KR20170058601A - Image pickup lens, camera module and digital device including the same - Google Patents

Abstract

The present invention relates to an image lens, and a camera module and a digital device including the same. An embodiment of the present invention includes a first lens group including a first lens to a third lens disposed sequentially in order from a subject side to an image side direction, and a second lens group including a fourth lens to a sixth lens. According to the present invention, the first lens and the second lens have a negative refractive power, the third lens has a positive refractive power, the fourth lens has a positive refractive power, the fifth lens has a negative refractive power, and the sixth lens has a positive refractive power, wherein a radius curvature of a subject surface of the third lens is larger than 3.1 and smaller than 4.4.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an image pickup lens, a camera module including the same,

An embodiment relates to an imaging lens.

2. Description of the Related Art In general, an optical system employed in a vehicle camera or a surveillance camera requires a wide-angle lens having a wide viewing angle with a horizontal viewing angle of at least a certain angle in order to photograph a wide range of images such as front, Has been required to be smaller and lighter.

In this trend, the miniaturization of the light receiving element such as a CCD (Charge Coupled Device) mounted on the miniaturized image pickup apparatus is progressing, but the portion occupying the largest volume in the image pickup apparatus is the image pickup lens section.

Therefore, a component that is the most important issue in downsizing and thinning of the image pickup apparatus is an image pickup lens that forms an image of the object.

However, in the case of implementing an optical system having a wide angle of view, the length of the optical system in the direction of the optical axis has become long and the diameter of the lens has to be made large in order to secure the amount of ambient light.

The embodiment intends to provide an imaging lens having a high-performance and ultra-thin size.

The embodiment includes a first lens group including a first lens to a third lens sequentially arranged from the object side in the image forming side direction and a second lens group including the fourth lens to the sixth lens, Wherein the first lens has positive refractive power and the third lens has positive refractive power, the fourth lens has positive refractive power, the fifth lens has negative refractive power, and the sixth lens has negative refractive power, And has a positive refracting power and a radius of curvature of the object surface of the third lens is larger than 3.1 and smaller than 4.4.

For example, the first lens and the second lens may have the shape of a meniscus convex to the object side.

The radius of curvature of the imaging plane of the third lens may be greater than -8.0 and less than -4.0.

For example, it may further include a diaphragm disposed between the third lens and the fourth lens.

For example, the diaphragm and the fourth lens may be disposed at a distance of 25 mu m to 70 mu m.

For example, at least one of the first lens and the sixth lens may be made of glass.

For example, the shape of the object surface of the fifth lens may be formed corresponding to the shape of the image-forming surface of the fourth lens.

For example, the shape of the object surface of the sixth lens may be formed corresponding to the shape of the imaging surface of the fifth lens.

Another embodiment is an imaging lens comprising the above-described imaging lens; A filter that selectively transmits light passing through the imaging lens according to a wavelength; And a light receiving element for receiving the light transmitted through the filter.

Yet another embodiment provides a digital device including the camera module described above.

The imaging lens according to the embodiment can be miniaturized by reducing the total length of the imaging lens while having a wide angle of view with six lenses and realizing a low distortion image.

1 is a view showing a first embodiment of an imaging lens.
2 is a view showing a second embodiment of the imaging lens.
3 is a view showing a third embodiment of the imaging lens.
4 is a graph showing aberration diagrams of the first embodiment of the imaging lens, and is a graph showing longitudinal spherical aberration, astigmatic field curves, and distortion in order from the left.
5 is a graph showing the aberration diagram of the second embodiment of the imaging lens, and is a graph showing longitudinal spherical aberration, astigmatic field curves, and distortion in order from the left.
FIG. 6 is a graph showing aberration diagrams of the third embodiment of the imaging lens, and is a graph showing the number of spherical centers, astigmatism, and distortion aberration in order from the left.
7 is a view showing a fourth embodiment of the imaging lens.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG.

In the description of the embodiment according to the present invention, the term 'object surface' means a surface of a lens facing the object side with respect to the optical axis, and the term 'imaging surface' Means a surface of the lens facing the image side.

Further, in the present invention, "+ power" of the lens represents a converging lens for converging parallel light, and "-Power" of the lens represents a diverging lens for emitting parallel light.

Fig. 1 is a view showing a first embodiment of an imaging lens, Fig. 2 is a view showing a second embodiment of the imaging lens, and Fig. 3 is a view showing a third embodiment of the imaging lens.

