CN-121721823-B - Large-aperture long-wave athermalized infrared lens

CN121721823BCN 121721823 BCN121721823 BCN 121721823BCN-121721823-B

Abstract

The invention relates to the technical field of optical lenses, and particularly discloses a large aperture long wave athermalization infrared lens which comprises a first lens, a second lens, a third lens and a fourth lens, wherein the first lens, the second lens, the third lens and the fourth lens are sequentially arranged on the same optical axis along the light incidence direction, the first lens is a positive focal power meniscus lens, the second lens is a negative focal power meniscus lens, the third lens is a positive focal power meniscus lens, the fourth lens is a positive focal power meniscus lens, and the first lens, the second lens, the third lens and the fourth lens are all aspheric lenses.

Inventors

ZENG QINYONG
YIN XIAOJIE
CAI YUANHONG

Assignees

成都浩孚科技有限公司

Dates

Publication Date: 20260508
Application Date: 20260226

Claims (4)

1. The large aperture long wave athermalized infrared lens is characterized in that the lens has optical refractive power and comprises four parts, namely a first lens, a second lens, a third lens and a fourth lens, wherein the first lens, the second lens, the third lens and the fourth lens are sequentially arranged on the same optical axis along the incidence direction of light rays, the first lens is a positive focal power meniscus lens, the second lens is a negative focal power meniscus lens, the third lens is a positive focal power meniscus lens, the fourth lens is a positive focal power meniscus lens, and the first lens, the second lens, the third lens and the fourth lens are all aspheric lenses; the lens satisfies the following conditions along the optical axis direction: , wherein, The interval distance between the light emergent surface of the first lens and the light incident surface of the second lens on the optical axis is the same, Is the total focal length of the lens; The light incident surfaces of the first lens, the second lens, the third lens and the fourth lens are all convex surfaces, and the light emergent surfaces of the first lens, the second lens, the third lens and the fourth lens are all concave surfaces; The focal lengths of the first lens, the second lens, the third lens and the fourth lens and the total focal length of the lens meet the following conditions: , , , , Wherein, the 、、、 The focal lengths of the first lens, the second lens, the third lens and the fourth lens are respectively; The total optical length of the lens and the total focal length of the lens satisfy the following conditions: , Wherein, the Is the optical total length of the lens; the back focal length of the lens and the total focal length of the lens satisfy the following conditions: , Wherein, the A back focal length of the lens; Maximum clear aperture number of the lens 0.78, Total focal length of the lens Is 70mm, and the lens is adapted to an infrared detector with a pixel size of 10um or 12 um.
2. The large aperture long wave athermalized infrared lens according to claim 1, wherein a diaphragm of said lens is disposed on a light incident surface of said first lens.
3. The large aperture long wave athermalized infrared lens according to claim 1, wherein said first lens, said third lens and said fourth lens are all made of chalcogenide glass, and said second lens is made of zinc selenide.
4. The large aperture long wave athermalized infrared lens according to claim 1, wherein the light incident surface of the first lens, the light incident surface of the second lens, the light incident surface of the third lens and the light incident surface of the fourth lens are all even aspheric surfaces.

Description

Large-aperture long-wave athermalized infrared lens Technical Field The invention relates to the technical field of optical lenses, and particularly discloses a large-aperture long-wave athermalized infrared lens. Background With the rapid development of uncooled infrared detector technology, the low-pixel and high-resolution cooled and uncooled detectors have gradually become a mainstream trend in the industry, and long-wave infrared lenses are widely applied to key fields such as forest fire prevention, gas detection, unmanned aerial vehicle pods and the like, however, the long-wave infrared lenses in the prior art still have a plurality of defects in design and manufacture. On one hand, in order to pursue larger light flux, the traditional large-aperture lens is huge and heavy, the structure is not compact enough, the severe requirements of loads such as unmanned aerial vehicle and the like on light weight are difficult to meet, in order to correct chromatic aberration and realize athermalization, expensive infrared lens materials are often used in a large amount in the existing design, so that the manufacturing cost is high, on the other hand, part of the lens adopts a binary diffraction surface design, although the number of lenses is reduced, the diffraction efficiency of the binary surface is low, the stray light risk is high, the lens is extremely sensitive to processing precision and assembly tolerance, and the imaging quality is reduced. In addition, the conventional long-wave infrared lens on the market is generally smaller in aperture, the F number is generally larger than or equal to 1.0, and the signal to noise ratio is reduced due to insufficient light quantity under severe environments such as smoke, rain and snow, and the imaging quality is difficult to guarantee. More importantly, due to the limitation of physical optical diffraction effect, the diffraction limit of the long-wave infrared lens with the F number of 1.0 is about 12um, which means that when the pixel size of the detector is reduced to 12um or even 10um, the theoretical resolution of the lens is close to the physical limit, the high resolution performance of a new generation of small pixel detector cannot be fully exerted, the imaging detail of the whole system is lost, and the increasingly high-definition imaging requirement of a user cannot be met. In view of the above, the prior art cannot satisfy the requirements of large aperture, high resolution, miniaturization and low cost, so it is highly desirable to provide a large aperture long wave athermalized infrared lens. Disclosure of Invention The present invention is directed to a large aperture long wave athermalized infrared lens, which at least solves one of the above problems in the prior art. Specifically, the invention is realized by the following technical scheme: The large aperture long wave athermalization infrared lens comprises a first lens, a second lens, a third lens and a fourth lens, wherein the first lens, the second lens, the third lens and the fourth lens are sequentially arranged on the same optical axis along the incidence direction of light, the first lens is a positive focal power meniscus lens, the second lens is a negative focal power meniscus lens, the third lens is a positive focal power meniscus lens, the fourth lens is a positive focal power meniscus lens, and the first lens, the second lens, the third lens and the fourth lens are all aspheric lenses; the lens satisfies the following conditions along the optical axis direction: , wherein, The interval distance between the light emergent surface of the first lens and the light incident surface of the second lens on the optical axis is the same,Is the total focal length of the lens. Further, the diaphragm of the lens is arranged on the light incident surface of the first lens. Furthermore, the light incident surfaces of the first lens, the second lens, the third lens and the fourth lens are convex, and the light emergent surfaces thereof are concave. Further, the focal lengths of the first lens, the second lens, the third lens and the fourth lens and the total focal length of the lens satisfy the following conditions: , , , , Wherein, the 、、、The focal lengths of the first lens, the second lens, the third lens and the fourth lens are respectively. Further, the first lens, the third lens and the fourth lens are all made of chalcogenide glass, and the second lens is made of zinc selenide. Further, the light incident surface of the first lens, the light incident surface of the second lens, the light incident surface of the third lens and the light incident surface of the fourth lens are all even-order aspheric surfaces. Further, the total optical length of the lens and the total focal length of the lens satisfy: , Wherein, the Is the optical total length of the lens. Further, the back focal length of the lens and the total focal length of the lens satisfy: , Wherein, the Is the back focal length of