Optical system and camera module

Abstract

Disclosed in an embodiment of the present invention is a camera module comprising: a first lens group having a negative (-) refractive power; second and third lens groups disposed on a sensor side of the first lens group; and a fourth lens group disposed on a sensor side of the third lens group and having a negative (-) refractive power, in which the second and third lens groups perform zoom magnification from a wide-angle mode to a telephoto mode by moving along optical axes of lenses among the first to fourth lens groups, the number of lenses in at least one of the second lens group and the third lens group is larger than the number of lenses in the fourth lens group, and the optical axis distance of the second lens group is larger than the optical axis distance of the first lens group. And the fourth lens group may include a lens having a maximum effective length among effective lengths of the lenses in the first to fourth lens groups.

Description

Technical Field

[0001] Embodiments of the present invention relate to an optical system for improving optical performance and a camera module including the optical system. Background Technology

[0002] Camera modules capture objects and store them as images or videos, and are installed in a wide variety of applications. In particular, camera modules are manufactured in very small sizes and are used not only in portable devices such as smartphones, tablet PCs, and laptops, but also in drones and vehicles to provide a variety of functions. For example, the optical system of a camera module may include an imaging lens for forming an image, and an image sensor for converting the formed image into an electrical signal. In this case, the camera module can perform autofocus (AF) by automatically adjusting the distance between the image sensor and the imaging lens to align the lens's focal length, and can perform zoom functions by increasing or decreasing the magnification of a distant object via a zoom lens. Furthermore, camera modules employ image stabilization (IS) technology to correct or prevent image instability caused by unstable fixtures or camera movement due to user movement.

[0003] The most important component of this camera module for acquiring images is the imaging lens that forms the image. Recently, there has been increasing interest in high efficiency, such as high image quality and high resolution, and research is underway on optical systems incorporating multiple lenses to achieve this. For example, research is underway on using multiple imaging lenses with positive (+) and / or negative (-) refractive powers to achieve high-efficiency optical systems. However, a problem exists that when multiple lenses are included, it is difficult to obtain excellent optical and aberration characteristics. Furthermore, the thickness, spacing, and size of the multiple lenses can increase the overall length and height, thereby increasing the overall size of the module including the lenses.

[0004] As image sensors increase in size to achieve higher resolution and higher quality images, this increase also increases the total trace length (TTL) of the optical system. This leads to an increase in the thickness of the camera and mobile terminal, including the optical system.

[0005] When an optical system includes multiple lenses, functions such as zooming and autofocus (AF) can be performed by controlling the position of at least one lens or a lens group including at least one lens. However, when a lens or lens group performs these functions, the amount of movement of the lens or lens group can increase exponentially. Therefore, the optical system may require high energy to move the lens or lens group, and given the amount of movement, it may require a large volume. Furthermore, there is a problem that aberration characteristics deteriorate with the movement of the lens or lens group, causing a degradation in optical performance at a specific magnification. Therefore, a new optical system capable of solving the above problems is needed. Summary of the Invention

[0006] Technical Purpose

[0007] Embodiments of the present invention provide an optical system with improved optical properties. Embodiments provide an optical system and camera module capable of capturing images at various magnifications. Embodiments provide an optical system and camera module with improved aberration characteristics at various magnifications. Embodiments provide an optical system and camera module that can be implemented in a small and compact manner.

[0008] Technical solution

[0009] A camera module according to an embodiment of the present invention includes: a first lens group adjacent to an object and having negative refractive power; a second lens group disposed on the sensor side of the first lens group; a third lens group disposed on the sensor side of the second lens group; and a fourth lens group disposed on the sensor side of the third lens group and having negative refractive power, wherein the second and third lens groups are moved along the optical axes of the lenses in the first to fourth lens groups to perform a zoom ratio from wide-angle mode to telephoto mode, the number of lenses in at least one of the second and third lens groups is greater than the number of lenses in the fourth lens group, the optical axis distance of the second lens group is greater than the optical axis distance of the first lens group, and the fourth lens group may include a lens having the largest effective length among the effective lengths of the lenses in the first to fourth lens groups.

[0010] According to an embodiment of the present invention, the maximum moving distance of the second or third lens group according to the zoom ratio is Max_mMd13, and can satisfy the following mathematical expression: 1 mm < Max_mMd13 < 7 mm. The minimum optical axis distance between the first and second lens groups according to the telephoto mode is Md3_DG12, and can satisfy the following mathematical expression: 0.5 mm ≤ Md3_DG12 < 1.5 mm.

[0011] According to an embodiment of the present invention, the lens closest to the object in the first lens group may have positive refractive power and a meniscus shape convex toward the object.

[0012] The lens closest to the image sensor in the seventh lens group can have positive refractive power and a biconvex shape. This lens can be the one with the largest effective length among the first to fourth lens groups. The seventh lens can be made of glass. The first lens can have a spherical shape and can also be made of glass.

[0013] According to an embodiment of the invention, the number of lenses in the first lens group is the same as the number of lenses in the second and third lens groups, and each of the first to third lens groups may include lenses with refractive powers having opposite signs. The first lens group includes a reflective member arranged on the object side, and the lens closest to the image sensor may have a shape in which the effective lengths in the first and second directions perpendicular to the optical axis are different.

[0014] A camera module according to an embodiment of the present invention includes: a first lens group comprising first and second lenses arranged sequentially toward an image sensor on the object side and having negative refractive power; a second lens group disposed on the sensor side of the first lens group; a third lens group disposed on the sensor side of the second lens group; and a fourth lens group having a last lens disposed between the third lens group and the image sensor and having positive refractive power, wherein the second and third lens groups are movable along the optical axes of the lenses in the first to fourth lens groups to perform a zoom ratio from wide-angle mode to telephoto mode, the first lens having an object-side surface having a convex shape on the optical axis, and the sensor side of the first lens... The absolute value of the radius of curvature of the surface is greater than the radius of curvature of the object-side surface of the first lens. The first and fourth lens groups are fixed in place on the optical axis. The number of lenses in the second and third lens groups is less than the number of lenses in the fourth lens group. Among the optical axis distances of the first to fourth lens groups, the optical axis distance of the second lens group is the largest. The optical axis distance of the first to fourth lens groups is the distance from the object-side lens to the sensor-side lens in each lens group along the optical axis direction. The effective length of the first lens is less than the effective length of the last lens. The effective length of the first lens can be less than the effective length of the last lens, but greater than the effective length of the lenses in the second and third lens groups.

[0015] According to an embodiment of the present invention, the refractive index of the first lens is Nd1 and the Abbe number is Vd1, and the refractive index of the last lens is Ndn and the Abbe number is Vdn, and the following mathematical expression can be satisfied: Nd1 Vd1 < 50 and Ndn Vdn < 50. The optical system may include a reflecting member disposed on the object side of the first lens, and at least one of the first and last lenses may have shapes with different effective lengths in the first and second directions perpendicular to the optical axis. The second lens group may include a third and a fourth lens with refractive powers of opposite signs, the third lens group may include a fifth and a sixth lens with refractive powers of opposite signs, and the fourth lens group may include a seventh lens. The first lens may have a meniscus shape convex toward the object on the optical axis, the second lens may have a shape concave on both sides on the optical axis, the object-side lens of the second lens group may have a shape convex on both sides, and the seventh lens may have a shape convex on both sides on the optical axis.

[0016] According to an embodiment of the present invention, the total focal length in wide-angle mode is FMd1, the total focal length in telephoto mode is FMd3, and half the diagonal length of the image sensor is ImgH, satisfying the following mathematical expressions: 2 < FMd1 / ImgH < 6 and 6 < FMd3 / ImgH < 12. An aperture stop is included, arranged peripherally between the first and second lens groups. In wide-angle mode, the optical axis distance from the aperture stop to the surface of the image sensor is SD1, and the optical axis distance from the object-side surface of the first lens to the surface of the image sensor is TTL, satisfying the following mathematical expression: 0.5 < SD1 / TTL < 1. In telephoto mode, the F-number of the optical system is Md3_Fno, satisfying the condition: Md3_Fno ≤ 5.

[0017] The effective length of the lenses arranged in the second and third lens groups can be less than the diagonal length of the image sensor.

[0018] A camera module according to an embodiment of the present invention includes: a reflecting member that reflects a second optical axis of incident light to a first optical axis; a first lens group disposed on the output side of the reflecting member and having negative refractive power; a second lens group disposed on the sensor side of the first lens group and having positive refractive power; a third lens group having negative refractive power and disposed on the sensor side of the second lens group; a fourth lens group having negative (+) refractive power and disposed on the sensor side of the third lens group; a first driving member for moving the second lens group along the first optical axis; and a second driving member for moving the third lens group along the first optical axis, wherein the second and third lens groups move along the first optical axis of the lenses in the first to fourth lens groups to perform a zoom ratio from a wide-angle mode to a telephoto mode, and the first to fourth lenses... The total number of lenses in the group is 6 or more. The refractive index of the first lens closest to the object and the nth lens closest to the image sensor is greater than 1.6. Among the lenses in the first to fourth lens groups, the nth lens has the largest effective length. The maximum moving distance of the second lens group according to the zoom ratio is Max_mLG2, and the maximum moving distance of the third lens group according to the zoom ratio is Max_mLG3. The optical axis distance from the object-side first lens of the first lens group to the surface of the image sensor is TTL. Half of the diagonal length of the image sensor is ImgH, and the following mathematical expressions can be satisfied: 5 < TTL / Max_mLG2 < 5.6, 5.2 < TTL / Max_mLG3 < 5.8, and 5 < TTL / ImgH < 12.

[0019] Technical effect

[0020] The optical system and camera module according to the embodiments can have various magnifications and exhibit excellent optical characteristics when providing various magnifications. Specifically, the embodiments can control the movement distance of each moving lens group to achieve various magnifications and provide autofocus (AF) functionality for the object. The optical system and camera module according to the embodiments can compensate for or complement aberration characteristics of multiple lens groups that change due to movement. Therefore, the optical system according to the embodiments can minimize or prevent changes in chromatic aberration and aberration characteristics that occur when the magnification changes.

[0021] The optical system and camera module according to the embodiments can control the effective focal length (EFL) by moving only some of the multiple lens groups and minimizing the movement distance of the moving lens groups. Therefore, the optical system can reduce the movement distance of the moving lens groups according to changes in operating modes and minimize the power consumption required when moving the lens groups. The optical system may have at least one lens with a non-circular shape included in both the fixed and moving groups. Therefore, the optical system can reduce its height while maintaining optical performance and ensure sufficient space for structurally arranging the lens groups among the multiple lens groups.

[0022] The optical system and camera module according to the embodiment can adjust the magnification by moving the lens groups other than the first lens group adjacent to the object. Therefore, even when the lens groups move due to changes in magnification, the optical system can maintain a constant TTL value. Thus, the optical system and the camera module including the optical system can be configured with a thinner structure. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of an optical system and a camera module including the optical system according to a first embodiment of the present invention.

[0024] Figure 2 It shows Figure 1 An example of the operation of the first mode in an optical system.

[0025] Figure 3 Show Figure 1 and Figure 2 An example of the operation of the third mode in an optical system.

[0026] Figure 4 This is a table of lens data for an optical system according to the first embodiment of the present invention.

[0027] Figure 5 This is a table showing the aspherical coefficients of the lenses of an optical system according to a first embodiment of the present invention.

[0028] Figure 6 It is a graph of the diffraction MTF in the optical systems of wide-angle mode, intermediate mode and telephoto mode according to the first embodiment of the present invention.

[0029] Figure 7 It is shown Figure 2 A graph showing the aberration characteristics in the first-mode optical system.

[0030] Figure 8 It is shown Figure 1 A graph showing the aberration characteristics in the second-mode (intermediate-mode) optical system.

[0031] Figure 9 It is shown Figure 3 A graph showing the aberration characteristics in the optical system of the third mode (telephoto mode).

[0032] Figure 10 This is a schematic diagram of an optical system and a camera module including the optical system according to a second embodiment of the present invention.

[0033] Figure 11 It shows Figure 10 An example of first-mode operation in an optical system.

[0034] Figure 12 It shows Figure 10 and Figure 11 An example of the operation of the third mode in an optical system.

[0035] Figure 13 This is a table of lens data for an optical system according to a second embodiment of the present invention.

[0036] Figure 14 This is a table showing the aspherical coefficients of the lenses of an optical system according to a second embodiment of the present invention.

[0037] Figure 15 This is a graph of the diffraction MTF in the optical systems of wide-angle mode, intermediate mode and telephoto mode according to the second embodiment of the present invention.

[0038] Figure 16 It is shown Figure 11 A graph showing the aberration characteristics in a first-mode optical system.

[0039] Figure 17 It is shown Figure 10 A graph showing the aberration characteristics in the second-mode (intermediate-mode) optical system.

[0040] Figure 18 It is shown Figure 12 A graph showing the aberration characteristics in the optical system of the third mode (telephoto mode).

[0041] Figure 19 This is a schematic diagram of an optical system and a camera module including the optical system according to a third embodiment of the present invention.

[0042] Figure 20 yes Figure 19 An example of variations in the first mode of an optical system.

[0043] Figure 21 yes Figure 19 and Figure 20 An example of variations in the third mode of an optical system.

[0044] Figure 22 This is a table of lens data for an optical system according to a third embodiment of the present invention.

[0045] Figure 23 This is a table showing the aspherical coefficients of the lenses of an optical system according to a third embodiment of the present invention.

[0046] Figure 24 This is a graph of the diffraction MTF in the optical systems of wide-angle mode, intermediate mode and telephoto mode according to the third embodiment of the present invention.

[0047] Figure 25 It is shown Figure 20 A graph showing the aberration characteristics in the first-mode optical system.

[0048] Figure 26 It is shown Figure 19 A graph showing the aberration characteristics in the second-mode (intermediate-mode) optical system.

[0049] Figure 27 It is shown Figure 21 A graph showing the aberration characteristics in the optical system of the third mode (telephoto mode).

[0050] Figure 28 This is a plan view illustrating an example of a lens with a D-shaped cut in an optical system according to the first to third embodiments of the present invention.

[0051] Figure 29 This is a side sectional view illustrating examples of reflective members in an optical system and camera module according to the first, second, and third embodiments of the present invention.

[0052] Figure 30 This is an illustration of a camera module applied to a mobile terminal according to an embodiment of the present invention. Specific Implementation

[0054] Preferred embodiments of the invention will be described in detail below with reference to the accompanying drawings. The spirit of the invention is not limited to the embodiments described herein, and may be implemented in various other forms. One or more components may be selectively combined and substituted within the scope of the spirit of the invention. Furthermore, the terminology used in the embodiments of the invention (including technical and scientific terms) is to be interpreted in a meaning that is generally understood by one of ordinary skill in the art to which this invention pertains, unless specifically defined and explicitly described, and common terms (such as those defined in dictionaries) should be interpretable in light of the contextual meaning of the relevant art.

[0055] Furthermore, the terminology used in the embodiments of the present invention is for illustrative purposes and is not intended to limit the invention. In this specification, unless specifically stated otherwise in the phrase, the singular form may also include the plural form, and in the case of describing at least one (or one or more) of A and (and) B, C, it may include one or more of all combinations that can be combined with A, B, and C. In describing components of embodiments of the present invention, terms such as first, second, A, B, (a), and (b) may be used. Such terms are used only to distinguish the component from other components and cannot be determined by the nature, sequence, or process of the corresponding constituent elements. Furthermore, when describing a component as being “connected,” “joined,” or “engaged” to another component, the description may include not only direct connection, joining, or engagement to another component, but also connection, joining, or engagement by another component between the component and other components. In the case of descriptions of being formed or disposed “above” or “below” each component, the description includes not only when the two components are in direct contact with each other, but also when one or more other components are formed or disposed between the two components. In addition, when expressed as "above" or "below", it can refer to the downward and upward directions with respect to a component.

[0056] In this specification, the convexity of a lens surface can refer to a convex shape of the lens surface in the region corresponding to the optical axis or the paraxial region, and the concavity of a lens surface can refer to a concave shape of the lens surface in the region corresponding to the optical axis or the paraxial region. Furthermore, "object-side surface" can refer to the surface of a lens facing the object side based on the optical axis, and "sensor-side surface" can refer to the surface of a lens facing the imaging surface (image sensor) based on the optical axis. Additionally, the center thickness of the lens can refer to the thickness of the lens along the optical axis. Furthermore, the vertical direction can refer to the direction perpendicular to the optical axis, and the end of the lens or lens surface can refer to the end of the effective area of ​​the lens through which incident light passes. Furthermore, depending on the measurement method, the effective diameter of the lens surface can have a measurement error of up to ±0.4 mm.

