CN116348798A

CN116348798A - Imaging lens including internal dimming device

Info

Publication number: CN116348798A
Application number: CN202080106710.6A
Authority: CN
Inventors: 宮谷崇太; 泉亮太郎; 佟庆; 安泽卓也
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2020-11-18
Filing date: 2020-11-18
Publication date: 2023-06-27
Also published as: WO2022104603A1

Abstract

An imaging lens for forming a rendered image of an object on a solid-state imaging device is disclosed. The imaging lens includes a plurality of lenses (L1, L2, L3, L4, L5, L6, L7). The plurality of lenses (L1, L2, L3, L4, L5, L6, L7) are divided from the object side to the image side into a front group (L1, L2) and a rear group (L3, L4, L5, L6, L7). The dimming means (D) are arranged at the gap between the front group (L1, L2) and the rear group (L3, L4, L5, L6, L7). An image capturing apparatus is also disclosed, which includes the imaging lens and the solid-state imaging device to convert a rendered image of an object passing through the imaging lens into an electrical signal.

Description

Imaging lens including internal dimming device

Technical Field

The present invention relates to an imaging lens, and more particularly, to an imaging lens including an internal dimming device.

The imaging lens provided by the invention forms a rendered image of an object on solid-state imaging devices such as a CCD, a COMS sensor and the like. The present invention particularly relates to an imaging lens mounted in a portable device such as a smart phone, a game machine, a personal computer, an IP camera, a home appliance, an automobile, and an unmanned aerial vehicle, and to an image capturing apparatus using the imaging lens.

Background

With the popularization of smart phones in recent years, the demands for imaging lenses are becoming diversified. Since the module thickness of an imaging lens is directly related to the size of a product in which the imaging lens is mounted, it is particularly desirable to promote the specification of the imaging lens while maintaining a small module thickness thereof. In particular, this includes a wider angle, scalability, a larger aperture, and better imaging lens optical performance, etc.

In recent years, a multi-camera system has become mainstream, and a wide-angle lens often used for photographing still images and moving images has also become a major selling point of products. Therefore, the specifications of the imaging lens also need to be upgraded. Herein, wide angle refers to a half field angle of about 40 degrees or more.

Japanese patent No. 6440173 discloses, as a wide-angle optical system generally used for capturing still images and moving images, an optical system including a total of six lenses including a first (L1) negative lens and a second (L2) positive lens.

However, since the imaging lens described in japanese patent No. 6440173 has an F value (Fno) of at least 2.2 and is dark, a sufficient amount of light cannot be ensured for capturing a moving image. Further, when the F value is increased, it is difficult to correct the aberration of the lens, and it is also difficult to obtain good optical performance of the lens. In addition, with recent increases in sensor size, many over-exposed scenes due to factors such as an increase in sensor pixels, binning processing, and the like may occur.

Therefore, there is a need for an imaging lens small enough to have a large F value while providing a light control function capable of solving the above-described technical problems in the related art.

Disclosure of Invention

According to a first aspect, an embodiment of the present invention provides an imaging lens for forming a rendered image of an object on a solid-state imaging device, the imaging lens including: a plurality of lenses are provided for the optical system,

wherein the plurality of lenses are divided from the object side to the image side into a front group and a rear group; and a dimming device is arranged at a gap between the front group and the rear group.

With reference to the first aspect, in one possible implementation manner, the front group includes two lenses, and the two lenses include, from the object side to the image side, a first lens having a negative refractive index and a second lens having a positive refractive index; the rear group includes four or more lenses including a third lens, a fourth lens, a fifth lens, a sixth lens, and optionally an nth lens (where n is a natural number equal to or greater than 7).

With reference to the first aspect, in one possible implementation manner, the gap is defined between an image side surface of the second lens (L2S 2) and an object side surface of the third lens (L3S 1); the light adjusting device is arranged in the gap.

With reference to the first aspect, in a possible implementation manner, the dimming device is free of medium on an optical axis of the imaging lens, and performs mechanical dimming through an aperture stop.

With reference to the first aspect, in a possible implementation manner, the dimming device has a medium on an optical axis of the imaging lens, and performs dimming through electrowetting or electrochromic technology.

With reference to the first aspect, in one possible implementation manner, the following conditional expression (5) is satisfied:

6％ < Dspace/TTL < 17％ (5)

wherein,,

dspace: a distance between a plane on L2S2 closest to the image side and a plane on L3S1 closest to the object side, wherein the planes are both perpendicular to the optical axis of the imaging lens;

TTL: a distance from a center of an object side surface of the first lens (L1S 1) to an image surface along the optical axis of the imaging lens.

