OLED Pixel Layout Using Light and Deep Blue Sub-Pixels
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Solution Overview
Problem
Current OLED displays face challenges in achieving high efficiency and long lifetime for deep blue sub-pixels, particularly when using phosphorescent materials, and require pixel patterning which complicates large-area substrate fabrication and reduces performance.
Innovation Solution
The implementation of a full-color OLED display architecture utilizing light blue and deep blue sub-pixels, where deep blue sub-pixels are formed by filtering or microcavity design from the light blue emissive layer, and red and green sub-pixels are generated through quantum dot downconversion, allowing for unpatterned deposition over large areas and reducing the lifetime requirement for deep blue sub-pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If phosphorescent materials are used for deep blue sub-pixels, then color saturation is improved, but device lifetime deteriorates
Solution Approach 1:
The display is divided into multiple sub-pixel types including deep blue, light blue, cyan, green, yellow, orange, and red sub-pixels. By segmenting the blue channel into deep blue and light blue sub-pixels, the patent reduces the burden on phosphorescent deep blue sub-pixels, allowing them to operate at lower stress levels and extend their lifetime while maintaining color saturation through the combined output of multiple sub-pixel types.
Solution Approach 2:
The patent changes the spectral parameters by introducing light blue sub-pixels with peak wavelengths of 470-490nm alongside deep blue sub-pixels with peak wavelengths of 440-460nm. This parameter change allows the display to achieve high color saturation through the combination of multiple wavelengths while reducing the operational stress on phosphorescent deep blue materials, thereby extending their functional lifetime.
2Illumination intensity
If pixel patterning is applied, then color accuracy is improved, but manufacturing complexity increases
Solution Approach 1:
Instead of patterning a single emissive layer into different colors, the patent segments the display into multiple unpatterned sub-pixel types that naturally emit different colors. Each sub-pixel type (deep blue, light blue, cyan, green, yellow, orange, red) is deposited as a separate unpatterned layer, eliminating the need for complex pixel-level patterning while maintaining color accuracy through the combination of these segmented color channels.
Solution Approach 2:
The patent inverts the conventional approach by not patterning the emissive materials themselves, but rather by patterning the overlying electrode structures (anode or cathode) that control which sub-pixel types are activated in each pixel location. This inversion simplifies the emissive layer deposition process while maintaining the ability to achieve accurate colors through selective activation of unpatterned sub-pixel regions.
3Ease of manufacture
If unpatterned deposition is used, then manufacturing ease is improved, but deep blue sub-pixel performance deteriorates
Solution Approach 1:
The patent segments the blue emission into multiple unpatterned sub-pixel types (deep blue and light blue) that can be deposited using simple unpatterned deposition processes. By sharing the blue channel functionality across multiple sub-pixel types with different peak wavelengths, the patent maintains deep blue performance reliability while enjoying the manufacturing simplicity of unpatterned deposition, as no single sub-pixel type bears the full performance burden.
Solution Approach 2:
The patent changes the operational parameters of deep blue sub-pixels by introducing light blue sub-pixels to share the blue channel load. This parameter change allows deep blue sub-pixels to operate at reduced current densities and lower stress levels while maintaining overall deep blue performance, enabling the use of unpatterned deposition without sacrificing deep blue sub-pixel reliability.
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 highly efficient, unpatterned light blue phosphorescent OLEDs with improved deep blue sub-pixel performance, increasing color gamut and reducing manufacturing complexity by sharing deep blue sub-pixels across multiple pixels, thus enhancing display efficiency and longevity.
Implementation Method 1
a light blue sub-pixel and a deep blue sub-pixel, each having a phosphorescent light blue emissive layer
Implementation Method 2
red and green sub-pixels are generated through quantum dot 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.