Image capturing optical lens

Abstract

To provide an optical lens, in particular an image capturing optical lens.SOLUTION: An image capturing optical lens disclosed herein consists of a first lens having negative refractive power, a second lens having positive refractive power, a third lens having positive refractive power, and a fourth lens having negative refractive power, arranged in order from the object side to the image side, and satisfies the following conditional expressions: -30.00≤f1 / d1≤-8.00, 2.00≤TTL / f≤3.00, -2.30≤f34 / f<-1.30, 58.00≤v1≤82.00, 0.25≤d2 / TTL≤0.45, where f represents a focal length of the image capturing optical lens, f1 represents a focal length of the first lens, f34 represents a composite focal length of the third and fourth lenses, d1 represents an axial thickness of the first lens, d2 represents an axial distance from an image-side surface of the first lens to an object-side surface of the second lens, TTL represents an optical length of the image capturing optical lens, and v1 represents an Abbe number of the first lens.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to the 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 rise of various smart devices, the demand for miniaturized imaging optical lenses is increasing, and the pixel size of the photosensitive element is reduced, and the current electronic products tend to develop with good functions and a light, thin, and portable appearance, so that miniaturized imaging optical lenses with good imaging quality have become the mainstream in the current market. In order to obtain good imaging quality, a multi-lens structure is often used. In addition, with the development of technology and the increasing diversification needs of users, the pixel area of ​​the photosensitive element is shrinking, and the system's requirements for imaging quality are increasing, so that a four-lens structure gradually appears in the lens design. There is a demand for imaging optical lenses with good optical performance. Summary of the Invention [Problem to be solved by the invention]

[0003] In view of the above problems, the present invention aims to provide an imaging optical lens that has good optical performance and meets design requirements. [Means for solving the problem]

[0004] In order to solve the above technical problems, an embodiment of the present invention provides an imaging optical lens, which is composed of, in order from the object side to the image side, a first lens having negative refractive power, a second lens having positive refractive power, a third lens having positive refractive power, and a fourth lens having negative refractive power, and satisfies the following conditional formulas (1) to (5), where f is a focal length of the imaging optical lens, f1 is a focal length of the first lens, f34 is a composite focal length of the third lens and the fourth lens, d1 is an axial thickness 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, and v1 is an Abbe number of the first lens. -30.00≦f1 / d1≦-8.00 (1) 2.00≦TTL / f≦3.00 (2) -2.30≦f34 / f<-1.30 (3) 58.00≦v1≦82.00 (4) 0.25≦d2 / TTL≦0.45 (5)

[0005] Preferably, when the central radius of curvature of the object side surface of the second lens is R3 and the central radius of curvature of the image side surface of the second lens is R4, the following conditional formula (6) is satisfied. -6.00≦R3 / R4≦-1.00 (6)

[0006] Preferably, when the focal length of the fourth lens is f4 and the on-axis thickness of the fourth lens is d7, the following conditional expression (7) is satisfied. -3.00≦f4 / d7≦-1.50 (7)

[0007] Preferably, the object side surface of the first lens is a convex surface paraxially, the image side surface of the first lens is a concave surface paraxially, and when a central radius of curvature of the object side surface of the first lens is R1 and a central radius of curvature of the image side surface of the first lens is R2, the following conditional expressions (8) to (10) are satisfied. -5.50≦f1 / f≦-1.08 (8) 1.77≦(R1+R2) / (R1-R2)≦10.09 (9) 0.02≦d1 / TTL≦0.10 (10)

[0008] Preferably, the object side surface of the second lens is a convex surface paraxially, the image side surface of the second lens is a convex surface paraxially, and when the focal length of the second lens is f2, the central radius of curvature of the object side surface of the second lens is R3, the central radius of curvature of the image side surface of the second lens is R4, and the axial thickness of the second lens is d3, the following conditional expressions (11) to (13) are satisfied. 0.29≦f2 / f≦1.09 (11) 0≦(R3+R4) / (R3-R4)≦1.07 (12) 0.02≦d3 / TTL≦0.31 (13)

