| 摘要 |
An ultraviolet imaging system includes at least two negative lens elements, and at least two positive lens elements. The ultraviolet imaging system satisfies the following conditions: -3<f(i=330)/r1<-0.5 (1) 65<nu (ALL) (2) 0<NU(i=330) (P)-nu(i=330) (N)<10 (3) wherein f(i=330) designates the focal length of the entire ultraviolet imaging system with respect to a wavelength "i" of 330 nm (base wavelength); r1 designates the radius of curvature of the object-side surface of the most object-side lens element; nu (ALL) designates a reciprocal of a dispersion value, with respect to the d-line, of the glass material of all of the lens elements; nu(i=330) (P) designates the reciprocal of the dispersion value, for the positive lens elements, with respect to the wavelength of 330 nm; and nu(i=330) (N) designates the reciprocal of the dispersion value, for the negative lens elements, with respect to the wavelength of 330 nm.
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