Optical system and camera module

Abstract

An optical system disclosed in an embodiment of the present invention comprises: first and second reflective members spaced apart from each other; a first lens group, which is arranged between the first reflective member and an object and has first and second lenses arranged along a first optical axis; and a second lens group, which is arranged between the first and second reflective members and has a plurality of lenses sequentially aligned along a second optical axis, wherein the object-side surfaces of the first and second lenses have a convex shape on the first optical axis, the number of lenses of the second lens group is at least twice the number of lenses of the first lens group, a lens facing the exit surface of the first reflective member has a convex object-side surface, the lens closest to the second reflective member from among the lenses of the second lens group is an n-th lens, n being 6 or greater, the first lens can have positive power, and the second lens can have negative power.

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 resolution has been growing, and research is being conducted on optical systems that incorporate multiple lenses to achieve this. For example, research is underway on utilizing multiple imaging lenses with positive or negative refractive power to achieve high resolution.

[0005] However, when multiple lenses are included, there is a problem in that it is difficult to derive excellent optical characteristics and aberration characteristics. In addition, when multiple lenses are included, the overall length, height, etc. may increase due to the thickness, spacing, size, etc. of the multiple lenses, and as a result, there is a problem in that the overall size of the module including the multiple lenses increases.

[0006] Additionally, image sensor sizes are increasing to achieve high resolution and high image quality. However, as image sensor sizes increase, the TTL (Total Track Length) of optical systems containing multiple lenses also increases, leading to an increase in the thickness of cameras, mobile devices, and other devices containing the optical systems.

[0007] Therefore, a new optical system capable of solving the above-described problems is required.

[0008] An embodiment of the invention can provide an optical system and a camera module having a first lens group having a plurality of lenses between an object and a first reflective member, and a second lens group having a plurality of lenses between the first and second reflective members. Accordingly, an image sensor can be arranged in a direction parallel to an axial direction passing through the centers of the plurality of reflective members. In other words, an optical system and a camera module are provided in which the optical axis of the last lens and the central axis of the image sensor are arranged orthogonal to each other. The embodiment provides a foldable optical system and a camera module having the same.

[0009] An optical system according to an embodiment includes a first reflective member; a second reflective member spaced apart from the first reflective member; a first lens group having first and second lenses arranged along a first optical axis and disposed between the first reflective member and an object; and a second lens group having a plurality of lenses arranged between the first and second reflective members and sequentially aligned along a second optical axis different from the first optical axis, wherein the first lens closest to the object has positive power, object-side surfaces of the first and second lenses have a convex shape on the first optical axis, the number of lenses in the second lens group is at least twice the number of lenses in the first lens group, a lens facing an exit surface of the first reflective member has an object-side surface of a convex shape, and among the lenses in the second lens group, a lens closest to the second reflective member is an n-th lens, where n is 6 or more, and the second lens can have negative power.

[0010] According to an embodiment of the invention, the power of the first lens group may have a positive value. The power of the second lens group may have a positive value.

[0011] According to an embodiment of the invention, the n-1th lens among the lenses of the first and second lens groups may have a minimum effective length among the effective lengths of the lenses.

[0012] According to an embodiment of the invention, the second lens group has third to seventh lenses, the seventh lens being the nth lens, and the second lens group can move along the second optical axis. The first reflective member faces the second lens and the third lens, and the power of the third lens can have positive power. The effective length of the second lens can be greater than the effective length of each of the third to seventh lenses.

[0013] According to an embodiment of the invention, the second lens group has third to sixth lenses, the sixth lens being the nth lens, and the second lens group can move along the second optical axis. The third lens has positive power and can have a convex shape on both sides on the second optical axis. The sensor-side surface of the sixth lens can have a concave shape.

[0014] According to an embodiment of the invention, the nth lens may have negative power. The average of the effective lengths of the first lens may be greater than the average of the effective lengths of the lenses of the second lens group.

[0015] According to an embodiment of the invention, the reflective surface of the first reflective member has an inclination angle R1 with respect to an axis orthogonal to the first optical axis, and can satisfy the mathematical formula: 41 < R1 ≤ 45.

[0016] According to an embodiment of the invention, there is provided an image sensor that converts light reflected from the second reflective member into an electrical signal; and an optical filter disposed between the image sensor and the second reflective member, wherein at least one of the optical filter and the image sensor overlaps the first reflective member in a direction parallel to the second optical axis, and a diagonal length of the image sensor may be greater than an effective length of at least one of the lenses of the second lens group.

[0017] According to an embodiment of the invention, there is provided an image sensor that converts light reflected from the second reflective member into an electrical signal; and an optical filter disposed between the image sensor and the second reflective member, wherein the second reflective member reflects the incident light toward an object, the optical filter and the image sensor are disposed closer to the second reflective member and the object, and a diagonal length of the image sensor may be greater than an effective length of the first lens.

[0018] According to an embodiment of the invention, the first lens group can be moved in the second optical axis direction on the first reflective member.

[0019] According to an embodiment of the invention, the first and second reflective members may be prisms, and the lenses of the first and second lens groups may be aspherical lenses.

[0020] An embodiment of the invention provides an optical system having improved optical characteristics, comprising a plurality of reflective elements and a plurality of lenses. An autofocus (AF) function for a subject can be provided by moving a lens (or group of lenses) located on the object side of a first reflective element adjacent to the object or on the sensor side. Furthermore, OIS can be adjusted using the first reflective element and / or the second reflective element.

[0021] The embodiment can have multiple lenses correct for aberration characteristics or mutually compensate for 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.

[0022] The present invention provides a telescopic optical system capable of minimizing power consumption required depending on the operating mode. The optical system may include at least one lens, included in a fixed group and a moving group, having a non-circular shape. The embodiment may reduce the height of the optical system while maintaining optical performance. Furthermore, the optical system may provide an optical system with a large effective area of ​​a lens surface adjacent to an object, thereby suppressing an increase in the thickness of a portable device having a camera module.

[0023] An optical system according to an embodiment can have improved aberration characteristics and resolution by setting the surface shape, refractive power, thickness, and spacing between adjacent lenses of a plurality of lenses, and the focal length of each lens (group).

[0024] The optical system and camera module according to the embodiment may have improved distortion and aberration control characteristics and may have good optical performance at the center and periphery of the field of view (FOV).

[0025] FIG. 1 is a configuration diagram of an optical system and a camera module according to a first embodiment of the invention.

[0026] Figure 2 is a drawing showing another mode of the optical system of Figures 1 and 2.

[0027] Fig. 3 is a table showing lens data of the optical systems of Figs. 1 and 2.

[0028] Fig. 4 is an example of the aspherical coefficients of the lenses of the optical system of Fig. 1.

[0029] Fig. 5 is an example of adjusting the angle of the reflective surface of the first reflective member of Fig. 1.

[0030] Fig. 6 is an example of changing the light path by the second reflective member of Fig. 1.

[0031] Figures 7 (a) and (b) are drawings showing examples of movement of the first lens group in the second optical axis direction in the optical system of Figure 1.

[0032] (A)(B) of Fig. 8 are graphs showing data of diffraction MTF (Modulation Transfer Function) in the first and second modes of the optical system of Fig. 1.

[0033] Fig. 9 is a graph showing the aberration characteristics in the first mode of the optical system of Fig. 1.

[0034] Fig. 10 is a graph showing the aberration characteristics in the second mode of the optical system of Fig. 2.

[0035] FIG. 11 is a graph showing relative illumination according to the field height of the image sensor in the first and second modes of the optical system according to the first embodiment of the invention.

[0036] Fig. 12 is a configuration diagram of an optical system and a camera module according to a second embodiment of the invention.

[0037] Fig. 13 is a drawing showing another mode of the optical system of Fig. 12.

[0038] Fig. 14 is a table showing lens data of the optical system of Figs. 12 and 13.

[0039] Fig. 15 is an example of the aspherical coefficients of the lenses of the optical system of Fig. 12.

[0040] Fig. 16 is an example of adjusting the angle of the reflective surface of the first reflective member of Fig. 12.

[0041] Fig. 17 is an example of changing the light path by the second reflective member of Fig. 12.

[0042] Figures 18 (a) and (b) are drawings showing examples of movement of the first lens group in the second optical axis direction in the optical system of Figure 2.

[0043] (A)(B) of Fig. 19 are graphs showing data of diffraction MTF (Modulation Transfer Function) in the first and second modes of the optical system of Figs. 11 and 12.

[0044] Fig. 20 is a graph showing the aberration characteristics in the first mode of the optical system of Fig. 12.

[0045] Fig. 21 is a graph showing the aberration characteristics in the second mode of the optical system of Fig. 13.

[0046] FIG. 22 is a graph showing relative illuminance according to the field height of the image sensor in the first and second modes of the optical system according to an embodiment of the invention.

[0047] Fig. 23 is a perspective view of a mobile terminal to which a camera module according to an embodiment of the invention is applied.

[0048] FIG. 24 is a perspective view of a mobile body having a camera module according to an embodiment of the invention.

[0049] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. The technical idea of ​​the present invention is not limited to some of the embodiments described, but can be implemented in various different forms, and one or more of the components between the embodiments can be selectively combined or substituted within the scope of the technical idea of ​​the present invention. In addition, terms (including technical and scientific terms) used in the embodiments of the present invention can be interpreted as having a meaning that can be generally understood by a person having ordinary skill in the technical field to which the present invention belongs, unless explicitly and specifically defined and described, and terms that are commonly used, such as terms defined in a dictionary, can be interpreted in consideration of the contextual meaning of the related technology.

[0050] The terminology used in the embodiments of the present invention is for the purpose of describing the embodiments and is not intended to limit the present invention. In this specification, the singular may also include the plural unless specifically stated in the phrase, and when it is described as “A and (or at least one (or more) of B, C)”, it may include one or more of all combinations that can be combined with A, B, and C. In addition, when describing components of the embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only for distinguishing the components from other components, and are not limited by the nature, order, or sequence of the components. In addition, when it is described that a component is “connected,” “coupled,” or “connected” to another component, it may include not only cases where the component is directly connected, coupled, or connected to the other component, but also cases where the component is “connected,” “coupled,” or “connected” due to another component between the component and the other component. Additionally, when it is 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 it is expressed as "above" or "below", it can include the meaning of a downward direction as well as an upward direction based on one component.

[0051] In the description of the invention, the "object side surface" may mean a surface of the lens facing the object side based on the optical axis (OA), and the "sensor side surface" may mean a surface of the lens facing the imaging surface (image sensor) based on the optical axis. A convex surface of the lens may mean a convex shape in the optical axis or the paraxial region, and a concave surface of the lens may mean a concave shape in the optical axis or the paraxial region. The radius of curvature, thickness, spacing between lenses, focal length, ImgH (Image height), and effective radius described in the table for lens data are in mm, and the radius of curvature is a value on the optical axis or the paraxial region, and the shape of the lens surface is a shape on the optical axis or the paraxial region. The end of the lens or lens surface may mean the end of the effective area of ​​the lens through which incident light passes. The effective length of the lens surface may have a measurement error of up to ±0.4 mm depending on the measurement method, etc. The above-mentioned paraxial 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 concave or convex shape of the lens surface is described as the optical axis, and may also include the paraxial region.

[0052]

[0053] FIG. 1 and FIG. 12 are configuration diagrams of an optical system and a camera module according to embodiments of the invention. Referring to FIG. 1 and FIG. 12, the optical system (1000) or the camera module may include a plurality of lenses and at least one reflective member. The reflective member may include a first reflective member (P1) and a second reflective member (P2) spaced apart in a second optical axis direction (OA2). The first reflective member (P1) reflects or refracts light incident along the first optical axis (OA1) in the direction of the second optical axis (OA2) orthogonal to the first optical axis (OA1). The second reflective member (P2) reflects or refracts light incident along the second optical axis (OA1) in the direction of the optical axis parallel to the first optical axis (OA1). The second reflective member (P2) can reflect or refract light incident on the second optical axis (OA2) toward the upper surface (image surface) of the image sensor (190).

[0054]

[0055] The first reflective member (P1) may be a prism or a mirror, and may be provided as a prism, for example. The second reflective member (P2) may be a prism or a mirror. The optical system (1000) may be provided as a folded optical system. The optical system (1000) may have 5 or more lenses, for example, 5 to 8 lenses, excluding the reflective members (P1, P2). The number of lenses of the optical system (1000) may be 6 or 7. As another example, when there is one reflective member in the optical system (1000), it may be located at the position of the first reflective member or the second reflective member.

