Optical system and camera module

Abstract

An optical system disclosed in an embodiment of the invention may include first to third lens groups arranged along an optical axis from an object toward a sensor side and each including at least one lens, wherein: the first lens group and the third lens group have negative power; the second lens group has positive power; the position of the first lens group is fixed; each of the second and third lens groups is movable along the optical axis according to an operation mode; a first lens closest to the object among the lenses of the first lens group has negative power; and the absolute value of the effective focal length of the third lens group is greater than the product of the absolute values of effective focal lengths of the first and second lens groups.

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] An optical system according to an embodiment of the invention comprises first to third lens groups arranged along an optical axis from an object toward a sensor side, each including at least one lens, wherein the first lens group and the third lens group have negative power, the second lens group has positive power, the position of the first lens group is fixed, and each of the second and third lens groups is movable along the optical axis according to an operation mode, a first lens closest to the object among the lenses of the first lens group has negative power, and an absolute value of an effective focal length of the third lens group may be greater than a product of the absolute values ​​of the effective focal lengths of the first and second lens groups.

[0008] According to an embodiment of the invention, among the lenses of the first to third lens groups, the maximum center thickness is CT_Max, the minimum center thickness is CT_Min, and the mathematical equation: 2 < CT_Max / CT_Min < 7 can be satisfied.

[0009] According to an embodiment of the invention, the maximum effective length among the object-side surfaces and the sensor-side surfaces of the lenses of the first to third lens groups is CA_Max, and the minimum effective length is CA_Min, and the mathematical formula: 1< CA_Max / CA_Min <3 can be satisfied.

[0010] According to an embodiment of the invention, the optical axis distance of the first lens group is TD1, the optical axis distance of the second lens group is TD2, and the mathematical formula: 1 < TD1 / TD2 < 1.8 can be satisfied.

[0011] According to an embodiment of the invention, depending on the operation mode, the maximum center spacing of adjacent lenses among the lenses of the first to third lens groups is Md_CG_Max, and the minimum center spacing is Md_CG_Min, and the mathematical formula: 2 < Md_CG_Max / Md_CG_Min < 8 can be satisfied.

[0012] According to an embodiment of the invention, the third lens group includes a last lens closest to the image sensor, and the last lens may have a biconvex shape on the optical axis.

[0013] According to an embodiment of the invention, the first lens group includes a first lens closest to the object, and the first lens may have a meniscus shape convex toward the object.

[0014] According to an embodiment of the invention, the optical axis distance between the last lens closest to the image sensor in the third lens group and the image sensor varies depending on the operating mode, and the operating mode of the optical system may include a wide mode, a middle mode, and a tele mode.

[0015] According to an embodiment of the invention, in the wide mode, the optical axis distance between the last lens and the image sensor is BFL1, and in the tele mode, the optical axis distance between the last lens and the image sensor is BFL3, and the mathematical expression: 1 < BFL3 / BFL1 < 3 can be satisfied.

[0016] According to an embodiment of the invention, in the middle mode, the optical axis distance between the last lens and the image sensor is BFL2, and half of the diagonal length of the effective area of ​​the image sensor is ImgH, and the mathematical expression: 2 < BFL2 / ImgH < 6 can be satisfied.

[0017] According to an embodiment of the invention, the number of lenses in the first and third lens groups is greater than the number of lenses in the second lens group, and the absolute value of the focal length of the first lens group may be greater than the focal length of the second lens group.

[0018] According to an embodiment of the invention, the effective focal length of the wide mode of the optical system is FMd1, the focal length of the first lens is F1, and the mathematical expression: 1 < │F1 / FMd1│ < 2 can be satisfied.

[0019] An optical system according to an embodiment of the invention comprises: a first lens group having first to third lenses; a second lens group having fourth and fifth lenses; A third lens group having sixth to eighth lenses, wherein the first to eighth lenses of the first lens group, the second lens group, and the third lens group are arranged in the optical axis direction from the object toward the sensor, the first lens has negative refractive power and has a convex shape on the object side, the third lens has negative refractive power and has a concave shape on the sensor side, the fourth lens has positive refractive power and has a biconvex shape, the eighth lens has negative refractive power and has a biconvex shape, the second lens group and the third lens group are moved in the optical axis direction, and an optical axis distance between the eighth lens and the image sensor varies depending on an operation mode, and the refractive index of the first lens is Nd1 and can satisfy the mathematical expression: 1.6 < Nd1.

[0020] According to an embodiment of the invention, the first and third lens groups may have negative refractive power, the second and fourth lenses may have positive refractive power, and the fourth lens and the eighth lens may have refractive indices of less than 1.6.

[0021] According to an embodiment of the invention, the effective length of the largest lens surface among the first to eighth lenses is CA_Max, and half of the diagonal length of the image sensor is ImgH, and the mathematical formula: 1 < CA_Max / ImgH < 3 can be satisfied.

[0022] A camera module according to an embodiment of the invention comprises an image sensor; an optical system; and a driving member for moving at least one of a plurality of lens groups of the optical system in the direction of an optical axis, wherein the optical system includes the optical system disclosed above, and the driving member can move the positions of each of the second and third lens groups of the optical system in the direction of the optical axis.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] FIG. 1 is a configuration diagram of an optical system and a camera module having the same according to an embodiment of the invention.

[0027] Fig. 2 is an example of a change in the first mode of the optical system of Fig. 1.

[0028] Figure 3 is an example of a change in the third mode in the optical system of Figures 1 and 2.

[0029] Fig. 4 is a configuration having a reflective mirror in the optical system of Fig. 1.

[0030] Figure 5 is a table of lens data of an optical system according to an embodiment of the invention.

[0031] Fig. 6 is a table showing aspherical coefficients of lenses of an optical system according to an embodiment of the invention.

[0032] FIG. 7 is a graph showing relative illumination according to positions in wide, middle, and tele modes according to an embodiment of the invention.

[0033] FIG. 8 is a graph of the diffraction MTF in the optical system of the first mode (Wide Mode) according to an embodiment of the invention.

[0034] FIG. 9 is a graph of the diffraction MTF in the optical system of the second mode (Middle Mode) according to an embodiment of the invention.

[0035] FIG. 10 is a graph of the diffraction MTF in the optical system of the third mode (Tele Mode) according to an embodiment of the invention.

[0036] Fig. 11 is a graph showing aberration characteristics in an optical system of the first mode according to an embodiment of the invention.

[0037] Fig. 12 is a graph showing aberration characteristics in an optical system of a second mode according to an embodiment of the invention.

[0038] Fig. 13 is a graph showing aberration characteristics in an optical system of a third mode according to an embodiment of the invention.

[0039] FIG. 14 is a graph showing the CRA (Chief ray angle) according to wide, middle, and tele modes in a camera module according to an embodiment of the invention.

[0040] FIG. 15 is a drawing showing a camera module according to an embodiment of the invention applied to a mobile terminal.

[0041] FIG. 16 is a drawing showing a camera module according to an embodiment of the invention applied to a mobile body.

[0042] 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.

[0043] 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.

[0044] 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.

[0045] In the specification, the convexity of the lens surface may mean that the lens surface in an area corresponding to the optical axis has a convex shape based on the optical axis, and the concaveness of the lens surface may mean that the lens surface in an area corresponding to the optical axis has a concave shape. In addition, the "object-side surface" may mean the surface of the lens facing the object side 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.

[0046]

[0047] FIG. 1 is a configuration diagram of a first mode of a camera module or optical system according to an embodiment of the invention, FIG. 2 is an example of a change from the first mode of the optical system of FIG. 1 to the second mode, FIG. 3 is an example of a change from the optical system of FIGS. 1 and 2 to the third mode, FIG. 4 is a configuration having a reflective mirror 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, FIG. 6 is a table showing aspherical coefficients of lenses of an optical system according to an embodiment of the invention, FIG. 7 is a graph showing relative illuminance according to positions of Wide, Middle, and Tele modes in a camera module according to an embodiment of the invention, FIG. 8 is a graph for diffraction MTF in an optical system of a first mode (Wide Mode) according to an embodiment of the invention, FIG. 8 is a graph for diffraction MTF in an optical system of a second mode (Middle mode) according to an embodiment of the invention, and FIG. 10 is a graph for diffraction MTF in an optical system of an embodiment of the invention. This is a graph for diffraction MTF in an optical system of the third mode (Tele mode), FIG. 11 is a graph showing aberration characteristics in an optical system of the first mode according to an embodiment of the invention, FIG. 12 is a graph showing aberration characteristics in an optical system of the second mode according to an embodiment of the invention, and FIG. 13 is a graph showing aberration characteristics in an optical system of the third mode according to an embodiment of the invention.

[0048] Referring to FIGS. 1 to 6, an optical system (1000) according to an embodiment may include a plurality of lens groups (G1, G2, G3). In detail, the plurality of lens groups (G1, G2, G3) may have at least two lens groups that are movable in the direction of the optical axis (OA) and at least one lens group that is fixed in position. The plurality of lens groups (G1, G2, G3) may include a lens group fixed on the object side and a plurality of movable lens groups that are movable on the sensor side.

[0049] The above-described plurality of moving lens groups may include an object-side lens group and a sensor-side lens group. The optical system (1000) may include a first lens group (G1), a second lens group (G2), and a third lens group (G3) sequentially arranged along the optical axis (OA) from the object side toward the sensor. The lens group fixed on the object side may be defined as the first lens group (G1), the object-side moving lens group may be defined as the second lens group (G2), and the sensor-side moving lens group may be defined as the third lens group (G3). The second lens group (G2) may be arranged between the first lens group (G1) and the third lens group (G3).

[0050] The first lens group (G1) refracts incident light toward the second lens group (G2), and the second lens group (G2) moves along the optical axis (OA) to change the zoom magnification (focal length), and the third lens group (G3) moves along the optical axis (OA) to adjust the focus position on the upper surface of the image sensor (300).

[0051] The optical system (1000) may include an image sensor (300) arranged on the sensor side of the third lens group (G3). The first lens group (G1) may include a lens closest to the object side, and the third lens group (G3) may include a lens closest to the image sensor (300). Each of the first to third lens groups (G1, G2, G3) may have positive (+) or negative (-) refractive power. For example, a lens group having positive refractive power may be smaller than a lens group having negative refractive power.

[0052]

[0053] The first lens group (G1) may have a refractive power opposite to that of the second lens group (G2). For example, the first lens group (G1) may have a negative (-) refractive power, and the second lens group (G2) may have a positive (+) refractive power. The second lens group (G2) may have a refractive power opposite to that of the third lens group (G3). For example, the second lens group (G2) may have a positive (+) refractive power, and the third lens group (G3) may have a negative (-) refractive power.

[0054] The absolute value of the focal length of the first lens group (G1) may be greater than the absolute value of the focal length of the second lens group (G2). Accordingly, the first lens group (G1) may disperse incident light. The focal length of the second lens group (G2) may be smaller than the absolute value of the focal length of the third lens group (G3). The absolute value of the focal length of the third lens group (G3) may be greater than the absolute value of the focal length of the first lens group (G1). Among the absolute values ​​of the focal lengths of the first to third lens groups (G1, G2, G3), the absolute value of the focal length of the third lens group (G3) may be the largest. The power of the first and third lens groups (G1, G3) may have negative power, and the power of the second lens (G2) may have positive power. The power is the reciprocal of the focal length value.

