| 摘要 |
A projection lens system for use in a rear type projection television. The system includes a first lens of which at least one surface is aspherical, the center portion of which has little optical power, and the peripheral portion of which has a weak positive optical power. A second lens of the system has a strong positive optical power and a bi-convex shape, wherein at least one of its surfaces is aspherical. A third lens in the system has a strong negative optical power and a bi-concave shape, and has at least one surface that is aspherical. A fourth lens has a strong positive optical power and a bi-convex shape, and at least one aspherical surface. A fifth lens has a weak negative optical power and a meniscus shape, wherein at least one surface is aspherical. The projection lens system reduces the number of lenses required, as compared with the prior art, provides a brighter picture and a greater field angle, and facilitates the correction of chromatic aberrations.
|