[0009] Preferably, the object side surface of the third lens is a concave surface paraxially, the image side surface of the third lens is a convex surface paraxially, and when a focal length of the third lens is f3, a central radius of curvature of the object side surface of the third lens is R5, a central radius of curvature of the image side surface of the third lens is R6, and an axial thickness of the third lens is d5, the following conditional expressions (14) to (16) are satisfied. 0.39≦f3 / f≦1.87 (14) 0.65≦(R5+R6) / (R5-R6)≦2.73 (15) 0.02≦d5 / TTL≦0.09 (16)

[0010] Preferably, the object side surface of the fourth lens is a paraxially concave surface, the image side surface of the fourth lens is a paraxially concave surface, and when a focal length of the fourth lens is f4, a central radius of curvature of the object side surface of the fourth lens is R7, a central radius of curvature of the image side surface of the fourth lens is R8, and an axial thickness of the fourth lens is d7, the following conditional expressions (17) to (19) are satisfied. -1.32≦f4 / f≦-0.36 (17) -1.31≦(R7+R8) / (R7-R8)≦-0.06 (18) 0.04≦d7 / TTL≦0.27 (19)

[0011] Preferably, the first lens, the second lens, the third lens and the fourth lens are made of a glass material.

[0012] Preferably, when the angle of view in a diagonal direction of the imaging optical lens is taken as FOV, the following conditional expression (20) is satisfied: FOV≧46.18° (20)

[0013] Preferably, when the image height of the imaging optical lens is IH, the following conditional expression (21) is satisfied. TTL / IH≦7.14 (21) Effect of the Invention

[0014] The imaging optical lens according to the present invention has excellent optical characteristics and good optical performance, and can be applied to imaging lens units of mobile phones, in-vehicle lenses, and web imaging lenses, particularly those constituted by imaging elements such as high-pixel CCDs and CMOSs.

[0015] 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. [Brief description of the drawings]

[0016] [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 longitudinal chromatic aberration 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 the field curvature and distortion of the imaging optical lens shown in FIG. [Diagram 5] FIG. 11 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 longitudinal chromatic aberration 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 field curvature and distortion 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] 10 is a schematic diagram showing the longitudinal chromatic aberration 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] 10A and 10B are schematic diagrams showing the field curvature and distortion of the imaging optical lens shown in FIG. [Figure 13] FIG. 13 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 longitudinal chromatic aberration 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 field curvature and distortion 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] 18 is a schematic diagram showing the longitudinal chromatic aberration 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] 18A to 18C are schematic diagrams showing the field curvature and distortion of the imaging optical lens shown in FIG. 17. [Figure 21] FIG. 13 is a schematic diagram showing the configuration of an imaging optical lens according to a comparative embodiment of the present invention. [Figure 22] 22 is a schematic diagram showing the longitudinal chromatic aberration 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] 22A to 22C are schematic diagrams showing the field curvature and distortion 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) Referring to the drawings, the present invention provides an imaging optical lens 10. As shown in Fig. 1, the imaging optical lens 10 according to the first embodiment of the present invention is composed of a total of four lenses. Specifically, the imaging optical lens 10 includes, in order from the object side to the image side, a first lens L1, a diaphragm S1, a second lens L2, a third lens L3, and a fourth lens L4. An optical element such as an optical filter GF may be provided between the fourth lens L4 and an image plane Si.

[0019] In this embodiment, the first lens L1, the second lens L2, the third lens L3, and the fourth lens L4 are all made of glass, and the optical performance of the imaging optical lens can be improved by appropriately selecting the glass lens. In other optional embodiments, each lens may be made of other materials.

[0020] When the focal length of the first lens L1 is f1 and the axial thickness of the first lens L1 is d1, the following relationship is satisfied: -30.00≦f1 / d1≦-8.00. When f1 / d1 satisfies the above condition, it is advantageous to mitigate the change in the incident angle of the light beam, and the light beam is smoothly propagated through the imaging optical lens 10, while maintaining the refractive power strength of the first lens L1, improving chromatic aberration, and improving the imaging quality, and |LC|≦5.0 μm.

[0021] When the focal length of the imaging optical lens 10 is f and the optical length of the imaging optical lens 10 is TTL, 2.00≦TTL / f≦3.00 is satisfied, thereby defining the ratio between the optical length TTL and the focal length f of the imaging optical lens 10. Within the range defined by the conditional formula, the length of the imaging optical lens 10 can be effectively controlled.

