Optical system and camera module

Abstract

An optical system disclosed in an embodiment of the present invention includes: first to third lens groups arranged along an optical axis, each lens group including at least one lens, in which: the first lens group and the third lens group have positive refractive power, and the second lens group has negative refractive power; the position of the first lens group is fixed, and each of the second lens group and the third lens group moves along an optical axis according to an operation mode; the first lens closest to the object in the lenses of the first lens group has positive focal power; the optical axis distance of the second lens group is longer than that of the first lens group and the third lens group; the number of the lenses in the third lens group is smaller than that of the lenses in the first lens group; and the third lens group may have a meniscus lens protruding toward the sensor side and a meniscus shape protruding toward the object side.

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 laptop 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 / closer or zooming out / farther by increasing or decreasing the magnification of a remote object via a zoom lens. In addition, the camera module adopts image stabilization (IS) technology to correct or prevent image shaking caused by an unstable fixture or camera movement caused by the user's movement.

[0003] The most important element for the camera module to obtain an image is the imaging lens that forms the image. Recently, attention has been paid to high efficiency such as high image quality and high resolution, and research is being conducted on optical systems including multiple lenses to achieve this. For example, research is being conducted on using multiple imaging lenses with positive (+) and / or negative (-) refractive power to achieve a high-efficiency 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 optical systems including multiple lenses also increases, thereby increasing the thickness of cameras and mobile terminals including the optical systems.

[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 the lens or the lens group performs this function, the amount of movement of the lens or the lens group can 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 deterioration of aberration characteristics due to the movement of the lens or the lens group. Therefore, the problem is that when performing the zooming and autofocus (AF) functions, the optical characteristics deteriorate at a specific magnification. Therefore, a new optical system capable of solving the above problems is needed. Summary of the Invention Technical Problem

[0006] Embodiments of the present invention provide an optical system having improved optical characteristics. Embodiments provide an optical system and a camera module capable of taking pictures at various magnifications. Embodiments provide an optical system and a camera module having 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. Technical Solution

[0007] An optical system according to an embodiment of the present invention includes: a first lens group to a third lens group, arranged along an optical axis from an object toward a sensor side, each lens group including at least one lens, wherein the first lens group and the third lens group have a positive optical power, the second lens group has a negative optical power, the position of the first lens group is fixed, and each of the second lens group and the third lens group moves along the optical axis according to an operation mode, the first lens closest to the object in the first lens group has a positive optical power, the optical axis distance of the second lens group is greater than the optical axis distances of the first lens group and the third lens group, the number of lenses in the third lens group is less than the number of lenses in the first lens group, and the third lens group may include a lens having a meniscus shape convex toward the sensor side and a meniscus shape convex toward the object side.

[0008] According to an embodiment of the present invention, the lenses of the first lens group to the third lens group are made of plastic, and the number of lenses having a negative optical power in the first lens group to the third lens group is less than the number of lenses having a positive optical power.

[0009] According to an embodiment of the present invention, the optical axis distances of the first lens group to the third lens group are DG1, DG2, and DG3, and the following mathematical expressions may be satisfied: 0.5 < DG1 / DG2 < 1 and 0.8 < DG1 / DG3 < 1.

[0010] According to an embodiment of the present invention, a lens having the largest absolute value of focal length among the first lens group to the third lens group may be disposed within the third lens group. The optical axis distance of the third lens group is DG3, and the optical axis distance between the surface of the lens closest to the object side of the first lens group and the imaging surface of the image sensor is TTL, and the following mathematical formula may be satisfied: 2 < TTL / (DG2 + DG3) < 5.

[0011] 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 varies according to the operation mode, and the operation modes of the optical system may include a wide-angle mode, a medium telephoto mode, and a telephoto mode.

[0012] According to an embodiment of the present invention, 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, and 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 may be at least 0.2 mm or greater and at most 8 mm or less.

[0013] According to an embodiment of the present invention, the wide-angle mode is Md1. 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 mathematical formula may be satisfied: 1 < Md1(DG12 / DG23) < 5. The telephoto mode is Md3. 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 mathematical formula may be satisfied: 0 < Md3(DG12 / DG23) < 0.7.

[0014] According to an embodiment of the present invention, the maximum distance between adjacent lenses according to the operation mode is Md_CG_Max, and the minimum distance between adjacent lenses according to the operation mode is Md_CG_Min, and the following mathematical formula may be satisfied: 2 < Md_CG_Max / Md_CG_Min < 8.

[0015] According to an embodiment of the present invention, the number of lenses in the first lens group is greater than the number of lenses in the second lens group, and the absolute value of the focal length of the first lens group may be greater than twice the focal length of the second lens group. The effective focal length in the wide-angle mode of the optical system is FMd1, and the focal length of the first lens is F1, and the following mathematical formula may be satisfied: 5 < F1 / Fmd1 < 13.

[0016] According to an embodiment of the present invention, the effective focal length in the telephoto mode of the optical system is FMd3, and it can satisfy the following mathematical formula: 0 < F1 / Fmd3 < 0.6. The field of view in the wide-angle mode is FOV1, the field of view in the mid-telephoto mode is FOV2, and the field of view in the telephoto mode is FOV3, and it can satisfy the following mathematical formula: 8° < FOV3 < FOV2 < FOV1 < 45°.

[0017] The optical system according to an embodiment of the present invention includes: a first lens group having a first lens to a third lens; a second lens group having a fourth lens and a fifth lens; and a third lens group having a sixth lens and a seventh lens, wherein the first lens group, the second lens group, and the third lens group are arranged along the optical axis direction from the object toward the sensor, the first lens has a positive refractive power and has a convex object-side surface on the optical axis, the third lens has a negative refractive power and has a biconcave shape on the optical axis, the fifth lens and the sixth lens have refractive powers of opposite signs and have a meniscus shape convex on the sensor side, the second lens group and the third lens group move in the optical axis direction, and the optical axis distance between the seventh lens and the image sensor varies according to the operation mode, the number of lenses having a refractive index exceeding 1.60 among the first lens to the seventh lens is greater than the number of lenses having a refractive index less than 1.60, the refractive index of the second lens is Nd2, and it can satisfy the mathematical formula: 1.65 < Nd2.

[0018] According to an embodiment of the present invention, the first lens group and the third lens group may have a negative (-) refractive power, and the second lens and the fourth lens may have a positive refractive power. The fourth lens and the seventh lens may have a refractive index less than 1.6. The lens surface having the largest absolute value of the curvature radius of the object-side surface and the sensor-side surface of each of the first lens to the seventh lens may be the object-side surface of the third lens.

[0019] According to an embodiment of the present invention, the effective length of the first lens is the largest among the lenses, and the maximum length of the first lens in the second direction perpendicular to the optical axis and the maximum length in the first direction may be different from each other. The effective length of the largest lens surface among the first lens to the seventh lens is CA_Max, and half of the diagonal length of the image sensor is ImgH, and it can satisfy the following mathematical formula: 1 < CA_Max / ImgH < 3.

[0020] The camera module according to an embodiment of the present invention includes: an image sensor; an optical system; and a driving member for moving at least one of the plurality of lens groups of the optical system in the optical axis direction, wherein the optical system includes the above optical system, and the driving member can move the position of each of the second lens group and the third lens group of the optical system in the optical axis direction. Advantageous Effects

[0021] The optical system and camera module according to the embodiment have various magnifications and can have excellent optical characteristics when providing various magnifications. In detail, the embodiment can control the movement distance of each of the mobile lens groups to have various magnifications and provide an autofocus (AF) function for the object. The optical system and camera module according to the embodiment can compensate for the aberration characteristics of multiple lens groups or complement each other's aberration characteristics that change due to movement. Therefore, the optical system according to the embodiment can minimize or prevent changes in chromatic aberration and aberration characteristics that occur when the magnification changes.

[0022] The optical system and camera module according to the embodiment can control the effective focal length (EFL) by moving only some of the lens groups in the plurality of lens groups, and can minimize the moving distance of the moving lens group. Therefore, the optical system can reduce the moving distance of the moving 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 moving 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 plurality of lens groups have space for structural arrangement.

[0023] The optical system and camera module according to embodiments can adjust 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 magnification changes to achieve multiple focal lengths, the optical system can maintain a constant TTL value and can be applied to a camera module for linear zoom. Consequently, the optical system and camera module including the optical system can have a thinner structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a configuration diagram of an optical system and a camera module having the same according to an embodiment of the present invention.

[0025] Figure 2 yes Figure 1 An example of a first mode change of the optical system.

[0026] Figure 3 yes Figure 1 and Figure 2 An example of a third mode change in an optical system.

[0027] Figure 4 is Figure 1 The optical system has a configuration of a reflecting mirror.

[0028] Figure 5 is a table of lens data of an optical system according to an embodiment of the present invention.

[0029] Figure 6 : is a table showing aspheric coefficients of lenses of the optical system according to the embodiment of the present invention.

[0030] Figure 7 is a graph illustrating relative illuminance according to positions in a wide-angle mode, a mid-focus mode, and a telephoto mode according to an embodiment of the present invention.

[0031] Figure 8 is a graph of diffraction MTF in the optical system of the first mode (wide-angle mode) according to the embodiment of the present invention.

[0032] Figure 9 : is a graph of diffraction MTF in the optical system in the second mode (middle focus mode) according to the embodiment of the present invention.

[0033] Figure 10 is a graph of diffraction MTF in the optical system of the third mode (telephoto mode) according to the embodiment of the present invention.

[0034] Figure 11 : are diagrams showing aberration characteristics in the optical system according to the first mode of the embodiment of the present invention.

[0035] Figure 12 : are diagrams showing aberration characteristics in the optical system according to the second mode of the embodiment of the present invention.

[0036] Figure 13 : are diagrams showing aberration characteristics in the optical system according to the third mode of the embodiment of the present invention.

[0037] Figure 14 is a diagram illustrating a camera module according to an embodiment of the present invention applied to a mobile terminal. DETAILED DESCRIPTION

[0038] Hereinafter, preferred 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 some embodiments to be described, and can be implemented in various other forms, and one or more components can be selectively combined and replaced for use within the scope of the technical spirit of the present invention. In addition, unless otherwise defined and clearly described, the terms (including technical examples and scientific terms) used in the embodiments of the present invention can be interpreted with the meaning that ordinary technicians in the field to which the present invention belongs can generally understand, and commonly used terms (such as terms defined in dictionaries) should be able to interpret their meanings in consideration of the contextual meaning of the relevant technology.

[0039] The terms used in the embodiments of the present invention are used to explain the embodiments and are not intended to limit the present invention. In this specification, unless otherwise specifically stated in a phrase, the singular form may also include the plural form, and in the case of stating at least one (or one or more) of A and (with) B, C, it may include one or more of all combinations that can be combined with A, B and C. When describing the components of the embodiments of the present invention, terms such as first, second, A, B, (a) and (b) may be used. Such terms are only used to distinguish a component from other components and may not be determined by the properties, order or procedure of the corresponding constituent elements by the terms. And when describing a component as "connected", "coupled" or "engaged" to another component, the description may include not only direct connection, coupling or engagement to another component, but also "connection", "coupling" or "engagement" between the component and the other component through other components. In addition, when described as being formed or arranged "above (upper)" or "below (lower)" of each component, the description may include not only the situation where the two components are in direct contact with each other, but also the situation where one or more other components are formed or arranged between the two 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. Several embodiments described below can be combined with each other unless it is specifically stated that they cannot be combined with each other. In addition, unless otherwise explicitly stated, the description of other embodiments can also apply to the parts omitted in the description of any embodiment among the several embodiments.

[0040] 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 (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 optical axis direction. 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 of ​​the lens through which the incident light 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.

