Optical system, sensor system, and lidar device

Abstract

The optical system according to an embodiment of the present invention comprises a first lens and a second lens successively disposed from an object toward a light source. The first lens has an object-side surface having a convex shape on an optical axis and positive power. The second lens has a sensor-side surface having a convex shape on the optical axis. The interval between the centers of the first and second lenses is larger than the thickness of the center of each of the first and second lenses. The radius of curvature of the object-side surface of the first lens may differ from the radius of curvature of the sensor-side surface thereof.

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 an optical system for LIDAR (Light detection and ranging) and a device having the same. The present invention relates to a mobile device having a transmitting optical system and system for LIDAR.

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

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

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

[0005] The present invention provides an optical system having 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 transmission optical system, a sensor system, and a lidar device having improved thermal compensation characteristics.

[0006] An optical system according to an embodiment of the invention includes first and second lenses arranged in order from an object to a light source, wherein the first lens has a convex shape on an object-side surface on an optical axis and has positive power, the second lens has a convex shape on a sensor-side surface on an optical axis, a center spacing between the first and second lenses is greater than a center thickness of each of the first and second lenses, a radius of curvature of the object-side surface of the first lens and a radius of curvature of the sensor-side surface are different from each other, a center thickness of the first lens is CT1, a center thickness of the second lens is CT2, and a center spacing between the first and second lenses is CG1, and a mathematical equation: 0.5 < (CT1+CT2) / CG1 < 1.5 can be satisfied.

[0007] According to an embodiment of the invention, the effective diameters of the object-side surface and the sensor-side surface of the first lens are CA11 and CA12, and the effective diameters of the object-side surface and the sensor-side surface of the second lens are CA21 and CA22, and the mathematical formula: CT1 < CA12 < CA11, CT2 < CA21 < CA22 can be satisfied.

[0008] According to an embodiment of the invention, the radius of curvature of the object-side surface of the first lens is L1R1, the radius of curvature of the sensor-side surface is L1R2, and the mathematical equation: CT1 < L1R1 < |L1R2| can be satisfied. The radius of curvature of the object-side surface of the second lens is L2R1, and the radius of curvature of the sensor-side surface is L2R2, and the mathematical equation: CT2 < |L2R2| < L2R1 can be satisfied.

[0009] According to an embodiment of the invention, the center thicknesses of the first lens and the second lens may be the same. The absolute values ​​of the radius of curvature of the object-side surface of the first lens and the radius of curvature of the sensor-side surface of the second lens may be the same. The absolute values ​​of the radius of curvature of the sensor-side surface of the first lens and the radius of curvature of the object-side surface of the second lens may be the same. The first and second lenses may be made of glass. The object-side surface and the sensor-side surface of the first and second lenses may have a spherical shape.

[0010] According to an embodiment of the invention, there is provided a first lens adjacent to an object; a diffuser disposed on an object-side of the first lens; and a second lens disposed on a sensor-side of the first lens, wherein the object-side surface of the first lens has a convex shape on an optical axis, powers of the first and second lenses have the same sign, the first lens is made of glass, a center distance between the first and second lenses is greater than a center thickness of each of the first and second lenses, and the object-side surface of the first lens and the sensor-side surface of the second lens may have symmetrical shapes with respect to the center between the first and second lenses.

[0011] According to an embodiment of the invention, the object-side surface of the first lens and the sensor-side surface of the second lens may have the same absolute value of the radius of curvature.

[0012] According to an embodiment of the invention, the sensor-side surface of the first lens and the object-side surface of the second lens may have symmetrical shapes with respect to the center between the first and second lenses. The sensor-side surface of the first lens and the object-side surface of the second lens may have a convex shape or a flat shape. The focal lengths of the first and second lenses may have the same value. The refractive indices of the first and second lenses may have the same value.

[0013] According to an embodiment of the invention, the center distance between the first and second lenses is CG1, the angle of view of the optical system is FOV, and the mathematical expression: 1 < FOV / CG1 < 3 can be satisfied. Half of the diagonal length of the light source is RsH, and the optical axis distance from the center of the object-side surface of the first lens to the light source is TTL, and the mathematical expression: 1 < TTL / LsH < 10, 0 < TTL / FOV < 3 can be satisfied. The light source can generate light in the range of 890 nm to 960 nm.

[0014] According to an embodiment, it can have improved optical characteristics. The lidar transmission optical system of the invention can maximize the extraction efficiency of light emitted from the transmission optical system.

[0015] The lidar transmission optical system of the invention can have good optical properties in a low to high temperature range. Specifically, a plurality of lenses included in the transmission 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 glass mold lens and the glass lens. That is, the transmission optical system can effectively perform refractive power distribution in a low to high temperature range, and can prevent or minimize changes in optical properties in a low to high temperature range. Therefore, the optical system and sensor system according to the embodiment can maintain improved optical properties in various temperature ranges.

[0016] The lidar transmission optical system of the invention 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 have good optical performance in the periphery of the field of view.

[0017] The transmission optical system and sensor system according to the embodiment can achieve excellent optical characteristics while satisfying the set angle of view through glass lenses. This allows the optical system to provide a slimmer vehicle sensor system. Accordingly, the optical system and sensor system can be used 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.

[0018] Fig. 1 is a side cross-sectional view of a transmission optical system according to the first embodiment.

[0019] Figure 2 is a drawing illustrating the first and second lenses of Figure 1.

[0020] Fig. 3 is a table showing the lens characteristics of the transmission optical system of Fig. 1.

[0021] Fig. 4 is a side cross-sectional view of a transmission optical system according to the second embodiment.

[0022] Figure 5 is a drawing explaining the first and second lenses of Figure 4.

[0023] Fig. 6 is a table showing the lens characteristics of the transmission optical system of Fig. 4.

[0024] Fig. 7 is a block diagram showing a sensor system having the transmission optical system of Figs. 1 and 4.

[0025] FIG. 8 is a drawing showing an example of measuring an object in a vehicle having a sensor system of the invention.

[0026] Fig. 9 is a drawing showing an example of surrounding surveillance in a vehicle having a sensor system of the invention.

[0027] 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.

[0028] 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.

[0029] In the description of the invention, the "object-side surface" may mean a surface of a lens facing the object side on the optical axis or a vertex, the "sensor-side surface" may mean a surface of a lens facing the imaging surface (image sensor) on the optical axis or a vertex, and the "light source-side surface" may mean a surface of a lens facing the light source based on the optical axis. The convexity of one surface of the lens may mean a convex shape in the optical axis or a paraxial region, and the concaveness of one surface of the lens may mean a concave shape in the optical axis or a 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) on 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 is almost 0. Hereinafter, the optical axis may include the center of each lens or a very narrow region near the optical axis.

[0030]

[0031] FIG. 1 and FIG. 4 are side cross-sectional views of the transmission optical system of the lidar according to the first and second embodiments.

[0032] Referring to FIGS. 1 and 4, a transmission optical system (100A) and a sensor system having the same can be mounted inside or outside a vehicle to monitor a driver or sense external objects or lanes. The transmission optical system (100A) includes a plurality of lenses, and the material of each of the plurality of lenses can be selected from glass or plastic. The coefficient of linear expansion of the lenses is lower for glass than for plastic, and a lens made of glass can suppress changes in the focal imaging position due to temperature changes.

[0033] The transmitting optical system (100A) of the embodiment of the invention may include spherical lenses. Here, the spherical lens is a lens in which at least one or both of the object-side surface and the light source-side surface of the lens on the optical axis is spherical. As another example, the transmitting optical system (100A) may include a spherical lens made of glass and an aspherical lens made of glass, and the aspherical lens is a lens in which both the object-side surface and the light source-side surface are aspherical. The object-side surface is the output-side surface of each lens or the surface close to the object, and the light source-side surface is the incident-side surface of each lens or the surface close to the light source.

[0034] The optical system (100A) may include n lenses, and the nth lens is the last lens adjacent to the light source (126). n is an integer less than or equal to 4, for example, in the range of 2 to 4 or 2 to 3. The first lens (121, 131) closest to the object in the transmission optical system (100A) may be made of a glass lens. The first lens (121, 131) has a small amount of expansion and contraction change due to external temperature change, and its surface is not easily scratched, thereby preventing surface damage. Accordingly, the lenses adjacent to the object in the optical system (100A) may have a spherical shape on the optical axis (OA), and the second lens (122, 132) adjacent to the light source may have a spherical shape on the optical axis (OA) to control the path of the emitted light. The lenses in the optical system (100A) may be made of glass. Since the rate of contraction and expansion due to temperature changes in the above-mentioned glass material lenses is smaller than that of plastic material lenses, the phenomenon of the central axis of the lenses tilting within the lens barrel can be suppressed.

