Non-reciprocal Circuit Element With Through Hole
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Solution Overview
Problem
The existing non-reciprocal circuit elements with ferritic magnetic plates face challenges in achieving consistent surface roughness for conductive film adhesion, leading to peeling issues due to thermal contraction differences between the magnetic plate and resin materials, and require lengthy processing times for metallic material filling.
Innovation Solution
A non-reciprocal circuit element design featuring a magnetic plate with a through hole that has an empty space, allowing partial exposure of a conductive film, and using an underfill material between the magnetic plate and circuit board to reduce thermal stress and processing time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the through hole is filled with metallic material to provide electrical conduction, then the electrical conductivity is improved, but the processing time is significantly increased
Solution Approach 1:
The patent extracts the metallic filling material from the through hole, leaving it empty while maintaining electrical conductivity through the conductive film on the inner wall surface. This eliminates the time-consuming metallic filling process while preserving the essential electrical conduction function.
Solution Approach 2:
Instead of completely filling the through hole with metallic material, the patent applies conductive film partially on the inner wall surface, which is sufficient to provide the required electrical conductivity without the excessive processing time of complete metallic filling.
2Productivity
If the through hole is filled with resin material to reduce processing time, then the processing time is reduced, but the conductive film may peel off due to thermal contraction differences
Solution Approach 1:
The patent removes the resin filling material from the through hole, leaving it empty. This eliminates the thermal contraction issue that causes conductive film peeling while still maintaining electrical conductivity through the conductive film on the inner wall surface.
Solution Approach 2:
The conductive film on the inner wall surface acts as an intermediary that provides electrical conductivity without requiring the problematic resin filling material, thus avoiding thermal contraction issues while maintaining the necessary electrical function.
3Reliability
If the inner wall surface of the through hole has smooth and consistent surface roughness to improve conductive film adhesion, then the adhesiveness is improved, but it is difficult to achieve due to the fragility of ferritic sintered material
Solution Approach 1:
The conductive film is applied to the inner wall surface of the through hole before final assembly, ensuring proper adhesion is established early in the manufacturing process. This preliminary action allows the conductive film to bond properly to the magnetic plate surface without requiring perfectly smooth surface roughness that is difficult to achieve with ferritic sintered material.
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 design enhances processing efficiency by eliminating the need for lengthy metallic material filling and reduces the risk of conductive film peeling, ensuring consistent adhesion and quality.
Implementation Method 1
there is a large difference in coefficient of thermal expansion between the magnetic plate and the resin material, which may cause a thermal contraction of the resin material
Implementation Method 2
in order to provide electrical conduction between the permanent magnet side and the solder bump side of the magnetic plate, through holes are formed extending from one main surface to the other main surface of the magnetic plate, each through hole being filled with a conductive film
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
A non-reciprocal circuit element (100) includes a magnetic plate (1), a permanent magnet (3), and a circuit board (5). The permanent magnet (3) is connected to one main surface (1A) of the magnetic plate (1), and the circuit board (5) is connected to the other main surface (1B) of the magnetic plate (1), with a solder bump (11) lying between the circuit board (5) and the other main surface (1B). The permanent magnet (3) can control the transmission of electrical signal from each of a plurality of signal conductors (41) of circuit board (5) to a corresponding one of a plurality of input/output terminals (31) of the magnetic plate (1). The non-reciprocal circuit element (100) further includes an underfill material (40) arranged between the magnetic plate (1) and the circuit board (5). The magnetic plate (1) has a through hole (25) formed therein, the through hole (25) extending from one main surface (1A) to the other main surface (1B). The through hole (25) has an empty space in which at least a part of a conductive film (27) arranged in the through hole (25) is exposed.