CN110908081A

CN110908081A - Image pickup optical lens

Info

Publication number: CN110908081A
Application number: CN201911338369.2A
Authority: CN
Inventors: 孙雯
Original assignee: Ruisheng Communication Technology Changzhou Co Ltd
Current assignee: AAC Communication Technologies Changzhou Co Ltd; Ruisheng Communication Technology Changzhou Co Ltd
Priority date: 2019-12-23
Filing date: 2019-12-23
Publication date: 2020-03-24
Anticipated expiration: 2039-12-23
Also published as: CN110908081B

Abstract

The invention relates to the field of optical lenses, and discloses an image pickup optical lens, which sequentially comprises from an object side to an image side: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens; and satisfies the following relationships: f1/f is more than or equal to 0.6 and less than or equal to 1.8; f2 is less than or equal to 0 mm; 2 is less than or equal to (R5+ R6)/(R5-R6) is less than or equal to 7; d3/d4 is more than or equal to 1.1 and less than or equal to 3.8. The camera optical lens has good optical performance such as large aperture, ultrathin property and the like.

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 smart phones, the demand of miniaturized camera lenses is increasing, and the photosensitive devices of general camera lenses are not limited to two types, namely, a Charge Coupled Device (CCD) or a Complementary Metal-oxide semiconductor (CMOS) Device, and due to the refinement of semiconductor manufacturing technology, the pixel size of the photosensitive devices is reduced, and in addition, the current electronic products are developed with a good function, a light weight, a small size, and a light weight, and thus, the miniaturized camera lenses with good imaging quality are the mainstream in the current market. In order to obtain better imaging quality, the lens mounted on the mobile phone camera conventionally adopts a three-piece or four-piece lens structure. 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 eight-piece lens structure gradually appears in the design of the lens. It is urgently required to provide a large-aperture, ultra-thin optical imaging lens having good optical performance.

Disclosure of Invention

In view of the above problems, an object of the present invention is to provide an imaging optical lens that can satisfy the requirements of a large aperture and an ultra-thin profile while achieving high imaging performance.

To solve the above-mentioned problems, an embodiment of the present invention provides an imaging optical lens, in order from an object side to an image side, comprising: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens;

the focal length of the imaging optical lens is f, the focal length of the first lens is f1, the focal length of the second lens is f2, the curvature radius of the object-side surface of the third lens is R5, the curvature radius of the image-side surface of the third lens is R6, the on-axis thickness of the second lens is d3, and the on-axis distance from the image-side surface of the second lens to the object-side surface of the third lens is d4, so that the following relational expression is satisfied:

0.6≤f1/f≤1.8；

f2≤0mm；

2≤(R5+R6)/(R5-R6)≤7；

1.1≤d3/d4≤3.8。

preferably, the on-axis thickness of the sixth lens is d11, the on-axis distance from the image-side surface of the sixth lens to the object-side surface of the seventh lens is d12, and the following relation is satisfied:

0.9≤d11/d12≤11。

preferably, a curvature radius of an object-side surface of the first lens is R1, a curvature radius of an image-side surface of the first lens is R2, and an on-axis thickness of the first lens is d1, an optical total length of the imaging optical lens is TTL, and the following relational expression is satisfied:

-5.68≤(R1+R2)/(R1-R2)≤-0.28；

0.04≤d1/TTL≤0.18。

preferably, the curvature radius of the object-side surface of the second lens element is R3, the curvature radius of the image-side surface of the second lens element is R4, and the total optical length of the imaging optical lens system is TTL and satisfies the following relation:

-14.42≤f2/f≤-1.24；

-0.93≤(R3+R4)/(R3-R4)≤13.90；

0.02≤d3/TTL≤0.08。

preferably, the focal length of the third lens is f3, the on-axis thickness of the third lens is d5, the total optical length of the imaging optical lens is TTL, and the following relation is satisfied:

