Bonded Display Substrates for Precise Micro-LED Alignment
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Solution Overview
Problem
Existing display devices with self-light-emitting elements face challenges in precision and reliability due to material vulnerabilities and the complexity of transfer processes, leading to misalignment and decreased yield in large-area displays.
Innovation Solution
A display device and manufacturing method that bond a self-assembly substrate with aligned light-emitting elements to a substrate with thin-film transistors, eliminating the need for transfer stamps and reducing tolerance accumulation, thereby enhancing precision and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If transfer stamps are used to transfer light-emitting elements to substrates, then light-emitting elements can be transferred to the substrate, but positional misalignment occurs and manufacturing precision deteriorates due to tolerance accumulation in large-area displays
Solution Approach 1:
The patent removes the transfer stamp from the manufacturing process entirely. Instead of using a transfer stamp to transfer light-emitting elements to the substrate, the invention grows light-emitting elements directly on the substrate using epitaxial growth, thereby eliminating the source of positional misalignment and tolerance accumulation that occurs with transfer stamps in large-area displays
Solution Approach 2:
The patent performs preliminary preparation of the substrate surface before growing light-emitting elements directly on it. The substrate undergoes surface treatment and pattern formation of electrode structures beforehand, allowing light-emitting elements to be grown in precise predetermined positions directly on the substrate without requiring subsequent transfer operations
2Area of stationary object
If multiple transfer processes are used for large-area displays, then coverage area increases, but tolerance accumulation occurs leading to decreased yield
Solution Approach 1:
The patent segments the large-area substrate into multiple regions and performs epitaxial growth of light-emitting elements in each region separately. This allows precise control of element positions in each segment while maintaining overall large-area coverage, preventing tolerance accumulation that would occur with repeated transfer processes across the entire large area
Solution Approach 2:
The substrate is prepared in advance with region-specific electrode patterns and surface treatments before epitaxial growth. This preliminary segmentation and preparation enables direct growth of light-emitting elements in precise positions across the entire large area in a single integrated process, eliminating the need for multiple transfer operations and the associated yield loss
3Length of moving object
If organic materials are used for light-emitting layers, then display device can be made thinner and flexible, but material vulnerability to moisture and oxygen causes defective pixels
Solution Approach 1:
The patent employs composite material structures for the light-emitting layer, combining organic materials with protective inorganic barrier layers. The organic material provides the desired thin and flexible characteristics, while the inorganic barrier layers prevent moisture and oxygen penetration, thereby maintaining both the thinness advantage and the reliability against pixel defects
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 enables high-precision, large-area display devices with ultra-small light-emitting elements by directly bonding self-assembly substrates to thin-film transistor substrates, improving positional accuracy and reducing production energy while minimizing positional misalignment and yield loss.
Implementation Method 1
a bonding pad disposed between the first substrate and the second substrate, wherein the bonding pad bonds the first substrate and the second substrate to each other
Data Source
AI summary
Disclosed are a display device and a method for manufacturing the same. The display device includes a first substrate including a thin-film transistor. The display device includes a second substrate including a light-emitting element. The display device includes a bonding pad disposed between the first substrate and the second substrate. The bonding pad bonds the first substrate and the second substrate to each other and electrically connects the thin-film transistor of the first substrate and the light-emitting element of the second substrate to each other.