Optical system and camera module

Abstract

A camera module according to an embodiment of the present invention disclosed herein may comprise: a first lens group that is adjacent to an object and has negative (-) refractive power; a second lens group disposed on the sensor side of the first lens group; a third lens group disposed on the sensor side of the second lens group; and a fourth lens group that is disposed on the sensor side of the third lens group and has positive (+) refractive power. Lenses of the first to fourth lens groups are aligned along an optical axis, at least two of the first to fourth lens groups move along the optical axis according to an operating mode, the number of lenses in the first lens group is greater than the number of lenses in the second and third lens groups, and the optical axis distance between the fourth lens group and an image sensor is variable. The total number of lenses in the first to fourth lens groups is nL, the number of lens groups that move among the first to fourth lens groups is nMLG, and the equation 2 < nL / nMLG < 3 may be satisfied.

Description

Optical system and camera module

[0001] The present invention relates to an optical system for improved optical performance and a camera module including the same.

[0002] Camera modules perform the function of capturing objects and storing them as images or videos, and are installed in various applications. In particular, camera modules are manufactured in an ultra-small size and are applied to portable devices such as smartphones, tablet PCs, and laptops, as well as drones and vehicles, providing various functions. For example, the optical system of a camera module may include an imaging lens that forms an image and an image sensor that converts the formed image into an electrical signal. At this time, the camera module can perform an autofocus (AF) function that automatically adjusts the distance between the image sensor and the imaging lens to align the focal length of the lens, and can perform a zooming function that increases or decreases the magnification of a distant object through a zoom lens. In addition, the camera module adopts image stabilization (IS) technology to compensate for or prevent shaking of the image caused by camera movement due to an unstable fixed device or the user's movements.

[0003] The most important element for a camera module to obtain an image is the imaging lens that forms the image. Recently, interest in high resolution has been increasing, and research is being conducted on optical systems that include multiple lenses to achieve this. For example, research is being conducted using multiple imaging lenses with positive (+) or negative (-) refractive power to achieve high resolution. However, when multiple lenses are included, there is a problem in that it is difficult to derive excellent optical and aberration characteristics. 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, which increases the overall size of the module that includes the multiple lenses.

[0004] To achieve high-resolution and high-quality images, image sensors are increasing in size. However, as image sensors increase in size, the total track length (TTL) of optical systems containing multiple lenses also increases, leading to an increase in the thickness of cameras, mobile devices, and other devices containing the optical systems.

[0005] When the optical system includes a plurality of lenses, the position of at least one lens or a lens group including at least one lens can be controlled to perform functions such as zoom and autofocus (AF). However, when the lens or the lens group performs the function, the amount of movement of the lens or the lens group can increase exponentially. Accordingly, the optical system has a problem in that a lot of energy may be required to move the lens or the lens group, and a large volume is required considering the amount of movement. In addition, there is a problem in that aberration characteristics are deteriorated due to the movement of the lens or the lens group. Accordingly, there is a problem in that optical characteristics are deteriorated at a certain magnification when performing the zoom and autofocus (AF) functions. Therefore, a new optical system that can solve the above-described problems is required.

[0006] The present invention provides an optical system with improved optical characteristics. The present invention provides an optical system and camera module capable of photographing at various magnifications. The present invention provides an optical system and camera module with improved aberration characteristics at various magnifications. The present invention provides an optical system and camera module that can be implemented in a small and compact manner.

[0007] A camera module according to an embodiment of the invention includes a first lens group adjacent to an object and having negative (-) refractive power; a second lens group disposed on a sensor side of the first lens group; a third lens group disposed on a sensor side of the second lens group; and a fourth lens group disposed on a sensor side of the third lens group and having positive (+) refractive power, wherein lenses of the first to fourth lens groups are aligned along an optical axis, and at least two of the first to fourth lens groups move along the optical axis according to an operation mode, the number of lenses of the first lens group is greater than the number of lenses of the second and third lens groups, and an optical axis distance between the fourth lens group and an image sensor is variable, and the total number of lenses of the first to fourth lens groups is nL, and the number of lens groups that move among the first to fourth lens groups is nMLG, and the mathematical expression: 2 < nL / nMLG < 3 can be satisfied.

[0008] According to an embodiment of the invention, the first lens group includes first to third lenses, the second lens may have a biconvex shape, and the third lens may have a biconcave shape. The second lens group includes fourth and fifth lenses, and the fourth lens may have a biconvex shape.

[0009] According to an embodiment of the invention, the third lens group includes sixth and seventh lenses, and the sixth lens may have a convex meniscus shape toward the image sensor. The seventh lens may have a concave shape on both sides.

[0010] According to an embodiment of the invention, the second lens group may have positive (+) refractive power, and the third lens group may have negative (-) refractive power. Each of the second to fourth lens groups may be movable along the optical axis. The number of lenses in the second lens group and the third lens group may be the same.

[0011] According to an embodiment of the invention, the number of lenses in the fourth lens group is 1, and the difference in absolute values ​​of the radii of curvature of the object-side surface and the sensor-side surface of the lenses in the first to fourth lens groups may have the largest value in the fourth lens group. The effective length of the lens in the fourth lens group may be the largest among the effective lengths of the lenses in the first to fourth lens groups. The absolute value of the focal length of the lenses in the first to fourth lens groups may be the largest in the first lens.

[0012] An optical system and a camera module according to an embodiment can have various magnifications and can have excellent optical characteristics when providing various magnifications. Specifically, the embodiment can have various magnifications by controlling the movement distance of each moving lens group and can provide an autofocus (AF) function for a subject. The optical system and camera module according to an embodiment can have multiple lens groups correct aberration characteristics or mutually complement aberration characteristics that change due to movement. Accordingly, the optical system according to the embodiment can minimize or prevent changes in chromatic aberration and aberration characteristics that occur when the magnification changes.

[0013] An optical system and a camera module according to an embodiment can control an effective focal length (EFL) by moving only some lens groups among a plurality of lens groups, and can minimize a moving distance of the moving lens group. Accordingly, the optical system can reduce a moving distance of the moving lens group according to a change in the operation mode, and can minimize power consumption required when the lens group is moved. In the optical system, at least one lens included in a fixed group and a moving group can have a non-circular shape. Accordingly, the optical system can reduce the height of the optical system while maintaining optical performance, and can secure a space for structurally arranging lens groups arranged between the plurality of lens groups.

[0014] The optical system and camera module according to the embodiment can adjust magnification by moving a lens group other than the first lens group adjacent to the subject among the plurality of lens groups. Accordingly, the optical system can maintain a constant TTL value even when the lens group moves according to the change in magnification. Accordingly, the optical system and the camera module including the optical system can be provided with a slimmer structure.

[0015] FIG. 1 is a configuration diagram of an optical system and a camera module having the same according to an embodiment of the invention.

[0016] Fig. 2 is an example of the operation of the first mode of the optical system of Fig. 1.

[0017] Figure 3 is an example of the operation of the third mode in the optical system of Figures 1 and 2.

[0018] FIG. 4 is an example of an optical system and a camera module having a reflective member according to an embodiment of the invention.

[0019] Figure 5 is a table of lens data of an optical system according to an embodiment of the invention.

[0020] Fig. 6 shows the aspherical coefficients of the lenses of the optical system of Fig. 1.

[0021] FIG. 7 is a graph of diffraction MTF in an optical system in wide mode according to an embodiment of the invention.

[0022] FIG. 8 is a graph of diffraction MTF in an optical system of middle mode according to an embodiment of the invention.

[0023] FIG. 9 is a graph of diffraction MTF in an optical system in tele mode according to an embodiment of the invention.

[0024] Fig. 10 is a graph showing the aberration characteristics in the optical system of the first mode of Fig. 2.

[0025] Fig. 11 is a graph showing the aberration characteristics in the optical system of the second mode (Middle mode) of Fig. 1.

[0026] Fig. 12 is a graph showing the aberration characteristics in the optical system of the third mode (tele mode) of Fig. 3.

[0027] FIG. 13 is a graph showing relative illumination according to positions in wide, middle, and tele modes according to an embodiment of the invention.

[0028] FIG. 14 is a drawing showing a camera module according to an embodiment of the invention applied to a mobile terminal.

[0029] FIG. 15 is a perspective view of a mobile body having a camera module according to an embodiment of the invention.

[0030] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. However, the technical idea of ​​the present invention is not limited to some of the embodiments described, but can be implemented in various different forms, and one or more of the components between the embodiments can be selectively combined or substituted within the scope of the technical idea of ​​the present invention. In addition, terms (including technical and scientific terms) used in the embodiments of the present invention can be interpreted as having a meaning that can be generally understood by a person having ordinary skill in the technical field to which the present invention pertains, unless explicitly and specifically defined and described, and terms commonly used, such as terms defined in a dictionary, can be interpreted in consideration of the contextual meaning of the related technology. The terminology used in the embodiments of the present invention is for the purpose of describing the embodiments and is not intended to limit the present invention.

[0031] In this specification, the singular may also include the plural unless specifically stated in the phrase, and when it is described as “A and (or at least one (or more) of B, C,” it may include one or more of all combinations that can be combined with A, B, and C. In addition, when describing components of embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only for distinguishing the components from other components, and are not limited by the nature, order, or sequence of the components. In addition, when it is described that a component is “connected,” “coupled,” or “connected” to another component, it may include not only cases where the component is directly connected, coupled, or connected to the other component, but also cases where the component is “connected,” “coupled,” or “connected” by another component between the component and the other component.

[0032] When it is described in the specification that each component is formed or arranged "above or below", above or below includes not only cases where the two components are in direct contact with each other, but also cases where one or more other components are formed or arranged between the two components. In addition, when expressed as "above or below", it can include the meaning of the downward direction as well as the upward direction based on one component.

[0033] In the specification, the convexity of the lens surface may mean that the lens surface of the vertex region or the paraxial region corresponding to the optical axis has a convex shape based on the optical axis, and the concaveity of the lens surface may mean that the lens surface of the vertex region or the paraxial region corresponding to the optical axis has a concave shape. In addition, the "object-side surface" may mean the surface of the lens facing the object side based on the optical axis, and the "sensor-side surface" may mean the surface of the lens facing the imaging surface (image sensor) based on the optical axis. In addition, the center thickness of the lens may mean the thickness of the lens in the optical axis direction. In addition, 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 of the effective area of ​​the lens through which incident light passes. In addition, the size of the effective diameter of the lens surface may have a measurement error of up to ±0.4 mm depending on the measurement method, etc.

[0034]

[0035] As shown in FIG. 1, the optical system (1000) according to an embodiment of the invention may include a plurality of lens groups. The plurality of lens groups may include at least three lens groups. Each of the plurality of lens groups includes at least one lens. The plurality of lens groups include first to fourth lens groups (LG1 to LG4). The optical system (1000) may include the first to fourth lens groups (LG1 to LG4) sequentially arranged along the optical axis (OA) from an object toward an image sensor (300).

[0036] The optical system (1000) may include n lenses, the nth lens may be the last lens, and the (n-1)th lens may be the lens closest to the last lens. The n is an integer greater than or equal to 7, for example, 7 to 9. Within the optical system (1000), the lenses may be defined as a lens unit (100).

[0037] Among the plurality of lens groups, at least one lens group may be a fixed lens group having a fixed position, and at least two lens groups may be variable lens groups having variable positions. For example, the first lens group (LG1) adjacent to the object is a fixed lens group, and at least two lens groups or all lens groups arranged between the first lens group (LG1) and the image sensor (300) are variable lens groups having variable positions. That is, the second to fourth lens groups (LG2-LG4) are variable lens groups. Here, the variable lens groups may be moved in the optical axis direction or returned to their original positions. By the lens groups that are moved, the optical system (1000) may provide a continuous zoom optical system having a wide mode, a middle mode, and a tele mode.

[0038] The moving distance of the above-mentioned moving lens groups can be set to less than 15 mm at the most, thereby reducing the power consumption of the driving unit. In addition, when in tele mode, the optical axis distance (DG12) between the first and second lens groups (LG1, LG2) can be set to 1 mm or less, for example, in the range of 0.1 mm to 1 mm, thereby increasing the moving distance of the second and third lens groups (LG2, LG3), thereby providing a high-magnification optical system.

[0039]

[0040] The number of lenses of each of the first lens group (LG1) and the second lens group (LG2) may be the same. The number of lenses of the first lens group (LG1) may be greater than the number of lenses of the third lens group (LG3). The number of lenses of the first lens group (LG1) may be greater than the number of lenses of the fourth lens group (LG4), for example, may be two times or more.

[0041] The number of lenses of each of the first lens group (LG1) may be 2 or more, and may range from 2 to 4, for example. The number of lenses of each of the first lens group (LG1) may be equal to the sum of the number of lenses of the second lens group (LG2) and the number of lenses of the fourth lens group (LG4). The number of lenses of each of the first lens group (LG1) may be equal to the sum of the number of lenses of the third lens group (LG3) and the number of lenses of the fourth lens group (LG4). By stacking these lens numbers, an optical system of a wide mode, a middle mode, and a tele mode can be provided, and a bright optical system with an F number in the range of 2 to 5.2 can be provided depending on the operation mode.

