Telephoto lens

Abstract

The invention provides a vehicle-mounted lens used in the technical field of vehicles, and particularly relates to a telephoto lens. From an object side to an imaging side, the telephoto lens sequentially comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens and an eighth lens which are sequentially arranged along the optical axis of the telephoto lens in the direction from the object side to the imaging side of the telephoto lens; wherein the first lens and the fourth lens have positive focal power, the first lens provides main focal power, and the third lens, the fifth lens and the eighth lens respectively have negative focal power; the second lens and the third lens are glued lenses, and the sixth lens and the seventh lens are glued lenses. According to the telephoto lens, through reasonably matching the first lens to the eighth lens, the imaging quality of the telephoto lens can be effectively improved, the cost is reduced, and the telephoto lens has a farther detection distance.

Description

Technical Field

[0001] The present application relates to the technical field of vehicle-mounted lenses, and in particular to a telephoto lens. Background Art

[0002] In recent years, with the rapid development of high-definition camera and vehicle-mounted module industries, the demand for forward-looking long-range vehicle-mounted lenses in vehicle-mounted modules has gradually increased, and the requirements for high imaging quality, high cost-effectiveness, and longer detection distance have become increasingly higher. Vehicles usually need to be equipped with long-focus lenses with large target areas, high imaging quality, and low costs. However, in the existing technology, the currently used long-focus lenses generally have problems such as small target areas, poor temperature control, and low resolution quality, which cannot meet the use requirements. Summary of the Invention

[0003] In view of this, the present application provides a telephoto lens, which, through the reasonable combination of the first lens to the eighth lens, can effectively improve the imaging quality of the telephoto lens, reduce the cost, and enable the telephoto lens to have a longer detection distance.

[0004] In order to achieve the above objectives, this application provides the following technical solutions:

[0005] A telephoto lens, comprising, from the object side to the imaging side, the following:

[0006] a first lens having positive optical power, wherein the first lens is a biconvex lens or a meniscus lens with a concave surface facing the imaging side, and the first lens provides the main optical power of the telephoto lens;

[0007] The second lens is a biconcave lens or a meniscus lens;

[0008] a third lens having negative optical power, wherein the third lens is a biconcave lens or a meniscus lens, and the second lens and the third lens are a cemented lens;

[0009] a fourth lens having positive optical power, wherein the fourth lens is a meniscus lens or a biconvex lens;

[0010] a fifth lens element having negative optical power, wherein the fifth lens element is a meniscus lens element with a concave surface facing the imaging side;

[0011] The sixth lens is a meniscus lens or a biconvex lens;

[0012] The seventh lens is a biconvex lens or a meniscus lens, and the sixth lens and the seventh lens are a cemented lens;

[0013] An eighth lens element having negative optical power is a meniscus lens element with a concave surface facing the imaging side.

[0014] The first and fourth lenses of the present application have positive focal power and the first lens provides the main focal power, and the third, fifth and eighth lenses respectively have negative focal power; the second and third lenses are cemented lenses, and the sixth and seventh lenses are cemented lenses; through the reasonable combination of positive and negative power lenses, and two groups of cemented lenses, the total optical length of the entire lens is reduced as much as possible; by setting the eighth lens as a meniscus lens with the concave surface facing the imaging side, the main light angle can be well controlled to achieve a perfect match with the sensor chip (imaging surface), thereby improving the chip compatibility of the lens, thereby effectively improving the imaging quality of the telephoto lens, reducing costs, and enabling the telephoto lens to have a longer detection distance.

[0015] Optionally, in embodiment 1 of the present application, both the object-side surface and the image-side surface of the first lens are convex along the optical axis;

[0016] The object-side surface and the image-side surface of the second lens are both concave along the optical axis;

[0017] The object-side surface of the third lens is convex along the optical axis, and the image-side surface of the third lens is concave along the optical axis;

[0018] The object-side surface of the fourth lens is convex along the optical axis, and the image-side surface of the fourth lens is concave along the optical axis;

[0019] The object-side surface of the fifth lens is convex along the optical axis, and the image-side surface of the fifth lens is concave along the optical axis;

[0020] The object-side surface of the sixth lens is convex along the optical axis, and the image-side surface of the sixth lens is concave along the optical axis;

[0021] The object-side surface and the image-side surface of the seventh lens are both convex along the optical axis;

[0022] An object-side surface of the eighth lens is concave along the optical axis, and an image-side surface of the eighth lens is convex along the optical axis.

[0023] In this embodiment, the first lens is a biconvex lens, the second lens is a biconcave lens, the third lens, the fourth lens, the fifth lens, and the sixth lens are meniscus lenses with the concave surface facing the imaging side, the seventh lens is a biconvex lens, and the eighth lens is a meniscus lens with the concave surface facing the object side. By rationally matching the lenses, the overall optical length of the lens is reduced, the imaging quality of the telephoto lens is improved, the cost is reduced, and the telephoto lens has a longer detection distance.

[0024] Optionally, in embodiment 2 of the present application, the object-side surface of the first lens is convex along the optical axis, and the image-side surface of the first lens is concave along the optical axis;

[0025] The object-side surface of the second lens is concave along the optical axis, and the image-side surface of the second lens is convex along the optical axis;

[0026] The object-side surface and the image-side surface of the third lens are both concave along the optical axis;

[0027] The object-side surface and the image-side surface of the fourth lens are both convex along the optical axis;

[0028] The object-side surface of the fifth lens is convex along the optical axis, and the image-side surface of the fifth lens is concave along the optical axis;

[0029] The object-side surface and the image-side surface of the sixth lens are both convex along the optical axis;

[0030] The object-side surface of the seventh lens is concave along the optical axis, and the image-side surface of the seventh lens is convex along the optical axis;

[0031] An object-side surface of the eighth lens is concave along the optical axis, and an image-side surface of the eighth lens is convex along the optical axis.

[0032] In this embodiment, the first lens is a meniscus lens with its concave surface facing the imaging side, the second lens is a meniscus lens with its concave surface facing the object side, the third lens is a biconcave lens, the fourth lens is a biconvex lens, the fifth lens is a meniscus lens with its concave surface facing the imaging side, the sixth lens is a biconvex lens, and the seventh and eighth lenses are meniscus lenses with their concave surfaces facing the object side. By reasonably matching the lenses, the overall optical length of the lens is reduced, the imaging quality of the telephoto lens is improved, the cost is reduced, and the telephoto lens has a longer detection distance.

[0033] Optionally, in embodiment 3 of the present application, the object-side surface of the first lens is convex along the optical axis, and the image-side surface of the first lens is concave along the optical axis;

[0034] The object-side surface of the second lens is convex along the optical axis, and the image-side surface of the second lens is concave along the optical axis;

[0035] The object-side surface of the third lens is convex along the optical axis, and the image-side surface of the third lens is concave along the optical axis;

[0036] The object-side surface of the fourth lens is convex along the optical axis, and the image-side surface of the fourth lens is concave along the optical axis;

[0037] The object-side surface of the fifth lens is convex along the optical axis, and the image-side surface of the fifth lens is concave along the optical axis;

[0038] The object-side surface of the sixth lens is convex along the optical axis, and the image-side surface of the sixth lens is concave along the optical axis;

[0039] The object-side surface and the image-side surface of the seventh lens are both convex along the optical axis;

[0040] An object-side surface of the eighth lens is concave along the optical axis, and an image-side surface of the eighth lens is convex along the optical axis.

