Optical system and camera module including the same

Abstract

An optical system disclosed in an embodiment of the present invention includes first to eighth lenses disposed along an optical axis in a direction from an object side to a sensor side, wherein: the first lens has a positive (+) refractive power on the optical axis and has a meniscus shape protruding toward the object side; an eighth lens having negative (-) refractive power on the optical axis and having a meniscus shape protruding toward the object side; an object-side surface of the seventh lens has a critical point; a sensor-side surface of the third lens has a critical point, and a sensor-side surface of the eighth lens has a critical point, and when an effective diameter of a sensor-side surface of the third lens is CAL3S2, an effective diameter of an object-side surface of the fourth lens is CAL4S1, a maximum thickness among center thicknesses of the first to eighth lenses is CTMax, a maximum gap among gaps between the first to eighth lenses is CGMax, and the effective diameter of the sensor-side surface of the third lens is CAL3S2. The following mathematical relationship is satisfied: 0.5 lt; cAL3S2 / CAL4S1lt, and CAL4S1lt; 1.5 and 0 lt; cTMaxt / CGMaxt, and CTMaxt / 1.

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

[0007]

Technical issues

[0008] Embodiments of the present invention provide an optical system with improved optical characteristics. Embodiments provide an optical system having excellent optical performance in the central and peripheral portions of the field of view. Embodiments provide an optical system capable of having a thin structure.

[0009]

Technical Solution

[0010] The optical system according to an embodiment of the present invention includes a first lens to an eighth lens, which are arranged along the optical axis in the direction from the object side to the sensor side. Among them, the first lens has a positive (+) refractive power on the optical axis and has a meniscus shape convex toward the object side, the eighth lens has a negative (-) refractive power on the optical axis and has a meniscus shape convex toward the object side, the object-side surface of the seventh lens has a critical point, the sensor-side surface of the eighth lens has a critical point, the effective diameter of the sensor-side surface of the third lens is CA_L3S2, the effective diameter of the object-side surface of the fourth lens is CA_L4S1, the maximum thickness among the central thicknesses of the first lens to the eighth lens is CT_Max, the maximum distance among the distances between the first lens to the eighth lens is CG_Max, and the following mathematical formula (equation) can be satisfied: 0.5 < CA_L3S2 / CA_L4S1 < 1.5 and 0 < CT_Max / CG_Max < 1.

[0011] According to an embodiment of the present invention, each of the sensor-side surface of the seventh lens and the object-side surface of the eighth lens has a critical point, and the critical point of the object-side surface of the eighth lens can be closer to the optical axis than the critical points of the object-side surface and the sensor-side surface of the seventh lens.

[0012] According to an embodiment of the present invention, the optical axis distance from the center of the object-side surface of the first lens to the surface of the image sensor is TTL, half of the maximum diagonal length of the image sensor is Imgh, the field of view of the optical system is FOV, and the following mathematical formula can be satisfied: 5 < (TTL / Imgh) * n < 15 and (TTL * n) < FOV, where n can be the total number of lenses.

[0013] According to an embodiment of the present invention, when the entrance pupil diameter of the optical system is EPD, and the radius of curvature of the object-side surface of the first lens on the optical axis is L1R1, the following mathematical formula can be satisfied: 1 < EPD / L1R1 < 2.

[0014] According to an embodiment of the present invention, the following mathematical formula can be satisfied: Imgh < TTL and 50 < TTL * Imgh < 90 (the optical axis distance from the center of the object-side surface of the first lens to the surface of the image sensor is TTL, and half of the maximum diagonal length of the image sensor is Imgh).

[0015] According to an embodiment of the present invention, a normal line perpendicular to a tangent line passing through an arbitrary point on the sensor-side surface of the eighth lens has a maximum first angle with respect to the optical axis, and the first angle may be satisfied within a range of 20 to 40 degrees.

[0016] According to an embodiment of the present invention, a normal line perpendicular to a tangent line passing through any point on the object-side surface of the eighth lens has a maximum second angle with respect to the optical axis, and a difference between the first angle and the second angle may be less than 10 degrees.

[0017] According to an embodiment of the present invention, a normal line perpendicular to a tangent line passing through any point on the sensor-side surface of the seventh lens has a maximum third angle with respect to the optical axis, and a difference between the first angle and the third angle may be less than 10 degrees.

[0018] According to an embodiment of the present invention, a normal line perpendicular to a tangent line passing through any point on the object-side surface of the seventh lens has a maximum fourth angle with respect to the optical axis, and a difference between the first angle and the fourth angle may be less than 10 degrees.

[0019] According to an embodiment of the present invention, the second lens, the third lens, and the seventh lens may have a meniscus shape that is convex toward the object side on the optical axis.

[0020] According to an embodiment of the present invention, the maximum value of the effective diameter of the object side surface and the sensor side surface of each of the first to eighth lenses is CA_Max, 1 / 2 of the maximum diagonal length of the image sensor is Imgh, and the following mathematical formula can be satisfied: 0.1 <CA_max / (2*ImgH)<1。

[0021] According to an embodiment of the present invention, the following mathematical formula can be satisfied: (v3*n3)<(v1*n1) (v1 is the Abbe number of the first lens, v3 is the Abbe number of the third lens, n1 is the refractive index of the first lens, and n3 is the refractive index of the third lens).

[0022] An optical system according to an embodiment of the present invention includes: a first lens group disposed on the object side, which has a plurality of lenses; a second lens group disposed on the sensor side of the first lens group, which has a plurality of lenses; and an aperture stop, which is disposed around the object-side surface of any one lens of the first lens group. Wherein, each lens of the first lens group has a meniscus shape convex toward the object side on the optical axis, the last nth lens and the (n - 1)th lens among the lenses of the second lens group have a meniscus shape convex toward the object side on the optical axis, the first lens group has a positive refractive power, the second lens group has a negative refractive power, the number of lenses in the second lens group is greater than the number of lenses in the first lens group, and the following mathematical formula can be satisfied: 40 < (FOV * TTL) / n < 150 (TTL is the optical axis distance from the center of the object-side surface of the first lens to the surface of the image sensor, n is the total number of lenses, and FOV is the field of view).

[0023] According to an embodiment of the present invention, the effective diameter of the lenses of the first lens group gradually decreases from the object side toward the sensor side, while the effective diameter of the lenses of the second lens group can gradually increase from the lens surface closest to the first lens group toward the image sensor.

[0024] According to an embodiment of the present invention, the focal length of the first lens group is F13, the focal length of the second lens group is F48, and the following mathematical formula can be satisfied: 1 < |F48 / F13| < 4 (F48 < 0).

[0025] According to an embodiment of the present invention, the first lens group includes a first lens to a third lens, the second lens group includes a fourth lens to an eighth lens, and the aperture stop is disposed around the object-side surface of the second lens, and the following mathematical formula can be satisfied: CT6 + CT7 + CT8 < CG7 (CT6 is the central thickness of the sixth lens, CT7 is the central thickness of the seventh lens, CT8 is the central thickness of the eighth lens, and CG7 is the central distance between the seventh lens and the eighth lens).

[0026] According to an embodiment of the present invention, the object-side surface and the sensor-side surface of the seventh lens may have critical points, and the object-side surface and the sensor-side surface of the eighth lens may have critical points.

[0027] According to an embodiment of the present invention, the difference between the angle between the optical axis and the normal line perpendicular to the tangent line at any point on the object-side surface of the seventh lens and the angle between the optical axis and the normal line perpendicular to the tangent line at any point on the object-side surface of the eighth lens may be less than 10 degrees.

[0028] According to an embodiment of the present invention, the difference between the angle between the optical axis and the normal line perpendicular to the tangent line at any point on the sensor-side surface of the seventh lens and the angle between the optical axis and the normal line perpendicular to the tangent line at any point on the sensor-side surface of the eighth lens may be less than 10 degrees.

[0029] According to an embodiment of the present invention, the following mathematical formula can be satisfied: 100 < |L5R2 / CT5| < 300 (where L5R2 is the radius of curvature of the fifth lens on the optical axis, and CT5 is the central thickness of the fifth lens).

[0030] According to an embodiment of the present invention, the following mathematical formulas can be satisfied: 0 < CT6 / CG7 < 2, 2 < CG6 / CT6 < 9, and 1 < CG7 / CT7 < 5 (where CT6 is the central thickness of the sixth lens, CT7 is the central thickness of the seventh lens, CG6 is the central distance between the sixth lens and the seventh lens, and CG7 is the central distance between the seventh lens and the eighth lens).

[0031] According to an embodiment of the present invention, the sum of the central thicknesses ∑CT of the lenses in the first lens group and the second lens group and the sum of the distances ∑CG between two adjacent lenses can satisfy the following mathematical formula: 0 < ∑CT / ∑CG < 1.

[0032] A camera module according to an embodiment of the present invention includes: an image sensor disposed on the sensor side of a plurality of lenses; and an optical filter disposed between the image sensor and the last lens, wherein the optical system includes the optical system disclosed above and can satisfy the following mathematical formulas: 0.5 < F / TTL < 1.5, 0.5 < TTL / ImgH < 3, and 4 ≤ Imgh < TTL (where F is the total focal length, TTL is the distance on the optical axis from the center of the object-side surface of the lens closest to the object side to the image surface of the image sensor, and Imgh is 1 / 2 of the maximum diagonal length of the image sensor).

[0033]

Beneficial Effects

[0034] The optical system and the camera module according to the embodiment can have improved optical characteristics. Specifically, according to the surface shape, refractive power, thicknesses of a plurality of lenses, and distances between adjacent lenses among the plurality of lenses, the optical system can have improved aberration characteristics and resolution.

[0035] The optical system and the camera module according to the embodiment can have improved distortion and aberration characteristics and can have good optical performance at the center and peripheral portions of the field of view (FOV).

[0036] The optical system according to the embodiment can have improved optical characteristics and a smaller total lens length (TTL), and thus can provide an optical system and a camera module including the optical system in a thin and compact structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a configuration diagram of an optical system and a camera module according to an embodiment of the present invention.

[0038] 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.

[0039] Figure 3 It is shown that according to Figure 1 A table of lens data for examples of optical systems.

[0040] Figure 4 ] is an example of the aspherical coefficient of the lens according to the embodiment of the present invention.

[0041] Figure 5 : is a table showing lens thicknesses and intervals between lenses according to a direction orthogonal to the optical axis in an optical system according to an embodiment of the present invention.

[0042] Figure 6 : is a table showing Sag values ​​of the object-side surface and the sensor-side surface of the seventh lens and the eighth lens according to the embodiment of the present invention.

[0043] Figure 7 is a graph of the diffraction MTF of the optical system according to the embodiment of the present invention.

[0044] Figure 8 : is a graph showing aberration characteristics of an optical system according to an embodiment of the present invention.

[0045] Fig. 9 : is a graph showing a curve connecting points passing through the end portions of the effective area of ​​the lens according to the embodiment of the present invention as a two-dimensional function.

[0046] Fig.10 : is a graph showing a straight line connecting points passing from the n-4th lens to the end of the effective area of ​​the nth lens according to the embodiment of the present invention as a one-dimensional function.

[0047] Fig.11 : is a graph showing Sag values ​​of the object-side surface and the sensor-side surface of the nth lens and the (n-1)th lens according to the embodiment of the present invention.

[0048] Fig.12 is a diagram showing that a camera module according to an embodiment is applied to a mobile terminal. DETAILED DESCRIPTION

[0049] 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.

[0050] 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 by 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 (upper)" or "below (lower)" of each component, the description includes not only the situation that the 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.

[0051] 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.

[0052] Figure 1 is a diagram illustrating an optical system 1000 and a camera module having the optical system 1000 according to an embodiment of the present invention.

[0053] refer to Figure 1 , the optical system 1000 or the camera module may include a plurality of lens groups LG1 and LG2. In detail, each of the plurality of lens groups LG1 and LG2 includes at least one lens. For example, the optical system 1000 may include a first lens group LG1 and a second lens group LG2 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 LG2 may be greater than the number of lenses of the first lens group LG1, for example, 1.5 times or more and 2 times or less of the number of lenses of the first lens group LG1.

[0054] The first lens group LG1 may include two or more lenses, or four or less lenses. The first lens group LG1 may be, for example, three lenses. The second lens group LG2 may include four or more lenses. The second lens group LG2 may include more lenses than the first lens group LG1, for example, six or less lenses. The number of lenses of the second lens group LG2 may be four or more, more than the number of lenses of the first lens group LG1, and may include, for example, five lenses. The optical system 1000 may include ten or less lenses, or nine or less lenses.

[0055] 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 69% or 50% to 65%. TTL is the distance from the object side surface of the lens closest to the object side on the optical axis OA to the surface of the image sensor 300, the diagonal length of the image sensor 300 is the maximum diagonal length of the image sensor 300, and can be twice the distance Imgh from the optical axis OA to the diagonal end. 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 LG1 and the second lens group LG2 is 7 to 9.

[0056] The first lens group LG1 may have a positive (+) refractive power. The second lens group LG2 may have a negative (-) refractive power different from that of the first lens group LG1. The first lens group LG1 and the second lens group LG2 have different focal lengths and different refractive powers, and thus may have good optical performance in the central portion and the peripheral portion of the FOV. The refractive power is the reciprocal of the focal length.

[0057] The first lens group LG1 may be stacked in a meniscus shape convex toward the object side. The second lens group LG2 may have a meniscus shape in which the first lens on the object side convexes toward the sensor side. The first lens group LG1 refracts light incident through the object side to converge it, and the second lens group LG2 converts light emitted through the first lens group LG1 to diffuse it to the periphery of the image sensor 300. Therefore, the two lens surfaces facing each other in the first lens group LG1 and the second lens group LG2, for example, the sensor side surface of the first lens group LG1 is concave on the optical axis, and the object side surface of the second lens group LG2 may be concave on the optical axis. In addition, the two lenses facing each other in the first lens group LG1 and the second lens group LG2 may have opposite refractive powers to each other.

