Imaging optical lens

Abstract

To provide an imaging optical lens related to the field of an optical lens.SOLUTION: An imaging optical lens includes six lenses in total. The six lenses include a first lens having negative refractive power, a second lens having negative refractive power, a third lens having positive refractive power, a fourth lens having positive refractive power, a fifth lens having negative refractive power and a sixth lens having positive refractive power in this order toward an image side from an object side. Therein: the fourth lens is a prism; and when a focal distance of the second lens is f2, a focal distance of the third lens is f3, a field angle of the imaging optical lens is FOV, a focal distance of the imaging optical lens is f and an image height of the imaging optical lens in all visual field is IH, a relational expression of 4.00≤f2 / f3≤-1.20 and 95.00≤(FOV×f) / IH≤101.632 is satisfied.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] In recent years, with the emergence of various smart devices, the need for miniaturized imaging optical lenses has been increasing. As the pixel size of photosensitive elements has been shrinking, and modern electronic products are increasingly demanding superior functionality and lightweight, slim, and portable appearances, miniaturized imaging optical lenses with good imaging quality have become mainstream in the current market. To achieve excellent imaging quality, lenses often use multiple lens structures. Furthermore, with technological advances and increasingly diverse user needs, the pixel area of photosensitive elements has been shrinking, and the demand for system imaging quality has been increasing. As a result, six-lens structures have gradually emerged in lens designs. Therefore, there is a growing demand for wide-angle imaging lenses with excellent optical properties, small volume, and sufficient aberration correction. Summary of the Invention [Problem to be solved by the invention]

[0003] The present invention has been made in consideration of the above problems, and has an object to provide an imaging optical lens that has good optical performance and can satisfy the design requirements of a large aperture, an extremely thin lens, and a wide angle lens. [Means for solving the problem]

[0004] In order to achieve the above object, a technical solution of the present invention provides an imaging optical lens, which includes a total of six lenses, which are, from the object side to the image side, in order: a first lens having negative refractive power, a second lens having negative refractive power, a third lens having positive refractive power, a fourth lens having positive refractive power, a fifth lens having negative refractive power, and a sixth lens having positive refractive power, wherein the fourth lens is a prism, and the following relational expression is satisfied when the focal length of the second lens is f2, the focal length of the third lens is f3, the angle of view of the imaging optical lens is FOV, the focal length of the imaging optical lens is f, and the image height of the entire field of view of the imaging optical lens is IH: -4.00≦f2 / f3≦-1.20 95.00≦(FOV×f) / IH≦101.632

[0005] Preferably, when the focal length of the first lens is set to f1, the following relational expression is satisfied: -2.50≦f1 / f≦-1.50

[0006] Preferably, when the Abbe number of the second lens is v2 and the Abbe number of the third lens is v3, the following relational expression is satisfied. v3-v2≧30.00

[0007] Preferably, when the central radius of curvature of the object-side surface of the fifth lens is R9 and the central radius of curvature of the image-side surface of the fifth lens is R10, the following relational expression is satisfied. 2.00≦R9 / R10≦5.00

[0008] Preferably, when the focal length of the sixth lens is f6 and the axial thickness of the sixth lens is d11, the following relational expression is satisfied. 20.00≦f6 / d11≦60.00

[0009] Preferably, when the half aperture of the object-side surface of the first lens is set to SD11, the following relational expression is satisfied: SD11 / IH≦0.31

[0010] Preferably, the image-side surface of the first lens is formed as a concave surface paraxially, and satisfies the following relational expression when the central radius of curvature of the object-side surface of the first lens is R1, the central radius of curvature of the image-side surface of the first lens is R2, the axial thickness of the first lens is d1, and the total optical length of the imaging optical lens is TTL: 0.49≦(R1+R2) / (R1-R2)≦1.59 0.01≦d1 / TTL≦0.05

[0011] Preferably, the second lens has an object-side surface formed as a convex surface paraxially, an image-side surface formed as a concave surface paraxially, and satisfies the following relational expression when 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, the axial thickness of the second lens is d3, and the total optical length of the imaging optical lens is TTL: -7.55≦f2 / f≦-0.87 1.30≦(R3+R4) / (R3-R4)≦6.59 0.06≦d3 / TTL≦0.24

[0012] Preferably, the object-side surface of the third lens is formed as a convex surface paraxially, and the image-side surface is formed as a concave surface paraxially, and when 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, an axial thickness of the third lens is d5, and a total optical length of the imaging optical lens is TTL, the following relational expression is satisfied: 0.48≦f3 / f≦1.63 -3.38≦(R5+R6) / (R5-R6)≦-0.93 0.04≦d5 / TTL≦0.14

[0013] Preferably, the fourth lens has an object-side surface formed as a convex surface paraxially, an image-side surface formed as a convex surface paraxially, and satisfies the following relational expression when the focal length of the fourth lens is f4, the central radius of curvature of the object-side surface of the fourth lens is R7, the central radius of curvature of the image-side surface of the fourth lens is R8, the axial thickness of the fourth lens is d7, and the total optical length of the imaging optical lens is TTL: 0.38≦f4 / f≦1.38 0.50≦(R7+R8) / (R7-R8)≦1.50 0.18≦d7 / TTL≦0.61 [Effects of the Invention]

