Optical system and imaging device module

Abstract

An optical system disclosed in an embodiment of the present invention comprises: an image sensor; and first to fourth lenses aligned from the object toward the image sensor along the optical axis, in which the first lens has a positive refractive power, the second lens has a negative refractive power, the third lens has a positive refractive power, at least two of the first to fourth lenses are plastic lenses, the refractive index of the first lens is 1.7 or more, and the refractive index of the second lens is 1.7 or more. And an object-side surface and a sensor-side surface of a lens closest to the image sensor among the first to fourth lenses may include a critical point between the optical axis and the edge.

Description

Technical Field

[0001] Embodiments of the present invention relate to an optical system and a camera module including the optical system. Background Art

[0002] ADAS (Advanced Driver Assistance System) is an advanced driver assistance system that assists a driver in driving, and it is composed of sensing a situation ahead, judging a situation based on the sensing result, and controlling a vehicle behavior based on the situation judgment.

[0003] Due to the rapid growth of ADAS around the world, Driver Monitoring System (DMS) is quickly becoming an important safety feature.

[0004] The camera device linked to the DMS of the advanced driver assistance system is placed inside the vehicle and can detect the conditions of the driver and passengers. For example, the camera device can shoot the driver at a position adjacent to the driver and can detect the driver's health condition, whether he or she is sleepy, whether he or she is drinking, etc. In addition, the camera device can shoot the passenger at a position adjacent to the passenger and can detect whether the passenger is sleeping, whether he or she is healthy, etc., and can provide information about the passenger to the driver.

[0005] The most important element for obtaining an image from a camera is an imaging lens that forms the image. Recently, interest in high definition and high resolution, etc. has been increasing, and in order to achieve this, research on an optical system including a plurality of lenses is being conducted. However, when the camera is exposed to a harsh environment such as high temperature, low temperature, moisture or high humidity outside or inside a vehicle, there is a problem that the characteristics of the optical system change. In this case, the camera has a problem that it is difficult to uniformly derive excellent optical characteristics and aberration characteristics. Therefore, a new optical system and camera that can solve the above-mentioned problems are needed. Summary of the invention

[0006]

Technical issues

[0007] Embodiments may provide an optical system and a camera module with improved optical characteristics. The present embodiment provides an optical system and a camera module with excellent optical performance in a low to high temperature environment. Embodiments provide an optical system and a camera module capable of preventing or minimizing changes in optical characteristics within various temperature ranges. Embodiments may be provided for a camera used for a vehicle interior or a DMS.

[0008]

Technical Solution

[0009] An optical system according to an embodiment of the present invention includes: an image sensor; and first to fourth lenses, which are aligned along an optical axis from an object toward the image sensor, wherein the optical power of the first lens is positive, the optical power of the second lens is negative, the optical power of the third lens is positive, and at least two of the first to fourth lenses are plastic lenses, and the refractive index of the first lens is 1.7 or greater, and the object side surface and the sensor side surface of the lens closest to the image sensor among the first to fourth lenses may include a critical point between the optical axis and the edge.

[0010] According to an embodiment of the present invention, an optical system includes at least two plastic lenses and at least two glass lenses, wherein the optical focal length of the lens closest to the object side is positive, the composite optical focal length of the remaining lenses except the lens closest to the object side is positive, the lens with the thinnest thickness on the optical axis among the lenses can be one of the glass lenses, and the lens with the thickest thickness on the optical axis among the lenses can be one of the plastic lenses.

[0011] In an embodiment of the present invention, the lens having the thickest thickness on the optical axis may be a plastic lens closest to the glass lens. The object-side surface and the sensor-side surface of the lens located farthest from the object may include a critical point between the optical axis and the edge.

[0012] In an embodiment of the present invention, the refractive index of the lens closest to the object may be 1.7 or greater. The glass lenses may be the two lenses closest to the object.

[0013] In an embodiment of the present invention, each of the glass lenses adjacent to the object may have a meniscus shape convex toward the object side on the optical axis. In an embodiment of the present invention, the glass lens is a spherical lens, the plastic lens is an aspherical lens, the glass lens closest to the plastic lens may have a meniscus shape convex toward the sensor side on the optical axis, and the plastic lens closest to the glass lens may have a meniscus shape convex toward the sensor side on the optical axis.

[0014] According to an embodiment of the present invention, the sum of the thicknesses of the glass lenses on the optical axis is ΣGL_CT, and the optical axis distance from the object-side surface of the first lens to the sensor-side surface of the fourth lens is TD, and the following formula may be satisfied: 0.15≤ΣGL_CT / TD≤0.25.

[0015] An optical system according to an embodiment of the present invention includes: a lens of a first material, the lens of the first material being arranged continuously along an optical axis; and a lens of a second material, the lens of the second material being arranged continuously on the sensor side of the lens of the first material along the optical axis, wherein the lens of the first material includes a lens having an aspherical surface and a lens having a spherical surface, and the lens of the second material includes a lens having an aspherical surface, and the first material is different from the second material, and an average value of a center thickness of the lens of the first material may be greater than an average value of a center thickness of the lens of the second material.

[0016] According to an embodiment of the present invention, the first material may be a glass material, and the second material may be a plastic material.

[0017] According to an embodiment of the present invention, an average refractive index of the lens of the first material is greater than an average refractive index of the lens of the second material, and an average effective diameter of the lens of the first material may be greater than an average effective diameter of the lens of the second material.

[0018] According to an embodiment of the present invention, a number of the lenses of the first material is greater than a number of the lenses of the second material, and a difference between the number of the lenses of the first material and the number of the lenses of the second material may be less than the number of the lenses of the second material.

[0019] According to an embodiment of the present invention, at least two of the lenses of the first material include cemented lenses joined to each other, and the cemented lenses may include a lens having a positive refractive power and a lens having a negative refractive power.

[0020] An imaging device module according to an embodiment of the present invention includes: an image sensor; first to fourth lenses, the first to fourth lenses being aligned with an optical axis from an object toward the image sensor; and an optical filter, the optical filter being between the image sensor and the fourth lens, wherein a center thickness of the third lens is greater than a sum of center thicknesses of each of the first lens and the third lens, an effective diameter of each of the first to third lenses is less than a diagonal length of the image sensor, at least one of the first to fourth lenses is a spherical lens, and at least one of the first to fourth lenses is an aspherical lens, a distance from a center of an object-side surface of the first lens to a surface of the image sensor is TTL, a total effective focal length is F, and a half of the diagonal length of the image sensor is ImgH, and the imaging device module may satisfy Equation 1: 1 mm ≤ F ≤ 10 mm, Equation 2: 1 mm < TTL / ImgH < 5 mm, and Equation 3: TTL ≤ 10 mm.

[0021]

Advantages of the Invention

[0022] The optical system and the camera module according to the embodiment may have improved optical characteristics. Specifically, in the optical system according to the embodiment, the plurality of lenses may have set thickness, optical power, and spacing with adjacent lenses. Therefore, the optical system and the camera module according to the embodiment may have improved MTF characteristics, aberration control characteristics, resolution characteristics, etc. within a set field of view, and may have good optical performance in the periphery of the field of view.

[0023] In addition, the optical system and the camera module according to the embodiment can have good optical performance in a temperature range from low temperature (about -20°C to -40°C) to high temperature (85°C to 105°C). Specifically, the multiple lenses included in the optical system can have set materials, optical focal lengths, and refractive indices. Therefore, even if the focal length of each lens changes due to changes in refractive index according to temperature changes, the lenses can compensate for each other. That is, the optical system can effectively perform power distribution in a temperature range from low temperature to high temperature, and can prevent or minimize changes in optical characteristics in a temperature range from low temperature to high temperature. Therefore, the optical system and the camera module according to the embodiment can maintain improved optical characteristics in various temperature ranges.

[0024] In addition, the optical system and the camera module according to the embodiment can meet the set field of view and achieve excellent optical characteristics by mixing aspherical lenses and spherical lenses. This allows the optical system to provide a thinner vehicle camera module. Therefore, the optical system and the camera module can be provided for various applications and equipment, and can have excellent optical characteristics even in harsh temperature environments, such as when exposed to the outside of the vehicle or the inside of the vehicle at high temperatures in summer. The embodiment can improve the reliability of the camera used for the interior of the vehicle or DMS. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a side cross-sectional view of an optical system and an image pickup device module having the optical system according to a first embodiment.

[0026] Figure 2 It is used to explain the Figure 1 A side cross-sectional view showing the relationship between the nth lens and the n-1th lens.

[0027] Figure 3 It is shown Figure 1 A table of lens characteristics of an optical system.

[0028] Figure 4 It is shown Figure 1 Table of aspheric coefficients of lenses in the optical system.

[0029] Figure 5 It is shown Figure 1 A table of the center thickness of each lens in an optical system and the center distances between adjacent lenses.

[0030] Figure 6 It shows that according to Figure 1 A table of CRA (chief ray angle) data at room temperature, low temperature, and high temperature for the position of the image sensor in the optical system.

[0031] Figure 7 It is shown Figure 1 A graph of the diffraction MTF (Modulation Transfer Function) data of an optical system at room temperature.

[0032] Figure 8 It is shown Figure 1 A graph of the diffraction MTF data of an optical system at low temperatures.

[0033] Fig. 9 It is shown Figure 1 A graph of the diffraction MTF data of an optical system at high temperature.

[0034] Fig.10 It is shown Figure 1 A graph of data on the aberration characteristics of an optical system at room temperature.

[0035] Fig.11 It is shown Figure 1 This is a graph showing the aberration characteristics of an optical system at low temperatures.

[0036] Fig.12 It is shown Figure 1 This is a graph showing data on the aberration characteristics of an optical system at high temperatures.

[0037] Fig.13 is a side cross-sectional view of an optical system and an image pickup device module having the optical system according to a second embodiment.

[0038] Fig.14 It is shown Fig.13 A table of lens characteristics of an optical system.

[0039] Fig.15 It is shown Fig.13 Table of aspheric coefficients of lenses in the optical system.

[0040] Fig.16 It is shown Fig.13 A table showing the thickness of each lens of an optical system and the spacing between adjacent lenses.

[0041] Fig.17 It shows that according to Fig.13Table of CRA data for the position of the image sensor in the optical system at room temperature, low temperature, and high temperature.

[0042] Fig.18 It is shown Fig.13 A graph of the diffraction MTF data of an optical system at room temperature.

[0043] Fig.19 It is shown Fig.13 A graph of data on the aberration characteristics of an optical system at room temperature.

[0044] Fig. 20 : is a table showing data on relative illuminance according to the height of the image sensor according to the first embodiment and the second embodiment.

[0045] Fig.21 is a side cross-sectional view of an optical system and a camera module having the same according to an embodiment.

[0046] Fig. 22 It is used to explain the Fig.21 A side cross-sectional view showing the relationship between the nth lens and the n-1th lens.

[0047] Fig.23 It is shown Fig.21 A table of lens characteristics of an optical system.

[0048] Fig.24 It is shown Fig.21 Table of aspheric coefficients of lenses in the optical system.

[0049] Fig.25 It is shown Fig.21 A table showing the thickness of each lens of an optical system and the spacing between adjacent lenses.

[0050] Fig.26 It is shown Fig.21 A table of Sag values ​​of the lens surfaces of the third to sixth lenses in the optical system.

[0051] Fig. 27 It shows that according to Fig.21 Table of CRA data for the position of the image sensor in the optical system at room temperature, low temperature, and high temperature.

[0052] Fig.28 It is shown Fig.21 A graph of the diffraction MTF data of an optical system at room temperature.

[0053] Fig.29 It is shown Fig.21 A graph of the diffraction MTF data of an optical system at low temperatures.

[0054] Fig.30 It is shown Fig.21 A graph of the diffraction MTF data of an optical system at high temperature.

[0055] Fig.31 It is shown Fig.21 A graph of data on the aberration characteristics of an optical system at room temperature.

[0056] Fig.32 It is shown Fig.21 This is a graph showing the aberration characteristics of an optical system at low temperatures.

[0057] Fig.33 It is shown Fig.21 This is a graph showing data on the aberration characteristics of an optical system at high temperatures.

[0058] Fig.34 is a graph showing relative illumination according to the height of an image sensor according to an embodiment.

[0059] Fig.35 is an example of a vehicle having an optical system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0060] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The technical spirit of the present invention is not limited to some embodiments to be described, and can be implemented in various other forms, and one or more of the components can be selectively combined and replaced to be used within the scope of the technical spirit of the present invention. In addition, the terms (including technical terms and scientific terms) used in the embodiments of the present invention, unless otherwise specified and clearly described, can be interpreted with the meaning that can be generally understood by ordinary technicians in the field to which the present invention belongs, and commonly used terms such as terms defined in dictionaries should be able to interpret their meanings in consideration of the contextual meaning of the relevant technology.

[0061] The terms used in the embodiments of the present invention are used to explain the embodiments and are not intended to limit the present invention. In this specification, unless otherwise specifically stated in the phrase, the singular form may also include the plural form, and in the case of describing at least one (or one or more) of A and (and) B, C, it may include one or more of all combinations that can be combined with A, B and C. When describing the components of the embodiments of the present invention, terms such as the first, second, A, B, (a) and (b) may be used. Such terms are only used to distinguish components from other components and may not be determined by terms such as the properties, sequence or process of the corresponding constituent elements. And when describing a component "connected", "coupled" or "engaged" to another component, the description may include not only direct connection, coupling or engagement to another component, but also "connected", "coupled" or "engaged" by another component between the component and another component. In addition, in the case of being described as being formed or arranged on "above (upper)" or "below (lower)" of each component, the description may include not only the situation that two components are in direct contact with each other, but also the situation that one or more other components are formed or arranged between the two components. In addition, when expressed as "above (up)" or "below (lower)", it can refer to the downward direction as well as the upward direction relative to an element. Several embodiments described below can be combined with each other unless it is specifically stated that they cannot be combined with each other. In addition, unless otherwise specified, the description of other embodiments can be applied to the parts omitted from the description of any one of the several embodiments.

[0062] In the description of the present invention, "object side surface" may refer to the surface of the lens facing the object side relative to the optical axis OA, and "sensor side surface" may refer to the surface of the lens facing the imaging surface (image sensor) relative to the optical axis. The convex surface of the lens may mean a convex shape on the optical axis or the paraxial region, and the concave surface of the lens may mean a concave shape on the optical axis or the paraxial region. The radius of curvature, the center thickness, and the distance between the lenses described in the table of lens data may mean the value on the optical axis, and the unit is mm. The vertical direction may mean the direction perpendicular to the optical axis, and the end of the lens surface or the lens may mean the end or edge of the effective area of ​​the lens through which the incident light passes. Depending on the measurement method, the size of the effective diameter on the lens surface may have a measurement error of up to ±0.4mm. The paraxial region refers to a very narrow area near the optical axis, and is an area where the distance of the light falling from the optical axis OA is almost 0. In the following, the optical axis may include the center of each lens or a very narrow area near the optical axis.

[0063] like Figure 1 and Fig.13As shown, the optical system 1000 according to the first and second embodiments of the present invention may include a plurality of lens groups LG1 and LG2. The plurality of lens groups LG1 and LG2 may include a first lens group LG1 and a second lens group LG2, and the first lens group LG1 and the second lens group LG2 are sequentially arranged along the optical axis OA from the object side toward the image sensor 300. The number of lenses in each of the first lens group LG1 and the second lens group LG2 may be different from each other. 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, it may be greater than twice the number of lenses in the first lens group LG1 or greater than three times the number of lenses in the first lens group LG1. The first lens group LG1 may have two or fewer lenses. The first lens group LG1 may preferably have one lens. The second lens group LG2 may include two or more lenses or three or more lenses. The second lens group LG2 may include three lenses. The optical system 1000 may include n lenses, and 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. n is an integer less than or equal to 5, for example, 3 to 5.

[0064] The first lens group LG1 may include at least one lens made of glass. The first lens group LG1 may have the lens closest to the object side set as a lens made of glass. Such a glass material has a small amount of expansion and contraction changes due to external temperature changes, and the surface is not easily scratched, so that surface damage can be prevented. The lens material of the second lens group LG2 may include at least one lens made of glass and at least one lens made of plastic. Preferably, when the number of glass lenses is nGL and the number of plastic lenses is nPL, the second lens group LG2 may satisfy the following condition: nGL < nPL. The optical system 1000 may have the same number of glass lenses and plastic lenses.

[0065] The second lens group LG2 may include at least one spherical lens and at least one aspherical lens. The number of aspherical lenses in the second lens group LG2 may be greater than the number of spherical lenses. Here, the spherical lens is a lens whose object side surface and sensor side surface are spherical on the optical axis, and the aspherical lens is a lens whose object side surface and sensor side surface are aspherical. Here, the nth lens is the lens closest to the image sensor 300, and may be an aspherical lens or a plastic lens to prevent degradation of optical performance. As another example, the aspherical lens may be made of a glass molded material. A glass molded material lens is a lens that is injection molded using a glass material to have an aspherical surface. The number of aspherical lenses in the second lens group LG2 may be at least twice the number of spherical lenses. Aspherical lenses may prevent spherical aberrations within the optical system 1000, and since aberrations do not occur even when the effective diameter increases, miniaturization and weight reduction of the camera module may be possible.

[0066] The optical system 1000 can compensate for the heat in the lens barrel by arranging a mixture of glass and plastic materials, and can suppress the degradation of optical characteristics due to temperature changes. In addition, since the optical system 1000 includes at least one plastic lens or at least one aspherical lens, the occurrence of various aberrations can be suppressed.

[0067] In the optical system 1000, a lens having a maximum Abbe number may be located in the second lens group LG2, and a lens having a maximum refractive index may be located in the first lens group LG1. The above-mentioned maximum Abbe number is 55 or greater, and the maximum refractive index may be 1.70 or greater. The lens having the above-mentioned maximum Abbe number may reduce dispersion, and the lens having the maximum refractive index may increase dispersion of incident light. The refractive index of the i-th lens is Ndi, the Abbe number of the i-th lens is Adi, and the value of the following condition: Ndi*Adi may be maximum when i is 2. In addition, when i=1, 2, the value of the following condition: Ndi*Adi is 45 or greater, and when i=3, 4, the value of the following condition: Ndi*Adi is less than 50. The lens having a minimum effective diameter in the optical system 1000 may satisfy the value of the following condition Ndi*Adi satisfies: 80<(Ndi*Adi)<140, and * indicates multiplication.

[0068] The lens having the largest effective diameter within the lens portions 100 and 100A is an aspherical lens and can be arranged closest to the image sensor 300. The aspherical lens having the largest effective diameter can refract light to the entire area of the image sensor 300. Additionally, the lens having the largest effective diameter can be a plastic lens and can be a glass lens having the smallest effective diameter. The lens having the smallest effective diameter can be arranged between the plastic lens and the glass lens. The lens having the largest effective diameter can be arranged between the plastic lens or the aspherical lens and the image sensor. Additionally, the lens closest to the object can be a spherical lens or a glass lens. The effective diameter of each lens can be the diameter of the effective area onto which the 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. By further mixing the aspherical lens into the optical system 1000, embodiments of the present invention can reduce the weight of the imaging device module, provide a lower manufacturing cost, and suppress the deterioration of optical characteristics due to temperature changes.

[0069] Each of the lenses can include an effective area and an ineffective area. The effective area can be the area through which the light incident on each of the lenses passes. In other words, the effective area can be defined as the effective area or effective diameter where the incident light is refracted to achieve optical characteristics. The end of the ineffective area can be the area fixed to a lens barrel (not shown) that houses the lens.

[0070] In the optical system 1000, the TTL (Total Top Length or Total Track Length) can be 1 times larger than ImgH, for example, 1 times larger than ImgH and 5 times smaller than ImgH. Preferably, the following condition can be satisfied: 1 < TTL / ImgH < 3. The TTL is the optical axis distance from the center of the object-side surface of the first lens to the surface of the image sensor 300. ImgH is half of the diagonal length of the image sensor 300 on the optical axis OA. In the optical system 1000, the effective focal length (EFL) is 10 mm or less and the diagonal field of view (FOV) is greater than 45 degrees, such that the optical system can be provided as a standard optical system in a vehicle imaging device module. That is, for the diagonal field of view, the focal length can be reduced to 10 mm or less. For example, the optical system and the imaging device module according to embodiments can be applied to the imaging device module of a DMS provided inside a vehicle. The optical system 1000 can have a value of TTL / (2*ImgH) greater than 0.5, for example, greater than 0.5 and less than 2.5 or 0.5 < TTL / (2*ImgH) < 1.5. By setting the value of TTL / (2*ImgH) to less than 1.5, the optical system 1000 can provide an optical system for driver monitoring. The total number of lenses in the first lens group LG1 and the second lens group LG2 is 5 or less. Therefore, the optical system 1000 can provide an image without exaggeration or distortion for the image being formed.

[0071] The length of the image processor 300 is the maximum length of a diagonal line orthogonal to the optical axis OA. The number of lenses having an effective diameter greater than the diagonal length of the image sensor 300 in the optical system 1000 is 2 or less or 1 or less, and the number of lenses having an effective diameter less than the length of the image sensor 300 may be 2 or more or 3 or more. The diagonal length of the image sensor 300 may be greater than the diameter of a spherical lens or a glass lens. The diagonal length of the image sensor 300 may be less than or greater than the diameter of at least one of an aspherical lens or a plastic lens. Preferably, half of the diagonal length of the image sensor 300 may be greater than the minimum effective diameter of the lens.

[0072] In the lens sections 100 and 100A, the first lens may have an effective diameter that is smaller than the effective diameter of the last lens closest to the image sensor 300, and may be provided with a glass material having a high refractive index. Therefore, the center thickness of the first lens of the optical system may be set thinner than the center thickness of the last lens, and the refraction angle and dispersion may be increased. The effective diameter of the lens may gradually decrease from the first lens section to the last spherical lens, and may gradually increase from the last spherical lens section to the last aspherical lens. By controlling the effective diameter size of each lens, it is possible to control the light incident on the image sensor 300 having at least 2 megabyte 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.

[0073] The optical system 1000 may include an aperture stop ST. The aperture stop ST may control the amount of light incident on the optical system 1000. The aperture stop ST may be arranged between any two lenses of the lens portions 100 and 100A. In a lens arranged between an object and the aperture stop ST, the effective diameter of the lens surface tends to become smaller as it goes from the object side to the aperture stop ST. In a lens arranged between the aperture stop ST and the image sensor 300, the effective diameter of the lens surface tends to become larger as it goes from the aperture stop ST to the sensor side. The meaning of "the effective diameter of the lens tends to become larger as it goes from the aperture stop ST to the sensor side" may include: in a lens arranged between the aperture stop ST and the image sensor 300, the effective diameter of the lens surface gradually becomes larger or smaller as it goes from the aperture stop ST to the sensor side. As another example, the aperture stop ST may be arranged around the object side surface of the lens closest to the object side among the lenses of the second lens group LG2. Alternatively, the aperture stop ST may be arranged around the object-side surface of the object-side lens of the first lens group LG1. Alternatively, at least one lens selected from a plurality of lenses may be used as the aperture stop. Specifically, the object-side surface or the sensor-side surface of one lens selected from the lenses of the optical system 1000 may be used as the aperture stop for controlling the amount of light.

[0074] The optical axis distance between the first lens group LG1 and the second lens group LG2 may be the optical axis 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 axis distance between the first lens group LG1 and the second lens group LG2 may be the center distance between adjacent spherical lenses. In addition, the optical axis distance between the first lens group LG1 and the second lens group LG2 may be smaller than the center distance between the object side spherical lens and the sensor side aspherical lens. The optical axis distance between the first lens group LG1 and the second lens group LG2 may be greater than the center distance between the aspherical lenses and the aspherical lenses.

[0075] The optical axis distance between the first lens group LG1 and the second lens group LG2 can be less than 1 times the optical axis distance of the first lens group LG1, for example, greater than 0.5 times the optical axis distance of the first lens group LG1 and less than 0.8 times the optical axis distance of the first lens group LG1. The optical axis distance between the first lens group LG1 and the second lens group LG2 can be less than 0.5 times the optical axis distance of the second lens group LG2, for example, greater than 0 times and less than 0.3 times. The optical axis distance of the first lens group LG1 is the optical axis distance from the object-side surface to the sensor-side surface. The optical axis distance of the second lens group LG2 is the optical axis distance between the object-side surface of the lens closest to the object side in 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 can include a lens located closer to the object side than the aperture stop ST, and the second lens group LG2 can include a lens located closer to the sensor side than the aperture stop ST. The first lens group LG1 and the second lens group LG2 can 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 can have a concave shape on the optical axis, and the object-side surface of the second lens group LG2 can have a convex shape on the optical axis and can face each other.

[0076] The first lens group LG1 can have a positive (+) optical power, and the second lens group LG2 can have a positive (+) optical power. The lens closest to the object side in the first lens group LG1 can have a positive (+) optical power, and the lens closest to the sensor side among the lenses of the second lens group LG2 can have a negative (-) optical power. When the focal length of the first lens group LG1 is F_LG1 and the focal length of the second lens group LG2 is F_LG2, F_LG1 < F_LG2 can be satisfied. Here, when the combined focal length of the first lenses 101 and 111 and the second lenses 102 and 112 in the optical system 1000 is set to F12, and the combined focal length of the third lenses 103 and 113 and the fourth lenses 104 and 114 is set to F34, the following conditions can be satisfied: F12 < F34, and the conditions F13, F47 > 0 can be satisfied. Additionally, the following conditions can be satisfied: F_LG1 < F12 < F_LG2 and F_LG1 < F34 < F_LG2. Here, F_LG1 is the focal length of the first lenses 101 and 111 and can be defined as F1, and F_LG2 is the combined focal length of the second lenses 102 and 112 to the fourth lenses 104 and 114 and can be defined as F24. Additionally, the number of lenses with a negative (-) optical power on the optical system 1000 can be equal to the number of lenses with a positive (+) optical power. The number of lenses with a negative (-) optical power can be 60% or less of the total number of lenses, for example, in the range of 40% to 60%.

[0077] The lens portions 100 and 100A may be a mixture of spherical lenses and aspherical lenses. The average effective diameter of the glass lens may be smaller than the average effective diameter of the plastic lens, and the difference between the average effective diameter of the glass lens and the average effective diameter of the plastic lens may be 0.5 mm or greater, for example, in the range of 0.5 mm to 2.5 mm. The plastic lens may be an aspherical lens, and the glass lens may be a spherical lens. The number of lenses of the plastic lens may be 60% or less of the total number of lenses, for example, in the range of 40% to 60%. Therefore, when two or more plastic lenses are arranged in a camera module, the weight of the camera module may be reduced and the optical characteristics may be improved. In addition, the difference in effective diameter between the plastic lens and the glass lens may be reduced, thereby preventing degradation of the components.

[0078] The first lens group LG1 may refract light incident through the object side in the optical axis direction, and the second lens group LG2 may refract light emitted through the first lens group LG1 to the image sensor 300. The optical axis distance between the first lens group LG1 and the second lens group LG2 may be less than 1 mm, for example, 0.7 mm or less.

[0079] The average Abbe number of the spherical material lenses in the lens parts 100 and 100A can be greater than the average Abbe number of the aspherical lenses. Since the lens closest to the object has a low Abbe number and a high refractive index, it can increase the dispersion of incident light in an optical system with five or fewer lenses and widen the field of view compared to the focal length.

[0080] The sum of the refractive indexes of the lenses of the lens portions 100 and 100A of the embodiment may be 8 or less, for example, in the range of 5 to 8, and the average value of the refractive index may be in the range of 1.67 to 1.77. The sum of the Abbe numbers of each of the lenses may be 200 or less, for example, in the range of 100 to 200, and the average value of the Abbe numbers may be 45 or less, for example, in the range of 25 to 45. The sum of the center thicknesses of the entire lens may be 6 mm or less, for example, in the range of 3 mm to 6 mm or 3.5 mm to 5 mm. The average value of the center thicknesses of the entire lens 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 distances between the lenses on the optical axis OA may be 2.5 mm or less, for example, in the range of 1 mm to 2.5 mm or 1.2 mm to 2.1 mm, and may be less than the sum of the center thicknesses of the lenses. In addition, the average value of the effective diameter of each lens surface of the lens portions 100 and 100A may be set to 5 mm or less, for example, in the range of 2 mm to 5 mm. The maximum difference and the minimum difference of the effective diameter can have a difference of 3 mm or less. Therefore, an optical system in which the effective diameter difference of each lens surface is not large can be provided, and the assemblability of the lens assembled in the lens barrel can be improved.

