Hybrid Micro-LED OLED Display for High Yield and Efficiency
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Solution Overview
Problem
Current OLED display technologies face challenges in achieving high color accuracy, efficiency, and manufacturability due to issues with micro-LED yield, grey scale, and unsatisfactory lifetime, particularly in developing all micro-LED displays, which require near-perfect sub-pixel yield and are prone to color shift and temperature-dependent red micro-LED output.
Innovation Solution
A hybrid pixel arrangement combining inorganic micro-LEDs with organic emissive OLED stacks, where blue LEDs are used in conjunction with unpatterned yellow OLEDs and color filters to create a 'RGBY' display, allowing for shared blue LEDs among multiple pixels, reducing yield requirements and enabling high color saturation with lower power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If all micro-LED displays are used, then color saturation and efficiency are improved, but yield requirements become near-perfect and manufacturing complexity increases
Solution Approach 1:
The patent combines micro-LED technology with OLED technology in a hybrid display system. Specifically, it integrates blue micro-LEDs with yellow phosphorescent OLED layers to create a display that achieves high color saturation without requiring near-perfect yield from micro-LEDs alone. The micro-LEDs provide blue light while the phosphorescent OLED layer converts some blue light to yellow, effectively using both technologies' strengths.
Solution Approach 2:
The hybrid display system serves multiple functions: blue micro-LEDs provide direct blue emission for saturated blue subpixels, while also serving as a light source that excites the yellow phosphorescent OLED material. This multi-functionality allows the system to achieve high color saturation across multiple color channels without proportionally increasing manufacturing complexity.
2Use of energy by moving object
If micro-LED displays are developed, then efficiency is improved, but lifetime becomes unsatisfactory and color shift occurs
Solution Approach 1:
The patent merges micro-LED and OLED technologies to create a hybrid system where each technology compensates for the other's weaknesses. The micro-LEDs provide high efficiency blue light, while the phosphorescent OLED layer extends lifetime by using materials with proven long-term stability. The system achieves satisfactory lifetime without sacrificing efficiency because the phosphorescent OLED component has demonstrated reliability in previous applications.
Solution Approach 2:
The display uses composite material structures combining inorganic micro-LED materials with organic phosphorescent OLED materials. This composite approach allows the system to leverage the high efficiency of inorganic LEDs while incorporating the proven lifetime characteristics of organic phosphorescent materials, achieving both high efficiency and satisfactory lifetime simultaneously.
3Measurement precision
If red micro-LEDs are used, then color accuracy is improved, but output becomes temperature-dependent
Solution Approach 1:
The patent extracts the problematic temperature-dependent red micro-LED component from the system and replaces it with an alternative approach using green phosphorescent OLED material excited by blue micro-LEDs. This extraction eliminates the temperature dependence issue while maintaining color accuracy through the use of phosphorescent materials that have more stable emission characteristics across temperature ranges.
4Manufacturing precision
If hybrid pixel arrangement is used, then yield is improved, but device complexity increases
Solution Approach 1:
The patent merges two fabrication processes into a unified hybrid approach where blue micro-LEDs are integrated with yellow phosphorescent OLED layers in a single device structure. This merging improves yield by allowing the use of less stringent micro-LED specifications while maintaining high color saturation, and the integrated structure manages complexity through shared components and processes.
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 results in a full-color display with improved luminance, lifetime, yield, color accuracy, and optical performance, while simplifying fabrication and reducing power consumption, achieving a high color gamut without increased power requirements.
Implementation Method 1
a first sub-pixel configured to emit a first color, the first sub-pixel comprising an inorganic light-emitting diode (LED)
Implementation Method 2
OLEDs make use of thin organic films that emit light when voltage is applied across the device
Implementation Method 3
One application for phosphorescent emissive molecules is a full color display
Data Source
AI summary
A hybrid pixel arrangement for a full-color display is provided, which includes an inorganic LED in at least one sub-pixel, and an organic emissive stack in at least one other sub-pixel. In an embodiment, a first sub-pixel is configured to emit a first color, and includes an inorganic LED, a second sub-pixel is configured to emit a second color, and includes a first portion of a first organic emissive stack configured to emit an initial color different from the first color. A third sub-pixel is configured to emit a third color different from the initial color, and includes a second portion of the first organic emissive stack, and a first color altering layer disposed in a stack with the second portion of the first organic emissive stack.