[0014] The beneficial effects of the present invention are as follows: The imaging optical lens of the present invention has excellent optical performance, as well as the characteristics of a large aperture, an extremely thin structure, a wide angle, and a small head, and is particularly applicable to imaging lens components for mobile phones and web imaging lenses that are configured with imaging elements such as high-pixel CCDs and CMOSs. [Brief explanation of the drawings]

[0015] To more clearly describe the technical ideas in the embodiments of the present invention, the following briefly describes the drawings necessary for describing the embodiments. Obviously, the following description of the drawings is only for describing some embodiments of the present invention, and those skilled in the art can obtain other drawings from these drawings without any creative efforts. [Figure 1] FIG. 1 is a diagram showing the structure of an imaging optical lens according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a diagram showing the spherical aberration of the imaging optical lens shown in FIG. [Figure 3] FIG. 3 is a diagram showing chromatic aberration of magnification of the imaging optical lens shown in FIG. [Figure 4] FIG. 4 is a diagram showing the field curvature and distortion of the imaging optical lens shown in FIG. [Figure 5] FIG. 5 is a diagram showing the structure of an imaging optical lens according to a second embodiment of the present invention. [Figure 6]FIG. 6 is a diagram showing the spherical aberration of the imaging optical lens shown in FIG. [Figure 7] FIG. 7 is a diagram showing chromatic aberration of magnification of the imaging optical lens shown in FIG. [Figure 8] FIG. 8 is a diagram showing the field curvature and distortion of the imaging optical lens shown in FIG. [Figure 9] FIG. 9 is a diagram showing the structure of an imaging optical lens according to a third embodiment of the present invention. [Figure 10] FIG. 10 is a diagram showing the spherical aberration of the imaging optical lens shown in FIG. [Figure 11] FIG. 11 is a diagram showing chromatic aberration of magnification of the imaging optical lens shown in FIG. [Figure 12] FIG. 12 is a diagram showing the field curvature and distortion of the imaging optical lens shown in FIG. [Figure 13] FIG. 13 is a diagram showing the structure of an imaging optical lens according to a fourth embodiment of the present invention. [Figure 14] FIG. 14 is a diagram showing the spherical aberration of the imaging optical lens shown in FIG. [Figure 15] FIG. 15 is a diagram showing chromatic aberration of magnification of the imaging optical lens shown in FIG. [Figure 16] FIG. 16 is a diagram showing the field curvature and distortion of the imaging optical lens shown in FIG. [Figure 17] FIG. 17 is a diagram showing the structure of an imaging optical lens according to a fifth embodiment of the present invention. [Figure 18] FIG. 18 is a diagram showing the spherical aberration of the imaging optical lens shown in FIG. [Figure 19] FIG. 19 is a diagram showing chromatic aberration of magnification of the imaging optical lens shown in FIG. [Figure 20] FIG. 20 is a diagram showing the field curvature and distortion of the imaging optical lens shown in FIG. [Figure 21] FIG. 21 is a diagram showing the structure of an imaging optical lens according to a comparative embodiment of the present invention. [Figure 22] FIG. 22 is a diagram showing the spherical aberration of the imaging optical lens shown in FIG. [Figure 23] FIG. 23 is a diagram showing chromatic aberration of magnification of the imaging optical lens shown in FIG. [Figure 24] FIG. 24 is a diagram showing the field curvature and distortion of the imaging optical lens shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0016] In order to clarify the objectives, technical ideas, and advantages of the present invention, the following detailed description of each embodiment of the present invention will be given with reference to the drawings. Although many technical details are described in each embodiment of the present invention to facilitate understanding of the present invention, it is obvious to those skilled in the art that the technical ideas protected by the present invention can be realized without these technical details and various changes and modifications based on the following embodiments.

[0017] Referring to Figures 1 to 20, the present invention provides imaging optical lenses 10, 20, 30, 40, and 50. Figures 1, 5, 9, 13, and 17 show imaging optical lenses 10, 20, 30, 40, and 50 of the present invention, which each include a total of six lenses. Specifically, the imaging optical lenses include, in order from the object side to the image side, a diaphragm S1, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, and a sixth lens L6. An optical element such as an optical filter GF may be provided between the sixth lens L6 and the image plane Si.

[0018] The first lens L1 is made of plastic, the second lens L2 is made of plastic, the third lens L3 is made of plastic, the fourth lens L4 is made of plastic, the fifth lens L5 is made of plastic, and the sixth lens L6 is made of plastic. Each lens may be made of a different material.

[0019] The fourth lens L4 is an aspherical prism with a reflecting surface RS on it. The light emitted from the image-side surface of the third lens L3 is reflected and refracted by the reflecting surface RS of the fourth lens L4, and then emitted from the image-side surface of the fourth lens L4. The folded optical path design allows the thickness of the device to be reduced.

