Optical system and image pickup device module including the same

Abstract

An optical system disclosed in an embodiment of the present invention comprises: first to eighth lenses arranged along an optical axis (OA) in a direction from an object side to a sensor side, wherein: the first lens has a positive (+) refractive power on the OA and has a convex object-side surface; the refractive index (n1) of the first lens and the refractive index (n2) of the second lens satisfy a mathematical formula 0lt; n1 / n2lt; 1; among the first to eighth lenses, the number of meniscus-shaped lenses protruding toward the object side on the OA is five or more; each of an object-side surface and a sensor-side surface of the sixth lens has a critical point; each of an object-side surface and a sensor-side surface of the seventh lens has a critical point; and a critical point on the sensor-side surface of the seventh lens may be positioned further outward from the OA than any one of the critical points on the object-side surface or the sensor-side surface of the sixth lens.

Description

Technical Field

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

[0002] The camera module captures an object and stores the object as an image or video, and is installed in various applications. In particular, the camera module is produced in a very small size and is applied not only to portable devices such as smart phones, tablet PCs, and laptop computers but also to drones and vehicles to provide various functions.

[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 autofocus (AF) function of aligning the focal length of the lens by automatically adjusting the distance between the image sensor and the imaging lens, and may perform a zooming function of zooming up or zooming out by increasing or decreasing the magnification of a remote object via a zoom lens. In addition, the camera module uses an image stabilization (IS) technology to correct or prevent image jitter caused by an unstable fixture or camera movement caused by user movement.

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

[0005] However, when multiple lenses are included, it is difficult to obtain excellent optical properties and aberration properties. In addition, when multiple lenses are included, the overall length, height, etc. may increase due to the thickness, spacing, size, etc. of the multiple lenses, thereby increasing the overall size of the module including the multiple lenses.

[0006] In addition, the size of image sensors is increasing to achieve high resolution and high definition. However, when the size of image sensors increases, the TTL (Total track length) of an optical system including a plurality of lenses also increases, thereby increasing the thickness of a mobile terminal and a camera device including the optical system. Therefore, a new optical system capable of solving the above problems is required. Summary of the Invention

[0007] Technical Problem

[0008] Embodiments of the present invention provide an optical system having improved optical properties. Embodiments provide an optical system having excellent optical performance at both the central portion and the peripheral portion of the field of view. Embodiments provide an optical system capable of having a thin structure.

[0009] Technical Solution

[0010] An optical system according to an embodiment of the present invention includes: a first lens to an eighth lens 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 convex object-side surface, and in the case of the refractive index (n1) of the first lens and the refractive index (n2) of the second lens, the following formula is satisfied: 0 < n1 / n2 < 1. Among the first lens to the eighth lens, the number of lenses having a meniscus shape convex toward the object side on the optical axis (OA) is five or more. Each of the object-side surface and the sensor-side surface of the sixth lens has a critical point. Each of the object-side surface and the sensor-side surface of the seventh lens has a critical point, and the critical point of the sensor-side surface of the seventh lens can be disposed more outside based on the optical axis than the critical points of the object-side surface and the sensor-side surface of the sixth lens.

[0011] According to an embodiment of the present invention, the object-side surface of the eighth lens is provided without a critical point, the sensor-side surface of the eighth lens has a critical point, and the critical point of the eighth lens can be disposed closer to the optical axis than the critical points of the object-side surface and the sensor-side surface of the sixth lens.

[0012] According to an embodiment of the present invention, the refractive index of the first lens may satisfy: 1.50 < n1 < 1.6, and the refractive index of the second lens may satisfy: 1.65 < n2.

[0013] According to an embodiment of the present invention, the first lens, the second lens, the third lens, the fifth lens, and the sixth lens may have a meniscus shape convex toward the object side on the optical axis. The seventh lens may have a meniscus shape convex toward the object side on the optical axis.

[0014] According to an embodiment of the present invention, the maximum effective diameter (CA_max) of the object-side surface and the sensor-side surface of the first lens to the eighth lens satisfies the following formula: 0.1 < CA_max / (2*ImgH) < 1, and ImgH is 1 / 2 of the maximum diagonal length of the image sensor.

[0015] According to an embodiment of the present invention, among the object-side surfaces and the sensor-side surfaces of the first lens to the eighth lens, the sensor-side surface of the eighth lens has the maximum effective diameter (CA_max), and the following formula can be satisfied: 0.5 < TTL / CA_max < 2, and TTL can be the optical axis distance from the object-side surface of the first lens to the image surface of the image sensor.

[0016] According to an embodiment of the present invention, the focal length (F1) of the first lens and the total focal length (F) can satisfy the following formula: 0 < F1 / F < 3. The focal length (F1) of the first lens and the focal length (F2) of the second lens can satisfy the following formula: -1 < F1 / F2 < 0.

[0017] According to an embodiment of the present invention, the central thickness (CT6) of the sixth lens and the central thickness (CT7) of the seventh lens can satisfy the formula: 0 < CT6 / CT7 < 1.

[0018] According to an embodiment of the present invention, the effective diameter of the object-side surface of the first lens is CA_L1S1, the effective diameter of the object-side of the third lens is CA_L3S1, and the effective diameter of the sensor-side of the eighth lens is CA_L8S2, and the following formula can be satisfied: 1 < CA_L1S1 / CA_L3S1 < 2 and 1 < CA_L8S2 / CA_L1S1 < 5.

[0019] The optical system according to an embodiment of the present invention includes: the first lens to the third lens disposed on the object side; the fourth lens to the eighth lens disposed on the sensor side; and an aperture stop disposed around the sensor-side surface of any one of the first lens to the third lens, wherein the sensor-side surface of the third lens faces the object-side surface of the fourth lens, and the sensor-side surface of the third lens has a concave shape on the optical axis, the object-side surface of the fourth lens has a convex shape on the optical axis, and the first lens to the third lens have a meniscus shape protruding toward the object side on the optical axis, the effective diameters of the object-side surfaces and the sensor-side surfaces of the first lens to the third lens gradually decrease from the object side toward the sensor side, and the effective diameters of the object-side surfaces and the sensor-side surfaces of the fourth lens to the eighth lens can gradually increase from the object side to the sensor side.

[0020] According to an embodiment of the present invention, when the combined focal length from the first lens to the third lens is F13 and the combined focal length from the fourth lens to the eighth lens is F48, the following formula can be satisfied: 1 < |F48 / F13| < 4. The aperture stop is disposed around the sensor-side surface of the second lens, the combined focal length of the first lens to the second lens is F12, and the combined focal length of the third lens to the eighth lens is F38, and the following formula can be satisfied: F12 > F13, and |F38| > |F48|.

[0021] According to an embodiment of the present invention, the object-side surface and the sensor-side surface of the sixth lens have critical points, the sensor-side surface of the seventh lens has a critical point, the distance from the optical axis to the critical point of the object-side surface of the sixth lens is Inf61, the distance from the optical axis to the critical point of the sensor-side surface of the sixth lens is Inf62, the distance from the optical axis to the critical point of the sensor-side surface of the seventh lens is Inf72, and the following formula can be satisfied: 0 < Inf61 / Inf62 < 1, 0 < Inf61 / Inf72 < 1, 0 < Inf62 / Inf72 < 1.

[0022] According to an embodiment of the present invention, the radius of curvature of the object-side surface of the first lens is L1R1, the radius of curvature of the sensor-side surface of the first lens is L1R2, the radius of curvature of the object-side surface of the second lens is L2R1, the radius of curvature of the sensor-side surface of the second lens is L2R2, and the following formula can be satisfied: 0 < L1R1 / L1R2 < 1 and 0 < L2R2 / L2R1 < 1.

[0023] According to an embodiment of the present invention, the object-side surface and the sensor-side surface of the eighth lens have an aspherical shape on the optical axis, and the distance between the sensor-side surface of the eighth lens and the image sensor can satisfy the following formula: 1 < BFL / L8S2_max_sag to Sensor < 2, where BFL is the distance from the center of the sensor-side surface of the eighth lens to the optical axis of the image sensor, and L8S2_max_sag to Sensor is the distance from the maximum sag value of the sensor-side surface of the eighth lens to the image sensor.

[0024] According to an embodiment of the present invention, the center thickness CT1 of the first lens, the center thickness CT2 of the second lens, and the center thickness CT7 of the seventh lens can satisfy the following formula: 2 < CT1 / CT2 < 4 and 0 < CT1 / CT7 < 2.

[0025] According to an embodiment of the present invention, the sum of the center thicknesses (∑CT) of the first lens to the eighth lens and the sum of the distances (∑CG) between two adjacent lenses can satisfy the following formula: 1 < ∑CT / ∑CG < 1.8.

[0026] The imaging device module according to an embodiment of the present invention includes: an image sensor; and an optical filter disposed between the image sensor and the last lens, wherein the optical system includes the optical system disclosed above and satisfies the following formula: 0.5 < F / TTL < 1.5 and 0.5 < TTL / ImgH < 3, where F is the average value of the total focal lengths in two directions orthogonal to the optical axis of the optical system, TTL (Total tracklength) is the distance on the optical axis from the center of the object side surface of the first lens to the image surface of the image sensor, and ImgH is 1 / 2 of the maximum diagonal length of the image sensor.

[0027] Advantageous Effects

[0028] The optical system and the imaging device module according to the embodiment can have improved optical properties. Specifically, the optical system can have improved aberration characteristics and resolution according to the surface shape, refractive power, thicknesses of multiple lenses, and distances between adjacent lenses among the multiple lenses.

[0029] The optical system and the imaging device module according to the embodiment can have improved distortion and aberration characteristics, and can have good optical performance at the central part and the peripheral part of the field of view (FOV). The optical system according to the embodiment can have improved optical characteristics and a smaller total track length TTL (Total tracklength), such that the optical system and the imaging device module including the optical system can be arranged in a thin and compact structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 is a configuration diagram of an optical system and an imaging device module according to an embodiment of the present invention.

[0031] Figure 2 is a diagram showing Figure 1 the relationship between the image sensor, the n-th lens, and the (n - 1)-th lens of the optical system.

[0032] Figure 3 is a diagram showing Figure 1 the lens data of the first embodiment of the optical system having

[0033] Figure 4 is an example of the aspherical surface coefficients of the lens according to the first embodiment of the present invention.

[0034] Figure 5 is a table showing the thicknesses of the lenses in the optical system according to the first embodiment of the present invention in a direction orthogonal to the optical axis and the distances between the lenses.

[0035] 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 first embodiment of the present invention.

[0036] Figure 7 : is a graph showing the light aberration characteristics of the optical system according to the first embodiment of the present invention.

[0037] Figure 8 : is a graph showing aberration characteristics of the optical system according to the first embodiment of the present invention.

[0038] Fig. 9 It is shown that according to Figure 1 A table of lens data of a second embodiment of the optical system.

[0039] Fig.10 ⊥ ...

[0040] Fig.11 This is a table showing the thickness of the lenses in the direction perpendicular to the optical axis and the distances between the lenses in the optical system according to the second embodiment of the present invention.

[0041] Fig.12 : 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 second embodiment of the present invention.

[0042] Fig.13 : is a graph showing the light aberration characteristics of the optical system according to the second embodiment of the present invention.

[0043] Fig.14 : is a graph showing aberration characteristics of the optical system according to the second embodiment of the present invention.

[0044] Fig.15 is a graph 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.

[0045] Fig.16 is a diagram showing that a camera module according to an embodiment is applied to a mobile terminal. DETAILED DESCRIPTION

[0046] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The technical spirit of the present invention is not limited to some embodiments to be described, but can be implemented in various other forms, and one or more of the components can be selectively combined and replaced within the scope of the technical spirit of the present invention for use. 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 with the meanings commonly understood by ordinary technicians in the field to which the present invention belongs, and commonly used terms (such as, terms defined in dictionaries) should be able to interpret their meanings in consideration of the contextual meaning of the relevant technology.

