CN113093373B

CN113093373B - Optical imaging lens group

Info

Publication number: CN113093373B
Application number: CN202110426995.8A
Authority: CN
Inventors: 陈超; 计云兵; 戴付建; 赵烈烽
Original assignee: Zhejiang Sunny Optics Co Ltd
Current assignee: Zhejiang Sunny Optics Co Ltd
Priority date: 2021-04-20
Filing date: 2021-04-20
Publication date: 2023-02-24
Anticipated expiration: 2041-04-20
Also published as: CN113093373A

Abstract

The invention provides an optical imaging lens group. The optical imaging lens group sequentially comprises from an object side to an image side along an optical axis: a first lens having a positive refractive power; a second lens having a negative focal power; a third lens; a fourth lens having a positive refractive power; wherein, satisfy between the on-axis distance TTL of the imaging surface of the object side face to optical imaging lens group and the effective focal length f of optical imaging lens group of first lens: TTL/f <1.0. The invention solves the problem of poor imaging quality of the optical imaging lens group in the prior art.

Description

Optical imaging lens group

Technical Field

The invention relates to the technical field of optical imaging equipment, in particular to an optical imaging lens group.

Background

The telephoto lens has a long focal length, a small viewing angle, and a large image on the negative film. Suitable for photographing distant objects. Because the depth of field range of the camera is smaller than that of a standard lens, the camera can more effectively blur the background to highlight the focusing main body, the shot main body is generally far away from the camera, the deformation in the perspective aspect of the portrait is smaller, and the shot portrait is more vivid.

The long-focus shooting is more stable, but the traditional telescopic lens has the problem of unstable shooting. In addition, the use of the telescopic zoom lens affects the thickness and reliability of the body, so the inner zoom is the best way for the mobile phone to realize the optical zoom. In order to realize zooming in an ultrathin fuselage, a telephoto lens gradually adopts a periscopic structure, but the current telephoto lens has a problem of poor imaging quality.

That is, the optical imaging lens group in the prior art has the problem of poor imaging quality.

Disclosure of Invention

The invention mainly aims to provide an optical imaging lens group to solve the problem of poor imaging quality of the optical imaging lens group in the prior art.

To achieve the above object, according to one aspect of the present invention, there is provided an optical imaging lens group comprising, in order from an object side to an image side along an optical axis: a first lens having a positive refractive power; a second lens having a negative focal power; a third lens; a fourth lens having a positive refractive power; wherein, satisfy between the on-axis distance TTL of the imaging plane of the object side face to optical imaging lens group of first lens and the effective focal length f of optical imaging lens group: TTL/f <1.0.

Further, the effective focal length f of the optical imaging lens group, the effective focal length f1 of the first lens and the effective focal length f2 of the second lens satisfy: 4.0 ≦ f/f1| + | f/f2| ≦ 5.0.

Further, the center thickness CT3 of the third lens on the optical axis, and the air interval T34 of the third lens and the fourth lens on the optical axis satisfy: 0.5 ≦ T34/CT3 ≦ 2.5.

Further, the effective focal length f2 of the second lens, the curvature radius R3 of the object side surface of the second lens, and the curvature radius R4 of the image side surface of the second lens satisfy: 0.5 | (R3 + R4)/f 2| ≦ 1.5.

Further, the effective focal length f1 of the first lens, the curvature radius R4 of the image side surface of the second lens and the curvature radius R5 of the object side surface of the third lens satisfy: 0 ≦ (R4 + R5)/f 1 ≦ 2.0.

Further, a center thickness CT1 of the first lens on the optical axis, a center thickness CT2 of the second lens on the optical axis, a center thickness CT3 of the third lens on the optical axis, a center thickness CT4 of the fourth lens on the optical axis, and an air interval T12 of the first lens and the second lens on the optical axis satisfy: 0.5 ≦ (CT 1+ CT2+ T12)/(CT 3+ CT 4) ≦ 1.2.

Further, the combined focal length f234 of the second lens, the third lens and the fourth lens and the effective focal length f2 of the second lens satisfy: 0.5 ≦ f234/f2 ≦ 1.2.

Further, an on-axis distance TTL from the object side surface of the first lens to the imaging surface of the optical imaging lens group and a distance SD from the diaphragm of the optical imaging lens group to the image side surface of the fourth lens satisfy: TTL/SD is less than or equal to 2.0 and less than or equal to 4.2.

Further, the distance BFL between the image side surface of the fourth lens and the imaging surface of the optical imaging lens group on the optical axis and the sum sigma CT of the central thicknesses of all the lenses on the optical axis satisfy that: 2.0 ≦ BFL/Σ CT ≦ 3.5.

Further, the effective focal length f1 of the first lens and the effective focal length f2 of the second lens satisfy: f1/f4 is 0.6.

According to another aspect of the present invention, there is provided an optical imaging lens group, comprising in order from an object side to an image side along an optical axis: a first lens having a positive refractive power; a second lens, an object side surface of the second lens being a convex surface; a third lens element, an object-side surface of the third lens element being convex; a fourth lens having a positive refractive power; wherein, satisfy between the on-axis distance TTL of the imaging plane of the object side face to optical imaging lens group of first lens and the effective focal length f of optical imaging lens group: TTL/f <1.0.

Further, the effective focal length f2 of the second lens, the radius of curvature R3 of the object-side surface of the second lens, and the radius of curvature R4 of the image-side surface of the second lens satisfy: 0.5 | (R3 + R4)/f 2| ≦ 1.5.

Further, the effective focal length f1 of the first lens, the curvature radius R4 of the image side surface of the second lens, and the curvature radius R5 of the object side surface of the third lens satisfy: 0 ≦ (R4 + R5)/f 1 ≦ 2.0.

Further, the combined focal length f234 of the second lens, the third lens and the fourth lens and the effective focal length f2 of the second lens satisfy the following condition: 0.5 ≦ f234/f2 ≦ 1.2.

Further, an on-axis distance TTL from the object side surface of the first lens to the imaging surface of the optical imaging lens group and a distance SD from the diaphragm of the optical imaging lens group to the image side surface of the fourth lens satisfy: 2.0 ≦ TTL/SD ≦ 4.2.

Further, the effective focal length f1 of the first lens and the effective focal length f2 of the second lens satisfy: f1/f4 is 0 to 0.6.

