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DE-102015114518-B4 - Imaging lens and imaging device

DE102015114518B4DE 102015114518 B4DE102015114518 B4DE 102015114518B4DE-102015114518-B4

Abstract

Imaging lens consisting, in order starting from the object side, of a first lens (L1) with a negative refractive power, a second lens (L2) with a positive refractive power, a third lens (L3) with a positive refractive power, a fourth lens (L4) with a negative refractive power, a fifth lens (L5) with a positive refractive power, a sixth lens (L6) with a positive refractive power and a seventh lens (L7) with a negative refractive power, wherein the following condition formulas are satisfied: f 12 / f < − 3,2 vd 7 < 55 40 < vd 3 where, f12 is the combined focal length of the first lens (L1) and the second lens (L2), f is the focal length of the entire system, vd7 is the Abbe number of the material of the seventh lens (L7) with respect to the d-line, and vd3 is the Abbe number of the material of the third lens (L3) with respect to the d-line.

Inventors

  • Taro Asami

Assignees

  • Jiangxi Ofilm Optical Co., Ltd.

Dates

Publication Date
20260513
Application Date
20150831
Priority Date
20140919

Claims (16)

  1. Imaging lens consisting, in order starting from the object side, of a first lens (L1) with a negative refractive power, a second lens (L2) with a positive refractive power, a third lens (L3) with a positive refractive power, a fourth lens (L4) with a negative refractive power, a fifth lens (L5) with a positive refractive power, a sixth lens (L6) with a positive refractive power and a seventh lens (L7) with a negative refractive power, wherein the following condition formulas are satisfied: f 12 / f < − 3,2 vd 7 < 55 40 < vd 3 where f12 is the combined focal length of the first lens (L1) and the second lens (L2), f is the focal length of the entire system, vd7 is the Abbe number of the material of the seventh lens (L7) with respect to the d-line, and vd3 is the Abbe number of the material of the third lens (L3) with respect to the d-line.
  2. Imaging lens consisting, in order starting from the object side, of a first lens (L1) with a negative refractive power, a second lens (L2) with a positive refractive power, a third lens (L3) with a positive refractive power, a fourth lens (L4) with a negative refractive power, a fifth lens (L5) with a positive refractive power, a sixth lens (L6) with a positive refractive power and a seventh lens (L7) with a negative refractive power, wherein the following condition formulas are satisfied: f 12 / f < − 3,2 D 4 / f < 0,39 where f12 is the combined focal length of the first lens (L1) and the second lens (L2), f is the focal length of the entire system, and D4 is the air gap between the second lens (L2) and the third lens (L3).
  3. imaging lens according to Claim 2 , where the following condition formula is still fulfilled: 40 < vd 3 where vd3 is the Abbe number of the material of the third lens (L3) with respect to the d-line.
  4. Imaging lens according to one of the Claims 1 until 3 , where the following condition formula is still fulfilled: 25 < vd 5 where vd5 is the Abbe number of the material of the fifth lens (L5) with respect to the d-line.
  5. Imaging lens according to one of the Claims 1 until 4 , where the following condition formula is still fulfilled: 0,5 < f 3 / f < 10 where f3 is the focal length of the third lens (L3), and f is the focal length of the entire system.
  6. Imaging lens according to one of the Claims 1 until 5 , where the following condition formula is still fulfilled: 0,5 < f 2 / f < 7 where f2 is the focal length of the second lens (L2), and f is the focal length of the entire system.
  7. Imaging lens according to one of the Claims 1 until 6 , where the following conditional formula is satisfied: f 1 / f < − 0,25 where f1 is the focal length of the first lens (L1), and f is the focal length of the entire system.
  8. Imaging lens according to one of the Claims 1 until 7 , where the following conditional formula is satisfied: 0,3 < f 123 / f < 15 where f123 is the combined focal length of the first lens (L1), the second lens (L2) and the third lens (L3), and f is the focal length of the entire system.
  9. Imaging lens according to one of the Claims 1 until 8 , where the following condition formula is still fulfilled: 0,5 < f 234 / f < 18 where f234 is the combined focal length of the second lens (L2), the third lens (L3) and the fourth lens (L4), and f is the focal length of the entire system.
  10. Imaging lens according to one of the Claims 1 until 9 , where the following condition formula is still fulfilled: 0,5 < f 12345 / f < 10 where f12345 is the combined focal length of the first lens (L1), the second lens (L2), the third lens (L3), the fourth lens (L4) and the fifth lens (L5), and f is the focal length of the entire system.
  11. Imaging lens according to one of the Claims 1 until 10 , where the following condition formula is still fulfilled: − 5,0 < ( R 14 + R 15 ) / ( R 14 − R 15 ) < − 0,01 where R14 is the radius of curvature of the object-side surface of the seventh lens (L7), and R15 is the radius of curvature of the image-side surface of the seventh lens (L7).
  12. Imaging lens according to one of the Claims 1 until 11 , where the following condition formula is still fulfilled: 0,4 < f 2345 / f < 10 where f2345 is the combined focal length of the second lens (L2), the third lens (L3), the fourth lens (L4) and the fifth lens (L5), and f is the focal length of the entire system.
  13. Imaging lens according to one of the Claims 1 until 12 , where the following condition formula is still fulfilled: 0,1 < f 3456 / f < 5,0 where f3456 is the combined focal length of the third lens (L3), the fourth lens (L4), the fifth lens (L5) and the sixth lens (L6), and f is the focal length of the entire system.
  14. Imaging lens according to one of the Claims 1 until 13 , where the following condition formula is still fulfilled: − 4,0 < ( R 8 + R 9 ) / ( R 8 − R 9 ) < 4,0 where R8 is the radius of curvature of the object-side surface of the fourth lens (L4), and R9 is the radius of curvature of the image-side surface of the fourth lens (L4).
  15. Imaging lens according to one of the Claims 1 until 14 , where the following condition formula is still fulfilled: − 3 < f / f 45 < 3 where f45 is the combined focal length of the fourth lens (L4) and the fifth lens (L5), and f is the focal length of the entire system.
  16. Imaging device equipped with the imaging lens according to one of the Claims 1 until 15 .

