Optical system and camera module

Abstract

An optical system disclosed as an embodiment of the present invention comprises: a first lens group having a first lens having positive refractive power on a first optical axis; second to fourth lens groups having a plurality of lenses on a second optical axis; and a reflective member between the first and second lens groups, wherein each of the second to fourth lens groups has at least two lenses, the third lens group has the lens having the greatest center thickness among the lenses, an object-side surface of the first lens has a convex shape, the effective length of the first lens is greater than the effective lengths of the lenses of the second to fourth lens groups, a first optical axis distance between the first lens and the reflective member is MG1, a second optical axis distance between the reflective member and a lens adjacent to an exit side of the reflective member is MG2, and the condition 2 < MG1 / MG2 < 6 may be satisfied.

Description

Optical system and camera module

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

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

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

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

[0005] When the optical system includes a plurality of lenses, the position of at least one lens or a lens group including at least one lens can be controlled to perform functions such as zoom and autofocus (AF). However, when the lens or the lens group performs the function, the amount of movement of the lens or the lens group can increase exponentially. Accordingly, the optical system has a problem in that a lot of energy may be required to move the lens or the lens group, and a large volume is required considering the amount of movement. In addition, there is a problem in that aberration characteristics are deteriorated due to the movement of the lens or the lens group. Accordingly, there is a problem in that optical characteristics are deteriorated at a specific magnification when performing the zoom or autofocus (AF) function. 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 capable of realizing stable performance and high-resolution images using a prism and multiple lenses. 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: a first lens group having a first lens arranged on a first optical axis and having a positive (+) refractive power; second to fourth lens groups having a plurality of lenses sequentially aligned on a second optical axis different from the first optical axis; and a reflective member arranged between the first lens group and the second lens group, wherein each of the second to fourth lens groups has at least two lenses, the third lens group has a lens having a thickest central thickness among the central thicknesses of the lenses of the first to fourth lens groups, an object-side surface of the first lens has a convex shape, an effective length of the first lens is greater than the effective lengths of the lenses of the second to fourth lens groups, a first optical axis distance between the first lens and the reflective member is MG1, a second optical axis distance between the reflective member and a lens adjacent to the reflective member is MG2, and a condition: 2 < MG1 / MG2 < 6 can be satisfied.

[0008] According to an embodiment of the invention, the second lens group includes second to fourth lenses, the second lenses facing the reflective member, and the second lens group may include a number of lenses having a refractive index of 1.6 or more greater than a number of lenses having a refractive index of less than 1.6.

[0009] According to an embodiment of the invention, the third lens group includes fifth and sixth lenses arranged between the second lens group and the fourth lens group, and the fifth lens may have a central thickness that is the thickest among the lenses and a biconvex shape.

[0010] According to an embodiment of the invention, the fourth lens group includes seventh and eighth lenses arranged between the third lens group and the image sensor, and the object-side surface of the eighth lens may have a critical point. According to an embodiment of the invention, the object-side surface of the eighth lens may have a convex shape, and the sensor-side surface of the eighth lens may have a concave shape. The second lens group may have a greater number of lenses having negative refractive power than lenses having positive refractive power. The focal length of the first lens may be the largest among the focal lengths of the first to fourth lens groups. Each of the third and fourth lens groups may move along the second optical axis of the lenses in the second to fourth lens groups.

[0011] According to an embodiment of the invention, the focal length of the first lens group is FLG1, the focal length of the second lens group is FLG2, and the mathematical formula: │ FLG2│*4 < FLG1 can be satisfied.

[0012] According to an embodiment of the invention, the sensor-side surface of the first lens may have a concave shape, and the object-side surface of the fourth lens group may have a concave shape. The sensor-side surface of the third lens group may have a convex shape, and the sensor-side surface of the second lens group may have a concave shape.

[0013] A camera module according to an embodiment of the invention may include an optical system including the first to fourth lens groups and an image sensor as disclosed above.

[0014] 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 of the movable lens groups and can provide an autofocus (AF) function for a subject. The optical system and camera module according to an embodiment can have a plurality of 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.

[0015] 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 the moving distance of the moving lens groups. Accordingly, the optical system can reduce the moving distance of the moving lens groups according to a change in the operation mode, and can minimize the power consumption required when the lens groups are moved. In addition, the optical system can have at least one lens included in the fixed group and the moving group having a non-circular shape.

[0016] An optical system according to an embodiment of the invention can reduce the thickness of the optical system and shorten the overall length of the optical system while maintaining optical performance by reflecting incident light using a prism. In addition, miniaturization of the camera module of a mobile terminal is possible. The optical system and camera module according to the embodiment can adjust the magnification by moving a lens group other than the first lens group adjacent to the subject among a plurality of lens groups. Accordingly, the optical system can have a constant TTL value even when the lens group is moved according to a change in magnification. Accordingly, the camera module can be provided with a slimmer structure with a folded zoom optical system.

[0017] FIG. 1a is a schematic diagram showing an example of a first mode (Wide mode) of a camera module and an optical system according to an embodiment of the invention.

[0018] Figure 1b is a diagram illustrating the optical system of Figure 1a.

[0019] (a)(b) of Fig. 2 are examples of the operation of the second mode (Middle mode) and the third mode (Tele mode) of the optical system of Fig. 1a.

[0020] Figure 3 is a table of lens data of an optical system according to an embodiment of the invention.

[0021] Figure 4 is a table showing aspherical coefficients of lenses of an optical system according to an embodiment of the invention.

[0022] Figure 5 is a graph showing spherical aberration, astigmatic field curves, and distortion in the optical system of the first mode of Figure 1a.

[0023] Figure 6 is a graph showing spherical aberration, astigmatism curve, and distortion aberration in the optical system of the second mode of Figure 2(a).

[0024] Figure 7 is a graph showing spherical aberration, astigmatism, and distortion aberration in the optical system of the third mode of Figure 2(b).

[0025] Fig. 8 is a graph showing data of the diffraction MTF (Modulation Transfer Function) of the optical system of Fig. 1a.

[0026] Figure 9 is a graph showing the diffraction MTF (Modulation Transfer Function) data of the optical system of Figure 2(a).

[0027] Figure 10 is a graph showing the diffraction MTF (Modulation Transfer Function) data of the optical system of Figure 2(b).

[0028] Fig. 11 is a front view of a combination of a second lens and a reflective member according to an embodiment of the invention.

[0029] FIG. 12 is a perspective view of a camera module combined with an optical system according to an embodiment of the invention.

[0030] FIG. 13 is a perspective view of a mobile terminal having an optical system and a camera module according to an embodiment of the invention.

[0031] FIG. 14 is a plan view showing an example of a mobile body having an optical system and a camera module according to an embodiment of the invention.

[0032] 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.

[0033] 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.

[0034] 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.

[0035] In the specification, the convexity of the lens surface may mean that the lens surface in the area corresponding to the optical axis or the paraxial area has a convex shape based on the optical axis, and the concaveness of the lens surface may mean that the lens surface in the area corresponding to the optical axis or the paraxial area 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.

[0036] Additionally, the invention provides that the lens(es) disposed between the reflective member and the object are aligned with the first optical axis, and the lenses disposed between the reflective member and the image sensor can be aligned with the optical axis or the second optical axis.

[0037]

[0038] As shown in FIGS. 1A and 2, an optical system (100) according to an embodiment of the invention may include a plurality of lens groups and a reflective member (P1). The plurality of lens groups may include at least three lens groups. Each of the plurality of lens groups includes at least one lens. The plurality of lens groups may include first to fourth lens groups (LG1 to LG4).

[0039] The optical system (100) may include first to fourth lens groups (LG1-LG4) sequentially arranged along the optical axis (OA1, 0A2) from the object toward the image sensor (190). For example, the reflective member (P1) changes light incident through the first lens group (LG1) in the direction of the second optical axis (OA2), and the second to fourth lens groups (LG2-LG4) may be aligned with the second optical axis (OA2). The first optical axis (OA1) and the second optical axis (OA2) are orthogonal to each other, and the first optical axis (OA1) is the optical axis of a lens arranged between the reflective member (P1) and the object, and the second optical axis (OA2) is the optical axis of lenses arranged between the reflective member (P1) and the image sensor (190). Here, the optical axis passing through the center of the lenses of the second to fourth lens groups (LG2, LG3, LG4) and the center of the image sensor (190) can be defined as the optical axis (OA2) or the second optical axis.

[0040] The second lens group (LG2) is arranged between the first lens group (LG1) and the third lens group (LG3), and the third lens group (LG3) can be arranged between the second lens group (LG2) and the fourth lens group (LG4). The first lens group (LG1) and the second lens group (LG2) are optical elements that gather light rays, the third lens group (LG3) is an element that changes the zoom magnification of the optical system, that is, the focal length, and the fourth lens group (LG4) is an element that adjusts the focal position of the imaging surface. That is, the fourth lens group (LG4) can perform a role of controlling a chief ray angle (CRA).

[0041]

[0042] The optical system (100) may include n lenses and a reflective member (P1), and the nth lens may be the last lens, and the (n-1)th lens may be the lens closest to the last lens. The n is an integer greater than or equal to 7, for example, 7 to 9. The lenses in the optical system (100) may be defined as lens units. Among the plurality of lens groups, at least two lens groups may be fixed lens groups whose positions are fixed, and at least two lens groups may be variable lens groups whose positions are variable. For example, a first lens group (LG1) adjacent to an object and a second lens group (LG2) adjacent to the first lens group (LG1) may be fixed lens groups, and third and fourth lens groups (LG3, LG4) arranged between the second lens group (LG2) and the image sensor (190) may be variable lens groups. Here, the variable lens group may be moved along the second optical axis (OA) or returned to its original position.

[0043] The optical system (100) can provide a continuous zoom optical system having a first mode, a second mode, and a third mode depending on the shooting mode by the above variable lens group. In addition, the reflective member (P1) arranged between the lens groups can provide a folded zoom optical system. The first mode is a wide mode, the second mode is a middle mode, and the third mode is a tele mode.

[0044] The moving distance of the above-mentioned moving lens groups can be set to a maximum of 7.5 mm or less, thereby reducing the power consumption of the driving member. In addition, when in tele mode, the optical axis distance (CG6) between the third and fourth lens groups (LG3, LG4) can be set to 1 mm or more, thereby reducing the moving distance of the fourth lens group (LG4) and providing a high-magnification optical system. The optical system has a zoom magnification of 1.5 times or more, a focal length of 14 mm or less in wide mode, and a focal length of 16 mm or more in tele mode. The zoom magnification of this optical system can be approximately 2 times.

[0045]

[0046] The number of lenses of the second lens group (LG2) may be at least twice the number of lenses of the first lens group (LG1). The number of lenses of the first and second lens groups (LG1, LG2) is the number of lenses excluding prisms. The number of lenses of the first lens group (LG1) may be 2 or less, for example, 1. The number of lenses of the second lens group (LG2) may be greater than the number of lenses of the third lens group (LG3). The number of lenses of the third lens group (LG3) may be greater than the number of lenses of the first lens group (LG1). The number of lenses of the fourth lens group (LG4) may be greater than the number of lenses of the first lens group (LG1) and less than the number of lenses of the second lens group (LG2). The number of lenses of the second lens group (LG2) is at least 2, for example, in the range of 3 to 4. The number of lenses in each of the third lens group (LG3) and the fourth lens group (LG4) may be the same. By stacking these lens numbers, optical systems in wide mode, middle mode, and tele mode can be provided, and also, depending on the operating mode, a bright optical system with an F number in the range of 2.0 to 4.0 can be provided.

[0047] When in zoom magnification or focusing mode, the maximum movement distance of at least one of the third and fourth lens groups (LG3, LG4) may be 7.5 mm or less, and may be in the range of 2 mm to 7.5 mm or in the range of 2 mm to 6 mm. If the maximum movement distance of the third and fourth lens groups (LG3, LG4) is greater than the above range, the length of the camera module may become longer, and securing optical performance may become difficult. In addition, if it is less than the above range, the zoom magnification may be reduced.

