KR102548990B1 - Optical system - Google Patents

Abstract

An imaging optical system according to an embodiment of the present invention includes, in order from the object side, a first lens having a positive refractive power and having a convex object side surface; a second lens having positive refractive power; a third lens having negative refractive power; a fourth lens having positive refractive power, an object-side surface being concave, and an image-side surface being convex; a fifth lens having negative refractive power; and a sixth lens having negative refractive power, an object-side surface convex and an image-side surface concave, wherein 0.0 < D1/f < 0.1; 0.2 < r1/f < 1.0; and |v2-v3| > 25; can be satisfied. Here, D1 is the air distance between the first lens and the second lens, f is the total focal length of the first to sixth lenses, and r1 is the radius of curvature of the object-side surface of the first lens. , v2 is an Abbe number of the second lens, and v3 is an Abbe number of the third lens.

Description

Imaging optical system {Optical system}

The present invention relates to an imaging optical system.

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

However, since portable terminals tend to become smaller or lighter, there is a limit to implementing high-resolution and high-performance cameras.

In order to solve this problem, recently, a lens of a camera is made of a plastic material that is lighter than glass, and a lens module is composed of 5 or more lenses to realize high resolution.

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

An object according to an embodiment of the present invention is to provide an imaging optical system capable of improving the aberration reduction effect, realizing high resolution, and improving the sensitivity of a lens.

An imaging optical system according to an embodiment of the present invention includes, in order from the object side, a first lens having a positive refractive power and having a convex object side surface; a second lens having positive refractive power; a third lens having negative refractive power; a fourth lens having positive refractive power, an object-side surface being concave, and an image-side surface being convex; a fifth lens having negative refractive power; and a sixth lens having negative refractive power, an object-side surface convex and an image-side surface concave, wherein 0.0 < D1/f < 0.1; 0.2 < r1/f < 1.0; and |v2-v3| > 25; can be satisfied. Here, D1 is the air distance between the first lens and the second lens, f is the total focal length of the first to sixth lenses, and r1 is the radius of curvature of the object-side surface of the first lens. , v2 is an Abbe number of the second lens, and v3 is an Abbe number of the third lens.

According to the imaging optical system according to an embodiment of the present invention, an aberration reduction effect can be improved, high resolution can be implemented, and sensitivity of a lens can be improved.

1 is a configuration diagram of an imaging optical system according to a first embodiment of the present invention;
2 is a configuration diagram of an imaging optical system according to a second embodiment of the present invention;
3 is a configuration diagram of an imaging optical system according to a third embodiment of the present invention;
4 is a configuration diagram of an imaging optical system according to a fourth embodiment of the present invention;
5 is a configuration diagram of an imaging optical system according to a fifth embodiment of the present invention;
6 is a configuration diagram of an imaging optical system according to a sixth embodiment of the present invention;
7 is a configuration diagram of an imaging optical system according to a seventh embodiment of the present invention;
8 is a configuration diagram of an imaging optical system according to an eighth embodiment of the present invention;

Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings. However, the spirit of the present invention is not limited to the presented embodiments, and those skilled in the art who understand the spirit of the present invention may add, change, or delete other components within the scope of the same spirit, through other degenerative inventions or the present invention. Other embodiments included within the scope of the inventive idea can be easily suggested, but it will also be said to be included within the scope of the inventive idea.

In addition, components having the same function within the scope of the same idea appearing in the drawings of each embodiment are described using the same reference numerals.

In the following lens configuration diagram, the thickness, size, and shape of the lens are somewhat exaggerated for description, and in particular, the spherical or aspherical shape presented in the lens configuration diagram is only presented as an example and is not limited thereto.

In addition, the first lens means a lens closest to the object side, and the sixth lens means a lens closest to the image side.

In addition, the front side means a side closer to the object side in the imaging optical system, and the rear side means a side closer to the image sensor or image side in the imaging optical system. Also, in each lens, the first surface means a surface close to the object side (or object side surface), and the second surface means a surface close to the image side (or image side surface). In addition, in this specification, the values for the radius of curvature, thickness, OAL, BFL, and D1 of the lens are all in mm.

An imaging optical system according to an embodiment of the present invention may include 6 lenses.