[0041] In this embodiment, the first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens are meniscus lenses with the concave surface facing the imaging side, the seventh lens is a biconvex lens, and the eighth lens is a meniscus lens with the concave surface facing the object side. By rationally matching the lenses, the overall optical length of the lens is reduced, the imaging quality of the telephoto lens is improved, the cost is reduced, and the telephoto lens has a longer detection distance.

[0042] Optionally, the first lens, the second lens, the third lens, the fourth lens, the sixth lens and the seventh lens are glass spherical lenses; the fifth lens and the eighth lens are glass aspherical lenses, and an aperture is provided between the fourth lens and the fifth lens.

[0043] Glass spherical lenses have a long service life and stability, which effectively corrects the aberrations of the lens and has the advantage of small focus drift at high and low temperatures. They can adapt to different temperature environments and have good temperature control. Glass aspherical lenses can correct complex aberrations such as field curvature, coma, and astigmatism through surface optimization. The combination of glass spherical lenses and glass aspherical lenses can improve the imaging quality of telephoto lenses.

[0044] Optionally, the fifth lens and the eighth lens of the present application are both aspherical glass spherical lenses; in order to correct complex aberrations such as field curvature, coma, and astigmatism, the distances of the object-side surface and the image-side surface of the fifth lens (15) and the eighth lens (18) from the vertex of the curved surface in the optical axis direction are equal to the sum of the following items:

[0045] ① The reciprocal of the sum of the square root of the difference between the sum of 1 and the coefficient of the quadratic surface plus 1, the product of the square of the curvature of the vertex of the surface and the square of the distance from the optical axis to the surface, plus 1, and the product of the square of the distance from the optical axis to the surface and the curvature of the vertex of the surface;

[0046] ②The product of the fourth power of the distance from the optical axis to the curved surface and the fourth-order surface coefficient;

[0047] ③The product of the sixth power of the distance from the optical axis to the curved surface and the sixth-order curved surface coefficient;

[0048] ④The product of the eighth power of the distance from the optical axis to the curved surface and the eighth-order curved surface coefficient;

[0049] ⑤The product of the tenth power of the distance from the optical axis to the curved surface and the tenth-order curved surface coefficient;

[0050] That is, the surface shapes of the fifth lens and the eighth lens both satisfy the following equations:

[0051]

[0052] Where z is the distance of the surface from the vertex in the direction of the optical axis, c is the curvature of the vertex, K is the quadratic surface coefficient, h is the distance from the optical axis to the surface, and B, C, D, and E are the fourth-order, sixth-order, eighth-order, and tenth-order surface coefficients, respectively.

[0053] Optionally, a radius of curvature R9 of the object-side surface of the fifth lens is greater than 10°; and a chief ray angle CRA of the telephoto lens is greater than 10° and less than 20°.

[0054] That is, the telephoto lens satisfies: R9>10, and 10<CRA<20.

[0055] When a telephoto lens satisfies the above two relationships, in order to correct aberrations while changing the lens's chief ray angle as much as possible, the lens's chip compatibility is increased. That is, the number of optional chips is increased while ensuring that the chief ray angle is within the above range.

[0056] Optionally, the Abbe number V1 of the first lens is greater than 40; and

[0057] The ratio of the sum of the Abbe number V4 of the fourth lens element and the Abbe number V5 of the fifth lens element to the Abbe number V7 of the seventh lens element (V4+V5) / V7 is greater than 0.5; and

[0058] The difference between the curvature radius R1 of the first lens object side surface, the curvature radius R6 of the fourth lens object side surface and the curvature radius R 14 The ratio of (R1-R6) / R 14 Less than -0.1.

[0059] That is, the telephoto lens satisfies: V1>40; (V4+V5) / V7>0.5; and (R1-R6) / R 14 <-0.1;

[0060] When the telephoto lens satisfies the above three relationships, the intermediate lens group can provide the overall optical lens focal length while being able to achieve the day and night confocal function and to correct optical aberrations well.

[0061] Optionally, the curvature radius R5 of the imaging side surface of the third lens and the curvature radius R 13The ratio of the difference between the first lens element and the curvature radius R9 of the object side surface of the fifth lens (R5-R 13 ) / R9 is less than 4.

[0062] That is: the telephoto lens satisfies: (R5-R 13 ) / R9<4;

[0063] When the telephoto lens satisfies the above relationship, the distortion of the telephoto lens is well corrected, so that the imaging ratio of the lens is close to the actual ratio of the objective object.

[0064] Optionally, the optical power of the first lens is The optical power of the telephoto lens Ratio greater than 0.8 and less than 1.2; and / or,

[0065] The combined optical power of the second lens, the third lens, the fourth lens, and the fifth lens The optical power of the telephoto lens Ratio greater than -1.5 and less than -0.5; and / or,

[0066] The combined optical power of the sixth lens and the seventh lens The optical power of the telephoto lens Ratio greater than 0.3 and less than 0.8; and / or,

[0067] The optical power of the eighth lens The optical power of the telephoto lens Ratio Greater than -0.2 and less than 0.2.

[0068] That is, the telephoto lens satisfies: and / or, and / or, and / or,

[0069] To ensure that the telephoto lens has good enough imaging quality:

[0070] The main function of the first lens in a telephoto lens is to focus the light from the object with a wide field of view into the lens, while correcting the lens distortion without generating large aberrations. A reasonable ratio of can ensure that the optical power, total system length and spherical aberration of the telephoto lens remain in the optimal range;

[0071] The second lens, the third lens, the fourth lens, and the fifth lens constitute a lens group of the telephoto lens. The combined optical power of the lens group inherits the first lens mentioned above. A reasonable ratio can ensure that the total length of the telephoto lens system and spherical aberration, astigmatism, and field curvature remain in the optimal range;

[0072] The sixth lens and the seventh lens form the lens group of the telephoto lens, which effectively improves aberration and image quality. When the ratio exceeds a reasonable limit, the aberration correction ability of the lens group decreases;

[0073] The eighth lens, when When the ratio exceeds a reasonable limit, the lens's ability to control field curvature decreases. BRIEF DESCRIPTION OF THE DRAWINGS

[0074] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without any creative work.

[0075] Figure 1 Schematic diagram of a first embodiment of the telephoto lens of the present application;

[0076] Figure 2 This is a schematic diagram of imaging of the first embodiment of the telephoto lens of the present application;

[0077] Figure 3 This is a schematic diagram of imaging of the second embodiment of the telephoto lens of the present application;

[0078] Figure 4 This is a schematic diagram of imaging of Example 3 of the telephoto lens of the present application;

[0079] Figure 5 The defocus curve of the telephoto lens of Example 1 of the present application;

[0080] Figure 6 This is the defocus curve of Example 2 of the telephoto lens of the present application;

[0081] Figure 7 This is the defocus curve of Example 3 of the telephoto lens of the present application;

[0082] Figure 8 This is the MTF curve of Example 1 of the telephoto lens of the present application;

[0083] Figure 9 This is the MTF curve of Example 2 of the telephoto lens of the present application;

[0084] Figure 10 This is the MTF curve of Example 3 of the telephoto lens of the present application;

[0085] Figure 11 This is the illumination curve of Example 1 of the telephoto lens of the present application;

[0086] Figure 12 This is the illumination curve of Example 2 of the telephoto lens of the present application;

[0087] Figure 13 This is the illumination curve of Example 3 of the telephoto lens of the present application;

[0088] Figure 14 The chief ray angle curve of the telephoto lens of Example 1 of the present application;

[0089] Figure 15 This is the chief ray angle curve of Example 2 of the telephoto lens of the present application;

[0090] Figure 16 This is the chief ray angle curve of Example 3 of the telephoto lens of the present application;

[0091] Figure 17 Schematic diagram of the imaging point size of the first embodiment of the telephoto lens of the present application;

[0092] Figure 18 This is a schematic diagram of the imaging point size of the second embodiment of the telephoto lens of the present application;

[0093] Figure 19 Schematic diagram of the imaging point size of the third embodiment of the telephoto lens of the present application.

