CN210488110U

CN210488110U - Optical imaging lens

Info

Publication number: CN210488110U
Application number: CN201921898735.5U
Authority: CN
Inventors: 刘青天; 李雪慧; 上官秋和
Original assignee: Xiamen Leading Optics Co Ltd
Current assignee: Xiamen Leading Optics Co Ltd
Priority date: 2019-11-06
Filing date: 2019-11-06
Publication date: 2020-05-08
Anticipated expiration: 2029-11-06

Abstract

The utility model relates to a camera lens technical field. The utility model discloses an optical imaging lens, which comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a fourth lens from an object side to an image side along an optical axis; the first lens is a convex-concave or convex-flat lens with positive refractive index; the second lens is a convex-concave lens with negative refractive index; the third lens element has a concave lens element with negative refractive index; the fourth lens is a convex lens with positive refractive index; the fifth lens is a convex-concave lens with negative refractive index; the first lens is made of glass materials, and the second lens to the fifth lens are all plastic aspheric lenses. The utility model has high resolution, high resolution and uniform image quality; the aberration and chromatic aberration are small, and the distortion is small; the coke has small variation under high temperature and low temperature, and basically has no field curvature.

Description

Optical imaging lens

Technical Field

The utility model belongs to the technical field of the camera lens, specifically relate to an optical imaging camera lens.

Background

With the continuous progress of science and technology, in recent years, the optical imaging lens is rapidly developed and widely applied to various fields such as smart phones, tablet computers, video conferences, vehicle-mounted monitoring, security monitoring and the like, so that the requirement on the optical imaging lens is higher and higher. However, in the general optical imaging lens for security monitoring in the current market, the transfer function control is poor, the resolution is low, the image sharpness is poor, and the uniformity is poor; the high-level aberration correction difficulty is high, and particularly at the edge, the color reducibility is poor; plastic aspheric lenses are completely used, temperature drift control is poor, and severe field curvature is caused due to severe defocus under high-temperature and low-temperature conditions; the distortion is not specially controlled, the optical distortion is more than 5%, the deformation amount of the image edge is large, the increasingly-improved requirements of consumers cannot be met, and the improvement is needed.

Disclosure of Invention

An object of the utility model is to provide an optical imaging lens is used for solving the technical problem that the above-mentioned exists.

In order to achieve the above object, the utility model adopts the following technical scheme: an optical imaging lens sequentially comprises a first lens, a second lens, a third lens, a fourth lens and a fifth lens from an object side to an image side along an optical axis; the first lens element to the fifth lens element respectively comprise an object side surface facing the object side and allowing the imaging light to pass and an image side surface facing the image side and allowing the imaging light to pass;

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

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

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

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

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

the first lens is made of glass materials, and the second lens to the fifth lens are all plastic aspheric lenses;

the optical imaging lens only has the five lenses with the refractive indexes.

Further, the optical diaphragm is arranged between the second lens and the third lens.

Further, the optical imaging lens further satisfies: vd4>50, wherein vd4 is the d-line abbe number of the fourth lens.

Further, the first lens is made of H-LAF52 glass material.

Further, the optical imaging lens further satisfies: t1 < 3mm, T2<1mm, T3<1mm, T4<5mm, and T5<1.2mm, wherein T1 is a central thickness of the first lens on the optical axis, T2 is a central thickness of the second lens on the optical axis, T3 is a central thickness of the third lens on the optical axis, T4 is a central thickness of the fourth lens on the optical axis, and T5 is a central thickness of the fifth lens on the optical axis.

Further, the optical imaging lens further satisfies: ALT <11mm, wherein ALT is a sum of five lens thicknesses of the first lens to the fifth lens on the optical axis.

Further, the optical imaging lens further satisfies: ALG <10.5mm, wherein ALG is the sum of air gaps between the first lens and an imaging surface on the optical axis.

Further, the optical imaging lens further satisfies: ALT/ALG <1.5, wherein ALT is the sum of five lens thicknesses of the first lens to the fifth lens on the optical axis, and ALG is the sum of air gaps between the first lens and an imaging surface on the optical axis.

The utility model has the advantages of:

the utility model adopts five lenses, and through corresponding design of each lens, the resolution ratio is high (reaching 280lp/mm > 0.3), the transmission function is strictly controlled, the resolving power is high, and the image quality of different fields is uniform; the aberration is small, the chromatic aberration is small (less than 1.8 mu m), and the color reducibility is strong; the after-coke variation is small under the conditions of high temperature and low temperature, and the field curvature phenomenon is basically avoided; the distortion is very small (DIS < 0.5%), and the distortion is almost not deformed.

