| 摘要 |
The invention is directed to a stereoscopic microscope objective. A microscope objective of this kind contains five lenses. The first lens, considered from the object side, has a focal length between -2.11f and -1.20f; f is the total focal length of the microscope objective. This is followed by a second lens with a focal length between 1.30f and 1.45f, a third lens with a focal length between 1.15f and 1.37f, a fourth lens with a focal length between 0.65f and 1.7f, and a fifth lens with a focal length between -0.96f and 0.48f. Combined, the amount of the refractive power of the last two lenses is less than 0.31f. In the first lens and fifth lens, at least 80% of the refractive power is concentrated on the image-side surfaces. In the second lens, at least 60% of the refractive power is concentrated on the image-side surface. In the third lens, at least 60% of the refractive power is concentrated on the object-side surface. In the fourth lens, at least 70% of the refractive power is concentrated on the image-side surface. The first lens and the fifth lens are made of a material having an anomalous partial dispersion of a first type. The second lens, third lens and fourth lens are made of a material having an anomalous partial dispersion of a second type.
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