Optical system and camera module

Abstract

An optical system disclosed in an embodiment of the invention may include: a prism; a first lens bonded to an incident surface of the prism; a second lens bonded to an exit surface of the prism; and a plurality of lenses disposed at a sensor side of the second lens, wherein the first lens has a shape in which an object-side surface is convex on a first optical axis, the second lens and the plurality of lenses are aligned along a second optical axis orthogonal to the first optical axis, and the prism to which the first lens and the second lens are bonded has a focal length of 40 mm or greater.

Description

Optical system and camera module

[0001] The embodiment relates to an optical system for enhanced optical performance and a camera module including the same.

[0002] Camera modules perform the function of capturing objects and saving them as images or videos, and are installed in various applications. In particular, camera modules are manufactured to be ultra-compact, allowing them to be applied not only to portable devices such as smartphones, tablet PCs, and laptops, but also to drones and vehicles, providing a variety of 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. In this case, the camera module can perform an autofocus (AF) function that aligns the focal length of the lens by automatically adjusting the distance between the image sensor and the imaging lens, and can perform a zooming function of zooming up or zooming out to increase or decrease the magnification of distant objects through a zoom lens. Additionally, the camera module employs image stabilization (IS) technology to correct or prevent image shaking caused by camera movement resulting from unstable mounting devices or user 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 on optical systems containing multiple lenses is being conducted 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 characteristics and aberration characteristics. In addition, when multiple lenses are included, the overall length and height may increase due to the thickness, spacing, and size of the multiple lenses, which leads to a problem in that the overall size of the module containing the multiple lenses increases.

[0004] The size of image sensors is increasing to realize high-resolution and high-quality images. However, when the size of the image sensor increases, the Total Track Length (TTL) of the optical system containing multiple lenses also increases, which leads to the problem of increased thickness in cameras, mobile terminals, and other devices containing the said optical system.

[0005] When the above optical system includes multiple lenses, zoom and autofocus (AF) functions can be performed by controlling the position of at least one lens or a lens group including at least one lens. However, when the lens or the lens group performs the above functions, the amount of movement of the lens or the lens group may increase exponentially. Accordingly, the optical system may require a large amount of energy for the movement of the lens or the lens group, and there is a problem that a large volume is required to account for the amount of movement. In addition, there is a problem that aberration characteristics deteriorate due to the movement of the lens or the lens group. Consequently, there is a problem that optical characteristics deteriorate at a specific magnification when performing zoom or AF functions. Therefore, a new optical system capable of solving the aforementioned problems is required.

[0006] The embodiment aims to provide an optical system with improved optical characteristics. The embodiment may provide an optical system and camera module capable of capturing at various magnifications. The embodiment may provide an optical system and camera module having improved aberration characteristics at various magnifications. The embodiment may provide an optical system and camera module having a power prism and a plurality of lenses. At least one or both of the incident surface and the exit surface of the prism may have curvature. At least one lens may be bonded to the incident surface and the exit surface of the prism. The prism may perform an Optical Image Stabilization (OIS) function. The embodiment may provide an optical system and camera module capable of realizing stable performance and high-resolution images by utilizing a prism and a plurality of lenses. The embodiment may provide 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 prism; a first lens attached to the incident surface of the prism; a second lens attached to the exit surface of the prism; and a plurality of lenses disposed on the sensor side of the second lens, wherein the first lens has a convex shape on the object side surface on a first optical axis, and the second lens and the plurality of lenses are aligned with a second optical axis orthogonal to the first optical axis, and the prism to which the first lens and the second lens are attached may have a focal length of 40 mm or more.

[0008] According to an embodiment of the invention, the first lens may have an asymmetric shape and may have a prism side surface having an area less than or equal to the area of ​​the incident surface of the prism. The first lens may be made of a glass material having a refractive index of 1.7 or higher. The absolute value of the difference in radius of curvature between the object side surface of the first lens and the sensor side surface of the second lens may be 10 mm or less. Half of the maximum effective length of the incident surface of the prism is D1, and half of the effective length of the first lens is D2, satisfying the condition: 0.67 ≤ D2 / D1 ≤ 1.

[0009] According to an embodiment of the invention, the second lens may have a concave shape on the second optical axis. The center thickness of the first lens may be thicker than the center thickness of the second lens. The plurality of lenses includes third to eighth lenses, and the center thickness of the seventh lens may be the thickest among the center thicknesses of the first to eighth lenses. With respect to the center of the second lens, the length of the upper region of the exit surface of the prism is D3 and the length of the lower region is D4, and the condition 0.75 ≤ D4 / D3 ≤ 1 may be satisfied.

[0010] According to an embodiment of the invention, at least one of the incident surface of the prism, the exit surface of the prism, or the sensor side surface of the second lens may have a light-blocking layer disposed in an ineffective area. One or more of the plurality of lenses may move along the second optical axis as a group.

[0011] An optical system according to an embodiment of the invention comprises: a prism having an incident surface; an exit-side lens attached to the exit surface of the prism; and a plurality of lenses disposed on the sensor side of the exit-side lens, wherein the incident surface has a convex shape on a first optical axis, and the exit-side lens and the plurality of lenses are aligned with a second optical axis orthogonal to the first optical axis, and the prism to which the exit-side lens is attached may have a focal length of 40 mm or more. The exit-side lens may have a concave sensor-side surface and a prism-side surface with an area less than or equal to the area of ​​the exit surface of the prism. The exit-side lens may have an asymmetrical shape and a prism-side surface with an area less than or equal to the area of ​​the exit surface of the prism.

[0012] According to an embodiment of the invention, with respect to the center of the exit-side lens, the length of the upper region of the exit surface of the prism is D3 and the length of the lower region is D4, satisfying the condition: 0.75 ≤ D4 / D3 ≤ 1. At least one of the incident surface of the prism, the exit surface of the prism, or the sensor-side surface of the exit-side lens may have a light-blocking layer disposed in an ineffective area. At least one or two of the plurality of lenses may move in the direction of the optical axis as a group.

[0013] A camera module according to an embodiment of the invention comprises an optical system including first to fourth lens groups; and an image sensor disposed on the sensor side of the fourth lens group, wherein the optical system is the optical system disclosed above, and within the optical system, the plurality of lenses are lenses of the second to fourth lens groups, and the third and fourth lens groups can move along the second optical axis.

[0014] The optical system and camera module according to the embodiment have various magnifications and can possess 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 the embodiment can correct aberration characteristics of multiple lens groups 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] The optical system and camera module according to the embodiment control the effective focal length (EFL) by moving only some of the lens groups among a plurality of lens groups, and can minimize the movement distance of the moving lens groups. Accordingly, the optical system can reduce the movement distance of the lens groups moving according to the change in operating mode and minimize power consumption required when moving the lens groups. In addition, at least one lens included in the fixed group and the moving group of the optical system may have a non-circular shape.

[0016] An optical system according to an embodiment of the invention can reduce the thickness of the optical system while maintaining optical performance and reduce the overall length of the optical system by reflecting incident light using a prism. Furthermore, it is possible to miniaturize the camera module of a mobile terminal. Additionally, an Optical Image Stabilization (OIS) function can be performed by using a prism that possesses power. At least one or both of the incident surface and the exit surface of the prism may have curvature. At least one lens may be bonded to the incident surface and the exit surface of the prism.

[0017] 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 with the movement of the lens group due to changes in magnification. Therefore, the camera module can have a folded zoom optical system and be provided with a slimmer structure.

[0018] FIG. 1 is a configuration diagram showing an example of a first mode (Wide mode) of a camera module and optical system according to an embodiment of the invention.

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

[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 the aspherical coefficients of the lenses of an optical system according to an embodiment of the invention.

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

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

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

[0025] FIG. 8 is a graph showing the light aberration characteristics of an optical system according to an embodiment in the first mode of FIG. 1.

[0026] FIG. 9 is a graph showing the light aberration characteristics of an optical system according to an embodiment in the second mode of FIG. 2(a).

[0027] FIG. 10 is a graph showing the light aberration characteristics of an optical system according to an embodiment in the third mode of FIG. 2(b).

[0028] FIG. 11 is an exploded perspective view showing a prism according to an embodiment of the invention and lenses bonded to the incident and exit surfaces of the prism.

[0029] FIG. 12 is an exploded perspective view showing the bonding of a lens to the exit surface of a prism according to an embodiment of the invention.

[0030] FIG. 13 is a perspective view of lenses bonded to the incident and exit surfaces of a prism according to an embodiment of the invention.

[0031] Figure 14 is a view from the plane of the prism in which the first and second lenses of Figure 13 are joined.

[0032] Figure 15 is a front view of a prism in which the first and second lenses of Figure 13 are joined.

[0033] FIG. 16 is a drawing showing the light-blocking portion of the first and second lenses joined to the prism of FIG. 13.

[0034] FIG. 17 is a drawing showing the light-blocking portions of the incident and exit surfaces of a prism in which the first and second lenses of FIG. 13 are joined.

[0035] FIG. 18 is a perspective view of a camera module combined with an optical system according to an embodiment of the invention.

[0036] FIG. 19 is a perspective view of a mobile terminal having an optical system and a camera module according to an embodiment of the invention.

[0037] FIG. 20 is a plan view showing an example of a moving body having an optical system and a camera module according to an embodiment of the invention.

[0038] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. However, the technical concept of the present invention is not limited to some of the described embodiments but can be implemented in various different forms, and within the scope of the technical concept of the present invention, one or more of the components among the embodiments may be selectively combined or substituted. Furthermore, terms used in the embodiments of the present invention (including technical and scientific terms) may be interpreted in a meaning generally understood by those skilled in the art to which the present invention belongs, unless explicitly and specifically defined otherwise. Terms used generally, such as those defined in advance, may be interpreted by considering their meaning in the context of the relevant technology. The terms used in the embodiments of the present invention are intended to describe the embodiments and are not intended to limit the present invention.

[0039] In this specification, the singular form may include the plural form unless specifically stated otherwise in the text, and when described as "at least one of A and B and C (or more than one)," it may include one or more of all combinations that can be formed from A, B, and C. Additionally, terms such as first, second, A, B, (a), (b), etc., may be used when describing the components of the embodiments of the present invention. These terms are intended only to distinguish the component from other components and are not to limit the essence, order, or sequence of the component. Furthermore, when it is stated that a component is 'connected,' 'combined,' or 'connected' to another component, this may include not only cases where the component is directly connected, combined, or connected to the other component, but also cases where it is 'connected,' 'combined,' or 'connected' due to another component located between the component and the other component.

[0040] Where described in the specification as being formed or placed "above or below" each component, "above or below" includes not only cases where two components are in direct contact with each other, but also cases where one or more other components are formed or placed between the two components. Furthermore, when expressed as "above or below," it may include the meaning of a downward direction as well as an upward direction relative to a single component.

[0041] In the specification, the statement that the lens surface is convex may mean that the lens surface in the region corresponding to the optical axis or the paraxial region has a convex shape with respect to the optical axis, and the statement that the lens surface is concave may mean that the lens surface in the region corresponding to the optical axis or the paraxial region has a concave shape. Additionally, the "object side surface" may mean the lens surface facing the object side with respect to the optical axis, and the "sensor side surface" may mean the lens surface facing the imaging plane (image sensor) with respect to the optical axis. Additionally, the center thickness of the lens may mean the thickness of the lens in the optical axis direction from the optical axis. Additionally, 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 region of the lens through which incident light passes. Additionally, 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. In addition, the invention has a lens(s) positioned between the prism and the object that are aligned with a first optical axis, and lenses positioned between the prism and the image sensor that can be aligned with an optical axis or a second optical axis.

[0042]

[0043] As shown in FIG. 1, an optical system (100) according to an embodiment of the invention may include a plurality of lens groups. The plurality of lens groups may include at least three lens groups. Each of the plurality of lens groups includes at least one lens. The plurality of lens groups includes first to fourth lens groups (LG1-LG4).

[0044] The optical system (100) may include first to fourth lens groups (LG1-LG4) arranged sequentially along first and second optical axes (OA1, OA2) from an object toward an image sensor (192). For example, the first lens group (LG1) may change direction from the first optical axis (OA1) toward the second optical axis (OA2), and the second to fourth lens groups (LG2-LG4) may be aligned toward the second optical axis (OA2). The first optical axis (OA1) and the second optical axis (OA2) are orthogonal to each other, the first optical axis (OA1) is the optical axis of the lens placed between the prism (110) and the object, and the second optical axis (OA2) is the optical axis of the lenses placed between the prism (110) and the image sensor (192). 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 (192) can be defined as the optical axis or the second optical axis (OA2).

[0045] The second lens group (LG2) is positioned between the first lens group (LG1) and the third lens group (LG3), and the third lens group (LG3) may be positioned 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 collect light rays, the third lens group (LG3) is an element that changes the zoom magnification of the optical system, i.e., the focal length, and the fourth lens group (LG4) is an element that adjusts the focal position of the imaging plane. That is, the fourth lens group (LG4) can perform the role of controlling the Chief Ray Angle (CRA).

[0046]

[0047] The optical system (100) may include n lenses and prisms (110), the nth lens may be the last lens, and the (n-1)th lens may be the lens closest to the last lens. n is an integer greater than or equal to 7, for example, 7 to 9. Within the optical system (100), the lenses may be defined as lens parts.

