Large-aperture double-telecentric lens

Abstract

The utility model discloses a large-aperture double-telecentric lens. A first light path part, an aperture diaphragm and a second light path part are sequentially arranged from an object side to an image side along the optical axis of the lens; the first optical path part sequentially comprises a first glass lens with positive focal power, a second glass lens with positive focal power, a third glass lens with negative focal power, a fourth glass lens with positive focal power, a fifth glass lens with negative focal power and a sixth glass lens with negative focal power; and the second optical path part sequentially comprises a seventh glass lens with positive focal power, an eighth glass lens with negative focal power, a ninth glass lens with positive focal power and a tenth glass lens with positive focal power. According to the utility model, the ten spherical glass lenses are adopted, and the focal power of each lens and the shape of each lens surface are reasonably configured, so that the optical system can be ensured to have good distortion correction, and meanwhile, the advantages of large aperture, low distortion, high resolution and the like are realized.

Description

Technical Field

[0001] The utility model relates to the technical field of optical lenses, and particularly relates to a large-aperture double telecentric lens. Background Art

[0002] In recent years, with the rapid development of the machine vision industry in various fields, vision systems with high resolution, large field of view, and high processing speed have emerged continuously, which puts forward higher requirements for the supporting optical lenses. Among them, the telecentric lens is mainly a specially designed lens to correct the parallax of traditional industrial lenses. It can make the magnification of the obtained image not change with the change of the object distance within the depth of field. The telecentric lens has characteristics such as small distortion, large depth of field, and good uniformity. Therefore, the telecentric lens is favored by various machine vision applications. The application range of the existing telecentric lens is limited. On the one hand, the aperture of the telecentric lens with small magnification and large target surface is small, and the object-side resolution is low. On the other hand, the field of view of the telecentric lens with large magnification is small. Content of the Utility Model

[0003] Aiming at the deficiencies in the prior art, the purpose of the utility model is to provide a large-aperture double telecentric lens, which adopts 10 spherical glass lenses, the total length of the lens is < 255 mm, the aperture F# ≥ 2.8, the magnification is 0.1×, and the entrance pupil diameter is 150 mm, meeting the requirements of optical detection.

[0004] The purpose of the utility model is achieved through the following technical solutions:

[0005] A large-aperture double telecentric lens, defining the surface of the lens adjacent to the object side as the object side surface, and the surface of the lens adjacent to the image side as the image side surface. A first optical path part and a second optical path part are sequentially arranged along the optical axis of the lens from the object side to the image side;

[0006] The first optical path part is sequentially arranged along the optical axis of the lens from the object side to the image side:

[0007] The first lens, the first lens is a glass lens with positive optical power, the object side surface of the first lens is convex, and the image side surface is concave;

[0008] The second lens, the second lens is a glass lens with positive optical power, the object side surface of the second lens is convex, and the image side surface is concave;

[0009] The third lens, the third lens is a glass lens with negative optical power, the object side surface of the third lens is convex, and the image side surface is concave;

[0010] The fourth lens, the fourth lens is a glass lens with positive optical power, the object side surface of the fourth lens is convex, and the image side surface is concave;

[0011] The fifth lens, the fifth lens is a glass lens with a negative optical power, the object side of the fifth lens is convex, and the image side is concave;

[0012] The sixth lens, the sixth lens is a glass lens with a negative optical power, the object side of the sixth lens is convex, and the image side is concave;

[0013] The second optical path part is arranged in sequence from the object side to the image side along the lens optical axis:

[0014] The seventh lens, the seventh lens is a glass lens with a positive optical power, the object side of the seventh lens is convex, and the image side is convex;

[0015] The eighth lens, the eighth lens is a glass lens with a negative optical power, the object side of the eighth lens is concave, and the image side is concave;

[0016] The ninth lens, the ninth lens is a glass lens with a positive optical power, the object side of the ninth lens is convex, and the image side is convex;

[0017] The tenth lens, the tenth lens is a glass lens with a positive optical power, the object side of the tenth lens is convex, and the image side is convex;

[0018] It further includes:

[0019] An aperture stop, the aperture stop is located on the object side of the seventh lens;

[0020] An image acquisition element, the image acquisition element is arranged on the image side of the tenth lens.

