Optical system and camera module including the same

Abstract

The optical system disclosed in the embodiment includes first to fourth lens groups arranged along an optical axis from an object side to a sensor side, each including at least one lens, the first lens group having a refractive power opposite to that of the fourth lens group, the second lens group having a refractive power opposite to that of the third lens group, the first and fourth lens groups being fixed, and the second and third lens groups moving in the optical axis direction, each of the first and fourth lens groups including at least one lens having a non-circular shape, the non-circular lens having a non-circular ratio (CH / CA) greater than 0.7, the non-circular ratio being a ratio of a minimum effective diameter (Clear Height, CH) to a maximum effective diameter (Clear Aperture, CA) of a lens surface having a larger clear aperture (CA) on one of an object side surface and a sensor side surface of the non-circular lens, and the non-circular ratio of the lens included in the first lens group may be greater than the non-circular ratio of the lens included in the fourth lens group.

Description

[Technical Field]

[0001] Embodiments relate to optical systems for improved optical performance and camera modules including the same. [Background technology]

[0002] Camera modules, which capture images of objects and store them as images or videos, are used in a variety of applications. In particular, camera modules are manufactured to be ultra-compact and are used in portable devices such as smartphones, tablet PCs, and laptops, as well as drones and vehicles, providing a variety of functions. For example, the optical system of a camera module may include 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, which automatically adjusts the distance between the image sensor and the imaging lens to align the focal length of the lens, and a zoom function, which increases or decreases the magnification of distant objects to capture images. Camera modules also employ image stabilization (IS) technology to correct or prevent image blur caused by camera movement due to an unstable fixture or user movement. The most important element for such a camera module to obtain an image is the imaging lens that forms the image. Recently, interest in high resolution has been growing, and research into optical systems including multiple lenses to achieve this has been conducted. For example, research has been conducted into using multiple imaging lenses with positive (+) or negative (-) refractive power to achieve high resolution. However, when multiple lenses are included, it is difficult to derive excellent optical and aberration characteristics. Furthermore, when multiple lenses are included, the overall length and height increase depending on the thickness, spacing, size, etc. of the multiple lenses, which results in an increase in the overall size of the module including the multiple lenses.

[0003] Image sensors are becoming larger to achieve higher resolution and image quality. However, as the size of an image sensor increases, the total track length (TTL) of an optical system including multiple lenses also increases, resulting in an increase in the thickness of cameras, mobile terminals, and other devices that include the optical system. When an optical system includes multiple lenses, functions such as zoom and autofocus (AF) can be achieved by controlling the position of at least one lens or a lens group including at least one lens. However, when the lens or lens group performs these functions, the movement of the lens or lens group increases exponentially. This poses a problem in that the optical system requires a large amount of energy to move the lens or lens group and requires a large volume to accommodate the movement. Aberration characteristics deteriorate as the lens or lens group moves. This causes a problem in that optical characteristics deteriorate at certain magnifications when performing zoom and autofocus (AF) functions. Therefore, a new optical system that can solve these problems is needed. Summary of the Invention [Problem to be solved by the invention]

[0004] The embodiments provide an optical system with improved optical characteristics. The embodiments provide an optical system and a camera module capable of photographing at various magnifications. The embodiments provide an optical system and a camera module having improved aberration characteristics at various magnifications. The embodiments provide an optical system and a camera module that can be implemented in a small and compact manner. [Means for solving the problem]

[0005] An optical system according to an embodiment of the present invention includes first to fourth lens groups arranged along an optical axis from an object side to a sensor side, each including at least one lens, wherein the first lens group has a refractive power opposite to that of the fourth lens group, and the second lens group has a refractive power opposite to that of the third lens group, the first and fourth lens groups are fixed, and the second and third lens groups move in the optical axis direction, each of the first and fourth lens groups including at least one non-circular lens, the non-circular lens having a non-circular ratio (CH / CA) greater than 0.7, the non-circular ratio being a ratio of a minimum clear height (CH) to a maximum clear height (CA) of a lens surface having a larger clear aperture (CA) on one of the object side and the sensor side of the non-circular lens, and the non-circular ratio of at least one lens included in the first lens group may be greater than the non-circular ratio of at least one lens included in the fourth lens group.

[0006] According to the invention, the first lens group includes first to third lenses arranged sequentially along the optical axis from the object side to the sensor side, the second lens group includes fourth and fifth lenses arranged sequentially along the optical axis from the object side to the sensor side, the third lens group includes sixth and seventh lenses arranged sequentially along the optical axis from the object side to the sensor side, and the fourth lens group includes an eighth lens.

[0007] According to the invention, the fourth and fifth lenses may be circular lenses with a non-circularity ratio of 1. The first and second lenses may be non-circular lenses, and the non-circularity ratio of the first lens may be smaller than the non-circularity ratio of the second lens. The third lens may be a circular lens with a non-circularity ratio of 1. The third lens group may include at least one lens with a non-circular shape.

[0008] According to the invention, the sixth and seventh lenses are non-circular lenses, and the non-circularity ratio of the sixth lens may be greater than that of the seventh lens. The first lens has a positive refractive power, and the object side surface of the first lens can have a convex shape.

[0009] The optical system according to an embodiment of the invention includes first to fourth lens groups arranged along the optical axis in the direction from the object side to the sensor side, each including at least one lens. The first lens group has a refractive power opposite to that of the fourth lens group, the second lens group has a refractive power opposite to that of the third lens group, the first and fourth lens groups are fixed, the second and third lens groups move in the optical axis direction, each of the first and fourth lens groups includes at least one non-circular lens, the non-circularity ratio of at least one lens included in the second lens group is greater than the non-circularity ratio of the non-circular lenses included in each of the first and fourth lens groups, when the second and third lens groups are at the first position, it has a first magnification, and when it is at a second position different from the first position, it has a second magnification, and the second magnification may be greater than the first magnification.

[0010] According to the invention, when the second and third lens groups are at the first position, it can have a first effective focal length (EFL), and when it is at the second position, it can have a second effective focal length greater than the first effective focal length. m_G2 is the moving distance when the second lens group moves from the first position to the second position or from the second position to the first position, TTL (Total track length) is the distance on the optical axis from the object side surface of the lens closest to the object in the first lens group to the upper surface of the sensor, and the mathematical formula: 0.05 < m_G2 / TTL < 0.5 can be satisfied.

[0011] According to the invention, m_G3 is the moving distance when the third lens group moves from the first position to the second position or from the second position to the first position, TTL (Total track length) is the distance on the optical axis from the object side surface of the lens closest to the object in the first lens group to the upper surface of the sensor, and the mathematical formula: 0.05 < m_G3 / TTL < 0.5 can be satisfied.

[0012] According to an embodiment of the invention, when the second and third lens groups move from the first position to the second position or from the second position to the first position, the moving distance of the third lens group may be greater than the moving distance of the second lens group. When the second and third lens groups move from the first position to the second position or from the second position to the first position, the respective moving distances of the second and third lens groups can be 6 mm or less.

[0013] The camera module according to an embodiment of the invention includes the optical system and the driving member, and the driving member can control the positions of the second and third lens groups.

Effect of the Invention

[0014] The optical system and the camera module according to the embodiment have various magnifications and can have excellent optical characteristics when providing various magnifications. Specifically, the embodiment includes a plurality of lens groups including at least one lens, a part of the plurality of lens groups is fixed, and the rest are provided movably. At this time, the embodiment can control the moving distance of the moving lens group to have various magnifications and can provide an autofocus (AF) function for the subject. The optical system and the camera module according to the embodiment can correct the aberration characteristics of the plurality of lens groups or mutually complement the aberration characteristics that change by movement. Thereby, the optical system according to the embodiment can minimize or prevent the chromatic aberration change and the aberration characteristic change that occur when the magnification changes.

[0015] The optical system and camera module according to the embodiments may control the effective focal length (EFL) by moving only some of the lens groups, thereby minimizing the movement distance of the moving lens groups. As a result, the optical system may reduce the movement distance of the moving lens groups in response to a change in operation mode, thereby minimizing power consumption due to the movement of the lens groups. In the optical system, at least one lens included in the fixed group and the moving group may have a non-circular shape. As a result, the optical system may reduce the height of the optical system while maintaining optical performance, and may secure space for structurally arranging the lens groups disposed between the multiple lens groups.

[0016] The optical system and camera module according to the embodiment can adjust the magnification by moving a lens group other than the first lens group adjacent to the subject among a plurality of lens groups. As a result, the optical system can have a consistent TTL value even when the lens groups are moved in response to a change in magnification. Therefore, the optical system and the camera module including the same can be provided with a slimmer structure. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 2 is a diagram illustrating the configuration of an optical system according to an embodiment that operates in a first mode. [Figure 2] 1 is a diagram illustrating a lens having a non-circular shape. [Figure 3] 1 is a graph of the diffraction MTF of an optical system operating in a first mode. [Figure 4] 1 is a graph illustrating the aberration characteristics of an optical system operating in a first mode. [Figure 5] FIG. 10 is a diagram illustrating the configuration of an optical system according to an embodiment that operates in a second mode. [Figure 6] 10 is a graph of the diffraction MTF of an optical system operating in the second mode. [Figure 7] 10 is a graph illustrating the aberration characteristics of an optical system operating in a second mode. [Figure 8]FIG. 10 is a diagram illustrating the configuration of an optical system according to an embodiment that operates in a third mode. [Figure 9] 10 is a graph of the diffraction MTF of an optical system operating in the third mode. [Figure 10] 10 is a graph illustrating the aberration characteristics of an optical system operating in a third mode. [Figure 11] 1 is a diagram illustrating a camera module according to an embodiment applied to a mobile terminal; DETAILED DESCRIPTION OF THE INVENTION

[0018] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. The technical concept of the present invention is not limited to the described embodiments, but may be embodied in various forms. The elements of the embodiments may be selectively combined or substituted within the scope of the technical concept of the present invention. Furthermore, terms (including technical and scientific terms) used in the embodiments of the present invention shall be interpreted as generally understood by those skilled in the art, unless expressly specified otherwise. Commonly used terms, such as dictionary-defined terms, shall be interpreted in light of the context of the relevant technology. Furthermore, 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 "a," "an," or "an" may also include the plural form unless otherwise specified. For example, "at least one (or more) of A and B and C" refers to one or more of all possible combinations of A, B, and C. Furthermore, terms such as "first," "second," "A," "B," "(a)," and "(b)" may be used to describe elements of the embodiments of the present invention. Such terms are used to distinguish a component from other components and do not limit the nature or order of the components. When a component is described as being "coupled," "coupled," or "connected" to another component, this includes both cases where the component is directly coupled or connected to the other component and cases where another component is "coupled," "coupled," or "connected" between the two components. When a component is described as being formed or located "above or below" another component, "above or below" includes not only cases where the two components are in direct contact with each other, but also cases where one or more other components are formed or located between the two components. Furthermore, when the term "above or below" is used, it can mean not only the upper direction but also the lower direction relative to one component.

[0019] In the present invention, a convex lens surface may mean that the lens surface in the area corresponding to the optical axis is convex, and a concave lens surface may mean that the lens surface in the area corresponding to the optical axis is concave. The "object-side surface" may mean the lens surface facing the object side relative to the optical axis, and the "sensor-side surface" may mean the lens surface facing the imaging surface (image sensor) relative to the optical axis. The center thickness of the lens may mean the thickness of the lens in the optical axis direction relative to the optical axis. The vertical direction may mean the direction perpendicular to the optical axis, and the end of the lens or lens surface may mean the end of the effective area of ​​the lens through which incident light passes. The effective diameter of the lens surface may have a measurement error of up to ±0.4 mm depending on the measurement method, etc.

[0020] FIG. 1 is a diagram illustrating the configuration of an optical system according to an embodiment operating in a first mode, and FIG. 2 is a diagram illustrating a lens having a non-circular shape. Also, FIGS. 3 and 4 are graphs illustrating the diffraction MTF and aberration characteristics of the optical system operating in the first mode. FIG. 5 is a diagram illustrating the configuration of an optical system according to an embodiment operating in a second mode, and FIGS. 6 and 7 are graphs illustrating the diffraction MTF and aberration characteristics of the optical system operating in the second mode. FIG. 8 is a diagram illustrating the configuration of an optical system according to an embodiment operating in a third mode, and FIGS. 9 and 10 are graphs illustrating the diffraction MTF and aberration characteristics of the optical system operating in the third mode.

[0021] 1 to 10, an optical system 1000 according to an embodiment can include multiple lens groups. More specifically, the optical system 1000 includes multiple lens groups, each of which can include at least one lens. For example, the optical system 1000 can include a first lens group G1, a second lens group G2, a third lens group G3, and a fourth lens group G4, which are sequentially arranged along an optical axis OA from the object side toward the sensor. Each of the first to fourth lens groups G1, G2, G3, and G4 can have a positive (+) or negative (-) refractive power.

[0022] The first lens group G1 may have a refractive power opposite to that of the second lens group G2. For example, the first lens group G1 may have a negative (-) refractive power, and the second lens group G2 may have a positive (+) refractive power. The second lens group G2 may have a refractive power opposite to that of the third lens group G3. For example, the second lens group G2 may have a positive (+) refractive power, and the third lens group G3 may have a negative (-) refractive power. The third lens group G3 may have a refractive power opposite to that of the fourth lens group G4. For example, the third lens group G3 may have a negative (-) refractive power, and the fourth lens group G4 may have a positive (+) refractive power. The fourth lens group G4 may have a refractive power opposite to that of the first lens group G1.

[0023] The first lens group G1 and the second lens group G2 may have different focal lengths. Specifically, since the first and second lens groups G1 and G2 have opposite refractive powers as described above, the focal length of the second lens group G2 may have an opposite sign (+, -) to the focal length of the first lens group G1. For example, the focal length of the first lens group G1 may have a positive (+) sign, and the focal length of the second lens group G2 may have a negative (-) sign.

[0024] The second lens group G2 and the third lens group G3 may have different focal lengths. Specifically, since the second and third lens groups G2 and G3 have opposite refractive powers as described above, the focal length of the second lens group G2 may have an opposite sign (+, -) to the focal length of the third lens group G3. For example, the focal length of the second lens group G2 may have a negative (-) sign, and the focal length of the third lens group G3 may have a positive (+) sign.