[0048]

[0049] At least one or all of the lenses of the first to fourth lens groups (LG1-LG4) may be made of glass or plastic. Preferably, the lenses of the first to fourth lens groups (LG1-LG4) may be made of plastic. Each of the first to fourth lens groups (LG1-LG4) may have a lens having a refractive index of 1.6 or more. In addition, in the second lens group (LG2), the number of lenses having a refractive index of 1.6 or more may be greater than the number of lenses having a refractive index of less than 1.6. In the specification, the refractive index is the refractive index at the d-line (e.g., 5867.6 nm).

[0050] The lenses in the above-described movable lens groups (LG2, LG3) may be arranged with a plastic material to prevent an increase in power consumption of the driving member. As another example, each of the above-described movable lens groups (LG2, LG3) may include a plastic lens and a glass lens. As another example, the lens closest to the object among the lenses in the first lens group (LG1) that is fixed in position may be made of glass. As another example, the last lens in the fourth lens group (LG4) closest to the image sensor (190) may be made of glass. At least one or all of the lens surfaces of the lenses in the first to fourth lens groups (LG1-LG4) may have an aspherical shape on the optical axis. The lenses having the aspherical surface may prevent spherical aberration in the optical system (100), and since aberration does not occur even when the effective diameter is increased, miniaturization and weight reduction of the camera module may be possible. The aspherical lens may be made of a glass mold or a plastic material.

[0051] The object-side surface of the second lens group (LG2) is a third surface (S3), and the third surface (S3) may have a convex shape toward the object on the second optical axis (OA2). That is, the radius of curvature of the third surface (S3) may have a positive value on the second optical axis (OA2). Since the radius of curvature of the third surface (S3) has a positive value, light loss can be reduced and the beam size can be reduced.

[0052]

[0053] The power of the first lens group (LG1) may have a sign opposite to that of the power of the second lens group (LG2). The power of the first lens group (LG1) may have a positive value, and the power of the second lens group (LG2) may have a negative value. The power of the third lens group (LG3) may have a sign opposite to that of the fourth lens group (LG4). The power of the third lens group (LG3) may have a positive value, and the power of the fourth lens group (LG4) may have a negative value. When each of the second, third, and fourth lens groups (LG2, LG3, and LG4) has two or more lenses, it may include lenses having negative power and lenses having positive power. Accordingly, the lens optical system can correct optical aberrations and improve image quality by mixing lenses having positive power and lenses having negative power. The power of each lens or each lens group above is the reciprocal of the focal length value.

[0054] The focal length of the first lens group (LG1) may be greater than the absolute value of the focal lengths of the second and third lens groups (LG2, LG3). For example, the focal length of the first lens group (LG1) may be at least 3 times, for example, in a range of 3 to 12 times, the absolute value of the focal length of the second lens group (LG2). Accordingly, the first lens group (LG1) may disperse incident light. The absolute value of the focal length of the second lens group (LG2) may be greater than the absolute value of the focal length of the third lens group (LG3). The focal length of the fourth lens group (LG4) may be less than the focal length of the first lens group (LG1) and greater than the focal length of the third lens group (LG3). The focal length of the third lens group (LG3) may be the smallest among the absolute values ​​of the focal lengths of the lens groups. The focal length of the third lens group (LG3) may be smaller than the focal length of the optical system (100).

[0055]

[0056] The focal length of the first lens group (LG1) is FLG1, the focal length of the second lens group (LG2) is FLG2, and the condition of │FLG2│ < FLG1 can be satisfied. The focal length of the third lens group (LG3) is FLG3, and the focal length of the fourth lens group (LG4) is FLG4, and the condition of FLG3 < │FLG4│ can be satisfied. The focal length of the first lens group (LG1) whose position is fixed can be greater than the sum of the absolute values ​​of the focal lengths of the third and fourth lens groups (LG3, LG4) that are moved. The field of view (FOV) can be adjusted by the focal lengths of the first to fourth lens groups (LG1-LG4). The first lens group (LG1) has a first lens (111). The focal length of the first lens group (LG1) may be 40 mm or more, for example, in the range of 40 mm to 300 mm or in the range of 60 mm to 200 mm.

[0057] The above-described reflective member (P1) performs an OIS function and can suppress a decrease in resolution due to the focal length. The reflective member (P1) is arranged between the first lens group (LG1) and the second lens group (LG2). The reflective member (P1) is arranged between the first lens (111) and the second lens (112). The incident surface (PS1) of the reflective member (P1) faces the sensor-side second surface (S2) of the first lens (111), and the object-side third surface (S3) of the second lens (112) faces the exit surface (PS2) of the reflective member (P1). The reflective member (P1) includes a reflective surface (PR1) that reflects light incident on the incident surface (PS1) to the exit surface (PS2). The first optical axis (OA2) of the above reflective surface (PR1) can be inclined in a range of 30 to 60 degrees or 45 degrees.

[0058] The center distance (MG1) between the second surface (S2) of the first lens (111) and the incident surface (PS1) of the reflective member (P1) may be greater than the center distance (MG2) between the object-side third surface (S3) of the second lens (112) and the exit surface (PS2) of the reflective member (P1). Since the distance (MG2) between the exit surface (PS2) of the reflective member (P1) and the second lens (112) is provided to be 1 mm or less, an increase in the effective length or effective diameter of the lenses of the second lens group (LG2) can be suppressed. The effective length of the first lens (111) may be the largest among the effective lengths of the lenses. The effective length is the average of the effective lengths of the object-side surface and the sensor-side surface of each lens. The effective length of the first lens (111) may be greater than the effective length of the incident surface (PS1) of the reflective member (P1) in the third direction (Z). Accordingly, the first lens (111) can increase the amount of light incident on the incident surface (PS1) of the reflective member (P1). Accordingly, the size of the incident pupil of the optical system (100) can be increased, and the resolution can be improved.

[0059]

[0060] The object-side surface or the incident-side surface of the first lens group (LG1) is the first surface (S1) and may have a convex shape on the first optical axis (OA2). The sensor-side surface or the output-side surface of the first lens group (LG1) is the second surface (S2), and the second surface (S2) may have a concave shape on the optical axis (OA1). Since the first surface (S1) has a convex shape, the incidence efficiency of light can be improved.

[0061] For magnification changes, the minimum center distance between lenses in adjacent lens groups can be provided to be 0.1 mm or more, and the maximum center distance can be provided to be 10 mm or less. Accordingly, the overall length (TTL) of the optical system (100) can be reduced. In addition, the center spacing (CG6) between the moving third and fourth lens groups (LG3, LG4) can be provided to be 0.3 mm or more, for example, 0.6 mm or more.

[0062] The effective length of the object-side first surface (S1) of the first lens group (LG1) may be greater than the effective length of the object-side third surface (S3) of the second lens group (LG2). When the effective length of the first surface (S1) is CA11 and the effective length of the third surface (S3) is CA21, the following condition may be satisfied.

[0063] Condition: 1 < CA11 / CA21 < 3

[0064] When the ratio of the first and third surfaces (S1, S3) is greater than the above range, the increase in the amount of incident light is minimal, and when it is less than the above range, the height of the optical system can increase.

[0065]

[0066] The lens closest to the image sensor (190) may have an Abbe number of 45 or greater. The lens closest to the image sensor (190) may have a refractive index of less than 1.6. Accordingly, the resolution of the last lens can be adjusted to control the light path incident on the image sensor (190). Among the lenses of the first to fourth lens groups (LG1 to LG4), the lens with the largest center thickness can be arranged in the third lens group (LG3). Accordingly, the change in the light path caused by the lenses of the third lens group (LG3) can be reduced.

[0067]

[0068] When the sum of the refractive indices of the lenses in the above optical system (100) is ΣNd and the sum of the Abbe numbers is ΣAd, the following conditions can be satisfied.

[0069] Condition 1: 10 < ΣNd < 15 Condition 2: 240 < ΣAd < 330

[0070] By adjusting the refractive index and Abbe number of the lenses within the optical system (100), aberration can be controlled. The lens with the maximum Abbe number can reduce chromatic dispersion, and the lenses with a refractive index of 1.6 or higher can increase the chromatic dispersion of incident light. The number of lenses with a refractive index of 1.6 or higher within the optical system (100) may be greater than the number of lenses with a refractive index of less than 1.6.

[0071] Each of the lenses of the optical system (100) may include an effective area and an ineffective area. The effective area may be an area through which light incident on each of the lenses passes. That is, the effective area may be defined as an effective area or CA (Clear Aperture) through which the incident light is refracted to implement optical characteristics. The ineffective area may be arranged around the periphery of the effective area. The ineffective area may be an area through which effective light is not incident from the plurality of lenses. That is, the ineffective area may be an area unrelated to the optical characteristics. In addition, the edge of the ineffective area may be an area fixed to a lens barrel (not shown) that accommodates the lens.

[0072]

[0073] The average effective length of the object-side and sensor-side surfaces of the lenses of the second to fourth lens groups (LG2-LG4) can be provided as 4 mm or more, for example, in the range of 4 mm to 7 mm. The maximum effective length of the object-side surface (S1) of the first lens (111) can exceed 7 mm and can be provided as greater than the maximum effective length of the sensor-side surface (S16) of the last lens (118). Accordingly, the amount of light incident through the first lens (111) can be increased.

[0074] Among the lenses in the optical system (100), at least one or two or more lenses may have different effective lengths in two directions orthogonal to the optical axis (OA2). For example, the first lens (111) may have the same or different effective lengths in the second direction (Y) and the third direction (Z), which are orthogonal to each other. In addition, at least one or two or more lenses in the second to fourth lens groups (LG2-LG4) may have different effective lengths in the first and second directions (X, Y). Here, the shape of the object-side surface or the sensor-side surface of the lenses having different effective lengths in two orthogonal directions may be non-circular. When the effective lengths of the first lens (111) in the second direction (Y) and the third direction (Z) are different, the effective length of the first lens (111) in the second direction (Y) may be longer than the effective length in the third direction (Z). Accordingly, the length of the lens optical system in the third direction can be reduced. Among the lenses in the second to fourth lens groups (LG2-LG4), the effective lengths of the lenses in the second direction (Y) may be shorter than the effective lengths in the first direction (X). Accordingly, the height of the lens optical system in the second direction (Y) may be reduced, and an increase in the thickness of the camera module and the thickness of the mobile terminal may be prevented. The effective lengths of the lenses in the second to fourth lens groups (LG2-LG4) may be the greatest among the lenses in the fourth lens group (LG4), and at least one of the lenses in the fourth lens group (LG4) may have different effective lengths in the first and second directions (X, Y).

[0075]

[0076] Within the optical system (100), the TTL (Total top length) may be more than 5 times greater than ImgH, and preferably, the condition of 5 < TTL / ImgH < 12 or 7 < TTL / ImgH < 11 may be satisfied. The TTL (Total track length or total top length) is the distance from the center of the object-side surface (S1) of the first lens (111) to the surface of the image sensor (190) along the optical axis (OA1, OA2). The TTL is the sum of the distance (TTL2) from the center of the object-side surface (S1) of the first lens (111) to the reflective surface (PR1) of the reflective member (P1) in the direction of the first optical axis (OA1) and the distance (TTL1) from the reflective surface (RSO) of the reflective member (P1) to the surface of the image sensor (190) in the direction of the optical axis (OA2). ImgH is the length from the center of the image sensor (190) to the diagonal end, or half the diagonal length of the image sensor (190). Here, ImgH, TTL, TTL1, and TTL2 can satisfy the following conditions.

[0077] Condition 1: TTL2*2 < TTL1 Condition 2: 0.6 < TTL1 / TTL < 0.8

[0078] Condition 3: 0.2 < TTL2 / TTL < 0.4 Condition 3: 4mm < ImgH*2 < TTL2

[0079]

[0080] In the optical system (100), the effective focal length (EFL) is provided to be greater than 9 mm and the diagonal field of view (FOV) is provided to be less than 45 degrees, so that it can be provided as a foldable zoom optical system of a portable terminal. Accordingly, the optical system (100) can provide a zoom optical system with high resolution and high magnification. The maximum length of the optical system (100) in the third direction (Z) can be greater than TTL. The maximum length of the optical system (100) in the third direction (Z) is the length in the optical axis direction from one end of the first lens (111) to the image sensor (190). When the maximum length of the optical system (100) in the third direction (Z) is ZL1, the condition: TTL2 < TTL < ZL1 can be satisfied. One end of the third direction (Z) of the first lens (111) may be positioned further outward than one end of the third direction (Z) of the incident surface (PS1) of the reflective member (P1). One end of the third direction (Z) of the first lens (111) may not overlap with the incident surface (PS1) of the reflective member (P1) in the second direction (Y). The other end of the third direction (Z) of the first lens (111) may overlap with the second lens (112) in the second direction (Y).

