Organic Light-Emitting Device Optical Compensation Layer
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Solution Overview
Problem
Top light emitting type organic light emitting devices face challenges in controlling optical length for optimal microcavity effect, leading to reduced aperture ratio and light emitting efficiency, especially in displays requiring multiple TFTs, due to limitations in existing methods for controlling the thickness of electrodes and organic material layers.
Innovation Solution
Forming a layer with a refractive index between 1.3 and 3 on the upper electrode of the organic light emitting device, allowing for easier control of optical length and improved light emitting efficiency by adjusting the thickness of the upper electrode and refractive index layer based on the color of emitted light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the thickness of the lower electrode is controlled to adjust optical length for different colors, then the microcavity effect can be optimized for specific wavelengths, but the mask lifespan is reduced and manufacturing complexity increases
Solution Approach 1:
The patent introduces an optical compensation layer as an intermediary element between the lower electrode and the organic light-emitting layer. This separate layer specifically designed for optical path adjustment allows precise control of the microcavity effect without requiring complex mask management for electrode thickness control, thereby resolving the contradiction between manufacturing precision and device complexity
Solution Approach 2:
The patent segments the electrode structure by separating the lower electrode into two functional parts: the conductive lower electrode layer and the optical compensation layer. This segmentation allows independent optimization of electrical conductivity and optical properties, enabling precise optical length control through the compensation layer thickness without affecting the electrode's electrical function, thus reducing mask management complexity while maintaining manufacturing precision
2Manufacturing precision
If the thickness of the organic material layer is controlled to adjust optical length, then the light emitting spectrum can be optimized, but the driving voltage increases and manufacturing difficulty increases
Solution Approach 1:
The optical compensation layer serves as a dedicated intermediary for optical path length adjustment, decoupling the optical optimization function from the organic material layer thickness control. This allows the organic material layer thickness to be optimized for electrical performance and manufacturing ease, while the compensation layer thickness independently controls the optical spectrum, thereby reducing driving voltage while maintaining spectral optimization
Solution Approach 2:
The patent applies local quality by giving different functional characteristics to different layers: the lower electrode provides electrical conductivity, while the optical compensation layer provides optical path adjustment. This localized functional assignment allows the organic material layer to maintain optimal thickness for low driving voltage, while the compensation layer locally adjusts optical properties to achieve spectrum optimization without increasing power consumption
3Illumination intensity
If a reflective layer is added at the lower part of the anode to maximize light output, then light emission intensity is improved, but the device structure becomes more complex and manufacturing becomes more difficult
Solution Approach 1:
The patent merges the optical compensation function with the lower electrode structure by integrating the compensation layer directly onto the lower electrode. This merging eliminates the need for separate reflective layers and additional structural elements, achieving light output enhancement through optical interference control within the existing layer structure, thereby improving illumination intensity without increasing device complexity
Solution Approach 2:
The lower electrode structure is designed to serve multiple functions: electrical conductivity, optical reflection, and optical path compensation. By making the lower electrode structure multi-functional, the patent eliminates the need for separate dedicated reflective layers, reducing structural complexity while maintaining enhanced light output through the universal lower electrode assembly
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 approach enables precise control of optical length, enhancing light emitting efficiency and maintaining the required conductivity and transmittance for top-light emission, thereby improving the overall performance of the organic light emitting device.
Implementation Method 1
the upper electrode and the reflective layer that is provided at the lower part of the lower electrode act as mirrors, thus light that is emitted from the light emitting layer of the organic light emitting device is reflected by the mirrors. Accordingly, the destructive interference and the constructive interference of light occur, causing a phenomenon where only light having a predetermined wavelength is maintained and the intensity of light having the remaining wavelength is reduced. The phenomenon is called the microcavity effect.
Implementation Method 2
the destructive interference and the constructive interference of light occur, causing a phenomenon where only light having a predetermined wavelength is maintained
Implementation Method 3
A layer having a refractive index in the range of 1.3 to 3 is further formed on the upper electrode
Data Source
AI summary
The present invention provides an organic light emitting device in which a layer having a refractive index in the range of 1.3 to 3 is further formed on an upper electrode of at least one region of regions through which rays having red, green, and blue colors are passed and a method of manufacturing the organic light emitting device. An optical length that can cause the microcavity effect according to the type of color of emitted light is controlled by using the layer to manufacture the organic light emitting device having high light emitting efficiency.