KR20180037170A - Zoom Optical System - Google Patents

Abstract

An imaging optical system of the present invention comprises: a first lens group configured to adjust a position with respect to an image plane, and including a first lens and a second lens; a second lens group configured to adjust a position with respect to the image plane, and including a third lens to a fifth lens; and a third lens group including a sixth lens, wherein the first lens has a convex shape on a side of an object.

Description

[0001] The present invention relates to a zoom optical system,

The present invention relates to a zoom optical system capable of adjusting a focal length.

The zoom optical system can adjust the focal length. For example, the zoom optical system can adjust the focal distance so that a distant object and a near object can be clearly photographed. Such a zoom optical system is composed of a lens made of a glass material so as to easily improve the chromatic aberration.

Camera modules are becoming smaller and smaller. Accordingly, miniaturization of the zoom optical system is also required. However, it is difficult to apply to a small camera because a zoom optical system made of a glass has a high manufacturing cost and is difficult to lighten. Therefore, there is a need to develop a lightweight zoom optical system that can be mounted on a small camera module.

KR 2015-0060398 A US 2013-0314799 A1 JP 2010-224263 A

An object of the present invention is to provide a zoom optical system that can be mounted on a portable terminal.

A zooming optical system for achieving the above object is configured to adjust a position with respect to an image surface, comprising: a first lens group including a first lens and a second lens; A second lens group configured to adjust a position with respect to the image plane, and including third to fifth lenses; And a third lens group including a sixth lens, wherein the first lens has a convex shape on an object side surface.

The present invention can provide a zoom optical system capable of reducing a weight and improving aberration.

1 is a diagram showing a configuration at a middle stage of a zoom optical system according to a first embodiment of the present invention
Fig. 2 is a configuration diagram at the wide-angle end of the zoom optical system shown in Fig.
Fig. 3 is a configuration diagram at the telephoto end of the zoom optical system shown in Fig. 1
Fig. 4 is a graph showing aberration curves at the wide-angle end of the zoom optical system shown in Fig.
5 is a graph showing aberration curves at the telephoto end of the zoom optical system shown in FIG.
Fig. 6 is a table showing lens characteristics of the zoom optical system shown in Fig. 1
7 is a table showing the optical characteristics along the wide-angle end, the middle end, the telephoto end, and the distances (D1, D2, D3)
8 is a table showing aspheric characteristics of the zoom optical system shown in Fig.
9 is a diagram showing the configuration at the middle stage of the zoom optical system according to the second embodiment of the present invention
Fig. 10 is a configuration diagram at the wide-angle end of the zoom optical system shown in Fig.
11 is a diagram showing the configuration at the telephoto end of the zoom optical system shown in Fig.
12 is a graph showing aberration curves at the wide-angle end of the zoom optical system shown in Fig. 9
13 is a graph showing aberration curves at the telephoto end of the zoom optical system shown in Fig. 9
Fig. 14 is a table showing lens characteristics of the zoom optical system shown in Fig. 9
15 is a table showing the optical characteristics along the wide-angle end, the middle end, and the telephoto end, and distances (D1, D2, D3)
16 is a table showing aspheric characteristics of the zoom optical system shown in Fig. 9
17 is a configuration diagram at the middle stage of the zoom optical system according to the third embodiment of the present invention
Fig. 18 is a configuration diagram at the wide angle end of the zoom optical system shown in Fig. 17
19 is a diagram showing the configuration at the telephoto end of the zoom optical system shown in Fig.
Fig. 20 is a graph showing aberration curves at the wide-angle end of the zoom optical system shown in Fig. 17
21 is a graph showing aberration curves at the telephoto end of the zoom optical system shown in Fig. 17
22 is a table showing lens characteristics of the zoom optical system shown in Fig. 17
23 is a table showing optical characteristics along the wide-angle end, the middle end, the telephoto end, and the distances (D1, D2, D3)
24 is a table showing the aspherical surface characteristics of the zoom optical system shown in Fig. 17
25 is a configuration diagram at the middle stage of the zoom optical system according to the fourth embodiment of the present invention
Fig. 26 is a configuration diagram at the wide-angle end of the zoom optical system shown in Fig.
Fig. 27 is a diagram showing the configuration at the telephoto end of the zoom optical system shown in Fig.
28 is a graph showing aberration curves at the wide-angle end of the zoom optical system shown in Fig. 25
29 is a graph showing aberration curves at the telephoto end of the zoom optical system shown in Fig.
30 is a table showing lens characteristics of the zoom optical system shown in Fig. 25
31 is a table showing the optical characteristics along the wide-angle end, the middle end, the telephoto end, and the distances (D1, D2, D3)
32 is a table showing aspheric characteristics of the zoom optical system shown in Fig.
33 is a configuration diagram at the middle stage of the zoom optical system according to the fifth embodiment of the present invention
Fig. 34 is a configuration diagram at the wide angle end of the zoom optical system shown in Fig. 33
Fig. 35 is a configuration diagram at the telephoto end of the zoom optical system shown in Fig. 33
Fig. 36 is a graph showing aberration curves at the wide-angle end of the zoom optical system shown in Fig. 33
37 is a graph showing aberration curves at the telephoto end of the zoom optical system shown in Fig. 33
38 is a table showing lens characteristics of the zoom optical system shown in Fig. 33
39 is a table showing the optical characteristics along the wide-angle end, the middle end, the telephoto end, and the distances (D1, D2, D3)
40 is a table showing aspheric characteristics of the zoom optical system shown in Fig. 33

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In describing the present invention, it is to be understood that the terminology used herein is for the purpose of describing the present invention only and is not intended to limit the technical scope of the present invention.