-6.60≤f3/f≤-1.31；

0.02≤d5/TTL≤0.05。

preferably, the focal length of the fourth lens element is f4, the radius of curvature of the object-side surface of the fourth lens element is R7, the radius of curvature of the image-side surface of the fourth lens element is R8, and the on-axis thickness of the fourth lens element is d7, the total optical length of the image pickup optical lens is TTL, and the following relationships are satisfied:

-171.86≤f4/f≤23.11；

-5.29≤(R7+R8)/(R7-R8)≤14.49；

0.03≤d7/TTL≤0.15。

preferably, the focal length of the fifth lens element is f5, the curvature radius of the object-side surface of the fifth lens element is R9, the curvature radius of the image-side surface of the fifth lens element is R10, and the on-axis thickness of the fifth lens element is d9, the total optical length of the image pickup optical lens is TTL, and the following relationships are satisfied:

-5.35≤f5/f≤5.57；

-2.76≤(R9+R10)/(R9-R10)≤4.68；

0.02≤d9/TTL≤0.10。

preferably, the focal length of the sixth lens element is f6, the radius of curvature of the object-side surface of the sixth lens element is R11, the radius of curvature of the image-side surface of the sixth lens element is R12, and the total optical length of the imaging optical lens system is TTL and satisfies the following relation:

-20.52≤f6/f≤-1.64；

-15.18≤(R11+R12)/(R11-R12)≤-1.56；

0.02≤d11/TTL≤0.07。

preferably, the focal length of the seventh lens element is f7, the on-axis curvature radius of the object-side surface of the seventh lens element is R13, the on-axis curvature radius of the image-side surface of the seventh lens element is R14, the on-axis thickness of the seventh lens element is d13, the total optical length of the imaging optical lens system is TTL, and the following relationships are satisfied:

0.45≤f7/f≤1.47；

-4.18≤(R13+R14)/(R13-R14)≤-0.67；

0.04≤d13/TTL≤0.16。

preferably, the focal length of the eighth lens element is f8, the curvature radius of the object-side surface of the eighth lens element is R15, the curvature radius of the image-side surface of the eighth lens element is R16, and the on-axis thickness of the eighth lens element is d15, the total optical length of the imaging optical lens system is TTL, and the following relationships are satisfied:

-1.62≤f8/f≤-0.48；

0.01≤(R15+R16)/(R15-R16)≤0.45；

0.03≤d15/TTL≤0.09。

the invention has the beneficial effects that: the pick-up optical lens according to the present invention has excellent optical characteristics, satisfies the requirements of large aperture 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

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 eight lenses. Specifically, the imaging optical lens 10, in order from an object side to an image side, includes: the stop S1, the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, the fifth lens L5, the sixth lens L6, the seventh lens L7, and the eighth lens L8. An optical element such as an optical filter (filter) GF may be disposed between the eighth lens L8 and the image plane Si.

Defining the focal length f of the entire image pickup optical lens 10 and the focal length f1 of the first lens L1, the following relations are satisfied: f1/f is more than or equal to 0.6 and less than or equal to 1.8, the first lens L1 has positive refractive power within the conditional expression, the ratio of the focal length of the first lens to the total focal length is specified, and the system total length is favorably reduced within the conditional expression. Preferably, 0.62. ltoreq. f 1/f. ltoreq.1.78 is satisfied.

Defining the focal length of the second lens L2 as f2, the following relation is satisfied: f2 is less than or equal to 0mm, the focal length of the second lens is regulated, the system aberration correction is facilitated, and the imaging quality is improved. Preferably, f2 is ≦ 6.282 mm.

The radius of curvature of the object side surface of the third lens L3 is R5, the radius of curvature of the image side surface of the third lens L3 is R6, 2 ≦ (R5+ R6)/(R5-R6) ≦ 7, and the shape of the third lens is defined to help reduce the degree of beam deflection and reduce aberration. Preferably, 2.22. ltoreq. (R5+ R6)/(R5-R6). ltoreq.6.97 is satisfied.

Defining the on-axis thickness of the second lens L2 as d3, and the on-axis distance from the image-side surface of the second lens L2 to the object-side surface of the third lens L3 as d4, the following relationships are satisfied: 1.1 is less than or equal to d3/d4 is less than or equal to 3.8, the ratio of the thickness of the second lens to the air spacing distance of the second third lens is specified, and the imaging performance is improved within the condition range. Satisfies d3/d4 of 1.11-3.78.

