Optical system and camera module including the same

Abstract

The disclosed optical system according to an embodiment of the present invention may include first to seventh lenses arranged along an optical axis from an object side to a sensor side, wherein: the first lens has a convex object-side surface; at least one of an object-side surface and a sensor-side surface of the sixth lens has a critical point; each of an object-side surface and a sensor-side surface of the seventh lens has a critical point; at least one of an object-side surface and a sensor-side surface of the seventh lens has a free-form surface shape in which a lens surface perpendicular to the optical axis in the first direction and a lens surface perpendicular to the optical axis in the second direction are asymmetric to each other; opposite lens surfaces of the free-form surface in a first direction of the reference optical axis have shapes symmetrical to each other, and opposite lens surfaces of the free-form surface in a second direction of the reference optical axis have shapes symmetrical to each other.

Description

Technical Field

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

[0002] Camera modules capture objects and store them as images or videos, and are installed in various applications. In particular, camera modules are manufactured in very small sizes and are applied not only to portable devices such as smartphones, tablets, and notebook computers, but also to drones and vehicles to provide various functions.

[0003] 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 may perform an auto focus (AF) function of aligning the focal length of the lens by automatically adjusting the distance between the image sensor and the imaging lens, and may perform a zoom function of zooming in or out by increasing or decreasing the magnification of a remote object through a zoom lens. In addition, the camera module employs an image stabilization (IS) technology to correct or prevent image instability caused by an unstable fixture or camera movement caused by a user's action.

[0004] The most important element of a camera module for obtaining an image is an imaging lens that forms an image. Recently, interest in high performance such as high image quality and high resolution has been increasing, and research on an optical system including a plurality of lenses is being conducted to achieve such high performance. For example, research is being conducted to achieve a high performance optical system using a plurality of imaging lenses having positive (+) and / or negative (-) refractive power.

[0005] However, when multiple lenses are included, there is a problem in that it is difficult to obtain excellent optical characteristics and aberration characteristics. In addition, when multiple lenses are included, the thickness, spacing, size, etc. of the multiple lenses may cause the total length, height, etc. to increase, thereby increasing the total size of the module including the multiple lenses.

[0006] In addition, in order to achieve high resolution and high definition, the size of image sensors is increasing. However, when the size of image sensors increases, the TTL (Total Track Length) of an optical system including multiple lenses also increases, resulting in an increase in the thickness of a camera and a mobile terminal including the optical system.

[0007] Therefore, a new optical system that can solve the above problems is needed. Summary of the invention

[0008]

Technical issues

[0009] Embodiments of the present invention provide an optical system with improved optical characteristics.

[0010] The embodiment provides an optical system having excellent optical performance in both the central and peripheral portions of a field of view.

[0011] The embodiment provides an optical system capable of having a slim structure.

[0012]

Technical solution

[0013] An optical system according to an embodiment of the present invention includes a first lens to a seventh lens, which are arranged along the optical axis from the object side to the sensor side, wherein the object side surface of the first lens is convex, at least one of the object side surface and the sensor side surface of the sixth lens has at least one critical point, each of the object side surface and the sensor side surface of the seventh lens has a critical point, and at least one of the object side surface and the sensor side surface of the seventh lens has a freeform surface shape, in which a lens surface orthogonal to the optical axis in a first direction and a lens surface orthogonal to the optical axis in a second direction are asymmetric, and the freeform surface can have symmetrical lens surfaces on both sides of the first direction relative to the optical axis, and have symmetrical lens surfaces on both sides of the second direction relative to the optical axis.

[0014] According to an embodiment of the present invention, each of the object-side surface and the sensor-side surface of the sixth lens has a critical point, and the critical point of the object-side surface of the seventh lens is the critical point of the object-side surface and the sensor-side surface of the sixth lens, which can be positioned closer to the optical axis.

[0015] According to an embodiment of the present invention, each of the object-side surface and the sensor-side surface of the seventh lens has a critical point, and the critical point of the object-side surface of the seventh lens can be positioned closer to the optical axis than the critical point of the object-side surface and the sensor-side surface of the sixth lens.

[0016] According to an embodiment of the present invention, the sixth lens may include regions having different thicknesses at the same radial position in a first direction and a second direction orthogonal to the optical axis.

[0017] According to an embodiment of the present invention, the seventh lens may include regions having different thicknesses within the same radius in different axial directions between the first direction and the second direction relative to the optical axis.

[0018] According to an embodiment of the present invention, the sixth lens may include regions having different thicknesses within the same radius in different axial directions between a first direction and a second direction orthogonal to the optical axis.

[0019] According to an embodiment of the present invention, the seventh lens may include regions having different thicknesses within the same radius in different axial directions between a first direction and a second direction orthogonal to the optical axis.

[0020] According to an embodiment of the present invention, a maximum angle between a normal line perpendicular to a tangent line passing through a sensor-side surface of the sixth lens and the optical axis may have different angles in a first direction and a second direction orthogonal to the optical axis.

[0021] According to an embodiment of the present invention, a maximum angle between a normal line perpendicular to a tangent line passing through a sensor-side surface of the seventh lens and the optical axis may have different angles in a first direction and a second direction orthogonal to the optical axis.

[0022] According to an embodiment of the present invention, the first lens has positive refractive power and has a meniscus shape convex toward the object side on the optical axis, and the second lens and the third lens may have refractive powers opposite to each other and each of the second lens and the third lens may have a meniscus shape convex toward the object side on the optical axis.

[0023] According to an embodiment of the present invention, the fourth lens has positive refractive power, the fifth lens has negative refractive power, and the sum of center thicknesses of the fourth lens and the fifth lens may be smaller than a center distance between the second lens and the third lens.

[0024] According to an embodiment of the present invention, the sixth lens has positive refractive power, the object-side surface of the sixth lens has a convex shape on the optical axis, and the sensor-side surface of the sixth lens has a concave shape on the optical axis, and the seventh lens has negative refractive power, the object-side surface of the seventh lens may have a convex shape on the optical axis, and the sensor-side surface of the seventh lens may have a concave shape on the optical axis.

[0025] An optical system according to an embodiment of the present invention includes first to seventh lenses, which are arranged along the optical axis from the object side to the sensor side, wherein the first lens has a convex object side surface, at least one of the object side surface and the sensor side surface of the sixth lens has a free-form surface, each of the object side surface and the sensor side surface of the seventh lens has a critical point, and at least one of the object side surface and the sensor side surface of the seventh lens has a free-form surface shape, in which the lens surface orthogonal to the optical axis in the first direction is asymmetric with the lens surface orthogonal to the optical axis in the second direction, and satisfies the mathematical formula: 0≤|EFLX-EFLY|≤0.1, wherein EFLX can be the effective focal length in the first direction, and EFLY can be the effective focal length in the second direction.

[0026] According to an embodiment of the present invention, the sensor-side surface of the sixth lens is a free-form surface having a critical point and satisfies the mathematical formula: 50 < Inf62 * L6S2_Max_slope < 120, where Inf62 is the average distance from the optical axis to the critical point of the sensor-side surface of the sixth lens in the first direction and the second direction, and L6S2_Max_slope may be the maximum angle between the optical axis and the normal line perpendicular to the tangent line passing through any point on the sensor-side surface of the sixth lens.

[0027] According to an embodiment of the present invention, the sensor-side surface of the seventh lens is a free-form surface having a critical point and satisfies the following mathematical formula: 30 < Inf72 * L7S2_Max_slope < 110, where Inf72 is the average distance from the optical axis to the critical point of the sensor-side surface of the seventh lens in the first direction and the second direction, and L7S2_Max_slope may be the maximum angle between the optical axis and the normal line perpendicular to the tangent line passing through any point on the sensor-side surface of the seventh lens.

[0028] According to an embodiment of the present invention, EFLX and EFLY may have different values.

[0029] According to an embodiment of the present invention, the sensor-side surface of the seventh lens has a free-form surface, and the distance from the optical axis to the critical point in the first direction of the sensor-side surface of the seventh lens and the distance from the optical axis to the critical point in the second direction may be different.

[0030] According to an embodiment of the present invention, the center distance between the sixth lens and the seventh lens is the maximum value among the center distances from the first lens to the seventh lens, and the center thickness of the second lens may be the maximum value among the center thicknesses of the first lens to the seventh lens.

[0031] According to an embodiment of the present invention, the average distance from the optical axis to the critical points in the first direction and the second direction of the object-side surface of the seventh lens is Inf71, the average distance from the optical axis to the critical points in the first direction and the second direction of the sensor-side surface of the seventh lens is Inf72, and the following mathematical formula is satisfied:

[0032] 0.2 < Inf71 / Inf72 < 1

[0033] Inf71 and Inf72 are different from each other,

[0034] Satisfy the following mathematical formula: 0.4 < TTL / (Imgh * 2) < 0.7

[0035] (The total lens length (TTL) is the distance on the optical axis from the vertex of the object-side surface of the first lens to the image surface of the image sensor, and ImgH is 1 / 2 of the maximum diagonal length of the image sensor).

[0036] An optical system according to an embodiment of the present invention includes: a first lens group on the object side, having three or fewer lenses; and a second lens group on the sensor side of the first lens group, having four or fewer lenses, wherein the first lens group has a positive (+) refractive power on the optical axis, the second lens group has a negative (-) refractive power on the optical axis, the number of lenses in the second lens group is less than twice the number of lenses in the first lens group, the lens surface of the first lens group and the second lens group that is closest to the second lens group has the smallest effective diameter, the last lens of the first lens group and the second lens group that is closest to the image sensor has the largest effective diameter, the sensor-side surface of the first lens group that is closest to the second lens group has a concave shape, the object-side surface of the second lens group that is closest to the first lens group has a concave shape, the sensor-side surface of the last lens of the first lens group and the second lens group that is closest to the image sensor has a freeform surface with a critical point, the sensor-side surface that is closest to the image sensor has a lens surface orthogonal to the optical axis in a first direction and a lens surface orthogonal to the optical axis in a second direction, and has an asymmetric freeform surface, and the freeform surface may have symmetric lens surfaces on both sides of the first direction with respect to the optical axis, and may have symmetric lens surfaces on both sides of the second direction.

[0037] According to an embodiment of the present invention, the focal length of the second lens group in the first direction and the focal length of the second lens group in the second direction may be different from each other.

[0038] According to an embodiment of the present invention, the optical system satisfies the following mathematical formula:

[0039] 0.4 < TTL / (Imgh*2) < 0.7 (TTL is the distance on the optical axis from the vertex of the object-side surface of the first lens to the image surface of the image sensor, and ImgH is 1 / 2 of the maximum diagonal length of the image sensor).

[0040] According to an embodiment of the present invention, the first lens group includes a first lens to a third lens arranged along the optical axis in the direction from the object side to the sensor side, the second lens group includes a fourth lens to a seventh lens arranged along the optical axis in the direction from the object side to the sensor side, each of the object-side surface and the sensor-side surface of the sixth lens is a freeform surface with a critical point, and the object-side surface of the seventh lens may have a freeform surface with a critical point.

[0041] A camera module according to an embodiment of the present invention includes: an image sensor; and a filter between the image sensor and the last lens of the optical system, wherein the optical system includes the optical system disclosed above and satisfies the following mathematical formula:

[0042] 0.5 < F / TTL < 1.2

[0043] 0<(F / TTL) / nL<0.3

[0044] (F is the average value of the total focal length in two directions orthogonal to the optical axis of the optical system, TTL (Total track length) is the distance from the vertex of the object side surface of the first lens to the top surface of the sensor on the optical axis, and nL is the total number of lenses).

[0045]

Beneficial Effects

[0046] The optical system and the camera module according to the embodiment may have improved optical characteristics. In detail, the optical system may have improved aberration characteristics and resolution according to the surface shape, refractive power, thickness of the plurality of lenses, and distances between adjacent lenses among the plurality of lenses.

[0047] The optical system and the camera module according to the embodiments may have improved distortion and aberration characteristics and may have good optical performance in the center and peripheral portions of the FOV.

[0048] The optical system according to the embodiment may have improved optical characteristics and a smaller total length to lens (TTL), so that the optical system and a camera module including the same may be provided in a slim and compact structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 is a configuration diagram of an optical system and a camera module according to an embodiment of the present invention.

[0050] Figure 2 It is shown Figure 1 An explanatory diagram of the relationship between the image sensor, the nth lens and the n-1th lens of the optical system in the first direction Y.

[0051] Figure 3 It is shown Figure 1 An explanatory diagram of the relationship in the second direction X between the image sensor, the nth lens and the n-1th lens of the optical system.

[0052] Figure 4 is from Figure 1 Plane view of the optical system as seen by the n-1th lens.

[0053] Figure 5 It is shown that according to Figure 1 A table of lens data of the first embodiment of the optical system.

[0054] Figure 6 and Figure 7 ⊥ ...1 is an example of the aspherical coefficient of the lens according to the first embodiment of the present invention.

[0055] Figure 8 : is a table showing the center thicknesses of the first to fifth lenses and the distances between adjacent lenses based on the direction perpendicular to the optical axis in the optical system according to the first embodiment of the present invention.

[0056] Fig. 9 : is a table showing the center thicknesses of the sixth lens and the seventh lens and the center distances between adjacent lenses based on a direction orthogonal to the optical axis in the optical system according to the first embodiment of the present invention.

[0057] Fig.10 : is a table showing Sag (sagittal) height data of the nth lens and the (n-1)th lens in the optical system according to the first embodiment of the present invention.

[0058] Fig.11 It is shown that according to Figure 1 A table of lens data of a second embodiment of the optical system.

[0059] Fig.12 and Fig.13 ⊥ ...1 is an example of the aspherical coefficient of the lens according to the first embodiment of the present invention.

[0060] Fig.14 : is a table showing the center thicknesses of the first to fifth lenses and the distances between adjacent lenses based on the direction perpendicular to the optical axis in the optical system according to the first embodiment of the present invention.

[0061] Fig.15 : is a table showing the center thicknesses of the sixth lens and the seventh lens and the center distances between adjacent lenses based on the height direction orthogonal to the optical axis in the optical system according to the first embodiment of the present invention.

[0062] Fig.16 : is a table showing Sag (sagittal) height data of the nth lens and the (n-1)th lens in the optical system according to the first embodiment of the present invention.

[0063] Fig.17 : is a comparative view of thickness according to height and position (0 degree, 30 degrees, 45 degrees, 60 degrees, 90 degrees) of the seventh lens of the optical system according to the first embodiment and the second embodiment of the present invention.

[0064] Fig.18 is a graph showing Sag height data according to height and position (0 degree, 30 degree, 45 degree, 60 degree, 90 degree) of the sensor-side surface of the seventh lens of the optical system according to the first and second embodiments of the present invention.

[0065] Fig.19is a diagram showing that a camera module according to an embodiment is applied to a mobile terminal. DETAILED DESCRIPTION

[0066] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The technical concept of the present invention is not limited to some embodiments to be described, but can be implemented in various other forms, and one or more components can be selectively combined or replaced to be used within the scope of the technical concept of the present invention. In addition, unless specifically defined and clearly described, the terms (including technical terms and scientific terms) used in the embodiments of the present invention can be interpreted according to the meanings commonly understood by ordinary technicians in the field to which the present invention belongs, and the meanings of commonly used terms (such as terms defined in dictionaries) can be interpreted in the context of considering the contextual meaning of the relevant technology.

[0067] In addition, 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 specifically described with a sentence, the singular form may also include the plural form, and when stated as at least one (or one or more) of A, B and C, 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 the first, second, A, B, (a) and (b) may be used. These terms are only used to distinguish the component from other components, and these terms may not be determined by the nature, sequence, process, etc. of the corresponding constituent elements. Moreover, when describing that a component is "connected", "coupled" or "combined" to another component, the description may include not only directly connecting, coupling or combining to other components, but also "connecting", "coupling" or "combining" by other components between the component and the other component. In addition, in the case of being described as being formed or arranged on "above (up)" or "below (below)" of each component, the description includes not only the situation that two components are in direct contact with each other, but also the situation that one or more other components are formed or arranged between the two components. In addition, when expressed as “above” or “below”, it can refer to a downward direction as well as an upward direction with respect to one element.

