CN110749980B

CN110749980B - Image pickup optical lens

Info

Publication number: CN110749980B
Application number: CN201911154523.0A
Authority: CN
Inventors: 郭雨桐
Original assignee: Chengrui Optics Changzhou Co Ltd
Current assignee: Chengrui Optics Changzhou Co Ltd
Priority date: 2019-11-22
Filing date: 2019-11-22
Publication date: 2021-11-02
Anticipated expiration: 2039-11-22
Also published as: WO2021097914A1; CN110749980A

Abstract

The invention provides a photographic optical lens, which sequentially comprises a first lens with negative refractive power, a second lens with positive refractive power, a third lens with negative refractive power, a fourth lens with positive refractive power and a fifth lens with negative refractive power from an object side to an image side, and the following relational expressions are satisfied: f2/f is more than or equal to 1.10 and less than or equal to 2.00; 1.20-3.00 of (R7+ R8)/(R7-R8); d7/d8 is more than or equal to 5.00 and less than or equal to 8.00; R5/R6 is more than or equal to 8.00 and less than or equal to 50.00. The imaging optical lens has good optical performance and also meets the design requirements of wide angle and ultra-thinness.

Description

Image pickup optical lens

[ technical field ] A method for producing a semiconductor device

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 of the invention ]

With the development of imaging technology, imaging optical lenses are widely used in various electronic products, such as smart phones and digital cameras. In order to be portable, people are increasingly pursuing the lightness and thinness of electronic products, and therefore, the small-sized image pickup optical lens with good imaging quality is the mainstream of the current market.

The camera optical lens on the traditional electronic product mostly adopts a four-piece type, five-piece type, six-piece type or even seven-piece type lens structure, however, along with the increase of diversified demands of users, because the focal power distribution and the lens shape setting of the existing lens structure are insufficient, the wide angle and the ultra-thinness of the camera optical lens are still insufficient.

Therefore, it is necessary to provide an imaging optical lens having excellent optical performance and satisfying design requirements for a wide angle and a slim profile.

[ summary of the invention ]

The invention aims to provide an imaging optical lens, aiming at solving the problems of insufficient wide angle and ultrathin of the traditional imaging optical lens.

The technical scheme of the invention is as follows: an imaging optical lens includes, in order from an object side to an image side: a first lens element with negative refractive power, a second lens element with positive refractive power, a third lens element with negative refractive power, a fourth lens element with positive refractive power, and a fifth lens element with negative refractive power; wherein a focal length of the entire imaging optical lens is f, a focal length of the second lens is f2, 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, 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, an on-axis thickness of the fourth lens is d7, an 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 relationships are satisfied: f2/f is more than or equal to 1.10 and less than or equal to 2.00; 1.20-3.00 of (R7+ R8)/(R7-R8); d7/d8 is more than or equal to 5.00 and less than or equal to 8.00; R5/R6 is more than or equal to 8.00 and less than or equal to 50.00.

Preferably, the focal length of the third lens is f3, and the following relation is satisfied: f3/f is more than or equal to-5.00 and less than or equal to-2.50.

Preferably, 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, and the following relation is satisfied: 2.00-5.00 (R9+ R10)/(R9-R10).

Preferably, the focal length of the first lens is f1, the curvature radius of the object-side surface of the first lens is R1, the curvature radius 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 pickup optical lens is TTL, and the following relationships are satisfied: f1/f is more than or equal to-18.86 and less than or equal to-1.96; -1.37 ≤ (R1+ R2)/(R1-R2) 2.81; d1/TTL is more than or equal to 0.03 and less than or equal to 0.10.

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, and the total optical length of the imaging optical lens system is TTL and satisfies the following relationship: (R3+ R4)/(R3-R4) is not more than 0.12 and not more than 0.83; d3/TTL is more than or equal to 0.05 and less than or equal to 0.22.