[0022] When the composite focal length of the third lens L3 and the fourth lens L4 is f34, -2.30≦f34 / f<-1.30 is satisfied, thereby defining the ratio of the composite focal length f34 of the third lens L3 and the fourth lens L4 to the focal length of the imaging optical lens 10. Within the range defined by the conditional formula, it is possible to control the force of light rays after the second lens L2, reduce aberrations caused by wide-angle light rays, and make the lens structure more compact.

[0023] When the Abbe number of the first lens L1 is v1, the condition 58.00≦v1≦82.00 is satisfied, thereby defining the Abbe number of the first lens L1. Within the range defined by the conditional formula, the material attributes can be effectively allocated to improve aberrations and improve imaging quality.

[0024] 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, the following is satisfied: 0.25≦d2 / TTL≦0.45. Within the range defined by this conditional formula, the distance between the two lenses at the aperture is large, and stable transition of light rays near the aperture within a certain optical length can be ensured, which is advantageous for improving image quality.

[0025] When the central radius of curvature of the object side surface of the second lens L2 is R3 and the central radius of curvature of the image side surface of the second lens L2 is R4, the following is satisfied: -6.00≦R3 / R4≦-1.00. Within the range defined by the conditional formula, it is advantageous to reduce the degree of deflection of light passing through the lens, and the amount of field curvature of the imaging optical lens 10 can be effectively balanced, and the deviation of the field curvature in the central field of view can be reduced to less than 0.025 mm.

[0026] When the focal length of the fourth lens L4 is f4 and the on-axis thickness of the fourth lens L4 is d7, the following is satisfied: -3.00≦f4 / d7≦-1.50. Within the range defined by the conditional expression, the fourth lens L4 contributes to maintaining a negative refractive power of sufficient strength to correct off-axis aberrations at the image side edge, and the thickness of the fourth lens L4 can be effectively controlled to keep costs down.

[0027] In this embodiment, the object side surface of the first lens L1 is a paraxially convex surface, and the image side surface is a paraxially concave surface, and the first lens L1 has a negative refractive power. In other optional embodiments, the object side surface and the image side surface of the first lens L1 may be arranged in other concave-convex distribution situations.

[0028] The imaging optical lens 10 further satisfies -5.50≦f1 / f≦-1.08, thereby defining the ratio between the focal length f1 of the first lens L1 and the focal length of the imaging optical lens 10. Within this range, it is advantageous to realize an ultra-wide angle. Preferably, it satisfies -3.44≦f1 / f≦-1.34.

[0029] 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 L2 is R2, the following condition is satisfied: 1.77≦(R1+R2) / (R1-R2)≦10.09. This defines the shape of the first lens L1. Within this range, it is advantageous for realizing a super wide angle. Preferably, the following condition is satisfied: 2.83≦(R1+R2) / (R1-R2)≦8.07.

[0030] The imaging optical lens 10 further satisfies 0.02≦d1 / TTL≦0.10. Within the range defined by the conditional expression, it is advantageous for miniaturization. Preferably, it satisfies 0.03≦d1 / TTL≦0.08.

[0031] In this embodiment, the object side surface of the second lens L2 is a paraxially convex surface, and the image side surface of the second lens L2 is a paraxially convex surface, and the second lens L2 has a positive refractive power. In other optional embodiments, the object side surface and the image side surface of the second lens L2 may be arranged in other concave-convex distribution situations.

[0032] In this embodiment, when the focal length of the second lens L2 is f2, 0.29≦f2 / f≦1.09 is satisfied, and this defines the ratio between the focal length f2 of the second lens L2 and the focal length of the imaging optical lens 10. Within this range, the amount of field curvature of the system can be effectively balanced. Preferably, 0.47≦f2 / f≦0.88 is satisfied.

[0033] The imaging optical lens 10 further satisfies 0≦(R3+R4) / (R3-R4)≦1.07, which defines the shape of the second lens L2. Within this range, it is advantageous to realize a super wide angle. Preferably, it satisfies 0≦(R3+R4) / (R3-R4)≦0.86.

