CN207067515U - Vision lenses - Google Patents

Abstract

A kind of vision lenses are the utility model is related to, including：First lens, its thing side is close to photographic subjects；Second lens, positioned at the image side of first lens；3rd lens, positioned at the image side of second lens；4th lens, positioned at the image side of the 3rd lens；5th lens, positioned at the image side of the 4th lens；And diaphragm；First lens, the 4th lens and the 5th lens are positive focal length lens, and second lens and the 3rd lens are negative focal length lens.Vision lenses high resolution of the present utility model, optical power are big and optical power scope is wider.

Description

Visual lens

Technical Field

The utility model relates to a vision camera lens especially relates to a machine vision camera lens of constituteing by five lens.

Background

Machine vision refers to the use of a machine to make measurements and judgments instead of the human eye. The machine vision lens captures images, a shot target is converted into image signals through an image shooting device such as an industrial camera, then the signals are calculated through an image processing system, target characteristics such as position, size and appearance are extracted, and a result is output according to preset conditions, so that the functions of automatic identification, judgment, measurement and the like are realized. In recent years, with the rapid development of various industries, machine vision is generally used to replace artificial vision in some dangerous working environments, meanwhile, in the batch operation production process, the efficiency of checking the product quality by the artificial vision is low, the precision is not high, and the production efficiency and the automation degree of production can be greatly improved by using a machine vision detection method.

With the development of the machine vision industry, various machine vision lenses come into the market, but the optical magnification of these machine vision lenses is very small, and usually the optical magnification is kept to be dozens of times or even hundreds of times of the size of an object, and although such a machine vision lens has a wide shooting range, the details of the object in the shooting range cannot be clearly represented, and in the batch operation process or other application occasions, the details of the object to be judged, such as appearance, flaw, size, position, etc., generally need to be judged, and using a lens with a small magnification, the quality of the detailed part of the object to be shot cannot be well judged, and thus the details of the object to be shot need to be judged by using a machine vision lens with a large optical magnification.

Disclosure of Invention

An object of the utility model is to solve the problem among the prior art, provide a high resolution, the big and wide visual lens of optics multiplying power scope of optics multiplying power.

To achieve the above object, the present invention provides a vision lens, including:

a first lens having an object side close to a photographic subject;

a second lens located on an image side of the first lens;

a third lens element on an image side of the second lens element;

a fourth lens element on an image side of the third lens element;

a fifth lens element located on an image side of the fourth lens element; and

a diaphragm;

the first lens, the fourth lens and the fifth lens are positive focal length lenses, and the second lens and the third lens are negative focal length lenses.

According to an aspect of the present invention, the first lens is a convex-concave lens in a direction from an object side to an image side;

the second lens is a convex-concave lens or a concave-convex lens; the third lens is a biconcave lens or a concave-convex lens;

the fourth lens is a biconvex lens or a concave-convex lens;

the fifth lens is a biconvex lens.

According to an aspect of the present invention, when the second lens element is a concave-convex lens element, the second lens element and the third lens element form a cemented lens assembly; or,

when the second lens is a convex-concave lens, the third lens is a biconcave lens and the fourth lens is a biconvex lens, the third lens and the fourth lens form a cemented lens group; or

And when the second lens is a convex-concave lens, the third lens is a concave-convex lens and the fourth lens is a concave-convex lens, the third lens and the fourth lens form a cemented lens group.

According to an aspect of the present invention, when the second lens element and the third lens element form a cemented lens group, the diaphragm is located between the third lens element and the fourth lens element; or,

when the third lens element and the fourth lens element form a cemented lens group, the diaphragm is located between the second lens element and the third lens element.

According to an aspect of the present invention, the visual lens satisfies 0.5 < Mag < 1.25, where Mag represents an optical magnification of the visual lens.

According to an aspect of the utility model, this vision camera lens satisfies 1.85 < TTL EFL < 2.7, and wherein TTL represents the optics total length of vision camera lens, and EFL represents optical lens's focus.

According to an aspect of the present invention, the refractive index and abbe number of the second lens are n2 and v2, respectively, and satisfy the following relational expressions:

0.35＜n2-v2/25＜0.65。

according to an aspect of the present invention, the refractive index and abbe number of the fourth lens are n4 and v4, respectively, and satisfy the following relational expressions:

3.2＜n4+v4/45＜3.5。

according to an aspect of the present invention, the refractive index and abbe number of the fifth lens are n5 and v5, respectively, and satisfy the following relational expressions:

3.4＜n5+v5/45＜3.6。

according to an aspect of the present invention, the anomalous dispersion value of the first lens is dpgf1, and the following relation is satisfied:

11＜1000*dpgf1＜12。

according to an aspect of the present invention, the anomalous dispersion value of the second lens is dpgf2, and the following relation is satisfied:

6＜1000*dpgf2＜10。

according to an aspect of the present invention, the anomalous dispersion value of the fourth lens is dpgf4, and the following relation is satisfied:

28＜1000*dpgf4＜40。

according to an aspect of the present invention, the anomalous dispersion value of the fifth lens is dpgf5, and the following relation is satisfied:

39＜1000*dpgf5＜57。

according to an aspect of the present invention, when the third lens element and the fourth lens element constitute a cemented lens group, the focal length of the second lens element is efy2, the focal length of the cemented lens group constituted by the third lens element and the fourth lens element is efy34, and the following relation is satisfied:

