TW201917434A - Photographing lens - Google Patents

Abstract

A photographing lens includes, from an object side to an image side along an optical axis, a first lens that is a meniscus lens having a negative refractive power, having an object-side surface being convex in a paraxial region thereof and an image-side surface being concave in a paraxial region thereof; a second lens having a negative refractive power; a third lens that is a biconvex lens having a positive refractive power; a fourth lens that is a biconvex lens having a positive refractive power; and a fifth lens that is a lens having a negative refractive power, having an object-side surface being concave in a paraxial region thereof. The photographing lens has an excellent ability of image resolution.

Description

Camera lens

The invention relates to an optical element, in particular to an imaging lens.

In recent years, in-vehicle lenses (such as driving recorder lenses, reversing development lenses, and automatic driving lenses) applied to vehicles have gradually developed. Generally, the environment for using this type of lens has a large difference between high and low temperature. In order to resist temperature changes, this type of lens uses glass as the material of the lens. Because the thermal expansion coefficient of plastic material is much larger than that of glass, it is generally difficult to compensate for temperature effects. However, the glass material is generally more expensive than the plastic material, so there is a problem that the cost is not easy to drop. Others like monitor lenses and drone aerial lenses have the same problem.

An object of the present invention is to provide an imaging lens having characteristics of a small number of components and good resolution.

The imaging lens provided by the present invention includes, in order from the object side to the image side, an optical axis: a first lens, a second lens, a third lens, a fourth lens, and a fifth lens. The first lens is a meniscus lens with negative refractive power, and its object-side surface is convex at the near optical axis, and its image-side surface is concave at the near optical axis. The second lens is a lens with negative refractive power. The third lens is a biconvex lens with positive refractive power. The fourth lens is a biconvex lens with positive refractive power. The fifth lens is a lens with negative refractive power, and its object-side surface is concave at the near optical axis.

The imaging lens of the present invention may further include a sixth lens disposed between the fifth lens and an imaging plane. The sixth lens is a lens with negative refractive power, and the object-side surface is convex at the near optical axis. The image side surface is concave at the near optical axis.

The object-side surface of the second lens is concave.

The camera lens satisfies the following conditional expressions: , 25°< CRA <40°; where n1 is the refractive index of the first lens, n2 is the refractive index of the second lens, n3 is the refractive index of the third lens, and n4 is the refractive index of the fourth lens, n5 is the refractive index of the fifth lens, f1 is the focal length of the first lens (unit: mm), f2 is the focal length of the second lens (unit: mm), and f3 is the focal length of the third lens (unit: mm) ), f4 is the focal length (in mm) of the fourth lens, f5 is the focal length (in mm) of the fifth lens, and CRA is the maximum angle at which the chief ray enters the imaging plane.

The camera lens satisfies the following conditional expression: 0.2 1.4.5> >2, 2.5> >0.5; where f is the effective focal length of the camera lens (in mm), L 1 is the maximum effective diameter of the first lens (unit: mm), IH is the maximum imaging height of the camera lens in the imaging plane (unit: mm), and T 2 is the center thickness value of the second lens (unit: mm) ).

The camera lens satisfies the following conditional expression: 3> >0.5, 40 ( V 4 d - V 5 d ) 23; where V 1 d is the Abbe number of the first lens, V 3 d is the Abbe number of the third lens, V 4 d is the Abbe number of the fourth lens, and V 5 d is The Abbe coefficient of the fifth lens.

The distance between the edge of the image-side surface of the first lens and the edge of the object-side surface of the second lens in the optical axis direction is between 0 and 1 mm.

The camera lens satisfies the following conditional expression: 1 2.8, 4< <10; where f 3 is the focal length of the third lens (in mm), f is the effective focal length of the camera lens (in millimeters), and TTL is the total length of the camera lens (in mm).

