Perry Mason as intellectual property attorney?

The Perry Mason episode The Case of the Tarnished Trademark [Season 5, episode 18] sounds in intellectual property, but, in fact, the plot line is a bit of a paradox. One has a Danish immigrant Axel Norstaad [played by Karl Swenson] who started a furniture factory, developed a reputation for high-quality goods, and thus created a valuable trademark. Wanting money to create a hospital, Axel sells the factory [and trademark rights] to Martin Somers [played by Dennis Patrick]. Martin has some cash flow problems. The paradox is that Martin immediately starts to make inferior goods under the tradename, and telegraphs that intent to the wholesalers [by the low prices], which causes the wholesalers to get back to Axel. For Martin's scheme to work, you don't let buyers know in advance that the product is inferior. Martin does get killed, but it is not about the trademark issue. Two other notable aspects of this episode. Axel's dismissive attitude toward Mason. The final interchange between Perry and Della, nominally about Axel and Edie, which is more about Perry and Della.

Della: Ah, such a pity that a man like that should have to wait all those years to get married. Don’t you agree?
Perry: You’ve been my legal secretary long enough to know that that’s a leading question.

In "The case of Gambling Lady" [Season 8, episode 26], there is an allusion to a [prior] patent infringement case done by Perry on behalf of client Peter Warren (played by actor Peter Breck), who owns a novelty game shop. The 1965 episode concerns casino chips. Were they counterfeited by Warren? For all the allegations of fake chips, it turns out they are all genuine and a different culprit is identified.