An air filter device is installed on an exhaust device. The air filter device includes a filter net and one or more ultraviolet light-emitting diodes (UV LEDs). The filter net is disposed at an air passageway of the exhaust device. The UV LED is disposed on the exhaust device and located at one side...http://www.google.es/patents/US6797044?utm_source=gb-gplus-sharePatente US6797044 - Air filter device