1.7＜efy34/efy2＜3.2。

according to an aspect of the present invention, the focal lengths of the first lens and the fifth lens are efy1 and efy5, respectively, and satisfy the following relation:

1.3＜efy5/efy1＜1.6。

according to an aspect of the present invention, the fifth lens has a center thickness of thic5, and satisfies the following relation:

0.4＜thic5*10/EFL＜0.6。

according to the utility model discloses a vision lens has set gradually five lenses that have just, burden, positive focal length from the thing side to the image side in the camera lens, makes according to the utility model discloses a vision lens's resolution ratio is high, and the big just optics multiplying power scope of optics multiplying power is wider. In addition, this long focus vision camera lens's disadvantage lies in that the colour difference is difficult to the correction, so the utility model discloses vision camera lens structurally adopts the two gauss structures of modified, and is provided with the cemented lens that can eliminate the colour difference at diaphragm A's image side, the colour difference of elimination vision camera lens that can be fine, the distortion of reduction camera lens. And the lenses at the object side and the image side of the diaphragm A are both concave surfaces facing the diaphragm A, so that the aberration of the visual lens can be effectively corrected.

According to the utility model discloses an optical magnification of vision camera lens is Mag, and Mag is < 1.2 more than 0.5. Compared with the traditional visual lens, the optical magnification in the range of 0.5-1.2 is larger and the range of the optical magnification is wider, the optical magnification in the range enables the lens to well capture the details in the ranges of different object surfaces in different sizes, the resolution ratio is higher, the imaging quality is better, and the application range is wider. Furthermore, according to the utility model discloses an each lens arrangement, material are chooseed for use and are distributed more rationally with the focus among the vision lens, and chromatic aberration and aberration that can effectual correction camera lens guarantee that the distortion rate of camera lens is less than 0.1% simultaneously.

Drawings

Fig. 1 schematically shows a schematic view of an arrangement of lenses in a vision lens according to an embodiment of the present invention;

fig. 2 schematically shows an analytical force diagram of a visual shot according to a first embodiment of the invention;

fig. 3 schematically shows a fan diagram of a vision lens according to a first embodiment of the present invention;

fig. 4 schematically shows a stippling diagram of a visual lens according to a first embodiment of the present invention;

fig. 5 schematically shows an on-axis aberration diagram of a vision lens according to a first embodiment of the present invention;

fig. 6 schematically shows a defocus graph of a vision lens according to a first embodiment of the present invention;

fig. 7 schematically shows a distortion diagram of a visual lens according to a first embodiment of the present invention;

fig. 8 schematically shows an analytical force diagram of a visual shot according to a second embodiment of the present invention;

fig. 9 schematically shows a fan diagram of a visual lens according to a second embodiment of the present invention;

fig. 10 schematically shows a stippling diagram of a visual lens according to a second embodiment of the present invention;

fig. 11 schematically shows an on-axis aberration diagram of a vision lens according to a second embodiment of the present invention;

fig. 12 schematically shows a defocus graph of a vision lens according to a second embodiment of the present invention;

fig. 13 schematically shows a distortion diagram of a visual lens according to a second embodiment of the present invention;

fig. 14 schematically shows an analytical force diagram of a visual shot according to a third embodiment of the present invention;

fig. 15 schematically shows a fan diagram of a visual lens according to a third embodiment of the present invention;

fig. 16 schematically shows a stippling diagram of a visual lens according to a third embodiment of the present invention;

fig. 17 schematically shows an on-axis aberration diagram of a vision lens according to a third embodiment of the present invention;

fig. 18 schematically shows a defocus graph of a vision lens according to a third embodiment of the present invention;

fig. 19 schematically shows a distortion diagram of a visual lens according to a third embodiment of the present invention;

fig. 20 schematically shows an analytical force diagram of a visual lens according to a fourth embodiment of the present invention;

fig. 21 schematically shows a fan diagram of a visual lens according to a fourth embodiment of the present invention;

fig. 22 schematically shows a stippling diagram of a visual lens according to a fourth embodiment of the present invention;

fig. 23 schematically shows an on-axis aberration diagram of a vision lens according to a fourth embodiment of the present invention;

fig. 24 schematically shows a defocus graph of a vision lens according to a fourth embodiment of the present invention;

fig. 25 schematically shows a distortion diagram of a visual lens according to a fourth embodiment of the present invention;

fig. 26 schematically shows an arrangement of lenses in a vision lens according to five embodiments of the present invention;

fig. 27 schematically shows an analytical force diagram of a visual lens according to a fifth embodiment of the present invention;

fig. 28 schematically shows a fan diagram of a visual lens according to a fifth embodiment of the present invention;

fig. 29 schematically shows a stippling diagram of a visual lens according to a fifth embodiment of the present invention;

fig. 30 schematically shows an on-axis aberration diagram of a visual lens according to a fifth embodiment of the present invention;

fig. 31 schematically shows a defocus graph of a vision lens according to a fifth embodiment of the present invention;

fig. 32 schematically shows a distortion diagram of a visual lens according to a fifth embodiment of the present invention.

Detailed Description

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the embodiments will be briefly described below. It is obvious that the drawings in the following description are only some embodiments of the invention, and that for a person skilled in the art, other drawings can be derived from them without inventive effort.