Preferably, the on-axis thickness of the third lens is d5, the total optical length of the image pickup optical lens is TTL, and the following relation is satisfied: (R5+ R6)/(R5-R6) is not more than 0.52 and not more than 1.93; 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 total optical length of the image pickup optical lens is TTL, and the following relationship is satisfied: f4/f is more than or equal to 0.43 and less than or equal to 1.50; d7/TTL is more than or equal to 0.09 and less than or equal to 0.28.

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 not less than 5.62 and not more than-0.76; d9/TTL is more than or equal to 0.04 and less than or equal to 0.18.

Preferably, the total optical length of the image pickup optical lens is TTL, the image height of the image pickup optical lens is IH, and the following relationship is satisfied: TTL/IH is less than or equal to 1.74.

Preferably, the field angle of the imaging optical lens is FOV, and satisfies the following relation: the FOV is more than or equal to 115 degrees.

The invention has the beneficial effects that: the imaging optical lens provided by the invention has good optical performance and meets the design requirements of wide angle and ultra-thinness.

[ description of the 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 view of axial aberrations of the image-taking optical lens shown in 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 shown in 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 view of axial aberrations of the image pickup optical lens shown in 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 shown in 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 ] embodiments

The invention is further described with reference to the following figures and embodiments.

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 fig. 1 to 4, the present invention provides an image pickup optical lens 10 according to a first embodiment. In fig. 1, the left side is an object side, the right side is an image side, and the imaging optical lens assembly 10 mainly includes five lenses, namely, a first lens L1, a stop S1, a second lens L2, a third lens L3, a fourth lens L4 and a fifth lens L5 in order from the object side to the image side. A glass flat GF is disposed between the fifth lens L5 and the image plane Si, and the glass flat GF may be a glass cover plate or an optical filter.

In this embodiment, the first lens element L1 has negative refractive power; the second lens element L2 has positive refractive power; the third lens element L3 has negative refractive power; the fourth lens element L4 has positive refractive power; the fifth lens element L5 has negative refractive power.

It is defined that the focal length of the entire imaging optical lens 10 is f, the focal length of the second lens L2 is f2, 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, the radius of curvature of the object-side surface of the fourth lens L4 is R7, the radius of curvature of the image-side surface of the fourth lens L4 is R8, the on-axis thickness of the fourth lens L4 is 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 is d8, and the following relationships are satisfied:

1.10≤f2/f≤2.00 (1)

1.20≤(R7+R8)/(R7-R8)≤3.00 (2)

5.00≤d7/d8≤8.00 (3)

8.00≤R5/R6≤50.00 (4)

the conditional expression (1) specifies the ratio of the focal length f2 of the second lens L2 to the total focal length f of the system, which can effectively balance the spherical aberration and the field curvature of the system. Preferably, 1.11. ltoreq. f 2/f. ltoreq.1.97 is satisfied.

The conditional expression (2) defines the shape of the fourth lens L4, and contributes to improvement of the optical system performance within the range of the conditional expression (2). Preferably, 1.21 ≦ (R7+ R8)/(R7-R8) ≦ 2.96.

The conditional expression (3) specifies the ratio of the on-axis thickness d7 of the fourth lens L4 to the on-axis distance d8 from the image-side surface of the fourth lens L4 to the object-side surface of the fifth lens L5, and contributes to the reduction in the total length of the optical system within the range of the conditional expression (3) to achieve the effect of making the optical system ultra-thin. Preferably, it satisfies 5.01. ltoreq. d7/d 8. ltoreq.7.98.

The shape of the third lens L3 is defined by the conditional expression (4), and the degree of deflection of the light passing through the lens can be reduced within the range defined by the conditional expression (4), thereby effectively reducing the aberration. Preferably, 8.01. ltoreq. R5/R6. ltoreq.49.99 is satisfied.

In the present embodiment, the focal length of the third lens L3 is f3, and the following relational expression is satisfied: -5.00 ≦ f3/f ≦ -2.50, which specifies the ratio of the focal length f3 of the third lens L3 to the total focal length f of the system, and by a reasonable distribution of the focal lengths, the system has better imaging quality and lower sensitivity. Preferably, it satisfies-4.99. ltoreq. f 3/f. ltoreq-2.53.

