CN112285893B

CN112285893B - Image pickup optical lens

Info

Publication number: CN112285893B
Application number: CN202011542344.7A
Authority: CN
Inventors: 寺岡弘之; 王燕妹
Original assignee: Changzhou Ruitai Photoelectric Co Ltd
Current assignee: Changzhou Ruitai Photoelectric Co Ltd
Priority date: 2020-12-24
Filing date: 2020-12-24
Publication date: 2021-03-09
Anticipated expiration: 2040-12-24
Also published as: CN112285893A

Abstract

The invention relates to the field of optical lenses, and discloses an image pickup optical lens, which comprises six lenses in sequence from an object side to an image side: a first lens element with positive refractive power, a second lens element with negative refractive power, a third lens element with positive refractive power, a fourth lens element with positive refractive power, a fifth lens element with positive refractive power, and a sixth lens element with negative refractive power; the focal length of the first lens is f1, the focal length of the second lens is f2, the on-axis distance from the image-side surface of the second lens to the object-side surface of the third lens is d4, the on-axis distance from the image-side surface of the third lens to the object-side surface of the fourth lens is d6, the central curvature radius of the object-side surface of the fourth lens is R7, the central curvature radius of the image-side surface of the fourth lens is R8, and the following relational expressions are satisfied: f1/f2 is more than or equal to-1.20 and less than or equal to-0.80, d4/d6 is more than or equal to 0.80 and less than or equal to 1.50, and (R7+ R8)/(R7-R8) is more than or equal to-20.00. The imaging optical lens provided by the invention has excellent optical characteristics, and has the characteristics of large aperture, long coking and ultra-thin thickness.

Description

Image pickup optical lens

Technical Field

The present invention relates to the field of optical lenses, and more particularly, to an imaging optical lens suitable for portable terminal devices such as smart phones and digital cameras, and imaging apparatuses such as monitors and PC lenses.

Background

In recent years, with the rise of various smart devices, the demand for miniaturized photographing optical lenses is increasing, and due to the reduction of the pixel size of the photosensitive device and the trend of the electronic products to have a good function and a light, thin and portable appearance, the miniaturized photographing optical lenses with good imaging quality are the mainstream in the market. In order to obtain better imaging quality, a multi-lens structure is often adopted. Moreover, with the development of technology and the increase of diversified demands of users, under the condition that the pixel area of the photosensitive device is continuously reduced and the requirement of the system on the imaging quality is continuously improved, the six-lens structure gradually appears in the design of the lens. There is a strong demand for a telephoto imaging lens having excellent optical characteristics, a small size, and sufficiently corrected aberrations.

Disclosure of Invention

In view of the above problems, an object of the present invention is to provide an imaging optical lens that has good optical performance and meets the design requirements of large aperture, ultra-thin thickness, and long coking.

To solve the above-mentioned problems, an embodiment of the present invention provides an imaging optical lens, which includes six lenses, in order from an object side to an image side: a first lens element with positive refractive power, a second lens element with negative refractive power, a third lens element with positive refractive power, a fourth lens element with positive refractive power, a fifth lens element with positive refractive power, and a sixth lens element with negative refractive power;

wherein a focal length of the first lens is f1, a focal length of the second lens is f2, an on-axis distance from an image-side surface of the second lens to an object-side surface of the third lens is d4, an on-axis distance from an image-side surface of the third lens to an object-side surface of the fourth lens is d6, a central curvature radius of an object-side surface of the fourth lens is R7, a central curvature radius of an image-side surface of the fourth lens is R8, and the following relations are satisfied:

-1.20≤f1/f2≤-0.80；

0.80≤d4/d6≤1.50；

-20.00≤(R7+R8)/(R7-R8)≤-10.00。

preferably, the object-side surface of the first lens element is convex at the paraxial region, and the image-side surface of the first lens element is convex at the paraxial region;

the focal length of the image pickup optical lens is f, the central curvature radius of the object side surface of the first lens is R1, the central curvature radius of the image side surface of the first lens is R2, the on-axis thickness of the first lens is d1, and the total optical length of the image pickup optical lens is TTL and satisfies the following relational expression:

0.30≤f1/f≤1.02；

-1.62≤(R1+R2)/(R1-R2)≤-0.38；

0.06≤d1/TTL≤0.20。

preferably, the imaging optical lens satisfies the following relation:

0.47≤f1/f≤0.82；

-1.01≤(R1+R2)/(R1-R2)≤-0.48；

0.09≤d1/TTL≤0.16。

preferably, the image-side surface of the second lens is concave at the paraxial region;

the focal length of the image pickup optical lens is f, the central curvature radius of the object side surface of the second lens is R3, the central curvature radius of the image side surface of the second lens is R4, the on-axis thickness of the second lens is d3, and the total optical length of the image pickup optical lens is TTL and satisfies the following relational expression:

-1.62≤f2/f≤-0.38；

0.29≤(R3+R4)/(R3-R4)≤2.16；

0.02≤d3/TTL≤0.09。

preferably, the imaging optical lens satisfies the following relation:

