CN114967068A - Imaging system and optical lens - Google Patents

Imaging system and optical lens Download PDF

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Publication number
CN114967068A
CN114967068A CN202210901650.8A CN202210901650A CN114967068A CN 114967068 A CN114967068 A CN 114967068A CN 202210901650 A CN202210901650 A CN 202210901650A CN 114967068 A CN114967068 A CN 114967068A
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lens
imaging system
imaging
focal length
optical
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CN114967068B (en
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吴沛
周奇明
蒋青锋
蔡显兵
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Zhejiang Huanuokang Technology Co ltd
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Zhejiang Huanuokang Technology Co ltd
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    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B13/00Optical objectives specially designed for the purposes specified below
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B23/00Telescopes, e.g. binoculars; Periscopes; Instruments for viewing the inside of hollow bodies; Viewfinders; Optical aiming or sighting devices
    • G02B23/24Instruments or systems for viewing the inside of hollow bodies, e.g. fibrescopes
    • G02B23/2407Optical details
    • G02B23/2415Stereoscopic endoscopes
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B23/00Telescopes, e.g. binoculars; Periscopes; Instruments for viewing the inside of hollow bodies; Viewfinders; Optical aiming or sighting devices
    • G02B23/24Instruments or systems for viewing the inside of hollow bodies, e.g. fibrescopes
    • G02B23/2407Optical details
    • G02B23/2423Optical details of the distal end
    • G02B23/243Objectives for endoscopes

Abstract

The present invention relates to an imaging system and an optical lens. The imaging system comprises a lens group, a diaphragm and an imaging surface, wherein the lens group consists of a first lens, a second lens, a third lens, a fourth lens and a fifth lens; the diaphragm, the first lens, the second lens, the third lens, the fourth lens, the fifth lens and the imaging surface are sequentially arranged from the object side to the image side along the optical axis; the focal power of the first lens, the second lens, the fourth lens and the fifth lens is positive, and the focal power of the third lens is negative; the imaging system satisfies the following relationship:
Figure 872607DEST_PATH_IMAGE001
(ii) a Wherein the focal length of the second lens is
Figure 352130DEST_PATH_IMAGE002
Focal length of the imaging system is
Figure 788928DEST_PATH_IMAGE003
The field angle of the imaging system is FOV; the imaging system adopts five lenses with different focal powers to be sequentially arranged from the object side to the image side according to a specific sequence, and the imaging system can realize better distortion control and excellent imaging characteristics through distribution and combination of the specific focal powers of the lenses.

Description

Imaging system and optical lens
Technical Field
The invention relates to the technical field of optical imaging, in particular to an imaging system and an optical lens applied to an endoscope.
Background
Thanks to the rapid development of smart medicine in recent years, optical lenses have been rapidly developed in the medical field, especially in the medical endoscope field, but the following problems still exist in the current endoscopic imaging systems and lenses: a. the total length of the optical lens is longer, mostly more than 50mm, and more than 6, 7 or more optical lenses are adopted, so that the size of the lens is larger; b. the imaging target surface is small, most of the imaging target surface is concentrated on 1/2.7 inch and below, and the requirements of the current large target surface camera cannot be met; c. the imaging characteristic is poor, and the requirement of high resolution on the endoscope optical lens at present cannot be supported; d. the temperature stability is low.
Disclosure of Invention
Therefore, it is necessary to provide an imaging system and an optical lens with a small lens size, a large imaging target surface, a good imaging performance and a high temperature stability, aiming at the problems of a large optical lens size, a small imaging target surface, a poor imaging performance and a high temperature stability of the conventional optical lens applied to an endoscope.
The application firstly provides an imaging system, which comprises a lens group, a diaphragm and an imaging surface, wherein the lens group consists of a first lens, a second lens, a third lens, a fourth lens and a fifth lens; the diaphragm, the first lens element, the second lens element, the third lens element, the fourth lens element, the fifth lens element and the image plane are arranged in order from an object side to an image side along an optical axis; the focal power of the first lens, the second lens, the fourth lens and the fifth lens is positive, and the focal power of the third lens is negative; the imaging system satisfies the following relationship:
Figure 705816DEST_PATH_IMAGE001
(ii) a Wherein the focal point of the second lensDistance of
Figure 816860DEST_PATH_IMAGE002
The focal length f of the imaging system and the field angle of the imaging system are FOV.