[0042]

[0043] At least one or all of the lenses of the first to fourth lens groups (LG1-LG4) may be made of plastic. In addition, the lenses in the movable lens groups (LG2, LG3, LG4) may be arranged of plastic to prevent an increase in power consumption of the driving member. As another example, each of the movable lens groups (LG2, LG3, LG4) may include a plastic lens and a glass lens. As another example, the lens closest to the object among the lenses of the fixed lens group (LG1) may be made of glass. As another example, the lens in the lens group closest to the image sensor may be made of glass. At least one or all of the lens surfaces of the lenses of the first to fourth lens groups (LG1-LG4) may have an aspherical shape on the optical axis. As another example, the lens closest to the object among the lenses of the first to fourth lens groups (LG1-LG4) may be a spherical lens.

[0044] The lenses having the above aspherical surface can prevent spherical aberration within the optical system (1000), and since aberration does not occur even when the effective diameter is increased, the camera module can be made smaller and lighter. The above aspherical lens can be made of glass mold or plastic material.

[0045]

[0046] The power of the first lens group (LG1) may have a sign opposite to that of the power of the second lens group (LG2). The power of the first lens group (LG1) may be negative, and the power of the second lens group (LG2) may be positive. The power of the third lens group (LG3) may have a sign opposite to that of the fourth lens group (LG4). The power of the third lens group (LG3) may be negative, and the power of the fourth lens group (LG4) may be positive. By setting the powers of the first to fourth lens groups (LG1-LG4), chromatic aberration can be compensated. The number of lenses having positive power among the lenses in the optical system (10000) may be greater than the number of lenses having negative power.

[0047]

[0048] The focal length of the first lens group (LG1) is FLG1, the focal length of the second lens group (LG2) is FLG2, and the condition of FLG2 < │FLG1│ can be satisfied. The focal length of the third lens group (LG3) is FLG3, and the focal length of the fourth lens group (LG4) is FLG4, and the condition of │FLG3│ < FLG4 can be satisfied. The absolute value of the focal length of the first lens group (LG1) whose position is fixed can be greater than the absolute value of the focal length of the second, third, and fourth lens groups (LG2, LG3, LG4) that are moved. The angle of view (FOV) can be adjusted by the power of the first to fourth lens groups (LG1-LG4).

[0049]

[0050] Within the first lens group (LG1), the first lens (101) closest to the object and the third lens (103) closest to the second lens group (LG2) may have opposite refractive powers. Accordingly, the first lens group (LG1) may mutually compensate for chromatic aberrations caused by the plurality of lenses included in the first lens group (LG1). For example, the first lens (101) may have positive power and the third lens (103) may have negative power.

[0051] Here, the Abbe number (Vd3) of the lens adjacent to the second lens group (LG2) within the first lens group (LG1), i.e., the third lens (103), may be less than 45, and the condition: 20 < Vd3 < 45 may be satisfied. By this condition, the first lens group (LG1) can disperse the incident light to the periphery of the second lens group (LG2).

[0052] The Abbe number (Vd5) of the lens adjacent to the third lens group (LG3) in the second lens group (LG2), that is, the fifth lens (105), can satisfy the condition: Vd5 < 35, for example, 15 < Vd5 < 35. According to this condition, the second lens group (LG2) can refract the incident light in the direction of the optical axis of the third lens group (LG3). The minimum optical axis spacing between the lens groups moving according to the change in zoom magnification can be set to 0.2 mm or more, and the maximum optical axis spacing can be set to 13 mm or less.

[0053] The Abbe number (Vd8) of the lens adjacent to the image sensor (300) within the fourth lens group (LG4), i.e., the eighth lens (108), can satisfy the condition: 35 < Vd8, for example, 35 < Vd8 < 70. By this condition, the fourth lens group (LG4) can refract incident light to the entire area of ​​the image sensor (300) by the Abbe number and the lens shape.

[0054] Each of the first, second, and third lens groups (LG1, LG2, and LG3) may include lenses having refractive powers of opposite signs. Accordingly, the first, second, and third lens groups (LG1, LG2, and LG3) may mutually compensate for chromatic aberrations caused by the lenses. The sign of the refractive power of the lens of the fourth lens group (LG4) may be opposite to the sign of the refractive power of the n-1th lens. Accordingly, the third and fourth lens groups (LG3, LG4) may mutually compensate for chromatic aberrations caused by the lenses. Due to the difference in the signs of the refractive powers of the lenses, changes in chromatic aberration due to zooming can be minimized.

[0055]

[0056] The average refractive index of the lenses in the first lens group (LG1) is LG1_Nd, the average refractive index of the lenses in the second lens group (LG2) is LG2_Nd, the average refractive index of the lenses in the third lens group (LG3) is LG3_Nd, and the average refractive index of the lenses in the fourth lens group (LG4) is LG4_Nd, and the following conditions can be satisfied.

[0057] Condition 1: 1.56 < LG1_Nd < 1.62

[0058] Condition 2: 1.56 < LG2_Nd < 1.62

[0059] Condition 3: LG1_Nd < LG3_Nd < 1.7

[0060] Condition: LG4_Nd < 1.58 or 1.5 < LG4_Nd < 1.58

[0061] Under these conditions, the lenses of the first to fourth lens groups (LG1 to LG4) can refract the incident light to the center and periphery of the image sensor (300). The fourth lens group (LG4) can play a role in controlling the chief ray angle (CRA). In detail, the CRA of the optical system (1000) according to the embodiment can have a deviation of less than about 20 degrees, and the last eighth lens (108) can correct the chief ray angle (CRA) of the light incident on the image sensor (300) to be close to 0 degrees. Accordingly, the peripheral light quantity ratio of the optical system can be secured.

[0062]

[0063] When the sum of the refractive indices of the lenses in the above optical system (1000) is ∑Nd and the sum of the Abbe numbers is ∑Vd, the following conditions can be satisfied.

[0064] Condition 1: 12 < ∑Nd < 15

[0065] Condition 2: 260 < ∑Vd < 320

[0066] By adjusting the refractive index and Abbe number of the lenses in the optical system (1000), aberration can be controlled. Among the lenses in the optical system (1000), the lens having the maximum Abbe number can be positioned in the first, second, and fourth lens groups (LG1, LG2, LG4). Among the lenses in the optical system (1000), the lens having the maximum refractive index can be positioned in the first and third lens groups (LG1, LG3). In the optical system, there are three or more lenses having an Abbe number exceeding 45, and there are three or more lenses having a refractive index exceeding 1.6, and the color dispersion of light incident by these lenses can be controlled.

[0067]

[0068] Each of the lenses of the optical system (1000) may include an effective area and an ineffective area. The effective area may be an area through which light incident on each of the lenses passes. That is, the effective area may be defined as an effective area or effective diameter through which the incident light is refracted to implement optical characteristics. The ineffective area may be arranged around the periphery of the effective area. The ineffective area may be an area through which effective light is not incident from the plurality of lenses. That is, the ineffective area may be an area unrelated to the optical characteristics. In addition, an end of the ineffective area may be an area fixed to a lens barrel (not shown) that accommodates the lens.

[0069]

[0070] The average effective length of the lenses of the lens unit (100) can be provided as 7 mm or less, for example, in the range of 5 mm to 7 mm. Here, the effective length of each lens can be the average of the effective lengths of the object-side surface and the sensor-side surface of each lens. Within the first and second lens groups (LG1 and LG2), the maximum effective length of the object-side surface (S1) of the first lens (101) can be greater than the effective length of the object-side surfaces (S3 and S5) of the second and third lenses (102 and 103). Accordingly, the amount of light incident through the first lens (101) can be increased.

[0071] The maximum effective length of the object-side surface (S1) of the first lens (101) within the first and fourth lens groups (LG1, LG4) may be provided to be smaller than the maximum effective length of the sensor-side surface (S16) of the last lens (108). Accordingly, the last lens (108) can refract incident light to the entire area of ​​the image sensor (300). The number of lenses having an effective length greater than the average of the effective lengths of the first lenses (101) is two or less, for example, one. That is, the effective length of the n-th lens may be greater than the effective length of the first lens (101). That is, the invention can minimize the effective lengths of the lenses of the first and second lens groups (LG1, LG2) which are difficult to manufacture.

[0072]

[0073] One or more lenses in the optical system (1000) may have different effective lengths in a first direction (X) and a second direction (Y) perpendicular to the optical axis (OA). The first and second directions (X, Y) may be perpendicular to each other. The lenses having different effective lengths in the first and second directions (X, Y) may have a non-circular shape, and for example, the effective length in the second direction (Y) may be smaller than the effective length in the first direction (X). The second direction (Y) may be a direction perpendicular to the thickness direction or the display surface of a device having a camera module, for example, a portable terminal.

[0074] At least one of the lenses of the first lens group (LG1) may have different effective lengths on the object-side surface and / or the sensor-side surface, and the effective length in the second direction (Y) may be smaller than the effective length in the first direction (X). At least one of the lenses of the fourth lens group (LG4) may have different effective lengths on the object-side surface and / or the sensor-side surface, and the effective length in the second direction (Y) may be smaller than the effective length in the first direction (X).

[0075] In detail, the first lens (108) within the lens unit (100) may have an effective length in the first direction (X) that is greater than the effective length in the second direction (Y). At least one of the second and third lenses (102, 103) may have an effective length in the first direction (X) that is greater than the effective length in the second direction (Y). At least one or both of the eighth lenses (108) may have an effective length in the first direction (X) that is greater than the effective length in the second direction (Y).

[0076] When the lengths of the first and second directions (X, Y) of the object-side surface (CAm1) of the m-th lens are different, the maximum effective length in the first direction (X) is CAm1x, and the minimum effective length in the second direction (Y) is CAm1y, then the condition of the formula: 0.55 < CAm1y / CAm1x < 0.98 can be satisfied, and m can be the 1st, 2nd, 3rd, and 8th lenses. When the lengths of the first and second directions (X, Y) of the sensor-side surface (CAm2) of the m-th lens are different, the maximum effective length in the first direction (X) is CAm2x, and the minimum effective length in the second direction (Y) is CAm2y, then the condition of the formula: 0.55 < CAm2y / CAm2x < 0.98 can be satisfied, and m can be the 1st, 2nd, 3rd, and 8th lenses. If the value of the formula in the effective length of the object-side or sensor-side surface of the m-th lens is less than 0.55, it is difficult to manufacture the object-side or sensor-side surface of the m-th lens in a non-circular shape and it is difficult to control the distribution of the incident light, and if it exceeds 0.98, the size reduction in the second direction of the optical system may be minimal.

[0077] An optical system (1000) according to an embodiment can have improved assembly properties by non-circular lens(es) and a mechanically stable shape. In addition, the optical system (1000) can significantly reduce the moving distance of a moving lens group and provide various magnifications. In addition, since lenses having a large effective length in the second direction (Y) are provided in a shape in which both sides in the second direction (Y) are cut off, the height or thickness of the optical system (1000) and the camera module in the second direction (Y) can be reduced. Accordingly, an increase in the thickness of a device having a slim optical system (1000) and a camera module can be suppressed.

[0078]

[0079] Within the optical system (1000), the TTL (Total top length or Total track length) may be more than 4 times the ImgH, and preferably, the condition of 5 < TTL / ImgH < 12 or 6 < TTL / ImgH < 11 may be satisfied. The TTL is the distance from the center of the object-side surface (S1) of the first lens (101) to the surface of the image sensor (300) on the optical axis (OA). The ImgH is half of the maximum diagonal length of the effective area of ​​the image sensor (300). Within the optical system (1000), the effective focal length (EFL) is provided to be more than 10 mm and the diagonal field of view (FOV) is provided to be less than 45 degrees, so that it can be provided as a zoom optical system of a mobile terminal. Accordingly, the optical system (1000) can provide a high-resolution and high-magnification zoom optical system.

[0080]

[0081] The number of lenses in the lens unit (100) having an effective length greater than the maximum effective length of the image sensor (300) is less than 50%, and may be, for example, in the range of 10% to 40%. The lenses having an effective length greater than the maximum effective length of the image sensor (300) are the first and eighth lenses (101, 108). The effective length of the first lens (101) closest to the object side in the lens unit (100) may be shorter than the effective length of the eighth lens (108) closest to the image sensor (300). In addition, the effective lengths of the lens arranged on the object side of the aperture stop (ST) and the lens arranged on the sensor side may be shorter than the diagonal length of the image sensor (300). The aperture (ST) may be arranged on the periphery of the sensor-side surface of the first lens group (LG1) or the periphery of the object-side surface of the second lens group (LG2). The above aperture may be arranged between the fixed lens group and the moving lens group. Alternatively, the aperture may be arranged around the sensor-side surface of the third lens (103) or the object-side surface of the fourth lens (104). The aperture may control the brightness of the optical system. By controlling the effective diameter size of each lens, the optical system (1000) may control the incident light to compensate for the deterioration of optical characteristics due to resolution and temperature change, and may improve chromatic aberration control characteristics. Here, the effective length of each lens is the average of the effective lengths of the object-side surface and the sensor-side surface in the first direction (X).

[0082]

[0083] In the optical axis (OA), the optical axis spacing between the first lens group (LG1) and the second lens group (LG2) can be defined as DG12, the optical axis spacing between the second lens group (LG2) and the third lens group (LG3) can be defined as DG23, and the optical axis spacing between the third lens group (LG3) and the fourth lens group (LG4) can be defined as DG34. In addition, the optical axis spacing between adjacent two lenses can be defined as CG1-CG7 from the first lens (101) to the eighth lens (108), so that CG3 is DG12, CG5 is DG23, and CG7 is DG34. The optical axis distance (DG12) between the first lens group (LG1) and the second lens group (LG2) in the optical axis (OA) may be the optical axis distance between the sensor-side surface (S6) of the lens closest to the sensor side among the lenses in the first lens group (LG1) and the object-side surface (S7) of the lens closest to the object among the lenses in the second lens group (LG2). The optical axis distance (DG3) between the first lens group (LG1) and the second lens group (LG2) may be greater than 0.2 mm. That is, in the tele mode, the minimum optical axis distance (DG12_Min) between the first and second lens groups (LG1, LG2) may satisfy the condition: 0.2 mm < DG12_Min < 1 mm.

