Optical system, optical module including same, and camera module

Abstract

An optical system according to an embodiment includes a first lens group, a second lens group, and a third lens group, each of which includes at least one lens, and is sequentially arranged along an optical axis from an object side to a sensor side direction. The first lens group includes a first lens, a second lens, and a third lens, which are sequentially arranged along the optical axis from the object side to the sensor side direction. The second lens group includes a fourth lens and a fifth lens, which are sequentially arranged along the optical axis from the object side to the sensor side direction. The third lens group includes a sixth lens, a seventh lens, and an eighth lens, which are sequentially arranged along the optical axis from the object side to the sensor side direction. The second lens group and the third lens group are movable toward the sensor side direction (first mode) and toward the object side direction (third mode). The third lens has a negative (-) refractive power, the fourth lens has a positive (+) refractive power, and the fifth lens has a negative (-) refractive power. The third lens and the fourth lens include glass. The optical system satisfies the following formula: [Formula] 13 <EFL<29 (In the formula, EFL means the effective focal length (mm) of the optical system.)

Description

[Technical field]

[0001] The embodiments relate to an optical system, an optical module including the optical system, and a camera module. [Background technology]

[0002] The camera module photographs an object and stores the photographed object as an image or a video. The camera module is applicable to various applications. For example, the camera module may be manufactured in a very small size. Thus, the camera module may be applied to a portable device such as a smartphone, a tablet PC, or a laptop. The camera module may also be applied to a drone or a vehicle.

[0003] The camera module includes an imaging lens that forms an image, and an image sensor that converts the formed image into an electrical signal. The camera module can perform an autofocus (AF) function that automatically adjusts the distance between the image sensor and the imaging lens to align the focal length of the lens. The camera module can also perform a zooming function of zooming up or zooming out to increase or decrease the magnification of a distant object by using a zoom lens.

[0004] In addition, the camera module can correct or prevent image blur using image stabilization (IS) technology.

[0005] The most important component for the camera module to obtain an image is the imaging lens that forms an image. Recently, interest in high image quality and resolution has been increasing. Accordingly, research into the optical system including multiple lenses has been conducted. For example, research into using multiple imaging lenses having positive (+) or negative (-) refractive powers for the optical system with high performance has been conducted. However, including multiple lenses may increase the overall length of the optical system. In addition, it may be difficult to improve the optical characteristics and aberration characteristics of the optical system.

[0006] Meanwhile, when the optical system includes a plurality of lenses, the position of any one of the plurality of lenses can be controlled. Alternatively, the position of a lens group including two or more lenses can be controlled. This allows the optical system to perform a zoom or autofocus (AF) function. However, when the lens or the lens group performs the function, the movement distance of the lens or the lens group may be significantly increased. This may result in a device including the optical system requiring a large amount of energy. In addition, there is a problem that a design taking the movement distance into consideration is required.

[0007] Furthermore, when the optical system includes multiple lenses, the overall length or height of the optical system may increase depending on the thickness, spacing, or size of the multiple lenses, which may increase the thickness and size of a device including the optical system.

[0008] Therefore, there is a need for a new optical system and optical module that can solve the above-mentioned problems. Summary of the Invention [Problem to be solved by the invention]

[0009] The embodiments aim to provide an optical system having improved optical characteristics, and an optical module and a camera module including the optical system.

[0010] Another object of the present invention is to provide an optical system capable of providing images of various magnifications, an optical module including the same, and a camera module.

[0011] Another object of the present invention is to provide an optical system having a small size, and an optical module and a camera module including the optical system.

[0012] Another object of the present invention is to provide an optical system applicable to a folded camera having a small thickness, an optical module including the same, and a camera module. [Means for solving the problem]

[0013] An optical system according to an embodiment includes a first lens group, a second lens group, and a third lens group, each of which includes at least one lens, and is sequentially arranged along an optical axis from an object side to a sensor side direction. The first lens group includes a first lens, a second lens, and a third lens, which are sequentially arranged along the optical axis from the object side to the sensor side direction. The second lens group includes a fourth lens and a fifth lens, which are sequentially arranged along the optical axis from the object side to the sensor side direction. The third lens group includes a sixth lens, a seventh lens, and an eighth lens, which are sequentially arranged along the optical axis from the object side to the sensor side direction. The second lens group and the third lens group are movable toward the sensor side direction (first mode) and toward the object side direction (third mode). The third lens has a negative (-) refractive power, the fourth lens has a positive (+) refractive power, and the fifth lens has a negative (-) refractive power. The third lens and the fourth lens include glass. The optical system satisfies the following formula:

[0014] [Formula]

[0015] 13 <EFL<29

[0016] (EFL means the effective focal length (mm) of the optical system.) Effect of the Invention

[0017] The optical system, optical module, and camera module according to the embodiment have improved optical characteristics. In particular, the effective focal length EFL can be controlled by moving at least one of the lens groups, thereby obtaining an image with a desired magnification.

[0018] Additionally, the embodiment minimizes the distance traveled by the moving lens group, thereby reducing the power consumption required to move the lens group.

[0019] Furthermore, the embodiment has a constant TTL regardless of the magnification in the first to third modes, so that the optical system and the camera module including the same have a slim size.

[0020] In addition, at least one of the lenses of the optical system and camera module according to the embodiment has a non-circular shape, so that the optical system has improved optical performance and a small size.

[0021] In addition, the optical system and the camera module according to the embodiment include an optical path changing member, so that the optical system can be applied to a folded camera having a thin thickness, and a device including the camera module can be manufactured with a thin thickness. [Brief description of the drawings]

[0022] [Figure 1] FIG. 2 is a diagram illustrating the configuration of an optical system according to an embodiment operating in a first mode. [Diagram 2] FIG. 2 is a diagram for explaining the total track length (TTL) and back focal length (BFL) of an optical system operating in a first mode. [Diagram 3] FIG. 4 is a diagram illustrating the configuration of an optical system according to an embodiment operating in a second mode. [Figure 4]FIG. 2 is a diagram for explaining the total track length (TTL) and back focal length (BFL) of an optical system operating in a second mode. [Diagram 5] FIG. 13 is a diagram illustrating the configuration of an optical system according to an embodiment operating in a third mode. [Figure 6] FIG. 11 is a diagram for explaining a total track length (TTL) and a back focal length (BFL) of an optical system operating in a third mode. [Figure 7] FIG. 1 is a diagram illustrating a non-circular lens. [Figure 8] 1 is a table for explaining the first lens to the eighth lens of the optical system according to the first example. [Figure 9] 1 is a table for explaining the first lens to the eighth lens of the optical system according to the first example. [Figure 10] 1 is a table for explaining the first lens to the eighth lens of the optical system according to the first example. [Figure 11] 1 is a table for explaining the first lens to the eighth lens of the optical system according to the first example. [Figure 12] 1 is a table for explaining the first lens to the eighth lens of the optical system according to the first example. [Figure 13] 1 is a table for explaining the first lens to the eighth lens of the optical system according to the first example. [Figure 14] 1 is a table for explaining the first lens to the eighth lens of the optical system according to the first example. [Figure 15] 1 is a table for explaining the first lens to the eighth lens of the optical system according to the first example. [Figure 16] 1 is a table for explaining the first lens to the eighth lens of the optical system according to the first example. [Figure 17] 1 is a table for explaining the first lens to the eighth lens of the optical system according to the first example. [Figure 18] 4 is a graph of the MTF characteristic when the optical system according to the first example operates in the first mode. [Figure 19]4 is a graph showing aberration diagrams when the optical system according to the first example operates in the first mode. [Figure 20] 6 is a graph of the MTF characteristic when the optical system according to the first example operates in the second mode. [Figure 21] 6 is a graph showing an aberration diagram when the optical system according to the first example operates in the second mode. [Figure 22] 13 is a graph of the MTF characteristic when the optical system according to the first example operates in a third mode. [Figure 23] 11 is a graph showing an aberration diagram when the optical system according to the first example operates in a third mode. [Figure 24] 13 is a table for explaining the first lens to the eighth lens of the optical system according to the second example. [Diagram 25] 13 is a table for explaining the first lens to the eighth lens of the optical system according to the second example. [Figure 26] 13 is a table for explaining the first lens to the eighth lens of the optical system according to the second example. [Figure 27] 13 is a table for explaining the first lens to the eighth lens of the optical system according to the second example. [Figure 28] 13 is a table for explaining the first lens to the eighth lens of the optical system according to the second example. [Figure 29] 13 is a table for explaining the first lens to the eighth lens of the optical system according to the second example. [Diagram 30] 1 is a diagram showing a camera module according to an embodiment applied to a mobile terminal; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0024] However, the technical idea of ​​the present invention is not limited to some of the embodiments described, and may be embodied in various different forms, and one or more of the components of the embodiments may be selectively combined or substituted within the scope of the technical idea of ​​the present invention. In addition, terms (including technical and scientific terms) used in the embodiments of the present invention may be interpreted as meanings that are generally understood by those having ordinary skill in the art to which the present invention belongs, unless otherwise specifically defined and described, and commonly used terms such as terms defined in dictionaries may be interpreted in consideration of the contextual meaning of the related art. The terms used in the embodiments of the present invention are intended to describe the embodiments, and are not intended to limit the present invention. In this specification, the singular form may include the plural form unless otherwise specified in the phrase, and when it is described as "A and (and) at least one (or more) of B and C," it may include one or more of all combinations that can be combined with A, B, and C. In addition, terms such as first, second, A, B, (a), and (b) may be used to describe the components of the embodiments of the present invention. Such terms are used merely to distinguish a component from other components, and do not limit the nature, order, or sequence of the components. Furthermore, when a component is described as being "coupled," "coupled," or "connected" to another component, it includes not only the case where the component is directly coupled, coupled, or connected to the other component, but also the case where the component is "coupled," "coupled," or "connected" between the other component and the other component or by another component.

[0025] In addition, when described as being formed or disposed "above or below" each component, "above" or "below" includes not only the case where two components are in direct contact with each other, but also the case where one or more other components are formed or disposed between the two components. In addition, when described as "above or below," it can include not only the upper direction based on one component, but also the lower direction.

[0026] In the following description, the first lens means the lens closest to the object side. The last lens means the lens closest to the sensor side. Unless otherwise specified, the unit of the radius, effective diameter, thickness, distance, BFL (Back focal length), and TTL (Total track length or Total Top Length) of the lens is millimeters (mm). The shape of the lens is based on the optical axis of the lens. For example, the object side surface of a lens being convex is defined as the optical axis portion of the object side surface of the lens being convex. That is, it does not mean that the periphery of the optical axis of the object side surface of the lens is convex. Therefore, even if the object side surface of a lens is described as being convex, the periphery of the optical axis of the object side surface of the lens may be concave. The thickness and radius of curvature of the lens are measured based on the optical axis of the lens. The object side surface is defined as the surface of the lens facing the object side with respect to the optical axis. The sensor side (Image side) is defined as the surface of the lens facing the imaging surface with respect to the optical axis.

[0027] Also, the edge thicknesses of the lenses described below may be the thicknesses at the uncut edges.

[0028] 1 to 5, an optical system 1000 according to an embodiment includes a plurality of lenses.

[0029] In the drawings, the optical system 1000 includes eight lenses. However, the embodiment is not limited thereto. For convenience of explanation, the following description will be given assuming that the optical system 1000 includes eight lenses.

