Infrared double-view-field lens with short parfocal distance

Abstract

The utility model relates to an infrared double-view-field lens with a short parfocal distance, which comprises a main lens barrel and a plurality of lenses sequentially arranged in the main lens barrel from an object space to an image space, the first lens is movably arranged in the main lens barrel and is provided with a focusing driving mechanism for driving the first lens to move along the direction of an optical axis, and the second lens is provided with a second focusing driving mechanism for driving the second lens to move along the direction of the optical axis. The focusing driving mechanism is arranged on the main lens barrel. In the infrared double-view-field lens provided by the utility model, the first lens is used as a focusing group, namely, a first focusing mode is adopted, so that under the condition of realizing clear imaging of the lens at different temperatures and object distances, the parfocal distance of the double-view-field lens can be effectively shortened, and the application effect of the double-view-field lens and the use experience favorable sensitivity of a user are remarkably improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of infrared lenses, and particularly relates to an infrared dual-field lens with a short parfocal distance. Background Art

[0002] With the rapid development of infrared imaging technology, infrared dual-field lenses have been increasingly widely used. A dual-field lens has two working positions, namely a narrow field of view position and a wide field of view position, and can not only achieve short-focus large-field search but also achieve long-focus small-field locking. The existing dual-field lenses have a very large parfocal distance. For a conventional dual-field lens of f20 / 60, the parfocal distance is usually more than 50m, so that the parfocality below 50m is particularly poor, seriously affecting the application effect of the dual-field lens and the user's viewing experience. Summary of the Utility Model

[0003] The utility model relates to an infrared dual-field lens with a short parfocal distance, which can at least solve some defects of the prior art.

[0004] The utility model relates to an infrared dual-field lens with a short parfocal distance, including a main lens barrel and a plurality of lenses sequentially arranged in the main lens barrel from the object side to the image side. The first lens is movably arranged in the main lens barrel and is configured with a focusing drive mechanism for driving it to move along the optical axis direction. The focusing drive mechanism is arranged on the main lens barrel.

[0005] As one of the embodiments, a first lens, a second lens, a third lens, and a fourth lens are sequentially arranged in the main lens barrel from the object side to the image side, and the first lens is connected to the focusing drive mechanism.

[0006] As one of the embodiments, the second lens is movably arranged in the main lens barrel and is configured with a zoom switching mechanism for driving it to move along the optical axis direction. The zoom switching mechanism is arranged on the main lens barrel.

[0007] As one of the embodiments, the zoom switching mechanism includes a zoom ring, a curve barrel, and a guide pin. The curve barrel is rotatably assembled on the main lens barrel. The guide pin is connected to the second lens, passes through a guide groove on the main lens barrel, and is in sliding fit with a curve guide groove on the curve barrel. The zoom ring is sleeved outside the curve barrel and is connected to the curve barrel.

[0008] As one of the embodiments, the third lens is fixedly installed in the main lens barrel to form a first rear fixed group; the fourth lens is fixedly installed in the main lens barrel to form a second rear fixed group.

[0009] As one of the embodiments, the first lens has a positive diopter, its object side is convex, and its image side is concave;

[0010] The second lens has a negative refractive power, its object side is concave, and its image side is concave;

[0011] The third lens has a positive refractive power, its object side is convex, and its image side is convex or concave;

[0012] The fourth lens has a positive refractive power, its object side is convex, and its image side is concave or convex.

[0013] As one of the implementation manners, the image side of the first lens is an aspherical surface.

[0014] As one of the implementation manners, the object side of the second lens is an aspherical surface.

[0015] As one of the implementation manners, the object side of the third lens is a diffractive surface.

[0016] As one of the implementation manners, the focusing drive mechanism includes a focusing ring, and the focusing ring is threadedly connected to the lens frame of the first lens.

[0017] The present utility model has at least the following beneficial effects:

[0018] In the infrared dual-field-of-view lens provided by the present utility model, the first lens is used as the focusing group, that is, the first-lens focusing method is adopted. In the case of achieving clear imaging of the lens at different temperatures and object distances, the parfocal distance of the dual-field-of-view lens can be effectively shortened, and the application effect of the dual-field-of-view lens and the user's favorable impression of the use experience can be significantly improved. Description of the Drawings

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0020] Figure 1 It is a schematic structural diagram of the infrared dual-field-of-view lens provided by the embodiment of the present utility model;

[0021] Figure 2 For Figure 1 the lens combination schematic diagram in Detailed Embodiments

[0022] The technical solutions in the embodiments of the present utility model will be described clearly and completely below. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present utility model without creative efforts shall fall within the protection scope of the present utility model.