With reference to the first aspect, in one possible implementation manner, the following conditional expressions (1) and (4) are also satisfied:

ω≧40°(1)

0.86 < ff/f < 2.8 (4)

wherein,,

omega: the half-field angle is used to determine,

f: the focal length of the entire imaging lens,

ff: focal length of the front group lens.

With reference to the first aspect, in one possible implementation manner, the following conditional expressions (2), (3) and (6) are also satisfied:

–20 < f1/f < –3 (2)

0.6 < f2/f < 1.5 (3)

–0.15 < L2S2sag < 0.15 (6)

wherein,,

f1: the focal length of the first lens is chosen to be,

f2: the focal length of the second lens is chosen to be,

L2S2sag: the sagittal height of L2S2 (the direction of progression from the lens center toward the image side is defined as positive, and the direction of progression from the lens center toward the object side is defined as negative).

With reference to the first aspect, in one possible implementation manner, the following conditional expressions (7) and (8) are also satisfied:

L2Nd > 1.50 (7)

L2vd < 57.5 (8)

wherein,,

l2Nd: the refractive index of the material of the second lens to the d-line,

l2vd: abbe number of the material of the second lens to d-line.

According to a second aspect, an embodiment of the present invention provides an image capturing apparatus including an imaging lens and a solid-state imaging device to convert a rendered image of an object passing through the imaging lens into an electrical signal:

wherein the imaging lens includes a plurality of lenses divided from an object side to an image side into a front group and a rear group; and a dimming device is arranged at a gap between the front group and the rear group.

With reference to the second aspect, in one possible implementation manner, the front group includes two lenses, and the two lenses include, from the object side to the image side, a first lens having a negative refractive index and a second lens having a positive refractive index; the rear group includes four or more lenses including a third lens, a fourth lens, a fifth lens, a sixth lens, and optionally an nth lens (where n is a natural number equal to or greater than 7).

With reference to the second aspect, in one possible implementation manner, the gap is defined between an image side surface of the second lens (L2S 2) and an object side surface of the third lens (L3S 1); the light adjusting device is arranged in the gap.

With reference to the second aspect, in a possible implementation manner, the dimming device is free of medium on an optical axis of the imaging lens, and performs mechanical dimming through an aperture stop.

With reference to the second aspect, in a possible implementation manner, the dimming device has a medium on an optical axis of the imaging lens, and performs dimming through electrowetting or electrochromic technology.

With reference to the second aspect, in one possible implementation manner, the following conditional expression (5) is satisfied:

6％ < Dspace/TTL < 17％ (5)

wherein,,

With reference to the second aspect, in one possible implementation manner, the following conditional expressions (1) and (4) are also satisfied:

ω≧40°(1)

0.86 < ff/f < 2.8 (4)

wherein,,

omega: the half-field angle is used to determine,

f: the focal length of the entire imaging lens,

ff: focal length of the front group lens.

With reference to the second aspect, in one possible implementation manner, the following conditional expressions (2), (3) and (6) are also satisfied:

–20 < f1/f < –3 (2)

0.6 < f2/f < 1.5 (3)

–0.15 < L2S2sag < 0.15 (6)

wherein,,

f1: the focal length of the first lens is chosen to be,

f2: the focal length of the second lens is chosen to be,

With reference to the second aspect, in one possible implementation manner, the following conditional expressions (7) and (8) are also satisfied:

L2Nd > 1.50 (7)

L2vd < 57.5 (8)

wherein,,

l2Nd: the refractive index of the material of the second lens to the d-line,

l2vd: abbe number of the material of the second lens to d-line.

Drawings

In order to more clearly describe the embodiments of the present invention, the drawings will be briefly described as needed. It is evident that in the following description, the drawings show only some embodiments of the invention, and that even further drawings derived from these drawings can be drawn by a person skilled in the art without the inventive effort.

Fig. 1 is a schematic diagram of an imaging lens according to an embodiment of the present invention.

Fig. 2 is a diagram of parameters of a lens in an imaging lens provided by the present invention.

Fig. 3 is a graph of spherical aberration, astigmatism, and distortion of an imaging lens according to an embodiment of the present invention.

Fig. 4 is a schematic view of an imaging lens according to another embodiment of the present invention.

Fig. 5 is a graph showing spherical aberration, astigmatism and distortion of an imaging lens according to another embodiment of the present invention.

Fig. 6 is a schematic view of an imaging lens according to still another embodiment of the present invention.