[0030] The optical system 1000 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, a seventh lens 170, and an eighth lens 180.

[0031] The first lens 110 to the eighth lens 180 are sequentially arranged in a direction from the object side to the sensor side.

[0032] The first lens 110 to the eighth lens 180 are sequentially arranged along an optical axis OA. Therefore, the centers of the first lens 110 to the eighth lens 180 can coincide with the optical axis OA of the optical system 1000.

[0033] Light corresponding to information of an object passes through the first lens 110 to the eighth lens 180 and enters the image sensor unit 300 .

[0034] Each of the first lens 110 to the eighth lens 180 includes an effective area and a non-effective area.

[0035] The effective area is defined as an area where optical characteristics are realized by the first lens 110 to the eighth lens 180. The effective area is an area through which the light passes. Also, the effective area is an area through which the incident light is refracted.

[0036] That is, the effective area can be the effective diameter of the first lens 110 to the eighth lens 180.

[0037] The non-effective area is disposed on the periphery of the effective area. That is, the areas of the first lens 110 to the eighth lens 180 excluding the effective area are the non-effective areas. The non-effective area may be an area into which the light does not enter. The non-effective area may be an area unrelated to the optical characteristics. Or, the non-effective area may be an area into which light enters but unrelated to the optical characteristics. Or, the non-effective area may be an area fixed to a barrel (not shown) that houses the lens. That is, the non-effective area may be a flange portion fixed to a barrel.

[0038] Also, the size of the effective area may have a measurement error of about ±0.4 mm depending on the measurement method, etc. For example, the size of the effective area may be 2 mm or less, 1 mm or less, or 0.3 mm or less of the inner diameter of the flange portion.

[0039] The optical system 1000 may include a diaphragm (not shown) for adjusting the amount of incident light. The diaphragm may be disposed between two adjacent lenses among the first lens 110 to the eighth lens 180. For example, the diaphragm may be disposed between the third lens 130 and the fourth lens 140.

[0040] Also, at least one of the first lens 110 to the eighth lens 180 may function as an aperture. For example, the object side surface or the sensor side surface of any one of the first lens 110 to the eighth lens 180 may function as an aperture. For example, the object side surface of the fourth lens 140 may function as an aperture.

[0041] The optical system 1000 forms an optical module 2000. For example, the optical module 2000 may include the optical system 1000, an optical path changing member disposed in front of the optical system 1000, an image sensor unit 300 disposed behind the optical system 1000, and a filter unit 500.

[0042] The image sensor unit 300 senses light. In detail, the image sensor unit 300 senses light that passes through the first lens 110 to the eighth lens 180 in sequence. For example, the image sensor unit 300 may include a Charge Coupled Device (CCD) or a Complementary Metal Oxide Semiconductor (CMOS).

[0043] The filter unit 500 is disposed between the optical system 1000 and the image sensor unit 300 .

[0044] The filter unit 500 is disposed between the lens closest to the image sensor unit 300 and the image sensor unit 300. That is, the filter unit 500 is disposed between the eighth lens 180 and the image sensor unit 300. For example, the filter unit 500 may include an infrared filter or an optical filter.

[0045] The filter unit 500 passes light in a set wavelength band. Also, the filter unit 500 filters light in an unset wavelength band. If the filter unit 500 includes an infrared filter, it can block radiant heat emitted from external light from being transferred to the image sensor unit 300. Also, the filter unit 500 can transmit visible light and reflect infrared light.

[0046] The optical module 2000 may include an optical path changing member (not shown).

[0047] The optical path changing member reflects light incident from the outside. This changes the path of the light. The optical path changing member may include a reflecting mirror or a prism. For example, the optical path changing member may include a right-angle prism. This allows the optical path changing member to reflect the path of the incident light at an angle of 90°. This allows the path of the light to be changed.

[0048] The optical path changing member may be disposed adjacent to the plurality of lenses on the object side. When the optical module 2000 includes the optical path changing member, the optical path changing member, the first lens 110, the second lens 120, the third lens 130, the fourth lens 140, the fifth lens 150, the sixth lens 160, the seventh lens 170, the eighth lens 180, the filter unit 500, and the image sensor unit 300 may be disposed in this order from the object side toward the sensor.

[0049] The optical path changing member changes the path of light incident from the outside to a set direction. For example, the optical path changing member can change the path of light incident in a first direction to the second direction in which the lenses are arranged. The second direction can be an optical axis direction.

[0050] When the optical module 2000 includes a light path changing member, the optical module 2000 may be applied to a folded camera. In particular, when the optical module 2000 includes the light path changing member, light incident in a direction perpendicular to a surface of an electronic device to which the optical module 2000 is applied may be changed to a direction parallel to the surface of the electronic device. Thus, the optical module 2000 may have a thin thickness. Therefore, the electronic device may be formed to have a thin thickness.

[0051] The lenses of the optical system 1000 can move in a forward and backward direction along the optical axis. In particular, at least one of the lenses can move toward the object side or the sensor side along the optical axis. This allows the optical system 1000 and the optical module 2000 to adjust the focal length in a low magnification mode and a high magnification mode.

[0052] 1 to 6, the lens is divided into a plurality of lens groups. In detail, the lens is divided into a first lens group G1 defined as a fixed group lens that does not move, and a second lens group G2 and a third lens group G3 defined as movable groups of lenses that move.

[0053] The first lens group G1 includes at least one lens. In particular, the first lens group G1 includes a plurality of lenses. In particular, the first lens group G1 includes a plurality of lenses spaced apart at a set interval. For example, the first lens group G1 may include the first lens 110, the second lens 120, and the third lens 130 spaced apart from each other.

[0054] The lenses of the first lens group G1 are fixed such that the distance between the lenses does not change with the change in operation from the first mode to the third mode. For example, the distance between the first lens 110 and the second lens 120 does not change with the change in operation from the first mode to the third mode. Also, the distance between the second lens 120 and the third lens 130 does not change with the change in operation from the first mode to the third mode.

[0055] The spacing between the multiple lenses is defined as the distance in the optical axis OA direction between the centers of adjacent lenses.

[0056] The second lens group G2 includes at least one lens. More specifically, the second lens group G2 includes a plurality of lenses. The number of lenses in the first lens group G1 and the number of lenses in the second lens group G2 may be the same or different. For example, the number of lenses in the second lens group G2 may be less than the number of lenses in the first lens group G1.

[0057] The second lens group G2 includes a plurality of lenses spaced apart from each other at a set interval, for example, the second lens group G2 may include the fourth lens 140 and the fifth lens 150 spaced apart from each other.

[0058] The lenses of the second lens group G2 are fixed such that the intervals between the lenses do not change with the operation changes of the first to third modes. For example, the interval between the fourth lens 140 and the fifth lens 150 does not change with the operation of the first to third modes. The intervals between the lenses are defined as the distance in the optical axis OA direction between the centers of adjacent lenses.

[0059] The third lens group G3 includes at least one lens. More specifically, the third lens group G3 includes a plurality of lenses. The number of lenses in the third lens group G3 and the number of lenses in the second lens group G2 may be the same or different. For example, the number of lenses in the third lens group G3 may be greater than the number of lenses in the second lens group G2.

[0060] The third lens group G3 may include a plurality of lenses spaced apart from one another, for example, the sixth lens 160, the seventh lens 170, and the eighth lens 180.

[0061] The lenses of the third lens group G3 are fixed such that the intervals between the lenses do not change with the change in operation from the first mode to the third mode. For example, the interval between the sixth lens 160 and the seventh lens 170 does not change with the change in operation from the first mode to the third mode. Also, the interval between the seventh lens 170 and the eighth lens 180 does not change with the change in operation from the first mode to the third mode. The intervals between the lenses are defined as the distance in the optical axis OA direction between the centers of adjacent lenses.

[0062] The second lens group G2 and the third lens group G3 move. In detail, the second lens group G2 and the third lens group G3 move along the optical axis direction. The second lens group G2 and the third lens group G3 move along the optical axis direction to approach the first lens group G1 or the image sensor unit 300. That is, the second lens group G2 and the third lens group G3 move along the optical axis direction to approach the object side or the sensor side.

[0063] For example, a driving member (not shown) is connected to the optical system 1000. The second lens group G2 and the third lens group G3 can move along the optical axis direction by the driving force of the driving member.

[0064] The driving member can move the second lens group G2 and the third lens group G3 by changing from the first mode to the third mode, whereby at least one of the intervals between the first lens group G1 and the second lens group G2, the interval between the first lens group G1 and the third lens group G3, the interval between the second lens group G2 and the image sensor unit 300, and the interval between the third lens group G3 and the image sensor unit 300 is changed and controlled.

[0065] The magnification in the first mode may mean a magnification of 4.8 times when a field angle of 85 degrees is taken as 1 time. The magnification in the second mode may mean a magnification of 6 times when a field angle of 85 degrees is taken as 1 time. The magnification in the third mode may mean a magnification of 8.5 times when a field angle of 85 degrees is taken as 1 time.

[0066] 1 to 6, the first lens group G1 may be fixed. The second lens group G2 and the third lens group G3 may be movable by the driving member. In this case, the intervals between the lenses of the first lens group G1, the second lens group G2, and the third lens group G3 may not change.

[0067] In detail, when the second lens group G2 and the third lens group G3 move, the interval between the fourth lens 140 and the fifth lens 150 of the second lens group G2, the interval between the sixth lens 160 and the seventh lens 170 of the third lens group G3, and the interval between the seventh lens 170 and the eighth lens 180 may be fixed regardless of the driving force. Thus, the total track length (TTL) of the optical module 2000 is maintained. Also, the back focal length (BFL) of the optical module 2000 changes depending on the driving force.

[0068] For example, the optical module 2000 may be changed from the first mode to the second mode. Or, the optical module 2000 may be changed from the first mode to the third mode. Or, the optical module 2000 may be changed from the second mode to the third mode. At this time, the second lens group G2 and the third lens group G3 may move from the image sensor unit 300 toward the first lens group G1. In particular, the second lens group G2 and the third lens group G3 may move to a position adjacent to the first lens group G1.

[0069] Conversely, the optical module 2000 may change from the third mode to the first mode. Or, the optical module 2000 may change from the third mode to the second mode. Or, the optical module 2000 may change from the second mode to the first mode. At this time, the second lens group G2 and the third lens group G3 may move from the first lens group G1 toward the image sensor unit 300. In particular, the second lens group G2 and the third lens group G3 may move to a position adjacent to the image sensor unit 300.

[0070] In addition, when the second lens group G2 and the third lens group G3 move, the composite focal length of the first lens 110 and the second lens 120 may be maintained. In addition, the composite focal length of the second lens 120 and the third lens 130 may be maintained. In addition, the composite focal length of the first lens 110, the second lens 120, and the third lens 130 may be maintained.

[0071] Furthermore, when the second lens group G2 and the third lens group G3 move, the composite focal length of the fourth lens 140 and the fifth lens 120 may be maintained.

[0072] In addition, when the second lens group G2 and the third lens group G3 move, the composite focal length of the sixth lens 160 and the seventh lens 170 may be maintained. In addition, the composite focal length of the seventh lens 170 and the eighth lens 180 may be maintained. In addition, the composite focal length of the sixth lens 160, the seventh lens 170, and the eighth lens 180 may be maintained.

