KR102257745B1 - Imaging Lens System - Google Patents

Abstract

The optical system according to the present invention includes: a first lens having a concave image side; A second lens having refractive power; A third lens having a convex object side surface; A fourth lens having a concave image side surface; A fifth lens having refractive power; And a sixth lens having refractive power and having an inflection point formed on the image side.

Description

Imaging Optical System {Imaging Lens System}

The present invention relates to an optical system having a wide angle of view.

Small cameras are mounted on wireless terminals. For example, in a small camera, a wireless terminal is mounted on the front and rear sides, respectively. Since such a small camera is used for various purposes such as outdoor landscape photography and indoor portrait photography, performance comparable to that of general cameras is required. However, since the overall length of the high-performance small camera becomes longer, there is a problem that it protrudes to the surface of the wireless terminal. Accordingly, there is a need to develop an optical system capable of improving the performance of the small camera without increasing the overall length of the small camera.

For reference, there are Patent Documents 1 to 3 as prior art related to the present invention.

KR 10-1429890 B1 US 2015-0098135 A1 US 2016-0147044 A1

The present invention is to solve the above problems, and an object thereof is to provide an optical system capable of being mounted on a thin wireless terminal.

An optical system according to an embodiment of the present invention for achieving the above object includes: a first lens having a concave image side; A second lens having refractive power; A third lens having a convex object side surface; A fourth lens having a concave image side surface; A fifth lens having refractive power; And a sixth lens having refractive power and having an inflection point formed on the image side.

The present invention can provide an optical system that can be mounted on a thin wireless terminal and has a wide angle of view.

1 is a configuration diagram of an optical system according to a first embodiment of the present invention
2 is an aberration curve of the optical system shown in FIG. 1
3 is a configuration diagram of an optical system according to a second embodiment of the present invention
4 is an aberration curve of the optical system shown in FIG. 3
5 is a configuration diagram of an optical system according to a third embodiment of the present invention
6 is an aberration curve of the optical system shown in FIG. 5
7 is a configuration diagram of an optical system according to a fourth embodiment of the present invention
8 is an aberration curve of the optical system shown in FIG. 7
9 is a front view of a wireless terminal equipped with an optical system of the present invention
10 is a rear view of the wireless terminal shown in FIG. 9
11 is an II cross-sectional view of FIG. 10

Hereinafter, a preferred embodiment of the present invention will be described in detail on the basis of the accompanying exemplary drawings.

In the following description of the present invention, terms referring to the constituent elements of the present invention are named in consideration of the functions of the respective constituent elements, and thus, should not be understood as limiting the technical constituents of the present invention.

In addition, throughout the specification, that a certain configuration is'connected' to another configuration includes not only the case where these configurations are'directly connected', but also the case where the other configurations are'indirectly connected'. 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 means the lens closest to the object (or subject), and the seventh lens means the lens closest to the image surface (or image sensor). In the present specification, units of the lens' curvature radius (Radius), thickness (Thickness), TL (distance from the object side of the first lens to the image surface), Y (half the diagonal length of the image surface), and the focal length are mm.

The thickness of the lens, the distance between the lenses, and TL are the distances in the optical axis of the lens. In addition, in the description of the shape of the lens, the meaning that one side is convex means that the paraxial region of the surface is convex, and the meaning that the one side is concave means that the paraxial portion of the corresponding surface is concave. Therefore, even if it is described that one surface of the lens is convex, the edge portion of the lens may be concave. Similarly, even if it is described that one surface of the lens is concave, the edge portion of the lens may be convex.

The optical system includes 6 lenses. For example, the optical system may include a first lens, a second lens, a third lens, a fourth lens, a fifth lens, and a sixth lens that are sequentially disposed from the object side.

The first lens has refractive power. For example, the first lens has negative refractive power. The first lens has a concave shape. For example, the first lens has a concave image side.

The first lens includes an aspherical 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 processability. For example, the first lens may be made of a plastic material.

The second lens has refractive power. For example, the second lens has positive refractive power. The second lens has a convex shape. For example, the second lens may have a convex object side.

The second lens includes an aspherical surface. For example, the second lens may have an aspherical surface. The second lens may be made of a material having high light transmittance and excellent processability. For example, the second lens may be made of a plastic material. The second lens has a different refractive index than the first lens. For example, if the refractive index of the first lens is less than 1.6, the refractive index of the second lens may be 1.65 or more. As another example, if the refractive index of the first lens is 1.6 or more, the refractive index of the second lens may be less than 1.6.

The third lens has refractive power. For example, the third lens may have positive or negative refractive power. The third lens has a convex shape. For example, the third lens may have a convex object side.

