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US 2019/0094495 A1Published application
Imaging lens and optical apparatus
AssigneeFUJIFILM Corporation
InventorsMasaru AMANO, Masao MORI, Taro ASAMI, Kazuyoshi OKADA
Life of this patent
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Abstract
The imaging lens includes at least one positive lens that satisfies predetermined conditional expressions (1) to (3) indicating conditions in which dispersion is relatively low and refractive index is high while having a negative rate of change of the refractive index. In a case where a lens that satisfies a conditional expression (4) meaning a low dispersion material is included, the lens that satisfies the conditional expression (4) satisfies a predetermined conditional expression (5).
Claims16
An imaging lens in which a plurality of lenses are combined with each other, comprising:
- at least one positive lens that satisfies the following Conditional Expressions (1) to (3) in a case where a refractive index at a d line of a positive lens included in the imaging lens is set to nP, an Abbe number at the d line of the positive lens is set to νP, and a rate of change of the refractive index at the d line of the positive lens with respect to a change in temperature at 25° C. is set to dnP/dt,
- 1.65<nP<1.75 (1)
- 45<νP<55 (2)
- dnP/dt<0×10−6/° C. (3)
- wherein in a case where a lens that satisfies the following Conditional Expression (4) is included, the lens that satisfies the following Conditional Expression (4) satisfies the following Conditional Expression (5) in a case where an Abbe number at the d line of a lens included in the imaging lens is set to νd, and a partial dispersion ratio of the lens included in the imaging lens is set to θgF.
- 60<νd (4)
- 0.6<θgF+0.001618×νd<0.644 (5)
4 more elements
Dependencies are inferred from the claim text.