Telephoto lens

Abstract

The utility model discloses a telephoto lens. The telephoto lens comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens which are sequentially arranged along an optical axis from an object side to an image side, the first lens is a glass spherical lens with positive focal power; the second lens is a plastic aspheric lens with negative focal power; the third lens is a glass spherical lens with positive focal power; the fourth lens is a glass spherical lens with focal power; the fifth lens is a plastic aspheric lens with negative focal power; the sixth lens is a plastic aspheric lens with positive focal power; the seventh lens is a plastic aspheric lens with positive focal power; wherein the optical system total length TTL of the telephoto lens and the imaging target surface IMH meet the condition that TTL / IMH is less than or equal to 3.2. By adopting the technical scheme, on the premise of ensuring that the telephoto lens has a small size, the telephoto lens can have a large imaging target surface, and the high-quality imaging requirement is met.

Description

Technical Field

[0001] The embodiments of the utility model relate to the technical field of optical devices, and in particular to a telephoto lens. Background Art

[0002] Telephoto lenses have a long focal length and a strong advantage in telephoto photography, making them widely used in automotive forward-looking systems, driver assistance systems, and telephoto systems. However, in existing technologies, the focal length of telephoto lenses is limited, resulting in a relatively long overall length and high cost for finished products. Utility Model Content

[0003] The utility model provides a telephoto lens, which can ensure that the telephoto lens has a larger imaging target surface, lower cost and higher imaging quality while ensuring that the telephoto lens has a smaller volume.

[0004] The utility model provides a telephoto lens, which comprises: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens and a seventh lens, which are arranged in sequence along the optical axis from the object side to the image side;

[0005] The first lens is a glass spherical lens with positive optical power;

[0006] The second lens is a plastic aspheric lens with negative optical power;

[0007] The third lens is a glass spherical lens with positive optical power;

[0008] The fourth lens is a glass spherical lens with optical power;

[0009] The fifth lens is a plastic aspherical lens with negative optical power;

[0010] The sixth lens is a plastic aspheric lens with positive optical power;

[0011] The seventh lens is a plastic aspherical lens with positive optical power;

[0012] The total length TTL of the optical system of the telephoto lens and the imaging target surface IMH satisfy the following relationship: TTL / IMH≤3.2.

[0013] Optionally, the optical power of the first lens satisfies:

[0014] 0.44≤Φ1 / Φ≤0.686;

[0015] Wherein, Φ1 is the optical focal length of the first lens, and Φ is the optical focal length of the telephoto lens.

[0016] Optionally, the optical powers of the second lens, the third lens, and the fourth lens satisfy:

[0017] -0.993≤Φ2 / Φ≤-0.60;

[0018] 0.331≤Φ3 / Φ≤0.652;

[0019] -0.701≤Φ4 / Φ≤0.14;

[0020] Φ2 is the focal power of the second lens, Φ3 is the focal power of the third lens, Φ4 is the focal power of the fourth lens, and Φ is the focal power of the telephoto lens.

[0021] Optionally, the refractive index and Abbe number of the third lens and the fourth lens satisfy:

[0022] 1.41≤Nd3≤1.59;

[0023] 57.07≤Vd3≤100.03;

[0024] 1.78≤Nd4≤1.85;

[0025] 25≤Vd4≤49;

[0026] Wherein, Nd3 is the refractive index of the third lens, Vd3 is the Abbe number of the third lens, Nd4 is the refractive index of the fourth lens, and Vd4 is the Abbe number of the fourth lens.

[0027] Optionally, the second lens is a convex-concave lens.

[0028] Optionally, the third lens is a biconvex lens.

[0029] Optionally, the optical powers of the fifth lens, the sixth lens, and the seventh lens satisfy:

[0030] -1.231≤Φ5 / Φ≤-0.545;

[0031] 0.232≤Φ6 / Φ≤0.92;

[0032] 0.326≤Φ7 / Φ≤1.291;

[0033] Φ5 is the optical power of the fifth lens, Φ6 is the optical power of the sixth lens, Φ7 is the optical power of the seventh lens, and Φ is the optical power of the telephoto lens.

[0034] Optionally, the fifth lens is a concave-convex lens.

[0035] Optionally, the seventh lens is a convex-concave lens.

[0036] Optionally, the telephoto lens further includes an aperture; the aperture is located on the object side of the second lens.

