Oxide Semiconductor Transistor Driving Voltage Range
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Solution Overview
Problem
High-resolution display devices face challenges in maintaining adequate driving voltage ranges for pixels due to decreased driving currents, which can impact the performance of transistors in these devices.
Innovation Solution
Incorporating a driving transistor with an oxide layer and a switching transistor having the same oxide semiconductor material, where the oxide semiconductor includes indium, gallium, zinc, tin, or hafnium, to enhance the mobility and characteristics of the transistors, thereby maintaining a wide driving voltage range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of pixels is increased to achieve high-resolution display, then the display resolution is improved, but the driving current of each pixel decreases
Solution Approach 1:
The patent changes the material parameter of the transistor by using oxide semiconductor (such as In-Ga-Zn-O) instead of conventional semiconductor materials. This material substitution fundamentally alters the electrical characteristics, enabling high mobility even at reduced current levels, thus resolving the contradiction between high resolution and low driving current
2Measurement precision
If the driving current of each pixel is decreased to increase the number of pixels, then the display resolution is improved, but the driving voltage range is reduced
Solution Approach 1:
The patent changes the material parameter by employing oxide semiconductor with inherently high carrier mobility. This enables the transistor to operate effectively over a wide voltage range even when driven by low current, thus maintaining adequate driving voltage range despite the current reduction necessitated by high pixel density
Solution Approach 2:
The patent uses composite oxide semiconductor materials (such as In-Ga-Zn-O systems) that combine multiple elements to achieve optimized electrical properties. This composite approach allows tuning of the material characteristics to simultaneously achieve high mobility and wide operating voltage range under low current conditions
3Ease of manufacture
If conventional transistor materials are used in high-resolution displays, then the manufacturing process is simple, but the transistor characteristics deteriorate due to reduced driving current
Solution Approach 1:
The patent changes the material parameter to oxide semiconductor, which can be deposited using sputtering techniques that are relatively compatible with existing manufacturing processes. While the material itself is advanced, the deposition methodology maintains ease of manufacture while dramatically improving transistor characteristics for low-current operation
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 improves the characteristics of the driving transistor, ensuring a secure wide range of driving voltage for the light emitting elements, even in high-resolution displays, by using the oxide layer as an oxygen supply layer to inject excess oxygen into the channel region.
Implementation Method 1
using the oxide layer as an oxygen supply layer to inject excess oxygen into the channel region
Data Source
AI summary
A display device, includes: a pixel connected to a scan line and a data line crossing the scan line, wherein the pixel includes a light emitting element, a driving transistor configured to control a driving current supplied to the light emitting element according to a data voltage received from the data line, and a first switching transistor configured to apply the data voltage of the data line to the driving transistor according to a scan signal applied to the scan line; wherein the driving transistor includes a first active layer including an oxide semiconductor and a first oxide layer on the first active layer and including an oxide semiconductor; and wherein the first switching transistor includes a second active layer on the first active layer and including the same oxide semiconductor as the first oxide layer.