Flexible Printed Wiring Exposure Layout to Prevent Step Formation

The patent applies preliminary action by pre-designing the light-transmitting portion with a tapered shape before exposure. The tapered configuration is built into the photomask structure in advance, so that when the photomask is shifted during exposure, the tapered edges naturally guide the photoresist exposure boundaries, preventing the formation of angular portions and steps without requiring additional alignment adjustments.

The patent changes the geometric parameters of the light-transmitting portion by transitioning from a rectangular shape to a tapered shape. This parameter change modifies the exposure boundaries dynamically during the shifting process, allowing the front end to smoothly transition into the rear end region while maintaining precise wiring pattern formation and preventing step formation.

The tapered shape is pre-designed into the light-transmitting portion to prevent step formation before the exposure process begins. This preliminary geometric configuration ensures that even when the photomask is shifted, the exposure boundaries will naturally follow the tapered edges, creating smooth transitions in the wiring pattern that eliminate stress concentration points and enhance wiring durability.

The patent applies curvature by using a tapered shape with sloped edges instead of sharp angular corners. The tapered configuration creates a gradual, curved transition between the front and rear ends of the light-transmitting region, which prevents the formation of angular portions and steps on the wiring side, thereby reducing stress concentration and improving reliability.

The tapered light-transmitting portion is prepared in advance to prevent step formation before exposure. This preliminary geometric design ensures that the wiring pattern will have smooth transitions without sharp corners or steps, eliminating stress concentration points that would otherwise cause damage when the substrate is bent, thereby maintaining wiring strength throughout the manufacturing process.

The patent employs curvature through the tapered shape design, which replaces sharp angular transitions with smooth sloped edges. This curved geometry prevents stress concentration at angular portions and steps, allowing the exposure process to proceed while maintaining wiring strength and preventing potential damage during bending operations.