Optical system and camera module

Abstract

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

Description

Optical system and camera module

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

[0002] Camera modules 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 capture the image 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 image quality 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]

[0008] *Camera modules for close-range photography have shorter TTLs than conventional camera modules. For example, camera modules for long-range photography have longer TTLs than conventional camera modules. However, portable devices have limited space for camera modules, making it difficult to incorporate long-range camera modules or camera modules with adjustable image magnification (zoom camera modules). Therefore, a new optical system capable of resolving the aforementioned issues is required.

[0009] The present embodiment seeks to provide an optical system and camera module with improved optical characteristics.

[0010] In addition, it is possible to provide an optical system that can be implemented in a small and compact manner.

[0011] 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.

[0012] Additionally, we aim to provide an optical system applicable to a folded camera or macro mode having a thin thickness or height.

[0013] In order to solve the above technical problem, an optical system according to an embodiment of the present invention includes first to fifth lens groups arranged along an optical axis, wherein the first lens group has positive (+) refractive power, the third lens group has positive (+) refractive power, the fourth lens group has negative (-) refractive power, the second lens group and the fifth lens group include prism lenses, the first lens group and the second lens group move OIS, and the fourth lens group moves AF.

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

[0015] The first lens may have positive (+) refractive power, and the second lens may have negative (-) refractive power.

[0016] The difference between the absolute values ​​of the focal lengths of the first lens and the second lens is 10 or less.

[0017] The second lens group includes a third lens, the third lens group includes a fourth lens and a fifth lens, and the object-side surface of the fourth lens on the optical axis may have a convex shape.

[0018] The fourth lens may have positive (+) refractive power, and the fifth lens may have positive (+) refractive power.

[0019] The fourth lens group may include a sixth lens, a seventh lens, and an eighth lens, wherein the sixth lens may have positive (+) refractive power, the seventh lens may have negative (-) refractive power, and the eighth lens may have negative (-) refractive power.

[0020] In the first lens group, the lens arranged closest to the object side may have a meniscus shape with a convex object side.

[0021] The following condition can be satisfied. <Condition> 1 < LG4_stroke < 3 (In the above condition, LG4 is the stroke length of the fourth lens group.)

[0022] The following condition can be satisfied. <Condition> 1 < TTL / F1 < 1.5 (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 F1 is the focal length of the first lens.)

[0023] In order to solve the above technical problem, an optical system according to an embodiment of the present invention includes first to ninth lenses arranged along an optical axis, wherein the first lens has positive (+) refractive power, the second lens has negative (-) refractive power, the third lens is a prism lens, the fourth lens has positive (+) refractive power, the fifth lens has positive (+) refractive power, the sixth lens has positive (+) refractive power, the seventh lens has negative (-) refractive power, the eighth lens has negative (-) refractive power, and the ninth lens is a prism lens, and the first to third lenses move OIS, and the sixth to eighth lenses move AF.

[0024] The first and second lenses are a first lens group, the third lens is a second lens group, the fourth and fifth lenses are a third lens group, the sixth to eighth lenses are a fourth lens group, the ninth lens is a fifth lens group, and the first lens group may have positive (+) refractive power, the third lens group may have positive (+) refractive power, and the fourth lens group may have negative (-) refractive power.

[0025] The object-side surface of the first lens on the optical axis may have a convex shape.

[0026] The object-side surface of the fourth lens on the optical axis may have a convex shape.

[0027] In the optical axis, the first lens may have a meniscus shape with an object side convex, and in the optical axis, the fourth lens may have a meniscus shape with an object side convex.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] Figure 1 is a configuration diagram of an optical system according to the first embodiment operating in the first mode.

[0033] Figure 2 is a configuration diagram of an optical system according to the first embodiment operating in the second mode.

[0034] Figure 3 is a table showing the aspherical coefficients of lenses in the optical system according to the first embodiment.

[0035] Fig. 4 is a graph showing data on aberration characteristics of an optical system according to the first embodiment operating in the first mode.

[0036] Fig. 5 is a graph showing data on aberration characteristics of an optical system according to the first embodiment operating in the second mode.

[0037] Fig. 6 is a graph showing the relative illumination versus relative field of the optical system according to the first embodiment operating in the first mode.

[0038] Fig. 7 is a graph showing the peripheral light ratio of the optical system according to the first embodiment operating in the second mode.

[0039] Figure 8 is a configuration diagram of an optical system according to the second embodiment operating in the first mode.

[0040] Figure 9 is a configuration diagram of an optical system according to the second embodiment operating in the second mode.

[0041] Fig. 10 is a table showing the aspherical coefficients of lenses in the optical system according to the second embodiment.

[0042] Fig. 11 is a graph showing data on aberration characteristics of an optical system according to the second embodiment operating in the first mode.

[0043] Fig. 12 is a graph showing data on aberration characteristics of an optical system according to the second embodiment operating in the second mode.

[0044] Fig. 13 is a graph showing the relative illumination versus relative field of the optical system according to the second embodiment operating in the first mode.

[0045] Fig. 14 is a graph showing the peripheral light ratio of the optical system according to the second embodiment operating in the second mode.

[0046] Fig. 15 is a configuration diagram of an optical system according to the third embodiment operating in the first mode.

[0047] Fig. 16 is a configuration diagram of an optical system according to the third embodiment operating in the second mode.

[0048] Fig. 17 is a table showing the aspherical coefficients of lenses in the optical system according to the third embodiment.

[0049] Fig. 18 is a graph showing data on aberration characteristics of an optical system according to the third embodiment operating in the first mode.

[0050] Fig. 19 is a graph showing data on aberration characteristics of an optical system according to the third embodiment operating in the second mode.

[0051] Fig. 20 is a graph showing the relative illumination versus relative field of the optical system according to the third embodiment operating in the first mode.

[0052] Fig. 21 is a graph showing the peripheral light ratio of the optical system according to the third embodiment operating in the second mode.

[0053] Fig. 22 is a drawing for explaining the D-cut lens of the present invention.

[0054] Fig. 23 is an example of a portable terminal having an optical system according to the present embodiment.

[0055] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings.

[0056] 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.

[0057] 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.

[0058] Additionally, the terms used in this embodiment are for the purpose of describing the embodiments and are not intended to limit the present invention.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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).

[0065]

[0066] The optical system (1000, 1100, 1200) according to the first to third embodiments may include a plurality of lens groups. In detail, the optical system (1000, 1100, 1200) may include a plurality of lens groups each including at least one lens. For example, the optical system (1000, 1100, 1200) may include a first lens group (LG1), a second lens group (LG2), a third lens group (LG3), a fourth lens group (LG4), and a fifth lens group (LG5) sequentially arranged from the object side toward the image sensor, and an image sensor (400).

[0067] The first to fifth lens groups (LG1, LG2, LG3, LG4, LG5) may each have positive (+) or negative (-) refractive power. The first lens group (LG1) may have positive (+) refractive power. The second lens group (LG2) and the fifth lens group (LG5) may include prism lenses. The third lens group (LG3) may have positive (+) refractive power. In addition, the fourth lens group (LG4) may have negative (-) refractive power.

[0068]

[0069] At least one of the first to fifth lens groups (LG1, LG2, LG3, LG4, LG5) may be provided to be movable in the direction of the optical axis (OA). For example, the fourth lens group (LG4) may be provided to be movable, and the first lens group (LG1), the second lens group (LG2), the third lens group (LG3), and the fifth lens group (LG5) may be fixed. The first lens group (LG1), the second lens group (LG2), the third lens group (LG3), and the fifth lens group (LG5) may be arranged at fixed positions, and the fourth lens group (LG4) may be provided to be movable in the direction of the optical axis (OA).

[0070]

[0071] The first lens group (LG1) may include a plurality of lenses. Specifically, the first lens group (LG1) may include two or more lenses having opposite refractive powers. For example, the first lens group (LG1) may include two lenses. 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 without changing in the operation mode described below. For example, the interval between the first lens (101, 201, 301) and the second lens (102, 202, 302) may be constant without changing in the operation mode described below.

[0072]

[0073] The second lens group (LG2) may include one lens. In detail, the second lens group (LG2) may include a prism lens (103, 203, 303). The optical system (1000, 1100, 1200) may reduce the thickness in the first direction (Y-axis direction) perpendicular to the optical axis (OA) direction (X-axis direction) of the optical system (1000, 1100, 1200) by including the third lens (103, 203, 303) which is a prism lens. When the optical system (1000, 1100, 1200) 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, 1100, 1200).

[0074] 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, 1100, 1200) 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.

[0075] A driving member (not shown) can be connected to a second lens group (LG2) including a prism lens. The driving member can move the first lens group (LG1) and the second lens group (LG2) using the driving force of the actuator. For example, the driving member can tilt-control the first lens group (LG1) and the second lens group (LG2) along the first axis (Y-axis) or the second axis (X-axis). Accordingly, the camera module (1520) can compensate for shaking.

[0076] When the first lens group (LG1) and the second lens group (LG2) are tilt-controlled, the optical path passing through the optical system may change, which may result in a decrease in resolution. To solve this problem, the distance on the optical axis between the prism lens of the second lens group (LG2) and the lens arranged closest to the object side in the third lens group (LG3) may be about 2 mm or less. In addition, the light located at the outermost side among the light emitted from the prism lens of the second lens group (LG2) and incident on the lens arranged closest to the object side in the third lens group (LG3) may be designed to be parallel to the optical axis. In this case, the light located at the outermost side may be light that reaches the center of the image sensor. In order for the light located at the outermost end to be parallel to the optical axis, the absolute value of the focal length of the first lens group (LG1) may be 50 or more and 70 or less, and the signs of the focal lengths of the first lens (101, 201, 301) and the second lens (102, 202, 302) included in the first lens group (LG1) may be different from each other, and the absolute value of the difference in the focal lengths of the two lenses may be 10 or less.

[0077] That is, by setting the gap between the second lens group (LG2) and the third lens group (LG3) small and designing the light path incident from the second lens group (LG2) to the third lens group (LG3) to be parallel to the optical axis, the influence of the optical path tilt due to OIS operation can be reduced, and the deterioration of optical performance can be minimized.

[0078] The actuating member may include at least one actuator. For example, the actuating member may include at least one of a voice coil motor (VCM), a piezoelectric device, a shape memory alloy, and a MEMS device as the actuator.

[0079] 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.

[0080] 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.

[0081] Accordingly, the camera module (1520) according to the first to third embodiments 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.

[0082]

[0083] The third lens group (LG3) may include a plurality of lenses. Specifically, the third lens group (LG3) may include two or more lenses. For example, in the first and third embodiments, the third lens group (LG3) may include two lenses, and in the second embodiment, the third lens group (LG3) may include three lenses. 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 without changing in the operation mode described below. For example, in the first and third embodiments, the interval between the fourth lens (104, 304) and the fifth lens (105, 305) may be constant without changing in the operation mode described below. Additionally, in the second embodiment, the distance between the fourth lens (204) and the fifth lens (205) and the distance between the fifth lens (205) and the sixth lens (206) may be constant and not change depending on the operation mode described later.

[0084] The fourth lens group (LG4) may include a plurality of lenses. Specifically, the fourth lens group (LG4) may include two or more lenses. For example, in the first embodiment, the fourth lens group (LG4) may include three lenses, and in the second and third embodiments, the fourth lens group (LG4) may include two lenses. The plurality of lenses included in the fourth lens group (LG4) may have a set interval. Specifically, the interval between the plurality of lenses included in the fourth lens group (LG4) may be constant and not change in the operation mode described below. For example, in the first embodiment, the distance between the fourth lens (104) and the fifth lens (105) and the distance between the fifth lens (105) and the sixth lens (106) may be constant without changing depending on the operation mode described later, and in the second embodiment, the distance between the seventh lens (207) and the eighth lens (208) and in the third embodiment, the distance between the sixth lens (306) and the seventh lens (307) may be constant without changing depending on the operation mode described later.

[0085] The fourth lens group (LG4) may be a moving group. The fourth lens group (LG4) may be a moving group that moves for AF operation. When the camera module (1520) changes from a mode for photographing an object located at infinity to a mode for photographing an object located at a close distance (macroscopic) (e.g., within 200 mm), the fourth lens group (LG4) may move in a direction closer to the image sensor (400) on the optical axis.

[0086] The fifth lens group (LG5) may include one lens. Specifically, the fifth lens group (LG5) may include a prism lens (109, 209, 308). The description of the prism lens overlaps with the description of the prism lens described in the second lens group (LG2), and is therefore omitted.

[0087]

[0088] That is, the optical system (1000, 1100, 1200) may include a plurality of lens groups (LG1-LG5) and an image sensor (400) sequentially arranged from the object side toward the sensor. Additionally, the optical system (1000, 1100, 1200) may include a plurality of lenses included in lens groups (LG1-LG5), for example, a first lens (101, 201, 301), a second lens (102, 202, 302), a third lens (103, 203, 303), a fourth lens (104, 204, 304), a fifth lens (105, 205, 305), a sixth lens (106, 206, 306), a seventh lens (107, 207, 307), an eighth lens (108, 208, 308), and a ninth lens (109, 209).

[0089] The first lens group (LG1) may include a first lens (101, 201, 301) and a second lens (102, 202, 302). The second lens group (LG2) may include a third lens (103, 203, 303) which is a prism lens. In the first and third embodiments, the third lens group (LG3) may include a fourth lens (104, 304) and a fifth lens (105, 305), and in the second embodiment, the third lens group (LG3) may include fourth to sixth lenses (204, 205, 206).

[0090] In the first embodiment, the fourth lens group (LG4) may include the sixth to eighth lenses (106, 107, 108), and in the second embodiment, the fourth lens group (LG4) may include the seventh lens (207) and the eighth lens (208). In addition, in the third embodiment, the fourth lens group (LG4) may include the sixth lens (306) and the seventh lens (307). In the first to third embodiments, the fifth lens group (LG5) may include the prism lens (109, 209, 308).