By applying the technical scheme of the invention, the optical imaging lens group sequentially comprises a first lens, a second lens, a third lens and a fourth lens from an object side to an image side along an optical axis, wherein the first lens has positive focal power; the second lens has negative focal power; the fourth lens has positive focal power; wherein, satisfy between the on-axis distance TTL of the imaging surface of the object side face to optical imaging lens group and the effective focal length f of optical imaging lens group of first lens: TTL/f <1.0.

Through the reasonable distribution of the focal power of each lens, the aberration generated by the optical imaging lens group is favorably balanced, and the imaging quality of the optical imaging lens group is greatly improved. The range of the ratio of the axial distance TTL from the object side surface of the first lens to the imaging surface of the optical imaging lens group to the effective focal length f of the optical imaging lens group is limited, so that the realization of a shorter total optical length TTL is facilitated while a larger effective focal length is realized, and better resolving power can still be ensured during long-distance shooting.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:

fig. 1 is a schematic view showing a configuration of an optical imaging lens group according to a first example of the present invention;

fig. 2 to 4 respectively show an on-axis chromatic aberration curve, an astigmatism curve, and a distortion curve of the optical imaging lens group in fig. 1;

fig. 5 is a schematic view showing a configuration of an optical imaging lens group according to a second example of the present invention;

fig. 6 to 8 show an on-axis chromatic aberration curve, an astigmatism curve, and a distortion curve of the optical imaging lens group in fig. 5, respectively;

fig. 9 is a schematic view showing a configuration of an optical imaging lens group according to a third example of the present invention;

fig. 10 to 12 show an on-axis chromatic aberration curve, an astigmatism curve, and a distortion curve of the optical imaging lens group in fig. 9, respectively;

fig. 13 is a schematic view showing a configuration of an optical imaging lens group of example four of the present invention;

fig. 14 to 16 show an on-axis chromatic aberration curve, an astigmatism curve, and a distortion curve of the optical imaging lens group in fig. 13, respectively;

fig. 17 is a schematic view showing a configuration of an optical imaging lens group of example five of the present invention;

fig. 18 to 20 show an on-axis chromatic aberration curve, an astigmatism curve, and a distortion curve of the optical imaging lens group in fig. 17, respectively;

fig. 21 is a schematic view showing a configuration of an optical imaging lens group of example six of the present invention;

fig. 22 to 24 respectively show an on-axis chromatic aberration curve, an astigmatism curve, and a distortion curve of the optical imaging lens group in fig. 21;

fig. 25 is a schematic view showing a structure of an optical imaging lens group of example seven of the present invention;

fig. 26 to 28 show an on-axis chromatic aberration curve, an astigmatism curve, and a distortion curve of the optical imaging lens group in fig. 25, respectively.

Fig. 29 is a schematic view showing a configuration of an optical imaging lens group of example eight of the present invention;

fig. 30 to 32 show an on-axis chromatic aberration curve, an astigmatism curve, and a distortion curve of the optical imaging lens group in fig. 29, respectively.

Wherein the figures include the following reference numerals:

STO, stop; e1, a first lens; s1, an object side surface of a first lens; s2, an image side surface of the first lens; e2, a second lens; s3, an object side surface of the second lens; s4, an image side surface of the second lens; e3, a third lens; s5, an object side surface of the third lens; s6, the image side surface of the third lens; e4, a fourth lens; s7, an object side surface of the fourth lens; s8, an image side surface of the fourth lens; e5, an optical filter; s9, the object side surface of the optical filter; s10, an image side surface of the optical filter; s11, imaging surface.

Detailed Description

It should be noted that, in the present application, the embodiments and features of the embodiments may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.

It is to be noted that, unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

In the present invention, unless specified to the contrary, use of the terms of orientation such as "upper, lower, top, bottom" or the like, generally refer to the orientation as shown in the drawings, or to the component itself in a vertical, perpendicular, or gravitational orientation; likewise, for ease of understanding and description, "inner and outer" refer to the inner and outer relative to the profile of the components themselves, but the above directional words are not intended to limit the invention.

It should be noted that in this specification the expressions first, second, third etc. are only used 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.

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 close to the object side becomes the object side surface of the lens, and the surface of each lens close to the image side is called the image side surface of the lens. The determination of the surface shape in the paraxial region can be performed by determining whether the surface shape is concave or convex based on the R value (R denotes the radius of curvature of the paraxial region, and usually denotes the R value in the lens database (lens data) in the optical software) according to the determination method of a person ordinarily skilled in the art. Regarding the object side, when the R value is positive, the object side is judged to be convex, and when the R value is negative, the object side is judged to be concave; in the case of the image side surface, the image side surface is determined to be concave when the R value is positive, and is determined to be convex when the R value is negative.

The invention provides an optical imaging lens group, aiming at solving the problem of poor imaging quality of the optical imaging lens group in the prior art.

Example one

As shown in fig. 1 to 32, the optical imaging lens group includes, in order from an object side to an image side along an optical axis, a first lens, a second lens, a third lens, and a fourth lens, the first lens having positive power; the second lens has negative focal power; the fourth lens has positive focal power; wherein, satisfy between the on-axis distance TTL of the imaging plane of the object side face to optical imaging lens group of first lens and the effective focal length f of optical imaging lens group: TTL/f <1.0.

Preferably, an on-axis distance TTL from the object side surface of the first lens to the imaging surface of the optical imaging lens group and an effective focal length f of the optical imaging lens group satisfy: 0.8 and then ttl/f is less than 0.9.

In the present embodiment, the effective focal length f of the optical imaging lens group, the effective focal length f1 of the first lens, and the effective focal length f2 of the second lens satisfy: 4.0 ≦ f/f1| + | f/f2| ≦ 5.0. By limiting the ranges of the effective focal length f of the optical imaging lens group, the effective focal length f1 of the first lens and the effective focal length f2 of the second lens, the reasonable distribution of focal power of each lens can be ensured, and the realization of small aberration of an optical system is facilitated. Preferably, 4.0 ≦ f/f1| + | f/f2| ≦ 4.5.

