KR20230002187A - Lens module - Google Patents

Abstract

A lens module of the present invention includes: a first lens having a positive refractive power; a second lens having a positive refractive power; a third lens having a refractive power; a fourth lens having a positive refractive power; a fifth lens having a refractive power; and a sixth lens having a negative refractive power and having a shape in which an inflection point is formed on an image side surface. The lens module of the present invention satisfies a conditional expression, 0.3 < SD/f < 0.5, wherein SD is the size of a diaphragm hole [mm] and f is a total focal length of the lens module in mm. Accordingly, the lens module can realize high resolution.

Description

Lens module {Lens module}

The present invention relates to a lens module having an optical system composed of 6 lenses.

Recent portable terminals are equipped with cameras to enable video calls and photo taking. In addition, as the function occupied by the camera in the portable terminal gradually increases, the demand for high resolution and high performance of the camera for the portable terminal is gradually increasing.

However, since portable terminals tend to become smaller or lighter, there is a limit to implementing high-resolution and high-performance cameras.

In order to solve this problem, recently, a lens of a camera is made of a plastic material that is lighter than glass, and a lens module is composed of 5 or more lenses to realize high resolution.

However, a lens made of plastic is difficult to improve chromatic aberration compared to a lens made of glass, and it is difficult to implement a relatively bright optical system.

For reference, prior art related to the present invention includes Patent Documents 1 to 4.

KR 2008-0057738 A KR 2008-0061461 A JP 2011-085733 A US 2012-0194726 A1

The present invention is to solve the above problems, and an object of the present invention is to provide a lens module capable of implementing high resolution.

A lens module according to an embodiment of the present invention for achieving the above object includes a first lens having a positive refractive power; a second lens having positive refractive power; a third lens having refractive power; a fourth lens having positive refractive power; a fifth lens having refractive power; and a sixth lens having negative refractive power and having a shape in which an inflection point is formed on an image side surface, and may satisfy the following conditional expression.

[Conditional Expression] 0.36 < SD/f < 0.48

In the above conditional expression, SD is the size of the diaphragm hole [mm], and f is the total focal length of the lens module [mm].

In the lens module according to an embodiment of the present invention, the third lens may have negative refractive power.

In the lens module according to an embodiment of the present invention, the first lens may have a shape in which an object side surface is convex and an image side surface is concave.

In the lens module according to an embodiment of the present invention, the second lens may have a shape in which an object side surface is convex and an image side surface is convex.

In the lens module according to an embodiment of the present invention, the third lens may have a shape in which an object side surface is convex and an image side surface is concave.

In the lens module according to an embodiment of the present invention, the fourth lens may have a shape in which an object side surface is concave and an image side surface is convex.

In the lens module according to an embodiment of the present invention, the fifth lens may have a shape in which an object side surface is concave and an image side surface is convex.

In the lens module according to an embodiment of the present invention, the sixth lens may have a convex object side surface and a concave image side surface.

In the lens module according to an embodiment of the present invention, the sixth lens may have a shape in which an inflection point is formed on a side surface of an object.

A lens module according to an embodiment of the present invention may satisfy the following conditional expression.

[Conditional expression] 1.1 < TTL/f < 1.4

In the above conditional expression, TTL is the distance from the object side of the first lens to the image surface [mm], and f is the total focal length of the lens module [mm].

A lens module according to an embodiment of the present invention may satisfy the following conditional expression.

[Conditional expression] V4 - V5 < 5.0

In the above conditional expression, V4 is the Abbe's number of the fourth lens, and V5 is the Abbe's number of the fifth lens.

A lens module according to an embodiment of the present invention may satisfy the following conditional expression.

[conditional expression] |R2| - |R1| > 0

In the above conditional expression, R1 is the radius of curvature [mm] of the object side of the first lens, and R2 is the radius of curvature [mm] of the image side of the first lens.

A lens module according to an embodiment of the present invention may satisfy the following conditional expression.

[conditional expression] SA < 36

In the above conditional expression, SA is the sweep angle of the image side of the sixth lens.

A lens module according to another embodiment of the present invention for achieving the above object includes a first lens having a positive refractive power; a second lens having positive refractive power; a third lens having refractive power; a fourth lens having positive refractive power; a fifth lens having refractive power; and a sixth lens having negative refractive power, and may satisfy the following conditional expression.