[0041] Figure 1 is a configuration diagram of a first mode of a camera module or an optical system according to an embodiment of the present invention, Figure 2 It is from Figure 1 An example of a change from the first mode to the second mode of an optical system, Figure 3 It is from Figure 1 and Figure 2Example of change of the optical system to the third mode, Figure 4 is Figure 1 The optical system has a configuration of a reflector, Figure 5 is a table of lens data of an optical system according to an embodiment of the present invention, Figure 6 is a table showing aspheric coefficients of lenses of an optical system according to an embodiment of the present invention, Figure 7 is a diagram illustrating relative illuminance according to positions in a wide-angle mode, a mid-focus mode, and a telephoto mode in a camera module according to an embodiment of the present invention, Figure 8 is a graph of diffraction MTF in the optical system according to the first mode (wide-angle mode) of the embodiment of the present invention, Figure 9 is a graph of diffraction MTF in the optical system in the second mode (middle focus mode) according to the embodiment of the present invention, Figure 10 is a graph of diffraction MTF in the optical system according to the third mode (telephoto mode) of the embodiment of the present invention, Figure 11 : is a diagram showing aberration characteristics in the optical system according to the first mode of the embodiment of the present invention, Figure 12 are diagrams showing aberration characteristics in the optical system according to the second mode of the embodiment of the present invention, and Figure 13 : are diagrams showing aberration characteristics in the optical system according to the third mode of the embodiment of the present invention.

[0042] refer to Figures 1 to 6 According to an embodiment, the optical system 1000 may include a plurality of lens groups G1, G2, and G3. Specifically, the plurality of lens groups G1, G2, and G3 may include at least two lens groups that are movable in the direction of the optical axis OA and at least one lens group that is fixed in position. The plurality of lens groups G1, G2, and G3 may include a lens group fixed on the object side and a lens group movable on the sensor side. The plurality of movable lens groups may include an object-side lens group and a sensor-side lens group.

[0043] The lens group fixed on the object side can be defined as the first lens group G1, the lens group moving on the object side can be defined as the second lens group G2, and the lens group moving on the sensor side can be defined as the third lens group G3. The second lens group G2 can be disposed between the first lens group G1 and the third lens group G3. The first lens group G1 refracts incident light toward the second lens group G2, the second lens group G2 moves along the optical axis OA and changes the zoom magnification (focal length), and the third lens group G3 moves along the optical axis OA and can adjust the focal position on the image plane of the image sensor 300. The optical system 1000 can include the first lens group G1, the second lens group G2, and the third lens group G3, arranged sequentially along the optical axis OA from the object toward the sensor. The optical system 1000 can include the image sensor 300 on the sensor side of the third lens group G3. The first lens group G1 can include the lens closest to the object side, and the third lens group G3 can include the lens closest to the sensor side. Each of the first to third lens groups G1, G2, and G3 can have positive (+) or negative (-) refractive power. For example, the lens group with positive refractive power can be smaller than the lens group with negative refractive power. The first lens group G1 can have a refractive power of the opposite sign to the refractive power of the second lens group G2. For example, the first lens group G1 can have a negative (-) refractive power, and the second lens group G2 can have a positive (+) refractive power. The second lens group G2 can have a refractive power of the opposite sign to the refractive power of the third lens group G3. For example, the second lens group G2 can have a positive (+) refractive power, and the third lens group G3 can have a negative (-) refractive power. The absolute value of the focal length of the third lens group G3 can be greater than the absolute value of the focal lengths of the first lens group G1 and the second lens group G2. For example, the absolute value of the focal length of the first lens group G1 can be 1.5 times or more of the focal length of the second lens group G2. Therefore, the first lens group G1 can disperse the incident light. The focal length of the second lens group G2 can be smaller than the absolute value of the focal length of the third lens group G3. The absolute value of the focal length of the third lens group G3 may be greater than the absolute value of the focal length of the first lens group G1. The optical power of the first and third lens groups (G1, G3) may have negative optical power, and the optical power of the second lens G2 may have positive optical power. Optical power is the reciprocal of the focal length value. 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 equal to or less than the number of lenses in the third lens group G3. For example, the number of lenses in the second and third lens groups G2 and G3 may be the same. The number of lenses in the first lens group G1 may be greater than the number of lenses in the second lens group G2 and the third lens group G3. The number of lenses in the first lens group G1 may include at least three lenses for adjusting the amount of incident light, refractive power, and chromatic aberration. The third lens group G3 may include at least two lenses. The number of lenses in the first to third lens groups G1, G2, and G3 may be two or more.As another example, the optical system may further include at least one lens whose position is fixed between the third lens group G3 and the image sensor 300. Therefore, the optical system 1000 may include six or more lenses and nine or less lenses.

[0044] Since the first and second lens groups G1 and G2 have refractive powers of opposite signs (+, -), aberrations can be corrected, and since the second and third lens groups G2 and G3 have refractive powers of opposite signs (+, -), aberrations can be corrected. The absolute value of the focal length of each of the first to third lens groups G1, G2, and G3 can also decrease in the order of the third lens group G3, the first lens group G1, and the second lens group G2. The first lens group G1 is fixed in place, the second lens group G2 and the third lens group G3 are moved in the direction of the optical axis OA (M1, M2), and the optical system 1000 can provide various magnifications by moving at least two lens groups. Below, the first to third lens groups G1, G2, and G3 will be described in more detail. The first lens group G1 may include at least two lenses having refractive powers of opposite signs, and at least two lenses may have refractive powers of the same sign. For example, the first lens group G1 may include three lenses. The first lens group G1 may have a larger number of lenses having positive refractive power than lenses having negative refractive power.

[0045] The first lens group G1 may include multiple lenses, and the multiple lenses may be spaced apart at predetermined intervals along the optical axis OA. Specifically, the center distances between the multiple lenses 101, 102, and 103 included in the first lens group G1 may be fixed according to the operating mode described below. For example, the center distances between adjacent lenses 101, 102, and 103 in the first lens group G1 may not vary depending on the operating mode and may be spaced apart at predetermined intervals. Hereinafter, the center distance between lenses may refer to the optical axis distance between adjacent lenses.

[0046] The second lens group G2 may include multiple lenses, including lenses 104 and 105 having opposite refractive powers. The multiple lenses 104 and 105 in the second lens group G2 may have a set spacing. Specifically, the center distance between adjacent lenses 104 and 105 in the second lens group G2 may be fixed according to the operating mode described below. The third lens group G3 may include multiple lenses, including lenses 106 and 107 having opposite refractive powers. The multiple lenses 106 and 107 in the third lens group G3 may have a set spacing. Specifically, the center distance between the multiple lenses 106 and 107 in the third lens group G3 may be constant, even when the operating mode described below changes. For example, the center distance between adjacent lenses 106 and 107 may be constant and not vary depending on the operating mode. The last lens in the third lens group G3 may have a set spacing from the image sensor 300 and / or the optical filter 500, and this spacing may vary depending on the operating mode.

[0047] The optical system 1000 may include first to seventh lenses. The first lens group G1 may include first to third lenses 101, 102, and 103, and the second lens group G2 may include fourth and fifth lenses 104 and 105. In addition, the third lens group G3 may include sixth and seventh lenses 106 and 107. The first to seventh lenses and the image sensor 300 may be sequentially arranged along the optical axis OA of the optical system 1000.

[0048] At least one lens in the first lens group G1 may have different effective lengths in a first direction X and a second direction Y, which are orthogonal to the optical axis OA. Lenses in the first lens group G1 having different effective lengths in the first direction X and the second direction Y may be non-circular lenses; for example, the effective length in the second direction Y may be shorter than the effective length in the first direction X. One, two, or more of the first to third lenses 101, 102, and 103 may have an effective length in the second direction Y on the object-side surface that is shorter than the effective length in the first direction X. At least one lens in the second lens group G2 may have different effective lengths in the first direction X and the second direction Y, which are orthogonal to the optical axis OA. Lenses in the second lens group G2 having different effective lengths in the first direction X and the second direction Y may be non-circular lenses; for example, the effective length in the second direction Y may be shorter than the effective length in the first direction X. One or both of the fourth lens 104 and the fifth lens 105 may have an effective length in the second direction Y on the object-side surface that is shorter than the effective length in the first direction X.

[0049] At least one lens in the third lens group G3 may have different lengths in the second direction Y and the first direction X, which are perpendicular to the optical axis OA. Lenses in the first lens group G1 having different effective lengths in the first direction X and the second direction Y may be non-circular lenses. For example, the effective length in the second direction Y may be smaller than the effective length in the first direction X. Specifically, among the lenses in the lens section 100, the first lens 101 having the largest effective length may have an effective length in the first direction X that is longer than its effective length in the second direction Y. The second lens 102 may have an effective length in the first direction X that is longer than its effective length in the second direction Y. The fourth lens 104 may have an effective length in the first direction X that is longer than its effective length in the second direction Y. The effective lengths of the lenses in the first lens group G1 may gradually decrease from the object side toward the sensor side. The effective lengths of the lenses in the second lens group G2 may gradually decrease from the object side toward the sensor side. The effective lengths of the lenses in the third lens group G3 may increase from the object side toward the sensor side. The effective length of each lens is the average of the effective lengths of the object-side and sensor-side surfaces of each lens.

[0050] The optical system 1000 according to an embodiment can have improved assembly characteristics through the use of non-circular lenses and has a mechanically stable form. Furthermore, the optical system 1000 can significantly reduce the movement distances DG12, DG23, and DG4 of the movable lens groups G2 and G3 and provide a variety of magnifications. Furthermore, since the lenses having a large effective length in the second direction Y are configured as a shape with two sides cut in the second direction Y, the height or thickness of the optical system 1000 and the camera module in the second direction Y can be reduced. Thus, the increase in thickness of the device having the slim optical system 1000 and camera module can be suppressed. Each lens in the lens section 100 can include an active area and an inactive area. The active area is an area with an effective diameter and can be the area through which light incident on each of the first to seventh lenses 101 to 107 passes. The active area can be the area where the incident light is refracted to achieve the optical characteristics. The inactive area can be arranged around the active area. The inactive area can be an area where light does not enter. In other words, the inactive area can be an area unrelated to the optical characteristics. Alternatively, the inactive area can be an area fixed to the lens barrel (not shown) that houses the lenses. The image sensor 300 can detect light. The image sensor 300 can detect light that sequentially passes through the lens portion 100 (for example, the first to seventh lenses 101-107). The image sensor 300 can include a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor).

[0051] The optical system 1000 may further include an optical filter 500. The optical filter 500 may be disposed between the lens portion 100 and the image sensor 300. The optical filter 500 may also be disposed between the image sensor 300 and the third lens group G3. For example, the optical filter 500 may be disposed between the last lens 107 and the image sensor 300. The optical filter 500 may include at least one of an infrared filter and a cover glass. The optical filter 500 may pass light of a predetermined wavelength band and filter light of a different wavelength band. When the optical filter 500 includes an infrared filter, it may block radiant heat emitted from external light from being transmitted to the image sensor 300. The optical filter 500 may transmit visible light and reflect infrared light. The optical system 1000 may include an aperture stop (not shown). The aperture stop may control the amount of light incident on the optical system 1000. The aperture stop may be disposed on the periphery of the object-side surface of the fourth lens 104. An aperture stop can be provided between two lenses selected from the first through seventh lenses 101-107. For example, the aperture stop can be provided on the periphery between the third lens 103 and the fourth lens 104. The aperture stop can be provided on the periphery of the sensor-side surface of the third lens 103 or on the periphery of the object-side surface of the fourth lens 104. Alternatively, at least one of the first through seventh lenses 101-107 can function as an aperture stop. For example, the exterior of the object-side surface or sensor-side surface of a lens selected from the first through seventh lenses 101-107 can function as an 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 an aperture stop.

[0052] The object-side and sensor-side surfaces of the first through seventh lenses 101-107 may be aspherical. The first through seventh lenses 101-107 may be made of plastic. Alternatively, at least one of the first through third lenses 101, 102, and 103 may be made of glass.

[0053] like Figure 4As shown, the optical system 1000 may further include an optical path changing member 400. 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 a 90-degree angle to change the light's first path OA1. The first path OA1 may be in the direction of the optical axis of the optical system. The optical path changing member 400 may be positioned closer to the object side than the multiple lenses. That is, when the optical system 1000 includes the optical path changing member 400, the optical path changing member 300, the first lens 101 to the seventh lens 107, the optical filter 500, and the image sensor 300 may be arranged in sequence from the object side toward the sensor.

[0054] The optical path changing member 400 can change the path of light incident from the outside in 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 the second direction Y to a first path OA1 in the third direction Z, where the multiple lenses are arranged. When 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. In detail, when the optical system 1000 includes the optical path changing member 400, light incident in the 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 multiple lenses can have a thinner thickness within the device, thereby reducing the height of the device.

