CN112505891A

CN112505891A - Optical imaging lens matched with liquid lens

Info

Publication number: CN112505891A
Application number: CN202011491169.3A
Authority: CN
Inventors: 郑毅; 黄翔邦; 李可
Original assignee: Xiamen Leading Optics Co Ltd
Current assignee: Xiamen Leading Optics Co Ltd
Priority date: 2020-12-17
Filing date: 2020-12-17
Publication date: 2021-03-16

Abstract

The invention relates to the technical field of lenses. The invention discloses an optical imaging lens matched with a liquid lens, which sequentially comprises a first lens, a second lens, a third lens, a fourth lens, a diaphragm, the liquid lens, a fifth lens, a fourth lens, a diaphragm, a liquid lens, a fifth lens and an eighth lens from an object side to an image side along an optical axis, and each lens is correspondingly designed; the invention also discloses another optical imaging lens matched with the liquid lens, which sequentially comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a diaphragm, a liquid lens, a sixth lens and an eleventh lens from an object side to an image side along an optical axis, and all the lenses are correspondingly designed. The invention has the advantages of considering parameters such as resolution, depth of field, magnification and the like, along with wide range of working object distance, higher resolution, good imaging quality, large light transmission, high contrast and high production yield.

Description

Optical imaging lens matched with liquid lens

Technical Field

The invention belongs to the technical field of lenses, and particularly relates to an optical imaging lens matched with a liquid lens and used for machine vision.

Background

With the continuous progress of scientific technology and the continuous development of society, in recent years, optical imaging lenses are also rapidly developed, and the optical imaging lenses are widely applied to various fields such as smart phones, tablet computers, video conferences, vehicle-mounted monitoring, security monitoring, machine vision systems and the like, so that the requirements on the optical imaging lenses are higher and higher.

However, the optical imaging lens matched with the liquid lens and used for the machine vision system in the market at present has many defects, such as the light passing value does not reach the ideal light passing value required by the application; parameters such as resolution, depth of field, magnification and the like cannot be taken into consideration, the identification range is limited, and an object to be detected can be identified when the object is located in a specified small range; poor yield rate of production; the relative illumination is limited by the liquid lens, and the relative illumination is poor, so that the increasingly improved requirements cannot be met, and the improvement is urgently needed.

Disclosure of Invention

The present invention is directed to an optical imaging lens with a liquid lens, which is used to solve the above-mentioned problems.

In order to achieve the purpose, the invention adopts the technical scheme that: an optical imaging lens matched with a liquid lens sequentially comprises a first lens, a second lens, a third lens, a fourth lens, a diaphragm, the liquid lens, a fifth lens, a fourth lens, a fifth lens and an eighth lens from an object side to an image side along an optical axis; the first lens element to the eighth lens element each include an object-side surface facing the object side and allowing the imaging light to pass therethrough and an image-side surface facing the image side and allowing the imaging light to pass therethrough;

the first lens element with negative refractive index has a convex object-side surface and a concave image-side surface;

the second lens element with positive refractive index has a convex object-side surface and a convex image-side surface;

the third lens element with positive refractive index has a convex object-side surface and a concave image-side surface;

the fourth lens element with negative refractive index has a convex object-side surface and a concave image-side surface;

the fifth lens element with negative refractive index has a concave object-side surface and a concave image-side surface;

the sixth lens element with positive refractive index has a convex object-side surface and a convex image-side surface;

the seventh lens element has positive refractive index; the object side surface of the seventh lens is a convex surface, and the image side surface of the seventh lens is a convex surface;

the eighth lens element with negative refractive index has a concave object-side surface and a convex image-side surface;

the third lens and the fourth lens are mutually glued, and the fifth lens and the sixth lens are mutually glued;

the optical imaging lens has only the first lens element to the eighth lens element with refractive index.

