KR102009428B1 - 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 negative refractive power and having an inflection point formed on an image side surface thereof, and satisfying the following conditional expression.
[Condition Expression] 0.3 <SD / f <0.5
Where SD is the size of the aperture hole [mm] and f is the total focal length of the lens module [mm].

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 a camera to enable video call and picture taking. In addition, as the functions occupied by the camera in the portable terminal gradually increase, the demand for higher resolution and higher performance of the portable terminal camera is increasing.

However, since portable terminals are gradually miniaturized or lightweight, there are limitations in implementing a high resolution and high performance camera.

In order to solve this problem, recently, the lens of the camera is made of plastic material lighter than glass, and the lens module is composed of five or more lenses for high resolution.

However, plastic lenses are difficult to improve chromatic aberration compared to glass lenses, and it is difficult to realize relatively bright optical systems.

For reference, there are patent documents 1 to 4 as prior arts related to the present invention.

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

The present invention has been made to solve the above problems, and an object thereof is to provide a lens module that can implement high resolution.

Lens module according to an embodiment of the present invention for achieving the above object is 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 an inflection point formed on an image side surface thereof, and satisfying the following conditional expression.

Conditional Expression 0.36 <SD / f <0.48

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

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

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

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

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

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

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

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

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

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

[Condition Expression] 1.1 <TTL / f <1.4

In the above condition, 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.

[Condition Expression] V4-V5 <5.0

In the 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 condition, 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.

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

Conditional Expression SA <36

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

According to another aspect of the present invention, there is provided a lens module including a first lens having 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.

[Condition Expression] V5 <30

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

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

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

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

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

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

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

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

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

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

[Condition Expression] 1.1 <TTL / f <1.4

In the above condition, 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 another embodiment of the present invention may satisfy the following conditional expression.

[Condition Expression] V4-V5 <5.0

In the 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 condition, 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.

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

Conditional Expression SA <36

In the above condition, 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

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

The present invention can implement high resolution.

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

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In the following description of the present invention, terms that refer to the components of the present invention are named in consideration of the function of each component, it should not be understood as a meaning limiting the technical components of the present invention.

In addition, throughout the specification, the fact that a component is 'connected' to another component includes not only the case where these components are 'directly connected', but also when the components are 'indirectly connected' with other components therebetween. Means that. In addition, the term 'comprising' of an element means that the element may further include other elements, not to exclude other elements unless specifically stated otherwise.

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 the side closer to the object side in the lens module, the rear means the side closer to the image sensor in the lens module. In addition, in each lens, the first surface means a surface close to the object side (or an object side surface), and the second surface means a surface close to the image side (or an image side surface). In addition, in the present specification, the unit for the radius of curvature (Radius), thickness (Thickness), TTL, SL, IMGH, the total focal length of the optical system and the focal length of each lens are all 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 surface is convex, and the concave shape of one surface means that the optical axis portion of the surface is concave. Therefore, even if one surface of the lens is described as a convex shape, the edge portion of the lens may be concave. Similarly, even if one surface of the lens is described as a concave shape, the edge portion of the lens can be convex.

1 is a configuration diagram of a lens module according to an exemplary embodiment of the present disclosure, FIGS. 2 and 3 are curves illustrating aberration characteristics of the lens module illustrated in FIG. 1, and FIGS. 4 and 5 are illustrated in FIG. 1. 6 is a table illustrating characteristics of the lens module, and FIG. 6 is a configuration diagram of the lens module according to another exemplary embodiment of the present invention. FIGS. 7 and 8 are curves illustrating aberration characteristics of the lens module illustrated in FIG. And FIG. 10 is a table illustrating characteristics of the lens module illustrated in FIG. 6.

The lens module according to the present invention may include an optical system composed of six lenses. In 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 only composed of six lenses, but 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 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 lens 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 aspheric.

In addition, the optical system including the first to sixth lenses may have an F number 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 may clearly capture an image of a subject even under low light conditions (for example, 100 lux or less).

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

[Condition 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 of the optical system [mm].

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

[Condition 2] 1.1 <TTL / f <1.35

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

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

The optical system including the first to sixth lenses may satisfy Condition 3.

[Condition 3] V4-V5 <5.0

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

Here, the lens module satisfying the conditional expression 3 may be easily downsized.

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

[Condition 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 [mm] of the first surface of the first lens.

Here, the first lens that satisfies the conditional expression 4 may be easily manufactured in shape and may lower sensitivity according to manufacturing tolerances.

The optical system including the first to sixth lenses may satisfy Condition 5.

[Condition 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, lens reflection outside the upper limit of Conditional Expression 5 is likely to cause internal reflection.

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

[Condition 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 Condition 7.

[Condition 7] f5 / f6> 0.8

In condition 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 the first surface is convex and the second surface is concave. For example, the first lens may have a meniscus shape in which it is convex toward the object. At least one of the first and second surfaces of the first lens may be aspherical. 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 glass.

The second lens may have refractive power. For example, the second lens may have positive refractive power. Both surfaces of the second lens may be convex. At least one of the first and second surfaces of the second lens may be aspherical. 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 glass.

The third lens may have refractive power. For example, the third lens may have negative refractive power. Both surfaces of the third lens may be concave. 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 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 aspherical. 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 glass. In addition, the third lens may have a smaller diameter than the first lens and the second lens. For example, the effective diameter of the third lens (ie, the diameter of the portion where the effective light is 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 shape in which the first surface is concave and the second surface is convex. 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 and second surfaces of the fourth lens may be aspheric. 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 glass.

