Optical system, sensor system and lidar device

Abstract

An optical system according to an embodiment of the present invention disclosed in an embodiment of the present invention comprises: first to sixth lenses aligned along on an optical axis from an object toward a sensing unit; and an optical filter disposed between two adjacent lenses from among the plurality of lenses, wherein with respect to the optical filter, the sensor-side surface of the lens disposed on an object side and the object-side surface of the lens disposed on a sensor side have a convex shape on the optical axis, the object-side surface and the sensor-side surface of the sixth lens have an aspherical shape on the optical axis, the sum of powers of the fourth lens and the fifth lens has a positive value, and the center interval between the fourth lens and the fifth lens from among the center intervals between the first to sixth lenses can be the smallest.

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 increase 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 vehicles is expected to increase as manufacturing costs decline. Ultra-compact and ultra-lightweight LiDAR technology can be used not only as a sensor for unmanned vehicles, but also in satellites and aerospace for geographic and environmental observation, unmanned vehicles, and transporters, cranes, and robots used in factories and shipyards. Furthermore, it is expected to emerge as a form of integrated or collaborative operation between mobile devices through an integrated approach across land, aviation, and marine industries. Therefore, the development of optical systems for ultra-compact and ultra-lightweight LiDAR is urgently needed.

[0004] 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 with improved thermal compensation characteristics.

[0005] An optical system according to an embodiment of the invention includes first to sixth lenses aligned along an optical axis from an object toward a sensing unit; and an optical filter disposed between two adjacent lenses among the plurality of lenses, wherein a sensor-side surface of a lens disposed on the object side and an object-side surface of a lens disposed on the sensor side based on the optical filter have a convex shape on the optical axis, an object-side surface and a sensor-side surface of the sixth lens have an aspherical shape on the optical axis, and a sum of powers of the fourth lens and the fifth lens has a positive value, and among the center distances between the first to sixth lenses, a center distance between the fourth lens and the fifth lens may be the smallest.

[0006] According to an embodiment of the invention, the optical filter may be arranged between the fourth lens and the fifth lens. The first to fifth lenses may be made of glass. The sixth lens may be made of glass. The object-side surface and the sensor-side surface of each of the first to fifth lenses may have a spherical shape on the optical axis. The first lens may have negative refractive power.

[0007] According to an embodiment of the invention, the third lens may have negative refractive power, and the object-side surface and the sensor-side surface of the third lens may have concave shapes on the optical axis. The sixth lens may have positive refractive power, and the object-side surface and the sensor-side surface of the sixth lens may have convex shapes on the optical axis. Among the center distances between the first to sixth lenses, the center distance between the third and fourth lenses may be the largest. The optical axis distance from the sensor-side surface of the optical filter to the imaging surface of the sensing unit is D1, and the optical axis distance from the sensor-side surface of the sixth lens to the imaging surface of the sensing unit is BFL, and the mathematical expression: 2 < D1 / BFL < 6 may be satisfied.

[0008] An optical system according to an embodiment of the invention includes first to sixth lenses aligned along an optical axis from an object toward a sensing unit; an optical filter disposed between two adjacent lenses among the plurality of lenses; and an aperture disposed on an object side relative to the optical filter, wherein the optical filter is disposed on a sensor side relative to two lenses having a maximum center spacing among the lenses, the aperture is disposed around the two lenses having a maximum center spacing among the lenses, and an object-side surface and a sensor-side surface of the sixth lens may have an aspherical shape on the optical axis.

[0009] According to an embodiment of the invention, the optical filter is disposed between the fourth lens and the fifth lens, and the sensor-side surface of the fourth lens may have a convex shape on the optical axis, and the object-side surface of the fifth lens may have a convex shape on the optical axis.

[0010] According to an embodiment of the invention, the first to sixth lenses may be made of glass. The third and fourth lenses may have a concave shape on both sides on the optical axis. The second and sixth lenses may have a convex shape on both sides on the optical axis. The object-side surface and the sensor-side surface of each of the first to fifth lenses may have a spherical shape on the optical axis, and the composite focal lengths of the first to third lenses may have negative values.

[0011] According to an embodiment of the invention, the first lens may have negative refractive power, and the composite focal lengths of the fourth to sixth lenses may have positive values. The focal length of the first lens may be F1, and the effective focal length of the optical system may be F, and the mathematical formula: 1 < |F1| / F < 5 may be satisfied. The optical filter may have a transmittance of 90% or more for some wavelengths within a range of 800 nm to 1000 nm, and the angle of view of the optical system may be 110 degrees or more.

[0012] According to an embodiment of the invention, the first lens has a meniscus shape convex toward the object, an effective diameter of the object-side surface of the first lens is CA11, a central thickness of the first lens is CT1, and the mathematical formula: 7 < CA11 / CT1 < 15 can be satisfied. The F number of the optical system is 1 or less, and the optical filter can be a band pass filter.

[0013] An optical system according to an embodiment may have improved optical characteristics. Specifically, the optical system according to an embodiment may position a bandpass filter near an aperture stop to minimize the incident angle of light incident on the bandpass filter. Accordingly, the transmittance range of the bandpass filter can be broadly utilized depending on the incident angle of light on the bandpass filter.

[0014] The optical system of the inventive lidar can maximize the effect of receiving light emitted from the transmitting optical system. The optical system of the inventive lidar can have good optical characteristics in a low-temperature to high-temperature range. 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. That is, the receiving optical system can effectively perform refractive power distribution in a low-temperature to high-temperature range, and can prevent or minimize changes in optical characteristics in a low-temperature to high-temperature range. Therefore, the optical system and sensor system according to the embodiment can maintain improved optical characteristics in various temperature ranges.

[0015] 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.

[0016] The receiving optical system and sensor system according to the embodiment can satisfy a set angle of view and implement excellent optical characteristics through a combination of spherical and aspherical lenses made of glass. This allows the optical system to provide a slimmer vehicle sensor system. Accordingly, the optical system and sensor system can be provided in various applications and devices, and can maintain 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.

[0017] Fig. 1 is a side cross-sectional view of the optical system of the lidar according to the first embodiment.

[0018] Figure 2 is a table showing the lens characteristics of the optical system of Figure 1.

[0019] Fig. 3 is a table showing the aspherical coefficients of lenses in the optical system of Fig. 1.

[0020] Fig. 4 is a graph showing data of the diffraction MTF (Modulation Transfer Function) of the optical system of Fig. 1.

[0021] Fig. 5 is a graph showing data on the aberration characteristics of the optical system of Fig. 1.

[0022] Fig. 6 is a side cross-sectional view of the optical system of the lidar according to the second embodiment.

[0023] Fig. 7 is a table showing the lens characteristics of the optical system of Fig. 6.

[0024] Fig. 8 is a table showing the aspherical coefficients of lenses in the optical system of Fig. 6.

[0025] Fig. 9 is a graph showing the diffraction MTF data of the optical system of Fig. 6.

[0026] Fig. 10 is a graph showing data on the aberration characteristics of the optical system of Fig. 6.

[0027] Fig. 11 is a block diagram showing a sensor system having the optical systems of Figs. 1 and 6.

[0028] FIG. 12 is a drawing showing an example of measuring an object in a vehicle having a sensor system of the invention.

[0029] Fig. 13 is a drawing showing an example of surrounding surveillance in a vehicle having a sensor system of the invention.

[0030] 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.

[0031] 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.

[0032] 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.

[0033]

[0034] FIG. 1 and FIG. 6 are cross-sectional side views showing an optical system according to an embodiment of the invention.

[0035] Referring to FIGS. 1 and 6, 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).

[0036] 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 total track length (TTL) 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.

[0037]

[0038] 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, a range of 5 to 8 or a range of 5 to 7. The ratio of spherical lenses to aspherical lenses in the n lenses may be any one of 4:1, 5:1, 4:2, 3:3, 5:2, 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 number of spherical lenses may be 3 or more or 4 or more than the number of aspherical lenses.

[0039] 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 external temperature changes, 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 an aspherical lens. Since the nth lens in the optical system (100) is arranged as an aspherical lens, various aberrations of the incident light of the sensing unit (151) may be corrected.

[0040] Within the optical system (100), at least two lenses closest to the object may be formed of glass. Accordingly, since the rate of contraction and expansion due to temperature changes in the lenses adjacent to the outside is smaller than that of plastic lenses, deterioration of optical properties due to temperature changes within the lens barrel can be prevented.

[0041] The optical system (100) above can arrange the last lens (106, 116) closest to the sensing unit (151) as a glass mold material or an aspherical surface, and the last lens (106, 116) has a smaller rate of change in contraction and expansion due to temperature change than a plastic material, so that the optical characteristics can be prevented from being deteriorated due to temperature change within the lens barrel.

[0042]

[0043] 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, and lenses having an object-side aspherical surface and a sensor-side aspherical surface. The number of aspherical lenses in the optical system (100) may be smaller than the number of spherical lenses. The spherical lenses and the aspherical lenses may be made of glass. Among the lenses of the optical system (100), the lens having the maximum refractive index may be a spherical lens arranged between the aspherical lenses, and the lens having the maximum Abbe number may be the third lens (103, 113). Accordingly, since the lens(es) having the maximum refractive index are arranged on the object side of the aspherical lens, it is easy to change the radius of curvature of the last lens and suppress an increase in the effective diameter.

[0044]

[0045] Within the optical system (100), a lens surface having a maximum effective diameter may be arranged on a first lens (101, 111) closest to an object. The first lens (101, 111) may be made of glass and may be a spherical lens. Within the optical system (100), a lens having a minimum effective diameter may be arranged between an aperture (ST) and the first lens (101, 111), or between the aperture (ST) and an image sensor (151). 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), a lens surface having a minimum effective diameter may be closest to the aperture (ST) and may be a spherical surface. Among the lenses between the aperture (ST) and the image sensor (151), a lens surface having a minimum effective diameter may be closest to the image sensor (151) and may be an aspherical surface. Additionally, 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 optical system (100) can be miniaturized.

[0046] 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.

[0047]

[0048] Among the lenses of the optical system (100), the lens having the maximum center thickness may be a spherical lens or an aspherical lens, and the lens having the maximum edge thickness may be a spherical lens or an aspherical lens. The average center thickness of the spherical lenses may be greater than the average center thickness of the aspherical lenses, so that the incident light may be refracted into various paths.

