Optical system and camera module

Abstract

An optical system according to an embodiment of the present invention comprises first to third lens groups disposed along an optical axis, wherein the first lens group has a positive (+) refractive power, the second lens group has a positive (+) refractive power, the third lens group has a negative (-) refractive power, the first lens group includes a first lens and a second lens, which is a prism lens, the second lens group includes a third lens, a fourth lens and a fifth lens, the third lens group includes a sixth lens and a seventh lens, the first lens group and the second lens group are fixed groups, and the third lens group is a moving group.

Description

Optical system and camera module

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

[0002] Camera modules capture objects and store them as images or videos, and are used in a variety of applications. In particular, camera modules are manufactured in ultra-small sizes and are used in portable devices such as smartphones, tablet PCs, and laptops, as well as drones and vehicles, providing a variety of functions.

[0003] For example, the optical system of a camera module may include an imaging lens that forms an image, and an image sensor that converts the formed image into an electrical signal. At this time, the camera module may perform an autofocus (AF) function that automatically adjusts the distance between the image sensor and the imaging lens to align the focal length of the lens, and may perform a zooming function of zooming up or zooming out to increase or decrease the magnification of a distant object to take a picture through a zoom lens. In addition, the camera module adopts an image stabilization (IS) technology to correct or prevent shaking of the image caused by movement of the camera due to an unstable fixing device or movement of the user.

[0004] The most crucial element for these camera modules to capture images is the imaging lens that forms the image. Recently, interest in high-performance features, such as high definition and resolution, has been increasing, and research is underway on optical systems that incorporate multiple lenses to achieve these goals.

[0005] For example, research is being conducted using multiple imaging lenses with positive (+) or negative (-) refractive power to implement a high-performance optical system. An optical system including multiple lenses may have a set effective focal length (EFL). In this case, if the effective focal length (EFL) value is relatively large, the lens adjacent to the object side has a large aperture or has the largest aperture among the multiple lenses. Accordingly, since the lens closest to the object side has a relatively large size, there is a problem that it is difficult to miniaturize the optical system.

[0006] An optical system comprising multiple lenses can be relatively tall. For example, as the number of lenses increases, the distance between the image sensor and the object plane of the adjacent lens may increase. Consequently, the overall thickness of a mobile device, such as a smartphone, in which the optical system is positioned may increase, making miniaturization difficult.

[0007] Camera modules for close-range photography have shorter TTLs than conventional camera modules. Alternatively, camera modules for long-range photography have longer TTLs than conventional camera modules. However, portable terminals have limited installation space for camera modules, making it difficult to mount long-range camera modules or camera modules capable of adjusting the image magnification (zoom camera modules). Therefore, a new optical system capable of solving the aforementioned problems is required.

[0008] The present embodiment seeks to provide an optical system and camera module with improved optical characteristics.

[0009] In addition, it is possible to provide an optical system that can be implemented in a small and compact manner.

[0010] In addition, an optical system may be provided in which the lengths of at least one lens adjacent to the object side or adjacent to the outside of the terminal among a plurality of lenses are different in the first direction and the second direction. In other words, an optical system may be provided in which the lengths of at least one or more of the lenses are different in the directions of two axes that are orthogonal to each other.

[0011] Additionally, we aim to provide an optical system applicable to a folded camera or macro mode having a thin thickness or height.

[0012] In order to solve the above technical problem, an optical system according to an embodiment of the present invention includes first to third lens groups arranged along an optical axis, wherein the first lens group has positive (+) refractive power, the second lens group has positive (+) refractive power, the third lens group has negative (-) refractive power, the first lens group includes a first lens and a second lens which is a prism lens, the second lens group includes a third lens, a fourth lens and a fifth lens, the third lens group includes a sixth lens and a seventh lens, the first lens group and the second lens group are fixed groups, and the third lens group is a moving group.

[0013] In the above optical axis, the first lens may have a meniscus shape convex toward the object side.

[0014] The object-side surface of the first lens on the optical axis may have a convex shape, and the object-side surface of the fourth lens on the optical axis may have a convex shape.

[0015] The object-side surface of the third lens on the optical axis may have a convex shape, and the fourth lens on the optical axis may have a meniscus shape convex toward the object side.

[0016] The above first lens may have positive (+) refractive power.

[0017] The third lens may have positive (+) refractive power, the fourth lens may have negative (-) refractive power, and the fifth lens may have positive (+) refractive power.

[0018] The sixth lens may have positive (+) refractive power, and the seventh lens may have negative (-) refractive power.

[0019] The following condition can be satisfied. <Condition> 0.1 < LG3_stroke < 1 (In the above condition, LG3 is the stroke length of the third lens group.)

[0020] The following condition can be satisfied. <Condition> 2 < TTL / ImgH < 5 (In the above condition, TTL is the optical axis distance from the vertex of the object-side surface of the lens placed closest to the object-side of the optical system to the upper surface of the image sensor, and ImgH is the maximum diagonal length of the image sensor.)

[0021] In order to solve the above technical problem, an optical system according to an embodiment of the present invention includes first to seventh lenses arranged along an optical axis, wherein the first lens has positive refractive power, the second lens is a prism lens, the third lens has positive refractive power, the fourth lens has negative refractive power, the fifth lens has positive refractive power, the sixth lens has positive refractive power, and the seventh lens has negative refractive power, wherein the first and second lenses are a first lens group which is a fixed group, the third to fifth lenses are a second lens group which is a fixed group, and the sixth to seventh lenses are a third lens group which is a moving group.

[0022] The first lens group may have positive (+) refractive power, the second lens group may have positive (+) refractive power, and the third lens group may have negative (-) refractive power.

[0023] In the above optical axis, the first lens may have a meniscus shape convex toward the object side.

[0024] The object-side surface of the third lens on the optical axis may have a convex shape, and the fourth lens on the optical axis may have a meniscus shape convex toward the object side.

[0025] The following condition can be satisfied. <Condition> 0.5 < CG1 < 1.3 (In the above condition, CG1 is the center distance between the first lens and the second lens.)

[0026] The following condition can be satisfied. <Condition> 0.5 < CG2 < 5.5 (In the above condition, CG2 is the center distance between the second lens and the third lens.)

[0027] The optical system and camera module according to the present embodiment have various magnifications and can exhibit excellent optical characteristics when providing various magnifications. Specifically, the embodiment can control a lens group having a set number of lenses, a set refractive power, a plurality of lenses having set shapes and focal lengths, etc., a moving distance of a moving lens group, etc. to have various magnifications and can provide an autofocus (AF) function for the subject.

[0028] Additionally, each of the plurality of lens groups can compensate for aberration characteristics or mutually complement aberration characteristics that change with movement. Accordingly, the optical system according to the embodiment can minimize or prevent changes in chromatic aberration and aberration characteristics that occur when magnification changes.

[0029] Additionally, the effective focal length (EFL) can be controlled by moving only some of the lens groups among the plurality of lens groups, thereby minimizing the distance traveled by the moving lens groups. Accordingly, the embodiment can significantly reduce the distance traveled by the lens groups when the magnification changes, and minimize the power consumption required when moving the lens groups.

[0030] In addition, the optical system according to the present embodiment has improved optical characteristics and can have a large BFL (Back focal length), so that it can provide an optical system suitable for a folded camera module.

[0031] Figure 1 is a configuration diagram of an optical system according to the first embodiment operating in the first mode.

[0032] Figure 2 is a configuration diagram of an optical system according to the first embodiment operating in the second mode.

[0033] Figure 3 is a table showing the aspherical coefficients of lenses in the optical system according to the first embodiment.

[0034] Fig. 4 is a graph showing data on aberration characteristics of an optical system according to the first embodiment operating in the first mode.

[0035] Figure 5 is a configuration diagram of an optical system according to the second embodiment operating in the first mode.

[0036] Figure 6 is a configuration diagram of an optical system according to the second embodiment operating in the second mode.

[0037] Figure 7 is a table showing the aspherical coefficients of lenses in the optical system according to the second embodiment.

[0038] Fig. 8 is a graph showing data on aberration characteristics of an optical system according to the second embodiment operating in the first mode.

[0039] Figure 9 is a configuration diagram of an optical system according to the third embodiment operating in the first mode.

[0040] Fig. 10 is a configuration diagram of an optical system according to the third embodiment operating in the second mode.

[0041] Fig. 11 is a table showing the aspherical coefficients of lenses in the optical system according to the third embodiment.

[0042] Fig. 12 is a graph showing data on aberration characteristics of an optical system according to the third embodiment operating in the first mode.

[0043] Fig. 13 is a configuration diagram of an optical system according to the fourth embodiment operating in the first mode.

[0044] Fig. 14 is a configuration diagram of an optical system according to the fourth embodiment operating in the second mode.

[0045] Fig. 15 is a table showing the aspherical coefficients of lenses in the optical system according to the fourth embodiment.

[0046] Fig. 16 is a graph showing data on aberration characteristics of an optical system according to the fourth embodiment operating in the first mode.

[0047] Fig. 17 is a drawing for explaining the D-cut lens of the present invention.

[0048] Fig. 18 is an example of a portable terminal having an optical system according to the present embodiment.

[0049] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings.

[0050] However, the technical idea of ​​the present invention is not limited to some of the embodiments described, but can be implemented in various different forms, and within the scope of the technical idea of ​​the present invention, one or more of the components between the embodiments can be selectively combined or substituted for use.

[0051] In addition, terms (including technical and scientific terms) used in this embodiment may be interpreted as having a meaning that can be generally understood by a person of ordinary skill in the technical field to which this embodiment belongs, unless explicitly and specifically defined and described, and terms that are commonly used, such as terms defined in a dictionary, may be interpreted in consideration of the contextual meaning of the relevant technology.

[0052] Additionally, the terms used in this embodiment are for the purpose of describing the embodiments and are not intended to limit the present invention.

[0053] In this specification, the singular may also include the plural unless specifically stated otherwise in the phrase, and when it is described as “A and / or at least one (or more) of B, C”, it may include one or more of all combinations that can be combined with A, B, C.

[0054] Additionally, in describing the components of this embodiment, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only intended to distinguish the components from other components, and are not intended to limit the nature, order, or sequence of the components.

[0055] And, when a component is described as being 'connected', 'coupled', or 'connected' to another component, it may include not only cases where the component is 'connected', 'coupled', or 'connected' directly to the other component, but also cases where the component is 'connected', 'coupled', or 'connected' by another component between the component and the other component.

[0056] Additionally, when described as being formed or arranged "above" or "below" each component, "above" or "below" includes not only cases where the two components are in direct contact with each other, but also cases where one or more other components are formed or arranged between the two components. Furthermore, when expressed as "above" or "below," the meaning may include not only the upward direction but also the downward direction based on one component.

[0057] In the description of the invention, the "object side" may mean a surface of the lens facing the object side with respect to the optical axis (OA), and the "sensor side" may mean a surface of the lens facing the imaging surface (image sensor) with respect to the optical axis. The "object side" may be the "object side," and the "sensor side" may be the "image side." A convex surface of a lens may mean a convex shape in the optical axis or the paraxial region, and a concave surface of a lens may mean a concave shape in the optical axis or the paraxial region. The radius of curvature, the center thickness, and the optical axis spacing between lenses described in the table for lens data may mean values ​​(unit: mm) in the optical axis. The vertical direction may mean a direction perpendicular to the optical axis, and the end of a lens or lens surface may mean the end of an effective area of ​​a lens through which incident light passes. The size of the effective diameter of the lens surface may have a measurement error of up to ±0.4 mm depending on the measurement method, etc. The above-mentioned near-axis region refers to a very narrow region near the optical axis, and is a region where the distance that a light ray falls from the optical axis (OA) is almost 0. Hereinafter, the meaning of the optical axis may include the center of each lens or a very narrow region near the optical axis.

[0058] The optical axis (OA) may refer to the central axis on the path of light along which light incident from a second direction (Y-axis direction) by a prism lens is bent into a first direction (X-axis direction).

[0059]

[0060] The optical systems (1000 to 1300: 1000, 1100, 1200, 1300) according to the first to fourth embodiments may include a plurality of lens groups. In detail, the optical systems (1000 to 1300) may include a plurality of lens groups each including at least one lens. For example, the optical systems (1000 to 1300) may include a first lens group (LG1), a second lens group (LG2), a third lens group (LG3), and an image sensor (500) that are sequentially arranged from the object side toward the image sensor.

[0061] The first to third lens groups (LG1, LG2, LG3) may each have positive (+) or negative (-) refractive power. The first lens group (LG1) and the second lens group (LG2) may have refractive powers of the same sign, and the second lens group (LG2) and the third lens group (LG3) may have refractive powers of different signs. For example, the first lens group (LG1) and the second lens group (LG2) may have positive (+) refractive power, and the third lens group (LG3) may have negative (-) refractive power.

[0062]

[0063] At least one of the first lens group (LG1), the second lens group (LG2), and the third lens group (LG3) may be provided to be movable in the direction of the optical axis (OA). For example, the first lens group (LG1) and the second lens group (LG2) may be fixed, and the third lens group (LG3) may be provided to be movable. The first lens group (LG1) and the second lens group (LG2) may be arranged at a fixed position, and the third lens group (LG3) may be provided to be movable in the direction of the optical axis (OA).

[0064]

[0065] The first lens group (LG1) may include multiple lenses. Specifically, the first lens group (LG1) may include prism lenses (102 to 402: 102, 202, 302, 402). For example, the first lens group (LG1) may include two lenses.

[0066] The plurality of lenses included in the first lens group (LG1) may have a set interval. Specifically, the interval between the plurality of lenses included in the first lens group (LG1) may be constant and not change in the operation mode described later. For example, the interval between the first lenses (101 to 401: 101, 201, 301, 401) and the second lenses (102 to 402) may be constant and not change in the operation mode described later.

[0067] The first lens group (LG1) may include a prism lens. The optical system (1000 to 1300) may reduce the first direction (X-axis direction) and the second direction (Y-axis direction) of the optical system (1000 to 1300) by including the second lens (102 to 402) which is a prism lens. When the optical system (1000 to 1300) does not include a prism lens, a plurality of lenses may be arranged to extend in a direction perpendicular to a surface of the optical device within the optical device including the optical system (1000 to 1300).

[0068] Accordingly, the plurality of lenses have a high height in a direction perpendicular to the surface of the optical device, and it may be difficult to form the optical device with an ultra-thin thickness. The prism lens can change light incident in a direction perpendicular to the plane of the optical device into a direction parallel to the surface of the optical device. That is, the plurality of lenses included in the optical system (1000 to 1300) can be arranged to extend in a direction parallel to the surface of the optical device, and the optical device can be formed with a thin thickness.

[0069] A driving member (not shown) may be connected to a prism lens. The driving member may include at least one actuator. For example, the driving member may include at least one of a voice coil motor (VCM), a piezoelectric device, a shape memory alloy, and a MEMS device as an actuator. The driving member may move the prism lens using the driving force of the actuator. For example, the driving member may tilt-control the prism lens along a first axis (X-axis) or a second axis (Y-axis). Accordingly, the camera module (1520) may compensate for shaking.

[0070] It includes a sensing unit (not shown) that detects the shaking of the camera module (1520), and the sensing unit can detect rotation and position changes applied to the camera module (1520). The sensing unit can include at least one of a sensor that detects a change in angular velocity, for example, a gyro sensor, and an acceleration sensor that detects a change in acceleration.

[0071] The camera module (1520) can control the movement of the prism lens by a control signal. Specifically, when shaking occurs in the camera module (1520), information about the shaking, such as the degree of rotation and position change of the sensors, can be detected, and compensation for the shaking can be performed.

[0072] Accordingly, the camera module (1520) according to the embodiment can effectively compensate for rotational shaking and positional shaking when photographing a subject located at infinity or close range (macro). Accordingly, the camera module (1520) can have improved optical characteristics.

[0073]

[0074] The second lens group (LG2) may include multiple lenses. Specifically, the second lens group (LG2) may include three or more lenses having opposite refractive powers. The number of lenses included in the second lens group (LG2) may be greater than the number of lenses included in the first lens group (LG1). For example, the second lens group (LG2) may include three lenses.

[0075] The plurality of lenses included in the second lens group (LG2) may have a set interval. In detail, the interval between the plurality of lenses included in the second lens group (LG2) may be constant without changing in the operation mode described later. For example, the interval between the third lens (103 to 403: 103, 203, 303, 403) and the fourth lens (104 to 404: 104, 204, 304, 404) and the interval between the fourth lens (104 to 404) and the fifth lens (105 to 705: 105, 205, 305, 405) may be constant without changing in the operation mode described later.

[0076] The third lens group (LG3) may include multiple lenses. Specifically, the third lens group (LG3) may include two or more lenses having opposite refractive powers. For example, the third lens group (LG3) may include two lenses.

[0077] The plurality of lenses included in the third lens group (LG3) may have a set interval. Specifically, the interval between the plurality of lenses included in the third lens group (LG3) may be constant and not change in the operation mode described later. For example, the interval between the sixth lens (106 to 406: 106, 206, 306, 406) and the seventh lens (107 to 407: 107, 207, 307, 407) may be constant and not change in the operation mode described later.

[0078]

[0079] The optical system (1000 to 1300) may include a plurality of lens groups (LG1, LG2, LG3) and an image sensor (500) sequentially arranged from the object side toward the sensor. In addition, the optical system (1000 to 1300) may include a plurality of lenses included in the lens groups (LG1, LG2, LG3), for example, a first lens (101 to 401), a second lens (102 to 402), a third lens (103 to 403), a fourth lens (104 to 404), a fifth lens (105 to 405), a sixth lens (106 to 406), and a seventh lens (107 to 407).

[0080] The first lens group (LG1) may include a first lens (101 to 401) and a second lens (102 to 402). The second lens group (LG2) may include a third lens (103 to 403), a fourth lens (104 to 404), and a fifth lens (105 to 405). The third lens group (LG3) may include a sixth lens (106 to 406) and a seventh lens (107 to 407). The first to seventh lenses (101 to 107 to 401 to 407) and the image sensor (500) may be sequentially arranged along the optical axis (OA) of the optical system (1000 to 1300).

[0081] Each of the plurality of lenses may include an effective area and an ineffective area. The effective area may be an area through which light incident on each of the first to seventh lenses (101-107 to 401-407) passes. In other words, the effective area may be an area in which the incident light is refracted to implement optical characteristics.

[0082] The inactive area may be located around the active area. The inactive area may be an area where no light is incident. In other words, the inactive area may be an area unrelated to optical properties. Additionally, the inactive area may be an area fixed to a barrel (not shown) that accommodates the lens.

[0083] Referring to FIG. 17, at least one of the first to seventh lenses (101-107 to 401-407) in the optical systems (1000 to 1300) according to the first to fourth embodiments may be subject to the D-cut technique. When the D-cut technique is applied, the height of the entire optical system may be reduced by cutting a portion of the lens effective diameter or rib. Here, the height of the entire optical system may mean the length in the direction perpendicular to the optical axis rather than the TTL. The D-cut lens may have a non-circular shape, and the length (A) in the second direction (Y-axis direction) and the length (B) in the first direction (X-axis direction) may be different.

[0084]

[0085] The image sensor (500) can detect light. The image sensor (500) can detect light that has sequentially passed through a plurality of lenses, for example, the first to seventh lenses (101-107 to 401-407). The image sensor (500) may include a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor).

[0086] The optical system (1000 to 1300) may further include a filter (600). The filter (600) may be arranged between a plurality of lenses and the image sensor (500). The filter (600) may be arranged between the third lens group (LG3) closest to the image sensor (500) among the plurality of lens groups (LG1, LG2, LG3) and the image sensor (500). For example, the filter (600) may be arranged between the seventh lens (107 to 707), which is the last lens of the third lens group (LG3) closest to the image sensor (500) among the plurality of lenses, and the image sensor (500).

