Photographic wide-angle optical lens

Abstract

The application discloses a photographic wide-angle optical lens and relates to the technical field of optical lenses. The photographic wide-angle optical lens comprises a first lens group with negative optical power, a second lens group with positive optical power and a third lens group with positive optical power which are sequentially arranged along an optical axis from an object side to an image side; the first lens group comprises at least one aspheric lens; an aperture stop is arranged between the second lens group and the third lens group; the first lens group, the second lens group and the third lens group respectively satisfy the following conditional expressions: -3.0<=F1 / F<= -0.8, 2.0<=F2 / F<=4.0 and 2.5<=F3 / F<=4.0, wherein F1 is the lens group focal length of the first lens group, F2 is the lens group focal length of the second lens group, F3 is the lens group focal length of the third lens group and F is the focal length of the photographic wide-angle optical lens. The photographic wide-angle optical lens has a relatively short focal length, a small volume, a higher resolving power and a faster focusing speed.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of optical lens, in particular to a photographic wide-angle optical lens. BACKGROUND

[0002] Some existing wide-angle optical lenses for photography have a lens group structure with a small field of view, and the aperture of the front lens is large, resulting in a large product size and inconvenience for carrying.

[0003] Another lens group structure contains multiple lenses in the focusing lens group of the lens, and the focusing lens group with multiple lenses is heavy, which affects the moving speed of the focusing lens group during focusing, i.e., affects the focusing speed, and noise may exist during focusing. SUMMARY

[0004] The present application aims to at least solve one of the technical problems in the prior art. To this end, the present application provides a photographic wide-angle optical lens with a relatively short focal length, a small size, higher resolving power, and faster focusing speed.

[0005] The photographic wide-angle optical lens according to the embodiment of the present application comprises a first lens group, a second lens group, and a third lens group arranged in sequence along an optical axis from an object side to an image side;

[0006] The first lens group has a negative focal power, and contains at least one aspherical lens;

[0007] The second lens group has a positive focal power;

[0008] The third lens group has a positive focal power;

[0009] An aperture stop is arranged between the second lens group and the third lens group;

[0010] The first lens group, the second lens group, and the third lens group respectively satisfy the following conditional expressions:

[0011] -3.0≤F1 / F≤-0.8,

[0012] 2.0≤F2 / F≤4.0,

[0013] 2.5≤F3 / F≤4.0,

[0014] wherein,

[0015] F1: lens group focal length of the first lens group;

[0016] F2: lens group focal length of the second lens group;

[0017] F3: lens group focal length of the third lens group;

[0018] F: focal length of the photographic wide-angle optical lens.

[0019] The photographic wide-angle optical lens according to the embodiments of the present application has at least the following beneficial effects: the focal length of the photographic wide-angle optical lens satisfying the condition formula is relatively short, the volume is small, and the resolving power is higher; the first lens group satisfies the condition formula, which can reduce the aperture of the first lens group, further miniaturize the volume, reduce the burden of spherical aberration correction of the third lens group, and meanwhile, the refractive power of the first lens group is moderate, and the off-axis aberration is easy to balance and correct; the second lens group satisfies the condition formula, has appropriate refractive power and focusing stroke, and reduces the burden of balancing aberration of the rear group; the third lens group satisfies the condition formula, which can reduce the burden of balancing and correcting off-axis aberration of the aspherical lens, make the surface type of the aspherical lens simpler and easier to process, and meanwhile, realize high-performance resolving power.

[0020] According to some embodiments of the present application, the first lens group comprises 5 lenses.

[0021] According to some embodiments of the present application, from the object side to the image side, the first lens group comprises, in sequence, a first lens with negative refractive power, a second lens with negative refractive power, a third lens with negative refractive power, a fourth lens with positive refractive power, and a fifth lens with negative refractive power.

[0022] According to some embodiments of the present application, the first lens group comprises at least one aspherical lens with negative refractive power.

