Former Philadelphia Eagles safety Nate Allen isn't satisfied with having his name cleared after being accused of masturbating in public ... he plans on suing the cops that arrested him in the first place. Allen's lawyer, Sawyer Smith, tells TMZ Sports ... Allen wants to make sure no other citizens…

Philadelphia Eagles player Nate Allen was wrongly accused of driving around while pleasuring himself, and FL prosecutors have cleared his name -- partly due to a well-timed Red Lobster dinner. Allen was detained last week in Fort Myers after a 16-year-old girl called 911 to report seeing a man…