Imaging optical lens

Abstract

To provide an imaging optical lens.SOLUTION: An imaging optical lens comprises, in order from the object side to the image side, a first lens, a second lens, and a third lens, wherein when a focal distance of the imaging optical lens is represented by f, a focal distance of the first lens is represented by f1, an axial distance between the image side face of the first lens L1 and the object side face of the second lens L2 is represented by d2, an optical length of the imaging optical lens is represented by TTL, an angle of view of the imaging optical lens is represented by FOV, a total visual field image height of the imaging optical lens is represented by IH, a radius of curvature of the object side face of the third lens is represented by R5, a radius of curvature of the image side face of the third lens is represented by R6, and a refractive index of the first lens is represented by n1, conditional expressions: 0.80≤f1 / f≤1.60, 0.14≤d2 / TTL≤0.22, 100.00≤(FOV×f) / H≤115.00, 1.40≤R5 / R6≤4.00, and 1.70≤n1≤2.10 are satisfied. The imaging optical lens has good optical performance, and low sensitivity, and can achieve distance medium and distant imaging.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to the technical field of optical lenses, and more particularly to an imaging optical lens that is applied to mobile terminal devices such as smartphones and digital cameras, and imaging devices such as monitors, PC lenses, and vehicle-mounted lenses. [Background technology]

[0002] In recent years, with the rapid development of the automobile industry, there is an increasing demand for driver identification, fatigued driving detection and dangerous behavior detection systems. Driver monitoring systems are mainly realized by on-board imaging optical lenses. In order to improve detection accuracy, imaging optical lenses with good imaging quality and low sensitivity have become the mainstream in the current market.

[0003] In order to obtain excellent imaging quality, with the development of technology and the increasing diversification needs of users, the pixel area of ​​the photosensitive element is shrinking and the system requirements for imaging quality are increasing. In order to obtain excellent imaging quality, a three-lens structure has gradually appeared in the lens design. Although the ordinary three-lens structure already has good optical performance, its refractive power, the distance between the lenses and the lens shape still have a certain degree of irrationality. Therefore, in the application of the driver monitoring system, even if the lens structure has good optical performance, it cannot simultaneously meet the design requirements of low sensitivity and long-distance imaging. Summary of the Invention [Problem to be solved by the invention]

[0004] In view of the above problems, an object of the present invention is to provide an imaging optical lens that has good optical performance, has low sensitivity, and can realize medium- to long-distance imaging. [Means for solving the problem]

[0005] In order to solve the above technical problem, an embodiment of the present invention provides an imaging optical lens, the imaging optical lens including, in order from an object side to an image side, a first lens, a second lens, and a third lens, When a focal length of the imaging optical lens is f, a focal length of the first lens is f1, an axial distance from the image side surface of the first lens L1 to the object side surface of the second lens L2 is d2, an optical length of the imaging optical lens is TTL, an angle of view of the imaging optical lens is FOV, a total field of view image height of the imaging optical lens is IH, a radius of curvature of the object side surface of the third lens is R5, a radius of curvature of the image side surface of the third lens is R6, and a refractive index of the first lens is n1, the following conditional formulas (1) to (5) are satisfied. 0.80≦f1 / f≦1.60 (1) 0.14≦d2 / TTL≦0.22 (2) 100.00≦(FOV×f) / IH≦115.00 (3) 1.40≦R5 / R6≦4.00 (4) 1.70≦n1≦2.10 (5)

[0006] Preferably, when the focal length of the second lens is f2 and the axial thickness of the second lens is d3, the following conditional expression (6) is satisfied. 1.50≦f2 / d3≦4.00 (6)

[0007] Preferably, when the radius of curvature of the object side surface of the second lens is R3 and the radius of curvature of the image side surface of the second lens is R4, the following conditional expression (7) is satisfied. 1.50≦R3 / R4≦5.00 (7)

[0008] It is preferable that, when the focal length of the third lens is f3, the following conditional expression (8) is satisfied: -1.20≦f3 / f≦-0.60 (8)

[0009] Preferably, the first lens has positive refractive power, an object side surface of the first lens is a convex surface in a paraxial direction, and an image side surface of the first lens is a concave surface in a paraxial direction, When the radius of curvature of the object side surface of the first lens is R1, the radius of curvature of the image side surface of the first lens is R2, and the axial thickness of the first lens is d1, the following conditional expressions (9) and (10) are satisfied. -126.25≦(R1+R2) / (R1-R2)≦-1.80 (9) 0.08≦d1 / TTL≦0.45 (10)

