KR20210033455A - Lens module - Google Patents

Abstract

According to the present invention, a lens module comprises: a first lens having positive refractive power; a second lens having the positive refractive power; a third lens having the refractive power; a fourth lens having the positive refractive power; a fifth lens having the refractive power; and a sixth lens having negative refractive power and having a shape where an inflection point is formed on an upper surface. The lens module can satisfy a following conditional expression. In the conditional expression that 0.3 < SD/f < 0.5, SD (mm) is a size of an aperture hole and f (mm) is an overall focal distance of the lens module. The lens module can realize high resolution.

Description

Lens module

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

Recently, portable terminals are equipped with cameras to enable video calls and photographs. In addition, as functions occupied by cameras in portable terminals are gradually increasing, demands for high resolution and high performance of cameras for portable terminals are gradually increasing.

However, since portable terminals are gradually miniaturized or lightened, there is a limit to implementing 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 that of glass, and a lens module is composed of five or more lenses to realize high resolution.

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

For reference, there are Patent Documents 1 to 4 as prior art related to the present invention.

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 thereof 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 comprises: 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 an inflection point formed on an image side thereof, 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 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 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 surface, 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 number of the fourth lens, and V5 is the Abbe 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 surface of the first lens [mm], and R2 is the radius of curvature of the image side surface 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 comprises: 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 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 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 [mm] from the object side of the first lens to the image surface, and f is the total focal length [mm] of the lens module.

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 number of the fourth lens, and V5 is the Abbe 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 of the object side surface of the first lens [mm], and R2 is the radius of curvature of the image side surface of the first lens [mm].

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

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 the characteristics of the lens module shown in FIG. 6.

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

In the following description of the present invention, terms referring to the constituent elements of the present invention are named in consideration of the functions of the respective constituent elements, and thus, should not be understood as limiting the technical constituents of the present invention.

In addition, throughout the specification, that a certain configuration is'connected' to another configuration includes not only the case where these configurations are'directly connected', but also the case where the other configurations are'indirectly connected'. 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 the lens closest to the object side, and the sixth lens means the lens closest to the image side. Further, the front means the side closer to the object side of the lens module, and the rear side means the side closer to the image sensor of 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, units for the radius of curvature (Radius), thickness, TTL, SL, IMGH of the lens, the total focal length of the optical system, and the focal length of each lens are all in the unit of mm. In addition, in the description of the shape of the lens, the meaning of a convex shape on one side means that the optical axis portion of the surface is convex, and the meaning of the concave shape on the surface means that the optical axis portion of the corresponding surface is concave. Therefore, even if it is described that one surface of the lens is convex, the edge portion of the lens may be concave. Similarly, even if it is described that one surface of the lens is concave, 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 A table showing the 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 six lenses. To further explain, 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 an image of a subject incident through the optical system into an electric signal. In addition, the lens module may further include a gap maintaining member for adjusting a 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. In addition, 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 clearly capture an image of a subject 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 aperture hole [mm], and f is the total focal length [mm] of the optical system.

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

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

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

Here, it is difficult to secure optical performance of a lens module that exceeds the lower limit of Conditional Equation 2, and it may be difficult to miniaturize a lens module that exceeds the upper limit of Conditional Equation 2.

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

[Conditional Expression 3] V4-V5 <5.0

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

Here, the lens module that satisfies the conditional expression 3 may 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 of the second surface of the first lens [mm], and R1 is the radius of curvature of the first surface of the first lens [mm].

Here, the first lens that satisfies the conditional expression (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 Equation 5.

[Conditional Expression 5] SA <36

In Conditional Expression 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 that exceeds the upper limit of Conditional Expression 5 is liable to generate 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 Condition 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 convex first surface and a concave second surface. For example, the first lens may have a meniscus shape convex toward the object side. At least one of the first and second surfaces 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 processability. 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. Both sides of the second lens may have a convex shape. At least one of the first and second surfaces 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 processability. 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. Both surfaces of the third lens may have a concave shape. 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 side or a plano-convex shape convex toward the object side. At least one of the first and second surfaces 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 processability. 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 diameter smaller than that of the first lens and the second lens. For example, an effective diameter of the third lens (ie, a diameter of a portion where 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 an image side or a plano-convex shape convex toward an image side. At least one of the first and second surfaces 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 processability. 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 side. At least one of the first and second surfaces 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 processability. 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 and second surfaces 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 processability. 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, 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 aberration that causes image quality deterioration. In addition, the lens module configured as described above can improve the resolution. In addition, the lens module configured as described above can 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. An optical system composed of 60) may be included, and an infrared cut filter 70 and an image sensor 80 may be further included.

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 concave first surface and a convex second surface. The fifth lens 50 may have 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 negative refractive power. In addition, the sixth lens 60 may have a convex first surface and a concave second surface. In addition, 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 stop ST may be disposed between the second lens 20 and the third lens 30. The first aperture ST arranged in this way may perform functions of adjusting the amount of light and performing vignetting.

The lens module configured as described above may have aberration characteristics illustrated in FIGS. 2 and 3 and may have lens characteristics illustrated 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 aspherical surface values of the lens.

For example, A(1) of FIG. 4 indicates the radius of curvature of the object side of the first lens, and A(2) of FIG. 4 indicates 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, a value corresponding to A(1) in FIG. 4 is an reciprocal 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 object side of the third lens 30 is 9.138 [mm], which is an 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 an inverse of -0.162472 corresponding to A(8) of the vertical axis and CURV of 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 the thickness/distance of the vertical axis 1 and the horizontal axis in FIG. 4, and the distance between the first lens 10 and the second lens 20 is It is 0.0995 [mm] listed at the bottom of 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 refractive index of the second lens 20 is 1.544, and the Abbe number is 56.0. As another example, the third lens 30 has a refractive index of 1.639 and an Abbe number of 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. An optical system composed of 60) may be included, and an infrared cut filter 70 and an image sensor 80 may be further included.

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 concave first surface and a convex second surface. The fifth lens 50 may have 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 negative refractive power. In addition, the sixth lens 60 may have a convex first surface and a concave second surface. In addition, 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 stop ST may be disposed between the second lens 20 and the third lens 30. The first aperture ST arranged in this way may perform functions of adjusting the amount of light and performing vignetting.

The lens module configured as described above may have aberration characteristics shown in FIGS. 7 and 8, and may have lens characteristics illustrated 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 aspherical surface values of the lens.

For example, A(3) of 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, a value corresponding to A(3) in FIG. 9 is an reciprocal of a 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 an 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 an inverse of -0.006798 corresponding to A(4) of the vertical axis and CURV of 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 the vertical axis 3 and the horizontal axis in FIG. 9, and the distance between the third lens 30 and the fourth lens 40 is It is 0.45 [mm] listed at the bottom of 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 fifth lens 50 has a refractive index of 1.639 and an Abbe number of 23.0.

Each of the embodiments configured as described above is somewhat different in some optical properties as shown in Table 1, but all of the conditional expressions 1 to 7 of the present invention are satisfied.

The present invention is not limited to the embodiments described above, and those of ordinary skill in the technical field to which the present invention pertains, within the scope not departing from the gist of the technical idea of the present invention described in the following claims. It will be possible to implement various changes.

10 first lens
20 second lens
30 third lens
40 fourth lens
50 fifth lens
60 sixth lens
70 infrared cut filter
80 image sensor

Claims (14)

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

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