[0055] Since the first and second lens groups (G1, G2) have opposite refractive powers, aberrations can be corrected, and since the second and third lens groups (G2, G3) have opposite refractive powers, aberrations can be corrected. The absolute value of the focal length of each of the first to third lens groups (G1, G2, G3) can decrease in the order of the third lens group (G3), the first lens group (G1), and the second lens group (G2).

[0056]

[0057] The number of lenses of the first lens group (G1) may be greater than the number of lenses of the second lens group (G2). The number of lenses of the second lens group (G2) may be equal to or less than the number of lenses of the third lens group (G3). The number of lenses of the first lens group (G1) may include at least three lenses for adjusting the amount of incident light, refractive power, and chromatic aberration. The third lens group (G3) may include at least two or three lenses.

[0058] The number of lenses in each of the first to third lens groups (G1, G2, G3) may be two or more. At least one of the first and third lens groups (G1, G3) may have three or more lenses. As another example, the optical system may further include at least one lens whose position is fixed between the third lens group (G3) and the image sensor (300). Accordingly, the optical system (1000) may include seven or more and ten or fewer lenses.

[0059] Since the first lens group (G1) is fixed in position and the second lens group (G2) and the third lens group (G3) are movable in the direction of the optical axis (OA), the optical system (1000) can provide various magnifications by moving the lens groups.

[0060] Hereinafter, the first to third lens groups (G1, G2, G3) will be described in more detail. The first lens group (G1) may have at least two lenses having refractive powers of opposite signs. For example, the first lens group (G1) may include three lenses. The first lens group (G1) may have a smaller number of lenses having negative refractive power than lenses having positive refractive power.

[0061]

[0062] The first lens group (G1) includes a plurality of lenses, and the plurality of lenses may have a set interval on the optical axis (OA). In detail, the center interval between the plurality of lenses (101, 102, 103) included in the first lens group (G1) may be a fixed interval according to an operation mode to be described later. For example, the center interval between adjacent lenses (101, 102, 103) may not change depending on the operation mode and may have a constant interval. Here, the center interval between the lenses may mean the optical axis interval between adjacent lenses.

[0063] The second lens group (G2) may include a plurality of lenses, and may include lenses (104, 105) having refractive powers of the same sign. The plurality of lenses (104, 105) included in the second lens group (G2) may have a set interval. In detail, the center interval between adjacent lenses (104, 105) may be a fixed interval depending on the operation mode described below.

[0064]

[0065] The third lens group (G3) may include a plurality of lenses, and may include two or more lenses having refractive powers of opposite signs. The number of lenses included in the third lens group (G3) having negative refractive power may be smaller than the number of lenses having positive refractive power. The number of lenses included in the third lens group (G3) may be at least one more than the number of lenses included in the second lens group (G2). The number of lenses included in the third lens group (G3) may be equal to the number of lenses included in the first lens group (G1). For example, the third lens group (G3) may include three lenses.

[0066] The plurality of lenses (106, 107, 108) included in the third lens group (G3) may have a set spacing. In detail, the center spacing between the plurality of lenses (106, 107, 108) included in the third lens group (G3) may be constant without changing even when the operation mode described later changes. For example, the center spacing between adjacent lenses (106, 107, 108) may be constant without changing depending on the operation mode. The last lens included in the third lens group (G3) has a set spacing with respect to the image sensor (300) or / and the optical filter (500), and the spacing may vary depending on the operation mode.

[0067]

[0068] The optical system (1000) may include first to eighth lenses (101-108). The first lens group (G1) may include the first to third lenses (101, 102, 103), and the second lens group (G2) may include the fourth and fifth lenses (104, 105). In addition, the third lens group (G3) may include the sixth to eighth lenses (106, 107, 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).

[0069]

[0070] The first lens group (G1) may have at least one lens therein whose effective length in the first direction (X) perpendicular to the optical axis and whose effective length in the second direction (Y) are different from each other. The lenses of the first lens group (G1) having different effective lengths in the first and second directions (X, Y) may be non-circular lenses, and for example, the effective length in the second direction (Y) may be smaller than the effective length in the first direction (X). One or two or more of the first to third lenses (101, 102, 103) may have an effective length in the second direction (Y) of the object-side surface thereof that is smaller than the effective length in the first direction (X).

[0071] The second lens group (G2) may have at least one internal lens having an effective length in the first direction (X) perpendicular to the optical axis and an effective length in the second direction (Y) that are different from each other. The lenses of the second lens group (G2) having different effective lengths in the first and second directions (X, Y) may be non-circular lenses, and for example, the effective length in the second direction (Y) may be smaller than the effective length in the first direction (X). One or both of the fourth and fifth lenses (104, 105) may have an effective length in the second direction (Y) of the object-side surface that is smaller than the effective length in the first direction (X).

[0072] The third lens group (G3) may have at least one internal lens having a length in the first direction (X) perpendicular to the optical axis and a length in the second direction (Y) that are different from each other. The lenses of the first lens group (G1) having different effective lengths in the first and second directions (X, Y) may be non-circular lenses, and for example, the effective length in the second direction (Y) may be smaller than the effective length in the first direction (X).

[0073] In detail, among the lenses in the lens unit (100), the first lens (101) having the largest effective length may have an effective length in the first direction (X) that is greater than an effective length in the second direction (Y). The second lens (102) may have an effective length in the first direction (X) that is greater than an effective length in the second direction (Y). The fourth lens (104) may have an effective length in the first direction (X) that is greater than an effective length in the second direction (Y).

[0074] 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.

[0075]

[0076] Each of the plurality of lenses (100) may include an effective area and an ineffective area. The effective area may be an area of ​​an effective diameter, and may be an area through which light incident on each of the first to eighth lenses (101-108) passes. The effective area may be an area in 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 in which the light is not incident. In other words, the ineffective area may be an area unrelated to the optical characteristics. In addition, the ineffective area may be an area fixed to a barrel (not shown) that accommodates the lens.

[0077] The image sensor (300) can detect light. The image sensor (300) can detect light that has sequentially passed through the plurality of lenses (100), for example, the first to eighth lenses (101-108). The image sensor (300) can include a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor).

[0078]

[0079] The optical system (1000) may further include an optical filter (500). The optical filter (500) may be positioned between the plurality of lenses (100) and the image sensor (300). The optical filter (500) may be positioned between the image sensor (300) and the third lens group (G3). For example, the optical filter (500) may be positioned between the eighth lens (108) and the image sensor (300).

[0080] The optical filter (500) may include at least one of an infrared filter and a cover glass. The optical filter (500) may allow light of a set wavelength band to pass through and filter light of a different wavelength band. When the optical filter (500) includes an infrared filter, it may block radiant heat emitted from external light from being transmitted to the image sensor (300). The optical filter (500) may transmit visible light and reflect infrared light.

[0081]

[0082] The optical system (1000) may include an aperture (not shown). The aperture may control the amount of light incident on the optical system (1000). For example, the aperture may be arranged on the periphery between the third lens (103) and the fourth lens (104). The aperture may be arranged on the periphery of the sensor-side surface of the third lens (103). As another example, the aperture may be arranged on the periphery of the object-side surface of the fourth lens (104). The aperture may be arranged between two lenses selected from the first to eighth lenses (101-108). Alternatively, at least one lens from the first to eighth lenses (101-108) may function as an aperture. For example, the outer surface of the object-side surface or the sensor-side surface of one lens selected from the first to eighth lenses (101-108) may function as an aperture for controlling the amount of light. For example, at least one lens surface of the sensor-side surface of the third lens (103) or the object-side surface of the fourth lens (104) may function as an aperture.

[0083]

[0084] The object-side surface and the sensor-side surface of the first to eighth lenses (101-108) may be aspherical. The first to eighth lenses (101-108) may be made of plastic or glass. All of the first to eighth lenses (101-108) may be made of plastic, or at least one may be made of glass. The number of lenses made of plastic may be greater than the number of lenses made of glass. As another example, when the first to eighth lenses (101-108) are a mixture of plastic lenses and glass lenses, at least one of the lenses may be made of glass.

[0085] The optical system (1000) may further include an optical path changing member (400) as shown in FIG. 4. The optical path changing member (400) may reflect light incident from the outside to change the path of the light from a second path (OA2) to a first path (OA1). The optical path changing member (400) may include a reflector or a prism. For example, the optical path changing member (400) may include a right-angled prism. When the optical path changing member (400) includes a right-angled prism, the optical path changing member (400) may reflect the second path (OA2) of the incident light at an angle of 90 degrees to change the first path (OA1) of the light. The first path (OA1) may be in the direction of the optical axis of the optical system. The optical path changing member (400) may be arranged closer to the object side than the plurality of lenses. That is, when the optical system (1000) includes the optical path changing member (400), the optical path changing member (300), the first lens (101) to the eighth lens (108), the filter (500), and the image sensor (300) may be arranged in this order from the object side toward the sensor.

[0086] The optical path changing member (400) can change the path of light incident from the outside to a set direction. For example, the optical path changing member (400) can change the second path (OA2) of light incident on the optical path changing member (400) in a second direction (Y) to a first path (OA1) in a third direction (Z), which is the arrangement direction of the plurality of lenses. When the optical system (1000) includes the optical path changing member (400), the optical system can be applied to a folded camera, thereby reducing the thickness of the camera. In detail, when the optical system (1000) includes the optical path changing member (400), light incident in a direction (Y) perpendicular to the surface of a device to which the optical system (1000) is applied can be changed to a direction (Z) parallel to the surface of the device. Accordingly, the optical system (1000) including a plurality of lenses can have a thinner thickness within the device, so that the height of the device can be reduced.

[0087]

[0088] When the optical system (1000) does not include the optical path changing member, the plurality of lenses may be arranged to extend in a direction (Y) perpendicular to the surface of the device. Accordingly, the optical system (1000) including the plurality of lenses has a high height in a direction perpendicular to the surface of the device (first direction), which may make it difficult to form the optical system (1000) and the device including it thin. However, when the optical system (1000) includes the optical path changing member (400), the plurality of lenses may be arranged to extend in a direction (Z) parallel to the surface of the device. That is, the optical system (1000) is arranged such that the optical axis (OA) is parallel to the surface of the device and may be applied to a folded camera. Accordingly, the optical system (1000) including the plurality of lenses (100) may have a low height in a direction perpendicular to the surface of the device. Accordingly, the camera including the optical system (1000) can have a thin thickness within the device, and the thickness of the device can also be reduced.

[0089] As another example, the optical path changing member may be disposed between two lenses among the plurality of lenses (100), or further disposed between the last lens adjacent to the image sensor (300) and the image sensor (300). As another example, the optical path changing member may be provided in multiple pieces. In detail, a plurality of the optical path changing members may be disposed between the object and the image sensor (300). For example, the plurality of optical path changing members may include a first optical path changing member disposed closer to the object side than the plurality of lenses, and a second optical path changing member disposed between the last lens and the image sensor (300). Accordingly, the optical system (1000) may have various shapes and heights depending on the camera to which it is applied, and may have improved optical performance.

