CN218158511U - Imaging system - Google Patents

Imaging system Download PDF

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CN218158511U
CN218158511U CN202221830359.8U CN202221830359U CN218158511U CN 218158511 U CN218158511 U CN 218158511U CN 202221830359 U CN202221830359 U CN 202221830359U CN 218158511 U CN218158511 U CN 218158511U
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lens
imaging system
image
spacer element
optical axis
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肖尧鑫
励维芳
金银芳
张兰兰
戴付建
赵烈烽
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Zhejiang Sunny Optics Co Ltd
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Zhejiang Sunny Optics Co Ltd
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Abstract

The application discloses imaging system, including lens group, a plurality of interval component and lens-barrel, the lens group includes in proper order from the thing side to the image side along the optical axis: the lens group comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens, wherein the number of the lenses with focal power in the lens group is six, the first lens has negative focal power, the second lens has positive focal power, and the third lens has negative focal power; the plurality of spacer elements include first to fifth spacer elements, wherein an outer diameter of an object side end of the lens barrel is smaller than an outer diameter of an image side end thereof, and the imaging system satisfies: 5.0< (f/TD) + (L/∑ CP) <52.0; wherein f is the total effective focal length of the imaging system, L is the dimension of the lens barrel along the optical axis, TD is the distance along the optical axis from the object side surface of the first lens to the image side surface of the sixth lens, and Σ CP is the sum of the maximum thicknesses of the spacing elements in the first spacing element to the fifth spacing element.

Description

Imaging system
Technical Field
The present application relates to the field of optical elements, and in particular, to an imaging system.
Background
In recent years, with the continuous increase of the popularity of the concept of the metasequoia, people are interested in the Virtual world and the combined experience of the Virtual world and the real world, and thus the exploration of the Augmented Reality technology (AR) and the Virtual Reality technology (VR) is stimulated.
Imaging lenses applied in AR or VR application scenes such as environmental perception, spatial positioning, gesture manipulation, and the like generally need to have the characteristics of wide shooting angle and many application scenes, so the above application fields pay much attention to optical angle lenses. The size of wide-angle lenses on the market is generally large; in addition, in the imaging lens including five lenses or more, a problem of assembly stability due to a large step difference between the lenses occurs. Moreover, the edge of the lens is easy to generate stray light phenomenon along with the increase of the image plane. The above-mentioned problems of stray light and assembly stability seriously affect the imaging quality of the imaging lens.
Therefore, how to reasonably set the structures and optical parameters of the imaging lens and the lens barrel and the structural relationship between the lens and the spacing element included in the imaging lens, so as to improve the problem of stray light and ensure the assembly stability of the imaging lens on the premise of realizing wide angle and miniaturization is a problem to be solved in the field.
It should be appreciated that this background section is intended, in part, to provide a useful background for understanding the technology, however, such content is not necessarily what is known or understood by those skilled in the art prior to the filing date of the present application.
SUMMERY OF THE UTILITY MODEL
The application provides an imaging system, including lens battery, a plurality of interval components and be used for holding the lens battery and the lens cone of a plurality of interval components, the lens battery includes from the object side to the image side in order along the optical axis: the lens comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens, wherein the number of the lenses with focal power in the lens group is six, and the first lens has negative focal power; the second lens has a positive optical power, and the third lens has a negative optical power; the plurality of spacing elements comprises: a first spacer element in contact with an image side portion of the first lens; a second spacer element in contact with an image-side surface portion of the second lens; a third spacer element in contact with an image side portion of the third lens; a fourth spacer element in contact with an image-side surface portion of the fourth lens; and a fifth spacer element in contact with an image-side surface portion of the fifth lens; wherein an outer diameter of an object side end of the lens barrel is smaller than an outer diameter of an image side end thereof, and the imaging system satisfies: 5.0< (f/TD) + (L/∑ CP) <52.0; wherein f is a total effective focal length of the imaging system, L is a dimension of the lens barrel along the optical axis direction, TD is a distance along the optical axis from an object side surface of the first lens to an image side surface of the sixth lens, and Σ CP is a sum of maximum thicknesses of the respective spacing elements of the first spacing element to the fifth spacing element.
In one embodiment of the present application, the imaging system satisfies: R3/R4<0, and R3/R6>0; wherein R3 is a radius of curvature of an object-side surface of the second lens element, R4 is a radius of curvature of an image-side surface of the second lens element, and R6 is a radius of curvature of an image-side surface of the third lens element.
In one embodiment of the present application, the imaging system satisfies: f4/f5<0, wherein f4 is the focal power of the fourth lens, and f5 is the focal power of the fifth lens.
In one embodiment of the present application, the fifth lens is a meniscus lens.
In one embodiment of the present application, a material of the fourth lens is glass.
In one embodiment of the present application, the imaging system satisfies: -18.5< (f 3+ f 2)/(D3 s-D2 m) < -8.5, wherein f3 is the effective focal length of the third lens, f2 is the effective focal length of the second lens, D3s is the outer diameter of the object side face of the third spacer element, and D2m is the outer diameter of the image side face of the second spacer element.
In one embodiment of the application, the object side surface of the third spacer element has an outer diameter equal to the outer diameter of the image side surface, and the object side surface of the third spacer element has an inner diameter equal to the inner diameter of the image side surface.
In one embodiment of the present application, the plurality of spacer elements further comprises: a sixth spacing element in contact with the image side portion of the second spacing element.
In one embodiment of the present application, the imaging system satisfies: 3.0N ct4/(CP 3+ CP 4) × N4<45.0, wherein CT4 is the central thickness of the fourth lens, CP3 is the maximum thickness of the third spacer element, CP4 is the maximum thickness of the fourth spacer element, and N4 is the refractive index of the fourth lens.
In one embodiment of the present application, the imaging system satisfies: -7.4< (d 2bs-d2 bm)/T23 + f2/CT2<5.5, wherein d2bm is the inner diameter of the image side surface of the sixth spacing element, d2bs is the inner diameter of the object side surface of the sixth spacing element, T23 is the air gap between the second lens and the third lens along the optical axis, f2 is the effective focal length of the second lens, and CT2 is the center thickness of the second lens.
In one embodiment of the present application, the imaging system satisfies: l (CT 2-EP 12)/(T23-CP 2) | <10.0, where CT2 is the center thickness of the second lens, EP12 is the distance between the image-side surface of the first spacer element and the object-side surface of the second spacer element along the optical axis, T23 is the air gap between the second lens and the third lens along the optical axis, and CP2 is the maximum thickness of the second spacer element.
In one embodiment of the present application, the imaging system satisfies: -16.5< (D1 m-D1 s)/(CT 1-T12-CP 1) < -0.5, wherein D1m is the outer diameter of the image side surface of the first spacer element, D1s is the inner diameter of the object side surface of the first spacer element, CT1 is the center thickness of the first lens, T12 is the air gap between the first and second lenses along the optical axis, and CP1 is the maximum thickness of the first spacer element.
In one embodiment of the present application, the imaging system satisfies: 2.5< (D2 s/D2 m) + (R3/CT 2) <7.0, wherein D2s is the outer diameter of the object side face of the second spacer element, D2m is the inner diameter of the image side face of the second spacer element, R3 is the radius of curvature of the object side face of the second lens, CT2 is the central thickness of the second lens.
In one embodiment of the present application, the imaging system satisfies: 0< (T23 + T34)/(CP 1+ CP 2) <10.0, wherein T23 is an air gap between the second lens and the third lens along the optical axis, T34 is an air gap between the third lens and the fourth lens along the optical axis, CP1 is a maximum thickness of the first spacer element, and CP2 is a maximum thickness of the second spacer element.