[0010] Preferably, the second lens has a positive refractive power, an object side surface of the second lens is a concave surface in a paraxial direction, and an image side surface of the second lens is a convex surface in a paraxial direction, When the focal length of the second lens is f2, the axial thickness of the second lens is d3, the radius of curvature of the object side surface of the second lens is R3, and the radius of curvature of the image side surface of the second lens is R4, the following conditional expressions (11) to (13) are satisfied. 0.23≦f2 / f≦1.61 (11) 0.75≦(R3+R4) / (R3-R4)≦7.43 (12) 0.09≦d3 / TTL≦0.36 (13)

[0011] Preferably, the third lens has negative refractive power, an object side surface of the third lens is a convex surface in a paraxial direction, and an image side surface of the third lens is a concave surface in a paraxial direction. When the axial thickness of the third lens is d5, the following conditional expressions (14) and (15) are satisfied. 0.83≦(R5+R6) / (R5-R6)≦8.91 (14) 0.02≦d5 / TTL≦0.12 (15)

[0012] It is preferable that, when a composite focal length of the first lens and the second lens is f12, the following conditional expression (16) is satisfied. 0.31≦f12 / f≦1.18 (16)

[0013] Preferably, when the aperture value of the imaging optical lens is FNO, the following conditional expression (17) is satisfied: FNO≦3.47 (17)

[0014] Preferably, the first lens is made of a glass material, and the second lens and the third lens are made of a plastic material. Effect of the Invention

[0015] The beneficial effects of the present invention are as follows: the imaging optical lens provided by the present invention has good optical performance, has low sensitivity and can realize medium to long distance imaging, and is particularly applicable to the on-vehicle imaging optical lens of the driver monitoring system. [Brief description of the drawings]

[0016] In order to more clearly explain the technical solutions of the embodiments of the present invention, the following briefly introduces drawings required for the embodiments. Obviously, the drawings described below are only some embodiments of the present invention, and those skilled in the art can further obtain other drawings based on these drawings without any creative work. [Figure 1] 1 is a schematic diagram showing a configuration of an imaging optical lens according to a first embodiment of the present invention. [Diagram 2] 2 is a schematic diagram showing the field curvature and distortion of the imaging optical lens shown in FIG. [Diagram 3] 2 is a schematic diagram showing chromatic aberration of magnification of the imaging optical lens shown in FIG. [Figure 4] 2 is a schematic diagram showing axial chromatic aberration of the imaging optical lens shown in FIG. [Diagram 5] FIG. 4 is a schematic diagram showing the configuration of an imaging optical lens according to a second embodiment of the present invention. [Figure 6] 6 is a schematic diagram showing the field curvature and distortion of the imaging optical lens shown in FIG. 5. [Figure 7] 6 is a schematic diagram showing chromatic aberration of magnification of the imaging optical lens shown in FIG. 5. [Figure 8] 6 is a schematic diagram showing the longitudinal chromatic aberration of the imaging optical lens shown in FIG. 5. [Figure 9] FIG. 11 is a schematic diagram showing the configuration of an imaging optical lens according to a third embodiment of the present invention. [Figure 10] 10A and 10B are schematic diagrams showing the field curvature and distortion of the imaging optical lens shown in FIG. [Figure 11] 10 is a schematic diagram showing chromatic aberration of magnification of the imaging optical lens shown in FIG. [Figure 12] 10 is a schematic diagram showing the longitudinal chromatic aberration of the imaging optical lens shown in FIG. [Figure 13] FIG. 11 is a schematic diagram showing the configuration of an imaging optical lens according to a fourth embodiment of the present invention. [Figure 14] 14 is a schematic diagram showing the field curvature and distortion of the imaging optical lens shown in FIG. 13. [Figure 15] 14 is a schematic diagram showing chromatic aberration of magnification of the imaging optical lens shown in FIG. 13. [Figure 16] 14 is a schematic diagram showing the longitudinal chromatic aberration of the imaging optical lens shown in FIG. 13. [Figure 17] FIG. 13 is a schematic diagram showing the configuration of an imaging optical lens according to a fifth embodiment of the present invention. [Figure 18] 18A to 18C are schematic diagrams showing the field curvature and distortion of the imaging optical lens shown in FIG. 17. [Figure 19] 18 is a schematic diagram showing chromatic aberration of magnification of the imaging optical lens shown in FIG. 17. [Figure 20] 18 is a schematic diagram showing the longitudinal chromatic aberration of the imaging optical lens shown in FIG. 17. [Figure 21] FIG. 2 is a schematic diagram showing a configuration of an imaging optical lens according to a comparative example of the present invention. [Figure 22] 22A to 22C are schematic diagrams showing the field curvature and distortion of the imaging optical lens shown in FIG. 21. [Figure 23] 22 is a schematic diagram showing chromatic aberration of magnification of the imaging optical lens shown in FIG. 21. [Figure 24] 22 is a schematic diagram showing the longitudinal chromatic aberration of the imaging optical lens shown in FIG. 21. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] In order to make the object, solution and advantages of the present invention clearer, the following describes each embodiment of the present invention in detail with reference to the drawings. It can be understood by those skilled in the art that many technical details are described in each embodiment of the present invention to better understand the present invention. However, although many technical details are given in each embodiment of the present invention to make the present invention well understood, it should be understood by those skilled in the art that the present invention can be realized without the existence of those technical details and various changes and modifications based on the following embodiments.