Fig. 7 is a graph of spherical aberration, astigmatism, and distortion of an imaging lens according to still another embodiment of the present invention.

Detailed Description

The imaging lens provided by the invention is composed of a front group and a rear group in order from an object side to an image side, the front group including a first lens having a negative refractive index and a second lens having a positive refractive index, the rear group including a plurality of lenses composed of four lenses, five lenses or more. Further, a dimming means is provided at a gap between the front group and the rear group, so that the light quantity, the color tone, and the like can be changed.

Accordingly, the imaging lens provided by the present invention can provide a space for inserting the dimming device by dividing the optical system into the front group and the rear group. The imaging lens provided by the invention can obtain the dimming function of incident light by using the dimming device, and the technical problem can be solved by using the image capturing device (camera system, etc.) of the imaging lens.

Further, at the time of division, by appropriately setting the refractive power of the front group composed of the first lens and the second lens, it is possible to secure a sufficient space for inserting the dimming device while maintaining high optical performance of the imaging lens, and it is possible to provide a lens having a large F value.

The refractive power of the entire imaging lens system depends largely on the lens configuration of the front group. The front group may be composed of a first lens and a second lens, the first lens having a negative refractive power and the second lens having a positive refractive power being combined to ensure a wide angle required when capturing a moving image. Herein, refractive power refers to refractive power in the paraxial (near the optical axis).

In contrast, the lenses of the rear group mainly compensate the image plane of the object, the refractive power of which is not very large. With this compensation effect, appropriate spherical aberration, astigmatism, and distortion of the imaging lens can be obtained.

In addition, the dimming means interposed at the gap between the front group and the rear group specially dim the incident light, color adjust, blur adjust, and the like.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Fig. 1 is a schematic diagram of an imaging lens according to an embodiment of the present invention. In the imaging lens provided in the present embodiment, a total of seven lenses are arranged on the optical axis. The front group in the imaging lens is a combination of the first lens (L1) and the second lens (L2), and the rear group is a combination of lenses of the third lens (L3) to the seventh lens (L7). Furthermore, a dimmer device (D) is inserted in the gap between the front and rear groups. In the drawing, a subject is placed on the left side of a first lens, and light incident on the first lens passes through all lenses including a last lens (seventh lens (L7) herein) and then reaches an image surface (IMG) placed on the right side of the last lens in the drawing through a filter (IR).

Fig. 2 shows parameters of lenses constituting the imaging lens of the present invention. Herein, a lens surface on the image side of the second lens is L2S2, and a lens surface on the object side of the third lens is L3S1. That is, in this specification, for each lens, the lens surface on the object side is S1, and the lens surface on the image side is S2. For example, a lens surface on the object side of the first lens is L1S1, and a lens surface on the image side of the first lens is L1S2. Further, the size of the cross-sectional view of each lens shown in the height direction represents the optical effective diameter of each lens.

The dimming means (D) is inserted into a space shown as "Dspace" in fig. 2, i.e., a gap between the second lens of the front group and the third lens of the rear group. Dspace is the distance between the plane on L2S2 closest to the image side and the plane on L3S1 closest to the object side, where the planes are all perpendicular to the optical axis of the imaging lens. In other words, dspace is the distance between a plane on L2S2 closest to the L3S1 side within the optically effective diameter of L2S2 that is perpendicular to the optical axis of the imaging lens and a plane on L3S1 closest to the L2S2 side within the optically effective diameter of L3S1 that is perpendicular to the optical axis of the imaging lens. In the embodiment of the invention, the specific gap value of Dspace is about 1mm.

Fig. 3, 5, and 7 are spherical aberration diagrams, astigmatism diagrams, and distortion diagrams of the imaging lens. Herein, the spherical aberration diagram shows the aberration amounts of wavelengths of the F-line (486.1 nm), d-line (587.6 nm), and C-line (656.3 nm) with solid lines. The astigmatism diagrams show the amount of aberration of d-line in the sagittal image plane S with solid lines and the amount of aberration of d-line in the tangential image plane T with broken lines. Herein, F represents an F value, and IH represents an image height. The distortion map shows aberration of d-line with solid line.

The imaging lens in each embodiment was evaluated based on the following eight parameters.

(1) ω, (2) f1/f, (3) f2/f, (4) ff/f, (5) Dspace/TTL, (6) L2S2sag, (7) L2Nd, and (8) L2vd.

Each variable is as follows.

