Optical system and camera module

Abstract

An optical system disclosed in an embodiment of the invention comprises: a first reflective member; a second reflective member spaced from the first reflective member; first and second lenses disposed between the first reflective member and an object and sequentially arranged along a first optical axis; and third to sixth lenses sequentially arranged between the first and second reflective members along a second optical axis orthogonal to the first optical axis, wherein the first lens has positive refractive power and has a meniscus shape convex toward the object, the third lens has positive refractive power and has a convex object-side surface, the sixth lens has negative refractive power and has a concave object-side surface, and the focal length of a first lens group having the first and second lenses may have a positive value.

Description

Optical system and camera module

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

[0002] Camera modules perform the function of capturing objects and saving them as images or videos, and are installed in various applications. In particular, camera modules are manufactured to be ultra-compact, allowing them to be applied not only to portable devices such as smartphones, tablet PCs, and laptops, but also to drones and vehicles, providing a variety of functions. For example, the optical system of a camera module may include an imaging lens that forms an image and an image sensor that converts the formed image into an electrical signal. In this case, the camera module can perform an autofocus (AF) function that aligns the focal length of the lens by automatically adjusting the distance between the image sensor and the imaging lens, and can perform a zooming function of zooming up or zooming out to increase or decrease the magnification of distant objects through a zoom lens. Additionally, the camera module employs image stabilization (IS) technology to correct or prevent image shaking caused by camera movement resulting from unstable mounting devices or user movements.

[0003] The most important element for such camera modules to obtain an image is the imaging lens that forms the image. Recently, interest in high resolution has been increasing, and research is being conducted on optical systems containing multiple lenses to achieve this. For example, research is being conducted using multiple imaging lenses with positive (+) or negative (-) refractive power to achieve high resolution.

[0004] However, when multiple lenses are included, there is a problem in that it is difficult to derive excellent optical and aberration characteristics. In addition, when multiple lenses are included, the overall length and height may increase due to the thickness, spacing, and size of the multiple lenses, which leads to a problem in that the overall size of the module including the multiple lenses increases.

[0005] Furthermore, the size of image sensors is increasing to achieve high resolution and high image quality. However, as the size of the image sensor increases, the Total Track Length (TTL) of the optical system containing multiple lenses also increases; consequently, there is a problem in that the thickness of devices such as cameras and mobile terminals containing the said optical system also increases. Therefore, a new optical system capable of solving the aforementioned problem is required.

[0006] An embodiment of the invention may provide a first lens group having a plurality of lenses between an object and a first reflective member, an optical system having a plurality of lenses between the first reflective member and the second reflective member, and a camera module. Accordingly, an image sensor may be positioned in a direction parallel to the axial direction passing through the center of the plurality of reflective members. That is, the invention aims to provide an optical system and a camera module arranged such that the optical axis of the last lens and the center axis of the image sensor are orthogonal. An embodiment provides a foldable optical system and a camera module having the same.

[0007] An optical system according to an embodiment comprises: a first reflective member; a second reflective member spaced apart from the first reflective member; first and second lenses disposed between the first reflective member and an object and sequentially aligned along a first optical axis; and third to sixth lenses sequentially aligned between the first and second reflective members along a second optical axis orthogonal to the first optical axis, wherein the first lens has a positive refractive power and has a meniscus shape convex toward the object, the third lens has a positive refractive power and has a convex object-side surface, the sixth lens has a negative refractive power and has a concave object-side surface, and the focal length of the first lens group having the first and second lenses may have a positive value.

[0008] According to an embodiment of the invention, a lens group having the fourth to sixth lenses among the third to sixth lenses, or all of them, may be moved in the direction of the second optical axis. The second lens group having the third to sixth lenses may have a focal length smaller than the focal length of the first lens group and may be moved in the direction of the second optical axis.

[0009] According to an embodiment of the invention, the third lens has a positive refractive power and is fixed in position, and the lens group having the fourth to sixth lenses has a negative focal length and can be moved in the direction of the second optical axis. The second lens has a negative refractive power and can have a biconvex shape. The third lens can have a biconvex shape. The sixth lens can have a biconcave shape. The second lens has a negative refractive power and has a meniscus shape convex toward an object, and the sixth lens can have a meniscus shape convex toward a sensor.

[0010] 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 equation: 41 < R1 < 45.

[0011] According to an embodiment of the invention, the system includes 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 may overlap with the first reflective member in a direction parallel to the second optical axis.

[0012] According to an embodiment of the invention, the invention comprises 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, and the optical filter and the image sensor may be disposed closer to the second reflective member and the object.

[0013] According to an embodiment of the invention, the optical axis distance from the object side surface of the first lens along the first optical axis and the second optical axis to the top surface of the image sensor is TTL, the focal length of the first lens is F1, and the equation: 1 < TTL / F1 < 3 can be satisfied. The optical axis distance from the object side surface of the first lens along the first optical axis and the second optical axis to the top surface of the image sensor is TTL, the optical axis distance of the first lens group is TD1, and the equation: 5 < TTL / TD1 < 20 can be satisfied.

[0014] According to an embodiment of the invention, the optical axis distance of the first lens group is TD1, and the center distance between the first lens group and the first reflective member is PG1, satisfying the equation: 1 < TD1 / PG1 < 3. The first reflective member is a prism, and the second reflective member may be a mirror or a prism. The first lens may be made of glass material.

[0015] An embodiment of the invention aims to provide an optical system with improved optical characteristics having a plurality of reflective members and a plurality of lenses. An autofocus (AF) function for a subject can be provided by moving a lens located on the object side or a lens (group) located on the sensor side of a first reflective member adjacent to an object. Additionally, OIS can be adjusted using the first reflective member and / or the second reflective member.

[0016] In the embodiment, multiple lenses can correct aberration characteristics or mutually correct aberration characteristics that change due to movement. Accordingly, the optical system according to the embodiment can minimize or prevent changes in chromatic aberration and aberration characteristics that occur when the magnification changes.

[0017] The embodiment provides a tele-optical system and can minimize power consumption required depending on the operating mode. In the optical system, at least one lens included in the fixed group and the moving group may have a non-circular shape. The embodiment can reduce the height of the optical system while maintaining optical performance. Additionally, it can provide an optical system with a large effective area of ​​the lens surface adjacent to an object and suppress an increase in the thickness of a portable device having a camera module. The optical system according to the embodiment can have improved aberration characteristics and resolution by setting the surface shape, refractive power, thickness of a plurality of lenses, the spacing between adjacent lenses, and the focal length of each lens (group). The optical system and camera module according to the embodiment can have improved distortion and aberration control characteristics and can have good optical performance even at the center and periphery of the field of view (FOV).

[0018] FIG. 1 is a configuration diagram of an optical system and a camera module according to a first embodiment of the invention.

[0019] Figure 2 is a configuration diagram of the optical system in the near-field mode of Figure 1.

[0020] Figure 3 is a table showing lens data of the optical system of Figure 1.

[0021] Figure 4 is an example of the aspherical coefficients of the lenses of the optical system of Figure 1.

[0022] Figure 5 is an example in which the light path is changed by the second reflective member of Figure 1.

[0023] Figure 6 is an example of adjusting the angle of the reflective surface of the first reflective member of Figure 1.

[0024] Figures 7 (A) and 7 (B) are graphs showing the data of the diffraction MTF (Modulation Transfer Function) of the optical system of Figures 1 and 2.

[0025] Figure 8 is a graph showing the aberration characteristics of the optical system of Figure 1.

[0026] Figure 9 is a graph showing the aberration characteristics of the optical system of Figure 2.

[0027] Figures 10 (A) and (B) are graphs showing relative illumination according to the field height of the image sensors of Figures 1 and 2.

[0028] FIG. 11 is a configuration diagram of an optical system and a camera module according to a second embodiment of the invention.

[0029] Figure 12 is a diagram of the optical system configuration in the near-field mode of Figure 11.

[0030] Figure 13 is a table showing lens data of the optical system of Figure 11.

[0031] Figure 14 is an example of the aspherical coefficients of the lenses of the optical system of Figure 11.

[0032] Figures 15 (A) and (B) are graphs showing the data of the diffraction MTF (Modulation Transfer Function) of the optical system of Figures 11 and 12.

[0033] Figure 16 is a graph showing the aberration characteristics of the optical system of Figure 11.

[0034] Figure 17 is a graph showing the aberration characteristics of the optical system of Figure 12.

[0035] Figures 18 (A) and (B) are graphs showing relative illumination according to the field height of the image sensors of Figures 11 and 12.

[0036] FIG. 19 is a configuration diagram of an optical system and a camera module according to a third embodiment of the invention.

[0037] FIG. 20 is a diagram showing the configuration of the optical system in the near-field mode of FIG. 19.

[0038] Figure 21 is a table showing lens data of the optical system of Figure 19.

[0039] Figure 22 is an example of the aspherical coefficients of the lenses of the optical system of Figure 19.

[0040] (A) and (B) of FIG. 23 are graphs showing the data of the diffraction MTF (Modulation Transfer Function) of the optical system of FIG. 19 and FIG. 20.

[0041] Figure 24 is a graph showing the aberration characteristics of the optical system of Figure 19.

[0042] Figure 25 is a graph showing the aberration characteristics of the optical system of Figure 20.

[0043] (A) and (B) of FIG. 26 are graphs showing relative illumination according to the field height of the image sensors of FIG. 19 and FIG. 20.

[0044] FIG. 27 is a perspective view of a mobile terminal with a camera module applied according to an embodiment of the invention.

[0045] FIG. 28 is a perspective view of a movable body having a camera module according to an embodiment of the invention.

[0046] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. The technical concept of the present invention is not limited to some of the described embodiments but can be implemented in various different forms, and within the scope of the technical concept of the present invention, one or more of the components among the embodiments may be selectively combined or substituted. Furthermore, terms used in the embodiments of the present invention (including technical and scientific terms) may be interpreted in a meaning generally understood by those skilled in the art to which the present invention belongs, unless explicitly and specifically defined otherwise. Terms used generally, such as those defined in advance, may be interpreted in consideration of their meaning in the context of the relevant technology.

[0047] The terms used in the embodiments of the present invention are intended to describe the embodiments and are not intended to limit the present invention. In this specification, the singular form may include the plural form unless specifically stated otherwise in the text, and when described as "at least one of A and B and C (or more than one)," it may include one or more of all combinations that can be formed from A, B, and C. Furthermore, in describing the components of the embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc., may be used. These terms are intended only to distinguish the component from other components and are not to limit the essence, order, or sequence of the component. Also, when it is stated that a component is 'connected,' 'coupled,' or 'connected' to another component, this may include not only cases where the component is directly connected, coupled, or connected to the other component, but also cases where it is 'connected,' 'coupled,' or 'connected' due to another component located between the component and the other component. Furthermore, when described as being formed or placed "above or below" each component, "above" or "below" includes not only cases where two components are in direct contact with each other, but also cases where one or more other components are formed or placed between the two components. Additionally, when expressed as "above or below," it may include the meaning of a downward direction as well as an upward direction relative to a single component.

[0048] In the description of the invention, "object side surface" may refer to a surface of the lens facing the object side with respect to the optical axis (OA), and "sensor side surface" may refer to a surface of the lens facing the imaging surface (image sensor) with respect to the optical axis. That one surface of the lens is convex may refer to a shape that is convex in the optical axis or paraxial region, and that one surface of the lens is concave may refer to a shape that is concave in the optical axis or paraxial region. The radius of curvature, center thickness, and spacing between lenses listed in the table of lens data refer to values ​​in the optical axis, and the unit is mm. The vertical direction may refer to a direction perpendicular to the optical axis, and the end of the lens or lens surface may refer to 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 paraxial region refers to a very narrow region near the optical axis, and is a region where the distance of a ray from the optical axis (OA) is almost zero. In the following description, the concave or convex shape of the lens surface is described in terms of the optical axis and may also include the paraxial region.

[0049]

[0050] FIGS. 1, 11, and 19 are configuration diagrams of an optical system and a camera module according to embodiments of the invention. Referring to FIGS. 1, 11, and 19, the optical system (1000) or the camera module may include a plurality of lenses and a plurality of reflective members. The plurality of reflective members includes a first reflective member (P1) and a second reflective member (M1, P2) spaced apart in the direction of a second optical axis (OA2). The first reflective member (P1) reflects or refracts light incident along the first optical axis (OA1) in the direction of a second optical axis (OA2) that is orthogonal to the first optical axis (OA1). The second reflective member (M1, P2) reflects or refracts light incident along the second optical axis (OA1) in the direction of an optical axis parallel to the first optical axis (OA1). The second reflective member (M1, P2) can reflect or refract light incident on the second optical axis (OA2) toward the upper surface (Image surface) of the image sensor (190).

[0051] The first reflective member (P1) is a prism or a mirror, and may be provided as a prism, for example. The second reflective member (M1, P2) may be a prism or a mirror. The optical system (1000) may be provided as a folded optical system. The number of lenses in the optical system (1000), excluding the reflective members (P1, M1, P2), may be 5 or more or 7 or less. The number of lenses in the optical system (1000) may be 6 or less. There may be 2 or more reflective members (P1, M1, P2) within the optical system (1000). The number of lenses placed between the first reflective member (P1) and an object may be more than 1 or 3 or less. The number of lenses placed between the first reflective member (P1) and the second reflective members (M1, P2) may be more than 3 or 5 or less. The number of lenses placed between the first reflective member (P1) and the second reflective member (M1, P2) may be more than 1 and less than or equal to 3 times the number of lenses placed between the first reflective member (P1) and the object.