In the present embodiment, the center thickness CT3 of the third lens on the optical axis, and the air interval T34 of the third lens and the fourth lens on the optical axis satisfy: 0.5 ≦ T34/CT3 ≦ 2.5. The arrangement is favorable for slowing down light deflection, adjusting the field curvature of the whole optical system, reducing the sensitivity and further obtaining better imaging quality. Preferably, 0.8 ≦ T34/CT3 ≦ 2.5.

In the present embodiment, the effective focal length f2 of the second lens, the radius of curvature R3 of the object-side surface of the second lens, and the radius of curvature R4 of the image-side surface of the second lens satisfy: 0.5 ≦ (R3 + R4)/f 2| ≦ 1.5. The arrangement is favorable for controlling the incident angle of the light rays of the off-axis field of view on the image plane, and the matching performance of the light rays with the photosensitive element and the band-pass filter is improved. Preferably, 0.7 | (R3 + R4)/f 2| ≦ 1.3.

In the present embodiment, the effective focal length f1 of the first lens, the radius of curvature R4 of the image-side surface of the second lens, and the radius of curvature R5 of the object-side surface of the third lens satisfy: 0 ≦ (R4 + R5)/f 1 ≦ 2.0. By limiting the relationship among the effective focal length f1 of the first lens, the radius of curvature R4 of the image-side surface of the second lens, and the radius of curvature R5 of the object-side surface of the third lens, optical distortion can be reduced, ensuring better imaging quality. Preferably, 0.7 ≦ (R4 + R5)/f 1 ≦ 1.8.

In the present embodiment, the central thickness CT1 of the first lens on the optical axis, the central thickness CT2 of the second lens on the optical axis, the central thickness CT3 of the third lens on the optical axis, the central thickness CT4 of the fourth lens on the optical axis, and the air interval T12 of the first lens and the second lens on the optical axis satisfy: 0.5 ≦ (CT 1+ CT2+ T12)/(CT 3+ CT 4) ≦ 1.2. By limiting the relation among the central thickness CT1 of the first lens on the optical axis, the central thickness CT2 of the second lens on the optical axis, the central thickness CT3 of the third lens on the optical axis, the central thickness CT4 of the fourth lens on the optical axis and the air interval T12 of the first lens and the second lens on the optical axis, the optical lens can be ensured to have good processing characteristics, and the processing and manufacturing of each lens are facilitated. Preferably, 0.7 ≦ (CT 1+ CT2+ T12)/(CT 3+ CT 4) ≦ 1.2.

In the present embodiment, the combined focal length f234 of the second lens, the third lens and the fourth lens, and the effective focal length f2 of the second lens satisfy: 0.5 ≦ f234/f2 ≦ 1.2. By controlling the effective focal length of the second lens and the optical system, chromatic aberration is facilitated to be improved. Preferably, 0.5 ≦ f234/f2 ≦ 1.15.

In this embodiment, an on-axis distance TTL from the object side surface of the first lens to the imaging surface of the optical imaging lens group and a distance SD from the stop of the optical imaging lens group to the image side surface of the fourth lens satisfy: 2.0 ≦ TTL/SD ≦ 4.2. The arrangement can reduce the processing difficulty and simultaneously ensure that the assembly of the optical imaging lens group has higher stability. Preferably, 2.7 ≦ TTL/SD ≦ 4.1.

In this embodiment, a distance BFL on the optical axis from the image-side surface of the fourth lens to the imaging surface of the optical imaging lens group, and a sum Σ CT of center thicknesses of all lenses on the optical axis satisfy: 2.0 ≦ BFL/Σ CT ≦ 3.5. The reasonable size distribution ensures that the optical imaging lens group has longer back focus. Preferably, 2.2 ≦ BFL/Σ CT ≦ 3.5.

In the present embodiment, the effective focal length f1 of the first lens and the effective focal length f4 of the fourth lens satisfy: f1/f4 is 0.6. The focal power of the first lens and the focal power of the fourth lens are reasonably controlled, the optical sensitivity of the first lens and the optical sensitivity of the fourth lens are effectively reduced, and the mass production is more favorably realized. Preferably, 0.2 ≦ f1/f4 ≦ 0.55.

Example two

As shown in fig. 1 to 32, the optical imaging lens group includes, in order from an object side to an image side along an optical axis, a first lens, a second lens, a third lens, and a fourth lens, the first lens having positive power; the object side surface of the second lens is a convex surface; the object side surface of the third lens is a convex surface; the fourth lens has positive focal power; wherein, satisfy between the on-axis distance TTL of the imaging plane of the object side face to optical imaging lens group of first lens and the effective focal length f of optical imaging lens group: TTL/f <1.0.

By reasonably distributing the surface type and focal power of each lens, the tolerance sensitivity of each lens is reduced, the aberration of the optical imaging lens group is reduced, and the optical imaging lens group is ensured to have higher imaging quality. The range of the ratio of the axial distance TTL from the object side surface of the first lens to the imaging surface of the optical imaging lens group to the effective focal length f of the optical imaging lens group is limited, so that the realization of a shorter total optical length TTL is facilitated while a larger effective focal length is realized, and better resolving power can be still obtained during long-distance shooting.

Preferably, an on-axis distance TTL from the object side surface of the first lens to the imaging surface of the optical imaging lens group and an effective focal length f of the optical imaging lens group satisfy: 0.8 and woven ttl/f <0.9.

In the present embodiment, the central thickness CT1 of the first lens on the optical axis, the central thickness CT2 of the second lens on the optical axis, the central thickness CT3 of the third lens on the optical axis, the central thickness CT4 of the fourth lens on the optical axis, and the air interval T12 of the first lens and the second lens on the optical axis satisfy: 0.5 ≦ (CT 1+ CT2+ T12)/(CT 3+ CT 4) ≦ 1.2. The optical lens can be ensured to have good processing characteristics by limiting the relationship among the central thickness CT1 of the first lens on the optical axis, the central thickness CT2 of the second lens on the optical axis, the central thickness CT3 of the third lens on the optical axis, the central thickness CT4 of the fourth lens on the optical axis and the air interval T12 of the first lens and the second lens on the optical axis, and is convenient for processing and manufacturing each lens. Preferably, 0.7 ≦ (CT 1+ CT2+ T12)/(CT 3+ CT 4) ≦ 1.2.

