TWI852721B - Lens assembly - Google Patents

Abstract

A lens assembly includes a first lens group, a second lens group, and a third lens group. The first lens group is with positive refractive power. The second lens group is with negative refractive power and includes at least two lenses. The third lens group is with positive refractive power and includes a 3-1 lens, a 3-2 lens, a 3-3 lens, and a 3-4 lens. The first lens group, the second lens group, and the third lens group are arranged in order from an object side to an image side along an optical axis. The 3-1 lens, the 3-2 lens, the 3-3 lens, and the 3-4 lens are arranged in order from the object side to the image side along the optical axis. The 3-1 lens is a biconvex lens with positive refractive power and includes a convex surface facing the object side and another convex surface facing the image side. The 3-3 lens includes a concave surface facing the image side. The two lenses closest to the image side in the second lens group or the third lens group are meniscus lenses.

Description

Imaging lens (75)

The present invention relates to an imaging lens.

Today's high-resolution imaging lenses often have a long total lens length and a large size, which can no longer meet the application requirements of today's drones. Therefore, another imaging lens with a new structure is needed to meet the requirements of miniaturization and high resolution at the same time.

In view of this, the main purpose of the present invention is to provide an imaging lens with a shorter total length and higher resolution, but still with good optical performance.

The present invention provides an imaging lens including a first lens group, a second lens group and a third lens group. The first lens group has positive refractive power. The second lens group has negative refractive power and includes at least two lenses. The third lens group has positive refractive power and includes a 3-1 lens, a 3-2 lens, a 3-3 lens and a 3-4 lens. The first lens group, the second lens group and the third lens group are arranged in sequence from an object side to an image side along an optical axis. The 3-1 lens, the 3-2 lens, the 3-3 lens and the 3-4 lens are arranged in sequence from the object side to the image side along the optical axis. The 3-1 lens is a biconvex lens with positive refractive power and includes a convex surface facing the object side and another convex surface facing the image side. The 3-3 lens includes a concave surface facing the image side. The two lenses closest to the image side in the second lens group or the third lens group are meniscus lenses.

The refractive powers of adjacent lenses in the second lens group or the third lens group are opposite.

The present invention provides another imaging lens including a first lens group, a second lens group and a third lens group. The first lens group has positive refractive power. The second lens group has negative refractive power. The third lens group has positive refractive power. The first lens group, the second lens group and the third lens group are arranged in sequence from an object side to an image side along an optical axis. The lens closest to the object side in the third lens group is a biconvex lens with positive refractive power, and includes a convex surface facing the object side and another convex surface facing the image side. The second lens group or the third lens group includes a plurality of lenses, and the refractive powers of adjacent lenses in the lenses are opposite.

The third lens group includes a 3-1 lens, a 3-2 lens, a 3-3 lens and a 3-4 lens arranged in sequence from the object side to the image side along the optical axis; the 3-3 lens includes a concave surface facing the image side; in the second lens group or the third lens group, the two lenses closest to the image side are meniscus lenses.

The second lens group includes a 2-1 lens, a 2-2 lens and a 2-3 lens; one of the 2-1 lens, the 2-2 lens and the 2-3 lens is a biconcave lens and the other two are meniscus lenses; the 2-1 lens and the 2-3 lens have the same refractive power, and the 2-1 lens and the 2-2 lens have opposite refractive powers; and the refractive power of the lens closest to the object side in the second lens group is opposite to the refractive power of the lens closest to the object side in the third lens group.

The object side surface of the lens closest to the object side in the second lens group is the same as its image side surface; the image side surfaces of adjacent lenses in the first lens group or the second lens group are the same; and the second lens group and the third lens group include a total of five meniscus lenses.

The first lens group includes a 1-1 lens, a 1-2 lens, and a 1-3 lens arranged in sequence from the object side to the image side along the optical axis; the second lens group includes a 2-1 lens, a 2-2 lens, and a 2-3 lens arranged in sequence from the object side to the image side along the optical axis; the 1-2 lens includes a concave The 2-1 lens includes a concave surface facing the object side; the 2-2 lens is a meniscus lens with positive refractive power, and includes a convex surface facing the object side and a concave surface facing the image side; and the 2-3 lens is a meniscus lens with negative refractive power, and includes a convex surface facing the object side and a concave surface facing the image side.

The 1-1 lens is a meniscus lens with negative refractive power, and includes a convex surface facing the object side and a concave surface facing the image side; the 1-2 lens is a meniscus lens with positive refractive power, and further includes a convex surface facing the object side; the 1-3 lens is a meniscus lens with positive refractive power, and includes a convex surface facing the object side and a concave surface facing the image side; the 2-1 lens is a biconcave lens with negative refractive power. power, and further includes another concave surface facing the image side; the 3-2 lens is a meniscus lens with negative refractive power, and includes a convex surface facing the object side and a concave surface facing the image side; the 3-3 lens is a meniscus lens with positive refractive power, and further includes a convex surface facing the object side; and the 3-4 lens is a meniscus lens with negative refractive power, and includes a concave surface facing the object side and a convex surface facing the image side.

It may further include an aperture disposed between the second lens group and the third lens group, and the second lens group may be movable along the optical axis for focusing.

