JP2020027261A - Image capturing optical lens - Google Patents

Abstract

To provide an optical lens, in particular an image capturing optical lens.SOLUTION: An image capturing optical lens comprises, in order from an object side to an image side, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens, the first lens being made of glass, the second lens plastic, the third lens plastic, the fourth lens plastic, the fifth lens plastic, and the sixth lens plastic. The second lens has positive refractive power and the third lens has positive refractive power. The image capturing optical lens satisfies the following conditional expressions: -3≤f1/f≤-1.5, 1.7≤n1≤2.2, 0.9≤f5/f6≤2. The image capturing optical lens offers high imaging performance and a short total optical length (TTL).SELECTED DRAWING: Figure 1

Description

  The present invention relates to the field of optical lenses, and more particularly, to an imaging optical lens applied to a mobile terminal device such as a smartphone and a digital camera and an imaging device such as a monitor and a PC lens.

  In recent years, with the advent of smartphones, the demand for small imaging lenses has been increasing more and more. Generally, the photosensitive elements of the imaging lenses are generally photosensitive coupled devices (Charge Coupled Devices, CCDs) or complementary metal oxide semiconductors. It is roughly classified into only two types of elements (Complementary Metal-Oxide Semiconductor Sensor, CMOS Sensor). In addition, with advances in semiconductor manufacturing technology, the pixel size of the photosensitive element can be reduced, and current electronic products tend to develop excellent functions and lighter, thinner, and smaller appearances. For this reason, small-sized imaging lenses having good imaging quality are already mainstream in the current market. In order to obtain excellent image quality, a conventional lens mounted on a camera of a mobile phone often uses a three-lens or four-lens structure. In addition, when the pixel area of the photosensitive element is decreasing and the demand from the system for the imaging quality is increasing with the development of technology and the increasing needs of diversification of users, a five-sheet type Six-lens and seven-lens lens structures are gradually appearing in the lens design. The demand for a wide-angle imaging lens having excellent optical characteristics, ultra-thinness and sufficient correction of chromatic aberration has been tightened.

  The present invention has been made in view of the above-described problems, and has as its object to provide an imaging optical lens that achieves high imaging performance and satisfies the demand for extremely thin and wide-angle lenses.

In order to solve the above problems, embodiments of the present invention provide an imaging optical lens. The imaging optical lens includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens in order from the object side to the image side, and the second lens has a positive refractive power. Wherein the third lens has a positive refractive power;
The focal length of the imaging optical lens is f, the focal length of the first lens is f1, the refractive index of the first lens is n1, the focal length of the fifth lens is f5, and the focal length of the sixth lens is f6. Then, the following conditional expressions (1) to (3) are satisfied.
-3≤f1 / f≤-1.5 (1)
1.7 ≦ n1 ≦ 2.2 (2)
0.9 ≦ f5 / f6 ≦ 2 (3)

  The embodiment of the present invention has a specific relationship with respect to the prior art based on the data of the focal length, the refractive index, the optical length of the imaging optical lens, the axial thickness, and the radius of curvature based on the above-described lens arrangement method. By the cooperation of the lenses, the imaging optical lens can obtain a high imaging performance, and can satisfy the demand for ultra-thin and wide-angle.

  Preferably, the first lens is a glass material, the second lens is a plastic material, the third lens is a plastic material, the fourth lens is a plastic material, and the fifth lens is a plastic material. Wherein the sixth lens is made of a plastic material.

Preferably, the imaging optical lens satisfies the following conditional expressions (4) to (6).
-2.781≤f1 / f≤-1.974 (4)
1.797 ≦ n1 ≦ 2.08 (5)
0.903 ≦ f5 / f6 ≦ 1.505 (6)

Preferably, the first lens has a negative refractive power, the object side surface is convex on the paraxial side, the image side surface is concave on the paraxial side, and the radius of curvature of the object side surface of the first lens is When R1, the 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 optical length of the imaging optical lens is TTL, the following conditional expressions (7) to (8) Meet).
3.92 ≦ (R1 + R2) / (R1−R2) ≦ 11.97 (7)
0.02 ≦ d1 / TTL ≦ 0.07 (8)

Preferably, the imaging optical lens satisfies the following conditional expressions (9) to (10).
6.27 ≦ (R1 + R2) / (R1−R2) ≦ 9.58 (9)
0.04 ≦ d1 / TTL ≦ 0.06 (10)

Preferably, in the second lens, the object side surface is a convex surface in a paraxial direction, the image side surface is a concave surface in a paraxial direction, the focal length of the second lens is f2, and the radius of curvature of the object side surface of the second lens is When R3 is R4, the 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 optical length of the imaging optical lens is TTL, the following conditional expressions (11) to (13) Meet).
0.42 ≦ f2 / f ≦ 1.28 (11)
-3.44≤ (R3 + R4) / (R3-R4) ≤-1.12 (12)
0.05 ≦ d3 / TTL ≦ 0.16 (13)

Preferably, the imaging optical lens satisfies the following conditional expressions (14) to (16).
0.67 ≦ f2 / f ≦ 1.02 (14)
−2.15 ≦ (R3 + R4) / (R3-R4) ≦ −1.40 (15)
0.08 ≦ d3 / TTL ≦ 0.13 (16)

