KR20170133795A - Lens Module - Google Patents

Abstract

The present invention relates to a lens module. The lens module according to an embodiment of the present invention includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged in order from an object side to an image side. The first lens has a negative refractive power, a convex object side, and a concave image side. The second lens has a positive refractive power, a convex object side, and a convex image side. The third lens and the fourth lens have a refractive power. The fifth lens has a refractive power, a concave object side, and a convex image side. The object side of the fifth lens has two or more inflection points when viewed from a cross section including an optical axis. The sixth lens has a negative refractive power, a concave object side, and a convex image side.

Description

A lens module {Lens Module}

The present invention relates to a lens module, and more particularly, to a lens module having a micro-optical system which is composed of six lenses and can realize a high resolution high angle of view.

Generally, a camera for a portable terminal includes a lens module and an imaging device.

Here, the lens module includes a plurality of lenses and constitutes an optical system for projecting images of a plurality of lens subjects onto an image pickup element. An element such as a CCD is used as the imaging element, and typically has a pixel size of 1.4 μm or more.

However, as the size of the portable terminal and the size of the camera gradually become smaller, the pixel size of the image pickup device is reduced to 1.12 μm or less, and accordingly, a lens module having a low F number of 2.3 or less Is required.

KR10-1504033 B1 KR10-1504062 B1 KR10-1452150 B1 US8743483 B2

SUMMARY OF THE INVENTION It is an object of the present invention to provide a miniature lens module having a high resolution and a wide angle of view.

A lens module according to an embodiment of the present invention includes a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged in order from the object side to the image side, 1 lens has negative refracting power, and has a convex object side and a concave upper side, the second lens has positive refracting power, has a convex object side and a convex upper side, and the third lens and the fourth lens have a refracting power Wherein the fifth lens has a refracting power, has a concave object side and a convex upper side, the object side of the fifth lens has two or more inflection points when viewed from a cross section including an optical axis, Has a concave object side surface and a convex image side surface, and satisfies the following expression (1).

[Equation 1] -35 <f ₁ / f <-16

Here, f is the focal length of the entire lens module, and f ₁ is the focal length of the first lens.

The object side surface of the fifth lens may include an inflection point formed at a predetermined distance from the optical axis.

The following expression (2) can be satisfied.

[Formula 2] | f ₅ / f | > 80

Here, f is the focal length of the entire lens module, and f ₅ is the focal length of the fifth lens.

The concave object side surface of the sixth lens may include a first curved portion formed on the optical axis and a second curved portion formed at a position separated from the optical axis by a predetermined distance.

The convex upper surface of the sixth lens may include a concave portion formed on the optical axis.

The fourth lens has a positive refractive power and may have a concave object side surface and a convex upper side surface.

The following expression (3) can be satisfied.

[Formula 3] V ₁ - V ₃ > 25

Here, V ₁ is the Abbe number of the first lens, and V ₃ is the Abbe number of the third lens.

The following expression (4) can be satisfied.

[Formula 4] V ₆ - V ₅ > 34

Here, V ₆ is the Abbe number of the sixth lens, and V ₅ is the Abbe number of the fifth lens.

The following expression (5) can be satisfied.

[Equation 5] FOV / T > 15

Here, FOV is the angle of view of the lens module, and T is the distance from the object side to the image plane of the first lens.

The following expression (6) can be satisfied.

[Formula 6] (R _1a - R _1b ) / (R _1a + R _1b ) <0.1

Here, R _1a is the radius of curvature of the object side surface of the first lens, and R _1b is the radius of curvature of the upper surface of the first lens.

The inflection point of the fifth lens is located at a distance of 0.6 to 0.9 mm from the center of the optical axis, and can satisfy the following expression (7).

[Formula 7] -6 < ( _R5a - _R5b ) / ( _R5a + _R5b ) < 0.2

Here, R _5a is the radius of curvature of the object side surface of the fifth lens, and R _5b is the radius of curvature of the image surface of the fifth lens.

The following Expression 8 can be satisfied.

[Equation 8] -25 <f ₁ / T <-10

Here, f ₁ is the focal length of the first lens, and T is the distance from the object side surface of the first lens to the image surface.

The following expression (9) can be satisfied.

[Equation 9] 70 <| f ₅ / T | <250

Where, f ₅ is the focal length of the fifth lens, T is the distance to the surface at the object side of the first lens.

