CN110161666A

CN110161666A - A kind of high magnification micro-lens

Info

Publication number: CN110161666A
Application number: CN201910419340.0A
Authority: CN
Inventors: 李大勇
Original assignee: ANHUI CHANGGENG OPTICAL TECHNOLOGY Co Ltd
Current assignee: ANHUI CHANGGENG OPTICAL TECHNOLOGY Co Ltd
Priority date: 2019-05-20
Filing date: 2019-05-20
Publication date: 2019-08-23
Anticipated expiration: 2039-05-20
Also published as: CN110161666B

Abstract

The invention belongs to field of optical device technology, and in particular to a kind of high magnification micro-lens successively includes the first lens group, the second lens group and diaphragm of positive diopter, the third lens group of negative diopter to image planes side from object side；Wherein, since object side, second lens group is made of continuous two panels positive diopter lens and several pieces of eyeglasses；When object is mobile to short distance from infinity, first lens group and the third lens group are fixed, and second lens group is mobile to realize focus by the lateral object side of image planes；The present invention provides one kind can be imaged from infinite as far as 1.5 times or more photography multiplying powers very well, and realize miniaturization, low cost and high performance micro-lens.

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

At present, the interchangeable lens used in a camera has a wide variety of macro lenses from infinity to an equal magnification, for example, in japanese patent laid-open nos. 2006-153942 and 2012-53260, diopters of each lens group are positive, negative, positive and negative in order from the object side, in the focusing process of an object from infinity to an equal magnification, the lens groups of the group 2 and the group 3 are moved to focus, and the group 1 and the group 4 are fixed. Although a good imaging effect can be obtained, the number of lenses is large, and the 2 nd group and the 3 rd group move to mutually offset and interfere, so that a macro effect with higher magnification is not easy to realize, miniaturization is not easy to realize in volume, and low cost is difficult to realize.

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

Disclosure of Invention

The invention aims to overcome the defects that the known macro lens cannot realize higher magnification, is large in size and high in cost, and provides the high-magnification macro lens which can realize high-performance imaging effect from infinity to more than 1.5 times of photographing magnification, and is small in size and low in cost.

In order to achieve the purpose, the invention adopts the following technical scheme:

a high-power 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 surface side;

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

the high-magnification macro lens further satisfies the following conditional expression:

0.2≤|F2/F3|≤0.9 (1)

1.2≤|FL/S2|≤2.5 (2)；

wherein,

f2: a focal length of the second lens group;

f3: a focal length of the third lens group;

FL: focal length of the entire optical system at infinity;

s2: the maximum moving amount of the second lens group when the object is from infinity to the maximum photographing magnification.

Preferably, the high-magnification macro lens further satisfies the following conditions:

1.5≤FL/F2≤2.5 (3)

wherein,

FL: focal length of the entire optical system at infinity;

f2: focal distance of the second lens group.

0.5≤L/(At×FL)≤1.2 (4)

wherein,

l: the length of the whole optical system, specifically, the value of L is the distance from the object side to the image plane from the first plane;

at: maximum photographing magnification;

FL: the focal length of the whole optical system in the infinite state.

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 the high magnification macro cannot be realized in a limited space. If the photographic effect of more than 1.5 times is realized, the volume is huge; if the refractive power exceeds the lower limit of the conditional expression (1), the reduction in size and the high-power image pickup effect can be easily achieved, but the generated aberration is very difficult to correct due to the excessively strong diopter of the first lens group, and high performance cannot be achieved.

If the upper limit of the conditional expression (2) is exceeded, the focusing movement amount of the second lens group is too small, and it is difficult to achieve a photographing magnification of 1.5 times or more; if the lower limit of the conditional expression (2) is exceeded, although it is easy to realize a photographing magnification of 1.5 times or more, the lens becomes bulky due to an excessively large amount of movement, and thus the practicability is lost, and the cost is 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 the volume miniaturization and the photographing magnification of 1.5 times or more are easily realized, since the diopter is too strong, various aberrations are caused, and the correction is difficult to be good, and the high-performance photographing effect is not realized; 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 realize a high magnification photographing effect, and the optical system is bulky, and cannot be miniaturized, and the cost is low.

If the upper limit of the conditional expression (4) is exceeded, the volume of the entire optical system is too large, and the optical system cannot be downsized, or cannot achieve a photographing magnification of 1.5 times or more; if the lower limit of the conditional expression (4) is exceeded, miniaturization and high magnification can be achieved, but since the volume is too small, various aberrations are inevitably caused and good correction cannot be obtained, and a high-performance imaging effect cannot be achieved.

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

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

Drawings

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

FIG. 2 is a diagram showing spherical aberration, field curvature aberration, distortion aberration and chromatic aberration of magnification at infinity and a constant photographing magnification in example 1;

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

FIG. 4 shows the spherical aberration, the field curvature aberration, the distortion aberration and the chromatic aberration of magnification at infinity, 1-time photographing magnification and 2-time photographing magnification of example 2.

Detailed Description

In order to make the technical means, the creation characteristics, the achievement purposes and the effects of the invention easy to understand, the invention is further clarified by combining the specific drawings.

Example 1

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

when the object is at a close distance from infinity, 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.

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

The data for example 1 is as follows:

wherein,

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

d (mm): lens spacing and lens thickness;

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

vd: abbe number of the glass;

focal point distance: 50.9586, respectively;

Fno：2.9

half-picture angle ω: 11.963

F	50.9586	1.95 times of
			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 surface side, a first lens group G1, a second lens group G2 of positive refractive power, a stop, and a third lens group G3 of negative refractive power;

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.

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

The data for example 2 is as follows:

wherein,

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

d (mm): lens spacing and lens thickness;

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

vd: abbe number of the glass;

focal point distance: 66.0242, respectively;

Fno：2.9

half-picture angle ω: 12.1384

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

The condition formula satisfies the condition:

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

The macro lens provided by the invention can form images well from infinity to a magnification of more than 1.5 times, has the advantages of miniaturization, low cost and high magnification, and can be widely applied to the fields of digital camera lenses, video camera lenses, especially interchangeable camera lenses and the like.

The foregoing shows and describes the general principles, essential features, and inventive features of this invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims

1. A high power macro lens, characterized in that, from the object side to the image side, it comprises a first lens group (G1), a second lens group (G2) with positive diopter and diaphragm, and a third lens group (G3) with negative diopter;

wherein, from the object side, the second lens group (G2) is composed of two continuous positive diopter lenses and a plurality of lenses; when 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;

0.2≤|F2/F3|≤0.9 (1)

1.2≤|FL/S2|≤2.5 (2)；

wherein,

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

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

FL: focal length of the entire optical system at infinity;

s2: the maximum moving amount of the second lens group (G2) when the object is at infinity to the maximum photographing magnification.

2. The high power macro lens according to claim 1, wherein said high power macro lens further satisfies:

1.5≤FL/F2≤2.5 (3)

wherein,

FL: focal length of the entire optical system at infinity;

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

3. The high power macro lens according to claim 1, wherein said high power 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: the focal length of the whole optical system in the infinite state.