[0081] In the lens sections 100 and 100A, when the number of aspherical lenses 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 optical power is Mc, the following conditions can be satisfied: Mb ≤ Ma < Mb, and preferably, Ma and Mb can be the same. In the lens sections 100 and 100A, the number of lens surfaces having an aspherical surface 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 optical power is Mc, then the following conditions can be satisfied: Mc < Ma1 < Mb1. The lens surface is the object-side surface and the sensor-side surface of each lens. In the lens sections 100 and 100A, the number of spherical lenses is Ga, the number of lenses having an effective diameter larger than the diagonal length of the image sensor 300 is Gb, and the number of lenses having a positive optical power is Gc, then the following conditions can be satisfied: Gb ≤ Ga ≤ Gc, and preferably, Ga and Gc can be the same.

[0082] If the average value of the effective diameters of the glass lenses or spherical lenses is GL_CA_Aver, and the average value of the effective diameters of the plastic lenses or aspherical lenses is PL_CA_Aver, then the following condition can be satisfied: GL_CA_Aver < PL_CA_Aver. If the average value of the center thicknesses of the glass lenses or spherical lenses is GL_CT_Aver, and the average value of the center thicknesses of the plastic lenses or aspherical lenses is PL_CT_Aver, then the following condition can be satisfied: GL_CT_Aver < PL_CT_Aver. If the average value of the refractive indices of the glass lenses or spherical lenses is GL_Nd_Aver, and the average value of the refractive indices of the plastic lenses or aspherical lenses is PL_Nd_Aver, then the following condition can be satisfied: PL_Nd_Aver < GL_Nd_Aver. The average Abbe number of the glass lenses or spherical lenses is GL_Ad_Aver, and the average Abbe number of the plastic lenses or aspherical lenses is PL_Ad_Aver, such that the following condition can be satisfied: PL_Ad_Aver < GL_Ad_Aver.

[0083] The F number of the optical system or camera module may be 2.4 or less, for example, in the range of 1.4 to 2.4 or in the range of 1.8 to 2.2. The maximum field of view (diagonal FOV) of the optical system may be less than 75 degrees, for example, in the range of greater than 45 degrees and less than 75 degrees, or in the range of 50 degrees to 70 degrees. The vehicle optical system may have a horizontal field of view FOV_H in the Y-axis direction that may be greater than 40 degrees and less than 60 degrees, for example, in the range of 45 degrees to 55 degrees. In addition, the vertical field of view is set at an angle smaller than the horizontal field of view, and may be less than 51 degrees, for example, in the range of 31 degrees to 51 degrees. At this time, the sensor length in the horizontal direction Y may be 4.800 mm ± 0.5 mm, and the sensor height in the vertical direction X may be 3.900 mm ± 0.5 mm. The horizontal field of view FOV_H is a field of view based on the horizontal length of the sensor. Therefore, changes in the focused imaging position due to temperature changes can be suppressed, and a vehicle camera device in which various aberrations are well corrected can be provided. When the diagonal field of view of the optical system 1000 is 50 to 70 degrees, when there is at least one glass lens and at least one plastic lens in the optical system, the center thickness of the plastic lens arranged on the sensor side of the glass lens can be the thickest. In addition, the average value of the center thickness of the plastic lens can be set to be thicker than the average value of the center thickness of the glass lens. Therefore, the number of plastic lenses in the optical system, the center thickness of the plastic lens, the plastic lens with an aspherical surface, and at least one plastic lens with a critical point can reduce the influence of aberrations such as spherical aberration, field curvature, and distortion caused by the glass lens on optical performance, and can reduce the change in optical performance caused by temperature changes from low temperature to high temperature. In addition, by applying one or more plastic lenses in the optical system, it can be beneficial to reduce manufacturing costs and weight, and the processing of plastic lenses can be easier than that of glass lenses. In addition, by applying a plastic lens with an aspherical surface for aberration correction and increasing the thickness of the plastic lens, the sensitivity of the aspherical shape can be reduced, and the assembly in the lens barrel can be improved.

[0084] The optical system 1000 or the 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 portions 100 and 100A. The image sensor 300 may include a device capable of detecting incident light, such as a CCD (charge coupled device) or a CMOS (complementary metal oxide semiconductor). Here, the diagonal length of the image sensor 300 may be 87% or more of the maximum effective diameter of the lens, for example, in the range of 87% to 107%, and for example, in the range of 90% to 105%.

[0085] The optical system 1000 or the camera module may include an optical filter 500. The optical filter 500 may be disposed between the second lens group LG2 and the image sensor 300. The optical filter 500 may be placed between the lens closest to the sensor side among the lenses of the lens parts 100 and 100A and the image sensor 300. For example, the optical system 100 may be disposed between the last lens and the image sensor 300. The cover glass 400 is disposed between the optical filter 500 and the image sensor 300, and may protect the upper portion of the image sensor 300 and prevent the reliability of the image sensor 300 from being deteriorated. The cover glass 400 may be removed.

[0086] The optical filter 500 may include an infrared filter or an infrared cut filter. The optical filter 500 may pass light of a set wavelength band and filter light of 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. In addition, the optical filter 500 may transmit visible light and reflect infrared light. The optical filter 500 may transmit a wavelength of 920 nm or more, and for example, may transmit a wavelength band of 920 nm to 960 nm.

[0087] Since the embodiment is an optical system applied to a vehicle camera device, even if the first lenses 101 and 111 are designed using an aspherical lens and a spherical lens together, the first lenses 101 and 111 can also be provided as glass materials. This has the following advantages: compared with plastic materials, glass materials are scratch-resistant and insensitive to external temperature. Since the first lens has a convex shape facing the driver inside the vehicle, it is possible to more effectively prevent foreign matter accumulation or scratching, and improve the incident efficiency. Therefore, the reliability of the driving or monitoring camera module can be improved. The last lens in the lens portion 100 and 100A can be set to an aspherical lens made of plastic. Since the last lens is made of a plastic material having an aspherical surface, various aberrations can be corrected to reduce the impact on optical characteristics, and the total length (TTL) can be reduced. In addition, since the last lens is set to an aspherical lens, chromatic aberration can be corrected, and since it has a thicker thickness than a spherical lens, the assembly with the lens barrel can be improved. In addition, the last lens may refract light to the entire area of ​​the image sensor 300 through an aspherical sensor side surface having a critical point. The last lens has a gull-shaped cross section and may refract incident light to the entire area of ​​the image sensor 300. The gull-shaped shape is a shape in which the center and edge of the object side surface and the sensor side surface of the lens are convex, and the area between the center and the edge is concave. In addition, since the last lens is made of plastic, in order to increase the low refractive index or low refraction angle of the plastic lens, the last lens may have a lens surface having at least one critical point from the optical axis to the end of the effective area. The lens surface having a critical point may include the object side surface and / or the sensor side surface of the last lens.

[0088] The optical system 1000 according to the embodiment may further include a reflective member (not shown) for changing the optical path. The reflective member may be implemented as a prism that reflects the incident light of the first lens group LG1 toward the lens. Hereinafter, the optical system according to the embodiment will be described in detail.

[0089] Will refer to Figures 1 to 12 An optical system and a camera module according to a first embodiment of the present invention are described.

[0090] Reference Figures 1 to 3 , the optical system 1000 according to the first embodiment includes a lens portion 100, and the lens portion 100 may include first to fourth lenses 101 to 104. The first to fourth lenses 101 to 104 may be sequentially aligned along the optical axis OA, and incident light may pass through the first to fourth lenses 101 to 104 and the optical filter 500 to be incident on the image sensor 300.

[0091] The first lens 101 is a lens of the first lens group LG1 and is the lens closest to the object side. The fourth lens 104 is the lens closest to the image sensor 104 within the second lens group LG2 or the lens portion 100. The second to fourth lenses 102, 103, and 104 may be the second lens group LG2. As the combined focal lengths of the lenses, F12, F24, and F34 may satisfy the following conditions.

[0092] Condition 1: F12 < F34 < F24, Condition 2: F < F12, Condition 3: (F34 - F12) < (F12 - F)

[0093] The first lens 101 may have a positive (+) or negative (-) optical power on the optical axis OA. The first lens 101 may have a positive (+) optical power. The first lens 101 may include a plastic material or a glass material and may be, for example, a glass material. The first lens 101 made of a glass material may reduce the changes in the center position and the radius of curvature due to temperature changes according to the surrounding environment and may protect the incident side surface of the optical system 1000. On the optical axis, the first surface S1 on the object side of the first lens 101 may have a convex shape, and the second surface S2 on the sensor side may have a concave shape. The first lens 101 may have a meniscus shape that bulges toward the object side on the optical axis. Differently, the first surface S1 may have a concave shape on the optical axis OA, and the second surface S2 may have a convex shape on the optical axis OA. The first lens 101 may have the thickest thickness among the glass lenses so that it can prevent a reduction in rigidity due to external shocks, and due to the glass material, when the temperature changes to a low or high temperature, it can suppress changes in optical performance. Additionally, since a spherical surface is applied to the glass material, even if the thickness of the lens is designed to be thick, the change in the refractive index of light may not be large. Here, the thickness of the lens may be the center thickness. The first lens 101 has a convex first surface S1 and a concave second surface S2 on the optical axis so that incident light can be refracted in a direction close to the optical axis, and the center distance between the first lens 101 and the second lens 102 and the effective diameter of the second lens 102 may be reduced. Since the second lens 102 is arranged closest to the sensor side of the aperture stop ST, the second lens 102 may have the smallest effective diameter among the first lens 101 to the fourth lens 104.

[0094] The aperture stop ST may be provided around the sensor-side surface of the first lens 101. Alternatively, the aperture stop ST may be provided around the object-side or sensor-side surface of the second lens 102, or around the object-side surface of the third lens 103. Since the aperture stop ST is provided on the periphery between the first lens 101 and the second lens 102, the center distance between the first lens 101 and the second lens 102 may not be increased, and the effective diameter difference between the first lens 101 and the second lens 102 may be reduced. The first lens 101 and the second lens 102 on both sides of the aperture stop ST may have optical powers of opposite signs.

[0095] The second lens 102 may be arranged between the first lens 101 and the third lens 103. The second lens 102 may have positive (+) or negative (-) optical power on the optical axis OA. The second lens 102 may have negative (-) optical power. The second lens 102 may include a plastic or glass material. For example, the second lens 102 may be set to a glass material. The object-side third surface S3 of the second lens 102 on the optical axis OA may be convex, and the sensor-side fourth surface S4 may be concave. The second lens 102 may have a meniscus shape convex from the optical axis toward the object side. Alternatively, the third surface S3 may be concave, and the fourth surface S4 may be convex. Alternatively, the second lens 102 may have a concave shape on both sides. The second lens 102 may be set to a spherical lens made of glass. The third surface S3 and the fourth surface S4 may be spherical.

[0096] The third lens 103 may have positive (+) or negative (-) optical power on the optical axis OA. The third lens 103 may have positive (+) optical power. The third lens 103 may include a plastic or glass material. For example, the third lens 103 may be a plastic material. On the optical axis, the fifth surface S5 on the object side of the third lens 103 may have a concave shape, and the sixth surface S6 on the sensor side may have a convex shape. The third lens 103 may have a meniscus shape convex from the optical axis toward the sensor side. Alternatively, the third lens 103 may have a meniscus shape convex from the object side, or a shape that is concave on both sides from the optical axis. The third lens 103 includes a plastic material and may be defined as a first aspherical lens. The fifth surface S5 and the sixth surface S6 may be aspherical on the optical axis, and the aspherical coefficients may be set to Figure 4 L3S1 and L3S2. At least one or both of the fifth surface S5 and the sixth surface S6 may be set to have no critical point from the optical axis OA to the end of the effective area. The center thickness of the third lens 103 may be the thickest among the lenses. The edge thickness of the third lens 103 may be the thickest among the lenses. Since the third lens 103 has the thickest thickness and has a convex meniscus shape toward the sensor on the optical axis, the effective diameter of the fourth lens 104 may be increased.

[0097] The fourth lens 104 may have positive (+) or negative (-) optical power on the optical axis OA. The fourth lens 104 may have negative optical power. The fourth lens 104 may include a plastic or glass material. For example, the fourth lens 104 may include a plastic material. The seventh surface S7 on the object side of the fourth lens 104 may be convex on the optical axis, and the eighth surface S8 on the sensor side may have a concave shape. The fourth lens 104 may have a meniscus shape that is convex toward the object side on the optical axis. Differently, the fourth lens 104 may have a meniscus shape that is convex toward the sensor side on the optical axis. The fourth lens 104 may be set to an aspherical lens made of a plastic material. The seventh surface S7 and the eighth surface S8 may be aspherical on the optical axis, and the aspherical coefficients may be set to Figure 4 L4S1 and L4S2.

[0098] The fourth lens 104 may be an aspheric lens closest to the image sensor 300. Since the aspheric lens is arranged closest to the image sensor 300, it is possible to prevent degradation of optical performance, improve aberration characteristics, and control the impact on resolution. In addition, since the aspheric lens is arranged closest to the image sensor 300, the aspheric lens may be insensitive to assembly tolerances compared to spherical lenses. In other words, being insensitive to assembly tolerances means that even if the assembly is slightly different from the design during assembly, the optical performance may not be significantly affected. Therefore, the effective diameter of the fourth lens 104 may be increased, or the center thickness or edge thickness may be increased. In other words, the effective diameter of the fourth lens 104 may have the largest effective diameter among the effective diameters of the lens. The center thickness or edge thickness of the fourth lens 104 may be greater than the center thickness or edge thickness of the glass lens.

[0099] Reference Figure 2, at least one of the seventh surface S7 and the eighth surface S8 of the fourth lens 104 may have a critical point. The seventh surface S7 of the fourth lens 104 may have a first critical point P1 from the optical axis OA to the end of the effective area. The sensor-side eighth surface S8 of the fourth lens 104 may have a second critical point P2 from the optical axis OA to the end of the effective area. The critical point is a point where the trend of the Sag value changes. That is, it is a point where the Sag value increases and then decreases, or a point where the Sag value decreases and then increases. The first critical point P1 of the seventh surface S7 may be located at a distance of 1.6 mm or less in a direction perpendicular to the optical axis based on the optical axis, for example, between a point of 0.9 mm and a point of 1.6 mm. Since the first critical point P1 is located closer to the optical axis than the second critical point P2, light incident through the seventh surface S7 may be refracted to the periphery of the eighth surface S8. The second critical point P2 of the eighth surface S8 may be located at a distance of 1.8 mm or more in a direction perpendicular to the optical axis, for example, between a point of 1.8 mm and a point of 2.4 mm. For example, the Sag values ​​on the seventh and eighth surfaces increase in a direction perpendicular to the optical axis until the first critical point and the second critical point, and then decrease toward the edge after the first critical point and the second critical point. The eighth surface S8 of the fourth lens 114 can refract light to the periphery of the image sensor 300 through the second critical point P2.

[0100] The Sag value is an optical axis distance between a straight line perpendicular to the center of each lens surface and the lens surface, and the Sag value has a positive value at a position closer to the sensor than the center of each lens surface, and has a negative value at a position closer to the object than the center of each lens surface. When expressed as an absolute value of the Sag value, the maximum value of Sag32 may be greater than the maximum values ​​of Sag31, Sag41, and Sag42. Sag32 is an optical axis distance between a straight line perpendicular to the center of the sensor-side surface of the third lens 103 and the object-side surface of the third lens 103, Sag42 is an optical axis distance between a straight line perpendicular to the center of the sensor-side surface of the fourth lens 104 and the sensor-side surface, and Sag41 is an optical axis distance between a straight line perpendicular to the center of the object-side surface of the fourth lens 104 and the object-side surface.

[0101] BFL (back focal length) is the optical axis distance from the image sensor 300 to the center of the sensor-side surface of the last lens. A tangent K1 passing through any point of the eighth surface S8 of the fourth lens 104 and a normal K2 perpendicular to the tangent K1 may have a predetermined angle θ1 with the optical axis OA. The maximum tangent angle θ1 of the eighth surface S8 in the first direction X may be 25 degrees or more relative to an axis parallel to the optical axis, for example, in a range of 25 degrees to 60 degrees or in a range of 35 degrees to 50 degrees. The maximum tangent angle of the seventh surface S7 in the first direction X may be 25 degrees or more relative to an axis parallel to the optical axis, for example, in a range of 25 degrees to 60 degrees or in a range of 30 degrees to 45 degrees. With respect to the maximum tangential angle, the maximum tangential angle of the sensor-side sixth surface S6 of the third lens 103 may be the largest among the tangential angles of the lens, and may be, for example, in a range of 40 degrees to 65 degrees. Therefore, light refracted from the third lens 103 and the fourth lens 104 in the optical system 1000 having five or less lenses may be refracted to the entire area of ​​the image sensor 300 .

[0102] 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. CT3 is the center thickness or optical axis thickness of the third lens 103, and ET3 is the edge thickness of the third lens 103. The edge thickness is the distance in the optical axis direction between the object-side surface and the sensor-side surface at the end of the effective area of ​​each lens. CG3 is the optical axis distance (i.e., center distance) from the center of the sensor-side surface of the third lens 103 to the center of the object-side surface of the fourth lens 104. That is, CG3 is the distance from the center of the sixth surface S6 to the center of the seventh surface S7. EG3 is the distance in the optical axis direction (i.e., edge distance) from the edge of the sensor-side surface of the third lens 103 to the edge of the object-side surface of the fourth lens 104.

[0103] The optical system 1000 can guide light to the entire area of ​​the image sensor through a small number of lens optical systems by making the effective diameter of at least one plastic lens having an aspherical surface larger than the effective diameter of a glass lens. The first lens 101 can be disposed on the object side of the aperture stop ST, and the second lens 102, the third lens 103, and the fourth lens 104 can be disposed on the sensor side of the aperture stop ST. Here, the effective diameters of the first lens 101 to the fourth lens 104 are defined as CA1, CA2, CA3, and CA4, and the effective diameters of the object side surface and the sensor side surface of the first lens 101 to the fourth lens 104 can be defined as CA11, CA12, CA21, CA22, CA31, CA32, and CA42. When the aperture stop ST is disposed on the sensor side surface of the first lens 101, the following conditions can be satisfied.

[0104] Condition 1: CA2 <CA1<CA3<CA4

[0105] Condition 2: (CA1-CA2) < (CA3-CA2) < (CA4-CA3)

[0106] Condition 3: CA2 <CA3<ImgH<CA4<(2*ImgH)

[0107] Condition 4: CA21 <CA11<CA32<CA42

[0108] Since the second lens 102 disposed on the sensor side of the aperture stop ST has negative power (F2<0), the second lens 102 can refract incident light in the optical axis direction, and since the third lens 103 has a convex meniscus shape toward the sensor side, it can refract light in the edge direction of the lens. Therefore, the weight yield of the optical system can be prevented from being reduced by the second lens 102 and the third lens 103, and the production efficiency can be improved. Here, the composite focal length of the second lens 102 to the fourth lens 104 disposed on the sensor side of the aperture stop ST can have a positive value, and the TTL within the field of view can be reduced.

[0109] The distance between the second lens 102 and the third lens 103 may gradually decrease from the center to the edge. Due to the concave shape of the sensor-side surface of the second lens 102 and the concave shape of the object-side surface of the third lens 103, the distance may gradually decrease from the optical axis to the edge.

[0110] Figure 3 yes Figure 1 Examples of lens data for an optical system of an embodiment of the present invention. Figure 3As shown, the radius of curvature of the first lens 101 to the fourth lens 104 on the optical axis OA, the center thickness CT of the lens, the center distance CG between adjacent lenses, the refractive index at the d-line, the Abbe number, and the size of the effective radius (e.g., semi-aperture) can be set. When the radius of curvature of each lens on the optical axis is expressed as an absolute value, the radius of curvature of each of the first lens 101 to the fourth lens 104 on the optical axis OA can be 50 mm or less, for example, in the range of 1 mm to 50 mm or 1 mm to 30 mm. In addition, the difference in the radius of curvature of two adjacent lens surfaces can be less than 50 mm, for example, in the range of 0.1 mm to 30 mm or 0.1 mm to 20 mm. Therefore, light can be guided without increasing the difference in the radius of curvature of the optical system 1000 having five or less lenses. For example, the difference in curvature radius between the first surface S1 and the second surface S2 can be 15 mm or less, the difference in curvature radius between the second surface S2 and the third surface S3 can be 6 mm or less, the difference in curvature radius between the third surface S3 and the fourth surface S4 can be 12 mm or less, the difference in curvature radius between the fourth surface S4 and the fifth surface S5 can be 15 mm or less, the difference in curvature radius between the fifth surface S6 and the sixth surface S6 can be 15 mm or less, the difference in curvature radius between the sixth surface S6 and the seventh surface S7 can be 5 mm or less, and the difference in curvature radius between the seventh surface S7 and the eighth surface S8 can be 3 mm or less.

[0111] When the radius of curvature of each lens is expressed as an absolute value, the radius of curvature of the fifth surface S5 of the third lens 103 or the second surface S2 of the first lens 101 may be the largest among the lenses. Preferably, the radius of curvature of the fifth surface S5 of the third lens 103 may be the largest. The radius of curvature of the eighth surface S8 of the fourth lens 104 may be the smallest among the lenses. The maximum radius of curvature may be 50 mm or less, for example, 30 mm or less, and may be less than 50 times, for example, 4 to 10 times, of the minimum radius of curvature. The radius of curvature of the fourth lens 104, which is an aspherical lens, may be smaller than the radius of curvature of the first lens 101 and the second lens 102 made of glass. At this time, the radius of curvature is the average of the absolute values ​​of the radius of curvature of the object side surface and the sensor side surface of each lens.

[0112] When expressed as an absolute value, the radius of curvature on the optical axis of the first lens 101 arranged on the object side of the aperture stop ST may be larger than the radius of curvature of the second lens 102 arranged on the sensor side of the aperture stop ST. When expressed as an absolute value, the radius of curvature on the optical axis of the fourth lens 104 may be smaller than the radius of curvature of the third lens 103. When expressed as an absolute value, the difference in radius of curvature between the object-side surface and the sensor-side surface of the third lens 103 may be larger than the difference in radius of curvature between the object-side surface and the sensor-side surface of the fourth lens 104, and may be larger than the difference in radius of curvature between the object-side surface and the sensor-side surface of the second lens 102.

[0113] When the third lens 103 is designed as an aspherical surface, it can satisfy thermal compensation and improve optical performance, but it may not be as easy to assemble as a spherical lens, and due to the assemblability of the aspherical third lens 103, the aspherical third lens 103 may affect the optical characteristics of the lens set on the sensor side more than the third lens 103. If the third lens is a spherical lens, even if the third lens is affected by the optical characteristics, the curvature radius of the third lens will not change significantly due to the spherical characteristics. The present invention is designed so that the curvature radius of the third lens 103 with an aspherical surface is 30m or less, the effective diameter is small, and the thickness is thick, so that assembly can be easy, and if the thickness is large on the optical axis, even if it is slightly tilted to the optical axis during assembly, the influence on the lens on the sensor side can be minimized.

[0114] In addition, since the first lens 101 having a spherical surface is arranged on the object side of the aperture stop ST and is the lens most sensitive to optical characteristics, the radius of curvature of the first lens 101 is made larger than the radius of curvature of the second lens, and the thickness of the first lens 101 is set thicker than the thickness of the second lens 102. Here, a sensitive lens means a lens that has a large influence on the optical system even if the assembly is slightly misaligned. Therefore, since the lens placed on the object side of the aperture stop is most sensitive to assembly, the radius of curvature of the lens adjacent to the aperture stop or the first lens sensitive to assembly is adjusted. Since the fourth lens 104 is set as an aspherical surface, the radius of curvature on the optical axis can be increased without greatly increasing the difference in the radius of curvature between the object side surface and the sensor side surface, and the assembly performance can be improved by a large effective diameter, and the influence on the optical characteristics can be reduced.

[0115] The radii of curvature of the first surface S1 and the second surface S2 of the first lens 101 are defined as L1R1 and L1R2, the radii of curvature of the seventh surface S7 and the eighth surface S8 of the fourth lens 104 are defined as L4R1 and L4R2, and the radii of curvature of each lens surface of the second lens 102 and the third lens 103 can be defined as L2R1, L2R2, L3R1, and L3R2. The ratio of the radius of curvature of the object side surface to the sensor side surface of each lens is as follows.

[0116] Condition 1: 0 < L1R1 / L1R2 < 1, Condition 2: 1 < L2R1 / L2R2 < 5

[0117] Condition 3: 1.5 < |L3R1 / L3R2| < 6 (where L3R1, L3R2 < 0)

[0118] Condition 4: 0.7 < |L4R1 / L4R2| < 2, Condition 5: 3 mm ≤ |L3R1| - |L3R2| ≤ 30 mm Preferably, Condition 5 is satisfied: 3 mm ≤ |L3R1| - |L3R2| ≤ 15 mm

[0119] Condition 6: 0.1 mm < (L4R1 - L4R2) < 3 mm

[0120] If the difference between the object side radius of curvature and the sensor side radius of curvature of the third lens 103 is set within the above range, the assembly performance of the third lens 103 with an aspherical surface can be improved, and the optical influence of the third lens 103 can be reduced. Additionally, 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 the condition: LiR1 / LiR2 (i = 1 to 4) can be the smallest when i = 1 and the largest when i = 3. Additionally, the difference in the radius of curvature between adjacent aspherical lens surfaces and spherical lens surfaces can satisfy the following condition. Condition 7: 1 < |L3R1| / L2R2 < 6

[0121] The difference in the radius of curvature between the spherical lens surface and the aspherical lens surface is set to 30 mm or less, for example, within the range of 3 mm to 15 mm, so that the chromatic aberration caused by the spherical lens surface can be corrected.

[0122] When the center thicknesses of the first lens 101 to the fourth lens 104 are defined as CT1 to CT4 and the edge thicknesses of the first lens 101 to the fourth lens 104 are defined as ET1 to ET4, the sum of the center thicknesses of the first lens 101 to the fourth lens 104 can be defined as ∑CT, and the sum of the edge thicknesses of the first lens 101 to the fourth lens 104 can be defined as ∑ET.

[0123] Regarding the thickness of the lens, the central thickness CT3 of the third lens 103 can be greater than the central thicknesses CT1, CT2, and CT4 of the first lens 101, the second lens 102, and the fourth lens 104, and preferably, it can have the maximum thickness among the lenses. Since the central thickness CT3 of the third lens 103 is the largest and the radius of curvature of the sensor-side surface is set to be the largest, the light incident through the glass lens can be refracted to the end of the effective area of the last lens with the largest effective diameter. That is, in order to control the optical path caused by the effective diameter difference between the third lens 103 and the fourth lens 104 and the TTL of 10 mm or less, the third lens 103 can have a convex meniscus shape facing the sensor and the maximum central thickness.

[0124] The central thickness CT2 of the second lens 102 can have the minimum thickness within the lens portion 100. The average value of the central thickness of the aspherical lens can be set to be thicker than the average value of the central thickness of the spherical lens, and accordingly, the light incident through the optical system 1000 with 5 or fewer lenses can be guided to the entire area of the image sensor 300. The ratio of the central thickness to the edge thickness of each lens can satisfy the following conditions.

[0125] Condition 1: 1 < CT1 / ET1 < 2, Condition 2: 0.5 < CT2 / ET2 < 1.5

[0126] Condition 3: 1 < CT3 / ET3 < 2.5, Condition 4: 0.5 < CT4 / ET4 < 1.5

[0127] Condition 5: 0.8 < ∑CT / ∑ET < 1.4 or 1 < ∑CT / ∑ET < 1.2

[0128] Condition 6: 0.1 < CT1 / ∑CT < 0.3, Condition 7: 0.3 < CT3 / ∑CT < 0.7

[0129] In the conditions, when CTi / ETi (i = 1 to 4), it can be the largest when i is 3 and the smallest when i is 4. The difference between the central thickness and the edge thickness of each lens can be set to be greater than 0.005 mm and less than 2 mm. By arranging the aspherical lenses in the third lens 103 and the fourth lens 104, the light can be effectively guided without increasing the difference between the central thickness and the edge thickness of each lens. In addition, by setting the difference between the central thickness and the edge thickness of the fourth lens 104 within the range of Condition 4, the difference in the radius of curvature between the object-side surface and the sensor-side surface can be designed not to be large, the assemblability of the aspherical fourth lens 104 can be improved, and the influence on the optical characteristics can be reduced.

[0130] In addition, the difference between the maximum center thickness and the minimum center thickness of the lens can be 2 mm or less, for example, in the range of 0.5 mm to 2 mm or 1 mm to 2 mm. That is, even if the center thickness of the spherical lens is set to be thin, the optical performance can be maintained without degradation, and the thickness of the imaging device module can be made thin. Further, since the difference between the center thickness and the edge thickness of each lens is not made large, even if at least one lens is tilted, the influence on the optical characteristics can be reduced. This can also reduce the influence on the thermal characteristics between the center and the edge of the lens. The maximum center thickness can be greater than the sum of the center thicknesses of two different lenses. For example, the conditions can be satisfied: (CT1 + CT2) < CT3, (CT1 + CT4) < CT3, and (CT2 + CT4) < CT3.

