Semiconductor Nanocrystal Color Conversion Layers for Display Devices
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Solution Overview
Problem
Display devices with individual emitting systems face challenges in large-scale production due to complex pixel formation with different materials and suffer from energy loss and luminance deterioration when using color filters, which affect color purity and reproducibility.
Innovation Solution
A display device structure incorporating multiple light-emitting element packages with semiconductor nanocrystals in color conversion layers and a transmitting layer, formed using an electrophoresis method, which simplifies the manufacturing process and enhances color purity and luminous efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a display device uses a color filter to pass light from a light source, then it can be easily produced in larger areas, but light is absorbed by the color filter causing energy loss and deterioration of luminance and color purity
Solution Approach 1:
The patent changes the material parameter from conventional color filters to semiconductor nanocrystals, which have different optical properties. The nanocrystals convert light wavelengths through quantum confinement effects rather than absorbing light, thereby maintaining high luminous efficiency and color purity while enabling large-area production.
Solution Approach 2:
The patent uses composite structures including semiconductor nanocrystals embedded in a matrix material to form color conversion layers. This composite approach combines the light-conversion efficiency of nanocrystals with the structural properties of the matrix, achieving both high energy efficiency and manufacturability in large areas.
2Area of stationary object
If a display device uses a color filter to pass light from a light source, then it can be easily produced in larger areas, but deterioration of luminance and color purity occurs since the final emitted light has a wide full width at half maximum
Solution Approach 1:
The patent changes the optical parameter approach by using semiconductor nanocrystals with size-dependent bandgap properties. By controlling the size of nanocrystals, the emission wavelength can be precisely tuned, achieving narrow full width at half maximum and high color purity that cannot be achieved with conventional color filters.
3Manufacturing precision
If a display device uses an individual emitting system with pixels formed by different materials, then it achieves high color purity and excellent image quality, but it has huge processing difficulty and is difficult to be formed in large scale
Solution Approach 1:
The patent merges the color generation function into a single light-emitting layer using semiconductor nanocrystals that can emit different colors based on their size, rather than using separate pixels with different materials. This consolidation simplifies the manufacturing process while maintaining high color purity through quantum confinement effects.
Solution Approach 2:
The semiconductor nanocrystal layer serves multiple functions: it acts as both the light-emitting layer and the color-filtering layer simultaneously. The nanocrystals can be tuned to emit different wavelengths, providing both light emission and color selection in a single component, thereby reducing device complexity.
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 high color purity and reproducibility with reduced manufacturing time and cost, while maintaining high luminous efficiency by using semiconductor nanocrystals in multiple layers to convert and transmit light effectively.
Implementation Method 1
formed using an electrophoresis method
Implementation Method 2
a first color conversion layer, a second color conversion layer, and a transmitting layer disposed on the protective layer, where each of the first color conversion layer, the second color conversion layer, and the transmitting layer is overlapped with one of the plurality of light-emitting element packages
Data Source
AI summary
A method of manufacturing a display device includes preparing a plurality of light-emitting element packages on a substrate, preparing a first solution including first semiconductor nanocrystals, applying a voltage to a part of the plurality of light-emitting element packages to transport the first semiconductor nanocrystals to a region overlapped with the part of the plurality of light-emitting element packages, and forming a first color conversion layer with the first semiconductor nanocrystals.