Imaging lens

Abstract

The utility model discloses an imaging lens, which comprises an imaging lens group, a prism and an image plane, and is characterized in that the imaging lens group and the image plane are located on the same side of the prism; wherein the imaging lens group sequentially comprises a first lens, a second lens, a third lens and a fourth lens from an object side to an image side along a first optical axis; the first lens has positive focal power, and the object side surface of the first lens is a convex surface; the second lens has positive focal power, and the object side surface of the second lens is a convex surface; the third lens has negative focal power, the object side surface of the third lens is a concave surface, and the image side surface is a convex surface; the fourth lens has negative focal power, the object side surface of the fourth lens is a convex surface, and the image side surface is a concave surface; the prism has a first surface and a second surface which are parallel to each other; the number of the lenses with the focal power of the imaging lens is four; the total effective focal length f of the imaging lens, the aperture a of the first surface of the prism, the aperture b of the second surface of the prism and the distance c between the first surface and the second surface of the prism meet the following conditions: 52.7 mmlt; f * ((b-a) / 2 / c) lt; and the thickness of the aluminum alloy is 65.15 mm.

Description

Technical Field

[0001] The present application relates to the field of optical devices, and particularly to an imaging lens. Background Art

[0002] With the rapid development of portable devices such as smart phones, telephoto lenses have been widely used due to their advantages of clearly imaging distant objects, having a large magnification ratio, and being able to present the detailed features of objects.

[0003] The total effective focal length of an imaging lens is an important criterion for measuring whether the imaging lens is a telephoto lens. The larger the total effective focal length of the imaging lens, the clearer the distant objects photographed by the imaging lens. The total effective focal length of the imaging lens is proportional to the optical path required by the imaging lens, that is, the larger the total effective focal length of the imaging lens, the greater the optical path required by the imaging lens. Therefore, in order to achieve the telephoto characteristics of the imaging lens, the overall length of the existing imaging lens is usually large, which will limit the application of the imaging lens in portable devices. Summary of the Utility Model

[0004] The present application provides an imaging lens that can at least solve or partially solve at least one problem or other problems existing in the prior art.

[0005] One aspect of the present application provides such an imaging lens, which includes an imaging lens group, a prism, and an image plane. The imaging lens group and the image plane are located on the same side of the prism. The imaging lens group sequentially includes a first lens, a second lens, a third lens, and a fourth lens along the first optical axis from the object side to the image side. The first lens has a positive optical power, and its object side surface is convex. The second lens has a positive optical power, and its object side surface is convex. The third lens has a negative optical power, its object side surface is concave, and its image side surface is convex. The fourth lens has a negative optical power, its object side surface is convex, and its image side surface is concave. The prism has a first surface and a second surface that are parallel to each other. The number of lenses with optical power in the imaging lens is four. The total effective focal length f of the imaging lens, the aperture a of the first surface of the prism, the aperture b of the second surface of the prism, and the distance c between the first surface and the second surface of the prism satisfy: 52.7mm < f×((b - a) / 2 / c) < 65.15mm.

[0006] According to an exemplary embodiment of the present application, the sum ∑CT of the central thicknesses of all the lenses among the first lens to the fourth lens on the first optical axis, the aperture b of the second surface of the prism, and the distance c between the first surface and the second surface of the prism satisfy: 0.25 < (∑CT + c) / b < 0.3.

[0007] According to an exemplary embodiment of the present application, the effective focal length f1 of the first lens, the refractive index N1 of the first lens, and the curvature radius R1 of the object side surface of the first lens satisfy: 2.3 ≤ f1×N1 / R1 < 4.8.

[0008] According to an exemplary embodiment of the present application, the total effective focal length f of the imaging lens and the radius of curvature R5 of the object side surface of the third lens satisfy: -7.9 < f / R5 < -7.1.

[0009] According to an exemplary embodiment of the present application, the central thickness CT2 of the second lens on the first optical axis, the central thickness CT3 of the third lens on the first optical axis, and the spacing distance T23 between the second lens and the third lens on the first optical axis satisfy: 1.4 < (CT2 + CT3) / T23 < 3.3.

[0010] According to an exemplary embodiment of the present application, the effective focal length f1 of the first lens, the Abbe number V1 of the first lens, the effective focal length f3 of the third lens, and the Abbe number V3 of the third lens satisfy: 1.6mm -1 < (V1 + V3) / (f1 - f3) < 2.05mm -1 .

[0011] According to an exemplary embodiment of the present application, the axial distance SAG11 between the intersection point of the object side surface of the first lens and the first optical axis and the vertex of the effective semi-aperture of the object side surface of the first lens and the axial distance SAG21 between the intersection point of the object side surface of the second lens and the first optical axis and the vertex of the effective semi-aperture of the object side surface of the second lens satisfy: 0.65 < SAG21 / SAG11 < 2.1.

[0012] According to an exemplary embodiment of the present application, the combined focal length f12 of the first lens and the second lens and the spacing distance T12 between the first lens and the second lens on the first optical axis satisfy: 100.8 < f12 / T12 < 110.4.

[0013] According to an exemplary embodiment of the present application, the effective focal length f3 of the third lens, the refractive index N3 of the third lens, and the central thickness CT3 of the third lens on the first optical axis satisfy: -79.8 < f3×N3 / CT3 < -43.95.

[0014] According to an exemplary embodiment of the present application, the effective focal length f2 of the second lens and the radius of curvature R3 of the object side surface of the second lens satisfy: 1.1 < f2 / R3 ≤ 2.9.

[0015] According to an exemplary embodiment of the present application, the central thickness CT2 of the second lens on the first optical axis and the central thickness CT4 of the fourth lens on the first optical axis satisfy: 2.5 < CT2 / CT4 < 3.55.

[0016] According to an exemplary embodiment of the present application, the effective focal length f4 of the fourth lens and the combined focal length f123 of the first, second, and third lenses satisfy: -1.6 < f4 / f123 ≤ -1.2.

[0017] According to an exemplary embodiment of the present application, the radius of curvature R6 of the image side of the third lens and the radius of curvature R7 of the object side of the fourth lens satisfy: -1.55 < R6 / R7 < -1.35.

[0018] According to an exemplary embodiment of the present application, the positions of the fourth lens and the prism are fixed relative to the image plane, and the distance of the lens group formed by the first, second, and third lenses is adjustable relative to the fourth lens on the first optical axis. The total effective focal length f of the imaging lens satisfies: 31.95 mm < f ≤ 34.0 mm.

[0019] According to an exemplary embodiment of the present application, the on-axis distance from the image side of the fourth lens to the first surface of the prism is greater than the on-axis distance from the image side of the fourth lens to the second surface of the prism.

[0020] The first lens and the second lens of the present application have positive optical powers, and the object sides of both are convex, which can converge light rays, reduce the aperture of the rear lens, and thus reduce the longitudinal height of the entire imaging lens; the third lens and the fourth lens have negative optical powers, and the third lens is concave-convex, and the fourth lens is convex-concave, which is beneficial to reducing chromatic aberration and improving the imaging quality of the imaging lens. At the same time, by reasonably configuring the relationship between the total effective focal length of the imaging lens, the aperture of the first surface of the prism, the aperture of the second surface of the prism, and the distance between the first surface and the second surface of the prism, the prism can have an appropriate size to ensure that the light rays are reflected multiple times inside the prism, so as to achieve the long focal length characteristic of the imaging lens while meeting the miniaturization of the imaging lens. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Other features, objects, and advantages of the present application will become more apparent by reading the detailed description of the non-limiting embodiments with reference to the following drawings. Among them:

[0022] Figure 1 shows the optical path diagram of the imaging lens according to the present application;

[0023] Figure 2 shows the structural schematic diagram of the prism according to the present application;

[0024] Figure 3 shows the structural schematic diagram of the imaging lens according to Embodiment 1 of the present application;

[0025] Figures 4A to 4DThe axial chromatic aberration curve, astigmatism curve, distortion curve, and longitudinal chromatic aberration curve of the imaging lens according to Embodiment 1 of the present application in the first state are respectively shown;

[0026] Figures 5A to 5D The axial chromatic aberration curve, astigmatism curve, distortion curve, and longitudinal chromatic aberration curve of the imaging lens according to Embodiment 1 of the present application in the second state are respectively shown;

[0027] Figure 6 The schematic structural diagram of the imaging lens according to Embodiment 2 of the present application is shown;

[0028] Figures 7A to 7D The axial chromatic aberration curve, astigmatism curve, distortion curve, and longitudinal chromatic aberration curve of the imaging lens according to Embodiment 2 of the present application in the first state are respectively shown;