[0025] The third lens group G3 and the fourth lens group G4 may have different focal lengths. Specifically, since the third and fourth lens groups G3 and G4 have opposite refractive powers as described above, the focal length of the third lens group G3 may have an opposite sign (+, -) to the focal length of the fourth lens group G4. For example, the focal length of the third lens group G3 may have a positive (+) sign, and the focal length of the fourth lens group G4 may have a negative (-) sign. That is, the fourth lens group G4 may have an opposite refractive power to the first lens group G1.

[0026] The absolute values ​​of the focal lengths of the first to fourth lens groups G1, G2, G3, and G4 can be larger in the order of the first lens group G1, the fourth lens group G4, the third lens group G3, and the second lens group G2.

[0027] In the optical system 1000, at least one of the first to fourth lens groups G1, G2, G3, and G4 is provided so as to be movable in the direction of the optical axis OA. More specifically, at least one of the lens groups G1, G2, G3, and G4 is provided so as to be movable, and the remaining lens groups are disposed at fixed positions. For example, among the lens groups G1, G2, G3, and G4, the first lens group G1 and the fourth lens group G4 are disposed at fixed positions, and the second lens group G2 and the third lens group G3 are provided so as to be movable in the direction of the optical axis OA. This allows the optical system 1000 to provide various magnifications by moving the lens groups.

[0028] The first to fourth lens groups G1, G2, G3, and G4 will be described in more detail below. The first lens group G1 may include at least one lens. The first lens group G1 may include multiple lenses. More specifically, the first lens group G1 may include two or more lenses having opposite refractive powers. For example, the first lens group G1 may include three lenses. The lenses included in the first lens group G1 may have a predetermined spacing. More specifically, the spacing between the lenses included in the first lens group G1 may be constant even when the operation mode (to be described later) changes. For example, the spacing between the first lens 110 and the second lens 120 and the spacing between the second lens 120 and the third lens 130 may be constant regardless of the operation mode. Here, the spacing between the lenses may refer to the spacing between adjacent lenses on the optical axis OA.

[0029] The second lens group G2 may include at least one lens. The second lens group G2 may include multiple lenses. Specifically, the second lens group G2 may include two or more lenses having opposite refractive powers. The number of lenses included in the second lens group G2 may be less than the number of lenses included in the first lens group G1. For example, the second lens group G2 may include two lenses. The lenses included in the second lens group G2 may have a predetermined spacing. Specifically, the spacing between the lenses included in the second lens group G2 may be constant even when the operation mode, which will be described later, changes. For example, the spacing between the fourth lens 140 and the fifth lens 150 may be constant regardless of the operation mode.

[0030] The third lens group G3 may include at least one lens. The third lens group G3 may include multiple lenses. More specifically, the third lens group G3 may include two or more lenses having opposite refractive powers. The number of lenses included in the third lens group G3 may be fewer than the number of lenses included in the first lens group G1. Alternatively, the number of lenses included in the third lens group G3 may be the same as the number of lenses included in the second lens group G2. For example, the third lens group G3 may include two lenses. The lenses included in the third lens group G3 may have a predetermined spacing. More specifically, the spacing between the lenses included in the third lens group G3 may be constant even when the operating mode, which will be described later, changes. For example, the spacing between the sixth lens 160 and the seventh lens 170 may be constant regardless of the operating mode.

[0031] The fourth lens group G4 may include at least one lens. The number of lenses included in the fourth lens group G4 may be less than the number of lenses included in the first lens group G1. The number of lenses included in the fourth lens group G4 may be less than or equal to the number of lenses included in the second lens group G2 and the third lens group G3. For example, the fourth lens group G4 may include one lens. The lenses included in the fourth lens group G4 may have a predetermined spacing. More specifically, the spacing between the lenses included in the fourth lens group G4 and the image sensor 300 may be constant and not change depending on the operation mode, which will be described later. Furthermore, if the fourth lens group G4 includes multiple lenses, the spacing between the multiple lenses may be constant and not change depending on the operation mode.

[0032] The optical system 1000 may include a plurality of lens groups G1, G2, G3, and G4 arranged sequentially from the object side toward the sensor. The optical system 1000 may also include a plurality of lenses 100 included in the lens groups G1, G2, G3, and G4, such as first to eighth lenses 110, 120, 130, 140, 150, 160, 170, and 180. In this case, the first lens group G1 may include the first to third lenses 110, 120, and 130, and the second lens group G2 may include the fourth and fifth lenses 140 and 150. The third lens group G3 may include the sixth and seventh lenses 160 and 170, and the fourth lens group G4 may include the eighth lens 180. The first to eighth lenses 110 , 120 , 130 , 140 , 150 , 160 , 170 , and 180 are sequentially arranged along the optical axis OA of the optical system 1000 .

[0033] Each of the plurality of lenses 100 may include an effective area and a non-effective area. The effective area may be an area through which light incident on each of the first to eighth lenses 110, 120, 130, 140, 150, 160, 170, and 180 passes. That is, the effective area may be an area where incident light is refracted to realize optical characteristics. The non-effective area is disposed around the effective area. The non-effective area may be an area on which the light does not enter. That is, the non-effective area may be an area unrelated to the optical characteristics. Furthermore, the non-effective area may be an area fixed to a barrel (not shown) that houses the lens.

[0034] The optical system 1000 may include an image sensor 300. The image sensor 300 may detect light. The image sensor 300 may detect light that has sequentially passed through the plurality of lenses 100, for example, the first to eighth lenses 110, 120, 130, 140, 150, 160, 170, and 180. The image sensor 300 may include a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS).

[0035] The optical system 1000 may further include a filter 500. The filter 500 is disposed between the plurality of lenses 100 and the image sensor 300. The filter 500 is disposed between the image sensor 300 and the fourth lens group G4, which is the lens group G1, G2, G3, and G4 and is closest to the image sensor 300. For example, the filter 500 is disposed between the eighth lens 180 of the fourth lens group G4 and the image sensor 300. The filter 500 may include at least one optical filter, such as an infrared filter or a cover glass. The filter 500 may transmit light of a predetermined wavelength band and filter out light of a different wavelength band. If the filter 500 includes an infrared filter, it may block radiant heat emitted from external light from being transmitted to the image sensor 300. The filter 500 may also transmit visible light and reflect infrared light.

[0036] The optical system 1000 may include a diaphragm (not shown). The diaphragm can adjust the amount of light incident on the optical system 1000. The diaphragm is located in front of the first lens 110 or between two lenses selected from the first to eighth lenses 110, 120, 130, 140, 150, 160, 170, and 180. For example, the diaphragm is located between the third lens 130 and the fourth lens 140.

[0037] At least one of the first to eighth lenses 110, 120, 130, 140, 150, 160, 170, and 180 may function as an aperture. For example, the object side surface or the sensor side surface of one selected from the first to eighth lenses 110, 120, 130, 140, 150, 160, 170, and 180 may function as an aperture to adjust the amount of light. For example, at least one of the sensor side surface (sixth surface S6) of the third lens 130 and the object side surface (seventh surface S7) of the fourth lens 140 may function as an aperture.

[0038] The optical system 1000 may further include an optical path changing member (not shown). The optical path changing member may reflect light incident from the outside to change 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. When the optical path changing member includes a right-angle prism, the optical path changing member may change the path of the light by reflecting the path of the incident light at a 90-degree angle. The optical path changing member is disposed adjacent to the object side of the lenses 100. That is, when the optical system 1000 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 500, and the image sensor 300 are disposed in this order from the object side toward the sensor. The optical path changing member may change the path of light incident from the outside to a predetermined direction. For example, the optical path changing member can change the path of light incident on the optical path changing member in a first direction to a second direction, which is the arrangement direction of the plurality of lenses 100 (the direction in which the plurality of lenses 100 are spaced apart, the direction of the optical axis OA in the drawing).

[0039] When the optical system 1000 includes a light path changing member, the optical system can be applied to a folding camera, thereby reducing the thickness of the camera. Specifically, when the optical system 1000 includes the light path changing member, light incident in a direction (first direction) perpendicular to the surface of a device to which the optical system 1000 is applied can be changed to a direction (second direction) parallel to the surface of the device. As a result, the optical system 1000 including the plurality of lenses 100 can have a thinner thickness within the device, thereby reducing the height of the device. For example, when the optical system 1000 does not include the light path changing member, the plurality of lenses 100 are arranged within the device, extending in the direction (first direction) perpendicular to the surface of the device. As a result, the optical system 1000 including the plurality of lenses 100 has a large height in the direction (first direction) perpendicular to the surface of the device, making it difficult to form the optical system 1000 and the device including the optical system 1000 thin.

[0040] However, when the optical system 1000 includes the optical path changing member, the plurality of lenses 100 are arranged to extend in a direction (second direction) parallel to the surface of the device. That is, the optical system 1000 is arranged so that the optical axis OA is parallel to the surface of the device, and can be applied to a folded camera. As a result, the optical system 1000 including the plurality of lenses 100 can have a low height in a direction perpendicular to the surface of the device. Therefore, a camera including the optical system 1000 can have a small thickness within the device, and the thickness of the device can also be reduced.

[0041] The light path changing member is disposed between two lenses of the plurality of lenses 100, or between the image sensor 300 and the last lens of the plurality of lenses 100 that is closest to the image sensor 300. A plurality of light path changing members may be provided. More specifically, a plurality of light path changing members may be disposed between the object and the image sensor 300. For example, the light path changing member may include a first light path changing member disposed adjacent to the object side of the plurality of lenses 100, and a second light path changing member disposed between the last lens and the image sensor 300. As a result, the optical system 1000 may have various shapes and heights depending on the camera to which it is applied, and may have improved optical performance.

[0042] To explain the plurality of lenses 100 again, the optical system 1000 may include first to eighth lenses 110, 120, 130, 140, 150, 160, 170, and 180 that are sequentially arranged along the optical axis OA from the object side toward the sensor. The first lens 110 is arranged closest to the object side among the plurality of lenses 100, and the eighth lens 180 is arranged closest to the image sensor 300 side.

[0043] The first lens 110 may have a positive refractive power along the optical axis OA. The first lens 110 may be made of plastic or glass. The first lens 110 may include 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 have a convex shape along the optical axis OA, and the second surface S2 may have a concave shape along the optical axis OA. That is, the first lens 110 may have a meniscus shape that bulges toward the object side along the optical axis OA. Alternatively, the first surface S1 may have a convex shape along the optical axis OA, and the second surface S2 may have a convex shape along the optical axis OA. That is, the first lens 110 may have a convex shape on both sides along the optical axis OA. At least one of the first surface S1 and the second surface S2 may be aspherical. For example, both the first surface S1 and the second surface S2 may be aspherical.

[0044] The second lens 120 may have positive (+) or negative (-) refractive power on the optical axis OA. The second lens 120 may be made of plastic or glass. The second lens 120 may include a third surface S3 defined as the object-side surface and a fourth surface S4 defined as the sensor-side surface. The third surface S3 may have a convex shape on the optical axis OA, and the fourth surface S4 may have a concave shape on the optical axis OA. That is, the second lens 120 may have a meniscus shape that bulges toward the object side on the optical axis OA. Alternatively, the third surface S3 may have a convex shape on the optical axis OA, and the fourth surface S4 may have a convex shape. That is, the second lens 120 may have a convex shape on both sides on the optical axis OA. Alternatively, the third surface S3 may have a concave shape on the optical axis OA, and the fourth surface S4 may have a convex shape on the optical axis OA. That is, the second lens 120 may have a meniscus shape that bulges toward the sensor on the optical axis OA. Alternatively, the third surface S3 may have a concave shape on the optical axis OA, and the fourth surface S4 may have a concave shape on the optical axis OA. That is, the second lens 120 may have concave shapes on both sides on the optical axis OA. At least one of the third surface S3 and the fourth surface S4 may be aspherical. For example, both the third surface S3 and the fourth surface S4 may be aspherical.

[0045] The third lens 130 may have a refractive power opposite to that of the first lens 110 along the optical axis OA. That is, the third lens 130 may have a negative (-) refractive power. The third lens 130 may include a plastic or glass material. The third lens 130 may include 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 have a convex shape along the optical axis OA, and the sixth surface S6 may have a concave shape along the optical axis OA. That is, the third lens 130 may have a meniscus shape that bulges toward the object side along the optical axis OA. Alternatively, the fifth surface S5 may have a concave shape along the optical axis OA, and the sixth surface S6 may have a concave shape along the optical axis OA. That is, the third lens 130 may have a concave shape on both sides along the optical axis OA. At least one of the fifth surface S5 and the sixth surface S6 may be aspherical. For example, the fifth surface S5 and the sixth surface S6 may both be aspherical.

[0046] In the first lens group G1, the first lens 110 closest to the object may have a refractive power opposite to that of the third lens 130 closest to the image sensor 300. As a result, the first lens group G1 can compensate for chromatic aberrations caused by the lenses 110, 120, and 130 included in the first lens group G1.

[0047] The third lens 130 in the first lens group G1, which is adjacent to the second lens group G2, may have the largest refractive index among the lenses in the first lens group G1. For example, the refractive index of the third lens 130 may be greater than 1.6. This allows the light provided from the first lens group G1 to the second lens group G2 to be controlled, and the size of the lenses in the second lens group G2 disposed after the first lens group G1 to be reduced.

[0048] The fourth lens 140 may have positive (+) or negative (-) refractive power on the optical axis OA. The fourth lens 140 may be made of plastic or glass. The fourth lens 140 may include a seventh surface S7 defined as the object-side surface and an eighth surface S8 defined as the sensor-side surface. The seventh surface S7 may have a convex shape on the optical axis OA, and the eighth surface S8 may have a concave shape on the optical axis OA. That is, the fourth lens 140 may have a meniscus shape that bulges toward the object side on the optical axis OA. Alternatively, the seventh surface S7 may have a convex shape on the optical axis OA, and the eighth surface S8 may have a convex shape on the optical axis OA. That is, the fourth lens 140 may have a convex shape on both sides on the optical axis OA. At least one of the seventh surface S7 and the eighth surface S8 may be aspherical. For example, both the seventh surface S7 and the eighth surface S8 may be aspherical.