That is, the imaging optical system according to an embodiment of the present invention includes a first lens 10, a second lens 20, a third lens 30, a fourth lens 40, a fifth lens 50, and a sixth A lens 60 may be included.

However, the imaging optical system according to an embodiment of the present invention is not composed of only 6 lenses and may further include other components as needed. For example, the imaging optical system may include an aperture ST for adjusting the amount of light. In addition, the imaging optical system may further include an infrared cut filter 70 for blocking infrared rays. In addition, the imaging optical system may further include an image sensor 80 for converting an incident image of a subject into an electrical signal. In addition, the imaging optical system may further include a gap maintaining member for adjusting a distance between the lenses.

The first lens 10 to the sixth lens 60 constituting the imaging optical system according to an embodiment of the present invention may be made of a plastic material.

In addition, at least one lens of the first lens 10 to the sixth lens 60 may have an aspheric surface. In addition, the first lens 10 to the sixth lens 60 may have at least one aspherical surface.

That is, at least one of the first and second surfaces of the first lens 10 to the sixth lens 60 may be an aspherical surface.

In addition, the imaging optical system composed of the first lens 10 to the sixth lens 60 sequentially positive/positive/negative/positive/negative/positive or positive/positive/negative/positive/negative/negative from the object side. It may have refractive power.

The imaging optical system configured as described above can improve optical performance through aberration improvement. In addition, the imaging optical system configured as described above can improve the sensitivity of the lens by reducing the refraction angle. Therefore, in the imaging optical system according to an embodiment of the present invention, all six lenses may be made of plastic.

An imaging optical system according to an embodiment of the present invention may satisfy Conditional Expression 1.

[conditional expression 1]

0.6 < f1/f <1.1

In Conditional Expression 1, f is the total focal length [mm] of the imaging optical system, and f1 is the focal length [mm] of the first lens.

An imaging optical system according to an embodiment of the present invention may satisfy Conditional Expression 2.

[conditional expression 2]

|v2-v3| > 25

In Conditional Expression 2, v2 is an Abbe number of the second lens, and v3 is an Abbe number of the third lens.

An imaging optical system according to an embodiment of the present invention may satisfy Conditional Expression 3.

[conditional expression 3]

0.8 < f2/f < 2.0

In Conditional Expression 3, f2 is the focal length [mm] of the second lens, and f is the total focal length [mm] of the imaging optical system.

An imaging optical system according to an embodiment of the present invention may satisfy Conditional Expression 4.

[conditional expression 4]

-1.2 < f3/f < -0.6

In Conditional Expression 4, f3 is the focal length [mm] of the third lens, and f is the total focal length [mm] of the imaging optical system.

An imaging optical system according to an embodiment of the present invention may satisfy Conditional Expression 5.

[conditional expression 5]

1 < f4 / f < 8

In Conditional Expression 5, f4 is the focal length [mm] of the fourth lens, and f is the total focal length [mm] of the imaging optical system.

An imaging optical system according to an embodiment of the present invention may satisfy Conditional Expression 6.

[conditional expression 6]

-12 < f5/f < -1

In Conditional Expression 6, f5 is the focal length [mm] of the fifth lens, and f is the total focal length [mm] of the imaging optical system.

An imaging optical system according to an embodiment of the present invention may satisfy Conditional Expression 7.

[conditional expression 7]

1.0 < OAL/f < 1.8

In Conditional Expression 7, OAL is the distance [mm] from the object side surface of the first lens to the image surface, and f is the total focal length [mm] of the imaging optical system.

An imaging optical system according to an embodiment of the present invention may satisfy Conditional Expression 8.

[conditional expression 8]

0.2 < f1/f2 < 1.5

In Conditional Expression 8, f1 is the focal length [mm] of the first lens, and f2 is the focal length [mm] of the second lens.

An imaging optical system according to an embodiment of the present invention may satisfy Conditional Expression 9.

[conditional expression 9]

-2.0 < f2/f3 < -0.8

In Conditional Expression 9, f2 is the focal length [mm] of the second lens, and f3 is the focal length [mm] of the third lens.

An imaging optical system according to an embodiment of the present invention may satisfy Conditional Expression 10.

[conditional expression 10]

0.1 < BFL/f < 0.6

In Conditional Expression 10, BFL is the distance [mm] from the image side surface of the sixth lens to the image surface, and f is the total focal length [mm] of the imaging optical system.