[0035]

[0036] The effective diameters of the above lenses may be the same. The effective diameter of each lens is the average value of the effective diameter of the object-side surface and the light-source-side surface of each lens. The effective diameters of the object-side surfaces of the above lenses may be different from each other. The effective diameters of the light-source-side surfaces of the above lenses may be different from each other. Among the lenses, the lens (121, 131) adjacent to the object may have an effective diameter of the object-side surface (S1) larger than the effective diameter of the light-source-side surface (S2). Among the lenses, the lens (122, 132) adjacent to the light source (126) may have an effective diameter of the object-side surface (S3) smaller than the effective diameter of the light-source-side surface (S4). Among the lenses, the lens (121, 131) adjacent to the object may be defined as a first lens or an object-side lens, and the lens (122, 132) adjacent to the light source may be defined as a second lens or a light-source-side lens. The above optical system (100A) may include a first lens (121, 131) close to the object and a second lens (122, 123) close to the light source (126).

[0037] Each of the lenses (121, 122, 131, 132) 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.

[0038]

[0039] The center thickness of the above lenses is the thickness at the optical axis (OA), and the edge thickness is the thickness in the direction of the optical axis at the end of the effective area. The center thicknesses (CT1, CT2) of the above lenses may be greater than the edge thicknesses (ET1, ET2). The center thicknesses (CT1, CT2) of the above lenses may be less than the center spacing (CG1) between adjacent lenses. In the above optical system (100A), the TTL (Total top length) may be more than 3 times, for example, more than 3 times and less than 7 times, than the LsH. The TTL (Total track length) is the distance from the center of the object-side surface (S1) of the first lens (121, 131) to the surface of the light source (126) on the optical axis (OA). The LsH is the distance from the center of the light source (126) to the diagonal end or half of the maximum diagonal length of the light source (126). Additionally, the effective diameter of each lens surface (S1-S4) within the optical system (100A) may be greater than the diagonal length of the light source (126). The lenses within the optical system (100A) may have positive (+) refractive power. Alternatively, at least one of the lenses may have negative (-) refractive power. The refractive power is the reciprocal of power.

[0040] On the optical axis (OA), the radius of curvature of the object-side surface (S1) of the first lens (121, 131) may be smaller than the absolute value of the radius of curvature of the light source-side surface (S2). On the optical axis, the radius of curvature of the light source-side surface (S4) of the second lens (122, 132) may be smaller than the absolute value of the radius of curvature of the object-side surface (S3). By controlling the refractive power, radius of curvature, effective diameter, and central thickness of each lens, the optical system (100A) can control the irradiated light to improve the resolution, prevent the deterioration of optical characteristics due to temperature change, and control the chromatic aberration characteristics. By controlling the effective diameter and thickness of the lenses, the assembling property of the optical system (100A) can be improved.

[0041]

[0042] Within the optical system (100A), the effective focal length (EFL) is provided to be less than 70 mm and the field of view (FOV) is provided to be less than 30 degrees, so that it can be provided as a standard transmission optical system in a vehicle sensor system. For example, the transmission optical system and the sensor system according to the embodiment can be applied to a sensing device for an Advanced Driving Assistance System (ADAS) installed inside or outside a vehicle. The optical system (100A) can be applied to a lidar transmission system. The optical system (100A) can have a condition of TTL / (2*LsH) of more than 1.5 times and less than 3.5 times. Accordingly, the central thickness of each lens along the optical axis (OA) can be increased and the size of the light source (126) can be reduced, so that a vehicle lens optical system can be provided. In addition, in order to be used in a vehicle camera, temperature compensation must be applied in a temperature range that serves as a temperature reliability evaluation standard for automotive electrical components, that is, -40°C to 120°C. That is, the lens must be configured so that the focus of the lens remains within the set range even when the lens expands or contracts due to changes in temperature. The total effective focal length (F) can be greater than 10 mm, for example, in the range of 10 mm < F < 70 mm, and can be configured with lenses made of glass material capable of the aforementioned temperature compensation.

[0043] The light source (126) generates a laser beam, and the wavelength of the laser beam may be in the range of 800 nm to 1000 nm, for example, 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 light source (126) may be implemented as a semiconductor diode laser based on a compound semiconductor, for example, InGaAs / GaAs, and may emit high power laser light. The light source (126) may include a single emitter and / or multiple emitters. The light source (126) generates laser light in the form of a line light source or a point light source.

[0044]

[0045] <First embodiment>

[0046] Fig. 1 is a side cross-sectional view of an optical system according to a first embodiment, and Fig. 2 is an enlarged view of a lens of Fig. 1. Fig. 3 is an example of lens data of the transmission optical system of Fig. 1. In Fig. 3, the radius of curvature of the optical axis (OA) of the first and second lenses (121, 122), the center thickness (CT) of the lenses, the center spacing (CG) between the lenses, the refractive index at the d-line, the Abbe number, and the size of the effective diameter can be represented.

[0047] Referring to FIGS. 1 to 3, the optical system (100A) may include a first lens (121) and a second lens (122) sequentially aligned from an object toward a light source along an optical axis (OA). The first and second lenses (121, 122) may be defined as a lens unit. The optical system (100A) may include a diffuser (Diffuser, 120) and may be defined as a transmission optical system or a transmission lens assembly. Laser light generated from the light source (126) may be emitted through the second lens (122) and the first lens (121) and irradiated to a subject through the diffuser (120).

[0048] The above diffuser (120) is placed on the object side of the first lens (121) and can refract light extracted through the first lens (121) toward the subject as parallel light. The diffuser (120) can be equipped with a micro lens array on the object side or the light source side, and the path of the light traveling therethrough is controlled using the micro lens array.

[0049] The power of the first lens (121) may be positive (+) or negative (-) on the optical axis (OA). The power of the first lens (121) has a positive (+) value. The first lens (121) may include a plastic material or a glass material, and may be, for example, a glass material. The first lens (121) made of a glass material can reduce changes in the center position and the radius of curvature due to temperature changes according to the surrounding environment, and can protect the output side surface of the optical system (100A). The object-side first surface (S1) of the first lens (121) with respect to the optical axis may be convex, and the light source-side second surface (S2) may be convex. The first surface (S1) and the second surface (S2) may have spherical surfaces. The first lens (121) may have a convex shape on both sides. Alternatively, the first surface (S1) may have a convex shape and the second surface (S2) may have a concave shape on the optical axis (OA). 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).

[0050] Since the first surface (S1) is convex and has a radius of curvature smaller than that of the second surface (S2), the path of the light traveling along the path can be refracted in a direction close to the optical axis (OA). When the refractive index of the first lens (121) is Nd1, the condition of 1.70 < Nd1 or 1.70 < Nd1 < 2.0 can be satisfied. Since the refractive index (Nd1) of the first lens (121) exceeds 1.70, the absolute value of the radius of curvature of the second surface (S2) of the first lens (121) can be larger than the radius of curvature of the first surface (S1), and lens manufacturing can be facilitated. If the refractive index (Nd1) of the first lens (121) is lower than the above condition, the first and fourth surfaces (S1, S4) must be formed sharply concave or convex in order to increase the refractive power of the first and second lenses (121, 122). In this case, lens manufacturing is not easy, the lens defect rate increases, and it may cause a decrease in yield.

[0051]

[0052] The second lens (122) may be arranged between the first lens (121) and the third lens (123). The power of the second lens (122) may be positive (+) or negative (-) on the optical axis (OA). The power of the second lens (122) has a positive value. The second lens (122) may include a plastic or glass material, and may be provided as a spherical lens made of glass, for example. The object-side third surface (S3) of the second lens (122) on the optical axis (OA) may be convex, and the light source-side fourth surface (S4) may be convex. The third and fourth surfaces (S3, S4) may be spherical. Alternatively, the third surface (S3) may be concave, and the fourth surface (S4) may have a convex shape. In contrast, the third surface (S3) may be convex and the fourth surface (S4) may be concave.

