Auxiliary Electrode Structure for Compact Gate Driving Transistors
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Solution Overview
Problem
Conventional flat panel display devices, such as LCD and OLED, face challenges with gate signal output transistors that consume a significant area due to the need for increased capacitance, leading to potential short circuits and design constraints, especially in applications with limited space like notebook computers.
Innovation Solution
The design incorporates a driving apparatus with a control electrode, semiconductor layer, and auxiliary electrode, featuring interdigitated branches and a transparent conductive material, which enhances capacitance between the control and output electrodes while minimizing the area and reducing the risk of short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the gate and source are enlarged to provide broader overlap for sufficient capacitance, then the capacitance between gate and source is improved, but the transistor area is increased
Solution Approach 1:
The patent introduces a third dimension by forming an auxiliary electrode above the gate electrode through a hole in the insulating film. This vertical arrangement creates additional capacitance (between auxiliary electrode and gate electrode) without requiring increased lateral overlap area, thus resolving the contradiction between capacitance and area.
Solution Approach 2:
The auxiliary electrode is nested within the existing transistor structure by forming it through a hole in the insulating film above the gate electrode. This nested configuration adds capacitance functionality while utilizing the existing spatial footprint, avoiding area increase.
2Reliability
If the gate and source are enlarged to provide broader overlap for sufficient capacitance, then the capacitance between gate and source is improved, but the possibility of short circuit between source and gate is increased
Solution Approach 1:
Instead of increasing lateral overlap (which increases short circuit risk), the patent moves to the vertical dimension by placing the auxiliary electrode above the gate through an insulating film. This spatial separation in the vertical direction maintains electrical isolation while providing the needed capacitance.
Solution Approach 2:
The insulating film acts as an intermediary between the auxiliary electrode and the gate electrode. It allows capacitance formation while preventing direct electrical contact that would cause a short circuit, thus resolving the contradiction between capacitance and short circuit risk.
3Power
If the gate signal output transistor area is increased to provide sufficient power for signal transmission, then the power transmission capability is improved, but the available area for manufacturing seal process is reduced
Solution Approach 1:
The patent adds capacitance in the vertical dimension through the auxiliary electrode structure, which enables sufficient power transmission capability without increasing the lateral area of the transistor. This preserves the black matrix area needed for the seal process.
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 solution reduces the overall area required for the gate driving portion, enhances reliability, and simplifies transistor design by optimizing capacitance distribution, allowing for more efficient use of space in display devices.
Implementation Method 1
an auxiliary electrode formed on the second insulating layer, connected to the control electrode, and overlapped with the output electrode
Data Source
AI summary
In accordance with one or more embodiments of the present invention, a driving portion of a display device is formed on the same plane as a display portion of a display device. The driving portion includes cumulative layers of a control electrode, a first insulating layer, a semiconductor layer, a second insulating layer, an input electrode, an output electrode, and an auxiliary layer on top of the layers. Thus, the transistors within the driving portion may be more compact, while possibly reducing the likelihood of a short circuit between the electrodes.