[0021] Further, the lens satisfies the following relational expressions:

[0022] The lens satisfies the following relational expressions:

[0023] F#≥2.8,

[0024] TTL≤255mm,

[0025] f≥420.033mm,

[0026] OBFL≥21.605mm,

[0027] IC / TTL≥0.05,

[0028] TTL / f≤0.6,

[0029] OBFL / TTL≥0.07,

[0030] In the relational expression, F# is the aperture of the lens, f is the total focal length of the lens, TTL is the total optical length of the lens, OBFL is the optical back focal length of the lens, and IC is the full image height of the chip matched with the lens system.

[0031] Furthermore, the lens also satisfies the following relational expression:

[0032] 0.65 ≤ f1 / f ≤ 0.73

[0033] 0.32 ≤ f2 / f ≤ 0.33,

[0034] -0.34 ≤ f3 / f ≤ -0.32,

[0035] 0.24 ≤ f4 / f ≤ 0.25,

[0036] -0.06 ≤ f5 / f ≤ -0.04,

[0037] -0.10 ≤ f6 / f ≤ -0.08,

[0038] 0.05 ≤ f7 / f ≤ 0.06,

[0039] -0.06 ≤ f8 / f ≤ -0.05,

[0040] 0.06 ≤ f9 / f ≤ 0.08,

[0041] 0.09 ≤ f10 / f ≤ 0.10,

[0042] In the relational expression, f is the total focal length of the lens, f1 is the focal length of the first lens, f2 is the focal length of the second lens, f3 is the focal length of the third lens, f4 is the focal length of the fourth lens, f5 is the focal length of the fifth lens, f6 is the focal length of the sixth lens, f7 is the focal length of the seventh lens, f8 is the focal length of the eighth lens, f9 is the focal length of the ninth lens, and f10 is the focal length of the tenth lens.

[0043] Furthermore, the focal lengths, refractive indices, and curvature radii of the first lens, second lens, third lens, fourth lens, fifth lens, sixth lens, seventh lens, eighth lens, ninth lens, and tenth lens respectively satisfy the following conditions:

[0044]

[0045]

[0046] Wherein, f1 is the focal length of the first lens, ND1 is the refractive index of the first lens, R11 is the curvature radius of the object side surface of the first lens, and R12 is the curvature radius of the image side surface of the first lens; f2 is the focal length of the second lens, ND2 is the refractive index of the second lens, R21 is the curvature radius of the object side surface of the second lens, and R22 is the curvature radius of the image side surface of the second lens; f3 is the focal length of the third lens, ND3 is the refractive index of the third lens, R31 is the curvature radius of the object side surface of the third lens, and R32 is the curvature radius of the image side surface of the third lens; f4 is the focal length of the fourth lens, ND4 is the refractive index of the fourth lens, R41 is the curvature radius of the object side surface of the fourth lens, and R42 is the curvature radius of the image side surface of the fourth lens; f5 is the focal length of the fifth lens, ND5 is the refractive index of the fifth lens, R51 is the curvature radius of the object side surface of the fifth lens, and R52 is the curvature radius of the image side surface of the fifth lens; f6 is the focal length of the sixth lens, ND6 is the refractive index of the sixth lens, R61 is the curvature radius of the object side surface of the sixth lens, and R62 is the curvature radius of the image side surface of the sixth lens; f7 is the focal length of the seventh lens, ND7 is the refractive index of the seventh lens, R71 is the curvature radius of the object side surface of the seventh lens, and R72 is the curvature radius of the image side surface of the seventh lens; f8 is the focal length of the eighth lens, ND8 is the refractive index of the eighth lens, R81 is the curvature radius of the object side surface of the eighth lens, and R82 is the curvature radius of the image side surface of the eighth lens; f9 is the focal length of the ninth lens, ND9 is the refractive index of the ninth lens, R91 is the curvature radius of the object side surface of the ninth lens, and R92 is the curvature radius of the image side surface of the ninth lens; f10 is the focal length of the tenth lens, ND10 is the refractive index of the tenth lens, R101 is the curvature radius of the object side surface of the tenth lens, and R102 is the curvature radius of the image side surface of the tenth lens;

[0047] Focal length: The "+" sign indicates that the lens has a positive optical power, and the "-" sign indicates that the lens has a negative optical power. The unit of the focal length is mm;

[0048] Radius of curvature: The "+" sign indicates that the surface bends towards the image side, and the "-" sign indicates that the surface bends towards the object side. The unit is mm.

