Optical transmission system, optical reception system, sensor system, and lidar device

Abstract

An optical reception system according to an embodiment of the present invention may comprise: first to fifth lenses arranged along an optical axis from an object toward a sensing unit; and an optical filter spaced apart from the sensing unit and disposed between the third lens and the fourth lens, wherein the first to fifth lenses include aspherical lenses and spherical lenses, the number of which is greater than the number of the aspherical lenses, the optical axis distance from the optical filter to the surface of the sensing unit is D1, the optical axis distance from the sensor-side surface of the fifth lens closest to the sensing unit to the surface of the sensing unit is BFL and satisfies a mathematical expression: BFL < D1, the effective diameter of the first lens is larger than the effective diameters of the remaining lenses, and the effective diameter of the fourth lens is smaller than the effective diameter of the first lens.

Description

Transmitting optical system, receiving optical system, sensor system and lidar device

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

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

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

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

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

[0006] The present invention seeks to provide a transmitting and receiving optical system, a sensor system and a lidar device having improved thermal compensation characteristics.

[0007] According to an embodiment of the invention, a transmission optical system includes first to fifth lenses aligned along an optical axis from an object toward a sensing unit; and an optical filter spaced apart from the sensing unit and disposed between the third lens and the fourth lens, wherein the first to fifth lenses include aspherical lenses and spherical lenses having a number of lenses greater than the number of aspherical lenses, an optical axis distance from the optical filter to a surface of the sensing unit is D1, an optical axis distance from a sensor-side surface of the fifth lens closest to the sensing unit to the surface of the sensing unit is BFL, and a mathematical expression: BFL < D1 is satisfied, and an effective diameter of the first lens may be larger than the effective diameters of the remaining lenses, and an effective diameter of the fourth lens may be smaller than the effective diameter of the first lens.

[0008] The receiving optical system includes an aperture arranged on the object-side periphery of the optical filter, and an optical axis distance from the aperture to the surface of the sensing unit is SD and may satisfy the mathematical expression: 1 < SD / D1 < 1.2. An optical axis distance from the object-side surface of the first lens to the optical filter is D2 and may satisfy the mathematical expression: 0.5 < D1 / D2 < 1.5. The fourth lens and the fourth lens may be spherical lenses, the second lens may be an aspherical lens, and the fifth lens may be an aspherical lens. The first lens may be a spherical lens, and an effective diameter of the fourth lens may be larger than an effective diameter of the first lens, and the effective diameter may be an average of effective diameters of the object-side surface and the sensor-side surface of each lens. The center thickness of the fifth lens is CT5, and the optical axis distance from the center of the object-side surface of the first lens to the surface of the sensing unit is TTL, and can satisfy the mathematical formula: CT5 < TTL / 3 < D1.

[0009] In the receiving optical system, the optical filter is a band pass filter that passes a range of 890 nm to 960 nm, and the center distance between the third lens and the fourth lens may be the largest among the center distances between the first lens to the fifth lens. The first lens includes a convex object-side surface and a concave sensor-side surface on the optical axis, and the effective diameter of the object-side surface of the first lens may be the largest among the effective diameters of the lens surfaces from the first lens to the fifth lens. The third lens may have a biconvex shape on the optical axis, the fourth lens may have a meniscus shape convex toward the object on the optical axis, and the fifth lens may have a convex object-side surface and a concave sensor-side surface on the optical axis.

[0010] In the above receiving optical system, the first lens may have negative refractive power, the fifth lens may have positive refractive power, and the third and fourth lenses may have positive refractive power. Half of the diagonal length of the sensing unit is ImgH, and the optical axis distance from the optical filter to the surface of the sensing unit is D1, and the mathematical formula: ImgH < BFL < D1 may be satisfied.

[0011] According to an embodiment of the invention, the optical axis distance from the surface of the first lens to the surface of the sensing unit is TTL and satisfies the mathematical formula: 20 mm < TTL < 60 mm, and the first to fifth lenses may be made of glass.

[0012] According to an embodiment of the invention, a lidar device includes a light source, a transmitting optical system having first to fourth lenses aligned with a first optical axis from an object toward the light source, and a receiving optical system having a sensing unit and fifth to ninth lenses aligned with a second optical axis from an object toward the sensing unit, wherein the fifth to ninth lenses include spherical lenses and aspherical lenses, the number of spherical lenses in the receiving optical system is greater than the number of aspherical lenses, the receiving optical system includes an optical filter arranged between the spherical lenses, the transmitting optical system includes spherical lenses and aspherical lenses, the number of aspherical lenses in the transmitting optical system is smaller than the number of spherical lenses, the transmitting optical system includes an aperture and a diffuser arranged on the object side more than the first lens, an emission area of ​​the light source is different from a light-receiving area of ​​the sensing unit, and the first to fourth lenses and the fifth to ninth lenses may be made of glass.

[0013] According to an embodiment of the invention, the first lens of the transmission optical system may have a meniscus shape convex toward the object side and have positive power, and the third lens may have positive power. The fourth lens may have a meniscus shape convex toward the object side and have negative power, and the effective diameter of the third lens may be larger than the effective diameter of the fourth lens.

[0014] According to the optical system of the 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. The lidar transmission optical system of the invention can have good optical characteristics in a low temperature 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 according to a temperature change and the focal length of each lens changes as a result, mutual compensation can be made by the glass mold lens and the glass lens. That is, the transmission optical system can effectively perform refractive power distribution in a low temperature to high temperature range, and can prevent or minimize changes in optical characteristics in a low temperature to high temperature range. Therefore, the optical system and sensor system according to the embodiment can maintain improved optical characteristics in various temperature ranges.

[0015] The lidar transmitting optical system of the invention may have lenses having set thicknesses, refractive powers, and spacings with adjacent lenses. Accordingly, the optical system and sensor system according to the embodiment may have improved MTF characteristics, aberration control characteristics, resolution characteristics, etc. in a set field of view range, and may have good optical performance in the periphery of the field of view. The transmitting optical system and sensor system according to the embodiment may satisfy the set field of view and implement excellent optical characteristics through a mixture of glass mold lenses and glass lenses. As a result, the optical system may provide a slimmer vehicle sensor system. Accordingly, the optical system and sensor system may be provided to various applications and devices, and may have excellent optical characteristics even in harsh temperature environments, such as when exposed to the exterior of a vehicle or when inside a vehicle at high temperatures in the summer.

[0016] According to an embodiment, a receiving optical system can have improved optical characteristics. Specifically, by positioning a bandpass filter near a stop in the receiving optical system, the incident angle of light incident on the filter can be minimized. Accordingly, the transmittance range of the bandpass filter can be widely utilized depending on the incident angle of light on the bandpass filter. The receiving optical system of the inventive lidar can maximize the effect of receiving light emitted from the transmitting optical system. The receiving optical system of the inventive lidar can have good optical characteristics in a temperature range from low to high temperature. Specifically, a plurality of lenses included in the receiving optical system can have set materials, refractive powers, and refractive indices. Accordingly, when the refractive index of each lens changes due to a change in temperature, and the focal length of each lens changes as a result, mutual compensation can be made by the glass mold lens and the glass lens. That is, the receiving optical system can effectively distribute refractive power in a temperature range from low to high temperature, and can prevent or minimize changes in optical characteristics in a temperature range from low to high temperature. Therefore, the optical system and sensor system according to the embodiment can maintain improved optical properties over a wide temperature range.

[0017] The receiving optical system of the lidar 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. The receiving optical system and sensor system according to the embodiment may satisfy the set field of view and implement excellent optical characteristics through a combination of glass mold lenses and glass lenses. As a result, the optical system may provide a slimmer vehicle sensor system.

[0018] Therefore, the transmitting and receiving optical system and sensor system can be provided for various applications and devices, etc., and can have excellent optical properties even in harsh temperature environments, such as when exposed to the outside of a vehicle or inside a vehicle at high temperatures in summer.

[0019] Fig. 1 is a side cross-sectional view of a transmission optical system of a lidar according to an embodiment.

[0020] Fig. 2 (A) is a drawing showing the first lens and diffuser of the transmission optical system of Fig. 1, and (B) is an example of the back view of the diffuser.

[0021] Figure 3 is an example of an optical path through a lens array of a diffuser of a comparative example and an embodiment.

[0022] Fig. 4 is a table showing the lens characteristics of the transmission optical system of Fig. 1.

[0023] Fig. 5 is a table showing the aspherical coefficients of lenses in the transmission optical system of Fig. 1.

[0024] Fig. 6 is a graph showing data of diffraction MTF (Modulation Transfer Function) according to low temperature, room temperature, and high temperature in the transmission optical system of Fig. 1.

[0025] Fig. 7 is a graph showing data on the aberration characteristics of the transmission optical system of Fig. 1 at low temperatures.

[0026] Fig. 8 is a graph showing data on the aberration characteristics of the transmission optical system of Fig. 1 at room temperature.

[0027] Fig. 9 is a graph showing data on the aberration characteristics of the transmission optical system of Fig. 1 at high temperatures.

[0028] Figure 10 is data on the distortion characteristics of the transmission optical system of Figure 1.

[0029] Fig. 11 is a side cross-sectional view of a receiving optical system of a lidar according to an embodiment.

[0030] Fig. 12 is a table showing the lens characteristics of the receiving optical system of Fig. 11.

[0031] Fig. 13 is a table showing the aspherical coefficients of lenses in the receiving optical system of Fig. 11.

[0032] Fig. 14 is data on the distortion characteristics of the receiving optical system of Fig. 11.

[0033] Figure 15 is a graph showing data of diffraction MTF (Modulation Transfer Function) according to low temperature, room temperature, and high temperature in the receiving optical system of Figure 11.

[0034] Fig. 16 is a graph showing data on the aberration characteristics of the receiving optical system of Fig. 11 at low temperatures.

[0035] Fig. 17 is a graph showing data on the aberration characteristics of the receiving optical system of Fig. 11 at room temperature.

[0036] Fig. 18 is a graph showing data on the aberration characteristics of the receiving optical system of Fig. 11 at high temperatures.

[0037] FIG. 19 is a graph comparing the transmittance curves when the incident angle of the main beam measured by an automatic optical inspection (AOI) device is 0 degrees, 20 degrees, and 40 degrees by a filter according to an embodiment of the invention.

[0038] Fig. 20 is a block diagram showing a sensor system having the receiving optical system of Fig. 11.

[0039] FIG. 21 is a drawing showing an example of measuring an object in a vehicle having a sensor system of the invention.

[0040] Fig. 22 is a drawing showing an example of surrounding surveillance in a vehicle having a sensor system of the invention.

[0041] 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.

[0042] The terminology used in the embodiments of the present invention is for the purpose of describing the embodiments and is not intended to limit the present invention. In this specification, the singular may also include the plural unless specifically stated in the phrase, and when it is described as “A and (or at least one (or more) of B, C)”, it may include one or more of all combinations that can be combined with A, B, and C. In addition, when describing components of the embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only for distinguishing the components from other components, and are not limited by the nature, order, or sequence of the components. In addition, when it is described that a component is “connected,” “coupled,” or “connected” to another component, it may include not only cases where the component is directly connected, coupled, or connected to the other component, but also cases where the component is “connected,” “coupled,” or “connected” due to another component between the component and the other component. Additionally, when it is described as being formed or arranged "above or below" each component, "above" or "below" includes not only cases where the two components are in direct contact with each other, but also cases where one or more other components are formed or arranged between the two components. Furthermore, when it is expressed as "above" or "below", it can include the meaning of a downward direction as well as an upward direction based on one component.

[0043] 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. The convexity of one surface of the lens may mean a convex shape in the optical axis or the paraxial region, and the concaveness of one surface of the lens may mean a concave shape in the optical axis or the paraxial region. The radius of curvature, center thickness, and optical axis spacing between lenses described in the table for lens data may mean values ​​(unit: mm) in the optical axis. The vertical direction may mean a direction perpendicular to the optical axis, and the end of a lens or lens surface may mean the end of an effective area of ​​a lens through which incident light passes. The size of the effective diameter of the lens surface may have a measurement error of up to ±0.4 mm depending on the measurement method, etc. The above-mentioned near-axis region refers to a very narrow region near the optical axis, and is a region where the distance from the optical axis (OA) of a light ray is almost 0. Hereinafter, the optical axis may include the center of each lens or a very narrow region near the optical axis. In the specification, * indicates multiplication.

[0044]

[0045] The sensor system of the invention includes a transmitting optical system and a receiving optical system, and can be installed inside or outside a vehicle to monitor a driver or sense external objects or lanes. The material of each of the lenses of the transmitting optical system and the receiving optical system can be selected from glass or plastic, and since the coefficient of linear expansion of each lens is smaller for glass than for plastic, lenses made of glass can be used to suppress changes in the focal imaging position due to temperature changes. However, when the optical system is configured with spherical glass lenses, there is a limit to reducing the number of lenses, and there is a limit to reducing the size and weight.

[0046] Transmission optical system

[0047] Referring to FIG. 1, the transmission optical system (110) 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 on the optical axis 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 on the optical axis is aspherical. The transmission optical system (110) may include a spherical glass lens and an aspherical glass lens. In addition, by employing an aspherical lens, the optical system (110) 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.

[0048] The optical system (110) may include n lenses, 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 less than or equal to 5, for example, may be in the range of 3 to 5. The ratio of spherical lenses to aspherical lenses in the n lenses may be any one of 3:1 and 2:2. The transmission optical system (110) may include a first lens (111) closest to the object formed of a glass material. The glass material exhibits little expansion and contraction change due to external temperature changes, and its surface is not easily scratched, thereby preventing surface damage. Accordingly, in the optical system (110), the lenses adjacent to the object may be spherical lenses, and the lens(es) adjacent to the light source may be arranged as aspherical lenses.

[0049] The last lens close to the light source (116) within the optical system (110) may be an aspherical lens. The nth lens within the optical system (110) may be arranged as an aspherical lens. Accordingly, the light from the exit side of the light source (116) may be emitted through various paths. The aspherical lens may be a glass mold in which a glass material is injection-molded. As another example, at least two lenses closest to the light source (116) may be aspherical lenses. The lenses within the optical system (110) may be made of glass. Since the rate of contraction and expansion due to temperature change of the glass material lenses is smaller than that of the plastic material lenses, the glass material lenses may be arranged in an area adjacent to the outside within the lens barrel.

[0050]

[0051] Each of the above lenses 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 (110) may be smaller than the number of spherical lenses. The optical system (110) may provide variously refracted light by arranging the aspherical lenses adjacent to the light source (116). The spherical lenses may be made of glass, and the aspherical lenses may be made of glass mold. Among the lenses of the optical system (110), the lens having the highest refractive index may be a spherical lens, and the lens having the highest Abbe number may be a spherical lens. Accordingly, since the lens having the highest refractive index is arranged on the object side, it is easy to change the radius of curvature of the lenses after the second lens, and the central thickness may be increased.

[0052]

[0053] Within the optical system (110), the lens having the largest effective diameter is positioned closest to the aspherical lens, and may be made of glass and may be a spherical lens. Within the optical system (110), the lens having the smallest effective diameter is positioned closest to the aperture (ST) or the object, and may be a glass lens. The effective diameter of the aspherical lens may be smaller than the average effective diameter of the spherical lenses. Here, the effective diameter of the lens is an average value of the effective diameter of the object-side surface of each lens and the effective diameter of the light source-side surface. Each of the lenses (111-114) 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 an effective diameter through which the incident light is refracted to implement optical characteristics. The ineffective area may be arranged around the effective area. The ineffective area may be an area through which effective light is not incident from the plurality of lenses. That is, the non-effective area may be an area unrelated to the optical characteristics. In addition, an end of the non-effective area may be an area fixed to a lens barrel (not shown) that accommodates the lens.

[0054] Among the lenses of the optical system (110), the lens having the maximum center thickness may be a spherical lens, and the lens having the maximum edge thickness may be a spherical lens. Accordingly, the center distance (CG2) between the lens (112) having the maximum thickness and the lens (113) having the maximum effective diameter may be spaced apart, thereby reducing the number of lenses in the optical system. The center thickness of the aspherical lens may be smaller than the average of the center thicknesses of the spherical lenses. Such an aspherical lens may be arranged adjacent to the light source (116) to refract laser light to the entire area of ​​the object-side lenses.

[0055]

[0056] Within the optical system (110), the TTL (Total top length) may be more than 5 times, for example, more than 5 times and less than 15 times, than the LsH. The TTL (Total track length) is the distance from the center of the object-side surface of the first lens (111) to the surface of the light source (116) on the optical axis (OA). The LsH is the distance from the center of the light source (116) to the diagonal end or half of the maximum diagonal length of the light source (116). In addition, the effective diameter of each lens within the optical system (110) may be greater than the diagonal length of the light source (116). Within the optical system (110), the effective focal length (EFL) may be more than 5 mm and the angle of view (FOV) may be less than 80 degrees or 42±10 degrees, so that 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 ADAS (Advanced Driving Assistance System) installed inside or outside a vehicle.

[0057] The above optical system (110) may have a condition of TTL / (2*LsH) of more than 2.5 times and less than 7.5 times. Accordingly, the central thickness of each lens along the optical axis (OA) can be increased and the size of the light source (116) 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 remains within the set range even when the lens expands or contracts due to temperature changes. The total effective focal length (EFL) can be more than 5 mm, for example, in the range of 8 mm to 20 mm, and can be configured with lenses made of glass capable of the aforementioned temperature compensation. The transmitting optical system (110) can implement a narrow angle by having a longer effective focal length than the receiving optical system.

[0058] In the optical system (110), the number of lenses having positive (+) refractive power may be one or more, and the number of lenses having negative (-) refractive power may be one or more. Since the optical system (110) is a mixture of spherical lenses and aspherical lenses made of glass, optical performance degradation can be prevented. The effective diameter of the lens closest to the object side in the optical system (110) may be smaller than the effective diameter of the lens closest to the light source (116). Accordingly, the brightness of the receiving optical system can be controlled. By controlling the effective diameter size of each lens, the optical system (110) can control the incident light to compensate for the deterioration of optical characteristics due to resolution and temperature change, and can improve chromatic aberration control characteristics. By controlling the effective diameters of the lenses, there is an effect of enabling miniaturization of the optical system (110).

[0059]

[0060] The optical system (110) may include a first lens (111), a second lens (112), a third lens (113), and a fourth lens (114) aligned from the object side toward the light source side along the optical axis (OA). The first to fourth lenses (111, 112, 113, 114) may be defined as a lens unit. The light source (116) generates a laser beam, and the wavelength of the laser beam may be in the range of 890 nm to 960 nm or 940 nm ± 10 nm. As another example, the wavelength of the laser beam may be 1550 nm ± 10 nm. The light source (116) may be implemented as an InGaAs / GaAs-based semiconductor diode laser and may emit high-power laser light. The light source (116) may include a single emitter and / or multiple emitters. The above light source (116) generates laser light in the form of a line light source or a point light source.

[0061]

[0062] When the radius of curvature is described as an absolute value, the lens surface having the minimum radius of curvature with respect to the optical axis (OA) within the optical system (110) may be the light source-side surface of the fourth lens (114) among the spherical surfaces. Accordingly, the center spacing between the second lens (112) and the third lens (113) may be spaced apart to be greater than the center spacing between the first lens (111) and the second lens (112). The lens surface having the maximum radius of curvature within the optical system (110) may be the light source-side surface of the third lens (113). By adjusting the radius of curvature of each lens, the CRA (Chief ray angle) may be minimized to 0.5 degrees or less from the optical axis to the end of the effective area, that is, throughout the entire field, thereby maximizing transmission efficiency. Here, as the CRA increases, the asymmetry of the divergence angle with respect to the center of the light source (116) of the transmission optical system (110) increases, which may reduce the transmission efficiency.

[0063] The optical system (110) may include an aperture (ST: Stop). The aperture (ST) may control the amount of light emitted from the optical system (110). The aperture (ST) may be arranged on the periphery of the object-side surface of the first lens (111). The aperture (ST) may be spaced apart from the object-side surface of the first lens (111) by a predetermined distance (CG0). The optical axis distance (CG0) between the first lens (111) and the aperture (ST) may be 2 mm or more. Since the aperture (ST) is spaced apart from the object-side surface of the first lens (111) by the distance, an increase in the effective length of the diffuser (119) may be suppressed.

[0064]

[0065] As shown in (A)(B) of FIG. 2, a diffuser (119) may be placed between an object and the aperture (ST). The diffuser (119) may include a lens array, for example, a micro lens array, on at least one of an incident side surface and an exit side surface. The micro lens array may be placed on the exit side surface of the diffuser (119). Each of the micro lenses (119A) may have a long length in a first direction (X, vertical direction) and may be spaced apart from each other in a plurality in a second direction (Y, horizontal direction). The diffuser (119) may have a polygonal shape, for example, a rectangular shape. Each of the lenses may have a cylindrical cross-section and a convex hemispherical shape. The diffuser (119) may refract light emitted through the first lens (111) to emitted parallel light. Since the light emitted through the first lens (111) is provided as parallel light, as shown in FIG. 12, the radius of curvature of the object-side surface of the fifth lens (101) of the receiving optical system can be increased like a flat surface. Accordingly, the amount of light incident through the fifth lens (101) can be increased. The diagonal length of the diffuser (119) may be larger than the maximum diameter of the light source (116) and smaller than the maximum diameters of the first to fourth lenses (111-114). The emission-side surface of the diffuser (119) is the object-side surface, and the incident-side surface is the light source-side surface. The area of ​​the object-side surface of the diffuser (119) may be larger than the area of ​​the effective diameter of the aperture (ST), that is, the hole area.

[0066]

[0067] The transmitting optical system (110) having the first to fourth lenses (111-114) can spread the horizontal field of view (HFOV) of the receiving optical system (100) to 120 degrees or more because the object-side diffusers (119) are arranged in a one-dimensional shape. That is, since the diffusers (119) are arranged as a cylinder-type lens array having a long length in the first direction (vertical direction), only the horizontal field of view (HFOV) can be increased without a significant change in the vertical field of view (VFOV). The aspect ratio of the transmitting optical system (110) and the receiving optical system (100) by the diffusers (119) is the ratio of the width to the height of the image sensor, and can be expressed as H:V=1:7. This has the effect of enabling optical matching by means of a diffuser (119) even if the aspect ratios of the transmitting optical system and the receiving optical system are different compared to the aspect ratio of the existing receiving optical system, which is H:V=3.43:1. Accordingly, the size of the transmitting / receiving optical system can be reduced.

