Receiving optical system, sensor system and lidar device

Abstract

An optical system disclosed in an embodiment of the present application includes a first lens closest to an object, a last lens closest to a sensing unit, a plurality of lenses arranged between the first lens and the last lens and aligned along an optical axis, and an optical filter disposed in any one of regions between the plurality of lenses, wherein a center distance between two lenses adjacent to an object side of the optical filter is greater than a center distance between two lenses adjacent to a sensor side of the optical filter, and when an optical axis distance from an object side surface of the first lens to a surface of the sensor unit is TTL, and 1 / 2 of a diagonal length of the sensing unit is ImgH, a mathematical expression 10 < TTL / ImgH < 30 can be satisfied.

Description

Technical Field

[0001] Embodiments of the present invention relate to a receiving optical system and a sensor system having the receiving optical system. Embodiments of the present invention 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 receiving optical system for LIDAR and a moving object having the system. Background Technology

[0002] ADAS (Advanced Driver Assistance Systems) is a type of advanced driver assistance system that assists the driver while driving. It consists of sensing the situation ahead, assessing the situation based on the sensed information, and controlling the vehicle's behavior based on the assessment. For example, ADAS sensors detect vehicles ahead and identify the lane. Then, once the target lane, target speed, and target ahead are determined, the vehicle's ESC (Electrical Stability Control), EMS (Engine Management System), and MDPS (Motor Drive Power Steering) are controlled. Representative examples of ADAS include automatic parking systems, low-speed city driving assistance systems, and blind spot warning systems.

[0003] Recently, with the increasing interest in autonomous vehicles, the demand for LIDAR (Light Detection and Ranging) sensors, a core component of these vehicles, is growing. Currently, LIDAR is only used in high-specification, expensive vehicles, but due to reduced manufacturing costs, its application in ordinary vehicles is expected to expand as well. Ultra-small and ultra-lightweight LIDAR technology can be used not only as sensors for unmanned mobile devices, but also in satellites and aerospace for observing the Earth's terrain and environment, unmanned vehicles, transportation equipment, cranes, and robots used in factories and shipyards. Furthermore, it is expected to manifest as complex or collaborative operations between mobile devices through integrated approaches in land, aerospace, and marine industries. Therefore, there is an urgent need to develop optical systems for ultra-small and ultra-lightweight LIDAR to achieve this goal. Summary of the Invention

[0004] Technical issues

[0005] The embodiments provide a receiving optical system with improved optical characteristics and a sensor system having the receiving optical system. The embodiments also provide a wide-angle receiving optical system and a sensor system having the wide-angle receiving optical system. Furthermore, the embodiments provide a receiving optical system, a sensor system, and a LIDAR device with improved thermal compensation characteristics.

[0006] Technical solution

[0007] An optical system according to an embodiment of the present invention includes: a first lens adjacent to an object; a last lens adjacent to a sensing unit; a plurality of lenses disposed between the first lens and the last lens and aligned on the optical axis; and an optical filter disposed in one of the regions between the plurality of lenses, wherein the center distance between two lenses adjacent to the object side of the optical filter is greater than the center distance between two lenses adjacent to the sensor side of the optical filter, the optical axis distance from the object side surface of the first lens to the surface of the sensing unit is TTL, and half the diagonal length of the sensing unit is ImH, and the following equation can be satisfied: 10 <TTL / ImgH<30。

[0008] According to an embodiment of the present invention, the optical axis distance from the sensor-side surface of the optical filter to the surface of the sensing part is D1, and the optical axis distance from the sensor-side surface of the last lens to the surface of the sensing part is BFL, and the following equation can be satisfied: 2 <D1 / BFL<6。

[0009] According to an embodiment of the present invention, the optical axis distance from the sensor-side surface of the optical filter to the surface of the sensing unit is D1, and the optical axis distance from the object-side surface of the optical filter to the object-side surface of the first lens is D2, and the following equation can be satisfied: D1 < D2. According to an embodiment of the present invention, the second lens and the third lens are sequentially arranged on the optical filter starting from the first lens, and the center distance between the second lens and the third lens can be greater than the center distance between the first lens and the second lens. According to an embodiment of the present invention, the fourth lens is included between the optical filter and the last lens, and the center distance between the third lens and the fourth lens can be less than the center distance between the second lens and the third lens. According to an embodiment of the present invention, at least two of the lenses in the optical system are aspherical lenses on the optical axis, and the lenses in the optical system can be made of glass. According to an embodiment of the present invention, for some wavelengths in the range of 800 nm to 1000 nm, the optical filter has a transmittance of 90% or greater, and the optical filter can be configured to be closer to the lens located on the object side of the optical filter than the lens located on the sensor side of the optical filter. According to an embodiment of the present invention, the object-side lens and the sensor-side lens arranged on both sides of the optical filter may have a spherical shape on the optical axis. According to an embodiment of the present invention, the lens between the object-side lens adjacent to the optical filter and the first lens may be an aspherical lens made of glass.

[0010] According to an embodiment of the invention, the final lens may be an aspherical lens made of glass. According to an embodiment of the invention, the first lens may have negative refractive power and a meniscus shape convex toward the object, and the final lens may have positive refractive power and a convex shape on both sides. According to an embodiment of the invention, the F-number may be 1 or less.

[0011] The receiving optical system according to an embodiment of the present invention includes: a first lens to a fifth lens aligned on the optical axis from an object toward a sensing unit; and an optical filter spaced apart from the sensing unit and disposed between a third lens and a fourth lens, wherein the first lens has negative refractive power, at least two of the third to fifth lenses have positive refractive power, at least one lens between the first lens and the optical filter has an aspherical shape on the object-side surface and the sensor-side surface, and the fifth lens has an aspherical shape on the optical axis, and the optical axis distance between the second lens and the third lens can be the largest among the optical axis distances between adjacent lenses among the first to fifth lenses.

[0012] According to an embodiment of the present invention, the optical filter includes a bandpass filter, and the optical axis distance from the optical filter to the surface of the sensing unit is D1, and the center thickness of the fifth lens is CT5, and the following formula can be satisfied: (CT5) 3) <D1 < (CT5) 5) According to an embodiment of the present invention, an aperture stop may be included, which is disposed on the periphery between the optical filter and the sensor-side surface of the third lens. According to an embodiment of the present invention, the center distance between the third lens and the fourth lens may be CG3, the center thickness of the fifth lens may be CT5, and the following formula may be satisfied: 1 < CG3 / CT5 < 5. According to an embodiment of the present invention, the first lens may include a convex object-side surface and a recessed sensor-side surface on the optical axis, and the second lens may include a recessed object-side surface and a recessed sensor-side surface on the optical axis.

[0013] According to an embodiment of the present invention, the first to fifth lenses may be made of glass, and the first, third, and fourth lenses may be lenses whose object-side and sensor-side surfaces are spherical. A receiving optical system according to an embodiment of the present invention includes: first to fifth lenses aligned along the optical axis from the object toward the sensing unit; and a bandpass filter disposed between the spherical lenses among the first to fifth lenses, wherein the object-side and sensor-side surfaces of the first, third, and fourth lenses have spherical shapes along the optical axis, the object-side and sensor-side surfaces of the second and fifth lenses have aspherical shapes along the optical axis, the optical axis distance from the sensor-side surface of the fifth lens to the surface of the sensing unit is BFL, half the diagonal length of the sensing unit is ImgH, the optical axis distance from the bandpass filter to the surface of the sensing unit is D1, and the following formula can be satisfied: ImgH <BFL<D1。

[0014] According to an embodiment of the present invention, the first to fifth lenses are made of glass, the bandpass filter is closer to the third lens than the fourth lens, and the optical axis distance from the surface of the first lens to the surface of the sensing part is TTL, and the following formula can be satisfied: 10 < TTL / ImgH < 30.

[0015] Beneficial effects

[0016] According to the embodiments, improved optical characteristics are achieved. Specifically, in the receiving optical system according to the embodiments, the bandpass filter is positioned near the aperture stop, such that the incident angle of light incident on the filter can be minimized. Therefore, the transmittance range of the bandpass filter can be widely utilized depending on the incident angle of the light from the bandpass filter. The receiving optical system of the LIDAR of the present invention can maximize the effect of receiving light emitted from the transmitting optical system.

[0017] The receiving optical system of the LIDAR of the present invention exhibits excellent optical characteristics over a temperature range from low to high temperatures. Specifically, the multiple lenses included in the receiving optical system can have predetermined materials, refractive forces, and refractive indices. Therefore, when the refractive index of each lens changes with temperature and the focal length of each lens changes accordingly, the aspherical and spherical lenses made of glass can compensate for each other. That is, the receiving optical system can effectively distribute the refractive force over a temperature range from low to high temperatures and can prevent or minimize changes in optical characteristics over this temperature range. Therefore, the optical system and sensor system according to the embodiments can maintain improved optical characteristics over various temperature ranges.

[0018] The receiving optical system of the LIDAR of the present invention can have lenses with a set thickness, refractive power, and spacing with adjacent lenses. Therefore, the optical system and sensor system according to the embodiment can have improved MTF characteristics, aberration control characteristics, resolution characteristics, etc., within a set field of view, and can have good optical performance in the periphery of the field of view. The receiving optical system and sensor system according to the embodiment can satisfy the set field of view and achieve excellent optical characteristics by using a combination of spherical and aspherical lenses made of glass. Therefore, the optical system can provide a vehicle sensor system with improved optical performance. Therefore, the optical system and sensor system can be provided for various applications and devices, and can maintain excellent optical characteristics even in harsh temperature environments, such as when exposed to the exterior or interior of a vehicle at high summer temperatures. Attached Figure Description

[0019] Figure 1 This is a side cross-sectional view of the receiving optical system of a LIDAR according to the first embodiment.

[0020] Figure 2 It is shown Figure 1 The table shows the lens characteristics of the receiving optical system.

[0021] Figure 3 It is shown Figure 1 A table of aspherical coefficients of lenses in a receiving optical system.

[0022] Figure 4 It is shown Figure 1 A graph of the diffraction MTF (modulation transfer function) data of the receiving optical system.

[0023] Figure 5 It shows about Figure 1 A graph showing the aberration characteristics of the receiving optical system.

[0024] Figure 6 This is a side cross-sectional view of the receiving optical system of a LIDAR according to the second embodiment.

[0025] Figure 7 It is shown Figure 6 The table shows the lens characteristics of the receiving optical system.

[0026] Figure 8 It is shown Figure 6 A table of aspherical coefficients of lenses in a receiving optical system.

[0027] Figure 9 It is shown Figure 6 A graph of the diffraction MTF data from the receiving optical system.

[0028] Figure 10 It shows about Figure 6 A graph showing the aberration characteristics of the receiving optical system.

[0029] Figure 11 It shows having Figure 1 and Figure 6 A block diagram of the sensor system for the receiving optical system.

[0030] Figure 12 It is shown Figure 11 A side cross-sectional view of the emission optical system of the sensor system.

[0031] Figure 13 This is a diagram illustrating an example of measuring an object in a vehicle equipped with the sensor system of the present invention.

[0032] Figure 14 This is a diagram illustrating an example of ambient monitoring in a vehicle equipped with the sensor system of the present invention. Detailed Implementation

[0033] 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 intended to be interpreted in the sense that would be 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.

[0034] 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 the “connection,” “coupling,” or “joining” of 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.

[0035] In the description of this invention, "object-side surface" can refer to the surface of a lens facing the object relative to the optical axis OA, and "sensor-side surface" can refer to the surface of a lens facing the imaging surface (image sensor) relative to the optical axis. A convex surface of a lens can mean that the lens surface along the optical axis has a convex shape, and a concave surface of a lens can mean that the lens surface along the optical axis has a concave shape. The radius of curvature, center thickness, and distance between lenses described in the table of lens data can refer to values ​​along the optical axis, and the unit is mm. "Vertical direction" can refer to a direction perpendicular to the optical axis, and the end of a lens or lens surface can refer to the end or edge of the effective area of ​​the lens through which incident light passes. Depending on the measurement method, the effective diameter on the lens surface can have a measurement error up to ±0.4 mm. The paraxial region refers to a very narrow region near the optical axis, and is the region where the distance of light rays from the optical axis OA is almost zero. In the following, the concave or convex shape of the lens surface will be described as the optical axis, and may also include the paraxial region.

[0036] Figure 1 and Figure 6 This is a cross-sectional view showing a receiving optical system according to an embodiment of the present invention.

[0037] refer to Figure 1 and Figure 6 The receiving optical system 100 and the sensor system therein can be installed inside or outside the moving body to monitor the driver or sense external objects or lanes. The material of each lens in the receiving optical system 100 can be selected from glass or plastic. The coefficient of linear expansion of glass lenses is less than that of plastic materials. Therefore, at least one of the lenses in the receiving optical system 100 can be made of glass to suppress changes in the focal position due to temperature variations. However, when the optical system is configured with spherical glass lenses, there are limitations on reducing the number of lenses, and also limitations on reducing size and weight.

[0038] The receiving optical system 100 of an embodiment of the present invention 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 receiving optical system 100 may include spherical glass lenses and aspherical glass lenses. In addition, because the optical system 100 includes aspherical lenses, the total track length (TTL) can be reduced, and due to the aspherical lenses, various aberrations such as spherical aberration and chromatic aberration can be well corrected. In addition, aspherical lenses can minimize the distortion portion around the sensing unit 151. The aspherical lenses can be injection molded using glass or plastic.

[0039] The optical system 100 may include n lenses, where the nth lens may be the last lens adjacent to the sensing unit 151, and the (n-1)th lens may be the lens closest to the last lens. n is an integer greater than or equal to 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 may be any one of 3:1, 4:1, 3:2, 2:3, 3:3, 5:2, or 4:2. Preferably, the number of spherical lenses may be equal to or greater than the number of aspherical lenses. Therefore, the price increase of the optical system 100 can be suppressed. The number of spherical lenses may be one or more more than the number of aspherical lenses.

[0040] The receiving optical system 100 may have first lenses 101 and 111 made of glass, closest to the object. 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 lenses 101 and 111 on the object side can be arranged as spherical lenses, and the nth lens can be arranged as an aspherical lens. Because the nth lens in the optical system 100 is set as an aspherical lens, various aberrations can be corrected for the incident light from the sensing unit 151.

