| 摘要 |
PROBLEM TO BE SOLVED: To provide a projection lens which reduces the thickness of a projection television, facilitates the arrangement of optical parts for color separation and synthesis and reduces longitudinal chromatic aberration. SOLUTION: A first lens group having a negative power, a second lens group having a positive power are arranged from the screen side of a projection display device, and an aperture diaphragm is positioned between the first lens group and the second lens group. The first lens group includes at least one aspherical lens element and at least three spherical lens elements, and the lens element of the first lens group spaced away from the screen by a maximum distance has a positive power, and the second lens group includes a triple cemented lens composed of three lens elements cemented together, and further includes at least one lens element having positive power and arranged at one side of the triple cemented lens opposite to the screen.
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