[0068] In the optical system (110) of the embodiment, the sum of the refractive indices of the lenses may be 6 or more, for example, in the range of 6 to 10, 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 160 or less, for example, in the range of 100 to 160, and the average of the Abbe numbers may be 45 or less, for example, in the range of 20 to 45. By adjusting the refractive indices of the lenses in the transmission optical system (110), it is possible to prevent a decrease in transmission efficiency for a temperature change of -45 to 120 degrees and to optimize thermal compensation. In addition, by adjusting the Abbe numbers of the lenses, it is possible to minimize a deviation in transmission efficiency according to a wavelength.

[0069] The sum of the central thicknesses of the entire lens may be 13 mm or more, for example, in the range of 13 mm to 23 mm, and the average of the central thicknesses may be 3.9 mm or more, for example, in the range of 3.9 mm to 5.9 mm. The sum of the central spacings between the lenses on the optical axis (OA) may be 25 mm or less, for example, in the range of 8 mm to 20 mm, and may be less 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 transmission optical system (110) may be provided as 20 mm or less, for example, in the range of 10 mm to 20 mm. The transmission optical system (110) 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.

[0070]

[0071] In the transmitting optical system (110) according to an embodiment of the invention, the angle of view may be less than 80 degrees, for example, in the range of 30 to 60 degrees. The F number of the optical system or camera module may be 1.8 or less, for example, in the range of 1 to 1.8 or 1.2 to 1.7. The diagonal length of the light source (116) may be 8.26 mm ± 0.5 mm, and may be greater than the height of the image sensor in the vertical direction. The invention can provide a vehicle lidar device that suppresses changes in the focus imaging position due to temperature changes by stacking glass lenses and corrects various aberrations by providing an aspherical lens. Since the embodiment is an optical system applied to a lidar device, the first lens (111) may be provided with a glass material. This has the advantage that the glass material is more resistant to scratches than the plastic material and is not sensitive to external temperature. In order to more effectively prevent scratches caused by foreign substances or when placed inside a vehicle, a glass lens may be used as the first lens (111), and the object-side surface of the first lens (111) may have a convex shape to prevent external foreign substances from accumulating. The lidar device can detect the distance, direction, speed, temperature, material distribution, and concentration characteristics to an object when the vehicle is running. Such a lidar device can be used for an advanced driver assistance system (ADAS). The optical system (110) according to an 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 an embodiment will be described in detail.

[0072]

[0073] Referring to FIGS. 1 and 4, the transmission optical system (110) may include a first lens (111) to a fourth lens (114) sequentially aligned from the object toward the light source along the optical axis (OA). Laser light generated from the light source (116) may be emitted by the fourth lens (114), the third lens (113), the second lens (112), and the first lens (111) and irradiated to the subject through a diffuser (119).

[0074] The above aperture (ST) may be arranged closer to the diffuser (119) than the object-side surface of the first lens (111). The aperture (ST) may be spaced apart from the vertex of the first surface (S1) of the first lens (111) by a predetermined distance (CG0). Since the first lens (111) adjacent to the light source side of the aperture (ST) has positive refractive power (F1 > 0), the first lens (111) can refract the emitted light in the direction of the optical axis, and can suppress an increase in the distance from the light source side or the rear side lens of the first lens (111).

[0075] The above diffuser (119) is arranged on the object side of the aperture (ST) and can refract light passing through the aperture (ST) toward the subject as parallel light. As shown in FIGS. 2 and 3, the diffuser (119) of the embodiment uses a micro lens array to control the path of passing light. At this time, a change in the Field of Illumination (FOI) occurs in the on-axis direction separate from the direction in which the light travels. In the comparative example, it can be seen that the FOI changes in the off-axis direction after passing through the micro lens array. Here, when looking at the optical path after passing through the diffuser (119), the comparative example has an optical path of F*θ, and the embodiment has an optical path of f*sinθ.

[0076]

[0077] The power of the first lens (111) may be positive (+) or negative (-) on the optical axis (OA). The power of the first lens (111) is positive (+). The first lens (111) may include a plastic material or a glass material, and may be, for example, a glass material. The first lens (111) made of a glass material can reduce changes in the center position and the radius of curvature due to temperature changes according to the surrounding environment, and can protect the output side surface of the optical system (110). The object-side first surface (S1) of the first lens (111) with respect to the optical axis may be convex, and the light source-side second surface (S2) may be concave. The first surface (S1) and the second surface (S2) may have spherical surfaces. The first lens (111) may have a meniscus shape that is convex toward the object side. In contrast, the first surface (S1) may have a concave shape and the second surface (S2) may have a convex shape in the optical axis (OA). Since the first surface (S1) is convex and the second surface (S2) is concave, the emitted light can be refracted in a direction close to the optical axis (OA), the gap between the first and second lenses (111, 112) can be reduced, and the effective diameter of the first lens (111) can be reduced. The effective diameter of the light source-side surface of the second lens (112) can be designed to be smaller than the effective diameter of the object-side surface by the shape of the lens surface of the first lens (111). The first surface (S1) of the first lens (111) can be provided from the optical axis (OA) to the end of the effective area, i.e., the edge, without a critical point. The second surface (S2) of the first lens (111) can be provided without a critical point.

[0078] When the refractive index of the first lens (111) is Nd1, the condition of Nd1 > 1.70 or 2.0 > Nd1 > 1.70 can be satisfied. Since the refractive index (Nd1) of the first lens (111) is higher than that of an aspherical lens, the radius of curvature of the first surface (S1) of the first lens (111) can be larger than that of an aspherical lens, and lens manufacturing can be easy. When the refractive index (Nd1) of the first lens (111) is smaller than the above condition, the lens surface must be formed to be sharply concave or convex in order to increase the refractive power of the first and second lenses (111, 112). In this case, lens manufacturing is not easy, the lens defect rate increases, and this may cause a decrease in yield.

[0079] Since the first lens (111) is arranged on the light source side of the aperture (ST) and diffuser (119), it can be provided with the thinnest thickness among the lenses. Since the first lens (111) is arranged on the light source side of the aperture (ST) and diffuser (119), it can have the smallest effective diameter among the lenses. Since the first lens (111) is arranged on the light source side of the aperture (ST) and diffuser (119), it can have a radius of curvature that is larger than the average of the absolute values ​​of the radii of curvature of the second lens (112).

[0080]

[0081] The second lens (112) may be arranged between the first lens (111) and the third lens (113). The power of the second lens (112) may be positive (+) or negative (-) on the optical axis (OA). The power of the second lens (112) is negative (-). The second lens (112) may include a plastic or glass material, and may be provided as a spherical lens made of glass, for example. The object-side third surface (S3) of the second lens (112) with respect to the optical axis (OA) may be concave, and the light source-side fourth surface (S4) may be convex. The third and fourth surfaces (S3, S4) may be spherical. The third and fourth surfaces (S3, S4) may be provided without a critical point from the optical axis (OA) to the end of the effective area. Alternatively, the third surface (S3) may be convex and the fourth surface (S4) may be concave. Alternatively, the second lens (112) may be concave on both sides.

[0082] When the refractive index of the second lens (112) is Nd2, the condition of Nd2 > 1.7 or 2.0 > Nd2 > 1.70 can be satisfied. Since the refractive index (Nd2) of the second lens (112) is higher than the refractive index of the aspherical lens, the radius of curvature of the third surface (S3) of the second lens (112) can be larger than that of the aspherical lens, and the lens can be easily manufactured. Since the fourth surface (S4) on the light source side of the second lens (112) is convex and has a small radius of curvature, the center spacing between the second lens (112) and the third lens (113) can be spaced apart. In addition, 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 │L2R2│ > │L2R1│ can be satisfied. When this condition is satisfied, the light emitted by the third and fourth surfaces (S3, S4) can be efficiently refracted, so that the effective diameter of the first lens (111) does not increase, and the TTL can be reduced. If the condition of │L2R2│ < │L2R1│ is satisfied, the center spacing between the first and second lenses (111, 112) is reduced, a lot of aberration may occur on the light source side of the second lens (112), and the refractive efficiency of light may be reduced on the object side.

[0083]

[0084] The power of the third lens (113) may be positive (+) or negative (-) on the optical axis (OA). The power of the third lens (113) may be positive (+). The third lens (113) may include a plastic or glass material, and may be, for example, glass. 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 on the optical axis (OA). At least one or both of the fifth surface (S5) and the sixth surface (S6) may be spherical. 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. Alternatively, the third lens (113) may have a meniscus shape that is convex on both sides or convex toward the light source. Alternatively, the third lens (113) may have a concave shape on both sides on the optical axis.

[0085] When the refractive index of the third lens (113) is Nd3, the condition of Nd3 > 1.7 or 2.0 > Nd3 > 1.70 can be satisfied. The first to third lenses (111, 112, 113) may be made of the same glass material. The first to third lenses (111, 112, 113) may have the same refractive index. When the Abbe number of the third lens (113) is Vd3, the condition of Vd3 < Vd4 can be satisfied. In addition, the condition of Nd4 < Nd3 can be satisfied. Nd4 is the refractive index of the fourth lens (114). Vd4 is the Abbe number of the fourth lens (114).

[0086]

[0087] The power of the fourth lens (114) may have a positive (+) or negative (-) refractive power on the optical axis (OA). The power of the fourth lens (114) is negative. The fourth lens (114) may include a plastic or glass material, and may be provided as a glass material. The fourth lens (114) may be an injection-molded glass mold. The seventh surface (S7) on the object side of the fourth lens (114) with respect to the optical axis may be convex, and the eighth surface (S8) on the light source side may be concave. The fourth lens (114) may have a meniscus shape that is convex toward the object on the optical axis (OA). At least one or both of the seventh surface (S7) and the eighth surface (S8) may be aspherical. The aspherical coefficients of the seventh and eighth surfaces (S7, S8) may be provided as S7 and S8 of L4 in FIG. 5. The seventh surface (S7) may be provided from the optical axis (OA) to the end of the effective area without a critical point. The eighth surface (S8) may be provided from the optical axis (OA) to the end of the effective area without a critical point. As another example, at least one of the seventh surface (S7) and the eighth surface (S8) may have a critical point. Here, the critical point may be a point where the sign of the slope value with respect to the optical axis (OA) and the direction perpendicular to the optical axis (OA) changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the slope value is 0. In addition, the critical point may be a point where the slope value of a tangent passing through the lens surface increases and then decreases, or a point where the slope value decreases and then increases. Alternatively, the fourth lens (114) may have a convex meniscus shape toward the light source. Alternatively, the fourth lens (114) may have a concave shape on both sides along the optical axis (OA).

[0088]

[0089] The effective diameter of the fourth lens (114) may be smaller than the effective diameter of the third lens (113). The effective diameter of the third lens (113) may be the largest among the lenses. In addition, the effective diameters of the first lens (111) and the last n-th lens may be smaller than the effective diameters of at least two lenses arranged between the first lens (111) and the last n-th lens. The fourth lens (114) may have a lower refractive index than the refractive indices of the first, second, and third lenses (111, 112, and 113) and may have a higher Abbe number than the Abbe numbers of the first, second, and third lenses (111, 112, and 113). The powers of the first lens (111) and the third lens (113) may have positive values, and the powers of the second and fourth lenses (112, 114) may have negative values. At least one of the object-side surface and the light source-side surface of the fourth lens (114) may have a free-form surface, i.e., a non-rotationally symmetrical surface. The fourth lens (114) may be an aspherical lens closest to the light source (116). By using a lens surface having an aspherical surface, aberrations such as spherical aberration and chromatic aberration can be improved.

[0090]

[0091] The center thicknesses of the first to fourth lenses (111 to 114) are represented by CT1 to CT4, the edge thicknesses at the ends of the effective areas of each lens are represented by ET1 to ET4, and the center gap between two adjacent lenses is represented by CG1 to CG3. The first to fourth lenses (111 to 114) may satisfy at least one of the following conditions.

[0092] Condition 1: CT1 < CT3 < CT2 Condition 2: CT1 < CT4 < CT3

[0093] Condition 3: (CT3-CT4) < (CT2-CT1) Condition 4: ET3 < ET1 < ET2

[0094] Condition 5: ET1 < ET4 < ET2 Condition 6: ET4 < ET2 < CT3 < CT2

[0095] Condition 7: CG1 < CT1 < CT4 < CG2 Condition 8: CG3 < ET2 < CT2 < CG2

[0096] Condition 9: CG1+CG3 < CG2

[0097] The center thickness (CT2) of the second lens (112) is the largest among the lenses, and the center thickness (CT1) of the first lens (111) is the smallest among the lenses. The maximum center thickness may be 1 mm or more thicker than the minimum center thickness. That is, the lenses made of spherical materials are provided with a thick center thickness, thereby reducing the total number of lenses, preventing a deterioration in optical performance by arranging aspherical lenses, and providing a slim sensor system size (light source height).

[0098] Since the aperture (ST) and diffuser (119) are arranged on the object side of the first lens (111), the center thickness of the first lens (111) is thinner than that of the second lens (112), and the radius of curvature is provided to be larger than that of the second lens (112), so that light incident through the second lens (112) can be refracted toward the diffuser (119).

[0099]

[0100] Regarding the center spacing (CG) between adjacent lenses, the center spacing (CG2) between the second lens (112) and the third lens (113) is maximum, and the center spacing (CG3) between the third and fourth lenses (113, 114) is minimum. Here, the difference between the maximum center spacing and the minimum center spacing may be 5 mm or more, for example, in the range of 5 mm to 8 mm. 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 aspherical lens and the spherical lens can be provided. In addition, since the maximum center spacing between the lenses is provided to be greater than the minimum center thickness of each lens, the optical path can be controlled.

[0101] Among the first to fourth lenses (111-114), the maximum distance between adjacent lenses is CGmax, and among the first to fourth lenses (111-114), the minimum distance between adjacent lenses is CGmin, and the mathematical expression: 12 < CGmax / CGmin < 18 can be satisfied.

[0102] In addition, since the center distance (CG2) between the second lens (112) and the third lens (113) is increased, the effective diameters of the first and second lenses (111, 112) can be provided to be smaller than the effective diameter of the third lens (113). The effective diameter of the third lens (113) can be the largest among the lenses. In addition, since the radius of curvature of the third lens (113) is the largest among the lenses, the light incident through the fourth lens (114) can be refracted to the second lens (112) without loss. The lens having the maximum effective diameter can be a spherical lens made of glass, i.e., the third lens (113). The lens surface having the maximum effective diameter can be the fifth surface (S5) of the third lens (113). The lens having the minimum effective diameter can be the first lens (111) adjacent to the aperture (ST). The lens surface having the minimum effective diameter may be the eighth surface (S8) of the fourth lens (114). The effective diameter of each of the first to fourth lenses (111-114) may be greater than the diagonal length of the light source (116). The fourth lens (114) has an aspherical surface and can guide the incident light to the spherical lens.

[0103]

[0104] FIG. 4 is an example of lens data of the transmission optical system of the embodiment of FIG. 1. As shown in FIG. 4, the radius of curvature of the optical axis (OA), the center thickness (CT) of the lenses, the center spacing (CG) between the lenses, the refractive index at the d-line, the Abbe's number, and the size of the effective radius of the first to fourth lenses (111, 112, 113, and 114) can be set. As shown in FIG. 5, among the lenses of the embodiment, the lens surface of the fourth lens (114) may include an aspherical surface having a conic constant (K) and a 14th-order aspherical coefficient (A to F). For example, the object-side surface and the light source-side surface of the fourth lens (114) may be lens surfaces having a 14th-order aspherical coefficient. As described above, an aspherical surface with a 14th aspherical coefficient (a non-zero value) can significantly change the aspherical shape of the periphery, and thus can provide good optical performance correction in the periphery of the field of view (FOV).

[0105]

[0106] The focal lengths (F1, F3) of the first and third lenses (111, 113) may have positive refractive power, and the focal lengths (F2, F4) of the second and fourth lenses (112, 114) may have negative refractive power. In addition, the second lens (112) and the third lens (113), which are adjacently arranged lenses, may satisfy the following conditions.

[0107] Condition 1: Refractive index of lens with positive refractive power < refractive index of lens with negative refractive power

[0108] Condition 2: Dispersion of a lens with positive refractive power > Dispersion of a lens with negative refractive power

[0109] Here, among the lenses, the second lens (112) has negative refractive power and the third lens (113) has positive refractive power, so that the dispersion values ​​of the second and third lenses can be adjusted according to the conditions 1 and 2.

[0110] When comparing the focal lengths in absolute values, the focal length of the fourth lens (114) is the largest among the lenses and can be 150 or more. Accordingly, the optical system can have improved MTF characteristics, aberration control characteristics, etc. in the set angle of view range, and can have good optical performance.

[0111]

[0112] Fig. 6 is a graph showing the diffraction MTF (Modulation Transfer Function) at low, room, and high temperatures in the transmission optical system of Fig. 1, and is a graph showing the modulation ratio according to the spatial frequency. As shown in Fig. 6, in an embodiment of the invention, the deviation of the MTF at low or high temperature with respect to room temperature may be less than 10%, that is, 7% or less. Here, each MTF curve was measured from 0.000 mm to 3.946 mm in units of 0.380 mm.

[0113] FIGS. 7 to 9 are graphs showing aberration characteristics at low temperatures, room temperatures, and high temperatures in the transmission optical system of FIG. 1. In the aberration graphs of FIGS. 7 to 9, spherical aberration (longitudinal spherical aberration), astigmatic field curves, and distortion are measured from left to right. In FIGS. 7 to 9, the X-axis may represent a focal length (mm) and a degree of distortion (%), and the Y-axis may represent a light source height (height). In addition, the graph for spherical aberration is a graph for light in 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 wavelength bands of about 940 nm. In the aberration diagrams of FIGS. 7 to 9, the closer each curve at low temperatures, room temperatures, and high temperatures is to the Y-axis, the better the aberration correction function can be interpreted. Here, the low temperature is -20 degrees or lower, for example, in the range of -20 to -50 degrees, the room temperature is in the range of 22 degrees ± 5 degrees or in the range of 18 to 27 degrees, and the high temperature is 85 degrees or higher, for example, in the range of 85 to 120 degrees. Accordingly, it can be seen that the decrease in the luminance ratio (modulation) from the low temperature to the high temperature in FIGS. 7 to 9 is less than 10%, for example, 5% or lower, or is almost unchanged.

[0114]

[0115] Optical systems experience chromatic aberration, which is corrected using spaced aspherical lenses. As temperatures change from low to high, the lenses contract and expand repeatedly. Since lenses made of the same material exhibit the same degree of change in lens characteristics with temperature, it is effective to compensate for chromatic aberration between lenses made of the same material, even when temperatures change. For example, as shown in Table 1, when the temperature of the lens barrel or receiving optical system changes from -45°C (low temperature), 22°C (room temperature), and 90°C (high temperature), there is little change in optical characteristics. Table 1 compares changes in optical characteristics such as EFL, BFL, F number (F#), TTL, and field of view (FOV) at room temperature, low temperature, and high temperature in an optical system according to an embodiment, and it can be seen that the change rate of optical characteristics at low temperature is 5% or less, for example, 3% or less or 2% or less, based on room temperature, and the change rate of optical characteristics at high temperature is 5% or less, for example, 3% or less or 2% or less, based on room temperature.

[0116] Low temperature Room temperature High temperature Low temperature / Room temperature (%) High temperature / Room temperature (%) EFL 15.276 15.285 15.296 99.94% 100.07% BFL 6.1166 1256 135 99.85% 100.16% FNO 1.575 1.5761.57 899.94% 100.13% TTL 36.96 237 000 37 038 99.90% 100.10% FOV 32.140 32.130 32.100 100.03% 99.91%

[0117] Therefore, as shown in Table 1, it can be seen that the change in optical characteristics according to the temperature change from low temperature to high temperature, for example, the change rate of effective focal length (EFL), TTL, BFL, F number, and field of view (FOV), is 10% or less, that is, 5% or less, for example, in the range of 0 to 5%. This means that even if at least one aspherical lens is used, the design enables temperature compensation for the aspherical lens, thereby preventing a decrease in the reliability of the optical characteristics. The transmission optical system of the embodiment disclosed above can effectively control aberration characteristics such as chromatic aberration and distortion aberration, and can have good optical performance at the center and periphery of the field of view (FOV). Here, EFL is the effective focal length of the receiving optical system, BFL is the optical axis distance from the last lens, i.e., the fourth lens (104) to the surface of the light source (116), Fno is the F number of the optical system, TTL is the optical axis distance from the first lens (111) to the surface of the light source (116), and FOV is the angle of view of the receiving optical system.

[0118] Referring to FIG. 10, the transmitting optical system (110) may have a distortion characteristic set in comparison with a design standard (comparative example) as it goes from a 0 degree field of view to a maximum half field of view (Half FOV). For example, it can be seen that the embodiment of the optical system (110) further increases as the light source height increases as it goes from a 0 degree field of view to a maximum half field of view, and may have a distortion characteristic that satisfies compared to other examples of mapping such as Stereographic, equidistance, rectilinear, and Equisolid. In detail, the embodiment may satisfy the distortion characteristic as compared to the other example 1. In addition, the receiving optical system (110) may have a distortion characteristic set in comparison with other examples as it goes from a 0 degree field of view to a maximum half field of view, thereby providing an optical system that satisfies an Orthographic projection type. Here, the ratio for the distortion characteristic may mean the value of the light source height at a specific half-angle position, calculated as ((Other Example - Example) / Example*100). Accordingly, the optical system according to the embodiment can prevent the optical characteristics from changing due to temperature change in a temperature range from low temperature (-40 degrees) to high temperature (120 degrees) based on the Equal Area mapping method, and can have improved optical performance in various temperature ranges.