[0047] The terms used in the embodiments of the present invention are used to illustrate the embodiments, and are not intended to limit the present invention. In this specification, the singular form may also include the plural form, unless otherwise specifically stated in the phrase, in the case of describing at least one (or one or more) of A and (and) B, C, it may include one or more of all combinations that 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. Such terms are only to distinguish the components from other components, rather than to determine the properties, order or process of the corresponding constituent elements by the terms. And when describing a component "connected", "coupled" or "engaged" to another component, the description may include not only direct connection, coupling or engagement to another component, but also "connection", "coupling" or "engagement" between the component and other components. In addition, in the case of being described as being formed or arranged "above (up)" or "below (below)" of each component, the description may include not only the situation where the two components are in direct contact with each other, but also the situation where one or more other components are formed or arranged between the two components. In addition, when expressed as “above” or “below”, it can refer to a downward direction as well as an upward direction with respect to one element.

[0048] 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 table of lens data may mean the value on the optical axis, and the unit is mm. The vertical direction may mean the direction perpendicular to the optical axis, and the end of the lens or lens surface may mean the end or edge of the effective area of ​​the lens through which the incident light passes. Depending on the measurement method, the effective diameter on 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 falling from the optical axis (OA) is almost zero. In the following, the concave shape or convex shape of the lens surface will be described as the optical axis, and the paraxial area may also be included.

[0049] Figure 1 The diagrams show an optical system (1000) and an image pickup device module having the optical system (1000) according to the first and second embodiments of the present invention.

[0050] Reference Figure 1 , the optical system (1000) or the camera module may include a plurality of lens groups (LG1, LG2). In detail, each of the plurality of lens groups (LG1, 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 on 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), and may be, for example, more than 1 times and less than 2 times the number of lenses of the first lens group LG1.

[0051] The first lens group (LG1) may include two or more lenses. The first lens group (LG1) may include three or fewer lenses. For example, the first lens group (LG1) may include three lenses. The second lens group (LG2) may include three or more lenses. The second lens group (LG2) may include more lenses than the number of lenses of the first lens group (LG1), for example, 7 or fewer lenses or 6 or fewer lenses. The number of lenses of the second lens group (LG2) may be three or more than the number of lenses of the first lens group (LG1). For example, the second lens group (LG2) may include 5 lenses.

[0052] In the optical system (1000), the total track length TTL (Total track length) can be less than 70% of the diagonal length of the image sensor (300), for example, in the range of 40% to 69% or 50% to 60%. TTL is the distance from the object side surface of the first lens (101) closest to the object side to the image surface of the image sensor (300) on the optical axis (OA), and 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 of the image sensor (300). Therefore, a slim optical system and a camera module having the slim optical system can be provided. The total number of lenses of the first lens group and the second lens group (LG1, LG2) is 7 to 9.

[0053] 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) may have different focal lengths and opposite refractive powers, thereby providing good optical performance at the central and peripheral portions of the FOV. The refractive power is the reciprocal of the focal length.

[0054] When expressed as an absolute value, 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 1.4 times or greater, for example, in the range of 1.4 times to 2 times, of the absolute value of the focal length (F_LG1) of the first lens group (LG1). Therefore, the optical system (1000) according to the embodiment may have improved aberration control characteristics such as chromatic aberration and distortion aberration by controlling the refractive power and focal length of each lens group, and have good optical performance in the central portion and the peripheral portion of the FOV.

[0055] 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 a separation distance on the optical axis (OA), and may be an optical axis distance between a sensor-side surface of a lens closest to the sensor among the lenses in the first lens group (LG1) and an object-side surface of a lens closest to the object among the lenses in 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 a center thickness of a lens that is the last lens among the lenses of the first lens group (LG1) and a center thickness of a lens that is the first lens 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 less than the optical axis distance of the first lens group (LG1) and be 20% or less of the optical axis distance of the first lens group (LG1), and may be, for example, in the range of 5% to 15% or 5% to 12% of the optical axis distance of the first lens group (LG1). Here, the optical axis distance of the first lens group (LG1) is the optical axis distance between the object side surface of the lens closest to the object side and the sensor side surface of the lens closest to the sensor side of the first lens group (LG1).

[0056] The optical axis distance between the first lens group (LG1) and the second lens group (LG2) may be 10% or less of the optical axis distance of the second lens group (LG2), for example, in the range of 2% to 10% or 2% to 6%. The optical axis distance of the second lens group (LG2) is the optical axis distance between the object-side surface of the lens closest to the object side of the second lens group (LG2) and the sensor-side surface of the lens closest to the sensor side.

[0057] 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 effective diameter is an 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 field of view (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).

[0058] The optical system (1000) may include 10 or less lenses or 9 or less lenses. The first lens group (LG1) refracts light incident through the object side to converge, and the second lens group (LG2) may refract light emitted through the first lens group (LG1) to diffuse to the peripheral portion of the image sensor (300).

[0059] 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 greater than the number of lenses having a negative (-) refractive power. In the first lens group (LG1), the number of lenses having a positive (+) refractive power may be greater than the number of lenses having a negative (-) refractive power. In the second lens group (LG2), the number of lenses having a positive (+) refractive power may be less than the number of lenses having a negative (-) refractive power.

[0060] Each lens of the plurality of lenses (100) may include an effective area and an ineffective area. The effective area may be an area through which light incident on each lens of the lenses (100) passes. That is, the effective area may be an effective area or an effective diameter area that realizes optical properties by refracting the incident light. The ineffective area may be arranged around the effective area. The ineffective area may be an area into which effective light from the plurality of lenses (100) is not incident. That is, the ineffective area may be an area that is not related to optical properties. In addition, the end of the ineffective area may be an area fixed to a lens barrel (not shown) that accommodates the lens.

[0061] 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 2 mm, for example, greater than 4 mm and less than 12 mm. Preferably, the ImgH of the image sensor (300) may be less than TTL.

[0062] 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 the 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).

[0063] 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 light of a different wavelength band. In the case where 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 transmit visible light and reflect infrared light. As another example, a cover glass may be further disposed between the optical filter (500) and the image sensor (300).

[0064] The optical system (1000) according to an embodiment may include an aperture stop (ST). The aperture stop (ST) may control the amount of light incident on the optical system (1000). The aperture stop (ST) may be disposed around at least one lens of the first lens group (LG1). For example, the aperture stop (ST) may be disposed around an object side surface or a 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 in the first lens group (LG1). Alternatively, at least one lens selected from among the plurality of lenses (100) may be used as an aperture stop. In detail, an object side surface or a sensor side surface of a lens selected from among the lenses of the first lens group (LG1) may be used as an aperture stop for adjusting the amount of light.

[0065] The straight-line distance from the aperture stop (ST) to the sensor-side surface of the n-th lens can be less than the optical axis distance from the object-side surface of the first lens (101) to the sensor-side surface of the n-th lens. When SD is the optical axis distance from the aperture stop (ST) to the sensor-side surface of the n-th lens, SD < EFL can be satisfied. Additionally, SD < ImgH can be satisfied. EFL is the effective focal length of the entire optical system and can be defined as F. EFL and ImgH can be the same as or different from each other and can have a difference of 2 mm or less. The FOV of the optical system (1000) can 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) can be greater than 1 and less than 10, for example, 1.1 ≤ F# ≤ 5. Additionally, F# can be less than the entrance pupil diameter (EPD). Therefore, the optical system (1000) has a thin and compact size, can control incident light, and can have improved optical characteristics within the FOV.

[0066] The effective diameter of the lens gradually decreases from the object-side lens to the lens surface (e.g., the fourth surface) where the aperture stop is provided, and can gradually increase from the effective diameter of the lens surface (e.g., the fifth surface) located on the sensor side rather than the aperture stop to the effective diameter of the lens surface of the last lens.

[0067] The optical system (1000) according to an embodiment may further include a reflection member (not shown) for changing the path of light. The reflection member can be implemented as a prism that reflects the incident light of the first lens group (LG1) toward the lens. Hereinafter, the optical system according to the embodiment will be described in detail.

[0068] Figure 1 is a configuration diagram of an optical system and an imaging device module according to an embodiment of the present invention, and Figure 2 shows Figure 1 an explanatory diagram of the relationship between the image sensor, the n-th lens, and the n-1-th lens of the optical system.

[0069] Referring to Figure 1 and Figure 2 According to the first embodiment and the second embodiment, the optical system (1000) includes a lens unit (100) having a plurality of lenses, and the lens unit (100) includes a first lens (101) to an eighth lens (108). The first lens to the eighth lens (101 to 108) can be sequentially aligned on the optical axis (OA) of the optical system (1000). Light corresponding to object information can pass through the first lens (101) to the eighth lens (108) and the optical filter (500) and be incident on the image sensor (300).

[0070] The first lens group (LG1) may include first to third lenses (101 to 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 optical axis distance between the first lens group (LG1) and the second lens group (LG2). Among 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, and may satisfy: n-2. n is the total number of lenses, and may be, for example, 8.

[0071] The first lens (101) may have a negative (-) refractive power or a positive (+) refractive power on the optical axis (OA), and may preferably have a 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. 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. The aspherical coefficients of the first surface and the second surface (S1, S2) are as follows Figure 4 and Fig.10 In the arrangement shown, L1 is the first lens (101), L1S1 is the first surface, and L1S2 is the second surface.

[0072] The second lens (102) may have a positive (+) refractive power or a 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. The second lens (102) may include a third surface (S3) defined as an object side surface and a fourth surface (S4) defined as a sensor side surface. On the optical axis (OA), the third surface (S3) may have a convex shape, and the fourth surface (S4) may have a concave shape. That is, the second lens (102) may have a meniscus shape that 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 and the fourth surface (S3, S4) are as follows: Figure 4 and Fig.10 In the arrangement shown, L2 is the second lens (102), L2S1 is the third surface, and L2S2 is the fourth surface.

[0073] The third lens (103) may have a positive (+) refractive power or a negative (-) refractive power on the optical axis (OA), and may preferably have a 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. 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 convex toward the object side on the optical axis (OA). Alternatively, on the optical axis (OA), the fifth surface (S5) may have a convex shape, and the sixth surface (S6) may have a convex shape. 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 aspheric coefficients of the fifth and sixth surfaces (S5, S6) are as follows: Figure 4 and Fig.10 In the arrangement shown, L3 is the third lens (103), L3S1 is the fifth surface, and L3S2 is the sixth surface.

[0074] The first lens group (LG1) may include first to third lenses (101, 102, 103). Among the first to third lenses (101, 102, 103), the first lens (101) may be the thickest, and the second lens (102) may be the thinnest in terms of thickness on the optical axis (OA), i.e., the center thickness of the lens. Therefore, the optical system (1000) may control incident light and may have improved aberration characteristics and resolution. Among the first to third lenses (101, 102, 103), the effective diameter CA (Clear aperture) of the third lens may be the smallest, and the effective diameter of the first lens (101) may be the largest. In detail, among the first to third lenses (101, 102, 103), the effective radius r11 (Semi-aperture) of the first surface (S1) may be the largest, and the effective radius of the sixth surface (S6) of the third lens (103) may be the smallest. The effective diameter of the second lens (102) may be smaller than the effective diameter of the first lens (101) and larger than the effective diameter of the third lens (103). The effective diameter of the third lens (103) may be the smallest among all lenses of the optical system (1000). The effective diameter is an average value of the effective diameter of the object side surface of each lens and the effective diameter of the sensor side surface of each lens. Therefore, the optical system (1000) may have improved chromatic aberration control characteristics, and the vignetting characteristics of the optical system (1000) may be improved by controlling incident light.

[0075] The refractive index of the second lens (102) may be greater than the refractive index of at least one or both of the first lens and the third lens (101, 103). The refractive index of the second lens (102) may be greater than 1.6, for example, 1.65 or greater, and the refractive index of the first lens and the third lens (101, 103) may be less than 1.6. The second lens (102) may have an Abbe number smaller than the Abbe number of at least one or both of the first lens and the third lens (101, 103). For example, the Abbe number of the second lens (102) may be 20 or more smaller than the Abbe number of the first lens and the third lens (101, 103), and may be, for example, 30 smaller. In detail, the Abbe number of the first lens and the third lens (101, 103) may be 30 or more greater than the Abbe number of the second lens (102). Therefore, the optical system (1000) may have improved chromatic aberration control characteristics.