[0052] The optical system (1000) can operate in a focusing mode from infinity to near distance by moving a first lens group (LG1) placed between the first reflective member (P1) and an object, or a lens(s) placed between the first and second reflective members, in the direction of the optical axis (OA). When the lens(s) placed between the first and second reflective members are moved in the direction of the second optical axis (OA2), one or more lenses may be moved.

[0053] At least one or two of the lenses disposed between the first reflective member (P1) and the second reflective member (M1, P2) may be provided with a structure in which one or both ends of the effective area are cut. Here, the cut portion may be one or both ends of the first axis (OA1) of the lens. That is, one or both ends of the effective area of ​​a lens with a relatively long effective length may be cut. Accordingly, the cut lens may have an effective length in the third direction (Z) that is smaller than the effective length in the second direction (Y). By reducing the effective length in the third direction of the lenses disposed between the first reflective member (P1) and the second reflective member (M1, P2), the height in the third direction (Z) of the optical system (1000) and the camera module may be reduced. The third direction (Z) is a direction orthogonal to the first and second directions (X, Y) and is the thickness direction of the portable device.

[0054]

[0055] The AF function can move at least one or all of the lenses between the first reflective member (P1) and the second reflective member (M1, P2) in the direction of the second optical axis (OA2). Accordingly, the optical system can provide a foldable tele-optical system. Additionally, the OIS function can be implemented by tilting at least one of the first and second reflective members. As another example, the OIS function can be implemented by shifting a substrate having an image sensor (192). The lenses 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.

[0056]

[0057] The power of the first lens group (LG1) has a positive value. Additionally, the power of the first lens (101, 111, 121) closest to the object has a positive value. Accordingly, the first lens group (LG1) and the first lens (101, 111, 121) can refract the incident light to the entire area of ​​the incident surface (PS1) of the first reflective member (P1). The power of the last lens (106, 116, 126) closest to the image sensor (190) has a negative value. The last lens (106, 116, 126) can refract the incident light to the entire area of ​​the image sensor (190) through the second reflective member (M1, P2). Accordingly, the resolution can be improved by utilizing the refractive power and positive and negative focal lengths of each lens.

[0058] The effective length of the first lens (101, 111, 121) may be the largest among the lenses in the optical system (1000). Accordingly, the first lens (101, 111, 121) can improve the amount of incident light. In addition, at least two of the lenses in the optical system (1000) may have a refractive index of 1.6 or higher. Thus, chromatic dispersion by the lenses in the optical system (1000) can be controlled. The F-number of the optical system (1000) can provide brightness of 2.0 or higher. The first object-side surface (S1) of the first lens (101, 111, 121) may have a convex shape toward the object. The convex first object-side surface (S1) can increase the amount of incident light of the first lens group (LG1). The object-side fifth surface (S1) of the third lens (103, 113, 123) closest to the first reflective member (P1) may have a convex shape toward the object. The convex object-side fifth surface (S5) can prevent a reduction in the incident light amount of the second lens group (LG2). Accordingly, the optical system (1000) can increase the incident light amount, provide good optical performance in the center and periphery of the field of view (FOV), and improve thermal compensation, chromatic aberration, and distortion aberration. The first lens (101, 111, 121) may be made of plastic or glass. If the first lens (101, 111, 121) is made of glass, deformation of the first lens (101, 111, 121) due to external heat can be prevented. In addition, if the first lens (101, 111, 121) is made of glass, external impact or damage to the lens surface can be prevented. That is, the glass lens can block external exposure of the plastic lens and protect the lenses from external heat or impact.

[0059] Each of the plurality of lenses may include an effective region and an ineffective region. The effective region may be an area through which light incident on each of the lenses passes. That is, the effective region may be an area of ​​effective diameter or effective length where the incident light is refracted to realize optical characteristics. The ineffective region may be positioned around the periphery of the effective region. The end of the effective region may be defined as an edge or a tip. The ineffective region may be an area where effective light is not incident on the plurality of lenses. That is, the ineffective region may be an area unrelated to the optical characteristics. Additionally, the tip of the ineffective region may be an area fixed to a barrel (not shown), etc., that accommodates the lenses.

[0060]

[0061] 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 passed through the plurality of lenses (100) sequentially. The image sensor (190) may be any one of a CCD (Charge Coupled Device), CMOS (Complementary Metal Oxide Semiconductor), CPD (Charge Priming Device), or CID (Charge Injection Device), and may include a device capable of detecting incident light. The image sensor (190) may be an RGB (Red, Green, Blue) sensor for acquiring a color image. Additionally, when the image sensor (190) is arranged in a plurality, it may include an RGB image sensor and a monochrome image sensor.

[0062] 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 placed between the first and second reflective members. The optical system (1000) may include an optical filter (192) positioned between the second reflective member (M1, P2) and the image sensor (190). The optical filter (192) may be positioned between the last lens (106, 116, 126) and the image sensor (190). The optical filter (192) may be positioned between the lens closest to the sensor side among the plurality of lenses and the image sensor (190). For example, if the optical system (100) has six lenses, the optical filter (192) may be positioned between the last lens, the sixth lens (106, 116, 126), and the image sensor (190).

[0063] 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. If 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.

[0064] The optical system (1000) according to the embodiment may include an aperture stop (ST). The aperture stop (ST) may be a stopper that controls the amount of light incident on the optical system (1000). For example, the aperture stop (ST) may be placed around the object side or sensor side of the third lens (103, 113, 123) or the fourth lens (104, 114, 124). The field of view (FOV) of the optical system (1000) may be 100 degrees or less, for example, greater than 10 degrees, for example, in the range of 15 to 50 degrees, for example, in the range of 15 to 40 degrees. The F-number (F#) of the optical system (1000) may be 2.5 or more, for example, in the range of 2.5 ≤ F# ≤ 5, and may provide a bright image when it is 3 or less. Additionally, F# can be smaller than the entrance pupil size (EPD). Thus, the optical system (1000) can have a slim size, control the incident light, and have enhanced optical characteristics within the angle of view range.

[0065]

[0066] Hereinafter, an optical system according to embodiments will be described in detail. FIGS. 1 to 10 are drawings illustrating an optical system of a first embodiment. Referring to FIGS. 1 to 4, in the first embodiment of the invention, the optical system (1000) may include a first lens (101), a second lens (102), a first reflective member (P1), third to sixth lenses (103-106), and a second reflective member (M1) arranged from an object toward a sensor. The lenses positioned on the object side of the first reflective member (P1) may be defined as a first lens group (LG1). The lenses positioned between the first reflective member (P1) and the second reflective member (M1) may be defined as a second lens group (LG2). The number of lenses in the first lens group (LG1) may be greater than 1 and less than or equal to 3. The number of lenses in the second lens group (LG2) may be more than 2 and less than or equal to 5. The optical system (1000) may be 7 or fewer, for example, 6 or fewer.

[0067] The first lens (101) and the second lens (102) are sequentially arranged along a first optical axis (OA1) between an object and a first reflective member (P1), and the third to sixth lenses (103, 104, 105, 106) are sequentially arranged along a second optical axis (OA2) between the first reflective member (P1) and the second reflective member (M1).

[0068] The first and second lenses (101, 102) can be defined as the first lens group (LG1), and the third to sixth lenses (103-106) can be defined as the second lens group (LG2). Each of the first to sixth lenses (101-106) 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, satisfying the condition FLG2 < FLG1. The first lens group (LG1) may be fixed in position according to the operation mode, and the second lens group (LG2) may be variable in position according to the operation mode.

[0069]

[0070] The first lens (101) may have a positive (+) or negative (-) refractive power on the first optical axis (OA1), and preferably may have a positive (+) refractive power. The first lens (101) may be made of plastic or glass. On the first optical axis (OA1), the first surface (S1) on the object side of the first lens (101) may have a convex shape, and the second surface (S2) on the sensor side may have a concave shape. That is, the first lens (101) may have a meniscus shape that is convex toward the object on the first optical axis (OA1). Since the first lens (101) has a meniscus shape that is convex toward the object side, it can improve the amount of incident light. 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, where L1 is the first lens (101) and represents the conic constant (K) and aspherical coefficients from the 4th to the 10th order. Alternatively, the first lens (101) may have a meniscus shape that is convex toward the first reflective member (P1). Alternatively, the first lens (101) may have a shape that is convex on both sides. Alternatively, the first lens (101) may have a shape that is concave on both sides. The effective length (Clear aperture) of the first lens (101) may be the largest among the effective lengths of the first to sixth lenses (101-106). The first surface (S1) of the first lens (101) may be the largest among the lens surfaces (S1-S12) of the first to sixth lenses (101-106). Accordingly, the incident light amount of the first lens (101) can be improved. The effective length (Clear aperture) of the first lens (101) is the diameter of the effective area and is twice the semi-aperture. The effective length (Clear aperture) of each lens is the average of the effective lengths of the object-side and sensor-side of each lens.

[0071]

[0072] The second lens (102) may have a positive (+) or negative (-) refractive power on the first optical axis (OA1). The second lens (102) may have a negative (-) refractive power. The second lens (102) may correct aberrations occurring in the first lens (101). The second lens (102) may include plastic or glass materials. For example, the second lens (102) may be provided with a plastic material. On the first optical axis (OA1), the object-side third surface (S3) of the second lens (102) 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 meniscus shape that is convex toward the object on the second optical axis (OA). Alternatively, the third surface (S3) on the second optical axis (OA2) may have a convex shape, and the fourth surface (S4) may have a convex shape. Alternatively, the third and fourth surfaces (S3, S4) may both have a concave shape. Alternatively, the second lens (102) may have a meniscus shape that is convex toward the first reflective member (P1).

[0073] At least one or all 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, where L2 is the second lens (102) and represents the conic constant (K) and aspherical coefficients from the 4th to the 10th order. The center distance between the first lens (101) and the second lens (102) is 0.5 mm or less, which can reduce the loss of light passing through the first and second lenses (101, 102) and suppress the increase in the optical axis distance (TD1) of the first lens group (LG1).

[0074]

[0075] The first reflective member (P1) is positioned between the second lens (102) and the third lens (103). The first reflective member (P1) is positioned 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) in the direction of the second optical axis (OA2) which is orthogonal to the first optical axis (OA1). The first reflective member (P1) has a triangular prism shape and may be provided in a glass or plastic material. The optical axes (OA) of the lenses can be divided into first and second optical axes (OA1, OA2) that are orthogonal to each other. The first reflective member (P1) includes an incident surface (PS1), a reflective surface (PS0), 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 gap (MG1) between the incident surface (PS1) of the first reflective member (P1) and the second lens (102) may be larger than the center gap between the first and second lenses (101, 102).

[0076]

[0077] As shown in FIGS. 1 and 2, the center gap (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 infinity to a near-field mode, and the near-field mode can be 50 cm. When at infinity, the center gap (D1) between the first reflective member (P1) and the third lens (103) can be larger than the center thickness of the first lens (101), for example, larger than the center thickness of the second and third lenses (102, 103). When in a short-range focusing mode, the center gap (D1) between the first reflective member (P1) and the third lens (103) may be reduced compared to the gap in the infinity mode and may be smaller than the center thickness of the second and third lenses (102, 103), for example, may be smaller than the center thickness of the first lens (101).

[0078]

[0079] The third lens (103) may have a positive (+) or negative (-) refractive power on the second optical axis (OA2), and preferably may have a positive (+) refractive power. The third lens (103) may be made of plastic or glass material. On the second optical axis (OA2), the object-side fifth surface (S5) of the third lens (103) may have a convex shape, and the sensor-side sixth surface (S6) may have a concave shape. That is, the third lens (103) may have a convex meniscus shape toward the object or the first reflective member (P1) on the second optical axis (OA2). Alternatively, the third lens (103) may have a convex shape on both sides. Alternatively, the fifth and sixth surfaces (S5, S6) may both have a concave shape. Alternatively, the third lens (103) may have a meniscus shape that is convex toward the sensor. 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, where L3 is the third lens (103) and represents the conic constant (K) and aspherical coefficients from the 4th to the 10th order.

[0080]

[0081] The fourth lens (104) may have a positive (+) or negative (-) refractive power on the second optical axis (OA2). The fourth lens (104) may have a negative (-) refractive power. The fourth lens (104) may include plastic or glass materials. 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 corrected. On the second optical axis (OA2), the object-side seventh surface (S7) of the fourth lens (104) may have a convex shape, and the sensor-side eighth surface (S8) may have a concave shape. That is, the fourth lens (104) may have a meniscus shape that is convex toward the object on the second optical axis (OA2). Alternatively, the fourth lens (104) may have a shape that is convex on both sides. Alternatively, the fourth lens (104) may have a meniscus shape that is convex toward the sensor. Alternatively, the fourth lens (104) may have a shape that is concave on both sides. At least one or all of the seventh surface (S7) and the eighth surface (S8) may be aspherical, and the conic constant (K) and aspherical coefficients from the 4th to the 12th order are provided as in FIG. 4, where L4 is the fourth lens (104). The center distance between the third lens (103) and the fourth lens (104) is 0.5 mm or less, which can reduce the loss of light passing through the third and fourth lenses (103, 104) and reduce the optical axis distance (TD2) of the second lens group (LG2).