[0131] The center distances between the first lens 101 to the fourth lens 104 can be defined as CG1 to CG3, and the sum of the center distances between the first lens 101 to the fourth lens 104 can be defined as ∑CG.

[0132] The center distance CG2 between the second lens 102 and the third lens 103 is the center distance between a spherical lens and an aspherical lens, and is the largest within the lens unit 100, greater than the center distances between spherical lenses and greater than the center distances between aspherical lenses. The center thickness of each lens and the center distance between adjacent lenses can satisfy the following conditions.

[0133] Condition 1: 1 < CT1 / CG1 < 3, Condition 2: 0 < CT2 / CG2 < 1

[0134] Condition 3: 2 < CT3 / CG3 < 7, Condition 4: 1 < CT4 / CG3 < 4

[0135] Condition 5: (CT1 / CG1) < (CT3 / CG3), Condition 6: 0.1 < CG3 / ∑CG < 0.7

[0136] Condition 7: 2 < CT3 / CG2 < 5

[0137] The maximum center thickness between the lenses is greater than twice the maximum center distance. For example, by setting a range of 2.1 to 4.5 times, an imaging device module applying an aspherical lens to an optical system can be set without increasing the center distance compared to the center thickness of each lens. In Condition 3, since the aspherical third lens 103 is set to a convex meniscus shape facing the sensor, the center distance between the third lens 104 and the fourth lens 105 can be reduced. Here, if the i-th center distance between two adjacent lenses is defined as CGi, and the center thickness of the i-th lens located closer to the object than CGi is defined as CTi, the following conditions can be satisfied. The ratio of CTi / CGi can be maximum when i is 3 and minimum when i is 2. The condition that the value of CTi / CGi is minimum when i is 2 can be achieved by the shapes of the spherical lens and the aspherical lens.

[0138] 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 Condition 1 can be satisfied: 0 < CT1 / TTL < 0.4 can be satisfied. Preferably, Condition 1 can be satisfied: 0.05 ≤ CT1 / TTL ≤ 0.3. Since the first lens 101 is a spherical lens glass material, an optical system can be designed as follows, and this optical system can satisfy the thermal compensation according to temperature changes by the thickness of the first lens 101 satisfying Condition 1. That is to say, Condition 1 can be a characteristic that appears when the first lens 101 is designed as a spherical glass.

[0139] Condition 2: 0 < CT2 / TTL < 0.2, Condition 3: 0.1 < CT3 / TTL < 0.7

[0140] Condition 4: 0 < CT4 / TTL < 0.4, the ratio of CT1 / TTL in Condition 3 can be greater than the values of Conditions 1, 2, and 4, and can be minimum when i is 2 in the ratio of CTi / TTL (i = 1 to 4).

[0141] Regarding the refractive index, the refractive index of the first lens 101 is the largest among the lenses, and preferably, the refractive index of the first lens 101 may be the largest and may be 1.7 or more. The refractive index difference between the first lens 101 and the third lens 103 is 0.20 or more. Since the first lens 101 is the glass lens closest to the object side and is arranged with the largest refractive index, at least one or more lenses arranged on the sensor side of the first lens 101 may be made of a plastic material. Since the first lens 101 is arranged from a glass material having a high refractive index, it may be arranged to be thicker than the center thickness of the second lens 102 arranged on the sensor side of the aperture stop ST and thinner than the third lens 103. Since the first lens 101 is made from a glass material having a high refractive index, the amount of change such as contraction and movement of the lens is small as the ambient temperature changes from room temperature to low temperature / high temperature. Therefore, even in the case of temperature change, the resolution drop is smaller than that of the plastic lens. The fact that the first lens arranged at the front of the optical system is made of a glass material having a high refractive index has the effect of reducing the amount of change in the resolution of the entire optical system as the ambient temperature changes from room temperature to low temperature / high temperature. The first lens 101 is a glass lens closest to the object side, and by designing it to have the highest refractive index, at least one or more of the lenses arranged on the sensor side of the first lens 101 can be made of a plastic material, thereby preventing the resolution from decreasing due to temperature changes. When the refractive index of the first lens 101 is made high, the center thickness of the first lens 101 can be set thin, thereby reducing the weight of the lens, increasing dispersion, and increasing the light reflectivity of the lens facing the driver. The refractive index of the second lens 102 is the lowest among the lenses. The difference between the maximum refractive index and the minimum refractive index can be 0.25 or more. By adjusting the refractive index of the spherical lens and the aspherical lens, the incident light efficiency can be increased, and the incident light can be guided to the image sensor 300.

[0142] When explaining the Abbe number, the Abbe number of the second lens 102 is the largest among the lenses and may be 55 or more. The Abbe number of at least one of the third lens 103 and the fourth lens 104 is the smallest among the lenses. The difference between the maximum Abbe number and the minimum Abbe number may be 30 or more. By making the Abbe number of the object side lens of the aperture stop ST smaller, making the Abbe number of the sensor side lens larger, and setting the Abbe number of the aspherical fourth lens 104 closest to the image sensor 300 to be small, the dispersion of light traveling between the glass lenses can be controlled, and the dispersion between the spherical lens and the aspherical lens can be increased to guide the light to the image sensor 300.

[0143] The focal lengths F1 and F3 of the first lens 101 and the third lens 103 may have positive power, and the focal lengths F2 and F4 of the second lens 102 and the fourth lens 104 may have negative power. In addition, two lenses arranged adjacently may be arranged with opposite signs. Since the lens repeatedly contracts and expands as the temperature changes from low temperature to high temperature, the plastic lens can correct the chromatic aberration of the glass lens. When the focal length is expressed as an absolute value, the focal length of the fourth lens 104 is the largest among the lenses and may be 100 mm or more. The focal length of the first lens 101 is the smallest among the lenses. The difference between the maximum focal length and the minimum focal length may be 100 mm or more. By increasing the focal length difference between the third lens 103 and the fourth lens 104, which are aspherical lenses, the optical system may have improved MTF characteristics, aberration control characteristics, resolution characteristics, etc. within a set field of view, and may have good optical performance at the periphery of the field of view.

[0144] like Figure 4 As shown, in the lens of the lens portion 100 in the first embodiment, the lens surfaces of the third lens 103 and the fourth lens 104 may include an aspheric surface having a 30th order aspheric coefficient. For example, the third lens 103 and the fourth lens 104 may include a lens surface having a 30th order aspheric coefficient. As described above, since the aspheric surface having a 30th order aspheric coefficient (a value other than "0") can significantly change the aspheric shape of the periphery, the optical performance of the periphery of the field of view (FOV) can be well corrected. Figure 5 As shown, the thicknesses T1 to T4 of the first lens 101 to the fourth lens 104 and the distances G1 to G3 between two adjacent lenses may be set. Figure 5 As shown, the thickness T1 to T4 of each lens in the Y-axis direction can be represented at intervals of 0.1 mm or more from the optical axis, and each of the distances G1 to G3 between the lenses can be represented at intervals of 0.1 mm or more from the optical axis.

[0145] like Figure 6 As shown, in Figure 1 In the optical system and camera module, when the center field value of the image sensor is 0 and the diagonal end field of the image sensor is 1, the chief ray angle (CRA) is 10 degrees or more, for example, in the range of 10 degrees to 35 degrees or in the range of 10 degrees to 25 degrees. Fig. 20 As shown, in the optical system according to the first embodiment, the relative illumination or relative illumination from the center of the image sensor to the image height, that is, from 0 to 3.09 mm, is shown, and it can be seen that the relative illumination from the center of the image sensor to the diagonal end is 55% or more, for example, 55% or more. That is, it can be seen that there is almost no difference in the relative illumination difference according to the low temperature, room temperature, and high temperature until 3.09 mm from the optical axis.

[0146] Figures 7 to 9 It is shown Figure 1 Graphs of diffraction MTF at room temperature, low temperature, and high temperature in an optical system of FIG. 1 and FIG. 2 are graphs showing modulation according to spatial frequency. Figures 7 to 9 As shown, in the first embodiment of the present invention, the deviation of the MTF between the low temperature and the high temperature based on the room temperature can be less than 10%, that is, 7% or less. Figures 7 to 9 , the x-axis represents the defocus position, and the y-axis represents the MTF, and the graph is measured from 0.000 mm to 3.092 mm from F1 to F11 in units of 0.309 mm. Figures 10 to 12 It is shown Figure 1 Curve diagram of aberration characteristics in an optical system at room temperature, low temperature, and high temperature. Figures 10 to 12 The aberration curve diagram is a curve diagram measuring spherical aberration (longitudinal spherical aberration), astigmatism field curve and distortion from left to right. Figures 10 to 12 In , the X-axis may represent focal length (mm) and distortion (%), and the Y-axis may mean the height of the image. In addition, the graph of spherical aberration is a graph for light in wavelength bands of about 920 nm, about 940 nm, and about 960 nm, and the graphs of astigmatism and distortion are graphs for light in a wavelength band of about 940 nm. Figures 10 to 12 In the aberration diagram, it can be interpreted that the closer each curve at room temperature, low temperature, and high temperature is to the Y-axis, the better the aberration correction function is. It can be seen that the optical system 1000 according to the first embodiment has a measurement value close to the Y-axis in almost all areas. That is, the optical system 1000 according to the first embodiment has improved resolution and can have good optical performance not only in the center of the FOV but also in the periphery. Here, the low temperature is -20 degrees or lower, for example, in the range of -20 degrees to -40 degrees, the room temperature is in the range of 22 degrees ±5 degrees or in the range of 18 degrees to 27 degrees, and the high temperature can be in the range of 85 degrees or higher, for example, in the range of 85 degrees to 105 degrees. Therefore, it can be seen that Figures 10 to 12 The reduction in brightness modulation from low temperature to high temperature is less than 10%, such as less than 5%, or is almost unchanged.

[0147] When the central wavelength of the infrared wavelength is 940nm±20nm, and the distance from the first lens of the camera module to the subject is 600mm as a standard, 400mm<depth of field<1000mm, when 800mm is a standard, 500mm<depth of field<1400mm, and when 1100mm is a standard, 700mm<depth of field<2500mm. The optical system of the first embodiment disclosed above can effectively control aberration characteristics such as chromatic aberration and distortion aberration, and can have good optical performance not only in the center of FOV but also in the periphery.

[0148] Will refer to Figures 13 to 19 An optical system and a camera module according to a second embodiment of the present invention are described. In describing the second embodiment, configurations different from the first embodiment will be described, and the same configurations will refer to the first embodiment.

[0149] Reference Fig.13 and Fig.14 , the optical system 1000 according to the second embodiment includes a lens part 100A, and the lens part 100A may include first to fourth lenses 111 to 114. The first lens 111 may be a first lens group LG1, and the second to fourth lenses 112, 113, and 114 may be a second lens group LG2.

[0150] The first lens 111 may have a positive (+) optical power on the optical axis OA. The first lens 111 may be made of glass. On the optical axis, the first surface S1 of the first lens 111 may have a convex shape, and the second surface S2 may have a concave shape. The second lens 112 may have a negative (-) optical power on the optical axis OA. The second lens 112 may be made of glass. On the optical axis OA, the third surface S3 of the second lens 112 may have a convex shape, and the fourth surface S4 may be concave. The first lens 111 and the second lens 112 may be set as spherical lenses made of glass.

[0151] The third lens 113 may have positive (+) or negative (-) optical power on the optical axis OA. The third lens 113 may have positive (+) optical power. The third lens 113 may be made of a plastic material. On the optical axis, the fifth surface S5 of the third lens 113 may have a concave shape, and the sixth surface S6 on the sensor side may have a convex shape. The fifth surface S5 and the sixth surface S6 may be aspherical. The center thickness of the third lens 113 may be the thickest among the lenses. The edge thickness of the third lens 113 may be the thickest among the lenses. Since the third lens 113 has the thickest thickness and has a meniscus shape convex toward the sensor side on the optical axis, the effective diameter of the fourth lens 114 may be increased.

[0152] The fourth lens 114 may have negative power on the optical axis OA. The fourth lens 114 may include a plastic material. On the optical axis, the seventh surface S7 of the fourth lens 114 may have a convex shape, and the eighth surface S8 may have a concave shape. The fourth lens 114 may be configured as an aspherical lens made of a plastic material. The seventh surface S7 and the eighth surface S8 may be aspherical on the optical axis.

[0153] The fourth lens 114 may be an aspheric lens closest to the image sensor 300. Since the aspheric lens is arranged closest to the image sensor 300, it is possible to prevent degradation of optical performance, improve aberration characteristics, and control the impact on resolution. In addition, by arranging the aspheric lens as the lens closest to the image sensor 300, the aspheric lens may be insensitive to assembly tolerances compared to a spherical lens. In other words, being insensitive to assembly tolerances means that even if it is assembled slightly differently from the design during assembly, the optical performance may not be significantly affected. Therefore, the effective diameter of the fourth lens 114 may be increased or the center thickness or edge thickness may be increased. In other words, the effective diameter of the fourth lens 114 may have the largest effective diameter among the effective diameters of the lens. The center thickness or edge thickness of the fourth lens 114 may be greater than the center thickness or edge thickness of the glass lens.

[0154] The seventh surface S7 of the fourth lens 114 may have a first critical point P1 (see Figure 2 ). The sensor-side eighth surface S8 of the fourth lens 114 may have a second critical point P2 from the optical axis OA to the end of the effective area (see Figure 2 ). The first critical point P1 of the seventh surface S7 on the object side may be located at a distance of 1.9 mm or less in a direction perpendicular to the optical axis, for example, between a point of 1.2 mm and a point of 1.9 mm. Since the first critical point P1 is set closer to the optical axis than the second critical point P2, light incident through the seventh surface S7 may be refracted to the periphery of the eighth surface S8. The second critical point P2 of the eighth surface S8 on the sensor side may be located at a distance of 1.7 mm or more in a direction perpendicular to the optical axis, for example, between a point of 1.7 mm and a point of 2.3 mm. For example, on the seventh and eighth surfaces, the Sag value increases to the first and second critical points in a direction perpendicular to the optical axis, and then decreases toward the edge after the first and second critical points. The eighth surface S8 of the fourth lens 114 may refract light to the periphery of the image sensor 300 through the second critical point P2. When expressed as an absolute value of the Sag value, the maximum value of Sag32 may be greater than the maximum values ​​of Sag31, Sag41, and Sag42. Sag32 is the optical axis distance between the object side surface of the third lens 113 and a straight line perpendicular to the center of the sensor side surface of the third lens 113, Sag42 is the optical axis distance between the sensor side surface of the fourth lens 114 and a straight line perpendicular to the center of the sensor side surface, and Sag41 is the optical axis distance between the object side surface of the fourth lens 114 and a straight line perpendicular to the center of the object side surface.

[0155] A tangent line K1 (see FIG. 1 ) passing through any point of the eighth surface S8 of the fourth lens 114 Figure 2) and a normal line K2 perpendicular to the tangent line K1 (see Figure 2 ) may have a predetermined angle θ1 with respect to the optical axis OA (see Figure 2 ). The maximum tangential angle θ1 of the eighth surface S8 in the first direction X may be 25 degrees or more based on an axis parallel to the optical axis, for example, in the range of 25 degrees to 60 degrees or in the range of 25 degrees to 45 degrees. The maximum tangential angle of the thirteenth surface S13 in the first direction X may be 35 degrees or less based on an axis parallel to the optical axis, for example, in the range of 5 degrees to 35 degrees or in the range of 7 degrees to 27 degrees. Regarding the maximum tangential angle, the maximum tangential angle of the sixth surface S6 on the sensor side of the third lens 113 may be the largest among the tangential angles of the lenses, and may be, for example, in the range of 33 degrees to 65 degrees. Therefore, the light refracted by the third lens 113 and the fourth lens 114 in the optical system 1000 having five or fewer lenses can be refracted to the entire area of the image sensor 300.

[0156] The optical system 1000 can guide light to the entire area of the image sensor through a small number of lens optical systems by making the effective diameter of at least one plastic lens having an aspherical surface larger than the effective diameter of the glass lens. The aperture stop ST may be provided around the sensor side of the first lens 111. The first lens 111 may be arranged on the object side of the aperture stop, and the second lens 112, the third lens 113, and the fourth lens 114 may be arranged on the sensor side of the aperture stop ST, and the following conditions may be satisfied.

[0157] Condition 1: CA2 < CA1 < CA3 < CA4, Condition 2: (CA1 - CA2) < (CA3 - CA2) < (CA4 - CA3)

[0158] Condition 3: CA2 < CA3 < ImgH < (2 * ImgH) < CA4, Condition 4: CA21 < CA11 < CA32 < CA42

[0159] Since the second lens 112 disposed on the sensor side of the aperture stop ST has a negative optical power (F2<0), the second lens 112 can refract the incident light in the optical axis direction, and since the third lens 113 has a convex meniscus shape toward the sensor side, it can refract the light in the edge direction of the lens. Therefore, the weight yield of the optical system can be prevented from decreasing by the second lens 112 and the third lens 113, and the production efficiency can be improved. Here, the composite focal length of the second lens 112 to the fourth lens 114 disposed on the sensor side of the aperture stop ST can have a positive value, and the TTL within the field of view can be reduced. The distance between the second lens 112 and the third lens 113 can gradually decrease from the center to the edge. Due to the concave shape of the sensor-side surface of the second lens 112 and the concave shape of the object-side surface of the third lens 113, the distance can gradually decrease from the optical axis to the edge.

[0160] Fig.14 yes Fig.13 Examples of lens data for an optical system of an embodiment of the present invention. Fig.14 As shown, the radius of curvature of the optical axis OA of the first lens 111 to the fourth lens 114, the center thickness CT of the lens, the center distance CG between adjacent lenses, the refractive index at the d-line, the Abbe number, and the size of the effective radius (e.g., semi-aperture) can be set. When the radius of curvature of each lens on the optical axis is expressed as an absolute value, the radius of curvature of each of the first lens 111 to the fourth lens 114 on 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 25 mm. In addition, the difference in the radius of curvature of two 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 10 mm. Therefore, light can be guided without increasing the difference in the radius of curvature of the optical system 1000 having 5 or less lenses. For example, the difference in curvature radius between the first surface S1 and the second surface S2 may be 10 mm or less, the difference in curvature radius between the second surface S2 and the third surface S3 may be 10 mm or less, the difference in curvature radius between the third surface S3 and the fourth surface S4 may be 5 mm or less, the difference in curvature radius between the fourth surface S4 and the fifth surface S5 may be 5 mm or less, the difference in curvature radius between the fifth surface S5 and the sixth surface S6 may be 5 mm or less, the difference in curvature radius between the sixth surface S6 and the seventh surface S7 may be 7 mm or less, and the difference in curvature radius between the seventh surface S7 and the eighth surface S8 may be 3 mm or less.

[0161] When the radius of curvature of each lens on the optical axis is expressed as an absolute value, the radius of curvature of the fifth surface S5 of the third lens 113 or the second surface S2 of the first lens 111 can be the largest among the lenses. Preferably, the radius of curvature of the second surface S2 of the first lens 111 can be the largest. The radius of curvature of the eighth surface S8 of the fourth lens 114 can be the smallest among the lenses. The maximum radius of curvature can be 30 mm or less, for example, 25 mm or less, and can be less than 20 times the minimum radius of curvature, for example, in the range of 2 to 10 times. The radius of curvature of the aspherical fourth lens 114 can be less than the radius of curvature of the first lens 111 and the second lens 112 made of glass. At this time, the radius of curvature is the average value of the absolute values of the radius of curvature of the object-side surface and the sensor-side surface of each lens.

[0162] When expressed as an absolute value, the radius of curvature of the first lens 111 disposed on the object side of the aperture stop ST on the optical axis can be greater than the radius of curvature of the second lens 112 disposed on the sensor side of the aperture stop ST. When expressed as an absolute value, the radius of curvature of the fourth lens 114 on the optical axis can be less than the radius of curvature of the third lens 113. When expressed as an absolute value, the difference in the radius of curvature between the object-side surface and the sensor-side surface of the third lens 113 can be greater than the difference in the radius of curvature between the object-side surface and the sensor-side surface of the fourth lens 114, and can be less than the difference in the radius of curvature between the object-side surface and the sensor-side surface of the first lens 112.

[0163] The radius of curvature of the aspherical third lens 113 is 25 m or less, and the effective diameter can be designed to be small and thick, and the radius of curvature of the first lens 111 having a spherical surface can be designed to be large. In addition, since the third lens 113 and the fourth lens 114 are provided with aspherical surfaces, the radius of curvature on the optical axis can be increased without increasing the radius of curvature, and the difference in the radius of curvature between the object-side surface and the sensor-side surface can be made smaller. Furthermore, the assembly can be improved by a large effective diameter, and the influence on the optical characteristics can be reduced.

[0164] The ratio of the radius of curvature of the object-side surface and the sensor-side surface of each lens is as follows.

[0165] Condition 1: 0 < L1R1 / L1R2 < 1, Condition 2: 1 < L2R1 / L2R2 < 3

[0166] Condition 3: 1 < |L3R1 / L3R2| < 2 (however, L3R1, L3R2 < 0)

[0167] Condition 4: 0.5 < |L4R1 / L4R2| < 2, Condition 5: 2 mm < (L1R2 - L1R1) ≤ 10 mm. Preferably, Condition 5 is satisfied: 4 mm ≤ (L1R2 - L1R1) ≤ 8 mm

[0168] Condition 6: 1 mm < (L3R1 - |L3R2|) < 4 mm

[0169] When the difference between the object-side curvature radius and the sensor-side curvature radius of the third lens 113 is set within the above range, the assembly performance of the third lens 113 with an aspherical surface can be improved, and the optical influence caused by the third lens 113 can be reduced. In addition, if the absolute value of the curvature radius of the object-side surface of the i-th lens is LiR1, and the absolute value of the curvature radius of the sensor-side surface is LiR2, the value of LiR1 / LiR2 (i = 1 to 4) can be the smallest when i = 1 and the largest when i = 2.

[0170] In addition, the difference in curvature radius between adjacent aspherical lens surfaces and spherical lens surfaces can satisfy the following Condition 7: 1 < |L3R1| / L2R2 < 4. The maximum difference in curvature radius between the spherical lens surface and the aspherical lens surface is set to 30 mm or less, for example, within the range of 3 mm to 15 mm, so that the chromatic aberration caused by the spherical lens surface can be corrected.

[0171] When explaining the thickness of the lens, the central thickness CT3 of the third lens 113 can be greater than the central thicknesses CT1, CT2, and CT4 of the first lens 111, the second lens 112, and the fourth lens 114, and can have the maximum thickness within the lens portion 100A. The central thickness CT2 of the second lens 112 can have the minimum thickness within the lens portion 100A. The average value of the central thickness of the aspherical lens can be set to be thicker than the average value of the central thickness of the spherical lens, and accordingly, the light incident through the optical system 1000 with 5 or fewer lenses can be guided to the entire area of the image sensor 300. The ratio of the central thickness to the edge thickness of each lens can satisfy the following conditions.

[0172] Condition 1: 1 < CT1 / ET1 < 3, Condition 2: 0.5 < CT2 / ET2 < 1.5

[0173] Condition 3: 1 < CT3 / ET3 < 3, Condition 4: 0.5 < CT4 / ET4 < 2.5

[0174] Condition 5: 1 < ∑CT / ∑ET < 2 or 1 < ∑CT / ∑ET < 1.6

[0175] Condition 6: 0.1 < CT1 / ∑CT < 0.3, Condition 7: 0.3 < CT3 / ∑CT < 0.7

[0176] In the conditions, when CTi / ETi (i = 1 to 4), it can be maximum when i = 3 and minimum when i = 2. The difference between the center thickness and the edge thickness of each lens can be set to be greater than 0.005 mm and less than 2 mm. By arranging aspherical lenses in the third lens 113 and the fourth lens 114, light can be effectively guided without increasing the difference between the center thickness and the edge thickness of each lens. Additionally, by setting the difference between the center thickness and the edge thickness of the fourth lens 114 within the range of Condition 4, the difference in the radius of curvature between the object side surface and the sensor side surface can be designed to be small, the assemblability of the aspherical fourth lens 114 can be improved, and the influence on the optical characteristics can be reduced.

[0177] Moreover, the difference between the maximum center thickness and the minimum center thickness of the lens can be 2 mm or less, for example, within the range of 0.5 mm to 2 mm or 1 mm to 2 mm. That is, even if the center thickness of the spherical lens is set thin, the optical performance can be not reduced, and the thickness of the imaging device module can be set thin. Additionally, since the difference between the center thickness and the edge thickness of each lens is not made large, even if at least one lens is tilted, the influence on the optical characteristics can be reduced. This can also reduce the influence on the thermal characteristics between the center and the edge of the lens. Furthermore, the maximum center thickness of the lens can be greater than the sum of the center thicknesses of two different lenses. For example, the following conditions can be satisfied: (CT1 + CT2) < CT3, (CT1 + CT4) < CT3, and (CT2 + CT4) < CT3.

[0178] The center distance CG2 between the second lens 112 and the third lens 113 is the center distance between a spherical lens and an aspherical lens, which is the largest within the lens portion 100A, greater than the center distance between spherical lenses, and greater than the center distance between aspherical lenses. The center thickness of each lens and the center distance between adjacent lenses can satisfy the following conditions.

[0179] Condition 1: 1 < CT1 / CG1 < 3, Condition 2: 0 < CT2 / CG2 < 1

[0180] Condition 3: 2 < CT3 / CG3 < 7, Condition 4: 1 < CT4 / CG3 < 4

[0181] Condition 5: (CT1 / CG1) < (CT3 / CG3), Condition 6: 0.1 < CG3 / ∑CG < 0.7

[0182] Condition 7: 1 < CT3 / CG2 < 4

[0183] The maximum central thickness between the lenses is greater than twice the maximum central distance. For example, by setting a range of 2.1 times to 3.5 times, an imaging device module applying an aspherical lens to an optical system can be set without increasing the central distance compared to the central thickness of each lens. In Condition 3, since the aspherical third lens 113 is set to a convex meniscus shape facing the sensor, the central distance between the third lens 113 and the fourth lens 114 can be reduced. Here, if the i-th central distance between two adjacent lenses is defined as CGi, and the central thickness of the i-th lens located closer to the object than CGi is defined as CTi, the following conditions can be satisfied. The ratio of CTi / CGi can be maximum when i is 3 and minimum when i is 2. The condition that the value of CTi / CGi is minimum when i is 2 can be achieved by the shapes of the spherical lens and the aspherical lens.

[0184] The relationship between the central thickness of each lens and the TTL can satisfy the following conditions.

[0185] Condition 1: 0 < CT1 / TTL < 0.4, Condition 2: 0 < CT2 / TTL < 0.2

[0186] Condition 3: 0.1 < CT3 / TTL < 0.7, Condition 4: 0 < CT4 / TTL < 0.4

[0187] The ratio of CT1 / TTL in Condition 3 can be greater than the values in Conditions 1, 2, and 4, and can be minimum when i is 2 among the ratios of CTi / TTL (i = 1 to 4).

[0188] Regarding the refractive index, the refractive index of the first lens 111 can be the maximum among the lenses, and preferably, the refractive index of the first lens 111 can be the maximum and can be 1.7 or greater. The refractive index difference between the first lens 111 and the third lens 113 can be 0.20 or greater. The refractive index of the second lens 112 can be the minimum among the lenses. The difference between the maximum refractive index and the minimum refractive index can be 0.25 or greater. By controlling the refractive indices of the spherical lens and the aspherical lens, the incident efficiency can be increased, and the incident light can be guided to the image sensor 300.

[0189] Regarding the Abbe number, the Abbe number of the second lens 112 is the largest among the lenses and may be 55 or more. The Abbe number of at least one of the third lens 113 and the fourth lens 114 is the smallest among the lenses. The difference between the maximum Abbe number and the minimum Abbe number may be 30 or more. By reducing the Abbe number of the object side lens of the aperture stop ST, increasing the Abbe number of the sensor side lens, and setting a small Abbe number of the aspherical fourth lens 114 closest to the image sensor 300, the dispersion of light traveling between the glass lenses can be controlled, and the dispersion between the spherical lens and the aspherical lens can be increased to guide the light to the image sensor 300.

[0190] The focal lengths F1 and F3 of the first lens 111 and the third lens 113 may have positive power, and the focal lengths F2 and F4 of the second lens 112 and the fourth lens 114 may have negative power. In addition, two lenses arranged adjacently may be arranged with opposite signs. Since the lens repeatedly contracts and expands as the temperature changes from low temperature to high temperature, the plastic lens can correct the chromatic aberration of the glass lens. When the focal length is expressed as an absolute value, the focal length of the third lens 113 is the largest among the lenses and may be greater than 18. The focal length of the first lens 111 is the smallest among the lenses. The difference between the maximum focal length and the minimum focal length may be 15 or more. By increasing the focal length difference between the first lens 111 and the second lens 112 as aspherical lenses, the optical system may have improved MTF characteristics, aberration control characteristics, resolution characteristics, etc. within a set field of view, and may have good optical performance at the periphery of the field of view.

