Short-wave infrared double-focal-length switching lens with preposed diaphragm and imaging method of short-wave infrared double-focal-length switching lens

Abstract

The invention relates to the technical field of optical imaging, in particular to a short-wave infrared double-focal-length switching lens with a preposed diaphragm and an imaging method, and the lens comprises the diaphragm, a long-focal-length lens group, a short-focal-length cut-in lens group and a target surface which are sequentially arranged along a light path direction. The long-focus lens group and the short-focus cut-in lens group form a short-focus lens group, and the short-focus cut-in lens group cuts in or out of a light path between the long-focus lens group and a target surface; through preposition of the diaphragm, pupil matching can be realized, a light beam divergence angle can be controlled, and butt joint with parallel light or a preposition telescope system is facilitated; by designing the short-focus cut-in lens group, the short-focus cut-in lens group is matched with the long-focus lens group to form the short-focus lens group, switching of long-focus and short-focus imaging requirements is realized by controlling cut-in or cut-out of the short-focus cut-in lens group, the structure is compact, the occupied space is small, and the requirements of high-end application fields for high-precision and high-reliability imaging are met.

Description

Technical Field

[0001] The present invention relates to the field of optical imaging technology, and in particular to a short-wave infrared dual-focal-segment switching lens with a front aperture and an imaging method. Background Art

[0002] Zoom lenses are increasingly used in shortwave infrared imaging. However, existing shortwave optical lenses often utilize traditional mechanical or optical structures to achieve zoom functionality. For example, some lenses achieve zoom by axially moving a lens group. This design is mechanically complex and requires a large number of lenses. Furthermore, the multiple refractions and reflections of light through the lens group increase energy loss, resulting in insufficient clarity and detail in the final image. Furthermore, switchable zoom lenses typically consist of two lens groups, requiring a large number of lenses and space for switching, which also results in relatively high costs.

[0003] In the context of current complex environments and diversified imaging needs, traditional short-wave optical lenses cannot meet the needs of high-end application fields for high-precision and high-reliability imaging in terms of zoom performance, imaging quality and energy utilization efficiency. Summary of the Invention

[0004] The purpose of the present invention is to provide a short-wave infrared dual-focus switching lens with a front aperture and an imaging method, so as to solve the technical problem that the current short-wave infrared dual-focus switching lens cannot meet the needs of high-end application fields.

[0005] The present invention solves the above-mentioned technical problems by: A short-wave infrared dual-focal-segment switching lens with a front diaphragm comprises an diaphragm, a long-focus lens group, a short-focus cut-in lens group, and a target surface, which are sequentially arranged along the optical path. The long-focus lens group and the short-focus cut-in lens group form a short-focus lens group, which cuts into or out of the optical path between the long-focus lens group and the target surface.

[0006] It is further defined that the telephoto fixed lens group includes a first light-transmitting mirror, a second light-transmitting mirror, a third light-transmitting mirror, a fourth light-transmitting mirror, a fifth light-transmitting mirror and a sixth light-transmitting mirror arranged in sequence along the light propagation direction; The first light-transmitting mirror is a positive-power meniscus lens, with its convex surface facing the image side; the second light-transmitting mirror is a negative-power meniscus lens, with its convex surface facing the image side; the third light-transmitting mirror is a positive-power meniscus lens, with its convex surface facing the image side; the fourth light-transmitting mirror is a positive-power biconvex lens; the fifth light-transmitting mirror is a positive-power biconvex lens; the sixth light-transmitting mirror is a negative-power meniscus lens, with its convex surface facing the image side.

[0007] It is further defined that the distance between the aperture and the front surface of the first light-transmitting mirror is 40 mm.

[0008] It is further defined that the first light-transmitting mirror is an H-ZF88 lens, the second light-transmitting mirror is an H-QK3L lens, the third light-transmitting mirror is an H-ZK9A lens, the fourth light-transmitting mirror is a CAF2 lens, the fifth light-transmitting mirror is an H-ZK9A lens, and the sixth light-transmitting mirror is an H-ZF88 lens.

[0009] It is further defined that the image distance of the telephoto fixed lens group is 167.0229 mm, and the focal length of the telephoto fixed lens group is 150 mm.