[0084] Here, among the lens surfaces of the first lens group (LG1) and the second lens group (LG2), two surfaces facing each other, the sensor-side surface (S6) of the first lens group (LG1) may have a concave shape and the object-side surface (S7) of the second lens group (LG2) may have a convex shape on the optical axis (OA). Accordingly, in the tele mode, the sensor-side surface (S6) of the first lens group (LG1) and the object-side surface (S7) of the second lens group (LG2) may be pressed against each other to a distance of less than 1 mm. The first lens group (LG1) and the second lens group (LG2) may refract light emitted through the sensor-side surface of the first lens group (LG1) to the object-side surface of the second lens group (LG2) depending on the operation mode.

[0085] The optical axis spacing (DG34) between the third lens group (LG3) and the fourth lens group (LG4) in the optical axis (OA) may be the optical axis spacing between the sensor-side surface (S14) of the lens closest to the sensor side among the lenses in the third lens group (LG3) and the object-side surface (S15) of the lens closest to the object among the lenses in the fourth lens group (LG4). The optical axis spacing (DG34) between the third lens group (LG3) and the fourth lens group (LG4) may be greater than 0.2 mm. That is, in the wide mode, the minimum optical axis spacing (DG34_Min) between the third and fourth lens groups (LG3, LG4) may satisfy the condition: 0.6 mm < DG34_Min < 1 mm.

[0086]

[0087] The sum of the central thicknesses of the lenses of the lens unit (100) of the embodiment may be 16 mm or less, for example, in the range of 10 mm to 16 mm or in the range of 11 mm to 15 mm. The sum of the central gaps between the lenses on the optical axis (OA) is variable, and is at least 12 mm or more and in the range of 12 mm to 20 mm, and the maximum value (∑CG_Max) of the sum of the central gaps may be greater than the sum of the central thicknesses of the lenses. The sum of the central thicknesses of the lenses of the lens unit (100) of the embodiment is ∑CT, and when the sum of the central gaps between the lenses is ∑CG, ∑CT < ∑CG_Max can be satisfied. When the central gaps between the lenses are made larger than the central thicknesses of the lenses, the weight of the lenses of the moving group can be reduced, and an increase in power consumption of the driving member can be prevented.

[0088]

[0089] The optical system (1000) or camera module may include an image sensor (300). The image sensor (300) may detect light and convert it into an electrical signal. The image sensor (300) may detect light that sequentially passes through the lens unit (100). The image sensor (300) may include an element capable of detecting incident light, such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor).

[0090] The optical system (1000) or camera module may include an optical filter (500). The optical filter (500) may be disposed between the fourth lens group (LG4) and the image sensor (300). The optical filter (500) may be disposed between the lens closest to the sensor side among the lenses of the lens unit (100) and the image sensor (300). For example, the optical system (100) may be disposed between the last lens and the image sensor (300). A cover glass (not shown) is disposed between the optical filter (500) and the image sensor (300), and may protect the upper portion of the image sensor (192) and prevent a decrease in the reliability of the image sensor (192). The cover glass may be removed.

[0091] The optical filter (500) may include an infrared filter or an infrared cut-off filter (IR cut-off). The optical filter (500) may allow light of a set wavelength band to pass through and filter out light of a different wavelength band. When the optical filter (500) includes an infrared filter, it may block radiant heat emitted from external light from being transmitted to the image sensor (300). In addition, the optical filter (500) may transmit visible light and reflect infrared light.

[0092] The optical system (1000) according to the embodiment may include an aperture (ST). The aperture (ST) may control the amount of light incident on the optical system (1000). The aperture (ST) may be disposed between any two lenses in the lens unit (100). For example, the aperture (ST) may be disposed on the periphery between the third lens (103) and the fourth lens (104). As another example, the aperture (ST) may be a portion coated on the periphery of the sensor-side sixth surface (S6) of the third lens (103) or the object-side surface (S7) of the fourth lens (104) that functions as an aperture. In detail, the object-side surface or the sensor-side surface of one lens selected from among the lenses of the optical system (1000) may function as an aperture that controls the amount of light.

[0093] The optical axis distance between the above aperture (ST) and the image sensor (300) is SD, and the value of the SD may vary depending on the operating mode, for example, wide mode, middle mode, and tele mode. That is, the SD values ​​in wide mode, middle mode, and tele mode may be defined as SD1, SD2, and SD3, and the SD values ​​may satisfy the condition: SD1 < SD2 < SD3. In addition, the SD values ​​may satisfy the condition: (SD3-SD2) <(SD2- SD1).

[0094]

[0095] The optical system (1000) according to the embodiment may further include a reflective member (400) for changing the path of light, as shown in FIG. 4. The reflective member (400) may be implemented as a prism or reflective mirror that reflects incident light of the first lens group (LG1) toward the lenses. Hereinafter, the optical system according to each embodiment will be described in detail.

[0096]

[0097] FIG. 1 is a configuration diagram of an optical system and a camera module having the same according to an embodiment of the invention, FIG. 2 is an example of operation of a first mode of the optical system of FIG. 1, FIG. 3 is an example of operation of a third mode in the optical system of FIGS. 1 and 2, FIG. 4 is an example of a reflective member being arranged in the optical system of FIG. 1, FIG. 5 is a table of lens data of an optical system according to an embodiment of the invention, and FIG. 6 shows aspherical coefficients of lenses of the optical system of FIG. 1.

[0098] FIGS. 7 to 9 are graphs showing diffraction MTF in an optical system of wide, middle, and tele modes according to an embodiment of the invention, FIGS. 10 to 12 are graphs showing aberration characteristics in wide, middle, and tele modes of the optical system of the invention, and FIG. 13 is a graph showing relative illumination according to positions in wide, middle, and tele modes according to an embodiment of the invention.

[0099] Referring to FIGS. 1 to 5, an optical system (1000) according to an embodiment may include a plurality of lens groups, for example, first to fourth lens groups (LG1, LG2, LG3, LG4). The first to fourth lens groups (LG1, LG2, LG3, LG4) may include lens groups having fixed positions and movable lens groups. The first lens group (LG1) is a lens group having a fixed position, and the second lens group (LG2) to the fourth lens group (LG4) are lens groups having variable positions. The second lens group (LG2) may be arranged between the first lens group (LG1) and the third lens group (LG3), and the third lens group (LG3) may be arranged between the second lens group (LG2) and the fourth lens group (LG4). The first lens group (LG1) refracts incident light toward the second lens group (LG2), and the second lens group (LG2) moves along the optical axis (OA) to change the zoom magnification (e.g., focal length), and the third and fourth lens groups (LG3, LG4) move along the optical axis (OA) to adjust the focus position on the image surface of the image sensor (300).

[0100]

[0101] The absolute value of the focal length of the first lens group (LG1) may be greater than the absolute value of the focal lengths of the second and third lens groups (LG2, LG3). For example, the absolute value of the focal length of the first lens group (LG1) may be 1.5 times or more greater than the focal length of the second lens group (LG2). Accordingly, the first lens group (LG1) may disperse incident light. The focal length of the second lens group (LG2) may be smaller than the absolute value of the focal length of the third lens group (LG3). The focal length of the fourth lens group (LG4) may be smaller than the absolute value of the focal length of the first lens group (LG1) and greater than the absolute value of the focal length of the third lens group (LG3). The power of the first and third lens groups (LG1, LG3) may have negative power, and the power of the second and fourth lenses (LG2, LG4) may have positive power. The power is the reciprocal of the focal length value.

[0102]

[0103] The lens unit (100) may include the first to eighth lenses (101-108). The first to eighth lenses (101-108) and the image sensor (300) may be sequentially arranged along the optical axis (OA) of the optical system (1000). The first lens group (LG1) may include two or more lenses, for example, the first, second, and third lenses (101, 102, and 103). The second lens group (LG2) may include two or fewer lenses, for example, the fourth and fifth lenses (104 and 105). The third lens group (LG3) may include two or fewer lenses, for example, the sixth and seventh lenses (106 and 107). The fourth lens group (LG4) may include two or fewer lenses, for example, the eighth lens (108). The above first lens group (LG1) may be composed of three lenses, and the above fourth lens group (LG4) may be composed of one lens.

[0104] When the focal lengths of the first to fourth lens groups (LG1-LG4) are defined as FLG1, FLG2, FLG3, and FLG4, the following conditions can be satisfied.

[0105] Condition 1: FLG2 < │FLG1│ < FLG2*3

[0106] Condition 2: (FLG4 - │FLG3│) < (│FLG3│ - FLG2)

[0107] Condition 3: FLG4 < │FLG1│< (│FLG3│*2)

[0108] Since the first lens group (LG1) is fixed in position and the second to fourth lens groups (LG2-LG4) are movable in the direction of the optical axis (OA), the optical system (1000) can provide various magnifications by moving the lens groups. In addition, the eighth lens (108) of the fourth lens group (LG4) can control the incident angle of the chief ray to refract light parallel to the optical axis so that it is incident toward the image sensor (300).

[0109]

[0110] The center spacing between the first to third lenses (101, 102, 103) may be a fixed spacing depending on the operation mode described below. For example, the center spacing between the first and second lenses (101, 102) and the center spacing between the second and third lenses (102, 103) may not change depending on the operation mode and may have a constant spacing. The center spacing between the first and second lenses (101, 102) may be 0.3 mm or less. The center spacing between the second and third lenses (102, 103) may be larger than the center spacing between the first and second lenses (101, 102) and may be more than 0.3 mm and less than 1 mm. Here, the center spacing between the lenses may mean the optical axis spacing between adjacent lenses.

[0111] The fourth and fifth lenses (104, 105) may have a set spacing. In detail, the center spacing between adjacent lenses (104, 105) may be a fixed spacing according to an operation mode to be described later. The sixth and seventh lenses (106, 107) may have a set spacing. In detail, the center spacing between the sixth and seventh lenses (106, 107) may be a fixed spacing according to an operation mode to be described later. The center spacing (CG3) between the third and fourth lenses (103, 104) may vary depending on the operation mode. The center spacing (CG5) between the fifth and sixth lenses (105, 106) may vary depending on the operation mode. The optical axis spacing (BFL: Back focal length) between the eighth lens (108) and the image sensor (300) may vary depending on the operation mode. The above eighth lens (108) may have different spacings from the image sensor (300) or / and the optical filter (500) depending on the operating mode.

[0112]

[0113] The first lens (101) may have a positive refractive power on the optical axis (OA). The first lens (101) may include a plastic or glass material, and may be, for example, a plastic material. The first lens (101) may include a first surface (S1) on the object side and a second surface (S2) on the sensor side. 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 that is convex toward the object on the optical axis (OA). Alternatively, the first surface (S1) may have a concave shape, and the second surface (S2) may have a convex shape. Alternatively, the first surface (S1) may have a convex shape, and the second surface (S2) may have a convex shape. At least one or both of the first surface (S1) and the second surface (S2) may be aspherical. As shown in Fig. 6, the first surface (S1) and the second surface (S2) may have aspherical coefficients from the 4th to the 20th order. As another example, the first surface (S1) and the second surface (S2) may be spherical.

[0114] The maximum effective length (CA: Clear aperture) of the first lens (101) may be greater than the effective lengths of the second to seventh lenses (102-107). Accordingly, the first lens (101) may improve optical aberrations or control incident light. The first surface (S1) and the second surface (S2) may be provided without critical points from the optical axis to the end of the effective area.

[0115]

[0116] The second lens (102) may have positive (+) or negative (-) refractive power on the optical axis (OA), for example, may have positive refractive power. The second lens (102) may include a plastic or glass material, for example, may be a plastic material. The object-side third surface (S3) of the second lens (102) may have a convex shape, and the sensor-side fourth surface (S4) may have a convex shape. The third surface (S3) and the fourth surface (S4) on the optical axis (OA) may have convex shapes. Alternatively, the second lens (102) may have concave shapes on both sides. Alternatively, the third surface (S3) may have a concave shape, and the fourth surface (S4) may have a convex shape. Alternatively, the third surface (S3) may have a convex shape, and the fourth surface (S4) may have a convex shape. At least one or both of the third surface (S3) and the fourth surface (S4) of the second lens (102) may be aspherical. As shown in FIG. 6, the third surface (S3) and the fourth surface (S4) may have aspherical coefficients ranging from the 4th to the 20th order.

[0117]

[0118] The third lens (103) may have a refractive power of a sign opposite to that of the first lens (101) on the optical axis (OA). That is, the third lens (103) may have a negative refractive power. The third lens (103) may include a plastic or glass material, and may be, for example, a plastic material.

[0119] The third lens (103) may have a concave shape on the object-side fifth surface (S5) and a concave shape on the sensor-side sixth surface (S6). The third lens (103) may have concave shapes on both sides. Alternatively, the fifth surface (S5) may have a convex shape and the sixth surface (S6) may have a concave shape. Alternatively, the fifth surface (S5) may have a convex shape and the sixth surface (S6) may have a convex shape. At least one or both of the fifth surface (S5) and the sixth surface (S6) of the third lens (103) may be aspherical. As shown in FIG. 6, the fifth surface (S5) and the sixth surface (S6) of the third lens (103) may have aspherical coefficients of the 4th to 20th orders.