The imaging system adopts five lenses with different focal powers to be sequentially arranged from the object side to the image side according to a specific sequence, and the imaging system can realize better distortion control and excellent imaging characteristics through distribution and combination of the specific focal powers of the lenses.
In one embodiment, the first lens is a double convex lens, the second lens is a meniscus lens, the third lens is a double concave lens, the fourth lens is a meniscus lens, and the fifth lens is a double convex lens.
In one embodiment, the object-side surface of the second lens element is convex, and the image-side surface of the fourth lens element is convex.
In one embodiment, the imaging system satisfies the following relationship:
Figure 185525DEST_PATH_IMAGE003
(ii) a Wherein the third lens has a central curvature radius towards the image side surface of
Figure 486056DEST_PATH_IMAGE004
The central curvature radius of the fourth lens facing the object side surface is
Figure 240254DEST_PATH_IMAGE005
In one embodiment, the imaging system satisfies the following relationship:
Figure 538511DEST_PATH_IMAGE006
(ii) a Wherein the focal length of the fourth lens is
Figure 660051DEST_PATH_IMAGE007
And the total optical length of the imaging system is TTL.
In one of which is implementedIn one embodiment, the imaging system satisfies the following relationship:
Figure 485312DEST_PATH_IMAGE008
Figure 313591DEST_PATH_IMAGE009
and
Figure 579487DEST_PATH_IMAGE010
(ii) a Wherein the focal length of the first lens is
Figure 453902DEST_PATH_IMAGE011
The focal length of the second lens is
Figure 345504DEST_PATH_IMAGE002
The focal length of the fifth lens is
Figure 559447DEST_PATH_IMAGE012
In one embodiment, the imaging system satisfies the following relationship:
Figure 996245DEST_PATH_IMAGE013
Figure 561219DEST_PATH_IMAGE014
and
Figure 272823DEST_PATH_IMAGE015
(ii) a Wherein the second lens has an Abbe number of
Figure 121699DEST_PATH_IMAGE016
The third lens has an Abbe number of
Figure 932660DEST_PATH_IMAGE017
The fourth lens (24) has an Abbe number of
Figure 250509DEST_PATH_IMAGE018
In one embodiment, the imaging system satisfies the following relationship:
Figure 687175DEST_PATH_IMAGE019
Figure 141290DEST_PATH_IMAGE020
and
Figure 919891DEST_PATH_IMAGE021
(ii) a Wherein the refractive index of the first lens is
Figure 903197DEST_PATH_IMAGE022
The refractive index of the third lens is
Figure 691025DEST_PATH_IMAGE023
The refractive index of the fourth lens is
Figure 999646DEST_PATH_IMAGE024
In one embodiment, the imaging system further comprises a filter positioned between the fifth lens and the imaging surface.
A second aspect of the present application provides an optical lens comprising the imaging system described above.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments or the conventional technologies of the present application, the drawings used in the descriptions of the embodiments or the conventional technologies will be briefly introduced below, it is obvious that the drawings in the following descriptions are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.
FIG. 1 is a schematic view of a lens configuration of an imaging system of the present invention;
fig. 2 is a graph of an optical transfer function (MTF) of the imaging system in a normal temperature state of a visible light band according to the first embodiment of the present invention;
FIG. 3 is a graph of field curvature and distortion of an imaging system in the visible light band according to a first embodiment of the present invention;
FIG. 4 is a diagram of a lateral fan of an imaging system in the visible band according to a first embodiment of the present invention;
FIG. 5 is a dot-column diagram of an imaging system in the visible light band according to a first embodiment of the present invention;
fig. 6 is a graph of an optical transfer function (MTF) of the imaging system of the second embodiment of the present invention in a normal temperature state of a visible light band;
FIG. 7 is a graph of field curvature and distortion in the visible light band for an imaging system according to a second embodiment of the present invention;
FIG. 8 is a diagram of a lateral fan of an imaging system in the visible light band according to a second embodiment of the present invention;
FIG. 9 is a dot-column diagram of an imaging system in a visible light band according to a second embodiment of the present invention;
reference numerals: 10. a diaphragm; 20. a lens group; 21. a first lens; 22. a second lens; 23. a third lens; 24. a fourth lens; 25. a fifth lens; 30. an imaging plane; 40. and (3) a filter.