[0119]

[0120] According to an embodiment of the invention, a transmission optical system can prevent degradation of optical performance from low to high temperatures by considering the characteristics of a vehicle optical system. For example, after designing a lens at room temperature, the value of the dn / dt, which is a temperature-dependent refractive index change coefficient, is assembled by considering the power combination of each lens, and the value of the temperature coefficient (dn / dt) according to the refractive index of the lens and the defocus for the thickness variable according to low, room, and high temperatures can be set to 5 ㎛ or less. For this purpose, the first to third lenses (111, 112, and 113) are made of a spherical glass material, and the fourth lens (114) is made of an aspherical glass material.

[0121] The transmission optical system (110) according to the embodiment disclosed above can satisfy at least one or two or more of the mathematical equations described below. Accordingly, the optical system (110) according to the embodiment can have improved optical characteristics. For example, when the optical system (110) satisfies at least one mathematical equation, the optical system (110) can effectively control aberration characteristics such as chromatic aberration and distortion aberration, and can have good optical performance even in the center and periphery of the field of view (FOV). In addition, the optical system (110) can have improved resolution. In addition, the thickness of the lens on the optical axis (OA) described in the mathematical equations and the spacing between adjacent lenses on the optical axis (OA) may refer to the embodiment disclosed above.

[0122] [Mathematical Formula 1] 0 < CT1 / CT2 < 3

[0123] CT1 is the central thickness of the first lens (111), and CT2 is the central thickness of the second lens. By setting the central thickness (CT1) of the first lens (111) and the central thickness (CT2) of the second lens (112) in mathematical expression 1, it is possible to prevent a decrease in the rigidity of the first lens (111) and control factors affecting aberration. Preferably, mathematical expression 1 can satisfy 0 < CT1 / CT2 < 1.

[0124] [Equation 2] 0 < CT4 / CT3 < 1

[0125] CT3 and CT4 are the central thicknesses of the third and fourth lenses (113 and 114). By setting the central thicknesses of the third and fourth lenses (113 and 114) in Equation 2, it is possible to prevent the rigidity and optical characteristics of the glass lens from deteriorating, and to control factors affecting aberration. Preferably, Equation 2 can satisfy 0 < CT4 / CT3 < 0.6.

[0126] [Mathematical Formula 3] 0 < CT2 / CT3 < 3

[0127] In mathematical expression 3, the central thicknesses of the second and third (112, 113) can be set, thereby optimizing thermal compensation according to temperature changes from low to high temperatures and preventing degradation of optical performance. Preferably, mathematical expression 3 can satisfy 1 < CT2 / CT3 < 1.5.

[0128] [Mathematical Formula 4] 1 < CG2 / CT2 < 3

[0129] CG2 is the center spacing between the second and third lenses (112, 113). In mathematical expression 4, by setting the center spacing between the second and third lenses (112, 113) to the above range, light refracted through the aspherical fourth lens (114) can be guided along the spacing (CG3) between the second and third lenses (112, 113). Preferably, mathematical expression 4 can satisfy 1 < CG2 / CT2 < 2.

[0130] [Equation 5] 0 < CG2 / (CT3+CT4) < 1

[0131] In mathematical expression 5, the center distance (CG2) between the second and third lenses (112, 113) is set to be smaller than the sum of the center thicknesses (CT3, CT4) of the third and fourth lenses (113, 114), thereby preventing an increase in the effective diameter of the second lens (112). In addition, the effective diameter of the second lens (112) can be adjusted by the effective diameter of the third lens (113) and the distance (CG2).

[0132] [Equation 6] 1 < CG2 / CG1 < 3

[0133] CG1 is the center spacing between the first and second lenses (111, 112). In mathematical expression 6, the center spacing (CG1) between the first and second lenses (111, 112) and the center spacing (CG2) between the second and third lenses (112, 113) can be set to set the center spacing between the spherical lenses. Preferably, 2 < CG1 / CG2 < 2.7 can be satisfied.

[0134] [Equation 7] 5 < CG2 / CG3 < 20

[0135] In mathematical expression 7, the center spacing (CG2) between the second and third lenses (112, 113) is set to be greater than the center spacing (CG3) between the third and fourth lenses (113, 114), so that the center spacing between the spherical lenses and the aspherical lenses can be reduced more than the center spacing between the object-side spherical lenses. Preferably, 10 < CG2 / CG3 < 20 can be satisfied.

[0136] [Equation 8] 0 < CG2 / (CT1+CG1+CT2) < 1

[0137] In mathematical expression 8, the center distance (CG2) between the second and third lenses (112, 113) can be set to be smaller than the optical axis distance between the object-side surface of the first lens (111) and the light source-side surface of the second lens (112). Accordingly, the effective diameter of the object-side surface of the first lens (111) can be set to be smaller than the effective diameter of the object-side surface of the second lens (102), and the second lens (112) can be set to have a convex meniscus shape toward the light source (116). Preferably, 0.3 < CG2 / (CT1+CG1+CT2) < 0.7 can be satisfied.

[0138] [Equation 9] TTL < SD

[0139] SD is the optical axis distance from the aperture (ST) to the surface of the light source (116), and TTL is the optical axis distance from the object-side surface of the first lens to the surface of the light source. Preferably, 1 < SD / TTL < 1.5 can be satisfied, and more preferably, 1 < SD / TTL < 1.2 can be satisfied. When the optical system satisfies mathematical expression 9, the aperture (ST) can be positioned at the farthest position from the light source (116), that is, closer to the object than the first lens (111), thereby controlling the amount of light emitted.

[0140] [Equation 10] 1.70 < Nd1

[0141] Nd1 is the refractive index at the d-line of the first lens (111). In Equation 10, by setting the refractive index of the first lens (111) high, the factor affecting the reduction of the third-order aberration (Seidel aberration) of the optical system can be adjusted, and the aberration that may occur as the TTL becomes somewhat longer can be reduced. Equation 10 can preferably satisfy 1.75 < Nd1 < 2.0. If it is designed to be lower than the lower limit of Equation 10, the performance of reducing aberration can be obtained, and the refractive power of the first lens may be weakened so that light cannot be collected efficiently, which may deteriorate the performance of the optical system. If it is designed to be higher than the upper limit of Equation 10, there is a disadvantage in that it becomes difficult to obtain materials. In addition, if the refractive index of the first lens (111) is designed to be lower than the lower limit of Equation 4, the radius of curvature of the first and second lenses may be increased in order to increase the refractive power of the first and second lenses.

[0142] [Equation 10-1] 1.7 < Aver(Nd1:Nd4) < 1.8

[0143] Aver(Nd1:Nd4) is the average of the refractive index values ​​at the d-line of the first to fourth lenses. When mathematical expression 10-1 is satisfied, the optical system (110) can suppress the influence of TTL.

[0144] [Equation 10-2] GMn_Aver < GLn_Aver

[0145] GLn_Aver is the average of the refractive index values ​​at the d-line of the spherical glass lenses, and GMn_Aver is the average of the refractive index values ​​at the d-line of the aspherical glass lenses. The spherical lens is a lens made of a glass material that is not injection-molded, and the aspherical lens is a lens made of a glass material in a glass mold. Spherical lenses with high refractive index are positioned on the object side of the aspherical lens to increase chromatic dispersion.

[0146] [Equation 11] 0.5 < Nd1 / Nd3 < 1.5

[0147] Nd1 and Nd3 are the refractive indices of the first and third lenses (111 and 113) at the d-line. In Equation 11, the difference in the refractive index of the first lens (111) and the refractive index of the third lens (113) can be reduced, thereby preventing the reduction in color dispersion caused by lenses made of glass. Preferably, the refractive indices of the first, second, and third lenses can be the same.

[0148] [Equation 12] 1 < Nd3 / Nd4 < 1.5

[0149] Nd3 and Nd4 are the refractive indices of the third and fourth lenses (113 and 114) at the d-line. In Equation 12, by setting the refractive index of the third lens (113) higher than the refractive index of the fourth lens (114), the color dispersion caused by the spherical material lenses and the color dispersion caused by the aspherical lenses can be controlled. Preferably, Equation 12 can satisfy 1 < Nd3 / Nd4 < 1.2.

[0150] [Mathematical Formula 13] (Vd1*Nd1) < (Vd4*Nd4)

[0151] Nd1 and Nd4 are the refractive indices of the first and fourth lenses (111 and 114) at the d-line, and Vd1 and Vd4 are the Abbe numbers of the first and fourth lenses. In mathematical expression 13, by setting the product of the refractive index and Abbe number of the first lens (111) to be smaller than the product of the refractive index and Abbe number of the fourth lens (114), the color dispersion by the spherical material lenses and the color dispersion by the aspherical lenses can be controlled.

[0152]

[0153] [Equation 14] TD < SD

[0154] SD is the optical axis distance from the aperture (ST) to the surface of the light source (116), and TD is the optical axis distance from the object-side surface of the first lens (111) to the light source-side surface of the fourth lens (114). When the optical system satisfies mathematical expression 14, the aperture (ST) may be located on the object side relative to the first lens (111).

[0155] [Equation 14-1] TD < TTL < SD

[0156] SD is the optical axis distance from the object-side surface of the first lens (111) to the light source (116). When this mathematical expression 14-1 is satisfied, the position of the aperture (ST) can be set to be located on the object side relative to the first lens (111).

[0157] [Equation 15] 1 < CA42 < CT4 < 3

[0158] CA42 is the effective diameter of the fourth lens (1140) on the light source side, and CT4 is the central thickness of the fourth lens. If mathematical expression 15 is satisfied, the effective diameter of the last lens can be set not to be large compared to the central thickness. Preferably, 1.5 < CA42 < CT4 < 2.5 can be satisfied.

[0159] [Equation 16] CA42 / 2 < CG2 < CA11

[0160] CA11 is the effective diameter of the object-side surface of the first lens. If mathematical expression 16 is satisfied, the center spacing between the second and third lenses can be increased, and the effective diameter of the fourth lens can be set not to increase.

[0161] [Mathematical Formula 17] 0.5 < CA11 < (CG1+CG2) < 1.5

[0162] In mathematical expression 17, the effective diameter (CA11) of the object-side surface of the first lens, the center distance (CG1) between the first and second lenses, and the center distance (CG2) between the second and third lenses can be set, and if these are satisfied, the number of lenses of the spherical lenses can be reduced. Preferably, 1 < CA11 < (CG1+CG2) < 1.2 can be satisfied.

[0163] [Equation 18] 0.5 < CA11 / CA21 < 1.5

[0164] CA11 refers to the effective diameter of the first surface (S1) of the first lens (111), and CA21 refers to the effective diameter of the third surface (S3) of the second lens (112). When mathematical expression 18 is satisfied, the optical system (110) can control the emitted light and set factors affecting aberration, and preferably, CA11 > CA21 can be satisfied.

[0165] [Equation 19] 0.4 < CA22 / CA31 < 1.5

[0166] CA22 refers to the effective diameter of the fourth surface (S4) of the second lens (112), and CA31 refers to the effective diameter of the fifth surface (S5) of the third lens (113). When mathematical expression 19 is satisfied, the optical system (110) can control the light path to be emitted, and can set the light source-side surface of the second lens (112) to a convex shape. Preferably, mathematical expression 19 can satisfy 0.6 < CA22 / CA31 < 1.

[0167] [Equation 19-1] 0.8 < (CA11+CA31) / (CA21+CA41) < 1.2

[0168] CA41 refers to the effective diameter of the object-side surface (S7) of the fourth lens (114). When mathematical expression 19-1 is satisfied, the optical system (110) can set the light path to be emitted, for example, the light path of the first to fourth lenses (111-114).

[0169] [Equation 20] 0.5 < CA11 / ST_CA < 1.5

[0170] CA11 denotes the effective diameter of the first surface (S1) of the first lens (111), and ST_CA denotes the effective diameter of the aperture (ST). When mathematical expression 20 is satisfied, the optical system (110) can set a light path that is emitted toward the aperture (ST) through the first lens (111). Mathematical expression 20 can preferably satisfy 1 < CA11 / ST_CA < 1.3.

[0171] [Equation 21] 1 < CA11 / CG0 < 5

[0172] CA11 denotes the effective diameter of the first surface (S1) of the first lens (111), and CG0 is the optical axis distance between the first lens (111) and the aperture (ST) or diffuser (119). When the optical system (110) satisfies mathematical expression 21, the effective diameter and radius of curvature of the first lens (111) can be adjusted. Mathematical expression 21 can preferably satisfy 3 < CA11 / CG0 < 4.

[0173] [Equation 22] 0.5 < CG0 / CT1 < 1.5

[0174] When the optical system satisfies mathematical expression 22, the optical axis distance between the first lens (111) and the aperture (ST) or diffuser (119) and the central thickness of the first lens (111) can be set, and distortion aberration can be controlled. Preferably, 0.5 < CG0 / CT1 < 1 can be satisfied.

[0175] [Equation 23] 0 < ST_CA / CA_Min < 1

[0176] CA_Min represents the smallest effective diameter among the lens surfaces of the lenses. If the optical system satisfies Equation 23, the entire optical axis length can be controlled. Preferably, 0.5 < ST_CA / CA_Max < 1 can be satisfied.

[0177] [Equation 24] 1 < CG_Max / CG0 < 4

[0178] CG_Max refers to the maximum center spacing between lenses in the optical system. When the optical system satisfies mathematical expression 24, the maximum center spacing between lenses can set the relationship between the optical axis spacing between the first lens (111) and the aperture (ST) or diffuser (119), thereby adjusting the overall optical axis length and suppressing an increase in the effective diameter of the first lens (111). Preferably, 1.5 < CG_Max / CG0 < 3 or 1.5 < CG2 / CG0 < 3 can be satisfied.

[0179] [Equation 25] 0.5 < CT4 / BFL < 1.5

[0180] CT4 is the central thickness of the fourth lens, and BFL is the optical axis distance from the center of the light source-side surface of the last lens to the light source (116). That is, BFL is the optical axis distance from the center of the eighth surface (S8) of the fourth lens (114) to the light source (116). When mathematical expression 25 is satisfied, the emitted light can be transmitted to the entire area of ​​the third lens (103) by the fourth lens (114). Preferably, 0.5 < CT4 / BFL < 1 can be satisfied.

[0181] [Equation 26] 0 < CG3 / CT4 < 1

[0182] CG3 represents the center spacing between the third and fourth lenses, and CT4 represents the center thickness of the fourth lens. When mathematical expression 26 is satisfied, the center spacing between the third and fourth lenses (113, 114) can be narrowed, and the effective diameter of the fourth lens (114) can be adjusted. Preferably, 0 < CG3 / CT4 < 0.3 can be satisfied.

[0183] [Equation 27] 2 < ST_CA / CG0 < 4

[0184] When the transmitting optical system satisfies mathematical expression 27, the position of the diffuser (119) can be set, and due to the diffuser (119), the transmitting optical system and the receiving optical system can be optically matched even if they provide different aspect ratios. Preferably, 2.5 < ST_CA / CG0 < 3.5 can be satisfied.

[0185]

[0186] [Equation 28] 1 < L4R2 / CT4 < 5

[0187] L4R2 is the radius of curvature of the light source side surface of the fourth lens. When mathematical expression 28 is satisfied, the refractive power of the fourth lens (114) can be controlled and optical performance can be improved. Preferably, 1 < L4R2 / CT4 < 2 can be satisfied.

[0188] [Equation 29] 0.5 < L4R2 / L4R1 < 1.5

[0189] L4R1 is the radius of curvature of the object-side surface of the fourth lens. When mathematical expression 29 is satisfied, the refractive power of the fourth lens (114) can be controlled and optical performance can be improved. Preferably, 0.5 < L4R2 / L4R1 < 1 can be satisfied.

[0190] [Mathematical Formula 30] 0 < L1R1 / L1R2 < 3

[0191] L1R1 is the radius of curvature of the object-side surface of the first lens, and L1R2 is the radius of curvature of the light source-side surface of the first lens. When mathematical expression 30 is satisfied, the refractive power of the first lens (111) can be controlled and the optical performance can be improved. Preferably, 0 < L1R1 / L1R2 < 1 is satisfied, and in this case, the distance between the first lens (111) and the aperture (ST) or diffuser (119) can be set. In addition, L1R1 > 0 and L1R2 > 0 may be satisfied.

[0192] [Equation 31] 0.5 < |L2R1 / L2R2| < 1.5

[0193] L2R1 is the radius of curvature of the object-side surface of the second lens, and L2R2 is the radius of curvature of the light source-side surface of the second lens. When mathematical expression 31 is satisfied, the refractive power of the second lens (112) can be controlled to improve optical performance, and the incidence efficiency through the light source-side surface of the second lens (112) can be improved. Preferably, 0.5 < |L2R1 / L2R2| < 1 is satisfied, and L2R1 < 0 and L2R2 < 0 can be satisfied.

[0194] [Equation 31-1] 2 < L3R2 / L3R1 < 6

[0195] L3R1 is the radius of curvature of the object-side surface of the third lens, and L3R2 is the radius of curvature of the light source-side surface of the third lens. When mathematical expression 31-1 is satisfied, the refractive power of the third lens (113) can be controlled and the optical performance can be improved, and light can be refracted into the effective area of ​​the second lens (112) through the object-side surface of the third lens (113). Preferably, 3 < L3R2 / L3R1 < 5.5 is satisfied, and L3R1 > 0 and L3R2 > 0 can be satisfied.

[0196] [Equation 32] 0 < CT_Max / CG_Max < 2

[0197] In Equation 32, the maximum central thickness (CT_Max) among the lenses and the maximum gap (CT_Max) between adjacent lenses can be set. When Equation 32 is satisfied, the optical system can have good optical performance at the focal length of the set angle of view and can reduce TTL. Preferably, 0.5 < CT_Max / CG_Max < 1 can be satisfied.

[0198] [Equation 33] 1 < ΣCT / ΣCG < 3

[0199] 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 33 is satisfied, the optical system can have good optical performance at the focal length at the set angle of view, and can reduce the TTL. Preferably, 1.5 < ΣCT / ΣCG < 2 can be satisfied.

[0200] [Equation 34] 5 < ΣNd < 15

[0201] ΣNd represents the sum of the refractive indices at the d-line of each of the plurality of lenses. When mathematical expression 34 is satisfied, TTL can be controlled in an optical system (110) in which aspherical lenses and spherical lenses are mixed. In addition, when the number of spherical lenses is greater than the number of aspherical lenses, the sum of TTL and refractive indices can be set. Mathematical expression 34 can preferably satisfy 6 ≤ ΣNd ≤ 10.

[0202] [Equation 35] 10 < ΣVd / ΣNd < 50

[0203] ΣVd means the sum of the Abbe numbers of each of the plurality of lenses. When mathematical expression 35 is satisfied, the optical system (110) can have improved aberration characteristics and resolution. By setting the sum of the Abbe numbers and the sum of the refractive indices of the lenses in mathematical expression 35, the optical characteristics can be controlled, and preferably, 13 < ΣVd / ΣNd < 23 can be satisfied.

[0204] [Equation 36] 50 < ΣCT*n < 100

[0205] ΣCT is the sum of the central thicknesses of multiple lenses, and n is the number of lenses in the optical system. If mathematical expression 36 is satisfied, TTL can be controlled. Preferably, 70 < ΣCT*n < 90 can be satisfied.

[0206] [Equation 37] 0 < ΣCT / ΣET < 2

[0207] ΣCT is the sum of the central thicknesses of the lenses, and ΣET is the sum of the edge thicknesses, that is, the ends of the effective areas of the lenses. When mathematical expression 37 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. Mathematical expression 37 can preferably satisfy 1 < ΣCT / ΣET < 1.6.

[0208] [Equation 38] 1 < CA11 / CA_Min < 5

[0209] CA11 is the effective diameter of the object-side first surface (S1) of the first lens, and CA_Min represents the minimum effective diameter among the object-side surfaces and the light source-side surfaces of the lenses. When mathematical expression 38 is satisfied, the optical system can control incident light, maintain optical performance, and provide a slimmer module. Mathematical expression 38 can preferably satisfy 1 < CA11 / CA_Min < 3. Here, CA42 may be the minimum effective diameter among the lens surfaces.

[0210] [Equation 38-1] 1 < CA_Max / CA_Min < 5

[0211] CA_Max represents the maximum effective diameter between the object-side and light-source-side surfaces of the lenses. When mathematical expression 39 is satisfied, the optical system can be sized for a slim and compact structure while maintaining optical performance. Mathematical expression 39 can preferably satisfy 1 < CA_Max / CA_Min < 3 or 1.5 < CA_Max / CA_Min < 2.

[0212] [Equation 39] 0 < CG2 / CA12 < 1

[0213] CG2 is the center distance between the second and third lenses, and CA12 is the effective diameter of the light source-side surface of the first lens. If mathematical expression 39 is satisfied, the incident light of the spherical lenses can be controlled. Mathematical expression 39 preferably satisfies 0.3 < CG2 / CA12 < 0.9.

[0214] [Mathematical Formula 40] 1 < CA_Max / CA_Aver < 3

[0215] CA_Aver represents the average effective diameter of the object-side and light-source-side surfaces of the lenses. When Equation 40 is satisfied, the optical system can maintain optical performance while establishing a slim and compact sensor device. Equation 40 preferably satisfies 1 < CA_Max / CA_Aver < 2.

[0216] [Equation 41] 0.1 < CA_Min / CA_Aver < 2

[0217] When mathematical expression 41 is satisfied, the optical system can establish a slim and compact sensor device while maintaining optical performance. Mathematical expression 41 preferably satisfies 0.5 < CA_Min / CA_Aver < 1.

[0218] [Equation 42] 1 < CA_Max / (2*LsH) < 6

[0219] Mathematical expression 42 can be set to the maximum effective diameter (CA_Max) and the diagonal length of the light source (2*LsH). If this is satisfied, the optical system can maintain good optical performance and a slim and compact sensor device can be set. Mathematical expression 42 preferably satisfies 1 < CA_max / (2*LsH) < 3.

