Full-Color LED Structure Using Stacked Units to Avoid Mass Transfer
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Solution Overview
Problem
The integration of multiple micro-LEDs emitting different colors on the same platform for high-resolution micro-displays is challenging due to differences in manufacturing processes and materials, making it difficult to form full color pixels without the drawbacks of mass transfer.
Innovation Solution
A full color LED structure is developed with a stacking structure of LED units on a substrate, where each unit emits a different color, and a color conversion layer is used to convert one color to another, allowing for integration of multiple sub-pixels on the same platform without mass transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple sub-pixel LEDs emitting different colors are fabricated separately and integrated via mass transfer method, then full color pixels can be formed, but the manufacturing process becomes extremely difficult and nearly impossible for high resolution micro-displays
Solution Approach 1:
The patent merges multiple LED units emitting different colors (blue, green, red) into a single integrated LED structure. The blue LED unit and green LED unit are formed on the same semiconductor layer, with the red LED unit formed by depositing a color conversion layer on the blue LED unit. This combining approach eliminates the need for separate fabrication and mass transfer of multiple sub-pixel LEDs, significantly simplifying the manufacturing process while enabling full color pixel formation.
Solution Approach 2:
The patent implements a nested structure where the red LED unit is formed by depositing a color conversion layer on top of the blue LED unit. The green LED unit is adjacent to the blue LED unit on the same semiconductor layer. This nesting arrangement allows multiple color-emitting units to be integrated in a compact footprint, enabling full color display functionality without requiring separate discrete components for each sub-pixel.
2Adaptability or versatility
If multiple micro-LEDs are integrated on the same platform, then full color images can be displayed, but the manufacturing complexity increases significantly due to different manufacturing processes and materials
Solution Approach 1:
The patent creates a universal platform by forming both blue and green LED units on the same semiconductor layer using the same manufacturing process. This multi-functional approach allows the single semiconductor layer to serve multiple purposes: emitting blue light directly, emitting green light through adjacent structures, and serving as a substrate for the red LED unit formed by color conversion layer deposition. This universality reduces manufacturing complexity while maintaining full color display capability.
Solution Approach 2:
The patent utilizes color conversion through a color conversion layer deposited on the blue LED unit to generate red light emission. This color change mechanism allows a single blue LED structure to serve dual purposes: emitting blue light directly and, when combined with the color conversion layer, emitting red light. This approach simplifies manufacturing by reducing the number of different material systems required while achieving full color display functionality.
3Manufacturing precision
If mass transfer method is used to integrate multiple sub-pixel LEDs, then full color pixels can be formed, but the process becomes nearly impossible for high resolution micro-displays
Solution Approach 1:
The patent performs preliminary actions by forming both blue and green LED units on the same semiconductor layer before final integration. The semiconductor layer is prepared with appropriate doping regions and structures for multiple color emissions. The color conversion layer is deposited in advance on the blue LED unit to create the red LED unit. These preliminary actions eliminate the need for post-fabrication mass transfer operations, making high resolution micro-display manufacturing feasible while maintaining precise pixel formation.
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 enables the formation of full color pixels by integrating sub-pixels emitting different colors, achieving a range of colors through individually driven LED units, while maintaining a flat surface and avoiding the complexities of mass transfer.
Implementation Method 1
a color conversion layer formed on the first LED unit to convert light of the first color to light of a third color different from the first color and the second color
Implementation Method 2
The second doping semiconductor layer of the first LED unit is electrically isolated with the second doping semiconductor layer of the second LED unit by an ion-implanted material formed above the first doping semiconductor layer and the MQW layer
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A LED structure includes a substrate, a first semiconductor layer, a second semiconductor layer, and a color conversion layer. The first semiconductor layer is formed on the substrate, and the first semiconductor layer includes a first LED unit and a second LED unit formed therein. The first LED unit and the second LED unit emit light of a first color. The second semiconductor layer is formed above the first semiconductor layer, and the second semiconductor layer includes a third LED unit formed therein. The third LED unit emits light of a second color different from the first color. The color conversion layer is formed on the first LED unit to convert light of the first color to light of a third color different from the first color and the second color.