[0049] Within the optical system (100), TTL may be more than 10 times, for example, more than 10 times and less than 20 times, than ImgH (Image height). The TTL (Total track 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) 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). Within the optical system (100), the effective focal length (EFL) is provided to be 15 mm or less and the angle of view (FOV) is provided to be 60 degrees or more or 100 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.

[0050]

[0051] The optical system (100) above can satisfy the condition: 5 < TTL / (2*ImgH) ≤ ​​10. 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 a temperature range that serves as a temperature reliability evaluation standard for automotive electrical components for use in vehicle cameras, that is, from -45°C to +120°C. A lens having heat resistance must be configured so that the focus of the lens remains within a set range even when the lens expands or contracts due to temperature changes. The total effective focal length (EFL) can be 15 mm or less, for example, in a range of 1 mm to 15 mm or a range of 7 mm to 13 mm, and can be configured with lenses made of glass that can perform the aforementioned temperature compensation. By shortening the effective focal length of the optical system, a wide angle can be realized.

[0052] 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 difference between the average refractive index of the lenses having negative refractive power and the average of the lenses having positive refractive power may be 0.2 or more or 0.5 or more. The dispersion value of the lenses having positive refractive power may be greater than the dispersion value of the lenses having negative refractive power. Since the optical system (100) is a mixture of a spherical lens and an aspherical lens made of glass, various aberrations can be corrected, thereby preventing deterioration of optical performance.

[0053] In the above optical system (100), the number of aspherical lenses may be equal to or 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.

[0054]

[0055] The optical system (100) may include an optical filter (155), and the optical filter (155) may be disposed between two lenses that are opposed to each other along an optical axis. The optical filter (155) may be disposed between two different lenses among the lenses. The optical filter (155) may be disposed between two lenses having a small difference in effective diameter, and the difference in effective diameter may be 10 mm or less. The optical filter (155) may be disposed between spherical lenses. The optical filter (155) may be disposed between the fourth lens (104, 114) and the fifth lens (105, 115). The optical filter (155) 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 (155) may be a bandpass filter.

[0056]

[0057] The optical filter (155) may 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 (155) may actively perform the filtering operation. To this end, the optical filter (155) may 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 (155) may include information about the center wavelength of the light to pass through the active device, wherein the center wavelength may correspond to the center wavelength of the light emitted from the transmission optical system. Consequently, the control signal provided to the optical filter (155) 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 (155). Due to the active device included in the optical filter (155), the optical filter (155) 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 can include a tunable band-pass filter. The operating method of the tunable band-pass filter can be a liquid crystal method or an acousto-optic method.

[0058] The optical filter (155) is a TOF optical system that uses a specific wavelength or a designated wavelength band, and can suppress the generation of stray light by blocking light outside the designated wavelength band from entering the sensor unit. Therefore, since at least one lens is arranged between the optical filter (155) and the sensor unit (151), the generation of stray light can be suppressed. That is, since visible light outside the wavelength band is blocked by the lens(es) between the optical filter (155) and the sensor unit (151), the blocked visible light can be suppressed from being refracted, reflected, or / and scattered by the lens(es) between the optical filter (155) and the sensor unit (151).

[0059]

[0060] The optical system (100) and the 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 configuring such a bright optical system, the camera module may include at least 5 lenses, and may be miniaturized and achieve good optical performance by at least one aspherical lens. The sum of the refractive indices of the lenses in the optical system (100) may be greater than 7, for example, 8.0 or more, 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 250 or less, for example, in the range of 150 to 250 or in the range of 180 to 240, and the average of the Abbe numbers may be 47 or less, for example, in the range of 23 to 47. By adjusting the refractive index of the lenses within the optical system (100), it is possible to prevent degradation of optical performance for temperature changes from -45 to 120 degrees and optimize thermal compensation. In addition, by adjusting the Abbe number, it is possible to minimize the deviation in the spot size of incident light, i.e., to minimize the spot diagram size.

[0061] The sum of the central thicknesses of all lenses within the optical system (100) may be 50 mm or more, for example, in the range of 50 mm to 95 mm or 60 mm to 90 mm, and the average of the central thicknesses of each lens may be 18 mm or less, for example, in the range of 9 mm to 18 mm. The sum of the central spacings between the lenses along the optical axis (OA) may be 30 mm or more, for example, in the range of 30 mm to 75 mm, and may be less 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.

[0062] In an optical system according to an embodiment of the invention, the angle of view may be 110 degrees or more, for example, in a range of 110 degrees or more to 150 degrees, preferably, in a range of 120 degrees to 140 degrees. The diagonal length of the sensing unit (151) may be 14 mm or more, for example, in a range of 14 mm to 22 mm or 19 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.

[0063]

[0064] The embodiment includes an optical system applied to a lidar device, and the first lens (101, 111) may be provided as 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 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). 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.

[0065]

[0066] Hereinafter, an optical system according to a first embodiment of the invention will be described. Fig. 1 is a side cross-sectional view of an optical system of a lidar according to the first embodiment, Fig. 2 is a table showing lens characteristics of the optical system of Fig. 1, Fig. 3 is a table showing aspherical coefficients of lenses in the optical system of Fig. 1, Fig. 4 is a graph showing data of diffraction MTF of the optical system of Fig. 1, and Fig. 5 is a graph showing data on aberration characteristics of the optical system of Fig. 1.

[0067] Referring to FIGS. 1 to 3, 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 (155), and the optical filter (155) may be arranged between the lenses. The optical filter (155) may be arranged between the spherical lenses. The optical filter (155) may be arranged between two lenses excluding a lens having a maximum effective diameter and a lens having a minimum effective diameter. The difference between the effective diameter of a lens arranged on the object side and a lens arranged on the sensor side based on the optical filter (155) may be 10 mm or less.

[0068] Light corresponding to object information can pass through the first lens (101) to the fourth lens (104), the optical filter (155), and the fifth and sixth lenses (105, 106) and be incident on the sensing unit (151). The aperture (ST) may be arranged around the sensor-side surface of the third lens (103) or the object-side surface of the fourth lens (104). The aperture (ST) may be arranged between the optical filter (155) and the first lens (101). 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 aperture (ST) may be arranged between the optical filter (155) and the first lens group. Here, the first lens group includes first to third lenses (101, 102, 103) 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 image sensor (151). The second lens group may include the optical filter (155).

[0069]

[0070] Each of the first to sixth lenses (101-106) may have positive (+) or negative (-) refractive 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. The first lens (101) may have positive (+) or negative (-) refractive power, and preferably, negative (-) refractive power. The first lens (101) may be made of glass. 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 surface of the optical system (100). The first lens (101) is made of a glass material that is not injection molded. On the optical axis (OA), the first surface (S1) on the object side of the first lens (101) may be convex, and the second surface (S2) on the sensor side may be concave. On the optical axis (OA), the first surface (S1) and the second surface (S2) may be spherical. The first lens (101) may have a meniscus shape that is convex toward the object side. Alternatively, the first surface (S1) may have a concave shape, and the second surface (S2) may have a convex shape on the optical axis (OA). Alternatively, the first lens (101) may have a concave shape on both sides. Since the first surface (S1) has a convex shape and the second surface (S2) has a concave shape, 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 the effective diameter of the second lens (102) can be reduced. 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).

[0071] When the refractive index of the first lens (101) is Nd1, the condition of 1.7 < Nd1 or 1.75 < Nd1 < 2.1 can be satisfied. Since the refractive index (Nd1) of the first lens (101) is greater than the refractive index of the aspherical sixth lens (106), the radius of curvature of the first surface (S1) of the first lens (101) can be increased. When the refractive index (Nd1) of the first lens (101) is less than the above condition, the lens surface must be formed to be sharply concave or convex in order to increase the refractive power of the first and second lenses (101, 102). In this case, lens manufacturing is not easy, the lens defect rate increases, and this may cause a decrease in yield.

[0072]

[0073] The second lens (102) may be disposed 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 positive (+) refractive power. The second lens (102) may be a spherical lens made of glass. The object-side third surface (S3) of the second lens (102) on the optical axis (OA) may be convex, and the sensor-side fourth surface (S4) may be convex. The third and fourth surfaces (S3, S4) on the optical axis (OA) may be spherical, and alternatively, the third surface (S3) may be convex, and the fourth surface (S4) may have a concave shape. Alternatively, the second lens (102) may have a convex meniscus shape toward the sensor or a concave shape on both sides.

[0074] 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 a spherical lens made of glass. On the optical axis, the fifth surface (S5) on the object side of the third lens (103) may be concave, and the sixth surface (S6) on the sensor side may be concave. On the optical axis (OA), the third lens (103) may have a shape in which both sides are concave on the optical axis (OA). Alternatively, the third lens (103) may have a meniscus shape that is convex on the object side or the sensor side. Alternatively, the third lens (103) may have a shape in which both sides are convex on the optical axis. At least one or both of the fifth surface (S5) and the sixth surface (S6) may be spherical. When the refractive index of the third lens (103) is Nd3, the condition of Nd3 < Nd2 can be satisfied. When the Abbe number of the third lens (103) is Vd3, the condition of Vd2 < Vd3 can be satisfied. Nd2 is the refractive index of the second lens (102), and Vd2 is the Abbe number of the second lens (102). In the specification, each refractive index is the refractive index at the D-line.

[0075] The aperture (ST) may be arranged around the periphery of the sixth surface (S6) on the sensor side of the third lens (103) or the periphery of the seventh surface (S7) on the object side of the fourth lens (104). 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 increase the distance between the third lens (103) and the fourth lens (104). Accordingly, the effective diameter of the fourth lens (104) may be larger than that of the third lens (103). Here, the powers of the fourth, fifth, and sixth lenses (104, 105, and 106) arranged on the sensor side of the aperture (ST) may have positive values, and the optical system may reduce the TTL within the field of view range.

[0076]

[0077] 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 a spherical lens. On the optical axis, the seventh surface (S7) on the object side of the fourth lens (104) may be convex, and the eighth surface (S8) on the sensor side may have a convex shape. The fourth lens (104) may be convex on both sides. Alternatively, the fourth lens (104) may have a meniscus shape that is convex toward the object. Alternatively, the fourth lens (104) may have a meniscus shape that is convex toward the sensor. 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) may be spherical. The sensor-side eighth surface (S8) of the fourth lens (104) may have a convex shape and may have a radius of curvature (absolute value) that is larger than the effective diameter of the third lens (103) and larger than the radius of curvature of the sixth surface (S6) of the third lens (103). Accordingly, the distance between the fourth lens (104) and the aperture (ST) may be smaller than the center distance between the aperture (ST) and the third lens (103).

