CN218512709U - Athermal wide-angle infrared lens - Google Patents

Abstract

The utility model discloses an athermal wide-angle infrared lens, which comprises a first lens, a second lens and a third lens which are positioned in a main lens cone, wherein the first lens is a negative meniscus lens, the second lens and the third lens are double convex lenses, light rays sequentially enter the first lens, the second lens and the third lens from left to right along the direction of an optical axis, and finally enter a focal plane of a detector through a window of the detector; the interval distance between the adjacent surfaces of the first lens and the second lens is 11.60mm; the interval distance between the adjacent surfaces of the second lens and the third lens is 10.89mm; a diaphragm is arranged between the second lens and the third lens, and the separation distance between the diaphragm and the second lens is 3.44mm; the utility model discloses a under the long wave detection wave band, the focus is 13 mm's wide angle infrared camera lens, and the camera lens satisfies the athermal design, simple structure is compact, light in weight, and easy installation easily realizes standardized batch production.

Description

Athermal wide-angle infrared lens

Technical Field

The utility model relates to an infrared lens specifically is an athermal wide angle infrared lens.

Background

The infrared lens is matched with an infrared refrigeration detector, is used for a night monitoring system without an auxiliary light source, and is widely applied to the industries of security, industry, medical treatment and the like from military to civil use; the infrared detection technology has the characteristics of good anti-interference performance, longer night action distance, strong smoke and haze penetrating capability, capability of working day and night, and strong capability of being suitable for various weathers.

However, the design of the existing athermalized wide-angle infrared lens is not optimized and needs to be further improved.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide an athermal wide angle infrared lens to solve the problem that proposes in the above-mentioned background art.

In order to achieve the above object, the utility model provides a following technical scheme:

the utility model provides an athermal wide angle infrared lens, is including first lens, second lens and the third lens that is located the main lens cone, first lens is negative meniscus lens, second lens, third lens are biconvex lens, and light is followed optical axis direction from left to right and is incided first lens, second lens, third lens in proper order, incides the detector focal plane through the detector window at last.

As a further aspect of the present invention: the distance between the adjacent surfaces of the first lens and the second lens is 11.60mm.

As a further aspect of the present invention: the distance between the adjacent surfaces of the second lens and the third lens is 10.89mm.

As a further aspect of the present invention: and a diaphragm is arranged between the second lens and the third lens, and the spacing distance between the diaphragm and the second lens is 3.44mm.

As the utility model discloses further scheme again: the first lens, the second lens and the third lens are all made of germanium.

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

the utility model discloses a under the wave band is surveyed to the long wave, the focus is 13 mm's wide angle infrared camera lens, and the camera lens satisfies no thermalization design, simple structure is compact, light in weight, and easy installation easily realizes standardized batch production.

Drawings

Fig. 1 is a schematic structural diagram of an athermal wide-angle infrared lens.

The lens system comprises a first lens 1, a second lens 2 and a third lens 3.

Detailed Description

In order to make the technical problem, technical scheme and the beneficial effect that the utility model will solve clearer and more understand, will combine the embodiment below, it is right to the utility model discloses further detail explanation. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

It will be understood that when an element is referred to as being "secured to" 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 will be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", and the like, are used in the orientation or positional relationship indicated in the drawings for convenience in describing the invention and to simplify the description, and do not indicate or imply that the device or element so referred to must have the orientation, configuration, and operation specified in the specification and therefore should not be construed as limiting the invention.

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

Referring to fig. 1, in an embodiment of the present invention, an athermal wide-angle infrared lens includes a first lens 1, a second lens 2 and a third lens 3 which are located in a main lens barrel, the first lens 1 is a negative meniscus lens, the second lens 2 and the third lens 3 are biconvex lenses, light sequentially enters the first lens 1, the second lens 2 and the third lens 3 from left to right along an optical axis direction, and finally enters a focal plane of a detector through a detector window, and stepped steps are used in the main lens barrel for ensuring intervals of the lenses, a lens space ring structure is used between the lenses, and three lenses are fixed at the rear end of the third lens 3 by using a screw thread pressing ring.

The distance between the adjacent surfaces of the first lens 1 and the second lens 2 is 11.60mm.