[0076] When the radius of curvature on the optical axis (OA) is expressed as an absolute value, the radius of curvature of the sixth surface (S6) of the third lens (103) may be the largest among the first to third lenses (101, 102, 103), and may be, for example, 10 mm or more. The radius of curvature of the first surface (S1) of the first lens (101) may be the smallest, and may be 7 mm or less. In the first lens group (LG1), the difference between the lens surface having the largest radius of curvature and the lens surface having the smallest radius of curvature may be 5 times or more. The average radius of curvature of the first to sixth surfaces (S1 to S6) may be 15 mm or less, for example, in the range of 5 mm to 15 mm. Each of the first to third lenses (101 to 103) may have a meniscus shape convex toward the object side.

[0077] The fourth lens (104) may have a positive (+) refractive power or a negative (-) refractive power on the optical axis (OA). The fourth lens (104) may have a negative (-) 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. 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 concave shape. That is, the fourth lens (104) may have a concave shape on both sides of the optical axis (OA). Alternatively, the seventh surface (S7) may have a concave shape on the optical axis (OA), and the eighth surface (S8) may have a convex shape on the optical axis (OA). That is, the fourth lens (104) may have a meniscus shape convex from the optical axis (OA) toward the sensor. Alternatively, the fourth lens (104) may have a meniscus shape that is convex toward the object side on the optical axis (OA). 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. The aspherical coefficients of the seventh surface and the eighth surface (S7, S8) are as follows: Figure 4 and Fig.10 In the arrangement shown, L4 is the fourth lens (104), L4S1 is the seventh surface, and L4S2 is the eighth surface.

[0078] When expressed as an absolute value, the radius of curvature of the seventh surface (S7) of the fourth lens (104) may be the largest in the optical system (1000). When expressed as an absolute value, the focal length of the fourth lens (104) may be the largest in the optical system (1000). The refractive index of the fourth lens (104) may be greater than the refractive indexes of the first lens and the third lens (101, 103). The Abbe number of the fourth lens (104) may be less than the Abbe number of the first lens and the third lens (101, 103). Therefore, the optical system (1000) may have improved chromatic aberration control characteristics.

[0079] The fifth lens (105) may have a positive (+) refractive power or a negative (-) refractive power on the optical axis (OA). The fifth lens (105) may have a positive (+) 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. When expressing an absolute value, the focal length of the fifth lens (105) may be smaller than the focal length of the fourth lens (104), and may satisfy, for example: 20<|F5-F4|<150. The fifth lens (105) may include a ninth surface (S9) defined as an object side surface and a tenth surface (S10) defined as a sensor side surface. The ninth surface (S9) may have a convex shape on the optical axis (OA), and the tenth surface (S10) may have a concave shape on the optical axis (OA). That is, the fifth lens (105) may have a meniscus shape convex toward the object side on the optical axis (OA). The ninth surface and the tenth surface (S9, S10) of the fifth lens (105) can be arranged to have no critical point from the optical axis (OA) to the end of the effective area. In addition, when expressed as an absolute value, the average value of the radius of curvature of the ninth surface and the tenth surface (S9, S10) of the fifth lens (105) is smaller than the radius of curvature of the eighth surface (S8) of the fourth lens (104), and can be 100 mm or less, for example, 50 mm or less. At least one of the ninth surface (S9) or the tenth surface (S10) can be an aspherical surface. For example, both the ninth surface (S9) and the tenth surface (S10) can be aspherical surfaces. The aspherical coefficients of the ninth surface and the tenth surface (S9, S10) are as follows Figure 4 and Fig.10 In the arrangement shown, L5 is the fifth lens (105), L5S1 is the ninth surface, and L5S2 is the tenth surface.

[0080] The sixth lens (106) may have a positive (+) refractive power or a 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. The sixth lens (106) may include an eleventh surface (S11) defined as an object side surface and a twelfth surface (S12) defined as a sensor side surface. The eleventh surface (S11) may have a convex shape on the optical axis (OA), and the twelfth surface (S12) may have a concave shape on the optical axis (OA). That is, the sixth lens (106) may have a meniscus shape convex toward the object side on the optical axis (OA). Alternatively, the eleventh surface (S11) may have a concave shape on the optical axis (OA), and the twelfth surface (S12) may have a convex shape or a concave shape on the optical axis (OA). That is, the sixth lens (106) may have a meniscus shape that is convex toward the sensor side, or a concave shape on both sides.

[0081] When the radius of curvature on the optical axis (OA) is expressed as an absolute value, the average value of the radius of curvature of the eleventh surface and the twelfth surface (S12) of the sixth lens (106) may be greater than the average value of the radius of curvature of the seventh lens (107) and the average value of the radius of curvature of the eighth lens (108). The average value of the radius of curvature of the eleventh surface and the twelfth surface (S12) of the sixth lens (106) may be less than the average value of the radius of curvature of the fifth lens (105). The refractive index of the sixth lens (106) is 1.55 or more, which is less than the refractive index of the second lens (102), and may be greater than the refractive indexes of the seventh lens and the eighth lens (107, 108).

[0082] When expressed as an absolute value, the focal length of the sixth lens (106) may be greater than the focal length of the fifth lens (105) and less than the focal length of the seventh lens (107). 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. The aspherical coefficients of the eleventh surface and the twelfth surface (S11, S12) are as follows: Figure 4 and Fig.10 In the arrangement shown, L6 is the sixth lens (106), L6S1 is the eleventh surface, and L6S2 is the twelfth surface.

[0083] From the optical axis (OA) to the end of the effective radius, the eleventh surface (S11) may have at least one critical point, and the twelfth surface (S12) may have at least one critical point. Here, when the distance from the optical axis (OA) to the critical point of the eleventh surface (S11) of the sixth lens (106) is defined as Inf61, and the distance to the critical point of the twelfth surface (S12) is defined as Inf62, the following formula may be satisfied: 0 < Inf61 / Inf62 < 1. Additionally, it may also be satisfied that: Inf61 < Inf62, and based on the distance from the optical axis (OA) to the end of the effective region, Inf61 may be within a range of 40% or less, for example, within a range of 30% to 40%, and Inf62 may be within a range of 40% or more, for example, within a range of 40% to 50%.

[0084] The seventh lens (107) may have a positive (+) refractive power or a negative (-) refractive power on the optical axis (OA). The seventh lens (107) may have a 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. The seventh lens (107) may include a thirteenth surface (S13) defined as the object-side surface and a fourteenth surface (S14) defined as the sensor-side surface. The thirteenth surface (S13) may have a convex shape on the optical axis (OA), and the fourteenth surface (S14) may have a concave shape on the optical axis (OA). That is, the seventh lens (107) may have a meniscus shape that bulges toward the object side on the optical axis (OA). Alternatively, the thirteenth surface (S13) may have a concave shape on the optical axis (OA), or the fourteenth surface (S14) may have a convex shape on the optical axis (OA), that is, the seventh lens (107) has a concave shape on both sides of the optical axis (OA), a shape that bulges on both sides, or a meniscus shape that bulges toward the sensor on both sides.

[0085] As Figure 2As shown, at least one critical point may exist on the thirteenth surface (S13) and the fourteenth surface (S14) of the seventh lens (107) from the optical axis (OA) to the end of the effective region. The critical point (P1) of the thirteenth surface (S13) has a distance (Inf71) of 49% or less (e.g., in the range of 26% to 46% or in the range of 31% to 41%) of the effective radius (r71), where the effective radius (r71) is the distance from the optical axis (OA) to the end of the effective radius. The critical point of the fourteenth surface (S14) may be located at a distance (Inf72) of 35% or more (e.g., in the range of 35% to 55% or in the range of 40% to 50%) of the effective radius with respect to the optical axis (OA). The position of the critical point of the fourteenth surface (S14) may be farther from the optical axis (OA) than the critical point (P1) of the thirteenth surface (S13). Based on the optical axis, Inf71 < Inf72 can be satisfied. In addition, the position of Inf62 may be closer to the optical axis than the position of Inf72.

[0086] The fourteenth surface (S14) may diffuse the light incident through the thirteenth surface (S13). The critical point is the point where the sign of the slope value with respect 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 mean the point where the slope value is zero. In addition, the critical point may be the point where the slope value of the tangent line passing through the lens surface decreases as it increases, or the point where the slope value increases as it decreases. Considering the optical characteristics of the optical system (1000), the position of the critical point of the seventh lens (107) is preferably set at a position that satisfies the above range. Specifically, the position of the critical point preferably satisfies the above range to control the optical characteristics of the optical system (1000), such as chromatic aberration, distortion characteristics, aberration characteristics, and resolution. Therefore, the path of the light emitted through the lens to the image sensor (300) can be effectively controlled. Thus, the optical system (1000) according to the embodiment may have improved optical characteristics even in the central part and the peripheral part of the FOV. 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. The aspherical coefficients of the thirteenth surface and the fourteenth surface (S13, S14) are set as Figure 4 and Fig.10 shown, where L7 is the seventh lens (107), L7S1 is the thirteenth surface, and L7S2 is the fourteenth surface.

[0087] The eighth lens (108) 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 may be the last lens in the optical system (1000).

[0088] 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. The fifteenth surface (S15) may have a concave shape on the optical axis (OA), and the sixteenth surface (S16) may have a concave shape on the optical axis (OA). That is, the eighth lens (108) may have a concave shape on both sides of the optical axis (OA). Alternatively, the eighth lens (108) may have a meniscus shape convex toward the object side on the optical axis or a meniscus shape convex toward the sensor side. The fifteenth surface and the sixteenth surface (S15, S16) may be aspherical surfaces. The aspherical coefficients of the fifteenth surface and the sixteenth surface (S15, S16) are as follows Figure 4 and Fig.10 In the arrangement shown, L8 is the eighth lens (108), L8S1 is the fifteenth surface, and L8S2 is the sixteenth surface.

[0089] like Figure 2As shown, the fifteenth surface (S15) of the eighth lens (108) can be set to have no critical point from the optical axis (OA) to the end of the effective area. The sixteenth surface (S16) of the eighth lens (108) can have at least one critical point within the distance (r82) from the optical axis (OA) to the end of the effective area. The critical point (P2) of the sixteenth surface (S16) is a distance (Inf82) from the optical axis (OA) to the end of the effective radius, that is, 32% or less of the effective radius (r82), and can be, for example, in the range of 12% to 32% or in the range of 17% to 27%. The critical point (P2) of the fourteenth surface (S16) can be positioned closer to the optical axis (OA) than the critical point (P1) of the thirteenth surface (S13). Therefore, the sixteenth surface (S16) can diffuse the light incident through the fifteenth surface (S15). The positions of the critical points of the sixth lens, the seventh lens, and the eighth lens (106, 107, 108) may be located within a range of 0.8 mm to 2.5 mm or 1 mm to 2.3 mm relative to the optical axis (OA). In addition, the normal (K2) is a straight line perpendicular to the tangent (K1) passing through an arbitrary point on the sensor-side sixteenth surface (S16) of the last lens, i.e., the eighth lens (108), and forms a predetermined angle (θ1) with the optical axis (OA), and the maximum angle of the angle (θ1) may be greater than 5 degrees and less than 65 degrees, for example, within a range of 20 degrees to 50 degrees or within a range of 20 degrees to 40 degrees. Therefore, since the optical axis or paraxial region of the sixteenth surface (S16) has a minimum sag value, a slim optical system may be provided.

[0090] Among the fourth to eighth lenses (104, 105, 106, 107, 108), the lens having the largest center thickness is the seventh lens (107), and the center thickness of the seventh lens (107) may be greater than the optical axis distance between the sixth lens and the seventh lens (106, 107). In the second lens group (LG2), the lens having the smallest center thickness may be the fourth lens or the fifth lens (104, 105). Therefore, the optical system (1000) may control incident light and may have improved aberration characteristics and resolving power.

[0091] Among the fourth to eighth lenses (104, 105, 106, 107, 108), the fourth lens (104) may have the smallest effective diameter (clear aperture (CA)) among these lenses, and the eighth lens (108) may have the largest effective diameter (clear aperture: CA). In detail, in the second lens group (LG2), the effective diameter of the seventh surface (S7) of the fourth lens (104) may be the smallest, and the effective diameter of the sixteenth surface (S16) may be the largest. The effective diameter of the sixteenth surface (S16) may be the largest effective diameter in the optical system, and may be 2.2 times larger than the effective diameter of the seventh surface (S7). The effective diameter of the eighth lens (108) is the largest, so that incident light can be effectively refracted toward the image sensor (300). Therefore, the optical system (1000) can have improved chromatic aberration control characteristics, and the vignetting characteristics of the optical system (1000) can be improved by controlling incident light.

