Optical system and camera module

Abstract

An optical system according to an embodiment of the present invention includes: first to third lens groups arranged along an optical axis from an object side to a sensor side, in which the first lens group and the third lens group have negative refractive power, the second lens group has positive refractive power, a position of the first lens group is fixed, and a position of the second lens group is fixed; the second lens group and the third lens group are movable in an optical axis direction, and an optical system having the first to third lens groups has operation modes of different magnification times according to movement of at least one of the second lens group and the third lens group, at least one of the second lens group and the third lens group includes a lens having the thickest center thickness among the lenses, and an optical axis distance between a surface of a lens closest to an object among the lenses of the first lens group and an imaging surface of the image sensor is TTL. The size of the entrance pupil diameter at the highest magnification in the operation mode of the optical system is EPD3, and the following formula can be satisfied: 2 < TTL / EPD3 < 7.

Description

Technical Field

[0001] Embodiments of the present invention relate to an optical system for improving optical performance and a camera module including the optical system. Background Art

[0002] The camera module captures an object and stores it as an image or video, and is installed in various applications. In particular, the camera module is produced in a very small size and is applied not only to portable devices such as smart phones, tablet PCs, and notebook computers, but also to drones and vehicles to provide various functions. For example, the optical system of the camera module may include an imaging lens for forming an image, and an image sensor for converting the formed image into an electrical signal. In this case, the camera module can perform an autofocus (AF) function of aligning the focal length of the lens by automatically adjusting the distance between the image sensor and the imaging lens, and can perform a zoom function of zooming in or out by increasing or decreasing the magnification of a distant object through a zoom lens. In addition, the camera module adopts image stabilization (IS) technology to correct or prevent image stabilization problems caused by an unstable fixture or camera movement caused by the user's movement.

[0003] The most important element of the camera module for obtaining an image is the imaging lens that forms the image. Recently, there has been growing interest in high efficiency, such as high image quality and high resolution, and in order to achieve this, research is underway on optical systems including multiple lenses. For example, research is underway to use multiple imaging lenses with positive (+) and / or negative (-) refractive powers to achieve an efficient optical system. When an optical system includes multiple lenses, there is a problem that it is difficult to obtain excellent optical characteristics and aberration characteristics. In addition, when multiple lenses are included, the total length, height, etc. may increase due to the thickness, spacing, size, etc. of the multiple lenses, thereby increasing the total size of the module including the multiple lenses.

[0004] Image sensors are increasing in size to achieve high resolution and high definition. However, as the size of image sensors increases, the total track length (TTL) of an optical system including multiple lenses also increases, thereby increasing the thickness of cameras and mobile terminals including the optical system.

[0005] When an optical system includes a plurality of lenses, the position of at least one lens or a lens group including at least one lens can be controlled to perform functions such as zooming and autofocus (AF). However, when a lens or a lens group performs this function, the amount of movement of the lens or the lens group may increase exponentially. Therefore, a problem with the optical system is that the movement of the lens or the lens group may require a large amount of energy and a large volume considering the amount of movement. In addition, there is a problem of degradation of aberration characteristics due to the movement of the lens or the lens group. Therefore, when performing zooming and autofocus (AF) functions, there is a problem that the optical characteristics deteriorate at a specific magnification. Therefore, there is a need for a new optical system that can solve the above problems. Summary of the Invention

[0006] Technical issues

[0007] Embodiments of the present invention provide an optical system with improved optical characteristics. Embodiments provide an optical system and a camera module capable of capturing images at various magnifications. Embodiments provide an optical system and a camera module with improved aberration characteristics at various magnifications. Embodiments provide an optical system and a camera module that can be implemented in a small and compact manner.

[0008] Technical Solution

[0009] According to an embodiment of the present invention, an optical system includes: a first lens group to a third lens group, which are arranged along the optical axis from the object side to the sensor side, and each includes at least one lens, wherein the first lens group and the third lens group have negative refractive power, the second lens group has positive refractive power, the position of the first lens group is fixed, the number of lenses in the second lens group is smaller than the number of lenses in the first lens group, the second lens group and the third lens group are movable in the optical axis direction, and the optical system having the first lens group to the third lens group has an operating mode with different magnifications according to the movement of at least one of the second lens group and the third lens group, at least one of the second lens group and the third lens group includes a lens with the thickest center thickness among the lenses, and the optical axis distance between the surface of the lens of the first lens group closest to the object side and the imaging surface of the image sensor is TTL, and the size of the incident pupil diameter of the optical system at the highest magnification in the operating mode is EPD3, and satisfies the following formula: 2<TTL / EPD3<7.

[0010] According to an embodiment of the present invention, the optical axis distance between the lens closest to the image sensor in the third lens group and the image sensor can be changed according to the operating mode, and the optical axis distance between the object-side surface of the lens closest to the object in the first lens group and the sensor-side surface of the lens closest to the image sensor in the third lens group can be changed according to the operating mode.

[0011] According to an embodiment of the present invention, the operating mode includes a wide-angle mode, which is Mode_1, and in the wide-angle mode, the optical axis distance between the first lens group and the second lens group is DG12, and the optical axis distance between the second lens group and the third lens group is DG23, and the following formula can be satisfied: 1<Mode1(DG12 / DG23)<5.

[0012] According to an embodiment of the present invention, the operating mode includes a telephoto mode, which is Mode3. In the telephoto mode, the optical axis distance between the first lens group and the second lens group is DG12, and the optical axis distance between the second lens group and the third lens group is DG23, and the following formula can be satisfied: 0<Mode3(DG12 / DG23)<0.7.

[0013] According to an embodiment of the present invention, a maximum distance between adjacent lenses according to an operation mode is Mode_CG_Max, and a minimum distance between adjacent lenses according to an operation mode is Mode_CG_Min, and the following formula may be satisfied: 2<Mode_CG_Max / Mode_CG_Min<8.

[0014] According to an embodiment of the present invention, the number of lenses in the first lens group is 3, the number of lenses in the third lens group is 2 or 3, and the absolute values ​​of the focal lengths of the first lens group and the third lens group may be greater than the focal length of the second lens group.

[0015] According to an embodiment of the present invention, the optical system includes a wide-angle mode with a first effective focal length (EFL1), a medium focal length mode with a second effective focal length (EFL2), and a telephoto mode with a third effective focal length (EFL3), and can satisfy the following formula: EFL1<ELF2<EFL3.

[0016] According to an embodiment of the present invention, the field of view in wide-angle mode is FOV1, the field of view in medium focus mode is FOV2, and the field of view in telephoto mode is FOV3, and the following formula can be satisfied: 8 degrees < FOV3 < FOV2 < FOV1 < 45 degrees.

[0017] According to an embodiment of the present invention, the second lens group may include an object side lens having an aspherical surface made of glass and having a biconvex shape and a sensor side lens having an aspherical surface made of plastic on the sensor side of the object side lens.

[0018] An optical system according to an embodiment of the present invention includes: a first lens group having first to third lenses; a second lens group having fourth and fifth lenses; and a third lens group having at least two lenses, wherein the first lens group, the second lens group, and the third lens group are arranged from the object side toward the sensor side in the optical axis direction, the first lens has positive refractive power and has a convex shape on the object side surface, the third lens has negative refractive power and has concave shapes on both sides, the fourth lens has positive refractive power and has a convex shape on both sides, the last lens closest to the image sensor in the third lens group has negative refractive power, the second lens group and the third lens group are moved in the optical axis direction, and the optical axis distance between the last lens and the image sensor can be changed according to the operation mode.

[0019] According to an embodiment of the present invention, the first lens group may have negative (-) refractive power, the first lens may have a meniscus shape convex toward the object side, the second lens may have a meniscus shape convex toward the sensor side, and the second lens and the fifth lens may have negative refractive power.

[0020] According to an embodiment of the present invention, the fourth lens and the last lens may have a refractive index less than 1.6, the fourth lens may be made of glass, and lenses other than the fourth lens may be made of plastic.

[0021] According to an embodiment of the present invention, the maximum length of the first lens in a first direction perpendicular to the optical axis and the maximum length in the second direction may be different from each other, and the maximum length of the first lens in the first direction and the second direction may be the largest among the lenses, and the difference between the center thickness and the edge thickness of the fifth lens may be 0.9 or more, and the difference between the center thickness and the edge thickness of the sixth lens may be 0.9 or more.

[0022] According to an embodiment of the present invention, the optical axis distance between the first lens group and the second lens group and the optical axis distance between the second lens group and the third lens group are greater than or equal to 0.2 mm and less than or equal to 8 mm, the optical axis distance from the center of the object-side surface of the fourth lens to the center of the sensor-side surface of the fifth lens is DG2, and the optical axis distance from the object-side surface of the first lens to the imaging surface of the image sensor is TTL, and the following formula can be satisfied: 3<TTL / DG2<10.

[0023] A camera module according to an embodiment of the present invention includes an optical system including the above-described optical system and a driving member that can move at least one of the second lens group and the third lens group in an optical axis direction according to an operation mode of the optical system.

[0024] Beneficial effects

[0025] Optical systems and camera modules according to embodiments have various magnifications and can exhibit excellent optical properties when providing various magnifications. Specifically, embodiments can control the movement distances of the various moving lens groups to achieve various magnifications and provide autofocus functionality for an object. Optical systems and camera modules according to embodiments can compensate for the aberration characteristics of multiple lens groups or compensate for changes in aberration characteristics caused by movement. Thus, optical systems according to embodiments can minimize or prevent chromatic aberration and changes in aberration characteristics that occur when the magnification changes.

[0026] The optical system and camera module according to the embodiment can control the effective focal length (EFL) by moving only a portion of the multiple lens groups, and can minimize the moving distance of the mobile lens group. Therefore, the optical system can reduce the moving distance of the mobile lens group according to the change of the operating mode and minimize the power consumption required when the lens group moves. The optical system can have at least one lens included in the fixed group, and the mobile group has a non-circular shape. Therefore, the optical system can reduce the height of the optical system while maintaining optical performance and ensure that the lens groups arranged between the multiple lens groups have space for structural arrangement.

[0027] The optical system and camera module according to the embodiments can adjust the magnification to magnify or reduce an object by moving lens groups other than the first lens group adjacent to the object among multiple lens groups. Therefore, even when the lens groups are moved according to the magnification change to have multiple focal lengths, the optical system can maintain a constant TTL value and can be applied to a camera module with linear zoom. As a result, the optical system and the camera module including the optical system can be provided with a lighter and thinner structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a configuration diagram of an optical system and a camera module having the optical system according to a first embodiment.

[0029] Figure 2 It's a change Figure 1 An example of a first mode of an optical system.

[0030] Figure 3 It's a change Figure 1 and Figure 2 An example of the third mode in an optical system.

[0031] Figure 4 is a lens data table of the optical system according to the first embodiment.

[0032] Figure 5 is a graph showing relative illuminance according to positions in a wide-angle mode, a mid-focus mode, and a telephoto mode according to the first embodiment.

[0033] Figure 6 is a graph of diffraction MTF in the optical system in the first mode (wide-angle mode) according to the first embodiment.

[0034] Figure 7 is a graph of diffraction MTF in the optical system in the second mode (middle focus mode) according to the first embodiment.

[0035] Figure 8 is a graph of the diffraction MTF in the optical system in the third mode (telephoto mode) according to the first embodiment.

[0036] Figure 9 is a graph showing aberration characteristics in the optical system according to the first mode of the first embodiment.

[0037] Figure 10 is a graph showing aberration characteristics in the optical system according to the second mode of the first embodiment.

[0038] Figure 11 is a graph showing aberration characteristics in the optical system according to the third mode of the first embodiment.

[0039] Figure 12 is a configuration diagram of an optical system and a camera module having the same according to a second embodiment.

[0040] Figure 13 yes Figure 12 An example of a change of the first mode of the optical system.

[0041] Figure 14 yes Figure 12 and Figure 13 An example of a change of the third mode in the optical system.

[0042] Figure 23 is Figure 12 The optical system has a configuration of a reflecting mirror.

[0043] Figure 15 is a lens data table of the optical system according to the second embodiment.

[0044] Figure 16 is a graph showing relative illuminance according to positions in a wide-angle mode, a mid-focus mode, and a telephoto mode according to the second embodiment.

[0045] Figure 17 is a graph showing the diffraction MTF in the optical system in the first mode (wide-angle mode) according to the second embodiment.

[0046] Figure 18 is a graph showing the diffraction MTF in the optical system in the second mode (middle focus mode) according to the second embodiment.

[0047] Figure 19 is a graph showing the diffraction MTF in the optical system in the third mode (telephoto mode) according to the second embodiment.

[0048] Figure 20 is a graph showing aberration characteristics in the optical system according to the first mode of the second embodiment.

[0049] Figure 21 is a graph showing aberration characteristics in the optical system according to the second mode of the second embodiment.

[0050] Figure 22 is a graph showing aberration characteristics in the optical system according to the third mode of the second embodiment.

[0051] Figure 23 is a configuration of an optical system having a reflecting mirror according to the first embodiment and the second embodiment.

[0052] Figure 24 1 and 2 are diagrams illustrating that the camera modules according to the first and second embodiments of the present invention are applied to a mobile terminal. DETAILED DESCRIPTION

[0053] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The technical spirit of the present invention is not limited to the partial embodiments to be described, but can be implemented in various other forms, and within the scope of the technical spirit of the present invention, one or more components can be selectively combined and used in place of each other. In addition, unless specifically defined and clearly described, the terms (including technical terms and scientific terms) used in the embodiments of the present invention can be interpreted as meanings that are generally understood by ordinary technicians in the field to which the present invention belongs, and commonly used terms (for example, terms defined in dictionaries) should be able to interpret their meanings in consideration of the contextual meaning of the relevant technology.

[0054] The terms used in the embodiments of the present invention are used to illustrate the embodiments and are not intended to limit the present invention. In this specification, unless otherwise specifically stated in the wording, the singular form may also include the plural form, and in the case of describing at least one (or one or more) of A and (and) B, C, it may include one or more of all combinations that A, B, and C can be combined. When describing the components of the embodiments of the present invention, terms such as first, second, A, B, (a), and (b) may be used. These terms are only used to distinguish a component from other components, and the properties, order, or process of the corresponding components may not be limited by these terms. And when describing a component as being "connected," "combined," or "engaged" with another component, the description may include not only being directly connected, combined, or engaged with other components, but also being "connected," "combined," or "engaged" between the component and the other components by another component. In addition, when described as being formed or arranged "above (upper)" or "below (lower)" of each component, the description may include not only being formed or arranged "above (upper)" or "below (lower)" of each component, but also being formed or arranged between the two components by one or more other components. In addition, when expressed as "above (upper)" or "below (lower)", it can refer to the downward direction as well as the upward direction relative to an element. Unless it is specifically stated that the several embodiments described below cannot be combined with each other, they can be combined with each other. In addition, unless otherwise specified, the description of other embodiments can be applied to the parts omitted from the description of any one of the several embodiments.

[0055] In the description of the present invention, the convex surface of the lens may mean that the lens surface in the area corresponding to the optical axis has a convex shape based on the optical axis, and the concave surface of the lens may mean that the lens surface in the area corresponding to the optical axis has a concave shape. In addition, the "object side surface" may mean the surface of the lens facing the object side based on the optical axis, and the "sensor side surface" may mean the surface of the lens facing the imaging surface (image sensor) based on the optical axis. In addition, the center thickness of the lens may mean the thickness of the lens in the direction of the optical axis. In addition, the vertical direction may mean the direction perpendicular to the optical axis, and the end of the lens or the lens surface may mean the end of the effective area through which the incident light of the lens passes. In addition, depending on the measurement method, etc., the size of the effective diameter of the lens surface may have a measurement error of up to ±0.4 mm.

[0056] Figures 1 to 11 1 and 2 are diagrams illustrating an optical system according to a first embodiment of the present invention.

[0057] Reference Figures 1 to 11According to the first embodiment, the optical system 1000 may include a plurality of lens groups G1, G2, and G3. The plurality of lens groups G1, G2, and G3 may include at least two lens groups movable in the direction of the optical axis OA and at least one lens group fixed in position. The plurality of lens groups G1, G2, and G3 may include a fixed lens group located on the object side and a movable lens group located on the sensor side. Here, the object side refers to the area within the optical system 1000 adjacent to the object, and the sensor side refers to the area within the optical system 1000 adjacent to the image sensor 300.

[0058] The movable lens group may include an object-side lens group and a sensor-side lens group. The fixed lens group may be defined as a first lens group G1, the object-side movable lens group may be defined as a second lens group G2, and the sensor-side movable lens group may be defined as a third lens group G3. The second lens group G2 may be arranged between the first lens group G1 and the third lens group G3. The first lens group G1 collects incident light, the second lens group G2 changes the zoom ratio (focal length), and the third lens group G3 can adjust the focus position on the image plane of the image sensor 300.

[0059] The first lens group G1 may include a greater number of lenses than the second lens group G2. The third lens group G3 may include a smaller number of lenses than the first lens group G1. The multiple lenses of the first lens group G1 may include at least three lenses for adjusting the amount of incident light, diopter, and chromatic aberration. The second lens group G2 and the third lens group G3 may include at least two lenses. For example, the optical system may further include at least one lens fixed between the third lens group G3 and the image sensor 300.

[0060] The first lens group G1, the second lens group G2, and the third lens group G3 may be arranged sequentially along the optical axis OA from the object side toward the sensor. The optical system 1000 may include an image sensor 300 arranged on the sensor side of the third lens group G3. The optical system 1000 may include an optical filter 500 arranged on the object side of the image sensor 300.

[0061] Each of the first lens group G1, the second lens group G2, and the third lens group G3 may have positive (+) or negative (-) refractive power. In the optical system 1000, the lens groups with positive refractive power may be at least two lens groups, and the lens group with negative refractive power may be a single lens group. 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 negative (-) refractive power. The absolute value of the refractive power of the first lens group G1 may be greater than the absolute values ​​of the refractive power of the second lens group G2 and the third lens group G3. For example, the absolute value of the refractive power of the first lens group G1 may be at least twice the absolute value of the refractive power of the second lens group G2. Thus, the first lens group G1 can disperse incident light. The first and third lens groups (G1, G3) may have negative refractive power, and the second lens group G2 may have positive refractive power.

[0062] The focal length of the second lens group G2 may have an opposite sign to that of the first lens group G1. The focal length of the second lens group G2 may have a positive (+) sign, and the focal length of the first lens group G1 may have a negative (-) sign. Diopter is the reciprocal of focal length. As described above, since the second lens group G2 and the third lens group G3 have opposite diopters, the focal length of the second lens group G2 may have an opposite sign (+, -) to that of the third lens group G3. For example, the focal length of the second lens group G2 may have a positive (+) sign, and the focal length of the third lens group G3 may have a negative (-) sign.