[0073] In addition, when the second lens group G2 and the third lens group G3 move, the focal lengths of the third lens 130 and the fourth lens 140 may change. In addition, the focal lengths of the second lens 120, the third lens 130, and the fourth lens 140 may change. In addition, the focal lengths of the third lens 130, the fourth lens 140, and the fifth lens 150 may change. In addition, the focal lengths of the first lens 110, the second lens 120, the third lens 130, and the fourth lens 140 may change. In addition, the focal lengths of the second lens 120, the third lens 130, the fourth lens 140, and the fifth lens 150 may change.

[0074] In addition, when the second lens group G2 and the third lens group G3 move, the focal lengths of the fifth lens 150 and the sixth lens 160 may change. In addition, the focal lengths of the fourth lens 140, the fifth lens 150, and the sixth lens 160 may change. In addition, the focal lengths of the fifth lens 150, the sixth lens 160, and the seventh lens 170 may change. In addition, the focal lengths of the third lens 130, the fourth lens 140, the fifth lens 150, and the sixth lens 160 may change. In addition, the focal lengths of the fourth lens 140, the fifth lens 150, the sixth lens 160, and the seventh lens 170 may change.

[0075] That is, in the camera module including the optical module according to the embodiment, the position of at least one of the lens groups G1, G2, and G3 is controlled. This allows the distance between the lens groups G1, G2, and G3, the effective focal length EFL (Effective Focal Length) of the optical system 1000, and the composite focal length of the multiple lenses to be changed. This allows the camera module to control the effective focal length (EFL). In addition, the camera module can provide a zoom function at low, medium, and high magnifications for a subject.

[0076] The focal length EFL of the optical system changes due to the movement of the second lens group G2 and the third lens group G3.

[0077] For example, the effective focal length of the first mode may be 13 mm to 14 mm, the effective focal length of the second mode may be 20 mm to 21 mm, and the effective focal length of the third mode may be 28 mm to 29 mm.

[0078] That is, the effective focal length EFL of the optical system can vary within the range of 13 mm to 29 mm.

[0079] The first lens group G1, the second lens group G2, and the third lens group G3 have different refractive powers. For example, the first lens group G1 can have negative (-) refractive power. The second lens group G2 can have positive (+) refractive power. The third lens group G3 can have negative (-) refractive power.

[0080] The first lens group G1, the second lens group G2, and the third lens group G3 have different focal lengths. For example, the first lens group G1 and the second lens group G2 have refractive powers of opposite signs. As a result, the focal length of the second lens group G2 and the focal length of the first lens group G1 have opposite signs. In addition, the second lens group G2 and the third lens group G3 have refractive powers of opposite signs. As a result, the focal length of the second lens group G2 and the focal length of the third lens group G3 have opposite signs. In addition, the first lens group G1 and the third lens group G3 have refractive powers of the same sign. As a result, the focal length of the first lens group G1 has the same sign as the focal length of the third lens group G3.

[0081] The lenses included in the first lens group G1, the second lens group G2, and the third lens group G3 will be described below.

[0082] The first lens 110 may have a positive (+) refractive power on the optical axis. The first lens 110 may include a plastic or glass material. For example, the first lens 110 may include a plastic material.

[0083] The first lens 110 includes a first surface S1 defined as an object side surface and a second surface S2 defined as a sensor side surface. The first surface S1 may be convex with respect to the object side surface on the optical axis. The second surface S2 may be concave with respect to the sensor side surface on the optical axis. That is, the first lens 110 may have a meniscus shape that is convex toward the object side on the optical axis as a whole.

[0084] At least one of the first surface S1 and the second surface S2 may be aspheric. For example, the first surface S1 and the second surface S2 may both be aspheric.

[0085] The size of the effective diameter of the first surface S1 and the size of the effective diameter of the second surface S2 may be different. For example, the size of the effective diameter of the first surface S1 may be larger than the size of the effective diameter of the second surface S2.

[0086] The second lens 120 may have a positive (+) refractive power on the optical axis. The second lens 120 may include a plastic or glass material. For example, the second lens 120 may include a plastic material.

[0087] The second lens 120 includes a third surface S3 defined as an object side surface and a fourth surface S4 defined as a sensor side surface. The third surface S3 may be convex with respect to the object side surface on the optical axis. Also, the fourth surface S4 may be convex with respect to the sensor side surface on the optical axis. That is, the second lens 120 may have a meniscus shape that is convex with respect to the object side on the optical axis as a whole.

[0088] At least one of the third surface S3 and the fourth surface S4 may be aspheric. For example, the third surface S3 and the fourth surface S4 may both be aspheric.

[0089] The size of the effective diameter of the third surface S3 and the size of the effective diameter of the fourth surface S4 may be different. For example, the size of the effective diameter of the third surface S3 may be larger than the size of the effective diameter of the fourth surface S4.

[0090] The third lens 130 may have a negative (-) refractive power on the optical axis. The third lens 130 may include a plastic or glass material. For example, the third lens 130 may include a glass material.

[0091] The third lens 130 includes a fifth surface S5 defined as an object side surface and a sixth surface S6 defined as a sensor side surface. The fifth surface S5 may be concave with respect to the object side surface on the optical axis. Also, the sixth surface S6 may be concave with respect to the sensor side surface on the optical axis. That is, the third lens 130 may have a shape in which both surfaces are concave on the optical axis as a whole.

[0092] At least one of the fifth surface S5 and the sixth surface S6 may be aspheric, for example, both the fifth surface S5 and the sixth surface S6 may be aspheric.

[0093] The size of the effective diameter of the fifth surface S5 and the size of the effective diameter of the sixth surface S6 may be different. For example, the size of the effective diameter of the fifth surface S5 may be larger than the size of the effective diameter of the sixth surface S6.

[0094] The fourth lens 140 may have a positive (+) refractive power on the optical axis. The fourth lens 140 may include a plastic or glass material. For example, the fourth lens 140 may include glass.

[0095] The fourth lens 140 includes the seventh surface S7 defined as an object side surface and an eighth surface S8 defined as a sensor side surface. The seventh surface S7 may be convex with respect to the object side surface on the optical axis. Also, the eighth surface S8 may be convex with respect to the sensor side surface on the optical axis. That is, the fourth lens 140 may have both surfaces convex with respect to the optical axis as a whole.

[0096] At least one of the seventh surface S7 and the eighth surface S8 may be aspheric. For example, the seventh surface S7 and the eighth surface S8 may both be aspheric.

[0097] The size of the effective diameter of the seventh surface S7 and the size of the effective diameter of the eighth surface S8 may be different. For example, the size of the effective diameter of the seventh surface S7 may be larger than the size of the effective diameter of the eighth surface S8.

[0098] The fifth lens 150 may have a negative (-) refractive power on the optical axis. The fifth lens 150 may include a plastic or glass material. For example, the fifth lens 150 may include a plastic material.

[0099] The fifth lens 150 includes a ninth surface S9 defined as an object side surface and a tenth surface S10 defined as a sensor side surface. The ninth surface S9 may be convex with respect to the object side surface on the optical axis. Also, the tenth surface S10 may be concave with respect to the sensor side surface on the optical axis. That is, the fifth lens 150 may have a meniscus shape that is convex toward the object side on the optical axis as a whole.

[0100] At least one of the ninth surface S9 and the tenth surface S10 may be an aspheric surface, for example, both of the ninth surface S9 and the tenth surface S10 may be aspheric surfaces.

[0101] The size of the effective diameter of the ninth surface S9 and the size of the effective diameter of the tenth surface S10 may be different. For example, the size of the effective diameter of the ninth surface S9 may be larger than the size of the effective diameter of the tenth surface S10.

[0102] The sixth lens 160 may have a positive (+) refractive power on the optical axis. The sixth lens 160 may include a plastic or glass material. For example, the sixth lens 160 may include a plastic material.

[0103] The sixth lens 160 includes an eleventh surface S11 defined as an object side surface and a twelfth surface S12 defined as a sensor side surface. The eleventh surface S11 may be concave with respect to the object side surface on the optical axis. Also, the twelfth surface S12 may be convex with respect to the sensor side surface on the optical axis. That is, the sixth lens 160 may have a meniscus shape that is convex toward the sensor side on the optical axis as a whole.

[0104] At least one of the eleventh surface S11 and the twelfth surface S12 may be an aspheric surface, for example, both of the eleventh surface S11 and the twelfth surface S12 may be aspheric surfaces.

[0105] The effective diameter size of the eleventh surface S11 and the effective diameter size of the twelfth surface S12 may be different. For example, the effective diameter size of the eleventh surface S11 may be smaller than the effective diameter size of the twelfth surface S12.

[0106] The seventh lens 170 may have a negative (-) refractive power on the optical axis. The seventh lens 170 may include a plastic or glass material. For example, the seventh lens 170 may include a plastic material.

[0107] The seventh lens 170 includes a thirteenth surface S13 defined as an object side surface and a fourteenth surface S14 defined as a sensor side surface. The thirteenth surface S13 may be concave with respect to the object side surface on the optical axis. Also, the fourteenth surface S14 may be convex with respect to the sensor side surface on the optical axis. That is, the seventh lens 170 may have a meniscus shape that is convex toward the sensor side on the optical axis as a whole.

[0108] At least one of the thirteenth surface S13 and the fourteenth surface S14 may be an aspheric surface, for example, both the thirteenth surface S13 and the fourteenth surface S14 may be aspheric surfaces.

[0109] The size of the effective diameter of the thirteenth surface S13 and the size of the effective diameter of the fourteenth surface S14 may be different. For example, the size of the effective diameter of the thirteenth surface S13 may be larger than the size of the effective diameter of the fourteenth surface S14.

[0110] The eighth lens 180 may have a positive (+) refractive power on the optical axis. The eighth lens 180 may include a plastic or glass material. For example, the eighth lens 180 may include a plastic material.

[0111] The eighth lens 180 includes a fifteenth surface S15 defined as an object side surface and a sixteenth surface S16 defined as a sensor side surface. The fifteenth surface S15 may be concave with respect to the object side surface on the optical axis. The sixteenth surface S16 may be convex with respect to the sensor side surface on the optical axis. That is, the eighth lens 180 may have a meniscus shape that is convex toward the sensor side on the optical axis as a whole.

[0112] At least one of the fifteenth surface S15 and the sixteenth surface S16 may be an aspheric surface, for example, both the fifteenth surface S15 and the sixteenth surface S16 may be aspheric surfaces.

[0113] The size of the effective diameter of the 15th surface S15 and the size of the effective diameter of the 16th surface S16 may be different. For example, the size of the effective diameter of the 15th surface S15 may be smaller than the size of the effective diameter of the 16th surface S16.

[0114] At least one lens among the plurality of lenses may have a non-circular shape. For example, at least one lens among the lenses of the first lens group G1 may have a non-circular shape. Or, at least one lens among the lenses of the second lens group G2 may have a non-circular shape. Or, at least one lens among the lenses of the third lens group G3 may have a non-circular shape.

[0115] For example, the first lens 110 may have a non-circular shape. In particular, the first surface S1 and the second surface S2 may have a non-circular shape. That is, when each of the first surface S1 and the second surface S2 is viewed from a front surface corresponding to the optical axis OA, the effective area of ​​each lens surface may have a non-circular shape.