[0049] The fifth lens 150 may have positive (+) or negative (-) refractive power along the optical axis OA. The fifth lens 150 may have a refractive power opposite to that of the fourth lens 140 along the optical axis OA. The fifth lens 150 may include a plastic or glass material. The fifth lens 150 may include a ninth surface S9 defined as the object-side surface and a tenth surface S10 defined as the sensor-side surface. The ninth surface S9 may have a convex shape along the optical axis OA, and the tenth surface S10 may have a concave shape along the optical axis OA. That is, the fifth lens 150 may have a meniscus shape that bulges toward the object side along the optical axis OA. Alternatively, the ninth surface S9 may have a convex shape along the optical axis OA, and the tenth surface S10 may have a convex shape along the optical axis OA. That is, the fifth lens 150 may have a convex shape on both sides along the optical axis OA. Alternatively, the ninth surface S9 may have a concave shape on the optical axis OA, and the tenth surface S10 may have a convex shape on the optical axis OA. That is, the fifth lens 150 may have a meniscus shape that bulges toward the sensor on the optical axis OA. Alternatively, the ninth surface S9 may have a concave shape on the optical axis OA, and the tenth surface S10 may have a concave shape on the optical axis OA. That is, the fifth lens 150 may have a concave shape on both sides on the optical axis OA. At least one of the ninth surface S9 and the tenth surface S10 may be aspherical. For example, both the ninth surface S9 and the tenth surface S10 may be aspherical.

[0050] In the second lens group G2, the fourth lens 140 closest to the object may have a refractive power opposite to that of the fifth lens 150 closest to the image sensor 300. In addition, the difference in Abbe number between the fourth lens 140 and the fifth lens 150 may be greater than 20. As a result, the second lens group G2 may minimize a change in chromatic aberration caused by a change in position according to a mode change.

[0051] The sixth lens 160 may have positive (+) or negative (-) refractive power on the optical axis OA. The sixth lens 160 may be made of plastic or glass. The sixth lens 160 may include an eleventh surface S11 defined as the object-side surface and a twelfth surface S12 defined as the sensor-side surface. The eleventh surface S11 may have a convex shape on the optical axis OA, and the twelfth surface S12 may have a concave shape on the optical axis OA. That is, the sixth lens 160 may have a meniscus shape that bulges toward the object side on the optical axis OA. Alternatively, the eleventh surface S11 may have a convex shape on the optical axis OA, and the twelfth surface S12 may have a convex shape on the optical axis OA. That is, the sixth lens 160 may have a biconvex shape on the optical axis OA. Alternatively, the eleventh surface S11 may have a concave shape on the optical axis OA, and the twelfth surface S12 may have a convex shape on the optical axis OA. That is, the sixth lens 160 may have a meniscus shape that bulges toward the sensor on the optical axis OA. Alternatively, the eleventh surface S11 may have a concave shape on the optical axis OA, and the twelfth surface S12 may have a concave shape on the optical axis OA. That is, the sixth lens 160 may have concave shapes on both sides on the optical axis OA. At least one of the eleventh surface S11 and the twelfth surface S12 may be aspherical. For example, both the eleventh surface S11 and the twelfth surface S12 may be aspherical.

[0052] The seventh lens 170 may have positive (+) or negative (-) refractive power on the optical axis OA. The seventh lens 170 may have a refractive power opposite to that of the sixth lens 160 on the optical axis OA. The seventh lens 170 may include plastic or glass. The seventh lens 170 may include a thirteenth surface S13 defined as the object-side surface and a fourteenth surface S14 defined as the sensor-side surface. The thirteenth surface S13 may have a convex shape on the optical axis OA, and the fourteenth surface S14 may have a concave shape on the optical axis OA. That is, the seventh lens 170 may have a meniscus shape that bulges toward the object side on the optical axis OA. Alternatively, the thirteenth surface S13 may have a convex shape on the optical axis OA, and the fourteenth surface S14 may have a convex shape on the optical axis OA. That is, the seventh lens 170 may have a convex shape on both sides on the optical axis OA. Alternatively, the thirteenth surface S13 may have a concave shape on the optical axis OA, and the fourteenth surface S14 may have a convex shape on the optical axis OA. That is, the seventh lens 170 may have a meniscus shape that bulges toward the sensor on the optical axis OA. Alternatively, the thirteenth surface S13 may have a concave shape on the optical axis OA, and the fourteenth surface S14 may have a concave shape on the optical axis OA. That is, the seventh lens 170 may have a concave shape on both sides on the optical axis OA. At least one of the thirteenth surface S13 and the fourteenth surface S14 may be aspherical. For example, both the thirteenth surface S13 and the fourteenth surface S14 may be aspherical.

[0053] In the third lens group G3, the sixth lens 160 closest to the object may have a refractive power opposite to that of the seventh lens 170 closest to the image sensor 300. In addition, the difference in Abbe number between the sixth lens 160 and the seventh lens 170 may be greater than 20. As a result, the third lens group G3 can minimize a change in chromatic aberration caused by a position change according to a mode change and act as an achromat.

[0054] The eighth lens 180 may have positive (+) refractive power on the optical axis OA. The eighth lens 180 may be made of plastic or glass. The eighth lens 180 may include a fifteenth surface S15 defined as the object-side surface and a sixteenth surface S16 defined as the sensor-side surface. The fifteenth surface S15 may have a convex shape on the optical axis OA, and the sixteenth surface S16 may have a convex shape on the optical axis OA. That is, the eighth lens 180 may have a convex shape on both sides on the optical axis OA. Alternatively, the eighth lens 180 may have a concave shape on the optical axis OA, and the sixteenth surface S16 may have a convex shape on the optical axis OA. That is, the eighth lens 180 may have a meniscus shape that bulges toward the sensor side on the optical axis OA. At least one of the fifteenth surface S15 and the sixteenth surface S16 may be aspherical. For example, the fifteenth surface S15 and the sixteenth surface S16 may both be aspherical surfaces.

[0055] The fourth lens group G4 may be the lens group G1, G2, G3, and G4 that is closest to the image sensor 300. In particular, the eighth lens 180 that is closest to the image sensor 300 may have the shortest light path among the lenses 100. The fourth lens group G4 may control the chief ray angle (CRA). More specifically, the CRA of the optical system 1000 according to the embodiment may be less than about 10 degrees, and the eighth lens 180 of the fourth lens group G4 may correct the chief ray angle (CRA) of light incident on the image sensor 300 to be close to 0 degrees.

[0056] At least one lens of the plurality of lenses 100 may have a non-circular shape, which will be described with reference to FIG.

[0057] Referring to FIG. 2, the lens may include an object-side surface and a sensor-side surface, and at least one of the lens surfaces may have a non-circular shape. For example, the effective area of ​​the lens surface may include first to fourth edges A1, A2, A3, and A4. The first edge A1 and the second edge A2 may be edges facing each other in a first direction (x-axis direction in FIG. 2) 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 and curvature. That is, the first edge A1 and the second edge A2 may have a symmetrical shape with respect to an imaginary line passing through the optical axis OA and extending in a second direction (y-axis direction in FIG. 2).

[0058] In the effective area of ​​the lens surface, the third edge A3 and the fourth edge A4 may be edges facing a second direction (y-axis direction in FIG. 2) perpendicular to the optical axis OA and the first direction. The third edge A3 and the fourth edge A4 may be edges connecting 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 have a symmetrical shape with respect to an imaginary line that passes through the optical axis OA and extends in the first direction (x-axis direction in FIG. 2).

[0059] The lens surface of the lens may have a non-circular shape, for example, a D-cut shape, by including the first to fourth edges A1, A2, A3, and A4. The non-circular lens surface may be formed during the lens manufacturing process. For example, if the lens is made of a plastic material, it may be manufactured into the non-circular shape during the injection molding process. Alternatively, the lens may be manufactured into a circular shape during the injection molding process, and the third and fourth edges A3 and A4 may be formed by cutting a portion of the lens in a subsequent cutting process.

[0060] As a result, the effective area of ​​the lens surface may have a predetermined size. For example, the length CA of an imaginary first straight line passing through the optical axis OA and connecting the first and second edges A1 and A2 may be longer than the length CH of an imaginary second straight line passing through the optical axis OA and connecting the third and fourth edges A3 and A4. Here, the length CA of the first straight line may represent the maximum clear aperture (CA) of the lens surface, and the length CH of the second straight line may represent the minimum clear height (CH) of the lens surface. Furthermore, if the effective area of ​​the lens surface is circular rather than non-circular, the maximum clear height CA and the minimum clear height CH of the lens surface may be the same.

[0061] At least one lens among the plurality of lenses 100 according to the embodiment may have a non-circular shape. Specifically, each of the first lens group G1 and the fourth lens group G4 may include at least one lens having a non-circular shape. For example, the first lens 110 of the first lens group G1 may have a non-circular shape. At least one lens surface among the first surface S1 and the second surface S2 of the first lens 110 may have a non-circular shape. Specifically, each effective area of ​​the first surface S1 and the second surface S2 may have a non-circular shape.

[0062] The first lens 110 may have a non-circularity ratio smaller than 1. Here, the non-circularity ratio of the first lens 110 may refer to the ratio (CH / CA) of the minimum effective diameter CH to the maximum effective diameter CA of the lens surface having the larger effective diameter CA between the object side surface (first surface S1) and the sensor side surface (second surface S2) of the first lens 110.

[0063] In the first lens 110 according to the embodiment, the first surface S1 may have a larger effective diameter than the second surface S2. The non-circularity ratio of the first lens 110 may be greater than 0.7. Specifically, the non-circularity ratio of the first lens 110 may be greater than 0.7 and less than 1. If the non-circularity ratio of the first lens 110 is less than 0.7, the height of the first lens 110 is reduced, resulting in a slimmer structure, but the area of ​​the effective area lost due to the non-circular shape increases, resulting in reduced optical performance. Furthermore, if the non-circularity ratio of the first lens 110 is 1 or greater, the first lens 110 may have a circular shape, making it difficult to achieve the effect of reducing the height of the first lens 110. Furthermore, the non-circularity ratio of the first surface S1 of the first lens 110 may be smaller than the non-circularity ratio of the second surface S2.

[0064] The second lens 120 of the first lens group G1 may have a non-circular shape. At least one of the third surface S3 and the fourth surface S4 of the second lens 120 may have a non-circular shape. Specifically, the effective area of ​​the third surface S3 may have a non-circular shape, and the effective area of ​​the fourth surface S4 may have a circular shape. The non-effective area of ​​the fourth surface S4 may have a non-circular shape.

[0065] The second lens 120 may have a non-circularity ratio (CH / CA) smaller than 1. Here, the non-circularity ratio of the second lens 120 may refer to the ratio (CH / CA) of the minimum effective diameter CH to the maximum effective diameter CA of the lens surface having the larger effective diameter CA between the object side surface (third surface S3) and the sensor side surface (fourth surface S4) of the second lens 120.

[0066] In the second lens 120 according to the embodiment, the third surface S3 may have a larger effective diameter than the fourth surface S4. The non-circularity ratio of the second lens 120 may be greater than 0.7. Specifically, the non-circularity ratio of the second lens 120 may be greater than 0.7 and less than 1. If the non-circularity ratio of the second lens 120 is less than 0.7, the height of the second lens 120 is reduced, resulting in a slimmer structure, but the area of ​​the effective area lost due to the non-circular shape increases, degrading optical performance. Furthermore, if the non-circularity ratio of the second lens 120 is 1 or greater, a circular shape would be obtained, making it difficult to achieve the effect of reducing the height of the second lens 120. Furthermore, the non-circularity ratio of the third surface S3 of the second lens 120 may be smaller than the non-circularity ratio of the fourth surface S4.

[0067] The non-circularity of the second lens 120 may be different from the non-circularity of the first lens 110. Specifically, the non-circularity of the second lens 120 may be greater than the non-circularity of the first lens 110. For example, the non-circularity of the second lens 120 may be about 1.05 times or more the non-circularity of the first lens 110. Specifically, the non-circularity of the second lens 120 may be about 1.1 times or more the non-circularity of the first lens 110 to control light incident on the first lens group G1.

[0068] The third lens 130 may have a circular or non-circular shape. More specifically, the fifth surface S5 and the sixth surface S6 of the third lens 130 may have a circular or non-circular shape. For example, the effective areas of the fifth surface S5 and the sixth surface S6 may each have a circular shape. The third lens 130 may have a non-circular ratio (CH / CA). Here, the non-circular ratio of the third lens 130 may refer to the ratio (CH / CA) of the minimum effective diameter CH to the maximum effective diameter CA of the lens surface having the larger effective diameter CA, either the object-side surface (fifth surface S5) or the sensor-side surface (sixth surface S6) of the third lens 130. The non-circular ratio of the third lens 130 may be greater than the non-circular ratios of the first and second lenses 110 and 120.

[0069] In the third lens 130 according to the embodiment, the fifth surface S5 may have a larger effective diameter than the sixth surface S6. The non-circularity ratio of the third lens 130 may be greater than 0.7. Specifically, the non-circularity ratio of the third lens 130 may be greater than 0.9 and less than 1.1. More specifically, the third lens 130 may be a circular lens having a circular effective area, and the non-circularity ratio may be 1. That is, the fifth surface S5 of the third lens 130 having a larger effective diameter may have the same maximum effective diameter CA and minimum effective diameter CH. Furthermore, the non-circularity ratio of the sixth surface S6 of the third lens 130 may be the same as the non-circularity ratio of the fifth surface S5. The non-circularity ratio of the third lens 130 may be different from the non-circularity ratios of the first and second lenses 110 and 120. Specifically, the non-circularity ratio of the third lens 130 may be greater than the non-circularity ratios of the first and second lenses 110 and 120.

[0070] The eighth lens 180 of the fourth lens group G4 may have a non-circular shape. At least one of a fifteenth surface S15 and a sixteenth surface S16 of the eighth lens 180 may have a non-circular shape. Specifically, the effective areas of the fifteenth surface S15 and the sixteenth surface S16 may each have a non-circular shape.