1 to 3, the first to third embodiments of the imaging lens include a first lens 110 including a first lens 110 to a third lens 130 arranged in order from the object side to the imaging side, And a second lens group II including a fourth lens 140 to a sixth lens 160. The second lens group II includes,

A shutter may be included on the front surface of the first lens 110 and a shutter may be provided between the third lens 130 of the first lens group I and the fourth lens 140 of the second lens group II The diaphragm AS may be a variable diaphragm.

The filter 170 and the light receiving element 180 may be included in order to form an imaging lens in the camera module and a cover glass may be included between the filter 170 and the light receiving element 180 .

In this case, the filter 170 is provided with a flat optical member such as an infrared ray filter, and the light receiving element 180 is an image sensor that is stacked on a printed circuit board (not shown) have.

The above-described embodiment and the following embodiments can provide an imaging lens that can be applied to a camera module having a large number of pixels and / or a large number of pixels, and the above-described camera module includes an image sensor or a light receiving element having a large number of pixels and / can do.

1 to 3, 'S11' is a target surface of the first lens 110, 'S12' is an image forming surface of the first lens 110, 'S21' is a target surface of the second lens 120, 'S22' is an image forming surface of the third lens 130, 'S22' is an image forming surface of the second lens 120, 'S31' is a target surface of the third lens 130, and 'S32' S51 is an object surface of the fifth lens 150, and S52 is an object surface of the fourth lens 140. [ 5 'is an image forming surface of the sixth lens 160,' S61 'is an image surface of the sixth lens 160, and' S62 'is an image forming surface of the sixth lens 160.

The first lens 110 and the second lens 120 of the first lens group I may be in the form of a meniscus convex to the object side. The first lens 110 and the second lens 120 120 are convex on the object surfaces S11, S21 and can have a negative refractive power. The third lens 130 is configured such that both the object plane S31 and the imaging plane S32 are convex, the object plane S31 is convex and the imaging plane S32 is flat or concave, and the positive refractive power Lt; / RTI >

Further, in the second lens group II, the fourth lens 140 is configured such that both the object surface S41 and the imaging surface S42 are convex, the object surface S41 is convex and the imaging surface S42 is flat or concave And can have a positive refractive power. The fifth lens 150 is configured such that both the object surface S51 and the imaging surface S52 are concave or the object surface S51 is flat or concave and the imaging surface S52 is convex and has a negative refractive power have. The sixth lens 160 is configured such that both the object surface S61 and the imaging surface S62 are concave or the object surface S61 is concave and the imaging surface S62 is flat or convex, .

At least one of the first lens 110 to the sixth lens 160 may be made of glass. In embodiments, the first lens 110 and the third lens 130 may be glass lenses . Here, the object surface S11 of the first lens 110 may be arranged to be convex toward the object side and exposed to the external environment. If the first lens 110 is provided as a glass lens, It is possible to prevent scratches or the like from being generated on the surface of the object surface S11 of the first lens 110. [

The outer diameter B of the second lens 120 may be equal to or smaller than the inner diameter A of the image forming surface S12 of the first lens 110. [ In this structure, light transmitted through the first lens 110 is incident on the object surface S21 of the second lens 120, and light transmitted through the second lens 120 is incident on the third lens (130).

The third lens 130 may be smaller in diameter than the second lens 120 and the diaphragm AS may be disposed between the third lens 130 and the fourth lens 140 The distance d7 from the object surface S41 of the fourth lens 140 to the diaphragm AS is smaller than the distance d6 from the imaging surface S31 of the third lens 130 to the diaphragm AS Can be small.

Here, the distance d7 from the diaphragm AS to the object surface S41 of the fourth lens 140 may be 25 mu m to 70 mu m.

The shape of the object surface S51 of the fifth lens 150 may be formed corresponding to the shape of the image forming surface S42 of the fourth lens 140 and the image forming surface S52 of the fifth lens 150 The shape of the object surface S61 of the sixth lens 160 can be formed.

That is, when the imaging surface S42 of the fourth lens 140 is convexly formed, the object surface S51 of the fifth lens 150 may be concave and the imaging surface S42 of the fourth lens 140 Is concave, the object surface S51 of the fifth lens 150 may be convexly formed. When the imaging surface S52 of the fifth lens 150 is convexly formed, the object surface S61 of the sixth lens 160 may be concave and the imaging surface S52 of the fifth lens 150 Is concave, the object surface S61 of the sixth lens 160 may be convexly formed.