[0081]

[0082] Among the above lenses, the number of lenses having an effective length greater than the maximum effective length of the image sensor (190) is less than 30%, and may be, for example, in the range of 10% to 20%. The effective length of the lens closest to the object side among the lenses may be greater than the effective length of the image sensor (190). In addition, the effective lengths of the lens (e.g., 114) arranged on the object side of the aperture (ST) and the lens (e.g., 115) arranged on the sensor side of the aperture (ST) may be smaller than the diagonal length of the image sensor (190). Accordingly, the brightness of the optical system can be controlled. By controlling the effective diameter size of each of the lenses, the optical system (100) can control the incident light to compensate for the deterioration of optical characteristics due to resolution and temperature changes, and can improve chromatic aberration control characteristics.

[0083]

[0084] The optical system (100) or camera module may include an image sensor (190). The image sensor (190) may detect light and convert it into an electrical signal. The image sensor (190) may detect light that has sequentially passed through the lens groups (LG1-LG4). The image sensor (190) may include an element capable of detecting incident light, such as a charge-coupled device (CCD) or a complementary metal oxide semiconductor (CMOS). The optical system (100) or camera module may include an optical filter (192). The optical filter (192) may be disposed between the fourth lens group (LG4) and the image sensor (190). The optical filter (192) may be disposed between the lens closest to the sensor side among the lenses and the image sensor (190). For example, the optical system may be placed between the last lens and the image sensor (190). A cover glass (not shown) may be placed between the optical filter (192) and the image sensor (190), and may protect the upper portion of the image sensor (190) and prevent a decrease in the reliability of the image sensor (190). The cover glass may be removed.

[0085] The optical filter (192) may include an infrared filter or an infrared cut-off filter (IR cut-off). The optical filter (192) may allow light of a set wavelength band to pass through and filter out light of a different wavelength band. When the optical filter (192) includes an infrared filter, it may block radiant heat emitted from external light from being transmitted to the image sensor (190). In addition, the optical filter (192) may transmit visible light and reflect infrared light.

[0086] An optical system (100) according to an embodiment may include an aperture (ST). The aperture (ST) may control the amount of light incident on the optical system (100). The aperture (ST) may be disposed between two adjacent lenses of the second and third lens groups (LG2, LG3). In the lenses disposed between an object and the aperture (ST), the effective diameter of the lenses tends to decrease from the object side toward the aperture (ST). The aperture (ST) may be disposed at a set position. The aperture (ST) may be disposed around the object-side surface or the sensor-side surface of one of the lenses of the third lens group (LG3). For example, the aperture (ST) may be disposed around the object-side surface of the third lens group (LG2). As another example, the aperture (ST) may be disposed around the sensor-side surface of the second lens group (LG2).

[0087] The above aperture (ST) may function as an aperture by a portion coated on a non-effective surface area of ​​at least one lens among the lenses of the second and third lens groups (LG2, LG3). In detail, an object-side surface or a sensor-side surface of one lens selected from among the lenses of the optical system (100) may function as an aperture for controlling the amount of light. The optical axis distance between the aperture (ST) and the image sensor (190) is SD, and the value of the SD may vary depending on an operating mode, for example, a wide mode, a middle mode, and a tele mode.

[0088] The fourth lens group (LG4) is moved, and the BFL (Back focal length) value, which is the optical axis distance between the fourth lens group (LG4) and the image sensor (190), may vary depending on the operating mode, for example, wide mode, middle mode, and tele mode. The BLF is the optical axis distance between the center of the last lens and the image sensor (190).

[0089] The camera module (100) can control the movement of the reflective member (P1) by a control signal. Specifically, when shaking occurs in the camera module (100), information about the shaking, such as the degree of rotation and position change of the sensors, can be detected, and compensation for the shaking can be performed. In addition, the camera module (100) can control the driving member by a driving signal to control the movement of the movable lens group, detect position change, and vary the focal length. Accordingly, when photographing a subject located at an infinite or close distance using the camera module (100), shaking due to rotation and position change can be effectively compensated. The camera module (100) according to the embodiment can effectively compensate for shaking due to rotation and shaking due to position change when photographing a subject located at an infinite or close distance. Therefore, the camera module (100) can have improved optical characteristics.

[0090]

[0091] Hereinafter, embodiments will be described with reference to the drawings. Hereinafter, an optical system and a camera module having eight lenses and prisms will be described. For convenience of explanation, a lens adjacent to the object side of the reflective member (P1) is a first lens, and lenses arranged on the sensor side of the reflective member (P1) can be defined as sequentially stacked second to eighth lenses. The center thicknesses of the first to eighth lenses can be defined as CT1 to CT8, the edge thicknesses of the first to eighth lenses can be defined as ET1 to ET8, and the focal lengths of the first to eighth lenses can be defined as F1 to F8. The refractive indices of the first to eighth lenses can be defined as Nd1 to Nd8. The Abbe numbers of the first to eighth lenses can be defined as Ad1 to Ad8. In addition, the center spacing between adjacent 2nd and 3rd lenses is CG2, the center spacing between 3rd and 4th lenses is CG3, the center spacing between 4th and 5th lenses is CG4, the center spacing between 5th and 6th lenses is CG5, the center spacing between 6th and 7th lenses is CG6, the center spacing between 7th and 8th lenses is CG7, and the center spacing between the 8th lens and the image sensor can be defined as BFL.

[0092] In addition, the effective lengths of the object-side surface and the sensor-side surface of the first lens are CA11, CA12, the effective lengths of the object-side surface and the sensor-side surface of the second lens are CA21, CA22, the effective lengths of the object-side surface and the sensor-side surface of the third lens are CA31, CA32, the effective lengths of the object-side surface and the sensor-side surface of the fourth lens are CA41, CA42, the effective lengths of the object-side surface and the sensor-side surface of the fifth lens are CA51, CA52, the effective lengths of the object-side surface and the sensor-side surface of the sixth lens are CA61, CA62, the effective lengths of the object-side surface and the sensor-side surface of the seventh lens are CA71, CA72, and the effective lengths of the object-side surface and the sensor-side surface of the eighth lens can be defined as CA81, CA82. In addition, the average of the effective lengths of the object-side surface and the sensor-side surface of each of the first to eighth lenses can be defined as CA1 to CA8.

[0093]

[0094] An embodiment will be described with reference to FIGS. 1a to 10.

[0095] Referring to FIGS. 1A, 1B, and 5, an optical system (100) according to an embodiment includes first to fourth lens groups (LG1, LG2, LG3, and LG4). The first and second lens groups (LG1, LG2) arranged between an object and a third lens group (LG3) have fixed positions, and the third and fourth lens groups (LG3, LG4) arranged between the second lens group (LG2) and the image sensor (190) have variable positions depending on an operating mode. The operating mode includes a first mode which is a wide mode, a second mode which is a middle mode, and a third mode which is a tele mode, depending on an effective focal length.

[0096] The first lens group (LG1) and the reflective member (P1) refract and reflect incident light toward the second lens group (LG2), and the second lens group (LG2) refracts light emitted through the reflective member (P1) to adjust the brightness of the optical system, the third lens group (LG3) moves along the optical axis (OA2) and changes the zoom magnification (focal length), and the fourth lens group (LG4) moves along the optical axis (OA2) and can adjust the focal position on the image surface of the image sensor (190). The focal lengths of the first to fourth lens groups (LG1-LG4) are defined as FLG1, FLG2, FLG3, and FLG4, and can satisfy the following conditions. In the specification, * represents multiplication.

[0097] Condition 1: │FLG2│*4 < FLG1

[0098] Condition 2: FLG3 < │FLG2│ < FLG3*4

[0099] Condition 3: FLG3 < │FLG4│ < FLG1

[0100] Condition 1 preferably satisfies FLG3*6 < FLG1. It can also satisfy F*3 < FLG1, where F is the minimum effective focal length of the optical system.

[0101]

[0102] The optical system (100) may include a first lens (111), a reflective member (P1), and second to eighth lenses (112-118). The first lens group (LG1) includes the first lens (111), the second lens group (LG2) includes the second to fourth lenses (112, 113, 114), the third lens group (LG3) includes the fifth and sixth lenses (115, 116), and the fourth lens group (LG4) includes the seventh and eighth lenses (117, 118).

[0103] The first lens (111) is disposed on the incident surface (PS1) of the reflective member (P1), and the second lens (111) is disposed on the exit surface (PS2) of the reflective member (P1). The reflective member (P1) is disposed between the first lens (111) and the second lens (112), and reflects light incident through the first lens (111) to the second lens (112).

[0104] The first and third lenses (111, 113) can correct aberrations as they have refractive powers of opposite signs (+, -), and the fifth and sixth lenses (115, 116) can correct aberrations as they have refractive powers of opposite signs (+, -). The seventh and eighth lenses (117, 118) can correct aberrations as they have refractive powers of opposite signs (+, -). The optical axis distance (BFL) between the eighth lens (118) and the image sensor (190) can vary depending on the operating mode, and can provide a space in which the optical filter (192) is installed. In Fig. 4, the first to eighth lenses are L1 to L8, and represent the radius of curvature (R), the conic constant (K), and the aspherical surfaces from the 4th to the 20th order of the lens surfaces (S1 to S16) of each lens. That is, the first to sixteenth surfaces (S1-S16) of the first to eighth lenses (111, 118) may be aspherical.

[0105]

[0106] The first lens (111) may have positive (+) or negative (-) refractive power on the first optical axis (OA), for example, may have positive refractive power. The first lens (111) may include a plastic or glass material, for example, may be a plastic material. The first lens (111) may include a first surface (S1) on the object side and a second surface (S2) on the sensor side. On the first optical axis (OA1), the first surface (S1) may have a convex shape, and the second surface (S2) may have a concave shape. Alternatively, the first surface (S1) may have a concave shape, and the second surface (S2) may have a concave shape.

[0107] The maximum effective length of the first lens (111) may be the longest among the lenses. That is, the effective length of the first surface (S1) of the first lens (111) in the third direction (Z) may be the longest among the lenses. The maximum effective length of the first surface (S1) may be longer than the maximum effective length of the second surface (S2). The average of the effective lengths of the first and second surfaces (S1, S2) may be greater than the average of the effective lengths of the object-side surfaces and the sensor-side surfaces of the second to eighth lenses (112-118). Accordingly, the first lens (111) may improve optical aberrations or control incident light. The first surface (S1) may be provided without a critical point from the optical axis to the end of the effective area. The maximum effective length of the sensor-side first surface (S1) of the first lens (111) in the third direction (Z) may be the largest among the effective lengths of the object-side surface and the sensor-side surface of the second to eighth lenses (112-118).

[0108]

[0109] The above reflective member (P1) is P1 in the lens data of FIG. 3, the incident surface is PS1, and the exit surface is represented by PS2. The reflective surface (PR1) of FIG. 1A intersects the first optical axis (OA1) and the second optical axis (OA2). The reflective member (P1) may be provided as a triangular prism. The reflective member (P1) may be provided with a glass material. In the reflective member (P1), the incident surface (PS1) may be an object-side surface, and the exit surface (PS2) may be a sensor-side surface. The reflective surface (PR1) of the reflective member (P1) reflects light incident to the incident surface (PS1) to the exit surface (PS2), and may be inclined at an angle of 45 degrees with respect to the first optical axis (OA1). The incident surface (PS1) may have a polygonal shape, for example, a square shape. The above-mentioned emission surface (PS2) may have a polygonal shape, for example, a square shape. The above-mentioned reflective member (P1) may have the highest refractive index within the lens optical system. Alternatively, the reflective surface (PR1) of the above-mentioned reflective member (P1) may be inclined at an angle of 43 to 45 degrees with respect to the first optical axis (OA1).

