Stacked OLED Structure for Dual Emission and Reduced Thickness
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Solution Overview
Problem
Existing dual emission type OLEDs face challenges in high fabrication costs, increased thickness, and reduced luminance due to separate panel fabrication or divided pixel structures.
Innovation Solution
A stacked structure of bottom-emission and top-emission type OLEDs with shared driving units and insulation layers, allowing for separate electrical connection and driving of each diode, while maintaining a high aperture ratio and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two separate panels are fabricated and attached to create a dual emission type OLED, then both top emission and bottom emission functions are achieved, but the fabrication cost increases and the device thickness increases
Solution Approach 1:
The patent combines two separate OLED panels into a single integrated structure where a first OLED and a second OLED are stacked and electrically connected through a shared first electrode. This merging eliminates the need for separate fabrication and attachment processes, reducing both fabrication cost and device thickness while maintaining dual emission functionality.
Solution Approach 2:
The first electrode serves multiple functions: it acts as the cathode for the first OLED and simultaneously as the anode for the second OLED. This multi-functionality reduces the total number of electrodes and simplifies the overall structure, contributing to lower fabrication costs and reduced device complexity.
2Adaptability or versatility
If two separate panels are fabricated and attached to create a dual emission type OLED, then both top emission and bottom emission functions are achieved, but the device thickness increases
Solution Approach 1:
The patent implements a nested structure where the first OLED and second OLED are stacked one on top of the other, with the first electrode serving as a common interface between them. This nesting approach allows both emission functions to be integrated within a compact vertical arrangement, significantly reducing the overall device thickness compared to attaching separate panels.
3Adaptability or versatility
If each pixel is divided into top emission region and bottom emission region, then dual emission function is achieved, but the light emitting area is reduced and luminance is reduced
Solution Approach 1:
Instead of dividing each pixel horizontally into top and bottom emission regions (2D division), the patent transitions to a vertical stacking arrangement where the first OLED and second OLED are positioned in the third dimension (depth). This dimensional change allows each pixel to maintain its full light emitting area while achieving dual emission through the stacked configuration, thereby preserving luminance.
4Ease of manufacture
If a stacked structure with shared driving units is used, then fabrication cost is reduced and device thickness is reduced, but device complexity increases
Solution Approach 1:
The shared first electrode performs dual functions as the cathode for the first OLED and the anode for the second OLED. This multi-functionality reduces the total number of electrodes and simplifies the overall device structure, offsetting the complexity introduced by the stacked configuration and making the device easier to manufacture.
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 solution enables a cost-effective, thinner OLED with improved luminance and reduced power consumption by allowing separate driving of each diode without compromising the aperture ratio.
Implementation Method 1
Holes from the anode and electrons from the cathode are combined within the organic light emitting layer to create hole-electron pairs, i.e., excitons. The OLED emits light by energy generated while the excitons return to ground state.
Data Source
Figure 1~2
Figure 3~4
AI summary
An organic light emitting display (OLED) includes a substrate (105), first (110A) and second (110B) driving units positioned on the substrate, a first light emitting diode (120;LED) connected with the first driving unit and including a first organic light emitting layer (140) and a second emitting diode (160) electrically connected (195) with the second driving unit and including a second organic light emitting layer (180). The second emitting diode (160) is positioned on the first emitting diode (120).