As described above, the structure in which the fourth lens 140 to the sixth lens 160 are disposed can increase the low dispersion performance, thereby minimizing the aberration. The imaging lens having six lenses The overall length of the imaging lens can be reduced, and the imaging lens can be miniaturized.

On the other hand, at least one surface of the lenses of the first to sixth lenses 110 to 160 may be an aspherical surface. When at least one surface of the lenses is formed as an aspherical surface, various aberrations such as spherical aberration, It is possible to excellently correct the aberrations and the like.

In addition, at least one of the first to sixth lenses 110 to 160 may be made of glass. In embodiments, the first lens 110 and the third lens 130 may be glass lenses. Since the glass lens has a relatively high transition point, deformation of the refractive index and deformation of the focal length can be minimized even with a change over time due to temperature change. In the embodiment, the third lens 130 is most affected by heat, The optical performance of the imaging lens can be greatly improved.

Although all of the first to sixth lenses 110 to 160 may be made of glass, if the lens is made only of glass, the manufacturing cost of the imaging lens is increased. As described above, when the first lens and the third lens are made of glass and the other lens is made of a plastic material, it is possible to prevent the lens from being damaged by an impact caused by the external environment, The cost for manufacturing the imaging lens can be greatly reduced.

The lens according to the embodiments may be coated with the surface of the lens to prevent reflection or improve surface hardness.

On the other hand, in the first to third embodiments, the radius of curvature of the object surface S31 of the third lens 130 may be larger than 3.1 and smaller than 4.4. The radius of curvature of the imaging plane S32 of the third lens 130 may be larger than -8.0 and smaller than -4.0.

Table 1 shows the radius of curvature, thickness or distance, refractive index, and Abbe number of each lens in the first embodiment of the imaging lens.

Face number The radius of curvature (R) Thickness or distance (d) Refractive index (Nd) Abbe number (Vd) S11 14.69675 0.75 1.62 60.3 S12 3.241432 1.240769 S21 2.62929 0.975386 1.5311 56.5 S22 0.70966 1.353355 S31 3.237566 1.235834 1.804 46.5 S32 -7.55 0.799219 AS (stop) Inf. 0.067433 S41 1.8783 1.186964 1.5311 56.5 S42 -0.9538 0.030529 S51 -1.65065 0.385577 1.651 21.5 S52 2.8018 0.1487 S61 4.15 1.078627 1.5311 56.5 S62 -4.509402 0.359275

In Table 1, the curvatures of the object surface and the image plane of the first lens 110 to the third lens 130, the diaphragm AS and the fourth lens 140 to the sixth lens 160 are described in order. Is positive when the light is deflected toward the object side, and when it is negative (-), it is deflected toward the light receiving element. And is flat when the curvature is Infinity. The thickness is described in correspondence with each object plane, and the distance from the adjacent lens or the like corresponding to the image plane is described.

1, the distance d6 between the imaging surface S32 of the third lens 130 and the diaphragm AS is 0.799219 mm and the diaphragm AS and the object surface S41 of the fourth lens 140, (D7) is 0.067433 mm, which is smaller than d6 by d7. That is, the fourth lens 140 may be disposed closer to the diaphragm AS than the third lens 130. In this structure, the diaphragm AS disposed between the third lens 130 and the fourth lens 140 controls the optical path to enter the fourth lens 140 having a diameter smaller than that of the third lens 130, It is possible to effectively transmit the light.

The distance d9 between the imaging surface S42 of the fourth lens 140 and the object surface S51 of the fifth lens 150 and the distance d9 between the imaging surface S52 of the fifth lens 150, And the distance d10 from the object plane S61 of the lens 160 are 0.030529 mm and 0.1487 mm, respectively, and the distances between the lenses are very close to each other. When the distance between the respective lenses is arranged close to each other, the low dispersion performance can be increased to minimize the aberration, and the entire length of the imaging lens provided with the plurality of lenses can be minimized to realize the smallest imaging lens.

In the first embodiment, the refractive power of the first lens 110 is -0.145, the refractive power of the second lens 120 is -0.450, and the refractive power of the third lens 130 is 0.337. The refractive power of the fourth lens 140 is 0.718, the refractive power of the fifth lens 150 is -0.648, and the refractive power of the sixth lens 160 is 0.235.