[0078] The optical filter (155) arranged between the fourth lens (104) and the fifth lens (105) can reduce light loss because the difference in effective diameter of the fourth and fifth lenses (104, 105) can be 5 mm or less. The optical filter (155) transmits a laser beam reflected by a subject after being emitted from the transmission optical system of the lidar device, and blocks beams of other wavelengths. The optical filter (155) can be arranged within the second lens group to transmit a designated wavelength band and block wavelength bands outside of the designated wavelength band.

[0079] 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, the ninth surface (S9) on the object side of the fifth lens (105) may be convex, and the tenth surface (S10) on the sensor side may have a concave shape. The fifth lens (105) may have a meniscus shape that is convex toward the object. 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 sensor (i.e., the image sensor). 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.

[0080] On the optical axis, the radius of curvature of the eighth surface (S8) of the fourth lens (104) is larger than the radius of curvature of the sixth surface (S6), for example, it may be at least twice the radius of curvature of the sixth surface (S6) or in a range of three to six times the radius of curvature of the sixth surface (S6). On the optical axis, the radius of curvature of the eighth surface (S8) may be larger than the absolute value of the radius of curvature of the ninth surface (S9), for example, it may be at least 1.5 times or in a range of 1.5 to 3 times. Accordingly, the center spacing (CG3) between the third and fourth lenses (103, 104) is increased, and the incident angle of light incident on the optical filter (155) through the third and fourth lenses (103, 104) can be refracted to be close to 0. In addition, the center thickness (CT4) of the fourth lens (104) can be made thicker than the center thicknesses (CT1, CT2, CT3) of the first, second, and third lenses (101, 102, 103), thereby reducing changes in the path of light.

[0081] The sum of the powers of the fourth and fifth lenses (104, 105) has a positive value, the sum of the powers of the third and fourth lenses (103, 104) is close to 0, and the angle of incidence of light incident on the optical filter (155) through the third and fourth lenses (103, 104) can be controlled to be close to 0 by the lens shapes of the first to third lenses (101, 102, 103). The center spacing (CG3) between the third and fourth lenses (103, 104) is 10 mm or more, and the third lens (103) can refract the emitted light from the optical axis toward the edge, so that the optical system can have a low F number. When the F number is less than 1.2, for example, 1 or less, the optical system can provide a bright image. In addition, 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). The center spacing (CG4) between the fourth and fifth lenses (104, 105) may be three times or less, for example, 2.5 times or less, of the thickness of the optical filter (155), thereby reducing the TTL.

[0082]

[0083] The sixth lens (106) may have a positive (+) refractive power. The sixth lens (106) may include a glass material. The sixth lens (106) may be an aspherical lens. On the optical axis, the object-side eleventh surface (S11) of the sixth lens (106) may be convex, and the sensor-side twelfth surface (S12) may have a convex shape. The sixth lens (106) may have a convex shape on both sides on the optical axis. Alternatively, 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 (i.e., the image sensor). At least one or both of the ninth surface (S9) and the tenth surface (S10) are aspherical, and, like L6S1 and L6S2 of FIG. 3, have a curvature It can have a radius (R), a conic constant (K), and a 4th to 16th aspherical coefficient (AG). By this aspherical lens, distortion aberration can be reduced, and for yield, the center thickness (CT6) of the sixth lens (106) can be larger than the center thickness (CT2) of the second lens (102). The 11th and 12th surfaces (S11, S12) of the sixth lens (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 mean 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 the tangent passing through the lens surface increases and then decreases, or a point where it decreases and then increases.

[0084]

[0085] When the refractive index of the sixth lens (106) is Nd6, the condition of Nd6 < Nd5 can be satisfied. When the Abbe number of the sixth lens (106) is Vd6, the condition of Vd5 < Vd6 can be satisfied. Nd5 is the refractive index of the fifth lens (105), and Vd5 is the Abbe number of the fifth lens (105). The first, second, fourth, and fifth lenses (101, 102, 104, and 105) may be made of the same material, or may be made of a material having a refractive index difference of 0.10 or less. The sixth lens (106) may have a refractive index lower than that of the fourth and fifth lenses (104 and 105), and an Abbe number higher than that of the fourth and fifth lenses (104 and 105).

[0086] The effective diameter of the sixth lens (106) may be smaller than the effective diameter of the fifth lens (105). 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 eighth surface (S8). 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 twelfth surface (S12). The lens surface with the largest effective diameter among the object-side and sensor-side surfaces is the first surface (S1), and the lens surface with the smallest effective diameter is the twelfth surface (S12). 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 total focal length, so that an optical system (100) having a small F number and a bright image can be provided.

[0087]

[0088] 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 optical characteristics due to resolution and temperature change, improve chromatic aberration control characteristics, and improve the vignetting characteristics of the optical system (100). The optical filter (155) can 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 can 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.

[0089]

[0090] The fourth lens (104) is disposed on the object side of the optical filter (155), has a refractive index greater than that of the third lens (103), and may have a center thickness (CT4) greater than that of the first lens (101). The fifth lens (105) is disposed on the sensor side of the optical filter (155), has a refractive index greater than that of the sixth lens (106), and may have a center thickness (CT6) greater than that of the first lens (101). The center spacing (CG3) between the third and fourth lenses (103, 104) is greater than the center spacing (CG4) between the fourth and fifth lenses (104, 105) on which the optical filter (155) is disposed, and may be the largest among the center spacings between adjacent two lenses within the optical system (100).

[0091] When the radius of curvature of each lens surface is described in absolute values ​​on the optical axis, the lens surface having the minimum radius of curvature may be the second surface (S2) of the first lens (101). The lens surface having the maximum radius of curvature may be the first surface (S1) of the first lens (101). Accordingly, the amount of incident light of the first lens (101) is increased, and the center distance between the first and second lenses (101, 102) is the largest among the areas between the first and second lenses (101, 102), so that an increase in the effective diameter of the second lens (102) can be suppressed. In absolute values, the lens having the largest difference in the radius of curvature between the object-side surface and the sensor-side surface of each lens is the first lens (101), and the lens having the smallest difference in the radius of curvature is the third lens (103). Accordingly, when the radius of curvature of the first and third lenses (101, 103) is adjusted, lens ghosting can be reduced by preventing irregular reflection between adjacent lens surfaces, and multi-path interference (MPI) caused by lens ghosting can be prevented. Since the object-side first surface (S1) of the first lens (101) is provided with a radius of curvature of 300 mm or more, for example, more than 10 times 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.

[0092]

[0093] 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, there may be no lens surface having an effective diameter smaller than the effective length of the sensing unit (151).

[0094]

[0095] At least two lenses may be arranged between the optical filter (155) and the sensing unit (151). For example, the fifth and sixth lenses (106, 106) may be arranged between the optical filter (155) and the sensing unit (151). A spherical lens and an aspherical lens may be arranged between the optical filter (155) and the sensing unit (151). The optical filter (155) may be arranged between the spherical fourth lens (104) and the spherical sixth lens (105). The optical filter (155) may be arranged between the eighth surface (S8) of the fourth lens (104) and the tenth surface (S10) of the fifth lens (105). The optical filter (155) may have a transmittance of 90% or more for at least a portion of a wavelength band ranging from 800 nm to 1000 nm. The optical filter (155) may be, for example, a band pass filter that passes a laser beam in the range of 890 nm to 960 nm or 940 nm ± 10 nm. As another example, the optical filter (155) may transmit a range of 1550 nm ± 10 nm and block other wavelengths. The optical filter (155) may pass a wavelength corresponding to a laser beam transmitted from a transmission optical system of a lidar device and block light corresponding to the remaining ambient light.

[0096] The cover glass (153) is placed between the last lens and the sensing unit (151), and protects the upper portion of the sensing unit (151) and can prevent the reliability of the sensing unit (151) from being deteriorated. The cover glass (153) can be removed. The cover glass (153) may be a protective glass.

[0097] 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.

[0098]

[0099] The refractive power of the first lens group having the first to third lenses (101-103) may have a negative (-) 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. That is, the first lens group having the first to third lenses (101-103) may have a negative (-) power, and the second lens group having the fourth to sixth lenses (104-106) may have a positive power. In addition, the composite refractive powers of the fourth and fifth lenses (104, 105) on both sides of the optical filter (155) may have a positive (+) value.

[0100] As shown in FIGS. 1 and 2, the center thickness of the first to sixth lenses (101-106) is represented by CT1-CT6, the edge thickness at the end of the effective area of ​​each lens is represented by ET1-ET6, and the center gap between two adjacent lenses is represented by CG1-CG5. The first to sixth lenses (101-106) can satisfy the following conditions, and * indicates multiplication.

[0101] Condition 1: CT1 < CT4

[0102] Condition 2: CT1*2 < CT2

[0103] Condition 3: (CT5-CT4) < (CT5-CT6)

[0104] Condition 4: CT3*3 < CT4

[0105] Condition 5: ET3 < ET2 < ET1

[0106] Condition 6: ET3 < ET4 < ET6 < CT5

[0107] The center thickness (CT5) of the fifth lens (105) is the maximum among the center thicknesses of the lenses, and the center thickness (CT3) of the third lens (103) is the minimum among the center thicknesses of the lenses. The maximum center thickness may be more than three times the minimum center thickness, and the difference between the maximum center thickness and the minimum center thickness may be 4 mm or more. By adjusting the center thickness of these lenses, the sensor system can be provided with a slim thickness, and thermal compensation can be provided for temperatures that change from low to high temperatures.

[0108] If the center spacings between adjacent lenses (CG1-CG5) are described, the following conditions can be satisfied.

[0109] Condition 1: CT1 < CG1 Condition 2: CG2 < CG1 < CG2*3

[0110] Condition 3: CG2 < CG3 Condition 4: CG4 < CG2 < CG4*2

[0111] Condition 5: CT4 < CG3 < CT5 Condition 6: CG6*2 < CG4

[0112] Condition 7: (CT1+CT3) < CG3

[0113] Here, the difference between the maximum center spacing and the minimum center spacing may be 5 mm or more, for example, in the range of 5 mm to 20 mm. Furthermore, by providing the maximum center spacing between the lenses to be less than the maximum center thickness of each lens, a receiving optical system can be provided in which the center spacing between the spherical lens and the aspherical lens is not large. Furthermore, since the maximum center spacing between the lenses is provided to be more than three times the minimum center thickness of each lens, the optical path can be controlled.