[0055] When the optical system 1000 does not include an optical path altering member, the multiple lenses can be arranged to extend in a direction Y perpendicular to the surface of the device. Therefore, the optical system 1000 including multiple lenses has a high height in a direction perpendicular to the surface of the device (the first direction), which can make it difficult to make the optical system 1000 and the device including the optical system thin. However, when the optical system 1000 includes the optical path altering member 400, the multiple lenses 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 used in a foldable camera. Therefore, the optical system 1000 including the lens section 100 can have a low height in a direction perpendicular to the surface of the device. Therefore, a camera including the optical system 1000 can have a thin thickness within the device, and the thickness of the device can also be reduced. As another example, the optical path altering member can be provided between two lenses of the lens section 100, or further provided between the last lens adjacent to the image sensor 300 and the image sensor 300. As another example, multiple optical path altering members can be provided. Specifically, a plurality of optical path changing members may be provided between the object and the image sensor 300. For example, the plurality of optical path changing members may include a first optical path changing member disposed on a side closer to the object than the plurality of lenses, and a second optical path changing member disposed between the last lens and the image sensor 300. Thus, the optical system 1000 may have various shapes and heights depending on the camera to which it is applied, and may have improved optical performance.

[0056] refer to Figures 1 to 3 , the first lens 101 may be positioned closest to the object among the plurality of lenses, and the seventh lens 107 may be positioned closest to the image sensor 300. For ease of explanation, the center thicknesses 101-107 are CT1 to CT7, the edge thicknesses are ET1 to ET7, the Abbe numbers are Vd1 to Vd7, the refractive indices are Nd1 to Nd7, the average values ​​of the effective lengths are CA1 to CA7, and the focal lengths may be defined as F1 to F7 of each of the first to seventh lenses.

[0057] The first lens 101 may have a positive (+) refractive power on the optical axis OA. The first lens 101 may include a plastic or glass material, and may be, for example, a plastic material. The first lens 101 may include a first surface S1 on the object side and a second surface S2 on the sensor side. The first surface S1 may have a convex shape on the optical axis OA, and the second surface S2 may have a concave shape on the optical axis OA. That is, the first lens 101 may have a meniscus shape that is convex toward the object side on the optical axis OA. Alternatively, the first lens 101 may have a shape in which both sides are convex on the optical axis. Alternatively, the first lens 101 may have a meniscus shape that is convex toward the sensor side. At least one of the first surface S1 and the second surface S2 may be aspherical. For example, both the first surface S1 and the second surface S2 may be aspherical. The aspherical coefficients of the first surface S1 and the second surface S2 may be expressed as Figure 6 L1S1 and L1S2 in.

[0058] The first lens 101 can have the longest effective length among all lenses, i.e., the maximum effective length. Specifically, the effective length of the first surface S1 of the first lens 101 in the second direction Y can be the longest among all lenses. The average effective length of the first surface S1 and the second surface S2 of the first lens 101 in the second direction Y can be greater than the average effective length of the object-side and sensor-side surfaces of the second through seventh lenses 102 through 107. 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 between the optical axis and the ends of the effective area.

[0059] The second lens 102 can have positive (+) or negative (-) refractive power on the optical axis OA, for example, it can have positive refractive power. The second lens 102 can be made of plastic or glass, for example, it can be made of plastic. The second lens 102 can include a third surface S3 defined as an object-side surface and a fourth surface S4 defined as a sensor-side surface. The third surface S3 can have a convex shape on the optical axis OA, and the fourth surface S4 can have a convex shape on the optical axis OA. The second lens 102 can have a shape in which both surfaces are convex on the optical axis OA. Alternatively, the third surface S3 can have a convex shape on the optical axis OA, and the fourth surface S4 can have a concave shape. Alternatively, the third surface S3 can have a concave shape on the optical axis OA, and the fourth surface S4 can have a convex shape on the optical axis OA. In contrast, the third surface S3 can have a concave shape on the optical axis OA, and the fourth surface S4 can have a convex shape on the optical axis OA. At least one of the third surface S3 and the fourth surface S4 of the second lens 102 can be aspherical. For example, both the third surface S3 and the fourth surface S4 may be aspherical. The aspherical coefficients of the third surface S3 and the fourth surface S4 may be given by Figure 6The third surface S3 and the fourth surface S4 may be arranged to have no critical point from the optical axis to the end of the effective area, or at least one of the third surface S3 and the fourth surface S4 may have a critical point.

[0060] The third lens 103 may have positive (+) or negative (-) refractive power on the optical axis OA, for example, may have negative (-) refractive power. The third lens 103 may include a plastic or glass material, and may be, for example, a plastic material. The third lens 103 may include a fifth surface S5 defined as an object-side surface and a sixth surface S6 defined as a sensor-side surface. The fifth surface S5 may have a concave shape on the optical axis OA, and the sixth surface S6 may have a concave shape 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. Alternatively, the fifth surface S5 may have a concave shape on the optical axis OA, and the sixth surface S6 may have a convex shape. Alternatively, the fifth surface S5 and the sixth surface S6 may have a convex shape on the optical axis OA. At least one of the fifth surface S5 and the sixth surface S6 of the third lens 103 may be aspherical. For example, both the fifth surface S5 and the sixth surface S6 may be aspherical. The aspherical coefficients of the fifth surface S5 and the sixth surface S6 may be given by Figure 6 The fifth surface S5 and the sixth surface S6 may be configured to have no critical point from the optical axis to the end of the effective area. As another example, at least one of the fifth surface S5 and the sixth surface S6 may have a critical point from the optical axis to the end of the effective area.

[0061] The second lens 102 and the third lens 103 can compensate for chromatic aberration occurring in the first lens 101. The refractive index of the second lens 102 can be greater than 1.6. The second lens 102 can be one of the lenses with the highest refractive index. The radius of curvature of the sixth surface S6 of the third lens 103 can be the smallest of the radii of curvature of the object-side and sensor-side surfaces of each lens 101, 102, and 103 in the first lens group G1. The absolute value of the radius of curvature of the sixth surface S6 of the third lens 103 can be the largest of the lenses. The absolute value of the radius of curvature of the fifth surface S5 of the third lens 103 can be the largest of the radii of curvature of the object-side and sensor-side surfaces of each lens 101, 102, and 103 in the first lens group G1. Therefore, since the first lens group G1 controls the dispersion of light provided to the second lens group G2, the size of the second lens group G2 can be reduced. The variable size of the center distance DG12 between the first and second lens groups G1 and G2 can be set by the radius of curvature of the sixth surface S6 of the third lens 103 according to the operating mode.

[0062] The fourth lens 104 may have a positive (+) refractive power on the optical axis OA. The fourth lens 104 may include a plastic or glass material, and may be, for example, a plastic material and have a refractive index less than 1.6. The fourth lens 104 may include a seventh surface S7 defined as an object-side surface and an eighth surface S8 defined as a sensor-side surface. The seventh surface S7 may have a convex shape on the optical axis OA, and the eighth surface S8 may have a convex shape on the optical axis OA. That is, the fourth lens 104 may have a shape in which both sides are convex on the optical axis OA. Alternatively, the seventh surface S7 may have a convex shape on the optical axis OA, and the eighth surface S8 may have a concave shape 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 of the seventh surface S7 and the eighth surface S8 of the fourth lens 104 may be aspherical. For example, both the seventh surface S7 and the eighth surface S8 may be aspherical. The aspherical coefficients of the seventh surface S7 and the eighth surface S8 may be given by Figure 6 The seventh surface S7 and the eighth surface S8 may be arranged so as to have no critical point from the optical axis to the end of the effective area.

[0063] The fifth lens 105 may have a positive (+) or negative (-) refractive power on the optical axis OA. The fifth lens 105 may have a negative refractive power having an opposite sign to the refractive power of the fourth lens 104 on the optical axis OA. The fifth lens 105 may include a plastic or glass material, and may be, for example, a plastic material. The fifth lens 105 may include a ninth surface S9 defined as an object-side surface and a tenth surface S10 defined as a sensor-side surface. The ninth surface S9 may have a concave shape on the optical axis OA, and the tenth surface S10 may have a convex shape on the optical axis OA. That is, the fifth lens 105 may have a meniscus shape that bulges toward the sensor on the optical axis OA. At least one of the ninth surface S9 and the tenth surface S10 may be aspherical. For example, both the ninth surface S9 and the tenth surface S10 may be aspherical. The aspherical coefficients of the ninth surface S9 and the tenth surface S10 may be given by Figure 6 L5S1 and L5S2 are represented. The ninth surface S9 and the tenth surface S10 of the fifth lens 105 can be arranged to have no critical point from the optical axis to the end of the effective area. 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. That is, the fifth lens 10 can have a shape with two surfaces convex on the optical axis OA. Alternatively, the ninth surface S9 can have a concave shape on the optical axis OA, and the tenth surface S10 can have a concave shape on the optical axis OA. Alternatively, the ninth surface S9 can have a convex shape on the optical axis OA, and the tenth surface S10 can have a concave shape on the optical axis OA.

[0064] The fourth lens 104 has a biconvex shape, and its center thickness CT4 can be thicker than its edge thickness ET4, for example, at least twice the edge thickness ET4. Thus, the distance between the fourth lens 104 and the fifth lens 105 can be reduced. The fourth lens 104 can be one of the lenses with the largest Abbe number, or can have an Abbe number of 45 or greater. The difference in Abbe number between the fourth lens 104 and the fifth lens 105 can be greater than 20 or greater than 25, and can be at most 55 or less. Thus, the second lens group G2 can minimize chromatic aberration caused by position changes depending on the operating mode.

[0065] The sixth lens 106 may be an (n-1)th lens. The sixth lens 106 may have positive (+) or negative (-) refractive power along the optical axis OA, for example, positive refractive power. The sixth lens 106 may be made of plastic or glass, and may be made of plastic, for example. The sixth lens 106 may include an eleventh surface S11, defined as an object-side surface, and a twelfth surface S12, defined as a sensor-side surface. The eleventh surface S11 may have a concave shape along the optical axis OA, and the twelfth surface S12 may have a convex shape along the optical axis OA. That is, the sixth lens 106 may have a meniscus shape that convexly projects toward the sensor side along the optical axis OA. Thus, the eleventh surface S11 may have a convex shape along the optical axis OA, and the twelfth surface S12 may have a convex shape along the optical axis OA. That is, the sixth lens 106 may have a biconvex shape along the optical axis OA. Thus, the eleventh surface S11 may have a concave shape along the optical axis OA, and the twelfth surface S12 may have a concave shape along the optical axis OA. In this way, 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 of the eleventh surface S11 and the twelfth surface S12 of the sixth lens 106 may be aspherical. For example, both the eleventh surface S11 and the twelfth surface S12 may be aspherical. The aspherical coefficients of the eleventh and twelfth surfaces (S11, S12) may be given by Figure 6 denoted by L6S1 and L6S2 in FIG. The eleventh surface S11 and the twelfth surface S12 can be configured to have no critical point from the optical axis to the end of the effective area. The sixth lens 106 can be one of the lenses having the thickest center thickness CT6 among the center thicknesses of the lenses. That is, at least one or both of the center thicknesses CT5 and CT6 of the fifth lens 105 and the sixth lens 106 can have the thickest thickness among the lenses. Therefore, since the center thickness CT6 of the sixth lens 106 is configured thicker, the number of lenses in the third lens group G3 can be reduced.

[0066] The seventh lens 107 may be an n-th lens. The seventh lens 107 may have positive (+) or negative (-) refractive power on the optical axis OA, and may have negative refractive power. The refractive power of the seventh lens 107 has a sign opposite to that of the refractive power of the sixth lens 106 to improve chromatic aberration. The seventh lens 107 may be made of plastic or glass, and may be, for example, a plastic material. The seventh lens 107 may include a thirteenth surface S13 defined as an object-side surface and a fourteenth surface S14 defined as a sensor-side surface. The thirteenth surface S13 may have a convex shape on the optical axis OA, and the fourteenth surface S14 may have a concave shape on the optical axis OA. That is, the seventh lens 107 may have a meniscus shape that bulges toward the object on the optical axis OA. As another example, the thirteenth surface S13 may have a convex shape on the optical axis OA, and the fourteenth surface S14 may have a convex shape on the optical axis OA. Alternatively, the thirteenth surface S13 may have a concave shape along the optical axis OA, and the fourteenth surface S14 may have a convex shape along the optical axis OA. That is, the seventh lens 107 may have a meniscus shape that convexly projects toward the sensor along the optical axis OA. Alternatively, the thirteenth surface S13 may have a concave shape along the optical axis OA, and the fourteenth surface S14 may have a concave shape along the optical axis OA. That is, the seventh lens 107 may have a biconcave shape along the optical axis OA.