The imaging lens of the present invention can meet at least one of the following conditions: -0.76<fG2/f<-0.6; 0.8<fG3/f<1.8; 3.6<β2<6; 1.6<fG3/fG1<2.2; 0.75<TTL/fG3<1.05; 4.5<TTL/BFL<8; 0.7<f/TTL<0.9; 3.6<f/BFL<5.5; 0.4<T11ST/TSTIMA<0.7; 0.53<fG1/f<0.82; wherein f is an effective focal length of the imaging lens, fG1 is the first lens fG2 is an effective focal length of the second lens group, fG3 is an effective focal length of the third lens group, TTL is a distance from an object side surface of the lens closest to the object side to an imaging plane on the optical axis, BFL is a distance from an image side surface of the lens closest to the image side to the imaging plane on the optical axis, T11ST is a distance from the object side surface of the lens closest to the object side to the aperture on the optical axis, TSTIMA is a distance from an aperture to the imaging plane on the optical axis, β2 is a lateral magnification of the second lens group when an object is located at infinite distance.

In order to make the above-mentioned purposes, features, and advantages of the present invention more clearly understood, the following specifically cites preferred embodiments and provides detailed descriptions with the accompanying drawings.

3, 4: Imaging lens

LG31, LG41: First lens group

LG32, LG42: Second lens group

LG33, LG43: The third lens group

3L1-1, 4L1-1 1-1: Lens

3L1-2, 4L1-2 1-2: Lens

3L1-3, 4L1-3 1-3: Lens

3L2-1, 4L2-1 2-1: Lens

3L2-2, 4L2-2: 2-2 lens

3L2-3, 4L2-3: 2-3 lens

3L3-1, 4L3-1: 3-1 lens

3L3-2, 4L3-2: 3-2 lens

3L3-3, 4L3-3: 3-3 lens

3L3-4, 4L3-4: 3-4 lens

ST3, ST4: aperture

OF3, OF4: filter

CG3, CG4: Protective glass

IMA3, IMA4: Imaging surface

OA3, OA4: optical axis

S31, S41:1-1 Lens object side

S32, S42: 1-1 Lens image side view

S33, S43:1-2 Lens object side

S34, S44: 1-2 Lens image side

S35, S45: 1-3 Lens object side

S36, S46: 1-3 Lens image side view

S37, S47: 2-1 Lens object side

S38, S48: 2-1 lens image side

S39, S49: 2-2 Lens object side

S310, S410: 2-2 lens image side

S311, S411: 2-3 Lens object side

S312, S412: 2-3 lens image side

S313, S413: aperture surface

S314, S414:3-1 Lens object side

S315, S415: 3-1 Lens image side view

S316, S416:3-2 Object side of lens

S317, S417: 3-2 Lens image side view

S318, S418:3-3 Lens object side

S319, S419: 3-3 Lens image side view

S320, S420: 3-4 lens object side

S321, S421: 3-4 lens image side

S322, S422: Object side of filter

S323, S423: filter image side

S324, S424: Protect the side of the glass

S325, S425: Protective glass image side

Figure 1 is a schematic diagram of the lens configuration and optical path of the fifth embodiment of the imaging lens of the present invention.

Figure 2 is a field curvature diagram of the fifth embodiment of the imaging lens of the present invention.

Figure 3 is a distortion diagram of the fifth embodiment of the imaging lens of the present invention.

Figure 4 is a diagram of the modulation transfer function according to the fifth embodiment of the imaging lens of the present invention.

Figure 5 is a diagram of the Y field of view modulation conversion function according to the fifth embodiment of the imaging lens of the present invention.

Figure 6 is a Through Focus Modulation Transfer Function diagram of the fifth embodiment of the imaging lens of the present invention.

Figure 7 is a schematic diagram of the lens configuration and optical path of the sixth embodiment of the imaging lens of the present invention.

Figure 8 is a field curvature diagram according to the sixth embodiment of the imaging lens of the present invention.

Figure 9 is a distortion diagram of the sixth embodiment of the imaging lens of the present invention.

Figure 10 is a modulation transfer function diagram according to the sixth embodiment of the imaging lens of the present invention.

Figure 11 is a diagram of the Y field of view modulation conversion function according to the sixth embodiment of the imaging lens of the present invention.

Figure 12 is a defocus modulation conversion function diagram of the sixth embodiment of the imaging lens of the present invention.

The present invention provides an imaging lens, comprising: a first lens group, the first lens group having positive refractive power; a second lens group, the second lens group having negative refractive power; and a third lens group, the third lens group having positive refractive power; wherein the first lens group, the second lens group and the third lens group are arranged in sequence from an object side to an image side along an optical axis.

