Optical system, sensor system and lidar device

Abstract

An optical system according to an embodiment of the present invention includes: a first lens to a fifth lens, which are arranged along the optical axis from an object toward a sensing unit; and an optical filter disposed in any one of the regions between the second lens and the fifth lens. The first lens has a meniscus shape convex toward the object on the optical axis. The object-side surface of the third lens has a concave shape on the optical axis. The radius of curvature of the object-side surface of the first lens on the optical axis is L1R1. The radius of curvature of the sensor-side surface of the first lens on the optical axis is L1R2. The mathematical expression 1 < L1R1 / L1R2 < 5 is satisfied.

Description

Technical Field

[0001] The embodiments relate to an optical system and sensor system for transmitting or receiving. Embodiments relate to a receiving optical system and a sensor system having the receiving optical system. Embodiments relate to a transmitting optical system and a sensor system having the transmitting optical system. Embodiments relate to a receiving optical system for LIDAR (Light Detection and Ranging) and an apparatus having the receiving optical system. Embodiments of the present invention relate to a mobile body having a receiving optical system and a system for LIDAR. Background Technology

[0002] ADAS (Advanced Driver Assistance Systems) is an advanced driver assistance system designed to assist the driver. It consists of sensing the situation ahead, determining the course of events based on the sensed information, and controlling the vehicle's behavior based on that determination. For example, ADAS sensors detect vehicles ahead and identify lanes. Subsequently, once the target lane, target speed, or target ahead is identified, the vehicle's ESC (Electronic Stability Control), EMS (Engine Management System), and MDPS (Motor Drive Power Steering) are controlled. Representative examples of ADAS implementations include automatic parking systems, low-speed city driving assistance systems, and blind spot warning systems.

[0003] With the recent increase in interest in autonomous vehicles, the demand for LIDAR (Light Detection and Ranging) sensors and core components is growing. Currently, LIDAR is only used in high-end, high-priced vehicles, but as manufacturing costs decrease, it is expected to be applied to general-purpose vehicles.

[0004] Because miniature and ultralight LiDAR technology is expected to be used not only as sensors for unmanned mobile devices, but also in satellites and aerospace for observing the Earth's terrain and environment, as well as in unmanned vehicles, transportation equipment, cranes, and robots used in factories and shipbuilding, and even in the form of combined or collaborative operations within mobile devices through integrated approaches across land, air, and marine industries, there is an urgent need to develop optical systems for miniature and ultralight LiDAR to enable these devices. Summary of the Invention

[0005] Technical issues

[0006] The embodiments provide an optical system with improved optical properties and a sensor system having the optical system. The embodiments provide a wide-angle optical system and a sensor system having the wide-angle optical system. The embodiments provide a receiving optical system, a sensor system, and a LIDAR device with improved thermal compensation characteristics. The embodiments provide a transmitting optical system, a sensor system, and a LIDAR device with improved thermal compensation characteristics.

[0007] Technical solution

[0008] The transmitting optical system according to an embodiment of the present invention includes: a first lens to a fifth lens aligned along the optical axis from an object toward a sensing unit; and an optical filter disposed in any one of the regions between the second lens and the fifth lens, wherein the first lens has a meniscus shape convex toward the object on the optical axis, the object-side surface of the third lens has a concave shape on the optical axis, the curvature radius of the object-side surface of the first lens on the optical axis is L1R1, the curvature radius of the sensor-side surface of the first lens on the optical axis is L1R2, and the mathematical expression: 1 < L1R1 / L1R2 < 5 can be satisfied.

[0009] According to an embodiment of the present invention, the object-side surface of the second lens on the optical axis may have a convex shape. The sensor-side surface of the fourth lens on the optical axis may have a convex shape. The sensor-side surface of the fifth lens on the optical axis may have a convex shape. Among the absolute values of the curvature radii of the object-side surfaces and the sensor-side surfaces of the first lens to the fifth lens, the curvature radius of the sensor-side surface of the fifth lens may be the largest.

[0010] According to an embodiment of the present invention, the optical filter may be disposed between two lenses having a center thickness greater than that of other lenses among the first lens to the fifth lens. The optical filter may be disposed between the third lens and the fourth lens.

[0011] According to an embodiment of the present invention, the optical axis distance from the optical filter to the surface of the sensing unit is DF2, and the optical axis distance from the sensor-side surface of the fifth lens to the surface of the sensing unit is BFL, and the mathematical expression: BFL < DF2 can be satisfied. The optical system includes an aperture stop disposed around the object-side surface of the optical filter or the sensor-side surface of the third lens, and the optical axis distance from the aperture stop to the surface of the sensing unit is SD, and the mathematical expression: 1 < SD / DF2 < 1.2 can be satisfied. The optical axis distance from the center of the object-side surface of the first lens to the optical filter is DF1, and the mathematical expression: DF2 < DF1 can be satisfied.

[0012] According to an embodiment of the present invention, the first lens to the fifth lens may be made of a glass material. The object-side surfaces and the sensor-side surfaces of the second lens and the fifth lens may be aspherical.

[0013] According to an embodiment of the present invention, the optical filter is a band-pass filter that passes through the range of 890 nm to 960 nm, and the center distance between the object-side lens and the sensor-side lens of the optical filter may be the largest among the center distances between the first lens and the fifth lens.

[0014] According to an embodiment of the present invention, the first and second lenses may have negative refractive power, and the third to fifth lenses may have positive refractive power. The center distance between the third and fourth lenses is CG3, and the thickness of the optical filter is OFt, which can satisfy the mathematical expression: 2 < CG3 / OFt < 15.

[0015] Beneficial effects

[0016] According to this embodiment, improved optical characteristics can be achieved. Specifically, in the optical system according to the embodiment, the bandpass filter can be positioned near the aperture stop to minimize the angle of incidence of light entering the optical filter. Therefore, the transmittance range of the bandpass filter can be widely utilized depending on the angle of incidence of light on the bandpass filter.

[0017] The receiving optical system of the LIDAR of the present invention can maximize the effect of receiving light emitted from the transmitting optical system. According to this embodiment, improved optical characteristics can be achieved. The LIDAR device of the present invention can maximize the extraction efficiency of light emitted from the transmitting / receiving optical system.

[0018] The receiving optical system of the LIDAR of the present invention can achieve good optical characteristics across a temperature range from low to high temperatures. Specifically, the multiple lenses included in the receiving optical system can have predetermined materials, refractive power, and refractive index. Therefore, if the refractive index of each lens changes due to temperature variations, and thus the focal length of each lens changes, mutual compensation can be achieved through the glass mold lens and the glass lens. That is, the optical system can effectively distribute refractive power across a temperature range from low to high temperatures and can prevent or minimize changes in optical characteristics within this range. Therefore, the optical system and sensor system according to the embodiments can maintain enhanced optical characteristics across various temperature ranges.

[0019] The lenses of the LIDAR optical system of the present invention can have a set thickness, refractive power, and distance between adjacent lenses. Therefore, the optical system and sensor system according to the embodiments can have enhanced MTF characteristics, aberration control characteristics, resolution characteristics, etc. within a set field of view, and can have good optical performance at the periphery of the field of view.

[0020] The optical system and sensor system according to the embodiments can achieve excellent optical characteristics while satisfying a set field of view through a combination of glass mold lenses and glass lenses. Therefore, the optical system can provide a thinner sensor system for vehicles. Thus, the optical system and sensor system can be provided for a variety of applications and devices, and can provide excellent optical characteristics even when exposed to harsh temperature environments, such as the exterior or interior of a vehicle at high temperatures during summer. Attached Figure Description

[0021] Figure 1 This is a side cross-sectional view of the receiving optical system of a LIDAR according to an embodiment.

[0022] Figure 2 It is shown Figure 1 The table shows the lens characteristics of the optical system.

[0023] Figure 3 It is shown Figure 1 A table of aspherical coefficients of lenses in an optical system.

[0024] Figure 4 It is about Figure 1 Data on the distortion characteristics of the optical system.

[0025] Figure 5 It shows about in Figure 1 The curves of the diffraction MTF (modulation transfer function) data of the optical system at low temperature, room temperature and high temperature.

[0026] Figure 6 It shows about Figure 1 A graph showing the aberration characteristics of the optical system at low temperatures.

[0027] Figure 7 It shows about Figure 1 A graph showing the aberration characteristics of the optical system at room temperature.

[0028] Figure 8 It shows about Figure 1 A graph showing the aberration characteristics of the optical system at high temperatures.

[0029] Figure 9 This comparison is made when the incident angle of the main beam, measured by an automated optical inspection (AOI) device, is 0 degrees, 20 degrees, and 40 degrees. Figure 1 The graph shows the transmittance curve of the filter in the optical system.

[0030] Figure 10 It is shown that has Figure 1 A block diagram of the sensor system for the optical system.

[0031] Figure 11 This is a side cross-sectional view of the transmitting optical system of a LIDAR according to an embodiment.

[0032] Figure 12 It is shown Figure 11 A diagram of the first lens and diffuser of the optical system.

[0033] Figure 13 It is a comparison about passing Figure 11Figures showing comparative examples and embodiments of the light refraction characteristics of the lens array of the diffuser in the transmitting optical system.

[0034] Figure 14 It is shown Figure 11 The table shows the lens characteristics of the optical system.

[0035] Figure 15 It is shown Figure 11 A table of aspherical coefficients of lenses in an optical system.

[0036] Figure 16 It shows about in Figure 11 The optical system is plotted based on the diffraction MTF data at low temperature, room temperature, and high temperature.

[0037] Figure 17 It shows about Figure 11 A graph showing the aberration characteristics of the optical system at low temperatures.

[0038] Figure 18 It shows about Figure 11 A graph showing the aberration characteristics of the optical system at room temperature.

[0039] Figure 19 It shows about Figure 11 A graph showing the aberration characteristics of the optical system at high temperatures.

[0040] Figure 20 It is about Figure 11 Data on the distortion characteristics of the optical system.

[0041] Figure 21 It is shown in Figure 11 A graph showing the pixel unit matching results based on the light source height and divergence angle in the transmitting optical system.

[0042] Figure 22 It is shown in Figure 1 A graph showing the pixel unit matching results based on image height and field of view in the receiving optical system.

[0043] Figure 23 This is a diagram illustrating an example of measuring an object in a vehicle equipped with the sensor system of the present invention.

[0044] Figure 24 This is a diagram illustrating an example of ambient environment monitoring in a vehicle equipped with the sensor system of the present invention. Detailed Implementation

[0045] Preferred embodiments of the invention will be described in detail below with reference to the accompanying drawings. The spirit of the invention is not limited to the embodiments described, and it can be implemented in various other forms. Furthermore, within the scope of the spirit of the invention, one or more components may be selectively combined and substituted for use. Additionally, unless explicitly defined and described, the terminology used in the embodiments of the invention (including technical and scientific terms) is to be interpreted as having the meaning commonly understood by one of ordinary skill in the art to which this invention pertains, and common terms such as those defined in dictionaries should be interpreted in light of the contextual meaning of the relevant art.

[0046] The terminology used in the embodiments of this invention is for explaining the embodiments and is not intended to limit the invention. In this specification, the singular form may also include the plural form unless specifically stated otherwise in the phrase, and where a statement of at least one (or more) of A and / or B, C may include one or more of all combinations that can be combined with A, B, and C. In describing components of embodiments of the invention, terms such as first, second, A, B, (a), and (b) may be used. Such terms are used only to distinguish the component from other components and may not be determined by the nature, order, or process of the corresponding constituent elements. Furthermore, when describing a component as being “connected,” “coupled,” or “joined” to another component, the description may include not only direct connection, coupling, or joining to another component, but also “connected,” “coupled,” or “joined” to another component through the connection between the component and the other component. Additionally, when described as being formed or disposed “above” or “below” each component, the description includes not only when the two components are in direct contact with each other, but also when one or more other components are formed or disposed between the two components. Additionally, when expressed as "above" or "below", it can refer to the downward and upward directions relative to a component.

[0047] In the description of this invention, "object-side surface" can refer to the surface of the lens facing the object side relative to the optical axis OA, and "sensor-side surface" can refer to the surface of the lens facing the imaging surface (sensing unit) relative to the optical axis. A convex surface of the lens can refer to a convex shape in the optical axis or paraxial region, and a concave surface of the lens can refer to a concave shape in the optical axis or paraxial region. The radius of curvature, center thickness, and optical axis distance between lenses listed in the lens data table can refer to values ​​(in mm) on the optical axis. "Vertical direction" can refer to a direction perpendicular to the optical axis, and the end of the lens or lens surface can refer to the end of the effective area of ​​the lens through which the incident light passes. Depending on the measurement method, the effective diameter of the lens surface can have a measurement error up to ±0.4 mm. The paraxial region refers to a very narrow region close to the optical axis, and is a region where the distance of the light ray from the optical axis OA is almost zero. In the following text, the term optical axis can include the center of each lens or a very narrow region near the optical axis.

[0048] Figure 1 This is a side cross-sectional view showing the receiving optical system of the present invention.

[0049] refer to Figure 1 The optical system 100 and the sensor system including it can be installed inside or outside the vehicle to monitor the driver or sense external objects or lanes. The material of each lens in the lens can be chosen to be glass or plastic, and the linear expansion coefficient of the lens is smaller for glass than for plastic. Therefore, glass lenses are used to suppress changes in the focal position due to temperature variations. However, if the optical system is composed of spherical glass lenses, there are limitations on reducing the number of lenses, and also limitations on reducing size and weight.

[0050] The optical system 100 of this embodiment is a receiving optical system and may include spherical lenses and aspherical lenses. Here, a spherical lens is a lens in which at least one or both of the object-side surface and the sensor-side surface of the lens are spherical. An aspherical lens is a lens in which at least one or both of the object-side surface and the sensor-side surface of the lens are aspherical. The optical system 100 may include spherical glass lenses and aspherical glass lenses. In addition, because aspherical lenses are used, the total length (TTL) of the optical system 100 can be reduced, and good correction of various aberrations such as spherical aberration and chromatic aberration is possible due to the aspherical lenses. In addition, aspherical lenses can minimize distortion in the peripheral region of the sensing unit 151. The optical system 100 may include n lenses, where the nth lens is the last lens adjacent to the sensing unit 151, and the (n-1)th lens is the lens closest to the last lens. n is an integer greater than or equal to 4, for example, in the range of 4 to 7 or 4 to 6. The ratio of spherical lenses to aspherical lenses among the n lenses can be any one of 3:1, 4:1, 3:2, 2:3, 3:3, 5:2, or 4:2.

[0051] In the optical system 100, the first lens 101 closest to the object can be made of glass. Glass material undergoes slight expansion and contraction due to external temperature changes, and its surface is not easily scratched, thus preventing surface damage. Therefore, in the optical system 100, the first lens 101 on the object side can be a spherical lens, and the nth lens can be an aspherical lens. Because the nth lens in the optical system 100 is an aspherical lens, various aberrations can be corrected for the incident light from the sensing unit 151.

[0052] Because at least two lenses closest to the object within the optical system 100 are made of glass, the rate of contraction and expansion due to temperature changes is less than that of plastic materials, thus preventing degradation of optical properties caused by temperature changes within the lens barrel. Furthermore, the optical system 100 includes a lens 105 disposed within the glass mold material closest to the sensing unit 151. Therefore, the rate of contraction and expansion due to temperature changes in lens 105 is lower than that of plastic materials, further preventing degradation of optical properties caused by temperature changes within the lens barrel.

[0053] Each lens 101-105 may have an object-side surface and a sensor-side surface. The object-side surface and the sensor-side surface are the two lens surfaces of the lens. The optical system 100 may include a spherical lens on the object side and a spherical lens on the sensor side, as well as an aspherical lens on the object side and an aspherical lens on the sensor side. In the optical system, the number of aspherical lenses may be less than the number of spherical lenses. Because the aspherical lenses are placed adjacent to the sensing unit 151, the aspherical lenses are able to correct various aberrations of the optical system 100. The spherical lenses and aspherical lenses may be made of glass material. Among the lenses of the optical system 100, the lens with the highest refractive index may be a spherical lens, and the lens with the highest Abbe number may be an aspherical lens. Because the first lens 101 has a high refractive index and is positioned adjacent to the object, the first lens 101 may have a thin center thickness CT1, and its effective diameter on the sensor side may be smaller than its effective diameter on the object side.

[0054] The first lens 101 has a lens surface with the largest effective diameter within the optical system 100. The lens with the smallest effective diameter within the optical system 100 can be located between the aperture stop ST and the first lens 101. Furthermore, the effective diameter of the aspherical lens can be smaller than that of the spherical lens. Here, the effective diameter of the lens is the average of the effective diameter on the object side and the effective diameter on the sensor side of each lens. The optical system 100 can be miniaturized by adjusting the effective diameter of each lens. Each of the lenses 101-105 can include an effective region and an ineffective region. The effective region can be the area through which incident light passes on each lens. That is, the effective region can be defined as the effective area or effective diameter where incident light is refracted to achieve optical properties. The ineffective region can be placed around the periphery of the effective region. The ineffective region can be a region from which no effective light is incident from multiple lenses. That is, the ineffective region can be a region unrelated to optical properties. Additionally, the end of the ineffective region can be a region fixed to a lens barrel (not shown) or the like that housing the lens.

[0055] Among the lenses in the optical system 100, the lens with the maximum center thickness can be a spherical lens. Among the lenses in the optical system 100, the lens with the maximum edge thickness can also be a spherical lens. The average center thickness of the aspherical lenses can be less than the average center thickness of the spherical lenses disposed between the aspherical lenses. Aspherical lenses with thin thickness can reduce the total top length (TTL) and refract incident light along various paths. Here, TTL is the distance along the optical axis OA from the center of the object-side surface of the first lens 101 to the image surface of the sensing unit 151. Within the optical system 100, TTL can be greater than 10 times ImgH, for example, greater than 10 times and less than 30 times. ImgH is the distance from the center of the effective area of ​​the sensing unit 151 to the diagonal end, or half the maximum diagonal length of the effective area of ​​the sensing unit 151. Within the optical system 100, the effective diameter of each lens can be greater than the diagonal length of the sensing unit 151.

[0056] The effective focal length of the optical system 100 can be shortened to 10 mm or less to achieve a wide angle. The effective focal length (EFL) of the optical system 100 can be 10 mm or less, for example, in the range of 1 mm to 10 mm or in the range of 1 mm to 6 mm. Because the effective focal length is 10 mm or less and the field of view (FOV) is provided to be greater than 100 degrees, the optical system 100 can be provided as a standard receiving optical system in an onboard sensor system. For example, the receiving optical system and sensor system according to the embodiment can be applied to sensing devices for ADAS (Advanced Driver Assistance Systems) installed inside or outside a vehicle.

[0057] Optical system 100 can have TTL / (2 The condition (ImgH) is greater than 5, for example, within the range of greater than 5 and less than or equal to 10. Therefore, the center thickness of each lens along the optical axis OA can be increased and the size of the sensing part 151 can be reduced, thereby providing an automotive lens optical system. In addition, for use in a motor vehicle camera, temperature compensation must be applied within the temperature range used as a temperature reliability evaluation standard for motor vehicle electronic components, i.e., -45°C to +120°C. That is, the lens must be configured such that the lens focal point remains within the set range even when the lens expands or contracts due to temperature changes. Within the optical system 100, the number of lenses with positive (+) refractive power or power can be equal to or greater than the number of lenses with negative (-) refractive power or power. The number of lenses with positive (+) refractive power or power can be 50% or more of the total number of lenses. Because this optical system 100 is a mixture of spherical and aspherical lenses made of glass material, various aberrations can be corrected, thereby preventing a decrease in optical performance.

[0058] An optical system according to an embodiment of the present invention will be described.

[0059] Figure 1 This is a side cross-sectional view of the receiving optical system of a LIDAR according to an embodiment. Figure 2 It is shown Figure 1 A table of lens characteristics for an optical system. Figure 3 It is shown Figure 1 A table of aspherical coefficients of lenses in a receiving optical system. Figure 4 It is about Figure 1 The data on the distortion characteristics of the receiving optical system Figure 5 It shows about in Figure 1 The curves of the diffraction MTF (modulation transfer function) data from the receiving optical system at low temperature, room temperature, and high temperature are shown. Figure 6 It shows about Figure 1 A graph showing the aberration characteristics of an optical system at low temperatures. Figure 7 It shows about Figure 1 The graph shows the aberration characteristics of the optical system at room temperature. Figure 8 It shows about Figure 1 A graph showing the aberration characteristics of the optical system at high temperatures.