The third lens has an object side surface that is convex on a paraxial side, an image side surface that is concave on a paraxial side,
Preferably, the focal length of the third lens is f3, the radius of curvature of the object side surface of the third lens is R5, the radius of curvature of the image side surface of the third lens is R6, the on-axis thickness of the third lens is d5, When the optical length of the imaging optical lens is TTL, the following conditional expressions (17) to (19) are satisfied.
34.167 ≦ f3 / f ≦ 171.011 (17)
29.23 ≦ (R5 + R6) / (R5-R6) ≦ 115.24 (18)
0.03 ≦ d5 / TTL ≦ 0.08 (19)

Preferably, the imaging optical lens satisfies the following conditional expressions (20) to (22).
54.668 ≦ f3 / f ≦ 136.809 (20)
46.77 ≦ (R5 + R6) / (R5-R6) ≦ 92.19 (21)
0.04 ≦ d5 / TTL ≦ 0.07 (22)

Preferably, the fourth lens has a positive refractive power, the object side surface is concave on the paraxial side, the image side surface is convex on the paraxial side, and the focal length of the fourth lens is f4. When the radius of curvature of the object side surface of the fourth lens is R7, the radius of curvature of the image side surface of the fourth lens is R8, the on-axis thickness of the fourth lens is d7, and the optical length of the imaging optical lens is TTL, The following conditional expressions (23) to (25) are satisfied.
0.80 ≦ f4 / f ≦ 2.43 (23)
0.96 ≦ (R7 + R8) / (R7−R8) ≦ 2.93 (24)
0.05 ≦ d7 / TTL ≦ 0.16 (25)

Preferably, the imaging optical lens satisfies the following conditional expressions (26) to (28).
1.28 ≦ f4 / f ≦ 1.94 (26)
1.53 ≦ (R7 + R8) / (R7−R8) ≦ 2.35 (27)
0.08 ≦ d7 / TTL ≦ 0.13 (28)

Preferably, the fifth lens has a negative refractive power, the object side surface is concave on the paraxial side, the image side surface is convex on the paraxial side, and the focal length of the fifth lens is f5, When the radius of curvature of the object side surface of the fifth lens is R9, the radius of curvature of the image side surface of the fifth lens is R10, the on-axis thickness of the fifth lens is d9, and the optical length of the imaging optical lens is TTL, The following conditional expressions (29) to (31) are satisfied.
−8.84 ≦ f5 / f ≦ −2.76 (29)
−20.44 ≦ (R9 + R10) / (R9−R10) ≦ −6.55 (30)
0.03 ≦ d9 / TTL ≦ 0.08 (31)

Preferably, the imaging optical lens satisfies the following conditional expressions (32) to (34).
−5.52 ≦ f5 / f ≦ −3.45 (32)
−12.77 ≦ (R9 + R10) / (R9−R10) ≦ −8.18 (33)
0.04 ≦ d9 / TTL ≦ 0.07 (34)

Preferably, the sixth lens has a negative refractive power, the object side surface is a convex surface on the paraxial side, the image side surface is a concave surface on the paraxial side, and the focal length of the sixth lens is f6. When the radius of curvature of the object side surface of the sixth lens is R11, the radius of curvature of the image side surface of the sixth lens is R12, the on-axis thickness of the sixth lens is d11, and the optical length of the imaging optical lens is TTL, The following conditional expressions (35) to (37) are satisfied.
−9.16 ≦ f6 / f ≦ −2.92 (35)
2.68 ≦ (R11 + R12) / (R11−R12) ≦ 8.21 (36)
0.09 ≦ d11 / TTL ≦ 0.28 (37)

Preferably, the imaging optical lens satisfies the following conditional expressions (38) to (40).
−5.72 ≦ f6 / f ≦ −3.65 (38)
4.29 ≦ (R11 + R12) / (R11−R12) ≦ 6.57 (39)
0.15 ≦ d11 / TTL ≦ 0.22 (40)

Preferably, when the combined focal length of the first lens and the second lens is f12, the following conditional expression (41) is satisfied.
0.70 ≦ f12 / f ≦ 2.14 (41)

Preferably, the imaging optical lens satisfies the following conditional expression (42).
1.13 ≦ f12 / f ≦ 1.71 (42)

  Preferably, the optical length TTL of the imaging optical lens is 5.18 mm or less.

  Preferably, the optical length TTL of the imaging optical lens is 4.94 mm or less.

  Preferably, the aperture F value of the imaging optical lens is 2.27 or less.

  Preferably, the aperture F value of the imaging optical lens is 2.22 or less.

  The present invention has the following advantageous effects. The imaging optical lens according to the present invention has excellent optical characteristics, is extremely thin, has a wide angle, and is sufficiently corrected for chromatic aberration. The present invention can be applied to an imaging lens unit and a WEB imaging lens.