In this embodiment, an on-axis distance TTL from the object side surface of the first lens to the imaging surface of the optical imaging lens group and a distance SD from the stop of the optical imaging lens group to the image side surface of the fourth lens satisfy: TTL/SD is less than or equal to 2.0 and less than or equal to 4.2. The arrangement can reduce the processing difficulty and simultaneously ensure that the assembly of the optical imaging lens group has higher stability. Preferably, 2.7 ≦ TTL/SD ≦ 4.1.

In this embodiment, a distance BFL on the optical axis from the image-side surface of the fourth lens to the imaging surface of the optical imaging lens group, and a sum Σ CT of center thicknesses of all lenses on the optical axis satisfy: 2.0 ≦ BFL/Σ CT ≦ 3.5. Reasonable size layout ensures that the optical imaging lens group has longer back focus. Preferably, 2.2 ≦ BFL/Σ CT ≦ 3.5.

In the present embodiment, the effective focal length f1 of the first lens and the effective focal length f4 of the fourth lens satisfy: f1/f4 is 0 to 0.6. The focal power of the first lens and the focal power of the fourth lens are reasonably controlled, the optical sensitivity of the first lens and the optical sensitivity of the fourth lens are effectively reduced, and the mass production is more favorably realized. Preferably, 0.2 ≦ f1/f4 ≦ 0.55.

Optionally, the optical imaging lens group may further include a filter for correcting color deviation and/or a protective glass for protecting the photosensitive element on the imaging surface.

The optical imaging lens group in the present application may employ a plurality of lenses, for example, the above four lenses. By reasonably distributing the focal power, the surface shape, the central thickness of each lens, the axial distance between each lens and the like, the aperture of the optical imaging lens group can be effectively increased, the sensitivity of the lens can be reduced, and the machinability of the lens can be improved, so that the optical imaging lens group is more beneficial to production and processing and can be suitable for portable electronic equipment such as a smart phone. The optical imaging lens group also has large aperture and large field angle. The advantages of ultra-thin and good imaging quality can meet the miniaturization requirement of intelligent electronic products.

In the present application, at least one of the mirror surfaces of each lens 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 during imaging can be eliminated as much as possible, thereby improving the imaging quality.

However, it will be appreciated by those skilled in the art that the number of lenses constituting the optical imaging lens group can be varied to achieve the various results and advantages described in the present specification without departing from the claimed subject matter. For example, although the description has been made taking four lenses as an example in the embodiment, the optical imaging lens group is not limited to include four lenses. The optical imaging lens group may also include other numbers of lenses, as desired.

Specific surface types, parameters of the optical imaging lens group applicable to the above embodiments are further described below with reference to the drawings.

It should be noted that any one of the following examples one to eight is applicable to all embodiments of the present application.

Example one

As shown in fig. 1 to 4, an optical imaging lens group of a first example of the present application is described, and fig. 1 shows a schematic structural view of the optical imaging lens group of the first example.

As shown in fig. 1, the optical imaging lens assembly, in order from an object side to an image side, comprises: stop STO, first lens E1, second lens E2, third lens E3, fourth lens E4, filter E5, and image plane S11.

The first lens element E1 has positive refractive power, and the object-side surface S1 and the image-side surface S2 of the first lens element are convex and concave, respectively. The second lens element E2 has negative refractive power, and the object-side surface S3 and the image-side surface S4 thereof are convex and concave, respectively. The third lens element E3 has negative refractive power, and the object-side surface S5 and the image-side surface S6 of the third lens element are convex and concave, respectively. The fourth lens element E4 has positive refractive power, and the object-side surface S7 and the image-side surface S8 of the fourth lens element are convex, respectively. The filter E5 has an object side surface S9 of the filter and an image side surface S10 of the filter. The light from the object passes through the respective surfaces S1 to S10 in order and is finally imaged on the imaging plane S11.

In this example, the total effective focal length f of the optical imaging lens group is 26.99mm, and the maximum half field angle FOV of the optical imaging lens group is 6.11 ° and Fno of the optical imaging lens group is 4.15.

Table 1 shows a basic structural parameter table of an optical imaging lens group of example one, in which the units of the radius of curvature, thickness/distance, and focal length are millimeters (mm).

TABLE 1

In example one, the object-side surface and the image-side surface of any one of the first lens element E1 to the fourth lens element E4 are aspheric surfaces, and the surface shape of each aspheric surface lens can be defined by, but not limited to, the following aspheric surface formula:

wherein x is the distance rise from the vertex of the aspheric surface 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 aspherical surface. Table 2 below gives the coefficients A4, A6, A8, A10 of the higher order terms that can be used for each of the aspherical mirror surfaces S5-S8 in example one.

Flour mark	A4	A6	A8	A10
					S5	-1.6019E-03	-1.0506E-04	-7.4381E-06	0.0000E+00
S6	-2.1443E-03	-2.2961E-04	-4.2817E-05	0.0000E+00
					S7	4.7466E-04	3.7707E-04	-9.2452E-05	7.7123E-06
S8	-9.9270E-04	2.4869E-04	-7.4299E-05	5.3934E-06

TABLE 2

Fig. 2 shows on-axis chromatic aberration curves of the optical imaging lens group of example one, which represent the deviation of the convergent focus of light rays of different wavelengths after passing through the optical imaging lens group. Fig. 3 shows astigmatism curves of the optical imaging lens group of the first example, which represent meridional field curvature and sagittal field curvature. Fig. 4 shows distortion curves of the optical imaging lens group of example one, which represent distortion magnitude values corresponding to different angles of view.

As can be seen from fig. 2 to 4, the optical imaging lens assembly of the first example can achieve good imaging quality.

Example two

As shown in fig. 5 to 8, an optical imaging lens group of example two of the present application is described. In this example and the following examples, descriptions of parts similar to example two will be omitted for the sake of brevity. Fig. 5 shows a schematic view of the optical imaging lens group of example two.

As shown in fig. 5, the optical imaging lens assembly, in order from an object side to an image side, comprises: stop STO, first lens E1, second lens E2, third lens E3, fourth lens E4, filter E5, and image plane S11.