[0220] [Equation 42-1] 1 < TD / CA_Max < 4

[0221] TD is the optical axis distance from the center of the object-side surface of the first lens to the center of the light-source-side surface of the last lens. When mathematical expression 42-1 is satisfied, the total optical axis distance and maximum effective diameter of the lenses can be set, and thus the size for good optical performance can be set. Mathematical expression 42-1 can preferably satisfy 1 < TD / CA_Max < 3.

[0222]

[0223] [Equation 43] 0 < F / L4R2 < 3

[0224] F is the effective focal length of the transmitting optical system, and L4S2 is the radius of curvature of the light source-side surface of the fourth lens. If Equation 43 is satisfied, the effect on optical system reduction, such as TTL, can be controlled by setting the effective focal length and the radius of curvature of the light source-side surface of the last aspherical lens. Equation 43 can preferably satisfy 1 < F / L4R2 < 3.

[0225] [Equation 44] 0 < F / L1R1 < 2

[0226] In mathematical expression 44, the effective focal length of the transmitting optical system and the radius of curvature of the object-side surface of the first lens can be set to control the influence on the output light and TTL. Mathematical expression 44 can preferably satisfy 0.5 < F / L1R1 < 1.

[0227] [Equation 45] 0 < EPD / L4R2 < 2

[0228] EPD refers to the size (mm) of the entrance pupil of the optical system (110), and L4R2 refers to the radius of curvature of the light source-side surface of the fourth lens. When the optical system (110) according to the embodiment satisfies mathematical expression 45, the optical system (110) can control incident light. Preferably, the condition of 1 < EPD / L4R2 < 1.5 can be satisfied. Preferably, L4R1 > 0, L4R2 > 0 can be satisfied.

[0229] [Equation 46] 0 < EPD / L1R1 < 1

[0230] In mathematical expression 46, the size of the entrance pupil of the optical system (110) and the radius of curvature of the object-side surface of the first lens can be set, and when these are satisfied, the optical system (110) can control the emitted light. Preferably, the condition of 0.3 < EPD / L1R1 < 0.8 can be satisfied.

[0231] [Equation 47] 0 < |F1 / F2| < 1

[0232] F1 is the focal length of the first lens, and F2 is the focal length of the second lens. When mathematical expression 47 is satisfied, the refractive power of the first and second lenses can be controlled, and the TTL and effective focal length (EFL) can be influenced. Preferably, 0 < |F1 / F2| < 0.5 can be satisfied. The first and second lenses (111, 112) have powers of opposite signs, so that aberration can be corrected. Here, F1 > 0 and F2 < 0 can be satisfied.

[0233] [Equation 48] 1 < |F1| / F < 10

[0234] In mathematical expression 48, the focal length of the first lens and the effective focal length of the optical system can be set, and the refractive power of the first lens can be controlled.

[0235] [Equation 49] 0 < |F1 / F4| < 10

[0236] In mathematical expression 49, the focal lengths of the first and fourth lenses can be set, and the refractive powers of the first and fourth lenses can be controlled. Preferably, 0 < |F1 / F5| < 0.5 can be satisfied.

[0237] [Mathematical Formula 49-1] F3 < F1 < |F4| (However, F4 < 0)

[0238] [Equation 49-2] |F2| < |F4|

[0239] [Equation 49-3] 5*F1 < |F2|

[0240] [Equation 49-3] 5*F3 < |F4|

[0241] In mathematical expressions 49-1 to 49-4, F1, F2, F3, and F4 represent the focal lengths of the first to fourth lenses, and by adjusting the focal length of the spherical lens to the focal length of the last aspherical lens, light can be guided to the effective area of ​​the spherical lens. The balance of the focal lengths of each of the lenses can suppress the difference in focus position due to temperature change. Accordingly, the optical characteristics of the lenses can be suppressed from deteriorating due to temperature change. In addition, the overall focal length of the transmitting optical system can be greater than the overall focal length of the receiving optical system.

[0242] [Mathematical Formula 50] Po2 * Po3 < 0

[0243] Po2 is the power value of the second lens, and Po3 is the power value of the third lens. That is, the powers of the second and third lenses have opposite signs, which can improve aberrations and effectively guide light through the spherical lens. When the condition of Po2 * Po3 > 0, the improvement effect of chromatic aberration in the two lenses is not significant.

[0244]

[0245] [Mathematical Formula 51] 20mm < TTL < 60mm

[0246] TTL (Total track length) means the distance (mm) from the center of the first surface (S1) of the first lens (111) to the upper surface of the light source (116) on the optical axis (OA). In mathematical expression 51, the TTL may be set to be greater than 20 mm and less than 60 mm, thereby providing a vehicle optical system. Mathematical expression 51 may preferably satisfy the condition of 30 mm < TTL < 55 mm or TD < TTL. In addition, the TTL of the transmitting optical system may be smaller than the TTL of the receiving optical system. In addition, the number of lenses in the transmitting optical system may be smaller than the number of lenses in the receiving optical system. In addition, the number of aspherical lenses in the transmitting optical system may be smaller than the number of aspherical lenses in the receiving optical system.

[0247] [Mathematical Formula 52] 2mm < LsH < 10mm

[0248] LsH is half the diagonal length of the light source. Mathematical expression 52 can set the diagonal size (2*LsH) of the light source (116) and provide an optical system having a vehicle sensor size. Mathematical expression 52 can preferably satisfy 2 mm < LsH < 5 mm.

[0249] [Mathematical Formula 53] 1.5mm < BFL < 9mm

[0250] In mathematical expression 53, the BFL (Back focal length) is set to be greater than 1.5 mm and less than 9 mm, thereby improving the assemblability of components and improving the joint reliability through the gap between the light source (116) and the last lens. Mathematical expression 53 can preferably satisfy 5 mm < BFL < 7 mm. When the BFL is less than the range of mathematical expression 53, 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 53, stray light may be emitted, which may deteriorate the aberration characteristics of the optical system.

[0251] [Mathematical Formula 54] 5mm < F < 30mm

[0252] Mathematical expression 54 can set the overall focal length (F) to suit the vehicle transmitting optical system. Mathematical expression 54 can satisfy 10 mm < F < 20 mm, and can be greater than the overall focal length of the receiving optical system.

[0253] [Mathematical Formula 55] FOV < 80 degrees

[0254] In mathematical expression 55, 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) of less than 80 degrees can be provided. The FOV can preferably satisfy 30 ≤ FOV ≤ 60. The angle of view of the transmitting optical system can be provided narrower than the angle of view of the receiving optical system. That is, even if the angle of view of the receiving optical system is implemented wide by the diffuser (119), the sensitivity of the detection unit can be prevented from decreasing. In mathematical expression 55, the range of the vehicle optical system can be set by the angle of view. When mathematical expression 55 is satisfied, the rate of change of the effective focal length and the rate of change of 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%. In addition, even if an aspherical lens is used in combination with a spherical lens within the optical system (110), the deterioration of optical characteristics can be prevented through temperature compensation and aberration correction by the aspherical lens made of glass.

[0255] [Equation 56] 1 < TTL / CA_Max < 7

[0256] In mathematical expression 56, CA_Max means the largest effective diameter (mm) among the object-side and light-source-side surfaces of the plurality of lenses, and TTL (Total track length) means the distance (mm) from the vertex of the first surface (S1) of the first lens to the upper surface of the light source (116) on the optical axis (OA). Mathematical expression 56 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 56 can preferably satisfy 1 < TTL / CA_Max < 3.

[0257] [Mathematical Formula 57] 5 < TTL / LsH < 15

[0258] Mathematical expression 57 can set the total optical axis length (TTL) of the optical system and the diagonal length (LsH) from the optical axis of the light source (116). When the optical system (110) according to the embodiment satisfies Mathematical expression 57, the optical system (110) can have TTL for application to the vehicle light source (116), thereby providing improved image quality. Mathematical expression 57 can preferably satisfy 5 < TTL / LsH < 11.

[0259] [Equation 58] 0 < BFL / LsH < 3

[0260] Mathematical expression 58 can set the optical axis distance between the light source (116) and the last lens and the length in the diagonal direction from the optical axis of the light source (116). When the optical system (110) according to the embodiment satisfies Mathematical expression 58, the optical system (110) can secure a BFL (Back focal length) for applying the size of the vehicle light source (116), can set the distance between the last lens and the light source (116), and can have good optical characteristics in the field of view (FOV). Mathematical expression 58 can preferably satisfy 1 < BFL / LsH < 2.

[0261] [Equation 59] 1 < TTL / BFL < 15

[0262] Mathematical expression 59 can set the total optical axis length (TTL) of the optical system and the optical axis spacing (BFL) between the light source (116) and the last lens. When the optical system (110) according to the embodiment satisfies Mathematical expression 59, the optical system (110) can secure BFL. Mathematical expression 59 can preferably satisfy 3 < TTL / BFL < 10.

[0263]

[0264] [Equation 60] 1 < TTL / F < 10

[0265] Mathematical expression 60 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 60 can preferably satisfy 1.5 ≤ TTL / F < 3. When the optical system (110) according to the embodiment satisfies Mathematical expression 60, the optical system (110) can have an appropriate focal length in the set TTL range, and provides an optical system that can form an image while maintaining an appropriate focal length even when the temperature changes from low to high. When it is less than the lower limit of Mathematical expression 60, it is necessary to increase the refractive power of the lenses, making it difficult to correct spherical aberration or distortion aberration, and when it is more than the upper limit of Mathematical expression 60, the effective diameter or TTL of the lenses becomes long, which may cause a problem of a large-sized imaging lens system.

[0266] [Equation 61] 0 < F / BFL < 3

[0267] Mathematical expression 61 can set the total focal length (F) of the optical system (110) and the optical axis distance (BFL) between the light source (116) and the last lens. When the optical system (110) according to the embodiment satisfies Mathematical expression 61, the optical system (110) 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) can minimize the distance between the last lens and the light source (116), and thus can have good optical characteristics in the angle of view (FOV). Mathematical expression 61 can preferably satisfy 1 < F / BFL < 3.

[0268] [Equation 62] 1 < F / LsH < 5

[0269] Mathematical expression 62 can set the total focal length (F, mm) of the optical system (110) and the diagonal length (LsH) from the optical axis of the light source (116). This optical system (110) can have improved aberration characteristics in the size of the vehicle light source (116). Mathematical expression 62 can preferably satisfy 3 < F / LsH < 4.

[0270] [Equation 63] 1 < F / EPD < 3

[0271] Mathematical expression 63 can set the overall focal length (F) and entrance pupil size of the optical system (110). Accordingly, the overall brightness of the optical system can be controlled. Mathematical expression 63 preferably satisfies 1.2 < F / EPD < 2.

[0272] [Equation 64] 0 < EPD / LsH / FOV < 0.2

[0273] Mathematical expression 64 can set the relationship between the entrance pupil size (EPD), the length of half the diagonal length of the light source (LsH), and the field of view. Accordingly, the overall size and brightness of the optical system can be controlled. Mathematical expression 64 can preferably satisfy 0 < EPD / LsH / FOV < 0.1.

[0274] [Equation 65] 10 < FOV / F# < 30

[0275] Mathematical expression 65 can establish the relationship between the angle of view and the F number (F#) of the optical system. Mathematical expression 65 can preferably satisfy 15 < FOV / F# < 25. Here, F# is provided to be 1.8 or less, thereby providing a bright image.

[0276] [Equation 66] 20 < (CT_Max+CG_Max)*n < 80

[0277] [Mathematical Formula 67] 200 < (FOV*TTL) / n < 500

[0278] Preferably, mathematical expression 67 can satisfy the condition of 200 < (FOV*TTL) / n < 400 depending on the angle of view and the number of lenses (n).

[0279] [Mathematical Formula 68] FOV < (TTL*n)

[0280] [Equation 69] 1 < (TD / CA_Max)*n < 20

[0281] Preferably, 1 < (TD / CA_Max)*n < 10 can be satisfied.

[0282] [Mathematical Formula 70] 0 < (CA42 / CA22) / (CA11 / CA22) < 1

[0283] In mathematical expressions 66 to 70, n represents the total number of lenses, and depending on the total number of lenses, the relationship between the maximum center thickness (CT_Max), maximum center spacing (CG_max), FOV, TTL, optical axis distance (TD) of the lenses, effective diameter (CA42) of the light source side surface of the fourth lens, effective diameter (CA11) of the object side surface of the first lens, and effective diameter (CA22) of the light source side surface of the second lens can be set. Accordingly, the chromatic aberration, resolution, size, etc. of an optical system having five or fewer lenses can be controlled.

[0284] [Equation 71]

[0285]

[0286] In mathematical expression 71, Z may represent Sag, which is the distance from any position on the aspherical surface to the vertex of the aspherical surface in the direction of the optical axis. Y may represent the distance from any position on the aspherical surface to the optical axis in the direction perpendicular to the optical axis. c may represent the curvature of the lens, and K may represent the conic constant. In addition, A, B, C, D, E, and F may represent aspheric coefficients.

[0287]

[0288] The optical system (110) according to the embodiment can satisfy at least one or two or more mathematical equations from mathematical equations 1 to 70. In this case, the optical system (110) can have improved optical characteristics. Specifically, when the optical system (110) satisfies at least one of mathematical equations 1 to 35 and / or at least one of mathematical equations 36 to 70, the optical system (110) can have improved resolution and improve aberration and distortion characteristics. In addition, the optical system (110) can secure a BFL (Back focal length) for applying a vehicle light source (116), can compensate for optical characteristic degradation due to temperature change, and can minimize the distance between the last lens and the light source (116), thereby having good optical performance within the field of view (FOV).

[0289]

[0290] Table 2 shows the items of the mathematical formulas described above in the transmission optical system (110) of the embodiment, 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 eighth surface (S8), focal lengths (F1, F2, F3, F4), angle of view (FOV), edge thickness (ET), F number, etc. of each of the first to fourth lenses.

[0291] Item ValueItem ValueF15.285ET13.640F159.114ET25.022F2-424.793ET32.507F321.623ET44.026F4-294.356FOV32.1340ΣNd7.125E PD9.7000ΣVd124.440BFL6.125ΣCT19.750TD30.8747ΣCG11.125LsH4.2300ΣET15.195SD40.1700TTL37.0F-number1.576

[0292] Table 3 shows the result values ​​for the mathematical expressions 1 to 70 described above in the optical system (110) of the embodiment. Referring to Table 4, it can be seen that the transmission optical system (110) satisfies at least one, two or more, or three or more of the mathematical expressions 1 to 35. In addition, it can be seen that the optical system (110) satisfies at least one, two or more, or three or more of the mathematical expressions 36 to 70. In detail, it can be seen that the optical system (110) according to the embodiment satisfies at least one or two or more of the mathematical expressions 1 to 70, or all of the mathematical expressions. Accordingly, the optical system (110) can have good optical performance within the field of view (FOV) and can have excellent optical characteristics.

[0293] Equation ValueEquation Value10 < CT1 / CT2 < 30.7063650 < ∑CT*n < 10079.00020 < CT4 / CT3 < 30.386370 < ΣCT / ΣET < 21.30030 < CT2 / CT3 < 31.055381 < CA11 / CA_Min < 51.82041 < CG2 / CT2 < 31.321390 < CG2 / CA12 < 10.65850 < CG2 / (CT3+CT4) < 10.607401 < CA_Max / CA_Aver < 31.34961 < CG2 / CG1 < 32.332410.1 < CA_Min / CA_Aver < 20.74175 < CG2 / CG3 < 2014.872421 < CA_Max / (2*LsH) < 62.19980 < CG2 / (CT1+CG1+CT2) < 10.581430 < F / L4R2 < 32.0229TTL < SDSatisfied440 < F / L1R1 < 20.893101.70 < Nd1 1.816450 < EPD / L4R2< 21.283110.5 < Nd1 / Nd3 <1.51.000460 < EPD / L1R1 < 10.567121 < Nd1 / Nd4 <1.51.083470 < |F1 / F2| < 10.13913(Vd3*Nd3) < (Vd4*Nd4)Satisfied481 <| F1| / F < 103.86714TD < SD Satisfaction 490 < |F1 / F4| < 100.201151 < CA42 / CT4 < 32.12450Po2 * Po3 < 0Satisfied16CA42 / 2 < CG2 < CA11Satisfied5120 < TTL <6037.000170.5 < CA11 < (CG1+CG2) < 1.51.094522 < LsH <104.230180.5 < CA11 / CA21 < 1.51.009531.5 < BFL < 96.125190.4 < CA22 / CA31 < 1.50.813545 < F < 3015.285200.5 < CA11 / ST_CA < 1.51.19855FOV < 8032.134211 < CA11 / CG0 < 53.666561 < TTL / CA_Max < 71.989220.5 < CG0 / CT1 < 1.50.798575 < TTL / LsH < 158.747230 < ST_CA / CA_Min < 10.949580 < BFL / LsH < 31.448241 < CG_Max / CG0 < 42.346591 < TTL / BFL < 156.041250.5 < CT4 / BFL < 1.50.785601 < TTL / F < 102.421260.5 < CG3 / CT4 < 10.104610 < F / BFL < 32.495272 < ST_CA / CG0 < 43.060621 < F / LsH < 53.613281 < L4R2 / CT4 < 51.571631 < F / EPD < 31.576290.5 < L4R2 / L4R1 < 1.50.765640 < EPD / LsH / FOV < 0.20.071300 < L1R1 / L1R2 < 30.7216510 < FOV / F# <3020.392310.5 < |L2R1 / L2R2| < 1.50.7836620 < (CT_Max+CG_Max)*n < 8052.258320 < CT_Max / CG_Max < 20.75767200 < (FOV*TTL) / n < 500297.240331 < ∑CT / ∑CG < 31.77568FOV < (TTL*n)만족345 < ∑Nd <157.125691 < (TD / CA_Max) *n < 206.6403510 < ∑Vd / ∑Nd <5017.466700 < (CA42 / CA22) / (CA11 / CA21) < 10.670.

[0294]

[0295] <수신 광학계>

[0296] The receiving optical system receives the light emitted from the transmitting optical system disclosed above and converts the received light into an electrical signal. The receiving optical system may have a different number of lenses than the transmitting optical system, for example, four or more or five or more lenses. The receiving optical system and the transmitting optical system may be aligned along their respective optical axes and may have individual optical characteristics.

[0297] Referring to FIG. 11, the receiving optical system (100) 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 sensor-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 sensor-side surface of the lens is aspherical. The receiving optical system (100) may include a spherical glass lens and an aspherical glass lens. In addition, by employing an aspherical lens, the optical system (100) 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 lens may minimize distortion in the periphery of the sensing unit (300). The optical system (100) may include n lenses, and the n-th lens may be the last lens adjacent to the sensing unit (151), and the (n-1)th lens may be the lens closest to the last lens. The above n is an integer greater than or equal to 4, and may be, for example, in the range of 4 to 7 or in the range of 4 to 6. The ratio of the spherical lens to the aspherical lens in the n lenses may be any one of 3:1, 4:1, 3:2, 2:3, 3:3, 5:2, or 4:2.

[0298] In the receiving optical system (100), the first lens (101) closest to the object may be made of glass. The glass material has a small amount of expansion and contraction change due to external temperature changes, and the surface is not easily scratched, thereby preventing surface damage. Accordingly, in the optical system (100), the first lens (101) on the object side may be a spherical lens, and the nth lens may be arranged as an aspherical lens. Since the nth lens in the optical system (100) is arranged as an aspherical lens, various aberrations for the light incident on the sensing unit (151) may be corrected. Since at least two lenses closest to the object in the optical system (100) are arranged of glass, the rate of contraction and expansion change due to temperature change is smaller than that of plastic materials, thereby preventing deterioration of optical characteristics due to temperature change within the lens barrel.

[0299] In addition, since the optical system (100) has a lens (105) closest to the sensing unit (151) made of glass mold material, the rate of change in shrinkage and expansion due to temperature change is smaller than that of plastic material, and thus, deterioration of optical characteristics due to temperature change within the lens barrel can be prevented.

[0300] Each of the lenses (101-105) of the receiving optical system may have an object-side surface and a sensor-side surface. The lenses (101-105) may include an object-side spherical lens and a sensor-side spherical lens, and an object-side aspherical lens and a sensor-side aspherical lens. The number of aspherical lenses in the optical system may be smaller than the number of spherical lenses. Since the optical system (100) has aspherical lenses arranged adjacent to the sensing unit (151), it can correct various aberrations. The spherical lenses and aspherical lenses may be made of glass. Among the lenses of the optical system (100), the lens having the highest refractive index may be a spherical lens, and the lens having the highest Abbe number may be a spherical lens. Accordingly, since the lens having the highest refractive index is arranged on the object side, it is easy to change the radius of curvature of the lenses after the second lens, and the central thickness can be increased.

[0301]

[0302] Within the optical system (100), the lens surface having the largest effective diameter is positioned on the first lens (101) closest to the object side, and may be made of glass and may be a spherical lens. Within the optical system (100), the lens having the smallest effective diameter is positioned between the aperture (ST) and the first lens (101), 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 and the effective diameter of the sensor-side surface of each lens. By adjusting the effective diameter of each lens, the optical system (100) may be miniaturized. Each of the lenses (101-105) may include an effective area and an ineffective area. The effective area may be an area through which light incident on each of the lenses passes. That is, the effective area may be defined as an effective area or effective diameter in which the incident light is refracted to implement optical characteristics. The above-mentioned ineffective area may be arranged around the perimeter of the effective area. The ineffective area may be an area where effective light is not incident from the plurality of lenses. In other words, the ineffective area may be an area unrelated to the optical characteristics. In addition, the end of the ineffective area may be an area fixed to a lens barrel (not shown) that accommodates the lens.

[0303]

[0304] Among the lenses of the optical system (100), the lens having the largest center thickness may be a spherical lens, and the lens having the largest edge thickness may be a spherical lens. The average center thickness of the spherical lenses may be greater than the average center thickness of the aspherical lenses. The TTL (Total Top Length) can be reduced by the aspherical lenses having a thin thickness, and the incident light can be refracted into various paths.