[0191] like Fig.15 As shown, in the lens of the lens portion 100A in the embodiment, the aspheric coefficients of the lens surfaces S5 to S8 of the third lens 113 and the fourth lens 114 may be set to Fig.15 The third lens 113 and the fourth lens 114 may include lens surfaces having a 30th order aspheric coefficient. Fig.16 As shown, the thicknesses T1 to T4 of the first lens 111 to the fourth lens 114 and the distances G1 to G3 between two adjacent lenses may be set. Figure 5 As shown, the thickness T1 to T4 of each lens in the Y-axis direction can be represented at intervals of 0.1 mm or more from the optical axis, and the distances G1 to G3 between each lens can be represented at intervals of 0.1 mm or more from the optical axis.

[0192] like Fig.17 As shown, in Fig.13In the optical system and camera module, when the center field value of the image sensor is 0 and the diagonal end field of the image sensor is 1, the CRA (chief ray angle) at the end of the image sensor is 10 degrees or more, for example, in the range of 10 degrees to 35 degrees or in the range of 10 degrees to 25 degrees. Fig. 20 As shown, in the optical system according to the second embodiment, the ambient light ratio or ambient illuminance from the center of the image sensor to the image height, that is, from 0 to 3.09 mm, is shown, and it can be seen that the ambient light ratio from the center of the image sensor to the diagonal end is 55% or more, for example, 55% or more. That is, it can be seen that the ambient illuminance difference according to the low temperature, room temperature, and high temperature is almost the same up to 3.09 mm from the optical axis.

[0193] Fig.18 It is shown Fig.13 Graph of diffraction MTF at room temperature in an optical system of FIG. 1 and graph showing modulation according to spatial frequency. Fig.18 As shown, in the second embodiment of the present invention, the deviation of the MTF between the low temperature and the high temperature based on the room temperature can be less than 10%, that is, 7% or less. Fig.18 , the x-axis represents the defocus position, and the y-axis represents the MTF, and the graph is measured from 0.000 mm to 3.092 mm from F1 to F11 in units of 0.309 mm. Fig.19 It is shown Fig.13 A graph showing the aberration characteristics of an optical system at room temperature. Fig.19 The aberration curve diagram is a curve diagram measuring spherical aberration (longitudinal spherical aberration), astigmatism field curve and distortion from left to right. Fig.19 In , the X-axis may represent focal length (mm) and distortion (%), and the Y-axis may mean the height of the image. In addition, the graph of spherical aberration is a graph for light in wavelength bands of about 920 nm, about 940 nm, and about 960 nm, and the graphs of astigmatism and distortion are graphs for light in a wavelength band of about 940 nm. Fig.19 In the aberration diagram of , the closer each curve at room temperature is to the Y axis, the better the aberration correction function can be explained, and it can be seen that the optical system 1000 according to the second embodiment has a measurement value close to the Y axis in almost all regions. That is, the optical system 1000 according to the second embodiment has improved resolution and can have good optical performance not only at the center of the FOV but also at the periphery.

[0194] The optical system 1000 according to the first embodiment and the second embodiment may satisfy at least one or two or more of the mathematical formulas described below. Accordingly, the optical system 1000 according to the embodiment has improved optical characteristics, can effectively control aberration characteristics such as chromatic aberration and distortion aberration, and can have good optical performance at the center and periphery of the FOV. In addition, the optical system 1000 may have improved resolution. In addition, the thickness of the lens on the optical axis OA described in the formula and the interval between adjacent lenses on the optical axis OA may be referred to the above embodiments.

[0195] [Equation 1] 1 < CT1 / CT2 < 5

[0196] Equation 1 can improve the chromatic aberration of the optical system by setting the difference in the center thicknesses of the first lens and the second lens to be large. Preferably, 1.4 < CT1 / CT2 < 2.2 can be satisfied. The center thicknesses of the first lens 101 and the second lens 102 having spherical surfaces can be set such that the optical performance at the center and periphery of the FOV can be improved.

[0197] [Equation 2] (CT4 * CA4) < (CT3 * CA3)

[0198] CA1 is the effective diameter of the first lenses 101 and 111, and CA3 is the effective diameter of the third lens. The effective diameter is the average of the effective diameters of the object-side surface and the sensor-side surface of each lens. Preferably, the following condition can be satisfied: CA3 < CA4. By setting the thicknesses and the effective diameters of the third and fourth lenses, the optical system can improve spherical aberration.

[0199] [Equation 3] Po1 > 0

[0200] In Equation 3, Po1 means the optical power of the first lenses 101 and 111, and for the performance of the optical system, it can be set to have an effective focal length F similar to the TTL in the optical system. Accordingly, TTL < F can be satisfied, and for example, the following condition can be satisfied: 0.5 < TTL / F < 1.

[0201] [Equation 4] 1.7 ≤ Nd1 < 2.2

[0202] Nd1 is the refractive index at the d-line of the first lens 101 and 111. Formula 4 sets the refractive index of the first lens high so that it can control the factors affecting the reduction of the third-order aberration (Seidel aberration) of the optical system, and can reduce the aberration that may occur when the TTL is slightly long. Formula 4 preferably satisfies: 1.8≤Nd3≤2.1. If it is designed to be lower than the lower limit of Formula 4, the aberration may be reduced to obtain performance, and the optical power of the first lens 101 is weakened, so that light cannot be effectively collected, which may deteriorate the performance of the optical system. If it is designed to be higher than the upper limit of Formula 4, there is a disadvantage that it is difficult to obtain materials. In addition, if the refractive index of the third lens is designed to be lower than the lower limit of Formula 4, in order to increase the optical power of the second lens, the radius of curvature of the second lens must be increased. In this case, lens manufacturing becomes more difficult, the lens defect rate increases, and the yield rate may be reduced.

[0203] [Formula 4-1] 1.65 ≤ Aver (Nd1: Nd4) ≤ 1.75

[0204] In Formula 4-1, Aver(Nd1:Nd4) is an average value of the refractive index values ​​of the d-line of the first to fourth lenses. If the optical system 1000 according to the embodiment satisfies Formula 4-1, the optical system can set the resolution and suppress the influence on TTL.

[0205] [Formula 5] 40 <FOV_H<60

[0206] In Formula 5, FOV_H represents the horizontal field of view and can set the range of the vehicle optical system. The horizontal field of view can be set in an optical system having at least one glass lens and at least one plastic lens and having 5 or less lenses. Formula 5 preferably satisfies: 45≤FOV_H≤55, or a range of 50 degrees ±3 degrees, and at this time, the sensor length in the horizontal direction can be based on 4.80mm±0.5mm. In addition, when Formula 5 is satisfied, when the temperature changes from room temperature to high temperature, the rate of change of the effective focal length and the rate of change of the field of view can be set to 5% or less, for example, 0 to 5%. In addition, even when aspherical lenses and spherical lenses are mixed and used in the optical system 1000, degradation of optical characteristics can be prevented by temperature compensation of the glass lens.

[0207] [Equation 6] L1R1>0

[0208] L1R1 means the radius of curvature of the first surface S1 of the first lens 101 and 111, and can be set to be greater than 0. If this formula 6 is satisfied, the shape of the optical system can be limited. The object side surface of the first lens 101 and 111 has a convex shape from the optical axis toward the driver, and the amount of incident light can be increased. In addition, since the following condition is satisfied: L1R1*L1R2>0, the incident light can be refracted in a direction closer to the optical axis. Therefore, the embodiment can reduce the center distance between the first lens and the second lens, or set the effective diameter of the second lens to be smaller than the effective diameter of the first lens.

[0209] [Formula 6-1] L3R1<0 and L3R1<0

[0210] Since the first lens and the second lens have a meniscus shape convex toward the object side, and the third lens has a meniscus shape convex toward the sensor side, the incident light can be refracted into the effective area of ​​the fourth lens having the largest effective diameter. Since the first lens has a meniscus shape convex toward the object side, the effective diameter of the lens can be designed to gradually increase from the aperture stop position toward the sensor, and the number of lenses can be reduced. In addition, since the following conditions are satisfied: L1R2>L1R1 and |L3R1|>|L3R2|, the effective diameter of the second lens can be designed to be minimum, and TTL can be reduced. If the following conditions are satisfied: |L3R1|<|L3R2|, there is a problem of increased TTL. By setting the radius of curvature of the third lens and the fourth lens to be large, the influence of optical characteristics on the incident light can be reduced.

[0211] [Formula 7]1 <BFL / L4S2_max_sag to Sensor<6

[0212] The BFL is the optical axis distance from the center of the sensor side surface of the last lens, i.e., the fourth lens, to the surface of the image sensor. The L4S2_max_sag to Sensor can be the maximum Sag value of the fourth lenses 104 and 114, i.e., the distance from the low point to the image sensor 300 in the optical axis direction. When the optical system satisfies Equation 7, the TTL can be reduced, and the conditions for manufacturing the imaging device module can be set. In addition, the L4S2_max_sag to Sensor can set the space where the optical filter 500 and the cover glass 400 located between the image sensor 300 and the fourth lenses 104 and 114 can be placed. If the range of Equation 7 is less than the lower limit, the space for arranging circuit structures such as the optical filter and the image sensor becomes limited, and the process of assembling circuit structures such as the filter and the image sensor into the optical system becomes difficult. If the range of Equation 7 is greater than the upper limit, the process of assembling circuit structures such as the filter and the image sensor into the optical system is easy, but the TTL becomes longer, making it difficult to miniaturize the optical system. That is, Equation 7 can set the minimum distance between the image sensor 300 and the last lens, and preferably, it can satisfy the following condition: L7S2_max_sag to Sensor < BFL. In addition, if the last lens does not have a point that protrudes more toward the image sensor than the center of the sensor side surface, the value of Equation 6 can be equal to the BFL. Preferably, if the following condition is satisfied: 2 ≤ BFL / L7S2_max_sag to Sensor ≤ 5, the manufacturing convenience and the reduction of the TTL are easier.

[0213] [Equation 8] 0 < CT1 / CT4 < 1.5

[0214] If Equation 8 is satisfied, the aberration characteristics can be improved, and the influence on the reduction of the optical system can be set. Equation 8 can preferably be satisfied: 0.5 < CT1 / CT4 < 1.3. Equation 8 can set the center thicknesses of the first lens on the object side of the optical system and the fourth lens having an aspherical surface, and can limit the difference in their center thicknesses. Therefore, the chromatic aberration of the optical system can be improved, good optical performance can be achieved at the set field of view, and the TTL can be controlled.

[0215] [Equation 8-1] 0.1 < CT1 / CA11 < 0.5

[0216] In Equation 8-1, the center thickness CT1 of the first lenses 101 and 111 and the effective diameter CA11 of the object-side surface S1 of the first lenses 101 and 111 can be set, and if these are satisfied, deterioration of the strength and optical characteristics of the glass lenses can be prevented. If it is below the range of Equation 8-1, the lens may be damaged or injection molding may be difficult, and if it is greater than the above range, the TTL may increase and the weight of the optical system may become heavy. Preferably, 0.15 < CT1 / CA11 < 0.4 can be satisfied.

[0217] [Equation 9] 1 < (CT3 / CT4) < (CT3 / CT2) < 7

[0218] When the optical system satisfies Equation 9, the ratio of the center thicknesses of adjacent plastic lenses and the ratio of the center thicknesses of adjacent plastic lenses and glass lenses can be set, and the aberration characteristics can be improved, and the influence on the reduction of the optical system can be set. Equation 9 preferably satisfies: 1 < (CT3 / CT4) < (CT3 / CT2) < 3.

[0219] [Equation 10] 1 < CT3 / (CT1 + CT4) < 2

[0220] In Equation 10, the center thickness of the third lenses 103 and 113 made of plastic material can be set to be greater than the sum of the center thicknesses of the first lens and the fourth lens, so that light can be guided to the entire area of the fourth lens.

[0221] [Equation 11] 1 < CT34 / CT4 < 5

[0222] CT34 is the sum of the center thicknesses of the third lens and the fourth lens. If Equation 11 is satisfied, the center thickness of the fourth lenses 104 and 114 made of plastic material is set to be thinner than the center thickness of the third lens, so that the fourth lens can guide the light refracted by the third lens to the periphery of the image sensor 300. Preferably, 2 < CT34 / CT4 < 4 can be satisfied.

[0223] [Equation 12] 0 < CA11 / CA31 < 2

[0224] CA11 means the effective diameter of the first surface S1 of the first lenses 101 and 111, and CA31 means the effective diameter of the fifth surface S5 of the third lenses 103 and 113. If Equation 13 is satisfied, the optical system 1000 can control the incident light and set the factors affecting aberration, and preferably, 1 < CA11 / CA31 < 1.5 can be satisfied. Since the first lens and the third lens satisfy Equation 13, the difference in the effective diameters of the first lens and the third lens is not large, so that the influence of assembly can be reduced, and the optical influence of temperature change can be reduced.

[0225] [Equation 13] 1 < CA42 / CA31 < 3

[0226] CA42 refers to the effective diameter of the eighth surface S8 of the fourth lenses 104 and 114, and CA31 refers to the effective diameter of the fifth surface S5 of the third lenses 103 and 113. When Equation 13 is satisfied, the optical system 1000 can control the incident light path and can set factors for performance variation according to CRA and temperature. Preferably, Equation 13 can be satisfied: 1.5 < CA42 / CA31 < 2.5.

[0227] [Equation 14] 0 < CA22 / CA31 < 2

[0228] CA22 refers to the effective diameter of the fourth surface S4 of the second lenses 102 and 112, and CA31 refers to the effective diameter of the fifth surface S5 of the third lenses 103 and 113. When the optical system 1000 according to the embodiment satisfies Equation 14, the light passing through from the first lens group LG1 to the second lens group LG2 can be controlled, and factors affecting the reduction of lens sensitivity can be set. Equation 15 is preferably satisfied: 0.5 < CA22 / CA31 < 1. Since the second lens and the third lens satisfy Equation 14, the dimensions for assembling the spherical lens and the aspherical lens can be set.

[0229] [Equation 15] 1.5 < ΣPL_CT / ΣGL_CT < 4

[0230] ΣPL_CT is the sum of the center thicknesses of the plastic lenses, for example, the sum of the center thicknesses of the third lens and the fourth lens. ΣGL_CT is the sum of the center thicknesses of the spherical lenses, for example, the sum of the center thicknesses of the first lens and the second lens. If Equation 15 is satisfied, the relationship between the thickness of the aspherical lens and the thickness of the spherical lens with respect to TTL can be set to control the total TTL. Preferably, Equation 15 in the embodiment can be satisfied: 1.7 < ΣPL_CT / ΣGL_CT < 3.

[0231] [Equation 16] 0.3 < ΣPL_CT / TD < 0.7

[0232] 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 fourth lens. Equation 16 can set the relationship between the sum of the center thicknesses of the plastic lenses of the optical system and the maximum distance between the lenses. Equation 16 can preferably be satisfied: 0.4 ≤ ΣPL_CT / TD ≤ 0.6.

[0233] [Equation 17] 0.1 < ΣGL_CT / TD < 0.3

[0234] Equation 17 can set the relationship between the sum of the center thicknesses of the glass lenses of the optical system and the maximum distance between the lenses. Preferably, it can satisfy: 0.15 ≤ ΣGL_CT / TD ≤ 0.25.

[0235] [Equation 18] 0.1 < ΣGL_CT / TTL < 0.5

[0236] Equation 84 can set the relationship between the sum of the center thicknesses of the glass lenses and the total optical length (TTL). Equation 84 can preferably satisfy: 0.2 ≤ ΣGL_CT / TTL ≤ 0.4.

[0237] [Equation 19] 0.2 < GL_CA_Aver / PL_CA_Aver < 2

[0238] GL_CA_Aver means the average effective diameter of the glass lens having a spherical surface, and PL_CA_Aver means the average effective diameter of the glass molded lens having an aspherical surface. In Equation 19, by setting the effective diameters of the spherical lens and the aspherical lens, the path of the incident light can be effectively guided. Equation 19 preferably satisfies: 0.5 < GL_CA_Aver / PL_CA_Aver < 1.2. In an embodiment, by mixing the spherical lens and the aspherical lens in the optical system, the number of lenses can be reduced, and the deterioration of the optical characteristics can be prevented.

[0239] [Equation 20] 0 < GL_Nd_Aver / PL_Nd_Aver < 1.60

[0240] GL_Nd_Aver is the average value of the refractive indices of the glass lenses, for example, the average value of the refractive indices of the first lens and the second lens. PL_Nd_Aver is the average value of the refractive indices of the third lens and the fourth lens. Preferably, the refractive indices of the spherical lens and the aspherical lens can be set to satisfy the following condition: 1 < GL_Nd_Aver / PL_Nd_Aver < 1.5.

[0241] [Equation 20-1] ΣPL_Nd < ΣGL_Nd

[0242] ΣPL_Nd is the sum of the refractive indices of the plastic lenses, and ΣGL_Nd is the sum of the refractive indices of the glass lenses. The optical system can adjust the resolution and dispersion by setting the sum of the refractive indices of the object-side glass lenses to be higher than the sum of the refractive indices of the sensor-side plastic lenses.

[0243] [Equation 21] 5 < |Max_slope42| < 65

[0244] Max_slope42 is the maximum slope angle of the tangent line of the sensor side surface of the fourth lens relative to the optical axis. When the optical system 1000 according to the embodiment satisfies Formula 21, the optical system 1000 can control the occurrence of lens glare. Preferably, Formula 21 can satisfy: 30≤|Max slope42|≤50. In addition, the maximum slope angle of the sensor side surface of the third lens is |Max Slope32|, and can be greater than the maximum tangent angle of the fourth lens.

[0245] [Equation 22] (CG1+CG2) <CT3

[0246] CG1 is the center distance between the first lens and the second lens, and CG2 is the center distance between the second lens and the third lens. In Formula 22, the center thickness of the third lens increases, and the center distance between the first lens and the third lens decreases, so that TTL can be adjusted.

[0247] [Formula 23] LD12 <LD34

[0248] LD12 is the distance from the center of the object side surface of the object side glass material lens to the center of the object side surface of the last glass lens. For example, LD12 is the distance from the center of the object side surface of the first lens to the center of the sensor side surface of the second lens. LD34 is the distance from the center of the object side surface of the first plastic lens to the center of the sensor side surface of the last plastic lens. LD34 is the distance from the center of the object side surface of the third lens to the center of the sensor side surface of the fourth lens. In Formula 23, the optical axis distance of the plastic lens is set to be thicker than the optical axis distance of the glass lens so that light with corrected chromatic aberration can be refracted to the entire area of ​​the image sensor.

[0249] [Equation 24] 0.2 <LD12 / TTL<0.5

[0250] In Formula 24, by setting the optical axis distance of the glass lens relative to the total length (TTL), the effective diameter, curvature radius, refractive index, Abbe number, etc. of the glass lens can be set. Preferably, 0.35≤LD12 / TTL≤0.55 can be satisfied.

[0251] [Equation 25] 0.1 <CT3 / TTL<0.7

[0252] In Formula 25, by setting the center thickness of the third lens to the above range based on TTL, light incident through the first lens and the second lens can be refracted to the entire area of ​​the fourth lens, and chromatic aberration of the optical system can be improved.

[0253] [Formula 25-1] 0.4 <CT3 / ImgH<0.9

[0254] In Formula 25-1, setting the center thickness of the third lens to the above range with respect to ImgH makes it possible to reduce changes in optical characteristics due to temperature changes.

[0255] [Equation 26] 0<|L2R1 / L4R2|<10

[0256] L2R1 means the radius of curvature of the third surface of the second lens, and L4R2 means the radius of curvature of the eighth surface of the fourth lens. In Formula 28, the radius of curvature of the object-side surface of the second lens and the sensor-side surface of the fourth lens are set so that the optical power of the second lens and the fourth lens can be controlled. Therefore, good optical performance can be achieved at the center and periphery of the field of view. Preferably, Formula 26 can satisfy: 2<|L2R1 / L4R2|<5.

[0257] [Formula 27]1 <L4R1 / CT4<10

[0258] L4R1 means the radius of curvature of the object side surface of the fourth lens. If equation 27 is satisfied, the power of the fourth lens can be controlled to control the incident light as an aspherical lens, and degradation of the aspherical assembly can be prevented. Preferably, 1.5≤L4R1 / CT4<5 can be satisfied.

[0259] [Equation 28] 1<|L3R1 / L3R2|<5

[0260] L3R1 means the radius of curvature of the object-side surface of the third lens, and L3R2 means the radius of curvature of the sensor-side surface of the third lens. If equation 28 is satisfied, the third lens can be expressed as a cemented lens. Preferably, 1≤|L3R1 / L3R2|<3 can be satisfied.

[0261] [Equation 29] L1R1*L3R1<0

[0262] L1R1 and L3R1 may have radii of curvature having opposite signs on the optical axis. For example, the radius of curvature of the object-side surface of the first lens may be a positive value, and the radius of curvature of the object-side surface of the third lens may be a negative value.

[0263] [Equation 30] (Nd1*Vd1)<(Nd2*Vd2)

[0264] Nd1 and Nd2 are the refractive indices of the d-line of the first lens and the second lens, and Vd1 and Vd2 are the Abbe numbers of the first lens and the second lens. By setting the relationship between the refractive index and the Abbe number of the first lens and the second lens made of glass, the incident light can be dispersed and guided to the third lens.

[0265] [Equation 31] <CT_Max / CG_Max<5

[0266] In equation 31, the maximum center thickness CT_Max in the lens and the maximum center distance CG_Max between adjacent lenses can be set. If equation 31 is satisfied, the optical system can have good optical performance at the focal length at the set field of view, and TTL can be reduced. Preferably, the implementation can satisfy: 1.5 <CT_Max / CG_Max<3.5。

[0267] [Equation 32] 1<ΣCT / ΣCG<5

[0268] In Formula 32, ΣCT is the sum of the center thicknesses of the lenses, and ΣCG is the sum of the center distances between adjacent lenses. If Formula 32 is satisfied, the optical system can have good optical performance at a focal length at a set field of view, and TTL can be reduced. Preferably, Formula 32 can satisfy: 1.4<ΣCT / ΣCG<3.

[0269] [Equation 33]5<ΣNd<10

[0270] ΣNd means the sum of the refractive index at the d-line of each of the multiple lenses. When formula 33 is satisfied, TTL can be controlled in the optical system 1000 in which aspherical lenses and spherical lenses are mixed, and improved resolution can be achieved. In addition, a glass lens with a relatively high refractive index and a plastic lens with a relatively thick center thickness can be arranged in the optical axis direction to set TTL and the refractive index. Formula 33 can preferably satisfy: 6<ΣNd<8.

[0271] [Equation 34] 10<ΣAbbe / ΣNd<50

[0272] ΣAbbe means the sum of the Abbe numbers of each of the plurality of lenses. If equation 34 is satisfied, the optical system 1000 may have improved aberration characteristics and resolution. By setting the sum of the Abbe numbers and the sum of the refractive indices of the lenses in equation 34, the optical characteristics may be controlled, and preferably, 15<ΣAbbe / ΣNd<25 may be satisfied.

[0273] [Equation 35] Distortion < 10

[0274] Distortion means the maximum value or the absolute value of the maximum value of the distortion from the center (0.0F) to the diagonal end (1.0F) of the image sensor based on the optical characteristics detected by the image sensor 300. If the optical system 1000 satisfies Equation 35, the optical system 1000 can improve the distortion characteristics and set the conditions for image processing. Preferably, distortion <2 can be satisfied.

[0275] [Equation 36] 0.5 <CA11 / CA_Min<2.5

[0276] CA11 means the effective diameter of the object side surface of the first lens, and CA_Min means the minimum effective diameter of the object side surface and the sensor side surface of the lens. When equation 36 is satisfied, the optical system can provide a thinner module while controlling incident light and maintaining optical performance. Equation 36 preferably satisfies: 1 <CA11 / CA_Min<2。

[0277] [Formula 37]1 <CA_Max / CA_Min<5

[0278] CA_Max means the maximum effective diameter among the object-side surface and the sensor-side surface of the lens. If Equation 37 is satisfied, the optical system can be dimensioned for a slim and compact structure while maintaining optical performance. Equation 37 may preferably satisfy: 2 <CA_Max / CA_Min<3。

[0279] [Formula 38]1 <CA_Max / CA_Aver<3

[0280] CA_Aver means the average of the effective diameters of the object-side surface and the sensor-side surface of the lens. If equation 38 is satisfied, the optical system can be dimensioned for a slim and compact structure while maintaining optical performance. Equation 38 may preferably satisfy: 1.2 <CA_Max / CA_Aver<2。

[0281] [Equation 39] 0.2 <CA_Min / CA_Aver<2

[0282] If equation 39 is satisfied, the optical system can be dimensioned for a slim and compact structure while maintaining optical performance. Preferably, equation 39 can satisfy: 0.5 <CA_Min / CA_Aver<0.8。

[0283] [Equation 40] 0.5 <CA_Max / (2*ImgH)<2

[0284] Formula 40 can be set by the maximum effective diameter CA_Max of the lens surface and the diagonal length of the image sensor, and if it is satisfied, the optical system can maintain good optical performance and be sized for a slim and compact structure. Preferably, it can satisfy: 0.7 <CA_Max / (2*ImgH)<1.5。

[0285] [Equation 41] 0.5 <TD / CA_Max<4

[0286] If 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. Preferably, equation 41 can satisfy: 0.7 <TD / CA_Max<1.2。

[0287] [Equation 41-1] TD > SD

[0288] SD is the distance from the position of the aperture stop to the center of the sensor side surface of the last lens.

[0289] [Equation 42] 0 < TD / CT_Max < 0.7

[0290] In 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, 0.3 ≤ TD / CT_Max ≤ 0.4 can be satisfied.

[0291] [Equation 43] 0 < F / CA41 < 1

[0292] F means the effective focal length (EFL) of the optical system, and it can be less than 15 mm or less than 10 mm, for example, in the range of 1 mm to 10 mm. In Equation 43, the relationship between the effective focal length and the effective diameter of the object side surface of the last spherical lens is set so that the influence on reducing the optical system such as TTL can be controlled. Equation 43 preferably satisfies: 0.2 < F / CA41 < 0.5.

[0293] [Equation 44] 0 < F / L1R1 < 1

[0294] In Equation 44, the effective focal length of the optical system and the radius of curvature of the object side surface of the first lens are set so that the influence on the incident light and TTL can be controlled. Equation 44 preferably satisfies: 0.2 < F / L1R1 < 0.7.

[0295] [Equation 45] 1 < Max(CT / ET) < 3

[0296] Max(CT / ET) means 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 control the influence on the effective focal length. Equation 45 can preferably satisfy: 1.2 < Max(CT / ET) < 2.

[0297] When observing the ratio of the center thickness to the edge thickness of the glass lens and the plastic lens in the lens part, the following condition can be satisfied: Max_GL(CT / ET) < Max_PL(CT / ET). Max_GL(CT / ET) means the maximum ratio of the center thickness to the edge thickness in the glass lens, and Max_PL(CT / ET) means the maximum ratio of the center thickness to the edge thickness in the plastic lens.

[0298] [Equation 46] 0 < EPD / L1R1 < 1

[0299] EPD means the size (mm) of the entrance pupil diameter 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 may preferably satisfy: 0.3 <EPD / L1R1<0.7。

[0300] [Formula 47]0 <F1 / F3<1

[0301] F1 is the focal length of the first lens, and F3 is the focal length of the third lens. When equation 47 is satisfied, the optical power of the first lens and the third lens can be controlled to improve the resolution, and the TTL and the effective focal length (F) can be affected. Preferably, 0.2≤F1 / F3≤0.7 can be satisfied.

[0302] [Formula 47-1]F1<|F4|

[0303] [Formula 47-2]F1 <F3

[0304] [Formula 47-3]F1<|F2|

[0305] [Formula 47-4]F <F4

[0306] In Formulas 47-1 to 47-4, 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, and F4 is the focal length of the fourth lens. By controlling the power of each lens, light can be effectively guided to the aspherical lens.

[0307] The aperture stop ST is provided on the sensor side surface of the first lenses 101 and 112. The focal length of the lens provided on the sensor side closer to the aperture stop ST than the aperture stop ST and provided closest to the aperture stop ST is less than 0. The focal length F2 of the second lenses 102 and 112 must be designed to be less than 0. In this case, since the second lenses 102 and 112 have a convex meniscus shape toward the object side, the effective diameter of the object side surface of the third lenses 103 and 113 may not be increased. Since the third lens 103 has positive power, the effective diameter of the fourth lens may be increased. The composite focal length F24 of the second to fourth lenses may have positive power. That is, the composite focal length F24 of the lens arranged closer to the sensor than the aperture stop ST, i.e., the lens arranged closer to the sensor than the aperture stop, is designed to be greater than 0. In this case, the optical system can be miniaturized by reducing the TTL at the horizontal field of view FOV_H of 45 to 55 degrees.