In addition, throughout the specification, a configuration is referred to as being 'connected' to another configuration, including not only when the configurations are directly connected but also when they are indirectly connected with each other . Also, to "include" an element means that it may include other elements, rather than excluding other elements, unless specifically stated otherwise.

Further, in this specification, the first lens means the lens closest to the object (or the subject), and the fifth lens means the lens closest to the image surface (or image sensor). In the present specification, the curvature radius (Radius), the thickness (Thickness), the TTL, the ImgH (1/2 of the diagonal length of the upper surface) of the lens, and the unit of the focal length are all mm. In addition, the thickness of the lens, the distance between the lenses, and the TTL are the distances from the optical axis of the lens. In addition, in the explanation of the shape of the lens, the convex shape means that the optical axis portion of the surface is convex, and the concave shape of the one surface means that the optical axis portion of the surface is concave. Therefore, even if one surface of the lens is described as a convex shape, the edge portion of the lens can be concave. Similarly, even if one surface of the lens is described as a concave shape, the edge portion of the lens can be convex.

The zoom optical system is composed of a plurality of lens groups. For example, the zoom optical system may be composed of a first lens group, a second lens group, and a third lens group. The first lens group, the second lens group, and the third lens group are sequentially arranged from the object side to the image plane direction.

The first lens group includes a plurality of lenses. For example, the first lens group includes a first lens having a negative refractive power and a second lens having a positive refractive power. The first lens group composed of such lenses may have a negative refractive power as a whole. The first lens group includes a lens made of a plastic material. For example, the first lens and the second lens constituting the first lens group may all be made of a plastic material. The first lens group includes an aspherical lens. For example, both the first lens and the second lens constituting the first lens group may have an aspherical shape. The first lens group is configured to change its position with respect to the image plane. For example, the first lens group may be configured to be located closest to the image plane at the intermediate stage and farthest from the image plane at the telephoto end.

The second lens group includes a plurality of lenses. For example, the second lens group includes a third lens having a positive refractive power, a fourth lens having a negative refractive power, and a fifth lens having a positive refractive power. The second lens group composed of such lenses may have a positive refractive power as a whole. The second lens group includes a plastic lens. For example, the third lens to the fourth lens constituting the second lens group may all be made of a plastic material. The second lens group includes an aspherical lens. For example, the third lens to the fifth lens constituting the second lens group may all be aspherical. And the second lens group is configured to change its position with respect to the image plane. For example, the second lens group may be configured to be positioned closest to the image plane at the wide angle end and farthest from the image plane at the telephoto end.

The third lens group includes at least one lens. For example, the third lens group is composed of a sixth lens having a positive refractive power. The third lens group composed of such a lens can have a positive refractive power as a whole. The third lens group includes a plastic lens. For example, the sixth lens constituting the third lens group may be made of a plastic material. The third lens group includes an aspherical lens. For example, the sixth lens constituting the third lens group may have an aspherical shape. The third lens group is configured to change its position with respect to the image plane. For example, the third lens group may be configured to be located closest to the image surface at the telephoto end and farthest from the image surface at the intermediate end. However, the distance between the third lens group and the image plane is not always changed. For example, the distance between the third lens unit and the image surface may be kept constant regardless of the wide-angle end, the intermediate end, and the telephoto end.

The lens constituting each lens group may be at least one aspherical surface shape as described above. Here, the aspheric surface of the lens is expressed by the following equation (1).

In the equation (1), c is a reciprocal of a curvature radius of the lens, K is a conic constant, r is a distance from an arbitrary point on the aspherical surface to the optical axis, A to J are aspherical surface constants, From the arbitrary point on the aspheric surface to the vertex of the aspheric surface.

The zoom optical system includes a diaphragm. An aperture stop may be disposed between the first lens group and the second lens group.

The zoom optical system includes a filter. The filter blocks a part of the incident light from the first lens group through the third lens group. For example, the filter can block the infrared wavelength of the incident light. The filter can be made thin. To this end, the filter can be made of plastic.

The zoom optical system includes an image sensor. The image sensor provides a top surface through which the light refracted by the lenses can be imaged. For example, the surface of the image sensor may form an upper surface. The image sensor can be configured to implement high resolution. For example, the unit size of the pixels constituting the image sensor may be 1.12 탆 or less.

The zoom optical system can satisfy the following conditional expressions.