[0058] When expressed in absolute values, the focal length of the second lens group LG2 may be greater than the focal length of the first lens group LG1. For example, the absolute value of the focal length F_LG2 of the second lens group LG2 may be 1.5 times or more of the absolute value of the focal length F_LG1 of the first lens group LG1, for example, in the range of 1.5 times to 3.5 times. Therefore, the optical system 1000 according to the embodiment may have improved aberration control characteristics, for example, chromatic aberration and distortion aberration, by controlling the refractive power and focal length of each lens group, and has good optical performance in the center and peripheral portions of the FOV.

[0059] On the optical axis OA, the first lens group LG1 and the second lens group LG2 may have a set distance. The optical axis distance between the first lens group LG1 and the second lens group LG2 on the optical axis OA is the separation distance on the optical axis OA, and may be the optical axis distance between the sensor side surface of the lens closest to the sensor side among the lenses of the first lens group LG1 and the object side surface of the lens closest to the object side among the lenses of the second lens group LG2. The optical axis distance between the first lens group LG1 and the second lens group LG2 may be greater than the center thickness of the last lens of the first lens group LG1, and greater than the center thickness of the first lens of the second lens group LG2. The optical axis distance between the first lens group LG1 and the second lens group LG2 may be 26% or more of the optical axis distance of the first lens group LG1, for example, in the range of 26% to 36% of the optical axis distance of the first lens group LG1. Here, the optical axis distance of the first lens group LG1 is the distance on the optical axis 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 first lens group LG1.

[0060] The optical axis distance between the first lens group LG1 and the second lens group LG2 may be 15% or less of the optical axis distance of the second lens group LG2, for example, in the range of 5% to 15% or 6% to 13%. The optical axis distance of the second lens group LG2 is the distance on the optical axis between the object side surface of the lens closest to the object side in the second lens group LG2 and the sensor side surface of the lens closest to the sensor side.

[0061] The lens with the smallest effective diameter in the first lens group LG1 may be the lens closest to the second lens group LG2. The lens with the smallest effective diameter in the second lens group LG2 may be the lens closest to the first lens group LG1. Here, the size of the effective diameter is the average of the effective diameter of the object side surface and the effective diameter of the sensor side surface of each lens. Therefore, the optical system 1000 may have good optical performance not only in the central part of the FOV but also in the peripheral part, and may improve chromatic aberration and distortion aberration. The size of the lens with the smallest effective diameter in the first lens group LG1 may be smaller than the size of the lens with the smallest effective diameter in the second lens group LG2.

[0062] The difference between the effective diameters of the lenses having the smallest effective diameters in the first lens group LG1 and the second lens group LG2 may be 0.2 mm or less. Therefore, the incident light may be refracted to the effective area between the first lens group LG1 and the second lens group LG2, and then refracted to the peripheral portion of the image sensor 300.

[0063] Among the lenses of the first lens group LG1, the lens closest to the object side has a positive (+) refractive power, and among the lenses of the second lens group LG2, the lens closest to the sensor side may have a negative (-) refractive power. In the optical system 1000, the number of lenses having a positive (+) refractive power may be equal to the number of lenses having a negative (-) refractive power. In the second lens group LG2, the number of lenses having a positive (+) refractive power may be less than the number of lenses having a negative (-) refractive power. Two lenses facing each other in the region between the first lens group LG1 and the second lens group LG2 may have different refractive powers.

[0064] Each of the plurality of lenses may include an effective area and an ineffective area. The effective area may be an area through which light incident on each lens passes. That is, the effective area may be an effective area or an effective diameter area in which optical properties are realized by refracting incident light. The ineffective area may be arranged around the effective area. The ineffective area may be an area in which effective light from a plurality of lenses is not incident. That is, the ineffective area may be an area that is not related to optical properties. In addition, the end of the ineffective area may be an area fixed to a lens barrel (not shown) that houses the lens.

[0065] 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 passes through a plurality of lenses 100 in sequence. 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). The diagonal length of the image sensor 300 may be greater than 8 mm, for example, greater than 8 mm and less than 30 mm. Preferably, the Imgh of the image sensor 300 may be less than TTL.

[0066] The optical system 1000 may include an optical filter 500. The optical filter 500 may be disposed between the second lens group LG2 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 has eight lenses, the optical filter 500 may be disposed between the eighth lens 108 and the image sensor 300.

[0067] The optical filter 500 may include an infrared filter. The optical 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. As another example, a cover glass may also be provided between the optical filter 500 and the image sensor 300.

[0068] The optical system 1000 according to an embodiment may include an aperture stop ST. The aperture stop ST may be a stop for adjusting the amount of light incident on the optical system 1000. The aperture stop ST may be disposed around at least one lens of the first lens group LG1. For example, the aperture stop ST may be disposed around the object-side surface or the sensor-side surface of the second lens 102. The aperture stop ST may be disposed between two adjacent lenses 101 and 102 among the lenses of the first lens group LG1. Alternatively, at least one lens selected from the plurality of lenses 100 may be used as the aperture stop. Specifically, the object-side surface or the sensor-side surface of one lens selected from the lenses of the first lens group LG1 may be used as the aperture stop for adjusting the amount of light.

[0069] The straight-line distance from the aperture stop ST to the sensor-side surface of the nth lens may be less than the optical axis distance from the object-side surface of the first lens 101 to the sensor-side surface of the nth lens. When SD is the distance on the optical axis from the aperture stop ST to the sensor-side surface of the nth lens, the following may be satisfied: SD < EFL and / or SD < Imgh. In addition, the following condition may be satisfied: SD < TTL. EFL is the effective focal length of the entire optical system and may be defined as F. The following condition may be satisfied: F ≤ Imgh, and the difference between F and Imgh may be 0.5 mm or less. The FOV of the optical system 1000 may be less than 120 degrees, for example, greater than 70 degrees and less than 100 degrees. The F-number (F#) of the optical system 1000 may be greater than 1 and less than 10. For example, 1.1 ≤ F# ≤ 5. In addition, F# may be less than the entrance pupil diameter (EPD). Therefore, the optical system 1000 has a thin size, can control incident light, and can have improved optical characteristics within the FOV.

[0070] The effective diameter of the lens may gradually decrease from the object-side lens to the lens surface between the first lens group LG1 and the second lens group LG2, and may gradually increase from the lens surface between the first lens group LG1 and the second lens group LG2 to the lens surface of the last lens.

[0071] The optical system 1000 according to an embodiment may further include a reflecting member (not shown) for changing the optical path. The reflecting member may be implemented as a prism that reflects the incident light of the first lens group LG1 toward the lens. The optical system according to an embodiment will be described in detail below.

[0072] Figure 1 is a configuration diagram of an optical system and a camera module according to an embodiment of the present invention, and Figure 2 is a diagram showing Figure 1 the relationship between the image sensor, the nth lens, and the (n - 1)th lens in the optical system of

[0073] refer to Figure 1 and Figure 2 , the optical system 1000 according to the embodiment includes a lens part 100 having a plurality of lenses, and the lens part 100 may include first to eighth lenses 101 to 108. The first to eighth lenses 101 to 108 may be sequentially arranged along the optical axis OA of the optical system 1000. Light corresponding to object information may pass through the first to eighth lenses 101 to 108 and the optical filter 500, and be incident on the image sensor 300.

[0074] The first lens group LG1 may include first to third lenses 101, 102, and 103, and the second lens group LG2 may include fourth to eighth lenses 104 to 108. The optical axis distance between the third lens 103 and the fourth lens 104 may be the distance on the optical axis between the first lens group LG1 and the second lens group LG2.

[0075] In the first to eighth lenses 101 to 108, the number of lenses having a meniscus shape convex toward the object side on the optical axis may be 5 or more, for example, n-2 of the total number of lenses. n is the total number of lenses and may be, for example, 8.

[0076] The first lens 101 may have negative (-) or positive (+) refractive power on the optical axis OA, and preferably may have positive (+) refractive power. The first lens 101 may include a plastic or glass material. For example, the first lens 101 may be made of a plastic material.

[0077] 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 toward the object side on the optical axis OA. 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. The aspherical coefficients of the first surface S1 and the second surface S2 are set as follows: Figure 4 As shown, L1 is the first lens 101, L1S1 is the first surface, and L1S2 is the second surface.

[0078] The second lens 102 may have a positive (+) or negative (-) refractive power on the optical axis OA. The second lens 102 may have a negative (-) 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.

[0079] 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. The fourth surface S4 may have a concave shape. That is, the second lens 102 may have a meniscus shape that is convex toward the object side on the optical axis OA. Alternatively, on the optical axis OA, the third surface S3 may have a convex shape and the fourth surface S4 may have a convex shape. 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. The aspherical coefficients of the third surface S3 and the fourth surface S4 are set as follows Figure 4 As shown, L2 is the second lens 102, L2S1 is the third surface, and L2S2 is the fourth surface.

[0080] The third lens 103 may have positive (+) or negative (-) refractive power on the optical axis OA, and may preferably have positive (+) 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.

[0081] 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 is convex toward the object side on the optical axis OA. Alternatively, on the optical axis OA, the fifth surface S5 may have a concave shape and the sixth surface S6 may have a concave shape. Alternatively, the third lens 103 may have a meniscus shape that is convex toward the sensor side. 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. The aspherical coefficients of the fifth surface S5 and the sixth surface S6 are set as follows Figure 4 As shown, L3 is the third lens 103, L3S1 is the fifth surface, and L3S2 is the sixth surface.

[0082] In the third lens 103, the effective radius of the fifth surface S5 may be greater than the effective radius of the sixth surface S6. The refractive index of the third lens 103 is greater than 1.6, and may be greater than the refractive indexes of the first lens 101 and the second lens 102. The Abbe number of the third lens 103 is less than 50, and may be less than the Abbe numbers of the first lens 101 and the second lens 102.

[0083] The fourth lens 104 may have a positive (+) or negative (-) refractive power on the optical axis OA. The fourth lens 104 may have a 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. For example, the fourth lens 104 may be made of a plastic material. When expressed in absolute values, the focal length of the fourth lens 104 may be greater than the focal length of the seventh lens 107, for example, the following condition may be satisfied: 5<|F4|-|F7|<30. Here, the following condition may be satisfied: 10<|F4|<25. The fourth lens 104 may have the largest focal length among the lenses.

[0084] 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 that convexes toward the sensor on the optical axis OA. Alternatively, the fourth lens 104 may have a concave shape on both sides of the optical axis. Alternatively, the fourth lens 104 may have a convex shape on both sides of the optical axis OA. At least one or all of the seventh surface S7 and the eighth surface S8 of the fourth lens 104 may not be set with a critical point. At least one of the seventh surface S7 and the eighth surface S8 may be an aspherical surface. For example, both the seventh surface S7 and the eighth surface S8 may be aspherical surfaces, and the aspherical coefficients are set as follows Figure 4 As shown, L4 is the fourth lens 104, L4S1 is the seventh surface, and L4S2 is the eighth surface.

[0085] The effective radius of the sixth surface S6 of the third lens 103 and / or the seventh surface S7 of the fourth lens 104 may be the smallest of the effective diameters of the object-side surface and the sensor-side surface of the lens. The effective radius difference between the sixth surface S6 of the third lens 103 and the seventh surface S7 of the fourth lens 104 may be 0.15 mm or less. Therefore, light loss due to two lens surfaces facing each other in the region between the first lens group LG1 and the second lens group LG2 may be reduced.

[0086] 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.

[0087] 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. On the optical axis OA, the ninth surface S9 may have a concave shape and the tenth surface S10 may have a concave shape. That is, both sides of the fifth lens 105 may have a concave shape on the optical axis OA. Alternatively, the fifth lens 105 may have a meniscus shape convex toward the object side. Alternatively, both sides of the fifth lens 105 may have a convex shape on the optical axis. Alternatively, the fifth lens 105 may have a meniscus shape convex toward the sensor side on the optical axis OA. At least one or all of the ninth surface S9 and the tenth surface S10 of the fifth lens 105 may not be provided with a critical point. 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, and the aspherical coefficients are set as follows Figure 4 As shown, L5 is the fifth lens 105, L5S1 is the ninth surface, and L5S2 is the tenth surface.

[0088] The sixth lens 106 may have a positive (+) or negative (-) refractive power on the optical axis OA. The sixth lens 106 may have a negative (-) 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.

[0089] The sixth lens 106 may include an eleventh surface S11 defined as an object side surface and a twelfth surface S12 defined as a sensor side surface. The eleventh surface S11 may have a concave shape on the optical axis OA, and the twelfth surface S12 may have a concave shape. That is, both sides of the sixth lens 106 may have a concave shape on the optical axis. Alternatively, the sixth lens 106 may have a meniscus shape convex toward the sensor side. Alternatively, the sixth lens 106 may have a meniscus shape convex toward the object side. Alternatively, the sixth lens 106 may have a meniscus shape convex toward the object side. The sixth lens 106 may have a convex shape on both sides. At least one or all of the eleventh surface S11 and the twelfth surface S12 of the sixth lens 106 may not be provided with a critical point. At least one of the eleventh surface S11 and the twelfth surface S12 may be an aspherical surface. For example, both the eleventh surface S11 and the twelfth surface S12 may be aspherical surfaces, and the aspherical coefficients are set as follows Figure 4 , wherein L6 is the sixth lens 106, L6S1 is the eleventh surface, and L6S2 is the twelfth surface.

[0090] The seventh lens 107 may have positive (+) or negative (-) refractive power on the optical axis OA. The seventh lens 107 is an n-1th lens and may have positive (+) refractive power. The seventh lens 107 may include a plastic or glass material. For example, the seventh lens 107 may be made of a plastic material.