Detailed Description
In order to make the aforementioned objects, features and advantages of the present application more comprehensible, embodiments accompanying the present application are described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. This application is capable of embodiments in many different forms than those described herein and that modifications may be made by one skilled in the art without departing from the spirit and scope of the application and it is therefore not intended to be limited to the specific embodiments disclosed below.
It will be understood that when an element is referred to as being "secured to" or "disposed" on another element, it can be directly on the other element or intervening elements may also be present. When a component is referred to as being "connected" to another component, it can be directly connected to the other component or intervening components may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like as used in the description of the present application are for illustrative purposes only and do not represent the only embodiments.
Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present application, "plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise.
In this application, unless expressly stated or limited otherwise, the first feature "on" or "under" the second feature may mean that the first feature is in direct contact with the second feature or that the first feature is in indirect contact with the second feature via an intermediate medium. Also, a first feature "on," "over," and "above" a second feature may be directly or diagonally above the second feature, or may simply indicate that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature may be directly under or obliquely under the first feature, or may simply mean that the first feature is at a lesser elevation than the second feature.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in the description of the present application, the term "and/or" includes any and all combinations of one or more of the associated listed items.
Referring to fig. 1, the present application first provides an imaging system, which includes a lens assembly 20, a diaphragm 10 and an image plane 30, wherein the lens assembly 20 includes a first lens 21, a second lens 22, a third lens 23, a fourth lens 24 and a fifth lens 25; the diaphragm 10, the first lens 21, the second lens 22, the third lens 23, the fourth lens 24, the fifth lens 25, and the imaging surface 30 are arranged in order from the object side to the image side along the optical axis; a first lens 21, a second lens 22, a fourth lens 24 andthe focal power of the fifth lens 25 is positive, and the focal power of the third lens 23 is negative; the imaging system satisfies the following relationship:
Figure 198415DEST_PATH_IMAGE001
(ii) a Wherein the focal length of the second lens 22 is
Figure 959698DEST_PATH_IMAGE002
The focal length of the imaging system is f and the field angle of the imaging system is FOV.
The imaging system of the application adopts five lenses with different focal powers to be sequentially arranged from the object side to the image side according to a specific sequence, and the imaging system can realize better distortion control and excellent imaging characteristics through distribution and combination of the specific focal powers of the lenses.
Specifically, the imaging plane size of the imaging system supports a sensor (CCD/CMOS) camera of 1/2 inches at maximum, which satisfies the requirement of high resolution of the device; the total mechanical length of the lens is not more than 32mm, and the size is small; the full field MTF value reaches more than 0.5 under the condition of 100lp/mm, and the imaging characteristic is excellent; the focal power of each lens of the lens is distributed reasonably, the shape of the lens is convenient to process, and the cost of the lens is low; the temperature characteristic of the lens is good, and the imaging performance is not obviously changed at 5-40 ℃.
In addition, the aperture 10 is an aperture diaphragm, the aperture size of the aperture diaphragm determines the aperture value of the system and the depth of field during shooting, the aperture size can be fixed, or the aperture diaphragm with adjustable aperture can be placed as required to achieve the purpose of adjusting the clear aperture, that is, the aperture value of the system can be changed and the depth of field can be changed.
Referring to fig. 1, in some embodiments, the first lens element 21 is a biconvex lens element, the second lens element 22 is a meniscus lens element, the third lens element 23 is a biconcave lens element, the fourth lens element is a meniscus lens element, and the fifth lens element 25 is a biconvex lens element, so as to further improve the imaging quality of the imaging system.