[0057] like Figure 1 , Figure 10 and Figure 19As shown, the optical system 1000 according to an embodiment of the present invention may include a plurality of lens groups. The plurality of lens groups may include at least three lens groups. The plurality of lens groups include first to fourth lens groups LG1 to LG4. Each of the plurality of lens groups includes at least one lens. The first to fourth lens groups LG1 to LG4 may be arranged sequentially along the optical axis OA from the object toward the image sensor 300. The optical system 1000 may include n lenses, where 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 6, for example, 6 to 9. Within the optical system 1000, lenses may be defined as lens portions 100, 100A, and 100B.

[0058] Among the plurality of lens groups, at least two lens groups can be fixed groups with fixed positions, and at least two lens groups can be variable groups with variable positions. For example, the first lens group LG1 adjacent to the object and the fourth lens group LG4 adjacent to the image sensor 300 can be fixed groups, and at least one lens group LG2 and LG3 between the first lens group LG1 and the fourth lens group LG4 can be variable groups with variable positions. Here, the variable groups can reciprocate along the optical axis. With the movable lens groups, the optical system 1000 can provide a continuous zoom optical system with wide-angle mode, intermediate mode, and telephoto mode. The second lens group LG2 is arranged between the first lens group LG1 and the third lens group LG3, and can be moved for zoom magnification. The third lens group LG3 is positioned between the second lens group LG2 and the third lens group LG3, and can be moved for focusing. The moving distance of the movable lens groups can be set to a maximum value of 7 mm, thereby reducing the power consumption of the drive unit. Furthermore, in telephoto mode, the optical axis distance DG12 between the first lens group LG1 and the second lens group LG2 can be set to 0.5 mm or greater, for example, 0.8 mm, thereby reducing the movement distance of the second lens group LG2 and the third lens group LG3 and providing a high-magnification optical system.

[0059] The number of lenses in the first lens group LG1 and the second lens group LG2 can be the same or different. For example, the number of lenses in the first lens group LG1 can be equal to the number of lenses in the second lens group LG2. The number of lenses in each of the second lens group LG2 and the third lens group LG3 can be the same or different, and can be, for example, two or fewer. For example, the number of lenses in the third lens group LG3 can be the same as the number of lenses in the second lens group LG2. The number of lenses in the fourth lens group LG4 can be less than the number of lenses in each of the second lens group LG2 and the third lens group LG3, and can be, for example, one. The number of lenses in the first lens group LG1 can be at least twice the number of lenses in the fourth lens group LG4. By stacking these lens numbers, optical systems with wide-angle, intermediate, and telephoto modes can be provided, and depending on the operating mode, a bright optical system with an F-number ranging from 2.2 to 5 can be provided.

[0060] At least one or all of the lenses in the first to fourth lens groups LG1-LG4 can be made of plastic material. Furthermore, plastic material can be used to arrange the lenses in the movable lens groups LG2 and LG3 to prevent increased power consumption of the drive components. As another example, each of the movable lens groups LG2 and LG3 can include a plastic lens and a glass lens. As another example, the lens closest to the object in the fixed lens group LG1 can be made of glass. As another example, the lens closest to the image sensor in the lens group can be made of glass. At least one or all of the lens surfaces in the first to fourth lens groups LG1-LG4 can have an aspherical shape on the optical axis, or at least one lens surface can have a spherical surface. Lenses with aspherical surfaces can prevent spherical aberration in the optical system 1000, and since no aberration occurs even with an increase in effective diameter, the camera module can be miniaturized and its weight reduced. Aspherical lenses can be made of glass molds or plastic material. Spherical lenses can be made of glass.

[0061] The refractive power of the first lens group LG1 can have the opposite sign to that of the second lens group LG2. The refractive power of the first lens group LG1 can be negative, and the refractive power of the second lens group LG2 can be positive. The refractive power of the third lens group LG3 can have the opposite sign to that of the fourth lens group LG4. The refractive power of the third lens group LG3 can be negative, and the refractive power of the fourth lens group LG4 can be positive. Among the lenses in the optical system 1000, the number of lenses with positive refractive power can be greater than the number of lenses with negative refractive power.

[0062] 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, and the condition │FLG3│ < FLG4 can be satisfied. The absolute values of the focal lengths of the first lens group LG1 and the fourth lens group LG4 with fixed positions can be greater than the absolute values of the focal lengths of the second lens group LG2 and the third lens group LG3. Here, FLG1, FLG3 < 0 and FLG2, FLG4 > 0 can be satisfied. The optical system 1000 can adjust the field of view (FOV) through the refractive power of each of the first to fourth lens groups LG1-LG4.

[0063] In the first lens group LG1, the first lenses 101, 111, and 121 closest to the object and the second lenses 102, 112, and 122 closest to the second lens group LG2 can have refractive powers with opposite signs. Therefore, the first lens group LG1 can mutually compensate for the chromatic aberration caused by the multiple lenses included in the first lens group LG1. For example, the first lenses 101, 111, and 121 can have positive refractive powers, and the second lenses 102, 112, and 122 can have negative refractive powers. Here, the Abbe number LG1_Vd2 of the last lens of the first lens group LG1 can satisfy the following condition: LG1_Vd2 < 35, for example, 20 < LG1_Vd2 < 35. Under these conditions, the first lens group LG1 can disperse the incident light to the periphery of the second lens group LG2. In addition, the sensor-side surface S4 of the lens closest to the second lens group LG2 within the first lens group LG1 can have a concave shape on the optical axis. Therefore, the concave sensor-side surface S4 of the first lens group LG1 can refract the light toward the moving second lens group LG2, thereby reducing the light loss toward the second lens group LG2 in the region between the first lens group LG1 and the second lens group LG2.

[0064] The Abbe number LG2_Vd1 of the lens closest to the first lens group LG1 within the second lens group LG2 can satisfy the following condition: 35 < LG2_Vd1, for example, 35 < LG2_Vd1 < 65. Under these conditions, the second lens group LG2 can refract the incident light in the direction of the optical axis of the third lens group LG3. At least two lenses in the second lens group LG2 can have refractive powers with opposite signs. Therefore, the second lens group LG2 can mutually compensate for the chromatic aberration caused by the multiple lenses included in the second lens group LG2. When the Abbe numbers of at least two lenses in the second lens group LG2 are LG2_Vd1 and LG2_Vd2, the following condition can be satisfied: │LG2_Vd1 - LG2_Vd2│ > 20, and when this condition is satisfied, the change in chromatic aberration due to magnification adjustment (zooming) can be minimized.

[0065] At least two lenses in the third lens group LG3 may have refractive powers with the same sign. When the Abbe numbers of at least two lenses in the third lens group LG3 are LG3_Vd1 and LG3_Vd2, the following condition may be satisfied: │LG3_Vd1–LG3_Vd2│>20, and when this condition is satisfied, the change in chromatic aberration due to aberration correction may be minimized. In addition, the refractive power of the third lens group LG3 may have a negative value to control the influence in the focusing direction. Each of the first to fourth lens groups LG1-LG4 may have at least one lens with a positive refractive power to reduce the influence of aberration.

[0066] The refractive index LG4_Nd of the lenses in the fourth lens group LG4 may satisfy the following condition: 1.6 < LG4_Nd1, for example, 1.6 < LG4_Nd1 < 1.8. According to this condition, the lenses of the fourth lens group LG4 may refract incident light toward the center and periphery of the image sensor 300. The fourth lens group LG4 may function to control the chief ray angle of incidence (CRA). Specifically, the optical system 1000 according to an embodiment may have a CRA less than about 20 degrees and may correct the CRA of the light incident on the image sensor 300 to be close to 0 degrees. When the sum of the refractive indices of the lenses in the optical system 1000 is ∑Nd and the sum of the Abbe numbers is ∑Vd, the following conditions may be satisfied.

[0067] Condition 1: 8 < ∑Nd < 12

[0068] Condition 2: 200 < ∑Vd < 260

[0069] By adjusting the refractive indices and Abbe numbers of the lenses in the optical system 1000, aberration can be controlled. Among the lenses in the optical system 1000, the lens with the largest Abbe number may be positioned in the second lens group LG2 and the third lens group LG3. Among the lenses in the optical system 1000, the average refractive index of the lenses in the first lens group LG1 and the fourth lens group LG4 may be greater than 1.6, and the average refractive index of the lenses in the second lens group LG2 and the third lens group LG3 may be 1.6 or less. The lens with the largest Abbe number may reduce dispersion, and the lenses with a refractive index greater than 1.6 may increase the dispersion of incident light.

[0070] Each lens of the optical system 1000 may include an effective region and an ineffective region. The effective region can be the area through which light incident on each lens passes. In other words, the effective region can be defined as the effective area or effective diameter through which incident light is refracted to achieve optical properties. The ineffective region may be located around the effective region. The ineffective region can be a region where effective light does not enter from the plurality of lenses. In other words, the ineffective region can be a region unrelated to optical properties. Furthermore, the ends of the ineffective regions may be areas fixed to a lens barrel (not shown) that houses the lens.

[0071] The average effective length of the object-side surface and sensor-side surface of each lens in lens sections 100, 100A, and 100B can be set to 7 mm or less, for example, in the range of 4 mm to 7 mm. Here, the average effective length can be the average of the effective lengths of the object-side surface and sensor-side surface of each lens. Here, the effective length can be the maximum length when the object-side surface and sensor-side surface have different lengths in the first and second directions perpendicular to the optical axis. The lens with the maximum effective length within lens sections 100, 100A, and 100B can be the last lens. For example, the effective length of the last lenses 107, 117, and 127 can be greater than the effective length of the first lenses 101, 111, and 121. The maximum effective length of the object-side surface S1 of the first lenses 101, 111, and 121 can be shorter than the maximum effective length of the sensor-side surface S6 of the last lenses 103, 113, and 123. Furthermore, the first lenses 101, 111, and 121 can be provided with a larger effective length than the other lenses except the last lens, thereby preventing a reduction in the amount of incident light.

[0072] The effective lengths of the first and last lenses closest to the object can satisfy the following condition: Condition: 0.75 <CA11 / CAn2<0.95 CA11 is the effective length of the object-side surface of the first lens, and CAn2 is the effective length of the sensor-side surface of the last (nth) lens. Satisfying this condition reduces the TTL. TTL is the optical axis length from the center of the object-side surface of the first lenses 101, 111, and 121 to the surface of the image sensor 300.

[0073] like Figure 28As shown, at least one or two or more lenses within the optical system 1000 may have different effective lengths C1 and C2 in a first direction X and a second direction Y perpendicular to the optical axis OA. The first direction X and the second direction Y may be orthogonal to each other. The lens L1, having different effective lengths C1 and C2 along the first direction X and the second direction Y, may have a non-circular shape or a D-shaped cut. For example, the effective length C2 along the first direction X may be shorter than the effective length C1 along the second direction Y. The first direction X may be a direction perpendicular to the thickness direction of the device equipped with the camera module (such as a portable terminal or display surface). At least one or both of the object-side and sensor-side surfaces S21 of the lens L1 may have a non-circular shape, and the length C12 of both sides CS1 and CS2 along the first direction X may be less than the maximum effective length C1.

[0074] At least one of the lenses in the first lens group LG1 may have effective lengths of object-side surfaces and / or sensor-side surfaces that are different from each other, and the effective length along the first direction X may be less than the effective length along the second direction Y. At least one of the lenses in the second lens group LG2 may have effective lengths of object-side surfaces and / or sensor-side surfaces that are different from each other, and the effective length along the first direction X may be less than the effective length along the second direction Y. The effective lengths of the object-side surfaces and / or sensor-side surfaces of the seventh lenses 107 and 117 in the fourth lens group LG4 may be different from each other, and the effective length along the first direction X is shorter than the effective length along the second direction Y. Specifically, among the lenses in lens sections 100, 100A, and 100B, the seventh lenses 107, 117, and 127, which have the largest effective lengths, have an effective length along the second direction greater than their effective length along the first direction X. The first lenses 101, 111, and 121 may have an effective length along the second direction Y that is longer than their effective length along the first direction X.

[0075] When the lengths of the object side surface S1 of the m-th lens along the first direction X and the second direction Y are different, the maximum effective length along the second direction Y is CAm1y, and the minimum effective length along the second direction X is CAm1x, then the condition of the following formula can be satisfied: 0.55 < CAm1x / CAm1y < 0.98, and m can be 1.8. When the lengths of the sensor side surface (CAm2) of the m-th lens along the first direction X and the second direction Y are different, the maximum effective length along the second direction Y is CAm2y, and the minimum effective length along the first direction X is CAm2x, then the condition of the following formula can be satisfied: 0.55 < CAm2x / CAm2y < 0.98, and m can be 1.8. If the value of the formula in the effective length of the object side or the sensor side surface of the m-th lens is less than 0.55, it is difficult to manufacture the object side or the sensor side surface of the m-th lens into a non-circular shape, and it is difficult to control the distribution of incident light. If it exceeds 0.98, the reduction of the size of the optical system along the second direction may be minimized. By restricting the maximum effective lengths of the object side surfaces and the sensor side surfaces of at least two lenses having the maximum effective length along the first direction X to the above range, an increase in the thickness of the mobile terminal equipped with the camera module can be prevented.

[0076] The optical system 1000 according to an embodiment can have improved assemblability through (one or more) non-circular lenses and has a mechanically stable form. In addition, the optical system 1000 can significantly reduce the moving distance of the moving lens group and provide various magnifications. Further, since the lens having a large effective length along the second direction Y is provided in a shape in which both sides along the second direction Y are cut off, the height or thickness of the optical system 1000 and the camera module along the second direction Y can be reduced. Accordingly, an increase in the thickness of the device having the thin optical system 1000 and the camera module can be suppressed.

[0077] In the optical system 1000, the TTL can be more than 4 times of ImgH, and preferably, it can satisfy the condition of 4 < TTL / ImgH < 15 or 6 < TTL / ImgH < 11. ImgH is half of the maximum diagonal length of the effective area of the image sensor 300. In the optical system 1000, the effective focal length (EFL) is set to be greater than 10 mm, and the diagonal FOV is set to be less than 45 degrees, so that it can be set as the zoom optical system of a mobile terminal. Therefore, the optical system 1000 can provide a high-resolution and high-magnification zoom optical system including three or more lens groups. The number of lenses with an effective length greater than the maximum effective length of the image sensor 300 within the lens parts 100, 100A, and 100B is less than 50%, for example, it can be within the range of 10% to 40%. Within the lens parts 100, 100A, and 100B, the effective length of the lens closest to the object can be shorter than the effective length of the lens closest to the image sensor 300.

[0078] The optical system 1000 according to an embodiment may include an aperture stop ST. The aperture stop ST can control the amount of light incident on the optical system 1000. The aperture stop ST can be positioned between any two lenses within the lens parts 100, 100A, and 100B. Among the lenses arranged between the object and the aperture stop ST, the effective diameter of the lenses tends to become smaller from the object side toward the aperture stop ST. The aperture stop ST can be arranged on the periphery between the first lens group LG1 and the second lens group LG2. The effective lengths of the lenses arranged on the object side of the aperture stop ST and the lenses arranged on the sensor side can be less than the diagonal length of the image sensor 300. Therefore, the brightness of the optical system can be controlled. By controlling the effective diameter size of each lens, the optical system 1000 can control the incident light to compensate for the deterioration of optical characteristics caused by resolution and temperature changes, and can improve the chromatic aberration control characteristics. Here, the effective length of each lens is the average of the effective lengths of the object-side surface and the sensor-side surface along the second direction Y.

[0079] The aperture stop ST can be positioned at a set position. The aperture stop ST can be positioned around the object-side or sensor-side surface of one of the lenses of the second lens group LG2. For example, the aperture stop ST can be positioned around the object-side surface of the second lens group LG2. As another example, the aperture stop ST can be positioned around the sensor-side surface of the first lens group LG1. The aperture stop ST can be a part coated on the surface of at least one selected lens, which can be used as an aperture stop. Specifically, the object-side or sensor-side surface of one selected lens of the optical system 1000 can be used as an aperture stop for controlling the amount of light.

[0080] The optical axis distance between the aperture stop ST and the image sensor 300 is SD, and the value of SD can vary depending on the operating mode (e.g., wide-angle mode, intermediate mode, or telephoto mode).

[0081] On the optical axis OA, the first lens group LG1 and the second lens group LG2 can have a set distance DG12. The optical axis distance DG12 between the first lens group LG1 and the second lens group LG2 can be the optical axis distance between the sensor-side surface of the lens closest to the sensor in the first lens group LG1 and the object-side surface of the lens closest to the object in the second lens group LG2. The optical axis distance DG12 between the first lens group LG1 and the second lens group LG2 can be at least 0.5 mm or greater. That is, in telephoto mode, 0.5 mm ≤ DG12 can be satisfied. Here, in the lens surfaces of the first lens group LG1 and the second lens group LG2, the two surfaces facing each other can have a concave shape on the sensor side of the first lens group LG1 and a convex shape on the optical axis OA. Depending on the operating mode, the first lens group LG1 and the second lens group LG2 can refract light emitted through the sensor-side surface of the first lens group LG1 onto the object-side surface of the second lens group LG2. Alternatively, the sensor-side surface of the first lens group LG1 may have a convex shape on the optical axis OA, and the object-side surface of the second lens group LG2 may have a concave shape.