[0091]

[0092] Each of the lenses (101-109, 201-209, 301-308) and the image sensor (400) included in the first to third embodiments can be sequentially arranged along the optical axis (OA) of the optical system (1000, 1100, 1200).

[0093] Each of the plurality of lenses (100) may include an effective area and an ineffective area. The effective area may be an area through which light incident on each of the lenses (101-109, 201-209, 301-308) passes. In other words, the effective area may be an area in which the incident light is refracted to implement optical characteristics.

[0094] 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.

[0095] Referring to FIG. 22, among the lenses (101-109, 201-209, 301-308) in the optical systems (1000, 1100, 1200) according to the first to third embodiments, at least one lens may be subjected to the D-cut technique. When the D-cut technique is applied, a portion of the lens effective diameter or rib may be cut to reduce the height of the entire optical system. Here, the height of the entire optical system may mean a length in a direction perpendicular to the optical axis rather than 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.

[0096]

[0097] The image sensor (400) can detect light. The image sensor (400) can detect light that has sequentially passed through a plurality of lenses, for example, each lens (101-109, 201-209, 301-308). The image sensor (400) may include a charge-coupled device (CCD) or a complementary metal oxide semiconductor (CMOS).

[0098] The optical system (1000, 1100, 1200) may further include a filter (500). The filter (500) may be arranged between a plurality of lenses and the image sensor (400). The filter (500) may be arranged between the fifth lens group (LG5) closest to the image sensor (400) among the plurality of lens groups (LG1, LG2, LG3, LG4, LG5) and the image sensor (400). For example, the filter (500) may be arranged between the last lens (109, 209, 308) of the fifth lens group (LG5) closest to the image sensor (400) among the plurality of lenses and the image sensor (400).

[0099] The filter (500) may include at least one optical filter, such as an infrared filter or a cover glass. The filter (500) may allow light of a set wavelength band to pass through and filter out light of a different wavelength band. When the filter (500) includes an infrared filter, it may block radiant heat emitted from external light from being transmitted to the image sensor (400). In addition, the filter (500) may transmit visible light and reflect infrared light.

[0100] The optical system (1000, 1100, 1200) may include an aperture (not shown). The aperture can control the amount of light incident on the optical system (1000, 1100, 1200).

[0101] The aperture may be positioned in front of the first lens (101, 201, 301) or may be positioned between two lenses selected from among the lenses (101-109, 201-209, 301-308). In addition, at least one lens selected from among the lenses (101-109, 201-209, 301-308) may function as an aperture. For example, the object-side or sensor-side of one lens selected from among the lenses (101-109, 201-209, 301-308) may function as an aperture for controlling the amount of light.

[0102]

[0103] The optical system according to the first embodiment of the invention will be described.

[0104] FIG. 1 is a configuration diagram of an optical system according to the first embodiment operating in a first mode, FIG. 2 is a configuration diagram of an optical system according to the first embodiment operating in a second mode, FIG. 3 is a table showing aspherical coefficients of lenses in the optical system according to the first embodiment, FIG. 4 is a graph showing data on aberration characteristics of the optical system according to the first embodiment operating in a first mode, FIG. 5 is a graph showing data on aberration characteristics of the optical system according to the first embodiment operating in a second mode, FIG. 6 is a graph showing a relative illumination versus relative field (REL) of the optical system according to the first embodiment operating in a first mode, and FIG. 7 is a graph showing a relative illumination versus relative field (REL) of the optical system according to the first embodiment operating in a second mode.

[0105] Referring to FIG. 1, the optical system (1000) includes a lens unit, and the lens unit may include first to ninth lenses (101 to 109). The first to ninth lenses (101 to 109) 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 ninth lenses (101 to 109) and a filter (500) and be incident on the image sensor (400).

[0106]

[0107] 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 on the optical axis (OA). The first lens (101) may include a plastic or glass material. For example, the first lens (101) may be provided as a plastic material.

[0108] The first surface (S1) on the object side of the first lens (101) may be convex with respect to the optical axis (OA), and the second surface (S2) on the sensor side may be concave. The first lens (101) may have a meniscus shape that is convex toward the object side. The first lens (101) may have a meniscus shape that is concave toward the sensor side. The first lens (101) may have an aspherical surface. The aspherical coefficients of the first surface (S1) and the second surface (S2) may be provided as L1S1 and L1S1 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.

[0109]

[0110] The second lens (102) may be arranged second from the object side. The second lens (102) may be arranged eighth from the sensor side. The second lens (102) may be arranged between the first lens (101) and the third lens (103). The second lens (102) may have negative (-) refractive power in the optical axis (OA). The second lens (102) may include a plastic or glass material. For example, the second lens (102) may be provided as a plastic material.

[0111] The object-side third surface (S3) of the second lens (102) with respect to the optical axis (OA) may be concave, and the sensor-side fourth surface (S4) may be concave. The second lens (102) may have a concave shape on both sides. The second lens (102) may have an aspherical surface. The aspherical coefficients of the third surface (S3) and the fourth surface (S4) may be provided as L2S1 and L2S1 of FIG. 3. At least one or both of the third surface (S3) and the fourth surface (S4) of the second lens (102) may be provided without a critical point from the optical axis to the end of the effective area.

[0112]

[0113] The third lens (103) may be arranged third from the object side. The third lens (103) may be arranged seventh 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 include a plastic or glass material. For example, the third lens (103) may be provided as a glass material. The fifth surface (S5) on the object side and the sixth surface (S6) on the sensor side of the third lens (103) may be formed as a flat surface.

[0114] The third lens (103) may be a prism lens. The third lens (103) may be a right-angle prism lens. The third lens (103) may be a mirror. The third lens (103) may be a light path control member. The third lens (103) may change the path of light incident from the outside. The third lens (103) may include a reflector and a prism. The third lens (103) may rotate the light path by 90 degrees. The third lens (103) includes an incident surface (S5) on which light is incident, a reflective surface (RS1) that reflects the incident light, and an exit surface (S6) 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 fourth lens (104). The third lens (103) 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).

[0115] In addition, in order to reduce the length in the first axis (Y-axis) direction of the optical system, the angle formed by the reflection surface (RS1) and the exit surface (S6) in the third lens (103) can be changed from about 45 degrees to about 43 degrees or about 47 degrees. The angle formed by the reflection surface (RS1) and the exit surface (S6) in the third lens (103) can be changed to be greater than or less than about 45 degrees depending on the position where the image sensor is placed.

[0116] For example, when the direction of light incident on the lens disposed on the object side of the third lens (103) and the direction of light incident on the image sensor are the same, the angle formed by the reflection surface (RS1) and the exit surface (S6) of the third lens (103) can be changed to about 43 degrees. When the direction of light incident on the lens disposed on the object side of the third lens (103) and the direction of light incident on the image sensor are opposite directions, the angle formed by the reflection surface (RS1) and the exit surface (S6) of the third lens (103) can be changed to about 47 degrees. Through this, the size of the optical system can be reduced within a range that has little effect on the change in the performance of the optical system.

[0117] The fourth lens (104) may be arranged as the fourth lens from the object side. The fourth lens (104) may be arranged as the sixth lens 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 positive 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.

[0118] The seventh surface (S7) on the object side of the fourth lens (104) with respect to the optical axis may be convex, 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 with respect to the optical axis (OA). The fourth lens (104) may have a meniscus shape in which the sensor side is concave with respect to the optical axis (OA). 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.

[0119]

[0120] The fifth lens (105) may be arranged as the fifth lens from the object side. The fifth lens (105) may be arranged as the fifth 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.

[0121] 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. At least one or both of the ninth surface (S9) and the tenth surface (S10) of the fifth lens (105) may be provided without a critical point from the optical axis to the end of the effective area.

[0122]

[0123] The sixth lens (106) may be arranged as the sixth lens from the object side. The sixth lens (106) may be arranged as the fourth 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.

[0124] With respect to the optical axis (OA), the object-side eleventh surface (S11) of the sixth lens (106) may be convex, and the sensor-side twelfth surface (S12) may be convex. The sixth lens (106) may have a convex shape on both sides. The sixth lens (106) 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. 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.

[0125]

[0126] The seventh lens (107) may be arranged as the seventh lens from the object side. The seventh lens (107) may be arranged as the third lens from the sensor side. The seventh lens (107) may be arranged between the sixth lens (106) and the eighth lens (108). 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 as a plastic material.

[0127] With respect to the optical axis (OA), the 13th surface (S13) on the object side of the seventh lens (107) may be convex, and the 14th surface (S14) on the sensor side may be concave. The seventh lens (107) may have a meniscus shape in which the object side is convex. The seventh lens (107) may have a meniscus shape in which the sensor side is concave. The seventh lens (107) 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. 3. At least one or both of the 13th surface (S13) and the 14th surface (S14) of the seventh lens (107) may be provided without a critical point from the optical axis to the end of the effective area.

[0128]

[0129] The eighth lens (108) may be arranged as the eighth lens from the object side. The eighth lens (108) may be arranged as the second lens from the sensor side. The eighth lens (108) may be arranged between the seventh lens (107) and the ninth lens (109). The eighth lens (108) may have negative (-) refractive power. The eighth lens (108) may include a plastic or glass material. For example, the eighth lens (108) may be provided as a plastic material.

[0130] With respect to the optical axis (OA), the 15th surface (S15) on the object side of the 8th lens (108) may be convex, and the 16th surface (S16) on the sensor side may be concave. The 8th lens (108) may have a meniscus shape in which the object side is convex. The 8th lens (108) may have a meniscus shape in which the sensor side is concave. The 8th lens (108) is made of a plastic material and may have an aspherical surface. The aspherical coefficients of the 15th surface (S15) and the 16th surface (S16) may be provided as L8S1 and L8S2 of FIG. 3. At least one or both of the 15th surface (S15) and the 16th surface (S16) of the 8th lens (108) may be provided without a critical point from the optical axis to the end of the effective area.

[0131]

[0132] The ninth lens (109) may be arranged closest to the sensor side. The ninth lens (109) may be arranged farthest from the object side. The ninth lens (109) may be arranged between the eighth lens (108) and the filter (500). The ninth lens (109) may be arranged between the eighth lens (108) and the image sensor (400). The ninth lens (109) may include a plastic or glass material. For example, the ninth lens (109) may be provided as a glass material. The object-side 17th surface (S17) and the sensor-side 18th surface (S18) of the ninth lens (109) may be formed as a flat surface.

[0133] The ninth lens (109) may be a prism lens. The ninth lens (109) may be a right-angle prism lens. The ninth lens (109) may be a mirror. The ninth lens (109) may be a light path control member. The ninth lens (109) may change the path of light incident from the outside. The ninth lens (109) may include a reflector and a prism. The ninth lens (109) may rotate the light path by 90 degrees. The ninth lens (109) includes an incident surface (S17) on which light is incident, a reflective surface (RS2) that reflects the incident light, and an exit surface (S18) that emits the reflected light. The reflective surface (RS2) 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 filter (500). The ninth lens (109) can reflect light incident in the first direction (X-axis direction) and change the path of the light to the second direction (Y-axis direction).

[0134]

[0135] LensSurfaceRadiusThicknessndvdClearAperture1S17.0931.4701.53655.6556.940 S218.6880.703 6.4892S3-43.4280.6101.64023.9016.304 S430.7290.917 5.9703S5Infinity6.520 6.500 S6Infinity0.640 9.3324S79.8391.5001.53655.6555.649 S817.6580.645 5.3295S955.8141.5001.53655.6555.175 S10-10.357 Variable (D1) 4.9606 S11100.0000.4791.64023.9014.000 S12-12.0870.040 4.0127 S1311.6390.4001.57037.5653.995 S148.8480.767 3.9118 S1536.9140.5381.64023.9013.879 S163.957 Variable (D2) 4.1159 S17Infinity4.960 5.618 S18Infinity0.300 6.352 Filter infinity0.210 7.239 infinity0.300 7.307 Image infinity0.000 7.458

[0136] 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.

[0137] In Table 1, the thickness of the third lens (103) and the ninth lens (109), which are prism lenses, may refer to the thickness on the optical axis (OA). For example, the thickness of the third lens (103) may refer to the sum of the thickness from the object side (S5) to the reflective surface (RS1) on the y-axis and the thickness from the reflective surface (RS1) to the sensor side (S6) on the x-axis. In addition, the thickness of the third lens (103) from the object side (S5) to the reflective surface (RS1) on the y-axis and the thickness of the third lens (103) from the reflective surface (RS1) to the sensor side (S6) on the x-axis may be the same. According to a variation, the thickness from the object side (S5) to the reflective surface (RS1) on the y-axis of the third lens (103) and the thickness from the reflective surface (RS1) to the sensor side (S6) on the x-axis of the third lens (103) and the ninth lens (109) may be different.

[0138] Although not listed in Table 1, if the third lens (103) and the ninth lens (109) are prism lenses, they may have different refractive indices and Abbe numbers depending on the material used to make the prism lenses. The third lens (103) and the ninth lens (109) may be mirrors as optical path control elements.

[0139]

[0140] Mode 1 Mode 2 D11.2952.796 D23.5912.090

[0141] 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 either the first or second mode. 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 200 mm) is photographed.

[0142] In the optical system according to the first embodiment, the distance between adjacent lens groups may change during the process of changing from the first mode to the second mode. The first lens group (LG1), the second lens group (LG2), the third lens group (LG3), and the fifth lens group (LG5) are fixed, and only the fourth lens group (LG4) can move. The first lens group (LG1), the second lens group (LG2), the third lens group (LG3), and the fifth lens group (LG5) may be fixed groups, and the fourth lens group (LG4) may be a movable group.

[0143] When operating from the first mode to the second mode, the distance (D1) between the third lens group (LG3) and the fourth lens group (LG4) may increase, and the distance (D2) between the fourth lens group (LG2) and the fifth lens group (LG5) may decrease. When operating from the second mode to the first mode, the distance (D1) between the third lens group (LG3) and the fourth lens group (LG4) may decrease, and the distance (D2) between the fourth lens group (LG2) and the fifth lens group (LG5) may increase.