FIG. 1 is a schematic diagram illustrating a structure of an imaging optical lens according to a first embodiment of the present invention. FIG. 2 is a schematic diagram illustrating axial chromatic aberration of the imaging optical lens illustrated in FIG. 1. FIG. 2 is a schematic diagram illustrating chromatic aberration of magnification of the imaging optical lens illustrated in FIG. 1. FIG. 2 is a schematic diagram illustrating curvature of field and distortion of the imaging optical lens illustrated in FIG. 1. It is a schematic diagram showing the structure of the imaging optical lens according to the second embodiment of the present invention. FIG. 6 is a schematic diagram illustrating axial chromatic aberration of the imaging optical lens illustrated in FIG. 5. FIG. 6 is a schematic diagram illustrating chromatic aberration of magnification of the imaging optical lens illustrated in FIG. 5. FIG. 6 is a schematic diagram illustrating field curvature and distortion of the imaging optical lens illustrated in FIG. 5. It is a schematic diagram showing the structure of the imaging optical lens of the third embodiment of the present invention. FIG. 10 is a schematic diagram illustrating axial chromatic aberration of the imaging optical lens illustrated in FIG. 9. FIG. 10 is a schematic diagram illustrating chromatic aberration of magnification of the imaging optical lens illustrated in FIG. 9. FIG. 10 is a schematic diagram illustrating field curvature and distortion of the imaging optical lens illustrated in FIG. 9.

  Embodiments of the present invention will be described below in detail with reference to the drawings so that the objects, solutions, and merits of the present invention become clearer. However, in each embodiment of the present invention, although many technical details are given so that the present invention may be better understood, various changes and modifications based on those technical details and the following embodiments may be performed. It should be understood by those skilled in the art that the protection sought of the present invention may be practiced, even if not present.

(1st Embodiment)
Referring to the drawings, the present invention provides an imaging optical lens 10. FIG. 1 shows an imaging optical lens 10 according to a first embodiment of the present invention. The imaging optical lens 10 includes six lenses. Specifically, the imaging optical lens 10 sequentially includes an aperture S1, a first lens L1, a second lens L2, a third lens L3, a fourth lens L4, a fifth lens L5, and It consists of a sixth lens L6. An optical element such as an optical filter (filter) GF may be provided between the sixth lens L6 and the image plane Si.

  Here, the first lens L1 is a glass material, the second lens L2 is a plastic material, the third lens L3 is a plastic material, the fourth lens L4 is a plastic material, and the fifth lens L5 is a plastic material. And the sixth lens L6 is made of a plastic material. The second lens L2 has a positive refractive power, and the third lens L3 has a positive refractive power.

Here, the focal length of the entire imaging optical lens 10 is defined as f, and the focal length of the first lens L1 is defined as f1.
Conditional expression-3 ≦ f1 / f ≦ −1.5 defines the negative refractive power of the first lens L1. Exceeding the upper limit value is advantageous for making the lens extremely thin. However, the negative refractive power of the first lens L1 becomes too strong, making it difficult to correct aberrations and disadvantageous for widening the lens angle. become. Conversely, when the value falls below the lower limit, the negative refractive power of the first lens becomes too weak, and it becomes difficult to make the lens extremely thin. Preferably, conditional expression -2.781 ≦ f1 / f ≦ −1.974 is satisfied.

  The refractive index of the first lens L1 is defined as n1. Conditional expression 1.7 ≦ n1 ≦ 2.2 defines the refractive index of the first lens L1. Setting within this range is more advantageous for making the lens extremely thin, and also advantageous for correcting aberrations. Preferably, conditional expression 1.797 ≦ n1 ≦ 2.08 is satisfied.

  The focal length f5 of the fifth lens and the focal length f6 of the sixth lens satisfy 0.9 ≦ f5 / f6 ≦ 2, and define the ratio of the focal length f5 of the fifth lens to the focal length f6 of the sixth lens. However, it is advantageous in achieving ultra-thinness. Preferably, 0.903 ≦ f5 / f6 ≦ 1.505 is satisfied.

  When the focal length of the imaging optical lens 10 of the present invention, the focal length of each lens, the refractive index of the related lens, the optical length of the imaging optical lens, the axial thickness, and the radius of curvature satisfy the above conditional expressions, 10 has high performance and satisfies low TTL design demands.

  In the present embodiment, the first lens L1 has an object side surface that is convex on the paraxial side, an image side surface that is concave on the paraxial side, and has a negative refractive power.

  If the radius of curvature of the object side surface of the first lens L1 is defined as R1, and the radius of curvature of the image side surface of the first lens L1 is defined as R2, the conditional expression 3.92 ≦ (R1 + R2) / (R1-R2) ≦ 11.97 is satisfied. . By reasonably defining the shape of the first lens, the first lens can effectively correct the spherical aberration of the system. Preferably, the conditional expression 6.27 ≦ (R1 + R2) / (R1−R2) ≦ 9.58 is satisfied.

  The on-axis thickness d1 of the first lens L1 and the optical length TTL of the imaging optical lens 10 satisfy the following conditional expressions. That is, the conditional expression 0.02 ≦ d1 / TTL ≦ 0.07 is satisfied. This is advantageous for achieving a very thin thickness. Preferably, the conditional expression 0.04 ≦ d1 / TTL ≦ 0.06 is satisfied.

