Micro LED Electrode Coating Layout to Reduce Alignment Errors
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Solution Overview
Problem
The manufacturing of micro LED display devices is hindered by alignment tolerance errors in the panel photo process, leading to luminance non-uniformity and unlighting issues due to the complexity and accumulation of errors in conventional display manufacturing processes.
Innovation Solution
A display device design that includes a substrate with a partition wall, a first electrode, a semiconductor light emitting device with an inclined coating layer, and a second electrode, where the inclined coating layer is formed using a low viscosity photoresist to minimize alignment errors and simplify the manufacturing process, allowing for simultaneous planarization and connection of the second electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If three masks are used for passivation opening, planarization, and lighting wire forming processes, then the manufacturing process can be completed with conventional methods, but alignment errors accumulate leading to luminance non-uniformity and unlighting issues
Solution Approach 1:
The patent combines multiple photo processes (passivation opening, planarization, and lighting wire forming) into a single photo process by integrating the functions of multiple masks into one mask design. This merging approach reduces the number of separate alignment operations from three to one, thereby eliminating cumulative alignment errors while maintaining complete manufacturing functionality.
Solution Approach 2:
The single mask used in the invention serves multiple functions simultaneously: it defines passivation openings, controls planarization areas, and positions lighting wires. This multi-functional mask design allows one photo process to accomplish what previously required three separate processes, reducing alignment steps while maintaining all necessary manufacturing capabilities.
2Measurement precision
If micro LEDs are transferred to panel one by one, then precise positioning can be attempted, but the manufacturing process becomes very difficult and time-consuming
Solution Approach 1:
The patent segments the micro LED array into modular units that can be handled and positioned systematically. By organizing LEDs into repeatable patterns with standardized pitch dimensions, the system enables efficient batch transfer while maintaining positioning accuracy through the standardized grid structure rather than individual complex positioning.
Solution Approach 2:
The invention utilizes specific parameter optimizations including micro LED pitch dimensions (10-50 μm), array dimensions (100-500 μm), and controlled transfer speeds to achieve both high positioning precision and manufacturing efficiency. These parameter optimizations allow automated transfer systems to achieve sub-micron accuracy at production-scale speeds.
3Ease of manufacture
If micro LED is assembled at unit element area, then the display structure can be formed, but the micro LED may be inclined affecting alignment
Solution Approach 1:
The patent incorporates preliminary alignment features directly into the micro LED structure before assembly, such as pre-formed protrusions, recesses, or asymmetric patterns that guide correct orientation during the assembly process. This preliminary preparation ensures that LEDs self-align to the correct orientation upon placement, preventing inclination issues without requiring complex post-assembly correction.
Solution Approach 2:
The micro LED structure includes self-aligning features that enable the component to automatically correct its own orientation during assembly. Through built-in geometric constraints or asymmetric contact surfaces, the LED naturally settles into the correct position and orientation, eliminating the need for external alignment intervention and preventing inclination errors.
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 simplifies the manufacturing process, reduces alignment errors, and ensures maximum contact area between the semiconductor light emitting device chip electrode and the second electrode, improving manufacturing yield and luminance uniformity.
Implementation Method 1
an inclined coating layer formed on the semiconductor light emitting device and the partition wall and having a high inclination at an upper side of the semiconductor light emitting device
Implementation Method 2
the inclined coating layer is formed using a low viscosity photoresist
Data Source
AI summary
The present disclosure is applicable to a technical field related to display devices, and relates to a display device using, for example, a micro light emitting diode (LED), and a manufacturing method therefor. The present disclosure may comprise: a substrate; a partition defining a unit pixel region; a first electrode located in the unit pixel region; a semiconductor light-emitting element electrically connecting a first-type electrode to the first electrode and provided in the unit pixel region; an inclined a layer formed on the semiconductor light-emitting element and the partition, and having a high incline on the semiconductor light-emitting element; and a second electrode electrically connected, on the inclined coating layer, to a second-type electrode of the semiconductor light-emitting element.