[0144] The stroke length of the fourth lens group (LG4) can satisfy 1.2 mm to 1.8 mm, and preferably, can satisfy about 1,500 mm. As the fourth lens group (LG4) moves, the optical performance of the optical system (1000) can change. For example, as the fourth lens group (LG4) moves, the angle of view (FOV), EFL (f), Fno, BFL, etc. of the optical system (1000) can change.

[0145]

[0146] EFL(F)19.500EPD6.887BFL_10.810HFOV_110.100BFL_20.810HFOV_210.100TD26.875TD_LG12.783f120.422TD_LG33.645f2-28.018TD_LG42.224f438.852f_LG157.257f516.427f_LG312.336f616.872f_LG4-11.647f7-68.323f_(LG3+LG4)29.761f8-6.967LG4_stroke1.500ET10.808TTL26.875ET20.925ImgH 7.458ET41.181ΣCT17.977ET51.241ΣCG7.598ET60.303CA_Max7.916ET70.389CA_Min3.953ET80.990CA_Aver5.474Fno2.83L_CT_max6.520L_CT_aver1.997L_CT_min0.400

[0147] Table 3 shows the items of the mathematical formulas described above in the optical system (1000) of the first 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 horizontal field of view (HFOV_1 (degree)) in the first mode, the horizontal field of view (HFOV_2 (degree)) in the second mode, the focal lengths (f1 to f9) (mm) of the first to ninth lenses (101 to 109), the edge thicknesses (ET1 to ET9), the lengths of each lens group in the optical axis direction (TD_LG1, TD_LG3, TD_LG4), the focal lengths (f_LG1, f_LG3, f_LG4)(mm), entrance pupil size (EPD (mm)), optical axis distance from the aperture (STOP) to the 18th surface (S18) (SD (mm)), optical axis distance from the first lens (101) to the ninth lens (109) (TD (mm)), brightness (Fno) of the optical system (1000), stroke length (LG4_stroke) of the fourth lens group (LG4), TTL (mm), ImgH (mm), which is the entire optical axis distance of the optical system (1000), maximum effective diameter (CA_Max), minimum effective diameter (CA_Min), average effective diameter (CA_Aver), maximum center thickness (L_CT_max), minimum center thickness (L_CT_min), average center thickness (L_CT_aver) among the first to ninth lenses (101 to 109), etc.

[0148]

[0149] Hereinafter, the center thicknesses of the first to ninth lenses (101 to 109) are represented by CT1 to CT9, the edge thicknesses at the ends of the effective areas of each lens are represented by ET1 to ET9, and the center gap between two adjacent lenses is represented by CG1 to CG8. The back focal length (BFL) is the optical axis distance from the image sensor (400) 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 (400). Hereinafter, some of the descriptions regarding the size relationship between the third lens (103), which is a prism lens, and the ninth lens (109) are omitted.

[0150]

[0151] When comparing the absolute values ​​of the curvature radii of each lens, the curvature radii of the eleventh surface (S11) of the sixth lens (106) on the optical axis (OA) may be the largest among the lenses, and the curvature radii of the sixteenth surface (S16) of the eighth lens (108) 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 third surface (S3) of the second lens (102) may be larger than the absolute value of the curvature radii of the fourth surface (S4). The absolute value of the curvature radii of the seventh surface (S7) of the fourth lens (104) may be smaller 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 greater than the absolute value of the curvature radius of the fourteenth surface (S14). The absolute value of the curvature radius of the fifteenth surface (S15) of the eighth lens (108) may be greater than the absolute value of the curvature radius of the sixteenth surface (S16).

[0152]

[0153] The ratio of the radius of curvature of each lens can satisfy the following conditions.

[0154] Condition 1: 0.1 < |L1R1 / L1R2| < 0.5

[0155] Condition 2: 1 < |L2R1 / L2R2| < 1.5

[0156] Condition 3: 0.5 < |L4R1 / L4R2| < 1

[0157] Condition 4: 5 < |L5R1 / L5R2| < 8

[0158] Condition 5: 7 < |L6R1 / L6R2| < 10

[0159] Condition 6: 1 < |L7R1 / L7R2| < 1.5

[0160] Condition 7: 8 < |L8R1 / L8R2| < 12

[0161]

[0162] When describing the central thickness of the lenses based on the optical axis, the central thicknesses (CT4, CT5) of the fourth lens (104) and the fifth lens (105) are the largest among the lenses, and the central thickness (CT7) of the seventh lens (107) is 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 1 mm or more and 1.3 mm or less.

[0163] The central thickness of each lens may satisfy any one of the following conditions:

[0164] Condition 1: CT4, CT5 > CT1 > CT2, CT6, CT7, CT8

[0165] Condition 2: CT1, CT4, CT5 > CT2 > CT6, CT7, CT8

[0166] Condition 3: CT4 = CT5 > CT1, CT2, CT6, CT7, CT8

[0167] Condition 4: CT1, CT2, CT4, CT5, CT8 > CT6 > CT7

[0168] Condition 5: CT1, CT2, CT4, CT5, CT6, CT8 > CT7

[0169] Condition 6: CT1, CT2, CT4, CT5 > CT8 > CT6, CT7

[0170]

[0171] 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), the distance (CG6) between the sixth lens (106) and the seventh lens (107), and the distance (CG7) between the seventh lens (107) and the eighth lens (108) do not change, but the distance (CG5) between the fifth lens (105) and the sixth lens (106) and the distance (CG8) between the eighth lens (108) and the ninth lens (109) can change. Among the center spacings between the unchanging lenses, the spacing (CG2) between the second lens (102) and the third lens (103) may be the maximum, and the spacing (CG6) between the sixth lens (106) and the seventh lens (107) may be the minimum. The difference between the maximum center spacing and the minimum center spacing among the spaced lens spacings may be 0.5 mm or more, for example, in the range of 0.5 mm to 1 mm.

[0172] The center spacing between each lens can satisfy the conditions below.

[0173] Condition 1: CG2, CG7 > CG1 > CG3, CG4, CG6

[0174] Condition 2: CG2 > CG1, CG3, CG4, CG6, CG7

[0175] Condition 3: CG1, CG2, CG4, CG7 > CG3 > CG6

[0176] Condition 4: CG1, CG2, CG7 > CG4 > CG3, CG6

[0177] Condition 5: CG1, CG2, CG3, CG4, CG7 > CG6

[0178] Condition 6: CG2 > CG7 > CG1, CG3, CG4, CG6

[0179]

[0180] In terms of 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 on the object side and the sensor side of each lens. The lens surface having the maximum effective diameter may be the sixth surface (S6) of the third lens (103). The lens having the minimum effective diameter may be the eighth lens (108). The lens surface having the minimum effective diameter may be the seventeenth surface (S17) of the eighth lens (108).

[0181] The effective diameter of each lens can satisfy any one of the conditions below.

[0182] Condition 1: CA_L1 > CA_L2, CA_L4, CA_L5, CA_L6, CA_L7, CA_L8

[0183] Condition 2: CA_L1 > CA_L2 > CA_L4, CA_L5, CA_L6, CA_L7, CA_L8

[0184] Condition 3: CA_L1, CA_L2 > CA_L4 > CA_L5, CA_L6, CA_L7, CA_L8

[0185] Condition 4: CA_L1, CA_L2, CA_L4 > CA_L5 > CA_L6, CA_L7, CA_L8

[0186] Condition 5: CA_L1, CA_L2, CA_L4, CA_L5 > CA_L6 > CA_L7, CA_L8

[0187] Condition 6: CA_L1, CA_L2, CA_L4, CA_L5, CA_L6, CA_L8 > CA_L7

[0188] Condition 7: CA_L1, CA_L2, CA_L4, CA_L5, CA_L6 > CA_L8 > CA_L7

[0189]

[0190] Regarding the refractive index, the refractive index of the second lens (102), the sixth lens (106), and the eighth lens (108) may be the largest among the lenses and may be greater than 1.6, for example, greater than 1.62. One or all of the first lens (101), the fourth lens (104), and the fifth lens (105) may have the smallest refractive index among the lenses. For example, the refractive index of the first lens (101), the fourth lens (104), and the fifth lens (105) may be the smallest among the lenses and may be less than 1.6, for example, less than 1.55. The difference between the maximum refractive index and the minimum refractive index may be 0.1 or more.

[0191] The refractive index of each lens can satisfy any of the conditions below.

[0192] Condition 1: n2, n6, n7, n8 > n1 = n4 = n5

[0193] Condition 2: n2 = n6 = n8 > n1, n4, n5, n7

[0194] Condition 3: n2, n6, n8 > n7 > n1, n4, n5

[0195]

[0196] Comparing the Abbe numbers, the Abbe number of any one of the first lens (101), the fourth lens (104), and the fifth lens (105) is the largest among the lenses and may be 50 or more. The Abbe numbers of the second lens (102), the sixth lens (106), and the eighth lens (108) are the smallest among the lenses and may be 30 or less. The difference between the maximum refractive index and the minimum Abbe number may be 30 or more.

[0197] The Abbe number of each lens can satisfy any of the conditions below.

[0198] Condition 1: v1 = v4 = v5 > v2, v6, v7, v8

[0199] Condition 2: v1, v4, v5, v7 > v2 = v6 = v8

[0200] Condition 3: v1, v4, v5 > v7 > v2, v6, v8

[0201]

[0202] The focal lengths (F1, F4, F5, F6) of the first, fourth, fifth, and sixth lenses (101, 104, 105, and 106) may have positive (+) signs. The first, fourth, fifth, and sixth lenses (101, 104, 105, and 106) may have positive (+) refractive power. The focal lengths (F2, F7, F8) of the second, seventh, and eighth lenses (102, 107, and 108) may have negative (-) signs. The second, seventh, and eighth lenses (102, 107, and 108) may have negative (-) refractive power.

[0203] When comparing the focal lengths in absolute values, the focal length of the seventh lens (107) is the largest among the lenses, and may be 50 or more and 80 or less. The focal length of the eighth lens (108) is the smallest among the lenses, and the absolute value of the focal length of the eighth lens (108) may be 5 or more and 8 or less.

[0204] The absolute value of the focal length of each lens can satisfy any of the conditions below.

[0205] Condition 1: |f2|, |f4|, |f7| > |f1| > |f5|, |f6|, |f8|

[0206] Condition 2: |f4|, |f7| > |f2| > |f1|, |f5|, |f6|, |f8|

[0207] Condition 3: |f7| > |f4| > |f1|, |f2|, |f5|, |f6|, |f8|

[0208] Condition 4: |f1|, |f2|, |f4|, |f6|, |f7| > |f5| > |f8|

[0209] Condition 5: |f1|, |f2|, |f4|, |f7| > |f6| > |f5|, |f8|

[0210] Condition 6: |f7| > |f1|, |f2|, |f4|, |f5|, |f6|, |f8|

[0211] Condition 7: |f1|, |f2|, |f4|, |f5|, |f6|, |f7| > |f8|

[0212]

[0213] 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_LG3) of the third lens group (LG3) can have a positive (+) sign. The third lens group (LG3) can have a positive (+) composite refractive power. The composite focal length (f_LG4) of the fourth lens group (LG4) can have a negative (-) sign. The fourth lens group (LG4) 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.

[0214] When comparing the absolute values ​​of the composite focal lengths of the first lens group (LG1), the third lens group (LG3), and the fourth lens group (LG4), the composite focal length of the first lens group (LG1) may be the largest, and the composite focal length of the fourth lens group (LG4) may be the smallest. The relationship between the composite focal lengths of the first lens group (LG1), the third lens group (LG3), and the fourth lens group (LG4) may satisfy |f_LG1| > |f_LG3| > |f_LG4|.

[0215]

[0216] The thickness (CT1) of the first lens (101) may be a difference of 1 or more times, for example, 1.5 to 2 times, between the maximum thickness and the minimum thickness, and the center thickness (CT1) may be maximum and the edge thickness (ET1) may be minimum. The thickness (T2) of the second lens (102) may be minimum at the center and maximum at the edge, and the maximum thickness is in the range of 1.5 to 2 times the minimum thickness. The thickness (T4) of the fourth lens (104) 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 (T5) of the fifth lens (105) 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 (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 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 (T8) of the eighth lens (108) may be minimum at the center and maximum at the edge, and the maximum thickness is in the range of 1.5 to 2 times the minimum thickness.

[0217]

[0218] The thickness of each lens can satisfy any of the conditions below.

[0219] Condition 1: 1.5 < CT1 / ET1 < 2, 0.5 < ET1 / CT1 < 1

[0220] Condition 2: 0.5 < CT2 / ET2 < 1, 1.5 < ET2 / CT2 < 2

[0221] Condition 3: 1 < CT4 / ET4 < 1.5, 0.5 < ET4 / CT4 < 1

[0222] Condition 4: 1 < CT5 / ET5 < 1.5, 0.5 < ET5 / CT5 < 1

[0223] Condition 5: 1.5 < CT6 / ET6 < 2, 0.5 < ET6 / CT6 < 1

[0224] Condition 6: 1 < CT7 / ET7 < 1.5, 0.5 < ET7 / CT7 < 1

[0225] Condition 7: 0.5 < CT8 / ET8 < 1, 1.5 < ET8 / CT8 < 2

[0226] Condition 8: 1 < ΣCT / ΣET < 1.5, 0.5 < ΣET / ΣCT < 1

[0227]

[0228] Among the gaps (G1-G7) between the lenses, the gap (LG1) between the first and second lenses (101, 102) may have a maximum in the center and a minimum in the edge. The gap (LG2) between the second and third lenses (102, 103) may have a minimum in the edge and a maximum in the center. The gap (LG3) between the third and fourth lenses (103, 104) may have a maximum in the edge and a minimum in the center. The gap (G4) between the fourth and fifth lenses (104, 105) may have a minimum in the edge and a maximum in the center. The fifth gap (G5) between the fifth and sixth lenses (105, 106) may have a minimum in the center and a maximum in the edge. The sixth gap (G6) between the sixth and seventh lenses (106, 107) may have a minimum in the center and a maximum in the edge. The seventh gap (G7) between the seventh and eighth lenses (107, 108) may be maximum at the center and minimum at the edge. The eighth gap (G8) between the eighth and ninth lenses (108, 109) may be maximum at the center and minimum at the edge.