[0071] The eighth lens 180 may have a non-circularity ratio less than 1. Here, the non-circularity ratio of the eighth lens 180 may refer to the ratio (CH / CA) of the minimum effective diameter CH to the maximum effective diameter CA of the lens surface having the larger effective diameter CA between the object-side surface (fifteenth surface S15) and the sensor-side surface (sixteenth surface S16) of the eighth lens 180. In the eighth lens 180 according to the embodiment, the sixteenth surface S16 may have a larger effective diameter than the fifteenth surface S15. The non-circularity ratio of the eighth lens 180 may be greater than 0.7. More specifically, the non-circularity ratio of the eighth lens 180 may be greater than 0.7 and less than 1. When the non-circularity ratio of the eighth lens 180 is less than 0.7, the height of the eighth lens 180 is reduced, resulting in a slimmer structure; however, the area of ​​the effective area lost due to the non-circular shape is increased, resulting in reduced optical performance. Furthermore, if the non-circularity ratio of the eighth lens 180 is 1 or more, it is difficult to obtain the effect of reducing the height of the eighth lens 180 by making it a circular shape. Furthermore, the non-circularity ratio of the sixteenth surface S16 of the eighth lens 180 may be smaller than the non-circularity ratio of the fifteenth surface S15.

[0072] The non-circularity of at least one lens included in the first lens group G1 may be greater than the non-circularity of at least one lens included in the fourth lens group G4. Specifically, the eighth lens 180 of the fourth lens group G4 may have a smaller non-circularity than the first to third lenses 110, 120, and 130 of the first lens group G1.

[0073] In the optical system 1000, the third lens group G3 may include at least one lens having a non-circular shape. For example, the sixth lens 160 of the third lens group G3 may have a non-circular shape. At least one of the eleventh surface S11 and the twelfth surface S12 of the sixth lens 160 may have a non-circular shape. In particular, the effective areas of the eleventh surface S11 and the twelfth surface S12 may each have a non-circular shape.

[0074] The sixth lens 160 may have a non-circularity ratio (CH / CA) less than 1. Here, the non-circularity ratio of the sixth lens 160 may refer to the ratio (CH / CA) of the minimum effective diameter CH to the maximum effective diameter CA of the lens surface having the larger effective diameter CA between the object side surface (surface S11) and the sensor side surface (surface S12) of the sixth lens 160. In the sixth lens 160 according to the embodiment, the eleventh surface S11 may have a larger effective diameter than the twelfth surface S12. The non-circularity ratio of the sixth lens 160 may be greater than 0.7. More specifically, the non-circularity ratio of the sixth lens 160 may be greater than 0.7 and less than 1. When the non-circularity ratio of the sixth lens 160 is less than 0.7, the height of the sixth lens 160 is reduced, resulting in a slim structure. However, the area of ​​the effective area lost due to the non-circular shape is increased, resulting in reduced optical performance. Furthermore, when the non-circularity ratio of the sixth lens 160 is 1 or more, it is difficult to obtain the effect of reducing the height of the sixth lens 160 by making it a circular shape. Furthermore, the non-circularity ratio of the eleventh surface S11 of the sixth lens 160 may be smaller than the non-circularity ratio of the twelfth surface S12.

[0075] The seventh lens 170 may have a non-circular shape. At least one of the thirteenth surface S13 and the fourteenth surface S14 of the seventh lens 170 may have a non-circular shape. More specifically, the effective areas of each of the thirteenth surface S13 and the fourteenth surface S14 may have a non-circular shape. The seventh lens 170 may have a non-circularity ratio (CH / CA) less than 1. Here, the non-circularity ratio of the seventh lens 170 may refer to the ratio (CH / CA) of the minimum effective diameter CH to the maximum effective diameter CA of the lens surface having the larger effective diameter CA, either the object-side surface (thirteenth surface S13) or the sensor-side surface (fourteenth surface S14) of the seventh lens 170.

[0076] In the seventh lens 170 according to the embodiment, the fourteenth surface S14 may have a larger effective diameter than the thirteenth surface S13. The non-circularity ratio of the seventh lens 170 may be greater than 0.7. The non-circularity ratio of the seventh lens 170 may be greater than 0.7 and less than 1. If the non-circularity ratio of the seventh lens 170 is less than 0.7, the height of the seventh lens 170 is reduced, resulting in a slim structure, but the area of ​​the effective area lost due to the non-circular shape increases, degrading optical performance. If the non-circularity ratio of the seventh lens 170 is 1 or greater, the seventh lens 170 has a circular shape, making it difficult to achieve the effect of reducing the height of the seventh lens 170. Furthermore, the non-circularity ratio of the thirteenth surface S13 of the seventh lens 170 may be greater than the non-circularity ratio of the fourteenth surface S14. The non-circularity ratio of the seventh lens 170 may be different from the non-circularity ratio of the sixth lens 160. Specifically, the non-circular ratio of the sixth lens 160 may be greater than that of the seventh lens 170. For example, the non-circular ratio of the sixth lens 160 may be approximately 1.05 times or more the non-circular ratio of the seventh lens 170. Specifically, the non-circular ratio of the sixth lens 160 may be approximately 1.1 times or more the non-circular ratio of the seventh lens 170 to effectively correct chromatic aberration.

[0077] The sixth and seventh lenses 160 and 170 included in the third lens group G3 may have similar minimum effective diameters CH. Specifically, the minimum effective diameters CH of the sixth and seventh lenses 160 and 170 may correspond to each other within a range of about 5% or less, and the difference between the minimum effective diameters CH may be about 0.03 mm or less. The minimum effective diameters CH of the sixth and seventh lenses 160 and 170 included in the third lens group G3 may be smaller than the minimum effective diameters CH of the lenses 110, 120, 130, and 180 included in the first lens group G1 and the fourth lens group G4. Specifically, the maximum value of the minimum effective diameters CH of the sixth and seventh lenses 160 and 170 may be smaller than the largest value of the minimum effective diameters CH of the lenses 110, 120, 130, and 180 included in the first lens group G1 and the fourth lens group G4. The maximum value of the minimum effective diameter CH of the third lens group G3 may be about 70% to about 80% of the largest value of the minimum effective diameter CH of the lenses 110, 120, 130, and 180 included in the first lens group G1 and the fourth lens group G4.

[0078] If the maximum value of the minimum effective diameter CH of the third lens group G3 does not satisfy the above-mentioned range, it becomes difficult to structurally ensure a space between the first lens group G1 and the fourth lens group G4 for disposing the third lens group G3, and it also becomes difficult to ensure a movement distance of the third lens group G3 between the first lens group G1 and the fourth lens group G4 according to the operation mode.

[0079] In the optical system 1000, the second lens group G2 may include a lens having a circular shape. The second lens group G2 does not have to include a lens having a non-circular shape.

[0080] The fourth lens 140 may have a circular shape. More specifically, the seventh surface S7 and the eighth surface S8 of the fourth lens 140 may have a circular shape. For example, the effective areas of the seventh surface S7 and the eighth surface S8 of the fourth lens 140 may each have a circular shape. The fourth lens 140 may have a non-circularity ratio (CH / CA). Here, the non-circularity ratio of the fourth lens 140 may refer to the ratio (CH / CA) of the minimum effective diameter CH to the maximum effective diameter CA of the lens surface having the larger effective diameter CA between the object side surface (seventh surface S7) and the sensor side surface (eighth surface S8) of the fourth lens 140.

[0081] In the fourth lens 140 according to the embodiment, the seventh surface S7 may have a larger effective diameter than the eighth surface S8. The non-circularity ratio of the fourth lens 140 may be greater than 0.9 and less than 1.1. Specifically, the fourth lens 140 may be a circular lens having a circular effective area, and the non-circularity ratio may be 1. That is, the seventh surface S7 having a larger effective diameter in the fourth lens 140 may have the same maximum effective diameter CA and minimum effective diameter CH. Furthermore, the eighth surface S8 of the fourth lens 140 has a circular effective area, and may have the same non-circularity ratio as the seventh surface S7.

[0082] The fifth lens 150 may have a circular shape. More specifically, the ninth surface S9 and the tenth surface S10 of the fifth lens 150 may have a circular shape. For example, the effective areas of the ninth surface S9 and the tenth surface S10 of the fifth lens 150 may each have a circular shape. The fifth lens 150 may have a non-circularity ratio (CH / CA). Here, the non-circularity ratio of the fifth lens 150 may refer to the ratio (CH / CA) of the minimum effective diameter CH to the maximum effective diameter CA of the lens surface having the larger effective diameter CA between the object side surface (ninth surface S9) and the sensor side surface (tenth surface S10) of the fifth lens 150.

[0083] In the fifth lens 150 according to the embodiment, the ninth surface S9 may have a larger effective diameter than the tenth surface S10. The non-circularity ratio of the fifth lens 150 may be greater than 0.7. Specifically, the non-circularity ratio of the fifth lens 150 may be greater than 0.9 and less than 1.1. More specifically, the fifth lens 150 may be a circular lens having a circular effective area, and the non-circularity ratio may be 1. That is, the ninth surface S9 of the fifth lens 150 having a large effective diameter may have the same maximum effective diameter CA and minimum effective diameter CH. Furthermore, the tenth surface S10 of the fifth lens 150 may have a circular effective area and may have the same non-circularity ratio as the seventh surface S7.

[0084] The minimum effective diameter CH of the fourth and fifth lenses 140 and 150 included in the second lens group G2 may be smaller than the minimum effective diameter CH of the lenses 110, 120, 130, and 180 included in the first and fourth lens groups G1 and G4. More specifically, the maximum value of the minimum effective diameter CH of the fourth and fifth lenses 140 and 150 may be smaller than the largest value of the minimum effective diameter CH of the lenses 110, 120, 130, and 180 included in the first and fourth lens groups G1 and G4. The maximum value of the minimum effective diameter CH of the second lens group G2 may be about 70% to about 80% of the largest value of the minimum effective diameter CH of the lenses 110, 120, 130, and 180 included in the first and fourth lens groups G1 and G4.

[0085] The maximum value of the minimum effective diameter CH of the fourth and fifth lenses 140 and 150 may be similar to the maximum value of the minimum effective diameter CH of the lenses 160 and 170 included in the third lens group G3. For example, the maximum value of the minimum effective diameter CH of the lenses 140 and 150 included in the second lens group G2 may correspond to the maximum value of the minimum effective diameter CH of the lenses 160 and 170 included in the third lens group G3 within a range of about 5% or less, and the difference therebetween may be about 0.03 mm or less.

[0086] If the maximum value of the minimum effective diameter CH of the second lens group G2 does not satisfy the above-mentioned range, it becomes difficult to structurally ensure a space between the first lens group G1 and the fourth lens group G4 for disposing the second lens group G2, and it also becomes difficult to ensure a movement distance of the second lens group G2 between the first lens group G1 and the fourth lens group G4 according to the operation mode.

[0087] In the first and fourth lens groups G1 and G4, which are disposed at fixed positions even when the operation mode is changed, the non-circularity ratio (CH / CA) of the eighth lens 180 may be the smallest among the lenses 110, 120, 130, and 180 included in the first and fourth lens groups G1 and G4. Also, the non-circularity ratio (CH / CA) of the third lens 130 may be the largest among the lenses 110, 120, 130, and 180 included in the first and fourth lens groups G1 and G4. In the second and third lens groups G2 and G3, which are disposed at fixed positions even when the operation mode is changed, the non-circularity ratio (CH / CA) of the seventh lens 170 may be the smallest among the lenses 140, 150, 160, and 170 included in the second and third lens groups G2 and G3. In addition, the non-circularity ratio (CH / CA) of the fourth lens 140 and the fifth lens 150 may be the largest among the lenses 140, 150, 160, and 170 included in the lens groups G2 and G3.

[0088] As a result, the optical system 1000 according to this embodiment can have improved assembly and a mechanically stable configuration. Furthermore, the optical system 1000 can provide various magnifications by significantly reducing the movement distance of the moving lens groups. Since the effective areas of the lenses 140 and 150 included in the second lens group G2 have a circular shape, it is possible to minimize the diffraction effect that occurs in lenses with non-circular effective areas.

[0089] A camera module (not shown) according to an embodiment can include the above-described optical system 1000. The camera module can move at least one of the lens groups G1, G2, G3, and G4 included in the optical system 1000 in the direction of the optical axis OA. The camera module can include a driving member (not shown) connected to the optical system 1000. The driving member can move at least one of the lens groups in the direction of the optical axis OA depending on an operation mode.

[0090] The operation modes may include a first mode operating at a first magnification and a second mode operating at a second magnification different from the first magnification. In this case, the second magnification may be greater than the first magnification. The operation modes may also include a third mode operating at a third magnification between the first and second magnifications. Here, the first magnification may be the minimum magnification of the optical system 1000, and the second magnification may be the maximum magnification of the optical system 1000. The first magnification may be about 3 to about 5, the second magnification may be about 8 to 11, and the third magnification may be between the first and second magnifications, about 5 to about 8.

[0091] The driving member can move at least one lens group according to one operation mode selected from the first to third modes. Specifically, the driving member is connected to the second lens group G2 and the third lens group G3, and can move the second lens group G2 and the third lens group G3 according to the operation mode.

[0092] For example, in the first mode, each of the second lens group G2 and the third lens group G3 can be located at a location defined as a first position. Furthermore, in the second mode, each of the second lens group G2 and the third lens group G3 can be located at a location defined as a second position different from the first position. Furthermore, in the third mode, each of the second lens group G2 and the third lens group G3 can be located at a location defined as a third position different from the first and second positions. The third position may be a region between the first and second positions. For example, the third position at which the second lens group G2 is located in the third mode may be a region between the first and second positions at which the second lens group G2 is located in the first and second modes. Furthermore, the third position at which the third lens group G3 is located in the third mode may be a region between the first and second positions at which the third lens group G3 is located in the first and second modes.

[0093] In the optical system 1000 according to the embodiment, the second lens group G2 and the third lens group G3 are movable depending on the operation mode, and the first lens group G1 and the fourth lens group G4 are disposed at fixed positions. At the first position, the second position, and the third position depending on the operation mode, the first to fourth lens groups G1, G2, G3, and G4 may have a set interval between adjacent lens groups. As a result, the optical system 1000 may have a constant TTL (Total Track Length) even when the operation mode changes, and the effective focal length and magnification of the optical system 1000 may be controlled by controlling the positions of some lens groups.

