CN110161666B

CN110161666B - High-magnification macro lens

Info

Publication number: CN110161666B
Application number: CN201910419340.0A
Authority: CN
Inventors: 李大勇
Original assignee: Anhui Changgeng Optics Technology Co ltd
Current assignee: Anhui Changgeng Optics Technology Co ltd
Priority date: 2019-05-20
Filing date: 2019-05-20
Publication date: 2024-03-26
Anticipated expiration: 2039-05-20
Also published as: CN110161666A

Abstract

The invention belongs to the technical field of optical devices, and particularly relates to a high-magnification micro-lens, which sequentially comprises a first lens group, a second lens group with positive diopter, a diaphragm and a third lens group with negative diopter from an object side to an image side; the second lens group consists of two continuous positive diopter lenses and a plurality of lenses from the object side; when an object moves from infinity to a close distance, the first lens group and the third lens group are fixed, and the second lens group moves from the image surface side to the object side to realize focusing; the invention provides a miniature lens with high performance, which can well image from infinity to more than 1.5 times of photographic multiplying power and realizes miniaturization, low cost.

Description

High-magnification macro lens

Technical Field

The invention belongs to the technical field of optical devices, and particularly relates to a high-magnification macro lens.

Background

Currently, the interchangeable lenses used in cameras are various in macro lenses ranging from infinity to a magnification of magnification, for example, japanese patent application laid-open No. 2006-153942 and japanese patent application laid-open No. 2012-53260, and each lens group has a structure in which diopters are sequentially positive, negative, positive and negative, and in which an object is focused by moving the 2 nd and 3 rd lens groups and the 1 st and 4 th lens groups are fixed in a focusing process ranging from infinity to a magnification of magnification. Although a good imaging effect can be obtained, the number of lenses is large, and the movement of the 2 nd group and the 3 rd group can offset and interfere with each other, so that the micro-distance effect with higher magnification is not easy to realize, the miniaturization is not easy to realize in volume, and the realization of low cost is difficult.

For another example, japanese patent application laid-open No. 2012-63403, the diopters of each lens group are positive, negative, and positive in order from the object side, and in the process that the object is from infinity to the photographing magnification being equal, the 2 nd group and the 3 rd group lens groups move to focus, and the 1 st group and the 4,5,6 th groups are fixed, so that although a good imaging effect can be obtained, the number of lenses is large, and low cost and miniaturization cannot be realized; meanwhile, the group 2 and the group 3 share a moving space, so that the moving quantity is limited, and the macro effect of higher multiplying power cannot be realized.

Disclosure of Invention

The invention aims to overcome the defects that the prior macro lens cannot achieve higher magnification, has huge volume and high cost, and provides the high-magnification macro lens which can achieve high-performance imaging effect from infinity to more than 1.5 times of shooting magnification, has small volume and low cost.

In order to achieve the above purpose, the invention is realized by adopting the following technical scheme:

the high-magnification macro lens comprises a first lens group, a second lens group with positive diopter, a diaphragm and a third lens group with negative diopter in sequence from an object side to an image plane side;

the second lens group consists of two continuous positive diopter lenses and a plurality of lenses from the object side; when an object moves from infinity to a close distance, the first lens group and the third lens group are fixed, and the second lens group moves from the image surface side to the object side to realize focusing;

the high-magnification macro lens also meets the following conditional expression:

0.2≤|F2/F3|≤0.9 (1)

1.2≤|FL/S2|≤2.5 (2)；

wherein,

f2: a focal distance of the second lens group;

f3: a focal distance of the third lens group;

FL: in an infinity state, the focal distance of the entire optical system;

s2: and the maximum moving amount of the second lens group when the object is at the maximum photographing multiplying power from infinity.

Preferably, the high-magnification macro lens further satisfies:

1.5≤FL/F2≤2.5 (3)

wherein,

FL: in an infinity state, the focal distance of the entire optical system;

f2: focal distance of the second lens group.

Preferably, the high-magnification macro lens further satisfies:

0.5≤L/(At×FL)≤1.2 (4)

wherein,

l: the length of the entire optical system, specifically, the value of L refers to the distance from the object side, the first surface to the image surface;

at: maximum photographing magnification;

FL: in the infinity state, the focal distance of the entire optical system.

In the present invention, if the upper limit of the conditional expression (1) is exceeded, the diopter of the second lens group is too weak, and although the aberration is easily corrected, the focusing function of high magnification macro cannot be realized in a limited space. If more than 1.5 times of photographic effect is to be realized, the volume is huge; if the lower limit of the conditional expression (1) is exceeded, although miniaturization is easy and high magnification imaging effect is easy to achieve, correction of the aberrations generated by the excessively strong diopter of the first lens group is extremely difficult and high performance cannot be achieved.

If the upper limit of the conditional expression (2) is exceeded, the amount of focus movement of the second lens group is too small, making it difficult to achieve a photographing magnification of 1.5 times or more; if the lower limit of the conditional expression (2) is exceeded, it is easy to achieve a photographing magnification of 1.5 times or more, but the lens is bulky due to an excessive amount of movement, so that the practicality is lost and the cost is also greatly increased.

If the upper limit of the conditional expression (3) is exceeded, the diopter of the second lens group is too strong, and although miniaturization of the volume and photographing magnification of 1.5 times or more are easily achieved, various aberrations are caused due to the too strong diopter, good correction is difficult, and high-performance photographing effect is not achieved; if the lower limit of the conditional expression (3) is exceeded, although the performance is easily ensured, since the diopter of the second lens group is too weak, the amount of movement is large to achieve the high magnification photographing effect, resulting in a bulky optical system, which cannot be miniaturized and is low in cost.