[0305] Within the receiving optical system (100), TTL may be more than 10 times, for example, more than 10 times and less than 20 times, than ImgH. The TTL (Total track length) is the distance from the center of the object-side surface of the first lens (101) to the upper surface of the sensing unit (151) on the optical axis (OA). The ImgH is the distance from the center of the effective area of ​​the sensing unit (151) to the diagonal end or half of the maximum diagonal length of the effective area of ​​the sensing unit (151). In addition, the effective diameter of each lens within the optical system (100) may be greater than the diagonal length of the sensing unit (151).

[0306] In the receiving optical system (100), the effective focal length (EFL) is provided to be 10 mm or less and the field of view (FOV) is 60 degrees or more or 100 degrees or more, so that it can be provided as a standard receiving optical system in a vehicle sensor system. For example, the receiving optical system and the sensor system according to the embodiment can be applied to a sensing device for an ADAS (Advanced Driving Assistance System) installed inside or outside a vehicle. The receiving optical system (100) can have a condition of TTL / (2*ImgH) greater than 5, for example, a range greater than 5 and less than 10. Accordingly, the central thickness of each lens along the optical axis (OA) can be increased and the size of the sensing unit (151) can be reduced, so that a vehicle lens optical system can be provided. In addition, in order to be used in a vehicle camera, temperature compensation must be applied in a temperature range that serves as a temperature reliability evaluation standard for automotive electrical components, that is, -45°C to +120°C. That is, the lens must be configured so that the focus of the lens remains within a set range even when the lens expands or contracts due to temperature changes. The lens can be configured with a total effective focal length (EFL) of 10 mm or less, for example, a range of 1 mm to 10 mm or a range of 1 mm to 6 mm, and made of a glass material capable of the aforementioned temperature compensation. By shortening the effective focal length of the optical system, a wide angle can be achieved.

[0307]

[0308] The number of lenses having positive (+) refractive power in the receiving optical system (100) may be equal to or greater than the number of lenses having negative (-) refractive power. The number of lenses having positive (+) refractive power may be 50% or more of the total number of lenses. The average refractive index of the lenses having negative refractive power may be less than the average of the lenses having positive refractive power. The difference between the average refractive index of the lenses having negative refractive power and the average of the lenses having positive refractive power may be 0.5 or less, for example, 0.2 or less. Accordingly, the dispersion value of the lenses having positive refractive power may be greater than the dispersion value of the lenses having negative refractive power. Since the optical system (100) is a mixture of a spherical lens and an aspherical lens made of glass, various aberrations can be corrected, thereby preventing deterioration of optical performance.

[0309] The receiving optical system (100) may include first lenses (101) to fifth lenses (105) aligned from the object side toward the sensor side along the optical axis (OA). The first to fifth lenses (101, 102, 103, 104, 105) may be defined as a lens unit. For convenience of explanation, the lenses of the receiving optical system may be defined as the first lenses (101) to the fifth lenses (105) sequentially arranged from the object toward the image sensor, and the first to fifth lenses of the receiving optical system may be defined as the fifth to ninth lenses within the sensor system. Conversely, the lenses of the receiving optical system within the receiving system may be defined as the first to fifth lenses from the object toward the image sensor, and the lenses of the transmitting optical system may be defined as the sixth to ninth lenses from the object toward the light source.

[0310]

[0311] The receiving optical system (100) may include an optical filter (155), and the optical filter (155) may be placed between the lenses. Light corresponding to information about an object may pass through the first lens (101) to the third lens (103), the optical filter (155), and the fourth and fifth lenses (104, 105) and be incident on the sensing unit (151). The aperture (ST) may be placed around the sensor-side surface of the third lens (103).

[0312] The first lens (101) may have positive (+) or negative (-) refractive power in the optical axis (OA). The first lens (101) may have negative (-) refractive power. The first lens (101) may include a plastic material or a glass material, and may be, for example, a glass material. The first lens (101) made of a glass material can reduce changes in the center position and radius of curvature due to temperature changes according to the surrounding environment, and can protect the incident side surface of the optical system (100). The first lens (101) is made of a glass material that is not injection molded. The object-side first surface (S1) of the first lens (101) with respect to the optical axis may be convex, and the sensor-side second surface (S2) may be concave. The first surface (S1) and the second surface (S2) may have spherical surfaces. The first lens (101) may have a meniscus shape that is convex toward the object side. Alternatively, the first surface (S1) may have a concave shape and the second surface (S2) may have a convex shape on the optical axis (OA). Alternatively, the first lens (101) may have a concave shape on both sides. Since the first surface (S1) is convex and the second surface (S2) is concave, the incident light can be refracted in a direction close to the optical axis (OA), the gap between the first and second lenses (101, 102) can be reduced, and the effective diameter of the second lens (102) can be reduced. The shape of the lens surface of the first lens (101) can suppress an increase in the effective diameter of the second lens (102). When the refractive index of the first lens (101) is Nd1, the condition of 1.7 < Nd1 or 1.75 < Nd1 < 2.1 can be satisfied. Since the refractive index (Nd1) of the first lens (101) is higher than that of other aspherical lenses, the radius of curvature of the first surface (S1) of the first lens (101) can be increased, and lens manufacturing can be facilitated.If the refractive index (Nd1) of the first lens (101) is lower than the above condition, the lens surface must be formed sharply concave or convex in order to increase the refractive power of the first and second lenses (101, 102). In this case, lens manufacturing is not easy, the lens defect rate increases, and it may cause a decrease in yield.

[0313] The second lens (102) may be positioned between the first lens (101) and the third lens (103). The second lens (102) may have positive (+) or negative (-) refractive power on the optical axis (OA). The second lens (102) may have negative (-) refractive power. The second lens (102) may include a plastic or glass material, and may be provided as a glass material, for example. The second lens (102) may be injection molded.

[0314] The object-side third surface (S3) of the second lens (102) is concave with respect to the optical axis (OA), and the sensor-side fourth surface (S4) may be concave. The third and fourth surfaces (S3, S4) may be aspherical, and as shown in FIG. 14, the conic constant (K) of L2S3, L2S4 and the aspherical coefficients from the 4th to the 14th order (A to F) are shown. The third and fourth surfaces (S3, S4) may be provided without a critical point from the optical axis (OA) to the end of the effective area. Alternatively, the third surface (S3) may be convex, and the fourth surface (S4) may be concave. Alternatively, the second lens (102) may have a convex shape on both sides. When the refractive index of the second lens (102) is Nd2, the condition of 1.75 > Nd2 or 1.55 < Nd2 < 1.75 can be satisfied. Since the refractive index (Nd2) of the second lens (102) is lower than that of other spherical lenses, the difference in the radius of curvature between the third and fourth surfaces (S3, S4) can be provided as small as 10 mm or less. Accordingly, the second lens (102) can refract light incident through the first lens (101) to the entire area of ​​the third lens (103). Since the third surface (S3) of the second lens (102) is concave and has a small radius of curvature, the center spacing between the first and second lenses (101, 102) can be secured. In addition, since the sensor-side fourth surface (S3) of the second lens (102) is concave and has a small radius of curvature, a gap between the second and third lenses (102, 103) can be secured.

[0315]

[0316] The third lens (103) may have positive (+) or negative (-) refractive power in the optical axis (OA). The third lens (103) may have positive (+) refractive power. The third lens (103) may include a plastic or glass material, and may be, for example, a glass material. The third lens (103) is a glass material that is not injection molded. The fifth surface (S5) on the object side of the third lens (103) with respect to the optical axis (OA) may be convex, and the sixth surface (S6) on the sensor side may be convex. The third lens (103) may have a shape in which both sides are convex in the optical axis (OA). At least one or both of the fifth surface (S5) and the sixth surface (S6) may be spherical. 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. Alternatively, the third lens (103) may have a convex meniscus shape toward the object side or the sensor side. Alternatively, the third lens (103) may have a concave shape on both sides of the optical axis.

[0317] When the refractive index of the third lens (103) is Nd3, the condition of Nd2 < Nd3 can be satisfied. When the Abbe number of the third lens (103) is Vd3, the condition of Vd3 < Vd2 can be satisfied. Nd2 is the refractive index of the second lens (102), and Vd2 is the Abbe number of the second lens (102).

[0318]

[0319] The aperture (ST) may be arranged around the sixth surface (S6) on the sensor side of the third lens (103). Since the third lens (103) adjacent to the object side of the aperture (ST) has positive refractive power (F3 > 0), the third lens (103) can refract incident light in the direction of the optical axis and suppress an increase in the effective diameter of the sensor-side or rear-side lenses of the third lens (103). Accordingly, a decrease in the yield by weight of the optical system can be prevented by the third lens (103) and production efficiency can be improved. Here, the focal lengths of the fourth and fifth lenses (104, 105) arranged on the sensor side of the aperture (ST) can have positive values, and the optical system can reduce the TTL within the field of view range.

[0320] Since the sensor-side sixth surface (S6) of the third lens (103) has a convex shape and a small radius of curvature, the center distance between the third lens (103) and the aperture (ST) may be smaller than the center distance between the aperture (ST) and the fourth lens (104). The effective diameter of the optical filter (155) arranged on the sensor side of the third lens (103) may be larger than the effective diameter of the sixth surface (S6) of the third lens (103). The optical filter (155) transmits a laser beam reflected by a subject after being emitted from the transmission optical system of the lidar device, and blocks beams of other wavelengths. The optical filter (155) may be positioned closer to the third lens (103) than to the fourth lens (104) for light blocking and transmission efficiency.

[0321]

[0322] The fourth lens (104) may have positive (+) or negative (-) refractive power in the optical axis (OA). The fourth lens (104) may have positive (+) refractive power. The fourth lens (104) may include a plastic or glass material, and may be provided as a glass material. The fourth lens (104) may not be injection molded. The seventh surface (S7) on the object side of the fourth lens (104) with respect to the optical axis may be convex, and the eighth surface (S8) on the sensor side may be concave. The fourth lens (104) may have a meniscus shape that is convex toward the object. At least one or both of the seventh surface (S7) and the eighth surface (S8) may be spherical. The seventh and eighth surfaces (S7, S8) may be provided without a critical point from the optical axis (OA) to the end of the effective area. Alternatively, the fourth lens (104) may have a convex meniscus shape toward the sensor. Alternatively, the fourth lens (104) may have a concave shape on both sides along the optical axis (OA).

[0323]

[0324] The fifth lens (105) may have positive (+) or negative (-) refractive power in the optical axis (OA). The fifth lens (105) may have positive (+) refractive power. The fifth lens (105) may include a plastic or glass material, and may be provided as a glass material. The fifth lens (105) may be injection molded. The ninth surface (S9) on the object side of the fifth lens (105) with respect to the optical axis may be convex, and the tenth surface (S10) on the sensor side may be concave. The fifth lens (105) may have a meniscus shape that is convex toward the object. Alternatively, the fifth lens (105) may have a double-sided concave shape or a double-sided convex shape in the optical axis (OA). At least one or both of the ninth surface (S9) and the tenth surface (S10) may be aspherical. The aspherical coefficients of the 9th and 10th surfaces (S9, S10) may be provided as L5S9 and L5S10 of FIG. 13. The 9th surface (S9) may be provided without a critical point from the optical axis to the end of the effective area. The 10th surface (S10) may have at least one critical point from the optical axis to the end of the effective area, and the critical point may be arranged closer to the edge than the center of the 10th surface (S10). Here, the critical point may be a point where the sign of the slope value with respect to the optical axis (OA) and the direction perpendicular to the optical axis (OA) changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the slope value is 0. In addition, the critical point may be a point where the slope value of a tangent passing through the lens surface increases and then decreases, or a point where the slope value decreases and then increases.

[0325]

[0326] When the refractive index of the fifth lens (105) is Nd5, the condition of Nd5 < Nd4 can be satisfied. When the Abbe number of the fifth lens (105) is Vd5, the condition of Vd4 < Vd5 can be satisfied. Nd4 is the refractive index of the fourth lens (104), and Vd4 is the Abbe number of the fourth lens (104). The materials of the first, third, and fourth lenses (101, 103, and 104) may be the same. The refractive indices of the first, third, and fourth lenses (101, 103, and 104) may be the same. The materials of the second and fifth lenses (102, and 105) may be the same. The refractive indices of the second and fifth lenses (102, and 105) may be the same. The fifth lens (105) may have a lower refractive index than the refractive indices of the first and third lenses (101, 103) and may have an Abbe number higher than the Abbe number of the first and third lenses (101, 103).

[0327] The effective diameter of the fifth lens (105) may be smaller than that of the fourth lens (104). The effective diameter of the fourth lens (104) may be the largest among the lenses. The lens (103), the fourth lens (104), and the fifth lens (105) may all have positive refractive power. At least one of the object-side surface and the sensor-side surface of the second and fifth lenses (102, 105) may have a free-form surface, that is, a non-rotationally symmetrical surface. The fifth lens (105) may be an aspherical lens closest to the sensing unit (151). By means of the lens surface having the aspherical surface, aberrations such as spherical aberration and chromatic aberration can be improved, and an influence on the resolution can be controlled. By means of the aspherical surface of the lens surface adjacent to the sensing unit (151), optical performance can be improved, and for example, aberration characteristics can be improved and a decrease in resolution can be prevented.

[0328]

[0329] The effective diameter of the first lens (101) may be larger than the effective diameter of the fifth lens (105) closest to the sensing unit (151). Accordingly, the brightness of the optical system (100) can be controlled. By controlling the effective diameters of each of the lenses (101-105), the optical system (100) can control the incident light to compensate for the deterioration of the resolution and optical characteristics due to temperature changes, improve the chromatic aberration control characteristics, and improve the vignetting characteristics of the optical system (100).

[0330] The optical filter (155) can transmit light, for example, a laser wavelength, reflected from a subject after being emitted from a transmission optical system, and block other wavelengths. The transmitted laser wavelength may be in the range of 890 nm to 960 nm or 940 nm ± 10 nm. As another example, the laser wavelength may be in the range of 1550 nm ± 10 nm. The optical filter (155) may be a bandpass filter. The optical filter (155) may be arranged between two different lenses among the lenses. The optical filter (155) may be arranged between the spherical lenses. The optical filter (155) may be arranged between the third lens (103) and the fourth lens (104).

[0331]

[0332] The optical filter (155) can perform an operation of passing only light of a specific wavelength or only light whose wavelength belongs to a specific band, and blocking the remaining light. The optical filter (155) can actively perform the filtering operation. To this end, the optical filter (155) can include an active device that, in response to an external control signal, passes only light whose center wavelength is a specific wavelength and blocks light of other wavelengths. The control signal provided to the optical filter (155) can include information about the center wavelength of the light to pass through the active device, wherein the center wavelength can correspond to the center wavelength of the light emitted from the transmission optical system. Consequently, the control signal provided to the optical filter (155) is a control signal that matches the center wavelength of the light emitted from the transmission optical system with the center wavelength of the light to pass through the active device of the optical filter (155). Due to the active device included in the optical filter (155), the optical filter (155) can selectively pass only the desired light and block other noise light including natural light. Therefore, the signal-to-noise ratio (S / N) of the lidar system can be increased. As an example of the active device, the optical filter can include a tunable band-pass filter. The operating method of the tunable band-pass filter can be a liquid crystal method or an acousto-optic method.

[0333]

[0334] The third lens (103) is disposed on the object side of the optical filter (155), has a refractive index greater than that of the second lens (102), and may have a central thickness greater than that of the first lens (101). The fourth lens (104) is disposed on the sensor side of the optical filter (155), has a refractive index greater than that of the fifth lens (105), and may have a central thickness greater than that of the first lens (101). The central distance between the third lens (103) and the fourth lens (104) may be greater than the thickness of the optical filter (155). The central distance between the third lens (103) and the fourth lens (104) may be the largest among the central distances between two adjacent lenses within the optical system (100).

[0335]

[0336] When the radius of curvature is described as an absolute value, the lens surface having the minimum radius of curvature with respect to the optical axis (OA) within the optical system (100) may be the sensor-side second surface (S2) of the first lens (101) among the spherical surfaces or the object-side ninth surface (S9) of the fifth lens (105). Accordingly, the center spacing between the first lens (101) and the second lens (102) may be spaced apart, and the center spacing between the fourth lens (104) and the fifth lens (105) may be reduced. The lens surface having the maximum radius of curvature within the optical system (100) may be the object-side surface of the first lens (101) among the spherical surfaces. The lens surface having the second largest radius of curvature within the optical system (100) may be the object-side surface of the third lens (103) among the spherical surfaces. By adjusting the radius of curvature of the above lenses, it is possible to reduce lens ghosting by preventing random reflection between adjacent lens surfaces and also to prevent (MPI: Multi-path interference) caused by lens ghosting. Since the object-side first surface (S1) of the first lens (101) is provided with a radius of curvature of 200 mm or more, for example, more than 20 times the radius of curvature of the second surface (S2), it is possible to reduce distortion of reflected light and further increase the depth of field, thereby improving image quality under low-light conditions.

[0337]

[0338] The optical system (100) or sensor system may include a sensing unit (151). The sensing unit (151) may detect light that has sequentially passed through the lenses. The sensing unit (151) may detect light and convert it into an electrical signal. The sensing unit (151) may obtain various information about the subject. The sensing unit (151) may detect time delay or phase difference information from the incident light, and based on this, may obtain distance information to the subject, position information of the subject, depth image of the subject, etc. To this end, the sensing unit (151) may include a device that may detect incident light, such as an image sensor, for example, a Charge Coupled Device (CCD) or a Complementary Metal Oxide Semiconductor (CMOS). As another example, the sensing unit may include a Time to Digital Converter (TDC). Here, the effective length of the sensing unit (151) is the maximum length in the diagonal direction orthogonal to the optical axis (OA), and here, the number of lenses having an effective diameter larger than the effective length of the sensing unit (151) is 4 to 6, and there may be no number of lenses having an effective diameter smaller than the effective length of the sensing unit (151).

[0339]

[0340] At least two lenses may be arranged between the optical filter (155) and the sensing unit (151). For example, the fourth and fifth lenses (104, 105) may be arranged between the optical filter (155) and the sensing unit (151). A spherical lens and an aspherical lens may be arranged between the optical filter (155) and the sensing unit (151). The optical filter (155) may be arranged between the spherical third lens (103) and the spherical fourth lens (104). The optical filter (155) may be arranged between the sensor-side sixth surface (S6) of the third lens (103) and the object-side seventh surface (S7) of the fourth lens (104). The optical filter (155) 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 (155) can, as another example, transmit a range of 1550 nm ± 10 nm and block other wavelengths. The optical filter (155) can transmit a wavelength corresponding to a laser beam transmitted from a transmission optical system of a lidar device and block light corresponding to the remaining ambient light.

[0341] The cover glass (153) is placed between the last lens and the sensing unit (151), and protects the upper portion of the sensing unit (151) and can prevent the reliability of the sensing unit (151) from being deteriorated. The cover glass (153) can be removed. The cover glass (153) may be a protective glass.

[0342]

[0343] The optical system (100) may include an aperture (ST). The aperture (ST) may control the amount of light incident on the optical system (100). The aperture (ST) may be arranged on the periphery between the third lens (103) and the fourth lens (104). The aperture (ST) may be arranged on the periphery between the spherical third lens (103) and the spherical fourth lens (104). The aperture (ST) may be arranged on the periphery between the sensor-side sixth surface (S6) of the third lens (103) and the object-side seventh surface (S7) of the fourth lens (104). The aperture (ST) may be arranged on the periphery between the third lens (103) and the optical filter (155). The lens surface on which the aperture (ST) is arranged is intended to more efficiently control and guide the amount of light of the optical system (100). As in the embodiment, the aperture (ST) may be arranged on the sensor-side surface of the third lens (103). Alternatively, the aperture (ST) may be arranged on the periphery of the object-side surface or the sensor-side surface of the second lens (102). Alternatively, at least one lens selected from the plurality of lenses, for example, the object-side surface or the sensor-side surface of the third lens (103), may function as an aperture.

[0344]

[0345] In the optical system (100) of the embodiment, the sum of the refractive indices of the lenses may be greater than 5, for example, 8.0 or more, and preferably, in the range of 8.0 to 12.0, and the average of the refractive indices may be in the range of 1.70 to 1.80. The sum of the Abbe numbers of each of the lenses may be 180 or less, for example, in the range of 120 to 180, and the average of the Abbe numbers may be 47 or less, for example, in the range of 23 to 47. By controlling the refractive indices of the lenses in the optical system (100), it is possible to prevent degradation of optical performance for temperature changes from -45 to 120 degrees and to optimize thermal compensation. In addition, by controlling the Abbe number, it is possible to minimize the deviation of the spot size of incident light, i.e., to minimize the spot diagram size.

[0346] In the receiving optical system, the sum of the central thicknesses of all lenses may be 15 mm or more, for example, in the range of 15 mm to 25 mm, and the average of the central thicknesses may be 4.9 mm or less, for example, in the range of 2.9 mm to 4.9 mm. The sum of the central spacings between the lenses on the optical axis (OA) may be 15 mm or more, for example, in the range of 15 mm to 30 mm, and may be less 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 (100) may be provided as 20 mm or less, for example, in the range of 9 mm to 20 mm. By controlling the thickness of each lens within the optical system (100), it is possible to prevent degradation of optical performance for temperature changes from -45 to 120 degrees and to optimize thermal compensation.

[0347]

[0348] In the receiving optical system according to an embodiment of the invention, the angle of view may be 100 degrees or more, for example, in the range of 118 degrees or more to 138 degrees, preferably, in the range of 128 degrees ± 10 degrees. The F number of the optical system or the camera module may be 1.2 or less, for example, in the range of 0.7 to 1.2 or in the range of 0.7 to 0.9. The diagonal length of the sensing unit (151) may be 6.04 mm ± 0.5 mm, and may be greater than the sensor height in the vertical direction. The invention can provide a vehicle lidar device that can suppress a change in a focus imaging position due to a change in temperature by stacking glass lenses, and correct various aberrations by providing an aspherical lens.