[0018] (First embodiment) As shown in Figs. 1 to 4, a first embodiment of the present invention provides an imaging optical lens 10. The imaging optical lens 10 includes a total of three lenses. Specifically, the imaging optical lens 10 includes, in order from the object side to the image side, a first lens L1, a second lens L2, and a third lens L3. An optical element such as an optical filter GF may be provided between the third lens L3 and the image plane Si. In this embodiment, two optical filters, a first optical filter GF1 and a second optical filter GF2, may be provided between the third lens L3 and the image plane Si.

[0019] In this embodiment, the first lens L1 is made of a glass material, the second lens L2 is made of a plastic material, and the third lens L3 is made of a plastic material. The lens materials are arranged rationally to ensure that the lenses have good optical performance. When the refractive index of the first lens L1 is n1, the conditional expression 1.70≦n1≦2.10 is satisfied. Using a glass material with a high refractive index as the first lens L1 is advantageous in reducing the tip diameter and improving the imaging quality.

[0020] In this embodiment, when the focal length of the imaging optical lens 10 is f and the focal length of the first lens L1 is f1, the conditional formula 0.80≦f1 / f≦1.60 is satisfied, thereby defining the ratio between the focal length f1 of the first lens L1 and the focal length f of the imaging optical lens 10. By appropriately allocating the optical focal length of the imaging optical lens 10 within the range defined by the conditional formula, the imaging optical lens 10 has good imaging quality and low sensitivity.

[0021] In this embodiment, when the axial distance from the image-side surface of the first lens L1 to the object-side surface of the second lens L2 is d2 and the optical length of the imaging optical lens 10 is TTL, the conditional formula 0.14≦d2 / TTL≦0.22 is satisfied, which specifies the ratio of the air space between the first lens L1 and the second lens L2 to the optical length of the imaging optical lens 10, and contributes to shortening the overall length of the optical system within the range of the conditional formula, thereby achieving the effect of making the optical system extremely thin.

[0022] In this embodiment, when the angle of view of the imaging optical lens 10 is FOV and the total field of view image height of the imaging optical lens 10 is IH, the conditional formula 100.00≦(FOV×f) / IH≦115.00 is satisfied, and both the angle of view FOV and the focal length f of the imaging optical lens 10 can be achieved within the range of the conditional formula, thereby enabling mid- to long-distance imaging to be realized.

[0023] In this embodiment, when 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, the conditional formula 1.40≦R5 / R6≦4.00 is satisfied, which defines the shape of the third lens L3 and contributes to correcting the astigmatism and distortion of the imaging optical lens 10 within the range of the conditional formula, making it possible to set the distortion aberration |Distortion|≦5%, and reducing the possibility of vignetting occurring.

[0024] In this embodiment, when the focal length of the second lens L2 is f2 and the axial thickness of the second lens L2 is d3, the conditional formula 1.50≦f2 / d3≦4.00 is satisfied, and within the range of the conditional formula, changes in the incident angle of a large-angle light ray are buffered and smoothly propagated through the optical imaging lens group, while the refractive power strength of the second lens L2 is maintained, chromatic aberration is improved, imaging quality is improved, and the chromatic aberration |LC|≦1.0 μm is satisfied.

[0025] In this embodiment, when the radius of curvature of the object side surface of the second lens L2 is R3 and the radius of curvature of the image side surface of the second lens L2 is R4, the conditional formula 1.50≦R3 / R4≦5.00 is satisfied, which defines the shape of the second lens L2 and is advantageous in reducing the degree of deflection of light passing through the lens within the range of the conditional formula, so that the imaging optical lens 10 has good imaging quality and low sensitivity.

[0026] In this embodiment, when the focal length of the third lens L3 is f3, the conditional formula -1.20≦f3 / f≦-0.60 is satisfied, thereby defining the ratio between the focal length f3 of the third lens L3 and the focal length f of the imaging optical lens 10. By appropriately allocating the optical focal length of the imaging optical lens 10 within the range of the conditional formula, the imaging optical lens 10 has good imaging quality and low sensitivity.