The focal length of the first lens 110 is -6.875, the focal length of the second lens 120 is -2.222, and the focal length of the third lens 130 is 2.969. In addition, the focal length of the fourth lens 140 is 1.394, the focal length of the fifth lens 150 is -1.543, and the focal length of the sixth lens 160 is 4.252. Here, when the focal length is positive, it means true focus, and when it is negative, it means a focal point, which is the same in the following embodiments.

The total focal length of the imaging lens according to the first embodiment is 1.13 mm.

Although not shown, each lens can be coated on the surface for anti-reflection or surface hardness enhancement.

Table 2 shows the conic constant (k) and the aspherical surface coefficients (A to G) of each lens surface in the first embodiment.

S21 S22 S41 S42 S51 S52 S61 S62 K -0.4031 -0.964468 1.086765 -0.414876 -12.791772 3.687516 2.352646 -6.266834 A -.252E-01 0.661389E-02 -.274578E-01 0.203026E + 00 -.612699E + 00 -.306226E + 00 0.109905E-01 0.116186E + 00 B -.107536E-02 -.267704E-01 -.289468E-01 -.662103E + 00 0.369628E + 00 0.258669E + 00 -.135289E + 00 -.595542E-01 C 0.357990E-03 0.912288E-02 0.727915E-01 0.938484E + 00 -.292290E + 00 -.105556E + 00 0.113930E + 00 0.456584E-02 D -.303688E-04 -.233290E-02 -.464107E + 00 -.626468E + 00 -.162009E-02 0.116281E-01 -.350098E-01 0.363629E-02 E 0.313416E-03 0.397748E-05 -.862828E-05 0.971354E-06 -.177416E-04 0.998387E-03 -.847247E-03 F -.491140E-05 0.440586E-05 G 0.223016E-06 -.669595E-06

And the lenses of the second lens 120, the fourth lens to the sixth lens 140 to 160 are formed aspheric surfaces. If both surfaces of the lenses of the second lens 120 and the fourth lens to the sixth lens 140 to 160 are formed as aspherical surfaces, it is possible to improve various aberrations such as spherical aberration, coma aberration and distortion aberration .

FIG. 4 is a graph showing aberration diagrams of the first embodiment of the imaging lens, and is a graph showing longitudinal spherical aberration, astigmatic field curves, and distortion in order from the left.

In FIG. 4, the Y axis means the size of the image, the X axis means the focal length (in mm) and the distortion degree (in%), and the closer the curves are to the Y axis, the better the aberration correction function. 4 is a graph showing the relationship between the wavelengths of 435.80 nm, 486.13 nm, 546.07 nm, 587.56 nm and 656.28 nm, and the graph relating to astigmatism shows a spectrum of light having a wavelength of 587.56 nm (S: Sagittal surface) and a meridional surface (T: tangential surface). Also, the graph relating to the distortion aberration shows a distortion with respect to light having a wavelength of 587.56 nm.

Table 3 shows the radius of curvature, thickness or distance, refractive index and Abbe number of the second embodiment of the imaging lens.

Face number The radius of curvature (R) Thickness or distance (d) Refractive index (Nd) Abbe number (Vd) S11 11.94361 0.65 1.773 49.6 S12 2.82062 0.92924 S21 1.89687 0.6913 1.5311 56.5 S22 0.68825 1.32549 S31 4.36875 1.876451 1.804 46.5 S32 -4.368752 0.75875 AS (stop) Inf. 0.03 S41 1.7732 1.15244 1.5311 56.5 S42 -0.85067 0.05 S51 -1.17077 0.327647 1.651 21.5 S52 3.82743 0.23394 S61 -18.346 1.37266 1.5311 56.5 S62 -1.87429 0.359297

In Table 3, the curvatures of the object surface and the imaging surface of the first lens 110 to the third lens 130, the diaphragm AS and the fourth lens 140 to the sixth lens 160 are described in order, Is positive when the light is deflected toward the object side, and when it is negative (-), it is deflected toward the light receiving element. And is flat when the curvature is Infinity. The thickness is described in correspondence with each object plane, and the distance from the adjacent lens or the like corresponding to the image plane is described.

