Receiving optical system, transmitting optical system, sensor system and LiDAR device

Abstract

The receiving optical system disclosed in the embodiment of the invention includes a first lens closest to the object side, an nth lens (n is 6 or less) closest to the image sensor, a plurality of lenses arranged between the first lens and the nth lens and aligned with the optical axis, and an optical filter arranged in any one of the regions between the plurality of lenses. The optical axis distance from the optical filter to the surface of the image sensor is D1, and the optical axis distance from the sensor side surface of the nth lens closest to the image sensor to the surface of the image sensor is BFL, and the formula: BFL < D1 can be satisfied.

Description

[Technical Field]

[0001] The embodiments relate to a receiving optical system and a sensor system having the same. The embodiments relate to a transmitting optical system and a sensor system having the same. The embodiments relate to a receiving optical system for LiDAR (Light detection and ranging), a transmitting optical system, and a device having the same. The embodiments of the invention relate to a mobile object having a LiDAR receiving optical system, a transmitting optical system, and a system. [Background technology]

[0002] ADAS (Advanced Driving Assistance System) is an advanced driving assistance system that assists drivers in driving. It senses the situation ahead, determines the situation based on the sensing results, and controls the vehicle's movement based on the situation determination. For example, an ADAS sensor device detects vehicles ahead and recognizes lanes. After that, once the target lane, target speed, and forward targets are determined, the vehicle's Electrical Stability Control (ESC), Engine Management System (EMS), Motor Driven Power Steering (MDPS), etc. are controlled. Typically, ADAS can be implemented in automatic parking systems, low-speed city driving assistance systems, blind spot warning systems, etc.

[0003] With the recent rise in interest in autonomous vehicles, demand for LiDAR (Light Detection and Ranging) sensors, a key component of autonomous vehicles, is on the rise. Currently, LiDAR is only used in high-spec, expensive vehicles, but due to reduced manufacturing costs, it is expected to be adopted in general vehicles as well. Ultra-compact and lightweight LiDAR technology can be used not only as a sensor for unmanned vehicles, but also in satellites and aerospace for Earth topography and environmental observation, unmanned vehicles, transporters, cranes, and robots used in factories and shipyards. With the integration of land, aviation, and marine industries, combined or cooperative operation between mobile devices is expected to emerge. Therefore, the development of an optical system for ultra-compact and lightweight LiDAR to realize ultra-compact and lightweight LiDAR is becoming increasingly urgent. Summary of the Invention [Problem to be solved by the invention]

[0004] The embodiments provide a receiving optical system with improved optical characteristics and a sensor system having the same. The embodiments provide a wide-angle receiving optical system and a sensor system having the same. The embodiments provide a receiving optical system, a sensor system, and a LiDAR device with improved thermal compensation characteristics.

[0005] The embodiments provide a transmission optical system with improved optical properties and a sensor system having the same. The embodiments provide a wide-angle transmission optical system and a sensor system having the same. The embodiments provide a transmission optical system, a sensor system, and a LiDAR device with improved thermal compensation properties. [Means for solving the problem]

[0006] The receiving optical system according to an embodiment of the invention includes a first lens closest to the object, an nth lens (n is 6 or less) closest to the image sensor, a plurality of lenses arranged between the first lens and the nth lens and aligned with the optical axis, and an optical filter arranged in any one of the regions between the plurality of lenses. The optical axis distance from the optical filter to the surface of the image sensor is D1, and the optical axis distance from the sensor side surface of the nth lens closest to the image sensor to the surface of the image sensor is BFL, and the formula: BFL < D1 can be satisfied.

[0007] According to an embodiment of the invention, it includes an aperture arranged between the lens arranged on the object side of the optical filter and the optical filter and arranged around the lens arranged on the object side of the optical filter. SD is the optical axis distance from the aperture to the surface of the image sensor, and the formula: 1 < SD / D1 < 1.2 can be satisfied.

[0008] According to an embodiment of the invention, CT n 0 is the central thickness of the nth lens, CTn-1 is the central thickness of the (n - 1)th lens arranged on the object side of the nth lens, TTL is the optical axis distance from the center of the object side surface of the first lens to the surface of the image sensor, and the formula: (CT n + CT n-1 ) < D1 < TTL / can be satisfied.

[0009] According to an embodiment of the invention, the optical filter may be a band-pass filter that passes through the range of 890 nm to 960 nm.

[0010] The first lens may have a convex object-side surface and a concave sensor-side surface on the optical axis. The second lens spaced from the first lens toward the sensor may have a flat object-side surface and a concave sensor-side surface. The third lens spaced from the optical filter toward the object may have both convex surfaces on the optical axis, and the fourth lens spaced from the optical filter toward the sensor may have both convex surfaces on the optical axis. The n-th lens may have a convex object-side surface and a convex sensor-side surface on the optical axis.

[0011] According to an embodiment of the invention, the first lens may have negative refractive power, the n-th lens may have positive refractive power, and the number of lenses having positive refractive power among the plurality of lenses may be greater than the number of lenses having negative refractive power among the plurality of lenses. The object-side surface of the first lens may have the largest effective diameter among the lenses in the optical system, and the sensor-side surface of a second lens disposed on a sensor side of the first lens may have the smallest effective diameter among the lenses in the optical system, the first lens may be a spherical lens, and the n-th lens may be a fifth lens and be an aspherical lens.

[0012] A transmitting optical system according to an embodiment of the invention may include a first lens closest to an object, an n-th lens (n ​​is 6 or less) closest to a light source, and a plurality of lenses arranged between the first lens and the n-th lens and aligned with an optical axis, wherein the first lens has a meniscus shape convex toward the object side, the n-th lens has convex surfaces on both sides at the optical axis, and an (n-1)-th lens located from the n-th lens to the object side has convex surfaces on both sides at the optical axis, the first lens may be made of glass, and the object-side surface and the light source-side surface on the optical axis may be spherical, and the n-th lens may be made of glass, and the object-side surface and the light source-side surface on the optical axis may be aspherical.

[0013] According to an embodiment of the invention, the second lens disposed on the light source side of the first lens may have a flat object side surface and a concave light source side surface on the optical axis.

[0014] According to an embodiment of the invention, a third lens arranged on the light source side of the second lens has convex surfaces on both sides at the optical axis, a fourth lens arranged on the light source side of the third lens has convex surfaces on both sides at the optical axis, the third lens has spherical surfaces on both sides at the optical axis, and the fourth lens has aspherical surfaces on both sides at the optical axis.

[0015] According to an embodiment of the invention, the first lens has negative refractive power, the n-th lens is a fifth lens and has positive refractive power, and the number of lenses with positive refractive power in the plurality of lenses may be greater than the number of lenses with negative refractive power.

[0016] A LiDAR device according to an embodiment of the invention includes a receiving optical system having an image sensor and first to fifth lenses aligned on a first optical axis from an object toward the image sensor; and a transmitting optical system having a light source and sixth to tenth lenses aligned on a second optical axis from the object toward the light source, wherein the first to fifth lenses include a spherical lens and an aspherical lens, and the sixth to tenth lenses include a spherical lens and an aspherical lens, and the receiving optical system includes an optical filter disposed between the spherical lens and the aspherical lens, wherein each of the first lens and the sixth lens has a meniscus shape that bulges toward the object side, the fifth lens has an object-side surface and a sensor-side surface that are convex and aspherical on the first optical axis, and the tenth lens has an object-side surface and a light source-side surface that are convex and aspherical on the second optical axis, the light source generates light in a range of 890 nm to 960 nm, and the optical filter is capable of transmitting light in the 890 nm to 960 nm range. [Effects of the Invention]

[0017] According to the embodiment, improved optical characteristics can be achieved. More specifically, in the receiving optical system according to the embodiment, the bandpass filter can be positioned close to the stop to minimize the angle of incidence of light entering the filter. This allows the transmittance range of the bandpass filter to be widely utilized according to the angle of incidence of light on the bandpass filter. The LiDAR receiving optical system of the invention can maximize the effect of receiving light emitted from the transmitting optical system.

[0018] The LiDAR receiving optical system of the present invention can have good optical performance in a low to high temperature range. More specifically, the multiple lenses included in the receiving optical system can have the same material, refractive power, and refractive index. As a result, when the refractive index of each lens changes due to a temperature change, and the focal length of each lens changes as a result, the glass molded lens and the glass lens can compensate for each other. That is, the receiving optical system can effectively allocate refractive power in a low to high temperature range, thereby preventing or minimizing changes in optical characteristics in a low to high temperature range. Therefore, the optical system and sensor system according to the embodiment can maintain improved optical characteristics in a variety of temperature ranges.

[0019] In the LiDAR receiving optical system of the present invention, the lenses can have a set thickness, refractive power, and spacing between adjacent lenses, which allows the optical system and sensor system according to the embodiment to have improved MTF characteristics, aberration control characteristics, resolution characteristics, etc. within a set field of view range, and to have good optical performance in the peripheral part of the field of view.

[0020] The receiving optical system and sensor system according to the embodiment can achieve a set field of view and excellent optical characteristics by combining a glass molded lens and a glass lens. As a result, the optical system can provide a slimmer vehicle sensor system. Therefore, the optical system and sensor system can be used in various applications and devices, and can have excellent optical characteristics even in harsh temperature environments, such as when exposed to the exterior of a vehicle or inside a vehicle in the summer heat.

[0021] The LiDAR transmission optical system of the present invention can maximize the extraction efficiency of light emitted from the transmission optical system. The LiDAR transmission optical system of the present invention can have good optical performance in a low to high temperature range. Specifically, multiple lenses included in the transmission optical system can have a predetermined material, refractive power, and refractive index. As a result, when the refractive index of each lens changes due to a temperature change and the focal length of each lens changes as a result, the glass molded lens and the glass lens can compensate for each other. In other words, the transmission optical system can effectively allocate refractive power in a low to high temperature range and prevent or minimize changes in optical characteristics in a low to high temperature range. Therefore, the optical system and sensor system according to the embodiments can maintain improved optical characteristics in various temperature ranges.

[0022] In the LiDAR transmission optical system of the present invention, lenses can have a set thickness, refractive power, and spacing between adjacent lenses. As a result, 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 range, and can have good optical performance at the periphery of the field of view. The transmission optical system and sensor system according to the embodiment can achieve excellent optical characteristics by combining a glass molded lens and a glass lens to satisfy a set field of view. As a result, the optical system can provide a slimmer sensor system for vehicles. Therefore, the optical system and sensor system can be used in a variety of applications and devices, and can have excellent optical characteristics even in harsh temperature environments, such as when exposed to the outside of a vehicle or inside a vehicle in the summer heat. [Brief explanation of the drawings]

[0023] [Figure 1] FIG. 2 is a side cross-sectional view of a receiving optical system of the LiDAR according to the embodiment.

[0024] [Figure 2] 2 is a table showing lens characteristics of the receiving optical system of FIG. 1.

[0025] [Figure 3] 2 is a table showing aspheric coefficients of lenses in the receiving optical system of FIG. 1.

[0026] [Figure 4] 2 is a table comparing the refractive index changes of each lens according to temperature in the receiving optical system of FIG. 1.

[0027] [Figure 5] 2 is a graph showing data on the diffraction MTF (Modulation Transfer Function) in response to low, normal, and high temperatures in the receiving optical system of FIG. 1.

[0028] [Figure 6]2 is a graph showing data on aberration characteristics of the receiving optical system of FIG. 1 at low temperatures.

[0029] [Figure 7] 2 is a graph showing data on aberration characteristics of the receiving optical system of FIG. 1 at room temperature.

[0030] [Figure 8] 2 is a graph showing data on aberration characteristics of the receiving optical system of FIG. 1 at high temperatures.

[0031] [Figure 9] 1 is a graph comparing transmittance curves measured by an automated optical inspection (AOI) device for filters according to embodiments of the present invention when the main beam incident angle is 0 degrees, 20 degrees, and 40 degrees.

[0032] [Figure 10] FIG. 2 is a side cross-sectional view of a transmission optical system of the LiDAR according to the embodiment.

[0033] [Figure 11] 11 is a table showing lens characteristics of the transmission optical system of FIG. 10.

[0034] [Figure 12] 11 is a table showing aspheric coefficients of lenses in the transmission optical system of FIG. 10.

[0035] [Figure 13] 11 is a table comparing the refractive index changes of each lens according to temperature in the transmission optical system of FIG. 10.

[0036] [Figure 14] 11 is a graph showing data on diffraction MTF in response to low, normal, and high temperatures in the transmission optical system of FIG. 10.

[0037] [Figure 15] 11 is a graph showing data on aberration characteristics at low temperatures of the transmission optical system of FIG. 10.

[0038] [Figure 16] 11 is a graph showing data on aberration characteristics of the transmission optical system of FIG. 10 at room temperature.

[0039] [Figure 17] 11 is a graph showing data on aberration characteristics at high temperatures of the transmission optical system of FIG. 10.

[0040] [Figure 18] FIG. 11 is a block diagram showing a sensor system having the transmission optical system of FIG. 10.

[0041] [Figure 19] 1 is a diagram showing an example of measuring an object using a vehicle having a sensor system of the invention.

[0042] [Figure 20] 1 is a diagram showing an example of periphery monitoring in a vehicle having a sensor system of the invention. DETAILED DESCRIPTION OF THE INVENTION

[0043] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The technical concept of the present invention is not limited to some of the described embodiments, but may be embodied in various forms, and one or more components between the embodiments may be selectively combined or substituted within the scope of the technical concept of the present invention. Furthermore, terms (including technical and scientific terms) used in the embodiments of the present invention should be interpreted as meanings that are commonly understood by those skilled in the art to which the present invention pertains, unless otherwise expressly specified. Commonly used terms, such as dictionary-defined terms, should be interpreted in light of the context of the relevant technology.

[0044] The terms used in the embodiments of the present invention are intended to describe the embodiments and are not intended to limit the present invention. In this specification, the singular can include the plural unless otherwise specified. For example, "A and (and) at least one (or more) of B and C" refers to one or more of all possible combinations of A, B, and C. Furthermore, when describing components of the embodiments of the present invention, terms such as "first," "second," "A," "B," (a), and (b) can be used. These terms are used to distinguish the component from other components and do not limit the nature or order of the components. Furthermore, when a component is described as being "coupled," "bonded," or "connected" to another component, it can refer not only to a case where the component is directly coupled or connected to the other component, but also to a case where the component is "coupled," "bonded," or "connected" to the other component via an additional component between the component and the other component. Furthermore, when a component is described as being formed or disposed "above or below" another component, "above or below" refers not only to a case where the two components are in direct contact with each other, but also to a case where one or more additional components are formed or disposed between the two components. Furthermore, when the expression "above or below" is used, it can mean not only an upward direction but also a downward direction based on one component.

[0045] In the description of the invention, the term "object-side surface" may refer to the surface of a lens facing the object side relative to the optical axis, and the term "sensor-side surface" may refer to the surface of a lens facing the imaging surface (image sensor) relative to the optical axis. A convex lens surface may refer to a convex shape on the optical axis or in the paraxial region, and a concave lens surface may refer to a concave shape in the optical axis or in the paraxial region. The radius of curvature, center thickness, and optical axis spacing between lenses listed in the lens data tables may refer to values ​​(unit: mm) on the optical axis. The vertical direction may refer to the direction perpendicular to the optical axis, and the end of a lens or lens surface may refer to the end of the effective area of ​​the lens through which incident light passes. The effective diameter of a lens surface may have a measurement error of up to ±0.4 mm depending on the measurement method. The paraxial region refers to a very narrow region near the optical axis, where the distance from the optical axis to light is approximately zero. Hereinafter, the meaning of the optical axis can include the center of each lens or a very narrow area near the optical axis.

[0046] FIG. 1 is a side cross-sectional view showing a receiving optical system according to an embodiment of the invention.

[0047] Referring to FIG. 1, a receiving optical system 100 and a sensor system including the same can be installed inside or outside a vehicle to monitor the driver or sense external objects or lanes. The lens material can be selected from glass or plastic, with glass having a smaller linear expansion coefficient than plastic. Glass lenses are used to prevent changes in focal position due to temperature changes. However, when an optical system is constructed using spherical glass lenses, there is a limit to how many lenses can be reduced, which in turn limits size and weight reduction. The receiving optical system 100 according to an embodiment of the invention can include spherical lenses and aspherical lenses. Here, the spherical lenses are lenses in which at least one or both of the object-side and sensor-side surfaces are spherical. The aspherical lenses are lenses in which at least one or both of the object-side and sensor-side surfaces are aspherical. The receiving optical system 100 can include spherical glass lenses and aspherical glass lenses. In addition, the aspherical lens reduces the overall length TTL of the optical system 100, and the aspherical lens can effectively correct various aberrations such as spherical aberration and chromatic aberration. In addition, the aspherical lens can minimize peripheral distortion.

[0048] The optical system 100 may include n lenses, where the nth lens may be the last lens adjacent to the image sensor 151 and the (n-1)th lens may be the lens closest to the last lens. The n may be an integer equal to or greater than 4, for example, in the range of 4 to 7 or 4 to 6. The ratio of spherical lenses to aspherical lenses in the n lenses may be any one of 3:1, 4:1, 3:2, 2:3, 3:3, 5:2, and 4:2.

[0049] In the receiving optical system 100, the first lens 101 may be made of glass. The glass material has little expansion and contraction due to changes in external temperature, and its surface is scratch-resistant, preventing surface damage. Therefore, in the optical system 100, the object-side lens may be a spherical lens, and the sensor-side lens may be an aspherical lens. At least one lens adjacent to the image sensor 151 in the optical system 100 may be an aspherical lens. For example, at least two lenses adjacent to the image sensor 151 may be aspherical lenses, and preferably the two lenses adjacent to the image sensor 151 may be aspherical lenses. That is, since the nth and (n-1)th lenses in the optical system 100 are aspherical lenses, various aberrations can be corrected for light incident on the image sensor 151.

[0050] At least two lenses adjacent to the object in the optical system 100 may be made of glass. Two or more lenses, for example, two to four lenses, adjacent to the object may be made of glass. Since the glass lenses have a smaller rate of change in contraction and expansion due to temperature changes than plastic lenses, the glass lenses may be disposed in a region adjacent to the exterior within the lens barrel. In the optical system 100, at least two lenses adjacent to the image sensor may be made of glass molded material. The glass molded material may be made of the same material as the glass and may have an aspherical surface. Since the glass molded lenses have a smaller rate of change in contraction and expansion due to temperature changes than plastic lenses, the glass lenses may be disposed in a region adjacent to the exterior within the lens barrel.

[0051] Each lens 101-105 of the optical system 100 may have an object-side surface and a sensor-side surface. The lenses 101-105 may include an object-side spherical lens, a sensor-side spherical lens, and an object-side aspherical lens, and a sensor-side aspherical lens. The optical system may have a smaller number of aspherical lenses than spherical lenses. The optical system 100 can correct various aberrations by arranging the aspherical lenses adjacent to the image sensor 151. The spherical lenses may be made of glass, and the aspherical lenses may be made of molded glass. Among the lenses of the optical system 100, the lens with the highest refractive index may be a spherical lens, and the lens with the highest Abbe number may be a spherical lens. Since the lens with the highest refractive index is arranged on the object side, it is easy to change the radius of curvature of the second and subsequent lenses, and the center thickness can be increased.

[0052] The lens with the largest effective diameter in the optical system 100 may be located closest to the object and may be made of glass and be a spherical lens. The lens with the smallest effective diameter in the optical system 100 may be located between the aperture stop and the first lens 101 and be a glass lens. The average effective diameter of the aspherical lenses may be smaller than the average effective diameter of the spherical lenses. Here, the effective diameter of the lenses is the average of the effective diameters of the object-side surface and the sensor-side surface of each lens. The optical system 100 can be miniaturized by adjusting the effective diameter of each lens. Each of the lenses 101-105 may include an effective area and a non-effective area. The effective area may be an area through which light incident on each lens passes. That is, the effective area may be defined as an effective area or an effective area where incident light is refracted to realize optical characteristics. The non-effective area is disposed around the effective area. The non-effective area may be an area on the lenses where effective light does not enter. That is, the non-effective area may be an area unrelated to the optical characteristics. The end of the non-effective area may be an area that is fixed to a lens barrel (not shown) that houses the lens.

