OLED Display Microcavity Layer Thickness Optimization
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Solution Overview
Problem
OLED display devices face challenges in achieving uniform lifetime and efficiency for red, green, and blue light-emitting materials, leading to reduced lifetime and increased costs due to high reflection of external light and difficulties in applying thermal evaporation methods for large-size, high-definition displays.
Innovation Solution
The OLED display device incorporates red, green, and blue sub-pixel regions with specific light-emitting layers and color filters, utilizing yellow light-emitting materials with distinct emission peaks and varying thicknesses of hole auxiliary layers to optimize microcavity effects, thereby enhancing light emission and reducing external light reflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If thermal evaporation method is used to form light-emitting material layers, then manufacturing precision can be achieved, but it becomes difficult to apply to large-size, high-definition displays
Solution Approach 1:
The patent extracts the light-emitting material formation process from the thermal evaporation method and implements it through a solution process instead. This allows the manufacturing of large-size, high-definition displays while maintaining the ability to form precise light-emitting material layers through solution-based deposition techniques.
2Ease of manufacture
If red, green, and blue light-emitting materials are used with uniform thickness, then manufacturing is simplified, but uniform lifetime and efficiency cannot be achieved
Solution Approach 1:
The patent applies different thicknesses of hole auxiliary layers in different sub-pixel regions (red, green, blue) to achieve uniform lifetime and efficiency. Specifically, the hole auxiliary layer thickness is set to 250-280 nm for red sub-pixels, 310-330 nm for green sub-pixels, and 30-70 nm for blue sub-pixels, optimizing the microcavity effect for each color to resolve the contradiction between manufacturing simplicity and lifetime uniformity.
3Device complexity
If external light reflection is not addressed, then device complexity is reduced, but lifetime is reduced due to increased stress on light-emitting materials
Solution Approach 1:
The patent converts the harmful effect of external light reflection into a beneficial microcavity effect. By carefully designing the thickness of hole auxiliary layers and light-emitting material layers, the reflection of external light is utilized to enhance light emission efficiency and extend device lifetime, rather than simply blocking reflection with additional components.
4Duration of action of stationary object
If polarizers are added to reduce external light reflection, then lifetime is improved, but production costs increase
Solution Approach 1:
The patent eliminates the need for polarizers by converting external light reflection into a beneficial microcavity effect through precise layer thickness design. This approach improves device lifetime without increasing production costs, as it uses the existing reflective properties of the display structure rather than adding expensive polarizing components.
5Duration of action of stationary object
If yellow light-emitting materials with microcavity effects are used, then lifetime is increased, but device complexity increases due to specific layer thickness requirements
Solution Approach 1:
The patent optimizes the microcavity effect by precisely controlling the thickness parameters of hole auxiliary layers and light-emitting material layers. By setting specific thickness ranges (hole auxiliary layer: 250-330 nm for red/green, 30-70 nm for blue; light-emitting material layer: 50-100 nm), the device achieves extended lifetime while maintaining manageable complexity through standardized parameter specifications.
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 increases the lifetime of OLED display devices by using yellow light-emitting materials with microcavity effects and color filters to produce deep red and green lights, reducing the need for polarizers and lowering production costs.
Implementation Method 1
organic light-emitting diode (OLED) display devices, which can be referred to as organic electroluminescent display devices, emit light during loss of electron-hole pairs
Implementation Method 2
utilizing yellow light-emitting materials with distinct emission peaks and varying thicknesses of hole auxiliary layers to optimize microcavity effects, thereby enhancing light emission
Implementation Method 3
red, green, and blue color filters on the second electrode and corresponding to the red, green, and blue sub-pixel regions, respectively
Implementation Method 4
varying thicknesses of hole auxiliary layers to optimize microcavity effects, thereby enhancing light emission
Data Source
Figure 1~2
Figure 3~4
Figure 5A~5B
AI summary
An organic light-emitting diode display device includes a substrate (100) on which red (Pr), green (Pg) and blue (Pb) sub-pixel regions are defined; first electrodes (162) in the red (Pr), green (Pg) and blue (Pb) sub-pixel regions, respectively; first, second and third light-emitting layers (180) on the corresponding first electrodes (162) and in thered (Pr), green (Pg) and blue (Pb) sub-pixel regions, respectively; a second electrode (192) on the first, second and third light-emitting layers (180); and red (Rc), green (Gc) and blue (Bc) color filters (220) on the second electrode (192) and corresponding to the red (Pr), green (Pg) and blue (Pb) sub-pixel regions, respectively, wherein a thickness of the first light-emitting layer is smaller than a thickness of the second light emitting layer.