[0053] When the refractive index of the second lens (122) is Nd2, the condition of 1.70 < Nd2 or 1.70 < Nd2 < 2.10 can be satisfied. The refractive index (Nd2) of the second lens (122) can be the same as the refractive index of the first lens (121). In addition, the radius of curvature of the third surface (S3) of the second lens (122) can be larger than the radius of curvature of the fourth surface (S4). Since the third surface (S3) of the second lens (122) is convex and is provided equal to the absolute value of the radius of curvature of the second surface (S2), the center distance (CG1) between the first and second lenses (121, 122) can be greater than 5 mm or larger than the center thicknesses (CT1, CT2) of the first and second lenses (121, 122). Since the fourth surface (S4) of the second lens (122) is convex and has a radius of curvature smaller than the absolute value of the radius of curvature of the third surface (S3), the focus position (IMG) by the second lens (122) can be formed in the area between the first and second lenses (121, 122). The focus position (IMG) can be defined as a virtual imaging plane.

[0054] The center thickness (CT1) of the first lens (121) may be the same as the center thickness (CT2) of the second lens (122). Since the first lens (121) has a positive refractive power (F1 > 0), the first lens (121) can refract light emitted from the second surface (S2) through the first surface (S1) in the direction of the optical axis, and can suppress an increase in the distance from the light source side or the rear side lens of the first lens (121). Since the second lens (122) has a positive refractive power (F2 > 0), the second lens (122) can refract light emitted from the third surface (S3) through the fourth surface (S4) in the direction of the optical axis.

[0055]

[0056] The absolute values ​​of the radii of curvature of the first surface (S1) of the first lens (121) and the fourth surface (S4) of the second lens (122) on the optical axis (OA) may be the same. The absolute values ​​of the radii of curvature of the second surface (S2) of the first lens (121) and the third surface (S4) of the second lens (122) on the optical axis (OA) may be the same. The focal length of the first lens (121) and the focal length of the second lens (122) may be the same. The refractive indices and Abbe numbers of the first lens (121) and the second lens (122) may be the same. The center thicknesses (CT1, CT2) of the first and second lenses (121, 122) may be the same, and the edge thicknesses (ET1, ET2) of the first and second lenses (121, 122) may be the same. The first lens (121) may have a shape symmetrical to that of the second lens (122), and individual lenses may be provided with identical shapes. By arranging lenses of symmetrical shapes, the optical performance of the optical system can be improved and optical distortion and aberration can be reduced. In addition, the symmetrical lenses can reduce distortion or deformation of the optical system and improve light uniformity. In addition, the symmetrical lenses can reduce manufacturing complexity, simplify manufacturing, and facilitate optical characteristic adjustment.

[0057] The optical axis distance (D1) between the focus position (IMG) and the center of the third surface (S3) of the second lens (122) may be equal to the optical axis distance between the focus position (IMG) and the center of the second surface (S2) of the first lens (121), or may satisfy the condition of CG1 / 2 < D1.

[0058]

[0059] Referring to the specifications of each of the first and second lenses (121, 122) in FIG. 3, the effective focal length (EFL) has a positive value and is 5 mm or more, for example, in the range of 5 mm to 20 mm, and the distance from the lens surfaces (S2, S3) to the focal position (IMG), that is, the back focal length (BFL) is 5 mm or more, for example, in the range of 5 mm to 15 mm, and may be smaller than the focal length of each lens. In addition, the front focal length (FFL) of each lens has a negative value, and its absolute value may be larger than the back focal length. In addition, the diameter of the image plane at the focal position (IMG) is 3 mm or more, for example, in the range of 3 mm to 10 mm, and may be smaller than the effective diameter of the lens surfaces (S2, S3). The entrance pupil size of each lens (121, 122) is 10 mm or more, for example, in the range of 10 mm to 25 mm, and may be greater than the focal length of each lens (121, 122). Here, the entrance pupil position (EDP) of each lens has a positive value with respect to the lens surface (S1, S4) and is 10 mm or more, for example, in the range of 10 mm to 25 mm. The exit pupil (EXP) size of each lens is equal to the entrance pupil position value, and the exit pupil position (EXP) has a negative value with respect to the lens surface (S1, S4) and may be smaller than the center thickness of each lens.

[0060] The specifications of each lens are shown in Table 1 below.

[0061] Single lens specifications (mm) Single lens specifications (mm) EFL13.25 EDP position (based on S1) 17.0126 BFL9.583 EXP size 17.0126 FFL-12.903 EXP position (based on S2) -4.0209 IMG diameter 5.06 Standard wavelength 940 nm

[0062]

[0063] The center thickness (CT1, CT2), edge thickness (ET1, ET2), and center spacing (CG1) between adjacent two lenses of the first and second lenses (121, 122) may satisfy at least one of the following conditions.

[0064] Condition 1: ET1 < CT1 Condition 2: ET2 < CT2

[0065] Condition 3: (CT1+ET1) < CG1 Condition 4: (CT2+ET2) < CG1

[0066] Condition 5: CT1 < CG1 < CT1*3 Condition 6: CT2 < CG1 < CT2*3

[0067]

[0068] The distance between the first and second lenses (121, 122) may be the smallest at the center distance (CG1) and may gradually increase toward the edge. The distance (CG0) between the center of the first lens (121) and the diffuser (120) may be smaller than the edge thicknesses (ET1, ET2) of each of the first and second lenses (121, 122).

[0069] The optical axis distance between the first lens (121) and the diffuser (120) is CG0 and may be less than 5 mm. Since the diffuser (120) is spaced apart from the convex first surface (S1) of the first lens (121) by the distance, an increase in the effective length of the diffuser (120) can be suppressed. The diffuser (120) can refract the light emitted through the first lens (121) and emitted as parallel light. Since the light emitted through the first lens (121) is provided as parallel light, the radius of curvature of the first lens of the receiving optical system can be designed to be large. The output side surface of the diffuser (120) is the object side surface, the incident side surface is the light source side surface, and a micro lens array can be arranged on either surface. The transmitting optical system (100A) having the first and second lenses (121, 122) can spread the horizontal field of view (HFOV) of the receiving optical system (100) to 100 degrees or more because the object-side diffuser (120) is arranged in a one-dimensional shape.

[0070]

[0071] The effective diameter of the first surface (S1) of the first lens (121) may be larger than the effective diameter of the second surface (S2) and may be the same as the effective diameter of the fourth surface (S4) of the second lens (122). The effective diameter of the third surface (S3) of the second lens (122) may be smaller than the effective diameter of the fourth surface (S4) and may be the same as the effective diameter of the second surface (S2) of the second lens (122). The radius of curvature of the first surface (S1) of the first lens (121) may be smaller than the absolute value of the radius of curvature of the second surface (S2) and may be the same as the absolute value of the radius of curvature of the fourth surface (S4) of the second lens (122). The radius of curvature of the third surface (S3) of the second lens (122) may be greater than the radius of curvature of the fourth surface (S4), and may be equal to the absolute value of the radius of curvature of the second surface (S2) of the second lens (122). By adjusting the radius of curvature and the effective diameter of each lens, the Chief ray angle (CRA) may be minimized from the optical axis to the end of the effective area, that is, in the entire field, thereby maximizing the transmission efficiency. Here, when the CRA is large, the asymmetry of the divergence angle (Divergence Angel) with respect to the center of the light source (126) of the transmission optical system (100A) increases, which may reduce the transmission efficiency.

[0072]

[0073] In the optical system (100A), the sum of the refractive indices of the lenses in the lens unit is 3 or more, for example, in the range of 3 to 4. The sum of the Abbe numbers of each of the lenses is 100 or less, for example, in the range of 60 to 100. By adjusting the refractive indices of the lenses in the transmission optical system (100A), a decrease in transmission efficiency due to a temperature change of -45 to 120 degrees can be prevented and thermal compensation can be optimized. In addition, by adjusting the Abbe numbers of the lenses, a deviation in transmission efficiency according to a wavelength can be minimized. In addition, the center thickness of each lens can be 5 mm or more, for example, in the range of 5 mm to 10 mm, and the average of the center thicknesses can be 5 mm or more, for example, in the range of 5 mm to 10 mm. The center spacing (CG1) between the lenses on the optical axis (OA) can be smaller than the maximum of the effective diameters of each lens surface. The minimum of the effective diameters of each lens surface can be larger than the center spacing (CG1) between the lenses. An optical system having the center thickness and center spacing of each of these lenses can optimize thermal compensation while preventing degradation of optical performance for temperature changes from -45 degrees to 120 degrees.