[0063] The absolute value of the focal length of each of the first lens group G1, the second lens group G2, and the third lens group G3 can decrease in order of the first lens group G1, the third lens group G3, and the second lens group G2. The first lens group G1 is fixed in place, while the second lens group G2 and the third lens group G3 are movable in the direction of the optical axis OA. Therefore, the optical system 1000 can provide various magnifications by moving the second lens group G2 and the third lens group G3. The first lens group G1, the second lens group G2, and the third lens group G3 will be described in more detail below. The first lens group G1 can include at least two lenses with opposite refractive powers. For example, the first lens group G1 can include three lenses. The first lens group G1 can have more lenses with positive refractive power than lenses with negative refractive power.

[0064] The multiple lenses included in the first lens group G1 may have set intervals. Specifically, the center distances between the multiple lenses included in the first lens group G1 may be fixed intervals according to the operation mode described below. For example, the center distance (CG1) between the first lens 101 and the second lens 102, and the center distance (CG2) between the second lens 102 and the third lens 103 may not change depending on the operation mode and may have a constant distance. Here, the center distance (CG) between the lenses may represent the optical axis distance between adjacent lenses.

[0065] The second lens group G2 may include a plurality of lenses. Specifically, the second lens group G2 may include three or fewer lenses having different diopters. 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 having the same diopter. The plurality of lenses included in the second lens group G2 may have a set distance. Specifically, the center distance (CG) between the plurality of lenses included in the second lens group G2 may be a fixed distance according to the operating mode described below. For example, the center distance CG4 between the fourth lens 104 and the fifth lens 105 may not change according to the operating mode and may have a constant distance.

[0066] The third lens group G3 may include multiple lenses. Specifically, the third lens group G3 may include two or more lenses having refractive powers. The lenses included in the third lens group G3 may have negative refractive powers. 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 multiple lenses included in the third lens group G3 may have a set distance. Specifically, even when the operating mode described later changes, the center distances between the multiple lenses included in the third lens group G3 may remain constant and not change. For example, the center distance CG6 between the sixth lens 106 and the seventh lens 107 may be constant and not change depending on the operating mode. The distance DG4 between the last lens included in the third lens group G3 and the optical filter 500 may vary depending on the operating mode. In addition, the distance between the last lens and the image sensor 300 is BFL and may vary depending on the operating mode.

[0067] The lens unit 100 includes a plurality of lens groups G1, G2, and G3. The lens unit 100 may include first to seventh lenses 101 to 107. The first lens group G1 may include a first lens 101, a second lens 102, and a third lens 103, and the second lens group G2 may include a fourth lens 104 and a fifth lens 105. In addition, the third lens group G3 may include a sixth lens 106 and a seventh lens 107. The first to seventh lenses 101 to 107 and the image sensor 300 may be arranged in sequence along the optical axis OA of the optical system 1000.

[0068] At least one of the lenses 101 to 103 of the first lens group G1 may have different lengths in the first direction Y and the second direction X, which are orthogonal to the optical axis. At least one of the lenses 101 to 103 of the first lens group G1 may include a non-circular lens. At least one of the lenses 104 and 105 of the second lens group G2 may have different lengths in the first direction Y and the second direction X, which are orthogonal to the optical axis, and, for example, may include a non-circular lens. At least one of the lenses 105 to 107 of the third lens group G3 may have different lengths in the first direction Y and the second direction X, which are orthogonal to the optical axis, and, for example, may include a non-circular lens. For example, the first lens 101, which has the largest effective length among the lenses, may have different lengths in the first direction Y and the second direction X. In addition, the fourth lens 104, which has the larger effective length among the lenses 104 and 105 of the second lens group G2, may have different lengths in the first direction Y and the second direction X. The optical system 1000 according to the first embodiment has improved assemblability due to the non-circular lenses and can be mechanically stable. In addition, the optical system 1000 can significantly reduce the moving distance of the moving lens group and provide various magnifications.

[0069] Each lens may include an effective area and an ineffective area. The effective area is an area having an effective length and may be the area through which light incident on each of the first to seventh lenses 101 to 107 passes. The effective area may be an area that refracts incident light to achieve optical properties. The ineffective area may be arranged around the effective area. The ineffective area may be an area where light is not incident. In other words, the ineffective area may be an area unrelated to the optical properties. Alternatively, the ineffective area may be an area fixed to the lens barrel (not shown) that houses the lens.

[0070] The image sensor 300 can detect light. The image sensor 300 can detect light that has sequentially passed through the lens unit 100 (e.g., the first lens 101 to the seventh lens 107). The image sensor 300 may include a CCD (charge coupled device) or a CMOS (complementary metal oxide semiconductor). The optical filter 500 may be arranged between the lens unit 100 and the image sensor 300. The optical filter 500 may be placed between the image sensor 300 and the fourth lens group G4. For example, the optical filter 500 may be placed between the seventh lens 107 of the fourth lens group G4 and the image sensor 300.

[0071] The optical filter 500 may include at least one of an infrared filter and protective glass. The optical filter 500 allows light of a predetermined wavelength band to pass through and filters light of a different wavelength band. When the optical filter 500 includes an infrared filter, it can block radiant heat emitted from external light from being transmitted to the image sensor 300. The optical filter 500 can transmit visible light and reflect infrared light.

[0072] The optical system 1000 may include an aperture stop (not shown). The aperture stop can adjust the amount of light incident on the optical system 1000. The aperture stop can be located around the object-side surface of the first lens 101 or can be arranged between two lenses selected from the first to seventh lenses 101 to 107. For example, the aperture stop can be arranged around the third lens 103 and the fourth lens 104. The aperture stop can be arranged around the sensor-side surface of the third lens 103 or around the object-side surface of the fourth lens 104. Alternatively, at least one of the first to seventh lenses 101 to 107 can function as the aperture stop. For example, the exterior of the object-side surface or sensor-side surface of one of the lenses selected from the first to seventh lenses 101 to 107 can function as the aperture stop for controlling the amount of light. For example, at least one of the sensor-side surface of the third lens 103 and the object-side surface of the fourth lens 104 can function as the aperture stop.

[0073] The object-side and sensor-side surfaces of the first through seventh lenses 101 through 107 may be aspherical. At least one of the first through seventh lenses 101 through 107 may be made of a glass molded material. For example, at least one of the third and fourth lenses 103 and 104 may be a glass molded lens; specifically, the fourth lens 104 may be made of a glass molded material. The first, second, third, and eighth lenses 101, 102, 103, 105, 106, 107, and 108 may be made of plastic. The placement of glass molded lenses in the lens unit 100 can reduce TTL.

[0074] The optical system 1000 may further include: Figure 23 The optical path changing member 400 is shown. The optical path changing member 400 can reflect light incident from the outside to change the light's path from the second path OA2 to the first path OA1. The optical path changing member 400 may include a reflector or a prism. For example, the optical path changing member 400 may include a right-angle prism. When the optical path changing member 400 includes a right-angle prism, the optical path changing member 400 can reflect the second path OA2 of the incident light at an angle of 90 degrees to change the first path OA1 of the light. The first path OA1 may be located along the optical axis of the optical system. The optical path changing member 400 may be arranged closer to the object side than the lens unit 100. That is, when the optical system 1000 includes the optical path changing member 400, the optical path changing member 300, the first lens 101, the second lens 102, the third lens 103, the fourth lens 104, the fifth lens 105, the sixth lens 106, the seventh lens 107, the optical filter 500, and the image sensor 300 may be arranged in this order from the object side toward the sensor.

[0075] The optical path changing member 400 can change the path of light incident from the outside to a set direction. For example, the optical path changing member 400 can change the second path OA2 of light incident on the optical path changing member 400 in a first direction to the first path OA1 in a second direction, which is the arrangement direction of the lens unit 100. If the optical system 1000 includes the optical path changing member 400, the optical system can be applied to a foldable camera, thereby reducing the thickness of the camera. Specifically, if the optical system 1000 includes the optical path changing member 400, light incident in a direction Y perpendicular to the surface of the device to which the optical system 1000 is applied can be changed to a direction Z parallel to the surface of the device. Therefore, the optical system 1000 including the lens unit 100 can have a thinner thickness within the device, thereby reducing the height of the device.

[0076] If the optical system 1000 does not include an optical path changing member, the lens unit 100 can be arranged to extend in a direction Y perpendicular to the surface of the device within the device. Therefore, the optical system 1000 including the lens unit 100 has a high height in the direction Y perpendicular to the surface of the device, and it may be difficult to make the optical system 1000 and the device including it thinner. However, when the optical system 1000 includes the optical path changing member 400, the lens unit 100 can be arranged to extend in a direction Z 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 folding camera. Therefore, the optical system 1000 including the lens unit 100 can have a low height in the direction perpendicular to the surface of the device. Therefore, the camera including the optical system 1000 can have a thinner thickness within the device, and the thickness of the device can also be reduced.

[0077] As another example, the optical path changing member may be arranged between two lenses of the lens unit 100, or may be arranged between the last lens adjacent to the image sensor 300 and the image sensor 300. As another example, the optical path changing member may be provided in multiple pieces. Specifically, multiple optical path changing members may be arranged between the object and the image sensor 300. For example, the multiple optical path changing members may include a first optical path changing member arranged closer to the object side than the lens unit 100, and a second optical path changing member arranged between the last lens and the image sensor 300. Therefore, the optical system 1000 can have various shapes and heights depending on the camera to which it is applied, and can have improved optical performance.

[0078] Reference Figures 1 to 3 , the first lens group G1 may include a first lens 101, a second lens 102, and a third lens 103, the second lens group G2 may include a fourth lens 104 and a fifth lens 105, and the third lens group G3 may include a sixth lens 106 and a seventh lens 107. The first lens 101 may be closest to the object side of the lens unit 100, and the seventh lens 107 may be closest to the image sensor 300 side. Each of the first to seventh lenses 101 to 107 may include object-side surfaces S1, S3, S5, S7, S9, S11, and S13 and sensor-side surfaces S2, S4, S8, S10, S12, and S14.

[0079] The first lens 101 can have a positive (+) refractive power along the optical axis OA. The first lens 101 can be made of a plastic material or a glass material, and can be, for example, a plastic material. The object-side first surface S1 of the first lens 101 can have a convex shape along the optical axis OA, and the sensor-side second surface S2 can have a concave shape along the optical axis OA. That is, the first lens 101 can have a meniscus shape that is convex toward the object side along the optical axis OA. Alternatively, the first lens 101 can have a second surface S2 that is convex at the optical axis OA. At least one or both of the first surface S1 and the second surface S2 can be aspherical. The center thickness CT1 of the first lens 101 is the thickness along the optical axis and can be thicker than the edge thickness ET1. The edge thickness ET1 is the optical axis distance between the edge of the object-side surface and the edge of the sensor-side surface of the first lens 101. Therefore, the first lens 101 can improve optical aberrations or control incident light. The first surface S1 and the second surface S2 can be arranged so that there is no critical point from the optical axis to the end of the active area.

[0080] The second lens 102 can have positive (+) or negative (-) refractive power along the optical axis OA, for example, it can have positive refractive power. The second lens 102 can be made of a plastic material or a glass material, for example, it can be a plastic material. The object-side third surface S3 of the second lens 102 can have a concave shape on the optical axis OA, and the sensor-side fourth surface S4 can have a convex shape on the optical axis OA. The second lens 102 can have a meniscus shape that convexes from the optical axis OA toward the sensor side. Alternatively, the third surface S3 can have a convex shape on the optical axis OA, and the fourth surface S4 can have a convex shape. That is, the second lens 102 can have a shape that convexes on both sides on the optical axis OA. Alternatively, the third surface S3 can have a concave shape on the optical axis OA, and the fourth surface S4 can have a concave shape on the optical axis OA. Conversely, the third surface S3 can have a convex shape on the optical axis OA, and the fourth surface S4 can have a concave shape on the optical axis OA. At least one or both of the third surface S3 and the fourth surface S4 may be aspherical.The third surface S3 and the fourth surface S4 may be arranged so as to have no critical point from the optical axis to the end of the effective area.

[0081] The third lens 103 may have a refractive power opposite to that of the first lens 101 on the optical axis OA. That is, the third lens 103 may have a negative (-) refractive power. The third lens 103 may include a plastic material or a glass material, and may be, for example, a plastic material. The object-side fifth surface S5 of the third lens 103 may have a concave shape on the optical axis OA, and the sensor-side sixth surface S6 may have a concave shape on the optical axis OA. That is, the third lens 103 may have a shape with two sides concave on the optical axis OA. Alternatively, the fifth surface S5 may have a convex shape on the optical axis OA, and the sixth surface S6 may have a concave shape on the optical axis OA. That is, the third lens 103 may have a meniscus shape that is convex toward the object side on the optical axis OA. At least one or both of the fifth surface S5 and the sixth surface S6 may be aspherical. The fifth surface S5 and the sixth surface S6 may be arranged so that there is no critical point from the optical axis to the end of the effective area.

[0082] The object-side first lens 101 of the first lens group G1 can have a refractive power opposite to that of the sensor-side third lens 103. Therefore, the multiple lenses 101, 102, and 103 included in the first lens group G1 can mutually compensate for any chromatic aberrations that may occur. The third lens 103, which is adjacent to the second lens group G2 in the first lens group G1, can have the highest refractive index within the first lens group G1. For example, the refractive index of the third lens 103 can be 1.6 or less. Therefore, since the first lens group G1 controls the dispersion of light provided to the second lens group G2, the lens size of the second lens group G2 can be reduced.

[0083] The fourth lens 104 may have a positive (+) refractive power on the optical axis OA. The fourth lens 104 may include a plastic material or a glass material, for example, a glass molded material, and may have a refractive index of 1.6 or less. The object-side seventh surface S7 of the fourth lens 104 may have a convex shape on the optical axis OA, and the sensor-side eighth surface S8 may have a convex shape on the optical axis OA. That is, the fourth lens 104 may have a shape that is convex on both sides on the optical axis OA. Alternatively, the seventh surface S7 may be convex on the optical axis OA, and the eighth surface S8 may be concave on the optical axis OA. That is, the fourth lens 104 may have a meniscus shape that is convex toward the object on the optical axis OA. At least one or both of the seventh surface S7 and the eighth surface S8 may be aspherical. The seventh surface S7 and the eighth surface S8 may be arranged so that there is no critical point from the optical axis to the end of the effective area.

[0084] The fifth lens 105 can have positive (+) or negative (-) refractive power on the optical axis OA. The fifth lens 105 can have the same positive refractive power as the fourth lens 104 on the optical axis OA. The fifth lens 105 can be made of a plastic material or a glass material, and for example, can be made of a plastic material. The object-side ninth surface S9 of the fifth lens 105 can have a concave shape on the optical axis OA, and the sensor-side tenth surface S10 can have a convex shape on the optical axis OA. In other words, the fifth lens 105 can have a meniscus shape that convexes from the optical axis OA toward the sensor side. At least one or both of the ninth surface S9 and the tenth surface S10 can be aspherical. The ninth surface S9 of the fifth lens 105 can be configured to be free of at least one critical point. As another example, the ninth surface S9 of the fifth lens 105 can have a convex shape on the optical axis OA, and the tenth surface S10 can have a convex shape on the optical axis OA. In other words, the fifth lens 105 can have a shape that convexes on both sides 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. Conversely, the ninth surface S9 may have a convex shape on the optical axis OA, and the tenth surface S10 may have a concave shape on the optical axis OA.

[0085] The fourth lens 104 has a convex shape on both sides, and the center thickness CT4 of the fourth lens 104 can be thicker than the edge thickness ET4, for example, more than twice. Therefore, the distance CG4 between the fourth lens 104 and the fifth lens 105 can be reduced. The difference in Abbe numbers between the fourth lens 104 and the fifth lens 105 can be greater than 20 or greater than 30, and can be less than 70 at most. Therefore, the second lens group G2 can minimize changes in chromatic aberration caused by position changes according to changes in the operating mode.

[0086] The sixth lens 106 can have positive (+) or negative (-) refractive power on the optical axis OA, and can, for example, have negative refractive power. The sixth lens 106 can include a plastic material or a glass material, and can, for example, be a plastic material. The object-side eleventh surface S11 of the sixth lens 106 can have a concave shape on the optical axis OA, and the sensor-side twelfth surface S12 can have a convex shape on the optical axis OA. In other words, the sixth lens 106 can have a meniscus shape that convexes from the optical axis OA toward the sensor side. Alternatively, the eleventh surface S11 can have a convex shape on the optical axis OA, and the twelfth surface S12 can have a convex shape on the optical axis OA. In other words, the sixth lens 106 can have a shape that convexes on both sides on the optical axis OA. Alternatively, the eleventh surface S11 can have a concave shape on the optical axis OA, and the twelfth surface S12 can have a concave shape on the optical axis OA. At least one or both of the eleventh surface S11 and the twelfth surface S12 of the sixth lens 106 may be aspherical, and the eleventh surface S11 and the twelfth surface S12 may be arranged to have no critical point from the optical axis to the end of the effective area.

[0087] The seventh lens 107 can have a positive (+) refractive power or a negative (-) refractive power on the optical axis OA, and can have a negative refractive power. The seventh lens 107 can have a refractive power on the optical axis OA that is opposite to the refractive power of the fourth lens 104 and the fifth lens 105, thereby improving chromatic aberration. The seventh lens 107 can include a plastic material or a glass material, and can be made of a plastic material, for example. The object-side thirteenth surface S13 of the seventh lens 107 can have a convex shape on the optical axis OA, and the sensor-side fourteenth surface S14 can have a concave shape on the optical axis OA. In other words, the seventh lens 107 can have a meniscus shape that is convex toward the object side on the optical axis OA. As another example, the thirteenth surface S13 can have a convex shape on the optical axis OA, and the fourteenth surface S14 can have a convex shape on the optical axis OA. In other words, the seventh lens 107 can have a shape that is convex 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 107 may have a meniscus shape that convexly projects 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 107 may have a shape that is concave on both sides on the optical axis OA. The thirteenth surface S13 and the fourteenth surface S14 of the seventh lens 107 may be arranged so that there is no critical point from the optical axis to the end of the effective area.

[0088] The fifth lens 105 and the sixth lens 106 can adjust chromatic aberration by setting the Abbe number difference to be less than 10. Therefore, the second lens group G2 and the third lens group G3 can minimize chromatic aberration change caused by a position changed according to a mode change and perform an achromatic effect.

[0089] At least one of the object-side thirteenth surface S13 and the sensor-side fourteenth surface S14 of the seventh lens 107 may have a critical point. For example, the fourteenth surface S14 may be provided without a critical point, while the thirteenth surface S13 may have a critical point. A critical point is a point where the slope value changes from positive (+) to negative (-), or from negative (-) to positive (+), with respect to the sign of the optical axis OA and the direction perpendicular to the optical axis OA. This point may represent a point where the slope value is zero. Alternatively, a critical point may be a point where the slope value of a tangent line passing through the lens surface increases and then decreases, or decreases and then increases.