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 described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a first embodiment of the present invention;

FIG. 2 is a graph of the MTF of the visible light 435-;

FIG. 3 is a defocus plot of 60lp/mm in visible light 435-;

fig. 4 is a schematic view of field curvature and distortion of the first embodiment of the present invention;

fig. 5 is a schematic view of vertical axis chromatic aberration according to a first embodiment of the present invention;

fig. 6 is a schematic view of a vertical axis aberration diagram according to a first embodiment of the present invention;

fig. 7 is a schematic structural diagram of a second embodiment of the present invention;

FIG. 8 is the MTF graph of visible light 435-;

FIG. 9 is a defocus plot of 60lp/mm in visible light 435-;

fig. 10 is a schematic view of curvature of field and distortion according to a second embodiment of the present invention;

fig. 11 is a schematic view of vertical axis chromatic aberration of a second embodiment of the present invention;

fig. 12 is a schematic view of vertical axis aberration diagram according to the second embodiment of the present invention;

fig. 13 is a schematic structural view of a third embodiment of the present invention;

FIG. 14 is the MTF graph of visible light 435-;

FIG. 15 is a defocus plot of 60lp/mm in visible light 435-;

fig. 16 is a schematic view of curvature of field and distortion according to a third embodiment of the present invention;

fig. 17 is a vertical axis chromatic aberration diagram of a third embodiment of the present invention;

fig. 18 is a schematic view of a vertical axis aberration diagram according to a third embodiment of the present invention;

fig. 19 is a table of values of relevant important parameters according to three embodiments of the present invention.

Detailed Description

To further illustrate the embodiments, the present 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. With these references, one of ordinary skill in the art will appreciate other possible embodiments and advantages of the present invention. Elements in the figures are not drawn to scale and like reference numerals are generally used to indicate like elements.

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

The term "a lens element having positive refractive index (or negative refractive index)" means that the paraxial refractive index of the lens element calculated by Gaussian optics theory 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 utility model discloses an optical imaging lens, which comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a fourth lens from an object side to an image side along an optical axis; the first lens element to the fifth 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 has positive refractive index, the object side surface of the first lens is a convex surface, the image side surface of the first lens is a concave surface or a plane, the first lens is made of glass materials, the cost is low, the hardness is high compared with that of plastic materials, the first lens is not easy to scratch and corrode, and a better protection effect is achieved.

The second lens element with negative refractive index has a convex object-side surface and a concave image-side surface, and is a plastic aspheric lens with less distortion and optimized aberration.

The third lens element with negative refractive index has a concave object-side surface and a concave image-side surface, and is a plastic aspheric lens element.

The fourth lens element with positive refractive index has a convex object-side surface and a convex image-side surface, and is a plastic aspheric lens element.

The fifth lens element with negative refractive index has a convex object-side surface and a concave image-side surface, and is a plastic aspheric lens element.

The second lens to the fifth lens are all plastic aspheric lenses, so that high-grade aberration and chromatic aberration can be better corrected, the imaging quality is improved, the whole image quality is uniformly distributed, and the color restoration is strong.

The optical imaging lens only has the five lenses with the refractive indexes. The utility model adopts five lenses, and through corresponding design of each lens, the resolution ratio is high, the transmission function is strictly controlled, the resolving power is high, and the image quality of different fields of view is uniform; the aberration is small, the chromatic aberration is small, and the color reducibility is strong; the after-coke variation is small under the conditions of high temperature and low temperature, and the field curvature phenomenon is basically avoided; the distortion is very small, and the image is in linear distribution and almost has no deformation.

Preferably, the optical imaging lens further comprises a diaphragm, the diaphragm is arranged between the second lens and the third lens, the system length of the optical imaging lens can be shortened, the image quality is optimized, the image side surface of the second lens and the object side surface of the third lens are symmetrical about the diaphragm, the high-order aberration is further corrected, the resolution is improved, and the whole resolution is uniformly distributed.

Preferably, the optical imaging lens further satisfies: vd4 is greater than 50, wherein vd4 is the d-line abbe number of the fourth lens element, and the d-line abbe number is matched with the plastic aspheric lens with negative refractive index, so that the high-temperature and low-temperature defocus problem and the field curvature phenomenon can be better improved, the aberration can be corrected, and the system performance can be better improved.

Preferably, the first lens is made of H-LAF52 glass material, and the expansion coefficient of the material is larger, so that the temperature drift effect is further improved.

Preferably, the optical imaging lens further satisfies: t1 is less than 3mm, T2 is less than 1mm, T3 is less than 1mm, T4 is less than 5mm, and T5 is less than 1.2mm, wherein T1 is the central thickness of the first lens on the optical axis, T2 is the central thickness of the second lens on the optical axis, T3 is the central thickness of the third lens on the optical axis, T4 is the central thickness of the fourth lens on the optical axis, and T5 is the central thickness of the fifth lens on the optical axis, so that the system length of the optical imaging lens is further shortened, the optical imaging lens is easy to manufacture, and the system configuration is optimized.

