KR102586081B1 - Imaging Lens System - Google Patents

Abstract

An imaging 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 shape on the side of the object; A fourth lens having a concave image side; 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 Lens System

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

A small camera is mounted on the wireless terminal. For example, a small camera is mounted on the front and back of the wireless terminal, respectively. These small cameras are used for a variety of purposes, such as outdoor landscape photography and indoor portrait photography, so they require performance that is comparable to that of general cameras. However, because the overall length of a high-performance small camera is long, there is a problem in that it protrudes onto the surface of the wireless terminal. Therefore, there is a need to develop an imaging optical system that can improve the performance of small cameras without increasing the overall length of the small cameras.

For reference, prior art related to the present invention includes Patent Documents 1 to 3.

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

The present invention is intended to solve the above problems, and its purpose is to provide an imaging optical system that can be mounted on a thin wireless terminal.

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; a second lens having refractive power; A third lens having a convex shape on the side of the object; A fourth lens having a concave image side; 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 imaging 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 imaging optical system according to a first embodiment of the present invention.
Figure 2 is an aberration curve of the imaging optical system shown in Figure 1
3 is a configuration diagram of an imaging optical system according to a second embodiment of the present invention.
Figure 4 is an aberration curve of the imaging optical system shown in Figure 3
5 is a configuration diagram of an imaging optical system according to a third embodiment of the present invention.
Figure 6 is an aberration curve of the imaging optical system shown in Figure 5
7 is a configuration diagram of an imaging optical system according to a fourth embodiment of the present invention.
Figure 8 is an aberration curve of the imaging optical system shown in Figure 7
Figure 9 is a front view of a wireless terminal equipped with an imaging optical system of the present invention.
Figure 10 is a rear view of the wireless terminal shown in Figure 9
Figure 11 is a cross-sectional view II of Figure 10

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

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

In addition, throughout the specification, the fact that a certain configuration is 'connected' to another configuration includes not only cases where these configurations are 'directly connected', but also cases where they are 'indirectly connected' with another configuration in between. means that In addition, 'including' a certain component means that other components may be further included rather than excluding other components, unless specifically stated to the contrary.

In this specification, the first lens refers to the lens closest to the object (or subject), and the seventh lens refers to the lens closest to the image surface (or image sensor). In this specification, the units of lens radius of curvature, thickness, TL (distance from the object side of the first lens to the image surface), Y (1/2 of the diagonal length of the image surface), and focal length are mm.

Thickness of the lens, spacing between lenses, TL is the distance from the optical axis of the lens. In addition, in the description of the shape of the lens, the shape that one side is convex means that the paraxial region of the surface is convex, and the shape that one side is concave means that the paraxial region of the 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 of the lens may be convex.

The imaging optical system includes six lenses. For example, the imaging 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 arranged 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 on one side. 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 can be made of a material with high light transmittance and excellent processability. For example, the first lens may be made of plastic material.

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

The second lens includes an aspherical surface. For example, the second lens may have an aspherical side surface of the object. The second lens can be made of a material with high light transmittance and excellent processability. For example, the second lens may be made of 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 on one side. For example, the third lens may have a convex shape on the side of the object.

The third lens includes an aspherical surface. For example, the third lens may have an aspherical image side. The third lens can be made of a material with high light transmittance and excellent processability. For example, the third lens may be made of plastic material. The third lens has a refractive index generally similar to that of the first lens. For example, if the refractive index of the first lens is less than 1.6, the refractive index of the third lens may also be less than 1.6, and if 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 on one side. 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 can be made of a material with high light transmittance and excellent processability. For example, the fourth lens may be made of plastic material. The fourth lens may generally have a high refractive index. For example, the refractive index of the fourth lens may be 1.6 or more.

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

The fifth lens includes an aspherical surface. For example, both sides of the fifth lens may be aspherical. The fifth lens can be made of a material with high light transmittance and excellent processability. For example, the fifth lens may be made of plastic material. The fifth lens has a lower refractive index than 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 with 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 aspherical surface. For example, both sides of the sixth lens may be aspherical. The sixth lens can be made of a material with high light transmittance and excellent processability. For example, the sixth lens may be made of plastic material. The sixth lens has a refractive index generally similar to that of the fourth lens. For example, the refractive index of the sixth lens may be 1.6 or more.

The aspherical surface of the first to sixth lenses can be expressed by Equation 1.

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

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

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

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

The aperture is arranged to adjust the amount of light entering the lens. For example, the aperture may be disposed between the first and second lenses or between the second and third lenses.