[0056] The number of lenses disposed between the first reflective member (P1) and the object may be two or more, for example, two. The number of lenses disposed between the first reflective member (P1) and the second reflective member (P2) may be three or more, for example, three to six. The lenses disposed between the first reflective member (P1) and the object may be defined as a first lens group (LG1), and the lenses disposed between the first reflective member (P1) and the second reflective member (P2) may be defined as a second lens group (LG2).

[0057] At least one of the first and second lens groups (LG1, LG2) can move in the optical axis direction according to the operation mode of the optical system (1000). The first lens group (LG1) arranged between the first reflective member (P1) and the object or the second lens group (LG2) arranged between the first and second reflective members (P1, P2) can move in the optical axis (OA) direction. For example, the first lens group (LG1) can move in the first optical axis (OA1) direction, or the second lens group (LG2) can move in the second optical axis (OA2) direction. The operation mode can be a first mode having a telephoto or long-distance mode, and a second mode having a close-distance or macro mode. The first mode can be an infinity mode, and the second mode is a mode for photographing an object within 50 cm. The above optical system (1000) can operate in a near-distance focusing mode at infinity.

[0058]

[0059] At least one or two of the lenses arranged between the first reflective member (P1) and the second reflective member (P2) may be provided with a structure in which one or both ends of the effective area are cut off. Here, the cut portion may be one or both ends of the lens of the second lens group (LG2) in the third direction (Z). That is, one or both ends of the effective area of ​​a lens having a relatively long effective length may be cut off. Accordingly, the cut lens may have an effective length in the third direction (Z) that is shorter than an effective length in the second direction (Y). By reducing the effective length in the third direction (Z) of the lens of the second lens group (LG2) arranged between the first reflective member (P1) and the second reflective member (P2), the height of the optical system (1000) and the camera module in the third direction (Z) can be reduced. The third direction (Z) is a direction orthogonal to the first and second directions (X, Y) and is a thickness direction of the mobile device. The above-mentioned portable device may be any type of portable electronic device, such as a mobile communication terminal, a smart phone, or a tablet PC.

[0060] The AF (Auto-focusing) function can move at least one or all of the lenses of the first lens group (LG1) or the second lens group (LG2) in the direction of the second optical axis (OA2). Accordingly, the optical system can provide a foldable tele optical system. In addition, the OIS function can be implemented by tilting at least one of the first and second reflective members (P1, P2), for example, the first reflective member (P1) can be tilted. As another example, the OIS function can be implemented by shifting a substrate having an image sensor (190). The lens or lens groups can be moved by a focusing drive unit having a magnet and a coil. The movement of the reflective member can be moved by an OIS drive unit having a magnet and a coil.

[0061]

[0062] The power of the first lens group (LG1) has a positive value. In addition, the power of the first lens (101, 111) closest to the object has a positive value. Accordingly, the first lens group (LG1) and the first lens (101, 111) can refract the incident light to the entire area of ​​the incident surface (PS1) of the first reflective member (P1). The sensor-side surface of the last lens (107, 116) closest to the image sensor (190) may be concave on the optical axis. The last lens (107, 116) can refract the incident light to the entire area of ​​the image sensor (190) through the second reflective member (P2). Accordingly, the resolution can be improved by using the refractive power and the positive and negative focal lengths of each lens. The last lens is the nth lens, where n is 6 or 7. The refractive power is the reciprocal of the power.

[0063]

[0064] The effective length of the first lens (101, 111) may be the largest among the lenses within the optical system (1000). Accordingly, the first lens (101, 111) may improve the amount of incident light. In addition, at least one of the lenses within the optical system (1000) may have a refractive index greater than 1.6. Accordingly, color dispersion by the lenses within the optical system (1000) may be controlled. The F number of the optical system (1000) may provide a brightness of 2.1 or greater.

[0065] The object-side first surface (S1) of the first lens (101, 111) may have a convex shape toward the object. The convex object-side first surface (S1) may increase the amount of incident light of the first lens group (LG1). The sensor-side surface of the lens in the first lens group (LG1) closest to the first reflective member (P1) may have a concave shape. The sensor-side surface of the first lens group (LG1) may refract the incident light to the entire area of ​​the incident surface (PS1) of the first reflective member (P1). Among the lenses of the second lens group (LG2), the object-side surface of the lens closest to the first reflective member (P1) may have a convex shape. Among the lenses of the second lens group (LG2), the sensor-side surface of the lens closest to the second reflective member (P2) may have a concave shape. The concave sensor-side surface of the second lens group (LG2) can refract incident light to the entire area of ​​the incident surface (PS3) of the second reflective member (P2). Accordingly, the optical system (1000) can increase the amount of incident light, have good optical performance in the center and periphery of the field of view (FOV), and improve thermal compensation, chromatic aberration, and distortion aberration.

[0066] Hereinafter, the object-side surface of the first lens group (LG1) may be defined as the object-side surface or the incident surface of the lens closest to the object among the lenses of the first lens group (LG1), and the sensor-side surface of the first lens group (LG1) may be defined as the sensor-side surface or the output surface of the lens closest to the first reflective member (P1) among the lenses of the first lens group (LG1). The object-side surface of the second lens group (LG2) may be defined as the object-side surface or the incident surface of the lens closest to the first reflective member (P1) among the lenses of the second lens group (LG2), and the sensor-side surface of the second lens group (LG2) may be defined as the sensor-side surface or the output surface of the lens closest to the second reflective member (P2) among the lenses of the second lens group (LG2).

[0067]

[0068] The first lens (101, 111) may be made of a plastic material or a glass material. The first lens (101, 111) may be a spherical or aspherical lens. Lenses other than the first lens (101, 111) may be made of a plastic material or an aspherical lens. Each of the plurality of lenses may include an effective area and an ineffective area. The effective area may be an area through which light incident on each of the lenses passes. That is, the effective area may be an area of ​​an effective diameter or an effective length through which the incident light is refracted to implement optical characteristics. The ineffective area may be arranged around the periphery of the effective area. The end of the effective area may be defined as an edge or an end. The ineffective area may be an area through which effective light is not incident from the plurality of lenses. That is, the ineffective area may be an area unrelated to the optical characteristics. In addition, the end of the ineffective area may be an area fixed to a barrel (not shown) that accommodates the lens.

[0069]

[0070] The optical system (1000) may include an image sensor (190). The image sensor (190) may detect light and convert it into an electrical signal. The image sensor (190) may detect light that has sequentially passed through the plurality of lenses (100). The image sensor (190) may be any one of a CCD (Charge Coupled Device), a CMOS (Complementary Metal Oxide Semiconductor), a CPD, and a CID, and may include an element that can detect incident light. The image sensor (190) may be an RGB (Red, Green, Blue) sensor for obtaining a color image. In addition, when the image sensors (190) are arranged in plurality, the image sensors (190) may include an RGB image sensor and a black and white image sensor. The diagonal length of the image sensor (190) may be greater than 4 mm, for example, greater than 4 mm and less than 12 mm. Preferably, the diagonal length of the image sensor (190) may be longer than the effective length of the lenses arranged between the first and second reflective members (P1, P2).

[0071] The optical system (1000) may include an optical filter (192) disposed between the second reflective member (P2) and the image sensor (190). The optical filter (192) may be disposed between the last lens (107, 116) and the image sensor (190). The optical filter (192) may be disposed between the lens closest to the sensor among the plurality of lenses and the image sensor (190). The optical filter (192) may include at least one of an infrared filter and a cover glass. The optical filter (192) may pass light of a set wavelength band and filter light of a different wavelength band. When the optical filter (192) includes an infrared filter, it may block radiant heat emitted from external light from being transmitted to the image sensor (190). The optical filter (192) may transmit visible light and reflect infrared light. A cover glass (not shown) may be included between the optical filter (192) and the image sensor (190). The cover glass may protect the image sensor (190). The camera module may be a camera for capturing RGB images or a camera for capturing RGB images and infrared images.

[0072]

[0073] The optical system (1000) according to the embodiment may include an aperture stop (ST). The aperture (ST) may be a stopper that adjusts the amount of light incident on the optical system (1000). For example, the aperture (ST) may be arranged around the periphery of the object-side surface of the first lens (101, 111). The aperture (ST) may be arranged around the periphery of the object-side surface of the third lens (103, 113). As another example, the aperture (ST) may be arranged around the periphery of the lens closest to the exit surface (PS2) of the first reflective member (P1).

[0074] The field of view (FOV) of the optical system (1000) may be less than or equal to 60 degrees, for example, more than 10 degrees, for example, in the range of 15 to 60 degrees, and for example, in the range of 15 to 45 degrees. The F number (F#) of the optical system (1000) may be greater than or equal to 2.1, for example, in the range of 2.0 < F# < 5. In addition, the F# may be greater than the entrance pupil size (EPD). Therefore, the optical system (1000) may have a slim size, control incident light, and have improved optical characteristics within the field of view range.

[0075] The second optical axis (OA2) may be positioned within a range of ±5 degrees relative to a straight line orthogonal to the first optical axis (OA1). That is, the second optical axis (OA2) may be within a range of 86 to 95 degrees relative to the first optical axis (OA1). Accordingly, the height in the third direction (Z) between the image sensor (190) and the first reflective member (P1) may be reduced.

[0076]

[0077] Hereinafter, the optical system according to the embodiments will be described in detail. FIGS. 1 to 11 are drawings explaining the optical system of the first embodiment.

[0078] Referring to FIGS. 1 to 4, in the first embodiment of the invention, the optical system (1000) may include first and second lenses (101, 102) arranged from the object toward the sensor, a first reflective member (P1), third to seventh lenses (103-107), and a second reflective member (P2).

[0079] The first and second lenses (101, 102) arranged on the object side of the first reflective member (P1) may be defined as a first lens group (LG1). The third to seventh lenses (103-107) arranged between the first reflective member (P1) and the second reflective member (P2) may be defined as a second lens group (LG2). The number of lenses of the first lens group (LG1) may be 2 to 3. The number of lenses of the second lens group (LG2) may be 3 to 6 or less. The number of lenses of the second lens group (LG2) may be twice or more the number of lenses of the first lens group (LG1), and preferably may be in the range of 2 to 3 times. The optical system (1000) may have 8 or less lenses, for example, 7 lenses.

[0080] The first and second lenses (101, 102) are sequentially arranged along the first optical axis (OA1) between the object and the first reflective member (P1), and the third to seventh lenses (103-107) are sequentially arranged along the second optical axis (OA2) between the first reflective member (P1) and the second reflective member (P2). Each of the first to seventh lenses (101-107) may have an object-side surface and a sensor-side surface. The refractive power of the first lens group (LG1) may have a positive value, and the refractive power of the second lens group (LG2) may have a positive value. The refractive power of the first lens group (LG1) is FLG1, and the refractive power of the second lens group (LG2) is FLG2, and the condition: FLG1 < FLG2 may be satisfied. The first lens group (LG1) is fixed in position according to the operation mode, and the second lens group (LG2) can have a variable position according to the operation mode.

[0081]

[0082] The first lens (101) may have positive (+) or negative (-) refractive power on the first optical axis (OA1), and preferably positive (+) refractive power. The first lens (101) may include plastic. The object-side first surface (S1) of the first lens (101) on the first optical axis (OA1) may have a convex shape, and the sensor-side second surface (S2) may have a concave shape. That is, the first lens (101) may have a convex meniscus shape toward the object on the first optical axis (OA1). Since the first lens (101) has a convex meniscus shape toward the object, the amount of incident light may be improved. At least one or both of the first surface (S1) and the second surface (S2) may be aspherical. The aspherical coefficients of the first surface (S1) and the second surface (S2) are provided as shown in FIG. 4, and L1 represents the first lens (101) and represents the radius of curvature (R), the conic constant (K), and the aspherical coefficients from the 4th to the 12th order. Alternatively, the first lens (101) may have a meniscus shape convex toward the first reflective member (P1). Alternatively, the first lens (101) may have a convex shape on both sides. Alternatively, the first lens (101) may have a concave shape on both sides.

[0083] The effective length (Clear aperture) of the first lens (101) may be the largest among the effective lengths of the first to seventh lenses (101-107). The first surface (S1) of the first lens (101) may be the largest among the lens surfaces (S1-S14) of the first to seventh lenses (101-107). Accordingly, the amount of incident light of the first lens (101) may be improved. The effective length (Clear aperture) of the first lens (101) is the diameter of the effective area and is twice the SA (semi-aperture). The effective length (Clear aperture) of each lens is the average of the effective lengths of the object-side surface and the sensor-side surface of each lens.