[0041] In the optical system 100, at least two lenses closest to the object can be arranged as glass, and compared to lenses made of plastic, the lenses adjacent to the outside have smaller rates of contraction and expansion due to temperature changes, thus preventing degradation of optical properties due to temperature changes within the lens barrel. The optical system 100 can also arrange the last lenses 105 and 115 closest to the sensing unit 151 as glass mold material or aspherical surfaces, and compared to plastic materials, the last lenses 105 and 115 have smaller rates of contraction and expansion due to temperature changes, thus preventing degradation of optical properties due to temperature changes within the lens barrel.

[0042] Each lens in the optical system 100 may have an object-side surface and a sensor-side surface. These lenses may include object-side spherical lenses and sensor-side spherical lenses, as well as object-side aspherical lenses and sensor-side aspherical lenses. The number of aspherical lenses in the optical system 100 may be less than the number of spherical lenses. Object-side aspherical lenses may be disposed between spherical lenses. In addition, at least one spherical lens may be disposed between aspherical lenses. Because the optical system 100 arranges the aspherical lenses adjacent to the sensing unit 151, various aberrations can be corrected. The spherical and aspherical lenses may be made of glass.

[0043] In the lenses of the optical system 100, the lens with the highest refractive index can be a spherical lens disposed between the aspherical lenses, and the lens with the highest Abbe number can be either the first lens 101 and 111 or the second lens 102 and 112. Therefore, because the lens with the highest refractive index is disposed between the aspherical lenses, it is easy to change the radius of curvature of the final lens and it is possible to suppress the increase in the effective diameter.

[0044] Within the optical system 100, the lens surface with the largest effective diameter can be positioned in the first lenses 101 and 111 closest to the object. The first lenses 101 and 111 can be made of glass and can be spherical lenses. Within the optical system 100, the lens with the smallest effective diameter can be positioned between the aperture stop ST and the first lenses 101 and 111. The lens with the smallest effective diameter can be an aspherical lens. Furthermore, the average effective diameter of the aspherical lens can be smaller than the average effective diameter of the spherical lens. Here, the effective diameter of the lens is the average of the effective diameters of the object-side surface and the sensor-side surface of each lens. By adjusting the effective diameter of each lens, the optical system 100 can be miniaturized.

[0045] Each of the lenses may include an effective region and an ineffective region. The effective region can be the area through which light incident on each lens passes. In other words, the effective region can be defined as the effective area or effective diameter through which incident light is refracted to achieve optical properties. Ineffective regions may be arranged around the effective regions. Ineffective regions can be areas where effective light is not incident on any of the lenses. In other words, ineffective regions can be areas unrelated to optical properties. Additionally, the ends of the ineffective regions may be areas fixed to a lens barrel (not shown) that houses the lenses.

[0046] In the lenses of the optical system 100, the lens with the largest center thickness can be a spherical lens, and the lens with the largest edge thickness can also be a spherical lens. The average center thickness of the spherical lens can be greater than the average center thickness of the aspherical lens. The total top length (TTL) can be reduced by using aspherical lenses with thinner thicknesses, and the incident light can be refracted into various paths.

[0047] In the optical system 100, the TTL can be greater than 10 times (ImgH), for example, greater than 10 times and less than 20 times. TTL is the distance along the optical axis OA from the center of the object-side surface of the first lenses 101 and 111 to the image surface of the sensing unit 151. ImgH is the distance from the center of the effective area of ​​the sensing unit 151 to its diagonal end, or half the maximum diagonal length of the effective area of ​​the sensing unit 151. Furthermore, the effective diameter of each lens in the optical system 100 can be greater than the diagonal length of the sensing unit 151. In the optical system 100, the effective focal length (EFL) is provided to be 15 mm or less, and the field of view (FOV) is provided to be 60 degrees or greater or 100 degrees or greater, enabling it to be provided as a standard receiving optical system in a vehicle sensor system. For example, the receiving optical system and sensor system according to the embodiment can be applied to sensing devices for ADAS (Advanced Driver Assistance Systems) installed inside or outside a vehicle.

[0048] Optical system 100 can meet the following condition: 5 <TTL / (2 The thickness of each lens along the optical axis OA is ≤10. Therefore, the center thickness of each lens can be increased, and the size of the sensing unit 151 can be reduced, thus providing an automotive lens optical system. Furthermore, temperature compensation is possible within a temperature range of -45°C to +120°C, a temperature reliability evaluation standard used for automotive electronic components used in automotive cameras. 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. The total effective focal length (EFL) can be 15mm or less, for example, in the range of 1mm to 15mm or 7mm to 13mm, and can be configured with lenses made of glass materials capable of the aforementioned temperature compensation. By shortening the effective focal length of the optical system, a wide angle can be achieved.

[0049] In optical system 100, the number of lenses with positive (+) refractive power can be equal to or greater than the number of lenses with negative (-) refractive power. The number of lenses with positive (+) refractive power can be 50% or more of the total number of lenses, for example, 55% or more. The average refractive index of lenses with negative refractive power can be less than the average refractive index of lenses with positive refractive power. The difference between the average refractive index of lenses with negative refractive power and the average refractive index of lenses with positive refractive power can be 0.5 or less, for example, 0.2 or less. The dispersion value of lenses with positive refractive power can be greater than the dispersion value of lenses with negative refractive power. Because optical system 100 combines spherical and aspherical lenses made of glass, it is possible to correct various aberrations, thereby preventing degradation of optical performance. In optical system 100, the ratio between the number of spherical lenses and the number of aspherical lenses can be equal to the ratio between the number of lenses with positive refractive power and the number of lenses with negative refractive power. Therefore, it is possible to correct various aberrations of optical system 100, thereby preventing degradation of optical performance.

[0050] Optical system 100 may include optical filter 155, and optical filter 155 may be disposed between two adjacent lenses. Optical filter 155 may be disposed between spherical lenses. Optical filter 155 may transmit light reflected from the subject after being emitted from the transmitting optical system, such as laser wavelength, and block other wavelengths. The transmitted laser wavelength may be in the range of 890 nm to 960 nm or 940 nm ± 10 nm. As another example, the laser wavelength may be in the range of 1550 nm ± 10 nm. Optical filter 155 may be a bandpass filter. Optical filter 155 may be disposed between two different lenses. Optical filter 155 may be disposed between spherical lenses. Optical filter 155 may be disposed between a third lens 103 and a fourth lens 104.

[0051] Optical filter 155 can perform the operation of allowing light of a specific wavelength (e.g., a wavelength range of approximately 800 nm to 1000 nm) or light belonging to a specific band to pass through, and blocking light outside the specific wavelength. Optical filter 155 can actively perform the filtering operation. For this purpose, optical filter 155 may include an active device that, in response to an external control signal, allows only light of a specific wavelength to pass through and blocks light of other wavelengths. The control signal provided to optical filter 155 may include information about the center wavelength of the light passing through the active device, wherein this center wavelength may correspond to the center wavelength of the light emitted from the transmitting optical system. Therefore, the control signal applied 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 passing 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 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 can include a tunable bandpass filter. The operation method of a tunable bandpass filter can be either liquid crystal method or acousto-optic method.

[0052] The optical filter 155 is a TOF optical system that uses a specific wavelength or designated band and can block light outside the designated band from being incident on the sensor unit, thereby suppressing stray light. Therefore, because at least one lens is disposed between the optical filter 155 and the sensing unit 151, the occurrence of stray light can be suppressed. That is, because visible light outside the designated band is blocked by the lens between the optical filter 155 and the sensing unit 151, the blocked visible light cannot be refracted, reflected, and / or scattered by the lens between the optical filter 155 and the sensing unit 151. The optical filter 155 can be a bandpass filter.

[0053] The optical system 100 and camera module can have an F-number of 1.5 or less. The F-number can range from 0.6 to 1.5, or from 0.65 to 0.9. In configuring such a bright optical system, the camera module can include at least five lenses and can be miniaturized and achieve good optical performance through at least one aspherical lens. The sum of the refractive indices of the lenses in the optical system 100 can be greater than 5, for example, greater than 8.0, preferably in the range of 8.0 to 12.0, and the average refractive index can be in the range of 1.70 to 1.82. The sum of the Abbe numbers of each lens can be less than or equal to 220, for example, in the range of 120 to 220 or 160 to 210, and the average Abbe number can be less than or equal to 47, for example, in the range of 23 to 47. By controlling the refractive indices of the lenses in the optical system 100, degradation of optical performance with temperature variations from -45 to 120°C can be prevented, and thermal compensation can be optimized. In addition, by controlling the Abbe number, the deviation in the size of the incident light spot can be minimized, that is, the size of the light spot pattern can be minimized.

[0054] The sum of the center thicknesses of all lenses in the optical system 100 can be 30 mm or greater, for example, in the range of 30 mm to 75 mm or 40 mm to 60 mm, and the average center thickness of each lens can be 15 mm or less, for example, in the range of 9 mm to 15 mm. The sum of the center distances between lenses in the optical axis OA can be 30 mm or greater, for example, in the range of 30 mm to 75 mm, and can be less than the sum of the center thicknesses of the lenses. Additionally, the average effective diameter of each lens surface in the optical system 100 can be provided as 50 mm or less, for example, in the range of 30 mm to 50 mm. By controlling the thickness of each lens in the optical system 100, degradation of optical performance for temperature variations from -45 to 120 degrees Celsius can be prevented, and thermal compensation can be optimized. In the optical system according to an embodiment of the invention, the field of view can be 110 degrees or greater, for example, in the range of 110 degrees or greater to 150 degrees, and preferably in the range of 120 degrees to 140 degrees. The diagonal length of the sensing unit 151 can be 14 mm or greater, for example, in the range of 14 mm to 22 mm or 18 mm ± 1 mm, and can be greater than the sensor height in the vertical direction. This invention provides an in-vehicle LIDAR device that suppresses changes in the focal imaging position due to temperature variations by stacking glass lenses and corrects various aberrations by providing aspherical lenses.

[0055] The embodiment includes an optical system applied to a LIDAR device, and the first lenses 101 and 111 can be provided as glass. This is because glass has the advantages of being scratch-resistant and insensitive to external temperatures compared to plastic materials. For placement inside a vehicle or to more effectively prevent scratches caused by foreign objects, glass lenses can be used as the first lenses 101 and 111, and the object-side surfaces of the first lenses 101 and 111 can have a convex shape so that external foreign objects do not accumulate. When the vehicle is in motion, the LIDAR device can detect the distance, orientation, speed, temperature, material distribution, and concentration characteristics of objects. Such a LIDAR device can be used in ADAS. The optical system 100 according to the embodiment may further include a reflective member (not shown) for changing the path of light. The reflective member can be implemented as a prism, which reflects incident light toward the lens. The optical system according to the embodiment will be described in detail below. When a lens with negative refractive power is the first lens group and a lens with positive refractive power is the second lens group, an aperture stop ST and an optical filter 155 can be arranged in 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.

[0056] An optical system according to a first embodiment of the present invention will be described.

[0057] Figure 1 This is a cross-sectional view of the receiving optical system of the LIDAR according to the first embodiment. Figure 2 It is shown Figure 1 A table showing the lens characteristics of the receiving 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 shown Figure 1 The curve of the diffraction MTF data of the receiving optical system, and Figure 5 It shows about Figure 1 A graph showing the aberration characteristics of the receiving optical system.

[0058] refer to Figures 1 to 3The optical system 100 may include a first lens 101, a second lens 102, a third lens 103, a fourth lens 104, and a fifth lens 105 aligned along the optical axis OA towards the sensor side, starting from the object side. The first to fifth lenses 101, 102, 103, 104, and 105 can be defined as lens units. The lens portion and the sensing unit 151 can be defined as a camera module, a sensor system, or a lens assembly. The optical system 100 may include an optical filter 155, and the optical filter 155 may be disposed between lenses. The optical filter 155 may be disposed between spherical lenses. The optical filter 155 may be disposed between aspherical lenses. The optical filter 155 may be disposed between spherical lenses disposed between aspherical lenses.

[0059] Light corresponding to the information of the object can pass through the first lens 101 to the third lens 103, the optical filter 155, and the fourth lens 104 and the fifth lens 105, and is incident on the sensing unit 151. An aperture stop ST can be placed around the sensor-side surface of the third lens 103. Each of the first lens 101 to the fifth lens 105 can have a positive (+) or negative (-) refractive power along the optical axis OA. At least one or all of the first lens 101 to the fifth lens 105 can comprise a plastic material or a glass material, and can be, for example, a glass material.

[0060] The first lens 101 may have a negative (-) refractive power. The first lens 101 may be made of glass. The first lens 101, made of glass, can reduce changes in its center position and radius of curvature due to temperature variations depending on the surrounding environment, and can protect the incident-side surface of the optical system 100. The first lens 101 is made of non-injection molded glass. The object-side first surface S1 of the first lens 101 may be convex, and the sensor-side second surface S2 may be concave. The first surface S1 and the second surface S2 may have spherical surfaces. The first lens 101 may have a meniscus shape convex toward the object side. Alternatively, the first surface S1 may have a concave shape in the optical axis OA, and the second surface S2 may have a convex shape. Alternatively, the first lens 101 may have concave shapes on both sides. Because the first surface S1 has a convex shape and the second surface S2 has a concave shape, the incident light can be refracted in a direction close to the optical axis OA, which can reduce the distance between the first lens 101 and the second lens 102, and reduce the effective diameter of the second lens 102. The shape of the lens surface of the first lens 101 can suppress the increase in the effective diameter of the second lens 102.

[0061] When the refractive index of the first lens 101 is Nd1, the following conditions can be satisfied: 1.7 < Nd1 or 1.75 < Nd1 < 2.1. Since the refractive index Nd1 of the first lens 101 is greater than the refractive index of the second lens 102 which is an aspherical surface, the radius of curvature of the first surface S1 of the first lens 101 can be increased, and the first lens and the second lens can be easily manufactured. If the refractive index Nd1 of the first lens 101 is less than this condition, the lens surface must be formed into a sharp concavity or convexity in order to increase the refractive power of the first lens 101 and the second lens 102. In this case, lens manufacturing is not simple, the lens defect rate increases, and this can cause a decrease in production volume.

