Observing and aiming lens

Abstract

The utility model discloses an observing and aiming lens, which sequentially comprises a first lens with positive diopter, a second lens with negative diopter, a third lens with positive diopter and a fourth lens with negative diopter from an object side to an image side along an optical axis, the image side surface of the second lens is a concave surface; the object side surface of the third lens is a convex surface; the image side surface of the fourth lens is a concave surface; the fifth lens has positive diopter, and the object side surface and the image side surface of the fifth lens are convex surfaces; the sixth lens has negative diopter, and the object side surface and the image side surface of the sixth lens are concave surfaces; a seventh lens having a diopter; and an eighth lens having a diopter. Wherein the effective focal length f7 of the seventh lens and the total effective focal length f of the observing and aiming lens meet the condition that f7 / f is larger than or equal to 0.15 and smaller than or equal to 0.60.

Description

Technical Field

[0001] The present application relates to the field of optical devices, and in particular to a sighting lens. Background Art

[0002] As an important component of photographic equipment, the sighting lens is widely used in various photographic scenes. With the increase in application scenarios, the requirements for sighting lenses also increase. The sighting lens is a handheld device that pays more attention to portability, which requires the sighting lens to have a sufficiently small weight and volume to achieve miniaturization. When using the sighting lens to observe the details of an object, the sighting lens needs to have a small object field of view and a long focal length, and in order to meet the needs of distinguishing tiny details, the sighting lens must also have high image quality. In addition, in order to meet the needs of night observation, the sighting lens needs to achieve infrared confocality. However, it is difficult for existing sighting lenses to achieve small aperture and high image quality at the same time, and it is also difficult to achieve telephoto and a small total optical length at the same time. The existing sighting lens has a narrow operating band, making it difficult to achieve infrared confocality. Utility Model Content

[0003] The present application provides a sighting lens that can at least solve or partially solve at least one problem or other problems existing in the prior art.

[0004] One aspect of the present application provides a viewing and aiming lens, which includes, in order from the object side to the image side along the optical axis: a first lens with positive refractive power, whose object side surface is convex; a second lens with negative refractive power, whose image side surface is concave; a third lens with positive refractive power, whose object side surface is convex; a fourth lens with negative refractive power, whose image side surface is concave; a fifth lens with positive refractive power, whose object side surface and image side surface are both convex; a sixth lens with negative refractive power, whose object side surface and image side surface are both concave; a seventh lens with refractive power; and an eighth lens with refractive power; wherein the effective focal length f7 of the seventh lens and the total effective focal length f of the viewing and aiming lens satisfy: 0.15≤|f7 / f|≤0.60.

[0005] According to an exemplary embodiment of the present application, the seventh lens has positive refractive power, and the object side surface and the image side surface of the seventh lens are both convex surfaces; or, the seventh lens has negative refractive power, the object side surface of the seventh lens is convex, and the image side surface of the seventh lens is concave.

[0006] According to an exemplary embodiment of the present application, the eighth lens has positive refractive power, the object-side surface of the eighth lens is convex, and the image-side surface of the eighth lens is concave; or, the eighth lens has negative refractive power, and the object-side surface of the eighth lens is concave.

[0007] According to an exemplary embodiment of the present application, the maximum full aperture Dmax of the sighting and aiming lens and the total optical length TTL of the sighting and aiming lens satisfy the following: 0.45≤Dmax / TTL≤0.53.

[0008] According to an exemplary embodiment of the present application, the total optical length TTL of the viewing and aiming lens and the total effective focal length f of the viewing and aiming lens satisfy: 0.85≤TTL / f≤1.00.

[0009] According to an exemplary embodiment of the present application, the total effective focal length f of the viewing and aiming lens and the entrance pupil diameter ENPD of the viewing and aiming lens satisfy: 2.10≤f / ENPD≤2.30.

[0010] According to an exemplary embodiment of the present application, the back focal length BFL of the sighting and aiming lens and the total optical length TTL of the sighting and aiming lens satisfy: 0.15≤BFL / TTL≤0.35.

[0011] According to an exemplary embodiment of the present application, the effective focal length f1 of the first lens and the total effective focal length f of the aiming and viewing lens satisfy: 0.55≤f1 / f≤1.20.

[0012] According to an exemplary embodiment of the present application, the effective focal length f2 of the second lens and the total effective focal length f of the aiming lens satisfy: -1.30≤f2 / f≤-0.50.

[0013] According to an exemplary embodiment of the present application, the effective focal length f3 of the third lens and the total effective focal length f of the aiming lens satisfy: 0.30≤f3 / f≤1.00.

[0014] According to an exemplary embodiment of the present application, the effective focal length f4 of the fourth lens and the total effective focal length f of the aiming lens satisfy: -0.95≤f4 / f≤-0.45.

[0015] According to an exemplary embodiment of the present application, the effective focal length f5 of the fifth lens and the total effective focal length f of the aiming lens satisfy: 0.25≤f5 / f≤0.65.

[0016] According to an exemplary embodiment of the present application, the effective focal length f6 of the sixth lens and the total effective focal length f of the aiming lens satisfy: -0.70≤f6 / f≤-0.15.

[0017] According to an exemplary embodiment of the present application, the effective focal length f8 of the eighth lens and the total effective focal length f of the aiming lens satisfy: 0.20≤|f8 / f|≤0.70.

[0018] According to an exemplary embodiment of the present application, three adjacent lenses among the second to sixth lenses are cemented to form a triplet lens, and the effective focal length fa of the triplet lens and the total effective focal length f of the sighting lens satisfy: 1.10≤|fa / f|≤5.10.

