CN111007629B

CN111007629B - Image pickup optical lens

Info

Publication number: CN111007629B
Application number: CN201911336768.5A
Authority: CN
Inventors: 陈佳
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: 2022-01-07
Anticipated expiration: 2039-12-23
Also published as: CN111007629A

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 sixth lens is R11, the curvature radius of the image-side surface of the sixth lens is R12, the on-axis thickness of the fifth lens is d9, the on-axis distance from the image-side surface of the fifth lens to the object-side surface of the sixth lens is d10, and the following relational expressions are satisfied: f1/f is more than or equal to 0.60 and less than or equal to 1.90; f2 is less than or equal to 0.00; less than or equal to 30.00 (R11+ R12)/(R11-R12) less than or equal to 6.00; d9/d10 is more than or equal to 3.30 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, the eight-piece lens structure gradually appears in the lens design, although the 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 lens structure can not meet the design requirements of wide angle and ultra-thinness while 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 has excellent optical performance and satisfies design requirements for a wide angle and an ultra-thin profile.

To solve the above-mentioned problems, an embodiment of the present invention provides an imaging optical lens, which includes 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 first lens element with positive refractive power, the second lens element with negative refractive power, the third lens element with positive refractive power, the sixth lens element with negative refractive power, the seventh lens element with positive refractive power, and the eighth lens element with negative refractive power;

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 sixth lens is R11, the curvature radius of the image side surface of the sixth lens is R12, the on-axis thickness of the fifth lens is d9, the on-axis distance from the image side surface of the fifth lens to the object side surface of the sixth lens is d10, and the following relational expression is satisfied: f1/f is more than or equal to 0.60 and less than or equal to 1.90; f5 is less than or equal to-82.54; less than or equal to 30.00 (R11+ R12)/(R11-R12) less than or equal to 6.00; d9/d10 is more than or equal to 3.30 and less than or equal to 20.00.

Preferably, the curvature radius of the object-side surface of the seventh lens is R13, the curvature radius of the image-side surface of the seventh lens is R14, and the following relation is satisfied: the ratio of (R13+ R14)/(R13-R14) is not less than 7.00 and not more than 3.50.

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: -5.32 ≤ (R1+ R2)/(R1-R2) ≤ 0.76; 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 4.19 and not more than-0.78; (R3+ R4)/(R3-R4) is not more than 1.01 and not more than 5.86; d3/TTL is more than or equal to 0.01 and less than or equal to 0.13.

Preferably, the focal length of the third lens element is f3, 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 pickup optical lens is TTL, and the following relationships are satisfied: f3/f is more than or equal to 0.91 and less than or equal to 4.47; 4.79 is less than or equal to (R5+ R6)/(R5-R6) is less than or equal to-1.07; d5/TTL is more than or equal to 0.02 and less than or equal to 0.08.

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 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: -70.30 ≤ f4/f ≤ 9.37; -33.87 (R7+ R8)/(R7-R8) is less than or equal to-0.17; d7/TTL is more than or equal to 0.01 and less than or equal to 0.07.

Preferably, 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 total optical length of the imaging optical lens system is TTL and satisfies the following relation: f5/f is not less than-10.94 and is not less than-3077.92; -269.35 (R9+ R10)/(R9-R10) is not more than 4.39; d9/TTL is more than or equal to 0.03 and less than or equal to 0.16.

Preferably, the focal length of the sixth lens element is f6, the on-axis thickness of the sixth lens element is d11, the total optical length of the imaging optical lens is TTL, and the following relationship is satisfied: f6/f is more than or equal to minus 80.25 and less than or equal to minus 6.11; d11/TTL is more than or equal to 0.01 and less than or equal to 0.05.

Preferably, the focal length of the seventh lens is f7, the on-axis thickness of the seventh lens is d13, the total optical length of the imaging optical lens is TTL, and the following relation is satisfied: f7/f is more than or equal to 1.18 and less than or equal to 3.73; d13/TTL is more than or equal to 0.06 and less than or equal to 0.21.

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: -2.63 ≤ f8/f ≤ 0.74; (R15+ R16)/(R15-R16) is not more than 0.80 and not more than 2.63; d15/TTL is more than or equal to 0.06 and less than or equal to 0.19.

The invention has the beneficial effects that: the imaging optical lens according to the present invention has excellent optical characteristics, has a wide angle of view and is made thinner, and is particularly suitable for a mobile phone imaging lens unit and a WEB imaging lens including an imaging element such as a high-pixel CCD or 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 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.