[0020] When the focal length of the second lens L2 is f2 and the focal length of the third lens L3 is f3, the relationship -4.00≦f2 / f3≦-1.20 is established. If the focal lengths of the two lenses are close to each other within this relationship, the light rays will transition smoothly, improving the image quality.

[0021] When the field of view of the above imaging optical lens is FOV, the focal length is f, and the image height of the entire field of view is IH, the following relationship is established: 95.00≦(FOV×f) / IH≦101.632. If the range of this relationship is met, a wide field of view and telephoto capabilities can be achieved, ensuring mid- to long-distance imaging.

[0022] When the focal length of the first lens L1 is f1, the relational expression -2.50≦f1 / f≦-1.50 is established. If the ratio of the focal length of the first lens L1 to the focal length of the imaging optical lens is within this relational expression, it helps to guarantee the amount of incident light.

[0023] When the Abbe number of the second lens L2 is v2 and the Abbe number of the third lens L3 is v3, the relationship v3-v2≧30.00 is established, which specifies the difference in dispersion coefficients of the materials of the second and third adjacent lenses. Within this relationship, the chromatic aberration of the system can be effectively balanced, and the chromatic aberration |LC|≦3.5μm.

[0024] When the central radius of curvature of the object-side surface of fifth lens L5 is R9 and the central radius of curvature of the image-side surface of fifth lens L5 is R10, the relational expression 2.00≦R9 / R10≦5.00 is established, and the shape of fifth lens L5 is specified. Being within the range of this relational expression is advantageous for correcting astigmatism and distortion of the imaging optical lens, and distortion aberration |Distortion|≦2.2% is achieved, reducing the occurrence of vignetting.

[0025] When the focal length of the sixth lens element L6 is f6 and the on-axis thickness of the sixth lens element L6 is d11, the relationship 20.00≦f6 / d11≦60.00 is established, which specifies the ratio of the refractive power to the on-axis thickness of the sixth lens element L6. When the ratio is within the range of this relationship, the sixth lens element L6 maintains a sufficiently strong positive refractive power to contribute to correcting off-axis aberrations at the image-side edge, and the overall optical length can be effectively shortened to achieve the goal of miniaturization, further expanding the range of application of the product.

[0026] When the half aperture of the object-side surface of the first lens L1 is SD11, the relational expression SD11 / IH≦0.31 is established, which specifies the ratio of the head dimension and image height of the imaging optical lens. If the ratio is within the range of this relational expression, a small head design can be achieved.

[0027] When the above-mentioned relationship formulas are satisfied, the imaging optical lenses 10, 20, 30, 40, and 50 have good optical performance and can meet the design requirements for wide angles. Due to the characteristics of the imaging optical lenses 10, 20, 30, 40, and 50, they are particularly suitable for use as imaging lens components for mobile phones and web imaging lenses that are configured with imaging devices such as high-pixel CCDs and CMOSs.

[0028] Based on the above relationships and feasible functions, the characteristics of each lens are further refined as follows:

[0029] The first lens L1 has a surface on its object side that is convex or concave paraxially, a surface on its image side that is concave paraxially, and has negative refractive power. The surface shapes of the object side and image side surfaces of the first lens L1 may be other concave / convex distribution shapes.

[0030] When the central radius of curvature of the object-side surface of the first lens L1 is R1 and the central radius of curvature of the image-side surface of the first lens L1 is R2, the following relationship is established: 0.49≦(R1+R2) / (R1-R2)≦1.59. By rationally controlling the shape of the first lens L1, the first lens L1 can effectively correct the spherical aberration of the system. It is also preferable that the relationship be 0.78≦(R1+R2) / (R1-R2)≦1.27.

[0031] When the axial thickness of the first lens L1 is d1 and the total optical length of the imaging optical lens 10 is TTL, the relational expression 0.01≦d1 / TTL≦0.05 is established. Being within the range of this relational expression is advantageous for achieving compactness. Furthermore, it is preferable that 0.02≦d1 / TTL≦0.04.

[0032] The second lens L2 has a paraxially convex object-side surface and a paraxially concave image-side surface, and has negative refractive power. The surface shapes of the object-side and image-side surfaces of the second lens L2 may be other concave / convex distribution forms.

[0033] When the focal length of the imaging optical lens is f and the focal length of the second lens L2 is f2, the relationship -7.55≦f2 / f≦-0.87 is established. Controlling the negative refractive power of the second lens L2 within an appropriate range is advantageous for correcting aberrations in the optical system. Furthermore, it is preferable that the relationship be -4.72≦f2 / f≦-1.08.

[0034] 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 relational expression 1.30≦(R3+R4) / (R3-R4)≦6.59 is established, and the shape of the second lens L2 is specified based on this relational expression. As lenses become thinner and wider in angle, being within the range of this relational expression is advantageous for correcting problems such as axial chromatic aberration. It is also preferable that 2.08≦(R3+R4) / (R3-R4)≦5.27.