[0049] The beneficial effects of the present utility model are:

[0050] The lens of the present utility model adopts ten lenses with specific optical powers. Through specific surface shape matching and reasonable optical power distribution, the structure of the lens is more compact. Compared with the existing lenses on the market, the aperture F# satisfies F#≥2.8, which can ensure a large amount of incident light; it has the characteristics of double telecentric and high resolution, and is suitable for measuring the size of workpieces in industrial inspection;

[0051] In terms of manufacturability, ten spherical glass lenses are adopted. The thickness of each lens is uniform, reasonable and insensitive, which is easy to manufacture and has a high yield rate. Description of the Drawings

[0052] Figure 1 Schematic diagram of the optical structure of Embodiment 1 of the present utility model;

[0053] Figure 2 Schematic diagram of the optical path structure of Embodiment 1 of the present utility model;

[0054] Figure 3 Field curvature curve graph and distortion curve graph of visible light of 0.486 - 0.656μm in Embodiment 1 of the present utility model;

[0055] Figure 4 MTF curve at 125 lp / mm under visible light in Embodiment 1 of the present utility model;

[0056] Figure 5 Schematic diagram of the optical structure of Embodiment 2 of the present utility model;

[0057] Figure 6 Schematic diagram of the optical path structure of Embodiment 2 of the present utility model;

[0058] Figure 7 Field curvature curve graph and distortion curve graph of visible light of 0.486 - 0.656μm in Embodiment 2 of the present utility model;

[0059] Figure 8 MTF curve at 125 lp / mm under visible light in Embodiment 2 of the present utility model;

[0060] Reference numerals: 1 - first lens, 2 - second lens, 3 - third lens, 4 - fourth lens, 5 - fifth lens, 6 - sixth lens, 7 - seventh lens, 8 - eighth lens, 9 - ninth lens, 10 - tenth lens, 12 - aperture stop, 13 - image acquisition element. Detailed implementation manners

[0061] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all of the embodiments. In this specification, the expressions such as first, second, and third are only used to distinguish one feature from another feature, and do not represent any limitation on the features. The shapes of the spherical or aspherical surfaces are not limited to the spherical or aspherical shapes shown in the drawings. The drawings are only for illustration and are not drawn strictly to scale.

[0062] In the present utility model, the paraxial region refers to the region near the optical axis. If the lens surface is convex and the position of the convex surface is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the position of the concave surface is not defined, it means that the lens surface is concave at least in the paraxial region; if the lens surface is not defined as convex, concave or flat, it means that the lens surface can be convex, concave or flat. The surface of each lens closest to the object being photographed is called the object side surface of the lens, and the surface of each lens closest to the imaging surface is called the image side surface of the lens.

[0063] Unless otherwise defined, all terms (including technical and scientific terms) used in the present utility model shall have the same meaning as commonly understood by those of ordinary skill in the art to which this application belongs. It should also be understood that terms (such as those defined in a common dictionary) should be interpreted as having a meaning consistent with their meaning in the context of the relevant art, and will not be interpreted in an idealized or overly formal sense unless explicitly defined as such in the present utility model.

[0064] It should be noted that, without conflict, the embodiments in this application and the features in the embodiments can be combined with each other. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model. For better understanding and implementation, the present utility model will be described in detail below with reference to the accompanying drawings.

[0065] The present utility model provides a large aperture double telecentric lens. The surface of the lens adjacent to the object side is the object side surface, and the surface of the lens adjacent to the image side is the image side surface. Along the optical axis of the lens, a first lens 1, a second lens 2, a third lens 3, a fourth lens 4, a fifth lens 5, a sixth lens 6, an aperture stop 12, a seventh lens 7, an eighth lens 8, a ninth lens 9, a tenth lens 10, and an image acquisition element 13 are sequentially arranged from the object side to the image side. Among them, the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5, and the sixth lens 6 form a first optical path part, the seventh lens 7, the eighth lens 8, the ninth lens 9, and the tenth lens 10 form a second optical path part, the aperture stop is located on the object side surface of the seventh lens, and the image acquisition element is arranged on the image side surface of the tenth lens.