In describing embodiments of the present invention, the terms "longitudinal," "lateral," "up," "down," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," and other terms are used in an orientation or positional relationship shown in the associated drawings for convenience in describing the invention and for simplicity in description, and are not intended to indicate or imply that the referenced device or element must have a particular orientation, be constructed and operated in a particular orientation, and are not to be construed as limiting the invention.

The present invention will be described in detail with reference to the accompanying drawings and specific embodiments, which are not repeated herein, but the present invention is not limited to the following embodiments.

Fig. 1 is a view schematically showing a structural arrangement of respective lenses in a vision lens according to an embodiment of the present invention. As shown in fig. 1, the vision lens according to the present invention includes a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, and a stop a. The first lens L1, the second lens L2, the third lens L3, the fourth lens L4, and the fifth lens L5 are disposed in this order from the object side to the image side, that is, the first lens L1 is disposed close to the object, the second lens L2 is disposed on the image side of the first lens L1, the third lens L3 is disposed on the image side of the second lens L2, the fourth lens L4 is disposed on the image side of the third lens L3, and the fifth lens L5 is disposed on the image side of the fourth lens L4. According to the utility model discloses a vision lens, first lens L1 are positive focal length lens, and second lens L2 is negative focal length lens, and third lens L3 is negative focal length lens, and fourth lens L4 is positive focal length lens, and fifth lens L5 is positive focal length lens.

As shown in fig. 1, in the present embodiment, the first lens L1 is a convex-concave lens, and the convex surface of the first lens L1 faces the object side. The second lens element L2 is a convex-concave lens element, and the convex surface of the second lens element L2 faces the object side and the concave surface faces the image side. The third lens L3 is a biconcave lens, and the fourth lens L4 and the fifth lens L5 are each a biconvex lens. In one embodiment of the present disclosure, the third lens element L3 and the fourth lens element L4 are a cemented lens group, i.e., a concave surface of the third lens element L3 facing the image side and a convex surface of the fourth lens element L4 facing the object side are cemented together to form a cemented lens. In the present embodiment, the stop a is provided between the second lens L2 and the third lens L3.

According to another embodiment of the present invention, the first lens L1 is a convex-concave lens, and the convex surface of the first lens L1 faces the object side. The second lens element L2 is a concave-convex lens element, and the concave surface of the second lens element L2 faces the object side and the convex surface faces the image side. The third lens L3 is a biconcave lens, and the fourth lens L4 and the fifth lens L5 are each a biconvex lens. The convex surface of the second lens element L2 facing the image side can be cemented with the concave surface of the third lens element L3 facing the object side, i.e., the second lens element L2 and the third lens element L3 form a cemented lens group. At this time, the stop a is disposed between the third lens L3 and the fourth lens L4.

In addition, according to still another embodiment of the vision lens system of the present invention, when the first lens element L1 is a convex-concave lens element, the second lens element L2 is a convex-concave lens element, the third lens element L3 is a concave-convex lens element, and the fourth lens element L4 is a concave-convex lens element, the third lens element L3 and the fourth lens element L4 constitute a cemented lens group. In the present embodiment, the stop a is provided between the second lens L2 and the third lens L3. According to the utility model discloses a vision lens has set gradually five lenses that have just, burden, just, positive focal length from the thing side to the image side in the camera lens, makes according to the utility model discloses a vision lens's resolution ratio is higher, and the big just optics multiplying power scope of optics multiplying power is wider. In addition, this long focus vision camera lens's disadvantage lies in that the colour difference is difficult to rectify, so the utility model discloses vision camera lens structurally adopts the two gauss structures of modified, and diaphragm A's image side is provided with the cemented lens that can eliminate the colour difference, the colour difference of elimination vision camera lens that can be fine, the distortion of reduction camera lens. And the lenses at the object side and the image side of the diaphragm A are both concave surfaces or non-convex surfaces facing the diaphragm A, so that the aberration of the visual lens can be effectively corrected.

According to the utility model discloses a vision lens, the optics total length TTL of camera lens and the focus EFL of camera lens should satisfy the relation: TTL/EFL is more than 1.85 and less than 2.7. The advantage of setting up like this is when the focus EFL of camera lens is the definite value, can make the camera lens can be to the object plane formation of image of different scopes through the optics total length TTL that changes the camera lens, thereby realizes different optical magnification. The optical magnification of camera lens is the ratio of image space scope and object space scope, and in this embodiment, the optical magnification of camera lens is Mag, according to the utility model discloses an optical magnification of vision camera lens can satisfy: mag is more than 0.5 and less than 1.2. Compared with the traditional visual lens, the optical magnification in the range of 0.5-1.2 is larger and wider in optical magnification range, and the optical magnification in the range can ensure the imaging quality of the detailed part of the shot object. In the embodiment, the size of the image plane of the lens is designed to be phi 16mm, and the optical magnification in the range of 0.5-1.2 can image the object plane in the range of phi 13.3 mm-phi 32mm, so that the lens can well capture the details in the object plane ranges with different sizes, the resolution is higher, the imaging quality is better, and the application range is wider.

As shown in FIG. 1, according to one embodiment of the present invention, the third lens element L3 and the fourth lens element L4 are a cemented lens set, and at this time, the focal lengths of the cemented lens set formed by the first lens element L1, the second lens element L2, the third lens element L3 and the fourth lens element L4 and the fifth lens element L5 of the lens are efy1, efy2, respectively,

efy34, and efy 5. For making the utility model discloses a focal power distribution of each lens is more reasonable in the camera lens, the tolerance distribution is more even to reduce the structure tolerance sensitivity scheduling problem of camera lens, the focus of each lens should satisfy the relation: 1.3 < efy5/efy1 < 1.6; 1.7 < efy34/efy2 < 3.2.