[0048] Among the plurality of lens groups mentioned above, at least two lens groups are fixed lens groups with fixed positions, and at least two lens groups may be variable lens groups with variable positions. 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 a third and fourth lens group (LG3, LG4) positioned between the second lens group (LG2) and the image sensor (192) may be variable lens groups. Here, the variable lens groups may be moved in the direction of the optical axis (OA2) or returned to their original positions. By the variable lens groups, the optical system (100) may provide a continuous zoom optical system having a wide mode, a middle mode, and a tele mode. Additionally, the first lens group (LG1) may be equipped with a prism (110), and the prism (110) may provide a folded zoom optical system. The moving distance of the above-mentioned moving lens groups can be set to a maximum of 7.5 mm or less to reduce the power consumption of the driving member. In addition, when in tele mode, the optical axis spacing (CG6) between the third and fourth lens groups (LG3, LG4) can be set to 1 mm or more, for example, exceeding 1 mm, thereby reducing the moving distance of the fourth lens group (LG4) and providing a high-magnification optical system.

[0049]

[0050] The number of lenses in each of the first lens group (LG1) and the second lens group (LG2) may be the same. The number of lenses in the first lens group (LG1) is the number of lenses excluding prisms. The number of lenses in each of the first lens group (LG1) and the second lens group (LG2) may be three or fewer, for example, two. The number of lenses in each of the second lens group (LG2) and the third lens group (LG3) may be the same or different, for example, three or fewer. For example, the number of lenses in the third lens group (LG3) may be the same as the number of lenses in the second lens group (LG2). The number of lenses in the fourth lens group (LG4) may be the same or different from the number of lenses in the second lens group (LG2) or the third lens group (LG3). The number of lenses in each of the second lens group (LG2) and the third lens group (LG3) may be three or fewer, for example, two. As another example, the number of lenses in the fourth lens group (LG4) may be one. By stacking these lenses, an optical system for wide mode, middle mode, and tele mode can be provided, and a bright optical system with an F-number in the range of 2.0 to 4.0 can also be provided depending on the operating mode.

[0051] When in zoom magnification or focusing mode, the maximum travel 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 5 mm. If the maximum travel distance of the third and fourth lens groups (LG3, LG4) is greater than the above range, the length of the camera module becomes longer, and it may be difficult to secure optical performance. In addition, if it is smaller than the above range, the zoom magnification may be reduced.

[0052]

[0053] At least one or all of the lenses of the first lens group (LG1) may be made of glass. The lenses of the first lens group (LG1) and the prism (110) may be made of glass. As another example, the first lens (111) placed on the object side of the prism (110) may be made of glass, and the second lens (112) placed on the sensor side of the prism (110) may be made of glass or plastic. At least one of the lenses of the first lens group (LG1) may have a refractive index of 1.7 or higher. For example, the first lens (111) closest to the object may have a refractive index of 1.7 or higher and be made of glass. If both the incident lens and the exit lens of the first lens group (LG1) are made of glass, the diameter of the beam emitted through the prism (110) can be reduced. In the specification, the refractive index is the refractive index at the d-line (e.g., 587.6 nm).

[0054] At least one or all of the lenses in the second to fourth lens groups (LG2-LG4) may be made of plastic, for example, plastic. Additionally, the lenses within the movable lens groups (LG3, LG4) may be made of plastic to prevent an increase in the power consumption of the driving member. As another example, each of the movable lens groups (LG3, LG4) may include a plastic lens and a glass lens. As another example, among the lenses of the first fixed lens group (LG1), the lens closest to the object may be made of glass. As another example, the last lens in the fourth lens group (LG4) closest to the image sensor (192) 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 above-mentioned aspherical shape can prevent spherical aberration within the optical system (100), and since no aberration occurs even when the effective diameter is increased, it is possible to miniaturize and lighten the camera module. The above-mentioned aspherical lens may be made of a glass mold or plastic material.

[0055] The object-side surface of the second lens group (LG2) is the fifth surface (S5), and the fifth surface (S5) may have a convex shape toward the object on the optical axis (OA2). That is, the radius of curvature of the fifth surface (S5) may have a positive value on the optical axis (OA2). Since the radius of curvature of the fifth surface (S5) has a positive value, the beam size can be reduced.

[0056]

[0057] The power of the first lens group (LG1) may have an opposite sign to 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 an opposite sign to the power 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. Among the lenses in the optical system (100), the number of lenses having negative power may be greater than the number of lenses having positive power.

[0058] When each of the first, third, and fourth lens groups (LG1, LG3, LG4) has two or more lenses, they may include a lens with negative power and a lens with positive power. Accordingly, the lens optical system can correct optical aberrations and improve image quality by mixing a lens with positive power and a lens with negative power. The power is the reciprocal of the focal length value.

[0059] 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 three times, for example, in the 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) can disperse the 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 smaller than the focal length of the first lens group (LG1) and larger than the focal length of the third lens group (LG3).

[0060] The focal length of the first lens group (LG1) is FLG1, and the focal length of the second lens group (LG2) is FLG2, satisfying the condition │FLG2│ < FLG1. The focal length of the third lens group (LG3) is FLG3, and the focal length of the fourth lens group (LG4) is FLG4, satisfying the condition FLG3 < │FLG4│. The focal length of the first lens group (LG1), which has a fixed position, may be greater than the sum of the absolute values ​​of the focal lengths of the third and fourth lens groups (LG3, LG4), which 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) comprises a prism (110), a first lens (111) on the object side of the prism (110), and a second lens (112) on the sensor side of the prism (110). 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 80 mm to 250 mm. The first lens group (LG1) performs an OIS function and can suppress a decrease in resolution due to the focal length.

[0061] The sensor-side second surface (S2) of the first lens (111) is attached to the incident surface of the prism (110), and the object-side third surface (S3) of the second lens (112) is attached to the exit surface of the prism (110). The prism (110) includes a reflective surface (RS0) that reflects light incident from the incident surface to the exit surface. The reflective surface (RS0) may be inclined in a range of 30 to 60 degrees or 45 degrees with respect to the second optical axis (OA2). The second surface (S2) of the first lens (111) and the incident surface of the prism (110) have a planar shape and are attached to each other with an adhesive. The third surface (S3) of the second lens (112) and the exit surface of the prism (110) have a planar shape and are attached to each other with an adhesive.

[0062]

[0063] The object-side or 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 (OA1). The sensor-side or exit-side surface of the first lens group (LG1) is the fourth surface (S4), and the fourth surface (S4) may have a concave shape on the optical axis (OA2). Since the first surface (S1) has a convex shape, the incident efficiency of light can be improved. In addition, since the fourth surface (S4) of the second lens (112) on the exit side of the prism (110) has a concave shape, the increase in the effective length or effective diameter of the second lens group (LG2) can be suppressed. The absolute difference in the radius of curvature on the optical axis between the first surface (S1) and the fourth surface (S4) may be 10mm or less. The radius of curvature on the first optical axis (OA1) of the first surface (S1) is R1, and the radius of curvature on the optical axis (OA2) of the fourth surface (S4) is R4, and the difference between the radii of curvature may satisfy the following conditions.

[0064] Condition: -10mm ≤ |R1| -|R4| ≤ 10mm

[0065]

[0066] The effective length of the first surface (S1) on the object side of the first lens group (LG1) may be greater than the effective length of the fourth surface (S4) on the sensor side. The effective lengths of the first and fourth surfaces (S1, S4) may be diagonal lengths or maximum lengths. If the effective length of the first surface (S1) is CA11 and the effective length of the fourth surface (S4) is CA22, the following conditions may be satisfied.

[0067] Condition: 1 < CA11 / CA22 < 2.3

[0068] If the effective length of the first and fourth surfaces (S1, S4) is greater than the above range, the thickness of the prism (110) increases and the light path increases, which may result in a decrease in optical performance.

[0069]

[0070] Among the lenses of the first to fourth lens groups (LG1-LG4), the lens with the highest refractive index may be the first lens (111). The first lens (111) can refract the path of incident light into various paths, thereby improving resolution. Among the lenses of the first to fourth lens groups (LG1-LG4), the largest value of the Abbe number may be 45 or higher, and lenses with large Abbe numbers can reduce chromatic aberration. Additionally, the lens closest to the image sensor (192) may have an Abbe number of 45 or higher. When the Abbe numbers of the two lenses within the first lens group (LG1) are Ad1 and Ad2, the condition │Ad1-Ad2│ < 20 may be satisfied, for example, │Ad1-Ad2│ < 10, and if the above condition is satisfied, the change in chromatic aberration within the first lens group (LG1) can be minimized.

[0071] Among the lenses of the first to fourth lens groups (LG1-LG4), the lens with the largest center thickness can be placed within the fourth lens group (LG4). Accordingly, changes in the light path caused by the lenses of the fourth lens group (LG4) can be reduced.

[0072] If 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.

[0073] Condition 1: 10 < ΣNd < 15 Condition 2: 240 < ΣAd < 330

[0074] Aberrations can be controlled by adjusting the refractive index and Abbe number of the lenses in the optical system (100). Chromatic dispersion can be reduced by the lens having the maximum Abbe number, and chromatic dispersion of incident light can be increased by the lens material having a refractive index of 1.7 or higher.

[0075] Each of the lenses of the optical system (100) may include an effective region and an ineffective region. The effective region may be a region through which light incident on each of the lenses passes. That is, the effective region may be defined as an effective region or CA (Clear aperture) where the incident light is refracted to realize optical characteristics. The ineffective region may be placed around the periphery of the effective region. The ineffective region may be a region where effective light is not incident from the plurality of lenses. That is, the ineffective region may be a region unrelated to the optical characteristics. Additionally, the edge of the ineffective region may be a region fixed to a lens barrel (not shown), etc., that accommodates the lens.

[0076] The average of the effective lengths of the object-side and sensor-side surfaces of each lens in the lens section can be provided in a range of 5mm or more, for example, from 5mm to 7mm. Here, the average of the effective lengths may be the average of the effective lengths of the object-side and sensor-side surfaces of each lens or the average of the maximum effective lengths. The maximum effective length of the object-side surface (S1) of the first lens (111) may be provided to be 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.

[0077]

[0078] At least one or two of the lenses in the optical system (100) 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) that are orthogonal to each other. In addition, at least one or two of the lenses in the second lens (112) and the second, third, and fourth lens groups (LG2, LG3, LG4) may have different effective lengths in the first and second directions (X, Y). Here, the shape of the object-side or sensor-side of the lens having different effective lengths in two orthogonal directions may be non-circular. When the effective lengths in the second direction (Y) and the third direction (Z) of the first lens (111) are different, the effective length in the second direction (Y) of the first lens (111) may be longer than the effective length in the third direction (Z). Accordingly, the total length (ZL1) of the lens optical system can be reduced. Among the lenses of the second lens (112) and the second, third, and fourth lens groups (LG2, LG3, LG4), the effective length of the lens with a different effective length may have an effective length in the second direction (Y) that is smaller than the effective length in the first direction (X). Accordingly, the thickness of the lens optical system in the second direction (Y) can be reduced, and an increase in the thickness of the camera module and the mobile terminal can be prevented.

[0079]

[0080] In the optical system (100), the Total Track Length (TTL) may be greater than 5 times ImgH, preferably satisfying the conditions 5 < TTL / ImgH < 15 or 7 < TTL / ImgH < 11. The TTL is the total track length measured along the optical path from a reference point on the object side surface (S1) of the first lens (111) to the surface of the image sensor (192). The TTL is the sum of the distance (TTL2) in the direction of the first optical axis (OA1) from the center of the object side surface (S1) of the first lens (111) to the reflective surface (RS0) of the prism (110) and the distance (TTL1) in the direction of the optical axis (OA2) from the reflective surface (RS0) of the prism (110) to the surface of the image sensor (192). The optical axis distance of the prism (110) is the sum of the optical axis distance (RT1) from the center of the reflective surface (RS0) to the incident surface and the optical axis distance (RT2) from the center of the reflective surface (RS0) to the exit surface. The optical axis distance of the prism (110) is the sum of the thickness at the first optical axis (OA1) and the thickness at the optical axis (OA2). The thickness (H0) of the first lens group (LG1) is the vertical distance from the bottom of the exit surface of the prism (110) to the center of the first object-side surface (S1) of the first lens (111). The thickness (H0) of the first lens group (LG1) represents the thickness of the optical system (100). ImgH is the length from the center of the image sensor (192) to the diagonal end, or half the diagonal length of the image sensor (192). Here, ImgH, TTL, TTL1, and TTL2 can satisfy the following conditions.

[0081] Condition 1: TTL1 < TTL2 Condition 2: 0.1 < TTL1 / TTL < 0.2

[0082] Condition 3: 2mm < ImgH < TTL1

[0083] 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 zoom optical system for a mobile terminal. Accordingly, the optical system (100) can provide a high-resolution and high-magnification zoom optical system. The total length (ZL1) of the optical system (100) is the maximum length in the third direction (Z), and is the length in the optical axis direction from one end of the first lens (111) or one end of the prism (110) to the image sensor (192).

[0084]

[0085] The number of lenses having an effective length greater than the maximum effective length of the image sensor (192) within the lens section is less than 30%, for example, in the range of 10% to 30%. The effective length of the lens closest to the object side within the lens section may be greater than the effective length of the lens closest to the image sensor (192). Additionally, the effective length of the lens placed on the object side of the aperture (ST) (e.g., 114) and the lens placed on the sensor side of the aperture (ST) (e.g., 115) may be smaller than the diagonal length of the image sensor (192). Accordingly, the brightness of the optical system can be controlled. By controlling the effective aperture size of each of the lenses, the optical system (100) can control the incident light to compensate for the degradation of optical characteristics due to resolution and temperature changes, and can improve chromatic aberration control characteristics. Here, the effective length of each lens is the average of the effective lengths in two different directions.