[0066] Wherein:

[0067] The first lens 1 is a glass lens with positive optical power, its object side surface is convex, and its image side surface is concave;

[0068] The second lens 2 is a glass lens with positive optical power, its object side surface is convex, and its image side surface is concave;

[0069] The third lens 3 is a glass lens with a negative optical power, its object side is convex, and its image side is concave;

[0070] The fourth lens 4 is a glass lens with a positive optical power, its object side is convex, and its image side is concave;

[0071] The fifth lens 5 is a glass lens with a negative optical power, its object side is convex, and its image side is concave;

[0072] The sixth lens 6 is a glass lens with a negative optical power, its object side is convex, and its image side is concave;

[0073] The seventh lens 7 is a glass lens with a positive optical power, its object side is convex, and its image side is convex;

[0074] The eighth lens 8 is a glass lens with a negative optical power, its object side is concave, and its image side is concave;

[0075] The ninth lens 9 is a glass lens with a positive optical power, its object side is convex, and its image side is convex;

[0076] The tenth lens 10 is a glass lens with a positive optical power, its object side is convex, and its image side is convex.

[0077] In the present utility model, the lens further includes a protective glass, and the protective glass is integrated on the image acquisition element.

[0078] In the present utility model, in order to enable the optical system to exhibit better performance, during the design process, we need to reasonably select the lens materials, reasonably allocate the focal lengths of each lens, and reasonably optimize the optical system. Finally, to optimize the performance of the optical system, usually the existence of optical system aberrations will affect the imaging quality of the optical system. Correcting aberrations is the key to optimizing the optical system. There are many methods to correct aberrations. For example, using lenses with different refractive indices and significantly different Abbe numbers in combination can eliminate chromatic aberration and spherical aberration to a certain extent. Reasonably allocating and optimizing the focal lengths and shapes of each lens can also correct the aberrations of the system.

[0079] In the present utility model, f is the total focal length of the lens, f1 is the focal length of the first lens 1, f2 is the focal length of the second lens 2, f3 is the focal length of the third lens 3, f4 is the focal length of the fourth lens 4, f5 is the focal length of the fifth lens 5, f6 is the focal length of the sixth lens 6, f7 is the focal length of the seventh lens 7, f8 is the focal length of the eighth lens 8, f9 is the focal length of the ninth lens 9, and f10 is the focal length of the tenth lens 10. The ratios of the focal lengths of each lens to the total focal length of the lens satisfy the following conditions:

[0080] 0.65 ≤ f1 / f ≤ 0.73

[0081] 0.32 ≤ f2 / f ≤ 0.33,

[0082] -0.34 ≤ f3 / f ≤ -0.32,

[0083] 0.24 ≤ f4 / f ≤ 0.25,

[0084] -0.06 ≤ f5 / f ≤ -0.04,

[0085] -0.10 ≤ f6 / f ≤ -0.08,

[0086] 0.05 ≤ f7 / f ≤ 0.06,

[0087] -0.06 ≤ f8 / f ≤ -0.05,

[0088] 0.06 ≤ f9 / f ≤ 0.08,

[0089] 0.09 ≤ f10 / f ≤ 0.10,

[0090] In the present utility model, the focal lengths, refractive indices and radii of curvature of the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5, the sixth lens 6, the seventh lens 7, the eighth lens 8, the ninth lens 9 and the tenth lens 10 respectively satisfy the following conditions:

[0091] f1 +274.8～+303.6 ND1 1.76～1.86 R11 +170.8～+187.7 R12 +594.8～+680.4 f2 +137.4～+138.6 ND2 1.69～1.79 R21 +73.9～+75.9 R22 +218.3～+234.0 f3 -138.9～-135.1 ND3 1.85～1.95 R31 +388.1～+414.6 R32 +94.1～+94.3 f4 +102.2～+102.5 ND4 1.69～1.79 R41 +56.6～+57.4 R42 +196.7～+208.8 f5 -21.2～-20.7 ND5 1.55～1.65 R51 +160.8～+211.3 R52 +11.6～+12.2 f6 -39.9～-23.9 ND6 1.50～1.60 R61 +24.3～+27.1 R62 +10.5～+11.3 f7 +21.0～+21.4 ND7 1.68～1.78 R71 +37.5～+44.9 R72 -20.9～-19.8 f8 -24.0～-22.7 ND8 1.72～1.82 R81 -64.5～-47.8 R82 +27.3～+29.3 f9 +29.0～+30.2 ND9 1.59～1.69 R91 +45.3～+49.8 R92 -30.0～-29.6 f10 +38.6～+40.2 ND10 1.54～1.64 R101 +25.6～+26.6 R102 -389.3～-122.3