[0019] According to an exemplary embodiment of the present application, two adjacent lenses among the second to sixth lenses are cemented to form a doublet lens, and the effective focal length fb of the doublet lens and the total effective focal length f of the sighting lens satisfy: 0.50≤|fb / f|≤3.75.

[0020] According to an exemplary embodiment of the present application, the combined focal length F1 of the first lens to the sixth lens and the total effective focal length f of the aiming lens satisfy: 0.75≤|F1 / f|≤1.35.

[0021] According to an exemplary embodiment of the present application, the combined focal length F2 of the seventh lens and the eighth lens and the total effective focal length f of the aiming lens satisfy: 1.10≤|F2 / f|≤9.85.

[0022] According to an exemplary embodiment of the present application, the combined focal length F1 of the first to sixth lenses and the combined focal length F2 of the seventh and eighth lenses satisfy: 0.05≤|F1 / F2|≤0.85.

[0023] According to an exemplary embodiment of the present application, a curvature radius R72 of the image-side surface of the seventh lens and a curvature radius R81 of the object-side surface of the eighth lens satisfy: -0.35≤(R72-R81) / (R72+R81)≤0.45.

[0024] According to an exemplary embodiment of the present application, the Abbe number VD1 of the first lens satisfies: 65≤VD1≤100.

[0025] According to an exemplary embodiment of the present application, the Abbe number VD3 of the third lens satisfies: 90≤VD3≤100.

[0026] According to an exemplary embodiment of the present application, the Abbe number VD5 of the fifth lens satisfies: 65≤VD5≤100.

[0027] The present application adopts eight lenses. By reasonably allocating the refractive power of each lens and matching a reasonable ratio of the effective focal length of the seventh lens to the total effective focal length of the sighting lens, the sighting lens can achieve at least one beneficial effect of miniaturization, long back focus, high image quality, infrared confocality, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Other features, objects and advantages of the present application will become more apparent by reading the detailed description of non-limiting embodiments made with reference to the following drawings. In the drawings:

[0029] Figure 1 A schematic structural diagram of a viewing and aiming lens according to Embodiment 1 of the present application is shown;

[0030] Figure 2A shows a relative illumination curve of the aiming and viewing lens according to Example 1 of the present application;

[0031] Figure 2B A Ray Fan diagram of the aiming lens according to Embodiment 1 of the present application is shown;

[0032] Figure 3 A schematic structural diagram of a sighting lens according to Embodiment 2 of the present application is shown;

[0033] Figure 4A shows a relative illumination curve of the aiming and viewing lens according to Embodiment 2 of the present application;

[0034] Figure 4B A Ray Fan diagram of the aiming lens according to Embodiment 2 of the present application is shown;

[0035] Figure 5 A schematic structural diagram of a viewing and aiming lens according to Embodiment 3 of the present application is shown;

[0036] Fig. 6A shows a relative illumination curve of the aiming and viewing lens according to Embodiment 3 of the present application;

[0037] Figure 6B A Ray Fan diagram of the aiming lens according to Embodiment 3 of the present application is shown;

[0038] Figure 7 A schematic structural diagram of a sighting lens according to Embodiment 4 of the present application is shown;

[0039] Fig. 8A shows a relative illumination curve of the aiming and viewing lens according to Embodiment 4 of the present application; and

[0040] Figure 8B A Ray Fan diagram of the aiming lens according to Example 4 of the present application is shown. DETAILED DESCRIPTION

[0041] In order to better understand the present application, various aspects of the present application are described in detail with reference to the accompanying drawings. It should be understood that these detailed descriptions are only descriptions of exemplary embodiments of the present application, and do not limit the scope of the present application in any way.

[0042] In the drawings, the thickness, size and shape of the lenses have been slightly exaggerated for ease of illustration. Specifically, the shapes of the spherical or aspherical surfaces shown in the drawings are shown by way of example. That is, the shapes of the spherical or aspherical surfaces are not limited to the shapes of the spherical or aspherical surfaces shown in the drawings. The drawings are for illustration only and are not drawn strictly to scale.

[0043] In this article, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the position of the convex surface is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the position of the concave surface is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the object is called the object side of the lens, and the surface of each lens closest to the imaging plane is called the image side of the lens.

[0044] It should also be understood that the terms "include", "comprising", "having", "including" and / or "comprising", when used in this specification, indicate the presence of the stated features, elements and / or components, but do not exclude the presence or addition of one or more other features, elements, components and / or combinations thereof. It should be noted that in this specification, the expressions first, second, third, etc. are only used to distinguish one feature from another, and do not represent any limitation on the features.

[0045] Unless otherwise defined, all terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which this application belongs. Terms should be interpreted as having the same meaning as they have in the context of the relevant technology, and will not be interpreted in an idealized or overly formal sense unless explicitly defined in this article.

[0046] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0047] The aiming lens according to an exemplary embodiment of the present application may include a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens and an eighth lens, and the eight lenses are arranged in sequence from the object side to the image plane along the optical axis.

[0048] In an exemplary embodiment, the second lens, the third lens, and the fourth lens are cemented to form a triplet lens, and the fifth lens and the sixth lens are cemented to form a doublet lens. In other examples, the second lens and the third lens are cemented to form a doublet lens. The fourth lens, the fifth lens, and the sixth lens are cemented to form a triplet lens.

[0049] In an exemplary embodiment, the first lens may have a positive refractive power. The object side surface of the first lens may be a convex surface, and the image side surface may be a concave surface or a plane surface. The first lens collects incident light. By designing the first lens as a positive lens, the first lens can converge the incident light, ensuring that the light emitted from the first lens is close to the optical axis, which is beneficial to reducing the aperture of the rear lens and realizing the miniaturization of the sighting lens. The image side surface of the first lens is designed to be a plane or a concave surface, which can reduce the incident angle of the axial light on the image side surface of the first lens, reduce the spherical aberration generated by the image side surface of the first lens, and facilitate the realization of high image quality of the sighting lens. In other examples, the first lens can be made of a high Abbe number material to reduce the generation of axial dispersion, reduce the difficulty of chromatic aberration correction of the sighting lens, and facilitate the realization of infrared confocal.

