Optical system, sensor system, and lidar device

Abstract

The optical system disclosed in an embodiment of the present invention comprises: a first lens group having first to third lenses aligned on the optical axis from an object toward a sensing unit; and a second lens group having fourth to sixth lenses disposed between the first lens group and the sensing unit, wherein the power of the first lens group is negative, the power of the second lens group is positive, the first lens has a meniscus shape convex toward the object, the third lens has the smallest effective diameter among the effective diameters of the first to sixth lenses, and at least two of the first to sixth lenses may be aspherical lenses.

Description

Optical systems, sensor systems and lidar devices

[0001] The present invention relates to an optical system and a sensor system having the same. The present invention relates to a receiving optical system for LIDAR (Light detection and ranging) and a device having the same. The present invention relates to a mobile object having a receiving optical system and system for LIDAR.

[0002] ADAS (Advanced Driving Assistance System) is an advanced driver assistance system that assists the driver in driving. It consists of sensing the situation ahead, judging the situation based on the sensed results, and controlling the vehicle's behavior based on the situation judgment. For example, ADAS sensor devices detect a vehicle ahead and recognize lanes. After the target lane, target speed, and forward target are determined, the vehicle's ESC (Electrical Stability Control), EMS (Engine Management System), and MDPS (Motor Driven Power Steering) are controlled. Representative examples of ADAS can be implemented as automatic parking systems, low-speed city driving assistance systems, and blind spot warning systems.

[0003] With the recent surge in interest in autonomous vehicles, demand for LiDAR (Light Detection And Ranging) sensors, a key component of autonomous vehicles, is growing. Currently, LiDAR is used only in high-end, expensive vehicles, but its adoption in general-purpose vehicles is expected to increase as manufacturing costs decline.

[0004] Ultra-small and ultra-light lidar technology can be used not only as a sensor for unmanned mobile devices, but also in satellites and aerospace for observing the Earth's topography and environment, unmanned vehicles, transporters, cranes, and robots used in factories and shipyards, and it is expected to appear in the form of complex or cooperative operation between mobile devices through an integrated approach in the land, aviation, and marine industries. Therefore, the development of an optical system for ultra-small and ultra-light lidar to implement ultra-small and ultra-light lidar is urgent.

[0005] The present invention provides an optical system with improved optical characteristics and a sensor system having the same. The present invention provides a wide-angle optical system and a sensor system having the same. The present invention provides a receiving optical system, a sensor system, and a lidar device having improved thermal compensation characteristics.

[0006] An optical system according to an embodiment of the invention comprises a first lens group having first to third lenses aligned along an optical axis from an object toward a sensing unit; a second lens group having fourth to sixth lenses arranged between the first lens group and the sensing unit, wherein the power of the first lens group is negative, the power of the second lens group is positive, the first lens has a meniscus shape convex toward the object, the third lens has a smallest effective diameter among the effective diameters of the first to sixth lenses, and at least two of the first to sixth lenses may have aspherical lenses.

[0007] According to an embodiment of the invention, the refractive index of the first lens may be greater than 1.7. The second lens may have a refractive index lower than that of the first lens and may be made of glass. The effective diameter of the first lens may be the largest among the effective diameters of the first to sixth lenses. The power of each of the first to third lenses may have a negative value.

[0008] According to an embodiment of the invention, the power of each of the fourth to sixth lenses may have a positive value. The sensor-side surface of the fifth lens may have a convex shape, and the object-side surface of the sixth lens may have a convex shape. The average effective diameter of the object-side surface and the sensor-side surface of the fifth lens is CA5, and the average effective diameter of the object-side surface and the sensor-side surface of the sixth lens is CA6, and the mathematical expression: 0.8 < CA5 / CA6 < 1.2 may be satisfied. The radius of curvature of the sensor-side surface of the fifth lens is L5R2, and the radius of curvature of the object-side surface of the sixth lens is L6R1, and the mathematical expression: 0.8 < |L5R2| / L6R1 < 1.2 may be satisfied.

[0009] According to an embodiment of the invention, the third lens may have a convex meniscus shape toward the object. The horizontal angle of view of the optical system is FOV, the total length of the optical system is TTL, and the mathematical expression: 2 < FOV / TTL < 10 may be satisfied. The average of the absolute values ​​of the focal lengths of the first to sixth lenses is AVER(|F1|:|F6|), and the mathematical expression: 5 < AVER(|F1|:|F6|) < 30 may be satisfied. The focal length of the optical system is F, and the entrance pupil of the optical system is EPD, and the mathematical expression: 0.5 < F / EPD < 1.5 may be satisfied.

[0010] According to an embodiment of the invention, the first to sixth lenses may be made of glass, the third and fourth lenses may be aspherical lenses, and the first, second, fifth, and sixth lenses may be spherical lenses. The optical system may include an optical filter disposed between the sensing unit and the sixth lens, and the angle of view of the optical system may be 110 degrees or more.

[0011] A lidar device according to an embodiment of the invention comprises an optical system having a plurality of lenses, a sensing unit, and an optical filter disposed between the optical system and the sensing unit, wherein the optical system may have an F number of 1 or less and a horizontal angle of view of 110 degrees or more.

[0012] According to an embodiment, improved optical characteristics can be achieved. Specifically, the optical system according to the embodiment can provide a receiving optical system having a wide angle. The receiving optical system of the lidar of the invention can improve light receiving efficiency.

[0013] The optical system of the inventive lidar can have good optical characteristics in a temperature range from low to high temperature. Specifically, a plurality of lenses included in the receiving optical system can have set materials, refractive powers, and refractive indices. Accordingly, when the refractive index of each lens changes due to temperature changes and the focal length of each lens changes as a result, mutual compensation can be made by the aspherical lens and the spherical lens made of glass. In other words, the receiving optical system can effectively perform refractive power distribution in a temperature range from low to high temperature, and can prevent or minimize changes in optical characteristics in a temperature range from low to high temperature. Therefore, the optical system and sensor system according to the embodiment can maintain improved optical characteristics in a variety of temperature ranges.

[0014] The optical system of the inventive lidar may have lenses with set thicknesses, refractive powers, and spacings from adjacent lenses. Accordingly, the optical system and sensor system according to the embodiment may have improved MTF characteristics, aberration control characteristics, resolution characteristics, etc. within a set field of view range, and may exhibit good optical performance in the periphery of the field of view.

[0015] The receiving optical system and sensor system according to the embodiment can satisfy a set field of view and implement excellent optical characteristics through a combination of spherical and aspherical lenses made of glass. As a result, the optical system can provide a vehicle sensor system with improved optical characteristics. Accordingly, the optical system and sensor system can be provided for various applications and devices, and can have excellent optical characteristics even in harsh temperature environments, such as when exposed to the exterior of a vehicle or in the high temperatures of a vehicle interior during the summer.

[0016] Fig. 1 is a side cross-sectional view of the optical system of the lidar according to the first embodiment.

[0017] Figure 2 is a drawing explaining the characteristics of the fifth and sixth lenses of Figure 1.

[0018] Fig. 3 is a table showing lens data of the optical system of Fig. 1.

[0019] Fig. 4 is a table showing the aspherical coefficients of lenses in the optical system of Fig. 1.

[0020] Fig. 5 is a graph showing data of the diffraction MTF (Modulation Transfer Function) of the optical system of Fig. 1.

[0021] Fig. 6 is a graph showing data on the aberration characteristics of the optical system of Fig. 1.

[0022] Figures 7a to 7c are graphs of light aberrations of the optical system of Figure 1.

[0023] Fig. 8 is a side cross-sectional view of the optical system of the lidar according to the second embodiment.

[0024] Fig. 9 is a table showing lens data of the optical system of Fig. 8.

[0025] Fig. 10 is a table showing the aspherical coefficients of lenses in the optical system of Fig. 8.

[0026] Figure 11 is a graph showing the diffraction MTF (Modulation Transfer Function) data of the optical system of Figure 8.

[0027] Fig. 12 is a graph showing data on the aberration characteristics of the optical system of Fig. 8.

[0028] Figures 13a to 13c are graphs of light aberrations of the optical system of Figure 8.

[0029] Figure 14 is a graph comparing the angular resolution according to the angle of view and focal length in an embodiment of the invention and a comparative example.

[0030] FIG. 15 is a drawing for setting the scanning range (FOV) and the angular resolution according to the target distance in a lidar device according to an embodiment of the invention.

[0031] Fig. 16 is a block diagram showing a sensor system having the optical systems of Figs. 1 and 8.

[0032] FIG. 17 is a drawing showing an example of measuring an object in a vehicle having a sensor system of the invention.

[0033] Fig. 18 is a drawing showing an example of surrounding surveillance in a vehicle having a sensor system of the invention.

[0034] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. The technical idea of ​​the present invention is not limited to some of the embodiments described, but can be implemented in various different forms, and one or more of the components between the embodiments can be selectively combined or substituted within the scope of the technical idea of ​​the present invention. In addition, terms (including technical and scientific terms) used in the embodiments of the present invention can be interpreted as having a meaning that can be generally understood by a person having ordinary skill in the technical field to which the present invention belongs, unless explicitly and specifically defined and described, and terms that are commonly used, such as terms defined in a dictionary, can be interpreted in consideration of the contextual meaning of the related technology.

[0035] The terminology used in the embodiments of the present invention is for the purpose of describing the embodiments and is not intended to limit the present invention. In this specification, the singular may also include the plural unless specifically stated in the phrase, and when it is described as “A and (or at least one (or more) of B, C)”, it may include one or more of all combinations that can be combined with A, B, and C. In addition, when describing components of the embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only for distinguishing the components from other components, and are not limited by the nature, order, or sequence of the components. In addition, when it is described that a component is “connected,” “coupled,” or “connected” to another component, it may include not only cases where the component is directly connected, coupled, or connected to the other component, but also cases where the component is “connected,” “coupled,” or “connected” due to another component between the component and the other component. Additionally, when it is described as being formed or arranged "above or below" each component, "above" or "below" includes not only cases where the two components are in direct contact with each other, but also cases where one or more other components are formed or arranged between the two components. Furthermore, when it is expressed as "above" or "below", it can include the meaning of a downward direction as well as an upward direction based on one component.

[0036] In the description of the invention, the "object-side surface" may mean a surface of a lens facing the object side based on the optical axis (OA), and the "sensor-side surface" may mean a surface of a lens facing the imaging surface (surface of the sensing unit) based on the optical axis. The convexity of one surface of the lens may mean a convex shape in the optical axis or the paraxial region, and the concaveness of one surface of the lens may mean a concave shape in the optical axis or the paraxial region. The radius of curvature, center thickness, and optical axis spacing between lenses described in the table for lens data may mean values ​​(unit: mm) in the optical axis. The vertical direction may mean a direction perpendicular to the optical axis, and the end of a lens or lens surface may mean the end of an effective area of ​​a lens through which incident light passes. The size of the effective diameter of the lens surface may have a measurement error of up to ±0.4 mm depending on the measurement method, etc. The above-mentioned near-axis region refers to a very narrow region near the optical axis, and is a region where the distance a light ray falls from the optical axis (OA) is almost 0. Hereinafter, the optical axis may include the center of each lens or a very narrow region near the optical axis.

[0037] In the description of the invention, the center thickness of each lens can be defined as CT1 to CTn from the first lens adjacent to the object to the last lens, and the edge thickness, which is the end of the effective area of ​​each lens, is represented as ET1-ETn. The center spacing between adjacent lenses can be defined as CG1 to CGn from the two lenses adjacent to the object to the center spacing between the lenses adjacent to the image sensor, and the focal lengths from the first lens to the nth lens can be defined as F1 to Fn. The refractive indices from the first lens to the nth lens can be defined as Nd1 to Ndn, and the Abbe number can be defined as Ad1 to Adn. The effective diameters from the first lens to the nth lens can be defined as CA1 to CAn. In addition, the radii of curvature of the object-side surface and the sensor-side surface of each lens can be defined as L1R1 and L1R2 to LnR1 and LnR2 from the first lens to the last lens.

[0038]

[0039] FIG. 1 and FIG. 8 are cross-sectional side views showing an optical system according to an embodiment of the invention.

[0040] Referring to FIGS. 1 and 8, an optical system (100) and a sensor system having the same can be mounted inside or outside a moving vehicle to monitor a driver or sense external objects or lanes. The material of each lens in the optical system (100) can be selected from glass or plastic. The linear expansion coefficient of glass lenses is smaller than that of plastic materials. Therefore, at least one of the lenses of the optical system (100) can be made of glass to suppress changes in the focal imaging position due to temperature changes. However, when the optical system is configured with spherical glass lenses, there is a limit to reducing the number of lenses of the optical system (100), and there is a limit to reducing the size and weight of the optical system (100).

[0041] An optical system (100) of an embodiment of the invention may include a spherical lens and an aspherical lens. Here, the spherical lens is a lens in which at least one or both of the object-side surface and the sensor-side surface of the lens on the optical axis is spherical. The aspherical lens is a lens in which at least one or both of the object-side surface and the sensor-side surface of the lens on the optical axis is aspherical. The optical system (100) may include a spherical glass lens and an aspherical glass lens. In addition, an optical system (100) having an aspherical lens may have a reduced overall length and may be capable of good correction for various aberrations such as spherical aberration and chromatic aberration. In addition, the aspherical lens may minimize distortion in the periphery of the sensing unit (151). The aspherical lens may be injection-molded from glass or plastic.

[0042]

[0043] The optical system (100) may include n lenses, the nth lens may be the last lens adjacent to the sensing unit (151), and the (n-1)th lens may be the lens closest to the last lens. n is an integer greater than or equal to 5, for example, may be in the range of 5 to 7. The ratio of the spherical lens to the aspherical lens in the n lenses may be any one of 4:1, 3:2, 3:3, 4:2, or 4:3. Preferably, the number of spherical lenses may be greater than the number of aspherical lenses. Accordingly, an increase in the price of the optical system (100) may be suppressed. The difference in the number of spherical lenses and the number of aspherical lenses may be 1 to 3.

[0044] In the optical system (100), the first lens (101, 111) closest to the object may be made of glass. The glass material exhibits little change in expansion and contraction due to changes in external temperature, and its surface is not easily scratched, thereby preventing surface damage. Accordingly, in the optical system (100), the first lens (101, 111) on the object side may be a spherical lens, and the nth lens may be arranged as a spherical lens. Since the nth lens in the optical system (100) is arranged as a spherical lens, assembly efficiency may be improved.

[0045] Within the optical system (100), at least two lenses closest to the object can be arranged with glass material. Accordingly, since the rate of contraction and expansion of the lenses adjacent to the outside according to temperature change is smaller than that of the plastic material, deterioration of optical characteristics according to temperature change within the lens barrel can be prevented. In the optical system (100), the last lens (106, 116) closest to the sensing unit (151) can be arranged as a spherical surface made of glass material, and since the rate of contraction and expansion of the last lens (106, 116) according to temperature change is smaller than that of the plastic material, deterioration of optical characteristics according to temperature change within the lens barrel can be prevented.