Omega: angle of half field

f1: focal length of the first lens (L1)

f2: focal length of the second lens (L2)

f: focal length of the entire imaging lens system

ff: focal length of front group lens

Dspace: distance between front and rear group (as described above)

TTL: distance from center of object side surface of first lens (L1S 1) to image surface

L2S2sag: the sagittal height of L2S2 (the direction of progression from the lens center toward the image side is defined as positive, and the direction of progression from the lens center toward the object side is defined as negative)

L2Nd: refractive index of the second lens (L2) material to d-line

L2vd: abbe number of the second lens (L2) material to d-line

The schematic diagram of the imaging lens shown in fig. 1 shows a first embodiment (embodiment 1) of the present invention. Embodiment 1 includes, in order from the object side to the image side, a front group composed of an L1 lens having a negative refractive index and an L2 lens having a positive refractive index, and a rear group composed of an L3 lens having a negative refractive index, an L4 lens having a negative refractive index, an L5 lens having a positive refractive index, an L6 lens having a negative refractive index, and an L7 lens having a negative refractive index. The dimming device D is inserted at a gap between the front group and the rear group, and is capable of changing the light quantity and the color tone. Here, the dimmer D has no medium on the optical axis, but it can dim by a mechanical device such as an iris blade or an ND filter. Further, a filter IR such as an infrared filter or a cover glass is provided between the L7 lens and the image surface IMG. The filter IR may be omitted.

Fig. 3 is a graph of spherical aberration, astigmatism, and distortion of the imaging lens of embodiment 1. They demonstrate that the imaging lens has sufficient desired optical performance.

The schematic diagram of the imaging lens shown in fig. 4 shows a second embodiment (embodiment 2) of the present invention. Embodiment 2 includes, in order from the object side to the image side, a front group composed of an L1 lens having a negative refractive index and an L2 lens having a positive refractive index, and a rear group composed of an L3 lens having a negative refractive index, an L4 lens having a positive refractive index, an L5 lens having a negative refractive index, and an L6 lens having a negative refractive index. The dimming device D is inserted at a gap between the front group and the rear group, and is capable of changing the light quantity and the color tone. Here, the dimming device D has a medium on the optical axis, and it can dim or change color using, for example, the principle of electrowetting or electrochromic, or the like. Further, a filter IR such as an infrared filter or a cover glass is provided between the L6 lens and the image surface IMG. The filter IR may be omitted.

Fig. 5 is a graph of spherical aberration, astigmatism, and distortion of the imaging lens of embodiment 2. They demonstrate that the imaging lens has sufficient desired optical performance.

The schematic diagram of the imaging lens shown in fig. 6 shows a third embodiment (embodiment 3) of the present invention. Embodiment 3 includes, in order from the object side to the image side, a front group composed of an L1 lens having a negative refractive index and an L2 lens having a positive refractive index, and a rear group composed of an L3 lens having a positive refractive index, an L4 lens having a positive refractive index, an L5 lens having a positive refractive index, and an L6 lens having a positive refractive index. The dimming device D is inserted at a gap between the front group and the rear group, and is capable of changing the light quantity and the color tone. Here, the dimming device D has a medium on the optical axis, and it can dim or change color using, for example, the principle of electrowetting or electrochromic, or the like. Further, a filter IR such as an infrared filter or a cover glass is provided between the L6 lens and the image surface IMG. The filter IR may be omitted.

Fig. 7 is a graph of spherical aberration, astigmatism, and distortion of the imaging lens of embodiment 3. They demonstrate that the imaging lens has sufficient desired optical performance.

The imaging lens in these embodiments can obtain desired optical performance by satisfying the following conditional expressions from (1) to (8).

Conditional expression (1): omega ∈40°

Conditional expression (2): -20< f1/f < -3

Conditional expression (3): 0.6< f2/f <1.5

Conditional expression (4): 0.86< ff/f <2.8

Conditional expression (5): 6% < Dspace/TTL <17%

Conditional expression (6): -0.15< L2S2sag <0.15

Conditional expression (7): l2Nd >1.50

Conditional expression (8): l2vd <57.5

The imaging lens in the present embodiment first needs to satisfy conditional expression (5). Conditional expression (5) is a range in which an appropriate space for inserting the dimming device can be provided while ensuring the optical performance required within the optical system. Below this range, it becomes physically difficult to provide the dimming means within the optical system, and thus it may be necessary to install the dimming means outside the optical system. As a result, the overall size of the camera device increases. Further, when this range is exceeded, a large air gap is generated in the optical system, making it difficult to perform efficient aberration correction. As a result, the size of the optical system itself increases, and the optical performance decreases (i.e., the correction of astigmatism and image plane curvature is insufficient).