In another embodiment of the imaging lens of the present invention, it includes, in order from the object side to the image side, on the optical axis: a first lens, a second lens, a third lens, a fourth lens and a fifth lens . The first lens is a meniscus lens with negative refractive power. The second lens is a lens with negative refractive power, and its image side surface is concave. The third lens is a lens with positive refractive power, and its image side surface is convex. The fourth lens is a lens with positive refractive power. The fifth lens is a lens with negative refractive power, and its object side surface is concave, wherein the imaging lens satisfies the following conditional expression: 1> >0.2, where T 2 is the center thickness value of the second lens (in mm), and TTL is the total length of the imaging lens (in mm).

In another embodiment of the imaging lens of the present invention, it includes, in order from the object side to the image side, the optical axis: a first lens, a second lens, a third lens, an aperture, a fourth lens, and a The fifth lens. The first lens is a meniscus lens with negative refractive power. The second lens is a lens with negative refractive power, and its image side surface is concave. The third lens is a lens with positive refractive power, and its image side surface is convex. The fourth lens is a lens with positive refractive power. The fifth lens is a biconcave lens with negative refractive power.

The imaging lens of the present invention has the advantages of fewer components and good resolution. Moreover, in a specific embodiment, the present invention can adopt a special combination of plastic and glass to achieve the effect of compensating for the temperature effect, and can achieve the purpose of cost reduction while maintaining a certain degree of optical performance.

G‧‧‧protective glass

IMA‧‧‧Imaging plane

L1‧‧‧ First lens

L2‧‧‧Second lens

L3‧‧‧third lens

L4‧‧‧ fourth lens

L5‧‧‧fifth lens

L6‧‧‧Sixth lens

OA‧‧‧ Optical axis

OF‧‧‧filter

ST‧‧‧ Aperture

FIG. 1A shows a schematic diagram of a camera lens according to a first embodiment of the invention.

FIGS. 1B to 1D are the field curvature, distortion, and longitudinal aberration diagrams of the first embodiment, respectively.

FIG. 2A shows a schematic diagram of a camera lens according to a second embodiment of the invention.

Figures 2B to 2D are the field curvature, distortion, and longitudinal aberration diagrams of the second embodiment, respectively, in that order.

FIG. 3A shows a schematic diagram of a camera lens according to a third embodiment of the invention.

Figures 3B to 3D are the field curvature, distortion, and longitudinal aberration diagrams of the third embodiment, respectively.

FIG. 4A shows a schematic diagram of a camera lens according to a fourth embodiment of the invention.

FIGS. 4B to 4D are the field curvature, distortion, and longitudinal aberration diagrams of the fourth embodiment, respectively.

FIG. 5A shows a schematic diagram of a camera lens according to a fifth embodiment of the invention.

FIGS. 5B to 5D are the field curvature, distortion, and longitudinal aberration diagrams of the fifth embodiment, respectively.

FIG. 6A shows a schematic diagram of a camera lens according to a sixth embodiment of the invention.

FIGS. 6B to 6D are the field curvature, distortion, and longitudinal aberration diagrams of the sixth embodiment, respectively, in that order.

In order to make the above and other objects, features, and advantages of the present invention more comprehensible, the preferred embodiments of the present invention will be specifically described below in conjunction with the accompanying drawings, which are described in detail below.

Please refer to FIG. 1A, FIG. 2A and FIG. 3A, the imaging lens of the present invention sequentially includes a first lens L1, a second lens L2, and a third lens L3 from the object side to the image side along the optical axis OA , A fourth lens L4 and a fifth lens L5, and further includes an aperture ST located between the object-side surface of the fourth lens L4 and the image-side surface of the third lens L3, located between the fifth lens L5 and the imaging plane IMA Between the filter OF and the protective glass G.

The first lens L1 is a meniscus lens with negative refractive power, and its object-side surface is convex at the near optical axis, and its image-side surface is concave at the near optical axis. The second lens L2 is a lens with negative refractive power. The third lens L3 is a biconvex lens with positive refractive power. The fourth lens L4 is a biconvex lens with positive refractive power. The fifth lens L5 is a lens with negative refractive power, and its object-side surface is concave at the near optical axis.

Please refer to FIG. 4A, FIG. 5A and FIG. 6A, the imaging lens of the present invention can add a lens under the framework of the above five lenses, that is, the imaging lens further includes a sixth lens L6, which is disposed on the fifth lens Between L5 and the imaging plane IMA, the optical architecture of six lenses is formed. Specifically, the sixth lens L6 is a lens with negative refractive power, and its object-side surface is convex at the near optical axis, and its image-side surface is concave at the near optical axis.