2, the distance d6 between the imaging surface S32 of the third lens 130 and the diaphragm AS is 0.75875 mm, and the distance between the diaphragm AS and the object surface S41 of the fourth lens 140, The distance d7 between the electrodes is 0.03 mm, which may be smaller than d6 by d7. That is, the fourth lens 140 may be disposed closer to the diaphragm AS than the third lens 130. In this structure, the diaphragm AS disposed between the third lens 130 and the fourth lens 140 controls the optical path to enter the fourth lens 140 having a diameter smaller than that of the third lens 130, It is possible to effectively transmit the light.

The distance d9 between the imaging surface S42 of the fourth lens 140 and the object surface S51 of the fifth lens 150 and the distance d9 between the imaging surface S52 of the fifth lens 150, And the distance d10 from the target surface S61 of the lens 160 are 0.05 mm and 0.2 mm, respectively, so that the distance between the lenses is very close to each other. When the distance between the respective lenses is arranged close to each other, the low dispersion performance can be increased to minimize the aberration, and the entire length of the imaging lens provided with the plurality of lenses can be minimized to realize the smallest imaging lens.

In the second embodiment, the refractive power of the first lens 110 is -0.203, the refractive power of the second lens 120 is -0.394, and the refractive power of the third lens 130 is 0.333. The refractive power of the fourth lens 140 is 0.783, the refractive power of the fifth lens 150 is -0.745, and the refractive power of the sixth lens 160 is 0.262.

The focal length of the first lens 110 is -4.933, the focal length of the second lens 120 is -2.537, and the focal length of the third lens 130 is 3.004. Further, the focal length of the fourth lens 140 is 1.277, the focal length of the fifth lens 150 is -1.342, and the focal length of the sixth lens 160 is 3.820.

The total focal length of the imaging lens according to the second embodiment is 1.13 mm.

Although not shown, each lens can be coated on the surface for anti-reflection or surface hardness enhancement.

Table 4 shows the conic constant (k) and the aspheric coefficient (A to G) of each lens surface in the second embodiment.

S21 S22 S41 S42 S51 S52 S61 S62 K -0.839052 -0.983585 0.709736 -1.410105 -6.508066 3.943179 -5.000000 -7.414282 A -.382334E-01 -.578321E-03 -.272670E-02 0.375670E + 00 -.394247E + 00 -.149821E + 00 0.174420E + 00 0.942457E-01 B -.874743E-03 -.127270E-01 -.458143E-03 -.817933E + 00 0.438872E + 00 0.210567E + 00 -.276956E + 00 -.322011E-01 C 0.504106E-03 0.268067E-02 -.806335E-02 0.396670E + 00 -.102255E + 01 -.147199E + 00 0.202293E + 00 -.700608E-02 D -.388921E-04 -.166510E-02 -.275423E + 00 -.238163E + 00 0.391783E + 00 0.463373E-01 -.675696E-01 0.515609E-02 E 0.697806E-06 0.313416E-03 0.397748E-05 -.862828E-05 0.971354E-06 -.177416E-04 0.998387E-03 -.847247E-03 F -.491140E-05 0.440586E-05 G 0.223016E-06 -.669595E-06

And the lenses of the second lens 120, the fourth lens to the sixth lens 140 to 160 are formed aspheric surfaces. If both surfaces of the lenses of the second lens 120 and the fourth lens to the sixth lens 140 to 160 are formed as aspherical surfaces, it is possible to improve various aberrations such as spherical aberration, coma aberration and distortion aberration .

5 is a graph showing the aberration diagram of the second embodiment of the imaging lens, and is a graph showing longitudinal spherical aberration, astigmatic field curves, and distortion in order from the left.

5, the Y axis means the size of the image, the X axis means the focal length (in mm) and the distortion degree (in%), and the closer the curves approach the Y axis, the better the aberration correction function. The graphs relating to the number of centroids in FIG. 5 show the difference in the center-of-curvature for light with wavelengths of 435.80 nm, 486.13 nm, 546.07 nm, 587.56 nm and 656.28 nm, and the graph regarding astigmatism shows that the light with a wavelength of 587.56 nm (S: Sagittal surface) and a meridional surface (T: Tangential surface). Also, the graph relating to the distortion aberration shows a distortion with respect to light having a wavelength of 587.56 nm.

Table 5 shows the radius of curvature, thickness or distance, refractive index, and Abbe number of each lens in the third embodiment of the imaging lens.