[0034] When the axial thickness of the second lens L2 is d3, the condition 0.02≦d3 / TTL≦0.31 is satisfied. Within the range defined by the condition, it is advantageous for size reduction. Preferably, the condition 0.03≦d3 / TTL≦0.25 is satisfied.

[0035] The third lens L3 has a paraxially concave object side surface and a paraxially convex image side surface, and the third lens L3 has a positive refractive power. In other optional embodiments, the object side surface and the image side surface of the third lens L3 may be arranged in other concave-convex distribution situations.

[0036] When the focal length of the third lens L3 is f3, the following relationship is satisfied: 0.39≦f3 / f≦1.87. Due to the reasonable distribution of the refractive power, the system has excellent imaging quality and low sensitivity. Preferably, the following relationship is satisfied: 0.63≦f3 / f≦1.50.

[0037] 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, 0.65≦(R5+R6) / (R5-R6)≦2.73 is satisfied, and the shape of the third lens L3 is defined accordingly. Within this range, the degree of deflection of light rays can be reduced to effectively correct chromatic aberration. Preferably, 1.03≦(R5+R6) / (R5-R6)≦2.18 is satisfied.

[0038] When the axial thickness of the third lens L3 is d5, the following relationship is satisfied: 0.02≦d5 / TTL≦0.09. Within the range defined by the conditional expression, this is advantageous for size reduction. Preferably, the following relationship is satisfied: 0.03≦d5 / TTL≦0.08.

[0039] In this embodiment, the fourth lens L4 has a paraxially concave object side surface and a paraxially concave image side surface, and the fourth lens L4 has a negative refractive power. In other optional embodiments, the object side surface and the image side surface of the fourth lens L4 may be arranged in other concave-convex distribution situations.

[0040] When the focal length of the fourth lens L4 is f4, the following relationship is satisfied: -1.32≦f4 / f≦-0.36. Due to the reasonable distribution of the refractive power, the system has excellent imaging quality and low sensitivity. Preferably, the following relationship is satisfied: -0.83≦f4 / f≦-0.45.

[0041] When the axial thickness of the fourth lens L4 is d7, the condition 0.04≦d7 / TTL≦0.27 is satisfied. Within the range defined by the conditional expression, it is advantageous for size reduction. Preferably, the condition 0.07≦d7 / TTL≦0.21 is satisfied.

[0042] In this embodiment, when the angle of view in the diagonal direction of the imaging optical lens 10 is taken as FOV, FOV≧46.18° is satisfied. This is advantageous for realizing a wide angle. Preferably, FOV≧46.65° is satisfied.

[0043] In this embodiment, when the image height of the imaging optical lens 10 is IH, TTL / IH≦7.14 is satisfied. This is advantageous for miniaturization. Preferably, TTL / IH≦6.94 is satisfied.

[0044] In this embodiment, the aperture value FNO of the imaging optical lens 10 is 16.43 or less, which allows for a large aperture and excellent imaging performance of the imaging optical lens. Preferably, the aperture value FNO of the imaging optical lens 10 is 16.11 or less.

[0045] The imaging optical lens 10 has good optical performance, and depending on the characteristics of the imaging optical lens 10, the imaging optical lens 10 can be applied to an in-vehicle lens, an imaging lens unit of a mobile phone, and a WEB imaging lens, in particular, configured with an imaging element such as a high-pixel CCD or CMOS.

[0046] The imaging optical lens 10 of the present invention will be described below using examples. The symbols used in each example are as follows. The focal length, axial distance, central radius of curvature, axial thickness, inflection point position, and stationary point position are all in mm.

[0047] 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. Aperture value FNO refers to the ratio of the effective focal length of an imaging optical lens to the entrance pupil diameter.

[0048] Preferably, inflection points and / or stationary points may be further set on the object side and / or image side of the lens to meet the demand for high quality imaging, and specific embodiments are given below.

[0049] Tables 1 and 2 show design data for the imaging optical lens 10 according to the first embodiment of the present invention.

