Light Conversion Layer Nanocrystals Prevent Color Mixing
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Solution Overview
Problem
The optimization of phosphor materials with quantum dots in wavelength conversion layers for light-emitting devices is challenging, leading to insufficient light absorption and reduced color reproducibility due to inadequate optimization of the primary light source and wavelength conversion layer, causing degradation and color mixing issues in display devices.
Innovation Solution
A light-emitting device with a pair of electrodes, an electroluminescent layer, and a light conversion layer that converts blue emission into other colors using light-emitting nanocrystals, ensuring high luminous efficiency and color reproducibility by preventing color mixing and degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a blue LED and yellow phosphor are combined to obtain white light, then luminous efficiency is improved, but color reproducibility deteriorates due to insufficient red light characteristics
Solution Approach 1:
The patent combines multiple phosphor materials (yellow phosphor and red phosphor) to create a composite wavelength conversion layer that converts blue LED light into white light with improved color reproducibility. This resolves the contradiction by using composite materials to achieve both high luminous efficiency from the blue LED and accurate color reproduction through the added red phosphor component.
Solution Approach 2:
The patent introduces a wavelength conversion layer with phosphor materials as an intermediary between the blue LED and the display elements. This intermediary converts the blue light into white light with balanced spectral characteristics, enabling both high efficiency and good color reproducibility in the final display output.
2Stability of the object's composition
If color filters are used to eliminate characteristics difference among pixels, then pixel uniformity is improved, but transmittance deteriorates leading to increased power consumption
Solution Approach 1:
The patent replaces the traditional color filter system with a wavelength conversion system using phosphor materials. Instead of filtering out unwanted wavelengths (which wastes light and requires higher power), the system converts blue light into white light with the desired spectral characteristics, improving both pixel uniformity and energy efficiency simultaneously.
Solution Approach 2:
The patent changes the fundamental parameter of light manipulation from selective absorption (color filters) to wavelength conversion (phosphor conversion). This parameter change enables high transmittance while achieving uniform pixel characteristics through the phosphor conversion process.
3Duration of action of stationary object
If blue pixels are increased in size to compensate for lower blue receptor sensitivity, then blue pixel lifetime is improved, but display quality deteriorates
Solution Approach 1:
The patent creates a universal white light emission system where all pixels emit white light with consistent characteristics. This eliminates the need for different pixel sizes for different colors, as the wavelength conversion layer ensures uniform performance across all pixels while maintaining appropriate blue light content for accurate color display.
4Measurement precision
If quantum dots are used in wavelength conversion layer, then emission spectrum precision is improved, but light absorption efficiency deteriorates due to insufficient optimization
Solution Approach 1:
The patent optimizes quantum dot parameters including particle size, composition, and shell structure to achieve both narrow emission spectra and high absorption efficiency. By carefully controlling these parameters, the system achieves precise color emission while maintaining efficient energy transfer from the blue LED excitation source.
Solution Approach 2:
The patent uses composite quantum dot structures with core-shell configurations where the core provides narrow emission and the shell enhances absorption and protects the core. This composite structure resolves the contradiction by achieving both spectral precision and absorption efficiency simultaneously.
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 maintains high transmittance and color gamut, inhibiting color mixing and degradation from high-energy rays, thus enhancing the longevity and quality of the image display apparatus.
Implementation Method 1
an electroluminescent layer disposed between the first electrode and the second electrode
Implementation Method 2
a light conversion layer including multiple pixels and converting light that is emitted from the electroluminescent layer and that has a blue emission spectrum into light having a different wavelength, in which the light conversion layer includes pixels of three primary colors of red (R), green (G), and blue (B) and contains a light-emitting nanocrystal having an emission spectrum in any of red (R), green (G), and blue (B)
Data Source
AI summary
It is an object of the present invention to provide an image display apparatus capable of inhibiting or preventing the deterioration of a light conversion layer while high luminous efficiency and high color reproducibility are achieved. The present invention provides a light-emitting device including a pair of electrodes, an electroluminescent layer disposed between a first electrode and a second electrode, a light conversion layer including multiple pixels and converting light that is emitted from the electroluminescent layer and that has a blue emission spectrum into light having a different wavelength. The light conversion layer includes pixels of three primary colors of red (R), green (G), and blue (B) and contains a light-emitting nanocrystal having an emission spectrum in any of red (R), green (G), and blue (B) when light from the electroluminescent layer is incident on at least one of the three primary colors.