[0110]

[0111] The second lens (112) may have positive (+) or negative (-) refractive power on the second optical axis (OA2), for example, may have positive refractive power. The second lens (112) may include a plastic or glass material, for example, may be a plastic material. The second lens (112) may include a third surface (S3) on the object side and a fourth surface (S4) on the sensor side, and the third surface (S3) may have a convex shape on the second optical axis (OA2), and the fourth surface (S4) may have a convex shape. The second lens (112) may have a convex shape on both sides on the second optical axis (OA2). Alternatively, the second lens (112) may have a meniscus shape that is convex toward the first reflective member (P1) or the object. Alternatively, the second lens (112) may have a convex meniscus shape toward the sensor. Alternatively, the second lens (112) may have a concave shape on both sides.

[0112] The third lens (113) may have a sign opposite to the sign of the refractive power of the second lens (112) on the second optical axis (OA2). That is, the third lens (113) may have negative refractive power. The third lens (113) may include a plastic or glass material, and may be, for example, a plastic material. The third lens (113) may include a fifth surface (S5) on the object side and a sixth surface (S6) on the sensor side. The fifth surface (S5) may have a convex shape on the optical axis (OA2), and the sixth surface (S6) may have a concave shape. The third lens (113) may have a meniscus shape that is convex toward the object. Alternatively, the fifth surface (S5) may have a convex shape, and the sixth surface (S6) may have a convex shape. In contrast, the fifth surface (S5) may have a concave shape, and the sixth surface (S6) may have a convex shape.

[0113]

[0114] The fourth lens (114) may have a negative (-) refractive power on the optical axis (OA2). The fourth lens (114) may include a plastic or glass material, for example, may be a plastic material, and may have a refractive index of less than 1.60. The fourth lens (114) includes a seventh surface (S7) on the object side and an eighth surface (S8) on the sensor side, and the seventh surface (S7) may have a concave shape on the second optical axis (OA2), and the eighth surface (S8) may have a concave shape. That is, the fourth lens (114) may have a concave shape on both sides. Alternatively, the seventh surface (S7) may have a convex shape, and the eighth surface (S8) may have a concave shape. Alternatively, the fourth lens (114) may have a convex shape on both sides.

[0115] The chromatic aberration occurring in the first and second lenses (111, 112) of the third and fourth lenses (113, 114) can be compensated for. The refractive index of the second and third lenses (112, 113) is arranged to be greater than the refractive index of the first lens (111), so as to disperse the incident light. Accordingly, the increase in the center spacing of the second, third and fourth lenses (112, 113, 114) can be suppressed, and the optical axis distance (TD2) of the second lens group (LG2) can be suppressed.

[0116]

[0117] The fifth lens (115) may have positive (+) or negative (-) refractive power on the optical axis (OA2). The fifth lens (115) may have positive refractive power. The fifth lens (115) may have a power with a sign opposite to that of the fourth lens (114) on the second optical axis (OA2). The fifth lens (115) may include a plastic or glass material, and may be made of, for example, a plastic material. The fifth lens (115) may include a ninth surface (S9) on the object side and a tenth surface (S10) on the sensor side. The ninth surface (S9) may have a convex shape on the second optical axis (OA2), and the tenth surface (S10) may have a convex shape. That is, the fifth lens (115) may have a convex shape on both sides on the optical axis (OA2). Alternatively, the fifth lens (115) may have a concave shape on both sides or a convex meniscus shape toward the object or sensor.

[0118] The center thickness (CT4) of the fourth lens (114) may be thinner than the edge thickness (ET4). The center thickness (CT5) of the fifth lens (115) may be thicker than the edge thickness (ET5). Accordingly, the gap between the eighth and ninth surfaces (S8, S9) may be reduced by the concave eighth surface (S8) of the fourth lens (114) and the convex ninth surface (S9) of the fifth lens (115). In other words, the movement distance of the third lens group (LG3) may be increased.

[0119]

[0120] The sixth lens (116) may have positive (+) or negative (-) refractive power on the optical axis (OA2), for example, may have negative refractive power. The sixth lens (116) may include a plastic or glass material, for example, may be a plastic material. The sixth lens (116) may include an eleventh surface (S11) on the object side and a twelfth surface (S12) on the sensor side. The eleventh surface (S11) may have a concave shape on the second optical axis (OA2), and the twelfth surface (S12) may have a convex shape. That is, the sixth lens (116) may have a convex meniscus shape toward the sensor on the second optical axis (OA2). In contrast, the eleventh surface (S11) may have a convex shape on the optical axis (OA2), and the twelfth surface (S12) may have a convex shape on the optical axis (OA2). In contrast, the eleventh surface (S11) may have a concave shape on the optical axis (OA2), and the twelfth surface (S12) may have a concave shape on the optical axis (OA2). In contrast, the eleventh surface (S11) may have a convex shape on the optical axis (OA2), and the twelfth surface (S12) may have a concave shape on the optical axis (OA2).

[0121] The center thickness (CT5) of the fifth lens (115) may be thicker than the center thickness (CT6) of the sixth lens (116). The center thickness (CT6) of the sixth lens (116) may be greater than the center thicknesses of the first to fourth lenses (111-114). The center thickness (CT6) of the sixth lens (116) may be the thickest among the center thicknesses of the lenses. The Abbe number (Ad5) of the fifth lens (115) may be greater than the Abbe numbers of the first to third lenses (111-113). The difference in the Abbe numbers of the third lens (113) and the fifth lens (115) may be greater than 20. Accordingly, the third lens group (LG3) can minimize the change in chromatic aberration caused by the position changing according to the change in the operation mode. The Abbe number (Ad4) of the fourth lens (114) may be greater than 20 of the Abbe number of the third lens (113). The fifth lens (115) and the sixth lens (116) have refractive powers of opposite signs, and when the difference in Abbe numbers is set to be greater than 20, chromatic aberration can be controlled. Accordingly, the third lens group (LG3) can minimize chromatic aberration changes caused by positions that change according to mode changes and perform an achromatic function.

[0122]

[0123] The seventh lens (117) may have positive (+) or negative (-) refractive power on the optical axis (OA2), and may have positive refractive power. The refractive power of the seventh lens (117) has a sign opposite to the sign of the refractive power of the sixth lens (116), so that chromatic aberration can be improved. The seventh lens (117) may include a plastic or glass material, and may be, for example, a plastic material. The seventh lens (117) may include a 13th surface (S13) on the object side and a 14th surface (S14) on the sensor side. The 13th surface (S13) may have a concave shape on the second optical axis (OA2), and the 14th surface (S14) may have a concave shape. That is, the seventh lens (117) may have a concave shape on both sides. Alternatively, the seventh lens (117) may have a convex meniscus shape toward the sensor. Alternatively, the 13th surface (S13) may have a convex shape, and the 14th surface (S14) may have a concave shape. Alternatively, the 13th surface (S13) may have a convex shape, and the 14th surface (S14) may have a convex shape on the optical axis (OA2). Alternatively, the 13th surface (S13) may have a concave shape, and the 14th surface (S14) may have a convex shape.

[0124]

[0125] The eighth lens (118) may have positive or negative refractive power on the optical axis (OA2), for example, may have negative refractive power. The eighth lens (118) may include a plastic or glass material, for example, may be a plastic material. The eighth lens (118) may include a fifteenth surface (S15) on the object side and a sixteenth surface (S16) on the sensor side. The fifteenth surface (S15) may have a convex shape on the second optical axis (OA2), and the sixteenth surface (S16) may have a concave shape. That is, the eighth lens (118) may have a convex meniscus shape toward the object or the reflective member (P1) on the optical axis (OA2). Alternatively, the eighth lens (118) may have a concave shape, and the sixteenth surface (S16) may have a convex shape. The refractive index of the above-mentioned eighth lens (118) is provided to be less than 1.6 and may be less than the refractive index of the above-mentioned seventh lens (117).

[0126] The first to fourteenth surfaces (S1-14) of the first to seventh lenses (111-117) may be provided without a critical point from the optical axis to the end of the effective area. At least one of the fifteenth surface (S15) and the sixteenth surface (S16) may have a critical point within the area from the optical axis to the end of the effective area. For example, the critical point of the fifteenth surface (S15) may be arranged at 30% or more, for example, in the range of 30% to 50% of the effective radius based on the second optical axis (OA2). The sixteenth surface (S16) may be provided without a critical point. Since the fifteenth surface (S15) has a critical point, light may be refracted to different areas of the sixteenth surface (S16) in the area surrounding the critical point. The critical point is a point where the tendency of the Sag value changes. That is, the critical point is the point where the Sag value increases and then decreases on the lens surface, or the point where the Sag value decreases and then increases. The Sag value is the optical axis distance between the straight line perpendicular to the center of each lens surface and the lens surface, and the Sag value has a positive value at a position located on the sensor side relative to the center of each lens surface, and a negative value at a position located on the object side relative to the center of each lens surface.

[0127] Since the 16th surface (S16) of the above-mentioned 8th lens (118) is provided in a concave shape, the incident light can be refracted toward the entire area of ​​the image sensor (190). The effective length of the above-mentioned 8th lens (118) can be provided to be longer than the effective length of the 7th lens (117). The effective length of the above-mentioned 8th lens (118) can be provided to be longer than the effective length of the above-mentioned 6th lens (116).

[0128] The first lens (111) may have an effective length in the third direction (Z) that is shorter than the effective length in the first direction (X). For example, the first lens (111) may have a non-circular shape. The second lens (112) may have an effective length in the second direction (Y) that is shorter than the effective length in the first direction (X). For example, the second lens (112) may have a non-circular shape. In addition, at least one of the third lens (113) to the eighth lens (118) may have a length in the second direction (Y) that is shorter than the length in the first direction (X). For example, the eighth lens (118) may have a non-circular shape.

[0129]

[0130] The central thickness (CT7) of the seventh lens (117) may be the thickest among the central thicknesses of the first to eighth lenses (111-118). The central thicknesses (CT1-CT8) of the first to eighth lenses (111-118) may satisfy the following conditions.

[0131] Condition 1: (CT2 + CT3) < CT1 Condition 2: CT4 < CT5 < CT1

[0132] Condition 3: CT5 < CT6 < CT1*2 Condition 4: CT6 < CT5 < CT7

[0133] Condition 6: CT4 < CT8 < CT7 < CT6

[0134]

[0135] Among the plurality of lens groups (LG1, LG2, LG3, LG4), at least one or all of the third and fourth lens groups (LG2, LG3) can be moved toward the object side or the sensor side along the optical axis (OA2). The camera module may include a driving member (not shown). The driving member includes at least one or a plurality of first driving members arranged on the outside of the third lens group (LG3) and at least one or a plurality of second driving members arranged on the outside of the fourth lens group (LG4), and can move the third lens group (LG3) or / and the fourth lens group (LG4) in the direction of the optical axis (OA2) depending on the operation mode.

[0136] The above operation mode may include a first mode for moving to take pictures with a first magnification, as shown in FIGS. 1A and 1B, and a third mode for moving to take pictures with a second magnification higher than the first magnification, as shown in (b) of FIG. 2. In addition, the operation mode may include a second mode having a magnification between the first and third modes, as shown in (a) of FIG. Here, the first magnification may be the lowest magnification of the optical system (100), and the second magnification may be the highest magnification of the optical system (100). 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.

[0137] The initial operation mode of the camera module 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 third lens group (LG3) and the fourth lens group (LG4) may be positioned at a position defined as a first position (Position 1). In the second mode, each of the third lens group (LG3) and the fourth lens group (LG4) may be positioned at a position defined as a second position (Position 2) that is closer to the object or the reflective member (P1) than the first position. In the third mode, each of the third lens group (LG3) and the fourth lens group (LG3) may be positioned at a position defined as a third position (Position 3) that is closer to the object or the reflective member (P1) than the second position. The second position may be an area between the first and third positions.

[0138] Depending on the operation mode, the center spacing (CG4) between the second and third lens groups (LG2, LG3), the center spacing (CG6) between the third and fourth lens groups (LG3, LG4), and the center spacing (BFL) between the eighth lens (118) and the image sensor (190) can be varied. Accordingly, the optical system (100) can control the positions of some lens groups depending on the operation mode to control the effective focal length and magnification of the optical system (100).