The imaging lens in the present embodiment is expected to also satisfy conditional expressions (1) and (4). Conditional expressions (1) and (4) are appropriate ranges for ensuring good optical performance in a lens configuration divided into front and rear groups while maintaining a wide angle of view of the imaging lens. Conditional expression (1) is a half field angle required for a wide-angle lens. If the ratio of the focal length of the front group to the focal length of the entire lens system (as shown in conditional expression (4)) exceeds this range, the correction effect of spherical aberration is weakened, and it is difficult to provide a bright lens corresponding to the capturing of a moving image. Further, when the angle is below this range, it is difficult to maintain a wide field angle, and at the same time, good correction of the curvature and distortion of the image plane cannot be performed.

The imaging lens in the present embodiment is expected to also satisfy conditional expressions (2), (3), and (6). Conditional expression (2) shows a range that effectively provides good correction of astigmatism and image plane curvature while maintaining a wide field angle. By satisfying the range of conditional expression (2), the negative refractive power of the first lens is suppressed from being impaired, and the light can be incident into the second lens at an appropriate angle of the light emitted from the first lens. Thus, a wide angle can be more easily achieved. Further, it is possible to prevent the balance of the refractive power of the first lens with respect to the focal length of the entire lens system from becoming too strong, thereby ensuring proper correction of the image plane curvature and distortion. Further, conditional expression (3) shows a range in which shortening of the total optical length of the imaging lens is effectively achieved while good aberration correction is achieved. By satisfying the range of conditional expression (3), the positive refractive power increase of the second lens can be suppressed, and therefore, appropriate correction effects of spherical aberration and frame aberration can be provided. Further, conditional expression (6) shows a range in which an appropriate lens shape is provided to facilitate the manufacture thereof while maintaining good aberration correction.

The imaging lens in the present embodiment is expected to also satisfy conditional expressions (7) and (8). Conditional expressions (7) and (8) show the material of L2 to provide a range of the best bright lens to take a moving image. By satisfying these ranges, various aberrations can be well corrected in spite of a large F value, and in particular, excellent correction effects of spherical aberration and frame aberration can be obtained.

Tables 1 and 2 show lens data in embodiment 1 of the present invention, where i is the number of surfaces counted from the object side to the image side, r is the radius of curvature, d is the distance between the upper surfaces of the optical axes (thickness of the lens center or air gap), nd is the refractive index of d-line, vd is the abbe number of d-line, and STO represents the aperture. Furthermore, the aspherical surface is represented by adding an sign of an x (asterisk) after the number of surfaces i. Further, the aspherical shape adopted on the aspherical surface of the lens surface is defined by the following equation 1, where z is the distance (sagittal height) from the lens surface vertex in the optical axis direction, H is the height in the direction perpendicular to the optical axis direction, c is the paraxial curvature (reciprocal of curvature radius) at the lens vertex, k is the conic constant (conic constant), and A4, A6, A8, a10, a12, a14, a16, a18, and a20 are the aspherical coefficients of the fourth, sixth, eighth, tenth, twelfth, fourteenth, sixteenth, eighteenth, and twentieth orders, respectively.

[ equation 1]

