Pixel Circuit Oxide Transistor Placement for Display Resolution
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Solution Overview
Problem
In display devices supporting variable frequency driving, a high ratio of oxide thin film transistors reduces the capacitance of capacitors within pixels, limiting pixel-per-inch (ppi) and thus reducing the display panel's resolution.
Innovation Solution
The number of oxide thin film transistors in the pixel is minimized by positioning at least one oxide thin film transistor between polysilicon thin film transistors and capacitors, increasing the capacitance and ppi, thereby enhancing the display panel's resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a high ratio of oxide thin film transistors is used in the pixel, then the pixel can support variable frequency driving, but the capacitance of the capacitor inside the pixel decreases and the resolution of the display panel is reduced
Solution Approach 1:
The patent applies local quality by using different transistor types in different locations within the pixel circuit. Specifically, oxide thin film transistors are used for switching functions where low leakage is critical, while polysilicon thin film transistors are used for driving functions where high current capability is needed. This localized differentiation allows the pixel to achieve variable frequency driving capability while maintaining sufficient capacitance for high resolution display.
2Adaptability or versatility
If a high ratio of oxide thin film transistors is used in the pixel, then the pixel can support variable frequency driving, but the pixel-per-inch (ppi) is limited and the resolution of the display panel is reduced
Solution Approach 1:
The patent changes the parameters of the transistor configuration by adjusting the ratio and types of transistors used in the pixel circuit. By optimizing the combination of oxide and polysilicon thin film transistors, the circuit can operate across variable frequencies while maintaining the physical dimensions required for high pixel-per-inch density. This parameter optimization enables both variable frequency driving and high resolution without compromising ppi.
Data Source
AI summary
A pixel may include a light emitting element; a data write transistor that writes a data voltage; a driving transistor that applies a driving current to the light emitting element based on the data voltage; a hold capacitor including a first electrode to which a first power supply voltage is applied, and a second electrode electrically connected to a first node; a storage capacitor including a first electrode electrically connected to the first node, and a second electrode electrically connected to a control electrode of the driving transistor; at least one polysilicon thin film transistor; and at least one oxide thin film transistor. The at least one oxide thin film transistor may be disposed between the at least one polysilicon thin film transistor and the hold capacitor, or between the at least one polysilicon thin film transistor and the storage capacitor.