[0094] The optical system 1000 according to the embodiment can satisfy at least one of the following formulas. As a result, the optical system 1000 according to the embodiment can effectively correct aberrations that change depending on the change in operation mode. In addition, the optical system 1000 according to the embodiment can effectively provide an autofocus (AF) function for an object at various magnifications and can have a slim and compact structure. Formula 1

[0095] n_G1, n_G2, n_G3>1 (n_G1, n_G2, n_G3 are natural numbers) In Formula 1, n_G1, n_G2, and n_G3 represent the numbers of lenses included in the first, second, and third lens groups G1, G2, and G3, respectively.

[0096] 0.7 <CH_G1max / CA_G1max<1 In Equation 2, CA_G1max represents the maximum effective diameter CA of the lens surface having the largest effective diameter among the lenses included in the first lens group G1, and CH_G1max represents the minimum effective diameter CH of the lens surface having the largest effective diameter.

[0097] 0.7 <CH_G4max / CA_G4max<1 In Equation 3, CA_G4max represents the maximum effective diameter CA of the lens surface having the largest effective diameter among the lenses included in the fourth lens group G4, and CH_G4max represents the minimum effective diameter CH of the lens surface having the largest effective diameter.

[0098] 0.7 <CH_G3max / CA_G3max<1 In Equation 4, CA_G3max represents the maximum effective diameter CA of the lens surface with the largest effective diameter among the lenses included in the third lens group G3, and CH_G3max represents the minimum effective diameter CH of the lens surface with the largest effective diameter.

[0099] CH_G4max / CA_G4max <CH_G1max / CA_G1max In Equation 5, CH_Gnmax represents the minimum effective diameter CH of the lens surface of the lens with the largest effective diameter among the lenses included in the nth lens group, and CA_Gnmax represents the maximum effective diameter CA of the lens surface of the lens with the largest effective diameter among the lenses included in the nth lens group.

[0100] 0.7<(CH_G1max / CA_G1max) / (CH_G1min / CA_G1min)<1 In Equation 6, CA_G1max represents the maximum effective diameter CA of the lens surface of the lens with the largest effective diameter among the lenses included in the first lens group G1, and CH_G1max represents the minimum effective diameter CH of the lens surface of the lens with the largest effective diameter. CA_G1min represents the maximum effective diameter CA of the lens surface of the lens with the smallest effective diameter among the lenses included in the first lens group G1, and CH_G1min represents the minimum effective diameter CH of the lens surface of the lens with the smallest effective diameter.

[0101] CH_G2max / CA_G2max=CH_G2min / CA_G2min In Equation 7, CA_G2max means the maximum effective diameter CA of the lens surface of the lens with the largest effective diameter among the lenses included in the second lens group G2, and CH_G2max means the minimum effective diameter CH of the lens surface of the lens with the largest effective diameter. CA_G2min means the maximum effective diameter CA of the lens surface of the lens with the smallest effective diameter among the lenses included in the second lens group G2, and CH_G2min means the minimum effective diameter CH of the lens surface of the lens with the smallest effective diameter.

[0102] 0.9 <CH_G1max / CH_G4max<1.1 In Equation 8, CH_G1max represents the minimum effective diameter CH of the lens surface of the lens with the largest effective diameter among the lenses included in the first lens group G1, and CH_G4max represents the minimum effective diameter CH of the lens surface of the lens with the largest effective diameter among the lenses included in the fourth lens group G4.

[0103] 1 <CH_G1max / CH_G2max<2 In Equation 9, CH_G1max represents the minimum effective diameter CH of the lens surface of the lens with the largest effective diameter among the lenses included in the first lens group G1, and CA_G2max represents the minimum effective diameter CH of the lens surface of the lens with the largest effective diameter among the lenses included in the second lens group G2.

[0104] 1 <CH_G4max / CH_G3max<2 In Equation 10, CH_G3max represents the minimum effective diameter CH of the lens surface of the lens with the largest effective diameter among the lenses included in the third lens group G3, and CH_G4max represents the minimum effective diameter CA of the lens surface of the lens with the largest effective diameter among the lenses included in the fourth lens group G4.

[0105] 0.9 <CH_G2max / CH_G3max<1.1 In Equation 11, CH_G2max represents the minimum effective diameter CA of the lens surface having the largest effective diameter among the lenses included in the second lens group G2, and CH_G3max represents the minimum effective diameter CH of the lens surface having the largest effective diameter among the lenses included in the third lens group G3.

[0106] CH_G4max / CH_G1max <CA_G4max / CA_G1max In Equation 12, CH_Gnmax represents the minimum effective diameter CH of the lens surface of the lens with the largest effective diameter among the lenses included in the nth lens group, and CA_Gnmax represents the maximum effective diameter CA of the lens surface of the lens with the largest effective diameter among the lenses included in the nth lens group.

[0107] When the optical system 1000 according to the embodiment satisfies at least one or more of Formulas 1 to 12, the optical system 1000 can have a slim structure. Specifically, the optical system 1000 is provided slim by reducing the height while minimizing the area of ​​the effective area lost due to a non-circular shape. The optical system 1000 can prevent a decrease in optical performance due to a reduction in the area of ​​the effective area caused by a non-circular lens, control aberration characteristics, and minimize the diffraction effect generated by a non-circular lens. In addition, the optical system 1000 can have improved assembly properties and a mechanically stable form. Formula 13

[0108] 1 <L_G1 / L_G2<3 In Equation 13, L_G1 refers to the distance, along the optical axis OA, between the object-side surface of the lens closest to the object among the lenses included in the first lens group G1 and the sensor-side surface of the lens closest to the image sensor 300. For example, L_G1 refers to the distance, along the optical axis OA, between the first surface S1 of the first lens 110 and the sixth surface S6 of the third lens 130. L_G2 refers to the distance, along the optical axis OA, between the object-side surface of the lens closest to the object among the lenses included in the second lens group G2 and the sensor-side surface of the lens closest to the image sensor 300. For example, L_G2 refers to the distance, along the optical axis OA, between the seventh surface S7 of the fourth lens 140 and the tenth surface S10 of the fifth lens 150.

[0109] 1 <L_G1 / L_G3<3 In Equation 14, L_G1 refers to the distance, along the optical axis OA, between the object-side surface of the lens closest to the object among the lenses included in the first lens group G1 and the sensor-side surface of the lens closest to the image sensor 300. For example, L_G1 refers to the distance, along the optical axis OA, between the first surface S1 of the first lens 110 and the sixth surface S6 of the third lens 130. L_G3 refers to the distance, along the optical axis OA, between the object-side surface of the lens closest to the object among the lenses included in the third lens group G3 and the sensor-side surface of the lens closest to the image sensor 300. For example, L_G3 refers to the distance, along the optical axis OA, between the eleventh surface S11 of the sixth lens 160 and the fourteenth surface S14 of the seventh lens 170.

[0110] When the optical system 1000 according to the embodiment satisfies at least one of Equation 13 and Equation 14, it has a relatively small TTL and can provide various magnifications according to mode changes.

[0111] 0.05 <L_G1 / TTL<0.5 In Equation 15, L_G1 refers to the distance on the optical axis OA between the object side surface of the lens closest to the object among the lenses included in the first lens group G1 and the sensor side surface of the lens closest to the image sensor 300. For example, L_G1 refers to the distance on the optical axis OA between the first surface S1 of the first lens 110 and the sixth surface S6 of the third lens 130. TTL (Total Track Length) refers to the distance (mm) on the optical axis OA from the object side surface (first surface S1) of the first lens 110 to the top surface of the image sensor 300. When the optical system 1000 according to the embodiment satisfies Equation 15, the optical system 1000 has a relatively small TTL and can control stray light incident on the first lens group G1, thereby providing improved optical characteristics. Equation 16

[0112] 0.05 <L_G2 / TTL<0.5 In Equation 16, L_G2 represents the distance on the optical axis OA between the object side surface of the lens closest to the object among the lenses included in the second lens group G2 and the sensor side surface of the lens closest to the image sensor 300. For example, L_G2 represents the distance on the optical axis OA between the seventh surface S7 of the fourth lens 140 and the tenth surface S10 of the fifth lens 150.

[0113] When the optical system 1000 according to the embodiment satisfies Equation 16, the optical system 1000 has a relatively small TTL, and the diffraction effect occurring in the non-circular lens can be minimized, thereby improving the chromatic aberration characteristics.

[0114] 20<|vd4-vd5| In Equation 17, vd4 represents the Abbe's number of the fourth lens 140, and vd5 represents the Abbe's number of the fifth lens 150.

[0115] When the optical system 1000 according to the embodiment satisfies the formula 17, the optical system 1000 can improve the chromatic aberration characteristics.

[0116] 20<|vd6-vd7| In Equation 18, vd6 represents the Abbe number of the sixth lens, and vd7 represents the Abbe number of the seventh lens.

[0117] When the optical system 1000 according to the embodiment satisfies Expression 18, the optical system 1000 can improve the chromatic aberration characteristics.

[0118] 1.6 <n3d In Equation 19, n3d represents the refractive index of the third lens 130.

[0119] When the optical system 1000 according to the embodiment satisfies Equation 19, the effective area of ​​the lenses disposed after the third lens 130 can be secured, and the height of the lenses can be reduced.

[0120] 1 <L1R1 / L3R2<2 In Equation 20, L1R1 represents the radius of curvature of the object side surface (first surface S1) of the first lens 110, and L3R2 represents the radius of curvature of the sensor side surface (sixth surface S6) of the third lens 130.

[0121] When the optical system 1000 according to the embodiment satisfies Equation 20, the optical system 1000 can control stray light incident on the first lens group G1.

[0122] 1 <L1R1 / L4R1<2 In Equation 21, L1R1 represents the radius of curvature of the object side surface (first surface S1) of the first lens 110, and L4R1 represents the radius of curvature of the object side surface (seventh surface S7) of the fourth lens 140.

[0123] When the optical system 1000 according to the embodiment satisfies Equation 21, the optical system 1000 can have good optical performance at various magnifications.

[0124] 1 <L3R2 / L4R1<2 In Equation 22, L3R2 represents the radius of curvature of the sensor side surface (sixth surface S6) of the third lens 130, and L4R1 represents the radius of curvature of the object side surface (seventh surface S7) of the fourth lens 140.

[0125] When the optical system 1000 according to the embodiment satisfies Equation 22, the optical system 1000 can have good optical performance at various magnifications in the peripheral part of the field of view (FOV) during operation.

[0126] -1.5 <L1R1 / L8R2<0 In Equation 23, L1R1 represents the radius of curvature of the object side surface (first surface S1) of the first lens 110, and L8R2 represents the radius of curvature of the sensor side surface (sixteenth surface S16) of the eighth lens 180.

[0127] When the optical system 1000 according to the embodiment satisfies Equation 23, the optical system 1000 can have good optical performance in the center and periphery of the field of view (FOV).

[0128] 0.05 <m_G2 / TTL<0.5 In Equation 24, m_G2 represents the movement distance of the second lens group G2 when changing from the first mode operating at a first magnification to the second mode operating at a second magnification, or from the second mode to the first mode. Specifically, m_G2 represents a value relative to the difference between the distance on the optical axis OA between the first and second lens groups G1 and G2 in the first mode and the distance on the optical axis OA between the first and second lens groups G1 and G2 in the second mode.

[0129] When the optical system 1000 according to the embodiment satisfies Expression 24, the optical system 1000 can minimize the movement distance of the second lens group G2 when changing the magnification, and the optical system 1000 can have a slim structure. Furthermore, the movement distance when controlling the position of the second lens group G2 can be minimized, and the optical system 1000 can have improved power consumption characteristics. Expression 25

[0130] 0.05 <m_G3 / TTL<0.5 In Equation 25, m_G3 represents the movement distance of the third lens group G3 when changing from the first mode operating at a first magnification to the second mode operating at a second magnification, or from the second mode to the first mode. Specifically, m_G3 represents the difference between the distance along the optical axis OA between the third and fourth lens groups G3 and G4 in the first mode and the distance along the optical axis OA between the third and fourth lens groups G3 and G4 in the second mode. When the optical system 1000 according to the embodiment satisfies Equation 25, the optical system 1000 can minimize the movement distance of the third lens group G3 when changing magnification, and can have a slim structure. Furthermore, the movement distance can be minimized when controlling the position of the third lens group G3, and can have improved power consumption characteristics. Equation 26

[0131] 1.5 <m_G2 / L_G2<2.5 In Equation 26, m_G2 represents the movement distance of the second lens group G2 when switching from the first mode operating at a first magnification to the second mode operating at a second magnification, or from the second mode to the first mode. Specifically, m_G2 represents the difference between the distance along the optical axis OA between the first and second lens groups G1 and G2 in the first mode and the distance along the optical axis OA between the first and second lens groups G1 and G2 in the second mode. L_G2 represents the distance along the optical axis OA between the object-side surface of the lens closest to the object among the lenses included in the second lens group G2 and the sensor-side surface of the lens closest to the image sensor 300. For example, L_G2 represents the distance along the optical axis OA between the seventh surface S7 of the fourth lens 140 and the tenth surface S10 of the fifth lens 150.

[0132] When the optical system 1000 according to the embodiment satisfies Expression 26, the optical system 1000 can minimize the movement distance of the second lens group G2 when changing the magnification, and the optical system 1000 can have a slim structure. Furthermore, the movement distance when controlling the position of the second lens group G2 can be minimized, and the optical system 1000 can have improved power consumption characteristics. Expression 27

[0133] 2 <m_G3 / L_G3<3.5 In Equation 27, m_G3 represents the movement distance of the third lens group G3 when switching from the first mode operating at a first magnification to the second mode operating at a second magnification, or from the second mode to the first mode. Specifically, m_G3 represents the difference between the distance along the optical axis OA between the third and fourth lens groups G3 and G4 in the first mode and the distance along the optical axis OA between the third and fourth lens groups G3 and G4 in the second mode. L_G3 represents the distance along the optical axis OA between the object-side surface of the lens closest to the object among the lenses included in the third lens group G3 and the sensor-side surface of the lens closest to the image sensor 300. For example, L_G3 represents the distance along the optical axis OA between the eleventh surface S11 of the sixth lens 160 and the fourteenth surface S14 of the seventh lens 170.