[0084]

[0085] The second lens (102) may have positive (+) or negative (-) refractive power on the first optical axis (OA1). The second lens (102) may have negative (-) refractive power. The second lens (102) may correct aberrations occurring in the first lens (101). The second lens (102) may include a plastic or glass material. For example, the second lens (102) may be provided with a plastic material. The object-side third surface (S3) of the second lens (102) on the first optical axis (OA1) may have a convex shape, and the sensor-side fourth surface (S4) may have a concave shape. That is, the second lens (102) may have a convex meniscus shape toward the object on the second optical axis (OA). In contrast, the third surface (S3) may have a convex shape on the second optical axis (OA2), and the fourth surface (S4) may have a convex shape. In contrast, the second lens (102) may have a concave shape on both sides or a meniscus shape convex toward the first reflective member (P1). At least one or both of the third surface (S3) and the fourth surface (S4) of the second lens (102) may be aspherical. The aspherical coefficients of the third surface (S3) and the fourth surface (S4) of the second lens (102) are provided as shown in FIG. 4, and L2 represents the second lens (102) and represents the Conic constant (K) and aspherical coefficients from the 4th to the 6th order.

[0086] The center distance between the first lens (101) and the second lens (102) can be set to 1 mm or less, for example, 0.5 mm or less, thereby reducing the loss of light passing through the first and second lenses (101, 102) and suppressing an increase in the optical axis distance (TD1) of the first lens group (LG1). The center thickness (CT2) of the second lens (102) can be the thinnest among the lenses in the first lens group (LG1).

[0087]

[0088] The first reflective member (P1) is disposed between the second lens (102) and the third lens (103). The first reflective member (P1) is disposed between the fourth surface (S4) of the second lens (102) and the fifth surface (S5) of the third lens (103). The first reflective member (P1) reflects or refracts light incident on the first optical axis (OA1) toward the second optical axis (OA2). The first reflective member (P1) has a triangular prism shape and may be provided with a glass material or a plastic material. The first reflective member (P1) includes an incident surface (PS1), a reflective surface (PR1), and an exit surface (PS2), wherein the incident surface (PS1) faces the second lens (102), and the exit surface (PS2) faces the third lens (103). The center distance (MG1) between the incident surface (PS1) of the first reflective member (P1) and the second lens (102) may be 0.5 mm or more, for example, 1 mm or more. The shape of the sensor-side surface (S4) of the second lens (102) may have a concave shape.

[0089] The effective length of the second lens (112) may be arranged to be 85% or more, for example, in the range of 85% to 99%, of the effective length of the first lens (111). Since the center distance (MG1) between the second lens (112) and the first reflective member (P1) is 0.5 mm or more, the second lens (112) can transmit light passing through the first lens (111) having a large effective length to the incident surface (PS1) of the first reflective member (P1) without loss.

[0090]

[0091] The third lens (103) may have positive (+) or negative (-) refractive power on the second optical axis (OA2), and preferably positive (+) refractive power. The third lens (103) may include a plastic or glass material. The object-side fifth surface (S5) of the third lens (103) on the second optical axis (OA2) may have a convex shape, and the sensor-side sixth surface (S6) may have a convex shape. That is, the third lens (103) may have a convex shape on both sides on the second optical axis (OA2). Alternatively, the third lens (103) may have a convex meniscus shape toward the first reflective member (P1). Alternatively, the third lens (103) may have a convex meniscus shape toward the second reflective member (P2). At least one or both of the fifth surface (S5) and the sixth surface (S6) of the third lens (103) may be aspherical. The aspherical coefficients of the fifth and sixth surfaces (S5, S6) are provided as shown in FIG. 4, and L3 represents the third lens (103) and represents the conic constant (K) and aspherical coefficients from the 4th to the 14th order.

[0092]

[0093] As shown in FIGS. 1 and 2, the center distance (D1) between the first reflective member (P1) and the third lens (103) can be varied by the second lens group (LG2). The second lens group (LG2) can be moved from the first mode (Md1) to the second mode (Md1) or from the second mode (Md1) to the first mode (Md1). The first mode (Md1) is an infinity mode, and the second mode (Md2) is a close-range mode, such as a 50 cm shooting mode. The second mode (Md2) can be a focusing mode.

[0094] In the infinity mode, the center distance (D1) between the first reflective member (P1) and the third lens (103) may be greater than the center thickness (CT2) of the second lens (102) and may be less than the center thickness (CT1) of the first lens (101). In the near mode, the center distance (D1) between the first reflective member (P1) and the third lens (103) may be less than the distance in the infinity mode, may be less than the center thickness (CT1) of the first lens (101) and may be greater than the center thickness (CT2) of the second lens (102).

[0095]

[0096] The fourth lens (104) may have positive (+) or negative (-) refractive power on the second optical axis (OA2). The fourth lens (104) may have negative (-) refractive power. The fourth lens (104) may include a plastic or glass material. For example, the fourth lens (104) may be provided with a plastic material. Since the signs of the refractive powers of the third and fourth lenses (103, 104) are opposite to each other, chromatic aberrations occurring in the two lenses can be mutually compensated.

[0097] The object-side seventh surface (S7) of the fourth lens (104) on the second optical axis (OA2) may have a concave shape, and the sensor-side eighth surface (S8) may have a concave shape. That is, the fourth lens (104) may have a concave shape on both sides on the second optical axis (OA2). Alternatively, the fourth lens (104) may have a convex meniscus shape toward the second reflective member (P2). Alternatively, the fourth lens (104) may have a convex shape on both sides. Alternatively, the fourth lens (104) may have a convex meniscus shape toward the first reflective member (P1). At least one or both of the seventh surface (S7) and the eighth surface (S8) may be aspherical, and the conic constant (K) and aspherical coefficients from the fourth to the twelfth order are provided as shown in FIG. 4, and L4 is the fourth lens (104).

[0098]

[0099] The fifth lens (105) may have positive (+) or negative (-) refractive power on the second optical axis (OA2). The fifth lens (105) is the n-2th lens and may have negative 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. The refractive power of the fifth lens (105) may be the largest among the absolute values ​​of the refractive powers of the first to seventh lenses (101-107).

[0100] On the second optical axis (OA2), the object-side ninth surface (S9) of the fifth lens (105) may have a convex shape, and the sensor-side tenth surface (S10) may have a concave shape. That is, the fifth lens (105) may have a convex meniscus shape toward the first reflective member (P1) or the object on the second optical axis (OA2). Alternatively, the fifth lens (105) may have a convex meniscus shape toward the second reflective member (P2) or the sensor. Alternatively, the fifth lens (105) may have a convex shape on both sides. Alternatively, the fifth lens (105) may have a concave shape on both sides. At least one or both of the ninth surface (S9) and the tenth surface (S10) of the fifth lens (105) may be aspherical, and the aspherical coefficient is provided as in FIG. 4, and L5 is the fifth lens (105).

[0101]

[0102] The sixth lens (106) may have positive (+) or negative (-) refractive power on the optical axis (OA). The sixth lens (106), as the n-1th lens, may have refractive power of the opposite sign to that of the n-2nd lens, for example, 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. Since the signs of the refractive powers of the fifth and sixth lenses (105 and 106) are opposite to each other, chromatic aberrations occurring in the two lenses may be mutually compensated.

[0103] On the second optical axis (OA2), the object-side eleventh surface (S11) of the sixth lens (106) may have a convex shape, and the sensor-side twelfth surface (S12) may have a concave shape. That is, the sixth lens (106) may have a convex meniscus shape toward the first reflective member (P1) or the object on the second optical axis (OA2). Alternatively, the sixth lens (106) may have a convex meniscus shape toward the sensor or the second reflective member (P2). Alternatively, the sixth lens (106) may have a concave or convex shape on both sides. At least one or both of the eleventh surface (S11) and the twelfth surface (S12) may be aspherical, and aspherical coefficients from the fourth to the sixth are provided as shown in FIG. 4, and L6 is the sixth lens (106).

[0104] Since the 12th surface (S12) of the sixth lens (106) has a concave shape on the second optical axis (OA2), the center distance between the sixth lens (106) and the seventh lens (107) can be increased, and the sixth lens (106) can irradiate light to the entire area of ​​the seventh lens (107). The sixth lens (106) is the n-1th lens and can have the minimum effective length among the effective lengths of the first to seventh lenses (101-107). For example, the effective length of the 12th surface (S10) of the sixth lens (106) can be the smallest among the lens surfaces. The maximum effective length of the lenses can be more than 1 time, for example, more than 1 time and less than 3 times, the minimum effective length. The first surface (S1) of the first lens (101) may be at least 1.5 times, for example, in the range of 1.5 to 2.5 times, the effective length of the twelfth surface (S12) of the sixth lens (106).

[0105]

[0106] The seventh lens (107) may have positive (+) or negative (-) refractive power on the optical axis (OA). The seventh lens (107), as the nth lens, may have refractive power of the opposite sign to that of the (n-1)th lens, for example, 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. Since the signs of the refractive powers of the sixth and seventh lenses (106, 107) are opposite to each other, chromatic aberrations occurring in the two lenses can be mutually compensated.

[0107] On the second optical axis (OA2), the object-side 13th surface (S13) of the seventh lens (107) may have a convex shape, and the sensor-side 14th surface (S14) may have a concave shape. That is, the seventh lens (107) may have a convex meniscus shape toward the first reflective member (P1) or the object on the second optical axis (OA2). Alternatively, the seventh lens (107) may have a convex meniscus shape toward the second reflective member (P2) or the sensor. Alternatively, the seventh lens (107) may have a convex or concave shape on both sides. At least one or both of the 13th surface (S13) and the 14th surface (S14) may be aspherical, and aspherical coefficients from the 4th to the 16th are provided as shown in FIG. 4, and L7 is the 7th lens (107).

[0108] Since the difference in the radius of curvature between the 13th surface (S13) and the 14th surface (14) of the seventh lens (107) is provided to be less than 2 times, the seventh lens (107) can refract the incident light to the entire area of ​​the second reflective member (P2). Accordingly, the light reflected through the second reflective member (P2) can be irradiated to the center and periphery of the image sensor (190). Therefore, the optical system (1000) according to the embodiment can have improved optical characteristics even in the center and periphery of the field of view (FOV).

[0109] The fifth lens (105) is the n-2th lens, has a positive refractive power, and may have the largest absolute value among the first to seventh lenses (101-107). The absolute value of the refractive power of the fifth lens (105) may be greater than the sum of the absolute values ​​of the refractive powers of the first to second lenses (101, 102).

[0110]

[0111] In the second optical axis direction, the distance (D1) between the exit surface (PS2) of the first reflective member (P1) and the third lens (104) and the distance (D2) between the last lens (107) and the second reflective member (P2) can be varied by the movement of the second lens group (LG2) according to the operating mode. The second lens group (LG2) can move from the first mode (Md1) of infinity, as shown in FIG. 1, to the second mode of short distance, as shown in FIG. 2. In the first mode, the first distance (D1) between the first reflective member (P1) and the second lens group (LG2) in the second optical axis direction can be smaller than the second distance (D2) between the second reflective member (P2) and the second lens group (LG2). In the second mode (Md2), the first distance (D1) between the first reflective member (P1) and the second lens group (LG2) in the second optical axis direction may be smaller than the second distance (D2) between the second reflective member (P2) and the second lens group (LG2). Since the first distance (D1) is emitted through the first reflective member (P1) without power, the distance (D1) between the first reflective member (P1) and the third lens (103) may be at least 1.5 mm or less.

[0112]

[0113] The second reflective member (P2) has an incident surface (PS3), a reflective surface (PR2), and an exit surface (PS4), and the reflective surface (PR2) can be inclined at an angle of 45 degrees with respect to the second optical axis (OA2). In the lens data of FIG. 3, CT is the central thickness of the lens and the reflective member, CG represents the central spacing between adjacent lenses, or the central spacing between the reflective member and the lens, and represents CT / CG in the infinity mode (Md1) and CT / CG in the near mode (Md2), i.e., the 50 cm mode. In addition, the semi-aperture is half the length of the effective area of ​​the lens, FL represents the focal length of each lens, Nd is the refractive index at the d-line, and Ad is the Abbe number of each lens. PS1 is the incident surface of the first reflective member, PS2 is the exit surface of the first reflective member, PS3 is the incident surface of the second reflective member, PS4 is the exit surface of the second reflective member, FS1 is the object-side surface of the filter, and FS2 is the sensor-side surface of the filter.

[0114] The light reflected through the second reflective member (P2) is incident on the entire area of ​​the image sensor (190) through the optical filter (192). The central axis passing through the optical filter (192) and the image sensor (190) may be parallel to the first optical axis (OA1). The optical filter (192) and the image sensor (190) are positioned at a position further away from the object with respect to the second optical axis (OA2).