[0050] In an exemplary embodiment, the second lens may have a negative refractive power. The object side surface of the second lens may be a convex surface, and the image side surface may be a concave surface. By setting the second lens in the above-mentioned structural form, the incident angle of the axial light on the object side surface of the second lens can be reduced, and the spherical aberration generated by the object side surface of the second lens can be reduced, which is conducive to achieving high image quality of the sighting lens. In other examples, the object side surface of the second lens may be a plane, and the object side surface of the second lens generates a large negative spherical aberration, and compensates for the positive spherical aberration generated by the first lens, thereby reducing the difficulty of aberration correction of the sighting lens, which is conducive to achieving high image quality of the sighting lens.

[0051] In an exemplary embodiment, the third lens may have positive refractive power. The object side surface of the third lens may be a convex surface, and the image side surface may be a convex surface. By setting the third lens in the above-mentioned structural form, the object side surface and the image side surface of the third lens can share the refractive power, reduce the surface curvature of the object side surface and the image side surface of the third lens, reduce the generation of aberrations, and facilitate the realization of high image quality of the sighting lens. In other examples, the image side surface of the third lens may be a concave surface, reduce the incident angle of the axial light on the image side surface of the third lens, reduce the spherical aberration generated by the image side surface of the third lens, and facilitate the realization of high image quality of the sighting lens. In other examples, the third lens has positive refractive power in a triplet or doublet lens, and is made of a high Abbe number material, which can perform apochromatism on the sighting lens, and facilitates the realization of infrared confocal.

[0052] In an exemplary embodiment, the fourth lens may have a negative refractive power. The object side surface of the fourth lens may be a concave surface, and the image side surface may be a concave surface. By setting the fourth lens in the above-mentioned structural form, the object side surface and the image side surface of the fourth lens can share the refractive power, reduce the surface curvature of the object side surface and the image side surface of the fourth lens, reduce the generation of aberrations, and facilitate the realization of high image quality of the sighting lens. In other examples, the object side surface of the fourth lens may be a convex surface, reduce the incident angle of the axial light on the object side surface of the fourth lens, reduce the spherical aberration generated by the object side surface of the fourth lens, and facilitate the realization of high image quality of the sighting lens. In other examples, the fourth lens has a negative refractive power in the triplet lens, which cooperates with the third lens and the fifth lens to realize the correction of apochromatism and spherical aberration of the sighting lens, and facilitates the realization of high image quality of the sighting lens.

[0053] In an exemplary embodiment, the fifth lens may have positive refractive power. The object side surface of the fifth lens may be convex, and the image side surface may be convex. By setting the fifth lens in the above-mentioned structural form, the object side surface and the image side surface of the fifth lens can share the refractive power, reduce the surface curvature of the object side surface and the image side surface of the fifth lens, reduce the generation of aberrations, and facilitate the realization of high image quality of the sighting lens. In other examples, the fifth lens has positive refractive power in a triplet or doublet lens, and is made of a high Abbe number material, which can perform apochromatism on the sighting lens, which is conducive to achieving infrared confocal.

[0054] In an exemplary embodiment, the sixth lens may have a negative refractive power. The object side surface of the sixth lens may be a concave surface, and the image side surface may be a concave surface. By setting the sixth lens in the above-mentioned structural form, the object side surface and the image side surface of the sixth lens can share the refractive power, reduce the surface curvature of the object side surface and the image side surface of the sixth lens, reduce the generation of aberrations, and help achieve high image quality of the sighting lens. In other examples, the sixth lens has a negative refractive power in a triplet or doublet lens, which cooperates with the fifth lens to achieve correction of achromatism and spherical aberration of the sighting lens, which helps achieve high image quality of the sighting lens.

[0055] In an exemplary embodiment, the seventh lens may have a positive refractive power. Both the object side surface and the image side surface of the seventh lens may be convex. By setting the seventh lens in the above-mentioned structural form, the object side surface and the image side surface of the seventh lens can share the refractive power, reduce the surface curvature of the object side surface and the image side surface of the seventh lens, reduce the generation of aberrations, and help achieve high image quality of the viewing and aiming lens. In addition, the seventh lens is designed as a positive lens, and the axial chromatic aberration of the viewing and aiming lens can also be corrected, which is conducive to achieving high image quality of the viewing and aiming lens.

[0056] In an exemplary embodiment, the seventh lens may have a negative refractive power. The object side surface of the seventh lens may be a convex surface, and the image side surface may be a concave surface. The first to sixth lenses constitute a front lens group, and the seventh and eighth lenses constitute a rear lens group. When the seventh lens is designed as a negative lens, the refractive power of the rear lens group is negative, and it forms a telephoto architecture together with the front lens group with positive refractive power, which is conducive to reducing the total optical length of the viewing and aiming lens and realizing the miniaturization of the viewing and aiming lens.

[0057] In an exemplary embodiment, the eighth lens may have a negative refractive power. The object side surface of the eighth lens may be a concave surface, and the image side surface may be a convex surface or a concave surface. When the eighth lens is designed as a negative lens, the refractive power of the optical lens group composed of the first lens to the seventh lens is positive, and the eighth lens and the optical lens group composed of the first lens to the seventh lens with positive refractive power together form a telephoto architecture, which is conducive to reducing the total optical length of the sighting lens and realizing the miniaturization of the sighting lens. In other examples, the eighth lens is made of a high Abbe number material to improve the ability of the eighth lens to refract light, reduce the surface curvature of the object side and image side of the eighth lens, reduce the generation of aberrations, and help achieve high image quality of the sighting lens.