-1.01≤f2/f≤-0.47；

0.47≤(R3+R4)/(R3-R4)≤1.73；

0.04≤d3/TTL≤0.07。

preferably, the object-side surface of the third lens element is convex at the paraxial region, and the image-side surface of the third lens element is convex at the paraxial region;

the focal length of the image pickup optical lens is f, the focal length of the third lens is f3, the central curvature radius of the object side surface of the third lens is R5, the central curvature radius of the image side surface of the third lens is R6, the on-axis thickness of the third lens is d5, the total optical length of the image pickup optical lens is TTL, and the following relational expression is satisfied:

0.40≤f3/f≤2.23；

-0.87≤(R5+R6)/(R5-R6)≤-0.23；

0.06≤d5/TTL≤0.23。

preferably, the imaging optical lens satisfies the following relation:

0.64≤f3/f≤1.78；

-0.54≤(R5+R6)/(R5-R6)≤-0.29；

0.10≤d5/TTL≤0.18。

preferably, the object-side surface of the fourth lens element is convex at the paraxial region, and the image-side surface of the fourth lens element is concave at the paraxial region;

the focal length of the image pickup optical lens is f, the focal length of the fourth lens is f4, the on-axis thickness of the fourth lens is d7, the total optical length of the image pickup optical lens is TTL, and the following relational expression is satisfied:

53.11≤f4/f≤301.86；

0.03≤d7/TTL≤0.15。

preferably, the imaging optical lens satisfies the following relation:

84.98≤f4/f≤241.49；

0.05≤d7/TTL≤0.12。

preferably, the object-side surface of the fifth lens element is convex at the paraxial region, and the image-side surface of the fifth lens element is concave at the paraxial region;

the focal length of the image pickup optical lens is f, the focal length of the fifth lens is f5, the central curvature radius of the object side surface of the fifth lens is R9, the central curvature radius of the image side surface of the fifth lens is R10, the on-axis thickness of the fifth lens is d9, the total optical length of the image pickup optical lens is TTL, and the following relational expression is satisfied:

4.13≤f5/f≤78.56；

-399.94≤(R9+R10)/(R9-R10)≤43.82；

0.05≤d9/TTL≤0.17。

preferably, the imaging optical lens satisfies the following relation:

6.62≤f5/f≤62.84；

-249.96≤(R9+R10)/(R9-R10)≤35.05；

0.07≤d9/TTL≤0.14。

preferably, the object-side surface of the sixth lens element is concave at the paraxial region, and the image-side surface of the sixth lens element is concave at the paraxial region;

the focal length of the image pickup optical lens is f, the focal length of the sixth lens element is f6, the center curvature radius of the object-side surface of the sixth lens element is R11, the center curvature radius of the image-side surface of the sixth lens element is R12, the on-axis thickness of the sixth lens element is d11, the total optical length of the image pickup optical lens is TTL, and the following relational expression is satisfied:

-2.12≤f6/f≤-0.64；

0.07≤(R11+R12)/(R11-R12)≤0.80；

0.03≤d11/TTL≤0.10。

preferably, the imaging optical lens satisfies the following relation:

-1.33≤f6/f≤-0.80；

0.12≤(R11+R12)/(R11-R12)≤0.64；

0.05≤d11/TTL≤0.08。

preferably, the aperture value FNO of the imaging optical lens is less than or equal to 2.27.

Preferably, the aperture value FNO of the imaging optical lens is less than or equal to 2.22.

Preferably, the total optical length TTL of the image pickup optical lens is less than or equal to 8.18 millimeters.

Preferably, the total optical length TTL of the image pickup optical lens is less than or equal to 7.81 mm.

Preferably, the total optical length of the image pickup optical lens is TTL, the full field height of the image pickup optical lens is IH, and the following relationship is satisfied:

TTL/IH≤2.79。

preferably, the imaging optical lens satisfies the following relation:

TTL/IH≤2.71。

the invention has the beneficial effects that: the pick-up optical lens according to the present invention has excellent optical characteristics, and has characteristics of large aperture, long coking, and ultra-thin, and is particularly suitable for a mobile phone pick-up lens assembly and a WEB pick-up lens which are composed of pick-up elements such as a high-pixel CCD and a CMOS.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without inventive efforts, wherein:

fig. 1 is a schematic configuration diagram of an imaging optical lens according to a first embodiment of the present invention;

FIG. 2 is a schematic axial aberration diagram of the imaging optical lens of FIG. 1;

fig. 3 is a schematic diagram of chromatic aberration of magnification of the imaging optical lens shown in fig. 1;

FIG. 4 is a schematic view of curvature of field and distortion of the imaging optical lens of FIG. 1;

fig. 5 is a schematic configuration diagram of an imaging optical lens according to a second embodiment of the present invention;

FIG. 6 is a schematic axial aberration diagram of the imaging optical lens of FIG. 5;

fig. 7 is a schematic diagram of chromatic aberration of magnification of the imaging optical lens shown in fig. 5;

FIG. 8 is a schematic view of curvature of field and distortion of the imaging optical lens of FIG. 5;

fig. 9 is a schematic configuration diagram of an imaging optical lens according to a third embodiment of the present invention;

fig. 10 is a schematic view of axial aberrations of the image pickup optical lens shown in fig. 9;

fig. 11 is a schematic diagram of chromatic aberration of magnification of the imaging optical lens shown in fig. 9;

fig. 12 is a schematic view of curvature of field and distortion of the imaging optical lens shown in fig. 9.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, it will be appreciated by those of ordinary skill in the art that numerous technical details are set forth in order to provide a better understanding of the present invention in its various embodiments. However, the technical solution claimed in the present invention can be implemented without these technical details and various changes and modifications based on the following embodiments.

