KR102535696B1 - Imaging Lens System - Google Patents

Abstract

An imaging optical system according to the present invention includes a first lens having a concave image side, sequentially disposed from the object side; a second lens having refractive power; a third lens having a concave image side; a fourth lens in which an object side or an image side is convex; a fifth lens having refractive power; a sixth lens having a concave image side; and a seventh lens having negative refractive power.

Description

Imaging optical system {Imaging Lens System}

The present invention relates to an imaging optical system including 7 lenses.

A miniature camera is mounted on the wireless terminal. For example, a small camera is mounted on the front and back of the wireless terminal, respectively. Since these small cameras are used for various purposes such as outdoor landscape photography and indoor portrait photography, performance comparable to that of general cameras is required. However, it is difficult to implement high performance in a small camera because the mounting space is limited by the size of the wireless terminal. Accordingly, there is a need to develop an imaging optical system capable of improving the performance of a small camera without increasing the size of the small camera.

For reference, there are Patent Documents 1 and 2 as prior art related to the present invention.

US 2014-0160580 A US 2016-0033742 A

The present invention is to solve the above problems, and an object of the present invention is to provide an imaging optical system capable of improving the performance of a compact camera.

An imaging optical system according to an embodiment of the present invention for achieving the above object includes a first lens having a concave image side, sequentially disposed from the object side; a second lens having refractive power; a third lens having a concave image side; a fourth lens in which an object side or an image side is convex; a fifth lens having refractive power; a sixth lens having a concave image side; and a seventh lens having negative refractive power.

The present invention can improve the performance of compact cameras.

1 is a configuration diagram of an imaging optical system according to a first embodiment of the present invention;
2 and 3 are aberration curves of the imaging optical system shown in FIG. 1
4 is a configuration diagram of an imaging optical system according to a second embodiment of the present invention;
5 and 6 are configuration diagrams of the imaging optical system shown in FIG. 4;
7 is a configuration diagram of an imaging optical system according to a third embodiment of the present invention;
8 and 9 are configuration diagrams of the imaging optical system shown in FIG. 7;
10 is a configuration diagram of an imaging optical system according to a fourth embodiment of the present invention;
11 and 12 are configuration diagrams of the imaging optical system shown in FIG. 10
13 is a configuration diagram of an imaging optical system according to a fifth embodiment of the present invention;
14 and 15 are configuration diagrams of the imaging optical system shown in FIG. 13

Hereinafter, preferred embodiments of the present invention will be described in detail based on the accompanying drawings.

In describing the present invention below, terms referring to the components of the present invention are named in consideration of the functions of each component, so they should not be understood as limiting the technical components of the present invention.

In addition, throughout the specification, that a component is 'connected' to another component includes not only the case where these components are 'directly connected', but also the case where they are 'indirectly connected' through other components. means that In addition, 'including' a certain component means that other components may be further included, rather than excluding other components unless otherwise stated.

In this specification, the first lens refers to a lens closest to the object (or subject), and the seventh lens refers to a lens closest to the image surface (or image sensor). In this specification, the units of the radius of curvature of the lens, thickness, TL (distance from the object side of the first lens to the image surface), ImgH (half of the diagonal length of the image surface), and focal length are mm.

The thickness of the lens, the distance between the lenses, TL is the distance from the optical axis of the lens. In addition, in the description of the shape of the lens, a convex shape on one surface means that a paraxial region of the corresponding surface is convex, and a concave shape means that the paraxial region of the corresponding 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 surface of the lens is described as having a concave shape, the edge portion of the lens may be convex.

The imaging optical system includes 7 lenses. For example, the imaging optical system may include a first lens, a second lens, a third lens, a fourth lens, a fifth lens, a sixth lens, and a seventh lens sequentially disposed from the object side.

The first lens has refractive power. For example, the first lens has positive refractive power. The first lens has a shape in which one surface is convex. For example, the first lens has a shape in which an object side surface is convex.

The first lens includes an aspheric surface. For example, both surfaces of the first lens may be aspherical. The first lens may be made of a material having high light transmittance and excellent workability. For example, the first lens may be made of a plastic material. The first lens has a low refractive index. For example, the refractive index of the first lens may be less than 1.6.

The second lens has refractive power. For example, the second lens has negative refractive power. The second lens has a convex shape on one surface. For example, the second lens may have a shape in which the side of the object is convex.

