A Shanghai company filed a lawsuit on Tuesday against the Beijing-based Patent Reexamination Board (PRB) of the State Intellectual Property Office (SIPO) over the patent authority's decision to validate the patent of the iPhone exterior design.

Shanghai Luoen Tech-info Ltd claimed the exterior design of the iPhone, a popular product of Apple Inc, is too similar to that of the DMB MP3 player created by LG and another two handset products (818 and 828+) created by Dopod, all of which had already got valid patents before Apple made the patent application.

Luoen Tech-info requested a reexamination by the PRB in November 2008. The PRB responded by maintaining the patent was valid in August 2009.