The camera lens of the present invention has the advantages of small number of components and good resolution, and can be used in the fields of vehicle-mounted lenses, surveillance lenses, UAV aerial lenses, etc., but it is not limited to this. The camera lens of the present invention can also be applied in various ways to various lens-equipped imaging devices, such as personal information terminals (such as mobile phones, smart phones, and tablet computers), wearable devices, IP CAM, game consoles, and 3D image capture Device etc.

The second lens L2 may be a double concave lens. The second lens L2 may be a lens in which the object-side surface is convex at the low optical axis and the image-side surface is concave at the low optical axis.

The fifth lens L5 may be a double concave lens. The fifth lens L5 may be a lens in which the object-side surface is concave at the low optical axis and the image-side surface is convex at the low optical axis.

Preferably, the first lens L1 and the third lens L3 are glass spherical lenses, and the second lens L2, the fourth lens L4 and the fifth lens L5 are plastic lenses, which can resist the temperature change of the environment while reducing the cost Effect, maintaining excellent resolution quality. Of course, the present invention can also be implemented with a combination of other types of glass lenses and plastic lenses, as well as aspheric lenses.

Preferably, the image-side surface of the fourth lens (denoted as L4R2) is spherical. Of course, the present invention can also be implemented with an aspheric lens.

In the imaging lens, the object-side surface and the image-side surface of each lens can be an aspheric surface (ASP). The aspheric surface can obtain more control variables to reduce aberrations, thereby reducing the number of lenses used and shortening the total lens length. Preferably, the object side surface and the image side surface (L2R1 and L2R2) of the second lens L2, the object side surface (L4R1) of the fourth lens L4 and the object side surface and the image side surface (L5R1 and L5R2) of the fifth lens L5 ) Is an aspheric surface. Preferably, the object-side surfaces and the image-side surfaces of the second lens L2 to the sixth lens L6 (that is, L2R1, L2R2, L3R1, L3R2, L4R1, L4R2, L5R1, L5R2, L6R1, and L6R2) are all aspherical surfaces.

Furthermore, in order for the imaging lens of the present invention to maintain good optical performance, the imaging lens of the present invention can further satisfy the following conditions.

The field of curvature of the imaging lens of the present invention satisfies the following conditional expression (1): Where n1 is the refractive index of the first lens L1, n2 is the refractive index of the second lens L2, n3 is the refractive index of the third lens, n4 is the refractive index of the fourth lens, and n5 is the refractive index of the fifth lens L5 , F1 is the focal length of the first lens L1, f2 is the focal length of the second lens L2, f3 is the focal length of the third lens, f4 is the focal length of the fourth lens, and f5 is the focal length of the fifth lens L5. among them, Become a Petzval sum. In other words, the imaging lens of the present invention has a small curvature of the image field, and the image field projection will not be excessively distorted when it is projected on the imaging plane.

The imaging lens of the present invention can satisfy the following conditional expression (2): Where f is the effective focal length (unit: mm) of the imaging lens, and L 1 R 1 Rm is the maximum effective diameter (unit: mm) of the first lens L1 (can also be written as ΦL1). In this way, the total length of the lens can be effectively controlled to achieve the effect of miniaturization.

The imaging lens of the present invention can further satisfy the following condition (3) to further maintain optical performance.

Where V 4 d is the Abbe number of the fourth lens L4 and V 5 d is the Abbe number of the fifth lens L5.

Further, in the imaging lens of the present invention, the distance between the edge of the image-side surface of the first lens L1 (that is, L1R2) and the edge of the object-side surface of the second lens L2 (that is, L2R1) in the direction of the optical axis OA ranges from 0 to Between 1mm.

The imaging lens of the present invention can satisfy the following conditional expression (4): Where f 3 is the focal length of the third lens L3, and f is the effective focal length of the imaging lens. In this way, the diopter configuration of the camera lens can be adjusted to meet more diverse applications.