  In the present embodiment, the second lens L2 has a convex surface on the object side surface, a concave surface on the image side, and a positive refractive power.

  The focal length f of the entire imaging optical lens 10 and the focal length f2 of the second lens L2 satisfy the following conditional expression. That is, by satisfying the conditional expression 0.42 ≦ f2 / f ≦ 1.28, and defining the positive refractive power of the second lens L2 in a reasonable range, the spherical surface generated by the first lens L1 having a negative refractive power. The balance between the aberration and the amount of curvature of field of the system is rationally and effectively balanced. Preferably, the conditional expression 0.67 ≦ f2 / f ≦ 1.02 is satisfied.

  The radius of curvature of the object side surface of the second lens is defined as R3, and the radius of curvature of the image side surface of the second lens is defined as R4. The conditional expression -3.44≤ (R3 + R4) / (R3-R4) ≤-1.12 is satisfied, thereby defining the shape of the second lens L2. Outside this range, it becomes difficult to correct axial chromatic aberration as the lens becomes thinner and wider. Preferably, the conditional expression -2.15 ≦ (R3 + R4) / (R3-R4) ≦ −1.40 is satisfied.

  The on-axis thickness d3 of the second lens L2 satisfies the conditional expression 0.05 ≦ d3 / TTL ≦ 0.16, which is advantageous for achieving an extremely thin thickness. Preferably, the conditional expression 0.08 ≦ d3 / TTL ≦ 0.13 is satisfied.

In the present embodiment, the third lens L3 has an object side surface that is convex on the paraxial side, an image side surface that is concave on the paraxial side, and has a positive refractive power.
The focal length f of the entire imaging optical lens 10 and the focal length f3 of the third lens L3 satisfy the following conditional expression. That is, the conditional expression 34.167 ≦ f3 / f ≦ 171.011 is satisfied. This is advantageous in obtaining the ability to balance the field curvature well in the system, and effectively improves imaging quality. Preferably, the conditional expression 54.668 ≦ f3 / f ≦ 136.809 is satisfied.

  The radius of curvature R5 of the object side surface of the third lens and the radius of curvature R6 of the image side surface of the third lens satisfy the conditional expression 29.23 ≦ (R5 + R6) / (R5-R6) ≦ 115.24. The shape of the lens L3 is effectively defined, which is advantageous for molding the third lens L3, and avoids molding failure and generation of stress due to too large a curvature of the surface of the third lens L3. Preferably, the conditional expression 46.77 ≦ (R5 + R6) / (R5-R6) ≦ 92.19 is satisfied.

  The axial thickness d5 of the third lens L3 satisfies the conditional expression 0.03 ≦ d5 / TTL ≦ 0.08, which is advantageous for achieving an extremely thin thickness. Preferably, the conditional expression 0.04 ≦ d5 / TTL ≦ 0.07 is satisfied.

  In the present embodiment, the fourth lens L4 has a concave surface on the object side, a convex surface on the image side, and a positive refractive power.

  The focal length f of the entire imaging optical lens 10 and the focal length f4 of the fourth lens L4 satisfy the following conditional expression. That is, the conditional expression 0.80 ≦ f4 / f ≦ 2.43 is satisfied. Due to the reasonable distribution of refractive power, the system has excellent imaging quality and low sensitivity. Preferably, the conditional expression 1.28 ≦ f4 / f ≦ 1.94 is satisfied.

  The radius of curvature R7 of the object side surface of the fourth lens L4 and the radius of curvature R8 of the image side surface of the fourth lens L4 satisfy the conditional expression 0.96 ≦ (R7 + R8) / (R7−R8) ≦ 2.93, and the fourth lens This defines the shape of L4. Outside this range, it becomes difficult to correct the aberration of the off-axis angle of view as the lens becomes thinner and wider. Preferably, the conditional expression 1.53 ≦ (R7 + R8) / (R7−R8) ≦ 2.35 is satisfied.

  The on-axis thickness d7 of the fourth lens L4 satisfies the conditional expression 0.05 ≦ d7 / TTL ≦ 0.16, which is advantageous for achieving an extremely thin thickness. Preferably, the conditional expression 0.08 ≦ d7 / TTL ≦ 0.13 is satisfied.

  In the present embodiment, the fifth lens L5 has an object side surface that is concave on the paraxial side, an image side surface that is convex on the paraxial side, and has a negative refractive power.

  The focal length f of the entire imaging optical lens 10 and the focal length f5 of the fifth lens L5 satisfy the following conditional expression. That is, limiting the fifth lens L5 with the conditional expression −8.84 ≦ f5 / f ≦ −2.76 can effectively reduce the light beam angle of the imaging lens and reduce the tolerance sensitivity. Preferably, conditional expression -5.52 ≦ f5 / f ≦ −3.45 is satisfied.

  The radius of curvature R9 of the object side surface of the fifth lens L5 and the radius of curvature R10 of the image side surface of the fifth lens L5 satisfy conditional expression-20.44 ≦ (R9 + R10) / (R9−R10) ≦ −6.55. This defines the shape of the five lenses L5. Outside this range, it becomes difficult to correct the aberration of the off-axis angle of view as the lens becomes thinner and wider. Preferably, the conditional expression −12.77 ≦ (R9 + R10) / (R9−R10) ≦ −8.18 is satisfied.