Referring to fig. 1, in some embodiments, the second lens element 22 has a convex surface facing the object-side surface and a concave surface facing the image-side surface, which is favorable for increasing the range of received light and increasing the viewing angle; the fourth lens element 24 has a convex surface facing the image-side surface and a concave surface facing the object-side surface, so as to improve the imaging quality of the imaging system.
In some embodiments, the imaging system satisfies the following relationship:
Figure 20058DEST_PATH_IMAGE003
(ii) a Wherein the third lens 23 has a central radius of curvature toward the image side surface of
Figure 183186DEST_PATH_IMAGE004
The fourth lens element 24 has a central radius of curvature toward the object side of
Figure 100326DEST_PATH_IMAGE005
(ii) a In order to improve the imaging quality of the imaging system.
In some embodiments, the imaging system satisfies the following relationship:
Figure 863752DEST_PATH_IMAGE006
(ii) a Wherein the focal length of the fourth lens 24 is
Figure 462223DEST_PATH_IMAGE007
The total optical length of the imaging system is TTL; to improve the imaging quality of the imaging system.
In some embodiments, the imaging system satisfies the following relationship:
Figure 479858DEST_PATH_IMAGE008
Figure 36741DEST_PATH_IMAGE009
and
Figure 21884DEST_PATH_IMAGE010
(ii) a Wherein the focal length of the first lens 21 is
Figure 689625DEST_PATH_IMAGE011
The focal length of the second lens 22 is
Figure 30608DEST_PATH_IMAGE002
The focal length of the fifth lens 25 is
Figure 276169DEST_PATH_IMAGE012
In some embodiments, the imaging system satisfies the following relationship:
Figure 233761DEST_PATH_IMAGE013
Figure 174035DEST_PATH_IMAGE014
and
Figure 415529DEST_PATH_IMAGE015
(ii) a Wherein the second lens 22 has an Abbe number of
Figure 48636DEST_PATH_IMAGE016
The third lens 23 has an Abbe number of
Figure 759103DEST_PATH_IMAGE017
The fourth lens element 24 has an Abbe number of
Figure 768647DEST_PATH_IMAGE018
(ii) a To reduce the thickness of the lens and the overall length of the imaging system, thereby reducing the size of the imaging system.
Preferably, the imaging system satisfies the following relationship: 35.25 is less than or equal to
Figure 599069DEST_PATH_IMAGE025
≤41.01、
Figure 668656DEST_PATH_IMAGE026
=23.78 and
Figure 397578DEST_PATH_IMAGE027
= 49.61; in the Abbe number range, the imaging system can reduce the thickness of the lens on the premise of ensuring image chromatic aberration and image quality, thereby reducing the size of the imaging system.
In some embodimentsIn (3), the imaging system satisfies the following relationship:
Figure 210813DEST_PATH_IMAGE019
Figure 177632DEST_PATH_IMAGE020
and
Figure 136229DEST_PATH_IMAGE021
(ii) a Wherein the refractive index of the first lens 21 is
Figure 821289DEST_PATH_IMAGE022
The refractive index of the third lens 23 is
Figure 969373DEST_PATH_IMAGE023
The refractive index of the fourth lens 24 is
Figure 790699DEST_PATH_IMAGE024
(ii) a To reduce the thickness of the lens and the overall length of the imaging system, thereby reducing the size of the imaging system.
Preferably, the imaging system satisfies the following relationship:
Figure 670930DEST_PATH_IMAGE028
Figure 829903DEST_PATH_IMAGE029
and
Figure 984941DEST_PATH_IMAGE030
(ii) a Within the refractive index range, the imaging system can reduce spherical aberration and improve imaging quality on one hand, and can reduce the thickness of the lens on the other hand, so that the size of the imaging system is reduced.
Referring to fig. 1, in some embodiments, the imaging system further includes a filter 40, the filter 40 is located between the fifth lens 25 and the imaging plane 30, and the filter 40 is an optical device capable of selecting a desired radiation wavelength band.
A second aspect of the present application provides an optical lens comprising the imaging system described above.