Description

BACKGROUND OF THE INVENTION Field of invention The present invention relates to an imaging lens and an imaging device, and in particular an imaging lens suitable for use in a vehicle-based camera for taking pictures, especially in front of, to the side, behind, etc. of vehicles, in a camera of a portable terminal device and in a surveillance camera which uses image sensors such as CCDs (Charge Coupled Device), CMOSs (Complementary Metal Oxide Semiconductor) and the like, and an imaging device which is equipped with this imaging lens. Description of the state of the art In recent years, miniaturization and an increased number of pixels have been achieved in image sensors such as CCDs, CMOS, and the like. Alongside these developments, and because the size of the bodies of imaging devices equipped with these image sensors has also been miniaturized, the imaging lenses attached to them must also be miniaturized and lighter, in addition to offering favorable optical performance. Meanwhile, lenses used in vehicle-based cameras, handheld cameras, surveillance cameras, and similar devices are required to exhibit high weather resistance, usability across a wide temperature range from ambient temperatures in cold climates to the temperatures inside a vehicle in the tropics during summer, compactness, and high performance. In particular, cameras positioned inside vehicles to monitor their front require low f-numbers and usability across a wide wavelength range, from the visible to the infrared, to enable nighttime use. Furthermore, when lenses are used in vehicle-based cameras, the exterior image of the vehicle also requires that lens sections exposed to the outside of the vehicle be small. The Japanese patent publication JP 2010-91697 A proposes an imaging lens with a six-lens configuration, in which a negative lens, a positive lens, a positive lens, a negative lens, a positive lens and a positive lens are arranged in order starting from the object side, as imaging lenses to be attached to vehicle-based cameras. Furthermore, the US 8,797,659 B2 A focusing macro lens with three different lens groups, in which focusing is achieved by fixing the first lens group and the second lens group and by moving the second lens group with a positive refractive power as a whole on the optical axis when focusing from an infinity object to an object at a short distance. SUMMARY OF THE INVENTION The requirements for imaging lenses for mounting on vehicle-based cameras, surveillance cameras, and the like are becoming stricter every year, and it is therefore important for the JP 2010-91697 A The revealed imaging lens would be desirable to have a smaller F-number and achieve higher performance. The present invention was developed in light of the aforementioned circumstances. The object of the present invention is to provide an imaging lens with a small f-number that is capable of achieving high performance, as well as an imaging device equipped with this imaging lens. This problem is solved with an imaging lens having the features of claim 1 and with an imaging lens having the features of claim 2. A first imaging lens of the present invention consists, in order starting from the object side, essentially of a first lens with a negative refractive power, a second lens with a positive refractive power, a third lens with a positive refractive power, a fourth lens with a negative refractive power, a fifth lens with a positive refractive power, a sixth lens with a positive refractive power and a seventh lens with a negative refractive power, wherein The following conditional formulas must be fulfilled: f12/f<−3,2νd7<5540<νd3 where, f12 is the combined focal length of the first lens and the second lens, f is the focal length of the entire system, vd7 is the Abbe number of the material of the seventh lens with respect to the d-line, and vd3 is the Abbe number of the material of the third lens with respect to the d-line. A second imaging lens of the present invention consists, in order starting from the object side, essentially of a first lens with a negative refractive power, a second lens with a positive refractive power, a third lens with a positive refractive power, a fourth lens with a negative refractive power, a fifth lens with a positive refractive power, a sixth lens with a positive refractive power and a seventh lens with a negative refractive power, wherein The following conditional formulas must be fulfilled: f12/f<−3,2D4/f<0,39 where, f12 is the combined focal length of the first lens and the second lens, f is the focal length of the entire system, and D4 is the air gap between the second lens and the third lens. It should be noted that the above expression “consists essentially of” means that, in addition to the lenses listed as constituent elements, the imaging lens according to the invention may also include lenses that have practically no refractive power, optical elements other than lenses such as an aperture and a cover glass,