  The axial thickness d9 of the fifth lens L5 satisfies the conditional expression 0.03 ≦ d9 / TTL ≦ 0.08, which is advantageous for achieving an extremely thin thickness. Preferably, the conditional expression 0.04 ≦ d9 / TTL ≦ 0.07 is satisfied.

  In the present embodiment, the sixth lens L6 has a convex surface on the object side, a concave surface on the image side, and a negative refractive power.

  The focal length f of the imaging optical lens 10 and the focal length f6 of the sixth lens L6 satisfy the following conditional expression. That is, the conditional expression −9.16 ≦ f6 / f ≦ −2.92 is satisfied. Due to the reasonable distribution of refractive power, the system has excellent imaging quality and low sensitivity. Preferably, conditional expression -5.72 ≦ f6 / f ≦ −3.65 is satisfied.

  The radius of curvature R11 of the object side surface of the sixth lens L6 and the radius of curvature R12 of the image side surface of the sixth lens L6 satisfy conditional expression 2.68 ≦ (R11 + R12) / (R11−R12) ≦ 8.21. This defines the shape of L6. Outside this range, it becomes difficult to correct the aberration of the off-axis angle of view as the lens becomes extremely thin and wide. Preferably, the conditional expression 4.29 ≦ (R11 + R12) / (R11−R12) ≦ 6.57 is satisfied.

  The axial thickness d11 of the sixth lens L6 satisfies the conditional expression 0.09 ≦ d11 / TTL ≦ 0.28, which is advantageous for achieving an extremely thin thickness. Preferably, the conditional expression 0.15 ≦ d11 / TTL ≦ 0.22 is satisfied.

  In this embodiment, the combined focal length f12 between the first lens and the second lens satisfies the conditional expression 0.70 ≦ f12 / f ≦ 2.14. As a result, the field curvature and distortion of the imaging optical lens can be eliminated, the back focus of the imaging optical lens can be suppressed, and downsizing of the image lens system group can be maintained. Preferably, the conditional expression 1.13 ≦ f12 / f ≦ 1.71 is satisfied.

  In the present embodiment, the optical length TTL of the imaging optical lens 10 is equal to or less than 5.18 mm, which is advantageous for achieving extremely thinness. Preferably, the optical length TTL of the imaging optical lens 10 is 4.94 mm or less.

  In the present embodiment, the imaging optical lens 10 has a large aperture, and the aperture F value is 2.27 or less, and is excellent in imaging performance. Preferably, the aperture F value of the imaging optical lens 10 is 2.22 or less.

  With this design, the optical length TTL of the entire imaging optical lens 10 can be made as short as possible, and the characteristics of miniaturization can be maintained.

  Hereinafter, the imaging optical lens 10 according to the present invention will be described using examples. The reference numerals described in each embodiment are as follows.

The units of the focal length, the axial distance, the radius of curvature, the axial thickness, the inflection point position and the stop point position are mm.
TTL is the optical length (axial distance from the object side surface of the first lens L1 to the image plane), and the unit is mm.

  Preferably, an inflection point and / or a stationary point may be provided on an object side and / or an image side of the lens so as to satisfy a demand for high quality imaging. See the description below for specific implementation plans.

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

Here, the meaning of each code is as follows,
S1: stop R: radius of curvature of the optical surface, in the case of a lens, center radius of curvature R1: radius of curvature of the object side surface of the first lens L1 R2: radius of curvature of the image side surface of the first lens L1
R3: radius of curvature of the object side surface of the second lens L2 R4: radius of curvature of the image side surface of the second lens L2 R5: radius of curvature of the object side surface of the third lens L3 R6: radius of curvature of the image side surface of the third lens L3 R7: Radius of curvature of the object side surface of the fourth lens L4 R8: Radius of curvature of the image side surface of the fourth lens L4 R9: Radius of curvature of the object side surface of the fifth lens L5 R10: Radius of curvature of the image side surface of the fifth lens L5 R11: Sixth Radius of curvature of the object side surface of the lens L6 R12: Curvature radius of the image side surface of the sixth lens L6 R13: Radius of curvature of the object side surface of the optical filter GF R14: Radius of curvature of the image side surface of the optical filter GF d: On-axis thickness of the lens Or, the on-axis distance between the lenses d0: the on-axis distance from the stop S1 to the object side surface of the first lens L1 d1: the on-axis thickness of the first lens L1 d2: from the image side surface of the first lens L1 The axial distance d2 of the second lens L2 to the object side surface d3: the axial thickness of the second lens L2 d4: the axial distance from the image side surface of the second lens L2 to the object side surface of the third lens L3 d5: the axial distance of the third lens L3 Axial thickness d6: axial distance from the image side surface of third lens L3 to the object side surface of fourth lens L4 d7: axial thickness of fourth lens L4 d8: distance of fifth lens L5 from the image side surface of fourth lens L4 On-axis distance to object side surface d9: On-axis thickness of fifth lens L5 d10: On-axis distance from image side surface of fifth lens L5 to object side surface of sixth lens L6 d11: On-axis thickness of sixth lens L6 d12 : 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 the optical filter GF d14: axial distance from the image side surface of the optical filter GF to the image plane nd: d-line refraction Index nd1: Refractive index of d-line of first lens L1 nd2: Refractive index of d-line of second lens L2 nd3: Refractive index of d-line of third lens L3 nd4: Refractive index of d-line of fourth lens L4 nd5 : D-line refractive index of the fifth lens L5 nd6: d-line refractive index of the sixth lens L6 ndg: d-line refractive index of the optical filter GF vd: Abbe number v1: Abbe number of the first lens L1 v2: first Abbe number of second lens L2 v3: Abbe number of third lens L3 v4: Abbe number of fourth lens L4 v5: Abbe number of fifth lens L5 v6: Abbe number of sixth lens L6 vg: Abbe number of optical filter GF