An imaging optical system according to an embodiment of the present invention may satisfy Conditional Expression 11.

[conditional expression 11]

0.0 < D1/f < 0.1

In Conditional Expression 11, D1 is the air distance [mm] between the first lens and the second lens, and f is the total focal length [mm] of the imaging optical system.

An imaging optical system according to an embodiment of the present invention may satisfy Conditional Expression 12.

[conditional expression 12]

0.2 < r1/f < 1.0

In Conditional Expression 12, r1 is the radius of curvature [mm] of the object-side surface of the first lens, and f is the total focal length [mm] of the imaging optical system.

An imaging optical system according to an embodiment of the present invention may satisfy Conditional Expression 13.

[conditional expression 13]

-0.9 < r4/f < -0.1

In Conditional Expression 13, r4 is the radius of curvature [mm] of the image side surface of the second lens, and f is the total focal length [mm] of the imaging optical system.

Next, the first lens 10 to the sixth lens 60 constituting the imaging optical system according to an embodiment of the present invention will be described.

The first lens 10 may have positive refractive power. In addition, the first lens 10 may have a convex shape on both sides. For example, the first surface (object side surface) of the first lens 10 may be convex toward the object side, and the second surface (upper surface) of the first lens 10 may be convex image side.

At least one of the first surface and the second surface of the first lens 10 may be an aspheric surface. For example, both surfaces of the first lens may be aspheric.

The second lens 20 may have positive refractive power. In addition, the second surface of the second lens 20 may be convex to the image side, and the first surface of the second lens 20 may be concave or convex to the object side.

That is, the first surface of the second lens 20 may not be limited to a specific shape.

At least one surface of the first surface and the second surface of the second lens 20 may be an aspheric surface. For example, both surfaces of the second lens 20 may be aspherical.

The third lens 30 may have negative refractive power. In addition, the first surface of the third lens 30 may have a concave shape. Alternatively, the second surface of the third lens 30 may have a concave or convex shape.

At least one surface of the first surface and the second surface of the third lens 30 may be an aspherical surface. For example, both surfaces of the third lens 30 may be aspherical.

The fourth lens 40 may have positive refractive power. In addition, the fourth lens 40 may have a meniscus shape convex upward. In other words, the first surface of the fourth lens 40 may have a concave shape, and the second surface of the fourth lens 40 may have an upwardly convex shape.

At least one surface of the first surface and the second surface of the fourth lens 40 may be an aspheric surface. For example, both surfaces of the fourth lens 40 may be aspherical.

The fifth lens 50 may have negative refractive power. In addition, the fifth lens 50 may have a first surface convex toward the object and a second surface concave. In addition, an inflection point may be formed on at least one of the first and second surfaces of the fifth lens 50 .

The fifth lens 50 having such a shape may be advantageous in condensing the light refracted from the fourth lens 40 to the sixth lens 60 . At least one surface of the first surface and the second surface of the fifth lens 50 may be an aspheric surface. For example, both surfaces of the fifth lens 50 may be aspherical.

The sixth lens 60 may have positive or negative refractive power. That is, the sixth lens 60 may have positive refractive power or negative refractive power.

Here, the refractive power of the sixth lens 60 may depend on the shapes of the second lens 20 and the third lens 30 . For example, when both the first surface of the second lens 20 and the first surface of the third lens 30 are convex toward the object, the refractive power of the sixth lens 60 may be positive.

However, the refractive power of the sixth lens 60 is not limited to the above conditions. For example, even when both the first surface of the second lens 20 and the first surface of the third lens 30 are convex toward the object, the refractive power of the sixth lens 60 may be negative.

The sixth lens 60 may have a shape in which a first surface is convex and a second surface is concave. In addition, an inflection point may be formed on at least one of the first and second surfaces of the sixth lens 60 .

For example, the second surface of the sixth lens 60 may be concave at the center of the optical axis and convex toward the edge. In addition, at least one surface of the first surface and the second surface of the sixth lens 60 may be an aspheric surface. For example, both surfaces of the sixth lens 60 may be aspheric.