[0229]

[0230] FIG. 4 is a graph showing the aberration characteristics of the optical system in the first mode according to the first embodiment, and FIG. 5 is a graph showing the aberration characteristics of the optical system in the second mode according to the first embodiment. In the aberration graphs of FIGS. 4 and 5, spherical aberration (longitudinal spherical aberration), astigmatic field curves, and distortion are measured from left to right. In FIGS. 4 and 5, the X-axis may represent a focal length (mm) and a degree of distortion (%), and the Y-axis may represent the height of the image. In addition, the graph for spherical aberration is a graph for light in wavelength bands of about 435 nm, about 470 nm, about 510 nm, about 555 nm, about 610 nm, and 650 nm, and the graphs for astigmatism and distortion are graphs for light in wavelength bands of about 555 nm. In the aberration diagrams of FIGS. 4 and 5, 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.

[0231]

[0232] Fig. 6 is a graph showing the relative illumination versus relative field (RI) of the optical system according to the first embodiment operating in the first mode, and Fig. 7 is a graph showing the relative illumination of the optical system according to the first embodiment operating in the second mode. Figs. 6 and 7 are graphs showing the relative illumination (RI) from the center of the image sensor in the optical system to the image height (MaxF = 1F), that is, from 0 to the maximum height. It can be seen that the relative illumination of 20% or more, for example, more than 30%, is shown from the center of the image sensor to the diagonal end (1.0F). That is, it can be seen that the difference in the peripheral illumination in the first mode and the second mode of the first embodiment is almost the same from the optical axis to the end of the effective area. Accordingly, since the minimum light quantity from the center to the edge of the image sensor is exceeded by 30%, more accurate sensing values ​​can be obtained across the entire area of ​​the image sensor.

[0233]

[0234] An optical system according to the second embodiment of the present invention will be described.

[0235] FIG. 8 is a configuration diagram of an optical system according to the second embodiment operating in the first mode, FIG. 9 is a configuration diagram of an optical system according to the second embodiment operating in the second mode, FIG. 10 is a table showing aspherical coefficients of lenses in the optical system according to the second embodiment, FIG. 11 is a graph showing data on aberration characteristics of the optical system according to the second embodiment operating in the first mode, FIG. 12 is a graph showing data on aberration characteristics of the optical system according to the second embodiment operating in the second mode, FIG. 13 is a graph showing a relative illumination versus relative field (Relative Illumination Versus Relative Field) of the optical system according to the second embodiment operating in the first mode, and FIG. 14 is a graph showing a peripheral illumination ratio of the optical system according to the second embodiment operating in the second mode.

[0236] Referring to FIG. 8, the optical system (1100) includes a lens unit, and the lens unit may include first to ninth lenses (201 to 209). The first to ninth lenses (201 to 209) 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 ninth lenses (201 to 209) and the filter (500) and be incident on the image sensor (400).

[0237]

[0238] 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 on the optical axis (OA). The first lens (201) may include a plastic or glass material. For example, the first lens (201) may be provided as a plastic material.

[0239] The first surface (S1) on the object side of the first lens (201) may be convex with respect to the optical axis (OA), and the second surface (S2) on the sensor side may be concave. The first lens (201) may have a meniscus shape that is convex toward the object side. The first lens (201) may have a meniscus shape that is concave toward the sensor side. The first lens (201) may have an aspherical surface. The aspherical coefficients of the first surface (S1) and the second surface (S2) may be provided as L1S1 and L1S1 of FIG. 10. 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.

[0240]

[0241] The second lens (202) may be arranged second from the object side. The second lens (202) may be arranged eighth from the sensor side. The second lens (202) may be arranged between the first lens (201) and the third lens (203). The second lens (202) may have negative refractive power in the optical axis (OA). The second lens (202) may include a plastic or glass material. For example, the second lens (202) may be provided as a plastic material.

[0242] The object-side third surface (S3) of the second lens (202) with respect to the optical axis (OA) may be concave, and the sensor-side fourth surface (S4) may be concave. The second lens (202) may have a concave shape on both sides. The second lens (202) may have an aspherical surface. The aspherical coefficients of the third surface (S3) and the fourth surface (S4) may be provided as L2S1 and L2S1 of FIG. 10. At least one or both of the third surface (S3) and the fourth surface (S4) of the second lens (202) may be provided without a critical point from the optical axis to the end of the effective area.

[0243]

[0244] The third lens (203) may be arranged third from the object side. The third lens (203) may be arranged seventh 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 include a plastic or glass material. For example, the third lens (203) may be provided as a glass material. The fifth surface (S5) on the object side and the sixth surface (S6) on the sensor side of the third lens (203) may be formed as a flat surface.

[0245] The third lens (203) may be a prism lens. The third lens (203) may be a right-angle prism lens. The third lens (203) may be a mirror. The third lens (203) may be a light path control member. The third lens (203) may change the path of light incident from the outside. The third lens (203) may include a reflector and a prism. The third lens (203) may rotate the light path by 90 degrees. The third lens (203) includes an incident surface (S5) on which light is incident, a reflective surface (RS1) that reflects the incident light, and an exit surface (S6) 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 fourth lens (204). The third lens (203) 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).

[0246] In addition, in order to reduce the length in the first axis (Y-axis) direction of the optical system, the angle formed by the reflection surface (RS1) and the exit surface (S6) in the third lens (203) may be changed from about 45 degrees to about 43 degrees or about 47 degrees. The angle formed by the reflection surface (RS1) and the exit surface (S6) in the third lens (203) may be changed to be greater than or less than about 45 degrees depending on the position where the image sensor is placed.

[0247] For example, when the direction of light incident on the lens disposed on the object side of the third lens (203) and the direction of light incident on the image sensor are the same, the angle formed by the reflection surface (RS1) and the exit surface (S6) of the third lens (203) can be changed to about 43 degrees. When the direction of light incident on the lens disposed on the object side of the third lens (203) and the direction of light incident on the image sensor are opposite directions, the angle formed by the reflection surface (RS1) and the exit surface (S6) of the third lens (203) can be changed to about 47 degrees. Through this, the size of the optical system can be reduced within a range that has little effect on the change in the performance of the optical system.

[0248] The fourth lens (204) may be arranged as the fourth lens from the object side. The fourth lens (204) may be arranged as the sixth lens 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 positive 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.

[0249] The seventh surface (S7) on the object side of the fourth lens (204) with respect to the optical axis may be convex, and the eighth surface (S8) on the sensor side may be convex. The fourth lens (204) may have a shape in which both sides are convex. 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. 10. 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.

[0250]

[0251] The fifth lens (205) may be arranged as the fifth lens from the object side. The fifth lens (205) may be arranged as the fifth 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.

[0252] 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. 10. At least one or both of the ninth surface (S9) and the tenth surface (S10) of the fifth lens (205) may be provided without a critical point from the optical axis to the end of the effective area.

[0253]

[0254] The sixth lens (206) may be arranged as the sixth lens from the object side. The sixth lens (206) may be arranged as the fourth 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 negative (-) 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.

[0255] With respect to the optical axis (OA), the object-side eleventh surface (S11) of the sixth lens (206) may be concave, and the sensor-side twelfth surface (S12) may be concave. The sixth lens (206) may have a concave shape on both sides. The sixth lens (206) 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. 10. 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.

[0256]

[0257] The seventh lens (207) may be arranged as the seventh lens from the object side. The seventh lens (207) may be arranged as the third lens from the sensor side. The seventh lens (207) may be arranged between the sixth lens (206) and the eighth lens (208). 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 as a plastic material.

[0258] 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 convex. The seventh lens (207) may have a meniscus shape in which the object side is concave. The seventh lens (207) may have a meniscus shape in which the sensor side is convex. The seventh lens (207) 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. 10. At least one or both of the 13th surface (S13) and the 14th surface (S14) of the seventh lens (207) may be provided without a critical point from the optical axis to the end of the effective area.

[0259]

[0260] The eighth lens (208) may be arranged as the eighth lens from the object side. The eighth lens (208) may be arranged as the second lens from the sensor side. The eighth lens (208) may be arranged between the seventh lens (207) and the ninth lens (209). The eighth lens (208) may have negative (-) refractive power. The eighth lens (208) may include a plastic or glass material. For example, the eighth lens (208) may be provided as a plastic material.

[0261] With respect to the optical axis (OA), the 15th surface (S15) on the object side of the 8th lens (208) may be convex, and the 16th surface (S16) on the sensor side may be concave. The 8th lens (208) may have a meniscus shape in which the object side is convex. The 8th lens (208) may have a meniscus shape in which the sensor side is concave. The 8th lens (208) is made of a plastic material and may have an aspherical surface. The aspherical coefficients of the 15th surface (S15) and the 16th surface (S16) may be provided as L8S1 and L8S2 of FIG. 10. At least one or both of the 15th surface (S15) and the 16th surface (S16) of the 8th lens (208) may be provided without a critical point from the optical axis to the end of the effective area.

[0262]

[0263] The ninth lens (209) may be arranged closest to the sensor side. The ninth lens (209) may be arranged farthest from the object side. The ninth lens (209) may be arranged between the eighth lens (208) and the filter (500). The ninth lens (209) may be arranged between the eighth lens (208) and the image sensor (400). The ninth lens (209) may include a plastic or glass material. For example, the ninth lens (209) may be provided as a glass material. The object-side 17th surface (S17) and the sensor-side 18th surface (S18) of the ninth lens (209) may be formed as a flat surface.

[0264] The ninth lens (209) may be a prism lens. The ninth lens (209) may be a right-angle prism lens. The ninth lens (209) may be a mirror. The ninth lens (209) may be a light path control member. The ninth lens (209) may change the path of light incident from the outside. The ninth lens (209) may include a reflector and a prism. The ninth lens (209) may rotate the light path by 90 degrees. The ninth lens (209) includes an incident surface (S17) on which light is incident, a reflective surface (RS2) that reflects the incident light, and an exit surface (S18) that emits the reflected light. The reflective surface (RS2) 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 filter (500). The ninth lens (209) can reflect light incident in the first direction (X-axis direction) and change the path of the light to the second direction (Y-axis direction).

[0265]

[0266] LensSurfaceRadiusThicknessndvdClearAperture1S17.3641.4701.53952.3976.940 S229.5650.703 6.6182S3-21.4250.6101.57535.7336.352 S428.4130.917 5.9833S5Infinity6.520 6.500 S6Infinity0.640 9.3324S76.9961.4961.54251.2105.834 S8-29.6890.057 5.5555S925.9771.5001.53655.6995.205 S10-4.7520.141 4.6416S11-6.0110.4171.57732.3064.440 S126.825Variable(D1) 4.2407S13-4.0580.7551.55842.0994.809 S14-8.8040.118 4.8268S154.4480.7731.67819.2304.857 S165.123Variable(D2) 5.2679S17Infinity4.960 5.924 S18Infinity0.300 6.378Filter infinity0.210 6.923 infinity0.300 6.965Image infinity0.000 7.057

[0267] 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.

[0268] In Table 4, the thickness of the third lens (203) and the ninth lens (209), which are prism lenses, may refer to the thickness on the optical axis (OA). For example, the thickness of the third lens (203) may refer to the sum of the thickness from the object side (S5) to the reflective surface (RS1) on the y-axis and the thickness from the reflective surface (RS1) to the sensor side (S6) on the x-axis. In addition, the thickness of the third lens (203) from the object side (S5) to the reflective surface (RS1) on the y-axis and the thickness of the third lens (203) from the reflective surface (RS1) to the sensor side (S6) on the x-axis may be the same. According to a variation, the thickness from the object side (S5) to the reflective surface (RS1) on the y-axis of the third lens (203) and the thickness from the reflective surface (RS1) to the sensor side (S6) on the x-axis of the third lens (203) and the ninth lens (209) may be different.

[0269] Although not listed in Table 4, if the third lens (203) and the ninth lens (209) are prism lenses, they may have different refractive indices and Abbe numbers depending on the material from which the prism lenses are made. The third lens (203) and the ninth lens (209) may be mirrors as optical path control members.

[0270]

[0271] Mode 1 Mode 2 D11.5574.185 D24.0141.387

[0272] 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 either the first or second mode. 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 200 mm) is photographed.

[0273] In the optical system according to the second embodiment, the distance between adjacent lens groups may change during the process of changing from the first mode to the second mode. The first lens group (LG1), the second lens group (LG2), the third lens group (LG3), and the fifth lens group (LG5) are fixed, and only the fourth lens group (LG4) can move. The first lens group (LG1), the second lens group (LG2), the third lens group (LG3), and the fifth lens group (LG5) may be fixed groups, and the fourth lens group (LG4) may be a movable group.

[0274] When operating from the first mode to the second mode, the distance (D1) between the third lens group (LG3) and the fourth lens group (LG4) may increase, and the distance (D2) between the fourth lens group (LG2) and the fifth lens group (LG5) may decrease. When operating from the second mode to the first mode, the distance (D1) between the third lens group (LG3) and the fourth lens group (LG4) may decrease, and the distance (D2) between the fourth lens group (LG2) and the fifth lens group (LG5) may increase.

[0275] The stroke length of the fourth lens group (LG4) can satisfy 2.5 mm to 3 mm, and preferably, can satisfy about 2.627 mm. As the fourth lens group (LG4) moves, the optical performance of the optical system (1100) can change. For example, as the fourth lens group (LG4) moves, the angle of view (FOV), EFL (f), Fno, BFL, etc. of the optical system (1100) can change.

