Optical system and camera module

Abstract

The optical system disclosed in the embodiments of the invention may include a first lens to a fifth lens arranged in order from the object side, wherein the composite power of the first lens and the second lens is negative, the composite power of the third lens to the fifth lens is positive, the effective diameter of the second lens among the first to fifth lenses is the smallest, the effective diameter of the first lens is larger than the effective diameter of the second lens and smaller than the effective diameters of the third to fifth lenses, the power of the third lens is the largest among the first to fifth lenses, and the power of the fourth lens is the second largest among the first to fifth lenses.

Description

[Technical Field]

[0001] The embodiments relate to an optical system and a camera module including the same. [Background technology]

[0002] ADAS (Advanced Driving Assistance System) is an advanced driving assistance system that assists the driver by sensing the situation ahead, judging the situation based on the sensing results, and controlling the vehicle's movement based on the situation judgment.With the rapid global growth of ADAS, driver monitoring systems (DMS) are quickly being converted into an important safety function.

[0003] The DMS camera linked to the advanced driver assistance system can be installed inside or outside the vehicle to detect the vehicle's surroundings. The camera can also be installed inside the vehicle to detect the driver and passengers' conditions. For example, the camera can be positioned adjacent to the driver to capture the driver's image and detect the driver's health, whether they are drowsy, whether they have been drinking, etc. The camera can also be positioned adjacent to the passenger to capture the passenger's image and detect whether they are sleeping, their health, etc., and provide the driver with information about the passenger.

[0004] The most important element for obtaining an image with a camera is the imaging lens that forms the image. Recently, interest in high performance, such as high image quality and high resolution, has been growing, and research into optical systems including multiple lenses is being conducted to achieve this. However, when the camera is exposed to harsh environments inside a vehicle, such as high temperature, low temperature, moisture, and high humidity, the characteristics of the optical system can change. In this case, it is difficult for the camera to consistently achieve excellent optical and aberration characteristics. Therefore, a new optical system and camera that can solve the above problems is needed. Summary of the Invention [Problem to be solved by the invention]

[0005] The embodiments provide an optical system and a camera module with improved optical characteristics. The embodiments provide an optical system and a camera module with excellent optical performance in low-temperature and high-temperature environments. The embodiments provide an optical system and a camera module that can prevent or minimize changes in optical characteristics over various temperature ranges. The embodiments can be used in cameras for vehicle interiors or DMS. [Means for solving the problem]

[0006] An optical system according to an embodiment of the invention may include a first lens to a fifth lens arranged in order from the object side, wherein the first lens and the second lens have a negative composite power, the third lens to the fifth lens have a positive composite power, the second lens has the smallest effective diameter among the first to fifth lenses, the first lens has an effective diameter larger than that of the second lens and smaller than that of the third to fifth lenses, the third lens has the largest power among the first to fifth lenses, and the fourth lens has the second largest power among the first to fifth lenses.

[0007] An optical system according to an embodiment of the invention includes a first lens to a fifth lens arranged in order from the object side, wherein the first lens and the second lens have a negative composite power, the third lens to the fifth lens have a positive composite power, the second lens has the smallest effective diameter among the first to fifth lenses, the third lens has the largest power among the first to fifth lenses, and the optical axial distance from the object side surface of the first lens to the sensor side surface of the second lens can be in the range of 26% to 36% of the optical axial distance from the object side surface of the third lens to the sensor side surface of the fifth lens.

[0008] An optical system according to an embodiment of the invention includes a first lens to a fifth lens arranged in order from the object side, and a diaphragm arranged around between the first lens and the second lens, and the second lens may have the smallest effective diameter among the first to fifth lenses, the third lens may have a positive power, the fourth lens may have the largest power among the first to fifth lenses, and the fourth lens may have a positive power that is greater than the powers of the first, second, and fifth lenses.

[0009] According to an embodiment of the invention, the fourth lens may include an image sensor, and the object side surface and the sensor side surface of the fourth lens may have the same radius of curvature, and the fourth lens may have the largest central thickness among the first to fifth lenses.

[0010] According to an embodiment of the invention, the center distance between the third lens and the fourth lens may be larger than the center distance between the first lens and the second lens and the center distance between the second lens and the third lens. According to an embodiment of the invention, the center distance between the fourth lens and the fifth lens may be the largest of the center distances between the first to fifth lenses. According to an embodiment of the invention, the first to fifth lenses may be arranged to be spaced apart from each other along the optical axis. According to an embodiment of the invention, the power of each of the two lenses having positive power and arranged consecutively on the sensor side of the aperture may be more than twice the absolute value of the power of the other lenses.

[0011] According to an embodiment of the invention, the optical axis distance from the object side surface of the third lens to the image sensor disposed on the sensor side of the fifth lens may be in the range of 75% to 85% of the optical axial distance from the object side surface of the first lens to the image sensor. According to an embodiment of the invention, the first lens may have a meniscus shape that bulges from the optical axis toward the object side, and the second lens may have a meniscus shape that bulges from the optical axis toward the sensor side.

[0012] According to an embodiment of the invention, the third lens may have a biconvex shape on the optical axis, and the fourth lens may have a biconvex shape on the optical axis. The fifth lens may have a meniscus shape that bulges from the optical axis toward the sensor. The first lens may have aspheric surfaces on the object side and the sensor side.

[0013] According to an embodiment of the invention, the second to fifth lenses may have spherical object-side and sensor-side surfaces. The effective diameters of the third to fifth lenses may be smaller than the diagonal length of the image sensor. The refractive indexes of the third and fourth lenses may be higher than the average of the refractive indexes of the first to fifth lenses. The first to fifth lenses are made of glass, and the object-side and sensor-side surfaces are provided without critical points.

[0014] According to an embodiment of the invention, S7SagD1 is the Sag data at a point separated from the center on the object side of the fourth lens by a first distance, S8SagD1 is the Sag data at a point separated from the center on the sensor side of the fourth lens by the first distance, and the mathematical formula: |S7SagD1| - |S8SagD1| < 0.2 mm can be satisfied. The first distance is a point that is 1 / 2 of the average effective radius of the object side surface and the sensor side surface of the fourth lens, and the mathematical formulas: S7SagD1 > 0 and S8SagD1 < 0 can be satisfied. The maximum distance in the optical axis direction from the straight line orthogonal to the optical axis to the object side surface of the fifth lens to the object side surface of the fifth lens is Max_Sag51, and the maximum distance in the optical axis direction from the straight line orthogonal to the optical axis to the sensor side surface of the fifth lens to the sensor side surface of the fifth lens is Max_Sag52, and the mathematical formula: |Max_Sag52| < |Max_Sag51| can be satisfied. The mathematical formulas: Max_Sag51 < 0 and Max_Sag51 < 0 can be satisfied.

[0015] The camera module according to an embodiment of the invention includes the optical system disclosed above. The optical axis distance from the object side surface of the first lens to the image sensor is TTL, the total number of lenses is nL, the number of aspherical lenses among the first to fifth lenses is nASL, and 1 / 2 of the diagonal length of the image sensor is ImgH, and the mathematical formulas: 3 < TTL / ImgH < 5, 0 < nASL / nL < 0.5 can be satisfied.

Effect of the Invention

[0016] The optical system and the camera module according to the embodiment can have improved optical characteristics. Specifically, in the optical system according to the embodiment, the plurality of lenses can have set thicknesses, powers, and intervals between adjacent lenses. Thereby, the optical system and the camera module according to the embodiment can have improved MTF characteristics, aberration control characteristics, resolution characteristics, etc. within a set angle-of-view range, and can have good optical performance at the peripheral part of the angle-of-view.

[0017] <000006The optical system and camera module according to the embodiments can have good optical performance in a temperature range from low (approximately -20°C to -40°C) to high (85°C to 105°C). More specifically, the lenses included in the optical system can have a predetermined material, power, and refractive index. As a result, even if the focal length of each lens changes due to a change in refractive index caused by a temperature change, the lenses can compensate for each other. That is, the optical system can effectively distribute power in a temperature range from low to high, thereby preventing or minimizing changes in optical characteristics in a temperature range from low to high. Therefore, the optical system and camera module according to the embodiments can maintain improved optical characteristics in a variety of temperature ranges.

[0018] The optical system and camera module according to the embodiments can achieve a set angle of view by combining aspherical and spherical lenses and can realize excellent optical characteristics. As a result, the optical system can provide a slimmer vehicle camera module. Therefore, the optical system and camera module 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 exterior of a vehicle or inside a vehicle in the summer heat. The embodiments can improve the reliability of cameras for vehicle interiors or DMS. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a side cross-sectional view of an optical system according to an embodiment and a camera module having the optical system.

[0020] [Figure 2] FIG. 2 is a side cross-sectional view for explaining the relationship between the n-th and (n-1)-th lenses in FIG.

[0021] [Figure 3] FIG. 3 is a table showing the lens characteristics of the optical system of FIG.

[0022] [Figure 4]FIG. 4 is a table showing the aspherical coefficients of the lenses in the optical system of FIG.

[0023] [Figure 5] FIG. 5 is a table showing the center thickness of each lens and the center spacing between adjacent lenses in the optical system of FIG.

[0024] [Figure 6] FIG. 6 is a table showing the sag data of the nth and (n-1)th lenses in the optical system of FIG. 1 on the object side and sensor side, from the optical axis to the end of the effective area.

[0025] [Figure 7] FIG. 7 is a graph showing data on the diffraction MTF (Modulation Transfer Function) of the optical system of FIG. 1 at room temperature.

[0026] [Figure 8] FIG. 8 is a graph showing data for the diffraction MTF at low temperatures for the optical system of FIG.

[0027] [Figure 9] FIG. 9 is a graph showing data for the diffraction MTF at high temperatures for the optical system of FIG.

[0028] [Figure 10] FIG. 10 is a graph showing data on the aberration characteristics of the optical system of FIG. 1 at room temperature.

[0029] [Figure 11] FIG. 11 is a graph showing data on the aberration characteristics of the optical system of FIG. 1 at low temperatures.

[0030] [Figure 12] FIG. 12 is a graph showing data on the aberration characteristics of the optical system of FIG. 1 at high temperatures.

[0031] [Figure 13]FIG. 13 is an example of a vehicle having an optical system according to an embodiment of the invention. DETAILED DESCRIPTION OF THE INVENTION

[0032] 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.

[0033] 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.

[0034] In the description of the invention, the term "object-side surface" can refer to the surface of a lens facing the object side relative to the optical axis OA, and the term "sensor-side surface" can refer to the surface of a lens facing the imaging plane (image sensor) relative to the optical axis. A convex lens surface can refer to a convex shape on the optical axis or in the paraxial region, and a concave lens surface can refer to a concave shape in the optical axis or in the paraxial region. The radius of curvature, center thickness, focal length, and optical axis spacing between lenses listed in the lens data tables can refer to values ​​(unit: mm) on the optical axis. The vertical direction can refer to the direction perpendicular to the optical axis, and the end of a lens or lens surface can refer to the end of the effective area of ​​the lens through which incident light passes. The effective diameter or radius of curvature of a lens surface can 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 OA to light rays 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.

[0035] As shown in FIGS. 1 and 2 , an optical system 1000 according to an embodiment of the invention may include multiple lens groups LG1 and LG2. Specifically, each of the multiple lens groups LG1 and LG2 includes at least one lens. For example, the optical system 1000 may include a first lens group LG1 and a second lens group LG2 sequentially arranged along an optical axis OA from the object side toward the image sensor 300. The first lens group LG1 and the second lens group LG2 may have different numbers of lenses. The number of lenses in the second lens group LG2 may be greater than the number of lenses in the first lens group LG1, for example, more than twice or three times the number of lenses in the first lens group LG1. The optical system 1000 may include n lenses, where the nth lens may be the lens closest to the image sensor 300, and the (n-1)th lens may be the lens closest to the nth lens. The n may be an integer equal to or less than 6, for example, 4 to 6. The first lens group LG1 may include at least one lens. The first lens group LG1 can have two or fewer lenses, for example, one lens. The second lens group LG2 can include three or more lenses, or four or more lenses. The second lens group LG2 can also include four lenses.

[0036] The first lens group LG1 may include at least one glass lens. The lens closest to the object side of the first lens group LG1 may be made of a glass lens. Such glass materials have little expansion and contraction due to changes in external temperature and have scratch-resistant surfaces, preventing surface damage. The lenses of the second lens group LG2 may include at least one glass lens and at least one plastic lens. Preferably, the lenses of the second lens group LG2 may include glass lenses. The first lens group LG1 may include at least one aspherical lens. The second lens group LG2 may include at least one spherical lens and at least one aspherical lens. The lenses of the second lens group LG2 may include spherical lenses. Here, a spherical lens is a lens whose object-side and sensor-side surfaces are spherical with respect to the optical axis, and an aspherical lens is a lens whose object-side and / or sensor-side surfaces are aspherical. Here, since the first lens is an aspherical lens closest to the object, the thickness of the first lens can be thinner than a spherical lens, and the short TTL can reduce chromatic dispersion and peripheral image distortion. The first lens may be a glass molded lens. The glass molded lens is a lens made by injection molding a glass material to have an aspherical surface. The TTL (Total Track Length) is the optical axis distance from the center of the object side of the first lens to the surface of the image sensor 300.

[0037] The optical system 1000 is configured with glass lenses, which allows for thermal compensation within the lens barrel and prevents deterioration of optical characteristics due to temperature changes. In addition, the optical system 1000 includes at least one aspherical lens, which prevents various aberrations from occurring.

[0038] The lenses in the optical system 1000 may have a maximum Abbe number of 55 or greater, and the lens with the highest refractive index may be located in the second lens group LG2 and be 1.70 or greater. The lens with the maximum Abbe number may reduce chromatic dispersion, while the lens with the highest refractive index may increase chromatic dispersion of incident light. The refractive index of the i-th lens is Ndi, and the Abbe number of the i-th lens is Adi. The value of Ndi x Adi may be maximum when i is at least one or all of 1, 2, and 5. In addition, when the value of Ndi x Adi is 55 or greater, i = 1, 2, 3, 4, and 5, and the value of Ndi x Adi is not less than 50. The lens with the smallest effective diameter in the optical system 1000 may satisfy the condition that the value of ndi x Adi is 80<(Ndi x Adi)<120, where x represents multiplication.

[0039] The lens with the largest effective diameter in the lens unit 100 may be a spherical lens, and the lens with the smallest effective diameter may be a spherical lens. The effective diameter of each lens may be the diameter of an effective area where effective light is incident on each lens, and is the average of the effective diameter of the object-side surface and the effective diameter of the sensor-side surface. The lens with the largest absolute Sag value in the lens unit 100 is the lens with the smallest effective diameter, and the lens with the second largest Sag value is the nth lens. The Sag value is the distance in the optical axis direction between the object-side surface or the sensor-side surface of each lens, a line perpendicular to the center of the object-side surface or the center of the sensor-side surface. In an embodiment of the invention, an aspherical lens may be disposed on the object side of the optical system 1000 to increase the Sag values ​​of the lens with the smallest effective diameter and the nth lens, thereby diffusing traveling light. Since the object-side surface and the sensor-side surface of the nth lens are provided without a critical point, the overall length (TTL) can be reduced.

