Imaging Optical Lens

Abstract

The present invention relates to the field of optical lenses and discloses an imaging optical lens. [Solution] The imaging optical lens 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 positive refractive power, a third lens having positive refractive power, a fourth lens having negative refractive power, a fifth lens having positive refractive power, and a sixth lens having negative refractive power; Here, 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 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 third lens is d5, the axial thickness of the fourth lens is d7, and the axial thickness of the fifth lens is d9, the following relational expressions are satisfied: 6.00≦R2 / R1≦25.00, 2.00≦(R7+R8) / (R7-R8)≦9.00, and 3.00≦(d5+d9) / d7≦9.00.

Description

[Technical field]

[0001] The present invention relates to the field of optical lenses, and more particularly to an imaging optical lens 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 is increasing, the pixel size of the photosensitive element is shrinking, and the current electronic products have high requirements for excellent functions and light, thin, and portable appearances, so that miniaturized imaging optical lenses with good imaging quality have already become mainstream in the current market. In order to obtain good imaging quality, lenses often use multiple lens structures. In addition, with the evolution of technology and the increase in diversification needs of users, the pixel area of ​​the photosensitive element is shrinking, and the requirements for the imaging quality of the system are increasing, so that a six-lens structure is gradually appearing in the design of lenses. Therefore, there is a growing demand for wide-angle imaging lenses with excellent optical properties, small volume, and sufficient correction of aberrations. 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, the 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 positive refractive power, a third lens having positive refractive power, a fourth lens having negative refractive power, a fifth lens having positive refractive power, and a sixth lens having negative refractive power, wherein, 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, 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 third lens is d5, an axial thickness of the fourth lens is d7, and an axial thickness of the fifth lens is d9, the following relational formula is satisfied: 6.00≦R2 / R1≦25.00 2.00≦(R7+R8) / (R7-R8)≦9.00 3.00≦(d5+d9) / d7≦9.00

[0005] Preferably, when the total optical length of the imaging optical lens is TTL and the focal length of the imaging optical lens is f, the following relational expression is satisfied. 2.00≦TTL / f≦2.30

[0006] Preferably, when the focal length of the sixth lens is f6 and the on-axis thickness of the sixth lens is d11, the following relational expression is satisfied. -6.00≦f6 / d11≦-3.00

[0007] Preferably, when the focal length of the second lens is f2 and the focal length of the third lens is f3, the following relational expression is satisfied. 2.50≦f2 / f3≦7.00.

[0008] Preferably, the first lens has an object-side surface formed as a concave surface paraxially, and an image-side surface formed as a convex surface paraxially, and satisfies the following relational expression when a focal length of the first lens is f1, a focal length of the imaging optical lens is f, an axial thickness of the first lens is d1, and a total optical length of the imaging optical lens is TTL: -5.26≦f1 / f≦-1.23 -2.80≦(R1+R2) / (R1-R2)≦-0.72 0.02≦d1 / TTL≦0.06

[0009] Preferably, 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, and satisfies the following relational expression when a focal length of the second lens is f2, a focal length of the imaging optical lens is f, a central radius of curvature of the object-side surface of the second lens is R3, a central radius of curvature of the 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: 1.50≦f2 / f≦11.95 -54.86≦(R3+R4) / (R3-R4)≦-4.92 0.03≦d3 / TTL≦0.11

[0010] Preferably, the third lens has an object-side surface formed as a convex surface paraxially, and an image-side surface formed as a convex surface paraxially, and satisfies the following relational expression when a focal length of the third lens is f3, a focal length of the imaging optical lens is f, 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 a total optical length of the imaging optical lens is TTL: 0.57≦f3 / f≦1.79 0.11≦(R5+R6) / (R5-R6)≦0.37 0.06≦d5 / TTL≦0.18

[0011] Preferably, the fourth 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 a focal length of the fourth lens is f4, a focal length of the imaging optical lens is f, and a total optical length of the imaging optical lens is TTL: -9.47≦f4 / f≦-2.92 0.03≦d7 / TTL≦0.09