In addition, the focal length of the vision lens according to the utility model is longer, the chromatic aberration correction is more difficult,

in order to better correct chromatic aberration of the lens, the refractive index, abbe number and anomalous dispersion value of the lens should be fully considered. According to the present invention, the refractive index and abbe number of the second lens L2, the fourth lens L4, the fifth lens L5 are n2, n4, n5 and v2, v4, v5, respectively, and the refractive index and abbe number of the lenses should satisfy the relationship: n2-v2/25 is more than 0.35 and less than 0.65; n4+ v4/45 is more than 3.2 and less than 3.5; 3.4 < n5+ v5/45 < 3.6. According to the present invention, the anomalous dispersion values of the first lens L1, the second lens L2, the fourth lens L4, and the fifth lens L5 are dpgf1, dpgf2, dpgf4, and dpgf5, respectively, and the relationships should be satisfied: 11 < 1000 × dpgf1 < 12; 6 < 1000 × dpgf2 < 10; 28 < 1000 × dpgf4 < 40; 39 < 1000 × dpgf5 < 57. To further ensure that chromatic aberration and curvature of field of the lens can be better corrected, the relationship between the thickness of the fifth lens L5 and the lens focal length EFL can be reasonably controlled, the thickness of the fifth lens L5 is thic5, and the relationship between the thickness of the fifth lens L5 and the lens focal length EFL should satisfy: 0.4 < thic5 x 10/EFL < 0.6.

TABLE 1

Table 1 is a table of relevant data of visual shots according to five embodiments of the present invention. Fig. 2 to 7 are schematic diagrams showing an analytical force diagram, a light fan diagram, a point diagram, an on-axis chromatic aberration diagram, a defocus graph, and a distortion diagram of a visual lens according to a first embodiment of the present invention. Fig. 8 to 13 are diagrams schematically showing an analytical force diagram, a light fan diagram, a point diagram, an on-axis chromatic aberration diagram, a defocus graph, and a distortion diagram of a visual lens according to a second embodiment of the present invention. Fig. 14 to 19 are diagrams schematically showing an analytical force diagram, a light fan diagram, a point diagram, an on-axis chromatic aberration diagram, a defocus graph, and a distortion diagram of a visual lens according to a third embodiment of the present invention. Fig. 20 to 25 are diagrams schematically showing an analytical force diagram, a light fan diagram, a point diagram, an on-axis chromatic aberration diagram, a defocus graph, and a distortion diagram of a visual lens according to a fourth embodiment of the present invention. Fig. 26 to 31 are diagrams schematically showing an analytical force diagram, a light fan diagram, a point diagram, an on-axis chromatic aberration diagram, a defocus graph, and a distortion diagram of a visual lens according to a fifth embodiment of the present invention.

According to the first embodiment of the present invention, the focal length EFL of the vision lens is 108.8mm, and the relationship between the thickness thic5 of the fifth lens L5 and the focal length EFL is thic5 × 10/EFL ═ 0.46. The parameters of the lenses in the vision lens are as shown in table 2:

TABLE 2

In the present embodiment, the third lens element L3 and the fourth lens element L4 form a cemented lens group. As shown in table 2, each lens in the lens barrel has a spherical surface, and the radii of curvature of the object-side surface and the image-side surface of the first lens L1 are 49mm and 285mm, respectively. The radii of curvature of the object-side surface and the image-side surface of the second lens L2 are 72mm and 30mm, respectively. The radius of curvature of the object-side surface of the third lens L3 is-25 mm, the radius of curvature of the image-side surface of the fourth lens L4 is-30 mm, and the radius of curvature of the cemented portion of the image-side concave surface of the third lens L3 and the object-side convex surface of the fourth lens L4 is 90 mm. The radius of curvature of the object-side convex surface of the fifth lens L5 may be infinite, and the radius of curvature of the image-side convex surface is-40 mm. In this embodiment, the focal length of each lens in the visual lens is efy 1-60.34, efy 2-69.89, efy 34-143.7, efy 5-84.12. efy5/efy1 equals 1.39, efy34/efy2 equals 2.06. 1000 × dpgf1, 1000 × dpgf2, 1000 × dpgf4 and 1000 × dpgf5 were 11.3, 9.8, 37.5 and 39.8, respectively. n2-v2/25 is 0.64, n4+ v4/45 is 3.3, and n5+ v5/45 is 3.45. As can be seen from tables 1 and 2, the refractive index, abbe number and anomalous dispersion value of each lens in the lens all satisfy the requirements of the lens according to the present invention. Because the focal length EFL of the lens is a constant value of 108.8mm, the object distance can be changed by changing the value of TTL/EFL, namely changing the total optical length TTL of the lens, thereby changing the optical magnification of the lens. The corresponding relationship between the optical magnification of the lens and the object distance, the total optical length of the lens, TTL and TTL/EFL is shown in Table 3:

optical magnification	1.2X	1X	0.9X	0.8X	0.7X	0.6X	0.5X
								Object distance (mm)	162.7	181	193	208	227	253	28
TTL	280	258	247	236	226	215	204
								TTL/EFL	2.57	2.37	2.27	2.17	2.08	1.98	1.88

TABLE 3

Referring to fig. 2-7, fig. 2-7 are an analytic force diagram, a fan diagram, a point diagram, an on-axis chromatic aberration diagram, a defocusing curve diagram and a distortion diagram when the working object distance of the visual lens is 162.7-288 mm, the focal length is 108.8mm, and the optical magnification is 0.5-1.2. As can be seen from the figure, the visual lens according to the embodiment has higher resolving power, i.e. better presentation of imaging details, the on-axis aberration is controlled within a range of-0.05 mm to 0.15mm, the lens defocus (i.e. the lens depth of focus) is controlled within a range of-0.1 mm to 0.1mm, and the distortion rate is within-0.04% compared with the conventional visual lens. Therefore, the visual lens according to the first embodiment of the present invention satisfies the requirements of high resolution, large optical magnification, easy correction of chromatic aberration, and low distortion.