[0040] Each of the lenses may include an effective region and a non-effective region. The effective region may be a region through which light incident on each of the lenses passes. That is, the effective region may be an effective region where the incident light is refracted to embody optical characteristics or can be defined as effective. The non-effective region is disposed around the effective region and can be defined by a flange portion. The non-effective region may be a region where effective light is not incident on the plurality of lenses. That is, the non-effective region may be a region irrelevant to the optical characteristics. Also, an end portion of the non-effective region may be a region fixed to a lens barrel (not shown) that houses the lens.

[0041] In the optical system 1000, the TTL (Total top length) may be more than 3 times and, for example, more than 3 times and less than 5 times that of ImgH. Preferably, the condition of 3 < TTL / ImgH < 5 can be satisfied. The ImgH is 1 / 2 of the diagonal length of the image sensor 300 on the optical axis OA. By providing an effective focal length EFL of 10 mm or less and an angular field of view FOV in the diagonal direction of more than 45 degrees within the optical system 1000, it can be provided as a standard optical system for a vehicle camera module. That is, the focal length can be reduced to 10 mm or less for the angular field of view in the diagonal direction. For example, the optical system and camera module according to the embodiment can be applied to a camera module for DMS provided inside a vehicle cabin. The value of TTL / (2×ImgH) in the optical system 1000 may be more than 1.5, for example, the condition of 1.5 < TTL / (2×ImgH) < 2.5 can be satisfied. By setting the value of TTL / (2×ImgH) of the optical system 1000 to less than 2.5, an optical system for driver monitoring can be provided. The total number of lenses in the first and second lens groups LG1 and LG2 is 6 or less. Thereby, the optical system 1000 can provide an image without exaggeration or distortion to the imaged image.

[0042] The length of the image sensor 300 is the maximum length of a diagonal line perpendicular to the optical axis OA. The number of lenses in the optical system 1000 having an effective diameter larger than the diagonal length of the image sensor 300 may be one or less, and the number of lenses having an effective diameter smaller than the length of the image sensor 300 may be four or more. Preferably, the lens having an effective diameter larger than the diagonal length of the image sensor 300 is the nth lens or the (n-1)th lens, or may be absent. The diagonal length of the image sensor 300 may be larger than the diameter of the spherical lens. The diagonal length of the image sensor 300 may be larger than the diameter of the aspherical lens. Preferably, half of the diagonal length of the image sensor 300 may be larger than the minimum effective diameter of the lens.

[0043] The aperture stop ST can adjust the amount of light incident on the optical system 1000. The aperture stop ST is disposed between any two lenses in the lens unit 100. The lenses adjacent to the object side and sensor side of the aperture stop ST may have an effective diameter smaller than that of the nth lens, and the effective diameter of the lens adjacent to the object side of the aperture stop ST may be larger than that of the lens adjacent to the sensor side of the aperture stop. The effective diameter of the lens adjacent to the sensor side of the aperture stop ST may be the minimum effective diameter. In this way, by reducing the effective diameters of the lenses adjacent to the aperture stop ST, a slim optical system can be provided. The center thickness of the lenses adjacent to the object side and sensor side of the aperture stop ST can be thinner than that of the n-1th lens and the n-2th lens, thereby reducing TTL. In addition, the center thickness of the first lens in the optical system can be thinner than that of the last lens, thereby increasing the refractive angle according to the maximum sag value. By controlling the effective diameter and sag value of each lens, it is possible to control the light incident on the image sensor 300 having at least 2 megabytes of pixels, compensate for the degradation of optical characteristics due to resolution and temperature changes within the optical system, improve chromatic aberration control characteristics, and improve the vignetting characteristics of the optical system 1000.

[0044] On a lens surface disposed between the object and the aperture ST, the effective diameter of the lens surface tends to decrease as it moves from the object side to the aperture ST. On a lens surface disposed between the aperture ST and the image sensor 300, the effective diameter of the lens surface tends to increase as it moves from the aperture ST to the sensor side. The meaning of "the effective diameter of the lens tends to increase as it moves from the aperture ST to the sensor side" can include a lens surface disposed between the aperture ST and the image sensor 300, where the effective diameter of the lens surface gradually increases or decreases as it moves from the aperture ST to the sensor side.

[0045] The aperture ST may be arranged around the object-side surface of the lens closest to the object among the lenses in the second lens group LG2. Alternatively, the aperture ST may be arranged around the sensor-side surface of the lens closest to the object. Alternatively, at least one lens selected from the plurality of lenses may function as an aperture. More specifically, the object-side or sensor-side surface of one lens selected from the lenses of the optical system 1000 may function as an aperture to adjust the amount of light.

[0046] The optical axial distance between the first lens group LG1 and the second lens group LG2 may be the optical axial distance between the sensor-side surface of the first lens group LG1 and the object-side surface of the second lens group LG2. The optical axial distance between the first lens group LG1 and the second lens group LG2 may be the center-to-center distance between an aspherical lens and a spherical lens, or may be larger than the center-to-center distance between the spherical lenses. The optical axial distance between the first lens group LG1 and the second lens group LG2 may be more than 1 time the optical axial distance of the first lens group LG1, for example, in the range of 2 to 3 times the optical axial distance of the first lens group LG1. The optical axial distance between the first lens group LG1 and the second lens group LG2 may be less than 0.3 times the optical axial distance of the second lens group LG2, for example, more than 0 times but less than 0.3 times. The optical axial distance of the first lens group LG1 is the optical axial distance from the object-side surface of the first lens to the sensor-side surface. The optical axial distance of the second lens group LG2 is the optical axial distance between the object-side surface of the lens closest to the object side of the second lens group LG2 and the sensor-side surface of the lens closest to the image sensor 300. Here, the first lens group LG1 may include a lens positioned closer to the object than the aperture stop ST, and the second lens group LG2 may include a lens positioned closer to the sensor than the aperture stop ST. The first lens group LG1 and the second lens group LG2 may be divided into an object-side lens group and a sensor-side lens group based on the aperture stop ST. The sensor-side surface of the first lens group LG1 may have a concave shape with respect to the optical axis, and the object-side surface of the second lens group LG2 may have a convex shape with respect to the optical axis, and they may face each other.

[0047] The first lens group LG1 has a negative (-) power, and the second lens group LG2 can have a positive (+) power. The lens closest to the object side among the first lens group LG1 has a positive (+) power, and the lens closest to the sensor side among the lenses of the second lens group LG2 can have a negative (-) power. When the absolute value of the focal length of the first lens group LG1 is F_LG1 and the absolute value of the focal length of the second lens group LG2 is F_LG2, F_LG2 < F_LG1 can be satisfied. Here, when the combined focal length of the first lens 101 and the second lens 102 in the optical system 1000 is F12 and the combined focal length of the third lens 103 to the fourth lens 104 is F34, the condition F12 < F34 can be satisfied, and the conditions F13, F47 > 0 can be satisfied. Also, the conditions F_LG1 < F12 < F_LG2 and F_LG1 < F34 < F_LG2 can be satisfied. Here, F_LG1 is the focal length of the first lens 101 and can be defined as F1, and F_LG2 is the combined focal length of the second lens 102 to the fourth lens 104 and can be defined as F24. Also, the number of lenses having a negative (-) power in the optical system 1000 may be more than the number of lenses having a positive (+) power. The number of lenses having a negative (-) power may exceed 50% compared to the total number of lenses, and for example, can be in the range of 51% to 70%.

[0048] The lens unit 100 can mix spherical lenses and aspherical lenses. The average effective diameter of the aspherical lens may be smaller than the average effective diameter of the spherical lens. The average effective diameter of the aspherical lens surface may be smaller than the average effective diameter of the spherical lens surface. Also, the difference between the average effective diameter of the aspherical lens and the average effective diameter of the spherical lens can be 0.3 mm or more, and for example, can be in the range of 0.3 mm to 1.6 mm. Thereby, when at least one aspherical lens is arranged in the camera module, the weight of the camera module can be reduced, and the distortion in the peripheral part can be reduced. Also, the reduction in assembly property can be prevented by reducing the difference in the effective diameter between the aspherical lens and the spherical lens.

[0049] The first lens group LG1 refracts light incident through the object side in the optical axis direction, and the second lens group LG2 refracts light emitted through the first lens group LG1 to the periphery of the image sensor 300. The optical axis distance between the first lens group LG1 and the second lens group LG2 may be 0.8 mm or more, for example, 2 mm or less.

[0050] The average Abbe number of the spherical lenses in the lens unit 100 may be smaller than the average Abbe number of the aspherical lenses. The lens closest to the object has a high Abbe number and a low refractive index, which can suppress chromatic dispersion of incident light in an optical system with a small TTL, thereby achieving a wider angle of view compared to the focal length. In an embodiment, the sum of the refractive indices of the lenses in the lens unit 100 may be 10 or less, for example, in the range of 6 to 10, and the average of the refractive indices may be in the range of 1.58 to 1.68. The sum of the Abbe numbers of the lenses may be 220 or more, for example, in the range of 220 to 320, and the average of the Abbe numbers may be 49 or more, for example, in the range of 49 to 59. The sum of the center thickness of all the lenses may be 6 mm or less, for example, in the range of 3 mm to 6 mm or 4 mm to 6 mm. The average center thickness of all the lenses may be 1.5 mm or less, for example, in the range of 0.8 mm to 1.5 mm. The sum of the center-to-center distances between the lenses on the optical axis OA is 3.6 mm or more, for example, in the range of 3.6 mm to 4.6 mm or 4.1 mm to 5.1 mm, and may be smaller than the sum of the center thicknesses of the lenses. Furthermore, the average effective diameter of each lens surface of the lens unit 100 may be 5 mm or less, for example, in the range of 2 mm to 5 mm or 3 mm to 5 mm. The difference between the maximum and minimum effective diameters may be 4 mm or less. This makes it possible to provide an optical system with a small difference in the effective diameter of each lens, improving the ease of assembly of the lenses assembled within the lens barrel.

[0051] When the number of aspherical lenses within the lens unit 100 is Ma, the number of lenses having an effective diameter smaller than the diagonal length of the image sensor 300 is Mb, and the number of lenses having a negative power is Mc, the condition Mb < (= including, less than or equal to) Ma < Mc can be satisfied, and preferably the condition is Mb < Ma. When the number of lens surfaces having an aspherical surface within the lens unit 100 is Ma1, the number of lens surfaces having an effective diameter smaller than the diagonal length of the image sensor 300 is Mb1, and the number of lenses having a negative power is Mc, the condition Mb1 < (= including, less than or equal to) Ma1 < Mc can be satisfied, and preferably the condition is Mb1 < Ma1. The lens surfaces are the object side surface and the sensor side surface of each lens. When the number of spherical lenses within the lens unit 100 is Ga, the number of lenses having an effective diameter smaller than the diagonal length of the image sensor 300 is Gb, and the number of lenses having a positive power is Gc, the condition Gc < Ga < (= including, less than or equal to) Gc can be satisfied, and preferably the condition is Ga < Gc.

[0052] The F-number of the optical system or camera module according to the embodiments of the invention may be 2.4 or less, for example, in the range of 1.4 to 2.4 or 1.8 to 2.3. The maximum angle of view (diagonal) of the optical system according to the embodiments of the invention may be less than 85 degrees, for example, more than 45 degrees and less than 85 degrees, or in the range of 50 degrees to 80 degrees. The horizontal angle of view FOV_H in the Y-axis direction of the optical system for a vehicle may be more than 40 degrees and less than 60 degrees, for example, in the range of 45 degrees to 59 degrees. The horizontal angle of view FOV_H is the angle of view based on the horizontal length of the sensor. This makes it possible to suppress changes in the focal position due to temperature changes, and to provide a vehicle camera in which various aberrations are well corrected. When the diagonal angle of view of the optical system 1000 is between 50 and 80 degrees, and the optical system includes at least one aspherical lens and at least three spherical lenses, the average center thickness of the spherical lenses can be made thicker than the average center thickness of the aspherical lenses. This allows the aspherical and spherical lenses made of glass to suppress changes in optical performance due to temperature changes from low to high temperatures.

[0053] The optical system 1000 or camera module may include an image sensor 300. The image sensor 300 may detect light and convert it into an electrical signal. The image sensor 300 may detect light that has sequentially passed through the lens unit 100. The image sensor 300 may include an element capable of detecting incident light, such as a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS). Here, the diagonal length of the image sensor 300 may be 95% or more of the maximum effective diameter of the lens, for example, in the range of 95% to 130%, and may be in the range of 104% to 124%.

[0054] The optical system 1000 or the camera module may include an optical filter 500. The optical filter 500 is disposed between the second lens group LG2 and the image sensor 300. The optical filter 500 is disposed between the lens of the lens unit 100 closest to the sensor and the image sensor 300. For example, the optical system 100 may be disposed between the last lens and the image sensor 300. A cover glass 400 is disposed between the optical filter 500 and the image sensor 300 to protect the upper part of the image sensor 192 and prevent a decrease in reliability of the image sensor 192. The cover glass 400 may be removed. The optical filter 500 may include an infrared filter or an infrared cut-off filter (IR cut-off). The optical filter 500 may pass light in a predetermined wavelength band and filter out light in a different wavelength band. If the optical filter 500 includes an infrared filter, it may block radiant heat emitted from external light from being transmitted to the image sensor 300. The optical filter 500 can transmit visible light and reflect infrared light. The optical filter 500 can pass wavelengths of 920 nm or more, for example, a wavelength band of 920 nm to 960 nm.

[0055] Since the embodiment is an optical system applied to a vehicle camera, even if a design is made using both aspherical and spherical lenses, the first lens 101 may be made of glass. This is because glass has advantages over plastic in that it is more scratch-resistant and less sensitive to external temperatures. The first lens 101 has a shape that bulges from the interior of the vehicle toward the driver, which can more effectively prevent foreign matter from being deposited or scratched, thereby improving incidence efficiency. This can improve the reliability of the driver monitoring camera module. The optical system 1000 according to the embodiment may further include a reflective member (not shown) for changing the path of light. The reflective member may be implemented as a prism that reflects light incident on the first lens group LG1 toward the lens. The optical system according to the embodiment will now be described in detail.

[0056] An optical system according to an embodiment of the invention will now be described.

[0057] 1 to 3, an optical system 1000 according to an embodiment includes a lens unit 100, which may include a first lens 101 to a fifth lens 105. The first to fifth lenses 101, 102, 103, 104, and 105 are sequentially aligned along an optical axis OA. Light corresponding to object information passes through the first to fifth lenses 101 to 105 and an optical filter 500 and is incident on an image sensor 300. The first lens 101 is a lens in the first lens group LG1 and is the lens closest to the object side. The fifth lens 105 is a lens in the second lens group LG2 or the lens in the lens unit 100 that is closest to the image sensor 300. The second to fifth lenses 102, 103, 104, and 105 may be part of the second lens group LG2.