[0091] The seventh lens 107 may include a thirteenth surface S13 defined as an object-side surface and a fourteenth surface S14 defined as a sensor-side surface. The thirteenth surface S13 may have a convex shape on the optical axis OA, and the fourteenth surface S14 may have a concave shape on the optical axis OA. That is, the seventh lens 107 may have a meniscus shape that is convex toward the object side on the optical axis OA. Alternatively, the seventh lens 107 may have a meniscus shape that is convex toward the sensor side. Alternatively, the seventh lens 107 may have a shape that is concave on both sides or convex on both sides on the optical axis OA. At least one or both of the thirteenth surface S13 and the fourteenth surface S14 of the seventh lens 107 may have a critical point. At least one of the thirteenth surface S13 and the fourteenth surface S14 may be an aspherical surface. For example, both the thirteenth surface S13 and the fourteenth surface S14 may be aspherical surfaces, and the aspherical coefficients are set as follows Figure 4 As shown, L7 is the seventh lens 107, L7S1 is the thirteenth surface, and L7S2 is the fourteenth surface.

[0092] The eighth lens 108 is an n-th lens and may have a negative (-) refractive power on the optical axis OA. The eighth lens 108 may include a plastic or glass material. For example, the eighth lens 108 may be made of a plastic material. The eighth lens 108 may be a lens closest to the sensor side or the last n-th lens in the optical system 1000.

[0093] The eighth lens 108 may include a fifteenth surface S15 defined as an object-side surface and a sixteenth surface S16 defined as a sensor-side surface. On the optical axis OA, the fifteenth surface S15 may have a convex shape and the sixteenth surface S16 may have a concave shape. That is, the eighth lens 108 may have a meniscus shape that is convex toward the object side on the optical axis OA. Alternatively, the eighth lens 108 may have a meniscus shape that is convex toward the sensor side on the optical axis, or both sides may have a concave shape. At least one or all of the fifteenth surface S15 and the sixteenth surface S16 of the eighth lens 108 may have a critical point. The fifteenth surface S15 and the sixteenth surface S16 may be aspherical surfaces, and the aspherical coefficients are set as follows Figure 4 As shown, L8 is the eighth lens 108, L8S1 is the fifteenth surface, and L8S2 is the sixteenth surface.

[0094] like Figure 2As shown, each of the thirteenth surface S13 and the fourteenth surface S14 of the seventh lens 107 may have at least one critical point P1 or P2 from the optical axis OA to the end of the effective area. Each of the fifteenth surface S15 and the sixteenth surface S16 of the eighth lens 108 may have at least one critical point P3 or P4 from the optical axis OA to the end of the effective area. 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 may represent a point at which the slope is zero. In addition, the critical point may be a point at which the slope value of the tangent line passing through the lens surface increases and then decreases, or a point at which the slope value decreases and then increases.

[0095] The distance from the optical axis OA to the ends of the effective areas of the thirteenth surface S13 and the fourteenth surface S14 of the seventh lens 107 is an effective radius and can be defined as r71 and r72. The distance from the optical axis OA to the ends of the effective areas of each of the fifteenth surface S15 and the sixteenth surface S16 of the eighth lens 108 is an effective radius and can be defined as r81 and r82.

[0096] The distances to the critical points of the thirteenth surface S13, the fourteenth surface S14, the fifteenth surface S15, and the sixteenth surface S16 may be defined as follows.

[0097] Inf71: the straight-line distance from the center of the thirteenth surface S13 to the first critical point P1

[0098] Inf72: Straight-line distance from the center of the fourteenth surface S14 to the second critical point P2

[0099] Inf81: The straight-line distance from the center of the fifteenth surface S15 to the third critical point P3

[0100] Inf82: Straight-line distance from the center of the sixteenth surface S16 to the fourth critical point P4

[0101] The distance to the critical point can have the following relationship.

[0102] Inf72≤Inf71

[0103] Inf81 <Inf71<Inf82

[0104] The effective radii r71, r72, r81, r82 and the distances Inf71, Inf72, Inf81, Inf82 to the critical points P1, P2, P3, P4 from the optical axis can satisfy the following relationship.

[0105] 0.35 <Inf71 / r71<0.50

[0106] 0.32 <Inf72 / r72<0.46

[0107] 0.01 <Inf81 / r81<0.15

[0108] 0.21 <Inf82 / r82<0.35

[0109] The positions of the first critical point P1, the second critical point P2 and the fourth critical point P4 can be located within a range of 2.5 mm or less from the optical axis OA, for example, within a range of 1.1 mm to 2.5 mm, and the third critical point P3 can be located within a range of 1 mm or less based on the optical axis, for example, within a range of 0.1 mm to 1.0 mm.

[0110] The third critical point P3 may be closer to the optical axis OA than the first critical point P1 and the second critical point P2, and the fourth critical point P4 may be closer to the edge than the second critical point P2 and the third critical point P3. Therefore, the seventh lens 107 may refract the incident light to the periphery of the image sensor 300, and the eighth lens 108 may refract the incident light to the peripheral portion of the image sensor 300.

[0111] Considering the optical characteristics of the optical system 1000, it is preferred that the positions of the critical points of the seventh lens 107 and the eighth lens 108 are set at positions satisfying the above range. In detail, the positions of the critical points preferably satisfy the above range to control the optical characteristics of the optical system 1000, such as chromatic aberration, distortion characteristics, aberration characteristics, and resolving power. Therefore, the path of light 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] In addition, a normal line K2 which is a straight line perpendicular to a tangent line K1 passing through an arbitrary point on the sensor-side surface of the sixteenth surface S16 of the eighth lens 108 which is the last lens can have a predetermined angle θ1 with the optical axis OA, and a maximum angle of the angle θ1 can be greater than 5 degrees and less than 65 degrees, for example, in a range of 20 degrees to 50 degrees, or in a range of 20 degrees to 40 degrees. Therefore, since the Sag value in the sensor-side direction based on a straight line orthogonal to the optical axis of the sixteenth surface S16 is not large, a slim optical system can be provided.

[0113] Here, a normal line perpendicular to a tangent line passing through a fifteenth surface S15 of the eighth lens 108 has a second angle θ2 with respect to the optical axis, a normal line perpendicular to a tangent line passing through a fourteenth surface S14 of the seventh lens 107 has a third angle θ3 with respect to the optical axis, and a normal line perpendicular to a tangent line passing through a thirteenth surface S13 of the seventh lens 107 has a fourth angle θ2 with respect to the optical axis. When the first to fourth angles θ1, θ2, θ3, and θ4 are maximum, the following relationship may be satisfied.

[0114] The condition is satisfied: θ1>θ2, and the range of θ1 and θ2 may be 50 degrees or less, for example, from 20 degrees to 50 degrees.

[0115] The condition is satisfied: θ4≤θ2≤θ3<θ1, and the range of θ3 and θ4 may be 50 degrees or less, for example, from 20 degrees to 50 degrees. The difference between the maximum values ​​of the first to fourth angles θ1, θ2, θ3, θ4 may be 10 degrees or less.

[0116] A section in which each of the first to fourth angles θ1, θ2, θ3, θ4 on the thirteenth to sixteenth surfaces S13 to S16 is 30 degrees or more may have the following relationship with respect to the optical axis.

[0117] 5≤θ1≤6.4

[0118] 2.5≤θ2≤3.0

[0119] 3.2≤θ3≤3.9

[0120] 2.8≤θ4≤3.1

[0121] In addition, the positions starting at 30 degrees or more according to these relationships may be in the order of the fifteenth surface S15, the thirteenth surface S13, the fourteenth surface S14, the sixteenth surface S16 from the optical axis.

[0122] On the optical axis,

[0123] The first surface S1 and the second surface S2 of the first lens 101 have curvature radii L1R1 and L1R2,

[0124] The curvature radii of the third surface S3 and the fourth surface S4 of the second lens 102 are L2R1 and L2R2,

[0125] The curvature radii of the fifth surface S5 and the sixth surface S6 of the third lens 103 are L3R1 and L3R2,

[0126] The curvature radii of the seventh surface S7 and the eighth surface S8 of the fourth lens 104 are L4R1 and L4R2,

[0127] The radii of curvature of the ninth surface S9 and the tenth surface S10 of the fifth lens 105 are L5R1 and L5R2,

[0128] The radii of curvature of the eleventh surface S11 and the twelfth surface S12 of the sixth lens 106 are L6R1 and L6R2,

[0129] The radii of curvature of the thirteenth surface S13 and the fourteenth surface S14 of the seventh lens 107 are L7R1 and L7R2,

[0130] The radii of curvature of the fifteenth surface S15 and the sixteenth surface S16 of the eighth lens 108 can be defined as L8R1 and L8R2. The radii of curvature can satisfy at least one of the following conditions 1 to 9 to improve the aberration characteristics of the optical system.

[0131] Condition 1: L1R1 + L1R2 < L2R2

[0132] Condition 2: L2R1 < L2R2

[0133] Condition 3: L3R1 + L3R2 < L2R2

[0134] Condition 4: L8R1 * L8R2 < |L5R2|

[0135] Condition 5: L7R1 + L7R2 < L6R2

[0136] Condition 6: L7R1 * L7R2 < |L5R2| (however, the relationship: L7R1 < L7R2 is satisfied)

[0137] Condition 7: L8R1 + L8R2 < L7R1 + L7R2

[0138] Condition 8: |L6R1 * L6R2| < L3R1 * L3R2

[0139] Condition 9: L4R1 + L4R2 < L5R1 + L5R2 (however, the relationship: L5R1 < L5R2 is satisfied)

[0140] In the optical system, the radius of curvature of the eighteenth surface S18 of the eighth lens 108 can be the smallest, and the difference from the radius of curvature of the first surface S1 of the first lens 101 can be 1 mm or less. The radius of curvature (absolute value) of the tenth surface S10 of the fifth lens 105 can be the largest, or greater than 50 mm. By setting such radii of curvature, good optical performance can be provided at the focal length of each lens.

[0141] The effective diameter of the eighth lens 108 may have a maximum effective diameter and may be 12 mm or more. The effective diameter of the eighth lens 108 is an average of the effective diameters of the object side surface and the sensor side surface. The effective diameter of the eighth lens 106 may be twice or more the radius of curvature (absolute value) of the fifth lens 105.

[0142] On the optical axis,

[0143] The effective diameters of the first surface S1 and the second surface S2 of the first lens 101 are CA_L1S1 and CA_L1S2,

[0144] The effective diameters of the third surface S3 and the fourth surface S4 of the second lens 102 are CA_L2S1 and CA_L2S2,

[0145] The effective diameters of the fifth surface S5 and the sixth surface S6 of the third lens 103 are CA_L3S1 and CA_L3S2,

[0146] The effective diameters of the seventh surface S7 and the eighth surface S8 of the fourth lens 104 are CA_L4S1 and CA_L4S2,

[0147] The effective diameters of the ninth surface S9 and the tenth surface S10 of the fifth lens 105 are CA_L5S1 and CA_L5S2,

[0148] The effective diameters of the eleventh surface S11 and the twelfth surface S12 of the sixth lens 106 are CA_L6S1 and CA_L6S2,

[0149] The effective diameters of the thirteenth surface S13 and the fourteenth surface S14 of the seventh lens 107 are CA_L7S1 and CA_L7S2,

[0150] The effective diameters of the fifteenth surface S16 and the sixteenth surface S16 of the eighth lens 108 may be defined as CA_L8S1 and CA_L8S2. These effective diameters are factors that affect aberration characteristics of the optical system and may satisfy at least one of the following conditions.

[0151] CA_L3S2 <CA_L3S1<CA_L2S1<CA_L1S1

[0152] CA_L5S1 <CA_L5S2<CA_L6S1<CA_L6S2

[0153] CA_L6S2 <CA_L7S1<CA_L7S2<CA_L8S1<CA_L8S2

[0154] CA_L4S1-CA_L3S2 <CA_L3S1–CA_L3S2

[0155] CA_L5S1+CA_L5S2 <CA_L8S2

[0156] L1R1+L1R2 <CA_L8S2

[0157] Among the first to eighth lenses 101 to 108, the third lens 103 may have the smallest average size of the effective diameter of the lens, and the eighth lens 108 may have the largest average size. The size of the effective diameter of the sixth surface S6 or the seventh surface S7 may be the smallest, and the size of the effective diameter of the sixteenth surface S16 may be the largest. The size of the effective diameter of the eighth lens 108 is the largest, so the incident light can be effectively refracted toward the image sensor 300. Therefore, the optical system 1000 can have an improved chromatic aberration control characteristic, and the vignetting characteristic of the optical system 1000 can be improved by controlling the incident light.

[0158] In the optical system, the number of lenses having a refractive index greater than 1.6 may be three or less, and the number of lenses having a refractive index less than 1.6 may be four or more. The average refractive index of the first lens 101 to the eighth lens 108 may be 1.55 or more. In the optical system, the number of lenses having an Abbe number greater than 45 may be equal to the number of lenses having an Abbe number less than 45. The average Abbe number of the first lens to the eighth lens 101 to 108 may be 45 or less. By setting the refractive index and the Abbe number of each lens, the influence of chromatic aberration may be controlled.