[0308] [Equation 48]Po3*Po4<0

[0309] Po3 is the power value of the third lens, and Po4 is the power value of the fourth lens. That is, the power of the third lens and the fourth lens has opposite power, which can improve aberration and effectively guide light with an aspherical lens.

[0310] [Formula 49] 15 <Vd2-Vd3<60

[0311] In Formula 49, Vd2 is the Abbe number of the second lens, and Vd3 is the Abbe number of the third lens. When Formula 49 is satisfied, the Abbe number difference between two adjacent lenses can be kept higher than a certain value, and chromatic aberration can be improved. Formula 49 preferably satisfies: 30 <Vd2-Vd3<50。

[0312] [Formula 50]0 <F34 / F12<2

[0313] In Formula 50, by setting the relationship between the composite focal length F12 of the first lens and the second lens and the composite focal length F34 of the third lens and the fourth lens, the optical power of the glass lens and the plastic lens can be controlled to improve the resolution, and the optical system can be set in a slim and compact size. Formula 50 preferably satisfies: 1 <F34 / F12<2。

[0314] [Equation 51] 0<|F34 / F3|<2

[0315] In Formula 51, the relationship between the focal length F3 of the third lens and the composite focal length F34 of the third lens and the fourth lens is set so that the power of the plastic lens can be controlled to improve the resolution. Formula 51 preferably satisfies: 0<|F34 / F3|<1.

[0316] [Formula 52]1 <F24 / F12<5

[0317] In Formula 52, the relationship between the composite focal length F12 of the first lens and the second lens and the composite focal length F24 of the second lens to the fourth lens is set so that the composite focal length of the sensor side lens of the aperture stop is set to be greater than the composite optical power of the plastic lens, so that the composite optical power of the sensor side lens of the aperture stop can be controlled to improve the resolution. Formula 52 preferably satisfies: 2 <F24 / F12<3。

[0318] [Formula 53]|F_GL_Aver|<|F_PL_Aver|

[0319] In Formula 53, F_GL_Aver is an average value of focal lengths of glass lenses, and F_PL_Aver is an average value of focal lengths of plastic lenses. If Formula 53 is satisfied, chromatic aberration and distortion aberration can be improved by the plastic lens.

[0320] [Equation 54] <nPL / nL<1

[0321] nPL is the number of plastic lenses, and nL means the total number of lenses. In Equation 54, by arranging the number of aspherical lenses to be less than 1 times the total number of lenses, the thickness of the optical system can be reduced, and more diverse optical powers can be provided by the aspherical surfaces. Additionally, Equation 54-1 can satisfy: 0 < nGL / nL < 1, and nGL is the number of glass lenses.

[0322] [Equation 55] (CA_Max / CA_Min) < (CT_Max / CT_Min)

[0323] CA_Max is the maximum effective diameter in the lens, and CA_Min is the minimum effective diameter in the lens. CT_Max is the maximum value in the center thickness of the lens, and CT_Min is the minimum value in the center thickness of the lens. Equation 55 sets the difference in the effective diameters of the lenses to be less than the difference in the center thicknesses of the lenses, thereby improving the assemblability of the lenses.

[0324] [Equation 56] 2mm < TTL < 15mm

[0325] TTL means the distance (mm) from the center of the first surface S1 of the first lens 101 to the surface of the image sensor 300 on the optical axis OA. In Equation 56, by setting TTL to 10mm or less, a vehicle optical system can be provided. Preferably, 3mm ≤ TTL < 10mm or 3mm ≤ TTL < 8mm can be satisfied.

[0326] [Equation 57] 2mm < ImgH

[0327] Equation 57 can set 1 / 2 of the diagonal length of the image sensor 300, and can provide an optical system with a vehicle sensor size. Equation 57 can preferably satisfy: 3mm ≤ ImgH < 5mm.

[0328] [Equation 58] 1mm < BFL < 3mm

[0329] In Equation 58, BFL is set to be greater than 1mm and less than 3mm, so that the installation space for the optical filter 500 and the cover glass 400 can be ensured, and the assemblability of the components can be improved through the gap between the image sensor 300 and the last lens, and the bonding reliability can be improved. Equation 58 can preferably satisfy: 1.5mm ≤ BFL ≤ 2mm. When BFL is less than the range of Equation 58, some of the light traveling to the image sensor cannot be transmitted to the image sensor, which may be the reason for the reduction in resolution. If BFL exceeds the range of Equation 58, stray light may be introduced, which may deteriorate the aberration characteristics of the optical system.

[0330] [Equation 59] 1 < BFL / CG2 < 3

[0331] In Equation 59, by setting the center distance CG2 between the BFL and the second lens and the third lens, the joining reliability of the components can be improved according to the mounting spaces of the optical filter 500 and the cover glass 400 and the gap between the glass lens and the plastic lens. In Equation 59, it can satisfy 2.6 < BFL / CG2 < 2.5. The center distance CG2 between the first lens and the second lens can be the largest within the lens portion.

[0332] [Equation 60] 0 < CT1 / BFL < 1

[0333] In Equation 68, by setting the BFL to be greater than the center thickness of the first lens, the mounting spaces of the optical filter 500 and the cover glass 400 can be ensured, and the assembly of the components can be improved through the gap between the image sensor 300 and the last lens, and the joining reliability can be improved. If the BFL does not satisfy Equation 60, some of the light in the emitted light may not be transmitted to the effective area of the image sensor, and thus the resolution may be reduced. Preferably, it can satisfy 0.2 < CT1 / BFL < 0.6.

[0334] [Equation 61] F < 15 mm

[0335] Equation 61 can set the total effective focal length F to adapt to the vehicle optical system. Equation 61 can satisfy the range of 1 mm ≤ F ≤ 10 mm or 3 mm ≤ F ≤ 8 mm.

[0336] [Equation 62] 45 < FOV < 75

[0337] In Equation 62, FOV (field of view) means the viewing angle (degrees) in the diagonal direction of the optical system 1000, and it can provide a vehicle optical system with an angle less than 75 degrees. Preferably, it can satisfy 50 ≤ FOV ≤ 70.

[0338] [Equation 63] 0.5 < TTL / CA_Max < 1.5

[0339] CA_Max means the maximum effective diameter (mm) of the object side surface and the sensor side surface of the plurality of lenses. Equation 63 sets the relationship between the total optical axis length and the maximum effective diameter of the optical system, and it can provide an improved vehicle optical system. Equation 63 can preferably satisfy: 0.4 < TTL / CA_Max < 1.

[0340] [Equation 64] 1 < TTL / ImgH < 55

[0341] Equation 64 can set the total optical axis length TTL of the optical system and the diagonal length ImgH of the optical axis from the image sensor 300. When the optical system 1000 according to the embodiment satisfies Equation 64, the optical system 1000 can have a TTL applied to the vehicle image sensor 300, thereby providing improved image quality. Equation 64 can preferably satisfy: 1 < TTL / ImgH ≤ 1.5. It can also satisfy: TTL ≤ 10 mm.

[0342] [Equation 65] 0.1 < BFL / ImgH < 1

[0343] Equation 65 can set the optical axis distance between the image sensor 300 and the last lens and the diagonal length of the optical axis from the image sensor 300. When the optical system 1000 according to the embodiment satisfies Equation 65, the optical system 1000 can ensure the BFL for the size applied to the vehicle image sensor 300, set the distance between the last lens and the image sensor 300, and have good optical characteristics at the center and periphery of the FOV. Equation 65 preferably satisfies the following conditions: 0.3 < BFL / ImgH < 0.7, and BFL < ImgH.

[0344] [Equation 66] 1 < TTL / BFL < 10

[0345] Equation 66 can set the total optical axis length TTL of the optical system and the optical axis distance 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 ensure the BFL. Equation 66 can preferably satisfy: 2 ≤ TTL / BFL < 3.

[0346] [Equation 67] 0.5 < TTL / F < 2

[0347] Equation 75 can set the total focal length F and the total optical axis length TTL of the optical system 1000. Therefore, an optical system for a driver assistance system or a driver monitoring system can be provided. Equation 67 can preferably satisfy: 0.6 ≤ TTL / F < 1. When the optical system 1000 according to the embodiment satisfies Equation 67, the optical system 1000 can have an appropriate focal length within the set TTL range and provide an optical system that can maintain an appropriate focal length and form an image even when the temperature changes from low to high. If it is less than the lower limit of Equation 67, it is necessary to increase the optical power of the lens, making it difficult to correct spherical aberration or distortion aberration, and if it exceeds the upper limit of Equation 67, the effective diameter or TTL of the lens becomes longer, which may cause a problem of a large size of the photographing lens system.

[0348] [Equation 68] 1 < F / BFL < 10

[0349] Formula 68 can set the total effective focal length F of the optical system 1000 and the optical axis distance BFL between the image sensor 300 and the last lens. If the optical system 1000 according to the embodiment satisfies Formula 68, the optical system 1000 can have a set field of view and an appropriate focal length, and an optical system for a vehicle can be provided. In addition, the optical system 1000 can minimize the distance between the last lens and the image sensor 300, so that it can have good optical characteristics in the periphery of the FOV. Formula 68 can preferably satisfy: 2.5 <F / BFL<3.5。

[0350] [Formula 69]1 <F / ImgH<5

[0351] Equation 69 may set the total effective focal length F of the optical system 1000 and the diagonal length ImgH from the optical axis of the image sensor 300. The optical system 1000 may have improved aberration characteristics in terms of the size of the vehicle image sensor 300. Equation 69 may preferably satisfy: 1.2 <F / ImgH<2。

[0352] [Formula 70]1 <F / EPD<5

[0353] Equation 70 can set the total effective focal length F and the entrance pupil diameter of the optical system 1000. Therefore, the overall brightness of the optical system can be controlled. Equation 70 can preferably satisfy: 1 <F / EPD<3。

[0354] [Formula 71] <BFL / TD<0.5

[0355] Formula 71 can set the relationship between the optical axis distance TD and the back focal length BFL of the lens of the optical system 1000. Therefore, the resolution of the optical system can be maintained and the overall size can be controlled. Formula 71 can preferably satisfy: 0.2≤BFL / TD<0.4. When the conditional value of BFL / TD exceeds 0.5, BFL is designed to be larger than TD, so that the size of the entire optical system becomes larger, making it difficult to miniaturize the optical system, and the distance between the fourth lens and the image sensor becomes longer, so that the amount of unnecessary light between the fourth lens and the image sensor may increase, resulting in problems such as reduced resolution due to degradation of aberration characteristics.

[0356] [Formula 72] <EPD / ImgH / FOV<0.2

[0357] Equation 72 can set the relationship between the size of the EPD, the length ImgH of half the diagonal length of the image sensor, and the diagonal field of view. Therefore, the overall size and brightness of the optical system can be controlled. Preferably, Equation 72 can satisfy: <EPD / ImgH / FOV<0.1。

[0358] [Equation 73] 20 < FOV / F# < 40

[0359] Equation 73 can set the relationship between the diagonal field of view and the F-number of the optical system. Preferably, Equation 73 can satisfy: 25 < FOV / F# < 36. At this time, F# is set to 2.2 or less to provide a bright image.

[0360] [Equation 74] 1mm < ΣGL_CT * nGL < 3mm

[0361] Equation 74 can set the center thickness and the number of glass lenses by the product of the sum of the center thicknesses of the glass lenses ΣGL_CT and the number of glass lenses. Preferably, Equation 74 can satisfy: 2mm < ΣGL_CT * nGL < 3mm.

[0362] [Equation 75] 3mm < ΣPL_CT * nPL < 8mm

[0363] Equation 75 can set the center thickness and the number of plastic lenses by the product of the sum of the center thicknesses of the plastic lenses ΣPL_CT and the number of plastic lenses. Preferably, Equation 75 can satisfy: 4mm ≤ ΣPL_CT * nPL < 6mm.

[0364] [Equation 76] 5 < TTL * nGL < 10

[0365] Equation 76 can set the number of glass lenses and TTL, and can adjust dispersion and refraction angle through the glass lenses in an optical system with a TTL of 10mm or less.

[0366] [Equation 77] 4 < ImgH * nGL < 8

[0367] Equation 77 can set the number of glass lenses and ImgH, and can adjust dispersion and refraction angle through the glass lenses in an optical system with an ImgH of less than 5mm.

[0368] [Equation 78] |Max_Sag41| < |Max_Sag32|

[0369] Max_Sag41 is the maximum distance in the optical axis direction from the straight line perpendicular to the optical axis on the object side surface of the fourth lens to the object side surface of the fourth lens, and Max_Sag32 is the maximum distance in the optical axis direction from the straight line perpendicular to the optical axis on the sensor side surface of the third lens to the sensor side surface of the third lens. When Equation 78 is satisfied, the radius of curvature of the lens surface of the plastic lens can be adjusted to guide light to the entire area of the image sensor, and the effective diameters of the third lens and the fourth lens can be adjusted.

[0370] [Equation 79] |Max_Sag42| < |Max_Sag32|

[0371] Max_Sag42 is the maximum distance in the optical axis direction from a straight line perpendicular to the optical axis on the sensor side surface of the fourth lens to the sensor side surface of the fourth lens. If equation 79 is satisfied, the curvature radii of the sensor side surfaces of the third and fourth lenses can be adjusted to guide light to the entire area of ​​the image sensor, and the effective diameters of the third and fourth lenses can be adjusted.

[0372] The optical system 1000 according to the embodiment may satisfy at least one or two or more of equations 1 to 40. In this case, the optical system 1000 may have improved optical characteristics. Specifically, if 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 resolution and improved aberration characteristics and distortion characteristics. In addition, the optical system 1000 may ensure the BFL for applying the vehicle image sensor 300, compensate for the degradation of the optical characteristics due to temperature changes, and minimize the distance between the last lens and the image sensor 300, thereby providing good optical performance at the center and periphery of the FOV.

[0373] Table 1 shows the terms of the above formula in the optical system 1000 of the embodiment, including TTL (mm), BFL, effective focal length F (mm), ImgH (mm), effective diameter CA (mm), thickness (mm), TD (mm) which is the optical axis distance from the first surface S1 to the eighth surface S8, the focal length F1, F2, F3 and F4 (mm) of each of the first lens to the fourth lens, the sum of the refractive index, the sum of the Abbe number, the sum of the center thickness of each lens (mm), the sum of the distances between adjacent lenses, the diagonal FOV (degrees), the edge thickness ET, the focal length of the first lens group and the second lens group, the composite focal length of the second lens to the fourth lens, the F number, etc.

[0374]

Table 1

[0375]

[0376]

[0377] Table 2 shows the result values ​​of the above-mentioned formulas 1 to 40 in the optical system 1000 of the first embodiment and the second embodiment. 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 the formulas 1 to 40. Therefore, the optical system 1000 can have good optical performance and excellent optical characteristics at the center and periphery of the FOV.

[0378]

Table 2

[0379]

[0380]

[0381]

[0382] Table 3 shows the result values ​​of the above equations 41 to 79 in the optical system 1000 of the first embodiment and the second embodiment. 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 equations 41 to 79. Therefore, the optical system 1000 can have good optical performance and excellent optical characteristics at the center and periphery of the FOV.

[0383]

Table 3

[0384]

[0385]

[0386]

[0387] Will refer to Figures 21 to 34 An optical system and a camera module according to a third embodiment of the present invention will be described. Fig.21 As shown, the optical system 1000 according to the third embodiment of the present invention may include five or more lenses. The optical system 1000 and the camera module having the optical system 1000 may be installed inside or outside the vehicle to monitor the driver or sense external objects or lanes. The material of the lens may be selected from glass or plastic, and the linear expansion coefficient of the glass material is lower than the linear expansion coefficient of the plastic material. Therefore, a glass lens is used to suppress the change of the focal imaging position due to temperature changes. However, glass lenses are expensive compared to plastic lenses, and there is a problem that it is difficult to meet the requirements of low cost. Therefore, it is required that the lens in the optical system 1000 has a mixed configuration of glass lenses and plastic lenses. By adopting these plastic lenses, the optical system 1000 can provide weight reduction and low cost, because the thickness of the plastic lens can be reduced, and due to the plastic lens, various aberrations such as spherical aberration and chromatic aberration can be well corrected. In addition, since the plastic lens can provide an aspherical lens, the distortion portion of the peripheral area can be minimized.

[0388] The optical system 1000 may include n lenses, where n is an integer greater than or equal to 5, for example, 5 to 8. The ratio of plastic material lenses to glass material lenses in the n lenses may be in the range of 2:3 to 2:6 or 3:4 to 3:5.

[0389] The number of lenses of the second lens group LG2 may be greater than the number of lenses of the first lens group LG1, for example, may be greater than 4 times the number of lenses of the first lens group LG1 or greater than 5 times the number of lenses of the first lens group LG1. The first lens group LG1 may have 3 lenses or less. The first lens group LG1 may preferably be one lens. The second lens group LG2 may include two or more lenses. The second lens group LG2 may include four to seven lenses. The second lens group LG2 may preferably be six lenses.

[0390] The first lens group LG1 may include at least one lens made of glass. The first lens group LG1 may set the lens closest to the object side to a lens made of glass. Such a glass material has a small amount of expansion and contraction changes due to external temperature changes, and the surface is not easily scratched, so that surface damage can be prevented. The lens material of the second lens group LG2 may be a mixture of at least one lens made of glass and at least one lens made of plastic. In the second lens group LG2, at least one lens made of plastic may be arranged closer to the sensor side than a lens made of glass. The second lens group LG2 may include two or more lenses made of glass, for example, two to four lenses made of glass. As another example, the second lens group LG2 may have one or more lenses made of plastic. The second lens group LG2 may include two or more lenses made of plastic, for example, two to four lenses made of plastic.

[0391] At least one lens closest to the image sensor 300 in the optical system 1000 may be made of plastic. For example, at least two lenses closest to the image sensor 300 may be made of plastic, and preferably, at least three lenses adjacent to the image sensor 300 may be made of plastic. That is, since the n-th lens, the n-1-th lens, and the n-2-th lens in the optical system 1000 are arranged as plastic lenses, various aberrations can be corrected for the incident light of the image sensor 300. In the optical system 1000, at least two lenses closest to the object may be made of glass. Three or more lenses, for example, three to five lenses, closest to the object may be made of glass. Since the glass lens has a smaller contraction and expansion rate than the plastic lens due to temperature changes, the glass lens may be placed in the region adjacent to the outside of the lens barrel.

[0392] Each of the lenses 121 to 127 may have an object side surface and a sensor side surface. The optical system may have a greater number of lenses having an aspherical sensor side surface and an aspherical object side surface than the number of plastic lenses. The optical system may have a lesser number of lenses having a spherical sensor side surface and a spherical object side surface than lenses having aspherical surfaces on both sides. Since the optical system 1000 has more aspherical lenses than spherical lenses, it can correct various aberrations. In the optical system 1000, the lens with the maximum refractive index may be located adjacent to the first lens group LG1 or the object. The maximum refractive index may be 1.7 or greater. The dispersion of light incident through the lens with the maximum refractive index may be increased, and the center thickness may be thinner than the edge thickness. In addition, since the lens with the maximum refractive index is located on the object side, the radius of curvature of the second lens and subsequent lenses may be easily changed, and the center thickness may be increased.

[0393] In the optical system 1000, the lens with the largest effective diameter may be a lens close to the object side, or one of the lenses between the two lenses on the object side and the two lenses on the sensor side. Preferably, the lens with the largest effective diameter may be located between lenses made of glass. The effective diameter may be the diameter of the effective area where effective light is incident from each lens. The effective diameter is the length in the directions X and Y orthogonal to the optical axis, and is the average of the effective diameter of the object side surface of each lens and the effective diameter of the sensor side surface. Embodiments of the present invention can reduce the weight of the camera module by further mixing plastic lenses in the optical system 1000, provide lower manufacturing costs, suppress the degradation of optical characteristics due to temperature changes, and various types of plastic lenses can replace glass lenses, and polishing and processing of lens surfaces such as aspherical or free-form surfaces can be easily performed.

[0394] TTL may be greater than 2 times of ImgH, for example greater than 4 times and less than 12 times. The effective focal length EFL within the optical system 1000 is provided to be 10 mm or greater, and the FOV is provided to be less than 45 degrees, so that it can be provided as a standard optical system in a vehicle camera module. For example, the optical system and the camera module according to the embodiment may be applied to a camera of an ADAS (Advanced Driver Assistance System) installed inside or outside a vehicle. The condition of TTL / (2*ImgH) may be 2.5 or greater or 2.7 or greater, and may be, for example, in the range of 2.5 to 5 or 3.5 to 5. By setting the value of TTL / (2*ImgH) to 2.5 or greater and 5 times or less, a vehicle lens optical system may be provided. Therefore, the optical system 1000 may provide an image without exaggeration or distortion for the formed image.

[0395] The effective diameter of at least one or all plastic lenses within the optical system 1000 may be smaller than the length of the image sensor 300. The number of lenses within the optical system 1000 whose effective diameter is larger than the length of the image sensor 300 may be 50% or more or 60% or more, and the number of lenses whose effective diameter is smaller than the length of the image sensor 300 may be less than 50% or less than 40%. The optical system 1000 may include at least one cemented lens 134 therein. The cemented lens 145 may be a lens in which at least two lenses having different refractive powers are cemented, and the distance between the two lenses may be less than 0.01 mm. The cemented lens 134 may be a lens in which two lenses having different focal lengths are bonded. The two lenses may be bonded using an adhesive. The effective diameter of at least one lens or all lenses arranged on the object side based on the cemented lens 134 may be larger than the length of the image sensor 300. The effective diameter of at least one lens arranged on the sensor side based on the cemented lens 134 may be smaller than the length of the image sensor 300. In addition, the object side lens 123 in the cemented lens 134 may be larger than the length of the image sensor 300, and the sensor side lens 124 may be larger than the length of the image sensor 300. The lens between the cemented lens 134 and the first lens 121 may be made of glass. The lens arranged between the cemented lens 134 and the image sensor 300 may be made of plastic. The lens between the cemented lens 134 and the first lens 121 may be a lens having spherical surfaces on both sides. The lens arranged between the above-mentioned cemented lens 134 and the image sensor 300 may be an aspherical lens on both sides. The two side surfaces are the object side surface and the sensor side surface. Therefore, by arranging the aspherical lens between the cemented lens 134 and the image sensor 300, the optical performance can be improved by correcting the curvature aberration and the chromatic aberration.

[0396] The optical axis distance between the first lens group LG1 and the second lens group LG2 may be 1 times or less of the optical axis distance of the first lens group LG1, and may be, for example, in the range of 0.1 times to 1 times of the optical axis distance of the first lens group LG1. The optical axis distance between the first lens group LG1 and the second lens group LG2 may be 0.2 times or less of the optical axis distance of the second lens group LG2, and may be, for example, in the range of 0.01 times to 0.2 times. The sensor side surface of the first lens group LG1 closest to the sensor side may be convex, and the object side surface of the second lens group LG2 closest to the object may be convex. The first lens group LG1 may diverge light incident through the object side, and the second lens group LG2 may refract light diverged through the first lens group LG1 into the area of ​​the image sensor 300.

[0397] The first lens group LG1 may have a negative (-) refractive power, and the second lens group LG2 may have a positive (+) refractive power. The first lens 121 of the first lens group LG1 may have a negative (-) refractive power, and the last lens of the second lens group LG2 may have a negative (-) refractive power. When the focal length is expressed as an absolute value, the focal length of the first lens group LG1 may be greater than the focal length of the second lens group LG2, for example, 2 times or greater, for example, 2 times to 10 times. The effective focal length (EFL) of the optical system 1000 may be less than the absolute value of the focal length of the first lens group LG1. The EFL may be less than the absolute value of the focal length of the first lens group LG1 and greater than the absolute value of the focal length of the second lens group LG2.

[0398] The number of lenses having negative (-) refractive power on the optical system 1000 may be equal to or greater than the number of lenses having positive (+) refractive power. The number of lenses having negative (-) refractive power may be 50% or greater of the total number of lenses. The average refractive index of the lenses having negative refractive power may be greater than the average value of the lenses having positive refractive power. Therefore, the dispersion value of the lenses having positive refractive power may be greater than the dispersion value of the lenses having negative refractive power.

[0399] The lens portion 100B may be a mixture of glass lenses and plastic lenses. The number of lenses made of plastic may be 60% or less of the total number of lenses, and may be in the range of 30% to 60% or 30% to 50%. Therefore, when a plastic lens is further arranged in the camera module, the weight of the camera module may be reduced, and the camera module is easy to polish and process due to the plastic material, resists external impact, has high price competitiveness, and is easy to ensure the material. In addition, various aberrations may be corrected by the plastic lens, so that the optical performance may be prevented from being deteriorated.

[0400] The lens portion 100B may include a lens made of a first material that is continuously aligned along the optical axis OA and a lens made of a second material that is continuously aligned along the optical axis on the sensor side of the lens made of the first material. The first material may be a glass material, and the second material may be a plastic material. The lens portion 100B may include a lens of the first material having an aspherical surface that is continuously aligned along the optical axis OA, a lens of the first material having a spherical surface that is continuously aligned along the optical axis on the sensor side of the lens having a spherical surface, and a lens of the second material having an aspherical surface that is continuously aligned along the optical axis on the sensor side of the lens having a spherical surface. The first material may be a glass material, and the second material may be a plastic material.

[0401] The effective diameter of the lens closest to the object side in the lens portion 100B may be larger than the effective diameter of the lens closest to the image sensor 300. Therefore, the brightness of the optical system can be controlled. The effective diameter may be the average effective diameter of the object side surface and the sensor side surface of each lens. By controlling the effective diameter size of each of the lenses, the optical system 1000 may control incident light to compensate for degradation of resolution and optical characteristics due to temperature changes, improve chromatic aberration control characteristics, and improve vignetting characteristics of the optical system 1000. The lens portion 100B may include a first lens 121, a second lens 122, a third lens 123, a fourth lens 124, a fifth lens 125, a sixth lens 126, and a seventh lens 127 aligned along the optical axis from the object side to the sensor side.

[0402] In the lens section 100B, when the focal length is an absolute value, the focal length of the lens closest to the object may be greater than the focal length of the plastic lens. Here, the plastic lens may be at least one lens arranged on the sensor side of the cemented lens, or at least one lens adjacent to the image sensor. The focal length F1 of the first lens 121 may be the largest in the optical system and may be greater than the focal length (absolute value) of the second lens group LG2. That is, the following condition may be satisfied: |FLG2| <F1。

[0403] When the focal length is expressed as an absolute value, the composite focal length of the lens of the first material may be smaller than the composite focal length (absolute value) of the lens of the second material. The first material may be a glass material, and the second material may be a plastic material. The composite focal length of the first lens 121 to the fourth lens 124 may be smaller than the composite focal length (absolute value) of the fifth lens 125 to the seventh lens 127. Here, the composite focal length of the lens of the first material or the first lens 121 to the fourth lens 124 may be greater than 0, and the composite focal length of the lens of the second material or the fifth lens 125 to the seventh lens 127 may be less than 0. Therefore, the optical system 1000 in which the first material lens and the second material lens are stacked can set the focal length.

[0404] In the center thickness CT of the lens, for example, at least two or more of the glass lenses may have a center thickness greater than the center thickness of the plastic lens. If the average value of the center thickness of the glass lenses in the lens portion 100B is GL CT _Aver, and the average value of the center thickness of the plastic lens is PL CT _Aver, then the following conditions can be met: GL CT _Aver>PL CT _Aver. In addition, the following conditions can be met: 1.1 <GL CT _Aver / PL CT _Aver<2.

[0405] The lens closest to the object in the lens section 100B may have the maximum refractive index, and the maximum refractive index may be 1.7 or greater, for example, 1.75 or greater. The refractive index of the lens closest to the object may be greater than that of the plastic lens. The average refractive index of the plastic lenses in the lens section 100B may be less than 1.6, and the average refractive index of the glass lenses may be 1.6 or greater. In the lens section 100B, if the average refractive index of the glass material lenses is GLn_Aver and the average refractive index of the plastic lenses is PLn_Aver, the following condition may be satisfied: PLn_Aver < GLn_Aver. Additionally, the following condition may be satisfied: 1 < GLn_Aver / PLn_Aver < 1.2. Additionally, the average refractive index difference may satisfy the following condition: GLn_Aver - PLn_Aver ≥ 0.5. The lens with a high refractive index is located on the object side of the plastic lens, thereby increasing chromatic aberration.