[0010] It is further defined that the short-focus cut-in lens group includes a seventh light-transmitting mirror, an eighth light-transmitting mirror, a ninth light-transmitting mirror, a tenth light-transmitting mirror and an eleventh light-transmitting mirror arranged in sequence along the light propagation direction; The seventh light-transmitting mirror is a positive-power meniscus lens, with the convex surface of the seventh light-transmitting mirror facing the image side; the eighth light-transmitting mirror is a negative-power meniscus lens with the convex surface facing the image side; the ninth light-transmitting mirror is a positive-power biconvex lens; the tenth light-transmitting mirror is a positive-power biconvex lens; and the eleventh light-transmitting mirror is a negative-power biconcave lens.

[0011] It is further defined that the seventh light-transmitting mirror is a positive-power meniscus lens with the convex surface facing the image side; the eighth light-transmitting mirror is a negative-power meniscus lens with the convex surface facing the image side; the ninth light-transmitting mirror is a positive-power biconvex lens; the tenth light-transmitting mirror is a positive-power biconvex lens; and the eleventh light-transmitting mirror is a negative-power biconcave lens.

[0012] It is further defined that the seventh light-transmitting mirror is an H-LAF3B lens; the eighth light-transmitting mirror is an H-ZPK5 lens; the ninth light-transmitting mirror is an H-ZK9A lens; the tenth light-transmitting mirror is an H-LAF3B lens; and the eleventh light-transmitting mirror is an H-ZF88 lens.

[0013] It is further defined that the image distance of the short-focus lens group is 30 mm, and the focal length of the short-focus lens group is 75 mm.

[0014] A method for imaging a short-wave infrared dual-focus switching lens with a pre-aperture diaphragm utilizes the above-mentioned short-wave infrared dual-focus switching lens with a pre-aperture diaphragm. The short-focus cut-in lens group cuts out the light path between the long-focus lens group and the target surface, and light sequentially passes through the diaphragm and the long-focus lens group to form a long-focus image on the target surface. Alternatively, the short-focus cut-in lens group cuts into the light path between the long-focus lens group and the target surface, and light sequentially passes through the diaphragm, the long-focus lens group, and the short-focus cut-in lens group to form a short-focus image on the target surface.

[0015] The beneficial effects of the present invention are: The present invention can achieve pupil matching and control the light beam divergence angle by placing the aperture in front, and is convenient for docking with parallel light or a front telescopic system; by designing a short-focus cut-in lens group, it is combined with a long-focus lens group to form a short-focus lens group, and the switching between long-focus and short-focus imaging requirements is achieved by controlling the short-focus cut-in lens group to cut in or out. The structure is compact and the space occupied is small, meeting the needs of high-end application fields for high-precision and high-reliability imaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic diagram of the imaging of the short-focus lens set described in Example 1 of the present invention; Figure 2 Schematic diagram of the imaging of the telephoto lens assembly according to Example 1 of the present invention; Figure 3 This is an MTF curve diagram of the imaging of a short-focus lens set with a spatial frequency of 33 lp / mm as described in Example 1 of the present invention; Figure 4 This is an MTF curve diagram of the imaging of a telephoto lens set with a spatial frequency of 33 lp / mm as described in Example 1 of the present invention; Figure 5 This is a point diagram of the image formed by the short-focus lens assembly described in Example 1 of the present invention; Figure 6 This is a point diagram of the image formed by the telephoto lens assembly described in Example 1 of the present invention; Figure 7 This is a diagram of the energy curve of the enclosing circle of the short-focus lens set imaged in Example 1 of the present invention. Figure 8 This is a diagram of the energy curve of the enclosing circle of the telephoto lens group imaged in Example 1 of the present invention. Figure 9 This is a schematic diagram of the imaging of the short-focus lens set described in Example 2 of the present invention; Figure 10 This is an MTF curve diagram of the imaging of a short-focus lens set with a spatial frequency of 33 lp / mm as described in Example 2 of the present invention; In the figure, 10-aperture; 20-telephoto lens group; 21-first light-transmitting mirror; 22-second light-transmitting mirror; 23-third light-transmitting mirror; 24-fourth light-transmitting mirror; 25-fifth light-transmitting mirror; 26-sixth light-transmitting mirror; 30-short-focus cutting-in lens group; 31-seventh light-transmitting mirror; 32-eighth light-transmitting mirror; 33-ninth light-transmitting mirror; 34-tenth light-transmitting mirror; 35-eleventh light-transmitting mirror; 40-target surface. DETAILED DESCRIPTION