[0058] In an exemplary embodiment, the eighth lens may have a positive refractive power. The object side surface of the eighth lens may be a convex surface, and the image side surface may be a concave surface. The eighth lens is designed as a convex-concave meniscus positive lens, which can move the main surface of the viewing and aiming lens backward, increase the back focal length of the viewing and aiming lens, and can also compensate for the field curvature and astigmatism generated by the seventh lens, correct chromatic aberration, and is conducive to achieving high image quality of the viewing and aiming lens.

[0059] In an exemplary embodiment, the second lens and the third lens are cemented to form a doublet lens. The curvature of the object side of the second lens and the image side of the third lens are similar, and the doublet lens is in a meniscus shape with a small refractive power, which is conducive to reducing the generation of spherical aberration. The third lens is made of a high Abbe number material, which can reduce the generation of chromatic aberration and is conducive to correcting the chromatic aberration of the sighting lens. The second lens and the third lens can correct their own aberrations through the combination of materials and refractive powers, which is conducive to reducing the tolerance sensitivity of the sighting lens.

[0060] In an exemplary embodiment, the fourth lens, the fifth lens, and the sixth lens are cemented to form a triplet lens. The curvature of the object side of the fourth lens and the image side of the sixth lens are similar, and the triplet lens is in a meniscus shape with a small refractive power, which is conducive to reducing the generation of spherical aberration. The fifth lens is made of a high Abbe number material, which can reduce the generation of chromatic aberration and is conducive to correcting the chromatic aberration of the sighting lens. The fourth lens, the fifth lens, and the sixth lens can correct their own aberrations through the combination of materials and refractive powers, which is conducive to reducing the tolerance sensitivity of the sighting lens.

[0061] In an exemplary embodiment, the second lens, the third lens, and the fourth lens are cemented to form a triplet lens. The curvature of the object side of the second lens and the image side of the fourth lens are similar, and the triplet lens is in a meniscus shape with a small refractive power, which is conducive to reducing the generation of spherical aberration. The third lens is made of a high Abbe number material, which can reduce the generation of chromatic aberration and is conducive to correcting the chromatic aberration of the sighting lens. The second lens, the third lens, and the fourth lens can correct their own aberrations through the combination of materials and refractive powers, which is conducive to reducing the tolerance sensitivity of the sighting lens.

[0062] In an exemplary embodiment, the fifth lens and the sixth lens are cemented to form a doublet lens. The curvature of the object side of the fifth lens and the image side of the sixth lens are similar, and the doublet lens is in a meniscus shape with a small refractive power, which is conducive to reducing the generation of spherical aberration. The fifth lens is made of a high Abbe number material, which can reduce the generation of chromatic aberration and is conducive to correcting the chromatic aberration of the sighting lens. The fifth lens and the sixth lens can correct their own aberrations through the combination of materials and refractive powers, which is conducive to reducing the tolerance sensitivity of the sighting lens.

[0063] In example embodiments, at least one lens of the first to eighth lenses may be a spherical lens.

[0064] In an exemplary embodiment, the aiming lens further includes an aperture stop disposed between the first lens and the second lens.

[0065] In an exemplary embodiment, the maximum full aperture Dmax of the sighting lens and the total optical length TTL of the sighting lens may satisfy: 0.45≤Dmax / TTL≤0.53. Reasonable configuration of the ratio of the maximum full aperture to the total optical length of the sighting lens can make the maximum full aperture of the sighting lens smaller when the total optical length of the sighting lens is constant, which is conducive to miniaturization of the sighting lens.

[0066] In an exemplary embodiment, the total optical length TTL of the sighting lens and the total effective focal length f of the sighting lens may satisfy: 0.85≤TTL / f≤1.00. Reasonable configuration of the ratio of the total optical length to the total effective focal length of the sighting lens can reduce the total optical length of the sighting lens when the total effective focal length of the sighting lens is constant, which is conducive to miniaturization of the sighting lens.

[0067] In an exemplary embodiment, the total effective focal length f of the sighting lens and the entrance pupil diameter ENPD of the sighting lens may satisfy: 2.10≤f / ENPD≤2.30. Reasonable configuration of the ratio of the total effective focal length of the sighting lens to the entrance pupil diameter can enable the sighting lens to have a smaller aperture number, which is conducive to achieving a large aperture of the sighting lens.

[0068] In an exemplary embodiment, the back focal length BFL of the sighting and aiming lens and the total optical length TTL of the sighting and aiming lens may satisfy: 0.15≤BFL / TTL≤0.35. Reasonable configuration of the ratio of the back focal length of the sighting and aiming lens to the total optical length can constrain the back focal length of the sighting and aiming lens within a certain range on the basis of realizing the miniaturization of the sighting and aiming lens, which is beneficial to the assembly of the sighting and aiming lens.

[0069] In an exemplary embodiment, the effective focal length f1 of the first lens and the total effective focal length f of the sighting lens may satisfy: 0.55≤f1 / f≤1.20. Reasonable configuration of the effective focal length of the first lens can make the light emitted from the first lens close to the optical axis, which is conducive to reducing the aperture of the rear lens, thereby realizing the miniaturization of the sighting lens.

[0070] In an exemplary embodiment, the effective focal length f2 of the second lens and the total effective focal length f of the sighting lens may satisfy: -1.30≤f2 / f≤-0.5. Reasonable configuration of the effective focal length of the second lens can cause the second lens to generate negative spherical aberration, and the negative spherical aberration generated by the second lens can compensate for the positive spherical aberration generated by the first lens, which is conducive to achieving high image quality of the sighting lens.