The third lens includes an aspherical surface. For example, the image side of the third lens may be an aspherical surface. The third lens may be made of a material having high light transmittance and excellent processability. 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, when the refractive index of the first lens is less than 1.6, the refractive index of the third lens is less than 1.6, and when the refractive index of the first lens is 1.6 or more, the refractive index of the third lens may also be 1.6 or more.

The fourth lens has refractive power. For example, the fourth lens has positive or negative refractive power. The fourth lens has a concave shape. For example, the fourth lens may have a concave image side.

The fourth lens includes an aspherical 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 processability. For example, the fourth lens may be made of a plastic material. The fourth lens may have a generally high refractive index. For example, the refractive index of the fourth lens may be 1.6 or higher.

The fifth lens has refractive power. For example, the fifth lens may have positive refractive power. The fifth lens has a concave shape. For example, the fifth lens may have a concave object side.

The fifth lens includes an aspherical 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 processability. For example, the fifth lens may be made of a plastic material. The fifth lens has a lower refractive index than that of the fourth lens. For example, the refractive index of the fifth lens may be less than 1.6.

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

The sixth lens includes an aspherical 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 processability. 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 fourth lens. For example, the refractive index of the sixth lens may be 1.6 or more.

Aspherical surfaces of the first to sixth 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 any point on the aspherical surface to the optical axis, A to J are aspherical surface constants, and Z (or SAG) is aspherical surface It is the height in the optical axis direction from an arbitrary point on the image to the vertex of the aspherical surface.

The optical system further includes a filter, an image sensor, and an aperture stop.

The filter is disposed between the sixth lens and the image sensor. Filters can block some wavelengths of light. For example, the filter can block light in infrared wavelengths.

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

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

The optical system may satisfy the following conditional expressions.

[Conditional Expression 1] -35 <{(1/f)*(Y/tanθ)-1}*100 <-5.0

[Conditional Expression 2] TL/(2Y) ≤ 1.01

[Conditional Equation 3] 0.3 <R2/f <2.0

[Conditional Expression 4] 0.3 <(R1+R2)/(R1-R2) <3.0

[Conditional Expression 5] -1.5 <f/f1 <-0.05

[Conditional Expression 6] 0.1 <|f/f3| <2.0

[Conditional Expression 7] 0.3 <|f/f6| <1.8

[Conditional Equation 8] 1.2 ≤ tanθ

[Conditional Expression 9] 1.8 <f/EPD <2.4

[Conditional Expression 10] 0.4 <(t1+t2)/t3 <2.0

[Conditional Expression 11] 30 ≤ V5-V6 <40

In the above conditional expression, f is the total focal length of the imaging optical system, 2Y is the diagonal length of the image plane, Y is 1/2 of the 2Y, θ is the half-view angle of the imaging optical system, and TL is from the object side to the image plane of the first lens. Is the distance of, R1 is the radius of curvature of the object side of the first lens, R2 is the radius of curvature of the image side of the first lens, f1 is the focal length of the first lens, f2 is the focal length of the second lens, f3 is the focal length of the third lens, f6 is the focal length of the sixth lens, EPD is the diameter of the entrance pupil, t1 is the thickness at the optical axis portion of the first lens, and t2 is the optical axis portion of the second lens. Is the thickness, t3 is the thickness at the optical axis portion of the third lens, V5 is the Abbe number of the fifth lens, and V6 is the Abbe number of the sixth lens.

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

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

The optical system 100 includes a first lens 110, a second lens 120, a third lens 130, a fourth lens 140, a fifth lens 150, and a sixth lens 160. .

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

The optical system 100 further includes a filter 170, an image sensor 180, and a stop ST. The filter 170 is disposed between the sixth lens 160 and the image sensor 180, and the stop ST is disposed between the second lens 120 and the third lens 130.

The optical system 100 includes a plurality of lenses having a large refractive index. For example, the second lens 120, the fourth lens 140, and the sixth lens 160 may have a refractive index of 1.6 or more. To further explain, the refractive indexes of the second lens 120, the fourth lens 140, and the sixth lens 160 may be greater than 1.62 and less than 2.0.

The optical system 100 is configured to have a wide angle of view. For example, the half-view angle of the imaging optical system 100 is 60.43 degrees.

The optical system configured as described above exhibits aberration characteristics as shown in FIG. 2. Table 1 shows the lens characteristics of the optical system according to the present embodiment, and Table 2 shows the aspherical values of the optical system according to the present embodiment.

An optical system according to a second embodiment will be described with reference to FIG. 3.

The optical system 200 includes a first lens 210, a second lens 220, a third lens 230, a fourth lens 240, a fifth lens 250, and a sixth lens 260. .