[0094] exist Figures 1-19 middle:

[0095] 11. First lens; 12. Second lens; 13. Third lens; 14. Fourth lens; 15. Fifth lens; 16. Sixth lens; 17. Seventh lens; 18. Eighth lens; 19. Aperture stop; 20. Visible light filter; 21. Cover glass; 22. Imaging surface. DETAILED DESCRIPTION

[0096] The present application provides a telephoto lens, which can effectively improve the imaging quality of the telephoto lens, reduce costs, and enable the telephoto lens to have a longer detection distance through the reasonable combination of the first lens to the eighth lens.

[0097] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0098] The present application provides a telephoto lens. The telephoto lens of the present application comprises, from the object side to the imaging side, the following components:

[0099] a first lens 11 having positive optical power, wherein the first lens 11 is a biconvex lens or a meniscus lens with a concave surface facing the imaging side, and provides the main optical power of the telephoto lens;

[0100] The second lens 12 is a biconcave lens or a meniscus lens;

[0101] a third lens 13 having negative optical power, wherein the third lens 13 is a biconcave lens or a meniscus lens, and the second lens 12 and the third lens 13 are a cemented lens;

[0102] a fourth lens element 14 having positive refractive power, wherein the fourth lens element 14 is a meniscus lens or a biconvex lens;

[0103] a fifth lens element 15 having negative optical power, wherein the fifth lens element 15 is a meniscus lens element with a concave surface facing the imaging side;

[0104] The sixth lens 16 is a meniscus lens or a biconvex lens;

[0105] The seventh lens 17 is a biconvex lens or a meniscus lens, and the sixth lens 16 and the seventh lens 17 are a cemented lens;

[0106] The eighth lens element 18 has negative refractive power and is a meniscus lens with a concave surface facing the imaging side.

[0107] The first lens 11 and the fourth lens 14 of the present application have positive optical power, wherein the first lens 11 provides the main optical power, converges the object plane light with a wide field of view angle into the lens, and corrects the lens distortion at the same time; the third lens 13, the fifth lens 15 and the eighth lens 18 have negative optical power respectively; the second lens 12 and the third lens 13 are cemented lenses, and the sixth lens 16 and the seventh lens 17 are cemented lenses; through the reasonable combination of each positive optical power and negative optical power lens, and the two groups of cemented lenses, the total optical length of the entire lens is reduced as much as possible; by setting the eighth lens 18 as a meniscus lens with the concave surface facing the imaging side, the main light angle can be well controlled to achieve a perfect match with the sensor chip (imaging surface 22), thereby improving the chip compatibility of the lens, thereby effectively improving the imaging quality of the telephoto lens, reducing costs, and enabling the telephoto lens to have a longer detection distance.

[0108] This application provides a preferred embodiment 1, such as Figure 1 and 2 As shown, the object-side surface and the image-side surface of the first lens 11 are both convex along the optical axis;

[0109] The object-side surface and the image-side surface of the second lens 12 are both concave along the optical axis;

[0110] The object-side surface of the third lens 13 is convex along the optical axis, and the image-side surface of the third lens 13 is concave along the optical axis;

[0111] The object-side surface of the fourth lens 14 is convex along the optical axis, and the image-side surface of the fourth lens 14 is concave along the optical axis;

[0112] The object-side surface of the fifth lens 15 is convex along the optical axis, and the image-side surface of the fifth lens 15 is concave along the optical axis;

[0113] The object-side surface of the sixth lens 16 is convex along the optical axis, and the image-side surface of the sixth lens 16 is concave along the optical axis;

[0114] The object-side surface and the image-side surface of the seventh lens 17 are both convex along the optical axis;

[0115] The object-side surface of the eighth lens 18 is concave along the optical axis, and the image-side surface of the eighth lens 18 is convex along the optical axis.

[0116] In the descriptions of the above lens shapes, the statement that one surface of the lens is convex along the optical axis means that the paraxial region of the corresponding surface is convex, and the statement that one surface of the lens is concave along the optical axis means that the paraxial region of the corresponding surface is concave. Therefore, even when one surface of the lens is described as convex, the edge portion of the one surface of the lens may be concave. Similarly, even when one surface of the lens is described as concave, the edge portion of the one surface of the lens may be convex, and the same applies hereinafter.

[0117] In the telephoto lens of this embodiment, the relevant parameters of each lens are shown in Table a1. Figure 5 The defocus curve of the telephoto lens in Example 1 is presented. Figure 8 The MTF curve of the telephoto lens in Example 1 is presented. Figure 11 The illumination curve of the telephoto lens in Example 1 is presented. Figure 14 The chief ray angle curve of the telephoto lens in Example 1 is presented; Figure 17 The imaging point size of the telephoto lens of this example is presented. As can be seen from the above figure, the telephoto lens of Example 1 has good optical performance and high imaging quality.

[0118] In this embodiment, the first lens 11 is a biconvex lens, the second lens 12 is a biconcave lens, the third lens 13, the fourth lens 14, the fifth lens 15, and the sixth lens 16 are meniscus lenses with the concave surface facing the imaging side, the seventh lens 17 is a biconvex lens, and the eighth lens 18 is a meniscus lens with the concave surface facing the object side. By rationally matching the lenses, the overall optical length of the lens is reduced, the imaging quality of the telephoto lens is improved, the cost is reduced, and the telephoto lens has a longer detection distance.

[0119] like Figure 3 As shown, the present application also provides a preferred embodiment 2. In this embodiment, the object-side surface of the first lens 11 is convex along the optical axis, and the image-side surface of the first lens 11 is concave along the optical axis;

[0120] The object-side surface of the second lens 12 is concave along the optical axis, and the image-side surface of the second lens 12 is convex along the optical axis;

[0121] The object-side surface and the image-side surface of the third lens 13 are both concave along the optical axis;

[0122] The object-side surface and the image-side surface of the fourth lens 14 are both convex along the optical axis;

[0123] The object-side surface of the fifth lens 15 is convex along the optical axis, and the image-side surface of the fifth lens 15 is concave along the optical axis;

[0124] The object-side surface and the image-side surface of the sixth lens 16 are both convex along the optical axis;

[0125] The object-side surface of the seventh lens element 17 is concave along the optical axis, and the image-side surface of the seventh lens element 17 is convex along the optical axis.

[0126] The object-side surface of the eighth lens 18 is concave along the optical axis, and the image-side surface of the eighth lens 18 is convex along the optical axis.

[0127] In the telephoto lens of this embodiment, the relevant parameters of each lens are shown in Table a2. Figure 6 The defocus curve of the telephoto lens in Example 2 is presented. Figure 9 The MTF curve of the telephoto lens in Example 2 is presented. Figure 12 The illumination curve of the telephoto lens in Example 2 is presented. Figure 15 The chief ray angle curve of the telephoto lens in Example 2 is presented; Figure 18 The imaging point size of the telephoto lens of this example is presented. As can be seen from the above figure, the telephoto lens of Example 2 has good optical performance and high imaging quality.