[0349]

[0350] Since the embodiment is a receiving optical system applied to a lidar device, the first lens (101) may be provided with a glass material. This is because glass has the advantage of being scratch-resistant and insensitive to external temperature compared to plastic materials. In order to more effectively prevent scratches caused by foreign substances or when placed inside a vehicle, a glass lens may be used as the first lens (101), and the object-side surface of the first lens (101) may have a convex shape to prevent external foreign substances from accumulating. The lidar device can detect the distance, direction, speed, temperature, material distribution, and concentration characteristics to an object when the vehicle is running. Such a lidar device may be used for an advanced driver assistance system (ADAS). The receiving optical system (100) according to the embodiment may further include a reflective member (not shown) for changing the path of light. The reflective member may be implemented as a prism that reflects incident light toward the lenses. Hereinafter, the optical system according to the embodiment will be described in detail.

[0351]

[0352] When the lenses having negative refractive power are the first lens group and the lenses having positive refractive power are the second lens group, the aperture (ST) and the optical filter (155) may be arranged within the second lens group. The aperture (ST) and the optical filter (155) may be arranged between the spherical lens surfaces of the second lens group.

[0353] As shown in FIGS. 11 and 12, the center thickness of the first to fifth lenses (101 to 105) is represented by CT1 to CT5, the edge thickness at the end of the effective area of ​​each lens is represented by ET1 to ET5, and the center gap between two adjacent lenses is represented by CG1 to CG4. The first to fifth lenses (101 to 105) can satisfy the following conditions.

[0354] Condition 1: CT1 < CT3 Condition 2: CT2 < CT5 < CT4

[0355] Condition 3: (CT4-CT5) < (CT3-CT2) Condition 4: ET3 < ET2 < ET1

[0356] Condition 5: ET4 < ET3 < CT5

[0357]

[0358] One of the center thicknesses (CT3, CT4) of the third and fourth lenses (103, 104) is the largest among the lenses, and one of the center thicknesses (CT1, CT2) of the first and second lenses (101, 102) is the smallest among the lenses. The maximum center thickness may be three times or less than the minimum center thickness, and the difference between the maximum center thickness and the minimum center thickness may be 4 mm or less. That is, even if the lenses made of spherical materials provide a thin center thickness, the optical performance may not be degraded, and the thickness of the sensor system may be provided in a slim manner. By adjusting the thickness of these lenses, thermal compensation can be performed for temperatures that change from low to high temperatures.

[0359] When describing the center spacing (CG) between adjacent lenses, the center spacing (CG3) between the third lens (103) and the fourth lens (104) is maximum and is greater than the center spacing (CG1) between the first and second lenses (101, 102). The center spacing (CG4) between the fourth and fifth lenses (104, 105) 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 3 mm to 6 mm. In addition, by providing the maximum center spacing between the lenses to be greater than the maximum center thickness of each lens, a receiving optical system in which the center spacing between the spherical lens and the aspherical lens does not increase can be provided. In addition, since the maximum center spacing between the lenses is provided to be 1.5 times greater than the minimum center thickness of each lens, the optical path can be controlled.

[0360]

[0361] In terms of the effective diameter, the lens having the maximum effective diameter may be the fourth lens (104) arranged on the sensor side of the optical filter (155). The fourth lens (104) having the maximum effective diameter may be a spherical lens made of glass. The lens surface having the maximum effective diameter may be the first surface (S1) of the first lens (101). The lens having the minimum effective diameter may be the second lens (102) adjacent to the first lens (101). The lens surface having the minimum effective diameter may be either the third surface (S3) of the second lens (102) or the tenth surface (S10) of the fifth lens (105), and may be less than 70% of the first surface (S1). The effective diameter of each of the first to fifth lenses (101-105) may be greater than the diagonal length of the effective area of ​​the sensing unit (151). The fifth lens (105) has an aspherical surface and can guide light incident through the fourth lens (104), which is a spherical lens, to the sensing unit (151).

[0362] Fig. 12 is an example of lens data of the optical system of the embodiment of Fig. 11. As shown in Fig. 12, the radius of curvature (Radius) of the optical axis (OA) of the first to fifth lenses (101, 102, 103, 104, 105), the center thickness (CT) of the lenses, the center distance (CG) between the lenses, the refractive index (Refractive index) at the d-line, the Abbe's Number, and the size of the effective radius can be set. As shown in Fig. 13, the lens surfaces of the second and fifth lenses (102, 105) of the embodiment may include an aspherical surface having a 14th-order aspherical surface coefficient. For example, the object-side surface and the sensor-side surface of the second and fifth lenses (102, 105) may be lens surfaces having a 14th-order aspherical surface coefficient. As described above, an aspherical surface with a 14th aspherical coefficient (a non-zero value) can significantly change the aspherical shape of the periphery, and thus can provide good optical performance correction in the periphery of the field of view (FOV).

[0363] The focal lengths (F1, F2) of the first and second lenses (101, 102) may have negative refractive power, and the focal lengths (F3, F4, F5) of the third, fourth, and fifth lenses (103, 104, 105) may have positive refractive power. Here, among the lenses, the second lens (102) has negative refractive power, and the third lens (103) has positive refractive power. Therefore, according to conditions 1 and 2, the refractive index of the third lens (103) is greater than the refractive index of the second lens (102), and the dispersion value of the third lens (103) is less than the dispersion value of the second lens (102). Chromatic aberration occurring in a spherical lens can be corrected by the spherical lens. In addition, by satisfying that the refractive index difference between the second lens (102) and the third lens (103), which are spherical lenses arranged in succession, is 0.1 or more and 0.15 or less, and the Abbe number difference is 10 or more and 20 or less, the chromatic aberration occurring in the spherical lens can be compensated for by the spherical lens.

[0364] Optical systems experience chromatic aberration, which is corrected using spaced aspherical lenses. As temperatures change from low to high, the lenses contract and expand repeatedly. Since lenses made of the same material exhibit the same degree of change in lens characteristics with temperature, it is effective to compensate for chromatic aberration between lenses made of the same material, even when the temperature changes. For example, as shown in Table 4, when the temperature of the lens barrel or receiving optical system changes from -45°C (low temperature), 22°C (room temperature), and 90°C (high temperature), there is little change in optical characteristics.

[0365] Table 4 compares changes in optical characteristics such as EFL, BFL, F number (F#), TTL, and field of view (FOV) at room temperature, low temperature, and high temperature in an optical system according to an embodiment, and it can be seen that the change rate of optical characteristics at low temperature is 5% or less, for example, 3% or less or 2% or less, based on room temperature, and the change rate of optical characteristics at high temperature is 5% or less, for example, 3% or less or 2% or less, based on room temperature.

[0366] Low temperature Room temperature High temperature Low temperature / Room temperature (%) High temperature / Room temperature (%) EFL 3.348 3.349 3.350 99.98% 100.04% BFL 4.59 24.588 4.606 100.09% 100.38% F# 0.80 20.80 20.80 29 9.95% 100.06% TTL 42.95 443.000 43.04 7 99.89% 100.11% FOV 128.89 0 128.80 9 128.70 4 100.06% 99.92%

[0367] Therefore, as shown in Table 4, it can be seen that the change in optical characteristics according to the temperature change from low temperature to high temperature, for example, the change rate of effective focal length (EFL), TTL, BFL, F number, and field of view (FOV), is 10% or less, that is, 5% or less, for example, in the range of 0 to 5%. This means that even if at least one or two or more aspherical lenses are used, the design enables temperature compensation for the aspherical lenses, thereby preventing a decrease in the reliability of the optical characteristics. The receiving optical system of the embodiment disclosed above can effectively control aberration characteristics such as chromatic aberration and distortion aberration, and can have good optical performance at the center and periphery of the field of view (FOV). Here, EFL is the effective focal length of the optical system, BFL is the optical axis distance from the last lens, i.e., the fifth lens (105), to the detection unit (151), i.e., the surface of the image sensor, Fno is the F number of the optical system, TTL is the optical axis distance from the surface of the detection unit (151) of the first lens (101), i.e., the surface of the image sensor, and FOV is the angle of view of the receiving optical system.

[0368]

[0369] When comparing the focal lengths in absolute values, the focal length of the fourth lens (104) is the largest among the lenses, and can be 10 mm or more and 35 mm or less. Accordingly, the optical system can have improved MTF characteristics, aberration control characteristics, resolution characteristics, etc. in the set angle of view range, and can have good optical performance in the periphery of the angle of view.

[0370] In addition, the receiving optical system (100) according to the embodiment may have good optical performance according to temperature changes in a temperature range from low temperature (-45 degrees) to high temperature (120 degrees) and may have set distortion characteristics. For example, the optical system (100) may be based on any one of the following mapping functions of a wide-angle lens. Specifically, when the distance (mm) from the surface center (0F) of the image sensor, which is the detection unit (151), to 1 field, and in detail, half of the maximum diagonal length (mm) of the effective area of ​​the image sensor is defined as ImgH, the angle of view (FOV) is defined as θ, and the total focal length (mm) of the optical system (100) is defined as F, the mapping function of the wide-angle or fisheye optical system may be defined as follows.

[0371] Equidistance mapping can be defined as ImgH = F*θ, and Equal Area (Equisolid angle) mapping can be defined as ImgH = 2*F*sin(θ / 2). In addition, Orthographic mapping can be defined as ImgH = f*sinθ, and Stereographic mapping can be defined as ImgH = 2*F* tan(θ / 2). Here, * represents multiplication. Looking at the transmission optical system of Fig. 12, it has a micro lens array of a diffuser of the transmission optical system, and the optical path of light passing through the micro lens array causes a change in the Field of Illumination (FOI) in the on-axis direction separate from the direction of light propagation. In a comparative example, it can be seen that the FOI changes in the off-axis after passing through the one-dimensional micro lens array. Here, looking at the light path after passing through the diffuser, the comparative example has a light path of F*θ, and the embodiment has a light path of f*sinθ.

[0372]

[0373] Referring to FIG. 14, the receiving optical system (100) may have a distortion characteristic set compared to a design standard (comparative example) as it goes from a 0 degree field of view to a maximum half-angle of view (HFOV, 1 / 2 of the FOV). For example, it can be seen that the embodiment of the optical system (100) further increases as the sensor height increases as it goes from a 0 degree field of view to a maximum half-angle of view (HFOV, 1 / 2 of the FOV), and may have a distortion characteristic that satisfies compared to other examples of mapping such as Stereographic, equidistance, rectilinear, and Equisolid. In detail, the embodiment may satisfy the distortion characteristic compared to the other example 1 above.

[0374] In addition, the receiving optical system (100) can have a distortion characteristic set compared to other examples as it goes from a 0 degree field of view to a maximum half-field of view (HFOV, 1 / 2 of the FOV), thereby providing an optical system that satisfies the orthographic projection type. Here, the ratio for the distortion characteristic can mean the value of ImgH at a specific half-field of view position, calculated as ((Other example - embodiment) / embodiment * 100). Accordingly, the optical system according to the embodiment can prevent the optical characteristics from changing according to temperature change in a temperature range from a low temperature (-45 degrees) to a high temperature (120 degrees) based on the Equal Area mapping method, and can have improved optical performance in various temperature ranges.

[0375]

[0376] Fig. 15 is a graph showing the diffraction MTF (Modulation Transfer Function) at low, room, and high temperatures in the optical system of Fig. 11, and is a graph showing the modulation ratio according to the spatial frequency. As shown in Fig. 15, in an embodiment of the invention, the deviation of the MTF at low or high temperature with respect to room temperature may be less than 10%, that is, 7% or less. Here, each MTF curve was measured from 0.000 mm to 3.170 mm in units of 0.302 mm.

[0377] Figures 16 to 8 are graphs showing aberration characteristics at low temperatures, room temperatures, and high temperatures in the optical system of Figure 11. Figures 16 to 18 are graphs measuring spherical aberration (longitudinal spherical aberration), astigmatic field curves, and distortion from left to right in the aberration graphs. In Figures 16 to 18, the X-axis may represent a focal length (mm) and a 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 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 wavelength bands of about 940 nm. In the aberration diagrams of FIGS. 16 to 18, the closer the curves at low temperature, room temperature, and high temperature are to the Y-axis, the better the aberration correction function can be interpreted. That is, the optical system (100) according to the embodiment has improved resolution and can have good optical performance in the center and periphery of the field of view (FOV). Here, the low temperature is -20 degrees or lower, for example, in the range of -20 to -50 degrees, the room temperature is in the range of 22 degrees ± 5 degrees or in the range of 18 degrees to 27 degrees, and the high temperature can be 85 degrees or higher, for example, in the range of 85 degrees to 120 degrees. Accordingly, it can be seen that the decrease in the luminance ratio (modulation) from the low temperature to the high temperature of FIGS. 16 to 18 is less than 10%, for example, 5% or lower, or is almost unchanged.

[0378]

[0379] According to an embodiment of the invention, a receiving optical system can prevent a deterioration in optical performance from low to high temperatures by considering the characteristics of a vehicle optical system. For example, after designing a lens at room temperature, the value of the dn / dt, which is a temperature-dependent refractive index change coefficient, is assembled by considering the power combination of each lens, and the value of the temperature coefficient (dn / dt) according to the refractive index of the lens and the defocus for the thickness variable according to low, room, and high temperatures can be set to 5㎛ or less. For this purpose, the first, third, and fourth lenses (101, 103, and 104) are made of a spherical glass material, and the second and fifth lenses (102, 105) are made of an aspherical glass material.

[0380] In an embodiment of the invention, the optical filter (155) can be positioned close to the aperture (ST), that is, between the aperture (ST) and the fourth lens (104). The filter of the comparative example is positioned between the sensing unit and the last lens. Therefore, the invention can minimize the incident angle of light incident on the optical filter (155). That is, the incident angle of the main beam incident on the optical filter (155) can be less than 20 degrees at most, that is, 18 degrees or less. It is possible to overcome the material limitation that the filter transmittance range shifts depending on the incident angle on the optical filter (155). For example, when an existing filter is positioned between the sensing unit and the last lens, the incident angle of the main beam incident on the filter is about 45 degrees, but the optical filter (155) of the invention is positioned around the aperture (ST), so that the incident angle of the main beam is reduced to less than 20 degrees, for example, 18 degrees or less. Considering the transmittance curve when the main beam has an incident angle of 0 degrees and the transmittance curves when the main beam has an incident angle of 20 degrees and 40 degrees in the optical filter (155) described above, there is an effect that the filter area can be utilized more widely from the incident angle of the main beam of 0 degrees to an angle less than 20 degrees at most. Fig. 19 is a graph showing the transmittance (%) curves when the incident angle of the main beam incident on the filter of the invention is 0 degrees, 20 degrees, and 40 degrees.

[0381] The incident angle of the chief beam at the incident surface of the optical filter (155) is inspected using AOI (Automated Optical Inspection) equipment, and it can be seen that the incident angle of the chief beam incident on the filter from 0 field to 1.05 field and the incident angle in different directions (±Y direction, ±X direction) ranges from 0 degrees to a maximum of 17.55 degrees. Accordingly, the problem of the incident angle of the chief beam shifting at low and high temperatures compared to room temperature can be minimized.

[0382]

[0383] The receiving optical system (100) according to the embodiment disclosed above can satisfy at least one or two or more of the mathematical equations described below. Accordingly, the optical system (100) according to the embodiment can have improved optical characteristics. For example, when the optical system (100) satisfies at least one mathematical equation, the optical system (100) can effectively control aberration characteristics such as chromatic aberration and distortion aberration, and can have good optical performance in the center and periphery of the field of view (FOV). In addition, the receiving optical system (100) can have improved resolution. In addition, the thickness of the lens at the optical axis (OA) described in the mathematical equations and the spacing between adjacent lenses at the optical axis (OA) can refer to the embodiment disclosed above. The center thickness of the lenses of the receiving optical system can be defined as CT1 to CT5, and the edge thickness can be defined as ET1 to ET5.

[0384] [Mathematical Formula 1] 0 < CT1 / CT2 < 3

[0385] CT1 is the central thickness of the first lens (101), and CT2 is the central thickness of the second lens (102). By setting the central thickness (CT1) of the first lens (101) and the central thickness (CT2) of the second lens (102) in mathematical expression 1, it is possible to prevent a decrease in the rigidity of the first lens (101) and control factors affecting aberration. Preferably, mathematical expression 1 can satisfy 0.5 < CT1 / CT2 < 1.2.

[0386] [Mathematical Formula 2] 2 < CA11 / CT1 < 10

[0387] CA11 is the effective diameter of the object-side surface (S1) of the first lens (101). In mathematical expression 2, the center thickness (CT1) of the first lens (101) and the effective diameter (CA11) of the object-side surface (S1) of the first lens (101) can be set, and when these are satisfied, the strength and optical properties of the glass lens can be prevented from being deteriorated. If it is lower than the range of mathematical expression 1, the lens may be damaged or the incidence efficiency may be reduced, and if it is larger than the above range, the TTL may increase and the weight of the optical system may become heavier. Preferably, mathematical expression 2 can satisfy 5 < CA11 / CT1 < 8.

[0388] [Mathematical Formula 3] 0 < CT5 / CT4 < 3

[0389] CT4 is the central thickness of the fourth lens (104), and CT5 is the central thickness of the fifth lens (105). In mathematical expression 3, the central thickness (CT5) of the fifth lens (105) and the central thickness (CT4) of the fourth lens (104) can be set, thereby optimizing thermal compensation according to temperature changes from low to high temperatures, and preventing deterioration of optical performance. Preferably, mathematical expression 3 can satisfy 0.5 < CT5 / CT4 < 1.

[0390] [Mathematical Formula 3-1] 0 < CT5 / CT3 < 3

[0391] CT3 is the center thickness of the third lens (103). By setting the center thicknesses (CT3, CT5) of the third and fifth lenses (103, 105) in Mathematical Expression 3-1, light refracted from the object-side lenses can be guided to the sensing unit (151). Preferably, Mathematical Expression 3-1 can satisfy 0.5 < CT5 / CT3 < 1. Accordingly, the fifth lens (105) closest to the sensing unit (151) can thicken the center thickness (CT5) and refract light refracted through the object-side lenses to the entire area of ​​the sensing unit (151) without significantly increasing the effective diameter.

[0392] [Mathematical Formula 4] 0 < CT5 / (CT1+CT2) < 3

[0393] In mathematical expression 4, the central thickness (CT5) of the fifth lens (105) is set to be greater than the sum of the central thicknesses (CT1, CT2) of the first and second lenses (101, 102), so that light refracted from the object-side lens can be guided to the sensing unit (151). Preferably, mathematical expression 4 can satisfy 0.5 < CT5 / (CT1+CT2) < 1. Accordingly, the central thickness (CT5) of the fifth lens (105) closest to the sensing unit (151) can be thickened, and the effective diameter may not increase significantly.

[0394] [Equation 5] 1 < CG3 / CT5 < 3

[0395] CG3 is the center spacing between the third and fourth lenses (103, 104). In mathematical expression 5, the center spacing (CG3) between the third and fourth lenses (103, 104) can be set to be larger than the center thickness (CT5) of the fifth lens (105). Accordingly, the third lens (103) can secure a space for installing the optical filter (155) between the convex sensor-side surface and the convex object-side surface of the fourth lens (104). The effective diameter of the third lens (103) can be set to be larger than the effective diameter of the second lens (102). Preferably, 1.2 < CC3 / CT5 < 2.2 can be satisfied.

[0396] [Equation 6] 0 < CG4 / CG1 < 1

[0397] CG1 is the center spacing between the first and second lenses (101, 102), and CG4 is the center spacing between the fourth and fifth lenses (104, 105). In mathematical expression 6, by setting the center spacing (CG1) between the first and second lenses (101, 102) and the center spacing (CG4) of the fourth and fifth lenses (104, 105), the center spacings between the spherical lenses (101, 104) and the aspherical lenses (102, 105) can be set. Preferably, 0.1 < CG4 / CG1 < 0.5 can be satisfied.

[0398] [Equation 6-1] 0 < CG4 / CG2 < 1

[0399] In mathematical expression 6-1, the center spacing (CG2) between the second and third lenses (102, 103) is set to be larger than the center spacing (CG4) between the fourth and fifth lenses (104, 105), so that the center spacing between the two object-side lenses (102, 103) of the aperture (ST) is set to be larger than the center spacing between the two sensor-side lenses (104, 105) of the aperture (ST), thereby controlling the light paths on the incident and exit sides of the aperture (ST). Preferably, 0.3 < CG4 / CG2 < 0.8 can be satisfied.

[0400] [Mathematical Formula 7] 2 < CG3 / OFt < 5

[0401] CG3 is the center spacing between the third and fourth lenses (103, 104), and OFt is the thickness of the optical filter (155). In mathematical expression 7, by making the center spacing (CG3) between the third and fourth lenses (103, 104) larger than the thickness of the optical filter (155), a space in which the optical filter (155) can be installed can be secured in the area between the third and fourth lenses (103, 104). Preferably, 2.8 < CG3 / OFt < 5 can be satisfied.

[0402] [Equation 8] 0.3 < CG3 / (CT1+CG1+CT2) < 1.5

[0403] In mathematical expression 8, the center distance (CG3) between the third and fourth lenses (103, 104) can be set to be greater than the optical axis distance between the object-side surface of the first lens (101) and the sensor-side surface of the second lens (102). Accordingly, the effective diameter of the object-side surface of the first lens (101) can be set to the maximum, and the second lens (102) can have a concave shape on both sides and be set to the minimum effective diameter. Preferably, 0.3 < CG2 / (CT1+CG1+CT2) < 1 can be satisfied.

[0404] [Equation 10] 1.70 < Nd1

[0405] Nd1 is the refractive index at the d-line of the first lens (101). In mathematical expression 10, by setting the refractive index of the first lens (101) high, the factor affecting the reduction of the third-order aberration (Seidel aberration) of the optical system can be adjusted, and the aberration that may occur as the TTL becomes somewhat longer can be reduced. Mathematical expression 10 can preferably satisfy 1.75 < Nd1 < 2.1. If it is designed to be lower than the lower limit of mathematical expression 10, the performance of reducing the aberration can be obtained, and the refractive power of the first lens may be weakened so that light cannot be collected efficiently, which may lower the performance of the optical system. If it is designed to be higher than the upper limit of mathematical expression 10, there is a disadvantage in that it is difficult to obtain materials. Additionally, when the refractive index of the first lens (101) is designed to be lower than the lower limit of mathematical expression 10, the radius of curvature of the first and second lenses can be increased to increase the refractive power of the first and second lenses.