[0120] The third lens (103) can compensate for chromatic aberration occurring in the second lens (102). The refractive index of the second lens (102) is arranged to be greater than the refractive indices of the first and third lenses (101, 103), thereby dispersing the incident light. Accordingly, since the first lens group (LG1) controls the dispersion of the light provided to the second lens group (LG2), an increase in the lens size of the second lens group (LG2) can be suppressed.

[0121]

[0122] The fourth lens (104) may have a positive (+) refractive power on the optical axis (OA). The fourth lens (104) may include a plastic or glass material, for example, may be a plastic material, and may have a refractive index of less than 1.6. The fourth lens (104) includes a seventh surface (S7) on the object side and an eighth surface (S8) on the sensor side, and the seventh surface (S7) may have a convex shape on the optical axis, and the eighth surface (S8) may have a convex shape. That is, the fourth lens (104) may have a shape in which both sides are convex on the optical axis (OA). Alternatively, the seventh surface (S7) may be concave on the optical axis (OA), and the eighth surface (S8) may be convex on the optical axis (OA). At least one or both of the seventh surface (S7) and the eighth surface (S8) of the fourth lens (104) may be aspherical. As shown in FIG. 6, the seventh surface (S7) and the eighth surface (S8) of the fourth lens (104) may have aspherical coefficients ranging from the 4th to the 20th order.

[0123]

[0124] The fifth lens (105) may have positive (+) or negative (-) refractive power on the optical axis (OA), for example, may have negative refractive power. The fifth lens (105) may include a plastic or glass material, for example, may be a plastic material. The fifth lens (105) may include a ninth surface (S9) on the object side and a tenth surface (S10) on the sensor side. The ninth surface (S9) may have a concave shape on the optical axis (OA), and the tenth surface (S10) may have a convex shape. That is, the fifth lens (105) may have a meniscus shape that is convex toward the sensor on the optical axis (OA). At least one or both of the ninth surface (S9) and the tenth surface (S10) may be aspherical. As shown in FIG. 6, the 9th and 10th surfaces (S9, S10) may have aspherical coefficients from the 4th to the 20th order. As another example, the 9th surface (S9) and the 10th surface (S10) may be spherical. As another example, the 9th surface (S9) of the 5th lens (105) may have a convex shape in the optical axis (OA), and the 10th surface (S10) may have a concave shape in the optical axis (OA). Alternatively, the 9th surface (S9) may have a concave shape in the optical axis (OA), and the 10th surface (S10) may have a concave shape in the optical axis (OA). Alternatively, the 9th surface (S9) may have a convex shape in the optical axis (OA), and the 10th surface (S10) may have a convex shape in the optical axis (OA).

[0125]

[0126] The third lens (103) may have a concave shape on both sides, and the fourth lens (104) may have a convex shape on both sides. When the fourth lens (104) is adjacent to the first lens group (LG1) along the optical axis (OA), the gap between the third and fourth lenses (103, 104) may be reduced. The center thickness (CT4) of the fourth lens (104) may be thicker than the edge thickness. The center thickness (CT5) of the fifth lens (105) may be thinner than the edge thickness. Accordingly, the gap between the eighth and ninth surfaces (S8, S9) may be reduced by the convex eighth surface (S8) of the fourth lens (104) and the concave ninth surface (S9) of the fifth lens (105).

[0127] The Abbe number (Vd4) of the fourth lens (104) may be greater than the Abbe numbers of the second, third, and fifth lenses (102, 103, and 105). The Abbe number (Vd4) of the fourth lens (104) may be greater than the Abbe numbers of the sixth and seventh lenses (106, and 107). The difference in the Abbe numbers between the fourth lens (104) and the fifth lens (105) may be greater than 20. Accordingly, the second lens group (LG2) can minimize changes in chromatic aberration caused by positions that change according to changes in the operation mode.

[0128]

[0129] The sixth lens (106) may have positive (+) or negative (-) refractive power on the optical axis (OA), for example, may have positive refractive power. The sixth lens (106) may include a plastic or glass material, for example, may be a plastic material. The sixth lens (106) may include an eleventh surface (S11) on the object side and a twelfth surface (S12) on the sensor side. The eleventh surface (S11) may have a concave shape on the optical axis (OA), and the twelfth surface (S12) may have a convex shape. That is, the sixth lens (106) may have a meniscus shape that is convex toward the sensor on the optical axis (OA). Alternatively, the eleventh surface (S11) may have a convex shape on the optical axis (OA), and the twelfth surface (S12) may have a concave shape on the optical axis (OA). Alternatively, the eleventh surface (S11) may have a concave shape in the optical axis (OA), and the twelfth surface (S12) may have a concave shape in the optical axis (OA). Alternatively, the eleventh surface (S11) may have a convex shape in the optical axis (OA), and the twelfth surface (S12) may have a convex shape in the optical axis (OA).

[0130] At least one or both of the eleventh surface (S11) and the twelfth surface (S12) of the sixth lens (106) may be aspherical or spherical. As shown in FIG. 6, the eleventh and twelfth surfaces (S11, S12) may have aspherical coefficients from the fourth to the twentieth order. The eleventh surface (S11) and the twelfth surface (S12) may be provided without a critical point from the optical axis to the end of the effective area.

[0131]

[0132] The seventh lens (107) may have positive (+) or negative (-) refractive power on the optical axis (OA), and may have negative refractive power. The refractive power of the seventh lens (107) has a sign opposite to the sign of the refractive power of the sixth lens (106), so that chromatic aberration can be improved. The seventh lens (107) may include a plastic or glass material, and may be, for example, a plastic material.

[0133] The seventh lens (107) may include a 13th surface (S13) on the object side and a 14th surface (S14) on the sensor side. The 13th surface (S13) may have a concave shape on the optical axis (OA), and the 14th surface (S14) may have a concave shape. That is, the seventh lens (107) may have a concave shape on both sides on the optical axis (OA). As another example, the 13th surface (S13) may have a convex shape, and the 14th surface (S14) may have a concave shape. Alternatively, the 13th surface (S13) may have a concave shape, and the 14th surface (S14) may have a convex shape on the optical axis (OA). In contrast, the 13th surface (S13) may have a convex shape, and the 14th surface (S14) may have a convex shape.

[0134] At least one or both of the 13th surface (S13) and the 14th surface (S12) of the 7th lens (107) may be aspherical. As shown in FIG. 6, the 13th and 14th surfaces (S13, S14) may have aspherical coefficients from the 4th to the 20th order. As another example, the 13th surface (S13) and the 14th surface (S12) may be spherical. At least one of the 13th surface (S13) and the 14th surface (S14) may be provided without at least one critical point.

[0135]

[0136] The eighth lens (108) may have positive or negative refractive power on the optical axis (OA), for example, may have positive refractive power. The eighth lens (108) may include a plastic or glass material, for example, may be a plastic material. The eighth lens (108) may include a fifteenth surface (S15) on the object side and a sixteenth surface (S16) on the sensor side. On the optical axis (OA), the fifteenth surface (S15) may have a concave shape, and the sixteenth surface (S16) may have a convex shape. That is, the eighth lens (108) may have a convex meniscus shape toward the sensor on the optical axis (OA). Alternatively, the eighth lens (108) may have a concave shape, and the sixteenth surface (S16) may have a convex shape. In contrast, the eighth lens (108) may have a convex shape, and the sixteenth surface (S16) may have a concave shape.

[0137] At least one or both of the 15th surface (S15) and the 16th surface (S16) of the 8th lens (108) may be aspherical. As shown in FIG. 6, the 15th and 16th surfaces (S16, S17) may have aspherical coefficients from the 4th to the 20th order. As another example, the 15th surface (S15) and the 16th surface (S16) may be spherical. The 16th surface (S16) may have a critical point. The critical point is a point where the trend of the Sag value changes. That is, the critical point is a point where the Sag value increases and then decreases on the lens surface, or a point where the Sag value decreases and then increases. The Sag value is the optical axis distance between a straight line perpendicular to the center of each lens surface and the lens surface, and the Sag value has a positive value at a position located on the sensor side relative to the center of each lens surface, and has a negative value at a position located on the object side relative to the center of each lens surface.

[0138]

[0139] The effective length of the above-mentioned eighth lens (108) is provided to be longer than the effective length of the seventh lens (107), so that the incident light can be refracted to the periphery of the image sensor (300). The sixth lens (106) and the eighth lens (108) can control chromatic aberration when the Abbe number difference is set to be greater than 20, for example, 30 or more. Accordingly, the third lens group (LG3) can minimize the chromatic aberration change caused by the position changing according to the mode change and perform an achromatic function. The fourth lens group (LG4) can perform a function of controlling the chief ray angle (CRA). In detail, the CRA of the optical system (1000) according to the embodiment may be less than about 20 degrees, and the eighth lens (108) of the fourth lens group (LG4) may correct the chief ray angle (CRA) of light incident on the image sensor (300) according to each operation mode.

[0140]

[0141] The camera module can move at least one or all of the second to fourth lens groups (LG2, LG3, LG4) among the plurality of lens groups (LG1, LG2, LG3, LG4) included in the optical system (1000) toward the object side or the sensor side along the optical axis (OA). As shown in Fig. 4, the camera module can include a plurality of driving members connected to the optical system (1000). The plurality of driving members are arranged on the outer side of each of the second to fourth lens groups (LG2-LG4) and can move the second to fourth lens groups (LG2, LG3, LG4) in the direction of the optical axis (OA) according to the operation mode.

[0142] The above operation mode may include a first mode moving at a first magnification as shown in FIG. 2, and a third mode operating at a second magnification different from the first magnification as shown in FIG. 3. At this time, the second magnification may be greater than the first magnification. In addition, the operation mode may include a second mode having a magnification between the first and third modes as shown in FIG. 1. Here, the first magnification may be the lowest magnification of the optical system (1000), and the second magnification may be the highest magnification of the optical system (1000). The first magnification may be about 1.5 magnification or more, for example, 1.5 to about 5 magnification, the second magnification may be about 6 to about 11 magnification, and the third magnification may be about 4 to about 6 magnification between the first and second magnifications. The first mode may be a wide mode, the second mode may be a middle mode, and the third mode may be a tele mode.

[0143] Each of the above driving members can move (M1, M2, M3) each of the second, third, and fourth lens groups (LG2, LG3, LG4) or operate them in an initial mode according to one operation mode selected from the first to third modes. In detail, each of the plurality of driving members is connected to the second lens group (LG2), the third lens group (LG3), and the fourth lens group (LG4), and can move each of the second lens group (LG2), the third lens group (LG3), and the fourth lens group (LG4) according to the operation mode. The initial mode may be any one of the first, second, and third modes, and may be, for example, the second mode or the middle mode. For example, in the first mode, each of the second lens group (LG2) to the fourth lens group (LG4) may be positioned at a position defined as a first position (Position 1). In the second mode, each of the second lens group (LG2) to the fourth lens group (LG4) may be positioned at a second position (Position 2) defined as closer to the object than the first position. In the third mode, each of the second lens group (LG2) to the fourth lens group (LG4) may be positioned at a third position (Position 3) defined as closer to the sensor than the first position. The first position may be an area between the second and third positions.

[0144] The first position at which the second lens group (LG2) is positioned in the first mode may be an area between the second and third positions at which the second lens group (LG2) is positioned in the second and third modes. The first position at which the third lens group (LG3) is positioned in the first mode may be an area between the second and third positions at which the third lens group (LG3) is positioned in the second and third modes. The first position at which the fourth lens group (LG4) is positioned in the first mode may be an area between the second and third positions at which the fourth lens group (LG4) is positioned in the second and third modes.

[0145]

[0146] Depending on the operation mode, at least one of the second lens group (LG2) to the fourth lens group (LG4) can move along the optical axis, and the first lens group (LG1) can be arranged at a fixed position. Depending on the operation mode, the second lens group (LG2) can move (M1), and the first lens group (LG1) can be arranged at a fixed position. Depending on the operation mode, the third lens group (LG3) can move (M2), and the first lens group (LG1) can be arranged at a fixed position. Depending on the operation mode, the fourth lens group (LG4) can move (M3), and the first lens group (LG1) can be arranged at a fixed position.

[0147] In each of the first position, the second position, and the third position according to the operation mode, the first to fourth lens groups (LG1, LG2, LG3, LG4) may have a set interval from the adjacent lens groups. Accordingly, the optical system (1000) may have a constant TTL and a variable BFL according to the operation mode, and the effective focal length and magnification of the optical system (1000) may be controlled by controlling the positions of some lens groups. The BFL is the optical axis interval between the last lens (108) and the image sensor (300).

[0148]

[0149] The first lens (101) may be arranged closest to an object among the plurality of lenses, and the eighth lens (108) may be arranged closest to the image sensor (300). For convenience of explanation, the center thickness of each of the first to eighth lenses (101-108) is CT1-CT8, the Abbe number is Vd1-Vd8, the refractive index is Nd1-Nd8, the average of the first direction (X) or the maximum effective length is CA1-CA8, and the focal length may be defined as F1-F8. The focal length of the optical system may be defined as FMd1, FMd2, and FMd3 in the first to third modes, that is, the wide mode (W), the middle mode (M), and the tele mode (T).