[0115]

[0116] The center thickness and edge thickness of the above lenses are as follows. The center thickness of the first to seventh lenses (101-107) is CT1-CT7, the edge thickness is ET1-ET7, the optical axis distance between the image sensor (190) and the sensor-side surface (S12) of the last lens (106) is BFL (Back focal length), and at least one of the following conditions may be satisfied. Here, the edge thickness of each lens may be the distance in the optical axis direction between the effective areas of each lens.

[0117] Condition 1: CT2 < CT1

[0118] Condition 2: CT2 < ET2 < CT1

[0119] Condition 3: 1 mm < CT3 < CT1 < 2.5 mm

[0120] Condition 4: 0.5 < CT5 / ET5 < 1.5

[0121] Condition 5: 0.5 < CT6 / ET6 < 1.5

[0122] Condition 6: 0.5 < CT7 / ET7 < 1.5

[0123] Condition 7: CT4 < ET4

[0124] Condition 8: (CT4 + CT5 + CT6 + CT7) < BFL

[0125]

[0126] The optical axis distance from the first surface (S1) of the first lens (101) to the fourth surface (S4) of the second lens (102) is the first optical axis distance (TD1) of the first lens group (LG1), and the optical axis distance from the fifth surface (S5) of the third lens (103) to the fourteenth surface (S14) of the seventh lens (106) is the second optical axis distance (TD2) of the second lens group (LG2), and the condition: TD1 < TD2 can be satisfied. Accordingly, the optical system (1000) can control incident light and have improved aberration characteristics and resolution.

[0127] The center thickness (CT4-CT7) of each of the above 4-7 lenses (104-107) may be thinner than the thicknesses of the other lenses, and may be 0.8 mm or less. Since the second lens group (LG2) includes lenses having a thin thickness, power consumption due to movement may be reduced. The smallest value among D1 and D2 in the operating mode is D2_50, and D2_50 is the D2 value in the near mode, and may satisfy the following conditions. D1_50 is the D1 value in the infinity mode, and D1_Inf is the D1 value in the infinity mode.

[0128] Condition 1: D1_50 < MG1

[0129] Condition 2: D1_50 < CT3

[0130] Condition 3: CT3 < D1_Inf

[0131] Condition 4: CT7 < D1_50

[0132] MG1 is the center distance between the second lens (102) and the first reflective member (P1).

[0133] The second lens group (LG2) can be moved according to the operation mode, and can be moved within a range of 0.5 mm or more, for example, 0.5 mm to 4.0 mm. Since the second lens group (LG2) is moved, objects from a long distance (e.g., infinity) to a close distance (e.g., 50 cm) can be captured.

[0134]

[0135] The radii of curvature of the above lenses are as follows.

[0136] On the first and second optical axes (OA1, OA2), the radius of curvature of the first and second surfaces (S1, S2) of the first lens (101) is L1R1, L1R2, the radius of curvature of the third and fourth surfaces (S3, S4) of the second lens (102) is L2R1, L2R2, the radius of curvature of the fifth and sixth surfaces (S5, S6) of the third lens (103) is L3R1, L3R2, the radius of curvature of the seventh and eighth surfaces (S7, S8) of the fourth lens (104) is L4R1, L4R2, the radius of curvature of the ninth and tenth surfaces (S9, S10) of the fifth lens (105) is L5R1, L5R2, and the radius of curvature of the eleventh and twelfth surfaces (S11, S12) of the sixth lens (106) is The radii of curvature of the 13th and 14th surfaces (S13, S14) of the seventh lens (107) are L6R1 and L6R2, and the radii of curvature of the 13th and 14th surfaces (S13, S14) of the seventh lens (107) can be defined as L7R1 and L7R2. The radii of curvature can satisfy at least one of the following conditions for improving the aberration characteristics of the optical system.

[0137] Condition 1: L1R1 < L1R2

[0138] Condition 2: L2R2 < L1R1 < L2R1 < L1R2

[0139] Condition 3: L2R2 < |L3R2| < L5R1

[0140] Condition 4: |L4R2| < |L4R1| < L1R2

[0141] Condition 5: 0.5 < |L6R1 / L6R2|< 1.5

[0142] Condition 6: 0.5 < |L6R1 / L6R2|< 1.5

[0143] Condition 7: 1 < L5R1 / L5R2 < 3

[0144] In the absolute values ​​of the radius of curvature of each lens surface, the ninth surface (S9) of the fifth lens (105) may be the largest among the lens surfaces, and the fourteenth surface (S14) of the seventh lens (107) may be the smallest among the lens surfaces. By setting the radius of curvature of each lens, good optical performance can be provided at the focal length of each lens.

[0145]

[0146] The effective lengths of the first to seventh lenses (101-107) may be defined as CA1-CA7, and the effective length (CA1) of the first lens (101) may have the maximum effective length among the lenses and may be 5.5 mm or more. The effective length (CA6) of the sixth lens (106) may be the minimum among the lenses. The average of the effective lengths of the lenses of the first lens group (LG1) may be greater than the average of the effective lengths of the lenses of the second lens group (LG2).

[0147] The effective length of the first and second surfaces (S1, S2) of the first lens (101) can be defined as CA11, CA12, the effective length of the third and fourth surfaces (S3, S4) of the second lens (102) can be defined as CA21, CA22, the effective length of the fifth and sixth surfaces (S5, S6) of the third lens (103) can be defined as CA31, CA32, the effective length of the seventh and eighth surfaces (S7, S8) of the fourth lens (104) can be defined as CA41, CA42, the effective length of the ninth and tenth surfaces (S9, S10) of the fifth lens (105) can be defined as CA51, CA52, the effective length of the eleventh and twelfth surfaces (S11, S12) of the sixth lens (106) can be defined as CA61, CA62, and the seventh The effective lengths of the 13th and 14th surfaces (S13, S14) of the lens (107) can be defined as CA71 and CA72. These effective lengths are factors that affect the aberration characteristics of the optical system, and can satisfy at least one of the following conditions.

[0148] Condition 1: CA4 < CA3 < CA2 < CA1

[0149] Condition 2: (CA2-CA1) < (CA2-CA3)

[0150] Condition 3: CA6 < CA5 < CA7

[0151] Condition 3: 3mm < CA32 < CA21 < CA11 < 10mm

[0152] Condition 4: 3mm < CA5, CA6, CA7 < 5mm

[0153] The effective length (CA11) of the first surface (S1) of the first lens (101) is provided as the largest within the optical system, thereby increasing the amount of incident light. Accordingly, the difference between the effective length of the sensor-side surface (S12) of the fifth lens (106) and the maximum effective length can be set to 2 mm or more.

[0154] Among the first to seventh lenses (101-107), the number of lenses having an effective length smaller than the diagonal length of the image sensor (190) may be two or less, for example, the sixth lens.

[0155]

[0156] The number of lenses having a refractive index exceeding 1.6 of the above lenses may be two or less. Among the plastic lenses in the above lenses, the second lens (102) has a refractive index exceeding 1.60 and can refract the incident light to the entire area of ​​the first reflective member (P1). In the optical system, the number of lenses having an Abbe number exceeding 45 may be two or more, and may be, for example, the first, third, and seventh lenses (101, 103, and 107). By setting the refractive index and Abbe number of each of these lenses, the influence of chromatic aberration can be controlled. Depending on the refractive index and Abbe number, the optical system (1000) may have improved chromatic aberration control characteristics.

[0157]

[0158] The effective focal length of the optical system (1000) is F, and when the focal length of each lens (101-106) is defined as F1-F7, the following conditions can be satisfied.

[0159] Condition 1: F1 < |F2|

[0160] Condition 2: F3 < |F2|

[0161] Condition 3: |F4| < F5

[0162] Condition 4: F1 < F6 < |F7|< |F5|

[0163] Condition 5: F3 < F < |F2|

[0164] Among the absolute values ​​of the focal lengths of the lenses, the largest lens is the fifth lens (105), which may be 40 mm or more. Among the absolute values ​​of the focal lengths of the lenses, the smallest lens is the third lens (103).

[0165]

[0166] In FIG. 1, the height of the optical system (1000) is the sum of the first optical axis distance (T1) from the center of the object-side surface (S1) of the first lens (101) to the center of the reflective surface (PR1) of the first reflective member (P1), and the optical axis distance (T3) from the center of the reflective surface (PR2) of the second reflective member (P2) to the center of the upper surface of the image sensor (190), and the condition: T3 < T1 can be satisfied.

[0167] The second optical axis distance (T2) from the center of the reflective surface (PR1) of the first reflective member (P1) to the center of the reflective surface (PR2) of the second reflective member (P2) can affect the length of the first direction (X) of the optical system (1000). The total length (TTL) of the optical system (1000) is the length of the first and second optical axes (OA1, OA2) from the center of the object-side surface (S1) of the first lens (101) to the image sensor (190), and is the sum of the first to third optical axis distances (T1, T2, T3), and can satisfy the condition: T1 < T2. In addition, the condition: 1 < T2 / (T1+T3) < 3 can be satisfied. Since the image sensor (190) is arranged parallel to the first direction (X), the image sensor (190) and the first reflective member (P1) may not overlap in the first direction (X). The distance between the first and second reflective members (P1, P2) is D3, and the condition: T1 < D3 < T2 may be satisfied.

[0168]

[0169] As shown in Fig. 5, the inclination angle (R1) of the reflective surface (PR1) of the first reflective member (P1) may be less than 45 degrees, for example, in the range of 40 degrees to 44 degrees, with respect to an axis perpendicular to the first optical axis (OA1). That is, the second optical axis (OA2) may be less than 90 degrees with respect to the first optical axis (OA1). Accordingly, the lenses of the second lens group (LG2) arranged along the second optical axis (OA2) are spaced apart from the object side relative to the axis (X1), and the optical filter (192) and the image sensor (190) are not parallel to the axis perpendicular to the first optical axis (OA1) and may overlap with the first reflective member (P1) in the first direction (X).

[0170] As shown in Fig. 6, the second reflective member (P2) can reflect incident light toward the object. Accordingly, the optical filter (192) and the image sensor (190) can be positioned closer to the object than the second reflective member (P2). Since the optical filter (192) and the image sensor (190) are positioned in the object-side direction of the second reflective member (P2), the height of the optical system in the third direction (Z) can be reduced.

[0171]

[0172] The invention can move the first lens group (LG1) in the direction of the second optical axis (OA) for OIS driving. For example, as shown in (A)(B) of Fig. 7, the first optical axis (OA1) passing through the first and second lenses (101, 102) of the first lens group (LG1) can move toward one end (Pz1) of the incident surface (PS1) of the first reflective member (P1), or the first optical axis (OA1) can move toward the other end (Pz2) of the incident surface (PS1) of the first reflective member (P1). By means of (A)(B) of Fig. 7, the lenses of the first lens group (LG1) can move in the direction of the second optical axis (OA), and in this case, the first lens group (LG1) can be connected to a driving unit such as an actuator. In addition, as shown in (A)(B) of FIG. 7, a part of the effective area of ​​at least one of the first and second lenses (101, 102) may not overlap in the third direction (Z), i.e., an area outside one end (Pz1) or the other end (Pz2) of the incident surface (PS1) of the first reflective member (P1).

[0173]

[0174] Figures 8 (A) and (B) are graphs showing the diffraction MTF (Modulation Transfer Function) in the infinity mode and near-field mode in the optical system of Figures 1 and 2, and are graphs showing the luminance ratio (modulation) according to the spatial frequency.

[0175] FIG. 9 is a graph showing the aberration characteristics in the infinity mode of the optical system of FIG. 1 and FIG. 2, and FIG. 10 is a graph showing the aberration characteristics in the near mode of the optical system of FIG. 1. Referring to FIG. 9 and FIG. 10, graphs showing spherical aberration, astigmatic field curves, and distortion are measured from left to right in the aberration graphs of the optical system. The X-axis may represent the focal length (mm) and the degree of distortion (%), and the Y-axis may represent the height of the image. In addition, the graph for spherical aberration is a graph for light in wavelength bands of about 470 nm, about 555 nm, about 610 nm, and about 650 nm, and the graphs for astigmatism and distortion are graphs for light in wavelength bands of 555 nm.

[0176] As shown in Fig. 11, this is a graph showing relative illumination according to the relative sensor height (relative Fielded height) in the first and second modes of the optical systems of Figs. 1 and 2. As shown in Fig. 11, it can be seen that the relative illumination is highest in the center (0.0) field (Field) of the image sensor and is 40% or more to the end (1.0) field.

[0177] The optical system (1000) according to the first embodiment has improved resolution and can exhibit good optical performance not only at the center but also at the periphery of the field of view (FOV). The lens system according to the first embodiment of the present invention can effectively correct spherical aberration, astigmatism, distortion, chromatic aberration, and coma aberration with a configuration of seven or fewer lenses.