[0029] Figures 8A to 8D The axial chromatic aberration curve, astigmatism curve, distortion curve, and longitudinal chromatic aberration curve of the imaging lens according to Embodiment 2 of the present application in the second state are respectively shown;

[0030] Figure 9 The schematic structural diagram of the imaging lens according to Embodiment 3 of the present application is shown;

[0031] Figures 10A to 10D The axial chromatic aberration curve, astigmatism curve, distortion curve, and longitudinal chromatic aberration curve of the imaging lens according to Embodiment 3 of the present application in the first state are respectively shown;

[0032] Figures 11A to 11D The axial chromatic aberration curve, astigmatism curve, distortion curve, and longitudinal chromatic aberration curve of the imaging lens according to Embodiment 3 of the present application in the second state are respectively shown;

[0033] Figure 12 The schematic structural diagram of the imaging lens according to Embodiment 4 of the present application is shown;

[0034] Figures 13A to 13D The axial chromatic aberration curve, astigmatism curve, distortion curve, and longitudinal chromatic aberration curve of the imaging lens according to Embodiment 4 of the present application in the first state are respectively shown;

[0035] Figures 14A to 14D The axial chromatic aberration curve, astigmatism curve, distortion curve, and longitudinal chromatic aberration curve of the imaging lens according to Embodiment 4 of the present application in the second state are respectively shown;

[0036] Figure 15 The schematic structural diagram of the imaging lens according to Embodiment 5 of the present application is shown;

[0037] Figures 16A to 16D The axial chromatic aberration curve, astigmatism curve, distortion curve, and longitudinal chromatic aberration curve of the imaging lens according to Embodiment 5 of the present application in the first state are respectively shown; and

[0038] Figures 17A to 17D They respectively show the axial chromatic aberration curve, astigmatism curve, distortion curve and lateral chromatic aberration curve of the imaging lens according to Embodiment 5 of the present application in the second state. Detailed implementation manners

[0039] To better understand the present application, more detailed descriptions of various aspects of the present application will be made 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. Throughout the specification, the same reference numerals refer to the same elements.

[0040] It should be noted that in this specification, the expressions such as first, second, third, etc. are only used to distinguish one feature from another feature and do not represent any limitation on the features. Therefore, without departing from the teachings of the present application, the first lens discussed below may also be referred to as the second lens or the third lens.

[0041] In the drawings, for the sake of convenience of illustration, the thickness, size and shape of the lenses have been slightly exaggerated. Specifically, the spherical or aspherical shapes shown in the drawings are shown by way of example. That is, the spherical or aspherical shapes are not limited to the spherical or aspherical shapes shown in the drawings. The drawings are only examples and are not drawn strictly to scale.

[0042] 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 to be photographed is called the object side surface of the lens, and the surface of each lens closest to the image plane is called the image side surface of the lens.

[0043] It should also be understood that the terms "comprising" and / or "having", 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. In addition, when describing the embodiments of the present application, the use of "may" means "one or more embodiments of the present application". And the term "exemplary" is intended to refer to an example or illustration.

[0044] Unless otherwise defined, all terms (including technical terms and scientific terms) used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present application belongs. It should also be understood that terms (such as those defined in a common dictionary) should be interpreted as having a meaning consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless clearly defined herein.

[0045] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments 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.

[0046] Referring to Figure 1 , a first aspect of the present application provides such an imaging lens, which may include an imaging lens group, a prism, and an image plane. The imaging lens group and the image plane may be located on the same side of the prism and are spaced apart from each other.

[0047] In an exemplary embodiment, the imaging lens group may sequentially include a first lens, a second lens, a third lens, and a fourth lens from the object side to the image side along a first optical axis. Among the first lens to the fourth lens, there may be a spacing distance between any two adjacent lenses, and the spacing distance may be, for example, an air gap. The number of lenses having a focal power in the imaging lens may be four.

[0048] In an exemplary embodiment, the first lens may have a positive focal power, and its object side surface may be a convex surface. By configuring the first lens into the above structure, the light can be converged, the aperture of the rear lens (for example, the second lens) can be reduced, and thus the longitudinal height of the entire imaging lens can be reduced. The longitudinal height may be the height in a direction perpendicular to the lens arrangement direction of the first lens to the fourth lens.

[0049] In an exemplary embodiment, the second lens may have a positive focal power, and its object side surface may be a convex surface. By configuring the second lens into the above structure, the light can be further converged, the aperture of the rear lens (for example, the third lens) can be reduced, and thus the longitudinal height of the entire imaging lens can be reduced. The longitudinal height may be the height in a direction perpendicular to the lens arrangement direction of the first lens to the fourth lens.

[0050] In an exemplary embodiment, the third lens may have a negative focal power, its object side surface may be a concave surface, and its image side surface may be a convex surface. By configuring the third lens into the above structure, it is beneficial to reduce chromatic aberration and improve the imaging quality of the imaging lens.

[0051] In an exemplary embodiment, the fourth lens may have a negative focal power, its object side surface may be a convex surface, and its image side surface may be a concave surface. By configuring the fourth lens into the above structure, it is beneficial to reduce chromatic aberration and improve the imaging quality of the imaging lens.

[0052] In an exemplary embodiment, the first lens may be a glass lens.

[0053] In an exemplary embodiment, the third lens may be a plastic lens.

[0054] In an exemplary embodiment, referring to Figure 1 and Figure 2, the prism may have a first surface 101 and a second surface 102 that are parallel to each other. In one example, the prism may further include at least one reflective surface (e.g., 103 or 104), and at least one reflective surface (e.g., 103 or 104) may be used to connect the first surface 101 and the second surface 102.

[0055] In an exemplary embodiment, referring to Figure 1 and Figure 2 , the imaging lens group and the image plane may be located on a side of the prism away from its first surface 101, and are spaced apart from each other.

[0056] In an exemplary embodiment, the second surface 102 of the prism may include an incident area and an exit area that are spaced apart.

[0057] In an exemplary embodiment, the on-axis distance from the image side surface of the fourth lens to the first surface 101 of the prism may be greater than the on-axis distance from the image side surface of the fourth lens to the second surface 102 of the prism.

[0058] In an exemplary embodiment, the light rays exiting from the fourth lens may enter the prism through the incident area of the second surface of the prism along the first optical axis, and undergo multiple reflections inside the prism. The light rays after multiple reflections then exit along the second optical axis through the exit area of the second surface of the prism. The number of reflections of the light rays inside the prism is related to the aperture sizes of the first surface and the second surface of the prism and the distance between the first surface and the second surface of the prism.

[0059] In an exemplary embodiment, the prism may be a trapezoidal prism. Referring to Figure 1 and Figure 2 , the prism may have a first surface 101 and a second surface 102 that are parallel to each other, and a first reflective surface 103 and a second reflective surface 104 that connect the first surface 101 and the second surface 102. The aperture of the first surface 101 of the prism may be smaller than the aperture of the second surface 102 of the prism.

[0060] In an exemplary embodiment, referring to Figure 1 and Figure 2 , the light rays exiting from the fourth lens may enter the prism through the second surface 102 of the prism along the first optical axis, and be totally reflected by the first reflective surface 103 of the prism and turned towards the second surface 102, and then alternately be totally reflected by the second surface 102 and the first surface 101 and transmitted to the second reflective surface 104 of the prism, and finally be totally reflected by the second reflective surface 104 of the prism and turned towards the second surface 102 of the prism and exit along the second optical axis through the second surface 102 of the prism.

[0061] In an exemplary embodiment, referring to Figure 1 and Figure 2, the light rays exiting from the fourth lens can enter the prism along the first optical axis through the second surface 102 of the prism, and are first totally reflected by the first reflecting surface 103 of the prism to turn towards the second surface 102, then are second totally reflected by the second surface 102 to turn towards the first surface 101, are third totally reflected by the first surface 101 to turn towards the second surface 102, are fourth totally reflected by the second surface 102 to turn towards the second reflecting surface 104 of the prism, and finally are fifth totally reflected by the second reflecting surface 104 of the prism to turn towards the second surface 102 of the prism, and exit along the second optical axis through the second surface 102 of the prism.

[0062] It should be understood that the number of reflections of the light rays inside the prism being five is only exemplary, and the number of reflections of the light rays inside the prism can also be six or seven, etc., and the present application does not make specific limitations thereto.

[0063] In an exemplary embodiment, the imaging lens may further include a diaphragm. The diaphragm may be disposed between the object side and the first lens.

[0064] In an exemplary embodiment, the positions of the fourth lens and the prism relative to the image plane are fixed. The lens group formed by the first lens, the second lens, and the third lens can move relative to the fourth lens along the first optical axis, that is, the distance of the lens group formed by the first lens, the second lens, and the third lens relative to the fourth lens on the first optical axis is adjustable. When the distance between the object to be photographed and the imaging lens changes from far to near, by moving the lens group formed by the first lens, the second lens, and the third lens, the imaging lens can be switched between a first state and a second state to achieve focus adjustment of the imaging lens.