In the imaging optical system configured as described above, since a plurality of lenses perform an aberration correction function, aberration improvement performance can be improved. In addition, the imaging optical system can improve the sensitivity of the lens by reducing the refraction angle of the lens. Accordingly, all lenses of the imaging optical system may be made of a plastic material having lower optical performance than a glass material, and through this, the manufacturing cost of the lens module may be lowered and manufacturing efficiency may be increased.

An imaging optical system according to a first embodiment of the present invention will be described with reference to FIG. 1 .

An imaging optical system according to a first embodiment of the present invention includes a first lens 10, a second lens 20, a third lens 30, a fourth lens 40, a fifth lens 50, and a sixth lens. 60, and may further include an infrared cut filter 70, an image sensor 80, and an aperture ST.

Here, as shown in Table 1, the distance OAL from the first surface of the first lens 10 to the first surface (top surface) of the image sensor 80 is 6.25 mm, and the sixth lens 60 ) is 1.43717 mm from the top side to the top side (BFL). And the focal length of the first lens 10 is 3.89484 mm, the focal length of the second lens 20 is 6.32828 mm, the focal length of the third lens 30 is -4.4675 mm, and the focal length of the fourth lens 40 is The distance is 28.367 mm, the focal length of the fifth lens 50 is -44.005 mm, the focal length of the sixth lens 60 is -35.257 mm, and the focal length of the entire optical system is 4.66679 mm.

Other lens characteristics (radius of curvature, lens thickness or distance between lenses, refractive index, Abbe number) are shown in Table 2.

In the first embodiment of the present invention, the first lens 10 may have a positive refractive power and have a convex shape on both sides. The second lens 20 may have a positive refractive power, and may have a concave first surface and a convex second surface. The third lens 30 may have negative refractive power and may have a concave first surface. The fourth lens 40 may have a positive refractive power and have a meniscus shape convex upward. The fifth lens 50 may have negative refractive power, and may have a convex first surface and a concave second surface. The sixth lens 60 may have negative refractive power, and may have a convex first surface and a concave second surface. In addition, inflection points may be formed on the first and second surfaces of the sixth lens 60 . Also, the diaphragm ST may be disposed in front of the first lens 10 .

Meanwhile, each surface of the first lens 10 to the sixth lens 60 may have an aspherical surface coefficient as shown in Table 3. That is, the second surface of the first lens 10 to the second surface of the sixth lens 60 may all be aspheric surfaces.

Meanwhile, referring to Table 4, it can be seen that the imaging optical system according to the first embodiment of the present invention satisfies Conditional Expressions 1 to 13 described above, and through this, the optical performance of the lens can be improved.

An imaging optical system according to a second embodiment of the present invention will be described with reference to FIG. 2 .

An imaging optical system according to a second embodiment of the present invention includes a first lens 10, a second lens 20, a third lens 30, a fourth lens 40, a fifth lens 50, and a sixth lens. 60, and may further include an infrared cut filter 70, an image sensor 80, and an aperture ST.

Here, as shown in Table 5, the distance OAL from the first surface of the first lens 10 to the first surface (top surface) of the image sensor 80 is 6.24 mm, and the sixth lens 60 ) is 1.42951 mm. And the focal length of the first lens 10 is 3.85605 mm, the focal length of the second lens 20 is 7.33396 mm, the focal length of the third lens 30 is -4.4621 mm, the focal length of the fourth lens 40 The distance is 12.9796 mm, the focal length of the fifth lens 50 is -16.555 mm, the focal length of the sixth lens 60 is -59.668 mm, and the focal length of the entire optical system is 4.66665 mm.

Other lens characteristics (radius of curvature, lens thickness or distance between lenses, refractive index, Abbe number) are shown in Table 6.

In the second embodiment of the present invention, the first lens 10 may have a positive refractive power and have a convex shape on both sides. The second lens 20 may have a positive refractive power, and may have a concave first surface and a convex second surface. The third lens 30 may have negative refractive power and may have a concave first surface. The fourth lens 40 may have a positive refractive power and have a meniscus shape convex upward. The fifth lens 50 may have negative refractive power, and may have a convex first surface and a concave second surface. In addition, inflection points may be formed on the first and second surfaces of the fifth lens 50 . The sixth lens 60 may have negative refractive power, and may have a convex first surface and a concave second surface. In addition, inflection points may be formed on the first and second surfaces of the sixth lens 60 . Also, the diaphragm ST may be disposed in front of the first lens 10 .