[0060] refer to Figures 1 to 3 The optical system 100 may include first lenses 101 to fifth lenses 105, which are aligned with the optical axis OA from the object towards the sensor side. First to fifth lenses 101-105 can be defined as lens portions. The optical system 100 may include an optical filter 155, which may be disposed between the lenses. The optical filter 155 may be disposed between aspherical lenses. The optical filter 155 may be disposed between spherical lenses. The optical filter 155 may be disposed at a position closer to the spherical lenses than the aspherical lenses. Light corresponding to the information of the object passes through first lenses 101 to third lenses 103, the optical filter 155, and fourth lenses 104 and fifth lenses 105, and may be incident on the sensing unit 151.

[0061] The first lens 101 may have positive (+) or negative (-) refractive power along the optical axis OA, and preferably, it may have negative (-) refractive power. The first lens 101 may comprise a plastic material or a glass material; for example, it may be a glass material. A first lens 101 made of glass material can reduce changes in center position and radius of curvature, etc., caused by temperature variations in the surrounding environment, and can protect the incident-side surface of the optical system 100. The first lens 101 is a non-injection molded glass material.

[0062] On the optical axis OA, the first surface S1 on the object side of the first lens 101 can have a convex shape, and the second surface S2 on the sensor side can have a concave shape. That is, the first lens 101 can have a meniscus shape convex toward the object. The first surface S1 and the second surface S2 can have a spherical shape. Alternatively, on the optical axis OA, the first surface S1 can have a concave shape, and the second surface S2 can have a convex shape. Alternatively, the first lens 101 can have concave shapes on both sides.

[0063] Because the first surface S1 of the first lens 101 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 edge distance between the first lens 101 and the second lens 102 can be reduced, and the effective diameter of the second lens 102 can be reduced. The increase in the effective diameter of the second lens 102 can be suppressed by the shape of the lens surface of the first lens 101.

[0064] If the refractive index of the first lens 101 is Nd1, then the following condition can be satisfied: 1.7 < Nd1 or 1.75 < Nd1 < 2.1. Because 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 made easier. If the refractive index (Nd1) of the first lens 101 is less than this condition, then the lens surface must be formed to be sharply concave or convex to increase the refractive power of the second lens 102. In this case, lens manufacturing is not easy, the lens defect rate increases, and it may lead to a decrease in production output.

[0065] The second lens 102 can be disposed between the first lens 101 and the third lens 103. The second lens 102 can have positive (+) or negative (-) refractive power on the optical axis OA; for example, it can have negative (-) refractive power. The second lens 102 can comprise a plastic or glass material; for example, it can be provided as a glass material. The second lens 102 can be injection molded. On the optical axis OA, the object-side third surface S3 of the second lens 102 can have a convex shape, and the sensor-side fourth surface S4 can have a concave shape. That is, the second lens 102 can have a meniscus shape convex toward the object. The third surface S3 and the fourth surface S4 can be aspherical and, as... Figure 4As shown, it can be defined as L2S3 and L2S4, and can have a conic constant (K) and aspherical coefficients from the 4th to the 14th order (A to F). The third surface S3 can have a critical point at the end or edge of the effective area on the optical axis OA. Since the third surface S3 has a convex shape on the optical axis OA and has a critical point, the edge of the third surface S3 can protrude further toward the object than the center of the third surface S3. The fourth surface S4 can be set without a critical point from the optical axis OA to the edge. Alternatively, on the optical axis OA, the third surface S3 can be convex and the fourth surface S4 can be concave. Alternatively, the second lens 102 can have a convex shape on both sides. A critical point is 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 can mean a point where the slope value is 0. Additionally, a critical point can be a point where the slope value of the tangent passing through the lens surface increases and then decreases or decreases and then increases.

[0066] If the refractive index of the second lens 102 is Nd2, the following condition can be satisfied: 1.8 > Nd2 or 1.55 < Nd2 < 1.8. The refractive index (Nd2) of the second lens 102 is lower than the refractive indices of the first lens 101 and the third lens 103, and the difference in the radius of curvature between the third surface S3 and the fourth surface S4 can be provided as 30 mm or more. Therefore, the second lens 102 can refract the 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 has a critical point, it can refract the incident light rays to the entire area of the fourth surface S4. Additionally, since the fourth surface S4 on the sensor side of the second lens 102 is concave and has a small radius of curvature, an increase in the distance between the second lens 102 and the third lens 103 can be prevented.

[0067] The third lens 103 may have positive (+) or negative (-) refractive power on the optical axis OA; for example, it may have positive (+) refractive power. The third lens 103 may comprise a plastic or glass material; for example, it may be a glass material. The third lens 103 is a non-injection molded glass material. On the optical axis OA, the object-side surface S5 of the third lens 103 may have a concave shape, and the sensor-side sixth surface S6 may have a convex shape. That is, the third lens 103 may have a meniscus shape convex toward the sensing unit 151 or the image sensor on the optical axis OA. At least one or both of the fifth surface S5 and the sixth surface S6 of the third lens 103 may be spherical. At least one or both of the fifth surface S5 and the sixth surface S6 may be configured to have no critical point from the end of the optical axis OA to the effective region. Alternatively, the third lens 103 may have a meniscus shape convex toward the object. Or, the third lens 103 may have a shape that is concave or convex on both sides of the optical axis. If the refractive index of the third lens 103 is Nd3, then the following condition can be satisfied: Nd2 < Nd3. If the Abbe number of the third lens 103 is Vd3, then the following condition can be satisfied: Vd3 < Nd2. Here, Vd2 is the Abbe number of the second lens 102.

[0068] Optical system 100 may include an aperture stop ST. The aperture stop ST can control the amount of light incident on optical system 100. The aperture stop ST can be positioned around the periphery between two adjacent lenses. The aperture stop ST can be positioned around the periphery of the sensor-side surface S6 of the third lens 103. The aperture stop ST can be positioned around the periphery between the third lens 103 and the fourth lens 104. The aperture stop ST can be positioned around 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 stop ST can be positioned around the periphery of the object-side surface or sensor-side surface of the optical filter 155. The aperture stop ST can be positioned around the periphery between the third lens 103 and the optical filter 155. The aperture stop ST can be positioned around the periphery of the object-side surface FS1 of the optical filter 155. The lens surface on which the aperture stop ST is positioned, i.e., the sixth surface S6, enables more effective control and guidance of the amount of light in optical system 100. As in this embodiment, the aperture stop ST can be positioned on the sensor-side surface of the third lens 103. Alternatively, the aperture stop ST can be positioned around the object-side surface or sensor-side surface of the second lens 102. Alternatively, at least one lens selected from a plurality of lenses on the object-side surface or sensor-side surface of the third lens 103 can perform the function of the aperture stop.

[0069] The focal length of the third lens 103 is F3, satisfying the condition: F3 > 0. Because the third lens 103, positioned on the object side of the aperture stop ST, has positive refractive power, it can refract incident light along the optical axis and suppress the increase in the effective diameter of the lens on the sensor side or rear side of the third lens 103. Therefore, the third lens 103 can prevent a decrease in the output of the optical system and improve production efficiency. Here, the focal lengths of the fourth lens 104 and the fifth lens 105, positioned on the sensor side of the aperture stop ST, can be positive, and the optical system 100 can reduce the TTL within the field of view.

[0070] Because the sixth surface S6 on the sensor side of the third lens 103 has a convex shape and a radius of curvature smaller than that of the fifth surface S5, the center distance between the third lens 103 and the aperture stop ST can be smaller than the center distance between the aperture stop ST and the fourth lens 104. The effective diameter of the optical filter 155 can be larger than the effective diameter of the third lens 103. The optical filter 155 transmits the laser beam emitted from the transmitting optical system of the LIDAR device and reflected by the subject, while blocking beams of other wavelengths. To improve the efficiency of light blocking and transmission, the optical filter 155 can be positioned closer to the third lens 103 than the fourth lens 104.

[0071] The fourth lens 104 may have positive (+) or negative (-) refractive power on the optical axis OA; for example, it may have positive (+) refractive power. The fourth lens 104 may comprise plastic or glass material and may be provided as glass. The fourth lens 104 may not be injection molded. On the optical axis OA, the object-side surface S7 of the fourth lens 104 may have a convex shape, and the sensor-side eighth surface S8 may have a convex shape. The fourth lens 104 may have convex shapes on both sides. At least one or both of the seventh surface S7 and the eighth surface S8 may be spherical. The seventh surface S7 and the eighth surface S8 of the fourth lens 104 may be configured to have no critical point from the end of the effective region on the optical axis OA. Alternatively, the fourth lens 104 may have a meniscus shape convex toward the object. Alternatively, the fourth lens 104 may have a meniscus shape convex toward the image sensor. Alternatively, the fourth lens 104 may have a shape concave on both sides on the optical axis OA.

[0072] The fifth lens 105 may have positive (+) or negative (-) refractive power on the optical axis OA; for example, it may have positive (+) refractive power. The fifth lens 105 may comprise a plastic or glass material, and may be provided as a glass material. The fifth lens 105 may be injection molded. On the optical axis OA, the ninth surface S9 on the object side of the fifth lens 105 may have a convex shape, and the tenth surface S10 on the sensor side may have a convex shape. The fifth lens 105 may have a convex shape on both sides of the optical axis OA. Alternatively, the fifth lens 105 may have a meniscus shape convex toward the object or image sensor. Alternatively, the fifth lens 105 may have a concave shape on both sides of the optical axis OA. At least one or both of the ninth surface S9 and the tenth surface S10 may be aspherical. The aspheric coefficients of the ninth surface S9 and the tenth surface S10 may be provided as follows: Figure 3 L5S9 and L5S10. The ninth surface S9 of the fifth lens 105 can be set to have no critical point from the end of the effective area from the optical axis. The tenth surface S10 can have at least one critical point from the end or edge of the effective area from the optical axis, and the critical point can be positioned closer to the edge than the center of the tenth surface S10. The fifth lens 105 has an aspherical shape and is capable of guiding light incident through the fourth lens 104, which is a spherical lens, to the sensing unit 151.

[0073] If the refractive index of the fifth lens 105 is Nd5, then the condition Nd5 < Nd3 can be satisfied. If the Abbe number of the fifth lens 105 is Vd5, then the condition Vd3 < Vd5 can be satisfied. If the refractive index of the fourth lens 104 is Nd4, then the condition 0.8 < Nd4 / Nd5 < 1.2 can be satisfied. The fifth lens 105 can be an aspherical lens closest to the sensing unit 151. Aberrations such as spherical aberration and chromatic aberration can be improved by using a lens surface with an aspherical surface, and the effect on resolution can be controlled. Optical performance can be improved by using an aspherical surface of the lens surface adjacent to the sensing unit 151, for example, by improving aberration characteristics and preventing a reduction in resolution. At least one or both of the object-side surface and sensor-side surface of the second lens 102 and the fifth lens 105 can have freeform surfaces, i.e., non-rotationally symmetric surfaces.

[0074] The optical system 100 or sensor system may include a sensing unit 151. The sensing unit 151 is capable of sequentially detecting light that has passed through the lens. The sensing unit 151 is capable of detecting light and converting it into an electrical signal. The sensing unit 151 obtains various information about the subject. The sensing unit 151 is capable of detecting time delay or phase difference information with the incident light, and based on this, obtains distance information to the subject, position information of the subject, depth image of the subject, etc. For this purpose, the sensing unit 151 includes an image sensor or a photon detector, and may include sensors such as SPD (Synchronous Photodetector), SPAD (Single Photon Avalanche Diode), or APD (Avalanche Photodiode). As another example, the sensing unit 151 may include an element capable of detecting incident light, such as CCD (Charge-Coupled Device) or CMOS (Complementary Metal-Oxide-Semiconductor), as an image sensor. As another example, the sensing unit may include a TDC (Time-to-Digital Converter). 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 with an effective diameter greater than the effective length of the sensing unit 151 is 4 to 6, and there may be no number of lenses with an effective diameter less than the effective length of the sensing unit 151.

[0075] The first lens 101 and the third lens 103 can be made of the same material or have the same refractive index. The first lens 101 and the second lens 102 can have negative refractive power, and the third lens 103 to the fifth lens 105 can have positive refractive power. If the lens with negative refractive power or power is the first lens group and the lens with positive refractive power or power is the second lens group, then the aperture stop ST and the optical filter 155 can be placed within the second lens group. The aperture stop ST and the optical filter 155 can be positioned between the spherical lens surfaces of the second lens group.

[0076] The fifth lens 105 may have a lower refractive index than the first lens 101, the second lens 102, and the third lens 103, and may have a higher Abbe number than the first lens 101 and the third lens 103. The Abbe number of the fifth lens 105 may be lower than the Abbe number of the second lens 102. The effective diameter of the fifth lens 105 may be smaller than the effective diameter of the fourth lens 104. The effective diameter of the first lens 101 may be the largest among the lenses. The effective diameters of the second lens 102, the third lens 103, and the fourth lens 104 may be larger, and the lenses may be closer to the sensing unit 151. The effective diameter of the first lens 101 may be larger than the effective diameter of the fifth lens 105, which is closest to the sensing unit 151. Therefore, the brightness of the optical system 100 can be controlled. By controlling the effective diameter of each lens 101-105, the optical system 100 can control the incident light to compensate for the degradation of optical properties caused by changes in resolution and temperature, improve chromatic aberration control characteristics, and improve the vignetting characteristics of the optical system 100.

[0077] At least two lenses can be disposed between the optical filter 155 and the sensing unit 151. A fourth lens 104 and a fifth lens 105 can be disposed between the optical filter 155 and the sensing unit 151. Spherical and aspherical lenses can be disposed between the optical filter 155 and the sensing unit 151. The optical filter 155 can be disposed between the sixth surface S6 on the sensor side of the third lens 103 and the seventh surface S7 on the object side of the fourth lens 104. The optical filter 155 can be a bandpass filter that allows laser beams in the range of 890 nm to 960 nm or 940 nm ± 10 nm to pass through. As another example, the optical filter 155 can transmit in the range of 1550 nm ± 10 nm and block other wavelengths. The optical filter 155 allows wavelengths corresponding to the laser beam transmitted from the transmitting optical system of the LIDAR device to pass through and blocks light corresponding to the remaining ambient light. The optical filter 155 can be a bandpass filter.

[0078] The cover glass 153 is positioned between the final lens and the sensing unit 151, protecting the upper part of the sensing unit 151 and preventing a decrease in the reliability of the sensing unit 151. The cover glass 153 can be positioned between the fifth lens 105 and the sensing unit 151. The cover glass 153 can be removed. The cover glass 153 can be a protective glass.

[0079] Optical filter 155 is capable of allowing light of a specific wavelength to pass through and blocking the remaining light. Optical filter 155 can actively perform filtering operations. For this purpose, optical filter 155 may include an active device that, in response to an external control signal, allows only light with a center wavelength of a specific wavelength to pass through and blocks other wavelengths of light. The control signal given to optical filter 155 may include information about the center wavelength of the light passing through the active device, where this center wavelength may correspond to the center wavelength of the light emitted from the transmitting optical system. Therefore, the control signal given to optical filter 155 is a control signal that matches the center wavelength of the light emitted from the transmitting optical system with the center wavelength of the light to pass through the active device of optical filter 155. Due to the active device included in optical filter 155, optical filter 155 can selectively allow only the desired light to pass through 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 an active device, optical filter may include a tunable bandpass filter. The operation method of a tunable bandpass filter may be liquid crystal or acousto-optic.

[0080] The third lens 103 is positioned on the object side of the optical filter 155 and may have a refractive index greater than that of the second lens 102 and a center thickness CT3 greater than that of the first lens 101 (CT1). The fourth lens 104 is positioned on the sensor side of the optical filter 155 and may have a refractive index less than that of the fourth lens 104 and a center thickness CT4 greater than that of the first lens 101 (CT1). The center distance CG3 between the third lens 103 and the fourth lens 104 may be greater than the thickness of the optical filter 155. The center distance CG3 between the third lens 103 and the fourth lens 104 may be the largest among the center distances between two adjacent lenses within the optical system 100. The optical filter 155 may be positioned between two lenses among the first to fifth lenses 101-105 that have a center thickness greater than that of the other lenses.

[0081] Described as the absolute value of the radius of curvature, the lens surface within the optical system 100 with the smallest radius of curvature relative to the optical axis OA can be the fourth surface S4 of the second lens 102 or the ninth surface S9 of the fifth lens 105, for example, the fourth surface S4. Therefore, the center distance between the first lens 101 and the second lens 102 can be increased, and the center distance between the fourth lens 104 and the fifth lens 105 can be decreased. The lens surface within the optical system 100 with the largest radius of curvature can be the tenth surface S10 of the fifth lens 105, which is a spherical surface. By adjusting the radius of curvature of the lens, diffuse reflection between adjacent lens surfaces can be prevented to reduce lens ghosting, and multipath interference (MPI) caused by lens artifacts can also be prevented. The tenth surface S10 of the fifth lens 105 has a radius of curvature of 200 mm or more, and can be 20 times or more than the radius of curvature of the ninth surface S9.

[0082] In the optical system 100 of this embodiment, the sum of the refractive indices of the lenses can be greater than 5, for example, 8.0 or greater, preferably in the range of 8.0 to 12.0, and the average refractive index can be in the range of 1.70 to 1.80. The sum of the Abbe numbers of each lens can be 180 or less, for example, in the range of 120 to 180, and the average Abbe number can be 47 or less, for example, in the range of 23 to 47. By adjusting the glass material and refractive index of the lenses within the optical system 100, degradation of optical performance due to temperature changes from -45 degrees to 120 degrees can be prevented, and thermal compensation can be optimized. In addition, by adjusting the Abbe number of the lenses, deviations in the incident light spot size can be minimized, that is, the spot pattern size can be minimized.

[0083] In optical system 100, the sum of the center thicknesses of all lenses can be 18 mm or greater, for example, in the range of 18 mm to 30 mm, and the average center thickness can be 6 mm or less, for example, in the range of 4 mm to 6 mm. The sum of the center distances between lenses on the optical axis OA can be 10 mm or greater, for example, in the range of 10 mm to 20 mm, and can be less than the sum of the center thicknesses of the lenses. Furthermore, the average effective diameter of each lens surface in optical system 100 can be 20 mm or less, for example, in the range of 9 mm to 20 mm. By adjusting the thickness of each lens in optical system 100, degradation of optical performance due to temperature variations from -45 degrees to 120 degrees Celsius can be prevented, and thermal compensation can be optimized.

[0084] In a receiving optical system according to an embodiment of the present invention, the field of view can be greater than 100 degrees. For example, it can be in the range of 118 degrees or more to 138 degrees, preferably in the range of 128 degrees ± 10 degrees. The field of view can be a horizontal field of view. The F-number of the optical system or camera module can be 1.2 or less. For example, it can be in the range of 0.7 to 1.2 or in the range of 0.7 to 0.9. Therefore, the optical system 100 can provide a bright optical system. In addition, the relative illuminance (RI) can be 85% or more, for example, 88% or more. The size (RMS) of the light spot received by the receiving optical system for LIDAR can be 15 µm or less, for example, 12 µm or less. That is, the condition: the light spot size < pixel size can be satisfied. The diagonal length of the sensing unit 151 can be greater than 2 mm and less than 20 mm. For example, it can be 6.34 mm ± 0.5 mm, and it can be greater than the sensor height in the vertical direction. The present invention can be provided as an in-vehicle LIDAR device, which can suppress the change in the focal position due to temperature change by stacking glass lenses and correct various aberrations by providing an aspherical lens.