Defining the on-axis thickness of the sixth lens L6 as d11, and the on-axis distance from the image-side surface of the sixth lens L6 to the object-side surface of the seventh lens L7 as d12, the following relationships are satisfied: 0.9-11 d11/d12, when d11/d12 satisfies the condition, it is helpful for lens processing and lens assembly. Satisfies d11/d12 of 0.92-10.93.

When the focal length of the image pickup optical lens 10, the focal length of each lens, the on-axis distance from the image side surface to the object side surface of the relevant lens, and the on-axis thickness satisfy the above relation, the image pickup optical lens 10 can have high performance, and the design requirements of large aperture and ultra-thin can be satisfied.

The curvature radius of the object side surface of the first lens L1 is R1, the curvature radius of the image side surface of the first lens L1 is R2, -5.68 ≦ (R1+ R2)/(R1-R2) ≦ -0.28, the shape of the first lens L1 is defined, and when the conditional expression is within the defined range, the shape of the first lens L1 is favorably and reasonably controlled, so that the first lens L1 can effectively correct the system spherical aberration. Preferably, it satisfies-3.55 ≦ (R1+ R2)/(R1-R2) ≦ -0.35.

The on-axis thickness of the first lens L1 is d1, the total optical length of the shooting optical lens is TTL, and the following relational expression is satisfied: d1/TTL is more than or equal to 0.04 and less than or equal to 0.18, and ultra-thinning is favorably realized within the range specified by the conditional expression. Preferably, 0.07. ltoreq. d 1/TTL. ltoreq.0.14 is satisfied.

The focal length of the second lens L2 is f2, and the series relation is satisfied: 14.42 ≦ f2/f ≦ -1.24, provided that the second lens element L2 has negative refractive power, and that correction of aberrations of the optical system is facilitated by controlling the negative power of the second lens element L2 within a reasonable range. Preferably, it satisfies-9.02. ltoreq. f 2/f. ltoreq-1.55.

The curvature radius of the object side surface of the second lens L2 is R3, the curvature radius of the image side surface of the second lens L2 is R4, the curvature radius of-0.93 (R3+ R4)/(R3-R4) is less than or equal to 13.90, and the shape of the second lens L2 is defined, so that the deflection degree of light rays passing through the lens can be alleviated, and the aberration can be effectively reduced. Preferably, it satisfies-0.58 ≦ (R3+ R4)/(R3-R4). ltoreq.11.12.

The on-axis thickness of the second lens L2 is d3, the total optical length of the shooting optical lens is TTL, and the following relational expression is satisfied: d3/TTL is more than or equal to 0.02 and less than or equal to 0.08, and ultra-thinning is facilitated. Preferably, 0.03. ltoreq. d 3/TTL. ltoreq.0.06 is satisfied.

Defining the focal length f of the entire image pickup optical lens 10 and the focal length f3 of the third lens L3, the following relations are satisfied: -6.60 ≦ f3/f ≦ -1.31, and said third lens element L3 has negative refractive power within the conditional ranges, which specifies the ratio of the focal length of the third lens element to the total focal length of the system, which allows better imaging quality and lower sensitivity by a reasonable distribution of focal lengths. Preferably-4.12. ltoreq. f 3/f. ltoreq-1.63.

The on-axis thickness of the third lens L3 is d5, the total optical length of the shooting optical lens is TTL, and the following relational expression is satisfied: d5/TTL is more than or equal to 0.02 and less than or equal to 0.05, and ultra-thinning is favorably realized within the specified range of the conditional expression. Preferably, 0.03. ltoreq. d 5/TTL. ltoreq.0.04 is satisfied.

The focal length of the fourth lens L4 is f4, and the series relation is satisfied: -171.86 ≦ f4/f ≦ 23.11, which specifies the ratio of the focal length of the fourth lens L4 to the overall focal length. When the optical power is within the specified range, the system has better imaging quality and lower sensitivity through reasonable distribution of the optical power. Preferably, it satisfies-107.41 ≦ f4/f ≦ 18.49.

