Quantum Dot OLED Pixel Stack for Color-Accurate Mixed-Light Displays
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Solution Overview
Problem
Existing display apparatuses face challenges in achieving high luminous efficiency and color reproducibility, particularly in organic light-emitting diode (OLED) structures with quantum dot color conversion elements and color filters.
Innovation Solution
The display apparatus employs a stacked OLED structure with blue and green light-emitting units, quantum dot color conversion layers, and color filters to enhance luminous efficiency and color reproducibility by mixing blue and green incident light, using thermally activated delayed fluorescence (TADF) dopants and specific phosphorescent dopants, and optimizing color filters for wavelength absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional OLED structure with single-color light-emitting units is used, then the device complexity is low, but the luminous efficiency and color reproducibility are insufficient
Solution Approach 1:
The OLED structure is segmented into multiple light-emitting units (first blue light-emitting unit, green light-emitting unit, second blue light-emitting unit) that emit different wavelengths of light. This segmentation allows each unit to be optimized for specific wavelength emission, improving overall color reproducibility and luminous efficiency while managing complexity through functional division
Solution Approach 2:
The patent employs composite light-emitting structures combining organic light-emitting materials with quantum dot color conversion elements. The composite structure integrates blue OLED units with green phosphor/conversion layers to generate green light, while maintaining blue emission from dedicated blue units, achieving superior color accuracy and luminous efficiency
2Manufacturing precision
If quantum dot color conversion elements are added to improve color reproducibility, then the color accuracy improves, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
Quantum dot color conversion elements are selectively applied only in regions where green light emission is needed, rather than uniformly across the entire OLED structure. This localized application maintains color accuracy where required while simplifying manufacturing in other areas and reducing overall complexity
Solution Approach 2:
The patent introduces charge generation layers as intermediary components between the blue light-emitting units and the green phosphor/conversion elements. These intermediary layers facilitate efficient energy transfer and charge management, enabling precise color control while simplifying the integration process and manufacturing complexity
3Productivity
If blue and green light-emitting units are stacked to provide mixed incident light, then the luminous efficiency improves, but the device complexity increases
Solution Approach 1:
The patent merges blue light-emitting units with green phosphor/conversion elements in a stacked configuration where the green units convert blue light to green, creating a combined blue-green light source. This merging approach improves luminous efficiency by utilizing the high efficiency of blue OLEDs while generating both blue and green wavelengths, reducing the need for separate green OLED units
Solution Approach 2:
The blue light-emitting units serve multiple functions: they provide direct blue emission and simultaneously act as the excitation source for green phosphor/conversion elements. This multi-functionality improves luminous efficiency by utilizing the blue light for dual purposes while reducing the overall device complexity through functional consolidation
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 achieves high luminous efficiency and improved color reproducibility by effectively converting mixed incident light into desired colors, meeting UHD color standards.
Implementation Method 1
including quantum dots for converting the mixed incident light from the OLED structure into light of a predetermined color
Implementation Method 2
first, second, and third color filters disposed on the first, the second, and the third pixels, respectively, to absorb or block light of a predetermined wavelength band
Implementation Method 3
an organic light emitting diode (OLED) structure including at least one blue light-emitting unit configured to emit blue incident light and at least one green light-emitting unit configured to emit green incident light
Data Source
AI summary
A display apparatus includes: an organic light emitting diode (OLED) structure including in which at least one blue light-emitting unit and at least one green light-emitting unit are stacked to provide incident light in which the blue incident light and the green incident light are mixed; a first pixel, a second pixel, and a third pixel disposed on the OLED structure; color conversion layers disposed on at least two of the first, the second, or the third pixels, and including quantum dots for converting the mixed incident from the OLED structure into light of a predetermined color; and first, second, and third color filters disposed on the first, the second, and the third pixels, respectively, to absorb or block light of a predetermined wavelength band, wherein a conversion value of an area of a spectrum in a wavelength region of 380 nanometers to 780 nanometers of the green incident light with respect to a difference between a wavelength at the maximum transmittance of the second color filter and the medial wavelength of the incident green light (Δλ) may be 3.6 or greater and 13 or less.