[0092] In the second lens group (LG2), the number of lenses having a refractive index greater than 1.6 may be smaller than the number of lenses having a refractive index less than 1.6. In the second lens group (LG2), the number of lenses having an Abbe number greater than 50 may be smaller than the number of lenses having an Abbe number less than 50.

[0093] Reference Figure 2 , the back focal length BFL (Back focal length) is the optical axis distance from the image sensor (300) to the last lens. That is, BFL is the optical axis distance between the image sensor (300) and the sensor-side sixteenth surface (S16) 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 (e.g., center distance) from the center of the sensor-side surface of the seventh lens (107) to the center of the object-side surface of the eighth lens (108). That is, the optical axis distance CG7 from the center of the sensor-side surface of the seventh lens (107) to the center of the object-side surface of 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 and the fourth lens (103, 104). CG7 may be smaller than the sum of the center thicknesses of the seventh lens and the eighth lens (107, 108).

[0094] The center thickness of the seventh lens (102) is the largest among the center thicknesses of the lenses, and the center distance (CG7) between the seventh lens (107) and the eighth lens (108) is the largest among the distances between the lenses. The center thickness of the second lens (102) is the smallest among the center thicknesses of the lenses, and the center distance between the first lens and the second lens (101, 102) is the smallest among the distances between the lenses. Among the lenses (101 to 108), the maximum center thickness can be 2.5 times or more of the minimum center thickness, for example, in the range of 2.5 times to 5 times. Among the plurality of lenses (100), the number of lenses having a center thickness less than 0.5 mm can be greater than the number of lenses having a center thickness of 0.5 mm or more. Therefore, the optical system (1000) can be provided with a structure having a slim thickness.

[0095] The refractive index of the sixth lens (106) may be greater than the refractive indexes of the seventh lens and the eighth lens (107, 108), and may be equal to or greater than 1.6. The sixth lens (106) may have an Abbe number smaller than the Abbe numbers of the seventh lens and the eighth lens (107, 108). For example, the Abbe number of the sixth lens (106) may be 20 or more smaller than the Abbe number of the eighth lens (108). In detail, the Abbe number of the eighth lens (108) may be 25 or more greater than the Abbe number of the sixth lens (106), for example, 50 or more. Therefore, the optical system (1000) may have improved chromatic aberration control characteristics.

[0096] Among the plurality of lens surfaces (S1 to S16), the number of surfaces having an effective radius less than 2 mm may be less than the number of surfaces having an effective radius of 2 mm or more. Describing the radius of curvature as an absolute value, the radius of curvature of the seventh surface (S7) of the fourth lens (104) among the plurality of lenses (100) may be the largest among the radii of curvature of the lens surfaces on the optical axis (OA), and the radius of curvature of the first surface (S1) of the first lens (101) may be the smallest among the radii of curvature of the lens surfaces on the optical axis (OA).

[0097] Describing the focal length as an absolute value, the focal length of the fourth lens (104) among the plurality of lenses (100) may be the largest among the lenses, and the focal lengths of the fourth lens (104) and the seventh lens (107) may be greater than or equal to 100 mm. The focal length of any one of the first lens and the eighth lens (101, 108) may be the smallest and may be 20 mm or less. The maximum focal length may be 10 times or more the minimum focal length.

[0098] The optical system (1000) according to the embodiment disclosed above can satisfy at least one or two or more of the various formulas described below. Therefore, the optical system (1000) according to the embodiment can have improved optical characteristics. For example, when the optical system (1000) satisfies at least one 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 part of the FOV but also in the peripheral part. The optical system (1000) can have improved resolution and can have a thinner and more compact structure.

[0099] Hereinafter, the center thickness of the first to eighth lenses (101 to 108) may be defined as CT1 to CT8, the edge thickness may be defined as ET1 to ET8, and the optical axis distance between two adjacent lenses may be defined as the distance between the first and second lenses to the distance between the seventh and eighth lenses, that is, CG1 to CG8, and the edge distance between two adjacent lenses may be defined as the distance between the first and second lenses to the distance between the seventh and eighth lenses, that is, EG1 to EG8. The units of thickness and distance are mm.

[0100] [Formula 1]2 <CT1 / CT2<4

[0101] In Formula 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, the above Formula 1 can satisfy: 3≤CT1 / CT2<4.

[0102] [Formula 2]1 <CT3 / ET3<2

[0103] In Formula 2, when the thickness (CT3) of the third lens (103) on the optical axis and the thickness (ET3) at the edge of the effective area of ​​the third lens (103) are satisfied, the optical system (1000) can have improved chromatic aberration control characteristics. Preferably, the above Formula 2 can satisfy: 1 <CT3 / ET3≤2。

[0104] [Formula 2-1]1 <CT1 / ET1<5

[0105] [Formula 2-2]0 <CT2 / ET2<1.5

[0106] [Formula 2-3] (CT2+CT3) <CT1

[0107] [Formula 2-4] 1≤CT4 / ET4<3

[0108] [Formula 2-5] 0.5 <CT5 / ET5<2.5

[0109] [Formula 2-6]0 <CT6 / ET6<1

[0110] [Formula 2-7]1 <CT7 / ET7<4

[0111] [Formula 2-8]1 <CT8 / ET8<3

[0112] [Formula 2-9] 0.5 <SD / TD<1

[0113] When the ratio of the center thickness to the edge thickness of the second lens to the eighth lens (102 to 108) in Formulas 2-1 to 2-8 is satisfied, the optical system (1000) can have improved chromatic aberration control characteristics. SD is the optical axis distance from the aperture stop to the sensor-side sixteenth surface (S16) of the eighth lens (108), and TD is the 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 can be arranged around the sensor-side surface of the second lens (102). When the optical system (1000) according to the embodiment satisfies Formula 2-9, the chromatic aberration of the optical system (1000) can be improved.

[0114] [Formula 2-10] 1<|F_LG2 / F_LG1|<10

[0115] 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 Formula 2-10, the chromatic aberration of the optical system (1000) can be improved. That is, when the value of Formula 2-10 is close to 1, the distortion aberration can be reduced. The value of Formula 2-10 can satisfy: 1<|F_LG2 / F_LG1|<3.

[0116] [Formula 3] <ET8 / CT8<2

[0117] In Formula 3, when the thickness (CT8) on the optical axis and the thickness (ET8) at the edge of the eighth lens (108) are satisfied, the optical system (1000) may have improved chromatic aberration control characteristics. Formula 3 may satisfy: 0.3≤ET8 / CT8<1.

[0118] [Equation 4] 1.6 <n2

[0119] In Formula 4, n2 means a refractive index of the second lens (102) at the d-line. When the optical system (1000) according to the embodiment satisfies Formula 4, the optical system (1000) can improve chromatic aberration characteristics.

[0120] [Formula 4-1]

[0121] 1.50 <n1<1.6

[0122] 1.50 <n8<1.6

[0123] In Formula 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 Formula 4-1, the influence on the TTL of the optical system (1000) can be suppressed.

[0124] [Formula 4-2]

[0125] 1.60 <n4

[0126] 1.60≤n6

[0127] In Formula 4-2, n4 is the refractive index of the fourth lens (104) at the d-line, and n6 is the refractive index of the sixth lens (106) at the d-line. When the optical system (1000) according to the embodiment satisfies Formula 4-2, the optical system (1000) can improve chromatic aberration characteristics.

[0128] [Formula 5] 0.5 <L8S2_max_sag to Sensor<1.5

[0129] In Formula 5, L8S2_max_sag to Sensor means the distance from the maximum sag value of the sixteenth surface (S16) on the sensor side of the eighth lens (108) to the image sensor (300) in the direction of the optical axis. For example, L8S2_max_sag toSensor means the distance from the critical point (P2) of the sensor side surface of the eighth lens (108) to the image sensor (300) in the direction of the optical axis. When the optical system (1000) according to an embodiment satisfies Formula 5, the optical system (1000) can ensure that the optical filter (500) can be disposed in the space between the lens portion (100) and the image sensor (300), thereby having improved assemblability. In addition, when the optical system (1000) satisfies Formula 5, the optical system (1000) can ensure a distance for module manufacturing. Preferably, the value of Formula 5 can satisfy: 0.5 <L8S2_max_sag to Sensor<1。

[0130] In the lens data of the present embodiment, for the convenience of designing the optical system (1000), the position of the filter (500) is set, and in detail, the distance between the last lens and the filter (500) and the distance between the image sensor (300) and the filter (500) are set, and the filter (500) can be freely set within a range where the last lens and the image sensor (300) do not contact each other. Therefore, the value of L8S2_max_Sag to Sensor in the lens data can be less than the BFL (Back focal length) of the optical system (1000), and the position of the filter (500) can be moved within a 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 (P2) of 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.

[0131] [Formula 6]1 <BFL / L8S2_max_sag to Sensor<2

[0132] In Formula 6, BFL (Back focal length) means the distance (unit: mm) from the center of the sixteenth surface (S16) on the sensor side of the eighth lens (108) closest to the image sensor (300) on the optical axis (OA) to the image surface of the image sensor (300). When the optical system (1000) according to the embodiment satisfies 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 maximum sag value can be the position of the critical point. Formula 6 can satisfy: 1.5≤BFL / L8S2_max_sag to Sensor<2.

[0133] [Equation 7] 5<|L8S2_max slope|<65

[0134] In Formula 7, L8S2_max slope means the maximum value of the tangential angle measured on the sensor-side sixteenth surface (S16) of the eighth lens (108) (unit: degree). In detail, in the sixteenth surface (S16), L8S2_maxslope means the angle value of the point having the maximum tangential angle relative to a virtual line extending in a direction perpendicular to the optical axis (OA) (unit: degree). When the optical system (1000) according to the embodiment satisfies Formula 7, the optical system (1000) can control the occurrence of lens glare. Preferably, Formula 7 can satisfy 20≤|L8S2_max slope|≤50.

[0135] [Equation 8] 1 < Inf82 < 1.5

[0136] In Equation 8, Inf82 may refer to the distance from the optical axis (OA) to the critical point (or inflection point) of the sixteenth surface (S16) on the sensor side of the eighth lens (108). Inf82 may be within 1.3 mm ± 0.2 mm from the optical axis (OA). When the optical system (1000) according to the embodiment satisfies Equation 8, the influence on the thinness ratio of the optical system (1000) can be suppressed.

[0137] [Equation 9] 1 < CG7 / G7_min < 15

[0138] Equation 9 refers to the minimum distance (unit: mm) between the seventh lens (107) and the eighth lens (108) and the distance (CG7) based on the optical axis (OA) between the seventh lens (107) and the eighth lens (108). When the optical system (1000) according to the embodiment satisfies Equation 9, the optical system (1000) can improve the distortion aberration characteristics and can have good optical performance in the peripheral part of the FOV. Equation 9 may satisfy: 5 < CG7 / G7_min < 12 or 8 < CG7 / G7_min ≤ 10.

[0139] [Equation 10] 0 < CG7 / EG7 < 2

[0140] In Equation 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 region between the seventh lens (107) and the eighth lens (108) are satisfied, good optical performance can be achieved in the central part and the peripheral part of the FOV. In addition, the optical system (1000) can reduce distortion and thus has improved optical performance. Preferably, Equation 10 may satisfy: 0.5 < CG7 / EG7 < 1.2.

[0141] [Equation 11] 0.01 < CG1 / CG6 < 1

[0142] In Equation 11, when the optical axis distance (CG1) between the first lens (101) and the second lens (102) and the optical axis distance (CG6) between the sixth lens and the seventh lens (106, 107) are satisfied, the optical system (1000) can improve the aberration characteristics and control the size of the optical system (1000), such as reducing the TTL (total track length). Preferably, Equation 11 may satisfy: 0.01 < CG1 / CG6 < 0.5.

