TFT Substrate Terminal Line Width Adjustment for LCD Disconnection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Liquid crystal display devices face issues with signal line resistance variations and disconnection due to glass debris, leading to defects and manufacturing challenges, as existing techniques either fail to set uniform resistances or increase manufacturing costs.
Innovation Solution
The solution involves forming terminal portions as a unit with auxiliary lines and connection lines that have a width of 20 µm or more, allowing for uniform line resistances and preventing disconnection, while also adjusting line widths to prevent short-circuiting and ensure reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the intervals between terminals are set smaller than the intervals between scanning lines and data signal lines to match the standardized flexible printed circuit board, then the adaptability to standardized components is improved, but the resistance of scanning lines and data signal lines varies depending on position causing signal delay and distortion
Solution Approach 1:
The patent applies local quality by setting different line widths for connection lines at different positions. Specifically, connection lines at peripheral portions have larger widths than those at center portions, compensating for the longer transmission paths and higher resistance at peripheral areas. This localized adjustment ensures uniform resistance across all scanning lines and data signal lines while maintaining compatibility with standardized flexible printed circuit boards having smaller terminal intervals.
2Reliability
If the width of connection lines at peripheral portions is set larger than at center portions to equalize resistance, then the reliability of signal transmission is improved, but the complexity of line width adjustment increases
Solution Approach 1:
The patent implements local quality by differentiating connection line widths based on their position relative to the flexible printed circuit board. Connection lines connecting to peripheral terminals have larger widths to compensate for longer path lengths and higher resistance, while center connection lines have standard widths. This targeted approach equalizes overall resistance without requiring complete redesign of all connection lines, thus managing structural complexity.
3Reliability
If the width of auxiliary lines is set to 20 µm or more to prevent disconnection from glass debris, then the reliability against foreign material damage is improved, but the risk of short-circuiting between lines increases
Solution Approach 1:
The patent applies local quality by setting the width of auxiliary lines to 20 µm or more specifically in regions where they extend from terminal portions to connection lines, particularly in peripheral areas where glass debris contamination risk is higher during manufacturing. This localized thickening provides mechanical protection without causing short-circuits because auxiliary lines are positioned and dimensioned to maintain appropriate spacing from other conductive elements.
Solution Approach 2:
The auxiliary lines function as intermediary protective structures between the terminal portions and the main connection lines. These thick auxiliary lines (20 µm or more) act as protective conduits that shield the underlying connection lines from glass debris and other foreign materials during the manufacturing process, while their design ensures they do not create short-circuiting risks through proper spacing and positioning.
Data Source
Figure 1
Figure 2A~2B
Figure 3A~3B
AI summary
The present invention provides a technique which can prevent the disconnection of lines in the vicinity of terminal portions 100 formed on an end portion of a TFT substrate 10 of a liquid crystal display panel. Terminal portions 100 for supplying electric signals to scanning lines 11 are formed on a TFT substrate 10. Auxiliary lines 112 and connection lines 111 are formed between the terminal portions 100 and the scanning lines in order from the terminal portions 100. A line width of the auxiliary line 112 is set to 20 µm or more and the auxiliary lines 112 extend to a region where the TFT substrate 10 is covered with the color filter substrate 20. Although the connection lines 111 connect the auxiliary lines 112 and the scanning lines 11, for making the resistances from the terminal portions 100 uniform, a line width of the connection line 111 at a center portion of a flexible printed circuit board 30 is set to a small value and a line width of the connection line 111 at a peripheral portion of the flexible printed circuit board 30 is set to a large value. At the center portion of the flexible printed circuit board 30, the line width of the connection line 111 is set smaller than a line width of the auxiliary line 112. Due to such a constitution, it is possible to prevent the occurrence of the disconnection in the vicinity of the terminal portions 100 attributed to a glass debris or the like