[0037] The technical solution of the utility model adopts seven lenses with optical power to form a telephoto lens, reasonably distributes the optical power and surface shape of each lens, and sets the total optical system length TTL and the imaging target surface IMH of the telephoto lens to meet TTL / IMH≤3.2, so that the telephoto lens can simultaneously meet the requirements of small size and large imaging target surface, thereby broadening the application field of the telephoto lens, enabling the telephoto lens to match 1 / 2.7-inch chips, and meeting the requirements of low cost and high imaging quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a structural diagram of a telephoto lens provided by the utility model;

[0039] Figure 2 yes Figure 1 Schematic diagram of spherical aberration curve of telephoto lens shown;

[0040] Figure 3 This is a schematic structural diagram of another telephoto lens provided by the present invention;

[0041] Figure 4 yes Figure 3 Schematic diagram of spherical aberration curve of telephoto lens shown;

[0042] Figure 5 This is a structural diagram of another telephoto lens provided by the present invention;

[0043] Figure 6 yes Figure 5 Schematic diagram of the spherical aberration curve of the telephoto lens shown. DETAILED DESCRIPTION

[0044] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be fully described below in conjunction with the drawings in the embodiments of the present invention through specific implementation methods. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Various modifications and changes can be made in the present invention without departing from the spirit or scope of the present invention, which is obvious to those skilled in the art. Therefore, the present invention is intended to cover modifications and changes of the present invention that fall within the scope of the corresponding claims (technical solutions claimed for protection) and their equivalents.

[0045] Furthermore, the words “first”, “second” and similar terms used in the embodiments of the present disclosure do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as “one”, “an” or “the” do not indicate a quantity limitation, but rather indicate the existence of at least one. Words such as “include” or “comprise” mean that the elements or objects preceding the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as “connect” or “connected” are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. “Up”, “down”, “left”, “right” and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly. In addition, descriptions such as “same” and “equal” involved in the embodiments of the present disclosure do not mean that the two objects are exactly the same in size or shape. Approximately the same or approximately equal within a certain error range is allowed.

[0046] It should be noted that the implementation methods provided in the embodiments of the present invention can be combined with each other if there is no contradiction.

[0047] Figure 1 Schematic diagram of the structure of a telephoto lens provided by an embodiment of the present invention. Figure 1 As shown, the telephoto lens 100 includes: a first lens 10, a second lens 20, a third lens 30, a fourth lens 40, a fifth lens 50, a sixth lens 60, and a seventh lens 70, arranged in sequence along the optical axis from the object side to the image side. The first lens 10 is a glass spherical lens with positive optical power; the second lens 20 is a plastic aspherical lens with negative optical power; the third lens 30 is a glass spherical lens with positive optical power; the fourth lens 40 is a glass spherical lens with optical power; the fifth lens 50 is a plastic aspherical lens with negative optical power; the sixth lens 60 is a plastic aspherical lens with positive optical power; and the seventh lens 70 is a plastic aspherical lens with positive optical power. The total optical system length TTL of the telephoto lens 100 satisfies the relationship between the total optical system length TTL and the imaging target surface IMH: TTL / IMH≤3.2.

[0048] It can be understood that the optical power is equal to the difference between the convergence of the image-side beam and the convergence of the object-side beam, and it characterizes the ability of an optical system to deflect light. The larger the absolute value of the optical power, the stronger the ability to bend light, and the smaller the absolute value of the optical power, the weaker the ability to bend light. When the optical power is a positive number, the refraction of light is convergent; when the optical power is a negative number, the refraction of light is divergent. The optical power can be used to characterize a certain refractive surface of a lens (i.e., a surface of a lens), can be used to characterize a certain lens, and can also be used to characterize a system formed by multiple lenses (i.e., a lens group).

[0049] In this embodiment, each lens from the first lens 10 to the seventh lens 70 can be fixed to a lens barrel ( Figure 1 (not shown in the figure), by setting the first lens 10 to have a positive optical power, the light entering the optical system of the telephoto lens 100 can be converged, which is beneficial to the long focal length of the optical system of the telephoto lens 100; the second lens 20 is set to have a negative optical power, the third lens 30 is set to have a positive optical power, and the fourth lens 40 is set to have a positive optical power or a negative optical power, so that the light entering the telephoto lens 100 can smoothly transition between the lenses, which is beneficial to reducing the introduction of high-order spherical aberration and correcting system chromatic aberration, thereby improving the imaging clarity of the telephoto system.