(first embodiment)

Referring to the drawings, the present invention provides an image pickup optical lens 10. Fig. 1 shows an imaging optical lens 10 according to a first embodiment of the present invention, and the imaging optical lens 10 includes six lenses in total. Specifically, the image capturing optical lens system 10, in order from an object side to an image side: the lens comprises a diaphragm S1, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5 and a sixth lens L6. An optical element such as an optical filter (filter) GF may be disposed between the sixth lens L6 and the image plane Si.

In this embodiment, the first lens L1 is made of plastic, the second lens L2 is made of plastic, the third lens L3 is made of plastic, the fourth lens L4 is made of plastic, the fifth lens L5 is made of plastic, and the sixth lens L6 is made of plastic. In other alternative embodiments, each lens may be made of other materials.

In this embodiment, the focal length of the first lens L1 is defined as f1, the focal length of the second lens L2 is defined as f2, the following relation-1.20 ≦ f1/f2 ≦ -0.80 is satisfied, and the ratio of the focal length f1 of the first lens L1 to the focal length f2 of the second lens L2 is defined, so that the system has better imaging quality and lower sensitivity through reasonable distribution of the focal lengths.

Defining an on-axis distance d4 from an image-side surface of the second lens L2 to an object-side surface of the third lens L3, and an on-axis distance d6 from an image-side surface of the third lens L3 to an object-side surface of the fourth lens L4, the following relations are satisfied: 0.80 < d4/d6 < 1.50, and the ratio of the on-axis distance d4 from the image-side surface of the second lens L2 to the object-side surface of the third lens L3 to the on-axis distance d6 from the image-side surface of the third lens L3 to the object-side surface of the fourth lens L4 is defined, which contributes to the reduction of the total optical length and the realization of the effect of making the optical device thinner within the conditional expression range.

The central curvature radius of the object side surface of the fourth lens L4 is defined as R7, the central curvature radius of the image side surface of the fourth lens L4 is defined as R8, and the following relations are satisfied: -20 ≦ (R7+ R8)/(R7-R8) ≦ -10, and the shape of the fourth lens L4 is controlled appropriately so that the fourth lens L4 can correct the system spherical aberration effectively.

In this embodiment, the object-side surface of the first lens element L1 is convex at the paraxial region thereof, and the image-side surface thereof is convex at the paraxial region thereof, and the first lens element L1 has positive refractive power. In other alternative embodiments, the object-side surface and the image-side surface of the first lens L1 may be arranged in other concave and convex distribution.

Defining the focal length of the image pickup optical lens as f, and satisfying the following relational expression: f1/f is more than or equal to 0.30 and less than or equal to 1.02; the ratio of the positive refractive power to the overall focal length of the first lens element L1 is specified. Within the specified range, the first lens element L1 has a positive refractive power, which is favorable for reducing system aberration and is favorable for the lens to be ultra-thin and long-coked. Preferably, 0.47. ltoreq. f 1/f. ltoreq.0.82 is satisfied.

The central curvature radius of the object side surface of the first lens L1 is defined as R1, the central curvature radius of the image side surface of the first lens L1 is defined as R2, and the following relational expressions are satisfied: 1.62 ≦ (R1+ R2)/(R1-R2) ≦ -0.38, and the shape of the first lens L1 is controlled appropriately so that the first lens L1 can correct the system spherical aberration effectively. Preferably, it satisfies-1.01 ≦ (R1+ R2)/(R1-R2) ≦ -0.48.

The on-axis thickness of the first lens L1 is d1, the total optical length of the imaging optical lens system 10 is TTL, and the following relations are satisfied: d1/TTL is more than or equal to 0.06 and less than or equal to 0.20, and ultra-thinning is facilitated in the conditional expression range. Preferably, 0.09. ltoreq. d 1/TTL. ltoreq.0.16 is satisfied.

In this embodiment, the object-side surface of the second lens element L2 is concave at the paraxial region, the image-side surface thereof is concave at the paraxial region, and the second lens element L2 has negative refractive power. In other alternative embodiments, the object-side surface and the image-side surface of the second lens L2 may be arranged in other concave and convex distribution.

Defining the focal length f of the image pickup optical lens 10 and the focal length f2 of the second lens L2, the following relations are satisfied: 1.62 ≦ f2/f ≦ -0.38, and it is advantageous to correct aberrations of the optical system by controlling the negative power of the second lens L2 within a reasonable range. Preferably, it satisfies-1.01. ltoreq. f 2/f. ltoreq-0.47.

The central curvature radius of the object side surface of the second lens L2 is R3, the central curvature radius of the image side surface of the second lens L2 is R4, and the following relational expression is satisfied: the (R3+ R4)/(R3-R4) is not more than 0.29 and not more than 2.16, the shape of the second lens L2 can be effectively controlled, the molding of the second lens L2 is facilitated, the deflection degree of light rays passing through the lens can be alleviated within the range specified by the conditional expression, and the aberration can be effectively reduced. Preferably, 0.47 ≦ (R3+ R4)/(R3-R4) ≦ 1.73.