[0035] When the axial thickness of the second lens L2 is d3 and the total optical length of the imaging optical lens 10 is TTL, the following relationship is established: 0.06≦d3 / TTL≦0.24. Being within this relationship is advantageous for achieving compactness. Furthermore, it is preferable that 0.10≦d3 / TTL≦0.20.

[0036] The third lens L3 has a paraxially convex object-side surface and a paraxially concave image-side surface, and has positive refractive power. The surface shapes of the object-side and image-side surfaces of the third lens L3 may be other concave / convex distribution shapes.

[0037] When the focal length of the imaging optical lens is f and the focal length of the third lens L3 is f3, the relationship 0.48≦f3 / f≦1.63 is established. By appropriately allocating the refractive power, the system has excellent imaging quality and low sensitivity. It is also preferable that 0.76≦f3 / f≦1.30.

[0038] When the central radius of curvature of the object-side surface of the third lens L3 is R5 and the central radius of curvature of the image-side surface of the third lens L3 is R6, the following relationship is established: -3.38≦(R5+R6) / (R5-R6)≦-0.93. Within this range, the shape of the third lens L3 can be effectively controlled, which is advantageous for molding the third lens L3 and prevents molding defects and stress caused by excessive curvature of the surface of the third lens L3. It is also preferable that -2.11≦(R5+R6) / (R5-R6)≦-1.17.

[0039] When the axial thickness of the third lens L3 is d5 and the total optical length of the imaging optical lens 10 is TTL, the following relationship is established: 0.04≦d5 / TTL≦0.14. Being within the range of this relationship is advantageous for achieving compactness. Furthermore, it is preferable that 0.06≦d5 / TTL≦0.11.

[0040] The fourth lens L4 has a paraxially convex object-side surface and a paraxially convex image-side surface, and has positive refractive power. The surface shapes of the object-side and image-side surfaces of the fourth lens L4 may be other concave / convex distribution shapes.

[0041] When the focal length of the imaging optical lens is f and the focal length of the fourth lens L4 is f4, the relationship 0.38≦f4 / f≦1.38 is established. By appropriately allocating the refractive power, the system has excellent imaging quality and low sensitivity. It is also preferable that 0.61≦f4 / f≦1.11.

[0042] When the central radius of curvature of the object-side surface of the fourth lens L4 is R7 and the central radius of curvature of the image-side surface of the fourth lens L4 is R8, the relational expression 0.50≦(R7+R8) / (R7-R8)≦1.50 is established, and the shape of the fourth lens L4 is specified based on this relational expression. As lenses become thinner and wider in angle of view, being within the range of this relational expression is advantageous for correcting problems such as aberrations at off-axial angles of view. It is also preferable that 0.80≦(R7+R8) / (R7-R8)≦1.20.

[0043] When the axial thickness of the fourth lens L4 is d7 and the total optical length of the imaging optical lens 10 is TTL, the following relationship is established: 0.18≦d7 / TTL≦0.61. Being within this relationship is advantageous for achieving compactness. Furthermore, it is preferable that 0.28≦d7 / TTL≦0.49.

[0044] The fifth lens L5 has a paraxially convex object-side surface and a paraxially concave image-side surface, and has negative refractive power. The surface shapes of the object-side and image-side surfaces of the fifth lens L5 may be other concave / convex distribution shapes.

[0045] When the focal length of the imaging optical lens is f and the focal length of the fifth lens L5 is f5, the relational expression -8.15≦f5 / f≦-1.51 is established. By limiting the size of the fifth lens L5, the ray angle of the imaging optical lens 10 can be made gentler, reducing tolerance sensitivity. It is also preferable that -5.09≦f5 / f≦-1.89.

[0046] When the central radius of curvature of the object-side surface of the fifth lens L5 is R9 and the central radius of curvature of the image-side surface of the fifth lens L5 is R10, the relational expression 0.75≦(R9+R10) / (R9-R10)≦4.48 is established, and the shape of the fifth lens L5 is specified. Being within the range of this relational expression is advantageous for correcting problems such as aberrations in the off-axial angle of view as lenses become increasingly thin and wider in angle of view. It is also preferable that 1.20≦(R9+R10) / (R9-R10)≦3.58.

[0047] When the axial thickness of the fifth lens L5 is d9 and the total optical length of the imaging optical lens 10 is TTL, the relational expression 0.01≦d9 / TTL≦0.05 is established. Being within the range of this relational expression is advantageous for achieving compactness. Furthermore, it is preferable that 0.02≦d9 / TTL≦0.04.

[0048] The sixth lens L6 has a paraxially convex object-side surface and a paraxially concave image-side surface, and has positive refractive power. The surface shapes of the object-side and image-side surfaces of the sixth lens L6 may be other concave / convex distribution shapes.

