Variable Color Electroluminescent Device Using Segmented Materials
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Solution Overview
Problem
Existing electroluminescent devices that emit white light struggle to vary their color point without requiring complex and costly control mechanisms or structured electrodes, making them undesirable for applications like room-lighting and display back-lighting.
Innovation Solution
An electroluminescent device with two regions of different electroluminescent materials, where the operating voltage is adjusted to change the relative luminance of each region, allowing the color point to be shifted by varying the voltage or current, and using a control unit to set the desired color point and luminance independently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple individually driven light-emitting regions with different spectral bands are used to vary color point, then the color point can be changed, but the device complexity and production cost increase due to structured electrodes and individual driving requirements
Solution Approach 1:
The light-emitting layer is divided into multiple regions with different electroluminescent materials having different luminance-voltage characteristics. Each region emits light in different spectral bands, and by independently controlling the voltage applied to each region, the color point of the emitted light can be varied without requiring structured electrodes or complex feedback systems.
Solution Approach 2:
The invention exploits the different luminance-voltage characteristics of electroluminescent materials to vary the color point by changing the applied voltage parameter. By selecting materials with appropriate luminance-voltage characteristics and adjusting the voltage, the relative contribution of each spectral band can be controlled, enabling color point variation without complex control systems.
2Adaptability or versatility
If multiple individually driven light-emitting regions with different spectral bands are used to vary color point, then the color point can be changed, but the production cost increases due to structured electrodes and additional techniques
Solution Approach 1:
The light-emitting layer is segmented into regions with different electroluminescent materials, each having distinct luminance-voltage characteristics. This segmentation allows color point variation through material properties rather than requiring complex electrode structuring, thereby reducing manufacturing complexity and cost.
Solution Approach 2:
By utilizing the inherent luminance-voltage characteristics of different electroluminescent materials and controlling the applied voltage parameter, the invention achieves color point variation without requiring costly structured electrodes or additional manufacturing techniques, thus improving ease of manufacture.
3Device complexity
If a single light-emitting layer with fixed material composition is used, then the device structure is simple, but the color point cannot be changed
Solution Approach 1:
The light-emitting layer is divided into multiple regions, each containing a different electroluminescent material with distinct luminance-voltage characteristics. This segmentation maintains relative structural simplicity while enabling color point variation through the different electrical characteristics of the materials rather than requiring complex physical structures.
Solution Approach 2:
The invention uses electroluminescent materials with different luminance-voltage characteristics in different regions of the light-emitting layer. By changing the applied voltage parameter, the relative luminance of each region can be adjusted, enabling color point variation while maintaining a simple overall device structure without requiring complex electrode configurations.
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 the electroluminescent device to produce white light with a variable color point without the need for complex control systems or structured electrodes, reducing production costs and complexity while allowing for easy adjustment of color and brightness.
Implementation Method 1
an electroluminescent device for emitting light (7), having a variable color point
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
An electroluminescent device (9) for emitting light (7) whose color point is able to be set variably, comprising at least two electroluminescent regions (41, 42) that, to allow the same operating voltage to be applied, are arranged to be connected in parallel electrically, wherein the electroluminescent regions (41, 42) comprise - at least one first electroluminescent region (41) of a first electroluminescent material for emitting light in a first spectral band in accordance with a first luminance vs. voltage characteristic (81), and - at least one second electroluminescent region (42) of a second electroluminescent material for emitting light in a second spectral band that is not the same as the first spectral band, in accordance with a second luminance vs. voltage characteristic (82) that is not the same as the first luminance vs. voltage characteristic (81).