[0085] Since the embodiment is applied to the receiving optical system of a LIDAR device, the first lens 101 can be provided as a glass material. This is because compared with plastic materials, glass materials have the advantages of scratch resistance and insensitivity to external temperature. The glass lens is used as the first lens 101 to be placed inside the vehicle or to more effectively prevent scratches caused by foreign objects, and the object-side surface of the first lens 101 can have a convex shape to prevent the accumulation of external foreign objects. The LIDAR device can detect the distance, direction, speed, temperature, material distribution, and concentration characteristics of an object during vehicle operation. Such a LIDAR device can be used in an advanced driver assistance system (ADAS). The optical system 100 according to this embodiment can further include a reflection member (not shown), which is used to change the path of light. The above-mentioned reflection member can be implemented as a prism positioned on the incident side of the first lens 101 and reflecting the incident light in the direction of the lens. Hereinafter, the optical system according to the embodiment will be described in detail.

[0086] As Figure 1 and Figure 2 shown, the center thicknesses of the first lens 101 to the fifth lens 105 are denoted as CT1 to CT5, the edge thicknesses of the effective regions of each lens are denoted as ET1 to ET5, and the center distances between two adjacent lenses are denoted as CG1 to CG4. The first lens 101 to the fifth lens 105 can satisfy the following conditions.

[0087] Condition 1: CT1 < CT3 Condition 2: CT2 < CT5 < CT4

[0088] Condition 3: (CT4-CT5)<(CT3-CT2) Condition 4: ET1 <ET3<ET2

[0089] Condition 5: ET5 <ET4<ET3<CT5

[0090] At least one or both of the center thicknesses CT3 and CT4 of the third lens 103 and the fourth lens 104 are the maximum thicknesses among the lenses, and the center thickness CT1 of the first lens 101 is the minimum thickness among the lenses. The maximum center thickness can be greater than 1.5 times and less than or equal to 3 times the minimum center thickness, and the difference between the maximum and minimum center thicknesses can be greater than or equal to 2 mm and less than or equal to 4 mm. That is, even if the first lens, made of spherical material, provides a thin center thickness, the optical performance may not degrade, and the thickness of the sensor system can be thin. By adjusting the thickness of these glass lenses, thermal compensation can be provided for temperature changes from low to high temperatures.

[0091] Regarding the center distances CG1-CG4 between adjacent lenses, the center distance CG3 between the third lens 103 and the fourth lens 104 is the largest, and greater than the center distance CG1 between the first lens 101 and the second lens 102. The center distance CG4 between the fourth lens 104 and the fifth lens 105 can be the smallest. Here, the difference between the maximum and minimum center distances can be 2 mm or greater, for example, in the range of 2 mm to 4 mm. Furthermore, by providing a maximum center distance between lenses that is less than the maximum center thickness of each lens, the optical system 100 can control the optical path between spherical and aspherical lenses.

[0092] Regarding the effective diameter, the lens with the largest effective diameter can be the first lens 101. The lens surface with the largest effective diameter is the first surface S1. The lens with the smallest effective diameter can be the second lens 102. The lens surface with the smallest effective diameter can be the fourth surface S4 of the second lens 102 or the tenth surface S10 of the fifth lens 105, and can be 0.6 times or less than the first surface S1. The effective diameter of each of the first to fifth lenses 101-105 can be greater than the diagonal length of the effective area of ​​the sensing unit 151.

[0093] Figure 2 It is used for Figure 1 Examples of lens data for an optical system in an embodiment. For example... Figure 2As shown, the radius of curvature at the optical axis OA, the center thickness CT of the lens, the center distance CG between the lenses, the refractive index at the d-line, the Abbe number, the effective diameter, and the focal lengths of the first lens 101, the second lens 102, the third lens 103, the fourth lens 104, and the fifth lens 105 can be set. Figure 3 As shown, the lens surfaces of the second lens 102 and the fifth lens 105 in this embodiment may include aspherical surfaces with a 14th-order aspherical coefficient. For example, the object-side surface L2S1 and sensor-side surface L2S2 of the second lens 102, and the object-side surface L5S9 and sensor-side surface L5S10 of the fifth lens 105, may be lens surfaces with a 14th-order aspherical coefficient. As described above, aspherical surfaces with a 14th-order aspherical coefficient (non-zero value) can significantly modify the shape of the aspherical surface at the periphery, thereby achieving good correction of optical performance at the periphery of the permissible field of view (FOV).

[0094] The focal lengths F1 and F2 of the first lens 101 and the second lens 102 have negative refractive power, and the focal lengths F3, F4 and F5 of the third lens 103, the fourth lens 104 and the fifth lens 105 can have positive refractive power. The second lens 102 and the third lens 103 arranged adjacent to each other can satisfy the following conditions.

[0095] Condition 1: The refractive index of a lens with negative refractive power < the refractive index of a lens with positive refractive power.

[0096] Here, among the lenses, the second lens 102 has negative refractive power, and the third lens 103 has positive refractive power. According to condition 1, the refractive index of the third lens 103 is greater than that of the second lens 102, thus the light dispersion value can be controlled. Chromatic aberration occurs in the optical system, and the second lens 102 and the fifth lens 105 are used to correct for chromatic aberration.

[0097] In this invention, because the first to fifth lenses 101-105 are provided with glass material, the characteristic differences between lenses caused by temperature changes can be eliminated. That is, as the temperature changes from low to high, the lenses repeatedly contract and expand. Because lenses of the same material have the same number of lens characteristic changes due to temperature changes, it is effective to correct chromatic aberration between lenses of the same material even if the temperature changes. For example, as shown in Table 1, it can be seen that when the temperature of the lens barrel or optical system changes from -45°C (low temperature) to 22°C (room temperature) and 90°C (high temperature), the optical characteristics hardly change. Table 1 compares the changes in optical characteristics such as EFL, BFL, F-number (F#), TTL, and field of view (FOV) in the optical system according to the example at room temperature, low temperature, and high temperature. It can be seen that the rate of change of optical characteristics at low temperature relative to room temperature is 5% or less, for example, 3% or less or 2% or less, and the rate of change of optical characteristics at high temperature relative to room temperature is 5% or less, for example, 3% or less or 2% or less.

[0098] [Table 1]

[0099] In Table 1, 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 surface of the sensing unit 151 (i.e., the image sensor), F# is the F-number of the optical system, TTL is the optical axis distance from the center of the object-side surface of the first lens 101 to the surface of the sensing unit 151 (i.e., the imaging surface of the image sensor), and FOV is the field of view of the optical system. As shown in Table 1, it can be seen that the rate of change of optical characteristics such as effective focal length (EFL), TTL, BFL, F-number, and FOV due to temperature changes from low to high temperatures is 10% or less, i.e., 5% or less, for example, in the range of 0% to 5%. This allows for temperature-compensated design of aspherical lenses even when using at least one or two or more aspherical lenses, thereby preventing a decrease in the reliability of optical characteristics. The optical system of the embodiment disclosed above can effectively control aberration characteristics such as chromatic aberration and distortion aberration, and can provide good optical performance in the center and periphery of the FOV.

[0100] When comparing the absolute values ​​of focal lengths, the focal length of the third lens 103 is the maximum among the lenses, and can be 20mm or greater, for example, in the range of 20mm to 45mm. Additionally, the focal lengths of the first lens 101 and the second lens 102 can be 30mm or less, for example, in the range of 5mm to 30mm. The focal lengths of the fourth lens 104 and the fifth lens 105 can be 30mm or less, for example, in the range of 5mm to 30mm. Therefore, the optical system can have improved MTF characteristics, aberration control characteristics, resolution characteristics, etc., within the field of view set by the optical system, and can provide good optical performance at the periphery of the field of view.

[0101] Furthermore, the optical system 100 according to the embodiment can have good optical performance, and its distortion characteristics can be set according to temperature changes within a temperature range from low temperature (-45 degrees) to high temperature (120 degrees). For example, the optical system 100 can be based on any of the following mapping functions for wide-angle lenses. Specifically, the distance (mm) from the surface center (0 field) of the image sensor, which serves as the sensing unit 151, to the 1 field is set to ImgH, that is, ImgH is half the maximum diagonal length (mm) of the effective area of ​​the image sensor. When the half field of view (HFOV) is 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 can be defined as follows. Iso-mapping can be defined as ImgH = F. θ, and the equal-area (equidistant angle) mapping can be defined as ImgH=2 F sin(θ / 2). Additionally, positive... Figures 17 to 19 The reduction in brightness modulation from low to high temperatures is less than 10%, for example, 5% or less, or almost no change. The cross-mapping can be defined as ImgH=F sinθ, and the stereo mapping can be defined as ImgH=2 F tan(θ / 2). Here, Indicator multiplication.

[0102] In order to describe Figure 11 and Figure 13 The transmitting optical system 110 has a diffuser 119 with a microlens array, and the optical path of light passing through the microlens array causes a change in the illumination field (FOI) in an on-axis direction separate from the direction of light propagation. A comparative example shows that, after passing through a one-dimensional microlens array, the change in the FOI occurs in the off-axis direction. Here, when describing the optical path after passing through the diffuser 119, the comparative example has an F... The optical path of θ, while the embodiment has F The optical path of sinθ. That is, if the optical path in spherical coordinates is projected onto a plane to induce imaging on a SPAD, then the condition y=F is satisfied. sinθ.

[0103] like Figure 4 As shown, compared to the design standard (comparative example), the optical system 100 can possess specific distortion characteristics as the field of view (FOV) increases from 0 degrees to the maximum high field of view (HFOV). For example, in an embodiment of the optical system 100, it can be observed that when imaged onto the receiver's SPAD, the resolution increases as it moves from 0 degrees toward the maximum HFOV and the maximum image height (ImgH). This system can possess distortion characteristics that satisfy a specific mapping, different from other examples such as stereographic, equidistance, rectilinear, or equisolid projections. Specifically, this embodiment satisfies the distortion characteristics compared to the aforementioned comparative example 1.

[0104] Furthermore, as the field of view (FOV) increases from 0 degrees to the maximum high field of view (HFOV), optical system 100 exhibits specific distortion characteristics compared to other examples, thereby providing an optical system that satisfies the orthographic projection type. Here, the ratio for distortion characteristics refers to the value of ImgH at a specific HFOV location, and can be understood as being calculated using the formula: ((Other Examples - Embodiments) / Embodiment 100). Therefore, the optical system according to the embodiment can prevent changes in optical properties caused by temperature variations in the temperature range from low temperature (-45 degrees) to high temperature (120 degrees) based on the equal area mapping method, and can have improved optical performance in various temperature ranges.

[0105] Figure 5 It is shown in Figure 1 The plots show the modulation transfer function (MTF) curves of diffraction in the optical system at low temperature, room temperature, and high temperature, and represent the modulation of brightness according to the spatial frequency. Figure 5 As shown, in embodiments of the invention, the deviation of the MTF from room temperature to low or high temperature can be less than 10%, i.e., 7% or less. Here, each MTF curve is measured in increments of 0.302 mm, from 0.000 mm to 3.024 mm.

[0106] Figures 6 to 8 It is shown in Figure 1 The graphs show the aberration characteristics of the optical system at low temperature, room temperature, and high temperature. Figures 6 to 8The aberration graphs show the longitudinal spherical aberration, astigmatism, and distortion measured from left to right. The X-axis represents focal length (mm) and distortion (%), and the Y-axis represents image height. Furthermore, the graphs for longitudinal spherical aberration are for light in wavelength bands of approximately 930 nm, 940 nm, and 950 nm, while the graphs for astigmatism and distortion are for light in a wavelength band of approximately 940 nm. Figures 6 to 8 In the aberration curve diagram, it can be explained that the closer each curve at low temperature, room temperature, and high temperature is to the Y-axis, the better the aberration correction function. That is, the optical system 100 according to the embodiment has improved resolution and can provide good optical performance in both the center and outer perimeter of the FOV. Here, low temperature is -20 degrees or lower, for example, in the range of -20 to -50 degrees; room temperature is 22 degrees ± 5 degrees or 18 to 27 degrees; and high temperature is 85 degrees or higher, for example, in the range of 85 to 120 degrees. Therefore, in Figures 6 to 8 As can be seen from the graph, the reduction in brightness modulation from low temperature to high temperature is less than 10%, for example, 5% or less, or almost no change.

[0107] The receiving optical system according to an embodiment of the present invention can prevent the degradation of optical performance from low to high temperatures by taking into account the characteristics of the optical system used in a vehicle. For example, after designing the lens at room temperature, the value of dn / dt, which is a coefficient of the refractive index changing with temperature, is assembled by taking into account the focal power combination of each lens, and the defocus can be set to ±6.5 or less for the value of the temperature coefficient (dn / dt) based on the refractive index of the lens, as well as the thickness variables at low, room, and high temperatures. For this purpose, the first lens 101, the third lens 103, and the fourth lens 104 are made of spherical glass material, and the second lens 102 and the fifth lens 105 are made of aspherical glass material. Conventional filters are disposed between the sensing unit and the last lens. In embodiments of the present invention, the optical filter 155 can be positioned close to the aperture stop ST, i.e., between the aperture stop ST and the fourth lens 104. Therefore, the incident angle of light incident on the optical filter 155 can be minimized. That is, the incident angle of the main beam incident on the optical filter 155 can be at most less than 25 degrees.

[0108] This overcomes the material limitation that the range of filter transmittance depends on the incident angle on the optical filter 155. For example, when a conventional optical filter is positioned between the sensor and the final lens, the incident angle of the main beam onto the filter is approximately 45 degrees. However, the optical filter 155 of the present invention is positioned around the aperture stop ST, so the incident angle of the main beam can be less than 25 degrees. Considering the transmittance curves when the main beam is incident at an angle of 0 degrees and when it is incident on the optical filter 155 at 20 degrees and 40 degrees, there is an effect of utilizing the filter region more extensively from the incident angle of the main beam of 0 degrees to angles less than 25 degrees.

[0109] Figure 9 This is a graph showing the transmittance (%) when the incident angle of the main beam incident on the filter of the present invention is 0 degrees, 20 degrees, and 40 degrees. An automated optical inspection (AOI) device can be used to check the incident angle of the main beam at the incident surface of the optical filter 155 to determine that the incident angle of the main beam (main ray) incident on the filter from 0 field to 1.05 field is less than 25 degrees in different directions (±Y direction, ±X direction), for example, from 0 degrees to a maximum of 24.8 degrees. Therefore, the problem of the incident angle of the main beam shifting relative to room temperature at low and high temperatures can be minimized.

[0110] The optical system 100 according to the embodiments disclosed above can satisfy at least one or two of the mathematical expressions described below. Therefore, the optical system 100 according to the embodiments can have improved optical characteristics. For example, if the optical system 100 satisfies at least one mathematical expression, the optical system 100 can effectively control aberration characteristics such as chromatic aberration and distortion aberration, and can have good optical performance in both the center and periphery of the field of view (FOV). Additionally, the optical system 100 can have improved resolution. Furthermore, the meaning of the lens thickness at the optical axis OA and the distance between adjacent lenses at the optical axis OA as described in the mathematical expressions can be found in the embodiments disclosed above.

[0111] [Mathematical Expression 1] 0 <CT1 / CT2<2

[0112] CT1 is the center thickness of the first lens 101, and CT2 is the center thickness of the second lens 102. In mathematical expression 1, the center thickness CT1 of the first lens 101 and the center thickness CT2 of the second lens 102 can be set to prevent a decrease in the stiffness of the first lens 101 and to control factors affecting aberrations. Preferably, mathematical expression 1 can satisfy: 0 < CT1 / CT2 < 1.

[0113] [Mathematical Expression 2] 4 <CA11 / CT1<12

[0114] 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 if this is satisfied, a reduction in the strength and optical properties of the glass lens can be prevented. The amount of incident light can be increased by the effective diameter of the object-side surface S1 of the first lens 101. If this value is below the range of mathematical expression 2, the lens may be damaged or the incident efficiency may decrease; and if this value is above the range, the TTL may increase and the weight of the optical system may become heavier. Preferably, mathematical expression 2 can be satisfied: 6 < CA11 / CT1 < 10.

[0115] [Mathematical Expression 3]: 0 <CT5 / CT4<3

[0116] CT4 is the center thickness of the fourth lens 104, and CT5 is the center thickness of the fifth lens 105. By setting the center thickness CT5 of the fifth lens 105 and the center thickness CT4 of the fourth lens 104 in mathematical expression 3, thermal compensation can be optimized according to temperature changes from low to high temperatures, and degradation of optical performance can be prevented. Preferably, mathematical expression 3 can be satisfied: 0.5 < CT5 / CT4 < 1.2.

[0117] [Mathematical Expression 3-1] 0 <CT5 / CT3<2

[0118] CT3 is the center thickness of the third lens 103. By setting the center thicknesses CT3 and CT5 of the third lens 103 and the fifth lens 105 in mathematical expression 3-1, light refracted from the object-side lens can be guided to the sensing unit 151. Preferably, mathematical expression 3-1 can be satisfied: 0.5 < CT5 / CT3 < 1. Therefore, the fifth lens 105, which is closest to the sensing unit 151, can increase its center thickness CT5 and refract the light refracted by the object-side lens to the entire area of ​​the sensing unit 151, while not significantly increasing the effective diameter.

[0119] [Mathematical Expression 4] 0 <CT5 / (CT1+CT2)<3

[0120] In mathematical expression 4, the center thickness CT5 of the fifth lens 105 can be set to be greater than the sum of the center thicknesses CT1 and CT2 of the first lens 101 and the second lens 102. The fifth lens 105 can refract light refracted from the object-side lens to the entire area of ​​the sensing unit 151. Preferably, mathematical expression 4 can be satisfied: 0.5 < CT5 / (CT1 + CT2) < 1. Therefore, the center thickness CT5 of the fifth lens 105 closest to the sensing unit 151 can be relatively thick, and the effective diameter can be increased without significantly increasing it.

[0121] [Mathematical Expression 5] 1 <CG3 / CT1<3

[0122] CG3 is the center distance between the third lens 103 and the fourth lens 104. In mathematical expression 5, the center distance CG3 between the third lens 103 and the fourth lens 104 can be set to be greater than the center thickness CT1 of the first lens 101. Therefore, the minimum distance between the convex sensor-side surface of the third lens 103 and the convex object-side surface of the fourth lens 104 can be provided to be greater than the thickness of the optical filter 155. Preferably, 1.2 < CG3 / CT1 < 2.2 can be satisfied.

[0123] [Mathematical Expression 6] 1 <CG1 / CG4<5

[0124] CG1 is the center distance between the first lens 101 and the second lens 102, and CG4 is the center distance between the fourth lens 104 and the fifth lens 105. In mathematical expression 6, the center distance CG1 between the first lens 101 and the second lens 102 can be set to be greater than the center distance CG4 between the fourth lens 104 and the fifth lens 105, to set the center distance between adjacent spherical lenses 101 and 104 and aspherical lenses 102 and 105. Preferably, 2 < CG1 / CG4 < 4 can be satisfied.

[0125] [Mathematical Expression 6-1] 0 <CG4 / CG2<1

[0126] In mathematical expression 6-1, the center distance CG2 between the second lens 102 and the third lens 103 is set to be greater than the center distance CG4 between the fourth lens 104 and the fifth lens 105. This sets the center distance between the two object-side lenses 102 and 103 relative to the aperture stop ST to be greater than the center distance between the two sensor-side lenses 104 and 105 relative to the aperture stop ST, allowing control of the incident and outgoing light paths of the aperture stop ST. Preferably, 0.1 < CG4 / CG2 < 0.5.

[0127] [Mathematical Expression 7] 2 <CG3 / OFt<15

[0128] OFt is the thickness of the optical filter 155. In mathematical expression 7, by making the center distance CG3 between the third lens 103 and the fourth lens 104 greater than the thickness of the optical filter 155, it can be ensured that the optical filter 155 can be installed in the space between the third lens 103 and the fourth lens 104. Preferably, 5 < CG3 / OFt < 12 can be satisfied.

[0129] [Mathematical Expression 8] 0 <CG3 / (CT1+CG1+CT2) <1

[0130] In Mathematical Expression 8, the center distance CG3 between the third lens 103 and the fourth lens 104 can be set to be less 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. Therefore, the object side surface of the first lens 101 can be set to the maximum effective diameter, and the second lens 102 can be set to the minimum effective diameter. Preferably, 0.2 < CG3 / (CT1 + CG1 + CT2) < 0.8 can be satisfied.