[0023] According to some embodiments of the present application, the aspherical lens with negative refractive power in the first lens group satisfies the following condition formula:

[0024] -3.0≤Fasp / F≤-1,

[0025] 0.5≤Sasp / F≤1.2,

[0026] wherein,

[0027] Fasp: focal length of the aspherical lens;

[0028] Sasp: sag depth of the concave side of the aspherical lens;

[0029] F: focal length of the photographic wide-angle optical lens.

[0030] According to some embodiments of the present application, the aspherical curve driving equation of the aspherical lens comprised in the first lens group is as follows:

[0031] wherein,

[0032] R: is the radius of asphericity;

[0033] Y: is the radial coordinate;

[0034] K: is the conic coefficient of the quadric;

[0035] Z: is the sagittal height of the surface along the optical axis;

[0036] AR1: is the first asphericity coefficient;

[0037] AR2: is the second asphericity coefficient;

[0038] AR3: is the third asphericity coefficient;

[0039] According to the above rules,

[0040] ARn: is the nth asphericity coefficient.

[0041] According to some embodiments of the present application, the aspheric lens included in the first lens group is a plastic aspheric lens.

[0042] According to some embodiments of the present application, the second lens group only includes a sixth lens with positive focal power.

[0043] According to some embodiments of the present application, during the focusing process from infinity to near distance on the object side, the second lens group moves towards the image side along the optical axis.

[0044] According to some embodiments of the present application, the third lens group includes at least 8 lenses.

[0045] Additional aspects and advantages of the present application will be given in part in the following description, become apparent from the following description, or be learned by practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0046] The present application will be further described below in conjunction with the drawings and embodiments, wherein:

[0047] Figure 1 Fig. 1 is a schematic diagram of the lens arrangement structure of a first wide-angle photographic optical lens according to an embodiment of the present application;

[0048] Figure 2 Fig. 2 is a chromatic aberration diagram of the lens according to the embodiment of the present application; Figure 1

[0049] Fig. 3 is a field curvature diagram of the lens according to the embodiment of the present application; Figure 3 Figure 1 Fig. 4 is a distortion diagram of the lens according to the embodiment of the present application;

[0050] Figure 4 Figure 1 Fig. 5 is a schematic diagram of the lens arrangement structure of a second wide-angle photographic optical lens according to an embodiment of the present application;

[0051] ​​Figure 5 FIG. 1 shows a schematic view of a lens arrangement of a second wide-angle photographic optical lens according to an embodiment of the present application;

[0052] Figure 6 FIG. 2 shows a schematic view of a lens arrangement of a third wide-angle photographic optical lens according to an embodiment of the present application; Figure 5 FIG. 3 shows a chromatic aberration of magnification curve of the lens;

[0053] Figure 7 FIG. 4 shows a field curvature curve of astigmatism of the lens; Figure 5

[0054] Figure 8 FIG. 5 shows a distortion curve of the lens. Figure 5 Reference Signs List:

[0055] The first lens group 100, the second lens group 200, the third lens group 300, and the aperture stop 400.

[0056] DETAILED DESCRIPTION The embodiments of the present application will be described in detail below with reference to the drawings, in which the same or similar components have the same or similar reference numerals throughout the several drawings. The embodiments described below are exemplary and are merely intended to explain the present application, and are not to be understood as limiting the present application.

[0057] In the description of the present application, it should be understood that the positional relationship described, such as up, down, etc., is based on the positional relationship shown in the drawings, and is only for the purpose of facilitating the description of the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0058] In the description of the present application, plural means two or more. If there is a description of first, second, etc., it is only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated or the sequence of technical features indicated.

[0059] In the description of the present application, unless otherwise explicitly limited, the words such as arrangement, installation, connection, etc. should be broadly understood, and the person skilled in the art can reasonably determine the specific meaning of the above words in the present application in combination with the specific content of the technical solution.

[0060] In the description of the present application, unless otherwise explicitly limited, the words such as arrangement, installation, connection, etc. should be broadly understood, and the person skilled in the art can reasonably determine the specific meaning of the above words in the present application in combination with the specific content of the technical solution.

[0061] ​The wide-angle optical lens for photography has a small field of view and a large product size in some existing structures. For example, the patent document with the publication number KR20180119885A discloses multiple embodiments of the lens with a small field of view. The size of the lens is limited by the size of the largest lens, and the lens at the front end has a large aperture, resulting in a large product size.