[0178]

[0179] Figures 12 to 22 are drawings illustrating a second embodiment. In describing the second embodiment, the same configuration as the first embodiment may include the configuration and description of the first embodiment.

[0180] Referring to FIGS. 12 to 16, an optical system (1000) according to a second embodiment of the invention may include first and second lenses (111, 112), a first reflective member (P1), third to sixth lenses (113-116), and a second reflective member (P2) arranged from an object toward a sensor.

[0181] The first and second lenses (111, 112) are a first lens group (LG1), and the third to sixth lenses (113-116) are a second lens group (LG2). The number of lenses of the first lens group (LG1) may be more than 1 and less than or equal to 3. The number of lenses of the second lens group (LG2) may be more than or equal to the number of lenses of the first lens group (LG1), for example, 1.5 times or more. The number of lenses of the first and second lens groups (LG1, LG2) may be different from each other. The optical system (1000) may have 7 or less lenses, for example, 6 lenses.

[0182] The refractive power of the first lens group (LG1) may have a positive value, and the refractive power of the second lens group (LG2) may have a positive value. The refractive power of the first lens group (LG1) is FLG1, and the refractive power of the second lens group (LG2) is FLG2, and the condition: FLG2 < FLG1 may be satisfied. The position of the first lens group (LG1) may be fixed depending on the operation mode, and the position of the second lens group (LG2) may be variable depending on the operation mode.

[0183] The first, third, and fifth lenses (111, 113, and 115) may have positive refractive power, and the second, fourth, and sixth lenses (112, 114, and 116) may have negative refractive power. The first surface (S1) to the twelfth surface (S12) of the first to sixth lenses (111-116) may be aspherical on the optical axis, and the aspherical coefficient may be expressed as in FIG. 15.

[0184]

[0185] On the first optical axis (OA1), the object-side first surface (S1) of the first lens (111) may have a convex shape, and the sensor-side second surface (S2) may have a concave shape. Since the object-side surface (S1) of the first lens (111) has a convex shape toward the object, the amount of incident light can be improved. The effective length (Clear aperture) of the first lens (111) may be the largest among the effective lengths of the first to sixth lenses (111-116). The first surface (S1) of the first lens (111) may be the largest among the lens surfaces (S1-S12) of the first to sixth lenses (111-116). Accordingly, the amount of incident light of the first lens (111) can be improved.

[0186] On the first optical axis (OA1), the object-side third surface (S3) of the second lens (112) may have a convex shape, and the sensor-side fourth surface (S4) may have a concave shape. The effective length of the second lens (112) may be arranged to be 85% or more, for example, in the range of 85% to 95%, of the effective length of the first lens (111). Since the center distance (MG1) between the second lens (112) and the first reflective member (P1) is 0.5 mm or more, the second lens (112) can transmit light passing through the first lens (111) having a large effective length to the incident surface (PS1) of the first reflective member (P1) without loss.

[0187] The optical axis distance (TD1) of the first lens group (LG1) is the optical axis distance from the center of the first surface (S1) of the first lens (111) to the center of the fourth surface (S4) of the second lens (112), and the center thicknesses (CT1, CT2) of the first and second lenses (111, 112) can satisfy the condition: CT2 < CT1 < MG1.

[0188] The second lens (112) has a refractive power whose sign is opposite to that of the first lens (111), and thus can correct aberrations occurring in the first lens (111). The third lens (113) has a refractive power whose sign is opposite to that of the second lens (112), and thus can correct aberrations occurring in the second lens (112). The fifth lens (115) has a refractive power whose sign is opposite to that of the fourth lens (114), and thus can correct aberrations occurring in the fourth lens (114).

[0189]

[0190] On the second optical axis (OA1), the object-side fifth surface (S5) of the third lens (113) may have a convex shape, and the sensor-side sixth surface (S6) may have a convex shape. On the second optical axis (OA1), the object-side seventh surface (S7) of the fourth lens (114) may have a concave shape, and the sensor-side eighth surface (S8) may have a concave shape. On the second optical axis (OA1), the object-side ninth surface (S9) of the fifth lens (115) may have a convex shape, and the sensor-side tenth surface (S10) may have a concave shape. On the second optical axis (OA1), the object-side eleventh surface (S11) of the sixth lens (116) may have a convex shape, and the sensor-side twelfth surface (S12) may have a concave shape.

[0191]

[0192] The first reflective member (P1) is disposed between the second lens (112) and the third lens (113). The first reflective member (P1) is disposed between the fourth surface (S4) of the second lens (112) and the fifth surface (S5) of the third lens (113). The first reflective member (P1) reflects or refracts light incident on the first optical axis (OA1) toward the second optical axis (OA2). The incident surface (PS1) of the first reflective member (P1) faces the second lens (112), and the exit surface (PS2) faces the third lens (113). The center distance (D1) between the exit surface (PS2) of the first reflective member (P1) and the third lens (113) varies depending on the movement of the second lens group (LG2), and may be 0.5 mm or more.

[0193] The second lens group (LG2) can be moved from infinity to a near mode, and the near mode can be 50 cm. When infinity, the center distance (D1) between the first reflective member (P1) and the third lens (113) can be greater than the center thickness (CT3) of the third lens (113) and can be greater than the center thickness (CT1) of the first lens (111). When in the near focusing mode, the center distance (D1) between the first reflective member (P1) and the third lens (113) can be smaller than the distance in the infinity mode and can be smaller than the center thickness (CT1) of the first lens (111).

[0194]

[0195] The fifth lens (115) is the n-1th lens and may have the minimum effective length among the effective lengths of the first to sixth lenses (111-116). For example, the effective length of any one of the ninth and tenth surfaces (S9, S10) of the fifth lens (115) may be the smallest among the lens surfaces. The maximum effective length of the lenses may be more than 1 time, for example, more than 1 time and less than 3 times, the minimum effective length.

[0196] Since the twelfth surface (S12) of the sixth lens (136) has a concave shape, the sixth lens (116) can irradiate light to the entire area of ​​the incident surface (PS3) of the second reflective member (P2). Accordingly, the light reflected through the second reflective member (P2) can be irradiated to the center and periphery of the image sensor (190). Therefore, the optical system (1000) according to the embodiment can have improved optical characteristics even in the center and periphery of the field of view (FOV).

[0197]

[0198] The reflective surface (PR2) of the second reflective member (P2) can be inclined at an angle of 45 degrees with respect to the second optical axis (OA2). In the lens data of Fig. 14, CT is the central thickness of the lens and the reflective member, CG represents the central spacing between adjacent lenses, or the central spacing between the reflective member and the lens, and represents CT / CG in the infinity mode and CT / CG in the near-distance mode, i.e., the 50 cm mode. In addition, the semi-aperture is 1 / 2 of the length of the effective area of ​​the lens, FL represents the focal length of each lens, Nd is the refractive index at the d-line, and Ad is the Abbe number of each lens and the reflective member.

[0199] The distance (D1) between the exit surface (PS2) of the first reflective member (P1) and the third lens (113) and the distance (D2) between the last lens (116) and the second reflective member (P2) can be varied according to the movement of the second lens group (LG2). In infinity mode, the condition: D1 < D2 is satisfied, and in short-distance mode, the condition: D1 < D2 can be satisfied.

[0200]

[0201] The light reflected through the second reflective member (P2) is incident on the entire area of ​​the image sensor (190) through the optical filter (192). The central axis passing through the optical filter (192) and the image sensor (190) may be parallel to the first optical axis (OA1). The optical filter (192) and the image sensor (190) are positioned at a position further away from the object with respect to the second optical axis (OA2).

[0202] The center thickness, edge thickness, and BFL (Back focal length) of the above lenses can satisfy at least one of the following conditions.

[0203] Condition 1: CT2 < ET2 < CT1

[0204] Condition 2: ET3 < ET1 < CT3

[0205] Condition 3: 0.5 < CT5 / ET5 < 1.5

[0206] Condition 4: 0.5 < CT6 / ET6 < 1.5

[0207] Condition 5: 1 < ET4 / CT4 < 2

[0208] Condition 6: CT4, CT6 < 1mm

[0209] Condition 6: (CT3 + CT4 + CT5 + CT6) < BFL

[0210]

[0211] The optical axis distance from the first surface (S1) of the first lens (111) to the fourth surface (S4) of the second lens (112) is the first optical axis distance (TD1) of the first lens group (LG1), and the optical axis distance from the fifth surface (S5) of the third lens (113) to the twelfth surface (S12) of the sixth lens (116) is the second optical axis distance (TD2) of the second lens group (LG2), and the condition: TD1 < TD2 can be satisfied. Accordingly, the optical system (1000) can control incident light and have improved aberration characteristics and resolution.

[0212] The second lens group (LG2) can reduce power consumption due to movement since the center thickness of the fourth and sixth lenses (114, 116) is less than 1 mm. The smallest value of D1 and D2 in the infinity mode is D1_50, and D1_50 is the D1 value in the near distance mode, and can satisfy the following conditions. D2_50 is the D2 value in the near distance mode, and D2_Inf is the D2 value in the infinity mode.

[0213] Condition 1: D1_50 < MG1

[0214] Condition 2: D1_50 < D2_Inf < D2_50

[0215] Condition 3: CT6 < D1_50 < CT1

[0216] The center spacing (D1, D2) can be varied by moving the second lens group (LG2), and can be moved by a distance of 0.2 mm or more, for example, a range of 0.2 mm to 4 mm. Since the second lens group (LG2) is moved, objects from a long distance (e.g., infinity) to a close distance (e.g., 50 cm) can be imaged.

[0217]

[0218] The radius of curvature of the above lenses can satisfy at least one of the following conditions to improve the aberration characteristics of the optical system.

[0219] Condition 1: L1R1 < L1R2

[0220] Condition 2: L1R1 < L2R2 < L2R1

[0221] Condition 3: |L3R1| < |L4R1| < |L4R2|

[0222] Condition 8: L6R1 < |L5R2| < |L3R2|

[0223] In the absolute values ​​of the radius of curvature of each lens surface, the third surface (S3) of the second lens (112) may be the maximum, and the twelfth surface (S12) of the sixth lens (116) may be the minimum among the lens surfaces. By setting the radius of curvature of each lens, good optical performance can be provided at the focal length of each lens.

[0224]

[0225] The effective lengths of the first to sixth lenses (111-116) may be defined as CA1-CA6, and the effective length (CA1) of the first lens (111) may have the maximum effective length among the lenses and may be 5.5 mm or more. The effective length (CA5) of the fifth lens (115) may be the minimum among the lenses. The average of the effective lengths of the lenses of the first lens group (LG1) may be greater than the average of the effective lengths of the lenses of the second lens group (LG2). These effective lengths are factors that affect the aberration characteristics of the optical system and may satisfy at least one of the following conditions.

[0226] Condition 1: CA6 < CA3 < CA2 < CA1

[0227] Condition 2: CA5 < CA4 < CA3

[0228] Condition 3: CA32 < CA21 < CA11

[0229] Condition 4: CA52 < CA42 < CA62

[0230] The effective length (CA11) of the first surface (S1) of the first lens (111) is provided as the largest within the optical system, thereby increasing the amount of incident light. Accordingly, the difference between the effective length of the sensor-side surface (S10) of the fifth lens (115) and the maximum effective length can be set to 2 mm or more.

[0231] Among the first to sixth lenses (111-116), the number of lenses having an effective length smaller than the diagonal length of the image sensor (190) may be three or more, for example, four or more. For example, the effective lengths of the second to sixth lenses (112-116) may be smaller than the diagonal length of the image sensor (190). The effective lengths of the first to sixth lenses (111-116) may be smaller than the diagonal length of the image sensor (190). For example, the effective lengths of the first to twelfth surfaces (S1-S12) may be smaller than the effective diagonal length of the image sensor (190).

[0232]

[0233] The number of lenses having a refractive index exceeding 1.6 of the above lenses may be 2 or less, and may be the second lens. Within the optical system, lenses having an Abbe number exceeding 45 may be the first and third lenses (111, 113). By setting the refractive index and Abbe number of each of these lenses, the influence of chromatic aberration can be controlled. Depending on the refractive index and Abbe number, the optical system (1000) may have improved chromatic aberration control characteristics.

[0234]

[0235] The focal length (F) of the optical system and the focal lengths of each lens (111-116) F1, F2, F3, F4, F5 can satisfy the following conditions.