[0134] When the optical system 1000 according to the embodiment satisfies Expression 27, the optical system 1000 can minimize the movement distance of the third lens group G3 when changing the magnification, and the optical system 1000 can have a slim structure. Furthermore, the movement distance when controlling the position of the third lens group G3 can be minimized, and the optical system 1000 can have improved power consumption characteristics. Expression 28

[0135] 4 <d_G12_mode1 / d_G34_mode1<12 In Equation 28, d_G12_mode1 refers to the distance between the first lens group G1 and the second lens group G2 in the first mode in which the second lens group G2 and the third lens group G3 are disposed at first positions. That is, d_G12_mode1 refers to the distance between the third lens 130 and the fourth lens 140 on the optical axis OA in the first mode. d_G34_mode1 refers to the distance between the third lens group G3 and the fourth lens group G4 in the first mode in which the second lens group G2 and the third lens group G3 are disposed at first positions. That is, d_G34_mode1 refers to the distance between the seventh lens 170 and the eighth lens 180 on the optical axis OA in the first mode.

[0136] When the optical system 1000 according to the embodiment satisfies Expression 28, the optical system 1000 can have improved optical characteristics at a first magnification. Specifically, the optical system 1000 can have improved aberration characteristics at the first magnification, and can improve optical performance at the center and periphery of the field of view (FOV). Expression 29

[0137] 0.01 <d_G12_mode2 / d_G34_mode2<0.5 In Equation 29, d_G12_mode2 refers to the distance between the first lens group G1 and the second lens group G2 in the second mode in which the second lens group G2 and the third lens group G3 are disposed at the second position. That is, d_G12_mode2 refers to the distance between the third lens 130 and the fourth lens 140 on the optical axis OA in the second mode. d_G34_mode2 refers to the distance between the third lens group G3 and the fourth lens group G4 in the second mode in which the second lens group G2 and the third lens group G3 are disposed at the second position. That is, d_G34_mode2 refers to the distance between the seventh lens 170 and the eighth lens 180 on the optical axis OA in the second mode.

[0138] When the optical system 1000 according to the embodiment satisfies Expression 29, the optical system 1000 can have improved optical characteristics at the second magnification. Specifically, the optical system 1000 has improved aberration characteristics at the second magnification, and can improve optical performance at the periphery of the field of view (FOV). Expression 30

[0139] 0.1 <EFL_1 / EFL_2<1 In Equation 30, EFL_1 is a first effective focal length, which is the effective focal length (EFL) of the optical system 1000 when operating in the first mode with the second lens group G2 and the third lens group G3 located at a first position. EFL_2 is a second effective focal length, which is the effective focal length (EFL) of the optical system 1000 when operating in the second mode with the second lens group G2 and the third lens group G3 located at a second position.

[0140] 2 <EFL_1 / EPD_1<3 In Equation 31, EFL_1 is a first effective focal length, which is the effective focal length (EFL) of the optical system 1000 when the second lens group G2 and the third lens group G3 are positioned at first positions and the optical system 1000 operates in the first mode. EPD_1 is an entrance pupil diameter (EPD) of the optical system 1000 when the second lens group G2 and the third lens group G3 are positioned at first positions and the optical system 1000 operates in the first mode.

[0141] When the optical system 1000 according to the embodiment satisfies Equation 31, the optical system 1000 can ensure a bright image when operating in the first mode.

[0142] 4.5 <EFL_2 / EPD_2<6 In Equation 32, EFL_2 is a second effective focal length, which is the effective focal length (EFL) of the optical system 1000 when the second lens group G2 and the third lens group G3 are positioned at the second position and the optical system 1000 operates in the second mode. EPD_2 is the entrance pupil diameter (EPD) of the optical system 1000 when the second lens group G2 and the third lens group G3 are positioned at the second position and the optical system 1000 operates in the second mode.

[0143] When the optical system 1000 according to the embodiment satisfies Equation 32, the optical system 1000 can ensure a bright image when operating in the second mode.

[0144] F#_Mode1<3.5F#_Mode2<6.0 In Equation 33, F#_mode1 represents the F-number of the optical system 1000 when operating in the first mode in which the second lens group G2 and the third lens group G3 are located at a first position, and F#_mode2 represents the F-number of the optical system 1000 when operating in the second mode in which the second lens group G2 and the third lens group G3 are located at a second position.

[0145] 1 <TTL / EFL_1<3 In Equation 34, EFL_1 is a first effective focal length, which is the effective focal length (EFL) of the optical system 1000 when operating in the first mode in which the second lens group G2 and the third lens group G3 are located at a first position. The relationship between TTL and EFL_1 can be set using Equation 34.

[0146] 0.1 <TTL / EFL_2<1 In Equation 35, EFL_2 is a second effective focal length, which is the effective focal length (EFL) of the optical system 1000 when operating in the second mode in which the second lens group G2 and the third lens group G3 are located at the second position. The relationship between TTL and EFL_2 can be set using Equation 35.

[0147] 1 <CA_Smax / ImgH<4 In Equation 36, CA_Smax represents the largest effective diameter CA of the lens surfaces of the lenses 100 included in the optical system 1000. ImgH represents the distance from the 0 field area at the center of the top surface of the image sensor 300, which overlaps with the optical axis OA, to the 1.0 field area of ​​the image sensor 300, and this distance is the distance in the perpendicular direction to the optical axis OA. That is, ImgH represents 1 / 2 of the entire diagonal length of the effective area of ​​the image sensor 300.

[0148] When the optical system 1000 according to the embodiment satisfies Equation 36, the optical system 1000 can be slim and compact. In addition, the optical system 1000 can achieve high resolution and high image quality.

[0149] 5 <TTL / ImgH<10 In Equation 37, TTL (Total track length) refers to the distance (mm) on the optical axis OA from the object side surface (first surface S1) of the first lens 110 to the top surface of the image sensor 300. ImgH refers to the distance from the 0 field area at the center of the top surface of the image sensor 300, which overlaps with the optical axis OA, to the 1.0 field area of ​​the image sensor 300, and this distance is the distance in the vertical direction of the optical axis OA. That is, ImgH refers to 1 / 2 of the entire diagonal length of the effective area of ​​the image sensor 300.

[0150] When the optical system 1000 according to the embodiment satisfies Equation 37, the optical system 1000 can have a smaller TTL, and the optical system 1000 can be provided in a slim and compact form.

[0151] 15 <TTL / BFL<30 In Equation 38, TTL (Total track length) means the distance (mm) on the optical axis OA from the object side (first surface S1) of the first lens 110 to the top surface of the image sensor 300. BFL (Back focal length) means the distance on the optical axis OA from the apex of the sensor side of the lens closest to the image sensor 300 to the top surface of the image sensor 300.

[0152] 2 <ImgH / BFL<4 In Equation 38, ImgH is the distance from the 0 field area at the center of the top surface of the image sensor 300, which overlaps with the optical axis OA, to the 1.0 field area of ​​the image sensor 300, and this distance is the vertical distance of the optical axis OA. That is, ImgH means 1 / 2 of the entire diagonal length of the effective area of ​​the image sensor 300. BFL (Back focal length) means the distance on the optical axis OA from the apex of the sensor side of the lens closest to the image sensor 300 to the top surface of the image sensor 300.

[0153] When the optical system 1000 according to the embodiment satisfies Equation 39, it is possible to ensure the BFL required for a relatively large image sensor 300, for example, a large image sensor of about 1 inch.

[0154] In addition, when the optical system 1000 satisfies Equation 39, the optical system 1000 can operate at various magnifications while maintaining TTL, and can have excellent optical characteristics at the center and periphery of the field of view (FOV).

[0155] TIFF0007827754000001.tif22168In Equation 40, Z, as Sag, may represent the distance in the optical axis direction from an arbitrary position on the aspheric surface to the apex of the aspheric surface. Y may represent the distance in the direction perpendicular to the optical axis from an arbitrary position on the aspheric surface to the optical axis. c may represent the curvature of the lens, and K may represent the Conic constant. A, B, C, D, E, and F may represent aspheric constants.

[0156] The optical system 1000 according to the embodiment can satisfy at least one or more of the above-described formulas 1 to 39. As a result, the optical system 1000 and the camera module can have improved optical characteristics. Specifically, by satisfying at least one or more of the formulas 1 to 39, the optical system 1000 can effectively correct degradation of optical characteristics, such as chromatic aberration, vignetting, diffraction effect, and degradation of image quality in peripheral areas, which occur due to movement of the lens groups. Furthermore, the optical system 1000 according to the embodiment can provide an autofocus (AF) function for various magnifications by significantly reducing the movement distance of the lens groups and having excellent power consumption characteristics.

[0157] By satisfying at least one or more of the above formulas 1 to 39, the optical system 1000 according to the embodiment can have improved assembly properties, a mechanically stable form, and a slim structure, so that the optical system 1000 and a camera module including the same can have a compact structure.

[0158] The optical system 1000 according to the embodiment and the first to third mode changes will be described in more detail below.

[0159] In the optical system 1000 according to the embodiment, the first lens group G1 and the fourth lens group G4 are fixed, and the second lens group G2 and the third lens group G3 are movable. The first lens group G1 may include three lenses, e.g., the first to third lenses 110, 120, and 130, and the second lens group G2 may include two lenses, e.g., the fourth and fifth lenses 140 and 150. The third lens group G3 may include two lenses, e.g., the sixth and seventh lenses 160 and 170, and the fourth lens group G4 may include one lens, e.g., the eighth lens 180. In the optical system 1000 according to the embodiment, the object-side surface (seventh surface S7) of the fourth lens 140 may function as an aperture, and the above-mentioned filter 500 is disposed between the fourth lens group G4 and the image sensor 300. [Table 1] [Table 2] [Table 3]

[0160] Tables 1 to 3 show lens data for the optical system 1000 according to the embodiment and the camera module including the same when the optical system 1000 operates in the first mode. Specifically, Tables 1 and 2 show the radius of curvature, center thickness, distance between centers of the lenses, refractive index, Abbe's number, and maximum and minimum effective diameters (CA, CH) of the first to eighth lenses 110, 120, 130, 140, 150, 160, 170, and 180. Table 3 shows the effective focal length EFL_1 and entrance pupil size EPD_1 for the first mode having the first magnification, the distance d_G12 between the first lens group G1 and the second lens group G2, the distance d_G23 between the second lens group G2 and the third lens group G3, and the distance d_G34 between the third lens group G3 and the fourth lens group G4. Referring to Table 1, the first lens 110 on the optical axis OA of the optical system 1000 according to the embodiment may have a positive (+) refractive power. The first lens 110 may include a plastic material. On the optical axis OA, the first surface S1 of the first lens 110 may have a convex shape, and the second surface S2 may have a concave shape. The first lens 110 may have a meniscus shape that bulges toward the object side on the optical axis OA. The first surface S1 may be an aspheric surface, and the second surface S2 may be an aspheric surface.

[0161] The second lens 120 may have a positive (+) refractive power on the optical axis OA. The second lens 120 may include a plastic material. On the optical axis OA, the third surface S3 of the second lens 120 may have a convex shape, and the fourth surface S4 may have a concave shape. The second lens 120 may have a meniscus shape that bulges toward the object side on the optical axis OA. The third surface S3 may be an aspheric surface, and the fourth surface S4 may be an aspheric surface.

[0162] The third lens 130 may have a refractive power opposite to that of the first lens 110 along the optical axis OA. Specifically, the third lens 130 may have a negative (-) refractive power along the optical axis OA. The third lens 130 may include a glass material. A fifth surface S5 of the third lens 130 may have a concave shape along the optical axis OA, and a sixth surface S6 of the third lens 130 may have a concave shape along the optical axis OA. The third lens 130 may have a concave shape on both sides along the optical axis. The fifth surface S5 may be aspherical, and the sixth surface S6 may be aspherical. The third lens 130 may have a refractive index greater than about 1.6. The third lens 130 may have the highest refractive index of the lenses included in the first lens group G1. For example, the third lens 130 may have the highest refractive index of the plurality of lenses 100. Specifically, the refractive index of the third lens 130 may be greater than 1.8.

[0163] The fourth lens 140 may have a positive (+) refractive power on the optical axis OA. The fourth lens 140 may include a plastic material. On the optical axis OA, the seventh surface S7 of the fourth lens 140 may have a convex shape, and the eighth surface S8 may have a convex shape. The fourth lens 140 may have a biconvex shape. The seventh surface S7 may be an aspheric surface, and the eighth surface S8 may be an aspheric surface.

[0164] The fifth lens 150 may have a refractive power opposite to that of the fourth lens 140 along the optical axis OA. Specifically, the fifth lens 150 may have a negative (-) refractive power along the optical axis OA. The fifth lens 150 may include a plastic material. A ninth surface S9 of the fifth lens 150 may have a convex shape, and a tenth surface S10 of the fifth lens 150 may have a concave shape along the optical axis OA. The fifth lens 150 may have a meniscus shape that bulges toward the object side along the optical axis OA. The ninth surface S9 may be an aspheric surface, and the tenth surface S10 may be an aspheric surface. The sixth lens 160 may have a positive (+) refractive power along the optical axis OA. The sixth lens 160 may include a plastic material. An eleventh surface S11 of the sixth lens 160 may have a concave shape, and a twelfth surface S12 of the sixth lens 160 may have a convex shape along the optical axis OA. The sixth lens 160 may have a meniscus shape that bulges toward the sensor on the optical axis OA. The eleventh surface S11 may be an aspheric surface, and the twelfth surface S12 may be an aspheric surface.

[0165] The seventh lens 170 may have a refractive power opposite to that of the sixth lens 160 on the optical axis OA. Specifically, the seventh lens 170 may have a negative (-) refractive power on the optical axis OA. The seventh lens 170 may include a glass material. On the optical axis OA, a thirteenth surface S13 of the seventh lens 170 may have a concave shape, and a fourteenth surface S14 may have a concave shape. The seventh lens 170 may have a concave shape on both sides on the optical axis OA. The thirteenth surface S13 may be an aspherical surface, and the fourteenth surface S14 may be an aspherical surface. The eighth lens 180 may have a positive (+) refractive power on the optical axis OA. The eighth lens 180 may include a plastic material. On the optical axis OA, a fifteenth surface S15 of the eighth lens 180 may have a convex shape, and a sixteenth surface S16 may have a convex shape. The eighth lens 180 may have a biconvex shape on the optical axis OA. The fifteenth surface S15 may be an aspheric surface, and the sixteenth surface S16 may be an aspheric surface.