[0090]

[0091] Referring to FIGS. 1 to 3, 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 to 108) is CT1 to CT8, the edge thickness is ET1 to ET8, the Abbe number is Vd1 to Vd8, the refractive index is Nd1 to Nd8, the average of the effective lengths of each lens is CA1 to CA8, and the focal length of each lens may be defined as F1 to F8.

[0092] The first lens (101) may have a negative refractive power on the optical axis (OA). The first lens (101) may include a plastic or glass material, and may be, for example, a plastic material. The first lens (101) may include a first surface (S1) on the object side and a second surface (S2) on the sensor side. The first surface (S1) may have a convex shape on the optical axis (OA), and the second surface (S2) may have a concave shape on the optical axis (OA). That is, the first lens (101) may have a meniscus shape that is convex toward the object on the optical axis (OA). Alternatively, the first lens (101) may have a concave shape on the optical axis on the first surface (S1), and a convex shape on the optical axis on the second surface (S2). At least one of the first surface (S1) and the second surface (S2) may be aspherical. For example, both the first surface (S1) and the second surface (S2) may be aspherical. As shown in Fig. 6, the aspherical coefficients of the first and second surfaces (S1, S2) may be represented from the 4th to the 20th order, and may represent the radius of curvature (Y) and the conic constant.

[0093]

[0094] The maximum effective length of the first lens (101) may be the largest among the lenses. That is, the effective length of the first surface (S1) of the first lens (101) in the second direction (Y) may be the largest among the lenses. The average of the effective lengths of the first and second surfaces (S1, S2) of the first lens (101) in the second direction (Y) may be larger than the average of the effective lengths of the object-side surfaces and the sensor-side surfaces of the second to eighth lenses (102-108). 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 a critical point from the optical axis to the end of the effective area.

[0095]

[0096] 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 on the optical axis (OA), and the sensor-side fourth surface (S4) may have a convex shape on the optical axis (OA). The second lens (102) may have a convex shape on both sides on the optical axis (OA). Alternatively, the third surface (S3) may have a convex shape on the optical axis (OA), and the fourth surface (S4) may have a concave shape. 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 concave shape, and the fourth surface (S4) may have a concave shape. At least one of the third surface (S3) and the fourth surface (S4) of the second lens (102) may be aspherical. For example, both the third surface (S3) and the fourth surface (S4) may be aspherical. The aspherical coefficient and the conic constant of the third and fourth surfaces (S3, S4) may be represented by L2S3 and L2S4 in FIG. 6.

[0097]

[0098] The third lens (103) may have a refractive power of the same sign as the refractive power 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.

[0099] The object-side fifth surface (S5) of the third lens (103) may have a concave shape on the optical axis (OA), and the sensor-side sixth surface (S6) may have a concave shape on the optical axis (OA). The third lens (103) may have concave shapes on both sides. Alternatively, the fifth surface (S5) may have a convex shape on the optical axis (OA), and the sixth surface (S6) may have a convex shape. Alternatively, the fifth surface (S5) may have a concave shape on the optical axis (OA), and the sixth surface (S6) may have a convex shape. At least one of the fifth surface (S5) and the sixth surface (S6) of the third lens (103) may be aspherical. For example, both the fifth surface (S5) and the sixth surface (S6) may be aspherical. The aspherical coefficient and conic constant of the fifth and sixth surfaces (S5, S6) can be expressed as L3S5 and L3S6 in Fig. 6.

[0100]

[0101] The second lens (102) and the third lens (103) can compensate for chromatic aberration occurring in the first lens (101). The refractive indexes of the first and second lenses (101, 102) may be greater than 1.6. The radius of curvature of the first surface (S1) of the first lens (101) may be the largest among the absolute values ​​of the radii of curvature of the first to sixth surfaces (S1-S6) of the first to third lenses (101-103). Accordingly, the first lens group (G1) can control the dispersion of light provided to the second lens group (G2) and reduce the lens size of the second lens group (G2). The center spacing between the first and second lens groups (G1, G2) can be adjusted according to the operating mode by the radius of curvature of the sixth surface (S6) of the third lens (103).

[0102]

[0103] The fourth lens (104) may have a positive (+) refractive power in the optical axis (OA). The fourth lens (104) may include a plastic or glass material, for example, a glass material, and may have a refractive index of less than 1.6. The fourth lens (104) may include a seventh surface (S7) defined as an object-side surface and an eighth surface (S8) defined as a sensor-side surface. The seventh surface (S7) may have a convex shape in the optical axis (OA), and the eighth surface (S8) may have a convex shape in the optical axis (OA). That is, the fourth lens (104) may have a convex shape on both sides in the optical axis (OA). Alternatively, the seventh surface (S7) may be convex in the optical axis (OA), and the eighth surface (S8) may be concave in the optical axis (OA). That is, the fourth lens (104) may have a convex meniscus shape toward the object from the optical axis (OA).

[0104] The central thickness (CT4) of the fourth lens (104) may be the largest among the lenses. The central thickness (CT3) of the third lens (103) may be the thinnest among the lenses. The central thickness (CT4) of the fourth lens (104) may be thicker than the edge thickness (ET4), and may be, for example, more than twice the edge thickness. Accordingly, this may affect the aberration improvement of the optical system.

[0105] At least one of the seventh surface (S7) and the eighth surface (S8) of the fourth lens (104) may be aspherical. For example, both the seventh surface (S7) and the eighth surface (S8) may be aspherical. The aspherical coefficient and the conic constant of the seventh and eighth surfaces (S7, S8) may be represented as L4S7 and L4S8 in FIG. 6.

[0106]

[0107] The fifth lens (105) may have positive (+) or negative (-) refractive power in the optical axis (OA). The fifth lens (105) may have negative refractive power opposite to that of the fourth lens (104) in the optical axis (OA). The fifth lens (105) may include a plastic or glass material, and may be, for example, a plastic material. The fifth lens (105) may include a ninth surface (S9) defined as an object-side surface and a tenth surface (S10) defined as a sensor-side surface. The ninth surface (S9) may have a concave shape in the optical axis (OA), and the tenth surface (S10) may have a convex shape in the optical axis (OA). That is, the fifth lens (105) may have a meniscus shape that is convex toward the sensor in the optical axis (OA). At least one of the ninth surface (S9) and the tenth surface (S10) may be aspherical. For example, both the ninth surface (S9) and the tenth surface (S10) may be aspherical. The aspherical coefficient and the conic constant of the ninth and tenth surfaces (S9, S10) may be represented as L5S9 and L5S10 in FIG. 6.

[0108] As another example, the ninth surface (S9) of the fifth lens (105) may have a convex shape in the optical axis (OA), and the tenth surface (S10) may have a convex shape in the optical axis (OA). That is, the fifth lens (105) may have a convex shape on both sides in the optical axis (OA). Alternatively, the ninth surface (S9) may have a concave shape in the optical axis (OA), and the tenth surface (S10) may have a concave shape in the optical axis (OA). Alternatively, the ninth surface (S9) may have a convex shape in the optical axis (OA), and the tenth surface (S10) may have a concave shape in the optical axis (OA).

[0109]

[0110] The fourth lens (104) has a convex shape on both sides, and the object-side surface of the fifth lens (105) has a concave shape, so that the gap between the fourth lens (104) and the fifth lens (105) can be reduced. The Abbe number (Ad4) of the fourth lens (104) can be the largest among the Abbe numbers of the first to seventh lenses (101-107). The difference in the Abbe numbers between the fourth lens (104) and the fifth lens (105) can be greater than 20. Accordingly, the second lens group (G2) can minimize the change in chromatic aberration caused by the position changing according to the change in the operation mode.

[0111]

[0112] The sixth lens (106) may have positive (+) or negative (-) refractive power in the optical axis (OA), for example, may have negative 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) defined as an object-side surface and a twelfth surface (S12) defined as a sensor-side surface. The eleventh surface (S11) may have a convex shape 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 concave shape in the optical axis (OA), and the twelfth surface (S12) may have a convex 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). 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).

[0113] At least one of the eleventh surface (S11) and the twelfth surface (S12) of the sixth lens (106) may be aspherical. For example, both the eleventh surface (S11) and the twelfth surface (S12) may be aspherical. The aspherical coefficient and the conic constant of the eleventh and twelfth surfaces (S11, S12) may be represented by L6S11 and L6S12 of FIG. 6. The center thickness (CT6) of the sixth lens (106) may be thinner than the edge thickness (ET6). Accordingly, the difference between the center thickness (CT6) and the edge thickness (ET6) of the sixth lens (106) may refract incident light in the direction of the optical axis.

[0114]

[0115] The seventh lens (107) may have positive (+) or negative (-) refractive power on the optical axis (OA), and may have positive 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.

[0116] The seventh lens (107) may include a thirteenth surface (S13) defined as an object-side surface and a fourteenth surface (S14) defined as a sensor-side surface. The thirteenth surface (S13) may have a convex shape in the optical axis (OA), and the fourteenth surface (S14) may have a concave shape in the optical axis (OA). That is, the seventh lens (107) may have a meniscus shape convex toward the object in the optical axis (OA). As another example, the thirteenth surface (S13) may have a concave shape in the optical axis (OA), and the fourteenth surface (S14) may have a concave shape in the optical axis (OA). Alternatively, the thirteenth surface (S13) may have a concave shape in the optical axis (OA), and the fourteenth surface (S14) may have a convex shape in the optical axis (OA). In contrast, the 13th surface (S13) may have a convex shape in the optical axis (OA), and the 14th surface (S14) may have a convex shape in the optical axis (OA).

[0117] At least one of the 13th surface (S13) and the 14th surface (S12) of the 7th lens (107) may be aspherical. For example, both the 13th surface (S13) and the 14th surface (S14) may be aspherical. The aspherical coefficient and the conic constant of the 13th and 14th surfaces (S13, S14) may be represented by L7S13 and L7S14 in FIG. 6. The 13th surface (S13) and the 14th surface (S14) may be provided without a critical point from the optical axis to the end of the effective area.

[0118] The sixth lens (106) and seventh lens (107) have refractive powers of opposite signs, and can control chromatic aberration when the Abbe number difference is set to 10 or less. Accordingly, the third lens group (G3) can minimize chromatic aberration changes caused by positions that change according to mode changes and perform an achromatic function.

[0119]

[0120] The eighth lens (108) may have a negative (-) refractive power on the optical axis (OA). The eighth lens (108) may include a plastic or glass material, and may be, for example, a plastic material. The eighth lens (108) may include a fifteenth surface (S15) defined as an object-side surface and a sixteenth surface (S16) defined as a sensor-side surface. The fifteenth surface (S15) may have a convex shape on the optical axis (OA), and the sixteenth surface (S16) may have a convex shape on the optical axis (OA). That is, the eighth lens (108) may have a convex shape on both sides on the optical axis (OA). Alternatively, the eighth lens (108) may have a concave shape on the optical axis (OA), and the sixteenth surface (S16) may have a convex shape on the optical axis (OA). In contrast, the eighth lens (108) may have a meniscus shape convex toward the object from the optical axis (OA).