[0128] In this embodiment, the first lens 11 is a meniscus lens with its concave surface facing the imaging side, the second lens 12 is a meniscus lens with its concave surface facing the object side, the third lens 13 is a biconcave lens, the fourth lens 14 is a biconvex lens, the fifth lens 15 is a meniscus lens with its concave surface facing the imaging side, the sixth lens 16 is a biconvex lens, and the seventh lens 17 and the eighth lens 18 are meniscus lenses with their concave surfaces facing the object side. By reasonably matching the lenses, the total optical length of the entire lens is reduced, the imaging quality of the telephoto lens is improved, the cost is reduced, and the telephoto lens has a longer detection distance.

[0129] like Figure 4 As shown, the present application also provides a preferred embodiment 3. In this embodiment, the object-side surface of the first lens 11 is convex along the optical axis, and the image-side surface of the first lens 11 is concave along the optical axis;

[0130] The object-side surface of the second lens 12 is convex along the optical axis, and the image-side surface of the second lens 12 is concave along the optical axis;

[0131] The object-side surface of the third lens 13 is convex along the optical axis, and the image-side surface of the third lens 13 is concave along the optical axis;

[0132] The object-side surface of the fourth lens 14 is convex along the optical axis, and the image-side surface of the fourth lens 14 is concave along the optical axis;

[0133] The object-side surface of the fifth lens 15 is convex along the optical axis, and the image-side surface of the fifth lens 15 is concave along the optical axis;

[0134] The object-side surface of the sixth lens 16 is convex along the optical axis, and the image-side surface of the sixth lens 16 is concave along the optical axis;

[0135] The object-side surface and the image-side surface of the seventh lens 17 are both convex along the optical axis;

[0136] The object-side surface of the eighth lens 18 is concave along the optical axis, and the image-side surface of the eighth lens 18 is convex along the optical axis.

[0137] In the telephoto lens of this embodiment, the relevant parameters of each lens are shown in Table a3. Figure 7 The defocus curve of the telephoto lens in Example 3 is presented. Figure 10 The MTF curve of the telephoto lens in Example 3 is presented. Figure 13 The illumination curve of the telephoto lens in Example 3 is presented. Figure 16 The chief ray angle curve of the telephoto lens in Example 3 is presented; Figure 19 The imaging point size of the telephoto lens of this example is presented. As can be seen from the above figure, the telephoto lens of Example 3 has good optical performance and high imaging quality.

[0138] In this embodiment, the first lens 11, the second lens 12, the third lens 13, the fourth lens 14, the fifth lens 15 and the sixth lens 16 are meniscus lenses with the concave surface facing the imaging side, the seventh lens 17 is a biconvex lens, and the eighth lens 18 is a meniscus lens with the concave surface facing the object side. By rationally matching the lenses, the total optical length of the entire lens is reduced, the imaging quality of the telephoto lens is improved, the cost is reduced, and the telephoto lens has a longer detection distance.

[0139] In a preferred embodiment, Figure 1-4 As shown, the telephoto lens further includes an aperture 19 and a filter.

[0140] Aperture 19, which can be made of filter paper with a central aperture, is positioned between fourth lens element 14 and fifth lens element 15. Aperture 19 precisely adjusts the amount of light passing through. To capture clear images in dimly lit scenes, a lens with a large light flux is required. Placing aperture 19 at this location helps control the incident angle of the principal light beam reaching imaging surface 22, effectively keeping it within ±3 degrees, which better meets the incident angle requirements of the chip. Furthermore, aperture 19 is made of light-shielding paper with a central aperture. Using light-shielding paper as aperture 19 reduces the requirements for the lens barrel aperture, maximizing machining accuracy, reducing machining errors, and facilitating adjustment.

[0141] The optical filter is a visible light filter 20, which is disposed on the imaging side of the eighth lens element 18. When the visible light filter 20 is used, its thickness is preferably 0.5 mm. In this embodiment, a 0.5 mm thick visible light filter 20 is used as an example, but it is understood that the thickness of the visible light filter may be greater than this. Alternatively, if stray light caused by the visible light filter 20 is considered, the visible light filter 20 may be removed and the optical filter may be replaced with a visible light filter layer, which is coated on the object-side surface of the fourth lens element 14. By suppressing the transmission of light in non-operating wavelengths, the optical filter can effectively reduce chromatic aberration and stray light in the optical system, thereby improving imaging quality.

[0142] In a preferred embodiment, the first lens 11, the second lens 12, the third lens 13, the fourth lens 14, the sixth lens 16 and the seventh lens 17 are glass spherical lenses; the fifth lens 15 and the eighth lens 18 are glass aspherical lenses; and each lens of the telephoto lens is coated with a high-transmittance multilayer film.

[0143] Glass spherical lenses have a long service life and stability, effectively correcting lens aberrations and minimizing focus drift at high and low temperatures. They can adapt to different temperature environments and provide good temperature control. Glass aspherical lenses, on the other hand, can correct complex aberrations such as field curvature, coma, and astigmatism through surface optimization. The combination of glass spherical and glass aspherical lenses improves the imaging quality of telephoto lenses.

[0144] Specifically, the fifth lens element 15 near the center mainly eliminates spherical aberration and coma. Eliminating spherical aberration can eliminate the divergence of peripheral light and improve the resolution between the center and the edge; eliminating coma can suppress the comet-like smear formed by off-axis light.

[0145] The eighth lens 18 close to the imaging side mainly plays the role of eliminating field curvature and astigmatism. Eliminating field curvature can make the entire field of view focus on the same plane and avoid image bending; eliminating astigmatism can reduce the focusing difference of light in different directions and improve contrast.

[0146] In a preferred embodiment, the fifth lens element 15 and the eighth lens element 18 of the present application are both aspherical glass spherical lenses. To correct complex aberrations such as field curvature, coma, and astigmatism, the distances from the object-side and image-side surfaces of the fifth lens element 15 and the eighth lens element 18 to the vertex of the curved surface along the optical axis are equal to the sum of the following terms:

[0147] ① The reciprocal of the sum of the square root of the difference between the sum of 1 and the coefficient of the quadratic surface plus 1, the product of the square of the curvature of the vertex of the surface and the square of the distance from the optical axis to the surface, plus 1, and the product of the square of the distance from the optical axis to the surface and the curvature of the vertex of the surface;

[0148] ②The product of the fourth power of the distance from the optical axis to the curved surface and the fourth-order surface coefficient;

[0149] ③The product of the sixth power of the distance from the optical axis to the curved surface and the sixth-order curved surface coefficient;

[0150] ④The product of the eighth power of the distance from the optical axis to the curved surface and the eighth-order curved surface coefficient;

[0151] ⑤The product of the tenth power of the distance from the optical axis to the curved surface and the tenth-order curved surface coefficient;

[0152] That is, the surface shapes of the fifth lens 15 and the eighth lens 18 both satisfy the following equations:

[0153]

[0154] Where z is the distance of the surface from the vertex in the direction of the optical axis, c is the curvature of the vertex, K is the quadratic surface coefficient, h is the distance from the optical axis to the surface, and B, C, D, and E are the fourth-order, sixth-order, eighth-order, and tenth-order surface coefficients, respectively.