[0166] In addition, the values ​​of the aspherical coefficients of the lens surfaces in the optical system 1000 according to the example are as shown in Table 4 below. [Table 4]

[0167] In the optical system 1000 according to the embodiment, the lenses 100 may have a non-circularity ratio as shown in Table 5 below. Here, the non-circularity ratio may refer to the ratio (CH / CA) of the minimum clear height (CH) to the maximum clear height (CA) of the lens surface with the larger clear aperture (CA) on the object side or the sensor side of the lens. [Table 5]

[0168] Referring to Table 5, the non-circularity ratios of the lenses 100 may be different from one another. Specifically, in the first lens group G1, the first lens 110 may have the smallest non-circularity ratio, and the third lens 130 may have the largest non-circularity ratio. The third lens 130 may be a circular lens with a circular effective area, and the non-circularity ratio may be 1. The non-circularity ratio of the lenses included in the first lens group G1 may be greater as the lens is closer to the second lens group G2, i.e., a moving group whose position changes depending on the operating mode. The non-circularity ratios of the fourth lens 140 and the fifth lens 150 in the second lens group G2 may be the same. Specifically, the fourth lens 140 and the fifth lens 150 may be circular lenses with circular effective areas. Thus, the non-circularity ratios of the fourth lens 140 and the fifth lens 150 may be the same, i.e., 1.

[0169] In the third lens group G3, the sixth lens 160 may have a larger non-circularity than the seventh lens 170. The non-circularity of the lenses included in the third lens group G3 may be a moving group whose position changes depending on the operation mode, i.e., a lens adjacent to the second lens group G2, and the non-circularity of the lenses included in the third lens group G3 may be a fixed group whose position is fixed, i.e., a lens adjacent to the fourth lens group G4, and the non-circularity of the lenses included in the third lens group G3 may be a fixed group whose position is fixed ...

[0170] Among the lenses included in the moving groups G2 and G3, the fourth lens 140 and the fifth lens 150 may have the largest non-circularity ratio, and the seventh lens 170 may have the smallest non-circularity ratio. Among the lenses included in the fixed groups G1 and G4, the third lens 130 may have the largest non-circularity ratio, and the eighth lens 180 may have the smallest non-circularity ratio. In this case, the eighth lens 180 may have the smallest non-circularity ratio among the plurality of lenses 100. That is, the non-circularity ratios of the non-circular lenses among the plurality of lenses 100 may be greatest in the order of the second lens 120, the sixth lens 160, the first lens 110, the seventh lens 170, and the eighth lens 180.

[0171] The Abbe number vd4 of the fourth lens 140 included in the second lens group G2 may differ from the Abbe number vd5 of the fifth lens 150 by 20 or more. Because the fourth lens 140 and the fifth lens 150 have the above-described difference in Abbe number, it is possible to minimize a change in chromatic aberration that occurs when the magnification changes due to the movement of the second lens group G2. The Abbe number vd7 of the seventh lens 170 included in the third lens group G3 may differ from the Abbe number vd6 of the sixth lens 160 by 20 or more. Because the sixth lens 160 and the seventh lens 170 have the above-described difference in Abbe number, it is possible to minimize and / or compensate for a change in chromatic aberration that occurs when the magnification changes due to the movement of the third lens group G3, and to function as an achromat.

[0172] The camera module according to the embodiment can acquire information about a subject at various magnifications. Specifically, the driving member can control the positions of the second lens group G2 and the third lens group G3, thereby allowing the camera module to operate at various magnifications. For example, referring to FIGS. 1 to 4 and Tables 1 to 5, the camera module including the optical system 1000 can operate in the first mode having a first magnification. The first magnification may be approximately 3 to 5. Specifically, in the embodiment, the first magnification may be approximately 4.4. In the first mode, the second lens group G2 and the third lens group G3 can be positioned at a location defined as a first position. When the initial positions of the second lens group G2 and the third lens group G3 are the first positions, the lens groups G2 and G3 do not need to move. Alternatively, when the initial positions of the second lens group G2 and the third lens group G3 are different from the first positions, the lens groups G2 and G3 can be moved to the first positions by the driving force of the driving member.

[0173] As a result, the first to fourth lens groups G4 are disposed at predetermined intervals. For example, the second lens group G2 may be located in an area separated from the first lens group G1 by a first distance d_G12, the third lens group G3 by a second distance d_G34, and the second lens group G2 by a third distance d_G23 from the third lens group G3. Here, the first to third distances d_G12, d_G34, and d_G23 may refer to the distances between the lens groups on the optical axis OA.

[0174] When the camera module operates in the first mode, the optical system 1000 may have a first TTL (TTL_1) that defines a TTL (total track length) value at the first position, a first BFL (BFL_1) that defines a BFL (back focal length) value, a first EFL (EFL_1) that defines a first effective focal length at the first position, a field of view (FOV) of the camera module in the first mode may be less than about 25 degrees, and an F-number may be less than about 3.5.

[0175] The optical system 1000 can have excellent aberration characteristics in the first mode as shown in Figures 3 and 4. More specifically, Figure 3 is a graph of the diffraction MTF characteristics of the optical system 1000 operating in the first mode (first magnification), and Figure 4 is a graph of the aberration characteristics.

[0176] 4 shows a graph of spherical aberration, astigmatic field curves, and distortion measured from left to right in the aberration graph of FIG. 4. In FIG. 4, the X-axis represents focal length (mm) and distortion (%), and the Y-axis represents image height. The spherical aberration graph is for light in wavelength bands of approximately 435 nm, 486 nm, 546 nm, 587 nm, and 656 nm, while the astigmatic field curves are for light in the 546 nm wavelength band. In FIG. 4, the closer the aberration curves are to the Y-axis, the better the aberration correction function. Referring to FIG. 4, it can be seen that the measured values ​​for the optical system 1000 according to the embodiment are adjacent to the Y-axis in almost all areas. [Table 6]

[0177] Table 6 relates to the effective focal length EFL_2 and the entrance pupil size EPD_2 for the second mode having the second magnification, the distance d_G12 between the first lens group G1 and the second lens group G2, the distance d_G23 between the second lens group G2 and the third lens group G3, and the distance d_G34 between the third lens group G3 and the fourth lens group G4. The camera module according to the embodiment can acquire information about a subject at various magnifications. Specifically, the driving member can control the positions of the second lens group G2 and the third lens group G3, thereby allowing the camera module to operate at various magnifications. For example, referring to FIGS. 5 to 7 and Tables 1 and 6, a camera module including the optical system 1000 can operate in the second mode having a second magnification. The second magnification may be approximately 8 magnifications to approximately 11 magnifications. Specifically, the second magnification may be approximately 9.6 magnifications. In the second mode, the second lens group G2 and the third lens group G3 can each be positioned at a location defined as a second position. When the initial positions of the second lens group G2 and the third lens group G3 are the second positions, the lens groups G2 and G3 do not need to move. Alternatively, when the initial positions of the second lens group G2 and the third lens group G3 are different from the second positions, the lens groups G2 and G3 can be moved to the second positions by the driving force of the driving member.

[0178] As a result, the first to fourth lens groups G4 are disposed at predetermined intervals. For example, the second lens group G2 may be located in an area separated from the first lens group G1 by a first distance d_G12, the third lens group G3 by a second distance d_G34, and the second lens group G2 by a third distance d_G23 from the third lens group G3. Here, the first to third distances d_G12, d_G34, and d_G23 may refer to the distances between the lens groups on the optical axis OA.

[0179] The first distance d_G12 in the first mode may be larger than the first distance d_G12 in the second mode, and the second distance d_G34 in the first mode may be smaller than the second distance d_G34 in the second mode. The third distance d_G23 in the first mode may be larger than the third distance d_G23 in the second mode. When the camera module operates in the second mode, the optical system 1000 may have a second TTL (TTL_2) defined as a TTL (Total Track Length) value at the second position and a second BFL (BFL_2) defined as a BFL (Back Focal Length) value. The optical system 1000 may also have a second EFL (EFL_2) defined as a second effective focal length at the second position. The second EFL (EFL_2) may be larger than the first EFL (EFL_1). Additionally, the field of view (FOV) of the camera module in the second mode may have an F-number less than about 12 degrees and less than about 6.5.

[0180] The optical system 1000 may have excellent aberration characteristics in the second mode, as shown in FIGS. 6 and 7. Specifically, FIG. 6 is a graph showing the diffraction MTF characteristics of the optical system 1000 operating in the second mode (second magnification), and FIG. 7 is a graph showing the aberration characteristics. The aberration graph in FIG. 7 shows the longitudinal spherical aberration, astigmatic field curves, and distortion measured from left to right. In FIG. 7, the X axis represents focal length (mm) and distortion (%), and the Y axis represents image height. The spherical aberration graph is for light in wavelength bands of approximately 435 nm, 486 nm, 546 nm, 587 nm, and 656 nm, while the astigmatic and distortion graphs are for light in the 546 nm wavelength band. In the aberration degree of Figure 7, it can be interpreted that the closer each curve is to the Y-axis, the better the aberration correction function. Referring to Figure 7, it can be seen that the measured values ​​of the optical system 1000 according to the embodiment are adjacent to the Y-axis in almost the majority of the area. [Table 7]

[0181] Table 7 relates to the effective focal length EFL_3 and the entrance pupil size EPD_3 for the third mode having the third magnification, the distance between the first lens group G1 and the second lens group G2, the distance between the second lens group G2 and the third lens group G3, and the distance between the third lens group G3 and the fourth lens group G4. The camera module according to the embodiment can acquire information about a subject at various magnifications. Specifically, the driving member can control the positions of the second lens group G2 and the third lens group G3, thereby allowing the camera module to operate at various magnifications. For example, referring to FIGS. 8 to 10 and Tables 1 and 7, a camera module including the optical system 1000 can operate in the third mode having a third magnification. The third magnification may be approximately 5 to 8 magnifications. Specifically, the third magnification may be approximately 7 magnifications. In the third mode, the second lens group G2 and the third lens group G3 can each be positioned at a location defined as a third position. The third position may be a region between the first and second positions. For example, the third position of the second lens group G2 may be located between the first and second positions of the second lens group G2, and the third position of the third lens group G3 may be located between the first and second positions of the third lens group G3. When the initial positions of the second lens group G2 and the third lens group G3 are the third positions, the lens groups G2 and G3 do not need to move. Alternatively, when the initial positions of the second lens group G2 and the third lens group G3 are different from the third positions, the lens groups G2 and G3 may be moved to the third positions by the driving force of the driving member.

[0182] As a result, the first to fourth lens groups G4 are disposed at predetermined intervals. For example, the second lens group G2 may be located in an area separated from the first lens group G1 by a first interval d_G12, the third lens group G3 by a second interval d_G34, and the second lens group G2 by a third interval d_G23. Here, the first to third intervals d_G12, d_G34, and d_G23 may refer to the intervals between the lens groups on the optical axis OA. The first interval d_G12 of the third mode may be smaller than the first interval d_G12 of the first mode and may be larger than the first interval d_G12 of the second mode. The second interval of the third mode may be larger than the second interval d_G34 of the first mode and may be smaller than the second interval d_G34 of the second mode. The third distance d_G23 of the third mode may be smaller than the third distance d_G23 of the first mode and the third distance d_G23 of the second mode.

[0183] When the camera module operates in the third mode, the optical system 1000 may have a third TTL (TTL_3) defined as a total track length (TTL) value at the third position and a third BFL (BFL_3) defined as a back focal length (BFL) value. The optical system 1000 may also have a third effective focal length (EFL_3) defined as a third effective focal length (EFL_2) at the third position. The third EFL (EFL_2) may be greater than the first EFL (EFL_1) and less than the second EFL (EFL_2). In the third mode, the field of view (FOV) of the camera module may be less than approximately 17 degrees, and the F-number may be less than approximately 5.

[0184] The optical system 1000 can exhibit excellent aberration characteristics in the second mode, as shown in FIGS. 9 and 10. Specifically, FIG. 9 is a graph showing the diffraction MTF characteristics of the optical system 1000 operating in the third mode (second magnification), and FIG. 10 is a graph showing the aberration characteristics. The aberration graph in FIG. 10 shows the longitudinal spherical aberration, astigmatic field curves, and distortion measured from left to right. In FIG. 7, the X axis represents focal length (mm) and distortion (%), and the Y axis represents image height. The spherical aberration graph is for light in wavelength bands of approximately 435 nm, 486 nm, 546 nm, 587 nm, and 656 nm, while the astigmatic and distortion graphs are for light in the 546 nm wavelength band. 10, the closer each curve is to the Y-axis, the better the aberration correction function. Referring to FIG. 10, it can be seen that the measured values ​​of the optical system 1000 according to the embodiment are adjacent to the Y-axis in almost most areas. The optical system 1000 according to the embodiment includes various modes and can provide an autofocus (AF) function for an object by zooming in on the object at a magnification corresponding to each mode.