[0023] As Figure 1 and Figure 2 , an infrared dual-field-of-view lens with a short parfocal distance provided by an embodiment of the present utility model includes a main lens barrel 21 and a plurality of lenses sequentially arranged in the main lens barrel 21 from the object side to the image side. The first lens is movably arranged in the main lens barrel 21 and is configured with a focusing drive mechanism for driving it to move along the optical axis direction. The focusing drive mechanism is arranged on the main lens barrel 21.

[0024] In the above infrared dual-field-of-view lens, the first lens is used as the focusing group, that is, the first lens focusing method is adopted. In the case of achieving clear imaging of the lens at different temperatures and object distances, the parfocal distance of the dual-field-of-view lens can be effectively shortened, and the application effect of the dual-field-of-view lens and the user's favorability of the use experience can be significantly improved.

[0025] In this embodiment, the parfocal distance can reach 15 m.

[0026] The first lens, that is, the lens closest to the object side.

[0027] In one of the embodiments, as Figure 1 and Figure 2 , a first lens 11, a second lens 12, a third lens 13, and a fourth lens 14 are sequentially arranged in the main lens barrel 21 from the object side to the image side. Among them, the first lens 11 constitutes the above-mentioned first lens, and the first lens 11 is connected to the focusing drive mechanism.

[0028] Further, the second lens 12 is movably arranged in the main lens barrel 21 and is configured with a zoom switching mechanism for driving it to move along the optical axis direction. The zoom switching mechanism is arranged on the main lens barrel 21; that is, the second lens 12 is used as the zoom group.

[0029] Further, the third lens 13 is fixedly installed in the main lens barrel 21 to form a first rear fixed group;

[0030] The fourth lens 14 is fixedly installed in the main lens barrel 21 to form a second rear fixed group.

[0031] Based on the above lens combination of focusing group + zoom group + fixed group + fixed group, the imaging quality and application effect of the infrared dual-field-of-view lens can be guaranteed.

[0032] In one embodiment, as Figure 1 and Figure 2 , the first lens 11 has a positive diopter, its object side is convex, and its image side is concave;

[0033] The second lens 12 has a negative diopter, its object side is concave, and its image side is concave;

[0034] The third lens 13 has a positive diopter, its object side is convex, and its image side is convex or concave;

[0035] The fourth lens 14 has a positive diopter, its object side is convex, and its image side is concave or convex.

[0036] Based on the above lens design, the imaging quality can be improved.

[0037] Optionally, the image side of the first lens 11 is aspherical.

[0038] Optionally, the object side of the second lens 12 is aspherical.

[0039] Optionally, the object side of the third lens 13 is a diffractive surface.

[0040] Preferably, several of the above designs are adopted simultaneously, that is, the image side of the first lens 11 is aspherical, the object side of the second lens 12 is aspherical, and the object side of the third lens 13 is a diffractive surface, which can improve the imaging quality; among them, by designing the object side of the third lens 13 as a diffractive surface, through the coupled application of the aspherical surface and the diffractive surface, the aberration can be effectively corrected and the defocusing effect caused by temperature change can be compensated, thereby improving the imaging quality of the above infrared dual-field-of-view lens.

[0041] Optionally, in each lens, at least part of the lens is germanium glass, which can effectively improve the imaging quality.

[0042] In one embodiment, as Figure 1 , the focusing drive mechanism includes a focusing ring 22, and the focusing ring 22 is threadedly connected to the lens frame of the first lens.

[0043] In one embodiment, as Figure 1 , the zoom switching mechanism includes a zoom ring 23, a curved barrel 24 and a guide pin 25. The curved barrel 24 is rotatably assembled on the main lens barrel 21. The guide pin 25 is connected to the second lens 12, passes through the guide groove on the main lens barrel 21 and is slidably matched with the curved guide groove on the curved barrel 24. The zoom ring 23 is sleeved outside the curved barrel 24 and is connected to the curved barrel 24.