[0086]

[0087] The center gap (CG2) between the first lens group (LG1) and the second lens group (LG2) may be greater than the center gap between lenses within the second lens group (LG2), the center gap between lenses within the third lens group (LG3), and the center gap between lenses within the fourth lens group (LG4). The center gap (CG2) between the first lens group (LG1) and the second lens group (LG2) may be greater than the minimum gap between the second and third lens groups (LG2, LG3), which varies according to the operating mode, and smaller than the maximum gap. The center gap (CG2) between the first lens group (LG1) and the second lens group (LG2) may be smaller than the minimum gap between the third and fourth lens groups (LG3, LG4). The center gap (CG2) between the first lens group (LG1) and the second lens group (LG2) may be smaller than the center thickness of the first lens (111) and larger than the center thickness of the second lens (112). Since the center gap (CG2) between the first lens group (LG1) and the second lens group (LG2) is provided as 0.5 mm or more, for example, 0.5 mm to 1.5 mm, light loss can be reduced in the area between the first and second lens groups (LG1, LG2). On the optical axis (OA2), the sensor-side surface (S4) of the first lens group (LG1) may be concave, and the object-side surface of the second lens group (LG2) may have a convex shape.

[0088]

[0089] The optical system (100) or camera module may include an image sensor (192). The image sensor (192) may detect light and convert it into an electrical signal. The image sensor (192) may detect light that has passed through the lens group (LG1-LG4) sequentially. The image sensor (192) may include a device 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 (190). The optical filter (190) may be placed between the fourth lens group (LG4) and the image sensor (192). The optical filter (190) may be placed between the lens closest to the sensor side among the lenses of the lens unit and the image sensor (192). For example, the optical system may be positioned between the last lens and the image sensor (192). A cover glass (not shown) is positioned between the optical filter (190) and the image sensor (192), and can protect the top of the image sensor (192) and prevent a decrease in the reliability of the image sensor (192). The cover glass may be removed.

[0090] The optical filter (190) may include an infrared filter or an infrared cut-off filter (IR cut-off). The optical filter (190) may pass light of a set wavelength band and filter light of a different wavelength band. If the optical filter (190) includes an infrared filter, it may block radiant heat emitted from external light from being transmitted to the image sensor (192). Additionally, the optical filter (190) may transmit visible light and reflect infrared light.

[0091] The optical system (100) according to the 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 positioned between any two lenses within the lens assembly. In the case of lenses positioned between an object and the aperture (ST), the effective diameter of the lens tends to decrease as it moves from the object side toward the aperture (ST). The aperture (ST) may be positioned at a set location. The aperture (ST) may be positioned around the object-side or sensor-side surface of any one of the lenses of the third lens group (LG3). For example, the aperture (ST) may be positioned around the object-side surface of the third lens group (LG3). As another example, the aperture (ST) may be positioned around the sensor-side surface of the second lens group (LG2). The aperture (ST) may function as an aperture if a coated portion on the non-effective surface area of ​​at least one of the lenses of the second and third lens groups (LG2, LG3). Specifically, the object-side or sensor-side of one selected lens among the lenses of the optical system (100) may function as an aperture that controls the amount of light. The optical axis distance between the aperture (ST) and the image sensor (192) is SD, and the value of SD may vary depending on the operating mode, such as wide mode, middle mode, or tele mode.

[0092] Since the fourth lens group (LG4) is moved, the optical axis distance between the fourth lens group (LG4) and the image sensor (192) is BFL, and the value of BFL may vary depending on the operating mode, such as wide mode, middle mode, or tele mode. BFL is the distance in the optical axis (OA2) direction between the center of the last lens and the image sensor (192). BFL is the distance in the optical axis (OA2) direction from the vertex or reference point on the sensor side of the last lens to the light-receiving surface of the image sensor.

[0093]

[0094] The camera module (100) can control the movement of the prism (110) by means of a control signal. Specifically, if shaking occurs in the camera module (100), information regarding the shaking, such as the degree of rotation and position change of the sensors, can be detected, and correction for the shaking can be performed. In addition, the camera module (100) can control the movement of the moving lens group by means of a driving signal, detect position changes, and vary the focal length. Accordingly, when shooting a subject located at infinity or near distance using the camera module (100), shaking caused by rotation and position change can be effectively corrected. The camera module (100) according to the embodiment can effectively correct shaking caused by rotation and shaking caused by position change when shooting a subject located at infinity or near distance. Therefore, the camera module (100) can have improved optical characteristics.

[0095]

[0096] 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, the object-side lens of the prism (110) can be defined as the first lens, and the sensor-side lens of the prism (110) can be defined as the second to eighth lenses stacked sequentially. The center thickness of the first to eighth lenses can be defined as CT1 to CT8, the edge thickness of the first to eighth lenses can be defined as ET1 to ET8, and the focal length of the first to eighth lenses can be defined as F1 to F8. The refractive index of the first to eighth lenses can be defined as Nd1 to Nd8. The Abbe number of the first to eighth lenses can be defined as Ad1 to Ad8.

[0097] In addition, the center gap between adjacent second and third lenses is CG2, the center gap between third and fourth lenses is CG3, the center gap between fourth and fifth lenses is CG4, the center gap between fifth and sixth lenses is CG5, the center gap between sixth and seventh lenses is CG6, the center gap between seventh and eighth lenses is CG7, and the center gap between the eighth lens and the image sensor can be defined as BFL.

[0098] Additionally, the effective lengths of the object side and sensor side of the first lens are defined as CA11 and CA12; the effective lengths of the object side and sensor side of the second lens are defined as CA21 and CA22; the effective lengths of the object side and sensor side of the third lens are defined as CA31 and CA32; the effective lengths of the object side and sensor side of the fourth lens are defined as CA41 and CA42; the effective lengths of the object side and sensor side of the fifth lens are defined as CA51 and CA52; the effective lengths of the object side and sensor side of the sixth lens are defined as CA61 and CA62; the effective lengths of the object side and sensor side of the seventh lens are defined as CA71 and CA72; and the effective lengths of the object side and sensor side of the eighth lens are defined as CA81 and CA82. Furthermore, the average of the effective lengths of the object side and sensor side of each of the first to eighth lenses can be defined as CA1 to CA8.

[0099]

[0100] An optical system and camera module of an embodiment will be described with reference to FIGS. 1 to 10. Referring to FIGS. 1 to 5, the optical system (100) according to the embodiment includes first to fourth lens groups (LG1, LG2, LG3, LG4). The first and second lens groups (LG1, LG2) positioned between an object and the third lens group (LG3) have fixed positions, while the third and fourth lens groups (LG3, LG4) positioned between the second lens group (LG2) and the image sensor (192) have variable positions depending on the operation mode. The operation 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 the effective focal length.

[0101] The first lens group (LG1) refracts incident light toward the second lens group (LG2), and the prism (110) reflects the incident light; the second lens group (LG2) refracts the light incident through the first lens group (LG1); the third lens group (LG3) moves along the optical axis (OA2) to change the zoom magnification (focal length); and the fourth lens group (LG4) moves along the optical axis (OA2) to adjust the focal position on the upper surface of the image sensor (192). The focal lengths of the first to fourth lens groups (LG1-LG4) are defined as FLG1, FLG2, FLG3, and FLG4, and may satisfy the following conditions. In the specification, * indicates multiplication.

[0102] Condition 1: │FLG2│*4 < FLG1

[0103] Condition 2: FLG3 < │FLG2│ < FLG3*4

[0104] Condition 3: │FLG4│ < │FLG2│

[0105] Condition 1 can preferably satisfy │FLG2│*6 < FLG1. Also, F*10 < FLG1 can be satisfied, where F is the effective focal length of the optical system.

[0106]

[0107] The optical system (100) may include a first lens (111), a prism (110), and second to eighth lenses (112-118). The first lens group (LG1) includes a first lens (111), a prism (110), and a second lens (112). The second lens group (LG2) includes a third lens and a fourth lens (113, 114). The third lens group (LG3) includes fifth and sixth lenses (115, 116). The fourth lens group (LG4) includes seventh and eighth lenses (117, 118). The first lens (111) is positioned on the incident surface of the prism (110), and the second lens (112) is positioned on the exit surface of the prism (110). The first lens (111) is bonded to the incident surface of the prism (110), and the second lens (112) is bonded to the exit surface of the prism (110). Here, the bonding is in an area where the gap between the prism (110) and the first lens (111) or the gap between the prism (110) and the second lens (112) is 0.01 mm or less. The prism (110) is positioned between the first lens (111) and the second lens (112), and reflects light incident through the first lens (111) to the second lens (112).

[0108]

[0109] The first and third lenses (111, 113) can correct aberrations by having refractive powers of opposite signs (+, -), and the fifth and sixth lenses (115, 116) can correct aberrations by having refractive powers of opposite signs (+, -). The seventh and eighth lenses (117, 118) can correct aberrations by having refractive powers of opposite signs (+, -). The optical axis distance (BFL) between the eighth lens (118) and the image sensor (192) can be varied according to the operating mode and can provide a space for the optical filter (190) to be installed. The first lens (111) can have a positive (+) or negative (-) refractive power on the first optical axis (OA1), for example, it can have a positive refractive power. The first lens (111) may include plastic or glass material, for example, it may be glass 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 planar shape. Alternatively, the first surface (S1) may have a concave shape. The first surface (S1) may be spherical.

[0110] 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) in the first and third directions (X, Z) may be greater than the average of the effective lengths of the object-side and sensor-side surfaces of the second to eighth lenses (112-118). Accordingly, the first lens (111) can improve optical aberrations or control incident light rays. The first surface (S1) may be provided without a threshold point from the optical axis to the end of the effective area. The maximum effective length of the third direction (Z) of the second sensor-side surface (S2) of the first lens (111) 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).

[0111] The sensor-side second surface (S2) of the first lens (111) may be flat. Here, the length of the third direction (Z) of the second surface (S2) of the first lens (111) may be equal to or greater than the length of the third direction (Z) of the incident surface (RS1, see FIG. 3) of the prism (110).

[0112]

[0113] The second lens (112) may have a positive (+) or negative (-) refractive power on the optical axis (OA2), for example, it may have a negative refractive power. The second lens (112) may include a plastic or glass material, for example, it may be a glass 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 on the optical axis, the third surface (S3) may have a planar shape and the fourth surface (S4) may have a concave shape. Alternatively, the fourth surface (S4) may have a convex shape. The fourth surface (S4) of the second lens (112) may be spherical. The length (Y) of the second direction of the third surface (S3) of the second lens (112) may be equal to or smaller than the length of the second direction (Y) of the exit surface (RS2, see FIG. 3) of the prism (110).

[0114]

[0115] The prism (110) is P1 in the lens data of FIG. 3, the incident plane is RS1, and the exit plane is RS2, and the first optical axis (OA1) and the optical axis (OA2) intersect on the reflective plane (RS0) of FIG. 1. The prism (110) may be provided as a triangular prism. The prism (110) may be provided as a glass material. The refractive index of the prism (110) may be higher than the refractive index of the second lens (112). Within the prism (110), the incident plane (RS1) may be the object side surface, and the exit plane (RS2) may be the sensor side surface. The reflective plane (RS0) of the prism (110) reflects light incident on the incident plane (RS1) to the exit plane (RS2) and may be inclined at an angle of 45 degrees with respect to the first optical axis (OA1). The incident surface (RS1) may have a polygonal shape, for example, a square shape. The exit surface (RS2) may have a polygonal shape, for example, a square shape. The prism (110) may have the highest refractive index within the lens optical system. The refractive index of the prism (110) may be higher than the refractive indices of the lenses of the second to fourth lens groups (LG2, LG3, LG4).

[0116]

[0117] The third lens (113) may have the same sign as the sign of the refractive power of the second lens (112) on the optical axis (OA2). That is, the third lens (113) may have a negative refractive power. The third lens (113) may include a plastic or glass material, 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. On the optical axis (OA2), the fifth surface (S5) may have a convex shape, and the sixth surface (S6) may have a convex shape. The third lens (113) may have a convex shape on both sides. Alternatively, the fifth surface (S5) may have a convex shape, and the sixth surface (S6) may have a concave shape. Alternatively, the fifth surface (S5) may have a concave shape, and the sixth surface (S6) may have a convex shape. At least one or all of the fifth surface (S5) and the sixth surface (S6) of the third lens (113) may be aspherical. The aspherical coefficients and conic constants (K) of the 4th to 20th order (AI) of the fifth and sixth surfaces (S5, S6) can be represented as L3S5 and L3S6 of FIG. 4. The fifth surface (S5) and the sixth surface (S6) may be provided without a critical point from the optical axis to the end of the effective area. Hereinafter, the critical point may be defined as an inflection point.

[0118] The second and third lenses (112, 113) have power opposite to that of the first lens (111), so they can compensate for chromatic aberration occurring in the first lens (111). The refractive index of the first lens (111) is positioned to be greater than that of the second and third lenses (112, 113), thereby dispersing the incident light. Accordingly, since the first lens group (LG1) controls the dispersion of light provided to the second lens group (LG2), the increase in the lens size of the second lens group (LG2) can be suppressed.

[0119]

[0120] The fourth lens (114) may have a negative (-) refractive power on the optical axis (OA2). The fourth lens (114) may be made of plastic or glass material, for example, plastic material, and may have a refractive index of less than 1.65. The fourth lens (114) includes a seventh surface (S7) on the object side and an eighth surface (S8) on the sensor side, and on the optical axis (OA2), the seventh surface (S7) may have a concave shape and the eighth surface (S8) may have a convex shape. That is, the fourth lens (114) may have a meniscus shape that is convex toward the sensor on the optical axis (OA2). Alternatively, the seventh surface (S7) may be convex on the optical axis (OA2) and the eighth surface (S8) may be concave on the optical axis (OA2).

