CN111077643B

CN111077643B - Image pickup optical lens

Info

Publication number: CN111077643B
Application number: CN201911335879.4A
Authority: CN
Inventors: 孙雯
Original assignee: Chengrui Optics Changzhou Co Ltd
Current assignee: Chengrui Optics Changzhou Co Ltd
Priority date: 2019-12-23
Filing date: 2019-12-23
Publication date: 2021-09-28
Anticipated expiration: 2039-12-23
Also published as: CN111077643A

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; 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 fifth lens is R9, the curvature radius of the image-side surface of the fifth lens is R10, the on-axis thickness of the fourth lens is d7, the on-axis distance from the image-side surface of the fourth lens to the object-side surface of the fifth lens is d8, and the following relational expressions are satisfied: f1/f is more than or equal to 0.78 and less than or equal to 1.90; f2 is less than or equal to 0; (R9+ R10)/(R9-R10) is not more than 0.10 and not more than 0.85; d7/d8 is more than or equal to 4.00 and less than or equal to 20.00. The camera optical lens provided by the invention has good optical performance, and meets the design requirements of large aperture, wide angle and ultra-thinness.

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 in a form of being excellent in function, light, thin, short and small, so that 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 three-piece, four-piece, or even five-piece or six-piece lens structures. However, with the development of technology and the increasing demand of diversification of users, under the condition that the pixel area of the photosensitive device is continuously reduced and the requirement of the system for the imaging quality is continuously improved, an eight-piece lens structure gradually appears in the lens design, although a common eight-piece lens has good optical performance, the focal power, the lens pitch and the lens shape setting still have certain irrationality, so that the design requirements of large aperture and ultra-thinness cannot be met while the lens structure has 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 has good optical performance and satisfies design requirements for a large aperture and an ultra-thin structure.

To solve the above-mentioned problems, an embodiment of the present invention provides an imaging optical lens assembly, which includes eight lenses, in order 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;

the focal length of the image pickup 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 fifth lens is R9, the curvature radius of the image side surface of the fifth lens is R10, the on-axis thickness of the fourth lens is d7, the on-axis distance from the image side surface of the fourth lens to the object side surface of the fifth lens is d8, and the following relational expression is satisfied: f1/f is more than or equal to 0.78 and less than or equal to 1.90; f2 is less than or equal to 0; (R9+ R10)/(R9-R10) is not more than 0.10 and not more than 0.85; d7/d8 is more than or equal to 4.00 and less than or equal to 20.00.

Preferably, the focal length of the third lens is f3, and the following relation is satisfied: f3/f is more than or equal to 1.00 and less than or equal to 7.00.

Preferably, the curvature radius of the object-side surface of the first lens element is R1, the curvature radius of the image-side surface of the first lens element is R2, the on-axis thickness of the first lens element is d1, and the total optical length of the imaging optical lens system is TTL and satisfies the following relationship: 11.83 is less than or equal to (R1+ R2)/(R1-R2) is less than or equal to-1.16; d1/TTL is more than or equal to 0.03 and less than or equal to 0.20.

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, the on-axis thickness of the second lens element is d3, the total optical length of the imaging optical lens system is TTL, and the following relationships are satisfied: f2/f is not less than 4.48 and not more than-1.30; (R3+ R4)/(R3-R4) is not more than 0.94 and not more than 10.31; d3/TTL is more than or equal to 0.02 and less than or equal to 0.05.

Preferably, the curvature radius of the object-side surface of the third lens element is R5, the curvature radius of the image-side surface of the third lens element is R6, the on-axis thickness of the third lens element is d5, and the total optical length of the imaging optical lens system is TTL and satisfies the following relationship: -14.82 ≤ (R5+ R6)/(R5-R6) ≤ 1.31; d5/TTL is more than or equal to 0.02 and less than or equal to 0.16.