[Conditional expression 1] 1.9 < fG1 / fw | <3.0

[Conditional expression 2] 4.0 < ft / fw < 7.0

[Conditional expression 3] 0 < n4 < 1.7

[Conditional expression 4] 0.7 <| fG2 / fG1 | <1.2

[Conditional expression 5] 1.4 < fG2 / fw < 2.8

[Conditional expression 6] TG1 + TG2 + TG3 < 8.5

[Conditional expression 7] 0.25 <1 - MG3T ² <0.6

[Condition 8] 4.0 <MG2T / MG2W <6.8

[Conditional expression 9] 50 <V1 <60

[Conditional expression 10] 30 < V1 - V2 < 37

[Conditional expression 11] 1.5 < n3 < 1.57

[Conditional expression 12] n1 + n2 < 3.25

[Conditional expression 13] 1.6 < n4 - n1 < 0.2

[Conditional expression 14] 2.2 < fw / EPDw < 3.0

Wherein fw is the total focal length at the wide-angle end of the zooming optical system, ft is the total focal length at the telephoto end of the zooming optical system, fG1 is the combined focal length of the first lens group, N2 is the refractive index of the second lens, n3 is the refractive index of the third lens, n4 is the refractive index of the fourth lens, and TG1 is the combined refractive index of the object side surface of the first lens TG2 is the distance from the object side of the third lens to the image side of the fifth lens, TG3 is the thickness at the center of the optical axis of the sixth lens, and MG2T is the distance from the infinite distance V2 is the Abbe number of the first lens, V2 is the imaging magnification of the second lens group at the telephoto end position, MG2W is the imaging magnification of the second lens unit at the wide angle end position at infinite distance, And EPDw is the diameter of incident corrugation at the wide-angle end.

In the above conditional expressions, Conditional Expression 1 is a condition for limiting the magnitude of the refractive power of the first lens unit. For example, the first lens unit, which is outside the lower limit value of the conditional expression 1, has a strong refractive power, so it is difficult to correct the surface curvature aberration at the wide-angle end, the spherical aberration at the telephoto end, and the coma aberration. Further, the lenses of the first lens group, which deviate from the lower limit value of the conditional expression (1), are difficult to be formed. The first lens unit deviating from the upper limit value of the conditional expression (1) has a weak refractive power and it is difficult to secure the focal length, so that a clear image can not be obtained.

Conditional expression (2) in the conditional expressions is a condition for limiting the zoom optical performance. For example, a zooming optical system satisfying conditional expression 2 can obtain substantially useful optical performance.

Conditional expressions 3 and 9 to 13 in the conditional expressions are conditions for improving chromatic aberration, coma, and astigmatism. For example, a zoom optical system composed of a plastic lens satisfying the numerical ranges of conditional expressions 3 and 9 to 13 can obtain good chromatic aberration, coma aberration, and astigmatism.

Conditional expression (4) in the above conditional expressions is a condition for improving aberration and optical performance. For example, the first lens group and the first lens group satisfying Conditional Expression 4 can satisfactorily correct the astigmatism and the coma aberration. The zooming optical system satisfying the conditional expression (4) can minimize the total length of the optical system while exhibiting a zoom magnification of 5 to 6 times.

The conditional expression (5) in the conditional expressions is a condition for limiting the magnitude of the power of the second lens unit. For example, it is difficult to manufacture the second lens unit which is outside the lower limit value of the conditional expression 5, and the amount of movement for the zooming operation is large in the second lens unit which is outside the upper limit value of the conditional expression (5).

Conditional expression 6 in the conditional expressions is a condition for miniaturization of the zoom optical system. For example, the zoom optical system, which is outside the upper limit value of the conditional expression 6, has a considerable length and is therefore difficult to mount on a small terminal.

Conditional expression 7 in the conditional expressions is a condition for miniaturization of the zoom optical system and rapid AF control. For example, the zoom optical system which is out of the lower limit value of the conditional expression (7) is difficult to be miniaturized because the movement displacement of the lens group for automatic focus adjustment is large. On the other hand, the zoom optical system which is out of the upper limit value of the conditional expression (7) has a large depth of focus, which makes it difficult to control the AF.

Conditional expression 8 in the conditional expressions is a condition for realizing miniaturization and high resolution of the zoom optical system. For example, in the zoom optical system which is out of the lower limit value of the conditional expression (8), the movement displacement of the third lens unit becomes large and it is difficult to downsize. On the other hand, it is difficult for the zoom optical system to deviate from the upper limit value of the conditional expression (8), since it is difficult to correct spherical aberration through the second lens unit, and it is difficult to realize a clear resolution.

Conditional expression 14 in the conditional expressions is a condition for implementing a clear image. For example, the zoom optical system satisfying the conditional expression 14 can realize a clear image even in a low illuminance environment.

In the following, a zoom optical system according to various embodiments will be described.

First, a zoom optical system according to the first embodiment will be described with reference to FIGS. 1 to 3. FIG.

The zoom optical system 100 includes a plurality of lenses. For example, the zoom optical system 100 includes a first lens 110, a second lens 120, a third lens 130, a fourth lens 140, a fifth lens 150, a sixth lens 160 ).

The lenses constituting the zoom optical system 100 are divided into a plurality of lens groups. For example, the first lens 110 and the second lens 120 constitute the first lens group G1, and the third lens 130 to the fifth lens 150 constitute the second lens group G2. And the sixth lens 160 constitutes a third lens group G3.

The first lens group (G1) to the third lens group (G3) can move along the optical axis direction. For example, the first lens group G1 may be located closest to the image plane at the middle end and furthest from the image plane at the telephoto end. The second lens group G2 is located closest to the image plane at the wide angle end and furthest from the image plane at the telephoto end. Alternatively, the third lens group G3 may be positioned substantially at a certain distance from the image surface.