[0276]

[0277] EFL(F)19.500EPD6.940BFL_10.810HFOV_110.100BFL_20.810HFOV_210.100TD26.950TD_LG12.783f117.779TD_LG33.053f2-21.160TD_LG43.621f410.606f_LG168.494f57.628f_LG315.010f6-5.478f_LG4-23.495f7-14.312f_(LG3+LG4)24.990f834.051LG4_stroke2.627ET10.672TTL24.170ET21.135ImgH 7.057ET40.736ΣCT18.502ET50.870ΣCG8.148ET61.071CA_Max7.916ET70.994CA_Min4.340ET80.695CA_Aver5.761Fno2.809L_CT_max6.520L_CT_aver2.056L_CT_min0.417

[0278] Table 6 shows the items of the mathematical formulas described above in the optical system (1100) of the second 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 horizontal field of view (HFOV_1 (degree)) in the first mode, the horizontal field of view (HFOV_2 (degree)) in the second mode, the focal lengths (f1 to f9) (mm) of the first to ninth lenses (201 to 209), the edge thicknesses (ET1 to ET9), the lengths of each lens group in the optical axis direction (TD_LG1, TD_LG3, TD_LG4), the focal lengths (f_LG1, f_LG3, f_LG4)(mm), the size of the entrance pupil (EPD (mm)), the optical axis distance from the aperture (STOP) to the 18th surface (S18) (SD (mm)), the optical axis distance from the first lens (201) to the ninth lens (209) (TD (mm)), the brightness (Fno) of the optical system (1100), the stroke length (LG4_stroke) of the fourth lens group (LG4), 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 ninth lenses (201 to 209), etc.

[0279]

[0280] Hereinafter, the center thicknesses of the first to ninth lenses (201 to 209) are represented by CT1 to CT9, the edge thicknesses at the ends of the effective areas of each lens are represented by ET1 to ET9, and the center gap between two adjacent lenses is represented by CG1 to CG8. The BFL (Back focal length) is the optical axis distance from the image sensor (400) 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 (400). Hereinafter, some of the descriptions regarding the size relationship between the third lens (203), which is a prism lens, and the ninth lens (209) are omitted.

[0281]

[0282] When comparing the absolute values ​​of the curvature radii of each lens, the curvature radii of the eighth surface (S8) of the fourth lens (204) on the optical axis (OA) may be the largest among the lenses, and the curvature radii of the thirteenth surface (S13) of the seventh lens (207) 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 third surface (S3) of the second lens (202) may be smaller than the absolute value of the curvature radii of the fourth surface (S4). The absolute value of the curvature radii of the seventh surface (S7) of the fourth lens (204) may be smaller 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 less 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 less than the absolute value of the curvature radius of the fourteenth surface (S14). The absolute value of the curvature radius of the fifteenth surface (S15) of the eighth lens (208) may be less than the absolute value of the curvature radius of the sixteenth surface (S16).

[0283]

[0284] The ratio of the radius of curvature of each lens can satisfy the following conditions.

[0285] Condition 1: 0.1 < |L1R1 / L1R2| < 0.5

[0286] Condition 2: 0.5 < |L2R1 / L2R2| < 1

[0287] Condition 3: 0.1 < |L4R1 / L4R2| < 0.5

[0288] Condition 4: 5 < |L5R1 / L5R2| < 8

[0289] Condition 5: 0.5 < |L6R1 / L6R2| < 1

[0290] Condition 6: 0.1 < |L7R1 / L7R2| < 0.5

[0291] Condition 7: 0.5 < |L8R1 / L8R2| < 1

[0292]

[0293] When describing the central thickness of the lenses based on the optical axis, the central thickness (CT5) of the fifth lens (205) is the largest among the lenses, and the central thickness (CT6) of the sixth lens (206) is the smallest among the lenses. The difference between the maximum and minimum central thicknesses among the lenses may be in the range of 1 mm or more and 1.3 mm or less.

[0294] The central thickness of each lens may satisfy any one of the following conditions:

[0295] Condition 1: CT4, CT5 > CT1 > CT2, CT6, CT7, CT8

[0296] Condition 2: CT1, CT4, CT5, CT7, CT8 > CT2 > CT6

[0297] Condition 3: CT5 > CT4 > CT1, CT2, CT6, CT7, CT8

[0298] Condition 4: CT5 > CT1, CT2, CT4, CT6, CT7, CT8

[0299] Condition 5: CT1, CT2, CT4, CT5, CT7, CT8 > CT6

[0300] Condition 6: CT1, CT4, CT5, CT8 > CT7 > CT2, CT6

[0301] Condition 7: CT1, CT4, CT5 > CT8 > CT2, CT6, CT7

[0302]

[0303] 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), the distance (CG5) between the fifth lens (205) and the sixth lens (206), and the distance (CG7) between the seventh lens (207) and the eighth lens (208) do not change, but the distance (CG6) between the sixth lens (206) and the seventh lens (207) and the distance (CG8) between the eighth lens (208) and the ninth lens (209) can change. Among the center spacings between the unchanging lenses, the spacing (CG2) between the second lens (202) and the third lens (203) may be the maximum, and the spacing (CG4) between the fourth lens (204) and the fifth lens (205) may be the minimum. The difference between the maximum center spacing and the minimum center spacing among the spaced lens spacings may be 0.5 mm or more, for example, in the range of 0.5 mm to 1 mm.

[0304] The center spacing between each lens can satisfy the conditions below.

[0305] Condition 1: CG2 > CG1 > CG3, CG4, CG5, CG7

[0306] Condition 2: CG2 > CG1, CG3, CG4, CG5, CG7

[0307] Condition 3: CG1, CG2 > CG3 > CG4, CG5, CG7

[0308] Condition 4: CG1, CG2, CG3, CG5, CG7 > CG4

[0309] Condition 5: CG1, CG2, CG3 > CG5 > CG4, CG7

[0310] Condition 6: CG1, CG2, CG3, CG5 > CG7 > CG4

[0311]

[0312] In terms of 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 on the object side and the sensor side of each lens. The lens surface having the maximum effective diameter may be the sixth surface (S6) of the third lens (203). The lens having the minimum effective diameter may be the sixth lens (206). The lens surface having the minimum effective diameter may be the twelfth surface (S12) of the sixth lens (206).

[0313] The effective diameter of each lens can satisfy any one of the conditions below.

[0314] Condition 1: CA_L1 > CA_L2, CA_L4, CA_L5, CA_L6, CA_L7, CA_L8

[0315] Condition 2: CA_L1 > CA_L2 > CA_L4, CA_L5, CA_L6, CA_L7, CA_L8

[0316] Condition 3: CA_L1, CA_L2 > CA_L4 > CA_L5, CA_L6, CA_L7, CA_L8

[0317] Condition 4: CA_L1, CA_L2, CA_L4, CA_L8 > CA_L5 > CA_L6, CA_L7

[0318] Condition 5: CA_L1, CA_L2, CA_L4, CA_L5, CA_L7, CA_L8 > CA_L6

[0319] Condition 6: CA_L1, CA_L2, CA_L4, CA_L5, CA_L8 > CA_L7 > CA_L6

[0320] Condition 7: CA_L1, CA_L2, CA_L4 > CA_L8 > CA_L5, CA_L6, CA_L7

[0321]

[0322] Regarding the refractive index, the refractive index of the eighth lens (208) may be the highest among the lenses and may be greater than 1.6, for example, greater than 1.65. The fifth lens (205) may have the lowest refractive index among the lenses. For example, the refractive index of the fifth lens (205) may be the lowest among the lenses and may be less than 1.6, for example, less than 1.55. The difference between the maximum refractive index and the minimum refractive index may be 0.1 or more.

[0323] The refractive index of each lens can satisfy any of the conditions below.

[0324] Condition 1: n2, n4, n6, n7, n8 > n1 > n5

[0325] Condition 2: n6, n8 > n2 > n1, n4, n5, n7

[0326] Condition 3: n2, n6, n7, n8 > n4 > n1, n5

[0327] Condition 4: n1, n2, n4, n6, n7, n8 > n5

[0328] Condition 5: n8 > n6 > n1, n2, n4, n5, n7

[0329] Condition 6: n2, n6, n8 > n7 > n1, n4, n5

[0330] Condition 7: n8 > n1, n2, n4, n5, n6, n7

[0331]

[0332] Comparing the Abbe numbers, the Abbe number of the fifth lens (205) is the largest among the lenses and may be 50 or more. The Abbe number of the eighth lens (208) is 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.

[0333] The Abbe number of each lens can satisfy any of the conditions below.

[0334] Condition 1: v5 > v1 > v2, v4, v6, v7, v8

[0335] Condition 2: v1, v4, v5, v7 > v2 > v6, v8

[0336] Condition 3: v1, v5 > v4 > v2, v6, v7, v8

[0337] Condition 4: v5 > v1, v2, v4, v6, v7, v8

[0338] Condition 5: v1, v2, v4, v5, v7 > v6 > v8

[0339] Condition 6: v1, v4, v5 > v7 > v2, v6, v8

[0340] Condition 7: v1, v2, v4, v5, v6, v7 > v8

[0341]

[0342] The focal lengths (F1, F4, F5, F8) of the 1st, 4th, 5th, and 8th lenses (201, 204, 205, and 208) can have positive (+) signs. The 1st, 4th, 5th, and 8th lenses (201, 204, 205, and 208) can have positive (+) refractive power. The focal lengths (F2, F6, F7) of the 2nd, 6th, and 7th lenses (202, 206, and 207) can have negative (-) signs. The 2nd, 6th, and 7th lenses (202, 206, and 207) can have negative (-) refractive power.

[0343] When comparing the focal lengths in absolute values, the focal length of the eighth lens (208) is the largest among the lenses, and may be 30 or more and 50 or less. The focal length of the sixth lens (206) is the smallest among the lenses, and the absolute value of the focal length of the sixth lens (206) may be 5 or more and 8 or less.

[0344] The absolute value of the focal length of each lens can satisfy any of the conditions below.

[0345] Condition 1: |f2|, |f8| > |f1| > |f4|, |f5|, |f6|, |f7|

[0346] Condition 2: |f8| > |f2| > |f1|, |f4|, |f5|, |f6|, |f7|

[0347] Condition 3: |f1|, |f2|, |f7|, |f8| > |f4| > |f5|, |f6|

[0348] Condition 4: |f1|, |f2|, |f4|, |f7|, |f8| > |f5| > |f6|

[0349] Condition 5: |f1|, |f2|, |f4|, |f5|, |f7|, |f8| > |f6|

[0350] Condition 6: |f1|, |f2|, |f8| > |f7| > |f4|, |f5|, |f6|

[0351] Condition 7: |f8| > |f1|, |f2|, |f4|, |f5|, |f6|, |f7|

[0352]

[0353] 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_LG3) of the third lens group (LG3) can have a positive (+) sign. The third lens group (LG3) can have a positive (+) composite refractive power. The composite focal length (f_LG4) of the fourth lens group (LG4) can have a negative (-) sign. The fourth lens group (LG4) 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.

[0354] When comparing the absolute values ​​of the composite focal lengths of the first lens group (LG1), the third lens group (LG3), and the fourth lens group (LG4), 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 lens group (LG1), the third lens group (LG3), and the fourth lens group (LG4) may satisfy |f_LG1| > |f_LG4| > |f_LG3|.

[0355]

[0356] The thickness (CT1) of the first lens (201) may be a difference of at least twice the maximum thickness and the minimum thickness, for example, in a range of 2 to 2.5 times, and the center thickness (CT1) may be maximum and the edge thickness (ET1) may be minimum. The thickness (T2) of the second lens (202) may be minimum at the center and maximum at the edge, and the maximum thickness is in a range of 1.5 to 2 times the minimum thickness. The thickness (T4) of the fourth lens (204) may be maximum at the center and minimum at the edge, and the maximum thickness is in a range of 2 to 2.5 times the minimum thickness. The thickness (T5) of the fifth lens (205) may be maximum at the center and minimum at the edge, and the maximum thickness is in a range of 1.5 to 2 times the minimum thickness. The thickness (T6) of the sixth lens (206) may be minimum at the center and maximum at the edge, and the maximum thickness is in the range of 2.5 to 3 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. The thickness (T8) of the eighth lens (208) 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.

[0357]

[0358] The thickness of each lens can satisfy any of the conditions below.

[0359] Condition 1: 2 < CT1 / ET1 < 2.5, 0.1 < ET1 / CT1 < 0.5

[0360] Condition 2: 0.5 < CT2 / ET2 < 1, 1.5 < ET2 / CT2 < 2

[0361] Condition 3: 2 < CT4 / ET4 < 2.5, 0.1 < ET4 / CT4 < 0.5

[0362] Condition 4: 1.5 < CT5 / ET5 < 2, 0.5 < ET5 / CT5 < 1

[0363] Condition 5: 0.1 < CT6 / ET6 < 0.5, 2.5 < ET6 / CT6 < 3

[0364] Condition 6: 0.5 < CT7 / ET7 < 1, 1 < ET7 / CT7 < 1.5

[0365] Condition 7: 1 < CT8 / ET8 < 1.5, 0.5 < ET8 / CT8 < 1

[0366] Condition 8: 1 < ΣCT / ΣET < 1.5, 0.5 < ΣET / ΣCT < 1

[0367]

[0368] Among the gaps (G1-G7) 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 at the edge and a maximum at the center. The gap (LG3) between the third and fourth lenses (203, 204) may have a maximum at the edge and a minimum at the center. The gap (G4) between the fourth and fifth lenses (204, 205) may have a maximum at the edge and a minimum at the center. The fifth gap (G5) between the fifth and sixth lenses (205, 206) may have a maximum at the center and a minimum at the edge. The sixth gap (G6) between the sixth and seventh lenses (206, 207) may have a maximum at the center and a minimum at the edge. The seventh gap (G7) between the seventh and eighth lenses (207, 208) may be maximum at the center and minimum at the edge. The eighth gap (G8) between the eighth and ninth lenses (208, 209) may be minimum at the center and maximum at the edge.