[0058] The composite focal lengths of the lenses, F12, F24, and F34, can satisfy the following conditions: F12 is the composite focal length of the first and second lenses, F34 is the composite focal length of the third and fourth lenses, and F25 is the composite focal length of the second to fifth lenses. The powers are the reciprocals of the focal lengths.

[0059] Condition 1: F25>0 Condition 2: F35>0 Condition 3: F12<0 Condition 4: F34>0 Condition 5: F35<|F12| Condition 6: F25<|F12| The first lens 101 may have positive (+) or negative (-) power on the optical axis OA. The first lens 101 may have negative (-) power. The first lens 101 may include a plastic material or a glass material, for example, a glass material. The glass first lens 101 can reduce changes in the center position and curvature radius due to temperature changes depending on the surrounding environment and can protect the incident side of the optical system 1000.

[0060] The first surface S1 of the first lens 101 on the object side may be convex and the second surface S2 on the sensor side may be concave relative to the optical axis. The first lens 101 may have a meniscus shape that bulges from the optical axis toward the object side. Alternatively, the first surface S1 may be concave and the second surface S2 may be convex relative to the optical axis OA. The first surface S1 and the second surface S2 of the first lens 101 may be aspherical relative to the optical axis, and the aspherical coefficients may be represented by L1S1 and L1S2 in FIG. 4. The first lens 101 is an aspherical lens made of glass, which can suppress movement of the optical axis and prevent degradation of optical performance when the temperature changes from low to high. In addition, the aspherical glass material can improve distortion at the periphery of the lens even when the lens is designed to be thin. Alternatively, when the first lens 101 is a spherical lens, it may have negative power.

[0061] The first lens 101 has a first surface S1 that is convex with respect to the optical axis and a second surface S2 that is concave, so that incident light can be refracted in a direction closer to the optical axis. This allows the edge distance between the first and second lenses 101 and 102 and the effective diameter of the second lens 102 to be reduced. The first lens 101 is disposed so that its edge thickness is thicker than its center thickness, so it is insensitive to assembly tolerances. Insensitive to assembly tolerances means that even if there is a slight deviation from the design during assembly, it does not significantly affect optical performance.

[0062] The aperture stop ST may be disposed around the space between the first lens 101 and the second lens 102. The aperture stop ST may be disposed around the object side surface of the second lens 102. The aperture stop ST may be disposed closer to the object side surface of the second lens 102 than to the sensor side surface of the first lens 101. Alternatively, the aperture stop ST may be disposed around the sensor side surface of the second lens 102 or around the object side surface of the first lens 101. Since the aperture stop ST is disposed around the space between the first and second lenses 101 and 102, the difference in effective diameter between the first and second lenses 101 and 102 can be reduced. The first lens 101 and the second lens 102 on either side of the aperture stop ST may have powers with the same sign. The difference in power between the first lens 101 and the second lens 102 on either side of the aperture stop ST may be 10% or less of the average power of both lenses.

[0063] The second lens 102 is disposed between the first lens 101 and the third lens 103. The second lens 102 may have positive (+) or negative (-) power on the optical axis OA. The second lens 102 may have negative (-) power. The second lens 102 may include plastic or glass. For example, the second lens 102 may be made of glass. The object-side third surface S3 of the second lens 102 may have a concave shape, and the sensor-side fourth surface S4 may have a convex shape relative to the optical axis OA. The second lens 102 may have a meniscus shape that bulges from the optical axis toward the sensor. Alternatively, the third surface S3 may have a convex shape, and the fourth surface S4 may have a concave shape. Alternatively, the second lens 102 may have a concave shape on both sides. The second lens 102 may be made of a spherical lens made of glass. The third surface S3 and the fourth surface S4 may be spherical. Because the second lens 102 is disposed closest to the sensor side of the aperture stop ST, the second lens 102 may have the smallest effective diameter among the first to fifth lenses 101-105. The center-to-center distance between the first and second lenses 101 and 102 is greater than the sum of the center thicknesses of the first and second lenses 101 and 102. The edge distance between the first and second lenses 101 and 102 may be smaller than the sum of the center thicknesses of the first and second lenses 101 and 102. Here, the edge distance is the optical axial distance between the end of the effective area on the sensor side of the object-side lens of the two adjacent lenses and the end of the effective area on the object-side of the sensor-side lens.

[0064] The effective diameters of the first and second lenses 101 and 102 disposed on the object side and sensor side of the aperture ST may be smaller than the effective diameters of the third to fifth lenses 103, 104, and 105. Furthermore, with regard to the effective diameters of the first and second lenses 101 and 102 adjacent to the aperture ST, the effective diameter of the second lens 102 closer to the aperture ST may be smaller than the effective diameter of the first lens 101, and the effective diameter of the first lens 101 may be smaller than the effective diameter of the third lens 103, among the third to fifth lenses 103, 104, and 105, which is adjacent to the aperture ST. When the aperture ST is disposed between the first and second lenses 101 and 102 to reduce TTL, the effective diameters of both lenses adjacent to the aperture ST may be designed to be smaller than the effective diameters of the other lenses. Furthermore, since the first and second lenses 101 and 102 have small effective diameters and thin central thicknesses, and the distance between the first and second lenses 101 and 102 is reduced, TTL can be reduced, but distortion and aberration of light traveling through the first and second lenses 101 and 102 may occur. Therefore, the first lens 101 can be provided as an aspherical lens to suppress the occurrence of distortion and aberration of light. Furthermore, distortion and aberration occurring to reduce TTL can be corrected by adjusting the refractive index, thickness, Abbe number, and radius of curvature of the third to fifth lenses 103, 104, and 105, as well as the distance between adjacent lenses. The power, distance, and thickness of the third and fourth lenses 103 and 104 to reduce distortion / aberration will be described later. If the aperture stop ST is located on the object side of the first lens 101, TTL can be further reduced, but this structure results in more severe aberration and distortion in the optical system, making it difficult to correct the aberration and distortion using other lenses, or increasing the TTL and increasing the size of the camera module.

[0065] The third lens 103 may have positive (+) or negative (-) power on the optical axis OA. The third lens 103 may have positive (+) power. The third lens 103 may be made of plastic or glass. For example, the third lens 103 may be made of glass. The power of the third lens 103 may be set to be at least twice the absolute value of the power of the first, second, and fifth lenses 101, 102, and 105 to correct distortion and aberration. The object-side fifth surface S5 of the third lens 103 may have a convex shape, and the sensor-side sixth surface S6 may have a convex shape relative to the optical axis. The third lens 103 may have convex surfaces on both sides of the optical axis. Alternatively, the third lens 103 may have a meniscus shape that bulges toward the sensor, or may have concave surfaces on both sides of the optical axis.

[0066] The third lens 103 may be a spherical lens made of glass. The central thickness of the third lens 103 may be two or three times the central thickness of the first and second lenses 101 and 102. Because the third lens 103 has convex shapes on both sides, the central thickness is greater than the edge thickness. The effective diameter of the third lens 103 may be greater than the effective diameters of the first and second lenses 101 and 102. Because the object side surface of the third lens 103 is convex on the optical axis and the sensor side surface of the second lens 102 is convex, the center distance between the second and third lenses 102 and 103 is the smallest among the center distances of the lenses.

[0067] The fourth lens 104 may have positive (+) or negative (-) power on the optical axis OA. The fourth lens 104 may have positive (+) power. The fourth lens 104 may be made of plastic or glass. For example, the fourth lens 104 may be made of glass. The power of the fourth lens 104 may be set to be at least twice the absolute value of the power of the first, second, and fifth lenses 101, 102, and 105 to correct distortion and aberration. The seventh surface S7 of the fourth lens 104 on the object side may have a convex shape, and the eighth surface S8 on the sensor side may have a convex shape based on the optical axis. The fourth lens 104 may have a shape that bulges on both sides of the optical axis. Alternatively, the fourth lens 104 may have a meniscus shape that bulges toward the sensor side or a concave shape on both sides. The fourth lens 104 may be a spherical lens made of glass. At least one of the seventh surface S7 and the eighth surface S8 of the fourth lens 104 is provided without a critical point. The fourth lens 104 may be the (n-1)th lens and may have the largest effective diameter among the lenses. The central thickness of the fourth lens 104 may be at least two or three times the central thickness of the first and second lenses 101 and 102. The central thickness of the third and fourth lenses 103 and 104 may be at least two or three times the minimum central thickness of the lenses.

[0068] Because the sensor side of the third lens 103 has a convex shape toward the optical axis and the object side of the fourth lens 104 has a convex shape toward the optical axis, the center distance between the third and fourth lenses 103 and 104 is greater than the sum of the center thicknesses of the first and second lenses 101 and 102. In addition, the edge distance between the third and fourth lenses 103 and 104 may be greater than the center distance between the third and fourth lenses 103 and 104. This is because the sensor side of the third lens 103 has a radius of curvature smaller than the radius of curvature of the object side and is provided in a convex curved shape, so the third lens 103 can refract light to the periphery of the fourth lens 104, which has the maximum effective diameter. Because the fourth lens 104 has a convex shape on both sides, the center thickness is greater than the edge thickness. The difference in absolute value between the radius of curvature of the object-side surface of the fourth lens 104 and the radius of curvature of the sensor-side surface may be smaller than the difference in absolute value between the radius of curvature of the object-side surface of the third lens 103 and the radius of curvature of the sensor-side surface. The difference in absolute value between the radius of curvature of the object-side surface of the fourth lens 104 and the radius of curvature of the sensor-side surface may be the smallest among the lenses. The third and fourth lenses 103 and 104, which are arranged consecutively along the optical axis, may each have a power that is at least twice the absolute value of the power of the first, second, and fifth lenses 101, 102, and 105, thereby correcting distortion and aberration occurring in the first and second lenses 101 and 102. Of the third and fourth lenses 103 and 104, the third lens 103, which is adjacent to the first and second lenses 101 and 102, may have the largest power.

[0069] In order to correct distortion and aberration caused by the first and second lenses 101 and 102, the center distance between the second and third lenses 102 and 103 may be reduced, and the center thickness of the third and fourth lenses 103 and 104 may be made thicker than the other lenses, and the center distance between the third and fourth lenses 103 and 104 may be set larger than the center distance between the first and second lenses 101 and 102. Such third and fourth lenses 103 and 104 may correct distortion and aberration of light passing through the first and second lenses 101 and 102 to be eliminated, and then refract the light to the entire area of ​​the fifth lens 105.

[0070] The fifth lens 105 may have positive (+) or negative (-) power on the optical axis OA. The fifth lens 104 may have negative (-) power. The fifth lens 105 may be made of plastic or glass. For example, the fifth lens 105 may be made of glass. The ninth surface S9 of the fifth lens 105 on the object side may be concave, and the tenth surface S10 of the fifth lens 105 on the sensor side may be convex relative to the optical axis. The fifth lens 105 may have a shape that convex from the optical axis toward the sensor. Alternatively, the fifth lens 105 may have a meniscus shape that convex from the optical axis toward the object side, or may have a concave shape on both sides. The fifth lens 105 may be a spherical lens made of glass. At least one of the ninth surface S9 and the tenth surface S10 of the fifth lens 105 is provided without a critical point. The fifth lens 105 may be the nth lens and may have the second largest effective diameter among the lenses. The central thickness of the fifth lens 105 may be ½ or less or ⅓ or less of the central thickness of the third and fourth lenses 103 and 104. The central thickness of the fifth lens 105 may have a difference of 10% or less from the central thickness of the first and second lenses 101 and 102. The fifth lens 105 is disposed so that its edge thickness is thicker than its central thickness, and can refract light to the entire area of ​​the image sensor 300 through its peripheral portion.

[0071] Because the sensor side surface of the fourth lens 104 has a convex shape toward the optical axis and the object side surface of the fifth lens 105 has a concave shape toward the optical axis, the center distance between the fourth and fifth lenses 104 and 105 may be the largest among the center distances between the lenses. Furthermore, the edge distance between the fourth and fifth lenses 104 and 105 may be smaller than the center distance. The fifth lens 105 may be a spherical lens closest to the image sensor 300. By positioning a spherical lens as the lens closest to the image sensor 300, assembly is improved compared to an aspherical lens. The object side surface of the fifth lens 105 has a curved shape with an edge adjacent to the end of the effective area of ​​the fourth lens 104 and a concave center, allowing light refracted by the fourth lens 104 to be incident thereon. This maximizes the center distance between the fifth lens 105 and the fourth lens 104, thereby preventing an increase in the effective diameter of the fifth lens 105. In addition, since the sensor side of the fifth lens 105 has a convex curved shape, it is possible to refract light to the entire area of ​​the image sensor 300 without having an aspherical surface. As another example, the fifth lens 105 may be a glass lens having an aspherical surface.

[0072] Referring to FIG. 2, at least one of the ninth surface S9 and the tenth surface S10 of the fifth lens 105 is provided without a critical point. The critical point is the point at which the trend of the sag value changes. That is, the point at which the sag value decreases while increasing, or the point at which the sag value increases while decreasing. The sag value is the optical axis distance between the lens surface and a line perpendicular to the center of each lens surface. The sag value has a positive value at a position located closer to the sensor than the center of each lens surface and a negative value at a position located closer to the object than the center of each lens surface. In terms of absolute sag values, the maximum value of Sag51 may be greater than the maximum values ​​of Sag41, Sag42, and Sag52. Sag51 is the optical axial distance from a line perpendicular to the center of the object side surface of the fifth lens 105 to the object side surface of the fifth lens 105, Sag41 is the optical axial distance from a line perpendicular to the center of the object side surface of the fourth lens 104 to the object side surface, Sag42 is the optical axial distance from a line perpendicular to the center of the sensor side surface of the fourth lens 104 to the sensor side surface, and Sag52 is the optical axial distance from a line perpendicular to the center of the sensor side surface of the fifth lens 105 to the sensor side surface of the fifth lens 105.

[0073] The sag values ​​of the seventh object-side surface S7 and the eighth sensor-side surface S8 of the fourth lens 104 may have different signs and a difference of less than 0.2 mm. For example, the sag values ​​of the seventh and eighth surfaces S7 and S8 may be less than 0.2 mm at 0.1 mm, 0.2 mm, 1 mm, 2 mm, or 3 mm on the optical axis, or at the end or edge. The absolute values ​​of the sag values ​​of the seventh and eighth surfaces S8 of the fourth lens 104 may differ by less than 0.2 mm at a distance D1 half the effective radius on the optical axis. The absolute values ​​of the sag values ​​of the seventh and eighth surfaces S8 may gradually increase toward the edge on the optical axis and may have the same value at the same distance from the optical axis. The back focal length (BFL) is the distance from the image sensor 300 to the center of the sensor side of the last lens. The BFL may be 1.5 mm or more, ensuring installation space for the optical filter 500 or the optical filter 500 and the cover glass 400. CT4 is the center thickness or optical axis thickness of the fourth lens 104, and ET4 is the edge thickness of the fourth lens 104. CT5 is the center thickness or optical axis thickness of the fifth lens 105, and ET5 is the edge thickness of the fifth lens 105. The edge thickness is the distance in the optical axis direction from the end of the effective area of ​​each lens to the object side surface and the sensor side surface. CG4 is the optical axis distance from the center of the sensor side surface of the fourth lens 104 to the center of the object side surface of the fifth lens 105 (i.e., center-to-center spacing). In other words, CG4 is the distance from the center of the eighth surface S8 to the center of the ninth surface S9. EG4 is the distance in the optical axis direction from the edge of the sensor side surface of the fourth lens 104 to the edge of the object side surface of the fifth lens 105 (i.e., edge spacing).