In the present embodiment, the curvature radius of the object-side surface of the fifth lens L5 is defined as R9, and the curvature radius of the image-side surface of the fifth lens L5 is defined as R10, and the following relational expressions are satisfied: 2.00 ≦ (R9+ R10)/(R9-R10) ≦ 5.00, defines the shape of the fifth lens L5, and can effectively correct aberrations generated by the front four lenses of the optical system. Preferably, 2.02 ≦ (R9+ R10)/(R9-R10) ≦ 4.98. In the present embodiment, the focal length of the first lens L1 is defined as f1, and the following relation is satisfied: 18.86. ltoreq. f 1/f. ltoreq.1.96, which specifies the negative refractive power of the first lens element L1. If the negative refractive power exceeds the upper limit value, the lens is made thinner, but the negative refractive power of the first lens element L1 is too strong, which makes it difficult to correct aberrations and the like, and makes it difficult to make the lens wider. On the other hand, if the refractive power exceeds the lower limit value, the negative refractive power of the first lens element L1 becomes too weak, and the lens barrel becomes difficult to be made thinner. Preferably, it satisfies-11.79. ltoreq. f 1/f. ltoreq-2.45.

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, and the following relations are satisfied: 1.37 ≦ (R1+ R2)/(R1-R2) ≦ 2.81, and the shape of the first lens L1 is controlled appropriately so that the first lens L1 can correct the system spherical aberration effectively. Preferably, it satisfies-0.85 ≦ (R1+ R2)/(R1-R2) ≦ 2.25.

The on-axis thickness of the first lens L1 is d1, the total optical length of the imaging optical lens is TTL, and the following relational expression is satisfied: d1/TTL is more than or equal to 0.03 and less than or equal to 0.10, and ultra-thinning is facilitated. Preferably, 0.05. ltoreq. d 1/TTL. ltoreq.0.08 is satisfied.

In the present embodiment, the curvature radius of the object-side surface of the second lens L2 is R3, and the curvature radius of the image-side surface of the second lens L2 is R4, and the following relationships are satisfied: the second lens L2 is defined in a shape of (R3+ R4)/(R3-R4) of 0.12 to 0.83, 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, 0.18. ltoreq. R3+ R4)/(R3-R4. ltoreq.0.67 is satisfied.

The on-axis thickness of the second lens L2 is d3, and satisfies the following relation: d3/TTL is more than or equal to 0.05 and less than or equal to 0.22, and ultra-thinning is facilitated. Preferably, 0.08. ltoreq. d 3/TTL. ltoreq.0.17 is satisfied.

In the present embodiment, the radius of curvature of the object-side surface of the third lens L3 is R5, and the radius of curvature of the image-side surface of the third lens L3 is R6, and the following relational expressions are satisfied: the ratio of (R5+ R6)/(R5-R6) is not less than 0.52 and not more than 1.93, the shape of the third lens L3 can be effectively controlled, the molding of the third lens L3 is facilitated, and the poor molding and stress generation caused by the overlarge surface curvature of the third lens L3 are avoided. Preferably, 0.83 ≦ (R5+ R6)/(R5-R6) ≦ 1.54.

The on-axis thickness of the third lens L3 is d5, and satisfies the following relation: d5/TTL is more than or equal to 0.02 and less than or equal to 0.08, and ultra-thinning is facilitated. Preferably, 0.04. ltoreq. d 5/TTL. ltoreq.0.06 is satisfied.

In the present embodiment, the focal length of the fourth lens L4 is f4, and the following relationship is satisfied: f4/f is more than or equal to 0.43 and less than or equal to 1.50, and the system has better imaging quality and lower sensitivity through reasonable distribution of the focal power. Preferably, 0.69. ltoreq. f 4/f. ltoreq.1.20 is satisfied.

The on-axis thickness of the fourth lens L4 is d7, and satisfies the following relation: d7/TTL is more than or equal to 0.09 and less than or equal to 0.28, and ultra-thinning is facilitated. Preferably, 0.14. ltoreq. d 7/TTL. ltoreq.0.23 is satisfied.