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 sixth lens element L6 with negative refractive power, the seventh lens element L7 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 0.60 and less than or equal to 1.90, the ratio of the focal length of the first lens to the total focal length of the system is specified, and the spherical aberration and the field curvature of the system can be effectively balanced. Preferably, 0.64. ltoreq. f 1/f. ltoreq.1.90 is satisfied.

Defining the focal length of the second lens L2 as f2, the following relation is satisfied: f2 is less than 0.00, and the positive and negative of the focal length of the second lens are regulated, so that the system has better imaging quality and lower sensitivity through reasonable distribution of the focal length.

The curvature radius of the object side surface of the sixth lens L6 is defined as R11, the curvature radius of the image side surface of the sixth lens L6 is defined as R12, and the following relational expressions are satisfied: 30.00 ≦ (R11+ R12)/(R11-R12) ≦ -6.00, and defines the shape of the sixth 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-29.97 ≦ (R11+ R12)/(R11-R12). ltoreq.6.03.

Defining the on-axis thickness of the fifth lens L5 as d9, and the on-axis distance from the image-side surface of the fifth lens L5 to the object-side surface of the sixth lens L6 as d10, the following relationships are satisfied: d9/d10 is more than or equal to 3.30 and less than or equal to 20.00, the ratio of the thickness of the fifth lens to the air space of the fifth and sixth lenses is specified, the total length of the optical system is favorably compressed within the range of the conditional expressions, and the ultrathin effect is realized. Preferably, 3.30. ltoreq. d9/d 10. ltoreq.19.98.

The curvature radius of the object side surface of the seventh lens L7 is defined as R13, the curvature radius of the image side surface of the seventh lens L7 is defined as R14, and the following relational expressions are satisfied: -7.00 ≦ (R13+ R14)/(R13-R14) ≦ -3.50, defining the shape of the seventh lens, contributing to the correction of the off-axis angular aberration within the conditional expression. Preferably, it satisfies-6.53 ≦ (R13+ R14)/(R13-R14). ltoreq.3.61.

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, the following relation-5.32 ≦ (R1+ R2)/(R1-R2) ≦ -0.76 is satisfied, 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, it is satisfied that-3.33 ≦ (R1+ R2)/(R1-R2) ≦ -0.94.

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: 4.19 ≦ f2/f ≦ -0.78, 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-2.62. ltoreq. f 2/f. ltoreq-0.98.

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 shape of the second lens L2 is defined to be not less than 1.01 (R3+ R4)/(R3-R4) and not more than 5.86, and the problem of chromatic aberration on the axis can be corrected favorably as the lens is developed to an ultra-thin wide angle within the range. Preferably, 1.61. ltoreq. (R3+ R4)/(R3-R4). ltoreq.4.69 is satisfied.

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 0.01 and less than or equal to 0.13, and ultra-thinning is facilitated in the condition formula range. Preferably, 0.02. ltoreq. d 3/TTL. ltoreq.0.10 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 0.91 and less than or equal to 4.47, and the system has better imaging quality and lower sensitivity through reasonable distribution of the focal power. Preferably, 1.46. ltoreq. f 3/f. ltoreq.3.58 is satisfied.

The curvature radius of the object side surface of the third lens L3 is R5, the curvature radius of the image side surface of the third lens L3 is R6, and the following relational expression is satisfied: 4.79 ≦ (R5+ R6)/(R5-R6) ≦ -1.07, and defines the shape of the third lens, and within the range defined by the conditional expression, the degree of deflection of the light passing through the lens can be alleviated, and the aberration can be effectively reduced. Preferably, it satisfies-2.99 ≦ (R5+ R6)/(R5-R6) ≦ -1.33.

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 0.08, and ultra-thinning is favorably realized within the range of conditional expressions. Preferably, 0.04. ltoreq. d 5/TTL. ltoreq.0.07 is satisfied.

Defining the focal length of the entire image pickup optical lens 10 as f, and the focal length of the fourth lens L4 as f4, the following relations are satisfied: 70.30 ≦ f4/f ≦ 9.37, which specifies the ratio of the focal length of the fourth lens to the focal length of the system, contributing to the improvement of the optical system performance within the conditional expression range. Preferably, it satisfies-43.94. ltoreq. f 4/f. ltoreq.7.50.

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: -33.87 ≦ (R7+ R8)/(R7-R8) ≦ -0.17, and the shape of the fourth lens L4 is specified, which is advantageous for correcting the aberration of the off-axis angle and the like with the development of an ultra-thin wide angle when in the range. Preferably, it satisfies-21.17 ≦ (R7+ R8)/(R7-R8) ≦ -0.21.