[0046]

[0047] Each lens of the optical system (100) may have an object-side surface and a sensor-side surface. The lenses may include lenses having an object-side spherical surface and a sensor-side spherical surface, or lenses having an object-side aspherical surface and a sensor-side aspherical surface. The spherical lens and the aspherical lens may be made of glass. Among the lenses of the optical system (100), the lens having the maximum Abbe number may be the second lens (102, 112). A lens surface having a maximum effective diameter within the optical system (100) may be arranged on the first lens (101, 111) closest to the object. The first lens (101, 111) may be made of glass and be a spherical lens. A lens having a minimum effective diameter within the optical system (100) may be arranged between an aperture (ST) and the first lens (101, 111). The effective diameter is an average of the effective diameters of the object-side surface and the sensor-side surface of each lens. Among the lenses between the aperture (ST) and the first lens (101, 111), the lens surface having the smallest effective diameter may be closest to the aperture (ST). In addition, the average effective diameter of the aspherical lens may be smaller than the average effective diameter of the spherical lenses. By adjusting the effective diameter of each lens, the assembling performance of the optical system (100) can be improved.

[0048] Each of the above lenses may include an effective area and an ineffective area. The effective area may be an area through which light incident on each of the lenses passes. That is, the effective area may be defined as an effective area or effective diameter through which the incident light is refracted to implement optical characteristics. The ineffective area may be arranged around the periphery of the effective area. The ineffective area may be an area through which effective light is not incident from the plurality of lenses. That is, the ineffective area may be an area unrelated to the optical characteristics. In addition, an end of the ineffective area may be an area fixed to a lens barrel (not shown) that accommodates the lens.

[0049]

[0050] Within the optical system (100), TTL may be more than 5 times, for example, more than 5 times and less than 15 times, than ImgH (Image height). Within the optical system (100), TTL is the total length of the optical system (100). The TTL (Total track length or total top length) is the distance from the center of the object-side surface of the first lens (101, 111) to the imaging surface of the sensing unit (151) on the optical axis (OA). The ImgH is the distance from the center of the effective area of ​​the sensing unit (151), i.e., the image sensor, to the diagonal end, or half of the maximum diagonal length of the effective area of ​​the sensing unit (151). In addition, the effective diameter of each lens within the optical system (100) may be greater than the diagonal length of the sensing unit (151).

[0051] Within the optical system (100), the effective focal length (EFL) is less than 10 mm and the field of view (FOV) is 80 degrees or more or 120 degrees or more, so that it can be provided as a standard receiving optical system in a vehicle sensor system. For example, the receiving optical system and sensor system according to the embodiment can be applied to a sensing device for an ADAS (Advanced Driving Assistance System) installed inside or outside a vehicle. In the embodiment of the invention, the field of view (FOV) is a horizontal field of view (Horizontal FOV).

[0052]

[0053] The above optical system (100) can satisfy the condition of 3 < TTL / (2*ImgH) < 8. Accordingly, the central thickness of each lens along the optical axis (OA) can be increased and the size of the sensing unit (151) can be reduced, thereby providing a vehicle lens optical system. In addition, temperature compensation can be possible in the temperature range that serves as the temperature reliability evaluation standard for automotive electrical components for use in vehicle cameras, that is, from -45°C to +120°C. The lens must be configured to have heat resistance so that the focus of the lens remains within the set range even when the lens expands or contracts due to temperature changes. The total effective focal length (EFL) can be less than 10 mm and can be configured with lenses made of glass capable of the aforementioned temperature compensation. By shortening the effective focal length of the optical system, a wide angle can be implemented.

[0054] The invention requires a wide-angle optical system to reduce the number of camera modules in a lidar system. This requires a highly efficient projection-type optical system considering the characteristics of the lidar device and the aspect ratio (e.g., 4:3) of the image sensor. This projection type can select a projection model according to the target angular resolution (regular resolution) for each scan range, and the projection type of the invention can apply a horizontal fisheye lens type. As shown in Fig. 14, when the focal length (f) of the optical system increases, the problem of distortion increasing as the angle increases occurs, and when the focal length (f) decreases, the angular resolution increases. In the optical system of the embodiment, when the horizontal half-angle of view (FOV / 2) is greater than 55 degrees, for example, 60 degrees or more, and the focal length (e.g., 2.85 mm) is set, it can have improved resolution at a larger angle of view than the focal length of 3.15 mm of the comparative example, and can have finer resolution at a lower angle of view than the focal length of 2.17 mm or 1.93 mm of the comparative example. The comparative example is an Equi-stance (y=ftheta) model, and can be an Equi-solid (y=sfsin(theta / 2))-conformal, orthographic (y=fsin(theta)) model.

[0055] The above resolution can be set according to the target distance once the sensor specifications and scan range are determined. As shown in Fig. 15, the horizontal angular resolution (c1) and the vertical angular resolution (c2) of an area having a horizontal field of view (Q1), a vertical field of view (Q2), a distance to the target (D2), and a scan height (D1) in a lidar device can be set. In addition, the angular resolution can be adjusted to reduce the difference between the center resolution and the side resolution, which can improve the light receiving efficiency. According to an embodiment of the invention, each resolution may have a resolution of 0.41 deg (0.1 Field) to 0.53 deg (0.6 Field) in a first section where the field of view range is 88 degrees or less, a resolution of 0.53 deg (0.6 Field) to 0.87 deg (0.87 Field) in a second section where the field of view range is 140 degrees or less, and a resolution of 0.87 deg (0.87 Field) to 1.99 deg (1.0 Field) in a third section where the field of view range is 190 degrees or less.

[0056]

[0057] In the optical system (100), the number of lenses having positive (+) refractive power may be equal to or greater than the number of lenses having negative (-) refractive power. The number of lenses having positive (+) refractive power may be 50% or more, for example, 55% or more, of the total number of lenses. The average refractive index of the lenses having negative refractive power may be less than the average refractive index of the lenses having positive refractive power. The dispersion value of the lenses having positive refractive power may be less than the dispersion value of the lenses having negative refractive power. Since the optical system (100) is a mixture of spherical lenses and aspherical lenses made of glass, various aberrations can be corrected, thereby preventing deterioration of optical performance. In addition, in the optical system (100), the number of aspherical lenses may be less than the number of lenses having negative refractive power. Accordingly, various aberrations of the optical system (100) can be corrected, thereby preventing deterioration of optical performance.

[0058]

[0059] The optical system (100) may include an aperture (ST) on the periphery between the lenses. The aperture (ST) may be arranged between the spherical lenses. The lenses arranged closer to the object side than the aperture (ST) may be defined as a first lens group, and the lenses arranged closer to the sensor side than the aperture (ST) may be defined as a second lens group. The power of the first lens group may have negative power, and the power of the second lens group may have positive power. Accordingly, the optical system (100) may correct various aberrations due to the power of the lens groups, achieve desired optical performance, and efficiently configure the system.

[0060]

[0061] The optical system (100) and camera module may have an F number of 1.5 or less. The F number may be in the range of 0.6 to 1.5 or in the range of 0.65 to 0.95. In constructing such a bright optical system, the camera module may include six lenses, and may be miniaturized and achieve good optical performance by using at least one aspherical lens.

[0062] In the optical system (100), the sum of the refractive indices of the lenses may be greater than 7, for example, greater than 8.0, and preferably, in the range of 8.0 to 12.0, and the average of the refractive indices may be in the range of 1.70 to 1.82. The sum of the Abbe numbers of each of the lenses may be greater than 200, for example, in the range of 200 to 350 or 220 to 310, and the average of the Abbe numbers may be less than 50, for example, in the range of 25 to 50. By controlling the refractive indices of the lenses in the optical system (100), it is possible to prevent degradation of optical performance for temperature changes from -45 to 120 degrees and to optimize thermal compensation. In addition, by controlling the Abbe number, it is possible to minimize the deviation of the spot size of incident light, that is, to minimize the spot diagram size.

[0063]

[0064] The sum of the central thicknesses of all lenses within the optical system (100) may be 30 mm or less, for example, in the range of 10 mm to 30 mm or 12 mm to 22 mm, and the average of the central thicknesses of each lens may be 3 mm or less, for example, in the range of 1 mm to 3 mm. The sum of the central spacings between the lenses along the optical axis (OA) may be 12 mm or less, for example, in the range of 5 mm to 12 mm, and may be smaller than the sum of the central thicknesses of the lenses. By adjusting the thickness of each lens within the optical system (100), it is possible to prevent degradation of optical performance for temperature changes from -45 to 120 degrees and to optimize thermal compensation.

[0065] In an optical system according to an embodiment of the invention, the angle of view may be 120 degrees or more, for example, in a range of 120 degrees or more to 250 degrees, preferably, in a range of 150 degrees to 220 degrees. The diagonal length of the sensing unit (151) may be 4 mm or more, for example, in a range of 4 mm to 8 mm or 6.4 mm±1 mm, and may be greater than the sensor height in the vertical direction. The invention can provide a vehicle lidar device that suppresses a change in a focal imaging position due to temperature change by stacking glass lenses and corrects various aberrations by providing an aspherical lens.

[0066]

[0067] The embodiment includes an optical system applied to a lidar device, and the first lens (101, 111) may be provided with a glass material. This is because glass has the advantage of being scratch-resistant and insensitive to external temperature compared to plastic materials. In order to more effectively prevent scratches caused by foreign substances or when placed inside a vehicle, a glass lens may be used as the first lens (101, 111), and the object-side surface of the first lens (101, 111) may have a convex shape to prevent external foreign substances from accumulating. The lidar device can detect the distance, direction, speed, temperature, material distribution, and concentration characteristics to an object when the vehicle is running. Such a lidar device can be used for an advanced driver assistance system (ADAS).

[0068] The optical system (100) according to the embodiment may further include a reflective member (not shown) for changing the path of light. The reflective member may be implemented as a prism that reflects incident light toward the lenses. Hereinafter, the optical system according to the embodiment will be described in detail.

[0069]

[0070] An optical system according to a first embodiment of the invention will be described.

[0071] FIG. 1 is a side cross-sectional view of an optical system of a lidar according to a first embodiment, FIG. 2 is a drawing explaining the characteristics of the fifth lens and the sixth lens of FIG. 1, FIG. 3 is a table showing lens data of the optical system of FIG. 1, FIG. 4 is a table showing aspherical coefficients of lenses in the optical system of FIG. 1, FIG. 5 is a graph showing data of a diffraction MTF (Modulation Transfer Function) of the optical system of FIG. 1, FIG. 6 is a graph showing data on aberration characteristics of the optical system of FIG. 1, and FIGS. 7a to 7c are graphs of light aberrations of the optical system of FIG. 1.

[0072] Referring to FIGS. 1 to 4, the optical system (100) may include first lenses (101) to sixth lenses (106) aligned from the object side toward the sensor side along the optical axis (OA). The first to sixth lenses (101-106) may be defined as a lens unit. The lens unit and the sensor unit (151) may be defined as a camera module, a sensor system, or a lens assembly. The optical system (100) may include an optical filter (153), and the optical filter (153) may be arranged between the last lens and the sensing unit (151).

[0073] Light corresponding to object information can pass through the first lens (101) to the sixth lens (106) and the optical filter (153) and be incident on the sensing unit (151). The aperture (ST) can be arranged around the sensor-side surface of the third lens (103) or the object-side surface of the fourth lens (104).

[0074] The first lens group includes first to third lenses (101, 102, 103) arranged between the aperture (ST) and the object. The second lens group includes fourth to sixth lenses (104-106) arranged between the aperture (ST) and the sensing unit (151). The power of the first lens group may have a negative value, and the power of the second lens group may have a positive value. The focal length of the first lens group is a composite focal length of the first to third lenses (101-103), and the focal length of the second lens group is a composite focal length of the fourth to sixth lenses (104-106). The power is the reciprocal of the focal length.

[0075]

[0076] Each of the first to sixth lenses (101-106) may have positive (+) or negative (-) power on the optical axis (OA). At least one or all of the first to sixth lenses (101-106) may include a plastic material or a glass material, and may be, for example, a glass material.

[0077] The first lens (101) may have positive (+) or negative (-) refractive power, and preferably negative (-) refractive power. The first lens (101) made of glass can reduce changes in the center position and radius of curvature due to temperature changes in the surrounding environment, and can protect the incident side surface of the optical system (100). The first lens (101) is made of glass that is not injection molded. The object-side first surface (S1) of the first lens (101) on the optical axis (OA) may be convex, and the sensor-side second surface (S2) may be concave. The first surface (S1) and the second surface (S2) on the optical axis (OA) may be spherical. The first lens (101) may have a meniscus shape that is convex toward the object side. In contrast, the first surface (S1) may have a concave shape on the optical axis (OA), and the second surface (S2) may have a convex shape. In contrast, the first lens (101) may have a concave shape on both sides. Since the first lens (101) has a convex meniscus shape toward the object, the incident light can be refracted in a direction close to the optical axis (OA), the gap between the first and second lenses (101, 102) can be reduced, and an increase in the effective diameter of the second lens (102) can be suppressed. An increase in the effective diameter of the second lens (102) can be suppressed by the shape of the lens surface of the first lens (101).

[0078] When the refractive index of the first lens (101) is Nd1, the condition of 1.65 < Nd1 or 1.7 < Nd1 < 2 can be satisfied. The refractive index (Nd1) of the first lens (101) can be greater than the refractive index of the second lens (102). When the refractive index (Nd1) of the first lens (101) is less than the condition, the lens surface must be formed to be sharply concave or convex in order to increase the refractive power of the first lens (101). In this case, lens manufacturing is not easy, the lens defect rate increases, and this can cause a decrease in yield.

[0079]

[0080] The second lens (102) may be arranged between the first lens (101) and the third lens (103). The second lens (102) may face the sensor-side surface of the first lens (101) and the object-side surface of the third lens (103). The second lens (102) may have negative (-) refractive power. The second lens (102) may be a spherical lens made of glass. On the optical axis (OA), 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 convex meniscus shape toward the object. On the optical axis (OA), the third and fourth surfaces (S3 and S4) may be spherical. Alternatively, the third surface (S3) may be convex and the fourth surface (S4) may be convex. Alternatively, the second lens (102) may have a convex meniscus shape toward the sensor or a concave shape on both sides.

