Hybrid QLED-OLED Display Sub-pixel Architecture
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Solution Overview
Problem
Display devices using LCDs and OLEDs face issues such as wasted light, reduced luminance, energy inefficiency, and color shifting due to color filtering and differential aging of blue OLEDs, leading to burn-in and poor viewing angles.
Innovation Solution
Implementing QLEDs as light sources in red and green sub-pixels and OLEDs in blue sub-pixels, with quantum dot films and organic phosphor layers to achieve wider color gamut, improved efficiency, and longer operational lifetime, while eliminating the need for microcavities and extra optical structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If blue QLEDs are used in blue sub-pixels to achieve narrow FWHM and wide color gamut, then color accuracy is improved, but operational lifetime and efficiency are reduced compared to red and green QLEDs
Solution Approach 1:
The display device segments the light source technology by sub-pixel color: blue sub-pixels use OLED technology while red and green sub-pixels use QLED technology. This segmentation allows each sub-pixel type to utilize the most suitable material system, thereby achieving both narrow FWHM for blue (via OLED) and long operational lifetime for blue (via OLED), while maintaining color accuracy through the combination with QLED-based red and green sub-pixels.
2Duration of action of stationary object
If RGB OLEDs are used with blue OLEDs turned off when no blue light is needed to extend lifetime, then operational lifetime is improved, but differential aging causes color shifting and burn-in
Solution Approach 1:
The patent segments the light source technology by sub-pixel color, using OLED for blue sub-pixels and QLED for red and green sub-pixels. This eliminates the differential aging problem because all sub-pixels use the same QLED technology platform, ensuring uniform aging characteristics and color stability across the display over time.
3Illumination intensity
If microcavities are used in RGB OLED sub-pixels to enhance forward emission and increase color purity, then luminance is improved, but viewing angle is reduced with dramatic color shift at off-normal angles
Solution Approach 1:
The patent extracts and eliminates the microcavity structure from the sub-pixel design. By removing this angle-sensitive optical element, the display achieves wide viewing angles without color shift while maintaining adequate luminance through alternative optical design approaches.
4Measurement precision
If WOLED display devices use color filters in addition to blue and yellow/orange OLEDs for each sub-pixel to emit red, green, and blue light, then color gamut is improved, but light efficiency is reduced due to color filtering
Solution Approach 1:
The patent extracts and removes the color filter layer from the display structure. By eliminating this light-absorbing component, the display achieves high light efficiency while maintaining wide color gamut through the use of QLED and OLED light sources that emit their respective colors directly without requiring filtering.
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 configuration enhances light efficiency, reduces manufacturing costs, and provides high contrast ratios, wider viewing angles, and improved color accuracy without the drawbacks of traditional OLEDs, such as burn-in and color shifting.
Implementation Method 1
a quantum dot (QD) film, and a blocking layer disposed on the QD film
Implementation Method 2
a first portion of an organic phosphor film disposed on the blocking layer
Data Source
AI summary
Embodiments of a display device are described. A display device includes first and second sub-pixels. The first sub-pixel includes a first light source having a quantum dot (QD) film, a blocking layer disposed on the QD film, and a first portion of an organic phosphor film disposed on the blocking layer and a first substrate configured to support the first light source. The blocking layer is configured to prevent emission of light from the first portion of the organic phosphor film and the QD film is configured to emit a primary emission peak wavelength in a red, green, cyan, yellow, or magenta wavelength region of an electromagnetic (EM) spectrum. The second sub-pixel includes a second light source and a second substrate configured to support the second light source. The second light source has a second portion of the organic phosphor film disposed adjacent to the QD film. The second portion of the organic phosphor film is configured to emit a primary emission peak wavelength in a blue, violet, or ultraviolet wavelength region of an EM spectrum.