The second lens includes an aspheric surface. For example, the object side of the second lens may have an aspheric surface. The second lens may be made of a material having high light transmittance and excellent workability. For example, the second lens may be made of a plastic material. The second lens has a higher refractive index than the first lens. For example, the refractive index of the second lens may be 1.65 or more.

The third lens has refractive power. For example, the third lens may have positive refractive power. The third lens has a shape in which one surface is convex. For example, the third lens may have a shape in which an object side surface is convex.

The third lens includes an aspheric surface. For example, an image side surface of the third lens may be an aspherical surface. The third lens may be made of a material having high light transmittance and excellent workability. For example, the third lens may be made of a plastic material. The third lens has a refractive index substantially similar to that of the first lens. For example, the refractive index of the third lens may be less than 1.6.

The fourth lens has refractive power. For example, the fourth lens has positive or negative refractive power. The fourth lens has a shape in which one surface is concave and the other surface is convex. For example, the fourth lens may have a shape in which the object side surface is concave and the image side surface is convex, or the object side surface is convex and the image side surface is concave.

The fourth lens includes an aspheric surface. For example, both surfaces of the fourth lens may be aspherical. The fourth lens may be made of a material having high light transmittance and excellent workability. For example, the fourth lens may be made of a plastic material. The fourth lens has substantially the same refractive index as the first lens. For example, the refractive index of the fourth lens may be less than 1.6.

The fifth lens has refractive power. For example, the fifth lens may have positive or negative refractive power.

The fifth lens includes an aspheric surface. For example, both surfaces of the fifth lens may be aspherical. The fifth lens may be made of a material having high light transmittance and excellent workability. For example, the fifth lens may be made of a plastic material. The fifth lens has a higher refractive index than the fourth lens. For example, the refractive index of the fifth lens may be 1.6 or more.

The sixth lens has refractive power. For example, the sixth lens has positive or negative refractive power. The sixth lens has a concave shape on one surface. For example, the sixth lens may have a concave image side surface. The sixth lens may have a shape having an inflection point. For example, one or more inflection points may be formed on both sides of the sixth lens.

The sixth lens includes an aspheric surface. For example, both surfaces of the sixth lens may be aspherical. The sixth lens may be made of a material having high light transmittance and excellent workability. For example, the sixth lens may be made of a plastic material. The sixth lens has a refractive index substantially similar to that of the fifth lens. For example, the refractive index of the sixth lens may be 1.6 or more.

The seventh lens has refractive power. For example, the seventh lens has negative refractive power. The seventh lens may have a shape in which one surface is convex. For example, the seventh lens may have a shape in which an object side surface is convex. The seventh lens may have a shape having an inflection point. For example, one or more inflection points may be formed on both sides of the seventh lens.

The seventh lens includes an aspheric surface. For example, both surfaces of the seventh lens may be aspheric. The seventh lens may be made of a material having high light transmittance and excellent workability. For example, the seventh lens may be made of a plastic material. The seventh lens has a lower refractive index than the sixth lens. For example, the refractive index of the seventh lens may be less than 1.6.

Aspheric surfaces of the first to seventh lenses may be expressed by Equation 1.

In Equation 1, c is the reciprocal of the radius of curvature of the corresponding lens, k is the conic constant, r is the distance from an arbitrary point on the aspherical surface to the optical axis, A to J are aspheric constants, and Z (or SAG) is the aspheric surface It is the height in the optical axis direction from an arbitrary point on the image to the apex of the aspherical surface.

In the imaging optical system, a lens group including first to third lenses may have positive refractive power. For example, the combined focal length of the first to third lenses may be a positive number. In the imaging optical system, the lens group including the fourth to sixth lenses may have negative refractive power. For example, the combined focal length of the fourth to sixth lenses may be a negative number.

The imaging optical system further includes a filter, an image sensor, and a diaphragm.

A filter is disposed between the seventh lens and the image sensor. The filter may block some wavelengths of light so that clear images can be realized. For example, a filter may block infrared wavelengths of light.

An image sensor forms an upper surface. For example, the surface of the image sensor may form a top surface.

The diaphragm is arranged to adjust the amount of light incident on the lens. For example, the diaphragm may be disposed between the second and third lenses or between the third and fourth lenses.

The imaging optical system may satisfy the following Conditional Expressions.