[0074] In the optical system 1000, at least one lens having an aspherical surface has an effective diameter smaller than the average effective diameter of the spherical lenses and is positioned closest to the object side, allowing light to be guided to the entire area of ​​the image sensor using a lens system with a small number of lenses. A first lens 101 is positioned on the object side of the aperture stop ST, and a second lens 102, a third lens 103, and fourth and fifth lenses 104 and 105 are positioned on the sensor side of the aperture stop ST. Here, the effective diameters of the first lens 101 to the fifth lens 105 can be defined as CA1, CA2, CA3, CA4, and CA5, and the effective diameters of the object-side and sensor-side surfaces of the first lens 101 to the fifth lens 105 can be defined as CA11, CA12, CA21, CA22, CA31, CA32, CA41, CA42, CA51, and CA52. When the aperture stop ST is positioned on the object-side surface of the second lens 102, the following condition can be satisfied:

[0075] Condition 1: CA2 <CA1<CA3<CA4<CA5 Condition 2: (CA4-CA5)<(CA1-CA2) Condition 3: CA2 <ImgH<CA4<(2×ImgH) Condition 4: CA21 <CA11<CA32<CA42 Condition 5: CA51 <CA41<CA52 The second lens 102, located on the sensor side of the aperture ST, has negative power (F2<0), so the second lens 102 can refract incident light. Furthermore, the third lens 103 has convex surfaces on both sides, so it can refract light toward the edge of the fourth lens. This prevents a decrease in the yield by weight of the optical system due to the second and third lenses 102 and 103, and improves production efficiency. The composite focal length of the second to fifth lenses 102-105, located on the sensor side of the aperture ST, can have a positive value, so that TTL can be reduced within the angle of view.

[0076] The distance between the first lens 101 and the second lens 102 may gradually decrease from the center to the edge. The distance between the second lens 102 and the third lens 103 may gradually increase from the center to the edge. This distance may gradually increase from the optical axis to the edge because the sensor side of the second lens 102 is convex and the object side of the third lens 103 is convex.

[0077] FIG. 3 shows an example of lens data for the optical system of the embodiment shown in FIG. 3. As shown in FIG. 3, the radius of curvature of the first through fifth lenses 101, 102, 103, 104, and 105 along the optical axis OA, the lens center thickness CT, the center distance CG between adjacent lenses, the refractive index at the d-line, the Abbe number, and the effective radius (semi-aperture) can be set. Expressing the radius of curvature of each lens along the optical axis as an absolute value, the radius of curvature of each of the first through fifth lenses 101-105 along the optical axis OA can be 30 mm or less, for example, in the range of 1 mm to 30 mm or 1 mm to 20 mm. Furthermore, the difference between the radii of curvature of adjacent lens surfaces can be less than 30 mm, for example, in the range of 0.1 mm to 25 mm or 0.1 mm to 15 mm. This allows light to be guided without increasing the difference in the radii of curvature of the optical system 1000, which has six or fewer lenses. In absolute values, the difference in the radii of curvature between the first and second surfaces S1 and S2 may be 5 mm or less, the difference in the radii of curvature between the second and third surfaces S2 and S4 may be 3 mm or less, the difference in the radii of curvature between the third and fourth surfaces S3 and S4 may be 5 mm or less, the difference in the radii of curvature between the fourth and fifth surfaces S4 and S5 may be 15 mm or less, the difference in the radii of curvature between the fifth and sixth surfaces S6 and S6 may be 15 mm or less, the difference in the radii of curvature between the sixth and seventh surfaces S6 and S7 may be 15 mm or less, the difference in the radii of curvature between the seventh and eighth surfaces S7 and S8 may be 1 mm or less, the difference in the radii of curvature between the seventh and ninth surfaces S8 and S9 may be 15 mm or less, and the difference in the radii of curvature between the ninth and tenth surfaces S9 and S10 may be 15 mm or less. Here, the radii of curvature of the glass lenses may be 5% or more of the effective radius, for example, in the range of 5% to 95%.

[0078] When the radius of curvature of each lens is expressed as an absolute value on the optical axis, the radius of curvature of the fifth surface S5 of the third lens 103 may be the largest among the lenses. Either the radius of curvature of the second surface S2 of the first lens 101 or the third surface S3 of the second lens 102 may be the smallest among the lenses. The maximum radius of curvature may be less than 30 mm, for example, 25 mm or less, and may be 15 times or less, for example, in the range of 5 to 15 times, the minimum radius of curvature. The radius of curvature of the first lens 101, which is an aspherical lens, may be smaller than the radius of curvature of at least one or all of the second through fifth lenses 102-105, which are made of spherical materials. Here, the radius of curvature is the average of the absolute values ​​of the radius of curvature of the object-side and sensor-side surfaces of each lens.

[0079] In terms of absolute values, the radius of curvature of the first lens 101 disposed on the object side of the aperture stop ST along the optical axis may be smaller than the radius of curvature of the second lens 102 disposed on the sensor side of the aperture stop ST. In terms of absolute values, the radius of curvature of the fourth lens 104 may be larger than the radius of curvature of the third lens 103 along the optical axis. In terms of absolute values, the difference between the radii of curvature of the object-side surface and the sensor-side surface of the third lens 103 may be larger than the difference between the radii of curvature of the object-side surface and the sensor-side surface of the fourth lens 104, and may be larger than the difference between the radii of curvature of the object-side surface and the sensor-side surface of the fifth lens 105. The difference between the radii of curvature of the object-side surface and the sensor-side surface of the third lens 103 may be the largest of the differences between the radii of curvature of the object-side surface and the sensor-side surface of each lens.

[0080] If the first lens 101 is designed with an aspherical surface made of glass, it can satisfy thermal compensation and improve optical performance, but it is more difficult to assemble than a spherical lens, and the assembly of the aspherical first lens 101 may affect the optical characteristics of lenses located closer to the sensor than the first lens 101. If the first lens were a spherical lens, even if the optical characteristics of the first lens were affected, the radius of curvature of the first lens would not be significantly changed by the spherical characteristics. In this invention, the radius of curvature of the aspherical first lens 101 is designed to be 10 mm or less and a small effective diameter, making assembly easier. Even if the lens is assembled with a slight tilt from the optical axis, the impact on the sensor-side lens is minimal. By providing the third through fifth lenses 103-105 with spherical surfaces, the difference in the radius of curvature between the object-side and sensor-side surfaces can be reduced, and the large effective diameter improves assembly and reduces the impact on optical characteristics.

[0081] The radii of curvature of the first and second surfaces S1 and S2 of the first lens 101 are defined as L1R1 and L1R2, the radii of curvature of the ninth and tenth surfaces S9 and S10 of the fifth lens 105 are defined as L5R1 and L5R2, and the radii of curvature of the second, third, and fourth lenses 102, 103, and 104 are defined as L2R1, L2R2, L3R1, L3R2, L4R1, and L4R2. The ratios of the radii of curvature of the object side surface and the sensor side surface of each lens are as follows:

[0082] Condition 1:1 <L1R1 / L1R2<3 Condition 2:0 <L2R1 / L2R2<1 Condition 3: 1.2 < |L3R1 / L3R2| < 5 (where L3R1 > 0, L3R2 < 0) Condition 4: 0.5<|L4R1 / L4R2|<1.5 Condition 5:0<|L5R1 / L5R2|<1 Condition 6: 0mm < (including =, less than or equal to) |L4R1| - |L4R2| < (including =, less than or equal to) 1mm Preferably, Condition 5 satisfies |L4R1|-L4R2<(including =, less than or equal to) 0.2 mm. Preferably, the absolute value of L4R1 and L4R2 are equal to each other or have a difference within the tolerance of the radius of curvature. The tolerance of the radius of curvature may be ±0.05 mm. If the difference in the radius of curvature between the seventh object-side surface S7 and the eighth sensor-side surface S8 of the fourth lens 104 is designed to be within the above range or tolerance, the object-side surface and the sensor-side surface can be assembled without separating them, improving assembly convenience. If the difference in the radius of curvature between the seventh object-side surface S7 and the eighth sensor-side surface S8 of the fourth lens 104 exceeds 0.2 mm, it may be difficult to separate the lens surfaces S7 and S8, resulting in a problem of assembly being reversed.

[0083] Furthermore, if the absolute value of the radius of curvature of the object-side surface of the i-th lens is LiR1 and the absolute value of the radius of curvature of the sensor-side surface is LiR2, the value of LiR1 / LiR2 (i = 1 to 5) is maximum when i is 1 and minimum when i is 5. Furthermore, the difference in the radii of curvature between adjacent aspherical and spherical lens surfaces can satisfy the following condition:

[0084] Condition 7: 0.5<|L1R2| / L2R1<1.4 The difference in the radius of curvature between such a spherical lens surface and an aspherical lens surface is set to 1 mm or less, for example, in the range of 0.1 mm to 1 mm, so that chromatic aberration between the lens surfaces can be corrected.

[0085] If the center thicknesses of the first through fifth lenses 101-105 are defined as CT1-CT5 and the edge thicknesses of the first through fifth lenses 101-105 are defined as ET1-ET5, the sum of the center thicknesses of the first through fifth lenses 101-105 can be defined as ΣCT, and the sum of the edge thicknesses of the first through fifth lenses 101-105 can be defined as ΣET. Regarding lens thickness, the center thickness CT4 of the fourth lens 104 is greater than the center thicknesses CT1, CT2, and CT5 of the first, second, and fifth lenses 101, 102, and 105, and preferably has the greatest thickness among the lenses. Because the center thickness CT4 of the fourth lens 104 is the largest and the radius of curvature of the sensor side surface is the largest among the radii of curvature of the sensor side surfaces of the lenses, incident light can be refracted to the end of the effective area of ​​the last lens. That is, in order to adjust the optical path according to the TTL of 20 mm or less and the effective diameter and lens shape of the fourth lens 104, the fifth lens 105 can have a meniscus shape that bulges toward the sensor side.

[0086] The ratio of the center thickness to the edge thickness of each lens can satisfy the following condition:

[0087] Condition 1:0 <CT1 / ET1<1 Condition 2:0 <CT2 / ET2<1 Condition 3: 0.5 <CT3 / ET3<1.5 Condition 4:0.1 <CT4 / ET4<1.1 Condition 5:0 <CT4 / ET4<1 Condition 6: 0.1<ΣCT / ΣET<1.1 or 0.3<ΣCT / ΣET<1 Condition 7: CT1 / ΣCT<0.3 Condition 8:0.15 <CT4 / ΣCT<0.7 Under the above conditions, when CTi / ETi (i=1 to 5), it is maximum when i is 3 and minimum when i is 1. The difference between the center thickness and edge thickness of each lens can be set to more than 0.01 mm and less than 2 mm. In addition, by disposing an aspherical lens in the first lens 101 and designing it so that the ratio of the center thickness to the edge thickness is the largest, it is possible to prevent a decrease in ease of assembly due to the aspherical lens.

[0088] In order to provide the thickness of the edges of the third and fourth lenses 103 and 104 to be 0.6 mm or more, the center thicknesses of the third and fourth lenses 103 and 104 can be set thick, and the radii of curvature of the object side surface and the sensor side surface can be set large. By setting the difference between the center thickness and the edge thickness of the fourth lens 104 within the range of condition 4, it is not necessary to greatly design the difference in the radii of curvature of the object side surface and the sensor side surface, and the assembly property of the fourth lens 104 can be improved. Also, the difference between the maximum center thickness and the minimum center thickness in the lens can be 2 mm or less, for example, it can have a range of 0.5 mm to 2 mm or 1 mm to 1.5 mm. That is, even if the center thickness of the last spherical lens is provided thin, a decrease in optical performance does not occur, and the thickness of the camera module can be provided slim. Also, since the difference between the center thickness and the edge thickness of each lens is made small, even if at least one lens tilts, the influence on the optical characteristics can be reduced. Also, the influence on the thermal characteristics between the center part and the edge part of each lens can be reduced by the glass lens.

[0089] The maximum center thickness is greater than the sum of the center thicknesses of two different lenses. For example, conditions: (CT1 + CT2) < CT4, (CT1 + CT5) < CT4, and (CT2 + CT5) < CT4 can be satisfied. The center thickness of the third lens 103 is greater than the sum of the center thicknesses of two different lenses. For example, conditions: (CT1 + CT2) < CT3, (CT1 + CT5) < CT3, and (CT2 + CT5) < CT3 can be satisfied.

[0090] The center-to-center distances between the first to fifth lenses 101-105 are defined as CG1-CG4, and the sum of the center-to-center distances between the first to fifth lenses 101-105 can be defined as ΣCG. The center-to-center distances between adjacent lenses among the second lens 102-fifth lens 105 are CG2, CG3, and CG4, which are the center-to-center distances between spherical lenses. The center-to-center distance between the first and second lenses 101 and 102 is CG1, which is the center-to-center distance between the spherical lens and the aspherical lens. The center-to-center distance CG4 between the fourth and fifth lenses 104 and 105 is the maximum within the lens unit 100 and may be larger than the center-to-center distance between the aspherical lens and the spherical lens. The relationship between the center thickness of each lens and the center-to-center distance between adjacent lenses may satisfy the following condition:

[0091] Condition 1:0 <CT1 / CG1<1 Condition 2:1.5 <CT2 / CG2<4 Condition 3:1 <CT3 / CG3<2 Condition 4:0.5 <CT4 / CG4<1.5 Condition 5:0 <CT5 / CG4<1 Condition 6: (CT1 / CG1)<(CT4 / CG4)<(CT3 / CG3) Condition 7:0 <CG3 / ΣCG<0.5 Condition 8:0.5 <CT_Max / CG_Max<1.5 By providing the maximum center-to-center thickness between lenses to be at least twice the maximum center-to-center distance, for example, in the range of 2.1 to 4.5 times, a camera module using aspherical lenses in an optical system can be provided without increasing the center thickness compared to the center-to-center distance between each lens. According to condition 3, since the spherical third and fourth lenses 103 and 104 are provided with convex surfaces on both sides, the center-to-center distance between the third and fourth lenses 104 and 105 can be reduced. Here, if the i-th center-to-center distance between adjacent lenses is defined as CGi and the center thickness of the i-th lens disposed closer to the object than CGi is defined as CTi, the following condition can be satisfied: The ratio CTi / CGi is maximum when i is 2 and minimum when i is 1. The condition that the value of CTi / CGi is maximum when i is 2 can be implemented by different meniscus shapes of the spherical and aspherical lenses.

[0092] When the optical axis distance from the center of the object side surface of the first lens 101 to the surface of the image sensor 300 is TTL, the following conditions can be satisfied.