[0155] Table b1, Table b2 and Table b3 are the relevant parameters of the fifth lens 15 and the eighth lens 18 in Example 1, Example 2 and Example 3 respectively.

[0156] In a preferred embodiment, the curvature radius R9 of the object-side surface of the fifth lens element 15 is greater than 10°; and the chief ray angle CRA of the telephoto lens is greater than 10° and less than 20°.

[0157] That is to say: the telephoto lens satisfies: R9>10, and 10<CRA<20.

[0158] The chief ray angle (CRA) refers to the maximum angle of incidence of the chief ray (the light passing through the center of the aperture 19) when it enters the sensor. It directly affects the illumination uniformity and color consistency at the edge of the sensor.

[0159] The radius of curvature R9 of the object-side surface of the fifth lens element 15 directly affects the path of light refraction, correcting aberrations such as field curvature and astigmatism. It also indirectly affects CRA by adjusting the curvature to change the direction of the light path.

[0160] When a telephoto lens satisfies the above two relationships, fine adjustment of the aspheric curvature radius of the fifth lens element 15, combined with optimization of the position of the aperture 19 and coordinated aberration correction, allows for flexible control of the CRA without significantly sacrificing optical performance, thereby improving the lens' compatibility with different sensor chips. This, in turn, increases the number of selectable chips while ensuring that the chief ray angle is within the above range.

[0161] In a preferred embodiment, the Abbe number V1 of the first lens 11 is greater than 40; and

[0162] The ratio (V4+V5) / V7 of the sum of the Abbe number V4 of the fourth lens element 14 and the Abbe number V5 of the fifth lens element 15 to the Abbe number V7 of the seventh lens element 17 is greater than 0.5; and

[0163] The difference between the curvature radius R1 of the object side surface of the first lens 11 and the curvature radius R6 of the object side surface of the fourth lens 14 and the curvature radius R 14 The ratio of (R1-R6) / R 14 Less than -0.1.

[0164] That is, the telephoto lens satisfies: V1>40; (V4+V5) / V7>0.5; (R1-R6) / R 14 <-0.1;

[0165] The combination of lenses made of low-dispersion materials (high Abbe numbers) and high-dispersion materials (low Abbe numbers) can offset focal length differences between light of different wavelengths. The design of the curvature radius of the aspheric lenses (corresponding to the corresponding relationship between the curvature radii of the first lens element 11, the seventh lens element 17, and the eighth lens element 18 in this embodiment) allows marginal light in the visible and infrared bands to focus on the same plane, thereby suppressing defocus caused by dispersion. In this embodiment, the first lens element 11 is made of low-dispersion material. Working in conjunction with the intermediate lens group (the fourth lens element 14, the fifth lens element 15, and the seventh lens element 17), it not only provides the overall optical power of the optical lens, but also effectively achieves daytime and nighttime confocality. Furthermore, the corresponding relationship between the curvature radii of the first lens element 11, the seventh lens element 17, and the eighth lens element 18 allows for excellent correction of optical aberrations, ensuring sufficiently good nighttime imaging quality.

[0166] In a preferred embodiment, the curvature radius R5 of the imaging side surface of the third lens 13 and the curvature radius R 13 The ratio of the difference between the first and second lens elements 15 and the curvature radius R9 of the object side surface of the fifth lens element 15 (R5-R 13 ) / R9 is less than 4.

[0167] That is: the telephoto lens meets: (R5-R 13 ) / R9<4.

[0168] When a telephoto lens satisfies the above relationship, the curvature gradient of the aspheric surface is strictly limited, and high-order aberrations are effectively suppressed, thereby achieving the following effects: Distortion correction: pincushion / barrel distortion is reduced to <0.5%, so that the imaging ratio of the lens is close to the actual ratio of the objective object, and the imaging ratio error is <0.5%; Image quality improvement: The MTF value is increased by 20%-30%, and the edge resolution is significantly improved; Compatibility enhancement: Adaptation to a variety of sensor chips reduces the burden of subsequent algorithm correction.

[0169] In a preferred embodiment, the optical power of the first lens 11 is The focal length of a telephoto lens Ratio greater than 0.8 and less than 1.2; and / or,

[0170] Combined optical power of the second lens 12, the third lens 13, the fourth lens 14 and the fifth lens 15 The focal length of a telephoto lens Ratio greater than -1.5 and less than -0.5; and / or,

[0171] Combined optical power of the sixth lens 16 and the seventh lens 17 The focal length of a telephoto lens Ratio greater than 0.3 and less than 0.8; and / or,

[0172] Refractive power of the eighth lens 18 The focal length of a telephoto lens Ratio Greater than -0.2 and less than 0.2.

[0173] That is: a telephoto lens satisfies: and / or, and / or, and / or,

[0174] To ensure that the telephoto lens has sufficiently good imaging quality, the following are required:

[0175] The main function of the first lens 11 in the telephoto lens is to focus the object light with a wide field of view into the lens, and at the same time correct the lens distortion without generating large aberrations. When the value exceeds the upper limit, the focal length of the lens is too strong. Although it can reduce the total length of the system, the spherical aberration it produces is too large and difficult to correct. When the value exceeds the lower limit, the focal power of the lens is weakened and the spherical aberration is relatively reduced, but its refractive power decreases, resulting in a longer total length of the system.

[0176] The second lens 12, the third lens 13, the fourth lens 14, and the fifth lens 15 form a lens group of the telephoto lens. The combined optical power of the lens group inherits the first lens 11 mentioned above and effectively cooperates with the first lens 11. When the value exceeds the upper limit, the total length of the system can be reduced, but the spherical aberration, astigmatism, and field curvature it produces are too large and difficult to correct; when When the value exceeds the lower limit, the optical power of the lens group is weakened, and the above-mentioned aberrations are relatively reduced, but its refractive power decreases, resulting in a longer system.

[0177] The sixth lens 16 and the seventh lens 17 form a lens group of the telephoto lens, which effectively improves aberration and enhances imaging quality. When the value exceeds the limit, the aberration correction capability of the lens group decreases.

[0178] The eighth lens 18, when When the value exceeds the limit, the lens's ability to control field curvature decreases.

[0179] In a preferred embodiment, the value of the full field angle 2θ of the telephoto lens is greater than 20° and less than 40°.

[0180] That is to say: the telephoto lens satisfies: 20°<2θ<40°;

[0181] When the above conditions are met, the telephoto lens can cover medium and long-distance targets, taking into account both field of view and details.

[0182] In a preferred embodiment, the aperture number F# of the telephoto lens is greater than 1.4 and less than 1.8.

[0183] That is: the telephoto lens meets: 1.4 <F#<1.8;

[0184] When the aperture number of the telephoto lens exceeds the upper limit, the remaining margin of correctable aberration of the entire lens is too large, and the cost can be reduced by reducing the number of lenses. When the aperture number exceeds the lower limit, the aberration of the entire lens is too large, and the imaging quality of the entire lens can be improved by increasing the number of lenses. In this embodiment, under the premise that the number of lenses is determined to be 8, it is more reasonable to set the aperture number between 1.4 and 1.8.

[0185] In a preferred embodiment, the value of the illumination RI of the telephoto lens is greater than 90%.

[0186] That is to say: telephoto lens meets: RI>90%;

[0187] When the illumination exceeds the lower limit, the illumination of the entire lens is too low, which can easily affect the imaging brightness at the edge position and reduce the imaging quality.