[0131] [Mathematical Expression 9] 1 < TTL / DF2 < 4

[0132] DF2 is the optical axis distance from the imaging surface of the sensing unit 151 to the optical filter 155. In Mathematical Expression 8, the total optical axis length (TTL) and the optical axis distance between the optical filter 155 and the sensing unit 151 can be set. Therefore, the position of the optical filter 155 can be located on the object side rather than on the last lens. Preferably, 1.5 < TTL / DF2 < 3 can be satisfied.

[0133] [Mathematical Expression 10] 1.70 < Nd1

[0134] Nd1 is the refractive index of the first lens 101 at the d line. In Mathematical Expression 10, the refractive index of the first lens 101 is set to be high to control the factors affecting the reduction of the third-order aberration (Seidel aberration) of the optical system, and the aberration that may occur as the TTL becomes slightly longer can be reduced. Mathematical Expression 10 preferably satisfies: 1.75 < Nd1 < 2.1. If it is designed to be lower than the lower limit of Mathematical Expression 10, the performance of reducing aberration can be obtained, but the refractive power of the first lens is weakened, making it difficult to effectively collect light, which may lead to a reduction in the performance of the optical system. If it is designed to be higher than the upper limit of Mathematical Expression 10, there are disadvantages in obtaining materials. Additionally, if the refractive index of the first lens 101 is designed to be lower than the lower limit of Mathematical Expression 10, the curvature radii of the first lens and the second lens can be increased to increase the refractive power of the first lens and the second lens.

[0135] [Mathematical Expression 10-1] GMn_Aver < GLn_Aver

[0136] GLn_Aver is the average refractive index value at the d-line of the spherical glass lens, and GMn_Aver is the average refractive index value at the d-line of the aspherical glass lens used as a glass mold. Spherical lenses are made of non-injection molded glass material, while aspherical lenses are made of injection molded glass material. A spherical lens with a high refractive index is positioned on the object side of an aspherical lens to increase dispersion.

[0137] [Mathematical Expression 11] 0 <Nd1 / Nd3<1.5

[0138] Nd3 is the refractive index of the third lens 103 at the d-line. In mathematical expression 11, the difference between the refractive index of the first lens 101 and the refractive index of the third lens 103 is reduced, thereby preventing a decrease in dispersion caused by the glass lens. Preferably, Nd1 and Nd3 can be the same in mathematical expression 11.

[0139] [Mathematical Expression 12] 0 <Nd3 / Nd4<1.5

[0140] Nd4 is the refractive index of the fourth lens 104 at the d-line. In mathematical expression 12, the refractive index of the third lens 103 is set to be higher than that of the fourth lens 104 to control the dispersion caused by the spherical lens and the dispersion caused by the aspherical lens. Preferably, mathematical expression 12 can be satisfied: 0.5 < Nd3 / Nd4 < 1.2.

[0141] [Mathematical Expression 13] (Vd4) Nd4)<(Vd2 Nd2)

[0142] Nd2 is the refractive index of the second lens 102 at the d-line, and Vd2 and Vd4 are the Abbe numbers of the second and fourth lenses, respectively. In mathematical expression 13, the product of the refractive index and the Abbe number of the second lens 102 is set to be greater than the product of the refractive index and the Abbe number of the fourth lens 104, thereby controlling the dispersion caused by the spherical lens and the dispersion caused by the aspherical lens.

[0143] [Mathematical Expressions 13-1] (Vd3) Nd3)<(Vd5 Nd5)

[0144] Nd3 and Nd5 are the refractive indices of the third lens 103 and the fifth lens 105 at the d-line, and Vd3 and Vd5 are the Abbe numbers of the third lens 103 and the fifth lens 105. In mathematical expression 13-1, the product of the refractive index and the Abbe number of the fifth lens 105 is set to be greater than the product of the refractive index and the Abbe number of the third lens 103, thereby allowing control over the dispersion caused by the spherical lens and the dispersion caused by the aspherical lens.

[0145] [Mathematical Expression 14] BFL <DF2

[0146] BFL is the optical axis distance from the surface of the sensing unit 151 to the center of the sensor side of the last lens (i.e., the fifth lens 105). By satisfying mathematical expression 14, the optical filter 155 can be placed adjacent to the aperture stop ST or positioned on a lens closer to the object side than the last lens. Furthermore, mathematical expression 14: 3 can be satisfied. <DF2 / BFL<7。

[0147] [Mathematical Expressions 14-1] 1 <SD / DF2<1.2

[0148] SD is the distance from the aperture stop ST to the surface of the sensing unit 151 in the optical axis direction. If mathematical expression 14-1 is satisfied, the optical filter 155 can be placed adjacent to the aperture stop ST or placed on the sensor side of the aperture stop ST.

[0149] [Mathematical Expressions 14-2] BFL <CG3<DF2

[0150] [Mathematical Expression 15] CT5 <DF2<TTL / 2

[0151] In mathematical expression 15, the optical axis distance (DF2) 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 and less than half the TTL value. Therefore, the incident angle of the main beam incident on the optical filter 155 can be reduced to less than 25 degrees, and the problem of incident angle shift at low and high temperatures compared to room temperature can be minimized. Preferably, DF2 satisfies: 18 mm < DF2 < 25 mm.

[0152] [Mathematical Expression 16] DF2 <DF1

[0153] DF1 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 can be positioned between lenses, between the third lens 103 and the fourth lens 104, or adjacent to the aperture stop ST. Therefore, the incident angle of the main beam incident on the optical filter 155 can be reduced to less than 25 degrees, and the problem of incident angle shift at low and high temperatures compared to room temperature can be minimized. Preferably, 18 mm < DF2 < DF1 < 25 mm can be satisfied.

[0154] [Mathematical Expression 17] 0.1 <OFt<CG3

[0155] If mathematical expression 17 is satisfied, then optical filter 155 can be positioned between the third lens and the fourth lens.

[0156] [Mathematical Expression 18] 1 <CA11 / CA21<5

[0157] CA11 represents the effective diameter of the first surface S1 of the first lens 101, and CA21 represents the effective diameter of the third surface S3 of the second lens 102. If mathematical expression 18 is satisfied, the optical system 100 can control the incident light and set factors affecting aberrations, and preferably, it can satisfy 1... <CA11 / CA21<2.5。

[0158] [Mathematical Expressions 18-1] 1 <CA11 / CA12<2

[0159] CA12 represents the effective diameter of the second surface S2 of the first lens 101. If mathematical expression 18-1 is satisfied, the amount of incident light is increased, and the increase in the effective diameter of the second lens can be suppressed. Preferably, 1.2 < CA11 / CA12 < 1.8 can be satisfied.

[0160] [Mathematical Expression 19] 0 <CA22 / CA31<1.5

[0161] CA22 represents the effective diameter of the fourth surface S4 of the second lens 102, and CA31 represents the effective diameter of the fifth surface S5 of the third lens 103. If 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 be satisfied: 0.5 < CA22 / CA31 < 1.

[0162] [Mathematical Expression 20] 0.5 <CA42 / CA51<2

[0163] CA42 represents the effective diameter of the eighth surface S8 of the fourth lens 104, and CA51 represents the effective diameter of the ninth surface S9 of the fifth lens 105. If mathematical expression 20 is satisfied, the optical system 100 can establish an optical path that passes through the fourth lens 104 and the fifth lens 105 to the sensing unit 151. Preferably, mathematical expression 20 can be satisfied: 1 < CA42 / CA51 < 1.5.

[0164] [Mathematical Expression 21] 1 <CA11 / CA52<5

[0165] CA52 represents the effective diameter of the tenth surface S10 of the fifth lens 105. If the optical system 100 satisfies mathematical expression 21, the incident light from the first lens 101 can be increased, and an optical path toward the sensing unit 151 can be established through the fifth lens 105. Mathematical expression 21 preferably satisfies: 1 < CA11 / CA52 < 2.5.

[0166] [Mathematical Expression 22] 0 <CG2 / (CT2+CT3)<1

[0167] CG2 is the center distance between the second and third lenses, and CT2 and CT3 are the center thicknesses of the second and third lenses, respectively. If mathematical expression 22 is satisfied, the radius of curvature of the sensor-side surface of the second lens 102 can be set, and the optical path between the second lens 102 and the third lens 103 can be set. Preferably, 0.2 < CG2 / (CT2 + CT3) < 0.6 can be satisfied.

[0168] [Mathematical Expression 23] 0 <CG4 / (CT4+CT5)<1

[0169] If mathematical expression 23 is satisfied, an optical path can be set based on the center distance between the fourth lens 104 and the fifth lens 105. Preferably, 0 < CG4 / (CT4+CT5) < 0.5 can be satisfied.

[0170] [Mathematical Expression 24] 2 <CG_max / CG4<5

[0171] CG_max represents the maximum center distance among the lenses in the optical system. If mathematical expression 24 is satisfied, the maximum center distance between the lenses is positioned closer to the object than the center distance between the fourth lens 104 and the fifth lens 105, thereby suppressing the increase in the size of the fourth lens 104. Preferably, 3 < CG_max / CG4 < 4 can be satisfied.

[0172] [Mathematical Expression 25] 1 <CT5 / BFL<2

[0173] If mathematical expression 25 is satisfied, the incident light can be transmitted through the fifth lens 105 to the entire area of ​​the sensing unit 151. Preferably, 1 < CT5 / BFL < 1.5 can be satisfied.

[0174] [Mathematical Expression 26] 0 <CG3 / CT5<1

[0175] If mathematical expression 26 is satisfied, the effective diameter of the fifth lens 105 can be adjusted. Preferably, 0.5 < CG3 / CT5 < 1 can be satisfied.

[0176] [Mathematical Expression 27] 0 <CG4 / CT5<1

[0177] If mathematical expression 27 is satisfied, the effective diameter of the fifth lens 105 can be adjusted, and aberration characteristics can be improved in the center and periphery of the sensing unit 151. Preferably, 0 < CG4 / CT5 < 0.5 can be satisfied.

[0178] [Mathematical Expression 28] 20<|L5R2| / CT5<70

[0179] L5R2 is the radius of curvature of the sensor-side surface of the fifth lens. If mathematical expression 28 is satisfied, the refractive power of the fifth lens 105 can be controlled, and optical performance can be improved. Preferably, 30 < |L5R2| / CT5 < 60 can be satisfied.

[0180] [Mathematical Expression 29] 10<|L5R2| / L5R1<40

[0181] L5R1 is the radius of curvature of the object-side surface of the fifth lens. If mathematical expression 29 is satisfied, the refractive power of the fifth lens 105 can be controlled and the optical performance improved. Preferably, 20 < |L5R2| / L5R1 < 30 can be satisfied.

[0182] [Mathematical Expression 30] 1 <L1R1 / L1R2<5

[0183] 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. If mathematical expression 30 is satisfied, the refractive power of the first lens 101 can be controlled and the optical performance improved. Preferably, 2 < L1R1 / L1R2 < 5 can be satisfied.

[0184] [Mathematical Expression 31] 5 <L2R1 / L2R2<20

[0185] 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. If mathematical expression 31 is satisfied, the refractive power of the second lens 102 can be controlled and the optical performance improved, and the effective diameter of the sensor-side lens of the second lens 102 can be adjusted. Preferably, 5 < L2R1 / L2R2 < 15 can be satisfied.

[0186] [Mathematical Expression 32] 1 <CT_Max / CG_Max<2

[0187] In mathematical expression 32, the maximum center thickness (CT_Max) of the lens and the maximum distance between adjacent lenses (CG_Max) can be set. If mathematical expression 32 is satisfied, the optical system can provide good optical performance at the focal length of the set field of view and can reduce TTL. Preferably, 1 < CT_Max / CG_Max < 1.5 can be satisfied.

[0188] [Mathematical Expression 33] 1 < ΣCT / ΣCG < 3

[0189] ∑CT is the sum of the center thicknesses of the lenses, and ∑CG is the sum of the distances between adjacent lenses. If mathematical expression 33 is satisfied, the optical system can provide good optical performance at the focal length of the set field of view and can reduce TTL. Preferably, 1.2 < ∑CT / ∑CG < 2.2 can be satisfied.

[0190] [Mathematical Expression 34] 5<ΣNd<15

[0191] ∑Nd represents the sum of the refractive indices at the id line of each of the multiple lenses. If mathematical expression 34 is satisfied, the TTL can be controlled in the optical system 100 in which aspherical and spherical lenses are mixed, and improved resolution can be achieved. Furthermore, if the number of spherical lenses is greater than the number of aspherical lenses, the TTL and the sum of the refractive indices can be set. Mathematical expression 34 preferably satisfies: 7 < ∑Nd < 9.

[0192] [Mathematical Expression 35] 10 < ΣVd / ΣNd < 50

[0193] ∑Vd represents the sum of the Abbe numbers of each of the multiple lenses. If mathematical expression 35 is satisfied, the optical system 100 can have improved aberration characteristics and resolution. Mathematical expression 35 sets the sum of the Abbe numbers and refractive indices of the lenses to control optical characteristics, and preferably satisfies: 13 < ∑Vd / ∑Nd < 23.

[0194] [Mathematical Expression 36] 50<ΣCT n<159

[0195] ∑CT is the sum of the central thicknesses of multiple lenses, and n is the number of lenses in the optical system. If the mathematical expression 36 is satisfied, the TTL can be controlled. Preferably, it satisfies: 100 < ∑CT n < 135.

[0196] [Mathematical expression 37] 1 < CA11 / CA_Min < 4

[0197] CA_Min represents the minimum effective diameter of either the object-side surface or the sensor-side surface of the lens. If the mathematical expression 37 is satisfied, the optical system can provide a thinner module while controlling the incident light and maintaining optical performance. Preferably, the mathematical expression 38 is satisfied: 1 < CA11 / CA_Min < 3. Here, CA11 can be the maximum effective diameter, and the tenth surface S10 of the fifth lens 105 can have the minimum effective diameter.

[0198] [Mathematical expression 38] CA3 < D_OF / CA4 < 4

[0199] CA3 is the average of the effective diameters of the object-side surface and the sensor-side surface of the third lens, D_OF is the effective diameter of the optical filter, and CA4 is the average of the effective diameters of the object-side surface and the sensor-side surface of the fourth lens. If the mathematical expression 38 is satisfied, the incident light can be transmitted through the third lens, the optical filter, and the fourth lens.

[0200] [Mathematical expression 39] 0.5 < CA_Max / DF2 < 1.5

[0201] If the mathematical expression 39 is satisfied, the position of the optical filter 155 can be set based on the maximum effective diameter. Preferably, 0.6 < CA_max / DF2 < 1.3 can be satisfied.

[0202] [Mathematical expression 40] 0.3 < CA_Min / DF2 < 1

[0203] The mathematical expression 40 sets the minimum effective diameter of the lens surface and the position of the optical filter, thereby reducing the TTL. Preferably, 0.3 < CA_Min / DF2 < 0.8 can be satisfied.

[0204] [Mathematical expression 41] 1 < CA_max / (2 ImgH) < 5

[0205] The maximum effective diameter CA_Max and the diagonal length of the sensing unit (2 The mathematical expression 41 is set using ImgH. If this is satisfied, the optical system can maintain good optical performance and can be configured with a thin and compact sensor device. Preferably, the mathematical expression 41 can be satisfied as: 2 < CA_max / (2 ImgH) < 4.3.

[0206] [Mathematical Expression 42] 1 <TD / CA_Max<4

[0207] TD is the optical axis distance from the center of the object-side surface of the first lens to the center of the sensor-side surface of the last lens. If mathematical expression 42 is satisfied, the total optical axis distance and maximum effective diameter of the lenses can be set, allowing for sizing to achieve good optical performance. Mathematical expression 42 preferably satisfies: 1.5 < TD / CA_Max < 2.2.

[0208] [Mathematical Expression 42-1] SD <TD

[0209] SD is the optical axis distance from the position of the aperture to the surface of the sensing unit. Preferably, the condition 2 < TD / SD < 2.5 can be satisfied.

[0210] [Mathematical Expression 43] 0 <F / L5R2<0.5

[0211] F is the effective focal length of the optical system, and L5S2 is the radius of curvature of the sensor-side surface of the fifth lens. Setting the effective focal length and radius of curvature of the sensor-side surface of the final aspherical lens, if mathematical expression 43 is satisfied, allows for control over reductions in the optical system, such as its impact on TTL. Mathematical expression 43 preferably satisfies: 0 < F / L5R2 < 0.2.

[0212] [Mathematical Expression 44] 0 <F / L1R1<0.5

[0213] In mathematical expression 44, the effective focal length of the optical system and the radius of curvature of the object-side surface of the first lens are set to control the influence on the incident light and TTL. Mathematical expression 44 preferably satisfies: 0 < F / L1R1 < 0.25.

[0214] [Mathematical Expression 45] 0 <EPD / |L5R2|<0.5

[0215] EPD refers to the entrance pupil diameter of the optical system 100. If the optical system 100 according to this embodiment satisfies mathematical expression 45, then the optical system 100 is capable of controlling the incident light. Preferably, the condition 0 < EPD / |L5R2| < 0.2 can be satisfied.

[0216] [Mathematical Expression 46] 0 <EPD / L1R1<0.5

[0217] In mathematical expression 46, the entrance pupil diameter of the optical system 100 and the radius of curvature of the object-side surface of the first lens can be set, and if this is satisfied, the optical system 100 can control the incident light. Preferably, the condition 0 < EPD / L1R1 < 0.2 can be satisfied.

[0218] [Mathematical Expression 47] 0 < |F1 / F2| < 5

[0219] F1 is the focal length of the first lens, and F2 is the focal length of the second lens. If mathematical expression 47 is satisfied, the refractive power of the first and second lenses can be controlled to improve resolution and may affect TTL and EFL. Preferably, the condition 1 < |F1 / F2| < 2 can be satisfied, or the condition |F2| < |F1| can be satisfied.

[0220] [Mathematical Expression 48] 0 < |F1| / F < 10

[0221] 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 to improve resolution. Preferably, 0 < |F1| / F < 5 can be satisfied.

[0222] [Mathematical Expression 49] 0 < |F1 / F5| < 10

[0223] In mathematical expression 49, the focal lengths of the first and fifth lenses can be set, and the refractive power of the first and fifth lenses can be controlled to improve resolution. Preferably, 1 < |F1 / F5| < 2 can be satisfied.

[0224] [Mathematical Expressions 49-1] |F1| <F4

[0225] [Mathematical Expressions 49-2] F4 <F3

[0226] [Mathematical Expressions 49-3] F5 <F4

[0227] In mathematical expressions 49-1 to 49-3, F1, F2, F3, F4, and F5 are the focal lengths of the first to fifth lenses, and light can be guided to the effective area of ​​the aspherical lens by adjusting the focal lengths from the spherical lens to the final aspherical lens. The balance of the focal lengths of each lens in the system can suppress differences in focal position caused by temperature variations. Therefore, the degradation of the optical properties of the imaging lens due to temperature changes can be suppressed.

[0228] Here, the aperture stop ST is disposed on the sensor-side surface of the third lens 103. The third lens 103 is positioned closer to the sensor than the aperture stop ST and its nearest neighbor has a focal length greater than zero. In embodiments of the invention, the focal length F3 of the third lens 103 must be designed to be greater than zero (F3 > 0). In this case, because the third lens 103 focuses light, it prevents an increase in the effective diameter of the fourth and fifth lenses, which are positioned closer to the sensor than the third lens 103, and also prevents an increase in TTL, thereby achieving miniaturization of the optical system. Therefore, a wide-angle optical system can be provided with a field of view (FOV) exceeding 100 degrees, for example, in the range of 110 to 130 degrees.

[0229] [Mathematical Expression 50] 0 < | F1 / F4 | < 2

[0230] F1 is the refractive power of the first lens, and F4 is the refractive power of the fourth lens. That is, the refractive powers of the first and fourth lenses are opposite to each other, thus improving aberrations and allowing for effective light guidance using aspherical lenses. When the condition is met: F1 When F4 < 0, the improvement in chromatic aberration is not significant in either lens.

[0231] [Mathematical Expression 51] 20mm <TTL<60mm

[0232] TTL (Total Track Length) refers to the distance (mm) along the optical axis OA from the center of the first surface S1 of the first lens 101 to the imaging surface of the sensing unit 151. By setting TTL in mathematical expression 51, an optical system for vehicles can be provided. Mathematical expression 51 preferably satisfies: 30mm < TTL < 55mm.

