First off this is tedious digging for someone like myself who is not at all versed in processors and chips.  My interest in digging was the link FS2006 posted about a Matsushita - ARM relationship.

http://www.agoracom.com/ir/patriot/message/532850

Matsushita has used ARM for sometime now and has had success with some of their processors.

What I found in the documents you supplied was only one match between the two.  ARM's, ARM7TDMI is the core of Matsushita's MN1A7T0200 chip.  Which I deduct has been very successful for Matsushita. TPL/PTSC claim this chip infringes on the 336 and the 584 patent.

What I found that was of more interest is (my deduction only) that Matsushita is responsible for many, many other chips on their own.  I would also deduct this is why the chip manufacturing division of Matsushita is still involved in the court case.  If you recall, TPL/ PTSC offers two types of licensing. One for users of chips and one for manufacturers of them. I'm guesing ARM and Matsushita's chip manufacturing  division are still in court fighting the type of license AMD and Intel purchased that is for chip designers/producers.