[0027] In this embodiment, the first lens L1 has a positive refractive power. The object side surface of the first lens L1 is a paraxial convex surface, and the image side surface of the first lens L1 is a paraxial concave surface. In other optional embodiments, the object side surface and the image side surface of the first lens L1 may be set in other concave-convex distribution conditions, and the first lens L1 may have a negative refractive power.

[0028] In this embodiment, when the radius of curvature of the object side surface of the first lens L1 is R1 and the radius of curvature of the image side surface of the first lens L1 is R2, the conditional formula -126.25≦(R1+R2) / (R1-R2)≦-1.80 is satisfied, which defines the shape of the first lens L1, and within the range of the conditional formula, it is advantageous to reduce the degree of deflection of light passing through the lens, and the aberration can be effectively reduced, so that the imaging optical lens 10 has good imaging quality and low sensitivity. Preferably, it satisfies -78.91≦(R1+R2) / (R1-R2)≦-2.25.

[0029] In this embodiment, when the axial thickness of the first lens L1 is d1, the conditional expression 0.08≦d1 / TTL≦0.45 is satisfied, and within the range of the conditional expression, it is possible to contribute to shortening the overall length of the optical system and to achieve the effect of extremely thinning. Preferably, it satisfies 0.13≦d1 / TTL≦0.36.

[0030] In this embodiment, the second lens L2 has a positive refractive power. The object side surface of the second lens L2 is a paraxial concave surface, and the image side surface of the second lens L2 is a paraxial convex surface. In other optional embodiments, the object side surface and the image side surface of the second lens L2 may be set in other concave-convex distribution conditions, and the second lens L2 may have a negative refractive power.

[0031] In this embodiment, when the focal length of the second lens L2 is f2, the conditional formula 0.23≦f2 / f≦1.61 is satisfied, thereby defining the ratio between the focal length f2 of the second lens L2 and the focal length f of the imaging optical lens 10, and by appropriately allocating the optical focal length of the imaging optical lens 10 within the range of the conditional formula, the imaging optical lens 10 has good imaging quality and low sensitivity. Preferably, 0.36≦f2 / f≦1.29 is satisfied.

[0032] In this embodiment, when the radius of curvature of the object side surface of the second lens L2 is R3 and the radius of curvature of the image side surface of the second lens L2 is R4, the conditional formula 0.75≦(R3+R4) / (R3-R4)≦7.43 is satisfied, which defines the shape of the second lens L2 and is favorable for alleviating the degree of deflection of light passing through the lens within the range of the conditional formula, effectively reducing aberration, and the imaging optical lens 10 has good imaging quality and low sensitivity. Preferably, the conditional formula 1.20≦(R3+R4) / (R3-R4)≦5.94 is satisfied.

[0033] In this embodiment, when the axial thickness of the second lens L2 is d3, the condition 0.09≦d3 / TTL≦0.36 is satisfied, and within the range of the condition, it is possible to contribute to shortening the overall length of the optical system and to achieve the effect of extremely thinning. Preferably, it satisfies 0.14≦d3 / TTL≦0.29.

[0034] In this embodiment, the third lens L3 has negative refractive power. The object side surface of the third lens L3 is a paraxial convex surface, and the image side surface of the third lens L3 is a paraxial concave surface. In other optional embodiments, the object side surface and the image side surface of the third lens L3 may be set in other concave-convex distribution conditions, and the third lens L3 may have positive refractive power.

[0035] In this embodiment, when 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, the conditional formula 0.83≦(R5+R6) / (R5-R6)≦8.91 is satisfied, which defines the shape of the third lens L3 and is favorable for alleviating the degree of deflection of light passing through the lens within the range of the conditional formula, effectively reducing aberration, and the imaging optical lens 10 has good imaging quality and low sensitivity. Preferably, the conditional formula 1.33≦(R5+R6) / (R5-R6)≦7.13 is satisfied.

[0036] In this embodiment, when the axial thickness of the third lens L3 is d5, the conditional expression 0.02≦d5 / TTL≦0.12 is satisfied, and within the range of the conditional expression, it is possible to contribute to shortening the overall length of the optical system and to achieve the effect of extremely thinning. Preferably, 0.02≦d5 / TTL≦0.10 is satisfied.

[0037] In this embodiment, when the composite focal length of the first lens L1 and the second lens L2 is f12, the conditional formula 0.31≦f12 / f≦1.18 is satisfied, and within the range of the conditional formula, it is possible to eliminate aberration and distortion of the imaging optical lens 10, suppress the back focus of the imaging optical lens 10, and maintain the compactness of the imaging lens system. Preferably, 0.50≦f12 / f≦0.95 is satisfied.