[0233] [Mathematical Expression 52] 2mm <ImgH<20mm

[0234] Mathematical expression 52 can set the diagonal size of sensing unit 151 and can provide an optical system compatible with the size of vehicle-mounted sensors. Mathematical expression 52 can preferably satisfy: 2mm < 1mgH < 5mm.

[0235] [Mathematical Expression 53] 3mm <BFL<7mm

[0236] By setting the back focal length (BFL) in mathematical expression 53, mounting space for the cover glass 153 can be ensured, and the assemblability and bonding reliability of the assembly can be improved by adjusting the distance between the sensing unit 151 and the final lens. Mathematical expression 53 preferably satisfies the following condition: 3.5 mm < BFL < 5.5 mm. If BFL is smaller than the range of mathematical expression 53, some light heading towards the sensing unit may not be transmitted to it, potentially leading to a reduction in resolution. If BFL exceeds the range of mathematical expression 53, stray light may be introduced, and the aberration characteristics of the optical system may degrade.

[0237] [Mathematical Expression 54] 1mm <F<10mm

[0238] Mathematical expression 54 allows setting the total focal length (F) to suit automotive optical systems. It satisfies mathematical expression 54: 1mm < F < 5.5mm.

[0239] [Mathematical Expression 55] 100 degrees < FOV

[0240] In mathematical expression 55, FOV refers to the field of view (degrees) of optical system 100, and is a motor vehicle optical system capable of providing an FOV exceeding 100 degrees. Preferably, the FOV can satisfy: 110 ≤ FOV ≤ 130.

[0241] In mathematical expression 55, the range of the vehicle optical system can be set by the field of view. The sensor length in the horizontal direction is based on 6.04 mm ± 0.5 mm. Furthermore, if mathematical expression 55 is satisfied, the rate of change of the effective focal length and the rate of change of the field of view when the temperature changes from room temperature to high temperature can be set to 5% or less, for example, 0 to 5%. Moreover, even when two or more aspherical lenses are used in combination with spherical lenses within the optical system 100, temperature compensation and aberration correction can be performed using aspherical lenses made of glass material to prevent degradation of optical properties.

[0242] [Mathematical Expression 56] 1 <TTL / CA_max<7

[0243] Mathematical expression 56 establishes the relationship between the total optical axis length and the maximum effective diameter of the optical system, thereby providing an improved automotive optical system. Mathematical expression 56 preferably satisfies: 1 < TTL / CA_max < 3.

[0244] [Mathematical Expression 57] 10 <TTL / ImgH<30

[0245] Mathematical expression 57 allows setting the total optical axis length (TTL) and the diagonal length (ImgH) from the center of the sensing unit 151 of the optical system. If the optical system 100 according to the embodiment satisfies mathematical expression 57, the optical system 100 can have a TTL for application to the vehicle-mounted sensing unit 151, thereby providing improved image quality. Preferably, mathematical expression 57 can be satisfied: 10 < TTL / ImgH < 20.

[0246] [Mathematical Expression 58] 1 <BFL / ImgH<2

[0247] Mathematical expression 58 allows setting the optical axis distance between the sensing unit 151 and the fifth lens 105, as well as the diagonal length starting from the center of the sensing unit 151. If the optical system 100 according to this embodiment satisfies mathematical expression 58, the optical system 100 can ensure the BFL (Body Flux) for applying the dimensions of the vehicle-mounted sensing unit 151, set the distance between the fifth lens 105 and the sensing unit 151, and have good optical characteristics in the center and periphery of the FOV. Preferably, mathematical expression 58 can be satisfied: 1.2 < BFL / ImgH < 1.8.

[0248] [Mathematical Expression 58-1] ImgH <BFL<DF2

[0249] BFL can be greater than half the diagonal length of the sensing unit 151 (ImgH) and less than the optical axis distance from the optical filter 155 to the surface of the sensing unit 151.

[0250] [Mathematical Expression 59] 4 <TTL / BFL<15

[0251] Mathematical expression 59 can set the total optical axis length (TTL) of the optical system and the optical axis distance (BFL) between the sensing unit 151 and the final lens. If the optical system 100 according to this embodiment satisfies mathematical expression 59, the optical system 100 can ensure BFL. Mathematical expression 59 can preferably satisfy: 8 < TTL / BFL < 12.

[0252] [Mathematical Expression 60] 0 <F / TTL<0.5

[0253] Mathematical expression 60 can set the total focal length (F) and total optical axis length (TTL) of optical system 100. Therefore, an optical system for driver assistance systems can be provided. Mathematical expression 60 preferably satisfies: 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 within the set TTL range, and provides an optical system that can maintain an appropriate focal length and form an image even when the temperature changes from low to high. If it is below the lower limit of mathematical expression 60, it is necessary to increase the refractive power of the lens, making it difficult to correct spherical aberration or distortion aberration; if it exceeds the upper limit of mathematical expression 60, the effective diameter or TTL of the lens becomes longer, which may lead to a problem of an enlarged imaging lens system.

[0254] [Mathematical Expression 61] 0 <F / BFL<1

[0255] Mathematical expression 61 allows setting the total focal length (F) of the optical system 100 and the optical axis distance (BFL) between the sensing unit 151 and the final lens. If the optical system 100 according to the embodiment satisfies mathematical expression 61, the optical system 100 can have a set field of view and an appropriate focal length, and can be provided as an automotive optical system. Furthermore, the optical system 100 can minimize the distance between the final lens and the sensing unit 151, thereby exhibiting good optical characteristics at the periphery of the field of view (FOV). Preferably, mathematical expression 61 can be satisfied: 0.5 < F / BFL < 1.

[0256] [Mathematical Expression 62] 0.5 <F / ImgH<1.5

[0257] Mathematical expression 62 can be used to set the total focal length (F) of the optical system 100 and the diagonal length (ImgH) starting from the center of the sensing unit 151. Such an optical system 100 can have improved aberration characteristics within the size of the vehicle-mounted sensing unit 151. Mathematical expression 62 can preferably satisfy: 1 ​​< F / ImgH < 1.4.

[0258] [Mathematical Expression 63] 0.5 <F / EPD<1.5

[0259] Mathematical expression 63 allows setting the total focal length (F) and entrance pupil diameter of optical system 100. Therefore, the total brightness of the optical system can be controlled. Mathematical expression 63 preferably satisfies: 0.5 < F / EPD < 1.

[0260] [Mathematical Expression 64] 0 <EPD / ImgH / FOV<0.2

[0261] Mathematical expression 64 can set the relationship between the length of the EPD, half the maximum diagonal length of the sensing unit (ImgH), and the FOV. Therefore, the overall size and brightness of the optical system can be controlled. Mathematical expression 64 preferably satisfies: 0 < EPD / ImgH / FOV < 0.1.

[0262] [Mathematical Expression 65] 100 <FOV / F#<200

[0263] Mathematical expression 65 establishes the relationship between the field of view (FOV) and the F-number (F#) of the optical system. Preferably, mathematical expression 65 can satisfy: 120 < FOV / F# < 170. Here, F# is provided as 1.2 or less to provide a bright image.

[0264] [Mathematical Expression 66] 40 < (CT_Max + CG_Max) n<140

[0265] [Mathematical Expression 67] 800 < (FOV) TTL) / n

[0266] Preferably, depending on the FOV and the number of lenses (n), the mathematical expression 67: 1000 < (FOV) can be satisfied. TTL) / n<1200.

[0267] [Mathematical Expression 68] FOV<(TTL) n)

[0268] [Mathematical Expression 69] 5<(TD / CA_Max) n<30

[0269] Preferably, 8 < (TD / CA_Max) can be satisfied. n < 12.

[0270] [Mathematical Expression 70] 0 < (CA52 / CA22) / (CA11 / CA21) < 1.5

[0271] In mathematical expressions 66 to 70, n is the total number of lenses, and depending on the total number of lenses, relationships can be established with the maximum center thickness CT_Max, maximum center distance CG_Max, FOV, TTL, optical axis distance (TD) of the lenses, the effective diameter CA52 of the sensor-side surface of the fifth lens, the effective diameter CA11 of the object-side surface of the first lens, and the effective diameters CA21 and CA22 of the object-side and sensor-side surfaces of the second lens. Therefore, the chromatic aberration, resolution, size, etc., of an optical system with six or fewer lenses can be controlled.

[0272] [Mathematical Expression 71]

[0273] In mathematical expression 71, Z can represent sag, which is the distance from any point on the aspherical surface to the vertex of the aspherical surface along the optical axis. Y can represent the distance from any point on the aspherical surface to the optical axis in the direction perpendicular to the optical axis. c can represent the curvature of the lens, and K can represent the conic constant. Additionally, A, B, C, D, E, and F can represent aspherical constants from the 4th to the 14th order.

[0274] The optical system 100 according to the embodiment can satisfy at least one or two of mathematical expressions 1 to 70. In this case, the optical system 100 can have improved optical characteristics. Specifically, if the optical system 100 satisfies at least one of mathematical expressions 1 to 35 and / or at least one of mathematical expressions 36 to 70, the optical system 100 can have improved resolution and improved aberration and distortion characteristics. In addition, the optical system 100 can ensure the back focal length (BFL) for the application of the vehicle-mounted sensing unit 151, compensate for the degradation of optical characteristics caused by temperature changes, and minimize the distance between the final lens and the sensing unit 151, thereby achieving good optical performance in both the center and periphery of the FOV.

[0275] Table 2 relates to the items in the above mathematical expressions of the optical system 100 of this embodiment, and relates to the TTL, BFL, F, ImgH, effective diameter, sum of center thicknesses of each lens, sum of center distances between adjacent lenses, sum of Abbe numbers, sum of refractive indices, TD as the optical axis distance from the first surface S1 to the tenth surface S10, focal lengths F1, F2, F3, F4 and F5 of each of the first to fifth lenses, field of view (degrees), edge thickness (ET), F number, etc.

[0276] [Table 2]

[0277] Table 3 shows the resulting values ​​of mathematical expressions 1 to 35 for the optical system 100 of this embodiment. Referring to Table 3, it can be seen that the optical system 100 satisfies at least one, two or more, or three or more of mathematical expressions 1 to 35. Specifically, it can be seen that the optical system 100 according to this embodiment satisfies all of mathematical expressions 1 to 35. Therefore, the optical system 100 is able to provide good optical performance and excellent optical characteristics at both the center and periphery of the FOV.

[0278] [Table 3]

[0279] Table 4 shows the resulting values ​​of the mathematical expressions 36 to 70 for the optical system 100 of this embodiment. Referring to Table 4, it can be seen that the optical system 100 satisfies at least one, two or more, or three or more of the mathematical expressions 36 to 70. Specifically, it can be seen that the optical system 100 according to this embodiment satisfies all of the mathematical expressions 1 to 70. Therefore, the optical system 100 is able to provide good optical performance and excellent optical characteristics at both the center and periphery of the FOV.

[0280] [Table 4]

[0281] Figure 10 This is a block diagram of a sensor system with a transmitting / receiving optical system according to an embodiment of the present invention.

[0282] refer to Figure 10 The sensor device includes a control unit 10, a light source driving unit 20, a transmitting optical system 30, a receiving optical system 50 disclosed above, and a signal processing unit 60.

[0283] The control unit 10 controls the transmission and reception of signals, and can link with devices such as autonomous driving modules, artificial intelligence modules, drones, robots, augmented reality devices, virtual reality devices, and 5G and 6G communication service-related devices based on the transmitted / received signals. The light source driving unit 20 supplies power to the light source included in the transmitting optical system 30 to drive it. 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 change the driving current supplied to the light source according to driving environment information. Driving environment information may include terrain information of the driving section, traffic congestion information, weather, etc.

[0284] The wavelength of the laser beam generated from the light source can 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 can be 1550 nm ± 10 nm. The laser source can be implemented as an InGaAs / GaAs-based semiconductor diode laser and can emit a high-power laser beam. The light source can include a single emitter and / or multiple emitters. The transmitting optical system 30 transmits the laser beam generated from the light source to the object 40 through a lens section and a diffuser, and the light reflected from the object 40 is received by the receiving optical system 50. The receiving optical system 50 can consist of multiple light sensors, and the light sensors use photodiodes to convert the received light into electrical signals. That is, the sensing units are arranged in a matrix type and convert the light received from the object scanning in the horizontal and vertical directions into current.

[0285] The signal processing unit 60 converts the output of the receiving optical system 50 into a voltage and amplifies it, then uses an analog-to-digital converter to convert the amplified signal into a digital signal. The signal processing unit 60 uses a time-of-flight (TOF) algorithm or a phase-shift algorithm to analyze the digital data to detect the distance and shape of the object 40. The control unit 10 can receive vehicle speed information and road condition information via a control unit (ECU) or a network. The control unit 10 can also receive driving environment information via a network. Driving environment information may include terrain information of the driving segment, traffic congestion information, weather, etc. The control unit 10 can adjust the gain based on one or more of the vehicle speed, the road conditions of the road the vehicle is traveling on, and the driving environment information, and can provide the autonomous driving device with sensor data including the distance to the object and the shape of the object.

[0286] Figure 11 This is a side cross-sectional view of the transmitting optical system of a LIDAR according to an embodiment. Figure 12 It is shown Figure 11 A diagram of the first lens and diffuser of the optical system. Figure 13 This is an example of the optical path of the lens array of the diffuser by comparing examples and embodiments, and Figure 14 It is shown Figure 11 The table shows the lens characteristics of the optical system.

[0287] refer to Figure 11 The optical system 110 and the sensor system therein can be installed inside or outside the vehicle to monitor the driver or sense external objects or lanes. The material of each lens in the lens can be chosen to be glass or plastic, and because the linear expansion coefficient of each lens is smaller for glass than for plastic, glass lenses can be used to suppress changes in the focusing position due to temperature variations. However, when constructing the optical system using spherical glass lenses, there are limitations in reducing the number of lenses, as well as in reducing size and weight.

[0288] Optical system 110 is a transmitting optical system and may include spherical lenses and aspherical lenses. Here, a spherical lens is a lens in which at least one of the object-side surface and the light source-side surface of the lens is spherical on the optical axis. An aspherical lens is a lens in which at least one of the object-side surface and the light source-side surface of the lens is aspherical on the optical axis. Optical system 110 may include spherical glass lenses and aspherical glass lenses. Furthermore, because aspherical lenses are used, the total length (TTL) of optical system 110 can be reduced, and good correction of various aberrations such as spherical aberration and chromatic aberration is possible due to the aspherical lens. In addition, aspherical lenses can minimize distortion in the periphery.

[0289] The optical system 110 may include n lenses, where the nth lens is the last lens adjacent to the image sensor 151, and the (n-1)th lens is the lens closest to the last lens. n is an integer less than or equal to 5, for example, in the range of 3 to 5. The ratio of spherical lenses to aspherical lenses among the n lenses may be 3:1 or 2:2.

[0290] In optical system 110, the first lens 111 closest to the object can be made of glass. Glass material undergoes slight expansion and contraction due to external temperature changes, and its surface is not easily scratched, thus preventing surface damage. Therefore, the lens adjacent to the object in optical system 110 can be a spherical lens, and the lens adjacent to the light source 116 can be an aspherical lens. That is, the last lens closest to the light source 116 in optical system 110 can be an aspherical lens. In optical system 110, the nth lens can be positioned as an aspherical lens. The last lens can emit light from the light source 116 via various paths. The aspherical lens can be a glass mold made of injection-molded glass material. As another example, at least two lenses closest to the light source 116 can be aspherical lenses.

[0291] The lens within the optical system 110 can be made of glass. Because the rate of change of contraction and expansion due to temperature variations is smaller for glass lenses than for plastic lenses, the glass lens can be positioned within the lens barrel in an area adjacent to the outside.

[0292] Each lens may have an object-side surface and a light-source-side surface. Lenses may include lenses with an object-side spherical surface and a light-source-side spherical surface, as well as lenses with an object-side aspherical surface and a light-source-side aspherical surface. In optical system 110, the number of aspherical lenses may be less than the number of spherical lenses. Because optical system 110 places aspherical lenses adjacent to light source 116, it is able to provide light refracted in various ways. Spherical lenses may be made of glass, and aspherical lenses may be made of a glass molding material. Among the lenses in optical system 110, the lens with the highest refractive index may be a spherical lens, and the lens with the highest Abbe number may also be a spherical lens. Therefore, because the lens with the highest refractive index is placed on the object side, it is easy to change the radius of curvature of the lens after the second lens, and it is possible to increase the center thickness.

[0293] In optical system 110, the lens with the largest effective diameter is located closest to the aspherical lens, is made of glass, and may be a spherical lens. In optical system 110, the lens with the smallest effective diameter may be positioned between the spherical lenses. Here, the effective diameter of the lens is the average of the effective diameter of the object-side surface and the effective diameter of the light source-side surface of each lens. Each of lenses 111-114 may include an effective region and an ineffective region. The effective region can be the area through which light incident on each lens passes. That is, the effective region can be defined as the effective area or effective diameter where incident light is refracted to achieve optical properties. The ineffective region may be placed around the periphery of the effective region. The ineffective region can be the area where effective light does not occur from multiple lenses. That is, the ineffective region can be a region unrelated to optical properties. Additionally, the end of the ineffective region may be an area fixed to a lens barrel (not shown) or similar structure that houses the lens.

[0294] Among the lenses in optical system 110, the lens with the maximum center thickness can be a spherical lens, and the lens with the maximum edge thickness can be an aspherical lens. The lens 113 with the maximum thickness and the lens 113 with the maximum effective diameter can be the same lens. The center thickness of the aspherical lens can be greater than the average center thickness of the spherical lens. Such an aspherical lens can be placed adjacent to the light source 116 to refract laser light across the entire area of ​​the object-side lens.

[0295] In optical system 110, the total top length (TTL) can be greater than 5 times LsH, for example, greater than 5 times and less than 15 times. TTL is the distance along the optical axis OA from the center of the object-side surface of the first lens 111 to the surface of the light source 116. LsH is the distance from the center of the light source 116 to the diagonal end, or half the maximum diagonal length of the light source 116. Additionally, the effective diameter of each lens within optical system 110 can be greater than the diagonal length of the light source 116. Within optical system 110, the effective focal length (EFL) can be greater than 5 mm, and the field of view (FOV) can be less than 70 degrees or 29 ± 10 degrees, making it suitable as a standard transmitting optical system in an onboard sensor system. For example, the transmitting optical system and sensor system according to the embodiment can be applied to sensing devices of ADAS (Advanced Driver Assistance Systems) installed inside or outside a vehicle. FOV can be defined as the divergence angle in the transmitting optical system.

[0296] Because the optical system 110 satisfies the mathematical expression: 5 < TTL / LsH < 15, the center thickness of each lens along the optical axis OA can be increased, and the size of the light source 116 can be reduced. Therefore, an optical system for automotive lenses can be provided. Furthermore, for use in automotive cameras, temperature compensation must be applied within the temperature range used as a temperature reliability evaluation standard for automotive electronic components, i.e., -40°C to 120°C. That is, the lens must be configured such that the focal point of the lens remains within a set range even when the lens expands or contracts due to temperature changes. It can consist of lenses made of glass materials capable of the aforementioned temperature compensation, having an overall effective focal length (EFL) greater than 5 mm, for example, in the range of 8 mm to 20 mm. The optical system 110 can achieve a narrow angle by making the effective focal length longer than that of the receiving optical system.

[0297] In optical system 110, the number of lenses with positive (+) refractive power can be two or more, and the number of lenses with negative (-) refractive power can be two or fewer. Because this optical system 110 is a mixture of spherical and aspherical lenses made of glass, it can prevent a reduction in optical performance. In optical system 110, the effective diameter of the lens closest to the object can be smaller than the effective diameter of the lens closest to the light source 116. Therefore, the brightness of the optical system can be controlled. By controlling the size of the effective diameter of each lens, optical system 110 can control the emitted light to compensate for the reduction in optical characteristics caused by changes in resolution and temperature, and can improve chromatic aberration control characteristics. By adjusting the effective diameter of the lenses, optical system 110 can be made smaller.

