Micro-LED Pixel Layout With Black Subpixels for Defect Repair
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Solution Overview
Problem
Display devices using light emitting diodes (LEDs) face challenges in aligning and positioning millions of micro LEDs, leading to defective sub pixels, which increases manufacturing costs and complexity due to the need for redundant or backup sub pixels and inefficient repair processes.
Innovation Solution
A display device configuration where each pixel includes one first sub pixel, one second sub pixel, one third sub pixel, and one or more black sub pixels, with a color conversion member and black matrix formed according to the position of defective sub pixels, allowing for reduced use of LEDs and simplifying the repair process by using only one type of LED and eliminating the need for additional transferring steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If micro LEDs are transferred to substrate for display device fabrication, then display device with long lifespan and high luminance can be produced, but alignment and placement issues occur resulting in defective sub pixels
Solution Approach 1:
The patent applies preliminary action by pre-defining backup sub pixels in specific positions within pixel units before the transfer process. These backup sub pixels are prepared in advance to replace defective ones, eliminating the need for post-transfer alignment corrections and ensuring high reliability without requiring ultra-precise alignment during manufacturing.
2Reliability
If backup sub pixels are added to replace defective sub pixels, then defective sub pixels can be replaced, but the number of light emitting diodes increases and manufacturing cost increases
Solution Approach 1:
The patent applies local quality by strategically placing backup sub pixels only in specific positions within pixel units where defects are most likely to occur, rather than adding backup sub pixels throughout the entire display. This localized approach ensures reliable defect replacement while minimizing the total number of LEDs required, thus controlling manufacturing costs.
3Illumination intensity
If multiple types of light emitting diodes are used for different sub pixels, then color accuracy is improved, but transferring yield decreases due to complexity
Solution Approach 1:
The patent applies universality by using a single type of blue light emitting diode for all sub pixels within a pixel unit, rather than using different colored LEDs for different sub pixels. This universal approach simplifies the transfer process and increases transferring yield, while color accuracy is maintained through the use of color conversion members that convert the blue light to the required colors.
4Quantity of substance
If color conversion member and black matrix are formed according to defective sub pixel position, then manufacturing cost is reduced, but the manufacturing process complexity increases
Solution Approach 1:
The patent applies local quality by forming color conversion members and black matrices only in specific positions corresponding to backup sub pixels, rather than uniformly across the entire display. This localized formation approach reduces material usage and manufacturing cost, while the systematic positioning strategy keeps the process complexity manageable.
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 configuration reduces the number of LEDs required, minimizes manufacturing costs, simplifies the manufacturing and repair processes, and increases the yield of the transferring process, while maintaining image quality and reducing greenhouse gas emissions.
Implementation Method 1
a light emitting diode disposed in each of the first sub pixel, the second sub pixel, the third sub pixel, and the one or more black sub pixels
Implementation Method 2
a color conversion member disposed on some light emitting diodes among the plurality of light emitting diodes
Implementation Method 3
a light shielding pattern which is disposed on the remaining light emitting diode of the plurality of light emitting diodes
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
A display device can include a substrate including a plurality of pixels; a plurality of light emitting diodes disposed in each of the plurality of pixels; a color conversion member disposed over at least two light emitting diodes among the plurality of light emitting diodes in one pixel among the plurality of pixels; and a light shielding pattern disposed over at least one light emitting diode among the plurality of light emitting diodes in the one pixel for forming a black sub pixel that does not emit light outside of the display device. Also, each of the plurality of pixels includes a first sub pixel, a second sub pixel, a third sub pixel, and one or more black sub pixels.