[0062] The second lens 102 can be disposed between the first lens 101 and the third lens 103. The second lens 102 can face the sensor-side surface of the first lens 101 and the object-side surface of the third lens 103. The second lens 102 can have a negative (-) refractive power. The second lens 102 can be an aspherical lens made of glass. The object-side third surface S3 of the second lens 102 can be concave with respect to the optical axis OA, and the sensor-side fourth surface S4 can be concave. The third surface S3 and the fourth surface S4 can be aspherical, and as Figure 4 shown, the conic constants K of L2S1 and L2S2 and the aspherical coefficients from the 4th to the 14th order A - F are represented. The third surface S3 and the fourth surface S4 can be set to have no critical points from the optical axis OA to the end of the effective region. Alternatively, the third surface S3 can be convex, and the fourth surface S4 can be concave. Alternatively, the second lens 102 can be convex on both sides. When the refractive index of the second lens 102 is Nd2, the following conditions can be satisfied: 1.75 > Nd2 or 1.52 < Nd2 < 1.75. The refractive index Nd2 of the second lens 102 can be less than the refractive indices of the other lenses. The center distance between the second lens 102 and the third lens 103 can be increased by the shape of the second lens 102, and the center distance between the first lens 101 and the second lens 102 can be ensured.

[0063] The third lens 103 may have a positive (+) refractive power on the optical axis. The third lens 103 may include a glass material. The third lens 103 may be a spherical lens made of glass. The fifth surface S5 on the object side of the third lens 103 may be convex on the optical axis, and the sixth surface S6 on the sensor side may be convex. The third lens 103 may have a convex shape on both sides of the optical axis OA. Alternatively, the third lens 103 may have a convex meniscus shape on the object side or the sensor side. Alternatively, the third lens 103 may have a concave shape on both sides of the optical axis. At least one or both of the fifth surface S5 and the sixth surface S6 may be spherical. At least one or both of the fifth surface S5 and the sixth surface S6 may be set without a critical point from the optical axis OA to the end of the effective area. When the refractive index of the third lens 103 is Nd3, the following condition may be satisfied: Nd2 < Nd3. When the Abbe number of the third lens 103 is Vd3, the following condition may be satisfied: Vd3 < Vd2. Nd2 is the refractive index of the second lens 102, and Vd2 is the Abbe number of the second lens 102.

[0064] The aperture stop ST may be arranged around the sixth surface S6 on the sensor side of the third lens 103. Since the third lens 103 located on the object side of the aperture stop ST has a positive refractive power (F3 > 0), the third lens 103 can refract incident light in the direction of the optical axis, and compared with the third lens 103, it can suppress an increase in the effective diameter of the lens located on the sensor side. Therefore, it is possible to prevent the yield calculated by the weight of the optical system from decreasing due to the third lens 103, and the production efficiency can be improved. Here, the focal power of the fourth lens 104 and the fifth lens 105 located on the sensor side of the aperture stop ST can have a positive value, and the optical system can reduce the TTL within the viewing angle range.

[0065] The sixth surface S6 on the sensor side of the third lens 103 has a convex shape and a smaller radius of curvature than the fifth surface S5, so that the center distance between the third lens 103 and the aperture stop ST can be less than the center distance between the aperture stop ST and the fourth lens 104. The effective diameter of the optical filter 155 located on the sensor side of the third lens 103 can be less than the effective diameter of the sixth surface S6 of the third lens 103. The optical filter 155 transmits the laser beam reflected by the subject after being emitted from the transmitting optical system of the LIDAR device and blocks the light beams of other wavelengths. The optical filter 155 may be located closer to the third lens 103 than the fourth lens 104 to transmit the specified wavelength band and block the out-of-band wavelength band.

[0066] The fourth lens 104 may have positive (+) refractive power. The fourth lens 104 may comprise a glass material. The fourth lens 104 may be a spherical lens. The object-side seventh surface S7 of the fourth lens 104 on the optical axis may have a convex shape, and the sensor-side eighth surface S8 may have a concave shape. 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 sensor. Alternatively, the fourth lens 104 may have concave shapes on both sides of the optical axis OA. 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 may be configured to have no critical points from the end of the effective region along the optical axis OA.

[0067] The fifth lens 105 can have a positive (+) refractive power. The fifth lens 105 can comprise a glass material. The fifth lens 105 can be an aspherical lens. The object-side ninth surface S9 of the fifth lens 105 on the optical axis can have a convex shape, and the sensor-side tenth surface S10 can have a convex shape. The fifth lens 105 can have convex shapes on both sides. Alternatively, the fifth lens 105 can have a meniscus shape convex toward the object. Alternatively, the fifth lens 105 can have concave shapes on both sides. At least one or both of the ninth surface S9 and the tenth surface S10 can be aspherical. The aspheric coefficients of the ninth surface S9 and the tenth surface S10 can be provided as follows: Figure 3 L5S1 and L5S2. The fifth lens 105 can be an aspherical lens closest to the sensing unit 151. By means of a lens surface having an aspherical surface, aberrations such as spherical aberration and chromatic aberration can be improved, and the influence on resolution can be controlled. By means of an aspherical surface of a lens surface adjacent to the sensing unit 151, optical performance can be improved, and for example, aberration characteristics can be improved and resolution degradation can be prevented. The ninth surface S9 of the fifth lens 105 can be set to have no critical point from the end of the optical axis to the effective region, or can have at least one critical point. The tenth surface S10 can be set to have no critical point from the end of the optical axis to the effective region. Here, a critical point can mean a point where the sign of the slope value relative 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. In addition, a critical point can be a point where the slope value of the tangent through the lens surface increases and then decreases, or a point where it decreases and then increases.

[0068] When the refractive index of the fifth lens 105 is Nd5, the following condition can be satisfied: Nd5 < Nd4. When the Abbe number of the fifth lens 105 is Vd5, the following condition can be satisfied: Vd4 < Vd5. Nd4 is the refractive index of the fourth lens 104, and Vd4 is the Abbe number of the fourth lens 104. The first lens, the third lens, and the fourth lens 101, 103, and 104 can be made of the same material, or can be made of materials having a refractive index difference of 0.10 or less. The materials of the second lens and the fifth lens 102 and 105 are the same, or have a refractive index difference of 0.3 or less. The fifth lens 105 can have a lower refractive index than the third lens 103 and the fourth lens 104 and an Abbe number higher than those of the third lens 103 and the fourth lens 104.

[0069] The effective diameter of the fifth lens 105 can be smaller than the effective diameter of the fourth lens 104. The effective diameter of the first lens 101 can be the largest among all the lenses. The lens surface having the largest effective diameter among the object-side surfaces of the lenses can be the first surface S1, and the lens surface having the largest effective diameter among the sensor-side surfaces of the lenses can be the sixth surface S6. The lens surface having the smallest effective diameter among the object-side surfaces of the lenses can be the third surface S3, and the lens surface having the smallest effective diameter among the sensor-side surfaces of the lenses can be the fourth surface S4. Among the object-side surface and the sensor-side surface, the lens surface having the largest effective diameter can be the first surface S1, and the lens surface having the smallest effective diameter can be the third surface S3.

[0070] The effective diameter of the first lens 101 can be larger than the effective diameter of the fifth lens 105 closest to the sensing unit 151. Therefore, the brightness of the optical system 100 can be controlled. The first lens 101 and the second lens 102 can have negative focal power, and the third lens 103, the fourth lens 104, and the fifth lens 105 can have positive focal power. By controlling the effective diameter of each of the lenses 101 - 105, the optical system 100 can control the incident light to compensate for the deterioration of resolution and optical characteristics due to temperature changes, improve the chromatic aberration control characteristics, and improve the vignetting characteristics of the optical system 100. As another example, at least one of the object-side surface and the sensor-side surface of the second lens 102 and the fifth lens 105 can have a free-form surface, that is, a non-rotationally symmetric surface.

[0071] The optical filter 155 can transmit light, for example, a laser wavelength reflected from a subject after being emitted from the transmitting optical system, and block other wavelengths. The transmitted laser wavelength can be in the range of from 890 nm to 960 nm or 940 nm ± 10 nm. As another example, the laser wavelength can be in the range of 1550 nm ± 10 nm.

[0072] The third lens 103 can be disposed on the object side of the optical filter 155, having a refractive index greater than that of the second lens 102 and a center thickness CT3 greater than that of the first lens 101. The fourth lens 104 is disposed on the sensor side of the optical filter 155, having a refractive index greater than that of the fifth lens 105 and a center thickness CT5 greater than that of the first lens 101. The center distance CG3 between the third lens 103 and the fourth lens 104 can be greater than the thickness of the optical filter 155. The center distance CG2 between the second lens 102 and the third lens 103 can be greater than the center distance CG3 between the third lens 103 and the fourth lens 104 on which the optical filter 155 is disposed, and can be the largest among the center distances between two adjacent lenses in the optical system 100.

[0073] When the radius of curvature of each lens surface on the optical axis is described as an absolute value, the lens surface with the smallest radius of curvature can be the second surface S2 of the first lens 101. The lens surface with the largest radius of curvature can be the first surface S1 of the first lens 101. Therefore, the amount of incident light from the first lens 101 increases, and the center distance between the first lens 101 and the second lens 102 is the largest in the region between the first lens 101 and the second lens 102, making it possible to suppress the increase in the effective diameter of the second lens 102. The lens with the largest difference in radius of curvature between the object-side surface and the sensor-side surface of each lens is the first lens 101, and the lens with the second largest difference in radius of curvature is the third lens. Therefore, when adjusting the radii of curvature of the first lens 101 and the third lens 103, irregular reflections between adjacent lens surfaces can be prevented, thereby reducing lens ghosting and also preventing MPI (multipath interference) caused by lens ghosting. The first surface S1 on the object side of the first lens 101 is provided with a radius of curvature of 300 mm or greater, for example, greater than 20 times the radius of curvature of the second surface S2, which enables the distortion of reflected light to be reduced and the depth of field to be further increased, thereby improving image quality under low-light conditions.

[0074] The optical system 100 or sensor system may include a sensing unit 151. The sensing unit 151 is capable of detecting light that has sequentially 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 detects time delay or phase difference information from 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 may include a device capable of detecting incident light, such as an image sensor, for example, a CCD (charge-coupled device) or CMOS (complementary metal-oxide-semiconductor). 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 are no lenses with an effective diameter less than the effective length of the sensing unit 151.

[0075] At least two lenses can be disposed between the optical filter 155 and the sensing unit 151. For example, 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 a spherical third lens 103 and a spherical fourth lens 104. The optical filter 155 can be disposed between the sixth surface S6 of the third lens 103 and the seventh surface S7 of the fourth lens 104. For at least a portion of the wavelength range from 800 nm to 1000 nm, the optical filter 155 can have a transmittance of 90% or greater. The optical filter 155 can be, for example, a bandpass filter for laser beams ranging from 890 nm to 960 nm or 940 nm ± 10 nm. 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 above can pass the wavelength corresponding to the laser beam transmitted from the transmitting optical system of the LIDAR device, and block the light corresponding to the remaining ambient light.

[0076] The cover glass 153 is disposed between the final lens and the sensing unit 151, and can protect the upper part of the sensing unit 151 and prevent the reliability of the sensing unit 151 from deteriorating. The cover glass 153 can be removed. The cover glass 153 can be a protective glass.

[0077] The aperture stop ST can adjust the amount of light incident on the optical system 100. The aperture stop ST can be disposed on the periphery between the third lens 103 and the fourth lens 104. The aperture stop ST can be disposed on the periphery between the third lens 103 and the fourth lens 104. The aperture stop ST can be arranged to be closer to the sixth surface S6 of the third lens 103 than the seventh surface S7 of the fourth lens 104. The aperture stop ST can be disposed on the periphery between the third lens 103 and the optical filter 155.

[0078] The lens surface on which the aperture stop ST is disposed can more effectively control and guide the amount of light of the optical system 100. As in this embodiment, the aperture stop ST can be disposed on the sensor-side surface of the third lens 103 or the object-side surface of the optical filter 155. Alternatively, the aperture stop ST can be disposed on the periphery of the object-side surface or the sensor-side surface of the second lens 102. Alternatively, at least one lens selected from a plurality of lenses, for example, the object-side surface or the sensor-side surface of the third lens 103, can be used as the aperture stop.

[0079] As Figure 1 and Figure 2 As shown, the center thicknesses of the first lens 101 to the fifth lens 105 are represented by CT1-CT5, the edge thicknesses at the ends of the effective regions of each lens are represented by ET1-ET5, and the center distances (e.g., center gaps) between two adjacent lenses are represented by CG1-CG4. The first lens to the fifth lens 101-105 can satisfy the following conditions, and indicates multiplication.

[0080] Condition 1: CT1 < CT3 Condition 2: CT2 2 < CT5

[0081] Condition 3: (CT4 - CT5) < (CT3 - CT2) Condition 4: ET3 < ET2 < ET1

[0082] Condition 5: ET4 < ET2 < CT5

[0083] One of the central thicknesses CT3 and CT4 of the third lens 103 and the fourth lens 104 is the maximum among the central thicknesses of the lenses, and one of the central thicknesses CT1 and CT2 of the first lens 101 and the second lens 102 is the minimum among the central thicknesses of the lenses. Preferably, the central thickness CT3 of the third lens 103 is the maximum among the lenses, and the central thickness CT2 of the second lens 102 is the minimum among the lenses. The maximum central thickness can be greater than twice the minimum central thickness, and the difference between the maximum central thickness and the minimum central thickness can be 4 mm or more. That is, at least two of the central thicknesses of the spherical material lenses can be thinner than the central thickness of the last aspherical lens, enabling control of the thickness of the sensor system. By controlling the thicknesses of these lenses, thermal compensation can be performed for temperatures varying from low to high.

[0084] If the central distance CG between adjacent lenses is described, the following conditions can be satisfied.