[0068] In the description of the present invention, "object side surface" may refer to the surface of the lens facing the object side relative to the optical axis OA, and "sensor side surface" may refer to the surface of the lens facing the imaging surface (image sensor) relative to the optical axis. The convex surface of the lens may mean that the lens surface on the optical axis has a convex shape, and the concave surface of the lens may mean that the lens surface on the optical axis has a concave shape. The radius of curvature, the center thickness, and the distance between the lenses described in the lens data table may mean the value on the optical axis, and the unit is millimeter. 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 or edge of the effective area of ​​the lens through which the incident light passes. Depending on the measurement method, the size of the effective diameter of the lens surface may have a measurement error of up to ±0.4mm. The paraxial area refers to a very narrow area near the optical axis, and is an area where the distance of the light from the optical axis OA is almost zero. In the following, the concave shape or convex shape of the lens surface is described as the optical axis, and the paraxial area may also be included.

[0069] Figure 1 1 and 2 are diagrams showing an optical system 1000 and a camera module having the optical system 1000 according to first and second embodiments of the present invention.

[0070] refer to Figure 1 , the optical system 1000 may include a plurality of lens groups G1 and G2. In detail, each of the plurality of lens groups G1 and G2 includes at least one lens. For example, the optical system 1000 may include a first lens group G1 and a second lens group G2 sequentially arranged along the optical axis OA from the object side toward the image sensor 300. The number of lenses of the second lens group G2 in the plurality of lens groups G1 and G2 may be greater than the number of lenses of the first lens group G1, for example, greater than 1 times the number of lenses of the first lens group G1 and less than t times the number of lenses of the first lens group G1.

[0071] The first lens group G1 may include at least one lens. The first lens group G1 may include three or fewer lenses. For example, the first lens group G1 may include three lenses. The second lens group G2 may include at least two or more lenses. The second lens group G2 may have more lenses than the first lens group G1, and may include 6 or fewer lenses, or 5 or fewer lenses. The number of lenses of the second lens group G2 may have a difference of 1 or more and 2 or less compared to the number of lenses of the first lens group G1. For example, the second lens group G2 may include four lenses.

[0072] The first lens group G1 refracts light incident through the object side to converge, and the second lens group G2 converts the light emitted through the first lens group G1 to diffuse around the image sensor 300 .

[0073] In the optical system 1000, the total length of the lens (TTL) can be less than 70% of the diagonal length of the image sensor 300, for example, it can be in the range of 40% to 60% or 40% to 55%. TTL is the distance from the object side surface of the first lens closest to the object side to the image surface of the image sensor along the optical axis OA, and the diagonal length of the image sensor 300 can be the maximum diagonal length of the image sensor 300, and can be twice the distance Imgh from the optical axis OA to the end of the diagonal. Therefore, a slim optical system and a camera module having the optical system can be provided. The total number of lenses of the first lens group G1 and the second lens group G2 is 6 to 8.

[0074] The first lens group G1 and the second lens group G2 may have a set interval on the optical axis OA. The optical axis distance between the first lens group G1 and the second lens group G2 on the optical axis OA is a separation distance on the optical axis OA, and may be an optical axis distance between a sensor-side surface of a lens closest to the sensor side among the lenses of the first lens group G1 and an object-side surface of a lens closest to the object side among the lenses of the second lens group G2. The optical axis distance between the first lens group G1 and the second lens group G2 is greater than the maximum center thickness of the lenses of the first lens group G1, and may be greater than the maximum center thickness of the lenses of the second lens group G2.

[0075] The optical axis distance between the first lens group G1 and the second lens group G2 is smaller than the optical axis distance of the first lens group G1, and may be 41% or more of the optical axis distance of the first lens group G1, for example, in the range of 41% to 61% or 46% to 56% of the optical axis distance of the first lens group G1. Here, the optical axis distance of the first lens group G1 is the optical axis distance between the object-side surface of the lens closest to the object side in the first lens group G1 and the sensor-side surface of the lens closest to the sensor side.

[0076] The optical axis distance between the first lens group G1 and the second lens group G2 may be 30% or less of the optical axis distance of the second lens group G2, for example, in the range of 10% to 30%. The optical axis distance of the second lens group G2 is the optical axis distance between the object-side surface of the lens closest to the object side and the sensor-side surface of the lens closest to the sensor side in the second lens group G2.

[0077] The lens with the smallest average effective diameter in the first lens group G1 may be the lens closest to the second lens group G2. The lens with the smallest average effective diameter in the second lens group G2 may be the lens closest to the first lens group G1. The lens with the smallest effective diameter in the optical system 1000 may be the last lens of the first lens group G1. The lens with the smallest effective diameter in the optical system 1000 may be any lens adjacent to the optical axis distance between the first lens group G1 and the second lens group G2. Here, the average effective diameter is the average of the object side effective diameter and the sensor side effective diameter of the lens. Therefore, the optical system 1000 can have good optical performance not only in the central part of the FOV (field of view) but also in the peripheral part, and can improve chromatic aberration and distortion aberration. The size of the lens with the smallest effective diameter in the first lens group G1 may be smaller than the size of the lens with the smallest effective diameter in the second lens group G2.

[0078] Optical system 1000 may include eight lenses or fewer, or seven lenses or fewer.

[0079] The lens closest to the object side among the lenses of the first lens group G1 has a positive (+) refractive power, and the lens closest to the sensor side among the lenses of the second lens group G2 may have a negative (-) refractive power. In the optical system 1000, the number of lenses having a positive (+) refractive power may be greater than the number of lenses having a negative (-) refractive power. In the first lens group G1, the number of lenses having a positive (+) refractive power may be greater than the number of lenses having a negative (-) refractive power. In the second lens group G2, the number of lenses having a positive (+) refractive power and the number of lenses having a negative (-) refractive power may be the same.

[0080] Each of the plurality of lenses 100 may include an effective area and an ineffective area. The effective area is an area through which light incident on each lens 100 passes, and may extend to the end of the effective diameter. That is, the effective area may be an effective area in which the incident light is refracted to achieve optical characteristics. The ineffective area may be arranged around the effective area. The ineffective area may be an area in which effective light from the plurality of lenses 100 is not incident. That is, the ineffective area may be an area that is not related to optical characteristics. In addition, the end of the ineffective area may be an area fixed to a lens barrel (not shown) that houses the lens.

[0081] The optical system 1000 may include an image sensor 300. The image sensor 300 may detect light and convert it into an electrical signal. The image sensor 300 may detect light that sequentially passes through a plurality of lenses 100. The image sensor 300 may include a device capable of sensing incident light, such as a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS).

[0082] The optical system 1000 may include an optical filter 500. The optical filter 500 may be disposed between the second lens group G2 and the image sensor 300. The optical filter 500 may be disposed between a lens closest to the sensor side among the plurality of lenses 100 and the image sensor 300. For example, when the optical system 100 is the last lens, the optical filter 500 may be disposed between the last lens and the image sensor 300.

[0083] The optical filter 500 may include at least one of an infrared filter and a cover glass optical filter. The filter 500 may allow light of a set wavelength band to pass through and filter out light of a different wavelength band. When the optical filter 500 includes an infrared filter, radiant heat emitted from external light may be prevented from being transferred to the image sensor 300. In addition, the optical filter 500 may allow visible light to pass through and reflect infrared light.

[0084] The optical system 1000 according to an embodiment may include an aperture stop ST. The aperture stop ST may control the amount of light incident on the optical system 1000. The aperture stop ST may be disposed around the lenses of the first lens group G1. For example, the aperture stop ST may be disposed around the object-side surface or the sensor-side surface of the first lens 101 closest to the object side. The aperture stop ST may be disposed between two adjacent lenses 101 and 102 among the lenses of the first lens group G1. For example, the aperture stop ST may be located around the sensor-side surface S2 of the first lens 101 closest to the object side. Alternatively, at least one lens selected from the plurality of lenses 100 may be used as an aperture stop. In detail, the object-side surface or the sensor-side surface of one lens selected from the lenses of the first lens group G1 may be used as an aperture stop for adjusting the amount of light.

[0085] The focal length of the first lens group G1 may have a positive value, and the focal length of the second lens group G2 may have a negative value. As an absolute value, the focal length of the second lens group G2 may be greater than the focal length of the first lens group G1. Here, the focal length is the reciprocal of the refractive power.

[0086] The optical system 1000 according to the embodiment may further include a reflective member (not shown) for changing the optical path. The reflective member may be implemented as a prism that reflects the incident light of the first lens group G1 toward the lens. The optical system according to the embodiment will be described in detail below.

[0087] Figure 1 is a structural diagram of an optical system and a camera module according to an embodiment of the present invention, Figure 2 It is shown Figure 1 , an explanatory diagram of the relationship between the image sensor, the n-th lens and the n-1-th lens of the optical system in the first direction Y, Figure 3 It is shown Figure 1, an explanatory diagram of the relationship between the image sensor, the n-th lens and the n-1-th lens of the optical system in the second direction X, Figure 4 is from Figure 1 Plane view of the optical system as seen by the n-1th lens. Figures 5 to 10 is a diagram showing lens data of the optical system according to the first embodiment, Figures 11 to 16 is a diagram showing lens data of an optical system according to a second embodiment, Fig.17 is a view comparing the thickness (L7_T) of the seventh lens in each direction (0 degrees to 90 degrees) from the optical axis to the end of the effective area with respect to the thickness (L7_T) of the seventh lens in the first embodiment and the second embodiment, and Fig.18 : is a graph comparing the SAG height of the sensor-side surface ( L7S2 ) of the seventh lens in the first embodiment and the second embodiment in each direction from the optical axis to the end of the effective area.

[0088] refer to Figures 1 to 4 , Figure 5 and Fig.11 The optical system 1000 according to the embodiment includes a plurality of lenses 100, and the plurality of lenses 100 may include first to seventh lenses 101 to 107. The first to seventh lenses 101 to 107 may be sequentially arranged along the optical axis OA of the optical system 1000, and light corresponding to object information may be received and incident on the image sensor 300.

[0089] The first lens 101 may have a positive (+) refractive power along the optical axis OA. The first lens 101 may include a plastic or glass material. For example, the first lens 101 may be made of a plastic material.

[0090] The first lens 101 may include a first surface S1 defined as an object side surface and a second surface S2 defined as a sensor side surface. On the optical axis OA, the first surface S1 may have a convex shape and the second surface S2 may have a concave shape. That is, the first lens 101 may have a meniscus shape convex from the optical axis OA toward the object side. At least one of the first surface S1 and the second surface S2 may be an aspherical surface. For example, both the first surface S1 and the second surface S2 may be aspherical surfaces. In the first and second embodiments, the aspherical coefficients of the first surface S1 and the second surface S2 are set as follows: Figure 6 and Fig.12 As shown, and can be represented by S1 and S2 of L1.

[0091] The second lens 102 may have positive (+) or negative (-) refractive power on the optical axis OA. The second lens 102 may have positive (+) refractive power. The second lens 102 may include a plastic or glass material. For example, the second lens 102 may be made of a plastic material.

[0092] The second lens 102 may include a third surface S3 defined as an object-side surface and a fourth surface S4 defined as a sensor-side surface. On the optical axis OA, the third surface S3 may have a convex shape and the fourth surface S4 may have a concave shape. That is, the second lens 102 may have a meniscus shape that convexes from the optical axis OA toward the object side. Alternatively, the second lens 102 may have a shape that is convex on both sides or concave on both sides. When expressed in absolute values, the radius of curvature of the fourth surface S4 of the second lens 102 may be the largest in the optical system 1000. At least one of the third surface S3 and the fourth surface S4 may be an aspherical surface. For example, both the third surface S3 and the fourth surface S4 may be aspherical surfaces. In the first and second embodiments, the aspherical coefficients of the third surface S3 and the fourth surface S4 are set as follows Figure 6 and Fig.12 As shown, L2 is the second lens 102, L2S1 is the third surface, and L2S2 is the fourth surface.

[0093] The third lens 103 may have positive (+) or negative (-) refractive power on the optical axis OA, and may preferably have negative (-) refractive power. The third lens 103 may include a plastic or glass material. For example, the third lens 103 may be made of a plastic material.

[0094] 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. On the optical axis OA, the fifth surface S5 may have a convex shape and the sixth surface S6 may have a concave shape. That is, the third lens 103 may have a meniscus shape that convexes from the optical axis OA toward the object side. Alternatively, the third lens 103 may have a shape that is convex on both sides or concave on both sides on the optical axis OA. At least one of the fifth surface S5 and the sixth surface S6 may be an aspherical surface. For example, both the fifth surface S5 and the sixth surface S6 may be aspherical surfaces. In the first and second embodiments, the aspherical coefficients of the fifth surface S5 and the sixth surface S6 are set as follows Figure 6 and Fig.12 As shown, L3 is the third lens 103, L3S1 is the fifth surface, and L3S2 is the sixth surface.

[0095] The first lens group G1 may include first to third lenses 101, 102, and 103. Among the first to third lenses 101, 102, and 103, in the thickness on the optical axis OA (i.e., the center thickness of the lens), the second lens 102 may have the thickest thickness on the optical axis OA, and the third lens 103 may have the thinnest thickness on the optical axis OA. The first to third lenses 101, 102, and 103 may have a meniscus shape convex toward the object side. Therefore, the optical system 1000 may control incident light and may have improved aberration characteristics and resolution.

[0096] Among the first to third lenses 101, 102, and 103, the third lens 103 may have the smallest average effective diameter (CA: clear aperture) among the lenses, and the first lens 101 may have the largest effective diameter. In detail, among the first to third lenses 101, 102, and 103, the effective radius D11 of the first surface S1 may be the largest, and the effective radius of the sixth surface S6 of the third lens 103 may be the smallest. In addition, the size of the effective diameter of the second lens 102 may be smaller than the effective diameter of the first lens 101 and larger than the size of the effective diameter of the third lens 103. The size of the effective diameter of the third lens 103 may be the smallest among the lenses of the optical system 1000. The size of the effective diameter is the average of the size of the effective diameter on the object-side surface of each lens and the size of the effective diameter on the sensor-side surface of each lens. Therefore, the optical system 1000 may have an improved chromatic aberration control characteristic, and the vignetting characteristic of the optical system 1000 may be improved by controlling the incident light.

[0097] The refractive index of the third lens 103 may be greater than the refractive index of at least one or all of the first lens 101 and the second lens 102. The refractive index of the third lens 103 may be greater than 1.6, for example, 1.65 or greater, and the refractive indexes of the first lens 101 and the second lens 102 may be less than 1.6. The Abbe number of the third lens 103 may be less than the Abbe number of at least one or both of the first lens 101 and the second lens 102. For example, the Abbe number of the third lens 103 may be less than the Abbe number of the first lens 101 and the second lens 102, which differ by 20 or more. In detail, the Abbe number of the first lens 101 and the second lens 102 may be greater than the Abbe number of the third lens 103 by 30 or more. Therefore, the optical system 1000 may have improved chromatic aberration control characteristics.

[0098] When the radius of curvature on the optical axis OA is expressed as an absolute value, the radius of curvature of the fourth surface S4 of the second lens 102 may be the largest among the first to third lenses 101, 102, and 103. The radius of curvature of the first surface S1 of the first lens 101 may be the smallest. In the first lens group G1, the difference between the lens surface having the largest radius of curvature and the lens surface having the smallest radius of curvature may be 50 times or more.

[0099] The fourth lens 104 may have positive (+) or negative (-) refractive power on the optical axis OA. The fourth lens 104 may have positive (+) refractive power. The fourth lens 104 may include a plastic or glass material. For example, the fourth lens 104 may be made of a plastic material.