[0082]

[0083] The fifth lens (105) may have a positive (+) or negative (-) refractive power on the second optical axis (OA2). The fifth lens (105) is the n-1th lens and may have a positive refractive power. The fifth lens (105) may include plastic or glass material. For example, the fifth lens (105) may be provided with plastic material.

[0084] On the second optical axis (OA2), the ninth surface (S9) on the object side of the fifth lens (105) may have a convex shape, and the tenth surface (S10) on the sensor side may have a concave shape. That is, the fifth lens (105) may have a meniscus shape that is convex toward the object on the second optical axis (OA2). Alternatively, the fifth lens (105) may have a meniscus shape that is convex toward the sensor side. 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, where L5 is the fifth lens (105), L5S1 is the ninth surface, and L5S2 is the tenth surface.

[0085] The fifth lens (105) may have a minimum effective length among the effective lengths of the lenses. For example, the effective length of the ninth surface (S9) of the fifth lens (105) may be the smallest among the lens surfaces. The maximum effective length of the lenses may be greater than 1 time and less than 3 times the minimum effective length, for example, greater than 1 time and less than 3 times. The first surface (S1) of the first lens (101) may be at least 1.5 times the effective length of the ninth surface (S9) of the fifth lens (105), for example, in the range of 1.5 times to 2.5 times.

[0086]

[0087] The sixth lens (106) may have a positive (+) or negative (-) refractive power on the optical axis (OA). The sixth lens (106) is the nth lens and may have a refractive power with the opposite sign to the (n-1)th lens, for example, a negative refractive power. The sixth lens (106) may be made of plastic or glass material. For example, the sixth lens (106) may be made of plastic material. Since the signs of the refractive powers of the fifth and sixth lenses (105, 106) are opposite to each other, chromatic aberrations occurring in the two lenses can be mutually corrected.

[0088]

[0089] On the second optical axis (OA2), the object-side 11th surface (S11) of the sixth lens (106) may have a concave shape, and the sensor-side 12th surface (S12) may have a convex shape. That is, the sixth lens (106) may have a convex meniscus shape toward the sensor side or the second reflective member (M1) on the second optical axis (OA2). Alternatively, the sixth lens (106) may have a convex meniscus shape toward the object. Alternatively, the sixth lens (106) may have a concave or convex shape on both sides. At least one or both of the 11th surface (S11) and the 12th surface (S12) may be aspherical, and the aspherical coefficient is provided as in FIG. 4, where L6 is the sixth lens (106), L6S1 is the 11th surface, and L6S2 is the 12th surface. Since the sixth lens (106) has a convex meniscus shape toward the sensor side or the second reflective member (M1), the sixth lens (106) can irradiate light to the entire area of ​​the second reflective member (M1). Accordingly, light reflected through the second reflective member (M1) can be irradiated to the center and periphery of the image sensor (190). Therefore, the optical system (1000) according to the embodiment can have enhanced optical characteristics even in the center and periphery of the field of view (FOV).

[0090]

[0091] The second reflective member (M1) may be a prism or a mirror, for example, a mirror. The second reflective member (M1) has a reflective surface (MS1), and the reflective surface (MS1) may be inclined at an angle of 45 degrees with respect to the second optical axis (OA2). In the lens data of FIG. 3, Air represents the gap (D1) between the exit surface (PS2) of the first reflective member (P1) and the third lens (103), and the gap between the area of ​​the second reflective member (M1) and the filter (192). The gap (D1) represents a variable distance. Also, in the lens data of FIG. 3, the value of the center thickness of the second reflective member (M1) is the sum of the light paths passing through the second optical axis (OA2) and the axis orthogonal thereto.

[0092] The light reflected through the second reflective member (M1) 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 location further away from the object with respect to the second optical axis (OA2).

[0093]

[0094] The center thickness and edge thickness of the above lenses are as follows. The center thickness of the first to sixth lenses (101-106) is CT1-CT6 and the edge thickness is ET1-ET6, and 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 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 regions of each lens.

[0095] Condition 1: CT2 < CT1 Condition 2: CT1 < CT3

[0096] Condition 3: CT5 < CT4 Condition 4: CT5 < CT6

[0097] Condition 5: ET1 < CT2 < ET2 < CT1 Condition 6: ET5 < ET3 < CT4 < ET6 < ET4

[0098] Condition 7: (CT5+CT6) < BFL

[0099]

[0100] The center thickness (CT3, CT4, CT6) of the third, fourth, and sixth lenses (103, 104, 106) may be thicker than the thickness of the other lenses, and the average thickness of the third, fourth, and sixth lenses (103, 104, 106) may be greater than 1.2 mm. The second lens (102) has the minimum center thickness among the lenses (101-106) and may have a center thickness of 0.8 mm or less, for example, in the range of 0.4 mm to 0.8 mm. Among the lenses, the number of lenses with a center thickness of 0.8 mm or more may be greater than the number of lenses with a center thickness of less than 0.8 mm. Accordingly, the optical system (1000) can control the incident light and may have improved aberration characteristics and resolution.

[0101]

[0102] The center gap between the second lens (102) and the first reflective member (P1) is MG1, and the second optical axis gap between the sixth lens (106) and the reflective surface (MS1) of the second reflective member (M1) is MG2. The condition MG1 < MG2 can be satisfied. The center gap between the third lens (103) and the first reflective member (P1) is D1, and the gap (D1) can be varied by moving the second lens group (LG2) in the direction of the second optical axis (OA2), and can be 0.5 mm or more, for example, in the range of 0.5 mm to 2.5 mm. Since the second lens group (LG2) is moved, objects from a long distance (e.g., infinity) to a short distance (e.g., 50 cm) can be captured. The above gap (D1) may be larger than the center gap between the fourth and fifth lenses (104, 105) in infinity mode and smaller than the center gap between the fourth and fifth lenses (104, 105) in near mode. By moving the second lens group (LG2), the center gap (D2, see FIG. 3) between the area of ​​the sixth lens (106) and the second reflective member (M2) may be varied.

[0103]

[0104] The radii of curvature of the above lenses are as follows. 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 L6R1, It can be defined as L6R2. The above radii of curvature may satisfy at least one of the following conditions to improve the aberration characteristics of the optical system.

[0105] Condition 1: L1R1 < L1R2 Condition 2: L2R2 < L1R2*2 < L2R1

[0106] Condition 3: L3R1 < L1R1 < L3R2 Condition 4: L4R2 < L4R1 < L1R2

[0107] Condition 5: 1 < L5R2 / L5R1 < 2 Condition 6: L5R2 < |L6R1|< |L6R2|

[0108] Condition 7: L2R2 < |L6R2| < L2R1

[0109] In terms of the absolute values ​​of the radii of curvature of each lens surface, the third surface (S3) of the second lens (102) may be the maximum among the lens surfaces, and the eighth surface (S8) of the fourth lens (104) may be the minimum among the lens surfaces. By setting the radii of curvature of each lens in this way, good optical performance can be provided at the focal length of each lens.

[0110]

[0111] The effective lengths of the first to sixth lenses (101-106) can be defined as CA1-CA8, and the effective length (CA1) of the first lens (101) may have the maximum effective length among the lenses and may be 6 mm or more. The effective length (CA5) of the fifth lens (105) may be the minimum among the lenses. The effective lengths of the first and second surfaces (S1, S2) of the first lens (101) can be defined as CA11 and CA12, the effective lengths of the third and fourth surfaces (S3, S4) of the second lens (102) can be defined as CA21 and CA22, the effective lengths of the fifth and sixth surfaces (S5, S6) of the third lens (103) can be defined as CA31 and CA32, the effective lengths of the seventh and eighth surfaces (S7, S8) of the fourth lens (104) can be defined as CA41 and CA42, the effective lengths of the ninth and tenth surfaces (S9, S10) of the fifth lens (105) can be defined as CA51 and CA52, and the effective lengths of the eleventh and twelfth surfaces (S11, S12) of the sixth lens (106) can be defined as CA61 and CA62. These effective lengths are factors that affect the aberration characteristics of the optical system and can satisfy at least one of the following conditions.

[0112] Condition 1: CA5 < CA3 < CA2 < CA1 Condition 2: CA4 < CA6 < CA3

[0113] Condition 3: CA22 < CA12 < CA11 Condition 4: CA42 < CA41 < CA32 < CA31

[0114] Condition 5: CA61 < CA51 < CA62 <CA31

[0115] The effective length (CA11) of the first surface (S1) of the first lens (101) is provided to be 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 sixth lens (106) and the maximum effective length can be set to 2 mm or more.

[0116] Among the first to sixth lenses (101-106), 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, the effective length of the second to sixth lenses (102-106) may be smaller than the diagonal length of the image sensor (190). The effective length of the first to sixth lenses (101-106) may be smaller than the diagonal length of the image sensor (190). For example, the effective length of the second to twelfth planes (S2-S12) may be smaller than the effective diagonal length of the image sensor (190).

[0117]

[0118] The number of lenses with a refractive index greater than 1.6 may be two or more, and the number of lenses with a refractive index less than 1.6 may be three or more. Among the plastic lenses in the above lenses, the second and sixth lenses (102, 106) have a refractive index greater than 1.60 and can refract incident light to the entire area of ​​the first and second reflective members (P1, M1). That is, the refractive index of the incident-side lenses (102, 106) of both reflective members (P1, M1) may be greater than 1.6. In the above optical system, there are two or more lenses with an Abbe number greater than 45, for example, the first, third, and fifth lenses (101, 103, 105). By setting the refractive index and Abbe number of each of these lenses, the effect of chromatic aberration can be controlled.

[0119] If the refractive indices of each of the above lenses (101-106) are Nd1, Nd2, Nd3, Nd4, Nd5, Nd6 and the Abbe numbers of each of the above lenses (101-106) are Vd1, Vd2, Vd3, Vd4, Vd5, Vd6, then at least one of the following conditions may be satisfied.

[0120] Condition 1: Nd1 < Nd2 Condition 2: 1.5 < Nd1,Nd3,Nd4,Nd5 < 1.6

[0121] Condition 3: 1.6 < Nd2, Nd6 < 2.0 Condition 4: Vd2 < Vd1, Vd3

[0122] Condition 5: Vd4,Vd6 < Vd5 Condition 6: 35 <Ave_Ad < 45

[0123] Condition 7: 1.5 <Ave_Nd < 1.8

[0124] Ave_Ad is the average of the Abbe numbers of the first to sixth lenses, and if condition 6 is satisfied, the effect of aberration can be reduced. Ave_Nd is the average of the refractive indices of the first to sixth lenses, and if condition 7 is satisfied, the effect of aberration can be reduced. Depending on these refractive indices and Abbe numbers, the optical system (1000) can have improved chromatic aberration control characteristics.

[0125] When the focal lengths of each lens (101-106) are defined as F1, F2, F3, F4, F5, and F6, the following conditions can be satisfied.

[0126] Condition 1: F1 < |F2| Condition 2: F3 < F1

[0127] Condition 3: F3+|F4| < F5 Condition 4: F1 < F5 < |F6|

[0128] The lens with the largest absolute value of the focal lengths of the lenses is the sixth lens (106), and can satisfy a range of 35mm or more, for example, a range of 35mm to 70mm or a range of 40mm to 65mm.

[0129]

[0130] 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 reflective surface (PS0) of the first reflective member (P1) and the optical axis distance (T3) from the reflective surface (MS1) of the second reflective member (M1) to the center of the image sensor (190). The second optical axis distance (OA2) (T2) from the reflective surface (PS0) of the first reflective member (P1) to the reflective surface (MS1) of the second reflective member (M1) 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 (192), and is the sum of the distances (T1, T2, T3). Since the image sensor (190) is positioned parallel to the first direction (X), the image sensor (190) and the first reflective member (P1) may not overlap in the first direction (X).

[0131] As shown in FIG. 5, the second reflective member (M1) can reflect incident light toward an object. Accordingly, the optical filter (192) and the image sensor (190) can be positioned closer to the object than the second reflective member (M1). Since the optical filter (192) and the image sensor (190) are positioned toward the object side of the second reflective member (M1), the height of the third direction (Z) of the optical system can be reduced.

[0132] As shown in FIG. 6, the inclination angle (R1) of the reflective surface (PS0) of the first reflective member (P1) may be less than 45 degrees with respect to the axis (X1) perpendicular to the first optical axis (OA1), for example, in the 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 axis (X1) in the direction toward the object, and the optical filter (192) and the image sensor (190) are not parallel to the axis (X1) and may overlap with the first reflective member (P1) in the first direction (X).

[0133]

[0134] Figures 7 (A) and 7 (B) are graphs showing the diffraction modulation transfer function (MTF) of the optical systems of Figures 1 and 2, representing the modulation of luminance according to spatial frequency. Figure 8 is a graph showing the aberration characteristics of the optical system of Figure 1, and Figure 9 is a graph showing the aberration characteristics of the optical system of Figure 2. Referring to Figures 8 and 9, the graphs show the longitudinal spherical aberration, astigmatic field curves, and distortion measured from left to right in the aberration graph of the optical system. The X-axis may represent the focal length (mm) and distortion (%), and the Y-axis may represent the height of the image. In addition, the graph for spherical aberration is for light in the wavelength bands of approximately 470 nm, approximately 555 nm, approximately 610 nm, and approximately 650 nm, and the graph for astigmatism and distortion aberration is for light in the wavelength band of 555 nm.