[0053] Among the lenses 101-105 of the optical system 100, the lens having the greatest center thickness may be an aspherical lens, and the lens having the greatest edge thickness may be an aspherical lens. This allows various aberrations to be corrected and optical performance to be improved even in the peripheral areas. The center thickness of the aspherical lens may be greater than the center thickness of the spherical lens. Such an aspherical lens is disposed adjacent to the image sensor 151, and can refract incident light to the entire area of ​​the image sensor 151.

[0054] In the optical system 100, the total top length (TTL) may be more than 10 times, for example, more than 10 times and less than 20 times, the ImgH. The TTL is the distance on the optical axis OA from the center of the object side of the first lens 101 to the top surface of the image sensor 151. The ImgH is the distance from the center of the image sensor 151 to the diagonal end, or 1 / 2 the maximum diagonal length of the image sensor 151. Furthermore, the effective diameter of each lens in the optical system 100 may be greater than the diagonal length of the image sensor 151. The optical system 100 may have an effective focal length EFL of 10 mm or less and an angle of view FOV of 60 degrees or more, and may be used as a standard receiving optical system in a vehicle sensor system. For example, the receiving optical system and sensor system according to the embodiments may be applied to a sensing device for an ADAS (Advanced Driving Assistance System) installed inside or outside a vehicle.

[0055] The optical system 100 satisfies the condition: 5 < TTL / (2×ImgH), and for example, it can satisfy 5 < TTL / (2×ImgH) < 15. Thereby, the central thickness of each lens can be increased along the optical axis OA, the size of the image sensor 151 can be reduced, and a vehicle lens optical system can be provided. Also, since it is used for a vehicle camera, temperature correction must be applied within the temperature range that is the temperature reliability evaluation standard for automotive electrical components, that is, -40°C to +120°C. That is, the lens must be configured so that the focus of the lens remains within the set range even when the lens expands or contracts in response to temperature changes. The overall effective focal length EFL is 10 mm or less, for example, in the range of 1 mm to 10 mm or in the range of 1 mm to 6 mm, and it can be composed of lenses made of a glass material capable of the aforementioned temperature correction. By shortening the effective focal length of the optical system, a wide angle can be realized.

[0056] The number of lenses having positive (+) refractive power within the optical system 100 may be the same as or more than the number of lenses having negative (-) refractive power. The number of lenses having positive (+) refractive power may be 50% or more compared to the total number of lenses. The average refractive index of the lenses having negative refractive power may be greater than the average of the lenses having positive refractive power. Thereby, the dispersion value of the lenses having positive refractive power may be greater than the dispersion value of the lenses having negative refractive power. Such an optical system 100 has a mixture of spherical lenses and aspherical lenses made of glass material, so various aberrations can be corrected and deterioration of optical performance can be prevented.

[0057] The effective diameter of the first lens 101 may be larger than the effective diameter of the last lens 105. Thereby, the brightness of the optical system can be controlled. By controlling the size of the effective diameter of each of the lenses 101 - 105, the optical system 100 can control the incident light to compensate for the resolution and the deterioration of optical characteristics due to temperature changes, improve the chromatic aberration control characteristics, and improve the vignetting characteristics of the optical system 100.

[0058] The optical system 100 may include a first lens 101 to a fifth lens 105 aligned along an optical axis OA from an object toward an image sensor. The first to fifth lenses 101 to 105 may be defined as a lens unit. The optical system 100 may include an optical filter 155, which may be disposed within the lens unit. The optical filter 155 may transmit a laser beam emitted from a transmission optical system (see 110 in FIG. 10) and block beams of other wavelengths. The transmitted laser beam may be in the range of 890 nm to 960 nm or 940 nm ±10 nm.

[0059] The optical filter 155 is disposed between two different lenses of the lenses. The fourth lens 104 is disposed on the sensor side of the optical filter 155 and may have a refractive index smaller than that of the first lens 101 and a central thickness larger than that of the first lens 101. The third lens 103 is disposed on the object side of the optical filter 155 and may have a central thickness larger than that of the first lens 101. A center distance CG3 between the third lens 103 and the fourth lens 104 may be larger than the thickness of the optical filter 155. The center distance between the third lens 103 and the fourth lens 104 may be the smallest center distance between adjacent lenses in the optical system 100.

[0060] In terms of the radius of curvature as an absolute value, the lens surface having the smallest radius of curvature relative to the optical axis OA in the optical system 100 may be the sensor side surface of the first or second lens 101 or 102 among the spherical surfaces. This allows the center distance between the first lens 101 and the second lens 102 or the center distance between the second lens 102 and the third lens 103 to be increased. The lens surface having the largest radius of curvature in the optical system 100 may be the object side surface of the second lens 102 among the spherical surfaces. Adjusting the radius of curvature of the lenses can prevent diffuse reflection between adjacent lens surfaces, reducing lens ghosts and preventing multi-path interference (MPI) caused by lens ghosts.

[0061] The optical system 100 or sensor system may include an image sensor 151. The image sensor 151 may detect light and convert it into an electrical signal. The image sensor 151 may detect light that has sequentially passed through the lenses. The image sensor 151 may include an element capable of detecting incident light, such as a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS). The length of the image sensor 151 is the maximum length in a diagonal direction perpendicular to the optical axis OA. The number of lenses having an effective diameter larger than the length of the image sensor 151 is four to six, and the number of lenses having an effective diameter smaller than the length of the image sensor 151 may be zero.

[0062] At least two lenses are disposed between the optical filter 155 and the image sensor 151. The fourth and fifth lenses 104 and 105 are disposed between the optical filter 155 and the image sensor 151. The lens disposed between the optical filter 155 and the image sensor 151 may be an aspherical lens. The optical filter 155 is disposed between the spherical third lens 103 and the aspherical fourth lens 104. The optical filter 155 is disposed between the sensor-side spherical surface of the third lens 103 and the object-side aspherical surface of the fourth lens 104. The optical filter 155 may be a bandpass filter that passes a laser beam in the range of 890 nm to 960 nm or 940 nm ± 10 nm. The optical filter 155 may pass light of a wavelength corresponding to the laser beam transmitted from the transmission optical system of the LiDAR device and block the remaining light corresponding to ambient light.

[0063] The cover glass 153 is disposed between the sensor-side lens of the optical filter 155 and the image sensor 151 to protect the upper part of the image sensor 151 and prevent a decrease in reliability of the image sensor 151. The cover glass 153 may be removed or may be a protective glass.

[0064] The optical system 100 may include a stop ST. The stop ST adjusts the amount of light incident on the optical system 100. The stop ST is disposed between the third lens 103 and the fourth lens 104. The stop ST is disposed between the spherical third lens 103 and the aspherical fourth lens 104. The stop ST is disposed between the sensor-side spherical surface of the third lens 103 and the object-side aspherical surface of the fourth lens 104. The stop ST is disposed between the third lens 103 and the optical filter 155. In the lens disposed between the object and the stop ST, the effective diameter of the lens surface tends to increase from the second lens 102 to the stop ST. In the lens surface disposed between the stop ST and the image sensor 151, the effective diameter of the lens surface tends to decrease from the stop ST toward the image sensor 151. The tendency for the effective diameter of the lens surface to increase or decrease does not necessarily mean that the effective diameter of the lens surface increases or decreases. For example, this also includes a case where the effective diameter of the lens surface decreases as it increases from the aperture stop ST toward the sensor side.

[0065] The lens surface on which the aperture ST is disposed is intended to more efficiently adjust and guide the amount of light in the optical system 100. As in the embodiment, the aperture ST may be disposed on the sensor side of the third lens 103. Alternatively, the aperture ST may be disposed around the object side or sensor side of the second lens 102. Alternatively, at least one lens selected from the plurality of lenses, for example, the object side or sensor side of the third lens 103, may function as the aperture.

[0066] In the optical system 100 according to the embodiment, the sum of the refractive indices of the lenses may be 8.0 or more, for example, in the range of 8.0 to 12.0, and the average of the refractive indices may be in the range of 1.70 to 1.80. The sum of the Abbe numbers of the lenses may be 200 or less, for example, in the range of 130 to 200, and the average of the Abbe numbers may be 50 or less, for example, in the range of 25 to 50. The refractive indices of the lenses in the optical system 100 may be adjusted to prevent degradation of optical performance due to temperature changes from -45 to 120 degrees and optimize thermal compensation. Furthermore, the Abbe numbers may be adjusted to minimize deviations in spot size of incident light, i.e., minimize spot diagram size. The sum of the center thicknesses of all lenses may be 15 mm or more, for example, in the range of 15 mm to 25 mm, and the average center thickness may be 4.9 mm or less, for example, in the range of 2.9 mm to 4.9 mm. The sum of the center distances between the lenses along the optical axis OA may be 15 mm or more, for example, in the range of 15 mm to 30 mm, and is greater than the sum of the center thicknesses of the lenses. In addition, the average effective diameter of each lens surface of the optical system 100 can be 20 mm or less, for example, in the range of 9 mm to 20 mm. By adjusting the thickness of each lens in the optical system 100, it is possible to prevent degradation of optical performance due to temperature changes from -45 to 120 degrees and optimize thermal compensation.

[0067] The optical system according to an embodiment of the invention may have an angle of view exceeding 100 degrees, for example, 110 degrees or more, for example, in the range of 120±10 degrees. The F-number of the optical system or camera module may be 1.2 or less, for example, in the range of 0.7 to 1.2 or 0.7 to 0.9. The diagonal length of the image sensor 151 may be 6.041 mm±0.5 mm, which may be greater than the vertical height of the sensor. The invention can be provided to a vehicle LiDAR device that can suppress changes in the focal position due to temperature changes by stacking glass lenses and correct various aberrations by providing aspherical lenses.

[0068] Since the embodiment is an optical system applied to a LiDAR device, the first lens 101 may be made of glass. Glass has advantages over plastic in that it is scratch-resistant and less sensitive to external temperatures. A glass lens may be used as the first lens 101 to more effectively prevent scratches caused by foreign objects disposed inside the vehicle, and the object side of the first lens 101 may have a convex shape to prevent accumulation of foreign objects. The LiDAR device can detect the distance, direction, speed, temperature, and material distribution and concentration characteristics of an object while the vehicle is in operation. Such a LiDAR device can be used for an advanced driver assistance system (ADAS). The optical system 100 according to the embodiment may further include a reflecting member (not shown) for changing the path of light. The reflecting member may be implemented as a prism that reflects incident light toward the lens. The optical system according to the embodiment will now be described in detail.

[0069] 1 to 8 show a receiving optical system according to an embodiment of the present invention. Referring to FIGS. 1 to 4, the first to fifth lenses 101-105 of the receiving optical system 100 can transmit light reflected by an object to the image sensor 151. The optical filter 155 is located closer to the object than the fifth lens 105, which is the last lens, and passes a required wavelength band while blocking other wavelength bands. The aperture ST may be arranged around the sensor side of the third lens 103.

[0070] The first lens 101 can have a positive (+) or negative (-) refractive power with respect to the optical axis OA. The first lens 101 may have a negative (-) refractive power. The first lens 101 can include a plastic material or a glass material, for example, it may be a glass material. The first lens 101 made of the glass material can reduce changes such as the central position and the radius of curvature due to temperature changes according to the surrounding environment, and can protect the incident side surface of the optical system 100. The first lens 101 is a glass material that is not injection-molded. On the optical axis, the first surface S1 on the object side of the first lens 101 can be convex, and the second surface S2 on the sensor side can be concave. The first surface S1 and the second surface S2 can have spherical surfaces. The first lens 101 can have a meniscus shape bulging toward the object side. Alternatively, the first surface S1 can be concave and the second surface S2 can be convex with respect to the optical axis OA. Since the first surface S1 is convex and the second surface S2 is concave, the incident light can be refracted in a direction close to the optical axis OA, the distance between the first and second lenses 101 and 102 can be reduced, and the effective diameter of the second lens 102 can be reduced. The effective diameter of the sensor side surface of the second lens 102 can be designed to be smaller than the effective diameter of the object side surface according to the shape of the lens surface of the first lens 101. The first surface S1 of the first lens 101 is provided from the optical axis OA to the end of the effective region, that is, the edge, without a critical point. The second surface S2 of the first lens 101 is provided without a critical point. When the refractive index of the first lens 101 is n1, the condition 1.7 < n1 or 1.75 < n1 < 2.1 can be satisfied. Since the refractive index n1 of the first lens 101 is higher than that of other lenses, the radius of curvature of the first surface S1 of the first lens 101 can be increased, making the production of the lens easier. When the refractive index n1 of the first lens 101 is smaller than the above condition, the lens surface must be formed to rapidly recess or bulge in order to increase the refractive power of the first and second lenses 101 and 102. In this case, the production of the lens is difficult, the defect rate of the lens also increases, causing a decrease in the yield.

[0071] The second lens 102 is disposed between the first lens 101 and the third lens 103. The second lens 102 can have a positive (+) or negative (−) refractive power with respect to the optical axis OA. The second lens 102 can have a negative (−) refractive power. The second lens 102 can include a plastic or glass material and may be provided, for example, with a glass material. The second lens 102 is a glass material that is not injection molded. On the optical axis OA, the third surface S3 on the object side of the second lens 102 is flat, and the fourth surface S4 on the sensor side can have a concave shape. The fourth surface S4 may be spherical. The fourth surface S4 is provided without a critical point from the optical axis OA to the end of the effective region. Alternatively, the third surface S3 can have a convex shape and the fourth surface S4 can have a concave shape. Alternatively, the second lens 102 can have both surfaces concave. When the refractive index of the second lens 102 is n2, the condition 1.7 < n2 or 1.75 < n2 < 2.1 can be satisfied. Since the refractive index n2 of the second lens 102 is higher than that of other lenses, the radius of curvature of the third surface S3 of the second lens 102 can be increased, facilitating the manufacture of the lens.

[0072] Since the fourth surface S4 on the sensor side of the second lens 102 has a concave shape and a small radius of curvature, the center distance between the second lens 102 and the third lens 103 can be separated. Also, when the radius of curvature of the third surface S3 of the second lens 102 is L2R1 and the radius of curvature of the fourth surface S4 is L2R2, the condition L2R1 > L2R2 can be satisfied. When this condition is satisfied, the fourth surface S4 can efficiently refract light and guide it so that the effective diameters of the third to fifth lenses 103 to 105 do not increase, reducing the TTL. If the condition is L2R1 < L2R2, a large amount of aberration occurs on the object side surface of the second lens 102, the light refraction efficiency decreases on the sensor side surface, the effective diameter of the rear lens increases, and the TTL also increases.

[0073] The third lens 103 can have a positive (+) or negative (-) refractive power with respect to the optical axis OA. The third lens 103 may have a positive (+) refractive power. The third lens 103 can include a plastic or glass material, for example, it may be a glass material. The third lens 103 is a glass material that has not been injection-molded. On the optical axis, the object-side fifth surface S5 of the third lens 103 has a convex shape, and the sensor-side sixth surface S6 can have a convex shape. The third lens 103 can have convex shapes on both surfaces with respect to the optical axis OA. At least one or both of the fifth surface S5 and the sixth surface S6 may be spherical surfaces. At least one or both of the fifth surface S5 and the sixth surface S6 may be provided without a critical point from the optical axis OA to the end of the effective region. Alternatively, the third lens 103 can have a meniscus shape bulging on the object side or the sensor side. Or, the third lens 103 can have concave shapes on both surfaces with respect to the optical axis. When the refractive index of the third lens 103 is n3, the conditions n3 < n1 and n3 < n2 can be satisfied. When the Abbe number of the third lens 103 is v3, the conditions v3 < v1 and v3 < v2 can be satisfied.

[0074] The aperture ST is disposed around the sensor-side sixth surface S6 of the third lens 103. Since the third lens 103 adjacent to the object side of the aperture ST has a positive refractive power (F3 > 0), the third lens 103 can refract the incident light in the optical axis direction, and it is possible to suppress an increase in the effective diameter of the sensor side or the rear-side lens of the third lens 103. Thereby, it is possible to prevent a decrease in the yield by weight of the optical system by the third lens 103 and improve the production efficiency. Here, the focal lengths of the fourth and fifth lenses 104 and 105 disposed on the sensor side of the aperture ST can have positive values, and the TTL can be reduced within the angle-of-view range.

[0075] Since the sixth surface S6 of the third lens 103 on the sensor side has a convex shape, the effective diameter of the optical filter 155 disposed on the sensor side of the third lens 103 may be larger than the effective diameter of the sixth surface S6 of the third lens 103. The optical filter 155 transmits the laser beam emitted by the transmission optical system of the LiDAR device and blocks beams of other wavelengths.

[0076] The fourth lens 104 may have positive (+) or negative (-) refractive power on the optical axis OA. The fourth lens 104 may have positive (+) refractive power. The fourth lens 104 may include plastic or glass, and may be made of glass. The fourth lens 104 may be injection molded. The object-side seventh surface S7 of the fourth lens 104 may have a convex shape on the optical axis, and the sensor-side eighth surface S8 may have a convex shape on the optical axis. The fourth lens 104 may have convex surfaces on both sides. At least one or both of the seventh surface S7 and the eighth surface S8 may be aspherical. The aspherical coefficients of the seventh and eighth surfaces S7 and S8 may be represented by S1 and S2 of L4 in FIG. 3. The seventh surface S7 may have a critical point from the optical axis OA to the end of the effective area. The eighth surface S8 is provided without a critical point from the optical axis OA to the end of the effective area. The seventh surface S7 and the eighth surface S8 may both have a critical point or no critical point. Here, the critical point may refer to a point where the sign of the slope with respect to the optical axis OA and a direction perpendicular to the optical axis OA changes from positive (+) to negative (-) or from negative (-) to positive (+), and the slope value becomes zero. The critical point may also be a point where the slope of a tangent passing through the lens surface decreases or increases while decreasing. Alternatively, the fourth lens 104 may have a meniscus shape that bulges toward the object side or the sensor side. Alternatively, the fourth lens 104 may have a concave shape on both sides of the optical axis OA.

[0077] The fifth lens 105 may have positive (+) or negative (-) refractive power on the optical axis OA. The fifth lens 105 may have positive (+) refractive power. The fifth lens 105 may include plastic or glass, and may be made of glass. The fifth lens 105 may be injection molded. On the optical axis, the ninth object-side surface S9 of the fifth lens 105 may have a convex shape, and the tenth sensor-side surface S10 may have a convex shape. The fifth lens 105 may have convex surfaces on both sides. Alternatively, on the optical axis OA, the fifth lens 105 may have concave surfaces on both sides. At least one or both of the ninth surface S9 and the tenth surface S10 may be aspherical. The aspherical coefficients of the ninth and tenth surfaces S9 and S10 may be represented by L1 and L2 of L5 in FIG. 3. Both the ninth surface S9 and the tenth surface S10 may be without critical points. Alternatively, at least one or both of the ninth and tenth surfaces S9 and S10 may have a critical point from the optical axis OA to the end of the effective area.

[0078] The effective diameter of the fifth lens 105 may be smaller than the effective diameter of the fourth lens 104. The fifth lens 105 may have a refractive index lower than that of the first and second lenses 101 and 102 and may have an Abbe number lower than that of the first and second lenses 101 and 102. The third lens 103, the fourth lens 104, and the fifth lens 105 may have convex surfaces on both sides and may all have positive refractive power. The third lens 103, the fourth lens 104, and the fifth lens 105 may have a refractive index lower than that of the first and second lenses 101 and 102 and may have an Abbe number lower than that of the first and second lenses 101 and 102. At least one of the object-side surface and the sensor-side surface of the fourth and fifth lenses 104 and 105 may have a free-form surface, i.e., a non-rotationally symmetric curved surface.

[0079] The fifth lens 105 may be an aspherical lens closest to the image sensor 151. By arranging two or more aspherical lenses adjacent to the image sensor 151, the aspherical lens surfaces can improve aberrations such as spherical aberration and chromatic aberration, and can control the impact on resolution. The aspherical lens surfaces of the lenses adjacent to the image sensor 151 can improve optical performance, for example, improving aberration characteristics and preventing a decrease in resolution.

[0080] When the lens having negative refractive power is in the first lens group and the lens having positive refractive power is in the second lens group, the aperture ST and the optical filter 155 may be disposed in the second lens group. The aperture ST and the optical filter 155 are disposed between the first lens group, at least one of whose object-side surface and whose sensor-side surface is spherical, and the second lens group, at least one of whose object-side surface and whose sensor-side surface is aspherical. The aperture ST and the optical filter 155 are disposed between the first lens group having a lens that is not injection-molded and the second lens group having a lens that is injection-molded. The aperture ST and the optical filter 155 are disposed between the first lens group having a lens disposed on the object side of the aperture ST and the second lens group having a lens disposed on the sensor side of the optical filter 155.