[0369]

[0370] Fig. 4 is a graph showing the aberration characteristics of the optical system according to the second embodiment. For example, Fig. 4 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. 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 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 435 nm, about 470 nm, about 510 nm, about 555 nm, about 610 nm, and 650 nm, and the graph for astigmatism and distortion is a graph for light in wavelength bands of about 555 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 (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.

[0371]

[0372] Fig. 13 is a graph showing the relative illumination versus relative field (RI) of the optical system according to the second embodiment operating in the first mode, and Fig. 14 is a graph showing the relative illumination of the optical system according to the second embodiment operating in the second mode. Figs. 13 and 14 are graphs showing the relative illumination (RI) from the center of the image sensor in the optical system to the image height (MaxF = 1F), that is, from 0 to the maximum height. It can be seen that the relative illumination of 30% or more, for example, more than 40%, is shown from the center of the image sensor to the diagonal end (1.0F). That is, it can be seen that the difference in the peripheral illumination in the first mode and the second mode of the second embodiment is almost the same from the optical axis to the end of the effective area. Accordingly, since the minimum light quantity from the center to the edge of the image sensor exceeds 40%, more accurate sensing values ​​can be obtained across the entire area of ​​the image sensor.

[0373]

[0374]

[0375] An optical system according to the third embodiment of the invention will be described.

[0376] FIG. 15 is a configuration diagram of an optical system according to the third embodiment of the present invention operating in the first mode, FIG. 16 is a configuration diagram of an optical system according to the third embodiment of the present invention operating in the second mode, FIG. 17 is a table showing aspherical coefficients of lenses in the optical system according to the third embodiment of the present invention, FIG. 18 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, FIG. 19 is a graph showing data on aberration characteristics of the optical system according to the third embodiment of the present invention operating in the second mode, FIG. 20 is a graph showing the relative illumination versus relative field of the optical system according to the third embodiment of the present invention operating in the first mode, and FIG. 21 is a graph showing the peripheral illumination ratio of the optical system according to the third embodiment of the present invention operating in the second mode.

[0377] Referring to FIG. 15, the optical system (1200) includes a lens unit, and the lens unit may include first to eighth lenses (301 to 308). The first to eighth lenses (301 to 308) 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 eighth lenses (301 to 308) and the filter (500) and be incident on the image sensor (400).

[0378]

[0379] 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 on the optical axis (OA). The first lens (301) may include a plastic or glass material. For example, the first lens (301) may be provided as a plastic material.

[0380] The first surface (S1) on the object side of the first lens (301) may be convex with respect to the optical axis (OA), and the second surface (S2) on the sensor side may be concave. The first lens (301) may have a meniscus shape that is convex toward the object side. The first lens (301) may have a meniscus shape that is concave toward the sensor side. The first lens (301) may have an aspherical surface. The aspherical coefficients of the first surface (S1) and the second surface (S2) may be provided as L1S1 and L1S1 of FIG. 17. 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.

[0381]

[0382] The second lens (302) may be arranged second from the object side. The second lens (302) may be arranged seventh from the sensor side. The second lens (302) may be arranged between the first lens (301) and the third lens (303). The second lens (302) may have negative refractive power on the optical axis (OA). The second lens (302) may include a plastic or glass material. For example, the second lens (302) may be provided as a plastic material.

[0383] The object-side third surface (S3) of the second lens (302) with respect to the optical axis (OA) may be concave, and the sensor-side fourth surface (S4) may be concave. The second lens (302) may have a concave shape on both sides. The second lens (302) may have an aspherical surface. The aspherical coefficients of the third surface (S3) and the fourth surface (S4) may be provided as L2S1 and L2S1 of FIG. 17. At least one or both of the third surface (S3) and the fourth surface (S4) of the second lens (302) may be provided without a critical point from the optical axis to the end of the effective area.

[0384]

[0385] The third lens (303) may be arranged third from the object side. The third lens (303) may be arranged sixth 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 include a plastic or glass material. For example, the third lens (303) may be provided as a glass material. The fifth surface (S5) on the object side and the sixth surface (S6) on the sensor side of the third lens (303) may be formed as a flat surface.

[0386] The third lens (303) may be a prism lens. The third lens (303) may be a right-angle prism lens. The third lens (303) may be a mirror. The third lens (303) may be a light path control member. The third lens (303) may change the path of light incident from the outside. The third lens (303) may include a reflector and a prism. The third lens (303) may rotate the light path by 90 degrees. The third lens (303) includes an incident surface (S5) on which light is incident, a reflective surface (RS1) that reflects the incident light, and an exit surface (S6) 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 fourth lens (304). The third lens (303) 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).

[0387] In addition, in order to reduce the length in the first axis (Y-axis) direction of the optical system, the angle formed by the reflection surface (RS1) and the exit surface (S6) in the third lens (303) can be changed from about 45 degrees to about 43 degrees or about 47 degrees. The angle formed by the reflection surface (RS1) and the exit surface (S6) in the third lens (303) can be changed to be greater than or less than about 45 degrees depending on the position where the image sensor is placed.

[0388] For example, when the direction of light incident on the lens disposed on the object side of the third lens (303) and the direction of light incident on the image sensor are the same direction, the angle formed by the reflection surface (RS1) and the exit surface (S6) of the third lens (303) can be changed to about 43 degrees. When the direction of light incident on the lens disposed on the object side of the third lens (303) and the direction of light incident on the image sensor are opposite directions, the angle formed by the reflection surface (RS1) and the exit surface (S6) of the third lens (303) can be changed to about 47 degrees. Through this, the size of the optical system can be reduced within a range that has little effect on the change in the performance of the optical system.

[0389]

[0390] The fourth lens (304) may be arranged fourth from the object side. The fourth lens (304) may be arranged fifth 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 positive 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.

[0391] 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 convex. The fourth lens (304) may have a shape in which both sides are convex. 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. 17. 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.

[0392]

[0393] The fifth lens (305) may be arranged as the fifth lens from the object side. The fifth lens (305) may be arranged as the fourth 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 negative (-) 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.

[0394] With respect to the optical axis (OA), the ninth surface (S9) on the object side of the fifth lens (305) may be concave, and the tenth surface (S10) on the sensor side may be concave. The fifth lens (305) may have a concave shape on both sides. 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. 17. 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.

[0395]

[0396] The sixth lens (306) may be arranged as the sixth lens from the object side. The sixth lens (306) may be arranged as the third 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 negative (-) 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.

[0397] With respect to the optical axis (OA), the object-side eleventh surface (S11) of the sixth lens (306) may be concave, and the sensor-side twelfth surface (S12) may be concave. The sixth lens (306) may have a concave shape on both sides. The sixth lens (306) 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. 17. 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.

[0398]

[0399] The seventh lens (307) may be arranged as the seventh lens from the object side. The seventh lens (307) may be arranged as the second lens from the sensor side. The seventh lens (307) may be arranged between the sixth lens (306) and the eighth lens (308). 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 as a plastic material.

[0400] 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. 17. At least one or both of the 13th surface (S13) and the 14th surface (S14) of the seventh lens (307) may be provided without a critical point from the optical axis to the end of the effective area.

[0401]

[0402] The eighth lens (308) may be arranged closest to the sensor side. The eighth lens (308) may be arranged farthest from the object side. The eighth lens (308) may be arranged between the seventh lens (307) and the filter (500). The eighth lens (308) may be arranged between the seventh lens (307) and the image sensor (400). The eighth lens (308) may include a plastic or glass material. For example, the eighth lens (308) may be provided as a glass material. The object-side 15th surface (S15) and the sensor-side 16th surface (S16) of the eighth lens (308) may be formed as a flat surface.

[0403] The eighth lens (308) may be a prism lens. The eighth lens (308) may be a right-angle prism lens. The eighth lens (308) may be a light path control member. The eighth lens (308) may change the path of light incident from the outside. The eighth lens (308) may include a reflector and a prism. The eighth lens (308) may rotate the light path by 90 degrees. The eighth lens (308) includes an incident surface (S15) on which light is incident, a reflective surface (RS15) that reflects the incident light, and an exit surface (S16) that emits the reflected light. The reflective surface (RS15) 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 filter (500).

[0404]

[0405] LensSurfaceRadiusThicknessndvdClearAperture1S17.1401.4701.54151.0116.940 S220.9760.703 6.6162S3-19.3430.6101.58233.4706.373 S460.7840.917 5.9773S5Infinity6.520 6.500 S6Infinity0.640 9.3324S711.6641.5001.53655.6995.895 S8-8.6380.050 5.6695S9-81.5061.0511.62423.7985.298 S1023.804 Variable (D1) 4.7406 S11-17.86 11.4331.58432.8884.906 S1223.024 0.050 4.7957 S134.739 1.5001.67819.2304.845 S144.027 Variable (D2) 4.9478 S15 Infinity 4.960 5.747 S16 Infinity 0.300 6.271 Filter infinity 0.210 6.902 infinity 0.300 6.950 Image infinity 0.000 7.058

[0406] 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.

[0407] In Table 7, the thickness of the third lens (303) and the eighth lens (308), which are prism lenses, may refer to the thickness along the optical axis (OA). For example, the thickness of the third lens (303) may refer to the sum of the thickness from the object side (S5) to the reflective surface (RS1) on the y-axis and the thickness from the reflective surface (RS1) to the sensor side (S6) on the x-axis. In addition, the thickness of the third lens (303) from the object side (S5) to the reflective surface (RS1) on the y-axis and the thickness of the third lens (303) from the reflective surface (RS1) to the sensor side (S6) on the x-axis may be the same. According to a variation, the thickness from the object side (S5) to the reflective surface (RS1) on the y-axis of the third lens (303) and the thickness from the reflective surface (RS1) to the sensor side (S6) on the x-axis of the third lens (303) and the eighth lens (308) may be different.

[0408] Although not listed in Table 7, if the third lens (303) and the eighth lens (308) are prism lenses, they may have different refractive indices and Abbe numbers depending on the material used to make the prism lenses. The third lens (303) and the eighth lens (308) may be mirrors as optical path control elements.

[0409]

[0410] Mode 1 Mode 2 D11.9253.761 D23.5371.701

[0411] 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 either the first or second mode. 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 200 mm) is photographed.

[0412] In the optical system according to the third embodiment, the distance between adjacent lens groups may change during the process of changing from the first mode to the second mode. The first lens group (LG1), the second lens group (LG2), the third lens group (LG3), and the fifth lens group (LG5) are fixed, and only the fourth lens group (LG4) can move. The first lens group (LG1), the second lens group (LG2), the third lens group (LG3), and the fifth lens group (LG5) may be fixed groups, and the fourth lens group (LG4) may be a moving group.

[0413] When operating from the first mode to the second mode, the distance (D1) between the third lens group (LG3) and the fourth lens group (LG4) may increase, and the distance (D2) between the fourth lens group (LG2) and the fifth lens group (LG5) may decrease. When operating from the second mode to the first mode, the distance (D1) between the third lens group (LG3) and the fourth lens group (LG4) may decrease, and the distance (D2) between the fourth lens group (LG2) and the fifth lens group (LG5) may increase.

[0414] The stroke length of the fourth lens group (LG4) can satisfy 1.5 mm to 2 mm, and preferably, can satisfy about 1.836 mm. As the fourth lens group (LG4) moves, the optical performance of the optical system (1200) can change. For example, as the fourth lens group (LG4) moves, the angle of view (FOV), EFL (f), Fno, BFL, etc. of the optical system (1200) can change.

[0415]

[0416] EFL(F)19.500EPD6.940BFL_10.810HFOV_110.150BFL_20.810HFOV_210.150TD27.165TD_LG12.783f119.302TD_LG32.601f2-25.135TD_LG42.983f49.508f_LG160.464f5-29.435f_LG39.508f6-16.995f_LG4-8.567f7-264.981f_(LG3+LG4)28.580ET10.722LG4_stroke1.836ET21.082TTL27.675ET40.677ImgH7.058 ET51.187ΣCT19.044ET61.671ΣCG7.822ET71.474CA_Max7.916L_CT_max6.520CA_Min4.851L_CT_min0.610CA_Aver5.928L_CT_aver2.380Fno2.809

[0417] Table 9 shows the items of the mathematical formulas described above in the optical system (1200) of the third 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 horizontal field of view (HFOV_1 (degree)) in the first mode, the horizontal field of view (HFOV_2 (degree)) in the second mode, the focal lengths (f1 to f8) (mm) of the first to eighth lenses (301 to 308), the edge thicknesses (ET1 to ET8), the lengths of each lens group in the optical axis direction (TD_LG1, TD_LG3, TD_LG4), the focal lengths (f_LG1, f_LG3, f_LG4)(mm), the size of the entrance pupil (EPD (mm)), the optical axis distance from the aperture (STOP) to the 16th surface (S16) (SD (mm)), the optical axis distance from the first lens (301) to the eighth lens (308) (TD (mm)), the brightness (Fno) of the optical system (1200), the stroke length (LG4_stroke) of the fourth lens group (LG4), 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 eighth lenses (301 to 308), etc.

[0418]

[0419] Hereinafter, the center thicknesses of the first to eighth lenses (301 to 308) are represented by CT1 to CT8, the edge thicknesses at the ends of the effective areas of each lens are represented by ET1 to ET8, and the center gap between two adjacent lenses is represented by CG1 to CG7. The back focal length (BFL) is the optical axis distance from the image sensor (400) 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 (400). Hereinafter, some of the descriptions regarding the size relationship between the third lens (303), which is a prism lens, and the eighth lens (308) are omitted.

[0420]

[0421] When comparing the absolute values ​​of the curvature radii of each lens, the curvature radii of the ninth surface (S9) of the fifth lens (305) on the optical axis (OA) may be the largest among the lenses, and the curvature radii of the fourteenth surface (S14) of the seventh lens (307) 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 third surface (S3) of the second lens (302) may be smaller than the absolute value of the curvature radii of the fourth surface (S4). 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 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 (306) may be less 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 greater than the absolute value of the curvature radius of the fourteenth surface (S14).