[0135] Figure 10 (A) is a graph showing relative illumination according to the relative sensor height (relative field height) of the optical system of Figure 1, and Figure 10 (B) is a graph showing relative illumination according to the relative sensor height of the optical system of Figure 2. As shown in Figures 10 (A) and (B), it can be seen that the relative illumination is highest at the center (0.0) field (field) of the image sensor and also appears to be 50% or higher at the end (1.0) field.

[0136] The optical system (1000) according to the first embodiment has improved resolution and can have good optical performance not only at the center of the field of view (FOV) but also at the periphery. The lens system of the embodiment according to the present invention can have spherical aberration, astigmatism, distortion, chromatic aberration, and coma aberration all well corrected by configuring 7 or fewer lenses, for example, 6 lenses.

[0137]

[0138] FIGS. 11 to 18 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. Referring to FIGS. 11 to 14, in the second embodiment of the invention, the optical system (1000) may include a first lens (111), a second lens (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.

[0139] The first and second lenses (111, 112) are positioned on the object side of the first reflective member (P1) and can be defined as the first lens group (LG1). The third to sixth lenses (113-116) are positioned between the first and second reflective members (P1, P2) and can be defined as the second lens group (LG2). The number of lenses in the first lens group (LG1) may be greater than 1 and less than or equal to 3. The number of lenses in the second lens group (LG2) may be greater than 2 and less than or equal to 5. The optical system (1000) may have 7 lenses or fewer, for example, 6 lenses or fewer.

[0140] The first lens (111) and the second lens (112) are sequentially arranged along the first optical axis (OA1) between the object and the first reflective member (P1), and the third to sixth lenses (113, 114, 115, 116) 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 sixth lenses (111-116) may have an object-side surface and a sensor-side surface. The refractive power (FLG1) of the first lens group (LG1) may have a positive value, and the refractive power (FLG2) of the second lens group (LG2) may have a positive value, satisfying the condition: FLG2 < FLG1. The first lens group (LG1) is fixed in position according to the operation mode, and the second lens group (LG2) can be varied in position according to the operation mode.

[0141]

[0142] The first lens (111) may have a positive (+) refractive power on the first optical axis (OA1). The first lens (111) may be made of plastic or glass. On the first optical axis (OA1), the first surface (S1) on the object side of the first lens (111) may have a convex shape, and the second surface (S2) on the sensor side may have a concave shape. That is, the first lens (111) may have a meniscus shape that is convex toward the object on the first optical axis (OA1). Since the first lens (111) has a meniscus shape that is convex toward the object side, it can improve the amount of incident light. 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. 14, where L1 is the first lens (111) and represents the conic constant (K) and aspherical coefficients from the 4th to the 10th order. 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 from the first lens (111) can be improved.

[0143] The second lens (112) may have a negative (-) refractive power on the first optical axis (OA1). The second lens (112) may correct aberrations occurring in the first lens (111). The second lens (112) may be made of plastic material. 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. At least one or both of the third surface (S3) and the fourth surface (S4) of the second lens (112) may be aspherical. The aspherical coefficients of the third surface (S3) and the fourth surface (S4) of the second lens (112) are provided as shown in FIG. 14, where L2 is the second lens (112) and represents the conic constant (K) and aspherical coefficients from the 4th to the 10th order. The center distance between the first lens (111) and the second lens (112) may be 0.5 mm or more, for example, in the range of 0.5 mm to 1.2 mm.

[0144]

[0145] The first reflective member (P1) reflects or refracts light incident on the first optical axis (OA1) through the first lens group (LG1) in the direction of the second optical axis (OA2) which is orthogonal to the first optical axis (OA1). The first reflective member (P1) has a triangular prism shape and may be provided in a glass or plastic material. 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 gap (MG1) between the incident surface (PS1) of the first reflective member (P1) and the second lens (112) may be larger than the center gap between the first and second lenses (111, 112).

[0146]

[0147] As shown in FIGS. 11 and 12, the center gap (D1) between the first reflective member (P1) and the third lens (113) can be varied by the second lens group (LG2). The second lens group (LG2) can be moved from infinity to a near-range mode, and the near-range mode can be 50 cm. When at infinity, the center gap (D1) between the first reflective member (P1) and the third lens (113) can be larger than the center thickness of the first lens (111), for example, larger than the center thickness of the second and third lenses (112, 113). When in a near-range focusing mode, the center gap (D1) between the first reflective member (P1) and the third lens (113) can be reduced compared to the gap in the infinity mode and can be larger than the center thickness of the second and third lenses (112, 113). The above center spacing (D1) may be at least 1.5 mm and at most 3 mm.

[0148]

[0149] The third lens (113) may have a positive (+) refractive power on the second optical axis (OA2). The third lens (113) may be made of plastic material. On the second optical axis (OA2), 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 concave shape. That is, the third lens (113) may have a meniscus shape that is convex toward the object or the first reflective member (P1) on the second optical axis (OA2). At least one or both of the fifth surface (S5) and the sixth surface (S6) of the third lens (113) may be aspherical. The aspherical coefficients of the 5th and 6th surfaces (S5, S6) are provided as shown in FIG. 14, where L3 is the 3rd lens (113) and represents the conic constant (K) and aspherical coefficients from the 4th to the 10th order.

[0150]

[0151] The fourth lens (114) may have a negative (-) refractive power on the second optical axis (OA2). The fourth lens (114) may be made of plastic. Since the signs of the refractive powers of the third and fourth lenses (113, 114) are opposite to each other, chromatic aberrations occurring in the two lenses can be mutually corrected. On the second optical axis (OA2), the object-side seventh surface (S7) of the fourth lens (114) may have a convex shape, and the sensor-side eighth surface (S8) may have a concave shape. That is, the fourth lens (114) may have a meniscus shape that is convex toward the object on the second optical axis (OA2). At least one or all of the 7th surface (S7) and the 8th surface (S8) may be aspherical, and the conic constant (K) and aspherical coefficients from the 4th to the 12th order are provided as in FIG. 14, and L4 is the 4th lens (114). The center distance between the 3rd lens (113) and the 4th lens (114) is 0.5 mm or less, which can reduce the loss of light passing through the 3rd and 4th lenses (113, 114) and reduce the optical axis distance (TD2) of the 2nd lens group (LG2).

[0152]

[0153] The fifth lens (115) may have a positive refractive power on the second optical axis (OA2). The fifth lens (115) may be provided with a plastic material. On the second optical axis (OA2), 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. That is, the fifth lens (115) may have a meniscus shape that is convex toward the object on the second optical axis (OA2). At least one or both of the ninth surface (S9) and the tenth surface (S10) of the fifth lens (115) may be aspherical, and the aspherical coefficient is provided as in FIG. 14, where L5 is the fifth lens (115), L5S1 is the ninth surface, and L5S2 is the tenth surface.

[0154] The center thickness of the fourth and fifth lenses (114, 115) may be greater than the center thickness of the other lenses. At least one of the fifth and sixth lenses (115, 116) may have a minimum effective length among the effective lengths of the lenses. For example, the ninth surface (S9) of the fifth lens (115) may be the smallest among the lens surfaces. The maximum effective length of the lenses may be greater than 1 time and less than 3 times the minimum effective length, for example, greater than 1 time and less than 3 times. The first surface (S1) of the first lens (111) may be at least 1.5 times the effective length of the ninth surface (S9) of the fifth lens (115), for example, in the range of 1.5 times to 2.5 times.

[0155] The sixth lens (116) may have a negative refractive power on the optical axis (OA). The sixth lens (116) may be made of plastic material. Since the signs of the refractive powers of the fifth and sixth lenses (115, 116) are opposite to each other, chromatic aberrations occurring in the two lenses can be mutually corrected. On the second optical axis (OA2), the object-side 11th surface (S11) of the sixth lens (116) may have a concave shape, and the sensor-side 12th surface (S12) may have a convex shape. That is, the sixth lens (116) may have a convex meniscus shape toward the sensor side or the second reflective member (P2) on the second optical axis (OA2). At least one or both of the above 11th surface (S11) and the above 12th surface (S12) may be aspherical, and the aspherical coefficient is provided as in FIG. 14, L6 is the 6th lens (116), L6S1 is the 11th surface, and L6S2 is the 12th surface.

[0156] Since the sixth lens (116) has a convex meniscus shape toward the sensor side or the second reflective member (P2), light can be irradiated to the entire area of ​​the second reflective member (P2). Accordingly, 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 enhanced optical characteristics even in the center and periphery of the field of view (FOV).

[0157]

[0158] The second reflective member (P2) may be a prism or a mirror, for example, a prism. The second reflective member (P2) has an incident surface (PS5), a reflective surface (PS4), and an exit surface (PS6), and the reflective surface (PS4) may be inclined at an angle of 45 degrees with respect to the second optical axis (OA2). In the lens data of FIG. 13, Air represents the gap (D1) between the incident surface (PS5) of the first reflective member (P1) and the third lens (113), and the gap between the exit surface (PS6) of the second reflective member (P2) and the filter (192). The gap (D1) represents a variable distance.

[0159] 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 location further away from the object with respect to the second optical axis (OA2).

[0160] The center thickness and edge thickness of the above lenses are as follows.

[0161] Condition 1: CT2 < CT1 Condition 2: CT1 < CT3

[0162] Condition 3: CT5 < CT4 Condition 4: CT5 < CT6

[0163] Condition 5: ET1 < CT2 < ET2 < CT1 Condition 6: ET5 < ET3 < ET6 < CT4 < ET4

[0164] Condition 7: (CT5+CT6) < BFL

[0165] The center thickness (CT3, CT4) of the third and fourth lenses (113, 114) may be thicker than the thickness of the other lenses, and the average thickness of the third and fourth lenses (113, 114) may be greater than 1.2 mm. The second lens (112) has the minimum center thickness among the lenses (111-116) and may have a center thickness of 0.8 mm or less, for example, in the range of 0.4 mm to 0.8 mm. Among the lenses, the number of lenses with a center thickness greater than 0.8 mm may be greater than the number of lenses with a center thickness of 0.8 mm or less. Accordingly, the optical system (1000) can control the incident light and can have improved aberration characteristics and resolution.

[0166]

[0167] The center gap between the second lens (112) and the first reflective member (P1) is MG1, and the second optical axis gap between the sixth lens (116) and the reflective surface (PS4) of the second reflective member (P2) is MG2. The condition MG2 < MG1 can be satisfied. The center gap between the third lens (113) and the first reflective member (P1) is D1, and the gap (D1) can be varied by moving the second lens group (LG2) in the direction of the second optical axis (OA2), and can be 1mm or more, for example, in the range of 1mm to 4mm. Since the second lens group (LG2) is moved, objects from a long distance (e.g., infinity) to a short distance (e.g., 50cm) can be captured. The above gap (D1) may be larger than the center gap between the fourth and fifth lenses (114, 115) in infinity mode and larger than the center gap between the fourth and fifth lenses (114, 115) in near mode. By moving the second lens group (LG2), the center gap (D2, see FIG. 13) between the area of ​​the sixth lens (116) and the second reflective member (M2) may be varied.

[0168] The radii of curvature of the above lenses are as follows. The above radii of curvature may satisfy at least one of the following conditions to improve the aberration characteristics of the optical system.

[0169] Condition 1: L1R1 < L1R2 Condition 2: L2R2 < L1R2*2 < L2R1

[0170] Condition 3: L3R1 < L1R1 < L3R2 Condition 4: L4R2 < L4R1 < L1R2

[0171] Condition 5: 1 < L5R2 / L5R1 < 4 Condition 6: |L6R1| < L5R2 < |L6R2|

[0172] Condition 7: L2R2 < |L6R2| < L2R1

[0173]

[0174] In terms of the absolute values ​​of the radii of curvature of each lens surface, the third surface (S3) of the second lens (112) may be the maximum among the lens surfaces, and the eighth surface (S8) of the fourth lens (114) may be the minimum among the lens surfaces. By setting the radii of curvature of each lens in this way, good optical performance can be provided at the focal length of each lens.

[0175] The effective length of the first lens (111) may have the maximum effective length among the lenses and may be 6 mm or more. The effective length (CA5) of the fifth lens (115) may be the minimum among the lenses. The effective lengths (CA11, CA12, CA21, CA22) of the lens surfaces of the first and second lenses (111, 112) and the effective lengths (CA31, CA32, CA41, CA42, CA51, CA52, CA61, CA62) of the lens surfaces of the third to sixth lenses (113-116) are factors that affect the aberration characteristics of the optical system and may satisfy at least one of the following conditions.

[0176] Condition 1: CA5 < CA4 < CA3 < CA2 < CA1 Condition 2: 0.5 < CA5 / CA6 < 1.5

[0177] Condition 3: CA22 < CA12 < CA11 Condition 4: CA42 < CA41 < CA32 < CA31

[0178] Condition 5: CA51 < CA62 < CA61 < CA52 <CA31

[0179] The effective length (CA11) of the first surface (S1) of the first lens (111) is provided to be 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 sixth lens (116) and the maximum effective length can be set to 2 mm or more. 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, the effective length of the second to sixth lenses (112-116) may be smaller than the diagonal length of the image sensor (190). The effective length of the first to sixth lenses (111-116) may be smaller than the diagonal length of the image sensor (190). For example, the effective length of the second to twelfth planes (S2-S12) may be smaller than the effective diagonal length of the image sensor (190).