[0185] In the optical system 1000 according to the embodiment, the first lens group G1, which is closest to the object, is positioned at a fixed position without moving. Therefore, the first to third TTLs (TTL1, TTL2, and TTL3) can have the same values. In the optical system 1000, the fourth lens group G4, which is closest to the image sensor 300, is positioned at a fixed position without moving. Therefore, the first to third BFLs (BFL1, BFL2, and BFL3) can also have the same values. In the optical system 1000, the lenses included in the fixed and movable groups can have non-circular shapes. This structurally ensures a space between the first and fourth lens groups G1 and G4 for the second and third lens groups G2 and G3, significantly reducing the movement distance of the second and third lens groups G2 and G3 when changing the operating mode. Specifically, when changing the operating mode, the second and third lens groups G2 and G3 can each move within a maximum range of 6 mm or less, improving power consumption characteristics. Furthermore, the moving distance of each of the moving groups is significantly reduced compared to TTL, allowing for more precise control of the position of the moving groups. [Table 8] [Table 9]

[0186] Table 8 relates to the focal lengths of the lenses 100, the overall lengths and focal lengths of the lens groups G1, G2, G3, and G4, and the movement distances of the second and third lens groups G2 and G3 for the above-described items in the optical system and camera module according to the embodiment. Referring to Table 8, when the second and third lens groups G2 and G3 move from the first position to the second position or from the second position to the first position, the movement distance of the third lens group G3 may be greater than the movement distance of the second lens group G2. Furthermore, Table 9 relates to the results of Equations 1 to 39 for the optical system 1000 and camera module according to the embodiment. Referring to Table 9, it can be seen that the optical system 1000 and camera module according to the embodiment satisfy at least one of Equations 1 to 39. More specifically, it can be seen that the camera module according to the embodiment satisfies all of Equations 1 to 39. As a result, the embodiment can provide an optical system that has various magnifications by moving at least one lens group and exhibits excellent optical characteristics when providing various magnifications. In particular, the embodiment may have a plurality of lenses 100 having a set number of lenses, a lens group with a set refractive power, a set shape and focal length, a non-circular shape, etc. Also, the embodiment may provide an autofocus (AF) function for the subject at various magnifications by controlling the movement distance of the moving lens group, etc. As a result, the embodiment may be able to photograph a subject at various magnifications using a single camera module, and may prevent degradation of optical performance at each magnification.

[0187] 3, 4, 6, 7, 9, and 10, it can be seen that the optical system 1000 according to the embodiment exhibits little or no significant change in optical characteristics even when the operating mode changes. Specifically, it can be seen that even when the magnification changes within the first to second magnification range due to changes in the positions of the second and third lens groups G2 and G3, there is little or no significant change in the MTF characteristics and aberration characteristics. That is, it can be seen that the optical system 1000 according to the embodiment maintains excellent optical characteristics even when the magnification changes within the first to second magnification range. The embodiment can minimize the movement distance of the moving lens groups by moving only some of the lens groups to control the effective focal length (EFL). For example, in the embodiment, the movement distance of the moving lens groups can be 6 mm or less. Specifically, when the second and third lens groups G2 and G3 move from the first position to the second position or from the second position to the first position, the movement distance of each of the second and third lens groups G2 and G3 can be 6 mm or less. As a result, the optical system 1000 according to the embodiment can significantly reduce the movement distance of the lens group when the magnification is changed, and can minimize the power consumption required when the lens group moves.

[0188] The optical system 1000 according to the embodiment can minimize the diffraction effect caused by non-circular lenses, and each of the plurality of lens groups can correct aberration characteristics or mutually complement aberration characteristics that change with movement. As a result, the optical system 1000 according to the embodiment can minimize or prevent changes in chromatic aberration that occur when magnification changes. In the embodiment, the magnification can be adjusted by moving a lens group other than the first lens group adjacent to the subject among the plurality of lens groups. As a result, the optical system 1000 can have a consistent TTL value even when the lens groups move in accordance with changes in magnification. Therefore, the optical system 1000 and a camera module including the same can be provided with a slimmer structure.

[0189] FIG. 11 is a diagram illustrating a camera module according to an embodiment applied to a mobile terminal.

[0190] Referring to FIG. 11, the mobile terminal 1 may include a camera module 10 provided on the rear side. The camera module 10 may include an image capturing function. The camera module 10 may also include at least one of an autofocus function, a zoom function, and an OIS function. The camera module 10 may process still images or video frames acquired by an image sensor 300 in a capture mode or a video call mode. The processed image frames are displayed on a display unit (not shown) of the mobile terminal 1 and stored in a memory (not shown). Although not shown in the drawing, another camera module is also provided on the front side of the mobile terminal 1.

[0191] For example, the camera module 10 may include a first camera module 10A and a second camera module 10B. At least one of the first camera module 10A and the second camera module 10B may include a driving member that controls the position of the optical system 1000 and at least one lens group, for example, the second and third lens groups G2 and G3, included in the optical system 1000. This allows the camera module 10 to have a slim structure and to capture images of subjects at various magnifications.

[0192] 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 is mainly used under conditions where the image-based autofocus function of the camera module 10 is degraded, such as close range of 10 meters or less or in dark environments. The autofocus device 31 may include a light-emitting unit including a VCSEL (Vertical Cavity Surface Emitting Laser) semiconductor element and a light-receiving unit such as a photodiode that converts optical energy into electrical energy.

[0193] The mobile terminal 1 may further include a flash module 33. The flash module 33 may include a light-emitting element therein for emitting light. The flash module 33 may emit light in the visible light wavelength band. For example, the flash module 33 may emit white light or light of a color similar to white. However, embodiments are not limited thereto, and the flash module 33 may emit light of various colors. The flash module 33 may be activated by operation of the camera of the mobile terminal or by user control.

[0194] 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 one embodiment. Furthermore, the features, structures, effects, etc. exemplified in each embodiment may be combined or modified with other embodiments by a person skilled in the art to which the embodiment belongs. Therefore, such combinations and modifications are to be construed as falling within the scope of the present invention. While the above description focuses on the embodiments, these are merely examples and do not limit the present invention. A person skilled in the art to which the present invention belongs may make various modifications and applications not exemplified above within the scope of the present embodiments, provided that such modifications and applications do not deviate from the essential characteristics of the present embodiments. For example, each component specifically presented in the embodiments may be modified. Such modifications and variations are to be construed as falling within the scope of the present invention, as defined by the appended claims.

Claims

1. First to fourth lens groups are arranged along an optical axis in a direction from the object side to the sensor side, and each lens group includes at least one lens; the first lens group has a refractive power opposite to that of the fourth lens group, the second lens group has a refractive power opposite to that of the third lens group, the first and fourth lens groups are fixed, and the second and third lens groups are movable in the optical axis direction; each of the lenses in the first to fourth lens groups has an object-side surface and a sensor-side surface and is aligned about the optical axis; each of the first and fourth lens groups includes at least one non-circular lens; the non-circular lens has a non-circularity ratio (CH / CA) greater than 0.7; The non-circularity ratio is a ratio of a minimum clear height (CH) to a maximum clear height (CA) of a lens surface having a larger clear aperture (CA) among the object side surface and the sensor side surface of the non-circular lens, a non-circularity of at least one lens included in the first lens group is greater than a non-circularity of at least one lens included in the fourth lens group; the first lens group includes first to third lenses that are sequentially arranged along the optical axis in a direction from the object side to the sensor side, The first lens is the lens closest to the object, the object side surface of the first lens has a convex shape, a sensor side surface of the first lens has a concave shape; the first and second lenses are non-circular lenses; the non-circularity of the first lens is smaller than the non-circularity of the second lens; the second lens group includes at least two lenses, The absolute values ​​of the focal lengths of the first to fourth lens groups are largest in the order of the first lens group, the fourth lens group, the third lens group, and the second lens group.

2. the second lens group includes fourth and fifth lenses sequentially arranged along the optical axis in a direction from the object side to the sensor side, the third lens group includes sixth and seventh lenses sequentially arranged along the optical axis in a direction from the object side to the sensor side, the fourth lens group includes an eighth lens, The optical system of claim 1 , wherein the eighth lens is the lens closest to the image sensor.

3. The present invention includes first to fourth lens groups each including at least one lens, the first to fourth lens groups being arranged along an optical axis in a direction from the object side to the sensor side, the first lens group has a refractive power opposite to that of the fourth lens group, the second lens group has a refractive power opposite to that of the third lens group, the first and fourth lens groups are fixed, and the second and third lens groups are movable in the optical axis direction; each of the lenses in the first to fourth lens groups has an object-side surface and a sensor-side surface and is aligned about the optical axis; each of the first and fourth lens groups includes at least one non-circular lens; the non-circular lens has a non-circularity ratio (CH / CA) greater than 0.7; The non-circularity ratio is a ratio of a minimum clear height (CH) to a maximum clear height (CA) of a lens surface having a larger clear aperture (CA) among the object side surface and the sensor side surface of the non-circular lens, a non-circularity of at least one lens included in the first lens group is greater than a non-circularity of at least one lens included in the fourth lens group; the first lens group includes first to third lenses that are sequentially arranged along the optical axis in a direction from the object side to the sensor side, The first lens is the lens closest to the object, the object side surface of the first lens has a convex shape, a sensor side surface of the first lens has a concave shape; the first and second lenses are non-circular lenses; the non-circularity of the first lens is smaller than the non-circularity of the second lens; the second lens group includes at least two lenses, the second lens group includes fourth and fifth lenses sequentially arranged along the optical axis in a direction from the object side to the sensor side, the third lens group includes sixth and seventh lenses sequentially arranged along the optical axis in a direction from the object side to the sensor side, the fourth lens group includes an eighth lens, The eighth lens is the lens closest to the image sensor, The fourth and fifth lenses have the same non-circularity ratio and are circular lenses with a non-circularity ratio of 1.

4. The present invention includes first to fourth lens groups each including at least one lens, the first to fourth lens groups being arranged along an optical axis in a direction from the object side to the sensor side, the first lens group has a refractive power opposite to that of the fourth lens group, the second lens group has a refractive power opposite to that of the third lens group, the first and fourth lens groups are fixed, and the second and third lens groups are movable in the optical axis direction; each of the lenses in the first to fourth lens groups has an object-side surface and a sensor-side surface and is aligned about the optical axis; each of the first and fourth lens groups includes at least one non-circular lens; the non-circular lens has a non-circularity ratio (CH / CA) greater than 0.7; The non-circularity ratio is a ratio of a minimum clear height (CH) to a maximum clear height (CA) of a lens surface having a larger clear aperture (CA) among the object side surface and the sensor side surface of the non-circular lens, a non-circularity of at least one lens included in the first lens group is greater than a non-circularity of at least one lens included in the fourth lens group; the first lens group includes first to third lenses that are sequentially arranged along the optical axis in a direction from the object side to the sensor side, The first lens is the lens closest to the object, the object side surface of the first lens has a convex shape, a sensor side surface of the first lens has a concave shape; the first and second lenses are non-circular lenses; the non-circularity of the first lens is smaller than the non-circularity of the second lens; the second lens group includes at least two lenses, the second lens group includes fourth and fifth lenses sequentially arranged along the optical axis in a direction from the object side to the sensor side, the third lens group includes sixth and seventh lenses sequentially arranged along the optical axis in a direction from the object side to the sensor side, the fourth lens group includes an eighth lens, The eighth lens is the lens closest to the image sensor, The optical system, wherein the third lens is a circular lens having a non-circularity ratio of 1.

5. The present invention includes first to fourth lens groups each including at least one lens, the first to fourth lens groups being arranged along an optical axis in a direction from the object side to the sensor side, the first lens group has a refractive power opposite to that of the fourth lens group, the second lens group has a refractive power opposite to that of the third lens group, the first and fourth lens groups are fixed, and the second and third lens groups are movable in the optical axis direction; each of the lenses in the first to fourth lens groups has an object-side surface and a sensor-side surface and is aligned about the optical axis; each of the first and fourth lens groups includes at least one non-circular lens; the non-circular lens has a non-circularity ratio (CH / CA) greater than 0.7; The non-circularity ratio is a ratio of a minimum clear height (CH) to a maximum clear height (CA) of a lens surface having a larger clear aperture (CA) among the object side surface and the sensor side surface of the non-circular lens, a non-circularity of at least one lens included in the first lens group is greater than a non-circularity of at least one lens included in the fourth lens group; the first lens group includes first to third lenses that are sequentially arranged along the optical axis in a direction from the object side to the sensor side, The first lens is the lens closest to the object, the object side surface of the first lens has a convex shape, a sensor side surface of the first lens has a concave shape; the first and second lenses are non-circular lenses; the non-circularity of the first lens is smaller than the non-circularity of the second lens; the second lens group includes at least two lenses; the second lens group includes fourth and fifth lenses sequentially arranged along the optical axis in a direction from the object side to the sensor side, the third lens group includes sixth and seventh lenses sequentially arranged along the optical axis in a direction from the object side to the sensor side, the fourth lens group includes an eighth lens, The eighth lens is the lens closest to the image sensor, The optical system, wherein the third lens group includes at least one lens having a non-circular shape.

6. the sixth and seventh lenses are non-circular lenses, The optical system of claim 5 , wherein the sixth lens has a non-circularity greater than the seventh lens.

7. the first lens has a positive refractive power; The optical system according to claim 2 , wherein the eighth lens has the smallest non-circularity.

8. a non-circularity of at least one lens included in the second lens group is greater than a non-circularity of each of the non-circular lenses included in the first and fourth lens groups; the second and third lens groups have a first magnification when positioned at a first position, and have a second magnification when positioned at a second position different from the first position; The optical system of claim 1 , wherein the second magnification is greater than the first magnification.

9. When the second and third lens groups are located at the first position, it has a first effective focal length (Effective Focal Length, EFL), and when located at the second position, it has a second effective focal length greater than the first effective focal length. The optical system according to claim 8.

10. m_G2 is the moving distance when the second lens group moves from the first position to the second position or from the second position to the first position. TTL (Total track length) is the distance on the optical axis from the object side surface of the lens closest to the object in the first lens group to the upper surface of the sensor. The optical system according to claim 9, satisfying the mathematical formula: 0.05 < m_G2 / TTL < 0.

5.

11. m_G3 is the moving distance when the third lens group moves from the first position to the second position or from the second position to the first position. TTL (Total track length) is the distance on the optical axis from the object side surface of the lens closest to the object in the first lens group to the upper surface of the sensor. The optical system according to claim 9, satisfying the mathematical formula: 0.05 < m_G3 / TTL < 0.

5.

12. When the second and third lens groups move from the first position to the second position or from the second position to the first position, the moving distance of the third lens group is greater than the moving distance of the second lens group. The optical system according to claim 9.

13. When the second and third lens groups move from the first position to the second position or from the second position to the first position, the moving distance of each of the second and third lens groups is 6 mm or less. The optical system according to claim 12.

14. Including an optical system and a driving member. The optical system includes the optical system according to claim 1. The driving member controls the positions of the second and third lens groups. A camera module.

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