In the present embodiment, the focal length f5 of the fifth lens L5 satisfies the following relationship: f5/f is less than or equal to-0.76, 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-3.51. ltoreq. f 5/f. ltoreq-0.95.

The fifth lens L5 has an on-axis thickness d9, and satisfies the following relationship: d9/TTL is more than or equal to 0.02 and less than or equal to 0.08, and ultra-thinning is facilitated. Preferably, 0.07 ≦ d9/TTL ≦ 0.15.

In addition, in the imaging optical lens 10 provided in the present embodiment, the surface of each lens can be an aspheric surface, which is easy to be made into a shape other than a spherical surface, so as to obtain more control variables for reducing the aberration and further reducing the number of lenses used, thereby effectively reducing the total length of the imaging optical lens 10.

It is to be noted that since the first lens L1, the second lens L2, the third lens L3, the fourth lens L4, and the fifth lens L5 have the structure and the parameter relationship as described above, the image-taking optical lens 10 can reasonably distribute the power, the interval, and the shape of each lens, and thus correct various kinds of aberrations.

In this embodiment, the total optical length TTL of the image pickup optical lens 10 is less than or equal to 4.39 mm, which is beneficial to achieving ultra-thinning. Preferably, the total optical length TTL is less than or equal to 4.19 millimeters.

In the present embodiment, the number of apertures F of the imaging optical lens 10 is 2.30 or less. The large aperture is large, and the imaging performance is good. Preferably, the F-number is less than or equal to 2.25.

In the present embodiment, the ratio between the total optical length TTL and the image height IH of the imaging optical lens 10 is less than or equal to 1.74, so that the requirement for ultra-thinness is met.

In the present embodiment, the field angle FOV of the imaging optical lens 10 is not less than 115 °, and a wide angle is achieved.

In this way, the imaging optical lens 10 can satisfy design requirements for a large aperture and an ultra-thin structure while having good optical imaging performance.

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 plane) 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 shows the object-side and image-side radii of curvature R, the on-axis thicknesses of the respective lenses, the distance d between the adjacent lenses, the refractive index nd, and the abbe number ν d of the first lens L1 to the fifth lens L5 constituting the imaging optical lens 10 according to the first embodiment of the present invention. In the present embodiment, R and d are both expressed in units of millimeters (mm).

[ TABLE 1 ]

The meanings of the symbols in the above table are as follows.

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

s1: an aperture;

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

r2 radius of curvature of image side surface of first lens L1;

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

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

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

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

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

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

r9 radius of curvature of object-side surface of fifth lens L5;

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

r11 radius of curvature of object side of glass plate GF;

r12 radius of curvature of image side of glass plate GF;

d: the on-axis thickness of each lens or the on-axis distance between two adjacent lenses;

d0 on-axis distance from 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: the on-axis distance from the image-side surface of the fifth lens L5 to the object-side surface of the glass plate GF;

d 11: on-axis thickness of glass flat GF;

d 12: the axial distance from the image side surface of the glass flat GF to the image surface Si;

nd: a refractive index;

nd 1: the refractive index of the first lens L1;

nd 2: the refractive index of the second lens L2;

nd 3: refractive index of the third lens L3;

nd 4: refractive index of the fourth lens L4;

nd 5: the refractive index of the fifth lens L5;

ndg: refractive index of glass plate GF;

vd is 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;

vg: abbe number of glass sheet 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 ]

In table 2, k is a conic coefficient, and a4, a6, A8, a10, a12, a14, a16, a18, a20 are aspherical 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 embodiment of the present invention. P1R1 and P2R2 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, and P4R1 and P4R2 represent the object-side surface and the image-side surface of the fourth lens L4, respectively. P5R1 and P5R2 represent the object-side surface and the image-side surface of the fifth lens L5, 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	2	0.155	0.865
P1R2	1	0.615
					P2R1	1	0.345
P2R2	0
					P3R1	1	0.045
P3R2	3	0.305	0.615	0.785
					P4R1	2	0.175	0.695
P4R2	3	0.665	0.905	1.175
					P5R1	2	0.395	1.295
P5R2	2	0.435	1.785

[ TABLE 4 ]

	Number of stagnation points	Location of stagnation 1	Location of stagnation 2
				P1R1	1	0.265
P1R2	0
				P2R1	0
P2R2	0
				P3R1	1	0.075
P3R2	0
				P4R1	2	0.325	0.855
P4R2	0
				P5R1	1	0.765
P5R2	1	1.165

Table 13 below also lists values corresponding to various parameters in the first embodiment and parameters already defined in the conditional expressions.

