Display Fan-Out Wire Layout for Uniform Luminance and Low Dead Space
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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 during manufacturing.
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 reduce resistance differences and ensure uniform luminance, and a photomask with slits to enhance resolution and prevent defects during etching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the fan-out wire has a uniform width, then the manufacturing process is simple, but the resistance varies due to different path lengths causing non-uniform luminance
Solution Approach 1:
The fan-out wire is designed with varying widths along its length, where the width is larger at portions closer to the display area and smaller at portions farther away. This local variation in width compensates for the resistance differences caused by path length variations, ensuring uniform current distribution and uniform luminance across the display area.
Solution Approach 2:
The wire width parameter is changed along the length of the fan-out wire to compensate for resistance variations. By adjusting the width parameter locally, the resistance per unit length is modified to achieve uniform current flow despite different path lengths, thereby maintaining uniform luminance.
2Area of stationary object
If the fan-out wire path is shortened to reduce dead space, then the device area is reduced, but the resistance increases causing luminance non-uniformity
Solution Approach 1:
The fan-out wire incorporates local width variations where the width is increased at specific segments to compensate for resistance. This allows the wire to maintain a shorter overall path (reducing dead space) while still achieving uniform resistance distribution through local width adjustments, thereby maintaining luminance uniformity.
3Stability of the object's composition
If the fan-out wire width is increased to reduce resistance, then the luminance uniformity improves, but the dead space and device area increase
Solution Approach 1:
Instead of uniformly increasing the wire width, the design applies local width increases only at specific segments where resistance compensation is needed. This localized approach reduces the overall dead space and device area while still achieving the goal of uniform luminance through targeted resistance adjustment.
4Productivity
If the fan-out wiring pattern uses tight spacing to maximize display area, then the productivity increases, but defects such as open-circuits and short-circuits occur during manufacturing
Solution Approach 1:
The photomask design incorporates local width variations that correspond to the fan-out wire geometry. By matching the photomask features to the desired wire width profile, the manufacturing process achieves higher precision in forming tight-spaced wires, reducing defects while maintaining high display area utilization.
Solution Approach 2:
The patent uses a photomask with specifically designed geometric features to define the fan-out wire pattern during the photolithography process. This replaces mechanical wire formation methods with a precision optical patterning approach, enabling tighter spacing with reduced defects.
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.