[0081] Fig. 2 shows an example of lens data for the optical system of the embodiment shown in Fig. 1. As shown in Fig. 2, the radius of curvature (Radius) of the first to fifth lenses 101, 102, 103, 104, and 105 on the optical axis OA, the center thickness CT of the lenses, the center gap or center distance CG between the lenses, the refractive index at the d-line, the Abbe number, and the effective radius can be set.

[0082] As shown in Figures 1 and 2, the center thicknesses of the first to fifth lenses 101 to 105 are indicated by CT1 to CT5, the edge thicknesses at the ends of the effective areas of each lens are indicated by ET1 to ET5, and the center distances between adjacent lenses are indicated by CG1 to CG4.

[0083] The first to fifth lenses 101 to 105 can satisfy the following conditions.

[0084] Condition 1: CT2 <CT1<CT3 Condition 2: CT4 <CT5<(CT3+CT4) Condition 3: CT3-CT4 <CT2 Condition 4: ET3 <ET2<ET1 Condition 5: ET4 <ET3<ET5<CT5 Condition 6: CT2 <CT1<ET2<ET1 Condition 7:CG1 <CT4<CT5<CG2 Condition: CT1 <CG3<CG4<CG1 The center thickness CT5 of the fifth lens 105 is the largest among the lenses, and the center thickness CT2 of the second lens 102 is the smallest among the lenses. The maximum center thickness may be at least twice the minimum center thickness, and the difference between the maximum and minimum center thicknesses may be at least 4 mm. That is, even if a lens made of a spherical material has a thin center thickness, the optical performance does not deteriorate and the thickness of the sensor system can be slimmed down. The thickness of such a lens can be adjusted to perform thermal compensation for temperatures that vary from low to high.

[0085] Regarding the center distance CG between adjacent lenses, the center distance CG2 between the second lens 102 and the third lens 103 is the maximum and is larger than the center distance CG1 between the first and second lenses 101 and 102. The center distance between the third and fourth lenses 103 and 104 is the minimum. Here, the difference between the maximum center distance and the minimum center distance may be 5 mm or more, for example, in the range of 5 mm to 8 mm. In addition, by providing the maximum center distance between the lenses to be larger than the maximum center thickness of each lens, it is possible to provide a receiving optical system in which the center distance between the aspherical lenses does not increase. In addition, since the maximum center distance between the lenses is provided to be larger than the minimum center thickness of each lens, it is possible to control the optical path.

[0086] Regarding the effective diameter, the lens having the largest effective diameter may be the first lens 101 closest to the object. The lens having the largest effective diameter may be a spherical lens made of glass. The lens surface having the largest effective diameter may be the first surface S1 of the first lens 101. The lens having the smallest effective diameter may be the second lens 102 adjacent to the first lens 101. The lens surface having the smallest effective diameter may be the fourth surface S4 of the second lens 102, and may be less than 70% of the first surface S1. The effective diameters of each of the first to fifth lenses 101-105 may be greater than the diagonal length of the image sensor 151. Here, the sum of the central thicknesses of the first to third lenses 101-103 may be smaller than the sum of the central thicknesses of the fourth and fifth lenses 104 and 105. The average effective diameter of the first to third lenses 101-103 may be greater than the average effective diameter of the fourth and fifth lenses 104 and 105. The fourth and fifth lenses 104 and 105 have aspherical surfaces and can guide the light incident through the spherical lenses to the image sensor 151 .

[0087] Comparing the absolute focal lengths, the fourth lens 104 has the longest focal length among the lenses, and can be between 20 mm and 40 mm. This allows the optical system to have improved MTF characteristics, aberration control characteristics, resolution characteristics, etc. within the range of the angle of view set by the optical system, and good optical performance can be achieved at the periphery of the angle of view.

[0088] As shown in Figure 3, the lens surfaces of the fourth and fifth lenses 104 and 105 may include aspherical surfaces with 12th-order or higher aspherical coefficients, for example, 30th-order aspherical coefficients. That is, the object-side and sensor-side surfaces of the fourth and fifth lenses 104 and 105 may have lens surfaces with 12th-order aspherical coefficients. In Figure 3, Y is the radius of curvature and K is the Conic constant. Aspherical surfaces with at least 12th-order aspherical coefficients A, B, C, D, and E (values ​​other than "0") can significantly change the aspherical shape in the peripheral area, thereby enabling excellent correction of the optical performance in the peripheral area of ​​the field of view (FOV).

[0089] The focal lengths F1 and F2 of the first and second lenses 101 and 102 may have negative refractive power, and the focal lengths F3, F4 and F5 of the third, fourth and fifth lenses 103, 104 and 105 may have positive refractive power. In addition, the second lens 102 and the third lens 103, which are adjacent lenses, may satisfy the following condition:

[0090] Condition 1: Refractive index of lens with positive refractive power < Refractive index of lens with negative refractive power Condition 2: Dispersion value of a lens with positive refractive power > Dispersion value of a lens with negative refractive power Here, the second lens 102 of the lenses has negative refractive power, and the third lens 103 has positive refractive power. Therefore, according to conditions 1 and 2, the refractive index of the third lens is greater than the refractive index of the second lens, and the dispersion value of the third lens is smaller than the dispersion value of the second lens. Chromatic aberration occurring in a spherical lens can be corrected by the spherical lens. Furthermore, the difference in refractive index between the second lens 102 and the third lens 103, which are consecutively arranged spherical lenses, is between 0.1 and 0.15, and the difference in Abbe number is between 10 and 20, so that chromatic aberration occurring in the spherical lens can be compensated by the spherical lens.

[0091] Chromatic aberration occurs in optical systems, and is corrected using successively arranged aspherical lenses. Lenses repeatedly contract and expand as temperatures change from low to high. Lenses made of the same material exhibit the same degree of change in lens characteristics with temperature, so it is effective to correct chromatic aberration between lenses made of the same material even when the temperature changes. For example, as shown in Figure 4, when the temperature of the lens barrel or receiving optical system changes from -40 degrees to 90 degrees, the refractive index of the first to fourth lenses at the d-line remains almost unchanged. Therefore, in this embodiment of the invention, the fourth lens 104 and the fifth lens 105 can correct chromatic aberration that occurs in spherical lenses made of glass.

[0092] Figure 5 is a graph showing the diffraction MTF at low, room, and high temperatures for the optical system of Figure 1, illustrating the luminance modulation as a function of spatial frequency. As shown in Figure 5, in an embodiment of the invention, the deviation of MTF at low or high temperatures from room temperature can be less than 10%, i.e., 7% or less. Each MTF curve was measured in 0.302 mm increments from 0.000 mm to 3.020 mm.

[0093] 6 to 9 are graphs showing the aberration characteristics of the optical system of FIG. 1 at low, room, and high temperatures. The aberration graphs of FIGS. 6 to 9 show the spherical aberration, astigmatic field curves, and distortion measured from left to right. In FIGS. 6 to 9, the X-axis represents focal length (mm) and distortion (%), and the Y-axis represents image height. The spherical aberration graphs are for light in wavelength bands of approximately 930 nm, 940 nm, and 950 nm, while the astigmatic and distortion graphs are for light in a wavelength band of approximately 940 nm. In the aberration graphs of FIGS. 6 to 9, the closer the curves at low, room, and high temperatures are to the Y-axis, the better the aberration correction function. That is, the optical system 100 according to the embodiment has improved resolving power and can provide good optical performance both at the center and periphery of the FOV. Here, low temperature can be -20°C or lower, for example, in the range of -20 to -50°C, normal temperature can be in the range of 22°C ±5°C or in the range of 18°C ​​to 27°C, and high temperature can be 85°C or higher, for example, in the range of 85°C to 120°C. From this, it can be seen that the decrease in luminance ratio (modulation) from low to high temperatures in Figures 6 to 9 is less than 10%, for example, 5% or less, or is almost unchanged. The MTF deviation according to temperature is shown in Table 1. [Table 1]

[0094] Table 2 compares the changes in optical characteristics such as EFL, BFL, F-number (F#), TTL, and field of view (FOV) at room temperature, low temperature, and high temperature in the receiving optical system of the embodiment, and shows that the rate of change in optical characteristics at low temperatures relative to room temperature is 5% or less, for example, 3% or less or 2% or less, and that the rate of change in optical characteristics at high temperatures relative to room temperature is 5% or less, for example, 3% or less or 2% or less. [Table 2]

[0095] Therefore, as shown in Table 2, the change in optical characteristics due to temperature changes from low to high, such as the rate of change in effective focal length (EFL), TTL, BFL, F-number, and FOV, is 10% or less, i.e., 5% or less, for example, in the range of 0 to 5%. This means that even if at least one or two or more aspherical lenses are used, a design that allows temperature compensation for the aspherical lenses can be performed can prevent a decrease in the reliability of the optical characteristics. The optical system of the disclosed embodiment can effectively control aberration characteristics such as chromatic aberration and distortion, and can have good optical performance both in the center and periphery of the FOV.

[0096] The receiving optical system can prevent degradation of optical performance from low to high temperatures, taking into account the characteristics of the vehicle optical system. For example, after designing lenses at room temperature, the refractive index change coefficient (dn / dt) for each temperature can be calculated by considering the power combination of each lens. The temperature coefficient (dn / dt) corresponding to the refractive index of the lens and the defocus for thickness variations at low, room, and high temperatures can be set to 5 μm or less. To this end, the first to third lenses 101, 102, and 103 are made of spherical glass material, and the fourth and fifth lenses 104 and 105 are made of aspherical glass material. Conventional filters are disposed between the image sensor and the last lens. In this embodiment of the invention, the optical filter 155 can be disposed close to the aperture ST, i.e., between the aperture ST and the fourth lens 104. This minimizes the incident angle of light incident on the optical filter 155. That is, the incident angle of the main beam incident on the optical filter 155 can be less than 20 degrees, i.e., 18 degrees or less.

[0097] This overcomes the physical limitation of the filter transmittance range shifting depending on the angle of incidence of the optical filter 155. For example, when a conventional filter is placed between the image sensor and the final lens, the angle of incidence of the main beam on the filter is approximately 45 degrees. However, when the optical filter 155 of the present invention is placed around the periphery of the aperture stop ST, the angle of incidence of the main beam is reduced to less than 20 degrees, e.g., 18 degrees or less. Considering the transmittance curves when the main beam is incident on the optical filter 155 at an angle of 0 degrees, 20 degrees, and 40 degrees, it is possible to achieve a wider filter area utilization from an angle of incidence of the main beam from 0 degrees to less than 20 degrees. Figure 9 is a graph showing the transmittance (%) curves when the angle of incidence of the main beam on the filter of the present invention is 0 degrees, 20 degrees, and 40 degrees. The angles of incidence of the main beam on the incident surface of the optical filter 155 are as shown in Table 3. As can be seen from the angle of incidence (AOI) data in Table 3, the angle of incidence in different directions (±Y direction, ±X direction) from the main beam (chief ray) incident on the filter from 0 field to 1.05 field ranges from 0 degrees to a maximum of 17.55 degrees. This minimizes the problem of the angle of incidence (AOI) of the main beam shifting at low and high temperatures compared to room temperature. [Table 3]

[0098] The optical system 100 according to the embodiment disclosed above can satisfy at least one or two or more of the mathematical formulas described below. Thereby, the optical system 100 according to the embodiment can have improved optical characteristics. For example, when the optical system 100 satisfies at least one mathematical formula, the optical system 100 can effectively control aberration characteristics such as chromatic aberration and distortion aberration, and can have good optical performance at both the center and periphery of the angle of view FOV. In addition, the optical system 100 can have improved resolution. Also, for the meaning of the thickness of the lens on the optical axis OA described in the mathematical formula and the distance between adjacent lenses on the optical axis OA, reference can be made to the embodiments disclosed above.

[0099] [Equation 1] 0 < CT1 / CT2 < 3 By setting the center thickness CT1 of the first lens 101 and the center thickness CT2 of the second lens 102 in Equation 1, it is possible to prevent a decrease in the rigidity of the first lens 101 and control factors that affect aberration. Preferably, Equation 1 can satisfy 1 < CT1 / CT2 < 3.

[0100] [Equation 2] 5 < CA11 / CT1 < 15 CA11 is the effective diameter of the object side surface S1 of the first lens 101. By setting the center thickness CT1 of the first lens 101 and the effective diameter CA11 of the object side surface S1 of the first lens 101 in Equation 2, when this is satisfied, it is possible to prevent a decrease in the strength and optical characteristics of the lens made of glass material. If it is lower than the range of Equation 1, the lens may be damaged or the incident efficiency may decrease, and if it is larger than the range, the TTL increases and the weight of the optical system becomes heavier. Preferably, Equation 2 can satisfy 7 < CA11 / CT1 < 12.

[0101] [Equation 3] 0 < CT5 / CT4 < 3 The central thickness CT5 of the fifth lens 105 and the central thickness CT4 of the fourth lens 104 can be set by Equation 3, heat compensation can be optimized according to the temperature change from low temperature to high temperature, and the degradation of optical performance can be prevented. Preferably, Equation 3 can satisfy 1 < CT5 / CT4 < 2.

[0102] [Equation 3-1] 0 < CT5 / CT3 < 3 By setting the central thicknesses CT3 and CT5 of the third and fifth lenses 103 and 105 with Equation 3-1, the light refracted by the object-side lens can be guided to the image sensor 151. Preferably, Equation 3-1 can satisfy 1 < CT5 / CT3 < 2. Thereby, the fifth lens 105 adjacent to the image sensor 151 thickens the central thickness CT5, and without significantly increasing the effective diameter, the light refracted by the object-side lens can be refracted to the entire area of the image sensor 151.

[0103] [Equation 4] 0 < CT5 / (CT1 + CT2) < 3 By setting the central thickness CT5 of the fifth lens 105 to be larger than the sum of the central thicknesses CT1 and CT2 of the first and second lenses 101 and 102 with Equation 4, the light refracted by the object-side lens can be guided to the image sensor 151. Preferably, Equation 4 can satisfy 1 < CT5 / (CT1 + CT2) < 2. Thereby, the fifth lens 105 adjacent to the image sensor 151 thickens the central thickness CT5 and does not significantly increase the effective diameter.

[0104] [Equation 5] 0 < CT5 / CG2 < 1.5 By setting the central interval CG2 between the second and third lenses 102 and 103 to be larger than the central thickness CT5 of the fifth lens 105 with Equation 5, the second lens 102 can be set as a lens with a concave sensor side surface and a minimum effective diameter. Also, the effective diameter of the third lens 103 can be increased compared to the effective diameter of the second lens 102. Preferably, 0.5 < CT5 / CG2 < 1 can be satisfied.

[0105] [Equation 6] 0 < CG4 / CG1 < 1.5 By setting the center distance CG1 between the first and second lenses 101 and 102 and the center distance CG4 between the fourth and fifth lenses 104 and 105 in Equation 6, the center distance between the spherical lenses and the center distance between the aspherical lenses can be set. Preferably, 0.5 < CG4 / CG1 < 1 can be satisfied.

[0106] [Equation 6-1] 0 < CG4 / CG2 < 1 By setting the center distance CG2 between the second and third lenses 102 and 103 to be larger than the center distance CG4 between the fourth and fifth lenses 104 and 105 in Equation 6-1, the center distance between the aspherical lenses on the sensor side can be reduced by the center distance between the spherical lenses on the object side. Preferably, 0.3 < CG4 / CG2 < 0.8 can be satisfied.

[0107] [Equation 7] 1 < CG3 / FT < 7 FT is the thickness of the optical filter 155. By making the center distance CG3 between the third and fourth lenses 103 and 104 larger than the thickness of the optical filter 155 in Equation 7, a space for arranging the optical filter 155 can be secured in the region between the third and fourth lenses 103 and 104. Preferably, 3 < CG3 / FT < 5 can be satisfied.

[0108] [Equation 8] 0.5 < CG2 / (CT1 + CG1 + CT2) < 1.5 In Equation 8, the center distance CG2 between the second and third lenses 102 and 103 can be set to be larger than the optical axis distance between the object side surface of the first lens 101 and the sensor side surface of the second lens 102. Thereby, the effective diameter of the object side surface of the first lens 101 can be set to the maximum, and the second lens 102 can be set to a lens having a concave sensor side surface and a minimum effective diameter. Preferably, 1 < CG2 / (CT1 + CG1 + CT2) < 1.5 can be satisfied. [[ID=SO]]

[0109] [Equation 10] 1.70 < n1 n1 is the refractive index at the d-line of the first lens 101. By setting the refractive index of the first lens 101 high in Equation 10, factors affecting the reduction of the third-order aberration (Seidel aberration) of the optical system can be adjusted, and aberrations that may occur with a slightly longer TTL can be reduced. Equation 10 can preferably satisfy 1.75 < n1 < 2.1. When designed lower than the lower limit value of Equation 10, the aberration improvement decreases, the refractive power of the first lens becomes weak and light cannot be efficiently collected, and the performance of the optical system deteriorates. When designed higher than the upper limit value of Equation 10, there is a disadvantage that it becomes difficult to obtain materials. Also, when the refractive index of the first lens 101 is designed lower than the lower limit value of Equation 10, the curvature radii of the first and second lenses increase in order to increase the refractive power of the first and second lenses.

[0110] [Equation 10-1] 1.7 < Aver(n1:n5) < 1.8 Aver(n1:n5) is the average of the refractive index values at the d-line of the first to fifth lenses. When Equation 10-1 is satisfied, the optical system 100 can set the resolution and suppress the influence on the TTL.

[0111] [Equation 10-2] GMn_Aver < GLn_Aver GLn_Aver is the average of the refractive index values at the d-line of the spherical glass lenses, and GMn_Aver is the average of the refractive index values at the d-line of the aspherical glass lenses which are glass molds. The spherical lens is a lens made of a glass material that is not injection molded, and the aspherical lens is a lens made of an injection molded glass material. A spherical lens with a high refractive index is located on the object side of the aspherical lens, and the chromatic dispersion can be increased.

[0112] [Equation 11] 0 < n1 / n3 < 1.5 n1 and n3 are the refractive indices of the first and third lenses 101 and 103 at the d-line. By reducing the difference between the refractive index of the first lens 101 and the refractive index of the third lens 103 in Equation 11, it is possible to prevent a decrease in chromatic dispersion due to the glass material lens. Preferably, Equation 11 can satisfy 1 < n1 / n3 < 1.3.

[0113] [Equation 12] 0 < n3 / n4 < 1.5 n3 and n4 are the refractive indices of the third and fourth lenses 103 and 104 at the d-line. By setting the refractive index of the third lens 103 higher than the refractive index of the fourth lens 104 in Equation 12, it is possible to adjust the chromatic dispersion due to the spherical material lens and the chromatic dispersion due to the aspherical lens. Preferably, Equation 12 can satisfy 1 < n3 / n4 < 1.2.

[0114] [Equation 13] (v4 × n4) < (v1 × n1) n1 and n4 are the refractive indices of the first and fourth lenses 101 and 104 at the d-line, and v1 and v4 are the Abbe numbers of the first and fourth lenses. By setting the product of the refractive index and the Abbe number of the first lens 101 higher than the product of the refractive index and the Abbe number of the fourth lens 104 in Equation 13, it is possible to adjust the chromatic dispersion due to the spherical material lens and the chromatic dispersion due to the aspherical lens.

[0115] [Equation 14] BFL < D1 BFL is the optical axis distance from the surface of the image sensor 151 to the center of the sensor side surface of the last lens, that is, the fifth lens, and D1 is the optical axis distance from the surface of the image sensor 151 to the surface of the optical filter 155. By satisfying Equation 14, the optical filter 155 can be arranged in the region adjacent to the aperture ST or positioned in the lens periphery closer to the object side than the last lens.

[0116] [Equation 14-1] 1 < SD / D1 < 1.2 SD is the distance in the optical axis direction from the aperture ST to the surface of the image sensor 151. When the mathematical formula 14-1 is satisfied, the optical filter 155 is adjacent to the aperture ST and is arranged closer to the image sensor 151 than the aperture ST.