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, the total optical length of the imaging optical lens system is TTL, and the following relationships are satisfied: f4/f is more than or equal to minus 10.40 and less than or equal to minus 2.31; -2.81 ≤ (R7+ R8)/(R7-R8) 1.22; d7/TTL is more than or equal to 0.02 and less than or equal to 0.15.

Preferably, the focal length of the fifth lens is f5, the on-axis thickness of the fifth lens is d9, the total optical length of the imaging optical lens is TTL, and the following relation is satisfied: f5/f is more than or equal to 1.88 and less than or equal to 14.50; d9/TTL is more than or equal to 0.02 and less than or equal to 0.06.

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, the on-axis thickness of the sixth lens element is d11, the total optical length of the imaging optical lens system is TTL, and the following relationships are satisfied: f6/f is more than or equal to 1.82 and less than or equal to 27.93; (R11+ R12)/(R11-R12) is not more than 0.06 and not more than 4.53; d11/TTL is more than or equal to 0.03 and less than or equal to 0.08.

Preferably, the focal length of the seventh lens element is f7, the curvature radius of the object-side surface of the seventh lens element is R13, the 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: -368.12 ≦ f7/f ≦ 7.85; 15.95-15.78 (R13+ R14)/(R13-R14) -107.79; d13/TTL is more than or equal to 0.03 and less than or equal to 0.08.

Preferably, the focal length of the eighth lens element is f8, the radius of curvature of the object-side surface of the eighth lens element is R15, the radius of curvature of the image-side surface of the eighth lens element is R16, 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: f8/f is more than or equal to-1.59 and less than or equal to-0.48; -2.38 ≤ (R15+ R16)/(R15-R16) ≤ 0.67; d15/TTL is more than or equal to 0.03 and less than or equal to 0.09.

The invention has the beneficial effects that: the imaging optical lens according to the present invention has excellent optical characteristics, has a large aperture and is made thin, and is particularly suitable for a mobile phone imaging lens unit and a WEB imaging lens which are constituted by imaging 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 needed to be used in the description of the embodiments are 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 of FIG. 9;

fig. 13 is a schematic configuration diagram of an imaging optical lens according to a fourth embodiment of the present invention;

fig. 14 is a schematic view of axial aberrations of the image pickup optical lens shown in fig. 13;

fig. 15 is a schematic diagram of chromatic aberration of magnification of the imaging optical lens shown in fig. 13;

fig. 16 is a schematic view of curvature of field and distortion of the imaging optical lens shown in fig. 13.

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.

The first lens element L1 with positive refractive power, the second lens element L2 with negative refractive power, the third lens element L3 with positive refractive power, the fourth lens element L4 with negative refractive power, the fifth lens element L5 with positive refractive power, the sixth lens element L6 with positive refractive power and the eighth lens element L8 with negative refractive power.

In the present embodiment, the focal length of the entire imaging optical lens 10 is defined as f, and the focal length of the first lens L1 is defined as f1, and the following relational expression is satisfied: f1/f is more than or equal to 0.78 and less than or equal to 1.90, the ratio of the focal length of the first lens to the total focal length is specified, and the total length of the system can be reduced within a condition range.

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

The curvature radius of the object side surface of the fifth lens L5 is defined as R9, the curvature radius of the image side surface of the fifth lens L5 is defined as R10, and the following relational expressions are satisfied: 0.10 ≦ (R9+ R10)/(R9-R10) ≦ 0.85, and defines the shape of the fifth lens to help reduce the degree of light deflection and reduce aberration. Preferably, 0.11. ltoreq. (R9+ R10)/(R9-R10). ltoreq.0.83 is satisfied.

Defining the on-axis thickness of the fourth lens L4 as d7, and the on-axis distance from the image-side surface of the fourth lens L4 to the object-side surface of the fifth lens L5 as d8, the following relationships are satisfied: 4.00-d 7/d 8-20.00, when d7/d8 meets the condition, the lens processing and lens assembly are facilitated. Preferably, 4.21 ≦ d7/d8 ≦ 19.64 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: f3/f is more than or equal to 1.00 and less than or equal to 7.00, the ratio of the focal length of the third lens to the total focal length is specified, aberration correction is facilitated within a condition range, and the image quality of an image plane is improved. Preferably, 1.02. ltoreq. f 3/f. ltoreq.6.89 is satisfied.