[0406] The average Abbe number of the glass material lenses in the lens section 100B may be greater than the average Abbe number of the plastic lenses. The number of glass lenses having an Abbe number lower than the average Abbe number of the plastic material lenses in the lens section 100B may be 2 or less, for example, 1. When the average Abbe number of the glass material lenses is GLv_Aver and the average Abbe number of the plastic lenses is PLv_Aver, the following condition may be satisfied: PLv_Aver < GLv_Aver. Additionally, the following condition may be satisfied: 1 < GLv_Aver / Plv_Aver < 1.5. The lens with a low Abbe number may improve chromatic aberration at the position adjacent to the image sensor 300.

[0407] In the lens section 100B, the number of lenses with an effective diameter larger than the average effective diameter of the plastic lenses can be 3 or more, for example 4 or more. When the average effective diameter of the plastic material lens is PLca_Aver and the average effective diameter of the glass material lens is GLca_Aver, the following conditions can be satisfied: PLca_Aver < GLca_Aver. Additionally, the following condition can be satisfied: 1 < GLca_Aver / PLca_Aver < 1.5. Additionally, the relationship between the length of the image sensor 300 and the average effective diameter PLca_Aver of the plastic lens can satisfy the following condition: 1 ≤ PLca_Aver / (ImgH * 2) < 1.5. Additionally, the relationship between the average effective diameter of the glass material and the length of the image sensor 300 can satisfy the following condition: 1.1 < GLca_Aver / (ImgH * 2) < 1.5. The difference between the maximum length of the image sensor 300 and the effective diameter of the plastic lens can be arranged to be small. Therefore, by arranging the plastic lenses with small effective diameters adjacent to the image sensor 300, the plastic lenses can disperse the color from the center to the periphery of the image sensor 300.

[0408] The average effective diameter of the glass material can be 10 mm or more, for example in the range of 10 mm to 15 mm. The average effective diameter of the plastic material can be 8 mm or more, for example in the range of 8 mm to 12 mm. The lens with the minimum effective diameter can be made of plastic material, and the lens with the maximum effective diameter can be made of glass material. The minimum effective diameter within the lens section 100B can be in the range of 7 mm to 10 mm, and the maximum effective diameter can be in the range of 11 mm to 15 mm. Therefore, the optical system 1000 can improve the resolution and chromatic aberration control characteristics by controlling the incident light, and can improve the vignetting characteristics of the optical system 1000.

[0409] If the radius of curvature is described as an absolute value, the lens surface with the smallest radius of curvature relative to the optical axis OA in the lens portion 100B may be the object side surface of the first plastic lens in the plastic lens. The lens surface with the smallest radius of curvature may be the object side surface of the plastic lens closest to the glass lens. For example, the object side surface of the n-2 lens may have the smallest radius of curvature in the lens portion 100B. Therefore, the effective diameter may refract light into the effective area of ​​the plastic lens smaller than the glass lens. The lens surface with the largest radius of curvature in the lens portion 100B may be the sensor side surface or the object side surface of one of the plastic lenses arranged between the glass lens and the image sensor 300. In the case of two or more plastic lenses, the lens surface with the largest radius of curvature may be the plastic lens with the smallest Abbe number or the largest refractive index in the plastic lens, and may be, for example, the object side surface of the n-1 lens. For example, the object side surface of the n lens may have the largest radius of curvature in the lens portion 100B.

[0410] The length of the image sensor 300 is the maximum length in the diagonal direction orthogonal to the optical axis OA, and may be smaller than the effective diameter of the lens closest to the object in the first lens group LG1, and may be larger than the effective diameter of the lens closest to the sensor in the second lens group LG2. Here, the number of lenses having an effective diameter greater than the length of the image sensor 300 may be 4 to 6, and the number of lenses having an effective diameter less than the length of the image sensor 300 may be 1 to 3.

[0411] In the lens arranged between the object and the aperture stop ST, the effective diameter of the lens surface tends to increase as it goes from the object side to the aperture stop. In the lens surface arranged between the aperture stop and the sensor, the effective diameter of the lens surface tends to decrease as it goes from the aperture stop to the sensor side. The meaning that the effective diameter of the lens surface tends to increase or decrease does not only mean the case where the effective diameter of the lens surface increases or decreases. For example, it also includes the case where the effective diameter of the lens surface increases and then decreases as it goes from the aperture stop to the sensor side. The lens surface on which the aperture stop is provided is designed to have an effective diameter smaller than the effective diameter of the lens surface on the object side of the aperture stop or the lens surface on the sensor side. The lens surface on which the aperture stop is provided is intended to more effectively control and guide the amount of light in the optical system. In the case where the aperture stop is provided on the object side surface of the second lens as in the third embodiment, the following conditions are satisfied: the effective diameter of the sensor side surface of the second lens>the effective diameter of the sensor side surface of the first lens>the effective diameter of the object side surface of the second lens. The following condition is satisfied: effective diameter of the sensor-side surface of the second lens < effective diameter of the object-side surface of the third lens > effective diameter of the object-side surface of the third lens.

[0412] The aperture stop ST may be arranged on the periphery of the object-side surface or the sensor-side surface of the lens closest to the object side among the lenses of the second lens group LG2. Alternatively, the aperture stop may be arranged on the periphery of the object-side surface or the sensor-side surface of the object-side lens of the first lens group LG1. Alternatively, at least one lens selected from a plurality of lenses may perform the function of the aperture stop. Specifically, the object-side or sensor-side surface of one lens selected from the lenses of the optical system 1000 may be used as an aperture stop for controlling the amount of light.

[0413] In the optical system 1000 of the third embodiment, the sum of the refractive indexes of the lenses of the lens portion 100B may be 8 or more, for example, in the range of 8 to 15, and the average value of the refractive index may be in the range of 1.58 to 1.7. The sum of the Abbe numbers of each of the lenses may be 220 or more, for example, in the range of 220 to 350, and the average value of the Abbe numbers may be 55 or less, for example, in the range of 31 to 55. The sum of the center thicknesses of the entire lens may be 17 mm or more, for example, in the range of 20 mm to 35 mm, and the average value of the center thicknesses may be in the range of 2.8 mm to 5 mm. The sum of the center distances between the lenses on the optical axis OA may be 4.5 mm or more, for example, in the range of 4.5 mm to 9 mm, and may be less than the sum of the center thicknesses of the lenses. In addition, the average value of the effective diameters of each lens surface S1 to S14 of the lens portion 100B may be set to 8 mm or more, for example, in the range of 8 mm to 15 mm.

[0414] In the optical system according to the third embodiment, the field of view (diagonal FOV) may be 50 degrees or less, for example, in the range of 20 to 50 degrees. The F number of the optical system or camera module may be 2.4 or less, for example, in the range of 1.4 to 2.4 or in the range of 1.5 to 1.8. In the optical system according to the third embodiment of the present invention, the maximum field of view (diagonal FOV) may be 50 degrees or less, for example, in the range of 20 to 50 degrees. The vehicle optical system may have a horizontal field of view FOV_H greater than 20 degrees and less than 40 degrees, for example, in the range of 25 to 35 degrees in the Y-axis direction. In addition, the vertical field of view is set at a smaller angle than the horizontal field of view, and may be less than 20 degrees, for example, in the range of 10 to 20 degrees. At this time, the sensor length in the horizontal direction Y may be 8.064 mm ± 0.5 mm, and the sensor height in the vertical direction X may be 4.54 mm ± 0.5 mm. The horizontal field of view FOV_H is a field of view based on the horizontal length of the sensor. Therefore, the change in the focus position caused by the temperature change can be suppressed, and it can be provided as a vehicle imaging device in which various aberrations are well corrected.

[0415] Since the third embodiment is an optical system applied to a vehicle camera device, the first lens 121 can be set to a glass material even if a plastic lens and a glass lens are designed together. This has the advantage that the glass material is more scratch-resistant than a plastic material and is insensitive to external temperature. In order to more effectively prevent scratches caused by foreign matter or when placed inside a vehicle, a glass lens is used as the first lens 121, and the object side surface of the first lens 121 may have a concave shape so as not to contact an external structure. If the object side surface of the first lens 121 is designed to have a convex shape, scratches may occur due to contact with an external structure. For driver monitoring during vehicle operation, front / rear photography of the vehicle, lane detection, and detection of unexpected objects around the vehicle, the field of view may be greater than 20 degrees and less than 40 degrees, for example, within a range of 25 degrees to 35 degrees. The horizontal field of view may be an angle preset for an advanced driver assistance system (ADAD). The optical system 1000 according to the third embodiment may also include a reflective member (not shown) for changing the light path. The reflective member may be implemented as a prism that reflects the incident light of the first lens group LG1 toward the lens. Hereinafter, an optical system according to a third embodiment will be described in detail.

[0416] Reference Figure 21 to Figure 24 , the lens part 100B may include first to seventh lenses 121 to 127. The first lens 121 may be a first lens group LG1, and the second to seventh lenses 122, 123, 124, 125, 126, and 127 may be a second lens group LG2. An aperture stop ST may be provided around an object-side surface of the second lens 122.

[0417] The first lens 121 may have a positive (+) or negative (-) refractive power on the optical axis OA. The first lens 121 may have a negative (-) refractive power. The first lens 121 may include a plastic material or a glass material, and may be, for example, a glass material. The first lens 121 made of a glass material may reduce changes in the center position and the radius of curvature due to temperature changes in the surrounding environment, and may protect the incident side surface of the optical system 1000. The first surface S1 of the first lens 121 may be concave on the optical axis, and the second surface S2 may be convex. The first lens 121 may have a meniscus shape that bulges toward the sensor. Differently, the first surface S1 may have a convex shape on the optical axis OA, and the second surface S2 may have a concave shape. The first lens 121 may be made of a glass material and may have an aspherical surface. The aspherical coefficients of the first surface S1 and the second surface S2 may be set to Fig.24S1 and S2 in L1. The first lens 121 can be manufactured as a lens having an aspherical surface by injection molding a glass material. Since the first lens 121 is set to an aspherical glass material, the glass material with high transmittance and refractive index has an aspherical surface, so that the number of lenses in the optical system can be reduced. The number of lenses made of aspherical glass material in the optical system 1000 can be less than the number of plastic lenses. The effective radius r11 of the first lens 121 can be greater than the effective radius of the plastic lens. Alternatively, at least one of the object-side surface and the sensor-side surface of the first lens 121 can have a free surface, that is, a non-rotationally symmetric surface.

[0418] Since the first surface S1 of the first lens 121 is concave and the second surface S2 is convex, the incident light can be refracted in a direction away from the optical axis OA, and the distance between the first lens 121 and the second lens 122 can be reduced. In addition, due to the shape of the lens surface of the first lens 121, the effective diameter of the sensor side surface of the second lens 122 can be designed to be larger than the effective diameter of the object side surface. The first surface S1 of the first lens 121 can be set to have no critical point from the optical axis OA to the end of the effective area, that is, the edge. The second surface S2 of the first lens 121 can be set to have no critical point.

[0419] The refractive index Nd1 of the first lens 121 may satisfy the following conditions: Nd1>1.7 or Nd1>1.75. Since the refractive index Nd1 of the first lens 121 is the largest in the lens portion 100B, the radius of curvature of the first lens 121 and the second lens 122 may be increased, and lens manufacturing may be facilitated. If the refractive index Nd1 of the first lens 121 is less than the above conditions, in order to increase the refractive power of the first lens 121 and the second lens 122, the lens surface must form a sharp concave or convex, and in this case, lens manufacturing is not easy, the lens defect rate increases, and it will lead to a decrease in the yield rate.

[0420] The second lens 122 may be arranged between the first lens 121 and the third lens 123. The second lens 122 may have a positive (+) refractive power. The second lens 122 may be set to a glass material. On the optical axis OA, the third surface S3 of the second lens 122 may be convex, and the fourth surface S4 may be convex. The first lens 121 may have a shape with convex sides. The second lens 122 may be made of glass and may be spherical, and the third surface S3 and the fourth surface S4 may be spherical.

[0421] Since both sides of the second lens 122 are set to be convex, the TTL and the number of lenses of the optical system can be minimized, and the light can be refracted efficiently. The second lens 122 can satisfy the following condition: L2R1>|L2R2|. When this condition is met, the light is effectively refracted by the fourth surface S4, and the effective diameter of the fourth lens 124 to the seventh lens 127 can be guided without increasing, and the TTL can be reduced. If the following condition is met: L2R1<|L2R2|, a large amount of aberration may occur on the object side surface of the second lens 122, the light refraction efficiency may be reduced on the sensor side surface, the effective diameter of the rear lens may be increased, and the TTL may also be increased.

[0422] Since the first lens 121 having a large refractive index and a small Abbe number and the second lens 122 having a small refractive index and a large Abbe number are stacked, the chromatic aberration of the optical system can be corrected. In addition, in order to reduce the aberration caused by the spherical refractive surface of the second lens 122, the refractive surface of the first lens 121 can be set to an aspherical surface.

[0423] The aperture stop ST may be disposed around the object-side third surface S3 of the second lens 122. Since the second lens 122 adjacent to the sensor side of the aperture stop has a positive refractive power (F2>0), the second lens 122 may refract the incident light in the optical axis direction, and an increase in the effective diameter of the sensor side or rear side lens of the second lens 122 may be suppressed. Therefore, the weight yield of the optical system may be prevented from being reduced by the second lens 122, and production efficiency may be improved. Here, the composite focal length of the second lens 122 to the seventh lens 127 arranged on the sensor side of the aperture stop may have a positive value, and the TTL may be reduced within the field of view.

[0424] The third lens 123 may have a positive (+) refractive power. The third lens 123 may be set as a glass material. The fifth surface S5 of the third lens 123 on the optical axis may be convex, and the sixth surface S6 may be convex. The third lens 123 may have a shape in which both sides are convex on the optical axis OA. Differently, the third lens 123 may have a meniscus shape convex on the object side or the sensor side. Alternatively, the third lens 123 may have a shape in which both sides are concave on the optical axis. The third lens 123 may be made of glass and may be spherical, and the fifth surface S5 and the sixth surface S6 may be spherical.

[0425] The fourth lens 124 may have a positive (+) or negative (-) refractive power on the optical axis OA. The fourth lens 124 may have a negative (-) refractive power different from the refractive power of the third lens 123. The fourth lens 124 may include a plastic or glass material. For example, the fourth lens 124 may be set to a glass material. The seventh surface S7 of the fourth lens 124 on the object side on the optical axis may be concave, and the eighth surface S8 on the sensor side may be concave. The fourth lens 124 may be concave on both sides. In this way, the fourth lens 124 may have a convex meniscus shape toward the object side or the sensor side. In this way, the fourth lens 124 may have a shape in which both sides are convex on the optical axis OA. The fourth lens 124 may be made of glass and may have a spherical surface, and the seventh surface S7 and the eighth surface S8 may be spherical.

[0426] The third lens 123 and the fourth lens 124 may be bonded. The bonding surface between the third lens 123 and the fourth lens 124 may be defined as a sixth surface S6. The sixth surface S6 may be the same surface as the seventh surface of the fourth lens 124. The object side surface of the cemented lens 134 may be convex, and the sensor side surface may be concave. The distance between the third lens 123 and the fifth lens 124 may be less than 0.01 mm, and may be bonded with an adhesive. The distance between the third lens 123 and the fourth lens 124 may be less than 0.01 mm from the optical axis OA to the end of the effective area. The third lens 123 and the fourth lens 124 may have opposite refractive powers. The composite refractive power of the third lens 123 and the fourth lens 124 may have positive refractive power.

[0427] The product of the refractive power of the object-side third lens 123 of the cemented lens 134 and the refractive power of the sensor-side fourth lens 124 may be less than 0. The product of the focal length of the object-side third lens 123 of the cemented lens 134 and the focal length of the sensor-side fourth lens 124 may be less than 0. Therefore, the aberration characteristics of the optical system can be improved. If the refractive powers of the two lenses of the cemented lens 134 are the same, there is a limit to the improvement of the aberration.

[0428] The combined refractive power of the cemented lens 134 has a positive refractive power, and based on the second lens 122 on the object side of the cemented lens 134 and the sixth lens 126 on the sensor side, it may have a positive refractive power. Therefore, the second lens 122, the cemented lens 134, and the fifth lens 125 can refract some of the incident light in the optical axis direction and can correct chromatic aberration with each other. The effective diameter of the third lens 123 can be larger than the diagonal length of the image sensor 300. The effective diameter of the third lens 123 is the average of the effective diameters of the seventh surface S7 and the sixth surface S6, and can be larger than the diagonal length of the image sensor 300. The effective diameter of the fourth lens 124 can be smaller than the effective diameter of the third lens 123 and larger than the diagonal length of the image sensor 300.

[0429] If the effective diameter of the fifth surface S5 of the third lens 123 is CA31 and the effective diameter of the sixth surface S6 is CA32, the effective diameters of the fifth surface S5 and the sixth surface S6 can satisfy the following condition: 0.5 < CA31 / CA32 < 1. If the effective diameter of the seventh surface of the fourth lens 124 is CA41 and the effective diameter of the eighth surface S8 is CA42, the effective diameters of the seventh surface and the eighth surface can satisfy the following condition: 1 < CA41 / CA42 < 1.5. The cemented lens 134 is joined to a glass lens having a different refractive index and has a spherical refracting surface. If the lens disposed on the sensor side compared to the cemented lens 134 is an aspherical lens or a plastic lens, spherical aberration can be compensated. Additionally, since the lens disposed on the sensor side compared to the cemented lens 134 is a plastic lens and is set as a lens having a small effective diameter, the light traveling through the plastic lens to the image sensor 300 can be effectively guided. Since the position of the cemented lens 134 is in the middle or in front of the middle in the lens portion 100B, chromatic aberration correction can be more effective.

[0430] The fifth lens 125 can have a positive (+) refractive power. The fifth lens 125 can include a plastic or glass material. For example, the fifth lens 125 can be set as a plastic material. On the optical axis OA, the ninth surface S9 on the object side of the fifth lens 125 can be convex, and the tenth surface S10 on the sensor side can be concave. Alternatively, the fifth lens 125 can have a convex shape on both sides. The fifth lens 125 can be made of a plastic material and can have an aspherical surface. At least one of the ninth surface S9 and the tenth surface S10 can be aspherical. For example, both the ninth surface S9 and the tenth surface S10 can be aspherical. The aspherical coefficients of the ninth surface and the tenth surface S10 can be set to Fig.24 L5S1 and l5S2 of. At least one or both of the ninth surface S9 and the tenth surface S10 of the fifth lens 125 can be set to have no critical points from the optical axis OA to the end of the effective region.

[0431] The sixth lens 126 may have a positive (+) or negative (-) refractive power on the optical axis OA. The sixth lens 126 may have a negative (-) refractive power. The sixth lens 126 may include a plastic or glass material. For example, the sixth lens 126 may be set to a plastic material. The eleventh surface S11 of the sixth lens 126 on the object side on the optical axis OA may be convex, and the twelfth surface S12 on the sensor side may be concave. Differently, the sixth lens 126 may have a convex shape on both sides. Alternatively, the sixth lens 126 may have a convex meniscus shape facing the sensor. At least one or both of the eleventh surface S11 and the twelfth surface S12 may be aspherical. The aspherical coefficients of the eleventh surface S11 and the twelfth surface S12 may be set to Fig.24 Alternatively, at least one of the object-side surface and the sensor-side surface of the sixth lens 126 may have a free-form surface, that is, a non-rotationally symmetric surface.

[0432] The eleventh surface S11 and the twelfth surface S12 of the sixth lens 126 may be arranged to have no critical point from the optical axis OA to the end of the effective area. When the twelfth surface S12 has a critical point, it may be located at 70% or more of the effective radius r62 from the optical axis OA, or in the range of 70% to 90%, or in the range of 75% to 85%.

[0433] The seventh lens 127 may have a negative (-) refractive power. The seventh lens 127 may include a plastic or glass material. For example, the seventh lens 127 may be made of a plastic material. The object-side thirteenth surface S13 of the seventh lens 127 on the optical axis may be convex, and the sensor-side fourteenth surface S14 may be concave. The seventh lens 127 may have a meniscus shape convex toward the object side. Alternatively, on the optical axis OA, the thirteenth surface S13 may have a convex shape, and the fourteenth surface S14 may have a concave shape. At least one of the thirteenth surface S13 and the fourteenth surface S14 may be aspherical. For example, both the thirteenth surface S13 and the fourteenth surface S14 may be aspherical. The aspherical coefficients of the thirteenth surface S13 and the fourteenth surface S14 may be set to Fig.24 Alternatively, at least one of the object-side surface and the sensor-side surface of the seventh lens 127 may have a free surface, that is, a non-rotationally symmetric surface.

[0434] The seventh lens 127 may be a plastic lens closest to the image sensor 300. In addition, by arranging two or more of the plastic lenses adjacent to the image sensor 300, aberrations such as spherical aberration and chromatic aberration may be improved by a lens surface having an aspherical surface, and the influence on the resolution may be controlled. In addition, by arranging the plastic lens as a lens adjacent to the image sensor 300, the plastic lens may be insensitive to assembly tolerances compared to a glass lens. In other words, insensitivity to assembly tolerances means that even if the assembly is slightly different from the design during assembly, the optical performance may not be significantly affected. In addition, by setting the three lenses 125, 126, and 127 adjacent to the image sensor 300 to a plastic material, the optical performance may be improved by a lens surface having an aspherical surface, and, for example, aberration characteristics may be improved and resolution degradation may be prevented.

[0435] Reference Fig. 22 , BFL is the optical axis distance from the image sensor 300 to the center of the sensor side surface of the seventh lens 127. At least one or both of the thirteenth surface S13 and the fourteenth surface S14 of the seventh lens 127 may have a critical point. The thirteenth surface S13 of the seventh lens 127 may have a first critical point P1 from the optical axis OA to the end of the effective area. The first critical point P1 of the thirteenth surface S13 may be located at 55% or more of the effective radius from the optical axis OA, or in the range of 55% to 75%, or in the range of 60% to 70%. The first critical point of the thirteenth surface S13 may be located at a distance of 2.2 mm or more from the optical axis OA, for example, in the range of 2.2 mm to 3.5 mm, or at a distance of 2.5 mm to 3.2 mm. As another example, the thirteenth surface S13 may be set to have no critical point. The thirteenth surface S13 having such a first critical point P1 can refract incident light to the center and the periphery, and can improve aberrations. The first critical point P1 and the second critical point P2 may be points where the sign of the gradient value relative to the optical axis OA and the direction perpendicular to the optical axis OA changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the gradient value is 0. In addition, the first critical point P1 and the second critical point P2 may be points where the slope value of a tangent line passing through the lens surface increases and decreases, or points where it decreases and then increases.

[0436] The fourteenth surface S14 of the seventh lens 127 may have at least one second critical point P2 from the optical axis OA to the end of the effective area. The second critical point P2 of the fourteenth surface S14 may be located at a distance of 60% or more of the effective radius r72 from the optical axis OA, or in a range of 60% to 80%, or in a range of 65% to 75%. The second critical point P2 of the fourteenth surface S14 may be located at a distance of 2.9 mm or more from the optical axis OA, for example, in a range of 2.9 mm to 3.9 mm, or in a range of 3.1 mm to 3.7 mm. Therefore, the second critical point P2 is disposed closer to the edge than the first critical point P1, so that the seventh lens 127 can refract the incident light to the periphery of the image sensor 300.

[0437] The effective radius r51 of the ninth surface S9 of the fifth lens 125 made of a plastic material may be smaller than the curvature radius r31 of the fifth surface S5 of the third lens 123. The effective radius r71 of the fourteenth surface S14 of the seventh lens 127 may be smaller than the effective radius r51 of the ninth surface S9. The average effective radius of the thirteenth surface S13 and the fourteenth surface S14 of the seventh lens 127 is arranged to be smaller than ImgH which is 1 / 2 of the diagonal length of the image sensor 300, so that light can be refracted to the periphery of the image sensor 300 through the fourteenth surface S14 having the second critical point P2.

[0438] A tangent line K3 passing through any point of the ninth surface S9 of the fifth lens 125 and a normal line K4 perpendicular to the tangent line K3 may have a predetermined angle θ2 with the optical axis OA or an axis parallel thereto. The maximum tangent angle θ2 of the ninth surface S14 may be 45 degrees or less, for example, in the range of 5 to 43 degrees or in the range of 13 to 33 degrees. An angle between a normal line perpendicular to a tangent line passing through any point on each of the thirteenth surface S13 and the fourteenth surface S14 of the seventh lens 127 and the optical axis or an axis parallel thereto may be 10 degrees or less. The seventh lens 127 has a low refractive index of less than 1.6, a high Abbe number of 45 or more, and a focal length whose absolute value is set to the maximum, so that incident light can be refracted toward the image sensor 300. Therefore, the seventh lens 127 can compensate for aberrations occurring between plastic lenses and improve aberrations through an aspherical surface. An angle between a normal line perpendicular to a tangent line passing through any point on the eleventh surface S11 of the sixth lens 126 and the optical axis may be 25 degrees or less, and may be greater than angles on the thirteenth and fourteenth surfaces S13 and S14.

[0439] The angle between the normal line perpendicular to the tangent line at any point on the twelfth surface S12 passing through the sixth lens 126 and the optical axis may be 10 degrees or more, for example, in the range of 10 to 43 degrees. Since the sixth lens 126 has a higher refractive index than the fifth lens 125 and the seventh lens 127, and the curvature radius of the twelfth surface S12 is smaller than the curvature radius of the eleventh surface S11, the twelfth surface S12 may refract light incident through the eleventh surface S11 toward the image sensor 300. The difference in curvature radius between the twelfth surface S12 and the eleventh surface S11 may be the largest in the optical system.

[0440] like Fig. 22 and Fig.26 As shown, Sag31 represents the height from the center of the fifth surface S5 of the third lens 123 to the lens surface in the directions X and Y orthogonal to the optical axis OA, and the maximum value of Sag31 may be the height at the edge of the fifth surface S5. Sag32 represents the height from the center of the sixth surface S6 of the third lens 123 to the lens surface in the directions X and Y orthogonal to the optical axis OA, and the maximum value of Sag32 may be the height at the edge of the sixth surface S6. Sag42 represents the height from the center of the eighth surface S8 of the fourth lens 124 to the lens surface in the directions X and Y orthogonal to the optical axis OA, and the maximum value of Sag42 may be the height at the edge of the eighth surface S8. Sag51 represents the height from the center of the ninth surface S9 of the fifth lens 125 to the lens surface in the directions X and Y orthogonal to the optical axis OA, and the maximum value of Sag51 may be the height at the edge of the ninth surface S9. Sag52 (not shown) represents the height from the center of the tenth surface S10 of the fifth lens 125 to the lens surface in the directions X and Y orthogonal to the optical axis OA, and the maximum Sag value is the height at the edge. The maximum Sag value may satisfy the following:

[0441] The following conditions can be met: Max_Sag42 <Max_Sag32<Max_Sag31。

[0442] The following conditions can be met: Max_Sag52 <Max_Sag31<Max_Sag51。

[0443] The difference between Max_Sag42 and Max_Sag52 may be 0.3 or less, and the difference between Max_Sag51 and Max_Sag31 may be 0.5 or less. By setting the Sag value between adjacent glass lenses and plastic lenses, the optical loss between the glass lenses and the plastic lenses may be reduced.

[0444] exist Fig.26In the above, if the Sag value is positive, the lens surface is located on the sensor side based on a straight line orthogonal to the optical axis OA, and if the Sag value is negative, the lens surface is located on the object side based on a straight line orthogonal to the optical axis OA. In addition, when comparing the object-side surface and the sensor-side surface of each lens, the object-side surface and the sensor-side surface of the seventh lens 127 may be surfaces having a minimum difference between a maximum Sag value and a minimum Sag value. This means that the distance between the object-side surface of the seventh lens 127 and the sensor side is constant, and the average value of the radius of curvature may be greater than the average value of the radius of curvature of the other lenses.

[0445] like Fig.21 and Fig. 22 As shown, the center thickness of the first lens 121 to the seventh lens 127 is represented by CT1 to CT7, the edge thickness of the end of the effective area of ​​each lens is represented by ET1 to ET7, the center distance (center gap) between two adjacent lenses is represented by CG1 to CG6, and the edge distance between the edges of each lens is represented by EG1 to EG6. Here, the center thickness of the cemented lens 134 is CT34, and the edge thickness is represented by ET34.

[0446] Fig.23 yes Fig.21 An example of lens data of the optical system of the third embodiment. Fig.23 As shown, the size of the radius of curvature, the thickness of the lens, the center distance between the lenses, the refractive index at the d-line, the Abbe number, and the effective diameter can be set on the optical axis OA of the first lens 121 to the seventh lens 127.