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 0.01 and less than or equal to 0.07, and ultra-thinning is favorably realized within the range of conditional expressions. Preferably, 0.02. ltoreq. d 7/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 fifth lens L5 as f5, the following relations are satisfied: f5/f is more than or equal to-3077.92 and less than or equal to-10.94, and the definition of the fifth lens L5 can effectively make the light angle of the camera lens smooth and reduce the tolerance sensitivity. Preferably, it satisfies-1923.70 ≦ f5/f ≦ -10.94.

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, and the following relational expression is satisfied: the shape of the fifth lens L5 is defined to be (R9+ R10)/(R9-R10) or less than 4.39 at 269.35 or less, and when the shape is within the range, the aberration of the off-axis picture angle is favorably corrected with the development of an ultra-thin wide angle. Preferably, it satisfies-168.34 ≦ (R9+ R10)/(R9-R10). ltoreq.3.52.

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 0.03 and less than or equal to 0.16, and ultra-thinning is favorably realized within the range of conditional expressions. Preferably, 0.05. ltoreq. d 9/TTL. ltoreq.0.13 is satisfied.

Defining the focal length f of the entire image pickup optical lens 10 and the focal length f6 of the sixth lens L6, the following relations are satisfied: 80.25 f6/f 6.11, and the system has better imaging quality and lower sensitivity through reasonable distribution of the optical power in the conditional range. Preferably, it satisfies-50.16. ltoreq. f 6/f. ltoreq-7.64.

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 0.01 and less than or equal to 0.05, and ultra-thinning is facilitated in the condition formula range. Preferably, 0.02. ltoreq. d 11/TTL. ltoreq.0.04 is satisfied.

Defining the focal length f of the entire image pickup optical lens 10 and the focal length f7 of the seventh lens L7, the following relations are satisfied: 1.18 ≦ f7/f ≦ 3.73, and the system has better imaging quality and lower sensitivity through reasonable distribution of the focal power within the conditional range. Preferably, 1.89. ltoreq. f 7/f. ltoreq.2.99 is satisfied.

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 0.06 and less than or equal to 0.21, and ultra-thinning is facilitated in the conditional expression range. Preferably, 0.10. ltoreq. d 13/TTL. ltoreq.0.17 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: 2.63 ≦ f8/f ≦ -0.74, making the system with better imaging quality and lower sensitivity by reasonable distribution of optical power. Preferably, it satisfies-1.65. ltoreq. f 8/f. ltoreq-0.93.

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: 0.80 to (R15+ R16)/(R15-R16) to 2.63, and the shape of the eighth lens L8 is specified, and when the conditions are within the range, problems such as aberration of off-axis picture angle can be corrected favorably with the development of ultra-thin wide-angle. Preferably, 1.28. ltoreq. (R15+ R16)/(R15-R16). ltoreq.2.11 is satisfied.

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 0.06 and less than or equal to 0.19, and ultra-thinning is facilitated in the conditional expression range. Preferably, 0.09. ltoreq. d 15/TTL. ltoreq.0.15 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 1.60, thereby being beneficial to realizing ultra-thinning.

In the present embodiment, the F-number Fno of the imaging optical lens 10 is 2.01 or less. The large aperture is large, and the imaging performance is good.

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	1.875
P1R2	1	1.425
					P2R1	0
P2R2	0
					P3R1	0
P3R2	2	0.505	1.545
					P4R1	0
P4R2	1	1.825
					P5R1	2	0.515	2.005
P5R2	1	0.435
					P6R1	2	1.785	2.405
P6R2	1	1.795
					P7R1	3	1.005	2.935	4.165
P7R2	1	1.215
					P8R1	2	0.405	2.485
P8R2	3	0.995	4.645	5.055

[ 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 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 3.773mm, a full field height of 6mm, a diagonal field angle of 76.20 °, 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	0
P1R2	2	0.675	0.745
					P2R1	1	1.695
P2R2	0
					P3R1	1	1.235
P3R2	1	0.585
					P4R1	1	1.685
P4R2	1	1.795
					P5R1	1	2.015
P5R2	1	1.945
					P6R1	2	1.095	2.375
P6R2	2	1.115	2.535
					P7R1	1	1.125
P7R2	2	1.375	4.315
					P8R1	3	0.425	2.455	4.755
P8R2	3	1.025	4.695	5.115

[ TABLE 8 ]

	Number of stagnation points	Location of stagnation 1	Location of stagnation 2
				P1R1	0
P1R2	0
				P2R1	0
P2R2	0
				P3R1	1	1.665
P3R2	1	1.195
				P4R1	0
P4R2	0
				P5R1	0
P5R2	0
				P6R1	2	2.075	2.565
P6R2	2	1.955	2.805
				P7R1	1	1.915
P7R2	1	2.385
				P8R1	2	0.745	4.125
P8R2	1	2.225

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 13, the second embodiment satisfies each conditional expression.