[0065] In an exemplary embodiment, the total effective focal length f of the imaging lens may satisfy: 31.95 mm < f ≤ 34.0 mm.

[0066] In an exemplary embodiment, the total effective focal length f of the imaging lens, the aperture a of the first surface of the prism, the aperture b of the second surface of the prism, and the distance c between the first surface and the second surface of the prism may satisfy: 52.7 mm < f × ((b - a) / 2 / c) < 65.15 mm. Reasonably configuring the relationship between the total effective focal length of the imaging lens, the apertures of the first surface and the second surface of the prism, and the distance between the first surface and the second surface of the prism can make the prism have an appropriate size, ensure that the light rays are reflected multiple times inside the prism, and thus achieve the characteristics of long focal length of the imaging lens while meeting the miniaturization of the imaging lens.

[0067] In an exemplary embodiment, the sum ∑CT of the central thicknesses of all the first lens to the fourth lens on the first optical axis, the aperture b of the second surface of the prism, and the distance c between the first surface and the second surface of the prism may satisfy: 0.25 < (∑CT + c) / b < 0.3. By reasonably configuring the relationship among the sum of the central thicknesses of all the first lens to the fourth lens on the first optical axis, the aperture of the second surface of the prism, and the distance between the first surface and the second surface of the prism, while the imaging lens achieves a long focal length, the distance between the first surface and the second surface of the prism can be made smaller, thereby reducing the length of the imaging lens and facilitating the miniaturization of the imaging lens.

[0068] In an exemplary embodiment, the effective focal length f1 of the first lens, the refractive index N1 of the first lens, and the curvature radius R1 of the object side surface of the first lens may satisfy: 2.3 ≤ f1×N1 / R1 < 4.8. The first lens is a glass lens, which has good temperature drift performance. By reasonably configuring the relationship among the effective focal length of the first lens, the refractive index of the first lens, and the curvature radius of the object side surface of the first lens, the imaging lens can achieve good imaging quality and ensure the processability of the first lens.

[0069] In an exemplary embodiment, the total effective focal length f of the imaging lens and the curvature radius R5 of the object side surface of the third lens may satisfy: -7.9 < f / R5 < -7.1. By controlling the ratio of the total effective focal length of the imaging lens to the curvature radius of the object side surface of the third lens, the effective focal length of the third lens can be reasonably allocated, reducing the off-axis aberration of the imaging lens and improving the image quality of the imaging lens.

[0070] In an exemplary embodiment, the central thickness CT2 of the second lens on the first optical axis, the central thickness CT3 of the third lens on the first optical axis, and the spacing distance T23 between the second lens and the third lens on the first optical axis may satisfy: 1.4 < (CT2 + CT3) / T23 < 3.3. By controlling the ratio of the sum of the central thicknesses of the second lens and the third lens to the spacing distance between the second lens and the third lens on the first optical axis, the central thicknesses of the second lens and the third lens can be constrained within a reasonable range, thereby reducing the length of the imaging lens and facilitating the miniaturization of the imaging lens.

[0071] In an exemplary embodiment, the effective focal length f1 of the first lens, the Abbe number V1 of the first lens, the effective focal length f3 of the third lens, and the Abbe number V3 of the third lens may satisfy: 1.6mm -1 < (V1 + V3) / (f1 - f3) < 2.05mm -1. The first lens is a glass lens, and the third lens is a plastic lens. By controlling the ratio of the sum of the Abbe numbers of the first lens and the third lens to the difference in the effective focal lengths of the first lens and the third lens, the axial chromatic aberration of the imaging lens can be reduced, and the aberration generated by other lenses can be balanced, improving the image quality of the imaging lens.

[0072] In an exemplary embodiment, the axial distance SAG11 between the intersection of the object side surface of the first lens and the first optical axis and the vertex of the effective semi-aperture of the object side surface of the first lens and the axial distance SAG21 between the intersection of the object side surface of the second lens and the first optical axis and the vertex of the effective semi-aperture of the object side surface of the second lens may satisfy: 0.65 < SAG21 / SAG11 < 2.1. By controlling the above conditional expression, the apertures of the first lens and the second lens can be restricted. When the imaging lens has a large aperture, the first lens and the second lens have a smaller outer diameter, and it is ensured that the first lens and the second lens have a smaller degree of curvature, thereby reserving a larger space for module installation while ensuring the formability of the first lens and the second lens.

[0073] In an exemplary embodiment, the combined focal length f12 of the first lens and the second lens and the spacing distance T12 of the first lens and the second lens on the first optical axis may satisfy: 100.8 < f12 / T12 < 110.4. By reasonably configuring the ratio of the combined focal length of the first lens and the second lens to the spacing distance of the first lens and the second lens on the first optical axis, the axial aberration of the imaging lens can be controlled, and the sensitivity of the imaging lens can be reduced.

[0074] In an exemplary embodiment, the effective focal length f3 of the third lens, the refractive index N3 of the third lens, and the central thickness CT3 of the third lens on the first optical axis may satisfy: -79.8 < f3×N3 / CT3 < -43.95. By reasonably configuring the relationship between the effective focal length of the third lens, the refractive index of the third lens, and the central thickness of the third lens on the first optical axis, the off-axis aberration and sensitivity of the imaging lens can be reduced, and the yield and image quality of the imaging lens can be improved.

[0075] In an exemplary embodiment, the effective focal length f2 of the second lens and the radius of curvature R3 of the object side surface of the second lens may satisfy: 1.1 < f2 / R3 ≤ 2.9. By controlling the ratio of the effective focal length of the second lens to the radius of curvature of the object side surface of the second lens, when ensuring the large aperture of the imaging lens, the second lens can have a smaller aperture, thereby reducing the longitudinal height of the imaging lens. The longitudinal height may be the height in the direction perpendicular to the lens arrangement direction from the first lens to the fourth lens.

[0076] In an exemplary embodiment, the central thickness CT2 of the second lens on the first optical axis and the central thickness CT4 of the fourth lens on the first optical axis may satisfy: 2.5 < CT2 / CT4 < 3.55. By controlling the ratio of the central thickness of the second lens on the first optical axis to the central thickness of the fourth lens on the first optical axis, the central thicknesses of the second lens and the fourth lens can be reasonably allocated, thereby improving the processability of the second lens and the fourth lens.

[0077] In an exemplary embodiment, the effective focal length f4 of the fourth lens and the combined focal length f123 of the first lens, the second lens, and the third lens may satisfy: -1.6 < f4 / f123 ≤ -1.2. By controlling the ratio of the effective focal length of the fourth lens to the combined focal length of the first lens, the second lens, and the third lens, the effective focal lengths of the respective lenses can be reasonably allocated, thereby ensuring that the imaging lens has good imaging quality during the focusing and defocusing processes.

[0078] In an exemplary embodiment, the radius of curvature R6 of the image side surface of the third lens and the radius of curvature R7 of the object side surface of the fourth lens may satisfy: -1.55 < R6 / R7 < -1.35. By reasonably configuring the ratio of the radius of curvature of the image side surface of the third lens to the radius of curvature of the object side surface of the fourth lens, the light rays exiting from the fourth lens can better match the incident position of the principal ray of the prism, thereby ensuring that the light rays are reflected multiple times inside the prism.

[0079] The imaging lens according to the above embodiment of the present application may employ four lenses and a prism. By reasonably allocating the parameters of each lens and the prism, etc., the light rays can be reflected multiple times inside the prism, realizing the long focal length characteristic of the imaging lens while ensuring the miniaturization of the imaging lens, and at the same time improving the imaging quality and yield of the imaging lens.

[0080] In an embodiment of the present application, at least one of the surfaces of each lens among the second lens to the fourth lens is an aspherical surface. The characteristics of an aspherical lens are that the curvature changes continuously from the center of the lens to the periphery of the lens. Different from a spherical lens with a constant curvature from the center of the lens to the periphery of the lens, an aspherical lens has better radius of curvature characteristics and has the advantages of improving distortion aberration and astigmatism aberration. After using an aspherical lens, it is possible to eliminate the aberration that appears during imaging as much as possible, thereby improving the imaging quality.

[0081] A second aspect of the present application provides an imaging lens, which may include an imaging lens group, a prism, and an image plane. The imaging lens group and the image plane may be located on the same side of the prism. The imaging lens group sequentially includes a first lens, a second lens, a third lens, and a fourth lens along a first optical axis from the object side to the image side. The first lens has a positive optical power, and its object side surface is convex. The second lens has a positive optical power, and its object side surface is convex. The third lens has a negative optical power, its object side surface is concave, and its image side surface is convex. The fourth lens has a negative optical power, its object side surface is convex, and its image side surface is concave. The prism has a first surface and a second surface that are parallel to each other. The number of lenses with optical power in the imaging lens may be four.

