By Scott Flaherty

Law360, New York (January 20, 2012, 12:31 PM ET) -- Electronic gaming company WMS Gaming, Inc. sued competitor Aristocrat Technologies Inc. in Illinois federal court on Wednesday, alleging infringement of three slot machine patents.

The suit claims Aristocrat's Viridian Hybrid gaming machines — including the Winning Wishes, Zorrow, Ultra Spin and Stormin' Jackpot devices — have LCD screens overlaying mechanical slot machine reels that rely on "transmissive reels technology" patented by WMS, which allows for superimposing video images over mechanical reel slot machines and variable video displays, including touch-sensitive screens, on gaming machines.

Aristocrat's Viridian Hybrid...