[0114]

[0115] 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.

[0116] Condition 1: CA12 < CA11 < CA12*2 Condition 2: CA3 < CA2 < CA1

[0117] Condition 3: CA6 < CA5 < CA4 Condition 4: CA3 < CA4 < CA1

[0118] Condition 5: 0.5 < CA4 / CA5 < 1.5 Condition 6: 0.5 < CA42 / CA41 < 1.5

[0119] Condition 7: 0.5 < CA51 / CA52 < 1.5 Condition 8: 0.5 < CA61 / CA62 < 1.5

[0120] The lens having the maximum effective diameter may be the first lens (101). The first lens (101) having the maximum effective diameter may be a spherical lens made of glass. The lens surface having the maximum effective diameter may be the first surface (S1) of the first lens (101). The lens having the lens surface having the minimum effective diameter may be the twelfth surface (S12) of the sixth lens (106), and may be less than 0.6 times the size of the first surface (S1). The effective diameter of each of the first to sixth lenses (101-106) may be greater than the diagonal length of the effective area of ​​the sensing unit (151). The sixth lens (106) has an aspherical surface and can guide light incident through the fifth lens (105), which is a spherical lens, to the entire area of ​​the sensing unit (151).

[0121]

[0122] FIG. 2 is an example of lens data of the optical system of the embodiment of FIG. 1. As shown in FIG. 2, the radius of curvature (Radius of Curvature) of 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 (Refractive index) at the d-line, the Abbe number, and the size of the effective diameter can be set. As shown in FIG. 3, the lens surface of the sixth lens (106) among the lenses of the embodiment of FIG. 1 may include an aspherical surface having a radius of curvature (R), a conic constant (K), and a 16th-order aspherical surface coefficient (AG). For example, since an aspherical surface having a 16th-order aspherical surface coefficient (a non-zero value) as described above can significantly change the aspherical shape of the periphery, the optical performance of the periphery of the field of view (FOV) can be well corrected.

[0123] The focal lengths (F1, F3) of the first and third lenses (101, 103) may have negative refractive power, and the focal lengths (F2, F4, F5, F6) of the second, fourth, fifth, and sixth lenses (102, 104, 105, 106) may have positive refractive power. In addition, the third lens (103) and the fourth lens (104), which are adjacently arranged lenses, may satisfy the following conditions.

[0124] Condition 1: Refractive index of lens with positive refractive power > refractive index of lens with negative refractive power

[0125] Condition 2: Dispersion of a lens with positive refractive power < Dispersion of a lens with negative refractive power

[0126] Here, among the lenses, the third lens (103) has negative refractive power, and the fourth lens (104) has positive refractive power, so that according to conditions 1 and 2, the refractive index of the fourth lens (104) is greater than the refractive index of the third lens (103), and the dispersion value of the fourth lens (104) is less than the dispersion value of the third lens (103). The chromatic aberration occurring in the spherical lens can be corrected by the spherical lens. In addition, by satisfying that the refractive index difference between the fourth lens (104) and the fifth lens (105), which are spherical lenses arranged in succession, is 0.1 or less and the Abbe number difference is 10 or less, the chromatic aberration occurring in the spherical lens can be compensated for by the spherical lens. The refractive power (F1-F6) and the total focal length (F) of each lens can satisfy the following conditions.

[0127] Condition 1: │F1│ < F2 Condition 2: │F3│ < │F1│

[0128] Condition 3: 0.5 < │F1│ / │F3│ < 1.5

[0129] Condition 4: F6 < F4 < F5 Condition 5: F < F5

[0130] Condition 6: F < │F1│ Condition 7: F < BFL

[0131] Here, F is the effective focal length of the optical system, and BFL is the optical axis distance between the last lens, i.e., the sixth lens (106), and the surface of the image sensor, which is the sensor unit (151). The focal length of the second lens (102) is the largest among the lenses, and may be 50 mm or more and 100 mm or less. 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.

[0132] The composite focal length of the first and second lenses is F12, the composite focal length of the third to sixth lenses is F36, the composite focal length of the first to third lenses is F13, and the composite focal length of the fourth to sixth lenses is F46, and the following conditions can be satisfied.

[0133] Condition 1: F36 < │F12│ (where F12 < 0)

[0134] Condition 2: │F13│ < F46 < │F13│*3

[0135] Condition 3: F < F25 < F2 < F14

[0136] Condition 4: 0 < F45 < F24

[0137] Here, F is the overall focal length, F14 is the composite focal length of the first to fourth lenses, F24 is the composite focal length of the second to fourth lenses, F25 is the composite focal length of the second to fifth lenses, and F45 is the composite focal length of the fourth and fifth lenses.

[0138]

[0139] 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.

[0140] Condition 1: CA12*2 < TTL Condition 2: F2 < TTL

[0141] Condition 3: 0.5 < TTL / FOV < 1.5 or 1 < TTL / FOV < 1.5

[0142]

[0143] Fig. 4 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. 4 shows the diffraction MTF at room temperature, and is a graph measuring the luminance ratio according to the position of the defocusing position. Fig. 5 is a graph showing the aberration characteristics in the optical system of Fig. 1. In the aberration graph of Fig. 5, it is a graph measuring spherical aberration (longitudinal spherical aberration), astigmatic field curves, and distortion from left to right. In Fig. 5, the X-axis can represent the focal length (mm) and the degree of distortion (%), and the Y-axis can represent the height of the image. In addition, the graph for spherical aberration is a graph for light in the wavelength bands of about 930 nm, about 940 nm, and about 950 nm, and the graph for astigmatism and distortion is a graph for light in the wavelength band of about 940 nm. In the aberration diagram of Fig. 5, 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).

[0144]

[0145] Hereinafter, 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. Fig. 6 is a side cross-sectional view of an optical system of a lidar device according to the second embodiment, Fig. 7 is a table showing lens characteristics of the optical system of Fig. 6, Fig. 8 is a table showing aspherical coefficients of lenses in the optical system of Fig. 6, Fig. 9 is a graph showing data of diffraction MTF of the optical system of Fig. 6, and Fig. 10 is a graph showing data on aberration characteristics of the optical system of Fig. 6. Referring to Figs. 6 to 8, the optical system (100) may include first lenses (111) to sixth lenses (116) and an optical filter (155). The first to sixth lenses (111-116) may include a glass material. The first and third lenses (111, 113) may have negative refractive power. The second, fourth, fifth, and sixth lenses (112, 114, 115, 116) may have positive refractive power.

[0146] 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) may have spherical surfaces. When the refractive index of the first lens (111) is Nd1, the condition of 1.7 < Nd1 or 1.75 < Nd1 < 2.1 may be satisfied. The second lens (112) may be a spherical lens made of glass. The third surface (S3) on the object side of the second lens (112) may be convex, and the fourth surface (S4) on the sensor side may be convex. The third and fourth surfaces (S3, S4) may be spherical surfaces. When the refractive index of the second lens (112) is Nd2, the condition of 1.7 < Nd2 or 1.75 < Nd2 < 2.1 may be satisfied. The center spacing between the second and third lenses (112, 113) can be reduced by the shape of the second lens (112).

[0147] The third lens (113) may be a spherical lens made of glass. The object-side fifth surface (S5) of the third lens (113) may be concave, and the sensor-side sixth surface (S6) may be concave. At least one or both of the fifth surface (S5) and the sixth surface (S6) may be spherical. When the refractive index of the third lens (113) is Nd3, the condition of Nd3 < Nd2 may be satisfied. When the Abbe number of the third lens (113) is Vd3, the condition of Vd2 < Vd3 may be satisfied. The sensor-side sixth surface (S6) of the third lens (113) has a concave shape and has a radius of curvature smaller than the absolute value of the radius of curvature of the fourth surface (S4), so that the center distance between the third lens (113) and the fourth lens (114) may be the largest among the center distances between lenses.

[0148] The fourth lens (114) may be a spherical lens. The object-side seventh surface (S7) of the fourth lens (114) may be convex, and the sensor-side eighth surface (S8) may have a convex shape. The fourth lens (114) may have a convex shape on both sides. At least one or both of the seventh surface (S7) and the eighth surface (S8) may be spherical. The aperture (ST) may be arranged between the third and fourth lenses (113, 114). The aperture (ST) may be arranged around the object-side seventh surface (S7) of the fourth lens (114). The aperture (ST) may be arranged closer to the object-side surface of the fourth lens (114) than to the sensor-side surface of the third lens (113). The effective diameter of the object-side surface (S1) of the optical filter (155) located on the sensor side of the fourth lens (114) may be smaller than the effective diameter of the eighth surface (S8) of the fourth lens (114), and the effective diameter of the sensor-side surface (S2) may be larger than the effective diameter of the object-side surface (S9) of the fifth lens (115). Accordingly, light passing through the optical filter (115) via the fourth lens (114) may be provided to the entire area of ​​the fifth lens (115) as nearly parallel light.

[0149]

[0150] The fifth lens (115) may be a spherical lens. On the optical axis, the ninth surface (S9) on the object side of the fifth lens (115) may have a convex shape, and the tenth surface (S10) on the sensor side may have a concave shape. The fifth lens (115) may have a meniscus shape that is convex toward the object. At least one or both of the ninth surface (S9) and the tenth surface (S10) may be spherical.

[0151] The sixth lens (116) may be an aspherical lens. On the optical axis, the object-side eleventh surface (S11) of the sixth lens (116) may be convex, and the sensor-side twelfth surface (S12) may have a convex shape. The sixth lens (116) may have a convex shape on both sides. At least one or both of the eleventh surface (S11) and the twelfth surface (S12) may be aspherical. The aspherical coefficients of the eleventh and twelfth surfaces (S11, S12) may be provided as L6S1 and L6S2 of FIG. 8. The sixth lens (116) may be an aspherical lens closest to the sensing unit (151). By using the lens surfaces (S11, S12) having aspherical surfaces, aberrations such as spherical aberration and chromatic aberration can be improved, and the influence on resolution can be controlled. The optical performance can be improved by the aspherical surface of the lens surface (S11, S12) adjacent to the sensing unit (151), for example, the aberration characteristics can be improved and the resolution can be prevented from being degraded. The first surface (S11) of the sixth lens (116) can be provided without a critical point from the optical axis to the end of the effective area or can have at least one critical point. The twelfth surface (S12) can be provided without a critical point from the optical axis to the end of the effective area.

