KR102575218B1 - Lens module - Google Patents

Abstract

The lens module of the present invention includes 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 having a shape where an inflection point is formed on the 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 of the lens module [mm].

Description

Lens module

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

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

However, since portable terminals are gradually becoming smaller or lighter, there are limitations in implementing high-resolution and high-performance cameras.

To solve this problem, camera lenses are recently made of plastic, which is lighter than glass, and lens modules are made up of five or more lenses to achieve high resolution.

However, plastic lenses not only have difficulty improving chromatic aberration compared to glass lenses, but also make it difficult to implement a relatively bright optical system.

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

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

The present invention is intended to solve the above problems, and its purpose 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 positive refractive power; a second lens having positive refractive power; a third lens having refractive power; a fourth lens having positive refractive power; A fifth lens having refractive power; and a sixth lens having negative refractive power and having a shape where an inflection point is formed on the 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 of the lens module [mm].

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

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

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 where an inflection point is formed on the side of the object.

A lens module according to an embodiment of the present invention can satisfy the following conditional equation.

[Conditional expression] 1.1 < TTL/f < 1.4

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

A lens module according to an embodiment of the present invention can satisfy the following conditional equation.

[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 an embodiment of the present invention can satisfy the following conditional equation.

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

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

A lens module according to an embodiment of the present invention can satisfy the following conditional equation.

[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 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 equation.

[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 shape in which the object side is convex and the image side is convex.

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 where an inflection point is formed on the side of the object.

A lens module according to another embodiment of the present invention can satisfy the following conditional equation.

[Conditional expression] 1.1 < TTL/f < 1.4

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

A lens module according to another embodiment of the present invention can satisfy the following conditional equation.

[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 can satisfy the following conditional equation.

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

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

A lens module according to another embodiment of the present invention can satisfy the following conditional equation.

[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 can satisfy the following conditional equation.

[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 of the lens module [mm].

The present invention can implement high resolution.

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

Hereinafter, preferred embodiments of the present invention will be described in detail based on the attached illustration 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 should not be understood as limiting the technical components of the present invention.

In addition, throughout the specification, the fact that a certain configuration is 'connected' to another configuration includes not only cases where these configurations are 'directly connected', but also cases where they are 'indirectly connected' with another configuration in between. means that In addition, 'including' a certain component means that other components may be further included rather than excluding other components, unless specifically stated to the contrary.

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

Figure 1 is a configuration diagram of a lens module according to an embodiment of the present invention, Figures 2 and 3 are curves showing the aberration characteristics of the lens module shown in Figure 1, and Figures 4 and 5 are curves showing the aberration characteristics of the lens module shown in Figure 1. This is a table showing the characteristics of the lens module, Figure 6 is a configuration diagram of a lens module according to another embodiment of the present invention, Figures 7 and 8 are curves showing the aberration characteristics of the lens module shown in Figure 6, and Figure 9 and FIG. 10 is a table showing the 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 elaborate, the lens module may be composed of a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens. However, the lens module does not consist of only 6 lenses and may include other components as needed. For example, the lens module may include an aperture (stop) to adjust the amount of light. Additionally, the lens module may further include an infrared blocking filter to block infrared rays. Additionally, the lens module may further include an image sensor (i.e., an imaging device) for converting an image of a subject incident through an optical system into an electrical signal. Additionally, the lens module may further include a gap maintenance member for adjusting the distance between the lenses.

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

In addition, the optical system consisting of the first to sixth lenses may have an F No. of 2.4 or less. In this case, clear shooting of the subject may be possible. For example, the lens module according to the present invention can clearly photograph an image of a subject even in low-light conditions (for example, 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 Condition Equation 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 can satisfy Conditional Expression 2.

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

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

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

The optical system including the first to sixth lenses can satisfy conditional equation 3.

[Conditional Expression 3] V4 - V5 < 5.0

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

Here, a lens module that satisfies conditional equation 3 can be easily miniaturized.

The optical system including the first to sixth lenses can satisfy conditional equation 4.

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

In Conditional Equation 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 Conditional Equation 4 is easy to shape and can reduce sensitivity due to manufacturing tolerances.

The optical system including the first to sixth lenses can satisfy conditional equation 5.

[Conditional Expression 5] SA < 36

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

Here, conditional equation 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 equation 5 is prone to internal reflection.

The optical system including the first to sixth lenses can satisfy conditional equation 6.

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

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

The optical system including the first to sixth lenses can satisfy conditional equation 7.