[0100] 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. On the optical axis OA, the seventh surface S7 may have a concave shape, and the eighth surface S8 may have a convex shape. That is, the fourth lens 104 may have a meniscus shape convex from the optical axis OA toward the sensor. Alternatively, the seventh surface S7 may have a convex shape along 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 convex shape on both sides of 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 convex from the optical axis OA toward the object side. Alternatively, the fourth lens 104 may have a concave shape on both sides of the optical axis OA. The seventh surface S7 and the eighth surface S8 of the fourth lens 104 may be arranged so that there is no critical point from the optical axis OA to the end of the effective area. At least one of the seventh surface S7 and the eighth surface S8 may be aspherical. For example, the seventh surface S7 and the eighth surface S8 may both be aspherical surfaces. In the first and second embodiments, the aspherical coefficients of the seventh surface S7 and the eighth surface S8 are set as follows: Figure 6 and Fig.12 As shown, L4 is the fourth lens 104, L4S1 is the seventh surface, and L4S2 is the eighth surface.

[0101] The refractive index of the fourth lens 104 may be smaller than the refractive index of the third lens 103. The Abbe number of the fourth lens 104 may be greater than the Abbe number of the third lens 103, greater than the Abbe number of the fifth lens 105, and less than the Abbe number of the first lens 101. The focal length of the fourth lens 104 may be greater than the focal lengths of the first to third lenses 101, 102, and 103. Therefore, the optical system 1000 may have improved chromatic aberration control characteristics.

[0102] The fifth lens 105 may have positive (+) or negative (-) refractive power on the optical axis OA. The fifth lens 105 may have negative (-) refractive power. The fifth lens 105 may include a plastic or glass material. For example, the fifth lens 105 may be made of a plastic material.

[0103] 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 concave shape on the optical axis OA. That is, the fifth lens 105 may have a concave shape on both sides of the optical axis OA. Alternatively, the fifth lens 106 may have a meniscus shape convex toward the sensor. The ninth surface S9 and the tenth surface S10 of the fifth lens 105 may be arranged to have no critical point from the optical axis OA to the end of the effective area. When the radius of curvature on the optical axis OA is expressed in absolute value, the radius of curvature of the tenth surface S10 may be twice or more times the radius of curvature of the ninth surface S9. The refractive index of the fifth lens 105 may be greater than 1.6, for example, 1.65 or greater, and may be greater than the refractive indexes of the fourth lens 104, the sixth lens 106, and the seventh lens 107. At least one of the ninth surface S9 and the tenth surface S10 may be an aspherical surface. For example, both the ninth surface S9 and the tenth surface S10 may be aspherical surfaces. In the first and second embodiments, the aspheric coefficients of the ninth surface S9 and the tenth surface S10 are set as follows: Figure 6 and Fig.12 As shown, L5 is the fifth lens 105, L5S1 is the ninth surface, and L5S2 is the tenth surface.

[0104] The sixth lens 106 may have positive (+) or negative (-) refractive power on the optical axis OA. The sixth lens 106 may have positive (+) refractive power. The sixth lens 106 may include a plastic or glass material. For example, the sixth lens 106 may be made of a plastic material.

[0105] 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 convex shape on the optical axis OA, and the twelfth surface S12 may have a concave shape on the optical axis OA. That is, the sixth lens 106 may have a meniscus shape convex from the optical axis OA toward the object side. Alternatively, the eleventh surface S11 may have a concave shape on the optical axis OA, and the twelfth surface S12 may have a convex shape on the optical axis OA. That is, the sixth lens 106 may have a meniscus shape convex toward the sensor. At least one or both of the eleventh surface S11 and the twelfth surface S12 may be free-form surfaces. In the first and second embodiments, the polynomial coefficients C1-C80 representing the free-form surfaces of the eleventh surface S11 and the twelfth surface S12 may be calculated according to the following formulas: Figure 7 The first and second embodiments shown are obtained, L6 is the sixth lens 106, L6S1 is the eleventh surface, and L6S2 is the twelfth surface.

[0106] At least one or both of the eleventh surface S11 and the twelfth surface S12 of the sixth lens 106 may have an asymmetric shape of a lens surface in the first direction Y and the second direction X perpendicular to the optical axis OA. At least one or both of the eleventh surface S11 and the twelfth surface S12 are symmetrical about both sides of the first direction Y orthogonal to the optical axis OA, and are symmetrical about both sides of the second direction X. The sixth lens 106 may have different thicknesses within the same radius along the first direction Y and the second direction X orthogonal to the optical axis OA.

[0107] like Figures 2 to 4 As shown, the positions of the critical points P1 and P5 of the eleventh surface S11 of the sixth lens 106 may be equal or different distances InfX61 and InfY61 in the first direction Y and the second direction X orthogonal to the optical axis OA. The positions of the critical points P2 and P6 of the twelfth surface S12 of the sixth lens 106 may be equal or different distances InfX62 and InfY62 in the first direction Y and the second direction X orthogonal to the optical axis OA.

[0108] exist Figure 4 , the average values ​​Inf61 and Inf62 of the critical points are lines showing the average positions of the critical points P1, P2, P5 and P6 in the eleventh surface S11 and the twelfth surface S12 and the optical axis OA, and may be circles having the same radius or different radii according to orthogonal directions.

[0109] like Figure 2 , Figure 3 , Figure 4 , Fig.10 and Fig.16 As shown, the critical points P2 and P6 of the twelfth surface S12 can be located at the same distance at each angle (0 degree, 30 degree, 35 degree, 53 degree, 60 degree, 90 degree) according to the radius of the virtual circle, or at least one of them can be located at different distances. Here, the angle 0 through the optical axis OA represents the first direction X orthogonal to the optical axis OA, the angle 90 represents the second direction Y orthogonal to the optical axis OA and the first direction X, and the angles 30 degrees, 35 degrees, 53 degrees, and 60 degrees are angles from the first direction X to the second direction Y in different directions orthogonal to the optical axis OA. For example, the critical points P2 and P6 of the twelfth surface S12 can have the same or different distances InfX62 and InfY62 in the first direction X (angle 0) and the second direction Y (angle 90). In addition, the distance InfX62 from the optical axis OA to the critical point P2 on the first direction X (angle 0) and the distance to the critical point at any position between 30 degrees and 60 degrees can be different from each other. A distance InfY62 from the optical axis OA to the critical point P6 in the second direction Y and a distance to the critical point at any one of 30 to 60 degrees may be the same as or different from each other.

[0110] The eleventh surface S11 of the sixth lens 106 may have at least one critical point from the optical axis OA to the end of the effective radius, and the twelfth surface S12 may have at least one critical point from the optical axis OA to the end of the effective radius. The critical points P1 and P5 of the eleventh surface S11 may be located at a distance InfX61 and InfY61 of 54% or more of the effective radius D61, and the effective radius D61 is the distance from the optical axis OA to the end of the effective radius, for example, in the range of 54% to 74% or in the range of 59% to 69%. The critical points P2 and P6 of the twelfth surface S12 may be located at a distance InfX62 and InfY62 of 44% or more of the effective radius D62 relative to the optical axis OA, for example, in the range of 44% to 64% or 49% to 59%.

[0111] The positions of the critical points P2 and P6 of the twelfth surface S12 of the sixth lens 106 and the positions of the critical points P1 and P5 of the eleventh surface S11 can be located in the range of 1.7 mm to 2.3 mm relative to the optical axis OA. The critical point P2 of the twelfth surface S12 in the first direction X is set at a position where the distance from the optical axis OA is the same as the distance from the critical point P6 in the second direction Y, or is set at a position where the distance from the critical point P6 in the second direction Y is different by 0.2 mm or less. Therefore, the twelfth surface S12 can diverge the light incident through the eleventh surface S11. The critical point is a point at which the sign of the slope value relative to the optical axis OA and the direction perpendicular to the optical axis OA changes from positive (+) to negative (-) or from negative (-) to positive (+), and can refer to a point where the slope is zero. In addition, the critical point can be a point where the slope value of the tangent line passing through the lens surface decreases after increasing, or a point where the slope value increases after decreasing. Considering the optical characteristics of the optical system 1000, it is preferred that the positions of the critical points P1, P2, P5, and P6 of the sixth lens 106 are set at positions satisfying the above range. In detail, the positions of the critical points preferably satisfy the above range for controlling the optical characteristics of the optical system 1000, such as chromatic aberration, distortion characteristics, aberration characteristics, and resolution. Therefore, the optical path emitted to the image sensor 300 through the lens can be effectively controlled. Therefore, the optical system 1000 according to the embodiment can have improved optical characteristics even in the center and peripheral parts of the FOV.

[0112] The seventh lens 107 may have a negative (-) refractive power on the optical axis OA. The seventh lens 107 may include a plastic or glass material. For example, the seventh lens 107 may be made of a plastic material. The seventh lens 107 may be a lens closest to the sensor side or a last lens in the optical system 1000.

[0113] 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 convex from the optical axis OA toward the object side. Different from this, the thirteenth surface S13 of the seventh lens 107 may be concave on the optical axis OA, and the fourteenth surface S14 may be concave or convex.

[0114] The thirteenth surface S13 may be a free-form surface. The fourteenth surface S14 may be a free-form surface. The free-form surface coefficients of the thirteenth surface S13 and the fourteenth surface S14 are set as follows: Figure 7 and Fig.13 As shown, L7 is the seventh lens 107, S1 of L7 is the thirteenth surface, and S2 is the fourteenth surface. In addition, the polynomial coefficients C1-C80 representing the free-form surfaces of L7S1 and L7S2 can be obtained according to the first embodiment and the second embodiment, as shown in Figure 7 and Fig.13 Therefore, the seventh lens 107 may be a free-form surface lens.

[0115] like Figures 2 to 4 As shown, at least one or both of the thirteenth surface S13 and the fourteenth surface S14 of the seventh lens 107 may be set as free-form surfaces. For example, the thirteenth surface S13 and the fourteenth surface S14 of the seventh lens 107 are free-form surfaces, which have a symmetrical shape (+X, -X) relative to the optical axis OA in a first direction X orthogonal to the optical axis OA, and may have a symmetrical shape (+Y, -Y) in a second direction Y orthogonal to the optical axis OA. That is, as Figure 2 and Figure 3 As shown, the lens surfaces in the +Y and -Y directions on both sides of the second direction Y relative to the XZ plane or the optical axis OA are symmetrical, and the lens surfaces in the +X and -X directions on both sides of the first direction X based on the YZ plane or the optical axis OA are symmetrical. Here, the Z-axis direction is the optical axis direction. The lens surfaces of the thirteenth surface S13 and the fourteenth surface S14 in the first direction X and the second direction Y may be orthogonal to each other, and may have an asymmetric shape relative to the optical axis OA.

[0116] The thirteenth surface S13 and the fourteenth surface S14 of the seventh lens 107 may have at least one critical point from the optical axis OA to the end of the effective area. The critical points P3 and P7 of the thirteenth surface S13 may be located at a first distance InfX71 and a second distance InfY71 less than or equal to 26% of an effective radius D71, where the effective radius D71 is a distance from the optical axis OA to the end of the effective radius, for example, in the range of 6% to 26% or in the range of 11% to 21%.

[0117] The first distance InfX71 and the second distance InfY71 from the critical points P3 and P7 to the thirteenth surface S13 of the seventh lens 107 can be the same distance in the X and Y directions from the optical axis OA on the thirteenth surface S13 or have a difference of 0.1 mm or less. The first distance InfX71 and the second distance InfY71 can be set within a range of 1.1 mm or less from the optical axis OA, for example, within a range of 0.6 mm to 1.1 mm.

[0118] The critical points P4 and P8 of the fourteenth surface S14 of the seventh lens 107 can be located at the third distance InfX72 and the fourth distance InfY72 that are 43% or less of the effective radius D72 based on the optical axis OA in the first direction X and the second direction Y, for example, within a range of 23% to 43% or within a range of 28% to 38%. The positions of the critical points P4 and P8 of the fourteenth surface S14 can be farther from the optical axis OA than the critical points P3 and P7 of the thirteenth surface S13. For example, the critical points P4 and P8 can be spaced 0.5 mm or more from the critical points P3 and P7 toward the edge, for example, within a range of 0.5 mm to 1.5 mm. Therefore, the fourteenth surface S14 can diverge the light incident through the thirteenth surface S13.

[0119] The third distance InfX72 is the distance from the optical axis OA of the fourteenth surface S14 to the critical point P4 in the first direction X, and the fourth distance InfY72 is the distance from the optical axis OA of the fourteenth surface S14 to the critical point P8 in the second direction Y, and can satisfy: InfX72 < InfY72. The difference between the third distance InfX72 and the fourth distance InfY72 can be 0.2 mm or less. The third distance InfX72 and the fourth distance InfY72 can be set within a range of 1.6 mm or more from the optical axis OA, for example, within a range of 1.6 mm to 2.2 mm.

[0120] The effective radius D71 of the thirteenth surface S13 in the first direction X and the second direction Y can be the same. The effective radius D72 of the fourteenth surface S14 in the first direction X and the second direction Y can be the same. In Figure 4 , the average value of the critical points Inf71 and Inf72 represents the average distance of the critical points P3, P4, P7, P8 on the thirteenth surface S13 and the fourteenth surface S14, and can have a circular shape with different radii.

[0121] As Figure 2 , Figure 3 , Figure 4 , Fig.10 and Fig.16In the first and second embodiments, the critical points of the thirteenth surface S13 can be located at the same distance from each other or at at least one different distance from each other according to the angles (0 degrees, 30 degrees, 35 degrees, 53 degrees, 60 degrees, 90 degrees) on the radius of the virtual circle. For example, the critical points P3 and P7 of the thirteenth surface S13 can be at the same distance in the first direction X (angle 0) and the second direction Y (angle 90), and at the same distance at positions that are 30 degrees to 60 degrees different from the first direction X (angle 0).

[0122] As Fig.10 In the first embodiment, the critical points of the fourteenth surface S14 can have different distances at at least one angle (0 degrees, 30 degrees, 35 degrees, 53 degrees, 60 degrees, 90 degrees) according to the radius of the virtual circle. For example, in the fourteenth surface S14, the distance InfX72 from the optical axis OA to the critical point in the first direction X (0 degrees) and the distance from the optical axis OA to the critical point at 30 degrees can be equal to each other. The distance InfY72 from the optical axis OA to the critical point in the second direction Y (90 degrees) on the fourteenth surface S14 can be the same as the distances from the optical axis OA to the critical points at 35 degrees, 53 degrees, and 60 degrees, respectively. The distances from the optical axis OA to the critical points at the angles (0 degrees and 30 degrees) can be different from each other. Therefore, the critical points P4 and P8 in the first direction X and the second direction Y can be at different distances from each other on the optical axis OA, and can satisfy, for example, InfX72 < InfY72. As Fig.16 In the second embodiment, the critical points of the fourteenth surface S14 can be located at the same distance, or can differ from each other by 0.2 mm or less at the angles (0 degrees, 30 degrees, 35 degrees, 53 degrees, 60 degrees, 90 degrees) according to the radius of the virtual circle.

[0123] Considering the optical characteristics of the optical system 1000, it is preferable that the positions of the critical points P3, P4, P7, and P8 of the seventh lens 107 are set at positions that satisfy the above ranges. Specifically, the positions of the critical points preferably satisfy the above ranges to control optical characteristics such as chromatic aberration, distortion characteristics, aberration characteristics, and resolution of the optical system 1000. Therefore, the optical path emitted to the image sensor 300 through the lens can be effectively controlled. Therefore, the optical system 1000 according to the embodiment can have improved optical characteristics even at the center and peripheral portions of the FOV.

[0124] Here, due to the free-form surface characteristics, the radii of curvature of the object-side surface and the sensor-side surface of the sixth lens 106 and the seventh lens 107 can have shapes opposite to those of the lens surfaces of the sixth lens and the seventh lens. For example, as Figure 5 and Fig.11 shown, the radii of curvature of S1 and S2 of the sixth lens 106 and the seventh lens 107 are both negative values, but as Figures 1 to 3As shown, the eleventh surface S11 of the sixth lens 106 may be convex, the twelfth surface S12 may be concave, the thirteenth surface S13 of the seventh lens 1070 may be convex, and the fourteenth surface S14 may be concave.