The imaging lens of the first embodiment of the present invention is according to the first paragraph of [Implementation Method], wherein the first lens group includes a lens, the lens has positive refractive power, and can be a biconvex lens, a plano-convex lens, or a meniscus-shaped concave-convex or convex-concave lens; the second lens group includes two lenses, the lenses have positive or negative refractive power, but not all of them are positive refractive power, and the lenses can be a biconvex lens, a biconcave lens, a plano-convex lens, a plano-concave lens, or a meniscus-shaped concave-convex or convex-concave lens, but not all of them are biconvex lenses or plano-convex lenses; the third lens group includes a 3-1 lens, a 3-2 lens, a 3-3 lens, and a 3-4 lens; the 3-1 lens is the lens closest to the object side in the third lens group and is a biconvex lens with positive refractive power; the 3-2 lens, the 3-3 lens and the 3-4 lens can have positive or negative refractive power; the 3-2 lens and the 3-4 lens can be biconvex lenses, biconcave lenses, plano-convex lenses, plano-concave lenses or meniscus-shaped concave-convex or convex-concave lenses, and the 3-3 lens includes a concave surface facing the image side and the other surface can be a convex surface, a plane surface or a concave surface facing the object side; the two lenses closest to the image side in the second lens group and/or the third lens group are meniscus lenses, and this design helps to reduce field curvature. During imaging, the light from the object side is finally imaged on an imaging surface. The first embodiment of the present invention can achieve basic operation through the above design.

The imaging lens of the second embodiment of the present invention is according to the first paragraph of [Implementation Method], wherein the first lens group includes a lens, the lens has positive refractive power, and can be a biconvex lens, a plano-convex lens, or a meniscus-shaped concave-convex or convex-concave lens; the second lens group includes two lenses, the lenses have positive or negative refractive power, but not all of them are positive refractive power, and the lenses can be biconvex lenses, biconcave lenses, plano-convex lenses, plano-concave lenses, or meniscus-shaped concave-convex or convex-concave lenses, but not all of them are biconvex lenses or plano-convex lenses; and the third lens group includes two lenses, the lenses have positive or negative refractive power, but not all of them are negative refractive power, and the The lenses may be biconvex lenses, biconcave lenses, plano-convex lenses, plano-concave lenses, or meniscus-shaped concave-convex or convex-concave lenses, but not all of them may be biconcave lenses or plano-concave lenses; wherein the lens of the third lens group closest to the object side is a biconvex lens with positive refractive power, and the lenses of the second lens group and/or the third lens group are/is not biconvex. The refractive powers of adjacent lenses are opposite, that is, the refractive powers of the lenses of the second lens group are one positive and one negative, or the refractive powers of the lenses of the third lens group are one positive and one negative, or the refractive powers of the lenses of the second lens group and the third lens group are negative positive negative positive or positive negative positive negative from the object side to the image side. When imaging, the light from the object side is finally imaged on an imaging plane. The second embodiment of the present invention can achieve basic operation through the above design.

The imaging lens of the third embodiment of the present invention is according to the first paragraph of [Implementation Method], wherein the first lens group includes a 1-1 lens, a 1-2 lens and a 1-3 lens arranged in sequence from the object side to the image side along the optical axis; the 1-1 lens, the 1-2 lens and the 1-3 lens are meniscus lenses (concave-convex or convex-concave lenses) and have the same surface shape facing the object side, and the refractive power can be positive or negative, and the refractive power of the 1-2 lens and the 1-3 lens is the same, and the refractive power of the 1-1 lens and the 1-2 lens is opposite. The second lens group includes a 2-1 lens, a 2-2 lens, and a 2-3 lens arranged in sequence from the object side to the image side along the optical axis. Among the 2-1 lens, the 2-2 lens, and the 2-3 lens, one is a double concave lens and the other two are meniscus lenses (concave-convex or convex-concave lenses). The two meniscus lenses have the same surface shape facing the object side, and the refractive power can be positive or negative. The refractive power of the 2-1 lens and the 2-3 lens is the same, and the refractive power of the 2-1 lens and the 2-2 lens is opposite. The third lens group includes a 3-1 lens, a 3-2 lens, a 3-3 lens, and a 3-4 lens arranged in order from the object side to the image side along the optical axis. The 3-1 lens is a biconvex lens with positive refractive power. The 3-2 lens, the 3-3 lens, and the 3-4 lens are meniscus lenses (concave-convex or convex-concave lenses). The refractive power can be positive or negative. The refractive power of the 3-2 lens and the 3-4 lens is the same, and the refractive power of the 3-2 lens and the 3-3 lens is opposite. The second lens group and the third lens group have a total of five meniscus lenses. The image side surfaces of the 1-1 lens, the 1-2 lens, and the 1-3 lens are the same, or the image side surfaces of the 2-1 lens, the 2-2 lens, and the 2-3 lens are the same. When imaging, the light from the object side is finally imaged on an imaging surface. The third embodiment of the present invention can achieve basic operation through the above design.

The imaging lens of the fourth embodiment of the present invention is according to the first paragraph of [Implementation Method], wherein lens 1-1 is a meniscus lens with negative refractive power, its object side surface is convex, and its image side surface is concave. Lens 1-2 is a meniscus lens with positive refractive power, its object side surface is convex, and its image side surface is concave. Lens 1-3 is a meniscus lens with positive refractive power, its object side surface is convex, and its image side surface is concave. Lens 2-1 is a biconcave lens with negative refractive power, its object side surface and image side surface are concave. Lens 2-2 is a meniscus lens with positive refractive power, its object side surface is convex, and its image side surface is concave. The 2-3 lens is a meniscus lens with negative refractive power, its object side surface is convex, and its image side surface is concave. The 3-1 lens is a biconvex lens with positive refractive power, its object side surface is convex, and its image side surface is convex. The 3-2 lens is a meniscus lens with negative refractive power, its object side surface is convex, and its image side surface is concave. The 3-3 lens is a meniscus lens with positive refractive power, its object side surface is convex, and its image side surface is concave. The 3-4 lens is a meniscus lens with negative refractive power, its object side surface is concave, and its image side surface is convex. When imaging, the light from the object side finally forms an image on an imaging plane. The fourth embodiment of the present invention can achieve basic operation through the above design.