The imaging lens of the present invention can further satisfy the following condition (5) to control the configuration of lens thickness.

Where T 2 is the center thickness value of the second lens L2 (unit is mm), TTL is the total length of the imaging lens (unit is mm), that is, the object side surface of the first lens L1 to the imaging plane IMA on the optical axis distance.

The imaging lens of the present invention can further satisfy the following condition (6): Where TTL is the total length of the camera lens, and f is the effective focal length of the camera lens. In this way, while satisfying shooting distant images, the total length of the camera lens is effectively controlled.

The imaging lens of the present invention can further satisfy the following condition (7): 25°< CRA <40° (7) where CRA is the maximum angle at which the chief rays enter the imaging plane IMA.

The imaging lens of the present invention can further satisfy the following condition (8): among them L 1 is the maximum effective diameter of the first lens L1 (in mm), IH maximum imaging lens for imaging the imaging plane IMA height or maximum radius imaging (in mm).

The imaging lens of the present invention can further satisfy the following condition (9): Where T 2 is the center thickness value of the second lens L2 (unit is mm), and IH is the maximum imaging height or maximum imaging circle radius of the imaging lens in the imaging plane IMA (unit is mm).

The imaging lens of the present invention can further satisfy the following condition (10) to further maintain optical performance.

Where V 1 d is the Abbe coefficient of the first lens L1, and V 3 d is the Abbe coefficient of the third lens L3.

The imaging lens of the present invention can further satisfy the following condition (11): Where TTL is the total length of the camera lens, and f is the effective focal length of the camera lens. In this way, while satisfying shooting distant images, the total length of the camera lens is effectively controlled.

The camera lens of the present invention will be further described in detail below with specific examples.

The shape of the aspheric lens can be expressed as follows: Where D is the amount of Sag at the relative height of the aspheric lens at the center axis of the lens, C is the reciprocal of the radius of the paraxial curvature radius, H is the relative height of the aspheric lens at the center axis, and K is the aspheric lens Conic constant (Conic Constant), and E ₄ ~ E ₁₂ fourth-order or higher order aspheric correction coefficient.

First embodiment:

Please refer to FIGS. 1A to 1D, wherein FIG. 1A shows a schematic diagram of a camera lens according to the first embodiment of the present invention, and FIGS. 1B to 1D are the field curvature, distortion, and longitudinal image of the first embodiment, respectively, in order. Difference chart. The first embodiment is a five-piece lens (that is, L1-L5) structure, and the second lens L2 and the fifth lens L5 are double-concave lenses. Table 1 is the related parameter table of each lens of the optical lens in FIG. 1A, and Table 2 is the related parameter table of each aspheric surface of each lens in Table 1. Among them, the Petzval sum is -0.014, which is between -1 and 1. The effective focal length of the camera lens is 1.8942 mm, and the maximum effective diameter of the first lens L1 (that is, L 1 R 1 Rm ) is 7.2 mm, so = 0.263, between 0.2 and 1. The Abbe coefficient of the fourth lens L4 is 56, and the Abbe coefficient of the fifth lens L5 is 23. Therefore, ( V 4 d - V 5 d )=33, which is between 23 and 40. The distance between the edge of the L1R2 surface and the edge of the L2R1 surface in the optical axis direction is 0.298 mm, and is between 0 and 1 mm. The focal length of the third lens L3 is 4.6429mm, so , Between 1 and 2.8. The central thickness value T2 of the second lens L2 is 3.289 mm, and the total lens length is 15.915 mm, so T2/TTL = 0.207, between 0.2 and 1, and TTL/f = 8.402, between 4.4 and 10. The CRA is 26.05 degrees, between 25 and 40 degrees. IH is 1.7mm, so , Between 2 and 4.5. , Between 0.5 and 2.5. The Abbe coefficient of the first lens L1 is 53, and the Abbe coefficient of the third lens L3 is 63, so , Between 0.5 and 3.