[0150] The effective length (CA8) of the eighth lens (108) is the maximum among the lenses, and the effective length (CA7) of the seventh lens (107) is the minimum among the lenses. The effective lengths (CA1, CA8) of the first and eighth lenses (101, 108) may be 6.5 mm or more. The effective length (CA7) of the seventh lens (107) may be less than 6 mm. The difference between the maximum effective length (CA_Min) and the minimum effective length (CA_Min) within the first surface (S1) to the sixteenth surface (S16) may exceed 1.5 mm. The condition: 1.5 mm < (CA_Max - CA_Min) < 3 mm may be satisfied.

[0151] The absolute value difference in the radius of curvature between the 15th surface (S15) and the 16th surface (S16) of the 8th lens (108) may be the largest among the differences in the radius of curvature (absolute value) between the object-side surface and the sensor-side surface of each lens, and may be, for example, 15 mm or more. The absolute value difference in the radius of curvature between the 7th surface (S7) and the 8th surface (S8) of the 4th lens (104) may be the smallest among the differences in the radius of curvature (absolute value) between the object-side surface and the sensor-side surface of each lens, and may be, for example, 4 mm or less. Since the 4th, 5th, and 6th lenses (104, 105, and 106) have center thicknesses (CT4, CT5, and CT6) of 1.5 mm or more and the radius of curvature (absolute value) of both sides of each lens has a difference of 25 mm or less, the light can be guided to the 8th lens (108) without significantly changing the path of the incident light.

[0152]

[0153] In the absolute value of the focal length, the focal length (F1) of the first lens (101) may be the largest among the lenses. In the focal lengths between adjacent two lenses, the absolute value difference between the focal lengths of the first and second lenses (101, 102) may be the largest, and the absolute value difference between the focal lengths of the fifth and sixth lenses (105, 106) may be the smallest. The focal lengths of the first to eighth lenses (101-108) may be defined as F1-F8, and may satisfy the following conditions.

[0154] Condition 1: │2*2 < F1

[0155] Condition 2: 0 < │F3│ - F4 < 5 mm

[0156] Condition 3: F6 < F2 < F8 < F1

[0157] Condition 4: (│F4│ + F5 + F6 + │F7│) < F1

[0158] Condition 5: (F2 + F8) < F1

[0159] Here, the average focal length of the moving lenses, for example, the fourth to eighth lenses (104-108), may be 15 mm or less, for example, in the range of 8 mm to 15 mm.

[0160]

[0161] The central thickness (CT6) of the sixth lens (10) may be the thickest among the central thicknesses of the lenses, and the central thickness (CT3) of the third lens (103) may be the largest. Since the third lens (103) has a concave shape on both sides and the thinnest central thickness (CT3), it can control the optical path according to the positional movement of the second lens group (LG2).

[0162] The center thicknesses (CT4, CT5, CT6) of the fourth to sixth lenses (104-106) may be 1.5 mm or more, and the center thicknesses (CT1, CT2, CT6, CT7, CT8) of the first, third, seventh, and eighth lenses (101, 103, 107, 108) may be less than 1.5 mm. The sum of the center thicknesses (CT4, CT5) of the fourth and fifth lenses (104, 105) may be greater than the sum of the center thicknesses (CT1, CT2, CT3) of the first to third lenses (101, 102, 103). Accordingly, the fourth and fifth lenses (104, 105) may guide light incident through the first lens group (LG1) to the fourth lens group (LG4).

[0163]

[0164] The center spacing between adjacent lens groups in the first mode (W), second mode (M), and third mode (T) are DG12, DG23, and DG34, and their relationship is as follows.

[0165] Mode 1: DG34 < DG23 < DG12

[0166] Mode 2: DG23 < DG12 < DG34

[0167] Mode 3: DG12 < DG23 < DG34

[0168] In the above 1st, 2nd, and 3rd modes, the maximum values ​​of DG12, DG23, and DG34 may be greater than the BFL. Here, the BFL is the optical axis distance from the sensor side of the 4th lens group (LG4) or the 8th lens (108) to the surface of the image sensor (300).

[0169] In the above 1st, 2nd, and 3rd modes, the maximum movement distance of the 2nd, 3rd, and 4th lens groups (LG2, LG3, LG4) is Max_mMd13, and can satisfy 5mm < Max_mMd13, and preferably, 5mm < Max_mMd13 < 11mm. Accordingly, the maximum movement distance for the zoom magnification can be reduced, thereby reducing the power consumption of the driving member. In the wide mode, the F number of the optical system (1000) provides a brightness of 4.5 or less, and may be in the range of 2.2 to 4.5. In the tele mode, the F number of the optical system (1000) provides a brightness of 5.2 or less, and may be in the range of 4 to 5.2.

[0170]

[0171] Tables 1, 2 and FIG. 5 are for the items of the mathematical formulas described above in the optical system (1000) of the embodiment, such as TTL (mm), BFL, effective focal length (F) (mm), focal length of each lens group, ImgH (mm), center thickness (CT) of each lens, center spacing (CG) between two adjacent lenses, focal lengths (F1, F2, F3, F4, F5, F6, F7, F8) (mm) of each of the first to eighth lenses, diagonal angle of view (FOV) (Degree), F number, etc.

[0172] Item Example Item Example FLG1 (mm) - 19.47 FLG4 (mm) 17.10 FLG2 (mm) 8.97 ImgH (mm) 3.528 FLG3 (mm) - 14.17 TTL (mm) 31.988

[0173] Table 2 shows the effective focal length (F), field of view (FOV), F number, entrance pupil size (EPD), SD, BFL, TD, etc. according to the first to third modes in the optical system according to the embodiment, where TD is the optical axis distance from the first surface (S1) to the sixteenth surface (S16). SD is the optical axis distance from the position of the aperture to the image sensor. In Table 2 below, SD may have a value smaller than TD depending on the operation mode, and the SD value may vary depending on the first to third modes.

[0174] Implementation Example 1 Mode (W) 2nd Mode (M) 3rd Mode (T) F (mm) 11.40 21.70 32.00 DG12 (mm) 9.000 3.39 20.500 DLG23 (mm) 1.288 1.815 3.785 DG34 (mm) 0.812 7.913 10.309 BFL (mm) 4.49 73.47 32.000 EPD (EPD1 / EPD2 / EPD3) 4.38 95.50 36.323 Fno (Fno1 / Fno2 / Fno3) 2.59 73.94 35.061 FOV (degrees) 36.6 48 19.20 113.303 SD (mm) 18.6 30 24.23 8 27.130 TD (mm)30.98830.98830.988

[0175] As shown in FIGS. 7 to 9, the optical system according to the embodiment may have MTF characteristics according to the first, second, and third modes (Wide, Mid, and Tele modes). In detail, FIG. 6 is a graph of the diffraction MTF characteristics of the optical system (1000) operating in the first to third modes, and it can be seen that the change in the position of defocusing according to the operating mode is not large.

[0176] FIGS. 10 to 12 are graphs measuring spherical aberration (Longitudinal Spherical Aberration), astigmatic field curves, and distortion from left to right in aberration graphs of an optical system according to an embodiment. In FIGS. 10 to 12, the X-axis may represent a focal length (mm) and a degree of distortion (%), and the Y-axis may represent the height of the image. In addition, the graph for spherical aberration is a graph for light in wavelength bands of about 435 nm, about 486 nm, about 546 nm, about 587 nm, and about 656 nm, and the graphs for astigmatic aberration and distortion aberration are graphs for light in wavelength bands of 546 nm. In the aberration diagram, it can be interpreted that the closer each curve is to the Y-axis, the better the aberration correction function, and it can be seen that the aberration change according to the operation mode (wide, mid, tele mode) is not large.

[0177] Fig. 13 is a graph showing relative illumination according to the relative sensor height (relative Fielded height) of the optical system of Figs. 1 to 3. As shown in Fig. 13, the relative illumination is highest in the center (0.0) field (Field) of the image sensor, and is 80% or more in the second and third modes (Middle mode, Tele mode) at the end (1.0) field, and the relative illumination is 50% or more in the first mode (Wide). The optical system (1000) according to the embodiment can have improved resolution and good optical performance not only in the center but also in the periphery of the field of view (FOV). The lens system according to the embodiment of the present invention can be configured with 7 or more lenses, for example, 7 to 9 lenses, so that spherical aberration, astigmatism, distortion, chromatic aberration, and coma can all be well corrected.

[0178]

[0179] The optical system (1000) according to the embodiment can satisfy at least one or two or more of the mathematical equations described below. Accordingly, the optical system (1000) according to the embodiment can effectively correct aberrations that change according to changes in the operation mode. The optical system (1000) can adjust the zoom magnification for a subject at various magnifications and can have a slim and compact structure.

[0180] Hereinafter, the optical axis spacing between adjacent two lenses can be defined as CG1-CG7 from the spacing between the first and second lenses to the spacing between the seventh and eighth lenses. The effective lengths of the object-side surface and the sensor-side surface of the first lens (101) to the major axis effective lengths of the object-side surface and the sensor-side surface of the eighth lens (108) can be defined as CA11, CA12 to CA81, CA82. The units of the thickness, spacing, radius of curvature, and effective length values ​​are mm. In addition, the effective length includes a circular or non-circular shape of the lens surface, and when the lens has a partially circular shape, it can be defined as the major axis effective length or the maximum effective length, and when the lens has a circular shape, it can be defined as the diameter or the effective diameter.

[0181] [Mathematical Formula 1] 2 < nL / nMLG < 3

[0182] In mathematical expression 1, nL is the number of lenses in the optical system, and nMLG is the number of lens groups that move within the optical system. That is, there are three groups of lenses that move within the optical system, and one group of lenses that is fixed. Here, 2 < nMLG < 4 can be satisfied.

[0183] [Mathematical Formula 2] 0.7 < CA11 / CA31 < 1.5

[0184] In mathematical expression 2, CA11 is the effective length or maximum effective length of the first surface (S1) of the first lens (101), and CA31 is the effective length or maximum effective length of the fifth surface (S5) of the third lens (103). The effective lengths of both lens surfaces in the first lens group can be set. When mathematical expression 2 is satisfied, the incident light of the optical system can be controlled. Preferably, 1 < CA11 / CA31 < 1.3 can be satisfied.

[0185] [Equation 3] 0.5 < CA11 / CA82 < 1.5

[0186] In mathematical expression 3, CA82 can set the effective length or maximum effective length of the 16th surface (S16) of the 8th lens (108). It can set the effective length or maximum effective length of the object-side surface of the lens closest to the object side and the sensor-side surface of the last lens in the optical system. When mathematical expression 3 is satisfied, the optical performance of the optical system can be maintained and a slim and compact structure can be provided. Preferably, 0.5 < CA11 / CA82 < 1 can be satisfied.

[0187] [Equation 4] 0.5 < CA62 / CA71 < 1.5

[0188] In mathematical expression 4, CA62 is the effective length of the sensor-side surface of the sixth lens (106), and CA71 is the effective length of the object-side surface of the seventh lens (107). When mathematical expression 4 is satisfied, light traveling to the third lens group (LG3) can be guided. When mathematical expression 4 is satisfied, deterioration of the optical performance of the optical system can be prevented. Preferably, 1 < CA62 / CA71 < 1.3 can be satisfied.

[0189] [Mathematical Formula 5] L1R2*LnR2 < 0

[0190] L1R1 is the radius of curvature of the object-side surface of the first lens (101), and LnR2 is the radius of curvature of the sensor-side surface of the last lens, that is, the sensor-side surface of the eighth lens. When the optical system satisfies mathematical expression 4, the gap between the first and second lens groups (LG1, LG2) can be adjusted, and the gap between the last lens and the image sensor (300) can be adjusted. Here, 0 < L1R2 and L8R2 < 0 can be satisfied.

[0191] [Equation 6] FLG1 < 0

[0192] In mathematical expression 6, FLG1 is the effective focal length (EFL) of the first lens group (LG1), and can have a value less than 0. FLG1 is the composite focal length of the first to third lenses. When mathematical expression 6 is satisfied, the optical aberration of the optical system, i.e., the optical aberration of the first lens group (LG1), can be improved.

[0193] [Mathematical Formula 7] 1 < LG4_CA / LG1_CA < 1.5

[0194] In mathematical expression 7, LG4_CA is the average effective length of the object-side surface and the sensor-side surface of the lenses of the fourth lens group, and LG1_CA is the average effective length of the object-side surface and the sensor-side surface of the lenses of the first lens group. That is, since the average effective length of the fourth lens group (LG4) is greater than the average effective length of the first lens group (LG1), the fourth lens group (LG4) can prevent the loss of light passing through the moving fourth lens group (LG4). Preferably, 1 < LG4_CA / LG1_CA < 1.3 can be satisfied.

[0195] [Equation 8] 3 < TTL / DLG1 < 10

[0196] In mathematical expression 8, DLG1 is the optical axis distance of the first lens group (LG1), for example, the optical axis distance from the center of the object-side surface of the first lens (101) to the center of the sensor-side surface of the third lens (103). For example, DLG1 means the distance in the optical axis (OA) of the first surface (S1) of the first lens (101) and the sixth surface (S6) of the third lens (103). TTL means the distance in the optical axis (OA) from the object-side first surface (S1) of the first lens (101) to the upper surface of the image sensor (300). When the optical system (1000) satisfies mathematical expression 8, the optical system (1000) has a relatively small TTL and can secure a peripheral light ratio. Preferably, 5 < TTL / DLG1 < 10 can be satisfied.

[0197] [Equation 9] 2 < TTL / EPD3 < 7

[0198] In mathematical expression 9, EPD3 refers to the size of the entrance pupil (EPD) of the optical system (1000) when operating in the third mode, i.e., Tele mode. When the optical system (1000) satisfies mathematical expression 9, the optical system (1000) can secure a bright image when operating in the third mode, and may be a minimum condition for securing an F number of 5.2 or less in Tele mode. Preferably, 3 < TTL / EPD3 < 6 can be satisfied.

