom layer, a first conductor; and a second conductor; wherein the upper layer is configured to act as a touch-sensitive zone, and comprises a plurality of first conductive units, a first conductive wire and a plurality of second conductive units; the bottom layer comprises a wire connecting zone and a component zone, wherein the wire connecting zone further includes a second conductive wire and a connecting line configured to be electrically coupled to the component zone; and the first conductor and the second conductor are configured to connect the upper layer to the bottom layer; wherein the first and the second conductive units are each serially-connected to form a first touch-sensitive line and a second touch-sensitive line, respectively.