[0087] The filter (600) may include at least one optical filter, such as an infrared filter or a cover glass. The filter (600) may allow light of a set wavelength band to pass through and filter out light of a different wavelength band. When the filter (600) includes an infrared filter, it may block radiant heat emitted from external light from being transmitted to the image sensor (500). In addition, the filter (600) may transmit visible light and reflect infrared light.

[0088] The optical system (1000-1300) may include an aperture (not shown). The aperture can control the amount of light incident on the optical system (1000-1300).

[0089] The aperture may be positioned in front of the first lens (101 to 401) or may be arranged between two lenses selected from the first to seventh lenses (101 to 107 to 401 to 407). For example, the aperture may be arranged between the second lens (102 to 402) and the third lens (103 to 403). In addition, at least one lens selected from the first to seventh lenses (101 to 107 to 401 to 407) may function as an aperture. For example, the object-side surface or the sensor-side surface of one lens selected from the first to seventh lenses (101 to 107 to 401 to 407) may function as an aperture for controlling the amount of light.

[0090]

[0091] An optical system according to the first embodiment of the invention will be described.

[0092] FIG. 1 is a configuration diagram of an optical system according to the first embodiment of the present invention operating in the first mode, FIG. 2 is a configuration diagram of an optical system according to the first embodiment of the present invention operating in the second mode, FIG. 3 is a table showing aspherical coefficients of lenses in the optical system according to the first embodiment of the present invention, and FIG. 4 is a graph showing data on aberration characteristics of the optical system according to the first embodiment of the present invention operating in the first mode.

[0093] Referring to FIG. 1, the optical system (1000) includes a lens unit, and the lens unit may include first to seventh lenses (101 to 107). The first to seventh lenses (101 to 107) may be sequentially arranged along the optical axis (OA) of the optical system (1000). Light corresponding to information about an object may pass through the first to seventh lenses (101 to 107) and a filter (600) and be incident on the image sensor (500).

[0094] The first lens (101) may be positioned closest to the object side. The first lens (101) may be positioned furthest from the sensor side. The first lens (101) may have positive refractive power. The first lens (101) may include a plastic or glass material. For example, the first lens (101) may be provided as a plastic material.

[0095] The first surface (S1) on the object side of the first lens (101) may be convex with respect to the optical axis, and the second surface (S2) on the sensor side may be concave. The first lens (101) may have a meniscus shape in which the object side is convex. The first lens (101) may have a meniscus shape in which the sensor side is concave. The first lens (101) is made of a plastic material and may have an aspherical surface. The aspherical coefficients of the first surface (S1) and the second surface (S2) of the first lens (101) may be provided as L1S1 and L1S2 of FIG. 3. At least one or both of the first surface (S1) and the second surface (S2) of the first lens (101) may be provided without a critical point from the optical axis to the end of the effective area.

[0096]

[0097] The second lens (102) may be a prism lens. The second lens (102) may be a right-angle prism lens. The second lens (102) may be a light path control member. The second lens (102) can change the path of light incident from the outside. The second lens (102) may include a reflector and a prism. The second lens (102) can rotate the light path by 90 degrees. The second lens (102) includes an incident surface (S3) on which light is incident, a reflective surface (RS1) that reflects the incident light, and an exit surface (S4) that emits the reflected light. The reflective surface (RS1) has an inclination angle of 45 degrees and reflects the principal ray of the incident light at 90 degrees, thereby reflecting the incident light to the third lens (103). The second lens (102) can reflect light incident in the second direction (Y-axis direction) and change the path of the light to the first direction (X-axis direction).

[0098] The aperture (STOP) may be positioned between the second lens (102) and the third lens (103). The aperture may be positioned on the fourth surface (S4) on the sensor side of the second lens (102) or the fifth surface (S5) on the object side of the third lens (103). The aperture can reduce the TTL within the field of view range and enable miniaturization of the optical system. Accordingly, a decrease in the yield by weight of the optical system can be prevented and production efficiency can be improved.

[0099]

[0100] The third lens (103) may be arranged third from the object side. The third lens (103) may be arranged fifth from the sensor side. The third lens (103) may be arranged between the second lens (102) and the fourth lens (104). The third lens (103) may have positive (+) refractive power. The third lens (103) may include a plastic or glass material. For example, the third lens (103) may be provided as a plastic material.

[0101] The fifth surface (S5) on the object side of the third lens (103) may be convex with respect to the optical axis, and the sixth surface (S6) on the sensor side may be concave. The third lens (103) may have a meniscus shape in which the object side is convex. The third lens (103) may have a meniscus shape in which the sensor side is concave. The third lens (103) is made of a plastic material and may have an aspherical surface. The aspherical coefficients of the fifth surface (S5) and the sixth surface (S6) may be provided as L3S1 and L3S2 of FIG. 3. At least one or both of the fifth surface (S5) and the sixth surface (S6) of the third lens (103) may be provided without a critical point from the optical axis to the end of the effective area.

[0102]

[0103] The fourth lens (104) may be arranged fourth from the object side. The fourth lens (104) may be arranged fourth from the sensor side. The fourth lens (104) may be arranged between the third lens (103) and the fifth lens (105). The fourth lens (104) may have negative (-) refractive power. The fourth lens (104) may include a plastic or glass material. For example, the fourth lens (104) may be provided as a plastic material.

[0104] The seventh surface (S7) on the object side of the fourth lens (104) may be convex with respect to the optical axis, and the eighth surface (S8) on the sensor side may be concave. The fourth lens (104) may have a meniscus shape in which the object side is convex. The fourth lens (104) may have a meniscus shape in which the sensor side is concave. The fourth lens (104) is made of a plastic material and may have an aspherical surface. The aspherical coefficients of the seventh surface (S7) and the eighth surface (S8) may be provided as L4S1 and L4S2 of FIG. 3. At least one or both of the seventh surface (S7) and the eighth surface (S8) of the fourth lens (104) may be provided without a critical point from the optical axis to the end of the effective area.

[0105]

[0106] The fifth lens (105) may be arranged as the fifth lens from the object side. The fifth lens (105) may be arranged as the third lens from the sensor side. The fifth lens (105) may be arranged between the fourth lens (104) and the sixth lens (106). The fifth lens (105) may have positive (+) refractive power. The fifth lens (105) may include a plastic or glass material. For example, the fifth lens (105) may be provided as a plastic material.

[0107] With respect to the optical axis (OA), the ninth surface (S9) on the object side of the fifth lens (105) may be convex, and the tenth surface (S10) on the sensor side may be convex. The fifth lens (105) may have a shape in which both sides are convex. The fifth lens (105) is made of a plastic material and may have an aspherical surface. The aspherical coefficients of the ninth surface (S9) and the tenth surface (S10) may be provided as L5S1 and L5S2 of FIG. 3.

[0108] The ninth surface (S9) of the fifth lens (105) may have a critical point from the optical axis to the end of the effective area. When the ninth surface (S9) has a critical point, it may be located in a range of 60% to 80%, preferably in a range of 65% to 70%, of the effective radius from the optical axis. The critical point of the ninth surface (S9) may be located in a range of 1.0 mm to 2.5 mm, preferably in a range of 1.5 mm to 2.0 mm from the optical axis. The critical point of the ninth surface (S9) may be a point where the sign of the gradient value with respect to the optical axis and the direction perpendicular to the optical axis changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the gradient value is 0. In addition, the critical point of the ninth surface (S9) may be a point where the gradient value of a tangent passing through the lens surface increases and then decreases, or a point where the gradient value decreases and then increases. The tenth surface (S10) of the fifth lens (105) can be provided without a critical point from the optical axis to the end of the effective area.

[0109]

[0110] The sixth lens (106) may be arranged as the sixth lens from the object side. The sixth lens (106) may be arranged as the second lens from the sensor side. The sixth lens (106) may be arranged between the fifth lens (105) and the seventh lens (107). The sixth lens (106) may have positive (+) refractive power. The sixth lens (106) may include a plastic or glass material. For example, the sixth lens (106) may be provided as a plastic material.

[0111] With respect to the optical axis (OA), the eleventh surface (S11) on the object side of the sixth lens (106) may be concave, and the twelfth surface (S12) on the sensor side may be convex. The sixth lens (106) may have a meniscus shape in which the object side is concave. The sixth lens (106) may have a meniscus shape in which the sensor side is convex. The sixth lens (106) is made of a plastic material and may have an aspherical surface. The aspherical coefficients of the eleventh surface (S11) and the twelfth surface (S12) may be provided as L6S1 and L6S2 of FIG. 3. At least one or both of the eleventh surface (S11) and the twelfth surface (S12) of the sixth lens (106) may be provided without a critical point from the optical axis to the end of the effective area.

[0112]

[0113] The seventh lens (107) may be arranged closest to the sensor side. The seventh lens (107) may be arranged farthest from the object side. The seventh lens (107) may be arranged between the sixth lens (106) and the filter (600). The seventh lens (107) may be arranged between the sixth lens (106) and the image sensor (500). The seventh lens (107) may have negative (-) refractive power. The seventh lens (107) may include a plastic or glass material. For example, the seventh lens (107) may be provided with a plastic material.

[0114] With respect to the optical axis (OA), the 13th surface (S13) on the object side of the seventh lens (107) may be concave, and the 14th surface (S14) on the sensor side may be concave. The seventh lens (107) may have a shape in which both sides are concave. The seventh lens (107) may be made of a plastic material and may have an aspherical surface. The aspherical coefficients of the 13th surface (S13) and the 14th surface (S14) may be provided as L7S1 and L7S2 of FIG. 3.

[0115] The 13th surface (S13) of the seventh lens (107) may be provided without a critical point from the optical axis to the end of the effective area. The 14th surface (S14) of the seventh lens (107) may have a critical point from the optical axis to the end of the effective area. When the 14th surface (S14) has a critical point, it may be located in a range of 45% to 65%, preferably 50% to 60%, of the effective radius from the optical axis. The critical point of the 14th surface (S14) may be located in a range of 1.0 mm to 2.5 mm, preferably 1.5 mm to 2.0 mm from the optical axis. The critical point of the 14th surface (S14) is a point where the sign of the gradient value with respect to the optical axis and the direction perpendicular to the optical axis changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the gradient value is 0. Additionally, the critical point of the 14th surface (S14) may be a point where the slope value of the tangent line passing through the lens surface increases and then decreases, or a point where the slope value decreases and then increases.

[0116]

[0117] LensSurfaceRadiusThicknessndvdClearAperture1S18.1201.4301.55056.0007.800 S212.0001.070 7.3202S3Infinity6.6001.72029.5007.230STOPS4Infinity1.200 6.3303S54.8900.9801.55056.0005.820 S614.3100.300 5.6404S78.6801.2001.68019.2005.550 S83.1802.180 4.9605S965.3002.7501.68019.2005.420S10-7.340Variable(D1) 5.8806S11-5.1701.4901.55056.0005.880 S12-3.8500.260 6.2507S13-13.1002.2401.68019.2005.850 S1415.990Variable(D2) 6.780Filter Infinity Infinity Image Infinity

[0118] Table 1 shows the surface number (Surface), radius of curvature (Radius), center thickness of each lens or distance between lens surfaces (Thickness), refractive index (Index,nd), Abbe number (Abbe,vd), clear aperture, and focal length of the lens according to the first embodiment of the present invention. At this time, the unit of the radius of curvature and thickness or distance may be mm.

[0119] In Table 1, the thickness of the second lens (102), which is a prism lens, may refer to the thickness along the optical axis (OA). For example, the thickness of the second lens (102) may refer to the sum of the thickness from the object side (S3) to the reflective surface (RS1) on the y-axis and the thickness from the reflective surface (RS1) to the sensor side (S4) on the x-axis. In addition, the thickness of the second lens (102) from the object side (S3) to the reflective surface (RS1) on the y-axis and the thickness of the second lens (102) from the reflective surface (RS1) to the sensor side (S4) on the x-axis may be the same. According to a variation, the thickness of the second lens (102) from the object side (S3) to the reflective surface (RS1) on the y-axis and the thickness of the second lens (102) from the reflective surface (RS1) to the sensor side (S4) on the x-axis may be different.

[0120]

[0121] Mode 1 Mode 2 D11.6802.250 D26.1005.530

[0122] Table 2 shows the distances (D1, D2) between lenses that are variable when the optical system according to the first embodiment of the present invention operates in one of the first and second modes. Here, the first mode may refer to a case where an object located at infinity is photographed, and the second mode may refer to a case where an object located at a close range (macroscopic) (e.g., within 1000 mm) is photographed.

[0123] In the optical system according to the first embodiment of the present invention, the distance between adjacent lens groups may change during the process of changing the magnification from the first mode to the second mode. The first and second lens groups (LG1, LG2) may be fixed, and the third lens group (LG3) may be movable. The first and second lens groups (LG1, LG2) may be fixed groups, and the third lens group (LG3) may be a movable group.

[0124] When operating from the first mode to the second mode, the distance (D1) between the second lens group (LG2) and the third lens group (LG3) may increase, and the distance (D2) between the third lens group (LG3) and the image sensor (500) may decrease.

[0125] When operating from the second mode to the first mode, the distance (D1) between the second lens group (LG2) and the third lens group (LG3) may decrease, and the distance (D2) between the third lens group (LG3) and the image sensor (500) may increase.

[0126] The stroke length of the third lens group (LG3) can satisfy 0.3 mm to 0.8 mm, and preferably, can satisfy about 0.570 mm.

[0127]

[0128] EFL(F)20.750EPD7.800BFL_16.100SD13.080BFL_25.530TD23.380FOV_121.900TD_LG19.100FOV_222.000TD_LG27.410 f140.690TD_LG33.990f2-f_LG140.690f313.120f_LG215.090f4-8.120f_LG3-19.070f59.870LG3_stroke0.570f619.8 20TTL29.480f7-10.290ImgH8.200ET10.980ΣCT16.690ET26.600ΣCG6.690ET30.410CA_Max7.560ET41.760CA_Min5.255 ET52.090CA_Aver6.194ET60.900L_CT_max6.600ET72.920L_CT_min0.980Fno2.700L_CT_aver2.384TL_Y5.8TL_X23.68

[0129] Table 3 shows the items of the mathematical formulas described above in the optical system (1000) of the present embodiment, including the effective focal length (EFL (F) (mm)) in the first mode of the optical system (1000), the distance from the sensor side of the last lens to the image sensor (BFL_1 (mm)) in the first mode, the distance from the sensor side of the last lens to the image sensor (BFL_2 (mm)) in the second mode, the angle of view (FOV_1 (degree)) in the first mode, the angle of view (FOV_2 (degree)) in the second mode, the focal lengths (f1 to f7) (mm) of the first to seventh lenses (101 to 107), the edge thickness (ET1 to ET7), the lengths of each lens group (TD_LG1, TD_LG2, TD_LG3) in the optical axis direction, the focal lengths (f_LG1, f_LG2, f_LG3) (mm) of the first to third lens groups (LG1, LG2, LG3), The size of the entrance pupil (EPD (mm)), the optical axis distance (SD (mm)) from the aperture (STOP) to the 14th surface (S14), the optical axis distance (TD (mm)) from the first lens (101) to the seventh lens (107), the brightness (Fno) of the optical system (1000), the stroke length (LG3_stroke) of the third lens group (LG3), the total optical axis distance of the optical system (1000) TTL (mm), ImgH (mm), the maximum effective diameter (CA_Max), the minimum effective diameter (CA_Min), the average effective diameter (CA_Aver), the maximum center thickness (L_CT_max), the minimum center thickness (L_CT_min), the average center thickness (L_CT_aver) among the first to seventh lenses (101 to 107), the length in the Y-axis direction (TL_Y) of the optical system (1000), the length in the X-axis direction (TL_X) of the optical system (1000), etc.

[0130]

[0131] Hereinafter, the center thicknesses of the first to seventh lenses (101 to 107) are represented as CT1 to CT7, the edge thicknesses at the ends of the effective areas of each lens are represented as ET1 to ET7, and the center gap between two adjacent lenses is represented as CG1 to CG6. The back focal length (BFL) is the optical axis distance from the image sensor (500) to the center of the last lens. The TTL is the optical axis distance from the center of the first surface (S1) of the first lens (101) to the upper surface of the image sensor (500).

[0132]

[0133] When comparing the absolute values ​​of the curvature radii of each lens, the curvature radii of the ninth surface (S9) of the fifth lens (105) on the optical axis (OA) may be the largest among the lenses, and the curvature radii of the eighth surface (S8) of the fourth lens (104) may be the smallest among the lenses. The absolute value of the curvature radii of the first surface (S1) of the first lens (101) may be smaller than the absolute value of the curvature radii of the second surface (S2). The absolute value of the curvature radii of the fifth surface (S5) of the third lens (103) may be smaller than the absolute value of the curvature radii of the sixth surface (S6). The absolute value of the curvature radii of the seventh surface (S7) of the fourth lens (104) may be larger than the absolute value of the curvature radii of the eighth surface (S8). The absolute value of the curvature radius of the ninth surface (S9) of the fifth lens (105) may be greater than the absolute value of the curvature radius of the tenth surface (S10). The absolute value of the curvature radius of the eleventh surface (S11) of the sixth lens (106) may be greater than the absolute value of the curvature radius of the twelfth surface (S12). The absolute value of the curvature radius of the thirteenth surface (S13) of the seventh lens (107) may be less than the absolute value of the curvature radius of the fourteenth surface (S14).

[0134]

[0135] Condition 1: 0.5 < |L1R1 / L1R2| < 1

[0136] Condition 2: 0.1 < |L3R1 / L3R2| < 0.5

[0137] Condition 3: 2.5 < |L4R1 / L4R2| < 3

[0138] Condition 4: 5 < |L5R1 / L5R2| < 10

[0139] Condition 5: 1 < |L6R1 / L6R2| < 1.5

[0140] Condition 6: 0.5 < |L7R1 / L7R2| < 1

[0141]

[0142] When describing the central thickness of the lenses based on the optical axis, the central thickness (CT2) of the second lens (102) is the largest among the lenses, and the central thickness (CT3) of the third lens (103) is the smallest among the lenses. The difference between the maximum and minimum central thicknesses among the lenses may be in the range of 5 mm or more and 6 mm or less.

[0143] The central thickness of each lens may satisfy any one of the following conditions:

[0144] Condition 1: CT2, CT5, CT6, CT7 > CT1 > CT3, CT4

[0145] Condition 2: CT2 > CT1, CT3, CT4, CT5, CT6, CT7

[0146] Condition 3: CT1, CT2, CT4, CT5, CT6, CT7 > CT3

[0147] Condition 4: CT1, CT2, CT5, CT6, CT7 > CT4 > CT3

[0148] Condition 5: CT2 > CT5 > CT1, CT3, CT4, CT6, CT7

[0149] Condition 6: CT2, CT5, CT7 > CT6 > CT1, CT3, CT4

[0150] Condition 7: CT2, CT5 > CT7 > CT1, CT3, CT4, CT6

[0151]

[0152] When zooming, the distance (CG1) between the first lens (101) and the second lens (102), the distance (CG2) between the second lens (102) and the third lens (103), the distance (CG3) between the third lens (103) and the fourth lens (104), the distance (CG4) between the fourth lens (104) and the fifth lens (105), and the distance (CG6) between the sixth lens (106) and the seventh lens (107) do not change, but the distance (CG5) between the fifth lens (105) and the sixth lens (106) can change. Among the center distances between the lenses that do not change, the distance (CG4) between the fourth lens (104) and the fifth lens (105) can be the maximum, and the distance (CG6) between the sixth lens (106) and the seventh lens (107) can be the minimum. The difference between the maximum center spacing and the minimum center spacing among the lens spacings may be 1.5 mm or more, for example, in the range of 1.5 mm to 2.0 mm.

[0153] The center spacing between each lens can satisfy the conditions below.