The following exemplifies the lens parameters provided in the first embodiment of the present invention. The radius of curvature R, the center thickness Tc, the refractive index Nd, and the abbe constant Vd of each lens of the imaging system in the first embodiment satisfy the conditions listed in the following table:
Figure 926352DEST_PATH_IMAGE031
note that, in the above table, the mirror surface numbers are the surface numbers of the lenses from left to right in the lens configuration diagram shown in fig. 1, for example: 3 is a surface of the first lens element 21 facing the object side, 4 is a surface of the first lens element 21 facing the image side, 5 is a surface of the second lens element 22 facing the object side, and so on.
Wherein the variable thickness data is as follows:
Figure 508644DEST_PATH_IMAGE032
the imaging system in the first embodiment has the following optical technical indexes: total optical length TTL is less than or equal to 25.0mm, focal length f: 12.62mm, FOV (field angle): 35.8 °, optical distortion: 1.6%, aperture fno.: FNO is less than or equal to 2.0, and the image plane size is as follows: 1/2'.
In the first embodiment, the focal length of the second lens 22
Figure 151983DEST_PATH_IMAGE033
The focal length of the imaging system lens, f =13.3mm, FOV =35.8 °, therefore,
Figure 845133DEST_PATH_IMAGE034
the center radius of curvature R8=19.12mm of the third lens 23 toward the image side surface and the center radius of curvature R9= -43.73mm of the fourth lens 24, and therefore
Figure 641051DEST_PATH_IMAGE035
Focal length of fourth lens 24
Figure 394243DEST_PATH_IMAGE036
And the optical total length TTL of the imaging system satisfies the following conditions:
Figure 993720DEST_PATH_IMAGE037
focal length f1=27.70mm for the first lens 21 and focal length f of the second lens 22
Figure 490561DEST_PATH_IMAGE038
Focal length of fifth lens 25
Figure 937723DEST_PATH_IMAGE039
The abbe number Vd2=35.25 of the glass material of the second lens 22, the abbe number Vd3=23.78 of the glass material of the third lens 23, and the abbe number Vd4=49.61 of the glass material of the fourth lens 24;
the refractive index Nd1=1.73 of the glass material of the first lens 21, the refractive index Nd3=1.84 of the glass material of the third lens 23, and the refractive index Nd4=1.71 of the glass material of the fourth lens 24.
The following exemplifies the lens parameters provided in the second embodiment of the present invention. The radius of curvature R, the center thickness Tc, the refractive index Nd, and the abbe constant Vd of each lens of the imaging system in example two satisfy the conditions listed in the following table:
Figure 861816DEST_PATH_IMAGE040
wherein the variable thickness data is as follows:
Figure 230481DEST_PATH_IMAGE041
the imaging system in the second embodiment has the following optical technical indexes: total optical length TTL is less than or equal to 25.9mm, focal length f: 13.3mm, FOV: 34.1 °, optical distortion: 1.9%, aperture fno.: FNO is less than or equal to 2.0, and the image plane size is as follows: 1/2'.
In the second embodiment, the focal length of the second lens 22
Figure 514700DEST_PATH_IMAGE042
The focal length of the imaging system lens f =13.3mm, FOV =34.1 °, therefore,
Figure 754052DEST_PATH_IMAGE043
the center radius of curvature R8=41.05mm of the third lens 23 toward the image side and the center radius of curvature R9= -35.62mm of the fourth lens 24, and therefore
Figure 849047DEST_PATH_IMAGE044
Focal length of fourth lens 24
Figure 439428DEST_PATH_IMAGE036
And the optical total length TTL of the imaging system satisfies the following conditions:
Figure 530268DEST_PATH_IMAGE045
focal length f1=27.70mm for the first lens 21 and focal length f of the second lens 22
Figure 155285DEST_PATH_IMAGE042
Focal length of fifth lens 25
Figure 217919DEST_PATH_IMAGE046
The abbe number Vd2=41.01 of the glass material of the second lens 22, the abbe number Vd3=23.78 of the glass material of the third lens 23, and the abbe number Vd4=49.61 of the glass material of the fourth lens 24;
the refractive index Nd1=1.73 of the glass material of the first lens 21, the refractive index Nd3=1.85 of the glass material of the third lens 23, and the refractive index Nd4=1.77 of the glass material of the fourth lens 24.