[0298] Optical system 110 may include a first lens 111, a second lens 112, a third lens 113, and a fourth lens 114, aligned along the optical axis OA from the object toward the light source. The first to fourth lenses 111, 112, 113, and 114 may be defined as lens portions. 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. Light source 116 may be implemented as an InGaAs / GaAs-based semiconductor diode laser and may emit high-power laser light. Light source 116 may include a single emitter and / or multiple emitters. Light source 116 generates laser light in the form of a line source or a point source.

[0299] Described as the absolute value of the radius of curvature, the lens surface within optical system 110 with the smallest radius of curvature relative to the optical axis OA can be the light source-side surface S8 of the fourth lens 114 among the spherical surfaces. Therefore, the center distance CG2 between the second lens 112 and the third lens 113 can be set to be greater than the center distance CG1 between the first lens 111 and the second lens 112. The lens surface within optical system 110 with the largest radius of curvature can be the light source-side surface of the third lens 113. By adjusting the radius of curvature of each lens, the principal ray angle (CRA) from the optical axis to the end of the effective region (i.e., across the entire field) can be minimized to 0.5 degrees or less, thereby maximizing transmission efficiency. Here, as CRA increases, the asymmetry of the divergence angle relative to the center of the light source 116 of optical system 110 increases, and therefore, may reduce transmission efficiency.

[0300] Optical system 110 may include an aperture stop ST. The aperture stop ST controls the amount of light emitted from optical system 110. The aperture stop ST may be placed around the periphery of the object-side surface of the first lens 111. The aperture stop ST may be spaced 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 stop ST may be 1.2 mm or more. Because the aperture stop ST is spaced from the object-side surface of the first lens 111 by the aforementioned distance, an increase in the effective length of the diffuser 119 can be suppressed.

[0301] like Figure 11 and Figure 12 As shown, diffuser 119 can be positioned between the object and aperture stop ST. Diffuser 119 may include a lens array, such as a microlens array, on at least one of its incident and exit surfaces. The microlens array may be positioned on the exit surface of diffuser 119. Each of the microlenses 119A may have a long length in a first direction (vertical direction) and may be spaced apart from each other in a second direction (horizontal direction). Each lens may have a side cross-section including a cylindrical shape and may have a convex hemispherical shape. Diffuser 119 may have a planar shape that is square.

[0302] The diffuser 119 can refract light emitted through the first lens 111 to produce parallel light. Because the light emitted through the first lens 111 is provided as parallel light, Figure 1 The radius of curvature of the object-side surface of the fifth lens 101 of the receiving optical system 100 can be increased to resemble a flat surface. Therefore, the amount of light incident through the fifth lens 101 can be increased.

[0303] In the optical system 110 with the first to fourth lenses 111-114, the object-side diffuser 119 is arranged in a one-dimensional shape, thus the horizontal field of view (HFOV) of the receiving optical system 100 can be diffused to 120 degrees or greater. That is, by arranging a cylindrical lens array with a long length in the first direction (vertical direction) opposite the diffuser 119, the vertical field of view (VFOV) can be increased while the horizontal field of view (HFOV) remains largely unchanged. Due to this diffuser 119, the aspect ratio of the optical system 110 and the receiving optical system 100 is the ratio of the width to the height of the image sensor, and can be expressed as H:V = 1:1. Compared to the aspect ratio of existing receiving optical systems, which is H:V = 3.43:1, this has the effect of enabling optical matching through the diffuser 119 even if the aspect ratios of the optical system and the receiving optical system are different. Therefore, the size of the transmitting / receiving optical system can be reduced.

[0304] In the transmitting optical system 110 of this embodiment, the sum of the refractive indices of the lenses in the lens section 110 is 6 or greater, for example, in the range of 6 to 10, and the average refractive index can be in the range of 1.70 to 1.80. The sum of the Abbe numbers of each lens in the lens section is 180 or less, for example, in the range of 120 to 180, and the average Abbe number can be 50 or less, for example, in the range of 35 to 50. By adjusting the refractive indices of the lenses within the optical system 110, the reduction in transmission efficiency due to temperature variations from -45 degrees to 120 degrees can be prevented, and thermal compensation can be optimized. In addition, by adjusting the Abbe numbers of the lenses, deviations in transmission efficiency based on wavelength can be minimized.

[0305] In the transmitting optical system, the sum of the center thicknesses of all lenses is 13 mm or more, for example, in the range of 13 mm to 23 mm, and the average center thickness can be 3.9 mm or more, for example, in the range of 3.9 mm to 5.9 mm. The sum of the center distances between lenses on the optical axis OA is 25 mm or less, for example, in the range of 8 mm to 20 mm, and can be less than the sum of the center thicknesses of the lenses. The optical system 110 can optimize thermal compensation and prevent degradation of optical performance due to temperature variations from -45 degrees to 120 degrees by adjusting the lens thickness.

[0306] In the optical system according to an embodiment of the invention, the field of view can be less than 70 degrees, for example, in the range of 20 to 60 degrees. The F-number of the optical system or camera module can be 1.8 or less, for example, in the range of 1.2 to 1.8 or 1.2 to 1.7. Therefore, the optical system 110 is capable of providing a bright optical system. In addition, the relative illumination (RI) can be 90% or greater, for example, 93% or greater. The diagonal length of the light source 116 can be 8.33 mm ± 0.5 mm and can be greater than the height of the image sensor in the vertical direction. The invention can be provided as an automotive LIDAR device capable of suppressing changes in focal position due to temperature variations by stacking glass lenses and correcting various aberrations by providing aspherical lenses.

[0307] Figure 11 This is a transmitting optical system used in a LIDAR device, therefore the first lens 111 can be made of glass. This is because glass has the advantages of being scratch-resistant and insensitive to external temperatures compared to plastic materials. The glass lens is used as the first lens 111 to be placed inside a vehicle or to more effectively prevent scratches caused by foreign objects, and the object-side surface of the first lens 111 can have a convex shape to prevent the accumulation of external foreign objects. The LIDAR device is able to detect the distance, orientation, speed, temperature, material distribution, and concentration characteristics of objects during vehicle operation. Such a LIDAR device can be used in advanced driver assistance systems (ADAS). The optical system 110 according to this embodiment may further include a reflective member (not shown) for changing the path of light. The reflective member can be placed on the object side of the diffuser 119 and can be implemented as a prism. The optical system according to the embodiment will be described in detail below.

[0308] refer to Figure 11 and Figure 14 The optical system 110 may include a first lens 111 to a fourth lens 114 that are sequentially aligned along the optical axis OA. Laser light generated from the light source 116 may be emitted through the fourth lens 114, the third lens 113, the second lens 112 and the first lens 111 and irradiated onto an object through a diffuser 119.

[0309] The aperture stop ST can be positioned closer to the diffuser 119 than the object-side surface of the first lens 111. The aperture stop ST can be spaced apart from the vertex of the first surface S1 of the first lens 111 by a predetermined distance CG0. Because the first lens 111 adjacent to the light source side of the aperture stop ST has positive refractive power (F1 > 0), the first lens 111 can refract the emitted light in the direction of the optical axis and prevent the distance between the first lens 111 and the light source side or the rear lens from increasing.

[0310] The diffuser 119 is positioned on the object side of the aperture stop ST and is capable of refracting light passing through the aperture stop ST as parallel light toward the object. For example... Figure 12 and Figure 13 As shown, the diffuser 119 in this embodiment uses a microlens array to control the path of the light passing through. At this time, a change in the illumination field (FOI) occurs in an axial direction separate from the direction of light propagation. Figure 13 In the comparative examples, it can be seen that the change in FOI occurs off-axis after passing through the microlens array. Here, when describing the optical path after passing through diffuser 119, the comparative examples have F The optical path of θ, while the embodiment has f The light path of sinθ.

[0311] The focal power of the first lens 111 can be positive (+) or negative (-) on the optical axis OA, for example, positive (+). The first lens 111 can include plastic material or glass material, for example, it can be glass material. The first lens 111 made of glass material can reduce the changes in the center position and radius of curvature caused by temperature changes in the surrounding environment, and can protect the exit side surface of the optical system 110.

[0312] On the optical axis OA, the first surface S1 on the object side of the first lens 111 can have a convex shape, and the second surface S2 on the light source side can also have a convex shape. The first surface S1 and the second surface S2 can have a spherical shape. The first lens 111 can have convex shapes on both sides. Alternatively, the first lens 111 can have a meniscus shape convex toward the object side. Alternatively, on the optical axis OA, the first surface S1 can have a concave shape, and the second surface S2 can have a convex shape. Because the first surface S1 is convex, the first lens 111 can refract the emitted light in a direction close to the optical axis OA, reducing the distance between the first lens 111 and the second lens 112, and reducing the effective diameter of the first lens 111. Due to the shape of the lens surface of the first lens 111, 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. The first surface S1 and the second surface S2 of the first lens 111 can be set to have no critical point from the optical axis OA to the end (i.e., edge) of the effective region. When the refractive index of the first lens 111 is Nd1, the condition Nd1 > 1.70 or 2.0 > Nd1 > 1.70 can be satisfied. Because the refractive index Nd1 of the first lens 111 is higher than that of the aspherical lens, the radius of curvature of the first surface S1 of the first lens 111 can be larger than that of the aspherical lens, and the lens can be easily manufactured. If the refractive index Nd1 of the first lens 111 is less than this condition, the lens surface must be formed as a sharp concave or convex shape to increase the refractive power of the first lens 111 and the second lens 112. In this case, lens manufacturing is not easy, the lens defect rate increases, and it may lead to a reduction in production output. Because the first lens 111 is placed on the light source side of the aperture stop ST and the diffuser 119, the center thickness CT1 of the first lens 111 can be provided to be thinner than the center thickness of the third lens 113 and the fourth lens 114. In addition, the effective diameter of the first lens 111 can be smaller than the effective diameter of the third lens 113 and the fourth lens 114. Because the first lens 111 is positioned on the light source side of the aperture stop ST and the diffuser 119, the radius of curvature of the first lens 111 can have a radius of curvature that is greater than the average of the absolute values ​​of the radius of curvature of the second lens 112. The radius of curvature of each lens is the average of the absolute values ​​of the radius of curvature of the object-side surface and the light source-side surface of each lens.

[0313] The second lens 112 can be positioned between the first lens 111 and the third lens 113. The power of the second lens 112 can be positive (+) or negative (-) on the optical axis OA, for example, negative (-). The second lens 112 can comprise plastic or glass material, and can be provided, for example, as a spherical lens made of glass. On the optical axis OA, the object-side surface S3 of the second lens 112 can have a concave shape, and the light source-side fourth surface S4 can have a concave shape. The third surface S3 and the fourth surface S4 can be spherical. The third surface S3 and the fourth surface S4 can be configured without a critical point, extending to the end of the central effective region of each lens surface. Alternatively, the third surface S3 can have a convex shape, and the fourth surface S4 can have a concave shape. Alternatively, the second lens 112 can have convex shapes on both sides.

[0314] If the refractive index of the second lens 112 is Nd2, then the condition Nd2 < 1.7 or 1.4 < Nd2 < 1.7 can be satisfied. The refractive index Nd2 of the second lens 112 can be lower than the refractive index of the aspherical lens. Because the fourth surface S4 on the light source side of the second lens 112 is concave and has a small radius of curvature, less than 20 mm, the center distance between the second lens 112 and the third lens 113 can be separated. In addition, if 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, then the condition L2R2 < L2R1 can be satisfied. If this condition is satisfied, the light emitted through the third surface S3 and the fourth surface S4 can be effectively refracted, thereby preventing the effective diameter of the first lens 111 from increasing and reducing the TTL.

[0315] The power of the third lens 113 can be positive (+) or negative (-) on the optical axis OA; for example, it can be positive (+). The third lens 113 can comprise plastic or glass material; for example, it can be glass. On the optical axis OA, the object-side fifth surface S5 of the third lens 113 can have a convex shape, and the light source-side sixth surface S6 can have a concave shape. The third lens 113 can have convex shapes on both sides of the optical axis OA. At least one or both of the fifth surface S5 and the sixth surface S6 can be spherical. At least one or both of the fifth surface S5 and the sixth surface S6 can be configured to have no critical point from the end of the optical axis OA to the effective region. Alternatively, the third lens 113 can have a meniscus shape convex toward the object. Alternatively, the third lens 113 can have a meniscus shape that is concave on both sides or convex toward the light source.

[0316] If the refractive index of the third lens 113 is Nd3, the condition: Nd3 > 1.7 or 2.0 > Nd3 > 1.70 can be satisfied. The first lens 111, the second lens 112, and the third lens 113 can all be aspherical. The first lens 111 and the third lens 113 can have the same refractive index. If the Abbe number of the third lens 113 is Vd3, the condition: Vd3 < Vd4 can be satisfied. Additionally, the condition: 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.

[0317] The power of the fourth lens 114 can have a positive (+) or negative (−) refractive power on the optical axis OA, for example, positive. The fourth lens 114 can include a plastic or glass material and can be provided as a glass material. The fourth lens 114 can be an injection molded glass mold. On the optical axis OA, the object-side seventh surface S7 of the fourth lens 114 can have a convex shape, and the light-source-side eighth surface S8 can have a concave shape. The fourth lens 114 can have a meniscus shape that bulges toward the object. At least one or both of the seventh surface S7 and the eighth surface S8 can be aspherical. The aspherical coefficients of the seventh surface S7 and the eighth surface S8 can be provided as Figure 15 S7 and S8 of L4 in. At least one of the object-side surface and the light-source-side surface of the fourth lens 114 can have a free-form surface, that is, a non-rotationally symmetric surface. Alternatively, the fourth lens 114 can have a meniscus shape that bulges toward the light source 116 on the optical axis OA.

[0318] The seventh surface S7 and the eighth surface S8 of the fourth lens 114 can be set to have no critical points from the optical axis OA to the end of the effective region. As another example, at least one of the seventh surface S7 and the eighth surface S8 can have a critical point. Here, a critical point is 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 can mean a point where the slope value is 0. Additionally, a critical point can be a point where the slope value of the tangent line passing through the lens surface increases and then decreases or decreases and then increases.

[0319] The effective diameter of the fourth lens 114 can 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. The second lens 112 has a lower refractive index than the first lens 111, the third lens 113, and the fourth lens 114, and can have a higher Abbe number than the first lens 111, the third lens 113, and the fourth lens 114.

[0320] The focal power of the first lens 111, the third lens 113, and the fourth lens 114 may have positive values, and the focal power of the second lens 112 may have a negative value. The fourth lens 114 may be an aspherical lens closest to the light source 116. Aberrations such as spherical aberration and chromatic aberration can be improved by having lens surfaces with an aspherical shape.

[0321] The central thicknesses of the first lens 111 to the fourth lens 114 are denoted as CT1 to CT4, the edge thicknesses at the ends of the effective regions of each lens are denoted as ET1 to ET4, and the center distances between two adjacent lenses are denoted as CG1 to CG3.

[0322] The first lens 111 to the fourth lens 114 may satisfy the following conditions.

[0323] Condition 1: CT2 < CT1 < CT3 Condition 2: CT1 < CT4 ≤ CT3

[0324] Condition 3: (CT3 - CT4) < (CT1 - CT2) Condition 4: ET3 < ET1 < ET_{2}

[0325] Condition 5: ET1 < ET2 < ET4 Condition 6: ET4 < ET2 < CT4

[0326] [[ID=!18]]Condition 7: CG1 < CT1 < CG2

[0327] The central thickness CT3 of the third lens 113 is the maximum among the lenses, and the central thickness CT2 of the second lens 112 is the minimum among the lenses. The maximum central thickness may be at least 2 mm thicker than the minimum central thickness. That is, by adjusting the thicknesses of the spherical lens and the aspherical lens, degradation of optical performance can be prevented, and the size of the sensor system or the height of the light source can be provided in a thin form.

[0328] To describe the center distances between adjacent lenses, the center distance CG2 between the second lens 112 and the third lens 113 is the maximum, and the center distance CG3 between the third lens 113 and the fourth lens 114 is the minimum. Here, the difference between the maximum center distance and the minimum center distance may be 5 mm or more, for example, within the range of 5 mm to 7 mm. Additionally, a transmission optical system may be provided in which the maximum center distance between the lenses is less than the maximum central thickness of each lens, and the center distance between the aspherical lens and the spherical lens is not increased. Furthermore, since the maximum center distance between the lenses is provided to be greater than the minimum central thickness of each lens, the optical path can be controlled.

[0329] Note: In the translation of the formula in line 12, "ET_{2}" is used to maintain the correct superscript format in the original text. If there is no specific requirement in the original text, it can also be written as "ET2".The effective diameters of the first lens 111 and the second lens 112 can be made smaller than the effective diameter of the third lens 113 by means of the shape of the light source side surface of the second lens 112 and the distance between the second lens 112 and the third lens 113. The effective diameter of the third lens 113 can be the largest among the lenses.

[0330] The lens with the largest effective diameter can be the third lens 113. The lens surface with the largest effective diameter can be the sixth surface S6 of the third lens 113. The lens with the smallest effective diameter can be the first lens 111 adjacent to the aperture stop ST. The lens surface with the smallest effective diameter can be any one of the third surface S3 and the fourth surface S4 of the second lens 112 or the eighth surface S8 of the fourth lens 114. The effective diameter of each of the first to fourth lenses 111-114 can be greater than the diagonal length of the light source 116. The fourth lens 114 can have an aspherical surface and can guide the incident light to a spherical lens.

[0331] Figure 14 It is used for Figure 11 Examples of lens data for optical systems. For example... Figure 14 As shown, the radius of curvature at the optical axis OA, the center thickness CT of the lens, the center distance CG between lenses, the refractive index at the d-line, the Abbe number, the effective diameter, and the focal length can be set. When comparing focal lengths in absolute values, the focal length of the fourth lens 114 is the maximum among the lenses and can be 100 mm or greater, while the focal length of the second lens 112 is the minimum among the lenses and can be 20 mm or less. Based on absolute values, the focal length of the fourth lens 114 can be five times or greater than the focal length of the first lens 111. The absolute value of the radius of curvature of the second surface S2 of the first lens 111 can be 100 mm or greater, having the largest radius of curvature among the lens surfaces. Therefore, within the field of view set in the optical system, improved MTF characteristics, aberration control characteristics, etc., can be achieved, resulting in good optical performance.

[0332] like Figure 15 As shown, the lens surface of the fourth lens 114 in this embodiment may include an aspherical surface having a conic constant (K) and a 14th-order aspherical coefficient (A~F). For example, the object-side surface and the light source-side surface of the fourth lens 114 may be lens surfaces with a 14th-order aspherical coefficient. As described above, an aspherical surface with a 14th-order aspherical coefficient (non-zero value) can significantly change the shape of the aspherical surface in the periphery, and thus can effectively correct the optical performance of the periphery of the FOV.

[0333] Figure 16 It is shown in Figure 11The plots show the modulation transfer function (MTF) curves of diffraction in the optical system at low temperature, room temperature, and high temperature, and represent the modulation of brightness according to the spatial frequency. Figure 16 As shown, in embodiments of the invention, the deviation of the MTF relative to room temperature versus low or high temperature can be less than 10%, i.e., 7% or less. Here, each MTF curve is measured in increments of 0.394 mm, from 0.000 mm to 3.940 mm.

[0334] Figures 17 to 19 It is shown Figure 11 The curves show the aberration characteristics of the optical system at low temperature, room temperature, and high temperature. Figures 17 to 19 The aberration curves show the longitudinal spherical aberration, astigmatism curves, and distortion measured from left to right. Figures 17 to 19 In the graph, the X-axis represents focal length (mm) and distortion (%), and the Y-axis represents the height of the light source. Additionally, the graphs for spherical aberration are for light in the wavelength bands of approximately 930 nm, 940 nm, and 950 nm, and the graphs for astigmatism and distortion are for light in the wavelength band of approximately 940 nm. Figures 17 to 19 In the aberration diagram, it can be explained that the closer each curve is to the Y-axis at low temperature, room temperature, and high temperature, the better the aberration correction. Here, low temperature is -20 degrees Celsius or lower, for example, in the range of -20 to -50 degrees Celsius; room temperature is 22 ± 5 degrees Celsius or in the range of 18 to 27 degrees Celsius; and high temperature is 85 degrees Celsius or higher, for example, in the range of 85 to 120 degrees Celsius. Therefore, it can be seen that in Figures 17 to 19 The reduction in brightness modulation from low temperature to high temperature is less than 10%, for example, 5% or less, or almost no change.

