I stumbled across Immersion while Iwas doing a patent search for a haptic system not related to cell phones or video games.
They (or rather, he--the patents seem to originate from one person) file for zillions of patents, all nearly identical to one another, on "technologies" that seem blindingly obvious. One of them gets invalidated? Fifteen get invalidated? No problem, there's a thousand more behind them!
A patent for a haptic interface involving a video game controller containing a motor with a counterweight to create vibration. A patent for a haptic interface involving a video game controller containing two motors with counterweights to create vibration. A patent for a haptic interface involving a video game controller containing two motors with counterweights to create vibration, wherein said motors can be controlled separately. A patent for a haptic interface involving a video game controller containing two motors with counterweights to create vibration, wherein said motors can be controlled separately and are oriented differently. A patent for a haptic interface involving a video game controller containing two motors with counterweights to create vibration, wherein said motors are controlled by a single controller. You get the idea.
These guys are (this guy is?) the McDonald's of patent trolls, mass-producing zillions of low-quality patents on an assembly line basis to keep a constant flow of lawsuits in the pipeline. I keep waiting to see their logo changed to a giant stylized M with the slogan "Over 42 billion sued!"