The on-axis thickness of the second lens L2 is d3, the total optical length of the imaging optical lens system 10 is TTL, and the following relationship is satisfied: d3/TTL is more than or equal to 0.02 and less than or equal to 0.09, and ultra-thinning is favorably realized within the range of conditional expressions. Preferably, 0.04. ltoreq. d 3/TTL. ltoreq.0.07 is satisfied.

In this embodiment, the object-side surface of the third lens element L3 is convex at the paraxial region thereof, and the image-side surface thereof is convex at the paraxial region thereof, and the third lens element L3 has positive refractive power. In other alternative embodiments, the object-side surface and the image-side surface of the third lens L3 may be arranged in other concave and convex distribution.

Defining the focal length of the image pickup optical lens 10 as f, and the focal length of the third lens L3 as f3, the following relations are satisfied: f3/f is more than or equal to 0.40 and less than or equal to 2.23, and the system has better imaging quality and lower sensitivity through reasonable distribution of the focal power. Preferably, 0.64. ltoreq. f 3/f. ltoreq.1.78 is satisfied.

The central curvature radius of the object side surface of the third lens L3 is R5, the central curvature radius of the image side surface of the third lens L3 is R6, and the following relational expressions are satisfied: -0.87 ≦ (R5+ R6)/(R5-R6) ≦ -0.23, defines the shape of the third lens L3, facilitates the molding of the third lens L3, and can alleviate the deflection degree of the light passing through the lens within the range defined by the conditional expression, and effectively reduce the aberration. Preferably, it satisfies-0.54 ≦ (R5+ R6)/(R5-R6). ltoreq.0.29.

The on-axis thickness of the third lens L3 is d5, the total optical length of the imaging optical lens system 10 is TTL, and the following relationship is satisfied: d5/TTL is more than or equal to 0.06 and less than or equal to 0.23, and ultra-thinning is facilitated in the conditional expression range. Preferably, 0.10. ltoreq. d 5/TTL. ltoreq.0.18 is satisfied.

In this embodiment, the object-side surface of the fourth lens element L4 is convex at the paraxial region thereof, the image-side surface thereof is concave at the paraxial region thereof, and the fourth lens element L4 has positive refractive power. In other alternative embodiments, the object-side surface and the image-side surface of the fourth lens L4 may be arranged in other concave and convex distribution situations.

Defining the focal length f of the image pickup optical lens 10 and the focal length f4 of the fourth lens L4, the following relations are satisfied: 53.11 ≦ f4/f ≦ 301.86, which makes the system have better imaging quality and lower sensitivity by reasonable distribution of the optical power. Preferably, 84.98. ltoreq. f 4/f. ltoreq. 241.49 is satisfied.

The on-axis thickness of the fourth lens L4 is d7, the total optical length of the imaging optical lens system 10 is TTL, and the following relationship is satisfied: d7/TTL is more than or equal to 0.03 and less than or equal to 0.15, and ultra-thinning is favorably realized within the range of conditional expressions. Preferably, 0.05. ltoreq. d 7/TTL. ltoreq.0.12 is satisfied.

In this embodiment, the object-side surface of the fifth lens element L5 is convex at the paraxial region, the image-side surface thereof is concave at the paraxial region, and the fifth lens element L5 has positive refractive power. In other alternative embodiments, the object-side surface and the image-side surface of the fifth lens L5 may be arranged in other concave and convex distribution.

Defining the focal length f of the image pickup optical lens 10 and the focal length f5 of the fifth lens L5, the following relations are satisfied: 4.13 is less than or equal to f5/f is less than or equal to 78.56, and the definition of the fifth lens L5 can effectively make the light ray angle of the shooting optical lens 10 smooth and reduce tolerance sensitivity. Preferably, 6.62. ltoreq. f 5/f. ltoreq. 62.84 is satisfied.

The central curvature radius of the object side surface of the fifth lens L5 is R9, the central curvature radius of the image side surface of the fifth lens L5 is R10, and the following relations are satisfied: the value of (R9+ R10)/(R9-R10) is not more than 399.94 and not more than 43.82, the shape of the fifth lens L5 is defined, and when the shape is within the range, the problems such as aberration of an off-axis picture angle and the like are favorably corrected along with the development of ultra-thin long coking. Preferably, it satisfies-249.96 ≦ (R9+ R10)/(R9-R10). ltoreq.35.05.

The on-axis thickness of the fifth lens L5 is d9, the total optical length of the imaging optical lens system 10 is TTL, and the following relationship is satisfied: d9/TTL is more than or equal to 0.05 and less than or equal to 0.17, and ultra-thinning is facilitated in the condition formula range. Preferably, 0.07. ltoreq. d 9/TTL. ltoreq.0.14 is satisfied.

In this embodiment, the object-side surface of the sixth lens element L6 is concave at the paraxial region, the image-side surface thereof is concave at the paraxial region, and the sixth lens element L6 has negative refractive power. In other alternative embodiments, the object-side surface and the image-side surface of the sixth lens L6 may be arranged in other concave and convex distribution.