In addition, in another embodiment, the imaging lens of each of the above embodiments can further reduce chromatic aberration and improve resolution by satisfying the condition 85<VdG1P<90, where VdG1P is an average Abbe coefficient of the positive refractive power lens in the first lens group, and basic operation can be achieved by satisfying this condition. In another embodiment, the imaging lens can further improve resolution by satisfying the condition -0.76<fG2/f<-0.6, where fG2 is an effective focal length of the second lens group, and f is an effective focal length of the imaging lens, and basic operation can be achieved by satisfying this condition. In yet another embodiment, the sensitivity can be effectively reduced by further satisfying the condition 0.8<fG3/f<1.8, where fG3 is an effective focal length of the third lens group and f is an effective focal length of the imaging lens, and basic operation can be achieved by satisfying this condition. In yet another embodiment, the focusing capability can be effectively improved by further satisfying the condition 1.6<fG3/fG1<2.2, where fG3 is an effective focal length of the third lens group and fG1 is an effective focal length of the first lens group, and basic operation can be achieved by satisfying this condition. In yet another embodiment, the total length of the lens can be effectively shortened by further satisfying the condition 0.75<TTL/fG3<1.05, where fG3 is an effective focal length of the third lens group and TTL is a distance on the optical axis from the object side surface of the lens closest to the object side of the imaging lens to the imaging surface. Basic actuation can be achieved by satisfying this condition. In yet another embodiment, the back focal length can be effectively increased and the production yield of the imaging lens can be improved by further satisfying the condition 4.5<TTL/BFL<8, where TTL is the distance from the object side surface of the lens closest to the object side of the imaging lens to the imaging plane on the optical axis, and BFL is the distance from the image side surface of the lens closest to the image side of the imaging lens to the imaging plane on the optical axis. Basic operation can be achieved by satisfying this condition. In yet another embodiment, the total length of the lens can be effectively shortened by further satisfying the condition 0.7<f/TTL<0.9, where TTL is the distance between the object side of the lens closest to the object side and the imaging plane on the optical axis, and f is an effective focal length of the imaging lens. Basic operation can be achieved by satisfying this condition. In yet another embodiment, the back focal length can be effectively increased and the production yield of the imaging lens can be improved by further satisfying the condition 3.6<f/BFL<5.5, where BFL is the distance between the image side of the lens closest to the image side and the imaging plane on the optical axis, and f is an effective focal length of the imaging lens. Basic operation can be achieved by satisfying this condition. In yet another embodiment, the production yield of the imaging lens can be effectively improved by further satisfying the condition 0.4<T11ST/TSTIMA<0.7, where T11ST is the distance from the object side of the lens closest to the object side of the imaging lens to an aperture on the optical axis, and TSTIMA is the distance from the aperture in the imaging lens to the imaging surface on the optical axis. Basic operation can be achieved by satisfying this condition. In yet another embodiment, the resolution can be effectively improved by further satisfying the condition 0.53<fG1/f<0.82, where fG1 is an effective focal length of the first lens group, and f is an effective focal length of the imaging lens. Basic operation can be achieved by satisfying this condition.

Please refer to Table 1, Table 2, Table 4 and Table 5 below, wherein Table 1 and Table 4 are tables of relevant parameters of each lens of the fifth embodiment to the sixth embodiment of the imaging lens according to the present invention, and Table 2 and Table 5 are tables of relevant parameters of the aspherical surface of the aspherical lens in Table 1 and Table 4, respectively.

Figures 1 and 7 are schematic diagrams of lens configuration and optical paths of the fifth and sixth embodiments of the imaging lens of the present invention, respectively. Among them, the 1-1 lens 3L1-1 and 4L1-1 are meniscus lenses with negative refractive power, and their object side surfaces S31 and S41 are convex, and the image side surfaces S32 and S42 are concave. The object side surfaces S31 and S41 and the image side surfaces S32 and S42 are all spherical surfaces. The 1-2 lens 3L1-2 and 4L1-2 are meniscus lenses with positive refractive power, and their object side surfaces S33 and S43 are convex, and the image side surfaces S34 and S44 are concave. The object side surfaces S33 and S43 and the image side surfaces S34 and S44 are all spherical surfaces. 1-3 lenses 3L1-3 and 4L1-3 are meniscus lenses with positive refractive power, whose object side surfaces S35 and S45 are convex, and image side surfaces S36 and S46 are concave. Object side surfaces S35 and S45 and image side surfaces S36 and S46 are all aspherical surfaces.