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0018] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0019] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0020] In the description of the embodiments of the present invention, it should be noted that if the terms "upper," "lower," "horizontal," "inner," etc. appear, the orientation or positional relationship indicated is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the inventive product is typically placed when in use. These terms are merely for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or component referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first," "second," etc. are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0021] Example 1 refer to Figure 1 and Figure 2 The present invention provides a short-wave infrared dual-focal-segment switching lens with a pre-aperture aperture, comprising an aperture 10, a long-focus lens group 20, a short-focus cut-in lens group 30 and a target surface 40 arranged in sequence along the optical path; the long-focus lens group 20 and the short-focus cut-in lens group 30 constitute a short-focus lens group, and the short-focus cut-in lens group 30 cuts into or out of the optical path between the long-focus lens group 20 and the target surface 40, thereby realizing different imaging requirements of long focus and short focus. The overall structure is simple, the imaging accuracy is high, and the actual imaging requirements are met.

[0022] Specifically, refer to Figure 1 The telephoto fixed lens group 20 includes a first light-transmitting mirror 21, a second light-transmitting mirror 22, a third light-transmitting mirror 23, a fourth light-transmitting mirror 24, a fifth light-transmitting mirror 25 and a sixth light-transmitting mirror 26, which are sequentially arranged along the light propagation direction.

[0023] The first light-transmitting mirror 21 is a positive-power meniscus lens, with the convex surface of the first light-transmitting mirror 21 facing the image side; the second light-transmitting mirror 22 is a negative-power meniscus lens, with the convex surface of the second light-transmitting mirror 22 facing the image side; the third light-transmitting mirror 23 is a positive-power meniscus lens, with the convex surface facing the image side; the fourth light-transmitting mirror 24 is a positive-power biconvex lens; the fifth light-transmitting mirror 25 is a positive-power biconvex lens; the sixth light-transmitting mirror 26 is a negative-power meniscus lens, with the convex surface of the sixth light-transmitting mirror 26 facing the image side.

[0024] The distance between the diaphragm 10 and the front surface of the first light-transmitting mirror 21 is 40 mm. By placing the diaphragm 10 in front, pupil matching can be achieved, the light beam divergence angle can be controlled, and it is convenient to connect with the parallel light or front telescopic system.

[0025] Specifically, the parameters of each lens in the telephoto fixed lens group 20 are shown in Table 1: Table 1 Parameters of each lens in the telephoto fixed lens group

[0026] The image distance of the telephoto fixed lens group 20 is 167.0229 mm, and the focal length of the telephoto fixed lens group 20 is 150 mm.

[0027] For further explanation, see Figure 2 The short-focus cut-in lens group 30 includes a seventh light-transmitting mirror 31, an eighth light-transmitting mirror 32, a ninth light-transmitting mirror 33, a tenth light-transmitting mirror 34 and an eleventh light-transmitting mirror 35 arranged in sequence along the light propagation direction; The seventh light-transmitting mirror 31 is a positive-power meniscus lens, with its convex surface facing the image side; the eighth light-transmitting mirror 32 is a negative-power meniscus lens with its convex surface facing the image side; the ninth light-transmitting mirror 33 is a positive-power biconvex lens; the tenth light-transmitting mirror 34 is a positive-power biconvex lens; and the eleventh light-transmitting mirror 35 is a negative-power biconcave lens.

[0028] The seventh light-transmitting mirror 31 is a positive-power meniscus lens with its convex surface facing the image side; the eighth light-transmitting mirror 32 is a negative-power meniscus lens with its convex surface facing the image side; the ninth light-transmitting mirror 33 is a positive-power biconvex lens; the tenth light-transmitting mirror 34 is a positive-power biconvex lens; and the eleventh light-transmitting mirror 35 is a negative-power biconcave lens.

[0029] Specifically, the parameters of each lens in the short-focus cut-in lens group 30 are shown in Table 2: Table 2 Parameters of each lens in the short-focus cut-in lens group

[0030] During short-focus imaging, the short-focus cut-in lens group 30 is cut in to form a short-focus lens group with the long-focus lens group 20. At this time, the image distance of the short-focus lens group is 30 mm, and the focal length of the short-focus lens group is 75 mm.

[0031] Therefore, the short-wave infrared dual-focal-range switching lens optical system with a pre-aperture aperture provided in this embodiment has a short focal length of 75 mm, an entrance pupil diameter of 38 mm, an F-number of 1.97, and a field of view of 14.58°×11.69°; a long focal length of 150 mm, an entrance pupil diameter of 45 mm, an F-number of 3.33, and a field of view of 7.32°×5.86°; it is suitable for infrared detectors with a high resolution of 1280×1024 and a pixel size of 15µm, with a total length of 280 mm; and is also suitable for the current mainstream market resolution of 640×512.