[0071] In an exemplary embodiment, the effective focal length f3 of the third lens and the total effective focal length f of the sighting lens may satisfy: 0.30≤f3 / f≤1.00. Reasonable configuration of the effective focal length of the third lens can make the third lens have positive refractive power in a triplet or doublet lens, and at the same time, with low dispersion materials, the sighting lens can be apochromatic, which is conducive to achieving infrared confocal.

[0072] In an exemplary embodiment, the effective focal length f4 of the fourth lens and the total effective focal length f of the sighting lens may satisfy: -0.95≤f4 / f≤-0.45. Reasonable configuration of the effective focal length of the fourth lens can make the fourth lens have a negative refractive power in the triplet lens, which, in conjunction with the third lens and the fifth lens, can achieve correction of apochromatic aberration and spherical aberration of the sighting lens, which is conducive to achieving high image quality of the sighting lens.

[0073] In an exemplary embodiment, the effective focal length f5 of the fifth lens and the total effective focal length f of the sighting lens may satisfy: 0.25≤f5 / f≤0.65. Reasonable configuration of the effective focal length of the fifth lens can make the fifth lens have positive refractive power in a triplet or doublet lens, and at the same time, with low dispersion materials, the sighting lens can be apochromatic, which is conducive to achieving infrared confocal.

[0074] In an exemplary embodiment, the effective focal length f6 of the sixth lens and the total effective focal length f of the sighting lens may satisfy: -0.70≤f6 / f≤-0.15. Reasonable configuration of the effective focal length of the sixth lens can make the sixth lens have a negative refractive power in a triplet or doublet lens, which, in conjunction with the fifth lens, can achieve correction of apochromatism and spherical aberration of the sighting lens, which is conducive to achieving high image quality of the sighting lens.

[0075] In an exemplary embodiment, the effective focal length f7 of the seventh lens and the total effective focal length f of the sighting lens may satisfy: 0.15≤|f7 / f|≤0.60. The effective focal length of the seventh lens is reasonably configured. When the effective focal length of the seventh lens is a positive value, it is beneficial to correct the axial chromatic aberration of the sighting lens and achieve high image quality of the sighting lens; when the effective focal length of the seventh lens is a negative value, the refractive power of the rear lens group (the lens group composed of the seventh lens and the eighth lens) is negative, and it forms a telephoto structure together with the front lens group with positive refractive power (the lens group composed of the first lens to the sixth lens), which is beneficial to reduce the total optical length of the sighting lens and achieve miniaturization of the sighting lens.

[0076] In an exemplary embodiment, the effective focal length f8 of the eighth lens and the total effective focal length f of the viewing and aiming lens may satisfy: 0.20≤|f8 / f|≤0.70. The effective focal length of the eighth lens is reasonably configured. When the effective focal length of the eighth lens is a positive value, the main surface of the viewing and aiming lens moves backward, which is conducive to increasing the back focal length of the viewing and aiming lens; when the effective focal length of the eighth lens is a negative value, it forms a telephoto structure together with the optical lens group with positive refractive power and composed of the first lens to the seventh lens, which is conducive to reducing the total optical length of the viewing and aiming lens and realizing the miniaturization of the viewing and aiming lens.

[0077] In an exemplary embodiment, the effective focal length fa of the triplet lens and the total effective focal length f of the sighting lens may satisfy: 1.10≤|fa / f|≤5.10. Reasonable configuration of the effective focal length of the triplet lens can reduce the absolute value of the diopter of the triplet lens, reduce the generation of high-order aberrations, and facilitate the realization of high image quality of the sighting lens.

[0078] In an exemplary embodiment, the effective focal length fb of the double-cemented lens and the total effective focal length f of the sighting lens may satisfy: 0.50≤|fb / f|≤3.75. Reasonable configuration of the effective focal length of the double-cemented lens can reduce the absolute value of the diopter of the double-cemented lens, reduce the generation of high-order aberrations, and facilitate the realization of high image quality of the sighting lens.

[0079] In an exemplary embodiment, the combined focal length F1 of the first lens to the sixth lens and the total effective focal length f of the sighting lens may satisfy: 0.75≤|F1 / f|≤1.35. Reasonable configuration of the combined focal length of the first lens to the sixth lens can make the focal length of the front lens group composed of the first lens to the sixth lens positive, which is conducive to reducing the total optical length of the sighting lens and realizing the miniaturization of the sighting lens.

[0080] In an exemplary embodiment, the combined focal length F2 of the seventh lens and the eighth lens and the total effective focal length f of the sighting lens may satisfy: 1.10≤|F2 / f|≤9.85. Reasonable configuration of the combined focal length of the seventh lens and the eighth lens can make the focal length of the rear lens group composed of the seventh lens and the eighth lens a negative value, which is beneficial to reducing the total optical length of the sighting lens and realizing the miniaturization of the sighting lens.

[0081] In an exemplary embodiment, the combined focal length F1 of the first to sixth lenses and the combined focal length F2 of the seventh and eighth lenses may satisfy: 0.05≤|F1 / F2|≤0.85. Reasonable configuration of the ratio of the combined focal length of the first to sixth lenses to the combined focal length of the seventh and eighth lenses can make the focal length of the front lens group composed of the first to sixth lenses positive, and the focal length of the rear lens group composed of the seventh and eighth lenses negative, and the two form a telephoto structure, reducing the total optical length of the sighting lens, which is conducive to miniaturization of the sighting lens.

