Transmission optical system, sensor system, and lidar device

Abstract

A transmission optical system according to the present embodiment comprises a first lens to a third lens sequentially arranged from an object side to a light source side along an optical axis, wherein the second lens has a positive (+) refractive power, the third lens has a positive (+) refractive power, and the distance between the first lens and the second lens along the optical axis is greater than the sum of the thicknesses of the first lens and the second lens.

Description

Transmission optics, sensor systems and lidar devices

[0001] The embodiment relates to a transmitting optical system and a sensor system having the same.

[0002] The embodiment relates to a transmission optical system for LIDAR (Light detection and ranging) and a device having the same.

[0003] An embodiment of the invention relates to a mobile body having a transmitting optical system and system for lidar.

[0004] 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.

[0005] 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.

[0006] 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.

[0007] The present invention provides a transmission optical system having improved optical characteristics and a sensor system and a lidar device having the same.

[0008] The embodiment seeks to provide a transmitting optical system and a sensor system having the same.

[0009] In order to solve the above technical problem, a transmission optical system according to the present embodiment includes first to third lenses sequentially arranged from an object side to a light source side along an optical axis, wherein the second lens has positive (+) refractive power, the third lens has positive (+) refractive power, and a distance between the first lens and the second lens on the optical axis may be greater than the sum of the thicknesses of the first lens and the second lens.

[0010] The second lens may have a meniscus shape convex toward the object side, and the third lens may have a meniscus shape convex toward the object side.

[0011] The distance between the second lens and the third lens on the optical axis may be greater than the thickness of the third lens.

[0012] The distance between the first lens and the second lens on the optical axis may be greater than the distance between the second lens and the third lens.

[0013] The light source can generate light in the range of 890 nm to 960 nm.

[0014] The first lens may be a diffuser that enlarges the angle of view of a first axis perpendicular to the optical axis or a second axis perpendicular to the optical axis and the first axis.

[0015] The object-side surface of the second lens may have the largest effective diameter among the first to third lenses.

[0016] Among the first to third lenses, the refractive index of the first lens may be the smallest, and the refractive index of the second lens may be the largest.

[0017] The following condition can be satisfied. <Condition> 0.5 < CG1 / ∑CG < 1 (In the above condition, CG1 is the center spacing between the first lens and the second lens, and ∑CG is the sum of the spacings between adjacent lenses.)

[0018] The following condition can be satisfied. <Condition> 0 < ∑CT / ∑CG < 1 (In the above condition, ∑CT is the sum of the central thicknesses of the lenses, and ∑CG is the sum of the spacings between adjacent lenses.)

[0019] The following condition can be satisfied. <Condition> 0 < F2 / F3 < 2 (In the above condition, F2 is the focal length of the second lens, and F3 is the focal length of the third lens.)

[0020] The following condition can be satisfied. <Condition> 20 < FOV < 40 (In the above condition, FOV is the field of view of the transmission optical system.

[0021] In order to solve the above technical problem, a lidar device according to the present embodiment includes a transmitting optical system including a light source and first to third lenses sequentially arranged from an object side to a light source side along a first optical axis; and a receiving optical system including an image sensor and fourth to sixth lenses sequentially arranged from an object side to a sensor side along a second optical axis, wherein the second and third lenses have a meniscus shape convex toward the object side on the first optical axis, the fifth and sixth lenses have a meniscus shape convex toward the object side on the second optical axis, the first lens is a diffuser lens, the second and third lenses have positive (+) refractive power, and a distance between the first lens and the second lens may be greater than a thickness of the second lens and a thickness of the third lens on the first optical axis.

[0022] The fifth and sixth lenses may have positive (+) refractive power.

[0023] The first to sixth lenses may be made of glass.

[0024] 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.

[0025] 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. In other words, the transmission optical system can effectively distribute refractive power 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.

[0026] 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.

[0027] The transmission optical system and sensor system according to the embodiment can achieve excellent optical characteristics while satisfying a set field of view through a combination of a glass molded lens and a glass lens. 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.

[0028] FIG. 1 is a side cross-sectional view of a transmission optical system of a lidar according to the first embodiment of the present invention.

[0029] Fig. 2 is a table showing the lens characteristics of the transmission optical system of Fig. 1.

[0030] Fig. 3 is a table showing the aspherical coefficients of lenses in the transmission optical system of Fig. 1.

[0031] Fig. 4 is a graph showing data of diffraction MTF (Modulation Transfer Function) in the transmission optical system of Fig. 1.

[0032] Fig. 5 is a graph showing data on aberration characteristics in the transmission optical system of Fig. 1.

[0033] Fig. 6 is a side cross-sectional view of a transmission optical system of a lidar according to the second embodiment.

[0034] Fig. 7 is a table showing the lens characteristics of the transmission optical system of Fig. 6.

[0035] Fig. 8 is a table showing the aspherical coefficients of lenses in the transmission optical system of Fig. 6.

[0036] Fig. 9 is a graph showing data of diffraction MTF (Modulation Transfer Function) in the transmission optical system of Fig. 6.

[0037] Fig. 10 is a graph showing data on aberration characteristics in the transmission optical system of Fig. 6.

[0038] Fig. 11 is a block diagram showing a sensor system having a transmission optical system of the present invention.

[0039] FIG. 12 is a side cross-sectional view showing a receiving optical system according to one embodiment of the sensor system of FIG. 9.

[0040] FIG. 13 is a side cross-sectional view showing a receiving optical system according to another embodiment of the sensor system of FIG. 9.

[0041] FIG. 14 is a drawing showing an example of measuring an object in a vehicle having a sensor system of the invention.

[0042] Fig. 15 is a drawing showing an example of surrounding surveillance in a vehicle having a sensor system of the invention.

[0043] 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.

[0044] 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) 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” by 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 the downward direction as well as the upward direction based on one component.

[0045] In the description of the invention, the “object-side surface” may mean a surface of a lens facing the object side with respect to the optical axis (OA), the “sensor-side surface” may mean a surface of a lens facing the imaging surface (image sensor) with respect to the optical axis, and the “light source-side surface” may mean a surface of a lens facing the light source with respect to the optical axis. A convex surface of a lens may mean a convex shape in the optical axis or the paraxial region, and a concave surface of a 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 a 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 term "paraxial region" refers to a very narrow region near the optical axis, where the distance a ray falls from the optical axis (OA) is almost zero. Hereinafter, the term "optical axis" may include the center of each lens or a very narrow region near the optical axis.

[0046]

[0047] FIG. 1 is a side cross-sectional view of a transmission optical system of a lidar according to the first embodiment of the present invention, and FIG. 6 is a side cross-sectional view of a transmission optical system of a lidar according to the second embodiment of the present invention.

[0048] Referring to FIGS. 1 and 6, a transmission optical system (110, 210) 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 lens material can be selected from glass or plastic, and the coefficient of linear expansion of glass is lower than that of plastic. Glass lenses are used to suppress changes in the focal point position due to temperature changes. However, when configuring an optical system with spherical glass lenses, there is a limit to reducing the number of lenses, and there is a limit to reducing the size and weight.

[0049] The first and second embodiments of the present invention, the transmission optical systems (110, 210) may include a spherical lens and an aspherical lens. Here, the spherical lens is a lens in which at least one of the object-side surface and the light source-side surface of the lens is spherical. The aspherical lens is a lens in which at least one of the object-side surface and the light source-side surface of the lens is aspherical. The transmission optical systems (110, 210) may include a spherical glass lens and an aspherical glass lens. In addition, by employing the aspherical lens, the optical system (110, 210) may have a reduced overall length (TTL), and the aspherical lens may provide good correction for various aberrations such as spherical aberration and chromatic aberration. In addition, the aspherical lenses may minimize distortion in the peripheral area.

[0050] The optical system (110, 210) may include n lenses, where the nth lens may be the last lens adjacent to the image sensor (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 2, and may be, for example, in the range of 2 to 4. The ratio of spherical lenses to aspherical lenses in the n lenses may be 2:1 or 3:1.

[0051] The transmission optical system (110, 210) may include a first lens made of glass. Glass exhibits minimal expansion and contraction changes due to external temperature changes, and its surface is less susceptible to scratches, preventing surface damage. Accordingly, the object-side lenses in the optical system (110, 210) may be spherical lenses, and the light source-side lenses may be aspherical lenses.

[0052] At least one lens closest to the light source (300) within the optical system (110, 210) may be an aspherical lens. At least one lens closest to the light source (300) may be an aspherical lens. Since the nth or n-1th lenses in the optical system (110, 210) are arranged as aspherical lenses, the light from the exit side of the light source (300) can be emitted through various paths. The aspherical lens may be a glass mold made of injection-molded glass material.

[0053] Within the optical system (110, 210), at least two lenses closest to the object may be made of glass. More than two lenses, for example, two to three lenses, closest to the object may be made of glass. Since glass lenses exhibit a smaller rate of contraction and expansion due to temperature changes than plastic lenses, the glass lenses may be positioned in an area adjacent to the outside of the lens barrel.

[0054]

[0055] Each lens may have an object-side surface and a light source-side surface. The lenses may include lenses having an object-side spherical surface and a light source-side spherical surface, and lenses having an object-side aspherical surface and a light source-side aspherical surface. The number of aspherical lenses in the optical system may be smaller than the number of spherical lenses. The optical system (110, 210) may provide variously refracted light by arranging the aspherical lenses adjacent to the light source (300). The spherical lenses may be made of glass, and the aspherical lenses may be made of glass mold material.

[0056]

[0057] Within the optical system (110, 210), the lens with the largest effective diameter is located in the central region of the optical system (110, 210), is made of glass, and may be a spherical lens. Within the optical system (110, 210), the lens with the smallest effective diameter is located between the aperture (ST) and the lens closest to the object side, and may be a glass lens. In addition, the average effective diameter of the aspherical lenses may be smaller than the average effective diameter of the spherical lenses. Here, the effective diameter of the lens is the average value of the effective diameter of the object-side surface of each lens and the effective diameter of the light source-side surface.

[0058] Each of the lenses (111-113, 211-213) 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. In other words, 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 on a plurality of lenses. In other words, 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.

