Quantum Dot Color Conversion Layer for Micro-LED Subpixel Alignment
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Solution Overview
Problem
The challenge in high-resolution, high-ppi augmented reality (AR) displays is accurately placing different color micro-LEDs (e.g., red, green, and blue) onto adjacent subpixels with tight tolerances, which is difficult due to their small size and the need for precise alignment.
Innovation Solution
Utilizing photonically pumped quantum dots coupled with UV or blue emitting LEDs, where the quantum dots are positioned in vias over the LEDs to convert photons into various colors, allowing for improved alignment and uniformity across the display backplane by using a monochrome LED array to manufacture and align the quantum dots in subpixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If different color micro-LEDs are placed onto adjacent subpixels, then color display capability is improved, but alignment precision deteriorates due to small size and tight tolerances
Solution Approach 1:
The display is segmented into subpixels, with each subpixel containing a monochrome micro-LED and associated quantum dot materials. This segmentation allows each micro-LED to be manufactured with consistent monochrome characteristics, while the quantum dot layer provides the color conversion function, thereby avoiding the alignment difficulties of placing different colored micro-LEDs directly onto subpixels.
Solution Approach 2:
Quantum dot materials serve as an intermediary between the monochrome micro-LEDs and the final color output. The quantum dots convert the monochrome light from the LEDs into various colors through photoluminescence, eliminating the need for precise placement of different colored micro-LEDs and simplifying the manufacturing alignment requirements.
2Ease of operation
If monochrome LED array with quantum dots is used, then alignment ease is improved, but device complexity increases due to additional quantum dot deposition and curing steps
Solution Approach 1:
The quantum dot deposition, curing, and color conversion functions are merged into a single integrated layer structure. The photocurable polymer material and quantum dots are combined in an ink formulation that can be deposited in a single step, and the same UV light that cures the polymer also activates the quantum dots, thereby reducing process complexity despite the additional functionality.
Solution Approach 2:
The manufacturing process utilizes parameter changes in the quantum dot ink formulation, specifically using photocurable polymer materials that transition from liquid to solid state upon UV exposure. This parameter change enables the quantum dot layer to be formed and stabilized in a single deposition and curing cycle, simplifying the overall manufacturing process while maintaining alignment ease.
3Power
If photocurable quantum dot ink is used with UV or blue LED illumination, then color conversion efficiency is improved, but energy consumption increases due to additional illumination steps
Solution Approach 1:
The UV or blue LEDs serve multiple functions: they act as the primary light source for the display and simultaneously serve as the illumination source for curing the photocurable quantum dot ink. This multi-functionality eliminates the need for separate curing light sources, thereby reducing overall energy consumption while maintaining high color conversion efficiency.
Solution Approach 2:
The curing process and color conversion process are continuous and simultaneous operations. The UV or blue light continuously illuminates the quantum dot ink during deposition and curing, ensuring that the photocurable polymer hardens while the quantum dots are activated for color conversion, thereby maximizing energy utilization efficiency and minimizing total energy consumption.
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 high-efficiency, uniform color generation across AR displays by simplifying the alignment process and ensuring tight tolerances are met, even with micro-LEDs smaller than 10 microns, enhancing display quality.
Implementation Method 1
the quantum dots are configured to absorb the incident photons from the corresponding one of the plurality of light emitting diodes and to generate converted photons having a longer peak wavelength than a peak wavelength of the incident photons
Implementation Method 2
illuminating the first photocurable quantum dot ink with ultraviolet radiation or blue light from first light emitting diodes of an array of light emitting diodes to crosslink the first photocurable polymer material in the first vias
Data Source
AI summary
A method of forming a light emitting device includes providing a free standing support containing a matrix material including first and second vias, depositing in the first vias a first photocurable quantum dot ink including first quantum dots suspended in a first photocurable polymer, illuminating the first photocurable quantum dot ink with ultraviolet radiation or blue light from first LEDs of an array of LEDs to crosslink the first photocurable polymer material in the first vias, depositing in the second vias a second photocurable quantum dot ink comprising second quantum dots suspended in a second photocurable polymer material, illuminating the second photocurable quantum dot ink with ultraviolet radiation or blue light from second LEDs of the array of LEDs to crosslink the second photocurable polymer material in the second vias, and attaching the free standing support to the array of LEDs after the illuminating.