[0188] In a preferred embodiment, the total optical length of the telephoto lens is T L The ratio T to the image height h of the telephoto lens L / h is greater than 4 and less than 5.

[0189] To limit the total length of the lens and ensure that the lens has good enough imaging quality, the telephoto lens meets the following requirements: <T L / h<5;

[0190] When T L When the value of / h exceeds the upper limit, the overall length of the lens is too long, or if the overall length is shortened, the image height will be insufficient; when T L When the value of / h exceeds the lower limit, the optical focal length of each lens is too large, lens aberration correction is difficult, and the resolving power is significantly reduced.

[0191] In a preferred embodiment, a ratio SD1 / h of the semi-aperture SD1 of the first lens 11 to the image plane height h of the telephoto lens is greater than 1 and less than 1.5.

[0192] In order to provide a suitable lens size while having good aberration correction, the telephoto lens should meet the following requirements: 1. <SD1 / h<1.5;

[0193] The first lens 11 mainly plays the role of collecting light in the telephoto lens, and the larger the overall outer diameter, the better the light collecting effect, but it increases the overall size of the lens. After many experiments, it was found that when the above relationship is satisfied, the good light collecting effect of the lens can be guaranteed while the overall size of the lens can be guaranteed.

[0194] In the telephoto lens of this example, the relevant parameters of each lens are shown in Table a1, Table a2, Table a3, Table b1, Table b2, and Table b3. L It is the distance measured based on the optical axis of the lens.

[0195] Table a1:

[0196]

[0197]

[0198] Table b1:

[0199]

[0200] Table a2:

[0201]

[0202] Table b2:

[0203]

[0204] Table a3:

[0205]

[0206] Table b3:

[0207] Surface serial number K B C D E S9 -2.04E+01 -7.40E-05 -7.12E-07 1.81E-08 1.70E-10 S10 1.50E+00 -2.97E-04 3.23E-06 -1.03E-07 2.62E-09 S14 -1.13E+00 7.00E-05 8.08E-08 1.50E-08 -3.91E-10 S15 -2.00E+02 -1.05E-04 -7.21E-07 1.68E-08 -3.82E-10

[0208] Table 2 shows the optical characteristics of each of the three embodiments above, including focal length f, aperture number F#, and total system length T. L and the full field angle 2θ, and also includes the relevant values ​​corresponding to each of the above relationship expressions.

[0209] Table 2:

[0210]

[0211] It can be seen from the above table that in Example 1:

[0212] The object-side surface curvature radius R9 of the fifth lens element 15 is 14.504, and the chief ray angle CRA of the telephoto lens is 17.5°, satisfying the conditions of R9>10 and 10<CRA<20, which can improve the compatibility of the lens with different sensor chips.

[0213] The Abbe number V1 of the first lens 11 is 64.800, the ratio of the sum of the Abbe number V4 of the fourth lens 14 and the Abbe number V5 of the fifth lens 15 to the Abbe number V7 of the seventh lens 17 is (V4+V5) / V7=0.870, the difference between the curvature radius R1 of the object side surface of the first lens 11 and the curvature radius R6 of the object side surface of the fourth lens 14 and the curvature radius R 14 The ratio of (R1-R6) / R 14 =-0.357, satisfying V1>40; and (V4+V5) / V7>0.5; and (R1-R6) / R 14 <-0.1, it can well complete the day and night confocal function, and can well correct optical aberrations, ensuring that the lens has sufficiently good night imaging quality;

[0214] The curvature radius R5 of the imaging side surface of the third lens 13 and the curvature radius R 13 The ratio of the difference between the first and second lens elements 15 and the curvature radius R9 of the object side surface of the fifth lens element 15 (R5-R 13 ) / R9=2.779, satisfying (R5-R 13 ) / R9<4, the curvature gradient of the aspheric surface is strictly limited, and high-order aberrations are effectively suppressed;

[0215] satisfy The conditions control the total length of the lens system and improve the imaging quality;

[0216] The full field of view of the telephoto lens is 2θ = 33°, which satisfies the condition of 20° < 2θ < 40°. The telephoto lens can cover medium and long-range targets, taking into account both vision and details.

[0217] The aperture number F# of the telephoto lens is 1.600, which satisfies the condition of 1.4 < F# < 1.8, keeping the correctable aberration of the overall lens within a reasonable range;

[0218] The illuminance RI of the telephoto lens is 1.000, which satisfies the condition of RI > 90%, and it is not easy to affect the imaging brightness at the edge position;

[0219] The overall optical length T of the telephoto lens L The ratio T of the overall optical length of the telephoto lens to the image height h of the telephoto lens L / h = 4.942, which satisfies the condition of 4 < T L / h < 5, restricting the overall length of the lens and ensuring good imaging quality of the lens;

[0220] The ratio SD1 / h of the semi-aperture SD1 of the first lens 11 to the image height h of the telephoto lens is 1.359, which satisfies the condition of 1 < SD1 / h < 1.5, enabling the telephoto lens to provide a suitable lens size while correcting aberration well;

[0221] The above effects can be verified from Figure 5 , Figure 8 , Figure 11 , Figure 14 and Figure 17 the data in:

[0222] As Figure 5 shown by the defocus curve, the curves at each field of view are very concentrated and the defocus is small;

[0223] As Figure 8 shown, the MTF curves at each field of view decrease smoothly, and the MTF value at the central field of view reaches 0.64 at 150 cycles / mm, and the MTF value at the edge field of view is greater than 0.55, indicating good imaging effect and resolution of the lens;

[0224] As Figure 11 shown, the illuminance RI at each field of view is greater than 90%, and it is not easy to affect the imaging brightness at the edge position;

[0225] As Figure 14 shown, the telephoto lens can well control the chief ray angle CRA to match the sensor chip, improving the compatibility of the lens with the sensor chip;

[0226] As Figure 17 shown, the image height of the telephoto lens can match the image height of the imaging surface;

[0227] In the second embodiment:

[0228] The radius of curvature R9 of the object side surface of the fifth lens 15 is 28.027, and the chief ray angle CRA of the telephoto lens is 17.9°. Meeting the conditions of R9 > 10 and 10 < CRA < 20 can improve the compatibility of the lens with different sensor chips;

[0229] The Abbe number V1 of the first lens 11 is 52.300, and the ratio (V4 + V5) / V7 of the sum of the Abbe numbers V4 of the fourth lens 14 and V5 of the fifth lens 15 to the Abbe number V7 of the seventh lens 17 is 2.856. The difference between the radius of curvature R1 of the object side surface of the first lens 11 and the radius of curvature R6 of the object side surface of the fourth lens 14 and the radius of curvature R 14 of the object side surface of the eighth lens 18 is in the ratio (R1 - R6) / R 14 = -0.565. Meeting the conditions of V1 > 40; (V4 + V5) / V7 > 0.5; and (R1 - R6) / R 14 < -0.1 can well complete the function of day and night confocal, and can well correct optical aberrations, ensuring that the lens has good enough night imaging quality;

[0230] The difference between the radius of curvature R5 of the image side surface of the third lens 13 and the radius of curvature R 13 of the image side surface of the seventh lens 17 and the ratio (R5 - R 13 ) / R9 of the radius of curvature R9 of the object side surface of the fifth lens 15 is 1.518. Meeting the condition of (R5 - R 13 ) / R9 < 4 strictly limits the curvature gradient of the aspherical surface and effectively suppresses high-order aberrations;