[0038] In this embodiment, when the aperture value of the imaging optical lens 10 is FNO, the lens satisfies the condition FNO≦3.47, thereby achieving a large aperture and good imaging performance. Preferably, the lens satisfies FNO≦3.41.

[0039] When the above relationship is satisfied, the imaging optical lens 10 has good optical performance, has low sensitivity, and can realize medium to long distance imaging. Based on the characteristics of the imaging optical lens 10, the imaging optical lens 10 is particularly applied to the vehicle-mounted imaging optical lens 10 of the driver monitoring system, and the operating band is the near-infrared wavelength band.

[0040] The imaging optical lens 10 according to the present invention will be described below using examples. Symbols used in each example are as follows. The units of focal length, axial distance, radius of curvature, axial thickness, inflection point position, and stationary point position are mm.

[0041] TTL is the optical length (the axial distance from the object side surface of the first lens L1 to the image plane Si) and is expressed in mm.

[0042] In addition, at least one of the object side surface and the image side surface of each lens may be provided with an inflection point and / or a stationary point to meet the demand for high quality imaging. Specific embodiments are described below.

[0043] Tables 1 and 2 show the design data of the imaging optical lens 10 shown in FIG.

[0044] [Table 1]

[0045] The meaning of each symbol is as follows. S1: Aperture R: Radius of curvature at the center of the optical surface R1: Radius of curvature of the object side surface of the first lens L1 R2: Radius of curvature of the image side surface of the first lens L1 R3: Radius of curvature of the object side surface of the second lens L2 R4: Radius of curvature of the image side of the second lens L2 R5: Radius of curvature of the object side of the third lens L3 R6: Radius of curvature of the image side of the third lens L3 R7: Radius of curvature of the object side of the optical filter GF1 R8: Radius of curvature of the image side of the optical filter GF1 R9: Radius of curvature of the object side of the optical filter GF2 R10: Radius of curvature of the image side of the optical filter GF2 d: Axial thickness of lens, axial distance between lenses d0: The axial distance from the aperture S1 to the object side of the first lens L1 d1: Axial thickness of the first lens L1 d2: The axial distance from the image side surface of the first lens L1 to the object side surface of the second lens L2 d3: Axial thickness of the second lens L2 d4: The axial distance from the image side surface of the second lens L2 to the object side surface of the third lens L3 d5: Axial thickness of the third lens L3 d6: The axial distance from the image side surface of the third lens L3 to the object side surface of the optical filter GF1 d7: On-axis thickness of optical filter GF1 d8: The axial distance from the image side of optical filter GF1 to the object side of optical filter GF2 d9: On-axis thickness of optical filter GF2 d10: The axial distance from the image side of the optical filter GF2 to the image plane Si nd: Refractive index of d line nd1: refractive index of the first lens L1 at the d line nd2: refractive index of the d line of the second lens L2 nd3: refractive index of the d line of the third lens L3 ndg1: Refractive index of the d line of the optical filter GF1 ndg2: Refractive index of the d line of the optical filter GF2 vd: Abbe number v1: Abbe number of the first lens L1 v2: Abbe number of the second lens L2 v3: Abbe number of the third lens L3 vg1: Abbe number of optical filter GF1 vg2: Abbe number of optical filter GF2

[0046] Table 2 shows the aspheric data of each lens in the imaging optical lens 10 according to the first embodiment of the present invention.

[0047] [Table 2]

[0048] Here, k is a conic coefficient, and A4, A6, A8, A10, A12, A14, A16, A18, A20, A22, A24, A26, A28, and A30 are aspheric coefficients.

[0049] y=(x 2 / R) / [1+{1-(k+1)(x 2 R 2 )} 1 / 2 ]+A4x 4 +A6x 6 +A8x 8 +A10x 10 +A12x 12+A14x 14 +A16x 16 +A18x 18 +A20x 20 +A22x 22 +A24x 24 +A26x 26 +A28x 28 +A30x 30 (18)

[0050] Here, x is the perpendicular distance between a point on the aspheric curve and the optical axis, and y is the aspheric depth (the perpendicular distance between a point on the aspheric surface that is x away from the optical axis and a tangent plane that is tangent to the vertex of the aspheric surface on the optical axis).

[0051] For convenience, the aspheric surface of each lens surface is expressed by the above formula (18). However, the present invention is not particularly limited to the aspheric polynomial of this formula (18).