[0082] Wherein, the sum ∑CT of the central thicknesses of all the lenses from the first lens to the fourth lens on the first optical axis, the aperture b of the second surface of the prism, and the distance c between the first surface and the second surface of the prism may satisfy: 0.25 < (∑CT + c) / b < 0.3. The first lens and the second lens of the present application have positive optical powers, and their object side surfaces are convex, which can converge light rays, reduce the aperture of the rear lenses, and thus reduce the longitudinal height of the entire imaging lens; the third lens and the fourth lens have negative optical powers, and the third lens is concave-convex, and the fourth lens is convex-concave, which is beneficial to reducing chromatic aberration and improving the imaging quality of the imaging lens. At the same time, by reasonably configuring the relationship between the sum of the central thicknesses of all the lenses from the first lens to the fourth lens on the first optical axis, the aperture of the second surface of the prism, and the distance between the first surface and the second surface of the prism, while the imaging lens achieves a long focal length, the distance between the first surface and the second surface of the prism can be made smaller, thereby reducing the length of the imaging lens and facilitating the miniaturization of the imaging lens.

[0083] A third aspect of the present application provides an imaging lens, which may include an imaging lens group, a prism, and an image plane. The imaging lens group and the image plane may be located on the same side of the prism. The imaging lens group sequentially includes a first lens, a second lens, a third lens, and a fourth lens along a first optical axis from the object side to the image side. The first lens has a positive optical power, and its object side surface is convex. The second lens has a positive optical power, and its object side surface is convex. The third lens has a negative optical power, its object side surface is concave, and its image side surface is convex. The fourth lens has a negative optical power, its object side surface is convex, and its image side surface is concave. The prism has a first surface and a second surface that are parallel to each other. The number of lenses with optical power in the imaging lens may be four.

[0084] Among them, the effective focal length f1 of the first lens, the refractive index N1 of the first lens, and the curvature radius R1 of the object side surface of the first lens can satisfy: 2.3 ≤ f1×N1 / R1 < 4.8. The first lens and the second lens of the present application have positive optical powers, and the object side surfaces of both are convex surfaces, which can converge light rays, reduce the aperture of the rear lens, and thus reduce the longitudinal height of the entire imaging lens; the third lens and the fourth lens have negative optical powers, and the third lens is concave-convex, and the fourth lens is convex-concave, which is beneficial to reducing chromatic aberration and improving the imaging quality of the imaging lens. At the same time, the first lens is a glass lens, which has good temperature drift performance. Reasonably configuring the relationship between the effective focal length of the first lens, the refractive index of the first lens, and the curvature radius of the object side surface of the first lens can enable the imaging lens to achieve good imaging quality and ensure the processability of the first lens.

[0085] The fourth aspect of the present application provides such an imaging lens, which may include an imaging lens group, a prism, and an image plane. The imaging lens group and the image plane may be located on the same side of the prism. The imaging lens group sequentially includes a first lens, a second lens, a third lens, and a fourth lens along the first optical axis from the object side to the image side. The first lens has a positive optical power, and its object side surface is a convex surface. The second lens has a positive optical power, and its object side surface is a convex surface. The third lens has a negative optical power, its object side surface is a concave surface, and its image side surface is a convex surface. The fourth lens has a negative optical power, its object side surface is a convex surface, and its image side surface is a concave surface. The prism has a first surface and a second surface that are parallel to each other. The number of lenses with optical power in the imaging lens may be four.

[0086] Among them, the total effective focal length f of the imaging lens and the curvature radius R5 of the object side surface of the third lens can satisfy: -7.9 < f / R5 < -7.1. The first lens and the second lens of the present application have positive optical powers, and the object side surfaces of both are convex surfaces, which can converge light rays, reduce the aperture of the rear lens, and thus reduce the longitudinal height of the entire imaging lens; the third lens and the fourth lens have negative optical powers, and the third lens is concave-convex, and the fourth lens is convex-concave, which is beneficial to reducing chromatic aberration and improving the imaging quality of the imaging lens. At the same time, by controlling the ratio of the total effective focal length of the imaging lens to the curvature radius of the object side surface of the third lens, the effective focal length of the third lens can be reasonably allocated, reducing the off-axis aberration of the imaging lens and improving the image quality of the imaging lens.

[0087] The fifth aspect of the present application provides an imaging lens, which may include an imaging lens group, a prism, and an image plane. The imaging lens group and the image plane may be located on the same side of the prism. The imaging lens group sequentially includes a first lens, a second lens, a third lens, and a fourth lens along the first optical axis from the object side to the image side. The first lens has a positive optical power, and its object side surface is convex. The second lens has a positive optical power, and its object side surface is convex. The third lens has a negative optical power, its object side surface is concave, and its image side surface is convex. The fourth lens has a negative optical power, its object side surface is convex, and its image side surface is concave. The prism has a first surface and a second surface that are parallel to each other. The number of lenses with optical power in the imaging lens may be four.

[0088] Among them, the effective focal length f3 of the third lens, the refractive index N3 of the third lens, and the central thickness CT3 of the third lens on the first optical axis may satisfy: -79.8 < f3×N3 / CT3 < -43.95. The first lens and the second lens of the present application have positive optical powers, and their object side surfaces are convex, which can converge light rays, reduce the aperture of the rear lenses, and thus reduce the longitudinal height of the entire imaging lens; the third lens and the fourth lens have negative optical powers, and the third lens is concave-convex, and the fourth lens is convex-concave, which is beneficial to reducing chromatic aberration and improving the imaging quality of the imaging lens. At the same time, by reasonably configuring the relationship between the effective focal length of the third lens, the refractive index of the third lens, and the central thickness of the third lens on the first optical axis, the off-axis aberration and sensitivity of the imaging lens can be reduced, and the yield and image quality of the imaging lens can be improved.

[0089] The sixth aspect of the present application provides an imaging lens, which may include an imaging lens group, a prism, and an image plane. The imaging lens group and the image plane may be located on the same side of the prism. The imaging lens group sequentially includes a first lens, a second lens, a third lens, and a fourth lens along the first optical axis from the object side to the image side. The first lens has a positive optical power, and its object side surface is convex. The second lens has a positive optical power, and its object side surface is convex. The third lens has a negative optical power, its object side surface is concave, and its image side surface is convex. The fourth lens has a negative optical power, its object side surface is convex, and its image side surface is concave. The prism has a first surface and a second surface that are parallel to each other. The number of lenses with optical power in the imaging lens may be four.

[0090] Among them, the radius of curvature R6 of the image side of the third lens and the radius of curvature R7 of the object side of the fourth lens can satisfy: -1.55 < R6 / R7 < -1.35. The first lens and the second lens of the present application have positive optical powers, and the object sides of both are convex surfaces, which can converge light rays, reduce the aperture of the rear lens, and thus reduce the longitudinal height of the entire imaging lens; the third lens and the fourth lens have negative optical powers, and the third lens is concave-convex, and the fourth lens is convex-concave, which is beneficial to reducing chromatic aberration and improving the imaging quality of the imaging lens. At the same time, by reasonably configuring the ratio of the radius of curvature of the image side of the third lens to the radius of curvature of the object side of the fourth lens, the light rays emerging from the fourth lens can better match the incident position of the principal ray of the prism, thereby ensuring that the light rays are reflected multiple times inside the prism.

[0091] Those skilled in the art should understand that, without departing from the technical solutions claimed in the present application, the number of lenses constituting the imaging lens can be changed to obtain the various results and advantages described in this specification.

[0092] The following further describes specific embodiments of the imaging lens applicable to the above embodiments with reference to the accompanying drawings.

[0093] Example 1

[0094] The following refers to Figure 3 Describe the imaging lens according to Embodiment 1 of the present application.

[0095] As Figure 3 shown, the imaging lens may include an imaging lens group G1, a prism T, and an image plane IMA. The imaging lens group G1 and the image plane IMA may be located on the same side of the prism T. The imaging lens group G1 may sequentially include a first lens E1, a second lens E2, a third lens E3, and a fourth lens E4 along the first optical axis from the object side to the image side. The aperture stop STO may be disposed on the object side of the first lens E1. The positions of the fourth lens E4 and the prism T relative to the image plane IMA are fixed. The lens group formed by the first lens, the second lens, and the third lens can move relative to the fourth lens along the first optical axis. When the object distance from the imaging lens changes from far to near, by moving the lens group formed by the first lens, the second lens, and the third lens, the imaging lens can be switched between a first state and a second state to achieve focus adjustment of the imaging lens.