[0049] When the focal length of the imaging optical lens is f and the focal length of the sixth lens L6 is f6, the relationship 1.26≦f6 / f≦11.21 is established, and the refractive power is reasonably distributed, resulting in excellent imaging quality and low sensitivity as a system. It is also preferable that 2.02≦f6 / f≦8.97.

[0050] When the central radius of curvature of the object-side surface of the sixth lens L6 is R11 and the central radius of curvature of the image-side surface of the sixth lens L6 is R12, the relational expression -294.00≦(R11+R12) / (R11-R12)≦655.50 is established, and the shape of the sixth lens L6 is defined accordingly. Being within the range of this relational expression is advantageous for correcting problems such as aberrations at off-axial angles of view as lenses become increasingly thin and wider in angle of view. It is also preferable that -183.75≦(R11+R12) / (R11-R12)≦524.40.

[0051] When the axial thickness of the sixth lens L6 is d11 and the total optical length of the imaging optical lens 10 is TTL, the relational expression 0.03≦d11 / TTL≦0.10 is established. Being within the range of this relational expression is advantageous for achieving compactness. Furthermore, it is preferable that 0.04≦d11 / TTL≦0.08.

[0052] When the image height of the imaging optical lens is IH and the total optical length of the imaging optical lens is TTL, the relational expression TTL / IH≦3.10 is established. This is advantageous for achieving an extremely thin lens. Furthermore, it is preferable that TTL / IH≦3.04.

[0053] The field of view FOV of the above imaging optical lens is 66.00° or more, which allows for a wide angle of view.

[0054] The aperture value FNO of the above imaging optical lens is 2.50 or less, which allows for a large aperture and ensures excellent imaging performance of the imaging optical lens.

[0055] The imaging optical lens according to the present invention will be described below using examples. The symbols used in each example are as follows: focal length, axial distance, central radius of curvature, axial thickness, inflection point position, and stationary point position are all in mm.

[0056] TTL: total optical length (axial distance from the object-side surface of the first lens L1 to the image plane Si), in mm.

[0057] FNO: The ratio of the effective focal length of an imaging optical lens to the entrance pupil diameter.

[0058] Preferably, in order to obtain high-quality imaging performance, an inflection point and / or a stationary point may be further provided on the object-side surface and / or the image-side surface of the lens.

[0059] The technical solution of the present invention will be specifically described below using five embodiments, and comparative embodiments are provided for reference. If the above relationship range is exceeded, the technical effect of the present invention cannot be achieved. (First embodiment)

[0060] Tables 1 and 2 show setting data for the imaging optical lens 10 according to the first embodiment of the present invention.

[0061] [Table 1]

[0062] Here, the meanings of the symbols are as follows: S1: Aperture R: Radius of curvature at the center of the optical surface R1: Radius of curvature of the center of the object-side surface of the first lens L1 R2: Radius of central curvature of the image-side surface of the first lens L1 R3: Radius of curvature of the center of the object-side surface of the second lens L2 R4: Radius of central curvature of the image-side surface of the second lens L2 R5: Radius of central curvature of the object-side surface of the third lens L3 R6: Radius of central curvature of the image-side surface of the third lens L3 R7: Radius of curvature of the center of the object-side surface of the fourth lens L4 R8: Radius of central curvature of the image-side surface of the fourth lens L4 R9: Radius of curvature of the center of the object-side surface of the fifth lens element L5 R10: Radius of central curvature of the image-side surface of the fifth lens L5 R11: Radius of central curvature of the object-side surface of the sixth lens element L6 R12: Radius of central curvature of the image-side surface of the sixth lens L6 R13: Radius of curvature at the center of the object-side surface of the optical filter GF R14: Radius of central curvature of the image-side surface 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 surface 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 element 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 element 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 element L4 d8: The axial distance from the image-side surface of the fourth lens L4 to the object-side surface of the fifth lens L5 d9: Axial thickness of the fifth lens element L5 d10: The axial distance from the image-side surface of the fifth lens L5 to the object-side surface of the sixth lens L6 d11: Axial thickness of the sixth lens element L6 d12: The axial distance from the image-side surface of the sixth lens element L6 to the object-side surface of the optical filter GF d13: On-axis thickness of optical filter GF d14: The axial distance from the image-side surface 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 third lens L3 at the d line nd4: Refractive index of the d line of the fourth lens element L4 nd5: Refractive index of the d line of the fifth lens L5 nd6: Refractive index of the d line of the sixth lens element L6 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 element L3 v4: Abbe number of the fourth lens element L4 v5: Abbe number of the fifth lens element L5 v6: Abbe number of the sixth lens element L6 vg: Abbe number of the optical filter GF

[0063] Table 2 shows data on the aspheric surfaces of each lens in the imaging optical lens 10 according to the first embodiment of the present invention.

[0064] [Table 2]

[0065] For convenience, the aspherical surface of each lens surface is an aspherical surface expressed by the following formula (1), but the present invention is not limited to the aspherical polynomial of formula (1).