[0059]

[0060] Among the lenses of the optical system (110, 210), the lens having the largest central thickness may be an aspherical lens, and the lens having the largest edge thickness may be an aspherical lens. Accordingly, various refractive surfaces can be provided, and optical performance can be improved to the periphery. The central thickness of the aspherical lenses can be greater than the central thickness of the spherical lenses. These aspherical lenses can be arranged adjacent to the light source (300) to refract laser light to the entire area of ​​the object-side lenses.

[0061]

[0062] Within the optical system (110, 210), the effective focal length (EFL) can satisfy a range of 8 mm or more and 12 mm or less. The field of view (FOV) of the optical system (110, 210) can satisfy a range of 25 degrees or more and 35 degrees or less. Through this, the optical system can be provided as a standard transmission optical system in a vehicle sensor system. For example, the transmission optical system and 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.

[0063]

[0064] Within the optical system (110, 210), the TTL (Total top length) may be more than 3 times, for example, more than 4 times and less than 5 times, than the LsH. The TTL (Total track length) is the distance from the center of the object-side surface of the first lens to the top surface of the light source (300) on the optical axis (OA). The LsH is twice the distance from the center of the light source (300) to the diagonal end or the maximum diagonal length of the light source (300). In addition, the effective diameter of each lens within the optical system (110, 210) may be greater than the diagonal length of the light source (300).

[0065] Accordingly, the central thickness of each lens along the optical axis (OA) can be increased and the size of the light source (300) can be reduced, thereby providing a vehicle lens optical system. In addition, temperature compensation must be applied in the temperature range that serves as the temperature reliability evaluation standard for automotive electrical components for use in vehicle cameras, that is, from -40°C to +120°C. That is, the lens must be configured so that the focus of the lens is maintained within the set range even when the lens expands or contracts due to temperature changes. The total effective focal length (EFL) can be satisfied to be 8 mm or more and 12 mm or less, and can be configured with lenses made of glass material capable of the aforementioned temperature compensation.

[0066]

[0067] The number of lenses with positive (+) refractive power in the optical system (110, 210) may be equal to or greater than the number of lenses with negative (-) refractive power. The number of lenses with positive (+) refractive power may be 50% or more of the total number of lenses. All lenses with refractive power in the optical system (110, 210) may have positive (+) refractive power. Since the optical system (110, 210) is a mixture of spherical lenses and aspherical lenses made of glass, deterioration of optical performance can be prevented.

[0068]

[0069] The optical system (110, 210) may include a first lens (111, 211), a second lens (112, 212), and a third lens (113, 313) aligned from the object side toward the light source side along the optical axis (OA). The first to third lenses (111-113, 211-213) may be defined as a lens unit. The light source (300) generates a laser beam, and the laser beam may be in the range of 890 nm to 960 nm or 940 nm ±10 nm.

[0070]

[0071] When the radius of curvature is described as an absolute value, among the lenses having curvature within the optical system (110, 210), the lens surface having the minimum radius of curvature with respect to the optical axis (OA) may be the object-side surface of the third lens (113, 213) closest to the light source (300). Among the lenses having curvature within the optical system (110, 210), the lens surface having the maximum radius of curvature with respect to the optical axis (OA) may be the light source-side surface of the second lens (112, 212). By adjusting the radius of curvature of each lens, the chief ray angle (CRA) from the optical axis to the end of the effective area, that is, in the entire field, can be minimized to 0.5 degrees or less, thereby maximizing the transmission efficiency. Here, as the CRA increases, the asymmetry of the divergence angle with respect to the center of the light source (300) of the transmission optical system (110, 210) increases, which may reduce the transmission efficiency.

[0072]

[0073] The optical system (110, 210) or sensor system may include a light source (300). The light source (300) generates laser light with a wavelength ranging from 890 nm to 960 nm or 940 nm ± 10 nm. The light source (300) may be implemented as an InGaAs / GaAs-based semiconductor diode laser and may emit high-power laser light. The light source (300) may include a single emitter and / or multiple emitters. The light source (300) generates laser light in the form of a line light source or a point light source. Here, the length of the light source (300) may be the maximum length in the diagonal direction orthogonal to the optical axis (OA).

[0074]

[0075] The optical system (110, 210) may include an aperture (ST: Stop). The aperture (ST) may control the amount of light emitted from the optical system (110, 210). The aperture (ST) may be arranged on the periphery between the first lens (111, 211) and the second lens (112, 212). The aperture (ST) may be arranged between the first lens (111, 211), which is a diffuser lens, and the second lens (112, 212), which is a spherical lens. The aperture (ST) may be arranged on the periphery of the light source side of the first lens (111, 211).

[0076] The lens surface on which the aperture (ST) is arranged is to more efficiently control and guide the amount of light of the optical system (110, 210). As in the embodiment, the aperture (ST) may be arranged on the light source-side surface of the first lens (111, 211). Alternatively, the aperture (ST) may be arranged on the periphery of the object-side surface or the light source-side surface of the second lens (112, 212). Alternatively, at least one lens selected from among a plurality of lenses, for example, the object-side surface or the light source-side surface of the third lens (113, 213), may function as an aperture. The aperture (ST) may be removed within the transmission optical system (110, 210).

[0077]

[0078] In the optical system (110, 210) of the embodiment, the sum of the refractive indices of the lenses of the lens unit (110, 210) may be in the range of 5 to 6, and the average of the refractive indices may be in the range of 1.70 to 1.80. The sum of the Abbe numbers of each of the lenses may be in the range of 120 to 130, and the average of the Abbe numbers may be 50 or less, for example, in the range of 38 to 45. By adjusting the refractive indices of the lenses within the optical system (100), it is possible to prevent a decrease in transmission efficiency for temperature changes from -45 to 120 degrees and to optimize thermal compensation. In addition, by adjusting the Abbe numbers of the lenses, it is possible to minimize the deviation in transmission efficiency according to wavelength.

[0079]

[0080] The sum of the central thicknesses of the entire lens may be 4 mm or more, for example, in the range of 5 mm to 8 mm, and the average of the central thicknesses may be 3 mm or less, for example, in the range of 1.5 mm to 2.8 mm. The sum of the central spacings between the lenses on the optical axis (OA) may be 11 mm or more, for example, in the range of 12 mm to 14 mm, and may be greater than the sum of the central thicknesses of the lenses. In addition, the average value of the effective diameter of each lens surface of the optical system (110, 210) may be provided as 10 mm or less, for example, in the range of 7 mm to 8 mm. The optical system (110, 210) may adjust the thickness of the lenses to prevent degradation of optical performance for temperature changes from -45 degrees to 120 degrees and to optimize thermal compensation.

[0081]

[0082] In an optical system according to an embodiment of the invention, the angle of view may be greater than 20 degrees, for example, in the range of 25 degrees to 135 degrees. The F number of the optical system or camera module may be 2 or less, for example, in the range of 1.6 to 1.9. The diagonal length of the light source (300) may be 5.234 mm ± 0.5 mm, and may be greater than the sensor height in the vertical direction. The invention may provide a vehicle lidar device that suppresses a change in a focus imaging position due to temperature change by stacking glass lenses and corrects various aberrations by providing an aspherical lens.

[0083]

[0084] Since the embodiment is an optical system applied to a lidar device, the first lens (111) can 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 is used as the first lens (111), and the first lens (111) can have a flat shape to prevent the accumulation of foreign substances. The lidar device can detect the distance, direction, speed, temperature, material distribution, and concentration characteristics to an object while the vehicle is running. Such a lidar device can be used for an advanced driver assistance system (ADAS).

[0085] The optical system (110, 210) 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 the emitted light toward the lenses. Hereinafter, the optical system according to the embodiment will be described in detail.

[0086]

[0087] An optical system according to a first embodiment of the present invention will be described.

[0088] FIG. 1 is a side cross-sectional view of a transmission optical system of a lidar according to the first embodiment of the present invention, FIG. 2 is a table showing lens characteristics of the transmission optical system of FIG. 1, FIG. 3 is a table showing aspherical coefficients of lenses in the transmission optical system of FIG. 1, FIG. 4 is a graph showing data of diffraction MTF (Modulation Transfer Function) in the transmission optical system of FIG. 1, and FIG. 5 is a graph showing data on aberration characteristics in the transmission optical system of FIG. 1.

[0089] Referring to FIGS. 1 to 5, the optical system (110) may include a first lens (111) to a third lens (113). The first to third lenses (111 to 113) may be sequentially arranged along the optical axis (OA) of the optical system (110). Laser light generated from a light source (300) may be emitted through the third lens (113), the second lens (112), and the first lens (111). An aperture (STOP) may be arranged around the periphery of the light source-side surface of the first lens (111).

[0090]

[0091] The first lens (111) may be a lens that is arranged closest to the object side. The first lens (111) may be a lens that is arranged farthest from the light source (300). The first lens (111) may be a diffuser lens. The diffuser lens can spread light over a wider area. The diffuser lens can change the direction and angle of view of light passing through the lens. The angle of view of light passing through the diffuser lens can be expanded or reduced based on the x-axis (horizontal axis) or the y-axis (vertical axis). The first lens (111), which is a diffuser lens, may have a shape of a cylinder lens. For example, the first lens (111) may have a shape in which a plurality of cylinder lenses are arranged. A cylinder lens is a lens that refracts light only about one axis, and can spread light along one axis to generate light in the shape of a line or strip.

[0092] For example, the angle of view of light emitted from a light source (300) after passing through the third lens (113) and the second lens (112) may be approximately 29.6 degrees with respect to the x-axis and the y-axis, respectively. However, after passing through the first lens (111), which is a diffuser lens, the angle of view with respect to the y-axis is maintained, and the angle of view with respect to the x-axis may be expanded to approximately 120 degrees. Here, the angle of view with respect to the x-axis may be referred to as a horizontal angle of view, and the angle of view with respect to the y-axis may be referred to as a vertical angle of view.

[0093] The first lens (111) may include a plastic material or a glass material, and may be made of, for example, glass. At least one of the object-side first surface (S1) and the light source-side second surface (S2) of the first lens (111) may be flat with respect to the optical axis. At least one of the object-side first surface (S1) and the light source-side second surface (S2) of the first lens (111) may have a pattern formed thereon to spread light.

