Key technologies to manufacture advanced flat-panel displays at Samsung Mobile Display and LG Display have been leaked by an local unit of an Israeli company, local prosecutors said Wednesday, raising concerns the leakage could pose a major threat to the national interest.

The Seoul Central District Prosecutors' Office indicted under physical detention three employees at the local unit of an Israeli inspection equipment supplier, including a 36-year-old man surnamed Kim, on charges of leaking key local technologies used to produce active-matrix organic light-emitting diode (AMOLED) displays and white organic light-emitting diode (White OLED) displays.

They also indicted without physical detention three other employees and the local unit, the prosecutors said, without identifying the Israeli firm.

According to the prosecution, the indicted employees photographed circuit diagrams of yet-to-be-released 55-inch AMOLED television panels when they were let into Samsung and LG's manufacturing factories to check defects of inspection equipment from November of last year to January of this year.

They stored the images on portable memory cards and slipped them into their shoes, belts and wallets to avoid suspicion,

prosecutors said.

AMOLED displays have a faster response time then their passive-matrix OLED counterparts and are more power-efficient, and the advantages make them well suited for growingly popular portable electronics devices. Samsung and LG are by far the leading makers of AMOLED displays, for which the global market is estimated to be worth 90 trillion won (US$77.8 billion). South Korea rigorously prohibits leakage of the technologies as it tags them as the nation's core industrially strategic tech.

Prosecutors said the stolen information was likely relayed to the Israeli headquarters and Chinese and Taiwanese display-making rivals, including the biggest Chinese panel manufacturer BOE.

"It is very likely that the stolen technologies have been given by the Israeli firm to foreign rivals," a prosecution official said. "This may expectedly deal a massive economic blow to the entire nation and can cause a sea change in the landscape of the global display market."

According to industry watchers, Samsung spent nearly 1.4 trillion won in developing its AMOLED technologies with LG funneling nearly 1.3 trillion won into its research and development.

Prosecutors pledged to launch a probe into the Israeli headquarters to prevent further tech leakages. (Yonhap News)