Face number The radius of curvature (R) Thickness or distance (d) Refractive index (Nd) Abbe number (Vd) S11 13.71309 0.75 1.62 60.3 S12 3.241247 0.914072 S21 1.881089 0.862152 1.5311 56.5 S22 0.651857 1.775968 S31 3.848526 1.154678 1.804 46.5 S32 -7.1103 0.75877 AS (stop) Inf. 0.055473 S41 1.980489 1.066256 1.5311 56.5 S42 -0.99073 0.124355 S51 -1.05453 0.385117 1.651 21.5 S52 5.84146 0.073027 S61 3.235729 1.269664 1.5311 56.5 S62 -2.52069 0.359275

In Table 5, the curvatures of the object surface and the imaging surface of the first lens 110 to the third lens 130, the diaphragm AS, and the fourth lens 140 to the sixth lens 160 are described in order, Is positive when the light is deflected toward the object side, and when it is negative (-), it is deflected toward the light receiving element. And is flat when the curvature is Infinity. The thickness is described in correspondence with each object plane, and the distance from the adjacent lens or the like corresponding to the image plane is described.

3, the distance d6 between the imaging surface S32 of the third lens 130 and the diaphragm AS is 0.75877 mm, and the distance between the diaphragm AS and the object surface S41 of the fourth lens 140, (D7) is 0.055473 mm, which is smaller than d6 by d7. That is, the fourth lens 140 may be disposed closer to the diaphragm AS than the third lens 130. In this structure, the diaphragm AS disposed between the third lens 130 and the fourth lens 140 controls the optical path to enter the fourth lens 140 having a diameter smaller than that of the third lens 130, It is possible to effectively transmit the light.

The distance d9 between the imaging surface S42 of the fourth lens 140 and the object surface S51 of the fifth lens 150 and the distance d9 between the imaging surface S52 of the fifth lens 150, And the distance d10 from the object plane S61 of the lens 160 are 0.124355 mm and 0.073027 mm, respectively, so that the distance between the lenses is very close to each other. When the distance between the respective lenses is arranged close to each other, the low dispersion performance can be increased to minimize the aberration, and the entire length of the imaging lens provided with the plurality of lenses can be minimized to realize the smallest imaging lens.

In the third embodiment, the refractive power of the first lens 110 is -0.142, the refractive power of the second lens 120 is -0.403, and the refractive power of the third lens 130 is 0.307. The refractive power of the fourth lens 140 is 0.704, the refractive power of the fifth lens 150 is -0.745, and the refractive power of the sixth lens 160 is 0.346.

The focal length of the first lens 110 is -7.034, the focal length of the second lens 120 is -2.482, and the focal length of the third lens 130 is 3.258. Further, the focal length of the fourth lens 140 is 1.420, the focal length of the fifth lens 150 is -1.343, and the focal length of the sixth lens 160 is 2.889.

The total focal length of the imaging lens according to the third embodiment is 1.13 mm.

Although not shown, each lens can be coated on the surface for anti-reflection or surface hardness enhancement.

Table 6 shows the conic constant (k) and the aspheric coefficient (A to G) of each lens surface in the third embodiment.

S21 S22 S41 S42 S51 S52 S61 S62 K -1.062053 -0.965370 1.335112 -0.455120 -4.580216 18.559390 -3.442983 -20.000000 A -.253616E-01 -.171744E-01 -.323602E-01 0.248580E + 00 -.335587E + 00 -.125987E + 00 -.451429E-01 0.658127E-01 B -.855337E-03 0.647627E-02 -.323658E-01 -.633501E + 00 0.368719E-01 0.786274E-01 -.246257E-01 -.224058E-01 C 0.355333E-03 -.438617E-02 -.226234E-01 0.375419E + 00 -.548056E + 00 0.375388E-03 0.418744E-01 -.769964E-02 D -.267182E-04 -.339657E-03 -.725662E + 00 -.288746E + 00 0.228853E + 00 -.112482E-01 -.171721E-01 0.516394E-02 E 0.697806E-06 0.313416E-03 0.397748E-05 -.862828E-05 0.971354E-06 -.177416E-04 0.998387E-03 -.847247E-03 F -.491140E-05 0.440586E-05 G 0.223016E-06 -.669595E-06

And the lenses of the second lens 120, the fourth lens to the sixth lens 140 to 160 are formed aspheric surfaces. If both surfaces of the lenses of the second lens 120 and the fourth lens to the sixth lens 140 to 160 are formed as aspherical surfaces, it is possible to improve various aberrations such as spherical aberration, coma aberration and distortion aberration .