[0050] It is also understood that the material of the glass spherical lens can be various types of glass known to those skilled in the art, and this embodiment of the present invention does not elaborate on or limit this. Due to the characteristics of glass spherical lenses, such as good surface finish, good light reflectivity, high impact strength, and stable chemical properties, they are suitable for use in high and low temperature environments. The material of the aspherical plastic lens can be various types of plastic known to those skilled in the art, and this embodiment of the present invention does not elaborate on or limit this. Plastic aspherical lenses have the characteristics of being lightweight, low cost, easy to process, and capable of correcting aberrations such as field curvature, astigmatism, spherical aberration, and coma.

[0051] In this embodiment, by configuring the first lens 10, the third lens 30, and the fourth lens 40 as glass spherical lenses, and configuring the second lens 20, the fifth lens 50, the sixth lens 60, and the seventh lens 70 as plastic spherical lenses, the telephoto lens 100 has a 3G4P structure. This allows the telephoto lens 100 to meet the requirements of use in high and low temperature environments while maintaining low mass and low cost, and to achieve high imaging clarity.

[0052] In addition, by setting the total optical system length TTL and the imaging target surface IMH of the telephoto lens 100 to satisfy: TTL / IMH≤3.2, for example, the total optical system length TTL can be no greater than 22.4 mm, and the imaging target surface IMH can be greater than 7 mm. This ensures that the telephoto lens 100 has a longer total optical system length while having a larger imaging target surface, which can be compatible with a 1 / 2.7-inch chip, meeting the requirements of high imaging quality and small size.

[0053] Optionally, the optical power of the first lens 10 satisfies the following relationship: 0.44 ≤ Φ1 / Φ ≤ 0.686, where Φ1 is the optical power of the first lens 10, and Φ is the optical power of the telephoto lens 100. Thus, by properly setting the optical power range of the first lens 10, light entering the optical system of the telephoto lens 100 can be converged, thereby facilitating achieving a long focal length of the optical system of the telephoto lens 100.

[0054] Optionally, the optical focal lengths of the second lens 20, the third lens 30, and the fourth lens 40 satisfy the following: -0.993≤Φ2 / Φ≤-0.60; 0.331≤Φ3 / Φ≤0.652; -0.701≤Φ4 / Φ≤0.14; Φ2 is the optical focal length of the second lens 20, Φ3 is the optical focal length of the third lens 30, Φ4 is the optical focal length of the fourth lens 40, and Φ is the optical focal length of the telephoto lens 100.

[0055] Optionally, the refractive index and Abbe number of the third lens 30 and the fourth lens 40 satisfy the following conditions: 1.41≤Nd3≤1.59; 57.07≤Vd3≤100.03; 1.78≤Nd4≤1.85; 25≤Vd4≤49; wherein Nd3 is the refractive index of the third lens 30, Vd3 is the Abbe number of the third lens 30, Nd4 is the refractive index of the fourth lens 40, and Vd4 is the Abbe number of the fourth lens 40.

[0056] In this embodiment, by properly setting the optical power ranges of the second, third, and fourth lenses, as well as properly setting the refractive indices and Abbe numbers of the third and fourth lenses, the amount of high-order spherical aberration introduced can be reduced, and system chromatic aberration can be corrected, thereby facilitating high-definition imaging and enabling the telephoto lens 100 to have a shorter overall optical system length.

[0057] Optionally, the second lens 20 is a convex-concave lens. This configuration allows the light passing through the first lens 10 to smoothly enter the second lens 20, which is beneficial to correcting system aberrations.

[0058] Optionally, the third lens 30 is a biconvex lens. This configuration allows light passing through the second lens 20 to enter the third lens 30 as much as possible, which is beneficial for reducing high-order spherical aberration of the optical system of the telephoto lens 100.

[0059] Optionally, the optical powers of the fifth lens 50, the sixth lens 60, and the seventh lens 70 satisfy the following conditions: -1.231≤Φ5 / Φ≤-0.545; 0.232≤Φ6 / Φ≤0.92; and 0.326≤Φ7 / Φ≤1.291, where Φ5 is the optical power of the fifth lens, Φ6 is the optical power of the sixth lens 60, Φ7 is the optical power of the seventh lens 70, and Φ is the optical power of the telephoto lens 100. Optionally, the fifth lens 50 is a meniscus lens, and the seventh lens 70 is a convexo-convex lens.

