Light Emitting Device Transfer via Laser Ablation
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Solution Overview
Problem
Current methods for forming light emitting device assemblies are inefficient in transferring and bonding light emitting devices onto backplane substrates, leading to challenges in achieving precise alignment and minimizing height differentials between devices, which affects the overall performance and reliability of the assembly.
Innovation Solution
A method involving the use of transfer substrates with release layers and bonding material layers, where light emitting devices are selectively transferred and bonded onto backplane substrates using laser irradiation and ablation to create conductive bonding structures with varying heights, allowing for precise alignment and reduced height differentials between devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional transfer and bonding methods are used, then the assembly process is simpler, but alignment precision and height differential control deteriorate
Solution Approach 1:
The patent applies preliminary action by pre-forming bonding protrusions with varying heights on the transfer substrate before transferring the light emitting devices. This pre-prepared structure enables precise alignment and controlled height differentials during the bonding process, eliminating the need for complex post-adjustment operations while maintaining high manufacturing precision.
Solution Approach 2:
The patent implements local quality by creating bonding protrusions with different heights at different locations on the transfer substrate. Each protrusion's height is specifically designed to match the requirements of the corresponding light emitting device, enabling precise control over the final assembly's topography and alignment while simplifying the overall transfer process.
2Productivity
If selective laser irradiation and ablation are used, then transfer efficiency and bonding precision improve, but energy consumption increases
Solution Approach 1:
The patent applies segmentation by dividing the transfer process into selective steps using laser irradiation. Instead of treating the entire substrate uniformly, the laser selectively targets specific regions containing bonding protrusions, enabling precise transfer of individual devices or small groups. This segmented approach improves transfer efficiency and precision while reducing overall energy consumption compared to bulk processing methods.
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 method enables efficient transfer and bonding of light emitting devices with reduced height differentials, enhancing the performance and reliability of the light emitting device assemblies by preventing collisions and ensuring proper alignment, thus improving the assembly process.
Implementation Method 1
selectively transferred and bonded onto backplane substrates using laser irradiation and ablation
Data Source
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AI summary
A backplane optionally having stepped horizontal surfaces and optionally embedding metal interconnect structures is provided. First conductive bonding structures are formed on first stepped horizontal surfaces. First light emitting devices on a first transfer substrate are disposed on the first conductive bonding structures, and a first subset of the first light emitting devices is bonded to the first conductive bonding structures. Laser irradiation can be employed to selectively disconnect the first subset of the first light emitting devices from the first transfer substrate while a second subset of the first light emitting devices remains attached to the first transfer substrate. Additional devices on each additional transfer substrate can be bonded to additional conductive bonding structures on the backplane employing the same method provided that the additional devices are not present in positions that would overlap with pre-existing first light emitting devices or devices on the backplane at a bonding position.