[0062] Another lens structure, such as the patent document with the publication number CN117706739A, contains multiple lenses in the focusing lens group. For example, as can be seen from the structure of the drawings, the second lens group for focusing has four lenses. The focusing lens group with multiple lenses is heavy, which affects the moving speed of the focusing lens group during focusing, i.e., the focusing speed, and may produce noise during focusing.

[0063] Referring to Figure 1 The wide-angle optical lens for photography has a small field of view and a large product size in some existing structures. For example, the patent document with the publication number KR20180119885A discloses multiple embodiments of the lens with a small field of view. The size of the lens is limited by the size of the largest lens, and the lens at the front end has a large aperture, resulting in a large product size.

[0064] The first lens group 100 has a negative focal power, and at least contains one aspherical lens; the second lens group 200 has a positive focal power; the third lens group 300 has a positive focal power; an aperture stop 400 is arranged between the second lens group 200 and the third lens group 300; the first lens group 100, the second lens group 200 and the third lens group 300 respectively satisfy the following conditional expressions:

[0065] -3.0≤F1 / F≤-0.8 (1),

[0066] 2.0≤F2 / F≤4.0 (2),

[0067] 2.5≤F3 / F≤4.0 (3),

[0068] Wherein, F1: the lens group focal length of the first lens group 100; F2: the lens group focal length of the second lens group 200; F3: the lens group focal length of the third lens group 300; F: the focal length of the wide-angle optical lens for photography.

[0069] The focal length of the photographic wide-angle optical lens satisfying the conditional expression is relatively short, the volume is small, and the resolving power is higher; the first lens group 100 satisfies the conditional expression (1), which can reduce the aperture of the first lens group 100, further miniaturize the volume of the first lens group 100, reduce the burden of spherical aberration correction of the third lens group 300, and the refractive power of the first lens group 100 is moderate, and the off-axis aberration is easy to balance and correct; the second lens group 200 satisfies the conditional expression (2), the second lens group 200 has a suitable refractive power and focusing stroke, and reduces the burden of balancing aberration of the rear group; the third lens group 300 satisfies the conditional expression (3), which can reduce the burden of balancing and correcting off-axis aberration of the aspheric lens in the first lens group 100, make the surface type of the aspheric lens more simple and easy to process, and realize high-performance resolving power.

[0070] More specifically, if the data of the first lens group 100 is less than the lower limit value of the conditional expression (1), the aperture of the first lens group 100 will increase, which is not conducive to the miniaturization of the volume of the first lens group 100. The aperture of the first lens group 100 refers to the size of the largest lens in the lens group. At the same time, if the data of the first lens group 100 is less than the lower limit value of the conditional expression (1), the burden of spherical aberration correction of the third lens group 300 will also increase. If the data of the first lens group 100 is greater than the upper limit value of the conditional expression (1), the refractive power of the first lens group 100 will increase, the angle of the outgoing light rays of the first lens group 100 will become steep, and the off-axis aberration will become difficult to balance and correct.

[0071] If the data of the second lens group 200 is less than the lower limit value of the conditional expression (2), the refractive power of the second lens group 200 will increase, and at the same time the focusing stroke of the second lens group 200 will decrease, but it will also cause the spherical aberration of the second lens group 200 to increase, and the burden of balancing aberration of the rear group will also increase. The rear group refers to the lens group after the second lens group 200 in the direction of the optical path. If the data of the second lens group 200 is greater than the upper limit value of the conditional expression (2), the refractive power of the second lens group 200 will decrease, and at the same time the focusing stroke of the second lens group 200 will increase, but it will also cause the refractive power of the rear group to increase, which is not conducive to balancing the off-axis aberration of the rear group, especially the astigmatism and coma.

[0072] It should be understood that the third lens group 300 has a plurality of lenses, including lenses with positive refractive power and lenses with negative refractive power.

