Display Signal Pad Layout for Narrower Fan-Out Bezels
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Solution Overview
Problem
The challenge of reducing the width of the fan-out area in display panels is limited by the increasing number of fan-out lines and driving integrated circuits, leading to constraints on bezel width and potential contact failures between signal pads and terminals.
Innovation Solution
The display panel design features signal pads that gradually increase in length and decrease in width outwardly from a central portion, with fan-out lines extending diagonally or in a zigzag pattern to reduce the fan-out area width and prevent contact failures, even in large display devices with multiple driving integrated circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of fan-out lines connected to one driving integrated circuit increases, then the display device can support more pixels and larger display areas, but the width of the fan-out area cannot be reduced sufficiently, leading to increased dead space
Solution Approach 1:
The signal pads are designed with non-uniform dimensions where pads farther from the display area have larger lengths and smaller widths. This local variation in pad geometry allows fan-out lines to be more closely spaced without increasing the overall fan-out area width, thereby reducing dead space while accommodating increased line density
Solution Approach 2:
The signal pads exhibit asymmetric dimensional changes along the arrangement direction, with each successive pad having different length and width characteristics. This asymmetric design optimizes the spatial distribution of fan-out lines, enabling narrower bezel by reducing the horizontal span of the fan-out area
2Area of stationary object
If the width of the fan-out area is reduced to minimize dead space, then the bezel width can be narrowed, but contact failure between signal pads and signal terminals may occur
Solution Approach 1:
Signal pads at different positions have optimized local dimensions - pads farther from the display area have larger lengths providing extended contact areas. This compensates for alignment tolerances and prevents contact failure even when the overall fan-out area width is reduced
Solution Approach 2:
The length and width parameters of signal pads are systematically varied based on their position in the array. By changing these geometric parameters, the design achieves both compact fan-out area width and sufficient contact reliability through enlarged pad dimensions at critical locations
3Area of stationary object
If signal pads are arranged closer together to reduce dead space, then the fan-out area width can be minimized, but manufacturing precision requirements increase to prevent contact failure
Solution Approach 1:
Signal pads with larger lengths at farther positions provide increased overlap areas with corresponding signal terminals. This local enlargement creates a tolerance buffer that reduces sensitivity to alignment errors, thereby lowering manufacturing precision requirements despite closer pad spacing
Solution Approach 2:
The design incorporates enlarged pad dimensions in advance to compensate for potential alignment deviations. By providing larger contact areas beforehand, the design cushions against manufacturing variations and prevents contact failure without requiring extremely tight tolerances
Data Source
AI summary
A display panel includes: a display substrate including a display area and a pad area spaced apart from a side of the display area in a first direction; and first to (n)th signal pads (where n is an integer of 2 or more) in the pad area on the display substrate, extending in the first direction, and spaced apart from each other in a second direction perpendicular to the first direction, wherein a (k)th signal pad among the first to (n)th signal pads (where k is an integer between 1 and n) is between the first signal pad and the (n)th signal pad, wherein a length of each of (k)th to (n)th signal pads among the first to (n)th signal pads along the first direction gradually increases, and wherein a width of each of the (k)th to (n)th signal pads along the second direction gradually decreases.