Display Device Second Color Filter Reduces External Light Reflection
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Solution Overview
Problem
Display devices with metal pixel electrodes suffer from external light reflection, leading to display degradation, especially in outdoor use, as the reflected light is not adequately alleviated by existing solutions.
Innovation Solution
Incorporating a second color filter with a different color than the first color filter, positioned to overlap or be between the reflection electrode and the pixel electrode, to dampen unwanted light components and reduce reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a metal pixel electrode with high reflectance is used, then the light emission luminance is improved, but external light reflection increases causing display degradation
Solution Approach 1:
A color filter layer is introduced as an intermediary between the metal pixel electrode and the external light. This color filter selectively transmits the emission wavelength while absorbing or reflecting external light of different wavelengths, thereby reducing the harmful reflection effect while preserving the desired light emission
Solution Approach 2:
The patent applies color filtering to the pixel electrode structure by introducing a color filter layer that has specific optical transmission characteristics. The color filter is designed to transmit the emission wavelength of the light-emitting element while blocking external light, effectively changing the optical properties of the electrode system
2Device complexity
If a color filter of the same color is provided between the reflection electrode and pixel electrode, then the structure is simplified, but external light reflection is not adequately reduced
Solution Approach 1:
The patent changes the key parameter of the color filter from matching the pixel color to having complementary or contrasting color characteristics. Specifically, for green pixels, a magenta color filter is used; for red pixels, a cyan color filter is used. This parameter change optimizes the filtering effect by ensuring that the color filter absorbs the reflection wavelength while transmitting the emission wavelength
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
Effectively alleviates display degradation by minimizing external light reflection while maintaining the intended light emission, improving visibility in outdoor conditions.
Implementation Method 1
a first color filter located above the common electrode, the first color filter being green or red; and a second color filter located at a position overlapping the first color filter as seen in a plan view, the second color filter being yellow
Data Source
AI summary
A display device includes a reflection electrode located on a first substrate; a pixel electrode located above the reflection electrode; a common electrode located above the pixel electrode; a light emitting layer located between the pixel electrode and the common electrode; a first color filter located above the common electrode, the first color filter being green or red; and a second color filter located at a position overlapping the first color filter as seen in a plan view, the second color filter being yellow.