[0231] Meeting the conditions controls the overall length of the lens system and improves the imaging quality;

[0232] The full field angle 2θ of the telephoto lens is 35°. Meeting the condition of 20° < 2θ < 40°, the telephoto lens can cover medium and long-distance targets, taking into account both the field of view and details;

[0233] The aperture number F# of the telephoto lens is 1.600. Meeting the condition of 1.4 < F# < 1.8 keeps the correctable aberrations of the overall lens within a reasonable range;

[0234] The illuminance RI of the telephoto lens is 1.000. Meeting the condition of RI > 90% is not likely to affect the imaging brightness at the edge position;

[0235] The ratio T L of the optical total length T of the telephoto lens to the image height h of the telephoto lens is T L / h = 4.699. Meeting the condition of 4 < T LUnder the condition of / h < 5, the total length of the lens is limited, and the lens has sufficiently good imaging quality;

[0236] The ratio SD1 / h of the semi-aperture SD1 of the first lens 11 to the image plane height h of the telephoto lens is SD1 / h = 1.260, which satisfies the condition of 1 < SD1 / h < 1.5, enabling the telephoto lens to provide a suitable lens size while well correcting aberrations;

[0237] The above effects can be verified from Figure 6 , Figure 9 , Figure 12 , Figure 15 and Figure 18 the data in:

[0238] As Figure 6 shown by the defocus curve, the curves under each field of view are very concentrated and the defocus is small;

[0239] As Figure 9 shown, the MTF curves under each field of view decline smoothly, and the MTF value of the central field of view reaches 0.60 at 150 cycles / mm, and the MTF value of the marginal field of view is greater than 0.58, indicating that the imaging effect and resolution of this lens are good;

[0240] As Figure 12 shown, the illuminance RI under each field of view is greater than 90%, and it is not easy to affect the imaging brightness at the edge position;

[0241] As Figure 15 shown, the telephoto lens can well control the chief ray angle CRA to match it with the sensor chip, improving the compatibility of the lens with the sensor chip;

[0242] As Figure 18 shown, the image height of the telephoto lens can match the image plane height;

[0243] In Embodiment 3:

[0244] The radius of curvature R9 of the object side surface of the fifth lens 15 is R9 = 23.513, and the chief ray angle CRA of the telephoto lens is 16.3°, which satisfies the conditions of R9 > 10 and 10 < CRA < 20, and can improve the compatibility of the lens with different sensor chips;

[0245] The Abbe number V1 of the first lens 11, the ratio (V4 + V5) / V7 of the sum of the Abbe numbers V4 of the fourth lens 14 and V5 of the fifth lens 15 to the Abbe number V7 of the seventh lens 17, the difference between the radius of curvature R1 of the object side surface of the first lens 11 and the radius of curvature R6 of the object side surface of the fourth lens 14 and the radius of curvature R 14 of the object side surface of the eighth lens 18 14= -0.216, satisfying V1 > 40; and (V4 + V5) / V7 > 0.5; and (R1 - R6) / R 14 < -0.1, can well complete the function of day and night confocal, and can well correct optical aberrations, ensuring that the lens has good enough night imaging quality;

[0246] The radius of curvature R5 of the imaging side surface of the third lens 13, the radius of curvature R 13 of the imaging side surface of the seventh lens 17, and the ratio (R5 - R 13 ) / R9 of the difference to the radius of curvature R9 of the object side surface of the fifth lens 15 is 1.699, satisfying the condition (R5 - R 13 ) / R9 < 4, the curvature gradient of the aspherical surface is strictly restricted, and high-order aberrations are effectively suppressed;

[0247] Satisfying the condition, controls the overall length of the lens system and improves the imaging quality;

[0248] The full field angle 2θ of the telephoto lens is 35°, satisfying the condition 20° < 2θ < 40°, and the telephoto lens can cover medium and long distance targets, taking into account both the field of view and details;

[0249] The aperture number F# of the telephoto lens is 1.600, satisfying the condition 1.4 < F# < 1.8, keeping the correctable aberrations of the overall lens within a reasonable range;

[0250] The illuminance RI of the telephoto lens is 1.000, satisfying the condition RI > 90%, and it is not easy to affect the imaging brightness at the edge position;

[0251] The optical overall length T L of the telephoto lens and the ratio T L / h of the telephoto lens to the image plane height h is 4.430, satisfying the condition 4 < T L / h < 5, the overall length of the lens is restricted, and the lens has good enough imaging quality;

[0252] The ratio SD1 / h of the semi-aperture SD1 of the first lens 11 to the image plane height h of the telephoto lens is 1.287, satisfying the condition 1 < SD1 / h < 1.5, enabling the telephoto lens to provide a suitable lens size while well correcting aberrations;

[0253] The above effects can be verified from Figure 7 、 Figure 10 、 Figure 13 、 Figure 16 and Figure 19 the data in:

[0254] Such as Figure 7 The defocus curves shown show that the curves under each field of view are very concentrated and the defocus is small;

[0255] like Figure 10 As shown in the figure, the MTF curves under each field of view all decrease smoothly, and the MTF value of the central field of view reaches 0.59 at 150 cycles / mm, and the MTF value of the edge field of view is greater than 0.58. The imaging effect and resolution of this lens are good;

[0256] like Figure 13 As shown in the figure, the illuminance RI under each field of view is greater than 90%, which is not likely to affect the imaging brightness at the edge position;

[0257] like Figure 16 As shown in the figure, the telephoto lens can well control the chief ray angle (CRA) to match it with the sensor chip, improving the sensor chip compatibility of the lens;

[0258] like Figure 19 As shown, the image height of a telephoto lens can match the height of the imaging surface.

[0259] The basic principles of the present application have been described above in conjunction with specific embodiments. However, it should be noted that the advantages, strengths, and effects mentioned in this application are merely illustrative and not restrictive, and it should not be assumed that these advantages, strengths, and effects are required of each embodiment of this application. In addition, the specific details disclosed above are merely illustrative and facilitating understanding, and are not restrictive. The above details do not limit this application to necessarily being implemented using the above specific details.

[0260] The block diagrams of the devices, devices, equipment, and systems involved in this application are merely illustrative examples and are not intended to require or imply that they must be connected, arranged, or configured in the manner shown in the block diagrams. As will be appreciated by those skilled in the art, these devices, devices, equipment, and systems can be connected, arranged, or configured in any manner. Words such as "include," "comprise," "have," and the like are open-ended words, meaning "including but not limited to," and can be used interchangeably therewith. The words "or" and "and" used herein refer to the word "or" and can be used interchangeably therewith, unless the context clearly indicates otherwise. The word "such as" used herein refers to the phrase "such as but not limited to," and can be used interchangeably therewith.

[0261] It should also be noted that in the apparatus, device, and method of the present application, each component or each step can be decomposed or recombined, and such decomposition or recombination should be regarded as equivalent solutions of the present application.

[0262] The above description of the disclosed aspects is provided to enable any person skilled in the art to make or use the present application. Various modifications to these aspects will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other aspects without departing from the scope of the present application. Therefore, the present application is not intended to be limited to the aspects shown herein, but rather to be accorded the widest scope consistent with the principles and novel features disclosed herein.

[0263] It should be understood that the qualifiers "first", "second", "third", "fourth", "fifth" and "sixth" used in the description of the embodiments of the present application are only used to more clearly illustrate the technical solutions and cannot be used to limit the scope of protection of the present application.