[0032] Through the special optical power distribution and aberration correction design of the front 6 and rear 5 lens groups, the light is relatively smooth when switching focal lengths.

[0033] The short-focus cutting-in lens group 30 can choose to limit the cutting-in target position through mechanical limit, and the switching accuracy error is about 0.5mm~1mm, which can make the image plane almost without offset and ensure the imaging quality; at the same time, the large field of view can capture a wider scene; the larger relative aperture can provide better imaging effects under low light conditions and reduce noise; the combination of the two makes the image clear and adaptable to a variety of shooting environments.

[0034] The telephoto lens uses only 6 lenses, which reduces the number of light refractions and improves energy utilization. Figure 3 and Figure 4 When the spatial frequency is 33lp / mm, the MTF of the telephoto lens group 20 and the short-focus lens group are both better than 0.6, maintaining high contrast at the extreme resolution and meeting the requirements of high-resolution imaging.

[0035] refer to Figure 5 and Figure 6 From the system point diagram of the telephoto lens group 20 and the short-focus lens group, it can be seen that the maximum diffuse spot of the short-focus lens is 10.45μm, and the maximum diffuse spot of the telephoto lens is 15.8μm. The aberration correction is excellent and the imaging clarity is high.

[0036] refer to Figure 7 and Figure 8 From the energy curves of the encircling circles of the telephoto lens group 20 and the short-focus lens group, we can see that 93% of the encircling circle energy of the short-focus lens is concentrated in 2 pixels; 85% of the encircling circle energy of the telephoto lens is concentrated in 2 pixels, which reduces light energy loss and improves the signal-to-noise ratio, especially in low-light environments.

[0037] Example 2 Based on Example 1, reference Figure 9 This embodiment provides a short-wave infrared dual-focal length switching lens with a front aperture. When the short-focus lens group 30 is used for short-focus imaging, the cutting-in error is 1 mm.

[0038] refer to Figure 10Similarly, when the spatial frequency is 33lp / mm, the MTF of the short-focus lens group is still better than 0.6, meeting actual imaging needs.

[0039] Example 3 This embodiment provides an imaging method for a short-wave infrared dual-focal-length switching lens with a pre-aperture aperture. Based on the short-wave infrared dual-focal-length switching lens with a pre-aperture aperture described in Example 2, the short-focus entry lens group 30 cuts out the light path between the long-focus lens group 20 and the target surface 40, and the light passes through the aperture 10 and the long-focus lens group 20 in sequence to perform long-focus imaging on the target surface 40; alternatively, the short-focus entry lens group 30 cuts into the light path between the long-focus lens group 20 and the target surface 40, and the light passes through the aperture 10, the long-focus lens group 20 and the short-focus entry lens group 30 in sequence to perform short-focus imaging on the target surface 40.

[0040] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention. Therefore, from all points of view, the embodiments should be regarded as illustrative and non-restrictive. The scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes that fall within the meaning and range of equivalents of the claims are included in the present invention. Any reference signs in the claims should not be construed as limiting the claim to which they relate.

[0041] In addition, it should be understood that although this specification describes the embodiments, not every embodiment contains only one independent technical solution. This description is for clarity only. Those skilled in the art should consider the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art. The above content is only for the purpose of illustrating the technical concept of the present invention and cannot be used to limit the scope of protection of the present invention. Any changes made based on the technical solution in accordance with the technical concept proposed by the present invention fall within the scope of protection of the claims of the present invention.

[0042] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A short-wave infrared dual-focal-length switching lens with a front diaphragm, characterized in that: The invention comprises an aperture (10), a long-focus lens group (20), a short-focus cut-in lens group (30) and a target surface (40) arranged in sequence along the optical path; the long-focus lens group (20) and the short-focus cut-in lens group (30) form a short-focus lens group, and the short-focus cut-in lens group (30) cuts into or out of the optical path between the long-focus lens group (20) and the target surface (40).