[0050] [Table 1]

[0051] Here, the meanings of the symbols are as follows: S1: Aperture R: Radius of curvature at the center of the optical surface R1: The central radius of curvature of the object side of the first lens L1 R2: Radius of curvature of the center of the image side of the first lens L1 R3: The central radius of curvature of the object side of the second lens L2 R4: Radius of curvature of the center of the image side of the second lens L2 R5: The central radius of curvature of the object side of the third lens L3 R6: The central radius of curvature of the image side of the third lens L3 R7: The central radius of curvature of the object side of the fourth lens L4 R8: The central radius of curvature of the image side of the fourth lens L4 R9: The central curvature radius of the object side of the optical filter GF R10: Central curvature radius of the image side of the optical filter GF d: Axial thickness of lens, axial distance between lenses d0: The axial distance from the aperture stop 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 fourth lens L4 d7: Axial thickness of the fourth lens L4 d8: The axial distance from the image side surface of the fourth lens L4 to the object side surface of the optical filter GF d9: Axial thickness of the optical filter GF d10: the axial distance from the image side of the optical filter GF to the image plane Si nd: Refractive index of d line (d line is green light with a wavelength of 550 nm) 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 nd4: Refractive index of the d line of the fourth lens L4 ndg: Refractive index of the d line of the optical filter GF 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 v4: Abbe number of the fourth lens L4 vg: Abbe number of the optical filter GF

[0052] Table 2 shows the aspheric data of each lens in the imaging optical lens 10 of the first embodiment according to the present invention.

[0053] [Table 2]

[0054] For convenience, the aspheric surface of each lens surface is expressed by the following formula (22): However, the present invention is not particularly limited to the aspheric polynomial of formula (22).

[0055] z=(cr 2 ) / {1+[1-(k+1)(c 2 r 2 )] 1 / 2}+A4r 4 +A6r 6 +A8r 8 +A10r 10 +A12r 12 +A14r 14 +A16r 16 (twenty two)

[0056] where k is a conic coefficient, A4, A6, A8, A10, A12, and A14 are aspheric coefficients, c is the curvature at the center of the optical surface, r is the perpendicular distance between a point on the aspheric curve and the optical axis, and z is the aspheric depth (the perpendicular distance between a point on the aspheric surface that is a distance r away from the optical axis and a tangent plane that is tangent to the vertex of the aspheric surface on the optical axis).

[0057] The corresponding data in the “Stay Point Position” column is the perpendicular distance from the stay point located on the surface of each lens to the optical axis of the imaging optical lens 10 .

[0058] Fig. 2 and Fig. 3 are schematic diagrams showing the axial chromatic aberration and lateral chromatic aberration of light having wavelengths of 650 nm, 610 nm, 555 nm, 510 nm, 470 nm, and 435 nm after passing through the imaging optical lens 10 according to the first embodiment. Fig. 4 is a schematic diagram showing the field curvature and distortion aberration of light having a wavelength of 555 nm 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.

[0059] Table 16 below shows values ​​corresponding to the parameters defined by various numerical values ​​and conditional expressions in each embodiment.

[0060] As shown in Table 16, the first embodiment satisfies each of the conditional expressions.

[0061] In this embodiment, the entrance pupil diameter ENPD of the imaging optical lens 10 is 2.194 mm, the full field of view image height IH is 10.29 mm, and the diagonal field angle FOV is 56.17°. The imaging optical lens 10 has good optical performance, and its on-axis and off-axis chromatic aberrations are sufficiently corrected, resulting in excellent optical characteristics.

[0062] Second embodiment The second embodiment is basically the same as the first embodiment, and the symbols have the same meanings as in the first embodiment, so only the differences will be described below.

[0063] Shown in FIG. 5 is an imaging optical lens 20 according to a second embodiment of the present invention.

[0064] Tables 3 and 4 show design data for the imaging optical lens 20 according to the second embodiment of the present invention.

[0065] [Table 3]

[0066] Table 4 shows the aspheric data of each lens in the imaging optical lens 20 according to the second embodiment of the present invention.

[0067] [Table 4]

[0068] Table 5 shows design data of the inflection points of each lens in the imaging optical lens 20 according to the second embodiment of the present invention. Here, 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, and P4R1 and P4R2 represent the object side surface and the image side surface of the fourth lens L4. The corresponding data in the "Inflection Point Position" column is the vertical distance from the inflection point located on the surface of each lens to the optical axis of the imaging optical lens 10.