[0090] The difference between the center thickness CT5 and the edge thickness ET5 of the fifth lens 105 may be greater than 0.9. The difference between the center thickness CT6 and the edge thickness ET6 of the sixth lens 106 may be greater than 0.9. The center thicknesses CT5 and CT6 of the fifth and sixth lenses 105 and 106 may be thicker than the center thicknesses of the other lenses and may have the thickest thicknesses. The center thickness CT3 of the third lens 103 may have the thinnest center thickness among the lenses. The center thickness CT2 of the second lens 102 may have the second thinnest center thickness among the lenses. The center thickness CT7 of the seventh lens 107 may be thinner than the edge thickness ET7. Therefore, due to the difference between the center thickness and the edge thickness of the seventh lens 107, uniform light distribution can be provided to the periphery of the image sensor 300.

[0091] Among the multiple lens groups G1, G2, and G3, the third lens group G3 may be closest to the image sensor 300. The third lens group G3 may be movable in the optical axis direction, and due to the change in the optical axis distance (BFL) between the seventh lens 107 and the image sensor 300, the focus position may be adjusted according to the operation mode. The third lens group G3 may play a role in controlling the chief ray angle (CRA). Specifically, the CRA of the optical system 1000 according to an embodiment may be less than about 15 degrees, and the seventh lens 107 of the third lens group G3 may correct the chief ray angle (CRA) of light incident on the image sensor 300 according to each operation mode.

[0092] The camera module according to the first embodiment of the present invention may include the above-mentioned optical system 1000. The camera module may move the second lens group G2 and the third lens group G3 among the multiple lens groups G1, G2 and G3 included in the optical system 1000 in the direction of the optical axis OA. The camera module may include a driving member (not shown) connected to the optical system 1000. The driving member is arranged outside the second lens group G2 and outside the third lens group G3, and may move in the direction of the optical axis OA according to the operating mode. The operating mode may include a first mode that moves at a first magnification and a third mode that operates at a second magnification different from the first magnification. In this case, the second magnification may be greater than the first magnification. In addition, the operating mode may include a second mode having a magnification between the first mode and the third mode. Here, the first magnification may be the lowest magnification of the optical system 1000, and the second magnification may be the highest magnification of the optical system 1000. Between the first magnification and the second magnification, the first magnification may be a magnification of about 2.5 to about 5, the second magnification may be a magnification of about 6 to about 11, and the third magnification may be a magnification of about 4 to about 6. The first mode may be a wide-angle mode, the second mode may be a medium-focus mode, and the third mode may be a telephoto mode. The driving member may move the second lens group G2 and the third lens group G3, or operate them in an initial mode according to one operating mode selected from the first to third modes.

[0093] Specifically, each of the plurality of driving members is connected to the second lens group G2 or the third lens group G3, and can move the second lens group G2 or the third lens group G3 according to the operating mode. The initial mode can be any one of the first mode, the second mode and the third mode, for example, the second mode or the mid-focus mode. For example, in the first mode, each of the second lens group G2 and the third lens group G3 can be located at a position defined as a first position (position 1). In the second mode, each of the second lens group G2 and the third lens group G3 can be located at a second position (position 2) defined as closer to the object than the first position. In the third mode, each of the second lens group G2 and the third lens group G3 can be located at a third position (position 3) defined as closer to the sensor side than the first position. The first position can be an area between the second position and the third position.

[0094] The first position of the second lens group G2 in the first mode may be a region between the second position and the third position of the second lens group G2 in the second and third modes. The first position of the third lens group G3 in the first mode may be a region between the second position and the third position of the third lens group G3 in the second and third modes.

[0095] According to the first embodiment, the optical system 1000 can be configured such that the second lens group G2 and the third lens group G3 can be movable according to the operating mode, and the first lens group G1 can be arranged in a fixed position. Depending on the operating mode, the second lens group G2 or the third lens group G3 can be movable, and the first lens group G1 can be arranged in a fixed position. Depending on the operating mode, in each of the first position, the second position, and the third position, the first lens group G1, the second lens group G2, and the third lens group G3 can have a set distance from the adjacent lens group. Therefore, the optical system 1000 can have a constant total lens length (TTL) and a variable BFL according to the operating mode, and the effective focal length and magnification of the optical system 1000 can be controlled by controlling the positions of some of the lens groups.

[0096] The effective diameter of the first lens 101 is the largest among the lenses, and the effective diameter of the third lens 103 is the smallest among the lenses. The Abbe number of the fourth lens 104 can be the largest among the lenses and can be greater than 70. In terms of the absolute value of the focal length, the focal length of the fifth lens 105 can be the largest among the lenses, and the difference (absolute value) in focal length between two adjacent lenses can be the largest between the fourth and fifth lenses (104 and 105), and the difference between the first and second lenses (101 and 102) can be the smallest. Depending on the operating mode, the optical axis distance DG12 between the first lens group G1 and the second lens group G2, and the optical axis distance DG23 between the second lens group G2 and the third lens group G3 can be greater than 0.2 mm and less than 8 mm. According to the above operating mode, the F-number of the optical system 1000 provides brightness of greater than 2.0, and the F-number can be in the range of 2.2 to 3.8. The aperture can be located between the first lens group G1 and the second lens group G2.

[0097] The optical system 1000 according to the first embodiment can satisfy at least one or more of the mathematical formulas described below. Therefore, the optical system 1000 according to the embodiment can effectively correct aberrations that change depending on the operating mode. Furthermore, the optical system 1000 according to the embodiment can effectively provide autofocus (AF) functionality for an object at various magnifications and can have a slim and compact structure. Hereinafter, the center thicknesses of the first to seventh lenses 101 to 107 can be defined as CT1 to CT7, the edge thicknesses can be defined as ET1 to ET7, and the optical axis distances between adjacent lenses, from the distance between the first and second lenses to the distance between the sixth and seventh lenses, can be defined as CG1 to CG6. The average effective diameters of the object-side and sensor-side surfaces of the first to seventh lenses 101 to 107 can be defined as CA1 to CA7, and the effective diameters of the object-side and sensor-side surfaces of the first lens 101 to the effective diameters of the object-side and sensor-side surfaces of the seventh lens 107 can be defined as CA11 and CA12 to CA71 and CA72. The units of the thickness, distance, and effective diameter values ​​are in mm. In addition, the effective diameter may be defined as a case where the lens is in a circular or partially circular shape, and defined as an effective length or a maximum effective length when the lens is in a partially circular shape.

[0098] [Formula 1] n_G1, n_G2, n_G3, 1 (n_G1, n_G2, n_G3 are natural numbers)

[0099] In Formula 1, n_G1, n_G2, n_G3 represent the number of lenses included in each of the first lens group G1, the second lens group G2, and the third lens group G3. Here, there may be a relationship of n_G1>n_G2 and n_G1<n_G3.

[0100] [Equation 2] 0.7<CA41 / CA11<1.2

[0101] In Formula 2, CA41 is the maximum effective diameter of the seventh surface S7 of the fourth lens 104, and CA11 is the maximum effective diameter of the first surface S1 of the first lens 101. When Formula 2 is satisfied, a higher entrance pupil diameter (EPD) can be provided compared to the optical system.

[0102] [Formula 3] 2<CT1 / CT3<5

[0103] In Formula 3, CT1 is the thickness (mm) of the first lens 101 along the optical axis, and CT3 is the thickness (mm) of the third lens 103 along the optical axis. If Formula 3 is satisfied, the aberration characteristics of the optical system 1000 can be improved. Preferably, 2.5<CT1 / CT3<4 can be satisfied.

[0104] [Formula 4] 0<CT1 / CT4<1.5

[0105] In Formula 4, CT3 represents the thickness (mm) of the fourth lens 104 along the optical axis OA. If the optical system 1000 according to the embodiment satisfies Formula 4, the optical system 1000 can improve aberration characteristics. Preferably, 0.5<CT1 / CT4<1 can be satisfied.

[0106] [Formula 5]0<ET3 / CT3<1

[0107] In Equation 4, ET3 represents the thickness (mm) in the optical axis OA direction at the edge, which is the end of the effective area of ​​the third lens 103. When the optical system 1000 according to the embodiment satisfies Equation 5, the optical system 1000 can improve distortion characteristics. Preferably, 0.3 < ET3 / CT3 < 0.7 can be satisfied.

[0108] [Formula 6] G1F<0

[0109] In Formula 6, G1F is the effective focal length (EFL) of the first lens group G1 and may have a value less than 0. It is the composite focal length of the first to third lenses. When Formula 6 is satisfied, optical aberrations of the optical system or the first lens group G1 may be improved.

[0110] [Formula 7] CRA<20 degrees

[0111] In Formula 7, CRA (chief ray angle) is the chief ray incident angle, and in the optical system, according to the first mode, the second mode, and the third mode, the incident angle of the chief ray may be 20 degrees or less, and may be 15 degrees or less. The first mode may be a wide-angle mode, the second mode may be a mid-focus mode, and the third mode may be a telephoto mode. Here, in the case of the first mode (wide-angle mode), in a field of 1.0, the chief ray incident angle may be greater than the chief ray incident angle in the case of the second mode. In the case of the third mode (telephoto mode), in a field of 1.0, the chief ray incident angle may be 11 degrees or less, and the chief ray incident angle of the second mode may be less than the chief ray incident angle of the first mode. When Formula 6 is satisfied, the peripheral illumination ratio can be ensured.

[0112] [Equation 8] 3.5<(TTL / DG1)

[0113] In Equation 8, DG1 is the optical axis distance of the first lens group G1, for example, the optical axis distance from the center of the object-side surface of the first lens 101 to the center of the sensor-side surface of the third lens 103. For example, DG1 represents the distance (mm) from the first surface S1 of the first lens 101 to the sixth surface S6 of the third lens 103 on the optical axis OA. TTL (Total Track Length) represents the distance (mm) from the object-side first surface S1 of the first lens 101 to the imaging surface of the image sensor 300 on the optical axis OA. When the optical system 1000 according to an embodiment satisfies Equation 8, the optical system 1000 has a relatively small TTL and can ensure a secure peripheral illumination ratio. Preferably, 4 < (TTL / DG1) < 6 can be satisfied.

[0114] [Formula 9]2<TTL / EPD3<7

[0115] In Equation 9, EPD3 represents the size of the entrance pupil diameter (EPD) of the optical system 1000 when operating in the third mode (i.e., telephoto mode). When the optical system 1000 according to an embodiment satisfies Equation 9, the optical system 1000 can ensure a bright image when operating in the third mode, and can be the minimum condition for ensuring an F-number of 4 or less in telephoto mode. Preferably, 3 < TTL / EPD3 < 5 can be satisfied.

[0116] [Formula 9-1] 3<TTL / EPD1<7

[0117] [Formula 9-2] 2<TTL / EPD2<6

[0118] [Equation 9-3] (TTL / EPD3)<(TTL / EPD2)<(TTL / EPD1)

[0119] In equations 9-1 to 9-3, EPD1 is the diameter of the entrance pupil of the optical system in the first mode (wide-angle mode), and EPD2 is the diameter of the entrance pupil of the optical system in the second mode (mid-focus mode). If the optical system meets these conditions, it can ensure a bright image in each mode.

[0120] [Equation 10] 2<CT_Max / CT_Min<6

[0121] In Formula 10, CT_Max is the thickest thickness among the center thicknesses of the lens, and CT_Min is the thinnest thickness among the center thicknesses of the lens, and the aberration characteristics of the optical system can be improved if Formula 10 is satisfied. Preferably, 3<CT_Max / CT_Min<5.5 can be satisfied.

[0122] [Equation 11] 1<CA_Max / CA_Min<3

[0123] In Formula 11, CA_Max is the maximum effective diameter in the lens, and CA_Min is the minimum effective diameter in the lens. If Formula 11 is satisfied, the optical performance of the optical system can be maintained, and a camera module with a light, thin or compact structure can be provided.

[0124] [Formula 12] 0.1<∑CG_Wide / TTL<0.6

[0125] In Equation 12, ∑CG_Wide is the sum of the center distances between adjacent lenses in the first mode. If the optical system satisfies Equation 12, the center distance DG12 between the first and second lens groups, as well as the center distance between the second and third lens groups, can be set according to the wide-angle mode. The center distance DG12 between the first and second lens groups can be the center distance CG3 between the third lens 103 and the fourth lens 104, and can vary depending on the operating mode. The center distance DG23 between the second and third lens groups can be the center distance CG5 between the fifth lens 105 and the sixth lens 106, and can vary depending on the operating mode.

[0126] [Equation 12-1] 0.05<∑CG_Mid / TTL<0.4

[0127] [Formula 12-2]0<∑CG_Tele / TTL<0.3

[0128] In Equations 12-1 and 12-2, ∑CG_Mid is the sum of the center distances between adjacent lenses in the second mode, and ∑CG_Tale is the sum of the center distances between adjacent lenses in the third mode. If the optical system satisfies Equations 12-1 and 12-2, the center distance DG12 between the first lens group and the second lens group, as well as the center distance between the second lens group and the third lens group, can be set according to the mid-focus mode and the telephoto mode. If the optical system 1000 according to the first embodiment satisfies at least one or two of Equations 1 to 12, the optical system 1000 can have a lightweight and thin structure. In addition, the optical system 1000 can have improved assemblability and a mechanically stable shape.

[0129] [Equation 13] 0.5<DG1 / DG2<3

[0130] In Equation 13, DG1 is the optical axis distance of the first lens group G1, and for example, represents the optical axis distance between the first surface S1 of the first lens 101 and the sixth surface S6 of the third lens 103. DG2 is the optical axis distance of the second lens group G2, for example, the optical axis distance between the seventh surface S7 of the fourth lens 104 and the tenth surface S10 of the fifth lens 105. In Equation 13, the TTL can be adjusted by setting the optical axis distance between the first lens group G1 and the second lens group G2. Preferably, 0.5 < DG1 / DG2 < 1 can be satisfied.

[0131] [Equation 14] 0.5<DG2 / DG3<2

[0132] In Equation 14, DG2 represents the optical axis distance of the second lens group G2, for example, the optical axis distance between the seventh surface S7 of the fourth lens 104 and the tenth surface S6 of the fifth lens 105. DG3 represents the optical axis distance of the third lens group G3, for example, the optical axis distance between the eleventh surface S11 of the sixth lens 106 and the fourteenth surface S14 of the seventh lens 107. Preferably, 0.8 < DG2 / DG3 < 1.5 can be satisfied. When the optical system 1000 according to an embodiment satisfies at least one of Equations 13 and 14, it has a relatively small TTL and can provide various magnifications according to at least three mode changes.

[0133] [Equation 15] 0<CG2 / TTL<0.2

[0134] In Equation 15, CG2 is the optical axis distance between the second lens 102 and the third lens 103. When the optical system 1000 satisfies Equation 15, the optical system 1000 has a relatively small TTL and can have improved optical characteristics by controlling stray light incident on the first lens group G1. Preferably, 0 < CG2 / TTL < 0.1 can be satisfied.

[0135] [Equation 16] 3<TTL / DG2<10

[0136] In Formula 16, DG2 is the optical axis distance of the second lens group G2. When the optical system 1000 according to the embodiment satisfies Formula 16, the optical system 1000 has a relatively small TTL and can improve chromatic aberration characteristics.

[0137] [Equation 17] 20<|Vd4-Vd5|<70

[0138] In Formula 17, Vd4 represents the Abbe number of the fourth lens 104, and Vd5 represents the Abbe number of the fifth lens 105. If the absolute value of the Abbe number difference between the fourth lens and the fifth lens of the optical system 1000 according to the embodiment satisfies Formula 17, the optical system 1000 can improve chromatic aberration characteristics.

[0139] [Equation 18] 15<|Vd7-Vd6|<60

[0140] In Formula 18, Vd7 represents the Abbe number of the seventh lens, and Vd6 represents the Abbe number of the sixth lens. If the absolute value of the Abbe number difference between the sixth lens and the seventh lens satisfies Formula 18, the optical system 1000 can improve chromatic aberration characteristics.

[0141] [Equation 19] 1.6<n2

[0142] In Equation 19, n2 represents the d-line refractive index of second lens 102. When optical system 1000 according to an embodiment satisfies Equation 19, incident light can be dispersed and the effective area of ​​the lenses arranged after second lens 102 can be ensured. The refractive indices of fourth lens 104 and seventh lens 107 can be less than 1.6, and the refractive index of fourth lens 104 can be the smallest among the lenses. The number of lenses having a refractive index of 1.63 or greater is two or more.

[0143] [Equation 20] 1<L1R1 / L3R2<2.5

[0144] In Equation 20, L1R1 represents the curvature radius of the object-side first surface S1 of the first lens 101, and L3R2 represents the curvature radius of the sensor-side sixth surface S6 of the third lens 103. When the optical system 1000 according to an embodiment satisfies Equation 20, the optical system 1000 can control stray light incident on the first lens group G1.

[0145] [Equation 21] 1.5<L1R1 / L4R1<3.5

[0146] In Formula 21, L1R1 represents the curvature radius of the object-side first surface S1 of the first lens 101, and L4R1 represents the curvature radius of the object-side seventh surface S7 of the fourth lens 104. When the optical system 1000 according to an embodiment satisfies Formula 21, the optical system 1000 can have good optical performance at various magnifications.

[0147] [Equation 22] 0<L3R2 / L4R1<2

[0148] In Equation 22, L3R2 represents the radius of curvature of the sensor-side sixth surface S6 of the third lens 103, and L4R1 represents the radius of curvature of the object-side seventh surface S7 of the fourth lens 104. When the optical system 1000 according to the embodiment satisfies Equation 22, the optical system 1000 can have good optical performance in the peripheral portion of the field of view (FOV) when operating at various magnifications in at least three modes.

[0149] [Equation 23] 1<L1R1 / L7R2<3

[0150] In Equation 23, L1R1 represents the curvature radius of the object-side first surface S1 of the first lens 101, and L7R2 represents the curvature radius of the sensor-side fourteenth surface S14 of the seventh lens 107. When the optical system 1000 according to an embodiment satisfies Equation 23, the optical system 1000 can have good optical performance in the central portion and the peripheral portion of the field of view (FOV).

[0151] [Equation 24] 0<Mode12_mG2 / TTL<0.5

[0152] In Formula 24, Mode12_mG2 represents the difference in the center distance (unit: mm) after the movement of the second lens group G2 when changing from the second mode to the first mode or from the first mode to the second mode. Specifically, Mode12_mG2 represents the movement distance of the second lens group G2 in the first mode and the second mode, and represents the difference between the optical axis distance between the first lens group G1 and the second lens group G2 in the first mode and the optical axis distance between the first lens group G1 and the second lens group G2 in the second mode. When the optical system 1000 according to the embodiment satisfies Formula 24, the optical system 1000 can minimize the movement distance of the second lens group G2 when the magnification changes, so that the optical system 1000 can have a light and thin structure. In addition, when the position of the second lens group G2 is controlled, the movement distance can be minimized, thereby achieving improved power consumption characteristics.