[0092] Among them, f1 is the focal length of the first lens, ND1 is the refractive index of the first lens, R11 is the curvature radius of the object side surface of the first lens, and R12 is the curvature radius of the image side surface of the first lens; f2 is the focal length of the second lens, ND2 is the refractive index of the second lens 2, R21 is the curvature radius of the object side surface of the second lens, and R22 is the curvature radius of the image side surface of the second lens; f is the focal length of the third lens, ND3 is the refractive index of the third lens, R31 is the curvature radius of the object side surface of the third lens, and R32 is the curvature radius of the image side surface of the third lens; f4 is the focal length of the fourth lens, ND4 is the refractive index of the fourth lens, R41 is the curvature radius of the object side surface of the fourth lens, and R42 is the curvature radius of the image side surface of the fourth lens; f5 is the focal length of the fifth lens, ND5 is the refractive index of the fifth lens, R51 is the curvature radius of the object side surface of the fifth lens, and R52 is the curvature radius of the image side surface of the fifth lens; f6 is the focal length of the sixth lens, ND6 is the refractive index of the sixth lens, R61 is the curvature radius of the object side surface of the sixth lens, and R62 is the curvature radius of the image side surface of the sixth lens; f7 is the focal length of the seventh lens, ND7 is the refractive index of the seventh lens, R71 is the curvature radius of the object side surface of the seventh lens, and R72 is the curvature radius of the image side surface of the seventh lens; f8 is the focal length of the eighth lens, ND8 is the refractive index of the eighth lens, R81 is the curvature radius of the object side surface of the eighth lens, and R82 is the curvature radius of the image side surface of the eighth lens; f9 is the focal length of the ninth lens, ND9 is the refractive index of the ninth lens, R91 is the curvature radius of the object side surface of the ninth lens, and R92 is the curvature radius of the image side surface of the ninth lens; f10 is the focal length of the tenth lens, ND10 is the refractive index of the tenth lens, R101 is the curvature radius of the object side surface of the tenth lens, and R102 is the curvature radius of the image side surface of the tenth lens;

[0093] Focal length: The "+" sign indicates that the lens has a positive optical power, and the "-" sign indicates that the lens has a negative optical power. The unit of the focal length is mm;

[0094] Radius of curvature: The "+" sign indicates that the surface bends towards the image side, and the "-" sign indicates that the surface bends towards the object side. The unit is mm.

[0095] In the present utility model, f is the total focal length of the lens; TTL is the total optical length of the lens; OBFL is the optical back focal length of the lens. The optical back focal length of the lens is defined as the distance from the closest point on the image side surface of the tenth lens 10 to the image plane; IC is the full image height of the chip matched with the lens system; they satisfy the following conditions:

[0096] TTL ≤ 255 mm,

[0097] f ≥ 420.033 mm,

[0098] OBFL ≥ 21.605 mm,

[0099] IC / TTL ≥ 0.05,

[0100] TTL / f ≤ 0.6,

[0101] OBFL / TTL ≥ 0.07.

[0102] In this utility model, the aperture of the lens is F#, satisfying F# ≥ 2.8; the working distance is 100 mm, the full object height is 150 mm; the working wavelength is visible light.

[0103] The following gives specific embodiments according to the above settings of this utility model to specifically illustrate the large-aperture double telecentric lens according to this utility model.

[0104] The data of the specific embodiments in the specific embodiments of this utility model are summarized as shown in Table 1 below:

[0105] Table 1

[0106]

[0107]

[0108] Example 1

[0109] Reference Figure 1 、 Figure 2 As shown, they are respectively the optical structure schematic diagram and the optical path structure schematic diagram of this Example 1.

[0110] In this embodiment, the total focal length f of the lens system is 420.033 mm, the aperture value F# is 2.8, the total optical length TTL of the lens is 255 mm, the optical back focal length OBFL of the lens is 21.605 mm, the magnification is 0.1×, and the distortion within the full field of view is controlled to be less than 0.06%.

[0111] In this embodiment, by reasonably selecting the lens materials and reasonably distributing the focal lengths and optical powers of each lens, the optical system is optimized to achieve uniform and insensitive thickness of each lens, which is easy to mass-produce on a large scale.