[0447] like Fig.24 As shown, in the lenses of the lens portion 100B of the third embodiment, the lens surfaces of the first lens 121, the fifth lens 125, the sixth lens 126, and the seventh lens 127 may include aspheric surfaces having a 30th order aspheric coefficient. For example, the first lens 121, the fifth lens 125, the sixth lens 126, and the seventh lens 127 may include lens surfaces having a 30th order aspheric coefficient. Fig.25 As shown, the thicknesses T1 to T7 of the first lens 121 to the seventh lens 127 and the distances G1 to G6 between two adjacent lenses can be set, and the thickness T1 to T7 of each lens in the Y-axis direction can be represented at intervals of 0.1 mm or 0.2 mm or more from the optical axis, and the distances G1 to G6 between each lens can be represented at intervals of 0.1 mm or 0.2 mm or more from the optical axis.

[0448] Reference Fig.23 and Fig.25, when comparing the absolute value of the radius of curvature of each lens, the radius of curvature of the eleventh surface S11 of the sixth lens 126 on the optical axis OA may be the largest among the lenses, and the radius of curvature of the ninth surface S9 of the fifth lens 125 may be the smallest among the lenses. The difference between the maximum radius of curvature and the minimum radius of curvature may be 5 times or more, for example, 5 times to 15 times. The difference between the radius of curvature of the object side surface and the sensor side surface of each of the first lens 121 to the fourth lens 124 made of glass may be 40 or less or 30 or less. Therefore, the spherical aberration between the lenses made of glass can be minimized.

[0449] Since the curvature radius of the ninth surface S9 of the fifth lens 125 is arranged to be the smallest, light incident through the glass lens can be refracted toward the area of ​​the image sensor 300. The difference in the curvature radius of the object-side surface and the sensor-side surface of the sixth lens 126 is greater than 40, and can be the largest within the lens portion 100B. The sixth lens 126 can compensate for the aberration occurring between the fifth lens 125 and the seventh lens 127 made of plastic. Here, the curvature radius of each lens is an average value of the radius (absolute value) of the curvature of the object-side surface and the sensor-side surface of each lens.

[0450] When comparing the center thickness of each lens, the center thicknesses CT1, CT2, and CT34 of the first lens 121, the second lens 123, and the cemented lens 134 may be greater than the center thicknesses CT5, CT6, and CT7 of the fifth to seventh lenses 125, 126, and 127. In other words, the center thickness of the plastic material may be greater than the center thickness of the glass lenses spaced apart from each other. Therefore, the weight reduction of the camera module and the optical performance such as aberrations may be improved by the aspherical surface and the thin center thickness of the plastic lens. Here, the center thickness of the fourth lens 124 of the cemented lens 134 may be thinner than the center thickness of the plastic lens.

[0451] The edge thicknesses ET1, ET2, and ET34 of the first lens 121, the second lens 123, and the cemented lens 134 may be greater than the edge thicknesses ET5, ET6, and ET7 of the fifth to seventh lenses 125, 126, and 127. That is, the edge thickness of the plastic material may be greater than the edge thickness of the glass lenses spaced apart from each other. Therefore, the weight reduction of the camera module and the optical performance such as aberrations may be improved by the aspherical surface and thin edge thickness of the plastic lens. Here, the edge thickness of the third lens 124 of the cemented lens 134 may be thinner than the center thickness of the plastic lens.

[0452] The center thickness CT2 of the second lens 122 is the largest among the lenses, and the center thickness CT5 of the fourth lens 124 is the smallest among the lenses. In addition to the cemented lens, any one of the fifth lens 125 and the sixth lens 126 among the lenses may have a minimum center thickness. Among the spaced apart lenses, the maximum center thickness may be at least twice the minimum center thickness, and the difference between the maximum center thickness and the minimum center thickness may be at least 2 mm. That is, even if the plastic material lens provides a thin center thickness, the optical performance may not be reduced, and the thickness of the camera module may be provided to be slim.

[0453] When explaining the center distance CG between the lenses, the center distance CG6 between the sixth lens 126 and the seventh lens 127 is the largest and is greater than the center distance CG1 between the first lens 121 and the second lens 122. The center distance between the fourth lens 124 and the fifth lens 125 may be the smallest. Here, the minimum center distance does not include the bonding surface of the cemented lens 145. The difference between the maximum center distance and the minimum center distance may be 1.5 mm or more, for example, in the range of 1.5 mm to 2.9 mm. In addition, by setting the maximum center distance between the lenses to 70% or less of the maximum center thickness, for example, in the range of 30% to 70%, the thickness of the camera module using a plastic lens with a thin thickness may not be increased without increasing the center distance compared to the center thickness of each lens.

[0454] Regarding the effective diameter, the lens with the largest effective diameter may be arranged between the first lens 121 closest to the object and the seventh lens 127 closest to the image sensor 300. The lens with the largest effective diameter may be a glass lens. The lens with the largest effective diameter may be arranged between the first lens 121 and the plastic lens. The lens with the largest effective diameter may be arranged between the glass lenses and may be, for example, the third lens. Here, the effective diameter is the average of the effective diameters of the object side surface and the sensor side surface of each lens. The lens surface with the largest effective diameter may be the third surface S3 of the third lens 123 or the object side surface of the cemented lens 134. The lens with the smallest effective diameter may be any one of the plastic lenses and may be, for example, the seventh lens adjacent to the image sensor 300. For example, the effective diameter of the seventh lens 127 may be the smallest within the lens portion 100B. The lens surface with the smallest effective diameter may be the thirteenth surface S13 of the seventh lens 127. The effective diameter of each of the lenses made of glass may be greater than the effective diameter of each of the lenses made of plastic. For example, the effective diameter of each of the first to fourth lenses 121 to 124 may be greater than the effective diameters of the fifth, sixth, and seventh lenses 125, 126, and 127. The effective diameters of the first to fourth lenses 121 to 124 may be greater than the diagonal length of the image sensor 300. The average effective diameter of the seventh lens 127 may be less than the diagonal length of the image sensor 300. Therefore, the lens made of plastic may guide light incident through the lens made of glass to the image sensor 300. Here, the average value of the center thickness of the first to seventh lenses 121 to 127 may be greater than the center thickness of each of the plastic lenses, such as the fifth, sixth, and seventh lenses 125, 126, and 127. The average value of the effective diameters of the first to seventh lenses 121 to 127 may be greater than the effective diameter of each of the plastic lenses, such as the fifth, sixth, and seventh lenses 125, 126, and 127.

[0455] Regarding the refractive index, the refractive index of the first lens 121 may be the largest among the lenses and may be greater than 1.7, for example, greater than 1.75. Either or both of the fifth lens 125 and the seventh lens 127 may have the smallest refractive index among the lenses. The difference between the maximum refractive index and the minimum refractive index may be 0.2 or greater. By providing a high refractive index lens made of glass closest to the object and providing a low refractive index lens made of plastic as the lens closest to the glass lens and the lens adjacent to the image sensor 300, the incident efficiency is improved, and the refractive power between the glass lens and the plastic lens may be adjusted to guide light to the image sensor 300. When comparing the Abbe number, the Abbe number of one or both of the second lens 122 and the third lens 123 is the largest among the lenses and may be 57 or greater. The Abbe number of the sixth lens 126 is the smallest among the lenses. The difference between the maximum refractive index and the minimum Abbe number may be 36 or greater. By maximizing the Abbe number of the second lens 122 adjacent to the aperture stop and minimizing the Abbe number of the sixth lens 127 having a low refractive index adjacent to the image sensor 300, the dispersion of light traveling between the glass lenses can be controlled, and the dispersion between the glass lenses and the plastic lenses can be increased to guide the light to the image sensor 300.

[0456] The focal lengths F1, F4, F6, and F7 of the first lens 121, the fourth lens 124, the sixth lens 126, and the seventh lens 127 have negative refractive power, and the focal lengths F2, F3, and F5 of the second lens 122, the third lens 123, and the fifth lens 125 may have positive refractive power. In addition, the fifth lens 125 and the sixth lens 126, which are adjacently arranged lenses, may satisfy the following conditions.

[0457] Condition 1: The refractive index of the lens with positive refractive power is less than the refractive index of the lens with negative refractive power.

[0458] Condition 2: Dispersion of a lens with positive refractive power > dispersion of a lens with negative refractive power

[0459] Here, in the plastic lens, the fifth lens 125 has a positive refractive power, and the sixth lens 126 has a negative refractive power, so according to conditions 1 and 2, the refractive index of the fifth lens is smaller than the refractive index of the sixth lens, and the dispersion value of the fifth lens is greater than the dispersion value of the sixth lens. Chromatic aberration occurring in the plastic lens can be corrected by the plastic lens. In addition, by satisfying that the refractive index difference between the fifth lens 125 and the sixth lens 126 as continuously arranged plastic lenses is 0.1 or more and 0.15 or less and the Abbe number difference is 20 or more and 60 or less, the chromatic aberration occurring in the plastic lens can be compensated by the plastic lens. The optical system generates chromatic aberration and corrects chromatic aberration by using a cemented lens or two lenses arranged in series. As the temperature changes from low to high, the lens shrinks and expands repeatedly. Since the lens characteristics of the lenses of the same material change by the same amount according to the temperature change, it is effective to correct the chromatic aberration between the lenses of the same material even in the case of temperature change.

[0460] In the third embodiment, chromatic aberration occurring in a glass lens is corrected by the third lens 123 and the fourth lens 124 , and chromatic aberration occurring in a plastic lens is corrected by using the fifth lens 125 and the sixth lens 126 .

[0461] The refractive index difference between the third lens 123 and the fourth lens 124 is 0.1 or more and 0.15 or less, and the Abbe number difference satisfies the range of 20 to 60, so that the chromatic aberration occurring in the plastic lens can be compensated by the plastic lens. The refractive index difference is rounded to the third decimal place, and the Abbe number difference is rounded to the first decimal place, and the values ​​are compared. In addition, by arranging a glass lens having a relatively high Abbe number on the object side of the plastic lens, the dispersion of the glass lens can be reduced, and the dispersion of the plastic lens can be increased.

[0462] When comparing focal lengths in absolute values, the focal length of the seventh lens 127 is the largest among the lenses, and may be 55 or greater or 100 or greater. Among the lenses other than the cemented lens 134, the lens having the smallest focal length may be the sixth lens 126. The difference between the maximum focal length and the minimum focal length may be 50 or greater or 80 or greater. Therefore, it is possible to have improved MTF characteristics, aberration control characteristics, resolution characteristics, and the like within the field of view set in the optical system, and to have good optical performance in the periphery of the field of view. The sensor side surface of the seventh lens 127 has a critical point. The critical point is a point at which the trend of the Sag value changes. That is, it is a point at which the Sag value increases and then decreases, or a point at which the Sag value decreases and then increases. Refer to Fig.26, it can be seen that the sensor side surface of the seventh lens 127 has a critical point between the 3.5mm point and the 3.9mm point from the optical axis in the direction perpendicular to the optical axis. The Sag value of the sensor side surface of the seventh lens 127 increases from the optical axis to the 3.5mm point in the direction perpendicular to the optical axis, and then decreases from the 3.5mm point to the 3.9mm point. If the critical point exists on the sensor side surface of the seventh lens 127, that is, on the sensor side surface of the last lens, that is, on the lens surface closest to the sensor, the TTL can be reduced, making it easy to miniaturize and lighten the optical system.

[0463] The thickness T1 of the first lens 121 may have 1 or more times the difference between the maximum thickness and the minimum thickness, for example, 1 to 1.5 times, and the center thickness CT1 may be the smallest, and the edge thickness ET1 may be the largest. The thickness T2 of the second lens 122 may be at least 1.2 times the minimum thickness, for example, in the range of 1.2 to 1.8 times. The second lens 122 may have a maximum center thickness CT2 and a minimum edge thickness ET2. The thickness T3 of the third lens 123 may be at least 1.5 times the minimum thickness, for example, in the range of 1.5 to 2.5 times. The maximum thickness of the fourth lens 124 may be at least 1.2 times the minimum thickness, for example, in the range of 1.2 to 1.8 times, and may be less than the difference between the maximum thickness and the minimum thickness of the third lens 123.

[0464] The center thickness CT34 of the cemented lens 134 may be greater than the edge thickness ET34. The center thickness CT34 of the cemented lens 134 is the distance from the center of the object-side fifth surface S5 of the third lens 123 to the center of the eighth surface S8 of the fourth lens 124, and the edge thickness ET34 is the distance from the end of the effective area of ​​the fifth surface S5 to the eighth surface S8 in the optical axis direction. The maximum thickness of the cemented lens 134 is the center portion, the minimum thickness is the edge portion, and the maximum thickness may be 1 or more times the minimum thickness, for example, in the range of 1 to 1.5 times.

[0465] The maximum thickness of the fifth lens 125 is the central portion, the minimum thickness is the edge portion, and the maximum thickness may be 1.2 times or more of the minimum thickness, for example, in the range of 1.2 times to 1.8 times. The maximum thickness of the sixth lens 126 is at the edge portion, the minimum thickness is at the central portion, and the maximum thickness is at least 1 times the minimum thickness, for example, in the range of 1 times to 1.5 times. The maximum thickness of the seventh lens 127 is at the edge portion, the minimum thickness is at the central portion, and the maximum thickness is at least 1 times the minimum thickness, for example, in the range of 1 times to 1.5 times. The difference between the maximum thickness and the minimum thickness of the fifth lens 125 may be the largest among the lenses except for the cemented lens 134. The difference between the maximum thickness and the minimum thickness of the seventh lens 127 may be the smallest among the lenses. Here, since the difference between the maximum thickness and the minimum thickness of each lens is 2.5 times or less, the TTL may not be increased.

[0466] Among the distances G1 to G6 between the lenses, the first distance G1 between the first lens 121 and the second lens 122 may be the largest at the edge portion and the smallest at the center portion. The second distance G2 between the second lens 122 and the third lens 123 may be the largest at the edge portion and the smallest at the center portion. The fourth distance G4 between the fourth lens 124 and the fifth lens 125 may be the largest at the edge portion and the smallest at the center portion, and the difference between the minimum distance and the maximum distance may be the largest. The fifth distance G5 between the fifth lens 125 and the sixth lens 126 may be the largest at the edge portion and the smallest at the center portion, and the difference between the maximum gap and the minimum gap may be the smallest. The sixth distance G6 between the sixth lens 126 and the seventh lens 127 may be the largest at the center portion and the smallest at the edge portion.

[0467] like Fig. 27 As shown, Fig.21 The CRA in the optical system and the camera module can be 10 degrees or more at the end of the diagonal length of the image sensor, that is, 1.0 field, for example, 10 degrees to 35 degrees or 10 degrees to 25 degrees. In addition, the angle difference of the main light from low temperature (-40 degrees) to high temperature (95 degrees) can be 1 degree or less. Therefore, even if the temperature changes from low temperature to high temperature, the angle difference of the main light will not be large, and stable optical performance can be achieved.

[0468] like Fig.34As shown, the graph showing the ratio of ambient light or relative illuminance according to the image height in the optical system according to the third embodiment shows that the ratio of ambient light is 70% or more, for example, 75% or more, from the center of the image sensor to the end of the diagonal line. That is, it can be seen that there is almost no difference in the ambient illuminance difference (zoom positions 1, 2, 3) according to the room temperature, low temperature, and high temperature until 4.5 mm from the optical axis.

[0469] Figures 28 to 30 It is shown Fig.21 Graphs of diffraction MTF at room temperature, low temperature, and high temperature in an optical system of FIG. 1 and FIG. 2 are graphs showing modulation of illumination according to spatial frequency. Figures 28 to 30 As shown, in the third embodiment of the present invention, the deviation of the MTF based on the room temperature relative to the low temperature or high temperature can be less than 10%, that is, 7% or less.

[0470] Figure 31 to Figure 12 It is shown Fig.21 The aberration characteristics of the optical system at room temperature, low temperature and high temperature are shown in the figure. Figure 31 to Figure 33 From left to right in the aberration graph are the graphs measuring spherical aberration (longitudinal spherical aberration), astigmatism field curve and distortion. Figure 31 to Figure 33 In , the X-axis may represent the focal length (mm) and the degree of distortion (%), and the Y-axis may represent the height of the image. In addition, the graph of spherical aberration is a graph for light in wavelength bands of about 435 nm, about 486 nm, about 546 nm, about 587 nm, and about 656 nm, and the graph of astigmatism and distortion is a graph for light in a wavelength band of about 546 nm. Figure 31 to Figure 33 In the aberration diagram, the closer each curve at room temperature, low temperature, and high temperature is to the Y-axis, the better the aberration correction function can be explained. It can be seen that the optical system 1000 according to the third embodiment has a measurement value close to the Y-axis in almost all areas. That is, the optical system 1000 according to the third embodiment has improved resolution and can have good optical performance not only in the center of the FOV but also in the periphery. Here, the low temperature is -20 degrees or lower, for example, in the range of -20 to -40 degrees, the room temperature is in the range of 22 degrees ±5 degrees or in the range of 18 degrees to 27 degrees, and the high temperature can be in the range of 85 degrees or higher, for example, in the range of 85 degrees to 105 degrees. Therefore, it can be seen that Figure 31 to Figure 33 The decrease in illumination ratio (modulation) from low temperature to high temperature is less than 10%, for example 5% or less, or is almost unchanged.

[0471] Table 4 compares the changes in optical properties such as EFL, BFL, F number F#, TTL and FOV at room temperature, low temperature and high temperature in the optical system according to the third embodiment, and it can be seen that the rate of change of the optical properties at low temperature is 5% or less based on room temperature, for example, 3% or less, and it can be seen that the rate of change of the optical properties at low temperature is 5% or less based on room temperature, for example, 3% or less.

[0472]

Table 4

[0473]

[0474] Therefore, as shown in Table 4, the change rate of the optical characteristics according to the temperature change from low temperature to high temperature, such as the effective focal length (EFL), TTL, BFL, F number, FOV, is 10% or less, that is, 5% or less, for example, in the range of 0 to 5%. This means that even if at least one or two or more plastic lenses are used, temperature compensation for the plastic lenses can be designed to prevent the reliability of optical characteristics from deteriorating. The optical system of the third 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 of the FOV but also at the periphery of the FOV.

[0475] The optical system 1000 according to the third embodiment disclosed above can satisfy at least one or two or more of the mathematical formulas described below. Therefore, the optical system 1000 according to the third embodiment has improved optical characteristics, can effectively control aberration characteristics such as chromatic aberration and distortion aberration, and can have good optical performance not only at the center of the FOV but also at the periphery. The optical system 1000 can have improved resolution. In addition, the thickness of the lens on the optical axis OA described in the formula and the interval between adjacent lenses on the optical axis OA can refer to the third embodiment disclosed above.

[0476] [Formula 1] 0.5 <CT1 / ET1<1

[0477] In Formula 1, by setting the center thickness CT1 and the edge thickness ET1 of the first lens 121, factors affecting the field of view of the optical system can be set, and factors affecting the effective focal length (EFL) can be set, and preferably, it can satisfy: 0.6≤CT1 / ET1<1.

[0478] [Equation 2] 0.2 <CT1 / CA11<0.8

[0479] In Equation 2, the central thickness CT1 of the first lens 121 and the effective diameter CA11 of the object-side surface S1 of the first lens 121 can be set. If this equation is satisfied, deterioration of the strength and optical characteristics of an injection-molded lens made of glass can be prevented. If it is below the range of Equation 1, the lens may be damaged or injection molding may be difficult, and if it is greater than the above range, the TTL may increase and the weight of the optical system may become heavy. Preferably, it can satisfy: 0.3 < CT1 / CA11 < 0.5.

[0480] [Equation 3] Po1 < 0

[0481] In Equation 3, Po1 means the optical power of the first lens 121, and for the performance of the optical system, it can be set to have an effective focal length shorter than the TTL in the optical system.

[0482] [Equation 3-1] F5 * F6 * F7 > 0 and F5 * F7 < 0

[0483] In Equation 3-1, F5, F6, and F7 can be the focal lengths of the fifth lens 125, the sixth lens 126, and the seventh lens 127, and the product of the focal lengths of the plastic lenses can mix negative refractive power and positive refractive power so that they can compensate for each other. Therefore, the aberrations occurring in the plastic lenses can cancel each other out.

[0484] [Equation 4] 1.7 < Nd1 < 2.2

[0485] Equation 4 sets the refractive index of the first lens high so that it can control the factors affecting the reduction of the third-order aberration (Seidel aberration) of the optical system and can reduce the aberration that may occur when the TTL is slightly long. Equation 4 can satisfy: 1.75 < Nd1 < 2.1. If it is designed to be lower than the lower limit of Equation 4, the performance of reducing aberration may be obtained, but since the refractive power of the first lens is weakened, light cannot be effectively collected, so the performance of the optical system will deteriorate. If it is designed to be higher than the upper limit of Equation 4, there is a disadvantage that it becomes difficult to obtain the material. In addition, if the refractive index of the first lens 121 is designed to be lower than the lower limit of Equation 4, in order to increase the refractive power of the first lens and the second lens, the curvature radii of the first lens and the second lens must be increased, and in this case, lens manufacturing becomes more difficult, the lens defect rate increases, and the yield rate will decrease.

[0486] [Equation 4-1] 1.6 ≤ Aver(Nd1:Nd7) ≤ 1.7

[0487] In Formula 4-1, Aver(Nd1:Nd7) is the average of the refractive index values ​​of the d-line of the first to seventh lenses. When the optical system 1000 according to the third embodiment satisfies Formula 4-1, the optical system 1000 can set the resolution and suppress the influence on TTL.

[0488] [Formula 4-2]1 <GLn_Aver / PLn_Aver<1.2

[0489] GLn_Aver is an average value of the refractive index of the lens of the glass material within the lens portion 100B, and PLn_Aver is an average value of the refractive index of the plastic lens. A lens having a high refractive index is located on the object side of the plastic lens, thereby increasing dispersion.

[0490] [Formula 5] 20 <FOV_H<40

[0491] Formula 5 may satisfy: 25≤FOV_H≤35, or a range of 29.2 degrees ±3 degrees, and the length of the image sensor in the horizontal direction is based on 8.064 mm ±0.5 mm. In addition, if Formula 5 is satisfied, when the temperature changes from room temperature to high temperature, the rate of change of the effective focal length and the rate of change of the field of view may be set to 5% or less, for example, 0 to 5%. In addition, even if two or more, for example, three or more plastic lenses are mixed and used in the optical system 1000, degradation of optical characteristics may be prevented by temperature compensation of the plastic lenses.

[0492] [Equation 6] L1R1<0

[0493] If equation 6 is satisfied, the shape of the optical system can be limited. The object-side surface of the first lens 121 is formed in a concave shape so that when it contacts an external structure, surface damage can be prevented and incident light can be refracted in a direction away from the optical axis. Therefore, the gap between the first lens 121 and the second lens 122 can be reduced, or the effective diameter of the second lens 122 can be increased.

[0494] [Formula 6-1] L1R2<0

[0495] [Formula 6-2] L2R1>0, L2R2<0

[0496] Since the first lens 121 has a convex meniscus shape facing the sensor side, it can refract light to the edge of the second lens 122 having a large effective diameter. Additionally, since the second lens has a convex shape on both sides, it can refract light so that the effective diameter of the third lens 123 is not large and the number of lenses can be reduced. Further, since the following condition is satisfied: L2R1 > L2R2, light can be controlled such that the effective diameters of the sensor-side lenses, i.e., the third lens 123 to the seventh lens 127, are not large and the TTL can be reduced. If the following condition is satisfied: L2R1 < L2R2, there are problems such as aberration occurring between the object-side surfaces of the first lens and the second lens, or the effective diameter of the sensor-side lenses increasing, or the TTL increasing.

[0497] [Equation 7] 1 < L7S2_max_sag to Sensor < 3

[0498] In Equation 7, L7S2_max_sag to Sensor can be the straight-line distance from the maximum Sag value of the seventh lens 127 to the image sensor 300, and if this equation is satisfied, the TTL can be reduced and the conditions for manufacturing the imaging device module can be set. Additionally, L7S2_max_sag to Sensor can set the space where the filter 500 and the cover glass 400 located between the image sensor 300 and the seventh lens 127 can be placed. If the range of Equation 7 is less than the lower limit, the space for placing circuit structures such as the filter and the image sensor becomes more restricted, and the process of assembling circuit structures such as the filter and the image sensor into the optical system becomes difficult. When the range of Equation 7 is greater than the upper limit, the process of assembling circuit structures such as the filter and the image sensor into the optical system is easy, but the TTL becomes longer, making it difficult to miniaturize the optical system. That is, Equation 7 can set the minimum distance between the image sensor 300 and the last lens, and preferably satisfies: 1 < L7S2_max_sag to Sensor ≤ BFL. Additionally, when the last lens does not have a point P2 that protrudes more toward the image sensor than the center of the sensor-side surface, the value of Equation 6 can be equal to BFL. BFL is the optical axis distance from the image sensor 300 to the center of the sensor-side surface of the last lens. Specifically, if it can be satisfied: 1.5 < L7S2_max_sag to Sensor < 2.0, the manufacturing convenience and the reduction of the TTL are easier.

[0499] [Equation 8] 1 < CT1 / CT7 < 3

[0500] If Equation 8 is satisfied, the aberration characteristics can be improved, and the influence on the reduction of the optical system can be set. Preferably, Equation 8 can be satisfied: 1 < CT1 / CT7 < 2. In Equation 8, the object-side lens and the sensor-side lens of the optical system can be set as a glass lens and a plastic lens, and the difference in their center thicknesses can be limited. Therefore, the chromatic aberration of the optical system can be improved, good optical performance can be achieved at a set field of view, and the TTL can be controlled.

[0501] [Equation 9] 1 < CT1 / CT6 < 3

[0502] In Equation 9, the center thicknesses CT1 and CT6 of the first lens 121 and the sixth lens 126 can be set. If the optical system satisfies Equation 9, the aberration characteristics can be improved, and the influence on the reduction of the optical system can be set. Preferably, the following condition can be satisfied: 1 < CT1 / CT6 < 2. Equation 9 sets the difference in the center thicknesses of the first lens and the sixth lens, so that the chromatic aberration of the optical system can be improved.

[0503] [Equation 10] 1 < CT34 / CT5 < 5

[0504] In Equation 10, CT34 is the center thickness of the third lens and the fourth lens, for example, the center thickness of the cemented lens 134. When the optical system satisfies Equation 10, the thicknesses of the cemented lens and the adjacent fifth lens 125 can be set, so that the aberration characteristics can be improved, and preferably, it can satisfy: 1 < CT34 / CT5 < 4 or 1.2 < CT34 / CT5 ≤ 3. CT34 can be greater than the center thicknesses CT1 to CT7 of each of the first lens to the seventh lens. Here, the following condition can be satisfied: CT34 > ET34.

[0505] [Equation 11] 0 < L2R1 / L4R2 < 1

[0506] If the optical system 1000 satisfies Equation 11, the optical system 1000 can have improved aberration characteristics.

[0507] [Equation 12] 0 < CT45 - ET45 < 2

[0508] ET45 is the optical axis distance from the end of the effective area of the object-side surface of the fourth lens 124 to the end of the effective area of the sensor-side surface of the fifth lens 125. If the optical system satisfies Equation 12, the center thickness and the edge thickness of the cemented lens can be set to improve the aberration characteristics, and preferably, it can satisfy 1 ≤ CT45 / ET45 < 1.5. ET45 can be greater than the edge thicknesses ET1 to ET7 of each of the first lens to the seventh lens.

[0509] [Equation 13] 0 < CA11 / CA31 < 2

[0510] CA11 means an effective diameter of the first surface S1 of the first lens 121, and CA31 means an effective diameter of the fifth surface S5 of the third lens 123. When satisfying equation 13, the optical system 1000 can control incident light and set factors affecting aberrations, and preferably, 0.5 <CA11 / CA31<1.5。

[0511] [Equation 14] <CA72 / CA42<2

[0512] In Formula 14, CA42 means the effective diameter of the eighth surface S8 of the fourth lens 124, and CA72 means the effective diameter of the fourteenth surface S14 of the seventh lens 127. When Formula 14 is satisfied, the optical system 1000 can control the incident light path and set the factor of performance variation according to CRA and temperature. Preferably, Formula 14 can satisfy: 0.5 <CA72 / CA42<1。

[0513] [Equation 15] <CA12 / CA21<2

[0514] In Formula 15, CA12 means an effective diameter of the second surface S2 of the first lens 121, and CA21 means an effective diameter of the third surface S3 of the second lens 122. When Formula 15 is satisfied, the optical system 1000 can control light traveling toward the first lens group LG1 and the second lens group LG2, and set factors that affect the reduction of lens sensitivity. Formula 15 preferably satisfies: 0.5 <CA12 / CA21<1.5。

[0515] [Equation 16] 0.5 <CA31 / CA42<2

[0516] In Formula 16, CA31 means the effective diameter of the fifth surface S5 of the third lens 123, and CA42 means the effective diameter of the eighth surface S8 of the fourth lens 124. When the optical system 1000 satisfies Formula 16, the size of the cemented lens arranged on the object side of (one or more) plastic lenses can be set. Formula 16 preferably satisfies: 0.8≤CA31 / CA42<1.5.

