LED Display Backplane Fixing Structure for Bonding Alignment
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Solution Overview
Problem
During the manufacturing of light-emitting diode display panels, the thermal expansion of the adhesive layer caused by laser irradiation leads to shifting of light-emitting diode elements, resulting in poor bonding yield and connection issues between the elements and the driving backplane.
Innovation Solution
Incorporating a first fixing element on the driving backplane, which abuts the adhesive layer of the light-emitting element substrate, to stabilize the position of the light-emitting diode elements during the bonding process, ensuring precise alignment and reducing thermal expansion effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If laser is used to irradiate the temporary base and light-emitting diode element for eutectic bonding, then electrical connection between electrode and pad is achieved, but the adhesive layer undergoes thermal expansion causing position shift of light-emitting diode element
Solution Approach 1:
The patent applies preliminary action by pre-heating the temporary base before laser irradiation. This pre-heating reduces the thermal gradient and minimizes thermal expansion of the adhesive layer during subsequent laser bonding, thereby preventing position shift of the light-emitting diode element and improving bonding yield
Solution Approach 2:
The patent changes the temperature parameter by implementing a pre-heating step that raises the baseline temperature of the temporary base. This parameter change reduces the relative thermal expansion during laser irradiation, maintaining position accuracy while achieving reliable electrical connection
2Productivity
If laser irradiation is applied for eutectic bonding, then electrical connection is established, but thermal expansion of adhesive layer causes position shift resulting in connection failure
Solution Approach 1:
The pre-heating step performed before laser irradiation serves as a preliminary action that prepares the temporary base in an optimal thermal state. This reduces thermal shock and minimizes adhesive layer expansion during bonding, ensuring both manufacturing efficiency and connection reliability
3Ease of manufacture
If the light-emitting diode element position shifts during bonding, then manufacturing process continues, but electrode cannot connect smoothly with pad
Solution Approach 1:
By pre-heating the temporary base before bonding, the patent prevents thermal expansion-induced position shifts during the bonding process. This ensures alignment accuracy is maintained throughout the continuous manufacturing process, allowing electrode-to-pad connection without interruption or failure
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 solution significantly improves the bonding yield by maintaining the position of light-emitting diode elements, ensuring successful electrical connections and enhancing the overall manufacturing efficiency of the display apparatus.
Implementation Method 1
the adhesive layer of the temporary base will be heated to cause thermal expansion, so that the position of the light-emitting diode element disposed on the adhesive layer of the temporary base is shifted
Implementation Method 2
laser may be used to irradiate the temporary base and the light-emitting diode element, so that the electrode of the light-emitting diode element and the pad of the driving backplane are eutectic bonded
Data Source
AI summary
A display apparatus includes a carrier base, a pixel driving circuit, an insulating layer, a pad group, a light-emitting element, and a first fixing element. The pixel driving circuit is disposed on the carrier base. The insulating layer is disposed on the pixel driving circuit. The pad group is disposed on the insulating layer and is electrically connected to the pixel driving circuit. The light-emitting element is electrically connected to the pad group. The first fixing element is disposed on the insulating layer and at least located on two opposite sides of the pad group. In a direction perpendicular to the carrier base, the light-emitting element has a height HLED, the first fixing element has a height HPS1, a pad of the pad group has a thickness HPAD. HLED, HPS1, and HPAD satisfy:HLED≤_HPS1≤_1.4⋅HLED+HPAD.Or, HLED, HPS1, and HPAD satisfy:HLED+90μm≤_HPS1≤_1.4⋅HLED+HPAD+90μm.