Underfill Flow Control via Protrusions in Light-Emitting Devices
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Solution Overview
Problem
Conventional methods for manufacturing light-emitting devices require a large underfill-arranging portion to ensure accurate filling of the underfill, leading to an increase in the size of the light-emitting device.
Innovation Solution
The method involves forming protrusions, such as dummy bumps or thicker portions of electrodes or substrate, to guide the underfill through capillary action from a position opposite the light-emitting element, allowing for precise filling without increasing the device size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a wide underfill-arranging portion is provided to ensure accurate filling of underfill, then the filling accuracy is improved, but the size of the light-emitting device increases
Solution Approach 1:
The invention introduces protrusions that extend in the depth dimension (vertical direction) from the surface of the circuit board. These protrusions create a three-dimensional structure that guides underfill flow without requiring additional horizontal space. The protrusions act as physical guides that channel the underfill into the gap between the light-emitting element and substrate, achieving precise filling while maintaining a compact device footprint.
Solution Approach 2:
The protrusions serve as intermediary structures between the underfill dispensing location and the target gap area. They mediate the underfill flow by providing a physical pathway and capillary action channels, ensuring the underfill reaches the correct location without requiring a large arranging portion. The protrusions translate the dispensed underfill into controlled flow toward the gap area.
2Manufacturing precision
If the dispenser is brought close to the light-emitting element for accurate dispensing, then the dispensing precision is improved, but the light extraction efficiency decreases due to underfill adhesion
Solution Approach 1:
The protrusions act as intermediary structures that enable the dispenser to remain at a safe distance from the light-emitting element while still achieving accurate underfill delivery. The protrusions extend into the gap area and provide capillary channels that draw the underfill toward the target location, eliminating the need for close dispenser positioning and preventing underfill adhesion to the light-emitting element surface.
Solution Approach 2:
The invention replaces the mechanical approach of close dispenser positioning with a capillary action-based system. Instead of relying on the dispenser's proximity to control underfill flow, the protrusions utilize capillary forces to guide the underfill automatically, substituting mechanical precision requirements with passive physical phenomenon-based control.
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 approach enables accurate filling of the underfill without enlarging the light-emitting device, preventing light extraction efficiency loss and minimizing the risk of underfill adhesion to unintended surfaces.
Implementation Method 1
allowing the dispensed underfill to flow toward the light-emitting element by a capillary action through the gap between the p- and n-electrodes of the circuit board
Data Source
AI summary
A method of manufacturing a light-emitting device that includes a circuit board with p- and n-electrodes formed on a surface of a substrate and a light-emitting element connected to the p- and n-electrodes of the circuit board via a conductor member. The method includes forming two protrusions facing each other on both sides of a gap between the p- and n-electrodes of the circuit board, and dispensing a underfill at a position on an opposite side to the light-emitting element with respect to the two protrusions, allowing the dispensed underfill to flow toward the light-emitting element by a capillary action through the gap between the p- and n-electrodes of the circuit board while contacting the protrusions, and filling, by the capillary action, a gap between the circuit board and the light-emitting element with the underfill reaching a bottom of the light-emitting element.