If the value of condition (4) f3/f is less than 1, the manufacturability of the lens is poor, and the lens light will be too convergent, and the surroundings cannot be well resolved; if the value of condition (4) f3/f is greater than 2.8, the lens The light will be too divergent and the full length of the lens will be too long to satisfy the lens miniaturization. Therefore, the value of f3/f must be at least greater than 1, so the best effect range is 1 2.8, within this range, a better balance between optical characteristics and lens manufacturability can be achieved, where if the value of f3/f tends to be larger, better lens manufacturability can be obtained, if the value of f3/f tends to be smaller , You can get a higher peripheral resolution performance.

If the value of condition (11) TTL/f is greater than 10, it is difficult to achieve the purpose of lens miniaturization. Therefore, the value of TTL/f must be at least less than 10, so the best effect range is 6< <10, within this range, the conditions for optimal lens miniaturization are met.

Second embodiment:

Please refer to FIGS. 2A to 2D, where FIG. 2A shows a schematic diagram of a camera lens according to a second embodiment of the present invention, and FIGS. 2B to 2D are the field curvature, distortion, and longitudinal image of the second embodiment, respectively, in that order. Difference chart. The second embodiment is a five-piece lens (that is, L1-L5) structure, and the second lens L2 and the fifth lens L5 are double-concave lenses. Table 3 is a table of related parameters of each lens of the optical lens in FIG. 2A, and Table 4 is a table of related parameters of the aspherical surfaces of each lens in Table 3. Among them, the Petzval sum is -0.03, which is between -1 and 1. The effective focal length of the camera lens is 1.8922mm, and the maximum effective diameter of the first lens L1 (that is, L 1 R 1 Rm ) is 7.2mm, so = 0.263, between 0.2 and 1. The Abbe coefficient of the fourth lens L4 is 55, and the Abbe coefficient of the fifth lens L5 is 25, so ( V 4 d - V 5 d )=30, between 23 and 40. The distance between the edge of the L1R2 surface and the edge of the L2R1 surface in the optical axis direction is 0.337 mm, and is between 0 and 1 mm. The focal length of the third lens L3 is 4.6225mm, so , Between 1 and 2.8. The central thickness value T2 of the second lens L2 is 3.284 mm, and the total lens length is 16.124 mm, so T2/TTL = 0.204, between 0.2 and 1, and TTL/f = 8.521, between 4.4 and 10. The CRA is 26.93 degrees, between 25 and 40 degrees. IH is 1.7mm, so , Between 2 and 4.5. , Between 0.5 and 2.5. The Abbe coefficient of the first lens L1 is 54 and the Abbe coefficient of the third lens L3 is 66, so , Between 0.5 and 3.

If the value of condition (3) V 4 d - V 5 d is less than 23, the achromatic function is poor, that is, the achromatic double lens must be relatively curved, and if the R value is too small, high-order aberrations are likely to occur. Therefore, the value of V 4 d - V 5 d must be at least greater than or equal to 23, so the best effect range is 40 ( V 4 d - V 5 d ) 23. Within this range, it has the best achromatic conditions.

If the value of condition (11) TTL/f is greater than 10, it is difficult to achieve the purpose of lens miniaturization. Therefore, the value of TTL/f must be at least less than 10, so the best effect range is 6< <10, within this range, the conditions for optimal lens miniaturization are met.

Third embodiment:

Please refer to FIGS. 3A to 3D, where FIG. 3A shows a schematic diagram of a camera lens according to a third embodiment of the present invention, and FIGS. 3B to 3D are the field curvature, distortion, and longitudinal image of the third embodiment, respectively, in that order. Difference chart. The third embodiment is a five-lens (L1-L5) architecture, and the second lens L2 and the fifth lens L5 are double-concave lenses. Table 5 is the related parameter table of each lens of the optical lens in FIG. 3A, and Table 6 is the related parameter table of the aspherical surface of each lens in Table 5. Among them, the Petzval sum is -0.015, which is between -1 and 1. The effective focal length of the camera lens is 1.8143 mm, and the maximum effective diameter of the first lens L1 (that is, L 1 R 1 Rm ) is 7.2 mm, so =0.252, between 0.2 and 1. The Abbe coefficient of the fourth lens L4 is 55, and the Abbe coefficient of the fifth lens L5 is 23. Therefore, ( V 4 d - V 5 d )=32, which is between 23 and 40. The distance between the edge of the L1R2 surface and the edge of the L2R1 surface in the optical axis direction is 0.29 mm, and is between 0 and 1 mm. The focal length of the third lens L3 is 4.5139mm, so , Between 1 and 2.8. The central thickness value T2 of the second lens L2 is 3.283 mm, and the total lens length is 16.063 mm, so T2/TTL = 0.204, which is between 0.2 and 1, and TTL/f = 8.854, which is between 4.4 and 10. The CRA is 26.67 degrees, between 25 and 40 degrees. IH is 1.7mm, so , Between 2 and 4.5. , Between 0.5 and 2.5. The Abbe coefficient of the first lens L1 is 52, and the Abbe coefficient of the third lens L3 is 60, so , Between 0.5 and 3.