The adjacent surfaces of the second lens 2 and the third lens 3 are separated by a distance of 10.89mm.

A diaphragm 4a is arranged between the second lens 2 and the third lens 3, and the distance between the diaphragm 4a and the second lens 2 is 3.44mm.

The first lens element 1, the second lens element 2 and the third lens element 3 are all made of germanium.

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

TABLE 1

Wherein the aspheric surface satisfies the following formula:

wherein Z is a distance from a vertex of the aspherical surface when the aspherical surface is at a position having a height R in the optical axis direction, c =1/R, and R represents a paraxial radius of curvature of the mirror surface; k is a cone coefficient; a, B, C and D are high-order aspheric coefficients.

The utility model discloses in the imaging quality that the camera lens was realized is as follows:

a)MTF：

at normal temperature of 20 ℃: at the spatial frequency of 30lp/mm, the MTF of the central 0.7 visual field is more than 0.55, and the MTF of the edge visual field is more than 0.46; low temperature-40 ℃: at the spatial frequency of 30lp/mm, the MTF of the central 0.7 visual field is more than 0.45, and the MTF of the edge visual field is more than 0.35;

high temperature +60 ℃: at the spatial frequency of 30lp/mm, the MTF of the central 0.7 view field is greater than 0.5, and the edge view field is greater than 0.4;

b) Dispersion characteristics: optical imaging dispersion characteristics are shown in tables 2, 3 and 4:

visual field	1	2	3	4	5	6	7	8	9
										RMS radius μm	4.221	7.068	7.068	6.145	5.906	7.692	5.906	5.491	6.461
GEO radius μm	6.499	26.584	26.584	14.768	14.916	25.522	14.916	13.447	13.243

Table 2: dispersion property at room temperature of 20 DEG C

Visual field	1	2	3	4	5	6	7	8	9
										RMS radius μm	3.964	12.696	12.696	5.341	6.193	15.182	6.193	4.933	7.451
GEO radius μm	9.230	32.751	32.751	12.517	12.992	39.996	12.992	12.611	18.011

Table 3: low temperature-40 ℃ dispersion characteristics

Field of view	1	2	3	4	5	6	7	8	9
										RMS radius μm	6.493	8.424	8.424	8.424	8.452	7.246	8.452	7.719	9.223
GEO radius μm	11.423	24.316	24.316	22.646	26.697	23.115	26.697	19.967	21.959

Table 4: high temperature +60 ℃ dispersion characteristics

c) Distortion characteristics: under the temperature condition of minus 40 ℃ to plus 60 ℃, the maximum distortion of the imaging is not more than 5 percent.

In conclusion, the utility model can satisfy the environmental temperature within the range of-40 ℃ to 60 ℃ by adjusting the rear intercept of the lens through athermal optimization, and can keep high-quality image quality.

Although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that modifications may be made to the embodiments or portions thereof without departing from the spirit and scope of the invention.

Claims (5)

1. An athermal wide-angle infrared lens, comprising: including first lens (1), second lens (2) and third lens (3) that are located the main lens cone, first lens (1) is negative meniscus lens, second lens (2), third lens (3) are biconvex lens, be provided with the diaphragm between second lens (2) and third lens (3), first lens (1), second lens (2), third lens (3) are incited from left to right in proper order along the optical axis direction to light, incite the detector focal plane through the detector window at last, aspheric surface in first lens (1), second lens (2), third lens (3) satisfies following formula:

wherein Z is a distance from a vertex of the aspherical surface when the aspherical surface is at a position having a height R in the optical axis direction, c =1/R, and R represents a paraxial radius of curvature of the mirror surface; k is a cone coefficient; a, B, C and D are high-order aspheric coefficients.

2. The athermal wide-angle ir lens of claim 1, wherein: the interval distance between the adjacent surfaces of the first lens (1) and the second lens (2) is 11.60mm.

3. The athermal wide-angle infrared lens of claim 1, wherein: the distance between the adjacent surfaces of the second lens (2) and the third lens (3) is 10.89mm.

4. The athermal wide-angle ir lens of claim 1, wherein: the distance between the diaphragm and the second lens (2) is 3.44mm.

5. The athermal wide-angle ir lens of claim 1, wherein: the first lens (1), the second lens (2) and the third lens (3) are all made of germanium.

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