Inductor Multiplex Winding Structure Reducing Resistance
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Solution Overview
Problem
Existing inductors face challenges in reducing electrode resistance and increasing multifunctionality while maintaining a small size, as through-hole conductors and conductive paste limitations hinder resistance reduction and space constraints limit winding increases.
Innovation Solution
The inductor features a resin layer with a multiplex winding structure comprising metal pins and boards of lower specific resistance, allowing for a three-dimensional wiring configuration that increases windings without the need for through-hole conductors, enabling reduced size and enhanced performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If through-hole conductors are used for interlayer connection, then the inductor structure is simple to manufacture, but the connection resistance is high and cannot be reduced further
Solution Approach 1:
The patent changes the material parameter from conductive paste (with metal filler and organic solvent) to pure metal for the via conductors. This parameter change reduces the specific resistance from that of paste-filled vias to pure metal conductivity, thereby reducing the connection resistance between upper and lower wiring patterns.
Solution Approach 2:
The patent extracts the organic solvent component from the conductive paste mixture, using only the metal filler portion to form the via conductors. This extraction eliminates the high-resistance paste matrix while retaining the conductive metal, achieving lower resistance connections.
2Reliability
If the number of coil windings is increased to improve inductor characteristics, then the inductance performance is improved, but the space required on the main surfaces increases
Solution Approach 1:
The patent transitions from two-dimensional planar winding patterns on the main surfaces to three-dimensional vertical stacking of wiring patterns across multiple layers. By utilizing the vertical dimension with via conductors connecting upper and lower wiring patterns, the coil can achieve more windings without increasing the horizontal surface area, thus improving inductor characteristics while maintaining a compact footprint.
Solution Approach 2:
The patent implements a nested multi-layer structure where upper wiring patterns are positioned above and connected to lower wiring patterns through via conductors. This nesting of wiring layers in the vertical direction allows the coil windings to be stacked compactly, increasing the effective number of windings within a reduced surface area.
3Ease of manufacture
If conductive paste is used to fill via holes, then the via conductors can be formed, but the specific resistance is high due to voids and gaps in the metal area
Solution Approach 1:
The patent replaces the conductive paste material (which contains voids and gaps) with pure metal for via conductor formation. This substitution eliminates the inherent defects of paste-filled vias, achieving lower specific resistance and more reliable electrical connections.
Data Source
AI summary
A small-sized inductor with desired characteristics is provided. An inductor 1a includes a resin layer 3 and an inductor electrode 6, which includes an inner winding portion 6a and an outer winding portion 6b. The inner winding portion 6a and the outer winding portion 6b forming the inductor electrode 6 include the metal pins 7a to 7d and the wiring boards 8a to 8d. Here, the inner winding portion 6a and the outer winding portion 6b include the metal pins 7a to 7d and the wiring boards 8a to 8d, which have lower specific resistance than conductive paste or plating. This structure thus can reduce the resistance of the entirety of the inductor electrode 6, and improve the characteristics of the inductor 1a. The inductor 1a can reduce its size by including the inductor electrode 6 wound to have a multiplex winding structure.