[0159] refer to Figure 2, the back focal length (BFL) is the optical axis distance from the image sensor 300 to the last lens. That is, BFL is the distance on the optical axis between the image sensor 300 and the sixteenth surface S16 on the sensor side of the eighth lens 108. CT7 is the center thickness or optical axis thickness of the seventh lens 107, and L7_ET is the end or edge thickness of the effective area of ​​the seventh lens 107. CT8 is the center thickness or optical axis thickness of the eighth lens 108. CG7 is the optical axis distance (i.e., center distance) between the seventh lens 107 and the eighth lens 108. That is, the optical axis distance CG7 between the seventh lens 107 and the eighth lens 108 is the distance between the fourteenth surface S14 and the fifteenth surface S15 on the optical axis OA. CG7 may be greater than the optical axis distance between the third lens 103 and the fourth lens 104. CG7 may be the largest of the optical axis distances between two adjacent lenses. CG7 may be 40% or more, for example, in the range of 40% to 48%, of the optical axis distance from the first surface S1 of the first lens 101 to the fourteenth surface S14 of the seventh lens 107. By increasing the optical axis distance CG7 between the seventh lens 107 and the eighth lens 108, the difference in effective diameters between the seventh lens 107 and the eighth lens 108 may be increased, and a slim optical system with improved optical performance may be provided.

[0160] The center distance CG7 between the seventh lens 107 and the eighth lens 108 is the maximum value among the distances between the lenses, and the optical axis distance between the second lens 102 and the third lens 103 is the minimum among the distances between the lenses. Among the first to eighth lenses 101 to 108, the second lens 102 has the largest center thickness. The center thickness CT2 of the second lens 102 may be smaller than the optical axis distance between the fourth lens 104 and the fifth lens 105, and smaller than the optical axis distance CG7 between the seventh lens 107 and the eighth lens 108. The lens having the smallest center thickness may be the third lens 103.

[0161] Among the lenses 101 to 108, the maximum center thickness may be two or more times the minimum center thickness, for example, 2 to 5 times. Among these lenses, 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 more, and may be four or more. The average value of the center thickness of the lenses may be less than 0.5 mm. The optical system 1000 having an image sensor 300 having a size of about 1 inch may be provided in a structure having a slim thickness.

[0162] In addition, the sum of the center thicknesses of the first to eighth lenses 101 to 108 may be less than the sum of the center distances between the first to eighth lenses 101 to 108. Therefore, the optical system 1000 may control incident light and may have improved aberration characteristics and resolution.

[0163] When the focal lengths of the respective lenses 101 to 108 are defined as F1, F2, F3, F4, F5, F6, F7, and F8, in terms of absolute values, the following conditions can be satisfied: F2 < F4 and F1 < F3, and the following conditions can be satisfied: F8 < F5 < F4. The resolution can be affected by adjusting the focal length. When the focal length is described in terms of absolute value, the focal length of the fourth lens 104 can be the largest among the lenses, and the focal length of the eighth lens 108 is the smallest, and the difference in the focal lengths of the seventh lens 107 and the eighth lens 108 can be 3 or less. The maximum focal length can be 6 times or more the minimum focal length.

[0164] When the refractive indices of the respective lenses 101 to 108 are n1, n2, n3, n4, n5, n6, n7, and n8, and the Abbe numbers of the respective lenses 101 to 108 are v1, v2, v3, v4, v5, v6, v7, and v8, the refractive indices can satisfy the conditions: n1 < n3, n1, n2, n4, n7, and n8 are less than 1.6 and the difference between them is 0.2 or less, and n3, n5, and n6 are greater than 1.60. The Abbe numbers can satisfy the conditions: v3 < v2, v1, v2, v4, and v8 can be 45 or more and the difference between them can be 10 or less, and v3 can be less than 45, for example, 30 or less. Accordingly, the optical system 1000 can have improved chromatic aberration control characteristics.

[0165] The optical system 1000 according to the embodiments disclosed above can satisfy at least one or two or more of the following mathematical formulas. Accordingly, the optical system 1000 according to the embodiments can have improved optical characteristics. For example, when the optical system 1000 satisfies at least one mathematical formula, the optical system 1000 can effectively control aberration characteristics such as chromatic aberration and distortion aberration, and has good optical performance not only in the central portion of the FOV but also in the peripheral portion. The optical system 1000 can have improved resolution, and can have a thinner and more compact structure.

[0166] Hereinafter, the central thicknesses of the first lens to the eighth lens 101 to 108 can be defined as CT1-CT8, the edge thicknesses can be defined as ET1-ET8, and the optical axis distances between adjacent two lenses from the distance between the first lens and the second lens to the distance between the seventh lens and the eighth lens can be defined as CG1 to CG7, and the distances between the edges of adjacent two lenses from the distance between the first lens and the second lens to the distance between the seventh lens and the eighth lens can be defined as EG1 to EG8. The units of the thickness and the distance are mm.

[0167] [Mathematical formula 1] 0 < CT1 / CT2 < 1.5

[0168] In Math 1, when the thickness CT1 of the first lens 101 on the optical axis OA and the thickness CT2 of the second lens 102 on the optical axis OA are satisfied, the optical system 1000 can improve aberration characteristics. Preferably, Math 1 above can satisfy: 0.5≤CT1 / CT2<1.

[0169] [Math 2]0 <CT3 / ET3<1.5

[0170] In Math 2, when the thickness CT3 of the third lens 103 on the optical axis and the thickness ET3 of the third lens 103 at the edge of the effective area are satisfied, the optical system 1000 may have a chromatic aberration control characteristic. Preferably, Math 2 may satisfy: <CT3 / ET3≤1。

[0171] [Mathematical formula 2-1]2 <CT1 / ET1<3

[0172] [Mathematical formula 2-2]1 <CT2 / ET2<3

[0173] [Mathematical formula 2-3] (CT2–CT1) <CT3

[0174] [Mathematical formula 2-4]1 <CT4 / ET4<2

[0175] [Mathematical formula 2-5]1 <CT5 / ET5<2

[0176] [Mathematical formula 2-6] 0.8 <CT6 / ET6<1.2

[0177] [Mathematical formula 2-7]2 <CT7 / ET7<3

[0178] [Mathematical formula 2-8]0 <CT8 / ET8<1.2

[0179] [Mathematical formula 2-9] 0.5 <SD / TD<1

[0180] When the ratio of the center thickness to the edge thickness of the second to eighth lenses 102 to 108 in Math. 2-1 to Math. 2-8 is satisfied, the optical system 1000 may have improved chromatic aberration control characteristics. SD is an optical axis distance from the aperture stop to the sensor-side sixteenth surface S16 of the eighth lens 108, and TD is an optical axis distance from the object-side first surface S1 of the first lens 101 to the sensor-side sixteenth surface S16 of the eighth lens 108. The aperture stop may be provided around the object-side surface of the second lens 102. When the optical system 1000 according to the embodiment satisfies Math. 2-9, chromatic aberration of the optical system 1000 may be improved.

[0181] [Mathematical formula 2-10]3 <F_LG2 / F_LG1<5

[0182] F_LG1 is the focal length of the first lens group LG1, and F_LG2 is the focal length of the second lens group LG2. When the optical system 1000 according to the embodiment satisfies Math. 2-10, the chromatic aberration of the optical system 1000 can be improved. That is, when the value of Math. 2-10 is close to 1, the distortion aberration can be reduced. The value of Math. 2-10 can satisfy: 3 <F_LG2 / F_LG1<4。

[0183] [Math 3]0 <ET8 / CT8<3

[0184] In Math 3, when the thickness CT8 of the eighth lens 108 at the optical axis and the thickness ET8 at the edge are satisfied, the optical system 1000 may have improved chromatic aberration control characteristics. Math 3 may satisfy: 1≤ET8 / CT8<2. In addition, the condition: CT6+CT7+CT8 may be satisfied. <CG7。

[0185] [Math 4] 1.6 <n3

[0186] In Math 4, 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 4, the optical system 1000 may improve chromatic aberration characteristics.

[0187] [Mathematical formula 4-1]

[0188] 1.50 <n1<1.60

[0189] 1.50 <n8<1.60

[0190] In Math 4-1, n1 is the refractive index of the first lens 101 at the d-line, and n8 is the refractive index of the eighth lens 108 at the d-line. When the optical system 1000 according to the embodiment satisfies Math 4-1, the influence on the TTL of the optical system 1000 can be suppressed.

[0191] [Mathematical formula 4-2]

[0192] 1.50 <n2<1.60

[0193] 1.50 <n4<1.60

[0194] In Math 4-2, n2 and n4 are refractive indices of the second lens 102 and the fourth lens 104 at the d-line. When the optical system 1000 according to the embodiment satisfies Math 4-2, the optical system 1000 may improve chromatic aberration characteristics.

[0195] [Formula 5]

[0196] 0.5 <L8S2_max_Sag to Sensor<1.5

[0197] In Math 5, L8S2_max_Sag to Sensor represents the distance from the maximum Sag value of the sensor-side sixteenth surface S16 of the eighth lens 108 to the image sensor 300 in the optical axis direction. For example, L8S2_max_Sag to Sensor represents the distance from the critical point P4 of the sensor-side surface of the eighth lens 108 to the image sensor 300 in the optical axis direction. When the optical system 1000 according to the embodiment satisfies Math 5, the optical system 1000 can ensure a space in which the optical filter 500 can be disposed between the lens portion 100 and the image sensor 300, thereby having improved assemblability. In addition, when the optical system 1000 satisfies Math 5, the optical system 1000 can ensure a distance for module manufacturing. Preferably, the value of Math 5 can satisfy: 0.8 <L8S2_max_sag to Sensor<1.2。

[0198] In the lens data of the embodiment, the position of the filter 500 (specifically, the distance between the last lens and the filter 500, and the distance between the image sensor 300 and the filter 500) is set to facilitate the design of the optical system 1000, and the filter 500 can be freely set within the range where the last lens does not contact the image sensor 300. Therefore, the value of L8S2_max_Sag to Sensor in the lens data can be smaller than the BFL of the optical system 1000, and the position of the filter 500 can be moved within the range where it does not contact the last lens and the image sensor 300, respectively, and has good optical performance. That is, the distance between the critical point P4 on the sixteenth surface S16 of the eighth lens 108 and the image sensor 300 is the smallest, and can be gradually increased toward the end of the effective area.

[0199] [Math 6] 0.8 <BFL / L8S2_max_Sag to Sensor<2

[0200] In Mathematical Formula 6, BFL represents the distance (unit: mm) from the center of the sixteenth surface S16 of the eighth lens 108 on the optical axis OA to the image surface of the image sensor 300. When the optical system 1000 according to the embodiment satisfies Mathematical Formula 6, the optical system 1000 can improve the distortion aberration characteristics and can have good optical performance in the peripheral part of the FOV. Here, the L8S2_max_Sag value in the sensor side direction can be the position of the critical point P4. Mathematical Formula 6 can satisfy: 1≤BFL / L8S2_max_sag to Sensor<1.5.

[0201] [Math 7]5<|L8S2_max slope|<65

[0202] In Math 7, L8S2_max slope represents a maximum value (unit: degree) of a tangential angle measured on the sensor-side sixteenth surface S16 of the eighth lens 108. In detail, in the sixteenth surface S16, L8S2_max slope represents an angle value (unit: degree) at a point having a maximum tangential angle relative to a virtual line extending in a direction perpendicular to the optical axis OA. When the optical system 1000 according to the embodiment satisfies Math 7, the optical system 1000 can control the occurrence of lens flare. Preferably, Math 7 can satisfy: 20≤|L8S2_max slope|≤40.

[0203] [Mathematical formula 8]1 <Inf82<2.4

[0204] In Math Formula 8, Inf82 may represent a distance from the optical axis OA to the critical point P4 of the sixteenth surface S15 of the eighth lens 108. Inf82 may be located within a range of 1.8 mm ± 0.2 mm from the optical axis OA. When the optical system 1000 according to the embodiment satisfies Formula 8, the influence on the thinness rate of the optical system 1000 may be suppressed.

[0205] [Mathematical formula 9]1 <CG7 / G7_min<3

[0206] Mathematical formula 9 sets the minimum distance G7_min between the distance between the seventh lens 107 and the eighth lens 108 and the distance CG7 between the seventh lens 107 and the eighth lens 108 based on the optical axis OA. When the optical system 1000 according to the embodiment satisfies mathematical formula 9, the optical system 1000 can improve the distortion aberration characteristics and can have good optical performance in the peripheral part of the FOV. Mathematical formula 9 can satisfy: 1 <CG7 / G7_min<2。

[0207] [Mathematical formula 10]1 <CG7 / EG7<5

[0208] In Mathematical Formula 10, when the optical axis distance CG7 between the seventh lens 107 and the eighth lens 108 and the optical axis distance EG8 at the end of the effective area between the seventh lens 107 and the eighth lens 108 are satisfied, good optical performance can be achieved even in the center and peripheral parts of the FOV. In addition, the optical system 1000 can reduce distortion, thereby having improved optical performance. Preferably, Mathematical Formula 10 can satisfy: 1 <CG7 / EG7<2。

[0209] [Mathematical formula 11]0 <CG1 / CG7<1.5

[0210] In Math 11, when the optical axis distance CG1 between the first lens 101 and the second lens 102 and the optical axis distance CG7 between the seventh lens 107 and the eighth lens 108 are satisfied, the optical system 1000 can improve aberration characteristics and control the size of the optical system 1000, for example, TTL is reduced. Preferably, Math 11 can satisfy: <CG1 / CG7<1。

[0211] [Mathematical formula 11-1]3 <CA_L8S2 / CG7<20

[0212] In Math 11-1, CA_L8S2 is the effective diameter of the largest lens surface, and is the size of the effective diameter of the sixteenth surface S16 of the eighth lens 108. When the optical system 1000 according to the embodiment satisfies Math 11-1, the optical system 1000 can improve aberration characteristics and control TTL reduction. Preferably, Math 11-1 can satisfy: <CA_L8S2 / CG7<10。

[0213] [Mathematical formula 11-2]1 <CA_L7S2 / CG7<5

[0214] Mathematical formula 11-2 can set the effective diameter CA_L7S2 of the fourteenth surface S14 of the seventh lens 107 and the optical axis distance CG7 between the seventh lens 107 and the eighth lens 108. When the optical system 1000 according to the embodiment satisfies mathematical formula 11-2, the optical system 1000 can improve the aberration characteristics and control TTL reduction. Preferably, mathematical formula 11-2 can satisfy: <CA_L7S2 / CG7<4.5。

[0215] [Math 12]0 <CT1 / CT7<2

[0216] In Math 12, when the thickness CT1 of the first lens 101 on the optical axis OA and the thickness CT7 of the seventh lens 107 on the optical axis OA are satisfied, the optical system 1000 may have improved aberration characteristics. In addition, the optical system 1000 has good optical performance under a set FOV and can control TTL. Preferably, Math 12 may satisfy: 0.5 <CT1 / CT7<1.5。

[0217] [Math 13]0 <CT6 / CT7<3

[0218] In Mathematical Expression 13, when the thickness CT6 of the sixth lens 106 on the optical axis OA and the thickness CT7 of the seventh lens 107 on the optical axis are satisfied, the optical system 1000 can relax the manufacturing precision of the seventh lens 107 and the eighth lens 108, and can improve the optical performance of the central and peripheral portions of the FOV. Preferably, Mathematical Expression 13 can satisfy: 0 < CT6 / CT7 < 1. The central thicknesses of the fifth, sixth, and seventh lenses can satisfy the following condition: CT7 > (CT5 + CT6). In addition, the central thicknesses of the first, sixth, seventh, and eighth lenses can satisfy the following condition: CT6 < CT8 < CT7.