If the value of condition (10) V 1 d / V 3 d is less than 0.5, the achromatic function is not good. Therefore, the value of V 1 d / V 3 d must be at least greater than 0.5, so the best effect range is 3> >0.5, the best achromatic condition is within the range.

If the value of condition (11) TTL/f is greater than 10, it is difficult to achieve the purpose of lens miniaturization. Therefore, the value of TTL/f must be at least less than 10, so the best effect range is 6< <10, within this range, the conditions for optimal lens miniaturization are met.

Fourth embodiment:

Please refer to FIGS. 4A to 4D, where FIG. 4A shows a schematic diagram of a camera lens according to a fourth embodiment of the present invention, and FIGS. 4B to 4D are the field curvature, distortion, and longitudinal image of the fourth embodiment, respectively. Difference chart. The fourth embodiment is a six-lens (L1~L6) architecture. The second lens L2 is a lens with a convex surface on the near optical axis and a concave image surface on the near optical axis. The fifth lens L5 It is a lens in which the object-side surface is concave at the low optical axis and the image-side surface is convex at the low optical axis. Table 7 is a table of related parameters of each lens of the optical lens in FIG. 4A, and Table 8 is a table of related parameters of the aspherical surfaces of each lens in Table 7. Among them, the Petzval sum is 0.07, which is between -1 and 1. The imaging lens aperture value (F-number) is 2.4, the effective focal length of 4.006mm, the maximum effective diameter of the first lens L1 (i.e., L 1 R 1 Rm or ΦL1) is 12.80mm, so = 0.313, between 0.2 and 1. The Abbe coefficient of the fourth lens L4 is 56.1, and the Abbe coefficient of the fifth lens L5 is 20.4, so ( V 4 d - V 5 d )=35.7, which is between 23 and 40. The distance between the edge of the L1R2 surface and the edge of the L2R1 surface in the optical axis direction is 0.61 mm, and is between 0 and 1 mm. The focal length of the third lens L3 is 5.229mm, so , Between 1 and 2.8. The center thickness value T2 of the second lens L2 is 4.301 mm, and the total lens length is 17.787 mm, so T2/TTL = 0.242, which is between 0.2 and 1, and TTL/f = 4.440, which is between 4.4 and 10. The CRA is 36.9 degrees, between 25 and 40 degrees. IH is 3.758mm, so , Between 2 and 4.5, and , Between 0.5 and 2.5. The Abbe coefficient of the first lens L1 is 68.6, and the Abbe coefficient of the third lens L3 is 31.6, so = 2.17, between 0.5 and 3.

If the value of condition (6) TTL/f is greater than 10, it is difficult to achieve the purpose of lens miniaturization. Therefore, the value of TTL/f must be at least less than 10, so the best effect range is 4< <10, within this range, the conditions for optimal lens miniaturization are met.

