Micro LED Sub-Pixel Layout With Segmented Emitting Regions
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Solution Overview
Problem
The challenge in micro LED display technology is aligning electrodes with pads on the backplane, leading to low production yield and image quality due to defective micro LEDs in sub-pixel regions, as conventional solutions result in overly large sub-pixel regions and limited resolution.
Innovation Solution
A micro light emitting diode chip design with multiple second electrodes and light-emitting regions, where each sub-pixel region has a larger electrode bonding area, allowing for independent control of light-emitting layers and improved bonding success, reducing defect pixels and enhancing production yield and image quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple bonding layers and micro LEDs are disposed in each sub-pixel region with redundant repairing bond pads, then the production yield is improved by allowing re-bonding of defective micro LEDs, but the sub-pixel region becomes overly large and the overall resolution is limited
Solution Approach 1:
The micro LED chip is divided into multiple independent light-emitting regions (first, second, and third light-emitting regions) with separate bonding electrodes. This segmentation allows individual regions to function independently, so that if one region or its bonding fails, other regions can still operate, improving yield without requiring larger sub-pixel regions for redundant bonding attempts.
Solution Approach 2:
Instead of adding redundant bonding pads in the planar dimension (which increases sub-pixel area), the invention adds functional redundancy in the vertical/dimensional sense by creating multiple light-emitting regions within the same footprint. This allows yield improvement without increasing the area occupied by each sub-pixel region.
2Ease of manufacture
If the electrodes of micro LED are bonded to pads on the backplane, then the display panel can be assembled, but alignment difficulty reduces production yield and deteriorates image quality
Solution Approach 1:
The micro LED chip is divided into multiple light-emitting regions with separate bonding electrodes. This segmentation provides multiple bonding interfaces, increasing the probability that at least some electrodes will align correctly with the pads during the bonding process, thereby compensating for alignment difficulties and maintaining manufacturing precision.
Solution Approach 2:
The invention changes the bonding configuration from a single bonding interface to multiple bonding interfaces (first, second, and third bonding electrodes). This parameter change increases the tolerance to alignment errors, as the bonding process can succeed even if not all electrodes align perfectly, thus improving both ease of manufacture and maintaining manufacturing precision.
3Device complexity
If conventional bonding methods are used with single light-emitting regions, then the structure is simple, but the bonding success probability is low and defect pixels increase
Solution Approach 1:
The micro LED chip is divided into multiple light-emitting regions (first, second, and third light-emitting regions) with separate bonding electrodes. This segmentation provides multiple independent bonding opportunities, significantly increasing the probability that at least some bonds will succeed even if others fail, thereby improving reliability without excessive complexity.
Solution Approach 2:
The multiple light-emitting regions and separate bonding electrodes serve as a cushioning mechanism against bonding failures. If some bonding attempts fail or defects occur, the other regions provide a backup that ensures the pixel can still function, cushioning against the harmful effects of defects and improving overall reliability.
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 design improves the bonding yield and image quality by ensuring at least one second electrode is successfully bonded, allowing for independent control of light-emitting regions, reducing defect pixels, and increasing the overall resolution of the display panel.
Implementation Method 1
Each of the light-emitting regions is defined by the first electrode and one of the second electrodes to emit light
Data Source
AI summary
A micro light emitting diode display panel includes a backplane and a plurality of micro light emitting diode chips. The backplane includes a plurality first electrode lines and a plurality of second electrode lines. The first electrode lines and the second electrode lines define a plurality of sub-pixel regions arranged in an array form. The micro light emitting diode chips are disposed on the backplane and respectively located in the sub-pixel regions. Each of the micro light emitting diode chips has a first electrode, a plurality of second electrodes and a plurality of light-emitting regions. The first electrode is boned to one of the first electrode lines, and the second electrodes are boned to one of the second met lines. In a defect sub-pixel region, the electrical connection between one of the second electrodes and the corresponding one of the second electrode lines is cut to isolate.