SMD Resistor Lateral Contact and Adhesive Insulation
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Solution Overview
Problem
Conventional SMD resistors face issues with intricate electrical connections, mechanical weakening due to substrate incisions, high electroplating costs, and lack of visual inspection for soldering points, which limit miniaturization and increase production costs.
Innovation Solution
The SMD resistor design features laterally exposed connection parts for visible soldering, a planar metallic support element with a resistive film on the underside, and a V-shaped or meandering incision in the support element to prevent current flow, allowing for visual inspection and improved mechanical stability while using a copper-manganese alloy for the resistive material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a transverse incision is made in the substrate to prevent current flow between support elements, then electrical insulation is achieved, but mechanical strength is weakened
Solution Approach 1:
An adhesive layer is introduced as an intermediary substance to fill the incision and provide both electrical insulation and mechanical reinforcement. The adhesive layer bonds the resistive film to the substrate while simultaneously strengthening the incised area, preventing current leakage and restoring mechanical integrity.
Solution Approach 2:
The substrate structure becomes a composite system combining the metallic substrate, adhesive layer, and resistive film. This composite structure allows the adhesive to serve dual functions: electrical insulation in the incision and mechanical reinforcement, resolving the contradiction between electrical performance and structural strength.
2Strength
If the substrate thickness is increased to provide mechanical stability, then structural integrity is improved, but miniaturization is limited
Solution Approach 1:
The composite structure of substrate plus adhesive layer plus resistive film creates a mechanically reinforced assembly that achieves high structural integrity at reduced thickness. The adhesive layer acts as a bonding matrix that distributes mechanical loads, allowing the overall component to be thinner while maintaining or improving mechanical stability.
Solution Approach 2:
The resistive film is structured as a meandering path rather than a solid layer, segmenting the resistive material to reduce overall thickness while maintaining electrical function. This segmented approach allows the component to be more compact and thinner, enabling miniaturization without sacrificing mechanical stability.
3Reliability
If electroplating is used to create conductive contacts, then electrical conductivity is improved, but production cost increases
Solution Approach 1:
The expensive electroplating process is extracted and replaced with a screen-printing process using conductive paste. This substitution eliminates the need for complex electroplating equipment and multiple plating stages, significantly reducing production costs while maintaining adequate electrical conductivity for the application.
Solution Approach 2:
Conductive paste is used as a disposable, screen-printable material instead of requiring permanent electroplating infrastructure. The paste can be applied directly through screen printing and cured, providing a low-cost alternative that eliminates expensive electroplating equipment and process steps.
4Reliability
If connection parts are placed on the underside only, then electrical connection is achieved, but visual inspection of soldering is prevented
Solution Approach 1:
The connection parts are positioned to extend from the underside to the side surface of the component, utilizing the lateral dimension for visibility. This three-dimensional arrangement allows the connection parts to remain electrically connected to the underside while becoming accessible for visual inspection from the side, solving both requirements simultaneously.
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 enables visual inspection of soldering points, enhances mechanical stability, reduces electroplating costs, and allows for miniaturization with efficient heat dissipation and resistance adjustment, while maintaining low resistance values.
Implementation Method 1
an electrically insulating adhesive layer 3 is applied to the upper side of the substrate 2, and then serves to bond a resistive film to the upper side of the substrate 2
Implementation Method 2
In the production process an electrically insulating adhesive layer 3 is applied to the upper side of the substrate 2, and then serves to bond a resistive film to the upper side of the substrate 2. The resistive film is then structured by an etching process
Implementation Method 3
The support elements 2.1, 2.2 therefore here form the electrical connection parts of the SMD resistor 1, which can be soldered onto solder pads 7, 8
Data Source
AI summary
The invention relates to a resistor (18), particularly an SMD resistor, including a planar, metallic support element (19) that has a top surface and a bottom surface, a planar resistor element (21) which is made of a resistive material and is disposed on the bottom surface of the support element (19), and at least two separate metallic connecting parts (23, 23) which electrically contact the resistor element (21) and are arranged in part on the bottom surface of the support element (19). The connecting parts (22, 23) are laterally exposed on the resistor (18) and can be laterally wetted in a visible manner by a solder. The invention further relates to a corresponding production method.