Meanwhile, each surface of the first lens 10 to the sixth lens 60 may have an aspherical surface coefficient as shown in Table 7. That is, the second surface of the first lens 10 to the second surface of the sixth lens 60 may all be aspheric surfaces.

Meanwhile, referring to Table 8, it can be seen that the imaging optical system according to the second embodiment of the present invention satisfies Conditional Expressions 1 to 13 described above, and through this, the optical performance of the lens can be improved.

An imaging optical system according to a third embodiment of the present invention will be described with reference to FIG. 3 .

An imaging optical system according to a third embodiment of the present invention includes a first lens 10, a second lens 20, a third lens 30, a fourth lens 40, a fifth lens 50, and a sixth lens. 60, and may further include an infrared cut filter 70, an image sensor 80, and an aperture ST.

Here, as shown in Table 9, the distance OAL from the first surface of the first lens 10 to the first surface (top surface) of the image sensor 80 is 6.20491 mm, and the sixth lens 60 ) from the top side to the top side (BFL) is 1.45177 mm. And the focal length of the first lens 10 is 3.85934 mm, the focal length of the second lens 20 is 7.19075 mm, the focal length of the third lens 30 is -4.4903 mm, and the focal length of the fourth lens 40 is The distance is 13.0692 mm, the focal length of the fifth lens 50 is -16.427 mm, the focal length of the sixth lens 60 is -107.58 mm, and the focal length of the entire optical system is 4.5898 mm.

Other lens characteristics (radius of curvature, lens thickness or distance between lenses, refractive index, Abbe number) are shown in Table 10.

In the third embodiment of the present invention, the first lens 10 may have a positive refractive power and have a convex shape on both sides. The second lens 20 may have a positive refractive power, and may have a concave first surface and a convex second surface. The third lens 30 may have negative refractive power and may have a concave first surface. The fourth lens 40 may have a positive refractive power and have a meniscus shape convex upward. The fifth lens 50 may have negative refractive power, and may have a convex first surface and a concave second surface. In addition, inflection points may be formed on the first and second surfaces of the fifth lens 50 . The sixth lens 60 may have negative refractive power, and may have a convex first surface and a concave second surface. In addition, inflection points may be formed on the first and second surfaces of the sixth lens 60 . Also, the diaphragm ST may be disposed in front of the first lens 10 .

Meanwhile, each surface of the first lens 10 to the sixth lens 60 may have an aspherical surface coefficient as shown in Table 11. That is, the second surface of the first lens 10 to the second surface of the sixth lens 60 may all be aspheric surfaces.

Meanwhile, referring to Table 12, it can be seen that the imaging optical system according to the third embodiment of the present invention satisfies Conditional Expressions 1 to 13 described above, and through this, the optical performance of the lens can be improved.

An imaging optical system according to a fourth embodiment of the present invention will be described with reference to FIG. 4 .

An imaging optical system according to a fourth embodiment of the present invention includes a first lens 10, a second lens 20, a third lens 30, a fourth lens 40, a fifth lens 50, and a sixth lens. 60, and may further include an infrared cut filter 70, an image sensor 80, and an aperture ST.

Here, as shown in Table 13, the distance OAL from the first surface of the first lens 10 to the first surface (top surface) of the image sensor 80 is 5.97 mm, and the sixth lens 60 ) is 1.45268 mm from the top side to the top side (BFL). And the focal length of the first lens 10 is 3.8346 mm, the focal length of the second lens 20 is 7.18763 mm, the focal length of the third lens 30 is -4.6043 mm, the focal length of the fourth lens 40 The distance is 14.4975 mm, the focal length of the fifth lens 50 is -33.339 mm, the focal length of the sixth lens 60 is -27.872 mm, and the focal length of the entire optical system is 4.45053 mm.

Other lens characteristics (radius of curvature, lens thickness or distance between lenses, refractive index, Abbe number) are shown in Table 14.