Defining the focal length f of the image pickup optical lens 10 and the focal length f6 of the sixth lens L6, the following relations are satisfied: 2.12 ≦ f6/f ≦ -0.64, allowing better imaging quality and lower sensitivity of the system through reasonable distribution of optical power. Preferably, it satisfies-1.33. ltoreq. f 6/f. ltoreq-0.80.

The center curvature radius of the object side surface of the sixth lens L6 is R11, the center curvature radius of the image side surface of the sixth lens L6 is R12, and the following relations are satisfied: the ratio of (R11+ R12)/(R11-R12) is 0.07-0.80, the shape of the sixth lens L6 is defined, and the problems such as aberration of the off-axis picture angle and the like are favorably corrected as the ultra-thin long-coking progresses in the condition range. Preferably, 0.12. ltoreq. (R11+ R12)/(R11-R12). ltoreq.0.64 is satisfied.

The on-axis thickness of the sixth lens element L6 is d11, the total optical length of the imaging optical lens system 10 is TTL, and the following relationships are satisfied: d11/TTL is more than or equal to 0.03 and less than or equal to 0.10, and ultra-thinning is favorably realized within the range of conditional expressions. Preferably, 0.05. ltoreq. d 11/TTL. ltoreq.0.08 is satisfied.

In this embodiment, the aperture value FNO of the image pickup optical lens 10 is defined as FNO, and the aperture value FNO of the image pickup optical lens 10 is less than or equal to 2.27, so that a large aperture is realized, and the image pickup optical lens has good imaging performance. Preferably, the aperture value FNO of the imaging optical lens 10 is less than or equal to 2.22.

In this embodiment, the total optical length of the image pickup optical lens 10 is defined as TTL, and the total optical length TTL of the image pickup optical lens 10 is less than or equal to 8.18mm, thereby facilitating ultra-thinning. Preferably, the total optical length TTL of the image pickup optical lens 10 is less than or equal to 7.81 mm.

In this embodiment, the total optical length of the image pickup optical lens 10 is defined as TTL, the full field height of the image pickup optical lens 10 is defined as IH, and the following relational expression is satisfied: TTL/IH is less than or equal to 2.79, thereby being beneficial to realizing ultra-thinning. Preferably, TTL/IH ≦ 2.71 is satisfied.

The shooting optical lens 10 has good optical performance and can meet the design requirements of large aperture, long coking and ultra-thinning; in accordance with the characteristics of the imaging optical lens 10, the imaging optical lens 10 is particularly suitable for a mobile phone imaging lens module and a WEB imaging lens which are configured by an imaging element such as a high-pixel CCD or a CMOS.

The image pickup optical lens 10 of the present invention will be explained below by way of example. The symbols described in the respective examples are as follows. The unit of focal length, on-axis distance, center curvature radius, on-axis thickness, position of the reverse curvature point and the position of the stagnation point is mm.

TTL: the total optical length (on-axis distance from the object side surface of the first lens L1 to the image plane Si) is in mm;

aperture value FNO: is the ratio of the effective focal length and the entrance pupil diameter of the imaging optical lens.

Preferably, the object side surface and/or the image side surface of the lens may be further provided with an inflection point and/or a stagnation point to meet the requirement of high-quality imaging.

Tables 1 and 2 show design data of the imaging optical lens 10 according to the first embodiment of the present invention.

[ TABLE 1 ]

Wherein each symbol has the following meaning.

S1: an aperture;

r: a radius of curvature at the center of the optical surface;

r1: the center radius of curvature of the object side of the first lens L1;

r2: the central radius of curvature of the image-side surface of the first lens L1;

r3: the center radius of curvature of the object side of the second lens L2;

r4: the central radius of curvature of the image-side surface of the second lens L2;

r5: the center radius of curvature of the object side of the third lens L3;

r6: the central radius of curvature of the image-side surface of the third lens L3;

r7: the center radius of curvature of the object side of the fourth lens L4;

r8: the central radius of curvature of the image-side surface of the fourth lens L4;

r9: the center radius of curvature of the object side of the fifth lens L5;

r10: the center radius of curvature of the image-side surface of the fifth lens L5;

r11: the center radius of curvature of the object side of the sixth lens L6;

r12: the center radius of curvature of the image-side surface of the sixth lens L6;

r13: the central radius of curvature of the object side of the optical filter GF;

r14: the center radius of curvature of the image side of the optical filter GF;

d: on-axis thickness of the lenses, on-axis distance between the lenses;

d 0: the on-axis distance of the stop S1 to the object-side surface of the first lens L1;

d 1: the on-axis thickness of the first lens L1;

d 2: the on-axis distance from the image-side surface of the first lens L1 to the object-side surface of the second lens L2;

d 3: the on-axis thickness of the second lens L2;

d 4: the on-axis distance from the image-side surface of the second lens L2 to the object-side surface of the third lens L3;

d 5: the on-axis thickness of the third lens L3;

d 6: the on-axis distance from the image-side surface of the third lens L3 to the object-side surface of the fourth lens L4;

d 7: the on-axis thickness of the fourth lens L4;

d 8: an on-axis distance from an image-side surface of the fourth lens L4 to an object-side surface of the fifth lens L5;

d 9: the on-axis thickness of the fifth lens L5;