[0060] In this embodiment, by rationally setting the optical power ranges of the fifth, sixth, and seventh lenses, as well as the shapes of the fifth and seventh lenses, the angle of light rays reaching the image plane can be reduced, ensuring a high relative illumination of the imaged image, and facilitating aberration correction to ensure a high resolution.

[0061] Optionally, the telephoto lens further includes an aperture, which is located on the object side of the second lens 20. The aperture can limit the light beam, thereby improving the imaging quality.

[0062] Optionally, the third lens 30 and the fourth lens 40 form a cemented lens.

[0063] Optionally, the object-side surface of the first lens 10 is a convex surface. In this case, the image-side surface of the first lens 10 can be a concave surface, a convex surface or a flat surface, and can be designed according to actual needs. This embodiment of the utility model does not specifically limit this.

[0064] Optionally, the object-side surface of the fourth lens 40 is a concave surface. In this case, the image-side surface of the fourth lens 40 can be a concave surface, a convex surface or a flat surface, and can be designed according to actual needs. This embodiment of the utility model does not specifically limit this.

[0065] Optionally, the object-side surface of the sixth lens 60 is a convex surface, and the image-side surface of the sixth lens 60 can be a convex surface or a flat surface, which can be designed according to actual needs and is not specifically limited in the embodiment of the present invention.

[0066] In summary, the embodiment of the present invention adopts seven lenses with optical power to form a telephoto lens, and through the reasonable allocation of the optical power of each lens, and the reasonable selection of materials and shape design of each lens, the telephoto lens can achieve a smaller total optical system length, a larger light throughput, a lower cost, a larger imaging target area, and excellent imaging quality.

[0067] Specific embodiments of the telephoto lens applicable to the above-mentioned embodiments will be further described below with reference to the accompanying drawings.

[0068] In a feasible embodiment, Table 1 details the following in a feasible implementation manner: Figure 1 The specific optical and physical parameters of the telephoto lens are shown.

[0069] Table 1 Optical physical parameter design of a telephoto lens

[0070] Scope of protection Example 1 Lower limit Upper limit Φ1 / Φ 0.584 0.440 0.686 Φ2 / Φ -0.769 -0.993 -0.600 Φ3 / Φ 0.468 0.331 0.652 Φ4 / Φ -0.26 -0.701 0.146 Φ5 / Φ -0.603 -1.231 -0.545 Φ6 / Φ 0.29 0.232 0.920 Φ7 / Φ 1.06 0.326 1.291 Nd3 1.58 1.41 1.59 Nd4 1.79 1.78 1.85 Vd3 94.9 57.07 100.63 Vd4 36.5 25 49

[0071] The focal length f of the telephoto lens of this embodiment is 11.482 mm, the aperture number F is 1.31, and the corresponding angle when the imaging target surface IMH is 7 mm is 34°.

[0072] Table 2 shows the design parameters of the surface type, curvature radius, thickness, and material of each lens in a telephoto lens corresponding to Table 1.

[0073] Table 2 Parameter design of each lens in the telephoto lens

[0074]

[0075] The telephoto lens of this embodiment includes a first lens 10 , a second lens 20 , a third lens 30 , a fourth lens 40 , a fifth lens 50 , a sixth lens 60 , a seventh lens 70 and a flat glass 80 , which are arranged in sequence along the optical axis from the object side to the image side. Among them, the surface numbers are numbered according to the order of the surfaces of each lens. For example, the surface number "OBJ" represents the object surface of the telephoto lens, the surface number "S1" represents the object side surface of the first lens 10, and the surface number "S2" represents the image side surface of the first lens 10. And so on. "STO" represents the aperture stop and "IMA" represents the image surface of the telephoto lens. The radius of curvature represents the degree of curvature of the lens surface. A positive value represents that the surface is curved toward the object side with the center close to the image plane, while a negative value represents that the surface is curved toward the image side with the center close to the object plane. "Infinity" represents that the surface is flat and the radius of curvature is infinite. The thickness represents the axial distance from the center of the current surface to the next surface. The refractive index (Nd) represents the light deflection ability of the material between the current surface and the next surface. A blank space represents that the current position is air with a refractive index of 1. The Abbe number (Vd) represents the dispersion characteristics of the material between the current surface and the next surface. A blank space represents that the current position is air. The semi-aperture represents the effective diameter of the lens. The k value represents the numerical value of the conic coefficient of the aspheric surface.