[0073] If the data of the third lens group 300 is less than the lower limit value of conditional expression (3), the refractive power of the third lens group 300 is increased, the refractive power of the lens with positive refractive power contained in the third lens group 300 is increased, the angle of the exiting light is made more steep, the sensitivity of the lens is increased, the burden of the aspheric lens in the first lens group 100 for balancing and correcting the off-axis aberration is increased, and the surface profile of the aspheric lens is made more complex and difficult to process. If the data of the third lens group 300 is greater than the upper limit value of conditional expression (3), the refractive power of the third lens group 300 is decreased, the negative refractive power of the first lens group 100 needs to be decreased in order to maintain the refractive power of the whole lens, the incident light is at a high light height at the first lens group 100, the diameter of the front lens of the first lens group 100 is increased, the spherical aberration is increased, the various aberrations are difficult to balance, and the high performance resolving power is difficult to achieve.

[0074] The first lens group 100 contains at least one aspheric lens. Preferably, the aspheric lens contained in the first lens group 100 contains at least one aspheric lens with negative refractive power.

[0075] It can be understood that the aspheric lens with negative refractive power in the first lens group 100 satisfies the following conditional expression:

[0076] -3.0≤Fasp / F≤-1 (4),

[0077] 0.5≤Sasp / F≤1.2 (5),

[0078] Wherein, Fasp is the focal length of the aspheric lens; Sasp is the sag depth of the concave side of the aspheric lens; F is the focal length of the photographic wide-angle optical lens.

[0079] If the data of the aspheric lens is less than the lower limit value of conditional expression (4), the refractive power of the aspheric lens is decreased, the number of lenses of the first lens group 100 needs to be increased to compensate for the loss of refractive power, and the outer diameter of the first lens group 100 is increased. If the data of the aspheric lens is greater than the upper limit value of conditional expression (4), the refractive power of the aspheric lens is increased, the angle of the exiting light is also increased, and the sensitivity of the aspheric lens is increased.

[0080] If the data of the aspheric lens is less than the lower limit value of conditional expression (5), the surface profile of the edge of the aspheric lens is made flat, the corresponding refractive power is decreased, the number of lenses of the first lens group 100 needs to be increased to compensate for the loss of refractive power, and the outer diameter of the first lens group 100 is increased. If the data of the aspheric lens is greater than the upper limit value of conditional expression (5), the concave side of the aspheric lens is too deep, or the tangent slope of the edge of the lens is too large, and the aspheric lens is difficult to process.

[0081] It can be understood that the aspherical curve driving equation of the aspherical lens included in the first lens group 100 is as follows:

[0082] (6), wherein R: is the aspherical curvature radius; Y: is the radial coordinate; K: is the conic coefficient of the quadratic surface; Z: is the height value of the surface along the optical axis direction; AR1: is the first-order aspherical coefficient; AR2: is the second-order aspherical coefficient; AR3: is the third-order aspherical coefficient; and ARn: is the n-order aspherical coefficient according to the above rule.

[0083] It can be understood that the aspherical lens included in the first lens group 100 is a plastic aspherical lens. Of course, a glass aspherical lens can also be selected, but compared with the glass aspherical lens, the plastic aspherical lens can reduce the cost.

[0084] It can be understood that the first lens group 100 includes five lenses. Preferably, from the object side to the image side, the first lens group 100 includes a first lens with negative focal power, a second lens with negative focal power, a third lens with negative focal power, a fourth lens with positive focal power, and a fifth lens with negative focal power in sequence.

[0085] It can be understood that the second lens group 200 includes only one sixth lens with positive focal power.

[0086] It can be understood that during the focusing process from infinity to near distance on the object side, the second lens group 200 moves towards the image side along the optical axis.

[0087] The second lens group 200 as a focusing group is composed of one sixth lens with positive angle, and the focusing group has less number of lenses, low weight, and high focusing speed.

[0088] It can be understood that the third lens group 300 includes at least eight lenses.

[0089] Embodiment 1:

[0090] The parameters of the wide-angle photographic optical lens of this embodiment are as follows,

[0091] EFL: 10mm;

[0092] Fno: 2.85;

[0093] 2ω: 129.9°;

[0094] Wherein, EFL is the effective focal length of the optical lens, Fno is the aperture, and 2ω is the field of view angle.