[0012] Preferably, the fifth lens has an object-side surface formed as a concave surface paraxially, an image-side surface formed as a convex surface paraxially, and satisfies the following relational expression when a focal length of the fifth lens is f5, a focal length of the imaging optical lens is f, a central radius of curvature of the object-side surface of the fifth lens is R9, a central radius of curvature of the image-side surface of the fifth lens is R10, and a total optical length of the imaging optical lens is TTL: 0.29≦f5 / f≦0.89 0.83≦(R9+R10) / (R9-R10)≦2.60 0.09≦d9 / TTL≦0.26

[0013] Preferably, the sixth lens has an object-side surface formed as a convex surface paraxially, and an image-side surface formed as a concave surface paraxially, and satisfies the following relational expression when a focal length of the sixth lens is f6, a focal length of the imaging optical lens is f, a central radius of curvature of the object-side surface of the sixth lens is R11, a central radius of curvature of the image-side surface of the sixth lens is R12, an axial thickness of the sixth lens is d11, and a total optical length of the imaging optical lens is TTL: -1.44≦f6 / f≦-0.48 0.89≦(R11+R12) / (R11-R12)≦2.74 0.04≦d11 / TTL≦0.13 Effect 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, and a wide angle, and is particularly applicable to imaging lens components of mobile phones and web imaging lenses that are composed of imaging elements such as CCDs and CMOSs ​​for high pixel counts. [Brief description of the drawings]

[0015] In order to more clearly describe the technical ideas in the embodiments of the present invention, the drawings necessary for describing the embodiments are briefly described below. 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 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. [Diagram 2] FIG. 2 is a diagram showing spherical aberration of the imaging optical lens shown in FIG. [Diagram 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. [Diagram 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 comparative embodiment. [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. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[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. However, in each embodiment of the present invention, many technical details are described for the sake of easy understanding of the present invention, but 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] 1 to 16, the technical solution of the present invention provides imaging optical lenses 10, 20, 30, 40. FIGS. 1, 5, 9, 13 show the imaging optical lenses 10, 20, 30, 40 of the present invention, which include a total of six lenses. Specifically, the imaging optical lenses include, in order from the object side to the image side, a first lens L1, a second lens L2, an aperture S1, 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 surface 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 other materials.

[0019] 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 relational expression of 6.00≦R2 / R1≦25.00 is established, and the shape of the first lens L1 is regulated. If the range of this relational expression is satisfied, it is advantageous for correcting the astigmatism and distortion of the imaging optical lens, and the possibility of vignetting is reduced.

[0020] 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 2.00≦(R7+R8) / (R7-R8)≦9.00 is established, and the shape of the fourth lens L4 is regulated. If it is within the range of this relational expression, the degree of deviation of the light beam passing through the lens can be mitigated, and chromatic aberration can be effectively corrected.

[0021] When the axial thickness of the third lens L3 is d5, the axial thickness of the fourth lens L4 is d7, and the axial thickness of the fifth lens L5 is d9, the relational expression 3.00≦(d5+d9) / d7≦9.00 is established, and the ratio of the sum of the axial thickness of the third lens L3 and the axial thickness of the fifth lens L5 to the axial thickness of the fourth lens L4 is specified. If it is within the range of this relational expression, it contributes to shortening the overall optical length of the imaging optical lens, and realizes the effect of extremely thinning.

[0022] When the optical total length of the imaging optical lens is TTL and the focal length of the imaging optical lens is f, the relational expression 2.00≦TTL / f≦2.30 is established, and the ratio between the optical total length and the focal length of the imaging optical lens is specified. If it is within the range of this relational expression, it is favorable for rationally distributing the thickness of each lens in the system and more rationally distributing the refractive power.

