TFT Array Shield Lines Reduce Light Leakage and Short Risk
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Solution Overview
Problem
Conventional liquid crystal display (LCD) modules suffer from light leakage due to the absence of effective shielding between lead lines in the peripheral circuit region, leading to reduced yields and quality issues such as 'bright lines' caused by particle contamination or static discharge.
Innovation Solution
The implementation of shield lines made of first and second metal layers in the peripheral circuit region, overlapping with and electrically connected to source and gate lines, respectively, to prevent light leakage, with connection parts having narrower widths than gaps to minimize interference and allow for laser repair of shorts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If shield lines are added between lead lines to prevent light leakage, then light leakage is prevented, but the risk of short circuits between shield lines and lead lines increases due to particle contamination or static discharge
Solution Approach 1:
A non-conductive insulation layer is introduced between the shield line and the lead line. This intermediary layer prevents direct contact and short circuits between the shield line and lead line, while still allowing the shield line to fulfill its light-shielding function. The insulation layer acts as a mediator that eliminates the harmful effect of potential short circuits while preserving the beneficial light leakage prevention.
Solution Approach 2:
The shield line is divided into multiple segments with gaps between them, rather than being a continuous line. This segmentation reduces the total overlap area with lead lines, thereby reducing the risk of short circuits from particle contamination or static discharge, while still providing sufficient light shielding in the critical regions.
2Object-affected harmful factors
If shield lines overlap with lead lines to prevent light leakage, then light leakage is prevented, but manufacturing complexity increases due to additional alignment requirements
Solution Approach 1:
The shield line pattern is merged with the existing lead line pattern design. The shield lines are positioned to overlap with lead lines in a systematic way that can be integrated into the existing photolithography and patterning processes. This merging approach allows the shield lines to be formed using similar manufacturing steps as the lead lines, reducing the additional complexity of alignment and fabrication.
3Reliability
If the black matrix layer is shrunk towards the center to prevent contamination from non-uniform sealant curing, then contamination is prevented, but light leakage occurs at the junction between the black matrix layer and sealant
Solution Approach 1:
The shield line acts as an intermediary element that fills the gap between the black matrix layer and the sealant. By positioning the shield line in this region, it provides both mechanical support and optical shielding, preventing light from passing through gaps while maintaining the shrinked black matrix layer configuration that prevents contamination.
Data Source
AI summary
A thin film transistor array substrate is provided. A plurality of shield lines are disposed between the lead lines in a peripheral circuit region of the substrate. A connecting line connected to the shield lines is also disposed in peripheral circuit region of the substrate. The shield lines and the connecting line are formed of a metal layer so that light leakage between the lead lines of a source/drain layer or a gate layer is reduced. Furthermore, the line widths in the connecting portions of the shield lines connected to the connecting lines are smaller than the distance between the lead lines. Therefore, if a short happens between the lead lines and the shield lines, repair may be performed by cutting the connection portions between the shield lines and the connecting lines.