KR20200037938A - Optical Lens - Google Patents

Abstract

A problem to be solved by the present invention is to provide an imaging lens capable of realizing a long focal length even with a short TTL. The imaging lens according to one aspect of the present invention comprises, in order from an object side, a first lens including a first reflective surface formed on the object side surface, and a second lens including a second reflective surface formed on the image side surface. The first reflective surface is disposed on an optical axis, and the second reflective surface is spaced apart from the optical axis.

Description

Imaging lens {Optical Lens}

The present invention relates to an imaging lens, and more particularly to an imaging lens suitable for a camera module using a high resolution image sensor.

Recently, a camera module for a communication terminal, a digital still camera (DSC), a cam coater, and a PC camera (an imaging device attached to a personal computer) have been studied in connection with the image pickup system. have. The most important component for the camera module associated with such an image pickup system to obtain an image is an imaging lens that determines the image.

Meanwhile, an attempt has been made to construct a high-resolution imaging lens using a plurality of lenses, but there is a problem that it is difficult to implement a long focal length in a short through-the-lens (TTL).

The problem to be solved by the present invention is to provide an imaging lens capable of realizing a long focal length even with a short TTL.

An imaging lens according to an aspect of the present invention for achieving the above object includes a first lens including a first reflective surface formed on a water side in order from an object side; And a second lens including a second reflective surface formed on the image side surface, wherein the first reflective surface is disposed on the optical axis, and the second reflective surface is disposed away from the optical axis.

In addition, the first reflective surface may be disposed in a central region of the water side of the first lens, and the second reflective surface may be disposed in an outer region of the upper side of the second lens.

In addition, light incident from the object side passes through the first lens, light passing through the first lens is reflected from the second reflective surface of the second lens, and light reflected from the second reflective surface is Light reflected from the first reflective surface and reflected from the first reflective surface may pass through the second lens.

Also, the first reflective surface and the second reflective surface may be non-overlapping in the optical axis direction.

Also, the second reflective surface may overlap the first lens in an optical axis direction.

Also, the second reflective surface may include two second reflective surfaces.

In addition, the first lens may have a concave water side and an convex image surface.

In addition, the second lens may be formed with a concave water side, and an image convex surface.

In addition, a third lens disposed next to the second lens from the object side may be included, and the water side surface of the third lens may include an inflection point.

Also, the second reflective surface may be non-overlapping with the third lens in the optical axis direction.

In addition, a fourth lens disposed next to the third lens from the object side may be formed, and the water side of the fourth lens may be concave and the image side may be convex.

Also, the second reflective surface may be non-overlapping in the optical axis direction with the fourth lens.

In addition, a fifth lens disposed next to the fourth lens from the object side may be formed, and the water side of the fifth lens may be concave and the image side may be convex.

Also, the second reflective surface may be non-overlapping in the optical axis direction with the fifth lens.

In addition, a sixth lens disposed next to the fifth lens from the object side may be formed, and the water side surface of the sixth lens may be concave and the image side surface may be convex.

Also, the second reflective surface may overlap the sixth lens in the optical axis direction.

Further, a filter disposed next to the sixth lens from the object side may be included.

In addition, the filter may be any one of an infrared filter and a cover glass.

Through this embodiment, an imaging lens capable of realizing a long focal length even with a short TTL can be provided.

1 is a configuration diagram of an imaging lens according to an embodiment of the present invention.
2 is a view showing an optical path through an imaging lens according to an embodiment of the present invention.
3 to 5 are views showing aberration characteristics of an imaging lens according to an embodiment of the present invention.
6 is a configuration diagram of an imaging lens according to another embodiment of the present invention.
7 is a view showing an optical path through an imaging lens according to another embodiment of the present invention.
8 to 10 are views showing aberration characteristics of an imaging lens according to another embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

However, the technical spirit of the present invention is not limited to some embodiments described, but may be implemented in various different forms, and within the scope of the technical spirit of the present invention, one or more of its components between embodiments may be selectively selected. It can be used in combination or substitution.

