OLED Pixel Unit Light-Filtering Layer for Contrast
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Solution Overview
Problem
Conventional OLED display panels face challenges in maintaining high contrast and brightness levels due to external light reflection from metallic bottom electrode layers, which affects image color and contrast performance, especially in bright environments.
Innovation Solution
The display panel pixel unit incorporates a light-filtering layer above the electrode layer, creating a light-filtering area and a non-light-filtering area to selectively block or filter reflected external light, while allowing emitted light to pass through the non-light-filtering area, thereby reducing external light reflection and enhancing contrast and brightness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a metallic bottom electrode layer is used to drive the light-emitting layer, then the light-emitting element can be effectively driven to emit light, but external light entering the pixel unit will be reflected by the electrode layer, affecting contrast and color performance
Solution Approach 1:
The patent segments the bottom electrode layer into multiple sub-electrode layers with different materials and functions. The first bottom electrode layer (metallic) provides driving capability, while the second bottom electrode layer (transparent conductive oxide) reduces reflection. This segmentation allows each layer to perform its specific function independently, resolving the contradiction between light emission capability and external light reflection.
Solution Approach 2:
The patent uses composite material structure for the bottom electrode, combining metallic material (first bottom electrode layer) with transparent conductive oxide material (second bottom electrode layer). This composite structure maintains the electrical conductivity needed for light emission while the transparent conductive oxide layer reduces external light reflection, thus resolving the technical contradiction.
2Object-affected harmful factors
If the bottom electrode layer is made transparent to reduce reflection, then external light reflection is decreased, but the driving capability and light emission efficiency are reduced
Solution Approach 1:
The bottom electrode is divided into two functional segments: the first bottom electrode layer (metallic) that provides strong electrical conductivity for effective light emission driving, and the second bottom electrode layer (transparent conductive oxide) that reduces external light reflection. This segmentation allows the system to achieve both transparency for reflection reduction and sufficient conductivity for light emission capability.
Solution Approach 2:
The patent employs composite materials where the first bottom electrode layer uses metallic material for high conductivity, and the second bottom electrode layer uses transparent conductive oxide material for reflection reduction. This composite material approach ensures that transparency and light emission capability are both optimized simultaneously.
3Object-affected harmful factors
If a light-filtering layer is added to block reflected light, then contrast and color performance are improved, but the device structure and manufacturing complexity increase
Solution Approach 1:
The patent merges the light-filtering function with the bottom electrode structure by integrating the second bottom electrode layer (transparent conductive oxide) that simultaneously serves as both an electrode and a reflection-reducing layer. This merging eliminates the need for separate light-filtering layers, thus improving contrast performance while avoiding increased structural complexity.
Solution Approach 2:
The second bottom electrode layer performs multiple functions: it serves as an electrical electrode for driving the light-emitting element and simultaneously acts as a reflection-reducing layer due to its transparent conductive oxide material properties. This multi-functionality reduces the need for additional components, maintaining structural simplicity while improving contrast and color performance.
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 effectively decreases external light reflection, increasing contrast and brightness levels, thereby improving the overall display performance and color accuracy of OLED panels, especially in outdoor or brightly lit environments.
Implementation Method 1
The light-filtering layer has a light-filtering area and a non light-filtering area. The light-filtering area corresponds to the portion of the first electrode layer without and not exposed by the light-emitting element. As a result, a majority of the reflected light arrives at the light-filtering layer through the first electrode layer, and then are selectively blocked or filtered by the light-filtering layer.
Data Source
AI summary
A display panel pixel unit and display panel using the same is provided. The display panel pixel unit includes a first electrode layer, a light-emitting element, and a light-filtering layer. The light-emitting element is disposed on the first electrode layer. The light-emitting element has a light-emitting surface on the side opposite to the first electrode layer. The light-filtering layer is above the first electrode layer and forms a space with the first electrode layer to contain at least a portion of the light-emitting element. The light-filtering layer has a light-filtering area corresponding to the area of the first electrode layer that is exposed by the light-emitting element and light-transmissible area corresponding to the light-emitting surface.