[0153] [Equation 25] 0<Mode23_mG2 / TTL<0.5

[0154] In Formula 25, Mode23_mG2 represents the difference (unit: mm) in the center distance after the movement of the second lens group G2 when operating from the second mode to the third mode or from the third mode to the second mode. Specifically, Mode23_mG2 represents the difference between the optical axis distance between the first lens group G1 and the second lens group G2 in the second mode and the optical axis distance between the first lens group G1 and the second lens group G2 in the third mode. The maximum movement distance of the second lens group G2 can be greater than the maximum movement distance of the third lens group G3. When the optical system 1000 according to the embodiment satisfies Formula 25, the optical system 1000 can minimize the movement distance of the second lens group G2 when the magnification changes, so that the optical system 1000 can have a light and thin structure. In addition, when the position of the second lens group G2 is controlled, the movement distance can be minimized, so that it can have improved power consumption characteristics.

[0155] [Equation 26] 0.3<Mode12_mG2 / DG2<1

[0156] Formula 26 represents the difference in center distance after the movement of the second lens group G2 when Mode12_mG2 operates from the first mode to the second mode or from the second mode to the first mode (unit: mm). When the optical system 1000 according to the embodiment satisfies Formula 26, the optical system 1000 can minimize the movement distance of the second lens group G2 when the magnification changes, so that the optical system 1000 can have a light and thin structure. In addition, when the position of the second lens group G2 is controlled, the movement distance can be minimized, so that the optical system 1000 can have improved power consumption characteristics. DG2 is the optical axis distance of the second lens group G2. When the optical system 1000 according to the embodiment satisfies Formula 26, the optical system 1000 can minimize the movement distance of the second lens group G2 when the magnification changes, so that the optical system 1000 can have a light and thin structure. In addition, when the position of the second lens group G2 is controlled, the movement distance can be minimized, so that the optical system 1000 can have improved power consumption characteristics.

[0157] [Equation 27] 0<Mode23_mG3 / DG3<0.5

[0158] In Equation 27, Mode23_mG3 represents the difference in center distance after movement of the third lens group G3 when changing from the second mode to the third mode or vice versa. DG3 is the optical axis distance of the third lens group G3. When the optical system 1000 according to an embodiment satisfies Equation 27, the movement distance of the third lens group G3 can be minimized when the magnification is changed, allowing the optical system 1000 to have a thin and lightweight structure. In addition, since the movement distance can be minimized when controlling the position of the third lens group G3, it can have improved power consumption characteristics.

[0159] [Formula 28]0<(CT1 / ET1) / (CT3 / ET3)<1

[0160] In Formula 28, CT1 / ET1 is the value obtained by dividing the thickness of the first lens 101 along the optical axis by the thickness at the end, and CT3 / ET3 is the value obtained by dividing the thickness of the third lens 103 along the optical axis by the thickness at the end. If the values ​​obtained by dividing the center thickness of the first lens 101 and the third lens 103 by the end thickness satisfy Formula 28 under the above ratio, chromatic aberration can be improved and incident light can be controlled.

[0161] [Equation 29] 0.5<(CT1 / ET1) / (CT7 / ET7)<1.5

[0162] In Formula 29, CT1 / ET1 is a value obtained by dividing the thickness of the seventh lens 107 along the optical axis by the thickness at the end. If the value obtained by dividing the center thickness of the first lens 101 and the seventh lens 107 by the thickness at the end satisfies Formula 29 with the above ratio, chromatic aberration can be improved and incident light can be controlled.

[0163] [Equation 30] 1<Mode1(DG12 / DG23)<5

[0164] In Equation 30, Mode1(DG12 / DG23) represents the ratio of the center distance DG12 between the first lens group and the second lens group to the center distance DG23 between the second lens group and the third lens group in the first mode. If the optical system 1000 according to an embodiment satisfies Equation 30, the optical system 1000 can have improved optical characteristics at the first magnification. Specifically, the optical system 1000 can have improved aberration characteristics at the first magnification, and can improve optical performance in the central and peripheral portions of the FOV.

[0165] [Equation 31] 0<Mode3(DG12 / DG23)<0.7

[0166] In Equation 31, Mode3(DG12 / DG23) represents the ratio of the center distance DG12 between the first lens group and the second lens group to the center distance DG23 between the second lens group and the third lens group in the third mode. When the optical system 1000 according to an embodiment satisfies Equation 31, the optical system 1000 can have improved optical characteristics at the second magnification. Specifically, the optical system 1000 can have improved aberration characteristics at the second magnification, and can improve optical performance in the peripheral portion of the FOV.

[0167] [Equation 32] 0.5<TD2 / TTL<1

[0168] In Equation 32, TD2 is the optical axis distance from the center of the object-side surface of the first lens element to the center of the sensor-side surface of the seventh lens element in the second mode. When the optical system 1000 according to an embodiment satisfies Equation 32, the optical system 1000 can have improved optical characteristics in the mid-focus mode. Specifically, the optical system 1000 can have improved aberration characteristics in the mid-focus mode and can improve optical performance in the peripheral portion of the field of view (FOV).

[0169] [Equation 33] 0.7<TD1 / TD2<1.5

[0170] In Equation 33, TD1 is the optical axis distance from the center of the object-side surface of the first lens to the center of the sensor-side surface of the seventh lens in the first mode. When the optical system 1000 according to an embodiment satisfies Equation 33, the optical system 1000 can have improved optical characteristics in both the first and second modes. Specifically, the optical system 1000 can have improved aberration characteristics in both the first and second modes, and can improve optical performance in the peripheral portion of the FOV.

[0171] [Equation 34] 12 mm < TD3 < TD2 < TD1 < 20 mm

[0172] Equation 34 compares the optical axis distances of the lenses in the first, second, and third modes, and TD3 is the optical axis distance from the center of the object-side surface of the first lens to the center of the sensor-side surface of the seventh lens in the third mode. When the optical system 1000 according to an embodiment satisfies Equation 34, the optical system 1000 can exhibit improved optical characteristics in the first, second, and third modes. Specifically, the optical system 1000 can exhibit improved aberration characteristics in the first, second, and third modes, and improve optical performance in the peripheral portion of the field of view (FOV).

[0173] [Equation 35] 0.1<BFL2 / TTL<1

[0174] In Equation 35, BFL2 (Back Focus 2) is the optical axis distance from the center of the sensor-side surface of the seventh lens element to the imaging surface of the image sensor in the second mode. When the optical system 1000 according to an embodiment satisfies Equation 35, the optical system 1000 can adjust the focus position toward the imaging surface of the image sensor 300 in the second mode. Specifically, the optical system 1000 has improved optical characteristics in the second mode and can improve the optical performance of the peripheral portion of the FOV. Preferably, 0.1 < BFL2 / TTL < 0.5 can be satisfied.

[0175] [Equation 36] 2<BFL3 / BFL1<4

[0176] In Equation 36, BFL3 is the optical axis distance from the center of the sensor-side surface of the seventh lens to the imaging surface of the image sensor in the third mode. When the optical system 1000 according to an embodiment satisfies Equation 36, the optical system 1000 can adjust the focus position toward the imaging surface of the image sensor 300 in both the first and third modes. Specifically, the optical system 1000 exhibits improved optical characteristics in both the first and third modes, and can improve optical performance in the peripheral portion of the field of view (FOV). Preferably, 2 < BFL3 / BFL1 < 3.3 can be satisfied.

[0177] [Equation 37] 1.5<TD3 / BFL3<3

[0178] Equation 37 compares the optical axis distance (TD3) between the center of the object-side surface of the first lens and the center of the sensor-side surface of the seventh lens in the third mode, and the optical axis distance (BFL3) from the center of the sensor-side surface of the seventh lens 107 to the imaging surface of the image sensor. When the optical system 1000 according to an embodiment satisfies Equation 37, the optical system 1000 can have improved optical characteristics in the third mode. Specifically, the optical system 1000 can have improved aberration characteristics in the third mode and can improve optical performance in the peripheral portion of the FOV.

[0179] [Formula 38] 2<Mode_CG_Max / Mode_CG_Min<8

[0180] In Equation 38, Mode_CG_Max represents the maximum center distance among the center distances between the first lens to the seventh lens in the first, second, and third modes, and Mode_CG_Min represents the minimum center distance among the center distances between the first lens to the seventh lens in the first, second, and third modes. When the optical system satisfies Equation 38, the TTL and optical axis distance of the lenses according to each mode can be adjusted.

[0181] [Formula 39]1<BFL1<5

[0182] Equation 39 represents the optical axis distance between the seventh lens and the image sensor in the first mode. When the optical system satisfies Equation 39, the focus position on the imaging surface of the image sensor in the first mode can be adjusted.

[0183] [Equation 40] 30<Aver_Abbe<50

[0184] In Formula 40, Aver_Abbe is an average value of Abbe numbers of the first to seventh lenses. When the optical system satisfies Formula 40, the optical system 1000 may have improved aberration characteristics and resolution.

[0185] [Equation 41] 1.5<Aver_Index<1.8

[0186] In Equation 40, Aver_Index is an average value of the refractive indices of the first to seventh lenses. When the optical system satisfies Equation 41, the optical system 1000 may have improved aberration characteristics and resolution.

[0187] [Equation 41-1] 10<∑Abbe / ∑Index<40

[0188] In Formula 41-1, ∑Abbe represents the sum of the Abbe numbers of each of the multiple lenses. ∑Index represents the sum of the refractive indices of each of the multiple lenses. When the optical system 1000 according to the embodiment satisfies Formula 41-1, the optical system 1000 can have improved aberration characteristics and resolution. Preferably, Formula 41-1 can satisfy 20<∑Abbe / ∑Index<35. Preferably, the condition of (∑Abb-∑Index)<300 can be satisfied.

[0189] [Equation 42] 2<|G1F / G2F|<4

[0190] In Equation 42, G1F represents the effective focal length (EFL) of the first lens group G1, and G2F represents the effective focal length of the second lens group G2. G2F is the combined focal length of the fourth and fifth lenses. When Equation 42 is satisfied, the size of the optical system can be reduced, for example, in a TTL configuration. Preferably, G2F > 0. G3F is the combined focal length of the sixth and seventh lenses, and G3F < 0, and the condition |G1F| > |G3F| > G2F can be satisfied.

[0191] [Equation 43] 1<M2F / M1F<10

[0192] In equation 43, M1F is the effective focal length of the optical system in the first mode, and M2F is the effective focal length of the optical system in the second mode. Preferably, 1<M2F / M1F<3 can be satisfied. When the optical system satisfies equation 43, the effective focal length can be adjusted according to the first mode and the second mode.

[0193] [Formula 43-1] 1<M3F / M2F<10

[0194] In Equation 43, M3F is the effective focal length of the optical system in the third mode. Preferably, 1 < M3F / M2F < 3, and (M3F / M1F) > (M3F / M2F) can be satisfied. When the optical system satisfies Equation 43-1, the effective focal length can be adjusted according to the second and third modes.

[0195] [Equation 44] 2<M2F / EPD2<7

[0196] In Formula 44, M2F is the effective focal length of the optical system in the second mode (mid-focus mode), and EPD2 represents the size of the EPD of the optical system 1000 in the second mode. When the optical system 1000 according to the embodiment satisfies Formula 44, the optical system 1000 can ensure a bright image when operating in the second mode.

[0197] [Equation 45] 0.1<M1F / EPD1<3

[0198] In Equation 34, M1F is the effective focal length of the optical system in the first mode (wide-angle mode), and EPD1 represents the size of the EPD when the optical system 1000 operates in the first mode. When the optical system 1000 according to the embodiment satisfies Equation 45, the optical system 1000 can ensure a bright image when operating in the first mode.

[0199] [Equation 46] M1F<M2F<M3F

[0200] In Equation 46, M1F, M2F, and M3F represent effective focal lengths of the optical system in the first mode, the second mode, and the third mode. The effective focal length in the third mode may be the largest, and the effective focal length in the first mode may be the smallest.

[0201] [Equation 47] 0<TTL / M2F<2

[0202] Equation 47 can adjust TTL by comparing the effective focal length in TTL and the second mode. Preferably, 1<TTL / M2F<2 can be satisfied.

[0203] [Equation 48] 0.1<TTL / M1F<5

[0204] The TTL can be adjusted by comparing the TTL with the effective focal length in the first mode according to Equation 47. Preferably, 1<TTL / M1F<4 can be satisfied.

[0205] [Equation 49] 1<CA_Max / ImgH<3

[0206] In Equation 49, CA_Max represents the size of the maximum effective diameter (CA) in the lens surface of the lens unit 100 included in the optical system 1000. ImgH is the distance from the 0 field area of ​​the image sensor 300 overlapping with the optical axis OA to the 1.0 field area of ​​the image sensor 300. ImgH represents 1 / 2 of the diagonal length of the effective area of ​​the image sensor 300. When the optical system 1000 according to the embodiment satisfies Equation 49, the optical system 1000 can be provided in a light, thin and compact manner. In addition, the optical system 1000 can achieve high resolution and high image quality. The range of ImgH is in the range of 2 mm to 3 mm.

[0207] [Equation 50] 5<TTL / ImgH<12

[0208] When the optical system 1000 satisfies the formula 39, the optical system 1000 can have a smaller TTL, so the optical system 1000 can be provided in a light, thin and compact manner. Preferably, it can be in the range of 6<TTL / ImgH<10.

[0209] [Formula 51] 1<BFL2 / ImgH<3

[0210] If the optical system 1000 according to an embodiment satisfies Equation 51, it can ensure the BFL required for small image sensors smaller than 1 inch. Furthermore, if the optical system 1000 satisfies Equation 51, it can operate at various magnifications while maintaining TTL and can exhibit excellent optical characteristics in both the central and peripheral portions of the FOV. Preferably, it can be within the range of 2 < BFL2 / ImgH < 3.

[0211] [Formula 52] 2<BFL3 / ImgH<4

[0212] If the optical system 1000 according to an embodiment satisfies Equation 52, it can ensure the BFL required for small image sensors smaller than 1 inch. Furthermore, when the optical system 1000 satisfies Equation 51, it can operate at various magnifications while maintaining TTL and exhibit excellent optical characteristics in both the central and peripheral portions of the FOV. Preferably, 2.5 < BFL3 / ImgH < 3.5 can be satisfied.

[0213] [Equation 53] 1<EPD1<EPD2<EPD3<7

[0214] In Equation 53, EPD1, EPD2, and EPD3 represent the sizes of EPDs of the optical system according to the first to third modes, and the brightness can be adjusted according to the respective modes.

[0215] [Formula 54]0<Max_Distortion<3

[0216] In Equation 54, Distortion represents the maximum value or maximum value of distortion from the center (0.0F) to the diagonal end (1.0F) of the image sensor based on the optical characteristics detected by image sensor 300. When optical system 1000 satisfies Equation 54, optical system 1000 can improve distortion characteristics and set conditions for image processing. Preferably, Distortion < 1.5 can be satisfied.

[0217] [Equation 55] 8<FOV3<FOV2<FOV1<45

[0218] In Equation 55, FOV1, FOV2, and FOV3 represent the diagonal fields of view of the optical system in the first, second, and third modes. FOV represents the diagonal field of view (degrees) of the optical system 1000, and an optical system of less than 45 degrees may be provided.

[0219] The aspheric coefficients of the second embodiment will refer to Equation 56 of the first embodiment.

[0220] [Equation 56]

[0221]

[0222] In Equation 56, Z may represent Sag, which may represent the distance from any position on the aspherical surface to the vertex of the aspherical surface in the direction of the optical axis. Additionally, Y may represent the distance from any position on the aspherical surface to the optical axis in a direction perpendicular to the optical axis. Additionally, c may represent the curvature of the lens, and K may represent a conic constant. Additionally, A, B, C, D, E, and F may represent aspheric constants.

[0223] The optical system 1000 according to the first embodiment can satisfy at least one or more of the above-mentioned formulas 1 to 55. Therefore, the optical system 1000 and the camera module can have improved optical characteristics. Specifically, when the optical system 1000 satisfies at least one or more of the above-mentioned formulas, the camera module can effectively correct the degradation of optical characteristics caused by the movement of the lens group, such as chromatic aberration, vignetting, diffraction effects, and degradation of peripheral image quality. In addition, the optical system 1000 according to the first embodiment can significantly reduce the moving distance of the lens group and provide an autofocus (AF) function for each magnification with excellent power consumption characteristics. The camera module according to the first embodiment has improved assembly performance due to the optical system 1000 satisfying at least one or two of the above-mentioned formulas 1 to 55, and can have a mechanically stable form and can be provided with a thin and light structure, so that the optical system 1000 and the camera module including it can have a compact structure.

[0224] Hereinafter, the optical system 1000 according to the first embodiment and the change from the first mode to the third mode will be described in more detail. In the optical system 1000 according to the embodiment, the first lens group G1 can be fixed, and the second lens group G2 and the third lens group G3 can be moved according to the operation mode. The first lens group G1 can include three lenses, for example, a first lens 101, a second lens 102, and a third lens 103, and the second lens group G2 can include two lenses, for example, a fourth lens 104 and a fifth lens 105. In addition, the third lens group G3 can include two lenses, for example, a sixth lens 106 and a seventh lens 107. The object-side surface (seventh surface S7) of the fourth lens 104 can be used as an aperture stop, and the above-mentioned optical filter 500 can be arranged between the fourth lens group G4 and the image sensor 300.

[0225] Figure 4 The curvature radius of the first lens 101 to the seventh lens 107 on the optical axis OA, the center thickness (CT) of the lens, the center distance (CG) between adjacent components (for example, lenses), the refractive index at the d line (Refractive index), the Abbe number and the effective diameter (CA) are shown. Figure 4 , the object-side surfaces and sensor-side surfaces of the first to seventh lenses (lenses 1 to 7) are depicted as S1 and S2, DG12 is the optical axis distance between the third lens 103 and the fourth lens 104, and DG23 represents the optical axis distance between the fifth lens 105 and the sixth lens 106. DG4 is the optical axis distance between the seventh lens and the optical filter 500, and may vary according to the movement of the third lens group G3.

