KR102372999B1 - Lens module - Google Patents

Abstract

The lens module of the present invention 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 a negative refractive power and having a shape in which an inflection point is formed on an image side, and may satisfy the following conditional expression.
[Conditional Expression] 0.3 < SD/f < 0.5
In the above conditional expression, SD is the size of the aperture hole [mm], and f is the total focal length [mm] of the lens module.

Description

Lens module

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

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

However, since portable terminals are gradually becoming smaller or lighter, there is a limit to realizing a high-resolution and high-performance camera.

In order to solve this problem, recently, the lens of the 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, it is difficult for a plastic lens to improve chromatic aberration and to implement a relatively bright optical system compared to a glass lens.

For reference, as prior art related to the present invention, there are 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 realizing 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 a negative refractive power and a shape in which an inflection point is formed on an image side, 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 aperture hole [mm], and f is the total focal length [mm] of the lens module.

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

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

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

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

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

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

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

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.

The 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 [mm] from the object side of the first lens to the image plane, and f is the total focal length [mm] of the lens module.

The 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.

The 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 of the object side of the first lens [mm], and R2 is the radius of curvature of the image side of the first lens [mm].

The 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 above conditional expression, V5 is the Abbe number of the fifth lens.

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

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

In the lens module according to another embodiment of the present invention, the second lens may have a convex object side and a convex image side.

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

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

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

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

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.

The 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 [mm] from the object side of the first lens to the image plane, and f is the total focal length [mm] of the lens module.

The 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.

The 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 of the object side of the first lens [mm], and R2 is the radius of curvature of the image side of the first lens [mm].

The 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.

The 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 aperture hole [mm], and f is the total focal length [mm] of the lens module.

The present invention can realize high resolution.

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

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

In describing the present invention below, terms referring to the components of the present invention are named in consideration of the function of each component, and thus should not be construed as limiting the technical components of the present invention.

In addition, throughout the specification, that a component is 'connected' with another component includes not only cases where these components are 'directly connected' but also '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 the present specification, the first lens means the lens closest to the object side, and the sixth lens means the lens closest to the image side. In addition, the front means a side closer to the object in the lens module, and the rear means a side near the image sensor in the lens module. In addition, 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 the present specification, the units for the radius of curvature of the lens, the thickness (Thickness), TTL, SL, IMGH, the total focal length of the optical system, and the focal length of each lens are in mm units. 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 means that the optical axis portion of the corresponding surface is concave. Therefore, even if it is described that one surface of the lens has a convex shape, the edge portion of the lens may be concave. Similarly, although one surface of the lens is described as having a concave shape, the edge portion of the lens may be convex.

1 is a block 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. It is a table showing the characteristics of the lens module, FIG. 6 is a block diagram of a lens module according to another embodiment of the present invention, FIGS. 7 and 8 are curves showing the 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 six lenses. In more detail, 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 is not composed of only six lenses and may further include other components as necessary. 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 the image of the subject incident through the optical system into an electrical signal. In addition, the lens module may further include a spacing member for adjusting the distance between the lens and the lens.

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 aspherical.

In addition, the 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 photograph a clear subject. For example, the lens module according to the present invention can capture an image of a subject clearly even in low light conditions (eg, 100 lux or less).

The optical system including the first to sixth lenses may satisfy Condition Equation 1.

[Condition 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].

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

[Condition 2] 1.1 < TTL/f < 1.35

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

Here, it may be difficult to secure optical performance for a lens module that deviates from the lower limit of Conditional Expression 2, and it may be difficult to miniaturize a lens module that deviates from the upper limit of Conditional Expression 2.

The optical system including the first to sixth lenses may satisfy Condition Equation 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, the lens module satisfying condition 3 may be easily downsized.

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

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

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

Here, the first lens that satisfies Conditional Equation 4 can be easily manufactured in shape and can reduce sensitivity according to manufacturing tolerances.

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

[Conditional Expression 5] SA < 36

In condition 5, SA is a 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, in a lens module that deviates from the upper limit of Conditional Expression 5, internal reflection is likely to occur.

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

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

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

The 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 convex first surface and a concave second surface. For example, the first lens may have a meniscus shape convex toward the object. At least one of the first surface and the second surface of the first lens may be an aspherical 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 shape in which both surfaces are convex. At least one 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 a negative refractive power. The third lens may have a shape in which both surfaces are concave. Alternatively, the third lens may have a convex first surface and a concave second surface. For example, the third lens may have a meniscus shape convex toward the object or a plano-convex shape convex toward the object. At least one of the first surface and the second surface of the third lens may be an aspherical 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 (ie, the diameter of a portion where the effective light is substantially incident and refracted) may be smaller than the effective diameters of the first lens and the second lens.

The fourth lens may have refractive power. For example, the fourth lens may have positive refractive power. The fourth lens may have a concave first surface and a convex second surface. For example, the fourth lens may have a meniscus shape convex toward the image side or a plano-convex shape convex toward the image side. At least one 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 concave first surface and a convex second surface. For example, the fifth lens may have a meniscus shape convex toward the image. At least one of the first surface and the second surface of the fifth lens may be an aspherical 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 convex first surface and a concave second surface. 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 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 arranged such that the effective diameter of the lens decreases from the first lens to the third lens, and the effective diameter of the lens increases from the fourth lens to the sixth lens. . The optical system configured as described above can increase the amount of light projected to the image sensor, thereby improving the resolution of the lens module.