[0406] [Mathematical Formula 10-1] 1.7 ≤ Aver(Nd1:Nd5) ≤ 1.8

[0407] Aver(Nd1:Nd5) is the average of the refractive index values ​​at the d-line of the first to fifth lenses. When mathematical expression 10-1 is satisfied, the optical system (100) can set the resolution and suppress the influence on TTL.

[0408] [Equation 10-2] GMn_Aver < GLn_Aver

[0409] GLn_Aver is the average of the refractive index values ​​at the d-line of the spherical glass lenses, and GMn_Aver is the average of the refractive index values ​​at the d-line of the aspherical glass lenses, which are glass molds. The spherical lens is a lens made of a non-injection-molded glass material, and the aspherical lens is a lens made of an injection-molded glass material. Spherical lenses with a high refractive index can be positioned on the object side of the aspherical lens to increase chromatic dispersion.

[0410]

[0411] [Equation 11] 0 < Nd1 / Nd3 < 1.5

[0412] Nd1 and Nd3 are the refractive indices of the first and third lenses (101 and 103) at the d-line. In Equation 11, the difference in the refractive indices of the first lens (101) and the third lens (103) can be reduced, thereby preventing the reduction in color dispersion caused by lenses made of glass. Preferably, in Equation 11, Nd1 and Nd3 can be the same.

[0413] [Equation 12] 0 < Nd3 / Nd4 < 1.5

[0414] Nd3 and Nd4 are the refractive indices of the third and fourth lenses (103 and 104) at the d-line. In Equation 12, by setting the refractive index of the third lens (103) higher than that of the fourth lens (104), the chromatic dispersion caused by spherical material lenses and the chromatic dispersion caused by aspherical lenses can be controlled. Preferably, in Equation 12, Nd3 and Nd4 can be the same.

[0415] [Equation 13] (Vd4*Nd4) < (Vd2*Nd2)

[0416] Nd2, Nd4 are the refractive indices at the d-line of the second and fourth lenses (102, 104), and Vd2, Vd4 are the Abbe numbers of the second and fourth lenses. In mathematical expression 13, by setting the product of the refractive index and Abbe number of the second lens (102) to be greater than the product of the refractive index and Abbe number of the fourth lens (104), the color dispersion by the spherical material lens and the color dispersion by the aspherical lens can be controlled.

[0417] [Mathematical Formula 13-1] (Vd3*Nd3) < (Vd5*Nd5)

[0418] Nd3 and Nd5 are the refractive indices of the 3rd and 5th lenses (103 and 105) at the d-line, and Vd3 and Vd5 are the Abbe numbers of the 3rd and 5th lenses. In mathematical expression 13-1, by setting the product of the refractive index and Abbe number of the 5th lens (105) to be greater than the product of the refractive index and Abbe number of the 3rd lens (103), the color dispersion by the spherical material lens and the color dispersion by the aspherical lens can be controlled.

[0419]

[0420] [Equation 14] BFL < D1

[0421] BFL is the optical axis distance from the surface of the sensing unit (151) to the center of the sensor-side surface of the last lens, i.e., the fifth lens (105), and D1 is the optical axis distance from the surface of the sensing unit (151) to the surface of the optical filter (155). By satisfying mathematical expression 14, the optical filter (155) can be positioned adjacent to the aperture (ST) or positioned around a lens closer to the object side than the last lens.

[0422] [Equation 14-1] 1 < SD / D1 < 1.2

[0423] SD is the distance in the direction of the optical axis from the aperture (ST) to the surface of the sensing unit (151). When mathematical expression 14-1 is satisfied, the optical filter (155) may be adjacent to the aperture (ST) and placed on the sensor side of the aperture (ST).

[0424] [Equation 14-2] BFL < CG3 < D1

[0425] [Equation 15] CT5 < TTL / 3 < D1

[0426] CT5 is the center thickness of the fifth lens (105), and TTL is the optical axis distance from the first lens (101) to the surface of the sensing unit (151). In mathematical expression 15, the optical axis distance (D1) between the optical filter (155) and the sensing unit (151) can be set to be greater than the center thickness of the fifth lens (105) adjacent to the sensing unit (151) and also greater than half the value of TTL. Accordingly, the incident angle of the main beam incident on the optical filter (155) can be reduced to less than 20 degrees, and the problem of the incident angle shifting at low and high temperatures compared to room temperature can be minimized. Preferably, D1 satisfies 18 mm < D1 < 25 mm.

[0427] [Equation 16] 0.5 < D1 / D2 < 1.5

[0428] D1 is the optical axis distance from the surface of the sensing unit (151) to the optical filter (155), and D2 is the optical axis distance from the center of the object-side surface of the first lens (101) to the object-side surface of the optical filter (155). When mathematical expression 16 is satisfied, the optical filter (155) may be placed between the lenses, or may be placed between the third and fourth lenses, or at a position adjacent to the aperture (ST). Accordingly, the incident angle of the main beam incident on the optical filter (155) can be reduced to less than 20 degrees, and the problem of the incident angle shifting at low and high temperatures compared to room temperature can be minimized. Preferably, D2 < D1 can be satisfied.

[0429] [Equation 17] 0 < OFt < CG3

[0430] When the thickness (Oft) of the optical filter and the center spacing between the third and fourth lenses (103, 104) satisfy mathematical expression 17, the optical filter (155) can be placed between the third and fourth lenses. In addition, 0 < OFt < CG3 < EG3 can be satisfied, where EG3 is an edge spacing between the third and fourth lenses. In addition, 0 < OFt < CG_Min can be satisfied, where CG_Min represents the minimum spacing among the center spacings between two adjacent lenses.

[0431]

[0432] [Mathematical Formula 18] 1 < CA11 / CA21 < 5

[0433] CA11 refers to the effective diameter of the first surface (S1) of the first lens (101), and CA21 refers to the effective diameter of the third surface (S3) of the second lens (102). When mathematical expression 18 is satisfied, the optical system (100) can control the incident light and set the factors affecting aberration, and preferably, 1 < CA11 / CA21 < 2.5 can be satisfied.

[0434] [Equation 19] 0 < CA22 / CA31 < 2

[0435] CA22 refers to the effective diameter of the fourth surface (S4) of the second lens (102), and CA31 refers to the effective diameter of the fifth surface (S5) of the third lens (103). When mathematical expression 19 is satisfied, the optical system (100) can control the incident light path and set the sensor-side surface of the second lens (102) to a concave shape. Preferably, mathematical expression 19 can satisfy 0.5 < CA22 / CA31 < 1.

[0436] [Equation 20] 0.5 < CA42 / CA51 < 2

[0437] CA42 refers to the effective diameter of the eighth surface (S8) of the fourth lens (104), and CA51 refers to the effective diameter of the ninth surface (S9) of the fifth lens (105). When mathematical expression 20 is satisfied, the optical system (100) can set a light path that is incident on the sensing unit (151) through the fourth lens (104) and the fifth lens (105). Mathematical expression 20 can preferably satisfy 1 < CA42 / CA51 < 1.5.

[0438] [Mathematical Formula 21] 1 < CA11 / CA52 < 5

[0439] CA11 is the effective diameter of the first surface (S1) of the first lens (101), and CA52 means the effective diameter of the tenth surface (S10) of the fifth lens (105). When the optical system (100) satisfies mathematical expression 21, the incident amount of the first lens, the spherical lens, can be increased, and the path of light toward the sensing unit can be set through the last lens, the aspherical lens. Mathematical expression 21 can preferably satisfy 1 < CA11 / CA52 < 2.5.

[0440] [Equation 22] 0 < CG2 / (CT2+CT3) < 1

[0441] CG2 is the center spacing between the second and third lenses, and CT2 and CT3 are the center thicknesses of the second and third lenses. When mathematical expression 22 is satisfied, the concave radius of curvature of the sensor-side surface of the second lens (102) can be set, and the optical path between the second and third lenses (102, 103) can be set. Preferably, 0.2 < CG2 / (CT2+CT3) < 0.6 can be satisfied.

[0442] [Equation 23] 0 < CG4 / (CT4+CT5) < 1

[0443] CG4 is the center spacing between the fourth and fifth lenses, and CT4 and CT5 are the center thicknesses of the fourth and fifth lenses. When mathematical expression 23 is satisfied, the radius of curvature of the sensor-side surface of the fourth lens (104) can be reduced, and an optical path can be set according to the center spacing between the fourth and fifth lenses (104, 105). Preferably, 0 < CG4 / (CT4+CT5) < 0.5 can be satisfied.

[0444] [Equation 24] 1 < CG_max / CG4 < 5

[0445] CG_max refers to the maximum center spacing between lenses within the optical system. When mathematical expression 24 is satisfied, the maximum center spacing between lenses is positioned closer to the object than the center spacing between the fourth lens (104) and the fifth lens (105), thereby suppressing an increase in the size of the fourth lens (104). Preferably, 3 < CG_max / CG4 < 4 can be satisfied.

[0446] [Equation 25] 0.5 < CT5 / BFL < 2

[0447] When the central thickness of the fifth lens and the optical axis distance between the fifth lens (105) and the sensing unit (151) satisfy mathematical expression 25, the incident light can be stably transmitted to the entire area of ​​the sensing unit (151) by the fifth lens (105). Preferably, 0.7 < CT5 / BFL < 1.2 can be satisfied.

[0448] [Equation 26] 1 < CG3 / CT5 < 3

[0449] CG3 represents the center spacing between the third and fourth lenses, and CT5 represents the center thickness of the fifth lens. When mathematical expression 26 is satisfied, the effective diameter of the fifth lens (105) can be adjusted. Preferably, 1.2 < CG3 / CT5 < 2.2 can be satisfied.

[0450] [Equation 27] 0 < CG4 / CT5 < 1

[0451] CG4 represents the center spacing between the fourth and fifth lenses, and CT5 represents the center thickness of the fifth lens. When mathematical expression 27 is satisfied, the effective diameter of the fifth lens (105) can be adjusted, and the aberration characteristics in the center and peripheral parts of the sensing unit (151) can be improved. Preferably, 0.3 < CG4 / CT5 < 0.8 can be satisfied.

[0452] [Equation 28] 5 < L5R2 / CT5 < 30

[0453] L5R2 is the radius of curvature of the sensor-side surface of the fifth lens. When mathematical expression 28 is satisfied, the refractive power of the fifth lens (105) can be controlled and optical performance can be improved. Preferably, 10 < L5R2 / CT5 < 20 can be satisfied.

[0454] [Equation 29] 3 < L5R2 / L5R1 < 10

[0455] L5R1 is the radius of curvature of the object-side surface of the fifth lens. When mathematical expression 29 is satisfied, the refractive power of the fifth lens (105) can be controlled and optical performance can be improved. Preferably, 5 < L5R2 / L5R1 < 9 can be satisfied.

[0456] [Equation 30] 20 < L1R1 / L1R2 < 70

[0457] L1R1 is the radius of curvature of the object-side surface of the first lens, and L1R2 is the radius of curvature of the sensor-side surface of the first lens. When mathematical expression 30 is satisfied, the refractive power of the first lens (101) can be controlled and the optical performance can be improved. Preferably, 30 < L1R1 / L1R2 < 50 can be satisfied.

[0458] [Equation 31] 0 < |L2R1 / L2R2| < 2

[0459] L2R1 is the radius of curvature of the object-side surface of the second lens, and L2R2 is the radius of curvature of the sensor-side surface of the second lens. When mathematical expression 31 is satisfied, the refractive power of the second lens (102) can be controlled to improve optical performance, and the effective diameters of the sensor-side lenses of the second lens (102) can be adjusted. When the object-side surface of the second lens (112) is made flat, lens processing can be facilitated. Preferably, 1 < |L2R1 / L2R2| < 1.5 can be satisfied.

[0460]

[0461] [Equation 32] 0 < CT_Max / CG_Max < 2

[0462] In Equation 32, the maximum central thickness (CT_Max) among the lenses and the maximum gap (CT_Max) between adjacent lenses can be set. When Equation 32 is satisfied, the optical system can have good optical performance at the focal length of the set angle of view and can reduce TTL. Preferably, 0.5 < CT_Max / CG_Max < 1 can be satisfied.

[0463] [Equation 33] 0 < ΣCT / ΣCG < 2

[0464] 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 33 is satisfied, the optical system can have good optical performance at the focal length at the set angle of view, and can reduce the TTL. Preferably, 1 < ΣCT / ΣCG < 1.5 can be satisfied.

[0465] [Equation 34] 5 < ΣNd < 15

[0466] ΣNd represents the sum of the refractive indices at the d-line of each of the plurality of lenses. When mathematical expression 34 is satisfied, TTL can be controlled in an optical system (100) in which aspherical lenses and spherical lenses are mixed, and improved resolution can be achieved. In addition, when the number of spherical lenses is greater than the number of aspherical lenses, the sum of TTL and refractive indices can be set. Mathematical expression 34 can preferably satisfy 7 < ΣNd < 13.

[0467] [Equation 35] 10 < ΣVd / ΣNd < 50

[0468] ΣVd means the sum of the Abbe numbers of each of the plurality of lenses. When mathematical expression 35 is satisfied, the optical system (100) can have improved aberration characteristics and resolution. By setting the sum of the Abbe numbers and the sum of the refractive indices of the lenses in mathematical expression 35, the optical characteristics can be controlled, and preferably, 10 < ΣVd / ΣNd < 20 can be satisfied.

[0469] [Equation 36] 50 < ΣCT*n < 150

[0470] ΣCT is the sum of the central thicknesses of multiple lenses, and n is the number of lenses in the optical system. If mathematical expression 36 is satisfied, TTL can be controlled. Preferably, 70 < ΣCT*n < 120 can be satisfied.

[0471] [Mathematical Formula 37] 1 < CA11 / CA_Min < 5

[0472] CA11 is the effective diameter of the object-side first surface (S1) of the first lens, and CA_Min represents the minimum effective diameter among the object-side surfaces and the sensor-side surfaces of the lenses. When mathematical expression 37 is satisfied, the optical system can control incident light, maintain optical performance, and provide a slimmer module. Mathematical expression 38 can preferably satisfy 1 < CA11 / CA_Min < 3. Here, CA11 may be the maximum effective diameter, and the object-side third surface (S3) of the second lens (102) may have the minimum effective diameter.

[0473] [Equation 38] 2 < CA_Max / CG_Max < 4

[0474] CA_Max represents the maximum effective diameter among the lens surfaces, and CG_Max represents the maximum center spacing among the lenses. If Equation 38 is satisfied, the maximum center spacing is arranged within the range based on the maximum effective diameter, thereby reducing the TTL. Preferably, 2 < CA_Max / CG_Max < 3 can be satisfied.

[0475] [Equation 39] 0.5 < CA_Max / D1 < 1.5

[0476] When mathematical expression 39 is satisfied, the position of the optical filter (155) can be set based on the maximum effective diameter. Preferably, 0.5 < CA_max / D1 < 1 can be satisfied.

[0477] [Equation 40] 0.1 < CA_Min / CG_Max < 1

[0478] Mathematical expression 30 can reduce TTL by setting the minimum effective diameter of the lens surface and the maximum center spacing between lenses within the above range. Preferably, 0.2 < CA_Min / CG_Max < 0.8 can be satisfied.

[0479]

[0480] [Mathematical Formula 41] 1 < CA_max / (2*ImgH) < 5

[0481] Mathematical expression 41 can be set to the maximum effective diameter (CA_Max) and the diagonal length (2*ImgH) of the sensing unit (151), and if this is satisfied, the optical system can maintain good optical performance and a slim and compact sensor device can be set. Mathematical expression 41 can preferably satisfy 2 < CA_max / (2*ImgH) < 4.

[0482] [Equation 42] 1 < TD / CA_Max < 4

[0483] TD is the optical axis distance from the center of the object-side surface of the first lens (101) to the center of the sensor-side surface of the last lens (105). When mathematical expression 42 is satisfied, the total optical axis distance and maximum effective diameter of the lenses can be set, so that the size for good optical performance can be set. Mathematical expression 43 can preferably satisfy 1.5 < TD / CA_Max < 3.

[0484] [Equation 42-1]

[0485] SD < TD

[0486] The above SD is the optical axis distance from the position of the aperture to the surface of the sensing unit (151). Preferably, the condition of 1.5 < TD / SD < 2.5 can be satisfied.

[0487] [Equation 43]

[0488] 0 < F / L5R2 < 0.5

[0489] F is the effective focal length of the receiving optical system, and L5S2 is the radius of curvature of the sensor-side surface of the fifth lens (105). When mathematical expression 43 is satisfied, the effect on optical system reduction, for example, TTL, can be controlled by setting the effective focal length and the radius of curvature of the sensor-side surface of the last aspherical lens. Mathematical expression 43 can preferably satisfy 0 < F / L5R2 < 0.2.

[0490] [Equation 44] 0 < F / L1R1 < 0.5

[0491] In mathematical expression 44, the effective focal length of the receiving optical system and the radius of curvature of the object-side surface of the first lens (101) can be set to control the influence on the incident light and TTL. Mathematical expression 44 can preferably satisfy 0 < F / L1R1 < 0.1.

[0492] [Equation 45] 0 < EPD / L5R2 < 0.5

[0493] EPD refers to the size (mm) of the entrance pupil of the receiving optical system (100). When the receiving optical system (100) according to the embodiment satisfies mathematical expression 45, the optical system (100) can control the incident light. Preferably, the condition of 0 < EPD / L5R2 < 0.2 can be satisfied.

[0494] [Equation 46] 0 < EPD / L1R1 < 0.5

[0495] In mathematical expression 46, the size of the entrance pupil of the receiving optical system (100) and the radius of curvature of the object-side surface of the first lens (101) can be set, and when these are satisfied, the receiving optical system (100) can control the incident light. Preferably, the condition of 0 < EPD / L1R1 < 0.2 can be satisfied.

[0496]

[0497] [Equation 47] 0 < |F1 / F2| < 5

[0498] F1 is the focal length of the first lens (101), and F2 is the focal length of the second lens (102). When mathematical expression 47 is satisfied, the refractive power of the first and second lenses can be controlled to improve the resolution, and the TTL and effective focal length (EFL) can be affected. Preferably, the condition 0.5 < |F1 / F2| < 1 can be satisfied, or the condition |F1|< |F2| can be satisfied.

[0499]

[0500] [Equation 48] 0 < |F1| / F < 10

[0501] In mathematical expression 48, the focal length of the first lens (101) and the effective focal length of the optical system can be set, and the refractive power of the first lens (101) can be controlled to improve the resolution. Preferably, 0 < |F1| / F < 5 can be satisfied.

[0502] [Equation 49] 0 < |F1 / F5| < 5

[0503] In mathematical expression 49, the focal lengths of the first and fifth lenses (101, 105) can be set, and the refractive power of the first and fifth lenses (101, 105) can be controlled to improve the resolution. Preferably, 0 < |F1 / F5| < 1 can be satisfied.

[0504] [Equation 49-1] |F1|< F4

[0505] [Equation 49-2] F3 < F4

[0506] [Equation 49-3] F5 < F4

[0507] In mathematical expressions 49-1 to 49-3, F1 to F5 are the focal lengths of the first to fifth lenses (101 to 105), and light can be guided to the effective area of ​​the aspherical lens by adjusting the focal length of the spherical lens to the focal length of the last aspherical lens. Here, F1 is -5 mm or less, for example, in the range of -5 mm to -30 mm. F2 is -5 mm or less, for example, in the range of -5 mm to -30 mm. F3 is 8 mm or more, for example, in the range of 8 mm to 30 mm. F4 is 10 mm or more, for example, in the range of 10 mm to 36 mm. F5 is 8 mm or more, for example, in the range of 8 mm to 30 mm. The balance of the focal lengths of each lens can suppress the difference in focus position due to temperature change. Accordingly, it is possible to suppress the deterioration of the optical characteristics of the imaging lenses due to temperature change. Here, the aperture (ST) of the receiving optical system is arranged on the sensor-side surface of the third lens (103). The focal length of the lens arranged on the sensor-side surface closer to the aperture (ST) and closest to the aperture (ST) is greater than 0. In the embodiment of the present invention, the focal length F3 of the third lens (103) should be designed to be greater than 0. In this case, the third lens (103) collects light, so that the effective diameters of the fourth and fifth lenses, which are lenses arranged closer to the sensor than the third lens (103), can be prevented from increasing, and the TTL can be prevented from becoming longer, thereby enabling miniaturization of the receiving optical system. In this case, a wide-angle optical system can be provided in a field of view (FOV) exceeding 100 degrees, for example, in a range of 110 degrees to 130 degrees.

[0508]

[0509] [Equation 50] 0 < | F1 / F4| < 1

[0510] F1 is the refractive power value of the first lens (101), and F4 is the refractive power value of the fourth lens (104). That is, the refractive powers of the first and fourth lenses have opposite refractive powers, so that aberrations can be improved and light can be effectively guided by the aspherical lens. When the condition of F1 * F4 < 0 is satisfied, the improvement effect of chromatic aberration in the two lenses is not significant.

[0511] [Mathematical Formula 51] 20mm < TTL < 60mm

[0512] TTL (Total track length) refers to the distance (mm) from the center of the first surface (S1) of the first lens (101) to the upper surface of the sensing unit (151) on the optical axis (OA). In mathematical expression 51, the TTL can be set to be greater than 20 mm and less than 60 mm to provide a vehicle optical system. Mathematical expression 51 can preferably satisfy the condition of 30 mm < TTL < 55 mm or TD < TTL.

[0513] [Mathematical Formula 52] 2mm < ImgH < 20mm

[0514] Mathematical expression 52 can set the diagonal size (2*ImgH) of the sensing unit (151) and provide an optical system having a vehicle sensor size. Mathematical expression 52 can preferably satisfy 2 mm < ImgH < 5 mm.