d 10: an on-axis distance from an image-side surface of the fifth lens L5 to an object-side surface of the sixth lens L6;

d 11: the on-axis thickness of the sixth lens L6;

d 12: the on-axis distance from the image-side surface of the sixth lens L6 to the object-side surface of the optical filter GF;

d 13: on-axis thickness of the optical filter GF;

d 14: the axial distance from the image side surface of the optical filter GF to the image surface Si;

nd: refractive index of d-line (d-line is green light with wavelength of 550 nm);

nd 1: the refractive index of the d-line of the first lens L1;

nd 2: the refractive index of the d-line of the second lens L2;

nd 3: the refractive index of the d-line of the third lens L3;

nd 4: the refractive index of the d-line of the fourth lens L4;

nd 5: the refractive index of the d-line of the fifth lens L5;

nd 6: the refractive index of the d-line of the sixth lens L6;

ndg: the refractive index of the d-line of the optical filter GF;

vd: an Abbe number;

v 1: abbe number of the first lens L1;

v 2: abbe number of the second lens L2;

v 3: abbe number of the third lens L3;

v 4: abbe number of the fourth lens L4;

v 5: abbe number of the fifth lens L5;

v 6: abbe number of the sixth lens L6;

vg: abbe number of the optical filter GF.

Table 2 shows aspherical surface data of each lens in the imaging optical lens 10 according to the first embodiment of the present invention.

[ TABLE 2 ]

For convenience, an aspherical surface shown in the following formula (1) is used as an aspherical surface of each lens surface. However, the present invention is not limited to the aspherical polynomial form expressed by this formula (1).

z=(cr²)/{1+[1-(k+1)(c²r²)]^1/2}+A4r⁴+A6r⁶+A8r⁸+A10r¹⁰+A12r¹²+

A14r¹⁴+A16r¹⁶+A18r¹⁸+A20r²⁰（1）

Where k is a conic coefficient, a4, a6, A8, a10, a12, a14, a16, a18, a20 are aspheric coefficients, c is a curvature at the center of the optical surface, r is a perpendicular distance from a point on an aspheric curve to the optical axis, and z is an aspheric depth (a perpendicular distance between a point on an aspheric surface at a distance of r from the optical axis and a tangent plane tangent to a vertex on the aspheric optical axis).

Tables 3 and 4 show the inflection point and stagnation point design data of each lens in the imaging optical lens 10 according to the first embodiment of the present invention. P1R1 and P1R2 represent the object-side surface and the image-side surface of the first lens L1, P2R1 and P2R2 represent the object-side surface and the image-side surface of the second lens L2, P3R1 and P3R2 represent the object-side surface and the image-side surface of the third lens L3, P4R1 and P4R2 represent the object-side surface and the image-side surface of the fourth lens L4, P5R1 and P5R2 represent the object-side surface and the image-side surface of the fifth lens L5, and P6R1 and P6R2 represent the object-side surface and the image-side surface of the sixth lens L6, respectively. The "inflection point position" field correspondence data is a vertical distance from an inflection point set on each lens surface to the optical axis of the image pickup optical lens 10. The "stagnation point position" field corresponding data is the vertical distance from the stagnation point set on each lens surface to the optical axis of the imaging optical lens 10.

[ TABLE 3 ]

[ TABLE 4 ]

Fig. 2 and 3 are schematic diagrams showing axial aberrations and chromatic aberrations of magnification after light having wavelengths of 486nm, 588nm and 656nm passes through the imaging optical lens 10 according to the first embodiment. Fig. 4 is a schematic view showing curvature of field and distortion of light having a wavelength of 588nm after passing through the imaging optical lens 10 according to the first embodiment, where S is curvature of field in the sagittal direction and T is curvature of field in the tangential direction in fig. 4.

Table 13 shown later shows values corresponding to the parameters specified in the conditional expressions for the respective numerical values in the first, second, and third examples.

As shown in table 13, the first embodiment satisfies each conditional expression.

In the present embodiment, the imaging optical lens 10 has an entrance pupil diameter ENPD of 2.823mm, a full field image height IH of 2.800mm, and a diagonal field angle FOV of 48.53 °, and the imaging optical lens 10 satisfies the design requirements of large aperture, long-focus, and slimness, and has excellent optical characteristics with on-axis and off-axis chromatic aberration sufficiently corrected.

(second embodiment)

The second embodiment is basically the same as the first embodiment, the same reference numerals as in the first embodiment, and only different points will be described below.

Fig. 5 shows an imaging optical lens 20 according to a second embodiment of the present invention.

Tables 5 and 6 show design data of the imaging optical lens 20 according to the second embodiment of the present invention.

[ TABLE 5 ]

Table 6 shows aspherical surface data of each lens in the imaging optical lens 20 according to the second embodiment of the present invention.

[ TABLE 6 ]

Tables 7 and 8 show the inflection point and stagnation point design data of each lens in the imaging optical lens 20 according to the second embodiment of the present invention.

[ TABLE 7 ]

[ TABLE 8 ]

Fig. 6 and 7 are schematic diagrams showing axial aberrations and chromatic aberrations of magnification of light having wavelengths of 486nm, 588nm, and 656nm passing through the imaging optical lens 20 according to the second embodiment. Fig. 8 is a schematic view showing curvature of field and distortion of light having a wavelength of 588nm after passing through the imaging optical lens 20 according to the second embodiment. The field curvature S in fig. 8 is a field curvature in the sagittal direction, and T is a field curvature in the tangential direction.