[0226] [Table 1]

[0227]

[0228] Referring to Table 1, the ratio (CT / ET) of the center thickness (CT) to the edge thickness (ET) of each lens of the lens unit 100 may be different from each other, and the CT / ET value of the fourth lens 104 may be the largest, and the CT / ET value of the third lens may be the smallest. The number of lenses having a CT / ET value less than 1 may be 4 or less, and may include the second lens, the fifth lens, the sixth lens, and the seventh lens, and the number of lenses having a CT / ET value greater than 2 may be 1, and may include the fourth lens. Figure 1 and Figure 2 As shown, the Abbe number Vd4 of the fourth lens 104 included in the second lens group G2 may be higher than the Abbe number Vd5 of the fifth lens 105 by 30 or more or 40 or more. Since the fourth lens 104 and the fifth lens 105 have the above-mentioned difference in Abbe number, the change in chromatic aberration that occurs when the magnification changes according to the movement M1 of the second lens group G2 can be minimized. Figure 1 and Figure 3 As shown, the Abbe number Vd7 of the seventh lens 107 included in the third lens group G3 may be higher than the Abbe number Vd6 of the sixth lens 106 by 20 or more or 30 or more. Since the sixth lens 106 and the seventh lens 107 have the above-mentioned difference in Abbe number, a change in chromatic aberration occurring when magnification changes according to the movement M2 of the third lens group G3 may be minimized and / or compensated, thereby performing an achromatic function.

[0229] The camera module according to the first embodiment can obtain information about an object at various magnifications. Specifically, the driving member can control the position of the second lens group G2 and the position of the third lens group G3, so that the camera module can operate at various magnifications. For example, referring to Figure 1 、 Figure 6 and Figure 9 , the camera module including the optical system 1000 can operate in a first mode having a first magnification. The first magnification can be about 3 times to about 5 times. Specifically, in an embodiment, the first magnification can be about 3.5 times.

[0230] In the first mode, each of the second lens group G2 and the third lens group G3 can be moved to a set position. Thus, each of the first to third lens groups G3 can be arranged at a set interval. For example, the second lens group G2 can be located in an area separated from the first lens group G1 by a first interval DG12, and the third lens group G3 can be located in an area separated from the second lens group G2 by a second interval DG23. Here, the first interval DG12 and the second interval DG23 can represent the spacing between the lens groups on the optical axis OA and can vary depending on the operating mode. When the camera module operates in the first mode, the optical system 1000 can have a TTL value and a BFL1 value at the first position. Furthermore, the optical system 1000 can have an M1F defined as a first EFL at the first position. Furthermore, the camera module's FOV in the first mode can be less than approximately 35 degrees, and the F-number can be less than approximately 3.

[0231] When the camera module operates in the second mode, the optical system 1000 may have a TTL value and a BFL2 value at the second position. Furthermore, the optical system 1000 may have an M2F defined as a second EFL at the second position. Furthermore, the camera module's FOV in the second mode may be less than approximately 25 degrees, and its F-number may be less than approximately 3.4. When the camera module operates in the third mode, the optical system 1000 may have a TTL value and a BFL3 value at the third position. Furthermore, the optical system 1000 may have an M3F defined as a third EFL at the third position. Furthermore, the camera module's FOV in the third mode may be less than approximately 20 degrees, and its F-number may be less than approximately 4.

[0232] like Figure 5 As shown in FIG. 1 , the relative illumination (RI) in each mode can be changed according to the height of the image sensor, and it can be seen that the relative illumination at the periphery or edge of the image sensor is above 50%. The optical system 1000 can have the following configuration in the first mode: Figure 6 and Figure 9 Specifically, Figure 6 is a graph of the diffraction MTF characteristics of the optical system 1000 operating in the first mode (first magnification), and Figure 9 This is a graph showing aberration characteristics. The diffraction MTF characteristic curve is measured in units of approximately 0.252 mm over a spatial frequency range of 0.000 mm to 2.2520 mm. In the diffraction MTF curve, T represents the MTF variation per millimeter of spatial frequency in the tangential direction, and R represents the MTF variation per millimeter of spatial frequency in the radial direction. Here, the MTF (Modulation Transfer Function) depends on the spatial frequency per millimeter period.

[0233] exist Figure 9In the aberration graph, spherical aberration (longitudinal spherical aberration), astigmatism field curve and distortion are measured from left to right. Figure 6 In FIG, the X-axis may represent focal length (mm) and distortion (%), and the Y-axis may represent the height of the image. In addition, the graph of spherical aberration is a graph of light in the wavelength bands of about 435 nm, about 486 nm, about 546 nm, about 587 nm, and about 656 nm, and the graph of astigmatism and distortion is a graph of light in the wavelength band of 546 nm. Figure 9 In the aberration diagram, the closer the curves are to the Y-axis, the better the aberration correction function can be explained. Figure 9 , it can be seen that the optical system 1000 according to the embodiment has measurement values ​​close to the Y-axis in almost all areas.

[0234] Table 2 and Figure 3 These are the items in the above-mentioned formula regarding the optical system 1000 of the embodiment, including TTL (mm), back focal length BFL, effective focal length F (mm), ImgH (mm), effective diameter CA (mm), thickness (mm), TD (mm) (optical axis distance from the first surface S1 to the fourteenth surface S14), the focal length F1, F2, F3, F4, F5, F6 and F7 (mm) of each of the first to seventh lenses, the sum of the refractive indices of each lens, the sum of the Abbe numbers of each lens, the sum of the center thicknesses of each lens (mm), the sum of the center distances between adjacent lenses, the effective diameter, diagonal FOV (degrees), edge thickness (ET), the focal lengths of the first lens group and the second lens group, the F number, and the like.

[0235] [Table 2]

[0236]

[0237]

[0238] Table 3 shows the center distance DG12 between the first lens group and the second lens group, the center distance DG23 between the second lens group and the third lens group, the center distance DG4 between the seventh lens and the optical filter, the effective focal length (EFL) according to each mode, the EPD according to each mode, the optical axis distance (TD) of the lenses according to each mode, the F number and the field of view according to each mode, and the BFL according to each mode according to the first mode to the third mode.

[0239] [Table 3]

[0240]

[0241]

[0242] Tables 4 and 5 show the results of the above-mentioned equations 1 to 55 in the optical system 1000 of the embodiment. Specifically, it can be seen that the optical system 1000 according to the embodiment satisfies all equations 1 to 55. Therefore, the optical system 1000 can have good optical performance and excellent optical characteristics in the central part and the peripheral part of the field of view (FOV).

[0243] [Table 4]

[0244]

[0245]

[0246] [Table 5]

[0247]

[0248]

[0249] Will refer to Figures 12 to 22 An optical system and a camera module according to a second embodiment are described. In the description of the second embodiment, the same configurations and descriptions as those of the first embodiment will be referred to the description of the first embodiment.

[0250] Reference Figures 12 to 22 According to the second embodiment, the optical system 1000 may include a plurality of lens groups G1, G2, and G3. The plurality of lens groups G1, G2, and G3 may include a lens group fixed on the object side and a plurality of movable lens groups located on the sensor side. The lens group fixed on the object side may be defined as the first lens group G1, and the movable lens group may be defined as the second lens group G2 on the object side and the third lens group G3 on the sensor side. The second lens group G2 may be arranged between the first lens group G1 and the third lens group G3. The first lens group G1 collects incident light, the second lens group G2 changes the zoom ratio (focal length), and the third lens group G3 may adjust the focus position on the imaging surface of the image sensor 300. The number of lenses in the first lens group G1 may be greater than the number of lenses in the second lens group G2. The number of lenses in the second lens group G2 may be less than the number of lenses in each of the first lens group G1 and the third lens group G3.

[0251] The multiple lenses of the first lens group G1 may include at least three lenses for adjusting the amount of incident light, diopter, and chromatic aberration. The third lens group G3 may include at least two or three lenses. For example, the optical system may further include at least one lens fixed between the third lens group G3 and the image sensor 300. The first lens group G1 may have at least two lenses with opposite diopter powers. For example, the first lens group G1 may include three lenses. The first lens group G1 may have a greater number of lenses with negative diopter powers than lenses with positive diopter powers.

[0252] 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 negative (-) refractive power. The absolute value of the refractive power of the first lens group G1 may be greater than the absolute values ​​of the refractive power of the second lens group G2 and the third lens group G3. For example, the absolute value of the refractive power of the first lens group G1 may be at least twice the absolute value of the refractive power of the second lens group G2. Therefore, the first lens group G1 may disperse incident light. The first lens group G1 and the third lens group G3 may have negative refractive power, and the second lens group G2 may have positive refractive power.

[0253] Since the first lens group G1 and the second lens group G2 have opposite refractive powers, the focal length of the second lens group G2 may have an opposite sign to that of the first lens group G1. The focal length of the second lens group G2 may have a positive (+) sign, and the focal length of the first lens group G1 may have a negative (-) sign. Refractive power is the reciprocal of focal length. As described above, since the second lens group G2 and the third lens group G3 have opposite refractive powers, the focal length of the second lens group G2 may have an opposite sign (+, -) to that of the focal length of the third lens group G3. For example, the focal length of the second lens group G2 may have a positive (+) sign, and the focal length of the third lens group G3 may have a negative (-) sign.

[0254] The absolute value of the focal length of each of the first lens group G1, the second lens group G2, and the third lens group G3 can decrease in the order of the first lens group G1, the third lens group G3, and the second lens group G2. The first lens group G1 is fixed in place, and the second lens group G2 and the third lens group G3 can be moved in the direction of the optical axis OA, so that the optical system can provide various magnifications by moving the lens groups. The multiple lenses included in the first lens group G1 can have a set spacing. Specifically, according to the operating mode described below, the center distance between the multiple lenses included in the first lens group G1 can be a fixed spacing. For example, the center distance between the first lens 111 and the second lens 112 and the center distance between the second lens 112 and the third lens 113 can have a constant spacing and do not change according to the operating mode. Here, the center distance between the lenses can represent the optical axis spacing between adjacent lenses.

[0255] The second lens group G2 may include a plurality of lenses. Specifically, the second lens group G2 may include four or fewer 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 plurality of lenses included in the second lens group G2 may have set intervals. Specifically, the center distances between the plurality of lenses included in the second lens group G2 may be fixed intervals depending on the operating mode described below. For example, the center distance between the fourth lens 114 and the fifth lens 115 may not change depending on the operating mode and may have a constant interval.

[0256] The third lens group G3 may include multiple lenses. Specifically, the third lens group G3 may include two or more lenses with opposite refractive powers. The number of lenses with negative refractive power in the third lens group G3 may be greater than the number of lenses with positive refractive power. The number of lenses in the third lens group G3 may be at least one greater than the number of lenses in the second lens group G2. The number of lenses in the third lens group G3 may be the same as the number of lenses in the first lens group G1. For example, the third lens group G3 may include three lenses. The multiple lenses in the third lens group G3 may have a set spacing. Specifically, even when the operating mode described below changes, the center distances between the multiple lenses in the third lens group G3 may remain constant. For example, the center distances between the sixth lens 116 and the seventh lens 117, and the center distances between the seventh lens 117 and the eighth lens 118 may remain constant regardless of the operating mode. The last lens in the third lens group G3 has a set spacing from the image sensor 300 and / or the optical filter 500, and this spacing may vary depending on the operating mode.

[0257] Optical system 1000 includes a lens unit 100A having lens groups G1, G2, and G3. Lens unit 100A includes a plurality of lenses and, for example, may include first to eighth lenses 111 to 118. First lens group G1 may include first lens 111, second lens 112, and third lens 113, and second lens group G2 may include fourth lens 114 and fifth lens 115. In addition, third lens group G3 may include sixth lens 116, seventh lens 117, and eighth lens 118. First to eighth lenses 111 to 118 and image sensor 300 may be arranged in sequence along optical axis OA of optical system 1000.

[0258] At least one lens of the first lens group G1 may include a non-circular lens. At least one lens of the second lens group G2 may include a non-circular lens. At least one lens of the third lens group G3 may include a non-circular lens. For example, the first lens 111 having the largest diameter among the lenses may have different lengths in the first direction Y and the second direction X. The fourth lens 114 of the second lens group G2 may have different lengths in the first direction Y and the second direction X. The optical system 1000 and the camera module according to the second embodiment can have improved assemblability due to the non-circular lenses and can have a mechanically stable form. In addition, the optical system 1000 can significantly reduce the moving distance of the moving lens group and provide a variety of magnifications.

[0259] The optical system 1000 may include an image sensor 300 and an optical filter 500, and will be described with reference to the first embodiment. An aperture stop can control the amount of light incident on the optical system 1000. The aperture stop can be located on the periphery of the object-side surface of the first lens 111, or can be arranged between two lenses selected from the first to eighth lenses 111, 118. For example, the aperture stop can be arranged on the periphery between the third lens 113 and the fourth lens 114. The aperture stop can be arranged on the periphery of the sensor-side surface of the third lens 113 or on the periphery of the object-side surface of the fourth lens 114. Alternatively, at least one of the first to eighth lenses 111, 118 can function as the aperture stop. For example, the outer surface of the object-side surface or the sensor-side surface of one of the first to eighth lenses 111, 118 can function as the aperture stop for controlling the amount of light. For example, at least one of the sensor-side surface of the third lens 113 and the object-side surface of the fourth lens 114 can function as the aperture stop.

[0260] The object-side and sensor-side surfaces of the first through eighth lenses 111 through 118 may be aspherical. At least one of the first through eighth lenses 111 through 118 may be made of a glass molded material. For example, at least one of the third and fourth lenses 113 and 114 may be a glass molded lens; specifically, the fourth lens 114 may be made of a glass molded material. The first, second, third, and eighth lenses 111, 112, 113, 115, 116, 117, and 118 may be made of plastic. The placement of these glass molded lenses in lens unit 100A reduces TTL.

[0261] The optical system 1000 may further include: Figure 23The optical path changing member 400 is shown. The optical path changing member 400 can reflect light incident from the outside and change the light's path from the second path OA2 to the first path OA1. The optical path changing member 400 may include a reflector or a prism. For example, the optical path changing member 400 may include a right-angle prism. When the optical path changing member 400 includes a right-angle prism, the optical path changing member 400 can reflect the second path OA2 of the incident light at an angle of 90 degrees to change the first path OA1 of the light. The first path OA1 may be located along the optical axis of the optical system. The optical path changing member 400 may be arranged closer to the object side than the lens unit 100A. That is, when the optical system 1000 includes the optical path changing member 400, the optical path changing member 300, the first lens 111 to the eighth lens 118, the optical filter 500, and the image sensor 300 may be arranged in this order from the object side to the sensor side. The optical path changing member 400 will be described with reference to the first embodiment.

[0262] Reference Figures 12 to 14 , the first lens group G1 may include a first lens 111 , a second lens 112 , and a third lens 113 , the second lens group G2 may include a fourth lens 114 and a fifth lens 115 , and the third lens group G3 may include a sixth lens 116 , a seventh lens 117 , and an eighth lens 118 .

[0263] The first lens 111 can be arranged closest to the object side of the lens unit 100A, and the eighth lens 118 can be arranged closest to the image sensor 300 side. The first lens 111 can have a positive (+) refractive power along the optical axis OA. The first lens 111 can include a plastic material or a glass material, and can be, for example, a plastic material. The object-side first surface S1 of the first lens 111 can have a convex shape along the optical axis OA, and the sensor-side second surface S2 can have a concave shape along the optical axis OA. That is, the sixth lens 116 can have a meniscus shape that convexes from the optical axis OA toward the object side. Alternatively, the first lens 111 can have a convex second surface S2 along the optical axis OA. At least one or both of the first surface S1 and the second surface S2 can be aspherical. The center thickness CT1 of the first lens 111 is the thickness along the optical axis and can be thicker than the edge thickness ET1. The edge thickness ET1 is the optical axis distance between the edge of the object-side surface and the edge of the sensor-side surface of the first lens 111. Therefore, the first lens 111 may improve optical aberration or control incident light.The first surface S1 and the second surface S2 may be arranged to have no critical point from the optical axis to the end of the effective area.

[0264] The second lens 112 may have positive (+) or negative (-) refractive power on the optical axis OA, for example, it may have positive refractive power. The second lens 112 may include a plastic material or a glass material, for example, it may be a plastic material. The third surface S3 of the second lens 112 may have a convex shape on the optical axis OA, and the fourth surface S4 on the sensor side may have a concave shape on the optical axis OA. The second lens 112 may have a meniscus shape that is convex 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 112 may have a shape that is convex 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 112 may have a meniscus shape that is convex 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 112 may have a shape with both sides concave on the optical axis OA. At least one or both of the third surface S3 and the fourth surface S4 may be aspherical. The third surface S3 and the fourth surface S4 may be arranged so that there is no critical point from the optical axis to the end of the effective area.

[0265] The third lens 113 may have a refractive power opposite to that of the first lens 111 on the optical axis OA. That is, the third lens 113 may have a negative (-) refractive power. The third lens 113 may include a plastic material or a glass material, and may be, for example, a plastic material. The object-side fifth surface S5 of the third lens 113 may have a concave shape on the optical axis OA, and the sensor-side sixth surface S6 may have a concave shape on the optical axis OA. That is, the third lens 113 may have a shape with two concave sides on the optical axis OA. Alternatively, the fifth surface S5 may have a convex shape on the optical axis OA, and the sixth surface S6 may have a concave shape on the optical axis OA. That is, the third lens 113 may have a meniscus shape that convexes from the optical axis OA toward the object side. At least one or both of the fifth surface S5 and the sixth surface S6 may be aspherical. The fifth surface S5 and the sixth surface S6 may be arranged so that there is no critical point from the optical axis to the end of the effective area.

[0266] The object-side first lens 111 of the first lens group G1 can have a refractive power opposite to that of the sensor-side third lens 113. Therefore, the multiple lenses 111, 112, and 113 included in the first lens group G1 can mutually compensate for any chromatic aberration. The third lens 113, which is adjacent to the second lens group G2 in the first lens group G1, can have the highest refractive index within the first lens group G1. For example, the refractive index of the third lens 113 can be 1.6 or less. Therefore, since the first lens group G1 controls the dispersion of light provided to the second lens group G2, the lens size of the second lens group G2 can be reduced.

[0267] The fourth lens 114 may have a positive (+) refractive power on the optical axis OA. The fourth lens 114 may include a plastic material or a glass material, for example, a glass molded material, and may have a refractive index of 1.6 or less. The object-side seventh surface S7 of the fourth lens 114 may have a convex shape on the optical axis OA, and the sensor-side eighth surface S8 may have a convex shape on the optical axis OA. That is, the fourth lens 114 may have a shape that is convex on both sides on the optical axis OA. Conversely, the seventh surface S7 may be convex on the optical axis OA, and the eighth surface S8 may be concave on the optical axis OA. That is, the fourth lens 114 may have a meniscus shape that is convex toward the object on the optical axis OA. At least one or both of the seventh surface S7 and the eighth surface S8 may be aspherical. The seventh surface S7 and the eighth surface S8 may be arranged so that there is no critical point from the optical axis to the end of the effective area.