[0067] The fifth lens 105 and the sixth lens 106 have refractive powers of opposite signs, and the difference in Abbe number can be set to 10 or less. Therefore, the fifth lens 105 and the sixth lens 106 can compensate for 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 perform the achromatic function.

[0068] At least one of the thirteenth surface S13 and the fourteenth surface S14 of the seventh lens 107 may be aspherical. For example, both the thirteenth surface S13 and the fourteenth surface S14 may be aspherical. The aspherical coefficients of the thirteenth surface S13 and the fourteenth surface S14 may be given by Figure 6L7S1 and L7S2 are represented. The thirteenth surface S13 and the fourteenth surface S14 can be arranged to have no critical point between the optical axis and the end of the effective area. As another example, at least one of the thirteenth surface S13 and the fourteenth surface S14 of the seventh lens 107 can have a critical point between the optical axis and the end of the effective area. This critical point is a point where the sag value changes in trend. That is, the critical point is a point on the lens surface where the sag value increases and then decreases, or where the sag value decreases and then increases. The sag value is the optical axis distance between a line perpendicular to the center of each lens surface and the lens surface. The sag value has a positive value at a position on the sensor side relative to the center of each lens surface and a negative value at a position on the object side relative to the center of each lens surface. The sixth lens 106 and the seventh lens 107 have refractive powers of opposite signs, and the difference in Abbe numbers can be set to 20 or greater, which can control chromatic aberration. Therefore, chromatic aberration changes caused by position changes due to the movement of the third lens group G3 can be minimized, and the achromatic function can be performed.

[0069] The center thickness CT7 of the seventh lens 107 can be thinner than the edge thickness ET7. Therefore, the difference between the center and edge thicknesses of the seventh lens 107, along with the concave shape of the fourteenth surface S14, can refract incident light toward the periphery of the image sensor 300. The third lens group G3 can be closest to the image sensor 300 among the multiple lens groups G1, G2, and G3. The third lens group G3 can be movable in the optical axis direction, and the optical axis distance BFL between the seventh lens 107 and the image sensor 300 can vary depending on the operating mode. Here, BFL is the optical axis distance from the center of the sensor-side surface of the seventh lens 107 to the image sensor 300.

[0070] The third lens group G3 may control the chief ray angle (CRA). Specifically, the CRA of the optical system 1000 according to an embodiment may be less than about 20 degrees, and the seventh lens 107 of the third lens group G3 may correct the chief ray angle of light incident on the image sensor 300 according to each operation mode.

[0071] The camera module according to an embodiment of the present invention may include the above-mentioned optical system 1000. The camera module may be configured so that two lens groups G2 and G3 on the sensor side of the plurality of lens groups G1, G2, and G3 included in the optical system 1000 can move 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 on the outer side of the second lens group G2 and the outer side of each of the third lens group G3, and may move in the direction of the optical axis OA according to an operating mode. The operating mode may include a first mode moving at a first magnification, such as Figure 2As shown, and a third mode operating at a second magnification different from the first magnification, as shown Figure 3 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, such as Figure 1 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. The first magnification may be about 1.5 magnifications or greater, for example, about 1.5 magnifications to about 5 magnifications, the second magnification may be about 6 magnifications to about 11 magnifications, and the third magnification may be about 4 magnifications to about 6 magnifications between the first and second magnifications. 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.

[0072] The driving member can move (M1, M2) each of the second and third lens groups G2 and G3, or operate them in an initial mode according to an operating mode selected from the first mode to the third mode. In detail, each of the multiple driving members is connected to the second lens group G2 and 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 can be, 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 positioned 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 positioned at a position defined as a second position (position 2) 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 positioned at a third position (position 3) closer to the sensor than the first position. The first position can be an area between the second position and the third position.

[0073] The first position where the second lens group G2 is positioned in the first mode may be an area between the second position and the third position where the second lens group G2 is positioned in the second mode and the third mode. The first position where the third lens group G3 is positioned in the first mode may be an area between the second position and the third position where the third lens group G3 is positioned in the second mode and the third mode.

[0074] Depending on the operating mode, at least one of the second lens group G2 and the third lens group G3 can be moved along the optical axis OA (M1, M2), and the first lens group G1 can be set at a fixed position. Depending on the operating mode, the second lens group G2 can be moved along the optical axis OA (M1), and the first lens group G1 can be set at a fixed position. Depending on the operating mode, the third lens group G3 can be moved along the optical axis OA (M2), and the first lens group G1 can be arranged at a fixed position. For example, the optical axis distance DG12 between the sensor-side surface of the third lens 103 and the object-side surface of the fourth lens 104 can vary depending on the operating mode. The optical axis distance DG23 between the sensor-side surface of the fifth lens 105 and the object-side surface of the sixth lens 106 can vary depending on the operating mode.

[0075] In each of the first, second, and third positions according to the operating mode, the first to third lens groups G1, G2, and G3 can have a set gap with adjacent lens groups. Thus, the optical system 1000 can have a constant total track 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. Furthermore, the optical axis distance DG4 between the third lens group G3 and the optical filter 500 can be variable according to the operating mode.

[0076] The effective length CA1 of the first lens 101 is the largest among the lenses, and the effective diameter CA6 of the sixth lens 106 is the smallest among the lenses. The effective length CA1 of the first lens 101 can be 5 mm or greater. The effective length CA6 of the sixth lens 106 can be less than 5 mm, for example, 3.8 mm or greater. In terms of absolute values ​​of focal length, the focal length F6 of the first lens 106 can be the largest among the lenses. The difference (absolute value) in focal length between two adjacent lenses can be the largest between the fifth lens 105 and the sixth lens 106, and the smallest between the third lens 103 and the fourth lens 104. An aperture stop is provided around the object-side surface of the fourth lens 104, and the focal length of the fourth lens 104 can be the smallest among the lenses. That is, the lens with the largest absolute value of focal length can be provided within the third lens group G3, and the lens with the smallest absolute value of focal length can be provided within the second lens group G2.

[0077] The center thickness CT1 of the first lens 101 can be the thickest within the first lens group G1. The absolute values ​​of the radii of curvature of the first to fourth surfaces S1, S2, S3, and S4 of the first and second lenses 101, 102 are set to 5 mm or greater so as not to significantly change the angle of refraction of incident light, which is then directed to the fourth lens 104 of the second lens group G2 via the third lens 103. The sum of the center thicknesses CT3 and CT4 of the third and fourth lenses 103, 104 can be greater than the sum of the center thicknesses CT1, CT2, and CT3 of the first, second, and third lenses 101, 102, and 103. The sum of the center thicknesses CT3 and CT4 of the third and fourth lenses 103, 104 can be greater than the sum of the center thicknesses CT6 and CT7 of the sixth and seventh lenses 106, 107. Therefore, the second lens group G2 can guide light incident through the first lens group G1 to the effective area of ​​the third lens group G3. The sum of center thicknesses CT6 and CT7 of the sixth lens 106 and the seventh lens 107 may be greater than the sum of center thicknesses of the first to third lenses 101, 102, and 103. Therefore, the third lens group G3 may provide a small change across an optical path.

[0078] Depending on the magnification of 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 at least 0.2 mm and at most 8 mm. Specifically, the optical axis distance DG12 between the first lens group G1 and the second lens group G2 can be moved by 0.2 mm or more, for example, within a range of 0.2 mm to 8 mm, and the optical axis distance DG23 between the second lens group G2 and the third lens group G3 can be moved by 1 mm or more, for example, within a range of 1 mm to 4 mm. In addition, the center distance DG4 between the seventh lens 107 and the filter 500 can be moved by 1 mm or more, for example, within a range of 1 mm to 10 mm. The relationship between DG12, DG23, and DG4 in the first, second, and third modes is as follows.

[0079] First mode: DG4 <DG23<DG12

[0080] Second mode: DG12 <DG23<DG4

[0081] The third mode: DG12 <DG23<DG4

[0082] The F number of the optical system 1000 provides brightness of 2.0 or more according to an operation mode, and the F number may be in the range of 2.2 to 3.8. An aperture stop may be located between the first lens group G1 and the second lens group G2.

[0083] The optical system 1000 according to the embodiment can satisfy at least one, two, or more of the mathematical formulas described below. Therefore, the optical system 1000 according to the embodiment can effectively correct aberrations that vary depending on the operating mode. Furthermore, the optical system 1000 according to the embodiment can effectively provide an autofocus (AF) function for an object at various magnifications and can have a slim and compact structure.

[0084] Hereinafter, the optical axis distances between two adjacent lenses may be defined as CG1 to CG7, from the distance between the first and second lenses to the distance between the seventh and eighth lenses. The effective lengths from the object-side and sensor-side surfaces of the first lens 101 to the object-side and sensor-side surfaces of the seventh lens 107 may be defined as CA11, CA12, CA71, and CA72. The units for thickness, distance, and effective diameter values ​​are in mm. Additionally, when the shape of the lens surface includes a circular or non-circular shape and the lens has a partially circular shape, the effective length may be defined as the major axis effective length or the maximum diameter.

[0085] [Mathematical formula 1]nL_G1>nL_G3 (nL is an integer greater than or equal to 2)

[0086] In Math 1, nL_G2 means the number of lenses included in the second lens group G2. Here, nL_G1>nL_G2, nL_G1>nL_G3 may be satisfied.

[0087] [Mathematical formula 2] 0.7 <CA41 / CA11<1.5

[0088] In Mathematical Formula 2, CA41 is the effective length of the seventh surface S7 of the fourth lens 104, and CA11 is the effective length of the first surface S1 of the first lens 101 or the effective length in the long axis direction. When Mathematical Formula 2 is satisfied, a high EPD (entrance pupil diameter) can be provided compared to the optical system. Preferably, 0.7 <CA41 / CA11<1。

[0089] [Mathematical formula 3]1 <CT1 / CT3<4

[0090] If Mathematical Formula 3 satisfies the center thickness of the first lens 101 and the third lens 103, the aberration characteristics of the optical system 1000 can be improved. Preferably, 2 <CT1 / CT3<3.5。

[0091] [Math 4]0 <CT1 / CT4<1

[0092] If the center thicknesses of the first lens 101 and the fourth lens 104 satisfy the mathematical formula 4, the optical system 1000 can improve the aberration characteristics. Preferably, 0.3 < CT1 / CT4 < 0.85 can be satisfied. The center thickness CT4 of the fourth lens 104 is the thickest among the lenses and has a convex shape on both surfaces, so that the fourth lens 104 can improve the light incident efficiency of the first lens group G1 and can refract light into the effective area of the sixth lens 106 having the minimum effective length.

[0093] [Mathematical formula 4-1] 2 < CT4 / CT3 < 5

[0094] When the center thicknesses of the third lens 103 and the fourth lens 104 in the mathematical formula 4-1 are satisfied, the optical system 1000 can improve the aberration characteristics. In addition, by setting the thick center thickness CT4 of the fourth lens 104 that is convex on both surfaces, the fourth lens 104 can refract the incident light into the entire area of the fifth lens 105. Preferably, 3 < CT4 / CT3 < 4 can be satisfied.

[0095] [Mathematical formula 5] 1 < ET3 / CT3 < 4

[0096] In the mathematical formula 4, ET3 means the thickness (mm) in the direction of the optical axis OA at the edge, and this edge is the end of the effective area of the third lens 103. When the optical system 1000 according to the embodiment satisfies the mathematical formula 5, the optical system 1000 can improve the distortion characteristics of the light passing through the first lens group G1. Preferably, 1.5 < ET3 / CT3 < 2.6 can be satisfied.

[0097] [Mathematical formula 5-1] 2 < CT4 / ET4 < 3.5

[0098] In the mathematical formula 5-1, the center thickness CT4 of the fourth lens 104 is set to be more than twice the edge thickness ET4, thereby improving the aberration of the optical system 1000. Preferably, 2.2 < CT4 / ET4 < 3 can be satisfied.