[0069] [Table 5]

[0070] Fig. 6 and Fig. 7 are schematic diagrams showing the axial chromatic aberration and the chromatic aberration of magnification after light having wavelengths of 650 nm, 610 nm, 555 nm, 510 nm, 470 nm, and 435 nm passes through the imaging optical lens 20 according to the second embodiment. Fig. 8 is a schematic diagram showing the field curvature and the distortion aberration after light having wavelength of 555 nm passes through the imaging optical lens 20 according to the second embodiment. The field curvature S in Fig. 8 is the field curvature in the sagittal direction, and T is the field curvature in the tangential direction.

[0071] As shown in Table 16, the second embodiment satisfies each of the conditional expressions.

[0072] In this embodiment, the entrance pupil diameter ENPD of the imaging optical lens 20 is 2.493 mm, the full field of view image height IH is 5.145 mm, and the diagonal field angle FOV is 47.12°. The imaging optical lens 20 has good optical performance, and its on-axis and off-axis chromatic aberrations are sufficiently corrected, resulting in excellent optical characteristics.

[0073] Third embodiment The third embodiment is basically the same as the first embodiment, and the symbols have the same meanings as in the first embodiment, so only the differences will be described below.

[0074] Shown in FIG. 9 is an imaging optical lens 30 according to a third embodiment of the present invention.

[0075] Tables 6 and 7 show design data for the imaging optical lens 30 according to the third embodiment of the present invention.

[0076] [Table 6]

[0077] Table 7 shows the aspheric data of each lens in the imaging optical lens 30 according to the third embodiment of the present invention.

[0078] [Table 7]

[0079] Fig. 10 and Fig. 11 are schematic diagrams showing the axial chromatic aberration and the chromatic aberration of magnification after light of wavelengths 650 nm, 610 nm, 555 nm, 510 nm, 470 nm, and 435 nm passes through the imaging optical lens 30 according to the third embodiment. Fig. 12 is a schematic diagram showing the field curvature and the distortion aberration after light of wavelength 555 nm passes through the imaging optical lens 30 according to the third embodiment. The field curvature S in Fig. 12 is the field curvature in the sagittal direction, and T is the field curvature in the tangential direction.

[0080] Table 16 below shows the numerical values ​​corresponding to each conditional expression in this embodiment according to the above conditional expressions. Obviously, the imaging optical lens 30 of this embodiment satisfies the above conditional expressions.

[0081] In this embodiment, the entrance pupil diameter ENPD of the imaging optical lens 30 is 0.739 mm, the full field of view image height IH is 5.145 mm, and the diagonal field angle FOV is 110.33°. The imaging optical lens 30 has good optical performance, and its on-axis and off-axis chromatic aberrations are sufficiently corrected, resulting in excellent optical characteristics.

[0082] (Fourth embodiment) The fourth embodiment is basically the same as the first embodiment, and the symbols have the same meanings as in the first embodiment, so only the differences will be described below.

[0083] Shown in FIG. 13 is an imaging optical lens 40 according to a fourth embodiment of the present invention.

[0084] Tables 8 and 9 show design data for the imaging optical lens 40 according to the fourth embodiment of the present invention.

[0085] [Table 8]

[0086] Table 9 shows the aspheric data of each lens in the imaging optical lens 40 according to the fourth embodiment of the present invention.

[0087] [Table 9]

[0088] Table 10 shows design data for the inflection points of each lens in the imaging optical lens 40 according to the fourth embodiment of the present invention.

[0089] [Table 10]

[0090] Fig. 14 and Fig. 15 are schematic diagrams showing the axial chromatic aberration and the chromatic aberration of magnification after light of wavelengths 650 nm, 610 nm, 555 nm, 510 nm, 470 nm, and 435 nm has passed through the imaging optical lens 40 according to the fourth embodiment. Fig. 16 is a schematic diagram showing the field curvature and the distortion aberration after light of wavelength 555 nm has passed through the imaging optical lens 40 according to the fourth embodiment. The field curvature S in Fig. 16 is the field curvature in the sagittal direction, and T is the field curvature in the tangential direction.