[0199] [Equation 9-1] 6 < TTL / EPD1 < 9

[0200] [Equation 9-2] 4 < TTL / EPD2 < 7.5

[0201] In mathematical expressions 9-1 and 9-2, EPD1 is the size of the entrance pupil of the optical system in the first mode (Wide), and EPD2 is the size of the entrance pupil of the optical system in the second mode (Middle). When the optical system satisfies the above conditions, it can secure a bright image in each mode.

[0202]

[0203] [Equation 10] 2 < CT_Max / CT_Min < 6

[0204] In mathematical expression 10, CT_Max is the thickest thickness among the central thicknesses of the lenses, and CT_Min is the thinnest thickness among the central thicknesses of the lenses. If mathematical expression 10 is satisfied, the optical system aberration characteristics can be improved. Preferably, 3.3 < CT_Max / CT_Min < 5.3 can be satisfied.

[0205] [Mathematical Formula 11] 1 < CA_Max / CA_Min < 3

[0206] In mathematical expression 11, CA_Max is the largest effective length among each lens surface, and CA_Min is the smallest effective diameter among each lens surface. When mathematical expression 11 is satisfied, a camera module for a slim or compact structure can be provided while maintaining the optical performance of the optical system. Preferably, 1.2 < CA_Max / CA_Min < 1.8 can be satisfied.

[0207] [Equation 12] 0.1 < ΣCG_Wide / TTL < 0.8

[0208] In Equation 12, ΣCG_Wide is the sum of the center spacings between adjacent lenses in wide mode. When the optical system satisfies Equation 12, the movement distances of the second and third lens groups (LG2, LG3) and the center spacing between adjacent lenses within each lens group can be set according to each mode. Preferably, 0.2 < ΣCG / TTL < 0.6 can be satisfied.

[0209] [Equation 12-1] 0.3 < ΣCG_Mid / TTL < 0.6

[0210] [Equation 12-2] 0.3 < ΣCG_Tele / TTL < 0.65

[0211] ΣCG_Mid is the sum of the center spacings between adjacent lenses in the middle mode. ΣCG_Tele is the sum of the center spacings between adjacent lenses in the tele mode. Here, the condition: ΣCG_Wide < ΣCG_Mid < ΣCG_Tele can be satisfied.

[0212] [Mathematical Formula 13] 0.5 < DLG1 / DLG2 < 1

[0213] In mathematical expression 13, DLG1 is the optical axis distance of the first lens group (LG1), and DLG2 is the optical axis distance of the second lens group (LG2). By setting the optical axis distances of the first and second lens groups (LG1, LG2) in mathematical expression 13, TTL can be adjusted. Preferably, 0.7 < DLG1 / DLG2 < 1 can be satisfied.

[0214] [Equation 14] 2 < DLG1 / DLG4 < 5

[0215] In mathematical expression 14, DLG4 is the optical axis distance of the fourth lens group (LG4). Preferably, 2.3 < DLG1 / DLG4 < 4.3 can be satisfied. When the optical system (1000) according to the embodiment satisfies at least one of mathematical expressions 13 and 14, it has a relatively small TTL and can provide various magnifications according to at least three mode changes.

[0216]

[0217] [Equation 15] 0 < Max_CG3 / TTL < 0.5

[0218] In mathematical expression 15, the Max_CG2 is the maximum value of the optical axis spacing between the second lens (102) and the third lens (103) depending on the operation mode. When the optical system (1000) satisfies mathematical expression 15, the optical system (1000) has a relatively small TTL and can have improved optical characteristics by controlling stray light incident on the first lens group (LG1). Preferably, 0.1 < Min_CG3 / TTL < 0.4 can be satisfied.

[0219] [Equation 16] 3 < TTL / DLG2 < 10

[0220] Mathematical expression 16 sets the optical axis distance (DLG2) of the TTL and the second lens group (LG2), and when the optical system (1000) satisfies Mathematical expression 16, the optical system (1000) has a relatively small TTL and can improve chromatic aberration characteristics. Preferably, 4 < TTL / DLG2 < 8 can be satisfied.

[0221]

[0222] [Equation 17] 20 < |Vd4 - Vd5| < 50

[0223] In mathematical expression 17, Vd4 represents the Abbe number of the fourth lens (104), and Vd5 represents the Abbe number of the fifth lens (105). When the absolute value of the difference in Abbe numbers between the fourth and fifth lenses of the optical system (1000) according to the embodiment satisfies mathematical expression 17, the optical system (1000) can improve chromatic aberration characteristics. Preferably, Vd3 < Vd4 is satisfied, and 20 < Vd3 < 45 can be satisfied.

[0224] [Equation 18] 20 < |Vd8 - Vd6| < 50

[0225] In mathematical expression 18, Vd6 represents the Abbe number of the sixth lens, and Vd8 represents the Abbe number of the eighth lens. When the absolute value of the difference in Abbe numbers between the sixth and eighth lenses satisfies mathematical expression 18, the optical system (1000) can improve chromatic aberration characteristics. Preferably, Vd7 < Vd8 is satisfied, and Vd6 < 30 can be satisfied.

[0226] [Equation 18-1] 10 < |Vd8 - Vd7| < 30

[0227] [Equation 18-2] 0 < |Vd1 - Vd8| < 10

[0228]

[0229] [Equation 19] 1.6 < Nd2

[0230] In mathematical expression 19, Nd2 represents the refractive index of the second lens (101) at the d-line. When the optical system (1000) according to the embodiment satisfies mathematical expression 19, it can disperse the incident light and secure the effective area of ​​the lens placed on the sensor side relative to the second lens (102). Preferably, Nd1 < 1.6 can be satisfied.

[0231] [Equation 19-1] 1.5 < Nd1 < 1.6

[0232] [Equation 19-2] 1.6 < Nd5

[0233] [Equation 19-3] 1.6 < Nd6

[0234] [Equation 19-4] 1.5 < Nd8 < 1.6

[0235] The refractive index of the fifth and sixth lenses may exceed 1.6. Among the lenses, the number of lenses having a refractive index exceeding 1.62 may be three or more. Here, the product of the Abbe number of the first lens (101) and the Abbe number and refractive index of the eighth lens (108) is as follows.

[0236] Condition 1: 50 < Nd1*Vd1

[0237] Condition 2: 50< Nd8*Vd8

[0238]

[0239] [Mathematical Formula 20] 1 < L1R1 / L3R2 < 5

[0240] In mathematical expression 20, L1R1 denotes the radius of curvature of the object-side first surface (S1) of the first lens (101), and L3R2 denotes the radius of curvature of the sensor-side sixth surface (S6) of the third lens (103). When the optical system (1000) satisfies mathematical expression 20, the optical system (1000) can control stray light incident on the first lens group (LG1). Preferably, 2 < L1R1 / L3R2 < 4 can be satisfied. Since the third lens (103) has a concave sensor-side surface on the optical axis, the effective diameter of the fourth lens (104) can be suppressed from increasing.

[0241] [Equation 21] 2 < L1R1 / L4R1 < 6

[0242] In mathematical expression 21, L1R1 denotes the radius of curvature of the object-side first surface (S1) of the first lens (101), and L4R1 denotes the radius of curvature of the object-side seventh surface (S7) of the fourth lens (104). When the optical system (1000) according to the embodiment satisfies mathematical expression 21, the optical system (1000) can have good optical performance at various magnifications by setting the radius of curvature between the fixed lens group and the movable lens group. Preferably, 3 < L1R1 / L4R1 < 5 can be satisfied.

[0243] [Mathematical Formula 22] 1 < L3R2 / L4R1 < 3

[0244] In mathematical expression 22, L3R2 denotes the radius of curvature of the sixth surface (S6) on the sensor side of the third lens (103). When the optical system (1000) according to the embodiment satisfies mathematical expression 22, the refractive power of the second lens group (LG2) can be controlled, and the optical system (1000) can have good optical performance in the periphery of the field of view (FOV) when operating at various magnifications of at least three modes. Preferably, 1 < L3R2 / L4R1 < 2 can be satisfied.

[0245] [Equation 23] 2 < |L1R1 / L8R2| < 4

[0246] In mathematical expression 23, L8R2 represents the radius of curvature of the sensor-side 16th surface (S16) of the eighth lens (108). When the optical system (1000) satisfies mathematical expression 23, the optical system (1000) can control the refractive power of the first and eighth lenses (101, 108), thereby achieving good optical performance in the center and periphery of the field of view (FOV). Preferably, the condition: 5 mm < |L8R2| < L1R1 can be satisfied.

[0247]

[0248] [Equation 24] 0 < Md12_mLG2 / TTL < 0.5

[0249] In mathematical expression 24, Md12_mLG2 means the difference in the center spacing (unit: mm) after the movement of the second lens group (LG2) when changing from the second mode to the first mode, or from the first mode to the second mode. In detail, the Md12_mLG2 represents the movement distance of the second lens group (LG2) in the first and second modes, and means the difference value between the optical axis spacing between the first and second lens groups (LG1, LG2) in the first mode and the optical axis spacing between the first and second lens groups (LG1, LG2) in the second mode. When the optical system (1000) satisfies mathematical expression 24, the optical system (1000) can minimize the movement distance of the second lens group (LG2) when the magnification is changed, so that the optical system (1000) can have a slim structure. In addition, the movement distance can be minimized when controlling the position of the second lens group (LG2), thereby providing improved power consumption characteristics. Preferably, 0.1 < Md12_mLG2 / TTL < 0.2 can be satisfied.

[0250] [Equation 25] 0 < Md23_mLG2 / TTL < 0.5

[0251] In mathematical expression 25, Md23_mLG2 refers to the difference in the center spacing (unit: mm) after movement of the second lens group (LG2) when operating from the second mode to the third mode, or from the third mode to the second mode. Specifically, Md23_mLG2 refers to the difference value between the optical axis spacing between the first and second lens groups (LG1, LG2) in the second mode and the optical axis spacing between the first and second lens groups (LG1, LG2) in the third mode. The maximum movement distance of the second lens group (LG2) may be greater than the maximum movement distance of the third lens group (LG3). When the optical system (1000) according to the embodiment satisfies mathematical expression 25, the optical system (1000) can minimize the movement distance of the second lens group (LG2) when the magnification is changed, so that the optical system (1000) can have a slim structure. In addition, the movement distance can be minimized when controlling the position of the second lens group (LG2), thereby providing improved power consumption characteristics. 0 < Md23_mLG2 / TTL < 0.1 can be satisfied. In addition, the condition of Md23_mLG2 < Md12_mLG2 can be satisfied.

[0252] [Equation 26] 0.3 < Md12_mLG2 / DLG2 < 1.5

[0253] Mathematical expression 26 can set the movement distance of the second lens group (LG2) and the optical axis distance of the second lens group (LG2). When the optical system (1000) satisfies Mathematical expression 26, the optical system (1000) can minimize the movement distance of the second lens group (LG2) when the magnification is changed, so that the optical system (1000) can have a slim structure. In addition, the movement distance can be minimized when controlling the position of the second lens group (LG2), so that it can have improved power consumption characteristics. Preferably, 1 < Md12_mLG2 / DLG2 < 1.3 can be satisfied.

[0254] [Mathematical Formula 27] 1 < Md23_mLG4 / DLG4 < 3

[0255] In mathematical expression 27, Md23_mLG4 refers to the difference in the center spacing after the movement of the fourth lens group (LG4) when changing from the second mode to the third mode, or from the third mode to the second mode. When the optical system (1000) satisfies mathematical expression 27, the optical system (1000) can minimize the movement distance of the fourth lens group (LG4) when the magnification is changed, and can have a slim structure. In addition, since the movement distance can be minimized when controlling the position of the fourth lens group (LG4), it can have improved power consumption characteristics. Preferably, 1.5 < Md23_mLG4 / DLG4 < 2.5 can be satisfied.

[0256]

[0257] [Equation 28] 0 < DLG4 / Max_CG7 < 0.5

[0258] In mathematical expression 28, DLG4 is the optical axis distance of the fourth lens group, and Max_CG7 is the maximum optical axis distance between the third and fourth lens groups or the maximum optical axis distance between the seventh and eighth lenses. When mathematical expression 28 is satisfied, the optical system can move the fourth lens group (LG4) further than the optical axis distance of the fourth lens group along the distance between the third and fourth lens groups, and can adjust the screen focus position. Preferably, 0.1 < DLG4 / Max_CG7 < 0.3 can be satisfied.

[0259] [Equation 29] 1 < DLG3 / Max_CG5 < 2

[0260] In mathematical expression 29, DLG3 is the optical axis distance of the third lens group, and Max_CG5 is the maximum optical axis spacing between the second and third lens groups or the maximum optical axis spacing between the fifth and sixth lenses. When mathematical expression 29 is satisfied, the optical system can adjust the zoom magnification by allowing the second and third lens groups to move along the optical axis. Preferably, 1 < DLG3 / Max_CG4 < 1.5 can be satisfied.

[0261]

[0262] [Mathematical Formula 30] 3 < Md1(DG12 / DG23) < 9

[0263] In mathematical expression 30, Md1(DG12 / DG23) represents the ratio between the center spacing (DG12) between the first and second lens groups in the first mode and the center spacing (DG23) between the second and third lens groups. When the optical system (1000) according to the embodiment satisfies mathematical expression 30, the optical system (1000) may have improved optical characteristics at the first magnification. In detail, the optical system (1000) may have improved aberration characteristics at the first magnification and may improve optical performance at the center and periphery of the field of view (FOV). Preferably, 5 < Md1(DG12 / DG23) < 8 may be satisfied.