[0180]

[0181] The number of lenses with a refractive index greater than 1.6 may be two or more, and the number of lenses with a refractive index less than 1.6 may be three or more. Among the plastic lenses in the above lenses, the second and sixth lenses (112, 116) have a refractive index greater than 1.60 and can refract incident light to the entire area of ​​the first and second reflective members (P1, P2). That is, the refractive index of the incident-side lenses (112, 116) of both reflective members (P1, P2) may be greater than 1.6. In the above optical system, there are two or more lenses with an Abbe number greater than 45, for example, the first, third, and fifth lenses (111, 113, 115). By setting the refractive index and Abbe number of each of these lenses, the effect of chromatic aberration can be controlled. The refractive index (Nd1-Nd6) and Abbe number (Vd1-Vd6) of each of the above lenses (111-116) may satisfy at least one of the following conditions.

[0182] Condition 1: Nd1 < Nd2 Condition 2: 1.5 < Nd1,Nd3,Nd4,Nd5 < 1.6

[0183] Condition 3: 1.6 < Nd2, Nd6 < 2.0 Condition 4: Vd2 < Vd1, Vd3

[0184] Condition 5: Vd4,Vd6 < Vd5 Condition 6: 35 <Ave_Ad < 45

[0185] Condition 7: 1.5 <Ave_Nd < 1.8

[0186] If conditions 6 and 7 are satisfied, the effect of aberration can be reduced. Depending on these refractive indices and Abbe numbers, the optical system (1000) can have improved chromatic aberration control characteristics.

[0187]

[0188] The focal lengths (F1, F2, F3, F4, F5, F6) of each lens (111-116) can satisfy the following conditions.

[0189] Condition 1: F1 < |F2| Condition 2: F3 < F1

[0190] Condition 3: F3+|F4| < |F2| Condition 4: 0.5 < F5 / |F6|< 1.5

[0191] The lens with the largest absolute value of the focal lengths of the lenses is the second lens (116), and can satisfy a range of 20 mm or more, for example, 20 mm to 70 mm or 25 mm to 65 mm.

[0192]

[0193] In FIG. 11, 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 reflective surface (PS0) of the first reflective member (P1) and the optical axis distance (T3) from the reflective surface (MS1) of the second reflective member (P2) to the center of the image sensor (190). The second optical axis distance (OA2) (T2) from the reflective surface (PS0) of the first reflective member (P1) to the reflective surface (PS4) 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 (192), and is the sum of the distances (T1, T2, T3). Since the image sensor (190) is positioned parallel to the first direction (X), the image sensor (190) and the first reflective member (P1) may not overlap in the first direction (X).

[0194] The configuration of FIGS. 11 and FIGS. 12 can be modified as in FIGS. 5 and FIGS. 6. That is, as in FIG. 5, the second reflective member (P2) can reflect incident light toward an object, and the optical filter (192) and image sensor (190) can be positioned closer to the object than the second reflective member (P2). Since the optical filter (192) and image sensor (190) are positioned toward the object side of the second reflective member (P2), the height of the third direction (Z) of the optical system can be reduced. As in FIG. 6, the inclination angle (R1) of the reflective surface (PS0) of the first reflective member (P1) can be less than 45 degrees with respect to the axis (X1) perpendicular to the first optical axis (OA1), for example, in the range of 40 to 44 degrees. That is, the second optical axis (OA2) can 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 axis (X1) in the direction toward the object, and the optical filter (192) and the image sensor (190) are not parallel to the axis (X1) and can overlap with the first reflective member (P1) in the first direction (X).

[0195]

[0196] Figures 15 (A) and (B) are graphs showing the diffraction modulation transfer function (MTF) of the optical systems of Figures 11 and 12, and represent the modulation of luminance according to spatial frequency. Figure 16 is a graph showing the aberration characteristics of the optical system of Figure 11, and Figure 17 is a graph showing the aberration characteristics of the optical system of Figure 12. Referring to Figures 16 and 17, the graphs show the spherical aberration, astigmatism, and distortion aberration measured from left to right in the aberration graph of the optical system. The X-axis may represent the focal length (mm) and distortion (%), and the Y-axis may represent the height of the image. In addition, the graph for spherical aberration is for light in the wavelength bands of approximately 470 nm, approximately 555 nm, approximately 610 nm, and approximately 650 nm, and the graph for astigmatism and distortion aberration is for light in the wavelength band of 555 nm.

[0197] Fig. 18 (A) is a graph showing relative illumination according to the relative sensor height (relative field height) of the optical system of Fig. 11, and Fig. 18 (B) is a graph showing relative illumination according to the relative sensor height of the optical system of Fig. 12. As shown in Fig. 18 (A) and (B), it can be seen that the relative illumination is highest at the center (0.0) field of the image sensor and at the edge (1.0) field, it appears to be 50% or more. The optical system (1000) according to the second embodiment has improved resolution and can have good optical performance not only at the center of the field of view (FOV) but also at the periphery.

[0198]

[0199] FIGS. 19 to 26 are drawings illustrating a third embodiment. In describing the third embodiment, the configuration identical to that of the first embodiment may include the configuration and description of the first embodiment. Referring to FIGS. 19 to 22, in the third embodiment of the invention, the optical system (1000) may include a first lens (121), a second lens (122), a first reflective member (P1), third to sixth lenses (123-126), and a second reflective member (M2) arranged from an object toward a sensor. The first and second lenses (121, 122) are positioned on the object side of the first reflective member (P1) and may be defined as a first lens group (LG1). The third lens (123) can be defined as the second lens group (LG2), and the fourth lens (124) through the sixth lens (126) can be defined as the third lens group (LG3). The third lens group (LG3) can be moved in the direction of the second optical axis (OA2). The first and second lens groups (LG1, LG2) can be fixed in position according to the operation mode.

[0200] The number of lenses in the first lens group (LG1) may be greater than 1 and less than or equal to 3. The number of lenses in the second lens group (LG2) may be less than or equal to 2. The third lens group (LG3) may have more lenses than the first lens group (LG1). The third lens group (LG3) may have more than 2 lenses, for example, 3 to 4 lenses. The optical system (1000) may have 7 lenses or fewer, for example, 6 lenses or fewer. The optical axis distance (TD1) of the first lens group (LG1) may be greater than the optical axis distance (TD2) of the second lens group (LG2) and smaller than the optical axis distance (TD3) of the third lens group (LG3).

[0201] The first lens (121) and the second lens (122) are sequentially arranged along the first optical axis (OA1) between the object and the first reflective member (P1), and the third to sixth lenses (123, 124, 125, 126) are sequentially arranged along the second optical axis (OA2) between the first reflective member (P1) and the second reflective member (M2). The refractive power (FLG1) of the first lens group (LG1) has a positive value, the refractive power (FLG2) of the second lens group (LG2) may have a positive value, and the refractive power (FLG3) of the third lens group (LG3) may have a negative value. The following conditions may be satisfied.

[0202] Condition 1: FLG2 < FLG1 Condition 2: FLG2 < |FLG3| < FLG1

[0203]

[0204] The first lens (121) may have a positive (+) refractive power on the first optical axis (OA1). The first lens (121) may be made of plastic or glass. On the first optical axis (OA1), the first surface (S1) on the object side of the first lens (121) may have a convex shape, and the second surface (S2) on the sensor side may have a concave shape. That is, the first lens (121) may have a meniscus shape that is convex toward the object on the first optical axis (OA1). Since the first lens (121) has a meniscus shape that is convex toward the object side, it can improve the amount of incident light. 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. 22, where L1 is the first lens (121) and represents the conic constant (K) and aspherical coefficients from the 4th to the 10th order. The effective length (Clear aperture) of the first lens (121) may be the largest among the effective lengths of the first to sixth lenses (121-126). The first surface (S1) of the first lens (121) may be the largest among the lens surfaces (S1-S12) of the first to sixth lenses (121-126). Accordingly, the amount of incident light from the first lens (121) can be improved.

[0205] The second lens (122) may have a negative (-) refractive power on the first optical axis (OA1). The second lens (122) may correct aberrations occurring in the first lens (121). The second lens (122) may be made of plastic material. On the first optical axis (OA1), the object-side third surface (S3) of the second lens (122) may have a concave shape, and the sensor-side fourth surface (S4) may have a concave shape. The second lens (122) may have concave shapes on both sides. At least one or both of the third surface (S3) and the fourth surface (S4) of the second lens (122) may be aspherical. The aspherical coefficients of the third surface (S3) and the fourth surface (S4) of the second lens (122) are provided as shown in FIG. 22, where L2 is the second lens (122) and represents the conic constant (K) and aspherical coefficients from the 4th to the 10th order. The center distance between the first lens (121) and the second lens (122) may be 0.9 mm or less, for example, in the range of 0.2 mm to 0.9 mm.

[0206]

[0207] The first reflective member (P1) reflects or refracts light incident on the first optical axis (OA1) through the first lens group (LG1) in the direction of the second optical axis (OA2) which is orthogonal to the first optical axis (OA1). The first reflective member (P1) has a triangular prism shape and may be provided in a glass or plastic material. The incident surface (PS1) of the first reflective member (P1) faces the second lens (122), and the exit surface (PS2) faces the third lens (123). The center gap (MG1) between the incident surface (PS1) of the first reflective member (P1) and the second lens (122) may be larger than the center gap between the first and second lenses (121, 122).

[0208]

[0209] The third lens (123) may have a positive (+) refractive power on the second optical axis (OA2). The third lens (123) may include a plastic material. On the second optical axis (OA2), the object-side fifth surface (S5) of the third lens (123) may have a convex shape, and the sensor-side sixth surface (S6) may have a convex shape. That is, the third lens (123) may have both surfaces convex on the second optical axis (OA2). At least one or both of the fifth surface (S5) and the sixth surface (S6) of the third lens (123) may be aspherical. The aspherical coefficients of the fifth and sixth surfaces (S5, S6) are provided as shown in FIG. 22, where L3 is the third lens (123) and represents the conic constant (K) and aspherical coefficients from the 4th to the 10th order.

[0210]

[0211] The fourth lens (124) may have a negative (-) refractive power on the second optical axis (OA2). The fourth lens (124) may be made of plastic. Since the signs of the refractive powers of the third and fourth lenses (123, 124) are opposite to each other, chromatic aberrations occurring in the two lenses can be mutually corrected. On the second optical axis (OA2), the object-side seventh surface (S7) of the fourth lens (124) may have a convex shape, and the sensor-side eighth surface (S8) may have a concave shape. That is, the fourth lens (124) may have a meniscus shape that is convex toward the object on the second optical axis (OA2). At least one or all of the seventh surface (S7) and the eighth surface (S8) may be aspherical, and the conic constant (K) and aspherical coefficients from the 4th to the 12th order are provided as in FIG. 22, and L4 is the fourth lens (124). The center distance (D1) between the third lens (123) and the fourth lens (124) may be variable.

[0212] As shown in FIGS. 19 and 20, the center gap (D1) between the fourth lens (124) and the third lens (123) can be varied according to the movement of the third lens group (LG3). The third lens group (LG3) can be moved from infinity to a near-range mode, and the near-range mode can be 50 cm. When at infinity, the center gap (D1) between the fourth lens (124) and the third lens (123) can be smaller than the center thickness of the first lens (121), for example, smaller than the center thickness of the first and third lenses (121, 123). When in a near-range focusing mode, the center gap (D1) between the third lens (123) and the fourth lens (124) can be increased compared to the gap in the infinity mode and can be larger than the center thickness of the first and third lenses (121, 123). The above center spacing (D1) may be at least 1.1 mm, for example, in the range of 1.1 mm to 2 mm, and may be at most 3 mm or less.

[0213]

[0214] The fifth lens (125) may have a positive refractive power on the second optical axis (OA2). The fifth lens (125) may be provided with a plastic material. On the second optical axis (OA2), the object-side ninth surface (S9) of the fifth lens (125) may have a convex shape, and the sensor-side tenth surface (S10) may have a convex shape. That is, the fifth lens (125) may have a convex shape on both sides on the second optical axis (OA2). At least one or both of the ninth surface (S9) and the tenth surface (S10) of the fifth lens (125) may be aspherical, and the aspherical coefficient is provided as shown in FIG. 22, where L5 is the fifth lens (125), L5S1 is the ninth surface, and L5S2 is the tenth surface.

[0215]

[0216] The sixth lens (126) may have a negative refractive power on the optical axis (OA). The sixth lens (126) may be made of plastic. Since the signs of the refractive powers of the fifth and sixth lenses (125, 126) are opposite to each other, chromatic aberrations occurring in the two lenses can be mutually corrected. On the second optical axis (OA2), the object-side 11th surface (S11) of the sixth lens (126) may have a concave shape, and the sensor-side 12th surface (S12) may have a concave shape. That is, the sixth lens (126) may have a concave shape on both sides. At least one or both of the 11th surface (S11) and the 12th surface (S12) may be aspherical, and the aspherical coefficient is provided as in FIG. 22, where L6 is the 6th lens (126), L6S1 is the 11th surface, and L6S2 is the 12th surface. Since the 6th lens (126) has a concave shape on both sides, the distance between the 2nd reflective member (M2) and the 6th lens (126) can be reduced. Accordingly, light reflected through the 2nd reflective member (M2) 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).