[conditional expression] V5 < 30

In the conditional expression above, V5 is the Abbe's number of the fifth lens.

In the lens module according to another embodiment of the present invention, the third lens may have negative refractive power.

In the lens module according to another embodiment of the present invention, the first lens may have a shape in which an object side surface is convex and an image side surface is concave.

In the lens module according to another embodiment of the present invention, the second lens may have a shape in which an object side surface is convex and an image side surface is convex.

In the lens module according to another embodiment of the present invention, the third lens may have a shape in which an object side surface is convex and an image side surface is concave.

In the lens module according to another embodiment of the present invention, the fourth lens may have a shape in which an object side surface is concave and an image side surface is convex.

In the lens module according to another embodiment of the present invention, the fifth lens may have a shape in which an object side surface is concave and an image side surface is convex.

In the lens module according to another embodiment of the present invention, the sixth lens may have a shape in which an object side surface is convex and an image side surface is concave.

In the lens module according to another embodiment of the present invention, the sixth lens may have a shape in which an inflection point is formed on a side surface of an object.

A lens module according to another embodiment of the present invention may satisfy the following conditional expression.

[Conditional expression] 1.1 < TTL/f < 1.4

In the above conditional expression, TTL is the distance from the object side of the first lens to the image surface [mm], and f is the total focal length of the lens module [mm].

A lens module according to another embodiment of the present invention may satisfy the following conditional expression.

[Conditional expression] V4 - V5 < 5.0

In the above conditional expression, V4 is the Abbe's number of the fourth lens, and V5 is the Abbe's number of the fifth lens.

A lens module according to another embodiment of the present invention may satisfy the following conditional expression.

[conditional expression] |R2| - |R1| > 0

In the above conditional expression, R1 is the radius of curvature [mm] of the object side of the first lens, and R2 is the radius of curvature [mm] of the image side of the first lens.

A lens module according to another embodiment of the present invention may satisfy the following conditional expression.

[conditional expression] SA < 36

In the above conditional expression, SA is the sweep angle of the image side of the sixth lens.

A lens module according to another embodiment of the present invention may satisfy the following conditional expression.

[Conditional Expression] 0.36 < SD/f < 0.48

In the above conditional expression, SD is the size of the diaphragm hole [mm], and f is the total focal length of the lens module [mm].

The present invention can implement high resolution.

1 is a configuration diagram of a lens module according to an embodiment of the present invention;
2 and 3 are curves showing aberration characteristics of the lens module shown in FIG. 1,
4 and 5 are tables showing the characteristics of the lens module shown in FIG. 1,
6 is a configuration diagram of a lens module according to another embodiment of the present invention;
7 and 8 are curves showing aberration characteristics of the lens module shown in FIG. 6;
9 and 10 are tables showing characteristics of the lens module shown in FIG. 6 .

Hereinafter, preferred embodiments of the present invention will be described in detail based on the accompanying drawings.

In describing the present invention below, terms referring to the components of the present invention are named in consideration of the functions of each component, so they should not be understood as limiting the technical components of the present invention.

In addition, throughout the specification, that a component is 'connected' to another component includes not only the case where these components are 'directly connected', but also the case where they are 'indirectly connected' through other components. means that In addition, 'including' a certain component means that other components may be further included, rather than excluding other components unless otherwise stated.

In addition, in this specification, the first lens means a lens closest to the object side, and the sixth lens means a lens closest to the image side. In addition, the front side means a side closer to the object side of the lens module, and the rear side means a side closer to the image sensor in the lens module. Also, in each lens, the first surface means a surface close to the object side (or object side surface), and the second surface means a surface close to the image side (or image side surface). In addition, in this specification, the units for the radius of curvature of the lens, thickness, TTL, SL, IMGH, the total focal length of the optical system, and the focal length of each lens are all in mm. In addition, in the description of the shape of the lens, the convex shape of one surface means that the optical axis portion of the corresponding surface is convex, and the concave shape of one surface means that the optical axis portion of the corresponding surface is concave. Therefore, even if one surface of the lens is described as having a convex shape, the edge portion of the lens may be concave. Likewise, even if one surface of the lens is described as having a concave shape, the edge portion of the lens may be convex.

