Display Light-Emitting Layers with Dopant-Selective Pixel Isolation
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Solution Overview
Problem
In display apparatuses, light-emitting devices in adjacent pixel areas experience leakage currents due to direct contact between hole transport layers and charge generation layers, leading to unintended light emission in non-intended areas.
Innovation Solution
The display apparatus includes a structure where the hole transport layers and charge generation layers of different pixel areas are spaced apart, with varying p-type dopant contents in these layers to prevent leakage currents, ensuring each pixel area maintains its intended color emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the light-emitting units of adjacent pixel areas are partially connected to enable current flow, then the device can operate with connected structures, but leakage current occurs between pixel areas causing unintended light emission
Solution Approach 1:
The patent applies local quality by creating different dopant concentrations in the hole transport layer at different locations. The first hole transport layer has a first dopant concentration while the second hole transport layer has a second dopant concentration, allowing localized control of electrical properties to prevent leakage current while maintaining operational functionality.
Solution Approach 2:
The patent changes the dopant concentration parameter in the hole transport layer to resolve the contradiction. By adjusting the dopant concentration from the first concentration in the first hole transport layer to the second concentration in the second hole transport layer, the patent controls current flow characteristics to prevent leakage while maintaining necessary connectivity.
2Device complexity
If the hole transport layer and charge generation layer are in direct contact between adjacent pixel areas, then the structure is simplified and easier to manufacture, but driving current leaks from one pixel area to another
Solution Approach 1:
The patent implements local quality by creating spatially varying dopant concentrations within the hole transport layer. The first hole transport layer and second hole transport layer have different dopant concentrations that are specifically designed to prevent current leakage while maintaining the overall structural simplicity of the device.
3Ease of manufacture
If uniform dopant content is used in the hole transport layer across all pixel areas, then the manufacturing process is simplified, but leakage current occurs and color accuracy is compromised
Solution Approach 1:
The patent applies local quality by implementing different dopant concentrations in different regions of the hole transport layer. The first hole transport layer has a first dopant concentration and the second hole transport layer has a second dopant concentration, which is specifically designed to prevent leakage current and maintain color accuracy while remaining manufacturable.
Solution Approach 2:
The patent changes the dopant concentration parameter spatially across the device. By transitioning from a uniform dopant distribution to a non-uniform distribution with specific concentration values in different hole transport layers, the patent achieves both manufacturability and precise color control without excessive manufacturing complexity.
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 configuration minimizes leakage currents and improves the efficiency and color accuracy of each pixel area, preventing unintended light emission and enhancing the overall image quality.
Implementation Method 1
at least one hole transport layer that can handle a hole that can be used in generating the light of the specific color
Implementation Method 2
a charge generation layer and at least one hole transport layer that can handle a hole that can be used in generating the light of the specific color
Data Source
AI summary
Discussed is display apparatus in which a light-emitting device includes a charge generation layer and at least one hole transport layer is provided. The hole transport layer and/or the charge generation layer of each pixel area can be spaced apart from the hole transport layer and/or the charge generation layer of adjacent pixel area. The hole transport layer and/or the charge generation layer on the pixel area displaying a blue color can include a content of p-type dopant lower than the hole transport layer and/or the charge generation layer on the pixel region that displays a color other than blue. Thus, in the display apparatus, a leakage current between the pixel areas can be minimized. Therefore, in the display apparatus, efficiency of each pixel area can be improved.