The curvature radius of the object side surface of the first lens L1 is defined as R1, the curvature radius of the image side surface of the first lens L1 is defined as R2, and the following relational expressions are satisfied: 11.83 ≦ (R1+ R2)/(R1-R2) ≦ -1.16, and the shape of the first lens L1 is appropriately controlled so that the first lens L1 can effectively correct the system spherical aberration, preferably, satisfying-7.39 ≦ (R1+ R2)/(R1-R2) ≦ -1.45.

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 relationship is satisfied: d1/TTL is more than or equal to 0.03 and less than or equal to 0.20, and ultra-thinning is favorably realized within the range of conditional expressions. Preferably, 0.05. ltoreq. d 1/TTL. ltoreq.0.16 is satisfied.

Defining the focal length f of the entire image pickup optical lens 10 and the focal length f2 of the second lens L2, the following relations are satisfied: 4.48 ≦ f2/f ≦ -1.30, which is advantageous for correcting aberrations of the optical system by controlling the negative power of the second lens L2 in a reasonable range. Preferably, it satisfies-2.80. ltoreq. f 2/f. ltoreq-1.63.

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, and the following relational expression is satisfied: the second lens L2 is defined in a shape of (R3+ R4)/(R3-R4) of 0.94 or more and 10.31 or less, and when the second lens L2 is within the range, the problem of chromatic aberration on the axis is favorably corrected as the lens is made to be ultra-thin and wide-angle. Preferably, 1.51 ≦ (R3+ R4)/(R3-R4) ≦ 8.25.

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 0.05, and ultra-thinning is facilitated in the condition formula range. Preferably, 0.03. ltoreq. d 3/TTL. ltoreq.0.04 is satisfied.

The curvature radius of the object side surface of the third lens L3 is defined as R5, the curvature radius of the image side surface of the third lens L3 is defined as R6, and the following relational expressions are satisfied: 14.82 ≦ (R5+ R6)/(R5-R6) ≦ -1.31, and defines the shape of the third lens, and within the range defined by the conditional expression, the degree of deflection of the light rays passing through the lens can be alleviated, and the aberration can be effectively reduced. Preferably, it satisfies-9.26 ≦ (R5+ R6)/(R5-R6). ltoreq.1.64.

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 0.02 and less than or equal to 0.16, and ultra-thinning is facilitated in the conditional expression range. Preferably, 0.03. ltoreq. d 5/TTL. ltoreq.0.13 is satisfied.

Defining the focal length f of the entire image pickup optical lens 10 and the focal length f4 of the fourth lens L4, the following relations are satisfied: f4/f is less than or equal to-2.31 and the ratio of the focal length of the fourth lens to the focal length of the system is specified, which contributes to the improvement of the performance of the optical system in a conditional range. Preferably, it satisfies-6.50. ltoreq. f 4/f. ltoreq-2.89.

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, and the following relational expression is satisfied: -2.81 ≦ (R7+ R8)/(R7-R8) ≦ 1.22, and the shape of the fourth lens L4 is defined, and when the shape is within the range, it is advantageous to correct the aberration of the off-axis angle and the like with the development of an ultra-thin and wide-angle view. Preferably, it satisfies-1.76. ltoreq. (R7+ R8)/(R7-R8). ltoreq.0.98.

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 0.02 and less than or equal to 0.15, and ultra-thinning is facilitated in the conditional expression range. Preferably, 0.03. ltoreq. d 7/TTL. ltoreq.0.12 is satisfied.