[0082] The sum of the center thicknesses of the lenses in lens portions 100, 100A, and 100B of this embodiment is ∑CT, and can be 14 mm or less, for example, in the range of 8 mm to 14 mm or 9 mm to 12 mm. The sum of the center distances between the lenses on the optical axis OA is ∑CG, and can be 8 mm or greater, for example, in the range of 8 mm to 14 mm, and can be greater than the sum of the center thicknesses of the lenses. For example, the following condition can be satisfied: ∑CT < ∑CG. If the center distance between the lenses is made greater than the center thickness of the lenses, the weight of the moving lens group can be reduced, and the increase in power consumption of the drive unit can be prevented.

[0083] The optical system 1000 or camera module may include an image sensor 300. The image sensor 300 can detect light and convert it into an electrical signal. The image sensor 300 can detect light passing sequentially through lens portions 100, 100A, and 100B. The image sensor 300 may include a device capable of detecting incident light, such as a charge-coupled device (CCD) or complementary metal-oxide-semiconductor (CMOS).

[0084] The optical system 1000 or camera module may include a filter 500. The filter 500 may be positioned between the fourth lens group LG4 and the image sensor 300. The filter 500 may be positioned between the lens closest to the sensor among the lenses of lens portions 100, 100A, and 100B and the image sensor 300. For example, the optical system 100, 100A, and 100B may be positioned between the last lens and the image sensor 300. A cover glass (not shown) is disposed between the filter 500 and the image sensor 300, protecting the upper part of the image sensor 300 and preventing a decrease in the reliability of the image sensor 300. The cover glass may be removed. The filter 500 may include an infrared filter or an infrared cutoff filter (IR cutoff). The filter 500 allows light of a set wavelength to pass through and filters light of different wavelengths. When the filter 500 includes an infrared filter, it can block radiant heat emitted from external light from being transferred to the image sensor 300. In addition, filter 500 can transmit visible light and reflect infrared light.

[0085] The optical system 1000 according to the embodiment may further include a reflective member 400 for changing the path of light, such as... Figure 29 As shown. The aforementioned reflective member 400 can be implemented as a prism or mirror that reflects incident light from the first lens group LG1 toward the lens. The optical system according to each embodiment will be described in detail below.

[0086] <First Embodiment>

[0087] Figures 1 to 9 The accompanying drawings are based on the optical system of the first embodiment. (Refer to...) Figures 1 to 5 The optical system 1000 according to the first embodiment may include multiple lens groups, such as first to fourth lens groups LG1, LG2, LG3, and LG4. The first to fourth lens groups LG1, LG2, LG3, and LG4 may include fixed-position lens groups and movable lens groups. The first lens group LG1 and the fourth lens group LG4 are lens groups with fixed positions, and the second lens group LG2 and the third lens group LG3 are lens groups with variable positions. The second lens group LG2 is disposed between the first lens group LG1 and the third lens group LG3, and the third lens group LG3 may be disposed between the second lens group LG2 and the fourth lens group LG4. The first lens group LG1 refracts incident light toward the second lens group LG2, the second lens group LG2 moves along the optical axis OA to change the zoom ratio (focal length), and the third lens group LG3 moves along the optical axis OA to adjust the focal position on the image surface of the image sensor 300.

[0088] The absolute value of the focal length of the first lens group LG1 can be greater than the absolute values ​​of the focal lengths of the second lens group LG2 and the third lens group LG3. For example, the absolute value of the focal length of the first lens group LG1 can be more than twice the focal length of the second lens group LG2. Therefore, the first lens group LG1 can disperse the incident light. The focal length difference between the second lens group LG2 and the third lens group LG3 can be 5 mm or less. The focal length of the fourth lens group LG4 can be less than the absolute value of the focal length of the first lens group LG1 and greater than the absolute value of the focal length of the third lens group LG3. The refractive power of the first lens group LG1 and the third lens group LG3 can be negative, and the refractive power of the second lens group LG2 and the fourth lens group LG4 can be positive.

[0089] Lens section 100 may include first to seventh lenses 101-107. First to seventh lenses 101-107 and image sensor 300 may be arranged sequentially along the optical axis OA of optical system 1000. The number of lenses in the first lens group LG1 may include at least two lenses for adjusting incident light quantity, power, and chromatic aberration, such as first lens 101 and second lens 102. The second lens group LG2 may include two or fewer lenses and may include a third lens 103 and a fourth lens 104; the third lens group LG3 may include a fifth lens 105 and a sixth lens 106; and the fourth lens group LG4 may include a seventh lens 107. When the focal lengths of the first to fourth lens groups LG1-LG4 are defined as FLG1, FLG2, FLG3, and FLG4, the following conditions can be satisfied.

[0090] Condition 1: FLG2 2≤│FLG1│ <FLG2 5

[0091] Condition 2: FLG2–│FLG3│ <FLG4–FLG2

[0092] Condition 3: FLG4<│FLG1│

[0093] Condition 4: FLG4 < (|FLG3| + FLG2) < |FLG1|

[0094] Since the first lens group LG1 is fixed in place, and the second lens group LG2 and the third lens group LG3 are movable along the optical axis OA, the optical system 1000 can provide various magnifications by moving the lens groups. In addition, the seventh lens 107 of the fourth lens group LG4 can control the incident angle of the principal ray to refract light parallel to the optical axis and direct it toward the image sensor 300.

[0095] The first lens 101 and the second lens 102 can correct aberrations using refractive powers with opposite signs (+, -), and the third lens 103 and the fourth lens 104 can also correct aberrations using refractive powers with opposite signs (+, -). The fifth lens 105 and the sixth lens 106 can also correct aberrations using refractive powers with opposite signs (+, -). According to the operating mode described below, the center distance between the first lens 101 and the second lens 102 can be a fixed distance. For example, the center distance between the first lens 101 and the second lens 102 can remain unchanged regardless of the operating mode and can be constant. Here, the center distance between the lenses can represent the optical axis distance between adjacent lenses.

[0096] The third lens 103 and the fourth lens 104 may have a set distance. Specifically, the center distance between adjacent lenses 104 and 105 may be a fixed distance, depending on the operating mode described below. The fifth lens 105 and the sixth lens 106 may have a set distance. Specifically, the center distance between the fifth lens 105 and the sixth lens 106 may remain constant and unchanged even when the operating mode described below changes. The optical axis distance (BFL) between the seventh lens 107 and the image sensor 300 may remain constant and not change according to the operating mode. The seventh lens 107 has a set distance from the image sensor 300 and / or the filter 500, and may have a fixed distance that does not change according to the operating mode.

[0097] The first lens 101 may have a positive (+) refractive power along the optical axis OA. The first lens 101 may comprise a plastic or glass material, and may be, for example, a plastic material. The first lens 101 may comprise a first surface S1 on the object side and a second surface S2 on the sensor side. The first surface S1 may have a convex shape along the optical axis OA, and the second surface S2 may also have a convex shape. That is, the first lens 101 may have a shape that convexes on both sides along the optical axis OA. Alternatively, the first lens 101 may have a meniscus shape convex toward the object. Alternatively, the first surface S1 may have a concave shape, and the second surface S2 may have a convex shape. At least one or both of the first surface S1 and the second surface S2 may be aspherical, and the conic constant K and the aspherical coefficients A to I of orders 4 to 20 of the first surface S1 and the second surface S2 may be determined by… Figure 5 L1S1 and L1S2 are represented in the figure.

[0098] The maximum effective length of the first lens 101 can be the second largest among the lenses. That is, the effective length of the first surface S1 of the first lens 101 along the principal axis or the second direction Y can be greater than the average of the effective lengths of the object-side surfaces and sensor-side surfaces of the second to sixth lenses 102 to 106. Therefore, the first lens 101 can improve optical aberrations or control incident light. The first surface S1 and the second surface S2 can be configured so that there are no critical points from the optical axis to the end of the effective region.

[0099] The second lens 102 may have a positive (+) or negative (-) refractive power on the optical axis OA, for example, a negative refractive power. The second lens 102 may comprise a plastic or glass material, for example, a plastic material. The second lens 102 may comprise a third surface S3 on the object side and a fourth surface S4 on the sensor side, and the third surface S3 on the optical axis may have a concave shape, and the fourth surface S4 may also have a concave shape. The second lens 102 may have a shape with both sides concave. Alternatively, the second lens 102 may have a meniscus shape convex toward the object. Alternatively, the third surface S3 may have a convex shape, and the fourth surface S4 may also have a convex shape. Alternatively, the third surface S3 may have a concave shape, and the fourth surface S4 may have a convex shape. At least one or both of the third surface S3 and the fourth surface S4 of the second lens 102 may be aspherical, and the conic constant K and the aspherical coefficients A to I may be determined by… Figure 5 L2S1 and L2S2 are represented in the diagram. The third surface S3 and the fourth surface S4 can be configured such that there are no critical points from the optical axis to the end of the effective region.

[0100] The third lens 103 may have the same refractive power sign as the first lens 101 along the optical axis OA. That is, the third lens 103 may have positive refractive power. The third lens 103 may include a plastic or glass material, for example, a plastic material. The third lens 103 may include a fifth surface S5 on the object side and a sixth surface S6 on the sensor side. On the optical axis OA, the fifth surface S5 may have a convex shape, and the sixth surface S6 may have a convex shape. The third lens 103 may have a shape that is convex on both sides. Alternatively, the fifth surface S5 may have a convex shape, and the sixth surface S6 may have a concave shape. At least one or both of the fifth surface S5 and the sixth surface S6 of the third lens 103 may be aspherical. The conic constant K and the aspherical coefficients A to I of the fifth surface S5 and the sixth surface S6 may be determined by... Figure 5 L3S1 and L3S2 are represented in the diagram. The fifth surface S5 and the sixth surface S6 can be configured such that there is no critical point from the optical axis to the end of the effective region, or the sixth surface S6 can have a critical point at the edge.

[0101] The second lens 102 can compensate for chromatic aberration occurring in the first lens 101. The refractive index of the first lens 101 is arranged to be greater than that of the second lens 102, thereby dispersing the incident light. Therefore, the first lens group LG1 controls the dispersion of light supplied to the second lens group LG2, thereby suppressing an increase in the lens size of the second lens group LG2. The radius of curvature of the fourth surface S4 of the second lens 102 can be adjusted to change the center distance DG12 between the first lens group LG1 and the second lens group LG2 according to the operating mode.

[0102] The fourth lens 104 may have a negative (+) refractive power along the optical axis OA. The fourth lens 104 may comprise a plastic or glass material, for example, a plastic material, and may have a refractive index less than 1.6. The fourth lens 104 includes a seventh surface S7 on the object side and an eighth surface S8 on the sensor side, wherein both the seventh surface S7 and the eighth surface S8 have a convex shape along the optical axis. That is, the fourth lens 104 may have a shape that is convex on both sides along the optical axis OA. Alternatively, the seventh surface S7 may be convex along the optical axis OA, and the eighth surface S8 may be concave along the optical axis OA. At least one or both of the seventh surface S7 and the eighth surface S8 of the fourth lens 104 may be aspherical. The conic constant K and aspherical coefficients A~I of the seventh surface S7 and the eighth surface S8 may be determined by… Figure 5 L4S1 and L4S2 are represented in the diagram. The seventh surface S7 and the eighth surface S8 can be configured such that there are no critical points from the optical axis to the end of the effective region.

[0103] The third lens 103 can have a convex shape on both sides, and the fourth lens 104 can have a concave shape on both sides. The center thickness CT3 of the third lens 103 can be thicker than the edge thickness. The center thickness of the fourth lens 104 can be thinner than the edge thickness. Therefore, the distance between the sixth surface S8 and the seventh surface S9 can be reduced by the convex sixth surface S8 of the third lens 103 and the concave seventh surface S7 of the fourth lens 104. The Abbe number Vd3 of the third lens 103 can be greater than the Abbe numbers of the first lens 101, the second lens 102, the fourth lens 104, and the fifth lens 105. The difference in Abbe number between the third lens 103 and the fourth lens 104 can be greater than 20 or greater than 25. Therefore, the second lens group LG2 can minimize the chromatic aberration caused by positional changes with the operating mode.

[0104] The fifth lens 105 may have a positive (+) or negative (-) refractive power on the optical axis OA. The fifth lens 105 has a positive refractive power and may have a refractive power sign opposite to that of the fourth lens 104. The fifth lens 105 may comprise a plastic or glass material, and may be, for example, a plastic material. The fifth lens 105 may comprise a ninth surface S9 on the object side and a tenth surface S10 on the sensor side. The ninth surface S9 may have a concave shape on the optical axis OA, and the tenth surface S10 may have a convex shape. That is, the fifth lens 105 may have a meniscus shape convex toward the sensor side on the optical axis OA. Alternatively, the fifth lens 105 may have a shape that is concave on both sides. Alternatively, the fifth lens 105 may have a convex shape toward the object. At least one or both of the ninth surface S9 and the tenth surface S10 may be aspherical. The conic constant K and aspherical coefficients A to I of the ninth surface S9 and the tenth surface S10 may be determined by… Figure 5 L5S1 and L5S2 are represented in the text. The ninth surface S9 and the tenth surface S10 of the fifth lens 105 can be configured such that there are no critical points from the optical axis to the end of the effective region.

[0105] The sixth lens 106 may have a positive (+) or negative (-) refractive power on the optical axis OA; for example, it may have a negative refractive power. The sixth lens 106 may comprise a plastic or glass material; for example, it may be a plastic material. The sixth lens 106 may comprise an eleventh surface S11 on the object side and a twelfth surface S12 on the sensor side. The eleventh surface S11 may have a concave shape on the optical axis OA, and the twelfth surface S12 may have a convex shape. That is, the sixth lens 106 may have a meniscus shape convex toward the sensor side on the optical axis OA. Alternatively, the eleventh surface S11 may have a convex shape on the optical axis OA, and the twelfth surface S12 may have a convex shape on the optical axis OA. Alternatively, the eleventh surface S11 may have a concave shape on the optical axis OA, and the twelfth surface S12 may have a concave shape on the optical axis OA. Alternatively, the eleventh surface S11 may have a convex shape on the optical axis OA, and the twelfth surface S12 may have a concave shape on the optical axis OA. At least one or both of the eleventh surface S11 and the twelfth surface S12 of the sixth lens 106 may be aspherical. The aspherical coefficients A~I and the conic constant K of the eleventh surface S11 and the twelfth surface S12 can be determined by… Figure 5 L6S1 and L6S2 are represented in the text. The eleventh surface S11 and the twelfth surface S12 can be configured such that there are no critical points from the optical axis to the end of the effective region.

[0106] The seventh lens 107 may have a positive (+) or negative (-) refractive power on the optical axis OA, and may have a positive refractive power. The refractive power of the seventh lens 107 has an opposite sign to that of the sixth lens 106, thereby improving chromatic aberration. The seventh lens 107 may comprise a plastic or glass material, and may be, for example, a plastic material. The seventh lens 107 may comprise a thirteenth surface S13 on the object side and a fourteenth surface S14 on the sensor side. The thirteenth surface S13 may have a convex shape on the optical axis OA, and the fourteenth surface S14 may also have a convex shape. That is, the seventh lens 107 may also have a shape that is convex on both sides of the optical axis OA. As another example, the thirteenth surface S13 may have a concave shape, and the fourteenth surface S14 may have a convex shape. Alternatively, the thirteenth surface S13 may have a concave shape, and the fourteenth surface S14 may have a concave shape along the optical axis OA. Alternatively, the thirteenth surface S13 may have a convex shape, and the fourteenth surface S14 may have a concave shape.

[0107] At least one or both of the thirteenth surface S13 and the fourteenth surface S12 of the seventh lens 107 may be aspherical. The aspherical coefficients A~I and the conic constant K of the thirteenth surface S13 and the fourteenth surface S14 can be determined by… Figure 5 L7S1 and L7S2 are represented in the diagram. The thirteenth surface S13 and the fourteenth surface S14 can be configured to have no critical point from the optical axis to the end of the effective region. As another example, the thirteenth surface S13 and / or the fourteenth surface S14 of the seventh lens 107 may have a critical point between the optical axis and the end of the effective region, and the critical point is the point where the trend of the sag value changes. That is, the critical point is the point on the lens surface where the sag value first increases and then decreases, or where the sag value first decreases and then increases. The sag value is the distance between the optical axis and the lens surface of a straight line perpendicular to the center of each lens surface, and the sag value has a positive value at the sensor-side position relative to the center of each lens surface and a negative value at the object-side position relative to the center of each lens surface. The absolute difference in the radius of curvature between the object-side surface and the sensor-side surface of the third to seventh lenses 103 and 104, and 105 and 106, can be 10 mm or less, for example, 6 mm or less. By subtly setting the radius of curvature between the object-side and sensor-side surfaces of these movable lenses, changes in the optical path can be predicted, and increases in lens size can be suppressed. Furthermore, the absolute difference in the radius of curvature between the object-side and sensor-side surfaces of the first lens 101 is the largest to allow for the dispersion of incident light. Conversely, the difference in the radius of curvature between the object-side and sensor-side surfaces of the last lens 107 is the smallest to allow for the refraction of light parallel to the entire area of ​​the image sensor 300.