[0074]

[0075] In the transmission optical system according to the first embodiment of the invention, the angle of view may be less than 30 degrees, for example, more than 1 degree and less than 30 degrees, or more than 5 degrees and less than 15 degrees. The F number of the optical system may be less than 5, for example, in the range of 1 to 5 or in the range of 2 to 4. The diagonal length of the light source (126) may be 8 mm or more, and may be greater than the height of the image sensor in the vertical direction. The invention may provide a vehicle lidar device for suppressing deformation due to temperature change by stacking glass lenses. In addition, since the first and second lenses (121, 122) have the same amount of power and the same focal length by the same lens shape, they may have improved MTF characteristics, aberration control characteristics, etc. in the angle of view range set in the optical system, and may have good optical performance.

[0076] The optical system may satisfy the following conditions: F, BFL, F#, FOV, TTL, and RsH. Here, F is the effective focal length of the receiving optical system, BFL is the optical axis distance from the last lens, i.e., the second lens (122), to the surface of the light source (126), F# is the F number of the optical system, TTL is the optical axis distance from the first lens (121) to the surface of the light source (126), FOV is the angle of view of the receiving optical system, and RsH is half the diagonal length of the light source. At least one or all of the following conditions may be satisfied.

[0077] Condition 1: FOV < F Condition 2: BFL < FOV < F

[0078] Condition 3: FOV < TTL < FOV*2 Condition 4: RsH < EPD

[0079] Condition 5: BFL < RsH

[0080]

[0081] <Second embodiment>

[0082] A second embodiment will be described with reference to FIGS. 4 to 6, and in the configuration and description of the second embodiment, the same configuration and description as in the first embodiment will be omitted.

[0083] Referring to FIGS. 4 to 6, the optical system (100A) may include a first lens (131) and a second lens (132). The optical system (100A) may include a diffuser (120) on the object-side surface of the first lens (131).

[0084] The first and second lenses (131, 132) are made of glass and are spherical lenses. The first and second lenses (131, 132) may have positive power values ​​and the same focal length. The first surface (S1) of the first lens (131) may be convex, and the second surface (S2) may be flat. The second surface (S2) may be a flat surface in a direction perpendicular to the optical axis (OA) from the optical axis (OA) to the edge. Alternatively, the second surface (S2) may be convex. The first surface (S1) and the second surface (S2) may be spherical. The refractive index (Nd1) of the first lens (131) may satisfy the condition of 1.70 < Nd1 or 1.70 < Nd1 < 2.0. The central thickness (CT1) of the first lens (131) may be the same as the central thickness (CT2) of the second lens (132).

[0085] The object-side third surface (S3) of the second lens (132) may be flat, and the light source-side fourth surface (S4) may be convex. The third surface (S3) may be a flat surface in a direction perpendicular to the optical axis (OA) from the optical axis (OA) to the edge. The third and fourth surfaces (S3, S4) may be spherical. When the refractive index of the second lens (132) is Nd2, the condition of 1.70 < Nd2 or 1.70 < Nd2 < 2.10 may be satisfied. The refractive index (Nd2) of the second lens (132) may be the same as the refractive index (Nd1) of the first lens (131).

[0086] The center thickness (CT1, CT2) of each of the first and second lenses (131, 132) may be greater than the edge thickness (ET1, ET2). The center thicknesses (CT1, CT2) of the first and second lenses (131, 132) may be the same, and the edge thicknesses (ET1, ET2) of the first and second lenses (131, 132) may be the same. The radius of curvature of the first surface (S1) of the first lens (131) may be smaller than the radius of curvature of the second surface (S2). The radius of curvature of the third surface (S3) of the second lens (132) may be greater than the radius of curvature of the fourth surface (S4). The absolute values ​​of the radii of curvature of the first surface (S1) and the fourth surface (S4) may be the same.

[0087] The center thicknesses (CT1, CT2) of the first and second lenses (131, 132) may be smaller than the center spacing (CG1) between adjacent lenses. The center spacing (CG1) between the first and second lenses (131, 132) may be greater than 5 mm, for example, in the range of 5 mm to 20 mm. The focal lengths of the first and second lenses (131, 132) may have positive values ​​and may be the same. The refractive index and Abbe number of the first lens (131) and the second lens (132) may be the same. The first lens (131) may have a shape symmetrical to that of the second lens (132), and individual lenses may be provided with the same shape. By arranging lenses of a symmetrical shape, the optical performance of the optical system can be improved and optical distortion and aberration can be reduced. In addition, the lenses of a symmetrical shape can reduce distortion or deformation of the optical system and improve light uniformity. Additionally, lenses with symmetrical shapes can reduce manufacturing complexity, simplify manufacturing, and facilitate adjustment of optical properties.

[0088] The optical axis distance between the focus position (IMG) and the center of the third surface (S3) of the second lens (132) may be equal to or greater than the optical axis distance between the focus position (IMG) and the center of the second surface (S2) of the first lens (131).

[0089]

[0090] Referring to FIG. 6, the specifications of each of the first and second lenses (131, 132) will be described. The effective focal length (EFL) has a positive value and is 5 mm or more, for example, in the range of 5 mm to 20 mm, and the distance from the lens surfaces (S2, S3) to the focal position (IMG), that is, the back focal length (BFL), is 5 mm or more, for example, in the range of 5 mm to 15 mm, and may be smaller than the focal length of each lens. In addition, the front focal length (FFL) of each lens has a negative value, and its absolute value may be larger than the back focal length. In addition, the diameter of the image formation surface at the focal position (IMG) is 3 mm or more, for example, in the range of 3 mm to 10 mm, and may be smaller than the effective diameter of the lens surfaces (S2, S3). The entrance pupil size of each of the lenses (131, 132) is 10 mm or more, for example, in the range of 10 mm to 25 mm, and may be greater than the focal length of each of the lenses (131, 132). Here, the entrance pupil position (EDP) of each lens has a zero value with respect to the lens surface (S1, S4), the exit pupil size of each lens has a positive value, and the exit pupil position (EXP) has a negative value with respect to the lens surface (S1, S4), and may be smaller than the center thickness of each of the lenses.

[0091] The specifications of each lens are shown in Table 2 below.

[0092] Single lens specifications (mm) Single lens specifications (mm) EFL11.3534 EDP position (based on S1) 16.8046 BFL7.4371 EXP size 0 FFL-11.3534 EXP position (based on S2) 16.8046 IMG diameter 5.26 standard wavelength -3.9162

[0093] The center thickness (CT1, CT2), edge thickness (ET1, ET2), and center spacing (CG1) between adjacent two lenses of the first and second lenses (131, 132) may satisfy at least one of the following conditions.

[0094] Condition 1: ET1 < CT1 Condition 2: ET2 < CT2

[0095] Condition 3: (CT1+ET1) < CG1 Condition 4: (CT2+ET2) < CG1

[0096] Condition 5: CT1 < CG1 < CT1*2 Condition 6: CT2 < CG1 < CT2*2

[0097]

[0098] The distance between the first and second lenses (131, 132) may be the smallest at the center distance (CG1) and may gradually increase toward the edge. The distance (CG0) between the center of the first lens (131) and the diffuser (120) may be smaller than the edge thicknesses (ET1, ET2) of each of the first and second lenses (131, 132). The optical axis distance between the first lens (131) and the diffuser (120) is CG0 and may be less than 5 mm. Since the diffuser (120) is spaced apart from the convex first surface (S1) of the first lens (131) by the distance, an increase in the effective length of the diffuser (120) can be suppressed. The diffuser (120) can refract light emitted through the first lens (131) and emitted as parallel light. Since the light emitted through the first lens (131) is provided as parallel light, the radius of curvature of the first lens of the receiving optical system can be designed to be large.

[0099]

[0100] The effective diameter of the first surface (S1) of the first lens (131) may be larger than the effective diameter of the second surface (S2) and may be the same as the effective diameter of the fourth surface (S4) of the second lens (132). The effective diameter of the third surface (S3) of the second lens (122) may be smaller than the effective diameter of the fourth surface (S4) and may be the same as the effective diameter of the second surface (S2) of the second lens (132). The radius of curvature of the first surface (S1) of the first lens (131) may be smaller than the radius of curvature of the second surface (S2) and may be the same as the radius of curvature of the fourth surface (S4) of the second lens (132). The radius of curvature of the third surface (S3) of the second lens (132) may be greater than the radius of curvature of the fourth surface (S4), and may be the same as the radius of curvature of the second surface (S2) of the second lens (132).