[0154] Condition 1: CG2, CG4 > CG1 > CG3, CG6

[0155] Condition 2: CG4 > CG2 > CG1, CG3, CG6

[0156] Condition 3: CG1, CG2, CG4 > CG3 > CG6

[0157] Condition 4: CG4 > CG1, CG2, CG3, CG6

[0158] Condition 5: CG1, CG2, CG3, CG4 > CG6

[0159]

[0160] Regarding the effective diameter, the lens having the maximum effective diameter may be the first lens (101). Here, the effective diameter is the average of the effective diameters of the object-side surface and the sensor-side surface of each lens. The lens surface having the maximum effective diameter may be the first surface (S1) of the first lens (101). The lens having the minimum effective diameter may be the fourth lens (104). The lens surface having the minimum effective diameter may be the eighth surface (S8) of the fourth lens (104). The effective diameters of the first to seventh lenses (101-107) may be smaller than the diagonal length of the image sensor (500).

[0161] The effective diameter of each lens can satisfy any one of the conditions below.

[0162] Condition 1: CA_L1 > CA_L2, CA_L3, CA_L4, CA_L5, CA_L6, CA_L7

[0163] Condition 2: CA_L1 > CA_L2 > CA_L3, CA_L4, CA_L5, CA_L6, CA_L7

[0164] Condition 3: CA_L1, CA_L2, CA_L6, CA_L7 > CA_L3 > CA_L4, CA_L5

[0165] Condition 4: CA_L1, CA_L2, CA_L3, CA_L5, CA_L6, CA_L7 > CA_L4

[0166] Condition 5: CA_L1, CA_L2, CA_L3, CA_L6, CA_L7 > CA_L5 > CA_L4

[0167] Condition 6: CA_L1, CA_L2, CA_L7 > CA_L6 > CA_L3, CA_L4, CA_L5

[0168] Condition 7: CA_L1, CA_L2 > CA_L7 > CA_L3, CA_L4, CA_L5, CA_L6

[0169]

[0170] In terms of refractive index, the refractive index of the second lens (102) may be the highest among the lenses and may be greater than 1.6, for example, greater than 1.7. Any one of the first lens (101), the third lens (103), and the sixth lens (106) may have the lowest refractive index among the lenses. For example, the refractive index of any one of the first lens (101), the third lens (103), and the sixth lens (106) may be the lowest among the lenses and may be less than 1.6, for example, less than 1.57. The difference between the maximum refractive index and the minimum refractive index may be 0.1 or more.

[0171] The refractive index of each lens can satisfy any of the conditions below.

[0172] Condition 1: n2, n4, n5, n7 > n1 = n3 = n6

[0173] Condition 2: n2 > n1, n3, n4, n5, n6, n7

[0174] Condition 3: n2 > n4 = n5 = n7 > n1, n3, n6

[0175]

[0176] Comparing the Abbe numbers, the Abbe numbers of the first lens (101), the third lens (103), and the sixth lens (106) are the largest among the lenses and may be 50 or more. The Abbe numbers of the fourth lens (104), the fifth lens (105), and the seventh lens (107) are the smallest among the lenses and may be 20 or less. The difference between the maximum refractive index and the minimum Abbe number may be 30 or more.

[0177] The Abbe number of each lens can satisfy any of the conditions below.

[0178] Condition 1: v1 = v3 = v6 > v2, v4, v5, v7

[0179] Condition 2: v1, v3, v6 > v2 > v4, v5, v7

[0180] Condition 3: v1, v2, v3, v6 > v4 = v5 = v7

[0181]

[0182] The focal lengths (F1, F3, F5, F6) of the first, third, fifth, and sixth lenses (101, 103, 105, and 106) may have a positive (+) sign. The first, third, fifth, and sixth lenses (101, 103, 105, and 106) may have a positive (+) refractive power. The focal lengths (F4, F7) of the fourth and seventh lenses (104, 107) may have a negative (-) sign. The fourth and seventh lenses (104, 107) may have a negative (-) refractive power. When comparing the focal lengths in absolute values, the focal length of the first lens (101) is the largest among the lenses and may be 30 or more and 40 or less. The focal length of the seventh lens (107) is the smallest among the lenses, and the absolute value of the focal length of the seventh lens (107) may be 8 or more and 10 or less.

[0183] The absolute value of the focal length of each lens can satisfy any of the conditions below.

[0184] Condition 1: |f1| > |f3|, |f4|, |f5|, |f6|, |f7|

[0185] Condition 2: |f1|, |f6| > |f3| > |f4|, |f5|, |f7|

[0186] Condition 3: |f1|, |f3|, |f5|, |f6|, |f7| > |f4|

[0187] Condition 4: |f1|, |f3|, |f6|, |f7| > |f5| > |f4|

[0188] Condition 5: |f1| > |f6| > |f3|, |f4|, |f5|, |f7|

[0189] Condition 6: |f1|, |f3|, |f6| > |f7| > |f4|, |f5|

[0190]

[0191] The composite focal length (f_LG1) of the first lens group (LG1) can have a positive (+) sign. The first lens group (LG1) can have a positive (+) composite refractive power. The composite focal length (f_LG2) of the second lens group (LG2) can have a positive (+) sign. The second lens group (LG2) can have a positive (+) composite refractive power. The composite focal length (f_LG3) of the third lens group (LG3) can have a negative (-) sign. The third lens group (LG3) can have a negative (-) composite refractive power. Through this, light incident from the object side can move away from the optical axis direction and then gather again in the optical axis direction, thereby forming a stable optical path.

[0192] When comparing the absolute values ​​of the composite focal lengths of the first to third lens groups (LG1, LG2, LG3), the composite focal length of the first lens group (LG1) may be the largest, and the composite focal length of the second lens group (LG2) may be the smallest. The relationship between the composite focal lengths of the first to third lens groups (LG1, LG2, LG3) may satisfy |f_LG1| > |f_LG3| > |f_LG2|.

[0193]

[0194] The thickness (CT1) of the first lens (101) may be a difference of at least 1 time between the maximum thickness and the minimum thickness, for example, 1 to 1.5 times, and the center thickness (CT1) may be the maximum and the edge thickness (ET1) may be the minimum. The thickness (T3) of the third lens (103) may be the maximum at the center and the minimum at the edge, and the maximum thickness may be in a range of 2 to 2.5 times the minimum thickness. The thickness (T4) of the fourth lens (104) may be the minimum at the center and the maximum at the edge, and the maximum thickness may be in a range of 1 to 1.5 times the minimum thickness. The thickness (T5) of the fifth lens (105) may be the maximum at the center and the minimum at the edge, and the maximum thickness may be in a range of 1 to 1.5 times the minimum thickness. The thickness (T6) of the sixth lens (106) may be maximum at the center and minimum at the edge, and the maximum thickness is in the range of 1.5 to 2 times the minimum thickness. The thickness (T7) of the seventh lens (107) may be minimum at the center and maximum at the edge, and the maximum thickness is in the range of 1 to 1.5 times the minimum thickness.

[0195]

[0196] The thickness of each lens can satisfy any of the conditions below.

[0197] Condition 1: 1 < CT1 / ET1 < 1.5, 0.5 < ET1 / CT1 < 1

[0198] Condition 2: 2 < CT3 / ET3 < 2.5, 0.1 < ET3 / CT3 < 0.5

[0199] Condition 3: 0.5 < CT4 / ET4 < 1, 1 < ET4 / CT4 < 1.5

[0200] Condition 4: 1 < CT5 / ET5 < 1.5, 0.5 < ET5 / CT5 < 1

[0201] Condition 5: 1.5 < CT6 / ET6 < 2, 0.5 < ET6 / CT6 < 1

[0202] Condition 6: 0.5 < CT7 / ET7 < 1, 1 < ET7 / CT7 < 1.5

[0203] Condition 7: 1 < ΣCT / ΣET < 1.5, 0.5 < ΣET / ΣCT < 1

[0204]

[0205] Among the gaps (G1-G6) between the lenses, the gap (LG1) between the first and second lenses (101, 102) may be maximum in the center and minimum at the edge. The gap (LG2) between the second and third lenses (102, 103) may be minimum in the center and maximum at the edge. The gap (LG3) between the third and fourth lenses (103, 104) may be maximum in the center and minimum at the edge. The gap (G4) between the fourth and fifth lenses (104, 105) may be minimum in the edge and maximum at the center. The fifth gap (G5) between the fifth and sixth lenses (105, 106) may be minimum in the center and maximum at the edge. The sixth gap (G6) between the sixth and seventh lenses (106, 107) may be minimum in the center and maximum at the edge.

[0206]

[0207] Fig. 4 is a graph showing the aberration characteristics of the optical system according to the first embodiment. For example, Fig. 4 may be a graph showing the aberration characteristics in the first mode of the optical system according to the first embodiment. In the aberration graph of Fig. 4, spherical aberration (longitudinal spherical aberration), astigmatic field curves, and distortion are measured from left to right. In Fig. 4, the X-axis may represent a focal length (mm) and a degree of distortion (%), and the Y-axis may represent the height of the image. In addition, the graph for spherical aberration is a graph for light in wavelength bands of about 470 nm, about 501 nm, about 550 nm, about 610 nm, and about 650 nm, and the graphs for astigmatism and distortion are graphs for light in wavelength bands of about 550 nm. In the aberration diagram of Fig. 4, the closer each curve is to the Y-axis, the better the aberration correction function can be interpreted. It can be seen that the optical system (1000) according to the first embodiment has measured values ​​close to the Y-axis in almost all areas. That is, the optical system (1000) according to the first embodiment has improved resolution and can have good optical performance not only in the center of the field of view (FOV) but also in the periphery.

[0208]

[0209] An optical system according to the second embodiment of the invention will be described.

[0210] FIG. 5 is a configuration diagram of an optical system according to the second embodiment of the present invention operating in the first mode, FIG. 6 is a configuration diagram of an optical system according to the second embodiment of the present invention operating in the second mode, FIG. 7 is a table showing aspherical coefficients of lenses in the optical system according to the second embodiment of the present invention, and FIG. 8 is a graph showing data on aberration characteristics of the optical system according to the second embodiment of the present invention operating in the first mode.

[0211] Referring to FIG. 5, the optical system (1100) includes a lens unit, and the lens unit may include first to seventh lenses (201 to 207). The first to seventh lenses (201 to 207) may be sequentially arranged along the optical axis (OA) of the optical system (1100). Light corresponding to information about an object may pass through the first to seventh lenses (201 to 207) and a filter (600) and be incident on the image sensor (500).

[0212] The first lens (201) may be positioned closest to the object side. The first lens (201) may be positioned furthest from the sensor side. The first lens (201) may have positive refractive power. The first lens (201) may include a plastic or glass material. For example, the first lens (201) may be provided as a plastic material.

[0213] The first surface (S1) on the object side of the first lens (201) may be convex with respect to the optical axis, and the second surface (S2) on the sensor side may be concave. The first lens (201) may have a meniscus shape in which the object side is convex. The first lens (201) may have a meniscus shape in which the sensor side is concave. The first lens (201) is made of a plastic material and may have an aspherical surface. The aspherical coefficients of the first surface (S1) and the second surface (S2) of the first lens (201) may be provided as L1S1 and L1S2 of FIG. 7. At least one or both of the first surface (S1) and the second surface (S2) of the first lens (201) may be provided without a critical point from the optical axis to the end of the effective area.

[0214]

[0215] The second lens (202) may be a prism lens. The second lens (202) may be a right-angle prism lens. The second lens (202) may be a light path control member. The second lens (202) may change the path of light incident from the outside. The second lens (202) may include a reflector and a prism. The second lens (202) may rotate the light path by 90 degrees. The second lens (202) includes an incident surface (S3) on which light is incident, a reflective surface (RS1) that reflects the incident light, and an exit surface (S4) that emits the reflected light. The reflective surface (RS1) has an inclination angle of 45 degrees and reflects the principal ray of the incident light at 90 degrees, thereby reflecting the incident light to the third lens (203). The second lens (202) can reflect light incident in the second direction (Y-axis direction) and change the path of the light to the first direction (X-axis direction).

[0216] The aperture (STOP) may be positioned between the second lens (202) and the third lens (203). The aperture may be positioned on the fourth surface (S4) on the sensor side of the second lens (202) or the fifth surface (S5) on the object side of the third lens (203). The aperture can reduce the TTL within the field of view range and enable miniaturization of the optical system. Accordingly, a decrease in the yield by weight of the optical system can be prevented and production efficiency can be improved.

[0217]

[0218] The third lens (203) may be arranged third from the object side. The third lens (203) may be arranged fifth from the sensor side. The third lens (203) may be arranged between the second lens (202) and the fourth lens (204). The third lens (203) may have positive refractive power. The third lens (203) may include a plastic or glass material. For example, the third lens (203) may be provided as a plastic material.

[0219] The fifth surface (S5) on the object side of the third lens (203) with respect to the optical axis may be convex, and the sixth surface (S6) on the sensor side may be concave. The third lens (203) may have a meniscus shape in which the object side is convex. The third lens (203) may have a meniscus shape in which the sensor side is concave. The third lens (203) is made of a plastic material and may have an aspherical surface. The aspherical coefficients of the fifth surface (S5) and the sixth surface (S6) may be provided as L3S1 and L3S2 of FIG. 7. At least one or both of the fifth surface (S5) and the sixth surface (S6) of the third lens (203) may be provided without a critical point from the optical axis to the end of the effective area.

[0220]

[0221] The fourth lens (204) may be arranged fourth from the object side. The fourth lens (204) may be arranged fourth from the sensor side. The fourth lens (204) may be arranged between the third lens (203) and the fifth lens (205). The fourth lens (204) may have negative (-) refractive power. The fourth lens (204) may include a plastic or glass material. For example, the fourth lens (204) may be provided as a plastic material.

[0222] The seventh surface (S7) on the object side of the fourth lens (204) may be convex with respect to the optical axis, and the eighth surface (S8) on the sensor side may be concave. The fourth lens (204) may have a meniscus shape in which the object side is convex. The fourth lens (204) may have a meniscus shape in which the sensor side is concave. The fourth lens (204) is made of a plastic material and may have an aspherical surface. The aspherical coefficients of the seventh surface (S7) and the eighth surface (S8) may be provided as L4S1 and L4S2 of FIG. 7. At least one or both of the seventh surface (S7) and the eighth surface (S8) of the fourth lens (204) may be provided without a critical point from the optical axis to the end of the effective area.

[0223]

[0224] The fifth lens (205) may be arranged as the fifth lens from the object side. The fifth lens (205) may be arranged as the third lens from the sensor side. The fifth lens (205) may be arranged between the fourth lens (204) and the sixth lens (206). The fifth lens (205) may have positive (+) refractive power. The fifth lens (205) may include a plastic or glass material. For example, the fifth lens (205) may be provided as a plastic material.

[0225] With respect to the optical axis (OA), the ninth surface (S9) on the object side of the fifth lens (205) may be convex, and the tenth surface (S10) on the sensor side may be convex. The fifth lens (205) may have a shape in which both sides are convex. The fifth lens (205) may be made of a plastic material and may have an aspherical surface. The aspherical coefficients of the ninth surface (S9) and the tenth surface (S10) may be provided as L5S1 and L5S2 of FIG. 7.

[0226] The ninth surface (S9) of the fifth lens (205) may have a critical point from the optical axis to the end of the effective area. When the ninth surface (S9) has a critical point, it may be located in a range of 50% to 70%, preferably 60% to 65%, of the effective radius from the optical axis. The critical point of the ninth surface (S9) may be located in a range of 1.3 mm to 2.5 mm, preferably 1.5 mm to 2.0 mm from the optical axis. The critical point of the ninth surface (S9) may be a point where the sign of the gradient value with respect to the optical axis and the direction perpendicular to the optical axis changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the gradient value is 0. In addition, the critical point of the ninth surface (S9) may be a point where the gradient value of a tangent passing through the lens surface increases and then decreases, or a point where the gradient value decreases and then increases. The tenth surface (S10) of the fifth lens (205) can be provided without a critical point from the optical axis to the end of the effective area.

[0227]

[0228] The sixth lens (206) may be arranged as the sixth lens from the object side. The sixth lens (206) may be arranged as the second lens from the sensor side. The sixth lens (206) may be arranged between the fifth lens (205) and the seventh lens (207). The sixth lens (206) may have positive (+) refractive power. The sixth lens (206) may include a plastic or glass material. For example, the sixth lens (206) may be provided as a plastic material.

[0229] With respect to the optical axis (OA), the eleventh surface (S11) on the object side of the sixth lens (206) may be concave, and the twelfth surface (S12) on the sensor side may be convex. The sixth lens (206) may have a meniscus shape in which the object side is concave. The sixth lens (206) may have a meniscus shape in which the sensor side is convex. The sixth lens (206) is made of a plastic material and may have an aspherical surface. The aspherical coefficients of the eleventh surface (S11) and the twelfth surface (S12) may be provided as L6S1 and L6S2 of FIG. 7. At least one or both of the eleventh surface (S11) and the twelfth surface (S12) of the sixth lens (206) may be provided without a critical point from the optical axis to the end of the effective area.

[0230]

[0231] The seventh lens (207) may be arranged closest to the sensor side. The seventh lens (207) may be arranged farthest from the object side. The seventh lens (207) may be arranged between the sixth lens (206) and the filter (600). The seventh lens (207) may be arranged between the sixth lens (206) and the image sensor (500). The seventh lens (207) may have negative (-) refractive power. The seventh lens (207) may include a plastic or glass material. For example, the seventh lens (207) may be provided with a plastic material.

[0232] With respect to the optical axis (OA), the 13th surface (S13) on the object side of the seventh lens (207) may be concave, and the 14th surface (S14) on the sensor side may be concave. The seventh lens (207) may have a concave shape on both sides. The seventh lens (207) may be made of a plastic material and may have an aspherical surface. The aspherical coefficients of the 13th surface (S13) and the 14th surface (S14) may be provided as L7S1 and L7S2 of FIG. 7.

[0233] The 13th surface (S13) of the seventh lens (207) may be provided without a critical point from the optical axis to the end of the effective area. The 14th surface (S14) of the seventh lens (207) may have a critical point from the optical axis to the end of the effective area. When the 14th surface (S14) has a critical point, it may be located in a range of 60% to 80%, preferably in a range of 65% to 75%, of the effective radius from the optical axis. The critical point of the 14th surface (S14) may be located in a range of 1.5 mm to 3.0 mm, preferably in a range of 2.0 mm to 2.5 mm from the optical axis. The critical point of the 14th surface (S14) is a point where the sign of the gradient value with respect to the optical axis and the direction perpendicular to the optical axis changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the gradient value is 0. Additionally, the critical point of the 14th surface (S14) may be a point where the slope value of the tangent line passing through the lens surface increases and then decreases, or a point where the slope value decreases and then increases.

[0234]

[0235] LensSurfaceRadiusThicknessndvdClearAperture1S17.9601.3601.55056.0007.800 S212.0001.140 7.2902S3Infinity6.6001.72029.5007.190STOPS4Infinity1.200 6.2703S55.1700.9501.55056.0005.770 S618.1700.130 5.6404S77.1800.9501.68019.2005.550 S83.1402.250 5.0205S9113.4902.6501.68019.2005.440S10-7.230Variable (D1) 5.8806S11-4.8001.5001.55056.0005.800 S12-4.1400.250 5.9307S13-21.9002.3001.68019.2005.640 S1411.580Variable (D2) 6.530Filter Infinity Infinity Image Infinity

[0236] Table 4 shows the surface number (Surface), radius of curvature (Radius), center thickness of each lens or distance between lens surfaces (Thickness), refractive index (Index,nd), Abbe number (Abbe,vd), clear aperture, and focal length of the lens according to the second embodiment of the present invention. At this time, the unit of the radius of curvature and thickness or distance may be mm.

[0237] In Table 4, the thickness of the second lens (202), which is a prism lens, may refer to the thickness along the optical axis (OA). For example, the thickness of the second lens (202) may refer to the sum of the thickness from the object side (S3) to the reflective surface (RS1) on the y-axis and the thickness from the reflective surface (RS1) to the sensor side (S4) on the x-axis. In addition, the thickness of the second lens (202) from the object side (S3) to the reflective surface (RS1) on the y-axis and the thickness of the second lens (202) from the reflective surface (RS1) to the sensor side (S4) on the x-axis may be the same. According to a variation, the thickness of the second lens (202) from the object side (S3) to the reflective surface (RS1) on the y-axis and the thickness of the second lens (202) from the reflective surface (RS1) to the sensor side (S4) on the x-axis may be different.

