Flexible Printed Circuit Pickup for Stringed Instruments
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Solution Overview
Problem
Conventional stringed instrument pickups are large, heavy, difficult to manufacture, and prone to variations in sound due to coil winding issues, with sensitivity to 60 Hz line noise and electromagnetic interference, limiting their suitability for acoustic instruments and requiring complex design modifications.
Innovation Solution
A flexible pickup assembly using a flexible circuit with a plurality of wires and connectors forming a coil, configured to be placed over an existing or new pickup, providing a compact and durable solution that minimizes electromagnetic interference and eliminates the need for extensive coil winding, with optional active pre-amplification circuitry for improved signal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electromagnetic pickups with copper wire coils are used, then string motion can be converted into voltage signal, but the pickup becomes large, heavy, and difficult to manufacture
Solution Approach 1:
The patent replaces the traditional mechanical wire-winding process with a printed circuit board (PCB) technique. Instead of manually or automatically winding thousands of turns of thin copper wire around a bobbin, the coil structure is created by printing conductive traces on a flexible PCB substrate. This substitution eliminates the complex winding machinery and skilled labor requirements while maintaining the electromagnetic induction function.
Solution Approach 2:
The patent changes the physical form and manufacturing parameters of the coil from a three-dimensional wound wire structure to a two-dimensional printed trace structure. The coil resistance, inductance, and physical dimensions are controlled through PCB design parameters such as trace width, trace length, copper thickness, and substrate material properties, rather than through wire gauge and winding turn count.
2Power
If conventional pickups with thousands of wire turns are used, then sufficient signal output is achieved, but manufacturing variations cause sound consistency issues
Solution Approach 1:
The patent replaces the mechanical wire-winding process with a printed circuit board (PCB) technique. Instead of manually or automatically winding thousands of turns of thin copper wire around a bobbin, the coil structure is created by printing conductive traces on a flexible PCB substrate. This substitution eliminates the complex winding machinery and skilled labor requirements while maintaining the electromagnetic induction function.
Solution Approach 2:
The patent changes the physical form and manufacturing parameters of the coil from a three-dimensional wound wire structure to a two-dimensional printed trace structure. The coil resistance, inductance, and physical dimensions are controlled through PCB design parameters such as trace width, trace length, copper thickness, and substrate material properties, rather than through wire gauge and winding turn count.
3Ease of manufacture
If conventional coil winding process is used, then coil is formed, but the process is time-consuming and prone to shorted turns
Solution Approach 1:
The patent replaces the mechanical wire-winding process with a printed circuit board (PCB) technique. Instead of manually or automatically winding thousands of turns of thin copper wire around a bobbin, the coil structure is created by printing conductive traces on a flexible PCB substrate. This substitution eliminates the complex winding machinery and skilled labor requirements while maintaining the electromagnetic induction function.
Solution Approach 2:
The patent performs the coil formation action during the PCB manufacturing process itself, rather than as a separate subsequent step. The conductive traces are printed and cured as part of the standard PCB fabrication sequence, integrating coil creation into the base structure manufacturing. This eliminates the need for separate winding operations and associated quality issues.
4Reliability
If acoustic instruments are used with conventional heavy pickups, then signal can be amplified, but the instrument becomes unbalanced and requires large pockets
Solution Approach 1:
The patent changes the physical form and manufacturing parameters of the coil from a three-dimensional wound wire structure to a two-dimensional printed trace structure. The coil resistance, inductance, and physical dimensions are controlled through PCB design parameters such as trace width, trace length, copper thickness, and substrate material properties, rather than through wire gauge and winding turn count.
Solution Approach 2:
The patent uses a flexible printed circuit board as the substrate for the coil structure. This thin, flexible PCB can be conformally mounted on the instrument body or integrated into the instrument housing, eliminating the need for large recesses or pockets to accommodate a rigid, bulky pickup assembly. The flexible nature allows adaptation to various instrument geometries.
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
The flexible pickup assembly reduces manufacturing complexity, minimizes electromagnetic interference, and provides consistent sound quality, making it suitable for both new and existing instruments, including acoustic ones, while eliminating the need for extensive coil winding and reducing susceptibility to 60 Hz hum.
Implementation Method 1
The electromagnetic field produced by the permanent magnet(s) 15 is normally stationary. However, the vibration of the steel strings disturbs the electromagnetic field and makes it vary. The interaction between the changing electromagnetic field or the changing magnetic flux and the stationary coil induces a time-varying voltage in the coil 12.
Implementation Method 2
A common type being used is an electromagnetic, inductive design. This type of pickup was originally developed in the 1930s and set the pattern for subsequent designs. The most basic type of inductive pickup uses a copper wire coil surrounding one or more permanent magnets.
Data Source
AI summary
A retrofit pickup assembly for stringed instruments is disclosed. The retrofit pickup assembly includes an existing coil and existing or new magnets and a flexible circuit having a plurality of wires and two connectors. A pickup assembly for new stringed instruments is also disclosed utilizing the same principles. A method of retrofitting an existing pickup assembly for stringed instruments is also disclosed.