[0082] In an exemplary embodiment, the curvature radius R72 of the image side surface of the seventh lens and the curvature radius R81 of the object side surface of the eighth lens may satisfy: -0.35≤(R72-R81) / (R72+R81)≤0.45. Reasonable configuration of the curvature radius of the image side surface of the seventh lens and the curvature radius of the object side surface of the eighth lens can make the aberrations generated by the image side surface of the seventh lens and the object side surface of the eighth lens compensate each other, which is conducive to achieving high image quality of the sighting lens.

[0083] In an exemplary embodiment, the Abbe number VD1 of the first lens may satisfy: 65≤VD1≤100. Reasonable configuration of the Abbe number of the first lens can reduce the generation of dispersion, reduce the difficulty of chromatic aberration correction of the sighting lens, and facilitate the realization of infrared confocal.

[0084] In an exemplary embodiment, the Abbe number VD3 of the third lens may satisfy: 90≤VD3≤100. Reasonable configuration of the Abbe number of the third lens can reduce the generation of dispersion, reduce the difficulty of chromatic aberration correction of the sighting lens, and facilitate the realization of infrared confocal.

[0085] In an exemplary embodiment, the Abbe number VD5 of the fifth lens may satisfy: 65≤VD5≤100. Reasonable configuration of the Abbe number of the fifth lens can reduce the generation of dispersion, reduce the difficulty of chromatic aberration correction of the sighting lens, and facilitate the realization of infrared confocal.

[0086] The sighting lens according to the above embodiment of the present application may use multiple lenses, such as the eight lenses mentioned above, and by reasonably allocating the optical parameters such as the refractive power, surface shape, center thickness of each lens, and the on-axis spacing between each lens, it is possible to achieve at least one of miniaturization, long back focus, high image quality, and infrared confocality of the sighting lens. The sighting lens provided in the present application may be, for example, 4K high image quality.

[0087] Those skilled in the art should understand that the total optical length TTL of the viewing and aiming lens used above refers to the on-axis distance from the object side of the first lens to the imaging plane; the back focal length BFL of the viewing and aiming lens refers to the on-axis distance from the image side of the eighth lens to the imaging plane.

[0088] However, those skilled in the art should understand that, without departing from the technical solution claimed in the present application, the number of lenses constituting the aiming lens can be changed to obtain the various results and advantages described in this specification.

[0089] Specific embodiments of the aiming lens applicable to the above-mentioned embodiments will be further described below with reference to the accompanying drawings.

[0090] Example 1

[0091] The following reference Figures 1 to 2B The aiming lens according to Embodiment 1 of the present application is described. Figure 1 Schematic diagram of the structure of the aiming and viewing lens according to Embodiment 1 of the present application.

[0092] like Figure 1 As shown, the aiming lens 100 includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7 and an eighth lens L8 in order from the object side to the image plane along the optical axis. The aperture STO is disposed between the first lens L1 and the second lens L2. The second lens L2, the third lens L3 and the fourth lens L4 are cemented to form a triplet lens, and the fifth lens L5 and the sixth lens L6 are cemented to form a doublet lens.

[0093] The first lens L1 has positive refractive power, an object-side surface S1 of which is convex, and an image-side surface S2 of which is flat.

[0094] The second lens L2 has negative refractive power, and its object-side surface S3 is convex and its image-side surface is concave.

[0095] The third lens L3 has positive refractive power, and its object-side surface S4 is convex and its image-side surface is convex.

[0096] The fourth lens L4 has negative refractive power, and its object-side surface S5 is concave, and its image-side surface S6 is concave.

[0097] The fifth lens L5 has positive refractive power, and its object-side surface S7 is convex and its image-side surface is convex.

[0098] The sixth lens L6 has negative refractive power, and its object-side surface S8 is concave, and its image-side surface S9 is concave.

[0099] The seventh lens L7 has positive refractive power, and its object-side surface S10 is convex, and its image-side surface S11 is convex.

[0100] The eighth lens L8 has negative refractive power, and its object-side surface S12 is concave, and its image-side surface S13 is convex.

[0101] A filter CG may also be provided between the eighth lens L8 and the imaging surface IMA. The filter CG has an object side surface S14 and an image side surface S15. Light from the object passes through each surface S1 to S15 in sequence and is finally imaged on the imaging surface IMA. It should be noted that the surfaces S1 to S15 are Figure 1 Not shown.

[0102] Table 1 shows the basic parameters of the sighting lens 100 of Example 1, wherein the units of the curvature radius, thickness / distance and focal length are all in millimeters (mm). The total effective focal length f of the sighting lens is 60 mm.

[0103]

[0104]

[0105] Table 1

[0106] Figure 2A FIG. 1 shows a relative illumination curve of the aiming lens 100 , which indicates relative illumination corresponding to different fields of view. Figure 2B FIG. 1 shows a Ray Fan diagram of the aiming lens 100. Figure 2A and Figure 2B It can be seen that the viewing and aiming lens 100 provided in Example 1 can achieve good imaging quality.

[0107] Example 2

[0108] The following reference Figures 3 to 4B The aiming lens according to Embodiment 2 of the present application is described. Figure 3 Schematic diagram of the structure of the aiming and viewing lens according to Embodiment 2 of the present application.

[0109] like Figure 3 As shown, the aiming lens 200 includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7 and an eighth lens L8 in order from the object side to the image plane along the optical axis. The aperture STO is disposed between the first lens L1 and the second lens L2. The second lens L2, the third lens L3 and the fourth lens L4 are cemented to form a triplet lens, and the fifth lens L5 and the sixth lens L6 are cemented to form a doublet lens.

[0110] The first lens L1 has positive refractive power, an object-side surface S1 of which is convex, and an image-side surface S2 of which is concave.

[0111] The second lens L2 has negative refractive power, and its object-side surface S3 is convex and its image-side surface is concave.