In one embodiment of the present application, the imaging system satisfies: 9.5< (CT 4+ EP 23)/(EP 34-CT 3) <17.4, wherein CT4 is a central thickness of the fourth lens, EP23 is a distance along the optical axis between an image-side surface of the second spacer element and an object-side surface of the third spacer element, CT3 is a central thickness of the third lens, and EP34 is a distance along the optical axis between an image-side surface of the third spacer element and an object-side surface of the fourth spacer element.
In one embodiment of the present application, the imaging system satisfies: -41.5mm -1 <(d4m-d4s+D4s)/(R8*T45)<-9.0mm -1 Wherein d4m is of said fourth spacer elementAn inner diameter of an image-side surface, D4s is an inner diameter of an object-side surface of the fourth lens element, D4s is an outer diameter of an object-side surface of the fourth spacer element, R8 is a radius of curvature of the image-side surface of the fourth lens element, and T45 is an air gap between the fourth lens element and the fifth lens element along the optical axis.
In one embodiment of the present application, the imaging system satisfies: 0< (R10 + R11) > FNO/(D5 s-D4 m) <8.0, wherein R10 is a radius of curvature of an image side surface of the fifth lens, R11 is a radius of curvature of an object side surface of the sixth lens, FNO is an aperture value of the imaging system, D5s is an outer diameter of an object side surface of the fifth spacing element, and D4m is an outer diameter of an image side surface of the fourth spacing element.
In one embodiment of the present application, the imaging system satisfies: 7.5< (D5 m + D5 m)/(T56-CP 5+ CT 5) <25.5, wherein D5m is an outer diameter of an image-side surface of the fifth spacing element, D5m is an inner diameter of the image-side surface of the fifth lens, T56 is an air gap between the fifth lens and the sixth lens along the optical axis, CP5 is a maximum thickness of the fifth spacing element, and CT5 is a center thickness of the fifth lens.
In one embodiment of the present application, the imaging system satisfies: 4.0< | f/R9 | (D5 m/EP 45) | <22.5, where f is the total effective focal length of the imaging system, R9 is the radius of curvature of the object-side face of the fifth lens, D5m is the outer diameter of the image-side face of the fifth spacing element, and EP45 is the distance along the optical axis between the image-side face of the fourth spacing element and the object-side face of the fifth spacing element.
In one embodiment of the present application, the imaging system satisfies: 0.5mm -1 <(TD*tan(Semi-FOV)/(∑CP*D5s)<14.0mm -1 And TD is the distance from the object side surface of the first lens to the image side surface of the sixth lens along the optical axis, semi-FOV is the maximum half field angle of the imaging system, Σ CP is the sum of the maximum thicknesses of the first to fifth spacing elements, and D5s is the outer diameter of the object side surface of the fifth spacing element.
The imaging system comprises a lens group, a plurality of spacing elements and a lens barrel for accommodating the lens group and the spacing elements, and performance indexes such as relative illumination, distortion and the like of the imaging system are controlled within a reasonable range by controlling the focal power of a first lens, a second lens and a third lens; meanwhile, the spacing elements are reasonably arranged among the lenses, so that redundant light rays can be effectively blocked, parasitic light is reduced, and the assembly stability of the imaging system is improved. Furthermore, the size of the imaging system in the optical axis direction can be controlled by reasonably controlling the addition relation between the ratio of the total effective focal length of the imaging system and the distance from the object side surface of the first lens to the image side surface of the sixth lens along the optical axis, and the ratio of the size of the lens barrel in the optical axis direction to the sum of the maximum thicknesses of the first spacing element to the fifth spacing element, so that the miniaturization of the imaging system is realized.
Drawings
Other features, objects and advantages of the present application will become more apparent upon reading of the following detailed description of non-limiting embodiments thereof, with reference to the accompanying drawings, in which:
FIG. 1 shows a parametric annotation schematic of an imaging system according to the present application;
fig. 2 shows a schematic cross-sectional view of an imaging system according to embodiment 1 of the present application;
fig. 3 shows a schematic cross-sectional view of another imaging system according to embodiment 1 of the present application;
fig. 4 shows a schematic cross-sectional view of a further imaging system according to embodiment 1 of the present application;
fig. 5A to 5C show an on-axis chromatic aberration curve, an astigmatic curve, and a chromatic aberration of magnification curve, respectively, of an imaging system according to embodiment 1 of the present application;
fig. 6 shows a schematic cross-sectional view of an imaging system according to embodiment 2 of the present application;
fig. 7 shows a schematic cross-sectional view of another imaging system according to embodiment 2 of the present application;
fig. 8 shows a schematic cross-sectional view of yet another imaging system according to embodiment 2 of the present application;
fig. 9A to 9C show an on-axis chromatic aberration curve, an astigmatic curve, and a chromatic aberration of magnification curve, respectively, of an imaging system according to embodiment 2 of the present application;
fig. 10 shows a schematic cross-sectional view of an imaging system according to embodiment 3 of the present application;
fig. 11 shows a cross-sectional schematic view of another imaging system according to embodiment 3 of the present application;
fig. 12 shows a schematic cross-sectional view of a further imaging system according to embodiment 3 of the present application; and
fig. 13A to 13C show an on-axis chromatic aberration curve, an astigmatism curve, and a chromatic aberration of magnification curve, respectively, of an imaging system according to embodiment 3 of the present application.
Detailed Description
For a better understanding of the present application, various aspects of the present application will be described in more detail with reference to the accompanying drawings. It should be understood that the detailed description is merely illustrative of exemplary embodiments of the present application and does not limit the scope of the present application in any way. Like reference numerals refer to like elements throughout the specification. The expression "and/or" includes any and all combinations of one or more of the associated listed items.
In the drawings, the thickness, size, and shape of the lens have been slightly exaggerated for convenience of explanation. In particular, the shapes of the spherical or aspherical surfaces shown in the drawings are shown by way of example. That is, the shape of the spherical surface or the aspherical surface is not limited to the shape of the spherical surface or the aspherical surface shown in the drawings. The figures are purely diagrammatic and not drawn to scale.
Herein, the paraxial region refers to a region near the optical axis. If the lens surface is convex and the convex position is not defined, it means that the lens surface is convex at least in the paraxial region; if the lens surface is concave and the concave position is not defined, it means that the lens surface is concave at least in the paraxial region. The surface of each lens closest to the object is called the object side surface of the lens, and the surface of each lens closest to the imaging surface is called the image side surface of the lens.
It should be noted that in this specification, the expressions first, second, third, etc. are used only to distinguish one feature from another, and do not represent any limitation on the features. Thus, the first lens discussed below may also be referred to as the second lens or the third lens without departing from the teachings of the present application.
It will be further understood that the terms "comprises," "comprising," "has," "having," "includes" and/or "including," when used in this specification, specify the presence of stated features, elements, and/or components, but do not preclude the presence or addition of one or more other features, elements, components, and/or groups thereof. Moreover, when a statement such as "at least one of" appears after the list of listed features, that the entirety of the listed features is modified rather than modifying individual elements in the list. Furthermore, when describing embodiments of the present application, the use of "may" mean "one or more embodiments of the present application. Also, the term "exemplary" is intended to refer to an example or illustration.
Unless otherwise defined, all terms (including 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. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The following examples merely illustrate several embodiments of the present invention, which are described in more detail and detail, but are not to be construed as limiting the scope of the present invention. It should be noted that, for those skilled in the art, without departing from the concept of the present application, several variations and modifications may be made, which all fall within the protection scope of the present invention, for example, the lens group, the lens barrel and the spacing element in the embodiments of the present application may be combined arbitrarily, and the lens group in one embodiment is not limited to be combined with the lens barrel, the spacing element and the like in the embodiment. The present application will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.
The features, principles, and other aspects of the present application are described in detail below.
An imaging system according to an exemplary embodiment of the present application may include a lens group, a plurality of spacing elements, and a lens barrel for accommodating the lens group and the plurality of spacing elements, wherein the lens group includes, in order from an object side to an image side along an optical axis: the lens includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens.