[0116] Furthermore, the eighth lens 180 may have a non-circular shape. In particular, the fifteenth surface S15 and the sixteenth surface S16 may have a non-circular shape. That is, when each of the fifteenth surface S15 and the sixteenth surface S16 is viewed from a front surface corresponding to the optical axis OA, the effective area of ​​each lens surface may have a non-circular shape.

[0117] In addition, the second lens 120 may have a circular or noncircular shape. That is, the third surface S3 and the fourth surface S4 may have a circular or noncircular shape. That is, when each of the third surface S3 and the fourth surface S4 is viewed from the front corresponding to the optical axis OA, the effective area of ​​each lens surface may have a circular or noncircular shape.

[0118] The third lens 130 may have a circular shape. That is, the fifth surface S5 and the sixth surface S6 may have a circular shape. That is, when each of the fifth surface S5 and the sixth surface S6 is viewed from a front surface corresponding to the optical axis OA, the effective area of ​​each lens surface may have a circular shape.

[0119] In addition, the fourth lens 140 and the fifth lens 150 may have a circular or noncircular shape. That is, the seventh surface S7, the eighth surface S8, the ninth surface S9, and the tenth surface S10 may have a circular or noncircular shape. That is, when each of the seventh surface S7, the eighth surface S8, the ninth surface S9, and the tenth surface S10 is viewed from the front corresponding to the optical axis OA, the effective area of ​​each lens surface may have a circular or noncircular shape.

[0120] In addition, the sixth lens 160 and the seventh lens 170 may have a circular or noncircular shape. That is, the eleventh surface S11, the twelfth surface S12, the thirteenth surface S13, and the fourteenth surface S14 may have a circular or noncircular shape. That is, when each of the eleventh surface S11, the twelfth surface S12, the thirteenth surface S13, and the fourteenth surface S14 is viewed from the front corresponding to the optical axis OA, the effective area of ​​each lens surface may have a circular or noncircular shape.

[0121] 7 is a diagram for explaining a non-circular lens. For convenience of explanation, the first lens 110 has been mainly explained in FIG.

[0122] Referring to FIG. 7, each of the effective areas of the first surface S1 and the second surface S2 includes first to fourth edges A1, A2, A3, and A4.

[0123] The first edge A1 and the second edge A2 face each other in a first direction (x-axis direction) perpendicular to the optical axis OA. The first edge A1 and the second edge A2 may have a curved shape. The first edge A1 and the second edge A2 may have a curved shape having the same length or the same curvature. That is, the first edge A1 and the second edge A2 may be symmetrical with respect to a virtual line that passes through the optical axis OA and extends in a second direction (y-axis direction). The second direction (y-axis direction) is perpendicular to the optical axis OA and the first direction.

[0124] Also, the third edge A3 and the fourth edge A4 face each other in the second direction (y-axis direction). The third edge A3 and the fourth edge A4 connect the ends of the first edge A1 and the second edge A2. The third edge A3 and the fourth edge A4 may have a linear shape. The third edge A3 and the fourth edge A4 may have the same length and be parallel to each other. That is, the third edge A3 and the fourth edge A4 may be symmetrical with respect to a virtual line that passes through the optical axis OA and extends in the first direction (x-axis direction).

[0125] The first surface S1 and the second surface S2 include first to fourth edges A1, A2, A3, and A4, which allows the surface S1 to have a non-circular shape (for example, a D-cut shape).

[0126] The first surface S1 and the second surface S2 may have the non-circular shape during a process of manufacturing the first lens 110. For example, if the first lens 110 includes a plastic or glass material, the first lens 110 may be manufactured into the non-circular shape during an injection process.

[0127] Alternatively, the first lens 110 may be manufactured in a circular shape by an injection process. In a subsequent cutting process, a portion of the first surface S1 and the second surface S2 may be cut off. This allows the first lens 110 to have the third edge A3 and the fourth edge A4.

[0128] Thereby, each of the effective areas of the first surface S1 and the second surface S2 can have a set size. For example, a length CA of an imaginary first straight line passing through the optical axis OA and connecting the first edge A1 and the second edge A2 can be defined. Also, a length CH of an imaginary second straight line passing through the optical axis OA and connecting the third edge A3 and the fourth edge A4 can be defined.

[0129] The length CA of the virtual first straight line may be longer than the length CH of the virtual second straight line. The length CA of the first straight line means the size of the maximum effective diameter of each of the first surface S1 and the second surface S2. The length CH of the second straight line means the size of the minimum effective diameter of each of the first surface S1 and the second surface S2.

[0130] The first lens group G1, the second lens group G2, and the third lens group G3 may have different minimum effective diameters. In particular, the minimum effective diameter of the first lens group G1 may be larger than the minimum effective diameters of the second lens group G2 and the third lens group G3.

[0131] For example, the minimum effective diameter size of the first lens group G1 may be about 5.0 mm to 5.4 mm, and the minimum effective diameter size of the second lens group G2 and the third lens group G3 may be about 4.0 mm to 4.4 mm.

[0132] The optical system 1000 and the optical module 2000 according to the embodiment can satisfy at least one of the following formulas. As a result, the optical system 1000 and the optical module 2000 according to the embodiment can improve the aberration characteristics. Therefore, they have improved optical characteristics. In addition, the embodiment can effectively provide a zoom function for a desired magnification. In addition, they can have a slim and compact size.

[0133] [Formula 1]

[0134] 0.65 <CA_L4S1 / CA_L1S1<0.95

[0135] (The CA_L4S1 is the maximum effective diameter of the object side surface of the fourth lens. The CA_L1S1 is the maximum effective diameter of the object side surface of the first lens.)

[0136] The formula 1 is related to the decution ratio of the second lens group. When the optical system according to the embodiment satisfies the formula 1, the decution ratio of the fourth lens may be reduced.

[0137] [Formula 2]

[0138] 20 <V4-V5<80

[0139] (The V4 is the Abbe number of the fourth lens, and the V5 is the Abbe number of the fifth lens.)

[0140] The above formula 2 relates to the chromatic aberration of the optical system. When the optical system according to the embodiment satisfies the above formula 2, the chromatic aberration can be reduced.

[0141] [Formula 3]

[0142] 20 < V6 - V8 < 80

[0143] (Wherein V6 is the Abbe number of the sixth lens, and V8 is the Abbe number of the eighth lens.)

[0144] The formula 3 is related to the chromatic aberration of the optical system. When the optical system according to the embodiment satisfies the formula 3), the chromatic aberration can be reduced.

[0145] [Formula 4]

[0146] -25 < f123 < -5

[0147] (Wherein f123 is the combined focal length of the first lens, the second lens, and the third lens.)

[0148] The formula 4 is related to the peripheral light quantity ratio RI of the optical system and the size of the optical system. When the optical system according to the embodiment satisfies the formula 4, the peripheral light quantity ratio of the optical system can be reduced. Also, the diameter of the lens may decrease. Thereby, the optical system can have a compact size.

[0149] [Formula 5]

[0150] 2 < BFL1_1

[0151] (Wherein BFL_1 is the distance in the optical axis direction from the vertex of the sensor side surface of the last lens to the image plane of the image sensor when the second lens group and the third lens group move to the maximum moving distance in the first mode.)

[0152] The formula 5 is related to the size of the internal space of the optical system. When the optical system according to the embodiment satisfies the formula 5, a space for circuits and mechanical structures can be secured. Preferably, the formula 5 can satisfy 1 < BFL1_1 < 5.

[0153] [Formula 6]

[0154] -7 <f3<0

[0155] (The f3 is the focal length of the third lens.)

[0156] The formula 6 relates to the power of the first lens group and the size of the entrance pupil of the second lens group. When the optical system according to the embodiment satisfies the formula 6, the first lens group can have a negative (-) refractive power of a set range size. Also, the diameter of the entrance pupil of the lens of the second lens group can be set within a set range.

[0157] [Formula 7]

[0158] 0 <f4<7

[0159] (The f4 is the focal length of the fourth lens.)

[0160] The formula 7 is related to the lens diameter of the second lens group. When the optical system according to the embodiment satisfies the formula 7, the diameter of the fourth lens can be minimized.

[0161] [Formula 8]

[0162] -twenty five <f5<0

[0163] (The f5 is the focal length of the fifth lens.)

[0164] The formula 8 relates to the chromatic aberration of the second lens group of the optical system. When the optical system according to the embodiment satisfies the formula 8, the chromatic aberration of the second lens group may be reduced. This makes it possible to minimize the change in chromatic aberration among the first to third modes.

[0165] [Formula 9]

[0166] 3 <TTL / ImgH<5

[0167] (The TTL (Total track length) is the distance on the optical axis from the object side surface of the first lens to the image plane of the image sensor unit. The center of the image plane of the image sensor unit can be defined as the 0 field area. The ImgH means twice the value of the vertical distance of the optical axis OA from the 0 field area to 1.0 field. In other words, the ImgH means the diagonal length of the effective area of ​​the image sensor unit.)

[0168] The above formula 9 is related to the size of the optical system. When the optical system according to the embodiment satisfies the formula 9, the distance between the first lens and the image sensor unit can be controlled within a set range. Therefore, the optical system can have a compact size.

[0169] [Formula 10]

[0170] 2 <md1<7,

[0171] 2 <md2<7,

[0172] md1 <md2

[0173] (The md1 is a moving distance of the second lens group when changing from the first mode to the third mode, or from the third mode to the first mode. The md2 is a moving distance of the third lens group when changing from the first mode to the third mode, or from the third mode to the first mode.)

[0174] The formula 10 relates to the size of the optical system. When the optical system according to the embodiment satisfies the formula 10, the movement distance of the second lens group and the third lens group can be controlled within a set range. Therefore, the optical system can have a compact size.

[0175] [Formula 11]

[0176] 0.2 <BFL1_1 / BFL1_2<0.5

[0177] (BFL_1 is the optical axis direction distance from the apex of the sensor side of the last lens to the image surface of the image sensor when the second lens group and the third lens group move to the maximum movement distance in the first mode. BFL_2 is the optical axis direction distance from the apex of the sensor side of the last lens to the image surface of the image sensor when the second lens group and the third lens group move to the maximum movement distance in the third mode.)

[0178] The formula 11 relates to the size of the optical system. When the optical system according to the embodiment satisfies the formula 11, the BFL size according to the moving distance of the second lens group and the third lens group can be controlled within a set range. Therefore, the optical system can have a compact size.

[0179] [Formula 12]

[0180] 2.0 <EFL_2 / EFL_1<2.5

[0181] (The EFL_1 is the effective focal length in the first mode. The EFL_2 is the effective focal length in the second mode.)

[0182] The formula 12 relates to the magnification of the optical system. When the optical system according to the embodiment satisfies the formula 12, an image with low to high magnification can be realized depending on the moving distance of the second lens group and the third lens group.

[0183] [Formula 13]

[0184] 4.5 <F_2

[0185] 1.3 <F_2 / F_1<1.9

[0186] (The F_1 is the F-number in the first mode. The F_2 is the F-number in the third mode.)

[0187] The formula 13 is related to the resolving power of the optical system. When the optical system according to the embodiment satisfies the formula 13, it is possible to realize the resolving power within the ranges set in the first mode and the third mode.