[0044] Preferably, the guiding groove on the main barrel 21 is a straight guiding groove parallel to the axis of the main barrel 21. The width of the straight guiding groove matches the diameter of the guiding pin 25, enabling the guiding pin 25 to slide linearly along the straight guiding groove. By guiding the guiding pin 25 through the straight guiding groove on the main barrel 21, the smoothness and accuracy of the linear movement of the second lens 12 are improved. Further, the guiding pin 25 includes a connecting portion and a guiding portion. The connecting portion is connected to the second lens 12, and the diameter of the guiding portion matches the width of the straight guiding groove and the width of the curved guiding groove, so that the guiding portion can slide along the straight guiding groove and the curved guiding groove. When the curved barrel 24 rotates about its own axis, the guiding pin 25 moves relative to the curved guiding groove of the curved barrel 24. At the same time, under the constraint of the straight guiding groove, the guiding pin 25 moves linearly, that is, drives the second lens 12 to move linearly, achieving the purpose of zooming. Further, multiple curved guiding grooves are provided on the curved barrel 24, and a guiding pin 25 is slidably disposed in each curved guiding groove. By the cooperation of the multiple curved guiding grooves and the multiple guiding pins 25, the smoothness and accuracy of the movement of the second lens 12 can be effectively improved. The zoom ring 23 and the curved barrel 24 include, but are not limited to, a threaded connection method.

[0045] Optionally, as Figure 1 , the outer wall diameter of the zoom ring 23 is the same as the outer wall diameter of the focusing ring 22. Since the zoom ring 23 and the focusing ring 22 are coaxial, they are coplanar, which can ensure the smoothness and aesthetics of the lens appearance and facilitate operation.

[0046] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An infrared dual-field lens with a short parfocal distance, comprising a main lens barrel and a plurality of lenses arranged in sequence from the object side to the image side in the main lens barrel, characterized in that: The first lens is movably arranged in the main lens barrel and is provided with a focus driving mechanism for driving the first lens to move along the optical axis direction. The focus driving mechanism is arranged on the main lens barrel.

2. The infrared dual-field-of-view lens according to claim 1, characterized in that: A first lens, a second lens, a third lens and a fourth lens are sequentially arranged in the main lens barrel from the object side to the image side, and the first lens is connected to the focus driving mechanism.

3. The infrared dual-field-of-view lens according to claim 2, characterized in that: The second lens is movably arranged in the main lens barrel and is provided with a magnification switching mechanism for driving the second lens to move along the optical axis. The magnification switching mechanism is arranged on the main lens barrel.

4. The infrared dual-field-of-view lens according to claim 3, characterized in that: The magnification switching mechanism includes a magnification ring, a curved cylinder and a guide pin. The curved cylinder is rotatably mounted on the main lens barrel. The guide pin is connected to the second lens, passes through the guide groove on the main lens barrel and slidably cooperates with the curved guide groove on the curved cylinder. The magnification ring is sleeved on the outside of the curved cylinder and is connected to the curved cylinder.

5. The infrared dual-field-of-view lens according to claim 2, characterized in that: The third lens is fixedly installed in the main lens barrel to form a first rear fixed group; The fourth lens is fixedly installed in the main lens barrel to form a second rear fixed group.

6. The infrared dual-field-of-view lens according to any one of claims 2 to 5, characterized in that: The first lens has positive refractive power, and its object side surface is convex and its image side surface is concave; The second lens has a negative refractive power, and its object side surface is concave, and its image side surface is concave; The third lens has positive refractive power, its object side surface is convex, and its image side surface is convex or concave; The fourth lens element has positive refractive power, an object side surface is convex, and an image side surface is concave or convex.

7. The infrared dual-field-of-view lens according to claim 6, characterized in that: The image side surface of the first lens is an aspherical surface.

8. The infrared dual-field-of-view lens according to claim 6, characterized in that: The object-side surface of the second lens is aspherical.

9. The infrared dual-field-of-view lens according to claim 6, characterized in that: The object-side surface of the third lens is a diffraction surface.

10. The infrared dual-field-of-view lens according to claim 1, characterized in that: The focus driving mechanism comprises a focus ring, and the focus ring is threadedly connected to the lens frame of the first lens.

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