[0117] [Mathematical formula 15] (CT n +CT n-1 )<D1 CT n is the central thickness of the nth lens adjacent to the image sensor 151, CT n-1 indicates the central thickness of the (n - 1)th lens, and D1 is the optical axis distance from the surface of the image sensor 151 to the optical filter 155. In the mathematical formula 15, the optical axis distance between the optical filter 155 and the image sensor 151 can be set to be greater than the sum of the central thicknesses of the nth lens adjacent to the image sensor 151 and the (n - 1)th lens. The nth lens may be the fifth lens, and the (n - 1)th lens may be the fourth lens. Thereby, the incident angle of the main beam incident on the optical filter 155 can be reduced to less than 20 degrees, and the problem that the incident angle shifts at normal temperature compared to low temperature and high temperature can be minimized.

[0118] [Mathematical formula 15-1] (CT n +CT n-1 )<D1<TTL / 2 TTL is the optical axis distance from the center of the object side surface of the first lens 101 to the surface of the image sensor 151. In the mathematical formula 15-1, the optical axis distance between the optical filter 155 and the image sensor 151 can be set to be less than 1 / 2 of the overall optical axis length TTL. Thereby, the incident angle of the main beam incident on the optical filter 155 can be reduced to less than 20 degrees, and the problem that the incident angle shifts at normal temperature compared to low temperature and high temperature can be minimized. Preferably, D1 satisfies 18mm < D1 < 25mm.

[0119] [Mathematical formula 16] D1 < D2 D1 is the optical axis distance from the surface of the image sensor 151 to the optical filter 155, and D2 is the optical axis distance from the center of the object side surface of the first lens 101 to the object side surface of the optical filter 155. When the mathematical formula 16 is satisfied, the optical filter 155 is arranged between the lenses or at a position adjacent to the aperture ST between the third and fourth lenses. Thereby, the incident angle of the main beam incident on the optical filter 155 can be reduced to less than 20 degrees, and the problem that the incident angle at normal temperature, low temperature and high temperature is shifted can be minimized.

[0120] [Mathematical formula 17] 0 < FT < CG3 When the mathematical formula 17 is satisfied, the filter can be arranged between the third and fourth lenses. Also, 0 < FT < EG3 can be satisfied, where EG3 is the edge interval between the third and fourth lenses. Also, 0 < FT < CG_Min can be satisfied, where CG_Min represents the minimum interval among the center intervals between adjacent lenses.

[0121] [Mathematical formula 18] 1 < CA11 / CA21 < 5 CA21 means the effective diameter of the third surface S3 of the second lens 102. When the mathematical formula 18 is satisfied, the optical system 100 can control the incident light and set the elements affecting the aberration. Preferably, 1 < CA11 / CA21 < 2.5 can be satisfied.

[0122] [Mathematical formula 19] 0 < CA22 / CA31 < 1.5 CA22 means the effective diameter of the fourth surface S4 of the second lens 102, and CA31 means the effective diameter of the fifth surface S5 of the third lens 103. When the mathematical formula 19 is satisfied, the optical system 100 can control the incident light path and set the sensor side surface of the second lens 102 to be concave. Preferably, the mathematical formula 19 can satisfy 0.5 < CA22 / CA31 < 1.

[0123] [Mathematical formula 20] 0.5 < CA42 / CA51 < 2 CA42 means the effective diameter of the eighth surface S8 of the fourth lens 104, and CA51 means the effective diameter of the ninth surface S9 of the fifth lens 105. When Equation 20 is satisfied, the optical system 100 can set the optical path incident on the image sensor 151 through the fourth lens 104 and the fifth lens 105. Equation 20 can preferably satisfy 1 < CA42 / CA51 < 1.5.

[0124] [Equation 21] 1 < CA11 / CA51 < 5 When the optical system 100 satisfies Equation 21, the incident amount of the spherical lens, which is the first lens, can be increased, and the optical path of light to the image sensor can be set through the aspherical lens, which is the last lens. Equation 21 can preferably satisfy 1 < CA11 / CA51 < 2.5. [[ID=I3]]

[0125] [Equation 22] [[ID=1I7]]1 < CG2 / (CT2 + CT3) < 3 When Equation 22 is satisfied, the concave curvature radius of the sensor side surface of the second lens 102 can be set, and the optical path between the second and third lenses 102, 103 can be set. Preferably, it can satisfy 1 < CG2 / (CT2 + CT3) < 2.

[0126] [Equation 23] 0 < CG4 / (CT4 + CT5) < 1 When Equation 23 is satisfied, the curvature radius of the sensor side surface of the fourth lens 104 can be reduced, and the optical path corresponding to the center-to-center distance between the fourth and fifth lenses 104, 105 can be set. Preferably, it can satisfy 0 < CG4 / (CT4 + CT5) < 0.7.

[0127] [Equation 24] 1 < CG_Max / CG4 < 4 CG_Max means the maximum among the center distances between the lenses within the optical system. When Equation 24 is satisfied, the maximum center distance between the lenses can be positioned closer to the object side than the center distance between the fourth lens 104 and the fifth lens 105, and an increase in the size of the fourth lens 104 can be suppressed. Preferably, 1.5 < CG_Max / CG4 < 3 can be satisfied.

[0128] [Equation 25] 0 < CT5 / BFL < 4 CT5 is the center thickness of the fifth lens, and BFL is the optical axis distance from the center of the sensor side surface of the last lens to the image sensor 151. That is, BFL is the optical axis distance from the center of the sensor side surface of the fifth lens 105 to the surface of the image sensor 151. When Equation 25 is satisfied, the incident light is stably transmitted to the entire area of the image sensor 151 by the fifth lens 105. Preferably, 1 < CT5 / BFL < 3 can be satisfied. Here, CT5 is the maximum among the center thicknesses of the lenses.

[0129] [Equation 26] 0 < CG3 / CT5 < 1.5 When Equation 26 is satisfied, the effective diameter of the fifth lens 105 can be adjusted. Preferably, 0.1 < CG3 / CT5 < 1 can be satisfied.

[0130] [Equation 27] 0 < CG4 / CT5 < 1 When Equation 27 is satisfied, the effective diameter of the fifth lens 105 can be adjusted, and the aberration characteristics can be improved in the central and peripheral portions of the image sensor 151. Preferably, 0.3 < CG4 / CT5 < 1 can be satisfied.

[0131] [Equation 28] 0 < |L5R2| / CT5 < 5 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 lens 105 can be controlled to improve the optical performance.

[0132] [Equation 29] 0 < |L5R2| / L5R1 < 5 L5R1 is the radius of curvature of the object side surface of the fifth lens. When Equation 29 is satisfied, the refractive power of the fifth lens 105 can be controlled to improve the optical performance.

[0133] [Equation 30] 0 < L1R1 / L1R2 < 5 L1R1 is the radius of curvature of the object side surface of the first lens, and L1R2 is the radius of curvature of the sensor side surface of the first lens. When Equation 30 is satisfied, the refractive power of the first lens 101 can be controlled to improve the optical performance.

[0134] [Equation 31] 500 < |L2R1| / L2R2 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 lens 102 can be controlled to improve the optical performance, and the effective diameter of the sensor side lens of the second lens 102 can be adjusted. When the object side surface of the second lens 112 is made flat, the lens processing becomes easy.

[0135] [Equation 32] 0 < CT_Max / CG_Max < 2 In Equation 32, the maximum center thickness CT_Max of the lens and the maximum interval CG_Max between adjacent lenses can be set. When Equation 32 is satisfied, the optical system can have good optical performance at the focal length of the set angle of view, and the TTL can be reduced. Preferably, 0 < CT_Max / CG_Max < 1 can be satisfied.

[0136] [Equation 33] 0 < ΣCT / ΣCG < 2 ΣCT is the sum of the center thicknesses of the lenses, and ΣCG is the sum of the spacings between adjacent lenses. If Equation 33 is satisfied, the optical system can have good optical performance at a set angle of view and focal length, and can reduce TTL. Preferably, 0<ΣCT / ΣCG<1 can be satisfied.

[0137] [Formula 34] 5<ΣIndex<15 ΣIndex means the sum of the refractive indices of each of the multiple lenses at their d-lines. When Formula 34 is satisfied, TTL can be controlled in the optical system 100, which combines aspherical lenses and lenses made of spherical materials, and improved resolving power can be achieved. Also, when the number of lenses made of spherical materials is greater than the number of lenses made of aspherical materials, TTL and the sum of the refractive indices can be set. Formula 34 preferably satisfies 7<ΣIndex<13.

[0138] [Formula 35] 10<ΣAbbe / ΣIndex<50 ΣAbb / ΣIndex is the sum of the Abbe numbers of the lenses. When Formula 35 is satisfied, the optical system 100 can have improved aberration characteristics and resolving power. Formula 35 can be used to control the optical characteristics by setting the sum of the Abbe numbers and the sum of the refractive indices of the lenses, and preferably satisfies 10<ΣAbb / ΣIndex<30.

[0139] [Formula 36] 50<ΣCT×n<150 ΣCT is the sum of the center thicknesses of multiple lenses, and n is the number of lenses in the optical system. When Equation 36 is satisfied, TTL control is possible. Preferably, 70<ΣCT×n<120 is satisfied.

[0140] [Formula 37] 0<ΣCT / ΣET<2 ΣCT is the sum of the central thicknesses of the lenses, and ΣET is the sum of the thicknesses at the ends of the effective regions of the lenses, i.e., the edge thicknesses. When Equation 37 is satisfied, the optical system can have good optical performance at a set angle of view and focal length, and the TTL can be reduced. Equation 37 can preferably satisfy 0.5 < ΣCT / ΣET < 1.5.

[0141] [Equation 38] 1 < CA11 / CA_Min < 5 CA11 is the effective diameter of the first surface S1 on the object side of the first lens, and CA_Min indicates the minimum effective diameter among the object side surface and the sensor side surface of the lens. When Equation 38 is satisfied, the optical system can control the incident light, maintain the optical performance, and provide a more slender module. Equation 38 can preferably satisfy 1 < CA11 / CA_Min < 3. Here, CA11 may be the maximum effective diameter, and the sensor side surface of the second lens 102 may be the minimum effective diameter.

[0142] [Equation 38-1] 1 < CA_Max / CA_Min < 5 CA_Max indicates the maximum effective diameter among the object side surface and the sensor side surface of the lens. When Equation 39 is satisfied, the optical system can maintain the optical performance and set the size for a slender and compact structure. Equation 39 can preferably satisfy 1 < CA_Max / CA_Min < 3.

[0143] [Equation 39] 0 < CG2 / CA12 < 2 CG2 is the center-to-center distance between the second and third lenses, and CA12 is the effective diameter of the sensor side surface of the first lens. When Equation 39 is satisfied, the incident light of the spherical lens can be adjusted. Equation 39 can preferably satisfy 0.5 < CG2 / CA12 < 1.

[0144] [Equation 40] 1 < CA_Max / CA_Aver < 3 CA_Aver represents the average of the effective diameters on the object side and the sensor side of the lens. When Equation 40 is satisfied, the optical system can maintain optical performance and set a slim and compact sensor device. Equation 40 can preferably satisfy 1 < CA_Max / CA_Aver < 2.

[0145] [Equation 41] 0.1 < CA_Min / CA_Aver < 2 When Equation 41 is satisfied, the optical system can maintain optical performance and set a slim and compact sensor device. Equation 41 can preferably satisfy 0.5 < CA_Min / CA_Aver < 1.

[0146] [Equation 42] 1 < CA_Max / (2 × ImgH) < 6 Equation 42 can be set with the maximum effective diameter CA_Max and the diagonal length of the image sensor (2 × ImgH). When this is satisfied, the optical system can maintain good optical performance and set a slim and compact sensor device. Equation 42 can preferably satisfy 3 < CA_Max / (2 × ImgH) < 4.5.

[0147] [Equation 42-1] 1 < TD / CA_Max < 4 TD is the optical axis distance from the center of the object side of the first lens to the center of the sensor side of the last lens. When Equation 42-1 is satisfied, the overall optical axis distance and the maximum effective diameter of the lens can be set, and the size for good optical performance can be set. Equation 42-1 can preferably satisfy 1 < TD / CA_Max < 3.

[0148] [Equation 42-2] SD < TD The SD is the optical axis distance from the position of the aperture to the surface of the image sensor. Preferably, the condition 1.5 < TD / SD < 2.5 can be satisfied.

[0149] [Equation 43] 0 < F / |L5R2| < 1 F is the effective focal length of the optical system, and L5S2 is the radius of curvature of the sensor side surface of the fifth lens. When Equation 43 is satisfied, the effective focal length and the radius of curvature of the sensor side surface of the last aspherical lens can be set to adjust the influence on the reduction of the optical system, for example, TTL. Equation 43 can preferably satisfy 0 < F / |L5R2| < 0.5.

[0150] [Equation 44] 0 < F / L1R1 < 1 By setting the effective focal length of the optical system and the radius of curvature of the object side surface of the first lens in Equation 44, the influence on the incident light and TTL can be adjusted. Equation 44 can preferably satisfy 0 < F / L1R1 < 0.5.

[0151] [Equation 45] 0 < EPD / |L5R2| < 1 EPD means the size (mm) of the entrance pupil of the optical system 100, and L5R2 means the radius of curvature of the sensor side surface of the fifth lens. When the optical system 100 according to the embodiment satisfies Equation 45, the optical system 100 can control the incident light. Preferably, the condition of 0 < EPD / |L5R2| < 0.5 can be satisfied.

[0152] [Equation 46] 0 < EPD / L1R1 < 1 The size of the entrance pupil of the optical system 100 and the radius of curvature of the object side surface of the first lens can be set by Equation 46. When this is satisfied, the optical system 100 can control the incident light. Preferably, the condition of 0 < EPD / L1R1 < 0.5 can be satisfied.

[0153] [Equation 47] 0 < |F1 / F2| < 10 F1 is the focal length of the first lens, and F2 is the focal length of the second lens. When Formula 47 is satisfied, the refractive powers of the first and second lenses can be controlled to improve the resolving power and affect the TTL and effective focal length EFL. Preferably, 0<|F1 / F2|<2 can be satisfied.

[0154] [Formula 48] 0<|F1| / F<10 The focal length of the first lens and the effective focal length of the optical system can be set by using Equation 48, and the refractive power of the first lens can be controlled to improve the resolving power.

[0155] [Formula 49] 0<|F1 / F5|<10 The focal lengths of the first and fifth lenses can be set by Formula 49, and the refraction power of the first and fifth lenses can be controlled to improve the resolution. Preferably, 0<|F1 / F5|<5 can be satisfied.

[0156] [Formula 49-1] |F1| <F4

[0157] [Formula 49-2] F3 <F4

[0158] [Formula 49-3] 2×|F2| <F4 In Formulas 49-1 to 49-3, F1, F2, F3, F4, and F5 are the focal lengths of the first to fifth lenses. Light can be guided to the effective area of ​​the aspherical lens by adjusting the focal length of the last aspherical lens from the focal length of the spherical lens. Here, F1 is -10 mm or less, e.g., in the range of -10 mm to -30 mm. F2 is -5 mm or less, e.g., in the range of -5 mm to -20 mm. F3 is 15 mm or more, e.g., in the range of 15 mm to 30 mm. F4 is 16 mm or more, e.g., in the range of 16 mm to 34 mm. F5 is 5 mm or more, e.g., in the range of 5 mm to 17 mm. Balancing the focal lengths of the lenses can reduce differences in focus position due to temperature changes. This can prevent degradation of the optical characteristics of the imaging lens due to temperature changes. The aperture ST is located on the sensor side of the third lens 103. The focal length of the lens closest to the aperture ST, which is located closer to the sensor than the aperture ST, is greater than zero. In this embodiment of the present invention, the focal length F3 of the third lens 103 must be designed to be greater than 0. In this case, the third lens 103 collects light, and the effective diameters of the fourth and fifth lenses, which are lenses arranged closer to the sensor than the third lens 103, can be prevented from becoming large, the TTL can be prevented from becoming long, and the receiving optical system can be made compact. In this case, a wide-angle optical system with an FOV exceeding 100 degrees, for example, in the range of 110 degrees to 130 degrees, can be provided.

[0159] [Formula 50] Po2×Po3<0 Po2 is the refractive power value of the second lens, and Po3 is the refractive power value of the third lens. That is, the refractive powers of the second and third lenses are opposite to each other, so aberrations can be improved and the aspherical lens can effectively guide light. When Po2 × Po3 > 0, the effect of improving chromatic aberrations in both lenses is minimal.

[0160] [Formula 51] 20mm <TTL<60mm TTL (Total track length) means the distance (mm) on the optical axis OA from the center of the first surface S1 of the first lens 101 to the upper surface of the image sensor 151. By setting TTL to exceed 20 mm and be less than 60 mm in Equation 51, an optical system for a vehicle can be provided. Equation 51 can preferably satisfy 30 mm < TTL < 55 mm or can satisfy the condition of TD < TTL.

[0161] [Equation 52] 2 mm < ImgH < 20 mm Equation 52 can set the diagonal size of the image sensor 151 and can provide an optical system having the size of a vehicle sensor. Equation 52 can preferably satisfy 2 mm < ImgH < 5 mm.

[0162] [Equation 53] 1.5 mm < BFL < 7 mm In Equation 53, by setting BFL (Back focal length) to exceed 1.5 mm and be less than 7 mm, the installation space for the cover glass 153 can be secured, the assembly property of components can be improved by the interval between the image sensor 151 and the last lens, and the bonding reliability can be improved. Equation 53 can preferably satisfy 4 mm < BFL < 7 mm. When the BFL is less than the range of Equation 53, some light traveling to the image sensor may not be transmitted to the image sensor, which may cause a decrease in resolution. When the BFL exceeds the range of Equation 53, stray light may flow in and the aberration characteristics of the optical system may deteriorate.

[0163] [Equation 54] 1 mm < F < 10 mm Equation 54 can set the overall focal length F to suit the optical system for a vehicle. Equation 54 can satisfy 1 < F < 5.

[0164] [Equation 55] 100 degrees < FOV In Equation 55, FOV (Field of view) means the angular field (Degree) of the optical system 100, and an optical system for a vehicle having an angular field FOV exceeding 100 degrees can be provided. The FOV preferably satisfies 110 degrees <= (including <=, less than or equal to) FOV <= (including <=, less than or equal to) 130 degrees. The range of the optical system for a vehicle can be set by the angular field in Equation 55. The sensor length in the horizontal direction is based on 6.041 mm ± 0.5 mm. Also, when Equation 55 is satisfied, when the temperature changes from normal temperature to high temperature, the change rate of the effective focal length and the change rate of the angular field can be set to 5% or less, for example, 0 to 5%. Also, even if two or more aspherical lenses are mixed with spherical lenses in the optical system 100, the deterioration of optical characteristics can be prevented by temperature compensation and aberration correction by the aspherical lens made of glass material.

[0165] [Equation 56] 1 < TTL / CA_Max < 7 In Equation 56, CA_Max means the largest effective diameter (mm) of the object side and the sensor side of the plurality of lenses, and TTL means the distance (mm) on the optical axis OA from the vertex of the first surface S1 of the first lens to the upper surface of the image sensor 151. Equation 56 can set the relationship between the overall optical axis length and the maximum effective diameter of the optical system to provide an improved optical system for a vehicle. Equation 56 preferably satisfies 1 < TTL / CA_Max < 3.

[0166] [Equation 57] 10 < TTL / ImgH < 30 Equation 57 can set the overall optical axis length TTL of the optical system and the diagonal length ImgH in the optical axis direction of the image sensor 151. When the optical system 100 according to the embodiment satisfies Equation 57, the optical system 100 can have a TTL for the application of the vehicle image sensor 151 and can provide a more improved image quality. Equation 57 preferably satisfies 10 < TTL / ImgH < 20.

[0167] [Equation 58] 0 < BFL / ImgH < 3 Equation 58 can set the optical axis distance between the image sensor 151 and the last lens and the length in the diagonal direction along the optical axis of the image sensor 151. When the optical system 100 according to the embodiment satisfies Equation 58, the optical system 100 can secure a BFL for applying the size of the vehicle image sensor 151, can set the distance between the last lens and the image sensor 151, and can have good optical characteristics at the center and periphery of the angle of view FOV. Equation 58 can preferably satisfy 1.5 < BFL / ImgH < 2.5.