In addition, terms (including technical and scientific terms) used in the embodiments of the present invention, unless clearly defined and specifically described, can be generally understood by those skilled in the art to which the present invention pertains. It can be interpreted as a meaning, and terms that are commonly used, such as predefined terms, may be interpreted by considering the contextual meaning of the related technology.

In addition, the terms used in the embodiments of the present invention are for describing the embodiments and are not intended to limit the present invention.

In the present specification, a singular form may also include a plural form unless specifically stated in the phrase, and is combined with A, B, C when described as "at least one (or more than one) of A and B, C". It can contain one or more of all possible combinations.

In addition, in describing the components of the embodiments of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are only for distinguishing the component from other components, and the term is not limited to the nature, order, or order of the component.

And, when a component is described as being 'connected', 'coupled', or 'connected' to another component, the component is directly 'connected', 'coupled', or 'connected' to the other component In addition to the case, it may also include a case of 'connected', 'coupled', or 'connected' due to another component between the component and the other components.

Further, when described as being formed or disposed in the "top (top)" or "bottom (bottom)" of each component, "top (top)" or "bottom (bottom)" means that the two components are directly in contact with each other. This includes not only the case of contact, but also the case where one or more other components are formed or disposed between two components. In addition, when expressed as "up (up)" or "down (down)", the meaning of the downward direction as well as the upward direction based on one component may be included.

The 'optical axis' used below is defined as the optical axis of the imaging lens disposed in the camera module.

Hereinafter, the present invention will be described in more detail according to the accompanying drawings.

1 is a configuration diagram of an imaging lens according to an embodiment of the present invention. 2 is a view showing an optical path through an imaging lens according to an embodiment of the present invention. 3 to 5 are views showing aberration characteristics of an imaging lens according to an embodiment of the present invention. 6 is a configuration diagram of an imaging lens according to another embodiment of the present invention. 7 is a view showing an optical path through an imaging lens according to another embodiment of the present invention. 8 to 10 are views showing aberration characteristics of an imaging lens according to another embodiment of the present invention. The thickness, size, and shape of the lenses in FIGS. 1, 2, 6, and 7 are exaggerated for explanation, and spherical or aspherical shapes are presented as an example and are not limited thereto.

1 and 2, the imaging lens 10 according to an embodiment of the present invention includes a first lens 100, a second lens 200, and a third lens ( 300), a fourth lens 400, a fifth lens 500, a sixth lens 600, a filter 700, and a light receiving element may be included, but other additional configurations are not excluded.

The light corresponding to the image information of the subject includes a first lens 100, a second lens 200, a third lens 300, a fourth lens 400, a fifth lens 500, and 6 passes through the lens 600 and the filter 700 and is incident on the light receiving element.

Hereinafter, in describing the configuration of each lens, the term "water side" means the surface of the lens facing the object side with respect to the optical axis, and the term "image side" refers to the imaging surface with respect to the optical axis. It means the surface of the lens.

The first lens 100 may include a first reflective surface 130 formed on the water side 110. The water side surface 110 of the first lens 100 may be concave. The image side surface 110 of the first lens 100 may be formed convexly. Light incident from the object side may pass through the first lens 100.

The first reflective surface 130 may be disposed on the optical axis C. The first reflective surface 130 may be disposed in a central region of the water side surface 110 of the first lens 100. The first reflective surface 130 may not overlap with the second reflective surface 230 in the optical axis C direction. The first reflective surface 130 may reflect light reflected from the second reflective surface 230 toward the second lens 200. At this time, the light reflected from the first reflective surface 130 may pass through a separation area in which the central region of the second lens 200, specifically, the two second reflective surfaces 230 are separated.

The second lens 200 may include a second reflective surface 230 formed on the image side 220. The water side 210 of the second lens 200 may be concave. The second lens 200 may have a convex image side 220.