[0094]

[0095] The stop (STOP) can be arranged around the second surface (S2) on the light source side of the first lens (111). The stop (STOP) can control the amount of light emitted from the optical system (110). The stop (STOP) can reduce the TTL within the field of view range, and the optical system can be miniaturized. Accordingly, a decrease in the yield by weight of the optical system can be prevented, and production efficiency can be improved. In addition, the optical system can be miniaturized by reducing the TTL within the field of view range of 20 to 40 degrees.

[0096]

[0097] The second lens (112) may be placed between the first lens (111) and the third lens (113). The second lens (112) may have positive (+) or negative (-) refractive power on the optical axis (OA). The second lens (112) may have positive (+) refractive power. The second lens (112) may include a plastic or glass material, and may be provided as a glass material, for example.

[0098] The third surface (S3) on the object side of the second lens (112) with respect to the optical axis (OA) may be convex, and the fourth surface (S4) on the light source side may be concave. The second lens (112) may have a meniscus shape that is convex toward the object side. The second lens (112) may have a meniscus shape that is concave toward the light source side. At least one of the third surface (S3) and the fourth surface (S4) may be a spherical surface. The fourth surface (S4) may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0099] When the refractive index of the second lens (112) is n2, the condition of 1.75 < n2 < 1.9 can be satisfied. Since the refractive index (n2) of the second lens (112) is higher than that of other lenses, the radius of curvature of the third surface (S3) of the second lens (112) can be increased, and lens manufacturing can be easy. When the refractive index (n2) of the second lens (112) is lower than the condition, the lens surface must be formed to be sharply concave or convex in order to increase the refractive power of the second lens (112). In this case, lens manufacturing is not easy, the lens defect rate increases, and it can cause a decrease in yield.

[0100] When the radius of curvature of the third surface (S3) of the second lens (112) is L2R1 and the radius of curvature of the fourth surface (S4) is L2R2, the condition of 3 < |L2R1-L2R2| < 9 can be satisfied. Through this, the radius of curvature of the third surface (S3) and the fourth surface (S4) of the second lens (112) can be formed similarly to prevent distortion, and the occurrence of aberration and the reduction in the refractive efficiency of light can be prevented.

[0101]

[0102] The third lens (113) may be a lens that is arranged closest to the light source (300). The third lens (113) may be a lens that is arranged farthest from the object side. The third lens (113) may have positive (+) or negative (-) refractive power on the optical axis (OA). The third lens (113) may have positive (+) refractive power. The third lens (113) may include a plastic or glass material, and may be made of glass, for example. The third lens (113) may be a glass mold lens that has an aspherical surface and is made of glass material. The glass mold lens may be manufactured by placing an optical glass ingot inside a mold that will have an aspherical shape and through a heating and compression process.

[0103] The fifth surface (S5) on the object side of the third lens (113) with respect to the optical axis may be convex, and the sixth surface (S6) on the light source side may be concave. The third lens (113) may have a meniscus shape that is convex toward the object side. The third lens (113) may have a meniscus shape that is concave toward the light source side. At least one or both of the fifth surface (S5) and the sixth surface (S6) may be aspherical. The aspherical coefficients of the fifth and sixth surfaces (S5, S6) may be provided as S1 and S2 of L3 in FIG. 3. At least one or both of the fifth surface (S5) and the sixth surface (S6) may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0104] The third lens (113) may be an aspherical lens closest to the light source (300). By arranging two or more aspherical lenses adjacent to the light source (300), aberrations such as spherical aberration and chromatic aberration can be improved by the lens surface having an aspherical surface.

[0105] When the radius of curvature of the fifth surface (S5) of the third lens (113) is L3R1 and the radius of curvature of the sixth surface (S6) is L3R2, the condition of 1 < |L3R1-L3R2| < 4 can be satisfied. Through this, the radius of curvature of the third surface (S3) and the fourth surface (S4) of the second lens (112) can be formed similarly to prevent distortion, and the occurrence of aberration and the reduction in the refractive efficiency of light can be prevented.

[0106]

[0107] Fig. 2 is an example of lens data of the exemplary optical system of Fig. 1. As shown in Fig. 2, the radius of curvature of the optical axis (OA) of the first to third lenses (111, 112, 113), the thickness of the center of the lenses, the distance between the centers of the lenses, the refractive index at the d-line, the Abbe's number, and the size of the semi-aperture can be set.

[0108] The center thicknesses of the first to third lenses (111-113) are represented by CT1 to CT3, the edge thicknesses at the ends of the effective areas of each lens are represented by ET1 to ET3, and the center gap between two adjacent lenses is represented by CG1 to CG3.

[0109] The first to third lenses (111-113) can satisfy the following conditions.

[0110] Condition 1: CT1 < CT3 < CT2

[0111] Condition 2: ET1 < ET2 < ET3

[0112] Condition 3: CG3 < CG2 < CG1

[0113] Condition 4: CT1 < CG3 < CT3 < CG2 < CT2 < CG1

[0114]

[0115] The central thickness (CT2) of the second lens (112) is the largest among the lenses, and the central thickness (CT1) of the first lens (111) is the smallest among the lenses. The maximum central thickness may be at least 10 times, for example, at least 12 times, the minimum central thickness, and the difference between the maximum central thickness and the minimum central thickness may be at least 3.5 mm.

[0116] When explaining the center spacing (CG) between adjacent lenses, the center spacing (CG1) between the first lens (111) and the second lens (112) may be maximum, and the center spacing (CG2) between the second lens (112) and the third lens (113) may be minimum. Here, the difference between the maximum center spacing and the minimum center spacing may be 6 mm or more, for example, in the range of 6 mm to 9 mm. By setting the spacing between the first lens (111) and the second lens (112) to be large, the light may be spread and gathered based on the optical axis, and the aberration correction and optical performance may be improved. In addition, by providing the maximum center spacing between the lenses to be greater than the maximum center thickness of each lens, a transmission optical system that does not increase the center spacing between the lenses may be provided.

[0117]

[0118] In terms of the effective diameter, the lens having the maximum effective diameter may be the second lens (112) located at the center of the optical system (110). The lens having the maximum effective diameter may be a spherical lens made of glass. The lens surface having the maximum effective diameter may be the third surface (S3) of the second lens (112). The lens having the minimum effective diameter may be the first lens (111) located closest to the object side. The lens surface having the minimum effective diameter may be the second surface (S2) of the first lens (111).

[0119] The effective diameter of each of the first to third lenses (111, 112, 113) may be greater than the diagonal length of the light source (300). The effective diameter of the second lens (112) may be greater than the effective diameter of the third lens (113). The effective diameter of the first lens (111) may be smaller than the effective diameter of the second lens (112). The effective diameter of the third lens (113) may be greater than the effective diameter of the first lens (111).

[0120] Both the second lens (112) and the third lens (113) may have positive (+) refractive power. The focal length of the second lens (112) may be smaller than the focal length of the third lens (113). Accordingly, the optical system may have improved MTF characteristics, aberration control characteristics, etc., within the set angle of view range, and may have good optical performance.

[0121]

[0122] As shown in Fig. 3, among the lenses of the first embodiment, the lens surface of the third lens (113) may include an aspherical surface having a 30th-order aspherical surface coefficient. For example, the object-side surface and the light source-side surface of the third lens (113) may be lens surfaces having a 30th-order aspherical surface coefficient. As described above, an aspherical surface having a 30th-order aspherical surface coefficient (a value other than “0”) can significantly change the aspherical shape of the periphery, and thus can effectively correct the optical performance of the periphery of the field of view (FOV).

[0123] Fig. 4 is a graph showing the diffraction MTF (Modulation Transfer Function) at room temperature in the optical system of Fig. 1, and is a graph showing the modulation ratio according to the spatial frequency. The x-axis represents the distance from the center to the edge of the lens, and the y-axis represents the resolution of the lens as a value between 0 and 1. As shown in Fig. 4, it can be seen that the curve of the MTF graph in the first embodiment of the present invention is close to 1 in the center region of the lens, indicating good optical performance.

[0124] Fig. 5 is a graph showing the aberration characteristics at room temperature in the optical system of Fig. 1. In the aberration graph of Fig. 5, spherical aberration (longitudinal spherical aberration), astigmatic field curves, and distortion are measured from left to right. In Fig. 5, the X-axis may represent the focal length (mm) and the degree of distortion (%), and the Y-axis may represent the height of the image. In addition, the graph for spherical aberration is a graph for light in the wavelength bands of about 930 nm, about 940 nm, and about 950 nm, and the graphs for astigmatic aberration and distortion aberration are graphs for light in the wavelength band of about 940 nm. In the aberration diagram of Fig. 5, the closer each curve is to the Y-axis, the better the aberration correction function can be interpreted. Accordingly, it can be seen that the reduction in the luminance ratio (modulation) of Fig. 5 is less than 10%, for example, 5% or less, or is almost unchanged.

[0125]

[0126] An optical system according to a second embodiment of the present invention will be described.

[0127] FIG. 6 is a side cross-sectional view of a transmission optical system of a lidar according to the second embodiment of the present invention, FIG. 7 is a table showing lens characteristics of the transmission optical system of FIG. 6, FIG. 8 is a table showing aspherical coefficients of lenses in the transmission optical system of FIG. 6, FIG. 9 is a graph showing data of diffraction MTF (Modulation Transfer Function) in the transmission optical system of FIG. 6, and FIG. 10 is a graph showing data on aberration characteristics in the transmission optical system of FIG. 6.

[0128] Referring to FIGS. 6 to 10, the optical system (210) may include a first lens (211) to a third lens (213). The first to third lenses (211 to 213) may be sequentially arranged along the optical axis (OA) of the optical system (210). Laser light generated from a light source (300) may be emitted through the third lens (213), the second lens (212), and the first lens (211). An aperture (STOP) may be arranged around the periphery of the light source-side surface of the first lens (211).

