OLED Pixel Layout Using Blue Emission and Quantum Dot Conversion
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Solution Overview
Problem
Current OLED displays face challenges in achieving high efficiency and long lifetime for deep blue sub-pixels, especially when using phosphorescent materials, and require pixel patterning which complicates large area substrate fabrication and reduces performance.
Innovation Solution
The use of light blue phosphorescent OLEDs with deep blue sub-pixels formed by filtering or microcavity design, and red and green sub-pixels generated through quantum dot down-conversion, allowing for unpatterned deposition and shared deep blue sub-pixels to reduce lifetime requirements and improve fill factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If pixel patterning is used to create deep blue sub-pixels, then color saturation is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent extracts the color filtering function from the pixel patterning process by using color conversion layers that convert a broad spectrum light source into specific colors. This removes the need for complex pixel-level patterning of different emissive materials, simplifying the device structure while maintaining color saturation.
Solution Approach 2:
The patent introduces color conversion layers as intermediary elements between the light source and the viewer. These layers act as mediators that transform the broad spectrum light into specific colors (including deep blue) without requiring the OLED structure itself to be patterned at the pixel level.
2Use of energy by moving object
If phosphorescent materials are used for deep blue sub-pixels, then efficiency is improved, but lifetime is reduced
Solution Approach 1:
The patent changes the emission parameters by using a light blue phosphorescent OLED with peak emission around 470-480nm instead of traditional deep blue materials. This parameter change allows the use of phosphorescent materials (which have high efficiency) while avoiding the severe lifetime issues associated with deep blue phosphorescent materials, as the slightly longer wavelength has better material stability.
3Ease of manufacture
If unpatterned deposition is used for large area substrates, then manufacturing ease is improved, but color purity is reduced
Solution Approach 1:
The patent uses color conversion layers as intermediaries that are deposited in a patterned manner after the unpatterned light blue phosphorescent OLED layer is formed. This allows the bulk OLED material to be deposited simply and uniformly over large areas, while the subsequent color conversion layer patterning provides the necessary color purity without complicating the main OLED fabrication process.
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 approach enables a highly efficient, unpatterned OLED display with improved color gamut and reduced manufacturing complexity, achieving a Rec2020 color space with extended deep blue sub-pixel lifetime and increased fill factor.
Implementation Method 1
light blue phosphorescent organic light emitting diode (OLED)
Implementation Method 2
red and green sub-pixels that may be enabled by filtering, cavity design, or downconversion
Data Source
AI summary
Embodiments of the disclosed subject matter provide a full-color pixel arrangement for a device, the full-color pixel arrangement including a plurality of sub-pixels, each having an emissive region of a first color, where the full-color pixel arrangement comprises emissive regions having exactly one emissive color that is a red-shifted color of a deep blue sub-pixel of the plurality of sub-pixels. Embodiments of the disclosed subject matter may also provide a full-color pixel arrangement for a device, the full-color pixel arrangement including a plurality of sub-pixels, each having an emissive region of a first color, where the full-color pixel arrangement comprises emissive regions having exactly one emissive color, and where the plurality of sub-pixels comprise a light blue sub-pixel, a deep blue sub-pixel, a red sub-pixel, and a green sub-pixel.