[0188] [Formula 14]

[0189] N3>N1, N2, N4, N5, N6, N7, N8

[0190] (The N1 is the refractive index of the first lens. The N2 is the refractive index of the second lens. The N3 is the refractive index of the third lens. The N4 is the refractive index of the fourth lens. The N5 is the refractive index of the fifth lens. The N6 is the refractive index of the sixth lens. The N7 is the refractive index of the seventh lens. The N8 is the refractive index of the eighth lens.)

[0191] The formula 14 relates to the chromatic aberration and distortion of the optical system. When the optical system according to the embodiment satisfies the formula 14, the chromatic aberration and distortion can be reduced in the first to third modes.

[0192] [Formula 15]

[0193] 1.05 <N3 / N4<1.35

[0194] (The N3 is the refractive index of the third lens. The N4 is the refractive index of the fourth lens.)

[0195] The formula 15 relates to the chromatic aberration and distortion of the optical system. When the optical system according to the embodiment satisfies the formula 15, the chromatic aberration and distortion can be reduced in the first to third modes.

[0196] [Formula 16]

[0197] V4-V5>V8-V6,

[0198] V4-V5>V3-V1

[0199] (The V1 is the Abbe number of the first lens. The V3 is the Abbe number of the third lens. The V4 is the Abbe number of the fourth lens. The V5 is the Abbe number of the fifth lens. The V6 is the Abbe number of the sixth lens. The V8 is the Abbe number of the eighth lens.)

[0200] The formula 16 relates to the chromatic aberration of the optical system. When the optical system according to the embodiment satisfies the formula 16, the chromatic aberration can be reduced in the first to third modes.

[0201] [Formula 17]

[0202] 1 <CAL3S1 / CAL3S2<1.3

[0203] (CAL3S1 is the maximum effective diameter of the object side surface of the third lens. CAL3S2 is the maximum effective diameter of the sensor side surface of the third lens.)

[0204] The formula 17 is related to the decution ratio of the first lens group. When the optical system according to the embodiment satisfies the formula 17, the decution of the third lens can be eliminated.

[0205] [Formula 18]

[0206] 1.5 <CT1 / CG12<2.5

[0207] (The CT3 is the thickness of the third lens on the optical axis. The CG12 is the distance between the first lens and the second lens on the optical axis.)

[0208] The formula 18 relates to the optical performance of the optical system. When the optical system according to the embodiment satisfies the formula 18, the optical performance of the optical system can be maintained.

[0209] [Formula 19]

[0210] 13 <CT4 / CG45<18

[0211] (The CT4 is the thickness of the fourth lens on the optical axis. The CG45 is the distance between the fourth lens and the fifth lens on the optical axis.)

[0212] The above formula 19 relates to the optical performance of the optical system. When the optical system according to the embodiment satisfies the above formula 19, the optical performance of the optical system can be maintained.

[0213] [Formula 20]

[0214] 0.75 <CT8 / CG78<0.95

[0215] (The CT8 is the thickness of the eighth lens on the optical axis. The CG78 is the distance between the seventh lens and the eighth lens on the optical axis.)

[0216] The formula 20 relates to the optical performance of the optical system. When the optical system according to the embodiment satisfies the formula 20, the optical performance of the optical system can be maintained.

[0217] [Formula 21]

[0218] 4.5 <D123<4.9

[0219] (D123 is the distance in the optical axis direction from the vertex of the object side surface of the first lens to the vertex of the sensor side surface of the third lens.)

[0220] The above formula 21 is related to the size of the optical system. When the optical system according to the embodiment satisfies the above formula 21, the optical system can have a compact size.

[0221] [Formula 22]

[0222] 3.0 <D45<3.6

[0223] (The D45 is the distance in the optical axis direction from the vertex of the object side surface of the fourth lens to the vertex of the sensor side surface of the fifth lens.)

[0224] The above formula 22 is related to the size of the optical system. When the optical system according to the embodiment satisfies formula 22, the optical system can have a compact size.

[0225] [Formula 23]

[0226] 4.0 <D678<4.5

[0227] (D678 is the distance in the optical axis direction from the vertex of the object side surface of the sixth lens to the vertex of the sensor side surface of the eighth lens.)

[0228] The above formula 23 is related to the size of the optical system. When the optical system according to the embodiment satisfies the formula 23, the optical system can have a compact size.

[0229] [Formula 24]

[0230] 1.0 <CAL1S1 / CHL1S1<1.5

[0231] (The CAL1S1 is the maximum effective diameter of the object side surface of the first lens. The CHL1S1 is the minimum effective diameter of the object side surface of the first lens.)

[0232] The formula 24 is related to the decution ratio of the first lens group. When the optical system according to the embodiment satisfies the formula 24, the decution ratio of the first lens can be reduced.

[0233] [Formula 25]

[0234] 1.0 <CAL2S1 / CHL2S1<1.2

[0235] (The CAL2S1 is the maximum effective diameter of the object side surface of the second lens. The CHL2S1 is the minimum effective diameter of the object side surface of the second lens.)

[0236] The formula 25 is related to the decution ratio of the second lens group. When the formula 25 is satisfied, the optical system according to the embodiment can reduce the decution ratio of the third lens.

[0237] [Formula 26]

[0238] 1.0 <CAL4S1 / CHL4S1<1.3

[0239] (The CAL4S1 is the maximum effective diameter of the object side surface of the fourth lens. The CHL4S1 is the minimum effective diameter of the object side surface of the fourth lens.)

[0240] The formula 26 is related to the decution ratio of the second lens group. When the optical system according to the embodiment satisfies the formula 26, the decution ratio of the fourth lens can be reduced.

[0241] [Formula 27]

[0242] 1.0 <CAL5S1 / CHL5S1<1.2

[0243] (The CAL5S1 is the maximum effective diameter of the object side surface of the fifth lens. The CHL5S1 is the minimum effective diameter of the object side surface of the fifth lens.)

[0244] The formula 27 is related to the decution ratio of the second lens group. When the optical system according to the embodiment satisfies the formula 27, the decution ratio of the fifth lens can be reduced.

[0245] [Formula 28]

[0246] 1.0 <CAL8S1 / CHL8S1<1.3

[0247] (The CAL8S1 is the maximum effective diameter of the object side surface of the eighth lens. The CHL8S1 is the minimum effective diameter of the object side surface of the eighth lens.)

[0248] The formula 28 is related to the decution ratio of the third lens group. When the optical system according to the embodiment satisfies the formula 28, the decution ratio of the eighth lens can be reduced.

[0249] [Formula 29]

[0250] CAL4S1>CAL4S2,

[0251] CAL5S1>CAL5S2,

[0252] CAL7S1>CAL8S2,

[0253] CAL8S2>CAL8S1

[0254] (The CAL4S1 is the maximum effective diameter of the object side surface of the fourth lens. The CAL4S2 is the maximum effective diameter of the sensor side surface of the fourth lens. The CAL451 is the maximum effective diameter of the object side surface of the fifth lens. The CAL5S2 is the maximum effective diameter of the sensor side surface of the fifth lens. The CAL7S1 is the maximum effective diameter of the object side surface of the seventh lens. The CAL7S2 is the maximum effective diameter of the sensor side surface of the seventh lens. The CAL8S1 is the maximum effective diameter of the object side surface of the eighth lens. The CAL8S2 is the maximum effective diameter of the sensor side surface of the eighth lens.)

[0255] The formula 29 is related to the decution ratio of the third lens group. When the optical system according to the embodiment satisfies the formula 29, the decution ratio of the eighth lens can be reduced.

[0256] [Formula 30]

[0257] 1<|f1 / f3|<5

[0258] (The f1 is the focal length of the first lens. The f3 is the focal length of the third lens.)

[0259] The formula 30 is related to the resolving power of the optical system. When the optical system according to the embodiment satisfies the formula 30, the refractive powers of the first lens and the third lens can be controlled. This makes it possible to improve the resolving power of the optical system.

[0260] [Formula 31]

[0261] 1<|f5 / f4|<5

[0262] (The f4 is the focal length of the fourth lens. The f5 is the focal length of the fifth lens.)

[0263] The formula 31 is related to the resolving power of the optical system. When the optical system according to the embodiment satisfies the formula 31, the refractive power of the fourth lens and the fifth lens can be controlled. This can improve the resolving power of the optical system.

[0264] [Formula 32]

[0265] 1<|f5 / f4| / |f1 / f3|<1.3

[0266] The formula 32 relates to the resolving power of the optical system. When the optical system according to the embodiment satisfies the formula 32, the refractive powers of the first lens, the third lens, the fourth lens, and the fifth lens can be controlled. This makes it possible to improve the resolving power of the optical system.

[0267] [Formula 33]

[0268] 0 <f45<10,

[0269] -15 <f678<-5

[0270] (The f45 is the combined focal length of the fourth lens and the fifth lens. The f678 is the combined focal length of the sixth lens, the seventh lens, and the eighth lens.)

[0271] The formula 33 relates to the magnification of the optical system. When the optical system according to the embodiment satisfies the formula 33, the combined focal length of the second lens group and the third lens group can be controlled. This allows for improved resolution at a desired magnification.

[0272] [Formula 34]

[0273] 2.5<|f123 / f45|<5.5,

[0274] 0.5<|f123 / f678|<2.5

[0275] 1.5<|f678 / f45|<2.5

[0276] The formula 34 relates to the magnification of the optical system. When the optical system according to the embodiment satisfies the formula 34, the combined focal length of the second lens group and the third lens group can be controlled. This allows for improved resolution at a desired magnification.

[0277] [Formula 35]

[0278] 0<|Max_Distoriton|<5

[0279] (The Max_Distoriton is the maximum distortion size of the optical system.)

[0280] [Formula 36]

[0281] 4.5 <ImgH<7

[0282] [Formula 37]

[0283] JPEG2025500378000002.jpg1074

[0284] JPEG2025500378000003.jpg1075

[0285] (FOV(θ)_1 is the effective angle of view of the optical system in the first mode. FOV(θ)_2 is the effective angle of view of the optical system in the second mode.)

[0286] [Formula 38]

[0287] 1.0 <EG34_1 / CG34_1<1.3

[0288] 2.0 <EG34_2 / CG34_2<2.8

[0289] (CG34_1 is the distance in the optical axis between the third lens and the fourth lens in the first mode. The EG34_1 is the distance in the optical axis direction between the end of the effective area of ​​the third lens and the end of the effective area of ​​the fourth lens in the first mode. The CG34_2 is the distance in the optical axis between the third lens and the fourth lens in the second mode. The EG34_2 is the distance in the optical axis direction between the end of the effective area of ​​the third lens and the end of the effective area of ​​the fourth lens in the second mode.)

[0290] The formula 38 is related to the resolving power of the optical system. When the optical system according to the embodiment satisfies the formula 38, the lens thickness and the distance between the first lens group and the second lens group can be controlled. This allows the optical system to have an improved resolving power.

[0291] [Formula 39]

[0292] 1.0 <CG56_1 / EG56_1<1.4

[0293] 1.1 <CG56_2 / EG56_2<1.5

[0294] (The CG56_1 is the distance between the fifth lens and the sixth lens on the optical axis in the first mode. The EG56_1 is the distance between the end of the effective area of ​​the fifth lens and the end of the effective area of ​​the sixth lens in the optical axis direction in the first mode. The CG56_2 is the distance between the fifth lens and the sixth lens on the optical axis in the second mode. The distance is the distance between the end of the effective area of ​​the sixth lens in the optical axis direction.)