[0264] [Equation 31] 0 < Md3(DG12 / DG34) < 0.5

[0265] In mathematical expression 31, Md3(DG12 / DG34) represents the ratio between the center spacing (DG12) between the first and second lens groups in the third mode and the center spacing (DG34) between the third and fourth lens groups. When the optical system (1000) according to the embodiment satisfies mathematical expression 31, the optical system (1000) can have improved optical characteristics at the third magnification. In detail, the optical system (1000) can have improved aberration characteristics at the third magnification and improve the optical performance of the peripheral part of the field of view (FOV). Preferably, 0 < Md3(DG12 / DG34) < 0.2 can be satisfied.

[0266]

[0267] [Equation 32] 1 < DLG2 / DLG4 < 5

[0268] Mathematical expression 32 can set the optical axis distances (DLG2, DLG4) of the second and fourth lens groups (LG2, LG4). When mathematical expression 32 is satisfied, the center spacing between lenses in an optical system having a lens group with a movable last lens can be set, and the moving distance can be adjusted. Preferably, 2 < DLG2 / DLG4 < 4 can be satisfied.

[0269] [Equation 33] 1 < DLG3 / DLG4 < 5

[0270] Mathematical expression 33 can set the optical axis distances (DLG3, DLG4) of the third and fourth lens groups (LG3, LG4). When mathematical expression 33 is satisfied, the center spacing between lenses in an optical system having a lens group with a movable last lens can be set, and the moving distance can be adjusted. Preferably, 2 < DLG3 / DLG4 < 4.2 can be satisfied.

[0271] [Mathematical Formula 34] DLG4 < DLG1 < DLG2 < DLG3

[0272] Mathematical expression 34 can set the optical axis distances of the first to fourth lens groups. That is, by setting the optical axis distances of the second and third lens groups to be greater than the optical axis distances of the first and fourth lens groups, the influence of optical characteristics according to the adjustment of the zoom ratio can be reduced.

[0273]

[0274] [Equation 35] 0 < BFL2 / TTL < 0.5

[0275] [Equation 36] 0.2 < BFL3 / BFL1 < 0.7

[0276] [Equation 37] 0 < DLG4 / BFL3 < 1

[0277] Mathematical expressions 35 to 37 can move the last lens along the optical axis depending on the operating mode. In this structure, the BFL1 value in the first mode, the BFL2 value in the second mode, and the BFL3 value in the third mode can be set, and the relationship between the BFL values ​​and the optical axis distance (DLG4) of the TTL and fourth lens group can also be set.

[0278]

[0279] [Equation 38] 0 < CT3 / ET3 < 1

[0280] In mathematical expression 38, the center thickness (CT3) and edge thickness (ET3) of the third lens can be set. The third lens can be provided in a concave shape on both sides. Preferably, 0.2 < CT3 / ET3 < 0.5 can be satisfied.

[0281] [Equation 38-2] 1 < CT4 / ET4 < 5

[0282] In mathematical expression 38-1, the center thickness (CT4) and edge thickness (ET4) of the fourth lens can be set. The fourth lens can be provided in a biconvex shape, and the minimum optical axis distance between the third and fourth lenses can be set to less than 1 mm when the fourth lens moves in the optical axis direction. Preferably, 2 < CT4 / ET4 < 3 can be satisfied.

[0283] [Equation 38-3] 1 < CT8 / ET8 < 3

[0284] The center thickness (CT8) and edge thickness (ET8) of the eighth lens can be set. The eighth lens can be provided in a convex meniscus shape toward the sensor, and the minimum value of BFL can be set to 0.5 mm or more when the eighth lens moves in the optical axis direction. Preferably, 1.2 < CT8 / ET8 < 2.2 can be satisfied. Table 3 shows the edge thicknesses (ET1-ET8) of each lens.

[0285] ET valueET10.786ET21.567ET31.827ET41.078ET52.488ET62.443ET71.868ET80.735

[0286] [Mathematical Formula 39] 1mm < BFL_Min < 5mm

[0287] BFL_Min is the minimum optical axis distance between the last lens and the image sensor, which can secure space for installing optical filters, etc. Preferably, 1 mm < BFL_Min < 3 mm can be satisfied.

[0288]

[0289] [Equation 40] 30 < Aver_Vd < 50

[0290] In mathematical expression 40, Aver_Vd is the average Abbe number of the first to eighth lenses. When the optical system satisfies mathematical expression 40, the optical system (1000) can have improved aberration characteristics and resolution. Preferably, 30 < Aver_Vd < 38 can be satisfied.

[0291] [Equation 41] 1.5 < Aver_Nd < 1.8

[0292] In mathematical expression 40, Aver_Nd is the average refractive index of the first to eighth lenses. When the optical system satisfies mathematical expression 41, the optical system (1000) can have improved aberration characteristics and resolution. Preferably, 1.58 < Aver_Nd < 1.62 can be satisfied.

[0293] [Equation 41-1] 10 < ∑Vd / ∑Nd < 30

[0294] In mathematical expression 41-1, ²Vd means the sum of the Abbe numbers of each of the plurality of lenses. ²Nd means the sum of the refractive indices of each of the plurality of lenses. When the optical system (1000) according to the embodiment satisfies mathematical expression 41-1, the optical system (1000) can have improved aberration characteristics and resolution. Preferably, mathematical expression 41-1 can satisfy 19 < ∑Vd / ∑Nd < 27.

[0295]

[0296] [Equation 42] 1 < │ FLG1 / FLG2 │ < 3

[0297] In mathematical expression 42, FLG1 represents the effective focal length (EFL) of the first lens group (LG1), and FLG2 represents the effective focal length of the second lens group (LG2). FLG2 is the composite focal length of the fourth and fifth lenses. If mathematical expression 42 is satisfied, the size of the optical system, for example, the total track length (TTL), can be reduced. Preferably, 0 < FLG2 is satisfied. FLG3 is the composite focal length of the sixth and seventh lenses, and FLG3 < 0. FLG4 is the focal length of the fourth lens group or the eighth lens, and 0 < FLG4 < │FLG1│ can be satisfied.

[0298] [Mathematical Formula 43] 1 < FMd3 / FMd1 < 4

[0299] In mathematical expression 43, FMd1 is the effective focal length of the optical system in the first mode, and FMd3 is the effective focal length of the optical system in the third mode. Preferably, 1.5 < FMd3 / FMd1 < 2.5 can be satisfied. When the optical system satisfies mathematical expression 43, the effective focal length can be adjusted according to the first and third modes. The overall effective focal length according to the first to third modes can satisfy FMd1 < FMd2 < FMd3.

[0300] [Equation 44] 2 < FMd2 / EPD2 < 7

[0301] In mathematical expression 44, FMd2 is the effective focal length of the optical system in the second mode (Middle), and EPD2 refers to the size of the entrance pupil of the optical system (1000) in the second mode. When the optical system (1000) according to the embodiment satisfies mathematical expression 44, the optical system (1000) can secure a bright image when operating in the second mode. Preferably, 3 < FMd2 / EPD2 < 5 can be satisfied.

[0302] [Mathematical Formula 45] 1 < FMd1 / EPD1 < 4

[0303] In mathematical expression 34, FMd1 is the effective focal length of the optical system in the first mode (Wide), and EPD1 refers to the size of the entrance pupil of the optical system (1000) when operating in the first mode. When the optical system (1000) according to the embodiment satisfies mathematical expression 45, the optical system (1000) can secure a bright image when operating in the first mode. Preferably, 2 < FMd1 / EPD1 < 3 can be satisfied.

[0304] [Mathematical Formula 46] FMd1 < FMd2 < FMd3

[0305] In mathematical expression 46, FMd1, FMd2, and FMd3 represent the effective focal lengths of the optical system in the first, second, and third modes. The effective focal length in the third mode may be the largest, and the effective focal length in the first mode may be the smallest.

[0306] [Mathematical Formula 47] 1 < TTL / FMd2 < 2

[0307] Mathematical expression 47 can adjust TTL by comparing the effective focal length in TTL and the second mode. Preferably, 1.2 < TTL / FMd2 < 1.7 can be satisfied.

[0308] [Mathematical Formula 48] 1 < TTL / FMd1 < 5

[0309] Mathematical expression 47 can adjust TTL by comparing the effective focal length in TTL and the first mode. Preferably, 2 < TTL / FMd1 < 3.5 can be satisfied.

[0310]

[0311] [Equation 49] 1 < CA_Max / ImgH < 3

[0312] In mathematical expression 49, CA_Max refers to the largest effective length (CA) among the lens surfaces of the plurality of lenses included in the optical system (1000). ImgH refers to the distance from the 0 field area of ​​the image surface center of the image sensor (300) overlapping with the optical axis (OA) to the 1.0 field area of ​​the image sensor (300). The ImgH refers to half of the maximum diagonal length of the effective area of ​​the image sensor (300). When the optical system (1000) according to the embodiment satisfies mathematical expression 49, the optical system (1000) can be provided in a slim and compact manner. In addition, the optical system (1000) can implement high resolution and high image quality. The range of the ImgH is 2 mm or more, for example, 2 mm to 5 mm.

[0313] [Mathematical Formula 50] 5 < TTL / ImgH < 12

[0314] When the optical system (1000) satisfies mathematical expression 39, the optical system (1000) can have a smaller TTL, so that the optical system (1000) can be provided in a slim and compact manner. Preferably, it can be in the range of 7 < TTL / ImgH < 11.

[0315] [Mathematical Formula 51] 0.5 < BFL2 / ImgH < 1.5

[0316] [Equation 52] 0 < BFL3 / ImgH < 1

[0317] In mathematical expressions 51 and 52, the optical axis distance between the last lens and the image sensor in the second and third modes may be less than half the diagonal length of the image sensor. Accordingly, the screen focus position can be adjusted according to the movement of the fourth lens group.

[0318] [Mathematical Formula 53] 1 mm < EPD1 < EPD2 < EPD3 < 10 mm

[0319] The size of the entrance can be set according to the first to third modes.

[0320]

[0321] [Equation 53] 0 < Max_Distortion < 3

[0322] In mathematical expression 53, Max_Distortion means the maximum value or the maximum value of the distortion from the center (0.0F) of the image sensor to the diagonal end (1.0F) based on the optical characteristics detected by the image sensor (300). When the optical system (1000) satisfies mathematical expression 53, the optical system (1000) can improve the distortion characteristics and set conditions for image processing. Preferably, 0 < |Max_Distortion| < 1.5 can be satisfied. Table 4 is a table showing the distortion characteristics from the center (Dist F1) to the end (Dist F11) of the first to third modes.

[0323] Sensor heightWideMiddleTeleDist(F1)000Dist(F2)-0.00290.02770.0062Dist(F3)-0.01580.1 0380.0206Dist(F4)-0.04830.21230.0333Dist(F5)-0.10970.33930.0373Dist(F6)-0.20 430.47980.0326Dist(F7)-0.32550.63740.0245Dist(F8)-0.4840.81580.0155Dist(F9)- 0.67551.01210.0003Dist(F10)-0.89281.2205-0.0254Dist(F11)-1.12551.4374-0.0591

[0324] [Equation 55]

[0325] 8° < FOV3 < FOV2 < FOV1 < 45°

[0326] In mathematical expression 55, FOV (Field of view) means the angle of view (Degree) in the diagonal direction of the optical system (1000), FOV1 is the angle of view in the first mode, FOV2 is the angle of view in the second mode, and FOV3 represents the angle of view in the third mode, and can be set in the order of the angles of wide, middle, and tele modes depending on the operation mode. Preferably, 10° < FOV < 40° can be satisfied.

[0327]

[0328] [Equation 56]

[0329]

[0330] In mathematical expression 56, Z may represent Sag, which is the distance from an arbitrary position on an aspherical surface to the vertex of the aspherical surface in the direction of the optical axis. In addition, Y may represent the distance from an arbitrary position on the aspherical surface to the optical axis in the direction perpendicular to the optical axis. In addition, c may represent the curvature of the lens, and K may represent the conic constant. In addition, A, B, C, D, E, and F may represent aspheric constants from the 4th to the 14th order.

[0331]

[0332] The optical system (1000) according to the embodiment can satisfy at least one of the above-described mathematical expressions 1 to 55. Accordingly, the optical system (1000) and the camera module can have improved optical characteristics. Specifically, since the optical system (1000) satisfies at least one or two or more mathematical expressions of the above-described mathematical expressions 1 to 55, it can effectively correct optical characteristic degradation such as chromatic aberration, vignetting, diffraction effect, and deterioration of image quality in the periphery caused by movement of the lens group. In addition, the optical system (1000) according to the embodiment can significantly reduce the movement distance of the lens group and provide an autofocus (AF) function for various magnifications with excellent power consumption characteristics.

[0333] The optical system (1000) according to the embodiment can have improved assembly properties and a mechanically stable shape by satisfying at least one or more of the above mathematical expressions 1 to 55, and can be provided with a slim structure, so that the optical system (1000) and the camera module including the same can have a compact structure. Table 5 shows the result values ​​for the above mathematical expressions 1 to 28 in the optical system (1000) of the embodiment, and the optical system can satisfy at least one or two or more. Table 6 shows the values ​​of mathematical expressions 29 to 50, and it can be seen that the optical system satisfies at least one, two or more, or three or more of the mathematical expressions 29 to 55. Accordingly, the optical system (1000) can have good optical performance and excellent optical characteristics at the center and periphery of the field of view (FOV).