The 2-1 lenses 3L2-1 and 4L2-1 are biconcave lenses with negative refractive power, and their object side surfaces S37 and S47 are concave, and the image side surfaces S38 and S48 are concave. The object side surfaces S37 and S47 and the image side surfaces S38 and S48 are all spherical surfaces. The 2-2 lenses 3L2-2 and 4L2-2 are meniscus lenses with positive refractive power, and their object side surfaces S39 and S49 are convex, and the image side surfaces S310 and S410 are concave. The object side surfaces S39 and S49 and the image side surfaces S310 and S410 are all spherical surfaces. 2-3 Lenses 3L2-3 and 4L2-3 are meniscus lenses with negative refractive power. Their object side surfaces S311 and S411 are convex, and their image side surfaces S312 and S412 are concave. Both the object side surfaces S311 and S411 and the image side surfaces S312 and S412 are spherical surfaces.

3-1 lenses 3L3-1 and 4L3-1 are biconvex lenses with positive refractive power, and their object side surfaces S314 and S414 are convex, and image side surfaces S315 and S415 are convex. Object side surfaces S314 and S414 and image side surfaces S315 and S415 are all spherical surfaces. 3-2 lenses 3L3-2 and 4L3-2 are meniscus lenses with negative refractive power, and their object side surfaces S316 and S416 are convex, and image side surfaces S317 and S417 are concave. Object side surfaces S316 and S416 and image side surfaces S317 and S417 are all spherical surfaces. 3-3 lenses 3L3-3 and 4L3-3 are meniscus lenses with positive refractive power, whose object side surfaces S318 and S418 are convex, and whose image side surfaces S319 and S419 are concave. Both the object side surfaces S318 and S418 and the image side surfaces S319 and S419 are spherical surfaces. 3-4 lenses 3L3-4 and 4L3-4 are meniscus lenses with negative refractive power, whose object side surfaces S320 and S420 are concave, and whose image side surfaces S321 and S421 are convex. Both the object side surfaces S320 and S420 and the image side surfaces S321 and S421 are spherical surfaces.

In addition, the imaging lenses 3 and 4 can optimize the performance of the imaging lenses by satisfying at least one or all of the following conditions (1) to (11). The optimized performance is as described in the sixth paragraph of [Implementation Method], so it will not be repeated here:

85<VdG1P<90; (1)

-0.76<fG2/f<-0.6； (2)

0.8<fG3/f<1.8； (3)

3.6<β2<6; (4)

1.6<fG3/fG1<2.2; (5)

0.75<TTL/fG3<1.05; (6)

4.5<TTL/BFL<8; (7)

0.7<f/TTL<0.9; (8)

3.6<f/BFL<5.5; (9)

0.4<T11ST/TSTIMA<0.7; (10)

0.53<fG1/f<0.82; (11)

Wherein, VdG1P is an average Abbe coefficient of a lens with positive refractive power in the first lens group LG31 and LG41 in the fifth to sixth embodiments, f is an effective focal length of the imaging lenses 3 and 4 in the fifth to sixth embodiments, fG1 is an effective focal length of the first lens group LG31 and LG41 in the fifth to sixth embodiments, fG2 is an effective focal length of the second lens group LG32 and LG42 in the fifth to sixth embodiments, fG3 is an effective focal length of the third lens group LG33 and LG43 in the fifth to sixth embodiments, TTL is the distance from the object side surface S31 and S41 of the lens 3L1-1 and 4L1-1 closest to the object side to the imaging surface IMA3 and IMA4 on the optical axis OA3 and OA4 in the fifth to sixth embodiments. 4, BFL is a distance between the image side surface S321, S421 of the lens 3L3-4, 4L3-4 closest to the image side and the imaging surface IMA3, IMA4 on the optical axis OA3, OA4 in the fifth to sixth embodiments, T11ST is a distance between the object side surface S31, S421 of the lens 3L1-1, 4L1-1 closest to the object side in the fifth to sixth embodiments, 1 is a distance from aperture ST3, ST4 on optical axis OA3, OA4, TSTIMA is a distance from aperture ST3, ST4 to imaging plane IMA3, IMA4 on optical axis OA3, OA4 in the fifth to sixth embodiments, β2 is a lateral magnification of the second lens group LG32, LG42 when the object is at infinite distance in the fifth to sixth embodiments. The imaging lens 3, 4 can effectively shorten the total length of the lens, effectively improve the resolution, and effectively correct the aberration.

The fifth embodiment of the imaging lens of the present invention is described in detail. Referring to FIG. 1, the imaging lens 3 includes a first lens group LG31, a second lens group LG32, an aperture ST3, a third lens group LG33, a filter OF3, and a protective glass CG3 arranged in sequence from an object side to an image side along an optical axis OA3. The first lens group LG31 has positive refractive power, and includes a 1-1 lens 3L1-1, a 1-2 lens 3L1-2, and a 1-3 lens 3L1-3 arranged in sequence from an object side to an image side along the optical axis OA3. The second lens group LG32 has negative refractive power, and includes a 2-1 lens 3L2-1, a 2-2 lens 3L2-2, and a 2-3 lens 3L2-3 arranged in sequence from the object side to the image side along the optical axis OA3. The third lens group LG33 has positive refractive power, and includes a 3-1 lens 3L3-1, a 3-2 lens 3L3-2, a 3-3 lens 3L3-3, and a 3-4 lens 3L3-4 arranged in sequence from the object side to the image side along the optical axis OA3. When imaging, the light from the object side is finally imaged on an imaging surface IMA3. According to paragraphs 7 to 10 of [Implementation Method], the object side surface S322 and the image side surface S323 of the filter OF3 are both planes; the object side surface S324 and the image side surface S325 of the protective glass CG3 are both planes; by using the above-mentioned lens and the design that satisfies at least one of the conditions (1) to (11), the imaging lens 3 can effectively shorten the total length of the lens, effectively improve the resolution, and effectively correct the aberration.