[0217]

[0218] The center thickness of the third, fifth, and sixth lenses (123, 125, 126) may be greater than the center thickness of the other lenses. The fourth lens (124) may have a minimum effective length among the effective lengths of the lenses. For example, the eighth surface (S8) of the fourth lens (124) may be the smallest among the lens surfaces. The maximum effective length of the lenses may be greater than 1 time and less than 3 times the minimum effective length, for example, greater than 1 time and less than 3 times. The first surface (S1) of the first lens (121) may be at least 1.5 times the effective length of the eighth surface (S8) of the fourth lens (124), for example, in the range of 1.5 times to 2.5 times.

[0219]

[0220] The second reflective member (M2) may be a prism or a mirror, for example, a mirror. The second reflective member (M2) has a reflective surface (MS1), and the reflective surface (MS1) may be inclined at an angle of 45 degrees with respect to the second optical axis (OA2). In the lens data of FIG. 21, Air represents the center gap between the exit surface (PS2) of the first reflective member (P1) and the third lens (123), and the gap between the area of ​​the second reflective member (M2) and the filter (192).

[0221] The center gap (D1) between the object side of the third lens group (LG3) and the third lens (123), and the gap (D2) between the sensor side and the area of ​​the second reflective member (M2) can be varied according to the positional movement of the third lens group (LG3).

[0222] The light reflected through the second reflective member (M2) 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 location further away from the object with respect to the second optical axis (OA2).

[0223]

[0224] The center thickness and edge thickness of the above lenses are as follows.

[0225] Condition 1: CT2 < CT1 Condition 2: CT1 < CT3

[0226] Condition 3; CT4 < CT5 Condition 4: 0.8 < CT5 / CT6 < 1.2

[0227] Condition 5: ET1 < ET2 < ET3 < CT1 Condition 6: ET5 < ET4 < CT5 < ET6

[0228] Condition 7: (CT5+CT6) < BFL

[0229]

[0230] The center thickness (CT3, CT5, CT6) of the third, fifth, and sixth lenses (123, 125, 126) may be thicker than the thickness of the other lenses, and the average thickness of the third, fourth, and fifth lenses (123, 124, 126) may be greater than 1.2 mm. The second lens (122) has the minimum center thickness among the lenses (121-126) and may have a center thickness of 0.8 mm or less, for example, in the range of 0.4 mm to 0.8 mm. Among the lenses, the number of lenses with a center thickness greater than 0.8 mm may be greater than the number of lenses with a center thickness of 0.8 mm or less. Accordingly, the optical system (1000) can control the incident light and may have improved aberration characteristics and resolution.

[0231]

[0232] The center gap between the second lens (122) and the first reflective member (P1) is MG1, and the second optical axis gap between the sixth lens (126) and the reflective surface (MS1) of the second reflective member (M2) is MG2. Condition: MG1 < MG2 can be satisfied. The center gap between the third lens (123) and the fourth lens (124) is D1, and the gap (D1) can be varied by moving the third lens group (LG3) in the direction of the second optical axis (OA2), and can be 0.2mm or more, for example, in the range of 0.2mm to 4mm. Since the third lens group (LG3) is moved, objects from a long distance (e.g., infinity) to a short distance (e.g., 50cm) can be captured. The above gap (D1) may be smaller than the center gap between the fourth and fifth lenses (124, 125) in infinity mode, and larger than the center gap between the fourth and fifth lenses (124, 125) in near mode. By moving the third lens group (LG3), the center gap (D2, see FIG. 21) between the area of ​​the sixth lens (126) and the second reflective member (M2) may be varied.

[0233]

[0234] The radii of curvature of the above lenses are as follows. The above radii of curvature may satisfy at least one of the following conditions to improve the aberration characteristics of the optical system.

[0235] Condition 1: L1R1 < L1R2 Condition 2: L1R2 < L2R2 < |L2R1|

[0236] Condition 3: |L3R2| < L1R2 < |L2R1|*2 < L3R1

[0237] Condition 4: L4R2 < L4R1 < L1R2 Condition 5: 1 < |L5R2| / L5R1 < 4

[0238] Condition 6: L6R1 < L5R1 < L3R1 < |L6R1|

[0239] In terms of the absolute values ​​of the radii of curvature of each lens surface, the 11th surface (S11) of the 6th lens (126) may be the maximum among the lens surfaces, and the 8th surface (S8) of the 4th lens (124) may be the minimum among the lens surfaces. By setting the radii of curvature of each lens in this way, good optical performance can be provided at the focal length of each lens.

[0240]

[0241] The effective length of the first lens (121) may have the maximum effective length among the lenses and may be 6 mm or more. The effective length (CA4) of the fourth lens (124) may be the minimum among the lenses. The effective lengths (CA11, CA12, CA21, CA22) of the lens surfaces of the first and second lenses (121, 122) and the effective lengths (CA31, CA32, CA41, CA42, CA51, CA52, CA61, CA62) of the lens surfaces of the third to sixth lenses (123-126) are factors that affect the aberration characteristics of the optical system and may satisfy at least one of the following conditions.

[0242] Condition 1: CA4 < CA3 < CA2 < CA1 Condition 2: CA4 < CA5 < CA6

[0243] Condition 3: CA22 < CA12 < CA11 Condition 4: CA42 < CA41 < CA32 < CA22

[0244] Condition 5: CA42 < CA61 < CA52 < CA51 < CA62

[0245] The effective length (CA11) of the first surface (S1) of the first lens (121) is provided to be 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 sixth lens (126) and the maximum effective length can be set to 2 mm or more.

[0246] Among the first to sixth lenses (121-126) above, 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, the effective length of the second to sixth lenses (122-126) may be smaller than the diagonal length of the image sensor (190). The effective length of the first to sixth lenses (121-126) may be smaller than the diagonal length of the image sensor (190). For example, the effective length of the second to twelfth planes (S2-S12) may be smaller than the effective diagonal length of the image sensor (190).

[0247]

[0248] The number of lenses with a refractive index greater than 1.6 may be two or fewer, and the number of lenses with a refractive index less than 1.6 may be four or more. Among the plastic lenses in the above lenses, the second lens (122) has a refractive index greater than 1.60 and can refract incident light to the entire area of ​​the first reflective member (P1). In the above optical system, there are two or more lenses with an Abbe number greater than 45, for example, the first, third, fourth, and fifth lenses (121, 123, 124, 125). By setting the refractive index and Abbe number of each of these lenses, the effect of chromatic aberration can be controlled.

[0249] The refractive index (Nd1-Nd6) and Abbe number (Vd1-Vd6) of each of the above lenses (121-126) may satisfy at least one of the following conditions.

[0250] Condition 1: Nd1 < Nd2 Condition 2: 1.5 < Nd1,Nd3,Nd4,Nd5,Nd6 < 1.6

[0251] Condition 3: 1.6 < Nd2 < 2.0 Condition 4: Vd2 < Vd1,Vd3,Vd4

[0252] Condition 5: Vd5,Vd6 < Vd4 Condition 6: 35 <Ave_Ad < 45

[0253] Condition 7: 1.5 <Ave_Nd < 1.8

[0254] If conditions 6 and 7 are satisfied, the effect of aberration can be reduced. Depending on these refractive indices and Abbe numbers, the optical system (1000) can have improved chromatic aberration control characteristics.

[0255] The focal lengths (F1, F2, F3, F4, F5, F6) of each lens (121-126) can satisfy the following conditions.

[0256] Condition 1: F1 < |F2| Condition 2: 0.5 < F3 / F1 < 1.5

[0257] Condition 3: F3+|F4| < |F2| Condition 4: F5 <|F6|

[0258] The lens with the largest absolute value of the focal lengths of the lenses is the second lens (126), and can satisfy a range of 20mm or more, for example, 20mm to 70mm or 20mm to 50mm.

[0259]

[0260] In FIG. 19, 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 (121) to the reflective surface (PS0) of the first reflective member (P1) and the optical axis distance (T3) from the reflective surface (MS1) of the second reflective member (M2) to the center of the image sensor (190). The second optical axis distance (OA2) (T2) from the reflective surface (PS0) of the first reflective member (P1) to the reflective surface (MS1) of the second reflective member (M2) 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 (121) to the image sensor (192), and is the sum of the distances (T1, T2, T3). Since the image sensor (190) is positioned parallel to the first direction (X), the image sensor (190) and the first reflective member (P1) may not overlap in the first direction (X).

[0261] The configuration of FIGS. 19 and FIGS. 20 can be modified as in FIGS. 5 and FIGS. 6. That is, as in FIGS. 5, the second reflective member (M2) can reflect incident light toward an object, and the optical filter (192) and image sensor (190) can be positioned closer to the object than the second reflective member (M2). Since the optical filter (192) and image sensor (190) are positioned toward the object side of the second reflective member (M2), the height of the third direction (Z) of the optical system can be reduced. As in FIGS. 6, the inclination angle (R1) of the reflective surface (PS0) of the first reflective member (P1) can be less than 45 degrees with respect to the axis (X1) perpendicular to the first optical axis (OA1), for example, in the range of 40 degrees to FIGS. 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 axis (X1) in the direction toward the object, and the optical filter (192) and the image sensor (190) are not parallel to the axis (X1) and may overlap with the first reflective member (P1) in the first direction (X).

[0262]

[0263] Figures 23 (A) and (B) are graphs showing the diffraction modulation transfer function (MTF) of the optical systems of Figures 19 and 20, and represent the modulation of luminance according to spatial frequency. Figure 24 is a graph showing the aberration characteristics of the optical system of Figure 19, and Figure 25 is a graph showing the aberration characteristics of the optical system of Figure 20. Referring to Figures 24 and 25, the graphs show the spherical aberration, astigmatism, and distortion aberration measured from left to right in the aberration graph of the optical system. The X-axis may represent the focal length (mm) and distortion (%), and the Y-axis may represent the height of the image. In addition, the graph for spherical aberration is for light in the wavelength bands of approximately 470 nm, approximately 555 nm, approximately 610 nm, and approximately 650 nm, and the graph for astigmatism and distortion aberration is for light in the wavelength band of 555 nm.

[0264] Fig. 26 (A) is a graph showing relative illumination according to the relative sensor height (relative field height) of the optical system of Fig. 11, and Fig. 26 (B) is a graph showing relative illumination according to the relative sensor height of the optical system of Fig. 12. As shown in Fig. 26 (A) and (B), it can be seen that the relative illumination is highest at the center (0.0) field (field) of the image sensor and also appears to be 50% or higher at the edge (1.0) field. The optical system (1000) according to the third embodiment has improved resolution and can have good optical performance not only at the center of the field of view (FOV) but also at the periphery.

[0265]

[0266] The optical system (1000) according to the embodiment disclosed above may satisfy at least one or two of the mathematical formulas described below. Accordingly, the optical system (1000) according to the embodiment may have improved optical characteristics. For example, if the optical system (1000) satisfies the mathematical formula, the optical system (1000) can effectively control aberration characteristics such as chromatic aberration and distortion aberration, and may have good optical performance in the center and periphery of the field of view (FOV). The optical system (1000) may have improved resolution and may have a slimmer and more compact structure. In the following, the unit of the values ​​for the thickness, spacing, effective length, radius of curvature, focal length, etc. of the first to sixth lenses is mm.

[0267] [Mathematical Formula 1] 1 < nLG1

[0268] In mathematical formula 1, nLG1 is the number of lenses of the first lens group (LG1). Preferably, 1 < nLG1 < 3.

[0269] [Mathematical Formula 2] 0.5 < CA11 / PSA11 < 1.7

[0270] CA11 is the effective length of the first surface (S1) of the first lens (101, 111, 121), and PSA11 is the length of the first direction (X) of the incident surface (PS1) of the first reflective member (P1). By satisfying Equation 2, light incident through the first lens (101, 111, 121) can be refracted across the entire area of ​​the incident surface (PS1) of the first reflective member (P1). Equation 2 can satisfy 0.8 < CA11 / PSA11 < 1.5.

[0271] [Mathematical Equation 3] 1 < TD1 / PG1 < 3

[0272] In Equation 3, TD1 is the optical axis distance of the first lens group (LG1), and PG1 is the optical axis spacing between the first lens group (LG1) and the first reflective member (P1). Equation 3 can satisfy 1 < TD1 / PG1 < 2.

[0273] [Mathematical Formula 4] 1 < (CT3+CT4) / (CT1+CT2) < 3

[0274] In Equation 4, the sum of the center thicknesses (CT3, CT4) of the third and fourth lenses may be greater than the sum of the center thicknesses (CT1, CT2) of the first and second lenses. Since Equation 4 is satisfied, the aberration characteristics of the optical system can be improved.

[0275] [Mathematical Equation 5] 0 < L1R1*L1R2

[0276] 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 Equation 5, the first lens can provide a meniscus shape that is convex toward the object and can increase the amount of light incident through the first lens. Preferably, L1R1 < L1R2 can be satisfied.