The invention also provides another optical imaging lens matched with the liquid lens, which sequentially comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a diaphragm, a liquid lens, a sixth lens, a fifth lens, a diaphragm, a liquid lens and an eleventh lens from an object side to an image side along an optical axis; the first lens element to the eleventh lens element each include an object-side surface facing the object side and passing the imaging light, and an image-side surface facing the image side and passing the imaging light;

the second lens element with positive refractive index has a convex object-side surface and a convex or planar image-side surface;

the third lens element with positive refractive index has a convex object-side surface and a convex image-side surface;

the fourth lens element with negative refractive index has a concave object-side surface and a concave or planar image-side surface;

the sixth lens element with positive refractive index has a convex image-side surface;

the seventh lens element with negative refractive index has a concave object-side surface and a convex image-side surface;

the eighth lens element has positive refractive index; the image side surface of the eighth lens is a convex surface;

the ninth lens element has a negative refractive index, and the object-side surface of the ninth lens element is concave;

the tenth lens element with negative refractive power has a concave object-side surface and a convex image-side surface;

the eleventh lens element with negative refractive power has a concave object-side surface and a convex image-side surface;

the third lens and the fourth lens are mutually glued;

the optical imaging lens has only the first lens element to the eleventh lens element with refractive index.

Further, the sixth lens and the seventh lens are cemented with each other, and the eighth lens and the ninth lens are cemented with each other.

Further, the optical imaging lens further satisfies the following conditions: 1.85 to nd3 is more than or equal to nd4 to more than 1.5, and nd3 to nd4 is more than or equal to 0.13; 1.85 is not less than nd11 is not less than nd10 is more than 1.65, wherein nd3 is the refractive index of the third lens, nd4 is the refractive index of the fourth lens, nd10 is the refractive index of the tenth lens, and nd11 is the refractive index of the eleventh lens.

Further, the optical imaging lens further satisfies the following conditions: 1.2< f34/f <1.5, wherein f34 is the combined focal length of the third lens and the fourth lens, and f is the focal length of the optical imaging lens.

Further, the optical imaging lens further satisfies the following conditions: nd1 is more than or equal to nd2 and more than 1.6, wherein nd1 is the refractive index of the first lens, and nd2 is the refractive index of the second lens.

Further, the optical imaging lens further satisfies the following conditions: 0.75<f_{Rear group}/f<1.1 wherein f_{Rear group}The focal length of all the lenses on the image side of the liquid lens is the combined focal length, and f is the focal length of the optical imaging lens.

Further, the optical imaging lens further satisfies the following conditions: 0.85< f0/f <1.2, wherein f0 is a combined focal length of two lenses which are positioned at the image side of the liquid lens and closest to the liquid lens, and f is a focal length of the optical imaging lens.

Further, the optical imaging lens further satisfies the following conditions: gstop is larger than or equal to 17mm, wherein the Gstop is the sum of distances of the optical axis of the diaphragm and the image side surface of the first lens from the diaphragm to the object side and the distance of the optical axis of the object side surface of the first lens from the diaphragm to the image side.

Further, the optical imaging lens further satisfies the following conditions: TTL is less than or equal to 3.6f, wherein TTL is the distance between the object side surface of the first lens and the imaging surface on the optical axis, and f is the focal length of the optical imaging lens.

The invention has the beneficial technical effects that:

the invention gives consideration to the parameters of resolution, depth of field, magnification and the like, has wide working distance, and when the invention is used for identifying and detecting machine vision, an identified object does not need to be positioned in a specific small range, thereby realizing more rapid target identification; the resolution ratio is high, and the imaging quality is good; the light passing is large, and the relative illumination is high; the yield of the mass production is high (reaching 80 percent aiming at a 4K resolution sensor).

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a schematic structural diagram according to a first embodiment of the present invention;

FIG. 2 is a graph of the MTF of 0.435-0.656 μm in visible light at a 500mm object distance according to an embodiment of the present invention;

FIG. 3 is a graph of the MTF of 0.435-0.656 μm in visible light for a 200mm work object distance in accordance with an embodiment of the present invention;

FIG. 4 is a graph of the MTF of 0.435-0.656 μm in visible light for a 1000mm work object distance in accordance with an embodiment of the present invention;

FIG. 5 is a graph of the MTF of 0.435-0.656 μm in visible light for a 2000mm work object distance in accordance with an embodiment of the present invention;

FIG. 6 is a defocus graph of 60lp/mm in visible light 0.435-0.656 μm at a working object distance of 500mm in the embodiment of the present invention;

FIG. 7 is a schematic diagram of curvature of field and distortion of a first embodiment of the present invention;

FIG. 8 is a graph of relative illuminance in accordance with a first embodiment of the present invention;

FIG. 9 is a schematic structural diagram according to a second embodiment of the present invention;

FIG. 10 is a graph of the MTF of 0.435-0.656 μm in visible light at a distance of two 500mm work objects according to the embodiment of the present invention;

FIG. 11 is a graph of the MTF of 0.435-0.656 μm in visible light at a working object distance of two 200mm according to the embodiment of the present invention;