[0295] The formula 39 is related to the resolving power of the optical system. When the optical system according to the embodiment satisfies the formula 39, the lens thickness and the interval of the second lens group and the third lens group can be controlled. This allows the optical system to have an improved resolving power.

[0296] [Formula 40]

[0297] 3 <TTL / ImgH<5

[0298] The formula 40 is related to the size of the optical system. When the optical system according to the embodiment satisfies the formula 40, the optical system can have a compact size.

[0299] [Formula 41]

[0300] 0.40 <F_1 / EPD_1<75

[0301] 0.60 <F_2 / EPD_2<0.80

[0302] F_1 / EPD_1 <F_2 / EPD_2

[0303] (The F_1 is the F-number in the first mode. The F_2 is the F-number in the third mode. The EPD_1 is the entrance pupil in the first mode. The EPD_2 is the entrance pupil in the third mode.)

[0304] The formula 41 relates to the resolving power of the optical system. When the optical system according to the embodiment satisfies the formula 41, it can have improved resolving power in the first to third modes.

[0305] [Formula 42]

[0306] 1<|P3 / P4|<1.3,

[0307] (The P3 is the refractive power of the third lens. The P4 is the refractive power of the fourth lens.)

[0308] The formula 42 is related to the distortion of the optical system. When the optical system according to the embodiment satisfies the formula 42, the distortion of the optical system can be reduced.

[0309] [Formula 43]

[0310] 0 <CT_Lx / ET_Ly<3

[0311] 0 <ET_Lx / CT_Ly<3

[0312] (The CT_Lx is the thickness of the xth lens on the optical axis. The ET_Ly is the thickness of the yth lens at the end of the effective area. x is a natural number in the range of 1≦x≦8. y is a natural number in the range of 1≦y≦8. x=y is satisfied.)

[0313] The formula 43 is related to the manufacture of the optical system. When the optical system according to the embodiment satisfies the formula 43, the emission characteristics of the lens can be improved. This makes it possible to facilitate the lens manufacturing process.

[0314] [Formula 44]

[0315] 0 <CH_G1-CH_G2<1,

[0316] 0 <CH_G1-CH_G3<1

[0317] (The CH_G1 is the minimum effective diameter of the lens of the first lens group. The CH_G2 is the minimum effective diameter of the lens of the second lens group. The CH_G3 is the minimum effective diameter of the lens of the third lens group.)

[0318] The formula 44 is related to the size of the optical system. When the optical system according to the embodiment satisfies the formula 44, the optical system can have a compact size. Preferably, the formula 44 can satisfy 0.4 < CH_G1 - CH_G2 < 0.6, 0.4 < CH_G1 - CH_G3 < 0.6.

[0319] [Formula 45]

[0320] 0.5 < |md2 - md1| < 0.8

[0321] The formula 45 is related to the size of the optical system. When the optical system according to the embodiment satisfies the formula 45, the moving distances of the second lens group and the third lens group can be controlled within a set range. Thereby, the optical system can have a compact size.

[0322] [Formula 46]

[0323] 100 < V4 + V5 < 130,

[0324] V4 or V6 > 80

[0325] (The V4 is the Abbe number of the fourth lens. The V5 is the Abbe number of the fifth lens.)

[0326] The formula 46 is related to the chromatic aberration of the optical system. When the optical system according to the embodiment satisfies the formula 46, the chromatic aberration can be reduced by the difference in Abbe numbers between the fourth lens and the fifth lens.

[0327] [Formula 47]

[0328] |R1|, |R2|, |R3|, |R4|, |R5|, |R6|, |R7|, |R8|, |R10|, |R11|, |R12|, |R13|, |R14 |, |R15|, |R16|<|R9|,

[0329] 100<|R9| / |R10|<140

[0330] (The R1 is the radius of curvature of the object side surface of the first lens. The R2 is the radius of curvature of the sensor side surface of the first lens. The R3 is the radius of curvature of the object side surface of the second lens. The R4 is the radius of curvature of the sensor side surface of the second lens. The R5 is the radius of curvature of the object side surface of the third lens. The R6 is the radius of curvature of the sensor side surface of the third lens. The R7 is the radius of curvature of the object side surface of the fourth lens. The R8 is the radius of curvature of the sensor side surface of the fourth lens. The R9 is the radius of curvature of the object side surface of the fourth lens. is the radius of curvature of the sensor side surface of the fifth lens. R10 is the radius of curvature of the sensor side surface of the fifth lens. R11 is the radius of curvature of the object side surface of the sixth lens. R12 is the radius of curvature of the sensor side surface of the sixth lens. R13 is the radius of curvature of the object side surface of the seventh lens. R14 is the radius of curvature of the sensor side surface of the seventh lens. R15 is the radius of curvature of the object side surface of the eighth lens. R16 is the radius of curvature of the sensor side surface of the eighth lens.)

[0331] The formula 47 relates to the optical performance of the optical system. When the optical system according to the embodiment satisfies the formula 47, the optical performance of the optical system can be maintained.

[0332] [Formula 48]

[0333] 1 <TD_G1 / TD_G2<2

[0334] (The TD_G1 is the length of the first lens group. The TD_G2 is the length of the second lens group.)

[0335] The formula 48 is related to the size of the optical system. When the optical system according to the embodiment satisfies the formula 48, the optical system can have a compact size.

[0336] [Formula 49]

[0337] 0.8 <TD_G3 / TD_G2<1.5

[0338] (The TD_G2 is the length of the second lens group. The TD_G3 is the length of the third lens group.)

[0339] The formula 49 is related to the size of the optical system. When the optical system according to the embodiment satisfies the formula 49, the optical system can have a compact size.

[0340] [Formula 50]

[0341] 40 <Ave_ABV<50

[0342] (The Ave_ABV is the average of the Abbe numbers of the first lens to the eighth lens.)

[0343] The formula 50 relates to the chromatic aberration of the optical system. When the optical system according to the embodiment satisfies the formula 50, the chromatic aberration can be reduced.

[0344] [Formula 51]

[0345] 1.5 <Ave_Ind<1.8

[0346] (Ave_Ind is the average of the refractive indices of the first lens to the eighth lens.)

[0347] The formula 51 is related to the chromatic aberration of the optical system. When the optical system according to the embodiment satisfies the formula 51, the chromatic aberration can be reduced.

[0348] [Formula 52]

[0349] 1.5 <ET_L3 / CT_L3<2.5

[0350] (The ET_L3 is the thickness of the third lens at the end of its effective area. The CT_L3 is the thickness of the third lens at its optical axis.)

[0351] The formula 52 relates to the aberration of the optical system. When the optical system according to the embodiment satisfies the formula 52, the aberration characteristics can be improved. Therefore, the optical system has improved optical characteristics.

[0352] [Formula 53]

[0353] 2 <CT_L1 / ET_L1<3

[0354] (The CT_L1 is the thickness of the first lens at the optical axis. The ET_L1 is the thickness of the first lens at the end of its effective area.)

[0355] The formula 53 relates to the aberration of the optical system. When the optical system according to the embodiment satisfies the formula 53, the aberration characteristics can be improved. Therefore, the optical system has improved optical characteristics.

[0356] [Formula 54]

[0357] 2 <CT_L4 / ET_L4<3

[0358] (The CT_L4 is the thickness of the fourth lens at the optical axis. The ET_L4 is the thickness of the fourth lens at the end of its effective area.)

[0359] The formula 54 is related to the aberration of the optical system. When the optical system according to the embodiment satisfies the formula 54, the aberration characteristics can be improved. Therefore, the optical system has improved optical characteristics.

[0360] [Formula 55]

[0361] 2 <Air_CT_L7 / Air_ET_L7<4

[0362] (The Air_CT_L7 is the distance on the optical axis between the seventh lens and the eighth lens. The Air_ET_L7 is the distance between the end of the effective area of ​​the seventh lens and the end of the effective area of ​​the eighth lens.)

[0363] The formula 55 relates to the distortion of the optical system. When the optical system according to the embodiment satisfies the formula 55, the distortion in the first to third modes can be reduced.

[0364] [Formula 56]

[0365] 1 <Max_dia / Min_dia<1.7

[0366] (The Max_dia is the diameter of the lens with the largest effective diameter. The Min_dia is the diameter of the lens with the smallest effective diameter.)

[0367] The formula 56 is related to the aberration of the optical system. When the optical system according to the embodiment satisfies the formula 56, the aberration characteristics can be improved. Therefore, the optical system has improved optical characteristics.

[0368] [Formula 57]

[0369] 1 <Ave_Dia_G1 / Ave_Dia_G3<1.5

[0370] (The Ave_Dia_G1 is the average effective diameter of the lenses in the first lens group. The Ave_Dia_G3 is the average effective diameter of the lenses in the third lens group.)

[0371] The formula 57 relates to the aberration of the optical system. When the optical system according to the embodiment satisfies the formula 57, the aberration characteristics can be improved. Therefore, the optical system has improved optical characteristics.

[0372] [Formula 58]

[0373] 1 <Rdy_L1_S1 / Rdy_L4_S1<4

[0374] (The above-mentioned Rdy_L1_S1 is the radius of curvature of the first surface. The above-mentioned Rdy_L4_S1 is the radius of curvature of the seventh surface).

[0375] The formula 58 is related to the size of the optical system. When the optical system according to the embodiment satisfies the formula 58, the optical system can have a compact size.

[0376] [Formula 59]

[0377] 2 <Max_CT / Min_CT<8

[0378] (The Max_CT is the thickness of the lens that has the largest thickness at the optical axis. The Min_CT is the thickness of the lens that has the smallest thickness at the optical axis.)

[0379] The formula 59 is related to the size of the optical system. When the optical system according to the embodiment satisfies the formula 59, the optical system can have a compact size.

[0380] [Formula 60]

[0381] 0.7 <FOV(θ)_1 / Max_CRA_1<2,

[0382] 0.7 <FOV(θ)_2 / Max_CRA_2<2,

[0383] 0.7 <FOV(θ)_3 / Max_CRA_3<2,

[0384] (The FOV(θ)_1 is an effective angle of view of the optical system in the first mode. The FOV(θ)_2 is an effective angle of view of the optical system in the second mode. The FOV(θ)_3 is an effective angle of view of the optical system in the third mode. The Max_CRA_1 is a chief ray of the optical system in the first mode. The Max_CRA_2 is a chief ray of the optical system in the second mode. The Max_CRA_3 is a chief ray of the optical system in the third mode.)

[0385] The formula 60 is related to the aberration of the optical system. When the optical system according to the embodiment satisfies the formula 60, the aberration characteristics can be improved. Therefore, the optical system has improved optical characteristics.

[0386] The optical system 1000 and the optical module 2000 according to the embodiment satisfy at least one of the formulas. In particular, the optical system 1000 and the optical module 2000 may satisfy one or more of the formulas 1 to 60. The formulas 1 to 60 may be independent of each other. Alternatively, the formulas 1 to 60 may be related to each other.