TABLE 1

TABLE 2

ASP

K

A4

A6

A8

A10

A12

A14

A16

A18

A20

1

–8.96114E+ 01

–2.92497E– 02

–1.30704E– 02

1.09270E– 02

–2.86874E– 03

1.10325E– 04

1.03605E– 04

–2.40000E– 05

2.00000E– 06

–6.85035E–08

2

–5.48999E+ 01

1.45543E– 02

–6.05910E– 02

4.83939E– 02

–2.09959E– 02

5.55062E– 03

–9.12997E– 04

9.10000E– 05

–5.00000E– 06

1.19318E–07

3

–2.00239E+ 00

2.78477E– 02

–2.61826E– 02

1.94557E– 02

–8.26299E– 03

2.10765E– 03

–3.30432E– 04

3.10000E– 05

–2.00000E– 06

3.61020E–08

4

–7.29361E+ 00

–2.25431E– 03

2.96543E– 03

–2.55412E– 03

1.66772E– 03

–6.63128E– 04

1.49269E– 04

–1.90000E– 05

1.00000E– 06

–3.25048E–08

6

–9.00000E+ 01

–3.13022E– 02

–1.79068E– 02

1.87293E– 02

–1.35516E– 02

6.90897E– 03

–2.04265E– 03

3.34420E– 04

–2.80000E– 05

1.00000E–06

7

–8.54675E+ 01

–1.25649E– 02

–3.25713E– 02

2.97271E– 02

–2.12794E– 02

1.04352E– 02

–3.05090E– 03

5.09008E– 04

–4.50000E– 05

2.00000E–06

8

–7.71256E+ 01

–3.50631E– 02

–8.97152E– 03

8.90745E– 03

–7.49760E– 03

3.61175E– 03

–9.45915E– 04

1.38733E– 04

–1.10000E– 05

3.51844E–07

9

8.93551E+ 01

–4.01835E– 02

2.78230E– 03

–5.20000E– 05

4.86840E– 07

–2.70025E– 09

9.27157E– 12

–2.31970E– 14

5.29893E– 16

–2.38267E–17

10

8.43326E+ 00

3.96626E– 03

–5.92227E– 03

1.42955E– 03

–1.81767E– 04

1.30000E– 05

–1.00000E– 06

1.50883E– 08

–2.11545E– 10

1.24594E–12

11

–6.66774E+ 00

–4.02316E– 02

8.04447E– 03

–5.12412E– 04

–6.72491E– 04

2.55201E– 04

–3.80000E– 05

3.00000E– 06

–1.00841E– 07

1.44117E–09

12

–5.29941E+ 00

–1.87861E– 02

4.33924E– 03

–1.58103E– 03

3.07341E– 04

–3.70000E– 05

3.00000E– 06

–1.17252E– 07

2.68589E– 09

–2.53002E–11

13

–8.31826E+ 00

–1.20855E– 03

–2.37320E– 03

3.68342E– 04

–3.40000E– 05

2.00000E– 06

–7.78734E– 08

1.71977E– 09

–2.02802E– 11

9.86041E–14

14

–6.61766E– 01

–8.22097E– 02

1.27263E– 02

–1.19707E– 03

8.10000E– 05

–4.00000E– 06

1.33468E– 07

–2.78781E– 09

3.23299E– 11

–1.58081E–13

15

–5.13369E+ 00

–2.94491E– 02

4.65130E– 03

–5.62651E– 04

4.70000E– 05

–3.00000E– 06

8.94092E– 08

–1.78906E– 09

1.88883E– 11

–8.07952E–14

Tables 3 and 4 are lens data in example 2 of the present invention.

TABLE 3 Table 3

i	r	d	Nd	vd
					Object surface	Infinity is provided	Infinity is provided
1*	3.13964	0.25859	1.671	19.224
					2*	2.38023	0.06567
3*	3.16897	0.70109	1.768	49.219
					4*	33.76007	0.14374
5(STO)	Infinity is provided	0.54000	1.474	62.168
					6	Infinity is provided	0.42916
7*	53.42310	0.41792	1.671	19.224
					8*	18.41355	0.37720
9*	–3.92733	0.99939	1.545	56.019
					10*	–1.62763	0.04147
11*	3.08312	0.44426	1.671	19.224
					12*	1.92871	0.90138
13*	4.20060	0.71457	1.531	55.726
					14*	2.10354	0.65557
15	Infinity is provided	0.21000	1.517	64.175
					16	Infinity is provided	0.30000
IMG	Infinity is provided	0.00000

TABLE 4 Table 4

Tables 5 and 6 are lens data in example 3 of the present invention.

TABLE 5

i	r	d	Nd	vd
					Object surface	Infinity is provided	Infinity is provided
1*	3.58516	0.20654	1.671	19.226
					2*	3.06358	0.14753
3*	2.90538	0.75955	1.545	56.019
					4*	–16.85938	0.09367
5(STO)	Infinity is provided	0.53000	1.474	62.143
					6	Infinity is provided	0.62689
7*	–10.37256	0.46465	1.671	19.226
					8*	18.13255	0.11765
9*	–4.64184	0.67320	1.545	56.019
					10*	–2.14065	0.04000
11*	4.32584	0.76099	1.636	23.907
					12*	3.60504	1.19121
13*	17.20510	0.70636	1.531	55.726
					14*	2.81468	0.34558
15	Infinity is provided	0.21000	1.517	64.174
					16	Infinity is provided	0.30000
IMG	Infinity is provided	0.00000