Fig. 2 and 3 are schematic diagrams showing axial aberrations and chromatic aberration of magnification of light having wavelengths of 650nm, 610nm, 555nm, 510nm, 470nm, and 435nm, respectively, passing through the imaging optical lens 10. Fig. 4 is a schematic view showing curvature of field and distortion of light having a wavelength of 555nm after passing through the imaging optical lens 10. The field curvature S in fig. 4 is a field curvature in the sagittal direction, and T is a field curvature in the meridional direction.

In the present embodiment, the imaging optical lens 10 has an entrance pupil diameter of 0.746mm, a full field image height of 2.300mm, a diagonal field angle of 115.00 °, a wide angle, and a thin profile, and has excellent optical characteristics.

(second embodiment)

Fig. 5 is a schematic structural diagram of the imaging optical lens 20 in the second embodiment, which is basically the same as the first embodiment, and the meanings of symbols in the following list are also the same as those in the first embodiment, so that the same parts are not described herein again, and only different points are listed 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 inflected point and stagnation point design data of each lens in the imaging optical lens 20.

[ TABLE 7 ]

[ TABLE 8 ]

	Number of stagnation points	Location of stagnation 1	Location of standing pointDevice 2
				P1R1	1	0.285
P1R2	0
				P2R1	1	0.385
P2R2	0
				P3R1	1	0.055
P3R2	1	0.605
				P4R1	2	0.305	0.885
P4R2	0
				P5R1	1	0.635
P5R2	1	1.195

Table 13 below also lists values corresponding to various parameters in the second embodiment and parameters already defined in the conditional expressions.

Fig. 6 and 7 are schematic diagrams showing axial aberrations and chromatic aberration of magnification of light having wavelengths of 650nm, 610nm, 555nm, 510nm, 470nm, and 435nm passing through the imaging optical lens 20, respectively. Fig. 8 is a schematic view showing curvature of field and distortion of light having a wavelength of 555nm after passing through the imaging optical lens 20. The field curvature S in fig. 8 is a field curvature in the sagittal direction, and T is a field curvature in the tangential direction.

In the present embodiment, the imaging optical lens 10 has an entrance pupil diameter of 0.731mm, a full field image height of 2.300mm, a diagonal field angle of 116.20 °, a wide angle, and a thin profile, and has excellent optical characteristics.

(third embodiment):

fig. 9 is a schematic structural diagram of an imaging optical lens 30 according to a third embodiment, which is basically the same as the first embodiment, and the meanings of symbols in the following list are also the same as those in the first embodiment, so that the same parts are not described again, and only different points are listed 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 inflected point and stagnation point design data of each lens in the imaging optical lens 30.

[ TABLE 11 ]

	Number of points of inflection	Position of reverse curvature 1	Position of reverse curvature 2	Position of reverse curvature 3
					P1R1	1	0.825
P1R2	1	0.645
					P2R1	1	0.265
P2R2	0
					P3R1	3	0.045	0.535	0.555
P3R2	1	0.215
					P4R1	3	0.415	0.475	0.715
P4R2	1	0.725
					P5R1	2	0.385	1.305
P5R2	1	0.395

[ TABLE 12 ]

	Number of stagnation points	Location of stagnation 1
			P1R1	0
P1R2	0
			P2R1	1	0.375
P2R2	0
			P3R1	1	0.065
P3R2	1	0.345
			P4R1	0
P4R2	0
			P5R1	1	0.825
P5R2	1	1.025

Table 13 below also lists values corresponding to various parameters in the third embodiment and parameters already defined in the conditional expressions.