[0093] Condition 1: 0 < CT1 / TTL < 0.2 Preferably, Condition 1 can satisfy 0.05 ≤ CT1 / TTL ≤ 0.15. Since the first lens 101 is made of an aspherical lens glass material, an optical system that can satisfy thermal compensation due to temperature change with a thickness that satisfies Condition 1 can be designed. That is, Condition 1 is a characteristic that appears when the first lens 101 is designed with an aspherical glass.

[0094] Condition 2: 0 < CT2 / TTL ≤ 0.15 Condition 3: 0.15 < CT3 / TTL < 0.5 Condition 4: 0.1 < CT4 / TTL < 0.3 Condition 5: 0 < CT5 / TTL ≤ 0.15 The ratio of CT1 / TTL in Conditions 3 and 4 may be larger than the values of Conditions 1, 2, and 5.

[0095] Regarding the refractive index, the third lens 103 has the highest refractive index among the lenses. Preferably, the refractive index of the third and fourth lenses 103 and 104 may be 1.7 or higher. The difference in refractive index between the third and fourth lenses 103 and 104 is 0.20 or less. When the refractive index of the third and fourth lenses 103 and 104 is higher than the refractive index of the first, second, and fifth lenses 101, 102, and 105, the power of the third and fourth lenses 103 and 104 can be increased, thereby preventing an increase in the radius of curvature of the object-side and sensor-side surfaces. This reduces the sensitivity of light traveling through the third and fourth lenses 103 and 104. The refractive index of the third and fourth lenses 103 and 104 may be higher than the average of the refractive indexes of the first to fifth lenses 101-105. The refractive index of the first, second, and fifth lenses 101, 102, and 105 may be less than 1.6. The refractive indexes of the first to fifth lenses 101-105 can be set to adjust chromatic dispersion. The third and fourth lenses 103 and 104 have thicker center and edge thicknesses than the other lenses, which can prevent the radii of curvature of the object side and sensor side of the third and fourth lenses 103 and 104 from increasing. The high refractive indexes of the third and fourth lenses 103 and 104 and thinner edge thicknesses than the center thickness can increase chromatic dispersion. The first lens 101 has a shape in which the object side surface protrudes toward the driver, which can increase the amount of incident light.

[0096] Regarding Abbe numbers, the Abbe numbers of at least one or all of the first, second, and fifth lenses 101, 102, and 105 may be the largest among the lenses and may be 55 or greater. The Abbe number of the third lens 103 is the smallest among the lenses. The difference between the largest and smallest Abbe numbers may be 20 or greater. Reducing the difference in Abbe numbers or refractive index between the object-side lens and the sensor-side lens of the aperture ST facilitates control of the path of light passing through the aperture ST. By providing a higher Abbe number for the fifth lens 105, which is closest to the image sensor 300, than the first lens 101, it is possible to adjust the chromatic dispersion of light traveling between the glass lenses and guide it to the image sensor 300.

[0097] The focal lengths F3 and F4 of the third and fourth lenses 103 and 104 may have positive power, and the focal lengths F1, F2, and F5 of the first, second, and fifth lenses 101, 102, and 105 may have negative power. Lenses repeatedly contract and expand as temperatures change from low to high. The amount of contraction and expansion can be reduced by using glass lenses. In terms of absolute focal lengths, the focal length of the second lens 102 is the longest among the lenses and may be 10 mm or more. The focal length of the third lens 103 is the shortest among the lenses. The difference between the maximum and minimum focal lengths may be 5 mm or more. The above focal lengths enable the optical system to have improved MTF characteristics, aberration control characteristics, and resolution characteristics within a set angle of view range, and to have good optical performance at the periphery of the angle of view.

[0098] As shown in FIG. 4, in this embodiment, the lens surface of the first lens 101 of the lens unit 100 may include an aspherical surface having a 30th-order aspherical coefficient. For example, the first lens 101 may include a lens surface having a 30th-order aspherical coefficient. As described above, an aspherical surface having a 30th-order aspherical coefficient (a value other than "0") can significantly change the aspherical shape of the peripheral portion, thereby effectively correcting the optical performance of the peripheral portion of the field of view (FOV). As shown in FIG. 5, the thicknesses T1-T5 of the first to fifth lenses 101, 102, 103, 104, and 105 and the spacings G1-G4 between adjacent lenses can be set. The thicknesses T1-T5 of each lens can be expressed at intervals of 0.1 mm or more in the Y-axis direction perpendicular to the optical axis, and the spacings G1-G4 between each lens can be expressed at intervals of 0.1 mm or more.

[0099] 6, when the sag values ​​are explained from the optical axis to the ends of the effective areas of the fourth and fifth lenses, it can be seen that the absolute values ​​of the sag values ​​of L4S1 and L4S2, which are the object-side and sensor-side surfaces of the fourth lens 104, and the sag value of L5S2, which is the sensor-side surface of the fifth lens 105, are smaller than the sag value of L5S1, which is the object-side surface of the fifth lens 105. It can be seen that the absolute value of the sag data of L5S1 is more than twice the absolute value of the sag data of L4S1, L4S2, and L5S2.

[0100] Figures 7 to 9 are graphs showing the diffraction MTF (Modulation Transfer Function) at room temperature, low temperature, and high temperature for the optical system of Figure 1, which are graphs showing the luminance ratio (modulation) as a function of spatial frequency. As shown in Figures 7 to 9, in an embodiment of the invention, the deviation of MTF between room temperature and low or high temperature can be less than 10%, i.e., 7% or less. In Figures 7 to 9, the X axis represents the defocusing position and the Y axis represents MTF, measured from F1 to F11 in increments of 0.309 mm from 0.000 mm to 3.092 mm.

[0101] 10 to 12 are graphs showing aberration characteristics at room temperature, low temperature, and high temperature for the optical system of FIG. 1. The aberration graphs of FIGS. 10 to 12 are graphs in which spherical aberration, astigmatic field curves, and distortion are measured from left to right. In FIGS. 10 to 12, the X axis represents focal length (mm) and distortion (%), and the Y axis represents image height. The graphs for spherical aberration are for light in wavelength bands of approximately 920 nm, 940 nm, and 960 nm, while the graphs for astigmatism and distortion are for light in the wavelength band of approximately 940 nm. Regarding the aberrations in FIGS. 10 to 12, the closer the curves at room temperature, low temperature, and high temperature are to the Y axis, the better the aberration correction function. It can be seen that the measured values ​​for the optical system 1000 according to the embodiment are close to the Y axis in almost all regions. That is, the optical system 1000 according to the embodiment has improved resolving power and can have good optical performance not only in the center but also in the periphery of the field of view (FOV). Here, low temperature can be -20 degrees or less, for example, in the range of -20 to -40 degrees, normal temperature can be in the range of 22 degrees ± 5 degrees or in the range of 18 degrees to 27 degrees, and high temperature can be 85 degrees or more, for example, in the range of 85 degrees to 105 degrees. This shows that the decrease in luminance ratio (modulation) from low to high temperatures in Figures 10 to 12 is less than 10%, for example, 5% or less, or is almost unchanged.

[0102] Table 1 compares the changes in optical characteristics such as EFL, BFL, F-number, TTL, and diagonal FOV at room temperature, low temperature, and high temperature for the optical system of Example 1, and shows that the rate of change in optical characteristics at low temperature is 5% or less, for example 3% or less, of the rate of change in optical characteristics at room temperature as the reference, and that the rate of change in optical characteristics at low temperature is 5% or less, for example 3% or less, of the rate of change in optical characteristics at room temperature as the reference. [Table 1]

[0103] Therefore, as shown in Table 1, it can be seen that the change in optical characteristics due to the temperature change from low temperature to high temperature, for example, the change rate of the effective focal length EFL, TTL, BFL, F value (F#), and the change rate of the diagonal field of view FOV are 10% or less, that is, 5% or less, for example, in the range of 0 to 5%. This means that even if at least one or two or more aspherical lenses are used, it is designed so that temperature compensation for the aspherical lens is possible, and a decrease in the reliability of optical characteristics can be prevented. Also, it can be seen that even when changing from room temperature to low temperature or high temperature, the effective focal length, TTL, BFL, F value (F#), diagonal field of view FOV, etc. hardly change. The optical system of the embodiment disclosed above can effectively control aberration characteristics such as chromatic aberration and distortion aberration, and can have good optical performance not only at the center but also at the periphery of the field of view FOV.

[0104] The optical system 1000 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 1000 according to the embodiment can have improved optical characteristics. For example, when the optical system 1000 satisfies at least one mathematical formula, the optical system 1000 can effectively control aberration characteristics such as chromatic aberration and distortion aberration, and can have good optical performance not only at the center but also at the periphery of the field of view FOV. Also, the optical system 1000 can have improved resolution. Also, for the meaning of the thickness of the lens on the optical axis OA and the interval between adjacent lenses on the optical axis OA described in the mathematical formula, reference can be made to the embodiment disclosed above.

[0105] [Formula 1] 0.5 < CT1 / CT2 < 1.5 CT1 means the center thickness of the first lens 101, and CT2 means the center thickness of the second lens 102. Formula 1 can set the difference in the center thicknesses of the first and second lenses to be small, and can easily adjust the optical path of the optical system. Preferably, it can satisfy 0.8 < CT1 / CT2 < 1.2. The center thicknesses of the first lens 101 having an aspherical surface and the second lens 102 having a spherical surface can be set, and the optical performance at the center and periphery of the field of view FOV can be improved.

[0106] [Equation 2] (CT5 × CA5) < (CT3 × CA3) CT5 is the central thickness of the fifth lens 105, CA5 is the effective diameter of the fifth lens 105, CT3 is the central thickness of the third lens 103, and CA3 is the effective diameter of the third lens. The effective diameter is the average of the effective diameters of the object side and the sensor side of each lens. Preferably, the condition CA5 < CA3 can be satisfied. By setting the thickness and effective diameter of the third and fifth lenses, the optical system can improve aberration.

[0107] [Equation 3] Po1 < 0 In Equation 3, Po1 represents the power of the first lens 101 and is set to have an effective focal length F similar to TTL in the optical system for the performance of the optical system. Thereby, TTL > F can be satisfied, and for example, the condition 1 < TTL / F < 4 can be satisfied.

[0108] [Equation 4] |Po1 × 2| < (including =, less than or equal to) Po3<00​​​​​​​​​​​​Nd3 is the refractive index of the third lens 103 at the d-line. Formula 5 indicates that by increasing the refractive index of the third lens, factors affecting the reduction of third-order aberrations (Seidel aberrations) in the optical system can be adjusted, thereby slightly increasing the TTL and reducing potential aberrations. Formula 5 preferably satisfies 1.8<(including, less than or equal to) Nd3<(including, less than or equal to) 2.1. When the refractive index is designed below the lower limit of Formula 4, aberrations can be reduced and performance can be achieved. However, the power of the third lens 103 weakens, preventing efficient light collection and resulting in reduced optical system performance. When the refractive index is designed above the upper limit of Formula 4, it becomes difficult to obtain materials. Furthermore, when the refractive index of the third lens is designed below the lower limit of Formula 4, the radius of curvature of the third lens must be increased to increase the power of the third lens. This makes lens manufacturing more difficult, increases the defective rate of lenses, and reduces yield.

[0111] [Formula 5-1] 1.7<(including =, less than or equal)Nd4<2.2 Nd4 is the refractive index of the fourth lens 104 at the d-line. Formula 5 allows the refractive index of the fourth lens to be set high. Formula 5-1 preferably satisfies 1.8<(including =, less than or equal to) Nd4<(including =, less than or equal to) 2.1.

[0112] [Formula 5-2] 1.60<(=included, less than or equal to) Aver(Nd1:Nd7)<(=included, less than or equal to) 1.70 In Formula 5-2, Aver(Nd1:Nd7) is the average of the refractive index values ​​at the d-line of the first to fifth lenses. When the optical system 1000 according to the embodiment satisfies Formula 5-2, the optical system can set the resolving power and suppress the influence on TTL.

[0113] [Formula 6]40 <FOV_H<60 In Equation 6, FOV_H represents the horizontal angle of view, and the range of the vehicle optical system can be set. The horizontal angle of view can be set using an optical system of six or less lenses, including at least one aspherical lens and at least two or more spherical lenses. Equation 6 preferably satisfies 45<(including =, less than or equal to) FOV_H<(including =, less than or equal to) 58, or can satisfy the range of 55°±3°. When Equation 6 is satisfied, the rate of change in the effective focal length and the rate of change in the angle of view when the temperature changes from room temperature to high temperature can be set to 5% or less, for example, 0 to 5%. Furthermore, even if aspherical lenses and spherical lenses are mixed and used within optical system 1000, deterioration of optical characteristics can be prevented by temperature compensation of the glass lenses.

[0114] [Formula 7] L1R1>0 L1R1 represents the radius of curvature of the first surface S1 of the first lens 101 and is set to be greater than 0. When Equation 7 is satisfied, the shape of the optical system can be limited. The object-side surface of the first lens 101 has a shape that bulges from the optical axis toward the driver, thereby increasing the amount of incident light. Furthermore, since the condition L1R1×L1R2>0 is satisfied, the incident light can be refracted in a direction closer to the optical axis. As a result, in this embodiment, the effective diameter of the second lens can be made smaller than the effective diameter of the first lens.

[0115] [Formula 7-1] L2R1<0, L3R2<0, and L4R2<0 L2R1 is the radius of curvature of the object side surface of the second lens 102, L3R2 is the radius of curvature of the sensor side surface of the third lens 103, and L4R2 is the radius of curvature of the sensor side surface of the fourth lens. Since the first lens has a meniscus shape bulging toward the object side, and the third and fourth lenses have convex shapes on both sides, the incident light can be refracted from the second lens 102 with the smallest effective diameter to the effective region of the fourth lens with the largest effective diameter. Since the first lens has a meniscus shape bulging toward the object side, it can be designed such that the effective diameter of the lens gradually increases from the position of the aperture to the sensor, and the number of lenses can be reduced. Also, since the conditions of L1R1 > L1R2 and |L3R1| > L3R2 are satisfied, the effective diameter of the second lens can be designed to be the minimum, and the TTL can be reduced. If the condition is |L3R1| < L3R2, there is a problem that the TTL increases. The radii of curvature of the third and fourth lenses are set larger than those of the other lenses but set to be 20 mm or less, so that the influence on the optical characteristics covering the incident light can be reduced.

[0116] [Equation 8] 0.5 < BFL / Max_Sag52 to Sensor < 1.5 The BFL is the optical axis distance from the center of the sensor side of the last lens, i.e., the 5th lens, to the surface of the image sensor. Max_Sag52 to Sensor may be the maximum Sag value of the sensor side of the 5th lens 105, i.e., the distance in the optical axis direction from the low point to the image sensor 300. When the optical system satisfies Equation 8, the TTL can be reduced and the conditions for manufacturing the camera module can be set. Also, Max_Sag52 to Sensor can set the space where the optical filter 500 and the cover glass 400 located between the image sensor 300 and the 5th lens 105 can be arranged. When the range of Equation 8 is smaller than the lower limit value, the constraints on the space for arranging circuit structures such as the optical filter or the image sensor increase, and the process of assembling the structures into the optical system becomes difficult. When the range of Equation 8 is larger than the upper limit value, the process of assembling circuit structures such as the filter and the image sensor into the optical system is easy, but the TTL becomes long and it is difficult to miniaturize the optical system. When there is no point on the sensor side of the last lens that protrudes in the direction of the image sensor more than the center of the sensor side between the optical axis and the edge, Max_Sag52 is 0, and the value of Equation 8 is the same as the BFL (Back focal length).