[0515] [Mathematical Formula 53] 3mm < BFL < 7mm

[0516] In mathematical expression 53, the BFL (Back focal length) is set to be greater than 3 mm and less than 7 mm, so that the installation space of the cover glass (153) can be secured, the assemblability of the components can be improved through the gap between the sensing unit (151) and the last lens, and the joint reliability can be improved. Mathematical expression 53 can preferably satisfy 4 mm < BFL < 7 mm. When the BFL is less than the range of mathematical expression 53, some of the light traveling to the sensing unit may not be transmitted to the sensing unit, which may cause a decrease in resolution. When the BFL exceeds the range of mathematical expression 53, stray light may be introduced, which may deteriorate the aberration characteristics of the optical system.

[0517] [Mathematical Formula 54] 1mm < F < 10mm

[0518] Mathematical expression 54 can set the overall focal length (F) to suit the vehicle receiving optical system. Mathematical expression 54 can satisfy 1 mm < F < 5.5 mm.

[0519] [Mathematical Formula 55] 100 degrees < FOV

[0520] In mathematical expression 55, FOV (Field of view) means the angle of view (Degree) of the optical system (100), and a vehicle optical system having an angle of view (F0V) exceeding 100 degrees can be provided. Preferably, the FOV can satisfy 110 ≤ FOV ≤ 130. The range of the vehicle optical system can be set by the angle of view in mathematical expression 55. The sensor length in the horizontal direction is based on 6.04 mm ± 0.5 mm. In addition, when mathematical expression 55 is satisfied, when the temperature changes from room temperature to high temperature, the change rate of the effective focal length and the change rate of the angle of view can be set to 5% or less, for example, 0 to 5%. In addition, even if two or more aspherical lenses are mixed with spherical lenses in the optical system (100), the deterioration of optical characteristics can be prevented through temperature compensation and aberration correction by the aspherical lens made of glass.

[0521] [Mathematical Formula 56] 1 < TTL / CA_max < 7

[0522] Mathematical expression 56 establishes a 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 56 preferably satisfies 1 < TTL / CA_max < 3.

[0523]

[0524] [Equation 57] 10 < TTL / ImgH < 30

[0525] Mathematical expression 57 can set the total optical axis length (TTL) of the optical system and the diagonal length (ImgH) from the optical axis of the sensing unit (151). When the optical system (100) according to the embodiment satisfies Mathematical expression 57, the optical system (100) can have TTL for application to the vehicle sensing unit (151), thereby providing improved image quality. Mathematical expression 57 can preferably satisfy 10 < TTL / ImgH < 20.

[0526] [Equation 58] 1 < BFL / ImgH < 2

[0527] Mathematical expression 58 can set the optical axis distance between the sensing unit (151) and the last lens and the length in the diagonal direction from the optical axis of the sensing unit (151). When the optical system (100) according to the embodiment satisfies Mathematical expression 58, the optical system (100) can secure BFL for applying the size of the vehicle sensing unit (151), can set the distance between the last lens and the sensing unit (151), and can have good optical characteristics in the center and periphery of the field of view (FOV). Mathematical expression 58 can preferably satisfy 1.2 < BFL / ImgH < 1.8.

[0528] [Equation 58-1] ImgH < BFL < D1

[0529] BFL may be greater than a value (ImgH) that is half the diagonal length of the sensing unit (151) and less than the optical axis distance from the optical filter (155) to the surface of the sensing unit (151).

[0530] [Equation 59] 7 < TTL / BFL < 15

[0531] Mathematical expression 59 can set the total optical axis length (TTL) of the receiving optical system and the optical axis spacing (BFL) between the sensing unit (151) and the last lens. When the optical system (100) according to the embodiment satisfies Mathematical expression 59, the optical system (100) can secure BFL. Mathematical expression 59 can preferably satisfy 8 < TTL / BFL < 12.

[0532] [Equation 60] 0 < F / TTL < 0.5

[0533] Mathematical expression 60 can set the total focal length (F) and the total optical axis length (TTL) of the receiving optical system (100). Accordingly, an optical system for a driver assistance system can be provided. Mathematical expression 60 can preferably satisfy 0 < TTL / F < 0.1. When the optical system (100) according to the embodiment satisfies Mathematical expression 60, the optical system (100) can have an appropriate focal length in the set TTL range, and provides an optical system that can form an image while maintaining an appropriate focal length even when the temperature changes from low to high. When it is less than the lower limit of Mathematical expression 60, it is necessary to increase the refractive power of the lenses, making it difficult to correct spherical aberration or distortion aberration, and when it is more than the upper limit of Mathematical expression 60, the effective diameter or TTL of the lenses becomes long, which may cause a problem of a large-sized imaging lens system.

[0534] [Equation 61] 0 < F / BFL < 2

[0535] Mathematical expression 61 can set the total focal length (F) of the optical system (100) and the optical axis distance (BFL) between the sensing unit (151) and the last lens. When the optical system (100) according to the embodiment satisfies Mathematical expression 61, the optical system (100) can have a set angle of view and an appropriate focal length, and an optical system for a vehicle can be provided. In addition, the optical system (100) can minimize the distance between the last lens and the sensing unit (151), and thus can have good optical characteristics in the periphery of the field of view (FOV). Mathematical expression 61 can preferably satisfy 0.5 < F / BFL < 1.

[0536] [Equation 62] 0.5 < F / ImgH < 1.5

[0537] Mathematical expression 62 can set the total focal length (F, mm) of the optical system (100) and the diagonal length (ImgH) from the optical axis of the sensing unit (151). This optical system (100) can have improved aberration characteristics in the size of the vehicle sensing unit (151). Mathematical expression 62 can preferably satisfy 0.8 < F / ImgH < 1.4.

[0538] [Equation 63] 0.5 < F / EPD < 1.5

[0539] Mathematical expression 63 can set the overall focal length (F) and entrance pupil size of the receiving optical system (100). Accordingly, the overall brightness of the optical system can be controlled. Mathematical expression 63 preferably satisfies 0.5 < F / EPD < 1.

[0540] [Mathematical Formula 64] 0 < EPD / ImgH / FOV < 0.2

[0541] Mathematical expression 64 can set the relationship between the entrance pupil size (EPD), the length of half the maximum diagonal length of the sensing unit (ImgH), and the field of view. Accordingly, the overall size and brightness of the optical system can be controlled. Mathematical expression 64 can preferably satisfy 0 < EPD / ImgH / FOV < 0.1.

[0542] [Equation 65] 100 < FOV / F# < 200

[0543] Mathematical expression 65 can establish the relationship between the angle of view and the F number (F#) of the optical system. Mathematical expression 65 can preferably satisfy 120 < FOV / F# < 170. Here, F# is provided to be 1.2 or less, thereby providing a bright image.

[0544] [Equation 66] 50 < (CT_Max+CG_Max)*n < 150

[0545] [Mathematical Formula 67] 800 < (FOV*TTL) / n

[0546] Preferably, mathematical expression 67 can satisfy the condition of 1000 < (FOV*TTL) / n < 1300 depending on the angle of view and the number of lenses (n).

[0547] [Mathematical Formula 68] FOV < (TTL*n)

[0548] [Equation 69] 5 < (TD / CA_Max)*n < 30

[0549] Preferably, 8 < (TD / CA_Max)*n < 20 can be satisfied.

[0550] [Mathematical Formula 70] 0 < (CA52 / CA22) / (CA11 / CA22) < 1.5

[0551] In mathematical expressions 66 to 70, n represents the total number of lenses, and depending on the total number of lenses, the relationship between the maximum center thickness (CT_Max), maximum center spacing (CG_max), FOV, TTL, optical axis distance (TD) of the lenses, effective diameter (CA52) of the sensor-side surface of the fifth lens, effective diameter (CA11) of the object-side surface of the first lens, and effective diameters (CA21, CA22) of the object-side and sensor-side surfaces of the second lens can be set. Accordingly, the chromatic aberration, resolution, size, etc. of an optical system having 6 or fewer lenses can be controlled.

[0552]

[0553] The receiving optical system (100) according to the embodiment can satisfy at least one or two or more mathematical equations from mathematical equations 1 to 70. In this case, the receiving optical system (100) can have improved optical characteristics. Specifically, when the receiving optical system (100) satisfies at least one of mathematical equations 1 to 35 and / or at least one of mathematical equations 36 to 70, the receiving optical system (100) can have improved resolution and improve aberration and distortion characteristics. In addition, the receiving optical system (100) can secure a BFL (Back focal length) for applying a vehicle sensing unit (151), can compensate for optical characteristic degradation due to temperature change, and can minimize the gap between the last lens and the sensing unit (151), thereby having good optical performance at the center and periphery of the field of view (FOV).

[0554]

[0555] Table 5 shows the items of the mathematical formulas described above in the receiving optical system (100) of the embodiment, including the TTL (mm), BFL (mm), effective focal length (F), ImgH (mm), effective diameter (mm), sum of the center thicknesses of each lens, sum of the center spacings between adjacent lenses, TTL (mm), sum of Abbe numbers, sum of refractive indices, TD (mm), which is the optical axis distance from the first surface (S1) to the tenth surface (S10), focal lengths (F1, F2, F3, F4, F5), angle of view (degrees), edge thickness (ET), F number, etc. of each of the first to fifth lenses.

[0556] Item ValueItem ValueF(EFL)3.349ET15.613F1-9.909ET24.295F2-10.775ET32.502F314.869ET41.803F419.845ET51.903F515.271FOV1 28.810ΣNd8.786EPD3.516ΣVd133.500BFL4.176ΣCT20.567TD4.599ΣCG17.834ImgH41.586TTL43.0SD3.020F-number0.802

[0557]

[0558] Table 6 shows the result values ​​for the mathematical expressions 1 to 70 described above in the receiving optical system (100) of the embodiment. Referring to Table 6, it can be seen that the receiving optical system (100) satisfies at least one, two or more, or three or more of the mathematical expressions 1 to 35. In addition, it can be seen that the receiving optical system (100) satisfies at least one, two or more, or three or more of the mathematical expressions 36 to 70. In detail, it can be seen that the optical system (100) according to the embodiment satisfies at least one or two or more of the mathematical expressions 1 to 70, or all of the mathematical expressions. Accordingly, the receiving optical system (100) can have good optical performance and excellent optical characteristics at the center and periphery of the field of view (FOV).

[0559] Equation ValueEquation Value10 < CT1 / CT2 < 30.9383650 < ∑CT*n < 150102.83722 < CA11 / CT1 < 106.433372 < CA11 / CA_Min < 51.67830 < CT5 / CT4 < 30.848382 < CA_Max / CG_Max < 42.54840 < CT5 / (CT1+CT2) < 30.762390.5 < CA_Max / D1 < 1.50.84551 < CG3 / CT5 < 31.604400.1 < CA_Min / D1 < 10.50360 < CG4 / CG1 < 10.384411 < CA_Max / (2*ImgH) < 52.98272 < CG3 / CG4 < 53.447421 < TD / CA_Max < 42.30980.3 < CG3 / (CT1+CG1+CT2) < 1.50.635430 < F / L5R2 < 0.50.05495 ​​< TTL / CT_AVER < 2510.453440 < F / L1R1 < 0.50.011101.70 < Nd11.816450 < EPD / L5R2 < 0.50.067110 < Nd1 / Nd3 <1.51.000460 < EPD / L1R1 < 0.50.013120 < Nd3 / Nd4 <1.51.000470 < |F1 / F2| < 50.92013(Vd4*Nd4) < (Vd2*Nd2)Satisfied481 < |F1| / F < 102.95914BFL < D1Satisfied490 < |F1 / F5| < 50.64915CT5 < TTL / 3 < D1Satisfied500 < | F1 / F4| < 10.499160.5 < D1 / D2 < 1.5Satisfied5120 < TTL < 6043.000170 < OFt < CG3Satisfied522 < ImgH < 203.020181 < CA11 / CA21 < 51.678533 < BFL < 74.599190 < CA22 / CA31 < 20.837541 < F < 103.349200.5 < CA42 / CA51 < 21.23755100 < FOV128.810211 < CA11 / CA52 < 51.657561 < TTL / CA_max < 72.387220 < CG2 / (CT2+CT3) < 10.4135710 < TTL / ImgH < 3014.238230 < CG4 / (CT4+CT5) < 10.214581 < BFL / ImgH < 21.523241 < CG_Max / CG4 < 53.447597 < TTL / BFL < 159.350250.5 < CT5 / BFL < 20.958600 < F / TTL < 0.50.078261 < CG3 / CT5 < 31.604610 < F / BFL < 20.728270 < CG4 / CT5 < 10.465620.5 < F / ImgH < 1.51.109285 < L5R2 / CT5 < 3014.159630.5 < F / EPD < 1.50.802293 < L5R2 / L5R1 < 106.959640 < EPD / Imgh / FOV < 0.20.0113020 < L1R1 / L1R2 < 7040.19265100 < FOV / F# <200160.631310 < |L2R2 / L2R1| <21.1536650 < (CT_Max+CG_Max)*n < 15061.337320 < CT_Max / CG_Max < 20.73567800 < (FOV*TTL) / n1107.764330 < ∑CT / ∑CG < 21.15368FOV < (TTL*n)만족345 < ∑Nd <158.786695 < (TD / CA_max) *n < 3011.5443510 < ∑Vd / ∑Nd <5015.195700 < (CA52 / CA22) / (CA11 / CA21) < 1.50.562.

[0560]

[0561] FIG. 20 is a block diagram of a sensor system having a receiving optical system according to an embodiment of the invention. Referring to FIG. 20, the sensor system includes a control unit (10), a light source driving unit (20), a transmitting optical system (30), the receiving optical system (50) disclosed above, and a signal processing unit (60). The control unit (10) controls the transmission and reception of signals, and can be linked to devices related to communication services such as autonomous driving modules, artificial intelligence modules, drones, robots, augmented reality devices, virtual phenomenon devices, and 5G and 6G based on the transmitted / received signals. The light source driving unit (20) supplies power to and drives a light source included in the transmitting optical system (30). The light source generates a laser beam in the form of a line light source or a point light source. The light source driving unit (20) can adjust or vary the driving current supplied to the light source according to driving environment information. The driving environment information may include topographic information of the driving section, traffic congestion information, weather, etc. The wavelength of the laser beam generated from the light source may be in the range of 890 nm to 960 nm or in the range of 940 nm ± 10 nm. As another example, the wavelength of the laser beam may be 1550 nm ± 10 nm. The laser light source may be implemented as an InGaAs / GaAs-based semiconductor diode laser and may emit a high-power laser beam. The light source may include a single emitter and / or multiple emitters.

[0562] The above-mentioned transmitting optical system (30) transmits a laser beam generated from a light source to an object (40) through a lens and a diffuser, and the light reflected from the object (40) is received by the receiving optical system (50). The receiving optical system (50) may be composed of a plurality of optical sensors, and the optical sensors convert the received light into an electrical signal using a photodiode. That is, the sensing unit is arranged in a matrix type to convert the light received from the object scanned in each of the horizontal and vertical directions into a current. The signal processing unit (60) converts the output of the receiving optical system (50) into a voltage, amplifies it, and then converts the amplified signal into a digital signal using an analog-to-digital converter. The signal processing unit (60) analyzes digital data using a TOF (Time of Flight) algorithm or a phase-shift algorithm to detect the distance to the object (40) and the shape of the object.

[0563] 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.

[0564]

[0565] FIG. 21 is a drawing showing an example of measuring an object in a vehicle having the sensor system of the invention, and FIG. 22 is a drawing showing an example of surrounding surveillance in a vehicle having the sensor system of the invention.

[0566] Referring to FIGS. 21 and 22, a vehicle (202) having a sensor system includes a transmitting optical system that projects a laser beam (201) generated by a light source toward a target scene, and a receiving optical system that receives light (203) reflected from the target or subject (210). The sensor system also includes a lidar system, which typically includes a controller that calculates distance information to the subject (210) from the reflected light, and an element that can scan or provide a specific pattern of light, which may be a static pattern, within a desired range and field of view (FOV). The transmitting and receiving optical system is used to convert the received signal light into measurements representing a point-by-point three-dimensional map of the surrounding environment within the range and FOV of the lidar system.

[0567] 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.

[0568] Also shown is a schematic diagram illustrating the two-dimensional field of view and range requirements of a typical surround-view LIDAR system (200) for a vehicle (202). For example, adaptive cruise control may require a field of view and range (204) with a narrower field of view compared to the side-view "surround view" field of view and range (206), but with a longer range requirement. Typically, a vehicle's sensor functions may be enabled by a combination of LIDAR, radar, cameras, and ultrasonic sensors. The combination of these sensor data to generate information about the surrounding environment is often referred to as "sensor fusion." While the present invention describes a LIDAR system in the context of a vehicle, where LIDAR is widely used for autonomous, self-driving, or driver-assisted vehicles, it should be understood that the embodiments may be applied to any vehicle. Other types of vehicles may include robots, tractors, trucks, airplanes, unmanned aerial vehicles, boats, ships, and the like.

[0569] The features, structures, effects, etc. described in the embodiments above are included in at least one embodiment of the present invention, and are not necessarily limited to just one embodiment. Furthermore, the features, structures, effects, etc. illustrated in each embodiment can be combined or modified and implemented in other embodiments by a person having ordinary skill in the art to which the embodiments pertain. Therefore, the contents related to such combinations and modifications should be interpreted as being included in the scope of the present invention. In addition, although the embodiments have been described above, these are merely examples and do not limit the present invention. Those having ordinary skill in the art to which the present invention pertains will appreciate that various modifications and applications not illustrated above are possible without departing from the essential characteristics of the embodiments. For example, each component specifically shown in the embodiments can be implemented by modification. And the differences related to such modifications and applications should be interpreted as being included in the scope of the present invention defined in the appended claims.

Claims

1. First to fifth lenses aligned along the optical axis from the object toward the sensing unit; and An optical filter is disposed between the third lens and the fourth lens and is spaced apart from the sensing unit. The first to fifth lenses include aspherical lenses and spherical lenses having a number of lenses greater than the number of aspherical lenses, The optical axis distance from the optical filter to the surface of the sensing unit is D1, The optical axis distance from the sensor side of the fifth lens closest to the sensing unit to the surface of the sensing unit is BFL, Mathematical formula: BFL < D1 and satisfy, The effective diameter of the first lens is larger than the effective diameters of the remaining lenses, A receiving optical system in which the effective diameter of the fourth lens is smaller than the effective diameter of the first lens.

2. In paragraph 1, Includes an aperture arranged around the object side of the optical filter, The optical axis distance from the above aperture to the surface of the sensing unit is SD, Mathematical formula: 1 < SD / D1 < 1.2 A receiving optical system that satisfies .

3. In paragraph 1, The optical axis distance from the object side of the first lens to the optical filter is D2, Mathematical formula: 0.5 < D1 / D2 < 1.5 A receiving optical system that satisfies .

4. In any of the clauses 1 to 3, The above fourth lens and the above fourth lens are spherical lenses, The above second lens is an aspherical lens, The above fifth lens is an aspherical lens receiving optical system.

5. In paragraph 4, The above first lens is a spherical lens, The effective diameter of the fourth lens is larger than that of the first lens, The above effective diameter is the average of the effective diameters of the object-side and sensor-side surfaces of each lens in the receiving optical system.

6. In any one of paragraphs 1 to 3, The central thickness of the fifth lens is CT5, The optical axis distance from the center of the object-side surface of the first lens to the surface of the sensing unit is TTL, Mathematical formula: CT5 < TTL / 3 < D1 An optical system that satisfies .

7. In any one of paragraphs 1 to 3, The above optical filter is a band pass filter that passes the range of 890 nm to 960 nm, A receiving optical system in which the center spacing between the third lens and the fourth lens is the largest among the center spacings between the first lens to the fifth lens.

8. In any one of paragraphs 1 to 3, The first lens includes a convex object-side surface and a concave sensor-side surface on the optical axis, An optical system in which the effective diameter of the object-side surface of the first lens is the largest among the effective diameters of the lens surfaces from the first lens to the fifth lens.

9. In any one of paragraphs 1 to 3, The above third lens has a biconvex shape on the optical axis, The fourth lens has a convex meniscus shape toward the object on the optical axis, The fifth lens is a receiving optical system having a convex object-side surface and a concave sensor-side surface on the optical axis.

10. In any one of paragraphs 1 to 3, The above first lens has negative refractive power, The fifth lens has positive refractive power, The third and fourth lenses are receiving optical systems having positive refractive power.

11. In any one of paragraphs 1 to 3, Half of the diagonal length of the above sensing part is ImgH, The optical axis distance from the above optical filter to the surface of the sensing unit is D1, Mathematical formula: ImgH < BFL < D1 A receiving optical system that satisfies .

12. In paragraph 11, The optical axis distance from the surface of the first lens to the surface of the sensing unit is TTL, Mathematical formula: 20 mm < TTL < 60 mm, The first to fifth lenses are a receiving optical system made of glass.

13. A transmitting optical system having a light source and first to fourth lenses aligned with a first optical axis toward the light source from an object; and A receiving optical system comprising a sensing unit and a fifth to ninth lens aligned with a second optical axis toward the sensing unit from the object side, The fifth to ninth lenses include a spherical lens and an aspherical lens, In the above receiving optical system, the number of spherical lenses is greater than the number of aspherical lenses, The above receiving optical system includes an optical filter arranged between spherical lenses, The above transmission optical system includes a spherical lens and an aspherical lens, The number of aspherical lenses in the above transmission optical system is smaller than that of spherical lenses, The above transmitting optical system includes an aperture and a diffuser arranged on the object side relative to the first lens, The light-emitting area of ​​the above light source is different from the light-receiving area of ​​the above sensing unit, A lidar device wherein the first to fourth lenses and the fifth to ninth lenses are made of glass.

14. In paragraph 13, The first lens of the above transmitting optical system has a meniscus shape convex toward the object side and has positive power, The above third lens is a lidar device having positive power.

15. In paragraph 14, The fourth lens has a meniscus shape convex toward the object side and has negative power. A lidar device in which the effective diameter of the third lens is larger than the effective diameter of the fourth lens.

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