[0143] [Equation 11-1] 3 < CA_L8S2 / CG7 < 20

[0144] In Equation 11-1, CA_L8S2 is the effective diameter of the largest lens surface and is the effective diameter of the sixteenth surface (S16) on the sensor side of the eighth lens (108). When the optical system (1000) according to the embodiment satisfies Equation 11-1, the optical system (1000) can improve aberration characteristics and control the reduction of TTL (total track length). Preferably, Equation 11-1 can be satisfied as: 10 < CA_L8S2 / CG7 < 15.

[0145] [Equation 11-2] 3 < CA_L7S2 / CG7 < 15

[0146] Equation 11-2 can set the effective diameter (CA_L7S2) of the fourteenth surface (S14) on the sensor side of the seventh lens (107) and the optical axis distance between the seventh lens and the eighth lens (107, 108). When the optical system (1000) according to the embodiment satisfies Equation 11-2, the optical system (1000) can improve aberration characteristics and control the reduction of TTL (total track length). Preferably, Equation 11-2 can be satisfied as: 5 < CA_L7S2 / CG7 < 13.

[0147] [Equation 12] 0 < CT1 / CT7 < 2

[0148] In Equation 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) can have improved aberration characteristics. Additionally, the optical system (1000) has good optical performance at the set FOV and can control TTL (total track length). Preferably, Equation 12 can be satisfied as: 0.5 < CT1 / CT7 < 1.

[0149] [Equation 13] 0 < CT6 / CT7 < 3

[0150] In Equation 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 reduce the manufacturing precision of the seventh lens (107) and the eighth lens (108), and can improve the optical performance of the central part and the peripheral part of the FOV. Preferably, Equation 13 can be satisfied as: 0 < CT6 / CT7 < 1. The central thicknesses of the fifth lens, the sixth lens, and the seventh lens can satisfy: (CT5 + CT6) < CT7. Additionally, the central thicknesses of the first lens, the sixth lens, the seventh lens, and the eighth lens can satisfy: CT6 < CT8 < CT1 < CT7.

[0151] [Equation 14] <L7R2 / L8R1<2

[0152] In Formula 14, L7R2 means the radius of curvature of the fourteenth surface (S14) of the seventh lens (107) on the optical axis (unit: mm), and L8R1 means 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 Formula 14, the aberration characteristics of the optical system (1000) can be improved. Preferably, Formula 14 can satisfy: <L7R2 / L8R1<1。

[0153] [Formula 15] 0<(CG6-EG6) / (CG6)<2

[0154] When Formula 15 satisfies the center distance (CG6) and edge distance (CG7) between the sixth lens and the seventh lens (106, 107), the optical system (1000) can reduce distortion and have improved optical performance. When the optical system (1000) according to the embodiment satisfies Formula 15, the optical performance of the central part and the peripheral part of the FOV can be improved. Formula 15 can preferably satisfy: 0<(CG6-EG6) / (CG6)<1. Here, comparing the center distances (CG) between the fourth lens, the fifth lens, the sixth lens, the seventh lens and the eighth lens, it can satisfy: CG4 <CG6<CG5<CG7。

[0155] [Formula 16]1 <CA_L1S1 / CA_L3S1<2

[0156] In Formula 16, CA_L1S1 means an effective diameter (clear aperture (Clear aperture): CA) of the first surface (S1) of the first lens (101), and CA_L3S1 means an effective diameter of the fifth surface (S5) of the third lens (103). When the optical system (1000) according to an embodiment satisfies Formula 16, the optical system (1000) can control light incident to the first lens group (LG1) and have improved aberration control characteristics. Formula 16 may preferably satisfy: 1 <CA_L1S1 / CA_L3S1<1.5。

[0157] [Formula 17]1 <CA_L7S2 / CA_L4S2<5

[0158] In Formula 17, CA_L4S2 means the effective diameter of the eighth surface (S8) of the fourth lens (104), and CA_L7S2 means the effective diameter of the fourteenth surface (S14) of the seventh lens (107). When the optical system (1000) according to the embodiment satisfies Formula 17, the optical system (1000) can control the light incident to the second lens group (LG2) and improve the aberration characteristics. Preferably, Formula 17 can satisfy: 1 <CA_L7S2 / CA_L4S2<3。

[0159] [Equation 18] 0.5 <CA_L3S2 / CA_L4S1<1.5

[0160] In Formula 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 optical system (1000) can improve chromatic aberration and control vignetting to improve optical performance. Preferably, Formula 18 can satisfy: 0.7 <CA_L3S2 / CA_L4S1<1。

[0161] [Equation 19] 0.1 <CA_L5S2 / CA_L7S2<1

[0162] In Formula 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 system (1000) can improve chromatic aberration. Preferably, Formula 19 can satisfy: 0.4≤CA_L5S2 / CA_L7S2≤0.7.

[0163] [Formula 20]1 <CA_L8S2 / CA_L1S1<5

[0164] In Formula 20, when the effective diameter (CA_L8S1) of the sixteenth surface (S16) of the eighth lens (108) and the effective diameter (CA_L1S1) of the first surface (S1) of the first lens (101) are satisfied, the optical system (1000) can set the FOV and size of the optical system. Preferably, Formula 20 can satisfy: <CA_L8S2 / CA_L1S1<3.5。

[0165] [Equation 21] 0.8 <CG3 / EG3<5

[0166] In Formula 21, when the distance (CG3) between the third lens and the fourth lens (103, 104) on the optical axis (OA) and the edge distance (EG3) between the third lens and the fourth lens (103, 104) are satisfied, the optical system (1000) can reduce chromatic aberration, improve aberration properties, and control vignetting to improve optical performance. Preferably, Formula 21 can satisfy: 1 <CG3 / EG3<2。

[0167] [Formula 22]1 <CG6 / EG6<5

[0168] In Formula 22, when the center distance (CG7) and the edge distance (EG7) between the seventh lens (107) and the eighth lens (108) are satisfied, the optical system has good optical performance even in the central and peripheral parts of the FOV, and the occurrence of distortion can be suppressed.

[0169] At least one of Equation 21 and Equation 22 may further include at least one of Equations 22-1 to 22-5.

[0170] [Formula 22-1]0 <CG1 / EG1<1

[0171] [Formula 22-2]1 <CG2 / EG2<3

[0172] [Formula 22-3]0 <CG4 / EG4<1.2

[0173] [Formula 22-4]1 <CG5 / EG5<10

[0174] [Formula 22-5]0 <CG8 / EG8<2

[0175] [Equation 23] <G7_max / CG7<2

[0176] In Formula 23, G7_Max means the maximum distance among the distances (unit: mm) between the seventh lens and the eighth lens (107, 108). When the optical system (1000) according to the embodiment satisfies Formula 23, the optical performance of the peripheral part of the FOV can be improved, and the distortion of the aberration characteristics can be suppressed. Preferably, Formula 23 can satisfy: 0.5 <G7_max / CG7<1.5。

[0177] [Equation 24] <CT6 / CG6<2

[0178] In Formula 24, the thickness (CT6) of the sixth lens (106) on the optical axis (OA) and the distance (CG6) between the sixth lens (106) and the seventh lens (107) on the optical axis (OA) are satisfied. In this case, the optical system (1000) can reduce the effective diameters of the sixth lens and the seventh lens and the center distance between adjacent lenses, and improve the optical performance of the peripheral portion of the FOV. Preferably, Formula 24 can satisfy: <CT6 / CG6<1。

[0179] [Formula 25]1 <CT6 / CG5<3

[0180] In Formula 25, when the thickness (CT6) of the sixth lens (106) on the optical axis (OA) and the distance (CG5) between the fifth lens and the sixth lens (105, 106) are satisfied, the optical system (1000) can reduce the effective diameters of the fifth lens and the sixth lens and the distance between the fifth lens and the sixth lens, and improve the optical performance of the peripheral portion of the FOV. Preferably, Formula 25 can satisfy: 1 <CT6 / CG5<2。

[0181] [Equation 26] 0.1 <CT7 / CG5<1

[0182] When Formula 26 satisfies the thickness (CT7) of the seventh lens (107) on the optical axis (OA) and the distance (CG5) between the fifth lens and the sixth lens (105, 106), the optical system (1000) can reduce the effective diameter of the seventh lens and the center distance between the fifth lens and the sixth lens, and improve the optical performance of the peripheral part of the FOV. Preferably, Formula 26 can satisfy: 0.1 <CT7 / CG5<0.8。

[0183] [Equation 27] 50<|L5R2 / CT5|<400

[0184] When Formula 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, Formula 27 can satisfy: 100<|L5R2 / CT5|<200.

[0185] [Equation 28] <L5R1 / L7R1<10

[0186] When 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, Formula 28 can satisfy: 1 <L5R1 / L7R1<5。

[0187] [Equation 29] <L1R1 / L1R2<1

[0188] Formula 29 can set the curvature radii of the object-side first surface (S1) and the object-side second surface (S2) of the first lens (101), and when these curvature radii are satisfied, the lens size and resolution can be determined. Preferably, Formula 29 can satisfy: <L1R1 / L1R2≤0.5。

[0189] [Equation 30] <L2R2 / L2R1<1

[0190] Formula 30 can set the curvature radii of the third surface (S3) and the fourth surface (S4) on the object side of the second lens (102), and when these curvature radii are satisfied, the resolution of the lens can be determined. Preferably, Formula 30 can satisfy: <L2R2 / L2R1≤0.8。

[0191] At least one of Equation 28, Equation 29, and Equation 30 may include at least one of the following Equations 30-1 to 30-6, and the resolving power of each lens may be determined.

[0192] [Formula 30-1]0 <L3R1 / L3R2<1

[0193] [Formula 30-2] 1<|L4R1 / L4R2|<5

[0194] [Formula 30-3]0 <L5R1 / L5R2<1

[0195] [Formula 30-4]1≤L6R1 / L6R2<3

[0196] [Formula 30-5]0 <L7R1 / L7R2<1.5

[0197] [Formula 30-6] 0<|L8R2 / L8R1|<1

[0198] [Equation 31] <CT_Max / CG_Max<2

[0199] In Formula 31, the maximum value (CT_max) of the maximum thickness 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 (total track length) can be reduced. Preferably, Formula 31 can satisfy: 1 <CT_Max / CG_Max<1.5。

[0200] [Equation 32] 0.5 < ΣCT / ΣCG < 2

[0201] In Formula 32, ΣCT means the sum of the thickness (unit: mm) of each lens in the plurality of lenses on the optical axis (OA), and ΣCG means 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 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, TTL (total track length) can be reduced. Preferably, Formula 32 can satisfy: 1<ΣCT / ΣCG<1.8.

[0202] [Equation 33] 10<∑Index<30

[0203] In Formula 33, ∑Index means the sum of the refractive index of each lens in the plurality of lenses at the d-line. When the optical system (1000) according to the embodiment satisfies Formula 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 lens to the eighth lens (101 to 108) can be 1.55 or greater. Preferably, Formula 33 can satisfy: 10<∑Index<20.

[0204] [Equation 34] 10<∑Abb / ∑Index<50

[0205] In Formula 34, ∑Abbe means the sum of the Abbe's number of each lens in the plurality of lenses. When the optical system (1000) according to the embodiment satisfies Formula 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 50 or less. Preferably, Formula 34 may satisfy: 10<∑Abb / ∑Index<30.

[0206] [Formula 35]0<|Max_distortion|<5

[0207] In Formula 35, Max_distortion means the maximum value of the distortion in the area 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 Formula 35, the optical system (1000) can improve the distortion characteristics. Preferably, Formula 35 can satisfy: 1<|Max_distortion|<3.

