Infrared double-view-field lens
By designing a second lens with both zooming and focus functions, the clear imaging of infrared dual-field lenses during field switching is achieved, which solves the problem of cumbersome operation in the prior art, simplifies the lens structure and improves the user experience.
Patent Information
- Application Number
- CN202422209843.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-10
- Publication Date
- 2025-06-24
- Estimated Expiration
- 2034-09-10
AI Technical Summary
When switching between the field of view of existing infrared dual-field lenses, they need to rotate the zoom group and the focus group, which is cumbersome to operate and reduce the user experience.
An infrared dual-field lens is designed, with only one set of lenses movable, that is, the second lens has both zoom and focus functions, and field switching and focus can be achieved through the zoom and focus driving mechanism.
With only one set of lenses rotating, clear imaging of dual-field lenses at field switching, high and low temperatures, and different object distances is achieved, simplifying the lens structure, reducing equipment costs, and improving user experience.
Smart Images
Figure CN223022444U_ABST
Abstract
Description
Technical Field
[0001] The utility model belongs to the technical field of infrared lenses, and particularly relates to an infrared dual-field-of-view lens. Background Technique
[0002] With the rapid development of infrared imaging technology, infrared dual-field-of-view lenses have been increasingly widely used. The dual-field-of-view lens has two working positions, namely the narrow field of view position and the wide field of view position, and can not only achieve short-focus large-field-of-view search but also long-focus small-field-of-view locking. At present, the dual-field-of-view lens needs to be configured with a zoom group and a focusing group. The zoom group is used to realize the field-of-view switching, and the focusing group is used for focusing. This lens structure is complex. When the field of view is switched, after rotating the zoom group, it is necessary to rotate the focusing group again, and the operation is cumbersome, which will reduce the user experience. Content of the Utility Model
[0003] The utility model relates to an infrared dual-field-of-view lens, which can at least solve some defects of the prior art.
[0004] The utility model relates to an infrared dual-field-of-view lens, including a main lens barrel and a first lens, a second lens, a third lens, and a fourth lens sequentially arranged in the main lens barrel from the object side to the image side.
[0005] The first lens is fixedly installed in the main lens barrel to form a front fixed group.
[0006] The second lens is movably arranged in the main lens barrel and is configured with a zoom and focusing drive mechanism for driving it to move along the optical axis direction. The zoom and focusing drive mechanism is arranged on the main lens barrel.
[0007] The third lens is fixedly installed in the main lens barrel to form a first rear fixed group.
[0008] 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 a convex surface, and its image side is a concave surface.
[0010] The second lens has a negative diopter, its object side is a concave surface, and its image side is a concave surface.
[0011] The third lens has a positive diopter, its object side is a convex surface, and its image side is a convex surface or a concave surface.
[0012] The fourth lens has a positive diopter, its object side is a convex surface or a concave surface, and its image side is a convex surface.
[0013] As one of the embodiments, the image side of the first lens is an aspherical surface.
[0014] As one of the implementation manners, the object side surface of the second lens is an aspherical surface.
[0015] As one of the implementation manners, the aspherical surface type is an even-order aspherical surface type, which is represented by the following equation:
[0016]
[0017] Where z is the axial sag height of the aspherical surface in the Z direction; r is the distance from a point on the aspherical surface to the optical axis; c is the curvature of the fitted spherical surface, numerically the reciprocal of the radius of curvature; k is the fitted conic coefficient; A to E are the coefficients of the 2nd, 4th, 6th, 8th, and 10th order terms of the polynomial respectively.
[0018] As one of the implementation manners, the object side surface and / or the image side surface of the third lens is a diffractive spherical surface.
[0019] As one of the implementation manners, the surface type of the diffractive spherical surface is a binary surface, which is represented by the following equation:
[0020]
[0021]
[0022] Where z is the axial sag height of the diffractive surface in the Z direction; r is the distance from a point on the diffractive surface to the optical axis; c is the curvature of the fitted spherical surface, numerically the reciprocal of the radius of curvature; k is the fitted conic coefficient; A to E are the coefficients of the 2nd, 4th, 6th, 8th, and 10th order terms of the polynomial respectively; λ0 is the central wavelength of the infrared light, and the central wavelength range is 8 - 14 μm; n0 is the refractive index corresponding to the central wavelength; HOR represents the horizontal angle; M is the diffraction order; N is the order of the polynomial coefficient in the series; Ai is the coefficient of the 2i-th power; ρ is the normalized radial aperture coordinate.