[0095] F1 / F = -1.05, which satisfies the condition (1); F2 / F = 2.70, which satisfies the condition (2); F3 / F = 2.93, which satisfies the condition (3); Fasp / F = -2.41, which satisfies the condition (4); Sasp / F = 0.99, which satisfies the condition (5).

[0096] The parameters of the wide-angle photographic optical lens of this embodiment also satisfy the contents of Table 1, Table 2 and Table 3.

[0097] Table 1 Parameters of the wide-angle photographic optical lens of Example 1

[0098]

[0099] In Table 1, Image is the image side; Radius is the radius of curvature of each surface; Thickness is the interval between each lens and the thickness of the lens; Nd is the refractive index of each glass at the d line; Vd is the Abbe number of the glass; ASP indicates that the surface is aspheric.

[0100] Table 2 Focusing interval parameters of the wide-angle photographic optical lens of Example 1

[0101]

[0102] In Table 2, FAR is the far side, i.e. the lens focuses on a distant scene; NEAR is the near side, i.e. the lens focuses on a close scene.

[0103] Table 3 Aspheric lens parameters of the wide-angle photographic optical lens of Example 1

[0104]

[0105] In Table 3, R is the aspheric radius of curvature; K is the conic coefficient of the quadratic surface; AR1 is the 1st order aspheric coefficient; AR2 is the 2nd order aspheric coefficient; AR3 is the 3rd order aspheric coefficient; ARn is the nth order aspheric coefficient according to the above rule. Wherein, 1.246987E-04 means 1.246987 x 10 -4 The rest is the same.

[0106] The lens arrangement structure of the wide-angle photographic optical lens of Example 1 can refer to Figure 1 as shown. And Figure 2 , Figure 3 , Figure 4 The chromatic aberration of the wide-angle photographic optical lens of Example 1, the astigmatic field curve, the distortion map are shown.

[0107] It needs to be understood that in Figure 1In the above, the first lens group 100 is also denoted as G1, the second lens group 200 is also denoted as G2, the third lens group 300 is also denoted as G3, and in the entire wide-angle photographic optical lens, the lens arrangement order from the object side to the image side is that the first lens is L1, the second lens is L2, and the nth lens is Ln in this order. For example, lens G3L10 refers to the 10th lens, and the lens belongs to the third lens group 300. In the above, the aperture stop 400 is denoted as ST0, and the image plane is denoted as IMA.

[0108] Embodiment 2

[0109] The parameters of the wide-angle photographic optical lens of this embodiment are as follows,

[0110] EFL: 10 mm;

[0111] Fno: 2.85;

[0112] 2ω: 130.1°;

[0113] In the above, EFL is the effective focal length of the optical lens, Fno is the aperture, and 2ω is the field of view.

[0114] F1 / F = -1.00, which satisfies condition formula (1); F2 / F = 3.19, which satisfies condition formula (2); F3 / F = 2.99, which satisfies condition formula (3); Fasp / F = -1.98, which satisfies condition formula (4); and Sasp / F = 0.71, which satisfies condition formula (5).

[0115] The parameters of the wide-angle photographic optical lens of this embodiment also satisfy the contents of Table 4, Table 5, and Table 6.

[0116] Table 4. Parameters of the wide-angle photographic optical lens of Embodiment 2

[0117]

[0118] In Table 4, Image is the image side; Radius is the radius of curvature of each surface; Thickness is the interval between lenses and the thickness of the lens; Nd is the refractive index of each glass at the d line; Vd is the Abbe number of the glass; and ASP indicates that the surface is an aspherical surface.

[0119] Table 5. Focus interval parameters of the wide-angle photographic optical lens of Embodiment 2

[0120]

[0121] In Table 5, FAR is the far side, i.e., the lens focuses on a distant scene; and NEAR is the near side, i.e., the lens focuses on a close scene.