[0108] The sixth lens 106 and the seventh lens 107 have refractive powers with opposite signs, and the difference in their Abbe numbers can be greater than 20, for example, greater than 30. In this case, chromatic aberration can be controlled. Therefore, the third lens group LG3 can minimize the chromatic aberration variation caused by the position changing with the mode and perform an achromatic function. By setting the difference between the absolute value of the radius of curvature of the thirteenth surface S13 and the absolute value of the radius of curvature of the fourteenth surface S14 to be sufficiently small as 1.5 mm or less, the seventh lens 107 can refract incident light parallel to the surface of the image sensor 300. The effective length of the seventh lens 107 is set to be longer than the effective length of the sixth lens 106, so that the incident light can be refracted to the periphery of the image sensor 300.

[0109] At least one of the first lens 101 and the seventh lens 107 may have a non-circular shape, wherein the effective lengths along the first direction X and the second direction Y are different from each other. The fourth lens group LG4 can control the principal ray angle (CRA). Specifically, the CRA of the optical system 1000 according to the embodiment may be less than about 20 degrees, and the seventh lens 107 of the fourth lens group LG4 can correct the CRA of the light incident on the image sensor 300 according to each operating mode.

[0110] The camera module can move along the optical axis OA toward an object or sensor, including at least one or all of the second lens group LG2 and the third lens group LG3 among the multiple lens groups LG1, LG2, LG3 and LG4 in the optical system 1000. For example... Figure 29 As shown, the camera module may include drive members DM1 and DM2 connected to the optical system 1000. Drive members DM1 and DM2 include at least one or more first drive members DM1 disposed outside the second lens group LG2 and at least one or more second drive members DM2 disposed outside the third lens group LG3, and can move along the optical axis OA according to the operating mode. The operating mode may include, for example... Figure 2 The first mode shown performs movement at a first multiplier, and as shown in the example. Figure 3 The diagram shows a third mode that performs movement at a second magnification rate, different from the first magnification rate. In this case, the second magnification rate can be greater than the first magnification rate. Furthermore, the operating mode can include a second mode that has a magnification rate between the first and third modes, such as... Figure 1 As shown. Here, the first magnification can be the lowest magnification of the optical system 1000, and the second magnification can be the highest magnification of the optical system 1000. The first mode can be a wide-angle mode, the second mode can be an intermediate mode, and the third mode can be a telephoto mode.

[0111] like Figure 29As shown, drive members DM1 and DM2 can move M1 and M2 of each lens group in the second lens group LG2 and the third lens group LG3 according to an operating mode selected from the first to the third modes, or operate them in an initial mode. Specifically, each of the plurality of drive members DM1 and DM2 is connected to the second lens group LG2 and the third lens group LG3, and can move each of the second lens group LG2 and the third lens group LG3 according to the operating mode. The initial mode can be any of the first, second, and third modes, for example, the second mode or an intermediate mode. For example, in the first mode, each of the second lens group LG2 and the third lens group LG3 can be positioned at a position defined as a first position (position 1). In the second mode, each of the second lens group LG2 and the third lens group LG3 can be positioned at a position defined as a second position (position 2), which is closer to the object than the first position. In the third mode, each of the second lens group LG2 and the third lens group LG3 can be positioned at a position defined as a third position (position 3), which is closer to the sensor than the first position. The first position can be the region between the second and third positions.

[0112] The first position of the second lens group LG2 in the first mode can be the area between the second and third positions of the second lens group LG2 in the second and third modes. The first position of the third lens group LG3 in the first mode can be the area between the second and third positions of the third lens group LG3 in the second and third modes. Depending on the operating mode, at least one of the second lens group LG2 and the third lens group LG3 can move along the optical axis, and the first lens group LG1 and the fourth lens group LG4 can be arranged in a fixed position. Depending on the operating mode, the second lens group LG2 can move M1, and the first lens group LG1 and the fourth lens group LG4 can be arranged in a fixed position. Depending on the operating mode, the third lens group LG3 can move M1, and the first lens group LG1 and the fourth lens group LG4 can be arranged in a fixed position. In each of the first, second, and third positions according to the operating mode, the first to fourth lens groups LG1, LG2, LG3, and LG4 can have a predetermined distance from adjacent lens groups. Therefore, the optical system 1000 can have a constant TTL (Total Track Length) and BFL depending on the operating mode, and the effective focal length and magnification of the optical system 1000 can be controlled by controlling the position of some lens groups. For ease of illustration, the center thickness of each of the first to seventh lenses 101 to 107 is CT1-CT7, the Abbe number is Vd1-Vd7, the refractive index is Nd1-Nd7, and the average value or maximum effective length in the second direction Y can be defined as CA1-CA7.

[0113] The effective length CA1 of the first lens 101 is the second longest among the lenses, and the effective length CA5 of the fifth lens 105 is the shortest. The effective length CA1 of the first lens 101 can be 5 mm or greater. The effective lengths CA5 and CA6 of the fifth lens 105 and the sixth lens 106 can be less than 5 mm. The absolute difference in the radius of curvature between the thirteenth surface S13 and the fourteenth surface S14 of the seventh lens 107 can be the smallest among the differences in the absolute value of the radius of curvature between the object-side surface and the sensor-side surface of each lens, and can be, for example, 1.5 mm or less or 1 mm or less. The absolute difference in the radius of curvature between the eleventh surface S11 and the twelfth surface S12 of the sixth lens 106 can be 3 mm or less, for example, in the range of 1.5 mm to 3 mm. Since the center thickness CT6 of the sixth lens 106 is less than 2 mm and the difference in the absolute value of the radius of curvature on both sides is small, light can be guided to the seventh lens 107 without causing a significant change in the incident light path.

[0114] In terms of absolute focal length, the focal length F5 of the fifth lens 105 can be the largest among the lenses, and the absolute difference in focal length between two adjacent lenses can be the largest between the fifth lens 105 and the sixth lens 106, while the absolute difference in focal length between the second lens 102 and the third lens 103 can be the smallest. The focal lengths of the first to seventh lenses 101 to 107 can be defined as F1-F7, and can satisfy the following conditions.

[0115] Condition 1: |F2| <F1<│F2│ 3

[0116] Condition 2: 0<(│F2│–F3)≤(│F4│-F3)<6 mm

[0117] Condition 3: |F6| <F7<F5

[0118] Condition 4: (│F2│+F3+│F4│) <F5

[0119] At least one of the center thicknesses CT3, CT4, and CT5 of the third, fourth, and fifth lenses 103, 104, and 105 can be the thickest among the center thicknesses of the lenses, for example, 2 mm or more, and the center thickness CT5 of the fifth lens 105 can be the largest. At least one of the center thicknesses CT2 and CT6 of the second lens 102 and the sixth lens 106 can be the thinnest among the center thicknesses of the lenses, thereby adjusting the light path according to the positional movement of the second lens group LG2 and the third lens group LG3. The radii of curvature of the first to fourth surfaces S1, S2, S3, and S4 of the first lens 101 and the second lens 102 can be set to 5 mm or more, so as not to significantly cause a change in the angle of refraction of the incident light, and the light can be guided through the third lens 103 to the fourth lens 104.

[0120] The center thicknesses CT3 and CT4 of the third lens 103 and the fourth lens 104 of the second lens group LG2 can each be greater than the sum of the center thicknesses CT1 and CT2 of the first lens 101 and the second lens 102. The sum of the center thicknesses CT3 and CT4 of the third lens 103 and the fourth lens 104 of the second lens group LG2 can also be greater than the sum of the center thicknesses CT6 and CT7 of the sixth lens 106 and the seventh lens 107. Therefore, the second lens group LG2 can guide light incident through the first lens group LG1 to the effective area of ​​the third lens group LG3.

[0121] The optical axis distance between the first lens group LG1 and the second lens group LG2 is DG12, the optical axis distance between the second lens group LG2 and the third lens group LG3 is DG23, and the optical axis distance between the third lens group LG3 and the fourth lens group LG4 is DG34. Each of these can be at least 0.5 mm or greater, and at most 8 mm or less, depending on the magnification variation of the operating mode. Specifically, the optical axis distance DG12 between the first lens group LG1 and the second lens group LG2 can be 0.5 mm or greater, for example, in the range of 0.5 mm to 7 mm. The optical axis distance DG23 between the second lens group LG2 and the third lens group LG3 can be 1 mm or greater, for example, in the range of 1 mm to 3 mm. The optical axis distance DG34 between the third lens group LG3 and the fourth lens group LG4 can be 0.8 mm or greater, for example, in the range of 0.8 mm to 8 mm.

[0122] The relationship between DG12, DG23, and DG34 in the first, second, and third modes is as follows: First mode (wide angle): DG34 <DG23<DG12 Second Mode (Middle): DG23 <DG12<DG34 Third mode (telephoto): DG12 < DG23 < DG34 In the first mode, DG12 and DG23, in the second mode, DG12 and DG34, and in the third mode, DG23 and DG34 can be greater than BFL. Here, BFL is the optical axis distance from the sensor-side surface of the fourth lens group LG4 or the seventh lens 107 to the surface of the image sensor 300.

[0123] In the first, second, and third modes, the maximum moving distance of the second lens group LG2 and the third lens group LG3 is Max_mMd13, and it can satisfy: Max_mMd13 < 5.7 mm, preferably, 4 mm < Max_mMd13 ≤ 5.5 mm. Thus, the maximum moving distance for the zoom ratio can be reduced, thereby reducing the power consumption of the driving member.

[0124] Depending on the operation mode, the F-number of the optical system 1000 provides a brightness of 5 or less, and the range of the F-number can be from 2.2 to 5. The aperture can be positioned between the first lens group LG1 and the second lens group LG2, and can be arranged, for example, around the fifth surface S5 of the third lens 103.

[0125] Table 1 and Figure 4 are items of the above mathematical expressions in the optical system 1000 of the first embodiment, including TTL (mm), BFL (back focal length), effective focal length F (mm), the focal length of each lens group, ImgH (mm), effective length (mm), the center thickness (CT) of each lens, the center distance (CG) between two adjacent lenses, TD (mm) (which is the optical axis distance from the first surface S1 to the fourteenth surface S14), the focal lengths F1, F2, F3, F4, F5, F6, and F7 (mm) of each of the first to seventh lenses, diagonal FOV (degrees), F-number, etc.

[0126]

Table 1

[0127] Table 2 can represent the effective focal length F, FOV, F-number, entrance pupil diameter (EPD), SD, and the center distances DG12, DG23, and DG34 between adjacent lens groups in the optical system according to the first to third modes of the first embodiment. SD is the optical axis distance from the position of the aperture to the image sensor.

[0128]

Table 2

[0129] As Figure 6As shown, the optical system according to the first embodiment can have MTF characteristics according to the first, second, and third modes (wide-angle, intermediate, and telephoto modes). Specifically, Figure 6 The graphs show the diffraction MTF characteristics of the optical system 1000 operating in the first to third modes, and it can be seen that the defocus position does not change significantly depending on the operating mode.

[0130] Figures 7 to 9 This is a graph measuring the spherical aberration (longitudinal spherical aberration), astigmatism, and distortion from left to right in the aberration curve diagram of the optical system according to the first embodiment. Figures 7 to 9 In the graph, the X-axis represents focal length (mm) and distortion (%), while the Y-axis represents image height. Furthermore, the spherical aberration graph is for light in the approximately 435 nm, 486 nm, 546 nm, 587 nm, and 656 nm wavelength range, while the astigmatism and distortion graphs are for light in the 546 nm wavelength range. In the aberration graph, the closer each curve is to the Y-axis, the better the aberration correction. It can also be seen that the aberration changes little depending on the operating mode (wide-angle, intermediate, telephoto).

[0131] <Second Embodiment>

[0132] Figures 10 to 18 This is an accompanying drawing illustrating an optical system and camera module according to a second embodiment. When describing the configuration of the second embodiment, configurations identical to those of the first embodiment may include the configuration and description of the first embodiment. (Refer to...) Figures 10 to 14 The optical system 1000 according to the second embodiment may include a lens portion 100A having first to fourth lens groups LG1, LG2, LG3 and LG4. The first lens group LG1 and the fourth lens group LG4 are lens groups with fixed positions, and the second lens group LG2 and the third lens group LG3 are lens groups with variable positions.

[0133] The absolute value of the focal length of the first lens group LG1 can be greater than the absolute value of the focal lengths of the second lens group LG2, the third lens group LG3, and the fourth lens group LG4. For example, the absolute value of the focal length of the first lens group LG1 can be at least twice the focal length of the second lens group LG2. The focal length of the second lens group LG2 can be less than the focal length of the fourth lens group LG4. The focal length of the fourth lens group LG4 can be greater than the absolute value of the focal length of the third lens group LG3. The absolute value of the focal length difference between the second lens group LG2 and the third lens group LG3 can be 5 mm or less. The first lens group LG1 and the third lens group LG3 can have negative refractive power on the optical axis, and the second lens group LG2 and the fourth lens group LG4 can have positive refractive power on the optical axis.

[0134] Lens section 100A may include first to seventh lenses 111 to 117. The first to seventh lenses 111 to 117 and the image sensor 300 may be arranged sequentially along the optical axis OA of the optical system 1000. First lens group LG1 may include first lens 111 and second lens 112. Second lens group LG2 may include third lens 113 and fourth lens 114. Third lens group LG3 may include fifth lens 115 and sixth lens 116. Fourth lens group LG4 may include seventh lens 117.

[0135] The focal lengths of the first to fourth lens groups, LG1 to LG4, can satisfy the following conditions: Condition 1: FLG2 2≤│FLG1│ <FLG2 5 Condition 2: FLG2–│FLG3│ <FLG4–FLG2 Condition 3: FLG4<│FLG1│ Condition 4: FLG4 < (|FLG3| + FLG2) < |FLG1| Since the first lens group LG1 and the fourth lens group LG4 are fixed in place, and the second lens group LG2 and the third lens group LG3 can move in the direction of the optical axis OA, the optical system 1000 can provide various magnifications by moving the lens groups. The seventh lens 117 can control the incident angle of the principal ray and refract the principal ray so that light parallel to the optical axis is incident on the image sensor 300.

[0136] The first lens 111 and the second lens 112 can correct aberrations by having refractive powers with opposite signs (+, -), and the third lens 113 and the fourth lens 114 can also correct aberrations by having refractive powers with opposite signs (+, -). The fifth lens 115 and the sixth lens 116 can also correct aberrations by having refractive powers with opposite signs (+, -). The first lens 111, the second lens 112, the fifth lens 115, and the seventh lens 117 can have positive (+) refractive power on the optical axis OA. The second lens 112, the fourth lens 114, and the sixth lens 116 can have negative (-) refractive power on the optical axis OA. The materials of the first to sixth lenses 111 to 116 can be different from the material of the seventh lens 117. The first to sixth lenses 111 to 116 can have aspherical shapes, and the seventh lens 117 can have spherical shapes. The first to sixth lenses 111 to 116 can be made of plastic, and the seventh lens 117 can be made of glass.

[0137] On the optical axis, the first surface S1 of the first lens 111 may have a convex shape, and the second surface S2 may have a concave shape. The radius of curvature of the second surface S2 on the optical axis may be greater than the radius of curvature of the first surface S1, for example, more than 10 times or 20 times greater. Furthermore, the average value of the radii of curvature of the first surface S1 and the second surface S2 of the first lens 111 may be greater than the average value of the absolute values ​​of the radii of curvature of the lenses. The maximum effective length of the first lens 111 may be the second largest among lenses. The effective length of the first surface S1 of the first lens 111 may be greater than the average value of the effective lengths of the object-side surfaces and sensor-side surfaces of the second to sixth lenses 112 to 116. The maximum effective length of the first lens 111 may be the largest among plastic lenses. The second surface S2 of the first lens 111 may have at least one critical point in the region extending from the optical axis to the end of the effective region.

[0138] The third surface S3 of the second lens 112 may be concave along the optical axis, and the fourth surface S4 may also be concave. The absolute value of the radius of curvature of the third surface S3 along the optical axis may be greater than the radius of curvature of the fourth surface S4. The difference (absolute value) between the radii of curvature of the third surface S3 and the fourth surface S4 may be 6 mm or less. Along the optical axis OA, the fifth surface S5 of the third lens 114 may be convex, and the sixth surface S6 may also be convex. The seventh surface S7 of the fourth lens 114 may be concave, and the eighth surface S8 may also be concave. Along the optical axis OA, the ninth surface S9 of the fifth lens 115 may be concave, and the tenth surface S10 may be convex. Along the optical axis OA, the eleventh surface S11 of the sixth lens 116 may be concave, and the twelfth surface S12 may also be concave. The first to twelfth surfaces S1 to S12 are aspherical, and the conic constant K and the aspherical coefficients A to I of orders 4 to 20 can be obtained as follows: Figure 14 The representation shown.