The first lens 210 has negative refractive power and has a convex object side and a concave image side. The second lens 220 has positive refractive power, and has a convex object side and a concave image side. The third lens 230 has positive refractive power, and has a convex object side surface and a convex image side surface. The fourth lens 240 has negative refractive power, and has a convex object side and a concave image side. The fifth lens 250 has 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 convex 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 an object side and an image side.

The optical system 200 further includes a filter 270, an image sensor 280, and a stop ST. The filter 270 is disposed between the sixth lens 260 and the image sensor 280, and the stop ST is disposed between the second lens 220 and the third lens 230.

The optical system 200 includes a plurality of lenses having a large refractive index. For example, the second lens 220, the fourth lens 240, and the sixth lens 260 may have a refractive index of 1.6 or more. To further explain, the refractive indexes of the second lens 220, the fourth lens 240, and the sixth lens 260 may be greater than 1.62 and less than 2.0.

The optical system 200 is configured to have a wide angle of view. For example, the half-view angle of the imaging optical system 200 is 60.03 degrees.

The optical system configured as described above exhibits aberration characteristics as shown in FIG. 4. Table 3 shows the lens characteristics of the optical system according to the present embodiment, and Table 4 shows the aspherical values of the optical system according to the present embodiment.

An optical system according to a third embodiment will be described with reference to FIG. 5.

The optical system 300 includes a first lens 310, a second lens 320, a third lens 330, a fourth lens 340, a fifth lens 350, and a sixth lens 360. .

The first lens 310 has negative refractive power, and has a concave object side and a concave image side. The second lens 320 has positive refractive power, and has a convex object side and a concave image side. The third lens 330 has positive refractive power, and has a convex object side and a convex image side. 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 positive refractive power, and has a concave object side surface and a convex image side surface. The sixth lens 360 has negative refractive power, and has a convex 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 an object side and an image side.

The optical system 300 further includes a filter 370, an image sensor 380, and a stop ST. The filter 370 is disposed between the sixth lens 360 and the image sensor 380, and the stop ST is disposed between the second lens 320 and the third lens 330.

The optical system 300 includes a plurality of lenses having a large refractive index. For example, the second lens 320, the fourth lens 340, and the sixth lens 360 may have a refractive index of 1.6 or more. To further explain, the refractive indexes of the second lens 320, the fourth lens 340, and the sixth lens 360 may be greater than 1.62 and less than 2.0.

The optical system 300 is configured to have a wide angle of view. For example, the half-view angle of the optical system 300 is 60.42 degrees.

The optical system configured as described above exhibits aberration characteristics as shown in FIG. 6. Table 5 shows the lens characteristics of the optical system according to the present embodiment, and Table 6 shows the aspherical values of the optical system according to the present embodiment.

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

The optical system 400 includes a first lens 410, a second lens 420, a third lens 430, a fourth lens 440, a fifth lens 450, and a sixth lens 460. .

The first lens 410 has negative refractive power and has a convex object side and a concave image side. The second lens 420 has positive refractive power, and has a convex object side surface and a convex image side surface. The third lens 430 has negative refractive power, and has a convex object side surface and a concave image side surface. The fourth lens 440 has positive refractive power, and has a convex object side surface and a concave image side surface. The fifth lens 450 has positive refractive power, and has a concave object side surface and a convex image side surface. The sixth lens 460 has negative 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 an object side and an image side.

The optical system 400 further includes a filter 470, an image sensor 480, and a stop ST. The filter 470 is disposed between the sixth lens 460 and the image sensor 480, and the stop ST is disposed between the first lens 410 and the second lens 420.

The optical system 400 includes a plurality of lenses having a large refractive index. For example, the first lens 410, the third lens 430, the fourth lens 440, and the sixth lens 460 may have a refractive index of 1.6 or more. To further explain, the refractive indexes of the first lens 410, the third lens 430, the fourth lens 440, and the sixth lens 460 may be greater than 1.65 and less than 2.0.

The optical system 400 is configured to have a wide angle of view. For example, the half-view angle of the imaging optical system 400 is 63.26 degrees.

The optical system configured as described above exhibits aberration characteristics as shown in FIG. 8. Table 7 shows the lens characteristics of the optical system according to the present embodiment, and Table 8 shows the aspherical values of the optical system according to the present embodiment.

Table 9 shows the conditional expression values of the optical system according to the first to fourth embodiments.

Next, a portable terminal equipped with an optical system according to an embodiment of the present invention will be described with reference to FIGS. 9 to 11.

The wireless terminal 10 includes a plurality of camera modules 20, 30, and 40. For example, a first camera module 20 may be disposed on the front side of the wireless terminal 10, and a second camera module 30 and a third camera module 40 may be disposed on the rear side of the wireless terminal 10. have.