[0066] 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 +A16r16 +A18r 18 +A20r 20 (1)

[0067] where k is the conic coefficient, A4, A6, A8, A10, A12, A14, A16, A18, and A20 are aspheric coefficients, c is the curvature of 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 from the optical axis and a tangent plane that touches the vertex on the aspheric optical axis).

[0068] Tables 3 and 4 show setting data for the inflection points and stationary points of each lens in the imaging optical lens 10 according to the first embodiment of the present invention. Here, P1R1 and P1R2 respectively represent the object-side and image-side surfaces of the first lens L1, P2R1 and P2R2 respectively represent the object-side and image-side surfaces of the second lens L2, P3R1 and P3R2 respectively represent the object-side and image-side surfaces of the third lens L3, P4R1 and P4R2 respectively represent the object-side and image-side surfaces of the fourth lens L4, P5R1 and P5R2 respectively represent the object-side and image-side surfaces of the fifth lens L5, and P6R1 and P6R2 respectively represent the object-side and image-side surfaces of the sixth lens L6. In addition, the corresponding data in the "Inflection Point Position" column is the vertical distance from the inflection point provided on the surface of each lens to the optical axis of the imaging optical lens 10, and the corresponding data in the "Stationary Point Position" column is the vertical distance from the stationary point provided on the surface of each lens to the optical axis of the imaging optical lens 10.

[0069] [Table 3]

[0070] [Table 4]

[0071] 2 and 3 are diagrams showing the spherical aberration and chromatic aberration of magnification of light with wavelengths of 650 nm, 610 nm, 550 nm, 490 nm, 470 nm, and 430 nm, respectively, after passing through the imaging optical lens 10 according to the first embodiment. Fig. 4 is a diagram showing the curvature of field and distortion aberration of light with a wavelength of 550 nm after passing through the imaging optical lens 10 according to the first embodiment, where the curvature of field S in Fig. 4 is the curvature of field in the sagittal direction and T is the curvature of field in the meridional direction.

[0072] In this embodiment, the imaging optical lens 10 has an entrance pupil diameter ENPD of 1.325 mm, a full field of view image height IH of 2.300 mm, and a diagonal angle of view FOV of 70.00°. The imaging optical lens 10 satisfies the design requirements for a large aperture, an extremely thin design, a wide angle of view, and a small head, and its on-axis and off-axis chromatic aberrations are sufficiently corrected, resulting in excellent optical characteristics. (Second embodiment)

[0073] In the second embodiment, the meanings of the symbols are the same as in the first embodiment.

[0074] Shown in FIG. 5 is an imaging optical lens 20 according to a second embodiment of the present invention.

[0075] Tables 5 and 6 show setting data for the imaging optical lens 20 according to the second embodiment of the present invention.

[0076] [Table 5]

[0077] Table 6 shows data on the aspheric surfaces of the lenses in the imaging optical lens 20 according to the second embodiment of the present invention.

[0078] [Table 6]

[0079] Tables 7 and 8 show the setting data of the inflection points and stationary points of each lens in the imaging optical lens 20 according to the second embodiment of the present invention.

[0080] [Table 7]

[0081] [Table 8]

[0082] 6 and 7 are diagrams showing spherical aberration and lateral chromatic aberration of light with wavelengths of 650 nm, 610 nm, 550 nm, 490 nm, 470 nm, and 430 nm, respectively, after passing through the imaging optical lens 20 according to the second embodiment. Fig. 8 is a diagram showing field curvature and distortion aberration of light with a wavelength of 550 nm after passing through the imaging optical lens 20 according to the second embodiment. In Fig. 8, field curvature S is the field curvature in the sagittal direction, and T is the field curvature in the meridional direction.

[0083] In this embodiment, the imaging optical lens 20 has an entrance pupil diameter ENPD of 1.206 mm, a full field of view image height IH of 2.300 mm, and a diagonal angle of view FOV of 72.85°. The imaging optical lens 20 satisfies the design requirements for a large aperture, an extremely thin design, a wide angle of view, and a small head, and its on-axis and off-axis chromatic aberrations are sufficiently corrected, resulting in excellent optical characteristics. (Third embodiment)

[0084] In the third embodiment, the meanings of the symbols are the same as in the first embodiment.

[0085] Shown in FIG. 9 is an imaging optical lens 30 according to a third embodiment of the present invention.

[0086] Tables 9 and 10 show setting data for the imaging optical lens 30 according to the third embodiment of the present invention.

[0087] [Table 9]

[0088] Table 10 shows data on the aspheric surfaces of the lenses in the imaging optical lens 30 according to the third embodiment of the present invention.

[0089] [Table 10]

[0090] Tables 11 and 12 show the setting data of the inflection points and stationary points of each lens in the imaging optical lens 30 according to the third embodiment of the present invention.

