CN219105264U - Long-wave infrared zoom lens - Google Patents

Abstract

The utility model discloses a long-wave infrared zoom lens, which comprises a front fixed group, a zoom group, a compensation group and a rear fixed group which are sequentially arranged along an optical axis from an object plane to an image plane, wherein the front fixed group is a positive lens group and comprises a first lens, and the first lens is a meniscus lens; the zoom group is a negative lens group and comprises a second lens, and the second lens is a biconcave lens; the compensation group is a positive lens group and comprises a third lens, the third lens is a biconvex lens, the rear fixed group is a positive lens group and comprises a fourth lens, a fifth lens and a sixth lens, and a diaphragm is arranged between the third lens and the fourth lens; the spacing distance between the adjacent surfaces of the fourth lens and the fifth lens is 11-14mm; according to the utility model, the design of the long-wave infrared zoom lens with the focal length of 24-130 mm is realized under the matching requirement of the uncooled detector, the structure is simple and compact, the athermalization design is satisfied, the installation is easy, and the standardized mass production is easy to realize.

Description

Long-wave infrared zoom lens

Technical Field

The utility model relates to a zoom lens, in particular to a long-wave infrared zoom lens.

Background

The infrared detection technology has the advantages of good anti-interference performance, longer night acting distance, strong smoke and haze penetrating capability, day and night working capability and strong capability of being suitable for various weather.

The uncooled long-wave infrared zoom lens is matched with an infrared uncooled detector for use in a night monitoring system without an auxiliary light source, can be used for searching a large-view-field target and tracking a small-view-field target according to the optical characteristics of the uncooled long-wave infrared zoom lens, is widely applied to the fields of security guard, investigation and the like from army to civilian use, and has very wide application prospect and increasingly-increased requirements.

The uncooled detector has the advantages of light weight, small volume, low cost and the like, and has wide application in the infrared detection field. In recent years, the technology for producing the uncooled detector has been greatly developed, and simultaneously, higher requirements are also put forward on the uncooled infrared lens matched with the uncooled detector.

The long-wave infrared zoom lens can simultaneously meet the requirement of finding a target in short focus and identifying the target in long focus, and the target is not lost in the zooming process.

The design of the long-wave zooming infrared lens with large zoom ratio is difficult by one level, most of the designs of the existing long-wave infrared zooming lenses are not optimized, and the design needs to be further improved.

Disclosure of Invention

The present utility model is directed to a long-wave infrared zoom lens, which solves the problems set forth in the above-mentioned background art.

In order to achieve the above purpose, the present utility model provides the following technical solutions:

the long-wave infrared zoom lens comprises a front fixed group, a zoom group, a compensation group and a rear fixed group which are sequentially arranged from an object plane to an image plane along an optical axis, wherein the front fixed group is a positive lens group and comprises a first lens, and the first lens is a meniscus lens; the zoom group is a negative lens group and comprises a second lens, and the second lens is a biconcave lens; the compensation group is a positive lens group and comprises a third lens, the third lens is a biconvex lens, the rear fixed group is a positive lens group and comprises a fourth lens, a fifth lens and a sixth lens, and a diaphragm is arranged between the third lens and the fourth lens.

As a further scheme of the utility model: the distance between the adjacent surfaces of the fourth lens and the fifth lens is 11-14mm.

As a further scheme of the utility model: the distance between the adjacent surfaces of the fifth lens and the sixth lens is 34-37mm.

As a further scheme of the utility model: the first lens, the second lens, the third lens, the fifth lens and the sixth lens are made of germanium, and the fourth lens is made of zinc selenide.

As still further aspects of the utility model: the first lens is a meniscus lens with positive focal power, and the convex surface faces to the object space;

the second lens is a biconcave lens with negative focal power, and one surface facing the image surface adopts an aspheric surface;

the third lens is a biconvex lens with positive focal power, and one surface facing the object plane adopts an aspheric surface;

the fourth lens is a meniscus lens with negative focal power, and the convex surface faces the object plane;

the fifth lens is a meniscus lens with positive focal power, and the convex surface faces the image surface;

the sixth lens is a biconvex lens with positive focal power, and one surface facing the object plane adopts an aspheric surface.

Compared with the prior art, the utility model has the beneficial effects that:

according to the utility model, the design of the long-wave infrared zoom lens with the focal length of 24-130 mm is realized under the matching requirement of the uncooled detector, the structure is simple and compact, the weight is light, the athermalization design is satisfied, and the standard batch production is easy to install and realize.

Drawings

Fig. 1 is a schematic structural diagram of a long-wave infrared zoom lens.

Wherein, the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5 and the sixth lens 6.

Detailed Description

In order to make the technical problems, technical schemes and beneficial effects to be solved more clear, the utility model will be further described in detail with reference to the following examples. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the utility model.

It will be understood that when an element is referred to as being "mounted" or "disposed" on another element, it can be directly on the other element or be indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or be indirectly connected to the other element.

It is to be understood that the terms "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and the like indicate or are based on the orientation or positional relationship shown in the drawings, merely to facilitate describing the present utility model and simplify the description, and do not indicate or imply that the devices or elements referred to must have the orientation specific to the specification, be constructed and operated in the specific orientation, and thus should not be construed as limiting the present utility model.

Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include one or more such feature.