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 the first surface is concave and the second surface is convex. For example, the fifth lens may have a meniscus shape in which it is convex toward the image side. At least one of the first and second surfaces of the fifth lens may be aspherical. 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 glass.

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 the first surface is convex and the 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 of the first and second surfaces of the sixth lens may be aspherical. 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 glass.

Meanwhile, in the lens module according to the exemplary embodiments of the present disclosure, lenses may be disposed such that the effective diameter of the lens becomes smaller 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 may increase the amount of light projected onto the image sensor, thereby improving the resolution of the lens module.

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

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

In the present embodiment, the first lens 10 may have positive refractive power. In addition, the first lens 10 may have a shape in which the first surface is convex and the second surface is concave. The second lens 20 may have positive refractive power. In addition, both surfaces of the second lens 20 may be convex. The third lens 30 may have negative refractive power. In addition, the third lens 30 may have a shape in which the first surface is convex and the second surface is concave. The fourth lens 40 may have positive refractive power. In addition, the fourth lens 40 may have a shape in which the first surface is concave and the 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 the first surface is concave and the second surface is convex. The sixth lens 60 may have negative refractive power. In addition, the sixth lens 60 may have a shape in which the first surface is convex and the second surface is concave. 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 aperture stop ST may be disposed between the second lens 20 and the third lens 30. The first iris ST disposed as described above may perform the function of adjusting and vignetting the amount of light.

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

For example, A (1) of 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) may be calculated through FIG. 5. For example, the value corresponding to A (1) in FIG. 4 is the inverse 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 surface of the third lens 30 is 9.138 [mm], which is the inverse 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 surface of the fourth lens 40 is -6.155 [mm], which is the inverse 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 lens can be confirmed through FIG. 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] 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 refractive index of the second lens 20 is 1.544 and the Abbe number is 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 exemplary 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 exemplary embodiment may include the first lens 10, the second lens 20, the third lens 30, the fourth lens 40, the fifth lens 50, and the sixth lens ( The optical system includes a 60, and may further include an infrared cut filter 70 and an image sensor 80.

In the present embodiment, the first lens 10 may have positive refractive power. In addition, the first lens 10 may have a shape in which the first surface is convex and the second surface is concave. The second lens 20 may have positive refractive power. In addition, both surfaces of the second lens 20 may be convex. The third lens 30 may have negative refractive power. In addition, the third lens 30 may have a shape in which the first surface is convex and the second surface is concave. The fourth lens 40 may have positive refractive power. In addition, the fourth lens 40 may have a shape in which the first surface is concave and the 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 the first surface is concave and the second surface is convex. The sixth lens 60 may have negative refractive power. In addition, the sixth lens 60 may have a shape in which the first surface is convex and the second surface is concave. 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 aperture stop ST may be disposed between the second lens 20 and the third lens 30. The first iris ST disposed as described above may perform the function of adjusting and vignetting the amount of light.

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 a radius of curvature, thickness and distance of the lens, and FIG. 10 is a table showing 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) 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. For example, the radius of curvature A (3) of the side surface of the object of the second lens 20 is 2.302 [mm], which is the inverse 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 surface of the second lens 20 is -147.102 [mm], which is the inverse of -0.006798 corresponding to A (4) 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. 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 described above. 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.

Each of the embodiments configured as described above is somewhat different in some optical characteristics as shown in Table 1, but satisfies the conditional formulas 1 to 7 of the present invention.

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 be made without departing from the spirit of the technical idea of the present invention described in the claims below. Various changes may be made.

10 First Lens
20 Second Lens
30 Third Lens
40 Fourth Lens
50 Fifth Lens
60 6th Lens
70 infrared cut filter
80 image sensor

Claims (16)

A first lens having positive refractive power and having a convex shape on an object side and a concave shape on an image side;
A second lens having refractive power and having a convex shape on an object side;
A third lens having refractive power and having a convex shape on an object side;
A fourth lens having refractive power and having a concave shape on an object side and a convex shape on an image side;
A fifth lens having refractive power; And
A sixth lens having refractive power, the object side being convex, the image side concave, and an inflection point formed on the image side;
Including,
A lens module satisfying the following conditional formula.
[Conditional expression] | R2 | -| R1 | > 0
(In the above condition, R1 is the radius of curvature [mm] of the side of the object of the first lens, R2 is the radius of curvature [mm] of the image side of the first lens) The method of claim 1,
And the third lens has negative refractive power. The method of claim 1,
The lens module of claim 2, wherein the second lens is convex. The method of claim 1,
The third lens is a lens module of the image side concave shape. delete delete The method of claim 1,
The fifth lens has a concave shape of an object side. The method of claim 1,
The fifth lens has a convex shape of an image side surface. delete The method of claim 1,
The sixth lens has a negative refractive power. The method of claim 1,
The sixth lens has a shape in which an inflection point is formed on the side of the object. The method of claim 1,
A lens module satisfying the following conditional formula.
[Condition Expression] 1.1 <TTL / f <1.4
(In the above condition, 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 method of claim 1,
A lens module satisfying the following conditional formula.
[Condition Expression] V4-V5 <5.0 The method of claim 1,
A lens module satisfying the following conditional formula.
Conditional Expression SA <36
(In the above condition, SA is the sweep angle of the image side of the sixth lens.) The method of claim 1,
A lens module satisfying the following conditional formula.
Conditional Expression 0.36 <SD / f <0.48
(In the above condition, SD is the size of the aperture hole [mm] and f is the total focal length of the lens module [mm]). The method of claim 1,
And the fifth lens has negative refractive power.

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