[0076] The aspheric cone coefficient of the telephoto lens of this embodiment can be defined by the following aspheric formula, but is not limited to the following expression method:

[0077]

[0078] Wherein, z is the axial sagittal height in the Z direction of the aspheric surface, r is the height of the aspheric surface, c is the curvature of the fitting sphere, k is the cone coefficient, and A, B, C, D, E, and F correspond to the coefficients of the fourth-order, sixth-order, eighth-order, tenth-order, twelfth-order, and fourteenth-order terms of the aspheric polynomial, respectively.

[0079] Table 3 Aspheric coefficients of a telephoto lens

[0080]

[0081] Among them, -2.09659E-03 means that the coefficient A of the surface number S3 is -2.09659×10 -3 .

[0082] Figure 2 yes Figure 1 The schematic diagram of the spherical aberration curve of the telephoto lens is shown in Figure 2 The spherical aberration curve shown in the figure, the vertical direction represents the normalization of the aperture, 0 represents the optical axis, the vertical vertex represents the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focus, the unit is millimeter (mm). The different linear curves in the figure represent different wavelengths of system imaging, which are represented by Figure 2 It can be seen that the axial aberrations at different wavelengths (436nm, 486nm, 546nm, 588nm, 656nm, and 850nm) are all controlled within the range of (-0.05mm, +0.05mm), indicating that the spherical aberration of this telephoto lens at each wavelength is well controlled and can meet the needs of wide-spectrum applications.

[0083] In another possible embodiment, Figure 3 is a schematic diagram of the structure of another telephoto lens provided by an embodiment of the present invention. Table 4 describes in detail another feasible implementation method. Figure 3 The specific optical and physical parameters of the telephoto lens are shown.

[0084] Table 4 Another optical and physical parameter design of telephoto lens

[0085] Scope of protection Example 2 Lower limit Upper limit Φ1 / Φ 0.461 0.440 0.686 Φ2 / Φ -0.633 -0.993 -0.600 Φ3 / Φ 0.626 0.331 0.652 Φ4 / Φ -0.631 -0.701 0.146 Φ5 / Φ -1.174 -1.231 -0.545 Φ6 / Φ 0.677 0.232 0.920 Φ7 / Φ 1.211 0.326 1.291 Nd3 1.49 1.41 1.59 Nd4 1.84 1.78 1.85 Vd3 60.7 57.07 100.63 Vd4 47 25 49

[0086] The focal length f of the telephoto lens of this embodiment is 11.469 mm, the aperture number F is 1.60, and the corresponding angle when the imaging target surface IMH is 7 mm is 34°.

[0087] Table 5 shows the design parameters of the surface type, curvature radius, thickness, material, etc. of each lens in another telephoto lens corresponding to Table 4.

[0088] Table 5 Another parameter design of each lens in the telephoto lens

[0089]

[0090] The telephoto lens of this embodiment includes a first lens 10 , a second lens 20 , a third lens 30 , a fourth lens 40 , a fifth lens 50 , a sixth lens 60 , a seventh lens 70 and a flat glass 80 , which are arranged in sequence along the optical axis from the object side to the image side. Among them, the surface numbers are numbered according to the order of the surfaces of each lens. For example, the surface number "OBJ" represents the object surface of the telephoto lens, the surface number "S1" represents the object side surface of the first lens 10, and the surface number "S2" represents the image side surface of the first lens 10. And so on. "STO" represents the aperture stop and "IMA" represents the image surface of the telephoto lens. The radius of curvature represents the degree of curvature of the lens surface. A positive value represents that the surface is curved toward the object side with the center close to the image plane, while a negative value represents that the surface is curved toward the image side with the center close to the object plane. "Infinity" represents that the surface is flat and the radius of curvature is infinite. The thickness represents the axial distance from the center of the current surface to the next surface. The refractive index (Nd) represents the light deflection ability of the material between the current surface and the next surface. A blank space represents that the current position is air with a refractive index of 1. The Abbe number (Vd) represents the dispersion characteristics of the material between the current surface and the next surface. A blank space represents that the current position is air. The semi-aperture represents the effective diameter of the lens. The k value represents the numerical value of the conic coefficient of the aspheric surface.