[0023] When the focal length of the sixth lens L6 is f6 and the axial thickness of the sixth lens L6 is d11, the following relation is established: -6.00≦f6 / d11≦-3.00, which specifies the ratio of the focal length of the sixth lens L6 to its axial thickness. Being within the range of this relation is favorable for balancing the lens thickness and rationally distributing the refractive power of the lens.

[0024] When the focal length of the second lens L2 is f2 and the focal length of the third lens L3 is f3, the relational expression 2.50≦f2 / f3≦7.00 is established, and the ratio of the focal length of the second lens L2 to the focal length of the third lens L3 is specified. If it is within the range of this relational expression, the distribution of refractive power can be effectively balanced.

[0025] When the above-mentioned relational expressions are satisfied, the imaging optical lenses 10, 20, 30, 40 have good optical performance and can meet the design requirements for wide-angle. According to the characteristics of the imaging optical lenses 10, 20, 30, 40, the imaging optical lenses 10, 20, 30, 40 can be applied to imaging lens components of mobile phones and WEB imaging lenses, which are particularly configured with imaging elements such as CCD and CMOS for high pixel counts.

[0026] Based on the above relationships and feasible functions, the characteristics of each lens are further refined as follows:

[0027] The first lens L1 has a surface on the object side that is concave on the paraxial direction, a surface on the image side that is convex on the paraxial direction, and has negative refractive power. The surface shapes of the object side surface and the image side surface of the first lens L1 may be other concave and convex distribution shapes.

[0028] When the focal length of the imaging optical lens is f and the focal length of the first lens L1 is f1, the relational expression of -5.26≦f1 / f≦-1.23 is established, and the ratio of the negative refractive power of the first lens L1 to the overall focal length is specified. If it is within the range of this relational expression, the first lens L1 has an appropriate negative refractive power, which is advantageous for reducing the aberration of the system and is advantageous for making the lens extremely thin and widening the angle. In addition, it is preferable that -3.29≦f1 / f≦-1.54.

[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 L1 is R2, the relational expression of -2.80≦(R1+R2) / (R1-R2)≦-0.72 is established. By controlling the shape of the first lens L1 reasonably, the first lens L1 can effectively correct the spherical aberration of the system. In addition, it is preferable that -1.75≦(R1+R2) / (R1-R2)≦-0.90.

[0030] 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 following relation is established: 0.02≦d1 / TTL≦0.06. If the relation is within the range of this relation, it is advantageous for realizing compactness. In addition, it is preferable that 0.02≦d1 / TTL≦0.05.

[0031] The second lens L2 has a positive refractive power, its object side surface is formed as a convex surface on the paraxial direction, and its image side surface is formed as a concave surface on the paraxial direction. The surface shapes of the object side surface and the image side surface of the second lens L2 may be other concave / convex distribution shapes.

[0032] When the focal length of the imaging optical lens is f and the focal length of the second lens L2 is f2, the relational expression of 1.50≦f2 / f≦11.95 is established. By controlling the positive refractive power of the second lens L2 within an appropriate range, it is advantageous to correct the aberration of the optical system. In addition, it is preferable that 2.40≦f2 / f≦9.56.

[0033] When the radius of curvature of the center of the object side surface of the second lens L2 is R3 and the radius of curvature of the center of the image side surface of the second lens L2 is R4, the relational expression of -54.86≦(R3+R4) / (R3-R4)≦-4.92 is established, and the shape of the second lens L2 is regulated. If it is within the range of this relational expression, it is advantageous for correcting problems such as axial chromatic aberration as the lens becomes extremely thin and wide-angle. In addition, it is preferable that -34.29≦(R3+R4) / (R3-R4)≦-6.15.

[0034] When the axial thickness of the second lens L2 is d3 and the optical total length of the imaging optical lens 10 is TTL, the relational expression 0.03≦d3 / TTL≦0.11 is established. If the relational expression is within the range, it is advantageous for realizing compactness. In addition, it is preferable that 0.05≦d3 / TTL≦0.09.

[0035] The third lens L3 has a positive refractive power, the object side surface of which is convex on the paraxial direction, and the image side surface of which is convex on the paraxial direction. The surface shapes of the object side surface and the image side surface of the third lens L3 may be other concave and convex distribution shapes.