[0129]

[0130] The first lens (211) may be a lens that is arranged closest to the object side. The first lens (211) may be a lens that is arranged farthest from the light source (300). The first lens (211) may be a diffuser lens. The diffuser lens can spread light over a wider area. The diffuser lens can change the direction and angle of view of light passing through the lens. The angle of view of light passing through the diffuser lens can be expanded based on the x-axis (horizontal axis) or the y-axis (vertical axis). The first lens (211), which is a diffuser lens, may have a shape of a cylinder lens. For example, the first lens (211) may have a shape in which a plurality of cylinder lenses are arranged. A cylinder lens is a lens that refracts light only about one axis, and can spread light along one axis to generate light in the shape of a line or strip.

[0131] For example, the angle of view of light emitted from a light source (300) after passing through the third lens (213) and the second lens (212) may be approximately 29.6 degrees with respect to the x-axis and the y-axis, respectively. However, after passing through the first lens (211), which is a diffuser lens, the angle of view with respect to the y-axis is maintained, and the angle of view with respect to the x-axis may be expanded to approximately 120 degrees. Here, the angle of view with respect to the x-axis may be referred to as a horizontal angle of view, and the angle of view with respect to the y-axis may be referred to as a vertical angle of view.

[0132] The first lens (211) may include a plastic material or a glass material, and may be, for example, a glass material. At least one of the object-side first surface (S1) and the light source-side second surface (S2) of the first lens (211) may be flat with respect to the optical axis. At least one of the object-side first surface (S1) and the light source-side second surface (S2) of the first lens (211) may have a pattern formed thereon to spread light.

[0133]

[0134] The stop (STOP) can be arranged around the second surface (S2) on the light source side of the first lens (211). The stop (STOP) can control the amount of light emitted from the optical system (210). The stop (STOP) can reduce the TTL within the field of view range, and the optical system can be miniaturized. Accordingly, a decrease in the yield by weight of the optical system can be prevented, and production efficiency can be improved. In addition, the optical system can be miniaturized by reducing the TTL within the field of view range of 20 to 40 degrees.

[0135]

[0136] The second lens (212) may be positioned between the first lens (211) and the third lens (213). The second lens (212) may have positive (+) or negative (-) refractive power on the optical axis (OA). The second lens (212) may have positive (+) refractive power. The second lens (212) may include a plastic or glass material, and may be provided as a glass material, for example.

[0137] The third surface (S3) on the object side of the second lens (212) with respect to the optical axis (OA) may be convex, and the fourth surface (S4) on the light source side may be concave. The second lens (212) may have a meniscus shape that is convex toward the object side. The second lens (212) may have a meniscus shape that is concave toward the light source side. At least one of the third surface (S3) and the fourth surface (S4) may be a spherical surface. The fourth surface (S4) may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0138] When the refractive index of the second lens (212) is n2, the condition of 1.75 < n2 < 1.9 can be satisfied. Since the refractive index (n2) of the second lens (212) is higher than that of other lenses, the radius of curvature of the third surface (S3) of the second lens (212) can be increased, and lens manufacturing can be easy. When the refractive index (n2) of the second lens (212) is lower than the condition, the lens surface must be formed to be sharply concave or convex in order to increase the refractive power of the second lens (212). In this case, lens manufacturing is not easy, the lens defect rate increases, and it may cause a decrease in yield.

[0139] When the radius of curvature of the third surface (S3) of the second lens (212) is L2R1 and the radius of curvature of the fourth surface (S4) is L2R2, the condition of 3 < |L2R1-L2R2| < 9 can be satisfied. Through this, the radius of curvature of the third surface (S3) and the fourth surface (S4) of the second lens (212) can be formed similarly to prevent distortion, and the occurrence of aberration and the reduction in the refractive efficiency of light can be prevented.

[0140]

[0141] The third lens (213) may be a lens that is arranged closest to the light source (300). The third lens (213) may be a lens that is arranged farthest from the object side. The third lens (213) may have positive (+) or negative (-) refractive power on the optical axis (OA). The third lens (213) may have positive (+) refractive power. The third lens (213) may include a plastic or glass material, and may be made of glass, for example. The third lens (213) may be a glass mold lens that has an aspherical surface and is made of glass material. The glass mold lens may be manufactured by placing an optical glass ingot inside a mold that will have an aspherical shape and through a heating and compression process.

[0142] The fifth surface (S5) on the object side of the third lens (213) with respect to the optical axis may be convex, and the sixth surface (S6) on the light source side may be concave. The third lens (213) may have a meniscus shape that is convex toward the object side. The third lens (213) may have a meniscus shape that is concave toward the light source side. At least one or both of the fifth surface (S5) and the sixth surface (S6) may be aspherical. The aspherical coefficients of the fifth and sixth surfaces (S5, S6) may be provided as S1 and S2 of L3 in FIG. 6. At least one or both of the fifth surface (S5) and the sixth surface (S6) may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0143] The third lens (213) may be an aspherical lens closest to the light source (300). By arranging two or more aspherical lenses adjacent to the light source (300), aberrations such as spherical aberration and chromatic aberration can be improved by the lens surface having an aspherical surface.

[0144] When the radius of curvature of the fifth surface (S5) of the third lens (213) is L3R1 and the radius of curvature of the sixth surface (S6) is L3R2, the condition of 1 < |L3R1-L3R2| < 4 can be satisfied. Through this, the radius of curvature of the third surface (S3) and the fourth surface (S4) of the second lens (212) can be formed similarly to prevent distortion, and the occurrence of aberration and the reduction in the refractive efficiency of light can be prevented.

[0145]

[0146] Fig. 7 is an example of lens data of the exemplary optical system of Fig. 6. As shown in Fig. 7, the radius of curvature at the optical axis (OA) of the first to third lenses (211, 212, 213), the thickness at the center of the lenses, the distance between the centers of the lenses, the refractive index at the d-line, the Abbe's number, and the size of the semi-aperture can be set.

[0147] The center thicknesses of the first to third lenses (211-213) are represented by CT1 to CT3, the edge thicknesses at the ends of the effective areas of each lens are represented by ET1 to ET3, and the center gap between two adjacent lenses is represented by CG1 to CG3.

[0148] The first to third lenses (211-213) can satisfy the following conditions.

[0149] Condition 1: CT1 < CT2 < CT3

[0150] Condition 2: ET1 < ET2 < ET3

[0151] Condition 3: CG3 < CG2 < CG1

[0152] Condition 4: CT1 < CT2 < CT3 < CG3 < CG2 < CG1

[0153]

[0154] The central thickness (CT3) of the third lens (213) is the largest among the lenses, and the central thickness (CT1) of the first lens (211) is the smallest among the lenses. The maximum central thickness may be at least 7 times, for example at least 8 times, the minimum central thickness, and the difference between the maximum central thickness and the minimum central thickness may be at least 2 mm.

[0155] When explaining the center spacing (CG) between adjacent lenses, the center spacing (CG1) between the first lens (211) and the second lens (212) may be maximum, and the center spacing (CG2) between the second lens (212) and the third lens (213) may be minimum. Here, the difference between the maximum center spacing and the minimum center spacing may be 3 mm or more, for example, in the range of 4 mm to 6 mm. By setting the spacing between the first lens (211) and the second lens (212) to be large, the light may be spread and gathered based on the optical axis, and the aberration correction and optical performance may be improved. In addition, by providing the maximum center spacing between the lenses to be greater than the maximum center thickness of each lens, a transmission optical system that does not increase the center spacing between the lenses may be provided.

[0156]

[0157] In terms of the effective diameter, the lens having the maximum effective diameter may be the second lens (212) located at the center of the optical system (210). The lens having the maximum effective diameter may be a spherical lens made of glass. The lens surface having the maximum effective diameter may be the third surface (S3) of the second lens (212). The lens having the minimum effective diameter may be the first lens (211) located closest to the object side. The lens surface having the minimum effective diameter may be the second surface (S2) of the first lens (211).

[0158] The effective diameter of each of the first to third lenses (211, 212, 213) may be greater than the diagonal length of the light source (300). The effective diameter of the second lens (212) may be greater than the effective diameter of the third lens (213). The effective diameter of the first lens (211) may be smaller than the effective diameter of the second lens (212). The effective diameter of the third lens (213) may be greater than the effective diameter of the first lens (211).

[0159] Both the second lens (212) and the third lens (213) may have positive (+) refractive power. The focal length of the second lens (212) may be smaller than the focal length of the third lens (213). Accordingly, the optical system may have improved MTF characteristics, aberration control characteristics, etc. within the set angle of view range, and may have good optical performance.

[0160]

[0161] As shown in Fig. 8, among the lenses of the second embodiment, the lens surface of the third lens (213) may include an aspherical surface having a 30th-order aspherical surface coefficient. For example, the object-side surface and the light source-side surface of the third lens (213) may be lens surfaces having a 30th-order aspherical surface coefficient. As described above, an aspherical surface having a 30th-order aspherical surface coefficient (a value other than “0”) can significantly change the aspherical shape of the periphery, and thus can effectively correct the optical performance of the periphery of the field of view (FOV).

[0162] Fig. 9 is a graph showing the diffraction MTF (Modulation Transfer Function) at room temperature in the optical system of Fig. 6, and is a graph showing the modulation ratio according to the spatial frequency. The x-axis represents the distance from the center to the edge of the lens, and the y-axis represents the resolution of the lens as a value between 0 and 1. As shown in Fig. 9, it can be seen that the second embodiment of the present invention has good optical performance since the curve of the MTF graph is close to 1 in the center region of the lens.

[0163] Fig. 10 is a graph showing the aberration characteristics at room temperature in the optical system of Fig. 6. In the aberration graph of Fig. 10, spherical aberration (longitudinal spherical aberration), astigmatic field curves, and distortion are measured from left to right. In Fig. 10, the X-axis may represent the focal length (mm) and the degree of distortion (%), and the Y-axis may represent the height of the image. In addition, the graph for spherical aberration is a graph for light in the wavelength bands of about 930 nm, about 940 nm, and about 950 nm, and the graphs for astigmatic aberration and distortion aberration are graphs for light in the wavelength band of about 940 nm. In the aberration diagram of Fig. 10, the closer each curve is to the Y-axis, the better the aberration correction function can be interpreted. Accordingly, it can be seen that the reduction in the luminance ratio (modulation) of Fig. 10 is less than 10%, for example, less than 5%, or is almost unchanged.

