Patent ID: 7952817
Filing Date: 2011-05-31
Classification: G02B

Abstract:
1. A projection lens comprising: a first lens group comprising an aspheric lens with a negative refractive power; a second lens group comprising a first lens and a second lens, the first lens being disposed between the aspheric lens and the second lens, and refractive powers of the first lens and the second lens being negative; and a third lens group having a positive refractive power and comprising a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, an eighth lens, a ninth lens, a tenth lens, an eleventh lens, and a twelfth lens arranged in sequence, the third lens being disposed between the second lens and the fourth lens, and refractive powers of the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens, the tenth lens, the eleventh lens, and the twelfth lens being positive, negative, positive, negative, negative, positive, negative, positive, negative, and positive, respectively.