[0081]

[0082] The third lens (103) may have positive (+) or negative (-) refractive power, and preferably may have negative (-) refractive power. The third lens (103) may include a glass material. The third lens (103) may be an aspherical lens made of glass. On the optical axis (OA), the fifth surface (S5) on the object side of the third lens (103) may be convex, and the sixth surface (S6) on the sensor side may be concave. On the optical axis (OA), the third lens (103) may have a meniscus shape convex toward the object. Alternatively, the third lens (103) may have a concave shape on both sides of the optical axis (OA). Alternatively, the third lens (103) may have a convex meniscus shape toward the sensor side. Alternatively, the third lens (103) may have a convex shape on both sides of the optical axis. At least one or both of the fifth surface (S5) and the sixth surface (S6) are aspherical, and as shown in FIG. 4, the third lens is L3 and has a radius of curvature (Y) of the fifth and sixth surfaces (S5, S6), a conic constant, and an aspherical coefficient from the 4th to the 20th order.

[0083] When the refractive indices of the second and third lenses (102, 103) are Nd2 and Nd3, the condition of Nd2 < Nd3 can be satisfied. When the Abbe number of the second and third lenses (103) is Vd2 and Vd3, the condition of Vd3 < Vd2 can be satisfied. In the specification, the refractive index is the refractive index at the D-line.

[0084] The aperture (ST) may be arranged around the periphery of the sensor-side sixth surface (S6) of the third lens (103) or the object-side seventh surface (S7) of the fourth lens (104). The focal length of the third lens (103) is F3, and since the third lens (103) located on the object-side of the aperture (ST) has negative refractive power (F3 < 0), the third lens (103) can refract incident light away from the optical axis, and the gap between the third lens (103) and the fourth lens (104) may be spaced apart, or the shape of the object-side surface of the fourth lens (104) may be concave. Accordingly, the effective diameter of the fourth lens (104) may be larger than that of the third lens (103). Here, the power of the fourth, fifth, and sixth lenses (104, 105, and 106) arranged on the sensor side of the aperture (ST) can have a positive value, and the optical system can reduce TTL within the angle of view range.

[0085] The effective diameter of the third lens (103) may be smaller than the effective diameters of the second and fourth lenses (102, 104). The effective diameter of the third lens (103) may be the smallest among the effective diameters of the first to sixth lenses (101-106). The effective diameters of the lenses may gradually decrease from the object toward the aperture (ST). The effective diameters of the lenses may gradually increase from the aperture (ST) toward the last lens. That is, the effective diameter from the first lens (101) to the third lens (103) may gradually decrease. The effective diameter from the third lens (103) to the fifth lens (105) may gradually increase. The effective diameter of each lens is the average of the effective diameters of the object-side surface and the sensor-side surface of each lens.

[0086]

[0087] The fourth lens (104) may have positive (+) or negative (-) refractive power, and preferably positive (+) refractive power. The fourth lens (104) may include a glass material. The fourth lens (104) may be an aspherical lens. On the optical axis (OA), the seventh surface (S7) on the object side of the fourth lens (104) may be concave, and the eighth surface (S8) on the sensor side may have a convex shape. The fourth lens (104) may have a meniscus shape that is convex toward the sensor. Alternatively, the fourth lens (104) may have a convex shape on both sides. Alternatively, the fourth lens (104) may have a meniscus shape that is convex toward the object. Alternatively, on the optical axis (OA), the fourth lens (104) may have a concave shape on both sides. At least one or both of the seventh surface (S7) and the eighth surface (S8) are aspherical, and as shown in FIG. 4, the fourth lens is L4 and has a radius of curvature (Y) of the fifth and sixth surfaces (S5, S6), a conic constant, and an aspherical coefficient from the fourth to the twentieth order.

[0088]

[0089] The fifth lens (105) may have positive (+) or negative (-) refractive power, and preferably positive (+) refractive power. The fifth lens (105) may include a glass material. The fifth lens (105) may be a spherical lens. On the optical axis (OA), the ninth surface (S9) on the object side of the fifth lens (105) may be concave, and the tenth surface (S10) on the sensor side may have a convex shape. The fifth lens (105) may have a meniscus shape that is convex toward the sensor. Alternatively, the fifth lens (105) may have a convex shape on both sides. Alternatively, the fifth lens (105) may have a meniscus shape that is convex toward the object. 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) may be spherical.

[0090] The absolute value of the radius of curvature of the ninth surface (S9) of the fifth lens (105) on the optical axis may be greater than the absolute value of the radius of curvature of the tenth surface (S10), and may be the largest among the absolute values ​​of the radii of curvature of the lens surfaces. Accordingly, the difference between the absolute value of the radius of curvature of the ninth surface (S9) of the fifth lens (105) and the absolute value of the radius of curvature of the eighth surface (S8) of the fourth lens (104) may be the largest among the differences in the absolute values ​​of the radii of curvature between the lens surfaces of adjacent lenses. Accordingly, the center spacing (CG4) between the fourth and fifth lenses (104, 105) may be smaller than the center spacings (CG1, CG2, CG3) between the first to fourth lenses (101-104).

[0091] The sixth lens (106) may have positive (+) refractive power. The sixth lens (106) may include a glass material. The sixth lens (106) may be a spherical lens. On the optical axis (OA), the object-side eleventh surface (S11) of the sixth lens (106) may have a convex shape, and the sensor-side twelfth surface (S12) may have a concave shape. The sixth lens (106) may have a convex meniscus shape toward the object. Alternatively, the sixth lens (106) may have a convex meniscus shape toward the sensor. Alternatively, both surfaces of the sixth lens (106) may have convex or concave shapes. At least one or both of the ninth surface (S9) and the tenth surface (S10) are spherical.

[0092] The 11th and 12th surfaces (S11, S12) of the first to sixth lenses (101-106) may be provided without a critical point from the optical axis to the end of the effective area, or may have at least one critical point. Here, the critical point may be a point where the sign of the slope value with respect to the optical axis (OA) and the direction perpendicular to the optical axis (OA) changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the slope value is 0. In addition, the critical point may be a point where the slope value of a tangent passing through the lens surface increases and then decreases, or a point where the slope value decreases and then increases.

[0093] The effective diameter (CA6) of the sixth lens (106) and the effective diameter (CA5) of the fifth lens (105) may have the following conditions.

[0094] Condition: 0.8 < CA5 / CA6 < 1.2

[0095] The difference between the effective diameter (CA6) of the sixth lens (106) and the effective diameter (CA5) of the fifth lens (105) satisfies the following conditions, thereby reducing light loss. The effective diameter of the first lens (106) may be the largest among the lenses. The lens surface with the largest effective diameter among the object-side surfaces of the lenses may be the first surface (S1), and the lens surface with the largest effective diameter among the sensor-side surfaces of the lenses may be the tenth surface (S10). The lens surface with the smallest effective diameter among the object-side surfaces of the lenses may be the fifth surface (S5), and the lens surface with the smallest effective diameter among the sensor-side surfaces of the lenses may be the sixth surface (S6). The effective diameter of the first lens (101) is larger than the effective diameter of the sixth lens (106) closest to the sensing unit (151), and the focal length of the sixth lens (106) is larger than the focal length of the optical system (100), so that an optical system (100) having a small F number and a bright image can be provided.

[0096]

[0097] The radius of curvature of the tenth surface (S10) of the fifth lens (105) is L5R2, and the radius of curvature of the eleventh surface (S11) of the sixth lens (106) is L6R1, and may have the following conditions.

[0098] Condition: 0.8 < |L5R2| / L6R1 < 1.2

[0099] The radius of curvature of the ninth surface (S9) of the fifth lens (105) is L5R1, and the radius of curvature of the twelfth surface (S12) of the sixth lens (106) is L6R2, and may have the following conditions.

[0100] Condition: 0.5 < |L5R1| / L6R2 < 1.5

[0101] The central thicknesses of the fifth lens (105) and the sixth lens (106) are CT5 and CT6, and may have the following conditions.

[0102] Condition: 0.8 < CT5 / CT6 < 1.2

[0103] The edge thicknesses of the fifth lens (105) and the sixth lens (106) are ET5 and ET6, and may have the following conditions.

[0104] Condition: 0.8 < ET5 / ET6 < 1.2

[0105] The refractive indices of the fifth lens (105) and the sixth lens (106) are Nd5 and Nd6, and may have the following conditions.

[0106] Condition: 0.8 < Nd5 / Nd6 < 1.2

[0107] The above 5th and 6th lenses (105, 106) can reduce light loss by satisfying the above conditions.

[0108] Since the first and third lenses (101, 103) have negative power, an optical system with a large angle of view can be provided. The fourth lens (104) to the sixth lens (106) can have positive power, so that the F number can be configured to be 1 or less or less than 1. By controlling the effective diameters of each of the lenses (101-106), the optical system (100) can control the incident light to compensate for the deterioration of the optical characteristics due to resolution and temperature change, improve the chromatic aberration control characteristics, and improve the vignetting characteristics of the optical system (100).

[0109] Since the radius of curvature of the object-side first surface (S1) of the first lens (101) is greater than the radius of curvature of the second surface (S2), distortion of reflected light can be reduced and the depth of field can be further increased, thereby improving image quality under low-light conditions.

[0110]

[0111] The optical system (100) or sensor system may include a sensing unit (151). The sensing unit (151) may detect light that sequentially passes through the lenses. The sensing unit (151) may detect light and convert it into an electrical signal. The sensing unit (151) may obtain various information about the subject. The sensing unit (151) may detect time delay or phase difference information from the incident light, and based on this, may obtain distance information to the subject, position information of the subject, depth image of the subject, etc. To this end, the sensing unit (151) may include a device that may detect incident light, such as an image sensor, for example, a Charge Coupled Device (CCD) or a Complementary Metal Oxide Semiconductor (CMOS). As another example, the sensing unit may include a Time to Digital Converter (TDC). Here, the effective length of the sensing unit (151) is the maximum length in the diagonal direction orthogonal to the optical axis (OA), and here, the lens surface having an effective diameter smaller than the effective length of the sensing unit (151) may be at least one or both of the object-side surface and the sensor-side surface of the third lens (103).

[0112]

[0113] The optical system (100) may include an optical filter (153), and the optical filter (153) may be arranged between the sensing unit (151) and the final lens (106). The optical filter (153) may transmit light, for example, a laser wavelength, reflected from a subject after being emitted from the transmission optical system, and block other wavelengths. The transmitted laser wavelength may be in the range of 890 nm to 960 nm or 940 nm ± 10 nm. As another example, the laser wavelength may be in the range of 1550 nm ± 10 nm. The optical filter (153) may be a bandpass filter.

[0114] The optical filter (153) can perform an operation of passing light of a specific wavelength (e.g., a wavelength range of approximately 800 to 1000 nm) or light belonging to a specific band, and blocking light outside the specific wavelength. The optical filter (153) can actively perform the filtering operation. To this end, the optical filter (153) can include an active device that, in response to an external control signal, passes only light having a specific center wavelength and blocks light of other wavelengths. The control signal provided to the optical filter (153) can include information about the center wavelength of the light to pass through the active device, wherein the center wavelength can correspond to the center wavelength of the light emitted from the transmission optical system. Consequently, the control signal provided to the optical filter (153) is a control signal that matches the center wavelength of the light emitted from the transmission optical system with the center wavelength of the light to pass through the active device of the optical filter (153). Due to the active device included in the optical filter (153), the optical filter (153) can selectively pass only the desired light and block other noise light including natural light. Therefore, the signal-to-noise ratio (S / N) of the lidar system can be increased. As an example of the active device, the optical filter may include a tunable band-pass filter. The tunable band-pass filter may operate in a liquid crystal manner or an acousto-optic manner. The optical filter (153) is a TOF optical system that uses a specific wavelength or a designated wavelength band, and can block light outside the designated wavelength band from being incident on the sensor unit, thereby suppressing the generation of stray light.

[0115] A cover glass (not shown) is placed between the last lens and the sensing unit (151), and protects the upper portion of the sensing unit (151) and can prevent a decrease in the reliability of the sensing unit (151). The cover glass (153) can be placed between the optical filter (153) and the sensing unit (151), and can be removed.

[0116]

[0117] The above aperture (ST) can control the amount of light incident on the optical system (100). The aperture (ST) can be arranged around the seventh surface (S7) of the fourth lens (104). The lens surface (S7) on which the aperture (ST) is arranged can more efficiently control and guide the amount of light of the optical system (100). As in the embodiment, the aperture (ST) can be arranged on the object-side surface of the fourth lens (104). Alternatively, the aperture (ST) can be arranged around the sensor-side surface of the third lens (103). Alternatively, at least one lens selected from the plurality of lenses, for example, the object-side surface or the sensor-side surface of the third lens (103), can function as an aperture.

[0118] The refractive power of the first lens group having the first to third lenses (101-103) may have a negative (-) value. The refractive power of the second lens group having the fourth to sixth lenses (104-106) may have a positive (+) value. The composite refractive power of the first to third lenses (101-103) may have a negative (-) value, and the composite refractive power of the fourth to sixth lenses (104-106) may have a positive (+) value.

[0119]

[0120] As shown in FIG. 2, the Sag value of the sensor-side 10th surface (S10) of the fifth lens (105) is Sag52, and the absolute value of Max_Sag52 may be greater than the center distance (CG5) between the fifth and sixth lenses (105, 106). The Sag value of the object-side 11th surface (S11) of the sixth lens (106) is Sag61, and the absolute value of Max_Sag61 may be smaller than the absolute value of Max_Sag52. The difference between the absolute value of Max_Sag52 and the Max_Sag61 value may be less than 1 mm. Since the edge portion of the sensor-side surface (S10) of the fifth lens (105) has a large Sag value, the fifth lens (105) can refract the light refracted through the fourth lens (104) to the entire area of ​​the sixth lens (106). Here, the maximum Sag value is the height from the straight line perpendicular to the center of each lens surface to the edge, and if each lens surface is located on the object side relative to the straight line, it may have a negative value, and if it is located on the sensor side, it may have a positive value. The Max_Sag52 value of the sensor-side surface (S10) of the fifth lens (105) is a negative value, and the Max_Sag61 value of the object-side surface (S11) of the sixth lens (106) is a positive value.

[0121] A normal line (K2), which is a straight line perpendicular to a tangent line (K1) passing through any point of the sensor-side tenth surface (S10) of the fifth lens (105), may be inclined at a first angle (R1) with respect to the optical axis (OA). When the first angle (R1) is at a maximum, it may be greater than 5 degrees and less than 65 degrees, for example, in a range of 10 to 50 degrees or 30 to 40 degrees. Accordingly, the shape of the fifth lens (105) and the length ratio of the TTL and the sensing unit (151) can be adjusted.

[0122] The normal line, which is a straight line perpendicular to the tangent line passing through any point of the object-side eleventh surface (S11) of the sixth lens (106), can be inclined at a second angle with respect to the optical axis (OA), and when the second angle is the maximum, it can be more than 5 degrees and less than 65 degrees, for example, it can be in the range of 10 degrees to 50 degrees or 30 degrees to 40 degrees. Accordingly, the shape of the fifth lens (105) and the length ratio of the TTL and the sensing unit (151) can be adjusted.