[0091] [Table 11]

[0092] [Table 12]

[0093] 10 and 11 are diagrams showing spherical aberration and chromatic aberration of magnification of light with wavelengths of 650 nm, 610 nm, 550 nm, 490 nm, 470 nm, and 430 nm, respectively, after passing through the imaging optical lens 30 according to the third embodiment. Fig. 12 is a diagram showing field curvature and distortion aberration of light with a wavelength of 550 nm after passing through the imaging optical lens 30 according to the third embodiment. In Fig. 12, field curvature S is the field curvature in the sagittal direction, and field curvature T is the field curvature in the meridional direction.

[0094] In this embodiment, the imaging optical lens 30 has an entrance pupil diameter ENPD of 1.357 mm, an image height IH of the entire field of view of 2.300 mm, and a diagonal angle of view FOV of 69.16°. The imaging optical lens 30 satisfies the design requirements for a large aperture, an extremely thin design, a wide angle of view, and a small head, and its on-axis and off-axis chromatic aberrations are sufficiently corrected, resulting in excellent optical characteristics. (Fourth embodiment)

[0095] In the fourth embodiment, the meanings of the symbols are the same as in the first embodiment.

[0096] Shown in FIG. 13 is an imaging optical lens 40 according to a fourth embodiment of the present invention.

[0097] Tables 13 and 14 show setting data for the imaging optical lens 40 according to the fourth embodiment of the present invention.

[0098] [Table 13]

[0099] Table 14 shows data on the aspheric surfaces of the lenses in the imaging optical lens 40 according to the fourth embodiment of the present invention.

[0100] [Table 14]

[0101] Tables 15 and 16 show the setting data of the inflection points and stationary points of each lens in the imaging optical lens 40 according to the fourth embodiment of the present invention.

[0102] [Table 15]

[0103] [Table 16]

[0104] 14 and 15 are diagrams showing spherical aberration and lateral chromatic aberration of light with wavelengths of 650 nm, 610 nm, 550 nm, 490 nm, 470 nm, and 430 nm, respectively, after passing through the imaging optical lens 40 according to the fourth embodiment. Fig. 16 is a diagram showing field curvature and distortion aberration of light with a wavelength of 550 nm after passing 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 meridional direction.

[0105] In this embodiment, the imaging optical lens 40 has an entrance pupil diameter ENPD of 1.375 mm, a full field of view image height IH of 2.300 mm, and a diagonal angle of view FOV of 66.13°. The imaging optical lens 40 satisfies the design requirements for a large aperture, ultra-thinness, an ultra-wide angle, and a small head, and its on-axis and off-axis chromatic aberrations are sufficiently corrected, resulting in excellent optical characteristics. (Fifth embodiment)

[0106] In the fifth embodiment, the meanings of the symbols are the same as in the first embodiment.

[0107] Shown in FIG. 17 is an imaging optical lens 50 according to a fifth embodiment of the present invention.

[0108] Tables 17 and 18 show setting data for the imaging optical lens 50 according to the fifth embodiment of the present invention.

[0109] [Table 17]

[0110] Table 18 shows data on the aspheric surfaces of the lenses in the imaging optical lens 50 according to the fifth embodiment of the present invention.

[0111] [Table 18]

[0112] Tables 19 and 20 show the setting 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.

[0113] [Table 19]

[0114] [Table 20]

[0115] 18 and 19 are diagrams showing spherical aberration and chromatic aberration of magnification, respectively, of light having wavelengths of 650 nm, 610 nm, 550 nm, 490 nm, 470 nm, and 430 nm after passing through the imaging optical lens 50 according to the fifth embodiment. Fig. 20 is a diagram showing field curvature and distortion aberration of light having a wavelength of 550 nm after passing through the imaging optical lens 50 according to the fifth embodiment. In Fig. 20, field curvature S is the field curvature in the sagittal direction, and T is the field curvature in the meridional direction.

[0116] In this embodiment, the imaging optical lens 50 has an entrance pupil diameter ENPD of 1.268 mm, a full field of view image height IH of 2.300 mm, and a diagonal angle of view FOV of 70.55°. The imaging optical lens 50 satisfies the design requirements for a large aperture, ultra-thinness, an ultra-wide angle, and a small head, and its on-axis and off-axis chromatic aberrations are sufficiently corrected, resulting in excellent optical characteristics.

[0117] Table 25 below shows the values corresponding to the parameters defined by the numerical values and relational expressions of the first, second, third, fourth and fifth embodiments. (Comparative embodiment)

[0118] In the comparative embodiment, the symbols have the same meanings as in the first embodiment.

[0119] FIG. 21 shows an imaging optical lens 60 according to a comparative embodiment.

[0120] Tables 21 and 22 show setting data for the imaging optical lens 60 according to the comparative embodiment.

[0121] [Table 21]

[0122] Table 22 shows data on the aspheric surfaces of the lenses in the imaging optical lens 60 according to the comparative embodiment.

[0123] [Table 22]

[0124] Tables 23 and 24 show the setting data of the inflection points and stationary points of each lens in the imaging optical lens 60 according to the comparative embodiment.