  Table 2 shows aspherical data of each lens in the imaging optical lens 10 according to the first embodiment of the present invention.

Here, k is a cone coefficient, and A4, A6, A8, A10, A12, A14, and A16 are aspherical coefficients.
The IH: image height ^{y = (x 2 / R)} / [1+ {1- (k + 1) (x 2 / R 2)} 1/2]
^{+ A4x 4 + A6x 6 + A8x} 8 + A10x 10 + A12x 12 + A14x 14 + A16x 16 (43)

  As the aspheric surface of each lens surface, for convenience, an aspheric surface represented by the above equation (43) is used. However, the present invention is not particularly limited to the aspherical polynomial of this equation (43).

  Tables 3 and 4 show design data of the inflection point and the stop point 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 the image side surface of the first lens L1, P2R1 and P2R2 respectively indicate the object side surface and the image side surface of the second lens L2, and P3R1 and P3R2 respectively indicate the third lens. L3 indicates the object side and image side, P4R1 and P4R2 indicate the object side and image side of the fourth lens L4, respectively, and P5R1 and P5R2 indicate the object side and image side of the fifth lens L5, respectively. P6R2 indicates the object side surface and the image side surface of the sixth lens L6, respectively. The corresponding data in the “inflection point position” column is the vertical distance from the inflection point installed on the surface of each lens to the optical axis of the imaging optical lens 10. The corresponding data in the “stop point position” column is the vertical distance from the stop point installed on the surface of each lens to the optical axis of the imaging optical lens 10.

  FIGS. 2 and 3 are schematic diagrams showing axial chromatic aberration and lateral chromatic aberration after light having wavelengths of 470 nm, 555 nm, and 650 nm respectively has passed through the imaging optical lens 10 according to the first embodiment. FIG. 4 is a schematic diagram showing field curvature and distortion after light having a wavelength of 555 nm has passed through the imaging optical lens 10 according to the first embodiment. The field curvature S in FIG. T is the curvature of field in the meridional direction.

  Table 13 below shows various values of Examples 1, 2, and 3, and values corresponding to the parameters defined by the conditional expressions.

  As shown in Table 13, the first embodiment satisfies each conditional expression.

  In the present embodiment, the entrance pupil diameter of the imaging optical lens is 1.663 mm, the image height of the entire field of view is 2.933 mm, and the angle of view in the diagonal direction is 78.51 °, which is a wide angle and extremely thin. In addition, on-axis, off-axis chromatic aberration is sufficiently corrected and has excellent optical characteristics.

(2nd Embodiment)
The second embodiment is basically the same as the first embodiment, and the meanings of the reference numerals are the same as those of the first embodiment. Therefore, only different points will be described below.
FIG. 5 shows an imaging optical lens 20 according to the second embodiment of the present invention.

  Tables 5 and 6 show design data of the imaging optical lens 20 according to the second embodiment of the present invention.

  Table 6 shows aspherical data of each lens in the imaging optical lens 20 according to the second embodiment of the present invention.

  Tables 7 and 8 show design data of an inflection point and a stop point of each lens in the imaging optical lens 20 according to the second embodiment of the present invention.

  FIGS. 6 and 7 are schematic diagrams illustrating axial chromatic aberration and lateral chromatic aberration after light having wavelengths of 470 nm, 555 nm, and 650 nm, respectively, has passed through the imaging optical lens 20 according to the second embodiment. FIG. 8 is a schematic diagram illustrating field curvature and distortion after light having a wavelength of 555 nm has passed through the imaging optical lens 20 according to the second embodiment.

  As shown in Table 13, the second embodiment satisfies each conditional expression.

  In the present embodiment, the entrance pupil diameter of the imaging optical lens is 1.663 mm, the image height of the entire field of view is 2.933 mm, the angle of view in the diagonal direction is 78.51 °, and the wide angle and extremely thin In addition, on-axis, off-axis chromatic aberration is sufficiently corrected and has excellent optical characteristics.

(Third embodiment)
The third embodiment is basically the same as the first embodiment, and the meanings of the reference numerals are the same as those of the first embodiment. Therefore, only different points will be described below.
FIG. 9 shows an imaging optical lens 30 according to the third embodiment of the present invention.