[0123]

[0124] As shown in FIGS. 1 and 2, the center thickness (CT1-CT6) and edge thickness (ET1-ET6) of the first to sixth lenses (101-106) and the center spacing (CG1-CG5) between adjacent two lenses satisfy at least one of the following conditions, and * means multiplication.

[0125] Condition 1: CT1 < CT6 Condition 2: CT2 < CT5

[0126] Condition 3: CT3 < CT4 Condition 4: (CT1+CT2+CT3) < (CT5+CT6)

[0127] Condition 5: CT1 < ET1 < CT4 Condition 6: CT2 < ET2 < CT4

[0128] Condition 7: CG2 < CT1 < CG1 Condition 7: CG4 < CG5 < CG3

[0129] Condition 8: CG3 < CG2 < CT4

[0130] Here, the difference between the maximum center spacing and the minimum center spacing may be 1 mm or more, for example, in the range of 1 mm to 3 mm. Furthermore, by providing the maximum center spacing between the lenses to be smaller than the maximum center thickness of each lens, a receiving optical system with a small center spacing between the lenses can be provided. Furthermore, since the maximum center spacing between the lenses is provided to be larger than the minimum center thickness of each lens, the optical path can be controlled. By controlling the center thickness of these lenses, the sensor system can be slimmed down and thermally compensated for temperature changes from low to high temperatures.

[0131]

[0132] The effective diameters of each lens (101-106) are CA1-CA6, the effective diameters of the first and second surfaces (S1, S2) of the first lens (101) are CA11, CA12, the effective diameters of the third and fourth surfaces (S3, S4) of the second lens (102) are CA21, CA22, the effective diameters of the fifth and sixth surfaces (S5, S6) of the third lens (103) are CA31, CA32, the effective diameters of the seventh and eighth surfaces (S7, S8) of the fourth lens (104) are CA41, CA42, the effective diameters of the ninth and tenth surfaces (S9, S10) of the fifth lens (105) are CA51, CA52, and the effective diameters of the eleventh and twelfth surfaces (S11, S12) of the sixth lens (106) are CA61, CA62. The effective diameter of each lens can satisfy the following conditions.

[0133] Condition 1: CA12 < CA11 < CA12*2 Condition 2: CA3 < CA2 < CA1

[0134] Condition 3: CA3 < CA4 < CA5 Condition 4: CA6 ≤ CA5 < CA1

[0135] Condition 5: 0.8 < CA6 / CA5 < 1.2 Condition 6: 0.8 < CA52 / CA61 < 1.2

[0136] Condition 7: 0.8 < CA51 / CA52 < 1.2 Condition 8: 0.8 < CA61 / CA62 < 1.2

[0137] The effective diameter of each of the first, second, and fourth to sixth lenses (101, 102, 104-106) may be greater than the diagonal length of the effective area of ​​the sensing unit (151). The third lens (103) may be smaller than the diagonal length of the effective area of ​​the sensing unit (151). These lenses can guide incident light to the entire area of ​​the sensing unit (151).

[0138]

[0139] Fig. 3 is an example of lens data of the optical system of the embodiment of Fig. 1. As shown in Fig. 3, the radius of curvature on the optical axis (OA) of the first to sixth lenses (101-106), the center thickness (CT) of the lenses, the center gap (CG) between the lenses, the refractive index at the d-line, the Abbe number, the focal length of each lens, and the size of the effective diameter of each lens surface can be set.

[0140] As shown in FIG. 4, among the lenses of the embodiment of FIG. 1, the lens surfaces (S5, S6, S7, S8) of the third and fourth lenses (103, 104) may include an aspherical surface having a radius of curvature (Y), a conic constant, and a 20th aspherical surface coefficient. For example, an aspherical surface having a 20th aspherical surface coefficient (a non-zero value) as described above can significantly change the aspherical shape of the periphery, thereby effectively compensating for the optical performance of the periphery of the field of view (FOV).

[0141]

[0142] The refractive power (F1-F6) and overall focal length (F) of each lens can satisfy the following conditions.

[0143] Condition 1: │F1│ < │F2│ Condition 2: F4 < │F3│ < │F2│

[0144] Condition 3: 0.5 < F4 / F5 < 1.5 Condition 4: 0.8 < F5 / F6 < 1.2

[0145] Condition 5: F < F5 Condition 6: F < │F1│

[0146] Condition 7: F < BFL

[0147] Here, F is the effective focal length of the optical system, and BFL is the optical axis distance from the last lens, i.e., the sixth lens (106), to the surface of the image sensor, which is the sensor unit (151). Accordingly, the optical system can have improved MTF characteristics, aberration control characteristics, resolution characteristics, etc. in the set field of view range, and can have good optical performance in the periphery of the field of view.

[0148]

[0149] TTL is the optical axis distance from the object side of the first lens (101) to the surface of the sensor unit (151), and FOV is the angle of view of the optical system. TTL and FOV can satisfy the following conditions.

[0150] Condition 1: CA12*2 < TTL < CA12*3

[0151] Condition 2: |F2| < TTL

[0152] Condition 3: 0.1 < TTL / FOV < 0.5

[0153]

[0154] Fig. 5 is a graph showing the diffraction MTF in the optical system of Fig. 1, and is a graph showing the modulation of the luminance according to the spatial frequency. That is, Fig. 5 shows the diffraction MTF at room temperature, and is a graph measuring the luminance ratio according to the defocusing position.

[0155] FIG. 6 is a graph showing the aberration characteristics in the optical system of FIG. 1. In the aberration graph of FIG. 6, astigmatic field curves and distortion are measured from left to right. In FIG. 6, the X-axis may represent the focal length (mm) and the degree of distortion (%), and the Y-axis may represent the height of the image. In addition, the graph for spherical aberration is a graph for light in the wavelength band of about 930 nm and about 940 nm, and the graphs for astigmatic aberration and distortion aberration are graphs for light in the wavelength band of about 940 nm. In the aberration diagram of FIG. 6, it can be interpreted that the closer each curve at room temperature is to the Y-axis, the better the aberration correction function. That is, the optical system (100) according to the embodiment can have improved resolution and good optical performance in the center and periphery of the field of view (FOV).

[0156] FIGS. 7A to 7C are graphs showing ray aberration characteristics at room temperature of the optical system according to the first embodiment. In the ray aberration graphs of FIGS. 7A to 7C, the tangential field curvature and the sagittal field curvature of the optical system are analysis graphs showing lateral aberration in two different directions at relative field heights of 0.0 and 1.0 on the optical axis, and it can be confirmed that the optical system can obtain characteristics in which the lateral aberration is well corrected for light in the wavelength bands of about 930 nm, about 940 nm, and about 950 nm. That is, the camera module according to the embodiment can have improved resolution and good optical performance not only at the center of the field of view (FOV) but also at the periphery.

[0157]

[0158] An optical system according to a second embodiment of the invention will be described. In describing the second embodiment, the same configuration as the first embodiment will be referred to the configuration and description of the first embodiment. Referring to FIGS. 8 to 10, the optical system (100) may include first lenses (111) to sixth lenses (116) aligned from the object side toward the sensor side along the optical axis (OA). The aperture (ST) may be arranged around the sensor-side surface of the third lens (113) or the object-side surface of the fourth lens (114).

[0159] The first lens group includes first to third lenses (111, 112, 113) between the aperture (ST) and the object, and may have a negative value. The second lens group includes fourth to sixth lenses (114-116) arranged between the aperture (ST) and the sensing unit (151), and may have a positive value. At least one or all of the first to sixth lenses (111-116) may include a plastic material or a glass material, and may be, for example, a glass material. The power or refractive power of the first to third lenses (111-113) may have a negative value, and the power or refractive power of the fourth to sixth lenses (114-116) may have a positive value.

[0160] On the optical axis (OA), the first surface (S1) on the object side of the first lens (111) may be convex, and the second surface (S2) on the sensor side may be concave. The first surface (S1) and the second surface (S2) on the optical axis (OA) may be spherical. The first lens (111) may have a meniscus shape that is convex toward the object side. When the refractive index of the first lens (111) is Nd1, the condition of 1.65 < Nd1 or 1.7 < Nd1 < 2 may be satisfied. The refractive index (Nd1) of the first lens (111) may be greater than the refractive index of the second lens (112). If the refractive index (Nd1) of the first lens (111) is lower than the above condition, the lens surface must be formed sharply concave or convex in order to increase the refractive power of the first lens (111). In this case, lens manufacturing is not easy, the lens defect rate increases, and it may cause a decrease in yield.

[0161]

[0162] The second lens (112) may be a spherical lens made of glass. On the optical axis (OA), 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. That is, the second lens (112) may have a meniscus shape that is convex toward the object. The third lens (113) may be an aspherical lens made of glass. On the optical axis (OA), the object-side fifth surface (S5) of the third lens (113) may be convex, and the sensor-side sixth surface (S6) may be concave. On the optical axis (OA), the third lens (113) may have a meniscus shape that is convex toward the object. At least one or both of the fifth surface (S5) and the sixth surface (S6) are aspherical, and as shown in FIG. 10, the third lens is L3 and has a radius of curvature (Y) of the fifth and sixth surfaces (S5, S6), a conic constant, and an aspherical coefficient of the fourth to twentieth order. When the refractive indices of the second and third lenses (112, 113) are Nd2 and Nd3, the condition of Nd2 < Nd3 can be satisfied. When the Abbe number of the second and third lenses (113) is Vd2 and Vd3, the condition of Vd3 < Vd2 can be satisfied.

[0163] The effective diameter of the third lens (113) may be smaller than the effective diameters of the second and fourth lenses (112, 114). The effective diameter of the third lens (113) may be the smallest among the effective diameters of the first to sixth lenses (111-116). The effective diameters of the lenses may gradually decrease from the object toward the aperture (ST). The effective diameters of the lenses may gradually increase from the aperture (ST) toward the last lens. That is, the effective diameter from the first lens (111) to the third lens (113) may gradually decrease. The effective diameter from the third lens (113) to the fifth lens (115) may gradually increase. The effective diameter of each lens is the average of the effective diameters of the object-side surface and the sensor-side surface of each lens.

[0164]

[0165] The fourth lens (114) may be an aspherical lens made of glass. On the optical axis (OA), the object-side seventh surface (S7) of the fourth lens (114) may be concave, and the sensor-side eighth surface (S8) may have a convex shape. The fourth lens (114) may have a meniscus shape convex toward the sensor. At least one or both of the seventh surface (S7) and the eighth surface (S8) are aspherical, and as shown in FIG. 10, the fourth lens is L4, and has a radius of curvature (Y) of the fifth and sixth surfaces (S5, S6), a conic constant, and an aspherical coefficient of the fourth to twentieth orders.

[0166] The fifth lens (115) may be a spherical lens. On the optical axis (OA), the ninth surface (S9) of the fifth lens (115) on the object side may be convex, and the tenth surface (S10) on the sensor side may have a convex shape. The fifth lens (115) may have a convex shape on both sides. Alternatively, the fifth lens (115) may have a meniscus shape that is convex toward the sensor. Alternatively, the fifth lens (115) may have a meniscus shape that is convex toward the object. Alternatively, the fifth lens (115) may have a concave shape on both sides. At least one or both of the ninth surface (S9) and the tenth surface (S10) may be spherical.

[0167] On the optical axis, the absolute value of the radius of curvature of the ninth surface (S9) of the fifth lens (115) may be greater than the absolute value of the radius of curvature of the tenth surface (S10), and may be the largest among the absolute values ​​of the radii of curvature of the lens surfaces. Accordingly, the difference between the absolute value of the radius of curvature of the ninth surface (S9) of the fifth lens (115) and the absolute value of the radius of curvature of the eighth surface (S8) of the fourth lens (114) may be the largest among the differences in the absolute values ​​of the radii of curvature between the lens surfaces of adjacent lenses. Accordingly, the center spacing (CG4) between the fourth and fifth lenses (114, 115) may be smaller than the center spacings (CG1, CG2, CG3) between the first to fourth lenses (111-114).

[0168] The sixth lens (116) may be a spherical lens. On the optical axis (OA), the object-side eleventh surface (S11) of the sixth lens (116) may have a convex shape, and the sensor-side twelfth surface (S12) may have a convex shape. The sixth lens (116) may have a convex shape on both sides. Alternatively, the sixth lens (116) may have a convex meniscus shape toward the sensor. Alternatively, the sixth lens (116) may have a convex meniscus shape toward the object. At least one or both of the ninth surface (S9) and the tenth surface (S10) are spherical. The eleventh and twelfth surfaces (S11, S12) of the first to sixth lenses (111-116) may be provided without a critical point from the optical axis to the end of the effective area, or may have at least one critical point.

[0169] The effective diameter (CA6) of the sixth lens (116) and the effective diameter (CA5) of the fifth lens (115) may have the following conditions.

[0170] Condition: 0.8 < CA5 / CA6 < 1.2

[0171] The difference between the effective diameter (CA6) of the sixth lens (116) and the effective diameter (CA5) of the fifth lens (115) satisfies the following conditions, thereby reducing light loss. The effective diameter of the first lens (116) may be the largest among the lenses. The lens surface with the largest effective diameter among the object-side surfaces of the lenses may be the first surface (S1), and the lens surface with the largest effective diameter among the sensor-side surfaces of the lenses may be the tenth surface (S10). The lens surface with the smallest effective diameter among the object-side surfaces of the lenses may be the fifth surface (S5), and the lens surface with the smallest effective diameter among the sensor-side surfaces of the lenses may be the sixth surface (S6). The effective diameter of the first lens (111) is larger than the effective diameter of the sixth lens (116) closest to the sensing unit (151), and the focal length of the sixth lens (116) is larger than the focal length of the optical system (100), so that an optical system (100) having a small F number and a bright image can be provided.

[0172]

[0173] The radius of curvature of the tenth surface (S10) of the fifth lens (115) is L5R2, and the radius of curvature of the eleventh surface (S11) of the sixth lens (116) is L6R1, and may have the following conditions.

[0174] Condition: 0.7 < |L5R2| / L6R1 < 1.3

[0175] The radius of curvature of the ninth surface (S9) of the fifth lens (115) is L5R1, and the radius of curvature of the twelfth surface (S12) of the sixth lens (116) is L6R2, and may have the following conditions.

[0176] Condition: 5 < L5R1 / |L6R2|

[0177] The central thicknesses of the fifth lens (115) and the sixth lens (116) are CT5 and CT6, and may have the following conditions.

[0178] Condition: 0.8 < CT5 / CT6 < 1.2

[0179] The edge thicknesses of the fifth lens (115) and the sixth lens (116) are ET5 and ET6, and may have the following conditions.

