OLED Hole Transporting Layer Thickness Optimization
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Solution Overview
Problem
Existing OLED devices face challenges in achieving uniform luminous efficiency and luminance across different pixel regions due to differences in optical film thicknesses, making it difficult to manufacture films of varying thicknesses for each color.
Innovation Solution
The OLED device incorporates a substrate with pixel regions of different colors, where the thickness of the hole transporting layers is optimized to be one-third to two-thirds of the optical wavelength difference between adjacent pixel regions, ensuring optimal optical resonance and uniformity in light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If different optical film thicknesses are used for each color pixel region, then luminance and luminous efficiency are improved, but manufacturing complexity increases due to requiring different manufacturing processes for each color
Solution Approach 1:
The patent applies local quality by forming hole transporting layers with different thicknesses in different pixel regions (red, green, blue) to match the specific optical requirements of each color. The red pixel region receives a first thickness, the green pixel region receives a second thickness, and the blue pixel region receives a third thickness, allowing each region to have optimized optical properties without requiring entirely different manufacturing processes.
Solution Approach 2:
The patent changes the thickness parameter of the hole transporting layer according to the wavelength characteristics of different colors. By adjusting the thickness parameter locally in each pixel region, the patent achieves optimal luminance and color purity for each color while using a unified layer formation process, thus resolving the contradiction between performance optimization and manufacturing complexity.
2Use of energy by moving object
If different optical film thicknesses are used for each color pixel region, then luminous efficiency is improved, but manufacturing difficulty increases as it becomes very difficult to form optical films of different thicknesses
Solution Approach 1:
The patent implements local quality by creating hole transporting layers with color-specific thicknesses within a unified manufacturing framework. Each pixel region (red, green, blue) receives the appropriate thickness during the same deposition process, achieving high luminous efficiency without requiring separate manufacturing lines or complex post-processing steps.
Solution Approach 2:
The patent achieves universality by using a single hole transporting layer material and deposition process that serves multiple functions: it provides hole transport for all colors while simultaneously achieving color-specific thickness optimization. This multi-functional approach allows different thicknesses to be formed in different regions through a unified process, greatly simplifying manufacturing.
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 results in improved luminous efficiency and luminance across all pixel regions, achieving optimal optical resonance and color purity by accounting for wavelength differences, thereby enhancing the overall display performance.
Implementation Method 1
the thickness of the hole transporting layers is optimized to be one-third to two-thirds of the optical wavelength difference between adjacent pixel regions, ensuring optimal optical resonance and uniformity in light emission
Implementation Method 2
An organic electroluminescent display device having a thin film transistor TFT is a self light-emissive type display device
Data Source
AI summary
The present invention discloses organic electroluminescent display device and a method for fabricating the same, which includes: a first hole transporting layer formed in the first, second, and third pixel regions; a second hole transporting layer formed on a portion of the first hole transporting layer in the second and third pixel regions; a third hole transporting layer formed on a portion of the second hole transporting layer in the third pixel region. Light emitting layers are formed on each of the first, second, and third hole transporting layers. The thickness of the second hole transporting layer is approximately one-third (⅓) to two-thirds (⅔) of an optical wavelength difference between the first and second pixel regions, and the thickness of the third hole transporting layer is approximately one-third (⅓) to two-thirds (⅔) of an optical wavelength difference between the second and third pixel regions.