6 is a graph showing aberration diagrams of an imaging lens according to a third embodiment, and is a graph showing longitudinal spherical aberration, astigmatic field curves, and distortion in order from the left.

6, the Y axis means the size of the image, the X axis means the focal length (in mm) and the distortion degree (in%), and the closer the curves are to the Y axis, the better the aberration correction function can be. 6 is a graph showing the relationship between the wavelengths of 435.80 nm, 486.13 nm, 546.07 nm, 587.56 nm and 656.28 nm, and the graph relating to the astigmatism shows a spectrum of light having a wavelength of 587.56 nm (S: Sagittal surface) and a meridional surface (T: tangential surface). Also, the graph relating to the distortion aberration shows a distortion with respect to light having a wavelength of 587.56 nm.

7, the imaging lens according to the fourth exemplary embodiment includes a plurality of lenses 100 to 160 sequentially disposed in a lens barrel 300, And spacing members 210-240 disposed between the plurality of lenses 100-160.

The plurality of lenses may be disposed sequentially from the object side in the image forming side direction, and may include a first lens to an n-th lens, wherein n may be an integer of 2 or more.

The object surface of the first lens 110 may be convex toward the object side and may be disposed to be exposed to the external environment. However, scratches or the like may be generated on the surface of the object surface of the first lens 110 due to external impact The first lens 110 may be a glass lens.

The second lens 120 may be disposed such that the image plane of the first lens 110 and the object plane of the second lens 120 face each other. The plurality of lenses may include first to sixth lenses 110 to 160. The plurality of lenses may be stacked in the vertical direction so that the object surfaces of the plurality of lenses face the image forming surface of the adjacent lens, As shown in FIG.

A gap holding member may be disposed between neighboring lenses, and the gap holding member may include a first gap holding member 210 for maintaining a gap between the first lens 110 and the second lens 120, A second gap holding member 220 disposed between the lens 130 and the fourth lens 140, a third gap holding member 230 disposed between the fourth lens 140 and the fifth lens 150, And a fourth spacing member 240 disposed between the fifth lens 150 and the sixth lens 160. [ The first gap holding member 210 may be disposed such that the image plane of the first lens 110 and the object plane of the second lens 120 are in contact with each other. The first gap holding member 210 may be disposed along the upper surface of the lens barrel 300 so as to support the edge of the image forming surface 111 of the first lens 110 at the outer side of the lens 120 The groove 310 may be formed.

In an embodiment, the first gap retaining member 210 is provided as an O-ring, and may have a waterproof effect when the imaging lens is exposed to the external environment.

The inner diameter size A of the image forming surface of the first lens 110 is equal to the outer diameter size B of the second lens 120 or larger than the outer diameter size B of the second lens 120 .

In this structure, light transmitted through the first lens 110 is incident on the object surface of the second lens 120, and light transmitted through the second lens 120 is incident on the third lens 130, As shown in FIG.

In addition, the extension of the second lens 120 can be disposed at an extended thickness C so as to be in contact with the inner circumferential surface of the lens barrel 300.

The second gap holding member 220 may have an outer circumferential surface 221 contacting the inner circumferential surface 310 of the lens barrel 300 and may maintain a gap between the third lens 130 and the fourth lens 140. The second gap holding member 220 includes a first engaging portion 222 contacting the imaging surface of the third lens 130 and a second engaging portion 223 contacting the object surface of the fourth lens 140 can do.

The first coupling portion 231 and the second coupling portion 232 are coupled to the third lens 130 and the fourth lens 140 and are coupled to the third lens 130 and the fourth lens 140, The gap can be maintained.

The through hole 224 may be formed in the central portion of the gap holding member 220 to form an optical path such that the light transmitted through the third lens 130 can be incident on the fourth lens 140. have.

The second coupling portion 223 may be provided as a coupling surface 223 so as to make surface contact with the object surface of the fourth lens 140. The coupling surface 223 may be provided with a stepped portion (225) may be formed. The lower end of the through hole 224 may be a diaphragm that can transmit the third lens 130 and adjust the amount of light incident on the fourth lens 140.

The height D2 of the step 225 may be smaller than the height D1 of the through hole 224 so that the distance from the object surface of the fourth lens 140 to the diaphragm is smaller than the height D1 of the through- The diaphragm may be disposed between the third lens 130 and the fourth lens 140 so that the diaphragm is closer to the diaphragm than to the diaphragm.

