The lawsuit, filed this week by Triton Tech of Texas, names both Apple and Nintendo as defendants. Triton is the owner of U.S. Patent No. 5,181,181, entitled "Computer Apparatus Input Device for Three-Dimensional Information."
That patent describes a handheld device that includes multiple accelerometers and angular rate sensors for detecting positioning and motion. By interpreting acceleration, velocity and relative position of the device, it can allow users to interact with a computer or other device with six degrees of motion in a three-dimensional space.
Illustrations that accompany the patent show a mouse with three buttons, and the filing specifically mentions a "mouse" that senses motion in six axes.
Triton's lawsuit only specifically singles out the iPhone 4 from Apple as an infringing device, though it implies that other devices could be in violation. Apple's iPod touch and iPad also include accelerometers that are used for input.
The iPhone 4 also includes a new gyroscope that is not yet found in other iOS-based mobile devices. The gyroscope allows for even more precise motion-based controls, particularly in games available on the App Store.
The suit asserts that the iPhone 4 is in violation because the hardware is "using acceleration sensors and rotational rate sensors for detecting motion about a particular axis for communication with a computing device." It notes that Apple's handset accomplishes this task without approval or licensing from Triton.
Also named in the lawsuit is the Nintendo Wii Motion Plus gaming accessory, which allows users to experience even more precise input via an attachment to the Wii remote control.
The complaint was filed Monday in a U.S. District Court in the Eastern District of Texas. Patent lawsuits are often filed there in hopes of a favorable outcome.