[0085] Condition 1: CT1 < CG1 Condition 2: CG1 < CG2 < CG1 2

[0086] Condition 3: CG1 < CG3 < CG2 Condition 4: CG4 < CG1 < CG4 3

[0087] Condition 5: CT3 < CG2 Condition 6: CT2 2 < CG2

[0088] Condition 7: (CT1 + CT2) < CG2

[0089] Here, the difference between the maximum central distance and the minimum central distance can be 5 mm or greater, for example, within the range of 5 mm to 20 mm. Additionally, by providing the maximum central distance between the lenses to be greater than the maximum central thickness of each lens, a receiving optical system can be provided in which the central distance between the spherical lens and the aspherical lens does not increase. Further, since the maximum central distance between the lenses is provided as twice the minimum central thickness of each lens, the optical path can be controlled.

[0090] The effective diameter of each of the lenses 101 - 105 is CA1 - CA5. The effective diameters of the first surface S1 and the second surface S2 of the first lens 101 are CA11 and CA12, the effective diameters of the third surface S3 and the fourth surface S4 of the second lens 102 are CA21 and CA22, the effective diameters of the fifth surface S5 and the sixth surface S6 of the third lens 103 are CA31 and CA32, the effective diameters of the seventh surface S7 and the eighth surface S8 of the fourth lens 104 are CA41 and CA42, and the effective diameters of the ninth surface S9 and the tenth surface S10 of the fifth lens 105 are CA51 and CA52. The effective diameter of each lens can satisfy the following conditions.

[0091] Condition 1: CA12 < CA11 < CA12 Condition 2: CA2 < CA1

[0092] Condition 3: CA2 < CA3 Condition 4: 0.5 < CA21 / CA22 < 1.5

[0093] Condition 5: 0.5 < CA3 / CA4 < 1.5 Condition 6: 0.5 < CA32 / CA31 < 1.5

[0094] Condition 7: 0.5 < CA41 / CA42 < 1.5 Condition 8: 0.5 < CA51 / CA52 < 1.5

[0095] Condition 9: CA5 < CA4

[0096] The lens with the largest effective diameter can be the first lens 101. The first lens 101 with the largest effective diameter can be a spherical lens made of glass. The lens surface with the largest effective diameter can be the first surface S1 of the first lens 101. The lens with the smallest effective diameter can be the second lens 102 adjacent to the first lens 101. The lens surface with the smallest effective diameter can be the fourth surface S4 of the second lens 102, and can be less than 70% of the first surface S1. The effective diameter of each of the first lens 101 to the fifth lens 105 can be greater than the diagonal length of the effective area of the sensing unit 151. The fifth lens 105 has an aspherical surface and can guide the light incident through the fourth lens 104, which is a spherical lens, to the entire area of the sensing unit 151.

[0097] Figure 2 Yes Figure 1 An example of the lens data of the optical system of the embodiment. As Figure 2As shown, it is possible to set the radius of curvature of the first lens to the fifth lens 101, 102, 103, 104, and 105 on the optical axis OA, the center thickness CT of the lens, the center distance CG (e.g., center gap) between the lenses, the refractive index at the d line, the Abbe number, and the size of the effective diameter. As Figure 3 shown in Figure 1 Among the lenses of the embodiment of

[0098]

[0099] Condition 1: The refractive index of the lens with positive refractive power > the refractive index of the lens with negative refractive power

[0100] Condition 2: The dispersion of the lens with positive refractive power < the dispersion of the lens with negative refractive power

[0101] Here, among the lenses, the second lens 102 has negative refractive power and the third lens 103 has positive refractive power. Therefore, according to Condition 1 and Condition 2, the refractive index of the third lens 103 is greater than the refractive index of the second lens 102, and the dispersion value of the third lens 103 is less than the dispersion value of the second lens 102. The chromatic aberration that appears in the spherical lens can be corrected by the spherical lens. In addition, by satisfying a refractive index difference of 0.1 or less and an Abbe number difference of 10 or less between the third lens 103 and the fourth lens 104, which are consecutive spherical lenses, the chromatic aberration that appears in the spherical lens can be compensated by the spherical lens.

[0102] The refractive powers F1 - F5 of each lens and the total focal length F can satisfy the following conditions.

[0103] Condition 1: │F1│ < │F2│ Condition 2: │F1│ < F3

[0104] Condition 3: 0.5 < F3 / │F2│ < 1.5 Condition 4: F5 < F3 < F4

[0105] Condition 5: F < F5. Condition 6: F < │F1│

[0106] Condition 7: F < BFL

[0107] Here, F is the effective focal length of the optical system, and BFL is the distance along the optical axis from the last lens (i.e., the fifth lens 105) to the surface of the image sensor serving as the sensing unit 151. The focal length of the fourth lens 104 is the largest among all the lenses, and can be 50 mm or more and 100 mm or less. Therefore, it can have improved MTF characteristics, aberration control characteristics, resolution characteristics, etc. within the field of view set by the optical system, and can have good optical performance at the periphery of the field of view.

[0108] The combined focal length of the first lens and the second lens is F12, the combined focal length of the third lens to the fifth lens is F35, the combined focal length of the first lens to the third lens is F13, and the combined focal length of the fourth lens and the fifth lens is F45, and the following conditions can be satisfied.

[0109] Condition 1: │F12│ < F35 (F12 < 0). Condition 2: F45 < F13

[0110] Condition 3: F < F24 < F3

[0111] Here, F is the total focal length, and F24 is the combined focal length of the second lens to the fourth lens.

[0112] TTL is the distance along the optical axis from the object-side surface of the first lens 101 to the surface of the sensing unit 151, and FOV is the field of view of the optical system. TTL and FOV can satisfy the following conditions.

[0113] Condition 1: CA11 2 < TTL. Condition 2: F4 < TTL

[0114] Condition 3: 0.5 < TTL / FOV < 1.5

[0115] Figure 4 is a graph showing Figure 1 the diffraction MTF in the optical system, and is a graph showing the modulation according to the spatial frequency luminance. That is, Figure 4 shows the diffraction MTF at room temperature, and is a graph measuring the luminance ratio according to the defocus position. Figure 5 is a graph showing Figure 1 the aberration characteristics in the optical system. Figure 5 The graph is a graph measuring the longitudinal spherical aberration, astigmatism field curve, and distortion from left to right. At Figure 5In the graph, the X-axis represents focal length (mm) and distortion (%), while the Y-axis represents image height. Additionally, the graphs for spherical aberration are for light in the approximately 930nm, 940nm, and 950nm wavelength ranges, and the graphs for astigmatism and distortion are for light in the approximately 940nm wavelength range. Figure 5 In the aberration diagram, at room temperature, the closer each curve is to the Y-axis, the better the aberration correction function. That is, the optical system 100 according to this embodiment has improved resolution and good optical performance in the center and periphery of the field of view (FOV).

[0116] An optical system according to a second embodiment of the present invention will be described. In explaining the second embodiment, the same configuration as in the first embodiment will be referred to the explanation of the first embodiment. Figure 6 This is a cross-sectional view of the receiving optical system of a LIDAR according to the second embodiment. Figure 7 It is shown Figure 6 The lens characteristics of the receiving optical system, Figure 8 It is shown Figure 6 A table of aspherical coefficients of lenses in a receiving optical system. Figure 9 It is shown Figure 6 The curve of the diffraction MTF data of the receiving optical system, and Figure 10 It shows about Figure 6 A graph showing the aberration characteristics of the receiving optical system.

[0117] refer to Figures 6 to 8 The optical system 100 may include a first lens 111, a second lens 112, a third lens 113, an optical filter 155, a fourth lens 114, and a fifth lens 115. Each of the first lenses 111 to the fifth lens 115 may have a positive (+) or negative (-) refractive power along the optical axis OA. At least one or all of the first lenses 111 to the fifth lens 115 may include a plastic material or a glass material, and for example, the first lenses 111 to the fifth lens 115 may be made of glass. The first lens 111 and the second lens 112 may have a negative refractive power. The third lens 113, the fourth lens 114, and the fifth lens 115 may have a positive refractive power.

[0118] The first surface S1 on the object side of the first lens 111 may be convex, and the second surface S2 on the sensor side may be concave. The first surface S1 and the second surface S2 may have spherical surfaces. When the refractive index of the first lens 111 is Nd1, the following conditions may be satisfied: 1.7 < Nd1 or 1.75 < Nd1 < 2.1. The second lens 112 may be an aspherical lens made of glass. The third surface S3 on the object side of the second lens 112 may be concave, and the fourth surface S4 on the sensor side may be concave. The third surface and the fourth surface (S3, S4) may be aspherical and represent the conic constant K of L2S1 and L2S2 and the aspherical coefficients A - F from the 4th to the 14th order as shown in Figure 9 . When the refractive index of the second lens 112 is Nd2, the following conditions may be satisfied: 1.75 > Nd2 or 1.52 < Nd2 < 1.75. By the shape of the second lens 112, the center distance between the second lens 112 and the third lens 113 can be increased, and the center distance between the first lens 111 and the second lens 112 can be ensured.

[0119] The third lens 113 may be a spherical lens made of glass. The fifth surface S5 on the object side of the third lens 113 may be convex, and the sixth surface S6 on the sensor side may be convex. At least one or both of the fifth surface S5 and the sixth surface S6 may be spherical. When the refractive index of the third lens 113 is Nd3, the following condition may be satisfied: Nd2 < Nd3. When the Abbe number of the third lens 113 is Vd3, the following condition may be satisfied: Vd3 < Vd2. The aperture stop ST may be arranged around the sixth surface S6 on the sensor side of the third lens 113. The aperture stop ST may be provided between the third lens 113 and the fourth lens 114. The aperture stop ST may be provided between the third lens 113 and the optical filter 155.

[0120] Since the sixth surface S6 on the sensor side of the third lens 113 has a convex shape and has a smaller radius of curvature than the fifth surface S5, the center distance between the third lens 113 and the aperture stop ST can be less than the center distance between the aperture stop ST and the fourth lens 114. The effective diameter of the optical filter 155 located on the sensor side of the third lens 113 can be less than the effective diameter of the sixth surface S6 of the third lens 113.

[0121] The fourth lens 114 may be a spherical lens. The seventh surface S7 on the object side of the fourth lens 114 may have a convex shape, and the eighth surface S8 on the sensor side may have a concave shape. At least one or both of the seventh surface S7 and the eighth surface S8 may be spherical. The fifth lens 115 may be an aspherical lens. The ninth surface S9 on the object side of the fifth lens 115 may have a convex shape with respect to the optical axis, and the tenth surface S10 on the sensor side may have a convex shape. The fifth lens 115 may have a convex shape on both sides. The aspherical coefficients of the ninth surface S9 and the tenth surface S10 may be provided as Figure 8 L5S1 and L5S2 of Figure 8 . The fifth lens 115 may be the aspherical lens closest to the sensing unit 151. By having a lens surface with an aspherical surface, it is possible to improve aberrations such as spherical aberration and chromatic aberration, and to control the influence on resolution. By the aspherical surface of the lens surface adjacent to the sensing unit 151, the optical performance can be improved. For example, the aberration characteristics can be improved and the resolution degradation can be prevented. The ninth surface S9 of the fifth lens 115 may be set to have no critical point from the optical axis to the end of the effective region, or may be able to have at least one critical point. The tenth surface S10 may be set to have no critical point from the optical axis to the end of the effective region.

[0122] When the refractive index of the fifth lens 115 is Nd five, the following condition may be satisfied: Nd five < Nd four. When the Abbe number of the fifth lens 115 is Vd five, the following condition may be satisfied: Vd four < Vd five. The first lens 111, the third lens 113, and the fourth lens 114 may be made of the same material, or made of materials having a refractive index difference of 0.15 or less. The materials of the second lens 112 and the fifth lens 115 may be the same, or have a refractive index difference of 0.3 or less. The fifth lens 115 may have a refractive index lower than that of the third lens 113 and the fourth lens 114, and may have an Abbe number higher than that of the third lens 113 and the fourth lens 114.

[0123] The effective diameter of the fifth lens 115 may be smaller than the effective diameter of the fourth lens 114. The effective diameter of the third lens 113 may be the largest among all the lenses. Among the lens surfaces on the object side of the lens, the lens surface having the largest effective diameter may be the seventh surface S7, and among the lens surfaces on the sensor side of the lens, the lens surface having the largest effective diameter may be the sixth surface S6. Among the lens surfaces on the object side of the lens, the lens surface having the smallest effective diameter may be the third surface S3, and among the lens surfaces on the sensor side of the lens, the lens surface having the smallest effective diameter may be the tenth surface S10. Among the object side surface and the sensor side surface, the lens surface having the largest effective diameter may be the sixth surface S6 or the seventh surface S7, and the lens surface having the smallest effective diameter may be the tenth surface S10.

[0124] The effective diameter of the first lens 111 can be larger than the effective diameter of the fifth lens 115, 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 of the lenses 111-115, the optical system 100 can control the incident light to compensate for the degradation of resolution and optical characteristics caused by temperature changes, improve chromatic aberration control characteristics, and improve the vignetting characteristics of the optical system 100. As another example, at least one of the object-side surface and sensor-side surface of the second lens 112 and the fifth lens 115 can have a free-form surface, i.e., a non-rotationally symmetric surface.

[0125] The third lens 113 is disposed on the object side of the optical filter 155, has a refractive index greater than that of the second lens 112, and may have a center thickness CT3 greater than that of the first lens 111. The fourth lens 114 is disposed on the sensor side of the optical filter 155, has a refractive index greater than that of the fifth lens 115, and has a center thickness CT5 greater than that of the first lens 111. Because the optical filter 155 is disposed closer to the object than the fifth lens 115, the incident angle of light can be adjusted, and the occurrence of stray light can be suppressed. The center distance CG2 between the second lens 112 and the third lens 113 is greater than the center distance CG3 between the third lens 113 and the fourth lens 114 on which the optical filter 155 is disposed, and may be the largest among the center distances between two adjacent lenses in the optical system 100.