In the fourth embodiment of the present invention, the first lens 10 may have a positive refractive power and have a convex shape on both sides. The second lens 20 may have a positive refractive power, and may have a concave first surface and a convex second surface. The third lens 30 may have negative refractive power and may have a concave first surface. The fourth lens 40 may have a positive refractive power and have a meniscus shape convex upward. The fifth lens 50 may have negative refractive power, and may have a convex first surface and a concave second surface. In addition, inflection points may be formed on the first and second surfaces of the fifth lens 50 . The sixth lens 60 may have negative refractive power, and may have a convex first surface and a concave second surface. In addition, inflection points may be formed on the first and second surfaces of the sixth lens 60 . Also, the diaphragm ST may be disposed in front of the first lens 10 .

Meanwhile, each surface of the first lens 10 to the sixth lens 60 may have an aspherical surface coefficient as shown in Table 15. That is, the second surface of the first lens 10 to the second surface of the sixth lens 60 may all be aspheric surfaces.

Meanwhile, referring to Table 16, it can be seen that the imaging optical system according to the fourth embodiment of the present invention satisfies Conditional Expressions 1 to 13 described above, and through this, the optical performance of the lens can be improved.

An imaging optical system according to a fifth embodiment of the present invention will be described with reference to FIG. 5 .

An imaging optical system according to a fifth embodiment of the present invention includes a first lens 10, a second lens 20, a third lens 30, a fourth lens 40, a fifth lens 50, and a sixth lens. 60, and may further include an infrared cut filter 70, an image sensor 80, and an aperture ST.

Here, as shown in Table 17, the distance OAL from the first surface of the first lens 10 to the first surface (top surface) of the image sensor 80 is 6.10362 mm, and the sixth lens 60 ) is 1.45486 mm from the top side to the top side (BFL). And the focal length of the first lens 10 is 3.87953 mm, the focal length of the second lens 20 is 6.91968 mm, the focal length of the third lens 30 is -4.4607 mm, and the focal length of the fourth lens 40 is The distance is 13.2566 mm, the focal length of the fifth lens 50 is -17.591 mm, the focal length of the sixth lens 60 is -4547.3 mm, and the focal length of the entire optical system is 4.43963 mm.

Other lens characteristics (radius of curvature, lens thickness or distance between lenses, refractive index, Abbe number) are shown in Table 18.

In the fifth embodiment of the present invention, the first lens 10 may have positive refractive power and may have a convex shape on both sides. The second lens 20 may have a positive refractive power, and may have a concave first surface and a convex second surface. The third lens 30 may have negative refractive power and may have a concave first surface. The fourth lens 40 may have a positive refractive power and have a meniscus shape convex upward. The fifth lens 50 may have negative refractive power, and may have a convex first surface and a concave second surface. In addition, inflection points may be formed on the first and second surfaces of the fifth lens 50 . The sixth lens 60 may have negative refractive power, and may have a convex first surface and a concave second surface. In addition, inflection points may be formed on the first and second surfaces of the sixth lens 60 . Also, the diaphragm ST may be disposed in front of the first lens 10 .

Meanwhile, each surface of the first lens 10 to the sixth lens 60 may have an aspherical surface coefficient as shown in Table 19. That is, the second surface of the first lens 10 to the second surface of the sixth lens 60 may all be aspheric surfaces.

Meanwhile, referring to Table 20, it can be seen that the imaging optical system according to the fifth embodiment of the present invention satisfies Conditional Expressions 1 to 13 described above, and through this, the optical performance of the lens can be improved.

An imaging optical system according to a sixth embodiment of the present invention will be described with reference to FIG. 6 .

An imaging optical system according to a sixth embodiment of the present invention includes a first lens 10, a second lens 20, a third lens 30, a fourth lens 40, a fifth lens 50, and a sixth lens. 60, and may further include an infrared cut filter 70, an image sensor 80, and an aperture ST.

Here, as shown in Table 21, the distance OAL from the first surface of the first lens 10 to the first surface (top surface) of the image sensor 80 is 6.1024 mm, and the sixth lens 60 ) from the top side to the top side (BFL) is 1.45488 mm. And the focal length of the first lens 10 is 3.88096 mm, the focal length of the second lens 20 is 6.91542 mm, the focal length of the third lens 30 is -4.4639 mm, and the focal length of the fourth lens 40 is The distance is 13.2749 mm, the focal length of the fifth lens 50 is -17.515 mm, the focal length of the sixth lens 60 is 6182.52 mm, and the focal length of the entire optical system is 4.43837 mm.