In the present embodiment, the imaging optical lens has an entrance pupil diameter of 3.881mm, a full field image height of 6mm, a diagonal field angle of 74.61 °, 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 ]

[ TABLE 12 ]

	Number of stagnation points	Location of stagnation 1	Location of stagnation 2
				P1R1	0
P1R2	0
				P2R1	1	1.505
P2R2	0
				P3R1	0
P3R2	2	1.035	1.725
				P4R1	1	1.115
P4R2	0
				P5R1	1	1.465
P5R2	1	0.745
				P6R1	2	1.935	2.345
P6R2	1	1.755
				P7R1	1	2.045
P7R2	1	2.585
				P8R1	2	0.815	4.195
P8R2	1	2.325

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 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 3.315mm, a full field height of 6mm, a diagonal field angle of 83.42 °, 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	0.68	0.92	1.90
f2	-8.88	-11.07	-13.90
				(R11+R12)/(R11-R12)	-6.07	-29.93	-10.69
d9/d10	3.30	19.96	8.32
				f	7.545	7.762	6.631
f1	5.153	7.119	12.565
				f3	22.486	18.001	12.117
f4	-56.934	-272.824	41.419
				f5	-82.543	-11945.400	41.429
f6	-69.171	-311.464	-103.127
				f7	17.844	18.419	16.499
f8	-8.964	-8.646	-8.728
				f12	9.451	13.687	48.582
Fno	2.00	2.00	2.00

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, 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 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 sixth lens is R11, the curvature radius of the image side surface of the sixth lens is R12, the on-axis thickness of the fifth lens is d9, the on-axis distance from the image side surface of the fifth lens to the object side surface of the sixth lens is d10, and the following relational expression is satisfied:

0.60≤f1/f≤1.90；

f5≤-82.54；

-30.00≤(R11+R12)/(R11-R12)≤-6.00；

3.30≤d9/d10≤20.00。

2. the imaging optical lens of claim 1, wherein the radius of curvature of the object-side surface of the seventh lens is R13, the radius of curvature of the image-side surface of the seventh lens is R14, and the following relationship is satisfied:

-7.00≤(R13+R14)/(R13-R14)≤-3.50。

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:

-5.32≤(R1+R2)/(R1-R2)≤-0.76；

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:

-4.19≤f2/f≤-0.78；

1.01≤(R3+R4)/(R3-R4)≤5.86；

0.01≤d3/TTL≤0.13。

5. the imaging optical lens of claim 1, wherein the third lens has a focal length of f3, a radius of curvature of an object-side surface of the third lens is R5, a radius of curvature of an image-side surface of the third lens is R6, an on-axis thickness of the third lens is d5, and the imaging optical lens has a total optical length of TTL and satisfies the following relationship:

0.91≤f3/f≤4.47；

-4.79≤(R5+R6)/(R5-R6)≤-1.07；

0.02≤d5/TTL≤0.08。

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 an object-side surface of the fourth lens element is R7, a radius of curvature of an image-side surface of the fourth lens element is R8, an on-axis thickness of the fourth lens element is d7, an optical total length of the image-capturing optical lens unit is TTL, and the following relationship is satisfied:

-70.30≤f4/f≤9.37；

-33.87≤(R7+R8)/(R7-R8)≤-0.17；

0.01≤d7/TTL≤0.07。

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, the total optical length of the image-capturing optical lens unit is TTL, and the following relationships are satisfied:

-3077.92≤f5/f≤-10.94；

-269.35≤(R9+R10)/(R9-R10)≤4.39；

0.03≤d9/TTL≤0.16。

8. the image-capturing optical lens unit according to claim 1, wherein the sixth lens element has a focal length f6, an on-axis thickness d11, a total optical length TTL, and the following relationships are satisfied:

-80.25≤f6/f≤-6.11；

0.01≤d11/TTL≤0.05。

9. the image-capturing optical lens of claim 1, wherein the seventh lens has a focal length f7, an on-axis thickness d13, a total optical length TTL, and the following relationship is satisfied:

1.18≤f7/f≤3.73；

0.06≤d13/TTL≤0.21。

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:

-2.63≤f8/f≤-0.74；

0.80≤(R15+R16)/(R15-R16)≤2.63；

0.06≤d15/TTL≤0.19。