Display Fan-Out Wiring Layout for Uniform Luminance and Fine Pitch
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Solution Overview
Problem
Display devices face challenges in maintaining uniform luminance and minimizing dead space, while also preventing defects such as open-circuits and short-circuits in fan-out wiring patterns, particularly due to the complexity of fan-out wire configurations and the limitations of existing photomask technologies.
Innovation Solution
The design incorporates a substrate with specific zigzag and straight portions in fan-out wires, where the width and length of these portions are strategically adjusted to minimize resistance differences and prevent defects, along with a photomask featuring a blocking portion with a slit to enhance resolution and prevent disconnection during etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If fan-out wires are made with uniform width, then manufacturing is simple, but resistance differences cause non-uniform luminance
Solution Approach 1:
The fan-out wires are designed with different widths at different locations: wider in the first direction (to reduce resistance for longer paths) and narrower in the second direction. This local variation in wire width compensates for resistance differences across the display panel, achieving uniform luminance without excessive complexity.
2Illumination intensity
If fan-out wires are made wider to reduce resistance, then luminance uniformity improves, but dead space increases
Solution Approach 1:
Instead of uniformly increasing wire width across all fan-out wires, the patent applies width variation locally: wires are wider only where needed (in the first direction) to compensate for resistance, and maintain standard width elsewhere. This targeted approach reduces dead space while achieving luminance uniformity.
3Area of stationary object
If photomask pattern is made finer to reduce dead space, then manufacturing precision improves, but defects like open-circuits and short-circuits increase
Solution Approach 1:
The photomask is designed with pre-compensated features: wider patterns for fan-out wires in the first direction and included angles greater than 90 degrees at wire intersections. These preliminary design adjustments ensure that after manufacturing tolerances are applied, the final wire dimensions and spacing remain adequate, preventing open-circuits and short-circuits while maintaining fine pitch.
4Area of stationary object
If fan-out wires are placed closer together to reduce dead space, then area utilization improves, but short-circuit defects increase
Solution Approach 1:
The patent varies the spacing between fan-out wires locally based on position: wires are spaced more widely where resistance compensation is needed (with wider wire widths) and can be placed closer together where standard dimensions suffice. This selective spacing reduces overall dead space while maintaining adequate isolation to prevent short-circuits.
Data Source
AI summary
A display device includes: a substrate having a display area and a peripheral area; a first wiring layer to transfer a gate signal in the display area; a second wiring layer to transfer a data voltage in the display area; a data fan-out having a first data fan-out wire connected to the second wiring layer; and a data flexible printed circuit board electrically connected to the first data fan-out wire in the peripheral area. The first data fan-out wire includes a first zigzag portion having a zigzag shape and a first straight portion that extends from the first zigzag portion. A width of the first straight portion is larger than a width of the first zigzag portion.