Defining the focal length of the entire image pickup optical lens 10 as f, and the focal length of the fifth lens L5 as f5, the following relations are satisfied: f5/f is more than or equal to 1.88 and less than or equal to 14.50, and the definition of the fifth lens L5 can effectively make the light ray angle of the camera lens smooth and reduce the tolerance sensitivity. Preferably, 3.01. ltoreq. f 5/f. ltoreq.11.60 is satisfied.

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 0.02 and less than or equal to 0.06, and ultra-thinning is facilitated in the conditional expression range. Preferably, 0.03. ltoreq. d 9/TTL. ltoreq.0.05 is satisfied.

Defining the focal length of the entire image pickup optical lens 10 as f and the focal length of the sixth lens L6 as f6, the following relationships are satisfied: 1.82 ≦ f6/f ≦ 27.93, which makes the system have better imaging quality and lower sensitivity by reasonable distribution of the optical power. Preferably, 2.92. ltoreq. f 6/f. ltoreq.22.34 is satisfied.

The curvature radius of the object-side surface of the sixth lens L6 is R11, and the curvature radius of the image-side surface of the sixth lens L6 is R12, and the following relations are satisfied: the (R11+ R12)/(R11-R12) is not more than 0.06 and not more than 4.53, and the shape of the sixth lens L6 is defined, and when the shape is within the condition range, the problem of aberration of off-axis picture angle is favorably corrected along with the development of ultra-thin wide-angle. Preferably, 0.09. ltoreq. (R11+ R12)/(R11-R12). ltoreq.3.62 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 0.08, and ultra-thinning is favorably realized within the range of conditional expressions. Preferably, 0.04. ltoreq. d 11/TTL. ltoreq.0.06 is satisfied.

Defining the focal length of the entire image pickup optical lens 10 as f and the focal length of the seventh lens L7 as f7, the following relations are satisfied: 368.12 ≦ f7/f ≦ 7.85, which allows better imaging quality and lower sensitivity of the system by a reasonable distribution of the powers. Preferably, it satisfies-230.08 ≦ f7/f ≦ 6.28.

The curvature radius of the object side surface of the seventh lens L7 is R13, the curvature radius of the image side surface of the seventh lens L7 is R14, and the following relational expression is satisfied: 15.95 ≦ (R13+ R14)/(R13-R14) ≦ 107.79, and the shape of the seventh lens L7 is specified, and when the conditions are within the range, it is advantageous to correct the aberration of the off-axis view angle and the like as the ultra-thin wide angle progresses. Preferably, it satisfies-9.97 ≦ (R13+ R14)/(R13-R14). ltoreq.86.23.

The on-axis thickness of the seventh lens L7 is d13, the total optical length of the imaging optical lens system 10 is TTL, and the following relationship is satisfied: d13/TTL is more than or equal to 0.03 and less than or equal to 0.08, and ultra-thinning is favorably realized within the range of conditional expressions. Preferably, 0.04. ltoreq. d 13/TTL. ltoreq.0.06 is satisfied.

Defining the focal length f of the entire image pickup optical lens 10 and the focal length f8 of the eighth lens L8, the following relations are satisfied: 1.59 ≦ f8/f ≦ -0.48, allowing better imaging quality and lower sensitivity of the system through reasonable distribution of optical power. Preferably, it satisfies-0.99. 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 following relational expression is satisfied: -2.38 ≦ (R15+ R16)/(R15-R16) ≦ -0.67, and the shape of the eighth lens L8 is specified, and when the conditions are within the range, it is advantageous to correct the aberration of the off-axis view angle as the ultra-thin wide angle progresses. Preferably, it satisfies-1.49 ≦ (R15+ R16)/(R15-R16). ltoreq.0.83.

The on-axis thickness of the eighth lens element L8 is d15, the total optical length of the imaging optical lens system 10 is TTL, and the following relationships are satisfied: d15/TTL is more than or equal to 0.03 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 15/TTL. ltoreq.0.07 is satisfied.

