Patent ID: 7142365

Claim:
A condenser lens characterized by being composed of one or more optical lenses including an optical lens made of optical material selected among HfO 2 —Y 2 O 3 , HfO 2 —TiO 2 , HfO 2 —Sc 2 O 3 , HfO 2 —Nd 2 O 3 , HfO 2 -Ln 2 O 3 , Sc 2 O 3 , MgO, Y 2 O 3 , WO 3 , Gd 2 O 3 , Eu 2 O 3 , Dy 2 O 3 or mainly made of that optical material and wherein the condenser lens is composed of the optical lens made of said optical lens material and another optical lens and arranged with their optical axes aligned.