[0091] Table 16 below shows the numerical values ​​corresponding to each conditional expression in this embodiment according to the above conditional expressions. Obviously, the imaging optical lens 40 of this embodiment satisfies the above conditional expressions.

[0092] In this embodiment, the entrance pupil diameter ENPD of the imaging optical lens 40 is 2.150 mm, the full field of view image height IH is 5.145 mm, and the diagonal field angle FOV is 52.01°. The imaging optical lens 40 has good optical performance, and its on-axis and off-axis chromatic aberrations are sufficiently corrected, resulting in excellent optical characteristics.

[0093] Fifth embodiment The fifth embodiment is basically the same as the first embodiment, and the symbols have the same meanings as in the first embodiment, so only the differences will be described below.

[0094] Shown in FIG. 17 is an imaging optical lens 50 according to a fifth embodiment of the present invention.

[0095] Tables 11 and 12 show design data for the imaging optical lens 50 according to the fifth embodiment of the present invention.

[0096] [Table 11]

[0097] Table 12 shows the aspheric data of each lens in the imaging optical lens 50 according to the fifth embodiment of the present invention.

[0098] [Table 12]

[0099] Table 13 shows the design data of the inflection points and stationary points of each lens in the imaging optical lens 50 according to the fifth embodiment of the present invention.

[0100] [Table 13]

[0101] Fig. 18 and Fig. 19 are schematic diagrams showing the axial chromatic aberration and the chromatic aberration of magnification after light of wavelengths 650 nm, 610 nm, 555 nm, 510 nm, 470 nm, and 435 nm has passed through the imaging optical lens 50 according to the fifth embodiment. Fig. 20 is a schematic diagram showing the field curvature and the distortion aberration after light of wavelength 555 nm has passed through the imaging optical lens 50 according to the fifth embodiment. The field curvature S in Fig. 20 is the field curvature in the sagittal direction, and T is the field curvature in the tangential direction.

[0102] Table 16 below shows the numerical values ​​corresponding to each conditional expression in this embodiment according to the above conditional expressions. Obviously, the imaging optical lens 50 of this embodiment satisfies the above conditional expressions.

[0103] In this embodiment, the entrance pupil diameter ENPD of the imaging optical lens 50 is 2.037 mm, the full field of view image height IH is 5.145 mm, and the diagonal field angle FOV is 57.72°. The imaging optical lens 50 has good optical performance, and its on-axis and off-axis chromatic aberrations are sufficiently corrected, resulting in excellent optical characteristics.

[0104] (Comparative embodiment) The comparative embodiment is basically the same as the first embodiment, and the symbols have the same meanings as in the first embodiment. Only the differences are listed below.

[0105] FIG. 21 shows an imaging optical lens 60 of a comparative embodiment.

[0106] Tables 14 and 15 show design data for the imaging optical lens 60 according to the comparative embodiment.

[0107] [Table 14]

[0108] Table 22 shows the aspheric data of each lens in the imaging optical lens 60 according to the comparative embodiment.

[0109] [Table 15]

[0110] Fig. 22 and Fig. 23 are schematic diagrams showing the axial chromatic aberration and the chromatic aberration of magnification after light having wavelengths of 650 nm, 610 nm, 555 nm, 510 nm, 470 nm, and 435 nm passes through the imaging optical lens 60 of the comparative embodiment. Fig. 24 is a schematic diagram showing the field curvature and the distortion aberration after light having wavelength of 555 nm passes through the imaging optical lens 60 of the comparative embodiment. The field curvature S in Fig. 24 is the field curvature in the sagittal direction, and T is the field curvature in the tangential direction.

[0111] Table 16 below shows the numerical values ​​corresponding to each conditional expression in this embodiment according to the above conditional expressions. Obviously, the imaging optical lens 60 of this embodiment satisfies the above conditional expressions.

[0112] In this embodiment, the imaging optical lens 60 has an entrance pupil diameter ENPD of 0.739 mm, a full field image height IH of 5.145 mm, and a diagonal field angle FOV of 110.33°.

[0113] The following Table 16 shows the numerical values ​​corresponding to each conditional expression in the comparative embodiment according to the above conditional expressions. Apparently, the imaging optical lens 60 of the comparative embodiment does not satisfy the above conditional expression -30.00≦f1 / d1≦-8.00, and cannot improve the chromatic aberration.