A diaphragm may be disposed in the object side direction of the first lens.

According to the present invention, it is possible to provide a very small lens module having a high resolution and a wide angle of view.

1 is a lens configuration diagram according to a first embodiment of the present invention.
FIG. 2 is a graph of a modulation transfer function (MTF) of the first embodiment of FIG.
3 is an aberration graph of the first embodiment of Fig.
4 is a lens configuration diagram according to a second embodiment of the present invention.
5 is an MTF graph of the second embodiment of FIG.
6 is an aberration graph of the second embodiment of Fig.
7 is a lens configuration diagram according to the third embodiment of the present invention.
8 is an MTF graph of the third embodiment of FIG.
9 is an aberration graph of the third embodiment of Fig.

These embodiments are capable of various modifications and various embodiments, and specific embodiments will be described in detail with reference to the drawings. It is to be understood, however, that it is not intended to limit the scope of the specific embodiments but includes all transformations, equivalents, and alternatives falling within the spirit and scope of the disclosure disclosed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In the following description of the embodiments of the present invention,

The lens modules according to the first, second and third embodiments of non-limiting and exemplary embodiments of the present invention are shown in Figs. 1, 4 and 7. Fig. Hereinafter, the first embodiment of FIG. 1 will be described as a reference, but the description of the configuration and characteristics of each lens is also applied to other embodiments. However, it should be understood that the present invention is not limited thereto and may be changed depending on specific application conditions.

1 showing a lens configuration according to a first embodiment of the present invention, a lens module according to an embodiment of the present invention includes a first lens 11 arranged in order from the object side to an image side, A third lens 13, a fourth lens 14, a fifth lens 15, and a sixth lens 16, as shown in FIG.

The lens module according to the present invention may include an imaging optical system composed of six lenses. That is, the lens module may be composed of the first lens to the sixth lens. However, the lens module does not consist of only six lenses, and may further include other components as needed. For example, the lens module may further include a stop S for adjusting the amount of light. Further, an image surface IP including the optical filter IF and the image sensor may be sequentially formed in the upward direction of the sixth lens.

Accordingly, the image of the object is formed so as to be incident on the image surface IP on which the image sensor is disposed via the first to sixth lenses. The image sensor may include a Charged Coupled Device (CCD) and a Complementary Metal-Oxide Semiconductor (CMOS), but the present invention is not limited thereto, and various images Sensors can be applied.

The first to sixth lenses may be made of a plastic material or a glass material. In addition, at least one of the first to sixth lenses may include one or more aspherical surfaces to minimize aberration.

1, the first lens 11 is formed to have a convex object side surface 11a and a concave upper side surface 11b, which have a negative refractive power. Since the first lens 11 is formed to have a negative refractive power, the field of view of the entire lens can be enlarged. Since the first lens 11 has a negative refractive power, the incident light is minimized to pass through the lens module. The higher the value of the negative refractive index of the first lens 11, the wider the angle of view, but if it is too wide, the aberration correction becomes difficult.

Specifically, the first lens 11 is formed so as to satisfy the following expression (1).

[Equation 1] -35 <f ₁ / f <-16

Here, f is the focal length of the entire lens module, and f ₁ is the focal length of the first lens. [Equation 1] is a value representing the ratio of the focal length of the first lens to the focal length of the entire lens module. When the upper limit value is exceeded, it is difficult to secure a desired angle of view (FOV). When the lower limit value is exceeded, the refractive power of the lens becomes excessively large, and aberration correction becomes difficult.

Further, the first lens 11 can satisfy the following expression (6).

[Formula 6] (R _1a - R _1b ) / (R _1a + R _1b ) <0.1

Here, R _1a is the radius of curvature of the object side surface 11a of the first lens 11, and R _1b is the radius of curvature of the image side surface 11b of the first lens 11. The ratio of the radius of curvature of the first lens 11a as described above can be a condition for optimizing the shape of the first lens 11a.

Further, the first lens 11 can satisfy the following expression (8).

[Equation 8] -25 <f ₁ / T <-10

Here, f ₁ is the focal length of the first lens and T is the distance from the object side surface 11a of the first lens 11 to the surface on which the image is formed, that is, the top surface IP. T denotes the total length of the optical system constituting the lens module, and the smaller the T value, the smaller the optical system can be realized.