TABLE 6

ASP

K

A4

A6

A8

A10

A12

A14

A16

A18

A20

1

–4.61236E+ 00

– 1.77986E– 02

–2.72552E– 02

1.30869E– 02

–2.53395E– 03

2.33507E–04

–9.00000E– 06

–1.45556E– 07

1.95920E– 08

–4.04957E–10

2

–3.30779E+ 00

– 4.93784E– 03

–5.44651E– 02

3.30205E– 02

–9.55153E– 03

1.63436E–03

–1.68924E– 04

1.00000E– 05

–3.35426E– 07

4.55395E–09

3

1.83569E+ 00

6.80761E– 03

–2.80821E– 02

1.51872E– 02

–4.98231E– 03

8.66293E–04

–8.40000E– 05

5.00000E– 06

–1.33730E– 07

1.60697E–09

4

9.00000E+ 01

2.04013E– 04

–8.59093E– 03

1.93621E– 02

–1.92837E– 02

9.77634E–03

–2.50894E– 03

3.36446E– 04

–2.30000E– 05

1.00000E–06

7

3.42366E+ 01

– 7.31921E– 02

1.47725E– 02

– 8.27719E– 03

5.94454E– 03

–1.35831E– 03

1.45857E–04

–8.00000E– 06

2.36664E– 07

–2.74688E–09

8

8.75402E+ 01

– 8.30401E– 02

1.99642E– 02

– 8.15974E– 03

3.57030E– 03

–6.29326E– 04

5.50000E–05

–3.00000E– 06

6.53676E– 08

–6.62594E–10

9

3.88830E+ 00

1.66031E– 02

6.97756E– 03

– 4.44893E– 03

7.62145E– 04

–6.00000E– 05

3.00000E–06

–6.31074E– 08

8.10447E– 10

–4.30015E–12

10

–8.56095E+ 00

– 4.46206E– 02

3.54886E– 02

– 1.28377E– 02

1.98075E– 03

–1.53350E– 04

7.00000E–06

–1.60096E– 07

2.06845E– 09

–1.10529E–11

11

1.84835E+ 00

– 1.53475E– 02

–3.78174E– 03

2.37147E– 04

–1.90000E– 05

–1.20000E– 05

2.00000E–06

–7.91041E– 08

1.71277E– 09

–1.40412E–11

12

–2.23940E+ 01

9.06182E– 03

–5.14606E– 03

7.14319E– 04

–5.80000E– 05

3.00000E–06

–8.52292E– 08

1.42832E– 09

–1.25872E– 11

4.53473E–14

13

1.88482E+ 01

– 6.35445E– 02

8.31824E– 03

– 4.77833E– 04

1.40000E– 05

–2.13864E– 07

1.97062E–09

–1.05836E– 11

3.07143E– 14

–3.72414E–17

14

–9.81052E+ 00

– 1.51808E– 02

1.08867E– 03

– 8.40000E– 05

3.00000E– 06

–7.02378E– 08

7.38250E–10

–4.18741E– 12

1.21639E– 14

–1.42040E–17

Table 7 shows the parameters of examples 1 to 3 of the present invention.

TABLE 7

	Example 1	Example 2	Example 3
				F(mm)	5.13	4.91	5.35
Fno	1.49	1.58	1.84
				Ω(°)	46.07	45.78	44.93
IH(mm)	5.20	5.20	5.20
				TTL(mm)	7.20	7.20	7.17
f1(mm)	–25.68	–16.98	–37.30
				f2(mm)	4.84	4.51	4.61
Ff(mm)	6.01	9.45	7.92
				(1)ω	46.07	45.78	44.93
(2)f1/f	–5.00	–3.46	–6.97
				(3)f2/f	0.94	0.92	0.86
(4)ff/f	1.17	1.93	1.48
				(5)Dspace/TTL	9％	8.47％	11.16％
(6)L2S2sag	–0.10	0.06	–0.07
				(7)L2Nd	1.768	1.768	1.545

Fno is the F value, IH is the maximum image height, F1 is the focal length of the L1 lens, and F2 is the focal length of the L2 lens.

It is to be understood that the imaging lens provided in embodiment 1 of the present invention satisfies conditional expressions (1) to (8) shown in table 7.

It is also understood that the imaging lens provided in embodiment 2 of the present invention satisfies conditional expressions (1) to (8) shown in table 7.

It is also understood that the imaging lens provided in embodiment 3 of the present invention satisfies conditional expressions (1) to (8) shown in table 7.

The invention can provide a compact and bright imaging lens with high optical performance, and the imaging lens can adjust light or color or has the two functions. When dimmed, a user experience of a wide dynamic range, etc., can be provided, which can obtain an appropriate exposure under any shooting condition of the camera system and provide a long-second exposure with artistic effects. In the color mixing, a photographing effect obtained by the color filter can be provided.

The above description illustrates embodiments provided by the present application, but is not intended to limit the invention. Any modifications, equivalent substitutions or improvements made without departing from the spirit and principles of the present invention are intended to be included within the scope of the present application.