Other lens characteristics (radius of curvature, lens thickness or distance between lenses, refractive index, Abbe number) are shown in Table 22.

In the sixth embodiment of the present invention, the first lens 10 may have positive refractive power and may have a convex shape on both sides. The second lens 20 may have a positive refractive power, and may have a concave first surface and a convex second surface. The third lens 30 may have negative refractive power and may have a concave first surface. The fourth lens 40 may have a positive refractive power and have a meniscus shape convex upward. The fifth lens 50 may have negative refractive power, and may have a convex first surface and a concave second surface. In addition, inflection points may be formed on the first and second surfaces of the fifth lens 50 . The sixth lens 60 may have positive refractive power, and may have a convex first surface and a concave second surface. In addition, inflection points may be formed on the first and second surfaces of the sixth lens 60 . Also, the diaphragm ST may be disposed in front of the first lens 10 .

Meanwhile, each surface of the first lens 10 to the sixth lens 60 may have an aspherical surface coefficient as shown in Table 23. That is, the second surface of the first lens 10 to the second surface of the sixth lens 60 may all be aspheric surfaces.

Meanwhile, referring to Table 24, it can be seen that the imaging optical system according to the sixth embodiment of the present invention satisfies Conditional Expressions 1 to 13 described above, and through this, the optical performance of the lens can be improved.

An imaging optical system according to a seventh embodiment of the present invention will be described with reference to FIG. 7 .

An imaging optical system according to a seventh embodiment of the present invention includes a first lens 10, a second lens 20, a third lens 30, a fourth lens 40, a fifth lens 50, and a sixth lens. 60, and may further include an infrared cut filter 70, an image sensor 80, and an aperture ST.

Here, as shown in Table 25, the distance OAL from the first surface of the first lens 10 to the first surface (top surface) of the image sensor 80 is 6.47 mm, and the sixth lens 60 ) is 1.44185 mm from the upper surface to the upper surface (BFL). And the focal length of the first lens 10 is 4.56249 mm, the focal length of the second lens 20 is 5.34804 mm, the focal length of the third lens 30 is -4.4736 mm, and the focal length of the fourth lens 40 is The distance is 13.6989 mm, the focal length of the fifth lens 50 is -45.613 mm, the focal length of the sixth lens 60 is -12.266 mm, and the focal length of the entire optical system is 5.03037 mm.

Other lens characteristics (radius of curvature, lens thickness or distance between lenses, refractive index, Abbe number) are shown in Table 26.

In the seventh embodiment of the present invention, the first lens 10 may have a positive refractive power and have a convex shape on both sides. The second lens 20 may have positive refractive power and may have a convex second surface. The third lens 30 may have negative refractive power and may have a concave first surface. The fourth lens 40 may have a positive refractive power and have a meniscus shape convex upward. The fifth lens 50 may have negative refractive power, and may have a concave first surface and a convex second surface. The sixth lens 60 may have negative refractive power, and may have a convex first surface and a concave second surface. In addition, inflection points may be formed on the first and second surfaces of the sixth lens 60 . Also, the diaphragm ST may be disposed in front of the first lens 10 .

Meanwhile, each surface of the first lens 10 to the sixth lens 60 may have an aspherical surface coefficient as shown in Table 27. That is, the second surface of the first lens 10 to the second surface of the sixth lens 60 may all be aspheric surfaces.

Meanwhile, referring to Table 28, it can be seen that the imaging optical system according to the seventh embodiment of the present invention satisfies Conditional Expressions 1 to 13 described above, and through this, the optical performance of the lens can be improved.

An imaging optical system according to an eighth embodiment of the present invention will be described with reference to FIG. 8 .

An imaging optical system according to an eighth embodiment of the present invention includes a first lens 10, a second lens 20, a third lens 30, a fourth lens 40, a fifth lens 50, and a sixth lens. 60, and may further include an infrared cut filter 70, an image sensor 80, and an aperture ST.

