OLED Pixel Stack Layout for Longer-Lifespan Color Displays
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Solution Overview
Problem
Organic light emitting display devices have limited lifespan due to the weakest subpixel failing, leading to impaired image quality and reduced device lifespan, as they typically consist of three subpixels (red, green, blue) where the lifespan is determined by the first failing subpixel.
Innovation Solution
The device employs a stack structure with two subpixels, each comprising a hole only device (HOD) and an electron only device (EOD) structure, where red and green light emitting elements are stacked to form HOD and EOD structures respectively, allowing for differential voltage application to selectively emit light, thereby extending the lifespan by utilizing a failover system and optimizing blue light emitting diode size for longer durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If three subpixels (red, green, blue) are used in a unit pixel, then color display capability is improved, but device lifespan is reduced because the lifespan is determined by the weakest subpixel
Solution Approach 1:
The invention divides the unit pixel into two separate subpixels instead of three, with each subpixel containing stacked red and green light emitting elements. This segmentation reduces the number of independent failure points while maintaining color display capability through the stacked structure.
Solution Approach 2:
The invention implements a stacked structure where red and green light emitting elements are nested within each subpixel. This allows multiple color functions to be integrated into fewer subpixel units, so that failure of one stack does not compromise the entire pixel's operation.
2Duration of action of stationary object
If red and green light emitting elements are stacked to form HOD and EOD structures, then device lifespan is extended through failover system, but device complexity increases
Solution Approach 1:
The invention merges red and green light emitting elements into a single stacked structure within each subpixel. This combining approach achieves failover functionality where if one element fails, the other can still operate, extending device lifespan without requiring separate independent subpixels for each color.
Solution Approach 2:
The invention transitions from a planar arrangement of separate subpixels to a vertical stacked structure. By organizing light emitting elements in the vertical dimension (stacked layers), the patent achieves failover capability while reducing the horizontal footprint and simplifying the overall pixel structure.
3Duration of action of stationary object
If blue light emitting diode size is optimized for longer durability, then lifespan is extended, but brightness or area may be compromised
Solution Approach 1:
The invention optimizes the size parameter of the blue light emitting diode to balance durability and brightness. By carefully selecting the blue LED dimensions, the patent extends its operational lifespan while maintaining sufficient brightness output, resolving the trade-off between size/durability and illumination intensity.
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 enhances resolution, allows for longer device lifespan by differential driving of light emitting layers, and extends the lifespan of the blue light emitting diode, enabling the display device to emit red, green, blue, and white colors effectively.
Implementation Method 1
an organic light emitting display device uses an organic light emitting diode, which is a self-luminous element configured to emit light from a light emitting material layer thereof through re-combination of an electron and a hole
Data Source
AI summary
An organic light emitting display device can include a display panel including a plurality of data lines and a plurality of scan lines intersecting each other, and unit pixels disposed in a matrix arrangement, each of the unit pixels being disposed in a region where one scan line intersects three data lines; a data driving circuit configured to drive the plurality of data lines; and a gate driving circuit configured to drive the plurality of gate lines. Also, each of the unit pixels comprises two subpixels, and each of the two subpixels has a structure in which red, green and blue light emitting elements are stacked.