[0099] Here, if the center thickness of the i-th lens is set to CTi and the edge thickness of the i-th lens is set to ETi, the ratio of CTi / ETi can be the largest when i is 4 and the smallest when i is 3. That is, the lens with the largest difference between the center thickness and the edge thickness can be set as the object-side lens of the second lens group G2, and the lens with the smallest difference between the center thickness and the edge thickness can be set as the sensor-side lens of the first lens group G1. In addition, the average value of the center thicknesses CT4, CT5, and CT6 of the fourth to sixth lenses 104, 105, and 106 can satisfy the following conditions.

[0100] Condition: 2.5 mm < Aver(CT4:CT6) < 3.5 mm

[0101] In this way, the center thicknesses CT4, CT5, and CT6 of the fourth to sixth lenses 104, 105, and 106 located in the middle of the optical system 1000 are set to be relatively thick, so that the refraction angle of light by the lens adjacent to the last lens 107 can be set not to be large.

[0102] [Equation 6] FG1 < 0

[0103] In Equation 6, FG1 is the effective focal length (EFL) of the first lens group G1 and can have a value less than 0. FG1 is the combined focal length of the first to third lenses. When Equation 6 is satisfied, the optical aberration of the optical system, that is, the optical aberration of the first lens group G1, can be improved. The effective focal length of the second lens group G2 is FG2, the effective focal length of the third lens is FG3, and the following equations can be satisfied.

[0104] [Equation 6-1]: FG2 * 2 < │FG1│

[0105] [Equation 6-2]: FG2 * 2 < │FG1│ < FG2 * 3 (* is multiplication)

[0106] [Equation 6-3]: │FG1│ < │FG3│

[0107] In this way, by adjusting the focal lengths of each lens group, the refraction angle of light passing through the lens can be adjusted. Here, when the effective focal lengths of the optical system 1000 according to the first to third modes are FMd1, FMd2, and FMd3, the following equations can be satisfied.

[0108] [Equation 6-4]: FMd3 < │FG3│

[0109] [Equation6-5]: FMd1 < │FG1│

[0110] [Equation 6-6]: FG2 * 2 < FMd2

[0111] [Equation 7] CRA < 20

[0112] In Mathematical Formula 7, CRA (Chief ray angle) is the chief ray incident angle, and in the optical system, the incident angle of the chief ray can be less than 20 degrees at most according to the first mode, the second mode, and the third mode, and can be, for example, less than 15 degrees. The first mode can be a wide-angle mode, the second mode can be a mid-focus mode, and the third mode can be a telephoto mode. Here, in the case of the first mode (wide-angle mode), at a field of 1.0, the chief ray incident angle can be greater than the chief ray incident angle in the case of the second mode. In the case of the above-mentioned third mode (telephoto mode), the chief ray incident angle in a field of 1.0 can be 11 degrees or less, and the chief ray incident angle of the second mode can be less than the chief ray incident angle of the first mode. If Mathematical Formula 6 is satisfied, the peripheral light ratio can be ensured.

[0113] [Math 8](TTL / DG1)>3.5

[0114] 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 refers to the distance (mm) between the center of the first surface S1 of the first lens 101 and the center of the sixth surface S6 of the third lens 103 along the optical axis OA. TTL refers to the distance (mm) from the object-side first surface S1 of the first lens 101 to the imaging surface of the image sensor 300 along 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 good peripheral light ratio.

[0115] The following mathematical formulas may also be included.

[0116] [Mathematical formula 8-1] (TTL / DG2) < (TTL / DG1)

[0117] [Mathematical formula 8-2]DG3 <DG2

[0118] Here, DG2 is the optical axis distance of the second lens group G2, and is the distance from the center of the object-side surface of the fourth lens 104 to the center of the sensor-side surface of the fifth lens 105. DG3 is the optical axis distance of the third lens group G3, and is the distance from the center of the object-side surface of the sixth lens 106 to the center of the sensor-side surface of the seventh lens 107.

[0119] [Mathematical formula 9]2 <TTL / EPD3<7

[0120] In Mathematical Expression 9, EPD3 refers to the size of the entrance pupil diameter (EPD) of the optical system 1000 when operating in the third mode (i.e., the telephoto mode). When the optical system 1000 according to an embodiment satisfies Mathematical Expression 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 the telephoto mode. Preferably, 4 < TTL / EPD3 < 5 can be satisfied.

[0121] [Mathematical Expression 9-1] 4 < TTL / EPD1 < 8

[0122] [Mathematical Expression 9-2] 3 < TTL / EPD2 < 6

[0123] [Mathematical Expression 9-3] (TTL / EPD3) < (TTL / EPD2) < (TTL / EPD1)

[0124] In Mathematical Expressions 9-1 to 9-3, EPD1 is the size of the entrance pupil diameter of the optical system in the first mode (wide-angle mode), and EPD2 is the size of the entrance pupil diameter of the optical system in the second mode (mid-tele mode). When the optical system satisfies the above conditions, it can ensure a bright image according to each mode.

[0125] [Mathematical Expression 10] 3 < CT_Max / CT_Min < 67

[0126] In Mathematical Expression 10, CT_Max is the thickest thickness among the center thicknesses of the lenses, CT_Min is the thinnest thickness among the center thicknesses of the lenses, and when Mathematical Expression 10 is satisfied, the aberration characteristics of the optical system can be improved. Preferably, 4 < CT_Max / CT_Min < 6 can be satisfied.

[0127] [Mathematical Expression 11] 1 < CA_Max / CA_Min < 3

[0128] In Mathematical Expression 11, CA_Max is the maximum effective length in the lens surface, CA_Min is the minimum effective diameter in the lens surface, and when Mathematical Expression 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. Preferably, 1 < CA_Max / CA_Min < 1.5 can be satisfied. Therefore, the difference in the effective length between the lens surfaces of different lenses can be set to be at most less than 1.5 times.

[0129] [Mathematical Expression 12] 0.1 < ΣCG_Wide / TTL < 0.6

[0130] In Mathematical Formula 12, ΣCG is the sum of the center distances between adjacent lenses, and ΣCG_Wide is the sum of the center distances between adjacent lenses in the first mode. When the optical system satisfies Mathematical Formula 12, the center distance DG12 between the first lens group and the second lens group, and the center distance between the second lens group and the third lens group can be set according to the wide-angle mode. The center distance DG12 between the first lens group and the second lens group can be the center distance CG3 between the third lens 103 and the fourth lens 104, and varies depending on the operating mode. The center distance DG23 between the second lens group and the third lens group can be the center distance CG5 between the fifth lens 105 and the sixth lens 106, and varies depending on the operating mode. Preferably, 0.3<ΣCG_Wide / TTL<0.5 can be satisfied.

[0131] [Mathematical formula 12-1] 0.1 < ΣCG_Mid / TTL < 0.4

[0132] [Mathematical formula 12-2] 0 < ΣCG_Tele / TTL < 0.3

[0133] In Mathematical Formulas 12-1 and 12-2, ΣCG_Mid is the sum of the center distances between adjacent lenses in the second mode, and ΣCG_Tele is the sum of the center distances between adjacent lenses in the third mode. When the optical system satisfies Mathematical Formulas 12-1 and 12-2, the center distance DG12 between the first lens group and the second lens group and 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. Preferably, the condition of ΣCG_Tele<ΣCG_Mid<ΣCG_Wide can be satisfied. When the optical system 1000 according to the embodiment satisfies at least one or two or more of Mathematical Formulas 1 to 12, the optical system 1000 can have a slim structure. In addition, the optical system 1000 can have improved assembly characteristics and a mechanically stable shape.

[0134] [Math 13] 0.5 <DG1 / DG2<2

[0135] In Math 13, DG1 is the optical axis distance of the first lens group G1, and DG2 is the optical axis distance of the second lens group G2. In Math 13, the optical axis distances of the first lens group G1 and the second lens group G2 can be set to adjust TTL. Preferably, 0.5 <DG1 / DG2<1。

[0136] [Mathematical formula 13-1] 0.5 <DG1 / DG3<1.5

[0137] In Mathematical Expression 13-1, DG3 is the optical axis distance of the third lens group G3. Preferably, 0.8 < DG1 / DG3 < 1 can be satisfied. That is, DG1 < DG3 can be satisfied.

[0138] [Mathematical Expression 14] 0.5 < DG2 / DG3 < 2

[0139] In Mathematical Expression 14, DG2 is the optical axis distance of the second lens group G2, and DG3 is the optical axis distance of the third lens group G3. Preferably, 0.9 < DG2 / DG3 < 1.3 can be satisfied. When the optical system 1000 according to the embodiment satisfies at least one of Mathematical Expressions 13 and 14, it has a relatively small TTL and can provide various magnifications according to at least three mode changes.

[0140] [Mathematical Expression 15] 0 < CG2 / TTL < 0.2

[0141] In Mathematical Expression 15, CG2 is the optical axis distance between the second lens 102 and the third lens 103. When the optical system 1000 satisfies Mathematical Expression 15, the optical system 1000 has a relatively small TTL and can have improved optical characteristics by controlling the stray light incident on the first lens group G1. Preferably, 0 < CG2 / TTL < 0.1 can be satisfied.

[0142] [Mathematical Expression 16] 2 < TTL / (DG2 + DG3) < 5

[0143] Mathematical Expression 16 sets the sum of TTL and the optical axis distances of the second lens group G2 and the third lens group G3, and when the optical system 1000 satisfies Mathematical Expression 16, the optical system 1000 has a relatively small TTL and can improve the chromatic aberration characteristics. Preferably, 2.2 < TTL / (DG2 + DG3) < 3 can be satisfied.

[0144] [Mathematical Expression 17] 20 < Vd4 - Vd5 < 70

[0145] In Mathematical Expression 17, Vd4 represents the Abbe number of the fourth lens 104, and Vd5 represents the Abbe number of the fifth lens 105. When the absolute value of the difference in Abbe numbers between the fourth lens and the fifth lens of the optical system 1000 according to the embodiment satisfies Mathematical Expression 17, the optical system 1000 can improve the chromatic aberration characteristics. Preferably, Vd5 < Vd4 can be satisfied, and �0 < Vd4 can be satisfied.

[0146] [Mathematical Expression 18] 15 < |Vd7 – Vd6| < 60

[0147] In Mathematical Expression 18, Vd7 means the Abbe number of the seventh lens, and Vd6 means the Abbe number of the sixth lens. When the absolute value of the difference in Abbe numbers between the sixth lens and the seventh lens satisfies Mathematical Expression 18, the optical system 1000 can improve the chromatic aberration characteristics. Preferably, Vd6 < Vd7 can be satisfied, and 40 < Vd7 can be satisfied.

[0148] [Mathematical Expression 19] 1.6 < Nd2

[0149] In Mathematical Expression 19, Nd2 means the refractive index of the second lens 102 at the d line. When the optical system 1000 according to the embodiment satisfies Mathematical Expression 19, the incident light can be dispersed, and the effective area of the lens arranged behind the second lens 102 can be ensured. Preferably, 1.65 < Nd2 can be satisfied.

[0150] [Mathematical Expression 19-1] 1.60 < Nd5

[0151] [Mathematical Expression 19-2] 1.65 < Nd6

[0152] The refractive indices of the fourth lens 104 and the seventh lens 107 can be less than 1.6. Among the lenses, the number of lenses with a refractive index exceeding 1.60 can be more than the number of lenses with a refractive index less than 1.60.

[0153] [Mathematical Expression 20] 2 < L1R1 / L3R2 < 5

[0154] In Mathematical Expression 20, L1R1 means the radius of curvature of the first surface S1 on the object side of the first lens 101, and L3R2 means the radius of curvature of the sixth surface S6 on the sensor side of the third lens 103. When the optical system 1000 according to the embodiment satisfies Mathematical Expression 20, the optical system 1000 can control the stray light incident on the first lens group G1. Preferably, 3 < L1R1 / L3R2 < 4 can be satisfied. Since the third lens 103 has a concave surface on the sensor side on the optical axis, an increase in the effective diameter of the fourth lens 104 can be suppressed.

[0155] [Mathematical Expression 21] 1.5 < L1R1 / L4R1 < 3.5

[0156] In Mathematical Expression 21, L1R1 means the radius of curvature of the first surface S1 on the object side of the first lens 101, and L4R1 means the radius of curvature of the seventh surface S7 on the object side of the fourth lens 104. When the optical system 1000 according to the embodiment satisfies Mathematical Expression 21, the optical system 1000 can have good optical performance at various magnifications. Preferably, 2.3 < L1R1 / L4R1 < 3 can be satisfied.