FIG. 12 is a graph of the MTF of 0.435-0.656 μm in visible light for two 1000mm working object distances in accordance with an embodiment of the present invention;

FIG. 13 is a graph of the MTF of 0.435-0.656 μm in visible light for a second 2000mm work object distance in accordance with an embodiment of the present invention;

FIG. 14 is a defocus graph of 60lp/mm in visible light of 0.435-0.656 μm at a working object distance of two 500mm according to the embodiment of the present invention;

FIG. 15 is a schematic view of curvature of field and distortion of a second embodiment of the present invention;

FIG. 16 is a graph showing relative illuminance in a second embodiment of the present invention;

FIG. 17 is a schematic structural diagram of a third embodiment of the present invention;

FIG. 18 is a graph of the MTF of 0.435-0.656 μm in the visible light for three 500mm work object distances in accordance with an embodiment of the present invention;

FIG. 19 is a graph of the MTF of 0.435-0.656 μm in visible light for three 200mm work object distances in accordance with an embodiment of the present invention;

FIG. 20 is a graph of the MTF of 0.435-0.656 μm in visible light for three 1000mm work object distances in accordance with an embodiment of the present invention;

FIG. 21 is a graph of the MTF of 0.435-0.656 μm in the visible light for a three 2000mm work object distance in accordance with an embodiment of the present invention;

FIG. 22 is a defocus plot of 60lp/mm in visible light 0.435-0.656 μm at a working object distance of three 500mm in the embodiment of the present invention;

FIG. 23 is a graphical illustration of curvature of field and distortion for a third embodiment of the present invention;

FIG. 24 is a graph showing relative illuminance in a third embodiment of the present invention;

FIG. 25 is a schematic structural diagram according to a fourth embodiment of the present invention;

FIG. 26 is a graph of the MTF of 0.435-0.656 μm in the visible at four 500mm work object distances according to an embodiment of the present invention;

FIG. 27 is a graph of the MTF of 0.435-0.656 μm in visible light for four 200mm work object distances in accordance with an embodiment of the present invention;

FIG. 28 is a graph of the MTF of 0.435-0.656 μm in visible light for a four 1000mm work object distance in accordance with an embodiment of the present invention;

FIG. 29 is a graph of the MTF of 0.435-0.656 μm in the visible at a four 2000mm work object distance in accordance with an embodiment of the present invention;

FIG. 30 is a defocus plot of 0.435-0.656 μm visible light at 60lp/mm for a four 500mm work object distance in accordance with an embodiment of the present invention;

FIG. 31 is a graphical illustration of field curvature and distortion for a fourth embodiment of the present invention;

FIG. 32 is a graph of relative illuminance for the fourth embodiment of the present invention;

FIG. 33 is a schematic structural diagram of a fifth embodiment of the present invention;

FIG. 34 is a graph of the MTF of 0.435-0.656 μm in visible light for a five 500mm work object distance in accordance with an embodiment of the present invention;

FIG. 35 is a graph of the MTF of 0.435-0.656 μm in visible light for five 200mm work object distances in accordance with an embodiment of the present invention;

FIG. 36 is a graph of the MTF of 0.435-0.656 μm in visible light for a five 1000mm work object distance in accordance with an embodiment of the present invention;

FIG. 37 is a graph of the MTF of 0.435-0.656 μm in visible light for a five 2000mm work object distance in accordance with an embodiment of the present invention;

FIG. 38 is a defocus plot of 0.435-0.656 μm visible light at 60lp/mm for a five 500mm work object distance in accordance with an embodiment of the present invention;

FIG. 39 is a graphical illustration of field curvature and distortion for example five of the present invention;

fig. 40 is a graph showing relative illuminance in fifth embodiment of the present invention.

Detailed Description

To further illustrate the various embodiments, the invention provides the accompanying drawings. The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the embodiments. Those skilled in the art will appreciate still other possible embodiments and advantages of the present invention with reference to these figures. Elements in the figures are not drawn to scale and like reference numerals are generally used to indicate like elements.

The invention will now be further described with reference to the accompanying drawings and detailed description.

