Electrochromic Substrate for White OLED Chromaticity Compensation
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Solution Overview
Problem
White OLEDs suffer from unstable chromaticity due to the short lifetime of blue luminescent materials, leading to yellowing of white light and reduced luminescence performance and lifetime.
Innovation Solution
A light emitting device with an electrochromic substrate, chromaticity instrument, processor, and driver that compensates for chromaticity by calculating and applying an electrical signal to the electrochromic substrate, using materials like WO3 or Prussian white, to maintain stable white light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If blue luminescent material is used in white OLED, then white light emission is achieved, but chromaticity stability deteriorates due to short lifetime of blue material
Solution Approach 1:
An electrochromic substrate is introduced as an intermediary component between the blue luminescent material and the viewer. This substrate dynamically adjusts its optical properties to compensate for the yellowing of white light, acting as a mediator that corrects the chromaticity drift caused by blue material degradation without requiring replacement of the blue luminescent material itself.
Solution Approach 2:
The electrochromic substrate utilizes color change properties by transitioning between different optical states (transparent and colored) in response to electrical signals. This allows the substrate to actively adjust the perceived chromaticity of the emitted white light, counteracting the yellowing effect and maintaining stable color appearance over time.
2Stability of the object's composition
If blue luminescent material decays, then white light turns yellow, but adding compensation system increases device complexity
Solution Approach 1:
The electrochromic substrate serves multiple functions simultaneously: it acts as a compensation layer for chromaticity stability, functions as an optical modulation element, and integrates with the existing OLED structure. This multi-functionality reduces the need for separate compensation components, thereby limiting the increase in device complexity while achieving chromaticity stabilization.
Solution Approach 2:
The system compensates for chromaticity drift by dynamically changing the optical parameters (absorption, transmission) of the electrochromic substrate through electrical control. This parameter change approach allows active compensation without requiring structural modifications to the blue luminescent material or fundamental changes to the OLED architecture.
3Stability of the object's composition
If electrochromic substrate is added for compensation, then chromaticity stability improves, but manufacturing complexity increases
Solution Approach 1:
The electrochromic substrate is pre-integrated into the OLED structure during the manufacturing process, positioned between the blue luminescent material and the viewer. This preliminary integration ensures that the compensation mechanism is already in place before the device is put into service, eliminating the need for post-manufacturing assembly or calibration steps and simplifying the overall manufacturing workflow.
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 real-time chromaticity compensation, ensuring stable and pure-white display, improving display quality and extending the service life of white OLEDs.
Implementation Method 1
an electrochromic substrate disposed on the second electrode... the driver is configured to drive the electrochromic substrate to emit light with the electrical signal, to compensate for the chromaticity of the light emitted by the light emitting device
Data Source
AI summary
The present disclosure provides a light emitting device and a display apparatus, The light emitting device includes a substrate, and a first electrode, a light emitting layer and a second electrode which are sequentially disposed on the substrate, an electrochromic substrate is disposed on the second electrode; the light emitting device further includes a chromaticity instrument, a processor, and a driver; the chromaticity instrument is configured to acquire chromaticity of light emitted by the light emitting device; the processor is configured to calculate compensated chromaticity for the light emitted by the light emitting device according to the chromaticity of the light emitted by the light emitting device acquired by the chromaticity instrument, and calculate an electrical signal according to the compensated chromaticity for the light emitted by the light emitting device.