[0139]

[0140] The maximum effective length (CA1) of the first lens (111) is the maximum among the lenses, and the effective length (CA4) of the fourth lens (114) is the minimum among the lenses. The effective length (CA4) of the fourth lens (114) may be 5.5 mm or less. The effective length (CA) of each lens may satisfy the following conditions.

[0141] Condition 1: CA3 < CA2 < CA1 Condition 2: CA4 < CA3 < CA5

[0142] Condition 3: CA6 < CA7 < CA8 Condition 4: CA2 < CA8

[0143] The absolute value difference in the radius of curvature between the ninth surface (S9) and the tenth surface (S10) of the fifth lens (115) may be the smallest among the differences in the radius of curvature (absolute value) between the object-side surface and the sensor-side surface of each lens, and may be, for example, 2 mm or less. Since the center thickness (CT7) of the seventh lens (117) is 2.0 mm or more and the difference in the radius of curvature (absolute value) between the two sides (S13, S14) is provided as small as 2 mm or less, the seventh lens (117) can guide light to the effective area of ​​the eighth lens (118) without significantly changing the path of the incident light.

[0144]

[0145] The optical axis distances of the first lens group (LG1) to the fourth lens group (LG4) are defined as TD1, TD2, TD3, and TD4, and can satisfy the following conditions.

[0146] Condition 1: 1mm < TD1 < 3mm Condition 2: 1mm < TD1 < TD2 < 4mm

[0147] Condition 3: TD2 < TD4 < TD3

[0148]

[0149] In the absolute value of the focal length, the focal length (F1) of the first lens (111) may be the largest among the lenses. The difference (absolute value) in the focal lengths of the first and second lenses (111, 112) may be the largest among the differences in the focal lengths of adjacent lenses. The focal lengths (F1 to F8) of the first to eighth lenses (111 to 118) may satisfy the following conditions.

[0150] Condition 1: |F4|*2 < F2 < F1 Condition 2: F5 < |F6| < F2 < F7

[0151] Condition 3: |F8| < |F3| < F7 < F1

[0152]

[0153] The relationships between CG4, CG6, and BFL in modes 1, 2, and 3 are as follows.

[0154] Mode 1: 2mm < CG6 < BFL < CG4 < 7mm

[0155] Second mode: 1mm < CG6 < CG4 < BFL < 9mm

[0156] Mode 3: 0 < CG4 < CG6 < BFL < 11mm

[0157] In addition, in the first to third modes, CG4 can be defined as W-CG4, M-CG4, and T-CG4, and the condition: T-CG4 < M-CG4 < W-CG4 can be satisfied. In addition, in the first to third modes, CG6 can be defined as W-CG6, M-CG6, and T-CG6, and the condition: T-CG6 < M-CG6 < W-CG6 can be satisfied. In addition, in the first to third modes, BFL can be defined as W-BFL, M-BFL, and T-BFL, and the condition: 3 mm < W-BFL < M-BFL < T-BFL < 11 mm can be satisfied. Here, BFL is the optical axis distance from the sensor-side surface of the fourth lens group (LG4) or the eighth lens (118) to the surface of the image sensor (190).

[0158]

[0159] In the above 1st, 2nd, and 3rd modes, the maximum movement distance of the 3rd and 4th lens groups (LG3, LG4) is the movement distance (mMd13) in the 1st and 3rd modes, and is defined as Max_mMd13, and can satisfy Max_mMd13 ≤ 7.5 mm, and preferably, 2 mm < Max_mMd13 < 7 mm. Accordingly, the maximum movement distance for the zoom magnification can be reduced, thereby reducing the power consumption of the driving member. Depending on the operation mode, the F number of the optical system (100) provides a brightness of 4.0 or less, and the F number can be in the range of 2.0 to 4.0. The aperture can be positioned between the 2nd lens group (LG2) and the 3rd lens group (LG3), and can be arranged, for example, around the ninth surface (S9) of the 5th lens (115).

[0160]

[0161] Fig. 3 is an example showing values ​​of an optical system according to an embodiment, in which lenses are defined as L1-L8, a reflective member is P1, and the values ​​show the radius of curvature of each lens, the thickness (CT) of each lens and reflective member on the optical axis, the spacing (CG) on the optical axis between adjacent lenses, the effective length (CA) of each lens surface (S1-S16), the Abbe number (Ad), the refractive index (Nd), and the effective focal length (FL) of each lens. Fig. 4 shows the conic constant (K) of the object-side surface and the sensor-side surface of the first to eighth lenses (111-118) of Fig. 1a and the aspherical coefficients from the 4th to the 20th (AI).

[0162] Table 1 shows the items of the mathematical formulas described above in the optical system (100) of the embodiment, and shows the TTL (Total track length) of the optical system (100), the focal length of each lens group (FLG1-FLG4), ImgH (mm), and the optical axis distance (TD1, TD2, TD3, TD4) of each lens group. The optical axis distance of each lens group is the optical axis distance from the object side surface of each lens group to the sensor side surface.

[0163] Item Example 1 Item Example FLG1 (mm) 90.00 TD1 (mm) 2.50 FLG2 (mm) -14.29 TD2 (mm) 2.79 FLG3 (mm) 6.83 TD3 (mm) 4.97 FLG4 (mm) -14.77 TD4 (mm) 3.72 ImgH (mm) 3.528 TTL (mm) 34.969

[0164] Table 2 shows the effective focal length (F), field of view (FOV), F number (Fno), entrance pupil size (EPD), optical axis distance from the aperture to the sensor side of the last lens, SD, and center spacing (CG4, CG6) between adjacent lens groups of the optical system according to the first to third modes in the optical system according to the embodiment.

[0165] Item 1 Mode 2 Mode 3 Mode F (mm) 11.75 4 15.66 3 19.57 3 CG4 (mm) 4.55 9 2.62 40.90 3 CG6 (mm) 2.99 21.71 5 1.32 7 BFL (mm) 4.19 27.40 3 9.51 6 EPD (EPD1 / EPD2 / EPD3) 4.88 7 5.36 25.87 3 Fno (Fno1 / Fno2 / Fno3) 2.40 4 9 2.92 14 3.33 45 FOV (degrees) 33.86 3 25.40 4 20.30 4 SD (mm) 15.87 215.87 215.87 2

[0166]

[0167] FIGS. 5 to 7 are graphs measuring spherical aberration (Longitudinal Spherical Aberration), astigmatic field curves, and distortion from left to right in an aberration graph of an optical system according to an embodiment. In FIGS. 5 to 7, the X-axis may represent a focal length (mm) and a degree of distortion (%), and the Y-axis may represent the height of the image. In addition, the graph for spherical aberration is a graph for light in wavelength bands of about 435 nm, about 486 nm, about 546 nm, about 587 nm, and about 656 nm, and the graphs for astigmatic aberration and distortion aberration are graphs for light in wavelength bands of 546 nm. In the aberration diagram, it can be interpreted that the closer each curve is to the Y-axis, the better the aberration correction function, and it can be seen that the aberration change according to the operating mode (wide, mid, tele modes) is not large.

[0168] FIGS. 8 to 10 are graphs showing the diffraction MTF (Modulation Transfer Function) in the first mode, second mode, and third mode of the optical system according to an embodiment, and are graphs showing the modulation ratio according to the spatial frequency.

[0169] The camera module according to the embodiment has improved resolution and can have good optical performance not only at the center but also at the periphery of the field of view (FOV). The lens optical system according to the embodiment of the invention is composed of eight lenses and a prism, so that it is compact and lightweight, and at the same time, spherical aberration, astigmatism, distortion aberration, chromatic aberration, and coma aberration are all well corrected, enabling high resolution implementation, and thus can be incorporated into the optical device of a camera and utilized.

[0170]

[0171] An example of a non-circular shape of the second lens (112) according to an embodiment will be described. As shown in FIGS. 1A, 1B, and 11, each of the third surface (S3) and the fourth surface (S4) of the second lens (112) may have a non-circular shape in which the effective lengths in the first direction (X) and the second direction (Y) are different from each other. Specifically, the fourth surface (S4) of the second lens (112) may satisfy the condition: CA4x > CA4y when the effective length in the first direction (X) is CA4x and the effective length in the third direction (Z) is CA4y. Similarly, the third surface (S3) of the second lens (112) may satisfy the condition: CA3x > CA3y when the effective length in the first direction (X) is CA3x and the effective length in the second direction (Y) is CA3y. Based on the center of the fourth surface (S4), both ends in the first direction (X) may be provided as convex curved surfaces, and both ends in the second direction (Y) may be provided as flat surfaces. In addition, when the effective length of the emission surface (PS2) of the reflective member (P1) in the first direction (X) is RA2x and the effective length in the second direction (Y) is RA2y, the condition: RA2x < CA4x or RA2y < CA4y may be satisfied. Accordingly, an increase in the thickness of the optical system (100) may be suppressed.

[0172]

[0173] The optical system (100) according to the embodiment can satisfy at least one or two or more of the mathematical equations described below. Accordingly, the optical system (100) according to the embodiment can effectively correct aberrations that change according to changes in the operating mode. The optical system (100) can adjust the zoom magnification for a subject at various magnifications and can have a slim and compact structure.

[0174] Hereinafter, the spacing between two adjacent lenses can be distinguished into the spacing along the optical axis and the edge spacing. The effective length of each lens or each lens surface (object-side surface or sensor-side surface) is expressed as the effective diameter if it is circular, and as the maximum effective length if it is non-circular. The thickness is the optical axis or center thickness, and the units of the spacing, thickness, effective diameter, focal length, etc. are mm.

[0175] [Mathematical Formula 1] 40 mm < FLG1

[0176] In mathematical expression 1, FLG1 is the focal length of the first lens group (LG1). Here, the focal length of the first lens group (FLG1) may be greater than the focal lengths of the second to fourth lens groups (FLG2, FLG3, FLG4). Mathematical expression 1 may satisfy 60 mm < FLG1 < 250 mm.

[0177] [Mathematical Formula 2] 0 < L1R1*L2R2

[0178] In mathematical expression 2, L1R1 is the radius of curvature of the object-side first surface (S1) of the first lens (111), and L1R2 is the radius of curvature of the sensor-side second surface (S2) of the first lens (111). Since the first surface (S1) and the second surface (S2) have positive values, the amount of incident light can be increased. Mathematical expression 2 can satisfy L1R1 < L1R2.

[0179] [Mathematical Formula 3] 1 < CT1 / CT2 < 5

[0180] In mathematical expression 3, the central thickness (CT1) of the first lens (111) is greater than the central thickness (CT3) of the second lens (112), and when this is satisfied, the aberration characteristics in the optical system (100) can be improved. Preferably, 2 < CT1 / CT2 < 4 can be satisfied.

[0181] [Equation 4] 2 < CT1 / CT3 < 7

[0182] In mathematical expression 4, the central thickness (CT1) of the first lens (111) may be greater than the central thickness (CT3) of the third lens (113), and when this is satisfied, the optical system (100) may improve aberration characteristics. Mathematical expression 4 may preferably satisfy 3 < CT1 / CT3 < 6.

[0183] [Mathematical Formula 4-1] 3mm < (CT5 + CT7) < 8mm

[0184] In mathematical expression 4-1, since the sum of the central thickness (CT5) of the fifth lens (115) of the third lens group (LG3) and the central thickness (CT7) of the seventh lens (117) of the fourth lens group (LG4) exceeds 3 mm, the chromatic aberration characteristics of light traveling through the third and fourth lens groups (LG3, LG4) can be improved. Mathematical expression 4-1 can preferably satisfy 4 mm < (CT5 + CT7) < 7 mm.

[0185] [Mathematical Formula 4-2] 5mm < (TD3 + TD4) < 12mm

[0186] In mathematical expression 4-2, since the sum of the optical axis distance (TD3) of the third lens group (LG3) and the optical axis distance (TD4) of the fourth lens group (LG4) exceeds 5 mm, the chromatic aberration characteristics of light traveling through the third and fourth lens groups (LG3 and LG4) can be improved. Mathematical expression 4-2 can preferably satisfy 6 mm < (TD3 + TD4) < 10 mm.