[0112] In this embodiment, the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5, and the sixth lens 6 adopt lenses with a combination of positive and negative optical powers in a meniscus shape with the convex surface facing the object side, and their function is to quickly converge light and correct distortion. The Abbe number of the material of the seventh lens 7 is greater than 46, and the Abbe number of the material of the eighth lens 8 is less than 28. Such a combination can reduce chromatic aberration. The object side of the ninth lens 9 and the tenth lens 10 is convex, and their image side is convex, and their main function is to improve the resolution.

[0113] In this embodiment, the radius of curvature (unit: mm), central thickness d (unit: mm), refractive index (ND), and Abbe number (VD) of the first lens 1, second lens 2, third lens 3, fourth lens 4, fifth lens 5, sixth lens 6, seventh lens 7, eighth lens 8, ninth lens 9, and tenth lens 10 are shown in Table 2.

[0114] Table 2

[0115]

[0116]

[0117] In Table 2, the radius of curvature R represents the degree of curvature of the lens surface. A positive value indicates that the surface is curved towards the image side, and a negative value indicates that the surface is curved towards the object side. "INFINITY" represents that the surface is a plane; the central thickness D represents the central axial distance from the current surface to the next surface. The refractive index ND represents the ability of the current lens material to deflect light, and the Abbe number VD represents the dispersion characteristics of the current lens material to light; 11 represents the object side of the first lens 1, 12 represents the image side of the first lens 1, and so on.

[0118] Reference Figure 3 As shown, it is the field curvature curve graph and distortion curve graph of the lens in this embodiment. Among them, in the field curvature curve graph, the vertical coordinate ASTIGMATIC FIELD CURVES represents different fields of view, and the horizontal coordinate FOCUS (MILLIMETERS) represents the amount of field curvature (mm); it can be seen from Figure 3 that the field curvature offset of the meridian direction and the sagittal direction on the image plane are both controlled within ±0.06 mm, indicating that the field curvature of the lens is well corrected; in the distortion curve graph, the horizontal axis represents the F - tan(Theta) distortion (unit: %), and the vertical axis represents the semi-image height value (unit: mm). It can be seen from the figure that the distortion within the full field of view of the lens is within -0.06%, indicating that the distortion is well corrected.

[0119] Reference Figure 4 As shown, the horizontal axis represents the resolution (unit: lp / mm), and the vertical axis represents the MTF value. In the visible light range of 0.486 - 0.656 μm, the average MTF value of the lens in this embodiment at a resolution of 125 lp / mm is greater than 0.4, and the entire MTF curve is compact, indicating that the lens has a high resolution.

[0120] From Figure 3 , 4 it can be seen that the field curvature, distortion, and MTF of the lens in this embodiment can all be well corrected.

[0121] Embodiment 2

[0122] Reference Figure 5 and Figure 6 shown, which are respectively the optical structure schematic diagram and the optical path structure schematic diagram of Embodiment 2 of the present invention.

[0123] In this embodiment, the total focal length f of the lens system is 420.038 mm, the aperture value F# is 2.8, the total optical length TTL of the lens is 246.26 mm, the optical back focal length OBFL of the lens is 20.017 mm, the magnification is 0.1×, and the distortion within the entire field of view is controlled to be less than 0.12%.

[0124] In this embodiment, by reasonably selecting the lens materials and rationally distributing the focal lengths and optical powers of each lens, the optical system is optimized to achieve uniform and insensitive thickness of each lens, making it easy for large-scale batch manufacturing.

[0125] In this embodiment, the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5, and the sixth lens 6 adopt lenses with a combination of positive and negative optical powers in a meniscus shape with the convex surface facing the object side, whose function is to quickly converge light and correct distortion. The Abbe number of the material of the seventh lens 7 is greater than 46, and the Abbe number of the material of the eighth lens 8 is less than 28. Such a combination can reduce chromatic aberration. The object side of the ninth lens 9 and the tenth lens 10 is convex, and their image sides are convex, and their main function is to improve the resolution.

[0126] In this embodiment, the radius of curvature (unit: mm), the central thickness d (unit: mm), the refractive index (ND), and the Abbe constant (VD) of the first lens 1, the second lens 2, the third lens 3, the fourth lens 4, the fifth lens 5, the sixth lens 6, the seventh lens 7, the eighth lens 8, the ninth lens 9, and the tenth lens 10 are shown in Table 3.

