Micro-LED Recess Color Conversion for Precise Multi-Color Alignment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The fabrication of micro-LED displays faces challenges in integrating multiple colors onto a single panel due to stringent placement accuracy requirements and the need for separate processes for different color emission, which limits throughput and yield, and existing color conversion methods suffer from alignment, scalability, and resolution issues.
Innovation Solution
A method involving the selective deposition of photo-curable fluids containing color conversion agents over recesses on a monochrome micro-LED array, where the micro-LEDs are activated to cure the fluid in situ, forming color conversion layers, allowing for precise alignment and high-throughput production of multi-color displays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If pick-and-place step is used to transfer micro-LED devices from donor substrates to destination substrate, then multiple colors of micro-LED devices can be integrated onto a single panel, but placement accuracy requirements (less than 1 um) limit throughput and final yield
Solution Approach 1:
The patent merges the color conversion layer formation process with the micro-LED integration process by using the same recess structures and curing mechanisms for both purposes, eliminating the need for separate pick-and-place operations while maintaining precise color alignment with each micro-LED pixel
Solution Approach 2:
The patent introduces a photo-curable fluid as an intermediary medium that contains color conversion agents. This fluid is dispensed into recesses and cured by UV light to form color conversion layers, serving as a mediator between the micro-LED light sources and the final color output, thereby eliminating complex mechanical transfer processes
2Adaptability or versatility
If separate processes are used for fabricating micro-LEDs with different color emission on different substrates, then each color can be optimized independently, but integration requires modification of LED structure or fabrication process with sacrificial layers
Solution Approach 1:
The patent creates a universal fabrication process where monochrome micro-LEDs can serve multiple color functions through the color conversion layer. The same micro-LED structure and fabrication process can produce different colors by simply changing the color conversion agent in the photo-curable fluid, eliminating the need for separate fabrication processes for each color
Solution Approach 2:
The patent applies local quality by placing different color conversion agents in different recesses corresponding to different micro-LED pixels. Each recess receives a specific color conversion agent tailored to the emission characteristics of its underlying micro-LED, enabling precise local color control without affecting other pixels
3Manufacturing precision
If color conversion agents are selectively deposited using high-resolution shadow masks or controllable inkjet printing, then color conversion can be achieved, but alignment, scalability, and resolution issues arise
Solution Approach 1:
The patent performs preliminary action by forming recesses in the substrate before dispensing the color conversion agents. These pre-formed recesses act as precise alignment guides that automatically position the color conversion layers correctly over each micro-LED pixel, eliminating the need for complex real-time alignment systems during deposition
Solution Approach 2:
The patent replaces complex mechanical alignment systems (such as high-resolution shadow masks or controllable inkjet positioning systems) with a simpler UV curing mechanism. The photo-curable fluid is dispensed into pre-formed recesses and cured by UV light from the micro-LEDs themselves, substituting mechanical precision requirements with optical curing precision
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 the efficient and accurate formation of color conversion layers over micro-LEDs, enhancing yield and throughput, and facilitating the production of large-format and flexible multi-color micro-LED displays with improved alignment accuracy.
Implementation Method 1
A light emitting diode (LED) panel uses an array of LEDs
Implementation Method 2
A first plurality of light emitting diodes in the array of light emitting diodes are activated to illuminate and cure the first photo-curable fluid
Implementation Method 3
The color conversion agents can convert this short wavelength light into longer wavelength light, e.g., red or green light for red or green pixels
Data Source
AI summary
A method of fabricating a multi-color display includes dispensing a photo-curable fluid over a display having an array of light emitting diodes (micro-LEDs) disposed below a cover layer. The cover has an outer surface with a plurality of recesses, and the photo-curable fluid fills the recesses. The photo-curable fluid includes a color conversion agent. A plurality of LEDs in the array are activated to illuminate and cure the photo-curable fluid to form a color conversion layer in the recesses over the activated LEDs. This layer will convert light from these LEDs to light of a first color. An uncured remainder of the photo-curable fluid is removed. Then the process is repeated with a different photo-curable fluid having a different color conversion agent and a different plurality of LEDs. This forms a second color conversion layer in different plurality of recesses to convert light from these LEDs to light of a second color.