In an exemplary embodiment, the first lens element can have a negative optical power, the object-side surface can be concave or convex, the image-side surface can be concave, the second lens element can have a positive optical power, the object-side surface can be convex, and the image-side surface can be convex; the third lens element has negative focal power, and has a concave object-side surface and a convex image-side surface; the fourth lens can have positive focal power or negative focal power, the object side surface of the fourth lens can be a convex surface or a concave surface, and the image side surface of the fourth lens can be a convex surface; the fifth lens element can have a positive power or a negative power and is a meniscus lens element, and specifically, the fifth lens element can have a convex object-side surface, a concave image-side surface, or a concave object-side surface and a convex image-side surface; the sixth lens element can have a positive or negative power, and can have a convex object-side surface and a concave image-side surface. The image pickup effect can be effectively improved by reasonably distributing the surface type and the focal power of each lens of the imaging system. In addition, the surface shape of each lens can be reasonably controlled, and the image resolution of the imaging system can be effectively improved and the aberration of the imaging system can be balanced by adjusting the path of light rays in the optical system. Specifically, by controlling the fifth lens to be a meniscus lens, the molding process of the lens can be facilitated. Specifically, by controlling the first lens and the third lens to have negative focal power and controlling the image side surface of the third lens to be a concave surface, the layout of light rays entering the third lens can be effectively improved.
In an exemplary embodiment, the plurality of spacer elements includes at least one spacer element positioned between any adjacent two lenses, the at least one spacer element being in contact with at least a portion of an adjacent lens. Specifically, the plurality of spacer elements includes, for example, a first spacer element between the first lens and the second lens, a second spacer element between the second lens and the third lens, a third spacer element between the third lens and the fourth lens, a fourth spacer element between the fourth lens and the fifth lens, and a fifth spacer element between the fifth lens and the sixth lens. Alternatively, the first spacer element may be in contact with an image-side surface portion of the first lens, the second spacer element may be in contact with an image-side surface portion of the second lens, the third spacer element may be in contact with an image-side surface portion of the third lens, the fourth spacer element may be in contact with an image-side surface portion of the fourth lens, and the fifth spacer element may be in contact with an image-side surface portion of the fifth lens. Optionally, a portion of any one of the first to fifth spacing elements in contact with the image side surface of an adjacent lens may include a non-effective optical portion (e.g., an edge region of the lens). By arranging the plurality of spacing elements and enabling the spacing elements to be in contact with the adjacent lens, the blocking of redundant reflection light paths is facilitated, the imaging cleanliness of an imaging system is improved, the generation of stray light and ghost images is reduced, and the imaging quality is improved; and can guarantee that a plurality of spacer elements assemble with lens cone, lens in order to guarantee the stability after the assembly.
In an exemplary embodiment, the outer diameter of the object side surface of the third spacer element is equal to the outer diameter of the image side surface, and the inner diameter of the object side surface of the third spacer element is equal to the inner diameter of the image side surface. The third spacing element arranged as above can have a relatively thin thickness, and in combination with the optimization of the light layout that the first lens and the third lens have negative focal power and the image side surface of the third lens is a concave surface, the third spacing element can effectively absorb marginal light rays passing through the third lens, so as to improve stray light.
In an exemplary embodiment, the plurality of spacer elements further comprises: a sixth spacing element in contact with the image side portion of the second spacing element. Through rationally setting up sixth interval component, can improve unnecessary light's absorption efficiency, and then improve the imaging quality. In addition, the contact between the sixth spacing element and the second spacing part is controlled, so that the electrostatic repulsion of the PC component in the assembling process can be reduced, the stability of the lens component in the assembling process is ensured, and the manufacturing yield of the lens is improved.
In an exemplary embodiment, with reference to the dimensioning of fig. 1, the imaging system satisfies: 5.0< (f/TD) + (L/. Sigma. CP) <52.0; wherein f is the total effective focal length of the imaging system, L is the dimension of the lens barrel along the optical axis, TD is the distance along the optical axis from the object side surface of the first lens to the image side surface of the sixth lens, and Σ CP is the sum of the maximum thicknesses of the spacing elements in the first spacing element to the fifth spacing element. Still further, the imaging system satisfies: 5.5< (f/TD) + (L/∑ CP) <51.5. By reasonably controlling the addition relation between the ratio of the total effective focal length of the imaging system and the distance from the object side surface of the first lens to the image side surface of the sixth lens along the optical axis, and the ratio of the size of the lens barrel along the optical axis direction to the sum of the maximum thicknesses of the spacing elements in the first spacing element to the fifth spacing element, the size of the imaging system in the optical axis direction can be controlled, and the miniaturization of the imaging system is realized.
It is understood that, in order to make the structure and the reference of the drawings clearer, the reference of the dimensions of each component in fig. 1 is simplified, the dimension reference of an individual spacing element is taken as an example only, and for similar dimension definitions of the remaining spacing elements, reference may be made to the exemplary reference, and the detailed description of the present application is omitted here.
In an exemplary embodiment, with reference to the dimensioning of fig. 1, the imaging system satisfies: -18.5< (f 3+ f 2)/(D3 s-D2 m) < -8.5, wherein f3 is the effective focal length of the third lens, f2 is the effective focal length of the second lens, D3s is the outer diameter of the object side face of the third spacer element, and D2m is the outer diameter of the image side face of the second spacer element. Still further, the imaging system satisfies: -18.0< (f 3+ f 2)/(D3 s-D2 m) < -9.0. By reasonably controlling the ratio relationship between the sum of the effective focal lengths of the second lens and the third lens and the difference between the outer diameter of the object side surface of the third spacing element and the outer diameter of the image side surface of the second spacing element, the relative illumination of the outer field of view of the imaging system can be controlled within a better range.
In an exemplary embodiment, with reference to the dimensioning of fig. 1, the imaging system satisfies: R3/R4<0, and R3/R6>0; wherein R3 is a radius of curvature of the object-side surface of the second lens element, R4 is a radius of curvature of the image-side surface of the second lens element, and R6 is a radius of curvature of the image-side surface of the third lens element. Still further, the imaging system satisfies: -2.5 yarn-woven R3/R4<0, and 0 yarn-woven R3/R6<3.0. The ratio of the curvature radius of the object side surface and the curvature radius of the image side surface of the second lens and the ratio of the curvature radius of the object side surface of the second lens and the curvature radius of the image side surface of the third lens are reasonably controlled, so that the second lens and the third lens have good capability of balancing axial chromatic aberration, and the optical imaging system can obtain good imaging quality within a certain imaging waveband bandwidth range.
In an exemplary embodiment, with reference to the dimensioning of fig. 1, the imaging system satisfies: f4/f5<0, wherein f4 is the focal power of the fourth lens, and f5 is the focal power of the fifth lens. Still further, the imaging system satisfies: -3.5 sj 4/f5<0. The fourth lens has good astigmatism balancing capability by reasonably controlling the ratio of the curvature radii of the object side surface and the image side surface of the fourth lens within a reasonable range.
In an exemplary embodiment, with reference to the dimensioning of fig. 1, the imaging system satisfies: 3.0 straw ct4/(CP 3+ CP 4) × N4<45.0, where CT4 is the central thickness of the fourth lens, CP3 is the maximum thickness of the third spacer element, CP4 is the maximum thickness of the fourth spacer element, and N4 is the refractive index of the fourth lens. Still further, the imaging system satisfies: 3.5 lin ct4/(CP 3+ CP 4) × N4<44.5. By controlling the product relationship between the ratio of the central thickness of the fourth lens to the sum of the maximum thicknesses of the third spacing element and the fourth spacing element and the refractive index of the fourth lens within a certain range, the edge thicknesses of the lens and the spacing elements can be effectively controlled, the limit process during lens production is improved, the assembly stability of the imaging system is improved, the overall length of the imaging system can be controlled, and the imaging system is facilitated to be miniaturized.
