Pixel Circuit Layout for Stable Grayscale in Inorganic LED Displays
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing display devices using inorganic light emitting diodes face image quality deterioration due to inconsistent driving methods, which are not compatible with organic light emitting diodes, leading to suboptimal grayscale and luminance control.
Innovation Solution
The display device enhances pixel circuit integration density by reducing contact holes and signal lines through a novel transistor configuration, utilizing low-temperature polysilicon-based and oxide-based semiconductor layers for transistors, and shared connection electrodes for data and emission lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional pixel circuit configuration is used, then the circuit can drive the light emitting element, but the integration density is low due to the large number of contact holes and signal lines required
Solution Approach 1:
The patent merges multiple signal lines by making the data line extend through multiple pixel circuits (first, second, and third pixel circuits) to share common connection electrodes. Specifically, the data line is configured to extend in the first direction and share connection electrodes with adjacent pixel circuits, reducing the total number of contact holes and signal lines required while maintaining proper electrical connections for driving the light emitting elements.
2Device complexity
If inorganic light emitting diodes are driven with the same method as organic light emitting diodes, then the driving circuit is simplified, but image quality deteriorates due to inconsistent grayscale and luminance control
Solution Approach 1:
The patent applies different transistor types in different locations within the pixel circuit to optimize performance for specific functions. The first transistor (controlling control current) and fourth transistor (controlling driving current) use low-temperature polysilicon-based semiconductor layers for high mobility and precise current control, while the second, third, fifth, and sixth transistors use oxide-based semiconductor layers for low leakage current. This local differentiation enables precise grayscale and luminance control while maintaining a relatively simple driving circuit structure.
Data Source
AI summary
A display device includes a data line, and first, second, and third pixels electrically connected to the data line. Each of the first, second, and third pixels includes a light emitting element, a first transistor that controls a control current, a second transistor that electrically connects the data line to a second node, which is a first electrode of the first transistor, a third transistor that electrically connects the first node to a third node, which is a second electrode of the first transistor, a fourth transistor that controls a driving current, which is supplied to the light emitting element, and a fifth transistor that electrically connects the data line to a fifth node, which is a first electrode of the fourth transistor. The data line is electrically connected to the fifth transistor of each of the first and second pixels through a connection electrode.