The local patent fight between Samsung Display and LG Display is escalating after Samsung’s filing of a lawsuit against its rival was discovered earlier this week.

LG Display said on Thursday that it will protest against Samsung’s move to file a suit against the firm on Dec. 7 for infringing on its liquid-crystal display patents.

“LG Display has led the development of the In-Plane Switching technology display technology ever since the beginning, which is why we find it difficult to understand the reason Samsung went ahead with raising a suit that claims LG infringed its imitating Plane-to-Line Switching technology,” said LG officials.

LG officials further elaborated that it was a pity that Samsung was expanding the fight against its local rival from organic light-emitting diode display technology to LCDs, hampering business with the litigations.

It emerged on Wednesday that Samsung filed a lawsuit with the Seoul Central District Court, asking the court to invalidate seven LG patents that allegedly copied Samsung’s PLS display technology without paying royalties.

It also requested a manufacturing and sales ban on LG products that infringed its patents, which include LG Electronics’ latest flagship smartphone Optimus G, as well as 2 billion won ($1.86 million) in compensation.

The event came after LG Display filed a lawsuit against Samsung, claiming that the competitor’s latest gadgets such as the Galaxy S3 infringed on seven of its patents for OLED technology in September.

The seven patented technologies include those on the OLED narrow bezel, OLED heating and OLED panel power outlet wiring structure, and the gadgets in dispute are Samsung’s Galaxy S2, S3, Note and Tab 7.7.

By Cho Ji-hyun (sharon@heraldcorp.com)