In an exemplary embodiment, with reference to the dimensioning of fig. 1, the imaging system satisfies: -7.4< (d 2bs-d2 bm)/T23 + f2/CT2<5.5, wherein d2bm is the inner diameter of the image side surface of the sixth spacing element, d2bs is the inner diameter of the object side surface of the sixth spacing element, T23 is the air gap between the second lens and the third lens along the optical axis, f2 is the effective focal length of the second lens, and CT2 is the center thickness of the second lens. Still further, the imaging system satisfies: -7.0< (d 2bs-d2 bm)/T23 + f2/CT2<5.0. By reasonably setting the addition relation between the difference of the inner diameters of the image side surface and the outer side surface of the sixth spacing element and the ratio of the air gap between the second lens and the third lens along the optical axis and the ratio of the effective focal length of the second lens and the center thickness of the second lens, the redundant light rays can be effectively blocked, ghost image stray light is improved, aberration is corrected, and imaging quality can be improved.
In an exemplary embodiment, with reference to the dimensioning of fig. 1, the imaging system satisfies: l (CT 2-EP 12)/(T23-CP 2) | <10.0, where CT2 is the center thickness of the second lens, EP12 is the distance along the optical axis between the image-side surface of the first spacer element and the object-side surface of the second spacer element, T23 is the air gap along the optical axis between the second lens and the third lens, and CP2 is the maximum thickness of the second spacer element. Still further, the imaging system satisfies: [ CT2-EP 12)/(T23-CP 2 ] <9.5 ]. Satisfy above-mentioned conditional expression, the thickness that can effectively retrain second lens and second interval component is at certain extent and control the interval between second lens and the first lens to can guarantee the compactedness between two lenses, satisfy machine-shaping and shorten lens thickness, be favorable to imaging system's miniaturization.
In an exemplary embodiment, with reference to the dimensioning of fig. 1, the imaging system satisfies: -16.5< (D1 m-D1 s)/(CT 1-T12-CP 1) < -0.5, wherein D1m is the outer diameter of the image side face of the first spacer element, D1s is the inner diameter of the object side face of the first spacer element, CT1 is the center thickness of the first lens, T12 is the air gap between the first lens and the second lens along the optical axis, and CP1 is the maximum thickness of the first spacer element. Still further, the imaging system satisfies: -16.0< (D1 m-D1 s)/(CT 1-T12-CP 1) < -1.0. By controlling the conditional expression, the inner diameter of the object side surface and the outer diameter of the image side surface of the first spacing element, the maximum thickness of the first spacing element, the center thickness of the first lens and the air gap between the first lens and the second lens can be effectively restrained, so that the redundant light passing through the first lens can be effectively blocked, the system chromatic aberration can be reduced, and the imaging quality can be comprehensively improved.
In an exemplary embodiment, with reference to the dimensioning of fig. 1, the imaging system satisfies: 2.5< (D2 s/D2 m) + (R3/CT 2) <7.0, wherein D2s is the outer diameter of the object-side face of the second spacer element, D2m is the inner diameter of the image-side face of the second spacer element, R3 is the radius of curvature of the object-side face of the second lens, CT2 is the central thickness of the second lens. Still further, the imaging system satisfies: 3.0< (D2 s/D2 m) + (R3/CT 2) <6.5. Through controlling this conditional expression, can rationally set up the internal diameter of second spacer element and the shape of external diameter and second lens, can effectively reduce the bending of lens, reduce shaping risk and outward appearance risk, promote stability, avoided the relatively poor problem of wide angle imaging system's general uniformity to a certain extent.
In an exemplary embodiment, with reference to the dimensioning of fig. 1, the imaging system satisfies: 0< (T23 + T34)/(CP 1+ CP 2) <10.0, where T23 is an air gap along the optical axis between the second lens and the third lens, T34 is an air gap along the optical axis between the third lens and the fourth lens, CP1 is a maximum thickness of the first spacer element, and CP2 is a maximum thickness of the second spacer element. Still further, the imaging system satisfies: 0< (T23 + T34)/(CP 1+ CP 2) <9.0. By controlling the conditional expression, the maximum thickness of the first spacing element and the second spacing element, the air gap between the second lens and the third lens along the optical axis and the air gap between the third lens and the fourth lens along the optical axis can be effectively restrained, so that the internal space of the imaging system can be reasonably distributed, the air gap between the lenses can be stabilized, the sensitivity of the imaging system can be reduced, and the reliability can be improved.
In an exemplary embodiment, with reference to the dimensioning of fig. 1, the imaging system satisfies: 9.5< (CT 4+ EP 23)/(EP 34-CT 3) <17.4, wherein CT4 is a central thickness of the fourth lens, EP23 is a distance along the optical axis between an image-side surface of the second spacer element and an object-side surface of the third spacer element, CT3 is a central thickness of the third lens, and EP34 is a distance along the optical axis between an image-side surface of the third spacer element and an object-side surface of the fourth spacer element. Still further, the imaging system satisfies: 10.0< (CT 4+ EP 23)/(EP 34-CT 3) <17.0. By controlling the conditional expression, the central thickness of the third lens, the central thickness of the fourth lens and the interval between the spacing elements can be restrained, so that the compactness among the lenses is improved, the internal space of the imaging system is reasonably distributed, and the MTF yield of the imaging system is improved.
In an exemplary embodiment, with reference to the dimensioning of fig. 1, the imaging system satisfies: -41.5mm -1 <(d4m-d4s+D4s)/(R8*T45)<-9.0mm -1 Wherein D4m is an inner diameter of an image-side surface of the fourth spacer, D4s is an inner diameter of an object-side surface of the fourth lens element, D4s is an outer diameter of the object-side surface of the fourth spacer, R8 is a radius of curvature of the image-side surface of the fourth lens element, and T45 is an air gap between the fourth lens element and the fifth lens element along the optical axis. Still further, the imaging system satisfies: -41.0mm -1 <(d4m-d4s+D4s)/(R8*T45)<-9.5mm -1 . By controlling the conditional expression, the inner diameter and the outer diameter of the object side surface of the fourth spacing element, the inner diameter of the image side surface, the curvature of the image side surface of the fourth lens, and the air gap between the fourth lens and the fifth lens along the optical axis can be reasonably set, so that the fourth spacing element and the fourth lens structure part can be tightly supported, the assembly precision is ensured, and the parasitic light risk is effectively avoided through the fourth spacing element.
In an exemplary embodiment, with reference to the dimensioning of fig. 1, the imaging system satisfies: 0< (R10 + R11) > FNO/(D5 s-D4 m) <8.0, where R10 is the radius of curvature of the image-side surface of the fifth lens, R11 is the radius of curvature of the object-side surface of the sixth lens, FNO is the aperture value of the imaging system, D5s is the outer diameter of the object-side surface of the fifth spacing element, and D4m is the outer diameter of the image-side surface of the fourth spacing element. Still further, the imaging system satisfies: 0< (R10 + R11) > FNO/(D5 s-D4 m) <7.5. By controlling the conditional expression, the shapes of the fifth lens and the sixth lens can be effectively controlled, so that the convergence degree of the entering light rays is controlled, and ghost images and distortion of an imaging system are improved; in addition, the outer diameter of the object side surface of the fifth spacing element, the outer diameter of the image side surface of the fourth spacing element and the aperture value of the imaging system are controlled within a certain range, so that the wide-angle performance and the deep long-range view of the imaging system are kept, meanwhile, the matching performance of the spacing elements and the lens barrel is controlled, the assembly stability is improved, and the imaging quality is improved.
