Light-Emitting Module Wiring Pad Compression for Lower Resistance
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Solution Overview
Problem
Conventional methods for reducing the resistance of electrically conductive paste in through holes of a printed circuit board have limitations, necessitating further improvements to achieve lower resistance and thinner connections.
Innovation Solution
A method involving the use of a board with circuit patterns and bottomed holes, application of electrically conductive paste through a mask, followed by thermal compression to reduce the thickness of the paste, and covering it with insulating resin to form a light-emitting module with reduced resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermal compression is applied only in through holes or on the board, then the thickness is reduced, but the resistance of electrically conductive paste cannot be sufficiently reduced
Solution Approach 1:
The patent extends thermal compression from traditional two-dimensional application (only in through holes or only on the board surface) to three-dimensional application that simultaneously covers both the through hole interior and the surrounding board surface, achieving comprehensive resistance reduction in all critical areas
Solution Approach 2:
The patent combines the thermal compression treatment for through holes with surface treatment into a single integrated process step, applying compression to both regions simultaneously to reduce resistance in the electrically conductive paste throughout the entire connection path
2Reliability
If electrically conductive paste is supplied into bottomed holes through mask opening, then electrical connection is established, but the paste thickness remains high resulting in increased resistance
Solution Approach 1:
The patent changes the physical parameters of the electrically conductive paste by applying thermal compression, which reduces the paste thickness and increases its density, thereby lowering resistance while maintaining electrical connection reliability
Solution Approach 2:
The patent replaces simple paste deposition with a combined thermal-mechanical compression process, using heat and pressure to transform the paste from a high-thickness state to a low-thickness, low-resistance state
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 method results in a light-emitting module with high connection reliability and reduced overall thickness and resistance, facilitated by the controlled thickness of the intervening portions of the electrically conductive paste.
Implementation Method 1
performing thermal compression to the electrically conductive paste on the portion of the surface of each of the wiring pads, and hardening the electrically conductive paste
Implementation Method 2
hardening the electrically conductive paste such that a thickness of the electrically conductive paste on the portion is smaller than the electrically conductive paste at the timing of being disposed
Data Source
Figure 1~2
Figure 3
Figure 4A~4B
AI summary
A method for manufacturing a light-emitting module includes a step of providing a bonded board including a board including, on a first surface, a circuit pattern and wiring pads that are continuous with the circuit pattern and each have bottomed holes and light-emitting segments connected on a second surface of the board with an adhesive sheet interposed therebetween and including an array of light-emitting devices; a step of supplying electrically conductive paste inside the bottomed holes and on portions of the surface of the wiring pad around the bottomed holes through openings of a mask; and a step of performing thermal compression to harden the electrically conductive paste such that the thickness of the electrically conductive paste on the portions of the surface of the wiring pad is smaller than the electrically conductive paste at the timing of being disposed through the openings of the mask.