[0091] The aspheric cone coefficient of the telephoto lens in this embodiment can be defined by the following aspheric formula, but is not limited to the following expression method:

[0092]

[0093] Wherein, z is the axial sagittal height in the Z direction of the aspheric surface, r is the height of the aspheric surface, c is the curvature of the fitting sphere, k is the cone coefficient, and A, B, C, D, E, and F correspond to the coefficients of the fourth-order, sixth-order, eighth-order, tenth-order, twelfth-order, and fourteenth-order terms of the aspheric polynomial, respectively.

[0094] Table 6 Aspheric coefficients of another telephoto lens

[0095]

[0096] Among them, -1.64338E-03 means that the coefficient A of the surface number S3 is -1.64338×10 -3 .

[0097] Figure 4 yes Figure 3 The schematic diagram of the spherical aberration curve of the telephoto lens is shown in Figure 4 The spherical aberration curve shown in the figure, the vertical direction represents the normalization of the aperture, 0 represents the optical axis, the vertical vertex represents the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focus, the unit is millimeter (mm). The different linear curves in the figure represent different wavelengths of system imaging, which are represented by Figure 4It can be seen that the axial aberrations at different wavelengths (436nm, 486nm, 546nm, 588nm, 656nm, and 850nm) are all controlled within the range of (-0.05mm, +0.05mm), indicating that the spherical aberration of this telephoto lens at each wavelength is well controlled and can meet the needs of wide-spectrum applications.

[0098] In another possible embodiment, Figure 5 This is a schematic diagram of the structure of another telephoto lens provided by an embodiment of the present invention. Table 7 describes in detail another feasible implementation method. Figure 5 The specific optical and physical parameters of the telephoto lens are shown.

[0099] Table 7 Another optical physical parameter design of telephoto lens

[0100] Scope of protection Example 3 Lower limit Upper limit Φ1 / Φ 0.666 0.440 0.686 Φ2 / Φ -0.961 -0.993 -0.600 Φ3 / Φ 0.358 0.331 0.652 Φ4 / Φ 0.076 -0.701 0.146 Φ5 / Φ -0.787 -1.231 -0.545 Φ6 / Φ 0.863 0.232 0.920 Φ7 / Φ 0.407 0.326 1.291 Nd3 1.43 1.41 1.59 Nd4 1.84 1.78 1.85 Vd3 97 57.07 100.63 Vd4 27 25 49

[0101] The focal length f of the telephoto lens of this embodiment is 11.694 mm, the aperture number F is 1.60, and the corresponding angle when the imaging target surface IMH is 7 mm is 34°.

[0102] Table 8 shows the design parameters of the surface type, curvature radius, thickness, material, etc. of each lens in another telephoto lens corresponding to Table 7.

[0103] Table 8 Another parameter design of each lens in the telephoto lens

[0104]

[0105] The telephoto lens of this embodiment includes a first lens 10 , a second lens 20 , a third lens 30 , a fourth lens 40 , a fifth lens 50 , a sixth lens 60 , a seventh lens 70 and a flat glass 80 , which are arranged in sequence along the optical axis from the object side to the image side. Among them, the surface numbers are numbered according to the order of the surfaces of each lens. For example, the surface number "OBJ" represents the object surface of the telephoto lens, the surface number "S1" represents the object side surface of the first lens 10, and the surface number "S2" represents the image side surface of the first lens 10. And so on. "STO" represents the aperture stop and "IMA" represents the image surface of the telephoto lens. The radius of curvature represents the degree of curvature of the lens surface. A positive value represents that the surface is curved toward the object side with the center close to the image plane, while a negative value represents that the surface is curved toward the image side with the center close to the object plane. "Infinity" represents that the surface is flat and the radius of curvature is infinite. The thickness represents the axial distance from the center of the current surface to the next surface. The refractive index (Nd) represents the light deflection ability of the material between the current surface and the next surface. A blank space represents that the current position is air with a refractive index of 1. The Abbe number (Vd) represents the dispersion characteristics of the material between the current surface and the next surface. A blank space represents that the current position is air. The semi-aperture represents the effective diameter of the lens. The k value represents the numerical value of the conic coefficient of the aspheric surface.

[0106] The aspheric cone coefficient of the telephoto lens in this embodiment can be defined by the following aspheric formula, but is not limited to the following expression method:

[0107]

[0108] Wherein, z is the axial sagittal height in the Z direction of the aspheric surface, r is the height of the aspheric surface, c is the curvature of the fitting sphere, k is the cone coefficient, and A, B, C, D, E, and F correspond to the coefficients of the fourth-order, sixth-order, eighth-order, tenth-order, twelfth-order, and fourteenth-order terms of the aspheric polynomial, respectively.