The first lens group G1 includes two lenses. For example, the first lens group G1 is composed of a first lens 110 and a second lens 120. [ The first lens 110 has a negative refractive power. The first lens 110 has a shape in which the object side is convex and the upper side is concave. The first lens 110 is made of a plastic material. The first lens 110 includes an aspherical surface. For example, both the object side and the image side of the first lens 110 may be aspherical. The second lens 120 has a positive refractive power. The second lens 120 has a convex surface on the object side and a concave surface on the image side. The second lens 120 is made of a plastic material. The second lens 120 includes an aspherical surface. For example, both the object side surface and the image side surface of the second lens 120 may be aspherical.

The second lens group G2 includes three lenses. For example, the second lens group G2 is composed of the third lens 130 to the fifth lens 130. [ The third lens 130 has a positive refractive power. The third lens 130 has a convex shape on both sides. The third lens 130 is made of a plastic material. The third lens 130 includes an aspherical surface. For example, both the object side surface and the image side surface of the third lens 130 may be aspherical. The fourth lens 140 has a negative refractive power. The fourth lens 140 has a shape in which the object side is convex and the upper side is concave. The fourth lens 140 is made of a plastic material. The fourth lens 140 includes an aspherical surface. For example, both the object side surface and the image side surface of the fourth lens 140 may be aspherical. The fifth lens 150 has a positive refractive power. The fifth lens 150 has a shape in which the object side is convex and the upper side is concave. The fifth lens 150 is made of a plastic material. The fifth lens 150 includes an aspherical surface. For example, both the object side and the image side of the fifth lens 150 may be aspherical.

The third lens group G3 includes at least one lens. For example, the third lens group G3 is composed of a sixth lens 160. [ The sixth lens 160 has a positive refractive power. The sixth lens 160 has a convex shape on both sides. The sixth lens 160 is made of a plastic material. The sixth lens 130 includes an aspherical surface. For example, both the object side and the image side of the sixth lens 160 may be aspherical.

The zoom optical system 100 includes a diaphragm ST. For example, the diaphragm ST may be disposed between the first lens group G1 and the second lens group G2. The diaphragm ST arranged in this manner adjusts the amount of light incident on the upper surface 180.

The zoom optical system 100 includes a filter 170. For example, the filter 170 may be disposed between the third lens group G3 and the upper surface 180. The filter 170 thus arranged blocks infrared rays from being incident on the upper surface 180.

The zoom optical system 100 includes an image sensor. The image sensor provides a top surface 180 where the refracted light is imaged through the lenses. In addition, the image sensor converts the optical signal formed on the top surface 180 into an electrical signal.

The zoom optical system shows the aberration characteristics shown in Figs. Fig. 4 shows aberration characteristics at the wide-angle end position, and Fig. 5 shows aberration characteristics at the telephoto end position.

6 is a table showing lens characteristics of the zoom optical system according to the first embodiment. FIG. 7 is a table showing the values of F number, D1, D2 and D3 according to the positions of the wide angle end, the middle end, and the telephoto end. 8 is a table showing the aspherical surface characteristics of the zoom optical system according to the first embodiment.

As can be seen from Fig. 7, the distance D1 between the first lens group G1 and the second lens group G2 is the longest at the wide angle end and the shortest at the telephoto end. On the other hand, the distance D2 between the second lens group G2 and the third lens group G3 is the shortest at the wide angle end and the longest at the telephoto end. However, the distance between the third lens group G3 and the upper surface 180 is substantially constant regardless of the wide angle end, the intermediate end, and the telephoto end. In this embodiment, the zoom magnification of the zoom optical system 100 is approximately 4.7.

The zoom optical system according to the second embodiment will be described with reference to Figs. 9 to 11. Fig.

The zoom optical system 200 includes a plurality of lenses. For example, the zoom optical system 200 includes a first lens 210, a second lens 220, a third lens 230, a fourth lens 240, a fifth lens 250, a sixth lens 260 ).

The lenses constituting the zoom optical system 200 are divided into a plurality of lens groups. For example, the first lens 210 and the second lens 220 constitute the first lens group G1, and the third lens 230 to the fifth lens 250 constitute the second lens group G2. And the sixth lens 260 constitutes a third lens group G3.

The first lens group (G1) to the third lens group (G3) can move along the optical axis direction. For example, the first lens group G1 may be located closest to the image plane at the middle end and furthest from the image plane at the telephoto end. The second lens group G2 is located closest to the image plane at the wide angle end and furthest from the image plane at the telephoto end. Alternatively, the third lens group G3 may be positioned substantially at a certain distance from the image surface.

The first lens group G1 includes two lenses. For example, the first lens group G1 is composed of a first lens 210 and a second lens 220. The first lens 210 has a negative refractive power. The first lens 210 has a convex surface on the object side and a concave surface on the image side. The first lens 210 is made of a plastic material. The first lens 210 includes an aspherical surface. For example, both the object side and the image side of the first lens 210 may be aspherical. The second lens 220 has a positive refractive power. The second lens 220 is convex on the object side and concave on the upper side. The second lens 220 is made of a plastic material. The second lens 220 includes an aspherical surface. For example, both the object side and the image side of the second lens 220 may be aspherical.

The second lens group G2 includes three lenses. For example, the second lens group G2 is composed of the third lens 230 to the fifth lens 230. The third lens 230 has a positive refractive power. The third lens 230 has a convex shape on both sides. The third lens 230 is made of a plastic material. The third lens 230 includes an aspherical surface. For example, both the object side and the image side of the third lens 230 may be aspherical. The fourth lens 240 has a negative refractive power. The fourth lens 240 has a convex shape on the object side and a concave shape on the upper side. The fourth lens 240 is made of a plastic material. The fourth lens 240 includes an aspherical surface. For example, both the object side surface and the image side surface of the fourth lens 240 may be aspherical. The fifth lens 250 has a positive refractive power. The fifth lens 250 has a shape in which the object side is convex and the upper side is concave. The fifth lens 250 is made of a plastic material. The fifth lens 250 includes an aspherical surface. For example, both the object side and the upper side of the fifth lens 250 may be aspherical.