As shown in table 13, the second embodiment satisfies each conditional expression.

In the present embodiment, the imaging optical lens 20 has an entrance pupil diameter ENPD of 2.829mm, a full field image height IH of 2.800mm, and a diagonal field angle FOV of 48.44 °, and the imaging optical lens 20 satisfies the design requirements of large aperture, long-focus, and slimness, and has excellent optical characteristics with on-axis and off-axis chromatic aberration sufficiently corrected.

(third embodiment)

The third embodiment is basically the same as the first embodiment, the same reference numerals as in the first embodiment, and only different points will be described below.

In this embodiment, the object-side surface of the second lens element L2 is convex at the paraxial region.

Fig. 9 shows an imaging optical lens 30 according to a third embodiment of the present invention.

Tables 9 and 10 show design data of the imaging optical lens 30 according to the third embodiment of the present invention.

[ TABLE 9 ]

Table 10 shows aspherical surface data of each lens in the imaging optical lens 30 according to the third embodiment of the present invention.

[ TABLE 10 ]

Tables 11 and 12 show the inflection points and the stagnation point design data of each lens in the imaging optical lens 30 according to the third embodiment of the present invention.

[ TABLE 11 ]

[ TABLE 12 ]

Fig. 10 and 11 are schematic diagrams showing axial aberrations and chromatic aberrations of magnification after light having wavelengths of 486nm, 588nm, and 656nm passes through the imaging optical lens 30 according to the third embodiment. Fig. 12 is a schematic view showing curvature of field and distortion of light having a wavelength of 588nm after passing through the imaging optical lens 30 according to the third embodiment. The field curvature S in fig. 12 is a field curvature in the sagittal direction, and T is a field curvature in the tangential direction.

Table 13 below shows the numerical values corresponding to the respective conditional expressions in the present embodiment, in accordance with the conditional expressions described above. Obviously, the imaging optical lens 30 of the present embodiment satisfies the above conditional expressions.

In the present embodiment, the imaging optical lens 30 has an entrance pupil diameter ENPD of 2.763mm, a full field height IH of 2.800mm, and a diagonal field angle FOV of 49.47 °, and the imaging optical lens 30 satisfies the design requirements of large aperture, long-focus, and slimness, and has excellent optical characteristics with on-axis and off-axis chromatic aberration sufficiently corrected.

[ TABLE 13 ]

It will be understood by those of ordinary skill in the art that the foregoing embodiments are specific embodiments for practicing the invention, and that various changes in form and details may be made therein without departing from the spirit and scope of the invention in practice.

Claims

1. An imaging optical lens, comprising six lens elements in order from an object side to an image side: a first lens element with positive refractive power, a second lens element with negative refractive power, a third lens element with positive refractive power, a fourth lens element with positive refractive power, a fifth lens element with positive refractive power, and a sixth lens element with negative refractive power;

the object side surface of the first lens is convex at the paraxial part, and the image side surface of the first lens is convex at the paraxial part; the image side surface of the second lens is concave at the paraxial position; the object side surface of the third lens is convex at the paraxial position, and the image side surface of the third lens is convex at the paraxial position; the object side surface of the fourth lens is convex at the paraxial position, and the image side surface of the fourth lens is concave at the paraxial position; the object side surface of the fifth lens is convex at the paraxial position, and the image side surface of the fifth lens is concave at the paraxial position; the object side surface of the sixth lens is concave at the paraxial region, and the image side surface of the sixth lens is concave at the paraxial region;

wherein a focal length of the first lens is f1, a focal length of the second lens is f2, an on-axis distance from an image-side surface of the second lens to an object-side surface of the third lens is d4, an on-axis distance from an image-side surface of the third lens to an object-side surface of the fourth lens is d6, a central curvature radius of an object-side surface of the fourth lens is R7, a central curvature radius of an image-side surface of the fourth lens is R8, and the following relations are satisfied: f1/f2 is not less than 1.20 and not more than 0.80; d4/d6 is more than or equal to 0.80 and less than or equal to 1.50; the ratio of (R7+ R8)/(R7-R8) is more than or equal to-20.00 and less than or equal to-10.00.

2. The image-capturing optical lens of claim 1, wherein the focal length of the image-capturing optical lens is f, the central radius of curvature of the object-side surface of the first lens is R1, the central radius of curvature of the image-side surface of the first lens is R2, the on-axis thickness of the first lens is d1, the total optical length of the image-capturing optical lens is TTL, and the following relationship is satisfied: f1/f is more than or equal to 0.30 and less than or equal to 1.02; -1.62 ≦ (R1+ R2)/(R1-R2) ≦ -0.38; d1/TTL is more than or equal to 0.06 and less than or equal to 0.20.

3. The imaging optical lens according to claim 2, wherein the imaging optical lens satisfies the following relationship: f1/f is more than or equal to 0.47 and less than or equal to 0.82; -1.01 ≤ (R1+ R2)/(R1-R2) is ≤ 0.48; d1/TTL is more than or equal to 0.09 and less than or equal to 0.16.