[0219] [Mathematical Expression 14] 0 < |L7R2 / L8R1| < 2

[0220] In Mathematical Expression 14, L7R2 represents the radius of curvature (unit: mm) of the fourteenth surface S14 of the seventh lens 107 on the optical axis, and L8R1 represents the radius of curvature of the fifteenth surface S15 of the eighth lens 108 on the optical axis. When the optical system 1000 according to the embodiment satisfies Mathematical Expression 14, the aberration characteristics of the optical system 1000 can be improved. Preferably, Mathematical Expression 14 can satisfy: 1 < |L7R2 / L8R1| < 2.

[0221] [Mathematical Expression 15] 0 < (CG7 - EG7) / (CG7) < 1

[0222] When Mathematical Expression 15 satisfies the central distance CG7 and the marginal distance EG7 between the seventh lens 107 and the eighth lens 108, the optical system 1000 can reduce distortion and has improved optical performance. When the optical system 1000 according to the embodiment satisfies Mathematical Expression 15, the optical performance of the central and peripheral portions of the FOV can be improved. Preferably, Mathematical Expression 15 can satisfy: 0.1 < (CG7 - EG7) / (CG7) < 0.8. Here, comparing the central distances CG among the fourth, fifth, sixth, seventh, and eighth lenses, the following condition can be satisfied: CG6 < CG5 < CG4 < CG7.

[0223] [Mathematical Expression 16] 1 < CA_L1S1 / CA_L2S2 < 2

[0224] In Mathematical Expression 16, CA_L1S1 represents the effective diameter CA (clear aperture) of the first surface S1 of the first lens 101, and CA_L2S2 represents the effective diameter of the fourth surface S4 of the second lens 102. When the optical system 1000 according to the embodiment satisfies Mathematical Expression 16, the optical system 1000 can control the light incident on the first lens group LG1 and can have improved aberration control characteristics. Preferably, Mathematical Expression 16 can satisfy: 1 < CA_L1S1 / CA_L2S2 < 1.5.

[0225] [Mathematical formula 17]1 <CA_L7S2 / CA_L3S1<5

[0226] In Math 17, CA_L3S1 represents an effective diameter of the fifth surface S5 of the third lens 103, and CA_L7S2 represents an effective diameter of the fourteenth surface S14 of the seventh lens 107. When the optical system 1000 according to the embodiment satisfies Math 17, the optical system 1000 can control light incident to the second lens group LG2 and can improve aberration characteristics. Preferably, Math 17 can satisfy: 2 <CA_L7S2 / CA_L3S1<3

[0227] [Math 18] 0.5 <CA_L3S2 / CA_L4S1<1.5

[0228] In Math 18, when the effective diameter CA_L3S2 of the sixth surface S6 of the third lens 103 and the effective diameter CA_L4S1 of the seventh surface S7 of the fourth lens 104 are satisfied, the difference in effective diameter between the first lens group LG1 and the second lens group LG2 can be reduced, and light loss can be suppressed. In addition, the optical system 1000 can improve chromatic aberration and control vignetting to obtain optical performance. Preferably, Math 18 can satisfy: 0.7 <CA_L3S2 / CA_L4S1<1.3。

[0229] [Mathematical formula 19] 0.1 <CA_L5S2 / CA_L7S2<1

[0230] In Math 19, when the effective diameter CA_L5S2 of the tenth surface S10 of the fifth lens 105 and the effective diameter CA_L7S2 of the fourteenth surface S14 of the seventh lens 107 are satisfied, the optical path to the second lens group LG2 can be set. In addition, the optical system 1000 can improve chromatic aberration. Preferably, Math 19 can satisfy: 0.4≤CA_L5S2 / CA_L7S2≤0.8.

[0231] [Mathematical formula 20]1 <CA_L8S2 / CA_L1S1<5

[0232] In Math 20, when the effective diameter CA_L8S1 of the sixteenth surface S16 of the eighth lens 109 and the effective diameter CA_L1S1 of the first surface S1 of the first lens 101 are satisfied, the effective diameter between the incident side lens and the last lens can be set. Therefore, the optical system 1000 can set the FOV and the size of the optical system. Preferably, Math 20 can satisfy: 2 <CA_L8S2 / CA_L1S1<3.5。

[0233] [Mathematical formula 21]5 <CG3 / EG3<15

[0234] In Math 21, when the distance CG3 between the third lens 103 and the fourth lens 104 and the edge distance EG3 between the third lens 103 and the fourth lens 104 are satisfied on the optical axis OA, the optical system 1000 can reduce chromatic aberration, improve aberration characteristics, and control vignetting to obtain optical performance. Preferably, Math 21 can satisfy: <CG3 / EG3<13。

[0235] [Math 22]0 <CG6 / EG6<1

[0236] In Math Formula 22, when the center distance CG6 and the edge distance EG6 between the sixth lens 106 and the seventh lens 107 are satisfied, the optical system can have good optical performance even in the central and peripheral parts of the FOV, and distortion can be prevented from occurring.

[0237] At least one of Math 21 and Math 22 may further include at least one of Math 22-1 to Math 22-6.

[0238] [Mathematical formula 22-1]0 <CG1 / EG1<1

[0239] [Mathematical formula 22-2]0 <CG2 / EG2<0.5

[0240] [Mathematical formula 22-3]5 <CG4 / EG4<15

[0241] [Mathematical formula 22-4]1 <CG5 / EG5<3

[0242] [Mathematical formula 22-5] 1<(CG6 / EG6)*n<10

[0243] [Mathematical formula 22-6]1 <CG7 / EG7<3

[0244] Here, n is the total number of lenses.

[0245] [Math 23]0 <G7_max / CG7<2

[0246] In Math 23, G7_Max represents the maximum distance among the distances (unit: mm) between the seventh lens 107 and the eighth lens 108. When the optical system 1000 according to the embodiment satisfies Math 23, the optical performance in the peripheral part of the FOV can be improved, and the distortion of the aberration characteristics can be suppressed. Preferably, Math 23 can satisfy: 0.5 <G7_max / CG7<1.5。

[0247] [Math 24]0 <CT6 / CG7<2

[0248] In Math 24, when the thickness CT6 of the sixth lens 106 on the optical axis OA and the distance CG7 between the seventh lens 107 and the eighth lens 108 on the optical axis OA are satisfied, the optical system 1000 can set the maximum optical axis distance CG7 and the center thickness of the sixth lens and improve the optical performance of the peripheral portion of the FOV. Preferably, Math 24 can satisfy: <CT6 / CG7<1。

[0249] [Mathematical formula 25]2 <CG7 / CT6<9

[0250] In Math 25, when the thickness CT6 of the sixth lens 106 on the optical axis OA and the distance CG7 between the seventh lens 107 and the eighth lens 108 are satisfied, the optical system 1000 can reduce the size of the effective diameters of the sixth lens 106 and the seventh lens 107 and the distance between the lenses, and improve the optical performance of the peripheral portion of the FOV. Preferably, Math 25 can satisfy: 4 <CG7 / CT6<8。

[0251] [Mathematical formula 26]1 <CG7 / CT7<5

[0252] When Math. 26 satisfies the thickness CT7 of the seventh lens 107 on the optical axis OA and the distance CG7 between the seventh lens 107 and the eighth lens 108, the optical system 1000 can reduce the size of the effective diameter of the seventh lens and the center distance between the seventh lens and the eighth lens, and improve the optical performance of the peripheral portion of the FOV. Preferably, Math. 26 can satisfy: 2 <CG7 / CT7<4。

[0253] [Math 27] 100<|L5R2 / CT5|<300

[0254] When Math 27 satisfies the curvature radius L5R2 of the tenth surface S10 of the fifth lens 105 and the thickness CT5 of the fifth lens 105 on the optical axis, the optical system 1000 can control the refractive power of the fifth lens 105 and improve the optical performance of the light incident to the second lens group LG2. Preferably, Math 27 can satisfy: 200<|L5R2 / CT5|<260. Preferably, the following condition can be satisfied: L5R2>0.

[0255] [Mathematical formula 28] 2<|L5R1 / L7R1|<10

[0256] When the mathematical formula 28 satisfies the curvature radius L5R1 of the ninth surface S9 of the fifth lens 105 and the curvature radius L7R1 of the thirteenth surface S13 of the seventh lens 107, the optical performance can be improved by controlling the shapes and refractive powers of the fifth lens and the seventh lens, and the optical performance of the second lens group LG2 can be improved. Preferably, the mathematical formula 28 can satisfy: 5 < L5R1 / L7R1 < 8. Preferably, the following conditions can be satisfied: L5R1 < 0.

[0257] [Mathematical formula 29] 0 < L1R1 / L1R2 < 1

[0258] The mathematical formula 29 can set the curvature radii L1R1 and L1R2 of the object-side first surface S1 and the second surface S2 of the first lens 101. When they are satisfied, the lens size and resolution can be determined. Preferably, the mathematical formula 29 can satisfy: 0.3 < L1R1 / L1R2 ≤ 0.9. Preferably, the following conditions can be satisfied: L1R1 > 0 and L1R2 > 0.

[0259] [Mathematical formula 30] 1 < L2R2 / L2R1 < 5

[0260] The mathematical formula 30 can set the curvature radii L2R1 and L2R2 of the object-side third surface S3 and the fourth surface S4 of the second lens 102. When these are satisfied, the resolution of the lens can be determined. Preferably, the mathematical formula 30 can satisfy: 2 < L2R2 / L2R1 ≤ 3. Preferably, the following conditions can be satisfied: L2R1 > 0 and L2R2 > 0.

[0261] At least one of the mathematical formula 28, the mathematical formula 29, and the mathematical formula 30 can include at least one of the following mathematical formulas 30-1 to 30-6, and the resolution of each lens can be determined.

[0262] [Mathematical formula 30-1] 1 < L3R1 / L3R2 < 2

[0263] [Mathematical formula 30-2] 1 < L4R1 / L4R2 < 3

[0264] [Mathematical formula 30-3] 0 < |L5R1 / L5R2| < 1

[0265] [Mathematical formula 30-4] 0 ≤ |L6R1 / L6R2| < 1

[0266] [Mathematical formula 30-5] 0 < L7R1 / L7R2 < 1

[0267] [Mathematical formula 30-6] 3 < L8R2 / L8R1 < 7

[0268] Preferably, the following conditions can be satisfied: L4R1 < 0, L4R2 < 0, L5R1 < 0, L6R1 < 0.

[0269] [Math 31]0 <CT_Max / CG_Max<2

[0270] In Mathematical Formula 31, the maximum thickness CT_max of each lens on the optical axis OA and the maximum value CG_max of the air gap or distance between the multiple lenses on the optical axis are satisfied. In this case, the optical system 1000 has good optical performance under the set FOV and focal length, and the size of the optical system 1000 can be reduced, for example, the TTL can be reduced. Preferably, Mathematical Formula 31 can satisfy: <CT_Max / CG_Max<1。

[0271] [Math 32] 0<ΣCT / ΣCG<2

[0272] In Mathematical Formula 32, ΣCT represents the sum of the thickness (unit: mm) of each lens in the plurality of lenses on the optical axis OA, and ΣCG represents the sum of the distances (unit: mm) between two adjacent lenses in the plurality of lenses on the optical axis OA. When the optical system 1000 according to the embodiment satisfies Mathematical Formula 32, the optical system 1000 has good optical performance at a set FOV and focal length, and the size of the optical system 1000 is reduced, for example, the TTL can be reduced. Preferably, Mathematical Formula 32 can satisfy: 0.5<ΣCT / ΣCG<1.

[0273] [Mathematical formula 33] 10<ΣIndex<30

[0274] In Math 33, ΣIndex represents the sum of the refractive index of each lens at the d-line in the plurality of lenses. When the optical system 1000 according to the embodiment satisfies Math 33, the TTL of the optical system 1000 can be controlled and the resolution can be improved. Here, the average refractive index of the first to eighth lenses 101 to 108 can be 1.50 or greater. Preferably, Math 33 can satisfy: 10<ΣIndex<20 and 80<ΣIndex*n, where n is the total number of lenses.

