Oxide TFT Driver-on-Panel Layout for High-Definition Displays
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Solution Overview
Problem
The increasing definition of display devices leads to a higher number of pixels, gate lines, and signal lines, making it difficult to mount IC chips for driver circuits, thereby increasing manufacturing costs. Additionally, high contact resistance between wirings distorts input signals, and there is a need to reduce the number of contact holes and the area occupied by the driver circuit.
Innovation Solution
The use of inverted staggered thin film transistors with oxide semiconductors on the same substrate for both the pixel portion and the driver circuit, where the thin film transistors include oxide semiconductor layers and channel protective layers. This configuration reduces manufacturing costs and minimizes contact resistance and the number of contact holes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the definition of display device is increased, then the number of pixels is increased, but it becomes difficult to mount IC chip having driver circuit
Solution Approach 1:
The patent merges the driver circuit and pixel portion onto the same substrate, eliminating the need for separate IC chip mounting. The driver circuit is formed using thin film transistors integrated with the pixel portion, thereby simplifying the overall device structure and reducing manufacturing complexity despite higher definition requirements.
2Measurement precision
If the number of gate lines and signal lines is increased, then the definition is improved, but manufacturing cost increases
Solution Approach 1:
The driver circuit is integrated directly on the substrate with the pixel portion, eliminating the need for separate IC chip mounting processes. This integration reduces manufacturing steps and costs, making it economically feasible to achieve high definition with increased numbers of gate lines and signal lines.
Solution Approach 2:
The patent uses thin film transistors formed by sputtering methods with low-cost materials and processes, replacing expensive crystalline silicon-based transistors that require laser annealing. This approach significantly reduces manufacturing costs while maintaining the capability to handle high-definition requirements.
3Reliability
If contact resistance between wirings is high, then signal distortion occurs, but reducing contact holes increases device area
Solution Approach 1:
The patent changes the electrical parameters of the oxide semiconductor material to achieve extremely low off-state current and optimized carrier concentration. This allows for reduced contact hole dimensions while maintaining low contact resistance, thereby reducing the overall driver circuit area without compromising signal quality.
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 approach reduces manufacturing costs, minimizes contact resistance, and decreases the number of contact holes and the area occupied by the driver circuit, resulting in a display device with high electrical properties and reliability.
Implementation Method 1
The oxide semiconductor film can be formed by a sputtering method or the like at a temperature lower than or equal to 300° C.
Data Source
AI summary
A pixel portion and a driver circuit driving the pixel portion are formed over the same substrate. At least a part of the driver circuit is formed using an inverted staggered thin film transistor in which an oxide semiconductor layer is used and a channel protective layer is provided over the oxide semiconductor layer serving as a channel formation region which is overlapped with the gate electrode. The driver circuit as well as the pixel portion is provided over the same substrate to reduce manufacturing costs.