[0127] Table 3

[0128]

[0129]

[0130] In Table 3, the radius of curvature R represents the degree of curvature of the lens surface. A positive value represents that the surface bends towards the image side, and a negative value represents that the surface bends towards the object side, where "INFINITY" represents that the surface is a plane; the central thickness D represents the central axial distance from the current surface to the next surface, the refractive index ND represents the ability of the current lens material to deflect light, and the Abbe number VD represents the dispersion characteristics of the current lens material to light; 11 represents the object side of the first lens 1, 12 represents the image side of the first lens 1, and so on.

[0131] Reference Figure 7As shown, the field curvature curve graph and distortion curve graph of the lens in this embodiment are presented. Among them, in the field curvature curve graph, the vertical coordinate ASTIGMATIC FIELD CURVES represents different fields of view, and the horizontal coordinate FOCUS(MILLIMETERS) represents the field curvature amount (mm); from Figure 7 it can be seen that the field curvature offset amounts in the meridional direction and sagittal direction on the image plane are both controlled within ±0.06 mm, indicating that the field curvature correction of this lens is good; in the distortion curve graph, the horizontal axis represents the F-tan(Theta) distortion (unit: %), and the vertical axis represents the semi-image height value (unit: mm). From the graph, it can be seen that within the full field of view of the lens, the distortion is within ±0.12%, indicating that the distortion is well corrected.

[0132] Reference Figure 8 As shown, the horizontal axis represents the resolution (unit: lp / mm), and the vertical axis represents the MTF value. Within the visible light range of 0.486 - 0.656 μm, the average MTF value of the lens in this embodiment at a resolution of 125 lp / mm is greater than 0.4, and the entire MTF curve is compact, indicating that the lens has a high resolution.

[0133] From Figure 7 and 8 it can be seen that the field curvature, distortion, and MTF of the lens in this embodiment can all be well corrected.

[0134] In this embodiment 2, the total focal length f of the lens system is 420.038 mm, the aperture value F# is 2.8, the optical total length TTL of the lens is 246.26 mm, the optical back focal length OBFL of the lens is 20.017 mm, the magnification is 0.1×, and the distortion within the full field of view is controlled to be less than 0.12%.

[0135] From the F-Tan(θ) distortion curve graph, field curvature curve graph, and MTF curve graph of each of the above embodiments, it can be seen that the optical lens provided by the present utility model has high resolving power, that is, it can achieve advantages such as high imaging quality and high pixels. With a large aperture, it can achieve a larger light passing amount, and at the same time has good manufacturability and yield.

[0136] According to the disclosure of the above specification, those skilled in the art to which the present utility model pertains can also make appropriate changes and modifications to the above embodiments. Therefore, the present utility model is not limited to the specific embodiments disclosed and described above, and some modifications and changes to the present utility model should also fall within the protection scope of the claims of the present utility model. In addition, although some specific terms are used in this specification, these terms are only for convenience of description and do not constitute any limitation to the present utility model.

Claims

1. A large aperture bi-telecentric lens, characterized in that: A first optical path portion, an aperture stop, and a second optical path portion are sequentially arranged along the optical axis of the lens from the object side to the image side; The first optical path parts are arranged in sequence from the object side to the image side along the optical axis of the lens: A first lens, wherein the first lens is a glass lens with positive power, the object side surface of the first lens is a convex surface, and the image side surface of the first lens is a concave surface; a second lens, wherein the second lens is a glass lens with positive refractive power, the object side surface of the second lens is a convex surface, and the image side surface of the second lens is a concave surface; A third lens, wherein the third lens is a glass lens with negative optical power, the object side surface of the third lens is a convex surface, and the image side surface is a concave surface; a fourth lens, wherein the fourth lens is a glass lens with positive refractive power, the object side surface of the fourth lens is a convex surface, and the image side surface is a concave surface; A fifth lens, wherein the fifth lens is a glass lens with negative optical power, the object side surface of the fifth lens is a convex surface, and the image side surface is a concave surface; a sixth lens, wherein the sixth lens is a glass lens with negative optical power, the object side surface of the sixth lens is a convex surface, and the image side surface is a concave surface; The second optical path part is arranged in sequence from the object side to the image side along the optical axis of the lens: A seventh lens, wherein the seventh lens is a glass lens with positive power, and the object-side surface of the seventh lens is a convex surface, and the image-side surface is a convex surface; an eighth lens, wherein the eighth lens is a glass lens with negative optical power, and the object-side surface of the eighth lens is a concave surface, and the image-side surface of the eighth lens is a concave surface; A ninth lens, wherein the ninth lens is a glass lens with positive power, and the object side surface of the ninth lens is a convex surface, and the image side surface is a convex surface; The tenth lens is a glass lens with positive optical power, the object side surface of the tenth lens is a convex surface, and the image side surface is a convex surface.