[0187]

[0188] [Equation 5] 0.5 < CT6 / CT5 < 2

[0189] In mathematical expression 5, the central thickness of the lenses of the third lens group (LG3) can be set, and when this is satisfied, the optical system (100) can improve aberration characteristics. Mathematical expression 5 can preferably satisfy 0.5 < CT5 / CT1 < 1.

[0190] [Equation 6] L2R1*L2R2 < 0

[0191] L2R1 is the radius of curvature of the object-side third surface (S3) of the second lens (112), and L2R2 is the radius of curvature of the sensor-side fourth surface (S4) of the second lens (112). When the optical system satisfies mathematical expression 6, an increase in the gap between the second and third lenses (112, 113) can be suppressed. Preferably, L2R2 < 0 can be satisfied.

[0192] [Equation 7] FLG4 < 0

[0193] In mathematical expression 7, FLG4 is the effective focal length of the fourth lens group (LG4), and can have a value less than 0. FLG4 is the composite focal length of the seventh and eighth lenses. When mathematical expression 7 is satisfied, the optical aberration of the fourth lens group (LG4) of the optical system can be improved.

[0194] [Equation 8] 7 < TTL / TD1 < 15

[0195] In mathematical expression 8, TD1 is the optical axis distance of the first lens group (LG1) or the first lens (111), for example, the optical axis distance from the center of the object-side first surface (S1) of the first lens (111) to the center of the sensor-side second surface (S2). TTL refers to the distance on the optical axis from the object-side first surface (S1) of the first lens (111) to the upper surface of the image sensor (190). When the optical system (100) satisfies mathematical expression 8, the optical system (100) has a relatively small TTL and can secure a peripheral light ratio. Mathematical expression 8 can preferably satisfy 10 < TTL / TD1 < 15.

[0196] [Equation 9] 2 < TTL / EPD3 < 7

[0197] In mathematical expression 9, EPD3 refers to the size of the entrance pupil (EPD: Entrance Pupil Diameter) of the optical system (100) when operating in the third mode, i.e., Tele mode. When the optical system (100) satisfies mathematical expression 9, the optical system (100) can secure a bright image when operating in the third mode, and may be a minimum condition for securing an F number of 4.0 or less in Tele mode. Preferably, 4 < TTL / EPD3 < 7 can be satisfied.

[0198]

[0199] [Equation 10] 2 < CT_Max / CT_Min < 9

[0200] 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, 4 < CT_Max / CT_Min < 8 can be satisfied.

[0201] [Mathematical Formula 11] 1 < CA_Max / CA_Min < 3

[0202] In mathematical expression 11, CA_Max is the largest effective length among each lens surface (S1-S16), and CA_Min is the smallest effective diameter among each lens surface (S1-S16). 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, 2 < CA_Max / CA_Min < 3 can be satisfied.

[0203] [Equation 12] 0.1 < ΣCT / TTL < 0.8

[0204] In Equation 12, ΣCT is the sum of the central thicknesses of the lenses. If the optical system satisfies Equation 12, the size of the optical system and camera module can be reduced. Preferably, 0.2 < ΣCG / TTL < 0.5 can be satisfied.

[0205] [Equation 13] 0.5 < TD1 / TD2 < 1.5

[0206] In mathematical expression 13, TD1 is the optical axis distance of the first lens group (LG1), and TD2 is the optical axis distance of the second lens group (LG2). By setting the optical axis distances of the first and second lens groups (LG1, LG2) in mathematical expression 13, TTL can be adjusted. Preferably, 0.5 < TD1 / TD2 < 1 can be satisfied.

[0207] [Equation 14] 0.5 < TD2 / TD4 < 1.5

[0208] In mathematical expression 14, TD2 is the optical axis distance of the second lens group (LG2), and TD4 is the optical axis distance of the fourth lens group (LG4). Preferably, 0.8 < TD2 / TD4 < 1 can be satisfied. When the optical system (100) 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.

[0209] [Equation 15] 0 < CG2 / TD2 < 0.2

[0210] In mathematical expression 15, CG2 is the optical axis distance between the second lens (112) and the third lens (113). When the optical system (100) satisfies mathematical expression 15, the optical system (100) has a relatively small TTL and can have improved optical characteristics by controlling stray light incident on the first lens group (LG1). Preferably, 0 < CG2 / TD2 < 0.1 can be satisfied.

[0211] [Mathematical Formula 16] 2 < TTL / (TD3 + TD4) < 7

[0212] Mathematical expression 16 sets the sum of the optical axis distances of the TTL and the third and fourth lens groups (LG3, LG4), and when the optical system (100) satisfies Mathematical expression 16, the optical system (100) has a relatively small TTL and can improve chromatic aberration characteristics. Preferably, 3 < TTL / (DLG2+DLG3) < 6 can be satisfied.

[0213]

[0214] [Equation 17] 20 < |Ad4 - Ad2| < 50

[0215] In mathematical expression 17, Ad2 represents the Abbe number of the second lens, and Ad4 represents the Abbe number of the fourth lens. When the absolute value of the difference in Abbe numbers between the second and fourth lenses according to the embodiment satisfies mathematical expression 17, the optical system (100) can improve chromatic aberration characteristics.

[0216] [Equation 18] 15 < |Ad8 - Ad6| < 50

[0217] In mathematical expression 18, Ad8 represents the Abbe number of the eighth lens, and Ad6 represents the Abbe number of the sixth lens. If the absolute value of the difference in Abbe numbers between the sixth and eighth lenses satisfies mathematical expression 18, the optical system (100) can improve chromatic aberration characteristics. Preferably, the conditions of Ad6 < Ad8 and 45 < Ad8 can be satisfied.

[0218] [Equation 19] 1.65 < Nd2

[0219] In mathematical expression 19, Nd2 represents the refractive index of the second lens at the d-line. The second lens can be provided with a high refractive index, thereby dispersing the incident light and securing an effective area of ​​the lens positioned closer to the sensor than the second lens.

[0220] [Equation 20] 2 < MG1 / MG2 < 6

[0221] MG1 is the distance between the first lens and the reflective member along the first optical axis (OA1). MG2 is the distance between the second lens and the reflective member along the second optical axis (OA2). When mathematical expression 20 is satisfied, the distance between the reflective member and the first and second lenses can be set. Preferably, 3 < MG1 / MG2 < 5 can be satisfied. Preferably, the condition: 1 mm < MG1 or 2 mm < MG1 can be satisfied.

[0222]

[0223] [Equation 21] 0.5 < CA_LG2 / ImgH < 1.5

[0224] CA_LG2 is the average of the effective lengths of the lenses in the second lens group. If Equation 21 is satisfied, the incident light can be guided to the effective area of ​​the image sensor. Preferably, 1 < CA_LG2 / ImgH < 1.5 can be satisfied.

[0225] [Equation 22] 4 < F1 / FMd1 <15

[0226] In Equation 22, FMd1 is the effective focal length of the optical system in the first mode. If Equation 22 is satisfied, the length of the TTL can be adjusted. Preferably, 5 < F1 / FMd1 < 10 can be satisfied.

[0227] [Equation 23] 0.5 < |FLG2 / FMd1| < 4

[0228] In mathematical expression 23, the focal length of the second lens group and the focal length of the optical system in the first mode can be set, and if this is satisfied, the optical axis distance of the second lens group can be adjusted. Preferably, 1 < |FLG2 / FMd1| < 2 can be satisfied.

[0229] [Equation 24] 0.2 < |L4R1 / L4R2| < 3

[0230] In mathematical expression 24, L4R1 and L4R2 can set the radius of curvature of the seventh surface (S7) and the radius of curvature of the eighth surface (S8) of the fourth lens on the second optical axis (OA2). When the optical system (100) satisfies mathematical expression 24, the optical path that proceeds to the second and third lens groups can be set.

[0231] [Mathematical Formula 25] 1 < L1R1 / L8R2 < 10

[0232] L8R1 represents the radius of curvature of the sensor-side sixteenth surface (S16) of the eighth lens on the second optical axis (OA2). Preferably, 2 < L1R1 / L8R2 < 5 can be satisfied. When mathematical expression 25 is satisfied, the light path passing through the first lens and the eighth lens can be controlled.

[0233]

[0234] [Equation 26] 0 < Md12_MLG3 / TTL < 0.5

[0235] In mathematical expression 26, Md12_mLG3 refers to the difference in the center spacing after the movement of the third lens group (LG3) when changing from the second mode to the first mode or from the first mode to the second mode. In detail, the Md12_mLG3 represents the movement distance of the third lens group (LG3) in the first and second modes, and refers to the difference value between the optical axis spacing between the second and third lens groups (LG2, LG3) in the first mode and the optical axis spacing between the second and third lens groups (LG3, LG4) in the second mode. When the optical system (100) satisfies mathematical expression 26, the optical system (100) can minimize the movement distance of the third lens group (LG3) when the magnification is changed, and thus the optical system (100) can have a slim structure. In addition, since the movement distance can be minimized when controlling the position of the third lens group (LG3), it can have improved power consumption characteristics. Preferably, 0 < Md12_mLG3 / TTL < 0.1 can be satisfied.

[0236] [Equation 27] 0 < Md23_mLG3 / TTL < 0.5

[0237] In mathematical expression 27, Md23_mLG3 refers to the difference in the center spacing after movement of the third lens group (LG3) when operating from the second mode to the third mode, or from the third mode to the second mode. Specifically, Md23_mLG3 refers to the difference value between the optical axis spacing between the second and third lens groups (LG2, LG3) in the second mode and the optical axis spacing between the second and third lens groups (LG2, LG3) in the third mode. The maximum movement distance of the third lens group (LG3) may be smaller than the maximum movement distance of the fourth lens group (LG4). When the optical system (100) according to the embodiment satisfies mathematical expression 27, the optical system (100) can minimize the movement distance of the third lens group (LG3) when the magnification is changed, so that the optical system (100) can have a slim structure. In addition, the movement distance can be minimized when controlling the position of the third lens group (LG3), thereby providing improved power consumption characteristics. 0.1 < Md23_mLG3 / TTL < 0.1 can be satisfied. In addition, the condition of Md23_mLG3 < Md12_mLG3 can be satisfied.

[0238]

[0239] [Equation 28] 0.1 < Md12_mLG3 / TD3 < 0.6

[0240] Mathematical expression 28 can set the movement distance (Md12_mLG3) of the third lens group (LG3) and the optical axis distance (TD3) of the third lens group (LG3) in the first and second modes. When the optical system (100) satisfies Mathematical expression 26, the optical system (100) can minimize the movement distance of the second lens group (LG2) when the magnification is changed, so that the optical system (100) can have a slim structure. In addition, the movement distance can be minimized when controlling the position of the second lens group (LG2), so that it can have improved power consumption characteristics. Preferably, 0.25 < Md12_mLG3 / TD3 < 0.5 can be satisfied.

[0241] [Equation 29] 0.1 < Md23_mLG3 / TD3 < 0.5

[0242] In mathematical expression 29, Md23_mLG3 refers to the difference in the center spacing after the movement of the third lens group (LG3) when changing from the second mode to the third mode, or from the third mode to the second mode. When the optical system (100) satisfies mathematical expression 29, the optical system (100) can minimize the movement distance of the third lens group (LG3) when the magnification is changed, so that the optical system (100) can have a slim structure. In addition, the movement distance can be minimized when controlling the position of the third lens group (LG3), so that it can have improved power consumption characteristics. Preferably, 0.2 < Md23_mLG3 / TD3 < 0.45 can be satisfied.

[0243] [Equation 30] 0 < Md23_mLG4 / TTL < 0.3

[0244] In mathematical expression 30, Md23_mLG4 refers to the difference in the center spacing after movement of the fourth lens group (LG4) when operating from the second mode to the third mode, or from the third mode to the second mode. Specifically, Md23_mLG4 refers to the difference between the optical axis spacing between the fourth lens group (LG) and the image sensor (190) in the second mode and the optical axis spacing between the fourth lens group (LG4) and the image sensor (190) in the third mode. When the optical system (100) satisfies mathematical expression 25, the optical system (100) can minimize the movement distance of the fourth lens group (LG4) when the magnification is changed, so that the optical system (100) can have a slim structure. In addition, since the movement distance can be minimized when controlling the position of the fourth lens group (LG4), it can have improved power consumption characteristics. 0 < Md23_mLG4 / TTL < 0.1 can be satisfied.