In the present embodiment, the image height of the entire imaging optical lens 10 is IH, and the total optical length of the imaging optical lens 10 is TTL, and the following conditional expressions are satisfied: TTL/IH is less than or equal to 1.22, thereby realizing ultra-thinning.

In the present embodiment, the number of apertures Fno of the imaging optical lens 10 is 1.95 or less.

The large aperture is large, and the imaging performance is good.

In the present embodiment, the field angle FOV of the imaging optical lens 10 is equal to or greater than 83 °, thereby achieving a wide angle.

When the above relationship is satisfied, the imaging optical lens 10 has good optical performance, and can satisfy design requirements of large aperture, wide angle and ultra-thinness; in accordance with the characteristics of the optical lens 10, the optical lens 10 is particularly suitable for a mobile phone camera lens module and a WEB camera lens which are configured by image pickup devices such as a high-pixel CCD and 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, curvature radius, on-axis thickness, position of reverse curvature and position of 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) in units of 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 image-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: an on-axis distance from the image-side surface of the seventh lens L7 to the object-side surface of the eighth lens L8;

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;

v 8: 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. Wherein 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, P7R1 and P7R2 represent the object-side surface and the image-side surface of the seventh lens L7, and 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	1	2.255
P1R2	1	2.155
					P2R1	1	2.205
P2R2	1	2.095
					P3R1	1	2.125
P3R2	1	1.895
					P4R1	0
P4R2	2	0.565	2.165
					P5R1	3	0.465	1.865	2.145
P5R2	2	1.895	2.415
					P6R1	2	0.645	2.655
P6R2	0
					P7R1	2	0.795	3.175
P7R2	2	0.875	3.955
					P8R1	1	2.495
P8R2	2	5.405	6.175

[ TABLE 4 ]

Fig. 2 and 3 are schematic diagrams showing axial aberrations and chromatic aberration of magnification of light having wavelengths of 656nm, 587nm, 546nm, 486nm, and 436nm passing through the imaging optical lens 10 according to the first embodiment. 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 17 shown later shows values corresponding to the parameters specified in the conditional expressions for the respective numerical values in examples 1, 2, 3, and 4.

As shown in table 17, the first embodiment satisfies each conditional expression.

In the present embodiment, the imaging optical lens has an entrance pupil diameter of 4.683mm, a full field height of 8.15mm, a diagonal field angle of 83.00 °, 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	1	2.305
P1R2	0
					P2R1	0
P2R2	0
					P3R1	0
P3R2	2	1.055	1.195
					P4R1	0
P4R2	1	2.125
					P5R1	3	0.125	1.895	2.365
P5R2	2	1.895	2.545
					P6R1	2	0.225	2.635
P6R2	0
					P7R1	3	1.105	3.275	4.605
P7R2	3	1.255	4.015	4.805
					P8R1	2	2.565	6.005
P8R2	2	5.285	6.255

[ TABLE 8 ]

	Number of stagnation points	Location of stagnation 1
			P1R1	0
P1R2	0
			P2R1	0
P2R2	0
			P3R1	0
P3R2	0
			P4R1	0
P4R2	0
			P5R1	1	0.205
P5R2	1	2.405
			P6R1	1	0.395
P6R2	0
			P7R1	1	1.915
P7R2	1	2.125
			P8R1	1	5.625
P8R2	0

Fig. 6 and 7 are schematic diagrams showing axial aberrations and chromatic aberration of magnification of light having wavelengths of 656nm, 587nm, 546nm, 486nm, and 436nm 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 546nm after passing through the imaging optical lens 20 according to the second embodiment.

As shown in table 17, the second embodiment satisfies each conditional expression.