[0208] [Equation 36] <EG_Max / CT_Max<2

[0209] In Formula 36, ​​CT_max means the thickest thickness (unit: mm) among the thicknesses of each lens in the plurality of lenses on the optical axis (OA), and EG_Max means the maximum edge side distance between two adjacent lenses. When the optical system (1000) according to the embodiment satisfies Formula 36, ​​the optical system (1000) has a set FOV and focal length, and can have good optical performance in the peripheral portion of the FOV. Preferably, Formula 36 can satisfy: <EG_Max / CT_Max<1。

[0210] [Equation 37] 0.5 <CA_L1S1 / CA_min<2

[0211] In Formula 37, when the effective diameter (CA_L1S1) of the first surface (S1) of the first lens (101) and the minimum effective diameter (CA_Min) among the effective diameters of the first to sixteenth surfaces (S1 to S16) 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, Formula 37 can satisfy: 1 <CA_L1S1 / CA_min<2。

[0212] [Formula 38]1 <CA_max / CA_min<5

[0213] In Formula 38, CA_max means the maximum effective diameter among the object side surfaces and the sensor side surfaces of the plurality of lenses, and means the maximum effective diameter among the effective diameters (unit: mm) of the first to sixteenth surfaces (S1 to S16). When the optical system (1000) according to the embodiment satisfies Formula 38, the optical system (1000) can provide a slim and compact optical system while maintaining optical performance. Preferably, Formula 38 can satisfy: 2 <CA_max / CA_min<4。

[0214] [Formula 39]1 <CA_max / CA_Aver<3

[0215] In Formula 39, the maximum effective diameter (CA_max) and the average effective diameter (CA_Aver) 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, Formula 39 can satisfy: 1.5 <CA_max / CA_AVR<2.5。

[0216] [Equation 40] 0.1 <CA_min / CA_Aver<1

[0217] In Formula 40, the minimum effective diameter (CA_min) and the average effective diameter (CA_Aver) of the object side surface and the sensor side surface of the plurality of lenses can be set, and when these are satisfied, a thin and compact optical system can be provided. Preferably, Formula 40 can satisfy: 0.1 <CA_min / CA_AVR≤0.8。

[0218] [Equation 41] 0.1 <CA_max / (2×ImgH)<1

[0219] In Formula 41, the maximum effective diameter (CA_max) among 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, and when satisfied, the optical system (1000) has good optical performance in the central part and the peripheral part of the FOV, and provides a thin and compact optical system. Here, ImgH may be in the range of 4 mm to 10 mm. Preferably, Formula 41 may satisfy: 0.5≤CA_max / (2*ImgH)<1.

[0220] [Equation 42] 0.1 <TD / CA_max<1.5

[0221] In Formula 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, it 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 Formula 42, a slim and compact optical system can be provided. Preferably, Formula 42 can satisfy: 0.5 <TD / CA_max<1。

[0222] [Formula 43] <F / L7R2<5

[0223] In Formula 43, the total effective focal length (F) of the optical system (1000) and the radius of curvature (L7R2) of the fourteenth surface (S14) of the seventh lens (107) can be set. When these are satisfied, the optical system (1000) can reduce the size of the optical system (1000), such as TTL. Preferably, Formula 43 can satisfy: 1 <F / L7R2<3。

[0224] Formula 43 may also include the following Formula 43-1.

[0225] [Formula 43-1]1 <F / F#<6

[0226] F# may refer to the F number. Preferably, formula 43-1 may satisfy: 2 <F / F#<5。

[0227] [Formula 43-2]0 <F / L8R2<1

[0228] Formula 43-2 can set the total effective focal length (F) of the optical system (1000) and the radius of curvature (L8R2) of the sixteenth surface (S16) of the eighth lens (108). Preferably, Formula 43-2 can satisfy: <F / L8R2<0.5。

[0229] [Formula 44]

[0230] 1 <F / L1R1<10

[0231] In Formula 44, the radius of curvature (L1R1) of the first surface (S1) of the first lens (101) and the total effective focal length (F) can be set, and when they are satisfied, the optical system (1000) can be reduced in size, for example, the TTL (total track length) can be reduced. Preferably, Formula 44 can satisfy: <F / L1R1<5。

[0232] [Formula 45]0 <EPD / L8R2<5

[0233] In Formula 45, EPD means the entrance pupil diameter (unit: mm) of the optical system (1000), and L8R2 means the 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 Formula 45, the optical system (1000) can control the overall brightness and can have good optical performance in the central part and the peripheral part of the FOV. Preferably, Formula 45 can satisfy: <EPD / L8R2<1。

[0234] Formula 45 may also include the following Formula 45-1.

[0235] [Formula 45-1]1 <EPD / F#<3

[0236] [Equation 46] 0.5 <EPD / L1R1<8

[0237] Formula 46 means the relationship between the EPD 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, Formula 46 can satisfy: 0.5 <EPD / L1R1<2。

[0238] [Formula 47]-5 <F1 / F2<0

[0239] In equation 47, the focal lengths (F1, F2) of the first lens and the second lens (101, 102) can be set. Therefore, the resolution can be improved by adjusting the refractive power of the incident light of the first lens and the second lens (101, 102), and the TTL can be controlled. Preferably, equation 47 can satisfy: <F1 / F2<0。

[0240] [Formula 48]1 <F12 / F<5

[0241] By setting the composite focal length (F12) and the total focal length (F) of the first lens and the second lens in equation 48, the optical system (1000) can improve the resolution by adjusting the refractive power of the incident light, and the optical system (1000) can control the TTL (total track length). Preferably, equation 48 can satisfy: <F12 / F<3。

[0242] [Formula 49] 1<|F48 / F13|<4

[0243] In Formula 49, the composite 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 composite 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 condition is satisfied, the resolution can be improved by controlling the refractive power of the first lens group and the refractive power of the second lens group, and the optical system can be provided in a slim and compact size. In addition, when Formula 49 is satisfied, the optical system (1000) can improve aberration characteristics such as chromatic aberration and distortion aberration. The above Formula 49 can preferably satisfy: 1<|F48 / F13|<2. Here, F13>0 and F48<0 can be satisfied. In addition, the following formula can satisfy: F12>F13.

[0244] [Formula 50]0 <F1 / F<3

[0245] In equation 50, the total focal length (F) and refractive power of the first lens (101) can be set, and the resolution can be improved. Equation 50 can satisfy: <F1 / F<2。

[0246] [Equation 50-1] 0 < |F2 / F| < 5 (where F > 0, F2 < 0)

[0247] [Equation 50-2] 0 < F3 / F2 < 5 (where F3 > 0)

[0248] [Equation 50-3] 5 < |F4 / F| < 25 (where F4 < 0)

[0249] [Equation 50-4] 0 < F5 / F < 10 (where F5 > 0)

[0250] [Equation 50-5] 1 < |F6 / F| < 15 (where F6 < 0)

[0251] [Equation 50-6] 5 < F7 / F < 25 (where F7 > 0)

[0252] [Equation 50-7] 0 < |F8 / F| < 5 (where F8 < 0)

[0253] In Equations 50-1 to 50-7, F3, F4, F5, F6, F7, and F8 refer to the focal lengths (unit: mm) of the third lens, fourth lens, fifth lens, sixth lens, seventh lens, and eighth lens (103, 104, 105, 106, 107, 108), and when this condition is satisfied, 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.

[0254] [Equation 51] 0 < F1 / F13 < 2

[0255] 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) from the first lens to the third lens in Equation 51. Preferably, Equation 51 can satisfy: 0 < F1 / F13 < 1.5.

[0256] [Equation 52] 0 < F1 / |F48| < 2

[0257] In Equation 52, by setting the focal length (F1) of the first lens and the combined focal length (F48) from the fourth lens to the eighth lens, the size and resolution of the optical system can be adjusted. Preferably, Equation 52 can satisfy: 0 < F1 / |F48| < 1.

[0258] Here, when the aperture stop is provided on the circumferential surface on the sensor side of the second lens, based on the position of the aperture stop, the combined focal length of the first lens and the second lens is F12, and the combined focal length from the third lens to the eighth lens is F38, and the following equation can be satisfied: F12 > F13, and |F38| > |F48|.

[0259] [Equation 53] 0 < |F1 / F4| < 1

[0260] By setting the focal length (F1) of the first lens and the focal length (F4) of the fourth lens in Equation 53, 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, Equation 53 can satisfy: 0 < F1 / |F4| < 0.5.

[0261] [Equation 54] 2mm < TTL < 20mm

[0262] In Equation 54, TTL (Total tracklength) means the distance (unit: mm) from the vertex of the first surface (S1) of the first lens (101) to the image surface of the image sensor (300) on the optical axis (OA). Preferably, Equation 54 can satisfy: 5mm < TTL < 15mm, and thus a thin and compact optical system can be provided.

[0263] [Equation 55] 2mm < ImgH

[0264] Equation 55 sets the diagonal length (2*ImgH) of the image sensor (300) to be more than 4mm, thereby providing an optical system with high resolution. Equation 55 can preferably satisfy: 4mm ≤ ImgH < 12mm.

[0265] [Equation 56] BFL < 2.5

[0266] In Equation 56, BFL (Back focal length) is less than 2.5mm, so that the installation space of the filter (500) can be ensured, and the assembly of components is improved through the gap between the image sensor (300) and the last lens, and the coupling reliability is increased. Equation 56 can preferably satisfy: 0 < BFL < 1.2mm.

[0267] [Equation 57] 2mm < F < 20mm

[0268] In Equation 57, the total focal length (F) can be set according to the optical system, and preferably, it can satisfy: 5 < F < 15.

[0269] [Equation 58] FOV < 120 degrees

[0270] In Equation 58, FOV (Field of view) means the FOV of the optical system (1000), and an optical system with less than 120 degrees can be provided. The FOV can be greater than 70 degrees, for example, in the range of 70 degrees to 100 degrees.

[0271] [Equation 59] 0.5 < TTL / CA_max < 2

[0272] In Formula 59, by setting the maximum effective diameter (CA_max) and TTL (Total track length) among the object side surface and the sensor side surface of the plurality of lenses, a thin and compact optical system can be provided. Preferably, Formula 59 can satisfy: 0.5 <TTL / CA_max<1。

[0273] [Equation 60] 0.5 <TTL / ImgH<3

[0274] Formula 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 Formula 60, the optical system (1000) ensures a BFL (Back focal length) for applying 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 slim structure. Preferably, Formula 60 can satisfy: 0.8 <TTL / ImgH<2。

[0275] [Equation 61] 0.01 <BFL / ImgH<0.5

[0276] Formula 61 can set the distance between the image sensor (300) and the last lens between the optical axis and the length of the image sensor (300) in the diagonal direction from the optical axis. When the optical system (1000) according to the embodiment satisfies Formula 61, the optical system (1000) applies a relatively large image sensor (300), such as a large image sensor (300) of about 1 inch. The back focal length (BFL) of the image sensor (300) can be ensured, and the distance between the last lens and the image sensor (300) can be minimized, so that good optical characteristics can be obtained at the central part and the peripheral part of the FOV. Preferably, Formula 61 can satisfy: 0.1≤BFL / ImgH≤0.3.

[0277] [Formula 62]4 <TTL / BFL<10

[0278] Formula 62 may 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 Formula 62, the optical system (1000) ensures the BFL and can be provided as slim and compact. Formula 62 may satisfy: <TTL / BFL<10。

[0279] [Equation 63] 0.5 <F / TTL<1.5

[0280] Formula 63 can set the total focal length (F) and total optical axis length (TTL) of the optical system (1000). Therefore, a thin and compact optical system can be provided. Formula 63 can preferably satisfy: 0.5 <F / TTL<1.2。

[0281] [Formula 63-1]0 <F# / TTL<0.5

[0282] Formula 63-1 can set the F number (F#) and the total optical axis length (TTL) of the optical system (1000). Therefore, a thin and compact optical system can be provided.

[0283] [Formula 64]3 <F / BFL<10

[0284] 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 (unit, mm). When the optical system (1000) according to the embodiment satisfies 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 it can have good optical characteristics in the peripheral part of the FOV. Preferably, Formula 64 can satisfy: 5 <F / BFL<10。

[0285] [Equation 65] 0.1 <F / ImgH<3

[0286] Formula 65 can set the total focal length (F) (unit: mm) of the optical system (1000) and the diagonal length (ImgH) of the image sensor (300) from the optical axis. The optical system (1000) can have improved aberration characteristics by applying a relatively large image sensor (300), such as a large image sensor (300) of about 1 inch. Preferably, Formula 65 can satisfy: 0.8≤F / ImgH<2.

[0287] [Formula 66]1 <F / EPD<5

[0288] 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, Formula 66 can satisfy: 1.5≤F / EPD<4.