In an exemplary embodiment, with reference to the dimensioning of fig. 1, the imaging system satisfies: 7.5< (D5 m + D5 m)/(T56-CP 5+ CT 5) <25.5, wherein D5m is the outer diameter of the image-side surface of the fifth spacing element, D5m is the inner diameter of the image-side surface of the fifth lens, T56 is the air gap between the fifth lens and the sixth lens along the optical axis, CP5 is the maximum thickness of the fifth spacing element, and CT5 is the center thickness of the fifth lens. Still further, the imaging system satisfies: 8.0< (D5 m + D5 m)/(T56-CP 5+ CT 5) <25.0. By reasonably setting the inner diameter, the outer diameter and the maximum thickness of the image side surface of the fifth spacing element, the matching degree of the spacing element and the subsequent lens is high, the stability among the lenses is enhanced, and the reliability is improved; in addition, the center thickness of the fifth lens and the air gap between the fifth lens and the sixth lens along the optical axis are controlled within a certain range, so that the aberration of an imaging system can be corrected, and a better angle of view can be obtained.
In one embodiment of the present application, an imaging system satisfies: 4.0< | f/R9 | <22.5 (D5 m/EP 45) | <22.5, where f is the total effective focal length of the imaging system, R9 is the radius of curvature of the object-side face of the fifth lens, D5m is the outer diameter of the image-side face of the fifth spacing element, and EP45 is the distance along the optical axis between the image-side face of the fourth spacing element and the object-side face of the fifth spacing element. Still further, the imaging system satisfies: 4.5< | f/R9 (D5 m/EP 45) | <22.0. The characteristic of large market angle of the imaging system is ensured by controlling the ratio of the total effective focal length of the imaging system to the curvature radius of the object side surface of the fifth lens, the central thickness of the fifth lens can be further controlled by restricting the ratio of the outer diameter of the image side surface of the fifth spacing element to the ratio of the image side surface of the fourth spacing element to the object side surface of the fifth spacing element, the processing difficulty of the lens and the spacing element is reduced, and the cost is reduced.
In an exemplary embodiment, with reference to the dimensioning of fig. 1, the imaging system satisfies: 0.5mm -1 <(TD*tan(Semi-FOV)/(∑CP*D5s)<14.0mm -1 Where TD is a distance along the optical axis from the object-side surface of the first lens to the image-side surface of the sixth lens, semi-FOV is a maximum half field angle of the imaging system, Σ CP is a sum of maximum thicknesses of the respective first to fifth spacing elements, and D5s is an outer diameter of the object-side surface of the fifth spacing element. Still further, the imaging system satisfies: 1.0mm -1 <(TD*tan(Semi-FOV)/(∑CP*D5s)<13.5mm -1 . By controlling the conditional expression, the axial lengths of the lens group and the spacing element can be reasonably set, and the reasonable arrangement of the central thicknesses of the lenses is favorable for forming a large field angle; through the effective cooperation of lens and spacer element and the external diameter of the object side face that rationally sets up fifth spacer element, not only effectively shortened the height of lens cone, the size of the image side end of effective control lens cone moreover is favorable to the miniaturized characteristics of imaging system.
In an exemplary embodiment, the fourth lens is made of glass, and any one of the first to third lenses and the fifth and sixth lenses is made of plastic. The fourth lens is made of glass materials, so that the fourth lens has a high Abbe number and a high refractive index, and the size of the lens group can be reduced; any one of the first lens, the third lens, the fifth lens and the sixth lens is made of plastic, so that the cost of the lens group is saved, the cost of an imaging system is reduced, and the processing difficulty of the lenses is reduced while high imaging quality is obtained. In an exemplary embodiment, a lens group according to the present application may further include a filter for correcting color deviation and/or a protective glass for protecting a photosensitive element located on an image forming surface.
In the embodiment of the present application, at least one of the mirror surfaces of each of the first to sixth lenses is an aspherical mirror surface. The aspheric lens is characterized in that: the curvature varies continuously from the center of the lens to the periphery of the lens. Unlike a spherical lens having a constant curvature from the center of the lens to the periphery of the lens, an aspherical lens has better curvature radius characteristics, and has advantages of improving distortion aberration and improving astigmatic aberration. After the aspheric lens is adopted, the aberration generated in imaging can be eliminated as much as possible, and the imaging quality is further improved. Optionally, the object-side surface and the image-side surface of each of the first to sixth lenses are aspheric mirror surfaces.
However, it will be appreciated by those skilled in the art that the number of lenses making up the imaging system can be varied to achieve the various results and advantages described in this specification without departing from the claimed subject matter. For example, although six lenses are exemplified in the embodiment, the imaging system is not limited to including six lenses. The imaging system may also include other numbers of lenses, if desired.
Specific examples of imaging systems that can be adapted to the above-described embodiments are further described below with reference to the accompanying drawings.
Example 1
An imaging system according to embodiment 1 of the present application is described below with reference to fig. 2 to 5C. Fig. 2 to 4 respectively show schematic cross-sectional views of an imaging system 110, an imaging system 120, and an imaging system 130 according to embodiment 1 of the present application.
As shown in fig. 2 to fig. 4, the imaging system 110, the imaging system 120, and the imaging system 130 respectively include lens groups, and the lens groups include, in order from an object side to an image side along an optical axis: a first lens E1, a stop STO, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a filter E7, and an image forming surface S15.
The first lens element E1 has a negative refractive power, and has a concave object-side surface S1 and a concave image-side surface S2. The second lens element E2 has positive power, and has a convex object-side surface S3 and a convex image-side surface S4. The third lens element E3 has a negative refractive power, and has a concave object-side surface S5 and a concave image-side surface S6. The fourth lens element E4 has positive power, and has a convex object-side surface S7 and a convex image-side surface S8. The fifth lens element E5 has a negative power, and has a convex object-side surface S9 and a concave image-side surface S10, and the sixth lens element E6 has a negative power, and has a convex object-side surface S11 and a concave image-side surface S12. The filter E7 has an object side surface S13 and an image side surface S14. The light from the object sequentially passes through the respective surfaces S1 to S14 and is finally imaged on the imaging surface S15.
Table 1 shows a basic parameter table of the imaging system of example 1, in which the units of the radius of curvature, the thickness/distance, and the focal length are all millimeters (mm).
Figure BDA0003748898050000111
TABLE 1
In the present embodiment, the total effective focal length f of the imaging system is 2.27mm, the distance TTL on the optical axis from the object-side surface S1 to the imaging surface S15 of the first lens E1 is 4.89mm, the maximum half field angle Semi-FOV of the imaging system is 53.52 °, and the aperture value FNO of the imaging system is 2.22.
In the present embodiment, the face shape x of the aspheric surfaces included in the object-side surface and the image-side surface of the lenses of the first lens E1 to the sixth lens E6 can be defined using, but not limited to, the following aspheric surface formula:
Figure BDA0003748898050000112
wherein x is the rise of the distance from the aspheric surface vertex to the aspheric surface vertex when the aspheric surface is at the position with the height of h along the optical axis direction; c is the paraxial curvature of the aspheric surface, c =1/R (i.e., paraxial curvature c is the inverse of radius of curvature R in table 1 above); k is a conic coefficient; ai is the correction coefficient of the i-th order of the aspheric surface. Table 2 below gives the high-order term coefficients A4, A6, A8, a10, a12, a14, a16, a18, a20, a22, a24, a26, a28, and a30 that can be used for each of the aspherical mirrors S1 to S12 in example 1.
Figure BDA0003748898050000113
Figure BDA0003748898050000121
TABLE 2
As shown in fig. 2 to 4, the imaging system 110, the imaging system 120, and the imaging system 130 further include a plurality of spacing elements and a lens barrel P0 for accommodating the lens group and the plurality of spacing elements, respectively. The plurality of spacer elements includes, for example, spacer elements P1 to P5. Alternatively, P1 to P5, and a lens barrel P0 for accommodating the lens groups and the spacer members P1 to P5. The first spacing element P1 is located between the first lens E1 and the second lens E2, and the first spacing element P1 is in partial contact with the image side surface S2 of the first lens E1; the second spacing element P2 is positioned between the first lens E2 and the second lens E3, and the second spacing element P2 is in partial contact with the image side surface S4 of the second lens E2; the third spacing element P3 is positioned between the third lens E3 and the fourth lens E4, and the third spacing element P3 and the image-side surface S6 of the third lens E3 are partially in contact; the fourth spacing element P4 is located between the fourth lens E4 and the fifth lens E5, and the fourth spacing element P4 is in partial contact with the image side surface S8 of the fourth lens E4; the fifth spacing element P5 is located between the fifth lens E5 and the sixth lens E6, and the fifth spacing element P5 and the image-side surface S10 of the fifth lens E5 are partially in contact.