The first lens element E1 has positive refractive power, and the object-side surface S1 and the image-side surface S2 of the first lens element are convex and concave, respectively. The second lens element E2 has negative refractive power, and the object-side surface S3 and the image-side surface S4 of the second lens element are convex and concave, respectively. The third lens element E3 has negative refractive power, and the object-side surface S5 and the image-side surface S6 of the third lens element are convex and concave, respectively. The fourth lens element E4 has positive refractive power, and the object-side surface S7 and the image-side surface S8 of the fourth lens element are convex. The filter E5 has an object side surface S9 of the filter and an image side surface S10 of the filter. The light from the object passes through the respective surfaces S1 to S10 in order and is finally imaged on the imaging plane S11.

In this example, the total effective focal length f of the optical imaging lens group is 26.99mm, and the maximum half field angle FOV of the optical imaging lens group is 6.12 ° and Fno of the optical imaging lens group is 4.15.

Table 3 shows a basic structural parameter table of the optical imaging lens group of example two, in which the units of the radius of curvature, thickness/distance, and focal length are millimeters (mm).

TABLE 3

Table 4 shows the high-order term coefficients that can be used for each aspherical mirror surface in example two, wherein each aspherical mirror surface type can be defined by formula (1) given in example two above.

Flour mark	A4	A6	A8	A10
					S5	-1.7893E-03	-1.1466E-04	-9.2100E-06	0.0000E+00
S6	-2.7058E-03	-3.2368E-04	-4.0632E-05	0.0000E+00
					S7	1.6726E-04	1.4995E-04	-6.4341E-05	6.8410E-06
S8	-5.8424E-04	1.5201E-04	-6.5983E-05	6.6284E-06

TABLE 4

Fig. 6 shows an on-axis chromatic aberration curve of the optical imaging lens group of example two, which represents a convergent focus deviation of light rays of different wavelengths after passing through the optical imaging lens group. Fig. 7 shows astigmatism curves of the optical imaging lens group of example two, which represent meridional field curvature and sagittal field curvature. Fig. 8 shows distortion curves of the optical imaging lens group of example two, which represent distortion magnitude values corresponding to different angles of view.

As can be seen from fig. 6 to 8, the optical imaging lens group given in example two can achieve good imaging quality.

EXAMPLE III

As shown in fig. 9 to 12, an optical imaging lens group of example three of the present application is described. In this example and the following examples, descriptions of parts similar to example three will be omitted for the sake of brevity. Fig. 9 shows a structural diagram of an optical imaging lens group of example three.

As shown in fig. 9, the optical imaging lens assembly includes, in order from an object side to an image side: a stop STO, a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a filter E5, and an image plane S11.

The first lens element E1 has positive refractive power, and the object-side surface S1 and the image-side surface S2 of the first lens element are convex and concave, respectively. The second lens element E2 has negative refractive power, and the object-side surface S3 and the image-side surface S4 of the second lens element are convex and concave, respectively. The third lens element E3 has negative refractive power, and the object-side surface S5 and the image-side surface S6 of the third lens element are convex and concave, respectively. The fourth lens element E4 has positive refractive power, and the object-side surface S7 and the image-side surface S8 of the fourth lens element are convex, respectively. The filter E5 has an object side surface S9 of the filter and an image side surface S10 of the filter. The light from the object passes through the respective surfaces S1 to S10 in order and is finally imaged on the imaging plane S11.

In this example, the total effective focal length f of the optical imaging lens group is 26.99mm, and the maximum half field angle FOV of the optical imaging lens group is 6.13 ° and Fno of the optical imaging lens group is 3.90.

Table 5 shows a basic structural parameter table of the optical imaging lens group of example three, in which the units of the radius of curvature, thickness/distance, and focal length are all millimeters (mm).

TABLE 5

Table 6 shows the high-order term coefficients that can be used for each aspherical mirror surface in example three, wherein each aspherical mirror surface type can be defined by formula (1) given in example three above.

Flour mark	A4	A6	A8	A10
					S5	-2.0386E-03	-1.4254E-04	-8.4158E-06	0.0000E+00
S6	-3.0186E-03	-4.0149E-04	-2.4811E-05	0.0000E+00
					S7	8.3003E-05	-3.2321E-06	-3.0269E-05	3.8359E-06
S8	-5.2153E-04	1.3540E-05	-3.3594E-05	3.7871E-06

TABLE 6

Fig. 10 shows on-axis chromatic aberration curves of the optical imaging lens group of example three, which represent the convergent focus deviations of light rays of different wavelengths after passing through the optical imaging lens group. Fig. 11 shows astigmatism curves of the optical imaging lens group of example three, which represent meridional field curvature and sagittal field curvature. Fig. 12 shows distortion curves of the optical imaging lens group of example three, which represent distortion magnitude values corresponding to different angles of view.

As can be seen from fig. 10 to 12, the optical imaging lens group given in example three can achieve good imaging quality.

Example four

As shown in fig. 13 to 16, an optical imaging lens group of example four of the present application is described. In this and the following examples, a description of portions similar to example four will be omitted for the sake of brevity. Fig. 13 shows a schematic view of the optical imaging lens group of example four.

As shown in fig. 13, the optical imaging lens assembly, in order from an object side to an image side, comprises: stop STO, first lens E1, second lens E2, third lens E3, fourth lens E4, filter E5, and image plane S11.

The first lens element E1 has positive refractive power, and the object-side surface S1 and the image-side surface S2 of the first lens element are convex. The second lens element E2 has negative refractive power, and the object-side surface S3 and the image-side surface S4 of the second lens element are convex and concave, respectively. The third lens element E3 has negative refractive power, and the object-side surface S5 and the image-side surface S6 of the third lens element are convex and concave, respectively. The fourth lens element E4 has positive refractive power, and the object-side surface S7 and the image-side surface S8 of the fourth lens element are convex. The filter E5 has an object side surface S9 of the filter and an image side surface S10 of the filter. The light from the object passes through the respective surfaces S1 to S10 in order and is finally imaged on the imaging plane S11.

In this example, the total effective focal length f of the optical imaging lens group is 27.01mm, and the maximum half field angle FOV of the optical imaging lens group is 6.11 ° and Fno of the optical imaging lens group is 4.16.

Table 7 shows a basic structural parameter table of the optical imaging lens group of example four, in which the units of the radius of curvature, thickness/distance, and focal length are all millimeters (mm).