[0036] When the focal length of the imaging optical lens is f and the focal length of the third lens L3 is f3, the relational expression of 0.57≦f3 / f≦1.79 is established. By appropriately allocating the refractive power, the system has excellent imaging quality and low sensitivity. In addition, it is preferable that 0.92≦f3 / f≦1.44.

[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, the following relation is established: 0.11≦(R5+R6) / (R5-R6)≦0.37. Within the range of this relation, the shape of the third lens L3 can be effectively controlled, which is advantageous for molding the third lens L3 and can prevent molding defects and stress caused by the surface curvature of the third lens L3 being too large. In addition, it is preferable that 0.18≦(R5+R6) / (R5-R6)≦0.29.

[0038] When the axial thickness of the third lens L3 is d5 and the optical total length of the imaging optical lens 10 is TTL, the following relation is established: 0.06≦d5 / TTL≦0.18. If the relation is within the range of this relation, it is advantageous for realizing compactness. In addition, it is preferable that 0.09≦d5 / TTL≦0.14.

[0039] The fourth lens L4 has a surface on the object side that is convex on the paraxial direction, a surface on the image side that is concave on the paraxial direction, and has negative refractive power. The surface shapes of the object side surface and the image side surface of the fourth lens L4 may be other concave and convex distribution shapes.

[0040] When the focal length of the imaging optical lens is f and the focal length of the fourth lens L4 is f4, the relational expression of -9.47≦f4 / f≦-2.92 is established. By appropriately allocating the refractive power, the system has excellent imaging quality and low sensitivity. In addition, it is preferable that -5.92≦f4 / f≦-3.65.

[0041] When the axial thickness of the fourth lens L4 is d7 and the optical total length of the imaging optical lens 10 is TTL, the relational expression 0.03≦d7 / TTL≦0.09 is established. If the relational expression is within the range, it is advantageous for realizing compactness. In addition, it is preferable that 0.04≦d7 / TTL≦0.07.

[0042] The fifth lens L5 has a positive refractive power, its object side surface is formed as a paraxial concave surface, its image side surface is formed as a paraxial convex surface, and the surface shapes of the object side surface and the image side surface of the fifth lens L5 may be other concave and convex distribution shapes.

[0043] 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 0.29≦f5 / f≦0.89 is established. By limiting the fifth lens L5, the light ray angle of the imaging optical lens 10 can be made gentler, and the tolerance sensitivity can be reduced. In addition, it is preferable that 0.46≦f5 / f≦0.71.

[0044] When the radius of curvature of the object side surface of the fifth lens L5 is R9 and the radius of curvature of the image side surface of the fifth lens L5 is R10, the relational expression of 0.83≦(R9+R10) / (R9-R10)≦2.60 is established, and the shape of the fifth lens L5 is specified. If it is within the range of this relational expression, it is advantageous for correcting problems such as aberrations of off-axis angles of view as the lens becomes extremely thin and wide-angle. In addition, it is preferable that 1.33≦(R9+R10) / (R9-R10)≦2.08.

[0045] When the axial thickness of the fifth lens L5 is d9 and the optical total length of the imaging optical lens 10 is TTL, the following relation is established: 0.09≦d9 / TTL≦0.26. If the relation is within the range of this relation, it is advantageous for realizing compactness. In addition, it is preferable that 0.14≦d9 / TTL≦0.21.

[0046] The sixth lens L6 has a negative refractive power, its object side surface is formed as a convex surface on the paraxial direction, and its image side surface is formed as a concave surface on the paraxial direction. The surface shapes of the object side surface and the image side surface of the sixth lens L6 may be other concave and convex distribution shapes.

[0047] When the focal length of the imaging optical lens is f and the focal length of the sixth lens L6 is f6, the relational expression of -1.44≦f6 / f≦-0.48 is established, and the refractive power is reasonably distributed, so that the system has excellent imaging quality and low sensitivity. It is also preferable that -0.90≦f6 / f≦-0.59.