[0114] [Table 16]

[0115] 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. 1. An imaging optical lens, comprising: the imaging optical lens is composed of, in order from the object side to the image side, a first lens having negative refractive power, a second lens having positive refractive power, a third lens having positive refractive power, and a fourth lens having negative refractive power; an imaging optical lens which 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, f34 is a composite focal length of the third lens and the fourth lens, d1 is an axial thickness of the first lens, d2 is an axial distance from an image side surface of the first lens to an object side surface of the second lens, TTL is an optical length of the imaging optical lens, and v1 is an Abbe number of the first lens. −30.00≦f1 / d1≦−8.00 (1) 2.00≦TTL / f≦3.00 (2) -2.30≦f34 / f<-1.30 (3) 58.00≦v1≦82.00 (4) 0.25≦d2 / TTL≦0.45 (5)

2. 2. The imaging optical lens according to claim 1, wherein when a central radius of curvature of an object-side surface of the second lens is R3 and a central radius of curvature of an image-side surface of the second lens is R4, the following conditional expression (6) is satisfied: −6.00≦R3 / R4≦−1.00 (6)

3. 2. The imaging optical lens according to claim 1, wherein the following conditional expression (7) is satisfied, where f4 is a focal length of the fourth lens and d7 is an axial thickness of the fourth lens: −3.00≦f4 / d7≦−1.50 (7)

4. an object side surface of the first lens is a paraxially convex surface, and an image side surface of the first lens is a paraxially concave surface, 2. The imaging optical lens according to claim 1, wherein when a central radius of curvature of an object-side surface of the first lens is R1 and a central radius of curvature of an image-side surface of the first lens is R2, the imaging optical lens satisfies the following conditional expressions (8) to (10): −5.50≦f1 / f≦−1.08 (8) 1.77≦(R1+R2) / (R1-R2)≦10.09 (9) 0.02≦d1 / TTL≦0.10 (10)

5. an object side surface of the second lens is a paraxially convex surface, and an image side surface of the second lens is a paraxially convex surface, 2. The imaging optical lens according to claim 1, wherein the imaging optical lens satisfies the following conditional expressions (11) to (13): 0.29≦f2 / f≦1.09 (11) 0≦(R3+R4) / (R3-R4)≦1.07 (12) 0.02≦d3 / TTL≦0.31 (13)

6. an object side surface of the third lens is a paraxially concave surface, and an image side surface of the third lens is a paraxially convex surface, 2. The imaging optical lens according to claim 1, wherein when a focal length of the third lens is f3, a central radius of curvature of an object-side surface of the third lens is R5, a central radius of curvature of an image-side surface of the third lens is R6, and an axial thickness of the third lens is d5, the imaging optical lens satisfies the following conditional expressions (14) to (16): 0.39≦f3 / f≦1.87 (14) 0.65≦(R5+R6) / (R5-R6)≦2.73 (15) 0.02≦d5 / TTL≦0.09 (16)

7. an object side surface of the fourth lens is a paraxially concave surface, and an image side surface of the fourth lens is a paraxially concave surface, 2. The imaging optical lens according to claim 1, wherein when a focal length of the fourth lens is f4, a central radius of curvature of an object-side surface of the fourth lens is R7, a central radius of curvature of an image-side surface of the fourth lens is R8, and an axial thickness of the fourth lens is d7, the imaging optical lens satisfies the following conditional expressions (17) to (19): −1.32≦f4 / f≦−0.36 (17) -1.31≦(R7+R8) / (R7-R8)≦-0.06 (18) 0.04≦d7 / TTL≦0.27 (19)

8. The imaging optical lens according to claim 1 , wherein the first lens, the second lens, the third lens and the fourth lens are made of a glass material.

9. 9. The imaging optical lens according to claim 8, wherein the following conditional expression (20) is satisfied, where FOV is a diagonal angle of view of the imaging optical lens: FOV≧46.18° (20)

10. 2. The imaging optical lens according to claim 1, wherein the following conditional expression (21) is satisfied, where IH is an image height of the imaging optical lens: TTL / IH≦7.14 (21)

Images