Multilayer Coil Structure With Fe Gradient for Higher Impedance
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Solution Overview
Problem
Existing multilayer coil components have limitations in increasing impedance, as disclosed in Japanese Unexamined Patent Application Publication No. 2004-207608, which seeks to enhance impedance but falls short in achieving significant improvements.
Innovation Solution
A multilayer coil component with a multilayer body comprising insulating layers and coil conductors, where the insulating layers have distinct Fe content regions, with a higher average Fe content between adjacent coil conductors and a lower average Fe content inside the coil, and a method of manufacturing this component by laminating green sheets with magnetic and non-magnetic materials, ensuring a difference in shrinkage percentages between the electrically conductive paste and the green sheets during firing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the insulating layers have uniform Fe content throughout, then the manufacturing process is simple, but the impedance cannot be sufficiently increased
Solution Approach 1:
The insulating layers are designed with non-uniform Fe content distribution, where the first region (between adjacent coil conductors) has higher Fe content than the second region (inside the coil). This local quality variation creates different magnetic permeability in different areas, which increases the overall impedance without requiring complete structural redesign
Solution Approach 2:
The Fe content parameter in the insulating layers is changed spatially to achieve different magnetic properties. By controlling the Fe content to differ by at least 1.7% weight between the first and second regions, the magnetic permeability is optimized to increase impedance while maintaining manufacturing feasibility through controlled composition gradients
2Manufacturing precision
If the shrinkage percentages of electrically conductive paste and green sheets are similar, then the firing process is easier to control, but the Fe content distribution in the insulating layers cannot be sufficiently differentiated
Solution Approach 1:
The shrinkage percentage parameter of the electrically conductive paste is specifically adjusted to differ from that of the green sheets by at least 1.2%. This parameter change ensures that during firing, the paste and green sheets shrink at different rates, creating the necessary Fe content differentiation in the insulating layers while maintaining controllable firing conditions through established shrinkage ratios
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 approach effectively increases impedance by creating regions with varying magnetic permeability, enhancing the multilayer coil component's performance by achieving a difference in average Fe content between the regions, thereby improving impedance values.
Implementation Method 1
the insulating layers have a magnetic phase and a non-magnetic phase
Implementation Method 2
The firing includes pushing out the non-magnetic material from a first region that is located between the coil conductors adjacent to each other in the lamination direction toward a second region that is a region inside the coil excluding the first region. An absolute value of a shrinkage percentage of the electrically conductive paste during firing is smaller than an absolute value of a shrinkage percentage of each of the green sheets during firing
Data Source
AI summary
A multilayer coil component includes a multilayer body including insulating layers and coil conductors laminated in a lamination direction and having a coil formed therein and outer electrodes each of which is at a surface of the multilayer body and electrically connected to the coil. The multilayer body has first and second end surfaces facing each other in a length direction, first and second main surfaces facing each other in a height direction perpendicular to the length direction, and first and second side surfaces facing each other in a width direction perpendicular to the length and height directions. The outer electrodes includes the first outer electrode extending from at least a portion of the first end surface to a portion of the first main surface and the second outer electrode extending from at least a portion of the second end surface to a portion of the first main surface.