[0121] At least one or all of the seventh surface (S7) and the eighth surface (S8) of the fourth lens (114) may be aspherical. The conic constant (K) of the seventh and eighth surfaces (S7, S8) and the aspherical coefficients from the 4th to the 20th order (AI) may be represented as L4S7 and L4S8 in FIG. 4. The seventh surface (S7) and the eighth surface (S8) may be provided without a critical point from the optical axis to the end of the effective area.

[0122]

[0123] The fifth lens (115) may have a positive (+) or negative (-) refractive power on the optical axis (OA2). The fifth lens (115) may have a positive refractive power. The fifth lens (115) may have a power on the optical axis (OA2) with a sign opposite to the sign of the power of the fourth lens (114). The fifth lens (115) may include a plastic or glass material, for example, a plastic material. The fifth lens (115) may include an object-side ninth surface (S9) and a sensor-side tenth surface (S10). On the optical axis (OA2), the ninth surface (S9) may have a convex shape, 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 meniscus shape that is convex toward an object or sensor.

[0124] At least one or all of the ninth surface (S9) and the tenth surface (S10) of the fifth lens (115) may be aspherical. The conic constant (K) of the ninth and tenth surfaces (S9, S10) and the aspherical coefficients from the fourth to the twentieth order (AI) may be represented as L5S9 and L5S10 of FIG. 4. The ninth surface (S9) and the tenth surface (S10) of the fifth lens (115) may be provided without a critical point from the optical axis to the end of the effective area.

[0125] 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) can be reduced by the concave eighth surface (S8) of the fourth lens (114) and the convex ninth surface (S9) of the fifth lens (115).

[0126]

[0127] The sixth lens (116) may have a positive (+) or negative (-) refractive power on the optical axis (OA2), for example, it may have a negative refractive power. The sixth lens (116) may include a plastic or glass material, for example, it may be a plastic material. The sixth lens (116) may include an object-side eleventh surface (S11) and a sensor-side twelfth surface (S12). On the optical axis (OA2), the eleventh surface (S11) may have a concave shape, 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 side on the optical axis (OA2). Alternatively, the sixth lens (116) may have a convex shape on both sides. Alternatively, the sixth lens (116) may have a concave shape on both sides. Alternatively, the sixth lens (116) may have a meniscus shape that is convex toward the object.

[0128] At least one or both of the 11th surface (S11) and the 12th surface (S12) of the 6th lens (116) may be aspherical. The aspherical coefficients and conic constants (K) from the 4th to the 20th order (AI) of the 11th and 12th surfaces (S11, S12) may be represented as L6S11 and L6S12 of FIG. 4. The 11th surface (S11) and the 12th surface (S12) may be provided without a critical point from the optical axis to the end of the effective area. The center thickness (CT5) of the 5th lens (115) may be thicker than the center thickness (CT6) of the 6th lens (116). The center thickness (CT6) of the 6th lens (116) may be greater than the center thickness of the 1st to 4th lenses (111-114).

[0129] 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 Abbe numbers between the third lens (113) and the fifth lens (115) may be greater than 20. Accordingly, the third lens group (LG3) can minimize changes in chromatic aberration caused by changes in position according to changes in the operating mode. The Abbe number (Ad4) of the fourth lens (114) may be greater than 20 than the Abbe number of the third lens (113). The fifth lens (115) and the sixth lens (116) have refractive powers of opposite signs, and if the difference in Abbe numbers is set to be greater than 20, chromatic aberration can be controlled. Accordingly, the third lens group (LG3) can perform an achromatic function while minimizing changes in chromatic aberration caused by changes in position according to changes in the mode.

[0130]

[0131] The seventh lens (117) may have a positive (+) or negative (-) refractive power on the optical axis (OA2), and may have a 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, 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. On the optical axis (OA2), the 13th surface (S13) may have a concave shape, and the 14th surface (S14) may have a convex shape. That is, the seventh lens (117) may have a meniscus shape that is convex toward the sensor on the optical axis (OA2). As another example, the 13th surface (S13) may have a convex shape and the 14th surface (S14) may have a concave shape. Alternatively, the 13th surface (S13) may have a 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 concave shape. At least one or all of the 13th surface (S13) and the 14th surface (S14) of the 7th lens (117) may be aspherical. The aspherical coefficients and conic constants (K) from the 4th to the 20th order (AI) of the 13th and 14th surfaces (S13, S14) can be represented as L7S13 and L7S14 in FIG. 4. The above 13th surface (S13) and the above 14th surface (S14) can be provided without a threshold point from the optical axis to the end of the effective area.

[0132]

[0133] The eighth lens (118) may have a positive or negative refractive power on the optical axis (OA2), for example, it may have a negative refractive power. The eighth lens (118) may include a plastic or glass material, for example, it may be a plastic material. The eighth lens (118) may include a 15th surface (S15) on the object side and a 16th surface (S16) on the sensor side. On the optical axis (OA2), the 15th surface (S15) may have a convex shape, and the 16th surface (S16) may have a concave shape. That is, the eighth lens (118) may have a meniscus shape that is convex toward the object or prism (110) on the optical axis (OA2). Alternatively, the 15th surface (S15) may have a concave shape, and the 16th surface (S16) may have a convex shape.

[0134] At least one or all of the 15th surface (S15) and the 16th surface (S16) of the 8th lens (118) may be aspherical. The 4th to 20th aspherical coefficients and conic constants (K) of the 15th and 16th surfaces (S15, S16) may be represented as L8S15 and L8S16 of FIG. 4. At least one of the 15th surface (S15) and the 16th surface (S16) may have a critical point within the region from the optical axis to the end of the effective region. The critical point of the 15th surface (S15) may be positioned at least 24% of the effective radius from the optical axis (OA2), for example, in the range of 24% to 44%, relative to the optical axis (OA2). The critical point of the 16th surface (S16) can be positioned at least 71% of the effective radius from the optical axis (OA2), for example, in the range of 71% to 91%, based on the optical axis (OA2). Since the 15th surface (S15) has a critical point, light can be refracted from the area surrounding the critical point to different areas of the 16th surface (S16). Also, since the 16th surface (S16) has a critical point, incident light can be refracted to the entire area of ​​the image sensor (192). The critical point is the point where the trend of the Sag (Sagitta) value changes. That is, the critical point is the point on the lens surface where the Sag value increases and then decreases, or where the Sag value decreases and then increases. The above Sag value is the optical axis distance between the straight line perpendicular to the center of each lens surface and the lens surface; the Sag value has a positive value for positions located closer to the sensor than the center of each lens surface, and a negative value for positions located closer to the object than the center of each lens surface.

[0135]

[0136] The center thickness (CT7) of the seventh lens (117) may be the thickest among the center thicknesses of the first to eighth lenses (111-118). The center thicknesses (CT1-CT8) of the first to eighth lenses (111-118) may satisfy the following conditions.

[0137] Condition 1: CT2 < CT1 Condition 2: CT3 < CT1 < (CT2+CT3+CT4)

[0138] Condition 3: CT4*3 < CT5 Condition 4: CT6 < CT5 < CT7

[0139] Condition 5: CT4 < CT8 < CT1 < CT6

[0140]

[0141] Since the 16th surface (S16) of the 8th lens (118) is provided in a concave shape, incident light can be refracted toward the entire area of ​​the image sensor (192). The effective length of the 8th lens (118) can be provided to be longer than the effective length of the 7th lens (117). Here, the effective length of the 7th and 8th lenses (117, 118) is the average of the effective lengths of the object side surface and the sensor side surface. The effective length of the 8th lens (118) can be provided to be longer than the effective length of the 6th lens (116).

[0142] The first lens (111) may have an effective length in the third direction (Z) that is shorter than the 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. Additionally, 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.

[0143]

[0144] Among the plurality of lens groups (LG1, LG2, LG3, LG4), at least one or all of the third and fourth lens groups (LG3, LG4) can be moved toward the object or 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 disposed on the outside of the third lens group (LG3) and at least one or a plurality of second driving members disposed on the outside of the fourth lens group (LG4), and can move the third lens group (LG3) and / or the fourth lens group (LG4) respectively in the direction of the optical axis (OA2) according to the operation mode.

[0145] The above operating mode may include a first mode for moving to take a picture at a first magnification as shown in FIG. 1, and a third mode for moving to take a picture at a second magnification higher than the first magnification as shown in FIG. 2b. Additionally, the above operating mode may include a second mode having a magnification between the first and third modes as shown in FIG. 2a. 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.

[0146] 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, the third lens group (LG3) and the fourth lens group (LG4) may each be located at a position defined as a first position (Position 1). In the second mode, the third lens group (LG3) and the fourth lens group (LG4) may each be located at a position defined as a second position (Position 2) that is closer to the object or prism (110) than the first position. In the third mode, the third lens group (LG3) and the fourth lens group (LG4) may each be located at a position defined as a third position (Position 3) that is closer to the object or prism (110) than the second position. The second position may be an area between the first and third positions. 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 (192) can be varied according to the operating mode. Accordingly, the optical system (100) can control the position of some lens groups according to the operating mode to control the effective focal length and magnification of the optical system (100).

[0147]

[0148] The maximum effective length (CA1) of the first lens (111) is the maximum among the lenses, and at least one of the effective lengths (CA3, CA4) of the third and fourth lenses (113, 114) is the minimum among the lenses. The maximum effective length (CA1) of the first lens (111) may be 8 mm or more. The effective lengths (CA3, CA4) of the third and fourth lenses (113, 114) may be 5.5 mm or less.

[0149] The effective length (CA) of each lens can satisfy the following conditions.

[0150] Condition 1: CA3 < CA2 < CA1 Condition 2: CA4 < CA3 < CA5

[0151] Condition 3: CA6 < CA7 < CA8 Condition 4: CA6 < CA5

[0152] The absolute 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, for example, it may be 1 mm or less. Since the center thickness (CT7) of the seventh lens (117) is 2.5 mm or more and the difference in the radius of curvature (absolute value) between the two surfaces (S13, S14) is provided to be small, 3 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.

[0153]

[0154] The optical axis distances of the first lens group (LG1) to the fourth lens group (LG4) are defined as TDLG1, TDLG2, TDLG3, and TDLG4, and may satisfy the following conditions.

[0155] Condition 1: 3mm < TDLG1 < 10mm

[0156] Condition 2: 1mm < TDLG2 < TDLG4 < 6mm

[0157] Condition 3: TDLG2 < TDLG4 < TDLG3 < TDLG1 < TDLG3*2

[0158] In terms of the absolute value of the focal length, the focal length (F7) of the seventh lens (117) may be the largest among the lenses. The difference in focal length (absolute value) between the first and second lenses (111, 112) may be the smallest among the differences in focal lengths of adjacent lenses. The focal lengths (F1~F8) of the first to eighth lenses (111-118) may satisfy the following conditions.

[0159] Condition 1: │F2│ < F1

[0160] Condition 2: 0 < │F2│ < │F3│ < │F4│ < 50mm

[0161] Condition 3: 0 < F5 < │F8│ < │F6│ < 40mm

[0162] Condition 4: (F5*3) < │F6│ < F7

[0163] Condition 5: │F6│ < F7 < (│F6│*3)

[0164]

[0165] When the compound focal length of the second to eighth lenses (112-118) aligned with the optical axis (OA2) is F28, the condition 0 < F28 can be satisfied, and it may be smaller than the absolute value of the focal length (FLG2) of the second lens group (LG2). Additionally, when the compound focal length of the moving lenses is F58, the condition 0 < F58 can be satisfied, and the condition F58 < F28 can be satisfied. The relationship between CG4, CG6, and BFL in the first, second, and third modes is as follows.

[0166] Mode 1: 2mm < BFL < CG6 < CG4 < 6mm

[0167] Mode 2: 1mm < CG6 < CG4 < BFL < 9mm

[0168] Third Mode: 0 < CG4 < CG6 < BFL < 11mm

[0169] In addition, for the first to third modes, CG4 can be defined as W-CG4, M-CG4, and T-CG4, satisfying the condition: T-CG4 < M-CG4 < W-CG4. W-CG4 is the interval in wide mode, M-CG4 is the interval in middle mode, and T-CG4 is the interval in tele mode. In addition, for the first to third modes, CG6 can be defined as W-CG6, M-CG6, and T-CG6, satisfying the condition: T-CG6 < M-CG6 < W-CG6. In addition, for the first to third modes (Wide mode, Middle mode, Tele mode), BFL can be defined as W-BFL, M-BFL, and T-BFL, satisfying the condition: W-BFL < M-BFL < T-BFL. Here, BFL is the optical axis distance from the sensor side of the fourth lens group (LG4) or the eighth lens (118) to the surface of the image sensor (192).

[0170] In the first, second, and third modes, the maximum travel distance of the third and fourth lens groups (LG3, LG4) is the travel distance (mMd13) in the first and third modes, defined as Max_mMd13, and can satisfy Max_mMd13 ≤ 7.5 mm, preferably 3 mm < Max_mMd13 < 7 mm. Accordingly, the maximum travel distance for zoom magnification is reduced, thereby reducing the power consumption of the driving member. Depending on the operating mode, the F-number of the optical system (100) provides a brightness of 4.0 or less, and the F-number may be in the range of 2.0 to 4.0. The aperture may be located between the second lens group (LG2) and the third lens group (LG3), and, for example, may be placed around the perimeter of the ninth surface (S9) of the fifth lens (115).

[0171]

[0172] FIG. 3 is an example showing the values ​​of an optical system according to an embodiment, wherein the lenses are defined as L1-L8 and the prism is P1, and the radius of curvature of each lens, the thickness of each lens and prism at the optical axis (CT), the distance between adjacent lenses at the optical axis (CG), the effective length (CA) of each lens surface (S1-S16, RS1, RS2), the Abbe number (Ad), the refractive index (Nd), and the effective focal length of each lens. FIG. 4 shows the conic constant (K) of the object-side and sensor-side surfaces of the third to eighth lenses (113-118) of FIG. 1 and the aspherical coefficients from the 4th to the 20th order (AI).