[0238]

[0239] Mode 1 Mode 2 D11.3201.740 D26.3705.950

[0240] Table 5 shows the distances (D1, D2) between lenses that are variable when the optical system according to the second embodiment of the present invention operates in one of the first and second modes. Here, the first mode may refer to a case where an object located at infinity is photographed, and the second mode may refer to a case where an object located at a close range (macroscopic) (e.g., within 1000 mm) is photographed.

[0241] In the optical system according to the second embodiment of the present invention, the distance between adjacent lens groups may change during the process of changing the magnification from the first mode to the second mode. The first and second lens groups (LG1, LG2) may be fixed, and the third lens group (LG3) may be movable. The first and second lens groups (LG1, LG2) may be fixed groups, and the third lens group (LG3) may be a movable group.

[0242] When operating from the first mode to the second mode, the distance (D1) between the second lens group (LG2) and the third lens group (LG3) may increase, and the distance (D2) between the third lens group (LG3) and the image sensor (500) may decrease.

[0243] When operating from the second mode to the first mode, the distance (D1) between the second lens group (LG2) and the third lens group (LG3) may decrease, and the distance (D2) between the third lens group (LG3) and the image sensor (500) may increase.

[0244] The stroke length of the third lens group (LG3) can satisfy 0.3 mm to 0.5 mm, and preferably, can satisfy about 0.420 mm.

[0245]

[0246] EFL(F)20.750EPD7.800BFL_16.370SD12.300BFL_25.950TD22.600FOV_121.900TD_LG19.100FOV_221.900TD_LG26.930 f138.750TD_LG34.050f2-f_LG138.750f312.920f_LG213.740f4-9.060f_LG3-15.100f510.100LG3_stroke0.420f630.6 60TTL28.970f7-10.860ImgH8.200ET10.880ΣCT16.310ET26.600ΣCG6.290ET30.340CA_Max7.545ET41.500CA_Min5.285 ET51.980CA_Aver6.125ET61.140L_CT_max6.600ET72.920L_CT_min0.950Fno2.700L_CT_aver2.330TL_Y5.80TL_X23.17

[0247] Table 6 shows the items of the mathematical formulas described above in the optical system (1100) of the present embodiment, including the effective focal length (EFL (F) (mm)) in the first mode of the optical system (1100), the distance from the sensor side of the last lens to the image sensor (BFL_1 (mm)) in the first mode, the distance from the sensor side of the last lens to the image sensor (BFL_2 (mm)) in the second mode, the angle of view (FOV_1 (degree)) in the first mode, the angle of view (FOV_2 (degree)) in the second mode, the focal lengths (f1 to f7) (mm) of the first to seventh lenses (201 to 207), the edge thickness (ET1 to ET7), the lengths of each lens group in the optical axis direction (TD_LG1, TD_LG2, TD_LG3), the focal lengths (f_LG1, f_LG2, f_LG3) (mm) of the first to third lens groups (LG1, LG2, LG3), The size of the entrance pupil (EPD (mm)), the optical axis distance (SD (mm)) from the aperture (STOP) to the fourteenth surface (S14), the optical axis distance (TD (mm)) from the first lens (201) to the seventh lens (207), the brightness (Fno) of the optical system (1100), the stroke length (LG3_stroke) of the third lens group (LG3), the total optical axis distance of the optical system (1100) TTL (mm), ImgH (mm), the maximum effective diameter (CA_Max), the minimum effective diameter (CA_Min), the average effective diameter (CA_Aver), the maximum center thickness (L_CT_max), the minimum center thickness (L_CT_min), the average center thickness (L_CT_aver) among the first to seventh lenses (201 to 207), the length in the Y-axis direction (TL_Y) of the optical system (1100), and the length in the X-axis direction (TL_X) of the optical system (1100).

[0248]

[0249] Hereinafter, the center thicknesses of the first to seventh lenses (201 to 207) are represented by CT1 to CT7, the edge thicknesses at the ends of the effective areas of each lens are represented by ET1 to ET7, and the center gap between two adjacent lenses is represented by CG1 to CG6. The back focal length (BFL) is the optical axis distance from the image sensor (500) to the center of the last lens. The TTL is the optical axis distance from the center of the first surface (S1) of the first lens (201) to the upper surface of the image sensor (500).

[0250]

[0251] When comparing the absolute values ​​of the curvature radii of each lens, the curvature radii of the ninth surface (S9) of the fifth lens (205) on the optical axis (OA) may be the largest among the lenses, and the curvature radii of the eighth surface (S8) of the fourth lens (204) may be the smallest among the lenses. The absolute value of the curvature radii of the first surface (S1) of the first lens (201) may be smaller than the absolute value of the curvature radii of the second surface (S2). The absolute value of the curvature radii of the fifth surface (S5) of the third lens (203) may be smaller than the absolute value of the curvature radii of the sixth surface (S6). The absolute value of the curvature radii of the seventh surface (S7) of the fourth lens (204) may be larger than the absolute value of the curvature radii of the eighth surface (S8). The absolute value of the curvature radius of the ninth surface (S9) of the fifth lens (205) may be greater than the absolute value of the curvature radius of the tenth surface (S10). The absolute value of the curvature radius of the eleventh surface (S11) of the sixth lens (206) may be greater than the absolute value of the curvature radius of the twelfth surface (S12). The absolute value of the curvature radius of the thirteenth surface (S13) of the seventh lens (207) may be greater than the absolute value of the curvature radius of the fourteenth surface (S14).

[0252]

[0253] Condition 1: 0.5 < |L1R1 / L1R2| < 1

[0254] Condition 2: 0.1 < |L3R1 / L3R2| < 0.5

[0255] Condition 3: 2 < |L4R1 / L4R2| < 2.5

[0256] Condition 4: 10 < |L5R1 / L5R2| < 20

[0257] Condition 5: 1 < |L6R1 / L6R2| < 1.5

[0258] Condition 6: 1.5 < |L7R1 / L7R2| < 2

[0259]

[0260] When describing the central thickness of the lenses based on the optical axis, the central thickness (CT2) of the second lens (202) is the largest among the lenses, and the central thicknesses (CT3, CT4) of the third lens (203) and the fourth lens (204) are the smallest among the lenses. The difference between the maximum central thickness and the minimum central thickness among the lenses may be in the range of 5 mm or more and 6 mm or less.

[0261] The central thickness of each lens may satisfy any one of the following conditions:

[0262] Condition 1: CT2, CT5, CT6, CT7 > CT1 > CT3, CT4

[0263] Condition 2: CT2 > CT1, CT3, CT4, CT5, CT6, CT7

[0264] Condition 3: CT1, CT2, CT5, CT6, CT7 > CT3 = CT4

[0265] Condition 4: CT2 > CT5 > CT1, CT3, CT4, CT6, CT7

[0266] Condition 5: CT2, CT5, CT7 > CT6 > CT1, CT3, CT4

[0267] Condition 6: CT2, CT5 > CT7 > CT1, CT3, CT4, CT6

[0268]

[0269] When zooming, the distance (CG1) between the first lens (201) and the second lens (202), the distance (CG2) between the second lens (202) and the third lens (203), the distance (CG3) between the third lens (203) and the fourth lens (204), the distance (CG4) between the fourth lens (204) and the fifth lens (205), and the distance (CG6) between the sixth lens (206) and the seventh lens (207) do not change, while the distance (CG5) between the fifth lens (205) and the sixth lens (206) can change. Among the center distances between the lenses that do not change, the distance (CG4) between the fourth lens (204) and the fifth lens (205) can be the maximum, and the distance (CG3) between the third lens (203) and the fourth lens (204) can be the minimum. The difference between the maximum center spacing and the minimum center spacing among the lens spacings may be 2.0 mm or more, for example, in the range of 2.0 mm to 2.5 mm.

[0270] The center spacing between each lens can satisfy the conditions below.

[0271] Condition 1: CG2, CG4 > CG1 > CG3, CG6

[0272] Condition 2: CG4 > CG2 > CG1, CG3, CG6

[0273] Condition 3: CG1, CG2, CG4, CG6 > CG3

[0274] Condition 4: CG4 > CG1, CG2, CG3, CG6

[0275] Condition 5: CG1, CG2, CG4 > CG6 > CG3

[0276]

[0277] Regarding the effective diameter, the lens having the maximum effective diameter may be the first lens (201). Here, the effective diameter is the average of the effective diameters of the object-side surface and the sensor-side surface of each lens. The lens surface having the maximum effective diameter may be the first surface (S1) of the first lens (201). The lens having the minimum effective diameter may be the fourth lens (204). The lens surface having the minimum effective diameter may be the eighth surface (S8) of the fourth lens (204). The effective diameters of the first to seventh lenses (201-207) may be smaller than the diagonal length of the image sensor (500).

[0278] The effective diameter of each lens can satisfy any one of the conditions below.

[0279] Condition 1: CA_L1 > CA_L2, CA_L3, CA_L4, CA_L5, CA_L6, CA_L7

[0280] Condition 2: CA_L1 > CA_L2 > CA_L3, CA_L4, CA_L5, CA_L6, CA_L7

[0281] Condition 3: CA_L1, CA_L2, CA_L6, CA_L7 > CA_L3 > CA_L4, CA_L5

[0282] Condition 4: CA_L1, CA_L2, CA_L3, CA_L5, CA_L6, CA_L7 > CA_L4

[0283] Condition 5: CA_L1, CA_L2, CA_L3, CA_L6, CA_L7 > CA_L5 > CA_L4

[0284] Condition 6: CA_L1, CA_L2, CA_L7 > CA_L6 > CA_L3, CA_L4, CA_L5

[0285] Condition 7: CA_L1, CA_L2 > CA_L7 > CA_L3, CA_L4, CA_L5, CA_L6

[0286]

[0287] Regarding the refractive index, the refractive index of the second lens (202) may be the highest among the lenses and may be greater than 1.6, for example, greater than 1.7. Any one of the first lens (201), the third lens (203), and the sixth lens (206) may have the lowest refractive index among the lenses. For example, the refractive index of any one of the first lens (201), the third lens (203), and the sixth lens (206) may be the lowest among the lenses and may be less than 1.6, for example, less than 1.57. The difference between the maximum refractive index and the minimum refractive index may be 0.1 or more.

[0288] The refractive index of each lens can satisfy any of the conditions below.

[0289] Condition 1: n2, n4, n5, n7 > n1 = n3 = n6

[0290] Condition 2: n2 > n1, n3, n4, n5, n6, n7

[0291] Condition 3: n2 > n4 = n5 = n7 > n1, n3, n6

[0292]

[0293] Comparing the Abbe numbers, the Abbe numbers of the first lens (201), the third lens (203), and the sixth lens (206) are the largest among the lenses and may be 50 or more. The Abbe numbers of the fourth lens (204), the fifth lens (205), and the seventh lens (207) are the smallest among the lenses and may be 20 or less. The difference between the maximum refractive index and the minimum Abbe number may be 30 or more.

[0294] The Abbe number of each lens can satisfy any of the conditions below.

[0295] Condition 1: v1 = v3 = v6 > v2, v4, v5, v7

[0296] Condition 2: v1, v3, v6 > v2 > v4, v5, v7

[0297] Condition 3: v1, v2, v3, v6 > v4 = v5 = v7

[0298]

[0299] The focal lengths (F1, F3, F5, F6) of the first, third, fifth, and sixth lenses (201, 203, 205, and 206) may have a positive (+) sign. The first, third, fifth, and sixth lenses (201, 203, 205, and 206) may have a positive (+) refractive power. The focal lengths (F4, F7) of the fourth and seventh lenses (204, 207) may have a negative (-) sign. The fourth and seventh lenses (204, 207) may have a negative (-) refractive power. When comparing the focal lengths in absolute values, the focal length of the first lens (201) is the largest among the lenses and may be 30 or more and 50 or less. The focal length of the fourth lens (204) is the smallest among the lenses, and the absolute value of the focal length of the fourth lens (204) may be 5 or more and 10 or less.

[0300] The absolute value of the focal length of each lens can satisfy any of the conditions below.

[0301] Condition 1: |f1| > |f3|, |f4|, |f5|, |f6|, |f7|

[0302] Condition 2: |f1|, |f6| > |f3| > |f4|, |f5|, |f7|

[0303] Condition 3: |f1|, |f3|, |f5|, |f6|, |f7| > |f4|

[0304] Condition 4: |f1|, |f3|, |f6|, |f7| > |f5| > |f4|

[0305] Condition 5: |f1| > |f6| > |f3|, |f4|, |f5|, |f7|

[0306] Condition 6: |f1|, |f3|, |f6| > |f7| > |f4|, |f5|

[0307]

[0308] The composite focal length (f_LG1) of the first lens group (LG1) can have a positive (+) sign. The first lens group (LG1) can have a positive (+) composite refractive power. The composite focal length (f_LG2) of the second lens group (LG2) can have a positive (+) sign. The second lens group (LG2) can have a positive (+) composite refractive power. The composite focal length (f_LG3) of the third lens group (LG3) can have a negative (-) sign. The third lens group (LG3) can have a negative (-) composite refractive power. Through this, light incident from the object side can move away from the optical axis direction and then gather again in the optical axis direction, thereby forming a stable optical path.

[0309] When comparing the absolute values ​​of the composite focal lengths of the first to third lens groups (LG1, LG2, LG3), the composite focal length of the first lens group (LG1) may be the largest, and the composite focal length of the second lens group (LG2) may be the smallest. The relationship between the composite focal lengths of the first to third lens groups (LG1, LG2, LG3) may satisfy |f_LG1| > |f_LG3| > |f_LG2|.

[0310]

[0311] The thickness (CT1) of the first lens (201) may be a difference of at least 1 time between the maximum thickness and the minimum thickness, for example, 1 to 1.5 times, and the center thickness (CT1) may be the maximum and the edge thickness (ET1) may be the minimum. The thickness (T3) of the third lens (203) may be the maximum at the center and the minimum at the edge, and the maximum thickness may be in a range of 2 to 2.5 times the minimum thickness. The thickness (T4) of the fourth lens (204) may be the minimum at the center and the maximum at the edge, and the maximum thickness may be in a range of 1 to 1.5 times the minimum thickness. The thickness (T5) of the fifth lens (205) may be the maximum at the center and the minimum at the edge, and the maximum thickness may be in a range of 1 to 1.5 times the minimum thickness. The thickness (T6) of the sixth lens (206) may be maximum at the center and minimum at the edge, and the maximum thickness is in the range of 1.5 to 2 times the minimum thickness. The thickness (T7) of the seventh lens (207) may be minimum at the center and maximum at the edge, and the maximum thickness is in the range of 1 to 1.5 times the minimum thickness.

[0312]

[0313] The thickness of each lens can satisfy any of the conditions below.

[0314] Condition 1: 1 < CT1 / ET1 < 1.5, 0.5 < ET1 / CT1 < 1

[0315] Condition 2: 2 < CT3 / ET3 < 2.5, 0.1 < ET3 / CT3 < 0.5

[0316] Condition 3: 0.5 < CT4 / ET4 < 1, 1 < ET4 / CT4 < 1.5

[0317] Condition 4: 1 < CT5 / ET5 < 1.5, 0.5 < ET5 / CT5 < 1

[0318] Condition 5: 1.5 < CT6 / ET6 < 2, 0.5 < ET6 / CT6 < 1

[0319] Condition 6: 0.5 < CT7 / ET7 < 1, 1 < ET7 / CT7 < 1.5

[0320] Condition 7: 1 < ΣCT / ΣET < 1.5, 0.5 < ΣET / ΣCT < 1

[0321]

[0322] Among the gaps (G1-G6) between the lenses, the gap (LG1) between the first and second lenses (201, 202) may have a maximum in the center and a minimum at the edge. The gap (LG2) between the second and third lenses (202, 203) may have a minimum in the center and a maximum at the edge. The gap (LG3) between the third and fourth lenses (203, 204) may have a maximum in the center and a minimum at the edge. The gap (G4) between the fourth and fifth lenses (204, 205) may have a minimum in the edge and a maximum at the center. The fifth gap (G5) between the fifth and sixth lenses (205, 206) may have a minimum in the center and a maximum at the edge. The sixth gap (G6) between the sixth and seventh lenses (206, 207) may have a minimum in the center and a maximum at the edge.

[0323]

[0324] Fig. 8 is a graph showing the aberration characteristics of the optical system according to the second embodiment. For example, Fig. 8 may be a graph showing the aberration characteristics in the first mode of the optical system according to the second embodiment. In the aberration graph of Fig. 8, spherical aberration (longitudinal spherical aberration), astigmatic field curves, and distortion are measured from left to right. In Fig. 8, the X-axis may represent the focal length (mm) and the degree of distortion (%), and the Y-axis may represent the height of the image. In addition, the graph for spherical aberration is a graph for light in wavelength bands of about 470 nm, about 501 nm, about 550 nm, about 610 nm, and about 650 nm, and the graphs for astigmatism and distortion are graphs for light in wavelength bands of about 550 nm. In the aberration diagram of Fig. 8, the closer each curve is to the Y-axis, the better the aberration correction function can be interpreted. It can be seen that the optical system (1100) according to the second embodiment has measured values ​​close to the Y-axis in almost all areas. That is, the optical system (1100) according to the second embodiment has improved resolution and can have good optical performance not only in the center of the field of view (FOV) but also in the periphery.

[0325]

[0326] An optical system according to the third embodiment of the invention will be described.

[0327] FIG. 9 is a configuration diagram of an optical system according to the third embodiment of the present invention operating in the first mode, FIG. 10 is a configuration diagram of an optical system according to the third embodiment of the present invention operating in the second mode, FIG. 11 is a table showing aspherical coefficients of lenses in the optical system according to the third embodiment of the present invention, and FIG. 12 is a graph showing data on aberration characteristics of the optical system according to the third embodiment of the present invention operating in the first mode.

[0328] Referring to FIG. 9, the optical system (1200) includes a lens unit, and the lens unit may include first to seventh lenses (301 to 307). The first to seventh lenses (301 to 307) may be sequentially arranged along the optical axis (OA) of the optical system (1200). Light corresponding to information about an object may pass through the first to seventh lenses (301 to 307) and the filter (600) and be incident on the image sensor (500).

[0329] The first lens (301) may be positioned closest to the object side. The first lens (301) may be positioned furthest from the sensor side. The first lens (301) may have positive refractive power. The first lens (301) may include a plastic or glass material. For example, the first lens (301) may be provided as a plastic material.

[0330] The first surface (S1) on the object side of the first lens (301) may be convex with respect to the optical axis, and the second surface (S2) on the sensor side may be concave. The first lens (301) may have a meniscus shape in which the object side is convex. The first lens (301) may have a meniscus shape in which the sensor side is concave. The first lens (301) is made of a plastic material and may have an aspherical surface. The aspherical coefficients of the first surface (S1) and the second surface (S2) of the first lens (301) may be provided as L1S1 and L1S2 of FIG. 11. At least one or both of the first surface (S1) and the second surface (S2) of the first lens (301) may be provided without a critical point from the optical axis to the end of the effective area.

[0331]

[0332] The second lens (302) may be a prism lens. The second lens (302) may be a right-angle prism lens. The second lens (302) may be a light path control member. The second lens (302) can change the path of light incident from the outside. The second lens (302) may include a reflector and a prism. The second lens (302) can rotate the light path by 90 degrees. The second lens (302) includes an incident surface (S3) on which light is incident, a reflective surface (RS1) that reflects the incident light, and an exit surface (S4) that emits the reflected light. The reflective surface (RS1) has an inclination angle of 45 degrees and reflects the principal ray of the incident light at 90 degrees, thereby reflecting the incident light to the third lens (303). The second lens (302) can reflect light incident in the second direction (Y-axis direction) and change the path of the light to the first direction (X-axis direction).

