Micro LED Contact Hole Structure for Transfer Misalignment Tolerance
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Solution Overview
Problem
The existing organic electronic light emitting display devices face challenges in manufacturing large area displays due to limitations in the process using metal shadow masks and high manufacturing costs, while also experiencing reduced luminance and color purity due to light absorption by color filters.
Innovation Solution
A micro LED display device is designed with a substrate having thin film transistors, micro LEDs with a protecting film and contact holes, and insulating layers with specific contact holes to allow for external signal transmission, enabling a larger tolerance for transfer errors and preventing lighting malfunctions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a metal shadow mask is used to deposit organic light emitting layer, then manufacturing precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts and removes the metal shadow mask from the manufacturing process entirely. Instead of using a shadow mask for patterning, the invention employs a self-aligned approach where the pixel electrode pattern itself defines the emission area, eliminating the need for separate shadow mask fabrication and alignment steps.
Solution Approach 2:
The pixel electrode serves multiple functions: it acts as both the electrical contact and the patterning element that defines the light emission area. This multi-functionality eliminates the need for a separate shadow mask component, simplifying the overall manufacturing process.
2Manufacturing precision
If a metal shadow mask is used for high resolution display, then manufacturing precision is improved, but ease of manufacture deteriorates
Solution Approach 1:
The shadow mask is completely removed from the manufacturing process. High resolution is achieved through precise photolithography patterning of the pixel electrode and hole injection layer, which can be more easily scaled to large areas compared to shadow mask techniques.
Solution Approach 2:
The invention transitions from a three-dimensional shadow mask structure to a planar, self-aligned patterning approach using thin film layers. This dimensional simplification enables easier manufacturing while maintaining high resolution through precise layer alignment.
3Ease of manufacture
If a white light emitting element with color filter is used, then ease of manufacture is improved, but luminance and color purity deteriorate
Solution Approach 1:
Instead of using a white light source with color filters, the invention employs red, green, and blue light emitting elements with different emission spectra. Each element is optimized for its specific color range, eliminating light absorption losses and improving overall luminance and color purity.
Solution Approach 2:
The patent uses composite organic light emitting materials with different emission characteristics (red, green, blue) to create the display. This composite approach replaces the white light + color filter system, improving luminance by avoiding filter absorption while maintaining manufacturing simplicity.
4Ease of manufacture
If a white light emitting element with color filter is used, then ease of manufacture is improved, but color purity deteriorates
Solution Approach 1:
The invention uses organic light emitting materials with narrow emission spectra tailored to specific color ranges (red, green, blue). This local optimization of emission characteristics for each color eliminates the need for broad-spectrum white light and color filters, achieving high color purity while maintaining manufacturing simplicity.
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 micro LED display device achieves a longer lifespan, lower power consumption, and easier implementation of flexible displays, while increasing the allowable tolerance for transfer errors and preventing lighting malfunctions caused by misalignment.
Implementation Method 1
a plurality of micro LEDs provided on the upper surface of the substrate, the micro LEDs each having a protecting film provided with a first contact hole to expose a portion thereof to the outside
Data Source
AI summary
The present disclosure relates to a micro light emitting diode (LED) display device including a substrate having a plurality of thin film transistors thereon; a plurality of micro light emitting devices (LEDs) on an upper surface of the substrate, the micro LEDs each having a protecting film provided with a first contact hole to expose a portion of an upper surface of a corresponding micro LED; at least one insulating layer covering the micro LED, the insulating layer provided with a second contact hole to expose a portion of the upper surface of the corresponding micro LED; and a connection electrode in the first contact hole and the second contact hole configured to transfer signals to the micro LED, wherein the first contact hole is larger than the second contact hole.