[0277] [Mathematical Equation 6] 0 < FLG1

[0278] FLG1 is the focal length of the first lens group and can have a positive refractive index. Since it satisfies Equation 6, it can gather 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).

[0279] [Mathematical Equation 7] 0 < TD1 / TD36 < 1

[0280] TD36 is the distance of the second optical axis (OA2) from the center of the object side surface (S5) of the third lens (103, 113, 123) to the sensor side surface (S12) of the sixth lens (106, 116, 126). That is, since TD1 < TD36 is satisfied, the imaging characteristics of the optical system can be improved by the third to sixth lenses, and AF driving can be enabled. Preferably, 0 < TD1 / TD36 < 0.5 can be satisfied.

[0281] [Equation 8] 1 < |FLG1 / FLG2| < 3

[0282] In Equation 8, the absolute value of the focal length of the first lens group may be greater than the absolute value of the focal length of the second lens group. Preferably, 1 < |FLG1 / FLG2| < 2 may be satisfied. Since Equation 8 is satisfied, the aberration characteristics of the optical system can be improved.

[0283] [Mathematical Formula 9] 5 < TTL / TD1 < 20

[0284] In Equation 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 Equation 9 is satisfied, the optical system does not need to be arranged in a long length in either axis direction. Preferably, 8 < TTL / TD1 < 15 can be satisfied.

[0285] [Mathematical Formula 10] 2 < CT_Max / CT_Min < 6

[0286] CT_Max is the maximum center thickness among the lenses, and CT_Min is the minimum center thickness among the lenses. If mathematical formula 10 is satisfied, the optical system (1000) can be reduced in size, for example, by reducing the TTL (total track length). Preferably, 2 < CT_Max / CT_Min < 4 can be satisfied.

[0287]

[0288] [Mathematical Formula 11] 1 < CA11 / CA32 <3

[0289] In Equation 11, the effective length (CA11) of the object side of the first lens is positioned to be larger than the effective length (CA32) of the sensor side of the third lens, so the amount of light incident on the first reflective member (P1) by the first lens (101, 111, 121) can be increased. In addition, since Equation 11 is satisfied, the reduction of the amount of light traveling through the first lens positioned on the incident side of the first reflective member (P1) and the third lens positioned on the exit side of the first reflective member (P1) can be suppressed. Preferably, 1 < CA11 / CA32 < 2 can be satisfied.

[0290] [Mathematical Formula 12] 1 < CA31 / CA62 < 3

[0291] In mathematical formula 12, the influence of the aberration characteristics of the lenses placed between the first and second reflective members can be reduced. That is, by setting the effective length (CA31) of the object side of the third lens (103, 113, 123) placed between the first and second reflective members and the effective length (CA62) of the sensor side of the sixth lens (106, 116, 126), the aberration characteristics of the optical system can be improved. Preferably, 1 < CA31 / CA62 < 2.5 can be satisfied.

[0292] [Mathematical Formula 13] 1 < CA11 / CA62 < 3

[0293] Since mathematical equation 13 is satisfied, the degradation of the chromatic aberration characteristics of the foldable optical system can be prevented. Preferably, 1 < CA11 / CA62 < 2.5 can be satisfied.

[0294] [Mathematical Formula 14] 1 < CA_Max / CA_Min < 3

[0295] 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 Equation 13 is satisfied, the aberration characteristics of the optical system can be improved. Preferably, 1.5 < CA_Max / CA_Min < 2.5 can be satisfied.

[0296]

[0297] [Mathematical Formula 15] 3 < CA1 / CT1 < 9

[0298] Since the effective length (CA1) and center thickness (CT1) of the first lens are satisfied in Equation 15, the incident light can be controlled and the thickness of the first lens group can be provided slimly. Preferably, 4 < CA1 / CT1 < 8 can be satisfied.

[0299] [Mathematical Formula 16] 5 < CA2 / CT2 < 15

[0300] Since the effective length (CA2) and center thickness (CT2) of the second lens are satisfied in Equation 16, the incident light can be controlled and the thickness of the first lens group can be made slim. Preferably, 8 < CA2 / CT2 < 13 can be satisfied.

[0301] [Mathematical Formula 17] 2 < CA3 / CT3 < 5

[0302] Since the effective length (CA3) and center thickness (CT3) of the third lens in Equation 17 are satisfied, light propagating through the second lens group (LG2) can be controlled, and the thickness and height of the second lens group can be provided slimly. Preferably, 2 < CA3 / CT3 < 4 can be satisfied.

[0303] [Mathematical Formula 18] 1 < CA6 / CT6 < 4

[0304] Since the effective length (CA6) and center thickness (CT6) of the sixth lens are satisfied in Equation 18, the path of the outgoing light through the last lens can be controlled and a slim optical system can be provided. Preferably, 2 < CA3 / CT3 < 3.5 can be satisfied.

[0305] [Mathematical Formula 19] 15 < |Vd1 - Vd2| <40

[0306] In mathematical formula 19, the Abbe numbers (Vd1, Vd2) of the first and second lenses can be set to control the chromatic dispersion of light transmitted through the first and second lenses. Preferably, 20 < |Vd1 - Vd2| < 36 can be satisfied.

[0307] [Mathematical Formula 20] 15 < |Vd1 - Vd6| <40

[0308] By setting the Abbe numbers (Vd1, Vd6) of the first and sixth lenses in mathematical formula 20, the chromatic dispersion of light transmitted through the first and sixth lenses can be controlled. Preferably, 20 < |Vd1 - Vd6| < 38 can be satisfied.

[0309]

[0310] [Mathematical Formula 21] 1.5 < Nd1 < Nd2

[0311] In mathematical formula 21, the refractive indices (Nd1, Nd2) at the d-line of the first and second lenses can be set to control the chromatic dispersion of light transmitted through the first and second lenses. Preferably, 1.6 < Nd2 < 2.0 can be satisfied.

[0312] [Mathematical Formula 22] 0 < L1R1 / L2R2 < 1

[0313] In Equation 22, the radius of curvature (L1R1) of the object-side surface of the first lens and the radius of curvature (L1R2) of curvature of the sensor-side surface of the second lens can be set. Since Equation 22 is satisfied, the optical system can control the refractive power of the first and second lenses and provide good optical performance.

[0314] [Mathematical Formula 23] 0 < L1R1 / L3R1 < 4

[0315] In Equation 23, the radius of curvature (L1R1) of the object-side surface of the first lens and the radius of curvature (L3R1) of the object-side surface of the third lens can be set. Since Equation 23 is satisfied, the optical system can control the refractive power of the first and third lenses and provide good optical performance. The first and second embodiments satisfy 1 < L1R1 / L3R1 < 2, and the third embodiment can satisfy 0 < L1R1 / L3R1 < 1.

[0316] [Mathematical Formula 24] 0 < L2R2 / L3R1 < 6

[0317] In Equation 24, the radius of curvature (L2R2) of the sensor side of the second lens and the radius of curvature (L3R1) of the object side of the third lens can be set. Since Equation 24 is satisfied, the optical system can control the refractive power of the second and third lenses placed on the incident and exit sides of the first reflective member (P1) and provide good optical performance. The first and second embodiments satisfy 2 < L2R2 / L3R1 < 6, and the third embodiment can satisfy 0 < L2R2 / L3R1 < 1.

[0318] [Mathematical Equation 25] 0 < |L3R1 / L6R1| < 2

[0319] In Equation 25, the radius of curvature (L3R1) of the object-side surface of the third lens and the radius of curvature (L6R1) of the object-side surface of the sixth lens can be set. Since Equation 25 is satisfied, the optical system can control the refractive power of the first and sixth lenses placed on the incident and exit sides of the first reflective member (P1) and provide good optical performance. Preferably, 0.2 < |L3R1 / L6R1| < 1.5 can be satisfied.

[0320]

[0321] [Mathematical Formula 26] 1 < TTL / T2 < 3

[0322] T2 is the second optical axis distance along the second optical axis (OA2) from the reflective surface of the first reflective member (P1) to the reflective surface of the second reflective member (M1, P2). Since it satisfies Equation 26, the length of the first direction (X) of the optical system can be reduced. Preferably, 1.2 < TTL / T2 < 2 can be satisfied.

[0323] [Mathematical Formula 27] 1 < TTL / F1 < 3

[0324] In Equation 27, the total length of the first and second directions of the optical system and the focal length of the first lens (101, 111, 121) can be set. Since Equation 27 is satisfied, the refractive power of the first lens can be controlled and the TTL can be reduced. Preferably, 1 < TTL / F1 < 2 can be satisfied.

[0325] [Mathematical Equation 28] 0.5 < |F / F1| < 2

[0326] In Equation 28, the total focal length (F) of the optical system and the focal length of the first lens (101, 111, 121) can be set. Since Equation 28 is satisfied, the optical system can improve resolution by controlling the refractive power of the incident light and can improve aberration characteristics such as chromatic aberration and distortion aberration of the optical system. Preferably, 1 ≤ F / F1 < 2 can be satisfied.

[0327] [Mathematical Formula 29] 0 < |F6 / F3| < 7

[0328] In Equation 29, the focal length (F1) of the third lens (103, 113, 123) of the optical system and the focal length (F6) of the sixth lens (106, 116, 126) can be set. Since Equation 29 is satisfied, the refractive power of the third and sixth lenses of the optical system can be controlled and the resolution can be improved. Preferably, the first and second embodiments satisfy 1 < |F6 / F3| < 7, and the third embodiment can satisfy 0 < |F6 / F3| < 1.

[0329] [Mathematical Formula 30] 1 < TTL / F < 2

[0330] In Equation 30, the total length of the first and second directions of the optical system and the total focal length can be set. Since Equation 30 is satisfied, the length of the optical system can be adjusted. Preferably, 1 < TTL / F < 1.8 can be satisfied.

[0331]

[0332] [Mathematical Equation 31] 1 < F1 / L1R1 < 5

[0333] In mathematical formula 31, the focal length of the first lens (101, 111, 121) 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, 121) and adjust the optical axis distance of the first lens group. Preferably, 2 < F1 / L1R1 < 4 can be satisfied.

[0334] [Mathematical Equation 32] 0 < |F2 / L2R2| < 1

[0335] In mathematical formula 32, the focal length of the second lens (102, 112, 122) 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, 122) and adjust the optical axis distance of the first lens group. Preferably, 0.2 |F2 / L2R2| < 0.9 can be satisfied.

[0336] [Mathematical Formula 33] L6R1 < 0

[0337] In Equation 33, the radius of curvature (L6R1) of the object-side surface of the sixth lens (106, 116, 126) can be set to a negative value. Since Equation 33 is satisfied, the sixth lens can refract the incident light to the second reflective member.

[0338] [Mathematical Equation 34] 41° < R1 < 45°

[0339] R1 represents the inclination angle of the reflective surface (PS0) of the first reflective member (P1). The optical system can set the inclination angle of the reflective surface (PS0) of the first reflective member (P1) to less than 45 degrees, thereby positioning the components having the image sensor (190) and the optical filter (192) closer to the object. Accordingly, the height in the direction of the first optical axis (OA1) of the optical system (i.e., Z) can be reduced. Preferably, 42 degrees < R1 < 44 degrees can be satisfied.

[0340] [Mathematical Formula 35] 10 degrees < FOV < 50 degrees

[0341] 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 may be 15 degrees or more, for example, in the range of 15 to 30 degrees.

[0342] [Mathematical Equation 36] 2 < F / EPD < 5

[0343] In Equation 36, the entrance pupil diameter (EPD) and total focal length (F) of the optical system (1000) can be set. When Equation 36 is satisfied, the optical system (1000) can control the overall brightness and can have good optical performance at the center and periphery of the field of view (FOV). Preferably, Equation 36 can satisfy 2.2 < F / EPD < 3.5.

[0344] [Mathematical Formula 37] 5 < TTL / ImgH < 10

[0345] In Equation 37, the total optical axis length (TTL) of the optical system and the length (ImgH) in the diagonal direction from the optical axis of the image sensor (190) can be set. If Equation 60 is satisfied, high image quality and a slim structure can be achieved. Preferably, Equation 37 can satisfy 5 < TTL / ImgH < 9.

[0346] [Equation 38] 1 < BFL / ImgH < 3

[0347] Equation 38 can set the optical axis spacing 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 Equation 38 is satisfied, the optical system (1000) can secure a Back Focal Length (BFL) and minimize the spacing between the last lens and the image sensor (190), thereby having good optical characteristics in the center and periphery of the Field of View (FOV). Preferably, Equation 38 can satisfy 1.5 < BFL / ImgH < 2.5.

[0348] [Mathematical Formula 39] 2mm < ImgH

[0349] In Equation 39, the diagonal length (2*ImgH) of the image sensor (190) can be set to exceed 4mm to provide an optical system with high resolution. Equation 39 can preferably satisfy 3mm < ImgH < 6mm or 3mm ≤ ImgH < 5mm.

[0350] [Mathematical Formula 40] 5mm < F < 40mm

[0351] In mathematical formula 40, the total focal length (F) can be set to fit the optical system, preferably satisfying 10mm < F < 30mm.

[0352] [Mathematical Formula 41] 10mm < TTL < 40mm

[0353] In Equation 41, TTL (Total track length) refers to the distance along the optical axis (OA) from the center of the first surface (S1) of the first lens to the top surface of the image sensor (190). Preferably, Equation 41 can satisfy 15mm < TTL < 35mm.