[0125] like Figure 2 and Figure 3 As shown, normal lines K2 and K4, which are straight lines perpendicular to tangent lines K1 and K3 in the first direction X and the second direction Y passing through any point on the sensor-side surface S14 of the seventh lens 107, may have predetermined angles θ1 and θ2 with the optical axis OA, and the angles θ1 and θ2 in the first direction X and the second direction Y may be different from each other and may be less than 70 degrees at most, for example, in the range of 5 to 69 degrees or in the range of 30 to 65 degrees. Therefore, since the optical axis or paraxial region of the fourteenth surface S14 has the smallest Sag value, a slim optical system may be provided.

[0126] like Figure 2 and Figure 3 As shown, the back focal length (BFL) is the optical axis distance from the image sensor 300 to the seventh lens 107 as the last lens. That is, BFL is the optical axis distance between the image sensor 300 and the sensor-side fourteenth surface S14 of the seventh lens 107. L6_CT is the center thickness or thickness on the optical axis of the sixth lens 106, and L6_ET is the end or edge thickness of the effective area of ​​the sixth lens 106. L7_CT is the center thickness or thickness on the optical axis of the seventh lens 107. D67_CT is the optical axis distance (i.e., center distance) from the center of the sensor-side surface of the sixth lens 106 to the center of the object-side surface of the seventh lens 107. That is, the optical axis distance D67_CT from the center of the sensor-side surface of the sixth lens 106 to the center of the object-side surface of the seventh lens 107 is the distance between the twelfth surface S12 and the thirteenth surface S13 on the optical axis OA. D67_CT may be greater than the optical axis distance between the third lens 103 and the fourth lens 104. D67_CT may be greater than the sum of the center thicknesses of the sixth lens 106 and the seventh lens 107. D67_CT may be 1.8 or more, for example, 1.8 to 2.5 times, of the center thickness of the thickest lens in the optical system 1000 (ie, the second lens 102).

[0127] The second lens group G2 may include fourth to seventh lenses 104, 105, 106, and 107. Among the fourth to seventh lenses 104, 105, 106, and 107, a lens having a maximum center thickness may be smaller than a center distance between the third lens 103 and the fourth lens 104. In the second lens group G2, a lens having a maximum center thickness may be the sixth lens 106, and a lens having a minimum center thickness may be the fifth lens 105. Therefore, the optical system 1000 may control incident light and may have improved aberration characteristics and resolution.

[0128] The average size of the effective diameter (CA: clear aperture) of the lenses among the fourth to seventh lenses 104, 105, 106, and 107 may be the smallest in the fourth lens 104, and the seventh lens 107 may be the largest. In detail, in the second lens group G2, the size of the effective diameter of the seventh surface S7 of the fourth lens 104 may be the smallest, and the size of the effective diameter of the fourteenth surface S14 may be the largest. The size of the effective diameter of the fourteenth surface S14 may be the largest effective diameter in the optical system, and may be 2.2 times the size of the effective diameter of the seventh surface S7. The effective diameter of the seventh lens 107 is set to the maximum so that incident light can be effectively refracted toward the image sensor 300. Therefore, the optical system 1000 may have an improved chromatic aberration control characteristic, and the vignetting characteristic of the optical system 1000 may be improved by controlling the incident light.

[0129] In the second lens group G2, the number of lenses having a refractive index exceeding 1.6 may be smaller than the number of lenses having a refractive index less than 1.6. In the second lens group G2, the number of lenses having an Abbe number greater than 50 may be smaller than the number of lenses having an Abbe number less than 50.

[0130] In the thickness and distance of each lens according to the first embodiment and the second embodiment, as Figure 8 and Fig.14 As shown, the thicknesses of the first to fifth lenses 101, 102, 103, 104, and 105 are represented by L1 to L5, and the distances between two adjacent lenses are represented by D12 (between the first lens and the second lens), D23 (between the second lens and the third lens), D34 (between the third lens and the fourth lens), and D45 (between the fourth lens and the fifth lens), and are values ​​measured at intervals of 0.1 mm to 0.2 mm along the second direction Y orthogonal to the optical axis. The thickness L1 of the first lens 101 may gradually decrease from the optical axis toward the edge, and the center thickness of the first lens 101 may be 1.2 times or more of the edge thickness, for example, 1.2 to 1.6 times.

[0131] The thickness L2 of the second lens 102 may gradually decrease from the optical axis toward the edge, and the center thickness of the second lens 102 may be 1.7 times or more of the edge thickness, for example, 1.7 to 2.3 times. The maximum thickness of the second lens 102 may be greater than the maximum thickness of the first lens 101, and the minimum thickness may be less than the minimum thickness of the first lens 101.

[0132] The distance D12 between the first lens 101 and the second lens 102 may be the largest at the center and the smallest at the edge, and the maximum distance of the distance D12 may be 1.3 times or more of the minimum distance, for example, in the range of 1.3 to 1.7 times. The maximum distance may be greater than the maximum thickness of the first lens 101, and may be less than the maximum thickness of the second lens 102.

[0133] The thickness L3 of the third lens 103 may gradually increase from the optical axis toward the edge, and the edge thickness of the third lens 103 may be 1.1 times or more of the center thickness, for example, in the range of 1.1 times to 1.5 times. The minimum thickness of the third lens 103 may be less than the maximum thickness of the second lens 102, and may be greater than the minimum thickness, and the maximum thickness of the second lens 102 may be less than the maximum thickness of the first lens 101.

[0134] The distance D23 between the second lens 102 and the third lens 103 may be the smallest at the center and the largest at the edge, and the maximum distance of the distance D23 may be 4 or more times the minimum distance, for example, in the range of 4 to 9 times. The maximum value of the distance D23 may be less than the minimum thickness of the first lens 101 and the second lens 102.

[0135] The thickness L4 of the fourth lens 104 may gradually decrease from the optical axis toward the edge, and the center thickness of the fourth lens 104 may be 3 times or less than the edge thickness, for example, in the range of 1.1 times to 3 times. The maximum thickness of the fourth lens 104 may be less than the minimum thickness of the first lens 101, the second lens 102, and the third lens 103.

[0136] The distance D34 between the third lens 103 and the fourth lens 104 may be maximum at the center and minimum at the edge, and the maximum distance of the distance D34 may be 1.1 times or more of the minimum distance, for example, in the range of 1.1 times to 3 times. The maximum value of the distance D34 may be greater than the maximum thickness of the second lens 102, and the maximum thickness of the second lens 102 may be greater than the minimum thickness of the third lens 103 and less than the maximum thickness of the third lens 103.

[0137] The thickness L5 of the fifth lens 105 is the largest in the region of 85%±3% from the optical axis, and gradually decreases toward the optical axis, with the maximum thickness at the edge. The maximum thickness of the fifth lens 105 may be 1.1 times or more of the minimum thickness, for example, in the range of 1.1 times to 2 times. The difference between the minimum thickness and the maximum thickness of the fifth lens 105 may be 0.1 mm or less, and the maximum thickness of the fifth lens 105 may be less than the minimum thickness of the second lens 102.

[0138] The distance D45 between the fourth lens 104 and the fifth lens 105 may be the smallest at the center and the largest at the edge, and the maximum distance of the distance D45 may be 1.01 times or more of the minimum distance, for example, in the range of 1.01 to 1.5 times. The maximum value of the distance D45 may be greater than the maximum thickness of the second lens 102.

[0139] The center thickness of the second lens 102 is the largest among the center thicknesses of the lenses, and the center distance D78_CT between the seventh lens 107 and the eighth lens 108 is the largest among the center distances between the lenses. The center thickness of the third lens 103 is the smallest among the center thicknesses of the lenses, and the center distance between the second lens 102 and the third lens 103 is the smallest among the center distances between the lenses.

[0140] like Fig. 9 and Fig.15 As shown, the thickness of the sixth lens 106 and the seventh lens 107 are represented as L6 and L7, and the distance between two adjacent lenses is represented as D56 (between the fifth lens and the sixth lens) and D67 (between the sixth lens and the seventh lens), and is a value measured at intervals of 0.1 mm to 0.2 mm along the second direction Y orthogonal to the optical axis. Here, the thicknesses L6 and L7 and the distances D56 and D67 are divided into 0 degrees along the first direction X orthogonal to the optical axis OA, 90 degrees along the second direction Y, and 30 degrees, 45 degrees, 53 degrees, and 60 degrees between the first direction X and the second direction Y.

[0141] It can be seen that when the distance D56 is calculated to the third decimal place, it has the same distance from the optical axis OA to a radius less than 0.9 mm, and has different distances in at least one direction from a radius of 0.9 mm or more. The maximum value of the distance D56 can be two or more times the minimum value, for example, in the range of 2 to 4 times. When the distance D56 is calculated to the fourth decimal place, the points with different distances can be located closer to the optical axis, for example, 0.3 mm ± 0.2 mm from the optical axis.

[0142] The thickness L6 of the sixth lens 106 has the same thickness from the optical axis OA to a radius less than 0.7 mm when calculated to the third decimal place, and may have different thicknesses in at least one direction from a radius of 0.7 mm or more. The maximum value of the thickness L6 is located at the edge, the minimum value is located at the center, and the maximum thickness of the thickness L6 may be 1.1 times or more of the minimum thickness, for example, 1.1 times to 3 times. The maximum thickness L6 may be greater than the maximum thickness of the second lens 102, and the minimum thickness L6 may be less than the maximum thickness of the second lens 102. When the thickness L6 is calculated to the fourth decimal place, the point with different thicknesses may be located closer to the optical axis, for example, 0.4 mm ± 0.2 mm from the optical axis.

[0143] The distance D67 between the sixth lens 106 and the seventh lens 107 has the same distance from the optical axis OA to a radius less than 0.1 mm when calculated to the third decimal place, and may have different distances in at least one direction from a radius of 0.1 mm or more. The maximum value of the distance D67 may be within the region of 0.7 mm ± 0.2 mm, and the minimum value of the distance D67 may be within the region of 2.9 mm ± 0.2 mm. The maximum value may be at least 1.5 times the minimum value, for example, within the range of 1.5 to 3 times. The minimum distance D67 may be 0.6 mm or more, for example, the maximum distance D67 may be 1.2 mm or more.

[0144] The thickness L7 of the seventh lens 107, when calculated to the third decimal place, has the same thickness from the optical axis OA to a radius less than 0.7 mm, and may have different thicknesses in at least one direction from a radius of 0.7 mm or more. The maximum thickness L7 is located at the edge of 3.7 mm ± 0.2 mm, the minimum thickness is located at the center, and the maximum thickness may be 2.6 times or more of the minimum thickness, for example, in the range of 2.6 times to 4 times. The maximum thickness L7 may be the largest in the optical system 1000, and the minimum thickness L7 may be less than the maximum thickness of the first lens 101 and greater than the minimum thickness. When the thickness L6 is calculated to the fourth decimal place, the point with different thicknesses may be located closer to the optical axis.

[0145] Fig.17 : is a comparative view of the thickness L7_T of the seventh lens in each direction (0 degree to 90 degrees) from the optical axis to the end of the effective area in the first embodiment and the second embodiment. Figure 7 As shown, from the optical axis (O) toward the end direction of the effective area (horizontal axis), it can be seen that the different thicknesses at each position (vertical axis) are shown at the position on each axial direction (0 degrees, 30 degrees, 45 degrees, 53 degrees, 60 degrees, 90 degrees). Fig.18: is a comparison diagram of the Sag height of the sensor side surface (L7S2) of the seventh lens in each direction from the optical axis to the end of the effective area in the first embodiment and the second embodiment. Figure 8 As shown, from the optical axis (O) toward the end of the effective area (horizontal axis), it can be seen that different heights (vertical axis) are shown at the position in each axial direction (0 degrees, 30 degrees, 45 degrees, 53 degrees, 60 degrees, 90 degrees).

[0146] Since the object-side eleventh surface S11 of the sixth lens 106 has a free-form surface, it can be seen that the distance D56 between the fifth lens 105 and the sixth lens 106 has different distances from each other as the end height (e.g., 2.9 mm) of the effective region is approached in the directions of 30 degrees, 45 degrees, 53 degrees, and 60 degrees toward the second direction Y (90 degrees) based on the first direction X (0 degrees). Therefore, the distance D56 between the fifth lens 105 and the sixth lens 106 has different intervals (e.g., 0.9 mm to 2.9 mm) in different directions relative to the optical axis OA at the same point.

[0147] Since the sensor-side twelfth surface S12 of the sixth lens 106 and the object-side thirteenth surface S13 of the seventh lens 107 have free-form surfaces, it can be seen that the distance D67 between the sixth lens 106 and the seventh lens 107 has different distances from each other as the end height (e.g., 3.7 mm) of the effective area is approached in the directions of 30 degrees, 45 degrees, 53 degrees, and 60 degrees toward the second direction Y (90 degrees) based on the first direction X (0 degrees). Therefore, the distance D56 between the fifth lens 105 and the sixth lens 106 has different intervals (e.g., 0.3 mm to 3.7 mm) in different directions relative to the optical axis OA at the same point.

[0148] The thickness of the sixth lens 106 may have different thicknesses at the same distance from a distance of 0.9 mm or more relative to the optical axis OA to different directions (0 degrees, 30 degrees, 45 degrees, 53 degrees, 60 degrees, 90 degrees) of the end of the effective area. The thickness of the seventh lens 107 may have different thicknesses at the same distance from a distance of 0.7 mm or more relative to the optical axis OA to different directions (0 degrees, 30 degrees, 45 degrees, 53 degrees, 60 degrees, 90 degrees) of the end of the effective area.

[0149] The refractive index of the fifth lens 105 may be greater than the refractive indexes of the sixth lens 106 and the seventh lens 107, and may be greater than 1.6. The Abbe number of the fifth lens 105 may be less than the Abbe number of the sixth lens 106 and the seventh lens 107. For example, the Abbe number of the fifth lens 105 may be 20 or more smaller than the Abbe number of the seventh lens 107. In detail, the Abbe number of the seventh lens 107 may be greater than the Abbe number of the fifth lens 105 by 30 or more, for example, 50 or more. Therefore, the optical system 1000 may have improved chromatic aberration control characteristics.

[0150] The maximum center thickness among the thicknesses of the lenses 101 to 107 may be two or more times, for example, 2 to 5 times, the minimum center thickness. The second lens 102 having the maximum center thickness may be two or more times, for example, 2 to 5 times, the fifth lens 105 having the minimum center thickness. In the plurality of lenses 100, the number of lenses having a center thickness less than 0.5 mm may be greater than the number of lenses having a center thickness of 0.5 mm or greater. Therefore, the optical system 1000 may be provided with a structure having a slim thickness. In the plurality of lens surfaces S1 to S14, the number of surfaces having an effective radius less than 2 mm may be greater than the number of surfaces having an effective radius of 2 mm or greater. Describing the radius of curvature as an absolute value, the radius of curvature of the fourth surface S4 of the second lens 102 in the plurality of lenses 100 may be the largest among the lens surfaces on the optical axis OA, and the radius of curvature of the first surface S1 of the first lens, the first lens 101, may be the smallest among the lens surfaces on the optical axis OA.

[0151] When the focal lengths are described as absolute values, the focal length of the fourth lens 106 among the plurality of lenses 100 may be the largest among the lenses, the focal length of the seventh lens 107 may be the smallest, and the largest focal length among the focal lengths may be greater than four times the smallest focal length.

[0152] The optical system 1000 according to the embodiment disclosed above may satisfy at least one or two or more of the following mathematical formulas. Therefore, the optical system 1000 according to the embodiment may have improved optical characteristics. For example, when the optical system 1000 satisfies at least one mathematical formula, the optical system 1000 may effectively control aberration characteristics such as chromatic aberration and distortion, and may have good optical performance not only in the central part of the FOV but also in the peripheral part. The optical system 1000 may have improved resolution and may have a thinner and more compact structure.

