Transistor Channel Conductive Layer for LCD Peripheral Circuit Reliability
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Solution Overview
Problem
Existing liquid crystal display devices do not adequately address the issue of transistor malfunctions in peripheral circuits, which are prone to frequent malfunctions due to prolonged operation, leading to display unevenness and reduced display quality, especially in automotive navigation and mobile devices.
Innovation Solution
A liquid crystal display device with a first substrate and a second substrate facing each other, featuring a display area with a matrix of pixels and a frame edge area containing a peripheral circuit with transistors, where the channel area of the transistors is covered by a conductive layer through an inorganic insulating layer, and a negative potential is applied to the conductive layer to prevent threshold voltage shifts and reduce malfunctions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If transistors in peripheral circuits operate for prolonged periods to drive display pixels, then display functionality is maintained, but transistor malfunctions increase due to threshold voltage shifts
Solution Approach 1:
A conductive layer is formed over the channel area of the transistor before operation, with a work function difference that preliminarily adjusts the threshold voltage. This preliminary action compensates for expected threshold voltage shifts that occur during prolonged operation, maintaining transistor reliability without requiring continuous monitoring or adjustment during operation.
Solution Approach 2:
The threshold voltage of the transistor is modified by changing the work function of the conductive layer relative to the semiconductor layer. This parameter change in the energy band structure compensates for threshold voltage shifts caused by prolonged operation, thereby improving transistor reliability over extended operation periods.
2Reliability
If no additional conductive layer is added to peripheral circuit transistors, then device complexity remains low, but display unevenness occurs due to transistor malfunctions
Solution Approach 1:
The conductive layer is selectively formed only over the channel area of transistors in the peripheral circuit region, not throughout the entire display device. This local application provides targeted compensation for transistor malfunctions in the peripheral circuit while minimizing additional device complexity and avoiding unnecessary modifications in other regions.
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
The solution effectively reduces transistor malfunctions in peripheral circuits, improving display quality and reducing display unevenness, thereby enhancing the operational reliability and performance of liquid crystal display devices in various electronic apparatuses.
Implementation Method 1
a channel area of the transistor is covered with a conductive layer via an inorganic insulating layer... and a predetermined negative potential is applied to the conductive layer
Data Source
AI summary
A liquid crystal display device including a first substrate, a second substrate disposed so as to face the first substrate and a liquid crystal layer disposed between the first and the second substrates, the first substrate including: a display area portion in which a plurality of pixels are arranged in a manner of a matrix; and a frame edge area lying outside the display area portion, the frame edge area including a peripheral circuit configured to drive the plurality of pixels of the display area portion, the peripheral circuit having at least one transistor, wherein a channel area of the transistor is covered with a conductive layer via an inorganic insulating layer, the inorganic insulating layer and the conductive layer being stacked in a direction orthogonal to a surface of the first substrate in the stated order, and a predetermined negative potential is applied to the conductive layer.