| 摘要 |
An achromatic microscope objective having three lens components. The first and second components are individual positive lens elements and the third component is a cemented doublet made up of a negative element and a biconvex positive element. The objective is characterized by a particularly advantageous selection of the glasses used for the respective elements. The first or front element has an index of refraction in the range of 1.55 to 1.70 and an Abbe number in the range of 45 to 68; the second element has these same ranges; the third element (negative element of the doublet) has an index of refraction in the range of 1.65 to 1.97 and an Abbe number in the range of 20 to 40; and the fourth element (positive element of the doublet) has an index of refraction in the range of 1.46 to 1.57 and an Abbe number in the range of 50 to 85. By using glasses having these characteristics, it is possible to produce at modest expense a microscope objective with very good correction of all image errors.
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