[Conditional Expression 1] 0.8 < TL/f < 1.4

[Conditional Expression 2] 1.2 < TL/ImgH < 2.0

[Conditional Expression 3] 0.8 < Td/f < 1.2

[Conditional Expression 4] 0.65 < f1/f < 1.5

[Conditional Expression 5] 1.2 < f3/f < 8.0

[Conditional Expression 6] 0.75 < f123/f <1.3

[Conditional Expression 7] -8.0 < f4567/f < -1.5

[Conditional Expression 8] -0.75 < f1/f2 < -0.3

[Conditional Expression 9] 0.35 < r4/f < 0.95

[Conditional Expression 10] 0.6 < r12/f < 1.7

[Conditional Expression 11] 0.15 < (r3-r4)/(r3+r4) < 0.5

[Conditional Expression 12] 1.1 < |f/f1|+|f/f2| < 2.1

[Conditional Expression 13] ∑cti < 3.8 (i=1, 2, 3 ....7)

[Conditional Expression 14] 0.65 < ImgH / f

[Conditional Expression 15] 2.8 < ct1/ct2

[Conditional Expression 16] 28 < v1 - v2 < 42

[Conditional Expression 17] 1.6 < Nmax

[Conditional Expression 18] ctmin < 0.3

[Conditional Expression 19] 1.62 < (N2+N5+N6)/3

In the above conditional expression, TL is the distance from the object side of the first lens to the image plane, f is the total focal length, ImgH is 1/2 of the diagonal length of the image plane, Td is the sum of the thicknesses of the first to seventh lenses , f1 is the focal length of the first lens, f2 is the focal length of the second lens, f123 is the combined focal length of the first to third lenses, f4567 is the combined focal length of the fourth to seventh lenses, r3 is the radius of curvature of the object side of the second lens, r4 is the radius of curvature of the image side of the second lens, r12 is the radius of curvature of the image side of the sixth lens, and ct1 is the thickness at the optical axis portion of the first lens , ct2 is the thickness of the optical axis of the second lens, ct3 is the thickness of the optical axis of the third lens, ct4 is the thickness of the optical axis of the fourth lens, and ct5 is the optical axis of the fifth lens. , ct6 is the thickness of the optical axis of the sixth lens, ct7 is the thickness of the optical axis of the seventh lens, v1 is the Abbe number of the first lens, v2 is the Abbe number of the second lens, Nmax is the refractive index value of the lens having the largest refractive index among the first to seventh lenses, ctmin is the thickness value of the lens having the smallest optical axis thickness among the first to seventh lenses, and N2 is the refractive index of the second lens , N5 is the refractive index of the fifth lens, and N6 is the refractive index of the sixth lens.

Next, an imaging optical system according to various embodiments will be described.

First, an imaging optical system according to the first embodiment will be described with reference to FIG. 1 .

The imaging optical system 100 includes a first lens 110, a second lens 120, a third lens 130, a fourth lens 140, a fifth lens 150, a sixth lens 160, and a seventh lens. A lens 170 is included.

The first lens 110 has a positive refractive power, and has a convex object side surface and a concave image side surface. The second lens 120 has negative refractive power and has a convex object side surface and a concave image side surface. The third lens 130 has a positive refractive power and has a convex object side surface and a concave image side surface. The fourth lens 140 has a positive refractive power and has a concave object side surface and a convex image side surface. The fifth lens 150 has negative refractive power and has a concave object side surface and a concave image side surface. The sixth lens 160 has a positive refractive power and has a convex object side surface and a concave image side surface. In addition, the sixth lens 160 has a shape in which an inflection point is formed on at least one of the object side and the image side. The seventh lens 170 has negative refractive power and has a convex object side surface and a concave image side surface. In addition, the seventh lens 170 has a shape in which an inflection point is formed on at least one of the object side and the image side.

The imaging optical system 100 further includes a filter 180, an image sensor 190, and an aperture ST. The filter 180 is disposed between the seventh lens 170 and the image sensor 190, and the diaphragm ST is disposed between the second lens 120 and the third lens 130.

The imaging optical system 100 includes a plurality of lenses having high refractive indices. For example, the second lens 120, the fifth lens 150, and the sixth lens 160 may have a refractive index of 1.6 or more. In other words, the refractive indices of the second lens 120, the fifth lens 150, and the sixth lens 160 may be greater than 1.65 and less than 2.0.

The imaging optical system 100 is configured to implement a bright optical system. For example, the F No. of the imaging optical system 100. It is 1.581. The imaging optical system 100 has a wide angle of view. For example, the total angle of view of the imaging optical system 100 is 78.43 degrees.

