OLED Multicolor Display Shared Emission Layers
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Solution Overview
Problem
Multicolor OLED displays face challenges in power efficiency due to the need for precise patterning of OLED layers, which increases manufacturing complexity and power consumption, especially since the human eye is less sensitive to red and blue light, requiring these pixels to emit more light to achieve desired brightness.
Innovation Solution
A multicolor OLED display design featuring at least three differently colored pixels with a common light emitting layer for two pixels and a separate layer for the third, along with color filters to achieve the desired spectral components, reducing the need for precise patterning and alignment of OLED layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If separate OLED electroluminescent layers are provided for each pixel to achieve precise color control, then color accuracy is improved, but manufacturing complexity and alignment precision requirements increase
Solution Approach 1:
The patent combines multiple electroluminescent layers (first light emitting layer for red and green pixels, second light emitting layer for green and blue pixels) that are commonly shared across multiple pixel types. This merging approach reduces the total number of separate layers that need to be patterned and aligned, thereby reducing manufacturing complexity while maintaining color accuracy through the use of color filters.
Solution Approach 2:
The electroluminescent layers are designed to serve multiple functions: the first light emitting layer serves both red and green pixels, while the second light emitting layer serves both green and blue pixels. This multi-functionality reduces the number of patterning steps required compared to providing separate layers for each pixel type.
2Illumination intensity
If red and blue pixels emit more light to compensate for lower human eye sensitivity, then desired brightness is achieved, but power consumption increases
Solution Approach 1:
The patent introduces yellow and cyan pixels that emit light at wavelengths to which the human eye is more sensitive. By using color filters to convert the emission from these pixels (yellow pixels with red/cyan filters, cyan pixels with green/magenta filters), the display achieves the desired color output with lower power consumption compared to emitting more intense red and blue light directly.
Solution Approach 2:
The patent changes the spectral parameters of light emission by using yellow and cyan emitting layers instead of relying solely on red and blue emitting layers. This parameter change in emission wavelength allows the human eye to perceive the required brightness more efficiently, reducing the total power consumption of the display.
3Manufacturing precision
If shadow masks are used to pattern OLED layers for precise pixel alignment, then patterning accuracy is improved, but manufacturing throughput decreases due to alignment complexity
Solution Approach 1:
The patent merges the patterning requirements for multiple electroluminescent layers by designing them to be commonly shared across multiple pixel types. This reduces the number of separate shadow mask alignment operations required, thereby improving manufacturing throughput while maintaining adequate patterning accuracy through the reduced number of alignment steps.
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 design simplifies manufacturing, reduces power consumption, and enhances power efficiency by allowing for fewer precise alignments and patterning steps, while maintaining effective color production.
Implementation Method 1
an OLED is comprised of an anode for hole injection, a cathode for electron injection, and an organic media sandwiched between these electrodes to support charge recombination that yields emission of light
Implementation Method 2
first and second color filters in operative relationship with the first and second pixels
Data Source
AI summary
An OLED display having at least first, second, and third differently colored pixels includes a first light emitting layer provided over a substrate for the first and second pixels and a second light emitting layer provided over the substrate for the first, second, and third pixels, wherein the first and second light emitting layers produce light having different spectra, and wherein the light produced by overlapping the first and second light emitting layers has substantial spectral components corresponding to the light output desired for the first and second pixels, and the light produced by the second light emitting layer has substantial spectral components corresponding to the light output desired for the third pixel; and first and second color filters in operative relationship with the first and second pixels.