A Hitachi subsidiary filed a patent infringement lawsuit against LG Electronics and its subsidiary LG Electronics USA this week, alleging LG's plasma display panel products infringe on seven Hitachi patents.

Hitachi Plasma Patent Licensing filed the lawsuit in the U.S. District Court for the Eastern District of Texas on Monday. HPPL owns and manages Hitachi's patent portfolio.

The company said it's seeking compensation for monetary damages and a permanent injunction to stop imports, sales, and use of the disputed display panel products.

Hitachi said it has been in talks with LG Electronics representatives regarding licenses for the products, but the two parties reached an impasse.

LG Electronics representatives didn't immediately respond to calls for comment.

The LG subsidiary bills itself as the world's largest flat panel manufacturer, a leader in plasma development and production, and a founding member of the Plasma Display Coalition. Its 2007 plasma line features 10 models, ranging from 42 to 71 inches.

LG boasts of ranking first in quantity of production of CDMA handsets, home air conditioners, plasma panels, optical storage products, DVD players, and home theater systems. The company employs more than 70,000 people and has 80 subsidiaries around the globe.

Hitachi is also one of four members of the Plasma Display Coalition, which explains that most plasma screens work in similar ways. Hitachi employs about 356,000 people worldwide.

The Plasma Display Coalition reported a record 140% increase in sales during the holiday season last year, and said the industry is poised for continued growth this year.