4. The image-capturing optical lens of claim 1, wherein the focal length of the image-capturing optical lens is f, the center radius of curvature of the object-side surface of the second lens is R3, the center radius of curvature of the image-side surface of the second lens is R4, the on-axis thickness of the second lens is d3, the total optical length of the image-capturing optical lens is TTL, and the following relationship is satisfied: f2/f is not less than 1.62 and not more than-0.38; (R3+ R4)/(R3-R4) is not more than 0.29 and not more than 2.16; d3/TTL is more than or equal to 0.02 and less than or equal to 0.09.

5. The imaging optical lens according to claim 4, wherein the imaging optical lens satisfies the following relation: f2/f is not less than 1.01 and not more than-0.47; (R3+ R4)/(R3-R4) is not more than 0.47 and not more than 1.73; d3/TTL is more than or equal to 0.04 and less than or equal to 0.07.

6. The imaging optical lens of claim 1, wherein the focal length of the imaging optical lens is f, the focal length of the third lens is f3, the central radius of curvature of the object-side surface of the third lens is R5, the central radius of curvature of the image-side surface of the third lens is R6, the on-axis thickness of the third lens is d5, the total optical length of the imaging optical lens is TTL, and the following relationships are satisfied: f3/f is more than or equal to 0.40 and less than or equal to 2.23; -0.87 ≤ (R5+ R6)/(R5-R6) ≤ 0.23; d5/TTL is more than or equal to 0.06 and less than or equal to 0.23.

7. The imaging optical lens according to claim 6, wherein the imaging optical lens satisfies the following relation: f3/f is more than or equal to 0.64 and less than or equal to 1.78; -0.54 ≤ (R5+ R6)/(R5-R6) ≤ 0.29; d5/TTL is more than or equal to 0.10 and less than or equal to 0.18.

8. The image-capturing optical lens of claim 1, wherein the focal length of the image-capturing optical lens is f, the focal length of the fourth lens is f4, the on-axis thickness of the fourth lens is d7, the total optical length of the image-capturing optical lens is TTL, and the following relationship is satisfied: 53.11 is less than or equal to f4/f is less than or equal to 301.86; d7/TTL is more than or equal to 0.03 and less than or equal to 0.15.

9. The image-pickup optical lens according to claim 8, wherein the image-pickup optical lens satisfies the following relation: f4/f is not less than 84.98 and not more than 241.49; d7/TTL is more than or equal to 0.05 and less than or equal to 0.12.

10. The image-capturing optical lens of claim 1, wherein the focal length of the image-capturing optical lens is f, the focal length of the fifth lens is f5, the central radius of curvature of the object-side surface of the fifth lens is R9, the central radius of curvature of the image-side surface of the fifth lens is R10, the on-axis thickness of the fifth lens is d9, the total optical length of the image-capturing optical lens is TTL, and the following relationships are satisfied: f5/f is not less than 4.13 and not more than 78.56; -399.94 (R9+ R10)/(R9-R10) is less than or equal to 43.82; d9/TTL is more than or equal to 0.05 and less than or equal to 0.17.

11. The image-pickup optical lens according to claim 10, wherein the image-pickup optical lens satisfies the following relation: f5/f is not less than 6.62 and not more than 62.84; -249.96 (R9+ R10)/(R9-R10) is less than or equal to 35.05; d9/TTL is more than or equal to 0.07 and less than or equal to 0.14.

12. The image-capturing optical lens unit according to claim 1, wherein the image-capturing optical lens unit has a focal length f, the sixth lens unit has a focal length f6, the object-side surface of the sixth lens unit has a central radius of curvature R11, the image-side surface of the sixth lens unit has a central radius of curvature R12, the sixth lens unit has an on-axis thickness d11, the image-capturing optical lens unit has a total optical length TTL, and satisfies the following relationships: f6/f is not less than-2.12 and not more than-0.64; (R11+ R12)/(R11-R12) is not more than 0.07 but not more than 0.80; d11/TTL is more than or equal to 0.03 and less than or equal to 0.10.

13. The image-pickup optical lens according to claim 12, wherein the image-pickup optical lens satisfies the following relation: f6/f is not less than 1.33 and not more than-0.80; (R11+ R12)/(R11-R12) is not more than 0.12 and not more than 0.64; d11/TTL is more than or equal to 0.05 and less than or equal to 0.08.

14. The imaging optical lens according to claim 1, wherein an aperture value FNO of the imaging optical lens is less than or equal to 2.27.

15. The imaging optical lens according to claim 14, wherein an aperture value FNO of the imaging optical lens is less than or equal to 2.22.

16. A camera optical lens according to claim 1, characterized in that the total optical length TTL of the camera optical lens is less than or equal to 8.18 mm.

17. A camera optical lens according to claim 16, characterized in that the total optical length TTL of the camera optical lens is less than or equal to 7.81 mm.

18. A camera optical lens according to claim 1, wherein the total optical length of the camera optical lens is TTL, the full field height of the camera optical lens is IH, and the following relationship is satisfied:

TTL/IH≤2.79。

19. the image-pickup optical lens according to claim 18, wherein the image-pickup optical lens satisfies the following relationship:

TTL/IH≤2.71。