  Tables 9 and 10 show design data of the imaging optical lens 30 according to the third embodiment of the present invention.

  Table 10 shows aspherical data of each lens in the imaging optical lens 30 according to the third embodiment of the present invention.

  Tables 11 and 12 show inflection point and stop point design data of each lens in the imaging optical lens 30 according to the third embodiment of the present invention.

  FIGS. 10 and 11 are schematic diagrams showing axial chromatic aberration and chromatic aberration of magnification after light having wavelengths of 470 nm, 555 nm, and 650 nm, respectively, has passed through the imaging optical lens 30 of the third embodiment. FIG. 12 is a schematic diagram illustrating a field curvature and a distortion after light having a wavelength of 555 nm passes through the imaging optical lens 30 of the third embodiment.

  In Table 13, numerical values corresponding to the conditional expressions in the present embodiment according to the above conditional expressions are listed. Obviously, the imaging optical system of the present embodiment satisfies the above conditional expression.

  In the present embodiment, the entrance pupil diameter of the imaging optical lens is 1.663 mm, the image height of the entire field of view is 2.933 mm, the angle of view in the diagonal direction is 78.47 °, and the wide angle and extremely thin In addition, on-axis, off-axis chromatic aberration is sufficiently corrected and has excellent optical characteristics.

  As will be understood by those skilled in the art, each of the above embodiments is a specific embodiment for realizing the present invention, and in actual application, various forms and details may be used without departing from the spirit and scope of the present invention. Is possible.

In order to solve the above problems, embodiments of the present invention provide an imaging optical lens. The imaging optical lens includes, in order from the object side to the image side, a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens, wherein the first lens has a negative refractive power. a, the second lens has a positive refractive power, the third lens has a positive refractive power, the fourth lens has a positive refractive power, the refractive said fifth lens is negative The sixth lens has a negative refractive power,
The focal length of the imaging optical lens is f, the focal length of the first lens is f1, the refractive index of the first lens is n1, the focal length of the fifth lens is f5, and the focal length of the sixth lens is f6. Then, the following conditional expressions (1) to (3) are satisfied.
-3≤f1 / f≤-1.5 (1)
1.7 ≦ n1 ≦ 2.2 (2)
0.9 ≦ f5 / f6 ≦ 2 (3)

Claims (21)