Symbol description

L1: first lens

L2: second lens

L1S1: object side surface of first lens

L1S2: image side surface of first lens

IR: filter lens

Claims

1. An imaging lens for forming a rendered image of an object on a solid-state imaging device, the imaging lens comprising:

a plurality of lenses are provided for the optical system,

wherein the plurality of lenses are divided from the object side to the image side into a front group and a rear group;

and a dimming device is arranged at the gap between the front group and the rear group.

2. The imaging lens as claimed in claim 1, wherein,

the front group includes two lenses including a first lens having a negative refractive index and a second lens having a positive refractive index from the object side to the image side;

the rear group includes four or more lenses including a third lens, a fourth lens, a fifth lens, a sixth lens, and optionally an nth lens (where n is a natural number equal to or greater than 7).

3. The imaging lens according to claim 2, wherein the gap is defined between an image side surface of the second lens (L2S 2) and an object side surface of the third lens (L3S 1);

wherein, be provided with in the clearance the dimming device.

4. An imaging lens as claimed in any one of claims 1 to 3, wherein the dimming means is devoid of medium on the optical axis of the imaging lens and mechanically dimmed by an aperture stop.

5. An imaging lens as claimed in any one of claims 1 to 3, wherein the dimming means has a medium on the optical axis of the imaging lens and dimming is performed by electrowetting or electrochromic technology.

6. The imaging lens according to any one of claims 1 to 5, characterized in that the following conditional expression (5) is satisfied:

6％ < Dspace/TTL < 17％ (5)

wherein,,

7. The imaging lens according to claim 6, wherein the following conditional expressions (1) and (4) are also satisfied:

ω≧40°(1)

0.86 < ff/f < 2.8 (4)

wherein,,

omega: the half-field angle is used to determine,

f: the focal length of the entire imaging lens,

ff: focal length of the front group lens.

8. The imaging lens according to claim 7, wherein the following conditional expressions (2), (3) and (6) are also satisfied:

–20 < f1/f < –3 (2)

0.6 < f2/f < 1.5 (3)

–0.15 < L2S2sag < 0.15 (6)

wherein,,

f1: the focal length of the first lens is chosen to be,

f2: the focal length of the second lens is chosen to be,

9. The imaging lens according to claim 8, wherein the following conditional expressions (7) and (8) are also satisfied:

L2Nd > 1.50 (7)

L2vd < 57.5 (8)

wherein,,

l2Nd: the refractive index of the material of the second lens to the d-line,

l2vd: abbe number of the material of the second lens to d-line.

10. An image capturing apparatus characterized by comprising an imaging lens and a solid-state imaging device to convert a rendered image of an object passing through the imaging lens into an electric signal:

wherein the imaging lens comprises a plurality of lenses;

11. The image capturing device of claim 10, wherein,

12. The image capturing device according to claim 11, wherein the gap is defined between an image side surface of the second lens (L2S 2) and an object side surface of the third lens (L3S 1);

wherein, be provided with in the clearance the dimming device.

13. The image capturing apparatus according to any one of claims 10 to 12, wherein the dimming means is free of a medium on an optical axis of the imaging lens and mechanically dimmed by an aperture stop.

14. The image capturing apparatus according to any one of claims 10 to 12, wherein the dimming means has a medium on an optical axis of the imaging lens, and dimming is performed by an electrowetting or electrochromic technique.

15. The image capturing apparatus according to any one of claims 10 to 14, wherein the following conditional expression (5) is satisfied:

6％ < Dspace/TTL < 17％ (5)

wherein,,

16. The image capturing apparatus according to claim 15, wherein the following conditional expressions (1) and (4) are also satisfied:

ω≧40°(1)

0.86 < ff/f < 2.8 (4)

wherein,,

omega: the half-field angle is used to determine,

f: the focal length of the entire imaging lens,

ff: focal length of the front group lens.

17. The image capturing apparatus according to claim 16, wherein the following conditional expressions (2), (3) and (6) are also satisfied:

–20 < f1/f < –3 (2)

0.6 < f2/f < 1.5 (3)

–0.15 < L2S2sag < 0.15 (6)

wherein,,

f1: the focal length of the first lens is chosen to be,

f2: the focal length of the second lens is chosen to be,

18. The imaging lens according to claim 17, wherein the following conditional expressions (7) and (8) are also satisfied:

L2Nd > 1.50 (7)

L2vd < 57.5 (8)

wherein,,

l2Nd: the refractive index of the material of the second lens to the d-line,

l2vd: abbe number of the material of the second lens to d-line.