[0153] [Mathematical formula 1]

[0154] 1 <L1_CT / L3_CT<5

[0155] In Math 1, L1_CT represents the thickness (mm) of the first lens 101 on the optical axis OA, and L3_CT represents the thickness (mm) of the third lens 103 on the optical axis OA. When the optical system 1000 satisfies Math 1, the optical system 1000 can improve aberration characteristics. Preferably, the above Math 1 can satisfy: <L1_CT / L3_CT≤3。

[0156] [Mathematical formula 2]

[0157] 0.5 <L3_CT / L4_CT<2

[0158] In Math 2, L3_CT represents the thickness (mm) of the third lens 103 along the optical axis OA, and L4_CT represents the thickness (mm) of the fourth lens 104 along the optical axis OA. When the optical system 1000 satisfies Math 2, the optical system 1000 may have improved chromatic aberration control characteristics. Preferably, the above Math 2 may satisfy: <L3_CT / L4_CT≤1.5。

[0159] [Mathematical formula 2-1]

[0160] (L1_CT+L3_CT)>L2_CT

[0161] In Math 2-1, a thickness L2_CT of the second lens 102 on the optical axis OA may be less than a sum of a center thickness L1_CT of the first lens 101 and a center thickness L3_CT of the third lens 103. When the optical system 1000 satisfies Math 2-1, the optical system 1000 may have improved chromatic aberration control characteristics.

[0162] [Mathematical formula 3]

[0163] 1 <L7_CT / L6_CT<2

[0164] In Math 3, L7_CT represents the thickness (mm) of the seventh lens 107 on the optical axis OA, and L6_CT represents the thickness (mm) of the sixth lens 106 on the optical axis OA. In detail, when the optical system 1000 satisfies Math 3, the optical system 1000 may have improved chromatic aberration control characteristics.

[0165] [Formula 4]

[0166] 0.1 <L1_CT / L7_CT<3

[0167] [Formula 5]

[0168] 0 <L7_CT / L2_CT<1

[0169] [Mathematical formula 6]

[0170] 1 < L2_CT / L3_CT < 3.0

[0171] When the optical system 1000 satisfies Mathematical Expressions 4 to 6, the optical system 1000 can have improved chromatic aberration control characteristics. Therefore, the thicknesses of the first lens 101, the second lens 102, and the seventh lens 107 can satisfy: L8_CT < L1_CT < L2_CT and L3_CT < L1_CT < L2_CT.

[0172] [Mathematical Expression 7]

[0173] 0.01 < D12_CT / D67_CT < 1

[0174] In Mathematical Expression 7, D12_CT represents the optical axis distance (mm) between the first lens 101 and the second lens 102. Specifically, D12_CT represents the distance (mm) on the optical axis OA between the second surface S2 of the first lens 101 and the third surface S3 of the second lens 102. D67_CT represents the optical axis distance (mm) between the center of the twelfth surface S12 of the sixth lens 106 and the center of the thirteenth surface S13 of the seventh lens 107. When the optical system 1000 according to the embodiment satisfies Mathematical Expression 7, the optical system 1000 can improve the aberration characteristics and control the size of the optical system 1000, such as reducing TTL. Preferably, Mathematical Expression 7 can satisfy: 0.01 < D12_CT / D67_CT ≤ 0.5.

[0175] [Mathematical Expression 8]

[0176] 1 < G1_TD / D34_CT < 5

[0177] In Mathematical Expression 8, G1_TD represents the optical axis distance (mm) between the first object-side surface S1 of the first lens 101 and the sensor-side sixth surface S6 of the third lens 103. D34_CT represents the optical axis distance (mm) between the third lens 103 and the fourth lens 104. When the optical system 1000 satisfies Mathematical Expression 8, the thickness of the first lens group G1 and the optical axis distance between the second lens group G2 can be set, and the aberration characteristics of the optical system 1000 can be improved, and the reduction of TTL can be controlled.

[0178] [Mathematical Expression 9]

[0179] 1 < G2_TD / D67_CT < 5

[0180] In Math 8, G2_TD represents the optical axis distance (mm) between the seventh object side surface S7 of the fourth lens 104 and the fourteenth sensor side surface S14 of the seventh lens 107. D67_CT represents the optical axis distance (mm) between the sixth lens 106 and the seventh lens 107. Math 9 may set the total optical axis distance of the second lens group G2 and the maximum distance within the second lens group G2. When the optical system 1000 according to the embodiment satisfies Math 9, the optical system 1000 may improve aberration characteristics and control the size of the optical system 1000, such as TTL reduction. Preferably, the value of Math 8 may be 2 or more and 4 or less.

[0181] In addition, Mathematical Formula 8 and / or Mathematical Formula 9 may also satisfy at least one of the following Mathematical Formulas 9-1 to 9-7.

[0182] [Mathematical formula 9-1] G1_TD <G2_TD

[0183] [Mathematical formula 9-2]D34_CT <D67_CT

[0184] [Mathematical formula 9-3] G1_TD>D67_CT

[0185] [Mathematical formula 9-4]1 <G2_TD / G1_TD<4

[0186] [Mathematical formula 9-5]1 <nL / D67_CT<3

[0187] Here, nL is the number of lenses in the optical system 1000 , and may be in the range of 6 to 8 or 7, for example.

[0188] [Mathematical formula 9-6]2 <nL / G2_TD<5

[0189] [Mathematical formula 9-7]1 <nL / G1_TD<3

[0190] [Formula 10]

[0191] 0<(L6_CT+L7_CT) / D67_CT<1

[0192] In Math 10, the sum of the center thickness L6_CT of the sixth lens 106 and the center thickness L7_CT of the seventh lens 107 may be less than the optical axis distance D67_CT between the sixth lens 106 and the seventh lens 107. When the optical system 1000 satisfies Math 10, the optical system 1000 may improve aberration characteristics and control TTL slimness.

[0193] [Mathematical formula 11]

[0194] 0 <L1R1 / L7R2<5

[0195] In Math Formula 11, L1R1 represents a curvature radius (mm) of the first surface S1 of the first lens 101 on the optical axis OA, and L7R2 represents a curvature radius (mm) of the fourteenth surface S14 of the seventh lens 107 on the optical axis OA. When the optical system 1000 according to the embodiment satisfies Math Formula 11, optical performance may be improved by controlling the shapes and refractive powers of the first lens and the seventh lens.

[0196] Regarding the surface shape, refractive power, and optical performance of the lens of the optical system 1000, Math. 11 may further include at least one of Math. 11-1 to 11-3.

[0197] [Mathematical formula 11-1] 1<|L5R1 / L7R2|<30

[0198] In Math 10-1, L5R1 represents a radius of curvature (mm) of a ninth surface S9 of the fifth lens 105 on the optical axis OA. When Math 11-1 is satisfied, shapes and refractive powers of the fifth and seventh lenses may be controlled, and optical performance of the second lens group G2 may be improved.

[0199] [Mathematical formula 11-2] 1<|L5R1 / L6R2|<10

[0200] In Math Formula 11-2, L6R2 represents a curvature radius (mm) of the twelfth surface S12 of the sixth lens 106 on the optical axis OA. When Math Formula 11-2 is satisfied, the shapes and refractive powers of the fifth and sixth lenses may be controlled.

[0201] [Mathematical formula 11-3] 0<|L5R1 / L2R2|<1

[0202] In Math Formula 11-3, L2R2 represents a radius of curvature (mm) of the fourth surface S4 of the second lens 102 on the optical axis OA. When Math Formula 11-3 is satisfied, the shapes and refractive powers of the second lens and the fifth lens may be controlled.

[0203] Here, the fourth surface S4 of the second lens 102 has the largest curvature radius, and its absolute value may exceed 100, while the absolute values ​​of the curvature radiuses of the ninth surface S9 of the fifth lens 105 and the twelfth surface S12 of the sixth lens 106 may be less than 100, and may satisfy: L2R2>L5R1>L6R2.

[0204] [Mathematical formula 12]

[0205] 10<(|L5R1| / L2_CT) / nL<90

[0206] When Math Formula 12 is satisfied, the refractive powers of the second lens and the fifth lens may be controlled, and optical properties of incident light may be improved.

[0207] Math 12 may further include at least one of the following Math 12-1 to Math 12-2.

[0208] [Mathematical formula 12-1]

[0209] 10<(L_R_Max / L_CT_Max) / nL<90

[0210] In Math Formula 12-1, L_R_Max is the maximum radius of curvature of the first to sixteenth surfaces S1 - S16 on the optical axis (OA), and L_CT_Max is the maximum thickness of the first to seventh lenses 101 to 107 on the optical axis.

[0211] [Mathematical formula 12-2]

[0212] 10<(L_R2_Max / L_CT_Max) / nL<90

[0213] In Math Formula 12-2, L_R2_Max is the maximum value of the curvature radius R2 of the sensor-side surface of the first to seventh lenses 101 to 107 , and nL is the number of lenses in the optical system 1000 .

[0214] [Mathematical formula 13]

[0215] 0 <D6_CT / D67_CT<1

[0216] Math 13 may set the thickness D6_CT of the sixth lens 106 on the optical axis and the distance D67_CT between the sixth lens 106 and the seventh lens 107 on the optical axis. When the optical system satisfies Math 13, the optical system 1000 may improve aberration characteristics and control the size of the optical system 1000, such as TTL reduction.

[0217] [Formula 14]

[0218] 0<(D67_CT) / InfX72<1.2

[0219] In Math 14, D67_CT is the optical axis distance between the sixth lens 106 and the seventh lens 107, and InfX72 is the straight line distance (mm) from the optical axis OA to the critical point P8 in the X-axis direction on the sensor side surface S14 of the seventh lens 107. The critical point P8 may be the first critical point in the X-axis direction adjacent to the optical axis OA. When the optical system satisfies Math 14, the optical performance of the optical system having a free-form surface lens, for example, the distortion aberration characteristics of the peripheral portion in the X-axis direction, may be improved. Preferably, the value of Math 14 may be 0.5 or more and 1 or less.

[0220] [Mathematical formula 15]

[0221] 0<(D67_CT) / InfY72<1.2

[0222] In mathematical formula 15, InfY72 is the straight-line distance (mm) from the optical axis OA to the critical point P4 in the Y-axis direction on the sensor side surface S14 of the seventh lens 107. The critical point P4 may be the first critical point in the Y-axis direction adjacent to the optical axis OA. When the optical system satisfies mathematical formula 15, optical performance, such as distortion aberration characteristics of the peripheral part in the Y-axis direction, may be improved. Preferably, the value of mathematical formula 15 may be 0.5 or greater and 1 or less, and may have a difference of 0.2 or less from the value of mathematical formula 14. In addition, InfX72 and InfY72 may be different from each other, and the difference may be less than 0.5 mm.

[0223] [Formula 16]

[0224] 0<(D67_CT) / Inf72<1.2

[0225] In Math 16, Inf72 is an average value of a straight-line distance (mm) from the optical axis OA to a critical point P4 in the Y-axis direction on the sensor-side surface S14 of the seventh lens 107 and a distance from the optical axis to a critical point P8 in the X-axis direction. When the optical system satisfies Math 16, optical performance, for example, distortion aberration characteristics of peripheral portions in the X-axis direction and the Y-axis direction can be improved.

[0226] [Mathematical formula 17]

[0227] 1.60 <n3

[0228] In Math 17, n3 represents the refractive index of the third lens 103 at the d-line. When the optical system 1000 according to the embodiment satisfies Math 17, the optical system 1000 may improve chromatic aberration characteristics.

[0229] Math 17 may include at least one of the following Math 17-1 to Math 17-5.

[0230] [Mathematical formula 17-1] 1.50 <n1<1.6

[0231] [Mathematical formula 17-2] 1.50 <n7<1.6

[0232] [Mathematical formula 17-3] 1.52<∑Index / nL<1.62

[0233] [Mathematical formula 17-4] 1.52<∑Index / TTL<1.62

[0234] [Mathematical formula 17-5] 1.52<∑Index / Imgh<1.62

[0235] In Mathematical Formulas 17-1 to 17-5, n1 is the refractive index of the first lens 101 at the d-line, n7 is the refractive index of the seventh lens 107 at the d-line, ∑Index is the sum of the refractive indices of the first lens to the seventh lens, TTL is the optical axis distance from the object side surface of the first lens to the image sensor, and Imgh represents 1 / 2 of the diagonal length of the image sensor. When the optical system 1000 according to the embodiment satisfies at least one of Mathematical Formulas 17-1 to 17-5, the chromatic aberration characteristics can be improved.

[0236] [Mathematical formula 18]

[0237] 0.5 <n2 / n3<1.2

[0238] n2 is the refractive index of the second lens 102 at the d-line, and n3 is the refractive index of the third lens 103 at the d-line. When Mathematical Formula 18 is satisfied, the lens resolution can be adjusted.

[0239] [Mathematical formula 19]

[0240] 1.65 <AVR(n3,n5)<1.75

[0241] In Math 19, n5 represents the refractive index of the fifth lens 105 at the d-line, and AVR(n3, n5) represents the average refractive index of the third lens 103 and the fifth lens 105. When the optical system 1000 according to the embodiment satisfies Math 19, the optical system 1000 may improve chromatic aberration characteristics.

[0242] [Mathematical formula 20]

[0243] 1 <CA_L1S1 / CA_L3S1<2

[0244] In Math 20, CA_L1S1 represents the size (mm) of the effective diameter CA (clear aperture) of the first surface S1 of the first lens 101, and CA_L3S1 represents the size (mm) of the effective diameter CA of the fifth surface S5 of the third lens 103. When the optical system 1000 according to the embodiment satisfies Math 20, the optical system 1000 can control light incident to the first lens group G1 and can have improved aberration control characteristics. The value of Math 20 may be 1.5 or less.

[0245] [Mathematical formula 21]

[0246] 1 <CA_L7S2 / CA_L4S2<5

[0247] In Math 21, CA_L4S2 represents an effective diameter CA (mm) of the eighth surface S8 of the fourth lens 104, and CA_L7S2 represents an effective diameter CA (mm) of the fourteenth surface S14 of the seventh lens 107. When the optical system 1000 according to the embodiment satisfies Math 19, the optical system 1000 can control the path of light traveling through the second lens group G2, and can have improved aberration control characteristics. The value of Math 21 may be 4 or less.

[0248] [Mathematical formula 22]

[0249] 0.2 <CA_L3S2 / CA_L4S1<2

[0250] In Math 20, CA_L3S2 represents the size (mm) of the effective diameter CA of the sixth surface S6 of the third lens 103, and CA_L4S1 represents the size (mm) of the effective diameter CA of the seventh surface S7 of the fourth lens 104. When the optical system 1000 according to the embodiment satisfies Math 22, the optical system 1000 can improve chromatic aberration, and the lengths of the lens surfaces of the first lens group G1 and the second lens group G2 opposite to each other can be set, and vignetting can be controlled to obtain optical performance.

[0251] [Mathematical formula 23]

[0252] 0.1 <CA_L5S2 / CA_L7S2<2

[0253] In Math 23, CA_L5S2 represents a size (mm) of an effective diameter CA of the tenth surface S10 of the fifth lens 105. When the optical system 1000 according to the embodiment satisfies Math 23, the optical system 1000 can control light traveling to the fifth to seventh lenses 105, 106, and 107, and can improve aberration characteristics.

[0254] [Mathematical formula 24]

[0255] 1<|L6R1 / L6_CT|<30

[0256] In Math 24, L6R1 represents the radius of curvature (mm) of the eleventh surface S11 of the sixth lens 106, and L6_CT represents the thickness of the sixth lens 106 on the optical axis. That is, Math 22 may satisfy: L6R1>L6_CT, and the value of Math 24 may be 5 or more and 20 or less. When the optical system 1000 according to the embodiment satisfies Math 24, the aberration characteristics of the optical system 1000 may be improved.