[0168] [Equation 58-1] ImgH < BFL < D1 BFL is the optical axis distance from the sensor side surface of the nth lens or the fifth lens 105 to the image sensor 151, and can be larger than a value (ImgH) that is 1 / 2 of the diagonal length of the image sensor 151, and can also be smaller than the optical axis distance from the optical filter 155 to the surface of the image sensor 151.

[0169] [Equation 59] 5 < TTL / BFL < 20 Equation 59 can set the overall optical axis length TTL of the optical system and the optical axis distance BFL between the image sensor 151 and the last lens. When the optical system 100 according to the embodiment satisfies Equation 59, the optical system 100 can secure a BFL. Equation 59 can preferably satisfy 5 < TTL / BFL < 12.

[0170] [Equation 60] 10 < TTL / F < |30 Equation 60 can set the overall focal length F and the overall optical axis length TTL of the optical system 100. Thereby, an optical system for a driver assistance system can be provided. Equation 60 can preferably satisfy 10 <= (including <=, less than or equal to) TTL / F < 25 or 12 < TTL / F < 20. When the optical system 100 according to the embodiment satisfies Equation 60, the optical system 100 can have an appropriate focal length within the set TTL range, maintain an appropriate focal length even when the temperature changes from low to high, and provide an optical system capable of imaging. If it is less than the lower limit value of Equation 60, it is necessary to increase the refractive power of the lens, and it becomes difficult to correct spherical aberration or distortion aberration. If it exceeds the upper limit value of Equation 60, problems such as an increase in the effective diameter and TTL of the lens and an increase in the size of the imaging lens system may occur.

[0171] [Equation 61] 0 < F / BFL < 3 Equation 61 can set the overall focal length F of the optical system 100 and the optical axis interval BFL between the image sensor 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 angle of view, can have an appropriate focal length, and can provide an optical system for a vehicle. Also, the optical system 100 can minimize the interval between the last lens and the image sensor 151 and can have good optical characteristics at the peripheral part of the angle of view FOV. Equation 61 can preferably satisfy 0 < F / BFL < 1.

[0172] [Equation 62] 0.5 < F / ImgH < 1.5 Equation 62 can set the overall focal length F of the optical system 100 and the diagonal length ImgH on the optical axis of the image sensor 151. Such an optical system 100 can have improved aberration characteristics in the size of the vehicle image sensor 151. Equation 62 can preferably satisfy 0.7 < F / ImgH < 1.

[0173] [Equation 63] 0.5 < F / EPD < 1.5 Equation 63 can set the overall focal length F of the optical system 100 and the size of the entrance pupil. Thereby, the overall brightness of the optical system can be controlled. Equation 63 can preferably satisfy 0.5 < F / EPD < 1.

[0174] [Equation 64] 0 < EPD / ImgH / FOV < 0.2 Equation 64 can set the relationship between the size EPD of the entrance pupil, the length ImgH which is half of the maximum diagonal length of the image sensor, and the angle of view. Thereby, the overall size and brightness of the optical system can be controlled. Equation 64 can preferably satisfy 0 < EPD / ImgH / FOV < 0.1.

[0175] [Equation 65] 100 < FOV / F# < 200 Equation 65 can set the relationship between the angle of view of the optical system and the F-number F#. Equation 65 can preferably satisfy 120 < FOV / F# < 170. Here, F# can be provided to be 1.2 or less to provide a bright image.

[0176] [Equation 66] 50 < (CT_Max + CG_Max) × n < 150

[0177] [Equation 67] 800 < (FOV × TTL) / n Preferably, Equation 67 can satisfy the condition of 1000 < (FOV × TTL) / n < 1500 according to the angle of view and the number of lenses n.

[0178] [Equation 68] FOV < (TTL × n)

[0179] [Equation 69] 1 < (TD / CA_Max) × n < 20 Preferably, it can satisfy 5 < (TD / CA_Max) × n < 15.

[0180] [Equation 70] 0<(CA52 / CA22) / (CA11 / CA22)<1 In Expressions 66 to 70, n is the total number of lenses, and depending on the total number of lenses n, it is possible to set relationships with the maximum center-to-center thickness CT_Max of the lenses, the maximum center-to-center spacing CG_Max, FOV, TTL, the optical axis distance TD of the lenses, the effective diameter CA52 of the fifth lens on the sensor side, the effective diameter of the first lens on the object side, the effective diameter of the second lens on the sensor side, etc. This makes it possible to control the chromatic aberration, resolving power, size, etc. of an optical system having six or fewer lenses.

[0181] [Formula 71] JPEG2025534649000005.jpg16140In Equation 71, Z represents Sag and may represent the distance in the optical axis direction from an arbitrary position on the aspheric surface to the apex of the aspheric surface. Y may represent the distance in a direction perpendicular to the optical axis from an arbitrary position on the aspheric surface to the optical axis. c may represent the curvature of the lens, and K may represent the Conic constant. Additionally, A, B, C, D, E, and F may represent aspheric constants.

[0182] The optical system 100 according to the embodiment may satisfy at least one or two or more of Equations 1 to 70. In this case, the optical system 100 may have improved optical characteristics. Specifically, when the optical system 100 satisfies at least one of Equations 1 to 35 and / or at least one of Equations 36 to 70, the optical system 100 may have improved resolving power and improved aberration and distortion characteristics. In addition, the optical system 100 may ensure a BFL for applying the vehicle image sensor 151, compensate for deterioration of optical characteristics due to temperature changes, minimize the distance between the last lens and the image sensor 151, and have good optical performance in the center and periphery of the field of view (FOV).

[0183] Table 4 relates to the items in the above-mentioned formulas for the optical system 100 of the embodiment, such as TTL (mm), BFL, effective focal length F, ImgH, effective diameter CA, sum of center thicknesses of each lens, sum of center spacings between adjacent lenses, TTL (mm), sum of Abbe numbers, sum of refractive indexes, TD (mm) which is the optical axial distance from the first surface S1 to the tenth surface S10, focal lengths F1, F2, F3, F4, F5 of the first to fifth lenses, angle of view FOV, edge thickness ET, F-number, etc. [Table 4]

[0184] Table 5 shows the results of the above-mentioned formulas 1 to 35 in the optical system 100 of the example. Referring to Table 5, it can be seen that the optical system 100 satisfies at least one, two or more, or three or more of formulas 1 to 50. More specifically, it can be seen that the optical system 100 of the example satisfies all of formulas 1 to 50. As a result, the optical system 100 can have good optical performance in the center and periphery of the field of view FOV, and can have excellent optical characteristics. [Table 5] TIFF2025534649000008.tif183135

[0185] Table 6 shows the results of the above-mentioned formulas 36 to 70 in the optical system 100 of the example. Referring to Table 6, it can be seen that the optical system 100 satisfies at least one, two or more, or three or more of formulas 36 to 70. In particular, it can be seen that the optical system 100 of the example satisfies all of formulas 1 to 70. As a result, the optical system 100 can have good optical performance in the center and periphery of the field of view FOV, and can have excellent optical characteristics. [Table 6] TIFF2025534649000010.tif81141

[0186] FIG. 10 is a cross-sectional side view showing the transmission optical system of the present invention.

[0187] Referring to FIG. 10, the transmitting optical system 110 and a sensor system including the transmitting optical system 110 can be mounted inside or outside a vehicle and transmit a laser beam to monitor the driver or to an external object or lane. The receiving optical system can sense the reflected laser beam. The material of the lens in the transmitting optical system 110 can be selected from glass or plastic. For example, a glass lens can be selected to suppress changes in the focal position due to temperature changes. However, most glass lenses are provided with a spherical surface, and when an optical system is constructed using spherical glass lenses, there is a limit to how many lenses can be reduced, which limits the size and weight reduction.

[0188] The transmission optical system 110 according to an embodiment of the present invention may include a spherical lens and an aspherical lens. The transmission optical system 110 may include a spherical glass lens and an aspherical glass lens. Furthermore, by using an aspherical lens, the overall length TTL of the optical system 110 is reduced, and the aspherical lens enables favorable correction of various aberrations, such as spherical aberration and chromatic aberration. Furthermore, the aspherical lens can minimize peripheral distortion. The transmission optical system 110 may include n lenses, where the nth lens may be the last lens adjacent to the light source 116, and the (n-1)th lens may be the lens closest to the last lens. The 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 in the n lenses may be any one of 3:1, 4:1, 3:2, 2:3, 3:3, 5:2, and 4:2.

[0189] The first lens 111 of the transmitting optical system 110 may be made of a glass lens. The glass material has little expansion and contraction due to changes in external temperature and has a scratch-resistant surface, which can prevent surface damage. Therefore, the object-side lens of the optical system 110 may be a spherical lens, and the light-source-side lens may be an aspherical lens.

[0190] At least one lens adjacent to the light source 116 in the optical system 110 may be an aspherical lens. For example, at least two lenses adjacent to the light source 116 may be aspherical lenses, and preferably at least two lenses adjacent to the light source 116 may be aspherical lenses. That is, since the nth and n-1th lenses in the optical system 110 are aspherical lenses, light emitted from the light source 116 can be emitted along various paths. At least two lenses adjacent to the object in the transmitting optical system 110 may be made of glass. Two or more lenses adjacent to the object, for example, two to four lenses, may be made of glass. Since glass lenses have a smaller rate of contraction and expansion due to temperature changes than plastic lenses, glass lenses may be disposed in a region adjacent to the exterior within the lens barrel.

[0191] Each lens may have an object side surface and a light source side surface. The lenses may include an object side spherical lens, a light source side spherical lens, and an object side aspherical lens, and a light source side aspherical lens. The optical system may have a smaller number of aspherical lenses than spherical lenses. The transmitting optical system 110 may provide variously refracted light by arranging an aspherical lens adjacent to the light source 116. The spherical lens may be made of glass, and the aspherical lens may be made of molded glass.

[0192] The lens having the highest refractive index among the lenses in the optical system 110 may be a spherical lens, and the lens having the highest Abbe number may be a spherical lens. As a result, since the lens having the highest refractive index is disposed closer to the object side, it is easy to change the radius of curvature of the second and subsequent lenses, and the center thickness can be increased.

[0193] The lens having the largest effective diameter in the optical system 110 is located closest to the object and may be a glass lens and a spherical lens. The lens having the smallest effective diameter in the optical system 110 is located between the aperture stop ST and the first lens 111 and may be a glass lens. The average effective diameter of the aspherical lenses may be smaller than the average effective diameter of the spherical lenses. Here, the effective diameter of the lenses is the average of the effective diameter of the object-side surface and the effective diameter of the light source-side surface of each lens. Each of the lenses 111-115 may include an effective area and a non-effective area.

[0194] Among the lenses of the optical system 110, the lens having the greatest center thickness may be an aspherical lens, and the lens having the greatest edge thickness may be an aspherical lens. This allows for a variety of refractive surfaces to be provided, improving optical performance even to the periphery. The center thickness of the aspherical lens may be greater than the center thickness of the spherical lens. Such an aspherical lens is disposed adjacent to the light source 116, allowing the laser light to be refracted to the entire area of ​​the object-side lens.

[0195] In the optical system 110, TTL may be 10 times greater than LsH, for example, 10 times greater and 20 times less than LsH. TTL is the distance on the optical axis Lz from the center of the object side of the first lens 111 to the top surface of the light source 116. LsH is the distance from the center of the light source 116 to the diagonal end, or 1 / 2 the maximum diagonal length of the light source 116. Furthermore, the effective diameter of each lens in the optical system 110 may be greater than the diagonal length of the light source 116. The optical system 110 may have an effective focal length EFL of 10 mm or less and an angle of view FOV of more than 100 degrees or 120±10 degrees, which can be used as a standard transmission optical system in a vehicle sensor system. For example, the transmission optical system and sensor system according to the embodiment can be applied to a sensing device for an ADAS (Advanced Driving Assistance System) installed inside or outside a vehicle. Here, the TTL of the receiving optical system in FIG. 1 may be defined as a first TTL, and the TTL of the transmitting optical system may be defined as a second TTL. Furthermore, the optical axis of the receiving optical system may be the first optical axis, and the optical axis Lz of the receiving optical system may be the second optical axis.

[0196] The optical system 110 may have a TTL / (2×LsH) condition of 5 or more, for example, in the range of 5 to 10. This allows the central thickness of each lens along the optical axis Lz to be increased, thereby reducing the size of the light source 116 and providing a lens optical system for a vehicle. Furthermore, since the optical system 110 is used in a vehicle camera, it must be temperature-compensated within the temperature range of -40°C to +120°C, which is the temperature reliability evaluation standard for automotive electrical components. That is, the lens must be configured so that the lens focus remains within a set range even when the lens expands or contracts due to temperature changes. The total effective focal length EFL may be 10 mm or less, for example, in the range of 1 mm to 10 mm or 1 mm to 5 mm, and the lens may be made of a glass material capable of temperature compensation. The optical system 110 can achieve a wide angle by shortening the effective focal length.

[0197] The number of lenses having positive (+) refractive power in the optical system 110 may be equal to or greater than the number of lenses having negative (-) refractive power. The number of lenses having positive (+) refractive power may be 50% or more of the total number of lenses. The average refractive index of the lenses having negative refractive power may be greater than the average refractive index of the lenses having positive refractive power. As a result, the dispersion value of the lenses having positive refractive power may be greater than the dispersion value of the lenses having negative refractive power. Since the optical system 110 includes a combination of spherical and aspherical lenses made of glass, deterioration of optical performance can be prevented. The effective diameter of the lens closest to the object in the optical system 110 may be greater than the effective diameter of the lens closest to the light source 116. This allows the brightness of the optical system to be controlled. By controlling the effective diameter of each lens, the optical system 110 can control the incident light to compensate for deterioration of optical characteristics due to resolving power and temperature changes, and improve chromatic aberration control characteristics. By adjusting the effective diameter of the lens, the optical system 110 can be made smaller.

[0198] The transmission optical system 110 may include a first lens 111 to a fifth lens 115 aligned from the object side toward the light source side along the optical axis Lz. The first to fifth lenses 111, 112, 113, 114, and 115 may be defined as a lens unit. A light source 116 generates a laser beam, which may have a wavelength in the range of 890 nm to 960 nm or 940 nm ±10 nm. The first lens 111 of the transmission optical system 110 may correspond in shape to the first lens 101 of the reception optical system 100 of FIG. 1. The second lens 112 of the transmission optical system 110 may correspond in shape to the second lens 102 of the reception optical system 100 of FIG. 1. The third lens 113 of the transmission optical system 110 may correspond in shape to the third lens 103 of the reception optical system 100 of FIG. 1. The fourth lens 114 of the transmission optical system 110 may correspond in shape to the fourth lens 104 or the first aspherical lens of the reception optical system 100 of FIG. 1. The fifth lens 115 of the transmitting optical system 110 may have a shape corresponding to the first lens 105 or the second aspherical lens of the receiving optical system 100 of FIG.

[0199] In terms of the radius of curvature in absolute terms, the lens surface having the smallest radius of curvature relative to the optical axis Lz in the optical system 110 may be the light source side surface of the first or second lens 111 or 112 among the spherical surfaces. This allows for the distance between the centers of the first lens 111 and the second lens 112 or the distance between the centers of the second lens 112 and the third lens 113 to be increased. The lens surface having the largest radius of curvature in the optical system 110 may be the object side surface of the second lens 114 among the spherical surfaces. By adjusting the radius of curvature of each lens, the chief ray angle (CRA) can be minimized to 0.5 degrees or less from the optical axis to the end of the effective area, i.e., across the entire field, thereby maximizing transmission efficiency. Here, as the CRA increases, the asymmetry of the divergence angle relative to the center of the light source 116 in the transmission optical system 110 increases, thereby reducing transmission efficiency.

[0200] The transmission optical system 110 or the sensor system may include a light source 116. The light source 116 generates laser light having a wavelength in the range of 890 nm to 960 nm or 940 nm ±10 nm. The light source 116 may be implemented as an InGaAs / GaAs-based semiconductor diode laser and may emit high-power laser light. The light source 116 may include a single emitter and / or multiple emitters. The light source 116 generates laser light in the form of a line light source or a point light source. Here, the length of the light source 116 is the maximum length in a diagonal direction perpendicular to the optical axis Lz. Here, the number of lenses having an effective diameter larger than the length of the light source 116 is four to six, and the number of lenses having an effective diameter smaller than the length of the light source 116 may be zero.

[0201] The transmitting optical system 110 may include a stop ST. The stop ST can adjust the amount of light emitted from the transmitting optical system 110. The stop ST may be disposed around the third lens 113 and the fourth lens 114. The stop ST is disposed between the spherical third lens 113 and the aspherical fourth lens 114. The stop ST is disposed between the light source side spherical surface of the third lens 113 and the object side aspherical surface of the fourth lens 114. Here, the stop of the receiving optical system 100 referred to in the drawings can be defined as a first stop, and the stop of the transmitting optical system 110 can be defined as a second stop.

[0202] At least two lenses are disposed between the aperture ST and the light source 116. For example, the fourth and fifth lenses 114 and 115 are disposed between the aperture ST and the light source 116. An aspherical lens is disposed between the aperture ST and the light source 116. The aperture ST is disposed between the light source side spherical surface of the third lens 113 and the object side aspherical surface of the fourth lens 114.

[0203] In a lens disposed between the object and the aperture stop ST, the effective diameter of the lens surface tends to increase from the second lens 112 toward the aperture stop ST. In a lens surface disposed between the aperture stop ST and the light source 116, the effective diameter of the lens surface tends to decrease from the aperture stop ST toward the light source 116. The term "the effective diameter of the lens surface tends to increase or decrease" does not only mean that the effective diameter of the lens surface increases or decreases. For example, it also includes a case where the effective diameter of the lens surface decreases as it increases from the aperture stop ST toward the light source.

[0204] The lens surface on which the aperture ST is disposed is intended to more efficiently adjust and guide the amount of light in the optical system 110. As in the embodiment, the aperture ST may be disposed on the light source side of the third lens 113. Alternatively, the aperture ST may be disposed around the object side or light source side of the second lens 112. Alternatively, at least one lens selected from the plurality of lenses, for example, the object side or light source side of the third lens 113, may function as the aperture. The aperture ST may be eliminated in the transmission optical system 110.

[0205] In the optical system 110 according to the embodiment, the sum of the refractive indexes of the lenses in the lens section may be 8 or more, for example, in the range of 8 to 12, and the average of the refractive indexes may be in the range of 1.70 to 1.80. The sum of the Abbe numbers of the lenses may be 200 or less, for example, in the range of 130 to 200, and the average of the Abbe numbers may be 50 or less, for example, in the range of 25 to 50. By adjusting the refractive index of the lenses in the optical system 100, it is possible to prevent a decrease in transmission efficiency due to temperature changes from -45 to 120 degrees and optimize thermal compensation. In addition, it is possible to minimize deviations in transmission efficiency according to wavelength by adjusting the Abbe numbers of the lenses.

[0206] The sum of the center thicknesses of all the lenses may be 15 mm or more, for example, in the range of 15 mm to 25 mm, and the average center thickness may be 3.9 mm or less, for example, in the range of 2.9 mm to 3.9 mm. The sum of the center distances between the lenses on the optical axis Lz may be 15 mm or more, for example, in the range of 15 mm to 30 mm, which is greater than the sum of the center thicknesses of the lenses. In addition, the average effective diameter of each lens surface of the optical system 110 may be 20 mm or less, for example, in the range of 10 mm to 20 mm. The optical system 110 can adjust the thickness of the lenses to prevent degradation of optical performance with temperature changes from -45 degrees to 120 degrees and optimize thermal compensation.

[0207] The optical system according to an embodiment of the invention may have an angle of view exceeding 100 degrees, for example, in the range of 110 to 130 degrees. The F-number of the optical system or camera module may be 1.2 or less, for example, in the range of 0.7 to 1.2 or 0.7 to 0.9. The diagonal length of the light source 116 may be 6.80 mm ± 0.5 mm, which may be greater than the vertical height of the sensor. The invention can be applied to a vehicle LiDAR device that can suppress changes in the focal position due to temperature changes by stacking glass lenses and correct various aberrations by providing aspherical lenses.

