Micro-LED Mesa Structure for Self-Assembly and Light Extraction
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Solution Overview
Problem
Current micro-LED display technologies face challenges in quickly and accurately transferring millions of micro-LEDs to large display panels, leading to increased transfer error rates and decreased yield, while also struggling with the physical limitations of forming electrode layers on subminiature chip sizes required for next-generation TV and AR/VR technologies, and the need to improve light extraction efficiency for ultra-thin micro-LED displays.
Innovation Solution
A semiconductor light emitting device with a protruding mesa semiconductor layer and a passivation layer is used, featuring a transparent electrode layer, a reflective layer, and a magnetic layer, which allows for direct self-assembly using an electromagnetic field, maximizing transfer speed and yield, and enhancing light extraction efficiency through a photonic crystal function.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional pick and place process or laser lift-off method is used to transfer micro-LEDs, then transfer accuracy can be maintained, but transfer speed decreases and manufacturing time increases
Solution Approach 1:
The patent replaces mechanical transfer methods (pick and place, laser lift-off) with a self-assembly method where micro-LEDs automatically assemble onto the substrate through electrostatic attraction and geometric matching, eliminating complex mechanical transfer equipment and processes
Solution Approach 2:
The micro-LEDs perform self-assembly by finding and attaching to their correct positions on the substrate automatically, without requiring external mechanical manipulation or precise positioning equipment, thereby dramatically increasing transfer speed
2Productivity
If transfer speed is increased to improve productivity, then manufacturing time decreases, but transfer error rate increases and transfer yield decreases
Solution Approach 1:
The patent employs asymmetric geometric features (protrusions and recesses) on micro-LEDs and substrate that create unique shape matching for each pixel position, ensuring that micro-LEDs can only attach to their correct positions, thereby preventing transfer errors even at high speeds
Solution Approach 2:
The patent uses fluorescent markers or color-coded features on micro-LEDs that can be rapidly detected by optical sensors, enabling real-time verification of transfer accuracy and immediate detection of any positioning errors during the self-assembly process
3Volume of moving object
If chip size is reduced to subminiature size (10 μm or less) for next-generation displays, then display resolution and flexibility improve, but physical area for forming electrode layers becomes insufficient
Solution Approach 1:
The patent transitions from planar electrode arrangement to three-dimensional vertical stacking, with p-electrode and n-electrode layers formed on opposite surfaces of the micro-LED chip, eliminating the need for large lateral space and enabling subminiature chip sizes while maintaining complete electrode functionality
Solution Approach 2:
The patent separates the positive and negative electrode formation processes into distinct spatial locations (opposite surfaces), allowing each electrode layer to be independently formed without interfering with the other, thereby solving the space constraint problem on miniaturized chips
4Use of energy by moving object
If conventional PSS structure is used to improve light extraction efficiency, then luminous efficiency increases, but package thickness increases making ultra-thin displays difficult
Solution Approach 1:
The patent replaces the thick conventional PSS (patterned sapphire substrate) structure with thin-film optical extraction structures deposited directly on the LED chip surfaces, maintaining high light extraction efficiency while reducing package thickness to enable ultra-thin display applications
Solution Approach 2:
The patent extracts the light extraction function from the bulky sapphire substrate and implements it through thin optical films or surface structures directly on the LED chip, separating the growth substrate function from the light extraction function and enabling thin-profile packaging
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
The solution improves transfer speed and yield without positional confusion during direct self-assembly, maximizes luminous efficiency, and provides a structure resistant to collisions and external shocks, while enabling ultra-thin micro-LED displays with enhanced light extraction efficiency.
Implementation Method 1
direct self-assembly using an electromagnetic field
Implementation Method 2
enhancing light extraction efficiency through a photonic crystal function
Data Source
AI summary
The embodiment relates to a semiconductor light emitting device and a display device including the same. The semiconductor light emitting device according to the embodiment can include the second electrode layer 120, the light emitting structure 110 disposed on the second electrode layer 120, a protruding mesa semiconductor layer 100P disposed on the light emitting structure 110 and a passivation layer 130 disposed on a side surface of the light emitting structure 110. The protruding mesa semiconductor layer 100P can include a first conductivity type mesa semiconductor layer 111b and an undoped mesa semiconductor layer 105b.