However, a smaller T value limits the number of lenses that can be included, and aberration correction becomes more difficult as the number of lenses is limited. The ratio of the focal length of the first lens to the total length of the entire optical system may be a condition for optimizing the performance of the first lens in the lens module including six lenses and when the upper limit value is exceeded, If it is less than the lower limit value, the refractive index becomes too large and the aberration characteristic may be deteriorated.

The second lens 12 has a positive refractive power and is formed to have a convex object side face 12a and a convex upper side face 12b. The second lens 12 is formed to collect light.

The third lens 13 is formed to have a refractive power, and is formed to have a negative refractive power, and is formed to include a concave object side surface 13a and a convex upper side surface 13b. The third lens 13 serves to correct the aberration of the image.

The third lens 13 can satisfy the following expression (3).

[Formula 3] V ₁ - V ₃ > 25

Here, V ₁ is the Abbe number of the first lens 11, and V ₃ is the Abbe number of the third lens 13. The Abbe number is a condition defining the material of each lens, and by satisfying the above condition, the aberration of the optical system can be minimized.

Further, the third lens 13 may be made of a material having a refractive index of 1.6 or more. Since the lens is made of a material having a high refractive index, a lens having a high refractive index with a small thickness can be provided.

The fourth lens 14 is formed to have a refractive power, preferably has a positive refractive power, and may have a concave object side surface 14a and a convex upper side surface 14b. The fourth lens can minimize the chromatic aberration by lowering the photoelectric sensitivity of the lens module.

The fifth lens 15 has a refracting power, has a concave object side and a convex upper side, and the object side of the fifth lens has two or more inflection points when viewed from a cross section including an optical axis. The fifth lens 15 may be formed to have a positive or negative refractive index, and the refractive index of the fifth lens 15 may optimize the astigmatism characteristic.

The fifth lens 15 can satisfy the following expression (2).

[Formula 2] | f ₅ / f | > 80

Here, f is the focal length of the entire lens module, and f ₅ is the focal length of the fifth lens. The above equation is used to reduce the lens module, and if it is less than the lower limit value, the astigmatism characteristic may be deteriorated.

Further, the following expression (9) can be satisfied.

[Equation 9] 70 <| f ₅ / T | <250

Where, f ₅ is the focal length of the fifth lens, T is the distance to the surface on which image is formed on the object-side surface of the first lens. The above equation is a condition for optimizing the performance and shape of the fifth lens with respect to the total electric field. When the upper limit value is exceeded, the aberration characteristic deteriorates. When the lower limit value is less than the lower limit value, miniaturization of the lens module becomes difficult .

Referring to FIG. 1, the object side 15a of the fifth lens 15 may include inflection points P1 and P2 formed at a position separated from the optical axis X by a predetermined distance.

In the present specification, the inflection points P1 and P2 refer to a point at which the radius of curvature is changed, and are described based on a view in a section including the optical axis X. [ That is, in the three-dimensional shape of the fifth lens 15, the two inflection points in Fig. 1 are formed to have a circular shape disposed at a predetermined distance from the optical axis.

The inflection point of the fifth lens 15 may be located 0.6 to 0.9 mm from the center of the optical axis. As a condition for optimizing the shape of the fifth lens 15, when the upper limit value is exceeded, the size of the lens becomes larger, and when it is lower than the lower limit value, it is difficult to secure a desired refractive index.

The fifth lens 15 can satisfy the following expression (7).

[Formula 7] -6 < ( _R5a - _R5b ) / ( _R5a + _R5b ) < 0.2

Here, R _5a is the radius of curvature of the object side surface of the fifth lens, and R _5b is the radius of curvature of the upper surface of the fifth lens.

The curvature radius condition of the fifth lens together with the position of the inflection point may be a condition for optimizing the refractive index and size of the fifth lens.

The sixth lens 16 may have a negative refractive power and may have a concave object side surface 16a and a convex upper side surface 16b. The concave object side surface 16a of the sixth lens 16 has a first curved portion P4 formed on the optical axis X and a second curved portion P3 formed on the optical axis X at a predetermined distance, P4).