Fifth embodiment:

Please refer to FIGS. 5A to 5D, where FIG. 5A shows a schematic diagram of a camera lens according to a fifth embodiment of the present invention, and FIGS. 5B to 5D are the field curvature, distortion, and longitudinal image of the fifth embodiment, respectively, in that order. Difference chart. The fifth embodiment is a six-lens (L1~L6) structure. The second lens L2 is a lens with a convex surface on the near optical axis and a concave image surface on the near optical axis. The fifth lens L5 It is a biconcave lens. Table 9 is a table of related parameters of each lens of the optical lens in FIG. 5A, and Table 10 is a table of related parameters of the aspherical surfaces of each lens in Table 9. Among them, the Petzval sum is 0.073, which is between -1 and 1. The aperture value (F-number) of the camera lens is 2.4, the effective focal length is 3.939mm, and the maximum effective diameter of the first lens L1 (that is, L 1 R 1 Rm or ΦL1) is 11.86mm, so , Between 0.2 and 1. The Abbe coefficient of the fourth lens L4 is 56.1, and the Abbe coefficient of the fifth lens L5 is 20.4, so ( V 4 d - V 5 d )=35.7, which is between 23 and 40. The distance between the edge of the L1R2 surface and the edge of the L2R1 surface in the optical axis direction is 0.64 mm, and is between 0 and 1 mm. The focal length of the third lens L3 is 4.504mm, so , Between 1 and 2.8. The central thickness value T2 of the second lens L2 is 3.909 mm, and the total lens length is 17.91 mm, so T2/TTL = 0.217, which is between 0.2 and 1, and TTL/f = 4.567, which is between 4.4 and 10. The CRA is 37.8 degrees, between 25 and 40 degrees. IH is 3.758mm, so , Between 2 and 4.5, and , Between 0.5 and 2.5. The Abbe coefficient of the first lens L1 is 67, and the Abbe coefficient of the third lens L3 is 31.6, so , Between 0.5 and 3.

If the condition (7) CRA angle is less than 25 degrees, it is difficult for the lens to have the exit pupil position and principal point (Principal Point) closer to the imaging plane. Therefore, the angle of CRA must be at least greater than 25 degrees, so the best effect range is 25°< CRA <40°, which can allow the lens to have the exit pupil position and the main point closer to the imaging surface to effectively shorten the lens Back focus and maintain miniaturization.

Sixth embodiment:

Please refer to FIGS. 6A to 6D, where FIG. 6A shows a schematic diagram of a camera lens according to a sixth embodiment of the present invention, and FIGS. 6B to 6D are the field curvature, distortion, and longitudinal images of the sixth embodiment, respectively, in that order. Difference chart. The sixth embodiment is a structure of six lenses (that is, L1 to L6), the second lens L2 is a lens whose object side surface is convex at the low optical axis, and the image side surface is concave at the low optical axis, and the fifth lens L5 It is a biconcave lens. Table 11 is a table of related parameters of each lens of the optical lens in FIG. 6A, and Table 12 is a table of related parameters of the aspherical surfaces of each lens in Table 11. Among them, the Petzval sum is 0.077, which is between -1 and 1. The f-number of the camera lens is 2.4, the effective focal length is 3.920mm, and the maximum effective diameter of the first lens L1 (that is, L 1 R 1 Rm ) is 11.66mm, so , Between 0.2 and 1. The Abbe coefficient of the fourth lens L4 is 56.1, and the Abbe coefficient of the fifth lens L5 is 21.5, so ( V 4 d - V 5 d )=34.6, ranging from 23 to 40. The distance between the edge of the L1R2 surface and the edge of the L2R1 surface in the optical axis direction is 0.53 mm, which is between 0 and 1 mm. The focal length of the third lens L3 is 4.552mm, so , Between 1 and 2.8. The central thickness value T2 of the second lens L2 is 4.701 mm, and the total lens length is 17.989 mm, so T2/TTL = 0.261, which is between 0.2 and 1, and TTL/f = 4.589, which is between 4.4 and 10. The CRA is 38.8 degrees, between 25 and 40 degrees. IH is 3.758mm, so , Between 2 and 4.5, and , Between 0.5 and 2.5. The Abbe coefficient of the first lens L1 is 75.1, and the Abbe coefficient of the third lens L3 is 32.7, so , Between 0.5 and 3.

If the value of T2/TTL in condition (5) is less than 0.2, it is difficult to achieve the objective of lens miniaturization. Therefore, the value of T2/TTL must be at least greater than 0.2, so the best effect range is 1> >0.2, which meets the requirements of the best lens miniaturization.