[0245] [Equation 31] 0.1 < Md12_mLG4 / TD4 < 1

[0246] Mathematical expression 31 can set the movement distance of the fourth lens group (LG4) in the first and second modes and the optical axis distance of the fourth lens group (LG4). When the optical system (100) satisfies Mathematical expression 26, the optical system (100) can minimize the movement distance of the third lens group (LG3) when the magnification is changed, so that the optical system (100) can have a slim structure. In addition, the movement distance can be minimized when controlling the position of the fourth lens group (LG4), so that it can have improved power consumption characteristics. Preferably, 0.3 < Md12_mLG4 / TD4 < 0.7 can be satisfied.

[0247]

[0248] [Equation 32] 1 < Md1(CG4 / CG6) < 3

[0249] In mathematical expression 32, Md1(CG4 / CG6) represents the ratio between the center spacing (CG4) between the second and third lens groups in the first mode and the center spacing (CG6) between the third and fourth lens groups. When the optical system (100) according to the embodiment satisfies mathematical expression 30, the optical system (100) may have improved optical characteristics at the first magnification. In detail, the optical system (100) 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, 1.2 < Md1(CG4 / CG6) < 1.8 may be satisfied.

[0250] [Equation 33] 0.2 < Md3(CG4 / CG6) < 0.9

[0251] In mathematical expression 33, Md3(CG4 / CG6) represents the ratio between the center spacing (CG4) between the first and second lens groups and the center spacing (CG6) between the second and third lens groups in the third mode. When the optical system (100) according to the embodiment satisfies mathematical expression 33, the optical system (100) can have improved optical characteristics at the second magnification. In detail, the optical system (100) can have improved aberration characteristics at the second magnification and improve the optical performance of the peripheral portion of the field of view (FOV). Preferably, 0.5 < Md3(CG4 / CG6) < 0.8 can be satisfied.

[0252]

[0253] [Mathematical Formula 34] 2mm < Max_mMd13 ≤ 7.5mm

[0254] Max_mMd13 is the maximum center spacing between adjacent lenses when the third and fourth lens groups (LG3, LG4) move according to the first to third modes. When mathematical expression 34 is satisfied, the center spacing between lenses in an optical system having a variable lens group can be set, and the power consumption of the driving member due to movement can be reduced. Preferably, 3 mm < Max_mMd13 < 7 mm can be satisfied.

[0255] [Equation 35] 1 < CA11 / CA21 < 3

[0256] CA11 is the effective length of the object-side surface (S1) of the first lens, and CA21 is the effective length of the third surface (S3) of the second lens. When mathematical expression 35 is satisfied, the effective lengths of the incident-side lens and the output-side lens can be set based on the reflective member. Preferably, 1.5 < CA11 / CA21 < 2.5 can be satisfied.

[0257] [Equation 36] 0.5 < CA21 / CA82 < 1.5

[0258] CA21 is the effective length of the object-side third surface (S3) of the second lens, and CA82 is the effective length of the sensor-side sixteenth surface (S16) of the eighth lens. When mathematical expression 36 is satisfied, the effective lengths of the lens surfaces arranged on both sides between the reflective member and the image sensor can be set. Preferably, 0.5 < CA21 / CA82 < 1 can be satisfied.

[0259] [Mathematical Formula 37] Md3_Fno ≤ 4.0

[0260] Md3_Fno is the F number of the optical system in the third mode. If the optical system satisfies Equation 36, it can provide a bright optical system.

[0261]

[0262] [Mathematical Formula 38] 6mm < Md3_BFL < 12mm

[0263] Md3_BFL is T-BFL, and is the optical axis distance between the fourth lens group and the image sensor in the third mode. When the optical system satisfies Equation 38, the fourth lens group (LG4) is positioned within the above range relative to the image sensor in tele mode, thereby reducing power consumption of the driving element and suppressing optical loss.

[0264] [Equation 39] 0.5 < BFL_Min / ImgH < 1.5

[0265] BFL_Min represents the minimum BFL value among the first to third modes, and is, for example, the optical axis distance between the eighth lens and the image sensor in the first mode. ImgH is half the diagonal length of the image sensor. If mathematical expression 39 is satisfied, the minimum distance between the image sensor and the last lens can be set. In addition, the minimum BFL required for a high-pixel image sensor can be secured. Preferably, 1 < BFL_Min / ImgH < 1.5 can be satisfied.

[0266] [Equation 40] 5 < TTL / ImgH < 12

[0267] When the optical system (100) satisfies mathematical expression 40, the optical system (100) can have a smaller TTL, so that the optical system (100) can be provided in a slim and compact manner. Preferably, it can be in the range of 7 < TTL / ImgH < 11.

[0268] [Mathematical Formula 41] 2mm < ImgH

[0269] Mathematical expression 41 can set half of the diagonal length of the image sensor (190) and provide the size of the image sensor of the zoom magnification optical system. Mathematical expression 41 can preferably satisfy 3 mm < ImgH < 6 mm.

[0270] [Equation 42] 3 < │ FLG1 / FLG2 │ < 15

[0271] In mathematical expression 42, FLG1 represents the focal length of the first lens group (LG1), and FLG2 represents the focal length of the second lens group (LG2). If mathematical expression 42 is satisfied, the size of the optical system, for example, TTL, can be reduced. Preferably, 0 < FLG1 and FLG2 < 0. Preferably, 3 < │ FLG1 / FLG2 │ < 10 can be satisfied.

[0272] [Mathematical Formula 43] 0 < FMd3 / FMd1 < 1

[0273] In mathematical expression 43, FMd1 is the effective focal length of the optical system in the first mode, and FMd3 is the effective focal length of the optical system in the third mode. Preferably, 0.2 < FMd3 / FMd1 < 0.8 can be satisfied. When the optical system satisfies mathematical expression 43, the effective focal length can be adjusted according to the first and third modes.

[0274] [Equation 44] 2 < FMd2 / EPD2 < 6

[0275] 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 of the optical system (100) in the second mode. When the optical system (100) according to the embodiment satisfies mathematical expression 44, the optical system (100) can secure a bright image when operating in the second mode. Preferably, 2 < FMd2 / EPD2 < 4 can be satisfied.

[0276] [Mathematical Formula 45] 1 < FMd1 / EPD1 < 4

[0277] In mathematical expression 45, 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 (100) when operating in the first mode. When the optical system (100) according to the embodiment satisfies mathematical expression 45, the optical system (100) can secure a bright image when operating in the first mode. Preferably, 2 < FMd1 / EPD1 < 3 can be satisfied.

[0278] [Equation 46] 1 < CA_Max / ImgH < 4

[0279] In mathematical expression 46, CA_Max means the largest effective length (CA) among the lens surfaces of the plurality of lenses included in the optical system (100). ImgH is half of the diagonal length of the image sensor (190), and means half of the maximum diagonal length of the effective area of ​​the image sensor (190). When the optical system (100) according to the embodiment satisfies mathematical expression 46, the optical system (100) can be provided in a slim and compact manner. In addition, the optical system (100) can implement high resolution and high image quality. Preferably, 2 < CA_Max / ImgH < 4 can be satisfied.

[0280]

[0281] [Mathematical Formula 47] 2 < FMd1 / ImgH < 6

[0282] When the optical system (100) according to the embodiment satisfies mathematical expression 47, the effective focal length of the first mode can be set according to the effective length of the image sensor. Preferably, 3 < FMd1 / ImgH < 4 can be satisfied.

[0283] [Mathematical Formula 48] 4 < FMd3 / ImgH < 10

[0284] When the optical system (100) according to the embodiment satisfies mathematical expression 48, the effective focal length (FMd3) can be set in the third mode of the optical system for the effective area of ​​the image sensor. Preferably, 4 < FMd3 / ImgH < 7 can be satisfied.

[0285] [Mathematical Formula 49] 1 < FMd3 / Max_mMd13 < 5

[0286] FMd3 is the effective focal length of the optical system in the third mode, and Max_mMd13 can set the maximum movement distance in the first to third modes. Preferably, 3 < FMd3 / Max_mMd13 < 4.5 can be satisfied.

[0287]

[0288] [Mathematical Formula 50] 10mm < TTL < 50mm

[0289] TTL refers to the distance from the center of the first surface (S1) of the first lens to the surface of the image sensor (190) along the optical axis (OA1, OA2). In mathematical expression 50, by setting TTL to exceed 10 mm, a zoom magnification optical system can be provided. Preferably, 25 mm < TTL < 45 mm can be satisfied.

[0290] [Mathematical Formula 51] 8° < FOV3 < FOV2 < FOV1 < 45°

[0291] In mathematical expression 51, FOV (Field of view) means the angle of view (Degree) in the diagonal direction of the optical system (100), FOV1 is the angle of view in the first mode, FOV2 is the angle of view in the second mode, and FOV3 represents the angle of view in the third mode, and can be set in the order of the angles of wide, middle, and tele modes depending on the operation mode. Preferably, 10° < FOV2 < 30° can be satisfied.

[0292] [Mathematical Formula 52] 3 < EPD1 < EPD2 < EPD3 < 9

[0293] EPD refers to the diagonal angle of view (Degree) of the optical system (100), EPD1 represents the size of the entrance pupil in the first mode, EPD2 represents the size of the entrance pupil in the second mode, and EPD3 represents the size of the entrance pupil in the third mode. Preferably, 4 < EPD2 < 6 can be satisfied.

[0294] [Equation 53] 3 < ΣCT / n < 7

[0295] [Equation 54] 30 < ΣAd / n< 37

[0296] [Equation 55] 1.55 < ΣNd / n< 1.65

[0297] ΣCT is the sum of the central thicknesses of the first to eighth lenses, and is the sum of the thicknesses of the lenses excluding the reflective member. ΣAd is the sum of the Abbe numbers of the first to eighth lenses, and is the sum of the Abbe numbers of the lenses excluding the reflective member. ΣNd is the sum of the refractive indices of the first to eighth lenses, and is the sum of the refractive indices of the lenses excluding the refractive index of the reflective member. Here, n is the number of lenses excluding the reflective member, and may be 8. In a folded optical system having a reflective member, by satisfying Equations 53-55, the central thicknesses, Abbe numbers, and refractive indices of the lenses can be set to prevent and improve the optical characteristics from deteriorating.

[0298]

[0299] [Equation 56] 0.5 < TD3 / CG4_Max < 1.5

[0300] In mathematical expression 56, CG4_Max is the maximum optical axis spacing between the second and third lens groups that varies depending on the operation mode, and when mathematical expression 56 is satisfied, the maximum optical axis spacing between the second and third lens groups and the optical axis distance (TD3) of the third lens group can be set. Preferably, 1 < TD3 / CG4_Max < 1.3 can be satisfied.

[0301] [Equation 57] 1 < TD4 / CG6_Max < 2

[0302] In mathematical expression 57, CG6_Max is the maximum optical axis spacing between the third and fourth lens groups that varies depending on the operation mode, and in mathematical expression 57, the maximum optical axis spacing between the third and fourth lens groups and the optical axis distance (TD4) of the fourth lens group can be set. Preferably, 1 < TD4 / CG6_Max < 1.5 can be satisfied.

[0303] [Equation 58] 0 < |Max_Distortion| < 3

[0304] In mathematical expression 58, distortion refers to the maximum value or the 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 (190). When the optical system (1000) satisfies mathematical expression 43, the optical system (1000) can improve the distortion characteristics and set conditions for image processing. Preferably, 0 < |Max_Distortion| < 1.5 can be satisfied.

[0305] Table 3 is a table showing the distortion characteristics from the center (Dist F1) to the end (Dist F11) of the first to third embodiments.