[0023] As one of the implementation manners, a diaphragm is provided on the image side surface or the object side surface of the third lens, or the diaphragm is located within 5 mm from the front surface or the rear surface of the third lens.
[0024] As one of the implementation manners, the first lens, the second lens, the third lens, and the fourth lens are all germanium single crystal lenses.
[0025] As one of the implementation manners, the lens range is 8 - 14 μm.
[0026] The utility model has at least the following beneficial effects:
[0027] In the infrared dual-field-of-view lens provided by the present utility model, only one set of lenses is movable, that is, the second lens mentioned above combines the functions of zooming and focusing, and realizes clear imaging of the dual-field-of-view lens under field-of-view switching, high and low temperatures, and different object distances by only rotating one set of lenses; compared with the traditional infrared dual-field-of-view lens, the above-mentioned infrared dual-field-of-view lens can effectively simplify the lens structure, reduce the equipment cost, and improve the user experience favorability due to reducing the movement of one set of lenses. BRIEF DESCRIPTION OF THE DRAWINGS
[0028] 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 drawings in the following description are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.
[0029] Figure 1 It is a schematic structural diagram of an infrared dual-field-of-view lens provided by an embodiment of the present utility model;
[0030] Figure 2 is Figure 1 a schematic diagram of the lens combination in DETAILED DESCRIPTION OF THE EMBODIMENTS
[0031] The following clearly and completely describes the technical solutions in the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, rather than all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the protection scope of the present utility model.
[0032] As Figure 1 and Figure 2 , an embodiment of the present utility model provides an infrared dual-field-of-view lens, including a main lens barrel 20 and a first lens 11, a second lens 12, a third lens 13, and a fourth lens 14 sequentially arranged in the main lens barrel 20 from the object side to the image side,
[0033] The first lens 11 is fixedly installed in the main lens barrel 20 to form a front fixed group;
[0034] The second lens 12 is movably arranged in the main lens barrel 20 and is configured with a zoom and focus drive mechanism 21 for driving it to move along the optical axis direction. The zoom and focus drive mechanism 21 is arranged on the main lens barrel 20;
[0035] The third lens 13 is fixedly installed in the main lens barrel 20 to form a first rear fixed group;
[0036] The fourth lens 14 is fixedly installed in the main barrel 20 to form a second rear fixed group.
[0037] In the above infrared dual-field-of-view lens, only one group of lenses is movable. That is, the second lens 12 combines the functions of zooming and focusing, and realizes clear imaging of the dual-field-of-view lens under field-of-view switching, high and low temperatures, and different object distances by only rotating one group of lenses. Compared with the traditional infrared dual-field-of-view lens, the above infrared dual-field-of-view lens can effectively simplify the lens structure, reduce the equipment cost, and improve the user experience favorability due to the reduction of the movement of one group of lenses.
[0038] Preferably, the lens range of the above infrared dual-field-of-view lens is 8-14 μm.
[0039] In the above infrared dual-field-of-view lens, under the action of the zoom and focus drive mechanism 21, the second lens 12 has a narrow field-of-view position and a wide field-of-view position. At the narrow field-of-view position and the wide field-of-view position, the second lens 12 is rotated by the zoom and focus drive mechanism 21 respectively to complete the focusing action, so that zooming and focusing operations can be realized. Therefore, in addition to the narrow field-of-view position and the wide field-of-view position, the second lens 12 also has a first focusing position near the narrow field-of-view position and a second focusing position near the wide field-of-view position. The first focusing position and the second focusing position may change with the change of imaging conditions and the like. When designing the position adjustment stroke of the second lens 12, the stroke endpoints are traditionally designed to match the narrow field-of-view position and the wide field-of-view position. In this application, a certain focusing stroke can be added on the basis of the stroke points corresponding to the narrow field-of-view position and the wide field-of-view position. In this application, although some sacrifices are made in the accuracy of field-of-view switching, it can effectively simplify the lens structure and improve the user experience degree under the condition of meeting the requirements of clear imaging, and has very good application reliability in scenarios with non-high-precision imaging requirements.