[0275] [Mathematical formula 34] 10<ΣAbb / ΣIndex<50

[0276] In Math 34, ΣAbbe represents the sum of the Abbe numbers of each lens in the plurality of lenses. When the optical system 1000 according to the embodiment satisfies Math 34, the optical system 1000 may have improved aberration characteristics and resolution. The average Abbe number of the first to eighth lenses 101 to 108 may be 45 or less. Preferably, Math 34 may satisfy: 20<ΣAbb / ΣIndex<40.

[0277] [Math 35]0<|Max_distortion|<5

[0278] In Math 35, Max_distortion represents the maximum value of distortion in the region from the center (0.0F) to the diagonal end (1.0F) based on the optical characteristics detected by the image sensor 300. When the optical system 1000 according to the embodiment satisfies Math 35, the optical system 1000 can improve the distortion characteristics. Preferably, Math 35 can satisfy: 1<|Max_distortion|<3.

[0279] [Math 36]0 <EG_Max / CT_Max<3

[0280] In Math 36, CT_max represents the thickest thickness of each lens on the optical axis OA among the plurality of lenses (unit: mm), and EG_Max represents the maximum edge side distance between two adjacent lenses. When the optical system 1000 according to the embodiment satisfies Math 36, the optical system 1000 has a set FOV and focal length, and can have good optical performance in the peripheral part of the FOV. Preferably, Math 36 can satisfy: 2 <EG_Max / CT_Max<3。

[0281] [Math 37] 0.5 <CA_L1S1 / CA_min<2

[0282] In Math 37, when the effective diameter CA_L1S1 of the first surface S1 of the first lens 101 and the minimum effective diameter CA_Min of the lens surface are satisfied, light incident through the first lens 101 can be controlled, and a slim optical system can be provided while maintaining optical performance. Preferably, Math 37 can satisfy: 1 <CA_L1S1 / CA_min<1.5。

[0283] [Mathematical formula 38]1 <CA_max / CA_min<5

[0284] In Math 38, CA_max represents the maximum effective diameter among the object-side surface and the sensor-side surface of the plurality of lenses, and represents the maximum effective diameter among the effective diameters (unit: mm) of the first to sixteenth surfaces S1-S16. When the optical system 1000 according to the embodiment satisfies Math 38, the optical system 1000 can provide a slim and compact optical system while maintaining optical performance. Preferably, Math 38 can satisfy: <CA_max / CA_min<5。

[0285] [Mathematical formula 39]1 <CA_max / CA_AVR<3

[0286] In Math 39, the maximum effective diameter CA_max and the average effective diameter CA_AVR of the object side surface and the sensor side surface of the plurality of lenses are set, and when these are satisfied, a thin and compact optical system can be provided. Preferably, Math 39 can satisfy: 2 <CA_max / CA_AVR<2.5。

[0287] [Math 40] 0.1 <CA_min / CA_AVR<1

[0288] In Mathematical Formula 40, the minimum effective diameter CA_min and the average effective diameter CA_AVR of the object-side surface and the sensor-side surface of the plurality of lenses may be set, and when these are satisfied, a thin and compact optical system may be provided. Preferably, Mathematical Formula 40 may satisfy: 0.1 <CA_min / CA_AVR≤0.8。

[0289] [Math 41] 0.1 <CA_max / (2×ImgH)<1

[0290] In Mathematical Formula 41, the maximum effective diameter CA_max of the object side surface and the sensor side surface of the plurality of lenses and the distance ImgH from the center (0.0F) to the diagonal end (1.0F) of the image sensor 300 are set. When this is satisfied, 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, ImgH can be in the range of 4 mm to 15 mm. Preferably, Mathematical Formula 41 can satisfy: 0.5≤CA_max / (2*ImgH)<1.

[0291] [Math 42] 0.1 <TD / CA_max<1.5

[0292] In Math 42, TD is the maximum optical axis distance (unit: mm) from the object side surface of the first lens group LG1 to the sensor side surface of the second lens group LG2. For example, TD is the distance from the first surface S1 of the first lens 101 to the sixteenth surface S16 of the eighth lens 108 on the optical axis OA. When the optical system 1000 according to the embodiment satisfies Math 42, a slim and compact optical system can be provided. Preferably, Math 42 can satisfy: 0.1 <TD / CA_max<0.8。

[0293] [Math 43]0 <F / L7R2<5

[0294] In Math 43, the total effective focal length F of the optical system 1000 and the curvature radius L7R2 of the fourteenth surface S14 of the seventh lens 107 may be set. When these are satisfied, the optical system 1000 may reduce the size of the optical system 1000, such as TTL. Preferably, Math 43 may satisfy: <F / L7R2<1。

[0295] Mathematical formula 43 may also include the following mathematical formula 43-1.

[0296] [Mathematical formula 43-1]2 <F / F#<8

[0297] F# can represent the F number. Preferably, mathematical formula 43-1 can satisfy: 2 <F / F#<5。

[0298] [Mathematical formula 43-2]1 <F / L8R2<5

[0299] Mathematical formula 43-2 can set the total effective focal length F of the optical system 1000 and the curvature radius L8R2 of the sixteenth surface S16 of the eighth lens 108. Preferably, mathematical formula 43-2 can satisfy 2 <F / L8R2<4。

[0300] [Mathematical formula 44]1 <F / L1R1<10

[0301] In Math 44, the curvature radius L1R1 of the first surface S1 of the first lens 101 and the total effective focal length F may be set, and when they are satisfied, the size of the optical system 1000 may be reduced, for example, the TTL may be reduced. Preferably, Math 44 may satisfy: 1 <F / L1R1<5。

[0302] [Math 45]0 <EPD / L8R2<5

[0303] In Math 45, EPD represents an entrance pupil diameter (unit: mm) of the optical system 1000, and L8R2 represents a radius of curvature (unit: mm) of the sixteenth surface S16 of the eighth lens 108. When the optical system 1000 according to the embodiment satisfies Math 45, the optical system 1000 can control the overall brightness and can have good optical performance in the center and peripheral parts of the FOV. Preferably, Math 45 can satisfy: <EPD / L8R2<2。

[0304] Mathematical formula 45 may also include the following mathematical formula 45-1.

[0305] [Mathematical formula 45-1]1 <EPD / F#<3

[0306] [Math 46] 0.5 <EPD / L1R1<8

[0307] Mathematical formula 46 represents the relationship between the entrance pupil diameter of the optical system and the radius of curvature of the first surface S1 of the first lens 101, and can control the incident light. Preferably, mathematical formula 46 can satisfy: 1 < EPD / L1R1 < 2.

[0308] [Mathematical formula 47] 0 < F1 / F2 < 2

[0309] In mathematical formula 47, the focal lengths F1 and F2 of the first lens 101 and the second lens 102 can be set. Therefore, the resolution can be improved by adjusting the refractive power of the incident light of the first lens 101 and the second lens 102, and the TTL can be controlled. Preferably, mathematical formula 47 can satisfy: 0 < F1 / F2 < 1, and the following conditions can be satisfied: F1 > 0 and F2 > 0.

[0310] [Mathematical formula 48] 1 < F13 / F < 5

[0311] In mathematical formula 48, since the combined focal length F13 of the first lens to the third lens and the total focal length F are set, the optical system 1000 can improve the resolution by adjusting the refractive power of the incident light, and the TTL of the optical system 1000 can be controlled. Preferably, mathematical formula 48 can satisfy: 1 < F13 / F < 1.5.

[0312] [Mathematical formula 49] 1 < |F48 / F13| < 4

[0313] In mathematical formula 49, the combined focal length F13 of the first lens to the third lens (i.e., the focal length of the first lens group) (unit: mm) and the combined focal length F48 of the fourth lens to the eighth lens (i.e., the focal length of the second lens group) can be set, and when this is satisfied, the resolution can be improved by controlling the refractive power of the first lens group and the second lens group, and the optical system can be provided in a thin and compact size. In addition, when mathematical formula 49 is satisfied, the optical system 1000 can improve aberration characteristics such as chromatic aberration and distortion aberration. Preferably, the above mathematical formula 49 can satisfy: 2 < |F48 / F13| < 3. Here, the following conditions can be satisfied: F13 > 0 and F48 < 0.

[0314] [Mathematical formula 50] 0 < F1 / F < 3

[0315] In mathematical formula 50, the total focal length F and the focal length of the first lens 101 can be set, and the resolution can be improved. Mathematical formula 50 can satisfy: 0 < F1 / F < 2, and the following conditions can be satisfied: F > 0.

[0316] [Mathematical formula 50-1] 1 < F2 / F < 5 (where F2 > 0)

[0317] [Formula 50-2] 1 < |F3 / F2| < 5 (where F3 < 0)

[0318] [Formula 50-3] 3 < F4 / F < 10 (where F4 > 0)

[0319] [Formula 50-4] 1 < |F5| / F < 5 (where F5 < 0)

[0320] [Formula 50-5] 1 < |F6| / F < 4 (where F6 < 0)

[0321] [Formula 50-6] 0 < F7 / F < 1 (where F7 > 0)

[0322] [Formula 50-7] 0 < |F8| / F < 1 (where F8 < 0)

[0323] In Formulas 50-1 to 50-7, F3, F4, F5, F6, F7, and F8 represent the focal lengths (unit: mm) of the third lens 103, the fourth lens 104, the fifth lens 105, the sixth lens 106, the seventh lens 107, and the eighth lens 108. When this condition is met, the resolution can be improved by controlling the refractive power of each lens, and an optical system can be provided in a thin and compact size.

[0324] [Formula 51] 0 < F1 / F13 < 2

[0325] In Formula 51, the resolution of the first lens group can be adjusted by setting the focal length F1 of the first lens and the combined focal length F13 of the first lens to the third lens. Preferably, Formula 51 can satisfy: 1 < F1 / F13 < 2.

[0326] [Formula 52] 0 < F1 / |F48| < 2

[0327] In Formula 52, the size and resolution of the optical system can be adjusted by setting the focal length F1 of the first lens and the combined focal length F48 of the fourth lens to the eighth lens. Preferably, Formula 52 can satisfy: 0 < F1 / |F48| < 1.

[0328] [Formula 53] 0 < |F1 / F4| < 1

[0329] In Formula 53, by setting the focal length F1 of the first lens and the focal length F4 of the fourth lens, the refractive power of the light incident on the first lens group and the second lens group can be controlled, and the size and resolution of the optical system can be adjusted. Preferably, Formula 53 can satisfy: 0 < |F1 / F4| < 0.5.

[0330] [Formula 54] 2 mm < TTL < 20 mm

[0331] In Mathematical Formula 54, the total lens length (TTL) represents the distance (unit: mm) 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. Preferably, Mathematical Formula 54 can satisfy: 5 mm < TTL < 15 mm, thereby providing a thin and compact optical system.

[0332] [Mathematical Formula 55]

[0333] 2 mm < ImgH

[0334] Mathematical Formula 55 sets the diagonal length (2 * ImgH) of the image sensor 300 to be more than 4 mm, thereby providing an optical system with high resolution. Mathematical Formula 55 can preferably satisfy: 4 mm ≤ Imgh ≤ 15 mm or 6 mm ≤ Imgh ≤ 12 mm.

[0335] Mathematical Formula 55 may include at least one of the following Mathematical Formulas 55-1 to 55-4.

[0336] [Mathematical Formula 55-1] 0 < ∑CT / Imgh / < 1

[0337] [Mathematical Formula 55-2] 0 < ∑CG / Imgh < 1

[0338] [Mathematical Formula 55-3] 1 < ∑Index / Imgh < 3

[0339] [Mathematical Formula 55-4] 10 < ∑Abbe / Imgh < 50

[0340] Mathematical Formulas 55-1 to 55-4 can establish the relationship between Imgh and the total center thickness of all lenses, the total center distance between lenses, the total refractive index of all lenses, and the total Abbe number of all lenses. Therefore, the resolution and size of the optical system with Imgh of 4 mm or more or 6 mm or more can be adjusted.

[0341] [Mathematical Formula 56] BFL < 2.5 mm

[0342] In Mathematical Formula 56, the back focal length (BFL) is less than 2.5 mm, thereby ensuring the installation space of the filter 500 and improving the assembly of components through the gap between the image sensor 300 and the last lens, and improving the coupling reliability. Preferably, Mathematical Formula 56 satisfies: 0.8 mm < BFL < 2 mm.

[0343] [Mathematical Formula 57] 2 mm < F < 20 mm

[0344] In Mathematical Formula 57, the total focal length F can be set according to the optical system, and preferably, the total focal length F can satisfy: 5 mm < F < 15.

[0345] [Equation 58]

[0346] FOV < 120 degrees

[0347] In Equation 58, FOV represents the field of view of the optical system 1000 and can provide an optical system with an angle less than 120 degrees. The FOV can be greater than 70 degrees, for example, within the range of 70 degrees to 100 degrees.

[0348] [Equation 59] 0.1 < TTL / CA_max < 2

[0349] In Equation 59, by setting the maximum effective diameter CA_max and TTL of the object side surface and the sensor side surface of multiple lenses, a thin and compact optical system can be provided. Preferably, Equation 59 can satisfy: 0.5 < TTL / CA_max < 1.

[0350] [Equation 60] 0.5 < TTL / ImgH < 3

[0351] Equation 60 can set the total optical axis length (TTL) of the optical system and the diagonal length (ImgH) from the optical axis in the image sensor 300. When the optical system 1000 according to the embodiment satisfies Equation 60, the optical system 1000 ensures a BFL to apply a relatively large-sized image sensor 300, for example, a large-sized image sensor 300 of about 1 inch, and can have a smaller TTL and can have a high-definition implementation and a thin structure. Preferably, Equation 60 can satisfy: 0.8 < TTL / ImgH < 2. Preferably, the following conditions can be satisfied: Imgh > TTL and 50 < TTL * Imgh < 90.