Table 1 is a table of relevant parameters of each lens of the imaging lens 3 in Figure 1.

The aspheric surface concavity z of the aspheric lens in Table 1 is obtained by the following formula:

z=ch ² /{1+[1-(k+1)c ² h ² ] ^1/2 }+Ah ⁴ +Bh ⁶ +Ch ⁸ +Dh ¹⁰ +Eh ¹² +Fh ¹⁴

Where: c: curvature; h: vertical distance from any point on the lens surface to the optical axis; k: cone coefficient; A~F: aspheric coefficient.

Table 2 is a table of relevant parameters of the aspheric surface of the aspheric lens in Table 1.

Table 3 shows the relevant parameter values of the imaging lens 3 of the fifth embodiment and the calculated values of the corresponding conditions (1) to (11). It can be seen from Table 3 that the imaging lens 3 of the fifth embodiment can meet the requirements of conditions (1) to (11).

In addition, the optical performance of the imaging lens 3 of the fifth embodiment can also meet the requirements. As can be seen from FIG. 2, the field curvature of the imaging lens 3 of the fifth embodiment is between -0.09 mm and 0.06 mm. As can be seen from FIG. 3, the distortion of the imaging lens 3 of the fifth embodiment is between 0% and 2.5%. As can be seen from FIG. 4, the modulation transfer function value of the imaging lens 3 of the fifth embodiment is between 0.62 and 1.0. As can be seen from FIG. 5, the Y field of view modulation transfer function value of the imaging lens 3 of the fifth embodiment is between 0.62 and 0.95. As can be seen from FIG. 6, the modulation transfer function value of the imaging lens 3 of the fifth embodiment is between 0.02 and 0.95 when the focus offset is between -0.2 mm and 0.2 mm. It is obvious that the field curvature and distortion of the imaging lens 3 of the fifth embodiment can be effectively corrected, and the lens resolution can also meet the requirements, thereby obtaining better optical performance.

The sixth embodiment of the imaging lens of the present invention is described in detail. Referring to FIG. 7 , the imaging lens 4 includes a first lens group LG41, a second lens group LG42, an aperture ST4, a third lens group LG43, a filter OF4, and a protective glass CG4 arranged in sequence from an object side to an image side along an optical axis OA4. The first lens group LG41 has positive refractive power, and includes a 1-1 lens 4L1-1, a 1-2 lens 4L1-2, and a 1-3 lens 4L1-3 arranged in sequence from an object side to an image side along an optical axis OA4. The second lens group LG42 has negative refractive power. The second lens group LG42 includes a 2-1 lens 4L2-1, a 2-2 lens 4L2-2, and a 2-3 lens 4L2-3 arranged in sequence from the object side to the image side along the optical axis OA4. The third lens group LG43 has positive refractive power. The third lens group LG43 includes a 3-1 lens 4L3-1, a 3-2 lens 4L3-2, a 3-3 lens 4L3-3, and a 3-4 lens 4L3-4 arranged in sequence from the object side to the image side along the optical axis OA4. When imaging, the light from the object side is finally imaged on an imaging surface IMA4. According to paragraphs 7 to 10 of [Implementation Method], the object side surface S422 and the image side surface S423 of the filter OF4 are both planes; the object side surface S424 and the image side surface S425 of the protective glass CG4 are both planes; by using the above-mentioned lens and the design that satisfies at least one of the conditions (1) to (11), the imaging lens 4 can effectively shorten the total length of the lens, effectively improve the resolution, and effectively correct the aberration.

Table 4 is a table of relevant parameters of each lens of the imaging lens 4 in Figure 7.

The definition of the concavity z of the aspheric surface of each lens in Table 4 is the same as the definition of the concavity z of the aspheric surface of each lens in Table 1 in the fifth embodiment, and will not be elaborated here. Table 5 is a table of relevant parameters of the aspheric surface of the aspheric lens in Table 4.

Table 6 shows the relevant parameter values of the imaging lens 4 of the sixth embodiment and the calculated values corresponding to conditions (1) to (11). It can be seen from Table 6 that the imaging lens 4 of the sixth embodiment can meet the requirements of conditions (1) to (11).

In addition, the optical performance of the imaging lens 4 of the sixth embodiment can also meet the requirements. As shown in FIG. 8, the field curvature of the imaging lens 4 of the sixth embodiment is between -0.21 mm and 0.06 mm. As shown in FIG. 9, the distortion of the imaging lens 4 of the sixth embodiment is between 0% and 2.5%. As shown in FIG. 10, the modulation transfer function value of the imaging lens 4 of the sixth embodiment is between 0.66 and 1.0. As shown in FIG. 11, the Y field modulation transfer function value of the imaging lens 4 of the sixth embodiment is between 0.67 and 0.95. As shown in FIG. 12, when the focus offset of the imaging lens 4 of the sixth embodiment is between -0.2 mm and 0.2 mm, the modulation transfer function value is between 0.00 and 0.95. It is obvious that the field curvature and distortion of the imaging lens 4 of the sixth embodiment can be effectively corrected, and the lens resolution can also meet the requirements, thereby obtaining better optical performance.

