Vertical Micro LED Alignment via Substrate Through Holes
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Solution Overview
Problem
Micro LEDs face challenges in achieving stable vertical alignment due to size constraints, leading to reduced light efficiency and integration density, as well as difficulties in connecting electrodes, especially when aligned horizontally, which limits their application in high-resolution displays.
Innovation Solution
A vertical alignment method involving a substrate with through holes, where micro LEDs are suspended and aligned by a pressure difference, allowing them to be inserted and fixed vertically, with a stopper plate ensuring they remain in place, and electrodes are connected to the conductive layers on the substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If micro LEDs are aligned horizontally on a substrate, then the alignment process is simpler, but light efficiency is reduced and the area occupied by each LED increases
Solution Approach 1:
The patent transitions from horizontal alignment to vertical alignment by changing the spatial dimension of LED placement. Through holes are formed in the substrate extending in the thickness direction, and micro LEDs are inserted vertically into these holes. This dimensional change allows the light emission direction to face the front surface directly, improving light efficiency while reducing the area occupied by each LED on the substrate surface.
2Ease of manufacture
If micro LEDs are aligned horizontally, then manufacturing is easier, but the degree of integration is reduced
Solution Approach 1:
By aligning micro LEDs vertically in the thickness direction of the substrate rather than horizontally on the surface, the patent increases the number of LEDs that can be packed into a given area. The vertical arrangement allows for higher integration density as LEDs are stacked through the substrate thickness, effectively increasing the quantity of functional elements within the same footprint area.
3Device complexity
If micro LEDs are self-aligned using dielectrophoretic force, then no additional alignment structure is needed, but accurate alignment cannot be achieved and the aligned state is difficult to maintain
Solution Approach 1:
The patent introduces through holes as an intermediary structural element that facilitates precise alignment. The micro LEDs are inserted into these pre-formed through holes, which act as mechanical guides ensuring accurate positioning. This intermediary structure replaces the insufficient dielectrophoretic self-alignment method, providing both alignment accuracy and stable maintenance of the aligned state through physical constraint.
4Illumination intensity
If micro LEDs are aligned vertically with greater vertical width than lateral width, then light efficiency improves, but alignment difficulty increases due to size constraints
Solution Approach 1:
The patent performs preliminary actions by pre-forming through holes in the substrate before inserting the micro LEDs. These through holes are created with dimensions and positions predetermined for optimal LED alignment. This preliminary preparation simplifies the subsequent LED insertion process, making vertical alignment of vertically-oriented LEDs more manageable despite their size constraints.
Solution Approach 2:
The through holes serve as an intermediary that facilitates the alignment of vertically-oriented micro LEDs. By providing a physical guide structure, the through holes reduce the alignment difficulty associated with the small size and vertical orientation of the LEDs, enabling precise positioning without requiring complex alignment procedures.
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 stable vertical alignment and efficient light emission, improving light efficiency and integration density, making micro LEDs suitable for high-resolution displays and other applications.
Implementation Method 1
locating micro LEDs to be aligned on the substrate in a state of being included in a suspension which provides buoyancy
Implementation Method 2
generating a pressure difference between an upper side and a lower side of the substrate and moving the suspension in a downward direction through the through holes of the substrate
Data Source
AI summary
Disclosed is a vertical alignment method of a micro light emitting diode (LED), which is capable of vertically aligning vertical type micro LEDs each having a nano size or micro size and stably maintaining an aligned state on a structural basis. The method includes preparing a substrate provided with a plurality of through holes formed in a thickness direction, locating micro LEDs to be aligned on the substrate in a state of being included in a suspension which provides buoyancy, and generating a pressure difference between an upper side and a lower side of the substrate and moving the suspension in a downward direction through the through holes of the substrate to induce the micro LEDs included in the suspension to be aligned in an upright state by being at least partially inserted into the through holes.