Imaging lens and optical apparatus

Patent metadata

Field	Value
Publication number	US-10310239-B2
Application number	US-201715830465-A
Country	US
Kind code	B2
Filing date	Dec 4, 2017
Priority date	Dec 7, 2016
Publication date	Jun 4, 2019
Grant date	Jun 4, 2019

Abstract

The imaging lens consists of, in order from a magnified side, a first lens having a positive refractive power, a second lens having a positive refractive power, a third lens having a negative refractive power, a fourth lens having a negative refractive power, a fifth lens having a positive refractive power, a sixth lens having a positive refractive power, and a seventh lens having a positive refractive power, and satisfies predetermined Conditional Expressions (1) and (2) relating to Abbe numbers of the second lens to the fifth lens.

First claim

What is claimed is:

1. An imaging lens consisting of, in order from a magnified side:
a first lens having a positive refractive power;
a second lens having a positive refractive power;
a third lens having a negative refractive power;
a fourth lens having a negative refractive power;
a fifth lens having a positive refractive power;
a sixth lens having a positive refractive power; and
a seventh lens having a positive refractive power,
wherein the following Conditional Expressions (1) and (2) are satisfied,
−50<ν d 2−ν d 3<−15  (1)

−80<ν d 4−ν d 5<−40  (2)

where νd2 is an Abbe number of the second lens in a d line,
νd3 is an Abbe number of the third lens in the d line,
νd4 is an Abbe number of the fourth lens in the d line,
νd5 is an Abbe number of the fifth lens in the d line, and
wherein the following Conditional Expression (3) is satisfied,
5<| f 45/ f 23|<30  (3),

where f45 is a composite focal length of the fourth lens and the fifth lens in the d line, and
f23 is a composite focal length of the second lens and the third lens in the d line.

2. The imaging lens according to claim 1 ,
wherein the following Conditional Expression (4) is satisfied,
6<| f 45/ f|< 40  (4)

where f45 is a composite focal length of the fourth lens and the fifth lens in the d line, and
f is a focal length of the whole system in the d line.

3. The imaging lens according to claim 1 ,
wherein the following Conditional Expression (5) is satisfied,
2< f 1 /f< 15  (5)

where f1 is a focal length of the first lens in the d line, and
f is a focal length of the whole system in the d line.

4. The imaging lens according to claim 1 ,
wherein the following Conditional Expression (6) is satisfied,
0.5<|( R 2+ R 1)/( R 2− R 1)|<1.2  (6)

where R2 is a curvature radius of a surface of the first lens on a reduced side, and
R1 is a curvature radius of a surface of the first lens on the magnified side.

5. The imaging lens according to claim 1 ,
wherein a surface of the sixth lens on the magnified side and a surface of the seventh lens on the magnified side have convex surfaces thereof directed toward the magnified side.

6. The imaging lens according to claim 1 ,
wherein the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens and the seventh lens are all single lenses.

7. The imaging lens according to claim 1 ,
wherein the following Conditional Expression (1-1) is satisfied,
−50<ν d 2−ν d 3<−20  (1-1).

8. The imaging lens according to claim 1 ,
wherein the following Conditional Expression (1-2) is satisfied,
−40<ν d 2−ν d 3<−22  (1-2).

9. The imaging lens according to claim 1 ,
wherein the following Conditional Expression (2-1) is satisfied,
−70<ν d 4−ν d 5<−42  (2-1).

10. The imaging lens according to claim 2 ,
wherein the following Conditional Expression (4-1) is satisfied,
7<| f 45/ f|< 30  (4-1).

11. The imaging lens according to claim 3 ,
wherein the following Conditional Expression (5-1) is satisfied,
2.5< f 1 /f< 10  (5-1).

12. The imaging lens according to claim 4 ,
wherein the following Conditional Expression (6-1) is satisfied,
0.6<|( R 2+ R 1)/( R 2− R 1)|<1.2  (6-1).

13. An optical apparatus comprising the imaging lens according to claim 1 .

Assignees

• Fujifilm Corp

Inventors

• Harada Keisuke

Classifications

• G02B15/04

  by changing a part · CPC title

• G02B27/0101

  characterised by optical features (G02B27/0172 takes precedence) · CPC title

• G02B13/0045

  having five or more lenses · CPC title

• G02B13/16 Primary

  for use in conjunction with image converters or intensifiers {, or for use with projectors, e.g. objectives for projection TV} · CPC title

• G02B9/64

  having more than six components · CPC title