[0096] The first lens E1 has a positive optical power, its object side S1 is a convex surface, and its image side S2 is a concave surface. The second lens E2 has a positive optical power, its object side S3 is a convex surface, and its image side S4 is a convex surface. The third lens E3 has a negative optical power, its object side S5 is a concave surface, and its image side S6 is a convex surface. The fourth lens E4 has a negative optical power, its object side S7 is a convex surface, and its image side S8 is a concave surface. It should be noted that the surfaces S1-S8 are in Figure 3Not shown in the figure.

[0097] In the example, an optical element E5 disposed on the second optical axis may also be included between the prism T and the image plane IMA. The optical element E5 may be, for example, a filter. Light from the object sequentially passes through the first lens E1, the second lens E2, the third lens E3, and the fourth lens E4, and after being reflected multiple times (e.g., 5 times) inside the prism T, passes through the optical element E5 and forms an image on the image plane IMA.

[0098] Table 1 shows the basic parameter table of the imaging lens of Example 1, where the units of the radius of curvature and the thickness / distance are both millimeters (mm).

[0099]

[0100] Table 1

[0101] In this embodiment, the object side and the image side of any one of the second lens E2 to the fourth lens E4 are both aspherical surfaces. The surface profile x of each aspherical lens can be defined by, but not limited to, the following aspherical formula:

[0102]

[0103] Where x is the sagitta, the distance from the vertex of the aspherical surface when the aspherical surface is at a position with a height of h along the optical axis; c is the paraxial curvature of the aspherical surface, c = 1 / R (i.e., the paraxial curvature c is the reciprocal of the radius of curvature R in Table 1 above); k is the conic coefficient; Ai is the correction coefficient of the i-th order of the aspherical surface. Table 2 gives the higher-order term coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, A28, and A30 that can be used for the aspherical surfaces S3 - S8 in Example 1.

[0104]

[0105]

[0106] Table 2

[0107] Table 3 shows the values of the distance W between the object and the imaging lens, the spacing distance D between the third lens and the fourth lens on the first optical axis, and the total effective focal length f of the imaging lens in the first state and the second state. Where the units of W, f, and D are all millimeters (mm).

[0108] State First state Second state W Infinity 800 f 33.12 32.25 D 0.66 1.09

[0109] Table 3

[0110] Figure 4AThe axial chromatic aberration curve of the imaging lens in the first state of Embodiment 1 is shown, which represents the deviation of the convergence points of light rays with different wavelengths after passing through the imaging lens. Figure 4B The astigmatism curve of the imaging lens in the first state of Embodiment 1 is shown, which represents the meridional image plane curvature and sagittal image plane curvature corresponding to different image heights. Figure 4C The distortion curve of the imaging lens in the first state of Embodiment 1 is shown, which represents the distortion magnitude values corresponding to different image heights. Figure 4D The longitudinal chromatic aberration curve of the imaging lens in the first state of Embodiment 1 is shown, which represents the deviation of different image heights on the image plane after light rays pass through the lens. According to Figures 4A to 4D it can be known that the imaging lens of Embodiment 1 can achieve good imaging quality in the first state.

[0111] Figure 5A The axial chromatic aberration curve of the imaging lens in the second state of Embodiment 1 is shown, which represents the deviation of the convergence points of light rays with different wavelengths after passing through the imaging lens. Figure 5B The astigmatism curve of the imaging lens in the second state of Embodiment 1 is shown, which represents the meridional image plane curvature and sagittal image plane curvature corresponding to different image heights. Figure 5C The distortion curve of the imaging lens in the second state of Embodiment 1 is shown, which represents the distortion magnitude values corresponding to different image heights. Figure 5D The longitudinal chromatic aberration curve of the imaging lens in the second state of Embodiment 1 is shown, which represents the deviation of different image heights on the image plane after light rays pass through the lens. According to Figures 5A to 5D it can be known that the imaging lens of Embodiment 1 can achieve good imaging quality in the second state.

[0112] Example 2

[0113] The following refers to Figure 6 to describe the imaging lens according to Embodiment 2 of the present application.

[0114] As Figure 6 shown, the imaging lens may include an imaging lens group G1, a prism T, and an image plane IMA. The imaging lens group G1 and the image plane IMA may be located on the same side of the prism T. The imaging lens group G1 may sequentially include a first lens E1, a second lens E2, a third lens E3, and a fourth lens E4 along the first optical axis from the object side to the image side. The aperture stop STO may be disposed on the object side of the first lens E1. The positions of the fourth lens E4 and the prism T relative to the image plane IMA are fixed. The lens group formed by the first lens, the second lens, and the third lens may move relative to the fourth lens along the first optical axis. When the distance between the object and the imaging lens changes from far to near, by moving the lens group formed by the first lens, the second lens, and the third lens, the imaging lens can be switched between the first state and the second state to achieve focus adjustment of the imaging lens.

[0115] The first lens E1 has a positive optical power, its object side S1 is convex, and its image side S2 is concave. The second lens E2 has a positive optical power, its object side S3 is convex, and its image side S4 is convex. The third lens E3 has a negative optical power, its object side S5 is concave, and its image side S6 is convex. The fourth lens E4 has a negative optical power, its object side S7 is convex, and its image side S8 is concave. It should be noted that the surfaces S1 - S8 are not shown in Figure 6 the figure.

[0116] In the example, an optical element E5 disposed on the second optical axis may further be included between the prism T and the image plane IMA. The optical element E5 may be, for example, a filter. The light from the object sequentially passes through the first lens E1, the second lens E2, the third lens E3, the fourth lens E4, and after being reflected multiple times (e.g., 5 times) inside the prism T, passes through the optical element E5 and forms an image on the image plane IMA.

[0117] Table 4 shows the basic parameter table of the imaging lens of Embodiment 2, where the units of the radius of curvature and the thickness / distance are both millimeters (mm).

[0118]

[0119] Table 4

[0120] In this embodiment, the object side and the image side of any one of the second lens E2 to the fourth lens E4 are aspherical surfaces. Table 5 gives the higher-order term coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, A28, and A30 for the aspherical surfaces S3 - S8 in Embodiment 2.

[0121] Face number A4 A6 A8 A10 A12 A14 A16 S3 4.88E-01 -3.72E-02 -8.10E-03 -1.07E-03 -1.42E-04 1.88E-04 -1.97E-04 S4 6.70E-01 -9.91E-02 -3.22E-03 2.50E-03 1.10E-03 6.21E-04 -1.63E-03 S5 2.23E+00 -2.57E-01 5.28E-02 -1.33E-02 4.72E-03 -2.17E-04 -1.23E-03 S6 1.78E+00 -9.42E-02 3.60E-02 -6.48E-03 1.51E-03 -8.03E-06 -2.76E-04 S7 -1.23E+00 4.98E-02 -1.38E-02 -3.40E-04 -7.56E-05 -1.62E-04 -1.38E-06 S8 -8.15E-01 7.97E-02 -9.97E-03 1.07E-03 -2.09E-04 2.65E-05 -6.46E-05 Face number A18 A20 A22 A24 A26 A28 A30 S3 5.12E-05 1.72E-05 6.61E-07 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S4 2.63E-04 1.43E-04 -1.07E-04 -1.86E-07 0.00E+00 0.00E+00 0.00E+00 S5 4.44E-04 -1.44E-04 -3.39E-05 -2.69E-08 0.00E+00 0.00E+00 0.00E+00 S6 1.30E-04 3.21E-06 -1.43E-06 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S7 -1.63E-05 -1.99E-05 -4.09E-08 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S8 3.67E-05 -5.65E-05 9.06E-06 4.70E-07 0.00E+00 0.00E+00 0.00E+00

[0122] Table 5

[0123] Table 6 shows the values of the distance W between the object and the imaging lens, the spacing distance D between the third lens and the fourth lens on the first optical axis, and the total effective focal length f of the imaging lens in the first state and the second state in Embodiment 2, where the units of W, f, and D are all millimeters (mm).

[0124] State First state Second state W Infinity 800 f 33.12 32.25 D 0.46 0.87

[0125] Table 6

[0126] Figure 7A shows the axial chromatic aberration curve of the imaging lens in the first state of Embodiment 2, which represents the deviation of the convergence points of light rays of different wavelengths after passing through the imaging lens. Figure 7BThe astigmatism curve showing the first state of the imaging lens of Embodiment 2 represents the meridional image plane curvature and sagittal image plane curvature corresponding to different image heights. Figure 7C The distortion curve showing the first state of the imaging lens of Embodiment 2 represents the distortion magnitude values corresponding to different image heights. Figure 7D The longitudinal chromatic aberration curve showing the first state of the imaging lens of Embodiment 2 represents the deviation of different image heights on the image plane after light passes through the lens. According to Figures 7A to 7D it can be seen that the imaging lens of Embodiment 2 can achieve good imaging quality in the first state.