TABLE 7

Table 8 shows the high-order term coefficients that can be used for each aspherical mirror surface in example four, wherein each aspherical mirror surface type can be defined by formula (1) given in example four above.

Flour mark	A4	A6	A8	A10
					S5	-2.5724E-03	-8.4059E-05	1.5908E-06	0.0000E+00
S6	-2.3319E-03	-1.4013E-04	1.4963E-05	0.0000E+00
					S7	1.7603E-03	-2.9137E-05	2.8887E-05	2.4601E-07
S8	9.4865E-04	4.7840E-07	1.3992E-05	1.6492E-06

TABLE 8

Fig. 14 shows on-axis chromatic aberration curves of the optical imaging lens group of example four, which represent convergent focus deviations of light rays of different wavelengths after passing through the optical imaging lens group. Fig. 15 shows astigmatism curves of the optical imaging lens group of example four, which represent meridional field curvature and sagittal field curvature. Fig. 16 shows distortion curves of the optical imaging lens group of example four, which represent distortion magnitude values corresponding to different angles of view.

As can be seen from fig. 14 to 16, the optical imaging lens group given in example four can achieve good imaging quality.

Example five

As shown in fig. 17 to 20, an optical imaging lens group of example five of the present application is described. In this example and the following examples, descriptions of parts similar to example five will be omitted for the sake of brevity. Fig. 17 shows a schematic view of the optical imaging lens group structure of example five.

As shown in fig. 17, the optical imaging lens assembly, in order from an object side to an image side, comprises: stop STO, first lens E1, second lens E2, third lens E3, fourth lens E4, filter E5, and image plane S11.

The first lens element E1 has positive refractive power, and the object-side surface S1 and the image-side surface S2 of the first lens element are convex. The second lens element E2 has negative refractive power, and the object-side surface S3 and the image-side surface S4 of the second lens element are convex and concave, respectively. The third lens element E3 has negative refractive power, and the object-side surface S5 and the image-side surface S6 thereof are convex and concave, respectively. The fourth lens element E4 has positive refractive power, and the object-side surface S7 of the fourth lens element is concave and the image-side surface S8 of the fourth lens element is convex. The filter E5 has an object side surface S9 of the filter and an image side surface S10 of the filter. The light from the object passes through the respective surfaces S1 to S10 in order and is finally imaged on the imaging plane S11.

Table 9 shows a basic structural parameter table of the optical imaging lens group of example five, in which the units of the radius of curvature, thickness/distance, and focal length are all millimeters (mm).

TABLE 9

Table 10 shows the high-order term coefficients that can be used for each aspherical mirror in example five, wherein each aspherical mirror type can be defined by formula (1) given in example five above.

Flour mark	A4	A6	A8	A10
					S5	-2.1412E-03	-9.8681E-05	4.7163E-08	0.0000E+00
S6	-1.1857E-03	-1.4764E-04	2.4755E-05	0.0000E+00
					S7	-5.5697E-04	-3.6139E-05	-4.4463E-07	-2.3778E-07
S8	-1.0841E-03	-4.5632E-05	-4.3826E-06	-2.2404E-07

Watch 10

Fig. 18 shows on-axis chromatic aberration curves of the optical imaging lens group of example five, which represent the convergent focus deviations of light rays of different wavelengths after passing through the optical imaging lens group. Fig. 19 shows astigmatism curves of the optical imaging lens group of example five, which represent meridional field curvature and sagittal field curvature. Fig. 20 shows distortion curves of the optical imaging lens group of example five, which represent distortion magnitude values corresponding to different angles of view.

As can be seen from fig. 18 to 20, the optical imaging lens group given in example five can achieve good imaging quality.

Example six

As shown in fig. 21 to 24, an optical imaging lens group of example six of the present application is described. In this example and the following examples, a description of portions similar to example six will be omitted for the sake of brevity. Fig. 21 is a schematic view showing a configuration of an optical imaging lens group of example six.

As shown in fig. 21, the optical imaging lens assembly, in order from an object side to an image side, comprises: a stop STO, a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a filter E5, and an image plane S11.

The first lens element E1 has positive refractive power, and the object-side surface S1 and the image-side surface S2 of the first lens element are convex and concave, respectively. The second lens element E2 has negative refractive power, and the object-side surface S3 and the image-side surface S4 of the second lens element are convex and concave, respectively. The third lens element E3 has negative refractive power, and the object-side surface S5 and the image-side surface S6 thereof are convex and concave, respectively. The fourth lens element E4 has positive refractive power, and the object-side surface S7 of the fourth lens element is concave and the image-side surface S8 of the fourth lens element is convex. The filter E5 has an object side surface S9 of the filter and an image side surface S10 of the filter. The light from the object passes through the respective surfaces S1 to S10 in order and is finally imaged on the imaging plane S11.

Table 11 shows a basic structural parameter table of the optical imaging lens group of example six, in which the units of the radius of curvature, thickness/distance, and focal length are millimeters (mm).

TABLE 11

Table 12 shows the high-order term coefficients that can be used for each aspherical mirror surface in example six, wherein each aspherical mirror surface type can be defined by formula (1) given in example six above.

TABLE 12

Fig. 22 shows an on-axis chromatic aberration curve of an optical imaging lens group of example six, which represents a convergent focus deviation of light rays of different wavelengths after passing through the optical imaging lens group. Fig. 23 shows astigmatism curves of the optical imaging lens group of example six, which represent meridional field curvature and sagittal field curvature. Fig. 24 shows distortion curves of the optical imaging lens group of example six, which represent distortion magnitude values corresponding to different angles of view.

As can be seen from fig. 22 to 24, the optical imaging lens group given in example six can achieve good imaging quality.

Example seven

As shown in fig. 25 to 28, an optical imaging lens group of example seven of the present application is described. In this example and the following examples, a description of portions similar to example seven will be omitted for the sake of brevity. Fig. 25 shows a schematic view of the optical imaging lens group structure of example seven.

As shown in fig. 25, the optical imaging lens assembly, in order from an object side to an image side, comprises: stop STO, first lens E1, second lens E2, third lens E3, fourth lens E4, filter E5, and image plane S11.