The second reflective surface 230 may be disposed spaced apart from the optical axis C. The second reflective surface 230 may be disposed in an outer area of the image side surface 220 of the second lens 200. The second reflective surface 230 may not overlap the first reflective surface 130 in the optical axis C direction. The second reflective surface 230 may overlap a portion of the first lens 100 in the optical axis C direction. The second reflective surface 230 may reflect light passing from the object side through the first lens 100 toward the first reflective surface 130 of the first lens 100. The second reflective surface 230 may include two second reflective surfaces 230. One of the two second reflective surfaces 230 may be disposed above the optical axis C, and the other may be disposed below the optical axis C. Light reflected from the first reflective surface 130 may pass through the second lens 200 through a space between the two second reflective surfaces 230.

The water side 310 of the third lens 300 may include an inflection point. The water side 310 of the third lens 300 may include one inflection point. The image side surface 320 of the third lens 300 may include an inflection point. The image side surface 320 of the third lens 300 may include one inflection point. The third lens 300 may not overlap with the second reflective surface 230 in the optical axis C direction. The third lens 300 is a part of the first lens 100, the second lens 200, the fourth lens 400, the fifth lens 500 and the sixth lens 600 and the optical axis (C) direction Can overlap. The third lens 300 may be formed in an aspherical shape.

The water side 410 of the fourth lens 400 may be concave. The image side surface 420 of the fourth lens 400 may be formed convexly. The fourth lens 400 may not overlap with the second reflective surface 230 in the optical axis C direction. The fourth lens 400 may overlap a portion of the first lens 100, the second lens 200, and the sixth lens 600 in the optical axis C direction. The fourth lens 400 may be formed in an aspherical shape.

The water side 510 of the fifth lens 500 may be concave. The image side surface 520 of the fifth lens 500 may be formed convexly. The fifth lens 500 may not overlap the second reflective surface 230 in the optical axis C direction. The fifth lens 500 may be formed in an aspherical shape.

The water side 610 of the sixth lens 600 may be formed concavely. The image side 620 of the sixth lens 600 may be formed convexly. The sixth lens 600 may overlap the second reflective surface 230 in the optical axis C direction. The sixth lens 600 may be formed in an aspherical shape.

The filter 700 may be at least one of an infrared filter and a cover glass. When an infrared filter is applied as the filter 700, radiation heat emitted from external light may be blocked from being transmitted to the light receiving element. In addition, the infrared filter transmits visible light and reflects infrared light to flow out.

The light receiving element may include an image sensor such as a Charge Coupled Device (CCD) or a Complementary Metal Oxide Semiconductor (CMOS).

Hereinafter, the operational effects of the present invention will be described with reference to specific examples. The aspherical surface mentioned below is obtained from the well-known equation (1).

Here, z: distance from the vertex of the lens to the optical axis

c: Basic curvature of the lens

Y: Distance in the direction perpendicular to the optical axis

K: Conic constant

A, B, C, D, E, F: Aspheric coefficient

[Example 1]

Table 1 below shows the aspheric coefficient values of each lens.

Radius of curvature K A B C D E One -6.51497 1.082243 2 -5.572979 -2.88234 3 -8.43306 -6.54074 4 -9.21163 0.068731 5 -2.20965 0 0.146801 -0.03791 0.02037 -0.00331 6 -4.62961 0 0.109584 -0.03 0.015278 0.000923 7 -6.25553 0 -0.010584 0.092356 -0.13507 0.042968 0 8 -6.24811 0 -0.21048 0.26101 -0.18994 0.044692 0 9 -45.005 0 -0.31305 0.176785 0.033126 -0.068 0.015882 10 -5.288596 0 0.124455 -0.16753 0.094327 -0.03399 0.004888 11 -2.45627 0 0.095471 -0.00276 -0.03125 0.011872 -0.00122 12 394.064 0 -0.3219 0.244162 0.08414 0.01321 -0.00077

Tables 2 and 3 below show the characteristics of each lens.

