容大感光：公司向胜宏科技供应的主要是PCB光刻胶系列产品

Group 1 - The core viewpoint of the article is that Rongda Photoelectric has commenced trial production of its photosensitive dry film production line at its Zhuhai production base, indicating a strategic expansion into this product market [1] - The company plans to strengthen its market development efforts for photosensitive dry film products while maintaining its sales in the PCB photoresist (liquid) market [1] - Shenghong Technology is identified as a major customer, with the company supplying primarily PCB photoresist products to Shenghong Technology, highlighting a stable and long-term cooperative relationship [1]