Surface Mount Component Lead Tip Resin Coating
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Solution Overview
Problem
Conventional surface-mount electronic components with exposed cut surfaces of connecting leads lead to solder bridges, electric discharge, reduced mounting density, corrosion, and decreased moisture resistance, due to the exposure of these surfaces during the manufacturing process.
Innovation Solution
A surface-mount electronic component design where the cut tip surfaces of connector leads are covered with a synthetic resin coating layer, and a manufacturing method involving a lead frame with prearranged sites for electrode terminals, electrical connection of a semiconductor element, sealing with synthetic resin, creating a hollow groove, and filling it with resin to form a cover layer that seals the cut surfaces, preventing exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the connecting leads are cut at the side surfaces of the package to separate individual electronic components, then the manufacturing process is simplified and components can be separated efficiently, but the cut surfaces of the connecting leads become exposed causing solder bridges, electric discharge, and corrosion
Solution Approach 1:
The patent applies preliminary action by forming the resin coating layer on the connecting leads before the cutting process. The lead frame is coated with resin material, then cut to separate individual components, ensuring the cut surfaces are already protected. This prevents exposure of metal surfaces that would otherwise lead to corrosion and solder bridges.
Solution Approach 2:
The resin coating layer acts as an intermediary substance between the metal connecting leads and the external environment. This intermediate layer prevents direct contact between the metal surfaces and solder or moisture, eliminating solder bridges and corrosion while allowing the cutting process to proceed normally.
2Productivity
If the cut surfaces of connecting leads are exposed, then component separation is achieved, but solder bridges are produced between the cut surfaces and wiring patterns during mounting and soldering
Solution Approach 1:
The resin coating is applied to the connecting leads before cutting, so that when the leads are cut to separate components, the freshly exposed cut surfaces are already protected by the resin layer. This preliminary protection prevents solder bridges during subsequent mounting operations.
Solution Approach 2:
The resin coating serves as an intermediary barrier between the metal connecting leads and the solder material. This intermediate layer prevents direct contact between solder and the connecting lead surfaces, eliminating solder bridge formation while maintaining component separation efficiency.
3Quantity of substance
If multiple electronic components are arranged side by side with exposed cut surfaces, then production density is maintained, but electric discharge occurs between adjacent components and solder bridges are produced
Solution Approach 1:
The resin coating is applied to all connecting leads before the cutting and assembly process, ensuring that when multiple components are arranged side by side, the cut surfaces are already insulated. This prevents electric discharge between adjacent components while maintaining high mounting density.
Solution Approach 2:
The resin coating acts as an intermediary insulating layer between adjacent electronic components. This intermediate barrier prevents electric discharge and solder bridges between neighboring components, allowing them to be arranged closely without compromising electrical insulation or reliability.
4Ease of manufacture
If the connecting leads are made with narrow width and small thickness to facilitate cutting, then component separation is improved, but the cut surfaces are more vulnerable to corrosion and solder bridges
Solution Approach 1:
The resin coating is applied to the narrow connecting leads before cutting, so that when the thin leads are cut to separate components, the vulnerable cut surfaces are immediately protected. This preliminary protection is especially important for thin leads that would otherwise be highly susceptible to corrosion.
Solution Approach 2:
The resin coating serves as a protective intermediary layer on the narrow connecting leads. This intermediate barrier shields the thin metal surfaces from corrosion and moisture damage, compensating for the increased vulnerability introduced by using narrow, thin leads for easier cutting.
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 solder bridges and electric discharge between components, allows for higher mounting density, reduces corrosion, and enhances moisture resistance by fully sealing the connecting leads within the package, while maintaining efficient production without increasing costs or pitch intervals.
Implementation Method 1
a package made of synthetic resin for sealing the electrode terminals and the semiconductor element
Implementation Method 2
each of the electrode terminals is at least partially exposed to serve as a mounting surface for soldering at a lower surface of the package... the cut tip surface covered by a coating layer of synthetic resin
Data Source
AI summary
The electric component includes at least a set of electrode terminals 2, 3, a semiconductor element 4 electrically connected with the set of electrode terminals, and a package 6 made of synthetic resin and sealing the electrode terminals and the semiconductor element with part of a lower surface of each of the electrode terminals exposed at a lower surface of the package. A cover layer 11 made of synthetic resin is formed to cover a cut surface of a tip of a connector lead remainder extending integrally outward from the each of the electrode terminals. Thus, disadvantages resulting from exposure of the cut surface of the tip of the connector lead remainder are eliminated.