As used herein, the term "a lens element having a positive refractive index (or a negative refractive index)" means that the paraxial refractive index of the lens element calculated by Gaussian optics is positive (or negative). The term "object-side (or image-side) of a lens" is defined as the specific range of imaging light rays passing through the lens surface. The determination of the surface shape of the lens can be performed by the judgment method of a person skilled in the art, i.e., by the sign of the curvature radius (abbreviated as R value). The R value may be commonly used in optical design software, such as Zemax or CodeV. The R value is also commonly found in lens data sheets (lens data sheets) of optical design software. When the R value is positive, the object side is judged to be a convex surface; and when the R value is negative, judging that the object side surface is a concave surface. On the contrary, regarding the image side surface, when the R value is positive, the image side surface is judged to be a concave surface; when the R value is negative, the image side surface is judged to be convex.

The invention discloses an optical imaging lens matched with a liquid lens, which sequentially comprises a first lens, a second lens, a third lens, a fourth lens, a diaphragm, a liquid lens, a fifth lens and an eighth lens from an object side to an image side along an optical axis; the first lens element to the eighth lens element each include an object-side surface facing the object side and passing the image light, and an image-side surface facing the image side and passing the image light.

The first lens element with negative refractive power has a convex object-side surface and a concave image-side surface, and has pre-refraction effect.

The second lens element has a positive refractive index, a convex object-side surface and a convex image-side surface, and is a drum-shaped lens element for reducing high-order aberration.

The third lens element with positive refractive power has a convex object-side surface and a concave image-side surface.

The fourth lens element has a negative refractive index, the object-side surface of the fourth lens element is convex, the image-side surface of the fourth lens element is concave, and the third lens element and the fourth lens element are cemented with each other to better correct the chromatic aberration of the system.

The fifth lens element with negative refractive index has a concave object-side surface and a concave image-side surface.

The sixth lens element has a positive refractive index, an object-side surface of the sixth lens element is a convex surface, an image-side surface of the sixth lens element is a convex surface, and the fifth lens element and the sixth lens element are cemented with each other to compress the height of the outgoing light of the liquid lens element and correct the chromatic aberration of the system.

The seventh lens element has positive refractive index; the object side surface of the seventh lens element is convex, and the image side surface of the seventh lens element is convex.

The eighth lens element with negative refractive index has a concave object-side surface and a convex image-side surface.

The invention also provides another optical imaging lens matched with the liquid lens, which sequentially comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a diaphragm, a liquid lens, a sixth lens, a fifth lens, a diaphragm, a liquid lens and an eleventh lens from an object side to an image side along an optical axis; the first lens element to the eleventh lens element each include an object-side surface facing the object side and passing the image light, and an image-side surface facing the image side and passing the image light.

The second lens element has positive refractive index, the object-side surface of the second lens element is convex, the image-side surface of the second lens element is convex or planar, and the second lens element compresses the height of light rays to reduce high-order aberration.

The third lens element with positive refractive power has a convex object-side surface and a convex image-side surface.

The fourth lens element with negative refractive index has a concave object-side surface and a concave or planar image-side surface.

The third lens and the fourth lens are mutually glued to correct the chromatic aberration of the system, the fifth lens further compresses the light height and adjusts the optical angle, so that the light beams can be approximately parallel to the optical axis and pass through the diaphragm and the liquid lens, and the influence of the liquid lens on the sensitivity and the relative illumination of the system is reduced.

The sixth lens element with positive refractive power has a convex image-side surface.

The seventh lens element with negative refractive index has a concave object-side surface and a convex image-side surface.

The eighth lens element has positive refractive index; the image side surface of the eighth lens is convex.

The ninth lens element has a negative refractive index, and an object-side surface of the ninth lens element is concave.

The tenth lens element with negative refractive power has a concave object-side surface and a convex image-side surface.

The eleventh lens element with negative refractive power has a concave object-side surface and a convex image-side surface, and the tenth and eleventh lens elements are meniscus lenses for adjusting the curvature of field of the system.

Preferably, in the solution with eleven lenses, the sixth lens and the seventh lens are cemented with each other to compress the height of the outgoing light of the liquid lens, so as to better correct the system chromatic aberration, and the eighth lens and the ninth lens are cemented with each other to compress the optical height, so as to further correct the system chromatic aberration.

Preferably, in a scheme with eleven lenses, the optical imaging lens further satisfies the following conditions: 1.85 nd3 is more than or equal to nd4 and more than or equal to 1.5, nd3-nd4 is more than or equal to 0.13, the monochromatic aberration of the system is further corrected, and the spherical aberration is optimized; 1.85 is more than or equal to nd11 is more than or equal to nd10 and more than 1.65, and the image height of the system is ensured by matching with optical power distribution, wherein nd3 is the refractive index of the third lens, nd4 is the refractive index of the fourth lens, nd10 is the refractive index of the tenth lens, and nd11 is the refractive index of the eleventh lens.