The first curved portion P4 is a convex point formed on the optical axis in the three-dimensional shape of the sixth lens 16 and the second curved portions P3 and P4 are convex in the form of a ring around the optical axis Lt; / RTI &gt;

The convex upper surface 16b of the sixth lens 16 may include a concave portion P6 formed on the optical axis X. [

The shape of the sixth lens 16 as described above is for optimizing the aberration characteristics of the optical system and the sixth lens 16 can satisfy the following expression 4 in relation to the fifth lens 15.

[Formula 4] V ₆ - V ₅ > 34

Here, V ₆ is the Abbe number of the sixth lens 16, and V ₅ is the Abbe number of the fifth lens 16. The Abbe number is a condition defining the material of each lens, and by satisfying the above condition, the aberration of the optical system can be minimized.

According to various embodiments of the present invention, it is possible to provide a lens module having a wide angle of view and excellent resolution. In addition, a very small lens module can be provided.

Specifically, the lens module of the present invention can satisfy [Expression 5].

[Equation 5] FOV / T > 15

Here, FOV is the angle of view of the lens module, and T is the total length of the lens module. The smaller the value, the smaller the lens module or the angle of view, and the larger the value, the smaller the lens module and the larger the angle of view. If it is less than the lower limit value, the desired angle of view can not be realized in the six lens modules.

In the case of the present invention, it is possible to realize a lens module having a wide angle of view of about 80 degrees or more even in the case of an overall length of 4.85 mm or less, thereby realizing a lens module having excellent performance.

According to an embodiment of the present invention, the diaphragm S may be disposed on the object side surface 11a of the first lens 11. The structure of the optical system may vary depending on the position of the diaphragm. By disposing the stop S in front of the object side surface 11a of the first lens 11 in the optical system structure of the present invention, the aberration, the angle of view, and the MTF characteristic can be optimized.

Hereinafter, the structure and effects of the present invention will be described in more detail through concrete examples.

The aspherical surface used in each of the following examples represents the Conic constant K and the aspheric coefficients A, B, C, D, E, F, and G obtained from the known [Expression 10]. And "E and the following number" in the numbers represent the power of 10. For example, E-05 10 ^- represents a ^5.

[Equation 10]

Z: Distance from the lens apex to the optical axis direction

)R: Distance in the direction perpendicular to the optical axis (

)

)α: the reciprocal of the radius of curvature at the apex of the lens (

)

K: Kornic constant

A, B, C, D, E, F, G: Aspherical surface coefficient

The following [Table 1] to [Table 3] show numerical examples of the lens module of the first embodiment of the present invention. The lens module of the first embodiment includes a first lens 11, a second lens 12, a third lens 13, a fourth lens 14, a fifth lens 15 and a sixth lens 16 And the optical filter IF and the top face IP are sequentially formed on the upper side. A diaphragm S is disposed in front of the object side surface 11a of the first lens 11.

The face numbers below refer to face numbers of the lenses shown in Fig. In the following Table 1, * denotes an aspherical surface, and Table 2 shows the conic constant and aspherical surface coefficients of the first lens 11 to the sixth lens 16.

In the present specification, the unit of radius of curvature R, thickness t, and focal length f is mm.

Referring to FIG. 1, the first lens 11 includes a convex object side surface 11a and a concave upper surface side 11b with a negative refractive power. The second lens 12 has a convex object side 12a and a convex upper side 12b with a positive refractive power. The third lens 13 has a negative refractive power, and has a concave object side surface 13a and a concave upper side surface 13b. The fourth lens 14 has a positive refractive power and has a concave object side surface 14a and a convex upper side surface 14b. The fifth lens 15 has a negative refracting power and has a concave object side surface 15a and a convex upper surface 15b. It has two inflection points when viewed in cross section at a position spaced apart from the optical axis X by a predetermined interval. The sixth lens has a negative refracting power and has a concave object side surface 16a and a convex upper side surface 16b when viewed as a whole. The object side surface 16a is provided with three curved portions on the basis of a cross section, ) Includes one concave portion.

The case of the first embodiment, and F _no is 2, field of view (FOV) is 80.43 degrees. Referring to [Table 3], it can be seen that the first embodiment satisfies [Expression 1] to [Expression 9] in the detailed description.

That is, it can be seen that, in the case of the first embodiment, a lens module having excellent optical characteristics is provided. It can be seen that a lens module having excellent optical characteristics is provided while realizing a short optical system.