[0052] Tables 3 and 4 show the design data of the inflection points and stationary points of each lens in the imaging optical lens 10 according to this embodiment. Here, P1R1 and P1R2 respectively indicate the object side surface and the image side surface of the first lens L1, P2R1 and P2R2 respectively indicate the object side surface and the image side surface of the second lens L2, and P3R1 and P3R2 respectively indicate the object side surface and the image side surface of the third lens L3. The corresponding data in the "inflection point position" column is the vertical distance from the inflection point set on the surface of each lens to the optical axis of the imaging optical lens 10. The corresponding data in the "stationary point position" column is the vertical distance from the stationary point set on the surface of each lens to the optical axis of the imaging optical lens 10.

[0053] [Table 3]

[0054] [Table 4]

[0055] Fig. 2 is a schematic diagram showing the field curvature and distortion aberration after light with a wavelength of 940 nm passes through the imaging optical lens 10. The field curvature S in Fig. 2 is the field curvature in the sagittal direction, and T is the field curvature in the tangential direction. Figs. 3 and 4 are schematic diagrams showing the magnification chromatic aberration and axial chromatic aberration after light with wavelengths of 960 nm, 940 nm, and 920 nm, respectively, passes through the imaging optical lens 10.

[0056] As shown in Table 25, the first embodiment satisfies each of the conditional expressions.

[0057] In this embodiment, the entrance pupil diameter ENPD of the imaging optical lens 10 is 2.123 mm, the full field of view image height IH is 2.264 mm, and the diagonal angle of view FOV is 56.12°, so that the imaging optical lens 10 meets the design requirements for low sensitivity and medium to long distance imaging, its on-axis and off-axis chromatic aberrations are sufficiently corrected, and it has excellent optical properties.

[0058] (Second embodiment) FIG. 5 is a schematic diagram showing the configuration of the imaging optical lens 20 in the second embodiment. The second embodiment is basically the same as the first embodiment, and the meanings of the symbols are also the same as in the first embodiment, so repeated explanations of the same parts will be omitted here.

[0059] Tables 5 and 6 show the design data of the imaging optical lens 20 shown in FIG.

[0060] [Table 5]

[0061] Table 6 shows the aspheric data of each lens in the imaging optical lens 20 according to the second embodiment of the present invention.

[0062] [Table 6]

[0063] Tables 7 and 8 show the design data of the inflection points and stationary points of each lens in the imaging optical lens 20 according to this embodiment.

[0064] [Table 7]

[0065] [Table 8]

[0066] Fig. 6 is a schematic diagram showing the field curvature and distortion aberration after light with a wavelength of 940 nm passes through the imaging optical lens 20. The field curvature S in Fig. 6 is the field curvature in the sagittal direction, and T is the field curvature in the tangential direction. Figs. 7 and 8 are schematic diagrams showing the magnification chromatic aberration and the axial chromatic aberration after light with wavelengths of 960 nm, 940 nm, and 920 nm, respectively, passes through the imaging optical lens 20.

[0067] As shown in Table 25, the second embodiment satisfies each of the conditional expressions.

[0068] In this embodiment, the entrance pupil diameter ENPD of the imaging optical lens 20 is 2.123 mm, the full field of view image height IH is 2.264 mm, and the diagonal field angle FOV is 43.71°, so that the imaging optical lens 20 meets the design requirements for low sensitivity and medium to long distance imaging, its on-axis and off-axis chromatic aberrations are sufficiently corrected, and it has excellent optical properties.

[0069] (Third embodiment) FIG. 9 is a schematic diagram showing the configuration of the imaging optical lens 30 in the third embodiment. The third embodiment is basically the same as the first embodiment, and the meanings of the symbols are also the same as in the first embodiment, so repeated explanations of the same parts will be omitted here.

[0070] Tables 9 and 10 show the design data of the imaging optical lens 30 shown in FIG.

[0071] [Table 9]

[0072] Table 10 shows the aspheric data of each lens in the imaging optical lens 30 according to the third embodiment of the present invention.

[0073] [Table 10]

[0074] Tables 11 and 12 show the design data of the inflection points and stationary points of each lens in the imaging optical lens 30 according to this embodiment.

[0075] [Table 11]

[0076] [Table 12]

[0077] Fig. 10 is a schematic diagram showing the field curvature and distortion aberration after light with a wavelength of 940 nm passes through the imaging optical lens 30. The field curvature S in Fig. 10 is the field curvature in the sagittal direction, and T is the field curvature in the tangential direction. Figs. 11 and 12 are schematic diagrams showing the magnification chromatic aberration and the axial chromatic aberration after light with wavelengths of 960 nm, 940 nm, and 920 nm, respectively, passes through the imaging optical lens 30.

[0078] As shown in Table 25, the third embodiment satisfies each of the conditional expressions.