[0208] Since the embodiment is a transmission optical system applied to a LiDAR device, the first lens 111 may be made of glass. Glass has advantages over plastic in that it is scratch-resistant and less sensitive to external temperatures. A glass lens may be used as the first lens 111 to more effectively prevent scratches caused by foreign objects disposed inside the vehicle, and the object side of the first lens 111 may have a convex shape to prevent accumulation of foreign objects. The LiDAR device can detect the distance, direction, speed, temperature, and material distribution and concentration characteristics of an object while the vehicle is in operation. Such a LiDAR device can be used for an advanced driver assistance system (ADAS). The transmission optical system 110 according to the embodiment may further include a reflecting member (not shown) for changing the path of light. The reflecting member may be implemented as a prism that reflects the emitted light toward the lens. The optical system according to the embodiment will now be described in detail.

[0209] For the transmission optical system according to the embodiment of the invention, please refer to FIGS. 10 to 17. FIG.

[0210] 10 to 13, the optical system 110 may include a first lens 111 to a fifth lens 115. The first to fifth lenses 111 to 115 are sequentially arranged along an optical axis Lz of the optical system 110. A laser beam generated from the light source 116 is emitted through the fifth lens 115, the fourth lens 114, the third lens 113, the second lens 112, and the first lens 111. The aperture ST may be arranged around the light source side of the third lens 113. For convenience of explanation, the lenses of the transmission optical system are described as the first to fifth lenses, but when applied to a LiDAR device having lenses of a reception optical system, they may be defined as the sixth to tenth lenses.

[0211] The first lens 111 may have positive (+) or negative (-) refractive power along the optical axis Lz. The first lens 111 may have negative (-) refractive power. The first lens 111 may include a plastic material or a glass material, for example, a glass material. The glass first lens 111 can reduce changes in the center position and curvature radius due to temperature changes depending on the surrounding environment and can protect the exit side of the optical system 110. On the optical axis, the first surface S1 of the first lens 111 on the object side may have a convex shape, and the second surface S2 on the light source side may have a concave shape. The first surface S1 and the second surface S2 may have spherical surfaces. The first lens 111 may have a meniscus shape that bulges toward the object side. Alternatively, the first surface S1 may have a concave shape and the second surface S2 may have a convex shape along the optical axis Lz. Since the first surface S1 has a convex shape and the second surface S2 has a concave shape, the emitted light can be refracted in a direction away from the optical axis Lz, the distance between the first and second lenses 111 and 112 can be reduced, and the effective diameter of the second lens 112 can be reduced. Depending on the shape of the lens surface of the first lens 111, the effective diameter of the second lens 112 on the light source side can be designed to be smaller than the effective diameter on the object side. The first surface S1 of the first lens 111 is provided without a critical point from the optical axis Lz to the end, i.e., edge, of the effective area. The second surface S2 of the first lens 111 is provided without a critical point.

[0212] When the refractive index of the first lens 111 is n1, it can satisfy the condition of n1>1.7 or 2.0>n1>1.75. Because the refractive index n1 of the first lens 111 is higher than that of the other lenses, the radius of curvature of the first surface S1 of the first lens 111 can be increased, making it easier to manufacture the lens. If the refractive index n1 of the first lens 111 is lower than this condition, the lens surface must be formed to be sharply concave or convex in order to increase the refractive power of the first and second lenses 111 and 112, which makes lens manufacturing difficult and increases the rate of defective lenses, resulting in a decrease in yield.

[0213] The second lens 112 is disposed between the first lens 111 and the third lens 113. The second lens 112 may have positive (+) or negative (-) refractive power on the optical axis Lz. The second lens 112 may have negative (-) refractive power. The second lens 112 may include plastic or glass, for example, and may be made of glass. On the optical axis Lz, the object-side third surface S3 of the second lens 112 may be flat, and the light-source-side fourth surface S4 may be concave. The fourth surface S4 may be spherical. The fourth surface S4 is provided without a critical point from the optical axis Lz to the end of the effective area. Alternatively, the third surface S3 may be convex, and the fourth surface S4 may be concave. Alternatively, the second lens 112 may have concave surfaces on both sides.

[0214] When the refractive index of the second lens 112 is n2, the condition of n2 > 1.7 or 2.0 > n2 > 1.75 can be satisfied. Since the refractive index n2 of the second lens 112 is higher than that of other lenses, the radius of curvature of the third surface S3 of the second lens 112 can be increased, making the manufacture of the lens easier. Since the fourth surface S4 on the light source side of the second lens 112 has a concave shape and a small radius of curvature, the center distance between the second lens 112 and the third lens 113 can be separated. Also, when the radius of curvature of the third surface S3 of the second lens 112 is L2R1 and the radius of curvature of the fourth surface S4 is L2R2, the condition of L2R1 > L2R2 can be satisfied. When this condition is satisfied, the light emitted by the third and fourth surfaces S3 and S4 can be efficiently refracted so that the effective diameters of the third to fifth lenses 114 to 115 do not increase, and the TTL can be reduced. If the condition is L2R1 < L2R2, a large amount of aberration occurs on the object side surface of the second lens 112, the light refraction efficiency decreases on the light source side surface, the effective diameter of the rear lens increases, and the TTL also increases.

[0215] The third lens 113 can have a positive (+) or negative (-) refractive power with respect to the optical axis Lz. The third lens 113 may have a positive (+) refractive power. The third lens 113 can include a plastic or glass material, and for example, it may be a glass material. On the optical axis, the fifth surface S5 on the object side of the third lens 113 has a convex shape, and the sixth surface S6 on the light source side can have a convex shape. The third lens 113 can have convex shapes on both surfaces with respect to the optical axis Lz. At least one or both of the fifth surface S5 and the sixth surface S6 may be spherical surfaces. At least one or both of the fifth surface S5 and the sixth surface S6 are provided without critical points from the optical axis Lz to the end of the effective region. Alternatively, the third lens 113 can have a meniscus shape bulging on the object side or the light source side. Or, the third lens 113 can have concave shapes on both surfaces on the optical axis. When the refractive index of the third lens 113 is n3, the conditions n3 < n1 and n3 < n2 can be satisfied. When the Abbe number of the third lens 113 is v3, the conditions v3 < v1 and v3 < v2 can be satisfied.

[0216] The aperture stop ST is disposed around the sixth surface S6 on the light source side of the third lens 113. Since the third lens 113 adjacent to the object side of the aperture stop ST has a positive refractive power (F3 > 0), the third lens 113 can refract the emitted light in the optical axis direction and suppress an increase in the effective diameter of the light source side or the rear lens side of the third lens 113. Thereby, it is possible to prevent a decrease in the yield by weight of the optical system by the third lens 113 and improve the production efficiency. Here, the focal lengths of the fourth and fifth lenses 114 and 115 disposed on the light source side of the aperture stop ST can have positive values, and the TTL can be reduced within the angle-of-view range. Since the sixth surface S6 on the light source side of the third lens 113 has a convex shape, the effective diameter of the optical filter 155 disposed on the light source side of the third lens 113 may be larger than the effective diameter of the sixth surface S6 of the third lens 113.

[0217] The fourth lens 114 may have positive (+) or negative (-) refractive power on the optical axis Lz. The fourth lens 114 may have positive (+) refractive power. The fourth lens 114 may include plastic or glass, and may be made of glass. The fourth lens 114 may be injection-molded glass. The seventh object-side surface S7 of the fourth lens 114 may have a convex shape on the optical axis, and the eighth light-source-side surface S8 may have a convex shape on the optical axis. The fourth lens 114 may have convex surfaces on both sides. At least one or both of the seventh surface S7 and the eighth surface S8 may be aspherical. The aspherical coefficients of the seventh and eighth surfaces S7 and S8 may be represented by S1 and S2 of L4 in FIG. 12. The seventh surface S7 may have a critical point from the optical axis Lz to the end of the effective area. The eighth surface S8 is provided without a critical point from the optical axis Lz to the end of the effective area. Both the seventh surface S7 and the eighth surface S8 may have no critical point or a critical point. Here, the critical point may refer to a point where the sign of the slope with respect to the optical axis Lz and the direction perpendicular to the optical axis Lz changes from positive (+) to negative (-) or from negative (-) to positive (+), and the slope value becomes zero. The critical point may also be a point where the slope of a tangent passing through the lens surface decreases while increasing, or a point where the slope increases while decreasing. Alternatively, the fourth lens 114 may have a meniscus shape that bulges toward the object side or the light source side. Alternatively, the fourth lens 114 may have a concave shape on both sides of the optical axis Lz.

[0218] The fifth lens 115 may have a positive (+) or negative (-) refractive power on the optical axis Lz. The fifth lens 115 may have a positive (+) refractive power. The fifth lens 115 may include a plastic or glass material, or may be made of a glass material. The fifth lens 115 may be an injection-molded glass mold.

[0219] The ninth object-side surface S9 of the fifth lens 115 may have a convex shape on the optical axis, and the tenth light-source-side surface S10 may have a convex shape. The fifth lens 115 may have convex surfaces on both sides. At least one or both of the ninth surface S9 and the tenth surface S10 may be aspherical. The aspherical coefficients of the ninth and tenth surfaces S9 and S10 may be represented by L1 and L2 of L5 in FIG. 12. At least one of the ninth and tenth surfaces S9 and S10 may have a critical point from the optical axis Lz to the end of the effective area. Neither the ninth surface S9 nor the tenth surface S10 may have a critical point. Alternatively, the fifth lens 115 may have a meniscus shape that bulges toward the object side or the light source side. Alternatively, the fifth lens 115 may have a concave shape on both sides on the optical axis Lz. The effective diameter of the fifth lens 115 may be smaller than the effective diameter of the fourth lens 114. The fifth lens 115 may have a refractive index lower than the refractive indexes of the first and second lenses 111 and 112, and may have an Abbe number lower than the Abbe number of the first and second lenses 111 and 112.

[0220] The third lens 113, the fourth lens 114, and the fifth lens 115 may have biconvex surfaces and may all have positive refractive power. The third lens 113, the fourth lens 114, and the fifth lens 115 may have a refractive index lower than that of the first and second lenses 111 and 112, and may have an Abbe number lower than that of the first and second lenses 111 and 112. At least one of the object-side surface and the light-source-side surface of the fourth and fifth lenses 114 and 115 may have a free-form surface, i.e., a non-rotationally symmetric curved surface.

[0221] The fifth lens 115 may be an aspherical lens closest to the light source 116. By arranging two or more aspherical lenses adjacent to the light source 116, aberrations such as spherical aberration and chromatic aberration can be improved by the lens surfaces having aspherical surfaces.

[0222] When the lens having negative refractive power is in the first lens group and the lens having positive refractive power is in the second lens group, the diaphragm ST may be disposed in the second lens group. The diaphragm ST is disposed between the first lens group, at least one of whose object-side surface and light-source-side surface is spherical, and the second lens group, at least one of whose object-side surface and light-source-side surface is aspherical. The diaphragm ST is disposed between the first lens group having a lens that is not injection-molded and the second lens group having a lens that is injection-molded. The diaphragm ST is disposed between the first lens group having a lens disposed on the object side of the diaphragm ST and the second lens group having a lens disposed on the light-source side of the optical filter 155.

[0223] As shown in Figures 10 and 11, the center thicknesses of the first to fifth lenses 111 to 115 are indicated by CT1 to CT5, the edge thicknesses at the ends of the effective areas of each lens are indicated by ET1 to ET5, and the center distances between adjacent lenses are indicated by CG1 to CG4.

[0224] The first to fifth lenses 111 to 115 can satisfy the following conditions.

[0225] Condition 1: CT2 <CT1<CT3 Condition 2: CT4 <CT5<(CT3+CT4) Condition 3: CT4-CT3 <CT2 Condition 4: ET3 <ET2<ET1 Condition 5: ET4 <ET3<ET5<CT5 Condition 6: CT2 <CT1<ET2<ET1 Condition 7:CG1 <CT4<CT5<CG2 Condition 8:CG3 <CT1<CG4<CG1 The center thickness CT5 of the fifth lens 115 is the largest among the lenses, and the center thickness CT2 of the second lens 112 is the smallest among the lenses. The maximum center thickness may be at least two times, for example, three times, the minimum center thickness, and the difference between the maximum and minimum center thicknesses may be at least 4 mm. In other words, even if a lens made of a spherical material has a thin center thickness, the optical performance does not deteriorate and the thickness of the sensor system can be slimmed down.

[0226] Regarding the center distance CG between adjacent lenses, the center distance CG2 between the second lens 112 and the third lens 113 is the largest and is larger than the center distance CG1 between the first and second lenses 111 and 112. The center distance CG3 between the third and fourth lenses 113 and 114 is the smallest among the lens distances. Here, the difference between the maximum center distance and the minimum center distance may be 5 mm or more, for example, in the range of 5 mm to 8 mm. In addition, by providing the maximum center distance between lenses larger than the maximum center thickness of each lens, a transmission optical system can be provided that does not increase the center distance between aspherical lenses. In addition, since the maximum center distance between lenses is larger than the minimum center thickness of each lens, the optical path can be controlled.

[0227] Regarding the effective diameter, the lens having the largest effective diameter may be the first lens 111 closest to the object. The lens having the largest effective diameter may be a spherical lens made of glass. The lens surface having the largest effective diameter may be the first surface S1 of the first lens 111. The lens having the smallest effective diameter may be the second lens 112 adjacent to the first lens 111. The lens surface having the smallest effective diameter may be the fourth surface S4 of the second lens 112, and may be less than 70% of the first surface S1. The effective diameter of each of the first to fifth lenses 111-115 may be greater than the diagonal length of the light source 116. Here, the sum of the central thicknesses of the first to third lenses 111-113 may be smaller than the sum of the central thicknesses of the fourth and fifth lenses 114 and 115. The average effective diameter of the first to third lenses 111-113 may be greater than the average effective diameter of the fourth and fifth lenses 114 and 115. The fourth and fifth lenses 114 and 115 have aspherical surfaces and can guide the incident light to the spherical lenses.

[0228] Fig. 11 shows an example of lens data for the optical system of the embodiment shown in Fig. 10. As shown in Fig. 11, the radius of curvature of the first to fifth lenses 111, 112, 113, 114, and 115 on the optical axis Lz, the center thickness CT of the lenses, the center spacing CG between the lenses, the refractive index at the d-line, the Abbe number, and the effective radius can be set.

[0229] 12, the lens surfaces of the fourth and fifth lenses 114 and 115 of the embodiment may include aspherical surfaces having aspherical coefficients A, B, C, D, and E of 12th order or higher, where Y is the radius of curvature and K is the Conic constant. For example, the object-side and light-source-side surfaces of the fourth and fifth lenses 114 and 115 may have aspherical coefficients of 12th order or higher, for example, 30th order.

[0230] The focal lengths F1 and F2 of the first and second lenses 111 and 112 may have negative refractive power, and the focal lengths F3, F4 and F5 of the third, fourth and fifth lenses 113, 114 and 115 may have positive refractive power. In addition, the second lens 112 and the third lens 113, which are adjacent lenses, may satisfy the following condition:

[0231] Condition 1: Refractive index of lens with positive refractive power < Refractive index of lens with negative refractive power Condition 2: Dispersion value of a lens with positive refractive power > Dispersion value of a lens with negative refractive power Here, the second lens 112 of the lenses has negative refractive power, and the third lens 113 has positive refractive power. Therefore, according to conditions 1 and 2, the refractive index of the third lens is smaller than that of the second lens, and the dispersion value of the third lens is larger than that of the second lens. Chromatic aberration occurring in a spherical lens can be corrected by the spherical lens. Furthermore, the difference in refractive index between the second lens 112 and the third lens 113, which are consecutively arranged spherical lenses, can satisfy the following: 0.1 to 0.15, and the difference in Abbe number can satisfy the following: 10 to 20.

[0232] As temperatures change from low to high, lenses repeatedly contract and expand. Lenses made of the same material experience the same amount of change in lens characteristics due to temperature changes, so it is effective to correct chromatic aberration between lenses made of the same material even when the temperature changes. For example, as shown in FIG. 13, when the temperature of the lens barrel or transmitting optical system changes from -40 degrees to 90 degrees, the refractive indexes of the first to fourth lenses at the d-line remain almost unchanged. Therefore, in this embodiment of the invention, the fourth lens 114 and the fifth lens 115 can correct chromatic aberration that occurs in spherical lenses made of glass.

[0233] When comparing the focal lengths in absolute values, the focal length of the fourth lens 114 is the longest among the lenses, and may be greater than or equal to 20 and less than or equal to 40. This allows the optical system to have improved MTF characteristics, aberration control characteristics, and the like within the angle of view range set by the optical system, thereby providing good optical performance.

[0234] Figure 14 is a graph showing the diffraction MTF at low, room, and high temperatures for the optical system of Figure 10, illustrating the luminance modulation as a function of spatial frequency. As shown in Figure 14, in an embodiment of the invention, the deviation of the MTF at low or high temperatures from room temperature can be less than 10%, i.e., 7% or less. Here, each MTF curve was measured in 0.340mm increments from 0.000mm to 3.550mm.

[0235] 15 to 17 are graphs showing the aberration characteristics of the optical system of FIG. 10 at low, room, and high temperatures. The aberration graphs of FIGS. 15 to 17 are graphs in which spherical aberration, astigmatic field curves, and distortion are measured from left to right. In FIGS. 15 to 17, the X-axis represents focal length (mm) and distortion (%), and the Y-axis represents image height. The spherical aberration graphs are for light in wavelength bands of approximately 930 nm, 940 nm, and 950 nm, while the astigmatic and distortion graphs are for light in a wavelength band of approximately 940 nm. In the aberration graphs of FIGS. 15 to 17, the closer the curves at low, room, and high temperatures are to the Y-axis, the better the aberration correction function. Here, low temperature is -20°C or below, for example, in the range of -20 to -50°C, normal temperature is in the range of 22°C ±5°C or in the range of 18°C ​​to 27°C, and high temperature is 85°C or above, for example, in the range of 85°C to 120°C. As a result, it can be seen that the decrease in luminance modulation from low to high temperatures in Figures 15 to 17 is less than 10%, for example, 5% or less, or is almost unchanged. The MTF deviation according to temperature is as shown in Table 7. [Table 7]

[0236] Table 8 compares the changes in optical properties such as EFL, BFL, F-number (F#), TTL, and field of view (FOV) at room temperature, low temperature, and high temperature in the transmitting optical system of the embodiment, and shows that the rate of change in optical properties at low temperatures relative to room temperature is 5% or less, for example, 3% or less or 2% or less, and that the rate of change in optical properties at low temperatures relative to room temperature is 5% or less, for example, 3% or less or 2% or less. [Table 8]

[0237] Therefore, as shown in Table 8, the change in optical characteristics due to temperature changes from low to high, such as the change rate of the effective focal length (EFL), TTL, BFL, F-number (F#), and FOV, is 10% or less, i.e., 5% or less, for example, in the range of 0 to 5%. This means that even if at least one or two aspherical lenses are used, the design allows for temperature compensation for the aspherical lenses, preventing a decrease in the reliability of the optical characteristics. The optical system of the disclosed embodiment can effectively control aberration characteristics such as chromatic aberration and distortion, and can maintain good optical performance both in the central and peripheral areas of the FOV. Furthermore, the transmission optical system can prevent a decrease in optical performance from low to high temperatures by taking into account the characteristics of the vehicle optical system. For example, after designing lenses at room temperature, the value of the refractive index change coefficient (dn / dt) for each temperature can be calculated taking into account the combination of the power of each lens. The temperature coefficient (dn / dt) corresponding to the refractive index of the lens and the defocus for thickness variables at low, room, and high temperatures can be set to 5 μm or less. For this purpose, the first to third lenses 111, 112, and 113 are made of a spherical glass material, and the fourth and fifth lenses 114 and 115 are made of an aspherical glass material.

[0238] The optical system 110 according to the embodiment disclosed above can satisfy at least one or two or more of the mathematical formulas described below. Thereby, the optical system 110 according to the embodiment can have improved optical characteristics. For example, when the optical system 110 satisfies at least one mathematical formula, the optical system 110 can effectively control aberration characteristics such as chromatic aberration and distortion aberration, and can have good optical performance at both the center and peripheral portions of the angle of view FOV. In addition, the receiving optical system 110 can have improved resolution. Further, for the meaning of the thickness of the lens on the optical axis Lz of the lens described in the mathematical formula and the distance between adjacent lenses on the optical axis Lz, reference can be made to the embodiment disclosed above.