[0352] [Equation 61] 0.01 < BFL / ImgH < 0.5

[0353] Equation 61 can set the distance on the optical axis between the image sensor 300 and the last lens and the length from the optical axis in the diagonal direction in the image sensor 300. When the optical system 1000 according to the embodiment satisfies Equation 61, the optical system 1000 can ensure a BFL to apply a relatively large image sensor 300, for example, a relatively large image sensor 300 of about 1 inch, and minimize the distance between the last lens and the image sensor 300, so as to have good optical characteristics at the center and peripheral parts of the FOV. Preferably, Equation 61 can satisfy: 0.1 ≤ BFL / Imgh ≤ 0.3.

[0354] [Equation 62] 4 < TTL / BFL < 10

[0355] Mathematical formula 62 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). When the optical system 1000 according to the embodiment satisfies mathematical formula 62, the optical system 1000 ensures BFL and can be set to be slim and compact. Mathematical formula 62 can satisfy: <TTL / BFL<10。

[0356] [Math 63] 0.5 <F / TTL<1.5

[0357] Mathematical formula 63 can set the total focal length F and the total optical axis length TTL of the optical system 1000. Therefore, a thin and compact optical system can be provided. Preferably, mathematical formula 63 can satisfy: 0.5 <F / TTL<1.2。

[0358] [Mathematical formula 63-1]0 <F# / TTL<0.5

[0359] Math 63-1 can set the F number F# and the total optical axis length TTL of the optical system 1000. Therefore, a slim and compact optical system can be provided.

[0360] [Mathematical formula 64]3 <F / BFL<10

[0361] Mathematical formula 64 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. When the optical system 1000 according to the embodiment satisfies mathematical formula 64, 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 the optical system 1000 can have good optical characteristics in the peripheral part of the FOV. Preferably, mathematical formula 64 can satisfy: 4 <F / BFL<8。

[0362] [Math 65] 0.1 <F / ImgH<3

[0363] Mathematical formula 65 can set the total focal length F (unit: mm) of the optical system 1000 and the diagonal length (ImgH) from the optical axis in the image sensor 300. The optical system 1000 can have improved aberration characteristics by applying a relatively large image sensor 300 (e.g., a larger image sensor 300 of about 1 inch). Preferably, mathematical formula 65 can satisfy: 0.8≤F / ImgH<2.

[0364] [Mathematical formula 66]1 <F / EPD<5

[0365] Mathematical formula 66 can set the total focal length F (unit: mm) and the entrance pupil diameter of the optical system 1000. Therefore, the overall brightness of the optical system can be controlled. Preferably, mathematical formula 66 can satisfy: 1.5 ≤ F / EPD < 4.

[0366] [Mathematical formula 67] 0 < BFL / TD < 0.3

[0367] In mathematical formula 67, the optical axis distance BFL between the image sensor 300 and the last lens and the optical axis distance TD of the lens are set, and when these are satisfied, the optical system 1000 can provide a thin and compact optical system. Preferably, mathematical formula 67 can satisfy: 0 < BFL / TD ≤ 0.2. When BFL / TD exceeds 0.3, since BFL is designed to be relatively large compared to TD, the size of the entire optical system increases, making it difficult to miniaturize the optical system. Also, since the distance between the eighth lens and the image sensor increases, the amount of unnecessary light passing through the eighth lens and the image sensor may increase. Therefore, there is a problem of reduced resolution, such as a decline in aberration characteristics.

[0368] [Mathematical formula 68] 0 < EPD / Imgh / FOV < 0.2

[0369] In mathematical formula 68, the relationship between the size of EPD, half of the maximum diagonal length of the image sensor (ImgH), and FOV can be set. Therefore, the overall size and brightness of the optical system can be controlled. Preferably, mathematical formula 68 can satisfy: 0 < EPD / Imgh / FOV < 0.1.

[0370] [Mathematical formula 69] 10 < FOV / F# < 55

[0371] Mathematical formula 69 can establish the relationship between the FOV and the F-number of the optical system. Preferably, mathematical formula 69 satisfies: 30 < FOV / F# < 50.

[0372] [Mathematical formula 70] 0 < n1 / n2 < 1.5

[0373] When the refractive indices n1 and n2 of the first lens 101 and the second lens 102 at the d-line in mathematical formula 70 satisfy the above range, the optical system can improve the resolution of the incident light. Preferably, it can satisfy: 0.5 < n1 / n2 ≤ 1.

[0374] [Mathematical formula 71] 0 < n3 / n4 < 1.5

[0375] When the refractive indices n3 and n4 of the third lens 103 and the fourth lens 104 at the d line in Mathematical Formula 71 satisfy the above range, the optical system can improve the resolution of the incident light of the second lens group LG2. Preferably, Mathematical Formula 71 can satisfy: <n3 / n4≤1.5。

[0376] [Math 72] 0.8 <Inf71 / Inf72<1.5

[0377] In Math 72, a distance Inf71 from the optical axis OA to a critical point of the object-side surface S13 of the seventh lens 106 and a distance Inf72 from the optical axis OA to a critical point of the sensor-side surface S12 may be set, and when this is satisfied, the curvature aberration of the sixth lens may be controlled. Math 72 may satisfy: 1≤Inf71 / Inf72<1.5.

[0378] [Mathematical formula 73]0 <Inf81 / Inf82<1

[0379] In Mathematical Formula 73, a distance Inf81 from the optical axis OA to the critical point of the fifteenth surface S15 of the eighth lens 108 and a distance Inf82 from the optical axis OA to the critical point of the sixteenth surface S16 of the eighth lens 108 may be set, and when this is satisfied, the curvature aberration of the eighth lens may be controlled. Mathematical Formula 73 may satisfy: <Inf81 / Inf82<0.5。

[0380] [Mathematical formula 74]1 <Inf72 / Inf81<5

[0381] In Math 74, a distance Inf72 from the optical axis OA to the critical point of the sensor side surface S14 of the seventh lens 107 and a distance Inf81 from the optical axis OA to the critical point of the object side surface S15 of the eighth lens 108 can be set, and when this is satisfied, satisfactory aberrations of the seventh lens and the eighth lens can be controlled. Math 74 can satisfy: <Inf72 / Inf81<4。

[0382] [Mathematical formula 75]5<(TTL / Imgh)*n<15

[0383] Preferably, Mathematical Formula 79 may satisfy: 8<(TTL / Imgh)*n<10.

[0384] [Mathematical formula 76]4<(F / Imgh)*n<14

[0385] Preferably, mathematical formula 80 may satisfy: 6<(F / Imgh)*n<11.

[0386] [Mathematical formula 77] 25 < (TD_LG2 / TD_LG1) * n < 55

[0387] [Mathematical formula 78] 15 < (CT_Max + CG_Max) * n < 30

[0388] [Math 79] 40 < (FOV * TTL) / n < 150

[0389] [Math 80](TTL*n) <FOV

[0390] [Mathematical formula 81] (v3*n3)<(v1*n1)

[0391] In Mathematical Formulas 75 to 81, n is the total number of lenses, and the relationship between the optical axis distance TD_LG1 of the first lens group LG1, the optical axis distance TD_LG2 of the second lens group LG2, the maximum center thickness CT_Max of the lenses, the maximum center distance CG_Max, FOV, TTL, etc. can be set according to the total number of lenses. Therefore, the chromatic aberration, resolution, size, etc. of the optical system having 9 or less lenses can be controlled.

[0392] [Mathematical formula 82]

[0393]

[0394] In Mathematical Formula 82, Z is Sag and may represent the distance in the optical axis direction from any position on the aspherical surface to the vertex of the aspherical surface. Y may represent the distance from any position on the aspherical surface to the optical axis in a direction perpendicular to the optical axis. c may represent the curvature of the lens, and K may represent the cone constant. In addition, A, B, C, D, E, and F may represent aspherical constants.

[0395] The optical system 1000 according to the embodiment may satisfy at least one or two or more of Mathematical Formulas 1 to 81. 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 81, the optical system 1000 has improved resolution, and may improve aberration and distortion characteristics. In addition, the optical system 1000 may ensure BFL to apply a large-size image sensor 300, and may minimize the distance between the last lens and the image sensor 300, and may thus have good optical performance in the center and peripheral portions of the FOV. In addition, when the optical system 1000 satisfies at least one of Mathematical Formulas 1 to 81, it may include a relatively large image sensor 300, have a relatively small TTL value, and may provide a thinner and more compact optical system and a camera module having the optical system.

[0396] 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.

[0397] Figure 3 Is based on having Figure 1 An example of lens data for an embodiment of an optical system.

[0398] like Figure 3 As shown, the optical system according to the embodiment shows the curvature radius of the first lens to the eighth lens 101 to 108 on the optical axis OA, the center thickness CT of the lens, the center distance CG between the lenses, the refractive index at the d line (588nm), the Abbe number and the effective radius (semi-aperture) and the focal length.

[0399] The sum of the refractive indices of the multiple lenses 100 is greater than 10, the sum of the Abbe numbers is greater than 300, and the sum of the center thicknesses of all the lenses is 5 mm or less, for example, in the range of 2 mm to 5 mm. The sum of the center distances between the first lens to the eighth lens on the optical axis can be 6 mm or less, for example, in the range of 2 mm to 6 mm, and can be greater than the sum of the center thicknesses of the lenses. In addition, the average value of the effective diameter of each lens surface of the multiple lenses 100 is 8 mm or less, for example, in the range of 3 mm to 8 mm. The average value of the center thickness of each lens can be less than 1 mm, for example, in the range of 0.2 mm to 0.7 mm. The sum of the effective diameters of each lens surface of the multiple lenses 100 is the sum of the effective diameters from the first surface S1 to the sixteenth surface S16, and can be less than 120 mm, for example, in the range of 80 mm to 110 mm.

[0400] like Figure 4 As shown, in an embodiment, at least one or all lens surfaces of the plurality of lenses may include an aspheric surface having a 30th order aspheric coefficient. For example, the first to eighth lenses 101 to 108 may include lens surfaces having a 30th order aspheric coefficient from the first surface S1 to the sixteenth surface S16. As described above, an aspheric surface having a 30th order aspheric coefficient (a value other than "0") can particularly greatly change the aspheric shape of the peripheral portion, thereby being able to well correct the optical performance of the peripheral portion of the FOV.

[0401] like Figure 5As shown, the first to eighth thicknesses T1 to T8 of the first to eighth lenses 101 to 108 can be represented by a distance of 0.1 mm or more in the direction Y from the center to the edge of each lens, and regarding the first distance G1 between the first lens and the second lens, the second distance G2 between the second lens and the third lens, the third distance G3 between the third lens and the fourth lens, the fourth distance G4 between the fourth lens and the fifth lens, the fifth distance G5 between the fifth lens and the sixth lens, the sixth distance G6 between the sixth lens and the seventh lens, and the seventh distance G7 between the seventh lens and the eighth lens, the distance between adjacent lenses can be represented by a distance of 0.1 mm or more in the direction from the center to the edge.

[0402] The maximum thickness and minimum thickness of the first thickness T1 may differ by 1.5 times or more, for example, 1.5 times to 4 times. The maximum distance of the first distance G1 may be 1.1 times or more than the minimum distance, for example, 1.1 times to 2.5 times. The maximum thickness of the second thickness T2 may be 1.1 times or more of the minimum thickness, for example, 1.1 times to 2.5 times. The maximum distance of the second distance G2 may be 3 times or more of the minimum distance, for example, 3 times to 10 times. The maximum thickness of the third thickness T3 may be 1.1 times or more of the minimum thickness, for example, 1.1 times to 3 times. The maximum distance and minimum distance of the third distance G3 may differ by 4 times or more, for example, 4 times to 10 times. The maximum thickness and minimum thickness of the fourth thickness T4 may differ by 1 times or more, for example, 1 times to 2.2 times. The maximum distance and minimum distance of the fourth distance G4 may differ by 1 times or more, for example, 1 times to 2.5 times. The maximum thickness and minimum thickness of the fifth thickness T5 may differ by 1.1 times or more, for example, 1 to 3 times. The maximum distance and minimum distance of the fifth distance G5 may differ by 1.1 times or more, for example, 1.1 to 3 times. The maximum thickness and minimum thickness of the sixth thickness T6 may differ by 1.1 times or more, for example, 1.1 to 3 times. The maximum distance and minimum distance of the sixth distance G6 may differ by 2 times or more, for example, 2 to 10 times. The maximum thickness and minimum thickness of the seventh thickness T7 may differ by 1.1 times or more, for example, 1.1 to 2.5 times. The maximum distance and minimum distance of the seventh distance G7 may differ by 1.1 times or more, for example, 1.1 to 2 times. The maximum thickness and minimum thickness of the eighth thickness T8 may differ by 2 times or more, for example, 2 to 5 times. By using the first to eighth thicknesses T1 to T8 and the first to seventh distances G1 to G7, an optical system can be provided in a slim and compact size.

[0403] Figure 6It can be represented by the height (Sag value) from the straight line in the Y-axis direction orthogonal to the center of the object-side surface L7S1 and the sensor-side surface L7S2 of the seventh lens 107 and the object-side surface L8S1 and the sensor-side surface L8S2 of the eighth lens 108 according to the embodiment of the present invention to the lens surface at every distance of 0.1 mm or more, Fig.11 It is shown Figure 5 . Figure 2 , Figure 6 and Fig.11 As shown, the object-side surface L7S1 and the sensor-side surface L7S2 of the seventh lens 107 have critical points P1 and P2 in a region 2.5 mm or less from the optical axis, and it can be seen that the Sag value of the object-side surface L7S1 is more prominent than the Sag value of the sensor-side surface L7S2 in the sensor-side direction. Also, in the sensor-side direction, the Sag value of the sensor-side surface L8S2 of the eighth lens 108 may be greater than the Sag value of the object-side surface L8S1, and as Figure 2 and Fig.11 As shown, it can be seen that the critical point P3 of the object-side surface of the eighth lens is arranged closer to the optical axis than the other critical points P1, P2 and P4.

