Bi-Stable Light Control Element for OLED Efficiency
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Solution Overview
Problem
Organic light-emitting diodes (OLEDs) have low light extraction efficiency due to optical refraction differences between layers, resulting in only 15% to 20% of light emitting into the air without optical compensation, limiting their application in display and illumination.
Innovation Solution
Incorporating a bi-stable light control element under the OLED, which can change its optical state in response to a control signal to modulate light extraction efficiency and transmittance, allowing for increased light emission through the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If an optical diffusion film is disposed at the bottom surface of the transparent substrate to enhance light extraction efficiency, then the light extraction efficiency is improved, but the device structure becomes more complex and the manufacturing process becomes more difficult
Solution Approach 1:
The patent introduces a bi-stable light control element as an intermediary component between the OLED and the external environment. This element acts as a mediator that can dynamically adjust the optical path, enabling light to be extracted from both the top and bottom surfaces of the OLED structure, thereby improving overall light extraction efficiency without requiring complex diffusion films or microlens arrays
Solution Approach 2:
The bi-stable light control element provides dynamic control over light extraction by switching between two stable optical states. This dynamic capability allows the system to optimize light extraction efficiency in real-time based on operational requirements, replacing static optical compensation structures with a more flexible and adaptable solution
2Productivity
If the OLED is designed for high light extraction efficiency, then more light can emit into the air, but the transmittance of the device decreases
Solution Approach 1:
The bi-stable light control element enables dynamic switching between two operational modes: in the first stable state, the element allows external light to pass through, maintaining high transmittance; in the second stable state, the element directs emitted light toward the top surface, maximizing light extraction efficiency. This dynamic adaptability resolves the contradiction between transmittance and light extraction efficiency
Solution Approach 2:
The system changes the optical parameters of the light control element by applying different voltages to switch between stable states. By controlling the voltage applied to the bi-stable element, the system can adjust its optical properties to prioritize either transmittance or light extraction efficiency based on the specific application requirements
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 bi-stable light control element enhances light extraction efficiency and transmittance by either allowing external light to pass through or concentrating emitted light, improving the overall performance of OLEDs.
Implementation Method 1
The bi-stable light control element is configured to change an optical state of the bi-stable light control element according to a received control signal
Implementation Method 2
When the organic light-emitting diode is supplied with a specific voltage, electrons and electron-holes are combined to each other and emit lights
Implementation Method 3
because the organic light-emitting layer 14 has an optical refraction greater than that of the transparent substrate 16, the light 121 with a relatively large emission angle in the transparent conductive layer 14 is totally reflected back
Data Source
AI summary
An organic light-emitting device includes a first transparent substrate, an organic light-emitting diode and a bi-stable light control element. The organic light-emitting diode is disposed under the first transparent substrate. The bi-stable light control element is disposed under the organic light-emitting diode. The bi-stable light control element is configured to change an optical state thereof according to a received control signal and thereby changing the amount of lights capable of emitting through the bi-stable light control element. A control method for the aforementioned organic light-emitting device is also provided.