The curvature radius of the object side surface of the fourth lens L4 is R7, the curvature radius of the image side surface of the fourth lens L4 is R8, -5.29 ≤ (R7+ R8)/(R7-R8) ≤ 14.49, and the shape of the fourth lens L4 is defined, so that the problem of aberration of off-axis angularity and the like can be corrected with the development of ultra-thin and wide-angle angles within the conditional expression range. Preferably, it satisfies-3.31 ≦ (R7+ R8)/(R7-R8). ltoreq.11.60.

The on-axis thickness of the fourth lens L4 is d7, the total optical length of the shooting optical lens is TTL, and the following relational expression is satisfied: d7/TTL is more than or equal to 0.03 and less than or equal to 0.15, and ultra-thinning is facilitated. Preferably, 0.05. ltoreq. d 7/TTL. ltoreq.0.12 is satisfied.

The focal length of the fifth lens L5 is f5, and the series relation is satisfied: 5.35 ≦ f5/f ≦ 5.57, and the ratio of the focal length of the fifth lens to the total focal length of the system is specified within the range specified by the conditional expression, so that the system has better imaging quality and lower sensitivity through reasonable distribution of the focal lengths. Preferably, it satisfies-3.34. ltoreq. f 5/f. ltoreq.4.45.

The curvature radius of the object side surface of the fifth lens L5 is R9, the curvature radius of the image side surface of the fifth lens L5 is R10, -2.76 ≤ (R9+ R10)/(R9-R10) ≤ 4.68, and the shape of the fifth lens L5 is defined, so that the problem of aberration of the off-axis angle can be corrected with the development of the ultra-thin and wide-angle in the conditional expression range. Preferably, it satisfies-1.73 ≦ (R9+ R10)/(R9-R10). ltoreq.3.74.

The on-axis thickness of the fifth lens L5 is d9, the total optical length of the shooting optical lens is TTL, and the following relational expression is satisfied: d9/TTL is more than or equal to 0.02 and less than or equal to 0.10, and ultra-thinning is favorably realized within the range of conditional expressions. Preferably, 0.04. ltoreq. d 9/TTL. ltoreq.0.08 is satisfied.

The focal length of the sixth lens L6 is f6, and the series relation is satisfied: f6/f 1.64 of 20.52 and less, and the ratio of the focal length of the sixth lens L6 to the overall focal length is defined. Within the specified range, the sixth lens element L6 has negative refractive power, so that the system has better imaging quality and lower sensitivity. Preferably, it satisfies-12.82. ltoreq. f 6/f. ltoreq-2.05.

The curvature radius of the object side surface of the sixth lens L6 is R11, the curvature radius of the image side surface of the sixth lens L6 is R12, -15.18 ≦ (R11+ R12)/(R11-R12) ≦ -1.56, and the shape of the sixth lens L6 is defined, so that it is advantageous to correct the problems such as the aberration of the off-axis angle with the development of the ultra-thin and wide-angle in the conditional expression range. Preferably, it satisfies-9.49 ≦ (R11+ R12)/(R11-R12). ltoreq.1.95.

The on-axis thickness of the sixth lens L6 is d11, the total optical length of the imaging optical lens is TTL, and the following relational expression is satisfied: d11/TTL is more than or equal to 0.02 and less than or equal to 0.07, and ultra-thinning is facilitated. Preferably, 0.04. ltoreq. d 11/TTL. ltoreq.0.05 is satisfied.

The focal length of the seventh lens L7 is f7, and the series relation is satisfied: f7/f is not less than 0.45 and not more than 1.47, and the ratio of the focal length of the seventh lens L7 to the overall focal length is specified. Within the specified range, the seventh lens element L7 has positive refractive power, so that the system has better imaging quality and lower sensitivity. Preferably, 0.73. ltoreq. f 7/f. ltoreq.1.18 is satisfied.