An imaging optical lens,
The first lens, the second lens, the third lens, the fourth lens, the fifth lens, and the sixth lens are arranged in order from the object side to the image side, and the second lens has a positive refractive power. The third lens has a positive refractive power,
The focal length of the imaging optical lens is f, the focal length of the first lens is f1, the refractive index of the first lens is n1, the focal length of the fifth lens is f5, and the focal length of the sixth lens is f6. An imaging optical lens satisfying the following conditional expressions (1) to (3).
-3≤f1 / f≤-1.5 (1)
1.7 ≦ n1 ≦ 2.2 (2)
0.9 ≦ f5 / f6 ≦ 2 (3)   The first lens is a glass material, the second lens is a plastic material, the third lens is a plastic material, the fourth lens is a plastic material, the fifth lens is a plastic material, The imaging optical lens according to claim 1, wherein the sixth lens is made of a plastic material. The imaging optical lens according to claim 1, wherein the following conditional expressions (4) to (6) are satisfied.
-2.781≤f1 / f≤-1.974 (4)
1.797 ≦ n1 ≦ 2.08 (5)
0.903 ≦ f5 / f6 ≦ 1.505 (6) The first lens has a negative refractive power, the object side surface is a convex surface in a paraxial direction, the image side surface is a concave surface in a paraxial direction,
When the radius of curvature of the object side surface of the first lens is R1, the radius of curvature of the image side surface of the first lens is R2, the on-axis thickness of the first lens is d1, and the optical length of the imaging optical lens is TTL. 2. The imaging optical lens according to claim 1, wherein the following conditional expressions (7) to (8) are satisfied.
3.92 ≦ (R1 + R2) / (R1−R2) ≦ 11.97 (7)
0.02 ≦ d1 / TTL ≦ 0.07 (8) The imaging optical lens according to claim 4, wherein the following conditional expressions (9) to (10) are satisfied.
6.27 ≦ (R1 + R2) / (R1−R2) ≦ 9.58 (9)
0.04 ≦ d1 / TTL ≦ 0.06 (10) The second lens has an object side surface that is convex on a paraxial side, an image side surface that is concave on a paraxial side,
The focal length of the second lens is f2, the radius of curvature of the object side surface of the second lens is R3, the radius of curvature of the image side surface of the second lens is R4, the on-axis thickness of the second lens is d3, and the imaging optics is The imaging optical lens according to claim 1, wherein the following conditional expressions (11) to (13) are satisfied when the optical length of the lens is TTL.
0.42 ≦ f2 / f ≦ 1.28 (11)
-3.44≤ (R3 + R4) / (R3-R4) ≤-1.12 (12)
0.05 ≦ d3 / TTL ≦ 0.16 (13) The imaging optical lens according to claim 6, wherein the following conditional expressions (14) to (16) are satisfied.
0.67 ≦ f2 / f ≦ 1.02 (14)
−2.15 ≦ (R3 + R4) / (R3-R4) ≦ −1.40 (15)
0.08 ≦ d3 / TTL ≦ 0.13 (16) The third lens has an object side surface that is convex on a paraxial side, an image side surface that is concave on a paraxial side,
The focal length of the third lens is f3, the radius of curvature of the object side surface of the third lens is R5, the radius of curvature of the image side surface of the third lens is R6, the axial thickness of the third lens is d5, and the imaging optics is The imaging optical lens according to claim 1, wherein the following conditional expressions (17) to (19) are satisfied when the optical length of the lens is TTL.
34.167 ≦ f3 / f ≦ 171.011 (17)
29.23 ≦ (R5 + R6) / (R5-R6) ≦ 115.24 (18)
0.03 ≦ d5 / TTL ≦ 0.08 (19) The imaging optical lens according to claim 8, wherein the following conditional expressions (20) to (22) are satisfied.
54.668 ≦ f3 / f ≦ 136.809 (20)
46.77 ≦ (R5 + R6) / (R5-R6) ≦ 92.19 (21)
0.04 ≦ d5 / TTL ≦ 0.07 (22) The fourth lens has a positive refractive power, the object side surface is concave on the paraxial side, and the image side surface is convex on the paraxial side,
The focal length of the fourth lens is f4, the radius of curvature of the object side surface of the fourth lens is R7, the radius of curvature of the image side surface of the fourth lens is R8, the on-axis thickness of the fourth lens is d7, and the imaging optics The imaging optical lens according to claim 1, wherein the following conditional expressions (23) to (25) are satisfied when the optical length of the lens is TTL.
0.80 ≦ f4 / f ≦ 2.43 (23)
0.96 ≦ (R7 + R8) / (R7−R8) ≦ 2.93 (24)
0.05 ≦ d7 / TTL ≦ 0.16 (25) The imaging optical lens according to claim 10, wherein the following conditional expressions (26) to (28) are satisfied.
1.28 ≦ f4 / f ≦ 1.94 (26)
1.53 ≦ (R7 + R8) / (R7−R8) ≦ 2.35 (27)
0.08 ≦ d7 / TTL ≦ 0.13 (28) The fifth lens has a negative refractive power, the object side surface is concave on the paraxial side, and the image side surface is convex on the paraxial side,
The focal length of the fifth lens is f5, the radius of curvature of the object side surface of the fifth lens is R9, the radius of curvature of the image side surface of the fifth lens is R10, the on-axis thickness of the fifth lens is d9, and the imaging optics is The imaging optical lens according to claim 1, wherein the following conditional expressions (29) to (31) are satisfied when the optical length of the lens is TTL.
−8.84 ≦ f5 / f ≦ −2.76 (29)
−20.44 ≦ (R9 + R10) / (R9−R10) ≦ −6.55 (30)
0.03 ≦ d9 / TTL ≦ 0.08 (31) The imaging optical lens according to claim 12, wherein the following conditional expressions (32) to (34) are satisfied.
−5.52 ≦ f5 / f ≦ −3.45 (32)
−12.77 ≦ (R9 + R10) / (R9−R10) ≦ −8.18 (33)
0.04 ≦ d9 / TTL ≦ 0.07 (34) The sixth lens has a negative refractive power, the object side surface is a convex surface in a paraxial direction, and the image side surface is a concave surface in a paraxial direction,
The focal length of the sixth lens is f6, the radius of curvature of the object side surface of the sixth lens is R11, the radius of curvature of the image side surface of the sixth lens is R12, the on-axis thickness of the sixth lens is d11, and the imaging optics is The imaging optical lens according to claim 1, wherein the following conditional expressions (35) to (37) are satisfied when the optical length of the lens is TTL.
−9.16 ≦ f6 / f ≦ −2.92 (35)
2.68 ≦ (R11 + R12) / (R11−R12) ≦ 8.21 (36)
0.09 ≦ d11 / TTL ≦ 0.28 (37) The imaging optical lens according to claim 14, wherein the following conditional expressions (38) to (40) are satisfied.
−5.72 ≦ f6 / f ≦ −3.65 (38)
4.29 ≦ (R11 + R12) / (R11−R12) ≦ 6.57 (39)
0.15 ≦ d11 / TTL ≦ 0.22 (40) The imaging optical lens according to claim 1, wherein the following conditional expression (41) is satisfied when a combined focal length of the first lens and the second lens is f12.
0.70 ≦ f12 / f ≦ 2.14 (41) The imaging optical lens according to claim 16, wherein the following conditional expression (42) is satisfied.
1.13 ≦ f12 / f ≦ 1.71 (42)   The imaging optical lens according to claim 1, wherein an optical length TTL of the imaging optical lens is 5.18 mm or less.   19. The imaging optical lens according to claim 18, wherein the optical length TTL of the imaging optical lens is 4.94 mm or less.   2. The imaging optical lens according to claim 1, wherein the aperture value of the imaging optical lens is 2.27 or less.   21. The imaging optical lens according to claim 20, wherein the aperture F value of the imaging optical lens is 2.22 or less.

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