[0048] When the radius of curvature of the center of the surface of the sixth lens L6 on the object side is R11 and the radius of curvature of the center of the surface of the sixth lens L6 on the image side is R12, the relational expression of 0.89≦(R11+R12) / (R11-R12)≦2.74 is established, and the shape of the sixth lens L6 is specified. If it is within the range of this relational expression, it is advantageous for correcting problems such as aberrations of the off-axis angle of view as the lens becomes extremely thin and wide-angle. In addition, it is preferable that 1.42≦(R11+R12) / (R11-R12)≦2.19.

[0049] When the axial thickness of the sixth lens L6 is d11 and the optical total length of the imaging optical lens 10 is TTL, the relational expression 0.04≦d11 / TTL≦0.13 is established. If the relational expression is within the range, it is advantageous for realizing compactness. In addition, it is preferable that 0.07≦d11 / TTL≦0.11.

[0050] When the image height of the imaging optical lens is IH and the total optical length of the imaging optical lens is TTL, the relation TTL / IH≦2.39 is established. This is advantageous for realizing a very thin lens. It is also preferable that TTL / IH≦1.91.

[0051] The field of view FOV of the above imaging optical lens is 100.00° or more. This allows a wide angle to be realized.

[0052] The aperture value FNO of the imaging optical lens is 2.26 or less. This allows a large aperture to be achieved, and the imaging performance of the imaging optical lens is excellent. It is also preferable that the aperture value FNO of the imaging optical lens is 2.22 or less.

[0053] The imaging optical lens according to the present invention will be described below using examples. The symbols used in each example are as follows. The units of the focal length, axial distance, central radius of curvature, axial thickness, inflection point position, and stationary point position are mm.

[0054] TTL: total optical length (the axial distance from the object-side surface of the first lens L1 to the image plane Si), in mm.

[0055] Aperture No. FNO: The ratio of the effective focal length of an imaging optical lens to the entrance pupil diameter.

[0056] Preferably, in order to obtain high quality imaging performance, the lens may further be provided with an inflection point and / or a stationary point on the object side surface and / or the image side surface.

[0057] The technical solution of the present invention will be specifically described below using four 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)

[0058] Tables 1 and 2 show setting data of the imaging optical lens 10 according to the first embodiment of the present invention.

[0059] [Table 1]

[0060] 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 curvature of the center 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 L5 R10: Radius of central curvature of the image-side surface of the fifth lens L5 R11: Radius of curvature of the center of the object side surface of the sixth lens L6 R12: Radius of central curvature of the image-side surface of the sixth lens L6 R13: Radius of curvature of 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 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 aperture stop S1 ds: The axial distance from the aperture stop S1 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 fifth lens L5 d9: Axial thickness of the fifth lens 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 L6 d12: The axial distance from the image-side surface of the sixth lens L6 to the object-side surface of the optical filter GF d13: Axial 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 d line of the third lens L3 nd4: Refractive index of the d line of the fourth lens L4 nd5: Refractive index of the d line of the fifth lens L5 nd6: Refractive index of the d line of the sixth lens 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 L3 v4: Abbe number of the fourth lens L4 v5: Abbe number of the fifth lens L5 v6: Abbe number of the sixth lens L6 vg: Abbe number of the optical filter GF

[0061] 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.

[0062] [Table 2]

[0063] For convenience, the aspheric surface of each lens surface is expressed by the following formula (1), but the present invention is not limited to the aspheric polynomial of this formula (1).

[0064] 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 +A18r 18 +A20r20 (1)

[0065] where k is the conic coefficient, A4, A6, A8, A10, A12, A14, A16, A18, A20 are aspheric coefficients, c is the central curvature 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 the tangent plane that is tangent to the vertex on the aspheric optical axis).