The curvature radius R13 of the object side surface of the seventh lens L7 and the curvature radius R14 of the image side surface of the seventh lens L7 are defined, and the following relations are satisfied: 4.18 ≦ (R13+ R14)/(R13-R14) ≦ -0.67, and defines the shape of the seventh lens to help reduce the degree of light deflection and reduce aberration. Preferably, it satisfies-2.61. ltoreq. (R13+ R14)/(R13-R14). ltoreq.0.84.

The on-axis thickness of the seventh lens L7 is d13, the total optical length of the imaging optical lens is TTL, and the following relational expression is satisfied: d13/TTL is more than or equal to 0.04 and less than or equal to 0.16, and ultra-thinning is facilitated. Preferably, 0.07. ltoreq. d 13/TTL. ltoreq.0.13 is satisfied.

The focal length of the eighth lens L8 is f8, and the series relation is satisfied: f8/f is not less than 1.62 and not more than-0.48, and the ratio of the focal length of the eighth lens L8 to the overall focal length is specified. When the refractive power of the eighth lens element L8 is within the predetermined range, the lens element is beneficial to reducing the system aberration, and is beneficial to the development of ultra-thin and wide-angle lenses. Preferably, it satisfies-1.02. ltoreq. f 8/f. ltoreq-0.60.

The curvature radius of the object side surface of the eighth lens L8 is R15, the curvature radius of the image side surface of the eighth lens L8 is R16, and the (R15+ R16)/(R15-R16) is not more than 0.45 in a ratio of 0.01, and the shape of the eighth lens is defined, so that the deflection degree of light rays passing through the lens can be alleviated and the aberration can be effectively reduced within the range defined by the conditional expression. Preferably, 0.01. ltoreq. (R15+ R16)/(R15-R16). ltoreq.0.36 is satisfied.

The on-axis thickness of the eighth lens L8 is d15, the total optical length of the shooting optical lens is TTL, and the following relational expression is satisfied: d15/TTL is more than or equal to 0.03 and less than or equal to 0.09, and ultra-thinning is facilitated. Preferably, 0.05. ltoreq. d 15/TTL. ltoreq.0.07 is satisfied.

In this embodiment, the combined focal length of the first lens L1 and the second lens L2 is defined as f12, and the following relation is satisfied: f12/f is not less than 0.46 and not more than 3.48, and within the range of the conditional expression, the aberration and distortion of the image pickup optical lens 10 can be eliminated, and the back focal length of the image pickup optical lens 10 can be suppressed, so as to keep the miniaturization of the image lens system. Preferably, 0.73. ltoreq. f 12/f. ltoreq.2.78.

In this embodiment, the total optical length TTL of the image pickup optical lens 10 is less than or equal to 9.41 mm, which is beneficial to achieving ultra-thinning. Preferably, the total optical length TTL is less than or equal to 8.98 millimeters.

In the present embodiment, the F-number (Fno) of the imaging optical lens 10 is 1.65 or less. The large aperture is large, and the imaging performance is good. Preferably, the F-number is less than or equal to 1.62.

With such a design, the total optical length TTL of the entire imaging optical lens 10 can be made as short as possible, and the characteristic of miniaturization can be maintained.

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, curvature radius, on-axis thickness, position of reverse curvature and position of stagnation point is mm.

TTL: optical length (on-axis distance from the object side surface of the 1 st lens L1 to the image forming surface) in mm;

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: the radius of curvature of the optical surface and the radius of curvature of the lens as the center;

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

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

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

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

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

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

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

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

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

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

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

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

r13: a radius of curvature of the object side surface of the seventh lens L7;

r14: a radius of curvature of the image-side surface of the seventh lens L7;

r15: a radius of curvature of the object side surface of the eighth lens L8;

r16: a radius of curvature of the image-side surface of the eighth lens L8;

r17: radius of curvature of the object side of the optical filter GF;

r18: the radius of curvature of the image-side surface of the optical filter GF;

d: an on-axis thickness of the lenses and an 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: an on-axis distance from the image-side surface of the sixth lens L6 to the object-side surface of the seventh lens L7;

d 13: the on-axis thickness of the seventh lens L7;

d 14: the on-axis distance from the image-side surface of the seventh lens L7 to the object-side surface of the optical filter GF;

d 15: the on-axis thickness of the eighth lens L8;

d 16: the on-axis distance from the image-side surface of the eighth lens L8 to the object-side surface of the optical filter GF;

d 17: on-axis thickness of the optical filter GF;

d 18: the on-axis distance from the image side surface of the optical filter GF to the image surface;

nd: the refractive index of the d-line;