In summary, the first embodiment and the second embodiment respectively satisfy the following relationships:
Figure 295596DEST_PATH_IMAGE047
the imaging systems provided in the first and second embodiments are further described below by analyzing the first and second embodiments in detail.
The optical transfer function is used for evaluating the imaging quality of the imaging system in a more accurate, visual and common mode, the higher and smoother curve of the optical transfer function shows that the imaging quality of the system is better, and various aberrations (such as spherical aberration, coma aberration, astigmatism, field curvature, axial chromatic aberration, vertical axis chromatic aberration and the like) are well corrected.
Referring to fig. 2, an optical transfer function (MTF) graph of the imaging system at normal temperature in the visible light portion is smooth and concentrated, and an average MTF value of a full field of view (half-image height Y' =4.0 mm) is above 0.5; it can be seen that the imaging system provided in this embodiment 1 can meet higher imaging requirements; referring to fig. 6, an optical transfer function (MTF) graph of the imaging system at normal temperature in the visible light portion is smooth and concentrated, and an average MTF value of a full field of view (half-image height Y' =4.0 mm) is above 0.5; it can be seen that the imaging system provided in the embodiment 2 can meet higher imaging requirements.
As shown in fig. 3 and 7, the field curvature of the imaging system is controlled within ± 0.2 mm. The curvature of field is also called as "field curvature". When the lens has field curvature, the intersection point of the whole light beam is not overlapped with an ideal image point, and although a clear image point can be obtained at each specific point, the whole image plane is a curved surface. T represents the meridional field curvature, and S represents the sagittal field curvature. The field curvature curve shows the distance of the current focal plane or image plane to the paraxial focal plane as a function of field coordinates, and the meridional field curvature data is the distance from the currently determined focal plane to the paraxial focal plane measured along the Z axis and measured in the meridional (YZ plane). Sagittal curvature of field data measures distances measured in a plane perpendicular to the meridian plane, the base line in the schematic is on the optical axis, the top of the curve represents the maximum field of view (angle or height), and no units are set on the vertical axis, since the curve is always normalized by the maximum radial field of view.
As shown in fig. 3 and 7, the distortion of the imaging system is better controlled within 2%. Fig. 3 and 7 both refer to multiple wavelength (0.436um, 0.486um, 0.587um, and 0.656um and 0.900um) designs. In general, lens distortion is actually a general term of perspective distortion inherent in an optical lens, that is, distortion due to perspective, and the distortion is very unfavorable for the imaging quality of a photograph, and after all, the purpose of photography is to reproduce rather than exaggerate, but because the distortion is inherent in a lens (converging light rays of a convex lens and diverging light rays of a concave lens), the distortion cannot be eliminated and can only be improved. As can be seen from fig. 3, the distortion of the lens provided in the first embodiment of the present invention is-1.6%; as can be seen from fig. 7, the distortion of the lens provided by the second embodiment of the present invention is-1.9%; the distortion is set to balance the focal length, the field angle and the size of the target surface of the corresponding camera, and the deformation caused by the distortion can be corrected through post image processing.
Referring to fig. 4 and 8, the curves in the sector diagrams are more concentrated, and the spherical aberration and the chromatic dispersion of the imaging system are better controlled.
As shown in fig. 5 and fig. 9, the imaging system has a small and concentrated spot radius, and the corresponding aberration and coma are good.
The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.
The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the claims. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present application shall be subject to the appended claims.

Claims (10)

1. An imaging system, characterized by comprising a lens group (20), a diaphragm (10) and an imaging surface (30), the lens group (20) being composed of a first lens (21), a second lens (22), a third lens (23), a fourth lens (24) and a fifth lens (25);
the diaphragm (10), the first lens (21), the second lens (22), the third lens (23), the fourth lens (24), the fifth lens (25), and the imaging surface (30) are arranged in order from an object side to an image side along an optical axis;
the focal power of the first lens (21), the second lens (22), the fourth lens (24) and the fifth lens (25) is positive, and the focal power of the third lens (23) is negative;
the imaging system satisfies the following relationship:
Figure 834691DEST_PATH_IMAGE001
wherein the focal length of the second lens (22) is
Figure 76185DEST_PATH_IMAGE002
The focal length of the imaging system is f, and the field angle of the imaging system is FOV.