In the imaging optical system according to this embodiment, the combined focal length f123 of the first to third lenses is 4.469 mm, and the combined focal length f4567 of the fourth to sixth lenses is -12.1516 mm.

The imaging optical system configured as above exhibits aberration characteristics as shown in FIGS. 2 and 3 . Table 1 shows lens characteristics of the imaging optical system according to the present embodiment, and Table 2 shows aspheric surface values of the imaging optical system according to the present embodiment.

An imaging optical system according to a second embodiment will be described with reference to FIG. 4 .

The imaging optical system 200 includes a first lens 210, a second lens 220, a third lens 230, a fourth lens 240, a fifth lens 250, a sixth lens 260, and a seventh lens. A lens 270 is included.

The first lens 210 has a positive refractive power and has a convex object side surface and a concave image side surface. The second lens 220 has negative refractive power and has a convex object side surface and a concave image side surface. The third lens 230 has a positive refractive power and has a convex object side surface and a concave image side surface. The fourth lens 240 has negative refractive power and has a convex object side surface and a concave image side surface. The fifth lens 250 has a positive refractive power and has a concave object side surface and a convex image side surface. The sixth lens 260 has negative refractive power and has a concave object side surface and a concave image side surface. In addition, the sixth lens 260 has a shape in which an inflection point is formed on at least one of the object side and the image side. The seventh lens 270 has negative refractive power and has a convex object side surface and a concave image side surface. In addition, the seventh lens 270 has a shape in which an inflection point is formed on at least one of the object side and the image side.

The imaging optical system 200 further includes a filter 280, an image sensor 290, and an aperture ST. The filter 280 is disposed between the seventh lens 270 and the image sensor 290, and the diaphragm ST is disposed between the second lens 220 and the third lens 230.

The imaging optical system 200 includes a plurality of lenses having high refractive indices. For example, the second lens 220, the fifth lens 250, and the sixth lens 260 may have a refractive index of 1.6 or more.

The imaging optical system 200 is configured to implement a bright optical system. For example, the F No. of the imaging optical system 200. It is 1.696. The imaging optical system 200 has a wide angle of view. For example, the entire angle of view of the imaging optical system 200 is 78.20 degrees.

In the imaging optical system according to this embodiment, the combined focal length f123 of the first to third lenses is 4.7028 mm, and the combined focal length f4567 of the fourth to seventh lenses is -19.2468 mm.

The imaging optical system configured as above exhibits aberration characteristics as shown in FIGS. 5 and 6 . Table 3 shows the lens characteristics of the imaging optical system according to this embodiment, and Table 4 shows the aspheric surface value of the imaging optical system according to this embodiment.

An imaging optical system according to a third embodiment will be described with reference to FIG. 7 .

The imaging optical system 300 includes a first lens 310, a second lens 320, a third lens 330, a fourth lens 340, a fifth lens 350, a sixth lens 360, and a seventh lens. A lens 370 is included.

The first lens 310 has a positive refractive power, and has a convex object side surface and a concave image side surface. The second lens 320 has negative refractive power and has a convex object side surface and a concave image side surface. The third lens 330 has a positive refractive power and has a convex object side surface and a concave image side surface. The fourth lens 340 has negative refractive power and has a convex object side surface and a concave image side surface. The fifth lens 350 has a positive refractive power, and has a shape in which an object side surface is convex and an image side surface is convex. The sixth lens 360 has negative refractive power and has a concave object side surface and a concave image side surface. In addition, the sixth lens 360 has a shape in which an inflection point is formed on at least one of the object side and the image side. The seventh lens 370 has negative refractive power and has a convex object side surface and a concave image side surface. In addition, the seventh lens 370 has a shape in which an inflection point is formed on at least one of the object side and the image side.

The imaging optical system 300 further includes a filter 380, an image sensor 390, and an aperture ST. The filter 380 is disposed between the seventh lens 370 and the image sensor 390, and the diaphragm ST is disposed between the second lens 320 and the third lens 330.

The imaging optical system 300 includes a plurality of lenses having high refractive indices. For example, the second lens 320, the fifth lens 350, and the sixth lens 360 may have a refractive index of 1.6 or more.

The imaging optical system 300 is configured to implement a bright optical system. For example, the F No. of the imaging optical system 300. It is 1.655. The imaging optical system 300 has a wide angle of view. For example, the total angle of view of the imaging optical system 300 is 78.27 degrees.

