OLED Color Adjustment via Switchable Liquid Crystal
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Solution Overview
Problem
Existing organic light-emitting diodes (OLEDs) that emit mixed colors, such as white light, require multiple separately contactable electrodes and complex layer structures, increasing production effort and limiting flexibility in color adjustment.
Innovation Solution
Incorporating a cholesteric liquid crystal element that can switch between reflecting and transmitting specific wavelength ranges, allowing for adjustable color emission without separate electrical activation of individual organic light-emitting layers, thereby reducing production complexity and enabling dynamic color temperature adjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple organic light-emitting layers are arranged with separate contactable electrodes for color adjustment, then color location adjustability is improved, but device complexity and production effort increase
Solution Approach 1:
A liquid crystal layer is introduced as an intermediary between the organic light-emitting layers and the observer. This liquid crystal layer can selectively reflect or transmit specific wavelength ranges depending on its switching state, thereby adjusting the perceived color location without requiring separate electrodes for each light-emitting layer. The liquid crystal layer acts as a mediator that modifies the output light based on electrical control signals.
Solution Approach 2:
The patent utilizes the ability of liquid crystals to change their optical properties (reflective vs. transparent) in response to electrical signals. By switching the liquid crystal layer between different states, the color composition of the emitted light is dynamically adjusted - when reflective, it enhances certain wavelengths; when transparent, it allows the full spectrum to pass through, thereby achieving color location adjustment without structural changes to the OLED itself.
2Adaptability or versatility
If multiple organic light-emitting layers are arranged with separate contactable electrodes for color adjustment, then color location adjustability is improved, but manufacturing complexity increases
Solution Approach 1:
The liquid crystal layer serves as a manufacturable intermediary component that can be integrated into existing OLED production processes. Instead of requiring complex multi-electrode structures that are difficult to manufacture, the solution adds a single liquid crystal layer that can be controlled by a unified electrode structure, significantly simplifying the manufacturing process while maintaining color adjustability.
Solution Approach 2:
The liquid crystal layer performs multiple functions: it acts as a wavelength-selective reflector, a color adjustment mechanism, and a controllable optical filter all in one component. This multi-functional element replaces what would otherwise require multiple separate electrode-controlled light-emitting layers, reducing manufacturing steps and improving ease of production.
3Ease of operation
If a liquid crystal element is used to adjust color location by reflecting light, then ease of operation is improved, but energy loss increases due to reflection
Solution Approach 1:
The liquid crystal layer is dynamically switchable between reflective and transparent states based on operational requirements. When color enhancement is needed, it reflects specific wavelengths; when energy efficiency is prioritized, it transitions to transparent mode to minimize reflection losses. This dynamic adaptability allows the system to optimize between ease of operation and energy efficiency depending on the application context.
Solution Approach 2:
The liquid crystal layer can be switched periodically between reflective and transparent states to achieve desired color adjustment while managing energy losses. By controlling the timing and duration of reflective states, the system can balance color adjustment needs against energy conservation, using reflection only when necessary for color location adjustment.
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
Enables efficient and energy-effective adjustment of color temperature and luminosity in OLEDs by selectively reflecting or transmitting light, reducing production effort and enhancing flexibility in color output without the need for separate electrical contact of multiple layers.
Implementation Method 1
the liquid crystal element in the first state is suitable for selectively reflecting light of a first wavelength range
Implementation Method 2
the liquid crystal element in the first state is suitable for selectively reflecting light of a first wavelength range
Implementation Method 3
in the second state with the focal conic texture, the cholesteric liquid crystal element is advantageously transparent
Implementation Method 4
a plurality of organic light-emitting layers for generating the mixed light. In such case, the plurality of organic light-emitting layers emit light in various wavelength ranges
Data Source
AI summary
An optoelectronic component and a method to operate the optoelectronic component are disclosed. In an embodiment the optoelectronic component includes an organic light-emitting diode configured to emit radiation through a main emission surface and a liquid crystal element configured to adjust a color location of the radiation, wherein the liquid crystal element is switchable into a first state and into a second state, wherein the liquid crystal element in the first state is suitable for selectively reflecting light of a first wavelength range and in the second state is transparent, and wherein the liquid crystal element is arranged on a rear side of the organic light-emitting diode facing the main emission surface so that light of the first wavelength range that is emitted towards the rear side is at least partially reflected in a direction of the main emission surface in the first state of the liquid crystal element.