[0040] 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;
[0041] The second lens 12 has a negative diopter, its object side is concave, and its image side is concave;
[0042] The third lens 13 has a positive diopter, its object side is convex, and its image side is convex or concave;
[0043] The fourth lens 14 has a positive diopter, its object side is convex or concave, and its image side is convex.
[0044] Based on the above lens design, the imaging quality can be improved.
[0045] Optionally, the image side of the first lens 11 is aspherical.
[0046] Optionally, the object side surface of the second lens 12 is an aspherical surface.
[0047] Further preferably, the surface profile of the above-mentioned aspherical surface is an even-order aspherical surface profile, and is represented by the following equation:
[0048]
[0049] Where, z is the axial sag of the aspherical surface in the Z direction; r is the distance from a point on the aspherical surface to the optical axis; c is the curvature of the fitted spherical surface, numerically the reciprocal of the radius of curvature; k is the fitted conic coefficient; A to E are the coefficients of the 2nd, 4th, 6th, 8th, and 10th order terms of the polynomial respectively.
[0050] Adopting the above lens design can effectively improve the imaging quality.
[0051] Optionally, the object side surface and / or the image side surface of the third lens 13 is a diffractive spherical surface.
[0052] Further preferably, the surface profile of the above-mentioned diffractive spherical surface is a binary surface, and is represented by the following equation:
[0053]
[0054]
[0055] Where, z is the axial sag of the diffractive surface in the Z direction; r is the distance from a point on the diffractive surface to the optical axis; c is the curvature of the fitted spherical surface, numerically the reciprocal of the radius of curvature; k is the fitted conic coefficient; A to E are the coefficients of the 2nd, 4th, 6th, 8th, and 10th order terms of the polynomial respectively; λ0 is the central wavelength of the infrared light, and the central wavelength range is 8 - 14 μm; n0 is the refractive index corresponding to the central wavelength; HOR represents the horizontal angle; M is the diffraction order; N is the order of the polynomial coefficient in the series; Ai is the coefficient of the 2i-th power; ρ is the normalized radial aperture coordinate.
[0056] Adopting the above lens design can effectively improve the imaging quality.
[0057] It is preferably to adopt several of the above designs simultaneously, that is, the image side surface of the first lens 11 is an aspherical surface, the object side surface of the second lens 12 is an aspherical surface, and the object side surface and / or the image side surface of the third lens 13 is a diffractive spherical surface, which can improve the imaging quality; among them, designing the object side surface and / or the image side surface of the third lens 13 as a diffractive spherical surface can effectively correct aberration and compensate for the defocusing effect caused by temperature change through the coupled application of the aspherical surface and the diffractive spherical surface, and improve the imaging quality of the above infrared dual-field-of-view lens.
[0058] In one embodiment, a diaphragm is provided on the image side or the object side of the third lens 13, or the diaphragm is located within 5 mm from the front surface or the rear surface of the third lens, which can further improve the imaging quality.
[0059] Optionally, the first lens 11, the second lens 12, the third lens 13, and the fourth lens 14 are all germanium single crystal lenses, which can effectively improve the imaging quality.
[0060] In one embodiment, as Figure 1 , the zoom and focus drive mechanism 21 includes a focus adjustment cylinder and a guide pin. The focus adjustment cylinder is rotatably sleeved on the main lens barrel 20. The guide pin is connected to the second lens 12, passes through the guide groove on the main lens barrel 20, and is slidably engaged with the curved guide groove on the focus adjustment cylinder.
[0061] Preferably, the guide groove on the main lens barrel 20 is a straight guide groove parallel to the axis of the main lens barrel. The groove width of the straight guide groove matches the diameter of the guide pin, so that the guide pin can slide linearly along the straight guide groove. By guiding the guide pin through the straight guide groove on the main lens barrel 20, the smoothness and accuracy of the linear movement of the second lens 12 are improved. Further, the focus adjustment cylinder is provided with a curved guide groove. The guide pin includes a connecting portion and a guiding portion. The connecting portion is connected to the second lens 12. The diameter of the guiding portion matches the groove width of the straight guide groove and the groove width of the curved guide groove, so that the guiding portion can slide along the straight guide groove and the curved guide groove. When the focus adjustment cylinder rotates around its own axis, the guide pin moves relative to the curved guide groove of the focus adjustment cylinder. At the same time, under the constraint of the straight guide groove, the guide pin makes a linear movement, that is, drives the second lens 12 to make a linear movement to achieve the purpose of focusing. Further, the focus adjustment cylinder is provided with a plurality of curved guide grooves, and each curved guide groove is slidably provided with a guide pin. Through the cooperation of the plurality of curved guide grooves and the plurality of guide pins, the smoothness and accuracy of the movement of the second lens 12 can be effectively improved.