[0306] Sensor height Mode 1 Mode 2 Mode 3 Dist(F1) 000 Dist(F2) - 0.01348 0.000299 0.007404 Dist(F3) - 0.0534 0.001153 0.030243 Dist(F4) - 0.11767 0.003523 0.06862 Dist(F5) - 0.2067 0.0062210.121207 Dist(F6) - 0.31956 0.0 058510.186519Dist(F7)-0.454880.0005290.262682Dist(F8)-0.61422-0.009670.348387Dist(F9)- 0.79993-0.0240.443368Dist(F10)-1.03223-0.042780.548158Dist(F11)-1.40048-0.068280.663394

[0307]

[0308] [Equation 59]

[0309]

[0310] In mathematical expression 59, Z may represent Sag, which is the distance from an arbitrary position on an aspherical surface to the vertex of the aspherical surface in the direction of the optical axis. In addition, Y may represent the distance from an arbitrary position on the aspherical surface to the optical axis in the direction perpendicular to the optical axis. In addition, c may represent the curvature of the lens, and K may represent the conic constant. In addition, A, B, C, D, E, and F may represent aspheric constants from the 4th to the 14th order.

[0311]

[0312] The optical system (100) according to the embodiment can satisfy at least one of the above-described mathematical expressions 1 to 57. Accordingly, the optical system (100) and the camera module can have improved optical characteristics. Specifically, since the optical system (100) satisfies at least one or two or more mathematical expressions of the above-described mathematical expressions 1 to 57, it can effectively correct optical characteristic degradation such as chromatic aberration, vignetting, diffraction effect, and deterioration of image quality in the peripheral area caused by movement of the lens group. In addition, the optical system (100) 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.

[0313] Table 4 shows the result values ​​for the mathematical expressions 1 to 28 described above in the optical system (100) of the embodiment. Accordingly, the optical system (100) can have good optical performance and excellent optical characteristics in the center and periphery of the field of view (FOV).

[0314] Equation value 140 < FLG190.0020< L1R1*L1R2238.26031 < CT1 / CT2 < 53.23542 < CT1 / CT3 < 74.90350.5 < CT6 / CT5 < 20.7306L2R1*L2R2 < 0-1593.87FLG4 < 0-14.76787 < TD1 / TTL < 1513.98892 < TTL / EPD3 < 75.957102 < CT_Max / CT_Min < 96.000111< CA_Max / CA_Min <32.464120.1 < ΣCT / TTL < 0.80.357130.5 < TD1 / TD2 < 1.50.896140.5 < TD2 / TD4 < 20.751150 < CG2 / TD2 < 0.20.057162 < TTL / (TD3+TD4) < 74.0251720 < |Ad4 - Ad2| < 5037.0931815 < |Ad8 - Ad6| < 5037.093191.65 < Nd21.680202 < MG1 / MG2 < 64.000210.5 < CA_LG2 / ImgH < 1.51.385224< F1 / FMd1 <157.6572230.5 < |FLG2 / FMd1| < 41.216240.2 < |L4R1 / L4R2| < 31.717251 < L1R1 / L8R2 < 103.697260 < Md12_mLG3 / TTL < 0.50.055270 < Md23_mLG3 / TTL < 0.50.049280.1 < Md12_mLG3 / TD3 < 0.60.389

[0315] Table 5 shows the results for mathematical expressions 29 to 57 described above in the optical system (100) of the embodiments. Accordingly, the optical system (100) can have good optical performance and excellent optical characteristics in the center and periphery of the field of view (FOV).

[0316] 수학식값290.1 ​​< Md23_mLG3 / TD3 < 0.50.347300 < Md23_mLG4 / TTL < 0.30.060310.1 < Md23_mLG4 / TD4 < 10.568321 < Md1 (CG4 / CG6) < 31.524330.2 < Md3 (CG4 / CG6) < 0.90.678342 < Max_mMd13 ≤ 7.55.324351 < CA11 / CA21 < 32.224360.5 < CA21 / CA82 < 1.50.82437Md3_Fno ≤ 4.03.330386 < Md3_BFL < 129.516390.5 < BFL_Min / ImgH < 1.51.19405 < TTL / ImgH < 129.912412 < ImgH3.528423< |FLG1 / FLG2| < 156.296430 < FMd3 / FMd1 < 10.601442 < FMd2 / EPD2 < 62.921451 < FMd1 / EPD1 < 42.405461 < CA_Max / ImgH < 43.277472 < FMd1 / ImgH < 63.332484 FMd3 / ImgH < 105.548491 < FMd3 / Max_mMd13 < 53.6775010 < TTL < 5034.969518 < FOV3 <FOV2 < FOV1 < 45만족523 < EPD1 < EPD2 <EPD3 < 9만족533 < ΣCT / n < 71.565430 < ΣAd / n< 3734.3551.55 < ΣNd / n < 1.651.6560.5 < TD3 / CG4_Max < 1.51.1571 < TD4 / CG6_Max < 21.24

[0317]

[0318] Referring to Fig. 12, the camera module has a first lens (111) of an optical system (100) and a reflective member (P1) coupled to an opening area (101B) inside a first housing (101A), and can be exposed toward an object. A second lens can be coupled to the output side of the reflective member (P1) of the first housing (101A). A second housing (103A) is connected to the inside of the first housing (101A), and refracts light reflected through the reflective member (P1) through the third to eighth lenses of the optical system (110) disclosed above. An image sensor and an optical filter, etc. can be coupled inside the second housing (103A). The height of the upper surface (105) of the second housing (103A) can be lower than the upper surface of the first housing (101A). The above first and second housings (101A, 103A) can be formed integrally.

[0319] A driving member may be coupled inside the second housing (103A) to move the third and fourth lens groups along the optical axis direction. In addition, a driving member for OIS of the reflective member (P1) may be further arranged inside the first housing (101A). The camera module may control the movement of the reflective member (P1) by a control signal. In detail, when shaking occurs in the camera module, information about the shaking, such as the degree of rotation and position change of the sensors, may be detected, and compensation for the shaking may be performed. Accordingly, the camera module according to the embodiment may operate in wide mode, middle mode, and tele mode by the control signal, and when photographing a subject, shaking due to rotation and shaking due to position change may be effectively compensated. Accordingly, the camera module may have improved optical characteristics.

[0320]

[0321] FIG. 13 is a drawing showing a camera module according to an embodiment applied to an electronic device, such as a mobile phone.

[0322] As illustrated in FIG. 13, an electronic device (1000) according to an embodiment of the present invention includes an imaging device (1010), and the imaging device (1010) includes imaging modules (1011, 1012, 1013). For example, one of the imaging modules (1011, 1012, 1013) may perform wide-angle photography, and the other may perform telephoto photography. One of the imaging modules (1011, 1012, 1013) that performs telephoto photography may include at least one optical system (100) of the embodiment and a camera module having the same. Although the imaging device (1010) is illustrated as a rear camera of a smart phone, the imaging device (1010) may also be a front camera of the smart phone. In addition, although the electronic device (1000) is illustrated as a smart phone, the electronic device (1000) may be implemented in other than a smart phone, such as a mobile device such as a PDA, a netbook, a tablet computer, a laptop computer, etc., a wearable device such as a smart watch, a smart band, a smart glasses, etc., a computing device such as a desktop, a server, etc., a home appliance such as a television, a smart television, a refrigerator, etc., a security device such as a door lock, a CCTV, etc., a vehicle such as an autonomous vehicle, a smart vehicle, etc., a camera such as a VR / AR camera, a 360-degree camera, etc., a drone, etc.

[0323] In addition, the portable electronic device (1000) may include a flash module (not shown) and an auto-focus device (not shown). Here, the auto-focus device (not shown) may include a surface-emitting laser element and a light receiving unit as a light-emitting layer. The flash module may include an emitter that emits light therein. The flash module may be operated by the camera operation of the electronic device or by the user's control. The auto-focus device may include an auto-focus function using a laser. The auto-focus device may be mainly used under conditions where the auto-focus function using the image of the camera module is degraded. In addition, although not shown in the drawing, at least one camera module may be further arranged on the front of the portable terminal. At least one of the camera modules in the portable terminal may have a tele-type folded lens assembly as disclosed above.

[0324]

[0325] Fig. 14 is an example of a plan view of a vehicle to which a camera module or optical system according to an embodiment of the invention is applied. Referring to Fig. 24, 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 (31) 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 (31), 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.

[0326] 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.

[0327] At least one information generating unit of these vehicle camera systems may include the optical system and the camera module having the same as described in the above-described embodiments, and may provide or process information acquired through the front, rear, each side, or corner area of ​​the vehicle to a user to enable autonomous driving or to protect the vehicle and objects from surrounding safety. The optical system of the camera module according to the embodiment of the invention may be installed in multiple units in a vehicle to enhance safety regulations, autonomous driving functions, and convenience. In addition, the optical system of the camera module is applied in a vehicle as a component for control such as a lane keeping assistance system (LKAS), a lane departure warning system (LDWS), and a driver monitoring system (DMS). These vehicle camera modules can implement stable optical performance even with changes in ambient temperature and provide modules with competitive prices, thereby ensuring the reliability of vehicle components.

[0328] The features, structures, effects, etc. described in the embodiments above are included in at least one embodiment of the present invention, and are not necessarily limited to just one embodiment. Furthermore, the features, structures, effects, etc. illustrated in each embodiment can be combined or modified and implemented in other embodiments by a person having ordinary skill in the art to which the embodiments pertain. Therefore, the contents related to such combinations and modifications should be interpreted as being included in the scope of the present invention. Although the embodiments have been described above, these are merely examples and do not limit the present invention. Those having ordinary skill in the art to which the present invention pertains will appreciate that various modifications and applications not illustrated above are possible without departing from the essential characteristics of the embodiments. For example, each component specifically shown in the embodiments can be implemented by modification. And the differences related to such modifications and applications should be interpreted as being included in the scope of the present invention defined in the appended claims.

Claims

1. A first lens group having a first lens having positive (+) refractive power and arranged on a first optical axis; Second to fourth lens groups having a plurality of lenses sequentially aligned on a second optical axis different from the first optical axis; and It includes a reflective member arranged between the first lens group and the second lens group, Each of the second to fourth lens groups has at least two lenses, The third lens group has a lens having the thickest central thickness among the central thicknesses of the lenses of the first to fourth lens groups, The object-side surface of the first lens has a convex shape, The effective length of the first lens is greater than the effective lengths of the lenses of the second to fourth lens groups, The first optical axis distance between the first lens and the reflective member is MG1, The second optical axis distance between the above reflective member and the lens adjacent to the above reflective member is MG2, Condition: 2 < MG1 / MG2 < 6 An optical system that satisfies .

2. In paragraph 1, The second lens group includes the second to fourth lenses, The second lens faces the reflective member, The second lens group is an optical system in which the number of lenses having a refractive index of 1.6 or greater is greater than the number of lenses having a refractive index of less than 1.

6.

3. In paragraph 2, The third lens group includes fifth and sixth lenses arranged between the second lens group and the fourth lens group, The above fifth lens is an optical system having the thickest central thickness among the lenses and a convex shape on both sides.

4. In paragraph 3, The fourth lens group includes seventh and eighth lenses arranged between the third lens group and the image sensor, An optical system in which the object-side surface of the above-mentioned eighth lens has a critical point.

5. In paragraph 4, The object-side surface of the above-mentioned 8th lens has a convex shape, An optical system in which the sensor-side surface of the above-mentioned eighth lens has a concave shape.

6. In any one of paragraphs 1 to 5, The second lens group is an optical system in which the number of lenses having negative refractive power is greater than the number of lenses having positive refractive power.

7. In any one of paragraphs 1 to 5, An optical system in which the focal length of the first lens is the largest among the focal lengths of the first to fourth lens groups.

8. In any one of paragraphs 1 to 5, Each of the third and fourth lens groups is an optical system in which the lenses in the second to fourth lens groups move along the second optical axis.

9. In paragraph 8, The focal length of the first lens group is FLG1, The focal length of the second lens group is FLG2, Mathematical formula: │ FLG2│*4 < FLG1 An optical system that satisfies .

10. In any one of paragraphs 1 to 5, The sensor side surface of the above first lens has a concave shape, An optical system in which the object-side surface of the fourth lens group has a concave shape.

11. In paragraph 10, The sensor-side surface of the third lens group has a convex shape, An optical system in which the sensor-side surface of the second lens group has a concave shape.

12. An optical system including first to fourth lens groups; and an image sensor arranged on the sensor side of the fourth lens group, The above optical system is a camera module having claim 8.

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