The formula in accordance with the present invention is 1 2.8, 40 ( V 4 d - V 5 d ) 23, 3> >0.5, 4< <10, 25°< CRA <40°, 1> >0.2 is the center, and the numerical value of the embodiment of the present invention also falls within the range of the remaining formulas. Formula 1 28. It can help to achieve a better balance between optical characteristics and lens manufacturability. Formula 4< <10 and 1> >0.2, can help the lens to achieve miniaturization. Formula 40 ( V 4 d - V 5 d ) 23 and 3> >0.5, can make achromatic performance better. The formula 25°< CRA <40° can provide the lens with the exit pupil position and main point closer to the imaging surface, to effectively shorten the back focal length of the lens and maintain miniaturization.

Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Those with ordinary knowledge in the technical field to which the present invention belongs can make various modifications and changes without departing from the spirit and scope of the present invention. Retouching, therefore, the protection scope of the present invention shall be subject to the scope defined in the appended patent application.

Claims (10)

An imaging lens, which sequentially includes on the optical axis from the object side to the image side: a first lens, which is a meniscus lens with negative refractive power; a second lens, which is a lens with negative refractive power, and its image The side surface is concave; a third lens, which is a lens with positive power, whose image side surface is convex; a fourth lens, which is a lens with positive power; and a fifth lens, which is of negative power The lens has a concave surface on the object side; where the imaging lens satisfies the following conditional expression: 1> >0.2 where T 2 is the center thickness of the second lens, and TTL is the total length of the camera lens. An imaging lens, which sequentially includes on the optical axis from the object side to the image side: a first lens, which is a meniscus lens with negative refractive power; a second lens, which is a lens with negative refractive power, and its image The side surface is concave; a third lens, which is a lens with positive power, whose image side surface is convex; an aperture; a fourth lens, which is a lens with positive power; and a fifth lens, which is Negative dioptric double concave lens. The optical lens as described in item 1 or 2 of the patent application, wherein the object-side surface of the first lens is convex and the image-side surface is concave, the object-side surface of the second lens is concave, and the object of the third lens The side surface is convex, and the fourth lens is a biconvex lens. The optical lens as described in item 1 or 2 of the patent application scope further includes: a sixth lens disposed between the fifth lens and an imaging plane, the sixth lens is a lens with negative refractive power, and the object side The surface is convex, and the image-side surface is concave. The optical lens as described in item 4 of the patent application range, wherein the object-side surface of the second lens is convex, and the image-side surface of the fifth lens is convex. The optical lens as described in item 1 or 2 of the patent application scope, wherein the camera lens satisfies the following conditional expression: 25°< CRA <40°; where n1 is the refractive index of the first lens, n2 is the refractive index of the second lens, n3 is the refractive index of the third lens, n4 is the refractive index of the fourth lens, n5 Is the refractive index of the fifth 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, and f5 is the fifth The focal length of the lens, CRA , the maximum angle at which the chief rays enter the imaging plane. The optical lens as described in item 1 or 2 of the patent application scope, wherein the camera lens satisfies the following conditional expression: 0.2 1; 4.5> >2;2.5> >0.5; where f is the effective focal length of the camera lens, L 1 is the maximum effective diameter of the first lens, IH is the maximum imaging height of the imaging lens in the imaging plane, and T 2 is the central thickness value of the second lens. The optical lens as described in item 1 or 2 of the patent application scope, wherein the camera lens satisfies the following conditional expression: 3> >0.5; 40 ( V 4 d - V 5 d ) 23; where V 1 d is the Abbe number of the first lens, V 3 d is the Abbe number of the third lens, V 4 d is the Abbe number of the fourth lens, and V 5 d is The Abbe coefficient of the fifth lens. The optical lens as described in item 1 or 2 of the patent application range, wherein the distance between the edge of the image-side surface of the first lens and the edge of the object-side surface of the second lens in the optical axis direction is between 0 and 1 mm between. The optical lens as described in item 1 or 2 of the patent application scope, wherein the camera lens satisfies the following conditional expression: 1 2.8; 4< <10; where f3 is the focal length of the third lens, f is the effective focal length of the camera lens, and TTL is the total length of the camera lens.