Preferably, in a scheme with eleven lenses, the optical imaging lens further satisfies the following conditions: 1.2< f34/f <1.5, wherein f34 is the combined focal length of the third lens and the fourth lens, and f is the focal length of the optical imaging lens.

Preferably, the optical imaging lens further satisfies: nd1 is more than or equal to nd2 and more than 1.6, wherein nd1 is the refractive index of the first lens, nd2 is the refractive index of the second lens, the first lens and the second lens form a positive lens group and a negative lens group, and the factors limiting the system image quality improvement by the large primary aberration which can be generated by the original single negative lens and the very large high-order aberration which can be accompanied by, in particular the vertical axis aberration (coma, distortion, chromatic aberration of magnification and the like) related to the field of view are further optimized.

Preferably, the optical imaging lens further satisfies: 0.75<f_{Rear group}/f<1.1 wherein f_{Rear group}The combined focal length of all the lenses positioned on the image side of the liquid lens, and f is the focal length of the optical imaging lens, and the proper focal power is provided for the whole optical system.

Preferably, the optical imaging lens further satisfies: 0.85< f0/f <1.2, wherein f0 is the combined focal length of two lenses which are positioned at the image side of the liquid lens and are closest to the liquid lens, and f is the focal length of the optical imaging lens, the height of light rays entering a rear group is compressed, the optimization difficulty of field-related aberration is reduced, and the size of the rear group lens is controlled.

Preferably, the optical imaging lens further satisfies: gstop is larger than or equal to 17mm, wherein the Gstop is the sum of distances of the optical axis of the diaphragm and the image side surface of the first lens from the diaphragm to the object side and the distance of the optical axis of the object side surface of the first lens from the diaphragm to the image side. The diaphragm interval is increased, the iris diaphragm function is realized, the liquid lens with the maximum 16mm caliber can be adapted, the diaphragm adaptation can be adjusted by matching the condition of the liquid lens with the small caliber, and the attenuation of the relative illumination caused by the reduction of optical parameters and excessive vignetting due to the caliber limitation of the liquid lens is avoided.

Preferably, the optical imaging lens further satisfies: TTL is less than or equal to 3.6f, wherein TTL is the distance between the object side surface of the first lens and the imaging surface on the optical axis, and f is the focal length of the optical imaging lens, and the system length of the optical imaging lens is further shortened.

The following describes the optical imaging lens with liquid lens according to the present invention in detail with specific embodiments.

Example one

As shown in fig. 1, an optical imaging lens incorporating a liquid lens includes, in order from an object side a1 to an image side a2 along an optical axis I, a first lens element 1, a second lens element 2, a third lens element 3, a fourth lens element 4, a diaphragm 100, a liquid lens element 9, a fifth lens element 5, a sixth lens element 6, a seventh lens element 7, an eighth lens element 8, a protective glass 110, and an image plane 120; the first lens element 1 to the eighth lens element 8 each include an object-side surface facing the object side a1 and passing the imaging light rays, and an image-side surface facing the image side a2 and passing the imaging light rays.

The first lens element 1 has a negative refractive index, and an object-side surface 11 of the first lens element 1 is convex and an image-side surface 12 of the first lens element 1 is concave.

The second lens element 2 has a positive refractive index, and an object-side surface 21 of the second lens element 2 is convex and an image-side surface 22 of the second lens element 2 is convex.

The third lens element 3 has a positive refractive index, and an object-side surface 31 of the third lens element 3 is convex and an image-side surface 32 of the third lens element 3 is concave.

The fourth lens element 4 has a negative refractive index, and an object-side surface 41 of the fourth lens element 4 is convex and an image-side surface 42 of the fourth lens element 4 is concave.

The fifth lens element 5 has a negative refractive index, and an object-side surface 51 of the fifth lens element 5 is concave and an image-side surface 52 of the fifth lens element 5 is concave.

The sixth lens element 6 has a positive refractive index, and an object-side surface 61 of the sixth lens element 6 is convex and an image-side surface 62 of the sixth lens element 6 is convex.

The seventh lens element 7 has a positive refractive index; the object-side surface 71 of the seventh lens element 7 is convex, and the image-side surface 72 of the seventh lens element 7 is convex.