The imaging optical system can 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 Expression 3] 0.3 < R2/f < 2.0

[Conditional Expression 4] 0.3 < (R1+R2)/(R1-R2) < 2.0

[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 Expression 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 surface, Y is 1/2 of 2Y, θ is the half angle of view of the imaging optical system, and TL is the distance from the object side of the first lens to the image surface. is the distance, 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, and 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 of the first lens, and t2 is the thickness at the optical axis of the second lens. It 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 imaging 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 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, and a sixth lens 160. .

The first lens 110 has negative refractive power and has a shape where the object side is convex and the image side is concave. The second lens 120 has positive refractive power and has a shape where the object side is convex and the image side is concave. The third lens 130 has positive refractive power and has a shape in which the object side is convex and the image side is convex. The fourth lens 140 has negative refractive power and has a shape where the object side is convex and the image side is concave. The fifth lens 150 has positive refractive power and has a shape in which the object side is concave and the image side is convex. The sixth lens 160 has negative refractive power and has a shape where the object side is convex and the image side is concave. 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 imaging optical system 100 further includes a filter 170, an image sensor 180, and an aperture (ST). The filter 170 is disposed between the sixth lens 160 and the image sensor 180, and the aperture ST is disposed between the second lens 120 and the third lens 130.

The imaging optical system 100 includes a plurality of lenses with a high refractive index. For example, the second lens 120, fourth lens 140, and sixth lens 160 may have a refractive index of 1.6 or more. To elaborate, the refractive indices of the second lens 120, fourth lens 140, and sixth lens 160 may be greater than 1.62 and less than 2.0.

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

The imaging optical system configured as above exhibits aberration characteristics as shown in FIG. 2. Table 1 shows the lens characteristics of the imaging optical system according to this embodiment, and Table 2 shows the aspheric value of the imaging optical system according to this embodiment.

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

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, and a sixth lens 260. .

The first lens 210 has negative refractive power and has a shape where the object side is convex and the image side is concave. The second lens 220 has positive refractive power and has a shape where the object side is convex and the image side is concave. The third lens 230 has positive refractive power and has a shape in which the object side is convex and the image side is convex. The fourth lens 240 has negative refractive power and has a shape where the object side is convex and the image side is concave. The fifth lens 250 has positive refractive power and has a shape in which the object side is concave and the image side is convex. The sixth lens 260 has a negative refractive power and has a shape where the object side is convex and the image side is concave. 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 imaging optical system 200 further includes a filter 270, an image sensor 280, and an aperture (ST). The filter 270 is disposed between the sixth lens 260 and the image sensor 280, and the aperture ST is disposed between the second lens 220 and the third lens 230.

The imaging optical system 200 includes a plurality of lenses with a high refractive index. For example, the second lens 220, fourth lens 240, and sixth lens 260 may have a refractive index of 1.6 or more. To elaborate, the refractive indices of the second lens 220, fourth lens 240, and sixth lens 260 may be greater than 1.62 and less than 2.0.

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

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

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, and a sixth lens 360. .

The first lens 310 has negative refractive power and has a shape where the object side is concave and the image side is concave. The second lens 320 has positive refractive power and has a shape where the object side is convex and the image side is concave. The third lens 330 has positive refractive power and has a shape in which the object side is convex and the image side is convex. The fourth lens 340 has negative refractive power and has a shape where the side of the object is convex and the side of the image is concave. The fifth lens 350 has positive refractive power and has a shape in which the object side is concave and the image side is convex. The sixth lens 360 has negative refractive power and has a shape where the object side is convex and the image side is concave. 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 imaging optical system 300 further includes a filter 370, an image sensor 380, and an aperture (ST). The filter 370 is disposed between the sixth lens 360 and the image sensor 380, and the aperture ST is disposed between the second lens 320 and the third lens 330.

The imaging optical system 300 includes a plurality of lenses with a high refractive index. For example, the second lens 320, fourth lens 340, and sixth lens 360 may have a refractive index of 1.6 or more. To elaborate, the refractive indices of the second lens 320, fourth lens 340, and sixth lens 360 may be greater than 1.62 and less than 2.0.

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

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

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

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, and a sixth lens 460. .

The first lens 410 has negative refractive power and has a shape where the side of the object is convex and the side of the image is concave. The second lens 420 has positive refractive power and has a shape in which the object side is convex and the image side is convex. The third lens 430 has negative refractive power and has a convex side surface of the object and a concave image side surface. The fourth lens 440 has positive refractive power and has a shape where the object side is convex and the image side is concave. The fifth lens 450 has positive refractive power and has a shape in which the object side is concave and the image side is convex. The sixth lens 460 has negative refractive power and has a shape where the object side is convex and the image side is concave. 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 imaging optical system 400 further includes a filter 470, an image sensor 480, and an aperture (ST). The filter 470 is disposed between the sixth lens 460 and the image sensor 480, and the aperture ST is disposed between the first lens 410 and the second lens 420.