Illustratively, the plurality of spacer elements further includes, for example, a sixth spacer element P2b between the second spacer element P2 and the third lens E3 and a seventh spacer element P4b between the fourth spacer element P4 and the fifth lens E5. As an option, the sixth spacing element P2b may be in partial contact with the second spacing element P2 and the third lens E3, respectively, and the seventh spacing element P4b may be in partial contact with the fourth spacing element P4 and the fifth lens E5, respectively.
In each of the imaging systems as shown in fig. 2 to 4, the first to sixth spacing elements P1 to P2b may block the entry of external unwanted light, make the lens and the lens barrel better supported, and enhance the structural stability of the imaging system.
Table 3 shows a basic parameter table of the lens barrel and the spacer element of the three imaging systems of embodiment 1, and the unit of each parameter in table 3 is millimeter (mm).
Figure BDA0003748898050000122
Figure BDA0003748898050000131
TABLE 3
Fig. 5A shows an on-axis chromatic aberration curve of the imaging system of embodiment 1, which represents the convergent focus deviations of light rays of different wavelengths after passing through the imaging system. Fig. 5B shows an astigmatism curve representing a meridional field curvature and a sagittal field curvature of the imaging system of embodiment 1. Fig. 5C shows a chromatic aberration of magnification curve of the imaging system of embodiment 1, which represents a deviation of different image heights on the imaging plane after the light passes through the lens. As can be seen from fig. 5A to 5C, the imaging system according to embodiment 1 can achieve good imaging quality.
Example 2
An imaging system according to embodiment 2 of the present application is described below with reference to fig. 6 to 9C. Fig. 6 to 8 respectively show schematic cross-sectional views of an imaging system 210, an imaging system 220, and an imaging system 230 according to embodiment 2 of the present application.
As shown in fig. 6 to 8, each of the imaging system 210, the imaging system 220, and the imaging system 230 includes a lens group, and the lens group includes, in order from an object side to an image side along an optical axis: a first lens E1, a stop STO, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a filter E7, and an image forming surface S15.
The first lens element E1 has a negative refractive power, and has a concave object-side surface S1 and a concave image-side surface S2. The second lens element E2 has positive power, and has a convex object-side surface S3 and a convex image-side surface S4. The third lens element E3 has a negative refractive power, and has a concave object-side surface S5 and a concave image-side surface S6. The fourth lens element E4 has a negative power, and has a concave object-side surface S7 and a convex image-side surface S8. The fifth lens element E5 has positive power, the object-side surface S9 is convex, the image-side surface S10 is concave, the sixth lens element E6 has negative power, the object-side surface S11 is convex, and the image-side surface S12 is concave. The filter E7 has an object side surface S13 and an image side surface S14. The light from the object sequentially passes through the respective surfaces S1 to S14 and is finally imaged on the imaging surface S15.
Table 4 shows a basic parameter table of the imaging system of example 2 in which the units of the radius of curvature, thickness/distance, and focal length are millimeters (mm).
Figure BDA0003748898050000132
Figure BDA0003748898050000141
TABLE 4
In the present embodiment, the total effective focal length f of the imaging system is 2.17mm, the distance TTL on the optical axis from the object-side surface S1 to the imaging surface S15 of the first lens E1 is 4.97mm, the maximum half field angle Semi-FOV of the imaging system is 53.53 °, and the aperture value FNO of the imaging system is 2.22.
Table 5 shows the high-order term coefficients A4, A6, A8, a10, a12, a14, a16, a18, a20, a22, a24, a26, a28, and a30 that can be used for each of the mirror surfaces in the aspherical surfaces S1 to S12 in example 2, wherein each of the aspherical surface types can be defined by the formula (1) given in example 1 above.
Flour mark A4 A6 A8 A10 A12 A14 A16
S1 2.63E-01 -4.42E-01 6.39E-01 -7.25E-01 5.59E-01 -2.49E-01 4.77E-02
S2 3.57E-01 -3.23E-01 3.51E-01 -6.60E-01 2.20E+00 -3.26E+00 1.69E+00
S3 1.15E-02 9.52E-03 -1.34E+00 6.97E+00 -1.98E+01 2.68E+01 -1.55E+01
S4 -3.51E-01 2.13E-01 -1.39E-01 -4.89E-01 8.20E-01 -5.38E-01 -5.86E-02
S5 -7.56E-02 -3.90E-01 4.09E-01 -2.08E-04 -8.18E-01 1.18E+00 -3.67E-01
S6 -1.31E-01 2.37E-01 -7.79E-01 1.70E+00 -2.10E+00 1.48E+00 -3.89E-01
S7 -2.28E-02 7.53E-02 4.39E-01 -2.21E+00 5.16E+00 -7.10E+00 5.73E+00
S8 -2.84E-01 8.53E-01 -1.94E+00 3.32E+00 -4.32E+00 4.26E+00 -2.90E+00
S9 -2.96E-01 6.59E-01 -1.37E+00 1.51E+00 -9.37E-01 3.24E-01 -5.88E-02
S10 -1.13E-01 2.30E-01 -4.48E-01 4.49E-01 -2.42E-01 6.77E-02 -7.73E-03
S11 -2.16E-01 -2.96E-01 7.66E-01 -7.68E-01 3.90E-01 -9.66E-02 9.33E-03
S12 -3.41E-01 2.71E-01 -1.34E-01 3.13E-02 -5.00E-04 -1.25E-03 1.79E-04
Flour mark A18 A20 A22 A24 A26 A28 A30
S1 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00
S2 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00
S3 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00
S4 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00
S5 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00
S6 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00
S7 -2.51E+00 4.60E-01 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00
S8 1.15E+00 -1.92E-01 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00
S9 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00
S10 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00
S11 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00
S12 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00
TABLE 5
As shown in fig. 6 to 8, the imaging system 210, the imaging system 220, and the imaging system 230 further include a plurality of spacing elements, and a lens barrel P0 for accommodating the lens group and the plurality of spacing elements, respectively. The plurality of spacer elements includes, for example, spacer elements P1 to P5. Optionally, the first spacing element P1 is located between the first lens E1 and the second lens E2, and the first spacing element P1 is in partial contact with the image side surface S2 of the first lens E1; the second spacing element P2 is positioned between the first lens E2 and the second lens E3, and the second spacing element P2 is in partial contact with the image side surface S4 of the second lens E2; the third spacing element P3 is positioned between the third lens E3 and the fourth lens E4, and the third spacing element P3 is partially in contact with the image side surface S6 of the third lens E3; the fourth spacing element P4 is located between the fourth lens E4 and the fifth lens E5, and the fourth spacing element P4 is in partial contact with the image side surface S8 of the fourth lens E4; the fifth spacing element P5 is located between the fifth lens E5 and the sixth lens E6, and the fifth spacing element P5 is in partial contact with the image side surface S10 of the fifth lens E5.
In the imaging system 220 as shown in fig. 7, the plurality of spacing elements further includes, for example, a sixth spacing element P2b between the second spacing element P2 and the third lens E3. As an option, the sixth spacing element P2b may be in partial contact with the second spacing element P2 and the third lens E3, respectively.