[0126] When the radius of curvature of each lens surface on the optical axis is described as an absolute value, the lens surface with the smallest radius of curvature can be the second surface S2 of the first lens 111. Because the radius of curvature of the first surface S1 of the first lens 111 is provided to be 300 mm or greater, the amount of incident light from the first lens 111 increases, and the center distance between the first lens 111 and the second lens 112 is the largest in the region between the first lens 111 and the second lens 112, thus suppressing the increase in the effective diameter of the second lens 112. Alternatively, the lens surface with the largest radius of curvature can be the tenth surface S10 of the fifth lens 115. Therefore, the size of the sensing unit 151 can be maintained without increasing, and the fifth lens 115 can refract light across the entire region of the sensing unit 151. The lens with the largest absolute difference in radius of curvature between the object-side surface and the sensor-side surface of each lens is the fifth lens 115, and the second largest lens is the first lens 111. The object-side first surface S1 of the first lens 111 has a radius of curvature of 300 mm or greater, which is provided to be 20 times larger than the radius of curvature of the second surface S2, thereby reducing the distortion of reflected light and further increasing the depth of field, thus improving image quality under low-light conditions.

[0127] At least two lenses may be disposed between the optical filter 155 and the sensing unit 151. For example, the fourth lens 114 and the fifth lens 115 may be disposed between the optical filter 155 and the sensing unit 151. Spherical lenses and aspherical lenses may be disposed between the optical filter 155 and the sensing unit 151. The optical filter 155 may be disposed between the spherical third lens 113 and the spherical fourth lens 114. The cover glass 153 is disposed between the last lens and the sensing unit 151, protects the upper part of the sensing unit 151, and prevents deterioration of the reliability of the sensing unit 151.

[0128] As Figure 6 and Figure 7 shown, the first lens 111 to the fifth lens 115 may satisfy the following conditions, and represents multiplication. <00E0342>

[0129] Condition 1: CT1 < CT3 Condition 2: CT2 2 < CT5

[0130] Condition 3: (CT4 - CT5) < (CT3 - CT2) Condition 4: ET3 < ET2 < ET1

[0131] Condition 5: ET4 < ET2 < CT5

[0132] The central thickness CT4 of the fourth lens 114 is the largest among the lenses, and the central thickness CT1 of the first lens 111 is the smallest among the lenses. The largest central thickness may be greater than twice the smallest central thickness, and the difference between the largest central thickness and the smallest central thickness may be 4 mm or more. That is, at least two of the central thicknesses of the spherical material lenses may be thinner than the central thickness of the last aspherical lens, so that the thickness of the sensor system can be adjusted. By adjusting the thicknesses of these lenses, thermal compensation can be performed for temperatures changing from low to high.

[0133] If the central distance CG between adjacent lenses is described, the following conditions may be satisfied.

[0134] Condition 1: CT1 < CG1 Condition 2: CG1 < CG2 < CG1 3

[0135] [[ID=3S]]Condition 3: CG1 < CG3 < CG2 Condition 4: CG4 < CG1 < CG4 2

[0136] Condition 5: CT3 < CG2 Condition 6: CT2 2 < CG2

[0137] Condition 7: (CT1 + CT2) < CT4 < CG2

[0138] Here, the difference between the maximum center distance and the minimum center distance can be 5 mm or greater, for example, within the range of 5 mm to 20 mm. Additionally, by providing the maximum center distance between the lenses to be greater than the maximum center thickness of each lens, an optical receiving system can be provided in which the center distance between the spherical lens and the aspherical lens does not increase. Additionally, since the maximum center distance between the lenses is provided to be twice the minimum center thickness of each lens, the optical path can be controlled.

[0139] The effective diameter of each lens can satisfy the following conditions.

[0140] Condition 1: CA12 < CA11 < CA12 2 Condition 2: CA2 < CA1

[0141] Condition 3: CA1 < CA3 Condition 4: 0.5 < CA21 / CA22 < 1.5

[0142] Condition 5: 0.5 < CA3 / CA4 < 1.5 Condition 6: 0.5 < CA32 / CA31 < 1.5

[0143] Condition 7: 0.5 < CA41 / CA42 < 1.5 Condition 8: 0.5 < CA51 / CA52 < 1.5

[0144] Condition 9: CA5 < CA4

[0145] The lens with the maximum effective diameter can be the third lens 113. The lens surface with the maximum effective diameter can be the sixth surface S6 of the third lens 113. The lens with the minimum effective diameter can be the second lens 112. The lens surface with the minimum effective diameter can be the tenth surface S10 of the fifth lens 115 and can be less than 75% of the sixth surface S6. The effective diameter of each of the first lens 111 to the fifth lens 115 can be greater than the diagonal length of the effective area of the sensing unit 151. The fifth lens 115 has an aspherical surface and can guide the light incident through the fourth lens 114, which is a spherical lens, to the entire area of the sensing unit 151.

[0146] Figure 7 is Figure 6 an example of the lens data of the optical system of the embodiment. As Figure 7 shown, the radius of curvature of the optical axis OA of the first lens to the fifth lens 111, 112, 113, 114, and 115, the center thickness CT of the lens, the center distance CG between the lenses, the refractive index at the d line, the Abbe number, and the size of the effective diameter can be set. As Figure 8 shown, in Figure 6Among the lenses of the embodiments, the lens surfaces of the second lens 112 and the fifth lens 115 may include aspherical surfaces having a radius of curvature R, a conic constant K, and 14th-order aspherical coefficients A-E. For example, the object-side surface and the sensor-side surface of the second lens 112 and the fifth lens 115 may be lens surfaces having 14th-order aspherical coefficients. The focal lengths F1 and F2 of the first lens 111 and the second lens 112 may have negative refractive powers, and the focal lengths F3, F4, and F5 of the third lens 113, the fourth lens 114, and the fifth lens 115 may have positive refractive powers. The refractive powers F1-F5 of each lens and the total focal length F may satisfy the following conditions.

[0147] Condition 1: │F1│ < │F2│ Condition 2: │F2│ < F3

[0148] Condition 3: 0.5 < F3 / │F2│ < 1.5 Condition 4: F5 < F4

[0149] Condition 5: F < F5 Condition 6: F < │F1│

[0150] Condition 7: F < BFL

[0151] Here, the focal length of the fourth lens 114 is the maximum among the lenses and may be 45 mm or more and 100 mm or less. Therefore, it may have improved MTF characteristics, aberration control characteristics, resolution characteristics, etc. within the field of view set by the optical system, and may have good optical performance in the periphery of the field of view. In addition, the composite focal length may satisfy the following conditions.

[0152] Condition 1: │F12│ < F35 (F12 < 0) Condition 2: F45 < │F13│ (F13 < 0)

[0153] Condition 3: F < F24 < F3

[0154] TTL and FOV may satisfy the following conditions.

[0155] Condition 1: CA11 2 < TTL

[0156] Condition 2: F4 < TTL

[0157] Condition 3: 0.5 < TTL / FOV < 1.5

[0158] Figure 9 is a graph showing the diffraction MTF in the Figure 6 optical system and is a graph showing the modulation according to the spatial frequency luminance. That is, Figure 9 shows the diffraction MTF at room temperature and is a graph measuring the modulation of luminance according to the defocus position.

[0159] Figure 10 It is shown Figure 6 A graph showing the aberration characteristics in an optical system. Figure 10 The graph is a graph measuring longitudinal spherical aberration, astigmatism, and distortion from left to right. Figure 10 In the graph, the X-axis represents focal length (mm) and distortion (%), while the Y-axis represents the image height. Additionally, the graphs for spherical aberration are for light in the approximately 930 nm, 940 nm, and 950 nm wavelength ranges, and the graphs for astigmatism and distortion aberrations are for light in the approximately 940 nm wavelength range. Figure 10 In the aberration diagram, at room temperature, the closer each curve is to the Y-axis, the better the aberration correction can be interpreted. That is, the optical system 100 according to this embodiment can have improved resolution and good optical performance in both the center and periphery of the field of view (FOV).

[0160] The optical system 100 according to the first and second embodiments generates chromatic aberration and can correct it using spaced aspherical lenses. The lenses repeatedly contract and expand as the temperature changes from low to high. Because the lens properties of lenses made of the same material change by the same amount with temperature changes, correcting chromatic aberration between lenses of the same material is effective even when the temperature changes. Furthermore, the optical system 100 can compensate for temperature variations in aspherical lenses, even when using at least one or two or more aspherical lenses, and can prevent degradation of the reliability of optical properties. The optical system of the above embodiments can effectively control aberration characteristics such as chromatic aberration and distortion aberration, and can have good optical performance at the center and periphery of the field of view (FOV).

[0161] The receiving optical systems according to the first and second embodiments of the present invention can prevent the deterioration of optical performance from low temperature to high temperature by considering the characteristics of vehicle optical systems. For example, after designing the lenses at room temperature, the values of dn / dt as the temperature-dependent refractive index change coefficients are assembled by considering the focal power combinations of each lens, and the value of the temperature coefficient (dn / dt) of defocus for the refractive index of the lens and the thickness variable at low temperature, room temperature, and high temperature can be set to 5 μm or less. For this purpose, the first lens, the third lens, and the fourth lens are made of spherical glass, and the second lens and the fifth lens are made of aspherical glass. An existing filter is provided between the sensing unit and the last lens. In an embodiment of the present invention, the optical filter 155 can be arranged close to the aperture stop ST, that is, between the aperture stop ST and the third lenses 103 and 113. Therefore, the incident angle of light incident on the optical filter 155 can be minimized. For example, at the 0 field (0 F) inspected by an AOI device, the incident angle (AOI) of the principal beam at the incident surface of the optical filter 155 can be less than 20 degrees, for example, 0.6 degrees or less, and the incident angle of the principal beam at the image sensor can be less than 50 degrees or less. Therefore, the problem of the incident angle displacement of the principal beam can be minimized.

[0162] The optical system 100 according to the embodiment disclosed above can satisfy at least one or two or more of the following equations. Therefore, the optical system 100 according to the embodiment disclosed can have improved optical characteristics. For example, when the optical system 100 satisfies at least one equation, the optical system 100 can effectively control aberration characteristics such as chromatic aberration and distortion aberration, and can have good optical performance at the center and periphery of the FOV. In addition, the optical system 100 can have improved resolution. In addition, the meanings of the thickness of the lens on the optical axis OA and the distance between adjacent lenses on the optical axis OA described in the equations can be referred to the above embodiments.

[0163] [Equation 1] 0 < CT1 / CT2 < 3

[0164] In Equation 1, by setting the center thickness CT1 of the first lenses 101 and 111 and the center thickness CT2 of the second lenses 102 and 112, the stiffness of the first lenses 101 and 111 can be prevented from deteriorating, and the factors affecting aberration can be controlled. Preferably, Equation 1 can be satisfied: 1 < CT1 / CT2 < 2 (first embodiment) or 0.5 < CT1 / CT2 < 1 (second embodiment).

[0165] [Equation 2] 3 < CA11 / CT1

[0166] In Equation 2, the central thickness CT1 of the first lenses 101 and 111 and the effective diameter CA11 of the object-side surfaces S1 of the first lenses 101 and 111 can be set, and if this is satisfied, the strength and optical properties of the glass lens can be prevented from being deteriorated. If it is below the range of Equation 1, the lens may be damaged or the incident efficiency may decrease, and if it is greater than the above range, the TTL may increase and the weight of the optical system may become heavier. Preferably, Equation 2 can satisfy: 3 < CA11 / CT1 < 10 (First Embodiment) or 10 < CA11 / CT1 < 25 (First Embodiment).

[0167] [Equation 3] 0 < CT5 / CT4 < 2

[0168] In Equation 3, the central thickness CT5 of the fifth lenses 105 and 115 and the central thickness CT4 of the fourth lenses 104 and 114 can be set so that thermal compensation can be optimized according to the temperature change from low temperature to high temperature, and optical performance degradation can be prevented. Preferably, Equation 3 can satisfy: 0.5 < CT5 / CT4 < 1.5.

[0169] [Equation 4] 0 < CT5 / (CT1 + CT2) < 2.5

[0170] In Equation 4, the central thickness CT5 of the fifth lens is set to 0.5 times the sum of the central thicknesses CT1 and CT2 of the first lens and the second lens, so that the light refracted from the fifth lenses 105 and 115 is guided to the sensing unit 151. Preferably, Equation 4 can satisfy: 0.5 < CT5 / (CT1 + CT2) < 1.5 (First Embodiment) or 1 < CT5 / (CT1 + CT2) < 2.5 (Second Embodiment). Therefore, the central thickness CT5 of the fifth lenses 105 and 115 closest to the sensing unit 151 can be set to be thicker than the central thickness CT1 of the first lenses 101 and 111, and the effective diameter can be set to be smaller than the effective diameter of the first lens.

[0171] [Equation 5] 1 < CG3 / CT2 < 5

[0172] In Equation 5, the central distance CG3 between the third lens and the fourth lens can be set to be greater than the central thickness CT2 of the second lens. Therefore, the third lenses 103 and 113 can ensure a space for mounting the optical filter 155 between the convex sensor-side surface and the convex object-side surface of the fourth lenses 104 and 114. The effective diameter of the third lens 103 can be set to be greater than the effective diameter of the second lens 102. Preferably, Equation 5 can satisfy: 2 < CG3 / CT2 < 3.

[0173] [Equation 6] 0 < CG4 / CG1 < 1

[0174] In Equation 6, the center distance between the spherical lens and the aspherical lens can be set by setting the center distance CG1 between the first lens and the second lens, and the center distance CG4 between the fourth lens and the fifth lens. Preferably, 0.3 can be satisfied. <CG4 / CG1<1。

[0175] [Equation 6-1] 0 <CG4 / CG2<1

[0176] In Equation 6-1, by setting the center distance CG2 between the second and third lenses to be greater than the center distance CG4 between the fourth and fifth lenses, the center distance CG2 between two adjacent lenses on the object side of the aperture stop ST can be set to be greater than the center distance CG4 between two lenses on the sensor side of the aperture stop ST. Therefore, the optical paths on the incident and exit sides of the aperture stop ST can be adjusted. Preferably, Equation 6-1 satisfies: 0.1 <CG4 / CG2<0.5。

[0177] [Equation 7] 5 <CG3 / OFt

[0178] In Equation 7, OFt is the thickness of the optical filter 155, and can be less than the center distance CG3 between the third lens and the fourth lens. In Equation 7, the space available for mounting the optical filter 155 can be ensured by the center distance CG3 between the third lens 103 and the fourth lens 104. Preferably, Equation 5 satisfies: <CG3 / OFt<15。

[0179] [Equation 8] CG1 <CG3<CG2

[0180] In Equation 8, the center distances CG1, CG2, and CG3 between the first lens and the fourth lens can be set. Therefore, the first lens 101 has a crescent shape that convexes toward the object, and the second lens 102 has concave shapes on both sides, so that gaps can be set.

