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US 10,852,535 B2Granted
Imaging lens and optical apparatus
AssigneeFUJIFILM Corporation
InventorsYukiko Nagatoshi, Shunsuke Miyagishima, Kazuyoshi Okada, Ukyo Tomioka, Masaru Yonezawa, Yasutaka Shimada
Life of this patent
Estimating the term…
Abstract
The imaging lens includes at least one negative 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. A positive lens having a largest Abbe number at the d line among positive lenses included in the imaging lens satisfies predetermined Conditional Expressions (4) and (5).
Claims16
An imaging lens in which a plurality of lenses are combined with each other, comprising:
- at least one negative lens that satisfies the following Conditional Expressions (1) to (3) in a case where a refractive index at a d line of a negative lens included in the imaging lens is set to nN, an Abbe number at the d line of the negative lens is set to νN, and a rate of change of the refractive index at the d line of the negative lens with respect to a change in temperature at 25° C. is set to dnN/dt,
- 1.65<nN<1.75 (1)
- 45<νN<55 (2)
- dnN/dt<0×10−6/° C. (3)
- wherein a positive lens having a largest Abbe number at the d line among positive lenses included in the imaging lens satisfies the following Conditional Expressions (4) and (5) in a case where an Abbe number at the d line of the positive lens having a largest Abbe number at the d line is set to νP1, and a partial dispersion ratio of the positive lens having a largest Abbe number at the d line is set to θP1gF,
- 63<νP1 (4)
- 0.644<θP1gF+0.001618×νP1 (5).
4 more elements
Dependencies are inferred from the claim text.