[0333] The aperture (STOP) may be positioned between the second lens (302) and the third lens (303). The aperture may be positioned on the sensor-side fourth surface (S4) of the second lens (302) or the object-side fifth surface (S5) of the third lens (303). The aperture can reduce the TTL within the field of view range and enable miniaturization of the optical system. Accordingly, a decrease in the yield by weight of the optical system can be prevented and production efficiency can be improved.

[0334]

[0335] The third lens (303) may be arranged third from the object side. The third lens (303) may be arranged fifth from the sensor side. The third lens (303) may be arranged between the second lens (302) and the fourth lens (304). The third lens (303) may have positive refractive power. The third lens (303) may include a plastic or glass material. For example, the third lens (303) may be provided with a plastic material. The fifth surface (S5) on the object side of the third lens (303) with respect to the optical axis may be convex, and the sixth surface (S6) on the sensor side may include a flat surface. The third lens (303) may be made of a plastic material and may have an aspherical surface. The aspherical coefficients of the fifth surface (S5) and the sixth surface (S6) may be provided as L3S1 and L3S2 of FIG. 11.

[0336] The fifth surface (S5) of the third lens (303) may be provided without a critical point from the optical axis to the end of the effective area. The sixth surface (S6) of the third lens (303) may have a critical point from the optical axis to the end of the effective area. When the sixth surface (S6) has a critical point, it may be located in a range of 30% to 50%, preferably in a range of 40% to 45%, of the effective radius from the optical axis. The critical point of the sixth surface (S6) may be located in a range of 0.5 mm to 2.0 mm, preferably in a range of 1.0 mm to 1.5 mm from the optical axis. The critical point of the sixth surface (S6) may be a point where the sign of the gradient value with respect to the optical axis and the direction perpendicular to the optical axis changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the gradient value is 0. Additionally, the critical point of the sixth surface (S6) may be a point where the slope value of the tangent line passing through the lens surface increases and then decreases, or a point where the slope value decreases and then increases.

[0337]

[0338] The fourth lens (304) may be arranged fourth from the object side. The fourth lens (304) may be arranged fourth from the sensor side. The fourth lens (304) may be arranged between the third lens (303) and the fifth lens (305). The fourth lens (304) may have negative (-) refractive power. The fourth lens (304) may include a plastic or glass material. For example, the fourth lens (304) may be provided as a plastic material.

[0339] The seventh surface (S7) on the object side of the fourth lens (304) with respect to the optical axis may be convex, and the eighth surface (S8) on the sensor side may be concave. The fourth lens (304) may have a meniscus shape in which the object side is convex. The fourth lens (304) may have a meniscus shape in which the sensor side is concave. The fourth lens (304) is made of a plastic material and may have an aspherical surface. The aspherical coefficients of the seventh surface (S7) and the eighth surface (S8) may be provided as L4S1 and L4S2 of FIG. 11. At least one or both of the seventh surface (S7) and the eighth surface (S8) of the fourth lens (304) may be provided without a critical point from the optical axis to the end of the effective area.

[0340]

[0341] The fifth lens (305) may be arranged as the fifth lens from the object side. The fifth lens (305) may be arranged as the third lens from the sensor side. The fifth lens (305) may be arranged between the fourth lens (304) and the sixth lens (306). The fifth lens (305) may have positive (+) refractive power. The fifth lens (305) may include a plastic or glass material. For example, the fifth lens (305) may be provided as a plastic material.

[0342] With respect to the optical axis (OA), the ninth surface (S9) on the object side of the fifth lens (305) may be convex, and the tenth surface (S10) on the sensor side may be convex. The fifth lens (305) may have a shape in which both sides are convex. The fifth lens (305) may be made of a plastic material and may have an aspherical surface. The aspherical coefficients of the ninth surface (S9) and the tenth surface (S10) may be provided as L5S1 and L5S2 of FIG. 11. At least one or both of the ninth surface (S9) and the tenth surface (S10) of the fifth lens (305) may be provided without a critical point from the optical axis to the end of the effective area.

[0343]

[0344] The sixth lens (306) may be arranged as the sixth lens from the object side. The sixth lens (306) may be arranged as the second lens from the sensor side. The sixth lens (306) may be arranged between the fifth lens (305) and the seventh lens (307). The sixth lens (306) may have positive (+) refractive power. The sixth lens (306) may include a plastic or glass material. For example, the sixth lens (306) may be provided as a plastic material.

[0345] With respect to the optical axis (OA), the eleventh surface (S11) on the object side of the sixth lens (306) may be concave, and the twelfth surface (S12) on the sensor side may be convex. The sixth lens (306) may have a meniscus shape in which the object side is concave. The sixth lens (306) may have a meniscus shape in which the sensor side is convex. The sixth lens (306) is made of a plastic material and may have an aspherical surface. The aspherical coefficients of the eleventh surface (S11) and the twelfth surface (S12) may be provided as L6S1 and L6S2 of FIG. 11. At least one or both of the eleventh surface (S11) and the twelfth surface (S12) of the sixth lens (306) may be provided without a critical point from the optical axis to the end of the effective area.

[0346]

[0347] The seventh lens (307) may be arranged closest to the sensor side. The seventh lens (307) may be arranged farthest from the object side. The seventh lens (307) may be arranged between the sixth lens (306) and the filter (600). The seventh lens (307) may be arranged between the sixth lens (306) and the image sensor (500). The seventh lens (307) may have negative (-) refractive power. The seventh lens (307) may include a plastic or glass material. For example, the seventh lens (307) may be provided with a plastic material.

[0348] With respect to the optical axis (OA), the 13th surface (S13) on the object side of the seventh lens (307) may be convex, and the 14th surface (S14) on the sensor side may be concave. The seventh lens (307) may have a meniscus shape in which the object side is convex. The seventh lens (307) may have a meniscus shape in which the sensor side is concave. The seventh lens (307) is made of a plastic material and may have an aspherical surface. The aspherical coefficients of the 13th surface (S13) and the 14th surface (S14) may be provided as L7S1 and L7S2 of FIG. 11.

[0349] The thirteenth surface (S13) of the seventh lens (307) may have a critical point from the optical axis to the end of the effective area. When the thirteenth surface (S13) has a critical point, it may be located in a range of 50% to 70%, preferably 60% to 65%, of the effective radius from the optical axis. The critical point of the thirteenth surface (S13) may be located in a range of 1.5 mm to 3.0 mm, preferably 2.0 mm to 2.5 mm from the optical axis. The critical point of the thirteenth surface (S13) may be a point where the sign of the gradient value with respect to the optical axis and the direction perpendicular to the optical axis changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the gradient value is 0. In addition, the critical point of the thirteenth surface (S13) may be a point where the gradient value of a tangent passing through the lens surface increases and then decreases, or a point where the gradient value decreases and then increases.

[0350] The fourteenth surface (S14) of the seventh lens (307) may have a critical point from the optical axis to the end of the effective area. When the fourteenth surface (S14) has a critical point, it may be located in a range of 85% to 99%, preferably 90% to 95%, of the effective radius from the optical axis. The critical point of the fourteenth surface (S14) may be located in a range of 2.5 mm to 4.0 mm, preferably 3.0 mm to 3.5 mm from the optical axis. The critical point of the fourteenth surface (S14) may be a point where the sign of the gradient value with respect to the optical axis and the direction perpendicular to the optical axis changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the gradient value is 0. In addition, the critical point of the fourteenth surface (S14) may be a point where the gradient value of a tangent passing through the lens surface increases and then decreases, or a point where the gradient value decreases and then increases.

[0351]

[0352] LensSurfaceRadiusThicknessndvdClearAperture1S18.9701.5001.55056.0007.800 S210.1101.270 7.2902S3Infinity6.8001.72029.5007.250STOPS4Infinity0.800 6.9403S56.4302.5001.55056.0006.810 S6Infinity0.200 6.4604S721.9502.8001.68019.2006.300 S84.6601.630 5.1505S921.0001.5501.68019.2005.770S10-23.290Variable(D1) 5.8106S11-7.1201.5001.55056.0005.880 S12-7.4200.300 6.2307S1330.5202.3001.68019.2006.340 S1412.170Variable(D2) 6.940Filter Infinity Infinity Image Infinity

[0353] Table 7 shows the surface number (Surface), radius of curvature (Radius), center thickness of each lens or distance between lens surfaces (Thickness), refractive index (Index,nd), Abbe number (Abbe,vd), clear aperture, and focal length of the lens according to the third embodiment of the present invention. At this time, the unit of the radius of curvature and thickness or distance may be mm.

[0354] In Table 7, the thickness of the second lens (302), which is a prism lens, may refer to the thickness along the optical axis (OA). For example, the thickness of the second lens (302) may refer to the sum of the thickness from the object side (S3) to the reflective surface (RS1) on the y-axis and the thickness from the reflective surface (RS1) to the sensor side (S4) on the x-axis. In addition, the thickness of the second lens (302) from the object side (S3) to the reflective surface (RS1) on the y-axis and the thickness of the second lens (302) from the reflective surface (RS1) to the sensor side (S4) on the x-axis may be the same. According to a variation, the thickness of the second lens (302) from the object side (S3) to the reflective surface (RS1) on the y-axis and the thickness of the second lens (302) from the reflective surface (RS1) to the sensor side (S4) on the x-axis may be different.

[0355]

[0356] Mode 1 Mode 2 D11.8503.330 D24.7803.300

[0357] Table 8 shows the distances (D1, D2) between lenses that are variable when the optical system according to the third embodiment of the present invention operates in one of the first and second modes. Here, the first mode may refer to a case where an object located at infinity is photographed, and the second mode may refer to a case where an object located at a close range (macroscopic) (e.g., within 1000 mm) is photographed.

[0358] In the optical system according to the third embodiment of the present invention, the distance between adjacent lens groups may change during the process of changing the magnification from the first mode to the second mode. The first and second lens groups (LG1, LG2) may be fixed, and the third lens group (LG3) may be movable. The first and second lens groups (LG1, LG2) may be fixed groups, and the third lens group (LG3) may be a movable group.

[0359] When operating from the first mode to the second mode, the distance (D1) between the second lens group (LG2) and the third lens group (LG3) may increase, and the distance (D2) between the third lens group (LG3) and the image sensor (500) may decrease.

[0360] When operating from the second mode to the first mode, the distance (D1) between the second lens group (LG2) and the third lens group (LG3) may decrease, and the distance (D2) between the third lens group (LG3) and the image sensor (500) may increase.

[0361] The stroke length of the third lens group (LG3) can satisfy 1.0 mm to 1.5 mm, and preferably, can satisfy about 1.480 mm.

[0362]

[0363] EFL(F)20.760EPD7.800BFL_14.780SD14.630BFL_23.300TD24.990FOV_121.900TD_LG19.570FOV_222.000TD_LG28.680 f199.820TD_LG34.100f2-f_LG199.820f311.790f_LG218.870f4-9.330f_LG3-31.630f516.500LG3_stroke1.480f6420. 650TTL29.770f7-31.410ImgH8.200ET11.300ΣCT18.950ET26.800ΣCG6.050ET31.540CA_Max7.545ET43.410CA_Min5.725 ET51.090CA_Aver6.498ET61.480L_CT_max6.800ET72.520L_CT_min1.500Fno2.700L_CT_aver2.707TL_Y6.17TL_X23.61

[0364] Table 9 shows the items of the mathematical formulas described above in the optical system (1200) of the present embodiment, including the effective focal length (EFL (F) (mm)) in the first mode of the optical system (1200), the distance from the sensor side of the last lens to the image sensor (BFL_1 (mm)) in the first mode, the distance from the sensor side of the last lens to the image sensor (BFL_2 (mm)) in the second mode, the angle of view (FOV_1 (degree)) in the first mode, the angle of view (FOV_2 (degree)) in the second mode, the focal lengths (f1 to f7) (mm) of the first to seventh lenses (301 to 307), the edge thickness (ET1 to ET7), the lengths of each lens group in the optical axis direction (TD_LG1, TD_LG2, TD_LG3), the focal lengths (f_LG1, f_LG2, f_LG3) (mm) of the first to third lens groups (LG1, LG2, LG3), The size of the entrance pupil (EPD (mm)), the optical axis distance (SD (mm)) from the aperture (STOP) to the fourteenth surface (S14), the optical axis distance (TD (mm)) from the first lens (301) to the seventh lens (307), the brightness (Fno) of the optical system (1200), the stroke length (LG3_stroke) of the third lens group (LG3), the total optical axis distance of the optical system (1200) TTL (mm), ImgH (mm), the maximum effective diameter (CA_Max), the minimum effective diameter (CA_Min), the average effective diameter (CA_Aver), the maximum center thickness (L_CT_max), the minimum center thickness (L_CT_min), the average center thickness (L_CT_aver) among the first to seventh lenses (301 to 307), the length in the Y-axis direction (TL_Y) of the optical system (1200), the length in the X-axis direction (TL_X) of the optical system (1200), etc.

[0365]

[0366]

[0367] Hereinafter, the center thicknesses of the first to seventh lenses (301 to 307) are represented as CT1 to CT7, the edge thicknesses at the ends of the effective areas of each lens are represented as ET1 to ET7, and the center gap between two adjacent lenses is represented as CG1 to CG6. The back focal length (BFL) is the optical axis distance from the image sensor (500) to the center of the last lens. The TTL is the optical axis distance from the center of the first surface (S1) of the first lens (301) to the upper surface of the image sensor (500).

[0368]

[0369] When comparing the absolute values ​​of the curvature radii of each lens, the curvature radii of the thirteenth surface (S13) of the seventh lens (307) on the optical axis (OA) may be the largest among the lenses, and the curvature radii of the eighth surface (S8) of the fourth lens (304) may be the smallest among the lenses. The absolute value of the curvature radii of the first surface (S1) of the first lens (301) may be smaller than the absolute value of the curvature radii of the second surface (S2). The absolute value of the curvature radii of the fifth surface (S5) of the third lens (303) may be smaller than the absolute value of the curvature radii of the sixth surface (S6). The absolute value of the curvature radii of the seventh surface (S7) of the fourth lens (304) may be larger than the absolute value of the curvature radii of the eighth surface (S8). The absolute value of the curvature radius of the ninth surface (S9) of the fifth lens (305) may be smaller than the absolute value of the curvature radius of the tenth surface (S10). The absolute value of the curvature radius of the eleventh surface (S11) of the sixth lens (306) may be smaller than the absolute value of the curvature radius of the twelfth surface (S12). The absolute value of the curvature radius of the thirteenth surface (S13) of the seventh lens (307) may be larger than the absolute value of the curvature radius of the fourteenth surface (S14).

[0370]

[0371] Condition 1: 0.5 < |L1R1 / L1R2| < 1

[0372] Condition 2: 3 < |L3R1 / L3R2| < 5

[0373] Condition 3: 0.5 < |L4R1 / L4R2| < 1

[0374] Condition 4: 0.5 < |L5R1 / L5R2| < 1

[0375] Condition 5: 0.5 < |L6R1 / L6R2| < 1

[0376] Condition 6: 2.5 < |L7R1 / L7R2| < 3

[0377]

[0378] When describing the central thickness of the lenses based on the optical axis, the central thickness (CT2) of the second lens (302) is the largest among the lenses, and the central thicknesses (CT6) of the first lens (301) and the sixth lens (306) are the smallest among the lenses. The difference between the maximum central thickness and the minimum central thickness among the lenses may be in the range of 5 mm or more and 6 mm or less.

[0379] The central thickness of each lens may satisfy any one of the following conditions:

[0380] Condition 1: CT2, CT3, CT4, CT5, CT7 > CT1 = CT6

[0381] Condition 2: CT2 > CT1, CT3, CT4, CT5, CT6, CT7

[0382] Condition 3: CT2, CT4 > CT3 > CT1, CT5, CT6, CT7

[0383] Condition 4: CT2 > CT4 > CT1, CT3, CT5, CT6, CT7

[0384] Condition 5: CT2, CT3, CT4, CT7 > CT5 > CT1, CT6

[0385] Condition 6: CT2, CT3, CT4 > CT7 > CT1, CT5, CT6

[0386]

[0387] When zooming, the distance (CG1) between the first lens (301) and the second lens (302), the distance (CG2) between the second lens (302) and the third lens (303), the distance (CG3) between the third lens (303) and the fourth lens (304), the distance (CG4) between the fourth lens (304) and the fifth lens (305), and the distance (CG6) between the sixth lens (306) and the seventh lens (307) do not change, while the distance (CG5) between the fifth lens (305) and the sixth lens (306) can change. Among the center distances between the lenses that do not change, the distance (CG4) between the fourth lens (304) and the fifth lens (305) can be the maximum, and the distance (CG3) between the third lens (303) and the fourth lens (304) can be the minimum. The difference between the maximum center spacing and the minimum center spacing among the lens spacings may be 1.0 mm or more, for example, in the range of 1.0 mm to 1.5 mm.

[0388] The center spacing between each lens can satisfy the conditions below.

[0389] Condition 1: CG4 > CG1 > CG2, CG3, CG6

[0390] Condition 2: CG1, CG4 > CG2 > CG3, CG6

[0391] Condition 3: CG1, CG2, CG4, CG6 > CG3

[0392] Condition 4: CG4 > CG1, CG2, CG3, CG6

[0393] Condition 5: CG1, CG2, CG4 > CG6 > CG3

[0394]

[0395] Regarding the effective diameter, the lens having the maximum effective diameter may be the first lens (301). Here, the effective diameter is the average of the effective diameters of the object-side surface and the sensor-side surface of each lens. The lens surface having the maximum effective diameter may be the first surface (S1) of the first lens (301). The lens having the minimum effective diameter may be the fourth lens (304). The lens surface having the minimum effective diameter may be the eighth surface (S8) of the fourth lens (304). The effective diameters of the first to seventh lenses (301-307) may be smaller than the diagonal length of the image sensor (500).

[0396] The effective diameter of each lens can satisfy any one of the conditions below.

[0397] Condition 1: CA_L1 > CA_L2, CA_L3, CA_L4, CA_L5, CA_L6, CA_L7

[0398] Condition 2: CA_L1 > CA_L2 > CA_L3, CA_L4, CA_L5, CA_L6, CA_L7

[0399] Condition 3: CA_L1, CA_L2, CA_L7 > CA_L3 > CA_L4, CA_L5, CA_L6

[0400] Condition 4: CA_L1, CA_L2, CA_L3, CA_L5, CA_L6, CA_L7 > CA_L4

[0401] Condition 5: CA_L1, CA_L2, CA_L3, CA_L6, CA_L7 > CA_L5 > CA_L4

[0402] Condition 6: CA_L1, CA_L2, CA_L3, CA_L7 > CA_L6 > CA_L4, CA_L5

[0403] Condition 7: CA_L1, CA_L2 > CA_L7 > CA_L3, CA_L4, CA_L5, CA_L6

[0404]

[0405] In terms of refractive index, the refractive index of the second lens (302) may be the highest among the lenses and may be greater than 1.6, for example, greater than 1.7. Any one of the first lens (301), the third lens (303), and the sixth lens (306) may have the lowest refractive index among the lenses. For example, the refractive index of any one of the first lens (301), the third lens (303), and the sixth lens (306) may be the lowest among the lenses and may be less than 1.6, for example, less than 1.57. The difference between the maximum refractive index and the minimum refractive index may be 0.1 or more.

[0406] The refractive index of each lens can satisfy any of the conditions below.

[0407] Condition 1: n2, n4, n5, n7 > n1 = n3 = n6

[0408] Condition 2: n2 > n1, n3, n4, n5, n6, n7

[0409] Condition 3: n2 > n4 = n5 = n7 > n1, n3, n6

[0410]

[0411] Comparing the Abbe numbers, the Abbe numbers of the first lens (301), the third lens (303), and the sixth lens (306) are the largest among the lenses and may be 50 or more. The Abbe numbers of the fourth lens (304), the fifth lens (305), and the seventh lens (307) are the smallest among the lenses and may be 20 or less. The difference between the maximum refractive index and the minimum Abbe number may be 30 or more.

