Mixed-Source Pixel Structure for Blue Sub-Pixel Lifetime
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Solution Overview
Problem
Current LED display devices face limitations such as wasted light, reduced luminance, and color shifting due to the use of LCDs, WOLEDs, RGB OLEDs, and QLEDs, particularly with blue sub-pixels having shorter operational lifetimes and lower efficiency compared to red and green sub-pixels, leading to issues like burn-in and dramatic color shifts at off-normal viewing angles.
Innovation Solution
Incorporating OLED and/or QLED as light sources in red and green sub-pixels and blue microLED or miniLED in blue sub-pixels, allowing for independent control and improving efficiency and lifetime by using microLEDs or miniLEDs with higher energy efficiency and longer operational lifetimes compared to traditional blue OLEDs or QLEDs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If blue OLEDs or QLEDs are used in blue sub-pixels, then the display device can achieve color emission, but the operational lifetime and efficiency are shorter and lower compared to red and green sub-pixels
Solution Approach 1:
The display device segments the light source technology by sub-pixel type: blue sub-pixels use microLEDs or miniLEDs while red and green sub-pixels use OLEDs or QLEDs. This segmentation allows each sub-pixel type to use the most appropriate technology for its specific requirements, particularly addressing the shorter lifetime and lower efficiency of blue OLEDs/QLEDs by replacing them with more efficient microLEDs/miniLEDs.
Solution Approach 2:
The patent applies different light source technologies to different locations (sub-pixels) based on their specific performance requirements. Blue sub-pixels, which have critical lifetime and efficiency requirements, receive the specialized treatment of using microLEDs or miniLEDs instead of standard OLEDs or QLEDs, while red and green sub-pixels can use other technologies.
2Illumination intensity
If LCDs with color filter arrays are used, then the display device can produce red, green, and blue sub-pixels, but there is wasted light and reduced luminance due to color filtering
Solution Approach 1:
The invention extracts and eliminates the color filter array component from the display structure by using self-emissive microLEDs/miniLEDs that inherently emit their specific color wavelengths. This removes the need for color filtering, thereby eliminating the light waste and luminance reduction that occurs when light passes through color filters in LCDs.
Solution Approach 2:
The patent replaces the passive optical filtering mechanism (color filter arrays in LCDs) with an active light emission mechanism (microLEDs/miniLEDs that directly emit their color). This substitution eliminates the need for light to pass through filters, thereby preventing light waste and maintaining higher luminance.
3Measurement precision
If microcavities are used in RGB OLED-based display devices to enhance forward emission, then color purity increases, but luminance drops precipitously and color shifts dramatically at off-normal viewing angles
Solution Approach 1:
The display device segments the sub-pixel technologies, using microLEDs or miniLEDs for blue sub-pixels instead of RGB OLEDs. This segmentation avoids the need for microcavity structures in blue sub-pixels, thereby maintaining both color purity and wide viewing angles without the dramatic color shifts and luminance drops that occur with microcavities at off-normal viewing angles.
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 the energy efficiency and operational lifetime of LED display devices, reducing waste and maintaining color accuracy across various viewing angles, thereby overcoming the limitations of existing technologies.
Implementation Method 1
The multi-layer stack includes an organic phosphor film or a quantum dot (QD) based phosphor film configured to emit a first light having a first peak wavelength
Implementation Method 2
The second light source has a microLED or a miniLED configured to emit a second light having a second peak wavelength that is different from the first peak wavelength
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 multi-layer stack and a first substrate configured to support the first light source. The multi-layer stack includes an organic phosphor film or a quantum dot (QD) based phosphor film configured to emit a first light having a first peak wavelength. The first substrate includes a first control circuitry configured to independently control the first light source. 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 microLED or a miniLED configured to emit a second light having a second peak wavelength that is different from the first peak wavelength. The second peak wavelength can be in the blue wavelength region of the visible spectrum. The second substrate includes a second control circuitry configured to independently control the second light source.