[0152]

[0153] When the refractive indices of the fourth and fifth lenses (114, 115) are Nd4 and Nd5, the condition of Nd5 < Nd4 can be satisfied. When the Abbe numbers of the fourth and fifth lenses (114, 115) are Vd4 and Vd5, the condition of Vd4 < Vd5 can be satisfied. The first, second, and fourth lenses (111, 112, 114) may be made of the same material or may be made of a material having a refractive index difference of 0.15 or less. The material of the third lens (113) may have the lowest refractive index among the lenses. The sixth lens (116) may have a refractive index lower than the refractive indices of the fourth and fifth lenses (114, 115) and an Abbe number lower than the Abbe number of the fourth and fifth lenses (114, 115).

[0154] The effective diameter of the sixth lens (116) may be smaller than the effective diameter of the fifth lens (115). The effective diameter of the first lens (111) 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 eighth surface (S8). The lens surface with the smallest effective diameter among the object-side surfaces of the lenses may be the fifth surface (S5) or the eleventh surface (S11), and the lens surface with the smallest effective diameter among the sensor-side surfaces of the lenses may be the twelfth surface (S12). The lens surface with the largest effective diameter among the object-side and sensor-side surfaces is the first surface (S1), and the lens surface with the smallest effective diameter is the twelfth surface (S12).

[0155] The effective diameter of the first lens (111) may be larger than the effective diameter of the sixth lens (116) closest to the sensing unit (151). Accordingly, the brightness of the optical system (100) can be controlled. 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 resolution and optical characteristics due to temperature changes, improve the chromatic aberration control characteristics, and improve the vignetting characteristics of the optical system (100). As another example, at least one of the object-side surface and the sensor-side surface of the sixth lens (116) may have a free-form surface, i.e., a non-rotationally symmetrical surface.

[0156] The fourth lens (114) is disposed on the object side of the optical filter (155), has a refractive index greater than that of the third lens (113), and may have a center thickness (CT4) greater than that of the first and third lenses (111, 113). The fifth lens (115) is disposed on the sensor side of the optical filter (155), has a refractive index greater than that of the sixth lens (116), and may have a center thickness (CT5) greater than that of the first and third lenses (111, 113). The absolute value difference in the radius of curvature of the object-side surface and the sensor-side surface of the fourth lens (114) has a difference of 10 mm or less, for example, 5 mm or less, and is arranged on the object-side of the optical filter (155), so that the incident angle of light incident on the optical filter (155) can be adjusted and the occurrence of stray light can be suppressed. The center spacing (CG2) between the second and third lenses (112, 113) may be greater than the center spacing (CG4) between the fourth and fifth lenses (114, 115) on which the optical filter (155) is arranged. The center spacing (CG3) between the third and fourth lenses (113, 114) may be the largest among the center spacings between adjacent two lenses within the optical system (100).

[0157]

[0158] When the radius of curvature of each lens surface on the optical axis is described as an absolute value, the lens surface having the minimum radius of curvature may be the second surface (S2) of the first lens (111). Since the radius of curvature of the first surface (S1) of the first lens (111) is provided to be 300 mm or more, the amount of incident light of the first lens (111) is increased, and the center distance (CG1) between the first and second lenses (111, 112) is the largest among the areas between the first and second lenses (111, 112), so that an increase in the effective diameter of the second lens (112) can be suppressed. In addition, the lens surface having the maximum radius of curvature may be the first surface (S1) of the first lens (111). Accordingly, the F number of the optical system can be provided to be 1 or less. The lens with the largest difference in the radius of curvature (absolute value) between the object-side surface and the sensor-side surface of each lens is the first lens (111), and the lens with the second largest difference is the second lens (112). Since the difference in the radius of curvature between the first surface (S1) and the second surface (S2) of the first lens (111) is provided to exceed 20 times, distortion of reflected light can be reduced, and the depth of field can be further increased, thereby improving image quality under low-light conditions.

[0159] At least two lenses may be arranged between the optical filter (155) and the sensing unit (151). For example, the fifth and sixth lenses (115, 116) may be arranged between the optical filter (155) and the sensing unit (151). A spherical lens and an aspherical lens may be arranged between the optical filter (155) and the sensing unit (151). The optical filter (155) may be arranged between the spherical fourth lens (114) and the spherical fifth lens (115). A cover glass (153) is arranged between the last lens and the sensing unit (151), and may protect the upper portion of the sensing unit (151) and prevent a decrease in the reliability of the sensing unit (151).

[0160] As shown in FIGS. 6 and 7, the first to sixth lenses (111-116) can satisfy the following conditions, and * means multiplication.

[0161] Condition 1: CT1 < CT2 Condition 2: CT3*2 < CT4

[0162] Condition 3: (CT5-CT4) < (CT2-CT3) Condition 4: CT1*2 < CT5 < CT6

[0163] Condition 5: ET2 < ET3 < ET1 Condition 6: ET5 < ET6 < CT6

[0164] The center thickness (CT6) of the sixth lens (116) is the largest among the lenses, and the center thicknesses (CT1, CT3) of the first and third lenses (111, 113) are the smallest among the lenses. The maximum center thickness may be more than twice the minimum center thickness, and the difference between the maximum center thickness and the minimum center thickness may be 4 mm or more. That is, the center thickness of the lenses made of spherical material may be thinner than the center thickness of the aspherical lens, so that the thickness of the sensor system can be provided slimly. By adjusting the thickness of these lenses, thermal compensation can be performed for temperatures that change from low to high temperatures.

[0165]

[0166] When describing the center spacing (CG) between adjacent lenses, the following conditions can be satisfied.

[0167] Condition 1: CT1 < CG1 Condition 2: CG2 < CG1 < CG3

[0168] Condition 3: CG4+CG5 < CG1 Condition 4: CG4 < CG5 < CG2

[0169] Condition 5: CT6 < CG3 Condition 6: CT1*3 < CG3

[0170] Condition 7: (CT1+CT2) < CT6

[0171] By providing a maximum center spacing between lenses that is greater than the maximum center thickness of the lenses, a receiving optical system can be provided in which the center spacing between spherical and aspherical lenses does not increase. Furthermore, since the maximum center spacing between lenses is provided to be three times greater than the minimum center thickness of each lens, the optical path can be controlled.

[0172]

[0173] The effective diameter (CA1-CA6) of each lens can satisfy the following conditions.

[0174] Condition 1: CA12 < CA11 < CA12*2 Condition 2: CA2 < CA1

[0175] Condition 3: CA3 < CA1 Condition 4: 0.5 < CA21 / CA22 < 1.5

[0176] Condition 5: 0.5 < CA4 / CA5 < 1.5 Condition 6: 0.5 < CA32 / CA31 < 1.5

[0177] Condition 7: 0.5 < CA41 / CA42 < 1.5 Condition 8: 0.5 < CA51 / CA52 < 1.5

[0178] Condition 9: CA5 < CA6 < CA4

[0179] The effective diameter of each of the first to sixth lenses (111-116) may be greater than the diagonal length of the effective area of ​​the sensing unit (151). The sixth lens (116) has an aspherical surface and can guide light incident through the fifth lens (115), which is a spherical lens, to the entire area of ​​the sensing unit (151).

[0180]

[0181] FIG. 7 is an example of lens data of the optical system of the embodiment of FIG. 6. As shown in FIG. 7, the radius of curvature on the optical axis (OA), the center thickness (CT) of the lenses, the center spacing (CG) between adjacent lenses, the refractive index at the d-line, the Abbe number, and the size of the effective diameter of the first to sixth lenses (111-116) can be set. As shown in FIG. 8, among the lenses of the embodiment of FIG. 6, the lens surface of the sixth lens (116) may include an aspherical surface having a radius of curvature (R), a conic constant (K), and a 16th-order aspherical surface coefficient (AG). For example, the object-side surface and the sensor-side surface of the sixth lens (116) may be lens surfaces having a 16th-order aspherical surface coefficient. The focal lengths (F1, F3) of the first and third lenses (111, 113) may have negative refractive power, and the focal lengths (F2, F4, F5, F6) of the second, fourth, fifth, and sixth lenses (112, 114, 115, 116) may have positive refractive power. The refractive powers (F1-F6) and the overall focal length (F) of each lens may satisfy the following conditions.

[0182] Condition 1: │F1│ < │F3│ Condition 2: │F3│ < F2

[0183] Condition 3: 0.5 < F4 / F5 < 1.5 Condition 4: F6 < F4

[0184] Condition 5: F <│F1│< F5 Condition 6: F*2 < │F1│

[0185] Condition 7: F < BFL

[0186] Here, the focal length of the second lens (112) is the largest among the lenses and may be greater than the focal length (F) of the entire optical system. Accordingly, the optical system may have improved MTF characteristics, aberration control characteristics, resolution characteristics, etc. within the set field of view range, and may have good optical performance in the periphery of the field of view. In addition, the composite focal length may satisfy the following conditions.

[0187] Condition 1: │F13│ < F46 (F13 < 0)

[0188] Condition 2: F46 < │F12│(F12 < 0)

[0189] Condition 3: F < F2 < F24 < │F14│(F14 < 0)

[0190] Condition 4: 0 < F45 < F24

[0191] F13 is the composite focal length of the first to third lenses, F12 is the composite focal length of the first and second lenses, F24 is the composite focal length of the second to fourth lenses, F14 is the composite focal length of the first to fourth lenses, F46 is the composite focal length of the fourth to sixth lenses, and F45 is the composite focal length of the fourth and fifth lenses.