[0173] Table 1 is for items of the mathematical formulas described above in the optical system (100) of the embodiment, and shows the TTL of the optical system (100), the focal length of each lens group (FLG1-FLG4), ImgH (mm), and the optical axis distance of each lens group (TDLG1, TDLG2, TDLG3, TDLG4).

[0174] Item ExampleItem ExampleFLG1 (mm)197.860TDLG1 (mm)8.130FLG2 (mm)-16.700TDLG2 (mm)1.960FLG3 (mm)7.13TDLG3 (mm)4.700FLG4 (mm)-14.890TDLG4 (mm)4.170ImgH (mm)3.5TTL (mm)30.74

[0175]

[0176] Table 2 shows the effective focal length (F), field of view (FOV), F number (Fno), entrance pupil size (EPD), optical axis distance SD from the aperture to the sensor side of the last lens, optical axis distance TD from the first lens (111) to the last lens (118), and center spacing (CG2, CG4, CG6) between adjacent lens groups according to the first to third modes of the optical system according to the embodiment.

[0177] Item 1 Mode 2 Mode 3 F (mm) 11.85 15.80 19.75 CG2 (mm) 0.94 0.94 0.94 CG4 (mm) 4.4 22.38 0.52 CG6 (mm) 3.23 1.78 1.24 BFL (mm) 3.19 6.68 9.08 EPD (EPD1 / EPD2 / EPD3) 4.94 5.39 5.87 Fno (Fno1 / Fno2 / Fno3) 2.4 2.93 FOV (Degrees) 33.3 25.12 0.0 SD (mm) 12.10 10.64 10.11 TD (mm) 27.54 24.05 21.66

[0178]

[0179] FIGS. 5 to 7 are graphs showing longitudinal spherical aberration, astigmatic field curves, and distortion aberrations measured 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 focal length (mm) and distortion (%), and the Y-axis may represent the height of the image. Additionally, the graph for longitudinal spherical aberration is for light in wavelength bands of approximately 435 nm, approximately 486 nm, approximately 546 nm, approximately 587 nm, and approximately 656 nm, while the graphs for astigmatic field curves and distortion aberration are for light in the wavelength band of 546 nm. In the aberration graph, it can be interpreted that the closer each curve is to the Y-axis, the better the aberration correction function is, and it can be seen that the change in aberration according to the operating mode (wide, mid, tele modes) is not significant.

[0180] FIGS. 8 to 10 are graphs of light aberration characteristics according to the first, second, and third modes of an optical system according to an embodiment. The aberration graphs of FIGS. 8 to 10 are analysis graphs showing transverse aberrations for two different directions in the region where the relative field height on the optical axis in the tangential field curvature and sagittal field curvature of the optical system is 0.0 to 1.0. It can be confirmed that the characteristics of an optical system with good correction of transverse aberrations can be obtained for light in wavelength bands of approximately 435 nm, approximately 486 nm, approximately 546 nm, approximately 587 nm, and approximately 656 nm. That is, the camera module (100) according to the embodiment has improved resolution and can have good optical performance not only in the center of the field of view (FOV) but also in the periphery. The lens optical system of the embodiment according to the invention is composed of 8 lenses and prisms, making it compact and lightweight, while simultaneously correcting spherical aberration, astigmatism, distortion, chromatic aberration, and coma aberration well, so that high resolution can be achieved and thus it can be embedded in and utilized in the optical device of a camera.

[0181]

[0182] The optical system (100) according to the embodiment may satisfy at least one or two of the mathematical formulas described below. Accordingly, the optical system (100) according to the first embodiment can effectively correct aberrations that change according to the change in the operation mode. The optical system (100) can adjust the zoom magnification for a subject at various magnifications and may have a slim and compact structure. In the following, the distance between two adjacent lenses can be distinguished into a distance along the optical axis and an edge distance. The effective length of each lens or each lens surface (object side or sensor side) is indicated as the effective diameter when it is circular, and as the maximum effective length when it is non-circular. The thickness is the optical axis or center thickness, and the units of the distance, thickness, effective diameter, focal length, etc. are mm.

[0183] [Mathematical Formula 1] 40 mm ≤ FLG1

[0184] In Equation 1, FLG1 is the focal length of the first lens group (LG1), and the prism (110) of the first lens group (LG1) performs an OIS function, in which case the reduction in resolution caused by the first lens group (LG1) can be suppressed. Here, the focal length of the first lens group (FLG1) may be greater than the focal length of the second to fourth lens groups (FLG2, FLG3, FLG4). Equation 1 may satisfy 80mm < FLG1 < 250mm.

[0185] [Mathematical Equation 2] |L1R1|-|L2R2| ≤ 10mm

[0186] In Equation 2, L1R1 is the radius of curvature on the first optical axis (OA1) of the object-side first surface (S1) of the first lens (111), and L2R2 is the radius of curvature on the optical axis (OA2) of the sensor-side fourth surface (S4) of the second lens (112). By reducing the absolute difference in the radius of curvature between the first surface (S1) and the fourth surface (S4), the size of the beam propagating through the first lens group (LG1) can be reduced. Equation 2 can satisfy 1mm < |L1R1|-|L2R2| < 10mm.

[0187] [Mathematical Formula 3] 1 < CT1 / CT2 < 5

[0188] In mathematical formula 3, the center thickness (CT1) of the first lens (111) is greater than the center thickness (CT2) of the second lens (112), and if this is satisfied, the aberration characteristics in the optical system (100) can be improved. Preferably, 1 < CT1 / CT2 < 4 can be satisfied.

[0189] [Mathematical Equation 4] 1 < CT1 / CT3 < 5

[0190] In Equation 4, the center thickness (CT1) of the first lens (111) may be greater than the center thickness (CT3) of the third lens (113), and if this is satisfied, the optical system (100) can improve aberration characteristics. Equation 4 preferably satisfies 1 < CT1 / CT3 < 4.

[0191] [Mathematical Formula 4-1] 3mm < (CT5 + CT7) < 8mm

[0192] In Equation 4-1, since the sum of the center thickness (CT5) of the fifth lens (115) of the third lens group (LG3) and the center thickness (CT7) of the seventh lens (117) of the fourth lens group (LG4) exceeds 3 mm, the chromatic aberration characteristics of light passing through the third and fourth lens groups (LG3, LG4) can be improved. Equation 4-1 can preferably satisfy 4 mm < (CT5 + CT7) < 7 mm.

[0193] [Mathematical Formula 4-2] 5mm < (TDLG3 + TDLG4) < 12mm

[0194] In Equation 4-2, since the sum of the optical axis distance (TDLG3) of the third lens group (LG3) and the optical axis distance (TDLG4) of the fourth lens group (LG4) exceeds 5mm, the chromatic aberration characteristics of light passing through the third and fourth lens groups (LG3,LG4) can be improved. Equation 4-2 preferably satisfies 6mm < (TDLG3 + TDLG4) < 10mm.

[0195]

[0196] [Mathematical Formula 5] 0.5 < CT2 / CT3 < 2

[0197] In Equation 5, the center thickness (CT2) of the second lens (112) can set the center thickness (CT3) of the third lens (113), and if this is satisfied, the optical system (100) can improve aberration characteristics. Equation 5 preferably satisfies 0.6 < CT2 / CT3 < 1.5.

[0198] [Mathematical Formula 6] L1R1*L2R2 > 0

[0199] L1R1 is the radius of curvature of the first surface (S1) on the object side of the first lens (111), and L2R2 is the radius of curvature of the fourth surface (S4) on the sensor side of the second lens (112). If the optical system satisfies Equation 6, the amount of incident light from the prism (110) can be increased, and the increase in the spacing between the first and second lens groups (LG1, LG2) can be suppressed. Equation 6 preferably satisfies the range 100mm < L1R1*L2R2 < 2000mm.

[0200] [Mathematical Equation 7] FLG4 < 0

[0201] In Equation 7, FLG4 is the effective focal length of the fourth lens group (LG4) and can have a value less than 0. FLG4 is the compound focal length of the seventh and eighth lenses. If Equation 7 is satisfied, the optical aberration of the fourth lens group (LG4) of the optical system can be improved.

[0202] [Equation 8] 2 < TTL / TDLG1 < 5

[0203] In Equation 8, TDLG1 is the optical axis distance of the first lens group (LG1), for example, the distance along the optical axis (OA1, OA2) from the center of the first object-side surface (S1) of the first lens (111) to the center of the fourth sensor-side surface (S4) of the second lens (112). TTL refers to the distance along the optical axis (OA1, OA2) from the first object-side surface (S1) of the first lens (111) to the imaging surface of the image sensor (192). When the optical system (100) satisfies Equation 8, the optical system (100) has a relatively small TTL and can secure a peripheral light intensity ratio. Preferably, Equation 8 can satisfy 3 < TTL / TDLG1 < 5.

[0204]

[0205] [Equation 9] 2 < TTL / EPD3 < 7

[0206] In Equation 9, EPD3 represents the entrance pupil diameter (EPD) of the optical system (100) when operating in the third mode, that is, Tele mode. If the optical system (100) satisfies Equation 9, the optical system (100) can secure a bright image when operating in the third mode, and this may be a minimum condition for securing an F number of 4.0 or less in Tele mode. Preferably, 4 < TTL / EPD3 < 6 can be satisfied.

[0207] [Mathematical Formula 10] 2 < CT_Max / CT_Min < 9

[0208] In Equation 10, CT_Max is the thickest of the center thicknesses of the lenses and CT_Min is the thinnest of the center thicknesses of the lenses, and satisfying Equation 10 can improve the optical system aberration characteristics. Preferably, 4 < CT_Max / CT_Min < 8 can be satisfied.

[0209] [Mathematical Formula 11] 1 < CA_Max / CA_Min < 3

[0210] In Equation 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). If Equation 11 is satisfied, a camera module for a slim or compact structure can be provided while maintaining the optical performance of the optical system. Preferably, 1.5 < CA_Max / CA_Min < 2.5 can be satisfied.

[0211] [Mathematical Formula 12] 0.3 < ΣCT / TTL < 0.8

[0212] In Equation 12, ΣCT is the sum of the center thicknesses of the lenses. If the optical system satisfies Equation 12, the size of the optical system and camera module can be reduced. Preferably, 0.4 < ΣCT / TTL < 0.7 can be satisfied.

[0213] [Mathematical Formula 13] 2 < TDLG1 / TDLG2 < 8

[0214] In Equation 13, TDLG1 is the optical axis distance of the first lens group (LG1), and TDLG2 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 Equation 13, TTL can be adjusted. Preferably, 4 < TDLG1 / TDLG2 < 7 can be satisfied.

[0215] [Mathematical Formula 14] 0.5 < TDLG3 / TDLG4 < 1.5

[0216] In Equation 14, TDLG3 is the optical axis distance of the third lens group (LG3), and TDLG4 is the optical axis distance of the fourth lens group (LG4). Preferably, 0.8 < TDLG3 / TDLG4 < 1.3 can be satisfied. If the optical system (100) according to the embodiment satisfies at least one of Equation 13 and Equation 14, it has a relatively small TTL and can provide various magnifications according to at least three mode changes.

[0217]

[0218] [Mathematical Formula 15] 0 < CG2 / TTL < 0.2

[0219] In Equation 15, CG2 is the optical axis spacing between the second lens (112) and the third lens (113). If the optical system (100) satisfies Equation 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 / TTL < 0.15 can be satisfied.

[0220] [Mathematical Formula 16] 2 < TTL / (TDLG3 + TDLG4) < 7

[0221] Equation 16 sets the sum of the optical axis distances of the TTL and the third and fourth lens groups (LG3, LG4), and if the optical system (100) satisfies Equation 16, the optical system (100) has a relatively small TTL and can improve chromatic aberration characteristics. Preferably, 3 < TTL / (TDLG3+TDLG4) < 6 can be satisfied.

[0222] [Mathematical Formula 17] 5 < |Ad2 - Ad3| < 30

[0223] In Equation 17, Ad2 represents the Abbe number of the second lens, and Ad3 represents the Abbe number of the third lens. If the absolute value of the difference in Abbe numbers between the second and third lenses according to the embodiment satisfies Equation 17, the optical system (100) can improve chromatic aberration characteristics.

[0224] [Mathematical Formula 18] 15 < |Ad8 - Ad6| < 50

[0225] In mathematical formula 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 formula 18, the optical system (100) can improve chromatic aberration characteristics. Preferably, the conditions Ad6 < Ad8 and 45 < Ad8 can be satisfied.

[0226] [Mathematical Formula 19] 1.65 < Nd1

[0227] In Equation 19, Nd1 represents the refractive index of the first lens at the d-line. Since the first lens may be provided with a glass material, discoloration of the first lens can be prevented, damage from external exposure can be prevented, and heat dissipation characteristics can be improved. If the optical system (100) according to the embodiment satisfies Equation 19, incident light can be dispersed, and the effective area of ​​the lens placed on the sensor side rather than the first lens can be secured. Preferably, 1.7 ≤ Nd1 can be satisfied.

[0228] [Mathematical Equation 19-1] 1.65 < NP1

[0229] NP1 is the refractive index of the prism.

[0230] Here, the product of the Abbe number (Ad1) and refractive index (Nd1) of the first lens and the Abbe number (Ad8) and refractive index (Nd8) of the eighth lens can satisfy the following conditions.

[0231] Condition: Nd1*Ad1 < Nd8*Ad8

[0232] The product of the Abbe number (Ad2) and refractive index (Nd2) of the second lens and the Abbe number (Ad8) and refractive index (Nd8) of the eighth lens can satisfy the following conditions.