[0335] The optical system exhibits chromatic aberration, which is corrected by using spaced-apart aspherical lenses. As the temperature changes from low to high, the lenses repeatedly contract and expand. Because lenses made of the same material exhibit the same amount of change in lens properties due to temperature variations, correcting chromatic aberration between lenses made of the same material is effective even when the temperature changes. For example, as shown in Table 1, it can be seen that there is almost no change in optical properties when the temperature of the lens barrel or receiving optical system changes from -45°C (low temperature) to 22°C (room temperature) and 90°C (high temperature).

[0336] Table 5 compares the changes in optical properties such as EFL, BFL, F-number (F#), TTL, and FOV in the transmitting optical system according to the embodiment at room temperature, low temperature, and high temperature. It can be seen that the optical properties at low temperature change at a rate of 5% or less relative to room temperature, for example, 3% or less or 2% or less, and the optical properties at high temperature change at a rate of 5% or less relative to room temperature, for example, 3% or less or 2% or less.

[0337] [Table 5]

[0338] Therefore, as shown in Table 5, it can be seen that the rate of change of optical properties, such as effective focal length (EFL), TTL, BFL, F-number, and FOV, due to temperature changes from low to high temperatures is 10% or less, i.e., 5% or less, for example, in the range of 0 to 5%. Even when using at least one aspherical lens, this design allows for temperature compensation of the aspherical lens, thereby preventing a decrease in the reliability of optical properties. The transmitting optical system of the embodiments disclosed above can effectively control aberration characteristics such as chromatic aberration and distortion aberration, and can provide good optical performance in both the center and periphery of the field of view. 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 transmitting 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 field of view or divergence angle of the receiving optical system.

[0339] refer to Figure 20 As the viewing angle increases from 0 degrees to the maximum HFOV (half FOV), the optical system 110 can have defined distortion characteristics compared to the design standard (comparative example). For example, in an embodiment of the optical system 110, it can be seen that the light source height further increases as the viewing angle moves from 0 degrees toward the maximum half FOV. Furthermore, it can possess satisfactory distortion characteristics compared to other mapping examples such as spherical planes, equidistant, linear, or isostatic planes. Specifically, this embodiment satisfies the distortion characteristics compared to Comparative Example 1. Here, half field of view is half FOV and can be set at an angle of up to approximately 16 degrees relative to the optical axis at 0 degrees.

[0340] Furthermore, compared to other examples, the receiving optical system 110 can have distortion characteristics set as the field of view increases from 0 degrees to the maximum half FOV, thereby providing an optical system that satisfies the orthographic projection type. Here, the ratio of distortion characteristics refers to a value calculated based on the light source height at a specific half FOV position, expressed by the formula: ((Other Examples - Embodiments) / Embodiment 100). Therefore, the optical system according to the embodiment can prevent the optical properties from changing due to temperature fluctuations in the range of low (-40°C) to high (120°C) temperatures based on the equal area mapping method, and can maintain enhanced optical performance across various temperature ranges.

[0341] The transmitting optical system according to embodiments of the present invention can prevent optical performance degradation from low to high temperatures by taking into account the characteristics of optical systems used in vehicles. For example, lenses can be designed at room temperature, and then the values ​​of dn / dt, which is the coefficient of refractive index as a function of temperature, can be assembled by taking into account the combination of focal power of each lens. Then, based on the refractive index of the lens and the values ​​of the temperature coefficients (dn / dt) for low temperature, room temperature, and high temperature, the defocus for the thickness variable can be set to 2.5 μm or less. For this purpose, the first lens 111, the second lens 112, and the third lens 113 are made of spherical glass material, and the fourth lens 114 is made of aspherical glass material.

[0342] The transmitting optical system 110 according to the embodiments disclosed above can satisfy at least one or two of the mathematical expressions described below. Therefore, the optical system 110 according to the embodiments can have improved optical characteristics. For example, if the optical system 110 satisfies at least one mathematical expression, the optical system 110 can effectively control aberration characteristics such as chromatic aberration and distortion aberration. Additionally, the optical system 110 can have improved resolution. Furthermore, regarding the thickness of the lens along the optical axis OA and the distance between adjacent lenses along the optical axis OA as described in the mathematical expressions, reference can be made to the embodiments disclosed above.

[0343] [Mathematical Expression 1] 1 <CT1 / CT2<3

[0344] CT1 is the center thickness of the first lens 111, and CT2 is the center thickness of the second lens. By setting the center thickness CT1 of the first lens 111 and the center thickness CT2 of the second lens 112 in mathematical expression 1, the reduction in the stiffness of the first lens 111 can be prevented, and factors affecting aberration can be controlled. Preferably, mathematical expression 1 can be satisfied: 1.5 < CT1 / CT2 < 2.2.

[0345] [Mathematical Expression 2] 0.5 <CT4 / CT3<1.5

[0346] CT3 and CT4 are the center thicknesses of the third lens 113 and the fourth lens 114. By setting the center thicknesses of the third lens 113 and the fourth lens 114 in mathematical expression 2, it is possible to prevent the reduction of the rigidity and optical properties of the glass lenses and control the factors affecting aberrations. Preferably, CT4 ≤ CT3 can be satisfied.

[0347] [Mathematical Expression 3] 1 <CT3 / CT2<4

[0348] In mathematical expression 3, the center thicknesses of the second lens 112 and the third lens 113 can be set, allowing for optimized thermal compensation based on temperature changes from low to high temperatures and preventing degradation of optical performance. Preferably, mathematical expression 3 can be satisfied: 2.5 < CT3 / CT2 < 3.5.

[0349] [Mathematical Expression 4] 1 <CG2 / CT2<4

[0350] CG2 is the center distance between the second lens 112 and the third lens 113. By setting the center distance between the second lens 112 and the third lens 113 in mathematical expression 4 to this range, light refracted by the aspherical fourth lens 114 can be guided along the distance between the second lens 112 and the third lens 113. Preferably, mathematical expression 4 can be satisfied: 2 < CG2 / CT2 < 3.

[0351] [Mathematical Expression 5] 0.5 <CT3 / (CT1+CT2)<1.5

[0352] Mathematical expression 5 can set the center thickness between the first lens 111, the second lens 112, and the third lens 113. Preferably, it can satisfy mathematical expression 5: 0.8 < CT3 / (CT1+CT2) < 1.2.

[0353] [Mathematical Expression 6] 2 <CG2 / CG1<5

[0354] CG1 is the center distance between the first lens 111 and the second lens 112. In mathematical expression 6, the center distance CG1 between the first lens 111 and the second lens 112 is set to be less than the center distance CG2 between the second lens 112 and the third lens 113, thereby preventing an increase in the effective diameter of the first lens 111. Additionally, the center distance between the spherical lenses can be set using mathematical expression 6. Preferably, it can satisfy 3 < CG1 / CG2 < 4.6.

[0355] [Mathematical Expression 7] 5 <CG2 / CG3<20

[0356] In mathematical expression 7, the center distance CG2 between the second lens 112 and the third lens 113 is set to be greater than the center distance CG3 between the third lens 113 and the fourth lens 114, so that the center distance between the spherical lens and the aspherical lens can be reduced compared to the center distance between spherical lenses. Preferably, 5 < CG2 / CG3 < 10 can be satisfied.

[0357] [Mathematical Expression 8] 0.5 <CT3 / (CT1+CG1+CT2)<1.5

[0358] In mathematical expression 8, the center thickness CT3 of the third lens 113 can be set to be less 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. Preferably, mathematical expression 8 can be satisfied: 0.6 < CT3 / (CT1 + CG1 + CT2) < 1.

[0359] [Mathematical Expression 9] 0.5 <SD / TTL<1.5

[0360] SD is the optical axis distance from the aperture stop ST to the surface of the light source 116, and TTL is the optical axis distance from the object side of the first lens to the surface of the light source. Preferably, 0.8 < SD / TTL < 1.2 can be satisfied. If the optical system satisfies mathematical expression 9, the aperture stop ST can be positioned at the position farthest from the light source 116, that is, closer to the object than the first lens 111, thereby allowing control over the amount of emitted light.

[0361] [Mathematical Expression 10] 1.70 <Nd1

[0362] Nd1 is the refractive index of the first lens 111 at the d-line. By setting the refractive index of the first lens 111 high in mathematical expression 10, factors affecting the reduction of third-order aberrations (Seidel aberrations) of the optical system can be controlled, and aberrations that may occur as the TTL becomes slightly longer can be reduced. Mathematical expression 10 preferably satisfies: 1.75 < Nd1 < 2.0. If it is designed to be below the lower limit of mathematical expression 10, aberration reduction performance can be obtained, but the refractive power of the first lens is weakened, so light cannot be collected effectively, and the performance of the optical system may deteriorate. If it is designed to be above the upper limit of mathematical expression 10, there is a disadvantage that the material becomes difficult to obtain. In addition, if the refractive index of the first lens 111 is designed to be below the lower limit of mathematical expression 4, the radii of curvature of the first and second lenses can be increased to increase the refractive power of the first and second lenses.

[0363] [Mathematical Expression 11] 0.5 <Nd1 / Nd3<1.5

[0364] Nd1 and Nd3 are the refractive indices of the first lens 111 and the third lens 113 at the d-line. In mathematical expression 11, the difference between the refractive indices of the first lens 111 and the third lens 113 can be reduced to prevent a decrease in dispersion caused by the glass lenses. Preferably, the refractive indices of the first lens, the second lens, and the third lens can be the same.

[0365] [Mathematical Expression 12] 1 <Nd1 / Nd4<1.5

[0366] Nd1 and Nd4 are the refractive indices of the first lens 111 and the fourth lens 114 at the d-line. In mathematical expression 12, the refractive index of the first lens 111 is set to be higher than that of the fourth lens 114 to control the dispersion caused by the spherical lens and the dispersion caused by the aspherical lens. Preferably, mathematical expression 12 can be satisfied: 1 < Nd1 / Nd4 < 1.2.

[0367] [Mathematical Expression 13] (Vd3) Nd3)<(Vd4 Nd4)

[0368] Nd3 and Nd4 are the refractive indices of the third lens 113 and the fourth lens 114 at the d-line, and Vd3 and Vd4 are the Abbe numbers of the first lens and the fourth lens, respectively. In mathematical expression 13, the product of the refractive index and the Abbe number of the first lens 111 is set to be less than the product of the refractive index and the Abbe number of the fourth lens 114, in order to control the dispersion caused by the spherical lens and the dispersion caused by the aspherical lens.

[0369] [Mathematical Expression 14] TD <SD

[0370] SD is the optical axis distance from the aperture stop 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. If the optical system satisfies mathematical expression 14, the aperture stop ST can be located on the object side instead of on the first lens 111.

[0371] [Mathematical Expressions 14-1] TTL <SD

[0372] If mathematical expression 14-1 is satisfied, the position of the aperture stop ST can be set to be on the object side instead of on the first lens 111.

[0373] [Mathematical Expression 15] 1 <CA42<CT4<3

[0374] CA42 is the effective diameter of the light source side surface of the fourth lens 114, and CT4 is the center thickness of the fourth lens. If mathematical expression 15 is satisfied, the effective diameter of the final lens can be set such that it is not large relative to the center thickness. Preferably, 1.2 < CA42 < CT4 < 2 can be satisfied.

[0375] [Mathematical Expression 16] 1 <CA3 / CA2<3

[0376] CA2 and CA3 are the effective diameters of the second and third lenses. CA2 and CA3 represent the average effective diameters of the second and third lenses on the object side and sensor side, respectively. A lens with the maximum effective diameter and a lens with the minimum effective diameter can be set if mathematical expression 16 is satisfied. Preferably, 1.3 < CA3 / CA2 < 2.3 can be satisfied.

[0377] [Mathematical Expression 17] 0.5 <CA1<CA2<1.5

[0378] CA1 is the effective diameter of the first lens. That is, CA1 is the average of the effective diameters of the object-side surface and the light source-side surface of the first lens. In mathematical expression 17, the effective diameters of two exit-side lenses or exit-side spherical lenses can be set. Preferably, 0.8 < CA1 < CA2 < 1.2 can be satisfied.

[0379] [Mathematical Expression 18] 1 <CA3 / CA4<2

[0380] CA3 and CA4 represent the effective diameters of the third lens 113 and the fourth lens 114. In mathematical expression 18, the effective diameters of two light-source-side lenses or adjacent spherical and aspherical lenses can be set. If mathematical expression 18 is satisfied, the emission efficiency of light emitted from the light source 116 can be improved, and preferably, it can satisfy 1.2. <CA3 / CA4<1.6。

[0381] [Mathematical Expression 19] 1 <CA32 / CA21<3

[0382] CA32 represents the effective diameter of the sixth surface S6 of the third lens 113, and CA21 represents the effective diameter of the third surface S3 of the second lens 112. If mathematical expression 19 is satisfied, the optical system 110 can control the light path emitted from the light source 116 and can set the light source side surface of the second lens 112 to a concave shape. Preferably, mathematical expression 19 can be satisfied: 1.5 < CA32 / CA21 < 2.

[0383] [Mathematical Expression 20] 0.5 <CA11 / ST_CA<1.5

[0384] CA11 represents the effective diameter of the first surface S1 of the first lens 111, and ST_CA represents the effective diameter of the aperture stop ST. When equation 20 is satisfied, the optical system 110 can set an optical path emanating from the first lens 111 toward the aperture stop ST. Preferably, the mathematical expression 20 can satisfy the following condition: 1 < CA11 / ST_CA < 1.3.

[0385] [Mathematical Expression 21] 2 <CA11 / CG0<8

[0386] CG0 is the optical axis distance between the first lens 111 and the aperture stop ST or diffuser 119. If 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 preferably satisfies: 4 < CA11 / CG0 < 7.5.

[0387] [Mathematical Expression 22] 0 <CG0 / CT1<1

[0388] When the optical system satisfies Equation 22, the optical axis distance between the first lens (111) and the aperture stop (ST) or diffuser (119) and the center thickness of the first lens (111) can be established, thereby allowing control of distortion aberrations. Preferably, the following condition can be satisfied: 0 < CG0 / CT1 < 0.5.

[0389] [Mathematical Expression 23] 0 <ST_CA / CA_Max<1

[0390] CA_Max represents the maximum effective diameter within the lens surface. If the optical system satisfies mathematical expression 23, the total optical axis length can be controlled. Preferably, 0.3 < ST_CA / CA_Max < 0.8.

[0391] [Mathematical Expression 24] 1 <CG_Max / CG0<4

[0392] CG_Max represents the maximum center distance among the distances between lenses in the optical system. When the optical system satisfies mathematical expression 24, a relationship can be established between the maximum center distance between lenses and the optical axis distance between the first lens 111 and the aperture stop ST or diffuser 119. This allows adjustment of the total optical axis length and suppresses the increase of the effective aperture of the first lens 111. Preferably, equation 24 satisfies the following conditions: 3.4 < CG_Max / CG0 < 4 or 3.4 < CG2 / CG0 < 4.

[0393] [Mathematical Expression 25] 0.5 <CT4 / BFL<1.5

[0394] BFL is the optical axis distance from the center of the light source side surface of the fourth lens 114 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. If mathematical expression 25 is satisfied, the emitted light can be transmitted through the fourth lens 114 to the entire area of ​​the third lens 103. Preferably, 0.8 < CT4 / BFL < 1.3.

[0395] [Mathematical Expression 26] 2 <BFL / CG0<6

[0396] In mathematical expression 26, the distance CG0 between the first lens and the aperture stop and the distance BFL between the fourth lens 114 and the light source can be set. If mathematical expression 26 is satisfied, the distance between the object-side configuration and the light source-side configuration of the lens unit can be adjusted. Preferably, 3 < BFL / CG0 < 5 can be satisfied.

[0397] [Mathematical Expression 27] 2 <ST_CA / CG0<8

[0398] If the optical system satisfies mathematical expression 27, the position of diffuser 119 can be set, and due to diffuser 119, the transmitting and receiving optical systems can be optically matched, even if they provide different aspect ratios. Preferably, 5 < ST_CA / CG0 < 7 can be satisfied.

[0399] [Mathematical Expression 28] 1 <L4R2 / CT4<5

[0400] L4R2 is the radius of curvature of the light source side surface of the fourth lens. If mathematical expression 28 is satisfied, the refractive power of the fourth lens 114 can be controlled and the optical performance can be improved. Preferably, 1 < L4R2 / CT4 < 2 can be satisfied.

[0401] [Mathematical Expression 29] 0.5 <L4R2 / L4R1<1.5

[0402] L4R1 is the radius of curvature of the object-side surface of the fourth lens. If mathematical expression 29 is satisfied, the refractive power of the fourth lens 114 can be controlled and the optical performance can be improved. Preferably, 0.5 < L4R2 / L4R1 < 1 can be satisfied.

[0403] [Mathematical Expression 30] 0 <L1R1 / |L1R2|<1

[0404] 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. If mathematical expression 30 is satisfied, the refractive power of the first lens 111 can be controlled and the optical performance improved. Preferably, 0 < L1R1 / |L1R2| < 0.5 is satisfied. In this case, the distance between the first lens 111 and the aperture stop ST or diffuser 119 can be set.

[0405] [Mathematical Expression 31] L1R2<0

[0406] The light source side surface of the first lens 111 has a shape that is blocked towards the light source side, and can have a radius of curvature of 100 mm or greater. Therefore, the amount of change in the light incident on the first lens 111 can be reduced. This satisfies L1R1 > 0.

[0407] [Mathematical Expression 32] 1<|L2R1 / L2R2|<3

[0408] 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. If mathematical expression 32 is satisfied, the refractive power of the second lens 112 can be controlled and the optical performance can be improved, and the incident efficiency through the light source-side surface of the second lens 112 can be improved. Preferably, 1 < |L2R1 / L2R2| < 2 is satisfied, and L2R1 < 0 and L2R2 > 0 can be satisfied.

[0409] [Mathematical Expression 33] |L3R2| <L3R1

[0410] 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. If mathematical expression 33 is satisfied, the refractive power of the third lens 113 can be controlled and the optical performance improved. Furthermore, the effective diameters of the first and second lenses can be reduced by adjusting the radius of curvature of the third lens 113 and the distance between the second and third lenses. Preferably, L3R1>0 and L3R2<0 are satisfied.

[0411] [Mathematical Expression 34] 0 <CT_Max / CG_Max<2

[0412] In mathematical expression 34, the maximum center thickness CT_Max within the lens and the maximum distance CG_Max between adjacent lenses can be set. If mathematical expression 34 is satisfied, the optical system can provide good optical performance at the focal length of the set field of view and can reduce TTL. Preferably, 1 < CT_Max / CG_Max < 1.5 can be satisfied.

[0413] [Mathematical Expression 35] 1 < ΣCT / ΣCG < 4

[0414] ∑CT is the sum of the center thicknesses of the lenses, and ∑CG is the sum of the distances between adjacent lenses. If the mathematical expression 35 is satisfied, the optical system can provide good optical performance at the focal length of the set field of view and can reduce TTL. Preferably, 2 < ∑CT / ∑CG < 3 can be satisfied.

[0415] [Mathematical Expression 36] 5<ΣNd<10

[0416] ∑Nd represents the sum of the refractive indices at the d-line of each of the multiple lenses. If mathematical expression 36 is satisfied, the TTL can be controlled in the optical system 110, which mixes aspherical and spherical lenses. Alternatively, if the number of spherical lenses is greater than the number of aspherical lenses, the TTL and the sum of the refractive indices can be set.

[0417] [Mathematical Expression 37] 10 < ΣVd / ΣNd < 50

[0418] ∑Vd represents the sum of the Abbe numbers of each of the multiple lenses. If mathematical expression 37 is satisfied, the optical system 110 can have improved aberration characteristics and resolution. By setting the sum of the Abbe numbers and refractive indices of the lenses in mathematical expression 37, the optical characteristics can be controlled, and preferably, 15 < ∑Vd / ∑Nd < 27 can be satisfied.

[0419] [Mathematical Expression 38] 50<ΣCT n<100

[0420] ∑CT is the sum of the center thicknesses of multiple lenses, and n is the number of lenses in the optical system. TTL can be controlled if the mathematical expression 38 is satisfied. Preferably, 70 < ∑CT can be satisfied. n < 95. Here, n is 4.