The third lens group G3 includes at least one lens. For example, the third lens group G3 is composed of a sixth lens 260. [ The sixth lens 260 has a positive refractive power. The sixth lens 260 has a convex shape on both sides. The sixth lens 260 is made of a plastic material. The sixth lens 230 includes an aspherical surface. For example, both the object side and the image side of the sixth lens 260 may be aspherical.

The zoom optical system 200 includes a stop ST. For example, the diaphragm ST may be disposed between the first lens group G1 and the second lens group G2. The diaphragm ST arranged in this manner adjusts the amount of light incident on the upper surface 280.

The zoom optical system 200 includes a filter 270. For example, the filter 270 may be disposed between the third lens group G3 and the upper surface 280. The filter 270 thus arranged blocks infrared rays from being incident on the upper surface 280.

The zoom optical system 200 includes an image sensor. The image sensor provides a top surface 280 through which the refracted light is imaged through the lenses. In addition, the image sensor converts the optical signal formed on the top surface 280 into an electrical signal.

The zoom optical system shows the aberration characteristics shown in Figs. Fig. 12 shows aberration characteristics at the wide-angle end position, and Fig. 13 shows aberration characteristics at the telephoto end position.

14 is a table showing lens characteristics of the zoom optical system according to the present embodiment. 15 is a table showing the values of F number, D1, D2 and D3, which are the total focal lengths according to the positions of the wide angle end, the middle end, and the telephoto end. 16 is a table showing the aspherical surface characteristics of the zoom optical system according to the present embodiment.

15, the distance D1 between the first lens group G1 and the second lens group G2 is the longest at the wide angle end and the shortest at the telephoto end. On the other hand, the distance D2 between the second lens group G2 and the third lens group G3 is the shortest at the wide angle end and the longest at the telephoto end. However, the distance between the third lens group G3 and the upper surface 280 is substantially constant regardless of the wide angle end, the intermediate end, and the telephoto end. In this embodiment, the zoom magnification of the zoom optical system 200 is approximately 4.7.

The zoom optical system according to the third embodiment will be described with reference to Figs. 17 to 19. Fig.

The zoom optical system 300 includes a plurality of lenses. For example, the zoom optical system 300 includes a first lens 310, a second lens 320, a third lens 330, a fourth lens 340, a fifth lens 350, a sixth lens 360 ).

The lenses constituting the zoom optical system 300 are distinguished into a plurality of lens groups. For example, the first lens 310 and the second lens 320 constitute the first lens group G1, and the third lens 330 to the fifth lens 350 constitute the second lens group G2. And the sixth lens 360 constitutes a third lens group G3.

The first lens group (G1) to the third lens group (G3) can move along the optical axis direction. For example, the first lens group G1 may be located closest to the image plane at the middle end and furthest from the image plane at the telephoto end. The second lens group G2 is located closest to the image plane at the wide angle end and furthest from the image plane at the telephoto end. Alternatively, the third lens group G3 may be positioned substantially at a certain distance from the image surface.

The first lens group G1 includes two lenses. For example, the first lens group G1 is composed of a first lens 310 and a second lens 320. The first lens 310 has a negative refractive power. The first lens 310 is convex on the object side and concave on the upper side. The first lens 310 is made of a plastic material. The first lens 310 includes an aspherical surface. For example, both the object side and the image side of the first lens 310 may be aspherical. The second lens 320 has a positive refractive power. The second lens 320 is convex on the object side and concave on the upper side. The second lens 320 is made of a plastic material. The second lens 320 includes an aspherical surface. For example, both the object side and the image side of the second lens 320 may be aspherical.

The second lens group G2 includes three lenses. For example, the second lens group G2 is composed of the third lens 330 to the fifth lens 330. [ The third lens 330 has a positive refractive power. The third lens 330 has a convex shape on both sides. The third lens 330 is made of a plastic material. The third lens 330 includes an aspherical surface. For example, both the object side surface and the image side surface of the third lens 330 may be aspherical. The fourth lens 340 has a negative refractive power. The fourth lens 340 has a shape in which the object side is convex and the upper side is concave. The fourth lens 340 is made of a plastic material. The fourth lens 340 includes an aspherical surface. For example, both the object side and the image side of the fourth lens 340 may be aspherical. The fifth lens 350 has a positive refractive power. The fifth lens 350 is shaped such that the object side is convex and the upper side is concave. The fifth lens 350 is made of a plastic material. The fifth lens 350 includes an aspherical surface. For example, both the object side surface and the image side surface of the fifth lens 350 may be aspherical.

The third lens group G3 includes at least one lens. For example, the third lens group G3 is composed of a sixth lens 360. [ The sixth lens 360 has a positive refractive power. The sixth lens 360 has a convex shape on both sides. The sixth lens 360 is made of a plastic material. The sixth lens 330 includes an aspherical surface. For example, both the object side and the image side of the sixth lens 360 may be aspherical.