[0180] Condition: 0.7 < ET5 / ET6 < 1.3

[0181] The refractive indices of the fifth lens (115) and the sixth lens (116) are Nd5 and Nd6, and may have the following conditions.

[0182] Condition: 0.8 < Nd5 / Nd6 < 1.2

[0183] The above 5th and 6th lenses (115, 116) can reduce light loss by satisfying the above conditions.

[0184] Since the first and third lenses (111, 113) have negative power, an optical system with a large angle of view can be provided. The fourth lens (114) to the sixth lens (116) can have positive power, so that the F number can be configured to be 1 or less or less than 1. By controlling the effective diameters of each of the lenses (111-116), the optical system (100) can control the incident light to compensate for the deterioration of the optical characteristics due to resolution and temperature change, improve the chromatic aberration control characteristics, and improve the vignetting characteristics of the optical system (100).

[0185] Since the radius of curvature of the object-side first surface (S1) of the first lens (111) is larger than the radius of curvature of the second surface (S2), distortion of reflected light can be reduced and the depth of field can be further increased, thereby improving image quality under low-light conditions.

[0186]

[0187] The optical system (100) or sensor system may include a sensing unit (151). Here, the effective length of the sensing unit (151) is the maximum length in the diagonal direction orthogonal to the optical axis (OA), and here, a lens surface having an effective diameter smaller than the effective length of the sensing unit (151) may be at least one or both of the object-side surface and the sensor-side surface of the third lens (113). The optical system (100) may include an optical filter (153), and the optical filter (153) may be arranged between the sensing unit (151) and the last lens (116). The optical filter (153) may transmit light, for example, a laser wavelength, reflected from a subject after being emitted from a transmission optical system, and block other wavelengths. The transmitted laser wavelength may be in the range of 890 nm to 960 nm or 940 nm ± 10 nm. As another example, the laser wavelength may be in the range of 1550 nm ± 10 nm. The optical filter (153) may be a bandpass filter. The aperture (ST) may control the amount of light incident on the optical system (100). The aperture (ST) will be described in the first embodiment.

[0188] The refractive power of the first lens group having the first to third lenses (111-113) may have a negative (-) value. The refractive power of the second lens group having the fourth to sixth lenses (114-116) may have a positive (+) value. The composite refractive power of the first to third lenses (111-113) may have a negative (-) value, and the composite refractive power of the fourth to sixth lenses (114-116) may have a positive (+) value.

[0189]

[0190] The Sag values ​​of the fifth and sixth lenses of FIG. 8, with reference to FIG. 2, the Sag value of the sensor-side tenth surface (S10) of the fifth lens (115) is Sag52, and the absolute value of Max_Sag52 may be greater than the center spacing (CG5) between the fifth and sixth lenses (115, 116). The Sag value of the object-side eleventh surface (S11) of the sixth lens (116) is Sag61, and the absolute value of Max_Sag61 may be smaller than the absolute value of Max_Sag52. The difference between the absolute value of Max_Sag52 and the Max_Sag61 value may be less than 1 mm. Since the edge portion of the sensor-side surface (S10) of the fifth lens (115) has a large Sag value, the fifth lens (115) can refract the light refracted through the fourth lens (114) to the entire area of ​​the sixth lens (116). Here, the maximum Sag value is the height from the straight line perpendicular to the center of each lens surface to the edge, and if each lens surface is located on the object side relative to the straight line, it may have a negative value, and if it is located on the sensor side, it may have a positive value. The Max_Sag52 value of the sensor-side surface (S10) of the fifth lens (115) is a negative value, and the Max_Sag61 value of the object-side surface (S11) of the sixth lens (116) is a positive value.

[0191] A normal line (K2, see FIG. 2), which is a straight line perpendicular to a tangent line (K1, see FIG. 2) passing through an arbitrary point of the sensor-side tenth surface (S10) of the fifth lens (115), may be inclined at a first angle (R1, see FIG. 2) with respect to the optical axis (OA), and when the first angle (R1) is the maximum, it may be greater than 5 degrees and less than 65 degrees, for example, in the range of 10 degrees to 50 degrees or in the range of 30 degrees to 40 degrees. Accordingly, the shape of the fifth lens (115) and the length ratio of the TTL and the sensing unit (151) can be adjusted.

[0192] The normal line, which is a straight line perpendicular to the tangent line passing through any point of the object-side eleventh surface (S11) of the sixth lens (116), can be inclined at a second angle with respect to the optical axis (OA), and when the second angle is the maximum, it can be more than 5 degrees and less than 65 degrees, for example, it can be in the range of 10 degrees to 50 degrees or 30 degrees to 40 degrees. Accordingly, the shape of the fifth lens (115) and the length ratio of the TTL and the sensing unit (151) can be adjusted.

[0193]

[0194] The central thickness of each lens and the optical axis spacing between adjacent lenses can satisfy at least one of the following conditions.

[0195] Condition 1: CT1 < CT6 Condition 2: CT2 < CT5

[0196] Condition 3: CT3 < CT4 Condition 4: (CT1+CT2+CT3) < (CT5+CT6)

[0197] Condition 5: CT1 < ET1 < CT4 Condition 6: CT2 < ET2 < CT4

[0198] Condition 7: CG2 < CT1 < CG1 Condition 7: CG4 < CG5 < CG3

[0199] Condition 8: CG2 < CG3 < CT4

[0200] Here, the difference between the maximum center spacing and the minimum center spacing may be 1 mm or more, for example, in the range of 1 mm to 3 mm. Furthermore, by providing the maximum center spacing between the lenses to be smaller than the maximum center thickness of each lens, a receiving optical system with a small center spacing between the lenses can be provided. Furthermore, since the maximum center spacing between the lenses is provided to be larger than the minimum center thickness of each lens, the optical path can be controlled. By controlling the center thickness of these lenses, the sensor system can be slimmed down and thermally compensated for temperature changes from low to high temperatures.

[0201]

[0202] The effective diameter of each lens can satisfy the following conditions.

[0203] Condition 1: CA12 < CA11 < CA12*2 Condition 2: CA3 < CA2 < CA1

[0204] Condition 3: CA3 < CA4 < CA5 Condition 4: CA6 ≤ CA5 < CA1

[0205] Condition 5: 0.8 < CA6 / CA5 < 1.2 Condition 6: 0.8 < CA52 / CA61 < 1.2

[0206] Condition 7: 0.8 < CA51 / CA52 < 1.2 Condition 8: 0.8 < CA61 / CA62 < 1.2

[0207] The effective diameter of each of the first, second, and fourth to sixth lenses (111, 112, 114-116) may be greater than the diagonal length of the effective area of ​​the sensing unit (151). The third lens (113) may be smaller than the diagonal length of the effective area of ​​the sensing unit (151). These lenses can guide incident light to the entire area of ​​the sensing unit (151).

[0208]

[0209] Fig. 9 is an example of lens data of the optical system of the embodiment of Fig. 8. As shown in Fig. 9, the radius of curvature on the optical axis (OA) of the first to sixth lenses (111-116), the center thickness (CT) of the lenses, the center gap (CG) between the lenses, the refractive index at the d-line, the Abbe number, the focal length of each lens, and the size of the effective diameter of each lens surface can be set.

[0210] As shown in FIG. 10, among the lenses of the embodiment of FIG. 8, the lens surfaces (S5, S6, S7, S8) of the third and fourth lenses (113, 114) may include an aspherical surface having a radius of curvature (Y), a conic constant, and a 20th aspherical coefficient. For example, an aspherical surface having a 20th aspherical coefficient (a non-zero value) as described above can significantly change the aspherical shape of the periphery, thereby effectively compensating for the optical performance of the periphery of the field of view (FOV).

[0211]

[0212] The refractive power (F1-F6) and overall focal length (F) of each lens can satisfy the following conditions.

[0213] Condition 1: │F1│ < │F2│ Condition 2: F4 < │F3│ < │F2│

[0214] Condition 3: 0.5 < F4 / F5 < 1.5 Condition 4: 0.8 < F5 / F6 < 1.2

[0215] Condition 5: F < F5 Condition 6: F < │F1│

[0216] Condition 7: F < BFL

[0217] Here, F is the effective focal length of the optical system, and BFL is the optical axis distance from the last lens, i.e., the sixth lens (116), to the surface of the image sensor, which is the sensor unit (151). Accordingly, the optical system can have improved MTF characteristics, aberration control characteristics, resolution characteristics, etc. in the set field of view range, and can have good optical performance in the periphery of the field of view.

[0218]

[0219] TTL is the optical axis distance from the object side of the first lens (111) to the surface of the sensor unit (151), and FOV is the angle of view of the optical system. TTL and FOV can satisfy the following conditions.

[0220] Condition 1: CA12*2 < TTL < CA12*3

[0221] Condition 2: |F2| < TTL

[0222] Condition 3: 0.1 < TTL / FOV < 0.5

[0223]

[0224] Fig. 11 is a graph showing the diffraction MTF in the optical system of Fig. 8, and is a graph showing the modulation of the luminance according to the spatial frequency. That is, Fig. 11 shows the diffraction MTF at room temperature, and is a graph measuring the luminance ratio according to the defocusing position.

[0225] Fig. 12 is a graph showing the aberration characteristics in the optical system of Fig. 8. In the aberration graph of Fig. 12, astigmatic field curves and distortion are measured from left to right. In Fig. 12, the X-axis may represent the focal length (mm) and the degree of distortion (%), and the Y-axis may represent the height of the image. In addition, the graph for spherical aberration is a graph for light in the wavelength band of about 930 nm and about 940 nm, and the graphs for astigmatic aberration and distortion aberration are graphs for light in the wavelength band of about 940 nm. In the aberration diagram of Fig. 12, it can be interpreted that the closer each curve at room temperature is to the Y-axis, the better the aberration correction function. That is, the optical system (100) according to the embodiment can have improved resolution and good optical performance in the center and periphery of the field of view (FOV).

[0226] FIGS. 13A to 13C are graphs showing ray aberration characteristics at room temperature of the optical system according to the first embodiment. In the ray aberration graphs of FIGS. 13A to 13C, the tangential field curvature and the sagittal field curvature of the optical system are analysis graphs showing lateral aberration in two different directions at relative field heights of 0.0 and 1.0 on the optical axis, and it can be confirmed that the optical system can obtain characteristics in which the lateral aberration is well corrected for light in the wavelength bands of about 930 nm, about 940 nm, and about 950 nm. That is, the camera module according to the embodiment can have improved resolution and good optical performance not only at the center of the field of view (FOV) but also at the periphery.

[0227]

[0228] The optical system (100) according to the first and second embodiments generates chromatic aberration, and can correct the chromatic aberration by mixing spherical lenses and aspherical lenses. When the lens repeatedly contracts and expands as the temperature changes from low to high, since the lens characteristics of the glass material lenses change the same amount due to the temperature change, it is effective to correct the chromatic aberration between lenses of the same material even when the temperature changes. In addition, since the optical system (100) uses at least one aspherical lens as a glass lens, temperature compensation for the aspherical lens is possible, and a decrease in the reliability of the optical characteristics can be prevented. The optical system of the above-described embodiment can effectively control aberration characteristics such as chromatic aberration and distortion aberration, and can have good optical performance at the center and periphery of the field of view (FOV).

[0229] The receiving optical system according to the first and second embodiments of the invention can prevent the degradation of optical performance from low to high temperatures by considering the characteristics of the vehicle optical system. For example, after designing the lens at room temperature, the value of the dn / dt, which is a temperature-dependent refractive index change coefficient, is assembled by considering the power combination of each lens, and the value of the temperature coefficient according to the refractive index of the lens and the defocus for the thickness variable according to low, room, and high temperatures can be set to 5㎛ or less. For this purpose, the first to sixth lenses are made of a spherical glass material.

[0230]

[0231] The optical system of the first and second embodiments may have a Chief ray angle (CRA) of less than 10 degrees. Table 1 shows the Chief ray angle (CRA) values ​​according to the height from the center field (0.0 Field) to the end field (1.0 Field) of the image sensor in the first and second embodiments.

[0232] CRAField (Sensor height) Example 1 Example 2 00.000.000.10.390.240.20.570.530.30.190.920.40.091.420.50.662.050.61.722.780.72.783.550.83.824.310.94.804.9915.585.54

[0233] The optical system (100) according to the embodiment disclosed above can satisfy at least one or two or more of the mathematical equations described below. Accordingly, the optical system (100) according to the embodiment can have improved optical characteristics. For example, when the optical system (100) satisfies at least one mathematical equation, the optical system (100) can effectively control aberration characteristics such as chromatic aberration and distortion aberration, and can have good optical performance even in the center and periphery of the field of view (FOV). In addition, the optical system (100) can have improved resolution. In addition, the thickness of the lens on the optical axis (OA) described in the mathematical equations and the spacing between adjacent lenses on the optical axis (OA) may refer to the embodiment disclosed above.

[0234] [Mathematical Formula 1] 0.5 < CT1 / CT2 < 1.5

[0235] In mathematical expression 1, by setting the central thickness (CT1) of the first lens (101, 111) and the central thickness (CT2) of the second lens (102, 112), the rigidity of the first lens (101, 111) can be prevented from decreasing, and factors affecting aberration can be controlled. Preferably, mathematical expression 1 can satisfy 0.8 < CT1 / CT2 < 1.2.

[0236] [Equation 2] 3 < CA11 / CT1

[0237] In mathematical expression 2, the center thickness (CT1) of the first lens (101, 111) and the effective diameter (CA11) of the object-side surface (S1) of the first lens (101, 111) can be set. When the optical system satisfies mathematical expression 2, the strength and optical properties of the glass lens can be prevented from being deteriorated. If it is lower than the range of mathematical expression 1, the lens may be damaged or the incidence efficiency may be reduced, and if it is larger than the above range, the TTL may increase and the weight of the optical system may become heavier. Preferably, mathematical expression 2 can satisfy 7 < CA11 / CT1 < 15.

[0238] [Mathematical Formula 3] 0.5 < CT6 / CT5 < 1.5

[0239] In mathematical expression 3, the central thickness (CT5) of the fifth lens (105, 115) and the central thickness (CT6) of the sixth lens (106, 116) can be set, thereby optimizing thermal compensation according to temperature changes from low to high temperatures and preventing degradation of optical performance. Preferably, mathematical expression 3 can satisfy 0.8 < CT6 / CT5 < 1.2.

[0240] [Equation 4] 0.5 < CT6 / (CT1+CT2) < 1.5

[0241] In mathematical expression 4, the central thickness (CT6) of the sixth lens is set to be 0.5 times greater than the sum of the central thicknesses (CT1, CT2) of the first and second lenses, so that the light refracted from the fifth lens can be guided to the sensing unit (151). Preferably, mathematical expression 4 can satisfy 0.8 < CT6 / (CT1+CT2) < 1.2. Accordingly, the central thickness (CT6) of the sixth lens (106, 116) closest to the sensing unit (151) can be set to be thicker than the central thickness (CT1) of the first lens (101, 111), and the effective diameter of the sixth lens can be set to be smaller than the effective diameter of the first lens.