[0117] [Equation 9] 0.5 < CT1 / CT5 < 1.5 When Equation 9 is satisfied, the aberration characteristics can be improved and the influence on the reduction of the optical system can be set. Equation 9 preferably satisfies 0.85 < CT1 / CT5 < 1.25, or CTl and CT5 may be the same. Equation 9 can set the center thicknesses of the first lens on the object side of the optical system and the 5th lens having a spherical surface, and limit the difference between these center thicknesses. Thereby, the chromatic aberration of the optical system can be improved, it has good optical performance at the set angle of view, and the TTL (total track length) can be controlled.

[0118] [Equation 9-1] 0 < CT1 / CA11 < 0.5 The central thickness CT1 of the first lens 101 and the effective diameter CA11 of the object side surface S1 of the first lens 101 can be set by Equation 9-1. When this is satisfied, it is possible to prevent a decrease in the strength and optical characteristics of the glass material lens. If it is lower than the range of Equation 9-1, the lens may be damaged or injection molding may be difficult. If it is larger than the range, the TTL increases and the weight of the optical system becomes heavy. Preferably, 0 < CT1 / CA11 < 0.3 can be satisfied.

[0119] [Equation 10] 1 < CT4 / (CT1 + CT2 + CT5) < 2 CT1, CT2, CT4, and CT5 represent the central thicknesses of the first, second, third, and fifth lenses. When the optical system satisfies Equation 10, the ratio of the central thickness of the thickest fourth lens to the central thickness of the thin lenses can be set, the aberration characteristics can be improved, and the influence on the reduction of the optical system can be set. Equation 10 can preferably satisfy 1 < CT4 / (CT1 + CT2 + CT) < 1.5.

[0120] [Equation 11] 1 < CT3 / (CT1 + CT5) < 2.5 In Equation 11, the central thickness of the third lens 103 can be set to be larger than the sum of the central thicknesses of the first and fifth lenses. The third lens with convex surfaces on both sides can guide light to the entire area of the fourth lens.

[0121] [Equation 12] 4 < CT34 / CT5 < 10 CT34 is the sum of the central thicknesses of the third and fourth lenses. When Equation 12 is satisfied, by arranging the sum of the central thicknesses of the third and fourth lenses to exceed four times the central thickness of the fifth lens 105, the sensitivity of the light traveling through the third and fourth lenses 103 and 104 can be reduced, and the assembly property of the third and fourth lenses 103 and 104 can be improved. Preferably, it can satisfy 6 < CT34 / CT5 < 8.

[0122] [Equation 13] 1 < CA11 / CA21 < 2 CA11 means the effective diameter of the first surface S1 of the first lens 101, and CA21 means the effective diameter of the third surface S3 of the second lens 102. When Formula 13 is satisfied, the optical system 1000 can control the incident light, and can set elements that affect aberration. Preferably, 1 < CA11 / CA31 < 1.6 can be satisfied. Since the first and second lenses satisfy Formula 13, the difference in the effective diameters of the first and second lenses is small, so the influence on assembly can be reduced, and the optical influence due to temperature change can be reduced.

[0123] [Formula 14] 1 < CA52 / CA21 < 3 CA52 means the effective diameter of the tenth surface S10 of the fifth lens 105, and CA21 means the effective diameter of the third surface S3 of the second lens 102. When Formula 14 is satisfied, the optical system 1000 can control the incident light path, and can set elements for performance changes due to CRA and temperature. Preferably, Formula 14 can satisfy 1.8 < CA52 / CA21 < 2.5. Formula 14 can set the effective diameters of the object side surface of the first lens and the sensor side surface of the last lens in the second lens group.

[0124] [Formula 15] 0 < CA12 / CA21 < 2 CA12 means the effective diameter of the second surface S2 of the first lens 101, and CA21 means the effective diameter of the third surface S3 of the second lens 102. When the optical system 1000 according to the embodiment satisfies Formula 15, the light traveling from the first lens group LG1 to the second lens group LG2 can be controlled, and elements that affect the reduction of lens sensitivity can be set. Formula 15 can preferably satisfy 0.8 < CA12 / CA21 < 1.5. Since the first and second lenses satisfy Formula 15, the size for the assembly of the spherical lens and the aspherical lens can be set.

[0125] [Formula 16] 0 < ΣASL_CT / ΣSSL_CT <​ΣASL_CT is the sum of the center thicknesses of the aspherical lenses, for example, the center thickness of the first lens. ΣSSL_CT is the sum of the center thicknesses of the spherical lenses, for example, the sum of the center thicknesses of the second to fifth lenses. When formula 16 is satisfied, the overall TTL can be controlled by setting the relationship between the thickness of the aspherical lens and the thickness of the spherical lens relative to TTL. In a preferred embodiment, formula 16 satisfies 0<ΣASL_CT / ΣSSL_CT<0.2.

[0126] [Formula 17] 0<ΣASL_CT / TD<0.2 TD is the optical axial distance from the center of the object-side surface of the first lens to the center of the sensor-side surface of the fifth and final lens. Equation 17 defines the relationship between the sum of the center thicknesses of the aspherical lenses in the optical system and the maximum optical axial distance between the lenses. Equation 17 preferably satisfies 0<ΣASL_CT / TD<0.1.

[0127] [Formula 18] 0.2<ΣSSL_CT / TD<0.7 Equation 18 defines the relationship between the sum of the center thicknesses of the spherical lenses in the optical system and the maximum optical axis distance between the lenses. Preferably, 0.4<(including =, less than or equal to)ΣSSL_CT / TD<0.6 can be satisfied.

[0128] [Formula 19] 0.1<ΣSSL_CT / TTL<0.6 Formula 19 can set the relationship between the sum of the center thicknesses of the spherical lenses and the total optical length TTL. Formula 19 preferably satisfies 0.3<(including =, less than or equal to)ΣSSL_CT / TTL<(including =, less than or equal to) 0.5.

[0129] [Formula 20]1 <SSL_CA_Aver / ASL_CA_Aver<2 SSL_CA_Aver represents the average effective diameter of a glass lens with a spherical surface, and ASL_CA_Aver represents the average effective diameter of a glass mold lens with an aspherical surface. By setting the effective diameters of the spherical lens and the aspherical lens in Equation 20, the path of the incident light can be effectively guided. Equation 20 can preferably satisfy 1 < SSL_CA_Aver / ASL_CA_Aver < 1.5. The embodiment can reduce the number of lenses and prevent deterioration of optical characteristics by mixing a spherical lens and an aspherical lens in the optical system.

[0130] [Equation 21] 0 < SSL_Nd_Aver / ASL_Nd_Aver < 1.60 SSL_Nd_Aver is the average refractive index of the spherical lens, and ASL_Nd_Aver is the average refractive index of the aspherical lens. Preferably, the refractive index of the spherical lens and the refractive index of the aspherical lens can be set to satisfy the condition of 1 < SSL_Nd_Aver / ASL_Nd_Aver < 1.3.

[0131] [Equation 21-1] ΣASL_Nd < ΣSSL_Nd ΣASL_Nd is the sum of the refractive indices of the aspherical lenses, and ΣSSL_Nd is the sum of the refractive indices of the spherical lenses. The optical system can set the sum of the refractive indices of the spherical lenses to be higher than the sum of the refractive indices of the aspherical lenses on the object side to adjust the resolution and chromatic dispersion.

[0132] [Equation 22] (CG1 + CG2) < CT3 CG1 is the center-to-center distance between the first and second lenses, and CG2 is the center-to-center distance between the second and third lenses. By increasing the center thickness of the third lens and reducing the center-to-center distance between the first to third lenses in Equation 22, the TTL can be adjusted. Here, the conditions of (CT1 × 2) < CG2 or (CT2 × 2) < CG2 can be satisfied.

[0133] [Equation 23] 0.20 < LD12 / LD35 < 0.50 LD12 is the optical axial distance between two lenses adjacent to the object, for example, the optical axial distance from the center of the object side of the first lens 101 to the center of the sensor side of the second lens 102. LD35 is the optical axial distance between three lenses adjacent to the sensor, for example, the optical axial distance from the center of the object side of the third lens 103 to the center of the sensor side of the fifth lens 105. In Equation 23, the optical axial distance between the lenses 101 and 102 disposed on the object is small, and the optical axial distance between the lenses 103, 104, and 105 disposed on the sensor side is large, thereby correcting distortion and chromatic aberration caused by the first and second lenses 101 and 102. Preferably, the optical axial distance from the object side of the first lens 101 to the sensor side of the second lens 102 is set to be 26% or more and 36% or less of the optical axial distance from the object side of the third lens 103 to the sensor side of the fifth lens 105. Satisfying Equation 23 reduces aberrations and distortions that may occur in an optical system with a small TTL. That is, the following can be satisfied: 0.26<(=included, less than or equal to) LD12 / LD35<(=included, less than or equal to) 0.36.

[0134] [Formula 24]0 <LD12 / TTL<0.3 The optical axis distance between the two lenses on the object side relative to the overall length TTL can be set using Equation 24, and the effective diameter, radius of curvature, refractive index, Abbe number, etc. of the glass lens can be set. Preferably, the following relationship can be satisfied: 0.11<(= inclusive, less than or equal to) LD12 / TTL<(= inclusive, less than or equal to) 0.23.

[0135] [Formula 25]0 <CT4 / TTL<0.3 By setting the center thickness of the fourth lens within the above range based on TTL in Equation 25, light incident through the first to third lenses can be refracted to the entire area of ​​the fifth lens, thereby improving chromatic aberration in the optical system.

[0136] [Formula 25-1] 0.4 <CT4 / ImgH<0.9 By setting the center thickness of the third lens ImgH in the above range in accordance with Equation 25-1, it is possible to reduce the change in optical characteristics due to temperature changes.

[0137] [Formula 26] 0<|L2R1 / L5R2|<1 L2R1 is the radius of curvature of the third surface of the second lens, and L5R2 is the radius of curvature of the tenth surface of the fifth lens. The powers of the second and fifth lenses can be controlled by setting the radii of curvature of the object-side surface of the second lens and the sensor-side surface of the fifth lens using Equation 28. This allows for good optical performance in the central and peripheral areas of the angle of view. Preferably, Equation 26 satisfies 0<|L2R1 / L5R2|<0.5.

[0138] [Formula 27] 3<|L5R1 / CT5|<10 L5R1 refers to the radius of curvature of the object-side surface of the fifth lens. When formula 27 is satisfied, the power of the fourth lens can be controlled to control incident light with the aspherical lens, preventing deterioration in the ease of assembling the aspherical lens. Preferably, 6<(including =, less than or equal to)|L5R1 / CT5|<9 can be satisfied.

[0139] [Formula 28] 1.2<|L3R1 / L3R2|<5 L3R1 is the radius of curvature of the object side surface of the third lens, and L3R2 is the radius of curvature of the sensor side surface of the third lens. When Equation 28 is satisfied, the light sensitivity can be reduced by adjusting the radius of curvature of the lens located at the center of the optical system. Preferably, 2<(including =, less than or equal to)|L3R1 / L3R2|<2.5 can be satisfied.

[0140] [Formula 29] 0.5<|L4R1 / L4R2|<1.5 L4R1 is the radius of curvature of the object side surface of the fourth lens, and L4R2 is the radius of curvature of the sensor side surface of the fourth lens. When Equation 29 is satisfied, the light sensitivity can be reduced by adjusting the radius of curvature of the lens located at the center of the optical system. Preferably, |L4R1 / L4R2|=1 can be satisfied.

[0141] [Formula 30] |S7SagD1|-|S8SagD1|<0.2mm S7 Sag D1 is the Sag value at the 7th surface S7 of the fourth lens 104 at a first distance D1 from the optical axis, and S8 Sag D1 is the Sag value at the 8th surface S8 of the fourth lens 104 at a first distance D1 from the optical axis. That is, the fourth lens 104 can have a difference of less than 0.2 mm at a point where the Sag values of the 7th surface and the 8th surface S8 are separated by a first distance D1 with respect to the optical axis. The first distance D1 is at a point of 1 / 2 of the average effective radius of the fourth lens 104 with respect to the optical axis. Here, S7 Sag D1 > 0 and S8 Sag D1 < 0.

[0142] [Equation 31] 0.5 < SD / TD < 1 SD is the optical axis distance from the aperture to the center of the sensor side surface of the last lens, and TD is the optical axis distance from the center of the object side surface of the first lens to the center of the sensor side surface of the last lens. That is, the relationship between the position of the aperture and the maximum distance between the entire lenses can be set. Preferably, it can satisfy 0.8 < SD / TD < 0.95.

[0143] [Equation 32] 0.5 < CT_Max / CG_Max < 1.5 In Equation 32, the maximum center thickness CT_Max of the lenses and the maximum center distance CG_Max between adjacent lenses can be set. When Equation 32 is satisfied, the optical system can have good optical performance at the set angle of view and focal length, and the TTL can be reduced. Preferably, the embodiment can satisfy 0.8 < CT_Max / CG_Max < 1.2.

[0144] [Equation 33] 1 < ΣCT / ΣCG < 5 In Equation 33, ΣCT is the sum of the center thicknesses of the lenses, and ΣCG is the sum of the center distances between adjacent lenses. When Equation 3 is satisfied, the optical system can have good optical performance at the set angle of view and focal length, and the TTL can be reduced. Preferably, the embodiment can satisfy 1 < ΣCT / ΣCG < 1.5.

[0145] [Equation 34] 6 < ΣNd < 11 ΣNd means the sum of the refractive indices at the d - lines of each of the plurality of lenses. When Equation 34 is satisfied, TTL can be controlled in the optical system 1000 in which an aspherical lens and a spherical lens are mixed, and improved resolution can be achieved. Also, a glass lens having a relatively high refractive index and a thick thickness can be arranged at the center to set TTL and the refractive index. Equation 34 can preferably satisfy 6 <= (including <=, less than or equal to) ΣNd <= (including <=, less than or equal to) 10.

[0146] [Equation 35] 10 < ΣAbbe / ΣNd < 50 ΣAbbe means the sum of the Abbe numbers of each of the plurality of lenses. When Equation 35 is satisfied, the optical system 1000 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 28 < ΣAbbe / ΣNd < 40 can be satisfied.

[0147] [Equation 36] 0.5 < CA11 / CA_Min < 2.5 CA11 is the effective diameter of the object side surface 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 36 is satisfied, the optical system can control the incident light, maintain the optical performance, and provide a more slender module. Equation 36 can preferably satisfy 1 < CA11 / CA_Min < 2.