[0181] [Equation 9] 5 <TTL / CT_AVER<25

[0182] In Equation 9, CT_AVER is the average center thickness of the first to fifth lenses, and the total optical axis length (TTL) and center thickness of the lenses can be set. Therefore, the center thickness of six or fewer glass lenses can be set according to the optical axis length.

[0183] [Equation 10] 1.70 <Nd1

[0184] Nd1 is the refractive index of the d-line of the first lenses 101 and 111. In Equation 10, by setting the refractive indices of the first lenses 101 and 111 to be high, factors affecting the reduction of the third aberration (Seidel aberration) of the optical system can be adjusted, and the aberration that may occur when the TTL is slightly longer can be reduced. Equation 10 preferably satisfies 1.75 < Nd1 < 2.1. If it is designed to be lower than the lower limit of Equation 10, the performance of reducing aberration can be obtained, but because the refractive power of the first lens is weakened, light cannot be effectively collected, and the performance of the optical system can be degraded. If it is designed to be higher than the upper limit of Equation 10, there are disadvantages in obtaining materials. In addition, if the refractive indices of the first lenses 101 and 111 are designed to be lower than the lower limit of Equation 10, the radii of curvature of the first lens and the second lens can be increased to facilitate increasing the refractive power of the first lens and the second lens.

[0185] [Equation 10-1] 1.72 ≤ Aver(Nd1:Nd5) ≤ 1.80

[0186] Aver(Nd1:Nd5) is the average value of the refractive index values of the d-line of the first lens to the fifth lens. When Equation 10-1 is satisfied, the optical system 100 can set the resolution and suppress the influence on the TTL.

[0187] [Equation 10-2] GM_Nd_Aver < GL_Nd_Aver

[0188] GL_Nd_Aver is the average value of the refractive index values of the d-line of the spherical glass lenses, and GM_Nd_Aver is the average value of the refractive index values of the aspherical glass lenses, and they are both glass molds. The spherical lens is a lens made of a glass material formed by non-injection molding, and the aspherical lens is a lens made of a glass material formed by injection molding. The spherical lens with a high refractive index is positioned on the object side of the aspherical lens so that chromatic dispersion can be controlled.

[0189] [Equation 11] 0 < Nd1 / Nd3 < 1.5

[0190] Nd1 and Nd3 are the refractive indices of the first lens and the third lens at the d-line. In Equation 11, the difference in refractive indices between the first lens and the third lens can be reduced, thereby preventing the degradation of chromatic dispersion caused by the lens made of glass. Preferably, Equation 11 can satisfy: Nd1 < Nd3.

[0191] [Equation 12] 1 < Nd3 / Nd2 < 1.5

[0192] Nd3 and Nd4 are the refractive indices of the second and third lenses at the d-line. In Equation 12, the refractive index of the third lens is set to be higher than that of the second lens, making it possible to control the dispersion caused by the lens made of spherical material and the dispersion caused by the aspherical lens. Preferably, Equation 12 can satisfy: 1 <Nd3 / Nd2<1.3。

[0193] [Equation 13] (Vd4) Nd4) < (Vd2) Nd2)

[0194] Vd2 and Vd4 are the Abbe numbers of the second and fourth lenses, respectively. In Equation 13, the product of the refractive index of the second lens 102 and the Abbe number is set to be greater than the product of the refractive index of the fourth lens 104 and the Abbe number, so that dispersion caused by spherical material lenses and dispersion caused by aspherical lenses can be controlled.

[0195] [Formula 13-1] (Vd3 Nd3) < (Vd5) Nd5)

[0196] Vd3 and Vd5 are the Abbe numbers of the third and fifth lenses, respectively. In Equation 13-1, the product of the refractive index of the fifth lens 105 and the Abbe number is set to be greater than the product of the refractive index of the third lens 103 and the Abbe number, thereby enabling control over the dispersion caused by spherical material lenses and the dispersion caused by aspherical lenses.

[0197] [Equation 14] 2 <D1 / BFL<6

[0198] BFL is the optical axis distance from the surface of the sensing unit 151 to the center of the sensor-side surface of the last lens (i.e., the fifth lens 105), and D1 is the optical axis distance from the surface of the sensing unit 151 to the sensor-side surface of the optical filter 155. By satisfying Equation 14, the optical filter 155 can be configured to be adjacent to the aperture stop ST, or positioned between lenses closer to the object side than the last lens.

[0199] [Equation 14-1] 1 <SD / D1<1.2

[0200] SD is the distance along the optical axis from the aperture stop ST to the surface of the sensing unit 151. If Equation 14-1 is satisfied, the optical filter 155 can be set to be closer to the sensor side than the aperture stop ST.

[0201] [Equation 14-2] 0.5 <BFL / CG3<1.5

[0202] If Equation 14-2 is satisfied, the optical filter 155 is placed in the gap between the third lens and the fourth lens, and the optical axis distance (BFL) between the final lens and the sensing unit can be increased.

[0203] [Equation 15] CT5 3 <D1<CT5 5

[0204] In Equation 15, the optical axis distance D1 from the surface of the sensing unit 151 to the sensor-side surface of the optical filter 155 can be set to be greater than three times the center thickness CT5 of the fifth lenses 105 and 115. Therefore, the incident angle of the main beam incident on the optical filter 155 can be reduced to less than 20 degrees, and the problem of incident angle displacement at low and high temperatures compared to room temperature can be minimized. Here, the center thickness CT5 of the fifth lens can be greater than the total focal length F. That is, satisfying F... <CT5。

[0205] [Equation 16] 0.5 <D1 / D2<1.5

[0206] D2 is the optical axis distance from the center of the object-side surface of the first lens 101 to the object-side surface of the optical filter 155. If Equation 16 is satisfied, the optical filter 155 can be positioned between the lenses, or between the third and fourth lenses, 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 20 degrees, and the problem of incident angle displacement at low and high temperatures compared to room temperature can be minimized. Preferably, D1 can be satisfied. <D2。

[0207] [Equation 17] 0.5 <D1 / CA_Max<1.5

[0208] CA_Max is the maximum effective diameter between the object-side surface and the sensor-side surface of the lens. Equation 17 can set the position of the optical filter and the maximum effective diameter. Preferably, Equation 17 can satisfy 1 <D1 / CA_Max<1.5。

[0209] [Equation 18] 1 <CA11 / CA21<5

[0210] CA11 refers to the effective diameter of the first surface S1 of the first lens 101, and CA21 refers to the effective diameter of the third surface S3 of the second lens 102. When Equation 18 is satisfied, the optical system 100 can control the incident light and set the factors affecting aberrations, and preferably, it can satisfy 1. <CA11 / CA21<2.5。

[0211] [Equation 19] 0 <CA22 / CA31<2

[0212] CA22 refers to the effective diameter of the fourth surface S4 of the second lens, and CA31 refers to the effective diameter of the fifth surface S5 of the third lens. When Equation 19 is satisfied, the optical system 100 can control the incident light path and set the sensor-side surface of the second lens to a concave shape. Preferably, Equation 19 can satisfy 0.5 <CA22 / CA31<1。

[0213] [Equation 20] 0.5 <CA42 / CA51<2

[0214] CA42 refers to the effective diameter of the eighth surface S8 of the fourth lens, and CA51 refers to the effective diameter of the ninth surface S9 of the fifth lens. When Equation 20 is satisfied, the optical system 100 can be configured to provide an optical path that passes through the fourth lens 104 and the fifth lens 105 and is incident on the sensing unit 151. Equation 20 can preferably satisfy: 1 <CA42 / CA51<1.5。

[0215] [Equation 21] 1 <CA11 / CA52<5

[0216] CA11 is the effective diameter of the first surface S1 of the first lens, and CA52 refers to the effective diameter of the tenth surface S10 of the fifth lens. When the optical system 100 satisfies Equation 21, the incident light amount of the first lens, which is a spherical lens, can be increased, and the path of light toward the sensing unit can be set by the last lens, which is an aspherical lens. Equation 21 can preferably satisfy: 1 <CA11 / CA52<2.5。

[0217] [Equation 22] 50 <TTL / Nd1<100

[0218] In Equation 22, the total optical axis length (TTL) and refractive index of the first lens can be set. When Equation 22 is satisfied, the total optical axis length can be set to be more than 50 times the refractive index of the first lens. Preferably, Equation 22 can satisfy: 55 <TTL / Nd1<90。

[0219] [Equation 23] 20 <CA11 / Nd1<40

[0220] In Equation 23, the effective diameter of the first surface S1 on the object side of the first lens and the refractive index of the first lens can be set. If Equation 23 is satisfied, the effective diameter of the first surface can be set to be greater than 20 times the refractive index of the first lens. Preferably, Equation 23 can satisfy: 24 <CA11 / Nd1<35。

[0221] [Equation 24] 1 <CG_Max / CG4<5

[0222] CG_Max refers to the maximum center distance between lenses in the optical system. If Equation 24 is satisfied, the maximum center distance between lenses is set on the object side, rather than between the fourth and fifth lenses, and the increase in the size of the fifth lens can be suppressed. Preferably, the following equation can be satisfied: 2 <CG_Max / CG4<4。

[0223] [Equation 25] 0.5 <CT5 / BFL<2

[0224] In Equation 25, when the center thickness of the fifth lens and the optical axis distance (BFL) between the fifth lens and the sensing unit 151 are satisfied, the incident light can be transmitted through the fifth lens to the entire area of ​​the sensing unit 151. Preferably, the following equation can be satisfied: 0.7 <CT5 / BFL<1.5。

[0225] [Equation 26] 3 <TTL / Max_CG<9

[0226] In Equation 26, the total optical axis length (TTL) can be set to be greater than three times the maximum distance Max_CG among the center distances between lenses. Therefore, the maximum center distance can be set within the total optical axis length. Preferably, Equation 26 satisfies: 4 <TTL / Max_CG<7.5。

[0227] [Equation 27] 5 <TTL / Max_CT<12

[0228] In Equation 27, the total optical axis length (TTL) can be set to be greater than 5 times the maximum thickness Max_CT within the center thickness of the lens. Therefore, the maximum center thickness of the lens can be set within the total optical axis length. Preferably, Equation 27 satisfies: 6 <TTL / Max_CT<11。

[0229] [Equation 28] 5<|L5R2| / CT5

[0230] L5R2 is the radius of curvature of the sensor-side surface of the fifth lens. When equation 28 is satisfied, the refractive power of the fifth lenses 105 and 115 can be controlled, and the optical performance can be improved. Preferably, the following equation can be satisfied: 7<|L5R2| / CT5<20 (first embodiment) or 100<|L5R2| / CT5 (second embodiment).

[0231] [Equation 29] 3<|L5R2| / L5R1

[0232] If Equation 29 is satisfied, the refractive power of the fifth lenses 105 and 115 can be controlled, and the optical performance can be improved.

[0233] [Equation 30] 10 <L1R1 / L1R2<70

[0234] 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 equation 30 is satisfied, the refractive power of the first lenses 101 and 111 can be controlled, and the optical performance can be improved. Preferably, equation 20 can be satisfied. <L1R1 / L1R2<50。

[0235] [Equation 31] 0 < |L2R1 / L2R2| < 2

[0236] L2R1 is the radius of curvature of the object-side surface of the second lens, and L2R2 is the radius of curvature of the sensor-side surface of the second lens. When Equation 31 is satisfied, the refractive power of the second lenses 102 and 112 can be controlled to improve optical performance, and the effective diameter of the sensor-side lenses of the second lenses 102 and 112 can be adjusted. Preferably, Equation 31 can satisfy: 1 ​​< |L2R1 / L2R2| < 1.5 (first embodiment) or 0 < |L2R1 / L2R2| < 1 (second embodiment).

[0237] [Equation 32] 0 <CT_Max / CG_Max<2

[0238] In Equation 32, the maximum center thickness CT_Max within the lens and the maximum center distance CG_Max between adjacent lenses can be set. If Equation 32 is satisfied, the optical system can have good optical performance at the focal length of the set field of view and can reduce TTL. Preferably, Equation 32 can satisfy: 0.4 <CT_Max / CG_Max<1。

[0239] [Equation 33] 0 < ΣCT / ΣCG < 2

[0240] ΣCT is the sum of the center thicknesses of the lenses, and ΣCG is the sum of the distances between adjacent lenses. If Equation 33 is satisfied, the optical system can have good optical performance at the focal length of the set field of view and can reduce TTL. Here, the first embodiment can satisfy: ΣCT>ΣCG, and the second embodiment can satisfy: ΣCT<ΣCG.

[0241] [Equation 34] 5<ΣNd<15

[0242] ΣNd refers to the sum of the refractive indices of each of the multiple lenses at the d-line. If Equation 34 is satisfied, the TTL can be controlled in the optical system 100, which mixes aspherical and spherical lenses, and improved resolution can be achieved. Furthermore, if the number of spherical lenses is greater than the number of aspherical lenses, the sum of the TTL and refractive indices can be set. Equation 34 preferably satisfies: 7 < ΣNd < 10.

[0243] [Equation 35] 10<ΣVd / ΣNd<50

[0244] ΣVd refers to the sum of the Abbe numbers of each of the multiple lenses. If Equation 35 is satisfied, the optical system 100 can have improved aberration characteristics and resolution. By setting the sum of the Abbe numbers of the lenses and the sum of their refractive indices in Equation 35, the optical characteristics can be controlled, and the following equation can preferably be satisfied: 15 < ΣVd / ΣNd < 25.