[0233] Condition: Nd2*Ad2 < Nd8*Ad8

[0234]

[0235] [Mathematical Formula 20] CG11 < 0.1mm

[0236] CG11 is the distance at the first optical axis (OA1) between the first lens and the prism. If Equation 20 is satisfied, the first lens and the prism can be in close contact. Preferably, the sensor-side second surface (S2) of the first lens can be attached to the incident surface of the prism.

[0237] [Mathematical Equation 20-1] CG12 < 0.1mm

[0238] CG12 is the distance along the optical axis (OA2) between the second lens and the prism. If Equation 20-1 is satisfied, the second lens and the prism can be in close contact. Preferably, the object-side third surface (S3) of the second lens can be attached to the exit surface of the prism.

[0239] [Mathematical Formula 21] L1R1 > 0

[0240] In mathematical formula 21, L1R1 represents the radius of curvature of the first surface (S1) on the object side of the first lens. When the optical system (100) satisfies mathematical formula 21, the optical system (100) can increase the amount of light incident on the first lens group (LG1) and control stray light.

[0241] [Mathematical Formula 22] L3R1 > 0

[0242] In mathematical formula 22, the radius of curvature on the optical axis (OA2) of the object side surface (S5) of the third lens of the second lens group (LG2) is set to a positive value, thereby reducing the beam size.

[0243] [Mathematical Formula 23] 0 < L1R1 / L3R1 < 2

[0244] In Equation 23, L1R1 represents the radius of curvature of the first object-side surface (S1) of the first lens on the first optical axis (OA1), and L3R1 represents the radius of curvature of the fifth object-side surface (S5) of the third lens on the optical axis (OA2). If Equation 23 is satisfied, the optical axis spacing between the first and second lens groups can be reduced, and the increase in beam size can be suppressed.

[0245] [Mathematical Equation 24] 0 < |L4R2 / L5R1| < 15

[0246] In Equation 24, L4R2 can set the radius of curvature of the sensor-side 8th surface (S8) of the 4th lens and the radius of curvature of the object-side 9th surface (S9) of the 5th lens on the optical axis (OA2). If the optical system (100) satisfies Equation 24, an optical path leading to the 2nd and 3rd lens groups can be set.

[0247] [Mathematical Formula 25] 2 < L1R1 / L8R2 < 9

[0248] L8R2 represents the radius of curvature of the sensor-side 16th surface (S16) of the 8th lens on the optical axis (OA2). Preferably, 3 < L1R1 / L8R2 < 8 can be satisfied. If Equation 25 is satisfied, the light path propagating through the 1st lens and the 8th lens can be controlled.

[0249] [Mathematical Formula 26] 0 < Md12_mLG3 / TTL < 0.5

[0250] In Equation 26, Md12_mLG3 represents the difference in center spacing after 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. Specifically, Md12_mLG3 represents the distance traveled by the third lens group (LG3) in the first and second modes, and represents the difference 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 (LG2, LG3) in the second mode. When the optical system (100) satisfies Equation 26, the optical system (100) can minimize the distance traveled by the third lens group (LG3) when changing the magnification, so the optical system (100) can have a slim structure. In addition, the distance traveled can be minimized when controlling the position of the third lens group (LG3), thereby providing improved power consumption characteristics. Preferably, 0 < Md12_mLG3 / TTL < 0.1 can be satisfied.

[0251]

[0252] [Equation 27] 0 < Md23_mLG3 / TTL < 0.5

[0253] In Equation 27, Md23_mLG3 represents the difference in 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 represents the difference 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 Equation 27, the optical system (100) can minimize the movement distance of the third lens group (LG3) when changing the magnification, so the optical system (100) can have a slim structure. In addition, the travel distance can be minimized when controlling the position of the third lens group (LG3), thereby enabling improved power consumption characteristics. Condition: 0 < Md23_mLG3 / TTL < 0.1 can be satisfied. Also, condition: Md12_mLG3 > Md23_mLG3 can be satisfied.

[0254] [Mathematical Formula 28] 0.1 < Md12_mLG3 / TDLG3 < 1

[0255] Equation 28 can set the movement distance (Md12_mLG3) of the third lens group (LG3) and the optical axis distance (TDLG3) of the third lens group (LG3) in the first and second modes. If the optical system (100) satisfies Equation 28, the optical system (100) can minimize the movement distance of the third lens group (LG3) when changing the magnification, so 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 it can have improved power consumption characteristics. Preferably, 0.25 < Md12_mLG3 / TDLG3 < 0.5 can be satisfied.

[0256] [Mathematical Formula 29] 0.1 < Md23_mLG3 / TDLG3 < 0.8

[0257] In Equation 29, Md23_mLG3 represents the difference in center spacing after 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. If the optical system (100) satisfies Equation 29, the optical system (100) can minimize the movement distance of the third lens group (LG3) when changing the magnification, so 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 it can have improved power consumption characteristics. Preferably, 0.3 < Md23_mLG3 / TDLG3 < 0.7 can be satisfied.

[0258] [Equation 30] 0 < Md23_mLG4 / TTL < 0.5

[0259] In Equation 30, Md23_mLG4 represents the difference in 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 represents the difference between the optical axis spacing between the fourth lens group (LG4) and the image sensor (192) in the second mode and the optical axis spacing between the fourth lens group (LG4) and the image sensor (192) in the third mode. When the optical system (100) satisfies Equation 30, the optical system (100) can minimize the movement distance of the fourth lens group (LG4) when changing the magnification, so 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. It can satisfy 0 < Md23_mLG4 / TTL < 0.2.

[0260] [Mathematical Formula 31] 0.1 < Md12_mLG4 / TDLG4 < 1

[0261] Equation 31 can set the travel distance of the fourth lens group (LG4) and the optical axis distance of the fourth lens group (LG4) in the first and second modes. If the optical system (100) satisfies Equation 31, the optical system (100) can minimize the travel distance of the fourth lens group (LG4) when changing the magnification, so the optical system (100) can have a slim structure. In addition, the travel distance can be minimized when controlling the position of the fourth lens group (LG4), so it can have improved power consumption characteristics. Preferably, 0.2 < Md12_mLG4 / TDLG4 < 0.7 can be satisfied.

[0262]

[0263] [Mathematical Equation 32] 1 < Md1(CG4 / CG6) < 3

[0264] In Equation 32, Md1(CG4 / CG6) represents the ratio between the center spacing (CG4) between the second and third lens groups and the center spacing (CG6) between the third and fourth lens groups in the first mode. If the optical system (100) according to the embodiment satisfies Equation 32, the optical system (100) may have improved optical characteristics at the first magnification. Specifically, the optical system (100) may have improved aberration characteristics at the first magnification and may improve the optical performance of the center and periphery of the field of view (FOV). Preferably, 1 < Md1(CG4 / CG6) < 1.6 may be satisfied.

[0265] [Mathematical Formula 33] 0.2 < Md3(CG4 / CG6) < 0.7

[0266] In Equation 33, Md3(CG4 / CG6) represents the ratio between the center spacing (CG4) between the second and third lens groups and the center spacing (CG6) between the third and fourth lens groups in the third mode. If the optical system (100) according to the embodiment satisfies Equation 33, the optical system (100) may have improved optical characteristics at the second magnification. Specifically, the optical system (100) may have improved aberration characteristics at the second magnification and may improve the optical performance of the periphery of the field of view (FOV). Preferably, 0.2 < Md3(CG4 / CG6) < 0.6 may be satisfied.

[0267] [Mathematical Formula 34] 2mm < Max_mMd13 ≤ 7.5mm

[0268] 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. If Equation 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 during movement can be reduced. Preferably, 3mm < Max_mMd13 < 7mm can be satisfied.

[0269] [Mathematical Formula 35] 1 < CA11 / CA22 < 3

[0270] CA11 is the effective length of the object side surface (S1) of the first lens, and CA22 is the effective length of the sensor side surface (S4) of the second lens. If Equation 35 is satisfied, the effective lengths of the incident side lens and the exit side lens of the prism can be set. Preferably, 1 < CA11 / CA22 < 2.3 can be satisfied.

[0271] [Mathematical Formula 36] 1 < CA12 / CA21 < 3

[0272] CA12 is the effective length of the sensor side surface (S2) of the first lens, and CA21 is the effective length of the object side surface (S3) of the second lens. If Equation 36 is satisfied, the effective lengths of the lens surfaces attached to the incident and exit surfaces of the prism can be set. Preferably, 1 < CA12 / CA21 < 2 can be satisfied.

[0273] [Equation 37] Md3_Fno ≤ 4.0

[0274] Md3_Fno is the F-number of the optical system in the third mode. If the optical system satisfies Equation 37, it can provide a bright optical system.

[0275] [Equation 38] 6mm < Md3_BFL < 12mm

[0276] Md3_BFL is the optical axis spacing between the fourth lens group and the image sensor when 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 the power consumption of the driving member and suppressing light loss.

[0277] [Mathematical Formula 39] 0.5 < BFL_Min / ImgH < 1.5

[0278] BFL_Min represents the minimum BFL value among the first to third modes, for example, the optical axis spacing between the eighth lens and the image sensor in the first mode. ImgH is half the diagonal length of the image sensor. If Equation 39 is satisfied, the minimum spacing between the image sensor and the last lens can be set. In addition, the minimum BFL required for a high-resolution image sensor can be secured.

[0279] [Equation 40] 5 < TTL / ImgH < 12

[0280] If the optical system (100) satisfies mathematical formula 40, the optical system (100) may have a smaller TTL, so the optical system (100) may be provided slim and compact. Preferably, it may be in the range 6 < TTL / ImgH < 10.

[0281] [Mathematical Formula 41] 2mm < ImgH

[0282] Equation 41 can set half of the diagonal length of the image sensor (192) and can provide the size of the image sensor of the zoom magnification optical system. Equation 41 can preferably satisfy 3mm < ImgH < 5mm.

[0283] [Mathematical Formula 42] 2 < │FLG1 / FLG2 │ < 20

[0284] In Equation 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 Equation 42 is satisfied, the size of the optical system can be reduced, for example, the TTL can be reduced. Preferably, FLG1 > 0 and FLG2 < 0.

[0285] [Mathematical Formula 43] 1 < FMd3 / FMd1 < 3

[0286] In Equation 43, FMd1 is the effective focal length of the optical system in the first mode, and FMd3 is the effective focal length of the optical system in the third mode. Preferably, 1.3 < FMd3 / FMd1 < 2 can be satisfied. If the optical system satisfies Equation 43, the effective focal length can be adjusted according to the first and third modes.

[0287] [Equation 44] 2 < FMd2 / EPD2 < 6

[0288] In Equation 44, FMd2 is the effective focal length of the optical system in the second mode (Middle mode), and EPD2 represents the size of the entrance pupil of the optical system (100) in the second mode. If the optical system (100) according to the embodiment satisfies Equation 44, the optical system (100) can secure a bright image during the second mode operation. Preferably, 2 < FMd2 / EPD2 < 4 can be satisfied.

[0289]

[0290] [Equation 45] 1 < FMd1 / EPD1 < 4

[0291] In Equation 45, FMd1 is the effective focal length of the optical system in the first mode (Wide mode), and EPD1 represents the size of the entrance pupil of the optical system (100) during operation in the first mode. If the optical system (100) according to the embodiment satisfies Equation 45, the optical system (100) can secure a bright image during operation in the first mode. Preferably, 2 < FMd1 / EPD1 < 3 can be satisfied.

[0292] [Equation 46] 1 < CA_Max / ImgH < 4

[0293] In Equation 46, CA_Max represents the largest effective length (CA) among the lens surfaces of the plurality of lenses included in the optical system (100). ImgH represents half the diagonal length of the image sensor (192), and represents half the diagonal length of the effective area of ​​the image sensor (192). If the optical system (100) according to the embodiment satisfies Equation 46, the optical system (100) can be provided in a slim and compact manner. In addition, the optical system (100) can achieve high resolution and high image quality.

[0294] [Equation 47] 2 < FMd1 / ImgH < 6

[0295] If the optical system (100) according to the embodiment satisfies Equation 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.

[0296] [Equation 48] 4 < FMd3 / ImgH < 10

[0297] If the optical system (100) according to the embodiment satisfies Equation 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, 5 < FMd3 / ImgH < 7 can be satisfied.

[0298] [Mathematical Formula 49] 1 < FMd3 / Max_mMd13 < 5

[0299] FMd3 is the effective focal length of the optical system in the third mode, and Max_mMd13 can set the maximum travel distance in the first to third modes. Preferably, 3 < FMd3 / Max_mMd13 < 4 can be satisfied.

[0300]

[0301] [Mathematical Formula 50] 10mm < TTL < 50mm

[0302] TTL refers to the distance along the optical axes (OA1, OA2) from the center of the first surface (S1) of the first lens to the surface of the image sensor (192). By setting TTL to exceed 10mm in Equation 50, a zoom magnification optical system can be provided. Preferably, 20mm < TTL < 40mm can be satisfied.

[0303] [Mathematical Equation 51] 8° < FOV3 < FOV2 < FOV1 < 45°

[0304] In mathematical formula 51, FOV (Field of view) refers to the angle of view (Degree) in the diagonal direction of the optical system (100), FOV1 represents the angle of view in the first mode, FOV2 represents 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 angles of wide, middle, and tele modes according to the operation mode. Preferably, 10° < FOV2 < 30° can be satisfied.

[0305] [Mathematical Formula 52] 3 < EPD1 < EPD2 < EPD3 < 9

[0306] EPD represents the entrance pupil size of the optical system (100), EPD1 represents the entrance pupil size in the first mode, EPD2 represents the entrance pupil size in the second mode, and EPD3 represents the entrance pupil size in the third mode.