[0139] On the optical axis OA, the thirteenth surface S13 of the seventh lens 117 can have a convex shape, and the fourteenth surface S14 can also have a convex shape. The seventh lens 117 has a shape that is convex on both sides and can refract incident light into parallel light toward the image sensor 300. The thirteenth surface S13 and the fourteenth surface S14 of the seventh lens 117 are spherical, and the average of the absolute values ​​of the radii of curvature of the thirteenth surface S13 and the fourteenth surface S14 can be the second largest.

[0140] The absolute difference in the radius of curvature between the object-side surface and the sensor-side surface of the third to sixth lenses 113, 114, 115, and 116 can be 10 mm or less. Since the difference in the radius of curvature between the object-side surface and the sensor-side surface of these movable lenses is not set to be large, changes in the optical path can be predicted, and an increase in lens size can be suppressed. Furthermore, the first lens 111 has the largest absolute difference in the radius of curvature between its object-side surface and the sensor-side surface, thereby increasing the amount of incident light and refracting it into the effective area of ​​the second lens 112. The refractive index of the seventh lens 117 can be the highest among the lenses. Furthermore, the absolute difference in the focal length of the first to seventh lenses 111 to 117 can be 17 mm or less.

[0141] The effective length CA1 of the first lens 111 is the second longest among the lenses, and the effective length CA5 of the fifth lens 115 is the shortest. The effective length CA1 of the first lens 111 can be 5 mm or greater. The effective lengths CA5 and CA6 of the fifth lens 115 and the sixth lens 116 can be less than 5 mm. The center thickness CT6 of the sixth lens 116 is less than 2 mm, and the difference in the absolute value of the radii of curvature on both sides is set to be small, so that light can be guided to the seventh lens 117 without significantly changing the path of the incident light.

[0142] In terms of absolute focal length, the focal length F5 of the fifth lens 115 can be the largest among the lenses. Furthermore, between two adjacent lenses, the absolute difference in focal length between the fifth lens 115 and the sixth lens 116 can be the largest, and the absolute difference in focal length between the second lens 112 and the third lens 113 can be the smallest. The focal lengths of the first to seventh lenses 111 to 117 can satisfy the following conditions.

[0143] Condition 1: |F2| <F1<│F2│ 3

[0144] Condition 2: 0 < (|F2|–F3) ≤ (|F4|-F3) < 6mm

[0145] Condition 3: |F6| <F7<F5

[0146] Condition 4: (│F2│+F3+│F6│) <F5

[0147] At least one of the center thicknesses CT3 and CT5 of the third lens 113 and the fifth lens 115 can be the thickest among the center thicknesses of the lenses, for example, 2 mm or greater, and the center thickness CT5 of the fifth lens 115 can be the largest. At least one of the center thicknesses CT2 and CT6 of the second lens 112 and the sixth lens 116 can be the thinnest among the center thicknesses of the lenses, thereby allowing adjustment of the optical path according to the positional movement of the second lens group LG2 and the third lens group LG3.

[0148] The center thicknesses CT3 and CT4 of the third lens 113 and the fourth lens 114 of the second lens group LG2 can both be greater than the sum of the center thicknesses CT1 and CT2 of the first lens 111 and the second lens 112. The sum of the center thicknesses CT3 and CT4 of the third lens 113 and the fourth lens 114 of the second lens group LG2 can be greater than the sum of the center thicknesses CT6 and CT7 of the sixth lens 116 and the seventh lens 117. Therefore, the second lens group LG2 can guide the light incident through the first lens group LG1 to the effective area of the third lens group LG3.

[0149] Depending on the change in magnification in the operating mode, the optical axis distances DG12 between the first lens group LG1 and the second lens group LG2, DG23 between the second lens group LG2 and the third lens group LG3, and DG34 between the third lens group LG3 and the fourth lens group LG4 can all be at least 0.5 mm and at most 8 mm. Specifically, the optical axis distance DG12 between the first lens group LG1 and the second lens group LG2 can be at least 0.5 mm, for example, within the range of 0.5 mm to 7 mm. The optical axis distance DG23 between the second lens group LG2 and the third lens group LG3 can be at least 1 mm, for example, within the range of 1 mm to 3 mm. The optical axis distance DG34 between the third lens group LG3 and the fourth lens group LG4 can be 0.8 mm or greater, for example, within the range of 0.8 mm to 8 mm. In the first mode, DG12 and DG23, in the second mode, DG12, DG23, and DG34, and in the third mode, DG23 and DG34, can be greater than the BFL. The maximum movement distance Max_mMd13 of the second lens group LG2 and the third lens group LG3 in the first mode, the second mode, and the third mode can satisfy: 4 mm < Max_mMd13 ≤ 5.5 mm. Therefore, the maximum movement distance for zooming can be reduced, thereby reducing the power consumption of the driving member.

[0150] Depending on the operating mode, the optical system 1000 provides a brightness of 5 or less by an F-number, and the F-number can be in the range of 2.2 to 5. The aperture stop can be positioned between the first lens group LG1 and the second lens group LG2, and can be arranged, for example, around the fifth surface S5 of the third lens 113.

[0151] Table 3 and Figure 13 The items in the above mathematical expression used in the optical system 1000 of the second embodiment include TTL (mm), BFL, effective focal length F (mm), focal length of each lens group, ImgH (mm), effective length (mm), center thickness of each lens (CT), center distance between two adjacent lenses (CG), TD (mm) (which is the optical axis distance from the first surface S1 to the fourteenth surface S14), focal lengths F1, F2, F3, F4, F5, F6 and F7 (mm) of each of the first to seventh lenses, diagonal FOV (degrees), F number, etc.

[0152] Table 3

[0153] Table 4 can represent the effective focal length F, FOV, F-number, entrance pupil diameter (EPD), SD, and center distances DG12, DG23, and DG34 between adjacent lens groups in the optical system according to the first to third modes according to the second embodiment. SD is the distance from the aperture position to the optical axis of the image sensor.

[0154] Table 4

[0155] like Figure 15 As shown, the optical system according to the second embodiment can have MTF characteristics according to the first, second, and third modes (wide-angle, intermediate, and telephoto modes). In detail, Figure 15 The graphs show the diffraction MTF characteristics of the optical system 1000 operating in the first to third modes, and it can be seen that the defocus position does not change much depending on the operating mode. Figures 16 to 18 This is a graph showing the spherical aberration (longitudinal spherical aberration), astigmatism, and distortion curves from left to right in the aberration curve diagram of the optical system according to the second embodiment. Figures 16 to 18In the graph, the X-axis represents focal length (mm) and distortion (%), while the Y-axis represents the image height. Furthermore, the spherical aberration graph is for light in the approximately 435 nm, 486 nm, 546 nm, 587 nm, and 656 nm wavelengths, while the astigmatism and distortion graphs are for light in the 546 nm wavelength band. In the aberration graph, the closer each curve is to the Y-axis, the better the aberration correction. It can also be seen that the aberration changes little depending on the operating mode (wide-angle, intermediate, telephoto).

[0156] <Third Embodiment>

[0157] Figures 19 to 27 This is an accompanying drawing illustrating an optical system according to a third embodiment and a camera module including the optical system. When describing the configuration according to the third embodiment, configurations identical to those of the first embodiment may include the configuration and description of the first embodiment. (Refer to...) Figures 19 to 23 The optical system 1000 according to the third embodiment may include a lens portion 100B having a first lens group LG1, a second lens group LG2, a third lens group LG3, and a fourth lens group LG4. The first lens group LG1 and the fourth lens group LG4 are lens groups with fixed positions, and the second lens group LG2 and the third lens group LG3 are lens groups with variable positions.

[0158] The absolute value of the focal length of the first lens group LG1 can be greater than the absolute value of the focal lengths of the second lens group LG2, the third lens group LG3, and the fourth lens group LG4. For example, the absolute value of the focal length of the first lens group LG1 can be greater than twice the focal length of the second lens group LG2. The focal length of the second lens group LG2 can be less than the focal length of the fourth lens group LG4 and greater than the absolute value of the focal length of the third lens group LG3. The focal length of the fourth lens group LG4 can be greater than the absolute value of the focal length of the third lens group LG3. The absolute value of the focal length difference between the second lens group LG2 and the third lens group LG3 can be 5 mm or less. The first lens group LG1 and the third lens group LG3 can have negative refractive power on the optical axis, and the second lens group LG2 and the fourth lens group LG4 can have positive refractive power on the optical axis.

[0159] Lens section 100B may include first to seventh lenses 121 to 127. The first to seventh lenses 121 to 127 and the image sensor 300 may be arranged sequentially along the optical axis OA of the optical system 1000. First lens group LG1 may include first lens 121 and second lens 122. Second lens group LG2 may include third lens 123 and fourth lens 124. Third lens group LG3 may include fifth lens 125 and sixth lens 126. Fourth lens group LG4 may include seventh lens 127.

[0160] The focal lengths of the first to fourth lens groups, LG1 to LG4, can satisfy the following conditions: Condition 1: FLG2 2≤│FLG1│ <FLG2 5 Condition 2: FLG2–│FLG3│ <FLG4–FLG2 Condition 3: FLG4<│FLG1│ Condition 4: FLG4 < (|FLG3| + FLG2) < |FLG1| Since the first lens group LG1 and the fourth lens group LG4 are fixed in place, and the second lens group LG2 and the third lens group LG3 can move along the optical axis OA, the optical system 1000 can provide various magnifications by moving the lens groups. The seventh lens 127 can control the incident angle of the principal ray and refract the principal ray so that light parallel to the optical axis is incident on the image sensor 300.

[0161] The first lens 121 and the second lens 122 can correct aberrations with refractive powers of opposite signs (+, -), and the third lens 123 and the fourth lens 124 can also correct aberrations with refractive powers of opposite signs (+, -). The fifth lens 125 and the sixth lens 126 can also correct aberrations with refractive powers of opposite signs (+, -). The first lens 121, the second lens 122, the fifth lens 125, and the seventh lens 127 can have positive (+) refractive power on the optical axis OA. The second lens 122, the fourth lens 124, and the sixth lens 126 can have negative (-) refractive power on the optical axis OA.

[0162] The material of the first lens 127 may be different from that of the second to seventh lenses 122 to 127. The second to seventh lenses 127 may have an aspherical shape, while the first lens 121 may have a spherical shape. The second to seventh lenses 122 to 127 may be made of plastic, and the first lens 121 may be made of glass. Because the first lens 121 is set to a spherical shape made of glass, optical property degradation due to heat can be prevented, and surface damage can be suppressed.

[0163] On the optical axis, the first surface S1 of the first lens 121 can have a convex shape, and the second surface S2 can have a concave shape. The radius of curvature of the second surface S2 on the optical axis can be greater than the radius of curvature of the first surface S1, for example, greater than three or four times or more than the radius of curvature of the first surface S1. Furthermore, the average value of the radii of curvature of the first surface S1 and the second surface S2 of the first lens 121 can be greater than the average value of the absolute values ​​of the radii of curvature of the lens. The first surface S1 and the second surface S2 of the first lens 121 can have a spherical shape. The maximum effective length of the first lens 121 can be the second longest among the lenses. The effective length of the first surface S1 of the first lens 121 can be greater than the average effective length of the object-side surface and the sensor-side surface of the second to sixth lenses 122 to 126. The maximum effective length of the seventh lens 127 can be the longest among the lenses, or it can be the longest among plastic lenses.

[0164] On the optical axis, the third surface S3 of the second lens 122 can be concave, and the fourth surface S4 can be concave. The absolute value of the radius of curvature of the third surface S3 on the optical axis can be smaller than the radius of curvature of the fourth surface S4. The difference (absolute value) between the radii of curvature of the third surface S3 and the fourth surface S4 can be 4 mm or less. The fifth surface S5 of the third lens 124 on the optical axis OA can be convex, and the sixth surface S6 can be convex. The seventh surface S7 of the fourth lens 124 can be concave, and the eighth surface S8 can be concave. The ninth surface S9 of the fifth lens 125 on the optical axis OA can be concave, and the tenth surface S10 can be convex. On the optical axis OA, the eleventh surface S11 of the sixth lens 126 can be concave, and the twelfth surface S12 can be concave. On the optical axis OA, the thirteenth surface S13 of the seventh lens 127 can be convex, and the fourteenth surface S14 can be convex. The seventh lens 127 has a convex shape on both sides and can refract incident light into parallel light directed toward the image sensor 300. The average absolute value of the radii of curvature of the thirteenth and fourteenth surfaces S13 and S14 of the seventh lens 127 can be the second largest among lenses. The third to fourteenth surfaces S3 to S14 are aspherical, and the conic constant K and the fourth to twentieth order aspherical coefficients A to I can be as follows: Figure 23 The representation shown.

[0165] The absolute difference in the radius of curvature between the object-side surface and the sensor-side surface of the third to sixth lenses 123, 124, 125, and 126 can be 10 mm or less. Since the difference in the radius of curvature between the object-side surface and the sensor-side surface of these movable lenses is not set to be large, changes in the optical path can be predicted, and an increase in lens size can be suppressed. Furthermore, since the absolute difference in the radius of curvature between the object-side surface and the sensor-side surface of the first lens 121 is the largest, the amount of incident light can be increased and refracted into the effective area of ​​the second lens 122. At least one or all of the refractive indices of the first lens 121, the fifth lens 125, and the seventh lens 127 can be greater than the refractive indices of the other lenses. Furthermore, the absolute difference in the focal lengths of the first to seventh lenses 121 to 127 can be 23 mm or less.

[0166] The effective length CA1 of the first lens 121 is the second longest among the lenses, and the effective length CA5 of the fifth lens 125 is the shortest. The effective length CA1 of the first lens 121 can be 5 mm or greater. The effective lengths CA5 and CA6 of the fifth lens 125 and the sixth lens 126 can be less than 5 mm. Since the center thickness CT6 of the sixth lens 126 is less than 2 mm and the difference in the absolute value of the radii of curvature on both sides is small, light can be guided to the seventh lens 127 without significantly changing the incident light path.

[0167] Among the absolute values ​​of focal length, the focal length F5 of the fifth lens 125 can be the largest among the lenses. Furthermore, between two adjacent lenses, the absolute difference in focal length between the fifth lens 125 and the sixth lens 126 can be the largest, and the absolute difference in focal length between the second lens 122 and the third lens 123 can be the smallest. The focal lengths of the first to seventh lenses 121 to 127 can satisfy the following conditions.

[0168] Condition 1: |F2| <F1<│F2│ 3

[0169] Condition 2: 0<(│F2│–F3)≤(│F4│-F3)<6 mm

[0170] Condition 3: |F6| <F7<F5

[0171] Condition 4: (│F2│+F3+│F6│) <F5

[0172] At least one of the center thicknesses CT3 and CT5 of the third lens 123 and the fifth lens 125 can be the thickest among the center thicknesses of the lenses, for example, 2 mm or greater. At least one of the center thicknesses CT2 and CT6 of the second lens 122 and the sixth lens 126 can be the thinnest among the center thicknesses of the lenses, thereby allowing adjustment of the optical path according to the positional movement of the second lens group LG2 and the third lens group LG3. The center thicknesses CT3 and CT4 of the third lens 123 and the fourth lens 124 of the second lens group LG2 can both be greater than the sum of the center thicknesses CT1 and CT2 of the first lens 121 and the second lens 122. The sum of the center thicknesses CT3 and CT4 of the third lens 123 and the fourth lens 124 of the second lens group LG2 can be greater than the sum of the center thicknesses CT6 and CT7 of the sixth lens 126 and the seventh lens 127. Therefore, the second lens group LG2 can guide the light incident through the first lens group LG1 to the effective area of the third lens group LG3.

[0173] Depending on the change in magnification according to the operation mode, the optical axis distances DG12 between the first lens group LG1 and the second lens group LG2, DG23 between the second lens group LG2 and the third lens group LG3, and DG34 between the third lens group LG3 and the fourth lens group LG4 can all be at least 0.5 mm and at most 8 mm. Specifically, the optical axis distance DG12 between the first lens group LG1 and the second lens group LG2 can be at least 0.5 mm, for example, within the range of 0.5 mm to 7 mm. The optical axis distance DG23 between the second lens group LG2 and the third lens group LG3 can be at least 1 mm, for example, within the range of 1 mm to 3 mm. The optical axis distance DG34 between the third lens group LG3 and the fourth lens group LG4 can be 0.8 mm or greater, for example, within the range of 0.8 mm to 8 mm. In the first mode, DG12 and DG23, in the second mode, DG12, DG23, and DG34, and in the third mode, DG23 and DG34, can be greater than the BFL. The maximum movement distance Max_mMd13 of the second lens group LG2 and the third lens group LG3 in the first mode, the second mode, and the third mode can satisfy: 4 mm < Max_mMd13 ≤ 5.5 mm. Therefore, the maximum movement distance for the zoom magnification can be reduced, thereby reducing the power consumption of the drive member.