Preferably, the optical imaging lens further satisfies: ALT <11mm, wherein ALT is the sum of five lens thicknesses of the first lens to the fifth lens on the optical axis, so as to further shorten the system length of the optical imaging lens, and the optical imaging lens is easy to manufacture and optimize the system configuration.

Preferably, the optical imaging lens further satisfies: ALG <10.5mm, wherein ALG is the sum of air gaps between the first lens and an imaging surface on the optical axis, so that the system length of the optical imaging lens is further shortened, the processing and the manufacturing are easy, and the system configuration is optimized.

Preferably, the optical imaging lens further satisfies: ALT/ALG <1.5, wherein ALT is the total of five lens thicknesses of the first lens to the fifth lens on the optical axis, and ALG is the total of air gaps of the first lens to an imaging surface on the optical axis, so as to further shorten the system length of the optical imaging lens, and the optical imaging lens is easy to process and manufacture and optimizes the system configuration.

The optical imaging lens of the present invention will be described in detail with reference to specific embodiments.

Example one

As shown in fig. 1, an optical imaging lens includes, in order along an optical axis I, a first lens 1, a second lens 2, a stop 6, a third lens 3, a fourth lens 4, a fifth lens 5, an optical filter 7, a protective sheet 8, and an image plane 9 from an object side a1 to an image side a 2; the first lens element 1 to the fifth lens element 5 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 positive refractive index, the object-side surface 11 of the first lens element 1 is a convex surface, and the image-side surface 12 of the first lens element 1 is a flat surface.

The second lens element 2 has a negative 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 concave.

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

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

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

The first lens 1 is made of H-LAF52 glass material, but is not limited thereto.

The second lens 2 to the fifth lens 5 are all plastic aspheric lenses.

Of course, in other embodiments, the diaphragm 6 may be disposed in other positions.

In this embodiment, the filter 7 may be an infrared filter for filtering infrared light, but is not limited thereto.

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

Table 1-1 detailed optical data for example one

In this embodiment, the object-side surface 21, the object-side surface 31, the object-side surface 41, the object-side surface 51, the image-side surface 22, the image-side surface 32, the image-side surface 42, and the image-side surface 52 are defined by the following aspheric curve formulas:

wherein:

z: depth of the aspheric surface (the vertical distance between a point on the aspheric surface that is y from the optical axis and a tangent plane tangent to the vertex on the optical axis of the aspheric surface);

c: curvature of aspheric vertex (the vertex curvature);

k: cone coefficient (Conic Constant);

radial distance (radial distance);

r_n: normalized radius (normalysis radius (NRADIUS));

u：r/r_n；

a_m: mth order Q^conCoefficient (is the m)^thQ^concoefficient)；

Q_m ^con: mth order Q^conPolynomial (the m)^thQ^conpolynomial)；

For details of parameters of each aspheric surface, please refer to the following table:

please refer to fig. 19 for the values of the conditional expressions according to this embodiment.

The MTF transfer function curve chart of the specific embodiment is shown in detail in FIG. 2, and it can be seen that the image resolution is good, the resolution is high, the resolution reaches 280lp/mm which is more than 0.3, and the imaging quality is good; the defocusing curve graph at the temperature of 60 ℃ is shown in detail in fig. 3, fig. 3 is a temperature-drift defocusing curve graph under a single lens, if a holder (base) and a Barrel (frame) are matched, the defocusing can basically reach 0 degree, and the back focus is basically unchanged under the conditions of high temperature and low temperature; the field curvature and distortion diagram are shown in detail in (a) and (B) of fig. 4, and it can be seen that the field curvature is extremely small; the distortion is small, and the optical distortion is less than 0.5%; the vertical axis chromatic aberration diagram is detailed in a figure 5, and it can be seen that the chromatic aberration is small and is less than 1.8 mu m; the vertical axis aberration diagram is shown in detail in fig. 6, and it can be seen that the aberration is small.

In this embodiment, the focal length f of the optical imaging lens is 10.43 mm; the f-number FNO is 2.0; the distance TTL between the object side surface 11 of the first lens element 1 and the imaging surface 9 on the optical axis I is 20.79 mm; the field angle FOV is 36 °, and the image plane diameter Φ is 6.8 mm.

Example two

As shown in fig. 7, in this embodiment, the surface-type convexo-concave and the refractive index of each lens element are substantially the same as those of the first embodiment, only the image-side surface 12 of the first lens element 1 is a concave surface, and the optical parameters such as the curvature radius of each lens element surface and the lens thickness are different.