[0412] The Abbe number of each lens can satisfy any of the conditions below.

[0413] Condition 1: v1 = v3 = v6 > v2, v4, v5, v7

[0414] Condition 2: v1, v3, v6 > v2 > v4, v5, v7

[0415] Condition 3: v1, v2, v3, v6 > v4 = v5 = v7

[0416]

[0417] The focal lengths (F1, F3, F5, F6) of the first, third, fifth, and sixth lenses (301, 303, 305, and 306) may have a positive (+) sign. The first, third, fifth, and sixth lenses (301, 303, 305, and 306) may have a positive (+) refractive power. The focal lengths (F4, F7) of the fourth and seventh lenses (304, 307) may have a negative (-) sign. The fourth and seventh lenses (304, 307) may have a negative (-) refractive power. When comparing the focal lengths in absolute values, the focal length of the sixth lens (306) is the largest among the lenses and may be 400 or more and 500 or less. The focal length of the fourth lens (304) is the smallest among the lenses, and the absolute value of the focal length of the fourth lens (304) may be 5 or more and 10 or less.

[0418] The absolute value of the focal length of each lens can satisfy any of the conditions below.

[0419] Condition 1: |f6| > |f1| > |f3|, |f4|, |f5|, |f7|

[0420] Condition 2: |f1|, |f5|, |f6|, |f7| > |f3| > |f4|

[0421] Condition 3: |f1|, |f3|, |f5|, |f6|, |f7| > |f4|

[0422] Condition 4: |f1|, |f6|, |f7| > |f5| > |f3|, |f4|

[0423] Condition 5: |f6| > |f1|, |f3|, |f4|, |f5|, |f7|

[0424] Condition 6: |f1|, |f6| > |f7| > |f3|, |f4|, |f5|

[0425]

[0426] The composite focal length (f_LG1) of the first lens group (LG1) can have a positive (+) sign. The first lens group (LG1) can have a positive (+) composite refractive power. The composite focal length (f_LG2) of the second lens group (LG2) can have a positive (+) sign. The second lens group (LG2) can have a positive (+) composite refractive power. The composite focal length (f_LG3) of the third lens group (LG3) can have a negative (-) sign. The third lens group (LG3) can have a negative (-) composite refractive power. Through this, light incident from the object side can move away from the optical axis direction and then gather again in the optical axis direction, thereby forming a stable optical path.

[0427] When comparing the absolute values ​​of the composite focal lengths of the first to third lens groups (LG1, LG2, LG3), the composite focal length of the first lens group (LG1) may be the largest, and the composite focal length of the second lens group (LG2) may be the smallest. The relationship between the composite focal lengths of the first to third lens groups (LG1, LG2, LG3) may satisfy |f_LG1| > |f_LG3| > |f_LG2|.

[0428]

[0429] The thickness (CT1) of the first lens (301) may be a difference of at least 1 time between the maximum thickness and the minimum thickness, for example, 1 to 1.5 times, and the center thickness (CT1) may be the maximum and the edge thickness (ET1) may be the minimum. The thickness (T3) of the third lens (303) may be the maximum at the center and the minimum at the edge, and the maximum thickness may be in the range of 1.5 to 2 times the minimum thickness. The thickness (T4) of the fourth lens (304) may be the minimum at the center and the maximum at the edge, and the maximum thickness may be in the range of 1 to 1.5 times the minimum thickness. The thickness (T5) of the fifth lens (305) may be the maximum at the center and the minimum at the edge, and the maximum thickness may be in the range of 1 to 1.5 times the minimum thickness. The thickness (T6) of the sixth lens (306) may be maximum at the center and minimum at the edge, and the maximum thickness is in the range of 1 to 1.5 times the minimum thickness. The thickness (T7) of the seventh lens (307) may be minimum at the center and maximum at the edge, and the maximum thickness is in the range of 1 to 1.5 times the minimum thickness.

[0430]

[0431] The thickness of each lens can satisfy any of the conditions below.

[0432] Condition 1: 1 < CT1 / ET1 < 1.5, 0.5 < ET1 / CT1 < 1

[0433] Condition 2: 1.5 < CT3 / ET3 < 2, 0.5 < ET3 / CT3 < 1

[0434] Condition 3: 0.5 < CT4 / ET4 < 1, 1 < ET4 / CT4 < 1.5

[0435] Condition 4: 1 < CT5 / ET5 < 1.5, 0.5 < ET5 / CT5 < 1

[0436] Condition 5: 1 < CT6 / ET6 < 1.5, 0.5 < ET6 / CT6 < 1

[0437] Condition 6: 0.5 < CT7 / ET7 < 1, 1 < ET7 / CT7 < 1.5

[0438] Condition 7: 1 < ΣCT / ΣET < 1.5, 0.5 < ΣET / ΣCT < 1

[0439]

[0440] Among the gaps (G1-G6) between the lenses, the gap (LG1) between the first and second lenses (301, 302) may be maximum in the center and minimum at the edge. The gap (LG2) between the second and third lenses (302, 303) may be minimum in the center and maximum at the edge. The gap (LG3) between the third and fourth lenses (303, 304) may be minimum in the center and maximum at the edge. The gap (G4) between the fourth and fifth lenses (304, 305) may be minimum in the edge and maximum at the center. The fifth gap (G5) between the fifth and sixth lenses (305, 306) may be maximum in the center and minimum at the edge. The sixth gap (G6) between the sixth and seventh lenses (306, 307) may be minimum in the center and maximum at the edge.

[0441]

[0442] Fig. 12 is a graph showing the aberration characteristics of the optical system according to the third embodiment. For example, Fig. 12 may be a graph showing the aberration characteristics in the first mode of the optical system according to the third embodiment. In the aberration graph of Fig. 12, spherical aberration (longitudinal spherical aberration), astigmatic field curves, and distortion are measured from left to right. In Fig. 12, the X-axis may represent the focal length (mm) and the degree of distortion (%), and the Y-axis may represent the height of the image. In addition, the graph for spherical aberration is a graph for light in wavelength bands of about 470 nm, about 501 nm, about 550 nm, about 610 nm, and about 650 nm, and the graphs for astigmatism and distortion are graphs for light in wavelength bands of about 550 nm. In the aberration diagram of Fig. 12, the closer each curve is to the Y-axis, the better the aberration correction function can be interpreted. It can be seen that the optical system (1200) according to the third embodiment has measured values ​​close to the Y-axis in almost all areas. In other words, the optical system (1200) according to the third embodiment has improved resolution and can have good optical performance not only in the center of the field of view (FOV) but also in the periphery.

[0443]

[0444] An optical system according to the fourth embodiment of the invention will be described.

[0445] FIG. 13 is a configuration diagram of an optical system according to the fourth embodiment of the present invention operating in the first mode, FIG. 14 is a configuration diagram of an optical system according to the fourth embodiment of the present invention operating in the second mode, FIG. 15 is a table showing aspherical coefficients of lenses in the optical system according to the fourth embodiment of the present invention, and FIG. 16 is a graph showing data on aberration characteristics of the optical system according to the fourth embodiment of the present invention operating in the first mode.

[0446] Referring to FIG. 13, the optical system (1300) includes a lens unit, and the lens unit may include first to seventh lenses (401 to 407). The first to seventh lenses (401 to 407) may be sequentially arranged along the optical axis (OA) of the optical system (1300). Light corresponding to information about an object may pass through the first to seventh lenses (401 to 407) and the filter (600) and be incident on the image sensor (500).

[0447] The first lens (401) may be positioned closest to the object side. The first lens (401) may be positioned furthest from the sensor side. The first lens (401) may have positive refractive power. The first lens (401) may include a plastic or glass material. For example, the first lens (401) may be provided as a plastic material.

[0448] The first surface (S1) on the object side of the first lens (401) may be convex with respect to the optical axis, and the second surface (S2) on the sensor side may be concave. The first lens (401) may have a meniscus shape in which the object side is convex. The first lens (401) may have a meniscus shape in which the sensor side is concave. The first lens (401) is made of a plastic material and may have an aspherical surface. The aspherical coefficients of the first surface (S1) and the second surface (S2) of the first lens (401) may be provided as L1S1 and L1S2 of FIG. 15. At least one or both of the first surface (S1) and the second surface (S2) of the first lens (401) may be provided without a critical point from the optical axis to the end of the effective area.

[0449]

[0450] The second lens (402) may be a prism lens. The second lens (402) may be a right-angle prism lens. The second lens (402) may be a light path control member. The second lens (402) may change the path of light incident from the outside. The second lens (402) may include a reflector and a prism. The second lens (402) may rotate the light path by 90 degrees. The second lens (402) includes an incident surface (S3) on which light is incident, a reflective surface (RS1) that reflects the incident light, and an exit surface (S4) that emits the reflected light. The reflective surface (RS1) has an inclination angle of 45 degrees and reflects the principal ray of the incident light at 90 degrees, thereby reflecting the incident light to the third lens (403). The second lens (402) can reflect light incident in the first direction (Y-axis direction) and change the path of the light to the second direction (X-axis direction).

[0451] The aperture (STOP) may be positioned between the second lens (402) and the third lens (403). The aperture may be positioned on the fourth surface (S4) on the sensor side of the second lens (402) or the fifth surface (S5) on the object side of the third lens (403). The aperture can reduce the TTL within the field of view range and enable miniaturization of the optical system. Accordingly, a decrease in the yield by weight of the optical system can be prevented and production efficiency can be improved.

[0452]

[0453] The third lens (403) may be arranged third from the object side. The third lens (403) may be arranged fifth from the sensor side. The third lens (403) may be arranged between the second lens (402) and the fourth lens (404). The third lens (403) may have positive refractive power. The third lens (403) may include a plastic or glass material. For example, the third lens (403) may be provided as a plastic material.

[0454] The fifth surface (S5) on the object side of the third lens (403) with respect to the optical axis may be convex, and the sixth surface (S6) on the sensor side may be convex. The third lens (403) may have a shape in which both sides are convex. The third lens (403) is made of a plastic material and may have an aspherical surface. The aspherical coefficients of the fifth surface (S5) and the sixth surface (S6) may be provided as L3S1 and L3S2 of FIG. 15. At least one or both of the fifth surface (S5) and the sixth surface (S6) of the third lens (403) may be provided without a critical point from the optical axis to the end of the effective area.

[0455]

[0456] The fourth lens (404) may be arranged fourth from the object side. The fourth lens (404) may be arranged fourth from the sensor side. The fourth lens (404) may be arranged between the third lens (403) and the fifth lens (405). The fourth lens (404) may have negative (-) refractive power. The fourth lens (404) may include a plastic or glass material. For example, the fourth lens (404) may be provided as a plastic material.

[0457] The seventh surface (S7) on the object side of the fourth lens (404) with respect to the optical axis may be convex, and the eighth surface (S8) on the sensor side may be concave. The fourth lens (404) may have a meniscus shape in which the object side is convex. The fourth lens (404) may have a meniscus shape in which the sensor side is concave. The fourth lens (404) is made of a plastic material and may have an aspherical surface. The aspherical coefficients of the seventh surface (S7) and the eighth surface (S8) may be provided as L4S1 and L4S2 of FIG. 15. At least one or both of the seventh surface (S7) and the eighth surface (S8) of the fourth lens (404) may be provided without a critical point from the optical axis to the end of the effective area.

[0458]

[0459] The fifth lens (405) may be arranged as the fifth lens from the object side. The fifth lens (405) may be arranged as the third lens from the sensor side. The fifth lens (405) may be arranged between the fourth lens (404) and the sixth lens (406). The fifth lens (405) may have positive (+) refractive power. The fifth lens (405) may include a plastic or glass material. For example, the fifth lens (405) may be provided as a plastic material.

[0460] With respect to the optical axis (OA), the ninth surface (S9) on the object side of the fifth lens (405) may be convex, and the tenth surface (S10) on the sensor side may be concave. The fifth lens (405) may have a meniscus shape in which the object side is convex. The fifth lens (405) may have a meniscus shape in which the sensor side is concave. The fifth lens (405) is made of a plastic material and may have an aspherical surface. The aspherical coefficients of the ninth surface (S9) and the tenth surface (S10) may be provided as L5S1 and L5S2 of FIG. 15. At least one or both of the ninth surface (S9) and the tenth surface (S10) of the fifth lens (405) may be provided without a critical point from the optical axis to the end of the effective area.

[0461]

[0462] The sixth lens (406) may be arranged as the sixth lens from the object side. The sixth lens (406) may be arranged as the second lens from the sensor side. The sixth lens (406) may be arranged between the fifth lens (405) and the seventh lens (407). The sixth lens (406) may have negative (-) refractive power. The sixth lens (406) may include a plastic or glass material. For example, the sixth lens (406) may be provided as a plastic material.

[0463] With respect to the optical axis (OA), the object-side eleventh surface (S11) of the sixth lens (406) may be concave, and the sensor-side twelfth surface (S12) may be concave. The sixth lens (406) may have a concave shape on both sides. The sixth lens (406) may be made of a plastic material and may have an aspherical surface. The aspherical coefficients of the eleventh surface (S11) and the twelfth surface (S12) may be provided as L6S1 and L6S2 of FIG. 15.

[0464] The eleventh surface (S11) of the sixth lens (406) may have a critical point from the optical axis to the end of the effective area. When the eleventh surface (S11) has a critical point, it may be located in a range of 40% to 60%, preferably 45% to 55%, of the effective radius from the optical axis. The critical point of the eleventh surface (S11) may be located in a range of 0.5 mm to 2.0 mm, preferably 1.0 mm to 1.5 mm from the optical axis. The critical point of the eleventh surface (S11) may be a point where the sign of the gradient value with respect to the optical axis and the direction perpendicular to the optical axis changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the gradient value is 0. In addition, the critical point of the eleventh surface (S11) may be a point where the gradient value of a tangent passing through the lens surface increases and then decreases, or a point where the gradient value decreases and then increases. The twelfth surface (S12) of the sixth lens (106) can be provided without a critical point from the optical axis to the end of the effective area.

[0465]

[0466] The seventh lens (407) may be arranged closest to the sensor side. The seventh lens (407) may be arranged farthest from the object side. The seventh lens (407) may be arranged between the sixth lens (406) and the filter (600). The seventh lens (407) may be arranged between the sixth lens (406) and the image sensor (500). The seventh lens (407) may have positive (+) refractive power. The seventh lens (407) may include a plastic or glass material. For example, the seventh lens (407) may be provided with a plastic material.

[0467] With respect to the optical axis (OA), the 13th surface (S13) on the object side of the seventh lens (407) may be convex, and the 14th surface (S14) on the sensor side may be concave. The 7th lens (407) may have a meniscus shape in which the object side is convex. The 7th lens (407) may have a meniscus shape in which the sensor side is concave. The 7th lens (407) is made of a plastic material and may have an aspherical surface. The aspherical coefficients of the 13th surface (S13) and the 14th surface (S14) may be provided as L7S1 and L7S2 of FIG. 15. At least one or both of the 13th surface (S13) and the 14th surface (S14) of the 7th lens (407) may be provided without a critical point from the optical axis to the end of the effective area.

[0468]

[0469] LensSurfaceRadiusThicknessndvdClearAperture1S113.9501.5001.55056.0007.800 S254.8500.700 7.5202S3Infinity6.8001.72029.5007.420STOPS4Infinity5.290 6.6003S58.3201.1101.55056.0005.400 S6-18.1400.100 5.3704S736.4501.0301.68019.2005.300 S84.8001.380 5.0505S99.1601.3601.68019.2005.740S1077.080Variable(D1) 5.7606S11-22.5101.4101.55056.0005.880 S1217.7200.280 6.0407S137.4602.3001.68019.2006.170 S146.840Variable(D2) 6.780Filter Infinity Infinity Image Infinity

[0470] Table 10 shows the surface number (Surface), radius of curvature (Radius), center thickness of each lens or distance between lens surfaces (Thickness), refractive index (Index,nd), Abbe number (Abbe,vd), clear aperture, and focal length of the lens according to the fourth embodiment of the present invention. At this time, the unit of the radius of curvature and thickness or distance may be mm.

[0471] In Table 10, the thickness of the second lens (402), which is a prism lens, may refer to the thickness along the optical axis (OA). For example, the thickness of the second lens (402) may refer to the sum of the thickness from the object side (S3) to the reflective surface (RS1) on the y-axis and the thickness from the reflective surface (RS1) to the sensor side (S4) on the x-axis. In addition, the thickness of the second lens (402) from the object side (S3) to the reflective surface (RS1) on the y-axis and the thickness of the second lens (402) from the reflective surface (RS1) to the sensor side (S4) on the x-axis may be the same. According to a variation, the thickness of the second lens (402) from the object side (S3) to the reflective surface (RS1) on the y-axis and the thickness of the second lens (402) from the reflective surface (RS1) to the sensor side (S4) on the x-axis may be different.

[0472]

[0473] Mode 1 Mode 2 D11.5402.650 D24.4103.300

[0474] Table 11 shows the distances (D1, D2) between lenses that are variable when the optical system according to the fourth embodiment of the present invention operates in one of the first and second modes. Here, the first mode may refer to a case where an object located at infinity is photographed, and the second mode may refer to a case where an object located at a close distance (macroscopic) (e.g., within 1000 mm) is photographed.

[0475] In the optical system according to the fourth embodiment of the present invention, the distance between adjacent lens groups may change during the process of changing the magnification from the first mode to the second mode. The first and second lens groups (LG1, LG2) may be fixed, and the third lens group (LG3) may be movable. The first and second lens groups (LG1, LG2) may be fixed groups, and the third lens group (LG3) may be a movable group.

[0476] When operating from the first mode to the second mode, the distance (D1) between the second lens group (LG2) and the third lens group (LG3) may increase, and the distance (D2) between the third lens group (LG3) and the image sensor (500) may decrease.

[0477] When operating from the second mode to the first mode, the distance (D1) between the second lens group (LG2) and the third lens group (LG3) may decrease, and the distance (D2) between the third lens group (LG3) and the image sensor (500) may increase.

[0478] The stroke length of the third lens group (LG3) can satisfy 1.0 mm to 1.5 mm, and preferably, can satisfy about 1.110 mm.

[0479]

[0480] EFL(F)20.750EPD7.800BFL_14.410SD10.500BFL_23.300TD24.790FOV_121.900TD_LG19.000FOV_222.300TD_LG24.980 f133.860TD_LG33.990f2-f_LG133.860f310.620f_LG221.440f4-8.260f_LG3-16.940f515.190LG3_stroke1.110f6-17. 960TTL29.200f7245.460ImgH8.200ET11.090ΣCT15.510ET26.800ΣCG9.290ET30.500CA_Max7.660ET41.630CA_Min5.17 5ET50.940CA_Aver6.202ET61.970L_CT_max6.800ET72.310L_CT_min1.030Fno2.700L_CT_aver2.216TL_Y5.6TL_X23.61

[0481] Table 12 shows the items of the mathematical formulas described above in the optical system (1300) of the present embodiment, including the effective focal length (EFL (F) (mm)) in the first mode of the optical system (1300), the distance from the sensor side of the last lens to the image sensor (BFL_1 (mm)) in the first mode, the distance from the sensor side of the last lens to the image sensor (BFL_2 (mm)) in the second mode, the angle of view (FOV_1 (degree)) in the first mode, the angle of view (FOV_2 (degree)) in the second mode, the focal lengths (f1 to f7) (mm) of the first to seventh lenses (401 to 407), the edge thickness (ET1 to ET7), the lengths (TD_LG1, TD_LG2, TD_LG3) of each lens group in the optical axis direction, the focal lengths (f_LG1, f_LG2, f_LG3) (mm) of the first to third lens groups (LG1, LG2, LG3), The size of the entrance pupil (EPD (mm)), the optical axis distance (SD (mm)) from the aperture (STOP) to the fourteenth surface (S14), the optical axis distance (TD (mm)) from the first lens (401) to the seventh lens (407), the brightness (Fno) of the optical system (1300), the stroke length (LG3_stroke) of the third lens group (LG3), the total optical axis distance of the optical system (1300) TTL (mm), ImgH (mm), the maximum effective diameter (CA_Max), the minimum effective diameter (CA_Min), the average effective diameter (CA_Aver), the maximum center thickness (L_CT_max), the minimum center thickness (L_CT_min), the average center thickness (L_CT_aver) among the first to seventh lenses (401 to 407), the length in the Y-axis direction (TL_Y) of the optical system (1300), the length in the X-axis direction (TL_X) of the optical system (1300), etc.

