The subjects published by optical films are the most.

China, China is the world's largest source of optical film technology, and the number of optical film patent applications accounts for 44.72% of the total number of global optical film patent applications; Followed by Japan, the number of patent applications in the optical film industry in Japan accounts for 32.96% of the total patent applications in the global optical film industry; South Korea and the United States ranked third and fourth in the world respectively, and the number of patent applications in the optical film industry accounted for 10.80% and 6.02% of the total patent applications in the global optical film industry respectively.