Dual-Gate Oxide Transistor for Display Luminance Uniformity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Active-matrix display devices with light-emitting elements face challenges in achieving high resolution and aperture ratio due to variation in threshold voltage among driving transistors, which affects luminance and light emission, especially in bottom-emission structures where transistors block light.
Innovation Solution
A display device configuration that includes a transistor with overlapping gates, capacitors, and light-emitting elements, where the transistor has a channel formation region with an oxide semiconductor, and dual-gate driving is employed to correct threshold voltage variations, enhancing the on-state current and reducing transistor area, thereby increasing resolution and aperture ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pixel includes a large number of transistors for threshold voltage correction, then luminance variation is suppressed, but device complexity increases and resolution decreases
Solution Approach 1:
The invention extracts the threshold voltage correction function from the main driving transistor by introducing a separate correction transistor. This allows the correction function to be implemented with minimal additional components rather than requiring multiple transistors within the same pixel, thereby suppressing luminance variation while maintaining low device complexity and high resolution
Solution Approach 2:
The invention introduces a correction transistor as an intermediary element that mediates between the driving transistor and the light-emitting element. This correction transistor specifically addresses threshold voltage variations without requiring the driving transistor itself to be overly complex, thus achieving luminance uniformity while keeping the pixel structure simple
2Reliability
If transistors are added for threshold voltage correction, then luminance variation is suppressed, but aperture ratio decreases due to light blocking
Solution Approach 1:
The correction function is extracted and implemented in a separate correction transistor rather than expanding the area of transistors within the pixel. This separation allows threshold voltage correction to be achieved with minimal impact on the light-emitting area, thus maintaining a high aperture ratio while suppressing luminance variation
Solution Approach 2:
The invention implements the correction transistor in a different spatial arrangement or layer dimension, allowing it to perform threshold voltage correction without occupying additional area that would block light in bottom-emission structures. This dimensional separation preserves the aperture ratio while achieving luminance uniformity
3Manufacturing precision
If transistor area is reduced to increase resolution, then high resolution is achieved, but threshold voltage variation control becomes more difficult
Solution Approach 1:
The correction transistor serves as an intermediary that compensates for threshold voltage variations in the driving transistor. This allows the driving transistor to be miniaturized for high resolution while the correction transistor handles the threshold voltage control, thus achieving both high resolution and reliable threshold voltage control
Solution Approach 2:
The threshold voltage control function is extracted from the miniaturized driving transistor and assigned to a separate correction transistor. This extraction allows the driving transistor to be made small for high resolution without sacrificing threshold voltage control capability, as the correction transistor handles this function independently
Data Source
AI summary
A display device includes a transistor including first and second gates. A first terminal of the transistor is electrically connected to a third wiring. A first switch controls electrical connection between a first wiring and the first gate. A second switch controls electrical connection between a second wiring and the second gate. A third switch controls electrical connection between the first gate and a second terminal of the transistor. A fourth switch controls electrical connection between a fifth wiring and the second terminal of the transistor. A first capacitor retains a potential difference between the first gate and the second terminal of the transistor. A second capacitor retains a potential difference between the first gate and the second gate. A first terminal of the light-emitting element is electrically connected to the second terminal of the transistor. A second terminal of the light-emitting element is electrically connected to a fourth wiring.