[0127] Figure 8A The axial chromatic aberration curve showing the second state of the imaging lens of Embodiment 2 represents the deviation of the convergence points of light rays with different wavelengths after passing through the imaging lens. Figure 8B The astigmatism curve showing the second state of the imaging lens of Embodiment 2 represents the meridional image plane curvature and sagittal image plane curvature corresponding to different image heights. Figure 8C The distortion curve showing the second state of the imaging lens of Embodiment 2 represents the distortion magnitude values corresponding to different image heights. Figure 8D The longitudinal chromatic aberration curve showing the second state of the imaging lens of Embodiment 2 represents the deviation of different image heights on the image plane after light passes through the lens. According to Figures 8A to 8D it can be seen that the imaging lens of Embodiment 2 can achieve good imaging quality in the second state.

[0128] Example 3

[0129] The following will refer to Figure 9 describe the imaging lens according to Embodiment 3 of the present application.

[0130] As Figure 9 shown, the imaging lens may include an imaging lens group G1, a prism T, and an image plane IMA. The imaging lens group G1 and the image plane IMA may be located on the same side of the prism T. The imaging lens group G1 may sequentially include a first lens E1, a second lens E2, a third lens E3, and a fourth lens E4 along the first optical axis from the object side to the image side. The aperture stop STO may be disposed on the object side of the first lens E1. The positions of the fourth lens E4 and the prism T relative to the image plane IMA are fixed. The lens group formed by the first lens, the second lens, and the third lens may move relative to the fourth lens along the first optical axis. When the distance between the object and the imaging lens changes from far to near, by moving the lens group formed by the first lens, the second lens, and the third lens, the imaging lens can be switched between the first state and the second state to achieve focus adjustment of the imaging lens.

[0131] The first lens E1 has a positive focal power, with its object side S1 being convex and its image side S2 being convex. The second lens E2 has a positive focal power, with its object side S3 being convex and its image side S4 being concave. The third lens E3 has a negative focal power, with its object side S5 being concave and its image side S6 being convex. The fourth lens E4 has a negative focal power, with its object side S7 being convex and its image side S8 being concave. It should be noted that the surfaces S1 - S8 are not shown in Figure 9 the text.

[0132] In the example, an optical element E5 disposed on the second optical axis may also be included between the prism T and the image plane IMA. The optical element E5 may be, for example, a filter. Light from the object sequentially passes through the first lens E1, the second lens E2, the third lens E3, the fourth lens E4, and after being reflected multiple times (e.g., 5 times) inside the prism T, passes through the optical element E5 and forms an image on the image plane IMA.

[0133] Table 7 shows the basic parameter table of the imaging lens of Example 3, where the units of the radius of curvature and the thickness / distance are both millimeters (mm).

[0134]

[0135]

[0136] Table 7

[0137] In this embodiment, the object side and the image side of any one of the second lens E2 to the fourth lens E4 are both aspherical surfaces. Table 8 gives the higher-order term coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, A28, and A30 for the aspherical surfaces S3 - S8 in Example 3.

[0138] Face number A4 A6 A8 A10 A12 A14 A16 S3 4.46E-01 -5.17E-03 -1.98E-03 -4.03E-03 1.92E-04 -3.36E-04 4.23E-04 S4 7.26E-01 -7.70E-02 -1.36E-03 -5.85E-03 3.88E-03 4.20E-04 8.37E-04 S5 3.58E+00 1.05E-01 3.30E-01 1.48E-01 1.47E-01 1.07E-01 9.02E-02 S6 1.80E+00 -1.73E-01 5.41E-02 -1.44E-02 4.59E-03 -1.36E-03 7.09E-04 S7 -1.06E+00 2.00E-02 -1.19E-02 6.77E-05 -4.81E-04 -1.17E-04 -5.96E-05 S8 -6.19E-01 5.63E-02 -5.73E-03 1.46E-03 -3.02E-04 -5.26E-05 -4.37E-05 Face number A18 A20 A22 A24 A26 A28 A30 S3 1.16E-04 -9.36E-05 -6.53E-06 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S4 -6.53E-04 -8.60E-05 2.74E-04 8.30E-06 0.00E+00 0.00E+00 0.00E+00 S5 6.90E-02 5.29E-02 3.82E-02 2.05E-02 0.00E+00 0.00E+00 0.00E+00 S6 -7.72E-05 1.97E-04 3.49E-07 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S7 -9.87E-06 9.88E-06 -8.50E-07 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S8 -1.16E-05 1.18E-06 2.14E-06 0.00E+00 0.00E+00 0.00E+00 0.00E+00

[0139] Table 8

[0140] Table 9 shows the values of the distance W between the object and the imaging lens, the spacing distance D between the third lens and the fourth lens on the first optical axis, and the total effective focal length f of the imaging lens in the first state and the second state in Example 3, where the units of W, f, and D are all millimeters (mm).

[0141] State First state Second state W Infinity 800 f 33.12 32.21 D 0.40 0.83

[0142] Table 9

[0143] Figure 10A shows the axial chromatic aberration curve of the imaging lens in the first state of Example 3, which represents the deviation of the convergence points of light rays of different wavelengths after passing through the imaging lens. Figure 10BThe astigmatism curve of the imaging lens in the first state of Embodiment 3 is shown, which represents the meridional image plane curvature and the sagittal image plane curvature corresponding to different image heights. Figure 10C The distortion curve of the imaging lens in the first state of Embodiment 3 is shown, which represents the distortion magnitude values corresponding to different image heights. Figure 10D The longitudinal chromatic aberration curve of the imaging lens in the first state of Embodiment 3 is shown, which represents the deviation of different image heights of light rays on the image plane after passing through the lens. According to Figures 10A to 10D It can be known that the imaging lens of Embodiment 3 can achieve good imaging quality in the first state.

[0144] Figure 11A The axial chromatic aberration curve of the imaging lens in the second state of Embodiment 3 is shown, which represents the deviation of the convergence points of light rays with different wavelengths after passing through the imaging lens. Figure 11B The astigmatism curve of the imaging lens in the second state of Embodiment 3 is shown, which represents the meridional image plane curvature and the sagittal image plane curvature corresponding to different image heights. Figure 11C The distortion curve of the imaging lens in the second state of Embodiment 3 is shown, which represents the distortion magnitude values corresponding to different image heights. Figure 11D The longitudinal chromatic aberration curve of the imaging lens in the second state of Embodiment 3 is shown, which represents the deviation of different image heights of light rays on the image plane after passing through the lens. According to Figures 11A to 11D It can be known that the imaging lens of Embodiment 3 can achieve good imaging quality in the second state.

[0145] Example 4

[0146] The following refers to Figure 12 Describe the imaging lens according to Embodiment 4 of the present application.

[0147] As Figure 12 shown, the imaging lens may include an imaging lens group G1, a prism T, and an image plane IMA. The imaging lens group G1 and the image plane IMA may be located on the same side of the prism T. The imaging lens group G1 may sequentially include a first lens E1, a second lens E2, a third lens E3, and a fourth lens E4 along the first optical axis from the object side to the image side. The aperture stop STO may be disposed on the object side of the first lens E1. The positions of the fourth lens E4 and the prism T relative to the image plane IMA are fixed. The lens group formed by the first lens, the second lens, and the third lens may move relative to the fourth lens along the first optical axis. When the object distance from the imaging lens changes from far to near, by moving the lens group formed by the first lens, the second lens, and the third lens, the imaging lens can be switched between the first state and the second state to achieve focus adjustment of the imaging lens.

[0148] The first lens E1 has a positive focal power, with its object side S1 being convex and its image side S2 being convex. The second lens E2 has a positive focal power, with its object side S3 being convex and its image side S4 being concave. The third lens E3 has a negative focal power, with its object side S5 being concave and its image side S6 being convex. The fourth lens E4 has a negative focal power, with its object side S7 being convex and its image side S8 being concave. It should be noted that the surfaces S1 - S8 are not shown in Figure 12 as follows.

[0149] In the example, an optical element E5 disposed on the second optical axis may also be included between the prism T and the image plane IMA. The optical element E5 may be, for example, a filter. Light from the object sequentially passes through the first lens E1, the second lens E2, the third lens E3, the fourth lens E4, and after being reflected multiple times (e.g., 5 times) inside the prism T, passes through the optical element E5 and forms an image on the image plane IMA.

[0150] Table 10 shows the basic parameter table of the imaging lens of Example 4, where the units of the radius of curvature and the thickness / distance are both millimeters (mm).