[0257] [Mathematical formula 25]

[0258] 1<|L5R1 / L7R1|<5

[0259] In Math 25, L5R1 represents a curvature radius (mm) of a ninth surface S9 of the fifth lens 105, and L7R1 represents a curvature radius (mm) of a thirteenth surface S13 of the seventh lens 107. When the optical system 1000 according to the embodiment satisfies Math 25, aberration characteristics of the optical system 1000 may be improved. The value of Math 25 may be 10 or less.

[0260] [Mathematical formula 26]

[0261] 0 <L2R1 / |L2R2|<0.5

[0262] [Mathematical formula 27]

[0263] 0<|L3R2 / L3R1|<1

[0264] In Math. 26 and 27, L2R1 and L2R2 represent the curvature radii (mm) of the third surface S3 and the fourth surface S4 of the second lens 102, and L3R1 and L3R2 represent the curvature radii (mm) of the fifth surface S5 and the sixth surface S6. When the optical system 1000 satisfies Math. 26 and 27, the aberration characteristics of the optical system 1000 may be improved. The values ​​of Math. 16 and 27 may be 1 or less.

[0265] [Mathematical formula 28]

[0266] 0≤|EFLX-EFLY|≤0.1

[0267] In Math 28, EFLX is the effective focal length of the optical system in the first direction X, and EFLY is the effective focal length of the optical system in the second direction Y. EFLX and EFLY may be different from each other. In an optical system having a free-form surface lens, the focal lengths in two directions orthogonal to the optical axis OA may be equal to or different from each other. For example, the value of Math 28 may be greater than zero.

[0268] [Mathematical formula 28-1]

[0269] 0≤F27_X / F27_Y≤0.1or0 <F27_X / F27_Y≤0.1

[0270] [Mathematical formula 28-2]

[0271] F12 <F27_X

[0272] F12 <F27_Y

[0273] [Mathematical formula 28-3]

[0274] F47_X≠F47_Y

[0275] F47_X <F47_Y

[0276] In Math 28-1, F27_X and F27_Y are the combined focal lengths of the second lens to the seventh lens in the first direction X and the second direction Y, which may be the same or different. In Math 28-2, F12 is the combined focal length of the first lens and the second lens. In Math 28-3, F47_X and F47_Y are the combined focal lengths of the fourth lens to the seventh lens in the first direction X and the second direction Y.

[0277] [Mathematical formula 29]

[0278] 0 <L_CT_Max / Air_CT_Max<5

[0279] In Math 29, L_CT_Max represents the thickest thickness (mm) of each of the plurality of lenses on the optical axis OA, and Air_CT_Max represents the maximum value of the optical axis interval between the plurality of lenses. When the optical system 1000 according to the embodiment satisfies Math 29, the optical system 1000 has good optical performance at a set FOV and focal length, and the size of the optical system 1000, such as the size of a TTL, can be reduced. The value of Math 29 may be 3 or less, or 1 or less.

[0280] [Mathematical formula 29-1]

[0281] 0 <L_CT_Max / nL<0.5

[0282] [Mathematical formula 29-2]

[0283] 0.2 <Air_CT_Max / nL<0.5

[0284] [Mathematical formula 29-3]

[0285] 0 <L_CT_Max / TTL<0.5

[0286] [Mathematical formula 29-4]

[0287] 0.2 <Air_CT_Max / Imgh<0.5

[0288] Math 29 may include at least one of Math 29-1 to Math 29-4.

[0289] [Math 30]

[0290] 0.5<ΣL_CT / ΣAir_CT<2

[0291] In mathematical formula 30, ∑L_CT represents the sum of the thickness of each of the plurality of lenses on the optical axis OA (mm), and ∑Air_CT represents the sum of the distances between two adjacent lenses of the plurality of lenses on the optical axis OA (mm). When the optical system 1000 according to the embodiment satisfies formula 30, the optical system 1000 has good optical performance under the set FOV and focal length, and the size of the optical system 1000, such as the size of a TTL, can be reduced.

[0292] [Mathematical formula 30-1]

[0293] 0<∑L_CT / nL<0.7

[0294] [Mathematical formula 30-2]

[0295] 0.2<∑Air_CT / nL<0.8

[0296] [Mathematical formula 30-3]

[0297] 0<∑L_CT / TTL<0.7

[0298] [Mathematical formula 30-4]

[0299] 0<∑Air_CT / TTL<0.9

[0300] [Mathematical formula 30-5]

[0301] 0.2<∑L_CT / Imgh<0.7

[0302] [Mathematical formula 30-6]

[0303] 0.2<∑Air_CT / Imgh<0.9

[0304] Mathematical formula 30 may include at least one or two or more of Mathematical formulas 30 - 1 to 30 - 6 .

[0305] [Mathematical formula 31]

[0306] 9<∑Index<20

[0307] In Math Formula 31, ΣIndex represents the sum of the refractive index of each d-line of the plurality of lenses 100. When the optical system 1000 according to the embodiment satisfies Math Formula 31, the TTL of the optical system 1000 may be controlled and the resolution may be improved.

[0308] [Math 32]

[0309] 10<∑Abb / ∑Index<50

[0310] In Math Formula 32, ΣAbbe represents the sum of the Abbe numbers of each of the plurality of lenses 100. When the optical system 1000 according to the embodiment satisfies Math Formula 32, the optical system 1000 may have improved aberration characteristics and resolution.

[0311] Math 32 may also satisfy at least one of Math 32-1 to Math 32-3.

[0312] [Mathematical formula 32-1] 20 < (∑Abb + ∑Index) / nL < 50

[0313] [Mathematical formula 32-2]30<∑Abb / nL<50

[0314] [Mathematical formula 32-3] 30<∑Abb / TTL<50

[0315] [Mathematical formula 32-4] 30<∑Abb / Imgh<50

[0316] ΣAbbe represents the sum of the Abbe numbers of each lens in the plurality of lenses 100 , and nL is the number of lenses in the optical system, which may be in the range of 6 to 8, or, for example, 8.

[0317] [Mathematical formula 33]

[0318] 0.5 <CA_L1S1 / CA_min<2

[0319] In Math 33, CA_L1S1 represents an effective diameter (mm) of the first surface S1 of the first lens 101, and CA_Min represents a minimum effective diameter (mm) of the first to fourteenth surfaces S1-S14. When the optical system 1000 according to the embodiment satisfies Math 33, light incident through the first lens 101 can be controlled, and a slim optical system can be provided while maintaining optical performance.

[0320] [Math 34]

[0321] 1 <CA_max / CA_min<5

[0322] In Math 34, CA_max represents the maximum effective diameter (mm) among the object-side surface and the sensor-side surface of the plurality of lenses, and represents the maximum effective diameter (mm) among the first to fourteenth surfaces S1-S14. When the optical system 1000 according to the embodiment satisfies Math 34, the optical system 1000 can provide a slim and compact optical system while maintaining optical performance. The effective diameter of the fourteenth surface S14 can have the maximum effective diameter, and the effective diameter of the sixth surface S6 can have the minimum effective diameter.

[0323] Mathematical formula 34 may include at least one of mathematical formula 34 - 1 to mathematical formula 34 - 4 .

[0324] [Mathematical formula 34-1]1 <CA_L8 / CA_L3<5

[0325] [Mathematical formula 34-2]1 <CA_L8 / CA_L4<5

[0326] [Mathematical formula 34-3]1 <CA_L8 / CA_L2<5

[0327] [Mathematical formula 34-4]CA_L3 <CA_L4<CA_L2<CA_L5

[0328] Here, CA_L2, CA_L3, CA_L4, CA_L5, and CA_L8 are average values ​​of effective diameters of the object-side surface and the sensor-side surface of each lens. When the optical system satisfies Mathematical Formulas 34-1 to 34-4, the optical system 1000 can provide a slim and compact optical system while maintaining optical performance.

[0329] [Mathematical formula 35]

[0330] 1 <CA_max / CA_AVR<3

[0331] In Math 35, CA_max represents the maximum effective diameter (mm) among the object-side surface and the sensor-side surface of the plurality of lenses, and CA_AVR represents the average of the effective diameters of the object-side surface and the sensor-side surface of the plurality of lenses. When the optical system 1000 according to the embodiment satisfies Math 35, a slim and compact optical system can be provided.

[0332] [Mathematical formula 36]

[0333] 0.1 <CA_min / CA_AVR<1

[0334] In Math 36, CA_min represents the smallest effective diameter (mm) among the object-side surface and the sensor-side surface of the plurality of lenses. When the optical system 1000 according to the embodiment satisfies Math 36, a slim and compact optical system may be provided.

[0335] [Mathematical formula 37]

[0336] 0.1 <CA_max / (2*ImgH)<1

[0337] In Math 37, CA_max represents the largest effective diameter on the object side and the sensor side of the plurality of lenses, and ImgH represents the distance (mm) from the center (0.0F) of the image sensor 300 overlapping the optical axis OA to the diagonal end (1.0F). That is, ImgH represents 1 / 2 of the maximum diagonal length (mm) of the effective area of ​​the image sensor 300. When the optical system 1000 according to the embodiment satisfies Math 37, the optical system 1000 has good optical performance in the center and peripheral parts of the FOV, and a slim and compact optical system can be provided. Here, * represents multiplication.

[0338] Math 37 may include the following Math 37-1 and Math 37-2.

[0339] [Mathematical formula 37-1] 0.5 <ImgH / nL<2

[0340] [Mathematical formula 37-2] 0.5 <TTL / nL<2

[0341] nL is the number of lenses of the optical system, for example, 6 to 8, preferably 7, and TTL represents the distance (mm) from the vertex of the first surface S1 of the first lens 101 to the image surface of the image sensor 300 on the optical axis OA.

[0342] [Math 38]

[0343] 0.5 <TD / CA_max<1.5

[0344] In Math 38, TD is an optical axis distance (mm) from the object-side surface of the first lens 101 to the n-th lens (i.e., the sensor-side surface of the eighth lens 108). For example, it is a distance from the first surface S1 to the sixteenth surface S16 on the optical axis OA. When the optical system 1000 according to the embodiment satisfies Math 38, a slim and compact optical system can be provided.

[0345] [Math 39]

[0346] 0 <F / L7R2<10

[0347] In Math Formula 39, F represents the total focal length of the optical system 1000 (mm), and L7R2 represents the curvature radius (mm) of the fourteenth surface S14 of the seventh lens 107 having a free-form surface. When the optical system 1000 according to the embodiment satisfies Math Formula 39, the optical system 1000 can reduce the size of the optical system 1000, for example, reduce TTL.

[0348] [Math 40]

[0349] 1 <F / L1R1<10

[0350] In Formula 40, L1R1 represents the radius of curvature (mm) of the first surface S1 of the first lens 101. When the optical system 1000 according to the embodiment satisfies Formula 40, the size of the optical system 1000 can be reduced, for example, TTL can be reduced. The value of Formula 40 may be 5 or less, for example, 3 or less.

[0351] [Mathematical formula 41]

[0352] 0 <EPD / L7R2<10

[0353] In Math 41, EPD represents the size (mm) of the entrance pupil of the optical system 1000, and L7R2 represents the radius of curvature (mm) of the fourteenth surface S14 of the seventh lens 107 having a free-form surface. When the optical system 1000 according to the embodiment satisfies Math 41, the optical system 1000 can control the overall brightness and can have good optical performance in the center and peripheral parts of the FOV. The value of Math 41 may be 5 or less, for example, 3 or less.

[0354] [Mathematical formula 42]

[0355] 0.5 <EPD / L1R1<8

[0356] Math 42 represents the relationship between the size of an entrance pupil (EPD) of the optical system and the radius of curvature of the first surface S1 of the first lens 101 and can control incident light. The value of Math 42 may be 5 or less, for example, 3 or less.

[0357] [Mathematical formula 43]

[0358] -3 <F1 / F3<0

[0359] In Math Formula 43, F1 represents the focal length (mm) of the first lens 101, and F3 represents the focal length (mm) of the third lens 103. When the optical system 1000 according to the embodiment satisfies Math Formula 43, it may have appropriate refractive power to control the light path traveling through the first lens 101 and the third lens 103 and improve resolution.

[0360] [Mathematical formula 44]

[0361] 0 <F13 / F<5

[0362] In Math 44, F13 represents the combined focal length of the first to third lenses (mm), and F represents the effective focal length (mm) in two directions X and Y orthogonal to the optical axis OA in the optical system 1000. That is, the effective focal length Fx in the X direction and the effective focal length Fy in the Y direction are different from each other, and their average value can be defined as F. Math 44 establishes a relationship between the focal length of the first lens group G1 and the total effective focal length. When the optical system 1000 according to the embodiment satisfies Math 44, the optical system 1000 can control the TTL of the optical system 1000.

[0363] [Mathematical formula 45]

[0364] 0<|F47 / F13|<10

[0365] In Math 45, F13 represents the composite focal length (mm) of the first lens to the third lens, and F47 represents the composite focal length (mm) of the fourth lens to the seventh lens. Math 45 establishes a relationship between the focal length of the first lens group G1 and the focal length of the second lens group G2. In an embodiment, the composite focal length of the first lens to the third lens may have a positive (+) value, and the composite focal length of the fourth lens to the seventh lens may have a negative (-) value. When the optical system 1000 according to an embodiment satisfies Math 45, the optical system 1000 may improve aberration characteristics such as chromatic aberration and distortion. The value of Math 45 may be 8 or less, for example, 5 or less.

[0366] At least one of Math 44 and Math 45 may include Math 45 - 1 to Math 45 - 4 .

[0367] [Mathematical formula 45-1]-10 <F47 / F<0

[0368] [Mathematical formula 45-2]0 <F / nL<2

[0369] [Mathematical formula 45-3]1<(F13+|F47|+F) / nL<5

[0370] [Mathematical formula 45-4] 0.5 < (F13 + |F47|) / nL < 4

[0371] Here, nL is the number of lenses in the optical system and may be in the range of 6 to 8, or 8.

[0372] [Mathematical formula 46]

[0373] 0.5 <F2 / F<1.5

[0374] In Math 46, F2 is the focal length of the second lens 102, and F is the average of the effective focal lengths of the optical system in the X direction and the Y direction. When Math 46 is satisfied, the optical system and the camera module can improve the chromatic aberration characteristics by setting the ratio of the average effective focal lengths in two directions X and Y orthogonal to the second lens and the optical axis within a set range.

[0375] Math 46 may include at least one of the following Math 46-1 to Math 46-6.

[0376] [Mathematical formula 46-1] 1.5 <F1 / F<3.2

[0377] [Mathematical formula 46-2] 0.5 <F3 / F<2

[0378] [Mathematical formula 46-3]-5 <F4 / F<0

[0379] [Mathematical formula 46-4]1 <F5 / F<10

[0380] [Mathematical formula 46-5]-2.5 <F6 / F<0

[0381] [Mathematical formula 46-6] 0.5 <F7 / F<3

[0382] [Mathematical formula 46-7] -1.5 <F8 / F<0

[0383] In mathematical formulas 46-1 to 46-7, F1, F3, F4, and F5 are the focal lengths of the first lens and the second lens, F6 and F7 are the average effective focal lengths of the sixth lens and the seventh lens in the X and Y directions, and F is the average effective focal length of the optical system in the X and Y directions. When the optical system satisfies mathematical formulas 36, 46-1 to 46-6, the ratio of the average effective focal length of each lens in two directions X and Y orthogonal to the optical axis is set within a set range, and distortion and chromatic aberration characteristics can be improved.

[0384] [Mathematical formula 47]

[0385] -5 <F2 / F3<0

[0386] The optical system can improve distortion and chromatic aberration characteristics by setting the ratio of the focal lengths of the second lens and the third lens to a set range according to Math. 47.

[0387] [Mathematical formula 48]

[0388] 0.8 <F2 / F12<1.8

[0389] In Math 48, F12 is a composite focal length of the first lens and the second lens. The optical system can improve distortion and chromatic aberration characteristics of the first lens group G1 by setting the ratio of the focal lengths of the first lens and the second lens to a set range according to Math 48.