In the imaging system 230 as shown in fig. 8, the plurality of spacer elements further includes, for example, a sixth spacer element P2b between the second spacer element P2 and the third lens E3. As an option, the sixth spacing element P2b may be in partial contact with the second spacing element P2 and the third lens E3, respectively. The imaging system shown in fig. 6 to 8 includes a plurality of spacing elements to block the entry of external unwanted light, to make the lens and the lens barrel better supported, and to enhance the structural stability of the imaging system.
Table 6 shows a basic parameter table of the lens barrel and the spacer of three imaging systems of embodiment 2, and the unit of each parameter in table 6 is millimeter (mm).
System number/parameter d1s D1m d2m D2s D2m D3s d4s d4m D4s D4m d5m D5s D5m
210 2.134 3.154 2.664 3.307 3.354 3.686 2.436 2.503 3.675 3.654 3.041 4.524 4.524
220 2.134 3.154 1.744 3.486 3.486 3.686 2.436 2.503 3.675 3.654 3.041 4.524 4.524
230 2.134 3.154 1.866 3.307 3.394 3.686 2.436 2.503 3.956 3.935 2.961 4.524 4.524
System number/parameter d2bs d2bm CP1 EP12 CP2 EP23 CP3 EP34 CP4 EP45 CP5 L ∑CP
210 0.000 0.000 0.279 0.471 0.281 0.557 0.018 0.328 0.229 0.701 0.018 4.528 0.825
220 2.136 2.664 0.279 0.471 0.018 0.821 0.018 0.328 0.229 0.701 0.018 4.528 0.562
230 1.744 1.744 0.279 0.471 0.263 0.575 0.018 0.328 0.229 0.701 0.018 4.528 0.807
TABLE 6
Fig. 9A shows an on-axis chromatic aberration curve of the imaging system of embodiment 2, which represents the convergent focus deviations of light rays of different wavelengths after passing through the imaging system. Fig. 9B shows an astigmatism curve representing meridional field curvature and sagittal field curvature of the imaging system of embodiment 2. Fig. 9C shows a chromatic aberration of magnification curve of the imaging system of embodiment 2, which represents the deviation of different image heights on the imaging plane after the light passes through the lens. As can be seen from fig. 9A to 9C, the imaging system according to embodiment 2 can achieve good imaging quality.
Example 3
An imaging system according to embodiment 3 of the present application is described below with reference to fig. 10 to 13C. Fig. 10 to 12 respectively show schematic sectional views of an imaging system 310, an imaging system 320, and an imaging system 330 according to embodiment 3 of the present application.
As shown in fig. 10 to 12, each of the imaging system 310, the imaging system 320, and the imaging system 330 includes a lens group, and the lens group includes, in order from an object side to an image side along an optical axis: a first lens E1, a stop STO, a second lens E2, a third lens E3, a fourth lens E4, a fifth lens E5, a sixth lens E6, a filter E7, and an image forming surface S15.
The first lens element E1 has negative power, and has a convex object-side surface S1 and a concave image-side surface S2. The second lens element E2 has positive power, and has a convex object-side surface S3 and a convex image-side surface S4. The third lens element E3 has negative power, and has a convex object-side surface S5 and a concave image-side surface S6. The fourth lens element E4 has positive power, and has a convex object-side surface S7 and a convex image-side surface S8. The fifth lens element E5 has negative power, the object-side surface S9 is concave, the image-side surface S10 is convex, the sixth lens element E6 has negative power, the object-side surface S11 is convex, and the image-side surface S12 is concave. The filter E7 has an object side surface S13 and an image side surface S14. The light from the object passes through the respective surfaces S1 to S14 in order and is finally imaged on the imaging plane S15.
Table 7 shows a basic parameter table of the imaging system of example 3 in which the units of the radius of curvature, thickness/distance, and focal length are millimeters (mm).
Figure BDA0003748898050000161
TABLE 7
In the present embodiment, the total effective focal length f of the imaging system is 2.28mm, the distance TTL on the optical axis from the object-side surface S1 to the imaging surface S15 of the first lens E1 is 4.97mm, the maximum half field angle Semi-FOV of the imaging system is 54.85 °, and the aperture value FNO of the imaging system is 2.22.
Table 8 shows the high-order term coefficients A4, A6, A8, a10, a12, a14, a16, a18, a20, a22, a24, a26, a28, and a30 that can be used for each of the mirror surfaces in the aspherical surfaces S1 to S12 in example 3, wherein each of the aspherical surface types can be defined by the formula (1) given in example 1 above.
Figure BDA0003748898050000162
Figure BDA0003748898050000171
TABLE 8
As shown in fig. 10 to 12, the imaging system 310, the imaging system 320, and the imaging system 330 each further include a plurality of spacing elements, and a lens barrel P0 for accommodating the lens group and the plurality of spacing elements. The plurality of spacer elements includes, for example, spacer elements P1 to P5. Optionally, the first spacing element P1 is located between the first lens E1 and the second lens E2, and the first spacing element P1 is in partial contact with the image side surface S2 of the first lens E1; the second spacing element P2 is positioned between the first lens E2 and the second lens E3, and the second spacing element P2 is in partial contact with the image side surface S4 of the second lens E2; the third spacing element P3 is positioned between the third lens E3 and the fourth lens E4, and the third spacing element P3 is partially in contact with the image side surface S6 of the third lens E3; the fourth spacing element P4 is located between the fourth lens E4 and the fifth lens E5, and the fourth spacing element P4 is in partial contact with the image-side surface S8 of the fourth lens E4; the fifth spacing element P5 is located between the fifth lens E5 and the sixth lens E6, and the fifth spacing element P5 is in partial contact with the image side surface S10 of the fifth lens E5.
Illustratively, the plurality of spacing elements further includes, for example, a sixth spacing element P2b located between the second spacing element P2 and the third lens E3. As an option, the sixth spacing element P2b may be in partial contact with the second spacing element P2 and the third lens E3, respectively. In the imaging system as shown in fig. 10 to 12, the first to sixth spacing elements P1 to P2b may block the entry of external unwanted light, make the lens and the lens barrel better bear, and enhance the structural stability of the imaging system.
Table 9 shows a basic parameter table of the lens barrel and the spacer element of the three imaging systems of embodiment 3, and the unit of each parameter in table 9 is millimeter (mm).
Figure BDA0003748898050000172
Figure BDA0003748898050000181
TABLE 9
Fig. 13A shows an on-axis chromatic aberration curve of the imaging system of embodiment 3, which represents the convergent focus deviations of light rays of different wavelengths after passing through the imaging system. Fig. 13B shows an astigmatism curve representing meridional field curvature and sagittal field curvature of the imaging system of embodiment 3. Fig. 13C shows a chromatic aberration of magnification curve of the imaging system of embodiment 3, which represents a deviation of different image heights on the imaging plane after the light passes through the lens. As can be seen from fig. 13A to 13C, the imaging system according to embodiment 3 can achieve good imaging quality.
In summary, the relationship shown in table 10 is satisfied in each of embodiments 1 to 3, wherein the system numbers of the respective image forming systems in embodiments 1 to 3 are given in table 10.
Figure BDA0003748898050000182
TABLE 10
The above description is only a preferred embodiment of the application and is illustrative of the principles of the technology employed. It will be appreciated by a person skilled in the art that the scope of protection covered by the present application is not limited to the embodiments with a specific combination of the features described above, but also covers other embodiments with any combination of the features described above or their equivalents without departing from the scope of the present application. For example, the above features may be replaced with (but not limited to) features having similar functions disclosed in the present application.