2 is an MTF graph of the first embodiment, in which an image is divided into a plurality of sections and an MTF graph of each section is expressed. As the spatial frequency in each section increased, the response decreased to a relatively gentle slope. In the case of the first embodiment, it can be seen that the response is as low as about 0.1 at the final spatial frequency, resulting in a relatively clear image.

3 is a graph showing spherical aberration, astigmatism, and distortion aberration of the first embodiment. Referring to FIG. 3, it can be seen that the first embodiment provides a lens module having various aberration characteristics.

The following [Table 4] to [Table 6] show numerical examples of the lens module of the second embodiment of the present invention. The lens module of the second embodiment includes a first lens 21, a second lens 22, a third lens 23, a fourth lens 24, a fifth lens 25 and a sixth lens 26 And the optical filter IF and the top face IP are sequentially formed on the upper side. A diaphragm S is disposed in front of the object side surface 21a of the first lens 21.

The face number below refers to the face number of the lenses shown in Fig. In Table 4, * denotes an aspherical surface, and Table 5 shows the conic constant and aspherical surface coefficients of the first lens 21 to the sixth lens 26. [

Referring to FIG. 4, the first lens 21 includes a convex object side surface 21a and a concave upper surface side 21b with a negative refractive power. The second lens 22 has a convex object side surface 22a and a convex upper side surface 22b with a positive refractive power. The third lens 23 has a negative refractive power and has a concave object side surface 23a and a concave upper side surface 23b. The fourth lens 24 has a positive refractive power and has a concave object side surface 24a and a convex upper side surface 24b. The fifth lens 25 has a positive refractive power and has a concave object side surface 25a and a convex upper side surface 25b. It has two inflection points when viewed in cross section at a position spaced apart from the optical axis X by a predetermined interval. The sixth lens has a negative refracting power and has a concave object side surface 26a and a convex upper side surface 26b when viewed as a whole. Three curved portions are formed on the object side surface 26a, ) Includes one concave portion.

The case of the first embodiment, and F _no is 2.13, angle of view (FOV) is 79.82 degrees. Referring to Table 6, it can be seen that the second embodiment satisfies [Expression 1] to [Expression 9] in the detailed description.

That is, in the case of the second embodiment, it can be seen that a lens module with excellent optical characteristics is provided. It can be seen that a lens module having excellent optical characteristics is provided while realizing a short optical system.

5 is an MTF graph of the second embodiment, in which an image is divided into a plurality of sections and an MTF graph of each section is expressed. As the spatial frequency in each section increased, the response decreased to a relatively gentle slope. In the case of the second embodiment, it can be seen that the response is as low as about 0.1 at the final spatial frequency, resulting in a relatively clear image.

6 is a graph showing spherical aberration, astigmatism, and distortion aberration of the second embodiment. Referring to FIG. 6, it can be seen that the second embodiment provides a lens module having various aberration characteristics.

The following [Table 7] to [Table 9] show numerical examples of the lens module of the third embodiment of the present invention. The lens module of the third embodiment includes a first lens 31, a second lens 32, a third lens 33, a fourth lens 34, a fifth lens 35 and a sixth lens 36 And the optical filter IF and the top face IP are sequentially formed on the upper side. A diaphragm S is disposed in front of the object side surface 31a of the first lens 31. [

The face numbers below refer to the face numbers of the lenses shown in Fig. In Table 4 below, * denotes an aspherical surface, and Table 8 shows the conic constant and aspherical surface coefficients of the first lens 31 to the sixth lens 36.

Referring to FIG. 7, the first lens 31 includes a convex object side surface 31a and a concave upper surface side 31b with a negative refractive power. The second lens 32 has a convex object side surface 32a and a convex upper side surface 32b with a positive refractive power. The third lens 33 has a negative refracting power and has a concave object side surface 33a and a concave upper surface 33b. The fourth lens 34 has a positive refractive power and has a concave object side surface 34a and a convex upper side surface 34b. The fifth lens 35 has a positive refractive power and has a concave object side 35a and a convex upper side 35b. It has two inflection points when viewed in cross section at a position spaced apart from the optical axis X by a predetermined interval. The sixth lens has a negative refracting power and has a concave object side surface 36a and a convex upper side surface 36b when viewed as a whole. The object side surface 36a is provided with three curved portions, ) Includes one concave portion.

The case of the first embodiment, and F _no is 2.13, angle of view (FOV) is 83.71 degrees. Referring to Table 9, it can be seen that the third embodiment satisfies [Expression 1] to [Expression 9] in the detailed description.