[0422]

[0423] The ratio of the radius of curvature of each lens can satisfy the following conditions.

[0424] Condition 1: 0.1 < |L1R1 / L1R2| < 0.5

[0425] Condition 2: 0.1 < |L2R1 / L2R2| < 0.5

[0426] Condition 3: 1 < |L4R1 / L4R2| < 1.5

[0427] Condition 4: 3 < |L5R1 / L5R2| < 5

[0428] Condition 5: 0.5 < |L6R1 / L6R2| < 1

[0429] Condition 6: 1 < |L7R1 / L7R2| < 1.5

[0430]

[0431] When describing the central thickness of the lenses based on the optical axis, the central thicknesses (CT4, CT7) of the fourth lens (304) and the seventh lens (307) are the largest among the lenses, and the central thickness (CT2) of the second lens (302) is 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 0.8 mm or more and 1.3 mm or less.

[0432] The central thickness of each lens may satisfy any one of the following conditions:

[0433] Condition 1: CT4, CT7 > CT1 > CT2, CT5, CT6

[0434] Condition 2: CT1, CT4, CT5, CT6, CT7 > CT2

[0435] Condition 3: CT4 = CT7 > CT1, CT2, CT5, CT6

[0436] Condition 4: CT1, CT4, CT6, CT7 > CT5 > CT2

[0437] Condition 5: CT1, CT4, CT7 > CT6 > CT2, CT5

[0438]

[0439] 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, but the distance (CG5) between the fifth lens (305) and the sixth lens (306) and the distance (CG7) between the seventh lens (307) and the eighth lens (308) can change. Among the center spacings between the unchanging lenses, the spacing (CG2) between the second lens (302) and the third lens (303) may be the maximum, and the spacing (CG4) between the fourth lens (304) and the fifth lens and the spacing (CG6) between the sixth lens (306) and the seventh lens (307) may be the minimum. The difference between the maximum center spacing and the minimum center spacing among the lens spacings may be 0.5 mm or more, for example, in the range of 0.5 mm to 1 mm.

[0440] The center spacing between each lens can satisfy the conditions below.

[0441] Condition 1: CG2 > CG1 > CG3, CG4, CG6

[0442] Condition 2: CG2 > CG1, CG3, CG4, CG6

[0443] Condition 3: CG1, CG2 > CG3 > CG4, CG6

[0444] Condition 4: CG1, CG2, CG3 > CG4 = CG6

[0445]

[0446] 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 on the object side and the sensor side of each lens. The lens surface having the maximum effective diameter may be the sixth surface (S6) of the third lens (303). The lens having the minimum effective diameter may be the sixth lens (306). The lens surface having the minimum effective diameter may be the tenth surface (S10) of the fifth lens (305).

[0447] The effective diameter of each lens can satisfy any one of the conditions below.

[0448] Condition 1: CA_L1 > CA_L2, CA_L4, CA_L5, CA_L6, CA_L7

[0449] Condition 2: CA_L1 > CA_L2 > CA_L4, CA_L5, CA_L6, CA_L7

[0450] Condition 3: CA_L1, CA_L2 > CA_L4 > CA_L5, CA_L6, CA_L7

[0451] Condition 4: CA_L1, CA_L2, CA_L4 > CA_L5 > CA_L6, CA_L7

[0452] Condition 5: CA_L1, CA_L2, CA_L4, CA_L5, CA_L7 > CA_L6

[0453] Condition 6: CA_L1, CA_L2, CA_L4, CA_L5 > CA_L7 > CA_L6

[0454]

[0455] Regarding the refractive index, the refractive index of the seventh lens (307) may be the highest among the lenses and may be greater than 1.6, for example, greater than 1.65. The fourth lens (304) may have the lowest refractive index among the lenses. For example, the refractive index of the fourth lens (304) may be the lowest among the lenses and may be less than 1.6, for example, less than 1.55. The difference between the maximum refractive index and the minimum refractive index may be 0.1 or more.

[0456] The refractive index of each lens can satisfy any of the conditions below.

[0457] Condition 1: n2, n5, n6, n7 > n1 > n4

[0458] Condition 2: n5, n6, n7 > n2 > n1, n4

[0459] Condition 3: n1, n2, n5, n6, n7 > n4

[0460] Condition 4: n7 > n5 > n1, n2, n4, n6

[0461] Condition 5: n5, n7 > n6 > n1, n2, n4

[0462] Condition 6: n7 > n1, n2, n4, n5, n6

[0463]

[0464] Comparing the Abbe numbers, the Abbe number of the fourth lens (304) is the largest among the lenses and may be 50 or more. The Abbe number of the seventh lens (307) is 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.

[0465] The Abbe number of each lens can satisfy any of the conditions below.

[0466] Condition 1: v4 > v1 > v2, v5, v6, v7

[0467] Condition 2: v1, v4 > v2 > v5, v6, v7

[0468] Condition 3: v4 > v1, v2, v5, v6, v7

[0469] Condition 4: v1, v2, v4, v6 > v5 > v7

[0470] Condition 5: v1, v2, v4 > v6 > v5, v7

[0471] Condition 6: v1, v2, v4, v5, v6 > v7

[0472]

[0473] The focal lengths (F1, F4) of the first and fourth lenses (301, 304) may have positive (+) signs. The first and fourth lenses (301, 304) may have positive (+) refractive power. The focal lengths (F2, F5, F6, F7) of the second, fifth, sixth, and seventh lenses (302, 305, 306, 307) may have negative (-) signs. The second, fifth, sixth, and seventh lenses (302, 305, 306, 307) may have negative (-) refractive power.

[0474] When comparing the focal lengths in absolute values, the focal length of the seventh lens (307) is the largest among the lenses, and may be 250 or more and 300 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.

[0475] The absolute value of the focal length of each lens can satisfy any of the conditions below.

[0476] Condition 1: |f2|, |f5|, |f7| > |f1| > |f4|, |f6|

[0477] Condition 2: |f5|, |f7| > |f2| > |f1|, |f4|, |f6|

[0478] Condition 3: |f1|, |f2|, |f5|, |f6|, |f7| > |f4|

[0479] Condition 4: |f7| > |f5| > |f1|, |f2|, |f4|, |f6|

[0480] Condition 5: |f1|, |f2|, |f5|, |f7| > |f6| > |f4|

[0481] Condition 6: |f7| > |f1|, |f2|, |f4|, |f5|, |f6|

[0482]

[0483] 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_LG3) of the third lens group (LG3) can have a positive (+) sign. The third lens group (LG3) can have a positive (+) composite refractive power. The composite focal length (f_LG4) of the fourth lens group (LG4) can have a negative (-) sign. The fourth lens group (LG4) 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.

[0484] When comparing the absolute values ​​of the composite focal lengths of the first lens group (LG1), the third lens group (LG3), and the fourth lens group (LG4), the composite focal length of the first lens group (LG1) may be the largest, and the composite focal length of the fourth lens group (LG4) may be the smallest. The relationship between the composite focal lengths of the first lens group (LG1), the third lens group (LG3), and the fourth lens group (LG4) may satisfy |f_LG1| > |f_LG3| > |f_LG4|.

[0485]

[0486] The thickness (CT1) of the first lens (301) may be at least twice the difference between the maximum thickness and the minimum thickness, for example, in the range of 2 to 2.5 times, and the center thickness (CT1) may be maximum and the edge thickness (ET1) may be minimum. The thickness (T2) of the second lens (302) may be minimum at the center and maximum at the edge, and the maximum thickness is in the range of 1.5 to 2 times the minimum thickness. The thickness (T4) of the fourth lens (304) may be maximum at the center and minimum at the edge, and the maximum thickness is in the range of 2 to 2.5 times the minimum thickness. The thickness (T5) of the fifth lens (305) 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 (T6) of the sixth lens (306) 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 (307) 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.

[0487]

[0488] The thickness of each lens can satisfy any of the conditions below.

[0489] Condition 1: 2 < CT1 / ET1 < 2.5, 0.1 < ET1 / CT1 < 0.5

[0490] Condition 2: 0.5 < CT2 / ET2 < 1, 1.5 < ET2 / CT2 < 2

[0491] Condition 3: 2 < CT4 / ET4 < 2.5, 0.1 < ET4 / CT4 < 0.5

[0492] Condition 4: 0.5 < CT5 / ET5 < 1, 1 < ET5 / CT5 < 1.5

[0493] Condition 5: 0.5 < CT6 / ET6 < 1, 1 < ET6 / CT6 < 1.5

[0494] Condition 6: 1 < CT7 / ET7 < 1.5, 0.5 < ET7 / CT7 < 1

[0495] Condition 7: 1 < ΣCT / ΣET < 1.5, 0.5 < ΣET / ΣCT < 1

[0496]

[0497] Among the gaps (G1-G7) between the lenses, the gap (LG1) between the first and second lenses (301, 302) may be maximum at the center and minimum at the edge. The gap (LG2) between the second and third lenses (302, 303) may be minimum at the edge and maximum at the center. The gap (LG3) between the third and fourth lenses (303, 304) may be maximum at the edge and minimum at the center. The gap (G4) between the fourth and fifth lenses (304, 305) may be maximum at the edge and minimum at the center. The fifth gap (G5) between the fifth and sixth lenses (305, 306) may be maximum at the center and minimum at the edge. The sixth gap (G6) between the sixth and seventh lenses (306, 307) may be minimum at the center and maximum at the edge. The seventh gap (G7) between the seventh and eighth lenses (307, 308) may be maximum at the center and minimum at the edge.

[0498]

[0499] Fig. 4 is a graph showing the aberration characteristics of the optical system according to the third embodiment. For example, Fig. 4 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. 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 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 435 nm, about 470 nm, about 510 nm, about 555 nm, about 610 nm, and 650 nm, and the graph for astigmatism and distortion is a graph for light in wavelength bands of about 555 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 (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.

[0500]

[0501] Fig. 20 is a graph showing the relative illumination versus relative field (RI) of the optical system according to the third embodiment operating in the first mode, and Fig. 21 is a graph showing the relative illumination of the optical system according to the third embodiment operating in the second mode. Figs. 20 and 21 are graphs showing the relative illumination (RI) from the center of the image sensor in the optical system to the image height (MaxF = 1F), that is, from 0 to the maximum height. It can be seen that the relative illumination of 40% or more, for example, more than 50%, is shown from the center of the image sensor to the diagonal end (1.0F). That is, it can be seen that the difference in the peripheral illumination in the first mode and the second mode of the second embodiment is almost the same from the optical axis to the end of the effective area. Accordingly, since the minimum light quantity from the center to the edge of the image sensor exceeds 40%, more accurate sensing values ​​can be obtained across the entire area of ​​the image sensor.

[0502]

[0503] The optical system (1000 to 1200) according to the present embodiment disclosed above can satisfy at least one or two or more of the mathematical equations described below. Accordingly, the optical system (1000 to 1200) according to the present embodiment can have improved optical characteristics. For example, when the optical system (1000 to 1200) satisfies at least one mathematical equation, the optical system (1000 to 1200) 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 system (1000 to 1200) can have improved resolution. In addition, the thickness of the lens on the optical axis (OA) described in the mathematical equations and the spacing between adjacent lenses on the optical axis (OA) can refer to the present embodiment disclosed above.

[0504]

[0505] [Mathematical Formula 1]

[0506] 0.5 < TD_LG1 / TD_LG3 < 1.5

[0507] Mathematical expression 1 can establish the relationship between the length (TD_LG1) of the first lens group (LG1) 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.

[0508] The first lens group (LG1) and the third lens group (LG3) satisfying mathematical expression 1 can appropriately correct astigmatism and coma aberration. In addition, the overall length of a zoom optical system having an appropriate zoom ratio can be reduced. In the present embodiment, mathematical expression 1 preferably satisfies 0.7 < TD_LG1 / TD_LG3 < 1.1.

[0509]

[0510] [Equation 2]

[0511] 17 < EFL(F) < 20

[0512] In mathematical expression 2, EFL(F) is the total focal length of the optical system (1000~1200). Mathematical expression 2 is a condition for limiting zoom optical performance. If the upper limit of mathematical expression 2 is exceeded, 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 19 < EFL(F) < 20 in the present embodiment.

[0513]

[0514] [Equation 3]

[0515] 0.5 < BFL_1 < 1

[0516] In mathematical expression 3, BFL is the optical axis distance from the image sensor (400) 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 (500) and the cover glass can be secured, the assembling of the components can be improved through the gap between the image sensor (400) and the last lens, and the joining reliability can be improved. In the present embodiment, mathematical expression 3 can preferably satisfy 0.7 < BFL_1 < 0.9. 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.

[0517]

[0518] [Equation 4]

[0519] 35 < Ave_ABV < 45

[0520] In mathematical expression 4, Ave_ABV is the average Abbe number of the lenses included in the optical system (1000 to 1200). When mathematical expression 4 is satisfied, optical performance can be improved by appropriately setting factors affecting chromatic aberration. In the present embodiment, mathematical expression 4 preferably satisfies 35 < Ave_ABV < 42.

[0521]

[0522] [Equation 5]

[0523] 1.5 < Ave_Ind < 1.6

[0524] In mathematical expression 5, Ave_Ind is the average refractive index of the lenses included in the optical system (1000 to 1200). When mathematical expression 5 is satisfied, optical performance can be improved by appropriately setting factors affecting chromatic aberration. In the present embodiment, mathematical expression 4 preferably satisfies 1.55 < Ave_Ind < 1.6.