2. The short-wave infrared dual-focal-length switching lens with a front aperture according to claim 1, characterized in that: The telephoto fixed lens group (20) comprises a first light-transmitting mirror (21), a second light-transmitting mirror (22), a third light-transmitting mirror (23), a fourth light-transmitting mirror (24), a fifth light-transmitting mirror (25), and a sixth light-transmitting mirror (26), which are sequentially arranged along the light propagation direction; The first light-transmitting mirror (21) is a positive-power meniscus lens, with the convex surface of the first light-transmitting mirror (21) facing the image side; the second light-transmitting mirror (22) is a negative-power meniscus lens, with the convex surface of the second light-transmitting mirror (22) facing the image side; the third light-transmitting mirror (23) is a positive-power meniscus lens, with the convex surface facing the image side; the fourth light-transmitting mirror (24) is a positive-power biconvex lens; the fifth light-transmitting mirror (25) is a positive-power biconvex lens; and the sixth light-transmitting mirror (26) is a negative-power meniscus lens, with the convex surface of the sixth light-transmitting mirror (26) facing the image side.

3. The short-wave infrared dual-focal-length switching lens with a front aperture according to claim 2, characterized in that: The distance between the aperture (10) and the front surface of the first light-transmitting mirror (21) is 40 mm.

4. The short-wave infrared dual-focal-length switching lens with a front aperture according to claim 2, characterized in that: The first light-transmitting mirror (21) is an H-ZF88 lens, the second light-transmitting mirror (22) is an H-QK3L lens, the third light-transmitting mirror (23) is an H-ZK9A lens, the fourth light-transmitting mirror (24) is a CAF2 lens, the fifth light-transmitting mirror (25) is an H-ZK9A lens, and the sixth light-transmitting mirror (26) is an H-ZF88 lens.

5. The short-wave infrared dual-focal-length switching lens with a front aperture according to claim 2, characterized in that: The image distance of the telephoto fixed lens group (20) is 167.0229 mm, and the focal length of the telephoto fixed lens group (20) is 150 mm.

6. The short-wave infrared dual-focus switching lens with a front aperture according to claim 1, characterized in that: The short-focus cut-in lens group (30) comprises a seventh light-transmitting mirror (31), an eighth light-transmitting mirror (32), a ninth light-transmitting mirror (33), a tenth light-transmitting mirror (34), and an eleventh light-transmitting mirror (35) arranged in sequence along the light propagation direction; The seventh light-transmitting mirror (31) is a positive-power meniscus lens, with the convex surface of the seventh light-transmitting mirror (31) facing the image side; the eighth light-transmitting mirror (32) is a negative-power meniscus lens, with the convex surface facing the image side; the ninth light-transmitting mirror (33) is a positive-power biconvex lens; the tenth light-transmitting mirror (34) is a positive-power biconvex lens; and the eleventh light-transmitting mirror (35) is a negative-power biconcave lens.

7. The short-wave infrared dual-focal-length switching lens with a front aperture according to claim 6, characterized in that: The seventh light-transmitting mirror (31) is a positive-power meniscus lens with a convex surface facing the image side; the eighth light-transmitting mirror (32) is a negative-power meniscus lens with a convex surface facing the image side; the ninth light-transmitting mirror (33) is a positive-power biconvex lens; the tenth light-transmitting mirror (34) is a positive-power biconvex lens; and the eleventh light-transmitting mirror (35) is a negative-power biconcave lens.

8. The short-wave infrared dual-focal-length switching lens with a front aperture according to claim 7, characterized in that: The seventh light-transmitting mirror (31) is an H-LAF3B lens; the eighth light-transmitting mirror (32) is an H-ZPK5 lens; the ninth light-transmitting mirror (33) is an H-ZK9A lens; the tenth light-transmitting mirror (34) is an H-LAF3B lens; and the eleventh light-transmitting mirror (35) is an H-ZF88 lens.

9. The short-wave infrared dual-focus switching lens with a front aperture according to claim 8, characterized in that: The image distance of the short-focus lens group is 30 mm, and the focal length of the short-focus lens group is 75 mm.

10. A short-wave infrared dual-focal-segment switching lens imaging method with a front-aperture stop, characterized in that: By using the short-wave infrared dual-focus switching lens with an aperture in front as described in any one of claims 1 to 9, the short-focus cutting-in lens group (30) cuts out the light path between the long-focus lens group (20) and the target surface (40), and the light passes through the aperture (10) and the long-focus lens group (20) in sequence to perform long-focus imaging on the target surface (40); or, the short-focus cutting-in lens group (30) cuts into the light path between the long-focus lens group (20) and the target surface (40), and the light passes through the aperture (10), the long-focus lens group (20) and the short-focus cutting-in lens group (30) in sequence to perform short-focus imaging on the target surface (40).

Images