[0174] Depending on the operation mode, the F-number of the optical system 1000 can provide a brightness of 5 or less, and the F-number can be within the range of 2.2 to 5. The aperture stop can be positioned between the first lens group LG1 and the second lens group LG2 and can be arranged, for example, around the fifth surface S5 of the third lens 123.

[0175] Table 5 and Figure 22The items in the above mathematical expression of the optical system 1000 of the third embodiment are shown, including TTL (mm), BFL, effective focal length F (mm), focal length of each lens group, ImgH (mm), effective length (mm), center thickness CT of each lens, center distance CG between two adjacent lenses, TD (mm) (which is the optical axis distance from the first surface S1 to the fourteenth surface S14), focal lengths F1, F2, F3, F4, F5, F6 and F7 (mm) of each of the first to seventh lenses, diagonal FOV (degrees), F number, etc.

[0176] Table 5

[0177] Table 6 can represent the effective focal length F, FOV, F-number, entrance pupil diameter (EPD), SD, and center distances DG12, DG23, and DG34 between adjacent lens groups in the optical system according to the first to third modes of the third embodiment. SD is the distance from the position of the aperture to the optical axis of the image sensor.

[0178] Table 6

[0179] like Figure 24 As shown, the optical system according to the third embodiment can have MTF characteristics according to the first, second, and third modes (wide-angle, intermediate, and telephoto modes). In detail, Figure 24 The graphs show the diffraction MTF characteristics of the optical system 1000 operating in the first to third modes, and it can be seen that the defocus position does not change much depending on the operating mode. Figures 25 to 27 This is a graph showing spherical aberration (longitudinal spherical aberration), astigmatism curvature, and distortion from left to right in the aberration curve diagram of the optical system according to the third embodiment. Figures 25 to 27 In the diagram, the X-axis represents focal length (mm) and distortion (%), while the Y-axis represents the image height. Furthermore, the spherical aberration graphs are plots for light at wavelengths of approximately 435 nm, 486 nm, 546 nm, 587 nm, and 656 nm, while the astigmatism and distortion graphs are plots for light at wavelength 546 nm. In the aberration graphs, the closer each curve is to the Y-axis, the better the aberration correction. It can be seen that the aberration changes little depending on the operating mode (wide-angle, intermediate, telephoto).

[0180] The optical system 1000 according to the first to third embodiments can satisfy at least one or two or more of the mathematical expressions described below. Therefore, the optical system 1000 according to the first to third embodiments can effectively correct the aberration that changes according to the change in the operation mode. The optical system 1000 can adjust the zoom ratio of an object at various magnifications and can have a thin and compact structure.

[0181] Hereinafter, from the distance between the first and second lenses to the distance between the seventh and eighth lenses, the optical axis distance between two adjacent lenses can be defined as CG1 - CG7. The effective lengths of the object-side surface and the sensor-side surface of the first lens 101 to the principal axis effective lengths of the object-side surface and the sensor-side surface of the seventh lens 107 can be defined as CA11, CA12 to CA81, CA82. The units of the thickness, distance, and effective diameter values are mm. In addition, the effective length includes the circular or non-circular shape of the lens surface, and when the lens has a partially circular shape, the effective length can be defined as the principal axis effective length or the maximum effective length.

[0182] [Mathematical Expression 1] nLG2 > 1

[0183] In Mathematical Expression 1, nLG2 represents the number of lenses included in the second lens group LG2. Here, the following relationship can be satisfied: nLG1, nLG2, nLG3 > nLG4. Here, n represents the number of lenses.

[0184] [Mathematical Expression 2] 0.75 < CA1 / CA7 < 0.98

[0185] In Mathematical Expression 2, CA1 is the average value of the maximum effective lengths of the object-side surface and the sensor-side surface of the first lenses 101, 111, and 121, and CA7 is the average value of the maximum effective lengths of the object-side surface and the sensor-side surface of the seventh lenses 107, 117, and 127. If Mathematical Expression 2 is satisfied, the TTL can be reduced. Preferably, 0.8 < CA1 / CA7 < 0.9 can be satisfied.

[0186] [Mathematical Expression 2-1] 0.75 < CA11 / CA72 < 0.98

[0187] In Mathematical Expression 2-1, CA11 is the average value of the maximum effective lengths of the object-side surfaces of the first lenses 101, 111, and 121, and CA72 is the average value of the maximum effective lengths of the sensor-side surfaces of the seventh lenses 107, 117, and 127. Preferably, 0.8 < CA11 / CA72 < 0.9 can be satisfied. When Mathematical Expressions 2 and 2-1 are satisfied, a higher EPD can be provided compared to the optical system.

[0188] [Mathematical Expression 3] 0 < CT1 / CT3 < 1

[0189] In Mathematical Expression 3, the center thickness CT1 of the first lenses 101, 111, and 121 can be less than the center thickness CT3 of the third lenses 103, 113, and 123, and if this is satisfied, the aberration characteristics in the optical system 1000 can be improved. Preferably, 0.2 < CT1 / CT3 < 0.7 can be satisfied. The third lenses 103, 113, and 123 have a center thickness CT3 of 2 mm or more and have a shape that bulges on both sides, so that the third lenses can improve the light incident efficiency of the first lens group LG1 and refract light into the effective area of the fifth lens having the minimum effective length.

[0190] [Mathematical Expression 4] 0 < CT1 / CT4 < 1

[0191] In Mathematical Expression 4, the center thickness of the first lenses 101, 111, and 121 can be less than the center thickness CT4 of the fourth lenses 104, 114, and 124. If this is satisfied, the optical system 1000 can improve the aberration characteristics. Preferably, 0.2 < CT1 / CT4 < 0.8 can be satisfied. Since the center thickness CT4 of the fourth lenses 104, 114, and 124 is thicker than 1.5 mm and has a shape that is recessed on both sides, the center distance between the third and fourth lenses can be further reduced.

[0192] [Mathematical Expression 5] L1R1 L2R1 < 0

[0193] L1R1 is the radius of curvature of the object side surface of the first lenses 101, 111, and 121, and L2R1 is the radius of curvature of the object side surface of the second lens. When the optical system satisfies Mathematical Expression 4, the amount of incident light can be increased, and for example, the incident efficiency of the light reflected over the entire area of the reflection member 400 (see Figure 29 ) can be improved.

[0194] [Mathematical Expression 6] FLG1 < 0

[0195] In Mathematical Expression 6, FLG1 is the effective focal length (EFL) of the first lens group LG1 and can have a value less than 0. FLG1 is the combined focal length of the first and second lenses. When Mathematical Expression 6 is satisfied, the optical aberration of the optical system can be improved, that is, the optical aberration of the first lens group LG1 can be improved.

[0196] [Mathematical Expression 7] 1° < CRA < 20°

[0197] In mathematical expression 7, CRA (Chief Ray Angle) represents the angle of incidence of the chief ray. Depending on the first, second, and third modes in the optical system, the angle of incidence of the chief ray can be at most less than 20 degrees, and can be, for example, 15 degrees or less. The first mode can be a wide-angle mode, the second mode can be a mid-range mode, and the third mode can be a telephoto mode. When mathematical expression 7 is satisfied, the peripheral light ratio is ensured.

[0198] [Mathematical Expression 8] (TTL / DLG1) > 3.5

[0199] In mathematical expression 8, DLG1 represents the optical axis distance of the first lens group LG1. For example, it is the optical axis distance from the center of the object-side surface of the first lenses 101, 111, and 121 to the center of the sensor-side surface of the second lenses 102, 112, and 122. For example, DLG1 refers to the distance (mm) in the optical axis OA from the first surface S1 of the first lenses 101, 111, and 121 to the fourth surface S4 of the second lenses 102, 112, and 122. TTL refers to the distance (mm) in the optical axis OA from the first object-side surface S1 of the first lenses 101, 111, and 121 to the image surface of the image sensor 300. When the optical system 1000 satisfies mathematical expression 8, the optical system 1000 has a relatively small TTL and can ensure peripheral light ratio. Mathematical expression 8 may also include the following mathematical expressions.

[0200] [Mathematical Expression 8-1] (TTL / DLG1) < (TTL / DLG2)

[0201] [Mathematical Expressions 8-2] DLG3 <DLG2

[0202] Here, DLG2 is the optical axis distance of the second lens group LG2, and is the distance from the center of the object-side surface of the third lenses 103, 113, and 123 to the center of the sensor-side surface of the fourth lenses 104, 114, and 124. DLG3 is the optical axis distance of the third lens group LG3, and is the distance from the center of the object-side surface of the fifth lenses 106, 116, and 126 to the center of the sensor-side surface of the sixth lenses 106, 116, and 126.

[0203] [Mathematical Expression 9] 2 <TTL / EPD3<7

[0204] In mathematical expression 9, EPD3 represents the entrance pupil diameter (EPD) of the optical system 1000 when operating in the third mode (i.e., telephoto mode). When the optical system 1000 satisfies mathematical expression 9, the optical system 1000 can ensure a bright image when operating in the third mode, and this can be the minimum condition for ensuring an F-number of 5 or less in telephoto mode. Preferably, 3 can be satisfied. <TTL / EPD3<5。

[0205] [Mathematical Expressions 9-1] 4 <TTL / EPD1<7

[0206] [Mathematical Expression 9-2] 3.5 <TTL / EPD2<6.5

[0207] In mathematical expressions 9-1 and 9-2, EPD1 represents the entrance pupil size of the optical system in the first mode (wide-angle), while EPD2 represents the entrance pupil size of the optical system in the second mode (intermediate). When the optical system meets these conditions, a bright image can be ensured in each mode.

[0208] [Mathematical Expression 10] 2 <CT_Max / CT_Min<6

[0209] In mathematical expression 10, CT_Max represents the thickest center thickness of the lens, and CT_Min represents the thinnest center thickness of the lens. Satisfying mathematical expression 10 can improve the aberration characteristics of the optical system. Preferably, it can satisfy 4. <CT_Max / CT_Min<5.5。

[0210] [Mathematical Expression 11] 1 <CA_Max / CA_Min<3

[0211] In mathematical expression 11, CA_Max represents the effective length or maximum effective length along the principal axis of each lens surface, and CA_Min represents the minimum effective diameter of each lens surface. When mathematical expression 11 is satisfied, a camera module for a thin or compact structure can be provided while maintaining the optical performance of the optical system. Preferably, 1.2 is satisfied. <CA_Max / CA_Min<1.8。

[0212] [Mathematical Expression 12] 0.3 < ΣCG / TTL < 0.8

[0213] In Mathematical Expression 12, ΣCG is the sum of the center distances between adjacent lenses, and the sum of the center distances can be kept constant according to the variations in the first to third modes. When the optical system satisfies Mathematical Expression 12, the moving distances of the second lens group LG2 and the third lens group LG3 and the center distances between adjacent lenses within each lens group can be set according to each mode. Preferably, 0.4 < ΣCG / TTL < 0.7 can be satisfied.

[0214] [Mathematical Expression 13] 0.25 < DLG1 / DLG2 < 0.8

[0215] In Mathematical Expression 13, DLG1 is the optical axis distance of the first lens group LG1, and DLG2 is the optical axis distance of the second lens group LG2. In Mathematical Expression 13, the TTL can be adjusted by setting the optical axis distances of the first lens group LG1 and the second lens group LG2. Preferably, 0.4 < DLG1 / DLG2 < 0.65 can be satisfied.

[0216] [Mathematical Expression 14] 0.5 < DLG2 / DLG3 < 2

[0217] In Mathematical Expression 14, DLG2 is the optical axis distance of the second lens group LG2, and DLG3 is the optical axis distance of the third lens group LG3. Preferably, 1 < DLG2 / DLG3 < 1.5 can be satisfied. When the optical system 1000 according to the embodiment satisfies at least one of Mathematical Expressions 13 and 14, it has a relatively small TTL and can provide various magnifications according to variations in at least three modes.

[0218] [Mathematical Expression 15] 0 < CG1 / TTL < 0.2

[0219] In Mathematical Expression 15, CG2 is the optical axis distance between the first lenses 101, 111, and 121 and the second lenses 102, 112, and 122. When the optical system 1000 satisfies Mathematical Expression 15, the optical system 1000 has a relatively small TTL and can control the stray light incident on the first lens group LG1 to achieve improved optical characteristics. Preferably, 0 < CG2 / TTL < 0.1 can be satisfied.

[0220] [Mathematical Expression 16] 2 < TTL / (DLG2 + DLG3) < 5

[0221] Mathematical expression 16 defines the sum of the TTL and the optical axis distances of the second lens group LG2 and the third lens group LG3. If the optical system 1000 satisfies mathematical expression 16, then the optical system 1000 has a relatively small TTL and can improve chromatic aberration characteristics. Preferably, it can satisfy 2.5. <TTL / (DLG2+DLG3)<3.5。

[0222] [Mathematical Expression 17] 20 < |Vd2–Vd3| < 70

[0223] In mathematical expression 17, Vd2 represents the Abbe number of the second lenses 102, 112, and 122, and Vd3 represents the Abbe number of the third lenses 103, 113, and 123. When the absolute value of the difference between the Abbe numbers of the second and third lenses of the optical system 1000 according to the embodiment satisfies mathematical expression 17, the optical system 1000 can improve chromatic aberration characteristics. Preferably, Vd2 < Vd3, and 45 < Vd3 can be satisfied.

[0224] [Mathematical Expression 18] 15<|Vd6–Vd7|<60

[0225] In mathematical expression 18, Vd7 represents the Abbe number of the seventh lens, and Vd6 represents the Abbe number of the sixth lens. When the absolute value of the difference in Abbe numbers between the sixth and seventh lenses satisfies mathematical expression 18, the optical system 1000 can improve chromatic aberration characteristics. Preferably, Vd7 < Vd6, and 45 < Vd6 can be satisfied.

[0226] [Mathematical Expression 19] 1.6 <Nd1

[0227] In mathematical expression 19, Nd1 represents the refractive index of the first lenses 101, 111, and 121 at the d-line. When the optical system 1000 according to the embodiment satisfies mathematical expression 19, it can disperse the incident light and ensure an effective area of ​​the lens located closer to the sensor than the first lenses 101, 111, and 121. Preferably, 1.65 ≤ Nd1 can be satisfied.

[0228] [Mathematical Expressions 19-1] 1.6 <Nd2

[0229] [Mathematical Expressions 19-2] 1.6 <Nd5

[0230] [Mathematical Expressions 19-3] 1.6 <Nd7

[0231] The refractive indices of the second, fifth, and seventh lenses can exceed 1.6. Within the lens portion, the number of lenses having a refractive index of 1.60 or greater can be three or more, for example, four. Here, the products of the Abbe numbers and refractive indices of the first lenses 101, 111, and 121 and the seventh lenses 107, 117, and 127 are as follows: Condition 1: Nd1 Vd1 < 50 Condition 2: Nd7 Vd7 < 50 [Mathematical expression 20] 0.5 < L1R1 / L2R2 < 1.5 In Mathematical expression 20, L1R1 represents the radius of curvature of the first surface S1 on the object side of the first lenses 101, 111, and 121, and L2R2 represents the radius of curvature of the fourth surface S4 on the sensor side of the second lenses 102, 112, and 122. When the optical system 1000 satisfies Mathematical expression 20, the optical system 1000 can control the stray light incident on the first lens group LG1. Preferably, 1 < L1R1 / L2R2 < 1.3 can be satisfied. Since the second lenses 102, 112, and 122 have concave sensor-side surfaces on the optical axis, an increase in the effective diameter of the third lenses 103, 113, and 123 can be suppressed.

[0232] [Mathematical expression 21] 1 < L1R1 / L3R1 < 3.5

[0233] In Mathematical expression 21, L1R1 represents the radius of curvature of the first surface S1 on the object side of the first lenses 101, 111, and 121, and L3R1 represents the radius of curvature of the fifth surface S5 on the object side of the fourth lenses 103, 113, and 123. When the optical system 1000 according to the embodiment satisfies Mathematical expression 21, the optical system 1000 can have good optical performance at various magnifications. Preferably, 1.5 < L1R1 / L3R1 < 2.5 can be satisfied. <00​​​In mathematical expression 22, L2R2 represents the radius of curvature of the fourth surface S4 on the sensor side of the second lenses 102, 112, and 122. When the optical system 1000 according to an embodiment satisfies mathematical expression 22, the optical system 1000 can have good optical performance at the periphery of the FOV when operating at various magnifications in at least three modes. Preferably, 1.5 < L2R2 / L3R1 < 2.5 can be satisfied. The third lenses 103, 113, and 123 are the lenses closest to the first lens group LG1 within the second lens group LG2, have a biconvex shape on the optical axis, and can have a positive refractive power. Therefore, the distance between the convex sensor-side surface of the third lenses 103, 113, and 123 and the concave object-side surface of the fourth lenses 104, 114, and 124 can be closely closed.