[0307] [Mathematical Equation 53] 3 < ΣCT / n < 7

[0308] [Mathematical Formula 54] 30 < ΣAd / n< 37

[0309] [Mathematical Equation 55] 1 < ΣNd / n< 2

[0310] ΣCT is the sum of the center thicknesses of the first to eighth lenses and the sum of the thicknesses of the lenses excluding the thickness of the prism. ΣAd is the sum of the Abbe numbers of the first to eighth lenses and the sum of the Abbe numbers of the lenses excluding the Abbe number of the prism. ΣNd is the sum of the refractive indices of the first to eighth lenses and the sum of the refractive indices of the lenses excluding the refractive index of the prism. Here, n is the number of lenses excluding the prism, and can be 8. In a folded optical system having a prism, the center thicknesses, Abbe numbers, and refractive indices of the lenses are set to satisfy Equations 53-55, thereby preventing the degradation of optical properties and improving performance.

[0311]

[0312] [Mathematical Formula 56]

[0313]

[0314] In mathematical equation 56, Z can be Sag, which represents the distance in the direction of the optical axis from any position on the aspherical surface to the vertex of the aspherical surface. Additionally, Y can represent the distance in the direction perpendicular to the optical axis from any position on the aspherical surface to the optical axis. Furthermore, c can represent the curvature of the lens, and K can represent the conic constant. Additionally, A, B, C, D, E, and F can represent aspheric constants from the 4th to the 14th order.

[0315]

[0316] The optical system (100) according to the embodiment can satisfy at least one of the above-described mathematical formulas 1 to 55. Accordingly, the optical system (100) and the camera module can have improved optical characteristics. Specifically, as the optical system (100) satisfies at least one or two of the mathematical formulas 1 to 55, it can effectively correct for optical characteristic degradation such as chromatic aberration, vignetting, diffraction effects, and peripheral image quality degradation caused by the movement of the lens group. Furthermore, 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.

[0317] Table 3 shows the result values ​​for the above-described mathematical formulas 1 to 28 in the optical system (100) of the embodiment. It can be seen that the optical system (100) satisfies at least one, two or more, or three or more of mathematical formulas 1 to 28. Accordingly, the optical system (100) can have good optical performance in the center and periphery of the field of view (FOV) and can have excellent optical characteristics.

[0318] Mathematical formula value 140 mm ≤ FLG1197.8602|L1R1|-|L2R2| ≤ 105.96031 < CT1 / CT2 < 52.82541 < CT1 / CT3 < 52.26050.5 < CT2 / CT3 < 20.8006L1R1*L2R2 > 0219.1307FLG4 < 0-14.89082 < TTL / TDLG1 < 53.78192 < TTL / EPD3 < 75.237102 < CT_Max / CT_Min < 97.500111< CA_Max / CA_Min <31.911120.1 < ΣCT / TTL < 0.80.353133 < TDLG1 / TDLG2 < 84.148140.5 < TDLG3 / TDLG4 < 21.127150 < CG2 / TTL< 0.20.031162 < TTL / (TDLG3+TDLG4) < 73.466175 < |Ad2 - Ad3| < 3014.5001815 < |Ad8 - Ad6| < 5037.100191.65 < Nd11.82020CG11 < 0.1mm0.00021L1R1 > 018.08022L3R1 > 050.00230 < L1R1 / L3R1 < 20.362240 < |L4R2 / L5R1| < 159.329251 < L1R1 / L8R2 < 104.346260 < Md12_mLG3 / TTL < 0.50.066270 < Md23_mLG3 / TTL < 0.50.061280.3 < Md12_mLG3 / TDLG3 < 10.434

[0319] Table 4 shows the result values ​​for the above-described mathematical formulas 29 to 55 in the optical system (100) of the embodiments. It can be seen that the optical system (100) satisfies at least one, two or more, or three or more of mathematical formulas 29 to 55. Accordingly, the optical system (100) can have good optical performance in the center and periphery of the field of view (FOV) and can have excellent optical characteristics.

[0320] Equation value 290 < Md23_mLG3 / TDLG3 < 0.50.511300 < Md23_mLG4 / TTL < 0.30.078310 < Md23_mLG4 / TDLG4 < 10.576321< Md1 (CG4 / CG6) < 31.368330.2 < Md3 (CG4 / CG6) < 0.70.419342 < Max_mMd13 ≤ 7.55.900351 < CA11 / CA22 < 31.676361 < CA12 / CA21 < 31.52337Md3_Fno ≤ 4.03.400386 < Md3_BFL < 129.090390.5 < BFL_Min / ImgH < 1.50.91405 < TTL / ImgH < 128.783412 < ImgH3.500422 < │FLG1 / FLG2 │ < 2011.848431 < FMd3 / FMd1 < 31.667442 < FMd2 / EPD2 < 62.931451 < FMd1 / EPD1 < 42.399461 < CA_Max / ImgH < 42.686472 < FMd1 / ImgH < 63.386484 < FMd3 / ImgH < 105.643491 < FMd3 / Max_mMd13 < 53.3475010 < TTL < 5030.740518 < FOV3 <FOV2 < FOV1 < 45만족523 < EPD1 < EPD2 <EPD3 < 9만족533 < ΣCT / n < 71.365430 < ΣAd / n< 3736.5551 < ΣNd < 21.6

[0321]

[0322] FIGS. 11 to 17 describe detailed structures or variations of a prism or first lens group having power in an optical system according to an embodiment of the invention.

[0323] As shown in FIG. 11, the first lens (111) bonded to the incident surface (RS1) of the prism (110) may have a non-circular shape. The second lens (112) bonded to the exit surface (RS2) of the prism (110) may have a non-circular shape. The first lens (111) may have two sides in the first direction (X) parallel to each other. The first lens (111) may have two sides in the third direction (Z) parallel to each other. The distance between each edge in the first direction (X) of the first surface (S1) of the first lens (111) and the center of the first lens (111) may be different. The distance between each edge in the third direction (Z) of the second surface (S2) of the first lens (111) and the center of the first lens (111) may be different. The prism (110) to which the first lens (111) is joined can have power.

[0324]

[0325] The two sides of the second lens (112) in the first direction (X) may be parallel to each other. The two sides of the second lens (112) in the second direction (Y) may be parallel to each other. The distance between each edge in the first direction (X) of the third surface (S3) of the second lens (112) and the center of the second lens (112) may be different. The distance between each edge in the second direction (Y) of the fourth surface (S4) of the second lens (112) and the center of the second lens (112) may be different. The prism (110) to which the second lens (112) is joined may have power. The prism (110) to which the first and second lenses (111, 112) are joined may have power. The first surface (S1) of the first lens (111) may have a convex shape on the first optical axis (OA1), and the fourth surface (S4) of the second lens (112) may have a concave shape on the second optical axis (OA2). The second surface (S2) of the first lens (111) and the incident surface (RS1) of the prism (110) may be flat. The third surface (S3) of the second lens (112) and the exit surface (RS2) of the prism (110) may be flat.

[0326]

[0327] As shown in FIG. 12, the incident surface (RS1) of the prism (110) may have the shape of the convex first surface (S1) of the first lens (111) of FIG. 11. That is, the incident surface (RS1) of the prism (110) may have a convex shape. The lens (112) is attached to the exit surface (RS2) of the prism (110), and the incident surface (RS1) has a convex shape, so it may have power. The incident surface (RS1) of the prism (110) may have a convex shape on the first optical axis (OA1), and the fourth surface (S4) of the second lens (112) may have a concave shape on the second optical axis (OA2).

[0328] As shown in FIG. 13, the incident surface (RS1) of the prism (110) is joined to the first lens (111), and the exit surface (RS2) is joined to the second lens (112). The first surface (S1) of the first lens (111) may have a convex shape on the first optical axis (OA1), and the fourth surface (S4) of the second lens (112) may have a concave shape on the second optical axis (OA2). The second surface (S2) of the first lens (111) and the incident surface (RS1) of the prism (110) may be flat. The third surface (S3) of the second lens (112) and the exit surface (RS2) of the prism (110) may be flat.

[0329] The first and second lenses (111, 112) may have both sides in the first direction (X) parallel to each other. The first lens (111) may have both sides in the third direction (Z) parallel to each other. The second lens (112) may have both sides in the second direction (Y) parallel to each other. At least one of the corner regions (RS1c1) between adjacent sides of the first lens (111) may be a corner-cut region between adjacent sides of the first lens (111). The corner portion of the incident plane (RS1) of the prism (110) may be exposed in at least one or all of the corner portions (RS1c1) of the first lens (111). Accordingly, the effective area of ​​the first lens (111) may be equal to or smaller than the effective area of ​​the incident plane (RS1) of the prism (110). Accordingly, light incident through the first lens (111) can be incident on the incident surface (RS1) of the prism (110) without loss.

[0330] Here, the first lens (111) positioned on the incident side of the prism (110) or the first lens group (LG1) can be defined as the incident side lens, and the second lens (112) positioned on the exit side or sensor side of the prism (120) or the first lens group (LG2) can be defined as the exit side lens. Additionally, the lens positioned on the object side of each lens group can be defined as the incident side lens of each lens group, and the lens positioned on the exit side or sensor side can be defined as the exit side lens.

[0331] As shown in FIGS. 11 to 13, the prism (110) formed by joining the first and second lenses (111, 112) has positive power and may have a focal length of 40 mm or more. For example, the prism (110) formed by joining the incident side lens (111) and the exit side lens (112) has positive power and may have a focal length of 40 mm or more. Such a prism (110) can perform an OIS function and, having positive power, can improve the problem of reduced resolution. In addition, the first lens (111) may be made of a glass material with a refractive index of 1.7 or higher, which can reduce the diameter of the light passing through the prism (110). Also, the absolute difference in the radius of curvature between the prism (110) and the concave fourth surface (S4) of the convex first surface (S1) or convex incident surface (RS1) may be less than 10 mm. The radius of curvature of the first convex surface (S1) is S1R or the radius of curvature of the convex incident surface (RS1) is RS1R, and the radius of curvature of the fourth surface (S2) is S4R, and the following conditions can be satisfied.

[0332] Condition: -10 mm ≤ |S1R| -|S4R| ≤ 10 mm

[0333]

[0334] The radius of curvature of the above-mentioned fourth surface (S4) is S4R, and may satisfy at least one or all of the following conditions.

[0335] Condition 1: -7mm ≤ SR1 ≤ 35mm

[0336] Condition 2: -7mm ≤ RS1R ≤ 35mm

[0337] Condition 3: -7mm ≤ S4R ≤ 35mm

[0338] If the radius of curvature of the incident side surface (RS1, S1) and the exit side surface (S4) of the prism (110) is smaller than the above range, there is a problem that the resolution is further reduced during OIS, and if it is larger than the above range, there is a problem that the power is reduced and the F number increases. The distance between the second optical axis (OA2) between the prism (110) and the image sensor may be 20 mm or more, for example, in the range of 20 mm to 40 mm. If the optical axis distance between the prism and the second optical axis (OA2) between the image sensor is smaller than the above range, the optical sensitivity must be increased or the magnification must be reduced, and if it is larger than the above range, the module size may be increased.

[0339]

[0340] As shown in FIG. 14, the first surface (S1) and the second surface (S2) of the first lens (111) may each have a non-circular shape with different effective lengths in the first direction (X) and the third direction (Z). Specifically, the first surface (S1) of the first lens (111) may satisfy the condition: CA1z < CA1x when the effective length in the first direction (X) is CA1x and the effective length in the third direction (Z) is CA1z. With respect to the center of the first surface (S1), the two edges (S1a, S1b) in the first direction (X) may be provided as flat surfaces, and the two edges (S1c, S1d) in the third direction (Z) may be provided as flat surfaces. Here, the edge area of ​​the incident surface (RS1) of the prism (110) may be exposed to the adjacent edge area (RS1c1) of the first lens (111). That is, D1, which is half the diagonal length of the incident surface (RS1) of the prism (110), may be equal to or greater than D2, which is half the maximum length of the first lens (111). The length ratio (D1, D2) of the incident surface (RS1) of the prism (110) and the first lens (111) may satisfy the following conditions.

[0341] Condition: 0.67 ≤ D2 / D1 ≤ 1

[0342] D1 is the diagonal length from the center (P01) of the first lens (111) to the end of the prism (110), and D2 is half the maximum length or radius of the first lens (111). Under the above conditions, if it is smaller than the above range, the prism may be enlarged.

[0343]

[0344] Also, the effective length RA1x in the first direction (X) of the incident surface (RS1) of the prism (110)

[0345] In the case where the effective length in the third direction (Z) is RA1z, the condition RA1x = CA1x or RA1z = CA1z can be satisfied. The second surface (S2, prism side surface) of the first lens (111) may have an area less than or equal to the area of ​​the incident surface (RS1) of the prism (110). Accordingly, the first lens (111) may not protrude further outward than the side surface of the prism (110) in the first and third directions (X, Z), thereby suppressing the increase in the total length (ZL1) of the optical system (100). The distance between the two sides (S3a, S3b) of the second lens (112) in the first direction (X) may be the same as the distance in the first direction (X) of the first lens (111). The upper surface (S3c) of the second lens (112) in the second direction (Y) may not protrude further than the incident surface (RS1) of the prism (110).