[0101]

[0102] In the optical system (100A), the sum of the refractive indices of the lenses in the lens unit is 3 or more, for example, in the range of 3 to 4. The sum of the Abbe numbers of each of the lenses is 100 or less, for example, in the range of 60 to 100. By adjusting the refractive indices of the lenses in the transmission optical system (100A), a decrease in transmission efficiency due to a temperature change of -45 to 120 degrees can be prevented and thermal compensation can be optimized. In addition, by adjusting the Abbe numbers of the lenses, a deviation in transmission efficiency according to a wavelength can be minimized. In addition, the center thickness of each lens can be 5 mm or more, for example, in the range of 5 mm to 10 mm, and the average of the center thicknesses can be 5 mm or more, for example, in the range of 5 mm to 10 mm. The center spacing (CG1) between the lenses on the optical axis (OA) can be smaller than the maximum of the effective diameters of each lens surface. The minimum of the effective diameters of each lens surface can be larger than the center spacing (CG1) between the lenses. An optical system having the center thickness and center spacing of each of these lenses can optimize thermal compensation while preventing degradation of optical performance for temperature changes from -45 degrees to 120 degrees.

[0103]

[0104] In the transmission optical system according to the second embodiment of the invention, the angle of view may be less than 30 degrees, for example, more than 1 degree and less than 30 degrees, or more than 5 degrees and less than 15 degrees. The F number of the optical system may be less than 5, for example, in the range of 1 to 5 or in the range of 2 to 4. The diagonal length of the light source (126) may be 8 mm or more, and may be greater than the height of the image sensor in the vertical direction. The invention may provide a vehicle lidar device for suppressing deformation due to temperature change by stacking glass lenses. In addition, since the first and second lenses (131, 132) have the same amount of power and the same focal length by the same lens shape, they may have improved MTF characteristics, aberration control characteristics, etc. in the angle of view range set in the optical system, and may have good optical performance.

[0105]

[0106] The optical system can satisfy the following conditions: F, BFL, F#, FOV, TTL and RsH. At least one or all of the following conditions can be satisfied.

[0107] Condition 1: FOV < F Condition 2: BFL < FOV < F

[0108] Condition 3: FOV < TTL < FOV*2 Condition 4: RsH < EPD

[0109] Condition 5: BFL < RsH

[0110] Since the first and second embodiments are optical systems applied to a lidar device, all lenses can be provided with glass. This is because glass has the advantage of being scratch-resistant and insensitive to external temperatures compared to plastic materials. To more effectively prevent scratches caused by foreign substances or when placed inside a vehicle, a glass lens is used as the first lens (121, 131), and the object-side surface of the first lens (121, 131) can have a convex shape to prevent the accumulation of foreign substances. The lidar device can detect the distance to an object, direction, speed, temperature, material distribution, and concentration characteristics while the vehicle is operating.

[0111] The optical system (100A) according to the first and second embodiments 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 the emitted light toward the lenses. Hereinafter, the optical system according to the embodiment will be described in detail. The transmission optical system according to the first and second embodiments can prevent the degradation of optical performance from low to high temperatures by considering the characteristics of the optical system for a vehicle. The optical system (100A) 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 (100A) according to the embodiment can have improved optical characteristics. For example, when the optical system (100A) satisfies at least one mathematical equation, the optical system (100A) 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). In addition, the optical system (100A) may have improved resolution. In addition, the thickness of the lens along the optical axis (OA) and the spacing between adjacent lenses along the optical axis (OA) described in the mathematical formulas may refer to the embodiments disclosed above.

[0112] [Mathematical Formula 1] 0 < CT1 / CG1 < 1

[0113] CT1 is the central thickness of the first lens, and CT2 is the central thickness of the second lens. In mathematical expression 1, by setting the central thickness (CT1) of the first lens (121, 131) and the central gap (CG1) between the first and second lenses, the rigidity of the first lens (121, 131) can be prevented from decreasing, and factors affecting aberration can be controlled. In addition, by providing the first and second lenses as glass lenses with the above thickness, heat resistance can be improved. Preferably, mathematical expression 1 can satisfy 0.2 < CT1 / CG1 < 0.8.

[0114] [Equation 2] 0 < CT2 / CG1 < 1

[0115] In mathematical expression 2, the central thickness (CT2) of the second lens (122, 132) and the central gap (CG1) between the first and second lenses are set, and the heat resistance of the second lens (122, 132) can be improved. Preferably, mathematical expression 1 can satisfy 0.2 < CT2 / CG1 < 0.8.

[0116] [Equation 3] 0.5 < (CT1+CT2) / CG1 < 1.5

[0117] In mathematical expression 3, the sum of the central thicknesses of the first and second lenses is set to be smaller than the central gap (CG1) between the first and second lenses, thereby optimizing thermal compensation according to temperature changes from low to high temperatures and preventing deterioration of optical performance. Preferably, the first embodiment satisfies (CT1+CT2) > CG1, and the second embodiment satisfies (CT1+CT2) < CG1.

[0118] [Mathematical Formula 4] CT1 < L1R1 < |L1R2|

[0119] L1R1 is the radius of curvature of the object-side surface of the first lens (121, 131), and L1R2 is the radius of curvature of the sensor-side surface of the first lens (121, 131). When mathematical expression 4 is satisfied, the first lens (121, 131) can refract the incident light in the direction of the optical axis.

[0120] [Mathematical Formula 5] CT2 < |L2R2| < L2R1

[0121] L2R1 is the radius of curvature of the object-side surface of the second lens (122, 132), and L2R2 is the radius of curvature of the sensor-side surface of the second lens (122, 132). When mathematical expression 5 is satisfied, the second lens (122, 132) can refract the incident light in the direction of the optical axis. The focus position of the light refracted through the second lens (122, 132) can be formed in the area between the first and second lenses.

[0122] [Equation 6] CT1 < CA12 < CA11

[0123] CA11 and CA12 are the effective diameters of the object-side and sensor-side surfaces of the first lens (121, 131). By providing the effective diameter of the object-side surface of the first lens (121, 131) to be larger than the effective diameter of the sensor-side surface, the path of the light traveling to the diffuser (120) can be controlled. In addition, when mathematical expression 6 is satisfied, the optical system (100A) can control the emitted light and set factors affecting aberration.

[0124] [Mathematical Formula 7] CA12 < CA22

[0125] CA22 is the effective diameter of the sensor-side surface of the second lens (122, 132). By providing the effective diameter of the sensor-side surface of the second lens (122, 132) to be larger than the effective diameter of the sensor-side surface of the first lens (121, 131), the center distance (CG1) between the first and second lenses can be adjusted.

[0126] [Equation 8] CT2 < CA21 < CA22

[0127] CA21 and CA22 are the effective diameters of the object-side and sensor-side surfaces of the second lens (122, 132). By providing the effective diameter of the sensor-side surface of the second lens (122, 132) to be larger than the effective diameter of the object-side surface, the gap between the first and second lenses can be adjusted, and the increase in the effective diameter of the first lens can be suppressed. In addition, when mathematical expression 8 is satisfied, the optical system (100A) can control the emitted light and set the factors affecting aberration.

[0128] [Mathematical Formula 9] CT1 < CG1 < CT1*3

[0129] In mathematical expression 9, the center distance (CG1) between the first and second lenses is set to be greater than the center thickness (CT1) of the first lens, thereby reducing distortion according to the shape of the first and second lenses. In addition, CT2 < CG1 < CT2*3 can be satisfied.

[0130] [Equation 10] 1.70 < Nd1

[0131] Nd1 is the refractive index at the d-line of the first lens (121, 131). In Equation 10, by setting the refractive index of the first lens (121, 131) 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 < 2.0. If it is designed to be lower than the lower limit of Equation 10, the performance of reducing the 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 (121) is designed to be lower than the lower limit of mathematical expression 10, the radius of curvature of the first and second lenses may be increased to increase the refractive power of the first and second lenses.

[0132] [Equation 10-1] 1.70 < Aver(Nd1:Nd2) < 1.9

[0133] Aver(Nd1:Nd2) is the average of the refractive index values ​​at the d-line of the first and second lenses. When mathematical expression 10-1 is satisfied, the optical system (100A) can suppress the influence of TTL.

