| 摘要 |
A projection optical system, which is disposed in an optical path between a first object and a second object and which projects an image of the first object onto the second object, comprises: a first lens group which is disposed in the optical path between the first object and the second object; a second lens group which is disposed in the optical path between the first object and the second object; a third lens group which is disposed in an optical path between the second lens group and the second object; a fourth lens group which is disposed in an optical path between the second lens group and the second; and a fifth lens group which is disposed in an optical path between the third lens group and the second object; the first lens group having a positive refracting power and at least two positive lenses, the second lens group having a negative refractive power and at least two negative lenses, the third lens group having a positive refractive power and at least three positive lenses, the fourth lens group having a negative refractive power and at least three negative lenses, and the fifth lens group having a positive refractive power and a negative lens of a biconcave shape, a first positive lens which is disposed as adjacent to the negative lens of biconcave shape on the first object side and shaped with a convex surface to the second object, a second positive lens which is disposed as adjacent to the lens of the biconcave shape on the second object side and shaped with a convex surface to the first object side, and at least three further positive lenses. <IMAGE> |