The eighth lens element 8 has a negative refractive index, and an object-side surface 81 of the eighth lens element 8 is concave and an image-side surface 82 of the eighth lens element 8 is convex.

The third lens 3 and the fourth lens 4 are cemented with each other, and the fifth lens 5 and the sixth lens 6 are cemented with each other

The liquid lens 100 is a conventional liquid lens, and the specific structure can refer to the prior art, which is not described in detail.

The detailed optical data of this embodiment are shown in Table 1-1.

Table 1-1 detailed optical data for example one

Please refer to table 6 for the values of the conditional expressions related to this embodiment.

The MTF transfer function graphs of different working object distances of the embodiment are shown in fig. 2, 3, 4 and 5 in detail, it can be seen that the working object distance range is wide (200mm-2000mm), the resolution can meet the use of a 4K resolution sensor, and parameters such as resolution, depth of field and magnification are taken into consideration; the defocusing graph is shown in detail in FIG. 6, and it can be seen that the imaging quality is better; referring to (a) and (B) of fig. 7, it can be seen that the field curvature and distortion are small, the distortion amount is less than 2.5%, and the contrast curve is detailed in fig. 8, it can be seen that the contrast is high, higher than 0.7.

In this embodiment, the focal length f of the optical imaging lens is 24.7 mm; f-number FNO 2.8; field angle FOV is 37.4 °; the size of an image plane is 17.6 mm; the distance TTL between the object side surface 11 of the first lens element 1 and the image plane 120 on the optical axis I is 79.01 mm.

Example two

As shown in fig. 9, the lens elements of this embodiment have the same surface roughness and refractive index as those of the first embodiment, and only the optical parameters such as the curvature radius and the lens thickness of the surface of each lens element are different.

The detailed optical data of this embodiment is shown in Table 2-1.

TABLE 2-1 detailed optical data for example two

The MTF transfer function graphs of different working object distances of the embodiment are shown in fig. 10, 11, 12 and 13 in detail, it can be seen that the working object distance range is wide (200mm-2000mm), the resolution can meet the use of a 4K resolution sensor, and parameters such as resolution, depth of field and magnification are taken into consideration; the defocusing graph is shown in detail in fig. 14, and it can be seen that the imaging quality is better; referring to (a) and (B) of fig. 15, it can be seen that the field curvature and distortion are small, the distortion amount is less than 2.0%, and the contrast curve is detailed in fig. 16, it can be seen that the contrast is high, higher than 0.7.

In this embodiment, the focal length f of the optical imaging lens is 24.7 mm; f-number FNO 2.8; field angle FOV is 38.0 °; the size of an image plane is 17.6 mm; the distance TTL between the object side surface 11 of the first lens element 1 and the image plane 120 on the optical axis I is 79.00 mm.

EXAMPLE III

As shown in fig. 17, an optical imaging lens incorporating a liquid lens includes, in order from an object side a1 to an image side a2 along an optical axis I, a first lens element 1, a second lens element 2, a third lens element 3, a fourth lens element 4, a fifth lens element 5, a stop 130, a liquid lens element 120, a sixth lens element 6, a seventh lens element 7, an eighth lens element 8, a ninth lens element 9, a tenth lens element 100, an eleventh lens element 110, a protective glass 140, and an image plane 150; the first lens element 1 to the eleventh lens element 110 each include an object-side surface facing the object side a1 and passing the image light, and an image-side surface facing the image side a2 and passing the image light.

The second lens element 2 has positive refractive power, the object-side surface 21 of the second lens element 2 is convex, and the image-side surface 22 of the second lens element 2 is convex, although in some embodiments, the image-side surface 22 of the second lens element 2 may also be planar.

The third lens element 3 has a positive refractive index, and an object-side surface 31 of the third lens element 3 is convex and an image-side surface 32 of the third lens element 3 is convex.

The fourth lens element 4 has negative refractive power, the object-side surface 41 of the fourth lens element 4 is concave, and the image-side surface 42 of the fourth lens element 4 is concave, although in some embodiments, the image-side surface 42 of the fourth lens element 4 can also be flat.

The sixth lens element 6 has positive refractive power, the object-side surface 61 of the sixth lens element 6 is convex, and the image-side surface 62 of the sixth lens element 6 is convex, although in some embodiments, the object-side surface 61 of the sixth lens element 6 may also be concave or planar.