[0157] [Mathematical Expression 22] 0 < L3R2 / L4R1 < 2

[0158] In Mathematical Expression 22, L3R2 means the radius of curvature of the sixth surface S6 on the sensor side of the third lens 103, and L4R1 means the radius of curvature of the seventh surface S7 on the object side of the fourth lens 104. When the optical system 1000 according to the embodiment satisfies Mathematical Expression 22, when operating at various magnifications in at least three modes, the optical system 1000 can have good optical performance at the periphery of the field of view (FOV). Preferably, 0.5 < L3R2 / L4R1 < 1.5 can be satisfied. The fourth lens 104 is the first lens of the second lens group G2, has a biconvex shape on the optical axis, and can have a positive optical power. Therefore, the gap between the convex sensor-side surface of the fourth lens 104 and the concave object-side surface of the fifth lens 105 can be tightly closed.

[0159] [Mathematical Expression 23] 2 < L1R1 / L7R2 < 5

[0160] In Mathematical Expression 23, L7R2 means the radius of curvature of the fourteenth surface S14 on the sensor side of the seventh lens 107. When the optical system 1000 satisfies Mathematical Expression 23, the optical system 1000 can have good optical performance at the center and periphery of the FOV. Preferably, 3 < L1R1 / L8R2 < 4 can be satisfied. Here, when the radius of curvature of the object-side surface of the i-th lens is R1i and the radius of curvature of the sensor-side surface is R2i, the absolute value of R1i / R2i can be the largest when i = 3 and the smallest when i = 5. For example, when i = 3, the absolute value of R13 / R23 is 5 or more, and when i = 5, the absolute value of R15 / R25 is 0.5 or less. In addition, the lenses for which the absolute value of R1i / R2i is less than 1.1 can be i = 1, 4, 5, 6.

[0161] [Mathematical Expression 24] 0 < Md12_mG2 / TTL < 0.5

[0162] In Mathematical Expression 24, Md12_mG2 means 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, Md12_mG2 represents the movement distance of the second lens group G2 in the first mode and the second mode, and means 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 Mathematical Expression 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 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. Preferably, 0 < Md12_mG2 / TTL < 0.2 can be satisfied.

[0163] [Mathematical Expression 25] 0 < Md23_mG2 / TTL < 0.5

[0164] In Mathematical Expression 25, Md23_mG2 represents the difference in the center distance (unit: mm) 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, Md23_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 G, can be greater than the maximum movement distance of the third lens group G3. When the optical system 1000 according to the embodiment satisfies Mathematical Expression 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 thin structure. In addition, when controlling the position of the second lens group G2, the movement distance can be minimized, so that improved power consumption characteristics can be achieved. 0 < Md23_mG2 / TTL < 0.1 can be satisfied. In addition, the condition Md23_mG2 < Md12_mG2 can be satisfied.

[0165] [Mathematical Expression 26] 0.3 < Md12_mG2 / DG2 < 1

[0166] Mathematical formula 26 can set the moving distance of the second lens group G2 and the optical axis distance of the second lens group G2. When the optical system 1000 satisfies mathematical formula 26, the moving distance of the second lens group G2 can be minimized when the magnification changes, so that the optical system 1000 can have a slim structure. In addition, when the position of the second lens group G2 is controlled, the moving distance can be minimized, so that it can have improved power consumption characteristics. Preferably, 0.3 can be satisfied. <Md12_mG2 / DG2<0.8。

[0167] [Mathematical formula 27]0 <Md23_mG3 / DG3<0.5

[0168] In Mathematical Formula 27, Md23_mG3 means the center distance difference after the movement of the third lens group G3 when changing from the second mode to the first mode or from the first mode to the second mode. When the optical system 1000 satisfies Mathematical Formula 27, the moving distance of the third lens group G3 can be minimized when the magnification changes, so that the optical system 1000 can have a slim structure. In addition, when the position of the third lens group G3 is controlled, the moving distance can be minimized, so that it can have improved power consumption characteristics. Preferably, 0.1 can be satisfied. <Md23_mG3 / DG3<0.4。

[0169] [Mathematical formula 28] 1<(CT1 / ET1) / (CT3 / ET3)<5

[0170] In Equation 28, CT1 / ET1 is the value obtained by dividing the optical axis thickness of the first lens 101 by the end thickness, and CT3 / ET3 is the value obtained by dividing the optical axis thickness of the third lens 103 by the end thickness. If the values ​​obtained by dividing the center thickness and the end thickness of the first lens 101 and the third lens 103 satisfy Equation 28 at the above ratios, chromatic aberration can be improved and incident light can be controlled. Preferably, 1<(CT1 / ET1) / (CT3 / ET3)<3 can be satisfied.

[0171] [Mathematical formula 29] 0 < (CT1 / ET1) / (CT7 / ET7) < 2

[0172] In Equation 29, CT1 / ET1 is the value obtained by dividing the thickness of the seventh lens 107 at the optical axis by the thickness at the end. If the value obtained by dividing the center thickness and the end thickness of the first lens 101 and the seventh lens 107 satisfies Equation 29, chromatic aberration can be improved and incident light can be controlled. Preferably, 0.5<(CT1 / ET1) / (CT7 / ET7)<1.5 can be satisfied.

[0173] [Mathematical formula 29-1]2<(CT4 / ET4) / (CT5 / ET5)<3.5

[0174] In Math 29-1, CT4 / ET4 is a value obtained by dividing the optical axis thickness of the fourth lens 104 by the end thickness. If the value obtained by dividing the center thickness and the end thickness of the fourth lens 104 and the fifth lens 105 satisfies Math 29-1, chromatic aberration can be improved in the second lens group G2 and incident light can be controlled.

[0175] [Mathematical formula 30]1 <Md1(DG12 / DG23)<5

[0176] In Mathematical Formula 30, Md1(DG12 / DG23) means 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. When the optical system 1000 according to the embodiment satisfies Mathematical Formula 30, the optical system 1000 can have improved optical characteristics at the first magnification. In detail, the optical system 1000 can have improved aberration characteristics at the first magnification, and can improve optical performance at the center and periphery of the FOV. Preferably, 1 can be satisfied. <Md1(DG12 / DG23)<2。

[0177] [Mathematical formula 31]0 <Md3(DG12 / DG23)<0.7

[0178] In Mathematical Formula 31, Md3(DG12 / DG23) means 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 the embodiment satisfies Mathematical Formula 31, the optical system 1000 can have improved optical characteristics at the second magnification. In detail, the optical system 1000 can have improved aberration characteristics at the second magnification and improve the optical performance at the peripheral portion of the FOV. Preferably, 0 can be satisfied. <Md3(DG12 / DG23)<0.5。

[0179] [Math 32] 0.5 <TD2 / TTL<1

[0180] In Mathematical Expression 32, TD2 is the optical axis distance from the center of the object-side surface of the first lens in the second mode to the center of the sensor-side surface of the seventh lens. When the optical system 1000 according to the embodiment satisfies Mathematical Expression 32, the optical system 1000 can have improved optical characteristics in the medium focal mode, which is the second mode. Specifically, the optical system 1000 has improved aberration characteristics in the medium focal mode and can improve the optical performance in the peripheral portion of the FOV. Preferably, 0.65 < TD2 / TTL < 0.9 can be satisfied.

[0181] [Mathematical Expression 33] 1 < TD1 / TD2 < 1.5

[0182] In Mathematical Expression 33, TD1 is the optical axis distance from the center of the object-side surface of the first lens in the first mode to the center of the sensor-side surface of the seventh lens. When the optical system 1000 according to the embodiment satisfies Mathematical Expression 33, the optical system 1000 can have improved optical characteristics in the first mode and the second mode and can reduce the influence on TTL. Specifically, the optical system 1000 has improved aberration characteristics in the first mode and the second mode and can improve the optical performance in the peripheral portion of the FOV. Preferably, 1 < TD1 / TD2 < 1.4 can be satisfied.

[0183] [Mathematical Expression 33-1] 0.5 < TD1 / TTL < 1

[0184] Preferably, 0.7 < TD1 / TTL < 0.95 can be satisfied. The relationship between the maximum optical axis distance TD1 and TTL according to each mode can be set.

[0185] [Mathematical Expression 33-2] 1 < TD1 / TD3 < 1.5

[0186] In Mathematical Expression 33-2, TD3 is the optical axis distance from the center of the object-side surface of the first lens in the third mode to the center of the sensor-side surface of the seventh lens. The optical system 1000 can have improved optical characteristics in the first mode and the third mode and can reduce the influence on TTL.

[0187] [Mathematical Expression 34] 13 mm < TD3 < TD2 < TD1 < 25 mm

[0188] Equation 34 compares the optical axis distances of the lenses in the first, second, and third modes, where 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).

[0189] [Math 35] 0.1 <BFL2 / TTL<1

[0190] In Mathematical Formula 35, BFL2 (back focal length 2) 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 second mode. When the optical system 1000 according to the embodiment satisfies Mathematical Formula 35, the optical system 1000 can adjust the focus position to the imaging surface of the image sensor 300 in the second mode. In detail, 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, 0.2 <BFL2 / TTL<0.4。

[0191] [Mathematical formula 36]2 <BFL3 / BFL1<4

[0192] In Math 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 the embodiment satisfies Math 36, the optical system 1000 can adjust the focus position toward the imaging surface of the image sensor 300 in the first mode and the third mode. In detail, the optical system 1000 has improved optical characteristics in the first mode and the third mode, and can improve the optical performance of the peripheral portion of the FOV. Preferably, 2.2 can be satisfied. <BFL3 / BFL1<3。

[0193] [Mathematical formula 37]2 <TD3 / BFL3<5

[0194] Mathematical formula 37 is a value for comparing 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 107 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 the embodiment satisfies Mathematical formula 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 improve optical performance in the peripheral portion of the FOV. Preferably, 2.5 can be satisfied. <TD3 / BFL3<4。

[0195] [Mathematical formula 38]2 <Md_CG_Max / Md_CG_Min<8

[0196] In Math 38, Md_CG_Max means the maximum center distance among the center distances between the first lens to the seventh lens in the first, second, and third modes, and Md_CG_Min means 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 Math 38, the TTL and optical axis distance of the lens can be adjusted according to each mode. Preferably, 4 can be satisfied. <Md_CG_Max / Md_CG_Min<7。

[0197] [Math 39] 1mm <BFL1<6mm

[0198] Mathematical formula 39 means the optical axis distance between the seventh lens and the image sensor in the first mode. When the optical system satisfies mathematical formula 39, the focus position of the image surface toward the image sensor in the first mode can be adjusted. Preferably, it can include 2mm <BFL1<3.5mm。

[0199] [Mathematical formula 40] 20 <Aver_Vd<45

[0200] In Math 40, Aver_Vd is the average value of the Abbe numbers of the first to seventh lenses. When the optical system satisfies Math 40, the optical system 1000 can have improved aberration characteristics and resolution. Preferably, 25 <Aver_Vd<40。 [Math 41] 1.5 <Aver_Nd<1.8

[0201] In Math 40, Aver_Nd is the average value of the refractive indices of the first to seventh lenses. When the optical system satisfies Math 41, the optical system 1000 can have improved aberration characteristics and resolution. Preferably, 1.58 can be satisfied. <Aver_Nd<1.63。

[0202] [Mathematical formula 41-1] 10 < ∑Vd / ∑Nd < 40

[0203] In Mathematical formula 41-1, ∑Vd means the sum of the Abbe numbers of each of the plurality of lenses. ∑Nd means the sum of the refractive indices of each of the plurality of lenses. When the optical system 1000 according to the embodiment satisfies Mathematical formula 41-1, the optical system 1000 can have improved aberration characteristics and resolution. Preferably, Mathematical formula 41-1 can satisfy 17 < ∑Vd / ∑Nd < 25. Preferably, the following condition can be satisfied: (∑Vd - ∑Nd) < 225.

[0204] [Mathematical formula 42] 1.5 < │FG1 / FG2│ < 4

[0205] In Mathematical formula 42, FG1 means the effective focal length (EFL) of the first lens group G1, and FG2 means the effective focal length of the second lens group G2. FG2 is the combined focal length of the fourth and fifth lenses. When Mathematical formula 42 is satisfied, the size of the optical system, such as TTL, can be reduced. Preferably, FG2 > 0 is satisfied. FG3 is the combined focal length of the sixth and seventh lenses, and FG3 < 0, and the following condition can be satisfied: │FG3│ > │FG1│ > FG2. Preferably, 1.8 < │FG1 / FG2│ < 3 can be satisfied.