[0122] Table 6. Aspherical lens parameters of the wide-angle photographic optical lens of Embodiment 2

[0123]

[0124] In Table 6, R is the aspherical curvature radius; K is the conic coefficient of the quadratic surface; AR1 is the 1st aspherical coefficient; AR2 is the 2nd aspherical coefficient; AR3 is the 3rd aspherical coefficient; and ARn is the nth aspherical coefficient according to the above rule. 2.142710E-04 means 2.142710 x 10-4. -4 The rest is the same.

[0125] The lens arrangement of the wide-angle photographic optical lens of Example 2 can refer to Figure 5 . And Figure 6 , Figure 7 , Figure 8 The chromatic aberration, astigmatism field curve, and distortion map of the wide-angle photographic optical lens of Example 1 are shown.

[0126] It should be understood that in Figure 5 , the first lens group 100 is also recorded as G1, the second lens group 200 is also recorded as G2, the third lens group 300 is also recorded as G3, and in the entire wide-angle photographic optical lens, the lens arrangement order from the object side to the image side is that the first lens is L1, the second lens is L2, and the nth lens is Ln in this order. For example, the lens G3L10 means the 10th lens, and the lens belongs to the third lens group 300. The aperture stop 400 is recorded as ST0, and the image plane is recorded as IMA.

[0127] The embodiments of the present application are described in detail above in combination with the drawings, but the present application is not limited to the above embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the purpose of the present application.

Claims

1. A photographic wide-angle optical lens characterized in that, Consist of first lens group (100), second lens group (200) and third lens group (300): The first lens group (100), the second lens group (200) and the third lens group (300) are sequentially arranged along the optical axis from the object side to the image side: The first lens group (100) has negative focal power, the first lens group (100) contains at least one aspheric lens, and from the object side to the image side, the first lens group (100) consists of a first lens with negative focal power, a second lens with negative focal power, a third lens with negative focal power, a fourth lens with positive focal power and a fifth lens with negative focal power: The second lens group (200) has positive focal power, and the second lens group (200) only includes a sixth lens with positive focal power; The third lens group (300) has positive focal power, from the object side to the image side, the third lens group (300) consists of 8 lenses with positive focal power, negative focal power, positive focal power, negative focal power, positive focal power, negative focal power, positive focal power, positive focal power, or 10 lenses with negative focal power, positive focal power, negative focal power, positive focal power, positive focal power, negative focal power, positive focal power, negative focal power, positive focal power, positive focal power; The second lens group (200) and the third lens group (300) are provided with an aperture stop (400); During the focusing process from infinity to near distance on the object side, the second lens group (200) moves towards the image side along the optical axis; The first lens group (100), the second lens group (200) and the third lens group (300) respectively satisfy the following conditional expressions: -3.0≤F1 / F≤-0.8 (1), 2.0≤F2 / F≤4.0 (2), 2.93≤F3 / F≤2.99 (3), Wherein, F1: the lens group focal length of the first lens group (100); F2: the lens group focal length of the second lens group (200); F3: the lens group focal length of the third lens group (300); F: the focal length of the photographic wide-angle optical lens.

2. The photographic wide-angle optical lens of claim 1, wherein, The aspheric lens contained in the first lens group (100) at least has an aspheric lens with negative focal power.

3. The photographic wide-angle optical lens of claim 2, wherein, The aspheric lens with negative focal power in the first lens group (100) satisfies the following conditional expressions: -3.0≤Fasp / F≤-1 (4), 0.5≤Sasp / F≤1.2 (5), Wherein, Fasp: the focal length of the aspheric lens; Sasp: the sag depth of the concave side of the aspheric lens; F: the focal length of the photographic wide-angle optical lens.

4. The photographic wide-angle optical lens of claim 2, wherein, The aspheric curve driving equation of the aspheric lens contained in the first lens group (100) is as follows: (6), wherein, R: the aspheric curvature radius; Y: the radial coordinate; K: the conic coefficient of the quadratic surface; Z: the sag value of the surface along the optical axis; AR1: the first order aspheric coefficient; AR2: the second order aspheric coefficient; AR3: the third order aspheric coefficient; According to the above rule, ARn: the n order aspheric coefficient.

5. The photographic wide-angle optical lens of claim 1, wherein, The first lens group (100) comprises a plastic aspherical lens.

Images