[0066] Tables 3 and 4 show setting data of 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 indicate the object side surface and image side surface of the first lens L1, P2R1 and P2R2 respectively indicate the object side surface and image side surface of the second lens L2, P3R1 and P3R2 respectively indicate the object side surface and image side surface of the third lens L3, P4R1 and P4R2 respectively indicate the object side surface and image side surface of the fourth lens L4, P5R1 and P5R2 respectively indicate the object side surface and image side surface of the fifth lens L5, and P6R1 and P6R2 respectively indicate the object side surface and image side surface 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 “Standing 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.

[0067] [Table 3]

[0068] [Table 4]

[0069] Fig. 2 and Fig. 3 are diagrams showing spherical aberration and lateral chromatic aberration of light with wavelengths of 656 nm, 610 nm, 555 nm, 510 nm, 470 nm, and 435 nm, respectively, after passing through the imaging optical lens 10 according to the first embodiment. Fig. 4 is a diagram showing field curvature and distortion aberration of light with 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 meridional direction.

[0070] In this embodiment, the imaging optical lens 10 has an entrance pupil diameter ENPD of 0.897 mm, an image height IH of the entire field of view of 2.693 mm, and a diagonal angle of view FOV of 111.80°. The imaging optical lens 10 satisfies the design requirements for a large aperture, extremely thin, and wide angle, and has excellent optical characteristics with its on-axis and off-axis chromatic aberrations sufficiently corrected. Second embodiment

[0071] In the second embodiment, the meanings of the symbols are the same as in the first embodiment.

[0072] Shown in FIG. 5 is an imaging optical lens 20 according to a second embodiment of the present invention.

[0073] Tables 5 and 6 show setting data of the imaging optical lens 20 according to the second embodiment of the present invention.

[0074] [Table 5]

[0075] Table 6 shows data on the aspheric surfaces of each lens in the imaging optical lens 20 according to the second embodiment of the present invention.

[0076] [Table 6]

[0077] Tables 7 and 8 show setting data for the inflection points and stationary points of each lens in the imaging optical lens 20 according to the second embodiment of the present invention.

[0078] [Table 7]

[0079] [Table 8]

[0080] Fig. 6 and Fig. 7 are diagrams showing spherical aberration and lateral chromatic aberration of light having wavelengths of 656 nm, 610 nm, 555 nm, 510 nm, 470 nm, and 435 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 having a wavelength of 555 nm after passing 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 meridional direction.

[0081] In this embodiment, the imaging optical lens 20 has an entrance pupil diameter ENPD of 0.884 mm, an image height IH of the entire field of view of 2.693 mm, and a diagonal angle of view FOV of 109.60°. The imaging optical lens 20 can satisfy the design requirements for a large aperture, extremely thin, and wide angle, and has excellent optical characteristics with its on-axis and off-axis chromatic aberrations sufficiently corrected. Third embodiment

[0082] In the third embodiment, the meanings of the symbols are the same as in the first embodiment.

[0083] Shown in FIG. 9 is an imaging optical lens 30 according to a third embodiment of the present invention.

[0084] Tables 9 and 10 show setting data for the imaging optical lens 30 according to the third embodiment of the present invention.

[0085] [Table 9]

[0086] Table 10 shows data on the aspheric surfaces of each lens in the imaging optical lens 30 according to the third embodiment of the present invention.

[0087] [Table 10]

[0088] Tables 11 and 12 show setting data for the inflection points and stationary points of each lens in the imaging optical lens 30 according to the third embodiment of the present invention.

[0089] [Table 11]

[0090] [Table 12]

[0091] Fig. 10 and Fig. 11 are diagrams showing spherical aberration and lateral chromatic aberration of light having wavelengths of 656 nm, 610 nm, 555 nm, 510 nm, 470 nm, and 435 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 having a wavelength of 555 nm after passing 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 meridional direction.

