Chip Resistor Bulk Mounting via Cap-Shaped Electrodes
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Solution Overview
Problem
Existing chip resistors face challenges in bulk mounting due to inadequate side-surface electrode formation, reduced substrate thickness, shallow groove depth, poor self-alignment, and the Manhattan phenomenon, as well as complex production methods that lead to resistance variations and trimming difficulties.
Innovation Solution
A chip resistor design featuring a rectangular parallelepiped ceramic substrate with front electrodes, a resistive element, and cap-shaped end-surface electrodes, where the insulating substrate and protective layer form a laminate with a square cylindrical shape, allowing for stable bulk mounting without directional dependency and enabling easy resistance value adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If side-surface electrodes are formed on non-electrode surfaces to enable bulk mounting, then mounting adaptability is improved, but electrode formation complexity and production difficulty increase
Solution Approach 1:
The end-surface electrodes are designed to extend not only on the end surfaces but also on the side surfaces of the insulating substrate. This multi-functional electrode design allows the chip resistor to be mounted in any orientation (bulk mounting) while maintaining electrical connectivity, thereby achieving mounting adaptability without significantly increasing production complexity
Solution Approach 2:
The electrodes transition from being confined to two-dimensional end surfaces to extending into the third dimension by covering side surfaces as well. This dimensional extension enables the electrodes to make contact with solder paste regardless of the mounting orientation, solving the adaptability problem
2Volume of moving object
If substrate thickness is reduced to miniaturize the chip resistor, then device size is improved, but groove depth becomes shallow making electrode formation difficult
Solution Approach 1:
Instead of forming deep grooves in the thin substrate, the electrode design extends onto the side surfaces of the substrate. This dimensional approach allows electrodes to be formed on the exposed side surfaces without requiring deep groove formation, thereby maintaining manufacturing precision while achieving miniaturization
3Adaptability or versatility
If cap-shaped end-surface electrodes extend to all surfaces including upper surface, then bulk mounting capability is improved, but the Manhattan phenomenon occurs causing unstable mounting
Solution Approach 1:
The end-surface electrodes are designed with asymmetric extension: they extend onto the side surfaces to enable bulk mounting, but deliberately do not extend onto the upper surface. This asymmetric design prevents the Manhattan phenomenon (where the chip stands upright during mounting) while maintaining bulk mounting capability, thereby ensuring mounting stability
4Adaptability or versatility
If complex production methods with multiple green sheets are used to achieve cylindrical shape, then bulk mounting adaptability is improved, but resistance value variation increases and trimming becomes difficult
Solution Approach 1:
The invention extracts and eliminates the complex multi-green-sheet bonding process and cylindrical shaping steps from the production method. By using a simpler substrate formation process while maintaining the essential bulk mounting adaptability through electrode design, the invention reduces resistance value variations and facilitates trimming operations
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 design enables stable bulk mounting on any surface, reduces resistance variations, and simplifies the production process by forming end-surface electrodes with consistent dimensions on all surfaces, preventing the Manhattan phenomenon and improving connection reliability.
Implementation Method 1
after a solder paste is printed on lands provided on the circuit board, the external electrodes of the chip resistor are mounted on the lands with the back electrodes down. In this state, the solder paste is melted and solidified.
Data Source
AI summary
Provided is a chip resistor including: a rectangular parallelepiped insulating substrate which is made of ceramics; a pair of front electrodes which are provided on lengthwise opposite end portions in a front surface of the insulating substrate; a resistive element which is provided between and connected to the two front electrodes; a protective layer which is made of a resin and which entirely covers the front surface of the insulating substrate including the two front electrodes and the resistive element; and a pair of cap-shaped end-surface electrodes which are provided on the lengthwise opposite end portions of the insulating substrate to establish electrical continuity to the front electrodes respectively; wherein: a chip element assembly in which the insulating substrate and the protective layer are laminated on each other but the end-surface electrodes have not been formed yet has an external shape substantially like a square cylinder.