[0242] [Equation 5] 0.1 < CG3 / CT6 < 1

[0243] In mathematical expression 5, the center spacing (CG3) between the third and fourth lenses and the center thickness (CT6) of the sixth lens are set, so that the change in light incident on the sensor unit (151) due to the thickness of the sixth lens (106, 116) can be reduced. Preferably, mathematical expression 5: 0.2 < CG3 / CT6 < 0.5 can be satisfied.

[0244] [Equation 6] 0 < CG5 / CG1 < 0.8

[0245] In mathematical expression 6, the center spacing between the first and second lenses (CG1) and the center spacing between the fifth and sixth lenses (CG5) can be set to set the center spacing between the spherical lenses. Preferably, 0.2 < CG5 / CG6 < 0.6 can be satisfied.

[0246] [Mathematical Formula 7] 1 < (CA11*L1R1) / (CA31*L3R1) < 5

[0247] Mathematical expression 7 can set the effective radii of curvature of the object-side lens and the sensor-side lens of the first lens group. That is, by setting the effective diameter (CA11) and the radius of curvature (L1R1) of the object-side surface of the first lens, and the effective diameter (CA31) and the radius of curvature (L3R1) of the object-side surface of the third lens, the amount of incident light can be increased. Preferably, 1.5 < (CA11*L1R1) / (CA31*L3R1) < 2.5 can be satisfied.

[0248] [Equation 8] 2 < (CA11*CT1) / (CA31*CT3) < 6

[0249] Mathematical expression 7 can set the effective diameter and center thickness of the object-side lens and the sensor-side lens of the first lens group. That is, by setting the effective diameter (CA11) and center thickness (CT1) of the object-side surface of the first lens, and the effective diameter (CA31) and center thickness (CT3) of the object-side surface of the third lens, the path of the incident light can be controlled. Preferably, 3 < (CA11*CT1) / (CA31*CT3) < 5 can be satisfied.

[0250] [Equation 9] 5 < TTL / CT_AVER < 25

[0251] In mathematical expression 9, CT_AVER is the average of the central thicknesses of the first to fifth lenses, and can set the total optical axis length (TTL) and the central thicknesses of the lenses. Accordingly, the central thicknesses of 7 or fewer glass lenses can be set according to the optical axis length.

[0252]

[0253] [Equation 10] 1.65 < Nd1

[0254] Nd1 is the refractive index at the d-line of the first lens (101, 111). In Equation 10, by setting the refractive index of the first lens (101, 111) high, the factor affecting the reduction of the third-order aberration (Seidel aberration) of the optical system can be adjusted, and the aberration that may occur as the TTL becomes somewhat longer can be reduced. Equation 10 can preferably satisfy 1.70 < Nd1 < 2. If it is designed to be lower than the lower limit of Equation 10, the performance of reducing aberration can be obtained, and the refractive power of the first lens may be weakened so that light cannot be collected efficiently, which may lower the performance of the optical system. If it is designed to be higher than the upper limit of Equation 10, there is a disadvantage in that it is difficult to obtain materials. In addition, when the refractive index of the first lens (101, 111) is designed to be lower than the lower limit of mathematical expression 10, the radius of curvature of the first and second lenses can be increased to increase the refractive power of the first and second lenses.

[0255] [Equation 10-1] 1.73 < Aver(Nd1:Nd6) < 1.83

[0256] Aver(Nd1:Nd6) is the average of the refractive index values ​​at the d-line of the first to sixth lenses. When mathematical expression 10-1 is satisfied, the optical system (100) can set the resolution and suppress the influence on TTL. In addition, in terms of the refractive indices of the lenses, the average of the refractive indices of the aspherical lenses may be greater than the average of the refractive indices of the first and second lenses, which are spherical lenses. The spherical lens is a lens made of a glass material that is not injection-molded, and the aspherical lens is a lens made of an injection-molded glass material.

[0257] [Equation 11] 3.4 < (Nd1+Nd3) < 3.8

[0258] Nd1 and Nd3 are the refractive indices of the first and third lenses at the d-line. In Equation 11, by setting the sum of the refractive indices of the first lens and the third lens, the reduction in color dispersion caused by lenses made of glass can be prevented.

[0259] [Equation 12] 1.7 < Aver(Nd3:Nd6) < 2.0

[0260] In mathematical expression 12, the average refractive index of the third to sixth lenses can be set. In mathematical expression 12, by setting a spherical lens made of glass and an aspherical lens made of glass, the reduction in color dispersion caused by the lenses can be prevented.

[0261] [Equation 13] 0.5 < |Ln-1R2 / LnR1| < 1.5

[0262] In mathematical expression 13, Ln-1R2 is the radius of curvature of the sensor-side surface of the (n-1)th lens, and LnR1 is the radius of curvature of the object-side surface of the (n)th lens. When mathematical expression 13 is satisfied, the optical path of the last two lenses adjacent to the sensing unit (151) can be adjusted, and the deterioration of optical performance in the center and periphery of the sensing unit (151) can be prevented. Preferably, 0.8 < |Ln-1R2 / LnR1| < 1.2 can be satisfied.

[0263] [Mathematical Formula 14] 1 < |Ln-1R1 / LnR2|

[0264] In mathematical expression 14, Ln-1R1 is the radius of curvature of the object-side surface of the (n-1)th lens, and LnR2 is the radius of curvature of the sensor-side surface of the (n)th lens. When mathematical expression 14 is satisfied, the optical path of the last two lenses adjacent to the sensing unit (151) can be adjusted, and the deterioration of optical performance in the center and periphery of the sensing unit (151) can be prevented. Preferably, the first embodiment satisfies 1 < |Ln-1R1 / LnR2| < 1.6, and the second embodiment can satisfy 5 < |Ln-1R1 / LnR2| < 20 or 10 < |Ln-1R1 / LnR2| < 20.

[0265]

[0266] [Equation 15] 2 < |Ln-1R2 / CTn-1| < 5

[0267] In mathematical expression 15, CTn-1 is the central thickness of the (n-1)th lens. When mathematical expression 15 is satisfied, the optical path of the last two lenses adjacent to the sensing unit (151) can be adjusted, and the degradation of optical performance in the central and peripheral parts of the sensing unit (151) can be prevented. Preferably, 2.3 < |Ln-1R2 / CTn-1| < 4 can be satisfied.

[0268] [Equation 16] 2 < |LnR1 / CTn| < 5

[0269] In mathematical expression 16, CTn is the central thickness of the nth lens. When mathematical expression 16 is satisfied, the optical path of the last lens adjacent to the sensing unit (151) can be adjusted, and the deterioration of optical performance in the central and peripheral regions of the sensing unit (151) can be prevented. Preferably, 2.2 < |LnR1 / CTn| < 4 can be satisfied.

[0270] [Mathematical Formula 17] 5mm < AVER(|F1| : Fn|) < 30mm

[0271] AVER(|F1| : Fn|) is the average (absolute value) of the focal lengths from the first lens to the nth lens, the sixth lens. If Equation 16 is satisfied, the resolution of the optical system can be controlled.

[0272]

[0273] [Mathematical Formula 18] 1 < CA11 / CA21 < 5

[0274] CA11 refers to the effective diameter of the first surface (S1) of the first lens (101, 111), and CA21 refers to the effective diameter of the third surface (S3) of the second lens (102, 112). When mathematical expression 18 is satisfied, the optical system (100) can control the incident light and set the factors affecting aberration, and preferably, 1.3 < CA11 / CA21 < 3 can be satisfied.

[0275] [Mathematical Formula 19] 0 < CA32 / CA41 < 2

[0276] CA32 refers to the effective diameter of the sixth surface (S6) of the third lens, and CA41 refers to the effective diameter of the seventh surface (S7) of the fourth lens. When mathematical expression 19 is satisfied, the optical system (100) can control the incident light path and set the sensor-side surface of the third lens to a concave shape. Preferably, mathematical expression 19 can satisfy 0.5 < CA32 / CA41 < 1.

[0277] [Equation 20] 0.8 < CA52 / CA61 < 1.2

[0278] CA52 refers to the effective diameter of the tenth surface (S10) of the fifth lens, and CA61 refers to the effective diameter of the eleventh surface (S11) of the sixth lens. When mathematical expression 20 is satisfied, the optical system (100) can set a light path incident on the sensing unit (151) through the fifth lens and the sixth lens. Mathematical expression 20 can preferably satisfy 0.9 < CA42 / CA51 < 1.1.

[0279] [Mathematical Formula 21] 1 < CA11 / CA62 < 5

[0280] CA11 is the effective diameter of the first surface (S1) of the first lens, and CA62 is the effective diameter of the twelfth surface (S12) of the sixth lens. When the optical system (100) satisfies mathematical expression 21, the incident amount of the first lens, the spherical lens, can be increased, and the path of light toward the sensing unit can be set through the last lens, the spherical lens. Mathematical expression 21 can preferably satisfy 1.5 < CA11 / CA62 < 3.

[0281]

[0282] [Equation 22] 13 < TTL / Nd1

[0283] In mathematical expression 22, the total optical axis length (TTL) and the refractive index of the first lens can be set. When mathematical expression 22 is satisfied, the total optical axis length can be set to be 50 times greater than the refractive index of the first lens. Preferably, mathematical expression 22: 13 < TTL / Nd1 < 20 can be satisfied.

[0284] [Equation 23] 10 < CA11 / Nd1 < 30

[0285] In mathematical expression 23, the effective diameter of the object-side first surface (S1) of the first lens and the refractive index of the first lens can be set. When mathematical expression 23 is satisfied, the effective diameter of the first surface can be set to be 10 times greater than the refractive index of the first lens. Preferably, mathematical expression 22: 10 < CA11 / Nd1 < 20 can be satisfied.

[0286] [Equation 24] 0.2 < CAn-1 / CA3 < 1

[0287] CAn-1 represents the effective diameter of the n-1th lens, i.e., the fifth lens. If mathematical expression 24 is satisfied, the light path passing through the second lens group can be controlled. Preferably, 0.3 < CAn-1 / CA3 < 0.8 can be satisfied.

[0288]

[0289] [Equation 25] 0.5 < CT6 / BFL < 2

[0290] In mathematical expression 25, when the central thickness (CT6) of the sixth lens and the optical axis distance (BFL) between the fifth lens and the sensing unit (151) are satisfied, the incident light can be transmitted to the entire area of ​​the sensing unit (151) by the sixth lens. Preferably, 0.5 < CT6 / BFL < 1 can be satisfied.

[0291] [Equation 26] 3 < TTL / CG_Max

[0292] In Equation 26, the total optical axis length (TTL) can be set to be three times greater than the maximum center spacing (CG_Max) among the center spacings between lenses. Accordingly, the maximum center spacing can be set within the total optical axis length. Preferably, Equation 26: 5 < TTL / CG_Max < 15 can be satisfied.

[0293] [Equation 27] 3 < TTL / CT_Max

[0294] In Equation 27, the total optical axis length (TTL) can be set to exceed three times the maximum interval (CT_Max) among the center thicknesses of the lenses. Accordingly, the maximum center thickness of the lenses can be set within the total optical axis length. Preferably, Equation 27: 5 < TTL / Max_CT < 10 can be satisfied.

[0295]

[0296] [Equation 28] 10 < |L6R2| / CT6

[0297] L6R2 is the radius of curvature of the sensor-side surface of the sixth lens. When mathematical expression 28 is satisfied, the refractive power of the sixth lens (106, 116) can be controlled and optical performance can be improved. Preferably, 13 < |L6R2| / CT6 can be satisfied.

[0298] [Equation 29] 1 < |L6R2| / L6R1 < 40

[0299] If mathematical expression 29 is satisfied, the refractive power of the sixth lens (106, 116) can be controlled and the optical performance can be improved.

[0300] [Mathematical Formula 30] 1 < L1R1 / L1R2

[0301] 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. When mathematical expression 30 is satisfied, the refractive power of the first lens (101, 111) can be controlled and the optical performance can be improved. Preferably, 2 < L1R1 / L1R2 < 5 can be satisfied.

[0302] [Equation 31] 0.5 < L1R2 / L2R1 < 1.5

[0303] L1R2 is the radius of curvature of the sensor-side surface of the first lens, and L2R1 is the radius of curvature of the object-side surface of the second lens. When mathematical expression 31 is satisfied, the refractive power of the first and second lenses can be controlled to improve optical performance, and the effective diameter of the object-side lens of the second lens (102, 112) can be adjusted. Preferably, mathematical expression 31 can satisfy 0.8 < L1R2 / L2R1 < 1.

[0304] [Equation 32] 0 < CT_Max / CG_Max < 2

[0305] In Equation 32, the maximum center thickness (CT_Max) among the lenses and the maximum center spacing (CG_Max) between adjacent lenses can be set. When Equation 32 is satisfied, the optical system can have good optical performance at the focal length of the set angle of view and can reduce the TTL. Preferably, Equation 32: 1 < CT_Max / CG_Max < 1.5 can be satisfied.

[0306]

[0307] [Equation 33] 1 < ΣCT / ΣCG < 3

[0308] ΣCT is the sum of the central thicknesses of the lenses, and ΣCG is the sum of the spacings between adjacent lenses. When Equation 33 is satisfied, the optical system can have good optical performance at the focal length at the set angle of view, and can reduce the TTL. Here, the condition: ΣCG < ΣCT can be satisfied.

[0309] [Equation 34] 5 < ΣNd < 15

[0310] ΣNd represents the sum of the refractive indices at the d-line of each of the plurality of lenses. When mathematical expression 34 is satisfied, TTL can be controlled in an optical system (100) in which aspherical lenses and spherical lenses are mixed, and improved resolution can be achieved. In addition, when the number of spherical lenses is greater than the number of aspherical lenses, the sum of TTL and refractive indices can be set. Mathematical expression 34 can preferably satisfy 9 < ΣNd < 12.

[0311] [Equation 35] 10 < ΣVd / ΣNd < 50

[0312] ΣVd means the sum of the Abbe numbers of each of the plurality of lenses. When mathematical expression 35 is satisfied, the optical system (100) can have improved aberration characteristics and resolution. By setting the sum of the Abbe numbers and the sum of the refractive indices of the lenses in mathematical expression 35, the optical characteristics can be controlled, and preferably, 20 < ΣVd / ΣNd < 31 can be satisfied.

[0313] [Equation 36] 50 < ΣCT*n < 150

[0314] ΣCT is the sum of the central thicknesses of multiple lenses, and n is the number of lenses in the optical system. If mathematical expression 36 is satisfied, TTL can be controlled. Preferably, 80 < ΣCT*n < 120 can be satisfied.