[0404] Figure 7 is a graph showing the diffraction MTF characteristics of the optical system according to the embodiment of the present invention, and Figure 8 : is a graph showing aberration characteristics of the optical system according to the embodiment of the present invention.

[0405] like Figure 7 and Figure 8 As shown, in the aberration diagram of the optical system according to the embodiment, there is a diagram measuring spherical aberration, astigmatism field curve and distortion from left to right. The X-axis can represent focal length (mm) and distortion (%), and the Y-axis can represent the height of the image. In addition, the diagram of spherical aberration is a diagram of light with wavelength bands of about 470nm, about 510nm, about 555nm, about 610nm and about 650nm, and the diagram of astigmatism and distortion is a diagram of light with a wavelength band of 555nm. Figure 8 In the aberration diagram of , it can be interpreted that as each curve approaches the Y axis, the aberration correction function is better. Figure 8, in the optical system 1000 according to the embodiment, it can be seen that the measured values ​​are adjacent to the Y axis in almost all areas. That is, the optical system 1000 according to the embodiment can have improved resolution and good optical performance not only in the central part of the FOV but also in the peripheral part. As confirmed by the above-mentioned embodiment, the lens system according to the embodiment of the present invention has a configuration of 9 or less lenses (e.g., 8 lenses), is compact and lightweight, and spherical aberration, astigmatism, distortion aberration, chromatic aberration and coma aberration are all good. Since it can be calibrated and implemented with high resolution, the lens system can be used by an optical device embedded in a camera.

[0406] Fig. 9 A quadratic function closest to a curve passing through the end of the effective area of ​​the object-side surface and the sensor-side surface of each lens in the optical system according to the embodiment is shown. Data from the end of the effective area of ​​the object-side surface of the first lens to the end of the effective area of ​​the sensor-side surface of the eighth lens can be expressed by approximating the quadratic function.

[0407] Quadratic functions can have the following relationships.

[0408] [Function 1]

[0409] y=0.042x 2 -0.4459x+k1

[0410] k1 is a coefficient for setting the position in the y-axis direction, and can be set to 2.7±0.2. In addition, the fitting coefficient (R 2 ) is 0.95 or above, and the closer it is to 1, the closer it is to the function.

[0411] Fig.10 The linear function closest to a straight line from the minimum effective diameter to the maximum effective diameter in the optical system according to the embodiment is shown. For example, data from the end of the effective area of ​​the object-side surface of the fourth lens to the end of the effective area of ​​the sensor-side surface of the eighth lens can be represented by an approximate linear function.

[0412] [Function 2]

[0413] y=0.0531x+k2

[0414] k2 is a coefficient for setting the position in the y-axis direction, and can be set to 0.5±0.05. In addition, the fitting coefficient (R 2 ) is 0.90 or above, and the closer it is to 1, the closer it is to the function.

[0415] like Fig. 9 and Fig.10 As shown, a quadratic function connecting the end of the effective area of ​​each lens and the end of the effective area of ​​the lens with the smallest effective diameter and the end of the effective area of ​​the lens with the largest effective diameter can be given, and the size of the optical system can be optimally set.

[0416] Table 1 relates to the terms of the above mathematical formula in the optical system 1000 according to the embodiment, and relates to TTL, BFL, the total effective focal length F value of the optical system 1000, ImgH, the focal length of each of the first lens to the eighth lens (F1, F2, F3, F4, F5, F6, F7, F8), edge thickness, edge distance, synthetic focal length, etc.

[0417]

Table 1

[0418]

[0419]

[0420] Table 2 for Figure 1 Result values ​​of the above mathematical formulas 1 to 42 in the optical system 1000. Referring to Table 2, it can be seen that the optical system 1000 satisfies at least one, two or more, or three or more of the mathematical formulas 1 to 42. In detail, it can be seen that the optical system 1000 according to the embodiment satisfies all of the mathematical formulas 1 to 42. Therefore, the optical system 1000 can improve the optical performance and optical characteristics of the central part and the peripheral part of the FOV.

[0421]

Table 2

[0422]

[0423]

[0424] Table 3 for Figure 1 Result values ​​of the above mathematical formulas 43 to 81 in the optical system 1000. Referring to Table 3, the optical system 1000 may satisfy at least one or two or more of the mathematical formulas 1 to 42 and at least one, two or more, or three or more of the mathematical formulas 43 to 81. In detail, it can be seen that the optical system 1000 according to the embodiment satisfies all of the mathematical formulas 1 to 81. Therefore, the optical system 1000 can improve the optical performance and optical characteristics at the central part and the peripheral part of the FOV.

[0425]

Table 3

[0426]

[0427]

[0428] Fig.12 2 is a diagram showing that a camera module according to an embodiment is applied to a mobile terminal. Fig.12 , 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.

[0429] 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.

[0430] 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.

[0431] 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 10m 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. 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 the camera operation of the mobile terminal or the control of the user.

[0432] 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, and effects described in each embodiment can be combined or modified by a technician in the field to which the embodiment belongs 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. Although described based on the embodiments, 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. And the differences related to these modifications and applications should be understood to be included in the scope of the present invention defined in the appended claims.

Claims

1. An optical system, comprising: a first lens to an eighth lens, arranged along the optical axis in a direction from the object side to the sensor side, wherein the first lens has a positive (+) refractive power on the optical axis and has a meniscus shape convex toward the object side, wherein the eighth lens has a negative (-) refractive power on the optical axis and has a meniscus shape convex toward the object side, wherein the object side surface of the seventh lens has a critical point, wherein the sensor side surface of the eighth lens has a critical point, wherein the effective diameter of the sensor side surface of the third lens is CA_L3S2, wherein the effective diameter of the object side surface of the fourth lens is CA_L4S1, wherein the maximum thickness among the center thicknesses of the first lens to the eighth lens is CT_Max, wherein the maximum distance among the distances between the first lens to the eighth lens is CG_Max, wherein the following mathematical expressions are satisfied: Mathematical expression: 0.5 < CA_L3S2 / CA_L4S1 < 1.5 Mathematical expression: 0 < CT_Max / CG_Max < 1.

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

3. The optical system according to claim 1, in, the optical axis distance from the center of the object side surface of the first lens to the surface of the image sensor is TTL, wherein half of the maximum diagonal length of the image sensor is Imgh, wherein the field of view of the optical system is FOV, and wherein the following mathematical expressions are satisfied: Mathematical expression: 5 < (TTL / Imgh) * n < 15 Mathematical expression: (TTL * n) < FOV, where n is the total number of lenses.

4. The optical system according to claim 1, in, when the entrance pupil diameter of the optical system is EPD and the radius of curvature of the object side surface of the first lens on the optical axis is L1R1, wherein the following mathematical expression is satisfied: 1 < EPD / L1R1 < 2.

5. The optical system according to any one of claims 1 to 4, in, the following mathematical expressions are satisfied: Mathematical expression: Imgh < TTL Mathematical expression: 50 < TTL * Imgh < 90 (The optical axis distance from the center of the object side surface of the first lens to the surface of the image sensor is TTL, and half of the maximum diagonal length of the image sensor is Imgh).

6. The optical system according to any one of claims 1 to 4, in, the normal line perpendicular to the tangent passing through any point on the sensor side surface of the eighth lens has a maximum first angle with respect to the optical axis, wherein the first angle satisfies the range of 20 degrees to 40 degrees.

7. The optical system according to claim 6, in, the normal line perpendicular to the tangent passing through any point on the object side surface of the eighth lens has a maximum second angle with respect to the optical axis, Wherein, the difference between the first angle and the second angle is 10 degrees or less.

8. The optical system according to claim 6, in, a normal line perpendicular to a tangent line passing through any point on the sensor-side surface of the seventh lens has a maximum third angle with respect to the optical axis, Wherein, the difference between the first angle and the third angle is 10 degrees or less.

9. The optical system according to claim 6, in, A normal line perpendicular to a tangent line passing through any point on the object-side surface of the seventh lens has a maximum fourth angle with respect to the optical axis, Wherein, the difference between the first angle and the fourth angle is 10 degrees or less.

10. The optical system according to any one of claims 1 to 4, in, The second lens, the third lens, and the seventh lens have a meniscus shape that is convex toward the object side on the optical axis.

11. An optical system according to any one of claims 1 to 4, in, The maximum value of the effective diameter of the object-side surface and the sensor-side surface of each of the first to eighth lenses is CA_Max, Among them, 1 / 2 of the maximum diagonal length of the image sensor is Imgh, Among them, the following mathematical formula is satisfied: 0.1 <CA_max / (2*ImgH)<1。 12. An optical system according to any one of claims 1 to 4, in, Satisfies the following mathematical formula: (v3*n3)<(v1*n1) (v1 is the Abbe number of the first lens, v3 is the Abbe number of the third lens, n1 is the refractive index of the first lens, and n3 is the refractive index of the third lens).

13. An optical system comprising: A first lens group disposed on the object side includes a plurality of lenses; A second lens group disposed on the sensor side of the first lens group has a plurality of lenses; as well as an aperture stop disposed around the object side surface of any one of the lenses of the first lens group, wherein each lens of the first lens group has a meniscus shape convex toward the object side on the optical axis, wherein the last n-th lens and the n-1-th lens in the lenses of the second lens group have a meniscus shape convex toward the object side on the optical axis, Wherein, the first lens group has positive refractive power, wherein the second lens group has negative refractive power, The number of lenses in the second lens group is greater than the number of lenses in the first lens group. Among them, the following mathematical formula is satisfied: 40<(FOV*TTL) / n<150 (TTL is the optical axis distance from the center of the object-side surface of the first lens to the surface of the image sensor, n is the total number of lenses, and FOV is the field of view).

14. The optical system according to claim 13, in, The effective diameters of the lenses of the first lens group gradually decrease from the object side toward the sensor side, and The effective diameter of the lens of the second lens group gradually increases from the lens surface closest to the first lens group toward the image sensor.

15. The optical system according to claim 12, in, The focal length of the first lens group is F13, Wherein, the focal length of the second lens group is F48, Among them, the following mathematical formula is satisfied: 1<|F48 / F13|<4 (where F48<0).

16. An optical system according to any one of claims 13 to 15, in, The first lens group includes first to third lenses, Wherein, the second lens group includes the fourth lens to the eighth lens, Wherein, the aperture stop is arranged around the object side surface of the second lens, Among them, the following mathematical formula is satisfied: CT6+CT7+CT8 <CG7 (CT6 is the center thickness of the sixth lens, CT7 is the center thickness of the seventh lens, CT8 is the center thickness of the eighth lens, and CG7 is the center distance between the seventh lens and the eighth lens).

17. The optical system according to claim 16, in, The object-side surface and the sensor-side surface of the seventh lens have a critical point, Wherein, the object side surface and the sensor side surface of the eighth lens have a critical point.

18. The optical system according to claim 16, in, The difference between the angle between the optical axis and the normal to the tangent line passing through any point of the object-side surface of the seventh lens and the angle between the optical axis and the normal to the tangent line passing through any point of the object-side surface of the eighth lens is 10 degrees or less.

19. The optical system according to claim 16, in, An angle between the optical axis and a normal line perpendicular to a tangent line passing through any point of the sensor-side surface of the seventh lens and an angle between the optical axis and a normal line perpendicular to a tangent line passing through any point of the sensor-side surface of the eighth lens are 10 degrees or less.

20. The optical system according to claim 16, in, Satisfies the following mathematical formula: 100<|L5R2 / CT5|<300 (L5R2 is the curvature radius of the fifth lens on the optical axis, and CT5 is the center thickness of the fifth lens).

21. The optical system according to claim 16, in, Satisfies the following mathematical formula: 0 <CT6 / CG7<2, 2 <CG6 / CT6<9, 1 <CG7 / CT7<5 (CT6 is the center thickness of the sixth lens, CT7 is the center thickness of the seventh lens, CG6 is the center distance between the sixth lens and the seventh lens, and CG7 is the center distance between the seventh lens and the eighth lens).

22. An optical system according to any one of claims 13 to 15, in, The sum ΣCT of the center thicknesses of the lenses of the first lens group and the second lens group and the sum ΣCG of the distances between two adjacent lenses satisfy the following mathematical formula: 0<∑CT / ∑CG<1.

23. An optical system comprising: A first lens group includes a plurality of lenses, wherein effective radii of the plurality of lenses gradually decrease from the object side to the sensor side; A second lens group is disposed on the sensor side of the first lens group and has a plurality of lenses, the effective radius of the plurality of lenses gradually increasing from the lens closer to the first lens group toward the sensor side; as well as an aperture stop disposed around the object side surface of any one lens of the first lens group, The quadratic function that approximates the curve passing from the end of the effective area of ​​the lens closest to the object side to the end of the effective area of ​​the last lens closest to the image sensor satisfies the following function: y=0.042x 2 -0.4459x+k1 (k1 is a coefficient for setting the position in the y-axis direction, and satisfies 2.7±0.2).

24. A camera module, comprising: An image sensor disposed on a sensor side of the plurality of lenses; as well as an optical filter disposed between the image sensor and the last lens, wherein the optical system comprises an optical system according to claim 1 or 14, Among them, the following mathematical formula is satisfied: 0.5 <F / TTL<1.5 0.5 <TTL / ImgH<3 4≤Imgh <TTL (F is the total focal length, TTL is the distance from the center of the object side surface of the lens closest to the object side on the optical axis to the image surface of the image sensor, and Imgh is 1 / 2 of the maximum diagonal length of the image sensor).

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