Organic EL Display Wavelength Conversion for Color Purity
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Solution Overview
Problem
Organic electroluminescent (EL) displays face challenges in achieving a wide color reproduction range and low power consumption due to trade-offs between color purity and luminance, particularly in blue and green pixels when using a wavelength conversion layer to convert blue-green electroluminescence into red light.
Innovation Solution
An organic electroluminescent display device with a blue pixel portion using a blue color filter, a green pixel portion using a green color filter, and a red pixel portion with a wavelength conversion layer that absorbs blue and green light components to emit red light, along with a low-refractive-index layer and light-distribution conversion layers to enhance color purity and luminance efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If white organic electroluminescence is combined with a color filter to achieve color display, then higher definition is achieved, but power consumption increases
Solution Approach 1:
The invention segments the color filter layer into multiple layers: a first color filter layer with first and second regions, and a second color filter layer with corresponding regions. This segmentation allows different portions of the display to use different filtering strategies, enabling high definition while managing power consumption through selective light transmission and conversion.
Solution Approach 2:
The invention introduces a wavelength conversion layer as an intermediary between the organic electroluminescence layer and the color filter layers. This wavelength conversion layer converts blue light to red light, allowing the system to achieve full-color display without requiring a white light source to be split by color filters, thereby reducing power consumption while maintaining high definition.
2Ease of manufacture
If blue-green organic electroluminescence is combined with a wavelength conversion layer to convert light into red light, then production is simplified, but color purity and luminance trade-off occurs
Solution Approach 1:
The invention divides the color filter structure into multiple segments: a first color filter layer with first and second regions, and a second color filter layer with corresponding first and second regions. The first region of each layer has different light transmission characteristics than the second region. This segmentation allows precise control over color purity and luminance in different pixel regions while maintaining simplified production through a unified wavelength conversion approach.
Solution Approach 2:
The invention applies different light transmission properties to different regions of the color filter layers. The first region allows certain wavelengths to pass while the second region blocks or filters different wavelengths. This local differentiation of optical properties enables optimization of color purity and luminance for specific pixel types (blue, green, red) while using a common wavelength conversion layer, thus resolving the trade-off between manufacturing simplicity and color quality.
3Manufacturing precision
If light is split into blue and green pixels with a color filter in an organic EL display, then color display is achieved, but luminance is reduced due to trade-off with color purity
Solution Approach 1:
The invention segments the color filter into multiple layers with first and second regions in each layer. The first region is configured to transmit light for blue pixel portions, while the second region transmits light for green pixel portions. This segmentation allows each pixel type to receive optimized light transmission without excessive filtering, maintaining high luminance while achieving required color purity through the combined effect of multiple filter regions.
Solution Approach 2:
The wavelength conversion layer acts as an intermediary that converts blue light to red light before it reaches the color filter layers. This intermediary conversion allows the color filter layers to focus on optimizing blue and green transmission without having to simultaneously manage red light filtering, thereby improving luminance efficiency for blue and green pixels while maintaining color purity through the coordinated action of segmented filter regions.
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
The solution enables full-color display with a wide color reproduction range and low power consumption, improving viewing angle characteristics and luminous efficiency by efficiently splitting and converting light emissions in the organic EL display device.
Implementation Method 1
a red pixel portion including a wavelength conversion layer configured to absorb at least one of the light component in the blue wavelength region and the light component in the green wavelength region of the light emitted from the organic electroluminescent section and emit light in a red wavelength region
Implementation Method 2
a blue pixel portion including a blue color filter configured to mainly transmit a light component in a blue wavelength region of light emitted from the organic electroluminescent section
Implementation Method 3
a green pixel portion including a green color filter configured to mainly transmit a light component in a green wavelength region of the light emitted from the organic electroluminescent section
Data Source
AI summary
An organic EL display device includes an organic EL section including an organic layer held between a first electrode and a second electrode, one of the two electrodes serving as a reflective electrode, and the other serving as a translucent electrode; a blue pixel portion including a blue color filter configured to mainly transmit a light component in a blue wavelength region of light emitted from the organic EL section; a green pixel portion including a green color filter configured to mainly transmit a light component in a green wavelength region of the light emitted from the organic EL section; and a red pixel portion including a wavelength conversion layer configured to absorb at least one of the light component in the blue wavelength region and the light component in the green wavelength region of the light emitted from the organic EL section and emit light in a red wavelength region.