[0134] [Equation 10-2] 1.70 < Nd2

[0135] Nd2 is the average of the refractive index values ​​at the d-line of the second lens.

[0136]

[0137] [Mathematical Formula 11] 0.5 < (Vd1*Nd1) / (Vd2*Nd2) < 1.5

[0138] Vd1 and Vd2 are the Abbe numbers of the first and second lenses. If Equation 11 is satisfied, the chromatic dispersion caused by spherical material lenses can be controlled. Equation 11 can further satisfy 0.5 < (Vd2*Nd2) / (Vd1*Nd1) < 1.5.

[0139] [Equation 12] 0.5 < (F / F1) / (F / F2) < 1.5

[0140] F1 and F2 are the focal lengths of the first and second lenses. If Equation 12 is satisfied, an optical system with a small angle of view can be provided by adjusting the focal lengths of each lens.

[0141] [Equation 13] 0.5 < F1 / F2 < 1.5

[0142] If the optical system satisfies Equation 13, an optical system with a small angle of view can be provided by adjusting the focal length of each lens. Furthermore, Equation 13 can further satisfy 0.5 < F2 / F1 < 1.5.

[0143] [Equation 14] 1 < F1 / CT1 < 3

[0144] When mathematical expression 14 is satisfied, the optical system can adjust TTL by setting the central thickness and focal length of the first glass lens. Preferably, 1.3 < F1 / CT1 < 2 can be satisfied.

[0145] [Equation 15] 1 < F2 / CT2 < 3

[0146] When mathematical expression 15 is satisfied, the optical system can adjust TTL by setting the central thickness and focal length of the second glass lens. Preferably, 1.3 < F2 / CT2 < 2 can be satisfied.

[0147] [Equation 16] 0.5 < ΣCG / ∑CT < 1.5

[0148] Where G is the sum of the center spacings between adjacent lenses, and T is the sum of the center thicknesses of each lens. When mathematical expression 16 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. Preferably, 0.7 < ΣCG / ΣCT < 1.2 can be satisfied. The first embodiment satisfies the condition: ΣCT < ΣCG, and the second embodiment satisfies ΣCG < ΣCT.

[0149] [Mathematical Formula 17] 0.5 < CA11 / CA21 < 1.5

[0150] When mathematical expression 18 is satisfied, the optical system (100A) can control the light being emitted and set factors affecting aberration, and preferably, CA11 > CA21 can be satisfied.

[0151]

[0152] [Mathematical Formula 18] 0.5 < (ΣCT*n) / F < 1.5

[0153] In Equation 18, n represents the total number of lenses in the optical system. Furthermore, n represents the number of lenses having identical or symmetrical shapes. When Equation 18 is satisfied, the optical system can exhibit good optical performance at a focal length and a set angle of view. Preferably, 0.7 < (ΣCT*n) / F < 1.2 can be satisfied.

[0154] [Mathematical Formula 19] FOV < (CT1*CT2)

[0155] In mathematical expression 19, the optical system can set the central thickness of the first and second lenses made of glass within the set angle of view.

[0156] [Mathematical Formula 20] 1 < FOV / CG1 < 3

[0157] In mathematical expression 20, the optical system can set the center spacing between the first and second lenses made of glass within a set angle of view. Preferably, 1 < FOV / CG1 < 2.5 can be satisfied.

[0158] [Equation 21] 1 < CT1 / ET1 < 5

[0159] In mathematical expression 21, by setting the center thickness (CT1) and edge thickness (ET1) of the first lens, the shape and focal length of the first lens can be adjusted, thereby suppressing an increase in TTL. Preferably, 1.5 < CT1 / ET1 < 3 can be satisfied.

[0160] [Equation 22] 1 < CT2 / ET2 < 5

[0161] In mathematical expression 22, by setting the center thickness (CT2) and edge thickness (ET2) of the second lens, the shape and focal length of the second lens can be adjusted to suppress the increase in TTL. Preferably, 1.5 < CT2 / ET2 < 3 can be satisfied.

[0162]

[0163] [Equation 23] Po1 * Po2 > 0

[0164] Po1 and Po2 represent the powers of the first and second lenses. When mathematical expression 23 is satisfied, the performance of an optical system having symmetrical lenses can be improved and a narrow angle of view can be set.

[0165] [Equation 24] 5 < TTL / Nd1 < 50

[0166] TTL is the optical axis distance from the first lens to the light source. If mathematical expression 24 is satisfied, the size and narrow angle of view of the optical system can be set. Preferably, 10 < TTL / Nd1 < 25 can be satisfied.

[0167] [Equation 25] 0 < F / L1R1 < 2

[0168] In mathematical expression 25, 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 output light and TTL. Mathematical expression 25 can preferably satisfy 0 < F / L1R1 < 0.5.

[0169] [Mathematical Formula 26] 20mm < TTL < 40mm

[0170] In mathematical expression 26, a vehicle optical system can be provided by setting the TTL to be less than 40 mm. Mathematical expression 26 can satisfy 25 mm < TTL < 36 mm. In addition, the number of lenses in the transmitting optical system can be smaller than the number of lenses in the receiving optical system. In addition, the number of aspherical lenses in the transmitting optical system can be smaller than the number of aspherical lenses in the receiving optical system.

[0171] [Mathematical Formula 27] 2mm < LsH < 10mm

[0172] LsH is half the diagonal length of the light source. Mathematical expression 52 can set the diagonal length of the light source (126) and provide an optical system having a vehicle sensor size. Mathematical expression 27 can preferably satisfy 3 mm < LsH < 8 mm.

[0173] [Mathematical Formula 28] 1mm < BFL < 7mm

[0174] In mathematical expression 28, the BFL (Back focal length) is set to less than 7 mm, thereby improving the assemblability of components and improving the joint reliability through the gap between the light source (126) and the last lens. Mathematical expression 28 can preferably satisfy 1.5 mm < BFL < 5.5 mm. If the BFL is less than the range of mathematical expression 28, some of the light emitted from the light source may not be emitted, which may cause a decrease in resolution. If the BFL exceeds the range of mathematical expression 28, stray light may be emitted, which may deteriorate the aberration characteristics of the optical system.

[0175] [Mathematical Formula 29] 10mm < F < 70mm

[0176] Mathematical expression 29 can set the effective focal length (F) of the optical system to suit the vehicle transmitting optical system. Mathematical expression 29 can satisfy 20 mm < F < 50 mm, and can be greater than the total focal length of the receiving optical system.

[0177] [Mathematical Formula 30] 1 degree < FOV < 30 degrees

[0178] In mathematical expression 30, FOV (Field of view) refers to the angle of view (Degree) of the optical system (100A), and a vehicle optical system having an angle of view (F0V) of less than 30 degrees can be provided. Preferably, 5 degrees ≤ FOV ≤ 15 degrees can be satisfied. The angle of view of the transmitting optical system can be provided narrower than the angle of view of the receiving optical system. That is, even if the angle of view of the receiving optical system is implemented wide by the diffuser (120), the sensitivity of the detection unit can be prevented from decreasing.

[0179] In mathematical expression 30, the range of the vehicle transmission optical system can be set by the angle of view. If mathematical expression 30 is satisfied, the rate of change in the effective focal length and the rate of change in the angle of view can be set low when the temperature changes from room temperature to high temperature. In addition, by mixing and using symmetrical spherical lenses within the optical system (100A), the deterioration of optical characteristics can be prevented through temperature compensation and aberration correction.

[0180] [Equation 31] 1 < TTL / CA_Max < 4

[0181] In mathematical expression 31, CA_Max refers to the largest effective diameter (mm) among the object-side and light-source-side surfaces of the plurality of lenses. Mathematical expression 31 sets the relationship between the total optical axis length of the optical system and the maximum effective diameter, thereby allowing the size of the vehicle optical system to be adjusted. Mathematical expression 31 preferably satisfies 1.3 < TTL / CA_Max < 2.3.

[0182] [Equation 32] 1 < TTL / LsH < 15

[0183] Mathematical expression 32 can set the total optical axis length (TTL) of the optical system and the diagonal length (LsH) from the optical axis of the light source (126). When the optical system (100A) according to the embodiment satisfies Mathematical expression 32, the optical system (100A) can have a TTL for application to the vehicle light source (126). Mathematical expression 32 can preferably satisfy 3 < TTL / LsH < 13.