That is, it can be seen that, in the case of the third embodiment, a lens module having excellent optical characteristics is provided. It can be seen that a lens module having excellent optical characteristics is provided while realizing a short optical system.

FIG. 8 is an MTF graph of the third embodiment, in which an image is divided into several sections and an MTF graph for each section is expressed. As the spatial frequency in each section increased, the response decreased to a relatively gentle slope. In the case of the third embodiment, it can be seen that the response is as low as about 0.1 at the final spatial frequency, resulting in a relatively clear image.

9 is a graph showing spherical aberration, astigmatism, and distortion aberration of the third embodiment. Referring to FIG. 9, it can be seen that the third embodiment provides a lens module having various aberration characteristics.

X: optical axis
11, 21, 31: a first lens
12, 22, 32: a second lens
13, 23, 33: Third lens
14, 24, 34: fourth lens
15, 25, 35: first lens
16, 26, 36: a first lens
IF: Optical filter
IP: Top

Claims (14)

A first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens arranged in order from the object side to the image side,
Wherein the first lens has a negative refracting power and has a convex object side and a concave upper side,
The second lens has a positive refractive power, has a convex object side and a convex upper side,
The third lens and the fourth lens have a refractive power,
Wherein the fifth lens has a refracting power, has a concave object side and a convex upper side, the object side of the fifth lens has two or more inflection points when viewed from a cross section including an optical axis,
Wherein the sixth lens has a negative refractive power and has a concave object side and a convex upper side, and satisfies the following expression (1).
[Equation 1] -35 <f ₁ / f <-16
Here, f is the focal length of the entire lens module, and f ₁ is the focal length of the first lens.
The method according to claim 1,
Wherein an object side surface of the fifth lens includes an inflection point formed at a position spaced a predetermined distance from the optical axis.
The method according to claim 1,
Satisfies the following expression (2).
[Formula 2] | f ₅ / f | > 80
Here, f is the focal length of the entire lens module, and f ₅ is the focal length of the first lens.
The method according to claim 1,
Wherein the concave object side surface of the sixth lens includes a first curved portion formed on the optical axis and a second curved portion formed at a position separated from the optical axis by a predetermined distance.
The method according to claim 1,
And the convex upper side of the sixth lens includes a concave portion formed on the optical axis.
The method according to claim 1,
And the fourth lens has a positive refractive power and has a concave object side surface and a convex upper side surface.
The method according to claim 1,
Satisfies the following expression (3).
[Formula 3] V ₁ - V ₃ > 25
Here, V ₁ is the Abbe number of the first lens, and V ₃ is the Abbe number of the third lens.
The method according to claim 1,
Satisfies the following expression (4).
[Formula 4] V ₆ - V ₅ > 34
Here, V ₆ is the Abbe number of the sixth lens, and V ₅ is the Abbe number of the fifth lens.
The method according to claim 1,
And satisfies the following expression (5).
[Equation 5] FOV / T > 15
Here, FOV is the angle of view of the lens module, and T is the distance from the object side to the image plane of the first lens.
The method according to claim 1,
(6): &quot; (6) &quot;
[Formula 6] (R _1a - R _1b ) / (R _1a + R _1b ) <0.1
Here, R _1a is the radius of curvature of the object side surface of the first lens, and R _1b is the radius of curvature of the upper surface of the first lens.
The method according to claim 1,
Wherein an inflection point of the fifth lens is located at a distance of 0.6 to 0.9 mm from the center of the optical axis, and satisfies the following expression (7).
_R5a - _R5b / _R5a + _R5b < 0.2 <
Here, R _5a is the radius of curvature of the object side surface of the fifth lens, and R _5b is the radius of curvature of the image surface of the fifth lens.
The method according to claim 1,
And satisfies the following expression (8).
[Equation 8] -25 <f ₁ / T <-10
Here, f ₁ is the focal length of the first lens, and T is the distance from the object side surface of the first lens to the image surface.
The method according to claim 1,
Satisfies the following expression (9).
[Equation 9] 70 <| f ₅ / T | <250
Where, f ₅ is the focal length of the fifth lens, T is the distance to the surface at the object side of the first lens.
The method according to claim 1,
And a diaphragm is disposed in a direction of an object side surface of the first lens.

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