Laser-Ablated Thin Film Circuits for Planar Magnetic Transducers
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Solution Overview
Problem
Existing methods for manufacturing thin film circuits for acoustic transducers, such as chemical etching, face issues like mechanical and thermal failures, large impedance variations, low precision, environmental pollution, and inefficiencies, which affect the performance and reliability of planar magnetic transducers.
Innovation Solution
The use of laser ablation or delamination to create conductive circuits on a diaphragm substrate by selectively removing conductive material, allowing for precise control of trace dimensions to match the magnetic flux density and optimize performance characteristics, such as uniform force distribution and reduced impedance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If chemical etching is used to create conductive circuits, then the manufacturing process is simple, but the precision of trace dimensions is poor and environmental pollution occurs
Solution Approach 1:
The patent replaces chemical etching with laser ablation to create conductive circuits. The laser beam precisely removes conductive material layer by layer through controlled ablation, achieving superior trace dimension precision (widths down to 10 microns) without the environmental pollution and precision limitations of chemical etching processes.
Solution Approach 2:
The patent changes the manufacturing parameter from chemical reaction-based etching to laser energy-based ablation. By controlling laser power, pulse duration, and scanning speed, the process achieves precise dimensional control of conductive traces while maintaining manufacturing feasibility through automated processing.
2Reliability
If conventional chemical etching is used, then production cost is low, but environmental pollution and reliability issues occur
Solution Approach 1:
The patent replaces chemical etching with laser ablation, eliminating the need for corrosive chemicals and their associated environmental pollution. The laser process creates clean, precise conductive circuits with superior reliability by directly ablatting material without chemical contamination or mechanical stress that could cause trace failures.
3Power
If trace width is increased to reduce impedance, then current carrying capacity improves, but force distribution uniformity deteriorates
Solution Approach 1:
The patent applies local quality by varying trace dimensions across different regions of the diaphragm. Traces are made narrower in high magnetic flux density areas and wider in low flux density areas, optimizing both current distribution and force uniformity. This localized dimension control allows the circuit to achieve excellent force distribution while maintaining adequate current carrying capacity through strategic dimensional variation.
4Manufacturing precision
If laser ablation is used to create fine traces, then manufacturing precision improves, but device complexity increases
Solution Approach 1:
The patent replaces complex chemical etching processes with laser ablation, which achieves superior precision (10 micron trace widths) through direct material removal. While laser equipment is sophisticated, the process eliminates multiple chemical handling steps, masking operations, and environmental control systems, potentially simplifying the overall manufacturing workflow despite the advanced laser technology required.
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 enables the creation of thin film circuits with finer trace widths and spacings, increasing efficiency and power density, allowing for uniform force distribution, higher output, and the ability to drive transducers with vacuum tubes, while reducing environmental impact and production costs.
Implementation Method 1
a laser is used to remove conductive material from the conductive layer to create the conductive circuit
Implementation Method 2
The diaphragm in a planar magnetic transducer includes a conductive circuit pattern that, when energized, creates forces that move the diaphragm in the magnetic field to produce sound
Data Source
Figure 1
Figure 2
AI summary
A conductive circuit of a thin film for using in a planar magnetic transducer, where the conductive circuit is created from laser etching, including laser ablation or laser delamination of portions of a conductive material disposed on a diaphragm substrate. The conductive circuit so formed has varied widths, height, or spacing throughout the diaphragm, allowing for adaptation to certain desired performance characteristics. Performance characteristics include a uniform force distribution on the diaphragm, creating very high impedance circuits, increasing current in the circuit, increasing force, and increasing efficiency.