1 is a configuration diagram of a lens module according to an embodiment of the present invention, FIGS. 2 and 3 are curves showing aberration characteristics of the lens module shown in FIG. 1, and FIGS. 4 and 5 are shown in FIG. A table showing characteristics of a lens module, FIG. 6 is a configuration diagram of a lens module according to another embodiment of the present invention, FIGS. 7 and 8 are curves showing aberration characteristics of the lens module shown in FIG. 6, and FIG. 9 and FIG. 10 is a table showing characteristics of the lens module shown in FIG. 6 .

The lens module according to the present invention may include an optical system composed of 6 lenses. In other words, the lens module may include a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens. However, the lens module does not consist of only 6 lenses and may further include other components as needed. For example, the lens module may include a stop for adjusting the amount of light. In addition, the lens module may further include an infrared cut filter for blocking infrared rays. In addition, the lens module may further include an image sensor (ie, an imaging device) for converting an image of a subject incident through an optical system into an electrical signal. In addition, the lens module may further include a space maintaining member for adjusting a distance between the lenses.

The first to sixth lenses constituting the optical system may be made of a plastic material. In addition, at least one of the first to sixth lenses may have an aspherical surface. Also, the first to sixth lenses may have at least one aspherical surface. That is, at least one of the first and second surfaces of the first to sixth lenses may be an aspherical surface.

In addition, an optical system composed of the first to sixth lenses may have an F No. of 2.4 or less. In this case, it may be possible to capture a clear subject. For example, the lens module according to the present invention can capture an image of a subject clearly even under low light conditions (eg, 100 lux or less).

An optical system including the first to sixth lenses may satisfy Conditional Expression 1.

[Conditional Expression 1] 0.36 < SD/f < 0.48

In Conditional Expression 1, SD is the diameter of the diaphragm hole [mm], and f is the total focal length of the optical system [mm].

An optical system including the first to sixth lenses may satisfy Conditional Expression 2.

[Conditional Expression 2] 1.1 < TTL/f < 1.35

In Condition 2, TTL is the length from the first surface to the image surface of the first lens [mm], and f is the total focal length of the optical system [mm].

Here, it is difficult to secure optical performance of a lens module exceeding the lower limit of Conditional Expression 2, and miniaturization of a lens module exceeding the upper limit of Conditional Expression 2 may be difficult.

An optical system including the first to sixth lenses may satisfy Conditional Expression 3.

[Conditional Expression 3] V4 - V5 < 5.0

In Condition 3, V4 is the Abbe value of the fourth lens, and V5 is the Abbe value of the fifth lens.

Here, a lens module that satisfies Conditional Expression 3 can be easily miniaturized.

An optical system including the first to sixth lenses may satisfy Conditional Expression 4.

[Conditional Expression 4] |R2| > |R1|

In Conditional Expression 4, R2 is the radius of curvature [mm] of the second surface of the first lens, and R1 is the radius of curvature of the first surface of the first lens [mm].

Here, the first lens that satisfies conditional expression 4 is easy to manufacture and can lower sensitivity according to manufacturing tolerance.

An optical system including the first to sixth lenses may satisfy Conditional Expression 5.

[Conditional Expression 5] SA < 36

In Condition 5, SA is the sweep angle of the second surface of the sixth lens.

Here, conditional expression 5 may be a numerical condition for minimizing total reflection of the sixth lens. For example, a lens module outside the upper limit of Conditional Expression 5 is prone to internal reflection.

An optical system including the first to sixth lenses may satisfy Conditional Expression 6.

[Conditional Expression 6] 0 < f1/f4 < 0.8

In Conditional Expression 6, f1 is the focal length [mm] of the first lens, and f4 is the focal length [mm] of the fourth lens.

An optical system including the first to sixth lenses may satisfy Conditional Expression 7.

[Conditional Expression 7] f5/f6 > 0.8

In Conditional Expression 7, f5 is the focal length [mm] of the fifth lens, and f6 is the focal length [mm] of the sixth lens.

Next, the first to sixth lenses constituting the optical system will be described.

The first lens may have refractive power. For example, the first lens may have positive refractive power. The first lens may have a shape in which a first surface is convex and a second surface is concave. For example, the first lens may have a meniscus shape convex toward the object side. At least one surface of the first surface and the second surface of the first lens may be an aspheric surface. For example, both surfaces of the first lens may be aspherical. The first lens may be made of a material having high light transmittance and excellent workability. For example, the first lens may be made of a plastic material. However, the material of the first lens is not limited to plastic. For example, the first lens may be made of a glass material.