[0148] [Equation 37] 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 37 is satisfied, the optical system can maintain the optical performance and set the size for a slim and compact structure. Equation 37 can preferably satisfy 2 < CA_Max / CA_Min < 2.5.

[0149] [Equation 38] 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 38 is satisfied, the optical system can maintain optical performance and set the size for a slim and compact structure. Equation 38 can preferably satisfy 1 < CA_Max / CA_Aver < 1.5.

[0150] [Equation 39] 20 < CA_Max × nL < 32 nL is the number of lenses in the optical system and can be, for example, 5. When Equation 39 is satisfied, the optical system can set the maximum effective diameter according to the total number of lenses. Equation 39 can preferably satisfy 25 < CA_Max × nL < 30.

[0151] [Equation 40] 0.5 < CA_Max / (2 × ImgH) < 2 Equation 40 can be set with the maximum effective diameter CA_Max of the lens surface and the diagonal length of the image sensor. When this is satisfied, the optical system can maintain good optical performance and set the size for a slim and compact structure. Preferably, it can satisfy 0.6 < CA_Max / (2 × ImgH) < 1.

[0152] [Equation 41] 0.5 < TD / CA_Max < 4 When Equation 41 is satisfied, the total 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 41 can preferably satisfy 1.5 < TD / CA_Max < 2.2.

[0153] [Equation 42] 0 < TD / CT_Max < 0.7 With Equation 42, the maximum center thickness and the maximum optical axis distance of the lens can be set, and good optical performance can be improved. Preferably, it can satisfy 0 < (= including, less than or equal to) TD / CT_Max < (= including, less than or equal to) 0.3.

[0154] [Equation 43] 0 < F / CA51 < 1.5 F represents the effective focal length EFL of the optical system, which can be less than 15 mm or 10 mm or less, for example, in the range of 1 mm to 10 mm. By setting the relationship between the effective focal length and the effective diameter of the object side surface of the last spherical lens in Equation 43, the reduction of the optical system, for example, the influence on TTL can be adjusted. Equation 43 can preferably satisfy 0.8 < F / CA51 < 1.2.

[0155] [Equation 44] 0 < F / L1R1 < 2 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 incident light and the influence on TTL can be adjusted. Equation 44 can preferably satisfy 1 < F / L1R1 < 1.5.

[0156] [Equation 45] 0.5 < Max(CT / ET) < 1.5 Max(CT / ET) indicates the maximum value of the ratio of the center thickness to the edge thickness of each lens. When Equation 45 is satisfied, the optical system can adjust the influence on the effective focal length. Equation 45 can preferably satisfy 0.8 < Max(CT / ET) < 1.2.

[0157] Looking at the ratio of the center thickness to the edge thickness of the spherical lens and the aspherical lens within the lens unit, the condition Max_SSL(CT / ET) > Max_ASL(CT / ET) can be satisfied. Max_SSL(CT / ET) indicates the maximum of the ratio of the center thickness to the edge thickness among the spherical lenses, and Max_ASL(CT / ET) can indicate the maximum of the ratio of the center thickness to the edge thickness of the aspherical lens.

[0158] [Equation 46] 0 < EPD / L1R1 < 1 EPD means the size (mm) of the entrance pupil of the optical system 1000. When the optical system 1000 according to the embodiment satisfies Equation 46, the optical system 1000 can control the incident light. Equation 46 can preferably satisfy 0.5 < EPD / LinR1 < 0.8.

[0159] [Formula 47] 1<|F1 / F3|<4 F1 is the focal length of the first lens, and F3 is the focal length of the third lens. When Formula 47 is satisfied, the power of the first and third lenses can be controlled to improve the resolving power and affect the TTL and effective focal length F. Preferably, the following relationship can be satisfied: 2<(including =, less than or equal to) F1 / F3<(including =, less than or equal to) 2.7.

[0160] [Formula 47-1] |F1|>F4 [Formula 47-2] |F1|>F3 [Formula 47-3] |F1|<|F2| [Formula 47-4]F <F4<|F1| [Formula 47-5]F <F4<|F5| In Formulas 47-1 to 47-5, F1 is the focal length of the first lens, F2 is the focal length of the second lens, F3 is the focal length of the third lens, F4 is the focal length of the fourth lens, and F5 is the focal length of the fifth lens. By controlling the power of each lens, light can be guided through the spherical lens by the aspherical lens. The aperture ST is disposed on the sensor side of the first lenses 101 and 112. The focal length of the lens disposed closest to the aperture ST and closer to the sensor side than the aperture ST is less than zero. In this embodiment of the present invention, F2, which is the focal length of the second lens 102, must be designed to be less than zero. In this case, since the second lens 102 has a meniscus shape that bulges toward the sensor, the radius of curvature of the object side surface of the third lens 103 can be increased. Since the third lens 103 has positive power, the effective diameters of the third and fourth lenses can be increased.

[0161] The composite focal length F25 of the second to fifth lenses can have positive power. That is, the composite focal length F25 of the lens located closer to the sensor than the aperture ST, i.e., the lens located closer to the sensor than the aperture ST, is designed to be greater than 0. In this case, the TTL can be reduced when the horizontal angle of view FOV_H is between 45 and 60 degrees, making it possible to downsize the optical system.

[0162] [Equation 48] |Po5| < Po4 < Po3 Po3 is the power value of the third lens, Po4 is the power value of the fourth lens, and Po5 is the power value of the fifth lens. Since the powers of the third and fourth lenses are positive values and the power of the fifth lens has a negative value, the fifth lens can compensate for the aberration generated by the third and fourth lenses.

[0163] [Equation 49] 15 < Vd2 - Vd3 < 60 In Equation 49, Vd2 is the Abbe number of the second lens and Vd3 is the Abbe number of the third lens. When Equation 49 is satisfied, the difference in the Abbe numbers of two adjacent lenses can be maintained at a certain value or more, and chromatic aberration can be improved. Equation 49 can preferably satisfy 20 < Vd2 - Vd3 < 40.

[0164] [Equation 50] 0 < |F25 / F12| < 2 By setting the relationship between the combined focal length F12 of the first and second lenses and the combined focal length F35 of the third to fifth lenses in Equation 50, the power of the first and second lens groups can be controlled to improve the resolution, and the optical system can be provided in a slim and compact size. Equation 50 can preferably satisfy 0 < |F25 / F12| < 1.

[0165] [Equation 51] 0 < |F25 / F| < 2 By setting the relationship between the overall focal length F and the combined focal length F25 of the second to fifth lenses in Equation 51, the power of each lens can be controlled to improve the resolution. Equation 51 can preferably satisfy 0.5 < |F25 / F| < 1.

[0166] [Equation 52] 0 < |F35 / F12| < 2 By setting the relationship between the combined focal length F12 of the first and second lenses and the combined focal length F35 of the third to fifth lenses in Equation 52, the combined focal length of the two lenses with a small effective diameter and the combined focal length of the three lenses with a large effective diameter are set within the above range, and the combined power of each lens can be controlled to improve the resolution. Equation 52 can preferably satisfy 0 < |F35 / F12| < 1, where F35 > 0 and F12 < 0.

[0167] [Equation 53] |F_SSL_Aver| < |F_ASL_Aver| In Equation 53, F_SSL_Aver is the average of the focal lengths of the spherical lenses, and F_ASL_Aver is the average of the focal lengths of the aspherical lenses. When Equation 53 is satisfied, chromatic aberration and distortion can be improved by the combination of the spherical lens and the aspherical lens.

[0168] [Equation 54] 0 < nASL / nL < 0.5 nASL is the number of aspherical lenses, and nL indicates the total number of lenses.. By arranging the number of aspherical lenses to be less than 0.5 times the total number of lenses in Equation 54, the thickness of the optical system can be reduced, and more diverse powers can be provided through the aspherical surface. Also, Equation 54-1 can satisfy 0.5 < nSSL / nL < 1, where nSSL is the number of glass lenses.

[0169] [Equation 55] 0.70 < DL3S / TTL < 0.90 DL3S is the optical axis distance from the center of the object side surface of the third lens to the image sensor. By setting the center thickness of the third and fourth lenses of the optical system to be thick and increasing the center distance between the third to fifth lenses, the ratio of DL3S to TTL length is set within the above range, and the optical system can be designed to guide the incident light without aberration and distortion. Preferably, it can satisfy 0.75 <= DL3S / TTL <= 0.85. That is, DL3S, the optical axis distance from the center of the object side surface of the third lens to the image sensor, may be provided within the range of 75% to 85% of TTL.

[0170] [Formula 56] 5mm <TTL<20mm TTL (Total track length) means the distance on the optical axis OA from the center of the first surface S1 of the first lens 101 to the surface of the image sensor 300. In Equation 56, TTL can be set to 15 mm or less to provide an optical system for a vehicle. Preferably, 10 mm < (including =, less than or equal to) TTL < (including =, less than or equal to) 15 mm can be satisfied.

[0171] [Formula 57] 2mm <ImgH Formula 57 can set 1 / 2 of the diagonal length of image sensor 300, making it possible to provide an optical system having the size of a sensor for a vehicle. Formula 57 preferably satisfies 2.8 mm<(including =, less than or equal to) ImgH<5 mm.

[0172] [Formula 58] 1mm <BFL<3mm In Equation 58, the back focal length (BFL) is set to be greater than 1 mm and less than 3 mm to ensure installation space for the optical filter 500 and the cover glass 400, and the distance between the image sensor 300 and the final lens can improve assembly of the components and improve connection reliability. Equation 58 preferably satisfies 1.5 mm < (including, less than or equal to) BFL < (including, less than or equal to) 2.8 mm. If the BFL is less than the range of Equation 58, some light traveling to the image sensor may not be transmitted to the image sensor, resulting in reduced resolution. If the BFL exceeds the range of Equation 58, stray light may enter, degrading the aberration characteristics of the optical system.

[0173] [Formula 59]1 <BFL / CG2<3 In Equation 59, the back focal length (BFL) and the center-to-center distance CG4 between the fourth and fifth lenses are set, and the bonding reliability of components can be improved by the installation space of the optical filter 500 and the cover glass 400 and the distance between the glass lens adjacent to the sensor. Equation 59 can satisfy 1.2 ≤ BFL / CG4 ≤ 1.5 (including "="). The center-to-center distance CG4 between the fourth and fifth lenses may be the largest within the lens unit.

[0174] [Equation 60] 0 < CT3 / BFL < 1 In Equation 60, the back focal length (BFL) is set to be greater than the center thickness of the first lens, so that the installation space of the optical filter 500 and the cover glass 400 can be ensured, the assembly property of components can be improved by the distance between the image sensor 300 and the last lens, and the bonding reliability can be improved. If the BFL does not satisfy Equation 60, part of the emitted light may not be transmitted to the effective area of the image sensor, thereby reducing the resolution. Preferably, 0.5 < CT1 / BFL ≤ 0.9 can be satisfied.

[0175] [Equation 61] F < 15 mm Equation 61 can set the overall effective focal length F to suit the vehicle optical system. Equation 61 can satisfy the range of 1 mm ≤ F ≤ 10 mm or 3 mm ≤ F ≤ 8 mm.

[0176] [Equation 62] 45° < FOV < 75° In Equation 62, FOV (Field of view) means the angular field (Degree) in the diagonal direction of the optical system 1000, and a vehicle optical system with an angular field less than 75° can be provided. Preferably, 55° ≤ FOV ≤ 74° can be satisfied.

[0177] [Equation 63] 1 < TTL / CA_Max < 3 CA_Max means the largest effective diameter (mm) among the object side and the sensor side of the plurality of lenses. Equation 63 can set the relationship between the overall optical axis length and the maximum effective diameter of the optical system, and provide a slim vehicle optical system. Equation 63 can preferably satisfy 2 < TTL / CA_Max <= (including <=, less than or equal to) 2.5.

[0178] [Equation 64] 3 < TTL / ImgH < 5 Equation 64 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 300. When the optical system 1000 according to the embodiment satisfies Equation 64, the optical system 1000 can have a large ImgH of the TTL comparison size for the application of the vehicle image sensor 300, and can provide a more improved image quality. Equation 64 can preferably satisfy 3.5 <= (including <=, less than or equal to) TTL / ImgH <= (including <=, less than or equal to) 4.5.

[0179] [Equation 65] 0.1 < BFL / ImgH < 1.5 Equation 65 can set the optical axis interval between the image sensor 300 and the last lens and the diagonal length in the optical axis direction of the image sensor 300. When the optical system 1000 according to the embodiment satisfies Equation 65, the optical system 1000 can ensure the BFL (Back focal length) for applying the size of the vehicle image sensor 300, can set the interval between the last lens and the image sensor 300, and can have good optical characteristics at the center and periphery of the viewing angle FOV. Equation 65 is preferably 0.5 < BFL / ImgH < 1, and can satisfy the condition of BFL < ImgH.

[0180] [Equation 66] 1 < TTL / BFL < 10 Equation 66 can set the overall optical axis length TTL of the optical system and the optical axis interval BFL between the image sensor 300 and the last lens. When the optical system 1000 according to the embodiment satisfies Equation 66, the optical system 1000 can secure the BFL. Equation 66 can preferably satisfy 3 <= (including <=, less than or equal to) TTL / BFL < 5.

[0181] [Equation 67] 1 < TTL / F < 3 Equation 67 can set the overall focal length F and the overall optical axis length TTL of the optical system 1000. Thereby, an optical system for a driver assistance system or a driver monitoring can be provided. Equation 67 can preferably satisfy 2 <= (including <=, less than or equal to) TTL / F < 2.8. When the optical system 100 according to the embodiment satisfies Equation 67, the optical system 1000 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 67, it is necessary to increase the power of the lens, and it becomes difficult to correct spherical aberration or distortion aberration. If it exceeds the upper limit value of Equation 67, problems such as the effective diameter and TTL of the lens becoming long and the imaging lens system becoming large may occur.

[0182] [Equation 68] 1 < F / BFL < 10 Equation 68 can set the overall effective focal length F of the optical system 1000 and the optical axis interval BFL between the image sensor 300 and the last lens. When the optical system 1000 according to the embodiment satisfies Equation 68, the optical system 1000 can have a set angle of view, have an appropriate focal length, and provide an optical system for a vehicle. Also, the optical system 1000 can minimize the interval between the last lens and the image sensor 300 and can have good optical characteristics at the peripheral part of the angle of view FOV. Equation 68 can preferably satisfy 1.5 < F / BFL < 2.5.

[0183] [Equation 69] 1 < F / ImgH < 5 Equation 69 can set the overall effective focal length F of the optical system 1000 and the diagonal length ImgH on the optical axis of the image sensor 300. Such an optical system 1000 can have aberration characteristics improved with the size of the vehicle image sensor 300. Equation 69 can preferably satisfy 1.2 < F / ImgH < 2.

[0184] [Equation 70] 1 < F / EPD < 5 Equation 70 can set the overall effective focal length F of the optical system 1000 and the size of the entrance pupil. Thereby, the overall brightness of the optical system can be controlled. Equation 70 can preferably be set to 1 < F / EPD < 3.