The stepped portion 225 formed on the second gap holding member 220 has a constant height from the image forming surface of the fourth lens 140 and can secure a space in which the central portion of the fourth lens 140 is arranged .

The third gap maintaining member 230 is disposed between the image plane of the fourth lens 140 and the object plane of the fifth lens 150 to maintain a gap between the fourth lens 140 and the fifth lens 150 You can give.

The gap holding member 230 may include a first engaging portion 231 contacting the image forming surface of the fourth lens 140 and a second engaging portion 232 contacting the object surface of the fifth lens 150 have. The first lens 141 of the fourth lens 140 which is in contact with the first coupling portion 231 is coupled to the first coupling portion 231 and the fifth lens 150 May be coupled to the second contact surface 151 and the second engagement portion 232. Here, the first coupling portion 231 and the second coupling portion 232 may be in surface contact with the image plane of the fourth lens 140 and the object plane of the fifth lens 150, respectively.

 The fourth gap maintaining member 240 may include a first coupling portion 241 contacting the imaging surface of the fifth lens 150 and a second coupling portion 242 contacting the object surface of the sixth lens 160. [ have. The first lens 151 and the second lens 160 which are in contact with the first coupling portion 241 and the second coupling portion 242 are coupled to the first contact surface 151 and the first coupling portion 241 of the fifth lens 150, The second contact surface 161 and the second engagement portion 242 may be coupled to each other. Here, the first coupling portion 241 and the second coupling portion 242 may be in surface contact with the image plane of the fifth lens 150 and the object plane of the sixth lens 160, respectively.

The third and fourth spacing members 230 and 240 are arranged in the form of a flat ring on the upper and lower surfaces to form an image forming surface of the fourth lens 140 in contact with the third spacing member 230, The image plane of the fifth lens 150 and the object plane of the sixth lens 160 which are in contact with the fourth gap holding member 240 can be arranged parallel to each other.

According to the above-described embodiment, it is possible to reduce the overall length of the imaging lens while having a wide angle of view with six lenses, and to realize a low distortion image.

The imaging lens described above can be applied to a camera module including a filter that selectively transmits light passing through an imaging lens according to a wavelength and a light receiving element that receives light transmitted through the filter.

The camera module including the imaging lens described above may be embedded in various digital devices such as a digital camera, a smart phone, a notebook, and a tablet PC. In particular, it is embedded in a digital device capable of capturing an image by implementing a wide angle, thereby minimizing the distortion of the photographed image.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood that various modifications and applications are possible. For example, each component specifically shown in the embodiments can be modified and implemented. It is to be understood that all changes and modifications that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

110: first lens 120: second lens
130: third lens 140: fourth lens
150: fifth lens 160: sixth lens
170: Filter 180: Light receiving element
210, 220, 230, 240: spacing member 300: lens barrel
AS: Aperture

Claims (10)

A first lens group including a first lens to a third lens which are arranged sequentially from the object side in the image forming side direction and a second lens group including a fourth lens to a sixth lens,
Wherein the first lens and the second lens have a negative refracting power, the third lens has a positive refracting power, the fourth lens has a positive refracting power and the fifth lens has a negative refracting power, The lens has a positive refractive power,
And the radius of curvature of the object surface of the third lens is larger than 3.1 and smaller than 4.4. The method according to claim 1,
Wherein the first lens and the second lens have a shape of meniscus convex to the object side. The method according to claim 1,
Wherein a radius of curvature of an image-forming surface of the third lens is larger than -8.0 and smaller than -4.0. The method according to claim 1,
And a diaphragm disposed between the third lens and the fourth lens. The method according to claim 1,
And the diaphragm and the fourth lens are disposed at a distance of 25 mu m to 70 mu m. The method according to claim 1,
Wherein at least one of the first lens and the sixth lens is made of glass. The method according to claim 1,
And the shape of the object surface of the fifth lens is formed corresponding to the shape of the imaging surface of the fourth lens. The method according to claim 1,
And the shape of the object surface of the sixth lens is formed corresponding to the shape of the imaging surface of the fifth lens. An imaging lens according to any one of claims 1 to 8;
A filter that selectively transmits light passing through the imaging lens according to a wavelength; And
And a light receiving element for receiving the light transmitted through the filter. A digital device comprising the camera module of claim 9.

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