[0525]

[0526] [Equation 6]

[0527] 1.5 < |f_LG1 / f_(LG3+LG4)| < 3

[0528] Mathematical expression 6 can set the relationship between the focal length (f_LG1) of the first lens group (LG1) and the composite focal length (f_(LG3+LG4)) of the third lens group (LG3) and the fourth lens group (LG4). Mathematical expression 6 is a condition for reducing aberration and improving optical performance. The first lens group (LG1), the third lens group (LG3), and the fourth lens group (LG4) that satisfy Mathematical expression 6 can appropriately correct astigmatism and coma. Mathematical expression 6 can preferably satisfy 1.8 < |f_LG1 / f_(LG3+LG4)| < 2.8 in the present embodiment.

[0529]

[0530] [Equation 7]

[0531] 20 < f_(LG3+LG4) < 30

[0532] In mathematical expression 7, f_(LG3+LG4) is the composite focal length of the third lens group (LG3) and the fourth lens group (LG4). Mathematical expression 7 is a condition for reducing aberration and improving optical performance. In the present embodiment, mathematical expression 7 can preferably satisfy 23 < f_(LG3+LG4) < 30.

[0533]

[0534] [Equation 8]

[0535] 1 < LG4_stroke < 3

[0536] Mathematical expression 8 can set the range of the stroke length (LG4_stroke) of the fourth lens group (LG4). If it exceeds the upper limit of Mathematical expression 8, the stroke length of the fourth lens group (LG4) 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 1.4 < LG4_stroke < 2.8 in the present embodiment.

[0537]

[0538] [Equation 9]

[0539] 0.5 < EFL(F) / F1 < 1.5

[0540] In mathematical expression 9, EFL(F) is the total effective focal length of the optical system (1000 to 1200), and F1 is the focal length of the first lens (101). When mathematical expression 9 is satisfied, the optical system (1000 to 1200) can have a set angle of view and an appropriate focal length, and can set the angle of view to be large in an appropriate TTL range. When it is less than 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 more than the upper limit of mathematical expression 9, the influence of the first lens (101) becomes small in the entire optical system, 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 present embodiment, mathematical expression 9 can preferably satisfy 0.8 < EFL(F) / F1 < 1.2.

[0541]

[0542] [Equation 10]

[0543] 1 < CT1 < 2

[0544] In mathematical expression 10, CT1 is the central thickness of the first lens (101). When mathematical expression 10 is satisfied, the thickness of the optical system (1000 to 1200) in the first direction (y-axis direction) can be prevented from increasing, and a miniaturized optical system can be implemented. In the present embodiment, mathematical expression 10 preferably satisfies 1.3 < CT1 < 1.5.

[0545]

[0546] [Equation 11]

[0547] 20 < TTL < 30

[0548] 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 the upper surface of the image sensor (400) on the optical axis (OA). In this embodiment, mathematical expression 11 can preferably satisfy 23 < TTL < 28.

[0549]

[0550] [Equation 12]

[0551] 6.5 < ImgH < 7.5

[0552] In mathematical expression 12, ImgH represents the maximum diagonal length of the image sensor (400). Mathematical expression 12 can set the diagonal size (ImgH) of the image sensor (400) and provide an optical system having a large mobile image sensor size. In the present embodiment, mathematical expression 12 can preferably satisfy 6.8 < ImgH < 7.5.

[0553]

[0554] [Equation 13]

[0555] 2 < Fno < 3

[0556] Mathematical expression 13 can set the range of Fno of the optical system (1000~1200). 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 present embodiment, mathematical expression 13 preferably satisfies 2.7 < Fno < 3.

[0557]

[0558] [Equation 14]

[0559] 8 < FOV_1 < 12

[0560] In mathematical expression 14, the range of the field 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 present embodiment, the FOV preferably satisfies 9 < FOV_1 < 11.

[0561]

[0562] [Equation 15]

[0563] 3 < TTL / CA_max < 5

[0564] 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 the upper surface of the image sensor (400) 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 present embodiment, mathematical expression 15 can preferably satisfy 3 < TTL / CA_max < 4.

[0565]

[0566] [Equation 16]

[0567] 3 < TTL / ImgH < 5

[0568] In mathematical expression 16, TTL (Total track length) means the distance (mm) from the vertex of the first surface (S1) of the first lens to the upper surface of the image sensor (400) on the optical axis (OA), and ImgH means the maximum diagonal length of the image sensor (400). When mathematical expression 16 is satisfied, the optical system (1000 to 1200) can have TTL for application to the mobile image sensor (400), thereby providing improved image quality. When it is less than the lower limit of mathematical expression 16, 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 present embodiment, mathematical expression 16 can preferably satisfy 3 < TTL / ImgH < 4.

[0569]

[0570] [Equation 17]

[0571] 2 < EFL(F) / ImgH < 4

[0572] In mathematical expression 17, EFL(F) is the total effective focal length of the optical system (1000-1200), and ImgH means the maximum diagonal length of the image sensor (400). When mathematical expression 17 is satisfied, the mobile image sensor (400) can have improved aberration characteristics in terms of its size. In the present embodiment, mathematical expression 17 can preferably satisfy 2.5 < EFL(F) / ImgH < 3.

[0573]

[0574] [Equation 18]

[0575] 0.1 < ΣCT / TTL < 1

[0576] 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 (400) on the optical axis (OA). If the upper limit of Mathematical expression 18 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 18 is less than the lower limit of Mathematical expression 18, the focusing performance of the optical system may deteriorate. In the present embodiment, Mathematical expression 18 can preferably satisfy 0.5 < ΣCT / TTL < 1.

[0577]

[0578] [Equation 19]

[0579] 0.1 < ΣCG / TTL < 1

[0580] 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 (400) 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 present embodiment, Mathematical expression 19 can preferably satisfy 0.1 < ΣCG / TTL < 0.5.

[0581]

[0582] [Equation 20]

[0583] 2 < ΣCT / ΣCG < 3

[0584] 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 moving 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 present embodiment, Mathematical expression 20 can preferably satisfy 2.1 < ΣCT / ΣCG < 2.5.

[0585]

[0586] [Equation 21]

[0587] 1 < CA_max / CA_min < 2.5

[0588] 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 present embodiment, mathematical expression 21 can preferably satisfy 1.6 < CA_max / CA_min < 2.1.

[0589]

[0590] [Equation 22]

[0591] 1 < CA_max / ImgH < 2

[0592] 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 (400). 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 present embodiment, mathematical expression 22 can preferably satisfy 1 < CA_max / ImgH < 1.5.

[0593]

[0594] [Equation 23]

[0595] 0.1 < CA_min / ImgH < 1

[0596] 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 (400). 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 present embodiment, mathematical expression 23 can preferably satisfy 0.5 < CA_min / ImgH < 0.7.

[0597]

[0598] [Equation 24]

[0599] 0.5 < CG2 < 1

[0600] In mathematical expression 24, CG2 is the center distance between the second lens (102 to 302) and the third lens (103 to 303). 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. In the first to fourth embodiments, mathematical expression 24 can preferably satisfy 0.8 < CG2 < 1.

[0601]

[0602] [Equation 25]

[0603] 0.5 < CG3 < 1

[0604] In mathematical expression 25, CG3 is the center distance between the third lens (103 to 303) and the fourth lens (104 to 304). 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 that interference occurs 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 0.6 < CG3 < 0.8.

[0605]

[0606] [Equation 26]

[0607] 1 < TTL / F1 < 1.5

[0608] In mathematical expression 26, F1 is the focal length of the first lens (101 to 301), and F is the effective focal length of the optical system. When mathematical expression 26 is satisfied, the optical system (1000 to 1200) can have a set angle of view and an appropriate focal length. When it is less than the lower limit of mathematical expression 26, the effective diameter or TTL of the lenses may become long, which may cause a problem of the large size of the imaging lens system. When it is more than the upper limit of mathematical expression 26, the influence of the first lens (101 to 301) in the entire optical system becomes small, and the refractive power of the lenses needs to be increased, which causes a problem of difficulty in correcting spherical aberration or distortion aberration. In the first to third embodiments, mathematical expression 26 can preferably satisfy 1.3 < TTL / F1 < 1.5.

[0609]

[0610] [Equation 27]

[0611] 1 < TTL / EFL(F) < 1.5

[0612] In mathematical expression 27, EFL(F) is the effective focal length of the optical system, and TTL (Total track length) means the distance (mm) from the vertex of the first surface (S1) of the first lens (101 to 301) to the image surface of the image sensor (400) on the optical axis (OA). When mathematical expression 27 is satisfied, the optical system (1000 to 1200) can have an appropriate focal length in the set TTL range, and provides an optical system that can form an image while maintaining an appropriate focal length. When it is less than the lower limit of mathematical expression 27, the refractive power of the lenses needs to be increased, making it difficult to correct spherical aberration or distortion aberration, and when it exceeds the upper limit of mathematical expression 27, the effective diameter or TTL of the lenses may become long, which may cause a problem of the imaging lens system becoming larger. In the first to third embodiments, mathematical expression 27 can preferably satisfy 1.2 < TTL / EFL(F) < 1.5.

[0613]

[0614] [Equation 28]

[0615] L1R1 > 0, L4R1 > 0

[0616] In mathematical expression 28, L1R1 is the radius of curvature of the object-side surface of the first lens (101 to 301), and L4R1 is the radius of curvature of the object-side surface of the fourth lens (104 to 304). 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.

[0617]

[0618] [Equation 29]

[0619]

[0620] In mathematical expression 29, 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.

[0621]

[0622] The optical system (1000 to 1200) according to the present embodiment can satisfy at least one or two or more mathematical expressions from mathematical expressions 1 to 29. In this case, the optical system (1000 to 1200) can have improved optical characteristics. Specifically, when the optical system (1000 to 1200) satisfies at least one or two or more mathematical expressions from mathematical expressions 1 to 29, the optical system (1000 to 1200) can have improved resolution and improve aberration and distortion characteristics. In addition, the optical system (1000 to 1200) can secure a BFL (Back focal length) for applying the image sensor (400), can compensate for optical characteristic degradation due to temperature change, and can minimize the gap between the last lens and the image sensor (400), thereby having good optical performance at the center and periphery of the field of view (FOV).

[0623]

[0624] Mathematical Formula Example 1 Example 2 Example 3 Example 10.5 < TD_LG1 / TD_LG3 < 1.5 0.764 0.912 1.070217 < EFL(F) < 2019.50019.50019.50030.5 < BFL_1 < 10.8 100.8100.810435 < Ave_ABV < 4539.46241.23936.01651.5 < Ave_Ind < 1.6 1.5861.5721.59161.5 < |f_LG1 / f_(LG3+LG4)| < 31.9242.7412.116720 < f_(LG3+LG4) < 3029.76124.99128.58181 < LG4_stroke < 31.5002.6271.83690.5 < EFL(F) / F1 < 1.50.9551.0971.010101 < CT1 < 21.4701.4701.4701120 < TTL < 3026.87524.17027.675126.5 < ImgH < 7.57.4587.0577.058132 < Fno < 32.8322.8102.810148 < FOV_1 < 1210.10010.10010.150153 < TTL / CA_max < 53.3953.0533.496163 < TTL / ImgH < 53.6043.4253.921172 < EFL(F) / ImgH < 32.6152.7632.763180.1 < ΣCT / TTL < 10.6690.7650.688190.1 < ΣCG / TTL < 10.2830.3370.283202 < ΣCT / ΣCG < 32.3662.2712.435211 < CA_max / CA_min < 2.52.0031.8241.632221 < CA_max / ImgH < 21.0611.1221.122230.5 < CA_min / ImgH < 10.5300.6150.687240.5 < CG2 < 10.9170.9170.917250.5 < CG3 < 10.6400.6400.640261 < TTL / F1 < 1.51.3161.3591.434271 < TTL / EFL(F) < 1.51.3781.2391.41928L1R1 > 0, L4R1 > 0 Satisfied Satisfied Satisfied.

[0625] Table 10 shows the result values ​​for the mathematical expressions 1 to 28 described above in the optical system (1000 to 1200) of the embodiment. Referring to Table 10, it can be seen that the optical system (1000 to 1200) satisfies at least one, two or more, or three or more of the mathematical expressions 1 to 28. In detail, it can be seen that the optical system (1000 to 1200) according to the embodiment satisfies all of the mathematical expressions 1 to 28. Accordingly, the optical system (1000 to 1200) can have good optical performance and excellent optical characteristics in the center and periphery of the field of view (FOV).

[0626]

[0627] Fig. 23 is an example of a mobile terminal having an optical system according to the present embodiment. As illustrated in Fig. 23, 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.

[0628] 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.

[0629] 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.

[0630] 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.

[0631] 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 being included within the scope of the present invention.

[0632] 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 fifth lens groups arranged along the optical axis, The above first lens group has positive (+) refractive power, The above third lens group has positive (+) refractive power, The above fourth lens group has negative (-) refractive power, The second lens group and the fifth lens group include prism lenses, The above first lens group and the above second lens group move OIS, The above fourth lens group is an AF moving optical system.

2. In paragraph 1, The above first lens group includes a first lens and a second lens, An optical system in which the object-side surface of the first lens has a convex shape on the optical axis.

3. In paragraph 2, The above first lens has positive (+) refractive power, The above second lens is an optical system having negative (-) refractive power.

4. In paragraph 3, An optical system in which the difference between the absolute values ​​of the focal lengths of the first lens and the second lens is 10 or less.

5. In paragraph 1, The second lens group includes a third lens, The third lens group includes a fourth lens and a fifth lens, An optical system in which the object-side surface of the fourth lens on the optical axis has a convex shape.

6. In paragraph 5, The above fourth lens has positive (+) refractive power, The above fifth lens is an optical system having positive (+) refractive power.

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

8. In paragraph 1, An optical system in which the lens placed closest to the object side in the first lens group has a meniscus shape with a convex object side.

9. In paragraph 1, An optical system that satisfies the following conditions. <Conditional expression> 1 < LG4_stroke < 3 (In the above conditional expression, LG4 is the stroke length of the fourth lens group.) 10. In paragraph 2, An optical system that satisfies the following conditions. <Conditional expression> 1 < TTL / F1 < 1.5 (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 F1 is the focal length of the first lens.)

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