According to the second embodiment of the present invention, the focal length EFL of the vision lens is 110.3mm, and the relationship between the thickness thic5 of the fifth lens element L5 and the focal length EFL is thic5 × 10/EFL ═ 0.453. The parameters of the lenses in the vision lens are as shown in table 4:

surface type	Radius of curvature	Thickness of	Material (refractive index/Abbe number)	dpgf*1000
					Spherical surface	40.1	3.7	2.0/25	11.1
Spherical surface	288.9	0.1
					Spherical surface	164.4	2.7	1.67/32	8.8
Spherical surface	25	6
					Spherical surface	-20.8	0.85	1.57/42
Spherical surface	55.8	4.6	1.5/81	28.7
					Spherical surface	-26.2	14
Spherical surface	322	5	1.44/95	56.4
					Spherical surface	-35.2	230.6

TABLE 4

In the present embodiment, the third lens element L3 and the fourth lens element L4 form a cemented lens group. As shown in table 4, each lens in the lens barrel has a spherical surface, and the radii of curvature of the object-side surface and the image-side surface of the first lens L1 are 40.1mm and 288.9mm, respectively. The radii of curvature of the object-side surface and the image-side surface of the second lens L2 are 164.4mm and 25mm, respectively. The radius of curvature of the object-side surface of the third lens L3 is-20.8 mm, the radius of curvature of the image-side surface of the fourth lens L4 is-26.2 mm, and the radius of curvature of the cemented portion of the concave surface on the image side of the third lens L3 and the convex surface on the object side of the fourth lens L4 is 55.8 mm. The radii of curvature of the object-side and image-side surfaces of the fifth lens L5 are 322mm and-35.2 mm, respectively. In this embodiment, the focal length of each lens in the visual lens is efy 1-46.22, efy 2-44.24, efy 34-129.1, efy 5-73. efy5/efy1 is 1.58, efy34/efy2 is 2.92, 1000 × dppf 1, 1000 × dppf 2, 1000 × dppf 4 and 1000 × dppf 5 are 11.1, 8.8, 28.7 and 56.4, respectively. n2-v2/25 is 0.39, n4+ v4/45 is 3.3, and n5+ v5/45 is 3.55. As can be seen from tables 1 and 4, the refractive index, abbe number and anomalous dispersion value of each lens in the lens all satisfy the requirements of the lens according to the present invention. Because the focal length EFL of the lens is a fixed value of 110.3mm, the object distance can be changed by changing the value of TTL/EFL, namely changing the total optical length TTL of the lens, thereby changing the optical magnification of the lens. The corresponding relationship between the optical magnification of the lens and the object distance, the total optical length of the lens, TTL and TTL/EFL is shown in Table 5:

optical magnification	1.2X	1X	0.9X	0.8X	0.7X	0.6X	0.5X
								Object distance (mm)	161	180	192	207	227	253	290
TTL	289.8	267.6	256.8	245.9	234.6	223.7	212.5
								TTL/EFL	2.63	2.43	2.33	2.23	2.13	2.03	1.93

TABLE 5

Referring to fig. 8-13, fig. 8-13 are an analytic force diagram, a fan diagram, a dot array diagram, an on-axis chromatic aberration diagram, a defocus graph and a distortion diagram of a visual lens with an operating object distance of 161-290 mm, a focal length of 110.3mm and an optical magnification of 0.5-1.2. As can be seen from the figure, the visual lens according to the embodiment has higher resolving power, i.e. better presentation of imaging details, the on-axis aberration is controlled within a range of-0.05 mm to 0.15mm, the lens defocus (i.e. the lens depth of focus) is controlled within a range of-0.1 mm to 0.05mm, and the distortion rate is within-0.06%, compared with the conventional visual lens. Therefore, the visual lens according to the second embodiment of the present invention also satisfies the requirements of high resolution, large optical magnification, easy correction of chromatic aberration, and low distortion.

