Dual Panel OLED Aperture Ratio and Moisture Protection
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Solution Overview
Problem
Existing OELD devices face challenges in achieving high aperture ratios and productivity, with bottom emission mode devices having reduced aperture ratios and top emission mode devices facing limitations in light transmittance and material choices for cathodes, leading to reduced light-emitting efficacy and increased manufacturing costs.
Innovation Solution
A dual panel-type OELD device is developed with a first substrate having an array element layer and connection patterns, and a second substrate with a color filter layer and overcoat layer made of hygroscopic materials, allowing for top emission mode operation and improved moisture protection, which enhances aperture ratio and productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If bottom emission mode is used, then light can be transmitted through transparent electrode, but aperture ratio is reduced
Solution Approach 1:
The device is divided into two separate panels: a first panel containing the organic electroluminescent diode structure, and a second panel containing the color filter and transparent electrode. This segmentation allows the light emission function and light transmission function to be separated spatially, enabling top emission mode operation with high aperture ratio while maintaining light transmittance through the transparent electrode in the second panel.
2Area of moving object
If top emission mode is used, then aperture ratio is improved, but light transmittance and material choices are limited
Solution Approach 1:
By separating the OLED structure from the color filter and transparent electrode into different panels, the invention enables top emission mode operation with high aperture ratio. The second panel can incorporate various transparent conductive materials and color filter configurations, providing material versatility while maintaining high light transmittance and aperture ratio.
Solution Approach 2:
The second panel serves multiple functions: it acts as a color filter layer, a transparent electrode, and a protective encapsulation layer. This multi-functionality allows for flexible material selection and design variations while maintaining the top emission mode operation and high aperture ratio performance.
3Ease of manufacture
If conventional single panel structure is used, then manufacturing is simpler, but productivity and yield are reduced
Solution Approach 1:
The display device is divided into two separately fabricable panels that can be manufactured independently using conventional OLED fabrication processes. This segmentation allows for optimized manufacturing of each panel separately, improving yield by isolating defects to individual panels, while the final assembly process remains relatively simple. The separate panels can be tested and quality-checked independently before final assembly.
4Device complexity
If no moisture protection is provided, then device structure is simpler, but operational reliability is reduced
Solution Approach 1:
The second panel serves as an encapsulation structure that provides moisture protection for the organic electroluminescent diode in the first panel. By separating the moisture barrier function into the second panel, the overall device structure remains relatively simple while achieving effective protection against moisture infiltration, thereby extending operational lifespan and improving reliability.
Solution Approach 2:
The second panel with transparent electrode and color filter is designed to provide beforehand protection against moisture and environmental damage. This encapsulation structure is prepared in advance to cushion and protect the sensitive organic electroluminescent diode from moisture infiltration and operational degradation, ensuring long-term reliability without significantly increasing structural 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
The dual panel-type OELD device achieves high aperture ratios, improved yield, and operational reliability by preventing moisture infiltration and reducing dark spots, resulting in high-definition images and extended operational lifespan.
Implementation Method 1
an organic light-emitting layer 54 and a second electrode 56 sequentially formed on the array element layer AL. Accordingly, light emitted from the organic light-emitting layer 54
Implementation Method 2
an overcoat layer disposed on the color filter layer, the overcoat layer including a hygroscopic material
Data Source
AI summary
A dual panel-type organic electroluminescent display device includes first and second substrates facing and spaced apart from each other, an array element layer disposed along an inner surface of the first substrate, the array element including a thin film transistor, a connection pattern disposed on the array element layer and electrically connected to the thin film transistor, a color filter layer disposed along an inner surface of the second substrate, the color filter layer including red, green, and blue color filters, an overcoat layer disposed on the color filter layer, the overcoat layer including a hygroscopic material, an organic electroluminescent diode disposed on the overcoat layer and connected to the connection pattern, the organic electroluminescent diode including a first electrode, an organic light-emitting layer, and a second electrode sequentially formed on the overcoat layer, and the organic light-emitting layer emits substantially monochromatic light, and a seal pattern along peripheral portions between the first and second substrates.