Touch Substrate Joint Exposure for Mura Reduction

The patent divides the large-size touch substrate manufacturing into multiple exposure processes using the same mask plate. The mask plate is used to expose multiple regions of the substrate in sequence, with each exposure forming electrode patterns in a specific region. This segmentation allows the use of a single, manageable mask plate to create patterns across a large substrate area, reducing the complexity of handling and manufacturing multiple different mask plates.

The patent makes the mask plate universal by using it for multiple exposure processes on the same substrate. The mask plate is not discarded after a single use but is reused to expose different regions of the substrate in subsequent steps. This multi-functionality reduces the need for multiple specialized mask plates, thereby lowering manufacturing costs while still enabling large-size display area production.

The patent applies local quality by using positive photoresist in the repeated exposure area to specifically address the joint region, while using negative photoresist in non-repeated exposure areas. The positive photoresist in the repeated exposure area ensures that the joint regions receive proper exposure and develop uniformly, preventing the joint mura phenomenon. This localized differentiation of photoresist types allows precise control over the quality of different regions, particularly the critical joint areas, thereby improving overall display uniformity.