Thin Film Transistor Array Panel Peripheral Photosensitive Film
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Solution Overview
Problem
In liquid crystal displays, the thickness of the passivation layer can lead to increased contact hole height and width, making them susceptible to moisture and static electricity, and the photolithography process for patterning thin film transistors increases manufacturing costs.
Innovation Solution
A thin film transistor array panel with a substrate having a display area and a peripheral area, where the first insulating layer is formed on the gate and data lines, and a photosensitive film is used only in the peripheral area to control the contact hole height and prevent moisture and static electricity, while reducing manufacturing costs by minimizing the thickness of the passivation layer in the peripheral area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of the passivation layer is increased to protect the driving circuit unit from moisture or static electricity, then the protection capability is improved, but the height and width of the contact hole are increased making it more susceptible to moisture and static electricity
Solution Approach 1:
The passivation layer is segmented into different thickness regions: a first passivation layer with greater thickness for protection, and a second passivation layer with lesser thickness in the peripheral area. This segmentation allows different regions to serve different functions - protection in the display area and moisture blocking with reduced contact hole dimensions in the peripheral area.
Solution Approach 2:
The patent applies local quality by making the passivation layer thickness location-dependent. The first passivation layer covering the display area has greater thickness for protection, while the second passivation layer in the peripheral area has lesser thickness to reduce contact hole dimensions. This local differentiation resolves the contradiction between protection and susceptibility.
2Reliability
If the thickness of the passivation layer is increased to protect the driving circuit unit, then the protection capability is improved, but the manufacturing cost is increased due to additional photomasks
Solution Approach 1:
The patent merges the patterning of the first and second passivation layers into a single photolithography process. By forming both layers using one photomask, the manufacturing process is simplified and costs are reduced while still achieving the differentiated thickness structure needed for protection.
Solution Approach 2:
The single photomask serves multiple functions: it patterns both the first passivation layer and the second passivation layer with different thicknesses. This multi-functionality eliminates the need for separate photomasks, reducing manufacturing complexity and cost while maintaining the protective structure.
3Reliability
If the width of the contact hole is increased to expose the driving signal transfer lines, then the connection is improved, but the susceptibility to moisture or static electricity is increased
Solution Approach 1:
The contact hole structure is segmented vertically with the first contact hole exposing the driving signal transfer line for connection, while the second contact hole positioned above it blocks moisture and static electricity. This segmentation allows the contact hole to simultaneously provide electrical connection and environmental protection.
Solution Approach 2:
The second passivation layer acts as an intermediary element between the exposed driving signal transfer line and the external environment. It provides the necessary electrical connection through the first contact hole while blocking moisture and static electricity through the second contact hole structure.
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 protects the driving circuit unit from moisture and static electricity while reducing the manufacturing costs by controlling the contact hole height and width, thereby decreasing the inflow of moisture and static electricity and minimizing the thickness of the passivation layer in the peripheral area.
Implementation Method 1
a photolithography process may be used to pattern a thin film layer of a thin film transistor
Data Source
AI summary
Provided is a thin film transistor array panel. The thin film transistor array panel includes: an insulation substrate including a display area with a plurality of pixels and a peripheral area around the display area; a gate line and a data line positioned in the display area of the insulation substrate; a first driving signal transfer line and a second driving signal transfer line positioned in the peripheral area of the insulation substrate; a first insulating layer positioned on the gate line and the data line; and a first photosensitive film positioned on the first driving signal transfer line and the second driving signal transfer line, in which the first photosensitive film is disposed only in the peripheral area.