The lens module configured as described above can improve aberrations that cause 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 lightening the weight and lowering the 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 a 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 shape in which both sides are convex. 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 concave first surface and a convex second surface. The fifth lens 50 may have a negative refractive power. In addition, the fifth lens 50 may have a concave first surface and a convex second surface. The sixth lens 60 may have a 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 the present embodiment may include one or more apertures ST. For example, the stopper ST may be disposed between the second lens 20 and the third lens 30 . The first iris ST arranged as described above may perform functions of adjusting the amount of light and vignetting.

The lens module configured as described above may have the aberration characteristic shown in FIGS. 2 and 3 , and may have the lens characteristic 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 value of the lens.

For example, A(1) of FIG. 4 indicates a radius of curvature of an object side surface of the first lens, and A(2) of FIG. 4 indicates a radius of curvature of an image side surface of the first lens. Here, the values of A(1), A(2), and A(i) may be calculated through FIG. 5 . For example, a value corresponding to A(1) in FIG. 4 is the inverse of a 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 surface 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. 5 . 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. 5 .

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 the above It is 0.0995 [mm] described below the value.

In addition, the refractive index and Abbe's number of each lens can be confirmed through the GLA value of FIG. 4 . For example, the refractive index of the second lens 20 is 1.544, and the Abbe's number is 56.0. As another example, the refractive index of the third lens 30 is 1.639, and the Abbe's 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 a 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 shape in which both sides are convex. 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 concave first surface and a convex second surface. The fifth lens 50 may have a negative refractive power. In addition, the fifth lens 50 may have a concave first surface and a convex second surface. The sixth lens 60 may have a 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 the present embodiment may include one or more apertures ST. For example, the stopper ST may be disposed between the second lens 20 and the third lens 30 . The first iris ST arranged as described above may perform functions of adjusting the amount of light and vignetting.

The lens module configured as described above may have the aberration characteristic shown in FIGS. 7 and 8 , and may have the lens characteristic 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 value of the lens.

For example, A(3) of FIG. 9 indicates the radius of curvature of the object side of the second lens, and A(4) of FIG. 9 indicates the radius of curvature of the image side of the second lens. Here, the values of A(1), A(2), and A(i) may be calculated through FIG. 10 . For example, the value corresponding to A(3) in FIG. 9 is the inverse 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 object side 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 3 of the vertical axis and the thickness/distance of 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's 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's number is 23.0.

As shown in Table 1, each of the embodiments configured as above has some differences in some optical properties, but all of the conditional expressions 1 to 7 of the present invention are satisfied.

The present invention is not limited only to the embodiments described above, and those of ordinary skill in the art to which the present invention pertains can freely do without departing from the spirit of the present invention described in the claims below. It may be implemented with various modifications.

10 first lens
20 second lens
30 third lens
40 4th lens
50 fifth lens
60 6th lens
70 infrared cut filter
80 image sensor

Claims (14)

A first lens having refractive power, the object side is convex and the image side is concave;
a second lens having refractive power and having a convex side surface of the object;
a third lens having a negative refractive power and having a convex side surface of the object;
a fourth lens having positive refractive power and having a convex image side;
a fifth lens having refractive power; and
a sixth lens having a negative refractive power and having a concave image side and a shape in which an inflection point is formed on the image side;
A lens module comprising a. According to claim 1,
The second lens is a lens module having a positive refractive power. delete According to claim 1,
The third lens is a lens module having a concave image side. According to claim 1,
The fifth lens is a lens module having a negative refractive power. According to claim 1,
The fourth lens is a lens module in which the object side has a concave shape. According to claim 1,
The fifth lens is a lens module in which the object side has a concave shape. According to claim 1,
The fifth lens is a lens module having a convex image side. According to claim 1,
The sixth lens is a lens module having a convex shape on the side of the object. According to claim 1,
A lens module satisfying the following conditional expression.
[Conditional Expression] 1.1 < TTL/f < 1.4
(In the above conditional expression, TTL is the distance [mm] from the object side of the first lens to the image plane, and f is the total focal length [mm] of the lens module) According to claim 1,
A lens module satisfying the following conditional expression.
[Conditional Expression] |R2| > |R1|
(In the above conditional expression, R1 is the radius of curvature of the object side of the first lens [mm], and R2 is the radius of curvature of the image side of the first lens [mm]) According to claim 1,
A lens module satisfying the following conditional expression.
[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 satisfying the following conditional expression.
[Conditional Expression] 0 < f1/f4 < 0.8
(In the above 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,
A lens module satisfying the following conditional expression.
[Conditional Expression] f5/f6 > 0.8
(In the above conditional expression, f5 is the focal length [mm] of the fifth lens, and f6 is the focal length [mm] of the sixth lens)

Images