[0092] In this embodiment, the entrance pupil diameter ENPD of the imaging optical lens 30 is 0.890 mm, the image height IH of the entire field of view is 2.693 mm, and the diagonal angle of view FOV is 109.46°. The imaging optical lens 30 can satisfy the design requirements for a large aperture, extremely thin, and wide angle, and has excellent optical characteristics with its on-axis and off-axis chromatic aberrations sufficiently corrected. (Fourth embodiment)

[0093] In the fourth embodiment, the meanings of the symbols are the same as in the first embodiment.

[0094] Shown in FIG. 13 is an imaging optical lens 40 according to a fourth embodiment of the present invention.

[0095] Tables 13 and 14 show setting data for the imaging optical lens 40 according to the fourth embodiment of the present invention.

[0096] [Table 13]

[0097] Table 14 shows data on the aspheric surfaces of each lens in the imaging optical lens 40 according to the fourth embodiment of the present invention.

[0098] [Table 14]

[0099] Tables 15 and 16 show setting data for the inflection points and stationary points of each lens in the imaging optical lens 40 according to the fourth embodiment of the present invention.

[0100] [Table 15]

[0101] [Table 16]

[0102] Fig. 14 and Fig. 15 are diagrams showing spherical aberration and lateral chromatic aberration of light having wavelengths of 656 nm, 610 nm, 555 nm, 510 nm, 470 nm, and 435 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 having a wavelength of 555 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.

[0103] In this embodiment, the entrance pupil diameter ENPD of the imaging optical lens 40 is 0.887 mm, the image height IH of the entire field of view is 2.693 mm, and the diagonal angle of view FOV is 109.47°. The imaging optical lens 40 satisfies the design requirements of a large aperture, ultra-thinness, and ultra-wide angle, and has excellent optical characteristics with its on-axis and off-axis chromatic aberrations sufficiently corrected.

[0104] Table 21 below shows the values ​​of the first, second, third and fourth embodiments and the values ​​corresponding to the parameters defined in the relational expressions. (Comparative embodiment)

[0105] In the comparative embodiment, the symbols have the same meanings as in the first embodiment.

[0106] Shown in FIG. 17 is an imaging optical lens 50 according to a comparative embodiment.

[0107] Tables 17 and 18 show setting data of the imaging optical lens 50 according to the comparative embodiment.

[0108] [Table 17]

[0109] Table 18 shows data on the aspheric surfaces of each lens in the imaging optical lens 50 according to the comparative embodiment.

[0110] [Table 18]

[0111] 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 comparative embodiment.

[0112] [Table 19]

[0113] [Table 20]

[0114] Fig. 18 and Fig. 19 are diagrams showing spherical aberration and lateral chromatic aberration of light having wavelengths of 656 nm, 610 nm, 555 nm, 510 nm, 470 nm, and 435 nm, respectively, after passing through the imaging optical lens 50 according to the comparative embodiment. Fig. 20 is a diagram showing field curvature and distortion aberration of light having a wavelength of 555 nm after passing through the imaging optical lens 50 according to the comparative embodiment. The field curvature S in Fig. 20 is the field curvature in the sagittal direction, and T is the field curvature in the meridional direction.

[0115] Below, for each of the above relational expressions, the numerical values ​​corresponding to each relational expression in the comparative embodiment are shown in Table 21. Clearly, the imaging optical lens 50 of the comparative embodiment does not satisfy the above-mentioned relational expression 2.50≦f2 / f3≦7.00.

[0116] In the comparative embodiment, the entrance pupil diameter ENPD of the imaging optical lens 50 is 0.896 mm, the image height IH of the full field of view is 2.693 mm, and the diagonal angle of view FOV is 114.39°. The imaging optical lens 50 does not satisfy the design requirement for a wide angle.

