Aside from mention that the case is being fought over "trademark infringement", there really isn't much information in the court filings detailing the legal battle between Sony and Jerry Lambert, the actor who for years has played the fictional PlayStation executive Kevin Butler.
A Sony statement issued today, however, casts a little more light on SCEA's reasons for filing the suit. Speaking with Kotaku, a PlayStation representative says:
Sony Computer Entertainment America filed a law suit against Bridgestone and Wildcat Creek, Inc. on September 11. The claims are based on violations of the Lanham Act, misappropriation, breach of contract and tortious interference with a contractual relationship. We invested significant resources in bringing the Kevin Butler character to life and he's become an iconic personality directly associated with PlayStation products over the years. Use of the Kevin Butler character to sell products other than those from PlayStation misappropriates Sony's intellectual property, creates confusion in the market and causes damage to Sony.
As it's a legal matter, the company won't be discussing the matter further. We have yet to hear from Bridgestone, another of the targeted parties, on the matter.