http://www.scientificamerican.com/article.cfm?id=patent-watch-apr-11
Patent No. 7,866,082
http://www.genesis-illumination.com/Applications/StunRay.html
Incapacitating light beam: The suspect is going for his gun, and the police officer doesn’t want to shoot. The founders of a company called Genesis Illumination hope police officers will soon be reaching for a StunRay instead of a gun or Taser. They claim their newly patented device can render an assailant helpless with a brief flash of high-intensity light. It works by overloading the neural networks connected to the retina, saturating the target’s world in a blinding pool of white light. “It’s the inverse of blindness—the technical term is a loss of contrast sensitivity,” says Todd Eisenberg, the engineer who invented the device. “The typical response is for the person to freeze. Law enforcement can easily walk up and apprehend [the suspect].”
The device consists of a 75-watt lamp, combined with optics that collect and focus the visible light into a targeted beam, which can be aimed like a flashlight. Recovery time ranges from “seconds to 20 minutes,” Eisenberg says. “It’s very analogous to walking from a very bright room into a very dark room.”
The inventors say the StunRay has a number of advantages over taser guns, which work best within a range of 12 to 15 feet. The StunRay can be effective from as far away as 150 feet. And whereas Tasers can cause cardiac arrest, the StunRay is reasonably safe. One downside is that the target must be facing the light for it to work. But “if the target has turned and is running away, the objectives of stopping an aggressive behavior or avoiding a potentially lethal confrontation have still been met,” Eisenberg notes.