[0264] The above description has been provided for the purpose of illustration and description. Furthermore, this description is not intended to limit the embodiments of the present application to the forms disclosed herein. Although a number of example aspects and embodiments have been discussed above, those skilled in the art will recognize certain variations, modifications, alterations, additions, and sub-combinations thereof.

Claims

1. A telephoto lens, characterized in that: From the object side to the imaging side, it includes: a first lens (11) having positive optical power, wherein the first lens (11) is a biconvex lens or a meniscus lens with a concave surface facing the imaging side, and the first lens (11) provides the main optical power of the telephoto lens; The second lens (12) is a biconcave lens or a meniscus lens; a third lens (13) having negative optical power, wherein the third lens (13) is a biconcave lens or a meniscus lens, and the second lens (12) and the third lens (13) are a cemented lens; a fourth lens (14) having positive optical power, wherein the fourth lens (14) is a meniscus lens or a biconvex lens; a fifth lens (15) having negative optical power, wherein the fifth lens (15) is a meniscus lens with a concave surface facing the imaging side; The sixth lens (16) is a meniscus lens or a biconvex lens; The seventh lens (17) is a biconvex lens or a meniscus lens, and the sixth lens (16) and the seventh lens (17) are a cemented lens; An eighth lens (18) with negative optical power is provided, wherein the eighth lens (18) is a meniscus lens with a concave surface facing the imaging side.

2. The telephoto lens according to claim 1, wherein: The object side surface and the image side surface of the first lens (11) are both convex along the optical axis; The object side surface and the image side surface of the second lens (12) are both concave along the optical axis; The object-side surface of the third lens (13) is convex along the optical axis, and the imaging-side surface of the third lens (13) is concave along the optical axis; The object-side surface of the fourth lens (14) is convex along the optical axis, and the image-side surface of the fourth lens (14) is concave along the optical axis; The object-side surface of the fifth lens (15) is convex along the optical axis, and the image-side surface of the fifth lens (15) is concave along the optical axis; The object-side surface of the sixth lens (16) is convex along the optical axis, and the image-side surface of the sixth lens (16) is concave along the optical axis; The object side surface and the image side surface of the seventh lens (17) are both convex along the optical axis; The object-side surface of the eighth lens (18) is concave along the optical axis, and the image-side surface of the eighth lens (18) is convex along the optical axis.

3. The telephoto lens according to claim 1, wherein: The object-side surface of the first lens (11) is convex along the optical axis, and the imaging-side surface of the first lens (11) is concave along the optical axis; The object side surface of the second lens (12) is concave along the optical axis, and the imaging side surface of the second lens (12) is convex along the optical axis; The object side surface and the image side surface of the third lens (13) are both concave along the optical axis; The object side surface and the image side surface of the fourth lens (14) are both convex along the optical axis; The object-side surface of the fifth lens (15) is convex along the optical axis, and the image-side surface of the fifth lens (15) is concave along the optical axis; The object side surface and the image side surface of the sixth lens (16) are both convex along the optical axis; The object-side surface of the seventh lens (17) is concave along the optical axis, and the image-side surface of the seventh lens (17) is convex along the optical axis; The object-side surface of the eighth lens (18) is concave along the optical axis, and the image-side surface of the eighth lens (18) is convex along the optical axis.

4. The telephoto lens according to claim 1, wherein: The object-side surface of the first lens (11) is convex along the optical axis, and the imaging-side surface of the first lens (11) is concave along the optical axis; The object-side surface of the second lens (12) is convex along the optical axis, and the imaging-side surface of the second lens (12) is concave along the optical axis; The object-side surface of the third lens (13) is convex along the optical axis, and the imaging-side surface of the third lens (13) is concave along the optical axis; The object-side surface of the fourth lens (14) is convex along the optical axis, and the image-side surface of the fourth lens (14) is concave along the optical axis; The object-side surface of the fifth lens (15) is convex along the optical axis, and the image-side surface of the fifth lens (15) is concave along the optical axis; The object-side surface of the sixth lens (16) is convex along the optical axis, and the image-side surface of the sixth lens (16) is concave along the optical axis; The object side surface and the image side surface of the seventh lens (17) are both convex along the optical axis; The object-side surface of the eighth lens (18) is concave along the optical axis, and the image-side surface of the eighth lens (18) is convex along the optical axis.

5. The telephoto lens according to any one of claims 1 to 4, wherein: The first lens (11), the second lens (12), the third lens (13), the fourth lens (14), the sixth lens (16) and the seventh lens (17) are glass spherical lenses; the fifth lens (15) and the eighth lens (18) are glass aspherical lenses; and a stop (19) is provided between the fourth lens (14) and the fifth lens (15).

6. The telephoto lens according to claim 5, wherein: The distances between the object-side surface and the image-side surface of the fifth lens (15) and the eighth lens (18) and the vertex of the curved surface in the optical axis direction are equal to the sum of the following items: ① The reciprocal of the sum of the square root of the difference between the sum of 1 and the coefficient of the quadratic surface plus 1, the product of the square of the curvature of the vertex of the surface and the square of the distance from the optical axis to the surface, plus 1, and the product of the square of the distance from the optical axis to the surface and the curvature of the vertex of the surface; ②The product of the fourth power of the distance from the optical axis to the curved surface and the fourth-order curved surface coefficient; ③The product of the sixth power of the distance from the optical axis to the curved surface and the sixth-order curved surface coefficient; ④The product of the eighth power of the distance from the optical axis to the curved surface and the eighth-order curved surface coefficient; ⑤ The product of the tenth power of the distance from the optical axis to the curved surface and the tenth-order curved surface coefficient.

7. The telephoto lens according to claim 6, wherein: The curvature radius R9 of the object side surface of the fifth lens (15) is greater than 10°; and the chief ray angle CRA of the telephoto lens is greater than 10° and less than 20°.

8. The telephoto lens according to claim 6, wherein: The Abbe number V1 of the first lens (11) is greater than 40; and The ratio (V4+V5) / V7 of the sum of the Abbe number V4 of the fourth lens (14), the Abbe number V5 of the fifth lens (15) and the Abbe number V7 of the seventh lens (17) is greater than 0.5; and The difference between the curvature radius R1 of the object side surface of the first lens (11), the curvature radius R6 of the object side surface of the fourth lens (14), and the curvature radius R of the object side surface of the eighth lens (18) is 14 The ratio of (R1-R6) / R 14 Less than -0.

1.

9. The telephoto lens according to claim 6, wherein: The curvature radius R5 of the imaging side surface of the third lens (13) and the curvature radius R 13 The ratio of the difference between the first and second lens elements (15) and the curvature radius R9 of the object side surface of the fifth lens (15) (R5-R 13 ) / R9 is less than 4.

10. The telephoto lens according to claim 6, wherein: The focal power of the first lens (11) The optical power of the telephoto lens Ratio greater than 0.8 and less than 1.2; and / or, The combined optical power of the second lens (12), the third lens (13), the fourth lens (14) and the fifth lens (15) The optical power of the telephoto lens Ratio greater than -1.5 and less than -0.5; and / or, The combined optical power of the sixth lens (16) and the seventh lens (17) The optical power of the telephoto lens Ratio greater than 0.3 and less than 0.8; and / or, The optical power of the eighth lens (18) The optical power of the telephoto lens Ratio Greater than -0.2 and less than 0.2.

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