[0192] TTL and FOV can satisfy the following conditions:

[0193] Condition 1: CA11*2 < TTL

[0194] Condition 2: F4*2 < TTL

[0195] Condition 3: 1 < TTL / FOV < 5

[0196]

[0197] Fig. 9 is a graph showing the diffraction MTF in the optical system of Fig. 6, and is a graph showing the modulation of the luminance according to the spatial frequency. That is, Fig. 9 shows the diffraction MTF at room temperature, and is a graph measuring the luminance ratio according to the position of the defocusing position. Fig. 10 is a graph showing the aberration characteristics in the optical system of Fig. 6. In the aberration graph of Fig. 10, it is a graph measuring spherical aberration (longitudinal spherical aberration), astigmatic field curves, and distortion from left to right. In Fig. 10, the X-axis can represent the focal length (mm) and the degree of distortion (%), and the Y-axis can represent the height of the image. In addition, the graph for spherical aberration is a graph for light in the wavelength bands of about 930 nm, about 940 nm, and about 950 nm, and the graph for astigmatism and distortion is a graph for light in the wavelength band of about 940 nm. In the aberration diagram of Fig. 10, 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).

[0198]

[0199] The optical system (100) according to the first and second embodiments generates chromatic aberration, and can correct the chromatic aberration using an aspherical lens. When the lens repeatedly contracts and expands as the temperature changes from low to high, since the amount of change in lens characteristics due to the temperature change is the same for lenses of the same material, 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).

[0200] 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 (dn / dt) 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. To this end, the first to fifth lenses are made of a spherical glass material, and the sixth lens is made of an aspherical glass material. The existing optical filter is arranged between the sensing unit and the last lens. The optical filter (155) of the embodiment of the invention can be arranged close to the aperture (ST), that is, between the aperture (ST) and the fifth lens (105, 115), or between the fourth and fifth lenses (114, 115). Accordingly, the angle of incidence of light incident on the optical filter (155) can be minimized. The angle of incidence (AOI) of the main beam on the incidence surface of the optical filter (155) can be inspected using AOI equipment to be less than 20 degrees, for example, 2 degrees or less, at 0 field (0F), and the angle of incidence of the main beam on the image sensor can be 50 degrees or less. Accordingly, the problem of the angle of incidence of the main beam shifting can be minimized.

[0201]

[0202] 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.

[0203] [Mathematical Formula 1] 0 < CT1 / CT2 < 3

[0204] 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 < CT1 / CT2 < 1.

[0205] [Equation 2] 3 < CA11 / CT1

[0206] 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.

[0207] [Mathematical Formula 3] 0 < CT6 / CT5 < 2

[0208] 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 deterioration of optical performance. Preferably, mathematical expression 3 can satisfy 0.5 < CT6 / CT5 < 1.5.

[0209] [Mathematical Formula 4] 0.5 < CT6 / (CT1+CT2) < 2.5

[0210] 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 0.5 < CT6 / (CT1+CT2) < 1.5. 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.

[0211] [Equation 5] 0.5 < CG3 / CT6 < 1.5

[0212] 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: 0.5 < CG3 / CT6 < 2 can be satisfied.

[0213] [Equation 6] 0 < CG5 / CG1 < 0.5

[0214] 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 spacings between the spherical lens and the aspherical lens. Preferably, 0 < CG5 / CG6 < 0.4 can be satisfied.

[0215] [Equation 6-1] 0 < CG5 / CG2 < 1

[0216] In mathematical expression 6-1, the center distance (CG2) between the second and third lenses is set to be larger than the center distance (CG5) between the fifth and sixth lenses, so that the center distance (CG2) between the two lenses located on the object side of the aperture (ST) can be set to be larger than the center distance (CG5) between the two lenses adjacent to the sensor unit (151). Accordingly, the light paths on the incident side and the output side of the aperture (ST) can be adjusted.

[0217] [Mathematical Formula 7] 1 < CG4 / OFt

[0218] In mathematical expression 7, OFt is the thickness of the optical filter (155), and may be smaller than the center spacing (CG4) between the fourth and fifth lenses. In mathematical expression 7, a space in which the optical filter (155) can be installed can be secured by the center spacing (CG4) between the fourth and fifth lenses. Preferably, 1 < CG3 / OFt < 2 can be satisfied.

[0219] [Equation 8] CG2 < CG1 < CG3

[0220] In mathematical expression 8, the center spacings (CG1, CG2, CG3) between the first to fourth lenses can be set. Accordingly, the first lens (101, 111) has a convex meniscus shape toward the object, and the third lens (103, 113) provides a concave shape on both sides, so that the spacings can be set.

[0221]

[0222] [Equation 9] 5 < TTL / CT_AVER < 25

[0223] 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.

[0224] [Equation 10] 1.70 < Nd1

[0225] 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 1.75 < Nd1 < 2.1. 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.

[0226] [Mathematical Formula 10-1] 1.70 ≤ Aver(Nd1:Nd6) < 1.80

[0227] 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.

[0228] [Equation 10-2] GM_Nd_Aver < GL_Nd_Aver

[0229] GL_Nd_Aver is the average of the refractive index values ​​at the d-line of spherical glass lenses, and GM_Nd_Aver is the average of the refractive index values ​​at the d-line of aspherical glass lenses, which are glass mold lenses. The spherical lens is a lens made of non-injection-molded glass, and the aspherical lens is a lens made of injection-molded glass. Spherical lenses with high refractive index are positioned on the object side of the aspherical lens to control chromatic dispersion.

[0230] [Equation 11] 0 < Nd1 / Nd3 < 1.5

[0231] Nd1 and Nd3 are the refractive indices of the first and third lenses at the d-line. In Equation 11, the difference in the refractive indices of the first lens and the third lens can be reduced, thereby preventing the reduction in color dispersion caused by lenses made of glass. Preferably, Equation 11 can satisfy Nd3 < Nd1.

[0232] [Equation 12] 0 < Nd3 / Nd2 < 1.5

[0233] Nd2 and Nd3 are the refractive indices of the second and third lenses at the d-line. Preferably, Equation 12 can satisfy Nd3 < Nd2. In Equation 12, by setting the refractive index of the second lens higher than the refractive index of the third lens, the reduction in color dispersion caused by lenses made of spherical materials can be prevented.

[0234] [Equation 13] (Vd4*Nd4) < (Vd3*Nd3)

[0235] Vd3 and Vd4 are the Abbe numbers of the third and fourth lenses. In Equation 13, by setting the product of the refractive index and the Abbe number of the third lens (103, 113) to be greater than the product of the refractive index and the Abbe number of the fourth lens (104, 114), the color dispersion by the lens made of a spherical material can be controlled.

[0236] [Mathematical Formula 13-1] (Vd5*Nd5) < (Vd6*Nd6)

[0237] Vd5 and Vd6 are the Abbe numbers of the fifth and sixth lenses. In Equation 13-1, by setting the product of the refractive index and the Abbe number of the sixth lens (106, 116) to be greater than the product of the refractive index and the Abbe number of the fifth lens (105, 115), the color dispersion by the spherical material lens and the color dispersion by the aspherical lens can be controlled.

[0238] [Equation 14] 2 < D1 / BFL < 6

[0239] BFL is the optical axis distance from the imaging surface of the sensing unit (151) to the center of the sensor-side surface of the last lens, i.e., the sixth lens (106, 116), and D1 is the optical axis distance from the imaging surface of the sensing unit (151) to the sensor-side surface of the optical filter (155). By satisfying mathematical expression 14, the optical filter (155) can be positioned adjacent to the aperture (ST) or positioned between lenses closer to the object side than the last lens.

[0240] [Equation 14-1] 1 < SD / D1 < 1.5

[0241] SD is the distance in the direction of the optical axis from the aperture (ST) to the imaging surface of the sensing unit (151). When mathematical expression 14-1 is satisfied, the optical filter (155) can be placed closer to the sensor side than the aperture (ST).

[0242] [Equation 14-2] 1 < BFL / CG4 < 5

[0243] When mathematical expression 14-2 is satisfied, the optical filter (155) is placed within the gap between the fourth and fifth lenses, and the optical axis distance (BFL) between the last lens and the sensing unit can be reduced.

[0244]

[0245] [Equation 15] (CT2*3) < D1 < (CT2*5)

[0246] In mathematical expression 15, the optical axis distance (D1) from the surface (i.e., the imaging surface) of the sensing unit (151) to the sensor-side surface of the optical filter (155) can be set to be three times greater than the center thickness (CT2) of the second lens (102, 112). Accordingly, the incident angle of the main beam incident on the optical filter (155) can be reduced to less than 20 degrees, and the problem of the incident angle shifting at low and high temperatures compared to room temperature can be minimized. Here, the center thickness (CT2) of the second lens can be greater than the total focal length (F). That is, F < CT2 is satisfied.

[0247] [Equation 16] 0.2 < D1 / D2 < 1

[0248] D2 is the optical axis distance from the center of the object-side surface of the first lens (101) to the object-side surface of the optical filter (155). When mathematical expression 16 is satisfied, the optical filter (155) may be placed between the lenses, or may be placed between the fourth and fifth lenses, or on the sensor-side surface of the lens adjacent to the aperture (ST). Accordingly, the incident angle of the main beam incident on the optical filter (155) can be reduced to less than 20 degrees, and the problem of the incident angle shifting at low and high temperatures compared to room temperature can be minimized. Preferably, D1 < D2 can be satisfied.

[0249] [Equation 17] 0.5 < D1 / CA_Max < 1.5

[0250] CA_Max is the maximum effective diameter between the object-side and sensor-side surfaces of the lenses. Mathematical expression 17 can set the position and maximum effective diameter of the optical filter. Preferably, Mathematical expression 17 can satisfy 0.5 < D1 / CA_Max < 1.

[0251] [Mathematical Formula 18] 1 < CA11 / CA21 < 5

[0252] 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 < CA11 / CA21 < 3 can be satisfied.

[0253] [Mathematical Formula 19] 0 < CA32 / CA41 < 2

[0254] 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.

[0255] [Mathematical Formula 20] 0.5 < CA52 / CA61 < 2

[0256] 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 that is incident on the sensing unit (151) through the fifth lens and the sixth lens. Mathematical expression 20 can preferably satisfy 0.8 < CA42 / CA51 < 1.3.

[0257] [Mathematical Formula 21] 1 < CA11 / CA62 < 5

[0258] CA11 is the effective diameter of the first surface (S1) of the first lens, and CA62 means 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, which is a spherical lens, can be increased, and the path of light toward the sensing unit can be set through the last lens, which is an aspherical lens. Mathematical expression 21 can preferably satisfy 1.5 < CA11 / CA62 < 3.

[0259] [Equation 22] 50 < TTL / Nd1

[0260] 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: 70 < TTL / Nd1 < 250 can be satisfied.

