Fan-out Lead Impedance Matching via Variable Width
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Solution Overview
Problem
In flat panel display technology, the unequal lengths of fan-out leads result in inconsistent impedances, leading to display unevenness and increased non-effective display region area, which hinders narrow frame design and utilization of array substrates.
Innovation Solution
The array substrate design features fan-out leads with first and second metal strip portions on a glass substrate, where the lengths of the first metal strip portions are gradually increased from the center to the edge, and the number of these portions is decreased, with insulation and passivation layers incorporating through holes to ensure consistent impedances without the need for winding, thus maintaining equal line widths and distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the width of each fan-out lead is kept equal, then the manufacturing process is simplified, but the impedances of fan-out leads at the central portion are lower than those at the edge portion, causing signal synchronization issues
Solution Approach 1:
The patent applies local quality by varying the width of fan-out leads according to their position. Central fan-out leads have smaller widths while edge fan-out leads have larger widths, creating localized structural differences that compensate for the inherent impedance variations caused by different path lengths from the chip
Solution Approach 2:
The patent changes the geometric parameter (width) of fan-out leads to adjust their electrical impedance. By modifying the width parameter of leads at different positions, the patent achieves consistent impedance values across all fan-out leads, ensuring proper signal synchronization
2Reliability
If the lengths of all fan-out leads are made equal by winding, then impedance consistency is achieved, but the height of the fan-out leads increases and the non-effective display region area expands
Solution Approach 1:
Instead of changing the length parameter through winding, the patent changes the width parameter of fan-out leads to achieve impedance consistency. This allows leads to maintain equal lengths without winding, thereby reducing height and minimizing the non-effective display region area
Solution Approach 2:
The patent inverts the conventional approach by not making lengths equal through winding, but instead making widths different to achieve the same impedance consistency goal. This inverted strategy eliminates the need for winding and reduces the non-effective region area
3Area of stationary object
If the lengths of fan-out leads are increased from center to edge, then the non-effective display region area is reduced, but the impedances of fan-out leads become inconsistent
Solution Approach 1:
The patent applies local quality by assigning different widths to fan-out leads at different positions. Leads at the center have smaller widths while leads at the edge have larger widths, creating localized structural variations that compensate for the length differences and achieve consistent impedance values
Solution Approach 2:
The patent changes the width parameter of fan-out leads to adjust their impedance values. By systematically varying the width parameter across different positions, the patent achieves impedance consistency while maintaining the optimized length distribution that reduces the non-effective display region area
Data Source
AI summary
A method for manufacturing an array substrate includes a step of forming a first metal layer on a glass substrate such that the first metal layer includes multiple first metal lines distributed as a fan shape, each of the first metal lines including a predetermined number of first metal strip portions that are spaced from each other and have an equal length; forming an insulation layer on the multiple first metal lines in such a way that portions of the insulation layer respectively covering the first metal strip portions are each provided with a first through hole and a second through hole formed therein; and forming a second metal layer on the insulation layer such that the second metal layer includes multiple second metal strip portions respectively in contact with the first metal strip portions of the first metal lines via the first through holes and the second through holes.