The imaging optical system 400 includes a plurality of lenses with a high refractive index. For example, the first lens 410, third lens 430, fourth lens 440, and sixth lens 460 may have a refractive index of 1.6 or more. To elaborate, the refractive indices of the first lens 410, third lens 430, fourth lens 440, and sixth lens 460 may be greater than 1.65 and less than 2.0.

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

The imaging optical system configured as above exhibits aberration characteristics as shown in FIG. 8. Table 7 shows the lens characteristics of the imaging optical system according to this embodiment, and Table 8 shows the aspheric value of the imaging optical system according to this embodiment.

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

Next, a mobile terminal equipped with an imaging 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 placed on the front of the wireless terminal 10, and a second camera module 30 and a third camera module 40 may be placed on the back of the wireless terminal 10. there is.

The first camera module 20 and the second camera module 30 may be configured to photograph a subject at close range. The half angle of view 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 object. The half angle of view 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 imaging optical systems 100, 200, 300, and 400 according to the first to fourth embodiments described above.

The present invention is not limited to the embodiments described above, and those of ordinary skill in the technical field to which the present invention pertains can make any changes without departing from the gist of the technical idea of the present invention as set forth in the claims below. It can be implemented with various changes. For example, various features described in the above-described embodiments may be applied in combination to other embodiments unless the contrary is explicitly stated.

100, 200, 300, 400 imaging optical system
110, 210, 310, 410 1st lens
120, 220, 320, 420 2nd lens
130, 230, 330, 430 Third lens
140, 240, 340, 440 4th lens
150, 250, 350, 450 5th lens
160, 260, 360, 460 6th lens
170, 270, 370, 470 (infrared blocking) filters
180, 280, 380, 480 image sensor or upper surface

Claims (15)

A first lens having negative refractive power and having a concave object side and a concave image side;
a second lens having a positive refractive power and a concave image side;
A third lens having a convex shape on the side of the object;
A fourth lens that has refractive power and has a convex shape on the side of the object;
A fifth lens having a convex image side; and
A sixth lens having an inflection point formed on the image side;
It consists of,
The first to sixth lenses are sequentially arranged from the object side,
An imaging optical system that satisfies the following conditional expressions.
0.3 < (R1+R2)/(R1-R2) < 2.0
(In the above conditional expression, R1 is the radius of curvature of the object side of the first lens, and R2 is the radius of curvature of the image side of the first lens) According to paragraph 1,
The second lens is an imaging optical system in which the side of the object has a convex shape. According to paragraph 1,
The sixth lens is an imaging optical system in which the side of the object has a convex shape. According to paragraph 1,
The sixth lens is an imaging optical system in which the image side has a concave shape. According to paragraph 1,
An imaging optical system that satisfies the following conditional expression.
0.5 < |f/f3| < 2.0
(In the above conditional expression, f is the total focal length of the imaging optical system, and f3 is the focal length of the third lens.) According to paragraph 1,
An imaging optical system that satisfies the following conditional expression.
0.4 < (t1+t2)/t3 < 2.0
(In the above 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.) According to paragraph 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) A first lens having a concave object side and a concave image side;
a second lens having positive refractive power and having a concave image side;
A third lens having a convex shape on the side of the object;
A fourth lens that has refractive power and has a convex side surface of the object;
A fifth lens having a convex image side; and
A sixth lens having an inflection point formed on the image side;
It consists of,
An imaging optical system in which the first to sixth lenses are sequentially arranged from the object side. According to clause 8,
The third lens is an imaging optical system in which the image side has a convex shape. delete According to clause 8,
The third lens is an imaging optical system having positive refractive power. According to clause 8,
The fourth lens is an imaging optical system having negative refractive power. According to clause 8,
An imaging optical system that satisfies the following 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) According to clause 8,
An imaging optical system that satisfies the following conditional expression.
0.3 < R2/f < 2.0
(In the above conditional equation, R2 is the radius of curvature of the image side of the first lens, and f is the focal length of the imaging optical system) According to clause 8,
An imaging optical system that satisfies the following conditional expression.
-1.5 < f/f1 < -0.05
(In the above conditional expression, is the focal length of the imaging optical system, and f1 is the focal length of the first lens)