[0121]

[0122] At least one of the fifteenth surface (S15) and the sixteenth surface (S16) of the eighth lens (108) may be an aspherical surface. For example, both the fifteenth surface (S15) and the sixteenth surface (S16) may be aspherical surfaces. The aspherical coefficient and the conic constant of the fifteenth and sixteenth surfaces (S15, S16) may be represented by L8S15 and L8S16 of FIG. 6. At least one of the fifteenth surface (S15) and the sixteenth surface (S16) may have a critical point from the optical axis to the end of the effective area. For example, the fifteenth surface (S15) may have a critical point between the optical axis and the end of the effective area. The critical point is a point where the trend of the Sag value changes. That is, the inflection 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 above Sag value is the optical axis distance between a straight line perpendicular to the center of each lens surface and the lens surface. The Sag value has a positive value at a position located on the sensor side relative to the center of each lens surface, and a negative value at a position located on the object side relative to the center of each lens surface.

[0123] The center thickness (CT8) of the above-mentioned eighth lens (108) may be thicker than the edge thickness (ET8). Accordingly, the difference between the center thickness and the edge thickness of the above-mentioned eighth lens (108) and the inflection point of the fifteenth surface (S15) may refract the incident light to the periphery of the image sensor (300).

[0124]

[0125] The above-mentioned eighth lens (108) may be closest to the image sensor (300) among the plurality of lenses (101-108). The above-mentioned third lens group (G3) may be moved in the optical axis direction, and the optical axis distance (BFL) between the eighth lens (108) and the image sensor (300) may vary depending on the operating mode. Here, the BFL (Back focal length) is the optical axis distance from the center of the sensor-side 16th surface (S16) of the eighth lens (108) to the image sensor (300).

[0126]

[0127] The third lens group (G3) may play a role in controlling the chief ray angle (CRA). Specifically, 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 third lens group (G3) may correct the chief ray angle of light incident on the image sensor (300) according to each operation mode.

[0128]

[0129] A camera module according to an embodiment of the invention may include the optical system (1000) described above. The camera module may move the second and third lens groups (G2, G3) among the plurality of lens groups (G1, G2, G3) included in the optical system (1000) in the direction of the optical axis (OA). The camera module may include a driving member (not shown) connected to the optical system (1000). The driving member is arranged on the outer side of the second lens group (G2) and the outer side of each of the third lens groups (G3), and may move each in the direction of the optical axis (OA) according to an operation mode.

[0130] 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.

[0131] The driving member can move (M1, M2) each of the second and third lens groups (G2, G3) 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 (G2) and the third lens group (G3), and can move the second lens group (G2) or the third lens group (G3) according to the operation mode. The initial mode may be any one of the first, second, and third modes, for example, the second mode or the middle mode. For example, in the first mode, each of the second lens group (G2) and the third lens group (G3) may be positioned at a position defined as a first position (Position 1). In the second mode, each of the second lens group (G2) and the third lens group (G3) may be positioned at a second position (Position 2) that is closer to the object than the first position. In the third mode, each of the second lens group (G2) and the third lens group (G3) may be positioned at a third position (Position 3) that is closer to the sensor side than the first position. The first position may be an area between the second and third positions.

[0132]

[0133] The first position at which the second lens group (G2) is positioned in the first mode may be an area between the second and third positions at which the second lens group (G2) is positioned in the second and third modes. The first position at which the third lens group (G3) is positioned in the first mode may be an area between the second and third positions at which the third lens group (G3) is positioned in the second and third modes.

[0134] Depending on the operation mode, at least one of the second lens group (G2) and the third lens group (G3) can move along the optical axis, and the first lens group (G1) can be arranged at a fixed position. Depending on the operation mode, the second lens group (G2) can move (M1), and the first lens group (G1) can be arranged at a fixed position. Depending on the operation mode, the third lens group (G3) can move (M2), and the first lens group (G1) can be arranged at a fixed position.

[0135] In each of the first position, the second position, and the third position according to the operation mode, the first to third lens groups (G1, G2, G3) may have a set interval from the adjacent lens groups. Accordingly, the optical system (1000) may have a constant TTL (Total track length or Total top length) 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 of the lens groups.

[0136]

[0137] The effective length (CA1) of the first lens (101) is the largest among the lenses, and the effective diameter (CA5) of the fifth lens (105) is the smallest among the lenses. The effective length (CA1) of the first lens (101) may be 5 mm or more. The effective length (CA5) of the fifth lens (105) may be less than 6 mm.

[0138] In the absolute value of the focal length, the focal length (F6) of the sixth lens (106) may be the largest among the lenses, and in the difference (absolute value) of the focal length between adjacent two lenses, the difference between the seventh and eighth lenses (107, 108) may be the largest, and the difference between the second and third lenses (102, 103) may be the smallest.

[0139] The center thickness (CT4) of the fourth lens (104) may be the thickest among the lenses, and the center thickness (CT3) of the third lens (103) may be the thinnest among the lenses. The absolute values ​​of the radii of curvature of the first to sixth surfaces (S1-S6) of the first, second, and third lenses (101, 102, and 103) may be set to 5 mm or more, so as not to significantly change the angle of refraction of the incident light. The light incident through the first to third lenses (101-103) may be guided to the fourth lens (104) of the second lens group (G2).

[0140] The sum of the central thicknesses (CT3, CT4) of the third and fourth lenses (103, 104) of the second lens group (G2) may be greater than the sum of the central thicknesses (CT1, CT2, CT3) of the first, second and third lenses (101, 102, 103). The sum of the central thicknesses (CT3, CT4) of the third and fourth lenses (103, 104) of the second lens group (G2) may be less than the sum of the central thicknesses (CT6, CT7, CT8) of the sixth, seventh and eighth lenses (106, 107, 108). Accordingly, the second lens group (G2) can guide the light incident on the first lens group (G1) to the effective area of ​​the third lens group (G3).

[0141]

[0142] The optical axis spacing (CG3) between the first and second lens groups (G1, G2) and the optical axis spacing (CG5) between the second and third lens groups (G2, G3) may each be at least 0.2 mm or more depending on the change in magnification of the operating modes. Specifically, the optical axis spacing (CG3) between the first and second lens groups (G1, G2) may be moved by 0.2 mm or more, for example, in the range of 0.2 mm to 15 mm, and the optical axis spacing (CG5) between the second and third lens groups (G2, G3) may be moved by 1 mm or more, for example, in the range of 1 mm to 20 mm. In addition, the center spacing (BFL) between the eighth lens (108) and the optical filter (500) may be moved by 1 mm or more, for example, in the range of 1 mm to 15 mm.

[0143] The relationship between CG3, CG5, and BFL in modes 1, 2, and 3 is as follows.

[0144] Mode 1: BFL < CG5 < CG3

[0145] Mode 2: CG3 < CG5 < BFL

[0146] Mode 3: CG3 < BFL < CG5

[0147] Depending on the operating mode, the F number of the optical system (1000) provides a brightness of 2.0 or more, and the F number may be in the range of 2 to 7. The aperture may be located between the first lens group (G1) and the second lens group (G2).

[0148]

[0149] An optical system (1000) according to an embodiment can satisfy at least one or two or more of the mathematical equations described below. Accordingly, the optical system (1000) according to an embodiment can effectively correct aberrations that change according to changes in the operation mode. In addition, the optical system (1000) according to an embodiment can effectively provide an autofocus (AF) function for a subject at various magnifications, and can have a slim and compact structure.

[0150] 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 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, and effective diameter values ​​are mm. In addition, the effective length includes a circular or non-circular shape of the lens surface, and can be defined as the major axis effective length or the maximum diameter when the lens has a partially circular shape.

[0151] [Mathematical Formula 1] nL_G2 > 1 (nL is an integer greater than or equal to 2)

[0152] In mathematical expression 1, nL_G2 refers to the number of lenses included in the second lens group (G2). Here, the relationship nL_G1 > nL_G2, nL_G3 > nL_G2 may be present. nL_G1 refers to the number of lenses included in the first lens group (G1), and nL_G3 refers to the number of lenses included in the third lens group (G3).

[0153] [Mathematical Formula 2] 0.7 < CA41 / CA11 < 1.2

[0154] In mathematical expression 2, CA41 is the effective length of the seventh surface (S7) of the fourth lens (104), and CA11 is the maximum effective length of the first surface (S1) of the first lens (101). When mathematical expression 2 is satisfied, a high entrance pupil size (EPD: Entrance Pupil Diameter) compared to the optical system can be provided. Preferably, mathematical expression 2 can satisfy 0.7 < CA41 / CA11 < 1.

[0155] [Mathematical Formula 2-1] 1 < CA1 / CA2 < 2

[0156] CA1 is the average of the effective lengths of the object-side surface and the sensor-side surface of the first lens (101), and CA2 is the average of the effective lengths of the object-side surface and the sensor-side surface of the second lens (102). Preferably, 1 < CA1 / CA2 < 1.5 can be satisfied. When mathematical expression 2-1 is satisfied, factors affecting the aberration of the optical system can be adjusted.

[0157] [Mathematical Formula 3] 1 < CT1 / CT3 < 3

[0158] When mathematical expression 3 satisfies the central thickness of the first and third lenses (101, 103), the aberration characteristics in the optical system (1000) can be improved. Preferably, 1.5 < CT1 / CT3 < 2.5 can be satisfied.

[0159] [Mathematical Formula 4] 0 < CT1 / CT4 < 1

[0160] In mathematical expression 4, when the center thicknesses (CT1, CT4) of the first and fourth lenses (101, 104) are satisfied, the optical system (1000) can improve aberration characteristics. Preferably, 0.2 < CT1 / CT4 < 0.5 can be satisfied. Since the center thickness (CT4) of the fourth lens (104) is the thickest among the lenses and has a convex shape on both sides, the fourth lens (104) can improve the light incident efficiency of the light incident through the first lens group (G1) and refract the light into the effective area of ​​the fifth lens (105) having the smallest effective length.

[0161] [Equation 4-1] 2 < CT4 / CT3 < 6

[0162] When the central thicknesses (CT3, CT4) of the third and fourth lenses (103, 104) in mathematical expression 4-1 are satisfied, the optical system (1000) can improve aberration characteristics. Preferably, 4 < CT3 / CT4 < 6 can be satisfied.

[0163] [Equation 5] 2 < ET3 / CT3 < 4

[0164] In mathematical expression 5, ET3 represents the thickness (mm) in the optical axis direction at the end of the effective area of ​​the third lens (103). When the optical system (1000) according to the embodiment satisfies mathematical expression 5, the optical system (1000) can improve the distortion characteristics of light passing through the first lens group (G1). Preferably, 2 < ET3 / CT3 < 3 can be satisfied.

[0165] [Mathematical Formula 5-1] 1 < CT4 / ET4 < 3

[0166] When the center thickness (CT4) and edge thickness (ET4) of the fourth lens (104) in mathematical expression 5-1 are satisfied, the optical system (1000) can improve aberration characteristics. Preferably, 1.5 < CT4 / ET4 < 2.6 can be satisfied.