In the imaging optical system according to this embodiment, the combined focal length f123 of the first to third lenses is 4.8342 mm, and the combined focal length f4567 of the fourth to seventh lenses is -28.1066 mm.

The imaging optical system configured as above exhibits aberration characteristics as shown in FIGS. 8 and 9 . Table 5 shows lens characteristics of the imaging optical system according to the present embodiment, and Table 6 shows aspheric surface values of the imaging optical system according to the present embodiment.

* An imaging optical system according to a fourth embodiment will be described with reference to FIG. 10 .

The imaging optical system 400 includes a first lens 410, a second lens 420, a third lens 430, a fourth lens 440, a fifth lens 450, a sixth lens 460, and a seventh lens. A lens 470 is included.

The first lens 410 has a positive refractive power, and has a convex object side surface and a concave image side surface. The second lens 420 has negative refractive power and has a convex object side surface and a concave image side surface. The third lens 430 has a positive refractive power and has a convex object side surface and a concave image side surface. The fourth lens 440 has a positive refractive power and has a concave object side surface and a convex image side surface. The fifth lens 450 has negative refractive power, and has a concave object side surface and a convex image side surface. The sixth lens 460 has a positive refractive power and has a convex object side surface and a concave image side surface. In addition, the sixth lens 460 has a shape in which an inflection point is formed on at least one of the object side and the image side. The seventh lens 470 has negative refractive power and has a convex object side surface and a concave image side surface. In addition, the seventh lens 470 has a shape in which an inflection point is formed on at least one of the object side and the image side.

The imaging optical system 400 further includes a filter 480, an image sensor 490, and an aperture ST. The filter 480 is disposed between the seventh lens 470 and the image sensor 490, and the diaphragm ST is disposed between the third lens 430 and the fourth lens 440.

The imaging optical system 400 includes a plurality of lenses having high refractive indices. For example, the second lens 420, the fifth lens 450, and the sixth lens 460 may have a refractive index of 1.6 or more. In other words, the refractive indices of the second lens 420, the fifth lens 450, and the sixth lens 460 may be greater than 1.63 and less than 2.0.

The imaging optical system 400 is configured to implement a bright optical system. For example, the F No. of the imaging optical system 400. It is 1.687. The imaging optical system 400 has a wide angle of view. For example, the total angle of view of the imaging optical system 400 is 78.93 degrees.

In the imaging optical system according to this embodiment, the combined focal length f123 of the first to third lenses is 4.3546 mm, and the combined focal length f4567 of the fourth to seventh lenses is -12.4587 mm.

The imaging optical system configured as above exhibits aberration characteristics as shown in FIGS. 11 and 12 . Table 7 shows the lens characteristics of the imaging optical system according to the present embodiment, and Table 8 shows the aspheric surface values of the imaging optical system according to the present embodiment.

An imaging optical system according to a fifth embodiment will be described with reference to FIG. 13 .

The imaging optical system 500 includes a first lens 510, a second lens 520, a third lens 530, a fourth lens 540, a fifth lens 550, a sixth lens 560, and a seventh lens. Lens 570 is included.

The first lens 510 has a positive refractive power and has a convex object side surface and a concave image side surface. The second lens 520 has negative refractive power and has a convex object side surface and a concave image side surface. The third lens 530 has a positive refractive power and has a convex object side surface and a concave image side surface. The fourth lens 540 has a positive refractive power and has a concave object side surface and a convex image side surface. The fifth lens 550 has negative refractive power and has a concave object side surface and a convex image side surface. The sixth lens 560 has negative refractive power and has a convex object side surface and a concave image side surface. In addition, the sixth lens 560 has a shape in which an inflection point is formed on at least one of the object side and the image side. The seventh lens 570 has negative refractive power and has a convex object side surface and a concave image side surface. In addition, the seventh lens 570 has a shape in which an inflection point is formed on at least one of the object side and the image side.

The imaging optical system 500 further includes a filter 580, an image sensor 590, and an aperture ST. The filter 580 is disposed between the seventh lens 570 and the image sensor 590, and the diaphragm ST is disposed between the second lens 520 and the third lens 530.

The imaging optical system 500 includes a plurality of lenses having high refractive indices. For example, the second lens 520, the fifth lens 550, and the sixth lens 560 may have a refractive index of 1.65 or more.