The seventh lens element 7 has a negative refractive index, and an object-side surface 71 of the seventh lens element 7 is concave and an image-side surface 72 of the seventh lens element 7 is convex.

The eighth lens element 8 has a positive refractive index; the object-side surface 81 of the eighth lens element 8 is convex, and the image-side surface 82 of the eighth lens element 8 is convex, although in some embodiments, the object-side surface 81 of the eighth lens element 8 may also be concave or planar.

The ninth lens element 9 has a negative refractive index, the object-side surface 91 of the ninth lens element 9 is concave, and the image-side surface 92 of the ninth lens element 9 is planar, but may also be concave or convex on the image-side surface 92 of the ninth lens element 9.

The tenth lens element 100 with negative refractive power has a concave object-side surface 101 of the tenth lens element 100 and a convex image-side surface 102 of the tenth lens element 100.

The eleventh lens element 110 has a negative refractive index, and the object-side surface 110 of the eleventh lens element 110 is concave and the image-side surface 102 of the eleventh lens element 110 is convex.

In this embodiment, the third lens 3 and the fourth lens 4 are cemented with each other, the sixth lens 6 and the seventh lens 7 are cemented with each other, and the eighth lens 8 and the ninth lens 9 are cemented with each other, but of course, in some embodiments, the sixth lens 6 and the seventh lens 7 may not be cemented, and the eighth lens 8 and the ninth lens 9 may not be cemented.

In this embodiment, the sixth lens 6 is preferably a positive crown lens and the seventh lens 7 is preferably a negative flint lens.

The liquid lens 120 is an existing liquid lens, and the specific structure can refer to the prior art, which is not described in detail.

The detailed optical data of this embodiment is shown in Table 3-1.

TABLE 3-1 detailed optical data for EXAMPLE III

The MTF transfer function graphs of different working object distances in the embodiment are shown in fig. 18, 19, 20 and 21 in detail, and it can be seen that the working object distance range is wide (200mm-2000mm), the resolution can meet the use of a 4K resolution sensor, and parameters such as resolution, depth of field and magnification are taken into consideration; the defocusing graph is shown in detail in FIG. 22, and it can be seen that the imaging quality is better; referring to (a) and (B) of fig. 23, it can be seen that the field curvature and distortion are small, the distortion amount is less than-2.0%, and the contrast curve is detailed in fig. 24, it can be seen that the contrast is high, higher than 0.7.

In this embodiment, the focal length f of the optical imaging lens is 24.6 mm; f-number FNO 2.8; field angle FOV is 38.9 °; the size of an image plane is 17.6 mm; the distance TTL between the object side surface 11 of the first lens element 1 and the image plane 120 on the optical axis I is 87.73 mm.

Compared with the first embodiment and the second embodiment, the imaging quality is better, but correspondingly, the optical total length of the embodiment is longer, the number of lenses is larger, and the cost is higher.

Example four

As shown in fig. 25, the lens elements of this embodiment have the same surface irregularities and refractive index as those of the lens element of the third embodiment, and only the optical parameters such as the curvature radius and the lens thickness of the lens element surface are different.

The detailed optical data of this embodiment is shown in Table 4-1.

TABLE 4-1 detailed optical data for example four

The MTF transfer function graphs of different working object distances of the embodiment are shown in fig. 26, 27, 28 and 29 in detail, so that the working object distance range is wide, the resolution can meet the use requirement of a 4K resolution sensor, and parameters such as resolution, depth of field, magnification and the like are considered; the defocusing curve graph is shown in detail in fig. 30, and it can be seen that the imaging quality is better; referring to (a) and (B) of fig. 31, it can be seen that the field curvature and distortion are small, the distortion amount is less than-2.0%, and the contrast curve is detailed in fig. 32, and it can be seen that the contrast is high, higher than 0.7.

In this embodiment, the focal length f of the optical imaging lens is 24.7 mm; f-number FNO 2.8; field angle FOV is 38.7 °; the size of an image plane is 17.6 mm; the distance TTL between the object side surface 11 of the first lens element 1 and the image plane 120 on the optical axis I is 87.09 mm.

EXAMPLE five

As shown in fig. 33, the lens elements of this embodiment have the same surface irregularities and refractive index as those of the lens elements of the third embodiment, and only the optical parameters such as the curvature radius and the lens thickness of the lens element surface are different.

The detailed optical data of this embodiment is shown in Table 5-1.