The second lens may have refractive power. For example, the second lens may have positive refractive power. The second lens may have a convex shape on both sides. At least one surface of the first surface and the second surface of the second lens may be an aspherical surface. For example, both surfaces of the second lens may be aspherical. The second lens may be made of a material having high light transmittance and excellent workability. For example, the second lens may be made of a plastic material. However, the material of the second lens is not limited to plastic. For example, the second lens may be made of a glass material.

The third lens may have refractive power. For example, the third lens may have negative refractive power. The third lens may have a concave shape on both sides. Alternatively, the third lens may have a shape in which the first surface is convex and the second surface is concave. For example, the third lens may have a meniscus shape convex to the object side or a plano-convex shape convex to the object side. At least one surface of the first surface and the second surface of the third lens may be an aspheric surface. For example, both surfaces of the third lens may be aspherical. The third lens may be made of a material having high light transmittance and excellent workability. For example, the third lens may be made of a plastic material. However, the material of the third lens is not limited to plastic. For example, the third lens may be made of a glass material. In addition, the third lens may have a smaller diameter than the first and second lenses. For example, the effective diameter of the third lens (that is, the diameter of the part where effective light is substantially incident and refracted) may be smaller than the effective diameters of the first and second lenses.

The fourth lens may have refractive power. For example, the fourth lens may have positive refractive power. The fourth lens may have a shape in which a first surface is concave and a second surface is convex. For example, the fourth lens may have a meniscus shape convex to the image side or a plano-convex shape convex to the image side. At least one surface of the first surface and the second surface of the fourth lens may be an aspherical surface. For example, both surfaces of the fourth lens may be aspherical. The fourth lens may be made of a material having high light transmittance and excellent workability. For example, the fourth lens may be made of a plastic material. However, the material of the fourth lens is not limited to plastic. For example, the fourth lens may be made of a glass material.

The fifth lens may have refractive power. For example, the fifth lens may have negative refractive power. The fifth lens may have a shape in which a first surface is concave and a second surface is convex. For example, the fifth lens may have a meniscus shape convex to the image side. At least one surface of the first surface and the second surface of the fifth lens may be an aspheric surface. For example, both surfaces of the fifth lens may be aspherical. The fifth lens may be made of a material having high light transmittance and excellent workability. For example, the fifth lens may be made of a plastic material. However, the material of the fifth lens is not limited to plastic. For example, the fifth lens may be made of a glass material.

The sixth lens may have refractive power. For example, the sixth lens may have negative refractive power. The sixth lens may have a shape in which a first surface is convex and a second surface is concave. In addition, the sixth lens may have a shape in which an inflection point is formed on at least one surface. For example, the second surface of the sixth lens may be concave at the center of the optical axis and convex toward the edge. At least one surface of the first surface and the second surface of the sixth lens may be an aspherical surface. For example, both surfaces of the sixth lens may be aspherical. The sixth lens may be made of a material having high light transmittance and excellent workability. For example, the sixth lens may be made of a plastic material. However, the material of the sixth lens is not limited to plastic. For example, the sixth lens may be made of a glass material.

Meanwhile, in the lens module according to the attached embodiments, the lenses may be disposed such that the effective diameter of the lens decreases from the first lens to the third lens and increases from the fourth lens to the sixth lens. . The optical system configured as described above may increase the amount of light projected onto the image sensor, thereby improving the resolution of the lens module.

The lens module configured as above can improve aberration that causes image quality deterioration. In addition, the lens module configured as above can improve resolution. In addition, the lens module configured as described above may be advantageous in light weight and lower manufacturing cost.

A lens module according to an embodiment of the present invention will be described with reference to FIGS. 1, 2, 3, 4, and 5.

The lens module 100 according to the present embodiment includes a first lens 10, a second lens 20, a third lens 30, a fourth lens 40, a fifth lens 50, and a sixth lens ( 60), and may further include an infrared cut filter 70 and an image sensor 80.