[0268] The fifth lens 115 may have positive (+) or negative (-) refractive power on the optical axis OA. The fifth lens 115 may have negative refractive power on the optical axis OA, which is opposite to the refractive power of the fourth lens 114. The fifth lens 115 may include a plastic material or a glass material, and may be, for example, a plastic material. The object-side ninth surface S9 of the fifth lens 115 may have a concave shape on the optical axis OA, and the sensor-side tenth surface S10 may have a convex shape on the optical axis OA. In other words, the fifth lens 115 may have a meniscus shape that convexes from the optical axis OA toward the sensor side. 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. The ninth surface S9 of the fifth lens 115 may be configured to be free of at least one critical point. As another example, the ninth surface S9 of the fifth lens 115 may have a convex 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 115 may have a shape that is convex on both sides on the optical axis OA. Differently, 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. Conversely, the ninth surface S9 may have a convex shape on the optical axis OA, and the tenth surface S10 may have a concave shape on the optical axis OA.

[0269] The fourth lens 114 has a convex shape on both sides, and the center thickness CT4 of the fourth lens 114 can be thicker than the edge thickness ET4, for example, more than twice. Therefore, the gap between the fourth lens 114 and the fifth lens 115 can be reduced. The difference in Abbe number between the fourth lens 114 and the fifth lens 115 can be greater than 20 or greater than 30, and can be less than 60. Therefore, the second lens group G2 can minimize changes in chromatic aberration caused by position changes according to changes in the operating mode.

[0270] The sixth lens 116 can have positive (+) or negative (-) refractive power on the optical axis OA, and can, for example, have negative refractive power. The sixth lens 116 can include a plastic material or a glass material, and can, for example, be made of a plastic material. The object-side eleventh surface S11 of the sixth lens 116 can have a concave shape on the optical axis OA, and the sensor-side twelfth surface S12 can have a concave shape on the optical axis OA. In other words, the sixth lens 116 can have a shape that is concave on both sides on the optical axis OA. Alternatively, the eleventh surface S11 can have a convex shape on the optical axis OA, and the twelfth surface S12 can have a convex shape on the optical axis OA. In other words, the sixth lens 116 can have a shape that is convex on both sides on the optical axis OA. Alternatively, the eleventh surface S11 can have a concave shape on the optical axis OA, and the twelfth surface S12 can have a convex shape 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 concave shape on the optical axis OA. At least one or both of the eleventh surface S11 and the twelfth surface S12 of the sixth lens 116 may be aspherical. The eleventh surface S11 and the twelfth surface S12 may be arranged so as to have no critical point from the optical axis to the end of the effective area.

[0271] The seventh lens 117 can have positive (+) or negative (-) refractive power on the optical axis OA, and can have positive refractive power. The seventh lens 117 has a refractive power on the optical axis OA that is opposite to that of the sixth lens 116 to improve chromatic aberration. The seventh lens 117 can include a plastic material or a glass material, and can be, for example, a plastic material. The object-side thirteenth surface S13 of the seventh lens 117 can have a convex shape on the optical axis OA, and the sensor-side fourteenth surface S14 can have a convex shape on the optical axis OA. In other words, the seventh lens 117 can have a convex shape on both sides on the optical axis OA. As another example, the thirteenth surface S13 can have a convex shape on the optical axis OA, and the fourteenth surface S14 can have a convex shape on the optical axis OA. In other words, the seventh lens 117 can have a shape that is convex on both sides on the optical axis OA. Alternatively, the thirteenth surface S13 can have a concave shape on the optical axis OA, and the fourteenth surface S14 can have a convex shape on the optical axis OA. That is, the seventh lens 117 can have a meniscus shape that is convex toward the sensor on the optical axis OA. Alternatively, the thirteenth surface S13 can have a concave shape on the optical axis OA, and the fourteenth surface S14 can have a concave shape on the optical axis OA. That is, the seventh lens 117 can have a shape with both sides concave on the optical axis OA. At least one or both of the thirteenth surface S13 and the fourteenth surface S14 can be aspherical. The thirteenth surface S13 and the fourteenth surface S14 of the seventh lens 117 can be arranged so that there is no critical point from the optical axis to the end of the effective area. The sixth lens 116 and the seventh lens 117 have opposite refractive powers, and the Abbe number difference is set to be less than 10 to control chromatic aberration. Therefore, the third lens group G3 can minimize the change in chromatic aberration caused by the position changing according to the mode change and can perform the achromatic effect.

[0272] The eighth lens 118 may have a negative (-) refractive power on the optical axis OA. The eighth lens 118 may include a plastic material or a glass material, and may be, for example, a plastic material. The object-side fifteenth surface S15 of the eighth lens 118 may have a convex shape on the optical axis OA, and the sensor-side sixteenth surface S16 may have a concave shape on the optical axis OA. That is, the eighth lens 118 may have a meniscus shape that is convex toward the sensor side on the optical axis OA. Alternatively, the eighth lens 118 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 118 may have a meniscus shape that is convex toward the sensor side on the optical axis OA. At least one or both of the fifteenth surface S15 and the sixteenth surface S16 may be aspherical.

[0273] At least one of the fifteenth surface S15 on the object side and the sixteenth surface S16 on the sensor side of the eighth lens 118 may have a critical point. For example, the fifteenth surface S15 may be configured to have no critical point, while the sixteenth surface S16 may have a critical point. A critical point is a point where the slope value changes from positive (+) to negative (-), or from negative (-) to positive (+), relative to the sign of the optical axis OA and the direction perpendicular to the optical axis OA, and may represent a point where the slope value is zero. Alternatively, a critical point may be a point where the slope value of a tangent line passing through the lens surface increases and then decreases, or decreases and then increases. The center thickness CT8 of the eighth lens 118 may be thinner than the edge thickness ET8. Therefore, due to the difference between the center and edge thicknesses of the eighth lens 118, uniform light distribution can be provided to the periphery of the image sensor 300.

[0274] Among the multiple lens groups G1, G2, and G3, the third lens group G3 may be closest to the image sensor 300. The third lens group G3 may be movable in the optical axis direction, and the optical axis distance (BFL) between the eighth lens 118 and the image sensor 300 may vary depending on the operating mode. The third lens group G3 may function to control the chief ray angle (CRA). Specifically, the CRA of the optical system 1000 according to an embodiment may be less than approximately 15 degrees, and the eighth lens 118 of the third lens group G3 may correct the chief ray angle (CRA) of light incident on the image sensor 300 according to various operating modes. A camera module according to a second embodiment of the present invention may include the above-described optical system 1000. The camera module may move the second lens group G2 and the third lens group G3 of the multiple lens groups G1, G2, and G3 included in the optical system 1000 in the optical axis OA direction. The camera module may include a drive member (not shown) connected to the optical system 1000. The drive member is arranged outside the second lens group G2 and outside the third lens group G3 and may be moved in the optical axis OA direction according to the operating mode.

[0275] The operating mode may include a first mode that moves at a first magnification and a third mode that operates at a second magnification different from the first magnification. In this case, the second magnification may be greater than the first magnification. In addition, the operating mode may include a second mode having a magnification between the first mode and the third mode. Here, the first magnification may be the lowest magnification of the optical system 1000, and the second magnification may be the highest magnification of the optical system 1000. Between the first magnification and the second magnification, the first magnification may be a magnification of about 2.5 to about 5, the second magnification may be a magnification of about 6 to about 11, and the third magnification may be a magnification of about 4 to about 6. The first mode may be a wide-angle mode, the second mode may be a mid-focus mode, and the third mode may be a telephoto mode.

[0276] The driving member can move the second lens group G2 and the third lens group G3, or operate them in an initial mode according to an operating mode selected from the first mode to the third mode. Specifically, each of the multiple driving members is connected to the second lens group G2 or the third lens group G3, and can move the second lens group G2 or the third lens group G3 according to the operating mode. The initial mode can be any one of the first mode, the second mode and the third mode, and for example, it can be the second mode or the mid-focus mode. For example, in the first mode, each of the second lens group G2 and the third lens group G3 can be located at a position defined as the first position (position 1). In the second mode, each of the second lens group G2 and the third lens group G3 can be located at a second position (position 2) defined as closer to the object than the first position. In the third mode, each of the second lens group G2 and the third lens group G3 can be located at a third position (position 3) defined as closer to the sensor side than the first position. The first position can be an area between the second position and the third position.

[0277] The first position of the second lens group G2 in the first mode may be a region between the second position and the third position of the second lens group G2 in the second and third modes. The first position of the third lens group G3 in the first mode may be a region between the second position and the third position of the third lens group G3 in the second and third modes.

[0278] The optical system 1000 according to the second embodiment can be configured such that the second lens group G2 and the third lens group G3 can be moved according to the operating mode, and the first lens group G1 can be located in a fixed position. Depending on the operating mode, the second lens group G2 or the third lens group G3 can be moved, and the first lens group G1 can be arranged in a fixed position. Depending on the operating mode, in each of the first position, the second position, and the third position, the first lens group G1, the second lens group G2, and the third lens group G3 can have a set spacing with adjacent lens groups. Therefore, the optical system 1000 can have a constant total lens length (TTL) and a variable BFL according to the operating mode, and the effective focal length and magnification of the optical system 1000 can be controlled by controlling the positions of some lens groups.

[0279] The effective diameter of the first lens 111 is the largest among the lenses, and the effective diameter of the sixth lens 116 is the smallest among the lenses. The Abbe number of the fourth lens 114 may be the largest among the lenses and may be greater than 60. In terms of absolute focal length, the focal length of the second lens 112 may be the largest among the lenses, and the difference in focal length (absolute value) between two adjacent lenses may be the largest between the second lens 112 and the third lens 113, and the smallest between the sixth lens 116 and the seventh lens 117.

[0280] Depending on the operating mode, the optical axis distance DG12 between the first lens group G1 and the second lens group G2, and the optical axis distance DG23 between the second lens group G2 and the third lens group G3 can be 0.2 mm or greater and 8 mm or less. Depending on the operating mode, the F-number of the optical system 1000 provides brightness of 2.0 or greater, and can be within a range of 2.2 to 3.8. An aperture stop can be located between the first lens group G1 and the second lens group G2.

[0281] The optical system 1000 according to the second embodiment can satisfy at least one or more of the mathematical formulas described below. Therefore, the optical system 1000 according to the embodiment can effectively correct aberrations that change depending on the operating mode. Furthermore, the optical system 1000 according to the embodiment can effectively provide autofocus (AF) functionality for an object at various magnifications and can have a slim and compact structure. Hereinafter, the center thicknesses of the first to eighth lenses 111 to 118 can be defined as CT1 to CT8, the edge thicknesses can be defined as ET1 to ET8, and the optical axis distances between adjacent lenses, from the distance between the first and second lenses to the distance between the seventh and eighth lenses, can be defined as CG1 to CG7. The average effective diameters of the object-side and sensor-side surfaces of the first to eighth lenses 111 to 118 can be defined as CA1 to CA8, and the effective diameters from the object-side and sensor-side surfaces of the first lens 111 to the object-side and sensor-side surfaces of the eighth lens 118 can be defined as CA11, CA12, CA81, and CA82. The units of the thickness, spacing, and effective diameter values ​​are in mm. In addition, the effective diameter refers to the case where the lens is in a circular or partially circular shape, and can be defined as the effective diameter or maximum diameter when the lens is in a partially circular shape.

[0282] [Formula 1] n_G1, n_G2, n_G3>1 (n_G1, n_G2, n_G3 are natural numbers)

[0283] In Formula 1, n_G1, n_G2, and n_G3 represent the number of lenses included in each of the first lens group G1, the second lens group G2, and the third lens group G3. Here, they may have a relationship of n_G1>n_G2, n_G3>n_G2.

[0284] [Equation 2] 0.7<CA41 / CA11<1.2

[0285] In Formula 2, CA41 is the maximum effective diameter of the seventh surface S7 of the fourth lens 114, and CA11 is the maximum effective diameter of the first surface S1 of the first lens 111. If Formula 2 is satisfied, a higher EPD (entrance pupil diameter) than the optical system can be provided.

[0286] [Formula 3] 2<CT1 / CT3<5

[0287] In Formula 3, CT1 is the thickness (mm) of the first lens 111 along the optical axis, and CT3 is the thickness of the third lens 113 along the optical axis. If Formula 3 is satisfied, aberration characteristics in the optical system 1000 can be improved. Preferably, 2.5<CT1 / CT3<4 can be satisfied.

[0288] [Formula 4] 0<CT1 / CT4<1

[0289] In Formula 4, CT3 represents the thickness (mm) of the fourth lens 114 along the optical axis OA. When the optical system 1000 according to the embodiment satisfies Formula 4, the optical system 1000 can improve aberration characteristics. Preferably, 0.5<CT1 / CT4<0.85 can be satisfied.

[0290] [Formula 5]1.2<ET3 / CT3<3.2

[0291] In Formula 4, ET3 represents a thickness (mm) in the optical axis OA direction at an edge, which is an end of an effective area of ​​the third lens 113. When the optical system 1000 according to an embodiment satisfies Formula 5, the optical system 1000 may improve distortion characteristics.

[0292] [Formula 6] G1F<0

[0293] In Formula 6, G1F is the effective focal length (EFL) of the first lens group G1 and may have a value less than 0. It is the composite focal length of the first to third lenses. When Formula 6 is satisfied, optical aberrations of the optical system or the first lens group G1 may be improved.

[0294] [Formula 7] CRA<20 degrees

[0295] In Equation 7, CRA (chief ray angle) is the chief ray incident angle, and the incident angle of the chief ray in the optical system may be 20 degrees or less, and for example, may be 15 degrees or less. The first mode may be a wide-angle mode, the second mode may be a mid-focus mode, and the third mode may be a telephoto mode. Here, in the case of the first mode (wide angle), the chief ray incident angle may be greater than the chief ray incident angle in the case of the second mode at a field of 1.0. In the case of the third mode (telephoto), the chief ray incident angle may be 11 degrees or less at a field of 1.0, and the chief ray incident angle of the second mode may be less than the chief ray incident angle of the first mode. When Equation 6 is satisfied, the peripheral illumination ratio can be ensured.

[0296] [Equation 8] (TTL / DG1)>3.5

[0297] In Equation 8, DG1 is the optical axis distance of the first lens group G1, and is, for example, the optical axis distance from the center of the object-side surface of the first lens 111 to the center of the sensor-side surface of the third lens 113. For example, DG1 represents the distance (mm) between the first surface S1 of the first lens 111 and the sixth surface S6 of the third lens 113 on the optical axis OA. TTL (Total Track Length) represents the distance (mm) from the object-side first surface S1 of the first lens 111 to the imaging surface of the image sensor 300 on the optical axis OA. When the optical system 1000 according to an embodiment satisfies Equation 8, the optical system 1000 has a relatively small TTL and can ensure a high peripheral illumination ratio.

[0298] [Formula 9]2<TTL / EPD3<7

[0299] In Equation 9, EPD3 represents the size of the EPD of the optical system 1000 when operating in the third mode (i.e., telephoto mode). When the optical system 1000 according to an embodiment satisfies Equation 9, the optical system 1000 can ensure a bright image when operating in the third mode, and can be the minimum condition for ensuring an F-number of 4 or less in telephoto mode. Preferably, 3<TTL / EPD3<5 can be satisfied.

[0300] [Formula 9-1] 3<TTL / EPD1<7

[0301] [Formula 9-2] 2<TTL / EPD2<6

[0302] [Equation 9-3] (TTL / EPD3)<(TTL / EPD2)<(TTL / EPD1)

[0303] In equations 9-1 to 9-3, EPD1 is the size of the EPD of the optical system in the first mode (wide angle), and EPD2 is the size of the EPD of the optical system in the second mode (mid focus). When the optical system meets the above conditions, it can ensure a bright image according to each mode.

[0304] [Equation 10] 2<CT_Max / CT_Min<6

[0305] In Formula 10, CT_Max is the thickest thickness among the center thicknesses of the lens, and CT_Min is the thinnest thickness among the center thicknesses of the lens, and the aberration characteristics of the optical system can be improved when Formula 10 is satisfied. Preferably, 3<CT_Max / CT_Min<5.5 can be satisfied.

[0306] [Equation 11] 1<CA_Max / CA_Min<3

[0307] In Equation 11, CA_Max is the maximum effective diameter in the lens, and CA_Min is the minimum effective diameter in the lens, and when Equation 11 is satisfied, the optical performance of the optical system can be maintained, and a camera module with a thin or compact structure can be provided.

[0308] [Formula 12] 0.1<∑CG_Wide / TTL<0.6

[0309] In Equation 12, ∑CG_Wide is the sum of the center distances between adjacent lenses in the first mode. When the optical system satisfies Equation 12, the center distance DG12 between the first and second lens groups, as well as the center distance between the second and third lens groups, can be set according to the wide-angle mode. The center distance DG12 between the first and second lens groups can be the center distance CG3 between the third lens 113 and the fourth lens 114, and varies depending on the operating mode. The center distance DG23 between the second and third lens groups is the center distance CG5 between the fifth lens 115 and the sixth lens 116, and varies depending on the operating mode.

[0310] [Equation 12-1] 0.05<∑CG_Mid / TTL<0.4

[0311] [Formula 12-2]0<∑CG_Tele / TTL<0.3

[0312] In Equations 12-1 and 12-2, ∑CG_Mid is the sum of the center distances between adjacent lenses in the second mode, and ∑CG_Tale is the sum of the center distances between adjacent lenses in the third mode. When the optical system satisfies Equations 12-1 and 12-2, the center distance DG12 between the first lens group and the second lens group, as well as the center distance between the second lens group and the third lens group, can be set according to the mid-focus mode and the telephoto mode. When the optical system 1000 satisfies at least one or two or more of Equations 1 to 12, the optical system 1000 can have a thin and lightweight structure. In addition, the optical system 1000 can have an improved assemblability and mechanical stability.

[0313] [Equation 13] 0.5<DG1 / DG2<3

[0314] In Equation 13, DG1 is the optical axis distance of the first lens group G1 and, for example, represents the optical axis distance between the first surface S1 of the first lens 111 and the sixth surface S6 of the third lens 113. DG2 is the optical axis distance of the second lens group G2 and, for example, represents the optical axis distance between the seventh surface S7 of the fourth lens 114 and the tenth surface S10 of the fifth lens 115. In Equation 13, by setting the optical axis distance between the first lens group G1 and the second lens group G2, the TTL can be adjusted. Preferably, 0.8 < DG1 / DG2 < 1.5 can be satisfied.

[0315] [Equation 14] 0.5<DG2 / DG3<2

[0316] In Equation 14, DG2 represents the optical axis distance of the second lens group G2, for example, the optical axis distance between the seventh surface S7 of the fourth lens 114 and the tenth surface S10 of the fifth lens 115. DG3 represents the optical axis distance of the third lens group G3, for example, the optical axis distance between the eleventh surface S11 of the sixth lens 116 and the sixteenth surface S16 of the eighth lens 118. Preferably, 0.5<DG2 / DG3<1 can be satisfied. When the optical system 1000 according to an embodiment satisfies at least one of Equations 13 and 14, it has a relatively small TTL and can provide various magnifications according to at least three mode changes.