[0167]

[0168] If the center thickness of the ith lens is CTi and the edge thickness of the ith lens is ETi, the ratio of CTi / ETi may be largest when i is 4 and smallest when i is 3. That is, the lens with the largest difference between the center thickness and the edge thickness may be arranged as the object-side lens of the second lens group (G2), and the lens with the smallest difference may be arranged as the sensor-side lens of the first lens group (G1).

[0169]

[0170] [Equation 6] FG1 < 0

[0171] In mathematical expression 6, FG1 is the effective focal length (EFL) of the first lens group (G1), and can have a value less than 0. FG1 is the 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 (G1), can be improved.

[0172] The effective focal length of the second lens group (G2) is FG2, the effective focal length of the third lens is FG3, and the following mathematical equation can be satisfied.

[0173] [Equation 6-1]: FG2 <│FG1│

[0174] [Equation 6-2]: FG2*7 <│FG3│ (* is multiplication)

[0175] [Equation 6-3]: │FG1│*FLG2 <│FG3│

[0176] In this way, by adjusting the focal length of each lens group, the angle of refraction of light passing through the lenses can be adjusted.

[0177]

[0178] [Equation 7] CRA < 20

[0179] In mathematical expression 7, CRA (Chief Ray Angle) is the chief ray incident angle, and in the optical system, the incident angle of the chief ray may be less than 20 degrees at most, and may be 15 degrees or less, depending on the first, second, and third modes. 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. Here, in the case of the first mode (Wide), the chief ray incident angle may be greater than the chief ray incident angle in the case of the second mode at a field of 1.0. In the case of the third mode (Tele), the chief ray incident angle may be 11 degrees or less at a field of 1.0, and the chief ray incident angle of the second mode may be smaller than the chief ray incident angle of the first mode. When mathematical expression 6 is satisfied, the peripheral light ratio can be secured. As shown in Fig. 14, in a graph showing the CRA of the optical system in wide mode, middle mode, and tele mode, the difference in CRA according to the operating mode can be 5 degrees or less from the center (0.0F) to the edge (1.0Field) of the image sensor.

[0180] [Equation 8] 3.5 < (TTL / DG1)

[0181] In mathematical expression 8, DG1 is the optical axis distance of the first lens group (G1), for example, the optical axis distance from the center of the object-side surface of the first lens (101) to the center of the sensor-side surface of the third lens (103). For example, DG1 means the distance (mm) 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) according to the embodiment satisfies mathematical expression 8, the optical system (1000) has a relatively small TTL and can secure a peripheral light ratio.

[0182] The following mathematical formulas may be further included.

[0183] [Equation 8-1] (TTL / DG1) < (TTL / DG2)

[0184] [Equation 8-2] DG3 < DG2

[0185] Here, DG2 is the optical axis distance of the second lens group (G2), and is the distance from the center of the object-side surface of the fourth lens (104) to the center of the sensor-side surface of the fifth lens (105). DG3 is the optical axis distance of the third lens group (G3), and is the distance from the center of the object-side surface of the sixth lens (106) to the center of the sensor-side surface of the eighth lens (108).

[0186] [Equation 9] 2 < TTL / EPD3 < 12

[0187] 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) according to the embodiment 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 4 or less in Tele mode. Preferably, 5 < TTL / EPD3 < 9 can be satisfied.

[0188] [Equation 9-1] 5 < TTL / EPD1 < 13

[0189] [Equation 9-2] 5 < TTL / EPD2 < 10

[0190] [Equation 9-3] (TTL / EPD3) < (TTL / EPD2) < (TTL / EPD1)

[0191] In mathematical expressions 9-1 to 9-3, 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.

[0192] [Equation 10] 2 < CT_Max / CT_Min < 7

[0193] 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 < CT_Max / CT_Min < 6 can be satisfied.

[0194] [Mathematical Formula 11] 1 < CA_Max / CA_Min < 3

[0195] In mathematical expression 11, CA_Max is the largest effective diameter 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 < CA_Max / CA_Min < 1.5 can be satisfied.

[0196]

[0197] [Equation 12] 0.1 < ΣCG_Wide / TTL < 0.8

[0198] In mathematical expression 12, ΣCG_Wide is the sum of the center spacings between adjacent lenses in the first mode. When the optical system satisfies mathematical expression 12, the center spacing between the first and second lens groups and the center spacing between the second and third lens groups can be set according to the Wide mode. The center spacing between the first and second lens groups may be the center spacing (CG3) between the third and fourth lenses (103, 104) and varies depending on the operation mode. The center spacing between the second and third lens groups may be the center spacing (CG5) between the fifth and sixth lenses (105, 106) and varies depending on the operation mode. Preferably, 0.3 < ΣCG_Wide / TTL < 0.6 can be satisfied.

[0199] [Equation 12-1] 0.05 < ΣCG_Mid / TTL < 0.4

[0200] [Equation 12-2] 0.3 < ΣCG_Tele / TTL < 0.7

[0201] In mathematical expressions 12-1 and 12-2, ΣCG_Mid is the sum of the center spacings between adjacent lenses in the second mode, and ΣCG_Tele is the sum of the center spacings between adjacent lenses in the third mode. When the optical system satisfies mathematical expressions 12-1 and 12-2, the center spacing between the first and second lens groups and the center spacing between the second and third lens groups can be set according to the middle mode and the tele mode. Preferably, the condition of ΣCG_Mid < ΣCG_Tele < ΣCG_Wide can be satisfied.

[0202] When the optical system (1000) according to the embodiment satisfies at least one or two of mathematical expressions 1 to 12, the optical system (1000) may have a slim structure. In addition, the optical system (1000) may have improved assemblability and a mechanically stable shape.

[0203]

[0204] [Mathematical Formula 13] 0.5 < DG1 / DG2 < 2

[0205] In mathematical expression 13, DG1 is the optical axis distance of the first lens group (G1), and DG2 is the optical axis distance of the second lens group (G2). By setting the optical axis distances of the first and second lens groups (G1, G2) in mathematical expression 13, TTL can be adjusted. Preferably, 0.8 < DG1 / DG2 < 1 can be satisfied.

[0206] [Mathematical Formula 14] 0.5 < DG2 / DG3 < 1

[0207] In mathematical expression 14, DG2 is the optical axis distance of the second lens group (G2), and DG3 is the optical axis distance of the third lens group (G3). Preferably, 0.5 < DG2 / DG3 < 0.8 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.

[0208] [Equation 15] 1 < CG1 / CG2 < 5

[0209] In mathematical expression 15, CG1 is the center spacing between the first and second lenses (101, 102), and CG2 is the center spacing between the second lens (102) and the third lens (103). When the optical system (1000) satisfies mathematical expression 15, the optical system (1000) has a relatively small TTL and can have improved optical characteristics by controlling stray light incident on the first lens group (G1). Preferably, 2 < CG1 / CG2 < 4 can be satisfied.

[0210] [Equation 16] 2 < TTL / (DG2+DG3) < 5

[0211] Mathematical expression 16 sets the sum of the optical axis distances of the TTL and the second and third lens groups (G2, G3), 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.

[0212]

[0213] [Equation 17] 20 < |Vd4 - Vd5| < 70

[0214] In mathematical expression 17, Vd4 means the Abbe number of the fourth lens (104), and Vd5 means 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 the chromatic aberration characteristics. Preferably, Vd5 < Vd4 is satisfied, and 50 < Vd4 and 50 <Vd8를 만족할 수 있다.

[0215] [Equation 18] 15 < |Vd8 - Vd7| < 60

[0216] In mathematical expression 18, Vd8 represents the Abbe number of the eighth lens, and Vd7 represents the Abbe number of the seventh lens. When the absolute value of the difference in Abbe numbers between the seventh and eighth lenses satisfies mathematical expression 18, the optical system (1000) can improve chromatic aberration characteristics. Preferably, Vd7 < Vd8 can be satisfied.

[0217] [Equation 19] 1.6 < Nd1

[0218] In mathematical expression 19, Nd1 represents the refractive index at the d-line of the first lens (101). When the optical system (1000) according to the embodiment satisfies mathematical expression 19, it can disperse incident light and secure the effective area of ​​the lens placed after the first lens (101). Preferably, 1.7 < Nd1 can be satisfied.

[0219] [Equation 19-1] 1.6 < Nd1 < Nd2

[0220] [Equation 19-2] 1.6 < Nd2 < Nd7

[0221] Nd2 is the refractive index of the second lens, and Nd7 is the refractive index of the seventh lens. The refractive indices (Nd4, Nd8) of the fourth and eighth lenses (104, 108) may be less than 1.6, and the refractive index of at least one of the fourth and eighth lenses (104, 108) may be the lowest among the lenses. Among the lenses, the number of lenses having a refractive index greater than 1.60 is 4 or more, for example, 5.

[0222] [Equation 20] 1 < L1R1 / L3R2 < 3.5

[0223] 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) according to the embodiment satisfies mathematical expression 20, the optical system (1000) can control stray light incident on the first lens group (G1). Preferably, 1.5 < L1R1 / L3R2 < 2.5 can be satisfied. Since the third lens (103) has a sensor-side surface having a concave shape on the optical axis, the effective diameter of the fourth lens (104) can be suppressed from increasing.

[0224] [Mathematical Formula 21] 3 < L1R1 / L4R1 < 10

[0225] 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. Preferably, 5 < L1R1 / L4R1 < 9 can be satisfied.

[0226] [Mathematical Formula 22] 1 < L3R2 / L4R1 < 6

[0227] In mathematical expression 22, L3R2 denotes the radius of curvature of the sensor-side sixth surface (S6) of the third lens (103), 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 22, the optical system (1000) can have good optical performance at the periphery of the field of view (FOV) when operating at various magnifications of at least three modes. Preferably, 2 < L3R2 / L4R1 < 5 can be satisfied. The fourth lens (104) is the first lens of the second lens group (G2), has a convex shape on both sides on the optical axis, and can have positive power. Accordingly, the gap between the convex sensor-side surface of the fourth lens (104) and the concave object-side surface of the fifth lens (105) can be closely packed.

[0228] [Equation 23] 1 < L1R1 / |L8R2| < 3

[0229] 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 have good optical performance in the center and periphery of the field of view (FOV). Preferably, 1.3 < L1R1 / |L8R2| < 2.5 can be satisfied.

[0230]

[0231] [Equation 24] 0 < Md12_mG2 / TTL < 0.5

[0232] In mathematical expression 24, Md12_mG2 refers to the difference in the center spacing after the movement of the second lens group (G2) when changing from the second mode to the first mode or from the first mode to the second mode. Specifically, the Md12_mG2 represents the movement distance of the second lens group (G2) in the first and second modes, and refers to the difference value between the optical axis spacing between the first and second lens groups (G1, G2) in the first mode and the optical axis spacing between the first and second lens groups (G1, G2) in the second mode. When the optical system (1000) according to the embodiment satisfies mathematical expression 24, the optical system (1000) can minimize the movement distance of the second lens group (G2) when the magnification is changed, and thus the optical system (1000) can have a slim structure. In addition, since the movement distance can be minimized when controlling the position of the second lens group (G2), it can have improved power consumption characteristics. Preferably, 0.1 < Md12_mG2 / TTL < 0.3 can be satisfied.