First lens Second lens Third lens 4th lens 5th lens 6th lens Refractive index 1.54829 1.53528 1.54676 1.59846 1.54724 1.54724 Abbe 47.0103 55.6991 55.8991 28.3419 55.8883 55.8883 Focal length 5.05873 -0.387004 -0.556351 53.3324 0.761833 -0.311118 Lens thickness 0.0737161 0.0852054 0.0353659 0.0353659 0.0443957 0.0599284

In Table 3, D12 is a distance between the first lens 100 and the second lens 200, D23 is a distance between the second lens 200 and the third lens 300, and D34 is a third lens ( 300) is the distance between the fourth lens 400, D45 is the distance between the fourth lens 400 and the fifth lens 500, D56 is between the fifth lens 500 and the sixth lens 600 It is the distance of, and it means the total lens length (TL).

D12 / TL 0.288618 D23 / TL 0.0365854 D34 / TL 0.147513 D45 / TL 0.0412737 D56 / TL 0.0162602

In Table 4, F is the focal length, FNO is the aperture size, theta half FOV, IH is the image height, TL is the total length of the optical system, FLL is between the first lens 100 and the second lens 200 The distance, BLL, means the distance between the third lens 300 and the sixth lens 600.

F 14.333 FNO 2.3 theta 8.68909 tan theta -0.905217 TL / F 0.411094 TL / IH 2.63634 FLL / TL 0.44754 BLL / TL 0.380103

FIG. 3 is a graph measuring longitudinal spherical aberration according to the first embodiment, FIG. 4 is a graph measuring astigmatic field curves according to the first embodiment, and FIG. 5 is a first implementation This is a graph of distortion distortion according to an example.

3 to 5, the Y-axis refers to the size of the image, and the X-axis refers to the focal length (in mm) and distortion (in%). 3 to 5, it is interpreted that the closer the curves are to the Y axis, the better the aberration correction function. In the illustrated aberration diagram, since the values of the images appear in the vicinity of the Y axis in almost all fields, it can be seen that spherical aberration, astigmatism and distortion aberration all show excellent values.

[Example 2]

Table 5 below shows the aspheric coefficient values of each lens.

Radius of curvature K A B C D E One -6.51497 1.079356 2 -5.73788 -2.87512 3 -8.43556 -6.51048 4 -9.21737 0.06798 5 -2.23686 0 0.144906 -0.03725 0.020969 -0.00363 6 -4.9515 0 0.107337 -0.02796 0.014668 0.001448 7 -5.46458 0 0.09201 0.074235 -0.13432 0.045252 0 8 -5.12712 0 -0.20903 0.26952 -0.20055 0.047572 0 9 -33.1394 0 -0.32493 0.205869 0.014448 -0.06496 0.016115 10 -5.45057 0 0.131704 -0.18659 0.10647 -0.03754 0.005312 11 -2.54521 0 0.100966 -0.01267 -0.02505 0.010227 -0.00107 12 54.2184 0 -0.33167 0.259373 -0.09204 0.014928 -0.00091

The following Table 6 and Table 7 show the characteristics of each lens.

First lens Second lens Third lens 4th lens 5th lens 6th lens Refractive index 1.54792 1.53528 1.54676 1.59393 1.54757 1.53748 Abbe 47.2657 55.6991 55.8991 29.1613 55.1327 56.0991 Focal length 5.09374 -0.385378 -0.532805 7.89381 0.824786 -0.3113497 Lens thickness 0.0734811 0.0869561 0.0353565 0.0353565 0.0446435 0.0606557

D12 in Table 7 below is a distance between the first lens 100 and the second lens 200, D23 is a distance between the second lens 200 and the third lens 300, and D34 is a third lens ( 300) is the distance between the fourth lens 400, D45 is the distance between the fourth lens 400 and the fifth lens 500, D56 is between the fifth lens 500 and the sixth lens 600 It is the distance of, and it means the total lens length (TL).