[0346]

[0347] As shown in FIG. 15, the third surface (S3) and the fourth surface (S4) of the second lens (112) may each have a non-circular shape with different effective lengths in the first direction (X) and the second direction (Y). Specifically, the fourth surface (S4) of the second lens (112) may satisfy the condition: CA4y < CA4x when the effective length in the first direction (X) is CA4x and the effective length in the second direction (Y) is CA4y. With respect to the center of the fourth surface (S4), the two edges (S2a, S2b) in the first direction (X) may be provided as flat surfaces, and the two edges (S2c, S2d) in the second direction (Y) may be provided as flat surfaces. Here, the edge area of ​​the exit surface (RS2) of the prism (110) may be exposed to the adjacent edge area (RS2c2) of the second lens (112). That is, the lengths of the first and second directions (X,Y) of the exit surface (RS2) of the prism (110) may be equal to the lengths of the first and second directions (X,Y) (CA4x, CA4y) of the second lens (112). The third surface (S3) of the second lens (112) is a prism side surface and may have an area less than or equal to the area of ​​the exit surface (RS2) of the prism (110).

[0348] The prism (110) having the second lens (112) may have different lengths (D3, D4) in the second direction (Y) with respect to the center (P02) of the second lens (112). The center (P02) of the second lens (112) may be positioned closer to the lower edge (S2d) than the center line (L1) of the first direction (X) of the prism (110). The lengths (D3, D4) in the second direction (Y) of the prism (110) with respect to the center (P02) of the second lens (112) may satisfy the following conditions. Here, D3 is the length of the upper region or object-side region with respect to the center (P02), and D4 is the length of the lower region or object-side opposite region with respect to the center (P02).

[0349] Condition: 0.75 ≤ D4 / D3 ≤ 1

[0350] If the above conditions are smaller than the above range, the emitted beam may be cut, and a problem may occur where the light distribution is not symmetrical.

[0351]

[0352] In addition, the ratio of the length (CA4y) of the second direction (Y) of the second lens (112) to the length (CA1z) of the third direction (Z) of the first lens (111) may satisfy the following conditions.

[0353] Condition 1: CA4y ≤ CA1z

[0354] Condition 2: 0.4 ≤ CA1z / RA1x ≤ 0.75

[0355] The above length (CA1z) may be the length in the third direction (Z) of the first surface (S1) or the convex incident surface (RS1). The above length (CA4y) may be the length in the second direction (Y) of the concave exit surface (RS2). RA1x is the length in the first direction (X) of the prism (110). In condition 1, if the length of the exit-side lens is greater than the length of the incident-side lens, the module height may be increased. In condition 2, if the length (CA1z) in the third direction (Z) of the first lens (111) is smaller than the above range, the module size may be increased, and if it is larger than the above range, vignetting may occur.

[0356]

[0357] A layer for blocking light may be coated or applied to at least one of the incident side surface or / and the exit side surface of the prism or the first and second lenses described above. As shown in FIG. 16, the first surface (S1) of the incident side first lens (111) of the prism (110) may have an effective first region (RA1) and an ineffective first region (RB1). The ineffective first region (RB1) may be coated with a light-blocking layer (BM1) to block incident light entering through an unnecessary path. The light-blocking layer (BM1) may be made of carbon material, a black matrix, or a black dye. The fourth surface (S4) of the exit side second lens (112) of the prism (110) may have an effective second region (RA2) and an ineffective second region (RB2). The ineffective second region (RB2) may be coated with a light-blocking layer (BM2) to block light exiting through an unnecessary path. As another example, a light-blocking layer (not shown) may be formed in an ineffective area of ​​the second surface (S2) of the first lens (111). As another example, a light-blocking layer (not shown) may be formed in an ineffective area of ​​the third surface (S3) of the second lens (112).

[0358] As shown in FIG. 17, the incident surface (RS1) of the prism (110) has an effective third region (RA3) and an ineffective third region (RB3), and the ineffective third region (RB3) is coated with a light-blocking layer (BM3) and can block incident light entering through an unnecessary path. The exit surface (RS2) of the prism (110) may have an effective fourth region (RA4) and an ineffective fourth region (RB4). The ineffective fourth region (RB4) is coated with a light-blocking layer (BM4) and can block light exiting through an unnecessary path. The light-blocking layers (BM3, BM4) may be connected to each other.

[0359]

[0360] Referring to FIG. 18, the camera module has a first lens (111) and a prism (110) of an optical system (100) coupled in an opening area (101B) inside a first housing (101A) and can be exposed toward an object. A second lens may be coupled to the exit side of the prism (110) of the first housing (101A). A second housing (103A) is connected to the interior of the first housing (101A) and refracts light reflected through the prism (110) through the third to eighth lenses of the optical system (100) disclosed above. An image sensor and an optical filter, etc., may be coupled within the second housing (103A). The height of the upper surface (105) of the second housing (103A) may be lower than the upper surface of the first housing (101A). The first and second housings (101A, 103A) can be formed integrally.

[0361] A driving member is coupled inside the second housing (103A) to move the third and fourth lens groups along the optical axis direction. Additionally, a driving member for OIS of the prism (110) may be further disposed within the first housing (101A). The camera module can control the movement of the prism (110) by means of a control signal. Specifically, if shaking occurs in the camera module, information regarding the shaking, such as the degree of rotation and position change of the sensors, can be detected, and correction for the shaking can be performed. Accordingly, the camera module according to the embodiment can operate in wide mode, middle mode, and tele mode by means of a control signal, and can effectively correct shaking caused by rotation and shaking caused by position change when photographing a subject. Therefore, the camera module can have improved optical characteristics.

[0362]

[0363] FIG. 20 is a drawing illustrating a camera module according to an embodiment applied to an electronic device, such as a mobile phone.

[0364] As illustrated in FIG. 20, an electronic device (1000) according to one 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 shooting, and the other may perform telephoto shooting. The one performing telephoto shooting may include an 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 smartphone, the imaging device (1010) may also be a front camera of a smartphone. Additionally, although the electronic device (1000) is illustrated as a smartphone, the electronic device (1000) can be implemented in mobile devices such as PDAs, netbooks, tablet computers, laptop computers, etc., in addition to smartphones; wearable devices such as smartwatches, smart bands, smart glasses, etc.; computing devices such as desktops, servers, etc.; home appliances such as televisions, smart televisions, refrigerators, etc.; security devices such as door locks, CCTVs, etc.; vehicles such as autonomous vehicles, smart vehicles, etc.; cameras such as VR / AR cameras, 360-degree cameras, etc.; drones, etc.

[0365] Additionally, the portable electronic device (1000) may include a flash module (not shown) and an autofocus device (not shown). Here, the autofocus device (not shown) may include a surface-emitting laser element and a light receiver as a light-emitting layer. The flash module may include an emitter that emits light inside. The flash module may be operated by the operation of the camera of the electronic device or by control by a user. The autofocus device may include an autofocus function using a laser. The autofocus device may be mainly used under conditions where the autofocus function using the image of the camera module is degraded. Additionally, although not shown in the drawings, at least one additional camera module may be disposed on the front of the portable terminal. At least one of the camera modules within the portable terminal may have a tele-type folded lens assembly disclosed above.

[0366]

[0367] FIG. 20 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 generation unit (11), a first information generation unit (12), a second information generation unit (21, 22, 23, 24, 25, 26), and a control unit (14). The image generation unit (11) may include at least one camera module (31) disposed in the vehicle and may generate a front image of the vehicle or an interior image of the vehicle by photographing the front of the vehicle and / or the driver. The image generation unit (11) may generate an image of the vehicle's surroundings by photographing the vehicle's surroundings in one or more directions as well as the front of the vehicle using the camera module (31). Here, the front image and the surrounding image may be digital images and may include color images, black and white images, and infrared images. Additionally, the front image and the surrounding image may include still images and video images. The image generation unit (11) provides the driver image, the front image, and the surrounding image to the control unit (14). Subsequently, the first information generation unit (12) may include at least one radar or / and camera placed on the vehicle and generates first detection information by detecting the front of the vehicle. Specifically, the first information generation unit (12) is placed on the vehicle and generates first detection information by detecting the position and speed of vehicles located in front of the vehicle, the presence and location of pedestrians, etc.

[0368] By using the first detection information generated by the first information generation unit (12), the distance between the vehicle and the vehicle in front can be controlled to be maintained at a constant level, and the stability of vehicle operation can be increased in specific cases that are pre-set, such as when the driver wants to change the driving lane of the vehicle or when reverse parking. The first information generation unit (12) provides the first detection information to the control unit (14). The second information generation unit (21, 22, 23, 24, 25, 26) generates second detection information by detecting each side of the vehicle based on the front image generated by the image generation unit (11) and the first detection information generated by the first information generation unit (12). Specifically, the second information generation unit (21, 22, 23, 24, 25, 26) may include at least one radar or / and camera placed on the vehicle, and may detect the position and speed of vehicles located on the side of the vehicle or capture images. Here, the second information generating unit (21, 22, 23, 24, 25, 26) can be positioned at both front corners, side mirrors, and the rear center and both rear corners of the vehicle, respectively.

[0369] At least one information generating unit among such vehicle camera systems may be equipped with an optical system and a camera module having the same as described in the embodiment(s) disclosed above, and may provide to or process information obtained through the front, rear, each side, or corner area of ​​the vehicle to protect the vehicle and objects from autonomous driving or surrounding safety.

[0370] The optical system of the camera module according to an embodiment of the invention can be mounted in multiple units within a vehicle to comply with safety regulations, enhance autonomous driving functions, and increase convenience. Furthermore, the optical system of the camera module is applied within the vehicle as a component for control, such as a Lane Keeping Assistance System (LKAS), Lane Departure Warning System (LDWS), and Driver Monitoring System (DMS). Such a vehicle camera module can achieve stable optical performance even with changes in ambient temperature and provides a cost-competitive module, thereby ensuring the reliability of vehicle components.

[0371]

[0372] 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 only one embodiment. Furthermore, the features, structures, effects, etc. exemplified in each embodiment may be combined or modified and implemented in other embodiments by those skilled in the art to which the embodiments belong. Therefore, details regarding such combinations and modifications should be interpreted as being included within the scope of the present invention. Although the above description has focused on embodiments, this is merely an example and does not limit the present invention; those skilled in the art to which the present invention belongs will understand that various modifications and applications not exemplified above are possible within the scope that does not deviate from the essential characteristics of the embodiments. For example, each component specifically shown in the embodiments may be modified and implemented. Furthermore, differences related to such modifications and applications should be interpreted as being included within the scope of the present invention as defined in the appended claims.

Claims

1. Prism; A first lens attached to the incident surface of the above prism; A second lens attached to the exit surface of the above prism; and It includes a plurality of lenses disposed on the sensor side of the second lens, and The first lens has a shape in which the object-side surface is convex on the first optical axis, and The second lens and the plurality of lenses are aligned along a second optical axis that is orthogonal to the first optical axis, and An optical system in which the prism formed by joining the first lens and the second lens has a focal length of 40 mm or more.

2. An optical system according to claim 1, wherein the first lens has an asymmetrical shape and has a prism side surface having an area less than or equal to the area of ​​the incident surface of the prism.

3. An optical system according to claim 2, wherein the first lens is made of a glass material having a refractive index of 1.7 or higher.

4. An optical system according to any one of claims 1 to 3, wherein the absolute value of the difference in radius of curvature between the object-side surface of the first lens and the sensor-side surface of the second lens is 10 mm or less.

5. In any one of claims 1 to 3, 1 / 2 of the maximum effective length of the incident surface of the prism is D1, and 1 / 2 of the effective length of the first lens is D2, Condition: 0.67 ≤ D2 / D1 ≤ 1 An optical system satisfying .

6. In any one of paragraphs 1 to 3, An optical system in which the second lens has a concave shape on the second optical axis.

7. In any one of paragraphs 1 to 3, An optical system in which the center thickness of the first lens is thicker than the center thickness of the second lens.

8. In any one of paragraphs 1 to 3, The above plurality of lenses includes the third to eighth lenses, and The center thickness of the seventh lens is the thickest among the center thicknesses of the first to eighth lenses, in an optical system.

9. In any one of paragraphs 1 through 3, With respect to the center of the second lens, the length of the upper region of the exit surface of the prism is D3 and the length of the lower region is D4, and Condition: 0.75 ≤ D4 / D3 ≤ 1 An optical system satisfying .

10. In any one of paragraphs 1 to 3, An optical system having a light-blocking layer disposed in an ineffective area, wherein at least one of the incident surface of the prism, the exit surface of the prism, or the sensor side surface of the second lens.

11. Prism having an incident plane; An output-side lens attached to the output surface of the above prism; and It includes a plurality of lenses positioned on the sensor side of the above-mentioned emission-side lens, and The above incident surface has a convex shape on the first optical axis, and The above-mentioned emission-side lens and the above-mentioned plurality of lenses are aligned along a second optical axis that is orthogonal to the first optical axis, and An optical system in which the prism to which the above-mentioned exit-side lens is attached has a focal length of 40 mm or more.

12. An optical system according to claim 11, wherein the output side lens has a concave sensor side surface and a prism side surface having an area less than or equal to the area of ​​the output surface of the prism.

13. An optical system according to claim 11, wherein the exit-side lens has an asymmetrical shape and has a prism side surface area less than or equal to the area of ​​the exit surface of the prism.

14. In any one of paragraphs 11 through 13, With respect to the center of the above-mentioned exit-side lens, the length of the upper region of the exit surface of the prism is D3 and the length of the lower region is D4, and Condition: 0.75 ≤ D4 / D3 ≤ 1 An optical system satisfying .

15. An optical system comprising a first to fourth lens group; and an image sensor disposed on the sensor side of the fourth lens group, The optical system is the optical system of claim 1 or 11, and In the above optical system, the plurality of lenses are lenses of the second to fourth lens groups, and Each of the above second to fourth lenses has two lenses, and The third and fourth lens groups are a camera module that moves along the second optical axis.

Images