[0334] 수학식 값12 < nL / nMLG < 32.66720.7 < CA11 / CA31 < 1.51.14830.5 < CA11 / CA82 < 1.50.97540.5 < CA62 / CA71 < 1.51.1205L1R2*LnR2 < 0-263.7806FLG1 < 0-19.47171 < LG4_CA / LG1_CA < 1.51.1183 < TTL / DLG1 < 107.34192 < TTL / EPD3 < 75.059102 < CT_Max / CT_Min < 64.316111< CA_Max / CA_Min <31.412120.1 < ΣCG_Wide / TTL < 0.80.407130.5 < DLG1 / DLG2 < 10.920142 < DLG1 / DLG4 < 53.387150 < Max_CG3 / TTL < 0.50.281163 < TTL / DLG2 < 106.7531720 < |Vd4 - Vd5| <5034.0641820 < |Vd8 - Vd6| < 5036.470191.6 < Nd21.536201 < L1R1 / L3R2 < 52.775212 < L1R1 / L4R1 < 64.097221 < L3R2 / L4R1 < 31.477232 < |L1R1 / L8R2| < 42.814240 < Mode12_mLG2 / TTL < 0.50.175250 < Mode23_mLG2 / TTL < 0.50.090260.3 < Mode12_mLG2 / DLG2 < 1.51.184271 < Mode23_mLG4 / DLG4 < 31.862280 <DLG4 / Max_CG7 < 0.50.125

[0335] <h2 style=";text-align:left;direction:ltr">수학식 값291 < DLG3 / Max_CG5 < 21.324303< Md1 (DG12 / DG23) < 96.987310< Md3 (DG12 / DG34) < 0.50.049321 < DLG2 / DLG4 < 53.681331 < DLG3 / DLG4 < 53.89634DLG4 < DLG1 < DLG2 < DLG3만족350 < BFL2 / TTL < 0.50.109360.2 < BFL3 / BFL1 < 0.70.445370 < DLG4 / BFL3 < 10.643380 < CT3 / ET3 < 10.380391 < BFL_Min < 52.0004030 < Aver_Vd < 5037.465411.5 < Aver_Nd < 1.81.594421 < 쥅 FLG1 / FLG2 쥅 < 32.171431 < FMd2 / FMd1 < 41.904442 < FMd2 / EPD2 73.943451 < FMd1 / EPD1 < 42.59746FMd1 < FMd2 < FMd3만족471 < TTL / FMd2 < 21.474481 < TTL / FMd1 < 52.806491 < CA_Max / ImgH < 32.210505 < TTL / ImgH < 129.067510 <BFL2 / ImgH < 10.985520 < BFL3 / ImgH < 10.567531 < EPD1 < EPD2 <EPD3 < 10만족540 < Max_Distortion < 31.126558 < FOV3 <FOV2 < FOV1 <45만족 <h2 style=";text-align:left;direction:ltr"> <h2 style=";text-align:left;direction:ltr">

[0336] Referring to FIG. 4, the camera module includes the optical system (1000) disclosed above, and the optical system (1000) may include a reflective member (400) facing a subject or object, a lens unit (100) having a plurality of lens groups (LG1-LG4), and an image sensor (300). The camera module may include a plurality of driving members that drive each of the second to fourth lens groups (LG2-LG4). The reflective member (400) may be disposed on a path of light reflected on the subject. The reflective member (400) may be disposed closer to the subject than the lens unit (100). That is, the reflective member (400), the lens unit (100), and the image sensor (300) may be disposed in this order from the subject side toward the top. The reflective member (400) may change the path of light incident from the outside. The reflective member (400) may include a right-angle prism. When the reflective member (400) includes a right-angle prism, the reflective member (400) may reflect the path of light incident on the camera module (1000) at a 90-degree angle. The reflective member (400) may change the path of light reflected on the subject to a set direction. There is. For example, the reflective member (400) can reflect light incident on the reflective member (400) in the first direction (Y-axis direction) and change the path of the light to the optical axis direction (Z-axis direction) in which the plurality of lenses of the lens unit (100) are arranged.

[0337] When the above camera module includes the reflective member (400), it can be applied to a folded camera that can reduce the thickness of the camera module. The camera module is arranged parallel to the surface of the mobile terminal and can change light incident in a vertical second optical axis direction (OA2) into a first optical axis direction (OA1) that is parallel to the surface of the mobile terminal. Accordingly, the camera module (1000) including the lens unit (100) can have a low height in the direction perpendicular to the surface of the mobile terminal, and thus can have a thinner thickness within the mobile terminal, and thus the thickness of the device can also be thinner.

[0338] The driving member connected to the above reflective member (400) may include at least one actuator. The reflective member (400) can be moved using the driving force of the actuator, and the reflective member (400) can be tilt-controlled along a first axis or a second axis. Specifically, the reflective member (400) can be tilt-controlled with the second direction (Z-axis direction) as the rotation axis, and the reflective member (400) can be tilt-controlled with the third direction (OA1, Z-axis direction) as the rotation axis. Accordingly, the camera module can compensate for shaking.

[0339] It includes a sensing unit (not shown) that detects the shaking of the camera module, and the sensing unit can detect rotation and position changes applied to the camera module. The sensing unit may include at least one of a sensor that detects a change in angular velocity, for example, a gyro sensor, and an acceleration sensor that detects a change in acceleration.

[0340] The above camera module can control the movement of the reflective member (400) by a control signal. Specifically, when shaking occurs in the camera module, information about the shaking, such as the degree of rotation and position change of the sensors, can be detected, and compensation for the shaking can be performed. Accordingly, the camera module according to the embodiment can operate in wide mode, middle mode, and tele mode by the driving members, and when photographing a subject, shaking due to rotation and shaking due to position change can be effectively compensated. Accordingly, the camera module can have improved optical characteristics.

[0341]

[0342] FIG. 14 is a drawing illustrating a camera module according to an embodiment applied to a mobile terminal. Referring to FIG. 14, the mobile terminal (1) may include the camera module (10) disclosed in the embodiment on the rear side. As another example, the mobile terminal (1) may include the camera module disclosed in the embodiment on the front side. The camera module (10) may include an image capturing function. In addition, the camera module (10) may include at least one of an auto focus function, a zoom function, and an OIS function.

[0343] The camera module (10) can process still images or video frames obtained by the image sensor (300) in a shooting mode or a video call mode. The processed image frames can be displayed on a display unit (not shown) of the mobile terminal (1) and stored in a memory (not shown). In addition, although not shown in the drawing, the camera module may be further arranged on the front of the mobile terminal (1). For example, the camera module (10) may include a first camera module (10A) and a second camera module (10B). At this time, at least one of the first camera module (10A) and the second camera module (10B) may include the optical system (1000) described above. Accordingly, the camera module (10) may have a slim structure and may capture a subject at various magnifications.

[0344] The mobile terminal (1) may further include an auto-focus device (31). The auto-focus device (31) may include an auto-focus function using a laser. The auto-focus device (31) may be mainly used in conditions where the auto-focus function using the image of the camera module (10) is degraded, for example, at a close range of 10 m or less or in a dark environment. The auto-focus device (31) may include a light-emitting unit including a vertical cavity surface-emitting laser (VCSEL) semiconductor element, and a light-receiving unit that converts light energy into electrical energy, such as a photodiode.

[0345] 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 emit light in the visible light wavelength band. For example, the flash module (33) may emit white light or light of a color similar to white. However, the embodiment is not limited thereto, and the flash module (33) may emit light of various colors. The flash module (33) may be operated by the camera operation of the mobile terminal or by the user's control.

[0346]

[0347] FIG. 15 is an example of a plan view of a vehicle to which a camera module or optical system according to an embodiment of the invention is applied. Referring to FIG. 15, a vehicle camera system according to an embodiment of the invention includes an image generating unit (11), a first information generating unit (12), a second information generating unit (21, 22, 23, 24), and a control unit (14). The image generating unit (11) may include at least one camera module (20) disposed in the vehicle, and may capture images of the front of the vehicle and / or the driver to generate a front image or an interior image of the vehicle. The image generating unit (11) may capture images of the surroundings of the vehicle in one or more directions as well as the front of the vehicle using the camera module (20), to generate an image of the surroundings of the vehicle. Here, the front image and the surrounding images may be digital images, and may include color images, black and white images, infrared images, etc. In addition, the front image and the surrounding images may include still images and moving images. The image generation unit (11) provides the driver image, the front image, and the surrounding image to the control unit (14). Next, the first information generation unit (12) may include at least one radar and / or camera placed in the vehicle, and detects the front of the vehicle to generate first detection information. Specifically, the first information generation unit (12) is placed in the vehicle, and detects the position and speed of vehicles located in front of the vehicle, the presence and position of pedestrians, etc. to generate the first detection information.

[0348] By using the first detection information generated by the first information generating unit (12), the distance between the own vehicle and the vehicle in front can be controlled to be maintained at a constant level, and the stability of vehicle operation can be improved in specific preset cases, such as when the driver wants to change the driving lane of the own vehicle or when backing up and parking. The first information generating unit (12) provides the first detection information to the control unit (14). The second information generating unit (21, 22, 23, 24) detects each side of the own vehicle and generates second detection information based on the front image generated by the image generating unit (11) and the first detection information generated by the first information generating unit (12). Specifically, the second information generating unit (21, 22, 23, 24) may include at least one radar and / or camera disposed in the own vehicle, and may detect the position and speed of vehicles located on the side of the own vehicle or capture images. Here, the second information generation units (21, 22, 23, 24) can be placed at the front two corners, side mirrors, and rear center and rear two corners of the vehicle, respectively.

[0349] At least one information generating unit of these vehicle camera systems may include the optical system and the camera module having the same as described in the above-described embodiments, and may provide or process information acquired through the front, rear, each side, or corner area of ​​the vehicle to a user to enable autonomous driving or to protect the vehicle and objects from surrounding safety. The optical system of the camera module according to the embodiment of the invention may be installed in multiple units in a vehicle to enhance safety regulations, autonomous driving functions, and convenience. In addition, the optical system of the camera module is applied in a vehicle as a component for control such as a lane keeping assistance system (LKAS), a lane departure warning system (LDWS), and a driver monitoring system (DMS). These vehicle camera modules can implement stable optical performance even with changes in ambient temperature and provide modules with competitive prices, thereby ensuring the reliability of vehicle components.

[0350]

[0351] The features, structures, effects, etc. described in the embodiments above are included in at least one embodiment of the present invention, and are not necessarily limited to just one embodiment. Furthermore, the features, structures, effects, etc. illustrated in each embodiment can be combined or modified and implemented in other embodiments by a person having ordinary skill in the art to which the embodiments pertain. Therefore, the contents related to such combinations and modifications should be interpreted as being included in the scope of the present invention. Although the embodiments have been described above, these are merely examples and do not limit the present invention. Those having ordinary skill in the art to which the present invention pertains will appreciate that various modifications and applications not illustrated above are possible without departing from the essential characteristics of the embodiments. For example, each component specifically shown in the embodiments can be modified and implemented. In addition, differences related to such modifications and applications should be interpreted as being included in the scope of the present invention defined in the appended claims.

Claims

1. A first lens group adjacent to the object and having negative (-) refractive power; A second lens group arranged on the sensor side of the first lens group; A third lens group arranged on the sensor side of the second lens group; and A fourth lens group is disposed on the sensor side of the third lens group and includes a fourth lens group having positive (+) refractive power. The lenses of the first to fourth lens groups are aligned along the optical axis, At least two of the first to fourth lens groups move along the optical axis depending on the operating mode, The number of lenses in the first lens group is greater than the number of lenses in the second and third lens groups, The optical axis distance between the fourth lens group and the image sensor is variable, The total number of lenses in the first to fourth lens groups is nL, The number of lens groups to be moved among the first to fourth lens groups is nMLG, Mathematical formula: 2 < nL / nMLG < 3 Camera module that satisfies .

2. In paragraph 1, The above first lens group includes first to third lenses, The above second lens has a biconvex shape, A camera module wherein the third lens has a concave shape on both sides.

3. In paragraph 2, The second lens group includes the fourth and fifth lenses, A camera module wherein the fourth lens has a convex shape on both sides.

4. In paragraph 3, The third lens group includes the sixth and seventh lenses, A camera module wherein the sixth lens has a convex meniscus shape facing the image sensor.

5. In paragraph 4, The above seventh lens is a camera module having a concave shape on both sides.

6. In any one of paragraphs 1 to 5, The above second lens group has positive (+) refractive power, A camera module wherein the third lens group has negative (-) refractive power.

7. In any one of paragraphs 1 to 5, A camera module, wherein each of the second to fourth lens groups moves along the optical axis.

8. In any one of paragraphs 1 to 5, A camera module wherein the number of lenses in the second lens group and the third lens group is the same.

9. In paragraph 8, The number of lenses in the above 4th lens group is 1. A camera module in which the difference in absolute values ​​of the radii of curvature of the object-side surface and the sensor-side surface of the lenses of the first to fourth lens groups is such that the lens of the fourth lens group has the largest value.

10. In paragraph 8, A camera module in which the effective length of the lens of the fourth lens group is the maximum among the effective lengths of the lenses of the first to fourth lens groups.

11. In any one of paragraphs 1 to 5, A camera module in which the absolute values ​​of the focal lengths of the lenses of the first to fourth lens groups are the largest for the first lens.

Images