[0164]

[0165] The optical systems (110, 210) according to the first and second embodiments disclosed above can satisfy at least one or two or more of the mathematical equations described below. Accordingly, the optical systems (110, 210) according to the first and second embodiments can have improved optical characteristics. For example, when the optical system (110, 210) satisfies at least one mathematical equation, the optical system (110, 210) can effectively control aberration characteristics such as chromatic aberration and distortion aberration, and can have good optical performance in the center and periphery of the field of view (FOV). In addition, the optical system (110, 210) can have improved resolution. In addition, the thickness of the lens on the optical axis (OA) and the spacing of adjacent lenses on the optical axis (OA) described in the mathematical equations may refer to the embodiments disclosed above.

[0166]

[0167] [Mathematical Formula 1]

[0168] 0.5 < CT2 / CT3 < 1.5

[0169] In mathematical expression 1, CT2 is the central thickness of the second lens (112, 212), and CT3 is the central thickness of the third lens (113, 213). By setting the central thickness (CT2) of the second lens (112, 212) and the central thickness (CT3) of the third lens (113, 213) in mathematical expression 1, it is possible to prevent the rigidity of the second lens (112, 212) from decreasing, and to control factors affecting aberration. In the first and second embodiments, preferably, mathematical expression 1 can satisfy 0.8 < CT2 / CT3 < 1.3.

[0170]

[0171] [Equation 2]

[0172] 1 < CA_L2 / CA_L3 < 2

[0173] Mathematical expression 2 can set the relationship between the size of the effective diameter (CA_L2) of the second lens (112, 212) and the size of the effective diameter (CA_L3) of the third lens (113, 213). When Mathematical expression 2 is satisfied, the TTL suitable for the vehicle optical system is satisfied, and the set angle of view can be satisfied. When it is less than the lower limit of Mathematical expression 2, the effective diameter of the lens arranged in the optical system (110, 210) becomes large, which causes a problem in that the TTL becomes long. When it exceeds the upper limit of Mathematical expression 2, there is a problem in that the angle of view becomes excessively large compared to the angle of view satisfied by the optical system (110, 210). In the first and second embodiments, Mathematical expression 2 can preferably satisfy 1.2 < CA_L2 / CA_L3 < 1.8.

[0174]

[0175] [Equation 3]

[0176] 1.75 < n2 < 1.9

[0177] In mathematical expression 3, n2 is the refractive index of the second lens (112, 212) at the d-line. By setting the refractive index of the second lens (112, 212) high in mathematical expression 3, 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. In the first and second embodiments, mathematical expression 3 can preferably satisfy 1.8 < n2 < 1.9. If it is designed to be lower than the lower limit of mathematical expression 3, the performance of reducing the aberration can be obtained, and the refractive power of the second lens (112, 212) may be weakened, so that light cannot be collected efficiently, which may deteriorate the performance of the optical system. If it is designed to be higher than the upper limit of mathematical expression 3, there is a disadvantage in that it is difficult to obtain materials. In addition, when the refractive index of the second lens (112, 212) is designed to be lower than the lower limit of mathematical expression 4, the radius of curvature of each lens can be increased to increase the refractive power of the lenses in the optical system (110, 210).

[0178]

[0179] [Equation 4]

[0180] 1 < n2 / n3 < 1.5

[0181] In mathematical expression 4, n2 is the refractive index of the second lens (112, 212) at the d-line, and n3 is the refractive index of the third lens (113, 213) at the d-line. In mathematical expression 4, by reducing the difference in the refractive index of the second lens (112, 212) and the third lens (113, 213), the reduction in color dispersion caused by lenses made of glass can be prevented. In the first and second embodiments, mathematical expression 4 can preferably satisfy 1 < n2 / n3 < 1.2.

[0182]

[0183] [Equation 5]

[0184] 1.5 < CG1 / CG2 < 3

[0185] In mathematical expression 5, CG1 refers to the center spacing between the first lens (111, 211) and the second lens (112, 212), and CG2 refers to the center spacing between the second lens (112, 212) and the third lens (113, 213). When mathematical expression 5 is satisfied, the distance between the first lens (111, 211), which is a diffuser, and the second lens (112, 212), which is made of glass, can be sufficiently secured to control the optical path. In the first and second embodiments, mathematical expression 5 can preferably satisfy 1.7 < CG1 / CG2 < 2.8.

[0186]

[0187] [Equation 6]

[0188] 0.5 < CT3 / BFL < 1.5

[0189] In mathematical expression 6, CT3 is the central thickness of the third lens (113, 213), and BFL is the optical axis distance from the center of the light source-side surface of the last lens to the light source (300). That is, BFL is the optical axis distance from the center of the light source-side surface of the third lens (113, 213) to the light source (300). When mathematical expression 6 is satisfied, the emitted light can be transmitted to the entire area of ​​the second lens (112, 212) by the third lens (113, 213). In the first and second embodiments, mathematical expression 6 can preferably satisfy 0.6 < CT3 / BFL < 1.2.

[0190]

[0191] [Equation 7]

[0192] 2 < CG1 / CT2 < 3.5

[0193] In mathematical expression 7, CG1 denotes the center spacing between the first lens (111, 211) and the second lens (112, 212), and CT2 denotes the center thickness of the second lens (112, 212). When mathematical expression 7 is satisfied, the effective diameter of the second lens (112, 212) can be adjusted, and the aberration characteristics of the light traveling can be improved. In the first and second embodiments, mathematical expression 7 can preferably satisfy 2.3 < CG1 / CT2 < 3.3.

[0194]

[0195] [Equation 8]

[0196] 2.5 < CG1 / CT3 < 3.5

[0197] In mathematical expression 8, CG1 denotes the center spacing between the first lens (111, 211) and the second lens (112, 212), and CT3 denotes the center thickness of the third lens (113, 213). When mathematical expression 8 is satisfied, the effective diameter of the third lens (113, 213) can be adjusted, and the aberration characteristics of the light traveling can be improved. In the first and second embodiments, mathematical expression 8 can preferably satisfy 2.8 < CG1 / CT3 < 3.2.

[0198]

[0199] [Equation 9]

[0200] 0.5 < CG1 / ∑CG < 1

[0201] In mathematical expression 9, CG1 denotes the center spacing between the first lens (111, 211) and the second lens (112, 212), and ΣCG is the sum of the spacings between adjacent lenses. When mathematical expression 9 is satisfied, the center spacing between the first lens (111, 211) and the second lens (112, 212), which is the maximum center spacing between the lenses, can be appropriately designed within the optical system (110, 210) to suppress an increase in the size of the second lens (112, 212). In the first and second embodiments, mathematical expression 9 can preferably satisfy 0.6 < CG1 / ΣCG < 0.8.

[0202]

[0203] [Equation 10]

[0204] 0 < CT_Max / CG_Max < 1

[0205] In mathematical expression 10, the maximum central thickness (CT_Max) among the lenses and the maximum gap (CT_Max) between adjacent lenses can be set. When mathematical expression 10 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. In the first and second embodiments, mathematical expression 10 can preferably satisfy 0 < CT_Max / CG_Max < 0.5.

[0206]

[0207] [Equation 11]

[0208] 0 < ∑CT / ∑CG < 1

[0209] In mathematical expression 11, ΣCT is the sum of the central thicknesses of the lenses, and ΣCG is the sum of the spacings between adjacent lenses. When mathematical expression 11 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. In the first and second embodiments, mathematical expression 11 can preferably satisfy 0.3 < ΣCT / ΣCG < 0.8.

[0210]

[0211] [Equation 12]

[0212] 4 < ∑Index < 6

[0213] In mathematical expression 12, ΣIndex means the sum of the refractive indices at the d-line of each of the plurality of lenses. When mathematical expression 12 is satisfied, TTL can be controlled in an optical system (110) in which aspherical lenses and spherical material lenses are mixed. In addition, when the number of spherical material lenses is greater than the number of aspherical material lenses, the sum of TTL and refractive indices can be set. In the first and second embodiments, mathematical expression 12 can preferably satisfy 5 < ΣIndex < 5.5.

[0214]

[0215] [Equation 13]

[0216] 20 < ∑Abbe / ∑Index < 30

[0217] In mathematical expression 13, ΣAbbe means the sum of the Abbe's numbers of each of the plurality of lenses, and ΣIndex means the sum of the refractive indices at the d-line of each of the plurality of lenses. When mathematical expression 13 is satisfied, the optical system (110, 210) can have improved aberration characteristics and resolution. By setting the sum of the Abbe's numbers and the sum of the refractive indices of the lenses in mathematical expression 13, the optical characteristics can be controlled. In the first and second embodiments, mathematical expression 13 can preferably satisfy 20 < ΣAbbe / ΣIndex < 25.

[0218]

[0219] [Equation 14]

[0220] 1 < ΣCT / ΣET < 2

[0221] In mathematical expression 14, ΣCT is the sum of the central thicknesses of the lenses, and ΣET is the sum of the edge thicknesses, i.e., the ends of the effective areas of the lenses. When mathematical expression 14 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. In the first and second embodiments, mathematical expression 14 can preferably satisfy 1.3 < ΣCT / ΣET < 1.6.

[0222]

[0223] [Equation 15]

[0224] 1 < CA_Max / CA_Aver < 2

[0225] In mathematical expression 15, CA_max represents the maximum effective diameter among the object-side and sensor-side surfaces of the lenses, and CA_Aver represents the average of the effective diameters of the object-side and light-source-side surfaces of the lenses. When mathematical expression 15 is satisfied, the optical system can set up a slim and compact sensor device while maintaining optical performance. In the first and second embodiments, mathematical expression 15 can preferably satisfy 1.3 < CA_Max / CA_Aver < 1.8.

[0226]

[0227] [Equation 16]

[0228] 0.1 < CA_Min / CA_Aver < 1

[0229] In mathematical expression 16, CA_Min represents the minimum effective diameter among the object-side and sensor-side surfaces of the lenses, and CA_Aver represents the average of the effective diameters of the object-side and sensor-side surfaces of the lenses. When mathematical expression 16 is satisfied, the optical system can set up a slim and compact sensor device while maintaining optical performance. In the first and second embodiments, mathematical expression 16 can preferably satisfy 0.5 < CA_Min / CA_Aver < 1.

