Variable Subpixel Opening Area for Blue OLED Deterioration
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Solution Overview
Problem
In existing organic EL displays, blue subpixels are thinned out, leading to increased current density and deterioration over time.
Innovation Solution
A display device configuration with island-shaped subpixels, where the blue and red subpixels have larger light-emitting regions and shared light emission control lines, reducing current density and suppressing deterioration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If blue subpixels are thinned out in the display, then the manufacturing complexity is reduced, but the current density of the blue light-emitting layer increases and deterioration occurs over time
Solution Approach 1:
The patent applies local quality by making the opening area in the cover film variable across different subpixels. Specifically, the opening area in blue subpixels is made larger than in red or green subpixels, allowing blue light-emitting layers to operate at lower current densities and reducing deterioration, while maintaining the thinned-out blue subpixel arrangement for manufacturing simplicity.
2Reliability
If the opening area exposing the first electrode is made larger in the first subpixel, then the current density is reduced and deterioration is suppressed, but the manufacturing precision requirements increase
Solution Approach 1:
The patent applies parameter changes by systematically varying the opening area parameter across different subpixel types. The cover film is designed with different opening areas corresponding to different subpixels (larger for blue, smaller for red/green), which allows control of current density through a geometric parameter that can be precisely controlled during the fabrication process.
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 by decreasing current density and minimizing black floating, thereby enhancing the display's longevity and quality.
Implementation Method 1
organic EL display
Data Source
AI summary
A display device includes a plurality of subpixels. The plurality of subpixels include a first subpixel including a first light-emitting layer, and a first subpixel circuit, a second subpixel including a second light-emitting layer, and a second subpixel circuit, a third subpixel including a third light-emitting layer, and a third subpixel circuit, and a fourth subpixel including a fourth light-emitting layer, and a fourth subpixel circuit. An area of an opening exposing a first electrode in the first subpixel is larger than an area of the opening exposing the first electrode in each of the second subpixel, the third subpixel, and the fourth subpixel. A plurality of light emission control lines include a first light emission control line connected to the first subpixel circuit and the third subpixel circuit, and a second emission control line connected to the second subpixel circuit and the fourth subpixel circuit.