According to the third embodiment of the present invention, the focal length EFL of the vision lens is 110mm, and the relationship between the thickness thic5 of the fifth lens L5 and the focal length EFL is thic5 × 10/EFL ═ 0.445. The parameters of the lenses in the vision lens are as shown in table 6:

surface type	Radius of curvature	Thickness of	Material (refractive index/Abbe number)	dpgf*1000
					Spherical surface	44.5	3.7	2/25	11.7
Spherical surface	629.8	0.11
					Spherical surface	203.4	2.7	1.67/32	8.8
Spherical surface	27.1	6.1
					Spherical surface	-21.1	0.85	1.57/43
Spherical surface	61.3	4.6	1.5/82	28.7
					Spherical surface	-26.3	14
Spherical surface	301.7	4.9	1.44/95	46.1
					Spherical surface	-36.7	229.3

TABLE 6

In the present embodiment, the third lens element L3 and the fourth lens element L4 form a cemented lens group. As shown in table 6, each lens in the lens barrel has a spherical surface, and the radii of curvature of the object-side surface and the image-side surface of the first lens L1 are 44.5mm and 629.8mm, respectively. The radii of curvature of the object-side surface and the image-side surface of the second lens L2 are 203.4mm and 27.1mm, respectively. The radius of curvature of the object-side surface of the third lens L3 is-21.1 mm, the radius of curvature of the image-side surface of the fourth lens L4 is-26.3 mm, and the radius of curvature of the cemented portion of the concave surface on the image side of the third lens L3 and the convex surface on the object side of the fourth lens L4 is 61.3 mm. The radii of curvature of the object-side surface and the image-side surface of the fifth lens L5 are 301.7mm and-36.7 mm, respectively. In this embodiment, the focal length of each lens in the visual lens is efy1 ═ 47.7, efy2 ═ -46.7, efy34 ═ 134.45, and efy5 ═ 75, respectively. efy5/efy1 equals 1.57, efy34/efy2 equals 2.88. 1000 × dpgf1, 1000 × dpgf2, 1000 × dpgf4 and 1000 × dpgf5 were 11.7, 8.8, 28.7 and 46.1, respectively. n2-v2/25 is 0.39, n4+ v4/45 is 3.32, and n5+ v5/45 is 3.55. As can be seen from tables 1 and 6, the refractive index, Abbe number and the abnormal dispersion value of each lens in the lens all satisfy the basis the utility model discloses a lens can change the object distance through changing the value of TTL/EFL because the focus EFL of lens is the definite value 110mm to the relevant requirement of each lens, changes the optics total length TTL of lens promptly, and then changes the optical magnification of lens. The corresponding relationship between the optical magnification of the lens and the object distance, the total optical length of the lens, TTL and TTL/EFL is shown in Table 7:

optical magnification	1.2X	1X	0.9X	0.8X	0.7X	0.6X	0.5X
								Object distance (mm)	161.5	180	192	207	227	252	288
TTL	288.4	266.2	255.4	244.5	233.3	222.7	211.7
								TTL/EFL	2.62	2.42	2.32	2.22	2.12	2.02	1.92

TABLE 7

Referring to fig. 14-19, fig. 14-19 are an analytic force diagram, a fan diagram, a dot diagram, an on-axis chromatic aberration diagram, a defocus graph and a distortion diagram of a visual lens with an object working distance of 161.5-288 mm, a focal length of 110mm and an optical magnification of 0.5-1.2. As can be seen from the figure, the visual lens according to the embodiment has higher resolving power, i.e. better presentation of imaging details, the on-axis aberration is controlled within a range of-0.05 mm to 0.17mm, the lens defocus (i.e. the lens depth of focus) is controlled within a range of-0.1 mm to 0.06mm, and the distortion rate is within-0.06%, compared with the conventional visual lens. Therefore, the vision lens according to the third embodiment of the present invention also satisfies the requirements of high resolution, large optical magnification, easy correction of chromatic aberration, and low distortion.

According to the fourth embodiment of the present invention, the focal length EFL of the vision lens is 108.3mm, and the relationship between the thickness thic5 of the fifth lens element L5 and the focal length EFL is thic5 × 10/EFL ═ 0.454. The parameters of the lenses in the vision lens are as shown in table 8:

surface type	Radius of curvature	Thickness of	Material (refractive index/Abbe number)	dpgf*1000
					Spherical surface	41	4.2	2/25	11.1
Spherical surface	183	0.1
					Spherical surface	76.7	2.8	1.69/31	6.3
Spherical surface	25.8	6.1
					Spherical surface	-23.4	0.85	1.57/43
Spherical surface	50.7	4.4	1.46/90	39.8
					Spherical surface	-29.2	13.7
Spherical surface	253.1	4.92	1.44/95	46.1
					Spherical surface	-35.8	221.2

TABLE 8

In the present embodiment, the third lens element L3 and the fourth lens element L4 form a cemented lens group. As shown in table 8, each lens in the lens barrel has a spherical surface, and the radii of curvature of the object-side surface and the image-side surface of the first lens L1 are 41mm and 183mm, respectively. The radii of curvature of the object-side surface and the image-side surface of the second lens L2 are 76.7mm and 25.8mm, respectively. The radius of curvature of the object-side surface of the third lens L3 is-23.4 mm, the radius of curvature of the image-side surface of the fourth lens L4 is-29.2 mm, and the radius of curvature of the cemented portion of the concave surface on the image side of the third lens L3 and the convex surface on the object side of the fourth lens L4 is 50.7 mm. The radii of curvature of the object-side surface and the image-side surface of the fifth lens L5 are 253.1mm and-35.8 mm, respectively. In this embodiment, the focal length of each lens in the visual lens is efy1 ═ 53.2, efy2 ═ -57.8, efy34 ═ 105.2, and efy5 ═ 72. efy5/efy1 equals 1.35, efy34/efy2 equals 1.82. 1000 × dpgf1, 1000 × dpgf2, 1000 × dpgf4 and 1000 × dpgf5 are 11.1, 6.3, 39.8 and 46.1, respectively. n2-v2/25 is 0.45, n4+ v4/45 is 3.46, and n5+ v5/45 is 3.55. As can be seen from tables 1 and 8, the refractive index, abbe number and anomalous dispersion value of each lens in the lens all satisfy the requirements of the lens according to the present invention. Because the focal length EFL of the lens is a constant value of 108.3mm, the object distance can be changed by changing the value of TTL/EFL, namely changing the total optical length TTL of the lens, thereby changing the optical magnification of the lens. The corresponding relationship between the optical magnification of the lens and the object distance, the total optical length of the lens, TTL and TTL/EFL is shown in Table 9:

