Resistor Electrode Overlap Structure for Thermal Stress Relief
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Solution Overview
Problem
The separation of electrodes overlapping with the protective film in resistors due to thermal stress leads to a decline in heat dissipation performance and fluctuation in resistance value.
Innovation Solution
A resistor design featuring a resistive element with insulation and protective films, and electrodes spaced apart with intermediate layers containing conductive synthetic resin, where the intermediate layers cover and are in contact with the protective film, mitigating thermal stress and maintaining adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the surface area of electrodes is increased to improve heat dissipation performance, then heat dissipation is improved, but the size of the resistor increases
Solution Approach 1:
The electrode structure transitions from a single-plane configuration to a three-dimensional overlapping arrangement. The first and second electrodes extend in the first direction and overlap in the second direction, utilizing vertical stacking to increase effective heat dissipation area without expanding the resistor's footprint on the circuit board.
Solution Approach 2:
The electrode configuration embeds one electrode structure within the spatial envelope of another. The first electrode is positioned beneath the second electrode in the thickness direction, with both electrodes overlapping in plan view, creating a nested arrangement that maximizes heat dissipation surface area within a compact volume.
2Area of stationary object
If electrodes are disposed to overlap with protective film to suppress size increase, then resistor size is reduced, but electrode separation occurs due to thermal stress
Solution Approach 1:
An intermediate layer is introduced between the first electrode and the protective film, and another intermediate layer is introduced between the second electrode and the protective film. These intermediate layers serve as buffer zones that accommodate thermal expansion differences and reduce stress concentration at the electrode-protective film interface, preventing separation while maintaining the overlapping configuration.
Solution Approach 2:
The electrode assembly becomes a composite structure consisting of the electrode material, intermediate layer material, and protective film material. This multi-material construction allows each layer to contribute its specific properties: the electrode provides electrical conductivity and heat dissipation, the intermediate layer provides stress relief and adhesion, and the protective film provides insulation and mechanical protection.
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
Prevents electrode separation, enhances heat dissipation, maintains resistance stability, and improves adhesion strength, thereby reducing resistance fluctuations and increasing mounting strength on circuit boards.
Implementation Method 1
the portion of the pair of electrodes contacting the protective film may be separated, during the use of the resistor, because of thermal stress generated at the interface between the protective film and each of the pair of electrodes
Implementation Method 2
When the resistor is made to detect a larger current, the amount of heat generated by the resistive element will increase
Data Source
AI summary
A resistor includes a resistive element, an insulation plate, a protective film, and a pair of electrodes. The resistive element includes a first face and a second face arranged to face in opposite directions in a thickness direction. The insulation plate is on the first face, and the protective film on the second face. The electrodes are spaced apart in a first direction perpendicular to the thickness direction, and held in contact with the resistive element. Each electrode includes a bottom portion opposite to the insulation plate with respect to the resistive element in the thickness direction. Each bottom portion overlaps with a part of the protective film as viewed in the thickness direction. The resistor further includes a pair of intermediate layers spaced apart in the first direction. The intermediate layers are formed of a material electrically conductive and containing a synthetic resin. Each intermediate layer includes a cover portion covering a part of the protective film. The cover portion of each intermediate layer is disposed between the protective film and the bottom portion of one of the electrodes.