[0354] [Mathematical Formula 42] 4mm < BFL < 10mm

[0355] Equation 42 can set the Back Focal Length (BFL) of the foldable optical system. That is, the BFL can secure installation space for the second reflective member and the optical filter (192), improve the assembly of components through the gap between the image sensor (190) and the last lens, and improve coupling reliability. Equation 42 can preferably satisfy 5mm < BFL < 9mm.

[0356]

[0357] [Equation 43] 0 < |Max_Distortion| < 3

[0358] In Equation 43, distortion refers to the maximum value of distortion or the maximum value 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). If the optical system (1000) satisfies Equation 43, the optical system (1000) can improve distortion characteristics and set conditions for image processing. Preferably, 0 < |Max_Distortion| < 1.5 can be satisfied.

[0359] Table 1 is a table showing the distortion characteristics from the center (Dist F1) to the end (Dist F11) of the first to third embodiments.

[0360] Sensor height 1st Example 2nd Example 3rd Example Dist(F1) 0.0000.0000.000 Dist(F2) 0.014 0.017 -0.001 Dist(F3) 0.056 0.065 -0.003 Dist(F4) 0.124 0.144 -0.012 Dist(F5) 0.217 0.248 -0.031 Dist(F6) 0.3330.375-0.068Dist(F7)0.4700.522-0.133Dist(F8)0.6260.689-0.235Dist( F9)0.7990.876-0.380Dist(F10)0.9901.091-0.577Dist(F11)1.2041.342-0.827

[0361]

[0362] [Mathematical Formula 44]

[0363]

[0364] In mathematical equation 44, Z represents Sag, which can mean the distance in the direction of the optical axis from any position on the aspherical surface to the vertex of the aspherical surface. Y represents the distance in the direction perpendicular to the optical axis from any position on the aspherical surface to the optical axis. c represents the curvature of the lens, and K represents the conic constant. Additionally, A, B, C, D, E, F, etc., can represent aspheric constants.

[0365]

[0366] The optical system (1000) according to the embodiment can satisfy at least one or two of the mathematical formulas 1 to 43, has improved resolution, and can improve aberration and distortion characteristics. The optical system (1000) can secure a BFL for a foldable optical system and can have good optical performance at the center and periphery of the field of view (FOV). In addition, if the optical system (1000) satisfies at least one of the mathematical formulas 1 to 43, a slimmer and more compact optical system and a camera module having the same can be provided.

[0367] Table 2 is for 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, the focal lengths (F1, F2, F3, F4, F5, F6) of each of the first to sixth lenses, the edge thickness (mm), and the refractive power of each lens group (FLG1, FLG2, FLG3) of the optical system (1000).

[0368] Item Example 1 Example 2 Example 3 F19.600 19.600 19.600 F12 1.328 23.138 16.530 F2 -33.060 -40.832 -31.057 F3 11.675 11.475 17.980 F4 -11.252 -11.170 -9.514 F5 32.860 20.3977.152 F6 -54.572 -20.599 -10.416 FLG 15 1.545 46.438 30.965 FLG 2 30.531 34.719 17.980 FLG 3 -20.606 ET1 0.4020.5230.636ET20.8380.7790.838ET30.9290.9551.260ET41.6531.6961.444ET50.6830.8400.814ET61.5881.3891.908FOV2 0.01720.01820.420EPD7.0007.0006.596BFL6.4147.5966.545ImgH3.5023.6303.501TTL26.00228.27425.939F#2.8002.8002.972

[0369] Table 3 shows the result values ​​for the above-described mathematical formulas 1 to 43 in the optical system (1000) according to the embodiment. Referring to Table 3, it can be seen that the optical system (1000) satisfies at least one, two or more, or three or more of mathematical formulas 1 to 43. Accordingly, the optical system (1000) can improve optical performance and optical characteristics in the center and periphery of the field of view (FOV).

[0370] Mathematical Formula Example 1 Example 2 Example 3 11 < nLG122220.5 < CA11 / PSA11 < 1.7 1.061 1.295 1.06131 < TD1 / PG1 < 31.31 1.668 1.66741 < (CT3+CT4) / (CT1+CT2) < 31.879 1.796 1.29550 < L1R1*L1R2 107.9061 01.106128.48760 < FLG15 1.54546.4383 0.96570 < TD1 / TD36 < 10.25 0.34 0.4581 < |FLG1 / FLG2| < 31.6881.3381.72295 < TTL / TD1 < 2013.22011.30510.375102 < CT_Max / CT_Min < 62.5002.5002.500111< CA11 / CA32 <31.3201.4221.467121 < CA31 / CA62 < 31.4991.4801.051131 < CA11 / CA62 < 31.5061.9501.516141 < CA_Max / CA_Min < 32.0001.9922.000153 < CA1 / CT1 < 96.9346.7114.785165 < CA2 / CT2 < 1510.88911.12310.409172 < CA3 / CT3 < 53.3783.5903.208181 < CA6 / CT6 < 42.8023.0892.8291915 < |Vd1 - Vd2| <4031.75531.75433.1842015 < |Vd1 - Vd6| < 4031.75431.75427.319211.5 < Nd1 < Nd2satisfactionsatisfaction220 < L1R1 / L2R2 < 10.4280.4700.311230 < L1R1 / L3R1 < 41.5911.6020.030240 < L2R2 / L3R1 < 63.7563.9200.125250 < |L3R1 / L6R1| < 20.3170.4390.926261 < TTL / T2 < 31.5711.5921.548271< TTL / F1 < 31.2191.2221.569280.5 < |F / F3| < 21.6791.7081.090290 < |F6 / F3| < 74.6741.7950.579301 < TTL / F < 21.3271.4431.323311 < F1 / L1R1 < 53.1393.3572.615320 < |F2 / L2R2| < 10.4920.8480.37533L6R1 < 0 - 13.471 - 9.803 - 226.4993441 < R1 <4522235>10 < FOV < 5020.01720.01820.420362 < F / EPD < 52.8002.8002.972375 < TTL / ImgH < 107.4247.7887.408381 <BFL / ImgH < 31.8312.0921.869392 < ImgH3.503.633.50405 < F < 4019.60019.60019.6004110 < TTL < 4026.00228.27425.939424 < BFL < 106.4147.5966.545430 < |Max_Distortion| < 31.3421.3420.827.

[0371] FIG. 27 is a diagram showing an example of a mobile terminal to which a camera module according to an embodiment is applied. Referring to FIG. 27, the mobile terminal 1 may include a camera module 10 provided on the rear surface. 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, a zoom function, and an OIS function. The camera module 10 may process a still image or a video frame obtained by an image sensor 190 in a shooting mode or a video call mode. The processed video frame may be displayed on a 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 disposed on the front surface of the mobile terminal 1.

[0372] For example, the camera module (10) may include a first camera module (10A) and a second camera module (10B). In this case, at least one of the first camera module (10A) and the second camera module (10B) may include the 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).

[0373] Additionally, the mobile terminal (1) may further include an autofocus device (31). The autofocus device (31) may include an autofocus function using a laser. The autofocus device (31) may be primarily used in conditions where the autofocus function using the image of the camera module (10) disclosed above is degraded, for example, in close proximity of 10m or less or in a dark environment. The autofocus device (31) may include a light-emitting part including a vertical cavity surface-emitting laser (VCSEL) semiconductor element and a light-receiving part that converts light energy into electrical energy, such as a photodiode. Additionally, 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 operation of the camera of the mobile terminal or by the control of the user.

[0374]

[0375] FIG. 28 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. 28, a vehicle camera system according to an embodiment of the invention includes an image generation unit (11), a first information generation unit (12), a second information generation unit (21, 22, 23, 24), and a control unit (14). The image generation unit (11) may include at least one camera module disposed in the vehicle and may generate a front image of the vehicle or an interior image of the vehicle by photographing the front of the vehicle and / or the driver. The image generation unit (11) may generate an image of the vehicle's surroundings by photographing the vehicle's surroundings in one or more directions as well as the front of the vehicle using the camera module. Here, the front image and the surrounding image may be digital images and may include color images, black and white images, and infrared images. Additionally, the front image and the surrounding image may include still images and video images. The image generation unit (11) provides the driver image, the front image, and the surrounding image to the control unit (14). Next, the first information generating unit (12) may include at least one radar or / and camera placed on the vehicle and generates first detection information by detecting the front of the vehicle. Specifically, the first information generating unit (12) is placed on the vehicle and generates first detection information by detecting the position and speed of vehicles located in front of the vehicle, the presence and location of pedestrians, etc.

[0376] By using the first detection information generated by the first information generation unit (12), the distance between the vehicle and the vehicle in front can be controlled to be maintained at a constant level, and the stability of vehicle operation can be increased in specific cases that are pre-set, such as when the driver wants to change the driving lane of the vehicle or when reverse parking. The first information generation unit (12) provides the first detection information to the control unit (14). The second information generation unit (21, 22, 23, 24) generates second detection information by detecting each side of the vehicle based on the front image generated by the image generation unit (11) and the first detection information generated by the first information generation unit (12). Specifically, the second information generation unit (21, 22, 23, 24) may include at least one radar or / and camera placed on the vehicle, and can detect the position and speed of vehicles located on the side of the vehicle or capture images. Here, the second information generating unit (21, 22, 23, 24) can be positioned at the front corners, side mirrors, and rear center and rear corners of the vehicle, respectively.

[0377] At least one information generating unit among such vehicle camera systems may be equipped with an optical system and a camera module having the same as described in the embodiment(s) disclosed above, and can provide or process information acquired through the front, rear, each side, or corner area of ​​the vehicle to a user to protect the vehicle and objects from autonomous driving or surrounding safety. The optical system of the camera module according to the embodiment of the invention may be mounted in multiple units within the vehicle to comply with safety regulations, enhance autonomous driving functions, and increase convenience. Furthermore, the optical system of the camera module is applied within the vehicle as a component for control, such as a Lane Keeping Assistance System (LKAS), Lane Departure Warning System (LDWS), and Driver Monitoring System (DMS). Such vehicle camera modules can achieve stable optical performance even with changes in ambient temperature and provide cost-competitive modules, thereby ensuring the reliability of vehicle components.

[0378]

[0379] The features, structures, effects, etc. described in the embodiments above are included in at least one embodiment of the present invention and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects, etc. exemplified in each embodiment may be combined or modified and implemented in other embodiments by a person skilled in the art to which the embodiments belong. Therefore, details regarding such combinations and modifications should be interpreted as being included within the scope of the present invention.

[0380] Furthermore, although the invention has been described above with reference to embodiments, this is merely illustrative and does not limit the invention. Those skilled in the art will understand that various modifications and applications not exemplified above are possible within the scope of the essential characteristics of the embodiments. For example, each component specifically shown in the embodiments may be modified and implemented. Differences related to such modifications and applications should be interpreted as being included within the scope of the invention as defined in the appended claims.

Claims

1. First reflective member; A second reflective member spaced apart from the first reflective member; First and second lenses disposed between the first reflective member and the object and sequentially aligned along the first optical axis; and It includes third to sixth lenses sequentially aligned along a second optical axis orthogonal to the first optical axis between the first and second reflective members, and The first lens has a positive refractive power and a meniscus shape that is convex toward an object, and The third lens has positive refractive power and a convex object-side surface, and The above-mentioned sixth lens has negative refractive power and a concave object-side surface, and An optical system having the first lens group having the first and second lenses, wherein the focal length of the first lens group has a positive value.

2. An optical system according to claim 1, wherein a group of lenses having the fourth to sixth lenses among the third to sixth lenses, or all of them, are moved in the direction of the second optical axis.

3. An optical system according to claim 2, wherein the second lens group having the third to sixth lenses has a focal length smaller than the focal length of the first lens group and is moved in the direction of the second optical axis.

4. In claim 2, the third lens has a positive refractive power and is fixed in position, An optical system having the lens group having the fourth to sixth lenses, which has a negative focal length and is moved in the direction of the second optical axis.

5. An optical system according to claim 4, wherein the second lens has negative refractive power and has a shape that is convex on both sides.

6. In claim 5, the third lens has a shape with both sides convex, The above-mentioned sixth lens is an optical system having a concave shape on both sides.

7. In any one of paragraphs 1 through 3, The second lens has negative refractive power and a meniscus shape that is convex toward an object, and The above-mentioned sixth lens is an optical system having a meniscus shape that is convex toward the sensor.

8. In any one of claims 1 to 6, 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 Mathematical formula: 41 < R1 < 45 An optical system satisfying .

9. In any one of claims 1 to 6, the image sensor converts light reflected from the second reflective member into an electrical signal; and the optical filter disposed between the image sensor and the second reflective member, An optical system in which at least one of the optical filter and the image sensor overlaps with the first reflective member in a direction parallel to the second optical axis.

10. In any one of claims 1 to 6, the optical axis distance from the object side surface of the first lens along the first optical axis and the second optical axis to the upper surface of the image sensor is TTL, and The optical axis distance of the first lens group is TD1, and The focal length of the first lens is F1, and The center gap between the first lens group and the first reflective member is PG1, and Mathematical formula: 1 < TTL / F1 < 3 Mathematical formula: 5 < TTL / TD1 < 20 Mathematical formula: 1 < TD1 / PG1 < 3 An optical system satisfying .

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