[0112] The third lens L3 has positive refractive power, and its object-side surface S4 is convex and its image-side surface is convex.

[0113] The fourth lens L4 has negative refractive power, and its object-side surface S5 is concave, and its image-side surface S6 is concave.

[0114] The fifth lens L5 has positive refractive power, and its object-side surface S7 is convex and its image-side surface is convex.

[0115] The sixth lens L6 has negative refractive power, and its object-side surface S8 is concave, and its image-side surface S9 is concave.

[0116] The seventh lens L7 has positive refractive power, and its object-side surface S10 is convex, and its image-side surface S11 is convex.

[0117] The eighth lens L8 has negative refractive power, and its object-side surface S12 is concave, and its image-side surface S13 is concave.

[0118] A filter CG may also be provided between the eighth lens L8 and the imaging surface IMA. The filter CG has an object side surface S14 and an image side surface S15. Light from the object passes through each surface S1 to S15 in sequence and is finally imaged on the imaging surface IMA. It should be noted that the surfaces S1 to S15 are Figure 3 Not shown.

[0119] Table 2 shows the basic parameters of the sighting lens 200 of Example 2, wherein the units of the curvature radius, thickness / distance and focal length are all in millimeters (mm). The total effective focal length f of the sighting lens is 60 mm.

[0120]

[0121] Table 2

[0122] Figure 4AThe relative illumination curve of the aiming lens 200 is shown, which indicates the relative illumination corresponding to different fields of view. Figure 4B FIG. 2 shows a Ray Fan diagram of the aiming lens 200. Figure 4A and Figure 4B It can be seen that the viewing and aiming lens 200 provided in Example 2 can achieve good imaging quality.

[0123] Example 3

[0124] The following reference Figures 5 to 6B The aiming lens according to Embodiment 3 of the present application is described. Figure 5 Schematic diagram of the structure of the aiming and viewing lens according to Embodiment 3 of the present application.

[0125] like Figure 5 As shown, the aiming lens 300 includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7 and an eighth lens L8 in order from the object side to the image plane along the optical axis. The aperture STO is located between the first lens L1 and the second lens L2. The second lens L2 and the third lens L3 are cemented to form a doublet lens, and the fourth lens L4, the fifth lens L5 and the sixth lens L6 are cemented to form a triplet lens.

[0126] The first lens L1 has positive refractive power, an object-side surface S1 of which is convex, and an image-side surface S2 of which is flat.

[0127] The second lens L2 has negative refractive power, and its object-side surface S3 is a flat surface and its image-side surface is a concave surface.

[0128] The third lens L3 has positive refractive power, an object-side surface S4 thereof is convex, and an image-side surface S5 thereof is concave.

[0129] The fourth lens L4 has negative refractive power, and its object-side surface S6 is convex and its image-side surface is concave.

[0130] The fifth lens L5 has positive refractive power, and its object-side surface S7 is convex and its image-side surface is convex.

[0131] The sixth lens L6 has negative refractive power, and its object-side surface S8 is concave, and its image-side surface S9 is concave.

[0132] The seventh lens L7 has negative refractive power, and its object-side surface S10 is convex, and its image-side surface S11 is concave.

[0133] The eighth lens L8 has positive refractive power, and its object-side surface S12 is convex, and its image-side surface S13 is concave.

[0134] A filter CG may also be provided between the eighth lens L8 and the imaging surface IMA. The filter CG has an object side surface S14 and an image side surface S15. Light from the object passes through each surface S1 to S15 in sequence and is finally imaged on the imaging surface IMA. It should be noted that the surfaces S1 to S15 are Figure 5 Not shown.

[0135] Table 3 shows the basic parameters of the sighting lens 300 of Example 3, wherein the units of the curvature radius, thickness / distance and focal length are all in millimeters (mm). The total effective focal length f of the sighting lens is 60 mm.

[0136]

[0137] Table 3

[0138] Fig. 6A The relative illumination curve of the aiming lens 300 is shown, which indicates the relative illumination corresponding to different fields of view. Figure 6B FIG. 3 shows a Ray Fan diagram of the aiming lens 300. Fig. 6A and Figure 6B It can be seen that the viewing and aiming lens 300 provided in Example 3 can achieve good imaging quality.

[0139] Example 4

[0140] The following reference Figures 7 to 8B The aiming lens according to Embodiment 4 of the present application is described. Figure 7 Schematic diagram of the structure of the aiming and viewing lens according to Example 4 of the present application.

[0141] like Figure 7 As shown, the aiming lens 400 includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, a sixth lens L6, a seventh lens L7 and an eighth lens L8 in order from the object side to the image plane along the optical axis. The aperture STO is located between the first lens L1 and the second lens L2. The second lens L2 and the third lens L3 are cemented to form a doublet lens, and the fourth lens L4, the fifth lens L5 and the sixth lens L6 are cemented to form a triplet lens.

[0142] The first lens L1 has positive refractive power, an object-side surface S1 of which is convex, and an image-side surface S2 of which is concave.

[0143] The second lens L2 has negative refractive power, and its object-side surface S3 is convex and its image-side surface is concave.

[0144] The third lens L3 has positive refractive power, an object-side surface S4 thereof is convex, and an image-side surface S5 thereof is concave.

[0145] The fourth lens L4 has negative refractive power, and its object-side surface S6 is convex and its image-side surface is concave.

[0146] The fifth lens L5 has positive refractive power, and its object-side surface S7 is convex and its image-side surface is convex.

[0147] The sixth lens L6 has negative refractive power, and its object-side surface S8 is concave, and its image-side surface S9 is concave.

[0148] The seventh lens L7 has negative refractive power, and its object-side surface S10 is convex, and its image-side surface S11 is concave.

