Patent ID: 8270069

Claim:
A UV light generator for receiving a baseband light beam from a baseband light source, comprising: a first lens unit, wherein the baseband light beam from the baseband light source passes through the first lens unit; a second lens unit; a first frequency doubling crystal, disposed between the first lens unit and the second lens unit, and located on the minimum of baseband light spot position, wherein the baseband light beam passes through the first frequency doubling crystal to become a second harmonic light beam, wherein the first lens unit and the second lens unit control a minimum of baseband light spot position of the baseband light beam and a minimum of second harmonic light spot position of the second harmonic light beam; and a second frequency doubling crystal, disposed between the first lens unit and the second lens unit, and located on the minimum of second harmonic light spot position, wherein the first lens unit comprises a baseband transparent film, a second harmonic reflective film and a fourth harmonic reflective film, wherein the first lens unit has a baseband focal length to the baseband light beam, the first lens unit has a second harmonic focal length to the second harmonic light beam, and the baseband focal length is greater than the second harmonic focal length, wherein the second lens unit has a baseband focal length to the baseband light beam, the second lens unit has a second harmonic focal length to the second harmonic light beam, and the baseband focal length is smaller than the second harmonic focal length, wherein the second lens unit comprises a baseband reflective film, a second harmonic reflective film and a fourth harmonic transparent film.