Micro LED Repair Method Using Pre-formed Soldering Layers
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional micro LED display repair methods face challenges with insufficient bonding strength between the second micro LED and the circuit due to multiple reflow processes of the second soldering layer, which can lead to short circuits and require precise alignment, reducing repair yield.
Innovation Solution
The proposed method involves a micro LED display with a first soldering layer covering the entire top surface of the first circuit layer and a smaller second soldering layer on the second micro LED, which bonds directly to the second circuit layer without a second reflow, ensuring stronger bonding and avoiding short circuits by eliminating the need for a solder resist layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If the second soldering layer undergoes multiple reflow processes to bond the second micro LED, then the repair procedure can be completed, but the bonding strength becomes insufficient and short circuits may occur
Solution Approach 1:
The patent applies preliminary action by forming the second soldering layer on the second micro LED before transfer, and performing a preliminary reflow process before the actual repair. This pre-prepared soldering layer with pre-formed bonding structure ensures strong bonding strength during the repair process without requiring multiple reflow operations, thus resolving the contradiction between repair completion and bonding reliability
2Reliability
If a solder resist layer is provided to prevent short circuits, then short circuit risk is reduced, but the alignment precision requirement increases
Solution Approach 1:
The patent extracts and removes the solder resist layer from the display substrate structure. Instead of using a solder resist layer to prevent short circuits, the invention relies on the precisely controlled second soldering layer area and the spatial arrangement of circuit layers. This extraction eliminates the alignment precision problems associated with solder resist while maintaining short circuit prevention through alternative means
Solution Approach 2:
The patent applies local quality by creating a second soldering layer with a specific area that is smaller than the first soldering layer area. This localized, controlled soldering area ensures that the soldering material is confined to a precise region, preventing short circuits between adjacent circuits without requiring a solder resist layer, thus resolving the contradiction between short circuit prevention and alignment precision
3Manufacturing precision
If the second soldering layer area is reduced to improve alignment, then alignment tolerance increases, but the bonding strength may be compromised
Solution Approach 1:
The patent applies parameter changes by optimizing the area of the second soldering layer to be smaller than the first soldering layer area. This parameter adjustment achieves two objectives simultaneously: it provides sufficient alignment tolerance due to the smaller target area, and it maintains strong bonding strength through the concentrated soldering material and preliminary reflow process. The parameter optimization resolves the contradiction between alignment tolerance and bonding strength
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 enhances the bonding strength and alignment tolerance, increasing repair yield and ensuring the reliability of the micro LED display by preventing short circuits and improving precision during the repair process.
Implementation Method 1
the first soldering layer undergoes a first reflow process to bond each of the first micro LEDs to the circuit in each of the pixel areas through the first soldering layer
Implementation Method 2
The second soldering layer undergoes a second reflow process to bond the second micro LED to the circuit in the pixel area with a broken spot
Data Source
AI summary
A micro LED display includes a display substrate, a first soldering layer, at least one second soldering layer, first micro LEDs and at least one second micro LED. The display substrate includes a substrate having a plurality of pixel areas, a first circuit layer and a second circuit layer, and the first circuit layer and the second circuit layer are arranged in each pixel area. The first soldering layer is disposed on the first circuit layer, and the second soldering layer is disposed on the second micro LED. An arranging area of the first soldering layer is greater than an arranging area of the second soldering layer. The first micro LEDs is bonding to the first circuit layer in each pixel area through the first soldering layer. The second micro LED is bonding to the second circuit layer of one of the pixel areas through the second soldering layer.