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

TABLE 2-1 detailed optical data for example two

For the detailed data of the parameters of each aspheric surface of this embodiment, refer to the following table:

The MTF transfer function curve chart of the specific embodiment is shown in detail in FIG. 8, and it can be seen that the image resolution is good, the resolution is high, the resolution reaches 280lp/mm which is more than 0.3, and the imaging quality is good; the defocusing curve graph at the temperature of 60 ℃ is shown in detail in fig. 9, fig. 9 is a temperature-drift defocusing curve graph under a single lens, if a holder (base) and a Barrel (frame) are matched, the defocusing can basically reach 0 degree, and the back focus is basically unchanged under the conditions of high temperature and low temperature; the field curvature and distortion diagram are shown in detail in (a) and (B) of fig. 10, and it can be seen that the field curvature is extremely small; the distortion is small, and the optical distortion is less than 0.5%; the vertical axis chromatic aberration diagram is detailed in a figure 11, and the chromatic aberration is small and is less than 1.8 mu m; the vertical axis aberration diagram is shown in detail in fig. 12, and it can be seen that the aberration is small.

In this embodiment, the focal length f of the optical imaging lens is 10.45 mm; the f-number FNO is 2.0; the distance TTL between the object side surface 11 of the first lens element 1 and the imaging surface 9 on the optical axis I is 20.78 mm; the field angle FOV is 36 °, and the image plane diameter Φ is 6.8 mm.

EXAMPLE III

As shown in fig. 13, in this embodiment, the surface-type convexo-concave and the refractive index of each lens element are substantially the same as those of the first embodiment, only the image-side surface 12 of the first lens element 1 is a concave surface, and the optical parameters such as the curvature radius of each lens element surface and the lens thickness are different.

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 curve chart of the specific embodiment is shown in detail in FIG. 14, and it can be seen that the image resolution is good, the resolution is high, the resolution reaches 280lp/mm which is more than 0.3, and the imaging quality is good; the defocusing curve graph at the temperature of 60 ℃ is shown in detail in fig. 15, fig. 15 is a temperature-drift defocusing curve graph under a single lens, if a holder (base) and a Barrel (frame) are matched, the defocusing can basically reach 0 degree, and the back focus is basically unchanged under the conditions of high temperature and low temperature; the field curvature and distortion map are shown in detail in (a) and (B) of fig. 16, and it can be seen that the field curvature is extremely small; the distortion is small, and the optical distortion is less than 0.5%; the vertical axis chromatic aberration diagram is detailed in a figure 17, and the chromatic aberration is small and is less than 1.8 mu m; the vertical axis aberration diagram is shown in detail in fig. 18, and it can be seen that the aberration is small.

In this embodiment, the focal length f of the optical imaging lens is 10.45 mm; the f-number FNO is 2.0; the distance TTL between the object side surface 11 of the first lens element 1 and the imaging surface 9 on the optical axis I is 20.79 mm; the field angle FOV is 36 °, and the image plane diameter Φ is 6.8 mm.

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. An optical imaging lens characterized in that: the lens comprises a first lens, a second lens, a third lens, a fourth lens, a fifth lens and a fourth lens, wherein the first lens, the second lens and the fifth lens are arranged in sequence from the object side to the image side along an optical axis; the first lens element to the fifth lens element respectively comprise an object side surface facing the object side and allowing the imaging light to pass and an image side surface facing the image side and allowing the imaging light to pass;

the optical imaging lens only has the five lenses with the refractive indexes.

2. The optical imaging lens according to claim 1, characterized in that: and the diaphragm is arranged between the second lens and the third lens.

3. The optical imaging lens of claim 1, further satisfying: vd4>50, wherein vd4 is the d-line abbe number of the fourth lens.

4. The optical imaging lens according to claim 1, characterized in that: the first lens is made of H-LAF52 glass material.

5. The optical imaging lens of claim 1, further satisfying: t1 < 3mm, T2<1mm, T3<1mm, T4<5mm, and T5<1.2mm, wherein T1 is a central thickness of the first lens on the optical axis, T2 is a central thickness of the second lens on the optical axis, T3 is a central thickness of the third lens on the optical axis, T4 is a central thickness of the fourth lens on the optical axis, and T5 is a central thickness of the fifth lens on the optical axis.

6. The optical imaging lens of claim 1, further satisfying: ALT <11mm, wherein ALT is a sum of five lens thicknesses of the first lens to the fifth lens on the optical axis.

7. The optical imaging lens of claim 1, further satisfying: ALG <10.5mm, wherein ALG is the sum of air gaps between the first lens and an imaging surface on the optical axis.

8. The optical imaging lens of claim 1, further satisfying: ALT/ALG <1.5, wherein ALT is the sum of five lens thicknesses of the first lens to the fifth lens on the optical axis, and ALG is the sum of air gaps between the first lens and an imaging surface on the optical axis.