The zoom optical system 300 includes a stop ST. For example, the diaphragm ST may be disposed between the first lens group G1 and the second lens group G2. The diaphragm ST arranged in this way adjusts the amount of light incident on the upper surface 380. [

The zoom optical system 300 includes a filter 370. For example, the filter 370 may be disposed between the third lens group G3 and the upper surface 380. [ The filter 370 thus arranged blocks infrared rays from being incident on the upper surface 380.

The zoom optical system 300 includes an image sensor. The image sensor provides a top surface 380 through which the refracted light is imaged through the lenses. In addition, the image sensor converts the optical signal formed on the top surface 380 into an electrical signal.

The zoom optical system shows the aberration characteristics shown in Figs. 20 and 21. 20 shows aberration characteristics at the wide-angle end position, and Fig. 21 shows aberration characteristics at the telephoto end position.

22 is a table showing lens characteristics of the zoom optical system according to the present embodiment. 23 is a table showing the values of F number, D1, D2, and D3 of the entire focal length according to the positions of the wide angle end, the middle end, and the telephoto end. 24 is a table showing the aspherical surface characteristics of the zoom optical system according to the present embodiment.

23, the distance D1 between the first lens group G1 and the second lens group G2 is the longest at the wide angle end and the shortest at the telephoto end. On the other hand, the distance D2 between the second lens group G2 and the third lens group G3 is the shortest at the wide angle end and the longest at the telephoto end. However, the distance between the third lens group G3 and the upper surface 380 is substantially constant regardless of the wide angle end, the intermediate end, and the telephoto end. In this embodiment, the zoom magnification of the zoom optical system 300 is approximately 4.7.

A zoom optical system according to the fourth embodiment will be described with reference to Figs. 25 to 27. Fig.

The zoom optical system 400 includes a plurality of lenses. For example, the zoom optical system 400 includes a first lens 410, a second lens 420, a third lens 430, a fourth lens 440, a fifth lens 450, a sixth lens 460 ).

The lenses constituting the zoom optical system 400 are divided into a plurality of lens groups. For example, the first lens 410 and the second lens 420 constitute the first lens group G1, and the third lens 430 to the fifth lens 450 constitute the second lens group G2. And the sixth lens 460 constitutes the third lens group G3.

The first lens group (G1) to the third lens group (G3) can move along the optical axis direction. For example, the first lens group G1 may be located closest to the image plane at the middle end and furthest from the image plane at the telephoto end. The second lens group G2 is located closest to the image plane at the wide angle end and furthest from the image plane at the telephoto end. Alternatively, the third lens group G3 may be positioned substantially at a certain distance from the image surface.

The first lens group G1 includes two lenses. For example, the first lens group G1 is composed of a first lens 410 and a second lens 420. The first lens 410 has a negative refractive power. The first lens 410 has a convex surface on the object side and a concave surface on the image side. The first lens 410 is made of a plastic material. The first lens 410 includes an aspherical surface. For example, both the object side and the image side of the first lens 410 may be aspherical. The second lens 420 has a positive refractive power. The second lens 420 has a shape in which the object side is convex and the upper side is concave. The second lens 420 is made of a plastic material. The second lens 420 includes an aspherical surface. For example, both the object side and the image side of the second lens 420 may be aspherical.

The second lens group G2 includes three lenses. For example, the second lens group G2 is composed of a third lens 430 to a fifth lens 430. [ The third lens 430 has a positive refractive power. The third lens 430 has a convex shape on both sides. The third lens 430 is made of a plastic material. The third lens 430 includes an aspherical surface. For example, both the object side surface and the image side surface of the third lens 430 may be aspherical. The fourth lens 440 has a negative refractive power. The fourth lens 440 has a convex surface on the object side and a concave surface on the image side. The fourth lens 440 is made of a plastic material. The fourth lens 440 includes an aspherical surface. For example, both the object side and the image side of the fourth lens 440 may be aspherical. The fifth lens 450 has a positive refractive power. The fifth lens 450 is shaped such that the object side is convex and the upper side is concave. The fifth lens 450 is made of a plastic material. The fifth lens 450 includes an aspherical surface. For example, both the object side surface and the image side surface of the fifth lens 450 may be aspherical.

The third lens group G3 includes at least one lens. For example, the third lens group G3 is composed of a sixth lens 460. [ The sixth lens 460 has a positive refractive power. The sixth lens 460 has a convex shape on both sides. The sixth lens 460 is made of a plastic material. The sixth lens 430 includes an aspherical surface. For example, both the object side and the image side of the sixth lens 460 may be aspherical.

The zoom optical system 400 includes a stop ST. For example, the diaphragm ST may be disposed between the first lens group G1 and the second lens group G2. The diaphragm ST arranged in this way adjusts the amount of light incident on the upper surface 480. [

The zoom optical system 400 includes a filter 470. For example, the filter 470 may be disposed between the third lens group G3 and the upper surface 480. [ The filter 470 thus arranged blocks infrared rays from being incident on the upper surface 480.

The zoom optical system 400 includes an image sensor. The image sensor provides a top surface 480 where the refracted light is imaged through the lenses. In addition, the image sensor converts the optical signal formed on the top surface 480 into an electrical signal.

The zoom optical system shows the aberration characteristics shown in Figs. 28 and 29. Fig. 28 shows aberration characteristics at the wide-angle end position, and Fig. 29 shows aberration characteristics at the telephoto end position.