[0230]

[0231] [Equation 17]

[0232] 2 < CA_Max / LsH < 3

[0233] Mathematical expression 17 can be set to the maximum effective diameter (CA_Max) and the maximum diagonal length (LsH) of the light source (300), and when Mathematical expression 17 is satisfied, the optical system can maintain good optical performance and a slim and compact sensor device can be set. Mathematical expression 17 can preferably satisfy 2 < CA_Max / LsH < 2.5 in the first and second embodiments.

[0234]

[0235] [Equation 18]

[0236] 0 < EPD / L3R2 < 1

[0237] In mathematical expression 18, the size of the entrance pupil of the optical system (110) and the radius of curvature of the light source side of the third lens (113, 213) can be set, and when these are satisfied, the optical system (110, 210) can control the emitted light. In the first and second embodiments, mathematical expression 18 can preferably satisfy the condition of 0.4 < EPD / L3R2 < 0.8.

[0238]

[0239] [Equation 19]

[0240] 0 < F2 / F3 < 2

[0241] In mathematical expression 19, F2 is the focal length of the second lens (112, 212), and F3 is the focal length of the third lens (113, 213). When mathematical expression 19 is satisfied, the refractive power of the second lens (112, 212) and the third lens (113, 213) can be controlled, and the TTL and effective focal length (EFL) can be influenced. In the first and second embodiments, mathematical expression 19 can preferably satisfy 0.5 < F2 / F3 < 1.3.

[0242]

[0243] [Equation 20]

[0244] 1 < F2 / F < 2

[0245] In mathematical expression 20, the focal length (F2) of the second lens (112, 212) and the effective focal length (F) of the optical system (110, 210) can be set. When mathematical expression 20 is satisfied, the refractive power of the second lens (112, 212) can be controlled. In the first and second embodiments, mathematical expression 20 can preferably satisfy 1.5 < F2 / F < 2.

[0246]

[0247] [Equation 21]

[0248] Po2 * Po3 > 0

[0249] In mathematical expression 21, Po2 is the refractive power value of the second lens (112, 212), and Po3 is the refractive power value of the third lens (113, 213). That is, the refractive powers of the second lens (112, 212) and the third lens (113, 213) have refractive powers of the same sign, so that light can be effectively guided by the diffuser lens.

[0250]

[0251] [Equation 22]

[0252] 20 mm < TTL < 30 mm

[0253] In mathematical expression 22, TTL (Total track length) means the distance (mm) from the center of the first surface (S1) of the first lens (111, 211) to the upper surface of the light source (300) on the optical axis (OA). In mathematical expression 22, the TTL is set to be greater than 20 mm and less than 25 mm, thereby providing a vehicle optical system. In the first and second embodiments, mathematical expression 22 can preferably satisfy the condition of 20 mm < TTL < 25 mm or TD < TTL.

[0254]

[0255] [Equation 23]

[0256] 5 mm < LsH < 6 mm

[0257] Mathematical expression 23 can set the overall diagonal size (LsH) of the light source (300) and provide an optical system having a vehicle sensor size. Mathematical expression 23 can preferably satisfy 5 mm < LsH < 5.5 mm in the first and second embodiments.

[0258]

[0259] [Equation 24]

[0260] 2.5 mm < BFL < 4 mm

[0261] In mathematical expression 24, BFL is the optical axis distance from the light source (300) to the center of the sensor side of the last lens. When mathematical expression 24 is satisfied, the assemblability of components can be improved through the gap between the light source (300) and the last lens, and the joint reliability can be improved. In the first and second embodiments, mathematical expression 24 can preferably satisfy 2.8 mm < BFL < 4 mm. When the BFL is less than the range of mathematical expression 24, some of the light emitted from the light source may not be emitted, which may cause a decrease in resolution. When the BFL exceeds the range of mathematical expression 24, stray light may be emitted, which may deteriorate the aberration characteristics of the optical system.

[0262]

[0263] [Equation 25]

[0264] 8 mm < F < 12 mm

[0265] Mathematical expression 25 can set the overall focal length (F) to suit the vehicle optical system. Mathematical expression 25 can preferably satisfy 9 mm < F < 11 mm in the first and second embodiments.

[0266]

[0267] [Equation 26]

[0268] 20 < FOV < 40

[0269] In mathematical expression 26, FOV (Field of view) means the angle of view (Degree) of the optical system (110), and a vehicle optical system having an angle of view (F0V) exceeding 25 degrees can be provided. In the first and second embodiments, FOV can preferably satisfy 25 < FOV < 35.

[0270] In Equation 26, the range of the vehicle optical system can be set by the angle of view. The horizontal light source length is based on 5.234 mm ± 0.5 mm. In addition, if Equation 26 is satisfied, the rate of change in the effective focal length and the rate of change in the angle of view when the temperature changes from room temperature to high temperature can be set to 5% or less, for example, 0 to 5%.

[0271]

[0272] [Equation 27]

[0273] 1.5 < TTL / CA_Max < 2.5

[0274] In mathematical expression 27, CA_max means the largest effective diameter (mm) among the object-side and light-source-side surfaces of a plurality of lenses, and TTL (Total track length) means the distance (mm) from the vertex of the first surface (S1) of the first lens (111, 211) to the image surface of the light source (300) on the optical axis (OA). Mathematical expression 27 sets the relationship between the total optical axis length of the optical system and the maximum effective diameter, thereby providing an improved vehicle optical system. Mathematical expression 27 can preferably satisfy 1.8 < TTL / CA_Max < 2.2 in the first and second embodiments.

[0275]

[0276] [Equation 28]

[0277] 4 < TTL / LsH < 5

[0278] Mathematical expression 28 can set the total optical axis length (TTL) of the optical system and the maximum diagonal length (LsH) of the light source (300). When mathematical expression 28 is satisfied, the optical system (110, 210) can have TTL for application to the vehicle light source (300), thereby providing improved image quality. Mathematical expression 28 can preferably satisfy 4.1 < TTL / LsH < 4.8 in the first and second embodiments.

[0279]

[0280] [Equation 29]

[0281] 0 < BFL / LsH < 1

[0282] Mathematical expression 29 can set the optical axis distance (BFL) between the light source (300) and the last lens and the maximum diagonal length (LsH) of the light source (300). When Mathematical expression 29 is satisfied, the optical system (110) can secure the BFL (Back focal length) for applying the size of the vehicle light source (300), can set the distance between the last lens and the light source (300), and can have good optical characteristics in the field of view (FOV). Mathematical expression 29 can preferably satisfy 0.3 < BFL / LsH < 0.8 in the first and second embodiments.

[0283]

[0284] [Equation 30]

[0285] 5 < TTL / BFL < 9

[0286] Mathematical expression 30 can set the total optical axis length (TTL) of the optical system and the optical axis spacing (BFL) between the light source (300) and the last lens. When mathematical expression 30 is satisfied, the optical system (110, 210) can secure BFL. Mathematical expression 30 can preferably satisfy 5.5 < TTL / BFL < 8.5 in the first and second embodiments.

[0287]

[0288] [Equation 31]

[0289] 2 < TTL / F < 3

[0290] Mathematical expression 31 can set the total focal length (F) and the total optical axis length (TTL) of the optical system (110). Accordingly, an optical system for a driver assistance system can be provided. Mathematical expression 31 can preferably satisfy 2 < TTL / F < 2.5 in the first and second embodiments. When Mathematical expression 31 is satisfied, the optical system (110, 210) 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 temperature. When it is less than the lower limit of Mathematical expression 31, the refractive power of the lenses needs to be increased, making it difficult to correct spherical aberration or distortion aberration, and when it exceeds the upper limit of Mathematical expression 31, the effective diameter or TTL of the lenses becomes long, which may cause a problem of the imaging lens system becoming large.

[0291]

[0292] [Equation 32]

[0293] 2 < F / BFL < 4

[0294] Mathematical expression 32 can set the total focal length (F) of the optical system (110) and the optical axis distance (BFL) between the light source (300) and the last lens. When Mathematical expression 32 is satisfied, the optical system (110, 210) 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 (110, 210) can minimize the distance between the last lens and the light source (300), and thus can have good optical characteristics in the angle of view (FOV). Mathematical expression 32 can preferably satisfy 2 < F / BFL < 3.5 in the first and second embodiments.

[0295]

[0296] [Equation 33]

[0297] 1 < F / LsH < 2.5

[0298] Mathematical expression 33 can set the total focal length (F, mm) of the optical system (110, 210) and the maximum diagonal length (LsH) of the light source (300). When mathematical expression 33 is satisfied, the vehicle light source (300) can have improved aberration characteristics in terms of size. Mathematical expression 33 can preferably satisfy 1.5 < F / LsH < 2 in the first and second embodiments.

[0299]

[0300] [Equation 34]

[0301] 1 < F / EPD < 2.5

[0302] Mathematical expression 34 can set the overall focal length (F) and entrance pupil size of the optical system (110, 210). Accordingly, the overall brightness of the optical system can be controlled. Mathematical expression 34 can preferably satisfy 1.5 < F / EPD < 2 in the first and second embodiments.

[0303]

[0304] [Equation 35]

[0305] 0 < EPD / LsH / FOV < 0.1

[0306] Mathematical expression 35 can set the relationship between the entrance pupil size (EPD), the length of half the maximum diagonal length of the image sensor (LsH), and the field of view. Accordingly, the overall size and brightness of the optical system can be controlled. Mathematical expression 35 can preferably satisfy 0 < EPD / LsH / FOV < 0.05 in the first and second embodiments.

[0307]

[0308] [Equation 36]

[0309] 13 < FOV / F# < 20

[0310] Mathematical expression 36 can establish the relationship between the angle of view and the F number (F#) of the optical system (110, 210). Mathematical expression 36 can preferably satisfy 14 < FOV / F# < 17 in the first and second embodiments. Here, F# is provided to be 1.9 or less, so as to provide a bright image.