[0184] [Equation 33] 0 < BFL / LsH < 3

[0185] Mathematical expression 33 can set the optical axis distance between the light source (126) and the last lens and the diagonal length from the optical axis of the light source (126). When the optical system (100A) according to the embodiment satisfies Mathematical expression 33, the optical system (100A) can secure BFL for applying the size of the vehicle light source (126), can set the distance between the last lens and the light source (126), and can have good optical characteristics in a narrow field of view (FOV). Mathematical expression 33 can preferably satisfy 0 < BFL / LsH < 1.

[0186]

[0187] [Equation 34] 1 < TTL / BFL < 15

[0188] Mathematical expression 34 can set the total optical axis length (TTL) of the optical system and the optical axis spacing (BFL) between the light source (126) and the last lens. When the optical system (100A) according to the embodiment satisfies Mathematical expression 34, the optical system (100A) can secure BFL. Mathematical expression 34 can preferably satisfy 4 < TTL / BFL < 13.

[0189] [Equation 35] 0.5 < F / TTL < 2

[0190] Mathematical expression 35 can set the overall focal length (F) and overall optical axis length (TTL) of the optical system (100A). Accordingly, an optical system for a driver assistance system can be provided. Mathematical expression 35 can preferably satisfy 1 ≤ F / TTL < 1.5. When the optical system (100A) according to the embodiment satisfies Mathematical expression 35, the optical system (100A) can have an appropriate focal length in the set TTL range, and provides an optical system that can form an image while maintaining an appropriate focal length even when the temperature changes from low to high. When the upper limit of Mathematical expression 35 is exceeded, the refractive power of the lenses needs to be increased, making it difficult to correct spherical aberration or distortion aberration, and when the lower limit of Mathematical expression 35 is less than the lower limit of Mathematical expression 35, the effective diameter or TTL of the lenses becomes long, which may cause a problem of the optical system becoming large.

[0191] [Equation 36] 4 < F / BFL < 20

[0192] Mathematical expression 36 can set the effective focal length (F) of the optical system (100A) and the optical axis distance (BFL) between the light source (126) and the last lens. When the optical system (100A) according to the embodiment satisfies Mathematical expression 36, the optical system (100A) 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 (100A) can minimize the distance between the last lens and the light source (126), and thus can have good optical characteristics in the angle of view (FOV). Mathematical expression 36 can preferably satisfy 5 < F / BFL < 15.

[0193] [Equation 37] 2 < F / LsH < 7

[0194] Mathematical expression 37 can set the overall focal length (F) of the optical system (100A) and the diagonal length (LsH) from the optical axis of the light source (126). This optical system (100A) can have improved aberration characteristics in the size of the vehicle light source (126). Mathematical expression 37 can preferably satisfy 4 < F / LsH < 7.

[0195] [Equation 38] 1 < F / EPD < 10

[0196] Mathematical expression 38 can set the overall focal length (F) and entrance pupil (EPD) size of the optical system (100A). Accordingly, the overall brightness of the optical system can be controlled. In other words, an optical system with a small F number can be provided. Mathematical expression 38 can satisfy 1 < F / EPD < 5.

[0197] [Equation 39] 0 < EPD / |L2R2| < 1.5

[0198] Mathematical expression 39 can set the entrance pupil diameter (EPD) and the radius of curvature of the sensor-side surface of the second lens. Accordingly, the overall size and brightness of the optical system can be controlled. Mathematical expression 64 preferably satisfies 0.5 < EPD / |L2R2| < 1.2.

[0199] [Equation 40] 0 < EPD / L1R1 < 1

[0200] Mathematical expression 40 can set the entrance pupil diameter (EPD) and the radius of curvature of the object-side surface of the first lens. Accordingly, the overall size and brightness of the optical system can be controlled. Mathematical expression 40 preferably satisfies 0 < EPD / L1R1 < 0.5.

[0201]

[0202] [Mathematical Formula 41] 0 < TTL / FOV < 3

[0203] In mathematical expression 41, a narrow angle of view can be set according to the total optical axis length (TTL). Mathematical expression 41 can satisfy 1 < TTL / FOV < 2.

[0204] [Mathematical Formula 42] 2 < FOV / F# < 10

[0205] In mathematical expression 42, the relationship between the angle of view and the F number (F#) of the optical system can be established. Mathematical expression 42 can satisfy 5 < FOV / F# < 10.

[0206] [Equation 43] 5 < TD / n < 20

[0207] TD is the optical axis distance between the first lens and the second lens. That is, 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 second lens. Therefore, if the optical system satisfies mathematical expression 43, the maximum separation distance of the lenses according to the total number of lenses (n) can be set. Preferably, 10 < TD / n < 16 can be satisfied.

[0208] [Mathematical Formula 44] 200 < (FOV*TTL) / n < 500

[0209] [Mathematical Formula 45] (TTL / n) < FOV

[0210] [Equation 46] 1 < (TD / CA_Max) *n < 10

[0211] In mathematical expressions 44 to 46, the TTL, TD, maximum effective diameter of the lens surface (CA_Max), and angle of view can be set according to the number of lenses in the optical system.

[0212] [Equation 47] (BFL*2) < CG1 < (BFL*7)

[0213] In Equation 47, the center distance (CG1) between the first and second lenses can set the optical axis distance between the last lens and the light source. If Equation 47 is satisfied, the increase in the overall TTL of the optical system can be suppressed.

[0214] [Equation 48] CGO < BFL < CT_Aver

[0215] CG0 is the optical axis distance between the diffuser and the first lens, and CT_Aver is the average of the central thicknesses of the first and second lenses. When mathematical expression 48 is satisfied, the increase in the overall TTL of the optical system can be suppressed, and the size of the optical system can be controlled.

[0216] The optical system can set the relationship between the central thickness of the lenses, the effective diameter, the field of view, the time-to-live (TTL), the optical distance (TD) of the lenses, and the refractive index of the lenses, depending on the total number of lenses. Accordingly, the chromatic aberration, resolution, size, etc. of an optical system with four or fewer lenses can be controlled.

[0217]

[0218] The optical system (100A) according to the embodiment can satisfy at least one or two or more mathematical expressions from mathematical expressions 1 to 48. In this case, the optical system (100A) can have improved optical characteristics. Specifically, when the optical system (100A) satisfies at least one or all of mathematical expressions 1 to 48, the optical system (100A) can have improved resolution and improve aberration and distortion characteristics. In addition, the optical system (100A) can secure a BFL (Back focal length) for applying a vehicle light source (126), can compensate for optical characteristic degradation due to temperature change, and can minimize the gap between the last lens and the light source (126), thereby having good optical performance within the field of view (FOV).

[0219] Table 3 shows the items of the mathematical formulas described above in the optical system (100A) of the embodiment, including the TTL (mm), BFL (mm), effective focal length (F), LsH, effective diameter, 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 fourth surface (S4), angle of view (FOV), edge thickness (ET), F number, etc. of the optical system (100A).

[0220] Item Example 1 Example 2 Item Example 1 Example 2 F34.75929.603ET13.2383.154F113.2511.35ET23.2383.154F213.2511.35TTL30.92029.120ΣNd3.6123.612F-number2.902.47ΣVd81.46981.469FOV2020ΣCT14.0014.00EPD12.00012.00ΣCG14.12010.520BFL2.804.60ΣET3.2383.154TD28.12024.5200LsH6.0006.000

[0221] Tables 4 and 5 show the results for the mathematical formulas described above in the optical system (100A) of the embodiment.