[0289] [Formula 67]0 <BFL / TD<0.3

[0290] In Equation 67, the back focal length (BFL) between the image sensor (300) and the last lens and the total 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, Equation 67 can satisfy: 0 < BFL / TD ≤ 0.2. When BFL / TD exceeds 0.3, since BFL is designed to be larger 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, and as a result, there are problems such as a decrease in resolution, such as deterioration of aberration characteristics.

[0291] [Equation 68] 0 < EPD / ImgH / FOV < 0.2

[0292] In Equation 68, the relationship between the size of EPD, half of the length of the maximum diagonal of the image sensor (ImgH), and FOV can be set. Therefore, the overall size and brightness of the optical system can be controlled. Equation 68 can preferably satisfy: 0 < EPD / ImgH / FOV < 0.1.

[0293] [Equation 69] 5 < FOV / F# < 50

[0294] Equation 69 can establish the relationship between the FOV and the F-number of the optical system. Equation 69 can preferably satisfy: 30 < FOV / F# < 50.

[0295] [Equation 70] 0 < n1 / n2 < 1.5

[0296] When the refractive indices (n1, n2) of the first lens and the second lens (101, 102) at the d-line of Equation 70 satisfy the above range, the optical system can improve the resolution of the incident light. Preferably, Equation 70 can satisfy: 0 < n1 / n2 < 1.

[0297] [Equation 71] 0 < n3 / n4 < 1.5

[0298] When the refractive indices (n3, n4) of the third lens and the fourth lens (103, 104) at the d-line of Equation 71 satisfy the above range, the optical system can improve the resolution of the incident light of the second lens group (LG2). Preferably, Equation 71 can satisfy: 0 < n3 / n4 < 1.

[0299] [Equation 72] 0 < Inf61 / Inf62 < 1

[0300] In Formula 72, the distance (Inf61) from the optical axis (OA) to the critical point of the object side surface (S11) of the sixth lens (106) and the distance (Inf62) from the optical axis (OA) to the critical point of the sensor side surface (S12) can be set, and when this condition is met, the aberration of the sixth lens can be controlled to be satisfactory. Formula 72 can satisfy: 0.5 <Inf61 / Inf62<1。

[0301] [Formula 73] <Inf61 / Inf72<1

[0302] In Formula 73, the distance (Inf61) from the optical axis (OA) to the critical point of the object side surface (S11) of the sixth lens (106) and the distance (Inf72) from the optical axis (OA) to the critical point of the sensor side surface (S14) of the seventh lens (107) can be set, and when the conditions are met, the aberrations of the sixth lens and the seventh lens can be controlled to be satisfactory. Formula 73 can satisfy: 0.3 <Inf61 / Inf72<0.8。

[0303] [Formula 74]0 <Inf62 / Inf72<1

[0304] In Formula 74, the distance (Inf62) from the optical axis (OA) to the critical point of the sensor side surface (S12) of the sixth lens (106) and the distance (Inf72) from the optical axis (OA) to the critical point of the sensor side surface (S14) of the seventh lens (107) can be set, and when this condition is met, the aberrations of the sixth lens and the seventh lens can be controlled to be satisfactory. Formula 74 can satisfy: 0.5 <Inf62 / Inf72<1。

[0305] [Formula 75]0 <Inf61 / semi-Aperture_L6S1<1

[0306] In Formula 75, the distance (Inf61) from the optical axis (OA) to the critical point of the object side surface S11 of the sixth lens (106) and the effective radius (semi-Aperture_L6S1) of the object side surface of the sixth lens (106) can be set, and when this condition is met, the aberration of the object side surface of the sixth lens can be controlled to be satisfactory. Formula 75 can satisfy: 0.2 <Inf61 / semi-Aperture_L6S1<0.8。

[0307] [Formula 76]0 <Inf62 / semi-Aperture_L6S2<1

[0308] In Formula 76, the distance (Inf62) from the optical axis (OA) to the critical point of the sensor side surface (S12) of the sixth lens (106) and the effective radius (semi-Aperture_L6S2) of the sensor side surface of the sixth lens (106) can be set, and when this condition is met, the aberration of the sensor side surface of the sixth lens can be controlled to be satisfactory. Formula 76 can satisfy: 0.1 <Inf62 / semi-Aperture_L6S2<0.7。

[0309] [Formula 77]0 <Inf71 / semi-Aperture_L7S1<0.9

[0310] In Formula 77, the distance (Inf71) from the optical axis (OA) to the critical point of the object side surface (S13) of the seventh lens (107) and the effective radius (semi-Aperture_L7S1) of the object side surface of the seventh lens (107) can be set, and when this condition is met, the aberration of the object side surface of the seventh lens can be controlled to be satisfactory. Formula 77 can satisfy: <Inf71 / semi-Aperture_L7S1<0.5。

[0311] [Formula 78]0 <Inf72 / semi-Aperture_L7S2<0.9

[0312] In Formula 78, the distance (Inf72) from the optical axis (OA) to the critical point of the sensor side surface (S14) of the seventh lens (107) and the effective radius (semi-Aperture_L7S2) of the sensor side surface of the seventh lens (106) can be set. When this condition is met, the aberration of the sensor side surface of the seventh lens can be controlled to be satisfactory. Formula 78 can satisfy: <Inf72 / semi-Aperture_L7S2<0.7。

[0313] [Formula 79]0<|Max_Sag71| / semi-Aperture_L7S1<0.8

[0314] In Formula 79, the maximum height (Max_Sag71) of the thirteenth surface (S13) from a straight line orthogonal to the center of the thirteenth surface (S13) on the object side of the seventh lens (107) and the effective radius of the thirteenth surface (S13) can be set. When this condition is met, the aberration of the thirteenth surface of the seventh lens can be controlled to be satisfactory. Preferably, Formula 79 can satisfy: 0<|Max_Sag71| / semi-Aperture_L7S1<0.5.

[0315] [Equation 80] 0<|Max_Sag72| / semi-Aperture_L7S2<0.8

[0316] In Formula 80, the maximum height (Max_Sag72) of the fourteenth surface (S14) from a straight line orthogonal to the center of the sensor-side fourteenth surface (S14) of the seventh lens (107) and the effective radius of the fourteenth surface (S14) are set. When this condition is satisfied, the aberration of the fourteenth surface of the seventh lens can be controlled to be satisfactory. Preferably, Formula 80 can satisfy: 0<|Max_Sag72| / semi-Aperture_L7S2<0.6.

[0317] [Formula 81]

[0318]

[0319] In Formula 81, Z is the sag and may mean the distance from any position on the aspheric surface to the vertex of the aspheric surface in the direction of the optical axis. Y may mean the distance from any position on the aspheric surface to the optical axis in a direction perpendicular to the optical axis. C may mean the curvature of the lens, and K may mean the conic constant. In addition, A, B, C, D, E, and F may mean aspheric constants.

[0320] The optical system (1000) according to the embodiment may satisfy at least one or two or more of equations 1 to 80. 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 equations 1 to 80, the optical system (1000) has improved resolution and can improve aberration and distortion characteristics. In addition, the optical system (1000) can ensure the BFL (Back focal length) for applying a large-size image sensor (300), and can minimize the distance between the last lens and the image sensor (300), and thus has good optical performance in the central part and the peripheral part of the FOV. In addition, when the optical system (1000) satisfies at least one of equations 1 to 70, it can include a relatively large image sensor (300), have a relatively small TTL value, and can provide a thinner and more compact optical system and a camera module having the optical system.

[0321] 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.

[0322] Figure 3 Is based on having Figure 1An example of lens data of a first embodiment of the optical system, and Fig. 9 Is based on having Figure 1 An example of lens data of the second embodiment of the optical system.

[0323] like Figure 3 and Fig. 9 1 , the optical system according to the embodiment represents the radius of curvature (Radius of Curvature) of the first lens to the eighth lens (101 to 108) on the optical axis (OA), the center thickness (CT) of the lens and the center distance (CG) between the lenses, the refractive index (Refractive index) at the d line (588nm), the Abbe's number (Abbe's number) and the effective radius (Semi-aperture), and the focal length.

[0324] The sum of the refractive indexes of the plurality of lenses (100) is greater than 10, the sum of the Abbe numbers is greater than 200, the sum of the center thicknesses of all the lenses is 5 mm or less, for example, in the range of 3.5 mm to 5 mm, and the sum of the center distances of the first lens to the eighth lens on the optical axis is 4 mm or less, for example, in the range of 2 mm to 4 mm, and may 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 plurality of lenses (100) may be 4 mm or greater, for example, in the range of 4 mm to 6.5 mm, and the average value of the center thickness of each lens may be 0.8 mm or less, for example, in the range of 0.35 mm to 0.8 mm. The sum of the effective diameters of the plurality of lenses (100) is the sum of the effective diameters from the first surface (S1) to the sixteenth surface (S16), and may be 70 mm or more, for example, 70 mm to 110 mm.

[0325] In absolute values ​​of focal lengths, the focal length of the fourth lens (104) is the largest, and the focal length of any one of the first lens and the eighth lens (101, 108) is the smallest and can be set to be smaller than the focal lengths of the second lens and the third lens.

[0326] like Figure 4 and Fig.10As shown, the lens surface of at least one lens or all lenses in the plurality of lenses in the first embodiment and the second embodiment may include an aspheric surface having a 30th order aspheric coefficient. For example, the first lens to the eighth lens (101, 102, 103, 104, 105, 106, 107, 108) may include lens surfaces having a 30th order aspheric coefficient from the first surface (S1) to the sixteenth surface (S16). As described above, the aspheric surface having a 30th order aspheric surface coefficient (a value other than "0") can make the aspheric shape of the periphery change particularly large, so that the optical performance of the peripheral portion of the FOV can be well corrected.

[0327] like Figure 5 and Fig.11 As shown, the first thickness to the eighth thickness (T1 to T8) of the first lens to the eighth lens (101 to 108) can be expressed as a distance of 0.1 mm or more in the direction (Y) from the center to the edge of each lens, and for 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 expressed as a distance of 0.1 mm or more in the direction from the center to the edge.

[0328] The maximum thickness of the first thickness (T1) may be 1.6 times or more of the minimum thickness, for example, 1.6 times to 2.6 times. The maximum distance of the first distance (G1) may be 1.3 times or more of the minimum distance, for example, 1.3 times to 2.3 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 2.1 times. The maximum distance of the second distance (G2) may be 1.1 times or more of the minimum distance, for example, 1.1 times to 2.1 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 2.1 times. The maximum distance of the third distance (G3) may be 1.1 times or more of the minimum distance, for example, 1.1 times to 2.1 times. The difference between the maximum thickness and the minimum thickness of the fourth thickness (T4) may be 10% or less. The maximum distance of the fourth distance (G4) may be 1.2 times or more of the minimum distance, for example, 1.2 times to 2.2 times. The maximum thickness of the fifth thickness (T5) may be one or more times, for example, one to two times, the minimum thickness. The maximum distance of the fifth distance (G5) may be 1.1 times or more of the minimum distance, for example, 1.1 to 2.1 times. The maximum thickness of the sixth thickness (T6) may be 2.1 times or more of the minimum thickness, for example, 2.1 to 3.1 times. The maximum distance of the sixth distance (G6) may be 1.5 times or more of the minimum distance, for example, 1.5 to 2.5 times. The maximum thickness of the seventh thickness (T7) may be 1.1 times or more of the minimum thickness, for example, 1.1 to 2.1 times. The maximum distance of the seventh distance (G7) may be 5 times or more of the minimum distance, for example, 5 to 15 times. The maximum thickness of the eighth thickness (T8) may be 1.6 times or more of the minimum thickness, for example, 1.6 to 2.6 times. By using the first to eighth thicknesses (T1 to T8) and the first to seventh distances (G1 to G7), the optical system may be provided in a slim and compact size.