[0079] In this embodiment, the entrance pupil diameter ENPD of the imaging optical lens 30 is 2.123 mm, the full field of view image height IH is 2.264 mm, and the diagonal angle of view FOV is 46.29°, so that the imaging optical lens 30 meets the design requirements for low sensitivity and medium to long distance imaging, its on-axis and off-axis chromatic aberrations are sufficiently corrected, and it has excellent optical properties.

[0080] (Fourth embodiment) FIG. 13 is a schematic diagram showing the configuration of the imaging optical lens 40 in the fourth embodiment. The fourth embodiment is basically the same as the first embodiment, and the meanings of the symbols are also the same as in the first embodiment, so repeated explanations of the same parts will be omitted here.

[0081] Tables 13 and 14 show the design data of the imaging optical lens 40 shown in FIG.

[0082] [Table 13]

[0083] Table 14 shows the aspheric data of each lens in the imaging optical lens 40 according to the fourth embodiment of the present invention.

[0084] [Table 14]

[0085] Tables 15 and 16 show the design data of the inflection points and stationary points of each lens in the imaging optical lens 40 according to this embodiment.

[0086] [Table 15]

[0087] [Table 16]

[0088] Fig. 14 is a schematic diagram showing the field curvature and distortion aberration after light with a wavelength of 940 nm passes through the imaging optical lens 40. The field curvature S in Fig. 14 is the field curvature in the sagittal direction, and T is the field curvature in the tangential direction. Figs. 15 and 16 are schematic diagrams showing the magnification chromatic aberration and the axial chromatic aberration after light with wavelengths of 960 nm, 940 nm, and 920 nm, respectively, passes through the imaging optical lens 40.

[0089] As shown in Table 25, the fourth embodiment satisfies each of the conditional expressions.

[0090] In this embodiment, the entrance pupil diameter ENPD of the imaging optical lens 40 is 2.123 mm, the full field of view image height IH is 2.264 mm, and the diagonal angle of view FOV is 36.22°, so that the imaging optical lens 40 meets the design requirements for low sensitivity and medium to long distance imaging, its on-axis and off-axis chromatic aberrations are sufficiently corrected, and it has excellent optical properties.

[0091] (Fifth embodiment) FIG. 17 is a schematic diagram showing the configuration of the imaging optical lens 50 in the fifth embodiment. The fifth embodiment is basically the same as the first embodiment, and the meanings of the symbols are also the same as in the first embodiment, so repeated explanations of the same parts will be omitted here.

[0092] Tables 17 and 18 show the design data of the imaging optical lens 50 shown in FIG.

[0093] [Table 17]

[0094] Table 18 shows the aspheric data of each lens in the imaging optical lens 50 according to the fifth embodiment of the present invention.

[0095] [Table 18]

[0096] Tables 19 and 20 show the design data of the inflection points and stationary points of each lens in the imaging optical lens 50 according to this embodiment.

[0097] [Table 19]

[0098] [Table 20]

[0099] Fig. 18 is a schematic diagram showing the field curvature and distortion aberration after light with a wavelength of 940 nm passes through the imaging optical lens 50. The field curvature S in Fig. 18 is the field curvature in the sagittal direction, and T is the field curvature in the tangential direction. Figs. 19 and 20 are schematic diagrams showing the magnification chromatic aberration and axial chromatic aberration after light with wavelengths of 960 nm, 940 nm, and 920 nm, respectively, passes through the imaging optical lens 50.

[0100] As shown in Table 25, the fifth embodiment satisfies each of the conditional expressions.

[0101] In this embodiment, the entrance pupil diameter ENPD of the imaging optical lens 50 is 2.123 mm, the full field of view image height IH is 2.264 mm, and the diagonal field angle FOV is 55.08°, so that the imaging optical lens 50 meets the design requirements for low sensitivity and medium to long distance imaging, its on-axis and off-axis chromatic aberrations are sufficiently corrected, and it has excellent optical properties.

[0102] (Comparative Example) FIG. 21 is a schematic diagram showing the structure of an imaging optical lens 60 in a comparative example, and since the meanings of the symbols are the same as those in the first embodiment, repeated explanation of the same parts will be omitted here.

[0103] Tables 21 and 22 show the design data of the imaging optical lens 60 shown in FIG.

[0104] [Table 21]

[0105] Table 22 shows the aspheric data of each lens in the imaging optical lens 60 according to the comparative example of the present invention.

[0106] [Table 22]

[0107] Tables 23 and 24 show the design data of the inflection points and stationary points of each lens in the imaging optical lens 60 according to this comparative example.