[0233] [Equation 25] 0 < Md23_mG2 / TTL < 0.5

[0234] In mathematical expression 25, Md23_mG2 refers to the difference in the center spacing after movement of the second lens group (G2) when operating from the second mode to the third mode, or from the third mode to the second mode. Specifically, Md23_mG2 refers to the difference value between the optical axis spacing between the first and second lens groups (G1, G2) in the second mode and the optical axis spacing between the first and second lens groups (G1, G2) in the third mode. The maximum movement distance of the second lens group (G2) may be greater than the maximum movement distance of the third lens group (G3). When the optical system (1000) according to the embodiment satisfies mathematical expression 25, the optical system (1000) can minimize the movement distance of the second lens group (G2) when the magnification is changed, and thus the optical system (1000) can have a slim structure. In addition, since the movement distance can be minimized when controlling the position of the second lens group (G2), it can have improved power consumption characteristics. Preferably, 0 < Md23_mG2 / TTL < 0.1 can be satisfied. In addition, the condition of Md23_mG2 < Md12_mG2 can be satisfied.

[0235]

[0236] [Equation 26] 1 < Md12_mG2 / DG2 < 2.5

[0237] Mathematical expression 26 can set the movement distance of the second lens group (G2) and the optical axis distance of the second lens group (G2). When the optical system (1000) satisfies Mathematical expression 26, the optical system (1000) can minimize the movement distance of the second lens group (G2) 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 (G2), so that it can have improved power consumption characteristics. Preferably, 1.5 < Md12_mG2 / DG2 < 2 can be satisfied.

[0238] [Mathematical Formula 27] 0 < Md23_mG3 / DG3 < 0.5

[0239] In mathematical expression 27, Md23_mG3 refers to the difference in the center spacing after the movement of the third lens group (G3) 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 third lens group (G3) 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 third lens group (G3), so that it can have improved power consumption characteristics. Preferably, 0.1 < Md23_mG3 / DG3 < 0.3 can be satisfied.

[0240]

[0241] [Equation 28] 1 < (CT1 / ET1) / (CT3 / ET3) < 5

[0242] In mathematical expression 28, CT1 and ET1 are the center thickness and edge thickness of the first lens (101), and CT3 and ET3 are the center thickness and edge thickness of the third lens (103). If the value obtained by dividing the center thickness and edge thickness of the first and third lenses (101, 103) by the above ratio satisfies mathematical expression 28, chromatic aberration can be improved and incident light can be controlled. Preferably, 1 < (CT1 / ET1) / (CT3 / ET3) < 2 can be satisfied.

[0243] [Equation 29] 0 < (CT1 / ET1) / (CT7 / ET7) < 1

[0244] In mathematical expression 29, CT7 and ET7 are the center thickness and edge thickness of the seventh lens (107). If the values ​​obtained by dividing the center thickness and edge thickness of the first and seventh lenses (101, 107) by the above ratio satisfy mathematical expression 29, chromatic aberration can be improved and incident light can be controlled. Preferably, 0.2 < (CT1 / ET1) / (CT7 / ET7) < 0.7 can be satisfied.

[0245]

[0246] [Mathematical Formula 30] 1 < Md1(DG12 / DG23) < 5

[0247] 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, 1 < Md1(DG12 / DG23) < 3 may be satisfied.

[0248] [Equation 31] 0 < Md3(DG12 / DG23) < 0.7

[0249] In mathematical expression 31, Md3(DG12 / DG23) represents the ratio between the center spacing (DG12) between the first and second lens groups in the third 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 31, the optical system (1000) can have improved optical characteristics at the second magnification. In detail, the optical system (1000) can have improved aberration characteristics at the second magnification and improve the optical performance of the peripheral part of the field of view (FOV). Preferably, 0 < Md3(DG12 / DG23) < 0.1 can be satisfied.

[0250]

[0251] [Equation 32] 0.5 < TD2 / TTL < 1

[0252] In mathematical expression 32, TD2 is the optical axis distance from the center of the object-side surface of the first lens to the center of the sensor-side surface of the eighth lens in the second mode. When the optical system (1000) according to the embodiment satisfies mathematical expression 32, the optical system (1000) can have improved optical characteristics in the middle mode, which is the second mode. In detail, the optical system (1000) can have improved aberration characteristics in the middle mode and improve optical performance in the peripheral part of the field of view (FOV).

[0253] [Equation 33] 1 < TD1 / TD2 < 1.8

[0254] In mathematical expression 33, TD1 is the optical axis distance from the center of the object-side surface of the first lens to the center of the sensor-side surface of the eighth lens in the first mode. When the optical system (1000) according to the embodiment satisfies mathematical expression 33, the optical system (1000) can have improved optical characteristics in the first and second modes and can reduce the influence on TTL. In detail, the optical system (1000) can have improved aberration characteristics in the first and second modes and can improve the optical performance of the peripheral part of the field of view (FOV). Preferably, 1 < TD1 / TD2 < 1.5 can be satisfied.

[0255] [Equation 33-1] 0.5 < TD1 / TTL < 1

[0256] The maximum optical axis distance of the lenses for each mode is TD1, and mathematical expression 33-1 can set the relationship between TD1 and TTL.

[0257] [Equation 33-2] 1 < TD1 / TD3 < 1.5

[0258] In mathematical expression 33-2, TD3 is the optical axis distance from the center of the object-side surface of the first lens to the center of the sensor-side surface of the eighth lens in the third mode. The optical system (1000) can have improved optical characteristics in the first and third modes, and can reduce the influence on TTL.

[0259]

[0260] [Mathematical Formula 34] 20mm < TD2 < TD3 < TD1 < 40mm

[0261] Mathematical expression 34 is a diagram comparing the optical axis distances of lenses in the first, second, and third modes, and TD3 is the optical axis distance from the center of the object-side surface of the first lens to the center of the sensor-side surface of the eighth lens in the third mode. When the optical system (1000) according to the embodiment satisfies Mathematical expression 34, the optical system (1000) can have improved optical characteristics in the first, second, and third modes. In detail, the optical system (1000) can have improved aberration characteristics in the first, second, and third modes and improve optical performance in the peripheral portion of the field of view (FOV).

[0262] [Equation 35] 0.1 < BFL2 / TTL < 1

[0263] In mathematical expression 35, BFL2 (Back focal length 1) is the optical axis distance from the center of the sensor-side surface of the last lens or the eighth lens adjacent to the image sensor (300) to the upper surface of the image sensor in the second mode. When the optical system (1000) according to the embodiment satisfies mathematical expression 35, the optical system (1000) can adjust the focal position toward the upper surface of the image sensor (300) in the second mode. In detail, the optical system (1000) has improved optical characteristics in the second mode and can improve the optical performance of the periphery of the field of view (FOV). Preferably, 0.2 < BFL2 / TTL < 0.5 can be satisfied.

[0264] [Equation 36] 0.5 < BFL3 / BFL1 < 3

[0265] In mathematical expression 36, BFL3 is the optical axis distance from the center of the sensor-side surface of the last lens or the eighth lens to the upper surface of the image sensor in the third mode. When the optical system (1000) according to the embodiment satisfies mathematical expression 36, the optical system (1000) can adjust the focus position to the upper surface of the image sensor (300) in the first and third modes. In detail, the optical system (1000) has improved optical characteristics in the first and third modes and can improve the optical performance in the peripheral part of the field of view (FOV). Preferably, 1 < BFL3 / BFL1 < 1.5 can be satisfied.

[0266] [Equation 37] 3 < TD3 / BFL3 < 8

[0267] Mathematical expression 37 is a value comparing the optical axis distance (TD3) between the center of the object-side surface of the first lens and the center of the sensor-side surface of the last lens or the eighth lens in the third mode, and the optical axis distance (BFL3) from the center of the sensor-side surface of the eighth lens (108) to the image surface of the image sensor. When the optical system (1000) according to the embodiment satisfies Mathematical expression 37, the optical system (1000) can have improved optical characteristics in the third mode. In detail, the optical system (1000) can have improved aberration characteristics in the third mode and improve optical performance in the peripheral part of the field of view (FOV). Preferably, 5 < TD3 / BFL3 < 8 can be satisfied.

[0268]

[0269] [Equation 38] 2 < Md_CG_Max / Md_CG_Min < 8

[0270] In mathematical expression 38, Md_CG_Max refers to the maximum center spacing among the center spacings between the first to eighth lenses in the first, second, and third modes, and Md_CG_Min refers to the minimum center spacing among the center spacings between the first to eighth lenses in the first, second, and third modes. When the optical system satisfies mathematical expression 38, the TTL and the optical axis distance of the lenses can be adjusted according to each mode. Preferably, 5.5 < Md_CG_Max / Md_CG_Min < 7.6 can be satisfied.

[0271] [Mathematical Formula 39] 1mm < BFL_Min < 6mm

[0272] Mathematical expression 39 indicates that BFL_Min represents the minimum distance between the eighth lens and the image sensor during the operating mode. If the optical system satisfies Mathematical expression 39, the minimum distance between the last lens and the image sensor can be secured. Preferably, 3 mm < BFL_Min < 5.5 mm can be satisfied. BFL_Min is the BFL value in the first mode.

[0273] [Equation 40] 30 < Aver_Vd < 50

[0274] In mathematical expression 40, Aver_Ad 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 < 40 can be satisfied.

[0275] [Equation 41] 1.5 < Aver_Nd < 1.8

[0276] 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, 1.55 < Aver_Nd < 1.7 can be satisfied.

[0277] [Equation 41-1] 10 < ∑Ad / ∑Nd < 40

[0278] In mathematical expression 41-1, ²Ad represents the sum of the Abbe numbers of each of the plurality of lenses. ²Nd represents 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) may have improved aberration characteristics and resolution. Preferably, mathematical expression 41-1 may satisfy 17 < ∑Ad / ∑Nd < 25.

[0279]

[0280] [Equation 42] 2 < │ FG1 / FG2 │ < 4

[0281] In mathematical expression 42, FG1 represents the effective focal length (EFL) of the first lens group (G1), and FG2 represents the effective focal length of the second lens group (G2). FG2 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, TTL, can be reduced. Preferably, FG2 > 0 is satisfied. FG3 is the composite focal length of the sixth to eighth lenses, and FG3 < 0. Preferably, 1 < │ FG1 / FG2 │ < 2 can be satisfied.

[0282] [Mathematical Formula 43] 1 < FMd2 / FMd1 < 10

[0283] In mathematical expression 43, FMd1 is the effective focal length of the optical system in the first mode, and FMd2 is the effective focal length of the optical system in the second mode. Preferably, 1 < FMd2 / FMd1 < 3 can be satisfied. When the optical system satisfies mathematical expression 43, the effective focal length can be adjusted according to the first and second modes.

[0284] [Equation 43-1] 1 < FMd3 / FMd2 < 3

[0285] In Equation 43, FMd3 is the effective focal length of the optical system in the third mode. Preferably, 1 < FMd3 / FMd2 < 2 can be satisfied. When the optical system satisfies Equation 43-1, the effective focal length can be adjusted according to the second and third modes. In addition, FMd1 < FMd2 < FMd3 can be satisfied.

