OLED Display Blue Sub-pixel Segmentation for Lifespan and Power
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Solution Overview
Problem
Conventional display devices with organic light emitting diodes (OLEDs) face reduced lifespan and increased power consumption when emitting deep blue light, as it approaches ultraviolet levels, leading to OLED molecule deterioration and lower luminance.
Innovation Solution
The display device divides blue sub-pixels into deep blue and cyan blue sub-pixels, with a signal controller generating changed image signals by adjusting the blue image signal based on driving modes, using a combination of fluorescent and phosphorescent materials to emit light at specific wavelengths, thereby maintaining white balance and gamma values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If deep blue light is emitted to approach ultraviolet levels, then the color quality is improved, but the OLED molecules deteriorate and lifespan decreases
Solution Approach 1:
The blue sub-pixels are segmented into two distinct types: deep blue sub-pixels (emitting at 440-480nm) and cyan blue sub-pixels (emitting at 480-520nm). This segmentation allows the display to achieve high-quality blue emission while distributing the operational stress across different OLED materials with varying lifespans, thereby extending overall device reliability
Solution Approach 2:
Different regions of the display (different sub-pixels) are assigned different emission characteristics. Deep blue sub-pixels use one type of OLED material while cyan blue sub-pixels use another type with different stability properties. This local quality differentiation enables optimal color performance in each region while maintaining overall system reliability
2Illumination intensity
If the luminance of deep blue is increased to maintain white balance, then the color accuracy is improved, but the OLED molecules deteriorate faster
Solution Approach 1:
The blue channel is segmented into deep blue and cyan blue sub-pixels that can be independently controlled. This allows the system to achieve required luminance levels by combining emissions from both sub-pixel types rather than over-driving deep blue sub-pixels alone, thereby reducing molecular deterioration
Solution Approach 2:
The system dynamically adjusts the emission parameters (luminance, color temperature) of deep blue and cyan blue sub-pixels based on operating conditions. By changing these parameters adaptively, the display maintains color accuracy and white balance while operating within reliability limits of the OLED materials
3Manufacturing precision
If blue sub-pixels are divided into deep blue and cyan blue sub-pixels, then the color precision is improved, but the device complexity increases
Solution Approach 1:
Each pixel is segmented into four sub-pixels (red, green, deep blue, cyan blue) instead of the conventional three. While this increases structural complexity, the segmentation enables precise color rendering by independently controlling two distinct blue emission wavelengths, achieving superior color precision and gamut coverage
Solution Approach 2:
The additional cyan blue sub-pixel serves multiple functions: it extends the color gamut, improves color accuracy, reduces the burden on deep blue sub-pixels (extending lifespan), and enables advanced features like bio-clock mode. This multi-functionality justifies the increased structural complexity
4Manufacturing precision
If the blue image signal is changed to maintain white balance with divided sub-pixels, then the color accuracy is improved, but the power consumption increases
Solution Approach 1:
The signal controller dynamically changes the emission parameters of deep blue and cyan blue sub-pixels based on the required luminance level and operating mode. At low luminance levels, it selectively activates only the necessary sub-pixel type, reducing power consumption while maintaining accurate white balance and color precision
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 extends the lifespan of the display device, reduces power consumption, and enables ultra-high definition color standards while providing bio-clock functions by selectively emitting cyan blue and deep blue light, improving the overall performance and longevity of OLEDs.
Implementation Method 1
an emission layer of the first blue sub-pixel may include a fluorescent material which emits blue light
Implementation Method 2
an emission layer of the second blue sub-pixel may include a phosphorescent material which emits blue light
Data Source
AI summary
A display device includes: a signal controller which receives an input image signal and generates a changed image signal, where the signal controller divides the inputted image signal into red, green and blue image signals, changes the blue image signal to a first blue image signal or a second blue image signal, matches white balance of the red, green, first blue or second blue image signals, and generates the changed image signal by compensating a gamma value of the red, green, first blue or second blue image signals; a display panel which displays an image corresponding to the changed image signal, where the display panel includes a pixel including red, green, first blue and second blue sub-pixels; and a data driver which receives the changed image signal from the signal controller and applies a data voltage corresponding to the changed image signal to the display panel.