The first lens element E1 has positive refractive power, and the object-side surface S1 and the image-side surface S2 of the first lens element are convex and concave, respectively. The second lens element E2 has negative refractive power, and the object-side surface S3 and the image-side surface S4 of the second lens element are convex and concave, respectively. The third lens element E3 has negative refractive power, and the object-side surface S5 and the image-side surface S6 of the third lens element are convex and concave, respectively. The fourth lens element E4 has positive refractive power, and the object-side surface S7 and the image-side surface S8 of the fourth lens element are convex and concave, respectively. The filter E5 has an object side surface S9 of the filter and an image side surface S10 of the filter. The light from the object sequentially passes through the respective surfaces S1 to S10 and is finally imaged on the imaging plane S11.

In this example, the total effective focal length f of the optical imaging lens group is 27mm, and the maximum half field angle FOV of the optical imaging lens group is 6.13 ° and Fno of the optical imaging lens group is 4.15.

Table 13 shows a basic structural parameter table of the optical imaging lens group of example seven, in which the units of the radius of curvature, thickness/distance, and focal length are all millimeters (mm).

Watch 13

Table 14 shows the high-order term coefficients that can be used for each aspherical mirror surface in example seven, wherein each aspherical mirror surface type can be defined by formula (1) given in example seven above.

Flour mark	A4	A6	A8	A10
					S5	-2.3818E-03	-1.5882E-04	-4.1301E-06	0.0000E+00
S6	-3.3905E-03	-3.8120E-04	1.1775E-06	0.0000E+00
					S7	1.6357E-03	-4.0640E-05	2.2624E-05	1.2024E-07
S8	1.2635E-03	-6.3953E-06	1.3387E-05	1.2619E-06

TABLE 14

Fig. 26 shows an on-axis chromatic aberration curve of an optical imaging lens group of example seven, which represents a convergent focus deviation of light rays of different wavelengths after passing through the optical imaging lens group. Fig. 27 shows astigmatism curves of the optical imaging lens group of example seven, which represent meridional field curvature and sagittal field curvature. Fig. 28 shows distortion curves of the optical imaging lens group of example seven, which represent distortion magnitude values corresponding to different angles of view.

As can be seen from fig. 26 to 28, the optical imaging lens group given in example seven can achieve good imaging quality.

Example eight

As shown in fig. 29 to 32, an optical imaging lens group of example eight of the present application is described. In this example and the following examples, descriptions of portions similar to example eight will be omitted for the sake of brevity. Fig. 29 shows a schematic view of an optical imaging lens group configuration of example eight.

As shown in fig. 29, the optical imaging lens assembly, in order from an object side to an image side, comprises: a stop STO, a first lens E1, a second lens E2, a third lens E3, a fourth lens E4, a filter E5, and an image plane S11.

The first lens element E1 has positive refractive power, and the object-side surface S1 and the image-side surface S2 of the first lens element are convex and concave, respectively. The second lens element E2 has negative refractive power, and the object-side surface S3 and the image-side surface S4 thereof are convex and concave, respectively. The third lens element E3 has negative refractive power, and the object-side surface S5 and the image-side surface S6 of the third lens element are convex and concave, respectively. The fourth lens element E4 has positive refractive power, and the object-side surface S7 and the image-side surface S8 of the fourth lens element are convex, respectively. The filter E5 has an object side surface S9 of the filter and an image side surface S10 of the filter. The light from the object sequentially passes through the respective surfaces S1 to S10 and is finally imaged on the imaging plane S11.

In this example, the total effective focal length f of the optical imaging lens group is 26.99mm, and the maximum half field angle FOV of the optical imaging lens group is 6.13 ° and Fno of the optical imaging lens group is 4.15.

Table 15 shows a basic structural parameter table of the optical imaging lens group of example eight in which the units of the radius of curvature, thickness/distance, and focal length are millimeters (mm).

Watch 15

Table 16 shows the high-order term coefficients that can be used for each aspherical mirror surface in example eight, wherein each aspherical mirror surface type can be defined by formula (1) given in example eight above.

Flour mark	A4	A6	A8	A10
					S5	-2.1453E-03	-1.5272E-04	-1.0499E-05	0.0000E+00
S6	-2.7869E-03	-3.9382E-04	-3.8479E-05	0.0000E+00
					S7	1.9312E-04	2.4344E-05	-2.8581E-05	3.5514E-06
S8	-5.6058E-04	3.5177E-05	-3.1522E-05	3.4423E-06

TABLE 16

Fig. 30 shows on-axis chromatic aberration curves of the optical imaging lens group of example eight, which represent convergent focus deviations of light rays of different wavelengths after passing through the optical imaging lens group. Fig. 31 shows astigmatism curves of the optical imaging lens group of example eight, which represent meridional field curvature and sagittal field curvature. Fig. 32 shows distortion curves of the optical imaging lens group of example eight, which represent distortion magnitude values corresponding to different angles of view.

As can be seen from fig. 30 to 32, the optical imaging lens group given in example eight can achieve good imaging quality.

To sum up, examples one to eight satisfy the relationships shown in table 17, respectively.

TABLE 17

Table 18 shows effective focal lengths f, f1 to f4, and maximum half field angles FOV of the optical imaging lens groups of examples one to eight.

Example parameters	1	2	3	4	5	6	7	8
									f	26.99	26.99	26.99	27.01	27.01	26.99	27.00	26.99
f1	12.07	11.65	11.38	9.70	9.68	11.24	10.71	11.20
									f2	-14.69	-13.90	-13.76	-20.93	-19.15	-13.51	-14.44	-13.28
f3	-34.06	-39.02	-37.33	-11.67	-13.40	-38.06	-25.78	-34.97
									f4	22.80	25.75	27.76	28.37	33.76	27.17	29.78	26.25
TTL	24.00	24.00	24.00	24.00	24.00	24.00	24.00	24.00
									ImgH	2.90	2.90	2.90	2.90	2.90	2.90	2.90	2.90
Semi-FOV	6.11	6.12	6.13	6.11	6.11	6.12	6.13	6.13
									Fno	4.15	4.15	3.90	4.16	4.16	4.15	4.15	4.15

Watch 18

The present application also provides an imaging device whose electron photosensitive element may be a photo-coupled device (CCD) or a complementary metal oxide semiconductor device (CMOS). The imaging device may be a stand-alone imaging device such as a digital camera, or may be an imaging module integrated on a mobile electronic device such as a mobile phone. The imaging device is equipped with the optical imaging lens group described above.