30 is a table showing lens characteristics of the zoom optical system according to the present embodiment. 31 is a table showing the values of F number, D1, D2 and D3, the total focal length according to the position of the wide angle end, the middle end, and the telephoto end. 32 is a table showing the aspherical surface characteristics of the zoom optical system according to the present embodiment.

31, the distance D1 between the first lens group G1 and the second lens group G2 is the longest at the wide angle end and the shortest at the telephoto end. On the other hand, the distance D2 between the second lens group G2 and the third lens group G3 is the shortest at the wide angle end and the longest at the telephoto end. However, the distance between the third lens group G3 and the upper surface 480 is substantially constant regardless of the wide angle end, the intermediate end, and the telephoto end. In this embodiment, the zoom magnification of the zoom optical system 400 is approximately 4.7.

33 to 35, a zoom optical system according to the fifth embodiment will be described.

The zoom optical system 500 includes a plurality of lenses. For example, the zoom optical system 500 includes a first lens 510, a second lens 520, a third lens 530, a fourth lens 540, a fifth lens 550, a sixth lens 560 ).

The lenses constituting the zoom optical system 500 are distinguished into a plurality of lens groups. For example, the first lens 510 and the second lens 520 constitute the first lens group G1, and the third lens 530 to the fifth lens 550 constitute the second lens group G2. And the sixth lens 560 constitutes the third lens group G3.

The first lens group (G1) to the third lens group (G3) can move along the optical axis direction. For example, the first lens group G1 may be located closest to the image plane at the middle end and furthest from the image plane at the telephoto end. The second lens group G2 is located closest to the image plane at the wide angle end and furthest from the image plane at the telephoto end. Alternatively, the third lens group G3 may be positioned substantially at a certain distance from the image surface.

The first lens group G1 includes two lenses. For example, the first lens group G1 is composed of a first lens 510 and a second lens 520. [ The first lens 510 has a negative refractive power. The first lens 510 has a concave shape on an object side and a concave on an upper side. The first lens 510 is made of a plastic material. The first lens 510 includes an aspherical surface. For example, both the object side and the image side of the first lens 510 may be aspherical. The second lens 520 has a positive refractive power. The second lens 520 is convex on the object side and concave on the upper side. The second lens 520 is made of a plastic material. The second lens 520 includes an aspherical surface. For example, both the object side and the image side of the second lens 520 may be aspherical.

The second lens group G2 includes three lenses. For example, the second lens group G2 is composed of the third lens 530 to the fifth lens 530. [ The third lens 530 has a positive refractive power. The third lens 530 has a convex shape on both sides. The third lens 530 is made of a plastic material. The third lens 530 includes an aspherical surface. For example, both the object side and the image side of the third lens 530 may be aspherical. The fourth lens 540 has a negative refractive power. The fourth lens 540 is shaped such that the object side is convex and the upper side is concave. The fourth lens 540 is made of a plastic material. The fourth lens 540 includes an aspherical surface. For example, both the object side and the image side of the fourth lens 540 may be aspherical. The fifth lens 550 has a positive refractive power. The fifth lens 550 is convex on the object side and concave on the upper side. The fifth lens 550 is made of a plastic material. The fifth lens 550 includes an aspherical surface. For example, both the object side and the image side of the fifth lens 550 may be aspherical.

The third lens group G3 includes at least one lens. For example, the third lens group G3 is composed of a sixth lens 560. [ The sixth lens 560 has a positive refractive power. The sixth lens 560 has a convex shape on both sides. The sixth lens 560 is made of a plastic material. The sixth lens 530 includes an aspherical surface. For example, both the object side and the image side of the sixth lens 560 may be aspherical.

The zoom optical system 500 includes a stop ST. For example, the diaphragm ST may be disposed between the first lens group G1 and the second lens group G2. The diaphragm ST arranged in this manner adjusts the amount of light incident on the upper surface 580.

The zoom optical system 500 includes a filter 570. For example, the filter 570 may be disposed between the third lens group G3 and the upper surface 580. [ The filter 570 thus arranged blocks infrared rays from being incident on the upper surface 580.

The zoom optical system 500 includes an image sensor. The image sensor provides a top surface 580 over which the refracted light is imaged through the lenses. In addition, the image sensor converts the optical signal formed on the top surface 580 into an electrical signal.

The zoom optical system shows the aberration characteristics shown in Figs. 36 and 37. Fig. 36 shows aberration characteristics at the wide-angle end position, and Fig. 37 shows aberration characteristics at the telephoto end position.

38 is a table showing lens characteristics of the zoom optical system according to the present embodiment. 39 is a table showing the values of the total focal length F number, D1, D2, and D3 according to the positions of the wide angle end, the middle end, and the telephoto end. 40 is a table showing the aspherical surface characteristics of the zoom optical system according to the present embodiment.

39, the distance D1 between the first lens group G1 and the second lens group G2 is the longest at the wide angle end and the shortest at the telephoto end. On the other hand, the distance D2 between the second lens group G2 and the third lens group G3 is the shortest at the wide angle end and the longest at the telephoto end. However, the distance between the third lens group G3 and the upper surface 580 is substantially constant regardless of the wide angle end, the intermediate end, and the telephoto end. In this embodiment, the zoom magnification of the zoom optical system 500 is approximately 6. [

Table 1 shows optical property values of the lens group of the zoom optical system according to the first to fifth embodiments.