[0236] Condition 1: F1 < |F2|

[0237] Condition 2: F3 < |F2|

[0238] Condition 3: |F4| < F5 < |F6|

[0239] Condition 4: F1 < F < |F2|

[0240] Among the absolute values ​​of the focal lengths of the lenses, the largest lens is the sixth lens (116), which may be 20 mm or more. Among the absolute values ​​of the focal lengths of the lenses, the smallest lens is the fourth lens (114).

[0241]

[0242] In FIG. 12, the height of the optical system (1000) is the sum of the first optical axis distance (T1) from the center of the object-side surface (S1) of the first lens (111) to the center of the reflective surface (PR1) of the first reflective member (P1), and the optical axis distance (T3) from the center of the reflective surface (PR2) of the second reflective member (P2) to the center of the upper surface of the image sensor (190), and the condition: T3 < T1 can be satisfied.

[0243] The second optical axis distance (T2) from the center of the reflective surface (PR1) of the first reflective member (P1) to the center of the reflective surface (PR2) of the second reflective member (P2) can affect the length of the first direction (X) of the optical system (1000). The total length (TTL) of the optical system (1000) is the length of the first and second optical axes (OA1, OA2) from the center of the object-side surface (S1) of the first lens (111) to the image sensor (190), and is the sum of the first to third optical axis distances (T1, T2, T3), and can satisfy the condition: T1 < T2. In addition, the condition: 1 < T2 / (T1+T3) < 3 can be satisfied. Since the image sensor (190) is arranged parallel to the first direction (X), the image sensor (190) and the first reflective member (P1) may not overlap in the first direction (X).

[0244] As shown in Fig. 16, the inclination angle (R1) of the reflective surface (PR1) of the first reflective member (P1) may be less than 45 degrees with respect to an axis perpendicular to the first optical axis (OA1), for example, in a range of 40 degrees to 44 degrees. That is, the second optical axis (OA2) may be less than 90 degrees with respect to the first optical axis (OA1). Accordingly, the lenses of the second lens group (LG2) arranged along the second optical axis (OA2) are spaced apart from the object side relative to the axis (X1), and the optical filter (192) and the image sensor (190) are not parallel to the axis perpendicular to the first optical axis (OA1) and may overlap with the first reflective member (P1) in the first direction (X).

[0245] As shown in Fig. 17, the second reflective member (P2) can reflect incident light toward the object. Accordingly, the optical filter (192) and the image sensor (190) can be positioned closer to the object than the second reflective member (P2). Since the optical filter (192) and the image sensor (190) are positioned in the object-side direction of the second reflective member (P2), the height of the optical system in the third direction (Z) can be reduced.

[0246] The invention can move the first lens group (LG1) in the direction of the second optical axis (OA) for OIS driving. For example, as shown in (A)(B) of FIG. 18, the first optical axis (OA1) passing through the first and second lenses (111, 112) of the first lens group (LG1) can move toward one end (Pz1) of the incident surface (PS1) of the first reflective member (P1), or the first optical axis (OA1) can move toward the other end (Pz2) of the incident surface (PS1) of the first reflective member (P1). By (A)(B) of FIG. 7, the lenses of the first lens group (LG1) can move in the direction of the second optical axis (OA), and in this case, the first lens group (LG1) can be connected to a driving unit such as an actuator. In addition, as shown in (A)(B) of FIG. 18, a part of the effective area of ​​at least one of the first and second lenses (111, 112) may not overlap in the third direction (Z), i.e., an area outside one end (Pz1) or the other end (Pz2) of the incident surface (PS1) of the first reflective member (P1).

[0247]

[0248] (A)(B) of Fig. 19 are graphs showing the diffraction MTF (Modulation Transfer Function) in the infinity mode and near-field mode in the optical system of Fig. 12 and Fig. 13, and are graphs showing the luminance ratio (modulation) according to the spatial frequency.

[0249] Fig. 20 is a graph showing the aberration characteristics in the infinity mode of the optical system of Fig. 12, and Fig. 21 is a graph showing the aberration characteristics in the near mode of the optical system of Fig. 13. Referring to Figs. 20 and 21, the graphs are graphs measuring spherical aberration (longitudinal spherical aberration), astigmatic field curves, and distortion from left to right in the aberration graphs of the optical system. The X-axis may represent the focal length (mm) and the distortion (%), and the Y-axis may represent the height of the image. In addition, the graph for spherical aberration is a graph for light in wavelength bands of about 470 nm, about 555 nm, about 610 nm, and about 650 nm, and the graphs for astigmatism and distortion are graphs for light in wavelength bands of 555 nm.

[0250] As shown in Fig. 22, this is a graph showing relative illumination according to the relative sensor height (relative Fielded height) in the infinity and near-distance modes of the optical systems of Figs. 12 and 13. As shown in Fig. 22, it can be seen that the relative illumination is the highest in the center (0.0) field (Field) of the image sensor and is 40% or more to the end (1.0) field. The optical system (1000) according to the second embodiment has improved resolution and can have good optical performance not only in the center but also in the periphery of the field of view (FOV). The lens system of the embodiment according to the present invention can have spherical aberration, astigmatism, distortion aberration, chromatic aberration, and coma aberration all well-corrected with a configuration of 7 lenses or less.

[0251]

[0252] The optical system (1000) according to the embodiment disclosed above can satisfy at least one or two or more of the mathematical equations described below. Accordingly, the optical system (1000) according to the embodiment can have improved optical characteristics. For example, when the optical system (1000) satisfies the mathematical equations, the optical system (1000) can effectively control aberration characteristics such as chromatic aberration and distortion aberration, and can have good optical performance even in the center and periphery of the field of view (FOV). The optical system (1000) can have improved resolution and can have a slimmer and more compact structure.

[0253] [Mathematical Formula 1] 1 < nLG1

[0254] In mathematical expression 1, nLG1 is the number of lenses of the first lens group (LG1), and is 2. Preferably, 1 < nLG1 < 3 can be satisfied. In addition, 2 ≤ nLG2 / nLG1 < 3 can be satisfied.

[0255] [Equation 2] 0.5 < CA11 / PSA11 < 1.7

[0256] CA11 is the effective length of the first surface (S1) of the first lens (101, 111), and PSA11 is the length of the incident surface (PS1) of the first reflective member (P1) in the first direction (X). By satisfying mathematical expression 2, light incident through the first lens (101, 111) can be refracted to the entire area of ​​the incident surface (PS1) of the first reflective member (P1). Mathematical expression 2 can satisfy 1 < CA11 / PSA11 < 1.5.

[0257] [Mathematical Formula 3] 1 < TD1 / MG1 < 5

[0258] In mathematical expression 3, TD1 is the optical axis distance of the first lens group (LG1), and MG1 is the optical axis spacing between the first lens group (LG1) and the first reflective member (P1). Mathematical expression 3 can satisfy 1 < TD1 / MG1 < 3.

[0259] [Mathematical Formula 4] 0 < (CT5+CT6) / (CT1+CT2) < 1

[0260] In mathematical expression 4, the sum of the central thicknesses (CT5, CT6) of the fifth and sixth lenses can be set thinner than the sum of the central thicknesses (CT1, CT2) of the first and second lenses. Accordingly, the movement of the second lens group including the fifth and sixth lenses can be facilitated. Since mathematical expression 4 is satisfied, the aberration characteristics of the optical system can be improved and power consumption can be reduced.

[0261] [Equation 4-1] 1.5 < (CT1+CT2) / (CTn+CTn-1) < 5

[0262] In mathematical expression 4-1, the sum of the central thickness (CTn) of the nth lens and the central thickness (CTn-1) of the n-1th lens can be set to be thinner than the sum of the central thicknesses of the first and second lenses.

[0263] [Mathematical Formula 5] 0 < L1R1*L1R2

[0264] L1R1 is the radius of curvature of the object-side surface of the first lens, and L1R2 is the radius of curvature of the sensor-side surface of the first lens. By satisfying mathematical expression 5, the first lens can have a convex meniscus shape toward the object, and can increase the amount of light incident through the first lens.

[0265] [Equation 6] 0 < FLG1

[0266] FLG1 is the focal length of the first lens group and can have positive power. Since it satisfies mathematical expression 6, it can focus the incident light toward the first optical axis (OA1) and increase the amount of light incident on the incident surface (PS1) of the first reflective member (P1).

[0267] [Mathematical Formula 7] 0 < TD1 / TD2 < 1

[0268] TD1 is the first optical axis distance of the first lens group, and TD2 is the second optical axis distance of the second lens group (LG2). Accordingly, the imaging characteristics of the optical system can be improved by the lenses, and AF operation can be enabled. Preferably, 0.2 < TD1 / TD2 < 0.8 can be satisfied.

[0269] [Equation 8] 0.5 < |FLG1 / FLG2| < 3

[0270] In mathematical expression 8, the absolute value of the focal length (FLG1) of the first lens group and the absolute value of the focal length (FLG2) of the second lens group can be set. The focal length of the movable lens group can be smaller than the focal length of the fixed lens group. The aberration characteristics of the optical system can be improved by the focal lengths of these lens groups. Preferably, the first embodiment satisfies 0.5 < |FLG1 / FLG2| < 1, and the second embodiment satisfies 1 < |FLG1 / FLG2| < 2.

[0271] [Equation 9] 5 < TTL / TD1 < 25

[0272] In mathematical expression 9, TTL is the optical axis distance in the first and second axis directions from the center of the object-side surface of the first lens through the first and second reflective members to the upper surface of the image sensor (190). Since mathematical expression 9 is satisfied, the optical system does not need to be arranged lengthwise in any one axis direction. Preferably, 5 < TTL / TD1 < 15 can be satisfied.

[0273] [Equation 10] 2 < CT_Max / CT_Min < 6

[0274] CT_Max is the maximum central thickness among the lenses, and CT_Min is the minimum central thickness among the lenses. When mathematical expression 10 is satisfied, the optical system (1000) can be reduced in size, for example, the total track length (TTL) can be reduced. Preferably, 2 < CT_Max / CT_Min < 4 can be satisfied.

[0275]

[0276] [Mathematical Formula 11] 1 < CA11 / CA32 < 3

[0277] In mathematical expression 11, since the effective length (CA11) of the object-side surface of the first lens is arranged to be greater than the effective length (CA32) of the sensor-side surface of the third lens, the amount of light incident on or emitted from the first reflective member (P1) by the first lens (101, 111) can be increased. In addition, since mathematical expression 11 is satisfied, the decrease in the amount of light that proceeds through the first lens arranged on the incident side of the first reflective member (P1) and the third lens arranged on the emission side of the first reflective member (P1) can be suppressed. Preferably, 1 < CA11 / CA32 < 2.5 can be satisfied.

[0278] [Equation 12] 0 < CA31 / CAn2 < 2

[0279] CAn2 is the effective length of the sensor-side surface of the last lens. In mathematical expression 12, the effective lengths of the lenses adjacent to the first and second reflective members (P1, P2) can be set, thereby reducing the influence of the aberration characteristics of the lenses. That is, by setting the effective length (CA31) of the object-side surface of the third lens (103, 113, 123) adjacent to the first reflective member (P1) and the effective length (CAn2) of the sensor-side surface of the last lens (107, 116) adjacent to the second reflective member (P2), the aberration characteristics of the optical system can be improved. An embodiment can satisfy 1 < CA31 / CAn2 < 2.

[0280] [Equation 13] 1 < CA11 / CAn2 < 3

[0281] Since mathematical expression 13 is satisfied, the deterioration of the chromatic aberration characteristics of the foldable optical system can be prevented. Preferably, 1.2 < CA11 / CAn2 < 2 can be satisfied.

[0282] [Mathematical Formula 14] 1 < CA_Max / CA_Min < 3

[0283] CA_Max is the maximum effective length among the lens surfaces of the lenses, and CA_Min is the minimum effective length among the lens surfaces of the lenses. Since it satisfies mathematical expression 13, the aberration characteristics of the optical system can be improved. Preferably, 1.4 < CA_Max / CA_Min < 2.5 can be satisfied.

[0284] [Equation 15] 3 < CA1 / CT1 < 9

[0285] Since the effective length (CA1) and the central thickness (CT1) of the first lens are satisfied in mathematical expression 15, the incident light can be controlled and the thickness of the first lens group can be provided slimly. Preferably, 3 < CA1 / CT1 < 7 can be satisfied.

[0286] [Equation 16] 2 < CA2 / CT2 < 15

[0287] Since the effective length (CA2) and the central thickness (CT2) of the second lens are satisfied in mathematical expression 16, the incident light can be controlled and the thickness of the first lens group can be provided slimly. Preferably, 5 < CA2 / CT2 < 13 can be satisfied.