[0421] [Mathematical Expression 39] CT2 <ET2

[0422] ET2 is the edge thickness of the second lens. If mathematical expression 39 is satisfied, then light incident on the second lens can be refracted along the optical axis, thereby suppressing the increase in the effective diameter of the first lens.

[0423] [Mathematical Expression 40] 8mm <CA11<15mm

[0424] CA11 is the effective diameter of the first object-side surface S1 of the first lens. If mathematical expression 40 is satisfied, the optical system can increase the output light. Mathematical expression 38 preferably satisfies 8mm < CA11 < 13mm.

[0425] [Mathematical Expression 41] 1 <Fno<2

[0426] F# is the F-number of the optical system. A bright image can be provided if the mathematical expression 41 is satisfied.

[0427] [Mathematical Expression 42] 2 <CA_Max / (2 LsH)<6

[0428] Mathematical expression 42 can be set with the maximum effective diameter CA_Max and the diagonal length of the light source; if satisfied, the optical system can maintain good optical performance and can be configured with a thin and compact sensor device. Mathematical expression 42 preferably satisfies 2 < CA_Max / (2... LsH) < 3.

[0429] [Mathematical Expression 43] 0 <F / L4R2<3

[0430] F is the effective focal length of the optical system, and L4R2 is the radius of curvature of the light source-side surface of the fourth lens. If mathematical expression 43 is satisfied, the effective focal length and radius of curvature of the light source-side surface of the final aspherical lens are set, thereby controlling the reduction effect on the optical system, for example, TTL. Mathematical expression 43 preferably satisfies: 1 < F / L4R2 < 3.

[0431] [Mathematical Expression 44] 0 <F / L1R1<2

[0432] In mathematical expression 44, the effective focal length of the optical system and the radius of curvature of the object-side surface of the first lens are set to control the influence on the outgoing light and TTL. Mathematical expression 44 preferably satisfies: 0.5 < F / L1R1 < 1.

[0433] [Mathematical Expression 45] 0 <EPD / L4R2<2

[0434] EPD refers to the size of the entrance pupil of the optical system 110. If the optical system 110 according to this embodiment satisfies mathematical expression 45, then the optical system 110 can control the emitted light. Preferably, the condition 0.5 < EPD / L4R2 < 1.5 can be satisfied.

[0435] [Mathematical Expression 46] 0 <EPD / L1R1<1

[0436] 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 if these conditions are met, the optical system 110 can control the emitted light. Preferably, the condition 0.3 < EPD / L1R1 < 0.8 can be satisfied.

[0437] [Mathematical Expression 47] 1<|F1 / F2|<3

[0438] F1 is the focal length of the first lens, and F2 is the focal length of the second lens. If 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 affected. Preferably, 1 < |F1 / F2| < 2. The first lens 111 and the second lens 112 have focal powers with opposite signs, thus allowing for aberration correction.

[0439] [Mathematical Expression 48] 2 <F1 / F<10

[0440] 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.

[0441] [Mathematical Expression 49] 2 <F4 / F1<10

[0442] In mathematical expression 49, the focal lengths of the first and fourth lenses can be set, and the refractive power of the first and fourth lenses can be controlled. Preferably, 3 < F4 / F1 < 9 can be satisfied.

[0443] [Mathematical Expression 50] F2<0

[0444] F2 is the focal length of the second lens and has a negative value. The second lens can improve the chromatic aberration caused by the third and fourth lenses.

[0445] [Mathematical Expression 51] 20 mm <TTL<60 mm

[0446] TTL (Total Track Length) refers to the distance along the optical axis OA from the center of the first surface S1 of the first lens 111 to the imaging surface of the light source 116. By setting the TTL to the range described above in mathematical expression 51, an optical system for vehicles can be provided. Mathematical expression 51 preferably satisfies: 25mm < TTL < 55mm. Furthermore, the TTL of the transmitting optical system can be less than the TTL of the receiving optical system. Furthermore, the number of lenses in the transmitting optical system can be less than the number of lenses in the receiving optical system. Furthermore, the number of aspherical lenses in the transmitting optical system can be less than the number of aspherical lenses in the receiving optical system.

[0447] [Mathematical Expression 52] 2 mm <LsH<10 mm

[0448] LsH is half the diagonal length of the light source. Mathematical expression 52 can set the diagonal length of the light source 116 and can provide an optical system with the size of an onboard sensor. Mathematical expression 52 preferably satisfies: 2mm < LsH < 5mm.

[0449] [Mathematical Expression 53] 1.5 mm <BFL<9 mm

[0450] In mathematical expression 53, the back focal length (BFL) is set to be greater than 1.5 mm and less than 9 mm, thereby improving the assemblability of the components and enhancing the reliability of the joint by adjusting the distance between the light source 116 and the final lens. Mathematical expression 53 preferably satisfies the following condition: 5 mm < BFL < 7 mm. If BFL is less than the range of mathematical expression 53, some light emitted from the light source may not be emitted, potentially leading to a reduction in resolution. If BFL exceeds the range of mathematical expression 53, stray light may be emitted, which could degrade the aberration characteristics of the optical system.

[0451] [Mathematical Expression 54] 5 mm <F<30 mm

[0452] The mathematical expression 54 can set the total focal length (F) to suit the transmitting optical system of the vehicle. The mathematical expression 54 can be satisfied: 10 mm < F < 20 and it can be greater than the total focal length of the receiving optical system.

[0453] [Mathematical expression 55] FOV < 70 degrees

[0454] In the mathematical expression 55, FOV refers to the field of view (degrees) of the optical system 110, and a vehicle-mounted optical system with a FOV less than 70 degrees can be provided. Preferably, FOV: 20 ≤ FOV ≤ 50 can be satisfied. The FOV of the optical system can be provided to be narrower than the FOV of the receiving optical system. That is, even if the FOV of the receiving optical system is widened by the diffuser 119, a decrease in the sensitivity of the sensing unit can be prevented. In the mathematical expression 55, the range of the vehicle-mounted optical system can be set by the FOV. When the mathematical expression 55 is satisfied, the change rate of the effective focal length and the change rate of the FOV when the temperature changes from room temperature to a high temperature can be set to 5% or less, for example, 0 to 5%. Additionally, even if an aspherical lens is mixed with a spherical lens within the optical system 110, degradation of optical characteristics can be prevented through temperature compensation and aberration correction of the aspherical lens made of a glass material.

[0455] [Mathematical expression 56] 1 < TTL / CA_Max < 7

[0456] The mathematical expression 56 can provide an improved motor vehicle optical system by establishing the relationship between the total optical axis length and the maximum effective diameter of the optical system. The mathematical expression 56 can preferably be satisfied: 1 < TTL / CA_Max < 3.

[0457] [Mathematical expression 57] 5 < TTL / LsH < 15

[0458] The mathematical expression 57 can set the total optical axis length (TTL) of the optical system and the length in the diagonal direction starting from the center of the light source 116. If the optical system 110 according to the embodiment satisfies the mathematical expression 57, the optical system 110 can have a TTL for the application of the vehicle light source 116, thereby providing improved image quality. Preferably, the mathematical expression 57: 6 < TTL / LsH < 11 can be satisfied.

[0459] [Mathematical expression 58] 0 < BFL / LsH < 3

[0460] Mathematical expression 58 can set the optical axis distance between the light source 116 and the fourth lens 114, as well as the length in the diagonal direction starting from the optical axis of the light source 116. If the optical system 110 according to this embodiment satisfies mathematical expression 58, the optical system 110 can ensure the BFL (Browser-to-Flight) for the size of the vehicle light source 116, set the distance between the fourth lens 114 and the light source 116, and have good optical characteristics in the field of view (FOV). Mathematical expression 58 can preferably satisfy: 1 ​​< BFL / LsH < 2.

[0461] [Mathematical Expression 59] 1 <TTL / BFL<15

[0462] Mathematical expression 59 can set the total optical length (TTL) of the optical system and the optical distance (BFL) between the light source 116 and the final lens. If the optical system 110 according to the embodiment satisfies mathematical expression 59, then the optical system 110 can ensure the BFL. Mathematical expression 59 can preferably satisfy: 3 < TTL / BFL < 10.

[0463] [Mathematical Expression 60] 1 <TTL / F<10

[0464] Mathematical expression 60 can set the total focal length (F) and total optical axis length (TTL) of optical system 110. Therefore, an optical system for driver assistance systems can be provided. Mathematical expression 60 preferably satisfies: 1 < TTL / F < 5. When optical system 110 according to the embodiment satisfies mathematical expression 60, optical system 110 can have an appropriate focal length within the set TTL range, and provides an optical system that can maintain an appropriate focal length and form an image even when the temperature changes from low to high. If it is below the lower limit of mathematical expression 60, it is necessary to increase the refractive power of the lens, making it difficult to correct spherical aberration or distortion aberration; if it exceeds the upper limit of mathematical expression 60, the effective diameter or TTL of the lens becomes longer, which may lead to a problem of an enlarged imaging lens system.

[0465] [Mathematical Expression 61] 1 <F / BFL<4

[0466] Mathematical expression 61 allows setting the total focal length (F) of optical system 110 and the optical axis distance between light source 116 and the final lens. If optical system 110 according to the embodiment satisfies mathematical expression 61, then optical system 110 can have a set FOV and an appropriate focal length, and can be provided as an automotive optical system. Furthermore, optical system 110 can minimize the distance between the final lens and light source 116, thereby exhibiting good optical characteristics within the FOV. Mathematical expression 61 preferably satisfies: 2 < F / BFL < 3.

[0467] [Mathematical Expression 62] 1 <F / LsH<5

[0468] Mathematical expression 62 can set the total focal length (F) of optical system 110 and the diagonal length of the optical axis from light source 116. Such optical system 110 can have improved aberration characteristics in terms of the size of vehicle light source 116. Mathematical expression 62 preferably satisfies: 3 < F / LsH < 4.5.

[0469] [Mathematical Expression 63] 1 <F / EPD<3

[0470] Mathematical expression 63 allows setting the total focal length (F) and entrance pupil diameter of optical system 110. Therefore, the total brightness of the optical system can be controlled. Mathematical expression 63 preferably satisfies: 1.2 < F / EPD < 2.

[0471] [Mathematical Expression 64] 0 <EPD / LsH / FOV<0.2

[0472] Mathematical expression 64 allows setting the relationship between the entrance pupil diameter (EPD), half the length of the diagonal of the light source, and the field of view. Therefore, the overall size and brightness of the optical system can be controlled. Mathematical expression 64 preferably satisfies: 0 < EPD / LsH / FOV < 0.1.

[0473] [Mathematical Expression 65] 10 <FOV / F#<30

[0474] Mathematical expression 65 establishes the relationship between the field of view (FOV) and the F-number (F#) of the optical system. Preferably, mathematical expression 65 can satisfy: 15 < FOV / F# < 25.

[0475] [Mathematical Expression 66] 20 < (CT_Max + CG_Max) n<80

[0476] [Mathematical Expression 67] 200<(FOV) TTL) / n<500

[0477] Preferably, depending on the FOV and the number of lenses (n), mathematical expression 67 can satisfy the condition: 200 < (FOV) TTL) / n < 300. Here, n is 4.

[0478] [Mathematical Expression 68] FOV <TTL

[0479] [Mathematical Expression 69] 1<(TD / CA_Max) n<20

[0480] Preferably, 1 < (TD / CA_Max) can be satisfied. n < 10.

[0481] The transmitting optical system 110 according to this embodiment can satisfy at least one or two of mathematical expressions 1 to 69. In this case, the optical system 110 can have improved optical characteristics. Specifically, if the optical system 110 satisfies at least one of mathematical expressions 1 to 35 and / or at least one of mathematical expressions 36 to 69, the optical system 110 has improved resolution and can improve aberration and distortion characteristics. In addition, the optical system 110 can ensure that the BFL used for the vehicle light source 116 compensates for the degradation of optical characteristics due to temperature changes and minimizes the distance between the final lens and the light source 116, thereby achieving good optical performance within the FOV.

[0482] Table 6 relates to the items in the above mathematical expressions of the optical system 110 of the embodiment, and relates to TTL (total track length) (mm), BFL (back focal length), effective focal length (F), LsH, effective diameter (CA), the sum of the center thicknesses of each lens, the sum of the center distances between adjacent lenses, the sum of the Abbe numbers, the sum of the refractive indices, TD (mm) as the optical axis distance from the first surface S1 to the eighth surface S8, the focal lengths F1, F2, F3 and F4 of each lens from the first lens to the fourth lens, FOV, edge thickness (ET), F number, etc.

[0483] [Table 6]

[0484] Table 7 shows the resulting values ​​of the mathematical expressions 1 to 35 described above in the transmitting optical system 110 according to the embodiment. Referring to Table 7, it can be seen that the optical system 110 satisfies at least one, two or more, or three or more of the mathematical expressions 1 to 35. Specifically, it can be seen that the optical system 110 according to this embodiment satisfies all of the mathematical expressions 1 to 35. Therefore, the optical system 110 is able to provide good optical performance and excellent optical characteristics within the FOV.

[0485] [Table 7]

[0486] Table 8 shows the resulting values ​​of the mathematical expressions 36 to 69 described above in the optical system 110 according to the embodiment. Referring to Table 8, 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 69. Specifically, it can be seen that the optical system 110 according to this embodiment satisfies all of the mathematical expressions 1 to 69. Therefore, the optical system 110 is able to provide good optical performance and excellent optical characteristics within the field of view (FOV).

[0487] [Table 8]

[0488] The pixel unit matching results of the transmitting and receiving optical systems according to the present invention are as follows: Figure 22 and Figure 23 As shown in the image. Figure 22 The graph shows the pixel unit matching results based on the light source height and divergence angle of the transmitting optical system; it can be seen that as the light source height increases from the center (0.0) to the end (i.e., 3.8 mm), and as the divergence angle increases, the pixel unit matching increases. Figure 23 This is a graph showing the pixel unit matching results based on image height and field of view in the receiving optical system according to an embodiment of the invention; it can be seen that as the sensor height increases from the center (0.0) to the end (i.e., 3.2 mm), and as the field of view increases, the pixel unit matching increases. Therefore, the matching efficiency of the transmitting and receiving optical systems in a linear LIDAR can be provided to be 95% or higher.

[0489] Figure 24 Figure 1 is a diagram illustrating an example of measuring an object in a vehicle equipped with the sensor system of the present invention, and Figure 25 is a diagram illustrating an example of monitoring the surrounding environment in a vehicle equipped with the sensor system of the present invention.

[0490] refer to Figure 24 As shown in Figure 25, the vehicle 202 with the 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 object 210. Additionally, the sensor system includes a LiDAR system, which typically includes a controller that calculates distance information for the object 210 based on the reflected light, and elements capable of scanning or providing a specific pattern of light, which can be a static pattern within a desired range and field of view (FOV). The transmitting and receiving optical systems are used to convert the received signal light into measurements representing a point-by-point 3D map of the surrounding environment within the range and FOV of the LiDAR system.

[0491] The receiving optics and signal processing unit used in LiDAR calculates distance information based on time-of-flight measurements of light pulses emitted from the light source. Additionally, information about the beam profile, based on the specific design of the light source and projection system, is used to illuminate the scene on a target plane associated with a specific distance, and positional information about reflecting surfaces is used to generate a complete x, y, z, or 3D image of the scene. In other words, a point-by-point 3D map of the surrounding environment represents a set of measurement data indicating the positional information of all surfaces within the LiDAR system's field of view that reflect light from the light source to the receiver. In this way, a 3D representation of objects is acquired within the LiDAR system's field of view.

[0492] Furthermore, a schematic diagram illustrates the two-dimensional field of view and ranging requirements of a typical LIDAR system (200) used for ambient sensing in a vehicle (202). For example, adaptive cruise control may require a field of view and ranging (204) with a narrower field of view and ranging (206) compared to the side view of a "surround view" field of view and ranging (206), but with long ranging requirements. Typically, a vehicle's sensor functionality can be achieved through a combination of LIDAR, radar, cameras, and ultrasonic sensors. The combination of these sensor data that generates information about the surrounding environment is often referred to as "sensor fusion." LIDAR can include linear scan types.

[0493] Although the present invention describes LIDAR systems in the context of motor vehicles, where LIDAR is widely used in autonomous, driverless, or driver-assisted vehicles, it should be understood that these embodiments can be applied to any vehicle. Other types of vehicles may include robots, tractors, trucks, airplanes, drones, boats, ships, etc.

[0494] The features, structures, effects, etc., described in the above embodiments are included in at least one embodiment of the present invention, but are not necessarily limited to one embodiment. Furthermore, the features, structures, and effects illustrated in each embodiment can be combined or modified by those skilled in the art with respect to other embodiments. Therefore, content related to these combinations and variations should be interpreted as being included within the scope of the present invention.

[0495] Furthermore, although described based on embodiments, these are merely examples, and the invention is not limited thereto. It will be apparent to those skilled in the art that various modifications and applications, not illustrated above, are possible without departing from the fundamental characteristics of these embodiments. For example, each component specifically shown in the embodiments may be modified and implemented. And the differences associated with these modifications and applications should be interpreted as being included within the scope of the invention as defined in the appended claims.

Claims

1. An optical system, comprising: The first lens to the fifth lens are aligned along the optical axis from the object toward the sensing part; as well as An optical filter, wherein the optical filter is disposed in any one of the regions between the second lens and the fifth lens. The first lens has a meniscus shape that bulges toward the object along the optical axis. The object-side surface of the third lens has a concave shape along the optical axis. Wherein, the radius of curvature of the object-side surface of the first lens on the optical axis is L1R1. Wherein, the radius of curvature of the sensor-side surface of the first lens on the optical axis is L1R2, and The following mathematical expression satisfies: 1 < L1R1 / L1R2 < 5.

2. The optical system according to claim 1, wherein, The second lens has a convex shape on the object-side surface along the optical axis.

3. The optical system according to claim 1, in, The fourth lens has a convex shape on the sensor side surface on the optical axis.

4. The optical system according to claim 1, in, The fifth lens has a convex shape on the sensor side surface on the optical axis.

5. The optical system according to any one of claims 1 to 4, in, The radius of curvature of the sensor-side surface of the fifth lens is the largest among the absolute values ​​of the radius of curvature of the object-side surfaces and sensor-side surfaces of the first to fifth lenses.

6. The optical system according to any one of claims 1 to 4, in, The optical filter is positioned between two lenses, from the first lens to the fifth lens, that have a thicker center than the other lenses.

7. The optical system according to any one of claims 1 to 4, in, The optical filter is positioned between the third lens and the fourth lens.

8. The optical system according to any one of claims 1 to 4, in, The optical axis distance from the optical filter to the surface of the sensing unit is DF2. Wherein, the optical axis distance from the sensor-side surface of the fifth lens to the surface of the sensing unit is BFL, and The following mathematical expression satisfies: BFL <DF2。 9. The optical system according to claim 7, comprising: An aperture stop is disposed around the object-side surface of the optical filter or the sensor-side surface of the third lens. Wherein, the optical axis distance from the aperture stop to the surface of the sensing unit is SD, and Among them, the following mathematical expressions satisfy: 1 <SD / DF2<1.2。 10. The optical system according to claim 7, in, The distance from the center of the object-side surface of the first lens to the optical axis of the optical filter is DF1, and The following mathematical expression satisfies: DF2 <DF1。 11. The optical system according to any one of claims 1 to 4, in, The first to the fifth lenses are made of glass.

12. The optical system according to any one of claims 1 to 4, in, The object-side surface and sensor-side surface of the second lens and the fifth lens are aspherical.

13. The optical system according to any one of claims 1 to 4, in, The optical filter is a bandpass filter that passes through the range of 890nm to 960nm. Among them, the center distance between the object-side lens and the sensor-side lens relative to the optical filter is the largest among the center distances between the first lens and the fifth lens.

14. The optical system according to any one of claims 1 to 4, in, The first lens and the second lens have negative refractive power, and The third to fifth lenses have positive refractive power.

15. The optical system according to any one of claims 1 to 4, in, The center distance between the third lens and the fourth lens is CG3. Wherein, the thickness of the optical filter is OFt, and The following mathematical expression satisfies: 2 < CG3 / OFt < 15.

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