Emissive Display Fabrication via Suspension Embedding
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Solution Overview
Problem
The conventional pick-and-place process for transferring microfabricated LED structures to large substrates is inefficient, taking several hours to complete and risking damage to the package substrate and LEDs.
Innovation Solution
A method using a package substrate with wells and LEDs designed according to the Bernoulli's principle, where the substrate and LEDs have electrode regions at different heights, allowing for mass transfer without damage by embedding LEDs into wells using a suspension flowing at different velocities, ensuring electrical connection and efficient assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a pick-and-place process is used to transfer LED microstructures to large substrates, then the transfer can be completed, but the process takes several hours and is inefficient
Solution Approach 1:
The invention divides the large substrate into multiple smaller substrates, each capable of receiving multiple LED microstructures simultaneously. This segmentation allows parallel processing of multiple LEDs across multiple substrates, dramatically increasing transfer efficiency from sequential pick-and-place to batch processing.
Solution Approach 2:
The invention combines multiple transfer operations into a single simultaneous process. Multiple LED microstructures are transferred to multiple substrates at the same time using a unified transfer mechanism, merging what would otherwise be separate sequential operations into one efficient batch process.
2Productivity
If conventional transfer methods are used, then LEDs can be transferred, but the package substrate and LEDs may be damaged
Solution Approach 1:
The invention uses a suspension liquid with density matching the LED microstructures to provide buoyant support during transfer. This counteracts gravity and prevents mechanical stress on the fragile LEDs and substrates, enabling damage-free handling and transfer of millions of LED elements simultaneously.
Solution Approach 2:
The suspension liquid acts as an intermediary medium between the LED microstructures and the transfer mechanism. Instead of direct mechanical contact that could cause damage, the suspension enables gentle, controlled transfer through buoyancy and fluid dynamics, protecting both LEDs and substrates from mechanical stress.
3Ease of manufacture
If electrode regions are placed close together on the substrate, then electrical connection is achieved, but short-circuiting may occur
Solution Approach 1:
The invention resolves the electrode spacing problem by using three-dimensional well structures. Electrode regions are positioned at different vertical heights within the wells, allowing electrical connection while maintaining horizontal separation. This dimensional separation prevents short-circuits while ensuring proper electrical connectivity.
Solution Approach 2:
The invention nests electrode regions within three-dimensional well structures, where first electrode regions and second electrode regions are positioned at different heights within the same vertical space. This nested arrangement allows compact integration while maintaining electrical isolation through vertical separation.
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 rapid and damage-free assembly of emissive displays by leveraging the Bernoulli principle for efficient embedding of LEDs into wells, enhancing the transfer process and preventing short-circuiting.
Implementation Method 1
horizontally jetting the suspension and flowing the suspension across the plane and the curved surface of each of the plurality of light-emitting diodes at different velocities, the suspension respectively embeds the plurality of light-emitting diodes into the plurality of wells according to the different velocities
Implementation Method 2
a density of the package substrate is larger than a density of a suspension, and the package substrate sinks in the suspension; and the plurality of light-emitting diodes sinks in the suspension
Data Source
AI summary
In a method for fabricating an emissive display, a package substrate with a top thereof having a plurality of wells is firstly provided. The well has a first electrode region and a second electrode region at different heights. The package substrate sinks in a suspension. Then, a plurality of light-emitting diodes sinks in the suspension. The light-emitting diode has a plane and a curved surface. Finally, the suspension horizontally jets such that the suspension flows across the plane and the curved surface of the light-emitting diode at different velocities. According to the different velocities, the suspension respectively embeds all the light-emitting diodes into all the wells. Each of the plurality of light-emitting diodes are respectively electrically connected to the first electrode region and the second electrode region of a corresponding one of the plurality of wells, thereby forming an emissive display.