[0288] [Equation 17] 2 < CA3 / CT3 < 10

[0289] Since the effective length (CA3) and the central thickness (CT3) of the third lens in mathematical expression 17 are satisfied, light passing through the third lens adjacent to the first reflective member (P1) can be controlled and the height of the optical system can be slimmed down. Preferably, 2 < CA3 / CT3 < 5 can be satisfied.

[0290] [Mathematical Formula 18] 1 < CAn / CTn < 12

[0291] Since the effective length (CAn) and central thickness (CTn) of the last lens in mathematical expression 18 are satisfied, the path of the light emitted through the last lens can be controlled and a slim optical system can be provided. Preferably, 5 < CA3 / CT3 < 10 can be satisfied.

[0292] [Equation 19] 1.5 < D3 / TD2 < 2.5

[0293] In mathematical expression 19, D3 is the distance between the first and second reflective elements (P1, P2), and can be provided to be greater than the optical axis distance (TD2) of the second lens group arranged between the first and second reflective elements (P1, P2). Preferably, 1.7 < D3 / TD2 < 2.2 can be satisfied.

[0294]

[0295] [Mathematical Formula 20] 50 < Vd1* Nd1 <100

[0296] In mathematical expression 20, the Abbe number and refractive index of the first lens can be set. Preferably, 60 < Vd1* Nd1 < 85 can be satisfied.

[0297] [Equation 21] 1.6 < Nd2

[0298] In mathematical expression 21, the refractive index of the second lens can be set to exceed 1.6, thereby controlling light dispersion within the first lens group.

[0299] [Mathematical Formula 21-1] (CA1-CA2) < (CA3-CA2)

[0300] In mathematical expression 21-1, the difference in the effective lengths of the second and third lenses is provided to be greater than the difference in the effective lengths of the first and second lenses, thereby reducing the effective length of the second lens group. Accordingly, an increase in the height of the optical system can be suppressed.

[0301]

[0302] [Mathematical Formula 22] 0 < L1R1 / L2R2 < 3

[0303] In mathematical expression 22, the radius of curvature of the object-side surface of the first lens (L1R1) and the radius of curvature of the sensor-side surface of the second lens (L2R2) can be set.

[0304] [Equation 23] 0 < |L1R1 / L3R1| < 4

[0305] In mathematical expression 23, L3R1 is the radius of curvature of the object-side surface of the third lens. In mathematical expression 23, the radius of curvature of the object-side surface of the object-side lenses of the first and second lens groups can be set, thereby improving the aberration characteristics of the propagating light. Preferably, the embodiment can satisfy the condition: 1 < |L1R1 / L3R1| < 1.5.

[0306] [Equation 24] 0 < |L2R2 / L3R1| < 3

[0307] In mathematical expression 24, L2R2 and L3R1 set the radius of curvature of the lens adjacent to the first reflective element (P1), thereby improving the aberration characteristics of light traveling through the second lens group. Preferably, 0.5 < |L2R2 / L3R1| < 2.5 can be satisfied.

[0308] [Equation 25] 35 < Ave_Ad < 45

[0309] In mathematical expression 25, the average Abbe number of lenses in the optical system can be set.

[0310] [Equation 25-1] 1.5 < Ave_Nd < 1.8

[0311] In mathematical expression 25, the average refractive index of the lenses in the optical system can be set.

[0312]

[0313] [Equation 26] 1 < TTL / T2 < 3

[0314] T2 is the second optical axis distance from the center of the reflective surface of the first reflective member (P1) to the center of the reflective surface of the second reflective member (P2) along the second optical axis (OA2). Since it satisfies mathematical expression 26, the length of the first direction (X) of the optical system can be reduced. Preferably, 1.2 < TTL / T2 < 2 can be satisfied.

[0315] [Mathematical Formula 27] 1 < TTL / F1 < 3

[0316] In mathematical expression 27, the total length of the optical system in the first and second directions and the focal length (F1) of the first lens (101, 111) can be set. Since mathematical expression 27 is satisfied, the refractive power of the first lens can be controlled and the TTL can be reduced. Preferably, the embodiment can satisfy 1 < TTL / F1 < 2.

[0317] [Equation 28] 1 < |F / F3| < 5

[0318] In mathematical expression 28, the overall focal length (F) of the optical system and the focal length of the third lens (103, 113) adjacent to the first reflective member (P1) can be set. Since mathematical expression 28 is satisfied, the optical system can improve the resolution by controlling the refractive power of the incident light, and can improve the aberration characteristics such as chromatic aberration and distortion aberration of the optical system. Preferably, 2 < |F / F3| < 4 can be satisfied.

[0319] [Equation 29] 1 < |Fn / F3| < 10

[0320] In mathematical expression 29, the focal length (F1) of the third lens (103, 113) and the focal length (Fn) of the last lens (107, 116) of the optical system can be set. Since mathematical expression 29 is satisfied, the refractive power of the third lens and the last lens of the optical system can be controlled to improve the resolution. Preferably, 3 < |Fn / F3| < 8 can be satisfied.

[0321] [Equation 30] 1 < TTL / F < 2

[0322] In mathematical expression 30, the total length of the optical system in the first and second directions and the total focal length can be set. Since mathematical expression 30 is satisfied, the length of the optical system can be adjusted. Preferably, 1 < TTL / F < 1.6 can be satisfied.

[0323]

[0324] [Mathematical Formula 31] 1 < F1 / L1R1 < 10

[0325] In mathematical expression 31, the focal length of the first lens (101, 111) and the radius of curvature (L1R1) of the object-side surface (S1) of the first lens can be set. Accordingly, the optical system can improve the aberration characteristics of the first lens (101, 111) and adjust the optical axis distance of the first lens group. Preferably, 2 < F1 / L1R1 < 6 can be satisfied.

[0326] [Equation 32] 1 < |F2 / L2R2| < 7

[0327] In mathematical expression 32, the focal length of the second lens (102, 112) and the radius of curvature (L2R2) of the sensor-side surface (S4) of the second lens can be set. Accordingly, the optical system can improve the aberration characteristics of the second lens (102, 112) and adjust the optical axis distance of the first lens group. An embodiment can satisfy 2 < |F2 / L2R2| < 6.

[0328] [Equation 33] 0 < L6R1

[0329] In mathematical expression 33, the radius of curvature (L6R1) of the object-side surface of the sixth lens (106, 116) can be set to a positive value. Since mathematical expression 33 is satisfied, light traveling through the second lens group can be refracted by the second reflective member.

[0330] [Mathematical Formula 34] 41 degrees < R1 ≤ 45 degrees

[0331] R1 represents the inclination angle of the reflective surface (PR1) of the first reflective member (P1). The optical system can position the components including the image sensor (190) and the optical filter (192) closer to the object by setting the inclination angle of the reflective surface (PR1) of the first reflective member (P1) to less than 45 degrees. Accordingly, the height of the optical system in the direction of the first optical axis (OA1) (i.e., Z) can be reduced. As another example, the reflective surface of the second reflective member (P2) can be inclinated at the angle (R1).

[0332]

[0333] [Mathematical Formula 35] 10 degrees < FOV < 50 degrees

[0334] FOV (Field of view) refers to the angle of view (Degree) of the optical system (1000), and can provide an optical system of less than 50 degrees. The FOV can be 15 degrees or more, for example, in the range of 15 degrees to 45 degrees.

[0335] [Equation 36] 2 < F / EPD < 10

[0336] In mathematical expression 36, the entrance pupil (EPD) and the overall focal length (F) of the optical system (1000) can be set. When mathematical expression 36 is satisfied, the optical system (1000) can control the overall brightness and have good optical performance in the center and periphery of the field of view (FOV). Preferably, mathematical expression 36 can satisfy 3 < F / EPD < 7.

[0337] [Equation 37] 5 < TTL / ImgH < 15

[0338] In mathematical expression 37, the total optical axis length (TTL) of the optical system and the diagonal length (ImgH) from the optical axis of the image sensor (190) can be set. If mathematical expression 60 is satisfied, high-quality implementation and a slim structure can be achieved. Preferably, in mathematical expression 37, the first embodiment satisfies 7 < TTL / ImgH < 14, and the second embodiment satisfies 5 < TTL / ImgH < 10.

[0339] [Equation 38] 1 < BFLmax / ImgH < 6

[0340] Mathematical expression 38 can set the maximum optical axis distance (BFLmax) between the image sensor (190) and the last lens and the length in the diagonal direction from the optical axis of the image sensor (190). When Mathematical expression 38 is satisfied, the optical system (1000) can secure the maximum BFL (Back focal length), can arrange a second reflective member between the last lens and the image sensor (190), and can have good optical characteristics in the center and periphery of the field of view (FOV). Preferably, in Mathematical expression 38, the first embodiment can satisfy 25 < BFLmax / ImgH < 6, and the second embodiment can satisfy 2 < BFLmax / ImgH < 4.

[0341] [Mathematical Formula 39] 2mm < ImgH

[0342] ImgH is half of the diagonal length of the image sensor (190). In mathematical expression 39, by setting the diagonal length of the image sensor (190) to exceed 4 mm, an optical system having high resolution can be provided. Mathematical expression 39 can preferably satisfy 2 mm < ImgH < 6 mm or 2 mm < ImgH < 5 mm.

[0343] [Mathematical Formula 40] 5mm < F < 40mm

[0344] In mathematical expression 40, the overall focal length (F) can be set to suit the optical system, and preferably, 10 mm < F < 30 mm can be satisfied.

[0345] [Mathematical Formula 41] 10mm < TTL < 40mm

[0346] In mathematical expression 41, TTL (Total track length) means the distance from the center of the first surface (S1) of the first lens to the upper surface of the image sensor (190) on the optical axis (OA). Preferably, mathematical expression 41 can satisfy 15 mm < TTL < 35 mm.

[0347] [Mathematical Formula 42] 4mm < BFLmin < 12mm

[0348] Mathematical expression 42 can set the minimum BFL value of the foldable optical system. That is, the BFL can secure the installation space of the second reflective member and the optical filter (192), improve the arrangement of components such as the second reflective member and the optical filter between the image sensor (190) and the final lens, improve the assembling thereof, and improve the joint reliability. Mathematical expression 42 can preferably satisfy 5 mm < BFLmin < 11 mm.

[0349]

[0350] [Equation 43] 0 < |Max_Distortion| < 3

[0351] In mathematical expression 43, distortion refers to the maximum value or the maximum value of distortion from the center (0.0F) of the image sensor to the diagonal end (1.0F) based on the optical characteristics detected by the image sensor (190). When the optical system (1000) satisfies mathematical expression 43, the optical system (1000) can improve the distortion characteristics and set conditions for image processing. Preferably, 0 < |Max_Distortion| < 1.5 can be satisfied.

[0352] Table 1 shows the distortion characteristics from the center (Dist F1) to the end (Dist F11) of the first to third embodiments.

[0353] Sensor height Example 1 Example 2 Dist(F1) 0 0 Dist(F2) 0.01285 0.0117 Dist(F3) 0.051 0.04689 Dist(F4) 0.11348 0.10581 Dist(F5) 0.19948 0.18889 Dist(F6) 0.30927 0.29709 Dist(F7) 0.44516 0.43258 Dist(F8) 0.6124 0.59954 Dist(F9) 0.8191 0.80449 Dist(F10) 1.07432 1.05548 Dist(F11) 1.38367 1.3601

[0354]

[0355] [Mathematical Formula 44] 0 < Md1(D1 / D2) < 2

[0356] In mathematical expression 43, the distance (D1) between the first reflective member and the second lens group and the distance (D2) between the second reflective member and the second lens group can be set in the first mode. An embodiment can satisfy 0 < Md1(D1 / D2) < 1.

[0357] [Mathematical Formula 45] 0 < Md2(D1 / D2) < 1

[0358] In mathematical expression 45, the distance (D1) between the first reflective member and the second lens group and the distance (D2) between the second reflective member and the second lens group can be set in the second mode. Preferably, the embodiment can satisfy 0 < Md2(D1 / D2) < 0.5.

[0359] [Equation 46] 1 < T1 / T3 < 3

[0360] In mathematical expression 45, a first optical axis distance (T1) from the center of the object-side surface (S1) of the first lens (101) to the center of the reflective surface (PR1) of the first reflective member (P1) and an optical axis distance (T3) from the center of the reflective surface (PR2) of the second reflective member (P2) to the center of the upper surface of the image sensor (190) can be set. Preferably, 2 < T1 / T3 < 3 can be satisfied.

[0361]

[0362] [Equation 47]

[0363]

[0364] In mathematical expression 47, Z may represent Sag, which is the distance from any position on the aspherical surface to the vertex of the aspherical surface in the direction of the optical axis. Y may represent the distance from any position on the aspherical surface to the optical axis in the direction perpendicular to the optical axis. c may represent the curvature of the lens, and K may represent the conic constant. In addition, A, B, C, D, E, F, etc. may represent aspheric coefficients.