[0222] Mathematical Formula Example 1 Example 2 10 < CT1 / CG1 < 10.496 0.665 20 < CT2 / CG1 < 10.496 0.665 3 0.5 < (CT1+CT2) / CG1 < 1.5 0.99 2 1.33 14 CT1 < L1R1 < |L1R2| Satisfied Satisfied 5 CT2 < |L2R2| < L2R1 Satisfied Satisfied 6CT1 < CA12 < CA11 Satisfied Satisfied 7CA12 < CA22 Satisfied Satisfied 8CT2 < CA21 < CA22 Satisfied Satisfied 9CT1 < CG1 < CT1*3 Satisfied Satisfied 101.70 < Nd1 1.80 61.80 6110.5 < (Vd1*Nd1) / (Vd2*Nd2) <1.5 Satisfied Satisfied 120.5 < (F / F1) / (F / F2) < 1.5 Satisfied Satisfied 130.5 < F1 / F2 < 1.5 Satisfied Satisfied 141 < F1 / CT1 < 31.89 31.62 2151 < F2 / CT2 < 31.89 31.62 2160.5 < ∑CG / ∑CT < 1.5 1.00 90.75 1170.5 < CA11 / CA21 < 1.51.1081.296180.5 < (∑CT*n) / F < 1.50.8060.94619FOV < (CT1*CT2)SatisfiedSatisfied201 < FOV / CG1 < 31.4161.901211 < CT1 / ET1 < 52.1622.219221 < CT2 / ET2 < 52.1622.21923Po1 * Po2 > 0SatisfiedSatisfied245 < TTL / Nd1 < 5017.12016.123

[0223] Mathematical FormulaExample 1Example 2250 < F / L1R1 < 20.2600.2762620 < TTL < 4030.92029.120272 < LsH < 106.0006.000281 < BFL < 72.8004.6002910 < F < 7034.75929.603301 < FOV < 3020.00020.000311 < TTL / CA_Max < 41.8661.905321 < TTL / LsH < 105.1534.853330 < BFL / LsH < 20.4670.767341 < TTL / BFL < 1511.0436.330350.5 < F / TTL < 21.1241.017364 < F / BFL < 2012.4146.435372 < F / LsH < 75.7934.934381 < F / EPD < 102.8972.467390 < EPD / |L2R2|< 1.51.0761.342400 < EPD / L1R1 < 10.1090.109410 < TTL / FOV < 31.5461.456422 < FOV / F# < 106.9058.107435 < TD / n < 2014.06012.26044200 < (FOV*TTL) / n < 500309.20291.2045(TTL / n) < FOV Satisfied Satisfied 461 < (TD / CA_Max) *n < 103.3943.20847(BFL*2) < CG1 < (BFL*7) Satisfied Satisfied 48CGO < BFL < CT_Aver Satisfied Satisfied

[0224]

[0225] FIG. 7 is a block diagram of a sensor system having a transmitting optical system according to an embodiment of the invention. Referring to FIG. 7, the sensor device includes a control unit (10), a light source driving unit (20), a transmitting optical system (30), a receiving optical system (50) disclosed above, and a signal processing unit (60). 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 transmitting optical system (30). The light source generates laser light 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.

[0226] The wavelength of the laser light generated from the light source may be in the range of 800 nm to 1000 nm, for example, in the range of 890 nm to 960 nm or in the range of 940 nm ± 10 nm. The laser light source may be implemented as a semiconductor diode laser based on a compound semiconductor, for example, an InGaAs / GaAs, and may emit high power laser light. The light source may include a single emitter and / or multiple emitters.

[0227] The above-mentioned transmitting optical system (30) transmits laser light generated from a light source to an object (40), and the light reflected from the object (40) is received by the receiving optical system (50). The receiving optical system (50) may be composed of a plurality of optical sensors, and the optical sensors convert the received light into an electrical signal using a photodiode. That is, the image sensors are arranged in a matrix type to convert the light received from an object scanned in each of the horizontal and vertical directions into an electric current. The signal processing unit (60) converts the output of the receiving optical system (50) into a voltage, amplifies it, and then converts the amplified signal into a digital signal using an analog-to-digital converter. The signal processing unit (60) analyzes 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.

[0228] The control unit (10) can receive vehicle speed information and road condition information through a control unit (ECU) or a network. The control unit (10) can receive driving environment information through a network. The driving environment information can include terrain information of the driving section, traffic congestion information, weather, etc. The control unit (10) can adjust the gain based on one or more of the vehicle speed, the road surface condition of the road on which the vehicle is driving, and the driving environment information, and can provide sensor data including the distance to an object and shape information of the object to the free driving device.

[0229] FIG. 8 is a drawing showing an example of measuring an object in a vehicle having the sensor system of the invention, and FIG. 9 is a drawing showing an example of surrounding surveillance in a vehicle having the sensor system of the invention.

[0230] Referring to FIGS. 8 and 9, a vehicle (202) having a sensor system includes a transmitting optical system that projects laser light (201) generated by a light source toward a target scene, and a receiving optical system that receives light (203) reflected from the target or subject (210). The sensor system also includes a lidar system, which typically includes a controller that calculates distance information to the subject (106) from the reflected light, and an element that can scan or provide a specific pattern of light, which may be a static pattern, within a desired range and field of view (FOV). The transmitting and receiving optical system is used to convert the received signal light into measurements representing a point-by-point three-dimensional map of the surrounding environment within the range and FOV of the lidar system.

[0231] 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.

[0232] 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.

[0233] 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 implemented by modification. And 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. Includes first and second lenses arranged in order from the object toward the light source, The above first lens has a convex shape on the object-side surface on the optical axis and has positive power, The second lens has a convex shape on the sensor side along the optical axis, The center spacing between the first and second lenses is greater than the center thickness of each of the first and second lenses, The radius of curvature of the object-side surface of the first lens and the radius of curvature of the sensor-side surface are different from each other, The central thickness of the above first lens is CT1, The central thickness of the above second lens is CT2, The center spacing between the first and second lenses is CG1, Mathematical formula: 0.5 < (CT1+CT2) / CG1 < 1.5 An optical system that satisfies .

2. In paragraph 1, The effective diameters of the object-side and sensor-side surfaces of the above first lens are CA11 and CA12. The effective diameters of the object-side and sensor-side surfaces of the above second lens are CA21 and CA22. Mathematical formula: CT1 < CA12 < CA11 and CT2 < CA21 < CA22 An optical system that satisfies .

3. In the first paragraph, the radius of curvature of the object-side surface of the first lens is L1R1, and the radius of curvature of the sensor-side surface is L1R2. Mathematical formula: CT1 < L1R1 < |L1R2| An optical system that satisfies .

4. In the second paragraph, the radius of curvature of the object-side surface of the second lens is L2R1, and the radius of curvature of the sensor-side surface is L2R2. Mathematical formula: CT2 < |L2R2| < L2R1 An optical system that satisfies .

5. In any one of paragraphs 1 to 4, An optical system wherein the central thicknesses of the first lens and the second lens are the same.

6. In any one of paragraphs 1 to 4, An optical system in which the absolute values ​​of the radius of curvature of the object-side surface of the first lens and the radius of curvature of the sensor-side surface of the second lens are the same.

7. In paragraph 6, An optical system in which the absolute value of the radius of curvature of the sensor-side surface of the first lens and the radius of curvature of the object-side surface of the second lens have the same value.

8. In any one of paragraphs 1 to 4, The above first and second lenses are made of glass, which is an optical system.

9. In any one of paragraphs 1 to 4, An optical system in which the object-side surface and the sensor-side surface of the first and second lenses have a spherical shape.

10. First lens adjacent to the object; a diffuser arranged on the object side of the first lens; and A second lens is disposed on the sensor side of the first lens, The above first lens has a convex shape on the object-side surface on the optical axis, The powers of the first and second lenses above have the same sign, The above first lens is made of glass, The center spacing between the first and second lenses is greater than the center thickness of each of the first and second lenses, The object-side surface of the first lens and the sensor-side surface of the second lens have a symmetrical shape with respect to the center between the first and second lenses, An optical system in which the object-side surface of the first lens and the sensor-side surface of the second lens have the same absolute value of the radius of curvature.

11. An optical system in the 10th paragraph, wherein the sensor-side surface of the first lens and the object-side surface of the second lens have a symmetrical shape with respect to the center between the first and second lenses.

12. An optical system in accordance with claim 11, wherein the sensor-side surface of the first lens and the object-side surface of the second lens have a convex shape or a flat shape.

13. In any one of paragraphs 10 to 12, The light source generates light in the range of 890 nm to 960 nm, The focal lengths of the first and second lenses above have the same value, An optical system in which the refractive indices of the first and second lenses have the same value.

14. In any one of paragraphs 10 to 12, The center spacing between the first and second lenses is CG1, The angle of view of the above optical system is FOV, Mathematical formula: 1 < FOV / CG1 < 3 , and is satisfied with Half of the diagonal length of the above light source is RsH, The optical axis distance from the center of the object-side surface of the first lens to the light source is TTL, Mathematical formula: 1 < TTL / LsH < 10 0 < TTL / FOV < 3 An optical system that satisfies .

Images