Organic EL Display Blue Subpixel Area Optimization
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Solution Overview
Problem
In existing organic electroluminescent (EL) display devices, blue subpixels are prone to deterioration due to increased current density, leading to susceptibility issues over time.
Innovation Solution
A display device configuration featuring a first light emitting layer for blue light, a second light emitting layer for red light, and a third light emitting layer for green light, with the blue light emitting layer having a larger surface area than the red and green light emitting layers, arranged in a specific island shape and diagonal configuration between electrode layers to reduce current density and prevent deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If blue subpixels are thinned to increase current density, then luminance output is improved, but susceptibility to deterioration over time increases
Solution Approach 1:
The patent applies local quality by giving the blue light emitting layer a larger surface area compared to red and green light emitting layers. This localized differentiation allows the blue layer to maintain lower current density while other layers have different area characteristics, resolving the contradiction between luminance output and deterioration susceptibility for blue subpixels
Solution Approach 2:
The patent changes the surface area parameter of the blue light emitting layer relative to red and green layers. By adjusting this physical parameter, the current density distribution is modified, allowing the blue layer to achieve adequate luminance without the harmful effects of excessive current density that would accelerate deterioration
2Reliability
If the surface area of blue light emitting layer is increased, then current density is reduced and deterioration is prevented, but device area increases
Solution Approach 1:
The patent implements local quality by differentiating the surface areas of different colored light emitting layers within the same device. The blue layer is specifically enlarged while red and green layers maintain their original dimensions, allowing targeted improvement of blue layer reliability without proportionally increasing the entire device area
Solution Approach 2:
The patent applies asymmetry by creating unequal surface areas among light emitting layers of different colors. The blue light emitting layer is intentionally made larger than red and green layers, breaking the symmetry of equal-sized subpixels to achieve optimized current density distribution and reduced deterioration for the blue channel
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 configuration effectively reduces the deterioration of the blue light emitting layer while maintaining the performance of red and green light emitting layers, enhancing the longevity of the display device.
Implementation Method 1
an organic electroluminescent (EL) device in which red, blue, and green subpixels form a delta arrangement
Data Source
AI summary
Provided is a display device including a first light emitting layer having an island shape, a second light emitting layer having an island shape, and a third light emitting layer having an island shape, between a lower electrode layer and an upper electrode layer. The first light emitting layer and the second light emitting layer are adjacent in a column direction, and the third light emitting layer is adjacent to the first light emitting layer and the second light emitting layer in a diagonal direction. The first light emitting layer emits blue light, one of the second light emitting layer and the third light emitting layer emits red light, and the other emits green light. A light emitting region of the first light emitting layer is larger than light emitting regions of the second light emitting layer and the third light emitting layer.