[0365]

[0366] An optical system (1000) according to an embodiment can satisfy at least one or more mathematical expressions from mathematical expressions 1 to 46, have improved resolution, and improve aberration and distortion characteristics. The optical system (1000) can secure a BFL for a foldable optical system, and have good optical performance in the center and periphery of the field of view (FOV). In addition, when the optical system (1000) satisfies at least one mathematical expression from mathematical expressions 1 to 46, a slimmer and more compact optical system and a camera module having the same can be provided.

[0367]

[0368] Table 2 shows the items of the mathematical formulas described above in the optical system (1000) according to the embodiments, and shows the TTL, BFL, F value which is the total effective focal length, ImgH, focal length of each lens, edge thickness (mm), and refractive power (FLG1, FLG2) of each lens group of the optical system (1000).

[0369] Item Example 1 Example 2 F19.5 19.5 F115.345 17.485 F2-19.699-24.833 F36.83 16.578 F4-7.219-5.328 F5-50.528 14.281 F625.285-30.454 F7-46.739 FLG143.01 242.935 FLG250.544 30.965 ET10.68 40.64 0ET20.9330.880ET30.5930.609ET40.9270.995ET50.4820.588ET60.4410.685ET70.640FOV19 .45120.116EPD3.6193.675F#0.0000.000ImgH2.1043.505BFLmin8.7659.187TTL27.00027.000

[0370]

[0371] Tables 3 and 4 show the results for the mathematical expressions 1 to 46 described above in the optical system (1000) according to the embodiment. Referring to Tables 3 and 4, it can be seen that the optical system (1000) satisfies at least one, two or more, or three or more of the mathematical expressions 1 to 46. Accordingly, the optical system (1000) can improve optical performance and optical characteristics in the center and periphery of the field of view (FOV).

[0372] Mathematical Formula Example 1 Example 2 11 < nLG1 2220.5 < CA11 / PSA11 < 1.71.0291.11431 < TD1 / MG1 < 51.2001.24640 < (CT5+CT6) / (CT1+CT2) < 10.4760.60950 < L1R1*L1R2 111.01952.53460 < FLG1 43.01242.93570 < TD1 / TD2 < 10.4550.47180.5 < |FLG1 / FLG2| < 30.8511.38795 < TTL / TD1 < 2511.25011.457102 < CT_Max / CT_Min < 63.0002.913111< CA11 / CA32 <31.6111.620120 < CA31 / CAn2 < 21.0131.061131 < CA11 / CAn2 < 31.5451.618141 < CA_Max / CA_Min < 31.7111.734153 < CA1 / CT1 < 94.5634.689162 < CA2 / CT2 < 1510.09710.306172 < CA3 / CT3 < 103.3603.227181 < CAn / CTn < 128.7408.393191.5 < D3 / TD2 < 2.51.9322.0662050 < Vd1* Nd1 <10074.78678.819211.6 < Nd21.6131.609220 < L1R1 / L2R2 < 31.3330.667230 < |L1R1 / L3R1| < 41.2251.060

[0373] Mathematical Formula Example 1 Example 2 241 < nLG1 2 1.590 250.5 < CA11 / PSA11 < 1.7 1.029 4 0.78 2261 < TD1 / MG1 < 51.200 1.673 270 < (CT5 + CT6) / (CT1 + CT2) < 10.476 1.544 280 < L1R1 * L1R2 1 11.019 2.964 290 < FLG1 4 3.012 4.629 300 < TD1 / TD2 < 10.455 1.385 3 10.5 < |FLG1 / FLG2| < 30.8513.392325 < TTL / TD1 < 2511.2503.213332 < CT_Max / CT_Min < 63.0005.227341< CA11 / CA32 <31.611Satisfied350 < CA31 / CAn2 < 21.01320.116361 < CA11 / CAn2 < 31.5455.306371 < CA_Max / CA_Min < 31.7117.702383 < CA1 / CT1 < 94.5632.895392 < CA2 / CT2 < 1510.0973.51402 < CA3 / CT3 < 103.36019.500411 < CAn / CTn < 128.74027.000421.5 < D3 / TD2 < 2.51.9329.1874350 < Vd1* Nd1 <10074.7861.360441.6 < Nd21.6130.492450 < L1R1 / L2R2 < 31.3330.176460 < |L1R1 / L3R1| < 41.2252.382

[0374]

[0375] Fig. 23 is a drawing illustrating an example of a mobile terminal to which a camera module according to an embodiment is applied. Referring to Fig. 23, the mobile terminal (1) may include a camera module (10) provided on the rear. The camera module (10) may include an image capturing function. In addition, the camera module (10) may include at least one of an auto focus function, a zoom function, and an OIS function.

[0376] The above camera module (10) can process still images or video frames obtained by the image sensor (190) in shooting mode or video call mode. The processed image frames can be displayed on the display unit (not shown) of the mobile terminal (1) and stored in a memory (not shown). In addition, although not shown in the drawing, the camera module may be further arranged on the front of the mobile terminal (1).

[0377] For example, the camera module (10) may include a first camera module (10A) and a second camera module (10B). At this time, at least one of the first camera module (10A) and the second camera module (10B) may include the optical system (1000) described above. Accordingly, the camera module (10) may have a slim structure and may have improved distortion and aberration characteristics. In addition, the camera module (10) may have good optical performance at the center and periphery of the field of view (FOV).

[0378] In addition, the mobile terminal (1) may further include an auto-focus device (31). The auto-focus device (31) may include an auto-focus function using a laser. The auto-focus device (31) may be mainly used in conditions where the auto-focus function using the image of the camera module (10) disclosed above is degraded, for example, in a close range of 10 m or less or in a dark environment. The auto-focus device (31) may include a light-emitting unit including a vertical cavity surface-emitting laser (VCSEL) semiconductor element, and a light-receiving unit that converts light energy into electrical energy, such as a photodiode.

[0379] In addition, the mobile terminal (1) may further include a flash module (33). The flash module (33) may include a light-emitting element that emits light internally. The flash module (33) may be operated by the camera operation of the mobile terminal or by the user's control.

[0380]

[0381] Fig. 24 is an example of a plan view of a vehicle to which a camera module or optical system according to an embodiment of the invention is applied. Referring to Fig. 30, a vehicle camera system according to an embodiment of the invention includes an image generating unit (11), a first information generating unit (12), a second information generating unit (21, 22, 23, 24, 25, 26), and a control unit (14). The image generating unit (11) may include at least one camera module (13) disposed in the vehicle, and may capture images of the front of the vehicle and / or the driver to generate a front image or an interior image of the vehicle. The image generating unit (11) may capture images of the surroundings of the vehicle in one or more directions as well as the front of the vehicle using the camera module (13), to generate an image of the surroundings of the vehicle. Here, the front image and the surrounding images may be digital images, and may include color images, black and white images, infrared images, etc. In addition, the front image and the surrounding images may include still images and moving images. The image generation unit (11) provides the driver image, the front image, and the surrounding image to the control unit (14). Next, the first information generation unit (12) may include at least one radar and / or camera placed in the vehicle, and detects the front of the vehicle to generate first detection information. Specifically, the first information generation unit (12) is placed in the vehicle, and detects the position and speed of vehicles located in front of the vehicle, the presence and position of pedestrians, etc. to generate the first detection information.

[0382] By using the first detection information generated by the first information generating unit (12), the distance between the own vehicle and the vehicle in front can be controlled to be maintained at a constant level, and the stability of vehicle operation can be improved in specific preset cases, such as when the driver wants to change the driving lane of the own vehicle or when backing up and parking. The first information generating unit (12) provides the first detection information to the control unit (14). The second information generating unit (21, 22, 23, 24, 25, 26) detects each side of the own vehicle based on the front image generated by the image generating unit (11) and the first detection information generated by the first information generating unit (12), and generates second detection information. Specifically, the second information generating unit (21, 22, 23, 24, 25, 26) may include at least one radar and / or camera disposed in the own vehicle, and may detect the position and speed of vehicles located on the side of the own vehicle or capture images. Here, the second information generating units (21, 22, 23, 24, 25, 26) can be placed at the front two corners, side mirrors, and rear center and rear two corners of the vehicle, respectively.

[0383] At least one information generating unit of these vehicle camera systems may include the optical system and the camera module having the same as described in the above-described embodiments, and may provide or process information acquired through the front, rear, each side, or corner area of ​​the vehicle to a user to enable autonomous driving or to protect the vehicle and objects from surrounding safety. The optical system of the camera module according to the embodiment of the invention may be installed in multiple units in a vehicle to enhance safety regulations, autonomous driving functions, and convenience. In addition, the optical system of the camera module is applied in a vehicle as a component for control such as a lane keeping assistance system (LKAS), a lane departure warning system (LDWS), and a driver monitoring system (DMS). These vehicle camera modules can implement stable optical performance even with changes in ambient temperature and provide modules with competitive prices, thereby ensuring the reliability of vehicle components.

[0384]

[0385] The features, structures, effects, etc. described in the embodiments above are included in at least one embodiment of the present invention, and are not necessarily limited to just one embodiment. Furthermore, the features, structures, effects, etc. exemplified in each embodiment can be combined or modified in other embodiments by those skilled in the art to which the embodiments pertain. Therefore, the contents related to such combinations and modifications should be construed as falling within the scope of the present invention.

[0386] 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. First reflective member; A second reflective member spaced apart from the first reflective member; A first lens group having first and second lenses arranged along a first optical axis and disposed between the first reflective member and the object; and A second lens group having a plurality of lenses arranged between the first and second reflective members and sequentially aligned along a second optical axis different from the first optical axis, The first lens closest to the object has positive power, The object-side surfaces of the first and second lenses have a convex shape on the first optical axis, The number of lenses in the second lens group is at least twice the number of lenses in the first lens group, The lens facing the emission surface of the first reflective member has a convex object-side surface, Among the lenses of the second lens group, the lens closest to the second reflective member is the nth lens, The above n is 6 or more, An optical system wherein the second lens has negative power.

2. In paragraph 1, An optical system wherein the power of the first lens group has a positive value.

3. In paragraph 2, An optical system in which the power of the second lens group has a positive value.

4. In paragraph 1, An optical system in which the n-1th lens among the lenses of the first and second lens groups has the minimum effective length among the effective lengths of the lenses.

5. In any one of paragraphs 1 to 4, The second lens group has third to seventh lenses, The above seventh lens is the nth lens, An optical system wherein the second lens group is moved along the second optical axis.

6. In paragraph 5, The above first reflective member faces the second lens and the third lens, An optical system in which the power of the third lens has positive power.

7. In paragraph 5, An optical system wherein the effective length of the second lens is greater than the effective length of each of the third to seventh lenses.

8. In paragraph 1, The second lens group has third to sixth lenses, The above sixth lens is the nth lens, An optical system wherein the second lens group is moved along the second optical axis.

9. In paragraph 8, An optical system wherein the third lens has positive power and has a biconvex shape on the second optical axis.

10. In paragraph 8, An optical system in which the sensor-side surface of the sixth lens has a concave shape.

11. In any one of paragraphs 1 to 4, An optical system in which the nth lens has negative power.

12. In any one of paragraphs 1 to 4, An optical system wherein the average of the effective lengths of the first lens is greater than the average of the effective lengths of the lenses of the second lens group.

13. In any one of paragraphs 1 to 4, The reflective surface of the first reflective member has an inclination angle R1 with respect to an axis perpendicular to the first optical axis, Mathematical formula: 41 < R1 ≤ 45 An optical system that satisfies .

14. In any one of paragraphs 1 to 4, An image sensor that converts light reflected from the second reflective member into an electrical signal; and an optical filter disposed between the image sensor and the second reflective member, At least one of the optical filter and the image sensor overlaps the first reflective member in a direction parallel to the second optical axis, An optical system wherein the diagonal length of the image sensor is greater than the effective length of at least one of the lenses of the second lens group.

15. In any one of paragraphs 1 to 4, An image sensor that converts light reflected from the second reflective member into an electrical signal; and an optical filter disposed between the image sensor and the second reflective member, The above second reflective member reflects the incident light toward the object, The optical filter and the image sensor are positioned closer to the second reflective member and the object, An optical system wherein the diagonal length of the image sensor is greater than the effective length of the first lens.

16. In any one of paragraphs 1 to 4, An optical system in which the first lens group moves in the second optical axis direction on the first reflective member.

17. In any one of paragraphs 1 to 4, The first and second reflective members are prisms, An optical system wherein the lenses of the first and second lens groups are aspherical lenses.

Images