TABLE 5-1 detailed optical data for EXAMPLE V

The MTF transfer function graphs of different working object distances of the embodiment are shown in fig. 34, 35, 36 and 37 in detail, it can be seen that the working object distance range is wide, the resolution can meet the use of a 4K resolution sensor, and parameters such as resolution, depth of field and magnification are taken into consideration; the defocusing graph is shown in detail in fig. 38, and it can be seen that the imaging quality is better; referring to (a) and (B) of fig. 39, it can be seen that the field curvature and distortion are small, the distortion amount is less than-1.5%, and the contrast curve is detailed in fig. 40, it can be seen that the contrast is high, higher than 0.7.

In this embodiment, the focal length f of the optical imaging lens is 26.2 mm; f-number FNO 2.8; field angle FOV is 36.4 °; the size of an image plane is 17.6 mm; the distance TTL between the object side surface 11 of the first lens element 1 and the image plane 120 on the optical axis I is 87.31 mm.

TABLE 6 values of relevant important parameters for five embodiments of the invention

While the invention has been particularly shown and described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. The utility model provides a collocation liquid lens's optical imaging lens which characterized in that: the liquid lens comprises a first lens, a second lens, a third lens, a fourth lens, a diaphragm, a liquid lens, a fifth lens and an eighth lens in sequence from an object side to an image side along an optical axis; the first lens element to the eighth lens element each include an object-side surface facing the object side and allowing the imaging light to pass therethrough and an image-side surface facing the image side and allowing the imaging light to pass therethrough;

2. The utility model provides a collocation liquid lens's optical imaging lens which characterized in that: the liquid lens comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a diaphragm, a liquid lens, a sixth lens, a fifth lens, a sixth lens and an eleventh lens in sequence from an object side to an image side along an optical axis; the first lens element to the eleventh lens element each include an object-side surface facing the object side and passing the imaging light, and an image-side surface facing the image side and passing the imaging light;

the third lens and the fourth lens are mutually glued;

3. The optical imaging lens matched with a liquid lens as claimed in claim 2, wherein: the sixth lens and the seventh lens are cemented with each other, and the eighth lens and the ninth lens are cemented with each other.

4. The optical imaging lens matched with a liquid lens of claim 2, wherein the optical imaging lens further satisfies: 1.85 to nd3 is more than or equal to nd4 to more than 1.5, and nd3 to nd4 is more than or equal to 0.13; 1.85 is not less than nd11 is not less than nd10 is more than 1.65, wherein nd3 is the refractive index of the third lens, nd4 is the refractive index of the fourth lens, nd10 is the refractive index of the tenth lens, and nd11 is the refractive index of the eleventh lens.

5. The optical imaging lens matched with a liquid lens of claim 2, wherein the optical imaging lens further satisfies: 1.2< f34/f <1.5, wherein f34 is the combined focal length of the third lens and the fourth lens, and f is the focal length of the optical imaging lens.

6. The optical imaging lens matched with a liquid lens of claim 1 or 2, wherein the optical imaging lens further satisfies: nd1 is more than or equal to nd2 and more than 1.6, wherein nd1 is the refractive index of the first lens, and nd2 is the refractive index of the second lens.

7. The optical imaging lens matched with a liquid lens of claim 1 or 2, wherein the optical imaging lens further satisfies: 0.75<f_{Rear group}/f<1.1 wherein f_{Rear group}The focal length of all the lenses on the image side of the liquid lens is the combined focal length, and f is the focal length of the optical imaging lens.

8. The optical imaging lens matched with a liquid lens of claim 1 or 2, wherein the optical imaging lens further satisfies: 0.85< f0/f <1.2, wherein f0 is a combined focal length of two lenses which are positioned at the image side of the liquid lens and closest to the liquid lens, and f is a focal length of the optical imaging lens.

9. The optical imaging lens matched with a liquid lens of claim 1 or 2, wherein the optical imaging lens further satisfies: gstop is larger than or equal to 17mm, wherein the Gstop is the sum of distances of the optical axis of the diaphragm and the image side surface of the first lens from the diaphragm to the object side and the distance of the optical axis of the object side surface of the first lens from the diaphragm to the image side.

10. The optical imaging lens matched with a liquid lens of claim 1 or 2, wherein the optical imaging lens further satisfies: TTL is less than or equal to 3.6f, wherein TTL is the distance between the object side surface of the first lens and the imaging surface on the optical axis, and f is the focal length of the optical imaging lens.