The imaging optical system 500 is configured to implement a bright optical system. For example, the F No. of the imaging optical system 500. It is 1.783. The imaging optical system 500 has a wide angle of view. For example, the total angle of view of the imaging optical system 500 is 81.67 degrees.

In the imaging optical system according to this embodiment, the combined focal length f123 of the first to third lenses is 4.0082 mm, and the combined focal length f4567 of the fourth to seventh lenses is -8.5519 mm.

The imaging optical system configured as above exhibits aberration characteristics as shown in FIGS. 14 and 15 . Table 9 shows lens characteristics of the imaging optical system according to the present embodiment, and Table 10 shows aspheric surface values of the imaging optical system according to the present embodiment.

Table 11 shows conditional expression values of imaging optical systems according to the first to fifth embodiments.

The present invention is not limited to the embodiments described above, and those skilled in the art can do so without departing from the gist of the technical idea of the present invention described in the claims below. It can be implemented by making various changes. For example, various features described in the above-described embodiment may be applied in combination with other embodiments unless explicitly stated otherwise.

100, 200, 300, 400, 500 imaging optics
110, 210, 310, 410, 510 1st lens
120, 220, 320, 420, 520 2nd lens
130, 230, 330, 430, 530 3rd lens
140, 240, 340, 440, 540 4th lens
150, 250, 350, 450, 550 5th lens
160, 260, 360, 460, 560 6th lens
170, 270, 370, 470, 570 7th lens
180, 280, 380, 480, 580 (infrared cut) filter
190, 290, 390, 490, 590 image sensor or top surface

Claims (15)

a first lens having positive refractive power;
a second lens having negative refractive power, a side surface of the object being convex, and a refractive index of 1.65 or more;
a third lens having refractive power;
a fourth lens having a convex object side surface;
a fifth lens having refractive power;
a sixth lens having a concave image side surface; and
a seventh lens having negative refractive power;
including,
The first lens to the seventh lens are sequentially disposed from the object side, and the following conditional expression is satisfied.
0.65 < f1/f < 1.5
(In the conditional expression, f is the focal length of the imaging optical system, and f1 is the focal length of the first lens) According to claim 1,
The third lens has a positive refractive power. According to claim 1,
The third lens is an imaging optical system having a shape in which an object side surface is convex. According to claim 1,
The third lens has a concave image side surface. According to claim 1,
The fourth lens has negative refractive power. According to claim 1,
An imaging optical system that satisfies the following conditional expression.
1.2 < TL/ImgH < 2.0
(In the above conditional expression, TL is the distance from the object side of the first lens to the image surface, and ImgH is 1/2 of the diagonal length of the image surface) According to claim 1,
An imaging optical system that satisfies the following conditional expression.
1.2 < f3/f < 8.0
(In the conditional expression, f is the focal length of the imaging optical system, and f3 is the focal length of the third lens) According to claim 1,
An imaging optical system that satisfies the following conditional expression.
0.75 < f123 / f < 1.3
(In the above conditional expression, f is the total focal length of the imaging optical system, and f123 is the combined focal length of the first to third lenses.) According to claim 1,
An imaging optical system that satisfies the following conditional expression.
1.1 < |f/f1|+|f/f2| < 2.1
(In the conditional expression, f is the total focal length of the imaging optical system, f1 is the focal length of the first lens, and f2 is the focal length of the second lens) a first lens having positive refractive power;
a second lens having negative refractive power and a refractive index of 1.65 or more;
a third lens having a concave image side surface;
a fourth lens having refractive power;
a fifth lens having negative refractive power and having a concave object side surface and a convex image side surface;
a sixth lens having a concave image side surface; and
a seventh lens having refractive power;
including,
The first lens to the seventh lens are sequentially disposed from the object side, and the following conditional expression is satisfied.
-8.0 < f4567/f < -1.5
(In the above conditional expression, f is the total focal length of the imaging optical system, and f4567 is the combined focal length of the fourth to seventh lenses) According to claim 10,
The third lens has a positive refractive power. According to claim 10,
The sixth lens has a positive refractive power. According to claim 10,
The seventh lens has negative refractive power. According to claim 10,
An imaging optical system that satisfies the following conditional expression.
-0.75 < f1/f2 < -0.3
(In the conditional expression, f1 is the focal length of the first lens, and f2 is the focal length of the second lens) According to claim 10,
An imaging optical system that satisfies the following conditional expression.
0.65 < ImgH/f
(In the above conditional expression, ImgH is 1/2 of the diagonal length of the upper surface)

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