2. The large aperture bi-telecentric lens according to claim 1, characterized in that: The lens satisfies the following relationship: IC / TTL ≥ 0.05, TTL / f≤0.6, OBFL / TTL ≥ 0.07; In the relationship, f is the total focal length of the lens, TTL is the total optical length of the lens, OBFL is the optical back focus of the lens, and IC is the total image height of the chip matched with the lens system.

3. The large aperture bi-telecentric lens according to claim 1, characterized in that: The lens satisfies the following relationship: F#≥2.8， TTL≤255mm, f≥420.033mm, OBFL ≥ 21.605 mm; Among them, F# is the aperture of the lens, f is the total focal length of the lens, TTL is the total optical length of the lens, and OBFL is the optical back focus of the lens.

4. The large aperture bi-telecentric lens according to claim 1, characterized in that: The focal length ranges corresponding to the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens and the tenth lens are respectively +274.8 to +303.6, +137.4 to +138.6, -138.9 to -135.1, +102.2 to +102.5, -21.2 to -20.7, -39.9 to -23.9, +21.0 to +21.4, -24.0 to -22.7, +29.0 to +30.2, and +38.6 to +40.2, and the unit of the focal length is mm.

5. The large aperture bi-telecentric lens according to claim 1, characterized in that: The refractive index value ranges corresponding to the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens, and the tenth lens are respectively: 1.76～1.86、1.69～1.79、1.85～1.95、1.69～1.79、1.55～1.65、1.50～1.60、1.68～1.78、1.72～1.82、1.59～1.69、1.54～1.64。 6. The large aperture bi-telecentric lens according to claim 1, characterized in that: The object side surface radii of curvature corresponding to the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens and the tenth lens are respectively in the range of +170.8 to +187.7, +73.9 to +75.9, +388.1 to +414.6, +56.6 to +57.4, +160.8 to +211.3, +24.3 to +27.1, +37.5 to +44.9, -64.5 to -47.8, +45.3 to +49.8 and +25.6 to +26.6, and the unit of the curvature radius is mm.

7. The large aperture bi-telecentric lens according to claim 1, characterized in that: The image-side surface curvature radii corresponding to the first lens, the second lens, the third lens, the fourth lens, the fifth lens, the sixth lens, the seventh lens, the eighth lens, the ninth lens and the tenth lens are respectively in the range of +594.8 to +680.4, +218.3 to +234.0, +94.1 to +94.3, +196.7 to +208.8, +11.6 to +12.2, +10.5 to +11.3, -20.9 to -19.8, +27.3 to +29.3, -30.0 to -29.6, and -389.3 to -122.3, and the unit of the curvature radius is mm.

8. The large aperture bi-telecentric lens according to claim 1, characterized in that: The lens satisfies the following relationship: 0.65≤f1 / f≤0.73, 0.32≤f2 / f≤0.33, -0.34≤f3 / f≤-0.32, 0.24≤f4 / f≤0.25, -0.06≤f5 / f≤-0.04, -0.10≤f6 / f≤-0.08, 0.05≤f7 / f≤0.06, -0.06≤f8 / f≤-0.05, 0.06≤f9 / f≤0.08, 0.09≤f10 / f≤0.10, In the relationship, f is the total focal length of the lens, f1 is the focal length of the first lens, f2 is the focal length of the second lens, f3 is the focal length of the third lens, f4 is the focal length of the fourth lens, f5 is the focal length of the fifth lens, f6 is the focal length of the sixth lens, f7 is the focal length of the seventh lens, f8 is the focal length of the eighth lens, f9 is the focal length of the ninth lens, and f10 is the focal length of the tenth lens.

9. The large aperture bi-telecentric lens according to claim 1, characterized in that: The aperture of the lens is F#, which satisfies F#≥2.8 to ensure a large amount of light entering.

10. A large aperture bi-telecentric lens according to any one of claims 1 to 9, characterized in that: Along the lens optical axis from the object side to the image side, it is also set: The aperture stop is located on the object side of the seventh lens; An image collection element is arranged on the image side surface of the tenth lens.

Images