2. The imaging system according to claim 1, characterized in that the first lens (21) is a double convex lens, the second lens (22) is a meniscus lens, the third lens (23) is a double concave lens, the fourth lens is a meniscus lens, and the fifth lens (25) is a double convex lens.
3. The imaging system of claim 2, wherein the second lens (22) is convex toward the object side and the fourth lens (24) is convex toward the image side.
4. The imaging system of claim 3, wherein the imaging system satisfies the relationship:
Figure 709292DEST_PATH_IMAGE003
wherein the third lens (23) has a central radius of curvature toward the image side surface of
Figure 154180DEST_PATH_IMAGE004
The central curvature radius of the fourth lens (24) facing the object side is
Figure 960462DEST_PATH_IMAGE005
5. The imaging system of claim 3, wherein the imaging system satisfies the relationship:
Figure 72774DEST_PATH_IMAGE006
wherein the focal length of the fourth lens (24) is
Figure 860470DEST_PATH_IMAGE007
And the total optical length of the imaging system is TTL.
6. The imaging system of claim 3, wherein the imaging system satisfies the relationship:
Figure 58234DEST_PATH_IMAGE008
Figure 402627DEST_PATH_IMAGE009
and
Figure 369446DEST_PATH_IMAGE010
wherein the first lens (21) has a focal length of
Figure 344355DEST_PATH_IMAGE011
The focal length of the second lens (22) is
Figure 13103DEST_PATH_IMAGE002
The focal length of the fifth lens (25) is
Figure 364450DEST_PATH_IMAGE012
7. The imaging system of claim 3, wherein the imaging system satisfies the relationship:
Figure 982513DEST_PATH_IMAGE013
Figure 393903DEST_PATH_IMAGE014
and
Figure 35100DEST_PATH_IMAGE015
wherein the second lens (22) has an Abbe number of
Figure 176756DEST_PATH_IMAGE016
The third lens (23) has an Abbe number of
Figure 914905DEST_PATH_IMAGE017
The fourth lens (24) has an Abbe number of
Figure 231616DEST_PATH_IMAGE018
8. The imaging system of claim 3, wherein the imaging system satisfies the relationship:
Figure 360109DEST_PATH_IMAGE019
Figure 53259DEST_PATH_IMAGE020
and
Figure 645914DEST_PATH_IMAGE021
wherein the refractive index of the first lens (21) is
Figure 648374DEST_PATH_IMAGE022
The refractive index of the third lens (23) is
Figure 264163DEST_PATH_IMAGE023
The refractive index of the fourth lens (24) is
Figure 495425DEST_PATH_IMAGE024
9. The imaging system of claim 1, further comprising a filter (40), the filter (40) being located between the fifth lens (25) and the imaging surface (30).
10. An optical lens comprising an imaging system according to any one of claims 1 to 9.
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JP2016126133A (en) * 2014-12-26 2016-07-11 日本電産コパル株式会社 Imaging lens and optical device
CN106802465A (en) * 2015-11-26 2017-06-06 三星电机株式会社 Optical imaging system
US20180180853A1 (en) * 2016-12-22 2018-06-28 Samsung Electro-Mechanics Co., Ltd. Optical imaging system
CN113552701A (en) * 2021-08-25 2021-10-26 浙江舜宇光学有限公司 Optical imaging lens
CN217034394U (en) * 2022-03-07 2022-07-22 微创优通医疗科技(上海)有限公司 Endoscope optical system, endoscope objective lens, and endoscope

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2016126133A (en) * 2014-12-26 2016-07-11 日本電産コパル株式会社 Imaging lens and optical device
CN106802465A (en) * 2015-11-26 2017-06-06 三星电机株式会社 Optical imaging system
US20180180853A1 (en) * 2016-12-22 2018-06-28 Samsung Electro-Mechanics Co., Ltd. Optical imaging system
CN113552701A (en) * 2021-08-25 2021-10-26 浙江舜宇光学有限公司 Optical imaging lens
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