Dual-Substrate OLED Display for High Aperture Ratio
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Solution Overview
Problem
Conventional flat panel display devices, particularly active matrix OLEDs, face challenges in reducing the size of TFTs and capacitors, leading to a decrease in aperture ratio and increased weight and size, making them unsuitable for small and lightweight electronic devices.
Innovation Solution
The solution involves attaching two substrates with OLEDs formed on each, allowing for increased aperture ratio and reduced thickness by independently driving the OLED display elements, which can be configured as active or passive matrix, and emitting light in the same direction, thereby enhancing the device's lifespan and preventing image sticking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If TFTs and capacitors are integrated in conventional active matrix OLEDs, then the display can be driven actively, but the size of TFTs and capacitors cannot be reduced further, leading to decreased aperture ratio
Solution Approach 1:
The patent divides the OLED structure into two separate substrates: a first substrate containing the TFT and capacitor, and a second substrate containing the OLED light-emitting structure. This segmentation allows independent optimization of each substrate, enabling the TFT and capacitor to be positioned in the non-emission region while the emission region on the second substrate achieves higher aperture ratio without being constrained by the size of the driving circuit components.
2Ease of operation
If the emission region is decreased to accommodate TFTs and capacitors, then the display can be driven, but the aperture ratio is reduced
Solution Approach 1:
The patent transitions from a single-substrate planar arrangement to a multi-substrate three-dimensional configuration. By stacking the first substrate (with TFT and capacitor) and the second substrate (with OLED emission structure) in the thickness direction, the emission region on the second substrate can be maximized in the planar area without being constrained by the driving circuit components, which are positioned on the first substrate. This dimensional change effectively separates the functional requirements and resolves the conflict between driving capability and emission area.
3Device complexity
If conventional single substrate OLED structure is used, then the structure is simple, but the thickness and weight are increased, making it unsuitable for small-sized devices
Solution Approach 1:
The patent segments the OLED display into two separate substrates that can be independently manufactured and then bonded together. This segmentation allows for thin-film construction of each substrate, reducing the overall thickness and weight compared to a conventional single-substrate structure that would require thicker active layers to accommodate all components. The segmented approach enables the use of lightweight transparent substrates and thin-film materials while maintaining structural integrity.
4Area of stationary object
If TFTs and capacitors are made smaller to increase aperture ratio, then the emission region can be increased, but the reliability of driving circuit may be compromised
Solution Approach 1:
The patent segments the functional components into two separate substrates: the first substrate houses the TFT and capacitor with sufficient area for reliable operation, while the second substrate provides the OLED emission structure with maximized aperture ratio. This segmentation allows each substrate to be optimized independently - the driving circuit components can be sized appropriately for reliability on the first substrate, while the emission region on the second substrate achieves high aperture ratio without compromise.
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 results in an ultra-slim flat panel display with an improved aperture ratio of over 70% and extended lifespan by optimizing the arrangement of OLEDs on two substrates, allowing for different functionalities and reducing the risk of image sticking.
Implementation Method 1
a first OLED display element having a first pixel electrode disposed on a first substrate, a first opposite electrode, a first organic layer including at least an emission layer; and a second OLED display element correspondingly attached to a second substrate
Implementation Method 2
an organic layer (not shown) including at least an emission layer and an opposite electrode are formed on the entire surface of the resultant structure
Data Source
AI summary
A flat panel display device capable of implementing an ultra-slim flat panel display device having an improved aperture ratio by attaching two substrates having independently drivable OLED display elements respectively formed thereon to emit light in the same direction, without a separate sealing process, and preventing image sticking due to a reduction of lifetime of the emission layer, by using the OLED display elements in different uses.