[0239] [Formula 1] 0 < CT1 / CT2 < 3 By setting the central thickness CT1 of the first lens 111 and the central thickness CT2 of the second lens 112 in Formula 1, it is possible to prevent a decrease in the rigidity of the first lens 111 and control factors that affect aberration. Preferably, Formula 1 can satisfy 1 < CT1 / CT2 < 3.

[0240] [Formula 2] 5 < CA11 / CT1 < 15 CA11 is the effective diameter of the object side surface S1 of the first lens 111. By setting the central thickness CT1 of the first lens 111 and the effective diameter CA11 of the object side surface S1 of the first lens 111 in Formula 2, when this is satisfied, it is possible to prevent a decrease in the strength and optical characteristics of the lens made of glass material. If it is lower than the range of Formula 1, the lens may be damaged or the emission efficiency may decrease, and if it is larger than the range, the TTL increases and the weight of the optical system becomes heavier. Preferably, Formula 2 can satisfy 7 < CA11 / CT1 < 12.

[0241] [Formula 3] 0 < CT5 / CT4 < 3 The central thickness CT5 of the fifth lens 115 and the central thickness CT4 of the fourth lens 114 can be set by Equation 3, heat compensation can be optimized according to temperature changes from low to high temperatures, and deterioration of optical performance can be prevented. Preferably, Equation 3 can satisfy 1 < CT5 / CT4 < 2.

[0242] [Equation 3-1] 0 < CT5 / CT3 < 3 By setting the central thicknesses CT3 and CT5 of the third and fifth lenses 113 and 115 with Equation 3-1, the light refracted from the lens on the light source side can be guided toward the object. Preferably, Equation 3-1 can satisfy 1 < CT5 / CT3 < 2. Thereby, the fifth lens 115 adjacent to the light source 116 most thickens the central thickness CT5 and can refract light with the lens on the object side without significantly increasing the effective diameter.

[0243] [Equation 4] 0 < CT5 / (CT1 + CT2) < 3 By setting the central thickness CT5 of the fifth lens 115 larger than the sum of the central thicknesses CT1 and CT2 of the first and second lenses 111 and 112 with Equation 4, the light refracted by the lens on the object side can be guided. Preferably, Equation 4 can satisfy 1 < CT5 / (CT1 + CT2) < 2.5. Thereby, the fifth lens 115 adjacent to the light source 116 most thickens the central thickness CT5 and does not significantly increase the effective diameter.

[0244] [Equation 5] 0 < CT5 / CG2 < 1 By setting the center-to-center distance CG2 between the second and third lenses 112 and 113 larger than the central thickness CT5 of the fifth lens 115 with Equation 5, the second lens 112 can be set as a lens having a concave light source side surface and a minimum effective diameter. Also, the effective diameter of the third lens 113 can be increased from the effective diameter of the second lens 112.

[0245] [Equation 6] 0 < CG1 / CG4 < 1.5 By setting the center-to-center distance CG1 between the first and second lenses 111 and 112 and the center-to-center distance CG4 between the fourth and fifth lenses 114 and 115 in Equation 6, the center-to-center distance between spherical lenses and the center-to-center distance between aspherical lenses can be set. Preferably, 0.5 < CG1 / CG4 < 1 can be satisfied.

[0246] [Equation 7] 0 < CG2 / CG4 < 1 By setting the center-to-center distance CG2 between the second and third lenses 112 and 113 larger than the center-to-center distance CG4 between the fourth and fifth lenses 114 and 115 in Equation 7, the center-to-center distance between the aspherical lenses on the light source side can be reduced by the center-to-center distance between the spherical lenses on the object side. Preferably, 0.2 < CG2 / CG4 < 0.8 can be satisfied.

[0247] [Equation 8] 0.5 < CG2 / (CT1 + CG1 + CT2) < 1.5 By setting the center-to-center distance CG2 between the second and third lenses 112 and 113 larger than the optical axis distance between the object side surface of the first lens 111 and the light source side surface of the second lens 112 in Equation 8. Thereby, the effective diameter of the object side surface of the first lens 111 can be set to the maximum, and the second lens 112 can be set to a lens having a concave light source side surface and a minimum effective diameter. Preferably, 1 < CG2 / (CT1 + CG1 + CT2) < 1.5 can be satisfied.

[0248] [Equation 10] 1.70 < n1 n1 is the refractive index of the first lens 111 at the d-line. By setting the refractive index of the first lens 111 high in Equation 10, the factors affecting the reduction of the third-order aberration (Seidel aberration) of the optical system can be adjusted, and the aberration that may occur with a slightly longer TTL can be reduced. Equation 10 can preferably satisfy 1.75 < n1 < 2.1. When designed lower than the lower limit value of Equation 10, the improvement of aberration decreases, the refractive power of the first lens becomes weak, and light cannot be efficiently collected, resulting in a decline in the performance of the optical system. When designed higher than the upper limit value of Equation 10, there is a disadvantage that it becomes difficult to obtain the material. Also, when the refractive index of the first lens 111 is designed lower than the lower limit value of Equation 4, the curvature radii of the first and second lenses are increased to increase the refractive powers of the first and second lenses.

[0249] [Equation 10-1] 1.7 < Aver(n1:n5) < 1.8 Aver(n1:n5) is the average of the refractive index values of the first to fifth lenses at the d-line. When Equation 10-1 is satisfied, the optical system 110 can suppress the influence of TTL.

[0250] [Equation 10-2] GMn_Aver < GLn_Aver GLn_Aver is the average of the refractive index values of the spherical glass lenses at the d-line, and GMn_Aver is the average of the refractive index values of the aspherical glass lenses at the d-line. The spherical lens is a lens made of a glass material that is not injection-molded, and the aspherical lens is a lens made of a glass material of a glass mold. A spherical lens with a high refractive index is located on the object side of the aspherical lens, and the chromatic dispersion can be increased.

[0251] [Equation 11] 0 < n1 / n3 < 1.5 n1 and n3 are the refractive indices of the first and third lenses 111 and 113 at the d-line. By reducing the difference between the refractive index of the first lens 111 and the refractive index of the third lens 113 in Equation 11, it is possible to prevent a decrease in chromatic dispersion due to the glass material lens. Preferably, Equation 11 can satisfy 1 < n1 / n3 < 1.3.

[0252] [Equation 12] 1 < n3 / n4 < 1.5 n3 and n4 are the refractive indices of the third and fourth lenses 113 and 114 at the d-line. By setting the refractive index of the third lens 113 higher than the refractive index of the fourth lens 114 in Equation 12, it is possible to adjust the chromatic dispersion due to the spherical material lens and the chromatic dispersion due to the aspherical lens. Preferably, Equation 12 can satisfy 1 < n3 / n4 < 1.2.

[0253] [Equation 13] (v4 × n4) < (v1 × n1) n1 and n4 are the refractive indices of the first and fourth lenses 111 and 114 at the d-line, and v1 and v4 are the Abbe numbers of the first and fourth lenses. By setting the product of the refractive index and the Abbe number of the first and fourth lenses 111 and 114 higher than the product of the refractive index and the Abbe number of the fourth lens 114 in Equation 13, it is possible to adjust the chromatic dispersion due to the spherical material lens and the chromatic dispersion due to the aspherical lens.

[0254] <{ [Equation 14] SD < TD SD is the optical axis distance from the diaphragm ST to the surface of the light source 116, and TD is the optical axis distance from the object side surface of the first lens 111 to the sensor side surface of the fifth lens 115. When the optical system satisfies Equation 14, the diaphragm ST can be positioned between two different lenses.

[0255] [Equation 14-1] CA11 / 2 < (CT n + CT n-1 ) < CA11 CT n is the central thickness of the nth lens adjacent to the light source 116, and CTn-1 represents the central thickness of the (n - 1)-th lens, and CA11 is the effective diameter of the first lens. By setting the sum of the n-th lens adjacent to the light source 116 and the central thickness of the (n - 1)-th lens in Equation 14-1, the emitted light path can be adjusted. The n-th lens may be the fifth lens, and the (n - 1)-th lens may be the fourth lens.

[0256] [Equation 14-2] 10mm < (CT n + CT n-1 ) < TTL / 3 TTL is the optical axis distance from the center of the object side surface of the first lens 111 to the surface of the light source 116. By setting the optical axis distance between the optical filter 155 and the light source 116 to less than 1 / 3 of the total optical axis length TTL in Equation 14-2, the problem that the emission at normal temperature, low temperature, and high temperature is shifted can be minimized. Preferably, 10mm < (CT n + CT n-1 ) < TTL / 3 can be satisfied.

[0257] [Equation 15] CAn2 / 2 < CTn CAn2 is the effective diameter of the light source side of the n-th lens, and CTn is the central thickness of the n-th lens. When Equation 15 is satisfied, the effective diameter of the n-th lens can be set so as not to be too large compared to the central thickness of the n-th lens.

[0258] [Equation 16] CA52 / 2 < CG2 < CA11 CA52 is the effective diameter of the light source side of the fifth lens, CG2 is the center-to-center distance between the second and third lenses, and CA11 is the effective diameter of the object side surface of the first lens. When Equation 16 is satisfied, the center-to-center distance between the second and third lenses can be increased, and the effective diameter of the fifth lens can be set so as not to increase.

[0259] [Equation 17] CA11 / 2 < CG1 + CG2 The effective diameter of the object side surface of the first lens, the center distance between the first and second lenses, and the center distance between the second and third lenses can be set by Equation 17. When this is satisfied, the number of lenses of the spherical lens can be reduced.

[0260] [Equation 18] 1 < CA11 / CA21 < 5 CA21 means the effective diameter of the third surface S3 of the second lens 112. When Equation 18 is satisfied, the optical system 110 can control the emitted light and set elements that affect aberration. Preferably, 1 < CA11 / CA21 < 2.5 can be satisfied.

[0261] [Equation 19] 0 < CA22 / CA31 < 1.5 CA22 means the effective diameter of the fourth surface S4 of the second lens 112, and CA31 means the effective diameter of the fifth surface S5 of the third lens 113. When Equation 19 is satisfied, the optical system 110 can control the emitted light path and set the light source side surface of the second lens 112 to be concave. Preferably, Equation 19 can satisfy 0.5 < CA22 / CA31 < 1.

[0262] [Equation 20] 0.5 < CA42 / CA51 < 2 CA42 means the effective diameter of the eighth surface S8 of the fourth lens 114, and CA~51 means the effective diameter of the ninth surface S9 of the fifth lens 115. When Equation 20 is satisfied, the optical system 110 can set the light path emitted through the fourth lens 114 and the fifth lens 115. Equation 20 can preferably satisfy 1 < CA42 / CA51 < 1.5.

[0263] [Equation 21] 1 < CA11 / CA51 < 5 When the optical system 110 satisfies Equation 21, the output amount of the spherical lens, which is the first lens, can be increased, and the optical path of the aspherical lens, which is the last lens, can be set. Equation 21 can preferably satisfy 1 < CA11 / CA51 < 2.5.

[0264] [Equation 22] 1 < CG2 / (CT2 + CT3) < 3 When Equation 22 is satisfied, the concave curvature radius of the light source side surface of the second lens 112 can be set, and the optical path between the second and third lenses 112 and 113 can be set. Preferably, 1 < CG2 / (CT2 + CT3) < 2 can be satisfied.

[0265] [Equation 23] 0 < CG4 / (CT4 + CT5) < 1 CG4 is the center-to-center distance between the fourth and fifth lenses, and CT4 and CT5 are the center thicknesses of the fourth and fifth lenses. When Equation 23 is satisfied, the curvature radius of the light source side surface of the fourth lens 114 can be reduced, and the optical path corresponding to the center-to-center distance between the fourth and fifth lenses 114 and 115 can be set. Preferably, 0 < CG4 / (CT4 + CT5) < 0.7 can be satisfied.

[0266] [Equation 24] 1 < CG_Max / CG4 < 4 CG_Max means the maximum of the center-to-center distances between the lenses in the optical system. When Equation 24 is satisfied, the maximum center-to-center distance between the lenses can be positioned closer to the object side than the center-to-center distance between the fourth lens 114 and the fifth lens 115, and an increase in the size of the fourth lens 114 can be suppressed. Preferably, 1.5 < CG_Max / CG4 < 3 can be satisfied.

[0267] [Equation 25] 1 < CT5 / BFL < 4 The BFL is the optical axis distance from the center of the light source side of the last lens to the light source 116. That is, the BFL is the optical axis distance from the center of the light source side of the fifth lens 115 to the light source 116. When the formula 25 is satisfied, the emitted light is transmitted by the fifth lens 115 to the entire area of the fourth lens 104. Preferably, 1 < CT5 / BFL < 2 can be satisfied.

[0268] [Formula 26] 0 < CG3 / CT5 < 1.5 When the formula 26 is satisfied, the effective diameter of the fifth lens 115 can be adjusted. Preferably, 0.1 < CG3 / CT5 < 0.6 can be satisfied.

[0269] [Formula 27] 0 < CG4 / CT5 < 1 When the formula 27 is satisfied, the effective diameter of the fifth lens 115 can be adjusted, and the aberration characteristics of the propagating light can be improved. Preferably, 0.2 < CG4 / CT5 < 0.7 can be satisfied.

[0270] [Formula 28] 0 < |L5R2| / CT5 < 5 L5R2 is the radius of curvature of the light source side surface of the fifth lens. When the formula 28 is satisfied, the refractive power of the fifth lens 115 can be controlled to improve the optical performance.

[0271] [Formula 29] 0 < |L5R2| / L5R1 < 5 L5R1 is the radius of curvature of the object side surface of the fifth lens. When the formula 29 is satisfied, the refractive power of the fifth lens 115 can be controlled to improve the optical performance.

[0272] [Formula 30] 0 < L1R1 / L1R2 < 5 L1R1 is the radius of curvature of the object side surface of the first lens, and L1R2 is the radius of curvature of the light source side surface of the first lens. When the formula 30 is satisfied, the refractive power of the first lens 111 can be controlled to improve the optical performance.

[0273] [Equation 31] 500 < |L2R1| / L2R2 L2R1 is the radius of curvature of the object side surface of the second lens, and L2R2 is the radius of curvature of the light source side surface of the second lens. When Equation 31 is satisfied, the refractive power of the second lens 112 can be controlled to improve the optical performance, and the effective diameter of the light source side lens of the second lens 112 can be adjusted. When the object side surface of the second lens 112 is made flat, lens processing becomes easy.

[0274] [Equation 32] 0 < CT_Max / CG_Max < 2 In Equation 32, the maximum center thickness CT_Max of the lens and the maximum interval CG_Max between adjacent lenses can be set. When Equation 32 is satisfied, the optical system can have good optical performance at the focal length of the set angle of view, and the TTL can be reduced. Preferably, 0 < CT_Max / CG_Max < 1 can be satisfied.

[0275] [Equation 33] 0 < ΣCT / ΣCG < 2 ΣCT is the sum of the center thicknesses of the lenses, and ΣCG is the sum of the intervals between adjacent lenses. When Equation 33 is satisfied, the optical system can have good optical performance at the focal length of the set angle of view, and the TTL can be reduced. Preferably, 1 < ΣCT / ΣCG < 1.5 can be satisfied.

[0276] [Equation 34] 5 < ΣIndex < 15 ΣIndex means the sum of the refractive indices of each d-line of a plurality of lenses. When Equation 34 is satisfied, the TTL can be controlled in the optical system 110 in which an aspherical lens and a spherical material lens are mixed. Also, when the number of spherical material lenses is more than the number of aspherical material lenses, the TTL and the sum of the refractive indices can be set. Equation 34 can preferably satisfy 5 < ΣIndex < 10.

[0277] [Equation 35] 10 < ΣAbbe / ΣIndex < 50 ΣAbbe means the sum of the Abbe numbers of each of the plurality of lenses. When Equation 35 is satisfied, the optical system 110 can have improved aberration characteristics and resolution. By setting Equation 35 with the sum of the Abbe numbers and the sum of the refractive indices of the lenses, the optical characteristics can be controlled, and preferably 10 < ΣAbb / ΣIndex < 30 can be satisfied.

[0278] [Equation 36] 50 < ΣCT × n < 150 [[ID=​​​​​​​​​​​​​​​​​​​​​​​CA_Max indicates the maximum effective diameter between the object side and the light source side of the lens. When Equation 39 is satisfied, the optical system can maintain its optical performance and set the size for a slim and compact structure. Equation 39 can preferably satisfy 1 < CA_Max / CA_Min < 3.

[0282] [Equation 39] 0 < CG2 / CA12 < 2 CG2 is the center-to-center distance between the second and third lenses, and CA12 is the effective diameter of the light source side of the first lens. When Equation 39 is satisfied, the incident light of the spherical lens can be adjusted. Equation 39 can preferably satisfy 0 < CG2 / CA12 < 1.

[0283] [Equation 40] 1 < CA_Max / CA_Aver < 3 CA_Aver indicates the average of the effective diameters of the object side and the light source side of the lens. When Equation 40 is satisfied, the optical system can maintain its optical performance and set a slim and compact sensor device. Equation 40 can preferably satisfy 1 < CA_Max / CA_Aver < 2.

[0284] [Equation 41] 0.1 < CA_Min / CA_Aver < 2 When Equation 41 is satisfied, the optical system can maintain its optical performance and set a slim and compact sensor device. Equation 41 can preferably satisfy 0.5 < CA_Min / CA_Aver < 1.

[0285] [Equation 42] 1 < CA_Max / (2 × LsH) < 6 Equation 42 can set the maximum effective diameter CA_Max and the diagonal length of the light source (2 × LsH). When this is satisfied, the optical system can maintain good optical performance and set a slim and compact sensor device. Equation 42 can preferably satisfy 3 < CA_Max / (2 × LsH) < 4.5.

[0286] [Equation 42-1] 1 < TD / CA_Max < 4 TD is the optical axis distance from the center of the object side surface of the first lens to the center of the light source side surface of the last lens. When Equation 42-1 is satisfied, the overall optical axis distance and the maximum effective diameter of the lens can be set, and the size for good optical performance can be set. Equation 42-1 can preferably satisfy 1 < TD / CA_Max < 3.

[0287] [Equation 43] 0 < F / |L5R2| < 1 F is the effective focal length of the optical system, and L5S2 is the radius of curvature of the light source side surface of the fifth lens. When Equation 43 is satisfied, the effective focal length and the radius of curvature of the light source side surface of the last aspherical lens can be set to adjust the influence on the reduction of the optical system, for example, on TTL. Equation 43 can preferably satisfy 0 < F / |L5R2| < 0.5.

[0288] [Equation 44] 0 < F / L1R1 < 1 By setting the effective focal length of the optical system and the radius of curvature of the object side surface of the first lens in Equation 44, the influence on the outgoing light and TTL can be adjusted. Equation 44 can preferably satisfy 0 < F / L1R1 < 0.5.

[0289] [Equation 45] 0 < EPD / |L5R2| < 1 EPD means the size (mm) of the entrance pupil of the optical system 110, and L5R2 means the radius of curvature of the light source side surface of the fifth lens. When the optical system 110 according to the embodiment satisfies Equation 45, the optical system 110 can control the incident light. Preferably, the condition of 0 < EPD / |L5R2| < 0.5 can be satisfied.

[0290] [Equation 46] 0 < EPD / L1R1 < 1 The size of the entrance pupil of the optical system 110 and the radius of curvature of the object side surface of the first lens can be set by Equation 46. When this is satisfied, the optical system 110 can control the emitted light. Preferably, the condition of 0 < EPD / L1R1 < 0.5 can be satisfied.

[0291] [Equation 47] 0 < |F1 / F2| < 10 F1 is the focal length of the first lens, and F2 is the focal length of the second lens. When Equation 47 is satisfied, the refractive powers of the first and second lenses can be controlled, and the TTL and the effective focal length EFL can be affected. Preferably, the condition of 0 < |F1 / F2| < 2 can be satisfied.

[0292] [Equation 48] 0 < |F1| / F < 10 The focal length of the first lens and the effective focal length of the optical system can be set by Equation 48, and the refractive power of the first lens can be controlled.

[0293] [Equation 49] 0 < |F1 / F5| < 10 The focal lengths of the first and fifth lenses can be set by Equation 49, and the refractive powers of the first and fifth lenses can be controlled. Preferably, the condition of 0 < |F1 / F5| < 5 can be satisfied.