[0390] [Math 49]

[0391] 0.5 <F12 / F<1.5

[0392] When Math Formula 49 is satisfied, the optical system sets the ratio of the combined focal length of the first lens and the second lens to the average effective focal length in two directions X and Y orthogonal to the optical axis to a set range, thereby improving calculated distortion and chromatic aberration characteristics.

[0393] [Mathematical formula 50]

[0394] 1 <F27 / F<4

[0395] When the optical system satisfies mathematical formula 50, the ratio of the average value of the average effective focal length F in two directions X and Y orthogonal to the optical axis to the composite focal length of lens 2-7 is set to a set range, which can improve distortion and chromatic aberration characteristics.

[0396] [Mathematical formula 51]

[0397] 2 <TTL<20

[0398] In Math. 51, TTL represents a distance (mm) on the optical axis OA from the center of the first surface S1 of the first lens 101 to the image surface of the image sensor 300. By setting TTL to less than 20 in Math. 51, a slim and compact optical system can be provided.

[0399] Mathematical formula 51 may also include mathematical formula 51-1.

[0400] [Mathematical formula 51-1] 1<(TTL+Imgh) / nL<5

[0401] Here, nL is the number of lenses in the optical system and may be 6 to 8, preferably 7.

[0402] [Mathematical formula 52]

[0403] 2 <ImgH

[0404] Equation 52 can provide an optical system with high resolution by making the diagonal dimension of the image sensor 300 exceed 4 mm. ImgH can be greater than 4 mm.

[0405] [Mathematical formula 53]

[0406] BFL<2.5

[0407] Mathematical formula 53 can ensure the installation space of the filter 50 by making the BFL (back focal length) less than 2.5 mm, improve the assembly of components and increase the coupling reliability by the distance (mm) between the image sensor 300 and the last lens. That is, when there is no critical point on the sensor side surface of the last lens, the BFL value can be set to be less than 2.5 mm, that is, 2 mm or less.

[0408] [Mathematical formula 54]

[0409] 2 <F<20

[0410] In Math Formula 54, the average values ​​of the first and second directions of the total focal length F may be set according to the optical system.

[0411] [Mathematical formula 55]

[0412] FOV<120

[0413] In Math. 55, FOV represents the angle of view (degree of view) of the optical system 1000, and an optical system with an angle of view less than 120 degrees may be provided. The FOV may be 100 degrees or less.

[0414] [Mathematical formula 56]

[0415] 0.5 <TTL / CA_max<2

[0416] In Math 56, CA_max represents the maximum effective diameter (mm) among the object-side surface and the sensor-side surface of the plurality of lenses, and TTL (total lens length) represents the distance on the optical axis OA from the vertex of the first surface S1 of the first lens 101 to the image surface of the image sensor 300. Math 56 establishes a relationship between the total length on the optical axis of the optical system and the maximum effective diameter, thereby providing a slim and compact optical system.

[0417] Mathematical formula 56 may further include mathematical formula 56-1. Here, nL is the number of lenses in the optical system, which may be 6 to 8, preferably 7.

[0418] [Mathematical formula 56-1] 0<(TTL / CA_max) / nL<0.2

[0419] [Mathematical formula 57]

[0420] 0.4 <TTL / (2*ImgH)<0.7

[0421] Mathematical formula 57 can set the total length TTL on the optical axis of the optical system and the diagonal length (2*ImgH) of the image sensor 300. When the optical system 1000 according to the embodiment satisfies mathematical formula 47, the optical system 1000 can have a smaller TTL by ensuring BFL (back focal length) to apply a relatively large image sensor 300, for example, a larger image sensor 300 of about 1 inch, and can have a high-definition implementation and a slim structure.

[0422] Mathematical formula 57 may also include mathematical formula 57-1. Here, nL is the number of lenses in the optical system, which may be 6 to 8, preferably 7.

[0423] [Mathematical formula 57-1] 0 < (TTL / (2 * ImgH)) / nL < 0.2

[0424] [Mathematical formula 58]

[0425] 0.01 <BFL / ImgH<0.5

[0426] Mathematical formula 58 can set the optical axis distance between the image sensor 300 and the last lens and the length of the image sensor 300 in the diagonal direction from the optical axis. When the optical system 1000 according to the embodiment satisfies mathematical formula 58, the optical system 1000 can ensure the BFL to apply a relatively large image sensor 300, for example, a larger image sensor 300 of about 1 inch, and minimize the distance between the last lens and the image sensor 300, thereby having good optical characteristics in the center and peripheral parts of the FOV.

[0427] Mathematical formula 58 may also include mathematical formula 58-1. Here, nL is the number of lenses in the optical system, which may be 6 to 8, preferably 7.

[0428] [Mathematical formula 58-1] 0 < (BFL / ImgH) / nL < 0.1

[0429] [Math 59]

[0430] 4 <TTL / BFL<10

[0431] Mathematical formula 59 can set the total optical axis length (TTL) of the optical system and the optical axis distance (BFL) between the image sensor 300 and the last lens (unit: mm). In the present invention, since the sensor side surface of the last lens has no critical point, the value of mathematical formula 59 can be 5 mm or more, or 6 mm or more. When the optical system 1000 according to the embodiment satisfies mathematical formula 59, the optical system 1000 ensures the BFL and can be set to be slim and compact.

[0432] Math 59 may further include Math 59-1. Here, nL is the number of lenses in the optical system, which may be 6 to 8, preferably 7.

[0433] [Mathematical formula 59-1] 0.3 < (TTL / BFL) / nL < 1

[0434] [Math 60]

[0435] 0.5 <F / TTL<1.2

[0436] Mathematical formula 60 can set the first and second direction average values ​​of the total focal length F and the total length TTL on the optical axis of the optical system 1000. Therefore, a slim and compact optical system can be provided.

[0437] Mathematical formula 60 may further include mathematical formula 60-1. Here, nL is the number of lenses in the optical system, which may be 6 to 8, preferably 7.

[0438] [Mathematical formula 60-1] 0<(F / TTL) / nL<0.3

[0439] [Mathematical formula 61]

[0440] 3 <F / BFL<10

[0441] Mathematical formula 61 can set the total focal length F of the optical system 1000 and the optical axis distance (BFL) between the image sensor 300 and the last lens (unit: mm). In the present invention, since there is no critical point on the sensor side surface of the last lens, the BFL value is narrow, so the value of mathematical formula 61 can be 5 mm or greater. When the optical system 1000 according to the embodiment satisfies mathematical formula 61, the optical system 1000 can have a set FOV, can have an appropriate focal length, and can provide a slim and compact optical system. In addition, the optical system 1000 can minimize the distance between the last lens and the image sensor 300, so that it can have good optical characteristics in the peripheral part of the FOV.

[0442] Mathematical formula 61 may further include mathematical formula 61-1. Here, nL is the number of lenses in the optical system, which may be 6 to 8, preferably 7.

[0443] [Mathematical formula 61-1] 0.2 < (F / TTL) / nL < 3

[0444] [Mathematical formula 62]

[0445] 0.1 <F / ImgH<3

[0446] Math 62 may set the total focal length F (mm) of the optical system 1000 and the diagonal length ImgH of the optical axis of the image sensor 300. By applying a relatively large image sensor 300, for example, a large image sensor 300 of about 1 inch, the optical system 1000 may have improved aberration characteristics.

[0447] Mathematical formula 62 may further include mathematical formula 62-1. Here, nL is the number of lenses in the optical system, which may be 6 to 8, preferably 7.

[0448] [Mathematical formula 62-1] 0 < (F / Imgh) / nL < 0.3

[0449] [Mathematical formula 63]

[0450] 1≤F / EPD<5

[0451] Equation 63 can set the overall focal length F (mm) and the entrance pupil size of the optical system 1000. Therefore, the overall brightness of the optical system can be controlled.

[0452] Mathematical formula 63 may further include mathematical formula 63-1. Here, nL is the number of lenses in the optical system, which may be 6 to 8, preferably 7.

[0453] [Mathematical formula 63-1] 0.1 < (F / EPD) / nL < 0.4

[0454] [Mathematical formula 64]

[0455] 1 <F / CA_L1S1<2

[0456] In Math 64, CA_L1S1 is an effective diameter of the object-side surface of the first lens 101. The optical system may set an average value of effective focal lengths in the first direction and the second direction and the incident-side effective diameter by Math 64.

[0457] [Mathematical formula 65]

[0458] 50 <Inf62*L6S2_Max_slope<120

[0459] Inf62 is an average value of distances from the optical axis to critical points in the first direction X and the second direction Y of the twelfth sensor-side surface S12 of the sixth lens 106, and L6S2_Max_slope is a maximum angle between the optical axis OA and a normal line perpendicular to a tangent line passing through any point on the sensor-side surface S12 of the sixth lens 106. When Mathematical Formula 65 is satisfied, good optical performance can be obtained in the peripheral portion of the image sensor 300 by adjusting the refraction angle of the sensor-side surface of the sixth lens 106 having a free-form surface. Wherein, * represents multiplication.

[0460] [Mathematical formula 66]

[0461] 30 <Inf72*L7S2_Max_slope<110

[0462] Inf72 is an average value of distances from the optical axis to critical points in the first direction X and the second direction Y of the fourteenth sensor-side surface S14 of the seventh lens 107, and L7S2_Max_slope is a maximum angle between the optical axis OA and a normal line perpendicular to a tangent line passing through any point on the fourteenth sensor-side surface S14 of the seventh lens 107. When Mathematical Formula 66 is satisfied, good optical performance can be obtained in the peripheral portion of the image sensor 300 by adjusting the refraction angle of the sensor-side surface of the seventh lens 107 having a free-form surface.

[0463] [Mathematical formula 67]

[0464] 0.7 <Inf61 / Inf62<1.2

[0465] Inf61 and Inf62 represent average values ​​of distances from the optical axis to critical points in the first direction X and the second direction Y of the object-side eleventh surface S11 and the sensor-side twelfth surface S12 of the sixth lens 106. When Math Formula 67 is satisfied, good optical performance can be obtained in the peripheral portion of the image sensor 300 by adjusting the lens surface of the sixth lens 106 having a free-form surface.

[0466] [Mathematical formula 68]

[0467] 0.2 <Inf71 / Inf72<1

[0468] Inf71 and Inf72 represent average values ​​of distances from the optical axis to critical points in the first direction X and the second direction Y of the thirteenth object-side surface S13 and the fourteenth sensor-side surface S14 of the seventh lens 107. When Mathematical Formula 68 is satisfied, good optical performance can be obtained in the peripheral portion of the image sensor 300 by adjusting the lens surface of the seventh lens 106 having a free-form surface.

[0469] [Math 69]

[0470] 45 <L6S2x_max slope<70

[0471] L6S2x_max slope is the maximum angle formed by a normal line perpendicular to a tangent line passing through an arbitrary point in the first direction X of the sensor-side twelfth surface S12 of the sixth lens 106 and the optical axis OA.

[0472] [Mathematical formula 70]

[0473] 45 <L6S2y_max slope<70

[0474] L6S2y_max slope is a maximum angle formed by a normal line perpendicular to a tangent line at any point in the second direction Y passing through the sensor-side twelfth surface S12 of the sixth lens 106 and the optical axis OA. The value of L6S2y_max slope and the value of L6S2y_max slope may be different from each other.

[0475] [Mathematical formula 71]

[0476] 0.5 <CA_L6S2x / CA_L6S2y<1

[0477] CA_L6S2x is an effective diameter of the sensor-side twelfth surface S12 of the sixth lens 106 in the first direction X, and CA_L6S2y is an effective diameter of the sensor-side twelfth surface S12 of the sixth lens 106 in the second direction Y. According to Mathematical Formula 71,

[0478] The effective diameter of the sensor-side surface of the sixth lens 106 having a free-form surface may be different in the first direction orthogonal to the optical axis, the second direction, and the axial direction therebetween (30 degrees, 45 degrees, 53 degrees, 60 degrees, etc.).

[0479] [Mathematical formula 72]

[0480] 45<|L7S2x_max slope|<70

[0481] L7S2x_max slope is the maximum angle formed by a normal line perpendicular to a tangent line passing through an arbitrary point in the first direction X of the sensor-side fourteenth surface S14 of the seventh lens 107 and the optical axis OA.

[0482] [Mathematical formula 73]

[0483] 45<|L7S2y_max slope|<70

[0484] L7S2y_maxslope is a maximum angle formed by a normal line perpendicular to a tangent line at any point in the second direction Y passing through the sensor-side fourteenth surface S14 of the seventh lens 107, and the optical axis OA. The value of L7S2y_maxslope and the value of L7S2y_maxslope may be different from each other.

[0485] [Mathematical formula 74]

[0486] 1 <CA_L7S2x / CA_L7S2y<1.2

[0487] CA_L7S2x is an effective diameter of the sensor-side fourteenth surface S14 of the seventh lens 107 in the first direction X, and CA_L7S2y is an effective diameter of the sensor-side fourteenth surface S14 of the seventh lens 107 in the second direction Y. According to Mathematical Formula 75, the effective diameter of the sensor-side surface of the seventh lens 107 having a free-form surface may be different in the first direction and the second direction orthogonal to the optical axis and in the axial direction therebetween (30 degrees, 45 degrees, 53 degrees, 60 degrees, etc.).

[0488] [Mathematical formula 75]

[0489] 1 <D34_CT / D34_ET<8

[0490] D34_CT is the center distance between the third lens 103 and the fourth lens 104, and D34_ET is the distance between the third lens 103 and the fourth lens 104 at the end of the effective area. That is, D34_ET is the optical axis distance between the end of the effective area of ​​the sensor-side surface of the third lens 103 and the end of the effective area of ​​the object-side surface of the fourth lens 104. When Math Formula 75 is satisfied, the optical system can improve chromatic aberration by reducing chromatic aberration.

[0491] [Mathematical formula 76]

[0492] 1 <D56_CT / D56_ET<3

[0493] D56_CT is the distance between the centers of the fifth lens 105 and the sixth lens 106, and D56_ET is the distance between the fifth lens 105 and the sixth lens 106 at the end of the effective area. That is, D56_ET is the optical axis distance between the end of the effective area of ​​the sensor-side surface of the fifth lens 105 and the end of the effective area of ​​the object-side surface of the sixth lens 106. When Math Formula 76 is satisfied, the optical system can improve distortion and chromatic aberration at the peripheral portion of the FOV.

[0494] [Mathematical formula 77]

[0495] 0 <D67_max / D67_CT<2

[0496] D67_Max is the maximum distance between the sixth lens 106 and the seventh lens 107, and D67_CT is the center distance between the sixth lens 106 and the seventh lens 107. When Math Formula 77 is satisfied, the optical system can improve distortion and chromatic aberration at the peripheral portion of the FOV by adjusting the distance between the last two lenses.

[0497] [Mathematical formula 78]

[0498] 0.01 <D12_CT / D67_CT<1

[0499] D12_CT is the center distance between the first lens 101 and the second lens 102. When Math Formula 78 is satisfied, aberration characteristics of the optical system can be improved and a slim optical system can be designed.

[0500] [Mathematical formula 79]

[0501] 1 <D67_CT / D67_Min<10

[0502] D67_Min represents a minimum distance among distances between the sixth lens 106 and the seventh lens 107. When Math Formula 79 is satisfied, the optical system can reduce the influence of distortion aberration and improve peripheral image quality.

[0503] [Math 80]

[0504] 0 <L7_ET / L7_CT<1.2

[0505] L7_ET is the thickness of the seventh lens 107 at the end of the effective area in the optical axis direction. When Mathematical Formula 80 is satisfied, the influence of distortion aberration can be reduced. The thickness at the end of the effective area in the optical axis direction is the optical axis distance between the end of the effective area of ​​the object side surface of each lens and the end of the effective area of ​​the sensor side surface of each lens.

[0506] [Mathematical formula 81]

[0507] 0.5 <L3_CT / L3_ET<2

[0508] L3_ET is the thickness of the third lens 103 at the end of the effective area along the optical axis direction. When Math. 81 is satisfied, the influence of chromatic aberration can be reduced.

