Hong says his Graphene Square Inc. has a patent that can make sheets of the material as large as 50 inches diagonally, about five times the length of an Apple iPad.

The conductive film now most commonly used for mobile-device touch screens, indium tin oxide or ITO, is too brittle for bendable displays and isn’t durable or effective enough on devices larger than 10 inches, said Lee Sung Chul, an analyst at Shinyoung Securities Co. in Seoul.

Hong’s patents are “key in making cost-efficient, large-scale graphene for touchscreen panels in mass volume.”

said Whang Dong Mok, a professor at the School of Advanced Materials Science & Engineering at Sungkyunkwan University in Suwon, South Korea, who predicts wearable devices using the material may arrive on the market within five years.