[0261] [Equation 23] 10 < CA11 / Nd1 < 60

[0262] 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: 15 < CA11 / Nd1 < 50 can be satisfied.

[0263] [Equation 24] 2 < CG_Max / CG4 < 15

[0264] CG_Max refers to the maximum center spacing between lenses within the optical system. When mathematical expression 24 is satisfied, the maximum center spacing between lenses is positioned closer to the object than the position between the fourth and fifth lenses, and can suppress an increase in the size of the sixth lens. Preferably, 2 < CG_Max / CG4 < 13 can be satisfied.

[0265] [Equation 25] 1 < CT6 / BFL < 3

[0266] 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, 1.3 < CT6 / BFL < 2.5 can be satisfied.

[0267] [Equation 26] 3 < TTL / Max_CG

[0268] In mathematical expression 26, the total optical axis length (TTL) can be set to be three times greater than the maximum center distance (Max_CG) among the center distances between the lenses. Accordingly, the maximum center distance can be set within the total optical axis length. Preferably, mathematical expression 26: 4 < TTL / Max_CG < 10 (first embodiment) or 20 < TTL / Max_CG < 35 (second embodiment) can be satisfied.

[0269] [Equation 27] 3 < TTL / Max_CT

[0270] In mathematical expression 27, the total optical axis length (TTL) can be set to be three times greater than the maximum interval (Max_CT) 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, mathematical expression 27: 4 < TTL / Max_CT < 10 (first embodiment) or 30 < TTL / Max_CT < 45 (second embodiment) can be satisfied.

[0271] [Equation 28] 2 < |L6R2| / CT6

[0272] 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, 3 < |L6R2| / CT6 < 10 can be satisfied.

[0273] [Equation 29] 1 < |L6R2| / L6R1 < 5

[0274] 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.

[0275] [Mathematical Formula 30] 10 < L1R1 / L1R2

[0276] L1R1 is the radius of curvature of the object-side surface of the first lens, and L1R2 is the radius of curvature of the sensor-side surface of the first lens. 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, 10 < L1R1 / L1R2 < 40 (first embodiment) can be satisfied, or 40 < L1R1 / L1R2 < 100 (second embodiment) can be satisfied.

[0277] [Equation 31] 0 < |L2R1 / L2R2| < 5

[0278] L2R1 is the radius of curvature of the object-side surface of the second lens, and L2R2 is the radius of curvature of the sensor-side surface of the second lens. When mathematical expression 31 is satisfied, the refractive power of the second lens (102, 112) can be controlled and the optical performance can be improved, and the effective diameters of the sensor-side lenses of the second lens (102, 112) can be adjusted. Preferably, mathematical expression 31 can satisfy 1 < |L2R1 / L2R2| < 3.5.

[0279] [Equation 32] 0 < CT_Max / CG_Max < 2

[0280] 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: 0.5 < CT_Max / CG_Max < 1.5 can be satisfied.

[0281]

[0282] [Equation 33] 0 < ΣCT / ΣCG < 2

[0283] 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.

[0284] [Equation 34] 5 < ΣNd < 15

[0285] 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.

[0286] [Equation 35] 10 < ΣVd / ΣNd < 50

[0287] 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, 15 < ΣVd / ΣNd < 25 can be satisfied.

[0288] [Equation 36] 100 < ΣCT*n < 700

[0289] 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, 200 < ΣCT*n < 300 (first embodiment) or 300 < ΣCT*n < 600 (second embodiment) can be satisfied.

[0290] [Mathematical Formula 37] 1 < CA11 / CA_Min < 3

[0291] 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 1.5 < CA11 / CA_Min < 2.5.

[0292] [Equation 38] 1 < CA_Max / CG_Max < 4

[0293] 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, 1.5 < CA_Max / CG_Max < 3.8 can be satisfied.

[0294] [Equation 39] 0.5 < CA_Max / D2 < 1.5

[0295] When mathematical expression 39 is satisfied, the optical axis distance (D2) between the object-side surface of the optical filter (155) and the first lens (101, 111) and the maximum effective diameter of the lens surfaces can be set based on this. Preferably, 0.5 < CA_Max / D2 < 1 can be satisfied.

[0296] [Equation 40] 1 < TTL / D1 < 20

[0297] In mathematical expression 40, the total optical axis length (TTL) of the optical system can be set to be more than 1 time the optical axis distance (D1) between the optical filter (155) and the sensing unit, thereby setting the position of the optical filter (155). Preferably, the first embodiment satisfies 2 < TTL / D1 < 3, and the second embodiment satisfies 10 < TTL / D1 < 18.

[0298] [Mathematical Formula 41] 1 < CA_Max / (2*ImgH) < 5

[0299] 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.

[0300] [Equation 42] 1 < TD / CA_Max < 4

[0301] 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 1.2 < TD / CA_Max < 3.

[0302] [Equation 43-1] SD < TD

[0303] The above SD is the optical axis distance from the position of the aperture to the surface of the sensing unit.

[0304] [Equation 43] 0 < F / │L6R2│ < 0.5

[0305] F is the effective focal length of the optical system, and L6S2 is the radius of curvature of the sensor-side surface of the sixth lens. When mathematical expression 43 is satisfied, the effect on optical system reduction, such as 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.

[0306] [Equation 44] 0 < F / L1R1 < 0.5

[0307] 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.

[0308] [Equation 45] 0 < EPD / │L6R2│ < 0.5

[0309] 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 < 0.3 can be satisfied.

[0310] [Equation 46] 0 < EPD / L1R1 < 0.5

[0311] 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.

[0312] [Equation 47] 1 < |F1│ / F < 5

[0313] 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, 2 < |F1│ / F < 5 can be satisfied.

[0314] [Equation 48] 0 < |F13| / F46 < 2

[0315] 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 established.

[0316] [Equation 49] 0 < |F1 / F6| < 3

[0317] 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, 0 < |F1 / F6| < 1 can be satisfied.

[0318] [Mathematical Formula 50] 0 < F4 / F5 < 2

[0319] The fourth and fifth lenses are provided as spherical lenses with positive power, which can improve aberrations, and as aspherical lenses that can effectively guide light.

[0320]

[0321] [Mathematical Formula 51] 80mm < TTL

[0322] TTL (Total track length) means 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, the first embodiment satisfies 100 mm < TTL < 200 mm, and the second embodiment can satisfy 200 mm < TTL < 500 mm.

[0323] [Mathematical Formula 52] 5mm < ImgH < 20mm

[0324] 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 7 mm < ImgH < 15 mm or 7 mm < ImgH < 11 mm.

[0325] [Mathematical Formula 53] 3mm < BFL < 20mm

[0326] In mathematical expression 53, the BFL (Back focal length) is set to exceed 3 mm, thereby securing the installation space of the cover glass (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 < 18 mm. When the BFL is less than the range of mathematical expression 53, some of the light traveling 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.

[0327] [Mathematical Formula 54] 3mm < F < 20mm

[0328] Mathematical expression 54 can set the overall focal length (F) to suit the vehicle optical system. Mathematical expression 54 can satisfy 3 mm < F < 15 mm.

[0329] [Mathematical Formula 55] 100 degrees < FOV

[0330] 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 ≤ 150 degrees can be satisfied. In mathematical expression 55, the range of the vehicle optical system can be set by the angle of view. The sensor length in the horizontal direction is based on 19 mm ± 0.7 mm. In addition, 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 three or more aspherical lenses are mixed with spherical lenses in the optical system (100), the deterioration of optical characteristics can be prevented through temperature compensation and aberration correction by the aspherical lens made of glass.

[0331] [Equation 56] 1 < TTL / Vd1

[0332] Mathematical expression 56 can provide an improved vehicle optical system by establishing a relationship between the entire optical axis length of the optical system and the Abbe number of the first lens (101, 111). Mathematical expression 56 can preferably satisfy 2 < TTL / Vd1 < 5 (first embodiment) or 5 < TTL / Vd1 < 15 (second embodiment).

[0333] [Mathematical Formula 57] 10 < TTL / ImgH

[0334] Mathematical expression 57 can set the total optical axis length (TTL) of the optical system and the diagonal length (ImgH) from the optical axis 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 10 < TTL / ImgH < 20 (first embodiment) or 30 < TTL / ImgH < 55 (second embodiment).

[0335] [Equation 58] 0 < BFL / ImgH < 3

[0336] 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). In Mathematical expression 58, the first embodiment can satisfy 1 < BFL / ImgH < 2, and the second embodiment can satisfy 0 < BFL / ImgH < 1. 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 at the center and periphery of the field of view (FOV).

[0337] [Mathematical Formula 59] 6 < TTL / BFL

[0338] 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 7 < TTL / BFL < 15 (first embodiment) or 30 < TTL / BFL < 80 (first embodiment).

[0339] [Equation 60] 0 < F / TTL < 0.5

[0340] 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.

[0341] [Equation 61] 0 < F / BFL < 2

[0342] 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.

[0343] [Equation 62] 0 < F / ImgH < 1.5

[0344] 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 0.8 < F / ImgH < 1.2 or 0.3 < F / ImgH < 0.8.

[0345] [Equation 63] 0.5 < F / EPD < 1.5

[0346] 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.

[0347] [Equation 64] 100 < TTL / F#

[0348] Mathematical expression 64 can set the F number (F#) and the overall optical axis length. Accordingly, the overall size and brightness of the optical system can be controlled. Mathematical expression 64 preferably satisfies 150 < TTL / F# < 250 (first embodiment) or 350 < TTL / F# < 650.

[0349] [Equation 65] 100 < FOV / F# < 250

[0350] 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 120 < FOV / F# < 220. Here, F# can be provided as 1.2 or less or 1 or less to provide a bright image.

[0351] [Equation 66] 100 < (CT_Max+CG_Max)*n < 300

[0352] 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).

[0353] [Equation 67] 15 < TTL / n < 80

[0354] Preferably, mathematical expression 67 can set the number of lenses (n) according to the entire optical axis length, and the first embodiment can satisfy the condition of 20 < TTL / n < 30, or the second embodiment can satisfy 40 < TTL / n < 75.

[0355] [Mathematical Formula 68] 0.1 < FOV < TTL < 1.5

[0356] 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, 0.1 < FOV < TTL < 1 can be satisfied.