In the above embodiments 1 to 6, the positive refractive power of the first lens group and the aspherical lenses of lenses 1-3 are helpful for resolution. In the above embodiments 1 to 6, the design of the image side surfaces of the lenses in the first lens group and/or the second lens group being concave helps to shorten the total length of the lens. In any of the above embodiments 1 to 6, in another other embodiment, the second lens group is a focusing lens group, which can be moved on the optical axis for focusing. This design is matched with the refractive power of the adjacent lenses in the second lens group and/or the third lens group being opposite, or with the lenses closest to the object side of the second lens group and the third lens group being positive refractive, which helps to match the focus sensitivity with the moving range.

Although the present invention has been disclosed as above in the preferred implementation mode, it is not intended to limit the present invention. Anyone familiar with this technology can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope of the attached patent application.

3: Imaging lens

LG31: First lens group

LG32: Second lens group

LG33: The third lens group

3L1-1 1-1: Lens

3L1-2 1-2: Lens

3L1-3 1-3: Lens

3L2-1 2-1: Lens

3L2-2 2-2: Lens

3L2-3 2-3: Lens

3L3-1 3-1: Lens

3L3-2 3-2: Lens

3L3-3 3-3: Lens

3L3-4 3-4: Lens

ST3: Aperture

OF3: Filter

CG3: Protective glass

IMA3: Imaging surface

OA3: Optical axis

S31 1-1: Object side of lens

S32 1-1: Lens image side

S33 1-2: Object side of lens

S34 1-2: Lens image side

S35 1-3: Object side of lens

S36 1-3: Lens image side

S37 2-1: Object side of lens

S38 2-1: Lens image side

S39 2-2: Object side of lens

S310 2-2: Lens image side view

S311 2-3: Object side of lens

S312 2-3: Lens image side

S314 3-1: Object side of lens

S315 3-1: Lens image side

S316 3-2: Object side of lens

S317 3-2: Lens image side

S318 3-3: Object side of lens

S319 3-3: Lens image side view

S320 3-4: Lens side

S321 3-4: Lens image side

S322: Object side of filter

S323: Filter image side

S324: Protect the side of the glass

S325: Protective glass image side

S313: Aperture surface

Claims (10)