[0286]

[0287] Additionally, in the first mode, the effective focal length (Fmd1) of the optical system and the focal length of each lens can satisfy the following conditions.

[0288] Condition 1: 1 < │F1 / FMd1│ < 2

[0289] Condition 2: 0 < F2 / FMd1 < 1

[0290] Condition 3: 0 < │F3 / FMd1│ < 1

[0291] Condition 4: 1 < │F4 / FMd1│ < 2

[0292] Condition 5: 2 < │F5 / FMd1│ < 4

[0293] Condition 6: 1 < │F6 / FMd1│ < 3

[0294] Condition 7: 1 < F7 / FMd1 < 3

[0295] Condition 8: 3 < │F8 / FMd1│ < 5

[0296]

[0297] [Equation 44] 2 < FMd2 / EPD2 < 7

[0298] In mathematical expression 44, FMd2 is the effective focal length of the optical system in the second mode (Middle), and EPD2 means the size of the entrance pupil (EPD) 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 < 6 can be satisfied.

[0299] [Mathematical Formula 45] 1 < FMd1 / EPD1 < 3

[0300] 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.

[0301] [Mathematical Formula 46] FMd1 < FMd2 < FMd3

[0302] 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.

[0303]

[0304] [Mathematical Formula 47] 0 < TTL / FMd2 < 2

[0305] Mathematical expression 47 can adjust TTL by comparing the effective focal length in TTL and the second mode. Preferably, 1.5 < TTL / FMd2 < 2 can be satisfied.

[0306] [Mathematical Formula 48] 1 < TTL / FMd1 < 5

[0307] Mathematical expression 47 can adjust TTL by comparing the effective focal length in TTL and the first mode. Preferably, 2 < TTL / FMd1 < 4 can be satisfied.

[0308] [Equation 49] 1 < CA_Max / ImgH < 3

[0309] In mathematical expression 49, CA_Max refers to the size (CA) of the largest effective diameter among the lens surfaces of the plurality of lenses (100) included in the optical system (1000). ImgH refers to the distance from the 0 field, which is the center of the image surface of the image sensor (300) overlapping the optical axis (OA), to the 1.0 field 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 4 mm.

[0310] Here, the effective lengths (CA1 to CA8) of the first to eighth lenses (101 to 108) can satisfy the following conditions.

[0311] Condition 1: 1 < CA1 / (ImgH*2) < 1.5

[0312] Condition 2: 0.4 < CA2 / (ImgH*2) < 1

[0313] Among the effective lengths of the lenses (CA1-CA8), the lenses with lengths smaller than the maximum effective diagonal length of the image sensor are the 2nd, 3rd, 4th, 5th, 6th, and 7th lenses.

[0314] [Mathematical Formula 50] 5 < TTL / ImgH < 14

[0315] 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 < 12.

[0316] [Equation 51] 2 < BFL2 / ImgH < 6

[0317] When the optical system (1000) according to the embodiment satisfies mathematical expression 51, the BFL required for a small image sensor less than 1 inch can be secured. In addition, when the optical system (1000) satisfies mathematical expression 51, the optical system (1000) can operate at various magnifications while maintaining TTL, and can have excellent optical characteristics in the center and periphery of the field of view (FOV). Preferably, it can be in the range of 3 < BFL2 / ImgH < 5.

[0318] [Equation 52] 1 < BFL3 / ImgH < 4

[0319] When the optical system (1000) according to the embodiment satisfies mathematical expression 52, the BFL required for a small image sensor less than 1 inch can be secured. When the optical system (1000) satisfies mathematical expression 52, the optical system (1000) can operate at various magnifications while maintaining TTL, and can have excellent optical characteristics in the center and periphery of the field of view (FOV). Preferably, 1 < BFL3 / ImgH < 2 can be satisfied.

[0320] [Mathematical Formula 53] 1 < EPD1 < EPD2 < EPD3 < 7

[0321] In mathematical expression 53, EPD1, EPD2, and EPD3 represent the size of the entrance pupil of the optical system according to the first to third modes, and the brightness according to each mode can be adjusted.

[0322] [Equation 54] 0 < Max_Distortion < 3

[0323] In mathematical expression 54, distortion refers to the maximum value or maximum value of 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 54, the optical system (1000) can improve the distortion characteristics and set conditions for image processing. Preferably, Max_Distortion < 1.5 can be satisfied.

[0324] [Mathematical Formula 55] 8° < FOV3 <FOV2 < FOV1 < 45°

[0325] In mathematical expression 55, FOV1, FOV2, and FOV3 represent the diagonal angles of view of the optical system in the first, second, and third modes. FOV (Field of view) represents the diagonal angle of view (Degree) of the optical system (1000), and can provide an optical system of less than 45 degrees. In addition, the relationship between the angles of view (FOV1, FOV2, and FOV3) according to each mode and the optical axis spacing (BFL1, BFL2, and BLF3) between the last lens and the image sensor (300) can satisfy the following conditions.

[0326] Condition 1: 5 < FOV1 / BFL1 < 15

[0327] Condition 2: 1 < FOV2 / BFL2 < 2

[0328] Condition 3: 2 < FOV3 / BFL3 < 3

[0329]

[0330] [Equation 56]

[0331]

[0332] In mathematical expression 56, Z may represent Sag, which is the distance from any position on the aspherical surface to the vertex of the aspherical surface in the direction of the optical axis. In addition, Y may represent the distance from any 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.

[0333]

[0334] 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.

[0335] 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.

[0336]

[0337] Hereinafter, the optical system (1000) according to the embodiment and the first to third mode changes will be described in more detail. In the optical system (1000) according to the embodiment, the first lens group (G1) can be fixed, and the second lens group (G2) and the third lens group (G3) can move according to the operation mode. The first lens group (G1) can include three lenses, for example, the first to third lenses (101, 102, 103), and the second lens group (G2) can include two lenses, for example, the fourth and fifth lenses (104, 105). In addition, the third lens group (G3) can include three lenses, for example, the sixth to eighth lenses (106, 107, 108).

[0338] In the optical system (1000) according to the embodiment, the object-side surface (seventh surface (S7)) of the fourth lens (104) can function as an aperture, and the optical filter (500) described above can be placed between the fourth lens group (G4) and the image sensor (300).

[0339] FIG. 5 shows the radius of curvature of the first to eighth lenses (101-108) on the optical axis (OA), the center thickness (CT) of the lenses, the center spacing (CG) between adjacent components, for example, lenses, the refractive index at the d-line, the Abbe's Number, and the clear aperture (CA). In FIG. 5, CT / CG(W) is the center thickness of each lens and the center spacing between adjacent lenses in the wide mode, CT / CG(M) is the center thickness of each lens and the center spacing between adjacent lenses in the middle mode, and CT / CG(T) is the center thickness of each lens and the center spacing between adjacent lenses in the tele mode.

[0340]

[0341] The camera module according to the embodiment can obtain information about the subject at various magnifications. Specifically, the driving member can control the positions of the second lens group (G2) and the third lens group (G3), thereby allowing the camera module to operate at various magnifications. For example, referring to FIGS. 1, 8, and 11, the camera module including the optical system (1000) can operate in the first mode having the first magnification. In the first mode, each of the second lens group (G2) and the third lens group (G3) can be moved to a set position. Accordingly, each of the first to third lens groups (G3) can be arranged at a set interval. For example, the second lens group (G2) can be positioned in an area spaced apart from the first lens group (G1) at a first interval, and the third lens group (G3) can be positioned in an area spaced apart from the second lens group (G2) at a second interval. Here, the first and second intervals may refer to the intervals between the lens groups on the optical axis (OA), and may vary depending on the operating mode.

[0342] When the camera module operates in the first mode, the optical system (1000) may have a TTL value and a BFL1 value at the first position. In addition, the optical system (1000) may have an FMD1 defined as a first effective focal length (EFL) at the first position. In addition, in the first mode, the field of view (FOV) of the camera module may be less than about 40 degrees, and the F-number may be less than about 5.

[0343] When the camera module operates in the second mode, the optical system (1000) may have a TTL (Total Track Length) value and a BFL2 value at the second position. In addition, the optical system (1000) may have a FMD2 defined as a second effective focal length (EFL) at the second position. In addition, the field of view (FOV) of the camera module in the second mode may be less than about 25 degrees, and the F-number may be less than about 5.

[0344] When the camera module operates in the third mode, the optical system (1000) may have a TTL (Total Track Length) value and a BFL3 value at the third position. In addition, the optical system (1000) may have FMD3, which is defined as a third effective focal length (EFL), at the third position. In addition, in the third mode, the field of view (FOV) of the camera module may be less than about 20 degrees, and the F-number may be less than about 6.

[0345]

[0346] As shown in Fig. 7, the relative illumination (RI) in each mode can change depending on the height of the image sensor, and it can be seen that the relative illumination at the periphery or edge (1.0 Field) at the height of the image sensor (Field Height) is 55% or more.

[0347] The optical system (1000) can have excellent aberration characteristics as shown in FIGS. 8 and 11 in the first mode. Specifically, FIG. 8 is a graph of diffraction MTF characteristics of the optical system (1000) operating in the first mode (first magnification), and FIG. 11 is a graph of aberration characteristics. The diffraction MTF characteristic graph is measured in units of approximately 0.252 mm over a spatial frequency range of 0.000 mm to 2.2520 mm. In the diffraction MTF graph, T represents the MTF change in spatial frequency per millimeter of a tangential circle, and R represents the MTF change in spatial frequency per millimeter of a radial circle. Here, the MTF (Modulation Transfer Function) depends on the spatial frequency of cycles per millimeter.

[0348] In the second mode, it can have excellent aberration characteristics as in FIGS. 9 and 12. Specifically, FIG. 9 is a graph of the diffraction MTF characteristics of an optical system (1000) operating in the second mode (second magnification), and FIG. 12 is a graph of the aberration characteristics. In the third mode, it can have excellent aberration characteristics as in FIGS. 10 and 13. Specifically, FIG. 10 is a graph of the diffraction MTF characteristics of an optical system (1000) operating in the third mode (third magnification), and FIG. 13 is a graph of the aberration characteristics.

[0349] The graphs of Figs. 11 to 13 are graphs measuring spherical aberration (longitudinal spherical aberration), astigmatic field curves, and distortion from left to right. In Figs. 11 to 13, the X-axis may represent the focal length (mm) and the 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 the 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 the wavelength band of 546 nm. In the aberration diagrams of Figs. 11 to 13, the closer each curve is to the Y-axis, the better the aberration correction function can be interpreted.

[0350]

[0351] Table 1 and FIG. 3 are for the items of the mathematical formulas described above in the optical system (1000) of the embodiment, and are for the TTL (mm), BFL (Back focal length), effective focal length (F) (mm), ImgH (mm), effective diameter (CA) (mm), thickness (mm), TD (mm), which is the optical axis distance from the first surface (S1) to the fourteenth surface (S14), the focal lengths (F1, F2, F3, F4, F5, F6, F7, F8) of each of the first to seventh lenses, the sum of the refractive indices of each lens, the sum of the Abbe numbers of each lens, the sum of the center thicknesses of each lens (mm), the sum of the center spacings between adjacent lenses, the effective diameter, the diagonal angle of view (FOV) (Degree), the edge thickness (ET), the focal lengths of the first and second lens groups, the F number, etc.