[0294] [Equation 49-1] F5 < |F1| < F3

[0295] [Equation 49-2] F3 < F4

[0296] [Equation 49-3] 2 × |F2| < F4 In Equations 49-1 to 49-3, F1, F2, F3, F4, and F5 are the focal lengths of the first to fifth lenses. By adjusting the focal lengths from the spherical lens to the last aspherical lens, light can be guided to the effective region of the aspherical lens.

[0297] Here, F1 is -10 mm or less, for example, in the range of -10 mm to -30 mm. F2 is -5 mm or less, for example, in the range of -5 mm to -20 mm. F3 is 15 mm or more, for example, in the range of 15 mm to 30 mm. F4 is 16 mm or more, for example, in the range of 16 mm to 40 mm. F5 is 5 mm or more, for example, in the range of 5 mm to 17 mm. The balance of the focal lengths of the lenses can suppress differences in focus position due to temperature changes. This can suppress deterioration of the optical characteristics of the lenses due to temperature changes. The aperture ST is disposed on the object side of the third lens 113. The lens disposed closer to the light source than the aperture ST and closest to the aperture ST has a focal length greater than 0. In this embodiment of the present invention, F3, which is the focal length of the third lens 113, must be designed to be greater than 0. In this case, the third lens 113 collects light, and it is possible to prevent the effective diameters of the fourth and fifth lenses, which are lenses arranged closer to the light source than the third lens 113, from becoming larger, it is possible to prevent the TTL from becoming long, and it is possible to make the transmission optical system compact. In this case, it is possible to provide a wide-angle optical system with an angle of view FOV exceeding 100 degrees, for example, 110 degrees to 130 degrees.

[0298] [Formula 50] Po2×Po3<0 Po2 is the refractive power value of the second lens, and Po3 is the refractive power value of the third lens. That is, the refractive powers of the second and third lenses are opposite to each other, so aberrations can be improved and the aspherical lens can effectively guide light. When Po2 × Po3 > 0, the effect of improving chromatic aberrations in both lenses is minimal.

[0299] [Formula 51] 20mm <TTL<60mm TTL means the distance (mm) on the optical axis Lz from the center of the first surface S1 of the first lens 111 to the upper surface of the light source 116. By setting TTL to be more than 20 mm and less than 60 mm in Formula 51, an optical system for a vehicle can be provided. Formula 51 can preferably satisfy 30 mm < TTL < 55 mm or satisfy the condition of TD < TTL.

[0300] [Formula 52] 2 mm < LsH < 20 mm Formula 52 can set the diagonal size (2 × LsH) of the light source 116 and provide an optical system having the size of a vehicle sensor. Formula 52 can preferably satisfy 2 mm < LsH < 5 mm.

[0301] [Formula 53] 1.5 mm < BFL < 7 mm By setting BFL to be more than 1.5 mm and less than 7 mm in Formula 53, an installation space for the cover glass 153 can be secured, the assembly property of components can be improved by the interval between the light source 116 and the last lens, and the coupling reliability can be improved. Formula 53 can preferably satisfy 5 mm < BFL < 7 mm. When the BFL is less than the range of Formula 53, some light emitted from the light source will not be emitted, causing a decrease in resolution. When the BFL exceeds the range of Formula 53, stray light is emitted, causing a decrease in the aberration characteristics of the optical system.

[0302] [Formula 54] 1 mm < F < 10 mm Formula 54 can set the overall focal length F to suit the optical system for a vehicle. Formula 54 can satisfy 1 mm < F < 5 mm.

[0303] [Formula 55] 100 degrees < FOV In Equation 55, FOV (Field of view) means the angular field (Degree) of the optical system 110, and a vehicle optical system having an angular field FOV exceeding 100 degrees can be provided. The FOV preferably satisfies 110 degrees ≤ (= also includes, less than or equal to) FOV ≤ (= also includes, less than or equal to) 130 degrees. The range of the vehicle optical system can be set by the angular field in Equation 55. The light source length in the horizontal direction is based on 6.80 mm ± 0.5 mm. Also, when Equation 55 is satisfied, when the temperature changes from normal temperature to high temperature, the change rate of the effective focal length and the change rate of the angular field can be set to 5% or less, for example, 0 to 5%. Further, even if two or more aspherical lenses are mixed with spherical lenses in the optical system 110, the deterioration of optical characteristics can be prevented by temperature compensation and aberration correction by the aspherical lenses made of glass material.

[0304] [Equation 56] 1 < TTL / CA_Max < 7 In Equation 56, CA_Max means the largest effective diameter (mm) of the object side and the light source side of the plurality of lenses, and TTL means the distance (mm) on the optical axis Lz from the vertex of the first surface S1 of the first lens to the upper surface of the light source 116. Equation 56 can set the relationship between the overall optical axis length and the maximum effective diameter of the optical system, and can provide an improved vehicle optical system. Equation 56 preferably satisfies 1 < TTL / CA_Max < 3.

[0305] [Equation 57] 10 < TTL / LsH < 30 Equation 57 can set the overall optical axis length TTL of the optical system and the diagonal length LsH in the optical axis direction of the light source 116. When the optical system 110 according to the embodiment satisfies Equation 57, the optical system 110 can have a TTL for the application of the vehicle light source 116 and can provide a more improved image quality. Equation 57 preferably satisfies 10 < TTL / LsH < 20.

[0306] [Equation 58] 0 < BFL / LsH < 3 Equation 58 can set the optical axis interval between the light source 116 and the last lens and the length in the diagonal direction with respect to the optical axis of the light source 116. When the optical system 110 according to the embodiment satisfies Equation 58, the optical system 110 can secure a BFL for applying the size of the vehicle light source 116, can set the interval between the last lens and the light source 116, and can have good optical characteristics within the angle of view FOV. Equation 58 can preferably satisfy 1 < BFL / LsH < 2.

[0307] [Equation 59] 1 < TTL / BFL < 15 Equation 59 can set the overall optical axis length TTL of the optical system and the optical axis interval BFL between the light source 116 and the last lens. When the optical system 110 according to the embodiment satisfies Equation 59, the optical system 110 can secure a BFL. Equation 59 can preferably satisfy 3 < TTL / BFL < 13.

[0308] [Equation 60] 10 < TTL / F < 30 Equation 60 can set the overall focal length F and the overall optical axis length TTL of the optical system 110. Thereby, an optical system for a driver assistance system can be provided. Equation 60 can preferably satisfy 10 <= (including =, less than or equal to) TTL / F < 25 or 12 < TTL / F < 20. When the optical system 110 according to the embodiment satisfies Equation 60, the optical system 110 can have an appropriate focal length within the set TTL range, can maintain an appropriate focal length even when the temperature changes from low to high, and can provide an optical system capable of imaging. If it is less than the lower limit value of Equation 60, it is necessary to increase the refractive power of the lens, and it becomes difficult to correct spherical aberration or distortion aberration. If it exceeds the upper limit value of Equation 60, problems such as an increase in the effective diameter and TTL of the lens and enlargement of the imaging lens system may occur.

[0309] [Equation 61] 0 < F / BFL < 3 Equation 61 can set the overall focal length F of the optical system 110 and the optical axis interval BFL between the light source 116 and the last lens. When the optical system 110 according to the embodiment satisfies Equation 61, the optical system 110 can have a set angle of view, can have an appropriate focal length, and can provide an optical system for a vehicle. Also, the optical system 110 can minimize the interval between the last lens and the light source 116 and can have good optical characteristics at the angle of view FOV. Equation 61 can preferably satisfy 0 < F / BFL < 1.

[0310] [Equation 62] 0.5 < F / LsH < 1.5 Equation 62 can set the overall focal length F (mm) of the optical system 110 and the diagonal length LsH on the optical axis of the light source 116. Such an optical system 110 can have improved aberration characteristics in terms of the size of the vehicle light source 116. Equation 62 can preferably satisfy 0.7 < F / LsH < 1.

[0311] [Equation 63] 0.5 < F / EPD < 1.5 Equation 63 can set the overall focal length F of the optical system 110 and the size of the entrance pupil. Thereby, the overall brightness of the optical system can be controlled. Equation 63 can preferably satisfy 0.5 < F / EPD < 1.

[0312] [Equation 64] 0 < EPD / LsH / FOV < 0,2 Equation 64 can set the relationship between the size EPD of the entrance pupil, the length LsH which is half of the maximum diagonal length of the image sensor, and the angle of view. Thereby, the overall size and brightness of the optical system can be controlled. Equation 64 can preferably satisfy 0 < EPD / LsH / FOV < 0.1.

[0313] [Equation 65] 100 < FOV / F# < 200 Equation 65 can set the relationship between the angle of view of the optical system and the F-number F#. Equation 65 can preferably satisfy 120 < FOV / F# < 170. Here, F# can be provided to be 1.2 or less to provide a bright image.

[0314] [Equation 66] 50 < (CT_Max + CG_Max) × n < 150

[0315] [Equation 67] 800 < (FOV × TTL) / n Preferably, Equation 67 can satisfy the condition of 1000 < (FOV × TTL) / n < 1500 according to the angle of view and the number of lens elements n.

[0316] [Equation 68] FOV < (TTL × n)

[0317] ​​​​​​​​​​​​​​The optical system 110 according to the embodiment may satisfy at least one or more of Equations 1 to 70. In this case, the optical system 110 may have improved optical characteristics. Specifically, when the optical system 110 satisfies at least one of Equations 1 to 35 and / or at least one of Equations 36 to 70, the optical system 110 may have improved resolving power and improved aberration and distortion characteristics. In addition, the transmitting optical system 110 may secure a BFL for applying the vehicular light source 116, compensate for deterioration of optical characteristics due to temperature changes, minimize the distance between the last lens and the light source 116, and have good optical performance within the field of view (FOV). The BFL may be defined as a first BFL for the receiving optical system and a second BFL for the transmitting optical system.

[0320] Table 9 relates to the items in the above-mentioned formula for the transmitting optical system 110 of the embodiment, such as the TTL (mm), BFL, effective focal length F, LsH, effective diameter CA, sum of the central thicknesses of each lens, sum of the central spacings between adjacent lenses, TTL (mm), sum of Abbe numbers, sum of refractive indexes, TD (mm) which is the optical axial distance from the first surface S1 to the tenth surface S10, focal lengths F1, F2, F3, F4, F5 of the first to fifth lenses, angle of view FOV, edge thickness ET, F-number, etc. [Table 9]

[0321] Table 10 shows the results of the above-described formulas 1 to 35 in the transmission optical system 110 of the embodiment. Referring to Table 10, it can be seen that the transmission optical system 110 satisfies at least one, two or more, or three or more of formulas 1 to 35. This allows the transmission optical system 110 to have good optical performance within the field of view FOV, and excellent optical characteristics. [Table 10] TIFF2025534649000015.tif80141

[0322] Table 11 shows the results of the above-described formulas 36 to 70 in the optical system 110 of the example. Referring to Table 11, it can be seen that the optical system 110 satisfies at least one, two or more, or three or more of formulas 36 to 70. This allows the optical system 110 to have good optical performance within the field of view FOV, and excellent optical characteristics. [Table 11] TIFF2025534649000017.tif205134

[0323] 18 is a block diagram of a sensor system having a transmission optical system according to an embodiment of the present invention. Referring to FIG. 18, the sensor device includes a control unit 10, a light source driving unit 20, a transmission optical system 30, the above-disclosed reception optical system 50, and a signal processing unit 60. The control unit 10 controls the transmission and reception of signals, and can communicate with 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 and received signals.

[0324] The light source driver 20 supplies power to the light source included in the transmission optical system 30 to drive it. The light source generates laser light in the form of a line light source or a point light source. The light source driver 20 can adjust or vary the driving current supplied to the light source according to driving environment information. The driving environment information can include topographical information of the driving section, traffic congestion information, weather, etc. The wavelength of the laser light generated from the light source can be in the range of 890 nm to 960 nm or 940 nm ± 10 nm. The laser light source can be implemented as an InGaAs / GaAs-based semiconductor diode laser and can emit high-power laser light. The light source can include a single emitter and / or multiple emitters.

[0325] The transmitting optical system 30 transmits laser light generated from a light source to the object 40, and the light reflected by the object 40 is received by the receiving optical system 50. The receiving optical system 50 may be composed of a number of optical sensors, each of which converts the received light into an electrical signal using a photodiode. That is, image sensors are arranged in a matrix type and convert the light received from the object scanned in the horizontal and vertical directions into an electrical current. The signal processing unit 60 converts the output of the receiving optical system 50 into a voltage, amplifies it, and then converts the amplified signal into a digital signal using an analog-to-digital converter. The signal processing unit 60 analyzes the digital data using a time-of-flight (TOF) algorithm or a phase-shift algorithm to detect the distance to the object 40 and the shape of the object.

[0326] The control unit 10 may receive vehicle speed information and road surface condition information via a control unit (ECU) or a network. The control unit 10 may receive driving environment information via a network. The driving environment information may include topographical information of a driving section, traffic congestion information, weather, etc. The control unit 10 may adjust a gain based on one or more of the vehicle speed, the road surface condition of the road on which the vehicle is driving, and the driving environment information, and may provide sensor data including the distance to an object and shape information of the object to the autonomous driving device.

[0327] FIG. 19 is a diagram showing an example of measuring an object using a vehicle having a sensor system of the invention, and FIG. 20 is a diagram showing an example of monitoring surroundings using a vehicle having a sensor system of the invention.

[0328] 19 and 20, a vehicle 202 having a sensor system includes transmit optics that project laser light 201 generated by a light source toward a target scene, and receive optics that receive light 203 reflected from the target or object 210. The sensor system also includes a LiDAR system, which typically also includes a controller that calculates distance information to the object 106 from the reflected light, and an element that can scan or provide a specific pattern of light, which may be a static pattern within a desired range and field of view (FOV). The transmit and receive optics are used to convert the received signal light into measurements that represent a point-by-point 3D map of the surrounding environment within the range and FOV of the LiDAR system.

[0329] The LIDAR receiver optics and signal processor calculate range information based on time-of-flight measurements of light pulses emitted from the light source. Additionally, the scene is illuminated onto a target surface associated with a particular range, and known information about the light beam profile based on the specific design of the source and projector system is used to determine positional information about reflecting surfaces, 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 a collection of measurement data that indicates positional information from all surfaces within the LIDAR system's field of view that reflect illumination from the source to the receiver. In this manner, a 3D representation of the objects in the LIDAR system's field of view is obtained.

[0330] Also shown is a schematic diagram illustrating the two-dimensional field of view and range requirements of a typical surrounding-sensing LIDAR system 200 for an automobile 202. For example, an adaptive cruise control function may require a field of view and range 204 with a narrower field of view but a longer distance range requirement compared to a side-viewing "surround view" field of view and range 206. Typically, a vehicle's sensor functions are enabled by a combination of LIDAR, radar, cameras, and ultrasonic sensors. The combination of these sensor data to generate information about the surrounding environment is sometimes referred to as "sensor fusion." While the present invention describes a LIDAR system in the context of an automobile, where LIDAR is widely used for autonomous, self-driving, or driver-assisted vehicles, it should be understood that embodiments may be applied to any vehicle. Other types of vehicles may include robots, tractors, trucks, airplanes, unmanned aerial vehicles, boats, ships, etc.

[0331] The features, structures, effects, etc. described in the above embodiments are included in at least one embodiment of the present invention and are not necessarily limited to one embodiment. Furthermore, the features, structures, effects, etc. exemplified in each embodiment can be combined or modified with other embodiments by a person skilled in the art to which the embodiment belongs. Therefore, the contents related to such combinations and modifications should be interpreted as being included in the scope of the present invention.

[0332] Furthermore, although the above description has focused on the embodiments, these are merely examples and are not intended to limit the present invention. A person skilled in the art to which the present invention pertains may make various modifications and applications not exemplified above within the scope of the essential characteristics of the present embodiments. For example, each component specifically presented in the embodiments may be modified and implemented. Differences related to such modifications and applications should be construed as being included within the scope of the present invention as defined by the appended claims.

Claims

1. a first lens adjacent to the object, the n-th lens (n is 6 or less) adjacent to the image sensor, a plurality of lenses arranged between the first lens and the n-th lens and aligned with the optical axis, an optical filter disposed in any one of the regions between the plurality of lenses, comprising: the optical axis distance from the optical filter to the surface of the image sensor is D1, the optical axis distance from the sensor side surface of the n-th lens adjacent to the image sensor to the surface of the image sensor is BFL, a receiving optical system satisfying the formula: BFL < D1.

2. a diaphragm disposed between the lens disposed on the object side of the optical filter and the optical filter and disposed around the lens disposed on the object side of the optical filter, SD is the optical axis distance from the diaphragm to the surface of the image sensor, the receiving optical system according to claim 1, satisfying the formula: 1 < SD / D1 < 1.

2.

3. CT n is the center thickness of the nth lens, CT n-１ is the center thickness of the (n-1)th lens located on the object side of the nth lens, TTL is the optical axis distance from the center of the object side surface of the first lens to the surface of the image sensor, Mathematical formula: (CT n + CT n-１ ) < D1 < TTL / 2, the receiving optical system according to claim 1 that satisfies this condition.

4. the receiving optical system according to claim 1, wherein the optical filter is a band-pass filter that passes through a range of 890 nm to 960 nm.

5. the optical system according to any one of claims 1 to 4, wherein the first lens includes a convex object side surface and a concave sensor side surface on the optical axis.

6. the receiving optical system according to claim 5, wherein the second lens spaced from the first lens toward the sensor side has a flat object side surface and a concave sensor side surface.

7. the third lens spaced from the optical filter toward the object side has convex surfaces on both sides on the optical axis, the receiving optical system according to claim 5, wherein the fourth lens spaced from the optical filter toward the sensor side has convex surfaces on both sides on the optical axis.

8. the receiving optical system according to claim 5, wherein the n-th lens has a convex object side surface and a convex sensor side surface on the optical axis.

9. the first lens has a negative refractive power, the n-th lens has a positive refractive power, the receiving optical system according to any one of claims 1 to 4, wherein the number of lenses having a positive refractive power among the plurality of lenses is greater than the number of lenses having a negative refractive power among the plurality of lenses.

10. the object side surface of the first lens has the largest effective diameter among the lenses of the optical system, a sensor side surface of the second lens disposed on the sensor side of the first lens has the smallest effective diameter among the lenses of the optical system; the first lens is a spherical lens, The receiving optical system according to claim 4 , wherein the n-th lens is a fifth lens and is an aspherical lens.

11. a first lens closest to the object; the nth lens (n ​​is 6 or less) closest to the light source; a plurality of lenses disposed between the first lens and the nth lens and aligned with an optical axis; the first lens has a meniscus shape that bulges toward the object side, the n-th lens has a biconvex shape on the optical axis; the (n-1)-th lens on the object side from the n-th lens has a convex surface on both sides on the optical axis, the first lens is made of glass, and the object side and the light source side on the optical axis are spherical; The n-th lens is made of glass, and the object side and the light source side on the optical axis are aspherical.

12. The transmission optical system according to claim 11 , wherein the second lens disposed on the light source side of the first lens has a flat object side and a concave light source side on the optical axis.

13. a third lens disposed on the light source side of the second lens, the third lens having convex surfaces on both sides thereof on the optical axis; a fourth lens disposed on the light source side of the third lens, the fourth lens having convex surfaces on both sides thereof on the optical axis; the third lens has spherical surfaces on both sides of the optical axis, The transmission optical system according to claim 12 , wherein the fourth lens has aspherical shapes on both sides thereof on the optical axis.

14. the first lens has a negative refractive power; the n-th lens is a fifth lens and has a positive refractive power; 14. The transmission optical system according to claim 11, wherein the number of lenses having positive refractive power is greater than the number of lenses having negative refractive power.

15. a receiving optical system having an image sensor and first to fifth lenses aligned on a first optical axis from the object toward the image sensor; a transmission optical system having a light source and sixth to tenth lenses aligned on a second optical axis from the object toward the light source, the first to fifth lenses include a spherical lens and an aspherical lens, the sixth to tenth lenses include a spherical lens and an aspherical lens, the receiving optical system includes an optical filter disposed between a spherical lens and an aspherical lens; each of the first lens and the sixth lens has a meniscus shape that bulges toward an object side; the fifth lens has an object side surface and a sensor side surface each having a convex and aspherical shape on the first optical axis; the tenth lens has an object-side surface and a light-source-side surface that are convex and aspherical on the second optical axis, the light source generates light in the range of 890 nm to 960 nm; The optical filter transmits light in the range of 890 nm to 960 nm.

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