Quantum Dot RGB Color Filter for OLED Display
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Solution Overview
Problem
Existing organic light-emitting display devices face challenges in achieving wide RGB color gamut values and minimizing light source loss due to interference among red, green, and blue light, as well as inefficiencies in film formation processes.
Innovation Solution
Incorporating zincblende quantum dots in an RGB color filter layer within the organic light-emitting display device, which absorbs and emits light in specific wavelength ranges to eliminate interference and reduce light source loss by integrating quantum dots directly into the color filter layer rather than using a backlight or functional film.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If quantum dots are applied to a backlight to compensate for luminance decrease, then luminous efficacy is improved, but device complexity increases and manufacturing process becomes more complex
Solution Approach 1:
The patent combines the quantum dot layer with the color filter layer into a single integrated structure. The color filter layer serves dual functions: filtering unwanted wavelengths and containing the quantum dots for wavelength conversion. This merging eliminates the need for separate quantum dot films and reduces manufacturing steps while maintaining improved luminous efficacy.
Solution Approach 2:
The color filter layer is designed to perform multiple functions simultaneously: it acts as both a traditional color filter and a quantum dot host layer. This multi-functionality reduces the overall device complexity by eliminating redundant components while achieving both color purification and wavelength conversion for improved luminous efficacy.
2Reliability
If a resin-based photoelectric conversion layer is used, then color reproducibility is improved, but transmittance decreases resulting in backlight light source energy loss
Solution Approach 1:
The patent extracts the quantum dots from the resin-based photoelectric conversion layer and integrates them directly into the color filter layer. This extraction eliminates the resin layer that caused energy loss (reducing transmittance from ~90% to near-100%), while the quantum dots remain in place to maintain color reproducibility through precise wavelength conversion.
Solution Approach 2:
The quantum dots are selectively positioned within the color filter layer at specific locations where wavelength conversion is needed. This localized placement allows the quantum dots to maintain color reproducibility while the surrounding color filter material provides high transmittance, minimizing energy loss in the backlight path.
3Device complexity
If white OLED is used with broad yellow peak spectrum, then device complexity is reduced, but cross talk between green and red light occurs decreasing color reproducibility
Solution Approach 1:
The patent segments the broad yellow peak spectrum of the white OLED into distinct wavelength components using quantum dots with specific bandgaps. The quantum dots absorb the broad spectrum and emit narrow-band green and red light, eliminating cross-talk. This segmentation maintains simple device structure while achieving precise color reproduction through spectral decomposition.
4Ease of manufacture
If quantum dots are mixed with RGB color filter layer, then manufacturing process is simplified and device is slimmed, but achieving wide RGB color gamut while minimizing light source loss becomes challenging
Solution Approach 1:
The patent optimizes the bandgap parameters of the quantum dots to match the spectral requirements for wide RGB color gamut (BT.2020 standard). By carefully selecting quantum dot materials and sizes to achieve specific emission wavelengths and narrow FWHM, the integrated color filter layer achieves both simplified manufacturing and high luminous efficacy, as the quantum dots efficiently convert the blue backlight into pure red, green, and blue light with minimal loss.
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 the achievement of wide RGB color gamut values up to 100% based on the BT.2020 color standard, reduces light source loss, and simplifies the manufacturing process by omitting film formation, resulting in a slimmer device with improved color reproduction and luminous efficacy.
Implementation Method 1
quantum dots that absorb light incident from the organic light emitting element and emit a specific wavelength band of light
Implementation Method 2
semiconductor nanocrystals are very small, thereby having a large surface area per unit volume and exhibiting a quantum confinement effect. Accordingly, semiconductor nanocrystals have physicochemical properties different from those of a semiconductor material itself. Quantum dots absorb light from an excitation source to enter an energy excitation state, and emit energy corresponding to the energy band gap of the quantum dots.
Data Source
AI summary
An organic light-emitting display device includes quantum dots and an RGB color filter layer having quantum dots and thus is capable of removing 100% of interference among red, green, and blue color filters.