The first camera module 20 and the second camera module 30 may be configured to photograph a subject in a short distance. The half-view angle of the first camera module 20 and the second camera module 30 may be 60 degrees or more. The third camera module 40 may be configured to photograph a distant parsing body. The half-view angle of the third camera module 40 may be 30 degrees or less. Here, the first camera module 20 and the second camera module 30 may be configured with any one of the optical imaging systems 100, 200, 300, and 400 according to the first to fourth embodiments described above.

The present invention is not limited only to the embodiments described above, and those of ordinary skill in the art to which the present invention pertains, within the scope not departing from the gist of the technical idea of the present invention described in the following claims. It will be possible to implement various changes. For example, various features described in the above-described embodiments may be applied in combination with other embodiments unless a description to the contrary is explicitly stated.

100, 200, 300, 400 imaging optical system
110, 210, 310, 410 first lens
120, 220, 320, 420 second lens
130, 230, 330, 430 3rd lens
140, 240, 340, 440 4th lens
150, 250, 350, 450 5th lens
160, 260, 360, 460 6th lens
170, 270, 370, 470 (infrared cutoff) filter
180, 280, 380, 480 image sensor or top surface

Claims (17)

Which are sequentially arranged from the object side to the top surface,
A first lens having a concave image side surface;
A second lens having refractive power;
A third lens having a convex object side surface;
A fourth lens having a convex object side and a concave image side;
A fifth lens having refractive power; And
A sixth lens having refractive power and having an inflection point formed on an image side thereof;
Including,
An imaging optical system that satisfies the following conditional expression.
[Conditional Expression 1] TL/2Y ≤ 1.01
[Conditional Equation 2] 1.2 ≤ tanθ
(In the above conditional equation, TL is the distance from the object side of the first lens to the image surface, 2Y is the diagonal length of the image surface, and θ is the half-view angle of the imaging optical system) The method of claim 1,
The second lens is an optical system having a convex object side. delete The method of claim 1,
The fifth lens is an optical system having a concave object side surface. The method of claim 1,
The fifth lens is an optical system having a convex image side. The method of claim 1,
The sixth lens is an optical system having a convex object side. The method of claim 1,
The sixth lens is an optical system having a concave image side. The method of claim 1,
An imaging optical system that satisfies the following conditional expression.
[Conditional Expression] -35 <{(1/f)*(Y/tanθ)-1}*100 <-5.0
(In the above conditional formula, f is the total focal length of the imaging optical system, and Y is 1/2 of the 2Y) The method of claim 1,
An imaging optical system that satisfies the following conditional expression.
[Conditional Expression] 0.3 <(R1+R2)/(R1-R2) <2.0
(In the above conditional equation, R1 is the radius of curvature of the side of the object of the first lens, and R2 is the radius of curvature of the side of the image of the first lens) The method of claim 1,
An imaging optical system that satisfies the following conditional expression.
[Conditional Expression] 0.1 <|f/f3| <2.0
(In the above conditional formula, f is the total focal length of the imaging optical system, and f3 is the focal length of the third lens) The method of claim 1,
An imaging optical system that satisfies the following conditional expression.
[Conditional Expression] 1.8 <f/EPD <2.4
(In the above conditional equation, f is the total focal length of the imaging optical system, and EPD is the diameter of the entrance pupil) The method of claim 1,
An imaging optical system that satisfies the following conditional expression.
[Conditional Expression] 0.4 <(t1+t2)/t3 <2.0
(In the conditional expression, t1 is the thickness at the optical axis portion of the first lens, t2 is the thickness at the optical axis portion of the second lens, and t3 is the thickness at the optical axis portion of the third lens) The method of claim 1,
An imaging optical system that satisfies the following conditional expression.
[Conditional Expression] 30 <V5-V6 <40
(In the above conditional expression, V5 is the Abbe number of the fifth lens, and V6 is the Abbe number of the sixth lens) The method of claim 1,
An optical system including a diaphragm disposed between the second lens and the third lens. Which are sequentially arranged from the object side to the top surface,
A first lens having refractive power;
A second lens having refractive power;
A third lens having refractive power;
A fourth lens having a convex object side and a concave image side;
A fifth lens having a convex image side surface; And
A sixth lens having refractive power and having an inflection point formed on an image side thereof;
Including,
An imaging optical system that satisfies the following conditional expression.
[Conditional Expression 1] TL/2Y ≤ 1.01
[Conditional Expression 2] 0.3 <(R1+R2)/(R1-R2) <3.0
(In the conditional expression, TL is the distance from the object side of the first lens to the image surface, 2Y is the diagonal length of the image surface, R1 is the radius of curvature of the object side of the first lens, and R2 is the first lens. Is the radius of curvature of the upper side of the The method of claim 15,
The first lens is an optical system having a concave image side. The method of claim 15,
The second lens is an optical system having a convex object side.

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