[0311]

[0312] [Equation 37]

[0313]

[0314] In mathematical expression 37, Z can represent Sag, which is the distance from any position on the aspherical surface to the vertex of the aspherical surface along the optical axis. Y can represent the distance from any position on the aspherical surface to the optical axis in the direction perpendicular to the optical axis. c can represent the curvature of the lens, and K can represent the conic constant. In addition, A, B, C, D, E, and F can represent aspheric constants.

[0315]

[0316] The optical system (110, 210) according to the first and second embodiments can satisfy at least one or two or more mathematical expressions from mathematical expressions 1 to 37. In this case, the optical system (110, 210) can have improved optical characteristics. Specifically, when the optical system (110, 210) satisfies at least one of mathematical expressions 1 to 37, the optical system (110, 210) can have improved resolution and improve aberration and distortion characteristics. In addition, the optical system (110, 210) can secure a BFL (Back focal length) for applying a vehicle light source (300), can compensate for optical characteristic degradation due to temperature change, and can minimize the distance between the last lens and the light source (300), thereby having good optical performance within the field of view (FOV).

[0317]

[0318] Table 1 shows the items of the mathematical formulas described above in the optical systems (110, 210) of the first and second embodiments, including the TTL (Total track length) (mm), BFL (Back focal length), effective focal length (F), LsH, effective diameter (CA), 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 sixth surface (S6), focal lengths (F2, F3), angle of view (FOV), edge thickness (ET), F number, etc. of the optical systems (110, 210).

[0319]

[0320] Item 1 Example 2 Example 1 Item 1 Example 2 Example 2 F10.00010.000ET10.30000.3000F216.09319.252ET21.93431.3148F321.47515.082ET32.86072.2972ΣIndex5.1735.178FOV29.629.6ΣA bbe128.900121.579EPD5.575.29ΣCT7.4475.691BFL3.003.92ΣCG13.84012.706TD 21.3518.45TTL24.345622.3693LsH5.185.23F-number1.79621.8903SD21.0518.15

[0321] Table 2 shows the result values ​​for the mathematical expressions 1 to 36 described above in the optical system (110, 210) according to the first and second embodiments. Referring to Table 2, it can be seen that the optical system (110, 210) satisfies at least one, two or more, or three or more of the mathematical expressions 1 to 36. In detail, it can be seen that the optical system (110, 210) according to the first and second embodiments satisfies all of the mathematical expressions 1 to 36. Accordingly, the optical system (110, 210) can have good optical performance within the field of view (FOV) and can have excellent optical characteristics.

[0322]

[0323] <h2 style=";text-align:left;direction:ltr">수학식제1실시예제2실시예10.5 < CT2 / CT3 < 1.51.2000.90521 < CA_L2 / CA_L3 < 21.6181.39731.75 < n2 < 1.91.8471.83541 < n2 / n3 < 1.51.0201.01451.5 < CG1 / CG2 < 32.7081.88360.5 < CT3 / BFL < 1.51.0910.72972 < CG1 / CT2 < 3.52.5723.20882.5 < CG1 / CT3 3.53.0862.90490.5 < CG1 / ∑CG < 10.7300.653100 < CT_Max / CG_Max < 10.3890.344110 < ∑CT / ∑CG < 10.5380.448124 < ∑Index < 65.1735.1781320 < ∑Abbe / ∑Index < 3024.91623.479141 < ΣCT / ΣET < 21.4621.455151 < CA_Max / CA_Aver < 21.6041.475160.1 < CA_Min / CA_Aver < 10.6660.709172 < CA_Max / LsH < 32.4082.079180 < EPD / L3R2 < 10.7610.596190 < F2 / F3 < 20.7491.276201 < F2 / F < 21.6091.92521Po2 * Po3 > 0만족만족2220 < TTL < 3024.34622.369235 < LsH < 65.1825.234242.5 < BFL < 43.0013.919258 < F < 1210.00010.0002620 < FOV < 4029.60029.600271.5 < TTL / CA_Max < 2.51.9512.056284 < TTL / LsH < 54.6984.274290 < BFL / LsH < 10.5790.749305 < TTL / BFL < 98.1145.708312 < TTL / F < 32.4352.237322 < F / BFL < 43.3332.552331 < F / LsH < 2.51.9301.911341 < F / EPD < 2.51.7961.890350 < EPD / LsH / FOV < 0.10.0360.0343613 < FOV / F# < 2016.48015.659.

[0324] Fig. 11 is a block diagram of a sensor system having a transmission optical system according to an embodiment of the present invention.

[0325] Referring to FIG. 11, 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).

[0326] 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.

[0327] The light source driving unit (20) supplies power to and drives the light source included in the transmission optical system (30). The light source generates 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 terrain information of the driving section, traffic congestion information, weather, etc.

[0328] The wavelength of the laser light generated from the light source may be in the range of 890 nm to 960 nm or 940 nm ±10 nm. The laser light source may be implemented as an InGaAs / GaAs-based semiconductor diode laser and may emit high-power laser light. The light source may include a single emitter and / or multiple emitters.

[0329] The 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 light sensors, and the light 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.

[0330] The signal processing unit (60) converts the output of the receiving optical system (50) into a voltage, amplifies it, and then converts the amplified signal into a digital signal using an analog-to-digital converter. The signal processing unit (60) analyzes the digital data using a TOF (Time of Flight) algorithm or a phase-shift algorithm to detect the distance to the object (40) and the shape of the object.

[0331] 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.

[0332]

[0333] FIG. 12 is a side cross-sectional view showing a receiving optical system according to one embodiment of the sensor system of FIG. 9, and it can be confirmed that it has a shape symmetrical to the transmitting optical system according to the first embodiment of FIG. 1.

[0334] Referring to FIG. 12, the receiving optical system (100) may include fourth to sixth lenses (101, 102, 103) sequentially arranged from the object side to the image sensor (150).

[0335] The fourth to sixth lenses (101, 102, 103) may have shapes that are symmetrical with respect to the object side with respect to the first to third lenses (111, 112, 113) of the transmission optical system (110) of FIG. 1. For example, the fourth lens (101) may be symmetrical with respect to the object side with respect to the first lens (111), the fifth lens (102) may be symmetrical with respect to the object side with respect to the second lens (112), and the sixth lens (103) may be symmetrical with respect to the object side with respect to the third lens (113).

[0336] The first and second lenses (111, 112) and the fourth and fifth lenses (101, 102) are made of glass and are spherical lenses that are not injection-molded. The third lens (113) and the sixth lens (103) are made of glass and are aspherical lenses that are injection-molded. In other words, the materials of the first to third lenses (111, 112, 113) and the fourth to sixth lenses (101, 102, 103) are symmetrical.

[0337] The position of the aperture (ST) arranged between the first lens (111) and the second lens (112) corresponds to the aperture (ST) arranged between the fourth lens (101) and the fifth lens (102). The aperture of the transmitting optical system (110) can be defined as the second aperture, and the aperture of the receiving optical system (100) can be defined as the first aperture.

[0338] The fourth lens (101) may have positive (+) or negative (-) refractive power on the optical axis (OA). The fourth lens (101) may be a diffuser lens. The diffuser lens may change the direction and angle of view of light passing through the lens. The angle of view of light passing through the diffuser lens may be enlarged or reduced based on the x-axis (horizontal axis) or the y-axis (vertical axis). The fourth lens (101), which is a diffuser lens, may have a shape of a cylinder lens. For example, the fourth lens (101) may have a shape in which a plurality of cylinder lenses are arranged. A cylinder lens is a lens that refracts light only about one axis, and can spread the light along one axis to generate light in the shape of a line or strip.

[0339] The fourth lens (101) may include a plastic material or a glass material, and may be, for example, a glass material. At least one of the object-side first surface (S1) and the light-source-side second surface (S2) of the fourth lens (101) may be flat with respect to the optical axis. At least one of the object-side first surface (S1) and the light-source-side second surface (S2) of the fourth lens (101) may have a pattern formed thereon.

[0340]

[0341] The fifth lens (102) may be positioned between the fourth lens (101) and the sixth lens (103). The fifth lens (102) may have positive (+) or negative (-) refractive power on the optical axis (OA). The fifth lens (102) may have positive (+) refractive power. The fifth lens (102) may include a plastic or glass material, and may be provided as a glass material, for example.

[0342] The third surface (S3) on the object side of the fifth lens (102) may be convex with respect to the optical axis (OA), and the fourth surface (S4) on the light source side may be concave. The fifth lens (102) may have a meniscus shape that is convex toward the object side. The fifth lens (102) may have a meniscus shape that is concave toward the light source side. At least one of the third surface (S3) and the fourth surface (S4) may be a spherical surface. The fourth surface (S4) may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0343]

[0344] The sixth lens (103) may be a lens that is arranged closest to the image sensor (150). The sixth lens (103) may be a lens that is arranged farthest from the object side. The sixth lens (103) may have positive (+) or negative (-) refractive power on the optical axis (OA). The sixth lens (103) may have positive (+) refractive power. The sixth lens (103) may include a plastic or glass material, and may be made of glass, for example. The sixth lens (103) may be a glass mold lens that has an aspherical surface and is made of glass material. The glass mold lens may be manufactured by placing an optical glass ingot inside a mold that will have an aspherical shape and through a heating and compression process.

[0345] The fifth surface (S5) on the object side of the sixth lens (103) with respect to the optical axis may be convex, and the sixth surface (S6) on the light source side may be concave. The sixth lens (103) may have a meniscus shape that is convex toward the object side. The sixth lens (103) may have a meniscus shape that is concave toward the light source side. At least one or both of the fifth surface (S5) and the sixth surface (S6) may be aspherical. At least one or both of the fifth surface (S5) and the sixth surface (S6) may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0346]

[0347] An optical filter may be placed between the sixth lens (103) positioned closest to the image sensor (150) and the image sensor (150). The optical filter may be a band pass filter that passes a laser beam in the range of 890 nm to 960 nm or 940 nm ±10 nm. The optical filter may pass light having a wavelength corresponding to the laser beam transmitted from the transmission optical system of the lidar device and block light corresponding to the remaining ambient light.