Referring to fig. 1, in an embodiment of the present utility model, a long-wave infrared zoom lens includes a front fixed group, a zoom group, a compensation group, and a rear fixed group sequentially disposed along an optical axis from an object plane to an image plane, where the front fixed group is a positive lens group and includes a first lens 1, and the first lens 1 is a meniscus lens; the variable magnification group is a negative lens group and comprises a second lens 2, and the second lens 2 is a biconcave lens; the compensation group is a positive lens group and comprises a third lens 3, the third lens 3 is a biconvex lens, the rear fixed group is a positive lens group and comprises a fourth lens 4, a fifth lens 5 and a sixth lens 6, and a diaphragm is arranged between the third lens 3 and the fourth lens 4.

The distance between the adjacent surfaces of the fourth lens 4 and the fifth lens 5 is 12.44mm.

The distance between the adjacent surfaces of the fifth lens 5 and the sixth lens 6 is 35.58mm.

The materials of the first lens 1, the second lens 2, the third lens 3, the fifth lens 5 and the sixth lens 6 are germanium, and the material of the fourth lens 4 is zinc selenide.

The first lens 1 is a meniscus lens with positive focal power, and the convex surface faces to the object space;

the second lens 2 is a biconcave lens with negative focal power, and one surface facing the image surface adopts an aspheric surface;

the third lens 3 is a biconvex lens with positive focal power, and one surface facing the object plane adopts an aspheric surface;

the fourth lens 4 is a meniscus lens with negative focal power, and the convex surface faces the object plane;

the fifth lens 5 is a meniscus lens with positive focal power, and the convex surface faces the image surface;

the sixth lens 6 is a biconvex lens with positive focal power, and one surface facing the object plane adopts an aspheric surface.

Specifically, the specification parameters of each lens in the present utility model are shown in table 1:

table 1 wherein the aspherical surface satisfies the following formula:

wherein, when Z is the position of the aspheric surface with the height R along the optical axis direction, the distance from the vertex of the aspheric surface is not high, c=1/R, and R represents the paraxial curvature radius of the mirror surface; k is a cone coefficient; a, B, C, D are higher order aspheric coefficients.

In the present utility model, the distance between the zoom group and the compensation group is matched to realize the zooming process, please refer to table 2

TABLE 2

The imaging quality realized by the lens in the utility model is as follows:

a)MTF：

24mm focal length, at a spatial frequency of 30lp/mm, a center 0.7 field of view MTF greater than 0.52, and an edge field of view greater than 0.42;

130mm focal length, at a spatial frequency of 30lp/mm, a center 0.7 field of view MTF greater than 0.52, and an edge field of view greater than 0.42;

b) Dispersion characteristics: the optical imaging dispersion characteristics are shown in tables 3 and 4:

table 3: dispersion characteristics of focal length 24mm

Table 4: dispersion characteristics of 130mm focal length

c) Distortion characteristics: the imaging maximum distortion of the focal length 130mm is not more than 1.8%, and the imaging maximum distortion of the focal length 24mm is not more than 3.2%;

the utility model adopts the same germanium, zinc selenide and germanium material, and has high-quality imaging image quality in the range of the ambient temperature of minus 40 ℃ to plus 60 ℃ through optical design optimization.

Although the present utility model has been described with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications may be made to the embodiments described, or equivalents may be substituted for elements thereof, and any modifications, equivalents, improvements and changes may be made without departing from the spirit and principles of the present utility model.

Claims (5)

1. The utility model provides a long wave infrared zoom lens which characterized in that: the lens comprises a front fixed group, a zoom group, a compensation group and a rear fixed group which are sequentially arranged from an object plane to an image plane along an optical axis, wherein the front fixed group is a positive lens group and comprises a first lens (1), and the first lens (1) is a meniscus lens; the variable magnification group is a negative lens group and comprises a second lens (2), and the second lens (2) is a biconcave lens; the compensation group is a positive lens group and comprises a third lens (3), the third lens (3) is a biconvex lens, the rear fixed group is a positive lens group and comprises a fourth lens (4), a fifth lens (5) and a sixth lens (6), and a diaphragm is arranged between the third lens (3) and the fourth lens (4).

2. The long-wave infrared zoom lens according to claim 1, wherein: the distance between the adjacent surfaces of the fourth lens (4) and the fifth lens (5) is 11-14mm.

3. The long-wave infrared zoom lens according to claim 1, wherein: the distance between the adjacent surfaces of the fifth lens (5) and the sixth lens (6) is 34-37mm.

4. The long-wave infrared zoom lens according to claim 1, wherein: the first lens (1), the second lens (2), the third lens (3), the fifth lens (5) and the sixth lens (6) are made of germanium, and the fourth lens (4) is made of zinc selenide.

5. The long-wave infrared zoom lens according to claim 1, wherein: the first lens (1) is a meniscus lens with positive focal power, and the convex surface faces to the object space;

the second lens (2) is a biconcave mirror with negative focal power, and one surface facing the image surface adopts an aspheric surface;

the third lens (3) is a biconvex lens with positive focal power, and one surface facing the object plane adopts an aspheric surface;

the fourth lens (4) is a meniscus lens with negative focal power, and the convex surface faces the object plane;

the fifth lens (5) is a meniscus lens with positive focal power, and the convex surface faces the image surface;

the sixth lens (6) is a biconvex lens with positive focal power, and one surface facing the object plane adopts an aspheric surface.

Images