[Conditional Expression 7] f5/f6 > 0.8

In Conditional Expression 7, f5 is the focal length [mm] of the 5th lens, and f6 is the focal length [mm] of the 6th 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 that 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 can be made of a material with high light transmittance and excellent processability. For example, the first lens may be made of 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. The second lens may have a shape where both sides are 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 can be made of a material with high light transmittance and excellent processability. For example, the second lens may be made of 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. The third lens may have a concave shape on both sides. 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 that is convex toward the object or a plano-convex shape that is convex toward the object. At least one of the first and second surfaces of the third lens may be aspherical. For example, both sides of the third lens may be aspherical. The third lens can be made of a material with high light transmittance and excellent processability. For example, the third lens may be made of plastic material. However, the material of the third lens is not limited to plastic. For example, the third lens may be made of glass. Additionally, the third lens may have a smaller diameter than the first and second lenses. For example, the effective diameter of the third lens (that is, the diameter of the portion where 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 concave first surface and a convex second surface. For example, the fourth lens may have a meniscus shape that is convex toward the image side or a plano-convex shape that is convex toward the image side. At least one of the first and second surfaces of the fourth lens may be aspherical. For example, both surfaces of the fourth lens may be aspherical. The fourth lens can be made of a material with high light transmittance and excellent processability. For example, the fourth lens may be made of 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 that 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 sides of the fifth lens may be aspherical. The fifth lens can be made of a material with high light transmittance and excellent processability. For example, the fifth lens may be made of 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 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 become convex toward the edge. At least one of the first and second surfaces of the sixth lens may be aspherical. For example, both sides of the sixth lens may be aspherical. The sixth lens can be made of a material with high light transmittance and excellent processability. For example, the sixth lens may be made of 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 attached embodiments, the lenses may be arranged so that the effective diameter of the lens becomes smaller as it moves from the first lens to the third lens, and then as it goes from the fourth lens to the sixth lens, the effective diameter of the lens becomes larger. . The optical system configured in this way can increase the amount of light projected to the image sensor, thereby improving the resolution of the lens module.

A lens module configured as above can improve aberrations that cause deterioration in image quality. In addition, a lens module configured as above can improve resolution. In addition, the lens module configured as above can be advantageous in easily reducing the weight and lowering the production 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 this 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-off filter 70 and an image sensor 80.

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

The lens module 100 according to this embodiment may include one or more apertures (ST). For example, the aperture ST may be disposed between the second lens 20 and the third lens 30. The first aperture (ST) arranged in this way can control the amount of light and perform vignetting functions.

A lens module configured in this way may have the aberration characteristics shown in FIGS. 2 and 3 and the lens characteristics shown in FIGS. 4 and 5. For reference, Figure 4 is a table showing the radius of curvature, thickness, and distance of the lens, and Figure 5 is a table showing the aspheric value of the lens.

For example, A(1) in FIG. 4 represents the radius of curvature of the object side of the first lens, and A(2) in FIG. 4 represents the radius of curvature of the image side of the first lens. Here, the values of A(1), A(2), and A(i) can be calculated through FIG. 5. For example, the value corresponding to A(1) in FIG. 4 is the reciprocal of the value corresponding to A(1) on the vertical axis and CURV on the horizontal axis in FIG. 5. For example, the radius of curvature (A(5)) of the object side 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 lenses can be confirmed through Figure 4. For example, the thickness of the first lens 10 is 0.49 [mm], corresponding to the thickness/distance of 1 on the vertical axis and the horizontal axis in Figure 4, and the distance between the first lens 10 and the second lens 20 is as above. The value listed below is 0.0995[mm].

In addition, the refractive index and Abbe number of each lens can be confirmed through the GLA value in Figure 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 embodiment of the present invention will be described with reference to FIGS. 6, 7, 8, 9, and 10.

The lens module 100 according to this 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-off filter 70 and an image sensor 80.

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

The lens module 100 according to this embodiment may include one or more apertures (ST). For example, the aperture ST may be disposed between the second lens 20 and the third lens 30. The first aperture (ST) arranged in this way can control the amount of light and perform vignetting functions.

A lens module configured in this way may have the aberration characteristics shown in FIGS. 7 and 8 and the lens characteristics shown in FIGS. 9 and 10. For reference, Figure 9 is a table showing the radius of curvature, thickness, and distance of the lens, and Figure 10 is a table showing the aspheric value of the lens.

For example, A(3) in FIG. 9 represents the radius of curvature of the object side of the second lens, and A(4) in FIG. 9 represents the radius of curvature of the image side of the second lens. Here, the values of A(1), A(2), and A(i) can be calculated through FIG. 10. For example, the value corresponding to A(3) in FIG. 9 is the reciprocal of the value corresponding to A(3) on the vertical axis and CURV on the horizontal axis in FIG. 10. For example, the radius of curvature (A(3)) of the 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 lenses can be confirmed through Figure 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 Figure 9, and the distance between the third lens 30 and the fourth lens 40 is as above. The value listed below is 0.45 [mm].

In addition, the refractive index and Abbe number of each lens can be confirmed through the GLA value in Figure 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 constructed as above has some differences in some optical characteristics as shown in Table 1, but all satisfy conditional equations 1 to 7 of the present invention.

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 can make any changes without departing from the gist of the technical idea of the present invention as set forth in the following claims. It can be implemented with various changes.

10 First lens
20 Second lens
30 Third lens
40 4th lens
50 5th lens
60 6th lens
70 Infrared blocking filter
80 image sensor

Claims (12)

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