Top-Emitting OLED Color Conversion via Selective Thermal Transfer
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Solution Overview
Problem
Existing electroluminescent devices face challenges in achieving full color displays due to difficulties in patterning red-, green-, and blue-emitting primary OLED materials, and the use of color conversion techniques in traditional bottom emitting devices is limited by parallax problems and alignment issues, leading to reduced color saturation.
Innovation Solution
The implementation of selective thermal transfer techniques, such as Laser Induced Thermal Imaging (LITI), for forming color conversion elements on top emitting electroluminescent devices directly on the top electrode or a protective layer, or on the substrate surface opposite the electroluminescent element, allowing for more precise control and elimination of parallax issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If color conversion elements are placed on a separate piece of glass or substrate in traditional bottom emitting devices, then the device construction is simplified, but parallax problems occur and color saturation is reduced
Solution Approach 1:
The patent transitions from bottom emitting to top emitting device architecture, fundamentally changing the spatial dimension of light emission. By emitting light from the top surface rather than the bottom, the device eliminates the parallax effect that occurs when color conversion elements are separated from the light emitting layer, thereby maintaining color saturation while simplifying construction.
Solution Approach 2:
The patent inverts the traditional bottom emitting architecture to a top emitting configuration. This inversion allows the color conversion elements to be in direct optical association with the light emitting layer, eliminating alignment issues and parallax problems while maintaining manufacturing simplicity.
2Manufacturing precision
If red-, green-, and blue-emitting primary OLED materials are patterned to achieve full color displays, then color accuracy is improved, but patterning difficulty increases significantly
Solution Approach 1:
The patent extracts the color conversion function from the electroluminescent materials themselves and places it in separate color conversion elements. Instead of patterning multiple primary OLED materials, a single narrow-band emitting material is used in conjunction with color conversion elements that convert the emitted light to the desired colors, dramatically simplifying the patterning process while maintaining color accuracy.
Solution Approach 2:
The patent introduces color conversion elements as intermediary components between the narrow-band light emitting layer and the final displayed colors. These elements act as mediators that convert the emitted light to the desired color spectrum, eliminating the need to directly pattern multiple primary materials while achieving full color display capability.
3Manufacturing precision
If top emitting electroluminescent devices are used with color conversion elements on the top electrode, then alignment precision and color saturation are improved, but device complexity increases
Solution Approach 1:
The patent merges the color conversion elements directly onto the top electrode or protective layer of the top emitting device. This integration eliminates the need for separate alignment processes and reduces the distance between the light emitting layer and color conversion elements, improving alignment precision and color saturation while avoiding the complexity of separate component assemblies.
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 approach enhances color saturation and flexibility in pixel control, is compatible with organic electroluminescent device materials, and allows for reversible patterning without damaging the electroluminescent element, improving the overall performance of electroluminescent displays.
Implementation Method 1
selective thermal transfer (e.g., Laser Induced Thermal Imaging (LITI)) of color conversion elements
Implementation Method 2
selective thermal transfer (e.g., Laser Induced Thermal Imaging (LITI)) of color conversion elements for use in electroluminescent devices
Data Source
AI summary
An electroluminescent device, and a method of making an electroluminescent device that includes one or more color conversion elements is disclosed. In one embodiment, the method includes forming an electroluminescent element on a substrate, where the electroluminescent element is capable of emitting light in a narrow band. The method further includes selectively thermally transferring a plurality of color conversion elements to the electroluminescent element. In another embodiment, the method includes forming an electroluminescent element on a substrate, where the electroluminescent element is capable of emitting UV light. The method further includes selectively thermally transferring a plurality of color conversion elements to the electroluminescent element.