OLED Color Changing Layer Enhances Luminance and Gamut
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Solution Overview
Problem
OLED display devices face challenges in achieving improved color gamut and light efficiency due to the use of color filters that absorb different wavelengths of light, leading to decreased light efficiency and increased manufacturing time and costs, especially when incorporating a color changing layer that requires additional photolithography processes.
Innovation Solution
An OLED display device structure that includes a color changing layer absorbing blue light and emitting yellow light, overlapping with red and green color filters, which simplifies the manufacturing process by eliminating the need for additional photolithography steps while enhancing color gamut and light efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If color filters are used to produce red, green and blue lights in OLED display devices, then color gamut is improved, but light efficiency is decreased due to absorption of different wavelengths
Solution Approach 1:
The patent applies color changing materials that convert short wavelength light to long wavelength light, enabling the organic light-emitting layer to emit white light that is then converted to red, green, and blue light through wavelength transformation rather than absorption, thereby improving both color gamut and light efficiency
Solution Approach 2:
The patent changes the optical parameters by using color changing materials with specific absorption and emission characteristics, where the materials absorb blue light and emit yellow light, which then combines with red and green color filters to produce the desired color output with improved efficiency
2Stability of the object's composition
If a color changing layer is added to increase color gamut and light efficiency, then color performance is improved, but manufacturing time and costs increase due to additional photolithography processes
Solution Approach 1:
The patent merges the color changing layer formation with the existing color filter layer formation process, using the same photolithography steps to pattern both layers simultaneously, thereby avoiding additional manufacturing time and costs while achieving improved color gamut
3Stability of the object's composition
If different materials are used for red, green and blue organic light-emitting layers to achieve desired colors, then color output is improved, but light efficiencies and lifetimes of sub-pixels become different leading to performance imbalance
Solution Approach 1:
The patent uses the same organic light-emitting material for all sub-pixels, emitting white light uniformly, and achieves different color outputs through the color changing layer and color filter combination, ensuring homogeneous performance and lifetime across all sub-pixels while maintaining desired color output
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 increases red and green luminance by 3.6% and 4.3%, respectively, and color gamut by 0.4%, while reducing manufacturing time and costs by simplifying the fabrication process without additional photolithography steps, achieving improved color purity and light efficiency.
Implementation Method 1
a color changing layer overlapping the red and green color filters, the color changing layer absorbing blue light and emitting yellow light therefrom
Data Source
AI summary
An OLED display device includes a first substrate; organic light-emitting diodes each including a first electrode, an organic light-emitting layer and a second electrode on the first substrate; a passivation layer on the organic light-emitting diodes; a second substrate spaced apart from the first substrate; a color filter layer on an inner surface of the second substrate; and a color changing layer contacting the passivation layer and the color filter layer.