[0329] Figure 6 and Fig.12 It can be represented by the height (sag value) of the lens surface at a distance of 0.1 mm or more from a 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 an embodiment of the present invention, and Fig.15 It is shown Figure 6 and Fig.12 The curve diagram of Figure 6 , Fig.12 and Fig.15 As shown, the object side surface (L7S1) and the sensor side surface (L7S2) of the seventh lens (107) have a critical point at a distance of 3 mm or less from the optical axis, and the critical point of the object side surface (see Figure 2 P1) is closer to the optical axis than the critical point on the sensor side surface, and it can be seen that the sag value of L7S2 is greater than the sag value of L7S1 toward the sensor side. In addition, the object side surface of the eighth lens may be set to have no critical point, and the sensor side surface of the eighth lens may have a critical point with a smaller sensor side sag value than L7S1 and L7S2, and may have a critical point closer to the optical axis (see Figure 2 in P2).

[0330] Figure 7 is a graph showing light aberration characteristics of the optical system according to the first embodiment of the present invention, Figure 8 is a graph showing aberration characteristics of the optical system according to the first embodiment of the present invention, Fig.13 is a graph showing light aberration characteristics of an optical system according to a second embodiment of the present invention, and Fig.14 : is a graph showing aberration characteristics of the optical system according to the second embodiment of the present invention.

[0331] like Figure 7 , Figure 8 , Fig.13 and Fig.14 As shown, it is an analysis graph showing the lateral aberration in the region where the relative field height on the optical axis is 0.0 to 1.0 in the tangential field curvature and the sagittal field curvature of the optical system according to the first embodiment and the second embodiment, and it can be confirmed that for light in the wavelength band of about 470nm, about 510nm, about 555nm, about 610nm and about 650nm, an optical system with good lateral aberration correction can be obtained. 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 in the above examples, the lens system according to the first embodiment and the second embodiment of the present invention has an 8-piece lens configuration, is compact and lightweight, and at the same time, spherical aberration, astigmatism, distortion aberration, chromatic aberration and coma are all good. Since it can be calibrated and realized with high resolution, it can be used by being embedded in the optical device of the camera device.

[0332] Table 1 relates to the terms in the above-mentioned formulas in the optical system (1000) according to the first and second embodiments, and relates to TTL (Total track length), BFL (Back focal length), total effective focal length F value, ImgH, focal length of each lens from the first lens to the eighth lens (F1, F2, F3, F4, F5, F6, F7, F8), edge thickness, edge distance, composite focal length, etc. of the optical system (1000).

[0333]

Table 1

[0334]

[0335]

[0336] Table 2 is Figure 1 The result values ​​of the above-described equations 1 to 40 in the optical system (1000) are obtained. 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 equations 1 to 40. In detail, it can be seen that the optical system (1000) according to the embodiment satisfies all of equations 1 to 40. Therefore, the optical system (1000) can improve the optical performance and optical characteristics at the central part and the peripheral part of the FOV.

[0337]

Table 2

[0338]

[0339]

[0340]

[0341] Table 3 is Figure 1 The result values ​​of the above-described equations 41 to 80 in the optical system (1000) are obtained. Referring to Table 3, the optical system (1000) may satisfy at least one or two or more of equations 1 to 40 and at least one, two or more, or three or more of equations 41 to 80. In detail, it can be seen that the optical system (1000) according to the embodiment satisfies all of equations 1 to 80. Therefore, the optical system (1000) can improve the optical performance and optical characteristics at the central part and the peripheral part of the FOV.

[0342]

Table 3

[0343]

[0344]

[0345]

[0346] Fig.16 is a diagram showing that a camera module according to an embodiment is applied to a mobile terminal.

[0347] Reference Fig.16 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.

[0348] 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).

[0349] For example, the camera module (10) may include a first camera module (10A) and a second camera module (10B). In this case, at least one of the first camera module (10A) and the second camera module (10B) may include the above-mentioned optical system (1000). Therefore, the camera module (10) may have a slim structure and may have improved distortion characteristics and aberration characteristics. In addition, the camera module (10) may have good optical performance even in the central part and the peripheral part of the FOV.

[0350] In addition, the mobile terminal (1) may further include an automatic focusing device (31). The automatic focusing device (31) may include an automatic focusing function using a laser. The automatic focusing device (31) may be mainly used in a case where the automatic focusing function of the image using the camera module (10) is degraded (for example, at a distance of 10 m or less or in a dark environment). The automatic focusing device (31) may include a light emitting unit and a light receiving unit, the light emitting unit including a vertical cavity surface emitting laser (VCSEL) semiconductor device, and the light receiving unit converting light energy into electrical energy, such as a photodiode.

[0351] In addition, the mobile terminal (1) may further include a flash module (33). The flash module (33) may include a light emitting element that emits light therein. The flash module (33) may be operated by a camera operation of the mobile terminal or by a user's control.

[0352] The features, structures, effects, etc. described in the above-mentioned embodiments are included in at least one embodiment of the present invention, and are not necessarily limited to one embodiment. In addition, the features, structures, and effects shown in each embodiment can be combined or modified by a technician in the field to which each embodiment belongs relative to other embodiments. Therefore, the contents related to these combinations and variations should be interpreted as being included in the scope of the invention. Although described based on the embodiments, this is only an example, the present invention is not limited, and it will be obvious to those skilled in the art that various modifications and applications not shown above are feasible without departing from the basic features of the embodiments. For example, each component specifically shown in the present embodiment can be modified and implemented. And the differences related to these modifications and applications should be interpreted as being included in the scope of the present invention defined in the appended claims.

Claims

1. An optical system, comprising: first to eighth lenses arranged along the optical axis in a direction from the object side to the sensor side, wherein the first lens has positive (+) refractive power on the optical axis and has a convex object-side surface, Wherein, when the refractive index of the first lens (n1) and the refractive index of the second lens (n2) satisfy the following formula: <n1 / n2<1, wherein, among the first to eighth lenses, the number of lenses having a meniscus shape convex toward the object side on the optical axis (OA) is five or more, wherein each of the object-side surface and the sensor-side surface of the sixth lens has a critical point, wherein each of the object-side surface and the sensor-side surface of the seventh lens has a critical point, and The sensor-side surface of the seventh lens has a critical point disposed at an outer side based on the optical axis than the object-side surface and the sensor-side surface of the sixth lens.

2. The optical system according to claim 1, in, The object side surface of the eighth lens is set to have no critical point, Wherein, the sensor side surface of the eighth lens has a critical point, The critical point of the eighth lens is arranged to be closer to the optical axis than a critical point of an object-side surface and a sensor-side surface of the sixth lens.

3. The optical system according to claim 1, in, The refractive index of the first lens satisfies: 1.50 <n1<1.6, The refractive index of the second lens satisfies: 1.65 <n2。 4. The optical system according to claim 1, in, The first lens, the second lens, the third lens, the fifth lens, and the sixth lens have a meniscus shape that is convex toward the object side on the optical axis.

5. The optical system according to claim 4, in, The seventh lens has a meniscus shape that is convex toward the object side on the optical axis.

6. The optical system according to any one of claims 1 to 5, in, The maximum effective diameters (CA_max) of the object side surfaces and the sensor side surfaces of the first to eighth lenses satisfy the following equation: 0.1 <CA_max / (2*ImgH)<1, Wherein, the ImgH is 1 / 2 of the maximum diagonal length of the image sensor.

7. An optical system according to any one of claims 1 to 5, in, Among the object-side surfaces and sensor-side surfaces of the first to eighth lenses, the sensor-side surface of the eighth lens has the largest effective diameter (CA_max) and satisfies the following formula: 0.5 <TTL / CA_max<2 The TTL is an optical axis distance from the object side surface of the first lens to the image surface of the image sensor.

8. An optical system according to any one of claims 1 to 5, in, The focal length (F1) and the total focal length (F) of the first lens satisfy the following equation: <F1 / F<3。 9. The optical system according to claim 8, in, The focal length (F1) of the first lens and the focal length (F2) of the second lens satisfy the following formula: <F1 / F2<0。 10. The optical system according to any one of claims 1 to 5, in, The center thickness (CT6) of the sixth lens and the center thickness (CT7) of the seventh lens satisfy the following formula: <CT6 / CT7<1。 11. The optical system according to claim 4 or 5, The effective diameter of the object side surface of the first lens is CA_L1S1, in, The object side effective diameter of the third lens is CA_L3S1, The effective diameter of the eighth lens on the sensor side is CA_L8S2, and Among them, the following formula is satisfied: 1 <CA_L1S1 / CA_L3S1<2 1 <CA_L8S2 / CA_L1S1<5。 12. An optical system comprising: First to third lenses disposed on the object side; Fourth to eighth lenses disposed on the sensor side; as well as an aperture stop provided around the sensor-side surface of any one of the first to third lenses, wherein the sensor-side surface of the third lens faces the object-side surface of the fourth lens, wherein the sensor-side surface of the third lens has a concave shape on the optical axis, wherein the object side surface of the fourth lens has a convex shape on the optical axis, wherein the first to third lenses have a meniscus shape convex toward the object side on the optical axis, wherein effective diameters of the object-side surfaces and sensor-side surfaces of the first to third lenses gradually decrease from the object side toward the sensor side, The effective diameters of the object-side surfaces and the sensor-side surfaces of the fourth to eighth lenses gradually increase from the object side toward the sensor side.

13. The optical system according to claim 12, in, The composite focal length from the first lens to the third lens is F13, Wherein, the composite focal length from the fourth lens to the eighth lens is F48, and Among them, the following formula is satisfied: 1<|F48 / F13|<4.

14. The optical system according to claim 13, in, The aperture stop is disposed around the sensor-side surface of the second lens, Wherein, the composite focal length from the first lens to the second lens is F12, Wherein, the composite focal length from the third lens to the eighth lens is F38, and Among them, the following formula is satisfied: F12>F13 |F38|>|F48|.

15. An optical system according to any one of claims 12 to 14, in, The object side surface and the sensor side surface of the sixth lens have a critical point, Wherein, the sensor side surface of the seventh lens has a critical point, Wherein, the distance from the optical axis to the critical point of the object side surface of the sixth lens is Inf61, Wherein, the distance from the optical axis to the critical point of the sensor side surface of the sixth lens is Inf62, Wherein, the distance from the optical axis to the critical point of the sensor side surface of the seventh lens is Inf72, and Among them, the following formula is satisfied: 0 <Inf61 / Inf62<1 0 <Inf61 / Inf72<1 0 <Inf62 / Inf72<1。 16. An optical system according to any one of claims 12 to 14, in, The radius of curvature of the object side surface of the first lens is L1R1, The curvature radius of the sensor side surface of the first lens is L1R2, The radius of curvature of the object side surface of the second lens is L2R1, The radius of curvature of the sensor-side surface of the second lens is L2R2, and Among them, the following formula is satisfied: 0 <L1R1 / L1R2<1 0 <L2R2 / L2R1<1。 17. An optical system according to any one of claims 12 to 14, in, The object side surface and the sensor side surface of the first eighth lens have an aspherical shape on the optical axis, Wherein, the distance between the sensor side surface of the eighth lens and the image sensor satisfies the following formula: 1 <BFL / L8S2_max_sag to Sensor<2 Wherein, the BFL is the distance from the center of the sensor side surface of the eighth lens to the optical axis of the image sensor, and Wherein, L8S2_max_sag to Sensor is the distance from the maximum sag value of the sensor-side surface of the eighth lens to the image sensor.

18. An optical system according to any one of claims 12 to 14, in, The center thickness (CT1) of the first lens, the center thickness (CT2) of the second lens, and the center thickness (CT7) of the seventh lens satisfy the following formula: 2 <CT1 / CT2<4 0 <CT1 / CT7<2。 19. An optical system according to any one of claims 12 to 14, in, The sum of the center thicknesses of the first lens to the eighth lens (ΣCT) and the sum of the distances between two adjacent lenses (ΣCG) satisfy the following formula: 1<∑CT / ∑CG<1.

8.

20. A camera module, comprising: Image sensor; as well as an optical filter disposed between the image sensor and the last lens, wherein the optical system comprises the optical system according to claim 1 or 12, and Among them, the following formula is satisfied: 0.5 <F / TTL<1.5 0.5 <TTL / ImgH<3 (F is the average value of the total focal length in two directions orthogonal to the optical axis of the optical system, TTL (total track length) is the distance from the center of the object side surface of the first lens to the image surface of the image sensor on the optical axis, and ImgH is 1 / 2 of the maximum diagonal length of the image sensor.).

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