optical magnification	1.2X	1X	0.9X	0.8X	0.7X	0.6X	0.5X
								Object distance (mm)	161	179	191	206	225	251	287
TTL	280	258	247	236	225.6	214.6	203.7
								TTL/EFL	2.59	2.38	2.28	2.18	2.08	1.98	1.88

TABLE 9

Referring to fig. 20-25, fig. 20-25 are an analytic force diagram, a fan diagram, a dot diagram, an on-axis chromatic aberration diagram, a defocus graph and a distortion diagram of a visual lens with an object working distance of 161-287 mm, a focal length of 108.3mm and an optical magnification of 0.5-1.2. As can be seen from the figure, compared with the conventional visual lens, the visual lens according to the embodiment has higher resolving power, i.e. better presentation of imaging details, the on-axis aberration is controlled within the range of 0mm to 0.1mm, the lens defocus is controlled within the range of-0.1 mm to 0.06mm, and the distortion rate is within-0.06%. It can be seen that the vision lens according to the fourth embodiment of the present invention also satisfies the requirements of high resolution, large optical magnification, easy correction of chromatic aberration, and low distortion.

Fig. 26 schematically shows a structural arrangement diagram of each lens in a visual lens according to a fifth embodiment of the present invention. As shown in fig. 26, the structures of the third lens L3 and the fourth lens L4 in the visual lens system according to the fifth embodiment of the present invention are different from those of the first four embodiments, in which the third lens L3 is a biconcave lens and the fourth lens L4 is a biconvex lens. In the present embodiment, the third lens L3 and the fourth lens L4 are both meniscus lenses, i.e., the object-side surface is concave and the image-side surface is convex. In this arrangement, third lens L3 and fourth lens L4 may still form a cemented lens group.

According to the fifth embodiment of the present invention, the focal length EFL of the vision lens is 108mm, and the relationship between the thickness thic5 of the fifth lens L5 and the focal length EFL is thic5 × 10/EFL ═ 0.454. The parameters of the lenses in the vision lens are shown in table 10:

surface type	Radius of curvature	Thickness of	Material (refractive index/Abbe number)	dpgf*1000
					Spherical surface	57.7	4	2/25	11.1
Spherical surface	693.7	0.1
					Spherical surface	65.6	2.9	1.75/28	9.8
Spherical surface	29.3	6
					Spherical surface	-20.5	0.8	1.65/40
Spherical surface	-118.8	4.5	1.5/82	28.7
					Spherical surface	-23	13.5
Spherical surface	1235	4.8	1.44/95	46.1
					Spherical surface	-38	220

Watch 10

In the present embodiment, the third lens element L3 and the fourth lens element L4 form a cemented lens group. As shown in table 10, each lens in the lens barrel has a spherical surface, and the radii of curvature of the object-side surface and the image-side surface of the first lens L1 are 57.7mm and 693.7mm, respectively. The radii of curvature of the object-side surface and the image-side surface of the second lens L2 are 65.6mm and 29.3mm, respectively. The radius of curvature of the object-side surface of the third lens L3 is-20.5 mm, the radius of curvature of the image-side surface of the fourth lens L4 is-23 mm, and the radius of curvature of the cemented portion of the convex surface on the image side of the third lens L3 and the concave surface on the object side of the fourth lens L4 is-118.8 mm. The radii of curvature of the object-side surface and the image-side surface of the fifth lens L5 are 1235mm and-38 mm, respectively. In this embodiment, the focal length of each lens in the visual lens is efy 1-63, efy 2-74, efy 34-143, efy 5-85. efy5/efy1 equals 1.35, efy34/efy2 equals 1.93. 1000 × dpgf1, 1000 × dpgf2, 1000 × dpgf4 and 1000 × dpgf5 are 11.1, 9.8, 28.7 and 46.1, respectively. n2-v2/25 is 0.63, n4+ v4/45 is 3.32, and n5+ v5/45 is 3.55. As can be seen from tables 1 and 10, the refractive index, abbe number, and anomalous dispersion value of each lens in the lens all satisfy the requirements of the lens according to the present invention. Because the focal length EFL of the lens is a constant value of 108mm, the object distance can be changed by changing the value of TTL/EFL, namely changing the total optical length TTL of the lens, thereby changing the optical magnification of the lens. The corresponding relationship between the optical magnification of the lens and the object distance, the total optical length of the lens, TTL and TTL/EFL is shown in table 11:

optical magnification	1.2X	1X	0.9X	0.8X	0.7X	0.6X	0.5X
								Object distance (mm)	162	180	192	207	227	252	288
TTL	278	257	246	235	224	213	202
								TTL/EFL	2.57	2.38	2.28	2.18	2.07	1.97	1.87

TABLE 11

Referring to fig. 27-32, fig. 27-32 are an analytical force diagram, a light fan diagram, a dot array diagram, an on-axis chromatic aberration diagram, a defocus graph and a distortion diagram when the working object distance of the visual lens is 162-288 mm, the focal length is 108mm, and the optical magnification is 0.5-1.2. As can be seen from the figure, the visual lens according to the embodiment has higher resolving power, i.e. better presentation of imaging details, the on-axis aberration is controlled within the range of-0.05 mm to 0.15mm, the lens defocus is controlled within the range of-0.1 mm to 0.1mm, and the distortion rate is within-0.05% compared with the conventional visual lens. Therefore, the visual lens according to the fifth embodiment of the present invention also satisfies the requirements of high resolution, large optical magnification, easy correction of chromatic aberration, and low distortion.

