One of Apple's iPhone screen suppliers LG Display said on Tuesday that it would invest three trillion won (2.6 billion U.S. dollars) in its organic light-emitting diode (OLED) panels production line in South Korea, according to Reuters.

Until September 2018, Samsung was Apple's sole OLED screen supplier.

LG Display, that invests heavily in OLED panels at a time of weak demand for smartphones and tech gadgets in general, said in a statement it would continue to expand its lead in the OLED TV market.

After Japan tightened export regulations over several chemicals used in chip and smartphone production amid disputes on wartime forced labor, the two South Korean tech giants are facing divergent paths ahead.

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LG Display will be less vulnerable than Samsung Display since the latter is much more dependent on the materials imported from Japan.

Besides, LG Display will begin mass production of OLED panels for large TVs at its plant in Guangzhou, south China's Guangdong Province, this August, which was approved two years ago. 

The factory will be responsible for the front end of line manufacturing, said the company, while the back end of line manufacturing, like assembly, will be moved to Vietnam.

"All etching gas used in the production process of large-size OLED panels is supplied by companies in China," an LG Display official told Business Korea. "We do not use etching gas from Japan, so we are not affected by Japan's export restrictions."

The South Korean firm is scheduled to report its second-quarter earnings later on Tuesday.