Fig. 10 and 11 are schematic diagrams showing axial aberrations and chromatic aberration of magnification of light having wavelengths of 650nm, 610nm, 555nm, 510nm, 470nm, and 435nm, respectively, passing through the imaging optical lens 30. Fig. 12 is a schematic view showing curvature of field and distortion of light having a wavelength of 555nm after passing through the imaging optical lens 30. The field curvature S in fig. 12 is a field curvature in the sagittal direction, and T is a field curvature in the tangential direction.

In the present embodiment, the imaging optical lens 10 has an entrance pupil diameter of 0.748mm, a full field image height of 2.300mm, a diagonal field angle of 115.20 °, a wide angle, and a thin profile, and has excellent optical characteristics.

Table 13 below lists the values of the conditional expressions in the first embodiment, the second embodiment, and the third embodiment, and values of other relevant parameters according to the conditional expressions.

[ TABLE 13 ]

Conditional expressions and parameters	Example 1	Example 2	Example 3
				f2/f	1.118	1.109	1.939
(R7+R8)/(R7-R8)	1.269	1.207	2.921
				d7/d8	6.174	7.968	5.008
R5/R6	22.665	49.985	8.010
				f	1.663	1.631	1.669
f1	-4.897	-5.383	-15.736
				f2	1.860	1.808	3.237
f3	-4.389	-4.161	-8.328
				f4	1.608	1.411	1.672
f5	-2.572	-1.853	-4.692
				f12	2.385	2.190	3.909
Fno	2.229	2.231	2.231

While the foregoing is directed to embodiments of the present invention, it will be understood by those skilled in the art that various changes may be made without departing from the spirit and scope of the invention.

Claims

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

wherein a focal length of the entire imaging optical lens is f, a focal length of the second lens is f2, 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, 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, an on-axis thickness of the fourth lens is d7, and an 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 relationships are satisfied:

1.10≤f2/f≤2.00；

1.20≤(R7+R8)/(R7-R8)≤3.00；

5.00≤d7/d8≤8.00；

8.00≤R5/R6≤50.00。

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

-5.00≤f3/f≤-2.50。

3. the imaging optical lens according to claim 1, wherein a radius of curvature of an object-side surface of the fifth lens element is R9, a radius of curvature of an image-side surface of the fifth lens element is R10, and the following relational expression is satisfied:

2.00≤(R9+R10)/(R9-R10)≤5.00。

4. the imaging optical lens of claim 1, wherein the first lens has a focal length of f1, a radius of curvature of an object-side surface of the first lens is R1, a radius of curvature of an image-side surface of the first lens is R2, and an on-axis thickness of the first lens is d1, the imaging optical lens has a total optical length of TTL, and satisfies the following relationship:

-18.86≤f1/f≤-1.96；

-1.37≤(R1+R2)/(R1-R2)≤2.81；

0.03≤d1/TTL≤0.10。

5. 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:

0.12≤(R3+R4)/(R3-R4)≤0.83；

0.05≤d3/TTL≤0.22。

6. a photographic optical lens according to claim 1, wherein the on-axis thickness of the third lens element is d5, the total optical length of the photographic optical lens is TTL, and the following relationship is satisfied:

0.52≤(R5+R6)/(R5-R6)≤1.93；

0.02≤d5/TTL≤0.08。

7. a camera optical lens according to claim 1, wherein the focal length of the fourth lens element is f4, the total optical length of the camera optical lens is TTL, and the following relationship is satisfied:

0.43≤f4/f≤1.50；

0.09≤d7/TTL≤0.28。

8. 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:

-5.62≤f5/f≤-0.76；

0.04≤d9/TTL≤0.18。

9. a camera optical lens according to claim 1, wherein the total optical length of the camera optical lens is TTL, the image height of the camera optical lens is IH, and the following relationship is satisfied: TTL/IH is less than or equal to 1.74.

10. The imaging optical lens according to claim 1, wherein a field angle of the imaging optical lens is FOV, and satisfies the following relation:

FOV≥115°。