[0317] [Equation 15] 0<CG2 / TTL<0.2

[0318] In Equation 15, CG2 is the optical axis distance between the second lens 112 and the third lens 113. When the optical system 1000 satisfies Equation 15, the optical system 1000 has a relatively small TTL and can have improved optical characteristics by controlling stray light incident on the first lens group G1. Preferably, 0 < CG2 / TTL < 0.1 can be satisfied.

[0319] [Equation 16] 3<TTL / DG2<10

[0320] In Formula 16, DG2 is the optical axis distance of the second lens group G2. When the optical system 1000 according to the embodiment satisfies Formula 16, the optical system 1000 has a relatively small TTL and can improve chromatic aberration characteristics.

[0321] [Equation 17] 20<|Vd4-Vd5|<70

[0322] In Formula 17, Vd4 represents the Abbe number of the fourth lens 114, and Vd5 represents the Abbe number of the fifth lens 115. If the absolute value of the Abbe number difference between the fourth lens and the fifth lens of the optical system 1000 according to the embodiment satisfies Formula 17, the optical system 1000 can improve chromatic aberration characteristics.

[0323] [Equation 18] 15<|Vd8-Vd7|<60

[0324] In Formula 18, Vd8 represents the Abbe number of the eighth lens, and Vd7 represents the Abbe number of the seventh lens. If the absolute value of the Abbe number difference between the seventh lens and the eighth lens satisfies Formula 18, the optical system 1000 can improve chromatic aberration characteristics.

[0325] [Equation 19] 1.6<n1

[0326] In Equation 19, n1 represents the d-line refractive index of first lens 111. When optical system 1000 according to an embodiment satisfies Equation 19, incident light can be dispersed and the effective area of ​​the lenses arranged after first lens 111 can be ensured. The refractive indices of fourth lens 114 and eighth lens 118 can be less than 1.6, and the refractive index of fourth lens 114 can be the smallest among the lenses. The number of lenses having a refractive index of 1.63 or greater is two or more.

[0327] [Equation 20] 1<L1R1 / L3R2<2.5

[0328] In Equation 20, L1R1 represents the curvature radius of the object-side first surface S1 of the first lens 111, and L3R2 represents the curvature radius of the sensor-side sixth surface S6 of the third lens 113. When the optical system 1000 according to an embodiment satisfies Equation 20, the optical system 1000 can control stray light incident on the first lens group G1.

[0329] [Equation 21] 1.5<L1R1 / L4R1<3.5

[0330] In Formula 21, L1R1 represents the curvature radius of the object-side first surface S1 of the first lens 111, and L4R1 represents the curvature radius of the object-side seventh surface S7 of the fourth lens 114. When the optical system 1000 according to an embodiment satisfies Formula 21, the optical system 1000 can have good optical performance at various magnifications.

[0331] [Equation 22] 0<L3R2 / L4R1<2

[0332] In Equation 22, L3R2 represents the curvature radius of the sensor-side sixth surface S6 of the third lens 113, and L4R1 represents the curvature radius of the object-side seventh surface S7 of the fourth lens 114. When the optical system 1000 according to the embodiment satisfies Equation 22, the optical system 1000 can have good optical performance in the peripheral portion of the FOV when operating at various magnifications in at least three modes.

[0333] [Equation 23] 1<L1R1 / L8R2<3

[0334] In Equation 23, L1R1 represents the curvature radius of the object-side first surface S1 of the first lens 111, and L8R2 represents the curvature radius of the sensor-side sixteenth surface S16 of the eighth lens 118. When the optical system 1000 according to an embodiment satisfies Equation 23, the optical system 1000 can have good optical performance in the central portion and the peripheral portion of the FOV.

[0335] [Equation 24] 0<Mode12_mG2 / TTL<0.5

[0336] In Formula 24, Mode12_mG2 represents the difference in center distance after movement of the second lens group G2 when changing from the second mode to the first mode or from the first mode to the second mode (unit: mm). Specifically, Mode12_mG2 represents the movement distance of the second lens group G2 in the first mode and the second mode, and represents the difference between the optical axis distance between the first lens group G1 and the second lens group G2 in the first mode and the optical axis distance between the first lens group G1 and the second lens group G2 in the second mode. When the optical system 1000 according to the embodiment satisfies Formula 24, the optical system 1000 can minimize the movement distance of the second lens group G2 when the magnification changes, so that the optical system 1000 can have a light and thin structure. In addition, since the movement distance can be minimized when controlling the position of the second lens group G2, improved power consumption characteristics can be achieved.

[0337] [Equation 25] 0<Mode23_mG2 / TTL<0.5

[0338] In Formula 25, Mode23_mG2 represents the difference in center distance after movement of the second lens group G2 when operating from the second mode to the third mode or from the third mode to the second mode (unit: mm). Specifically, Mode23_mG2 represents the difference between the optical axis distance between the first lens group G1 and the second lens group G2 in the second mode and the optical axis distance between the first lens group G1 and the second lens group G2 in the third mode. The maximum movement distance of the second lens group G2 can be greater than the maximum movement distance of the third lens group G3. When the optical system 1000 according to the embodiment satisfies Formula 25, the optical system 1000 can minimize the movement distance of the second lens group G2 when the magnification changes, so that the optical system 1000 can have a light and thin structure. In addition, since the movement distance can be minimized when the position of the second lens group G2 is controlled, it can have improved power consumption characteristics.

[0339] [Equation 26] 0.3<Mode12_mG2 / DG2<1

[0340] Equation 26 represents the difference in center distance after movement of the second lens group G2 when Mode12_mG2 operates from the first mode to the second mode or from the second mode to the first mode. When the optical system 1000 according to the embodiment satisfies Equation 26, the optical system 1000 can minimize the movement distance of the second lens group G2 when the magnification changes, so that the optical system 1000 can have a light and thin structure. In addition, when the position of the second lens group G2 is controlled, the movement distance can be minimized, so that the optical system 1000 can have improved power consumption characteristics. DG2 is the optical axis distance of the second lens group G2. When the optical system 1000 according to the embodiment satisfies Equation 26, the optical system 1000 can minimize the movement distance of the second lens group G2 when the magnification changes, so that the optical system 1000 can have a light and thin structure. In addition, when the position of the second lens group G2 is controlled, the movement distance can be minimized, so that the optical system 1000 can have improved power consumption characteristics.

[0341] [Equation 27] 0<Mode23_mG3 / DG3<0.5

[0342] In Equation 27, Mode23_mG3 represents the difference in center distance after movement of the third lens group G3 when changing from the second mode to the third mode or vice versa. DG3 is the optical axis distance of the third lens group G3. When the optical system 1000 according to an embodiment satisfies Equation 27, the movement distance of the third lens group G3 can be minimized when the magnification is changed, allowing the optical system 1000 to have a thin and lightweight structure. In addition, since the movement distance can be minimized when controlling the position of the third lens group G3, it can have improved power consumption characteristics.

[0343] [Formula 28]1<(CT1 / ET1) / (CT3 / ET3)<5

[0344] In Formula 28, CT1 / ET1 is the value obtained by dividing the thickness of the first lens 111 along the optical axis by the thickness at the end, and CT3 / ET3 is the value obtained by dividing the thickness of the third lens 113 along the optical axis by the thickness at the end. If the values ​​obtained by dividing the center thickness of the first lens 111 and the third lens 113 by the end thickness satisfy Formula 28 under the above ratio, chromatic aberration can be improved and incident light can be controlled.

[0345] [Equation 29] 0.5<(CT1 / ET1) / (CT7 / ET7)<1.5

[0346] In Formula 29, CT1 / ET1 is a value obtained by dividing the thickness of the seventh lens 117 along the optical axis by the thickness of the end portion. If the value obtained by dividing the center thickness of the first lens 111 and the seventh lens 117 by the end thickness satisfies Formula 29 having the above ratio, chromatic aberration can be improved and incident light can be controlled.

[0347] [Equation 30] 1<Mode1(DG12 / DG23)<5

[0348] In Equation 30, Mode1(DG12 / DG23) represents the ratio of the center distance DG12 between the first lens group and the second lens group to the center distance DG23 between the second lens group and the third lens group in the first mode. If the optical system 1000 according to an embodiment satisfies Equation 30, the optical system 1000 can have improved optical characteristics at the first magnification. Specifically, the optical system 1000 can have improved aberration characteristics at the first magnification, and can improve optical performance in the central and peripheral portions of the FOV.

[0349] [Equation 31] 0<Mode3(DG12 / DG23)<0.7

[0350] In Equation 31, Mode3(DG12 / DG23) represents the ratio of the center distance DG12 between the first lens group and the second lens group to the center distance DG23 between the second lens group and the third lens group in the third mode. When the optical system 1000 according to an embodiment satisfies Equation 31, the optical system 1000 can have improved optical characteristics at the second magnification. Specifically, the optical system 1000 can have improved aberration characteristics at the second magnification, and can improve optical performance in the peripheral portion of the FOV.

[0351] [Equation 32] 0.5<TD2 / TTL<1

[0352] In Equation 32, TD2 is the optical axis distance from the center of the object-side surface of the first lens element to the center of the sensor-side surface of the eighth lens element in the second mode. When the optical system 1000 according to an embodiment satisfies Equation 32, the optical system 1000 can have improved optical characteristics in the mid-focus mode. Specifically, the optical system 1000 can have improved aberration characteristics in the mid-focus mode and can improve optical performance in the peripheral portion of the field of view (FOV).

[0353] [Equation 33] 1<TD1 / TD2<1.5

[0354] In Equation 33, TD1 is the optical axis distance from the center of the object-side surface of the first lens to the center of the sensor-side surface of the eighth lens in the first mode. When the optical system 1000 according to an embodiment satisfies Equation 33, the optical system 1000 can have improved optical characteristics in both the first and second modes. Specifically, the optical system 1000 can have improved aberration characteristics in both the first and second modes, and can improve optical performance in the peripheral portion of the FOV.

[0355] [Equation 34] 10 mm < TD3 < TD2 < TD1 < 20 mm

[0356] Equation 34 compares the optical axis distances of the lenses in the first, second, and third modes, and TD3 is the optical axis distance from the center of the object-side surface of the first lens to the center of the sensor-side surface of the eighth lens in the third mode. When the optical system 1000 according to an embodiment satisfies Equation 34, the optical system 1000 can exhibit improved optical characteristics in the first, second, and third modes. Specifically, the optical system 1000 can exhibit improved aberration characteristics in the first, second, and third modes, and improve optical performance in the peripheral portion of the field of view (FOV).

[0357] [Equation 35] 0.5<BFL2 / TTL<1

[0358] In Equation 35, BFL2 (Back Focus 2) is the optical axis distance from the center of the sensor-side surface of the eighth lens element to the imaging surface of the image sensor in the second mode. When the optical system 1000 according to an embodiment satisfies Equation 35, the optical system 1000 can adjust the focus position toward the imaging surface of the image sensor 300 in the second mode. Specifically, the optical system 1000 has improved optical characteristics in the second mode, and can improve optical performance in the peripheral portion of the FOV.

[0359] [Equation 36] 2<BFL3 / BFL1<4

[0360] In Equation 36, BFL3 is the optical axis distance from the center of the sensor-side surface of the eighth lens to the imaging surface of the image sensor in the third mode. When the optical system 1000 according to an embodiment satisfies Equation 36, the optical system 1000 can adjust the focus position toward the imaging surface of the image sensor 300 in the first and third modes. Specifically, the optical system 1000 has improved optical characteristics in the first and third modes, and can improve optical performance in the peripheral portion of the FOV.

[0361] [Equation 37] 1.5<TD3 / BFL3<3

[0362] Equation 37 compares the optical axis distance (TD3) between the center of the object-side surface of the first lens and the center of the sensor-side surface of the eighth lens in the third mode, and the optical axis distance (BFL3) from the center of the sensor-side surface of the eighth lens 118 to the imaging surface of the image sensor. When the optical system 1000 according to an embodiment satisfies Equation 37, the optical system 1000 can have improved optical characteristics in the third mode. Specifically, the optical system 1000 can have improved aberration characteristics in the third mode and can improve optical performance in the peripheral portion of the FOV.

[0363] [Formula 38] 2<Mode_CG_Max / Mode_CG_Min<8

[0364] In Equation 38, Mode_CG_Max represents the maximum center distance among the center distances between the first lens and the eighth lens in the first, second, and third modes, and Mode_CG_Min represents the minimum center distance among the center distances between the first lens and the eighth lens in the first, second, and third modes. When the optical system satisfies Equation 38, the TTL and optical axis distance of the lenses according to each mode can be adjusted.

[0365] [Formula 39]1<BFL1<10

[0366] Equation 39 represents the optical axis distance between the eighth lens and the image sensor in the first mode. When the optical system satisfies Equation 39, the focus position on the imaging surface of the image sensor in the first mode can be adjusted.

[0367] [Equation 40] 30<Aver_Abbe<50

[0368] In Formula 40, Aver_Abbe is an average value of the Abbe numbers of the first to eighth lenses. When the optical system satisfies Formula 40, the optical system 1000 may have improved aberration characteristics and resolution.

[0369] [Equation 41] 1.5<Aver_Index<1.8

[0370] In Equation 40, Aver_Index is an average value of the refractive indices of the first to eighth lenses. When the optical system satisfies Equation 41, the optical system 1000 may have improved aberration characteristics and resolution.

[0371] [Equation 41-1] 10<∑Abbe / ∑Index<40

[0372] In Formula 41-1, ∑Abbe represents the sum of the Abbe numbers of each of the multiple lenses. ∑Index represents the sum of the refractive indices of each of the multiple lenses. When the optical system 1000 according to the embodiment satisfies Formula 41-1, the optical system 1000 can have improved aberration characteristics and resolution. Preferably, the following Formula 41-1 can satisfy: 15<∑Abb / ∑Index<25. Preferably, the following condition can be satisfied: (∑Abb-∑Index)<280.

[0373] [Equation 42] 2<|G1F / G2F|<4

[0374] In Equation 42, G1F represents the EFL of the first lens group G1, and G2F represents the EFL of the second lens group G2. G2F is the combined focal length of the fourth and fifth lenses. If Equation 42 is satisfied, the size of the optical system can be reduced, for example, in a TTL configuration. Preferably, G2F > 0. G3F is the combined focal length of the sixth through eighth lenses, and G3F < 0. Furthermore, the following condition can be satisfied: |G1F| > |G3F| > G2F.

[0375] [Equation 43] 1<M2F / M1F<10

[0376] In equation 43, M1F is the effective focal length of the optical system in the first mode, and M2F is the effective focal length of the optical system in the second mode. Preferably, 1<M2F / M1F<3 can be satisfied. When the optical system satisfies equation 43, the effective focal length can be adjusted according to the first mode and the second mode.

[0377] [Formula 43-1] 1<M3F / M2F<10

[0378] In Equation 43, M3F is the effective focal length of the optical system in the third mode. Preferably, 1 < M3F / M2F < 3 can be satisfied, and the following condition can be satisfied: (M3F / M1F) > (M3F / M2F). When the optical system satisfies Equation 43-1, the effective focal length can be adjusted according to the second mode and the third mode.

[0379] [Equation 44] 2<M2F / EPD2<7

[0380] In Formula 44, M2F is the effective focal length of the optical system in the second mode (mid-focus), and EPD2 represents the size of the EPD of the optical system 1000 in the second mode. When the optical system 1000 according to the embodiment satisfies Formula 44, the optical system 1000 can ensure a bright image when operating in the second mode.

[0381] [Equation 45] 0.1<M1F / EPD1<3

[0382] In Equation 34, M1F is the effective focal length of the optical system in the first mode (wide angle), and EPD1 represents the size of the EPD when the optical system 1000 operates in the first mode. When the optical system 1000 according to the embodiment satisfies Equation 45, the optical system 1000 can ensure a bright image when operating in the first mode.

[0383] [Equation 46] M1F<M2F<M3F

[0384] In Equation 46, M1F, M2F, and M3F represent effective focal lengths of the optical system in the first mode, the second mode, and the third mode. The effective focal length in the third mode may be the largest, and the effective focal length in the first mode may be the smallest.

[0385] [Equation 47] 0<TTL / M2F<2

[0386] Equation 47 can adjust TTL by comparing the effective focal length in TTL and the second mode. Preferably, 1<TTL / M2F<2 can be satisfied.

[0387] [Equation 48] 0.1<TTL / M1F<5

[0388] The TTL can be adjusted by comparing the TTL with the effective focal length in the first mode according to Equation 47. Preferably, 1<TTL / M1F<4 can be satisfied.

[0389] [Equation 49] 1<CA_Max / ImgH<3

[0390] In Equation 49, CA_Max represents the size of the maximum effective diameter (CA) in the lens surface of the lens unit 100A included in the optical system 1000. ImgH is the distance from the 0 field area at the center of the imaging surface of the image sensor 300 overlapping with the optical axis OA to the 1.0 field area of ​​the image sensor 300. ImgH represents 1 / 2 of the maximum diagonal length of the effective area of ​​the image sensor 300. If the optical system 1000 according to the embodiment satisfies Equation 49, the optical system 1000 can be provided in a light, thin and compact manner. In addition, the optical system 1000 can achieve high resolution and high image quality. The range of ImgH is 2 mm to 3 mm.

[0391] [Equation 50] 5<TTL / ImgH<12

[0392] If the optical system 1000 satisfies Equation 39, the optical system 1000 can have a smaller TTL, so that the optical system 1000 can be provided in a light, thin and compact manner. Preferably, the range can be 6<TTL / ImgH<10.

[0393] [Formula 51] 1<BFL2 / ImgH<3

[0394] If the optical system 1000 according to an embodiment satisfies Equation 51, the BFL required for a small image sensor smaller than 1 inch can be ensured. Furthermore, if the optical system 1000 satisfies Equation 51, the optical system 1000 can operate at various magnifications while maintaining TTL, and can exhibit excellent optical characteristics in both the central and peripheral portions of the FOV. Preferably, it can be within the range of 2 < BFL2 / ImgH < 3.

[0395] [Formula 52] 2<BFL3 / ImgH<4;

[0396] If the optical system 1000 according to an embodiment satisfies Equation 52, the BFL required for small image sensors smaller than 1 inch can be ensured. Furthermore, when the optical system 1000 satisfies Equation 51, the optical system 1000 can operate at various magnifications while maintaining TTL and can exhibit excellent optical characteristics in both the central and peripheral portions of the FOV. Preferably, 2.5 < BFL3 / ImgH < 3.5 can be satisfied.

[0397] [Equation 53] 1<EPD1<EPD2<EPD3<7

[0398] In Equation 53, EPD1, EPD2, and EPD3 represent the sizes of EPDs of the optical system according to the first to third modes, and the brightness can be adjusted according to the respective modes.

