Wavelength-Selective Absorption Filter for OLED Reflection Control
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Solution Overview
Problem
Existing OLED display devices face issues with external light reflection causing display defects and brightness decrease, and current light absorption filters either fail to suppress these issues effectively or alter the original tint of the display image.
Innovation Solution
A wavelength selective absorption filter comprising specific dyes A to D with defined absorbance ratios in different wavelength regions, including squarine-based coloring agents, is integrated into the OLED display device to suppress external light reflection and brightness decrease while maintaining the original tint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a circularly polarizing plate is provided to suppress external light reflection, then external light reflection is suppressed, but brightness decreases
Solution Approach 1:
The light absorbing layer is divided into multiple layers with different absorption characteristics. The first light absorbing layer absorbs light in the blue region (450-480nm), the second light absorbing layer absorbs light in the green region (500-540nm), and the third light absorbing layer absorbs light in the red region (600-680nm). This segmentation allows selective absorption of external light across different wavelength regions while maintaining brightness in the display wavelength range (480-680nm).
Solution Approach 2:
Each light absorbing layer is designed with specific absorption characteristics tailored to its function. The first layer targets blue external light, the second layer targets green external light, and the third layer targets red external light. This local quality approach ensures that each layer absorbs only the external light in its specific wavelength range while being transparent to the display light in other ranges, thereby suppressing external light reflection without decreasing overall brightness.
2Object-affected harmful factors
If a light absorbing layer with broad absorption is used to suppress external light reflection, then external light reflection is suppressed, but the original tint of the display image changes
Solution Approach 1:
The light absorbing layer is segmented into three distinct layers, each with specific absorption characteristics. The first light absorbing layer absorbs external light in the blue region (450-480nm) while being transparent to display light. The second light absorbing layer absorbs external light in the green region (500-540nm) while being transparent to display light. The third light absorbing layer absorbs external light in the red region (600-680nm) while being transparent to display light. This segmentation ensures that each layer selectively absorbs only external light in its specific wavelength range without affecting the original tint of the display image.
Solution Approach 2:
Each light absorbing layer is designed with localized absorption properties. The first layer has absorption characteristics specifically for blue external light, the second layer for green external light, and the third layer for red external light. This local quality approach ensures that the absorption characteristics are tailored to suppress external light in specific wavelength regions while maintaining the original tint of the display image in the visible range (480-680nm).
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 filter effectively reduces external light reflection and brightness loss while preserving the original image tint, ensuring high contrast and color fidelity in OLED displays.
Implementation Method 1
a wavelength selective absorption filter comprising: a resin; and the following dyes A to D each having a main absorption wavelength range in different wavelength regions
Implementation Method 2
an absorbance Ab(λ) of the wavelength selective absorption filter at a wavelength λ nm satisfies Relationships of Expressions (I) to (VI)
Data Source
AI summary
There are provided a wavelength selective absorption filter including a resin, and four types of dyes A to D each having a main absorption wavelength range in different specific wavelength regions, in which an absorbance Ab (λ) of the wavelength selective absorption filter at a wavelength λ nm satisfies specific Relational Expressions (I) to (VI), and an organic electroluminescent display device.