Inductor Double Insulating Layer Void Reduction
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Solution Overview
Problem
Existing thin film inductors face issues with voids in the gaps of the conductive coil during the formation of the insulating layer, leading to reduced reliability under high temperature and moisture conditions, and increased DC resistance due to insufficient insulating margin.
Innovation Solution
A double insulating layer structure is implemented, with a lamination part formed in the gaps of the conductive coil and an insulating coating part covering the entire surface, using a material like epoxy, to reduce voids and decrease the total thickness of the insulating layer, enhancing the reliability and inductance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single insulating layer is formed using vacuum impregnation method, then the insulating layer can be applied to the conductive coil, but voids are generated in the gaps of the conductive coil leading to reduced reliability
Solution Approach 1:
The insulating layer is divided into two separate layers: a first insulating layer formed by vacuum impregnation method, and a second insulating layer formed by coating method. This segmentation allows each layer to compensate for the deficiencies of the other, with the first layer providing base insulation and the second layer filling voids and providing additional protection.
Solution Approach 2:
The patent uses composite insulating structure combining two different insulating layers with different formation methods. The first insulating layer (formed by vacuum impregnation) and second insulating layer (formed by coating) work together to provide comprehensive insulation, eliminating voids and improving reliability under harsh conditions.
2Reliability
If a thick insulating layer is formed to ensure sufficient insulating margin, then insulation reliability is improved, but DC resistance increases due to longer current path
Solution Approach 1:
The insulating structure provides different thicknesses at different locations: the first insulating layer fills the gaps between coil windings where insulation is most critical, while the second insulating layer provides additional insulation on the outer surface. This local quality optimization ensures sufficient insulating margin where needed without uniformly increasing the current path length.
Solution Approach 2:
The patent transitions from a single-dimensional insulating approach to a two-dimensional insulating structure with layers at different positions (inner gaps and outer surface). This dimensional change allows insulation to be provided at multiple locations simultaneously, reducing the need for excessive thickness in any single location and thereby minimizing the impact on DC resistance.
3Reliability
If expensive insulating material is used to ensure complete gap filling and high reliability, then voids are prevented, but manufacturing cost increases
Solution Approach 1:
The insulating function is segmented between two layers formed by different methods. The first layer (vacuum impregnation) provides base insulation at lower cost, while the second layer (coating) provides additional protection and void filling. This segmentation avoids the need to use expensive materials or methods throughout the entire insulating structure.
Solution Approach 2:
The patent changes the formation method parameter between the two insulating layers. The first layer uses vacuum impregnation (lower cost, good gap penetration), while the second layer uses coating (lower cost, good surface coverage). This parameter change allows optimization of both cost and performance by selecting appropriate formation methods for different layer requirements.
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 double insulating layer structure effectively prevents voids, improves the reliability of the inductor, and increases inductance by reducing the insulating margin, while also decreasing manufacturing costs through the use of a less expensive material.
Implementation Method 1
a lamination part formed in a gap of the conductive coil and on an upper surface thereof
Implementation Method 2
an insulating coating part formed to enclose an overall surface of the conductive coil
Data Source
AI summary
An inductor may include: a body, and a first and a second external electrode formed on end surfaces of the body. The body may include a coil support layer, a conductive coil formed on at least one surface of the coil support layer, a lamination part formed in a gap of the conductive coil and on an upper surface thereof, an insulating coating part formed to enclose an overall surface of the conductive coil on which the lamination part is formed, and upper and lower cover layers covering the overall surface of the conductive coil on which the insulating coating part is formed.