[0509] [Mathematical formula 82]

[0510] 1 <D67_CT / D67_ET<5

[0511] D67_CT and D67_ET represent the distance between the center and the end of the effective area in the distance between the sixth lens 106 and the seventh lens 107. When Math Formula 82 is satisfied, the optical system can improve distortion and chromatic aberration at the peripheral portion of the FOV by adjusting the distance between the last two lenses.

[0512] [Mathematical formula 83]

[0513]

[0514] In mathematical formula 83, Z is the Sag value, which can represent the distance from any position on the aspheric surface to the vertex of the aspheric surface in the direction of the optical axis. Y can represent the distance from any position on the aspheric surface to the optical axis in a direction perpendicular to the optical axis. c can represent the curvature of the lens, and K can represent the cone constant. In addition, A, B, C, D, E and F can represent aspheric constants. In the practice of the present invention, an aspheric surface can be provided from the first surface S1 (i.e., L1S1) to the tenth surface S10 (i.e., L5S2).

[0515] [Mathematical formula 84]

[0516]

[0517] Mathematical formula 84 is a coefficient of the free-form surfaces of the object-side surface and the sensor-side surface of the sixth lens 106 and the seventh lens 107, and can be expressed as follows Figure 7 and Fig.13 The 80th order coefficients are shown as the SPS Q2D surface equation. Here, the variables with a tilde (~) represent parameters in the off-axis coordinate system.

[0518] The optical system 1000 according to the embodiment may satisfy at least one or two or more of mathematical formulas 1 to 82. In this case, the optical system 1000 may have improved optical characteristics. In detail, when the optical system 1000 satisfies at least one or two or more of mathematical formulas 1 to 82, the optical system 1000 has improved resolution, and aberration and distortion characteristics may be improved. In addition, the optical system 1000 may ensure BFL (back focal length) to apply a large-size image sensor 300, and may minimize the distance between the last lens and the image sensor 300, so that it may have good optical performance in the center and peripheral parts of the FOV. In addition, when the optical system 1000 satisfies at least one of mathematical formulas 1 to 70, it may include a relatively large image sensor 300, have a relatively small TTL value, and be thinner. A compact optical system and a camera module having the optical system may be provided.

[0519] In the optical system 1000 according to the embodiment, the distance between the plurality of lenses 100 may have a value set according to a region.

[0520] Figure 5 Is based on having Figure 1 An example of lens data of the first embodiment of the optical system, Fig.11 Is based on having Figure 1 An example of lens data of the second embodiment of the optical system.

[0521] like Figure 5 and Fig.11As shown, the optical system according to the first embodiment and the second embodiment represents the radius of curvature of the first lens to the seventh lens 101 to 107, the thickness of each lens, the distance between the lenses on the optical axis OA, the refractive index at the d line (588nm), the Abbe number, and the size of the effective diameter CA (clear aperture). The F number in the present invention may be different from each other in the first direction and the second direction, and may be 1.5 or more, for example, in the range of 1.5 to 2.5. At least one or both of the object side surface and the sensor side surface of the sixth lens 106 may be provided with a free surface, and at least one or both of the object side surface and the sensor side surface of the seventh lens 107 may be provided with a free surface. A curved surface may be provided. Therefore, the optical performance of the peripheral part of the FOV may be satisfactorily corrected.

[0522] Table 1 relates to the terms of the above mathematical formula in the optical system 1000 according to the first to third embodiments, including the TTL (total lens length), BFL (back focal length), total effective focal length, distance F value, ImgH, the focal length of each of the first to seventh lenses (F1, F2, F3, F4, F5, F6, F7), the composite focal length, etc. of the optical system 1000.

[0523]

Table 1

[0524]

[0525]

[0526] Table 2 shows the Figure 1 Table of edge distances AIR_ET (mm) and edge thicknesses ET (mm) of the first to seventh lenses L1 to L7 of the first and second embodiments of the optical system 1000.

[0527]

Table 2

[0528]

[0529]

[0530] Table 3 shows Figure 1 Result values ​​of Mathematical Formulas 1 to 55 in the optical system 1000. Referring to Table 3, it can be seen that the optical system 1000 satisfies at least one, two or more, or three or more of Mathematical Formulas 1 to 55. In detail, it can be seen that the optical system 1000 according to the embodiment satisfies all of the above Mathematical Formulas 1 to 55. Therefore, the optical system 1000 can improve the optical performance and optical characteristics at the center and peripheral parts of the FOV.

[0531]

Table 3

[0532]

[0533]

[0534]

[0535]

[0536] Table 4 shows Figure 1 Result values ​​of mathematical formulas 56 to 82 in the optical system 1000. Referring to Table 4, it can be seen that the optical system 1000 satisfies at least one, two or more, or three or more of mathematical formulas 56 to 82. In detail, it can be seen that the optical system 1000 according to the embodiment satisfies all of the above-mentioned mathematical formulas 56 to 82. In addition, at least one of mathematical formulas 56 to 82 can satisfy at least one or two or more of mathematical formulas 1 to 55. Therefore, the optical system 1000 can improve the optical performance and optical characteristics at the center and peripheral parts of the FOV.

[0537]

Table 4

[0538]

[0539]

[0540] Fig.19 is a diagram showing that a camera module according to an embodiment is applied to a mobile terminal.

[0541] refer to Fig.19 , the mobile terminal 1 may include a camera module 10 disposed at the rear side. The camera module 10 may include an image capture function. In addition, the camera module 10 may include at least one of an auto focus function, a zoom function, and an OIS function.

[0542] 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 can be stored in a memory (not shown). In addition, although not shown in the figure, the camera module can also be set on the front side of the mobile terminal 1.

[0543] For example, the camera module 10 may include a first camera module 10A and a second camera module 10B. At this time, at least one of the first camera module 10A and the second camera module 10B may include the above-mentioned optical system 1000. Therefore, the camera module 10 may have a slim structure and may have improved distortion and aberration characteristics. In addition, the camera module 10 may have good optical performance even in the center and peripheral parts of the FOV.

[0544] In addition, the mobile terminal 1 may further include an autofocus device 31. The autofocus device 31 may include an autofocus function using a laser. The autofocus device 31 may be mainly used under conditions where the autofocus function of the image using the camera module 10 is degraded, such as a distance of 10 m or less or a dark environment. The autofocus device 31 may include a light emitting unit including a vertical cavity surface emitting laser (VCSEL) semiconductor device, and a light receiving unit that converts light energy into electrical energy, such as a photodiode.

[0545] In addition, the mobile terminal 1 may further include a flash module 33. The flash module 33 may include a light emitting element that emits light therein. The flash module 33 may be operated by a camera operation of the mobile terminal or a user's control.

[0546] The features, structures, effects, etc. described in the above embodiments are all included in at least one embodiment of the present invention, and are not necessarily limited to one embodiment. In addition, the features, structures, effects described in each embodiment can be combined or modified by a person skilled in the art of the embodiment relative to other embodiments. Therefore, the contents related to these combinations and modifications should be understood to be included in the scope of the present invention.

[0547] In addition, although described based on the embodiment, this is only an example, and the present invention is not limited thereto. It will be clear to those skilled in the art that various modifications and applications not described above can be made without departing from the essential features of the present embodiment. For example, each component specifically shown in the embodiment can be modified and implemented. Moreover, the differences associated with these modifications and applications should be understood to be included within the scope of the present invention defined in the appended claims.

Claims

1. An optical system, comprising: The first lens to the seventh lens are arranged along the optical axis from the object side to the sensor side. Wherein, the object side surface of the first lens is convex, wherein at least one of the object-side surface and the sensor-side surface of the sixth lens has at least one critical point, wherein each of the object-side surface and the sensor-side surface of the seventh lens has a critical point, wherein at least one of the object-side surface and the sensor-side surface of the seventh lens has a free-form surface shape in which a lens surface orthogonal to the optical axis in a first direction and a lens surface orthogonal to the optical axis in a second direction are asymmetric, and The free-form surface has lens surfaces symmetrical about the optical axis on both sides of the first direction, and lens surfaces symmetrical about the optical axis on both sides of the second direction.

2. The optical system according to claim 1, in, Each of the object-side surface and the sensor-side surface of the sixth lens has a critical point, The critical point of the object-side surface of the seventh lens is positioned closer to the optical axis than the critical points of the object-side surface and the sensor-side surface of the sixth lens.

3. The optical system according to claim 1, in, The sixth lens includes regions having different thicknesses at the same radial position in the first direction and the second direction orthogonal to the optical axis.

4. The optical system according to claim 1, in, The seventh lens includes regions having different thicknesses at the same radial position in the first direction and the second direction relative to the optical axis.

5. The optical system according to claim 3 or 4, in, The sixth lens includes regions having different thicknesses within the same radius in different axial directions between the first direction and the second direction orthogonal to the optical axis.

6. The optical system according to claim 5, in, The seventh lens includes regions having different thicknesses within the same radius in different axial directions between the first direction and the second direction orthogonal to the optical axis.

7. An optical system according to any one of claims 1 to 4, in, The maximum angle between a normal line perpendicular to a tangent line passing through a sensor-side surface of the sixth lens and the optical axis has different angles in the first direction and the second direction orthogonal to the optical axis.

8. An optical system according to any one of claims 1 to 4, in, The maximum angle between a normal line perpendicular to a tangent line passing through a sensor-side surface of the seventh lens and the optical axis has different angles in the first direction and the second direction orthogonal to the optical axis.

9. The optical system according to any one of claims 1 to 4, in, The first lens has positive refractive power and has a meniscus shape convex toward the object side on the optical axis, The second lens and the third lens have opposite refractive powers to each other, and each of the second lens and the third lens has a meniscus shape convex toward the object side on the optical axis.

10. The optical system according to any one of claims 1 to 4, in, The fourth lens has positive refractive power. Among them, the fifth lens has negative refractive power. The sum of the center thicknesses of the fourth lens and the fifth lens is smaller than the center distance between the second lens and the third lens.

11. An optical system according to any one of claims 1 to 4, in, The sixth lens has positive refractive power, an object-side surface of the sixth lens has a convex shape on the optical axis, and a sensor-side surface of the sixth lens has a concave shape on the optical axis, The seventh lens has negative refractive power, an object-side surface of the seventh lens has a convex shape on the optical axis, and a sensor-side surface of the seventh lens has a concave shape on the optical axis.

12. An optical system comprising: The first lens to the seventh lens are arranged along the optical axis from the object side to the sensor side. wherein the first lens has a convex object-side surface, wherein at least one of the object-side surface and the sensor-side surface of the sixth lens has a free-form surface, wherein each of the object-side surface and the sensor-side surface of the seventh lens has a critical point, At least one of the object-side surface and the sensor-side surface of the seventh lens has a free-form surface shape, in which a lens surface orthogonal to the optical axis in a first direction is asymmetric to a lens surface orthogonal to the optical axis in a second direction, and satisfies the following mathematical formula: Mathematical formula: 0≤|EFLX-EFLY|≤0.1, Wherein, EFLX is the effective focal length in the first direction, and EFLY is the effective focal length in the second direction.

13. The optical system according to claim 12, in, The sensor side surface of the sixth lens is a free-form surface with a critical point and satisfies the following mathematical formula: Math formula: 50 <Inf62*L6S2_Max_slope<120, Wherein, Inf62 is the average value of the critical points of the sensor side surface of the sixth lens in the first direction and the second direction, and L6S2_Max_slope is the maximum angle between the optical axis and the normal to the tangent line passing through any point on the sensor side surface of the sixth lens.

14. The optical system according to claim 12, in, The sensor side surface of the seventh lens is a free-form surface with a critical point. Math formula: 30 <Inf72*L7S2_Max_slope<110, Wherein, Inf72 is the average value of the critical points of the sensor side surface of the seventh lens in the first direction and the second direction, and L7S2_Max_slope is the maximum angle between the optical axis and the normal to the tangent line passing through any point on the sensor side surface of the seventh lens.

15. An optical system according to any one of claims 12 to 14, in, EFLX and EFLY have different values.

16. An optical system according to any one of claims 12 to 14, in, The sensor-side surface of the seventh lens has a free-form surface, The distance from the optical axis to the critical point in the first direction of the sensor-side surface of the seventh lens is different from the distance from the optical axis to the critical point in the second direction.

17. The optical system according to claim 16, in, The center distance between the sixth lens and the seventh lens is the maximum value of the center distances between the first lens and the seventh lens. The center thickness of the second lens is the maximum value among the center thicknesses of the first lens to the seventh lens.

18. An optical system according to any one of claims 1 to 5, in, An average distance of the object-side surface of the seventh lens from the optical axis to critical points in the first direction and the second direction is Inf71, an average distance of the sensor-side surface of the seventh lens from the optical axis to critical points in the first direction and the second direction is Inf72, and the following mathematical formula is satisfied: Mathematical formula: 0.2 <Inf71 / Inf72<1 Among them, Inf71 and Inf72 are different from each other, Among them, the following mathematical formula is satisfied: Mathematical formula: 0.4 <TTL / (Imgh*2)<0.7 (TTL is the distance on the optical axis from the vertex of the object-side surface of the first lens to the image surface of the image sensor, and ImgH is 1 / 2 of the maximum diagonal length of the image sensor).

19. An optical system comprising: A first lens group on the object side having three or fewer lenses; as well as a second lens group on the sensor side of the first lens group having four or fewer lenses, Wherein, the first lens group has positive (+) refractive power on the optical axis, Wherein, the second lens group has negative (-) refractive power on the optical axis, The number of lenses in the second lens group is less than twice the number of lenses in the first lens group. Among them, on the lens surfaces of the first lens group and the second lens group, the lens closest to the second lens group has the smallest effective diameter, The last lens closest to the image sensor in the lens surfaces of the first lens group and the second lens group has the largest effective diameter, wherein a sensor-side surface of the first lens group closest to the second lens group has a concave shape, wherein the object-side surface of the second lens group closest to the first lens group has a concave shape, The sensor side surface of the last lens in the first lens group and the second lens group closest to the image sensor has a free-form surface shape, and the free-form surface shape has a critical point. wherein a sensor side surface closest to the image sensor has a free-form surface in which a lens surface orthogonal to the optical axis in a first direction and a lens surface orthogonal to the optical axis in a second direction are asymmetric, and The free-form surface has lens surfaces that are symmetrical on both sides of the optical axis in a first direction, and has lens surfaces that are symmetrical on both sides of the optical axis in a second direction.

20. The optical system according to claim 19, in, A focal length of the second lens group in the first direction and a focal length of the second lens group in the second direction are different from each other.

21. An optical system according to claim 19 or 20, in, The optical system satisfies the following mathematical formula: Mathematical formula: 0.4 <TTL / (Imgh*2)<0.7 (TTL is the distance on the optical axis from the vertex of the object-side surface of the first lens to the image surface of the image sensor, and ImgH is 1 / 2 of the maximum diagonal length of the image sensor).

22. The optical system according to claim 11 or 12, in, The first lens group includes first to third lenses arranged along the optical axis from the object side toward the sensor side, The second lens group includes fourth to seventh lenses arranged along the optical axis from the object side toward the sensor side, wherein each of the object-side surface and the sensor-side surface of the sixth lens is a free-form surface shape having a critical point, The object-side surface of the seventh lens has a free-form surface shape, and the free-form surface shape has a critical point.

23. A camera module, comprising: Image sensor; as well as a filter disposed between the image sensor and the last lens of the optical system, wherein the optical system comprises an optical system according to any one of claims 1, 12 or 19, Wherein, the camera module satisfies the following mathematical formula: Mathematical formula: 0.5 <F / TTL<1.2 Mathematical formula: 0<(F / TTL) / nL<0.3 (F is the average value of the total focal length of the optical system in two directions orthogonal to the optical axis, the total lens length TTL is the distance from the vertex of the object side surface of the first lens to the image surface of the image sensor on the optical axis, and nL is the total number of lenses).

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