[0117] [Table 21]

[0118] Although the above-mentioned embodiments are specific embodiments for realizing the present invention, it should be understood by those skilled in the art that in practical application, various changes in form and details that do not deviate from the spirit and scope of the present invention are all 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 positive refractive power, a third lens having positive refractive power, a fourth lens having negative refractive power, a fifth lens having positive refractive power, and a sixth lens having negative refractive power, Here, when a central radius of curvature of the object-side surface of the first lens is R1, a central radius of curvature of the image-side surface of the first lens is R2, 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, an axial thickness of the third lens is d5, an axial thickness of the fourth lens is d7, and an axial thickness of the fifth lens is d9, the imaging optical lens satisfies the following relational expression: 6.00≦R2 / R1≦25.00 2.00≦(R7+R8) / (R7-R8)≦9.00 3.00≦(d5+d9) / d7≦9.00

2. 2. The imaging optical lens according to claim 1, wherein the following relational expression is satisfied when the total optical length of the imaging optical lens is TTL and the focal length of the imaging optical lens is f: 2.00≦TTL / f≦2.30

3. 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 on-axis thickness of the sixth lens is d11: -6.00≦f6 / d11≦-3.00

4. 2. The imaging optical lens according to claim 1, wherein when a focal length of the second lens is f2 and a focal length of the third lens is f3, the following relational expression is satisfied: 2.50≦f2 / f3≦7.00

5. the first lens has an object-side surface formed as a concave surface on a paraxial line and an image-side surface formed as a convex surface on a paraxial line, 2. The imaging optical lens according to claim 1, wherein the following relational expression is satisfied when a focal length of the first lens is f1, a focal length of the imaging optical lens is f, an axial thickness of the first lens is d1, and a total optical length of the imaging optical lens is TTL: −5.26≦f1 / f≦−1.23 -2.80≦(R1+R2) / (R1-R2)≦-0.72 0.02≦d1 / TTL≦0.06

6. the second lens has an object-side surface formed as a convex surface on a paraxial line and an image-side surface formed as a concave surface on a paraxial line, 2. The imaging optical lens according to claim 1, wherein the following relational expression is satisfied when a focal length of the second lens is f2, a focal length of the imaging optical lens is f, 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: 1.50≦f2 / f≦11.95 -54.86≦(R3+R4) / (R3-R4)≦-4.92 0.03≦d3 / TTL≦0.11

7. the third lens has an object-side surface formed as a convex surface on a paraxial line, and an image-side surface formed as a convex surface on a paraxial line, 2. The imaging optical lens according to claim 1, wherein the following relational expression is satisfied when a focal length of the third lens is f3, a focal length of the imaging optical lens is f, 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 a total optical length of the imaging optical lens is TTL: 0.57≦f3 / f≦1.79 0.11≦(R5+R6) / (R5-R6)≦0.37 0.06≦d5 / TTL≦0.18

8. the fourth lens has an object-side surface formed as a convex surface on a paraxial line and an image-side surface formed as a concave surface on a paraxial line, 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 focal length of the imaging optical lens is f, and a total optical length of the imaging optical lens is TTL: −9.47≦f4 / f≦−2.92 0.03≦d7 / TTL≦0.09

9. the fifth lens has an object-side surface formed as a concave 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 fifth lens is f5, a focal length of the imaging optical lens is f, a central radius of curvature of an object-side surface of the fifth lens is R9, a central radius of curvature of an image-side surface of the fifth lens is R10, and a total optical length of the imaging optical lens is TTL: 0.29≦f5 / f≦0.89 0.83≦(R9+R10) / (R9-R10)≦2.60 0.09≦d9 / TTL≦0.26

10. the sixth lens has an object-side surface formed as a convex surface on a paraxial line and an image-side surface formed as a concave surface on a paraxial line, 2. The imaging optical lens according to claim 1, wherein the following relational expression is satisfied when a focal length of the sixth lens is f6, a focal length of the imaging optical lens is f, a central radius of curvature of an object-side surface of the sixth lens is R11, a central radius of curvature of an image-side surface of the sixth lens is R12, an axial thickness of the sixth lens is d11, and a total optical length of the imaging optical lens is TTL: −1.44≦f6 / f≦−0.48 0.89≦(R11+R12) / (R11-R12)≦2.74 0.04≦d11 / TTL≦0.13

Images