[0206] [Mathematical formula 43] 1 < FMd2 / FMd1 < 10

[0207] In Mathematical formula 43, FMd^1 is the effective focal length of the optical system in the first mode, and FMd2 is the effective focal length of the optical system in the second mode. Preferably, 1 < FMd2 / FMd1 < 3 can be satisfied. When the optical system satisfies Mathematical formula 43, the effective focal length can be adjusted according to the first mode and the second mode.

[0208] [Mathematical formula 43-1] 1 < FMd3 / FMd2 < 10

[0209] In Mathematical formula 43, FMd3 is the effective focal length of the optical system in the third mode. Preferably, 1 < FMd3 / FMd2 < 2 can be satisfied, and the following condition can be satisfied: (FMd3 / FMd1) > (FMd3 / FMd2). When the optical system satisfies Mathematical formula 43-1, the effective focal length can be adjusted according to the second mode and the third mode.

[0210] In the first mode, the effective focal length (Fmd1) of the optical system and the focal length of each lens can satisfy the following conditions.

[0211] Condition 1: 5 < F1 / Fmd1 < 13

[0212] Condition 2: 1 < F2 / Fmd1 < 4

[0213] Condition 3: 0<│F3 / Fmd1│<1

[0214] Condition 4: 0 <F4 / Fmd1<1

[0215] Condition 5: 1<│F5 / Fmd1│<4

[0216] Condition 6: 5 <F6 / Fmd1<30

[0217] Condition 7: 1.5<│F7 / Fmd1│<5

[0218] In the second mode, the effective focal length (Fmd2) of the optical system and the focal length of each lens may satisfy the following conditions.

[0219] Condition 1: 0 <F1 / Fmd2<1

[0220] Condition 2: 0.5 <F2 / Fmd2<2

[0221] Condition 3: 1<│F3 / Fmd2│<4

[0222] Condition 4: 2 <F4 / Fmd2<5

[0223] Condition 5: 0.3 <│F5 / Fmd2│<1.5

[0224] Condition 6:0 <F6 / Fmd2<0.5

[0225] Condition 7: 0.2 <│F7 / Fmd2│<1.5

[0226] In the third mode, the effective focal length (Fmd3) of the optical system and the focal length of each lens may satisfy the following conditions.

[0227] Condition 1: 0 <F1 / Fmd3<0.6

[0228] Condition 2: 0.3 <F2 / Fmd3<2

[0229] Condition 3: 1<│F3 / Fmd3│<5

[0230] Condition 4: 1.2 <F4 / Fmd3<6

[0231] Condition 5: 0.3 <│F5 / Fmd3│<2

[0232] Condition 6:0 <F6 / Fmd3<0.5

[0233] Condition 7: 0.2 < │ F7 / Fmd3 │ < 2

[0234] [Mathematical formula 44]2 <FMd2 / EPD2<7

[0235] In Math 44, FMd2 is the effective focal length of the optical system in the second mode (middle focus), and EPD2 means the size of the EPD of the optical system 1000 in the second mode. When the optical system 1000 according to the embodiment satisfies Math 44, the optical system 1000 can ensure a bright image when operating in the second mode. Preferably, 2 can be satisfied. <FMd2 / EPD2<4。

[0236] [Math 45] 0.1 <FMd1 / EPD1<3

[0237] In Math 34, FMd1 is the effective focal length of the optical system in the first mode (wide angle), and EPD1 means the size of the EPD of the optical system 1000 when the first mode is operated. When the optical system 1000 according to the embodiment satisfies Math 45, the optical system 1000 can ensure a bright image when operating in the first mode. Preferably, 1 can be satisfied. <FMd1 / EPD1<3。

[0238] [Math 46]FMd1 <FMd2<FMd3

[0239] In Mathematical Formula 46, FMd1, FMd2, and FMd3 mean the effective focal lengths of the optical system in the first, second, and third modes. 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. Preferably, 55 mm may be satisfied. <FMd1<FMd2<FMd3<25mm。

[0240] [Mathematical formula 47]0 <TTL / FMd2<2

[0241] Mathematical formula 47 can adjust TTL by comparing the effective focal length in TTL and the second mode. Preferably, 1 can be satisfied. <TTL / FMd2<2。

[0242] [Math 48] 0.1 <TTL / FMd1<5

[0243] Mathematical formula 47 can adjust TTL by comparing TTL with the effective focal length in the first mode. Preferably, 1 can be satisfied. <TTL / FMd1<3。

[0244] [Mathematical formula 49]1 <CA_Max / ImgH<3

[0245] In Mathematical Expression 49, CA_Max means the maximum effective length (CA) of the lens surfaces of the lenses included in the optical system 1000. ImgH is the distance from the 0 field-of-view region of the image sensor 300 centered on the image surface overlapping the optical axis OA to the 1.0 field-of-view region of the image sensor 300. ImgH means 1 / 2 of the maximum diagonal length of the effective area of the image sensor 300. When the optical system 1000 according to the embodiment satisfies Mathematical Expression 49, the optical system 1000 can be provided in a thin and compact manner. In addition, the optical system 1000 can achieve high resolution and high image quality. The above range of ImgH is 2 mm or more, for example, 2 mm to 3 mm.

[0246] Here, the effective lengths CA1 to CA7 of the first lens to the seventh lens 101 - 107 can satisfy the following conditions.

[0247] Condition 1: 0.5 < CA1 / (Imgh * 2) < 1.5

[0248] Preferably, CA1 > (Imgh * 2) can be satisfied.

[0249] Condition 2: 0.4 < CA2 / (Imgh * 2) < 1.4

[0250] Preferably, CA2 > (Imgh * 2) can be satisfied.

[0251] And, the following conditions can be satisfied: CA3 < (Imgh * 2), CA5 < (Imgh * 2), CA6 < (Imgh * 2), CA7 < (Imgh * 2). In addition, the following conditions can be satisfied: CA4 > (Imgh * 2). When the effective length of the object-side surface of the first lens 101 is CA11 and the effective length of the sensor-side surface is CA12, the following conditions can be satisfied.

[0252] Condition 1: 1 < CA11 / (Imgh * 2) < 1.5

[0253] Condition 2: 0.8 < CA12 / (Imgh * 2) < 1.2

[0254] [Mathematical Expression 50] 5 < TTL / ImgH < 12

[0255] When the optical system 1000 satisfies Mathematical Expression 39, the optical system 1000 can have a smaller TTL, so that the optical system 1000 can be provided in a thin and compact manner. Preferably, it can be in the range of 6 < TTL / ImgH < 10.

[0256] [Mathematical Expression 51] 1 < BFL2 / ImgH < 3

[0257] If the optical system 1000 according to the embodiment satisfies Equation 51, the BFL required for a small image sensor of less than 1 inch can be ensured. In addition, if the optical system 1000 satisfies Equation 51, the optical system 1000 can operate at various magnifications while maintaining the TTL, and can have excellent optical characteristics in the central part and the peripheral part of the FOV. Preferably, it can be in the range of 2 < BFL2 / ImgH < 3.2.

[0258] [Equation 52] 2 < BFL3 / ImgH < 4

[0259] If the optical system 1000 according to the embodiment satisfies Equation 52, the BFL required for a small image sensor of less than 1 inch can be ensured. When the optical system 1000 satisfies Equation 52, the optical system 1000 can operate at various magnifications while maintaining the TTL, and can have excellent optical characteristics in the central part and the peripheral part of the FOV. Preferably, 2.5 < BFL3 / ImgH < 3.5 can be satisfied.

[0260] [Equation 53] 1 < EPD1 < EPD2 < EPD3 < 7

[0261] In Equation 53, EPD1, EPD2, and EPD3 refer to the sizes of the entrance pupil diameters of the optical systems according to the first to third modes, and the brightness can be adjusted according to each mode.

[0262] [Equation 54] 0 < Max_Distortion < 3

[0263] In Equation 54, distortion means the maximum value or peak of the distortion from the center (0.0F) to the diagonal end (1.0F) of the image sensor based on the optical characteristics detected by the image sensor 300. When the optical system 1000 satisfies Equation 54, the optical system 1000 can improve the distortion characteristics and set the conditions for image processing. Preferably, Max_Distortion < 1.5 can be satisfied.

[0264] [Equation 55] 8° < FOV3 < FOV2 < FOV1 < 45°

[0265] In Equation 55, FOV1, FOV2, and FOV3 refer to the diagonal fields of view of the optical system in the first, second, and third modes. FOV refers to the field of view (degrees) in the diagonal direction of the optical system 1000, and an optical system of less than 45 degrees can be provided.

[0266] In addition, the following conditions may be satisfied according to the relationship between the field of view angle (FOV1, FOV2, FOV3) of each mode and the optical axis distance (BFL1, BFL2, BLF3) between the last lens and the image sensor 300.

[0267] Condition 1: 5 <FOV1 / BFL1<15

[0268] Condition 2: 2 <FOV2 / BFL2<5

[0269] Condition 3: 1 <FOV3 / BFL3<3

[0270] The optical system can set the relationship between the 1 / 2 angle of the field of view and the CRA, as in Condition 4 below.

[0271] Condition 4: 0.5 <HFOV / CRA<1.5

[0272] [Mathematical formula 56]

[0273]

[0274] In Mathematical Formula 56, Z may refer to the sagittal height, which is the distance from any position on the aspherical surface to the vertex of the aspherical surface in the direction of the optical axis. In addition, Y may refer to the distance from any position on the aspherical surface to the optical axis in a direction perpendicular to the optical axis. In addition, c may refer to the curvature of the lens, and K may refer to the conic constant. In addition, A, B, C, D, E, and F may refer to aspherical coefficients.

[0275] The optical system 1000 according to the embodiment can satisfy at least one of the above-mentioned mathematical formulas 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 mathematical formulas 1 to 55, it is possible to effectively correct the degradation of optical characteristics such as chromatic aberration, vignetting, diffraction effects, and degradation of image quality in the peripheral area caused by the movement of the lens group. In addition, the optical system 1000 according to the embodiment can significantly reduce the moving distance of the lens group and provide an autofocus (AF) function for various magnifications with excellent power consumption characteristics.

[0276] Since the optical system 1000 according to the embodiment satisfies at least one or two or more of the above-mentioned mathematical formulas 1 to 55, it can have improved assembly performance and a mechanically stable form, and is provided with a slim structure, so that the optical system 1000 and the camera module including the optical system can have a compact structure.

[0277] Hereinafter, the optical system 1000 according to the 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, the first lens to the third lens 101, 102, and 103, and the second lens group G2 can include two lenses, for example, the fourth lens 104 and the fifth lens 105. In addition, the third lens group G3 can include two lenses, for example, the sixth lens 106 and the seventh lens 107. In the optical system 1000 according to the embodiment, the object-side surface (seventh surface S7) of the fourth lens 104 can be used as an aperture stop, and the above-mentioned filter 500 can be arranged between the fourth lens group G4 and the image sensor 300.

[0278] Figure 5 The curvature radius on the optical axis OA of the first to seventh lenses 101 to 107, the center thickness (CT) of the lens, the center distance (CG) between adjacent lenses, the refractive index at the d line, the Abbe number, and the effective length (CA) are shown. Figure 5 , DG4 is the optical axis distance between the seventh lens and the filter 500 and may vary according to the movement of the third lens group G3.

[0279] [Table 1]

[0280] Referring to Table 1, a ratio CT / ET of a center thickness CT to an edge thickness ET of each of the plurality of lenses may be different from each other, a CT / ET value of the fourth lens 104 may be the largest, and a CT / ET value of the third lens may be the smallest.

[0281] like Figure 1 and Figure 2 As shown, the Abbe number Vd4 of the fourth lens 104 included in the second lens group G2 can be higher than the Abbe number Vd5 of the fifth lens 105 by 20 or more. Since the fourth lens 104 and the fifth lens 105 have the above-mentioned Abbe number difference, the chromatic aberration change 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 by 20 or more or 30 or more than the Abbe number Vd6 of the sixth lens 106. Since the sixth lens 106 and the seventh lens 107 have the above-mentioned Abbe number difference, chromatic aberration change occurring when magnification changes according to the movement (M2) of the third lens group G3 can be minimized and / or compensated to perform an achromatic function.