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;

nd 7: the refractive index of the d-line of the seventh lens L7;

nd 8: the refractive index of the d-line of the eighth lens L8;

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;

v 7: abbe number of the seventh lens L7;

v8: abbe number of the eighth lens L8;

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 ]

Wherein k is a conic coefficient, and A4, A6, A8, A10, A12, A14, A16, A18, A20 are aspheric coefficients.

IH: image height

y＝(x²/R)/[1+{1-(k+1)(x²/R²)}^1/2]+A4x⁴+A6x⁶+A8x⁸+A10x¹⁰+A12x¹²+A14x¹⁴+A16x¹⁶+A18x¹⁸+A20x²⁰(1)

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

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, P6R1 and P6R2 represent the object-side surface and the image-side surface of the sixth lens L6, and P7R1 and P7R2 represent the object-side surface and the image-side surface of the seventh lens L7, respectively. P8R1 and P8R2 represent the object-side surface and the image-side surface of the eighth lens L8, 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 ]

	Number of points of inflection	Position of reverse curvature 1	Position of reverse curvature 2	Position of reverse curvature 3
					P1R1
P1R2
					P2R1
P2R2	2	1.525	1.735
					P3R1	2	1.065	1.765
P3R2
					P4R1	2	0.495	1.875
P4R2	2	0.265	2.085
					P5R1	3	0.375	2.085	2.425
P5R2	2	2.125	2.635
					P6R1	2	1.815	2.685
P6R2	2	1.995	2.905
					P7R1	3	1.445	3.305	4.475
P7R2	3	1.675	4.325	4.695
					P8R1	2	2.265	5.185
P8R2	3	0.875	4.685	5.425

[ TABLE 4 ]

	Number of stagnation points	Location of stagnation 1	Location of stagnation 2	Location of stagnation 3
					P1R1
P1R2
					P2R1
P2R2
					P3R1
P3R2
					P4R1	1	0.825
P4R2	1	0.455
					P5R1	1	0.675
P5R2
					P6R1
P6R2
					P7R1
	3	2.335	4.405	4.525
					P7R2	1	2.375
P8R1	1	4.655
					P8R2	1	1.825

Fig. 2 and 3 are schematic diagrams showing axial aberrations and chromatic aberration of magnification of light having wavelengths of 656nm, 588nm, 546nm, 486nm, and 436nm passing through the imaging optical lens 10 according to the first embodiment, respectively. Fig. 4 is a schematic view showing the field curvature and distortion of light having a wavelength of 546nm after passing through the imaging optical lens 10 according to the first embodiment, where the field curvature S in fig. 4 is the field curvature in the sagittal direction, and T is the field curvature in the tangential direction.

Table 13 shown later shows values of various numerical values in examples 1, 2, and 3 corresponding to the parameters specified in the conditional expressions.

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

In the present embodiment, the imaging optical lens has an entrance pupil diameter of 4.220mm, a full field height of 6.200mm, a diagonal field angle of 83.70 °, a large aperture, a wide angle, and a high profile, 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.