[0399] [Formula 54]0<Max_Distortion<3

[0400] In Equation 54, Distortion represents the maximum value or maximum value of distortion from the center (0.0F) to the diagonal end (1.0F) of the image sensor based on the optical characteristics detected by image sensor 300. When optical system 1000 satisfies Equation 54, optical system 1000 can improve distortion characteristics and set conditions for image processing. Preferably, Distortion < 1.5 can be satisfied.

[0401] [Equation 55] 8<FOV3<FOV2<FOV1<45

[0402] In Equation 55, FOV1, FOV2, and FOV3 represent the diagonal fields of view of the optical system in the first, second, and third modes. FOV represents the field of view (degrees) in the diagonal direction of the optical system 1000, and an optical system with an angle of less than 45 degrees may be provided.

[0403] The aspheric coefficients of the lenses of the optical system of the second embodiment refer to Equation 56 of the first embodiment.

[0404] The optical system 1000 according to the second embodiment can satisfy at least one of the above-mentioned equations 1 to 55. Therefore, the optical system 1000 and the camera module can have improved optical characteristics. Specifically, since the optical system 1000 satisfies at least one or two or more of the above-mentioned equations 1 to 55, it is possible to effectively correct the degradation of optical characteristics caused by the movement of the lens group, such as chromatic aberration, vignetting, diffraction effects, and degradation of peripheral image quality. In addition, the optical system 1000 according to the embodiment can significantly reduce the movement distance of the lens group and provide an autofocus (AF) function for each magnification with excellent power consumption characteristics.

[0405] Since the optical system 1000 satisfies at least one or two of Equations 1 to 55, it may have improved assembly characteristics and a mechanically stable shape, and be provided with a thin and light structure, so that the optical system 1000 and a camera module including the same may have a compact structure.

[0406] Hereinafter, the optical system 1000 according to the second embodiment and the change from the first mode to the third mode will be described in more detail. In the optical system 1000, the first lens group G1 can be fixed, and the second lens group G2 and the third lens group G3 can be moved according to the operation mode. The first lens group G1 can include three lenses, for example, a first lens 111, a second lens 112, and a third lens 113, and the second lens group G2 can include two lenses, for example, a fourth lens 114 and a fifth lens 115. In addition, the third lens group G3 can include three lenses, for example, a sixth lens 116, a seventh lens 117, and an eighth lens 118. In the optical system 1000 according to the embodiment, the object-side surface (seventh surface S7) of the fourth lens 114 can be used as an aperture stop, and the above-mentioned optical filter 500 can be arranged between the fourth lens group G4 and the image sensor 300.

[0407] Figure 15 The curvature radius of the optical axis OA of the first lens 111 to the eighth lens 118, the center thickness CT of the lens, the center distance CG between adjacent components (eg, lenses), the refractive index at the d-line, the Abbe number, and the effective diameter (CA) are shown. Figure 15 , the object-side surfaces and sensor-side surfaces of the first to eighth lenses (lenses 1 to 8) are depicted as S1 and S2, DG12 is the optical axis distance between the third lens 103 and the fourth lens 104, and DG23 is the optical axis distance between the fifth lens 105 and the sixth lens 106. DG4 is the optical axis distance between the seventh lens and the optical filter 500, and may vary according to the movement of the third lens group G3.

[0408] [Table 6]

[0409]

[0410]

[0411] Referring to Table 6, the ratio CT / ET of the center thickness CT to the edge thickness ET of each lens of the lens unit 100A may be different from each other, and the CT / ET value of the fourth lens 114 may be the largest, and the CT / ET value of the eighth lens may be the smallest. The number of lenses having a CT / ET value less than 1 may be 5 or less, and may include the second lens, the third lens, the fifth lens, the sixth lens, and the eighth lens, and the value of CT / ET value greater than 2 may be 1, and may include the fourth lens. Figure 12 and Figure 13 As shown, the Abbe number Vd4 of the fourth lens 114 included in the second lens group G2 may be higher than the Abbe number Vd5 of the fifth lens 115 by 30 or more or 40 or more. Since the fourth lens 114 and the fifth lens 115 have the above-mentioned difference in Abbe number, the change in chromatic aberration that occurs when the magnification changes according to the movement M1 of the second lens group G2 can be minimized. Figure 12 and Figure 14 As shown, the Abbe number Vd8 of the eighth lens 118 included in the third lens group G3 may be higher than the Abbe number Vd7 of the seventh lens 117 by 20 or more or 30 or more. Since the seventh lens 117 and the eighth lens 118 have the above-mentioned difference in Abbe number, a change in chromatic aberration occurring when magnification changes according to the movement M2 of the third lens group G3 may be minimized and / or compensated, thereby performing an achromatic function.

[0412] The camera module according to the second embodiment can obtain information about an object at various magnifications. Specifically, the driving member can control the position of the second lens group G2 and the position of the third lens group G3, so that the camera module can operate at various magnifications. For example, referring to Figure 12 、 Figure 17 and Figure 20 , a camera module including the optical system 1000 can operate in a first mode having a first magnification. The first magnification can be approximately 3 times to approximately 5 times. Specifically, in an embodiment, the first magnification can be approximately 3.5 times. In the first mode, each of the second lens group G2 and the third lens group G3 can be moved to a set position. Therefore, each of the first lens group G3 to the third lens group G3 can be arranged at a set interval. For example, the second lens group G2 can be located in an area separated from the first lens group G1 by a first interval DG12, and the third lens group G3 can be located in an area separated from the second lens group G2 by a second interval DG23. Here, the first interval DG12 and the second interval DG23 can represent the interval between the lens groups on the optical axis OA and can vary according to the operating mode.

[0413] When the camera module operates in the first mode, the optical system 1000 may have a TTL value and a BFL1 value at a first position. Furthermore, the optical system 1000 may have an M1F defined as a first effective focal length (EFL) at the first position. Furthermore, the camera module may have a FOV of less than approximately 35 degrees and an F-number of less than approximately 3 in the first mode.

[0414] When the camera module operates in the second mode, the optical system 1000 may have a TTL value and a BFL2 value at the second position. Furthermore, the optical system 1000 may have an M2F defined as a second EFL at the second position. Furthermore, the camera module's FOV in the second mode may be less than approximately 25 degrees, and its F-number may be less than approximately 3.4. When the camera module operates in the third mode, the optical system 1000 may have a TTL value and a BFL3 value at the third position. Furthermore, the optical system 1000 may have an M3F defined as a third EFL at the third position. Furthermore, the camera module's FOV in the third mode may be less than approximately 20 degrees, and its F-number may be less than approximately 4.

[0415] like Figure 16 As shown in FIG. 1 , the relative illumination (RI) in each mode can be changed according to the height of the image sensor, and it can be seen that the relative illumination at the periphery or edge of the image sensor is above 50%. The optical system 1000 can have the following configuration in the first mode: Figure 17 and Figure 20 Specifically, Figure 17 is a graph of the diffraction MTF characteristics of the optical system 1000 operating in the first mode (first magnification), and Figure 20 This is a graph showing aberration characteristics. The diffraction MTF characteristic curve is measured in units of approximately 0.252 mm over a spatial frequency range of 0.000 mm to 2.2520 mm. In the diffraction MTF curve, T represents the MTF variation per millimeter of spatial frequency in the tangential direction, and R represents the MTF variation per millimeter of spatial frequency in the radial direction. Here, the MTF (Modulation Transfer Function) depends on the spatial frequency per millimeter period.

[0416] exist Figure 20 In the aberration graph, spherical aberration (longitudinal spherical aberration), astigmatism field curve and distortion are measured from left to right. Figure 17 In FIG, the X-axis may represent focal length (mm) and distortion (%), and the Y-axis may represent the height of the image. In addition, the graph of spherical aberration is a graph of light in the wavelength bands of about 435 nm, about 486 nm, about 546 nm, about 587 nm, and about 656 nm, and the graph of astigmatism and distortion is a graph of light in the wavelength band of 546 nm. Figure 20In the aberration diagram, the closer the curves are to the Y-axis, the better the aberration correction function can be explained. Figure 20 , it can be seen that the optical system 1000 according to the embodiment has measurement values ​​close to the Y-axis in almost all areas.

[0417] Table 7 and Figure 14 These are the items in the above-mentioned formula related to the optical system 1000 of the embodiment, including TTL (mm), back focal length (BFL), effective focal length F (mm), ImgH (mm), effective diameter CA (mm), thickness (mm), TD (mm) (optical axis distance from the first surface S1 to the fourteenth surface S14), the focal length F1, F2, F3, F4, F5, F6, F7 and F8 (mm) of each of the first to seventh lenses, the sum of the refractive indices of each lens, the sum of the Abbe numbers of each lens, the sum of the center thicknesses of each lens (mm), the sum of the center distances between adjacent lenses, the effective diameter, the diagonal FOV (degrees), the edge thickness ET, the focal lengths of the first lens group and the second lens group, the F number, etc.

[0418] [Table 7]

[0419] project value project value F1 21.61 ET1 1.148 F2 -99.05 ET2 1.404 F3 -8.175 ET3 1.017 F4 5.1405 ET4 0.916 F5 -47.86 ET5 1.950 F6 -7.395 ET6 1.607 F7 7.3326 ET7 1.461 F8 -9.701 ET8 1.046 G1F -15.89 ∑Index 12.923 G2F 5.78 ∑Abbe 280.298 G3F -10.81 ∑CT 10.654

[0420] Table 8 shows the center distance DG12 between the first lens group and the second lens group, the center distance DG23 between the second lens group and the third lens group, the center distance DG4 between the eighth lens and the optical filter according to the first mode to the third mode, the EFL according to each mode, the size of the EPD according to each mode, the optical axis distance (TD) of the lens according to each mode, the F number and the field of view according to each mode, and the BFL.

[0421] [Table 8]

[0422] project First Mode Second Mode The third mode DG12(mm) 4.708 1.982 0.450 DG23(mm) 1.876 1.074 1.234 DG4(mm) 1.553 4.997 6.353 EFL(M1F / M2F / M3F) 9.9 15.60 19.80 EPD (EPD1 / EPD2 / EPD3) 4.3797 5.1156 5.6503 TD (TD1 / TD2 / TD3) 19.7724 16.2437 14.8724 F-number 2.741 3.050 3.504 FOV(degree) 28.912 18.407 14.500 BFL (BFL1 / BFL2 / BFL3) 2.653 6.182 7.553

[0423] Tables 9 and 10 show the results of Equations 1 to 55 for the optical system 1000 of the second embodiment. Specifically, it can be seen that the optical system 1000 according to the second embodiment satisfies all of Equations 1 to 55. Therefore, the optical system 1000 can have good optical performance and excellent optical characteristics in both the central and peripheral portions of the FOV.

[0424] [Table 9]

[0425]

[0426]

[0427] [Table 10]

[0428]

[0429]

[0430] The optical system and the camera module according to the first and second embodiments disclosed above may satisfy at least one or two or more of Equations 1 to 30 and / or 31 to 55, or may satisfy all of them.

[0431] Figure 24 FIG is a diagram showing a camera module according to an embodiment applied to a mobile terminal. Figure 24 , the mobile terminal 1 may include the camera module 10 disclosed in the embodiments on the rear side. As another example, the mobile terminal 1 may include the camera module disclosed in the embodiments on the front side. The camera module 10 may have an image capture function. In addition, the camera module 10 may have at least one of an autofocus function, a zoom function, and an OIS function.

[0432] The camera module 10 can process a still image or video frame obtained by the image sensor 300 in a shooting mode or a video call mode. The processed image frame can be displayed on a display unit (not shown) of the mobile terminal 1 and stored in a memory (not shown). In addition, although not shown in the figure, the camera module can also be arranged on the front side of the mobile terminal 1. For example, the camera module 10 may include a first camera module 10A and a second camera module 10B. In this case, at least one of the first camera module 10A and the second camera module 10B may include the above-mentioned optical system 1000. Therefore, the camera module 10 can have a light and thin structure and can shoot objects at various magnifications.

[0433] The mobile terminal 1 may also include an autofocus device 31. The autofocus device 31 may include an autofocus function using a laser. The autofocus device 31 may be primarily used in situations where the autofocus function of the image using the camera module 10 degrades, for example, at close ranges of less than 10 meters or in a dark environment. The autofocus device 31 may include: a light-emitting unit including a vertical cavity surface emitting laser (VCSEL) semiconductor element; and a light-receiving unit that converts light energy into electrical energy, such as a photodiode. The mobile terminal 1 may also include a flash module 33. The flash module 33 may include an internally emitting light-emitting element. The flash module 33 may emit light in the visible light band. For example, the flash module 33 may emit white light or light of a color similar to white. However, this embodiment is not limited to this, and the flash module 33 may emit light of various colors. The flash module 33 may be operated by operating the mobile terminal's camera or by user control. 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.

[0434] The features, structures, effects, etc. described in the embodiments are included in at least one embodiment of the present invention and are not necessarily limited to one embodiment. In addition, the features, structures, effects, etc. shown in each embodiment can be combined or modified by a person skilled in the art of the embodiment for other embodiments. Therefore, the content related to such combination and modification should be interpreted as being included in the scope of the present invention. In addition, although the embodiments have been described above, this is merely an example and does not limit the present invention, and within the scope of the basic features of the present embodiment, a person skilled in the art of the present invention has given examples above. It can be seen that various modifications and applications that have not yet been made can be made. For example, the various components specifically shown in the embodiments can be implemented by modification. And the differences related to these modifications and applications should be interpreted as being included in the scope of the present invention defined in the appended claims.

Claims

1. An optical system comprising: The first lens group, the second lens group, and the third lens group are arranged along the optical axis from the object side to the sensor side, and each includes at least one lens. wherein the first lens group and the third lens group have negative refractive power, wherein the second lens group has positive refractive power, Wherein, the position of the first lens group is fixed, The number of lenses in the second lens group is smaller than the number of lenses in the first lens group. The second lens group and the third lens group are movable in the direction of the optical axis. wherein the optical system including the first to third lens groups has operation modes at different magnifications according to movement of at least one of the second lens group and the third lens group, wherein at least one of the second lens group and the third lens group includes a lens having the thickest center thickness among the lenses, The optical axis distance between the surface of the lens of the first lens group closest to the object side and the imaging surface of the image sensor is TTL, wherein the size of the entrance pupil diameter of the optical system at the highest magnification in the operating mode is EPD3, and Among them, the following formula is satisfied: 2 <TTL / EPD3<7。 2. The optical system according to claim 1, in, The optical axis distance between the lens closest to the image sensor in the third lens group and the image sensor varies according to the operation mode. The optical axis distance between the object-side surface of the lens closest to the object in the first lens group and the sensor-side surface of the lens closest to the image sensor in the third lens group varies according to the operation mode.

3. The optical system according to claim 1, in, The operation modes include wide-angle mode, Wherein, the wide-angle mode is Mode 1, Wherein, in the wide-angle mode, the optical axis distance between the first lens group and the second lens group is DG12, and the optical axis distance between the second lens group and the third lens group is DG23, Among them, the following formula is satisfied: 1 <Mode1(DG12 / DG23)<5。 4. The optical system according to any one of claims 1 to 3, in, The operation modes include telephoto mode, Among them, the telephoto mode is Mode3, Wherein, in the telephoto mode, the optical axis distance between the first lens group and the second lens group is DG12, and the optical axis distance between the second lens group and the third lens group is DG23, Among them, the following formula is satisfied: <Mode3(DG12 / DG23)<0.7。 5. The optical system according to any one of claims 1 to 3, in, The maximum distance between adjacent lenses according to the operation mode is Mode CG Max, The minimum distance between adjacent lenses according to the operation mode is Mode CG Min. Among them, the following formula is satisfied: 2 <Mode CG Max / Mode CG Min<8。 6. The optical system according to any one of claims 1 to 3, in, The number of lenses in the first lens group is 3, wherein, the number of lenses in the third lens group is 2 or 3, wherein, the absolute value of the focal length of the first lens group and the focal length of the third lens group is greater than the focal length of the second lens group.

7. The optical system according to claim 6, in, The optical system includes a wide-angle mode with a first effective focal length EFL1, a medium focal length mode with a second effective focal length EFL2, and a telephoto mode with a third effective focal length EFL3, wherein, the following formula is satisfied: EFL1 < ELF2 < EFL3.

8. The optical system according to claim 7, in, The field of view in the wide-angle mode is FOV1, the field of view in the medium focal length mode is FOV2, and the field of view in the telephoto mode is FOV3, and wherein, the following formula is satisfied: 8 degrees < FOV3 < FOV2 < FOV1 < 45 degrees.

9. The optical system according to any one of claims 1 to 3, in, The second lens group includes an object-side lens having an aspherical surface made of glass and having a biconvex shape, and a sensor-side lens having an aspherical surface made of plastic on the sensor side of the object-side lens.

10. An optical system, comprising: A first lens group having a first lens, a second lens, and a third lens; A second lens group having a fourth lens and a fifth lens; A third lens group having at least two lenses, wherein, the first lens group, the second lens group, and the third lens group are arranged from the object side toward the sensor side in the optical axis direction, wherein, the first lens has a positive diopter and the object-side surface has a convex shape, wherein, the third lens has a negative diopter and both surfaces have a concave shape, wherein, the fourth lens has a positive diopter and both surfaces have a convex shape, wherein, the last lens in the third lens group closest to the image sensor has a negative diopter, wherein, the second lens group and the third lens group move in the optical axis direction, and wherein, the optical axis distance between the last lens and the image sensor varies according to the operation mode.

11. The optical system according to claim 10, in, The first lens group has a negative diopter, wherein, the first lens has a meniscus shape convex toward the object side, wherein, the second lens has a meniscus shape convex toward the sensor side, wherein, the second lens and the fifth lens have a negative diopter.

12. The optical system according to claim 10 or 11, in, The fourth lens and the last lens have a refractive index less than 1.6, wherein, the fourth lens is made of glass, and the lenses other than the fourth lens are made of plastic.

13. The optical system according to claim 10 or 11, in, The maximum length of the first lens in a first direction perpendicular to the optical axis and the maximum length in a second direction perpendicular to the optical axis are different from each other, wherein, the maximum lengths of the first lens in the first direction and the second direction are the largest among the lenses, The difference between the center thickness and the edge thickness of the fifth lens is greater than 0.9, and The difference between the center thickness and the edge thickness of the sixth lens is greater than 0.

9.

14. The optical system according to claim 10 or 11, in, The optical axis distance between the first lens group and the second lens group and the optical axis distance between the second lens group and the third lens group are 0.2 mm or more and 8 mm or less, The optical axis distance from the center of the object-side surface of the fourth lens to the center of the sensor-side surface of the fifth lens is DG2. The optical axis distance from the object side surface of the first lens to the imaging surface of the image sensor is TTL. Among them, the following formula is satisfied: 3 <TTL / DG2<10。 15. A camera module comprising an optical system and a driving member, in, The optical system comprises the optical system according to claim 1 or 10, wherein the driving member moves at least one of the second lens group and the third lens group in an optical axis direction according to an operation mode of the optical system.

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