[0315]

[0316] [Equation 37] 2 < CA11 / CA_Min < 5

[0317] CA_Min represents the minimum effective diameter between the object-side and sensor-side surfaces of the lenses. When Equation 37 is satisfied, the optical system can control incident light, maintain optical performance, and provide a slimmer module. Equation 38 preferably satisfies 3 < CA11 / CA_Min < 5.

[0318] [Equation 38] 3 < CA_Max / CG_Max < 10

[0319] CA_Max represents the maximum effective diameter among the lens surfaces, and CG_Max represents the maximum center spacing among the lenses. If mathematical expression 38 is satisfied, the maximum center spacing is arranged within the range based on the maximum effective diameter, thereby reducing the TTL. Preferably, 5 < CA_Max / CG_Max < 9 can be satisfied.

[0320] [Equation 39] 1.5mm < |Max_Sag52 | < 3mm

[0321] In mathematical expression 39, Max_Sag52 is the maximum distance from a straight line extending in a direction perpendicular to the center of the sensor-side surface of the fifth lens (105, 115) in the object-side direction to the tenth surface (S10), and may have a negative value. When mathematical expression 39 is satisfied, since the edge of the sensor-side surface of the fifth lens (105, 115) extends in the object-side direction, light traveling to the area between the fourth and sixth lenses can be guided. Preferably, 1.8 < |Max_Sag52 | < 2.8 can be satisfied.

[0322] [Equation 39-1] 1.5mm < |Max_Sag62 | < 3mm

[0323] In mathematical expression 39, Max_Sag61 is the maximum distance from a straight line extending in a direction perpendicular to the center of the object-side surface of the fifth lens (105, 115) to the eleventh surface (S11) in the object-side direction, and may have a positive value. When mathematical expression 39 is satisfied, since the edge of the object-side surface of the fifth lens (105, 115) extends in the sensor-side direction, light traveling to the area between the fifth and sixth lenses can be guided. Preferably, 1.8 < |Max_Sag61 | < 2.8 can be satisfied.

[0324]

[0325] [Mathematical Formula 40] 5 degrees < |Max_slope52| < 65 degrees

[0326] In mathematical expression 7, Max_slope52 means the maximum angle (Degree) between the normal perpendicular to the tangent measured on the sensor-side 10th surface (S10) of the fifth lens (105, 115) and the optical axis. Specifically, on the 10th surface (S10), Max_slope52 means a value at which the angle (R1) between the normal (K2, FIG. 2) perpendicular to the tangent (K1) passing through an arbitrary point of the 10th surface (S10) and the optical axis (OA) is maximum. When the optical system (1000) according to the embodiment satisfies mathematical expression 40, the optical system (1000) can control the occurrence of lens flare. Preferably, mathematical expression 40 can satisfy 25 degrees < |Max_slope62| < 40 degrees.

[0327]

[0328] [Mathematical Formula 41] 1 < CA_Max / (2*ImgH) < 5

[0329] In mathematical expression 42, the maximum effective diameter (CA_Max) of the lens surface can be set to the diagonal length (2*ImgH) of the sensing unit (151), and if this is satisfied, the optical system can maintain good optical performance and a slim and compact sensor device can be set.

[0330] [Equation 42] 1 < TD / CA_Max < 4

[0331] TD is the optical axis distance from the center of the object-side surface of the first lens to the center of the sensor-side surface of the last lens. When mathematical expression 42 is satisfied, the total optical axis distance (TD) and maximum effective diameter of the lenses can be set, thereby setting the size for good optical performance. Mathematical expression 42 preferably satisfies 1 < TD / CA_Max < 3.

[0332] [Equation 43] 0 < F / │LnR2│ < 0.5

[0333] F is the effective focal length of the optical system, and LnS2 is the radius of curvature of the sensor-side surface of the nth lens, i.e., the sixth lens. When mathematical expression 43 is satisfied, the effect on optical system reduction, e.g., TTL, can be controlled by setting the effective focal length and the radius of curvature of the sensor-side surface of the last aspherical lens. Mathematical expression 43 can preferably satisfy 0 < F / │L6R2│ < 0.2.

[0334] [Equation 44] 0 < F / L1R1 < 0.5

[0335] In mathematical expression 44, the effective focal length of the optical system and the radius of curvature of the object-side surface of the first lens can be set to control the influence on the incident light and TTL. Mathematical expression 44 can preferably satisfy 0 < F / L1R1 < 0.2.

[0336] [Equation 45] 0 < EPD / │LnR2│ < 0.5

[0337] EPD refers to the size of the entrance pupil diameter of the optical system (100). When the optical system (100) according to the embodiment satisfies mathematical expression 45, the optical system (100) can control incident light. Preferably, the condition of 0 < EPD / L6R2 < 0.1 can be satisfied.

[0338]

[0339] [Equation 46] 0 < EPD / L1R1 < 0.5

[0340] In mathematical expression 46, the size of the entrance pupil of the optical system (100) and the radius of curvature of the object-side surface of the first lens can be set, and when these are satisfied, the optical system (100) can control the incident light. Preferably, the condition of 0 < EPD / L1R1 < 0.2 can be satisfied.

[0341] [Equation 47] 2 < |F1│ / F < 8

[0342] F1 is the focal length of the first lens, and F is the overall focal length. If Equation 47 is satisfied, the power of the first lens can be set negative for an optical system with an angle of view of 110 degrees or more. Preferably, 3 < |F1│ / F < 8 can be satisfied.

[0343]

[0344] [Equation 48] 0 < |F13| / F46 < 2

[0345] F13 is the composite focal length of the first to third lenses, and F46 is the composite focal length of the fourth to sixth lenses. If mathematical expression 48 is satisfied, an optical system having an angle of view of 110 degrees or more can be set. F13 is the focal length of the first lens group, and F46 is the focal length of the second lens group. Preferably, 0.5 < |F13| / F46 < 1 can be satisfied.

[0346] [Equation 49] 0 < |F1 / F6| < 3

[0347] In mathematical expression 49, the focal lengths of the first and sixth lenses can be set, and the refractive powers of the first and sixth lenses can be controlled to improve the resolution. Preferably, 1 < |F1 / F6| < 1.5 can be satisfied.

[0348] [Mathematical Formula 50] 0 < F4 / F5 < 2

[0349] The fourth and fifth lenses are provided as spherical lenses with positive power, which can improve aberrations. Preferably, 0.8 < F4 / F5 < 1.2 or 0.8 < F4 / F5 < 1 can be satisfied.

[0350]

[0351] [Mathematical Formula 51] 20mm < TTL

[0352] TTL refers to the distance from the center of the first surface (S1) of the first lens (101, 111) to the imaging surface of the sensing unit (151) on the optical axis (OA). If mathematical expression 51 is satisfied, it can be applied to a vehicle optical system having TTL. In mathematical expression 51, 25 mm < TTL < 45 mm can be satisfied.

[0353] [Mathematical Formula 52] 2mm < ImgH

[0354] Mathematical expression 52 can set half of the diagonal size of the sensing unit (151) and can provide an optical system having a vehicle sensor size. Mathematical expression 52 can preferably satisfy 2 mm < ImgH < 10 mm or 2.5 mm < ImgH < 6 mm.

[0355] [Mathematical Formula 53] 3mm < BFL < 20mm

[0356] In mathematical expression 53, the BFL (Back focal length) is set to exceed 3 mm, thereby securing the installation space of the optical filter (153), improving the assemblability of components through the gap between the sensing unit (151) and the last lens, and improving the joint reliability. Mathematical expression 53 can preferably satisfy 4 mm < BFL < 10 mm. When the BFL is less than the range of mathematical expression 53, some of the light proceeding to the sensing unit may not be transmitted to the sensing unit, which may cause a decrease in resolution. When the BFL exceeds the range of mathematical expression 53, stray light may be introduced, which may deteriorate the aberration characteristics of the optical system.

[0357] [Mathematical Formula 54] 1mm < F < 15mm

[0358] Mathematical expression 54 can set the overall focal length (F) to suit the vehicle optical system. Mathematical expression 54 can satisfy 2 mm < F < 8 mm.

[0359] [Mathematical Formula 55] 100 degrees < FOV

[0360] In mathematical expression 55, FOV (Field of view) means the angle of view (Degree) of the optical system (100), and a vehicle optical system having an angle of view (F0V) exceeding 100 degrees can be provided. Preferably, mathematical expression 55: 110 degrees ≤ FOV ≤ 250 degrees can be satisfied. Here, the FOV disclosed in the embodiment of the invention is a horizontal angle of view. In mathematical expression 55, the range of the vehicle optical system can be set by the angle of view. When mathematical expression 55 is satisfied, when the temperature changes from room temperature to high temperature, the change rate of the effective focal length and the change rate of the angle of view can be set to 5% or less, for example, 0 to 5%. In addition, even if an aspherical lens and a spherical lens are mixed and used in the optical system (100), the deterioration of the optical characteristics can be prevented through temperature compensation and aberration correction by a lens made of glass.

[0361]

[0362] [Equation 56] 0 < TTL / Ad1 < 1

[0363] Mathematical expression 56 establishes a relationship between the overall optical axis length of the optical system and the Abbe number of the first lens (101, 111), thereby providing an improved vehicle optical system. Mathematical expression 56 preferably satisfies 0.2 < TTL / Ad1 < 0.8.

[0364] [Mathematical Formula 57] 5 < TTL / ImgH < 15

[0365] Mathematical expression 57 can set the total optical axis length (TTL) of the optical system and half of the diagonal length of the sensing unit (151). When the optical system (100) according to the embodiment satisfies Mathematical expression 57, the optical system (100) can have TTL for application to the vehicle sensing unit (151), thereby providing improved image quality. Mathematical expression 57 can preferably satisfy 6 < TTL / ImgH < 12.

[0366] [Equation 58] 0 < BFL / ImgH < 3

[0367] Mathematical expression 58 can set the optical axis distance between the sensing unit (151) and the last lens and the length in the diagonal direction from the optical axis of the sensing unit (151). Mathematical expression 58 can satisfy 1 < BFL / ImgH < 2. When the optical system (100) according to the embodiment satisfies Mathematical expression 58, the optical system (100) can secure a BFL for applying the size of the vehicle sensing unit (151), can set the distance between the last lens and the sensing unit (151), and can have good optical characteristics in the center and periphery of the field of view (FOV).

[0368] [Equation 59] 4 < TTL / BFL < 9

[0369] Mathematical expression 59 can set the total optical axis length (TTL) of the optical system and the optical axis spacing (BFL) between the sensing unit (151) and the last lens. When the optical system (100) according to the embodiment satisfies Mathematical expression 59, the optical system (100) can secure BFL. Mathematical expression 59 can preferably satisfy 5 < TTL / BFL < 8.

[0370] [Equation 60] 0 < F / TTL < 0.5

[0371] Mathematical expression 60 can set the total focal length (F) and the total optical axis length (TTL) of the optical system (100). Accordingly, an optical system for a driver assistance system can be provided. Mathematical expression 60 can satisfy 0 < TTL / F < 0.2. When the optical system (100) according to the embodiment satisfies Mathematical expression 60, the optical system (100) can have an appropriate focal length and a wide angle of view in the set TTL range, and provides an optical system that can form an image while maintaining an appropriate focal length even when the temperature changes from low to high. When it is less than the lower limit of Mathematical expression 60, it is necessary to increase the refractive power of the lenses, making it difficult to correct spherical aberration or distortion aberration, and when it is more than the upper limit of Mathematical expression 60, the effective diameter or TTL of the lenses becomes long, which may cause a problem of the imaging lens system becoming large.

[0372] [Equation 61] 0 < F / BFL < 1

[0373] Mathematical expression 61 can set the total focal length (F) of the optical system (100) and the optical axis distance (BFL) between the sensing unit (151) and the last lens. When the optical system (100) according to the embodiment satisfies Mathematical expression 61, the optical system (100) can have a set angle of view and an appropriate focal length, and an optical system for a vehicle can be provided. In addition, the optical system (100) can minimize the distance between the last lens and the sensing unit (151), and thus can have good optical characteristics in the periphery of the field of view (FOV). Mathematical expression 61 can preferably satisfy 0.4 < F / BFL < 1.

[0374] [Equation 62] 0 < F / ImgH < 1.5

[0375] Mathematical expression 62 can set the total focal length (F) of the optical system (100) and the diagonal length (ImgH) from the optical axis of the sensing unit (151). This optical system (100) can have improved aberration characteristics in the size of the vehicle sensing unit (151). Mathematical expression 62 can preferably satisfy 0.5 < F / ImgH < 1.

[0376] [Equation 63] 0.5 < F / EPD < 1.5

[0377] Mathematical expression 63 can set the overall focal length (F) and entrance pupil size of the optical system (100). Accordingly, the optical system has a small F number, allowing for control of the overall brightness. Mathematical expression 63 preferably satisfies 0.5 < F / EPD < 1.

[0378] [Equation 64] 10 < TTL / F# < 50

[0379] Mathematical expression 64 can set the F number (F#) and the overall optical axis length, thereby controlling the overall size and brightness of the optical system. Mathematical expression 64 preferably satisfies 20 < TTL / F# < 45.

[0380] [Equation 65] 120 < FOV / F# < 270

[0381] Mathematical expression 65 can establish the relationship between the field of view (FOV) and the F number (F#) of an optical system. Mathematical expression 65 can satisfy 150 < FOV / F# < 250. Here, F# can be provided as 1.2 or less or 1 or less to provide a bright image.

[0382] [Equation 66] 20 < (CT_Max+CG_Max)*n < 50

[0383] Preferably, mathematical expression 66 can set the maximum among the central thicknesses of each lens, the maximum among the central spacing between adjacent lenses, and the number of lenses (n).

[0384] [Equation 67] 3 < TTL / n < 8

[0385] Preferably, mathematical expression 67 can set the number of lenses (n) according to the entire optical axis length, and the embodiment can satisfy the condition of 4 < TTL / n < 7.

[0386] [Mathematical Formula 68] 2 < FOV < TTL < 10

[0387] In mathematical expression 68, if the field of view (FOV) and total optical axis length (TTL) of the optical system are satisfied, the optical axis length of the optical system having an angle of view of 110 degrees or more can be set. Accordingly, the chromatic aberration, resolution, size, etc. of the optical system having 7 or fewer lenses can be controlled. Preferably, 4 < FOV < TTL < 8 can be satisfied.

[0388] [Equation 69]

[0389]

[0390] In mathematical expression 71, Z may represent Sag, which is the distance in the direction of the optical axis from any position on the aspherical surface to the vertex of the aspherical surface. Y may represent the distance in the direction perpendicular to the optical axis from any position on the aspherical surface to the optical axis. c may represent the curvature of the lens, and K may represent the conic constant. In addition, A, B, C, D, E, and F may represent aspheric coefficients.