[0348] A cover glass may be placed between the sixth lens (103) positioned closest to the image sensor (150) and the image sensor (150). The cover glass protects the upper portion of the image sensor (150) and may prevent a decrease in the reliability of the image sensor (150). The cover glass may be a protective glass.

[0349] The image sensor (150) can detect light that has sequentially passed through the lenses. The image sensor (150) can include a device capable of detecting incident light, such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor).

[0350] The shape of each lens surface of the first to third lenses (111, 112, 113) may be symmetrical to the shape of each lens surface of the fourth to sixth lenses (101, 102, 103). Accordingly, the laser light emitted from the transmitting optical system (110) can be reflected by an object and then the reception efficiency of the receiving optical system (100) can be increased.

[0351]

[0352] FIG. 13 is a side cross-sectional view showing a receiving optical system according to another embodiment of the sensor system of FIG. 9, and it can be confirmed that it has a shape symmetrical to the transmitting optical system according to the second embodiment of FIG. 6.

[0353] Referring to FIG. 13, the receiving optical system (200) may include fourth to sixth lenses (201, 202, 203) sequentially arranged from the object side to the image sensor (150).

[0354] The fourth to sixth lenses (201, 202, 203) may have shapes that are symmetrical with respect to the object side with respect to the first to third lenses (211, 212, 213) of the transmission optical system (210) of FIG. 6. For example, the fourth lens (201) may be symmetrical with respect to the object side with respect to the first lens (211), the fifth lens (202) may be symmetrical with respect to the object side with respect to the second lens (212), and the sixth lens (203) may be symmetrical with respect to the object side with respect to the third lens (213).

[0355] The first and second lenses (211, 212) and the fourth and fifth lenses (201, 202) are made of glass and are spherical lenses that are not injection-molded. The third lens (213) and the sixth lens (203) are made of glass and are aspherical lenses that are injection-molded. In other words, the materials of the first to third lenses (211, 212, 213) and the fourth to sixth lenses (201, 202, 203) are symmetrical.

[0356] The position of the aperture (ST) arranged between the first lens (211) and the second lens (212) corresponds to the aperture (ST) arranged between the fourth lens (201) and the fifth lens (102). The aperture of the transmitting optical system (210) can be defined as the second aperture, and the aperture of the receiving optical system (200) can be defined as the first aperture.

[0357] The fourth lens (201) may have positive (+) or negative (-) refractive power on the optical axis (OA). The fourth lens (201) may be a diffuser lens. The diffuser lens may change the direction and angle of view of light passing through the lens. The angle of view of light passing through the diffuser lens may be enlarged or reduced based on the x-axis (horizontal axis) or the y-axis (vertical axis). The fourth lens (201), which is a diffuser lens, may have a shape of a cylinder lens. For example, the fourth lens (201) may have a shape in which a plurality of cylinder lenses are arranged. A cylinder lens is a lens that refracts light only about one axis, and can spread the light along one axis to generate light in the shape of a line or strip.

[0358] The fourth lens (201) may include a plastic material or a glass material, and may be, for example, a glass material. At least one of the object-side first surface (S1) and the light source-side second surface (S2) of the fourth lens (201) with respect to the optical axis may be flat. At least one of the object-side first surface (S1) and the light source-side second surface (S2) of the fourth lens (201) may have a pattern formed thereon.

[0359]

[0360] The fifth lens (202) may be positioned between the fourth lens (201) and the sixth lens (203). The fifth lens (202) may have positive (+) or negative (-) refractive power on the optical axis (OA). The fifth lens (202) may have positive (+) refractive power. The fifth lens (202) may include a plastic or glass material, and may be provided as a glass material, for example.

[0361] The third surface (S3) on the object side of the fifth lens (202) with respect to the optical axis (OA) may be convex, and the fourth surface (S4) on the light source side may be concave. The fifth lens (202) may have a meniscus shape that is convex toward the object side. The fifth lens (202) may have a meniscus shape that is concave toward the light source side. At least one of the third surface (S3) and the fourth surface (S4) may be a spherical surface. The fourth surface (S4) may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0362]

[0363] The sixth lens (203) may be a lens that is arranged closest to the image sensor (150). The sixth lens (203) may be a lens that is arranged farthest from the object side. The sixth lens (203) may have positive (+) or negative (-) refractive power on the optical axis (OA). The sixth lens (203) may have positive (+) refractive power. The sixth lens (203) may include a plastic or glass material, and may be made of glass, for example. The sixth lens (203) may be a glass mold lens that has an aspherical surface and is made of glass material. The glass mold lens may be manufactured by placing an optical glass ingot inside a mold that will have an aspherical shape and through a heating and compression process.

[0364] The fifth surface (S5) on the object side of the sixth lens (203) with respect to the optical axis may be convex, and the sixth surface (S6) on the light source side may be concave. The sixth lens (203) may have a meniscus shape that is convex toward the object side. The sixth lens (203) may have a meniscus shape that is concave toward the light source side. At least one or both of the fifth surface (S5) and the sixth surface (S6) may be aspherical. At least one or both of the fifth surface (S5) and the sixth surface (S6) may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0365]

[0366] An optical filter may be placed between the sixth lens (203) positioned closest to the image sensor (150) and the image sensor (150). The optical filter may be a band pass filter that passes a laser beam in the range of 890 nm to 960 nm or 940 nm ±10 nm. The optical filter may pass light having a wavelength corresponding to the laser beam transmitted from the transmission optical system of the lidar device and block light corresponding to the remaining ambient light.

[0367] A cover glass may be placed between the image sensor (150) and the sixth lens (203) positioned closest to the image sensor (150). The cover glass protects the upper portion of the image sensor (150) and may prevent a decrease in the reliability of the image sensor (150). The cover glass may be a protective glass.

[0368] The image sensor (150) can detect light that has sequentially passed through the lenses. The image sensor (150) can include a device capable of detecting incident light, such as a CCD (Charge Coupled Device) or a CMOS (Complementary Metal Oxide Semiconductor).

[0369] The shape of each lens surface of the first to third lenses (211, 212, 213) may be symmetrical to the shape of each lens surface of the fourth to sixth lenses (201, 202, 203). Accordingly, the laser light emitted from the transmitting optical system (210) can be reflected by an object and then the reception efficiency of the receiving optical system (200) can be increased.

[0370]

[0371] FIG. 14 is a drawing showing an example of measuring an object in a vehicle having the sensor system of the invention, and FIG. 15 is a drawing showing an example of surrounding surveillance in a vehicle having the sensor system of the invention.

[0372] Referring to FIGS. 14 and 15, a vehicle (502) having a sensor system includes a transmitting optical system that projects laser light (501) generated by a light source toward a target scene, and a receiving optical system that receives light (503) reflected from the target or subject (510). The sensor system also includes a lidar system, which typically includes a controller that calculates distance information to the subject (506) 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 field of view of the lidar system.

[0373] 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.

[0374] Also shown is a schematic diagram illustrating the two-dimensional field of view and range requirements of a typical surround view LIDAR system (500) for a vehicle (502). For example, adaptive cruise control may require a field of view and range (504) with a narrower field of view compared to the side view "surround view" field of view and range (506), but with a long range requirement. Typically, the sensor functions of a vehicle 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."

[0375] While the present invention describes a LIDAR system in the context of an automobile, where LIDAR is widely used for autonomous, self-driving, or driver-assisted vehicles, it should be understood that the embodiments can be applied to any vehicle. Other types of vehicles include robots, tractors, trucks, airplanes, drones, boats, and ships.

[0376]

[0377] The features, structures, effects, etc. described in the embodiments above are included in at least one embodiment of the present invention, and are not necessarily limited to just one embodiment. Furthermore, the features, structures, effects, etc. exemplified in each embodiment can be combined or modified in other embodiments by those skilled in the art to which the embodiments pertain. Therefore, the contents related to such combinations and modifications should be construed as falling within the scope of the present invention.

[0378] In addition, although the above description focuses on examples, these are merely examples and do not limit the present invention. Those skilled in the art to which the present invention pertains will appreciate that various modifications and applications not exemplified above are possible without departing from the essential characteristics of the present invention. For example, each component specifically shown in the examples can be modified and implemented. In addition, differences related to such modifications and applications should be interpreted as being included within the scope of the present invention defined in the appended claims.

Claims

1. Includes first to third lenses sequentially arranged from the object side to the light source side along the optical axis, The above second lens has positive (+) refractive power, The above third lens has positive (+) refractive power, A transmission optical system wherein the distance between the first lens and the second lens on the optical axis is greater than the sum of the thicknesses of the first lens and the second lens.

2. In paragraph 1, The above second lens has a meniscus shape convex toward the object side, The above third lens is a transmission optical system having a meniscus shape convex toward the object side.

3. In paragraph 1, An optical system wherein the distance between the second lens and the third lens on the optical axis is greater than the thickness of the third lens.

4. In paragraph 1, An optical system wherein the distance between the first lens and the second lens on the optical axis is greater than the distance between the second lens and the third lens.

5. In paragraph 1, The above light source is a transmitting optical system that generates light in the range of 890 nm to 960 nm.

6. In paragraph 1, A transmission optical system in which the first lens is a diffuser that expands the angle of view of a first axis perpendicular to the optical axis or a second axis perpendicular to the optical axis and the first axis.

7. In paragraph 1, A transmission optical system in which the object-side surface of the second lens has the largest effective diameter among the first to third lenses.

8. In paragraph 1, A transmission optical system in which the refractive index of the first lens among the first to third lenses is the smallest and the refractive index of the second lens is the largest.

9. In any one of paragraphs 1 to 8, A transmitting optical system satisfying the following conditions. <Conditional expression> 0.5 < CG1 / ∑CG < 1 (In the above conditional expression, CG1 is the center spacing between the first lens and the second lens, and ΣCG is the sum of the spacings between adjacent lenses.) 10. In any one of paragraphs 1 to 8, A transmitting optical system satisfying the following conditions. <Conditional expression> 0 < ∑CT / ∑CG < 1 (In the above conditional expression, ΣCT is the sum of the central thicknesses of the lenses, and ΣCG is the sum of the gaps between adjacent lenses.)

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