[0151]

[0152]

[0153] Table 10

[0154] In this embodiment, the object side and the image side of any one of the second lens E2 to the fourth lens E4 are both aspherical surfaces. Table 11 gives the higher - order term coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, A28, and A30 that can be used for the aspherical surfaces S3 - S8 in Example 4.

[0155] Face number A4 A6 A8 A10 A12 A14 A16 S3 4.64E-01 -1.43E-02 -7.01E-03 -3.19E-03 8.41E-06 3.11E-04 8.33E-04 S4 7.07E-01 -6.89E-02 -3.30E-03 -3.80E-03 6.58E-04 5.59E-04 1.32E-03 S5 2.99E+00 -1.47E-01 1.20E-01 -9.33E-03 1.40E-02 -4.40E-04 2.89E-03 S6 1.72E+00 -1.69E-01 5.42E-02 -1.43E-02 5.21E-03 -2.01E-03 8.95E-04 S7 -1.23E+00 4.81E-02 -1.37E-02 6.42E-04 2.18E-04 3.03E-04 3.01E-04 S8 -7.28E-01 8.20E-02 -7.59E-03 2.39E-03 -9.73E-05 6.27E-04 2.24E-04 Face number A18 A20 A22 A24 A26 A28 A30 S3 2.32E-04 -1.14E-04 -7.11E-06 -6.72E-07 0.00E+00 0.00E+00 0.00E+00 S4 -2.34E-04 -3.79E-04 8.18E-05 2.02E-06 0.00E+00 0.00E+00 0.00E+00 S5 -5.09E-04 5.92E-04 5.01E-05 3.28E-05 0.00E+00 0.00E+00 0.00E+00 S6 -4.61E-04 2.76E-04 4.27E-07 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S7 1.93E-04 -5.11E-05 -4.34E-05 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S8 2.72E-04 -5.18E-05 -2.74E-07 -5.82E-08 0.00E+00 0.00E+00 0.00E+00

[0156] Table 11

[0157] Table 12 shows the values of the distance W between the object and the imaging lens, the interval distance D between the third lens and the fourth lens on the first optical axis, and the total effective focal length f of the imaging lens in the first state and the second state in Example 4, where the units of W, f, and D are all millimeters (mm).

[0158] State First state Second state W Infinity 800 f 33.12 31.97 D 0.48 0.78

[0159] Table 12

[0160] Figure 13A shows the axial chromatic aberration curve of the imaging lens in the first state of Example 4, which represents the deviation of the convergence points of light rays of different wavelengths after passing through the imaging lens. Figure 13BThe astigmatism curve of the imaging lens in the first state of Embodiment 4 is shown, which represents the meridional image plane curvature and sagittal image plane curvature corresponding to different image heights. Figure 13C The distortion curve of the imaging lens in the first state of Embodiment 4 is shown, which represents the distortion magnitude values corresponding to different image heights. Figure 13D The longitudinal chromatic aberration curve of the imaging lens in the first state of Embodiment 4 is shown, which represents the deviation of different image heights on the image plane after light passes through the lens. According to Figures 13A to 13D it can be known that the imaging lens of Embodiment 4 can achieve good imaging quality in the first state.

[0161] Figure 14A The axial chromatic aberration curve of the imaging lens in the second state of Embodiment 4 is shown, which represents the deviation of the focus points of light rays with different wavelengths after passing through the imaging lens. Figure 14B The astigmatism curve of the imaging lens in the second state of Embodiment 4 is shown, which represents the meridional image plane curvature and sagittal image plane curvature corresponding to different image heights. Figure 14C The distortion curve of the imaging lens in the second state of Embodiment 4 is shown, which represents the distortion magnitude values corresponding to different image heights. Figure 14D The longitudinal chromatic aberration curve of the imaging lens in the second state of Embodiment 4 is shown, which represents the deviation of different image heights on the image plane after light passes through the lens. According to Figures 14A to 14D it can be known that the imaging lens of Embodiment 4 can achieve good imaging quality in the second state.

[0162] Example 5

[0163] The following refers to Figure 15 to describe the imaging lens according to Embodiment 5 of the present application.

[0164] As Figure 15 shown, the imaging lens may include an imaging lens group G1, a prism T, and an image plane IMA. The imaging lens group G1 and the image plane IMA may be located on the same side of the prism T. The imaging lens group G1 may sequentially include a first lens E1, a second lens E2, a third lens E3, and a fourth lens E4 along the first optical axis from the object side to the image side. The aperture stop STO may be disposed on the object side of the first lens E1. The positions of the fourth lens E4 and the prism T relative to the image plane IMA are fixed. The lens group formed by the first lens, the second lens, and the third lens may move relative to the fourth lens along the first optical axis. When the object distance from the imaging lens changes from far to near, by moving the lens group formed by the first lens, the second lens, and the third lens, the imaging lens can be switched between the first state and the second state to achieve focus adjustment of the imaging lens.

[0165] The first lens E1 has a positive focal power, its object side S1 is convex, and its image side S2 is concave. The second lens E2 has a positive focal power, its object side S3 is convex, and its image side S4 is convex. The third lens E3 has a negative focal power, its object side S5 is concave, and its image side S6 is convex. The fourth lens E4 has a negative focal power, its object side S7 is convex, and its image side S8 is concave. It should be noted that the surfaces S1 - S8 are not shown in Figure 15 the figure.

[0166] In the example, an optical element E5 disposed on the second optical axis may further be included between the prism T and the image plane IMA. The optical element E5 may be, for example, a filter. The light from the object sequentially passes through the first lens E1, the second lens E2, the third lens E3, and the fourth lens E4, and after being reflected multiple times (e.g., 5 times) inside the prism T, passes through the optical element E5 and forms an image on the image plane IMA.

[0167] Table 13 shows the basic parameter table of the imaging lens of Example 5, where the units of the radius of curvature and the thickness / distance are both millimeters (mm).

[0168]

[0169]

[0170] Table 13

[0171] In this embodiment, the object side and the image side of any one of the second lens E2 to the fourth lens E4 are aspherical surfaces. Table 14 gives the higher-order term coefficients A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, A28, and A30 that can be used for the aspherical surfaces S3 - S8 in Example 5.

[0172] Face number A4 A6 A8 A10 A12 A14 A16 S3 5.45E-01 -3.56E-02 -7.30E-03 -1.96E-03 -4.71E-04 1.88E-04 -6.80E-05 S4 7.62E-01 -1.04E-01 1.17E-03 3.30E-04 6.65E-04 1.47E-03 -2.93E-04 S5 2.99E+00 3.39E-03 1.21E-01 2.54E-02 2.01E-02 9.49E-03 4.43E-03 S6 1.42E+00 -6.02E-02 2.19E-02 -3.09E-03 4.97E-04 2.36E-04 -1.74E-04 S7 -1.12E+00 7.00E-02 -1.31E-02 5.84E-04 -1.42E-04 -7.38E-05 8.89E-06 S8 -8.57E-01 9.30E-02 -1.25E-02 1.08E-03 -2.35E-04 -5.59E-05 5.83E-06 Face number A18 A20 A22 A24 A26 A28 A30 S3 2.83E-05 3.89E-06 2.79E-07 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S4 1.16E-04 1.98E-05 -2.46E-05 -6.49E-08 0.00E+00 0.00E+00 0.00E+00 S5 2.90E-03 1.35E-03 7.61E-04 3.30E-04 0.00E+00 0.00E+00 0.00E+00 S6 9.49E-05 3.02E-05 -6.89E-07 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S7 3.08E-06 -1.08E-05 2.49E-07 0.00E+00 0.00E+00 0.00E+00 0.00E+00 S8 1.12E-06 -1.22E-05 1.12E-05 5.79E-07 4.39E-08 0.00E+00 0.00E+00

[0173] Table 14

[0174] Table 15 shows the values of the distance W between the object and the imaging lens, the interval distance D between the third lens and the fourth lens on the first optical axis, and the total effective focal length f of the imaging lens in the first state and the second state in Example 5, where the units of W, f, and D are all millimeters (mm).

[0175] State First state Second state W Infinity 800 f 34.00 33.06 D 0.61 1.04

[0176] Table 15

[0177] Figure 16A shows the axial chromatic aberration curve of the imaging lens in the first state of Example 5, which represents the deviation of the convergence points of light rays of different wavelengths after passing through the imaging lens. Figure 16BThe astigmatism curve of the imaging lens in the first state of Embodiment 5 is shown, which represents the meridional image plane curvature and the sagittal image plane curvature corresponding to different image heights. Figure 16C The distortion curve of the imaging lens in the first state of Embodiment 5 is shown, which represents the distortion magnitude values corresponding to different image heights. Figure 16D The longitudinal chromatic aberration curve of the imaging lens in the first state of Embodiment 5 is shown, which represents the deviation of different image heights of light rays on the image plane after passing through the lens. According to Figures 16A to 16D it can be known that the imaging lens of Embodiment 5 can achieve good imaging quality in the first state.