Table 2 is a calculation value of the zoom optical system according to the first to fifth embodiments with respect to the condition equation.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the inventions And various modifications may be made.

100, 200, 300, 400, 500 imaging optical system
110, 210, 310, 410, 510 A first lens
120, 220, 320, 420, 520,
130, 230, 330, 430, 530 Third lens
140, 240, 340, 440, 540 The fourth lens
150, 250, 350, 450, 550 The fifth lens
160, 260, 360, 460, 560 The sixth lens
170, 270, 370, 470, 570 filters
180, 280, 380, 480, 580 (of the image sensor)
ST iris

Claims (16)

In order from the object side,
A first lens group having negative refractive power;
A second lens group having a positive refractive power; And
A third lens group having positive refractive power;
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The distance between the first lens group and the second lens group during zooming from the wide-angle end to the telephoto end is reduced,
The distance between the second lens group and the third lens group is changed,
The first lens group includes,
A first lens made of a plastic material having negative refractive power and having one aspherical surface; And
A second lens made of a plastic material having a positive refracting power and having a meniscus shape;
&Lt; / RTI &gt;
The second lens group includes,
A third lens having a positive refracting power and having a convex shape on an object side;
A fourth lens made of a plastic material; And
A fifth lens made of a plastic material;
&Lt; / RTI &gt;
The third lens group is composed of a sixth lens made of a plastic material having a positive refractive power,
A zoom optical system satisfying the following conditional expressions.
[Conditional expression] 1.9 ≤ | fG1 / fw | ≤ 3.0
[Conditional expression] 4.0 <ft / fw <7.0
[Conditional expression] 1.61 <n4 <1.68
(Where fw is the total focal length at the wide-angle end of the zooming optical system, fG1 is the combined focal length of the first lens group, ft is the total focal length at the telephoto end of the zooming optical system, Refractive index of the fourth lens) The method according to claim 1,
And a diaphragm disposed between the first lens group and the second lens group. The method according to claim 1,
Wherein the first lens to the sixth lens are made of a plastic material. The method according to claim 1,
Wherein the first lens to the sixth lens are aspherical surfaces. The method according to claim 1,
A zoom optical system satisfying the following conditional expression.
[Conditional expression] 1.51 <n3 <1.57
(N3 is the refractive index of the third lens in the conditional expression) The method according to claim 1,
A zoom optical system satisfying the following conditional expression.
[Conditional expression] 0.7 <| fG2 / fG1 | <1.2
(FG1 in the above conditional formula is a combined focal length of the first lens group, and fG2 is a combined focal length of the second lens group) The method according to claim 1,
A zoom optical system satisfying the following conditional expression.
[Conditional expression] 1.4 <fG2 / fw <2.8
(FG2 in the above conditional formula is the combined focal length of the second lens group, and fw is the total focal length at the wide-angle end of the zooming optical system) The method according to claim 1,
A zoom optical system satisfying the following conditional expression.
[Conditional expression] TG1 + TG2 + TG3 < 8.5
(Where TG1 is the distance from the object side of the first lens to the image side of the second lens, TG2 is the distance from the object side of the third lens to the image side of the fifth lens, The thickness at the center of the optical axis of the sixth lens) The method according to claim 1,
A zoom optical system satisfying the following conditional expression.
[Conditional expression] 0.25 <1 - MG3T ² <0.6
(MG3T in the above-described conditional expression is the imaging magnification of the third lens group at the telephoto end position at the infinite distance) The method according to claim 1,
A zoom optical system satisfying the following conditional expression.
[Conditional expression] 4.0 <MG2T / MG2W <6.8
(MG2T in the above conditional expression is an image forming magnification of the second lens unit at the telephoto end position at an infinite distance, and MG2W is an imaging magnification of the second lens unit at the wide angle end position at the infinite distance) The method according to claim 1,
A zoom optical system satisfying the following conditional expression.
[Conditional expression] 50 <V1 <60
(V1 is the Abbe number of the first lens in the above conditional expression) The method according to claim 1,
A zoom optical system satisfying the following conditional expression.
[Conditional expression] 30 <V1 - V2 <37
(Where V1 is the Abbe number of the first lens and V2 is the Abbe number of the second lens in the above conditional expression) The method according to claim 1,
A zoom optical system satisfying the following conditional expression.
[Conditional expression] n1 + n2 < 3.25
(Where n1 is the refractive index of the first lens and n2 is the refractive index of the second lens in the conditional expression) The method according to claim 1,
A zoom optical system satisfying the following conditional expression.
[Conditional expression] 0 <n4 - n1 <0.2
(Where n1 is the refractive index of the first lens and n4 is the refractive index of the fourth lens in the conditional expression) The method according to claim 1,
A zoom optical system satisfying the following conditional expression.
[Conditional expression] 2.2 <fw / EPDw <3.0
(Where fw is the total focal length at the wide-angle end of the zoom optical system and EPDw is the incident pupil diameter at the wide-angle end) A plurality of light emitting elements arranged sequentially from the object side to the image surface,
A first lens having a negative refractive power;
A second lens having a positive refractive power;
A third lens having a positive refractive power;
A fourth lens having a negative refractive power;
A fifth lens having a positive refractive power; And
A sixth lens having a positive refracting power and having an upward convex shape;
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Wherein the first lens and the fifth lens are configured to change positions with respect to the image surface.

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