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 ]

	Number of points of inflection	Position of reverse curvature 1	Position of reverse curvature 2	Position of reverse curvature 3
					P1R1
P1R2
		3	0.425	0.505	1.995
P2R1						1	1.975
	P2R2	2	1.135	1.755
P3R1						2	0.685	1.765
	P3R2	2	0.975	1.365
P4R1						2	1.455	2.005
	P4R2
P5R1
		3	0.395	2.145	2.265
P5R2						3	0.415	2.125	2.465
	P6R1	3	0.675	0.955	2.585
P6R2						1	2.645
	P7R1	2	1.295	3.065
P7R2						2	1.555	3.845
	P8R1	1	2.395
P8R2						1	0.815

[ TABLE 8 ]

	Number of stagnation points	Location of stagnation 1
			P1R1
P1R2
			P2R1
P2R2
			P3R1	1	1.155
P3R2
			P4R1	1	1.865
P4R2
			P5R1	1	0.735
P5R2	1	0.805
			P6R1
P6R2
			P7R1	1	2.145
P7R2	1	2.465
			P8R1
P8R2	1	1.585

Fig. 6 and 7 are schematic diagrams showing axial aberrations and chromatic aberration of magnification of light having wavelengths of 656nm, 588nm, 546nm, 486nm, and 436nm passing through the imaging optical lens 20 according to the second embodiment, respectively. Fig. 8 is a schematic view showing curvature of field and distortion of light having a wavelength of 546nm after passing through the imaging optical lens 20 according to the second embodiment.

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

In the present embodiment, the imaging optical lens has an entrance pupil diameter of 4.209mm, a full field height of 6.200mm, a diagonal field angle of 83.80 °, a large aperture, a wide angle, and a high profile, 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.

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 ]

	Number of points of inflection	Position of reverse curvature 1	Position of reverse curvature 2	Position of reverse curvature 3	Position of reverse curve 4
						P1R1
P1R2	1	0.275
						P2R1	1	0.195
P2R2	2	0.985	1.825
						P3R1	3	1.445	1.545	1.875
P3R2
						P4R1	2	0.405	1.815
P4R2	2	0.375	2.125
						P5R1	3	0.515	2.135	2.305
P5R2	3	0.215	2.015	2.555
						P6R1	4	1.965	2.695	2.855	2.965
P6R2	2	2.105	2.935
						P7R1	3	1.305	3.185	4.465
P7R2	2	1.475	4.775
						P8R1	2	2.205	4.975
P8R2	3	0.875	4.605	5.365

[ TABLE 12 ]

	Number of stagnation points	Location of stagnation 1	Location of stagnation 2
				P1R1
P1R2	1	0.555
				P2R1	1	0.365
P2R2	2	1.715	1.895
				P3R1
P3R2
				P4R1	1	0.645
P4R2	1	0.615
				P5R1	1	0.875
P5R2	1	0.355
				P6R1
P6R2	2	2.855	3.015
				P7R1	1	2.245
P7R2	1	2.175
				P8R1	2	4.285	5.425
P8R2	1	1.835

Fig. 10 and 11 are schematic diagrams showing axial aberrations and chromatic aberration of magnification of light having wavelengths of 656nm, 588nm, 546nm, 486nm, and 436nm passing through the imaging optical lens 30 according to the third embodiment, respectively. Fig. 12 is a schematic view showing curvature of field and distortion of light having a wavelength of 546nm after passing through the imaging optical lens 30 according to the third embodiment.

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 system of the present embodiment satisfies the above conditional expressions.

In the present embodiment, the imaging optical lens has an entrance pupil diameter of 4.210mm, a full field height of 6.200mm, a diagonal field angle of 83.80 °, a large aperture, a wide angle, and a high profile, and has excellent optical characteristics with on-axis and off-axis chromatic aberration sufficiently corrected.

[ TABLE 13 ]

Parameter and condition formula	Example 1	Example 2	Example 3
				f1/f	1.00	1.76	0.64
(R5+R6)/(R5-R6)	6.93	3.93	2.43
				d3/d4	3.76	1.12	2.94
f	6.752	6.735	6.735
				f1	6.756	11.853	4.310
f2	-48.70	-38.46	-12.56
				f3	-22.265	-14.423	-13.198
f4	104.017	7.137	-578.727
				f5	18.817	-18.010	25.002
f6	-16.645	-69.101	-18.424
				f7	6.630	6.120	6.258
f8	-4.855	-5.472	-4.869
				f12	7.618	15.604	6.129
Fno	1.60	1.60	1.60

Fno is the F-number of the diaphragm of the image pickup optical lens.