It is to be understood that the above-described embodiments are only a few, and not all, embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular is intended to include the plural unless the context clearly dictates otherwise, and it should be further understood that the terms "comprises" and/or "comprising," when used in this specification, specify the presence of features, steps, operations, devices, components, and/or combinations thereof.

It should be noted that the terms "first," "second," and the like in the description and claims of this application and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the application described herein are capable of operation in other sequences than those illustrated or described herein.

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

Claims

1. An optical imaging lens group having only four lenses, comprising in order from an object side to an image side along an optical axis:

a first lens having a positive optical power;

a second lens having a negative optical power;

a third lens having a negative focal power, an object side surface of the third lens being a convex surface;

a fourth lens having a positive optical power;

wherein, the on-axis distance TTL from the object side surface of the first lens to the imaging surface of the optical imaging lens group and the effective focal length f of the optical imaging lens group satisfy the following condition: TTL/f <1.0;

the effective focal length f of the optical imaging lens group, the effective focal length f1 of the first lens and the effective focal length f2 of the second lens satisfy the following conditions: 4.0 ≦ f/f1| + | f/f2| ≦ 5.0.

2. The optical imaging lens group of claim 1, wherein a center thickness CT3 of the third lens on the optical axis, and an air interval T34 of the third lens and the fourth lens on the optical axis satisfy: 0.5 ≦ T34/CT3 ≦ 2.5.

3. The optical imaging lens group of claim 1, wherein the effective focal length f2 of the second lens, the radius of curvature R3 of the object side surface of the second lens, and the radius of curvature R4 of the image side surface of the second lens satisfy: 0.5 ≦ (R3 + R4)/f 2| ≦ 1.5.

4. The optical imaging lens group of claim 1, wherein the effective focal length f1 of the first lens, the radius of curvature R4 of the image-side surface of the second lens, and the radius of curvature R5 of the object-side surface of the third lens satisfy: 0 ≦ (R4 + R5)/f 1 ≦ 2.0.

5. The optical imaging lens group according to claim 1, wherein a center thickness CT1 of said first lens on said optical axis, a center thickness CT2 of said second lens on said optical axis, a center thickness CT3 of said third lens on said optical axis, a center thickness CT4 of said fourth lens on said optical axis, and an air interval T12 of said first lens and said second lens on said optical axis satisfy: 0.5 ≦ (CT 1+ CT2+ T12)/(CT 3+ CT 4) ≦ 1.2.

6. The optical imaging lens group of claim 1, wherein a combined focal length f234 of the second lens, the third lens and the fourth lens, an effective focal length f2 of the second lens, satisfies: 0.5 ≦ f234/f2 ≦ 1.2.

7. The optical imaging lens group of claim 1, wherein an on-axis distance TTL from an object side surface of the first lens to an imaging surface of the optical imaging lens group and a distance SD from a stop of the optical imaging lens group to an image side surface of the fourth lens satisfy: TTL/SD is less than or equal to 2.0 and less than or equal to 4.2.

8. The optical imaging lens group of claim 1, wherein a distance BFL on the optical axis from an image side surface of the fourth lens to an image surface of the optical imaging lens group, a sum Σ CT of center thicknesses of all lenses on the optical axis satisfies: 2.0 ≦ BFL/Σ CT ≦ 3.5.

9. The optical imaging lens group according to claim 1, characterized in that between an effective focal length f1 of the first lens and an effective focal length f4 of the fourth lens, there are satisfied: f1/f4 is 0.6.

10. An optical imaging lens group having only four lenses, comprising in order from an object side to an image side along an optical axis:

a first lens having a positive optical power;

a second lens having a negative focal power, an object side surface of the second lens being a convex surface;

a fourth lens having a positive optical power;

the axial distance TTL from the object side surface of the first lens to the imaging surface of the optical imaging lens group and the effective focal length f of the optical imaging lens group meet the following conditions: TTL/f <1.0;

11. The optical imaging lens group of claim 10, wherein a center thickness CT3 of the third lens on the optical axis and an air interval T34 of the third lens and the fourth lens on the optical axis satisfy: 0.5 ≦ T34/CT3 ≦ 2.5.

12. The optical imaging lens group of claim 10, wherein the effective focal length f2 of the second lens, the radius of curvature R3 of the object side surface of the second lens, and the radius of curvature R4 of the image side surface of the second lens satisfy: 0.5 ≦ (R3 + R4)/f 2| ≦ 1.5.

13. The optical imaging lens group of claim 10, wherein the effective focal length f1 of the first lens, the radius of curvature R4 of the image-side surface of the second lens, and the radius of curvature R5 of the object-side surface of the third lens satisfy: 0 ≦ (R4 + R5)/f 1 ≦ 2.0.

14. The optical imaging lens group according to claim 10, wherein a center thickness CT1 of said first lens on said optical axis, a center thickness CT2 of said second lens on said optical axis, a center thickness CT3 of said third lens on said optical axis, a center thickness CT4 of said fourth lens on said optical axis, and an air interval T12 of said first lens and said second lens on said optical axis satisfy: 0.5 ≦ (CT 1+ CT2+ T12)/(CT 3+ CT 4) ≦ 1.2.

15. The optical imaging lens group according to claim 10, wherein a combined focal length f234 of the second lens, the third lens and the fourth lens, and an effective focal length f2 of the second lens satisfy: 0.5 ≦ f234/f2 ≦ 1.2.

16. The optical imaging lens group of claim 10, wherein an on-axis distance TTL from an object side surface of the first lens to an imaging surface of the optical imaging lens group and a distance SD from a stop of the optical imaging lens group to an image side surface of the fourth lens satisfy: 2.0 ≦ TTL/SD ≦ 4.2.

17. The optical imaging lens group of claim 10, wherein a distance BFL on the optical axis from an image side surface of the fourth lens to an image surface of the optical imaging lens group, a sum Σ CT of center thicknesses of all lenses on the optical axis satisfies: 2.0 ≦ BFL/Σ CT ≦ 3.5.

18. The optical imaging lens group of claim 10, wherein an effective focal length f1 of the first lens and an effective focal length f4 of the fourth lens satisfy: f1/f4 is 0 to 0.6.