Patent ID: 6989946
Filing Date: 2006-01-24
Classification: G02B

Abstract:
1. A projection lens which projects an image of an image display device on a surface of a screen, the projection lens, wherein a first group having a negative refractive power and a second group having a positive refractive power are arranged in order from a magnified side toward a reduced side, the first group is configured to arrange a first lens and a second lens in order from the magnified side, and the second group is configured to arrange a third lens to a seventh lens in order from the magnified side, the first lens is a negative meniscus lens whose both surfaces are formed by aspherical surface in which an area near an optical axis of the surface on the magnified side is a concave surface, the second lens is the negative meniscus lens whose both surfaces are formed by the aspherical surface in which the area near the optical axis of the surface on the magnified side is the concave surface, the third lens is a cemented lens in which a bi-concave lens is cemented to the surface on the reduced side of a bi-convex lens, the fourth lens is a positive meniscus lens whose both surfaces are formed by the aspherical surface, and a convex surface of the positive meniscus lens faces toward the reduced side, the fifth lens is the cemented lens in which the bi-concave lens is cemented to the surface on the reduced side of the bi-convex lens, the sixth lens is a positive lens whose strong convex surface faces toward the reduced side, the seventh lens is the positive lens whose both surfaces are a convex surface, and a stop is arranged between the first group and the second group.