In this embodiment, the first lens 10 may have positive refractive power. In addition, the first lens 10 may have a convex first surface and a concave second surface. The second lens 20 may have positive refractive power. In addition, the second lens 20 may have a convex shape on both sides. The third lens 30 may have negative refractive power. In addition, the third lens 30 may have a convex first surface and a concave second surface. The fourth lens 40 may have positive refractive power. In addition, the fourth lens 40 may have a shape in which a first surface is concave and a second surface is convex. The fifth lens 50 may have negative refractive power. In addition, the fifth lens 50 may have a shape in which a first surface is concave and a second surface is convex. The sixth lens 60 may have negative refractive power. In addition, the sixth lens 60 may have a convex first surface and a concave second surface. Also, the sixth lens 60 may have an inflection point. For example, an inflection point may be formed on the second surface of the sixth lens 60 .

The lens module 100 according to this embodiment may include one or more diaphragms ST. For example, the diaphragm ST may be disposed between the second lens 20 and the third lens 30 . The first diaphragm ST disposed as described above may perform functions of adjusting the amount of light and vignetting.

The lens module configured as described above may have aberration characteristics shown in FIGS. 2 and 3 and may have lens characteristics shown in FIGS. 4 and 5 . For reference, FIG. 4 is a table showing the radius of curvature, thickness and distance of the lens, and FIG. 5 is a table showing the aspheric surface value of the lens.

For example, A(1) in FIG. 4 represents the radius of curvature of the object side of the first lens, and A(2) of FIG. 4 represents the radius of curvature of the image side of the first lens. Here, the values of A(1), A(2), and A(i) can be calculated through FIG. 5 . For example, the value corresponding to A(1) in FIG. 4 is the reciprocal of the value corresponding to A(1) on the vertical axis and CURV on the horizontal axis in FIG. 5 . For example, the radius of curvature (A(5)) of the side of the object of the third lens 30 is 9.138 [mm], which is the reciprocal of 0.109435 corresponding to A(5) on the vertical axis and CURV on the horizontal axis in FIG. As another example, the radius of curvature (A(8)) of the image side of the fourth lens 40 is -6.155 [mm], which is the reciprocal of -0.162472 corresponding to A(8) on the vertical axis and CURV on the horizontal axis in FIG.

In addition, the thickness of each lens and the distance between the lenses can be confirmed through FIG. 4 . For example, the thickness of the first lens 10 is 0.49 [mm] corresponding to 1 on the vertical axis and the thickness/distance on the horizontal axis in FIG. 4, and the distance between the first lens 10 and the second lens 20 is described above. It is 0.0995 [mm] described below the value.

In addition, the refractive index and Abbe number of each lens can be confirmed through the GLA value of FIG. 4 . For example, the second lens 20 has a refractive index of 1.544 and an Abbe number of 56.0. As another example, the refractive index of the third lens 30 is 1.639 and the Abbe number is 23.0.

Next, a lens module according to another embodiment of the present invention will be described with reference to FIGS. 6, 7, 8, 9, and 10 .

The lens module 100 according to the present embodiment includes a first lens 10, a second lens 20, a third lens 30, a fourth lens 40, a fifth lens 50, and a sixth lens ( 60), and may further include an infrared cut filter 70 and an image sensor 80.

In this embodiment, the first lens 10 may have positive refractive power. In addition, the first lens 10 may have a convex first surface and a concave second surface. The second lens 20 may have positive refractive power. In addition, the second lens 20 may have a convex shape on both sides. The third lens 30 may have negative refractive power. In addition, the third lens 30 may have a convex first surface and a concave second surface. The fourth lens 40 may have positive refractive power. In addition, the fourth lens 40 may have a shape in which a first surface is concave and a second surface is convex. The fifth lens 50 may have negative refractive power. In addition, the fifth lens 50 may have a shape in which a first surface is concave and a second surface is convex. The sixth lens 60 may have negative refractive power. In addition, the sixth lens 60 may have a convex first surface and a concave second surface. Also, the sixth lens 60 may have an inflection point. For example, an inflection point may be formed on the second surface of the sixth lens 60 .

The lens module 100 according to this embodiment may include one or more diaphragms ST. For example, the diaphragm ST may be disposed between the second lens 20 and the third lens 30 . The first diaphragm ST disposed as described above may perform functions of adjusting the amount of light and vignetting.

The lens module configured as described above may have aberration characteristics shown in FIGS. 7 and 8 and may have lens characteristics shown in FIGS. 9 and 10 . For reference, FIG. 9 is a table showing the radius of curvature, thickness and distance of the lens, and FIG. 10 is a table showing the aspheric surface value of the lens.