[0245] [Equation 36] 200<ΣCT n<450

[0246] ΣCT is the sum of the center thicknesses of the multiple lenses, and n is the number of lenses in the optical system. If Equation 36 is satisfied, then TTL can be controlled. Preferably, 200 < ΣCT can be satisfied. n<350.

[0247] [Equation 37] 1 <CA11 / CA_Min<3

[0248] CA_Min refers to the minimum effective diameter between the object-side surface of the lens and the sensor-side surface. If Equation 37 is satisfied, the optical system can control the incident light and maintain optical performance. Equation 38 preferably satisfies: 1 <CA11 / CA_Min<3。

[0249] [Equation 38] 1 <CA_Max / CG_Max<4

[0250] CA_Max refers to the maximum effective diameter within the lens surface, and CG_Max refers to the maximum center distance within the lens. If Equation 38 is satisfied, the maximum center distance is arranged within the above range based on the maximum effective diameter, thereby reducing TTL. Preferably, the following equation can be satisfied: 1.5 <CA_Max / CG_Max<3.5。

[0251] [Equation 39] 0.5 <CA_Max / D2<1.5

[0252] If equation 39 is satisfied, the position of the optical filter 155 can be set based on the separation distance from the first lenses 101 and 111 and the maximum effective diameter of the lens surface. Preferably, the following equation can be satisfied: 0.5 <CA_Max / D2<1。

[0253] [Equation 40] 1 <TTL / D1<3

[0254] In Equation 40, the total optical axis length (TTL) of the optical system can be set to be less than 3 times the optical axis distance D1 between the optical filter 155 and the sensing unit, so that the position of the optical filter 155 can be set.

[0255] [Equation 41] 1 <CA_Max / (2 ImgH) <5

[0256] In Equation 42, the maximum effective diameter CA_Max of the lens surface can be set to the diagonal length of the sensing unit 151 (2 ImgH), and if this is satisfied, the optical system can be configured with a sensor device capable of maintaining good optical performance. Equation 41 can preferably satisfy: 2 <CA_Max / (2 ImgH) < 4.

[0257] [Equation 42] 1 <TD / CA_Max<4

[0258] 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 Equation 42 is satisfied, the total optical axis distance TD and the maximum effective diameter of the lens can be set, allowing for dimensions suitable for good optical performance. Equation 42 preferably satisfies: 1 <TD / CA_Max<3。

[0259] [Formula 42-1] SD <TD

[0260] SD is the optical axis distance from the position of the aperture to the surface of the sensing element.

[0261] [Equation 43] 0 <F / │L5R2│<0.5

[0262] F is the effective focal length of the optical system, and L5R2 is the radius of curvature of the sensor-side surface of the fifth lens. If Equation 43 is satisfied, the effect on the reduction of the optical system, such as TTL, can be controlled by setting the effective focal length and the radius of curvature of the sensor-side surface of the last aspherical lens. Equation 43 can preferably satisfy: 0 <F / │L5R2│<0.2。

[0263] [Equation 44] 0 <F / L1R1<0.5

[0264] In Equation 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 effects on the incident light and TTL. Preferably, Equation 44 can satisfy: 0 <F / L1R1<0.2。

[0265] [Equation 45] 0 <EPD / │L5R2│<0.5

[0266] EPD refers to the entrance pupil diameter of the optical system 100. When the optical system 100 according to the embodiment satisfies Equation 45, the optical system 100 is able to control the incident light. Preferably, the following condition can be satisfied: 0 <EPD / L5R2<0.2。

[0267] [Equation 46] 0 <EPD / L1R1<0.5

[0268] In Equation 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 when these conditions are met, the optical system 100 can control the incident light. Preferably, the following condition can be satisfied: 0 <EPD / L1R1<0.2。

[0269] [Equation 47] 1<|F1│ / F<5

[0270] F1 is the focal length of the first lens, and F is the total focal length. When Equation 47 is satisfied, for an optical system with a field of view of 110 degrees or greater, the focal power of the first lens can be set to negative.

[0271] [Equation 48] 1<|F2│ / F<10

[0272] F2 is the focal length of the second lens. If Equation 48 is satisfied, then for an optical system with a field of view of 110 degrees or greater, the focal power of the second lens can be set to negative.

[0273] [Equation 48-1] 1 <F3 / F<10

[0274] [Equation 48-2] 1 <F4 / F<10

[0275] [Equation 48-3] 1 <F5 / F<6

[0276] In Equation 48-1, the optical filter and the angle of incidence (AOI) of the lens with a small F-number can be configured. In Equation 48-2, the characteristics of the lens with a small F-number can be configured so that the fourth lenses 104 and 114 after the aperture stop can have positive refractive power. Furthermore, Equation 48-2 allows for the configuration of the optical filter and the angle of incidence (AOI) of the lens with a small F-number. In Equation 48-3, the characteristics of the lens with a small F-number can be configured so that the last lenses 105 and 115 adjacent to the sensing unit 151 have positive refractive power.

[0277] [Equation 49] 0<|F1 / F5|<5

[0278] In Equation 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, the following equation satisfies: 0 < |F1 / F5| < 1.

[0279] [Form 49-1] | F1 | <F4

[0280] [Equation 49-2] F3 <F4

[0281] [Formula 49-3] F5 <F4

[0282] In Formulas 49-1 to 49-3, F1, F2, F3, F4, and F5 are the focal lengths of the first lens to the fifth lens. By adjusting the focal length of the spherical lens to the focal length of the last aspherical lens, light can be guided to the effective area of the aspherical lens. The balance of each focal length of each lens can suppress the difference in point positions caused by temperature changes. Therefore, the optical characteristics of the imaging lens can be suppressed from being deteriorated due to temperature changes.

[0283] [Formula 50] 0 < F3 / F4 < 2

[0284] The third lens and the fourth lens are provided as spherical lenses with positive refractive power, which can improve aberration and can effectively guide light using an aspherical lens.

[0285] [Formula 51] 80 mm < TTL < 200 mm

[0286] TTL (Total Track Length) means the distance on the optical axis OA from the center of the first surface S1 of the first lenses 101 and 111 to the image surface of the sensing unit 151. If Formula 51 is satisfied, it can be applied to a vehicle optical system with TTL. Formula 51 can preferably be satisfied: 100 mm < TTL < 150 mm.

[0287] [Formula 52] 5 mm < ImgH < 20 mm

[0288] Formula 52 can set 1 / 2 of the diagonal length of the sensing unit 151 and provide an optical system with the size of a vehicle sensor. Formula 52 can preferably be satisfied: 7 mm < ImgH < 15 mm.

[0289] [Formula 53] 5 mm < BFL < 20 mm

[0290] In Formula 53, BFL (Back Focal Length) is set to be more than 5 mm, thereby ensuring the installation space of the cover glass 153, improving the assembly of components through the gap between the sensing unit 151 and the last lens, and improving the bonding reliability. Formula 53 is preferably satisfied: 8 mm < BFL < 18 mm. When BFL is less than the range of Formula 53, some light traveling to the sensing unit cannot be transmitted to the sensing unit, which may cause a reduction in resolution. When BFL exceeds the range of Formula 53, stray light may be introduced, which may deteriorate the aberration characteristics of the optical system.

[0291] [Formula 54] 5 mm < F < 20 mm

[0292] Formula 54 can set the total focal length F to suit a vehicle optical system. Formula 54 can be satisfied: 5 mm < F < 15 mm.

[0293] [Formula 55] 100 degrees < FOV

[0294] In Equation 55, FOV (field of view) refers to the viewing angle (degrees) of optical system 100, and a vehicle optical system with an FOV exceeding 100 degrees can be provided. Preferably, Equation 55 can satisfy: 110 ≤ FOV ≤ 150.

[0295] In Equation 55, the range of the vehicle optical system can be set by the field of view (FOV). The sensor length in the horizontal direction is based on 18 mm ± 0.7 mm. Furthermore, when Equation 55 is satisfied, the rate of change of the effective focal length and the rate of change of the FOV when the temperature changes from room temperature to high temperature can be set to 5% or less, for example, 0% to 5%. Additionally, even if two or more aspherical lenses are mixed with spherical lenses and used in the optical system 100, temperature compensation and aberration correction can be performed using aspherical lenses made of glass to prevent degradation of optical properties.

[0296] [Equation 56] 1 <TTL / Vd1<7

[0297] Equation 56 establishes the relationship between the entire optical axis length of the optical system and the Abbe numbers of the first lenses 101 and 111, thereby providing an improved vehicle optical system. Preferably, Equation 56 can satisfy 2 <TTL / Vd1<5。

[0298] [Equation 57] 10 <TTL / ImgH<30

[0299] Equation 57 allows setting the total optical axis length (TTL) of the optical system and the diagonal length (ImgH) of the optical axis from the sensing unit 151. When the optical system 100 according to the embodiment satisfies Equation 57, the optical system 100 can have a TTL for application with the vehicle sensing unit 151, thereby providing further improved image quality. Equation 57 can preferably satisfy: 10 <TTL / ImgH<20。

[0300] [Equation 58] 1 <BFL / ImgH<3

[0301] Equation 58 allows setting the optical axis distance between the sensing unit 151 and the final lens, as well as the length diagonally from the optical axis of the sensing unit 151. When the optical system 100 according to the embodiment satisfies Equation 58, the optical system 100 can ensure the BFL (Browser-to-Flight) for the application of the size of the vehicle sensing unit 151, set the gap between the final lens and the sensing unit 151, and have good optical characteristics in the center and periphery of the FOV. Equation 58 preferably satisfies: 1 <BFL / ImgH<2。

[0302] [Formula 58-1] ImgH <BFL<D1

[0303] The BFL can be greater than a value (ImgH) that is 1 / 2 of the diagonal length of the sensing unit 151 and less than the optical axis distance D1 from the optical filter 155 to the surface of the sensing unit 151. Additionally, the following condition can be satisfied: ImgH < BFL < ImgH 2.

[0304] [Equation 59] 6 < TTL / BFL < 15

[0305] Equation 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 last lens. When the optical system 100 according to the embodiment satisfies Equation 59, the optical system 100 can ensure the BFL. Equation 59 is preferably satisfied: 7 < TTL / BFL < 12.

[0306] [Equation 60] 0 < F / TTL < 0.5

[0307] Equation 60 can set the total focal length (F) and the total optical axis length (TTL) of the optical system 100. Therefore, an optical system for a driver assistance system can be provided. Equation 60 can be satisfied: 0 < TTL / F < 0.2. When the optical system 100 according to the embodiment satisfies Equation 60, the optical system 100 can have an appropriate focal length and a wide viewing field within the set TTL range, and provide an optical system that can maintain an appropriate focal length and form an image even when the temperature changes from low to high. When it is less than the lower limit of Equation 60, it is necessary to increase the refractive power of the lens, making it difficult to correct spherical aberration or distortion aberration, and when it exceeds the upper limit of Equation 60, the effective diameter or TTL of the lens will become longer, which can cause the problem of the imaging lens system becoming larger.

[0308] [Equation 61] 0 < F / BFL < 2

[0309] Equation 61 can set the total focal length (F) of the optical system 100 and the optical axis distance BFL between the sensing unit 151 and the last lens. When the optical system 100 according to the embodiment satisfies Equation 61, the optical system 100 can have a set viewing angle and an appropriate focal length, and can provide a vehicle optical system. Additionally, the optical system 100 can minimize the gap between the last lens and the sensing unit 151, such that it can have good optical characteristics in the periphery of the FOV. Equation 61 can preferably be satisfied: 0.4 < F / BFL < 1.

[0310] [Equation 62] 0.5 < F / ImgH < 1.5

[0311] Equation 62 can set the total focal length (F) of the optical system 100 and the diagonal length (ImgH) starting from the optical axis of the sensing unit 151. This optical system 100 can have aberration characteristics improved in terms of the size of the vehicle sensing unit 151. Equation 62 preferably satisfies: 0.8 < F / ImgH < 1.4 or 1 < F / ImgH < 1.4.

[0312] [Equation 63] 0.5 < F / EPD < 1.5

[0313] Equation 63 can set the total focal length (F) and the entrance pupil diameter of the optical system 100. Therefore, this optical system has a small F-number, enabling control of the overall brightness. Equation 63 preferably satisfies: 0.5 < F / EPD < 1.

[0314] [Equation 64] 100 < TTL / F# < 250

[0315] Equation 64 can set the F-number (F#) and the entire optical axis length. Therefore, the overall size and brightness of the optical system can be controlled. Equation 64 preferably satisfies: 120 < TTL / F# < 220.

[0316] [Equation 65] 100 < FOV / F# < 250

[0317] Equation 65 can set the relationship between the FOV of the optical system and the F-number F#. Equation 65 can satisfy: 120 < FOV / F# < 220. Here, F# is provided as 1.2 or less or 1 or less, enabling a bright image to be provided.

[0318] [Equation 66] 120 < (CT_Max + CG_Max) n < 250

[0319] Preferably, Equation 66 can set the maximum value of the central thickness of each lens, the maximum value of the central distance between adjacent lenses, and the number of lenses (n), and can satisfy the condition: 150 < (CT_Max + CG_Max) n < 230.

[0320] [Equation 67] 15 < TTL / n < 40

[0321] Preferably, Equation 67 can set the number of lenses (n) according to the total optical axis length, and can satisfy the condition: 20 < TTL / n < 30.

[0322] [Equation 68] 0.5 < FOV < TTL < 1.5

[0323] In Equation 68, if the FOV and total optical axis length (TTL) of the optical system are satisfied, the optical axis length of an optical system with an FOV of 110 degrees or greater can be set. Therefore, the chromatic aberration, resolution, size, etc., of an optical system with 6 or fewer lenses can be controlled.

[0324] [Formula 69]

[0325] In Equation 69, Z can refer to sag, the distance from any position on the aspherical surface to the vertex of the aspherical surface along the optical axis. Y can refer to the distance from any position on the aspherical surface to the optical axis in a direction perpendicular to the optical axis. c can refer to the curvature of the lens, and K can refer to the conic constant. Additionally, A, B, C, D, E, and F can refer to aspherical coefficients.