Here, as shown in Table 29, the distance OAL from the first surface of the first lens 10 to the first surface (top surface) of the image sensor 80 is 6.58701 mm, and the sixth lens 60 ) from the top side to the top side (BFL) is 1.40308 mm. And the focal length of the first lens 10 is 5.01632 mm, the focal length of the second lens 20 is 4.97111 mm, the focal length of the third lens 30 is -4.311 mm, and the focal length of the fourth lens 40 is The distance is 8.74698 mm, the focal length of the fifth lens 50 is -14.576 mm, the focal length of the sixth lens 60 is -15.839 mm, and the focal length of the entire optical system is 5.18292 mm.

Other lens characteristics (radius of curvature, lens thickness or distance between lenses, refractive index, Abbe number) are shown in Table 30.

In the eighth embodiment of the present invention, the first lens 10 may have a positive refractive power and have a convex shape on both sides. The second lens 20 may have positive refractive power and may have a convex second surface. The third lens 30 may have negative refractive power and may have a concave first surface. The fourth lens 40 may have a positive refractive power and have a meniscus shape convex upward. The fifth lens 50 may have negative refractive power, and may have a concave first surface and a convex second surface. The sixth lens 60 may have negative refractive power, and may have a convex first surface and a concave second surface. In addition, inflection points may be formed on the first and second surfaces of the sixth lens 60 . Also, the diaphragm ST may be disposed in front of the first lens 10 .

Meanwhile, each surface of the first lens 10 to the sixth lens 60 may have an aspherical surface coefficient as shown in Table 31. That is, the second surface of the first lens 10 to the second surface of the sixth lens 60 may all be aspheric surfaces.

Meanwhile, referring to Table 32, it can be seen that the imaging optical system according to the eighth embodiment of the present invention satisfies Conditional Expressions 1 to 13 described above, and through this, the optical performance of the lens can be improved.

In the above, the configuration and characteristics of the present invention have been described based on the embodiments according to the present invention, but the present invention is not limited thereto, and various changes or modifications can be made within the spirit and scope of the present invention. It is apparent to those skilled in the art, and therefore such changes or modifications are intended to fall within the scope of the appended claims.

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

Claims (15)

In order from the object side,
a first lens having positive refractive power and having a convex object-side surface;
a second lens having positive refractive power;
a third lens having negative refractive power;
a fourth lens having positive refractive power, an object-side surface being concave, and an image-side surface being convex;
a fifth lens having negative refractive power; and
A sixth lens having negative refractive power, an object-side surface being convex and an image-side surface being concave;
0.0 < D1/f <0.1;
0.2 < r1/f <1.0; and
|v2-v3| >25; D1 is the air distance between the first lens and the second lens, f is the total focal length of the first lens to the sixth lens, and r1 is the object of the first lens A radius of curvature of a side surface, v2 is an Abbe number of the second lens, and v3 is an Abbe number of the third lens.
According to claim 1,
-12 < f5/f < -1, where f5 is the focal length of the fifth lens.
According to claim 1,
1.0 < OAL/f < 1.8, where OAL is the distance from the object-side surface of the first lens to the image surface.
According to claim 1,
0.1 < BFL/f < 0.6, wherein BFL is a distance from the image-side surface of the sixth lens to the image surface.
According to claim 1,
The second lens is an imaging optical system having a convex object-side surface.
According to claim 5,
The third lens has a concave image-side surface.
According to claim 6,
The fifth lens is an imaging optical system having a concave object-side surface and a convex image-side surface.
According to claim 1,
0.6 < f1/f <1.1, where f1 is the focal length of the first lens.
According to claim 1,
0.8 < f2/f < 2.0, where f2 is the focal length of the second lens.
According to claim 1,
-1.2 < f3/f < -0.6, where f3 is the focal length of the third lens.
According to claim 1,
1 < f4/f < 8, where f4 is the focal length of the fourth lens.
According to claim 1,
0.2 < f1/f2 < 1.5, f1 is the focal length of the first lens, and f2 is the focal length of the second lens.
According to claim 1,
-2.0 < f2/f3 < -0.8, f2 is the focal length of the second lens, and f3 is the focal length of the third lens.
According to claim 1,
-0.9 < r4/f < -0.1, and r4 is the radius of curvature of the image-side surface of the second lens.
According to claim 1,
The first lens to the sixth lens are provided with a plastic material, and object-side surfaces and image-side surfaces of the first lens to the sixth lens are aspheric surfaces.

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