[0109] Table 9 Aspheric coefficients of another telephoto lens

[0110]

[0111] Among them, -2.59171E-03 means that the coefficient A of the surface number S3 is -2.59171×10 -3 .

[0112] Figure 6 yes Figure 5 The schematic diagram of the spherical aberration curve of the telephoto lens is shown in Figure 6 The spherical aberration curve shown in the figure, the vertical direction represents the normalization of the aperture, 0 represents the optical axis, the vertical vertex represents the maximum pupil radius; the horizontal direction represents the offset relative to the ideal focus, the unit is millimeter (mm). The different linear curves in the figure represent different wavelengths of system imaging, which are represented by Figure 6It can be seen that the axial aberrations at different wavelengths (436nm, 486nm, 546nm, 588nm, 656nm, and 850nm) are all controlled within the range of (-0.05mm, +0.05mm), indicating that the spherical aberration of this telephoto lens at each wavelength is well controlled and can meet the needs of wide-spectrum applications.

[0113] Note that the above are merely preferred embodiments of the present invention and the technical principles employed. Those skilled in the art will appreciate that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments, and substitutions are possible for those skilled in the art without departing from the scope of protection of the present invention. Therefore, while the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments and may include many other equivalent embodiments without departing from the scope of the present invention. The scope of the present invention is determined by the scope of the appended claims.

Claims

1. A telephoto lens, characterized in that: include: A first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens are arranged in sequence along the optical axis from the object side to the image side; The first lens is a glass spherical lens with positive optical power; The second lens is a plastic aspheric lens with negative optical power; The third lens is a glass spherical lens with positive optical power; The fourth lens is a glass spherical lens with optical power; The fifth lens is a plastic aspherical lens with negative optical power; The sixth lens is a plastic aspheric lens with positive optical power; The seventh lens is a plastic aspherical lens with positive optical power; The total length TTL of the optical system of the telephoto lens and the imaging target surface IMH satisfy the following relationship: TTL / IMH≤3.

2.

2. The telephoto lens according to claim 1, wherein: The optical power of the first lens satisfies: 0.44≤Φ1 / Φ≤0.686; Wherein, Φ1 is the optical focal length of the first lens, and Φ is the optical focal length of the telephoto lens.

3. The telephoto lens according to claim 1, wherein: The optical powers of the second lens, the third lens, and the fourth lens satisfy: -0.993≤Φ2 / Φ≤-0.60; 0.331≤Φ3 / Φ≤0.652; -0.701≤Φ4 / Φ≤0.14; Φ2 is the focal power of the second lens, Φ3 is the focal power of the third lens, Φ4 is the focal power of the fourth lens, and Φ is the focal power of the telephoto lens.

4. The telephoto lens according to claim 1, wherein: The refractive index and Abbe number of the third lens and the fourth lens satisfy: 1.41≤Nd3≤1.59; 57.07≤Vd3≤100.03; 1.78≤Nd4≤1.85; 25≤Vd4≤49; Wherein, Nd3 is the refractive index of the third lens, Vd3 is the Abbe number of the third lens, Nd4 is the refractive index of the fourth lens, and Vd4 is the Abbe number of the fourth lens.

5. The telephoto lens according to claim 1, wherein: The second lens is a convex-concave lens.

6. The telephoto lens according to claim 1, wherein: The third lens is a biconvex lens.

7. The telephoto lens according to claim 1, wherein: The optical powers of the fifth lens, the sixth lens, and the seventh lens satisfy: -1.231≤Φ5 / Φ≤-0.545; 0.232≤Φ6 / Φ≤0.92; 0.326≤Φ7 / Φ≤1.291; Φ5 is the optical power of the fifth lens, Φ6 is the optical power of the sixth lens, Φ7 is the optical power of the seventh lens, and Φ is the optical power of the telephoto lens.

8. The telephoto lens according to claim 1, wherein: The fifth lens is a meniscus lens.

9. The telephoto lens according to claim 1, wherein: The seventh lens is a convex-concave lens.

10. The telephoto lens according to claim 1, wherein: Also includes: Aperture; The aperture is located on the object side of the second lens.

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