[0482]

[0483] Hereinafter, the center thicknesses of the first to seventh lenses (401 to 407) are represented by CT1 to CT7, the edge thicknesses at the ends of the effective areas of each lens are represented by ET1 to ET7, and the center gap between two adjacent lenses is represented by CG1 to CG6. The back focal length (BFL) is the optical axis distance from the image sensor (500) to the center of the last lens. The TTL is the optical axis distance from the center of the first surface (S1) of the first lens (401) to the upper surface of the image sensor (500).

[0484]

[0485] When comparing the absolute values ​​of the curvature radii of each lens, the curvature radii of the tenth surface (S10) of the fifth lens (405) on the optical axis (OA) may be the largest among the lenses, and the curvature radii of the eighth surface (S8) of the fourth lens (404) may be the smallest among the lenses. The absolute value of the curvature radii of the first surface (S1) of the first lens (401) may be smaller than the absolute value of the curvature radii of the second surface (S2). The absolute value of the curvature radii of the fifth surface (S5) of the third lens (403) may be smaller than the absolute value of the curvature radii of the sixth surface (S6). The absolute value of the curvature radii of the seventh surface (S7) of the fourth lens (404) may be larger than the absolute value of the curvature radii of the eighth surface (S8). The absolute value of the curvature radius of the ninth surface (S9) of the fifth lens (405) may be smaller than the absolute value of the curvature radius of the tenth surface (S10). The absolute value of the curvature radius of the eleventh surface (S11) of the sixth lens (406) may be larger than the absolute value of the curvature radius of the twelfth surface (S12). The absolute value of the curvature radius of the thirteenth surface (S13) of the seventh lens (407) may be larger than the absolute value of the curvature radius of the fourteenth surface (S14).

[0486]

[0487] Condition 1: 0.1 < |L1R1 / L1R2| < 0.5

[0488] Condition 2: 0.1 < |L3R1 / L3R2| < 0.5

[0489] Condition 3: 5 < |L4R1 / L4R2| < 10

[0490] Condition 4: 0.1 < |L5R1 / L5R2| < 0.5

[0491] Condition 5: 1 < |L6R1 / L6R2| < 1.5

[0492] Condition 6: 1 < |L7R1 / L7R2| < 1.5

[0493]

[0494] When describing the central thickness of the lenses based on the optical axis, the central thickness (CT2) of the second lens (402) is the largest among the lenses, and the central thickness (CT4) of the fourth lens (404) is the smallest among the lenses. The difference between the maximum and minimum central thicknesses among the lenses may be in the range of 5 mm or more and 6 mm or less.

[0495] The central thickness of each lens may satisfy any one of the following conditions:

[0496] Condition 1: CT2, CT7 > CT1 > CT3, CT4, CT5, CT6

[0497] Condition 2: CT2 > CT1, CT3, CT4, CT5, CT6, CT7

[0498] Condition 3: CT1, CT2, CT6, CT7, CT5 > CT3 > CT4

[0499] Condition 4: CT1, CT2, CT3, CT5, CT6, CT7 > CT4

[0500] Condition 5: CT1, CT2, CT6, CT7 > CT5 > CT3, CT4

[0501] Condition 6: CT1, CT2, CT7 > CT6 > CT3, CT4, CT5

[0502] Condition 7: CT2 > CT7 > CT1, CT3, CT4, CT5, CT6

[0503]

[0504] When zooming, the distance (CG1) between the first lens (401) and the second lens (402), the distance (CG2) between the second lens (402) and the third lens (403), the distance (CG3) between the third lens (403) and the fourth lens (404), the distance (CG4) between the fourth lens (404) and the fifth lens (405), and the distance (CG6) between the sixth lens (406) and the seventh lens (407) do not change, while the distance (CG5) between the fifth lens (405) and the sixth lens (406) can change. Among the center distances between the lenses that do not change, the distance (CG2) between the second lens (402) and the third lens (403) can be the maximum, and the distance (CG3) between the third lens (403) and the fourth lens (404) can be the minimum. The difference between the maximum center spacing and the minimum center spacing among the lens spacings may be 5 mm or more, for example, in the range of 5 mm to 5.5 mm.

[0505] The center spacing between each lens can satisfy the conditions below.

[0506] Condition 1: CG2 > CG1 > CG3, CG4, CG6

[0507] Condition 2: CG2 > CG1, CG3, CG4, CG6

[0508] Condition 3: CG1, CG2, CG4 > CG3 > CG6

[0509] Condition 4: CG1, CG2 > CG4 > CG3, CG6

[0510] Condition 5: CG1, CG2, CG3, CG4 > CG6

[0511]

[0512] Regarding the effective diameter, the lens having the maximum effective diameter may be the first lens (401). Here, the effective diameter is the average of the effective diameters of the object-side surface and the sensor-side surface of each lens. The lens surface having the maximum effective diameter may be the first surface (S1) of the first lens (401). The lens having the minimum effective diameter may be the fourth lens (404). The lens surface having the minimum effective diameter may be the eighth surface (S8) of the fourth lens (404). The effective diameters of the first to seventh lenses (401-407) may be greater than the diagonal length of the image sensor (500).

[0513] The effective diameter of each lens can satisfy any one of the conditions below.

[0514] Condition 1: CA_L1 > CA_L2, CA_L3, CA_L4, CA_L5, CA_L6, CA_L7

[0515] Condition 2: CA_L1 > CA_L2 > CA_L3, CA_L4, CA_L5, CA_L6, CA_L7

[0516] Condition 3: CA_L1, CA_L2, CA_L6, CA_L5, CA_L7 > CA_L3 > CA_L4

[0517] Condition 4: CA_L1, CA_L2, CA_L3, CA_L5, CA_L6, CA_L7 > CA_L4

[0518] Condition 5: CA_L1, CA_L2, CA_L6, CA_L7 > CA_L5 > CA_L3, CA_L4

[0519] Condition 6: CA_L1, CA_L2, CA_L7 > CA_L6 > CA_L3, CA_L4, CA_L5

[0520] Condition 7: CA_L1, CA_L2 > CA_L7 > CA_L3, CA_L4, CA_L5, CA_L6

[0521]

[0522] In terms of refractive index, the refractive index of the second lens (402) may be the highest among the lenses and may be greater than 1.6, for example, greater than 1.7. Any one of the first lens (401), the third lens (403), and the sixth lens (406) may have the lowest refractive index among the lenses. For example, the refractive index of any one of the first lens (401), the third lens (403), and the sixth lens (406) may be the lowest among the lenses and may be less than 1.6, for example, less than 1.57. The difference between the maximum refractive index and the minimum refractive index may be 0.1 or more.

[0523] The refractive index of each lens can satisfy any of the conditions below.

[0524] Condition 1: n2, n4, n5, n7 > n1 = n3 = n6

[0525] Condition 2: n2 > n1, n3, n4, n5, n6, n7

[0526] Condition 3: n2 > n4 = n5 = n7 > n1, n3, n6

[0527]

[0528] Comparing the Abbe numbers, the Abbe numbers of the first lens (401), the third lens (403), and the sixth lens (406) are the largest among the lenses and may be 50 or more. The Abbe numbers of the fourth lens (404), the fifth lens (405), and the seventh lens (407) are the smallest among the lenses and may be 20 or less. The difference between the maximum refractive index and the minimum Abbe number may be 30 or more.

[0529] The Abbe number of each lens can satisfy any of the conditions below.

[0530] Condition 1: v1 = v3 = v6 > v2, v4, v5, v7

[0531] Condition 2: v1, v3, v6 > v2 > v4, v5, v7

[0532] Condition 3: v1, v2, v3, v6 > v4 = v5 = v7

[0533]

[0534] The focal lengths (F1, F3, F5, F7) of the first, third, fifth, and seventh lenses (401, 403, 405, and 407) may have a positive (+) sign. The first, third, fifth, and seventh lenses (401, 403, 405, and 407) may have a positive (+) refractive power. The focal lengths (F4, F6) of the fourth and sixth lenses (404, 406) may have a negative (-) sign. The fourth and sixth lenses (404, 406) may have a negative (-) refractive power. When comparing the focal lengths in absolute values, the focal length of the sixth lens (406) is the largest among the lenses and may be 200 or more and 300 or less. The focal length of the fourth lens (404) is the smallest among the lenses, and the absolute value of the focal length of the fourth lens (404) may be 5 or more and 10 or less.

[0535] The absolute value of the focal length of each lens can satisfy any of the conditions below.

[0536] Condition 1: |f7| > |f1| > |f3|, |f4|, |f5|, |f6|

[0537] Condition 2: |f1|, |f5|, |f6|, |f7| > |f3| > |f4|

[0538] Condition 3: |f1|, |f3|, |f5|, |f6|, |f7| > |f4|

[0539] Condition 4: |f1|, |f6|, |f7| > |f5| > |f3|, |f4|

[0540] Condition 5: |f1|, |f7| > |f6| > |f3|, |f4|, |f5|

[0541] Condition 6: |f7| > |f1|, |f3|, |f4|, |f5|, |f6|

[0542]

[0543] The composite focal length (f_LG1) of the first lens group (LG1) can have a positive (+) sign. The first lens group (LG1) can have a positive (+) composite refractive power. The composite focal length (f_LG2) of the second lens group (LG2) can have a positive (+) sign. The second lens group (LG2) can have a positive (+) composite refractive power. The composite focal length (f_LG3) of the third lens group (LG3) can have a negative (-) sign. The third lens group (LG3) can have a negative (-) composite refractive power. Through this, light incident from the object side can move away from the optical axis direction and then gather again in the optical axis direction, thereby forming a stable optical path.

[0544] When comparing the absolute values ​​of the composite focal lengths of the first to third lens groups (LG1, LG2, LG3), the composite focal length of the first lens group (LG1) may be the largest, and the composite focal length of the third lens group (LG3) may be the smallest. The relationship between the composite focal lengths of the first to third lens groups (LG1, LG2, LG3) may satisfy |f_LG1| > |f_LG2| > |f_LG3|.

[0545]

[0546] The thickness (CT1) of the first lens (401) may be a difference of at least 1 time between the maximum thickness and the minimum thickness, for example, in the range of 1 to 1.5 times, and the center thickness (CT1) may be the maximum and the edge thickness (ET1) may be the minimum. The thickness (T3) of the third lens (403) may be the maximum at the center and the minimum at the edge, and the maximum thickness may be in the range of 2 to 2.5 times the minimum thickness. The thickness (T4) of the fourth lens (404) may be the minimum at the center and the maximum at the edge, and the maximum thickness may be in the range of 1.5 to 2 times the minimum thickness. The thickness (T5) of the fifth lens (405) may be the maximum at the center and the minimum at the edge, and the maximum thickness may be in the range of 1 to 1.5 times the minimum thickness. The thickness (T6) of the sixth lens (406) may be minimum at the center and maximum at the edge, and the maximum thickness is in the range of 1 to 1.5 times the minimum thickness. The thickness (T7) of the seventh lens (407) may be minimum at the center and maximum at the edge, and the maximum thickness is in the range of 1 to 1.5 times the minimum thickness.

[0547]

[0548] The thickness of each lens can satisfy any of the conditions below.

[0549] Condition 1: 1 < CT1 / ET1 < 1.5, 0.5 < ET1 / CT1 < 1

[0550] Condition 2: 2 < CT3 / ET3 < 2.5, 0.1 < ET3 / CT3 < 0.5

[0551] Condition 3: 0.5 < CT4 / ET4 < 1, 1.5 < ET4 / CT4 < 2

[0552] Condition 4: 1 < CT5 / ET5 < 1.5, 0.5 < ET5 / CT5 < 1

[0553] Condition 5: 0.5 < CT6 / ET6 < 1, 1 < ET6 / CT6 < 1.5

[0554] Condition 6: 0.5 < CT7 / ET7 < 1, 1 < ET7 / CT7 < 1.5

[0555] Condition 7: 1 < ΣCT / ΣET < 1.5, 0.5 < ΣET / ΣCT < 1

[0556]

[0557] Among the gaps (G1-G6) between the lenses, the gap (LG1) between the first and second lenses (401, 402) may be maximum in the center and minimum at the edge. The gap (LG2) between the second and third lenses (402, 403) may be minimum in the center and maximum at the edge. The gap (LG3) between the third and fourth lenses (403, 404) may be minimum in the center and maximum at the edge. The gap (G4) between the fourth and fifth lenses (404, 405) may be minimum in the edge and maximum at the center. The fifth gap (G5) between the fifth and sixth lenses (405, 406) may be minimum in the center and maximum at the edge. The sixth gap (G6) between the sixth and seventh lenses (406, 407) may be maximum in the center and minimum at the edge.

[0558]

[0559] Fig. 16 is a graph showing the aberration characteristics of the optical system according to the fourth embodiment. For example, Fig. 16 may be a graph showing the aberration characteristics in the first mode of the optical system according to the fourth embodiment. In the aberration graph of Fig. 16, spherical aberration (longitudinal spherical aberration), astigmatic field curves, and distortion are measured from left to right. In Fig. 16, the X-axis may represent the focal length (mm) and the degree of distortion (%), and the Y-axis may represent the height of the image. In addition, the graph for spherical aberration is a graph for light in wavelength bands of about 470 nm, about 501 nm, about 550 nm, about 610 nm, and about 650 nm, and the graphs for astigmatism and distortion are graphs for light in wavelength bands of about 550 nm. In the aberration diagram of Fig. 16, the closer each curve is to the Y-axis, the better the aberration correction function can be interpreted. It can be seen that the optical system (1300) according to the fourth embodiment has measured values ​​close to the Y-axis in almost all areas. In other words, the optical system (1300) according to the fourth embodiment has improved resolution and can have good optical performance not only in the center of the field of view (FOV) but also in the periphery.

[0560]

[0561] The optical systems (1000 to 1300) according to the first to fourth embodiments disclosed above can satisfy at least one or two or more of the mathematical equations described below. Accordingly, the optical systems (1000 to 1300) according to the first to fourth embodiments can have improved optical characteristics. For example, when the optical systems (1000 to 1300) satisfy at least one mathematical equation, the optical systems (1000 to 1300) can effectively control aberration characteristics such as chromatic aberration and distortion aberration, and can have good optical performance not only at the center but also at the periphery of the field of view (FOV). In addition, the optical systems (1000 to 1300) can have improved resolution. In addition, the thickness of the lens on the optical axis (OA) and the spacing between adjacent lenses on the optical axis (OA) described in the mathematical equations may refer to the first to fourth embodiments disclosed above.

[0562]

[0563] [Mathematical Formula 1]

[0564] 1 < TD_LG2 / TD_LG3 < 5

[0565] Mathematical expression 1 can establish the relationship between the length (TD_LG2) of the second lens group (LG2) and the length (TD_LG3) of the third lens group (LG3) in the optical axis direction. Mathematical expression 1 is a condition for reducing aberration and improving optical performance.

[0566] The second lens group (LG2) and the third lens group (LG3) satisfying mathematical expression 1 can appropriately correct astigmatism and coma aberration. In addition, the overall length of the zoom optical system having an appropriate zoom ratio can be reduced. In the first to fourth embodiments of the present invention, mathematical expression 1 can preferably satisfy 1.2 < TD_LG2 / TD_LG3 < 2.5.

[0567]

[0568] [Equation 2]

[0569] 15 < EFL(F) < 25

[0570] In mathematical expression 2, EFL(F) is the total focal length of the optical system (1000 to 1300) in the first mode. Mathematical expression 2 is a condition for limiting zoom optical performance. If it exceeds the upper limit of mathematical expression 2, it is difficult to secure optical performance due to chromatic aberration, and the amount of movement of each lens group increases significantly during zooming, making mechanical miniaturization difficult. If it is less than the lower limit of mathematical expression 2, there is a problem that the sensitivity of the entire optical system increases. A zoom optical system satisfying mathematical expression 2 can secure practically useful optical performance. Mathematical expression 2 can preferably satisfy 18 < EFL(F) < 23 in the first to fourth embodiments.

[0571]

[0572] [Equation 3]

[0573] 1 < BFL_1 < 8

[0574] In mathematical expression 3, BFL is the optical axis distance from the image sensor (500) to the center of the sensor side of the last lens in the first mode. When mathematical expression 3 is satisfied, the installation space of the filter (600) and the cover glass can be secured, the assemblability of the components can be improved through the gap between the image sensor (500) and the last lens, and the joint reliability can be improved. In the first to fourth embodiments, mathematical expression 3 can preferably satisfy 4 < BFL_1 < 7. When the BFL is less than the range of mathematical expression 3, some of the light traveling to the image sensor may not be transmitted to the image sensor, which may cause a decrease in resolution. When the BFL exceeds the range of mathematical expression 3, stray light may be introduced, which may deteriorate the aberration characteristics of the optical system.

[0575]

[0576] [Equation 4]

[0577] 20 < Ave_ABV < 50

[0578] In mathematical expression 4, Ave_ABV is the average of the Abbe numbers of the lenses included in the optical system (1000 to 1300). When mathematical expression 4 is satisfied, optical performance can be improved by appropriately setting factors affecting chromatic aberration. In the first to fourth embodiments, mathematical expression 4 can preferably satisfy 30 < Ave_ABV < 40.

[0579]

[0580] [Equation 5]

[0581] 1.5 < Ave_Ind < 1.7

[0582] In mathematical expression 5, Ave_Ind is the average of the refractive indices of the lenses included in the optical system (1000 to 1300). When mathematical expression 5 is satisfied, optical performance can be improved by appropriately setting factors affecting chromatic aberration. In the first to fourth embodiments, mathematical expression 4 preferably satisfies 1.62 < Ave_Ind < 1.68.

[0583]

[0584] [Equation 6]

[0585] 0.2 < |f_LG2 / f_LG3| < 3

[0586] Mathematical expression 6 can set the relationship between the focal length (f_LG2) of the second lens group (LG2) and the focal length (f_LG3) of the third lens group (LG3). Mathematical expression 6 is a condition for reducing aberration and improving optical performance. The second lens group (LG2) and the third lens group (LG3) that satisfy Mathematical expression 6 can appropriately correct astigmatism and coma. Mathematical expression 6 can preferably satisfy 0.5 < |f_LG2 / f_LG3| < 1.5 in the first to fourth embodiments.

[0587]

[0588] [Equation 7]

[0589] 10 < |f_LG3| < 40

[0590] In mathematical expression 7, f_LG3 is the focal length of the third lens group (LG3). Mathematical expression 7 is a condition for reducing aberration and improving optical performance. Mathematical expression 7 can preferably satisfy 15 < |f_LG3| < 35 in the first to fourth embodiments.

[0591]

[0592] [Equation 8]

[0593] 0.1 < LG3_stroke < 2

[0594] Mathematical expression 8 can set the range of the stroke length (LG3_stroke) of the third lens group (LG3). If it exceeds the upper limit of Mathematical expression 8, the stroke length of the third lens group (LG3) increases during focusing, making it difficult to miniaturize the optical system. If it is less than the lower limit of Mathematical expression 8, the focusing performance of the optical system may deteriorate. Mathematical expression 8 can preferably satisfy 0.3 < LG3_stroke < 1.5 in the first to fourth embodiments.