[0185] [Equation 71] 0 < BFL / TD < 0.5 Equation 71 can set the relationship between the optical axis distance TD of the lens of the optical system 1000 and the back focal length BFL. Thereby, the resolution of the optical system can be maintained and the overall size can be controlled. Equation 71 can preferably satisfy 0.2 <= (including =, less than or equal to) BFL / TD < 0.3. When the conditional value of BFL / TD exceeds 0.5, since TD compared to BFL is designed to be large, the overall size of the optical system becomes large, making it difficult to miniaturize the optical system. The distance between the fifth lens and the image sensor becomes long, and thereby unnecessary light amount increases through the space between the fifth lens and the image sensor, resulting in problems such as a decrease in resolution due to a decrease in aberration characteristics.

[0186] [Equation 72] 0 < EPD / ImgH / FOV < 0.2 Equation 72 can set the relationship between the size EPD of the entrance pupil, half of the diagonal length ImgH of the image sensor, and the angular field in the diagonal direction. Thereby, the overall size and brightness of the optical system can be controlled. Equation 72 can preferably satisfy 0 < EPD / ImgH / FOV < 0.1.

[0187] [Equation 73] 20 < FOV / F# < 40 Equation 73 can set the relationship between the angular field of view and the F-number of the optical system. Equation 73 can preferably satisfy 30 < FOV / F# < 36. Here, F# can be provided to be 2.3 or less to provide a bright image.

[0188] [Equation 74] 15 < ΣSSL_CT × nSSL < 22 Equation 74 can set the center thickness and the number of spherical lenses as the value obtained by multiplying the sum ΣSSL_CT of the center thicknesses of the spherical lenses and the number nSSL of the spherical lenses. Preferably, Equation 74 can satisfy 16 ≤ (including =, less than or equal to) ΣGL_SST × nSSL ≤ (including =, less than or equal to) 20.

[0189] [Equation 75] 0 < ΣASL_CT × nASL < 1 Equation 75 can set the center thickness and the number of aspherical lenses as the value obtained by multiplying the sum ΣASL_CT of the center thicknesses of the aspherical lenses and the number nASL of the aspherical lenses. Preferably, Equation 75 can satisfy 0.4 ≤ (including =, less than or equal to) ΣASL_CT × nASL ≤ (including =, less than or equal to) 0.6.

[0190] [Equation 76] 40 < TTL × nSSL < 60 Equation 76 can set TTL and the number of spherical lenses, and the chromatic dispersion and the refraction angle can be adjusted by the spherical lenses in an optical system having a TTL of 15 mm or less.

[0191] [Equation 77] 8 < ImgH × nSSL < 16 Equation 77 can set ImgH and the number of spherical lenses, and the chromatic dispersion and the refraction angle can be adjusted by the spherical lenses in an optical system having an ImgH of less than 5 mm.

[0192] [Equation 78] |Max_Sag42| < |Max_Sag51| Max_Sag42 is the maximum distance in the optical axis direction from a line perpendicular to the optical axis at the sensor side of the fourth lens to the sensor side of the fourth lens, and Max_Sag51 is the maximum distance in the optical axis direction from a line perpendicular to the optical axis at the object side of the fifth lens to the object side of the fifth lens. When Equation 78 is satisfied, the radius of curvature of the lens surface of the spherical lens can be adjusted to guide light to the entire area of ​​the image sensor, and the effective diameters of the fourth and fifth lenses can be adjusted.

[0193] [Formula 79] |Max_Sag52| < |Max_Sag51| Max_Sag52 is the maximum distance in the optical axis direction from a line perpendicular to the optical axis on the sensor side of the fifth lens to the sensor side of the fifth lens. When Equation 79 is satisfied, the effective diameter of the fifth lens can be adjusted by adjusting the radii of curvature of the object side and sensor side of the fifth lens. Here, Max_Sag52 and Max_Sag51<0.

[0194] [Formula 80] TIFF2025529551000003.tif14121

[0195] In Equation 80, Z may represent Sag, which is the distance from an arbitrary position on the aspherical surface to the apex of the aspherical surface in the optical axis direction. Y may represent the distance from an arbitrary position on the aspherical surface to the optical axis in a direction perpendicular 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.

[0196] The optical system 1000 according to the embodiment may satisfy at least one or two or more of Equations 1 to 40. At least one or two or more of Equations 1 to 40 may satisfy at least one or two or more of Equations 41 to 79. In this case, the optical system 1000 may have improved optical characteristics. Specifically, when the optical system 1000 satisfies at least one of Equations 1 to 40 and / or at least one of Equations 41 to 79, the optical system 1000 may have improved resolving power and improved aberration and distortion characteristics. In addition, the optical system 1000 may ensure a back focal length (BFL) for application to the vehicle image sensor 300, compensate for deterioration of optical characteristics due to temperature changes, minimize the distance between the last lens and the image sensor 300, and have good optical performance in the center and peripheral parts of the field of view (FOV).

[0197] Table 2 shows the TTL (Total track length) (mm), BFL (Back focal length), effective focal length F (mm), ImgH (mm), effective diameter CA (mm), TTL (mm), TD (mm) which is the optical axial distance from the first surface S1 to the tenth surface S10, the focal lengths F1, F2, F3, F4, and F5 (mm) of the first to fifth lenses, the sum of the refractive indices, the sum of the Abbe numbers, the sum of the center thicknesses of the lenses (mm), the sum of the spacing between adjacent lenses, the diagonal angle of view FOV (Degrees), the edge thickness ET, the focal lengths of the first and second lens groups, the composite focal length of the second to fourth lenses, the F-number, and the like for the optical system 1000 of the embodiment. [Table 2]

[0198] Table 3 shows the result values ​​for the above-mentioned formulas 1 to 40 in the optical system 1000 of the example. Referring to Table 2, it can be seen that the optical system 1000 satisfies at least one, two or more, or three or more of formulas 1 to 40. In particular, it can be seen that the optical system 1000 according to the example satisfies all of formulas 1 to 40. As a result, the optical system 1000 can have good optical performance in the center and periphery of the field of view FOV, and can have excellent optical characteristics. [Table 3] TIFF2025529551000006.tif199159

[0199] Table 4 shows the results of the above-mentioned formulas 41 to 79 in the optical system 1000 of the example. Referring to Table 3, it can be seen that the optical system 1000 satisfies at least one, two or more, or three or more of formulas 41 to 79. In particular, it can be seen that the optical system 1000 according to the example satisfies all of formulas 41 to 79. As a result, the optical system 1000 can have good optical performance in the center and periphery of the field of view FOV, and can have excellent optical characteristics. [Table 4] TIFF2025529551000008.tif134161

[0200] FIG. 13 is an example of a plan view of a vehicle to which a camera module or optical system according to an embodiment of the invention is applied. Referring to FIG. 13, the vehicle camera system according to the embodiment of the invention includes an image generator 11, a first information generator 12, second information generators 21, 22, 23, 24, 25, and 26, and a controller 14. The image generator 11 may include at least one camera module 31 disposed in the host vehicle and may capture images of the area in front of the host vehicle and / or the driver to generate images of the area in front of the host vehicle and images of the interior of the vehicle. The image generator 11 may use the camera module 31 to capture images of the area around the host vehicle in one or more directions as well as the area in front of the host vehicle to generate images of the area around the host vehicle. Here, the images of the area in front of the host vehicle and the surrounding area may be digital images and may include color images, monochrome images, infrared images, etc. The images of the area in front of the host vehicle and the surrounding area may include still images and video images. The image generator 11 provides the driver image, the image of the area in front of the host vehicle, and the surrounding area to the controller 14. The first information generator 12 may include at least one radar and / or camera disposed in the host vehicle and generates the first sensing information by sensing the area ahead of the host vehicle. Specifically, the first information generator 12 is disposed in the host vehicle and senses the position and speed of a vehicle ahead of the host vehicle, the presence and position of a pedestrian, etc., to generate the first sensing information.

[0201] The first detection information generated by the first information generator 12 can be used to control the host vehicle to maintain a constant distance from a vehicle in front, thereby improving the stability of vehicle operation in specific pre-set cases, such as when the driver changes the roadway on which the host vehicle is traveling or when reversing into parking. The first information generator 12 provides the first detection information to the controller 14. The second information generators 21, 22, 23, 24, 25, and 26 generate second detection information by detecting each side of the host vehicle based on the forward image generated by the image generator 11 and the first detection information generated by the first information generator 12. Specifically, the second information generators 21, 22, 23, 24, 25, and 26 may include at least one radar and / or camera disposed on the host vehicle and may detect the position and speed of vehicles positioned on the sides of the host vehicle and capture images. Here, the second information generators 21, 22, 23, 24, 25, and 26 may be arranged at both front corners, side mirrors, and the rear center and both rear corners of the vehicle, respectively.

[0202] At least one information generator in such a vehicle camera system may include the optical system and a camera module having the same described in the embodiments disclosed above. The optical system may provide or process information acquired from the front, rear, side, or corner regions of the vehicle to a user, thereby protecting the vehicle and objects from autonomous driving or surrounding safety. A plurality of optical systems of the camera module according to the embodiments of the invention may be installed in a vehicle to enhance safety regulations, autonomous driving functions, and convenience using an Advanced Driving Assistance System (ADAS). The optical system of the camera module may also be applied in a vehicle as a control component for a lane keeping assistance system (LKAS), lane departure warning system (LDWS), or driver monitoring system (DMS). The optical system and the camera module having the same disclosed in the embodiments of the invention, as a camera module for a driver monitoring system (DMS), can achieve stable optical performance even when the ambient temperature changes, provide a cost-competitive module, and ensure the reliability of vehicle components.

[0203] 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 may be combined or modified with other embodiments by a person skilled in the art to which the embodiment belongs. Therefore, such combinations and modifications are to be construed as falling within the scope of the present invention. Furthermore, while the above description focuses on the embodiments, these are merely examples and do not limit the present invention. A person skilled in the art to which the present invention belongs may make various modifications and applications not exemplified above within the scope of the present embodiments, provided that such modifications and applications do not deviate from the essential characteristics of the present embodiments. For example, each component specifically presented in the embodiments may be modified. Such modifications and variations are to be construed as falling within the scope of the present invention, as defined by the appended claims.

Claims

1. The first lens to the fifth lens are arranged in order from the object side, a composite power of the first lens and the second lens is negative; the composite power of the third lens to the fifth lens is positive, Among the first to fifth lenses, the effective diameter of the second lens is the smallest, an effective diameter of the first lens is larger than an effective diameter of the second lens and smaller than an effective diameter of the third to fifth lenses; The power of the third lens is the greatest among the first to fifth lenses, The optical system is such that the fourth lens has the second largest power among the first to fifth lenses.

2. The first lens to the fifth lens are arranged in order from the object side, a composite power of the first lens and the second lens is negative; the composite power of the third lens to the fifth lens is positive, Among the first to fifth lenses, the effective diameter of the second lens is the smallest, The power of the third lens is the greatest among the first to fifth lenses, an optical axis distance from the object side surface of the first lens to the sensor side surface of the second lens is in the range of 26% to 36% of an optical axial distance from the object side surface of the third lens to the sensor side surface of the fifth lens.

3. a first lens to a fifth lens arranged in order from the object side; a diaphragm disposed around the periphery between the first lens and the second lens; Among the first to fifth lenses, the effective diameter of the second lens is the smallest, the third lens has a positive power and has the largest power among the first to fifth lenses; The optical system is such that the power of the fourth lens is positive and greater than the powers of the first, second and fifth lenses.

4. Includes an image sensor the radius of curvature of the object side surface and the sensor side surface of the fourth lens is the same; 4. The optical system according to claim 1, wherein the fourth lens has the largest center thickness among the first to fifth lenses.

5. 4. The optical system according to claim 1, wherein a center-to-center distance between the third lens and the fourth lens is greater than a center-to-center distance between the first lens and the second lens and a center-to-center distance between the second lens and the third lens.

6. the center distance between the fourth lens and the fifth lens is the largest among the center distances between the first to fifth lenses; 4. The optical system according to claim 1, wherein the first to fifth lenses are arranged so as to be spaced apart from one another along the optical axis.

7. 4. The optical system according to claim 3, wherein the power of each of the two lenses having positive power and arranged successively on the sensor side of the aperture stop is at least twice as large as the absolute value of the power of the other lenses.

8. Includes an image sensor 4. The optical system according to claim 1, wherein an optical axial distance from the object side surface of the third lens to the image sensor arranged on the sensor side of the fifth lens is in a range of 75% to 85% of an optical axial distance from the object side surface of the first lens to the image sensor.

9. the first lens has a meniscus shape that bulges from the optical axis toward the object side, The optical system according to claim 1 , wherein the second lens has a meniscus shape that bulges from the optical axis toward the sensor.

10. the third lens has a convex shape on both sides at the optical axis, The optical system according to claim 9 , wherein the fourth lens has a convex shape on both sides on the optical axis.

11. The optical system according to claim 10 , wherein the fifth lens has a meniscus shape that bulges from the optical axis toward the sensor.

12. the first lens has aspherical surfaces on its object side and its sensor side; 12. The optical system according to claim 11, wherein the second to fifth lenses each have a spherical surface on the object side and a spherical surface on the sensor side.

13. 4. The optical system according to claim 1, wherein the effective diameters of the third to fifth lenses are smaller than the diagonal length of the image sensor.

14. 4. The optical system according to claim 1, wherein the refractive indexes of the third and fourth lenses are higher than the average of the refractive indexes of the first to fifth lenses.

15. 4. The optical system according to claim 1, wherein the first to fifth lenses are made of glass, and the object-side and sensor-side surfaces are provided without critical points.

16. S7SagD1 is sag data at a point spaced a first distance from the center of the fourth lens on the object side, S8SagD1 is sag data at a point spaced the first distance from the center of the fourth lens on the sensor side, 4. The optical system according to claim 1, wherein the following formula is satisfied: |S7SagD1|-|S8SagD1|<0.2 mm.

17. the first distance is a point that is ½ of the average effective radius of the object side surface and the sensor side surface of the fourth lens, 17. The optical system of claim 16, wherein the formulas S7SagD1>0 and S8SagD1<0 are satisfied.

18. a maximum distance in the optical axis direction from a straight line orthogonal to the optical axis on the object side surface of the fifth lens to the object side surface of the fifth lens is Max_Sag51; a maximum distance in the optical axis direction from a straight line perpendicular to the optical axis on the sensor side surface of the fifth lens to the sensor side surface of the fifth lens is Max_Sag52; The optical system according to claim 1 , wherein the formula: |Max_Sag52|<|Max_Sag51| is satisfied.

19. 19. The optical system of claim 18, satisfying the formulas: Max_Sag51<0 and Max_Sag51<0.

20. The optical system according to any one of claims 1 to 3, The optical axis distance from the object side of the first lens to the image sensor is TTL, The total number of lenses is nL, The number of aspherical lenses among the first to fifth lenses is nASL, Half the diagonal length of the image sensor is ImgH, Formula: 3 <TTL / ImgH<5 Formula: 0 <nASL / nL<0.5 A camera module that satisfies the above.

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