[0387] As a result, the optical system 1000, the optical module 2000, and the camera module including the same have improved optical characteristics. Moreover, the embodiment satisfies at least one of the formulas 1 to 60. Therefore, chromatic aberration and distortion aberration can be reduced when realizing low-, medium-, and high-magnification images by moving the lens groups. Moreover, the optical system 1000, the optical module 2000, and the camera module including the same can have a slim size.

[0388] Hereinafter, a description will be given of an optical system and an optical module according to Example 1. In particular, a case will be described in which the first lens group G1 is fixed, and the second lens group G2 and the third lens group G3 are movable.

[0389] 8 and 9, the first lens 110 has a positive (+) refractive power. The first surface S1 is convex toward the object side surface on the optical axis. The second surface S2 is concave toward the sensor side surface on the optical axis. The first lens 110 has a meniscus shape convex toward the object side. The first surface S1 may be aspheric. The second surface S2 may be aspheric.

[0390] The first lens 110 may have a decut shape.

[0391] The second lens 120 has a positive (+) refractive power. The third surface S3 is convex toward the object side surface on the optical axis. The fourth surface S4 is concave toward the sensor side surface on the optical axis. The second lens 120 has a meniscus shape convex toward the object side. The third surface S3 may be aspheric. The fourth surface S4 may be aspheric.

[0392] The second lens 120 may have a decut shape.

[0393] The third lens 130 has negative (-) refractive power. The fifth surface S5 is concave toward the object side surface on the optical axis. The sixth surface S6 is concave toward the sensor side surface on the optical axis. The third lens 130 has a double-concave shape. The fifth surface S5 may be aspheric. The sixth surface S6 may be aspheric.

[0394] The fourth lens 140 has a positive (+) refractive power. The seventh surface S7 is convex toward the object side surface on the optical axis. The eighth surface S8 is convex toward the sensor side surface on the optical axis. The fourth lens 140 has a biconvex shape. The seventh surface S7 may be aspheric. The seventh surface S7 may be aspheric.

[0395] The fourth lens 140 may have a decut shape.

[0396] The fifth lens 150 has negative (-) refractive power. The ninth surface S9 is convex toward the object side surface on the optical axis. The tenth surface S10 is concave toward the sensor side surface on the optical axis. The fifth lens 150 has a meniscus shape convex toward the object side. The ninth surface S9 may be aspheric. The tenth surface S10 may be aspheric.

[0397] The fifth lens 150 may have a decut shape.

[0398] The sixth lens 160 has a positive (+) refractive power. The eleventh surface S11 is concave with respect to the object side surface on the optical axis. The twelfth surface S12 is convex with respect to the sensor side surface on the optical axis. The sixth lens 160 has a meniscus shape convex toward the sensor side. The eleventh surface S11 may be aspheric. The twelfth surface S12 may be aspheric.

[0399] The sixth lens 160 may have a decut shape.

[0400] The seventh lens 170 has negative (-) refractive power. The thirteenth surface S13 is concave with respect to the object side surface on the optical axis. The fourteenth surface S14 is convex with respect to the sensor side surface on the optical axis. The seventh lens 170 has a meniscus shape convex toward the sensor side. The thirteenth surface S13 may be aspheric. The fourteenth surface S14 may be aspheric.

[0401] The seventh lens 170 may have a decut shape.

[0402] The eighth lens 180 has a positive (+) refractive power. The fifteenth surface S15 is concave with respect to the object side surface on the optical axis. The sixteenth surface S16 is convex with respect to the sensor side surface on the optical axis. The eighth lens 180 has a meniscus shape convex toward the sensor side. The fifteenth surface S15 may be aspheric. The sixteenth surface S16 may be aspheric.

[0403] The eighth lens 180 may have a decut shape.

[0404] 1 to 6, the first lens group G1 is fixed. The second lens group G2 and the third lens group G3 are movable. As a result, the camera module is driven in the first to third modes to obtain information about a subject. For example, the second lens group G2 and the third lens group G3 are moved to the object side and the sensor side by the driving member. As a result, the camera module obtains information about a subject from low magnification to high magnification.

[0405] For example, the camera module operates in the first mode. The first lens group G1 is fixed, and the second lens group G2 and the third lens group G3 are moved by the driving member. In the first mode, the second lens group G2 and the third lens group G3 are disposed at a first position. At this time, if the initial positions of the second lens group G2 and the third lens group G3 are not at the first position, the second lens group G2 and the third lens group G3 are moved to the first position. That is, the second lens group G2 is disposed in an area separated from the first lens group G1 by the driving member at a first distance D1. Also, the third lens group G3 is disposed in an area separated from the second lens group G2 by a second distance D2 by the driving member. The first distance D1 is a center distance on the optical axis between the third lens 130 and the fourth lens 140. Also, the second distance D2 is a center distance on the optical axis between the fourth lens 140 and the fifth lens 150.

[0406] In contrast, when the initial positions of the second lens group G2 and the third lens group G3 are the first position, the second lens group G2 and the third lens group G3 are not moved and are disposed at the first position. As a result, the second lens group G2 is disposed in an area spaced apart from the first lens group G1 by a first distance D1. Also, the third lens group G3 is disposed in an area spaced apart from the second lens group G2 by a second distance D2.

[0407] Also, the camera module operates in a second mode. The first lens group G1 is fixed, and the second lens group G2 and the third lens group G3 are moved by the driving member. In the second mode, the second lens group G2 and the third lens group G3 are disposed at a second position. At this time, if the initial positions of the second lens group G2 and the third lens group G3 are not at the second position, the second lens group G2 and the third lens group G3 are moved to the second position. That is, the second lens group G2 is disposed in an area separated from the first lens group G1 by a third distance D3 by the driving member. Also, the third lens group G3 is disposed in an area separated from the second lens group G2 by a fourth distance D4 by the driving member. The third distance D3 is a center distance on the optical axis between the third lens 130 and the fourth lens 140. Also, the fourth distance D4 is a center distance on the optical axis between the fourth lens 140 and the fifth lens 150.

[0408] In contrast, when the initial positions of the second lens group G2 and the third lens group G3 are the second position, the second lens group G2 and the third lens group G3 are not moved and are disposed at the second position. As a result, the second lens group G2 is disposed in an area separated from the first lens group G1 by a third distance D3. Also, the third lens group G3 is disposed in an area separated from the second lens group G2 by a fourth distance D4.

[0409] Also, the camera module operates in the third mode. The first lens group G1 is fixed, and the second lens group G2 and the third lens group G3 are moved by the driving member. In the third mode, the second lens group G2 and the third lens group G3 are disposed at a third position. At this time, if the initial positions of the second lens group G2 and the third lens group G3 are not at the third position, the second lens group G2 and the third lens group G3 are moved to the third position. That is, the second lens group G2 is disposed in an area separated from the first lens group G1 by a fifth distance D5 by the driving member. Also, the third lens group G3 is disposed in an area separated from the second lens group G2 by a sixth distance D6 by the driving member. The fifth distance D5 is a center distance on the optical axis between the third lens 130 and the fourth lens 140. Also, the sixth distance D6 is a center distance on the optical axis between the fourth lens 140 and the fifth lens 150.

[0410] In contrast, when the initial positions of the second lens group G2 and the third lens group G3 are the third position, the second lens group G2 and the third lens group G3 are not moved and are disposed at the third position. As a result, the second lens group G2 is disposed in an area spaced apart from the first lens group G1 by a fifth distance D5. Also, the third lens group G3 is disposed in an area spaced apart from the second lens group G2 by a sixth distance D6.

[0411] The first to third lens groups have effective focal lengths and refractive powers as shown in Fig. 10. When operating in the first to third modes, the optical system 1000 has effective focal lengths EFL, TTL, BFL, angle of view, F number, EPD, and magnification as shown in Fig. 11.

[0412] Moreover, the first lens to the eighth lens have a thickness ratio as shown in Fig. 12. The optical axis thickness / edge thickness of the first lens to the eighth lens of the optical system 1000 is 3 or less. Alternatively, the edge thickness / optical axis thickness of the first lens to the eighth lens is 3 or less.

[0413] Referring to FIG. 13, the optical system 1000 has small chief ray angle differences among the first to third modes.

[0414] Fig. 14 is a table for explaining the aspheric coefficients of the first lens 110 to the eighth lens 180 of the optical system 1000. Figs. 15 and 16 are tables for explaining the sags of the first lens 110 to the eighth lens 180.

[0415] 15 and 16, the absolute value of sag may increase as the first lens 110 to the eighth lens 180 extend from the optical axis to the end of the effective area (effective diameter). In particular, the first lens 110 to the eighth lens 180 may have a monotonically increasing tendency in which the absolute value of sag increases as the first lens 110 to the eighth lens 180 extend from the optical axis to the end of the effective area (effective diameter).

[0416] As a result, no inflection points are formed on the surfaces of the first lens 110 to the eighth lens 180. Therefore, the first lens 110 to the eighth lens 180 can be manufactured easily.

[0417] 17 shows the decut ratio of the lenses having a non-circular shape among the first lens group G1, the second lens group G2, and the third lens group G3. The decut ratio means the ratio before and after decut when the minimum effective diameter size of the first lens group G1, the second lens group G2, and the third lens group G3 is to be satisfied with a set size. In detail, it is the ratio when the minimum effective diameter size of the first lens group G1 is 5.2 mm, and the minimum effective diameter size of the second lens group G2 and the third lens group G3 is 4.2 mm. That is, the decut ratio is defined as the CH / CA value of each lens.

[0418] Moreover, the optical system 1000 has excellent MTF characteristics in the first to third modes. Fig. 18 is a graph of the MTF characteristics of the optical system 1000 operating in the first mode. Fig. 20 is a graph of the MTF characteristics of the optical system 1000 operating in the second mode. Fig. 22 is a graph of the MTF characteristics of the optical system 1000 operating in the third mode.

[0419] Also, the optical system 1000 has excellent aberration characteristics. FIG. 19 is a graph of the aberration characteristics of the optical system 1000 operating in the first mode. FIG. 21 is a graph of the aberration characteristics of the optical system 1000 operating in the second mode. FIG. 23 is a graph of the aberration characteristics of the optical system 1000 operating in the third mode. FIG. 19, FIG. 21 and FIG. 23 are graphs of the spherical aberration, the astigmatic field curves and the distortion measured from left to right. In the graphs, the X-axis is the focal length (mm) and the distortion degree (%). The Y-axis is the image height. Also, the spherical aberration graph is a graph of light in the wavelength bands of about 435 nm, about 486 nm, about 546 nm, about 587 nm and about 656 nm. Moreover, the graphs of astigmatism and distortion are for light in the 546 nm wavelength band.

[0420] Hereinafter, an optical system and an optical module according to Example 2 will be described. In detail, a case will be described in which the first lens group G1 is fixed, and the second lens group G2 and the third lens group G3 are movable.

[0421] 24 and 25, the first lens 110 has a positive (+) refractive power. The first surface S1 is convex toward the object side surface on the optical axis. The second surface S2 is concave toward the sensor side surface on the optical axis. The first lens 110 has a meniscus shape convex toward the object side. The first surface S1 may be aspheric. The second surface S2 may be aspheric.

[0422] The first lens 110 may have a decut shape.

[0423] The effective diameter of the first lens 110 may be larger than the effective diameter of the other lenses.