[0357] [Equation 69]

[0358]

[0359] In mathematical expression 69, Z may represent Sag, which is the distance from an arbitrary position on an aspherical surface to the vertex of the aspherical surface in the direction of the optical axis. Y may represent the distance from an arbitrary position on the aspherical surface to the optical axis in the direction perpendicular to the optical axis. c may represent the curvature of the lens, and K may represent the conic constant. In addition, A, B, C, D, E, and F may represent aspheric coefficients.

[0360]

[0361] 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).

[0362] Table 1 shows the items of the mathematical formulas described above in the optical system (100) of the embodiment, including the TTL (mm), BFL (mm), effective focal length (F), ImgH (mm), sum of the center thicknesses of each lens, sum of the center spacings between adjacent lenses, TTL (mm), 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, F2, F3, F4, F5) of each of the first to fifth lenses, and composite focal length, FOV, edge thickness (ET), F number, etc. of the optical system (100). Here, the units of TTL, BFL, F, ImgH, thickness, SD, ET, focal length, etc. are mm.

[0363] Item 1 Example 2 Example F (EFL) 10.3875.018F1-38.854-16.170F283.05236.032F3-34.071-20.690F457.38032.094F563.77328.789F644.43527.611ΣNd10.43210.764ΣVd210.051230.996ΣCT84.23041.539ΣCG48.62727.972TTL145.619386.427F#0.7000.700ET 117.92008.903ET210.41304.504ET313.58608.168ET411.71585.335ET511.46964.725ET616.19778.850FOV130.000130.000 EPD14.8367.169BFL12.7635.655TD132.85769.512ImgH9.5004.549SD67.43232.487F13-18.1-10.1F4625.813.4F4530.515.6

[0364]

[0365] Table 2 shows the result values ​​for the mathematical expressions 1 to 34 described above in the optical system (100) of the embodiment. Referring to Table 2, 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).

[0366] Mathematical Formula 1 Example 2 Example 10 < CT1 / CT2 < 30.4120.45423 < CA11 / CT112.04111.06030 < CT6 / CT5 < 20.9931.07640.5 < CT6 / (CT1+CT2) < 2.51.0221.08250.5 < CG3 / CT6 < 1.50.9991.34760 < CG5 / CG1 < 0.50.0650.2667CG4 / OFt < 51.5551.5098CG2 < CG1 < CG3SatisfiedSatisfied95 < TTL / CT_AVER < 2510.37355.816101.70 < Nd11.8041.911110 < Nd1 / Nd3 <1.5 1.189 1.260 120 < Nd3 / Nd2 <1.5 0.83 90.789 13(Vd4*Nd4) < (Vd3*Nd3) Satisfied Satisfied 142 < D1 / BFL < 64.39 04.94 215(CT2*3) < D1 < (CT2*5) Satisfied Satisfied 160.5 < D1 / D2 < 1.5 Satisfied Satisfied 170.5 < D1 / CA_Max < 1.5 0.78 00.84 2181 < CA11 / CA21 < 51.5 48 1.43 4190 < CA32 / CA41 < 20.77 5 0.73 9 20 0.5 < CA52 / CA61 < 21.03 01.11 8 211 < CA11 / CA62 < 52.0862.1392250 < TTL / Nd180.720202.2312310 < CA11 / Nd1 < 6039.82417.364242 < CG_Max / CG4 < 154.4989.283251 < CT6 / BFL < 31.6381.845263 < TTL / CG_Max6.97927.579273 < TTL / CT_Max6.92339.972282 < |L6R2| / CT64.2238.297291 < |L6R2| / L6R1 < 52.1973.8673010 < L1R1 / L1R218.29876.588310 < |L2R2 / L2R1| <52.1032.600320 < CT_Max / CG_Max < 21.0080.742330 < ∑CT / ∑CG < 31.7321.485345 < ∑Nd <1510.43210.764.

[0367]

[0368] Table 3 shows the results 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).

[0369] 수학식제1실시예제2실시예3510 < ∑Vd / ∑Nd <5020.13421.46136100 < ∑CT*n < 700505.379249.236371 < CA11 / CA_Min < 32.0862.139381 < CA_Max / CG_Max < 43.4432.368390.5 < CA_Max / D2 < 1.50.8300.718401 < TTL / D1 < 32.59913.828411 < CA_Max / (2*ImgH) < 53.7811.824421 < TD / CA_Max < 41.8492.095430 < F / │L6R2│ < 0.50.1180.058440 < F / L1R1 < 0.50.0200.005450 < EPD / │L6R2│< 0.50.1680.083460 < EPD / L1R1 < 0.50.0280.007471 < |F1| / F < 53.7413.222480 < |F13| / F46 < 20.7010.751490 < |F1 / F6| < 30.8740.586500 < F4 / F5 < 20.9001.1155180 < TTL145.619386.427525 < ImgH < 209.5009.098533 < BFL < 2012.7505.635545 < F < 2010.3875.01855100 < FOV130.000130.000561 < TTL / Vd13.12710.9625710 < TTL / ImgH15.32842.476580 < BFL / ImgH < 31.3420.619596 < TTL / BFL11.42168.577600 < F / TTL < 0.50.0710.013610 < F / BFL < 20.8150.891620 < F / ImgH < 1.51.0930.552630.5 < F / EPD < 1.50.7000.70064100 < TTL / F#207.982552.04365100 < FOV / F# < 250185.673185.71666100 < (CT_Max+CG_Max)*n < 300251.397146.4646715 < TTL / n < 8024.27064.404680.1 < FOV / TTL < 1.50.8930.336.

[0370]

[0371] FIG. 11 is a block diagram of a sensor device having the optical system according to an embodiment of the invention. Referring to FIG. 11, the sensor device includes a control unit (10), a light source driving unit (20), a transmission optical system (30), a reception optical system (50) disclosed above, and a signal processing unit (60). The 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. The light source driving unit (20) supplies power to and drives a 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 may include topographic information of the driving section, traffic congestion information, weather, etc.

[0372] The wavelength of the laser beam generated from the light source may be in the range of 890 nm to 960 nm or 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. The transmitting optical system (30) transmits the laser beam generated from the light source to an object (40) through a lens unit 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 sensor converts the received light into an electrical signal using a photodiode. That is, the sensing unit is arranged in a matrix type to convert light received from an object scanned in each of the horizontal and vertical directions into current.

[0373] The signal processing unit (60) converts the output of the receiving optical system (50) into 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. The control unit (10) can receive the vehicle's 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's speed, the road condition of the road on which the vehicle is driving, and the driving environment information, and can provide sensor data including the distance to the object and the shape information of the object to the free-roaming device.

[0374] FIG. 12 is a diagram showing an example of measuring an object in a vehicle having a sensor system of the invention, and FIG. 13 is a diagram showing an example of surrounding surveillance in a vehicle having a sensor system of the invention. Referring to FIGS. 12 and 13, a vehicle (202) having a sensor system includes a transmitting optical system for projecting a laser beam (201) generated by a light source toward a target scene, and a receiving optical system for receiving light (203) reflected from the target or subject (210). The sensor system also includes a LiDAR system, which typically includes a controller for calculating distance information about the subject (210) from the reflected light, and an element capable of scanning or providing 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 LiDAR system range and FOV. 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.

[0375] 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.

[0376] 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. First to sixth lenses aligned along the optical axis from the object toward the sensing unit; and An optical filter is included between two adjacent lenses among the plurality of lenses, The sensor side of the lens placed on the object side and the object side of the lens placed on the sensor side based on the above optical filter have a convex shape on the optical axis. The object-side surface and the sensor-side surface of the above sixth lens have an aspherical shape on the optical axis, The sum of the powers of the fourth lens and the fifth lens has a positive value, An optical system, wherein the center spacing between the fourth lens and the fifth lens is the smallest among the center spacings between the first to sixth lenses.

2. An optical system in the first paragraph, wherein the optical filter is placed between the fourth lens and the fifth lens.

3. An optical system according to claim 1, wherein the first to fifth lenses are made of glass.

4. In the third paragraph, the optical system wherein the sixth lens is made of glass.

5. An optical system in which the object-side surface and the sensor-side surface of each of the first to fifth lenses in the fourth paragraph have a spherical shape on the optical axis.

6. An optical system according to any one of claims 1 to 5, wherein the first lens has negative refractive power.

7. In the 6th paragraph, the third lens has negative refractive power, An optical system in which the object-side surface and the sensor-side surface of the third lens have a concave shape on the optical axis.

8. In the sixth paragraph, the sixth lens has positive refractive power, An optical system in which the object-side surface and the sensor-side surface of the sixth lens have a convex shape on the optical axis.

9. An optical system according to any one of claims 1 to 5, wherein the center spacing between the third and fourth lenses is the largest among the center spacings between the first to sixth lenses.

10. In any one of clauses 1 to 5, the optical axis distance between the sensor side of the optical filter and the imaging surface of the sensing unit is D1, The optical axis distance from the sensor side of the sixth lens to the imaging surface of the sensing unit is BFL. Mathematical formula: Optical system satisfying 2 < D1 / BFL < 6.

11. First to sixth lenses aligned along the optical axis from the object toward the sensing unit; An optical filter positioned between two adjacent lenses among the plurality of lenses; and comprising an aperture positioned on the object side relative to the optical filter; The above optical filter is positioned on the sensor side relative to the two lenses having the largest center spacing among the above lenses, The above aperture is arranged around the two lenses having the largest center spacing among the above lenses, An optical system in which the object-side surface and the sensor-side surface of the sixth lens have an aspherical shape on the optical axis.

12. In the 11th paragraph, the optical filter is placed between the fourth lens and the fifth lens, The sensor-side surface of the fourth lens has a convex shape on the optical axis, An optical system in which the object-side surface of the fifth lens has a convex shape on the optical axis.

13. In paragraph 11, The first to sixth lenses are made of glass, The above third and fourth lenses are optical systems having a concave shape on both sides on the optical axis.

14. In any one of claims 11 to 13, the second and sixth lenses have a convex shape on both sides on the optical axis, The object-side surface and the sensor-side surface of each of the first to fifth lenses have a spherical shape on the optical axis, An optical system in which the composite focal lengths of the first to third lenses have negative values.

15. In any one of paragraphs 11 to 13, The above first lens has negative refractive power, The composite focal lengths of the fourth to sixth lenses have positive values, The above optical filter has a transmittance of 90% or more for some wavelengths within the range of 800 nm to 1000 nm, An optical system having an angle of view of 110 degrees or more.

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