Organic EL Display Panel with Blue Light Conversion Layers
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Solution Overview
Problem
Existing organic EL display panels face challenges in improving luminous efficiency and productivity, particularly with blue organic EL elements having the shortest operating life, and the shadow mask method leads to material loss and increased costs.
Innovation Solution
The organic EL display panel incorporates a substrate with barrier ribs and pixel electrodes for red, green, and blue subpixels, featuring a charge generation layer and a second blue organic light-emitting layer that converts blue light to red and green light, eliminating the need for a shadow mask and enhancing material utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the shadow mask method is used to form blue light-emitting layers, then manufacturing precision can be improved, but material loss increases and productivity decreases
Solution Approach 1:
The patent removes the shadow mask component from the deposition system, transitioning from a shadow mask-based patterning method to a direct deposition method. This extraction eliminates material loss associated with mask usage while maintaining manufacturing precision through alternative alignment approaches.
Solution Approach 2:
The patent introduces a barrier rib structure as an intermediary element that defines pixel regions and guides material deposition. This barrier rib serves as a physical mediator that replaces the shadow mask's function of defining deposition patterns, enabling direct deposition without material loss to masks.
2Use of energy by moving object
If blue light-emitting elements are used to improve display performance, then luminous efficiency increases, but operating life decreases
Solution Approach 1:
The patent divides the blue light-emitting function into multiple segments by stacking two or more blue light-emitting layers. This segmentation distributes the operational stress across multiple layers, reducing the burden on individual layers and thereby extending the overall operating life while maintaining high luminous efficiency.
Solution Approach 2:
The patent transitions from a single-layer blue light-emitting structure to a multi-layer stacked structure, adding the vertical dimension to the design. This dimensional change allows multiple blue light-emitting layers to contribute to the overall light output, improving luminous efficiency while sharing the operational load to extend operating life.
3Manufacturing precision
If multiple deposition methods are used to form different light-emitting layers, then manufacturing precision improves, but device complexity increases
Solution Approach 1:
The patent employs a universal deposition process that can form multiple types of light-emitting layers (red, green, blue) using the same deposition method and equipment. This multi-functional approach eliminates the need for separate specialized processes for each layer type, reducing manufacturing complexity while maintaining precision.
Solution Approach 2:
The patent merges the deposition processes for different colored light-emitting layers into a unified process flow. By combining the formation of red, green, and blue light-emitting layers into a single integrated deposition sequence, the patent reduces the number of separate manufacturing steps and simplifies the overall process while maintaining layer formation precision.
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 structure improves luminous efficiency and productivity by converting blue light to red and green light, reducing material loss, and lowering production costs, while extending the operating life of blue organic EL elements.
Implementation Method 1
a first light conversion layer that is disposed above the second blue organic light-emitting layer in the red subpixel region, and converts blue light to red light
Implementation Method 2
a second light conversion layer that is disposed above the second blue organic light-emitting layer in the green subpixel region, and converts blue light to green light
Implementation Method 3
When the organic light-emitting elements are driven, voltage is applied between each anode and the cathode, and holes and electrons injected to the light-emitting layer recombine with each other, and thus the organic light-emitting elements emit light
Data Source
AI summary
An organic EL display panel includes: a first pixel electrode and a red organic light-emitting layer sequentially disposed in red subpixel region; a second pixel electrode and a green organic light-emitting layer sequentially disposed in green subpixel region; a third pixel electrode and a first blue organic light-emitting layer sequentially disposed in blue subpixel region; a charge generation layer disposed above the red, green, and first blue light-emitting layers; a second blue organic light-emitting layer disposed on the charge generation layer in the entire subpixel regions; a counter electrode disposed above the second blue light-emitting layer in the entire subpixels regions; a first light conversion layer disposed above the second blue light-emitting layer in the red subpixel region, and converts blue light to red light; and a second light conversion layer disposed above the second blue light-emitting layer in the green subpixel region, and converts blue light to green light.