[0108] [Table 23]

[0109] [Table 24]

[0110] Fig. 22 is a schematic diagram showing the field curvature and distortion aberration after light with a wavelength of 940 nm passes through the imaging optical lens 60. The field curvature S in Fig. 22 is the field curvature in the sagittal direction, and T is the field curvature in the tangential direction. Figs. 23 and 24 are schematic diagrams showing the magnification chromatic aberration and axial chromatic aberration after light with wavelengths of 960 nm, 940 nm, and 920 nm, respectively, passes through the imaging optical lens 60.

[0111] In this comparative example, the entrance pupil diameter ENPD of the imaging optical lens 60 is 2.123 mm, the full field of view image height IH is 2.264 mm, and the diagonal field of view angle FOV is 41.11°.

[0112] Table 25 shows various numerical values ​​and values ​​corresponding to parameters defined by conditional expressions in the first to fifth embodiments and the comparative example. Clearly, the imaging optical lens 60 of the comparative example does not satisfy the above conditional expression 0.80≦f1 / f≦1.60. The imaging optical lens 60 cannot effectively achieve both low sensitivity and medium-to-long distance imaging, and the optical performance is not sufficiently excellent.

[0113] [Table 25]

[0114] As will be understood by those skilled in the art, the above-described embodiments are specific embodiments for realizing the present invention, and in actual application, various changes in form and details are possible without departing from the spirit and scope of the present invention.

Claims

1. An imaging optical lens, the imaging optical lens including, in order from an object side to an image side, a first lens, a second lens, and a third lens, an optical lens that satisfies the following conditional expressions (1) to (5): f is a focal length of the imaging optical lens, f1 is a focal length of the first lens, d2 is an axial distance from the image side surface of the first lens to the object side surface of the second lens, TTL is an optical length of the imaging optical lens, FOV is an angle of view of the imaging optical lens, IH is a total field of view image height of the imaging optical lens, R5 is a radius of curvature of the object side surface of the third lens, R6 is a radius of curvature of the image side surface of the third lens, and n1 is a refractive index of the first lens. 0.80≦f1 / f≦1.60 (1) 0.14≦d2 / TTL≦0.22 (2) 100.00≦(FOV×f) / IH≦115.00 (3) 1.40≦R5 / R6≦4.00 (4) 1.70≦n1≦2.10 (5)

2. 2. The imaging optical lens according to claim 1, wherein the following conditional expression (6) is satisfied, where f2 is a focal length of the second lens and d3 is an axial thickness of the second lens: 1.50≦f2 / d3≦4.00 (6)

3. 2. The imaging optical lens according to claim 1, wherein when a radius of curvature of an object-side surface of the second lens is R3 and a radius of curvature of an image-side surface of the second lens is R4, the following conditional expression (7) is satisfied: 1.50≦R3 / R4≦5.00 (7)

4. 2. The imaging optical lens according to claim 1, wherein the following conditional expression (8) is satisfied when the focal length of the third lens is f3: −1.20≦f3 / f≦−0.60 (8)

5. the first lens has positive refractive power, an object side surface of the first lens is a convex surface in a paraxial direction, and an image side surface of the first lens is a concave surface in the paraxial direction; 2. The imaging optical lens according to claim 1, wherein when 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 axial thickness of the first lens is d1, the imaging optical lens satisfies the following conditional expressions (9) and (10): -126.25≦(R1+R2) / (R1-R2)≦-1.80 (9) 0.08≦d1 / TTL≦0.45 (10)

6. the second lens has positive refractive power, an object side surface of the second lens is a concave surface in a paraxial direction, and an image side surface of the second lens is a convex surface in the paraxial direction; 2. The imaging optical lens according to claim 1, wherein the imaging optical lens satisfies the following conditional expressions (11) to (13): 0.23≦f2 / f≦1.61 (11) 0.75≦(R3+R4) / (R3-R4)≦7.43 (12) 0.09≦d3 / TTL≦0.36 (13)

7. the third lens has negative refractive power, an object side surface of the third lens is a convex surface paraxially, an image side surface of the third lens is a concave surface paraxially, and an axial thickness of the third lens is d5, the imaging optical lens according to claim 1, satisfying the following conditional expressions (14) and (15): 0.83≦(R5+R6) / (R5-R6)≦8.91 (14) 0.02≦d5 / TTL≦0.12 (15)

8. 2. The imaging optical lens according to claim 1, wherein the following conditional expression (16) is satisfied when a composite focal length of the first lens and the second lens is f12: 0.31≦f12 / f≦1.18 (16)

9. 2. The imaging optical lens according to claim 1, wherein the following conditional expression (17) is satisfied, when the aperture value of the imaging optical lens is FNO: FNO≦3.47 (17)

10. The imaging optical lens of claim 1 , wherein the first lens is made of a glass material, and the second lens and the third lens are made of a plastic material.

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