D12 / TL 0.288541 D23 / TL 0.0365757 D34 / TL 0.152504 D45 / TL 0.0336724 D56 / TL 0.0162558

In Table 8, F is the focal length, FNO is the aperture size, theta half FOV, IH is the image height, TL is the total length of the optical system, FLL is between the first lens 100 and the second lens 200 The distance, BLL, means the distance between the third lens 300 and the sixth lens 600.

F 14.3962 FNO 2.3 theta 8.65178 tan theta -0.975495 TL / F 0.409399 TL / IH 2.63704 FLL / TL 0.448978 BLL / TL 0.378444

FIG. 8 is a graph measuring longitudinal spherical aberration according to the first embodiment, FIG. 9 is a graph measuring astigmatic field curves according to the first embodiment, and FIG. 10 is a first implementation This is a graph of distortion distortion according to an example.

8 to 10, the Y-axis means the size of the image, and the X-axis means the focal length (in mm) and distortion (in%). 8 to 10, it is interpreted that the closer the curves are to the Y axis, the better the aberration correction function. In the illustrated aberration diagram, since the values of the images appear in the vicinity of the Y axis in almost all fields, it can be seen that spherical aberration, astigmatism and distortion aberration all show excellent values.

Although the embodiments of the present invention have been described with reference to the accompanying drawings, those skilled in the art to which the present invention pertains may implement the present invention in other specific forms without changing its technical spirit or essential features. You will understand. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive.

10: imaging lens 100: first lens
130: first reflective surface 200: second lens
230: second reflective surface 300: third lens
400: fourth lens 500: fifth lens
600: sixth lens 700: filter

Claims (18)

In order from the object side,
A first lens including a first reflective surface formed on a water side; And
It includes a second lens including a second reflective surface formed on the image side,
The first reflective surface is disposed on the optical axis,
The second reflective surface is an imaging lens that is disposed spaced apart from the optical axis. According to claim 1,
The first reflective surface is disposed in a central region of the water side of the first lens,
The second reflective surface is an imaging lens disposed in an outer area of the image-side surface of the second lens. According to claim 2,
The light incident from the object side passes through the first lens,
Light passing through the first lens is reflected from the second reflective surface of the second lens,
Light reflected from the second reflective surface is reflected from the first reflective surface,
The light reflected from the first reflective surface passes through the second lens. According to claim 1,
An imaging lens in which the first reflective surface and the second reflective surface are non-overlapping in the optical axis direction. According to claim 1,
The second reflective surface is an imaging lens overlapping the first lens in the optical axis direction. According to claim 1,
The second reflective surface is an imaging lens comprising two second reflective surfaces. According to claim 1,
The first lens is an imaging lens in which the water side is concave and the image side is convex. According to claim 1,
The second lens is an imaging lens in which the water side is concave and the image side is convex. According to claim 1,
And a third lens disposed next to the second lens from the object side,
An imaging lens including an inflection point on the water side of the third lens. The method of claim 9,
The second reflective surface is an imaging lens that is non-overlapping in the optical axis direction with the third lens. The method of claim 9,
And a fourth lens disposed next to the third lens from the object side,
An imaging lens in which the water side of the fourth lens is concave and the image side is convex. The method of claim 11,
The second reflective surface is an imaging lens that is non-overlapping in the optical axis direction with the fourth lens. The method of claim 11,
And a fifth lens disposed next to the fourth lens from the object side,
An imaging lens in which the water side of the fifth lens is concave and the image side is convex. The method of claim 13,
The second reflective surface is an imaging lens that is non-overlapping in the optical axis direction with the fifth lens. The method of claim 13,
A sixth lens disposed next to the fifth lens from the object side,
An imaging lens in which the water side of the sixth lens is concave and the image side is convex. The method of claim 15,
The second reflective surface is an imaging lens overlapping the sixth lens in the optical axis direction. The method of claim 15,
An imaging lens comprising a filter disposed next to the sixth lens from the object side. The method of claim 17,
The filter is any one of an infrared filter and a cover glass.

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