(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
					P1R1	1	2.225
P1R2	0
					P2R1	0
P2R2	0
					P3R1	0
P3R2	2	1.065	1.545
					P4R1	0
P4R2	3	0.295	0.505	2.245
					P5R1	3	0.585	2.065	2.465
P5R2	2	1.955	2.665
					P6R1	3	0.595	2.735	3.065
P6R2	0
					P7R1	3	0.855	3.115	4.685
P7R2	3	1.005	3.855	4.905
					P8R1	2	2.385	6.065
P8R2	2	5.375	6.325

[ TABLE 12 ]

	Number of stagnation points	Location of stagnation 1
			P1R1	0
P1R2	0
			P2R1	0
P2R2	0
			P3R1	0
P3R2	0
			P4R1	0
P4R2	0
			P5R1	1	0.845
P5R2	0
			P6R1	1	0.885
P6R2	0
			P7R1	1	1.405
P7R2	1	1.645
			P8R1	1	5.595
P8R2	0

Fig. 10 and 11 are schematic diagrams showing axial aberration and chromatic aberration of magnification after light having wavelengths of 656nm, 587nm, 546nm, 486nm, and 436nm 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 546nm after passing through the imaging optical lens 30 according to the third embodiment.

Table 17 below shows the numerical values corresponding to the respective conditional expressions in the present embodiment in accordance with the conditional expressions. Obviously, the imaging optical system of the present embodiment satisfies the above conditional expressions.

(fourth embodiment)

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

Tables 13 and 14 show design data of the imaging optical lens 40 according to the fourth embodiment of the present invention.

[ TABLE 13 ]

Table 14 shows aspherical surface data of each lens in the imaging optical lens 40 according to the fourth embodiment of the present invention.

[ TABLE 14 ]

Tables 15 and 16 show the inflection points and the stagnation point design data of each lens in the imaging optical lens 40 according to the fourth embodiment of the present invention.

[ TABLE 15 ]

	Reverse bendingNumber of dots	Position of reverse curvature 1	Position of reverse curvature 2	Position of reverse curvature 3
					P1R1	1	2.255
P1R2	1	2.155
					P2R1	1	2.205
P2R2	1	2.095
					P3R1	1	2.125
P3R2	1	1.895
					P4R1	0
P4R2	2	0.565	2.165
					P5R1	3	0.465	1.865	2.145
P5R2	2	1.895	2.415
					P6R1	2	0.645	2.655
P6R2	0
					P7R1	2	0.795	3.175
P7R2	2	0.875	3.955
					P8R1	1	2.495
P8R2	2	5.405	6.175

[ TABLE 16 ]

	Number of stagnation points	Location of stagnation 1
			P1R1	0
P1R2	0
			P2R1	0
P2R2	0
			P3R1	0
P3R2	0
			P4R1	0
P4R2	1	0.875
			P5R1	1	0.725
P5R2	0
			P6R1	1	0.985
P6R2	0
			P7R1	1	1.315
P7R2	1	1.435
			P8R1	1	5.745
P8R2	0

Fig. 14 and 15 are schematic diagrams showing axial aberration and chromatic aberration of magnification of light having wavelengths of 656nm, 587nm, 546nm, 486nm, and 436nm passing through the imaging optical lens 40 according to the fourth embodiment. Fig. 16 is a schematic view showing curvature of field and distortion of light having a wavelength of 546nm after passing through the imaging optical lens 40 according to the fourth embodiment.

In the present embodiment, the imaging optical lens has an entrance pupil diameter of 4.683mm, a full field image height of 8.15mm, a diagonal field angle of 83.08 °, a wide angle, and a high profile, and has excellent optical characteristics with on-axis and off-axis chromatic aberration sufficiently corrected.