[0062] The above-mentioned second lens 12 is assembled in a corresponding lens frame, and the lens frame is slidably arranged in the main lens barrel 20, for example, it is in clearance fit with the inner wall of the main lens barrel 20. The above-mentioned guide pin is connected to the lens frame.
[0063] In one embodiment, the above-mentioned infrared dual-field-of-view lens further includes a detection unit for realizing focal length detection. By feeding back the focal length in real time through this detection unit, the focusing accuracy can be guaranteed and the imaging quality can be improved. The detection unit includes, but is not limited to, a potentiometer, a Hall sensor, etc. For example, in a Hall sensor and a magnet cooperating therewith, one of the devices is installed on the above-mentioned focus adjustment cylinder, and the other device is installed on the main lens barrel 20.
[0064] The above are only the preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.
Claims
1. An infrared dual-field lens, comprising a main lens barrel and a first lens, a second lens, a third lens and a fourth lens arranged in the main lens barrel in sequence from the object side to the image side, characterized in that: The first lens is fixedly installed in the main lens barrel to form a front fixed group; The second lens is movably arranged in the main lens barrel and is provided with a variable magnification and focusing driving mechanism for driving the second lens to move along the optical axis, and the variable magnification and focusing driving mechanism is arranged on the main lens barrel; 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.
2. The infrared dual-field-of-view lens according to claim 1, 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 thereof is convex or concave, and an image side surface is convex.
3. The infrared dual-field-of-view lens according to claim 2, characterized in that: The image side surface of the first lens is an aspherical surface.
4. The infrared dual-field-of-view lens according to claim 2, characterized in that: The object-side surface of the second lens is aspherical.
5. The infrared dual-field-of-view lens according to claim 3 or 4, characterized in that: The aspheric surface type is an even aspheric surface type, which is expressed by the following equation: Among them, z is the axial vector height of the aspheric surface in the Z direction; r is the distance from the point on the aspheric surface to the optical axis; c is the curvature of the fitted sphere, which is the reciprocal of the radius of curvature; k is the fitted cone coefficient; A~E are the coefficients of the 2nd, 4th, 6th, 8th, and 10th order terms of the polynomial, respectively.
6. The infrared dual-field-of-view lens according to claim 2, characterized in that: The object side surface and / or the image side surface of the third lens is a diffractive spherical surface.
7. The infrared dual-field-of-view lens according to claim 6, characterized in that: The surface shape of the diffraction spherical surface is a two-dimensional surface, which is expressed by the following equation: Among them, z is the axial vector height of the diffraction surface in the Z direction; r is the distance from the point on the diffraction surface to the optical axis; c is the curvature of the fitted sphere, which is the inverse of the radius of curvature; k is the fitted cone coefficient; A~E are the coefficients of the 2nd, 4th, 6th, 8th, and 10th order terms of the polynomial, respectively; λ0 is the central wavelength of infrared light, and the central wavelength range is 8-14μm; n0 is the refractive index corresponding to the central wavelength; HOR represents the horizontal angle; M is the diffraction order; N is the order of the polynomial coefficients in the series; Ai is the coefficient of the 2ith power; ρ is the normalized radial aperture coordinate.
8. The infrared dual-field-of-view lens according to claim 1 or 2, characterized in that: An aperture stop is provided on the image side surface or the object side surface of the third lens, or the aperture stop is located within 5 mm from the front surface or the rear surface of the third lens.
9. The infrared dual-field-of-view lens according to claim 1 or 2, characterized in that: The first lens, the second lens, the third lens and the fourth lens are all germanium single crystal lenses.
10. The infrared dual-field-of-view lens according to claim 1, characterized in that: The lens range is 8~14μm.