[0326] The optical system 100 according to this embodiment can satisfy at least one or two or more of Equations 1 to 68. In this case, the optical system 100 can have improved optical characteristics. Specifically, when the optical system 100 satisfies at least one of Equations 1 to 34 and / or at least one of Equations 35 to 68, the optical system 100 has improved resolution and is able to improve aberration and distortion characteristics. In addition, the optical system 100 can ensure that the BFL used for the vehicle sensing unit 151 can compensate for the degradation of optical characteristics caused by temperature changes and can minimize the gap between the final lens and the sensing unit 151, thereby having good optical performance at the center and periphery of the FOV.

[0327] Table 1 shows the items of the above formula in the optical system 100 of the embodiment, including the TTL (mm), BFL (mm), effective focal length F, ImH (mm), effective diameter (mm), sum of center thickness of each lens, sum of center distance between adjacent lenses, sum of Abbe number, sum of refractive index, optical axis distance TD (mm) from the first surface S1 to the tenth surface S10, focal length F1, F2, F3, F4 and F5 of each of the first to fifth lenses, compound focal length, FOV, edge thickness ET, F number, etc.

[0328] [Table 1]

[0329] Table 2 shows the result values ​​of Equations 1 to 34 above in the optical system 100 of the embodiment. Referring to Table 2, it can be seen that the optical system 100 satisfies at least one, two or more, or three or more of Equations 1 to 34. Therefore, the optical system 100 is able to have good optical performance and excellent optical characteristics at the center and periphery of the FOV.

[0330] [Table 2]

[0331] Table 3 shows the result values ​​of Equations 35 to 68 above in the optical system 100 of the 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 Equations 35 to 68. Therefore, the optical system 100 is able to have good optical performance and excellent optical characteristics at the center and periphery of the FOV.

[0332] [Table 3]

[0333] Figure 11 This is a block diagram of a sensor device with a receiving optical system according to an embodiment of the present invention. (Reference) Figure 11 The sensor device includes a control unit 10, a light source driving unit 20, a transmitting optical system 30, a receiving optical system 50 disclosed above, and a signal processing unit 60.

[0334] The control unit 10 controls the transmission and reception of signals and can be linked to devices related to communication services such as autonomous driving modules, artificial intelligence modules, drones, robots, augmented reality devices, virtual reality devices, and 5G and 6G 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. This 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 can include terrain information of the driving section, traffic congestion information, weather, etc. The wavelength of the laser beam generated from the light source can be in the range of 890nm to 960nm or in the range of 940nm ± 10nm. As another example, the wavelength of the laser beam can be 1550nm ± 10nm. The laser light 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.

[0335] The transmitting optical system 30 transmits a laser beam generated by a light source to the object 40 through a lens section and a diffuser, and receives the light reflected from the object 40 through the receiving optical system 50. The receiving optical system 50 may consist of multiple optical sensors, and the optical sensors use photodiodes to convert the received light into electrical signals. That is, the sensing units are arranged in a matrix type to convert the light received from the object, scanned in each of the horizontal and vertical directions, into an electric current. The signal processing unit 60 converts the output of the receiving optical system 50 into a voltage, amplifies it, and then uses an analog-to-digital converter to convert the amplified signal into a digital signal. The signal processing unit 60 uses a TOF (Time-of-Flight) algorithm or a phase-shifting algorithm to analyze the digital data to detect the distance and shape of the object 40.

[0336] The control unit 10 can receive vehicle speed information and road condition information via a control unit (e.g., an ECU) or a network. The control unit 10 can also receive driving environment information via a network. This driving environment information may include terrain information of the driving segment, traffic congestion information, weather, etc. The control unit 10 can adjust gain based on one or more of the vehicle speed, road surface conditions of the road on which the vehicle is traveling, and driving environment information, and can provide the autonomous driving device with sensor data including distance to and shape information of objects.

[0337] Figure 12 This is a diagram illustrating a transmitting optical system according to an embodiment of the present invention.

[0338] refer to Figure 12 The transmitting optical system 100A can include a sixth to a ninth lens 121, 122, 123, and 124 arranged sequentially from the object side toward the light source 129, and a diffuser 120. The sixth to ninth lenses 121, 122, 123, and 124 illuminate the subject and have... Figure 1 and Figure 6 The receiving optical system 100, consisting of the first to fifth lenses, is capable of receiving light reflected from the subject. For example, the number of lenses in the transmitting optical system can differ from the number of lenses in the receiving optical system. The number of lenses in the transmitting optical system can be five or fewer, for example, in the range of three to five.

[0339] The diffuser 120 is positioned closest to the object being photographed and may include microlens arrays on at least one or both of its incident and exit surfaces. An aperture stop for the transmitting optical system may be arranged around the periphery of the light source-side surface of the diffuser 120. The aperture stop for the transmitting optical system may be arranged at a position spaced apart from the sixth lens 121 in the object direction. The aperture stop on the transmission side can suppress an increase in the effective diameter of the sixth lens 121. The aperture stop of the transmitting optical system 100A may be removed.

[0340] The sixth lens 121 may have positive (+) or negative (-) refractive power on the optical axis OA. The sixth lens 121 may have positive (+) refractive power. The sixth lens 121 may comprise a plastic material or a glass material, and may be, for example, a glass material. A sixth lens 121 made of glass material can reduce changes in center position and radius of curvature caused by temperature variations in the surrounding environment, and can protect the output-side surface of the transmitting optical system 100A. The object-side surface of the sixth lens 121 may be convex on the optical axis, and the light-source-side surface may be concave. Both the object-side and light-source-side surfaces of the sixth lens 121 may have spherical surfaces. The sixth lens 121 may have a meniscus shape convex toward the object side.

[0341] A seventh lens 122 can be disposed between the sixth lens 121 and the eighth lens 123. The seventh lens 122 can have positive (+) or negative (-) refractive power in the direction of the optical axis OA. The seventh lens 122 can have negative (-) refractive power. The seventh lens 122 can comprise plastic or glass material, and can be provided as, for example, glass material. The object-side surface of the seventh lens 122 can be convex relative to the optical axis OA, and the sensor-side surface can be concave. Both the object-side surface and the light source-side surface can be spherical. The center distance between the seventh lens 122 and the eighth lens 123 can be the largest among the center distances of the lenses in the transmitting optical system.

[0342] The eighth lens 123 may have positive (+) or negative (-) refractive power along the optical axis OA. The eighth lens 123 may have negative (-) refractive power. The eighth lens 123 may comprise plastic or glass material, and may be provided as, for example, glass material. The object-side surface of the eighth lens 123 may be convex along the optical axis, and the light source-side surface may be concave. The eighth lens 123 may have a shape that convexes from the optical axis OA toward the object. At least one or both of the object-side surface and the light source-side surface of the eighth lens 123 may be spherical. The ninth lens 124 may have positive (+) or negative (-) refractive power relative to the optical axis OA.

[0343] The ninth lens 124 may have a positive (+) refractive power. The ninth lens 124 may comprise plastic or glass material, and may be injection molded using glass material. The object-side surface of the ninth lens 124 may be convex relative to the optical axis, and the light source-side surface may also be convex. The ninth lens 124 may have a convex shape on both sides. The object-side and light source-side surfaces of the ninth lens 124 may be aspherical. The effective diameter of the ninth lens 124 may be smaller than the effective diameters of the sixth lens 121 and the seventh lens 122. The eighth lens 123 may have a refractive index higher than that of the sixth lens 121 and the seventh lens 122.

[0344] The ninth lens 124 can be the aspherical lens closest to the light source 129. Two or fewer aspherical lenses can be arranged adjacent to the light source 129. The light source 129 generates a laser beam of wavelength that can be in the range of 800 nm to 1000 nm, preferably in the range of 890 nm to 960 nm or 940 nm ± 10 nm. The light source 129 can be implemented as an InGaAs / GaAs-based semiconductor diode laser and can emit a high-power laser beam. The light source 129 can include a single emitter and / or multiple emitters. The light source 129 generates a laser beam in the form of a line source or a point source.

[0345] Figure 13 This is a diagram illustrating an example of measuring an object in a vehicle equipped with the sensor system of the present invention, and Figure 14 This is a diagram illustrating an example of ambient monitoring in a vehicle equipped with the sensor system of the present invention.

[0346] refer to Figure 13 and Figure 14 The vehicle 202, equipped with a sensor system, includes a transmitting optics system that projects a laser beam 201 generated by a light source toward a target scene; and a receiving optics system that receives light 203 reflected from the target or subject 210. Additionally, the sensor system includes a LiDAR system, which typically includes a controller that calculates distance information to the subject 210 based on the reflected light, and means for scanning or providing a specific pattern of light, which can be a static pattern within the desired range and field of view (FOV). The transmitting and receiving optics systems are used to convert the received signal light into measurements representing a point-by-point three-dimensional map of the surrounding environment within the range and FOV of the LiDAR system.

[0347] 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, a target plane associated with a specific distance is illuminated in the scene, and known information about the beam profile, based on the specific design of the light source and projection system, is used to determine the positional information of reflecting surfaces, thereby generating a complete x, y, z, or 3D picture of the scene. In other words, a point-by-point 3D map of the surrounding environment represents the set of measurement data from all surfaces within the LiDAR system's field of view that reflect light from the light source to the receiver, providing positional information. In this way, a 3D representation of objects within the LiDAR system's field of view is obtained.

[0348] The illustration also shows a schematic diagram illustrating the 2D field of view and ranging requirements of a typical LIDAR system 200 for sensing the surrounding environment of a vehicle 202. For example, adaptive cruise control functions may require a field of view and ranging 204 with a narrower field of view and ranging 204 than the "surround view" field of view and ranging 206, but with a longer field of view and ranging requirements. Typically, the sensor performance of a motor vehicle can be achieved through a combination of LIDAR, radar, cameras, and ultrasonic sensors. The combination of these sensor data to generate information about the surrounding environment is often referred to as "sensor fusion." While the present invention describes LIDAR systems in the context of motor vehicles, where LIDAR is widely used in autonomous or self-driving 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.

[0349] 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 relative to other embodiments. Therefore, anything related to these combinations and variations should be interpreted as being included within the scope of the present invention. Although described based on embodiments, these are merely examples, and the present 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 basic characteristics of this embodiment. For example, each component specifically shown in the embodiments can be modified and implemented. And the differences associated with these modifications and applications should be interpreted as being included within the scope of the present invention as defined in the appended claims.

Claims

1. An optical system, comprising: The first lens is the closest to the object; The final lens is adjacent to the sensing unit. Multiple lenses are disposed between the first lens and the last lens and are aligned with the optical axis; as well as An optical filter is disposed in one of the regions between the plurality of lenses. Wherein, the center distance between two lenses adjacent to the object side of the optical filter is greater than the center distance between two lenses adjacent to the sensor side of the optical filter. Wherein, the optical axis distance from the object-side surface of the first lens to the surface of the sensing unit is TTL. Wherein, half of the diagonal length of the sensing unit is ImgH, and Wherein, the following formula satisfies: 10 <TTL / ImgH<30。 2. The optical system according to claim 1, in, The optical axis distance from the sensor-side surface of the optical filter to the surface of the sensing unit is D1. Wherein, the optical axis distance from the sensor-side surface of the last lens to the surface of the sensing unit is BFL, and Wherein, the following equation satisfies: 2 <D1 / BFL<6。 3. The optical system according to claim 1, in, The optical axis distance from the sensor-side surface of the optical filter to the surface of the sensing unit is D1. Wherein, the optical axis distance from the object-side surface of the optical filter to the object-side surface of the first lens is D2, and Wherein, the following equation satisfies: D1 <D2。 4. The optical system according to any one of claims 1 to 3, comprising: A second lens and a third lens are arranged sequentially on the optical filter, starting with the first lens. The center distance between the second lens and the third lens is greater than the center distance between the first lens and the second lens.

5. The optical system according to claim 4, comprising: A fourth lens is disposed between the optical filter and the final lens. The center distance between the third lens and the fourth lens is less than the center distance between the second lens and the third lens.

6. The optical system according to any one of claims 1 to 3, in, At least two of the lenses in the optical system are aspherical lenses on the optical axis, and The lens in the optical system is made of glass.

7. The optical system according to any one of claims 1 to 3, in, The optical filter has a transmittance of 90% or greater for some wavelengths in the range of 800 nm to 1000 nm, and The optical filter is configured to be closer to the object side of the optical system than the lens located on the sensor side of the optical filter.

8. The optical system according to any one of claims 1 to 3, in, The object-side lens and the sensor-side lens, which are disposed on both sides of the optical filter, have a spherical shape on the optical axis.

9. The optical system according to claim 8, in, The lens between the lens adjacent to the object side of the optical filter and the first lens is an aspherical lens made of glass.

10. The optical system according to claim 9, wherein, The final lens is an aspherical lens made of glass.

11. The optical system according to any one of claims 1 to 3, in, The first lens has negative refractive power and a meniscus shape convex toward the object, and The final lens has positive refractive power and a biconvex shape.

12. The optical system according to any one of claims 1 to 3, in, The F number is 1 or less.

13. A receiving optical system, comprising: The first lens to the fifth lens are aligned along the optical axis from the object toward the sensing unit; as well as An optical filter, spaced apart from the sensing unit and disposed between the third lens and the fourth lens, is provided. The first lens has negative refractive power. Of these, at least two of the third to fifth lenses have positive refractive power. Wherein, at least one lens between the first lens and the optical filter has an aspherical shape on both the object-side surface and the sensor-side surface. The fifth lens has an aspherical shape on its optical axis. The optical axis distance between the second lens and the third lens is the largest among the optical axis distances between adjacent lenses from the first lens to the fifth lens.

14. The receiving optical system according to claim 13, in, The optical filter includes a bandpass filter. Wherein, the optical axis distance from the optical filter to the surface of the sensing unit is D1. The center thickness of the fifth lens is CT5, and Wherein, the following formula satisfies: (CT5) 3) <D1<(CT5 5).

15. The receiving optical system according to claim 13 or 14, in, The first lens includes a convex object-side surface and a recessed sensor-side surface along the optical axis. The second lens includes a recessed object-side surface and a recessed sensor-side surface along the optical axis. The first to fifth lenses are made of glass. Among them, the first lens, the third lens and the fourth lens are lenses whose object side and sensor side are spherical.

Images