[ TABLE 17 ]

Parameter and condition formula	Example 1	Example 2	Example 3	Example 4
					f1/f	0.84	0.79	0.85	1.87
(R9+R10)/(R9-R10)	0.12	0.81	0.55	0.32
					d7/d8	4.12	10.12	19.28	7.32
f	9.039	9.039	9.039	9.040
					f1	7.569	7.116	7.673	16.856
f2	-19.207	-17.678	-20.252	-20.131
					f3	61.198	57.540	27.770	9.486
f4	-34.223	-46.984	-31.375	-33.631
					f5	37.711	87.379	33.997	37.740
f6	168.308	74.425	37.624	32.954
					f7	22.199	25.195	-1663.734	47.325
f8	-7.181	-6.874	-6.463	-6.490
					f12	11.010	10.451	10.937	60.967
Fno	1.93	1.93	1.93	1.93

Where Fno is the F-number of the diaphragm of the imaging 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 system comprising eight lens elements, in order 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;

the focal length of the image pickup 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 fifth lens is R9, the curvature radius of the image side surface of the fifth lens is R10, the on-axis thickness of the fourth lens is d7, the on-axis distance from the image side surface of the fourth lens to the object side surface of the fifth lens is d8, and the following relational expression is satisfied:

0.78≤f1/f≤1.90；

f2≤0；

0.10≤(R9+R10)/(R9-R10)≤0.85；

4.00≤d7/d8≤20.00。

2. the imaging optical lens according to claim 1, wherein the third lens has a focal length f3 and satisfies the following relationship:

1.00≤f3/f≤7.00。

3. the image-capturing optical lens unit according to claim 1, wherein the radius of curvature of the object-side surface of the first lens element is R1, the radius of curvature of the image-side surface of the first lens element is R2, the on-axis thickness of the first lens element is d1, the total optical length of the image-capturing optical lens unit is TTL, and the following relationships are satisfied:

-11.83≤(R1+R2)/(R1-R2)≤-1.16；

0.03≤d1/TTL≤0.20。

4. the image-capturing optical lens unit according to 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 on-axis thickness of the second lens element is d3, the total optical length of the image-capturing optical lens unit is TTL, and the following relationships are satisfied:

-4.48≤f2/f≤-1.30；

0.94≤(R3+R4)/(R3-R4)≤10.31；

0.02≤d3/TTL≤0.05。

5. the image-capturing optical lens unit according to claim 1, wherein the radius of curvature of the object-side surface of the third lens element is R5, the radius of curvature of the image-side surface of the third lens element is R6, the on-axis thickness of the third lens element is d5, the total optical length of the image-capturing optical lens unit is TTL, and the following relationships are satisfied:

-14.82≤(R5+R6)/(R5-R6)≤-1.31；

0.02≤d5/TTL≤0.16。

6. the image-capturing optical lens unit according to claim 1, wherein the fourth lens element has a focal length f4, a radius of curvature of the object-side surface of the fourth lens element is R7, a radius of curvature of the image-side surface of the fourth lens element is R8, and the image-capturing optical lens unit has a total optical length TTL satisfying the following relationships:

-10.40≤f4/f≤-2.31；

-2.81≤(R7+R8)/(R7-R8)≤1.22；

0.02≤d7/TTL≤0.15。

7. the image-capturing optical lens of claim 1, wherein the focal length of the fifth lens element is f5, the on-axis thickness of the fifth lens element is d9, the total optical length of the image-capturing optical lens is TTL, and the following relationship is satisfied:

1.88≤f5/f≤14.50；

0.02≤d9/TTL≤0.06。

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 an object-side surface of the sixth lens element is R11, a radius of curvature of an image-side surface of the sixth lens element is R12, an on-axis thickness of the sixth lens element is d11, an optical total length of the image-capturing optical lens unit is TTL, and the following relationship is satisfied:

1.82≤f6/f≤27.93；

0.06≤(R11+R12)/(R11-R12)≤4.53；

0.03≤d11/TTL≤0.08。

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

-368.12≤f7/f≤7.85；

-15.95≤(R13+R14)/(R13-R14)≤107.79；

0.03≤d13/TTL≤0.08。

10. the image-capturing optical lens unit 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, an on-axis thickness of the eighth lens element is d15, an optical total length of the image-capturing optical lens unit is TTL, and the following relationship is satisfied:

-1.59≤f8/f≤-0.48；

-2.38≤(R15+R16)/(R15-R16)≤-0.67；

0.03≤d15/TTL≤0.09。