[0236] [Mathematical expression 23] –0.8 < L1R1 / L7R2 < –0.3

[0237] In mathematical expression 23, L7R^2 represents the radius of curvature of the fourteenth surface S14 on the sensor side of the seventh lenses 107, 117, and 127. If the optical system 1000 satisfies mathematical expression 23, the radius of curvature of the sensor-side surface of the last lens can be set.

[0238] [Mathematical expression 23-1] 1 < │L7R1 / L1R1│

[0239] In mathematical expression 23-1, the center thickness of the first lenses 101, 111, and 121 can be reduced by the small radius of curvature of the object-side surface of the first lens. The center thickness of the seventh lenses can be increased by the large radius of curvature of the object-side surface of the seventh lens. This allows light incident on the seventh lens to be refracted toward the image sensor 300 in an almost parallel manner.

[0240] [Mathematical expression 24] 0 < Md12_mLG2 / TTL < 0.5

[0241] In mathematical expression 24, MD12_mLG2 represents the difference in the center distance (unit: mm) after the second lens group LG2 moves when changing from the second mode to the first mode or from the first mode to the second mode. Specifically, MD12_mLG2 represents the moving distance of the second lens group LG2 in the first and second modes, and represents the difference between the optical axis distance between the first lens group LG1 and the second lens group LG2 in the first mode and the optical axis distance between the first lens group LG1 and the second lens group LG2 in the second mode. When the optical system 1000 satisfies mathematical expression 24, the optical system 1000 can minimize the moving distance of the second lens group LG2 when the magnification changes, so that the optical system 1000 can have a thin structure. In addition, since the moving distance can be minimized when controlling the position of the second lens group LG2, it can have improved power consumption characteristics. Preferably, 0 < Md12_mLG2 / TTL < 0.2 can be satisfied.

[0242] [Mathematical expression 25] 0 < Md23_mLG2 / TTL < 0.5

[0243] In mathematical expression 25, MD23_mLG2 refers to the difference in the center distance (unit: mm) after the second lens group LG2 moves when operating from the second mode to the third mode or from the third mode to the second mode. Specifically, MD23_mLG2 refers to the difference between the optical axis distance between the first lens group LG and the second lens group LG2 in the second mode and the optical axis distance between the first lens group LG1 and the second lens group LG2 in the third mode. The maximum moving distance of the second lens group LG2 can be greater than the maximum moving distance of the third lens group LG3. When the optical system 1000 according to the embodiment satisfies mathematical expression 25, the optical system 1000 can minimize the moving distance of the second lens group LG2 when the magnification changes, so that the optical system 1000 can have a thin structure. In addition, when controlling the position of the second lens group LG2, the moving distance can be minimized, so that it can have improved power consumption characteristics. 0.1 < Md23_mLG2 / TTL < 0.2 can be satisfied. In addition, the following condition can be satisfied: Md12_mLG2 < Md23_mLG2.

[0244] [Mathematical expression 26] 0.3 < Md12_mLG2 / DLG2 < 1

[0245] Mathematical expression 26 can set the moving distance of the second lens group LG2 and the optical axis distance of the second lens group LG2. When the optical system 1000 satisfies mathematical expression 26, the optical system 1000 can minimize the moving distance of the second lens group LG2 when the magnification changes, thus allowing the optical system 1000 to have a slim structure. Furthermore, by controlling the position of the second lens group LG2, the moving distance can be minimized, thereby improving power consumption characteristics. Preferably, 0.4 can be satisfied. <Md12_mLG2 / DLG2<0.75。

[0246] [Mathematical Expression 27] 0.3 <Md23_mLG3 / DLG3<0.9

[0247] In mathematical expression 27, Md23_mLG3 represents the difference in center distance after the movement of the third lens group LG3 when changing from the second mode to the third mode or from the third mode to the second mode. When the optical system 1000 satisfies mathematical expression 27, the optical system 1000 can minimize the movement distance of the third lens group LG3 when the magnification changes, thus the optical system 1000 can have a slim structure. Furthermore, by controlling the position of the third lens group LG3, the movement distance can be minimized, thus the optical system 1000 can have improved power consumption characteristics. Preferably, 0.4 can be satisfied. <Md23_mLG3 / DLG3<0.8。

[0248] [Mathematical Expression 28] 0 <Md23_mLG3 / TTL<0.5

[0249] In mathematical expression 25, Md23_mLG3 refers to the difference (in mm) in the center distance (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 is the difference between the optical axis distance between the second lens group LG2 and the third lens group LG3 in the second mode and in the third mode. When the optical system 1000 satisfies mathematical expression 25, the optical system 1000 can minimize the movement distance of the third lens group LG3 when the magnification changes, thus allowing the optical system 1000 to have a slim structure. Furthermore, by controlling the position of the third lens group LG3, the movement distance can be minimized, thereby achieving improved power consumption characteristics. (The last sentence appears to be incomplete and possibly refers to a different expression.) <Md23_mLG3 / TTL<0.2。

[0250] [Mathematical Expression 29] 1 <Md12_mLG3 / DLG3<3

[0251] Mathematical expression 26 can set the moving distance and optical axis distance of the third lens group LG3. When the optical system 1000 satisfies mathematical expression 26, the optical system 1000 can minimize the moving distance of the third lens group LG3 when the magnification changes, thereby achieving a slim structure. Furthermore, by controlling the position of the third lens group LG3, the moving distance can be minimized, thereby achieving improved power consumption characteristics. Preferably, 1.2 can be satisfied. <Md12_mLG3 / DLG3<2。

[0252] [Mathematical Expression 30] 1 <Md1(DG12 / DG23)<5

[0253] In mathematical expression 30, Md1(DG12 / DG23) represents the ratio between the center distance DG12 between the first and second lens groups and the center distance DG23 between the second and third lens groups in the first mode. When the optical system 1000 according to the embodiment satisfies mathematical expression 30, the optical system 1000 can have improved optical characteristics at the first magnification. Specifically, the optical system 1000 can have improved aberration characteristics at the first magnification and can improve the optical performance at the center and periphery of the FOV. Preferably, 2 can be satisfied. <Md1(DG12 / DG23)<3.3。

[0254] [Mathematical Expression 31] 0.2 <Md3(DG12 / DG23)<0.9

[0255] In mathematical expression 31, Md3(DG12 / DG23) represents the ratio between the center distance DG12 between the first and second lens groups and the center distance DG23 between the second and third lens groups in the third mode. When the optical system 1000 according to the embodiment satisfies mathematical expression 31, the optical system 1000 can have improved optical characteristics at the second magnification. Specifically, the optical system 1000 can have improved aberration characteristics at the second magnification and can improve the optical performance at the periphery of the FOV. Preferably, 0.3 can be satisfied. <Md3(DG12 / DG23)<0.7。

[0256] [Mathematical Expression 32] 2 <Md_CG_Max / Md_CG_Min<8

[0257] Md_CG_Max represents the maximum center distance between adjacent lenses when the second lens group LG2 and the third lens group LG3 move according to the first to third modes, and Md_CG_Min represents the minimum center distance between adjacent lenses. When mathematical expression 32 is satisfied, the center distance between lenses in an optical system with variable lens groups can be set, and the movement distance can be adjusted.

[0258] [Mathematical Expression 33] 1 mm <Max_mMd13<7 mm

[0259] Max_mMd13 represents the maximum distance that the second and third lens groups can move from the first mode to the third mode or from the third mode to the first mode. When the optical system satisfies mathematical expression 33, the power consumption of the driving components can be reduced.

[0260] [Mathematical Expression 34] 5 <TTL / Max_mLG2<5.6

[0261] Max_mLG2 is the maximum travel distance of the second lens group LG2. If the optical system satisfies mathematical expression 34, the power consumption of the second lens group LG2 can be reduced based on the travel distance compared to TTL.

[0262] [Mathematical Expressions 35] 5.2 <TTL / Max_mLG3<5.8

[0263] Max_mLG3 is the maximum movement distance of the third lens group LG3. If the optical system satisfies the mathematical expression 35, the power consumption of the third lens group LG3 can be reduced based on the movement distance compared to TTL.

[0264] [Mathematical Expression 36] 0.5 mm ≤ Md3_DG12 < 1.5 mm

[0265] MD3_DG12 is the center distance between the first and second lens groups in the third mode. When the optical system satisfies mathematical expression 36, and when the first lens group LG1 and the second lens group LG2 are in a telephoto mode with the closest center distance, the center distance between the first lens group LG1 and the second lens group LG2 is set to 0.5 mm or greater, thereby reducing the power consumption of the driving components and suppressing optical losses. Preferably, 0.5 mm ≤ Md3_DG12 < 1 mm can be satisfied.

[0266] [Mathematical Expression 37] LG1_Vd2<35

[0267] LG1_Vd2 is the Abbe number of the second lens in the first lens group, for example, the Abbe number of the second lens. When the optical system satisfies mathematical expression 37, aberration characteristics can be corrected, or aberration characteristics that have changed due to the movement of another lens group can be corrected.

[0268] [Mathematical Expression 38] LG3_Vd1<35

[0269] LG3_Vd1 is the Abbe number of the first lens in the third lens group, for example, the Abbe number of the fifth lens. If the optical system satisfies mathematical expression 38, then aberration characteristics caused by the fifth and sixth lenses can be corrected.

[0270] [Mathematical Expression 39] LG4_Nd>1.6

[0271] LG4_Nd1 is the refractive index of the lens in the fourth lens group, for example, the refractive index of the seventh lens. If the optical system satisfies mathematical expression 39, the dispersion can be adjusted to cover a BFL of less than 3 mm, thereby illuminating the entire area of ​​the image sensor 300.

[0272] [Mathematical Expressions 40] 20 <Aver_Vd<50

[0273] In mathematical expression 40, Aver_Vd is the average Abbe number of the first to seventh lenses. When the optical system satisfies mathematical expression 40, the optical system 1000 can have improved aberration characteristics and resolution. Preferably, it can satisfy 25. <Aver_Vd<35。

[0274] [Mathematical Expression 41] 1.5 <Aver_Nd<1.8

[0275] In mathematical expression 40, Aver_Nd is the average refractive index of the first to seventh lenses. When the optical system satisfies mathematical expression 41, the optical system 1000 can have improved aberration characteristics and resolution. Preferably, it can satisfy 1.6. <Aver_Nd<1.67。

[0276] [Mathematical Expression 41-1] 10 < ∑Vd / ∑Nd < 30

[0277] In mathematical expression 41-1, ∑Vd represents the sum of the Abbe numbers of each of the multiple lenses. ∑Nd represents the sum of the refractive indices of each of the multiple lenses. When the optical system 1000 according to the embodiment satisfies mathematical expression 41-1, the optical system 1000 can have improved aberration characteristics and resolution. Preferably, mathematical expression 41-1 can satisfy: 17 < ∑Vd / ∑Nd < 25.

[0278] [Mathematical Expression 42] 2<│FLG1 / FLG2│<4

[0279] In mathematical expression 42, FLG1 represents the effective focal length (EFL) of the first lens group LG1, and FLG2 represents the effective focal length of the second lens group LG2. FLG2 is the composite focal length of the fourth and fifth lenses. If mathematical expression 42 is satisfied, the size of the optical system can be reduced, for example, to TTL. Preferably, FLG2 > 0. FLG3 is the composite focal length of the sixth and seventh lenses, and FLG3 < 0, and can satisfy the following condition: |FLG1| > |FLG4| > FLG2. FLG4 is the focal length of either the fourth or seventh lens group.

[0280] [Mathematical Expression 43] 1 < FMd3 / FMd1 < 3

[0281] In Mathematical Expression 43, FMd1 represents the effective focal length of the optical system in the first mode, and FMd3 represents the effective focal length of the optical system in the third mode. Preferably, 1.5 < FMd3 / FMd1 < 2.5 can be satisfied. When the optical system satisfies Mathematical Expression 43, the effective focal length can be adjusted according to the first and third modes.

[0282] [Mathematical Expression 44] 2 < FMd2 / EPD2 < 6

[0283] In Mathematical Expression 44, FMd2 represents the effective focal length of the optical system in the second (intermediate) mode, and EPD2 represents the EPD of the optical system 1000 in the second mode. When the optical system 1000 according to the embodiment satisfies Mathematical Expression 44, the optical system 1000 can ensure a bright image when operating in the second mode. Preferably, 3 < FMd2 / EPD2 < 5 can be satisfied.

[0284] [Mathematical Expression 45] 1 < FMd1 / EPD1 < 4

[0285] In Mathematical Expression 34, FMd1 represents the effective focal length of the optical system in the first (wide-angle) mode, and EPD1 represents the EPD of the optical system 1000 when operating in the first mode. When the optical system 1000 according to the embodiment satisfies Mathematical Expression 45, the optical system 1000 can ensure a bright image when operating in the first mode. Preferably, 2 < FMd1 / EPD1 < 3.5 can be satisfied.

[0286] [Mathematical Expression 46] FMd < FMd2 < FMd3

[0287] In Mathematical Expression 46, FMd1, FMd2, and FMd3 represent the effective focal lengths of the optical system in the first, second, and third modes. The effective focal length in the third mode can be the largest, and the effective focal length in the first mode can be the smallest.

[0288] [Mathematical Expression 47] 0.8 < TTL / FMd2 < 2

[0289] Mathematical Expression 47 compares TTL and the effective focal length in the second mode to adjust TTL. Preferably, 1 ≤ TTL / FMd2 < 1.5 can be satisfied.

[0290] [Mathematical Expression 48] 1 < TTL / FMd1 < 3

[0291] Mathematical expression 47 compares the effective focal length in TTL and the first mode to adjust the TTL. Preferably, it can satisfy 1.5. <TTL / FMd1<2。

[0292] [Mathematical Expression 49] 1 <CA_Max / ImgH<3

[0293] In mathematical expression 49, CA_Max refers to the maximum effective length (CA) among the lens surfaces of the plurality of lenses included in the optical system 1000. ImgH is the distance from the 0-field region of the image sensor 300 at the center of the image surface overlapping the optical axis OA to the 1.0-field region of the image sensor 300. ImgH represents half the maximum diagonal length of the effective area of ​​the image sensor 300. When the optical system 1000 according to the embodiment satisfies mathematical expression 49, the optical system 1000 can be provided in a thin and compact manner. Furthermore, the optical system 1000 can achieve high resolution and high image quality. ImgH ranges from 2 mm or more, for example, from 2 mm to 4 mm. Here, the effective lengths CA1 to CA7 of the first to seventh lenses 101 to 107 can satisfy the following conditions.

[0294] Condition 1: CA6 < (ImgH) 2) <CA7

[0295] Condition 2: CA2 < (ImgH) 2)

[0296] Condition 3: CA2 <CA1

[0297] Condition 4: CA5 <CA4

[0298] CA1-CA7 are the average values ​​of the maximum effective lengths of the object-side surface and sensor-side surface of the first to seventh lenses, respectively.

[0299] [Mathematical Expressions 50] 5 <TTL / ImgH<12

[0300] If the optical system 1000 satisfies mathematical expression 39, then the optical system 1000 can have a smaller TTL, thereby allowing the optical system 1000 to be thin and compact. Preferably, the TTL range is 6 < TTL / ImgH < 10.

[0301] [Mathematical Expression 51] 0 <BFL / ImgH<1

[0302] If the optical system 1000 according to the embodiment satisfies mathematical expression 51, it can ensure the BFL required for high-pixel (e.g., 48 megapixels or greater) or 2-inch or larger image sensors. Furthermore, if the optical system 1000 satisfies mathematical expression 51, it can operate at various magnifications while maintaining TTL, and can exhibit excellent optical characteristics at the center and periphery of the FOV.

[0303] [Mathematical Expression 52] 2 <FMd1 / ImgH<6

[0304] If the optical system 1000 according to the embodiment satisfies mathematical expression 52, the effective focal length of the first mode can be set according to the effective length of the image sensor. Preferably, it can satisfy 4 <FMd1 / ImgH<5。

[0305] [Mathematical Expression 53] 6 <FMd3 / ImgH<12

[0306] If the optical system 1000 according to the embodiment satisfies mathematical expression 53, the effective focal length of the third mode can be set according to the effective length of the image sensor. Preferably, it can satisfy 7. <FMd3 / ImgH<11。

[0307] [Mathematical Expression 54] 2 mm <ImgH

[0308] Mathematical expression 56 can set half the diagonal length of image sensor 300 and provide the size of the image sensor for the zoom magnification optical system. Mathematical expression 54 preferably satisfies: 2.40 mm. <ImgH<4 mm。

[0309] [Mathematical Expression 55] 10 mm <F<40 mm

[0310] F represents the range of minimum and maximum effective focal lengths according to the first to third modes, and preferably, it can satisfy 10 mm. <F<32 mm。

[0311] [Mathematical Expression 56] TTL < 30 mm

[0312] TTL refers to the distance along the optical axis OA from the center of the first surface S1 of the first lenses 101, 111, 121 to the surface of the image sensor 300. In mathematical expression 55, a zoom magnification optical system can be provided by setting the TTL to more than 15 mm. Preferably, 15 mm can be satisfied. <TTL<28 mm。

[0313] [Mathematical Expression 57] 3 mm <EPD1<EPD2<EPD3<9 mm

[0314] EPD1, EPD2, and EPD3 represent the range of EPDs of the optical system 1000 according to the first to third modes.