Claims (20)

1. Imaging system comprising a lens group, a plurality of spacing elements and a lens barrel for accommodating the lens group and the plurality of spacing elements,
the lens group comprises the following components in order from an object side to an image side along an optical axis: the lens group comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a sixth lens, wherein the number of the lenses with focal power in the lens group is six, and the first lens has negative focal power; the second lens has a positive optical power, and the third lens has a negative optical power;
the plurality of spacing elements comprises:
a first spacer element in contact with an image side surface portion of the first lens;
a second spacer element in contact with an image-side surface portion of the second lens;
a third spacer element in contact with an image-side surface portion of the third lens;
a fourth spacer element in contact with an image-side surface portion of the fourth lens; and
a fifth spacer element in contact with an image-side surface portion of the fifth lens;
wherein an outer diameter of an object side end of the lens barrel is smaller than an outer diameter of an image side end thereof, and the imaging system satisfies:
5.0<(f/TD)+(L/∑CP)<52.0，
f is the total effective focal length of the imaging system, L is the size of the lens barrel along the optical axis direction, TD is the distance from the object side surface of the first lens to the image side surface of the sixth lens along the optical axis, and Σ CP is the sum of the maximum thicknesses of the first spacing element to the fifth spacing element.
2. The imaging system of claim 1, wherein the imaging system satisfies:
R3/R4<0, and R3/R6>0;
wherein R3 is a radius of curvature of an object-side surface of the second lens element, R4 is a radius of curvature of an image-side surface of the second lens element, and R6 is a radius of curvature of an image-side surface of the third lens element.
3. The imaging system of claim 1, wherein the imaging system satisfies:
f4/f5<0，
wherein f4 is the focal power of the fourth lens, and f5 is the focal power of the fifth lens.
4. The imaging system of claim 1, wherein the fifth lens is a meniscus lens.
5. The imaging system of claim 3, wherein the fourth lens is made of glass.
6. The imaging system of claim 1, wherein the imaging system satisfies:
-18.5<(f3+f2)/(D3s-D2m)<-8.5，
wherein f3 is an effective focal length of the third lens element, f2 is an effective focal length of the second lens element, D3s is an outer diameter of an object-side surface of the third spacer element, and D2m is an outer diameter of an image-side surface of the second spacer element.
7. The imaging system of claim 1, wherein an outer diameter of the object side surface of the third spacer element is equal to an outer diameter of the image side surface, and an inner diameter of the object side surface of the third spacer element is equal to an inner diameter of the image side surface.
8. The imaging system of claim 1, wherein the plurality of spacing elements further comprises:
a sixth spacer element in contact with the image side portion of the second spacer element.
9. The imaging system of any of claims 1 to 8, wherein the imaging system satisfies:
3.0<CT4/(CP3+CP4)*N4<45.0，
wherein CT4 is a center thickness of the fourth lens, CP3 is a maximum thickness of the third spacer element, CP4 is a maximum thickness of the fourth spacer element, and N4 is a refractive index of the fourth lens.
10. The imaging system of claim 8, wherein the imaging system satisfies:
-7.4<(d2bs-d2bm)/T23+f2/CT2<5.5，
wherein d2bm is an inner diameter of an image side surface of the sixth spacing element, d2bs is an inner diameter of an object side surface of the sixth spacing element, T23 is an air gap between the second lens and the third lens along the optical axis, f2 is an effective focal length of the second lens, and CT2 is a central thickness of the second lens.
11. The imaging system of any of claims 1 to 8, wherein the imaging system satisfies:
|(CT2-EP12)/(T23-CP2)|<10.0，
wherein CT2 is a center thickness of the second lens, EP12 is a distance between an image-side surface of the first spacer element and an object-side surface of the second spacer element along the optical axis, T23 is an air gap between the second lens and the third lens along the optical axis, and CP2 is a maximum thickness of the second spacer element.
12. The imaging system of any of claims 1 to 8, wherein the imaging system satisfies:
-16.5<(D1m-d1s)/(CT1-T12-CP1)<-0.5，
wherein D1m is an outer diameter of an image-side surface of the first spacer element, D1s is an inner diameter of an object-side surface of the first spacer element, CT1 is a center thickness of the first lens, T12 is an air gap between the first lens and the second lens along the optical axis, and CP1 is a maximum thickness of the first spacer element.
13. The imaging system of any of claims 1 to 8, wherein the imaging system satisfies:
2.5<(D2s/d2m)+(R3/CT2)<7.0，
wherein D2s is an outer diameter of an object-side surface of the second spacer element, D2m is an inner diameter of an image-side surface of the second spacer element, R3 is a radius of curvature of an object-side surface of the second lens, and CT2 is a center thickness of the second lens.
14. The imaging system of any of claims 1 to 8, wherein the imaging system satisfies:
0<(T23+T34)/(CP1+CP2)<10.0，
wherein T23 is an air gap between the second lens and the third lens along the optical axis, T34 is an air gap between the third lens and the fourth lens along the optical axis, CP1 is a maximum thickness of the first spacer element, and CP2 is a maximum thickness of the second spacer element.
15. The imaging system of any of claims 1 to 8, wherein the imaging system satisfies:
9.5<(CT4+EP23)/(EP34-CT3)<17.4，
where CT4 is a central thickness of the fourth lens element, EP23 is a distance between an image-side surface of the second spacer element and an object-side surface of the third spacer element along the optical axis, CT3 is a central thickness of the third lens element, and EP34 is a distance between the image-side surface of the third spacer element and the object-side surface of the fourth spacer element along the optical axis.
16. The imaging system of any of claims 1 to 8, wherein the imaging system satisfies:
-41.5mm -1 <(d4m-d4s+D4s)/(R8*T45)<-9.0mm -1 ，
wherein D4m is an inner diameter of an image-side surface of the fourth spacer element, D4s is an inner diameter of an object-side surface of the fourth lens element, D4s is an outer diameter of the object-side surface of the fourth spacer element, R8 is a radius of curvature of the image-side surface of the fourth lens element, and T45 is an air gap between the fourth lens element and the fifth lens element along the optical axis.
17. The imaging system of any of claims 1 to 8, wherein the imaging system satisfies:
0<(R10+R11)*FNO/(D5s-D4m)<8.0，
wherein R10 is a radius of curvature of an image-side surface of the fifth lens element, R11 is a radius of curvature of an object-side surface of the sixth lens element, FNO is an aperture value of the imaging system, D5s is an outer diameter of an object-side surface of the fifth spacer element, and D4m is an outer diameter of an image-side surface of the fourth spacer element.
18. The imaging system of any of claims 1 to 8, wherein the imaging system satisfies:
7.5<(D5m+d5m)/(T56-CP5+CT5)<25.5，
wherein D5m is an outer diameter of an image-side surface of the fifth spacer element, D5m is an inner diameter of an image-side surface of the fifth lens, T56 is an air gap between the fifth lens and the sixth lens along the optical axis, CP5 is a maximum thickness of the fifth spacer element, and CT5 is a center thickness of the fifth lens.
19. The imaging system of any of claims 1 to 8, wherein the imaging system satisfies:
4.0<|f/R9*(D5m/EP45)|<22.5，
where f is the total effective focal length of the imaging system, R9 is the radius of curvature of the object-side surface of the fifth lens element, D5m is the outer diameter of the image-side surface of the fifth spacer element, and EP45 is the distance along the optical axis between the image-side surface of the fourth spacer element and the object-side surface of the fifth spacer element.
20. The imaging system of any of claims 1 to 8, wherein the imaging system satisfies:
0.5mm -1 <(TD*tan(Semi-FOV)/(∑CP*D5s)<14.0mm -1 ，
wherein TD is a distance along the optical axis from an object-side surface of the first lens to an image-side surface of the sixth lens, semi-FOV is a maximum half field angle of the imaging system, Σ CP is a sum of maximum thicknesses of the respective spacer elements of the first spacer element to the fifth spacer element, and D5s is an outer diameter of an object-side surface of the fifth spacer element.
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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117389009A (en) * 2023-12-11 2024-01-12 江西联创电子有限公司 Optical lens

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN117389009A (en) * 2023-12-11 2024-01-12 江西联创电子有限公司 Optical lens
CN117389009B (en) * 2023-12-11 2024-03-08 江西联创电子有限公司 Optical lens

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