[0149] The eighth lens L8 has positive refractive power, and its object-side surface S12 is convex, and its image-side surface S13 is concave.

[0150] A filter CG may also be provided between the eighth lens L8 and the imaging surface IMA. The filter CG has an object side surface S14 and an image side surface S15. Light from the object passes through each surface S1 to S15 in sequence and is finally imaged on the imaging surface IMA. It should be noted that the surfaces S1 to S15 are Figure 7 Not shown.

[0151] Table 4 shows the basic parameters of the sighting lens 400 of Example 4, wherein the units of the curvature radius, thickness / distance and focal length are all in millimeters (mm). The total effective focal length f of the sighting lens is 60 mm.

[0152]

[0153] Table 4

[0154] Fig. 8A A relative illumination curve of the aiming lens 400 is shown, which indicates the relative illumination corresponding to different fields of view. Figure 8B FIG. 4 shows a Ray Fan diagram of the aiming lens 400. Fig. 8A and Figure 8B It can be seen that the viewing and aiming lens 400 provided in Example 4 can achieve good imaging quality.

[0155] In summary, the conditional expressions in Examples 1 to 4 satisfy the relationship shown in Table 5.

[0156]

[0157]

[0158] Table 5

[0159] The present application also provides an imaging device, whose electronic photosensitive element may be a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS), and the imaging device is equipped with the above-described viewing lens.

[0160] The above description is only a preferred embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the utility model involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the inventive concept. For example, the above features are replaced with the technical features with similar functions disclosed in the present application (but not limited to) by each other.

Claims

1. A sighting lens, characterized in that: Along the optical axis from the object side to the image plane, they include: The first lens has positive refractive power and its object side surface is convex; The second lens has a negative refractive power and its image side surface is concave; The third lens has positive refractive power and its object side surface is convex; The fourth lens has negative refractive power and its image side surface is concave; The fifth lens has positive refractive power, and both the object side surface and the image side surface are convex; The sixth lens has a negative refractive power, and both the object side surface and the image side surface thereof are concave; a seventh lens having a refractive power; and an eighth lens having a refractive power; The effective focal length f7 of the seventh lens and the total effective focal length f of the aiming and viewing lens satisfy: 0.15≤|f7 / f|<0.

60.

2. The sighting lens according to claim 1, characterized in that: The seventh lens has positive refractive power, and both the object side surface and the image side surface of the seventh lens are convex surfaces; or, the seventh lens has negative refractive power, the object side surface of the seventh lens is convex, and the image side surface of the seventh lens is concave.

3. The sighting lens according to claim 1, characterized in that: The eighth lens has positive refractive power, the object side surface of the eighth lens is convex, and the image side surface of the eighth lens is concave; or, the eighth lens has negative refractive power, and the object side surface of the eighth lens is concave.

4. The sighting lens according to claim 1, characterized in that: The total optical length TTL of the sighting lens and the total effective focal length f of the sighting lens satisfy: 0.85 <TTL / f≤1.00。 5. The sighting lens according to claim 1, characterized in that: Three adjacent lenses among the second lens to the sixth lens are glued together to form a triplet lens, and the effective focal length fa of the triplet lens and the total effective focal length f of the aiming lens satisfy: 1.10≤|fa / f|≤5.

10.

6. The sighting lens according to claim 1, characterized in that: Two adjacent lenses among the second lens to the sixth lens are glued together to form a doublet lens, and the effective focal length fb of the doublet lens and the total effective focal length f of the aiming lens satisfy the following: 0.50<|fb / f|≤3.

75.

7. The sighting lens according to claim 1, characterized in that: The combined focal length F1 of the first lens to the sixth lens and the total effective focal length f of the aiming lens satisfy the following: 0.75<|F1 / f|<1.

35.

8. The sighting lens according to claim 1, characterized in that: The combined focal length F2 of the seventh lens and the eighth lens and the total effective focal length f of the aiming lens satisfy the following: 1.10≤|F2 / f|≤9.

85.

9. The sighting lens according to claim 1, characterized in that: A combined focal length F1 of the first to sixth lenses and a combined focal length F2 of the seventh lens and the eighth lens satisfy the following: 0.05<|F1 / F2|≤0.

85.

10. The sighting lens according to claim 1, characterized in that: The sighting lens satisfies one of the following conditions: 0.45≤Dmax / TTL≤0.53; 2.10≤f / ENPD≤2.30; 0.15≤BFL / TTL≤0.35; 0.55≤f1 / f≤1.20; -1.30≤f2 / f≤-0.50; 0.30≤f3 / f≤1.00; -0.95≤f4 / f≤-0. 45;0.25≤f5 / f≤0.65;-0.70≤f6 / f≤-0.15;0.20≤|f8 / f|<0.70;-0.35≤ (R72-R81) / (R72+R81)≤0.45; 65≤VD1≤100; 90≤VD3≤100; 65≤VD5≤100; Wherein, Dmax is the maximum clear aperture of the aiming and viewing lens, TTL is the total optical length of the aiming and viewing lens, f is the total effective focal length of the aiming and viewing lens, ENPD is the entrance pupil diameter of the aiming and viewing lens, BFL is the back focal length of the aiming and viewing lens, f1 is the effective focal length of the first lens, f2 is the effective focal length of the second lens, f3 is the effective focal length of the third lens, f4 is the effective focal length of the fourth lens, f5 is the effective focal length of the fifth lens, f6 is the effective focal length of the sixth lens, f8 is the effective focal length of the eighth lens, R72 is the curvature radius of the image side surface of the seventh lens, R81 is the curvature radius of the object side surface of the eighth lens, VD1 is the Abbe number of the first lens, VD3 is the Abbe number of the third lens, and VD5 is the Abbe number of the fifth lens.

Images