[0315] [Mathematical Expression 58] 8° <FOV3<FOV2<FOV1<45°

[0316] In mathematical expression 58, FOV refers to the diagonal field of view (in degrees) of optical system 1000. FOV1 represents the FOV in the first mode, FOV2 represents the FOV in the second mode, and FOV3 represents the FOV in the third mode. Depending on the operating mode, the angle can be set in the order of wide-angle, intermediate, and telephoto modes. Preferably, 10° can be satisfied. <FOV<30°。

[0317] [Mathematical Expression 59] 0.5 <TD / TTL<1

[0318] TD is the optical axis distance from the center of the object-side surface of the first lens to the center of the sensor-side surface of the seventh lens. The size of TD relative to TTL can be set if the optical system satisfies mathematical expression 59.

[0319] [Mathematical Expression 60] 0.5 <SD1 / TTL<1

[0320] SD1 is the optical axis distance from the aperture position to the surface of the image sensor in the first mode (wide-angle mode). If the optical system satisfies the mathematical expression 60, the amount of light passing between the lenses can be controlled by setting the position of the aperture stop.

[0321] [Mathematical Expression 61] 10mm <SD1<SD2<SD3<25mm

[0322] SD2 is the optical axis distance from the aperture stop position to the image sensor surface in the second mode (intermediate mode). SD3 is the optical axis distance from the aperture stop position to the image sensor surface in the third mode (telephoto mode). If the optical system satisfies mathematical expression 61, the amount of light passing between the lenses can be controlled by adjusting the position of the aperture stop according to each mode.

[0323] [Mathematical Expression 62] 1 <SD3 / SD1<2

[0324] If the optical system satisfies mathematical expression 62, the maximum range of aperture stop variation can be set, thereby allowing light output control from wide-angle mode to telephoto mode.

[0325] [Mathematical Expression 64] 10 <TD / BFL

[0326] If the optical system satisfies mathematical expression 64, the optical axis distance (BFL) between the last lens and the image sensor can be set, thereby allowing for a reduced TTL. Preferably, it can satisfy 10. <TD / BFL<20。

[0327] [Mathematical Expression 65] 0.8 mm <BFL<3 mm

[0328] If the optical system satisfies mathematical expression 65, the optical axis distance (BFL) between the last lens and the image sensor can be set narrower, thereby reducing the TTL. Furthermore, the distance between the filter 500 and the image sensor 300 can be reduced. Preferably, the following condition can be satisfied: 1 m <BFL<3 mm。

[0329] [Mathematical Expression 66] Md3_Fno≤5

[0330] MD3_Fno is the F-number of the optical system in third mode. A bright optical system can be provided if the optical system satisfies the mathematical expression 66.

[0331] [Mathematical Expression 67] 0.55 <CA7x / CA7y<0.9

[0332] CA7y is the average of the effective lengths of the object-side and sensor-side surfaces of the seventh lenses 107, 117, and 127 along the second direction Y, and CA7x is the average of the effective lengths of the object-side and sensor-side surfaces of the first lenses 107, 117, and 127 along the first direction X. When this mathematical expression 67 is satisfied, the length of the seventh lens with the maximum effective length along the first direction in lens portions 100, 100A, and 100B can be reduced, thereby providing a thinner optical system and camera module along the first direction.

[0333] [Mathematical Expression 67-1] 0.55 <CA1x / CA1y<0.9

[0334] CA1y is the average of the effective lengths of the object-side and sensor-side surfaces of the first lenses 101, 111, and 121 along the second direction Y, and CA1x is the average of the effective lengths of the object-side and sensor-side surfaces of the first lenses 101, 111, and 121 along the first direction X. When mathematical expression 67 is satisfied, the length of the first lens along the first direction can be reduced, thereby providing a thin optical system and camera module along the first direction.

[0335] [Mathematical Expression 68] (CA72x / CA72y) ≤ CA71x / CA71y)

[0336] CA71x and CA71y are the effective lengths of the object-side surfaces of the seventh lenses 107, 117, and 127 along the first direction X and the second direction Y, and CA72x and CA72y are the effective lengths of the sensor-side surfaces of the seventh lenses 107, 117, and 127 along the first direction X and the second direction Y. If this mathematical expression 70 is satisfied, the length and area of ​​the object-side surfaces of the seventh lenses can be set to be equal to or greater than the length and area of ​​the sensor-side surfaces.

[0337] [Mathematical Expression 69]

[0338] In mathematical expression 69, Z represents the sag, which can refer to the distance along the optical axis from any position on the aspherical surface to the vertex of the aspherical surface. Furthermore, Y can refer to the distance along a direction perpendicular to the optical axis from any position on the aspherical surface to the optical axis. Additionally, "c" can represent the curvature of the lens, and "K" can represent the conic constant. Furthermore, "A", "B", "C", "D", "E", and "F" can represent aspherical coefficients ranging from the 4th to the 14th order.

[0339] The optical system 1000 according to the embodiment can satisfy at least one of the above mathematical expressions 1 to 68. Therefore, the optical system 1000 and the camera module can have improved optical characteristics. Specifically, since the optical system 1000 satisfies at least one or more of the mathematical expressions 1 to 68, it can effectively compensate for the degradation of optical characteristics and peripheral image quality caused by the movement of the lens group, such as chromatic aberration, vignetting, and diffraction effects. Furthermore, the optical system 1000 according to the embodiment can significantly reduce the movement distance of the lens group and provide autofocus (AF) functionality for various magnifications with excellent power consumption characteristics.

[0340] The optical system 1000 according to the embodiment satisfies at least one or more of mathematical expressions 1 to 68, thereby providing improved assembly and mechanical stability. Furthermore, the optical system 1000 and the camera module including the optical system can have a compact structure due to their slim profile.

[0341] Tables 7 and 8 show the results of the aforementioned mathematical expressions 1 to 68 for the optical system 1000 according to the embodiment. Referring to Table 7, the optical system 1000 satisfies at least one, two, or three of mathematical expressions 1 to 34. Specifically, the optical system 1000 according to the embodiment satisfies all of mathematical expressions 1 to 34. Therefore, the optical system 1000 can exhibit excellent optical performance and superior optical characteristics at both the center and periphery of the field of view (FOV).

[0342] Table 7

[0343] Referring to Table 8, it can be seen that the optical system 1000 satisfies at least one, two, three, or more of mathematical expressions 35 to 68. Specifically, it can be seen that the optical system 1000 according to the embodiment satisfies all of mathematical expressions 35 to 68. Therefore, the optical system 1000 can have good optical performance and excellent optical characteristics at the center and periphery of the FOV.

[0344] Table 8

[0345] Reference Figure 29 The camera module includes the optical system 1000 disclosed above, and the optical system 1000 may include a reflective member 400 facing an object, lens portions 100, 100A, and 100B having multiple lens groups LG1-LG4, and an image sensor 300. The camera module may include a first driving member DM1 driving a second lens group LG2, and a second driving member DM2 driving a third lens group LG3. The reflective member 400 may be positioned in the path of light reflected onto the object. The reflective member 400 may be positioned closer to the object than the lens portions 100, 100A, and 100B. That is, the reflective member 400, lens portions 100, 100A, and 100B, and image sensor 300 may be arranged in an order from the object side toward the top.

[0346] The reflecting member 400 can alter the path of externally incident light. The reflecting member 400 may include a right-angle prism. When the reflecting member 400 includes a right-angle prism, it can reflect the path of light incident at a 90-degree angle onto the camera module 1000 along a second optical axis direction OA2 and redirect it to the first optical axis direction OA2. The reflecting member 400 can be rotated or tilted to adjust the path of light reflected onto the object. For example, the reflecting member 400 can reflect light incident along the second direction OA2 onto itself and redirect the light path to the optical axis direction OA1, which is the orientation of the plurality of lenses in the lens portions 100, 100A, and 100B.

[0347] If the camera module includes a reflective member 400, it can be applied to a foldable camera that reduces the thickness of the camera module. The camera module is arranged parallel to the surface of the mobile terminal and can redirect light incident along a second optical axis direction OA2 perpendicular to the surface of the mobile terminal to a first optical axis direction OA1 parallel to the surface of the mobile terminal. Therefore, the camera module 1000, including lens portions 100, 100A, and 100B, can have a low height in the direction perpendicular to the surface of the mobile terminal, thereby having a thinner thickness within the mobile terminal, and thus also reducing the thickness of the device.

[0348] The third driving member 410 can be connected to the reflector 400. The third driving member 410 may include at least one actuator. For example, the third driving member 410 may include at least one of a voice coil motor (VCM), a piezoelectric device, a shape memory alloy, and a MEMS device. The third driving member 410 can use the driving force of the actuator to move the reflector 400. For example, the third driving member 410 can tilt the reflector 400 along a first axis or a second axis. Specifically, the third driving member 410 can tilt the reflector 400 along a second direction (Y-axis) that serves as the axis of rotation. Furthermore, the third driving member 410 can tilt the reflector 400 about a third third direction OA1 (Z-axis direction) that serves as the axis of rotation. Therefore, the camera module can compensate for camera shake.

[0349] The camera module includes a sensing unit (not shown) for detecting camera module jitter, and the sensing unit can detect rotational and positional changes applied to the camera module. The sensing unit may include at least one of a sensor (such as a gyroscope sensor) for detecting changes in angular velocity and an accelerometer sensor for detecting changes in acceleration.

[0350] The camera module can control the movement of the reflective member 400 via control signals. Specifically, when shake occurs in the camera module, information about the shake, such as the rotation and positional changes of the sensor, can be detected, and shake compensation can be performed. Therefore, the camera module according to the embodiment can operate in wide-angle, intermediate, and telephoto modes via the first drive member DM1 and the second drive member DM2, and can effectively compensate for rotational and positional shake when shooting a subject. Thus, the camera module can have improved optical characteristics.

[0351] Figure 30 This is a diagram illustrating a camera module disclosed in an embodiment applied to a mobile terminal. (Refer to...) Figure 30The mobile terminal 1 may include the camera module 10 disclosed in the embodiments on its rear surface. As another example, the mobile terminal 1 may include the camera module disclosed in the embodiments on its front surface. The camera module 10 may include image capture functionality. Furthermore, the camera module 10 may include at least one of autofocus functionality, zoom functionality, and optical image stabilization (OIS) functionality. The camera module 10 can process still images or video frames acquired by the image sensor 300 in shooting mode or video call mode. The processed image frames may be displayed on a display unit (not shown) of the mobile terminal 1 and stored in a memory (not shown). Furthermore, although not shown in the figures, the camera module may be further arranged on the front of the mobile terminal 1. For example, the camera module 10 may include a first camera module 10A and a second camera module 10B. In this case, at least one of the first camera module 10A and the second camera module 10B may include the aforementioned optical system 1000. Therefore, the camera module 10 can have a slim structure and can capture objects at various magnifications. The mobile terminal 1 may also include an autofocus device 31. The autofocus device 31 may include an autofocus function using a laser. The autofocus device 31 can be primarily used in situations where the autofocus function of the image from the camera module 10 is degraded, such as at close range of 10 m or less or in dark environments. The autofocus device 31 may include a light-emitting unit comprising a vertical-cavity surface-emitting laser (VCSEL) semiconductor element, and a light-receiving unit such as a photodiode that converts light energy into electrical energy.

[0352] The mobile terminal 1 may also include a flash module 33. The flash module 33 may include a light-emitting element therein. The flash module 33 may emit light within the visible light wavelength range. For example, the flash module 33 may emit white light or light of a similar color. However, the embodiments are not limited to this, and the flash module 33 may emit light of various colors. The flash module 33 may be operated via the mobile terminal's camera or through user control.

[0353] The features, structures, and effects described in the above embodiments are included in at least one embodiment of the invention and are not necessarily limited to a single embodiment. Furthermore, the features, structures, and effects shown in each embodiment can be combined or modified by those skilled in the art in other embodiments. Therefore, such combinations and modifications should be interpreted as falling within the scope of the invention. Moreover, although embodiments have been described above, they are merely examples and not limitations on the invention. Those skilled in the art will understand that various modifications and applications not shown above are possible without departing from the essential characteristics of the embodiments. For example, each component specifically shown in the embodiments can be modified and implemented. Furthermore, differences associated with such modifications and applications should be interpreted as falling within the scope of the invention as defined in the appended claims.

Claims

1. A camera module, comprising: The first lens group is positioned adjacent to the object and has negative (-) refractive power; The second lens group is disposed on the sensor side of the first lens group; The third lens group is disposed on the sensor side of the second lens group; as well as The fourth lens group is disposed on the sensor side of the third lens group and has negative (-) refractive power. The second and third lens groups move along the optical axis of the lenses in the first to fourth lens groups to perform zoom from wide-angle mode to telephoto mode. In this embodiment, at least one of the second and third lens groups has a greater number of lenses than the fourth lens group. Wherein, the optical axis distance of the second lens group is greater than the optical axis distance of the first lens group, and The fourth lens group includes a lens having the largest effective length among the effective lengths of the lenses in the first to fourth lens groups.

2. The camera module according to claim 1, in, Based on the zoom ratio, the maximum movement distance of the second or third lens group is defined as Max_mMd13, and Wherein, the following mathematical expression is satisfied: 1 mm <Max_mMd13<7 mm。 3. The camera module according to claim 1, in, In the telephoto mode, the minimum optical axis distance between the first lens group and the second lens group is Md3_DG12, and Among them, the following mathematical expression is satisfied: 0.5 mm ≤ Md3_DG12 < 1.5 mm.

4. The camera module according to any one of claims 1 to 3, wherein, The lens closest to the object in the first lens group has positive refractive power and a meniscus shape that bulges toward the object.

5. The camera module according to claim 4, wherein, The lens closest to the image sensor in the seventh lens group has positive refractive power and a biconvex shape.

6. The camera module according to claim 5, wherein, The lens closest to the image sensor among the lenses included in the first to fourth lens groups has the largest effective length.

7. The camera module according to any one of claims 1 to 4, in, The seventh lens is made of glass.

8. The camera module according to any one of claims 1 to 4, wherein, The first lens has a spherical shape and is made of glass.

9. The camera module according to any one of claims 1 to 4, in, The number of lenses in the first lens group is equal to the number of lenses in the second and third lens groups, and Each of the first to third lens groups includes a lens with refractive power having opposite signs.

10. The camera module according to claim 5, further comprising: A reflective element is disposed on the object side of the first lens group. The lens closest to the image sensor has a shape in which the effective lengths along a first direction and a second direction perpendicular to the optical axis are different.

11. A camera module, comprising: The first lens group includes a first lens and a second lens arranged sequentially from the object side toward the image sensor, and the first lens group has negative refractive power. The second lens group is disposed on the sensor side of the first lens group; The third lens group is disposed on the sensor side of the second lens group; as well as The fourth lens group has a last lens disposed between the third lens group and the image sensor, and has positive refractive power. The second and third lens groups move along the optical axis of the lenses in the first to fourth lens groups to perform zoom from wide-angle mode to telephoto mode. The object-side surface of the first lens has a convex shape along the optical axis. Wherein, the absolute value of the radius of curvature of the sensor-side surface of the first lens is greater than the radius of curvature of the object-side surface of the first lens. The positions of the first lens group and the fourth lens group are fixed on the optical axis. The number of lenses in the second and third lens groups is less than the number of lenses in the fourth lens group. Among the optical axis distances of the first to fourth lens groups, the second lens group has the largest optical axis distance. Wherein, the optical axis distance from the first lens group to the fourth lens group is the distance along the optical axis from the object-side lens to the sensor-side lens disposed in each lens group, and The effective length of the first lens is less than the effective length of the last lens, but greater than the effective lengths of the lenses in the second and third lens groups.

12. The camera module according to claim 11, in, The first lens has a refractive index Nd1 and an Abbe number Vd1. The last lens has a refractive index Ndn and an Abbe number Vdn, and Wherein, the following mathematical expression is satisfied: Nd1 × Vd1<50, and Ndn × Vdn<50.

13. The camera module according to claim 11, comprising: A reflective component is disposed on the object side of the first lens. Wherein, at least one of the first lens and the last lens has a shape in which the effective lengths along a first direction and a second direction perpendicular to the optical axis are different.

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