The foregoing is illustrative of embodiments of the present invention and is to be understood that the invention may be practiced otherwise than as specifically described herein.

The above description is only one embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (16)

1. A vision lens, comprising:

a first lens (L1) having an object side close to a photographic subject;

a second lens (L2) located on the image side of the first lens (L1);

a third lens (L3) located on the image side of the second lens (L2);

a fourth lens (L4) located on the image side of the third lens (L3);

a fifth lens (L5) located on the image side of the fourth lens (L4); and

a diaphragm (A); it is characterized in that the preparation method is characterized in that,

the first lens (L1), the fourth lens (L4), and the fifth lens (L5) are positive focal length lenses, and the second lens (L2) and the third lens (L3) are negative focal length lenses.

2. A vision lens according to claim 1, characterized in that, in a direction from an object side to an image side, the first lens (L1) is a convex-concave lens;

the second lens (L2) is a convex-concave lens or a concave-convex lens;

the third lens (L3) is a biconcave lens or a concave-convex lens;

the fourth lens (L4) is a biconvex lens or a concave-convex lens;

the fifth lens (L5) is a biconvex lens.

3. A vision lens according to claim 2, characterized in that when said second lens (L2) is a concave-convex lens, said second lens (L2) and said third lens (L3) constitute a cemented lens group; or,

when the second lens element (L2) is a convex-concave lens element, the third lens element (L3) is a biconcave lens element, and the fourth lens element (L4) is a biconvex lens element, the third lens element (L3) and the fourth lens element (L4) form a cemented lens group; or,

when the second lens (L2) is a convex-concave lens, the third lens (L3) is a concave-convex lens, and the fourth lens (L4) is a concave-convex lens, the third lens (L3) and the fourth lens (L4) form a cemented lens group.

4. A vision lens according to claim 3, characterized in that said stop (A) is located between said third lens (L3) and said fourth lens (L4) when said second lens (L2) and said third lens (L3) constitute a cemented lens group; or,

when the third lens (L3) and the fourth lens (L4) form a cemented lens group, the stop (A) is located between the second lens (L2) and the third lens (L3).

5. A visual lens according to any one of claims 1 to 4, wherein the visual lens satisfies 0.5 < Mag < 1.25, where Mag represents the optical power of the visual lens.

6. An optical lens as claimed in any one of claims 1 to 4, wherein the optical lens satisfies 1.85 < TTL/EFL < 2.7, where TTL represents the total optical length of the optical lens and EFL represents the focal length of the optical lens.

7. A vision lens according to one of claims 1 to 4, characterized in that said second lens (L2) has a refractive index and an Abbe number n2 and v2, respectively, and satisfies the following relation:

0.35＜n2-v2/25＜0.65。

8. a vision lens according to one of claims 1 to 4, characterized in that said fourth lens (L4) has a refractive index and an Abbe number n4 and v4, respectively, and satisfies the following relation:

3.2＜n4+v4/45＜3.5。

9. a vision lens according to one of claims 1 to 4, characterized in that the refractive index and Abbe number of the fifth lens (L5) are n5 and v5, respectively, and satisfy the following relation:

3.4＜n5+v5/45＜3.6。

10. a vision lens according to one of the claims 1 to 4, characterized in that said first lens (L1) has an anomalous dispersion value of dpgf1 and satisfies the following relation:

11＜1000*dpgf1＜12。

11. a vision lens according to one of the claims 1 to 4, characterized in that said second lens (L2) has an anomalous dispersion value of dpgf2 and satisfies the following relation:

6＜1000*dpgf2＜10。

12. a vision lens according to one of the claims 1 to 4, characterized in that said fourth lens (L4) has an anomalous dispersion value of dpgf4 and satisfies the following relation:

28＜1000*dpgf4＜40。

13. a vision lens according to one of the claims 1 to 4, characterized in that said fifth lens (L5) has an anomalous dispersion value of dpgf5 and satisfies the following relation:

39＜1000*dpgf5＜57。

14. a vision lens according to one of claims 1 to 4, characterized in that, when said third lens (L3) and said fourth lens (L4) constitute a cemented lens group, the focal length of said second lens (L2) is efy2, the focal length of said cemented lens group constituted by said third lens (L3) and said fourth lens (L4) is efy34, and the following relation is satisfied:

1.7＜efy34/efy2＜3.2。

15. a visual lens according to one of claims 1 to 4, characterised in that the focal lengths of the first lens (L1) and the fifth lens (L5) are efy1 and efy5, respectively, and satisfy the following relation:

1.3＜efy5/efy1＜1.6。

16. a vision lens according to one of claims 1 to 4, characterized in that said fifth lens (L5) has a central thickness thic5 and satisfies the following relation:

0.4＜thic5*10/EFL＜0.6。