[0125] [Table 23]

[0126] [Table 24]

[0127] 22 and 23 are diagrams showing spherical aberration and chromatic aberration of magnification after light having wavelengths of 650 nm, 610 nm, 550 nm, 490 nm, 470 nm, and 430 nm has passed through the imaging optical lens 60 according to the comparative embodiment. Fig. 24 is a diagram showing field curvature and distortion aberration after light having a wavelength of 550 nm has passed through the imaging optical lens 60 according to 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 meridional direction.

[0128] Below, the numerical values corresponding to each of the above relational expressions in the comparative embodiment are shown in Table 25. Clearly, the imaging optical lens 60 of the comparative embodiment does not satisfy the above relational expression 95.00≦(FOV×f) / IH≦101.632.

[0129] In the comparative embodiment, the entrance pupil diameter ENPD of the imaging optical lens 60 is 1.372 mm, the image height IH of the entire field of view is 2.300 mm, and the diagonal angle of view FOV is 69.97°. The imaging optical lens 60 does not satisfy the design requirements for a large aperture, ultra-thinness, an ultra-wide angle, and a small head.

[0130] [Table 25]

[0131] The above-described embodiments are specific embodiments for realizing the present invention, but it should be understood by those skilled in the art that in actual applications, various changes in form and details that do not deviate from the spirit and scope of the present invention will all fall within the scope of protection of the present invention.

Claims

1. An imaging optical lens including a total of six lenses, the six lenses being, in order from the object side to the image side, a first lens having negative refractive power, a second lens having negative refractive power, a third lens having positive refractive power, a fourth lens having positive refractive power, a fifth lens having negative refractive power, and a sixth lens having positive refractive power, wherein the fourth lens is a prism, and the imaging optical lens satisfies the following relational expression when the focal length of the second lens is f2, the focal length of the third lens is f3, the angle of view of the imaging optical lens is FOV, the focal length of the imaging optical lens is f, and the image height of the entire field of view of the imaging optical lens is IH. -4.00≦f2 / f3≦-1.20 95.00≦(FOV×f) / IH≦101.632

2. 2. The imaging optical lens according to claim 1, wherein the following relational expression is satisfied when the focal length of the first lens is f1: −2.50≦f1 / f≦−1.50

3. 2. The imaging optical lens according to claim 1, wherein the following relational expression is satisfied when the Abbe number of the second lens is v2 and the Abbe number of the third lens is v3. v3-v2≧30.00

4. 2. The imaging optical lens according to claim 1, wherein the following relational expression is satisfied when a central radius of curvature of an object-side surface of the fifth lens is R9 and a central radius of curvature of an image-side surface of the fifth lens is R10: 2.00≦R9 / R10≦5.00

5. 2. The imaging optical lens according to claim 1, wherein the following relational expression is satisfied when the focal length of the sixth lens is f6 and the axial thickness of the sixth lens is d11. 20.00≦f6 / d11≦60.00

6. 2. The imaging optical lens according to claim 1, wherein the following relational expression is satisfied when the half aperture of the object-side surface of the first lens is SD11: SD11 / IH≦0.31

7. the first lens has an image-side surface formed as a concave surface paraxially; 2. The imaging optical lens according to claim 1, wherein the following relational expression is satisfied when a central radius of curvature of an object-side surface of the first lens is R1, a central radius of curvature of an image-side surface of the first lens is R2, an axial thickness of the first lens is d1, and a total optical length of the imaging optical lens is TTL: 0.49≦(R1+R2) / (R1-R2)≦1.59 0.01≦d1 / TTL≦0.05

8. the second lens has an object-side surface formed as a convex surface paraxially, and an image-side surface formed as a concave surface paraxially; 2. The imaging optical lens according to claim 1, wherein the following relational expression is satisfied when a central radius of curvature of an object-side surface of the second lens is R3, a central radius of curvature of an image-side surface of the second lens is R4, an axial thickness of the second lens is d3, and a total optical length of the imaging optical lens is TTL: −7.55≦f2 / f≦−0.87 1.30≦(R3+R4) / (R3-R4)≦6.59 0.06≦d3 / TTL≦0.24

9. the third lens has an object-side surface formed as a convex surface paraxially, and an image-side surface formed as a concave surface paraxially; 2. The imaging optical lens according to claim 1, wherein the following relational expression is satisfied when 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, an axial thickness of the third lens is d5, and a total optical length of the imaging optical lens is TTL. 0.48≦f3 / f≦1.63 -3.38≦(R5+R6) / (R5-R6)≦-0.93 0.04≦d5 / TTL≦0.14

10. the fourth lens has an object-side surface formed as a convex surface paraxially, and an image-side surface formed as a convex surface paraxially, 2. The imaging optical lens according to claim 1, wherein the following relational expression is satisfied 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, an axial thickness of the fourth lens is d7, and a total optical length of the imaging optical lens is TTL. 0.38≦f4 / f≦1.38 0.50≦(R7+R8) / (R7-R8)≦1.50 0.18≦d7 / TTL≦0.61

Images