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, in order from an object side to an image side, comprising: a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, a seventh lens, and an eighth lens;

0.6≤f1/f≤1.8；

f2≤0mm；

2≤(R5+R6)/(R5-R6)≤7；

1.1≤d3/d4≤3.8。

2. the imaging optical lens according to claim 1, wherein an on-axis thickness of the sixth lens is d11, an on-axis distance from an image-side surface of the sixth lens to an object-side surface of the seventh lens is d12, and the following relational expression is satisfied:

0.9≤d11/d12≤11。

3. the image-capturing optical lens of claim 1, wherein the radius of curvature of the object-side surface of the first lens is R1, the radius of curvature of the image-side surface of the first lens is R2, and 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:

-5.68≤(R1+R2)/(R1-R2)≤-0.28；

0.04≤d1/TTL≤0.18。

4. the imaging optical lens of claim 1, wherein the radius of curvature of the object-side surface of the second lens element is R3, the radius of curvature of the image-side surface of the second lens element is R4, the total optical length of the imaging optical lens is TTL, and the following relationships are satisfied:

-14.42≤f2/f≤-1.24；

-0.93≤(R3+R4)/(R3-R4)≤13.90；

0.02≤d3/TTL≤0.08。

5. the image-capturing optical lens of claim 1, wherein the focal length of the third lens is f3, the on-axis thickness of the third lens is d5, the total optical length of the image-capturing optical lens is TTL, and the following relationship is satisfied:

-6.60≤f3/f≤-1.31；

0.02≤d5/TTL≤0.05。

6. the image-taking optical lens according to claim 1, wherein the fourth lens has a focal length f4, a radius of curvature of an object-side surface of the fourth lens is R7, a radius of curvature of an image-side surface of the fourth lens is R8, and an on-axis thickness d7, the image-taking optical lens has an optical total length TTL, and satisfies the following relationship:

-171.86≤f4/f≤23.11；

-5.29≤(R7+R8)/(R7-R8)≤14.49；

0.03≤d7/TTL≤0.15。

7. the image-capturing optical lens unit according to claim 1, wherein the focal length of the fifth lens element is f5, the radius of curvature of the object-side surface of the fifth lens element is R9, the radius of curvature of the image-side surface of the fifth lens element is R10, and the on-axis thickness of the fifth lens element is d9, the optical total length of the image-capturing optical lens unit is TTL, and the following relationship is satisfied:

-5.35≤f5/f≤5.57；

-2.76≤(R9+R10)/(R9-R10)≤4.68；

0.02≤d9/TTL≤0.10。

8. the image-capturing optical lens unit according to claim 1, wherein the sixth lens element has a focal length f6, a radius of curvature of the object-side surface of the sixth lens element is R11, a radius of curvature of the image-side surface of the sixth lens element is R12, and the image-capturing optical lens unit has a total optical length TTL satisfying the following relationship:

-20.52≤f6/f≤-1.64；

-15.18≤(R11+R12)/(R11-R12)≤-1.56；

0.02≤d11/TTL≤0.07。

9. the imaging optical lens of claim 1, wherein the seventh lens has a focal length of f7, an on-axis radius of curvature of an object-side surface of the seventh lens is R13, an on-axis radius of curvature of an image-side surface of the seventh lens is R14, an on-axis thickness of the seventh lens is d13, and the imaging optical lens has a total optical length of TTL and satisfies the following relationship:

0.45≤f7/f≤1.47；

-4.18≤(R13+R14)/(R13-R14)≤-0.67；

0.04≤d13/TTL≤0.16。

10. the image-taking optical lens according to claim 1, wherein the eighth lens element has a focal length f8, a radius of curvature of an object-side surface of the eighth lens element is R15, a radius of curvature of an image-side surface of the eighth lens element is R16, and an on-axis thickness d15, and the image-taking optical lens has an optical total length TTL satisfying the following relationship:

-1.62≤f8/f≤-0.48；

0.01≤(R15+R16)/(R15-R16)≤0.45；

0.03≤d15/TTL≤0.09。