[0424] The second lens 120 has a positive (+) refractive power. The third surface S3 is convex toward the object side surface on the optical axis. The fourth surface S4 is convex toward the sensor side surface on the optical axis. The second lens 120 has a shape having a biconvex shape. The third surface S3 may be aspheric. The fourth surface S4 may be aspheric.

[0425] The second lens 120 may have a decut shape.

[0426] The third lens 130 has negative (-) refractive power. The fifth surface S5 is concave toward the object side surface on the optical axis. The sixth surface S6 is concave toward the sensor side surface on the optical axis. The third lens 130 has a double-concave shape. The fifth surface S5 may be aspheric. The sixth surface S6 may be aspheric.

[0427] The third lens 130 may have a decut shape.

[0428] The fourth lens 140 has a positive (+) refractive power, which is greater than the refractive powers of the other lenses.

[0429] The seventh surface S7 is convex with respect to the object side surface at the optical axis. The eighth surface S8 is convex with respect to the sensor side surface at the optical axis. The fourth lens 140 has a biconvex shape. The seventh surface S7 may be aspheric. The seventh surface S7 may be aspheric.

[0430] The fourth lens 140 may have a decut shape.

[0431] Between the third lens 130 and the fourth lens 140, a diaphragm may be disposed.

[0432] The fifth lens 150 has negative (-) refractive power. The ninth surface S9 is concave with respect to the object side surface on the optical axis. The tenth surface S10 is concave with respect to the sensor side surface on the optical axis. The fifth lens 150 has a double-concave shape. The ninth surface S9 may be aspheric. The tenth surface S10 may be aspheric.

[0433] The fifth lens 150 may have a decut shape.

[0434] The sixth lens 160 has a positive (+) refractive power. The eleventh surface S11 is concave with respect to the object side surface on the optical axis. The twelfth surface S12 is convex with respect to the sensor side surface on the optical axis. The sixth lens 160 has a meniscus shape convex toward the sensor side. The eleventh surface S11 may be aspheric. The twelfth surface S12 may be aspheric.

[0435] The sixth lens 160 may have a decut shape.

[0436] The seventh lens 170 has negative (-) refractive power. The thirteenth surface S13 is concave with respect to the object side surface on the optical axis. The fourteenth surface S14 is concave with respect to the sensor side surface on the optical axis. The seventh lens 170 has a double-concave shape. The thirteenth surface S13 may be aspheric. The fourteenth surface S14 may be aspheric.

[0437] The seventh lens 170 may have a decut shape.

[0438] The effective diameter of the seventh lens 170 may be smaller than the effective diameters of the other lenses.

[0439] The eighth lens 180 has negative (-) refractive power. The fifteenth surface S15 is convex toward the object side surface on the optical axis. The sixteenth surface S16 is concave toward the sensor side surface on the optical axis. The eighth lens 180 has a meniscus shape convex toward the object side. The fifteenth surface S15 may be aspheric. The sixteenth surface S16 may be aspheric.

[0440] The eighth lens 180 may have a decut shape.

[0441] At least one of the first lens 110 to the eighth lens 180 may include glass. For example, the third lens 130 and the fourth lens 140 may include glass. This may reduce the overall length of the optical system.

[0442] The zoom magnification of the optical system may be 1.5 times or more.

[0443] When operating in the first to third modes, the minimum spacing between the lenses of the first lens group to the third lens group may be 0.2 mm to 8 mm.

[0444] The first to third lens groups have lengths and refractive powers as shown in Fig. 26. When operating in the first to third modes, the optical system 1000 has effective focal lengths EFL, TTL, BFL, angle of view, F number, EPD, and TD as shown in Fig. 27. The TD is the length from the first surface to the sixteenth surface.

[0445] Moreover, the first lens to the eighth lens have a thickness ratio as shown in Fig. 28. The optical axis thickness / edge thickness of the first lens to the eighth lens of the optical system 1000 is 3 or less. Alternatively, the edge thickness / optical axis thickness of the first lens to the eighth lens is 3 or less.

[0446] 29 shows the decution ratio of the lenses having a non-circular shape among the first lens group G1, the second lens group G2, and the third lens group G3. The decution ratio means the ratio before and after decution when the minimum effective diameter size of the first lens group G1, the second lens group G2, and the third lens group G3 is to be satisfied with a set size.

[0447] FIG. 30 is a diagram showing a mobile terminal to which a camera module according to an embodiment is applied.

[0448] Referring to FIG. 30, the mobile terminal 1 may include a camera module 10 disposed on the rear surface.

[0449] The camera module 10 may include an image capturing function, and may include at least one of an auto focus function, a zoom function, and an OIS function.

[0450] The camera module 10 can process still images or video frames obtained by an image sensor in a photographing mode or a video call mode. The processed image frames can be displayed on a display unit (not shown) of the mobile terminal 1 or can be stored in a memory (not shown). Although not shown in the drawings, the camera module can also be disposed on the front side of the mobile terminal 1.

[0451] For example, the camera module 10 may include a first camera module 10A and a second camera module 10B. At this time, at least one of the first camera module 10A and the second camera module 10B may include the optical system 1000. As a result, the camera module 10 may have improved optical characteristics. Also, an autofocus (AF) function may be provided for a subject located at a close distance of infinity to 40 mm or less. Also, the optical system 1000 may minimize the amount of movement of the lens group. As a result, the camera module may operate with low power. Also, the amount of curvature caused by the movement may be minimized. Also, the camera module may have a compact size.

[0452] The mobile terminal 1 may further include an autofocus device 31. The autofocus device 31 may include an autofocus function using a laser. The autofocus device 31 may be used under conditions where the autofocus function using an image of the camera module 10 is degraded. For example, the autofocus device 31 may be used at a close distance of 10 m or less or in a dark environment. The autofocus device 31 may include a light emitting unit including a vertical cavity surface emitting laser (VCSEL) semiconductor element and a light receiving unit such as a photodiode that converts optical energy into electrical energy.

[0453] The mobile terminal 1 may further include a flash module 33. The flash module 33 may include a light emitting element therein. The flash module 33 may be operated by the camera of the mobile terminal or by a user's control.

[0454] The features, structures, effects, etc. described in the above embodiments are included in at least one embodiment of the present invention, and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects, etc. exemplified in each embodiment can be combined or modified in other embodiments by a person having ordinary skill in the art to which the embodiment belongs. Therefore, the contents related to such combinations and modifications should be interpreted as being included in the scope of the embodiments of the present invention.

[0455] In addition, the above description is centered on the embodiment, but this is merely illustrative and does not limit the present invention. Those skilled in the art will understand that various modifications and applications not exemplified above are possible within the scope of the essential characteristics of the present embodiment. For example, each component specifically illustrated in the embodiment can be modified and implemented. Differences related to such modifications and applications should be interpreted as being included in the scope of the present invention defined in the appended claims.

Claims

1. a first lens group, a second lens group, and a third lens group, each of which includes at least one lens, arranged in sequence along an optical axis from an object side to a sensor side; the first lens group includes a first lens, a second lens, and a third lens that are sequentially arranged along the optical axis in a direction from the object side to the sensor side, the second lens group includes a fourth lens and a fifth lens sequentially arranged along the optical axis in a direction from the object side to the sensor side, the third lens group includes a sixth lens, a seventh lens, and an eighth lens that are sequentially arranged along the optical axis in a direction from the object side to the sensor side, the second lens group and the third lens group are movable toward the sensor side (first mode) and toward the object side (third mode); the third lens has a negative (-) refractive power, the fourth lens has a positive (+) refractive power, the fifth lens has a negative (−) refractive power, the third lens and the fourth lens include glass, The optical system satisfies the following formula: [Formula] 13<EFL<29 (In the formula, EFL means the effective focal length (mm) of the optical system.)

2. The optical system according to claim 1 , wherein the first lens and the eighth lens have a D-cut shape.

3. an object side surface of the first lens is convex toward the object side surface, the sensor side surface of the third lens is concave toward the sensor side surface, The optical system of claim 1 , wherein an object-side surface of the fourth lens is convex toward the object-side surface.

4. The optical system according to claim 1 , wherein the optical system satisfies the following formula: [Formula] 0<CT_Lx / ET_Ly<3 0<ET_Lx / CT_Ly<3 (In the formula, CT_Lx means the thickness of the xth lens on the optical axis, ET_Ly means the thickness of the yth lens at the end of the effective area, x is a natural number in the range of 1≦x≦8, y is a natural number in the range of 1≦y≦8, and x=y is satisfied.)

5. The optical system according to claim 1 , wherein the first lens group, the second lens group, and the third lens group satisfy the following formula: [Formula] 0<CH_G1−CH_G2<1 0<CH_G1−CH_G3<1 (In the formula, CH_G1 means the minimum size CH (clear height) of the effective diameter of the lens of the first lens group, CH_G2 means the minimum size CH (clear height) of the effective diameter of the lens of the second lens group, and CH_G3 means the minimum size CH (clear height) of the effective diameter of the lens of the third lens group.

6. a first lens group, a second lens group, and a third lens group, each of which includes at least one lens, arranged in sequence along an optical axis from an object side to a sensor side; the first lens group includes a first lens, a second lens, and a third lens that are sequentially arranged along the optical axis in a direction from the object side to the sensor side, the second lens group includes a fourth lens and a fifth lens sequentially arranged along the optical axis in a direction from the object side to the sensor side, the third lens group includes a sixth lens, a seventh lens, and an eighth lens that are sequentially arranged along the optical axis in a direction from the object side to the sensor side, the second lens group and the third lens group are movable toward the sensor side (first mode) and toward the object side (third mode); The optical system, wherein the first lens group, the second lens group, and the third lens group satisfy the following formula: [Formula] 1<TD_G1 / TD_G2<2 (The TD_G1 is the length of the first lens group. The TD_G2 is the length of the second lens group.)

7. The optical system according to claim 6 , wherein the first lens group, the second lens group, and the third lens group satisfy the following formula: [Formula] 0.8<TD_G3 / TD_G2<1.5 (The TD_G2 is the length of the second lens group. The TD_G3 is the length of the third lens group.)

8. The optical system according to claim 6 , wherein the first lens group, the second lens group, and the third lens group satisfy the following formula: [Formula] 40<Ave_ABV<50 (The Ave_ABV is the average of the Abbe numbers of the first lens to the eighth lens.)

9. The optical system according to claim 6 , wherein the first lens group, the second lens group, and the third lens group satisfy the following formula: [Formula] 1.5<Ave_Ind<1.8 (The Ave_Ind is the average of the refractive indices of the first lens to the eighth lens.)

10. The optical system according to claim 6 , wherein the first lens group, the second lens group, and the third lens group satisfy the following formula: [Formula] 0.7<FOV(θ)_1 / Max_CRA_1<2, 0.7<FOV(θ)_2 / Max_CRA_2<2, 0.7<FOV(θ)_3 / Max_CRA_3<2, (The FOV(θ)_1 is an effective angle of view of the optical system in the first mode. The FOV(θ)_2 is an effective angle of view of the optical system in the second mode. The FOV(θ)_3 is an effective angle of view of the optical system in the third mode. The Max_CRA_1 is a chief ray of the optical system in the first mode. The Max_CRA_2 is a chief ray of the optical system in the second mode. The Max_CRA_3 is a chief ray of the optical system in the third mode.)

Images