[0352] Item Example Item Example F116.05ET11.57F2-7.11ET20.52F35.61ET31.43F4-13.20ET41.42F5-24.32ET52.46F6-12.79ET62.10F715.96ET72.31F846.47ET81.92FG1-16.191ΣCG_Wide21.352FG210.999ΣCG_Mid11.400FG3-2994.840ΣCG_Tele20.960ΣIndex12.869ImgH3.528ΣAbbe264.191TTL40.635ΣCT14.305

[0353] Table 2 shows the center spacing between the first and second lens groups according to the first to third modes, the center spacing between the second and third lens groups, the center spacing between the eighth lens and the optical filter (DG4), the effective focal length (EFL) according to each mode, the entrance pupil size (EPD) according to each mode, the optical axis distance (TD) of the lens according to each mode, the F number, angle of view, and BFL according to each mode.

[0354] Item 1 Mode 2 Mode 3 Mode DG12 (mm) 12.4 15 3.65 6 0.500 DG23 (mm) 5.3 2 34.1 29 16.846 EFL (FMd1 / FMd2 / FMd3) (mm) 11.4 00 21.7 00 32.000 EPD (EPD1 / EPD2 / EPD3) 4.2 34 4.61 45.357 TD (TD1 / TD2 / TD3) (mm) 40.6 35 40.63 540.635 F-number2 69 34.7 0 45.974 FOV (degrees) 36.8 5 7 19.7 113.111 BFL (BFL1 / BFL2 / BFL3) (mm) 4.97 9 14.93 15.370

[0355] Tables 3 and 4 show the results for the mathematical expressions 1 to 55 described above in the optical system (1000) of the embodiment. Referring to Table 3, it can be seen that the optical system (1000) satisfies at least one, two or more, or three or more of the mathematical expressions 1 to 55. In detail, it can be seen that the optical system (1000) according to the embodiment satisfies all of the mathematical expressions 1 to 55. Accordingly, the optical system (1000) can have good optical performance and excellent optical characteristics in the center and periphery of the field of view (FOV).

[0356] 수학식실시예1nL_G2 > 1만족20.7 < CA41 / CA11 < 1.20.84231 < CT1 / CT3 < 31.85140 < CT1 / CT4 < 10.33352 < ET3 / CT3 < 42.6386FG1 < 0-16.1917CRA < 20만족83.5 < (TTL / DG1) >8.79392 < TTL / EPD3 < 127.586102 < CT_Max / CT_Min < 75.552111 < CA_Max / CA_Min < 31.377120.1 < ΣCG_Wide / TTL < 0.80.525130.5 < DG1 / DG2 < 20.902140.5 < DG2 / DG3 < 10.627151 < CG1 / CG2 < 53.360162 < TTL / (DG2+DG3) < 53.0561720 < |Vd4 - Vd5| <7030.5321815 < |Vd8 - Vd7| < 6036.470191.6 < Nd11.639201 < L1R1 / L3R2 < 3.51.828213 < L1R1 / L4R1 < 107.868221 < L3R2 / L4R1 < 64.303231 < L1R1 / |L8R2| < 31.791240 < Md12_mG2 / TTL < 0.50.216250 < Md23_mG2 / TTL < 0.50.029261 < Mde12_mG2 / DG2 < 2.51.709270 < Md23_mG3 / DG3 < 0.50.146281 < (CT1 / ET1) / (CT3 / ET3) < 51.679290 < (CT1 / ET1) / (CT7 / ET7) < 10.526301 < Md1 (DG12 / DG23) < 52.332

[0357] Mathematical Formula Example 310< Md3 (DG12 / DG23) < 0.70.030320.5 < TD2 / TTL < 10.633331 < TD1 / TD2 < 1.81.3873420 < TD2 < TD3 < TD1 < 40 Manjok350.1 < BFL2 / TTL < 10.367361 < BFL3 / BFL1 < 31.079373 < TD3 / BFL3 < 86.567382 < Md_CG_Max / Md_CG_Min < 86.586391 < BFL_Min < 64.9794030 < Aver_Vd < 5033.024411.5 < Aver_Nd < 1.81.609421 < 쥅 FG1 / FG2 쥅 < 41.472431 < FMd2 / FMd2 < 101.904442 < FMd2 / EPD2 < 74.704451 < FMd1 / EPD1 < 32.69346FMd1 < FMd2 < FMd3 471 < TTL / FMd2 < 31.873481 < TTL / FMd1 < 53.564491 < CA_Max / ImgH < 32.154505 < TTL / ImgH < 1411.518512 <BFL2 / ImgH < 64.232521 < BFL3 / ImgH < 41.522531 < EPD1 < EPD2 <EPD3 < 7만족540 < Max_Distortion < 31.339558 < FOV3 <FOV2 < FOV1 <45만족

[0358] The optical system and camera module according to the embodiment may satisfy at least one or two of mathematical expressions 1 to 30 and / or mathematical expressions 31 to 55, or may satisfy all mathematical expressions.

[0359] FIG. 15 is a drawing illustrating a camera module according to an embodiment applied to a mobile terminal. Referring to FIG. 15, 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.

[0360] 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.

[0361] 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.

[0362] 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.

[0363]

[0364] FIG. 16 is an example of a plan view of a mobile object or vehicle to which a camera module or optical system according to an embodiment of the invention is applied. Referring to FIG. 16, 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, 25, 26), and a control unit (14). The image generating unit (11) may include at least one camera module (13) 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 (13), 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.

[0365] 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, 25, 26) detects each side of the own vehicle 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), and generates second detection information. Specifically, the second information generating unit (21, 22, 23, 24, 25, 26) 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 generating units (21, 22, 23, 24, 25, 26) can be placed at the front two corners, side mirrors, and rear center and rear two corners of the vehicle, respectively.

[0366] At least one information generating unit of these vehicle camera systems may be equipped with an optical system and a camera module having the same as described in the above-described embodiment(s), 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.

[0367] The optical system of a camera module according to an embodiment of the invention can be installed in multiple units within a vehicle to enhance safety regulations, autonomous driving functions, and convenience. Furthermore, the optical system of the camera module is used as a component for controlling systems 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 achieve stable optical performance even under ambient temperature changes and offer competitive pricing, thereby ensuring the reliability of vehicle components.

[0368]

[0369] 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 those with 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 with 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 within the scope of the present invention defined in the appended claims.

Claims

1. It comprises first to third lens groups arranged along the optical axis from the object toward the sensor side, each group including at least one lens, The above first lens group and the above third lens group have negative power, The second lens group has positive power, The position of the first lens group is fixed, Each of the second and third lens groups is movable along the optical axis according to the operating mode, Among the lenses in the first lens group, the first lens closest to the object has negative power, An optical system in which the absolute value of the effective focal length of the third lens group is greater than the product of the absolute values ​​of the effective focal lengths of the first and second lens groups.

2. In paragraph 1, Among the lenses of the first to third lens groups, the maximum center thickness is CT_Max, and the minimum center thickness is CT_Min. Mathematical formula: 2 < CT_Max / CT_Min < 7 An optical system that satisfies .

3. In paragraph 1, The maximum effective length of the object-side and sensor-side surfaces of the lenses of the first to third lens groups is CA_Max, and the minimum effective length is CA_Min. Mathematical formula: 1< CA_Max / CA_Min <3 An optical system that satisfies .

4. In any one of paragraphs 1 to 3, The optical axis distance of the first lens group is TD1, and the optical axis distance of the second lens group is TD2. Mathematical formula: 1 < TD1 / TD2 < 1.8 An optical system that satisfies .

5. In any one of paragraphs 1 to 3, According to the above operation mode, the maximum center spacing of adjacent lenses among the lenses of the first to third lens groups is Md_CG_Max, and the minimum center spacing is Md_CG_Min. Mathematical formula: 2 < Md_CG_Max / Md_CG_Min < 8 An optical system that satisfies .

6. In any one of paragraphs 1 to 3, The third lens group includes the last lens closest to the image sensor, An optical system in which the last lens has a biconvex shape on the optical axis.

7. In any one of paragraphs 1 to 3, The first lens group includes the first lens closest to the object, An optical system wherein the first lens has a convex meniscus shape toward the object.

8. In any one of paragraphs 1 to 3, The optical axis distance between the last lens closest to the image sensor within the third lens group and the image sensor varies depending on the operating mode. The operating modes of the optical system include wide mode, middle mode and tele mode.

9. In paragraph 8, In the above wide mode, the optical axis spacing between the last lens and the image sensor is BFL1, In the above tele mode, the optical axis distance between the last lens and the image sensor is BFL3, Mathematical formula: 1 < BFL3 / BFL1 < 3 An optical system that satisfies .

10. In paragraph 8, In the above middle mode, the optical axis spacing between the last lens and the image sensor is BFL2, Half of the diagonal length of the effective area of ​​the image sensor is ImgH, Mathematical formula: 2 < BFL2 / ImgH < 6 An optical system that satisfies .

11. In any one of paragraphs 1 to 3, The number of lenses in the first and third lens groups is greater than the number of lenses in the second lens group. An optical system in which the absolute value of the focal length of the first lens group is greater than the focal length of the second lens group.

12. In paragraph 6, The effective focal length of the wide mode of the above optical system is FMd1, The focal length of the first lens is F1, Mathematical formula: 1 < │F1 / FMd1│ < 2 An optical system that satisfies .

13. A first lens group having first to third lenses; A second lens group having fourth and fifth lenses; A third lens group having sixth to eighth lenses, The first to eighth lenses of the first lens group, the second lens group, and the third lens group are arranged in the optical axis direction from the object toward the sensor, The above first lens has negative refractive power and has a convex shape on the object-side surface, The third lens has negative refractive power and has a concave shape on the sensor side. The above fourth lens has a positive refractive power and a biconvex shape, The above eighth lens has negative refractive power and has a biconvex shape, The second lens group and the third lens group are moved in the optical axis direction, The optical axis spacing between the above-mentioned eighth lens and the image sensor varies depending on the operating mode, The refractive index of the above first lens is Nd1, Mathematical formula: 1.6 < Nd1 An optical system that satisfies .

14. In paragraph 13, The above first and third lens groups have negative (-) refractive power, The second and fourth lenses have positive refractive power, The above fourth lens and the above eighth lens are optical systems having a refractive index of less than 1.

6.

15. In paragraph 13 or 14, The effective length of the largest lens surface among the first to eighth lenses is CA_Max, Half of the diagonal length of the image sensor is ImgH, Mathematical formula: 1 < CA_Max / ImgH < 3 An optical system that satisfies .

16. Image sensor; optical system; and It includes a driving member that moves at least one of the plurality of lens groups of the optical system in the direction of the optical axis, The optical system comprises an optical system according to claim 1 or claim 13, A camera module in which the driving member moves the positions of each of the second and third lens groups of the optical system in the direction of the optical axis.

Images