Oxide Semiconductor Transistor Driving Voltage Range
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Solution Overview
Problem
High-resolution display devices face challenges in maintaining a wide range of driving voltages due to reduced driving current, which affects the performance of pixels, and existing transistors do not efficiently manage this requirement.
Innovation Solution
The display device incorporates a driving transistor with an active layer and an oxide layer that supplies oxygen to ensure a wide range of driving voltages, while the switching transistor has a different active layer and no oxide layer, with gate insulating layers positioned differently to enhance electron mobility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the number of pixels is increased to achieve high resolution, then the display resolution is improved, but the driving current of each pixel is reduced
Solution Approach 1:
The patent applies different transistor structures to different functional requirements within the same pixel circuit. The driving transistor uses an oxide semiconductor layer to maintain low threshold voltage and wide driving voltage range, while the switching transistor uses a non-oxide semiconductor layer for high electron mobility. This local differentiation of material properties allows each transistor to be optimized for its specific function despite the overall reduction in pixel driving current.
2Loss of energy
If the driving current is reduced due to increased pixel count, then the power consumption is reduced, but the driving voltage range becomes limited
Solution Approach 1:
The patent changes the material parameter of the semiconductor layer in the driving transistor from non-oxide to oxide semiconductor. This material parameter change fundamentally alters the electrical characteristics, enabling the transistor to maintain a low threshold voltage and wide driving voltage range even with reduced driving current, thus preserving adaptability while reducing power consumption.
3Device complexity
If the same transistor structure is used for both driving and switching functions, then the device complexity is reduced, but the performance of both transistors cannot be optimized
Solution Approach 1:
The patent segments the semiconductor layer into two distinct types: oxide semiconductor for the driving transistor and non-oxide semiconductor for the switching transistor. This segmentation allows each transistor type to have independently optimized material properties - the oxide layer provides low threshold voltage characteristics essential for driving, while the non-oxide layer provides high electron mobility essential for switching - thereby maintaining reliability without excessive complexity.
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 ensures a wider range of driving voltages for pixels and improves electron mobility in the switching transistor, addressing the limitations of existing technologies in high-resolution displays.
Implementation Method 1
an oxide layer having an oxide semiconductor... capable of supplying oxygen to the active layer
Data Source
AI summary
A display device includes a substrate, a buffer layer disposed on the substrate, a first semiconductor layer disposed on the buffer layer and including an oxide semiconductor and a first active layer, a first gate insulating layer disposed on the first semiconductor layer and the buffer layer, a second semiconductor layer disposed on the first gate insulating layer and including an oxide semiconductor, a second active layer, and a first oxide layer on the first active layer, a second gate insulating layer disposed on the second semiconductor layer, a first conductive layer disposed on the second gate insulating layer, an insulating layer disposed on the first conductive layer, a second conductive layer disposed on the insulating layer, a passivation layer disposed on the second conductive layer, and a third conductive layer disposed on the first passivation layer.