[0595]

[0596] [Equation 9]

[0597] 20 < F1 < 150

[0598] In mathematical expression 9, F1 is the focal length of the first lens (101 to 401). When mathematical expression 9 is satisfied, the optical system (1000 to 1300) can have a set angle of view and an appropriate focal length, and can set the angle of view to be large within an appropriate TTL range. When it is below the lower limit of mathematical expression 9, the effective diameter or TTL of the lenses may become long, which may cause a problem in that the imaging lens system becomes large. When it is above the upper limit of mathematical expression 9, the influence of the first lens (101 to 401) in the entire optical system becomes small, and the refractive power of the lenses needs to be increased, which causes a problem in that it is difficult to correct spherical aberration or distortion aberration. In the first to fourth embodiments, mathematical expression 9 may preferably satisfy 30 < F1 < 100.

[0599]

[0600] [Equation 10]

[0601] 1 < CT1 < 2

[0602] In mathematical expression 10, CT1 is the central thickness of the first lens (101 to 401). When mathematical expression 10 is satisfied, the thickness of the optical system (1000 to 1300) in the first direction (y-axis direction) can be prevented from increasing, and a miniaturized optical system can be implemented. In the first to fourth embodiments, mathematical expression 10 preferably satisfies 1.3 < CT1 < 1.8.

[0603]

[0604] [Equation 11]

[0605] 20 < TTL < 40

[0606] In mathematical expression 11, TTL (Total track length) means the distance (mm) from the center of the first surface (S1) of the first lens (101 to 401) to the upper surface of the image sensor (500) on the optical axis (OA). In the first to fourth embodiments, mathematical expression 11 can preferably satisfy 25 < TTL < 35.

[0607]

[0608] [Equation 12]

[0609] 5 < ImgH < 10

[0610] In mathematical expression 12, ImgH represents the maximum diagonal length of the image sensor (500). Mathematical expression 12 can set the diagonal size (ImgH) of the image sensor (500) and provide an optical system having a large mobile image sensor size. In the first to fourth embodiments, mathematical expression 12 can preferably satisfy 7 < ImgH < 9.

[0611]

[0612] [Equation 13]

[0613] 1 < Fno < 5

[0614] Mathematical expression 13 can set the range of Fno of the optical system (1000 to 1300). When mathematical expression 13 is satisfied, an image with an appropriate brightness can be provided, and a large amount of light can be received by the image sensor. In the first to fourth embodiments, mathematical expression 13 can preferably satisfy 2 < Fno < 3.

[0615]

[0616] [Equation 14]

[0617] 20 < FOV_1 < 30

[0618] In mathematical expression 14, the range of the angle of view (FOV_1) in the first mode can be set. In mathematical expression 14, an angle of view suitable for a mobile optical system can be provided. In the first to fourth embodiments, the FOV can preferably satisfy 20 < FOV_1 < 25.

[0619]

[0620] [Equation 15]

[0621] 2 < TTL / CA_max < 5

[0622] In mathematical expression 15, CA_max means the largest effective diameter (mm) among the object-side and sensor-side of a plurality of lenses, and TTL (Total track length) means the distance (mm) from the vertex of the first surface (S1) of the first lens (101 to 401) to the upper surface of the image sensor (500) on the optical axis (OA). Mathematical expression 15 sets the relationship between the total optical axis length of the optical system and the maximum effective diameter, thereby providing an improved mobile optical system. In the first to fourth embodiments, mathematical expression 15 can preferably satisfy 3.5 < TTL / CA_max < 4.

[0623]

[0624] [Equation 16]

[0625] 2 < TTL / ImgH < 5

[0626] In mathematical expression 16, TTL (Total track length) means the distance (mm) on the optical axis (OA) from the vertex of the first surface (S1) of the first lens to the upper surface of the image sensor (500), and ImgH means the maximum diagonal length of the image sensor (500). When mathematical expression 16 is satisfied, the optical system (1000 to 1300) can have TTL for application to the mobile image sensor (500), thereby providing more improved image quality. When it is less than the lower limit of mathematical expression 2, the refractive power of the lenses needs to be increased, making it difficult to correct spherical aberration or distortion aberration, and when it is more than the upper limit of mathematical expression 2, the effective diameter or TTL of the lenses may become long, which may cause a problem in that the imaging lens system becomes large. In the first to fourth embodiments, mathematical expression 16 can preferably satisfy 3 < TTL / ImgH < 3.8.

[0627]

[0628] [Equation 17]

[0629] 2 < EFL(F) / ImgH < 4

[0630] In mathematical expression 17, EFL(F) is the total effective focal length of the optical system (1000 to 1300) in the first mode, and ImgH means the maximum diagonal length of the image sensor (500). When mathematical expression 17 is satisfied, the mobile image sensor (500) can have improved aberration characteristics in its size. In the first to fourth embodiments, mathematical expression 17 can preferably satisfy 2.2 < EFL(F) / ImgH < 2.8.

[0631]

[0632] [Equation 18]

[0633] 0.1 < ΣCT / TTL < 1

[0634] Mathematical expression 18 can set the relationship between the sum of the central thicknesses of the lenses (ΣCT) and the distance (TTL) from the vertex of the first surface (S1) of the first lens to the upper surface of the image sensor (500) on the optical axis (OA). If it exceeds the upper limit of Mathematical expression 18, the number of lenses increases and the movement of the movable lens group in the optical system may become disadvantageous. If it is less than the lower limit of Mathematical expression 18, the focusing performance of the optical system may deteriorate. In the first to fourth embodiments, Mathematical expression 18 can preferably satisfy 0.5 < ΣCT / TTL < 0.8.

[0635]

[0636] [Equation 19]

[0637] 0.1 < ΣCG / TTL < 1

[0638] Mathematical expression 19 can set the relationship between the sum of the spacings between adjacent lenses (ΣCG) and the distance (TTL) from the vertex of the first surface (S1) of the first lens to the upper surface of the image sensor (500) on the optical axis (OA). If the upper limit of Mathematical expression 19 is exceeded, the moving distance of the moving lens group in the lens optical system increases, which may increase the current consumption during focusing operation. If the lower limit of Mathematical expression 19 is less than the lower limit of Mathematical expression 19, the focusing performance of the optical system may deteriorate. In the first to fourth embodiments, Mathematical expression 19 may preferably satisfy 0.1 < ΣCG / TTL < 0.4.

[0639]

[0640] [Equation 20]

[0641] 1 < ΣCT / ΣCG < 5

[0642] Mathematical expression 20 can set the relationship between the sum of the central thicknesses of the lenses (ΣCT) and the sum of the spacings between adjacent lenses (ΣCT). If the upper limit of Mathematical expression 20 is exceeded, the number of lenses increases and the movement of the movable lens group in the optical system may become unfavorable. If the lower limit of Mathematical expression 20 is lower, the focusing performance may deteriorate. In the first to fourth embodiments, Mathematical expression 20 can preferably satisfy 1.5 < ΣCT / ΣCG < 3.5.

[0643]

[0644] [Equation 21]

[0645] 1 < CA_max / CA_min < 3

[0646] In mathematical expression 21, CA_max represents the maximum effective diameter among the object-side and sensor-side surfaces of the lenses, and CA_min represents the minimum effective diameter among the object-side and sensor-side surfaces of the lenses. When mathematical expression 21 is satisfied, the optical system can set a size for a slim and compact structure while maintaining optical performance. In the first to fourth embodiments, mathematical expression 21 can preferably satisfy 1.2 < CA_max / CA_min < 1.8.

[0647]

[0648] [Equation 22]

[0649] 0.1 < CA_max / ImgH < 2

[0650] In mathematical expression 22, CA_max represents the maximum effective diameter among the object-side and sensor-side surfaces of the lenses, and ImgH represents the maximum diagonal length of the image sensor (500). When mathematical expression 22 is satisfied, the optical system can maintain good optical performance and set a size for a slim and compact structure. In the first to fourth embodiments, mathematical expression 22 can preferably satisfy 0.8 < CA_max / ImgH < 1.2.

[0651]

[0652] [Equation 23]

[0653] 0.1 < CA_min / ImgH < 1

[0654] In mathematical expression 23, CA_min represents the minimum effective diameter among the object-side and sensor-side surfaces of the lenses, and ImgH represents the maximum diagonal length of the image sensor (500). When mathematical expression 23 is satisfied, the optical system can maintain good optical performance and set a size for a slim and compact structure. In the first to fourth embodiments, mathematical expression 23 can preferably satisfy 0.5 < CA_min / ImgH < 0.9.

[0655]

[0656] [Equation 24]

[0657] 0.5 < CG1 < 1.3

[0658] In mathematical expression 24, CG1 is the center distance between the first lens (101 to 401) and the second lens (102 to 402). If mathematical expression 24 is satisfied, improved OIS can be implemented through prism tilt. If it is below the lower limit of mathematical expression 24, OIS performance deteriorates, and there is a problem that interference occurs between adjacent lenses during OIS correction. If it exceeds the upper limit of mathematical expression 24, sensitivity increases during OIS operation, which may cause a problem of reduced resolution. Mathematical expression 24 can preferably satisfy 0.6 < CG1 < 1.1 in the first to fourth embodiments.

[0659]

[0660] [Equation 25]

[0661] 0.5 < CG2 < 5.5

[0662] In mathematical expression 25, CG2 is the center distance between the second lens (102 to 402) and the third lens (103 to 403). When mathematical expression 25 is satisfied, improved OIS can be implemented through prism tilt. When it is below the lower limit of mathematical expression 25, OIS performance deteriorates, and there is a problem of interference occurring between adjacent lenses during OIS correction. When it exceeds the upper limit of mathematical expression 25, tilt sensitivity increases during OIS operation, which may cause a problem of reduced resolution. In the first to third embodiments, mathematical expression 25 can preferably satisfy 0.7 < CG2 < 1.3. In the fourth embodiment, mathematical expression 25 can preferably satisfy 4 < CG2 < 5.5.

[0663]

[0664] [Equation 26]

[0665] 2 < (CG3~CG6)_max < 4

[0666] In mathematical expression 26, (CG3~CG6)_max is the maximum value among the center spacings of the lenses arranged on the sensor side of the second lens (102~402), which is a prism lens. Mathematical expression 26 is a condition for AF correction through movement of the lens group. If it is less than the lower limit of mathematical expression 26, there is a problem that the AF correction function is difficult to apply, and if it exceeds the upper limit of mathematical expression 26, a problem may occur that the sensitivity increases during AF operation and the performance around the optical axis deteriorates. In the first to fourth embodiments, mathematical expression 26 can preferably satisfy 2 < (CG3~CG6)_max < 3.5.

[0667]

[0668] [Equation 27]

[0669] 0.2 < TD_LG2 / ΣCT < 0.5

[0670] In mathematical expression 27, TD_LG2 is the length of the second lens group (LG2) in the optical axis direction, and ΣCT is the sum of the central thicknesses of the lenses. Mathematical expression 27 is a condition for AF correction through movement of the lens group. If it is below the lower limit of mathematical expression 27, there is a problem that the AF correction function is difficult to apply, and if it exceeds the upper limit of mathematical expression 27, a problem that the sensitivity increases during AF operation and the performance around the optical axis deteriorates may occur. In the first to fourth embodiments, mathematical expression 27 can preferably satisfy 0.3 < TD_LG2 / ΣCT < 0.5.

[0671]

[0672] [Equation 28]

[0673] L1R1 > 0

[0674] In mathematical expression 28, L1R1 is the radius of curvature of the object-side surface of the first lens (101, 201). Mathematical expression 28 is a condition for OIS correction by tilting the prism lens, and if mathematical expression 28 is satisfied, the OIS correction sensitivity can be reduced.

[0675]

[0676] [Equation 29]

[0677] 0.2 < TL_Y / TL_X < 0.5

[0678] In mathematical expression 29, TL_Y is the length of the optical system (1000 to 1300) in the Y-axis direction, and TL_X is the length of the optical system (1000 to 1300) in the X-axis direction. When mathematical expression 29 is satisfied, the size of the optical system reflecting the optical system applicable to the zoom camera module and the designable lens size can be set. In the first to fourth embodiments, mathematical expression 29 can preferably satisfy 0.2 < TL_Y / TL_X < 0.3.

[0679]

[0680] [Equation 30]

[0681]

[0682] In mathematical expression 30, Z can represent Sag, which is the distance from any position on the aspherical surface to the vertex of the aspherical surface along the optical axis. Y can represent the distance from any position on the aspherical surface to the optical axis in the direction perpendicular to the optical axis. c can represent the curvature of the lens, and K can represent the conic constant. In addition, A, B, C, D, E, and F can represent aspheric coefficients.

[0683]

[0684] The optical systems (1000 to 1300) according to the first to fourth embodiments can satisfy at least one or two or more mathematical expressions from mathematical expressions 1 to 30. In this case, the optical systems (1000 to 1300) can have improved optical characteristics. Specifically, when the optical systems (1000 to 1300) satisfy at least one or two or more mathematical expressions from mathematical expressions 1 to 30, the optical systems (1000 to 1300) can have improved resolution and improve aberration and distortion characteristics. In addition, the optical systems (1000 to 1300) can secure a back focal length (BFL) for applying the image sensor (500), compensate for optical characteristic degradation due to temperature change, and minimize the gap between the last lens and the image sensor (500), thereby having good optical performance at the center and periphery of the field of view (FOV).

[0685]

[0686] Mathematical Formula Example 1 Example 2 Example 3 Example 4 Example 11 < TD_LG2 / TD_LG3 < 51.8571.7112.1171.248215 < EFL(F) < 2520.75020.75020.76020.75031 < BFL_1 < 86.1006.3704.7804.410420 < Ave_ABV < 5036.44336.44336.44336.44351.5 < Ave_Ind < 1.71.6301.6301.6301.63060.2 < |f_LG2 / f_LG3| < 30.7910.9100.5971.266710 < |f_LG3| < 4019.07015.10031.63016.94080.1 < LG3_stroke < 20.5700.4201.4801.110920 < F1 < 15040.69038.75099.82033.860101 < CT1 < 21.4301.3601.5001.5001120 < TTL < 4029.48028.97029.77029.200125 < ImgH < 108.2008.2008.2008.200131 < Fno < 52.7002.7002.7002.7001420 < FOV_1 < 3021.90021.90021.90021.900152 < TTL / CA_max < 53.8993.8403.9463.812162 < TTL / ImgH < 53.5953.5333.6303.561172 < EFL(F) / ImgH < 42.5302.5302.5322.530180.1 < ΣCT / TTL < 10.5660.5630.6370.531190.1 < ΣCG / TTL < 10.2270.2170.2030.318201 < ΣCT / ΣCG < 52.4952.5933.1321.670211 < CA_max / CA_min < 31.4391.4281.3181.480220.1 < CA_max / ImgH < 20.9220.9200.9200.934230.1 < CA_min / ImgH < 10.6410.6450.6980.631240.5 < CG1 < 1.31.0701.1401.2700.700250.5 < CG2 < 5.51.2001.2000.8005.290262 < (CG3~CG6)_max < 42.2502.2503.3302.650270.2 < TD_LG2 / ΣCT < 0.50.4430.4240.4580.32128L1R1 > 0 SatisfiedSatisfiedSatisfiedSatisfied290.2 < TL_Y / TL_X < 0.50.2440.2500.2610.237.

[0687] Table 13 shows the result values ​​for the mathematical expressions 1 to 29 described above in the optical systems (1000 to 1300) of the first to fourth embodiments. Referring to Table 13, it can be seen that the optical systems (1000 to 1300) satisfy at least one, two or more, or three or more of the mathematical expressions 1 to 29. In detail, it can be seen that the optical systems (1000 to 1300) according to the first to fourth embodiments satisfy all of the mathematical expressions 1 to 29. Accordingly, the optical systems (1000 to 1300) can have good optical performance at the center and periphery of the field of view (FOV) and can have excellent optical characteristics.

[0688]

[0689] Fig. 18 is an example of a mobile terminal having an optical system according to the present embodiment. As illustrated in Fig. 18, the mobile terminal (1500) may include a camera module (1520), a flash module (1530), and an autofocus device (1510) provided on one side or the rear side. Here, the autofocus device (1510) may include the surface-emitting laser element disclosed above as a light-emitting layer and a light receiving unit.

[0690] The flash module (1530) may include an emitter that emits light within it. The flash module (1530) may be operated by the camera of the mobile terminal or under user control. The camera module (1520) may include an image capturing function and an autofocus function. For example, the camera module (1520) may include an autofocus function using an image.

[0691] The autofocus device (1510) may include an autofocus function using a laser. The autofocus device (1510) may be primarily used in conditions where the autofocus function using the image of the camera module (1520) is degraded. In addition, although not shown in the drawing, at least one camera module may be additionally positioned on the front of the mobile terminal (1500). At least one of the camera modules within the mobile terminal may have a tele-type folded optical system as disclosed above.

[0692] The optical system or camera module according to the embodiment of the invention, the lens assembly according to various embodiments, can be applied to, for example, an electronic device employing an image sensor. The lens assembly according to the exemplary embodiment can be applied to various electronic devices such as a digital camera, an interchangeable lens camera, a video camera, a mobile phone camera, a camera for a small mobile device, a VR, an AR, a drone, or a manned / unmanned aerial vehicle.

[0693] The features, structures, effects, etc. described in the embodiments above are included in at least one embodiment of the present invention, and are not necessarily limited to just one embodiment. Furthermore, the features, structures, effects, etc. exemplified in each embodiment can be combined or modified in other embodiments by those skilled in the art to which the embodiments pertain. Therefore, the contents related to such combinations and modifications should be construed as falling within the scope of the present invention.

[0694] In addition, although the above description focuses on examples, these are merely examples and do not limit the present invention. Those skilled in the art to which the present invention pertains will appreciate that various modifications and applications not exemplified above are possible without departing from the essential characteristics of the present invention. For example, each component specifically shown in the examples can be modified and implemented. In addition, differences related to such modifications and applications should be interpreted as being included within the scope of the present invention defined in the appended claims.

Claims

1. Including first to third lens groups arranged along the optical axis, The above first lens group has positive (+) refractive power, The above second lens group has positive (+) refractive power, The above third lens group has negative (-) refractive power, The above first lens group includes a first lens and a second lens which is a prism lens, The second lens group includes a third lens, a fourth lens, and a fifth lens, The third lens group includes the sixth lens and the seventh lens, The above first lens group and the above second lens group are fixed groups, An optical system including the third lens group as a moving group.

2. In paragraph 1, An optical system in which the first lens has a meniscus shape convex toward the object side on the optical axis.

3. In paragraph 1, The object-side surface of the first lens on the optical axis has a convex shape, An optical system in which the object-side surface of the fourth lens on the optical axis has a convex shape.

4. In paragraph 1, The object-side surface of the third lens on the optical axis has a convex shape, An optical system in which the fourth lens has a meniscus shape convex toward the object side on the optical axis.

5. In paragraph 1, The above first lens is an optical system having positive (+) refractive power.

6. In paragraph 1, The above third lens has positive (+) refractive power, The above fourth lens has a negative (-) refractive power, The above fifth lens is an optical system having positive (+) refractive power.

7. In paragraph 1, The above sixth lens has positive (+) refractive power, The above seventh lens is an optical system having negative (-) refractive power.

8. In paragraph 1, An optical system that satisfies the following conditions. <Conditional expression> 0.1 < LG3_stroke < 1 (In the above conditional expression, LG3 is the stroke length of the third lens group.) 9. In paragraph 1, An optical system that satisfies the following conditions. <Conditional expression> 2 < TTL / ImgH < 5 (In the above conditional expression, TTL is the optical axis distance from the vertex of the object-side surface of the lens placed closest to the object-side of the optical system to the upper surface of the image sensor, and ImgH is the maximum diagonal length of the image sensor.) 10. Including first to seventh lenses arranged along the optical axis, The above first lens has positive (+) refractive power, The above second lens is a prism lens, The above third lens has positive (+) refractive power, The above fourth lens has a negative (-) refractive power, The above fifth lens has positive (+) refractive power, The above sixth lens has positive (+) refractive power, The above seventh lens has a negative (-) refractive power, The above first and second lenses are the first lens group, which is a fixed group, The above third to fifth lenses are the second lens group, which is a fixed group, The above 6th to 7th lenses are the third lens group, which is a moving group, in the optical system.

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