An imaging lens comprises: a first lens group, the first lens group having positive refractive power; a second lens group, the second lens group having negative refractive power and including at least two lenses; and a third lens group, the third lens group having positive refractive power and including a 3-1 lens, a 3-2 lens, a 3-3 lens and a 3-4 lens; wherein the first lens group, the second lens group and the third lens group are arranged in sequence from an object side to an image side along an optical axis; wherein There are three lens groups with different refractive powers; the 3-1 lens, the 3-2 lens, the 3-3 lens and the 3-4 lens are arranged in sequence from the object side to the image side along the optical axis; the 3-1 lens is a biconvex lens with positive refractive power and includes a convex surface facing the object side and another convex surface facing the image side; the 3-3 lens includes a concave surface facing the image side; the two lenses closest to the image side in the second lens group and the third lens group are meniscus lenses. An imaging lens as described in Item 1 of the patent application, wherein the refractive powers of adjacent lenses in the second lens group or the third lens group are opposite. An imaging lens comprises: a first lens group, the first lens group having positive refractive power; a second lens group, the second lens group having negative refractive power; and a third lens group, the third lens group having positive refractive power; wherein the first lens group, the second lens group and the third lens group are arranged in sequence from an object side to an image side along an optical axis; wherein the lens group having refractive power There are three lens groups in total; the lens closest to the object side in the third lens group is a biconvex lens with positive refractive power, and includes a convex surface facing the object side and another convex surface facing the image side; the two lenses closest to the image side in the second lens group are meniscus lenses; the third lens group includes a plurality of lenses, and the refractive powers of adjacent lenses in the lenses are opposite. The imaging lens as described in item 3 of the patent application, wherein: the third lens group includes a 3-1 lens, a 3-2 lens, a 3-3 lens and a 3-4 lens arranged in sequence along the optical axis from the object side to the image side; the 3-3 lens includes a concave surface facing the image side; in the third lens group, the two lenses closest to the image side are meniscus lenses; and the second lens group includes a plurality of lenses, and the refractive powers of adjacent lenses in the lenses are opposite. An imaging lens comprises: a first lens group, the first lens group has positive refractive power; a second lens group, the second lens group has negative refractive power; and a third lens group, the third lens group has positive refractive power; wherein the first lens group, the second lens group and the third lens group are arranged in sequence from an object side to an image side along an optical axis; wherein there are three lens groups with refractive power in total; wherein the lens closest to the object side in the third lens group is a biconvex lens with positive refractive power and includes a convex surface facing the object side and another convex surface facing the image side; wherein the two lenses closest to the image side in the second lens group are meniscus-shaped Lenses; wherein the second lens group or the third lens group includes a plurality of lenses, and the refractive powers of adjacent lenses in the lenses are opposite; wherein the second lens group includes a 2-1 lens, a 2-2 lens, and a 2-3 lens; wherein one of the 2-1 lens, the 2-2 lens, and the 2-3 lens is a biconcave lens and the other two are meniscus lenses; wherein the refractive powers of the 2-1 lens and the 2-3 lens are the same, and the refractive powers of the 2-1 lens and the 2-2 lens are opposite; wherein the refractive power of the lens closest to the object side in the second lens group is opposite to the refractive power of the lens closest to the object side in the third lens group. An imaging lens comprises: a first lens group, the first lens group having positive refractive power; a second lens group, the second lens group having negative refractive power; and a third lens group, the third lens group having positive refractive power; wherein the first lens group, the second lens group and the third lens group are arranged in sequence from an object side to an image side along an optical axis; wherein there are three lens groups with refractive power in total; wherein the lens closest to the object side in the third lens group is a biconvex lens having positive refractive power and comprising a convex surface facing the object side with a and another convex surface facing the image side; wherein the two lenses closest to the image side in the second lens group are meniscus lenses; wherein the second lens group or the third lens group includes a plurality of lenses, and the refractive powers of adjacent lenses in the lenses are opposite; wherein the object side surface of the lens closest to the object side in the second lens group is the same as the image side surface; wherein the image side surfaces of adjacent lenses in the first lens group or the second lens group are the same; wherein the second lens group and the third lens group include a total of five meniscus lenses. An imaging lens comprises: a first lens group, the first lens group having positive refractive power; a second lens group, the second lens group having negative refractive power and including at least two lenses; and a third lens group, the third lens group having positive refractive power and including a 3-1 lens, a 3-2 lens, a 3-3 lens and a 3-4 lens; wherein the first lens group, the second lens group and the third lens group The three lens groups are arranged in sequence from an object side to an image side along an optical axis; there are three lens groups with refractive power; the 3-1 lens, the 3-2 lens, the 3-3 lens and the 3-4 lens are arranged in sequence from the object side to the image side along the optical axis; the 3-1 lens is a biconvex lens with positive refractive power and includes a convex surface facing the object side and another convex surface facing the image side; the 3-3 lens is a biconvex lens with positive refractive power and ... The lens includes a concave surface facing the image side; wherein the two lenses closest to the image side in the second lens group are meniscus lenses; wherein the first lens group includes a 1-1 lens, a 1-2 lens, and a 1-3 lens arranged in sequence along the optical axis from the object side to the image side; wherein the second lens group includes a 2-1 lens, a 2-2 lens, and a 1-3 lens arranged in sequence along the optical axis from the object side to the image side and a 2-3 lens; wherein the 1-2 lens includes a concave surface facing the image side; wherein the 2-1 lens includes a concave surface facing the object side; wherein the 2-2 lens is a meniscus lens having positive refractive power, and includes a convex surface facing the object side and a concave surface facing the image side; wherein the 2-3 lens is a meniscus lens having negative refractive power, and includes a convex surface facing the object side and a concave surface facing the image side. The imaging lens as described in item 7 of the patent application, wherein: the 1-1 lens is a meniscus lens having negative refractive power, and includes a convex surface facing the object side and a concave surface facing the image side; the 1-2 lens is a meniscus lens having positive refractive power, and further includes a convex surface facing the object side; the 1-3 lens is a meniscus lens having positive refractive power, and includes a convex surface facing the object side and a concave surface facing the image side; the 2-1 lens is The biconcave lens has negative refractive power and further includes another concave surface facing the image side; the 3-2 lens is a meniscus lens with negative refractive power and includes a convex surface facing the object side and a concave surface facing the image side; the 3-3 lens is a meniscus lens with positive refractive power and further includes a convex surface facing the object side; and the 3-4 lens is a meniscus lens with negative refractive power and includes a concave surface facing the object side and a convex surface facing the image side. The imaging lens described in any one of items 1 to 4, 7 and 8 of the patent application scope further includes an aperture disposed between the second lens group and the third lens group, and the second lens group can move along the optical axis for focusing. An imaging lens as described in any one of items 1 to 4, 7 and 8 of the patent application, wherein the imaging lens satisfies at least one of the following conditions: -0.76<fG2/f<-0.6; 0.8<fG3/f<1.8; 3.6<β2<6; 1.6<fG3/fG1<2.2; 0.75<TTL/fG3<1.05; 4.5<TTL/BFL<8; 0.7<f/TTL<0.9; 3.6<f/BFL<5.5; 0.4<T11ST/TSTIMA<0.7; 0.53<fG1/f<0.82; wherein f is the imaging lens fG1 is an effective focal length of the first lens group, fG2 is an effective focal length of the second lens group, fG3 is an effective focal length of the third lens group, TTL is a distance from an object side surface of the lens closest to the object side to an imaging plane on the optical axis, BFL is a distance from an image side surface of the lens closest to the image side to the imaging plane on the optical axis, T11ST is a distance from the object side surface of the lens closest to the object side to an aperture on the optical axis, TSTIMA is a distance from the aperture to the imaging plane on the optical axis, and β2 is a lateral magnification of the second lens group when an object is located at infinite distance.

Images