If the upper limit of the conditional expression (4) is exceeded, the entire optical system becomes excessively large in volume, and miniaturization cannot be achieved, or a photographing magnification of 1.5 times or more cannot be achieved; if the lower limit of the conditional expression (4) is exceeded, although miniaturization or high magnification can be achieved, various aberrations are inevitably caused and excellent correction cannot be obtained because of the too small volume, resulting in failure to achieve a high-performance photographing effect.

Compared with the prior art, the invention has the following technical effects:

the invention provides a miniature lens with high performance, which can well image from infinity to more than 1.5 times of photographic multiplying power and realizes miniaturization, low cost.

Drawings

Fig. 1 is a schematic diagram of a macro lens provided in embodiment 1;

fig. 2 shows spherical aberration, curvature of field, distortion aberration, and chromatic aberration of magnification at infinity and at an equal photographing magnification for example 1;

fig. 3 is a schematic diagram of a macro lens provided in embodiment 2;

fig. 4 shows infinity, spherical aberration of 1-fold and 2-fold photographing magnification, field curvature aberration, distortion aberration, and chromatic aberration of magnification in example 2.

Detailed Description

In order to make the technical means, the creation characteristics, the achievement of the purpose and the effect of the present invention easy to understand, the present invention is further explained below with reference to the specific drawings.

Example 1

Referring to fig. 1, a macro lens includes, in order from an object side to an image plane side, a first lens group G1, a second lens group G2 of positive refractive power, and a stop, a third lens group G3 of negative refractive power;

when an object moves from infinity to a close distance, the first lens group G1 and the third lens group G3 are fixed, and the second lens group G2 moves from the image plane side to the object side to realize focusing.

The spherical aberration, the field curvature aberration, the distortion aberration, and the chromatic aberration of magnification of infinity, equal photographing magnification of example 1 are shown in fig. 2.

The data for example 1 are as follows:

wherein,

r (mm): radius of curvature of each face;

d (mm): each lens spacing and lens thickness;

nd: refractive index of each glass of d-line;

vd: abbe number of the glass;

focal distance: 50.9586;

Fno：2.9

half angle ω:11.963

F	50.9586	1.95 times
			D(3)	29.0031	1.0000
D(16)	1.1000	29.1031
			D(27)	1.0000	1.0000

Example 2

As shown in fig. 3, a macro lens includes, in order from an object side to an image plane side, a first lens group G1, a second lens group G2 of positive diopter and a stop, a third lens group G3 of negative diopter;

the object moves from infinity to close distance, the first lens group G1 and the third lens group G3 are fixed, and the second lens group G2 moves from the image plane side to the object side to realize focusing.

The spherical aberration, the field curvature aberration, the distortion aberration, and the chromatic aberration of magnification of 1-fold photographing magnification and 2-fold photographing magnification of example 2 are shown in fig. 4.

The data for example 2 are as follows:

wherein,

r (mm): radius of curvature of each face;

d (mm): each lens spacing and lens thickness;

nd: refractive index of each glass of d-line;

vd: abbe number of the glass;

focal distance: 66.0242;

Fno：2.9

half angle ω:12.1384

F	66.0242	1.95 times
			D(3)	36.0482	1.0481
D(17)	1.3000	36.3001
			D(28)	1.0000	1.0000

The condition is satisfied:

conditional expression	Example 1	Example 2
			Conditional (1): 0.2 is less than or equal to \|f2/F3 is less than or equal to 0.9	0.590	0.333
Conditional (2): 1.2 is less than or equal to \|FL/S2 is less than or equal to 2.5	1.814	1.886
			Conditional (3): fL/F2 is 1.5-2.5	1.887	1.928
Conditional (4): L/(AtFL) is more than or equal to 0.5 and less than or equal to 1.2	0.879	0.867

The micro-lens provided by the invention can well image from infinity to more than 1.5 times of multiplying power, has the advantages of miniaturization, low cost and high multiplying power, and can be widely applied to the fields of digital camera lenses, video camera lenses, especially interchangeable camera lenses and the like.

The foregoing has outlined and described the basic principles, main features and features of the present invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, and that the above embodiments and descriptions are merely illustrative of the principles of the present invention, and various changes and modifications may be made therein without departing from the spirit and scope of the invention, which is defined by the appended claims. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims

1. A high magnification macro lens, characterized by comprising, in order from an object side to an image plane side, a first lens group (G1), a second lens group (G2) of positive diopter and a stop, a third lens group (G3) of negative diopter;

wherein, from the object side, the second lens group (G2) consists of seven lenses, wherein, the second lens group comprises two continuous positive diopter lenses; when an object moves from infinity to a close distance, the first lens group (G1) and the third lens group (G3) are fixed, and the second lens group (G2) moves from an image plane side to the object side to realize focusing;

0.2≤|F2/F3|≤0.9 （1）

1.2≤|FL/S2|≤2.5 （2）；

wherein,

f2: a focal distance of the second lens group (G2);

f3: a focal distance of the third lens group (G3);

FL: in an infinity state, the focal distance of the entire optical system;

s2: and a maximum movement amount of the second lens group (G2) when the object is at the maximum photographing magnification from infinity.

2. The high magnification macro lens of claim 1, wherein the high magnification macro lens further satisfies:

1.5≤FL/F2≤2.5 （3）

wherein,

FL: in an infinity state, the focal distance of the entire optical system;

f2: the focal distance of the second lens group (G2).

3. The high magnification macro lens of claim 1, wherein the high magnification macro lens further satisfies:

0.5≤L/(At×FL)≤1.2 （4）

wherein,

l: the length of the entire optical system;

at: maximum photographing magnification;

FL: in the infinity state, the focal distance of the entire optical system.