For example, A(3) in FIG. 9 represents the radius of curvature of the object side of the second lens, and A(4) of FIG. 9 represents the radius of curvature of the image side of the second lens. Here, the values of A(1), A(2), and A(i) can be calculated through FIG. 10 . For example, the value corresponding to A(3) in FIG. 9 is the reciprocal of the value corresponding to A(3) on the vertical axis and CURV on the horizontal axis in FIG. 10 . For example, the radius of curvature A(3) of the side of the object of the second lens 20 is 2.302 [mm], which is the reciprocal of 0.434377 corresponding to A(3) on the vertical axis and CURV on the horizontal axis in FIG. 10 . As another example, the radius of curvature A(4) of the image side of the second lens 20 is -147.102 [mm], which is the reciprocal of -0.006798 corresponding to A(4) on the vertical axis and CURV on the horizontal axis in FIG. 10.

In addition, the thickness of each lens and the distance between the lenses can be confirmed through FIG. 9 . For example, the thickness of the third lens 30 is 0.28 [mm] corresponding to the thickness/distance of 3 on the vertical axis and the horizontal axis in FIG. 9, and the distance between the third lens 30 and the fourth lens 40 is the above. It is 0.45 [mm] described below the value.

In addition, the refractive index and Abbe number of each lens can be confirmed through the GLA value of FIG. 10 . For example, the refractive index of the fifth lens 50 is 1.639 and the Abbe number is 23.0.

Although each embodiment configured as above has some differences in some optical characteristics as shown in Table 1, it satisfies all Conditional Expressions 1 to 7 of the present invention.

The present invention is not limited to the embodiments described above, and those skilled in the art can do so without departing from the gist of the technical idea of the present invention described in the claims below. It can be implemented by making various changes.

10 1st lens
20 2nd lens
30 3rd lens
40 4th lens
50 Fifth Lens
60 6th lens
70 Infrared Cut Filter
80 image sensor

Claims (12)

A first lens having refractive power and having a concave image side surface;
a second lens having positive refractive power;
a third lens having negative refractive power;
a fourth lens having refractive power and having a concave object side surface;
a fifth lens having negative refractive power; and
a sixth lens having refractive power and having a concave image side surface;
including,
The first lens to the sixth lens are sequentially disposed from the object side, and the lens module satisfies the following conditional expression.
0.8 < f5/f6
(In the conditional expression, f5 is the focal length of the fifth lens, and f6 is the focal length of the sixth lens) According to claim 1,
A lens module that satisfies the following conditional expression.
0.36 < SD/f < 0.48
(In the above conditional expression, SD is the size of the aperture hole, and f is the total focal length of the lens module) According to claim 1,
A lens module that satisfies the following conditional expression.
1.1 < TTL/f < 1.35
(In the above conditional expression, TTL is the length from the object side of the first lens to the image surface, and f is the total focal length of the lens module) According to claim 1,
A lens module that satisfies the following conditional expression.
V4 - V5 < 5
(In the above conditional expression, V4 is the Abbe number of the fourth lens, and V5 is the Abbe number of the fifth lens) According to claim 1,
A lens module that satisfies the following conditional expression.
|R2| > |R1|
(In the above conditional expression, R1 is the radius of curvature [mm] of the object side of the first lens, and R2 is the radius of curvature of the image side of the first lens [mm]) According to claim 1,
A lens module that satisfies the following conditional expression.
SA < 36°
(In the conditional expression, SA is the sweep angle of the image side of the sixth lens) According to claim 1,
A lens module that satisfies the following conditional expression.
V5 < 30
(In the above conditional expression, V5 is the Abbe number of the fifth lens) According to claim 1,
A lens module that satisfies the following conditional expression.
0 < f1/f4 < 0.8
(In the conditional expression, f1 is the focal length [mm] of the first lens, and f4 is the focal length [mm] of the fourth lens) According to claim 1,
The second lens has a shape in which an object side surface is convex. According to claim 1,
The lens module of claim 1 , wherein the third lens has a shape in which an object side surface is convex. According to claim 1,
The fifth lens is a lens module having a concave object side surface. According to claim 1,
The sixth lens has a shape in which an inflection point is formed on an image side surface.

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