[0282] The camera module according to the embodiment can obtain information about an object at various magnifications. In detail, the driving member can control the positions of the second lens group G2 and the third lens group G3, and thus, the camera module can operate at various magnifications. For example, referring to Figure 1 、 Figure 8 and Figure 11 , 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 to approximately 5 times. In detail, 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 to third lens groups G3 can be arranged at a set interval. For example, the second lens group G2 can be positioned in an area spaced apart from the first lens group G1 by a first distance DG12, and the third lens group G3 can be positioned in an area spaced apart from the second lens group G2 by a second distance DG23. Here, the first to second distances DG12 and DG23 can refer to the intervals between the lens groups on the optical axis OA and can vary depending on the operating mode.

[0283] When the camera module operates in the first mode, the optical system 1000 may have a TTL value and a BFL1 value at the first position. In addition, the optical system 1000 may have an FMD1 defined as a first effective focal length (EFL) at the first position. In addition, the FOV of the camera module in the first mode may be less than approximately 35 degrees, and the aperture value (F-number) may be less than approximately 3. 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. In addition, the optical system 1000 may have an FMD2 defined as a second effective focal length (EFL) at the second position. In addition, the FOV of the camera module in the second mode may be less than approximately 25 degrees, and the aperture value 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. In addition, the optical system 1000 may have an FMD3 defined as a third effective focal length (EFL) at the third position. In addition, the FOV of the camera module in the third mode may be less than about 20 degrees, and the aperture value may be less than about 4.

[0284] like Figure 6 As shown, 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 (1.0 field) at the height (field height) of the image sensor is 50% or more. The optical system 1000 can have the following in the first mode: Figure 8 and Figure 11 The excellent aberration characteristics shown. Figure 8 is a diffraction MTF characteristic diagram for the optical system 1000 operating in the first mode (first magnification), and Figure 11 This graph shows aberration characteristics. The diffraction MTF characteristic graph is measured in units of approximately 0.252mm, and the spatial frequency range is 0.000mm to 2.2520mm. In the diffraction MTF graph, T represents the MTF variation per millimeter of spatial frequency for the tangential image, and R represents the MTF variation per millimeter of spatial frequency for the sagittal image. Here, the MTF (Modulation Transfer Function) depends on the spatial frequency per millimeter period.

[0285] exist Figure 11 In the aberration diagram, from left to right are the diagrams for measuring spherical aberration (longitudinal spherical aberration), astigmatism field curve and distortion. Figure 8 In FIG, the X-axis may represent focal length (mm) and distortion (%), and the Y-axis may mean the height of the image. In addition, the graphs regarding spherical aberration are graphs regarding light of wavelength bands of about 435 nm, about 486 nm, about 546 nm, about 587 nm, and about 656 nm, and the graphs regarding astigmatism and distortion aberration are graphs regarding light of a wavelength band of 546 nm. Figure 11 In the aberration diagram, it can be interpreted that the closer each curve is to the Y-axis, the better the aberration correction function. Figure 11 , it can be seen that the optical system 1000 according to the embodiment has a measurement value close to the Y axis in almost all areas. Table 2 and Figure 3 The items of the above mathematical formula in the optical system 1000 of the embodiment include TTL (mm), BFL, effective focal length (F) (mm), ImgH (mm), effective length (CA) (mm), thickness (mm), TTL (mm), optical axis distance TD from the first surface S1 to the fourteenth surface S14 (mm), the focal length F1, F2, F3, F4, F5, F6 and F7 of each of the first to seventh lenses (mm), the sum of the refractive index of each lens, the sum of the Abbe number of each lens, the sum of the center thickness 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 length of the first lens group and the second lens group, the aperture value, etc.

[0286] [Table 2]

[0287] Table 3 shows the center distance between the first lens group and the second lens group, the center distance between the second lens group and the third lens group, the center distance between the seventh lens and the filter DG4 according to the first mode to the third mode, the effective focal length (EFL) according to each mode, the entrance pupil size (EPD) according to each mode, the optical axis distance (TD) of the lenses according to each mode, the aperture value and the angle of view, and the BFL according to each mode.

[0288] [Table 3]

[0289] Tables 4 and 5 show the results of the above-mentioned equations 1 to 55 for the optical system 1000 of the embodiment. Referring to Table 5, it can be seen that the optical system 1000 satisfies at least one, two or more, or three or more of the equations 1 to 55. Specifically, it can be seen that the optical system 1000 according to the embodiment satisfies all of the equations 1 to 55. Therefore, the optical system 1000 can achieve good optical performance and excellent optical characteristics in both the central and peripheral portions of the FOV.

[0290] [Table 4]

[0291] [Table 5]

[0292] The optical system and the camera module according to the embodiment may satisfy at least one or two of Math Formulas 1 to 30 and / or Math Formulas 31 to 55, or may satisfy all of Math Formulas.

[0293] Figure 14 is a diagram showing a camera module according to an embodiment applied to a mobile terminal. Figure 14 , 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 include an image capture function. In addition, the camera module 10 may include at least one of an autofocus function, a zoom function, and an OIS function.

[0294] The camera module 10 can process still images or video frames obtained by the image sensor 300 in a shooting mode or a video call mode. The processed image frames 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 drawings, the camera module can also be arranged on the front 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 slim structure and can capture objects at various magnifications.

[0295] 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 can be used primarily in situations where the autofocus function of the image using the camera module 10 deteriorates, for example, at a close distance of 10 meters or less or in a dark environment. The autofocus device 31 may include a light-emitting unit including a vertical cavity surface emitting laser (VCSEL) semiconductor element and a light-receiving unit such as a photodiode that converts light energy into electrical energy. The mobile terminal 1 may also include a flash module 33. The flash module 33 may include a light-emitting element that emits light internally. The flash module 33 may emit light in the visible light wavelength band. For example, the flash module 33 may emit white light or light of a color similar to white. However, embodiments are not limited thereto, and the flash module 33 may emit light of various colors. The flash module 33 may be operated by the mobile terminal's camera operation or 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.

[0296] 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 only 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 combinations and modifications should be interpreted as being included in the scope of the present invention. In addition, although the embodiments have been described above, they are only examples and do not limit the present invention, and a person skilled in the art of the present invention has illustrated the above within the scope of the essential features of the present embodiment. It can be seen that various modifications and applications that have not yet been made are possible. For example, each component specifically shown in the embodiment 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 to third lens groups are arranged along the optical axis from the object toward the sensor side, each lens group includes at least one lens, wherein the first lens group and the third lens group have positive optical power, wherein the second lens group has negative optical power, Wherein, the position of the first lens group is fixed, wherein each of the second lens group and the third lens group moves along the optical axis according to an operation mode, wherein the first lens closest to the object in the first lens group has positive optical power, The optical axis distance of the second lens group is greater than the optical axis distance of the first lens group and the third lens group. wherein the number of lenses in the third lens group is smaller than the number of lenses in the first lens group, and The third lens group includes a lens having a meniscus shape convex toward the sensor side and a lens having a meniscus shape convex toward the object side.

2. The optical system according to claim 1, wherein The lenses of the first to third lens groups are made of plastic, and Among the lenses of the first lens group to the third lens group, the number of lenses with negative optical power is less than the number of lenses with positive optical power.

3. The optical system according to claim 1, wherein: The optical axis distances from the first lens group to the third lens group are DG1, DG2 and DG3, Among them, the following mathematical formula is satisfied: 0.5 <DG1 / DG2<1 0.8 <DG1 / DG3<1。 4. The optical system according to any one of claims 1 to 3, wherein: A lens having a largest absolute value of focal length among the first to third lens groups is disposed in the third lens group.

5. The optical system according to any one of claims 1 to 3, wherein: The optical axis distance of the third lens group is DG3, The optical axis distance between the surface of the lens closest to the object side among the lenses of the first lens group and the imaging surface of the image sensor is TTL, Among them, the following mathematical formula is satisfied: 2 <TTL / (DG2+DG3)<5。 6. The optical system according to any one of claims 1 to 3, wherein: 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 operation modes of the optical system include a wide-angle mode, a mid-focus mode, and a telephoto mode.

7. The optical system according to claim 6, wherein: an optical axis distance between an object-side surface of a lens closest to the object in the first lens group and a sensor-side surface of a lens closest to the image sensor in the third lens group varies according to the operation mode, 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 at least 0.2 mm or greater and at most 8 mm or less.

8. The optical system according to claim 6, wherein: The wide angle mode is Md1, Wherein, in the wide-angle mode, the optical axis distance between the first lens group and the second lens group is DG12, The optical axis distance between the second lens group and the third lens group is DG23. Among them, the following mathematical formula is satisfied: 1 <Md1(DG12 / DG23)<5。 9. The optical system according to claim 6, wherein: The telephoto mode is Md3, 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 mathematical formula is satisfied: <Md3(DG12 / DG23)<0.7。 10. The optical system according to any one of claims 1 to 3, wherein: The maximum distance between adjacent lenses in the operating mode is Md_CG_Max, Wherein, the minimum distance between adjacent lenses in the operation mode is Md_CG_Min, Among them, the following mathematical formula is satisfied: 2 <Md_CG_Max / Md_CG_Min<8。 11. The optical system according to any one of claims 1 to 3, wherein: The number of lenses in the first lens group is greater than the number of lenses in the second lens group, The absolute value of the focal length of the first lens group is greater than twice the focal length of the second lens group.

12. The optical system according to claim 6, wherein: The effective focal length of the optical system in the wide-angle mode is FMd1, Wherein, the focal length of the first lens is F1, Among them, the following mathematical formula is satisfied: 5 <F1 / Fmd1<13。 13. The optical system according to claim 6, wherein: The effective focal length of the optical system in the telephoto mode is FMd3, Among them, the following mathematical formula is satisfied: <F1 / Fmd3<0.6。 14. The optical system according to claim 6, wherein: The field of view in the wide-angle mode is FOV1, the field of view in the medium-focus mode is FOV2, and the field of view in the telephoto mode is FOV3, and the following mathematical formula is satisfied: 8° <FOV3<FOV2<FOV1<45°。 15. An optical system comprising: A first lens group including first to third lenses; a second lens group including a fourth lens and a fifth lens; as well as The third lens group includes a sixth lens and a seventh lens, The first lens group, the second lens group and the third lens group are arranged along the optical axis from the object toward the sensor. wherein the first lens has positive refractive power and has a convex object-side surface on the optical axis, The third lens has negative refractive power and is biconcave on the optical axis. wherein the fifth lens and the sixth lens have refractive powers of opposite signs and have a meniscus shape convex toward the sensor, Wherein, the second lens group and the third lens group move in the optical axis direction, wherein the optical axis distance between the seventh lens and the image sensor varies according to the operation mode, Among them, the number of lenses having a refractive index greater than 1.60 among the first lens to the seventh lens is greater than the number of lenses having a refractive index less than 1.

60. Wherein, the refractive index of the second lens is Nd2, Among them, the following mathematical formula is satisfied: 1.65 <Nd2。 16. The optical system according to claim 15, wherein: The first lens group and the third lens group have negative refractive power, Wherein, the second lens and the fourth lens have positive refractive power.

17. The optical system according to claim 15 or 16, wherein: The fourth lens and the seventh lens have a refractive index less than 1.

6.

18. The optical system according to claim 15 or 16, wherein: A lens surface having the largest absolute value of the radius of curvature of the object-side surface and the sensor-side surface of each of the first to seventh lenses is the object-side surface of the third lens.

19. The optical system according to claim 15 or 16, wherein: The effective length of the first lens is the largest among the lenses, wherein the maximum length of the first lens in a first direction orthogonal to the optical axis is different from the maximum length in a second direction orthogonal to the optical axis, The effective length of the largest lens surface from the first lens to the seventh lens is CA_Max, Wherein, 1 / 2 of the diagonal length of the image sensor is ImgH, Among them, the following mathematical formula is satisfied: 1 <CA_Max / ImgH<3。 20. A camera module, comprising: Image sensor; Optical system; as well as a driving member that moves at least one of the plurality of lens groups of the optical system in the optical axis direction, wherein the optical system comprises the optical system according to claim 1 or 15, wherein the driving member moves a position of each of the second lens group and the third lens group of the optical system in the optical axis direction.

Images