[0178] Figure 17A The axial chromatic aberration curve of the imaging lens in the second state of Embodiment 5 is shown, which represents the deviation of the convergence points of light rays with different wavelengths after passing through the imaging lens. Figure 17B The astigmatism curve of the imaging lens in the second state of Embodiment 5 is shown, which represents the meridional image plane curvature and the sagittal image plane curvature corresponding to different image heights. Figure 17C The distortion curve of the imaging lens in the second state of Embodiment 5 is shown, which represents the distortion magnitude values corresponding to different image heights. Figure 17D The longitudinal chromatic aberration curve of the imaging lens in the second state of Embodiment 5 is shown, which represents the deviation of different image heights of light rays on the image plane after passing through the lens. According to Figures 17A to 17D it can be known that the imaging lens of Embodiment 5 can achieve good imaging quality in the second state.

[0179] Table 16 shows the values of parameters such as f1, f2, f3, f4, f12, f123, a, b, c, SAG11, and SAG21 for each of Embodiments 1 - 5. Among them, a, b, and c can be measured according to Figure 2 the marking method shown.

[0180] Parameter / Example 1 2 3 4 5 f1 (mm) 21.77 20.49 19.30 18.82 20.69 f2 (mm) 17.90 21.51 24.32 21.05 18.70 f3 (mm) -19.83 -23.79 -21.69 -24.76 -20.04 f4 (mm) -28.62 -27.37 -27.28 -18.18 -27.63 f12 (mm) 10.30 11.03 10.87 10.08 10.33 f123 (mm) 18.49 18.11 18.39 15.18 18.45 a (mm) 13.79 14.96 14.67 14.90 14.62 b (mm) 27.71 29.26 29.00 28.86 29.94 c (mm) 4.00 4.00 4.09 4.23 4.00 SAG11 (mm) 1.46 1.57 0.78 0.81 1.50 SAG21 (mm) 1.20 1.03 1.61 1.66 1.13

[0181] Table 16

[0182] Table 17 shows the values of the conditional expressions for each of Embodiments 1 - 5. Among them, the first state of the imaging lens is abbreviated as "State I", and the second state of the imaging lens is abbreviated as "State II".

[0183]

[0184] Table 17

[0185] Table 18 shows the values of the conditional expressions for each of Embodiments 1 - 5.

[0186] Condition / Example 1 2 3 4 5 (∑CT + c) / b 0.28 0.28 0.26 0.27 0.27 f1 × N1 / R1 4.76 4.24 2.34 2.30 4.40 (V1 + V3) / (f1 - f3) 1.80 1.62 2.01 1.62 1.88 (CT2 + CT3) / T23 2.90 3.27 1.41 1.54 2.86 SAG21 / SAG11 0.82 0.66 2.07 2.06 0.75 f12 / T12 102.99 110.35 108.71 100.82 103.33 f3 × N3 / CT3 -43.97 -76.57 -69.23 -79.79 -44.70 f2 / R3 1.32 1.16 2.90 2.46 1.15 CT2 / CT4 2.94 3.54 2.51 2.56 2.90 f4 / f123 -1.55 -1.51 -1.48 -1.20 -1.50 R6 / R7 -1.48 -1.36 -1.54 -1.46 -1.49

[0187] Table 18

[0188] The present application also provides an imaging device, and its electronic photosensitive element may be a charge-coupled device (CCD) or a complementary metal-oxide-semiconductor element (CMOS). The imaging device may be an independent imaging device such as a digital camera, or an imaging module integrated on a mobile electronic device such as a mobile phone. The imaging device is equipped with the imaging lens described above.

[0189] The above description is only a preferred embodiment of the present application and an explanation of the technical principles applied. 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 the specific combination of the above technical features, and 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 technical solution formed by mutually replacing the above features with the technical features (but not limited to) having similar functions disclosed in the present application.

Claims

1. Imaging lens, characterized in that, It includes an imaging lens group, a prism, and an image plane, where the imaging lens group and the image plane are located on the same side of the prism; among them, The imaging lens group sequentially includes, from the object side to the image side along the first optical axis: A first lens with positive optical power, whose object side surface is convex; A second lens with positive optical power, whose object side surface is convex; A third lens with negative optical power, whose object side surface is concave and image side surface is convex; and A fourth lens with negative optical power, whose object side surface is convex and image side surface is concave; The prism has a first surface and a second surface that are parallel to each other; The number of lenses with optical power in the imaging lens is four; The total effective focal length f of the imaging lens, the aperture a of the first surface of the prism, the aperture b of the second surface of the prism, and the distance c between the first surface and the second surface of the prism satisfy: 52.7mm < f×((b - a) / 2 / c) < 65.15mm.

2. The imaging lens according to claim 1, wherein The sum ∑CT of the central thicknesses of all the lenses from the first lens to the fourth lens on the first optical axis, the aperture b of the second surface of the prism, and the distance c between the first surface and the second surface of the prism satisfy: 0.25 < (∑CT + c) / b < 0.

3.

3. The imaging lens according to claim 1, wherein The effective focal length f1 of the first lens, the refractive index N1 of the first lens, and the curvature radius R1 of the object side surface of the first lens satisfy: 2.3 ≤ f1×N1 / R1 < 4.

8.

4. The imaging lens according to claim 1, characterized in that, The total effective focal length f of the imaging lens and the curvature radius R5 of the object side surface of the third lens satisfy: -7.9 < f / R5 < -7.

1.

5. The imaging lens according to claim 1, wherein The central thickness CT2 of the second lens on the first optical axis, the central thickness CT3 of the third lens on the first optical axis, and the interval distance T23 between the second lens and the third lens on the first optical axis satisfy: 1.4 < (CT2 + CT3) / T23 < 3.

3.

6. The imaging lens according to any one of claims 1-5, characterized in that, The effective focal length f1 of the first lens, the Abbe number V1 of the first lens, the effective focal length f3 of the third lens, and the Abbe number V3 of the third lens satisfy: 1.6mm -1 <(V1 + V3) / (f1 - f3) < 2.05mm -1 .

7. The imaging lens according to any one of claims 1-5, characterized in that, The axial distance SAG11 between the intersection point of the object side surface of the first lens and the first optical axis and the vertex of the effective semi - aperture of the object side surface of the first lens and the axial distance SAG21 between the intersection point of the object side surface of the second lens and the first optical axis and the vertex of the effective semi - aperture of the object side surface of the second lens satisfy: 0.65 < SAG21 / SAG11 < 2.

1.

8. The imaging lens according to any one of claims 1-5, characterized in that, The combined focal length f12 of the first lens and the second lens and the interval distance T12 between the first lens and the second lens on the first optical axis satisfy: 100.8 < f12 / T12 < 110.

4.

9. The imaging lens according to any one of claims 1-5, characterized in that, The effective focal length f3 of the third lens, the refractive index N3 of the third lens, and the central thickness CT3 of the third lens on the first optical axis satisfy: -79.8 < f3×N3 / CT3 < -43.

95.

10. The imaging lens according to any one of claims 1-5, characterized in that, The effective focal length f2 of the second lens and the curvature radius R3 of the object side surface of the second lens satisfy: 1.1 < f2 / R3 ≤ 2.

9.

11. The imaging lens according to any one of claims 1-5, characterized in that, The central thickness CT2 of the second lens on the first optical axis and the central thickness CT4 of the fourth lens on the first optical axis satisfy: 2.5 < CT2 / CT4 < 3.

55.

12. The imaging lens according to any one of claims 1-5, characterized in that, The effective focal length f4 of the fourth lens and the combined focal length f123 of the first lens, the second lens, and the third lens satisfy: -1.6 < f4 / f123 ≤ -1.

2.

13. The imaging lens according to any one of claims 1-5, characterized in that, The radius of curvature R6 of the image side of the third lens and the radius of curvature R7 of the object side of the fourth lens satisfy: -1.55 < R6 / R7 < -1.

35.

14. The imaging lens according to any one of claims 1-5, characterized in that, The positions of the fourth lens and the prism with respect to the image plane are fixed, and the distance of the lens group formed by the first lens, the second lens, and the third lens on the first optical axis with respect to the fourth lens is adjustable; The total effective focal length f of the imaging lens satisfies: 31.95 mm < f ≤ 34.0 mm.

15. The imaging lens according to any one of claims 1-5, characterized in that, The on-axis distance from the image side of the fourth lens to the first surface of the prism is greater than the on-axis distance from the image side of the fourth lens to the second surface of the prism.

Images