[0391]

[0392] The optical system (100) according to the embodiment can satisfy at least one or two or more mathematical equations from mathematical equations 1 to 68. In this case, the optical system (100) can have improved optical characteristics. Specifically, when the optical system (100) satisfies at least one of mathematical equations 1 to 34 and / or at least one of mathematical equations 35 to 68, the optical system (100) can have improved resolution and improve aberration and distortion characteristics. In addition, the optical system (100) can secure a BFL (Back focal length) for applying a vehicle sensing unit (151), can compensate for optical characteristic degradation due to temperature change, and can minimize the gap between the last lens and the sensing unit (151), thereby having good optical performance at the center and periphery of the field of view (FOV).

[0393] Table 2 shows the items of the mathematical formulas described above in the optical system (100) of the embodiment, including the TTL, BFL, effective focal length (F), ImgH, effective diameter, sum of the center thicknesses of each lens, sum of the center spacings between adjacent lenses, sum of Abbe numbers, sum of refractive indices, TD (mm), which is the optical axis distance from the first surface (S1) to the tenth surface (S10), focal lengths (F1-F6) of each of the first to fifth lenses, composite focal length, FOV, edge thickness (ET), F number, etc. of the optical system (100).

[0394] Item 1 Example 2 Example F (EFL) 2.856 2.846 F1-16.60 3-18.375 F2-18.5 10-16.847 F3-16.9 18-15.962 F4 12.2 20 11.506 F5 13.5 17 13.294 F6 13.5 24 13.783 ΣNd 10.65 110.651 ΣVd 2 78.395 278.395 ΣCT 17.978 17.845 ΣCG 8.2 25 8.485 TTL 3 1.012 30.862F#0.8160.918ET12.6172.162ET22.2672.216ET32.3232.402ET42.4852.205ET51.9131.797ET61.8812. 062FOV190190EPD3.5003.100BFL4.8094.531TD26.20326.330ImgH3.2433.240F13-4.537-4.563F465.1065.165

[0395] Table 3 shows the result values ​​for the mathematical expressions 1 to 34 described above in the optical system (100) of the embodiment. Referring to Table 3, it can be seen that the optical system (100) satisfies at least one, two or more, or three or more of the mathematical expressions 1 to 34. Accordingly, the optical system (100) can have good optical performance and excellent optical characteristics in the center and periphery of the field of view (FOV).

[0396] Mathematical Formula Example 1 Example 2 Example 10.5 < CT1 / CT2 < 1.51.0000.96223 < CA11 / CT111.00010.97030.5 < CT6 / CT5 < 1.51.0001.00040.5 < CT6 / (CT1+CT2) < 1.51.0000.98050.1 < CG3 / CT6 < 10.3810.57960 < CG5 / CG1 < 0.80.4680.69771 < (CA11*L1R1) / (CA31*L3R1) < 51.7371.22282 < (CA11*CT1) / (CA31*CT3) < 63.6673.60195 < TTL / CT_AVER < 2510.35010.377101.70 < Nd11.7411.741113.4 < (Nd1+Nd3) <3.83.5723.572121.7 < Aver(Nd3:Nd6) <2.01.8321.832130.5 < |Ln-1R2 / LnR1| < 1.51.0090.815141 < |Ln-1R1 / LnR2|1.38715.282152 < |Ln-1R2 / CTn-1| < 52.7412.791162 < |LnR1 / CTn| < 52.7173.426175 < AVER(|F1|:|Fn|) < 3015.21515.215181 < CA11 / CA21 < 51.9161.891190 < CA32 / CA41 < 20.9350.929200.8 < CA52 / CA61 < 1.21.0011.020211 < CA11 / CA62 < 51.8651.8302213 < TTL / Nd117.81717.7302310 < CA11 / Nd1 < 3012.63912.605240.2 < CAn-1 / CA3 < 10.4720.461250.5 < CT6 / BFL < 20.8320.883263 < TTL / CG_Max10.75611.244273 < TTL / CT_Max7.7537.7152810 < |L6R2| / CT667.17315.174291 < |L6R2| / L6R1 < 4024.7274.428301 < L1R1 / L1R23.3403.235310.5 < L1R2 / L2R1 <1.50.9970.978320 < CT_Max / CG_Max < 21.3871.457331 < ∑CT / ∑CG < 32.1862.103345 < ∑Nd <1510.65110.651.

[0397] Table 4 shows the result values ​​for the mathematical expressions 35 to 68 described above in the optical system (100) of the embodiment. Referring to Table 4, it can be seen that the optical system (100) satisfies at least one, two or more, or three or more of the mathematical expressions 35 to 68. Accordingly, the optical system (100) can have good optical performance and excellent optical characteristics in the center and periphery of the field of view (FOV).

[0398] Mathematical Formula Example 1 Example 2 510 < ∑Ad / ∑Nd < 5026.13726.1373650 < ∑CT*n < 150107.870107.070372 < CA11 / CA_Min < 53.7433.875383 < CA_Max / CG_Max < 107.6307.994391.5 < |Max_Sag52 | < 32.1352.159405 <|Max_Slope52| < 6534.75634.660411 < CA_Max / (2*ImgH) < 53.3923.386421 < TD / CA_Max < 41.1911.200430 < F / LnR2Jup < 0.50.0110.047440 < F / L1R1 < 0.50.1180.140450 < EPD / LnR2 < 0.50.0130.051460 < EPD / L1R1 < 0.50.1450.152472 < |F1| / F < 85.8136.457480 < |F13| / F46 < 20.8890.883490 < |F1 / F6| < 31.2281.228500 < F4 / F5 < 20.9040.9045120 < TTL31.01230.862522 < ImgH3.2433.240533 < BFL < 204.8094.531541 < F < 152.8562.84655100 < FOV190.000190.000560 < TTL / Ad1 < 10.5930.590575 < TTL / ImgH < 159.5639.525580 < BFL / ImgH < 31.4831.399594 < TTL / BFL < 96.4486.811600 < F / TTL < 0.50.0920.092610 < F / BFL < 10.5940.628620 < F / ImgH < 1.50.8810.878630.5 < F / EPD < 1.50.8160.9186410 < TTL / F# < 5038.00133.61865120 < FOV / F# < 270232.815206.9726620 < (CT_Max+CG_Max)*n < 5041.30040.468673 < TTL / n < 85.1695.144682 < FOV / TTL < 106.1276.157.

[0399]

[0400] Fig. 16 is a block diagram of a sensor device having the optical system according to an embodiment of the invention. Referring to Fig. 16, the sensor device includes a control unit (10), a light source driving unit (20), a transmitting optical system (30), a receiving optical system (50) disclosed above, and a signal processing unit (60).

[0401] The above control unit (10) controls the transmission and reception of signals, and can be linked to devices related to communication services such as autonomous driving modules, artificial intelligence modules, drones, robots, augmented reality devices, virtual phenomenon devices, and 5G and 6G based on the transmitted / received signals.

[0402] The light source driving unit (20) supplies power to and drives the light source included in the transmission optical system (30). The light source generates a laser beam in the form of a line light source or a point light source. The light source driving unit (20) can adjust or vary the driving current supplied to the light source according to driving environment information. The driving environment information can include terrain information of the driving section, traffic congestion information, weather, etc.

[0403] The wavelength of the laser beam generated from the light source may be in the range of 890 nm to 960 nm or in the range of 940 nm ± 10 nm. As another example, the wavelength of the laser beam may be 1550 nm ± 10 nm. The laser light source may be implemented as an InGaAs / GaAs-based semiconductor diode laser and may emit a high-power laser beam. The light source may include a single emitter and / or multiple emitters.

[0404] The above-described transmitting optical system (30) transmits a laser beam generated from a light source to an object (40) through a lens and a diffuser, and the light reflected from the object (40) is received by the receiving optical system (50). The receiving optical system (50) may be composed of a plurality of optical sensors, and the optical sensors convert the received light into an electrical signal using a photodiode. That is, the sensing unit is arranged in a matrix type to convert the light received from an object scanned in each of the horizontal and vertical directions into an electric current.

[0405] The signal processing unit (60) converts the output of the receiving optical system (50) into a voltage, amplifies it, and then converts the amplified signal into a digital signal using an analog-to-digital converter. The signal processing unit (60) analyzes the digital data using a TOF (Time of Flight) algorithm or a phase-shift algorithm to detect the distance to the object (40) and the shape of the object.

[0406] The control unit (10) can receive vehicle speed information and road condition information through a control unit (ECU) or a network. The control unit (10) can receive driving environment information through a network. The driving environment information can include terrain information of the driving section, traffic congestion information, weather, etc. The control unit (10) can adjust the gain based on one or more of the vehicle speed, the road surface condition of the road on which the vehicle is driving, and the driving environment information, and can provide sensor data including the distance to an object and shape information of the object to the free driving device.

[0407]

[0408] Fig. 17 is a drawing showing an example of measuring an object in a vehicle having the sensor system of the invention, and Fig. 18 is a drawing showing an example of surrounding surveillance in a vehicle having the sensor system of the invention.

[0409] Referring to FIGS. 17 and 18, a vehicle (202) having a sensor system includes a transmitting optical system that projects a laser beam (201) generated by a light source toward a target scene, and a receiving optical system that receives light (203) reflected from the target or subject (210). The sensor system also includes a lidar system, which typically includes a controller that calculates distance information to the subject (210) from the reflected light, and an element that can scan or provide a specific pattern of light, which may be a static pattern, within a desired range and field of view (FOV). The transmitting and receiving optical system is used to convert the received signal light into measurements representing a point-by-point three-dimensional map of the surrounding environment within the range and FOV of the lidar system.

[0410] The receiving optics and signal processing for the LIDAR calculate range information based on measurements of the time of flight of the light pulses emitted from the light source. Furthermore, the scene is illuminated at a target plane associated with a specific range, and known information about the light beam profile based on the specific design of the source and projector system is used to determine positional information about the reflecting surfaces, thereby generating a complete x, y, z, or 3D picture of the scene. In other words, the point-by-point 3D map of the surrounding environment represents a collection of measurement data representing positional information from all surfaces reflecting the light from the source to the receiver within the LIDAR system's field of view. In this way, a 3D representation of the object in the LIDAR system's field of view is obtained.

[0411] Also shown is a schematic diagram illustrating the two-dimensional field of view and range requirements of a typical surround-view LIDAR system (200) for a vehicle (202). For example, adaptive cruise control may require a field of view and range (204) with a narrower field of view compared to the side-view "surround view" field of view and range (206), but with a longer range requirement. Typically, a vehicle's sensor functions may be enabled by a combination of LIDAR, radar, cameras, and ultrasonic sensors. The combination of these sensor data to generate information about the surrounding environment is often referred to as "sensor fusion." While the present invention describes a LIDAR system in the context of a vehicle, where LIDAR is widely used for autonomous, self-driving, or driver-assisted vehicles, it should be understood that the embodiments may be applied to any vehicle. Other types of vehicles may include robots, tractors, trucks, airplanes, unmanned aerial vehicles, boats, ships, and the like.

[0412]

[0413] The features, structures, effects, etc. described in the embodiments above are included in at least one embodiment of the present invention, and are not necessarily limited to just one embodiment. Furthermore, the features, structures, effects, etc. illustrated in each embodiment can be combined or modified and implemented in other embodiments by a person having ordinary skill in the art to which the embodiments pertain. Therefore, the contents related to such combinations and modifications should be interpreted as being included in the scope of the present invention. In addition, although the embodiments have been described above, these are merely examples and do not limit the present invention. Those having ordinary skill in the art to which the present invention pertains will appreciate that various modifications and applications not illustrated above are possible without departing from the essential characteristics of the embodiments. For example, each component specifically shown in the embodiments can be modified and implemented. In addition, the differences related to such modifications and applications should be interpreted as being included in the scope of the present invention defined in the appended claims.

Claims

1. A first lens group having first to third lenses aligned along an optical axis from an object toward a sensing unit; A second lens group having fourth to sixth lenses arranged between the first lens group and the sensing unit, The power of the first lens group above is negative, The power of the second lens group is positive, The above first lens has a convex meniscus shape toward the object, The third lens has the smallest effective diameter among the effective diameters of the first to sixth lenses, An optical system in which at least two of the first to sixth lenses have aspherical lenses.

2. In paragraph 1, An optical system in which the refractive index of the first lens is greater than 1.

7.

3. In paragraph 2, An optical system in which the second lens has a refractive index lower than that of the first lens and is made of glass.

4. In paragraph 1, The effective diameter of the first lens is the largest among the effective diameters of the first to sixth lenses.

5. In paragraph 4, An optical system wherein the power of each of the first to third lenses has a negative value.

6. In paragraph 4, An optical system wherein the power of each of the fourth to sixth lenses has a positive value.

7. In paragraph 4, The sensor side surface of the fifth lens has a convex shape, An optical system in which the object-side surface of the sixth lens has a convex shape.

8. In paragraph 7, The average effective diameter of the object side and sensor side of the fifth lens is CA5. The average effective diameter of the object side and sensor side of the above sixth lens is CA6. Mathematical formula: 0.8 < CA5 / CA6 < 1.2 An optical system that satisfies .

9. In paragraph 7, The radius of curvature of the sensor-side surface of the fifth lens is L5R2. The radius of curvature of the object-side surface of the sixth lens is L6R1, Mathematical formula: 0.8 < |L5R2| / L6R1 < 1.2 An optical system that satisfies .

10. In any one of paragraphs 1 to 9, An optical system wherein the third lens has a convex meniscus shape toward the object.

11. In any one of paragraphs 1 to 9, The horizontal angle of view of the above optical system is FOV, The total length of the above optical system is TTL, Mathematical formula: 2 < FOV / TTL < 10 An optical system that satisfies .

12. In any one of paragraphs 1 to 9, The average of the absolute values ​​of the focal lengths of the first to sixth lenses is AVER(|F1|:|F6|), Mathematical formula: 5 < AVER(|F1|:|F6|) < 30 An optical system that satisfies .

13. In any one of paragraphs 1 to 9, The focal length of the above optical system is F, The entrance pupil of the above optical system is EPD, Mathematical formula: 0.5 < F / EPD < 1.5 An optical system that satisfies .

14. In any one of paragraphs 1 to 9, An optical filter disposed between the sensing unit and the sixth lens, The first to sixth lenses are made of glass, The third and fourth lenses are aspherical lenses, The above first, second, fifth, and sixth lenses are spherical lenses in an optical system.

15. An optical system having multiple lenses; sensing unit; It includes an optical filter placed between the optical system and the sensing unit, The optical system has an F number of 1 or less and a horizontal angle of view of 110 degrees or more, The optical system is a lidar device according to any one of claims 1 to 9.

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