[0517] [Equation 17] L3R1>L3R2

[0518] Since both sides of the third lens 123 are convex, the effective diameters of the fifth lens 125 to the seventh lens 127 can be reduced, and light can be effectively refracted. Therefore, the effective diameter size of the third lens located closer to the object side than the (one or more) plastic lenses can be set so that the light incident through the cemented lens can be effectively guided to the plastic lens. The effective diameter size is designed to gradually decrease from the fourth lens portion to the sixth lens made of plastic, so that light can be refracted and guided to the sixth lens having a relatively small effective diameter.

[0519] [Equation 17-1] CA4 > CA_PL1

[0520] In Equation 17-1, CA4 is the effective diameter (average effective diameter) of the fourth lens 124, and CA_PL1 can be the effective diameter (average effective diameter) of the plastic lens closer to the object side than the sensor when there are two plastic lenses.

[0521] [Equation 18] 2 < L2R1 / (CA21 / 2) < 5

[0522] When the second lens 122 having two convex surfaces satisfies Equation 18, the optical system 1000 can improve chromatic aberration. When it is less than the lower limit value of Equation 18, the occurrence of aberration on the third surface increases, and when it is greater than the upper limit value, the occurrence of aberration on the third surface decreases, but since the radius of curvature of the fourth surface must be smaller, the occurrence of aberration on the fourth surface increases, and there is a problem of affecting the aberration of the third lens to the seventh lens. Preferably, if the range of 4 < L2R1 / (CA21 / 2) < 5 is satisfied, the radius of curvature of the fourth surface can be designed large while reducing the aberration occurring on the third surface, so that it is easy to manufacture the second lens 122. The aberration occurring in the optical system can be reduced, so that the manufacture of the second lens 122 is easier and the yield is increased.

[0523] [Equation 18-1] CA3 > CA4 > CA5 > CA6

[0524] [Equation 18-2] CA41 > (ImgH * 2)

[0525] [Equation 18-3] CA51 ≥ (ImgH * 2)

[0526] [Equation 18-4] CA71 < (ImgH * 2)

[0527] In Formulas 18-1 to 18-4, CA3, CA4, CA5, and CA6 are the effective diameters (average effective diameters) of the third lens 123 to the sixth lens 126, and ImgH is half of the diagonal length of the image sensor 300. Therefore, the optical path of the region from the third lens 123 to the image sensor 300 can be set by the effective diameter of the sixth lens 126. The fifth lens 125 and the sixth lens 126 are plastic lenses with aspherical surfaces, and the third lens 123 and the fourth lens 124 are glass lenses with curved surfaces, so that the aberrations between the lenses can be compensated for each other. Formula 18 can further satisfy Formula 18-5.

[0528] [Formula 18-5] 1 ≤ Last_GL_CAS1 / Last_GL_CAS2 ≤ 1.4

[0529] In Formula 18-5, Last_GL_CAS1 represents the effective diameter CAS1 of the object-side surface of the last glass lens GL in the optical system, and Last_GL_CAS2 represents the effective diameter CAS2 of the sensor-side surface of the last glass lens GL in the optical system.

[0530] [Formula 19] 1 < CA_GL_AVER / CA_PL_AVER < 1.5

[0531] In Formula 19, CA_GL_AVER represents the average effective diameter of the glass lenses, and CA_PL_AVER represents the average effective diameter of the plastic lenses. In Formula 19, by setting the effective diameter size of the glass lenses and the effective diameter size of the plastic lenses located on the object side compared with the plastic lenses, the path of the incident light can be effectively guided. Formula 19 preferably satisfies: 1.1 < CA_GL_AVER / CA_PL_AVER < 1.4. Here, it can satisfy: nGL > nPL. nGL is the number of lenses made of glass material, and nPL is the number of plastic lenses. In addition, the following condition can be satisfied: nGL - nPL = 0 or 1.

[0532] [Formula 20] 1 ≤ GL_CA1_AVER / PL_CA1_AVER ≤ 1.6

[0533] In Formula 20, GL_CA1_AVER is the average effective diameter of the object side surface of the glass lens, such as the average effective diameter of the object side surface of the first lens to the fourth lens. PL_CA1_AVER is the average effective diameter of the object side surface of the plastic lens, such as the average effective diameter of the object side surface of the fifth lens, the sixth lens, and the seventh lens. Since the effective diameter size of the plastic lens is designed to be relatively small compared to the effective diameter size of the glass lens, Formula 20 can be satisfied. This is because the effective diameter of the sensor side surface of the fifth lens, which is the lens closest to the plastic lens, is designed to be small and has a small radius of curvature, so that light passing through the glass lens can be guided to the effective area of ​​the plastic lens having a relatively small effective diameter. Formula 20 preferably satisfies: 1.1≤GL_CA1_AVER / PL_CA1_AVER≤1.4.

[0534] [Formula 21] CA567 <CA34

[0535] In Formula 21, CA567 means an average effective diameter of the fifth to seventh lenses 125 to 127, and CA34 means an average effective diameter of the third and fourth lenses 123 and 124. When Formula 21 is satisfied, the optical system can guide light to the center and periphery of the image sensor 300 by setting the effective diameter size of the plastic lens disposed between the fourth lens 124 and the image sensor 300 to be smaller than the effective diameters of the third and fourth lenses 123 and 124, thereby improving chromatic aberration.

[0536] [Formula 22] CG2 <CG1<CG6

[0537] In Formula 22, CG1 may be the center distance between the first lens and the second lens, CG2 may be the center distance between the second lens and the third lens, and CG6 may be the center distance between the sixth lens and the seventh lens. If Formula 22 is satisfied, the center distance between glass lenses having a relatively thick thickness may be reduced, thereby reducing TTL and improving optical performance in the peripheral portion of the FOV.

[0538] [Formula 22-1] G3<0.01 or CG3<0.01

[0539] In Formula 22-1, G3 and CG3 can set the distance and center distance between the third lens 123 and the fourth lens 124. If Formula 22-1 is satisfied, the third lens and the fourth lens can be set as a cemented lens. Here, preferably, the following conditions can be satisfied: CT34 <CT2。

[0540] [Formula 23]1 <CT7 / CG6<3

[0541] In Formula 23, CG6 is the center distance or optical axis distance between the sixth lens 126 and the seventh lens 127. In Formula 23, by setting the center thickness CT7 of the seventh lens 127 and the center distance between the sixth lens and the seventh lens, the optical performance in the peripheral part of the field of view can be improved. Formula 23 preferably satisfies: 1.1 <CT7 / CG6<2。

[0542] [Formula 24] (CG5+CG6) <CT34<2(CG5+CG6)

[0543] In Formula 24, CT34 is the center thickness of the cemented lens 134. By arranging the center thickness of the cemented lens to be greater than the sum of the center distance CG5 between the fifth lens and the sixth lens and the center distance CG6 between the sixth lens and the seventh lens, the resolution and chromatic aberration can be improved, and the center distance can be reduced.

[0544] [Formula 25] 4(CG2+CG5) <CT2<8(CG2+CG5)

[0545] In Formula 25, CT2 is the center thickness of the second lens 122, and CG2 is the center distance or optical axis distance between the second lens and the third lens. By arranging the center thickness of the second lens to be greater than 4 times the sum of the center distance CG2 between the second lens and the third lens and the center distance CG5 between the fifth lens and the sixth lens, chromatic aberration can be improved and the center distance can be reduced.

[0546] [Formula 26]1 <CT2 / CT1<4

[0547] In Formula 26, by setting the center thickness CT2 of the second lens to be thicker than the center thickness CT1 of the first lens, factors affecting aberrations can be controlled. Preferably, Formula 26 can satisfy: 1.1 <CT2 / CT1<2。

[0548] [Formula 27]1 <L7R1 / CT7<100

[0549] In Formula 27, L7R1 means the radius of curvature of the thirteenth surface of the seventh lens. In Formula 27, the refractive power of the seventh lens can be controlled by setting the radius of curvature L7R1 of the object-side surface of the seventh lens and the center thickness of the seventh lens. Therefore, good optical performance can be achieved at the center and periphery of the field of view. Preferably, Formula 27 can satisfy: 1 <L7R1 / CT7<30。

[0550] [Equation 28] <L5R2 / L7R1<10

[0551] In Equation 28, L5R2 refers to the radius of curvature of the tenth surface of the fifth lens. In Equation 28, the refractive powers of the fifth lens and the seventh lens can be controlled by setting the radius of curvature of the sensor-side surface of the fifth lens and the object-side surface of the seventh lens. Therefore, good optical performance can be achieved at the center and periphery of the field of view. Preferably, Equation 28 can satisfy: 0 < L5R2 / L7R1 < 1.

[0552] [Equation 29] 0 < L3R1 * L4R2

[0553] In Equation 29, L4R1 is the radius of curvature of the object-side surface of the fourth lens, and L5R2 is the radius of curvature of the sensor-side surface of the fifth lens. If Equation 29 is satisfied, the refractive power of the cemented lens can be controlled to control the optical path incident on the plastic lens. Equation 29 can satisfy: 500 < L4R1 * L5R2.

[0554] [Equation 30] 1 < L6R1 / L5R2 < 10

[0555] In Equation 30, L6R1 is the radius of curvature of the object-side surface of the sixth lens. In Equation 30, by setting the radius of curvature of the sensor-side surface of the fifth lens and the sensor-side surface of the sixth lens, the refractive surface of the plastic lens can be adjusted to refract light effectively toward the image sensor. Equation 30 preferably satisfies: 1 < L6R1 / L5R2 < 6.

[0556] [Equation 31] 1 < L6R2 / L6R1 < 1

[0557] In Equation 31, L6R1 and L6R2 refer to the radius of curvature of the object-side surface and the sensor-side surface of the sixth lens. In Equation 31, by setting the radius of curvature of the object-side surface and the sensor-side surface of the sixth lens, the plastic lens can effectively refract the incident light toward the image sensor. Equation 31 preferably satisfies: 0 < |L6R2 / L6R1| < 0.5. Here, the following conditions can be satisfied: L6R1 > 0, L6R2 > 0, and L6R1 > L6R2.

[0558] [Equation 31-1] 1 < L7R1 / L7R2 < 3

[0559] In Equation 31-1, L7R1 and L7R2 refer to the radius of curvature of the object-side surface and the sensor-side surface of the seventh lens. In Equation 31-1, by setting the radius of curvature of the object-side surface and the sensor-side surface of the seventh lens, light can be refracted through the plastic lens to the image sensor. Equation 31-1 can preferably satisfy: 1 < L7R1 / L7R2 < 2. Here, the following conditions can be satisfied: L7R1 > 0, L7R1 > 0, and L7R2 < L7R1.

[0560] [Equation 32] <CT_Max / CG_Max<5

[0561] In equation 32, the maximum center thickness CT_Max in the lens and the maximum distance CT_Max between adjacent lenses can be set. If equation 32 is satisfied, the optical system can have good optical performance at the focal length at the set field of view, and TTL can be reduced. Preferably, it can satisfy: 1 <CT_Max / CG_Max<3。

[0562] [Equation 33]2<ΣCT / ΣCG<6

[0563] If equation 33 is satisfied, the optical system can have good optical performance at a focal length at a set field of view, and TTL can be reduced. Preferably, it can satisfy: 3<ΣCT / ΣCG<5.

[0564] [Equation 34] 10<ΣNd<30

[0565] If equation 34 is satisfied, the optical system 1000 in which the plastic lens and the glass lens are mixed can control TTL and have improved resolution. In addition, when the number of lenses made of glass material is greater than the number of lenses made of plastic material, and when the number of lenses made of glass material having a relatively thick thickness is greater, the sum of TTL and refractive index can be set. Equation 34 can preferably satisfy: 10<ΣNd<20.

[0566] [Equation 35] 10<ΣAbb / ΣNd<50

[0567] The optical system 1000 may have improved aberration characteristics and resolution when satisfying Formula 35. By setting the sum of the Abbe numbers and the sum of the refractive indices of the lenses in Formula 35, the optical characteristics may be controlled, and preferably, it may satisfy: 10<ΣAbb / ΣNd<40.

[0568] [Equation 36] Distortion < 2

[0569] Distortion means a maximum value or an absolute value of a maximum value in a region from the center (0.0F) to a diagonal end (1.0F) based on optical characteristics detected by the image sensor 300. When the optical system 1000 satisfies Equation 36, the optical system 1000 can improve distortion characteristics and set conditions for image processing. Preferably, distortion ≤ 1 can be satisfied.

[0570] [Equation 37] 0<ΣCT / ΣET<2

[0571] ΣCT is the sum of the center thickness of the lens, and ΣET is the sum of the edge thickness of the effective area of ​​the lens. When equation 37 is satisfied, the optical system can have good optical performance at a focal length at a set field of view, and TTL can be reduced. Equation 37 preferably satisfies: 0.5<ΣCT / ΣET<1.5.

[0572] [Equation 38] 0.5 <CA21 / CA_min<2

[0573] If equation 38 is satisfied, the optical system can control incident light, maintain optical performance, and provide a thinner module. Equation 38 preferably satisfies: 1 <CA21 / CA_min<2。

[0574] [Formula 39]1 <CA_max / CA_min<5

[0575] If equation 39 is satisfied, the optical system can be dimensioned with respect to a slim and compact structure while maintaining optical performance. Equation 39 preferably satisfies: 1 <CA_max / CA_min<2。

[0576] [Formula 40]1 <CA_max / CA_Aver<3

[0577] If equation 40 is satisfied, the optical system can be dimensioned with respect to a slim and compact structure while maintaining optical performance. Equation 40 may preferably satisfy: 1 <CA_max / CA_Aver<1.5。

[0578] [Equation 41] 0.5 <CA_min / CA_Aver<2

[0579] If equation 41 is satisfied, the optical system can be dimensioned with respect to a slim and compact structure while maintaining optical performance. Equation 41 may preferably satisfy: 0.5 <CA_min / CA_Aver<1。

[0580] [Formula 42]1 <CA_max / (2*ImgH)<3

[0581] Formula 42 can be set as the maximum effective diameter CA_Max and length (2*ImgH) of the image sensor, and if it satisfies the formula, the optical system can maintain good optical performance and set the size of a slim and compact structure. Preferably, Formula 42 can satisfy: 1 <CA_max / (2*ImgH)<2。

[0582] [Formula 43]1 <TD / CA_max<4

[0583] TD is the optical axis distance from the center of the object-side surface of the first lens to the center of the sensor-side surface of the last lens. If equation 43 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 43 may preferably satisfy: 2 <TD / CA_max<3。

[0584] [Formula 43-1]TD>SD

[0585] SD is the distance from the position of the aperture stop to the center of the sensor-side surface of the final lens.

[0586] [Formula 44]1 <F / CA51<10

[0587] In equation 44, F means a range of 30 mm or more, for example, 30 mm to 44 mm. Equation 44 sets the relationship between the effective focal length and the effective diameter of the object side surface of the plastic lens so that the effect on the optical system zooming, such as TTL, can be controlled. Equation 44 preferably satisfies: 1 <F / CA61<2。

[0588] [Formula 45]0 <F / |L1R1|<2

[0589] In Formula 45, the effective focal length of the optical system and the radius of curvature of the object-side surface of the first lens can be set so that the influence on the incident light and TTL can be controlled. Formula 45 preferably satisfies: 0.5≤F / |L1R1|<1.

[0590] [Equation 46]Max_th / Min_th<5

[0591] In Equation 46, Max_th is the thickness of the thickest region of the lens, and Min_th is the thickness of the thinnest region of the lens. Max_th / Min_th is the ratio of the thickest thickness to the thinnest thickness of each lens. The thickest thickness Max_th of the lens can be the center thickness CT of the lens, and the thinnest thickness Min_th of the lens can be the edge thickness ET of the lens, but the reverse is also possible. The thickest thickness Max_th of the lens can be the edge thickness ET of the lens, and the thinnest thickness Min_th of the lens can be the center thickness CT of the lens. The edge thickness ET means the thickness at the end of the effective diameter. When Equation 46 is satisfied, the optical system can control the influence on the effective focal length. Preferably, the following condition can be satisfied: 3.5 < Max_th / Min_th ≤ 4.5. Here, the ratio of the maximum thickness to the minimum thickness of the plastic lens can satisfy the following condition. Max_PL_th is the thickness value of the thickest region of the plastic lens, and Min_PL_th is the thickness value of the thinnest region of the plastic lens. Max_PL_th can be the center thickness CT of the plastic lens, and Min_PL_th can be the edge thickness ET of the plastic lens. The edge thickness ET means the thickness at the end of the effective diameter. The reverse is also possible. Max_PL_th can be the edge thickness ET of the plastic lens, and Min_PL_th can be the center thickness CT of the plastic lens. The edge thickness ET means the thickness at the end of the effective diameter.

[0592] Condition 1: 1.0 < Max_PL_th / Min_PL_th < 2.5

[0593] If it is less than the lower limit of Condition 1 above, it is difficult to manufacture the plastic lens. That is, it is manufactured by injecting a high-temperature resin and hardening it at a low temperature, but if the thickness difference is large, the lens may shrink unevenly when cooled at a low temperature, which may result in a high surface defect rate. In addition, if it is greater than the range of Condition 1, the plastic lens shrinks and expands as the temperature changes from -40 degrees to 105 degrees, and during this process, the rate of change of the lens shape becomes significantly apparent, which may deteriorate the performance of the optical system. Preferably, the following condition can be satisfied: 1.5 < Max_PL_th / Min_PL_th < 2.3 or 1.7 < Max_PL_th / Min_PL_th < 2.2.

[0594] [Equation 46-1] 3 < Max(EG / CG) < 20

[0595] In formula 46-1, Max (EG / CG) can set the ratio of the center distance CG to the edge distance EG between adjacent lenses to the maximum value. If formula 46-1 is satisfied, the optical system can adjust the impact on the effective focal length. Preferably, the following conditions can be satisfied: 5 <Max(EG / CG)≤15。

[0596] [Formula 46-2]1 <Min(CT / ET)<1.5

[0597] Min(CT / ET) can set the ratio of the center thickness CT to the edge thickness ET of each lens to the minimum value. If equation 46-2 is satisfied, the optical system can adjust the effect on the effective focal length. Preferably, the following conditions can be satisfied: 1 <Min(CT / ET)≤1.2。

[0598] [Formula 46-3]1 <Min(EG / CG)<2

[0599] In formula 46-3, Min (EG / CG) can set the ratio of the center distance CG to the edge distance EG between adjacent lenses to the minimum value. If formula 46-2 is satisfied, the optical system can adjust the impact on the effective focal length. Preferably, it can satisfy: 1 <Min(EG / CG)≤1.7。

[0600] [Formula 47]0 <EPD / |L1R1|<1

[0601] EPD means the size of the entrance pupil diameter of the optical system 1000 (mm), and L1R1 means the radius of curvature of the first surface S1 of the first lens (mm). When the optical system 1000 according to the third embodiment satisfies Equation 47, the optical system 1000 can control the incident light. Preferably, the following conditions can be satisfied: 0.3 <EPD / |L1R1|≤0.9。

[0602] [Formula 48]-5 <F1 / F3<0

[0603] If Equation 48 is satisfied, the resolution can be improved by controlling the refractive powers of the first lens and the third lens, and the TTL and the effective focal length (EFL) can be affected.

[0604] [Formula 48-1]|F3| <F4<F5

[0605] [Formula 48-2]F5>|F6|

[0606] [Formula 48-3]2*F5<|F7|

[0607] In Formula 48-1 to Formula 48-3, F5 is the focal length of the fifth lens, F4 is the focal length of the fourth lens, F6 is the focal length of the sixth lens, and F7 is the focal length of the seventh lens. Therefore, the focal lengths of the third lens and the fourth lens adjacent to the plastic lens can be smaller than the focal lengths of the fifth lens and the seventh lens. Therefore, the refractive power of the last glass lens can be controlled to guide light to the effective area of ​​the plastic lens. Here, F1 is -39 mm or less, for example, in the range of -39 mm to -59 mm. F2 is 17 mm or more, for example, in the range of 17 mm to 26 mm. F3 is 15 mm or more, for example, in the range of 15 mm to 24 mm. F4 is -19 mm or less, for example, in the range of -19 mm to -29 mm. F5 is 31 mm or more, for example, in the range of 31 mm to 46 mm. F6 is -16 mm or less, for example, in the range of -16 mm to -25 mm. F7 is -111 mm or less, for example, in the range of -111 mm to -167 mm. The sum of the focal lengths of the second lens, the fourth lens, the fifth lens, and the sixth lens can be set to 12 mm or more, for example, in the range of 12 mm to 18 mm. The balance of the respective focal lengths of the second lens, the fourth lens, the fifth lens, and the sixth lens can suppress the difference in the point position due to temperature changes. Therefore, it is possible to suppress the degradation of the optical characteristics of the imaging lens due to temperature changes.

[0608] The aperture stop is arranged on the object side of the second lens 122. The focal length of the lens arranged on the sensor side closer to the aperture stop than the aperture stop is greater than 0. In the third embodiment of the present invention, the focal length F2 of the second lens 122 should be designed to be greater than 0. In this case, the second lens 122 collects light so that the effective diameter of the third lens to the seventh lens, which are lenses arranged closer to the sensor than the second lens 122, can be prevented from increasing. In addition, since the TTL can be prevented from becoming longer, miniaturization of the optical system is possible. The composite focal length of the lens arranged on the sensor side closer to the sensor than the aperture stop, that is, the lens arranged closer to the sensor than the aperture stop, is designed to be greater than 0. In the third embodiment of the present invention, the composite focal length of the third lens to the seventh lens is designed to be greater than 0. In this case, the optical system can be miniaturized by reducing the TTL at the horizontal field of view FOV_H of 25 degrees to 35 degrees.

[0609] [Equation 49]Po3*Po4<0

[0610] Po3 is the power value of the third lens, and Po4 is the power value of the fourth lens. That is, the power of the third lens and the fourth lens have power of opposite signs, so that aberration can be improved and light can be effectively guided through the plastic lens. When the following condition is satisfied: Po3*Po4>0, the effect of improving chromatic aberration in the cemented lens is not significant.

[0611] [Formula 49-1]Po1(Po3*Po4)>0

[0612] [Formula 49-2] F34>0

[0613] [Formula 49-3] F5*F6*F7>0

[0614] [Formula 49-4] F5*F6<0

[0615] Po1 is the power value of the first lens, F34 is the composite focal length of the third lens and the fourth lens, and F5, F6, and F7 are the focal lengths of the sixth lens, the seventh lens, and the eighth lens. If Formula 49-1 to Formula 49-4 are satisfied, it is easy to improve the aberration of the optical system having the fourth lens and the fifth lens as a cemented lens, and the incident light can be effectively guided to the plastic lens.

[0616] [Formula 50] 15 <Vd4-Vd5<50

[0617] In Formula 50, Vd4 is the Abbe number of the fourth lens, and Vd5 is the Abbe number of the fifth lens. If Formula 50 is satisfied, the difference dimension of the Abbe numbers of at least two lenses forming the cemented lens can be maintained at a certain value or more, and chromatic aberration can be improved. Formula 50 preferably satisfies: 20≤Vd4-Vd5≤40. If the cemented lens is smaller than the lower limit of Formula 50, it may not be significant in improving the aberration characteristics of the optical system. Therefore, if the difference in the Abbe numbers between the object side lens and the sensor side lens in the cemented lens is 20 or more and 40 or less, the aberration characteristics can be improved.

[0618] [Formula 50-1]Vd6<Vd5、F6*Vd6> F5*Vd5、Vd6<Vd7、|F7*Vd7|> |F6*Vd6|、Vd7<Vd2、|F7*Vd7|> F2*Vd2、Vd5<Vd3、F5*Vd5> F3*Vd3

[0619] In Formula 50-1, Vd2, Vd3, Vd5, Vd6, Vd7 are the Abbe numbers of the second lens, the third lens, the fifth lens, the sixth lens, and the seventh lens, and F2, F3, F5, F6, F7 are the focal lengths of the second lens, the third lens, the fifth lens, the sixth lens, and the seventh lens. Therefore, aberration correction can be performed between the plastic lens and the glass lens.

[0620] [Equation 51] 0<|F1| / F<10

[0621] Formula 51 sets the relationship between the focal length F1 of the first lens and the effective focal length F, so that the TTL of the optical system can be set. Preferably, Formula 51 can satisfy: 1<|F1| / F<5.

[0622] [Equation 52] 0<|F4 / F5|<1

[0623] In Formula 52, the relationship between the focal lengths F4 and F5 of the fourth lens and the fifth lens can be set so that the refractive power and the optical path of the last glass lens and the first plastic lens adjacent thereto can be adjusted, and the resolution can be improved. Formula 52 can preferably satisfy: 0.5<|F4 / F5|<0.9.

[0624] [Equation 53] 0<|F4 / F7|<1

[0625] In Formula 53, by setting the relationship between the focal lengths F4 and F7 of the fourth lens and the seventh lens, the refractive power and the optical path of the last glass lens and the last plastic lens can be adjusted, and the resolution can be improved. Formula 53 preferably satisfies: 0<|F4 / F7|<0.6.

[0626] [Equation 54] 0<|F6 / F1|<1.2

[0627] In Formula 54, by setting the relationship between the focal lengths F1 and F6 of the first lens and the sixth lens, the refractive power and the optical path of the first glass lens and the first plastic lens can be adjusted, the influence of TTL can be adjusted, and the resolution can be improved. Formula 54 preferably satisfies: 0.1<|F6 / F1|<0.6.

[0628] [Equation 55] 0<|F27| / F<2

[0629] In Formula 55, the relationship between the composite focal length F27 of the second to seventh lenses and the effective focal length F is set so that the refractive power of the second to seventh lenses can be controlled to improve the resolution, and the optical system can be set in a slim and compact size. Formula 55 preferably satisfies: 0.5<|F27 / F|<1.5.

[0630] [Equation 56] 0<|F27 <F6|<1

[0631] In Formula 56, the relationship between the composite focal length F27 of the second to seventh lenses and the focal length F6 of the sixth lens is set so that the composite refractive power of the second to seventh lenses and the refractive power of the plastic lens can be controlled to improve the resolution, and the optical system can be set in a slim and compact size. Formula 56 preferably satisfies: 0<|F27 <F6|<0.8。

[0632] [Equation 57] 0<|F27 <F7|<1

[0633] In Formula 57, the relationship between the composite focal length F27 of the second to seventh lenses and the focal length F7 of the seventh lens is set so that the refractive power of the second to seventh lenses and the refractive power of the last plastic lens can be adjusted to improve the resolution, and the optical system can be set in a slim and compact size. Formula 57 preferably satisfies: 0<|F27 <F7|<0.5。

[0634] [Equation 58] <F6 / F<5

[0635] In Formula 58, the relationship between the focal length F6 of the sixth lens and the effective focal length F is set so that the refractive power of the first plastic lens and the entire focal length can be adjusted to improve the resolution, and the optical system can be set in a slim and compact size. Formula 58 preferably satisfies: 1 <F6 / F<4。

[0636] [Equation 59] F_LG1 / F_LG2<0

[0637] In Formula 59, a relationship between the focal length F_LG1 of the first lens group LG1 and the focal length F_LG2 of the second lens group may be set. The focal length of the first lens group may have a negative value, and the focal length of the second lens group may have a positive value. When Formula 59 is satisfied, the optical system 1000 may improve aberration characteristics such as chromatic aberration and distortion aberration. Formula 59 may preferably satisfy: 2<|F_LG1 / F_LG2|<7.

[0638] [Formula 60]1 <nGL / nPL<4

[0639] In Formula 60, nGL means the number of lenses made of glass, and nPL means the number of lenses made of plastic. In Formula 60, by arranging the number of plastic lenses to be greater than 1 times the number of glass lenses, the thickness of the optical system can be reduced, and a wider range of refractive power can be provided by the aspherical surface. Formula 60 preferably satisfies: 1 <nGL / nPL<2。

[0640] [Equation 61] CA7≤CA1 <CA3

[0641] In Formula 61, the size relationship of the average effective diameters CA1, CA3, and CA7 of the object side surface and the sensor side surface of the first lens, the third lens, and the seventh lens can be set. When Formula 61 is satisfied, the first lens group and the second lens group can be set, and the aberration can be improved by the first lens of the second lens group LG2. CA3 can have the largest effective diameter in the optical system.

[0642] [Equation 62] 0 < ΣPL_CT / ΣGL_CT < 1

[0643] In Equation 62, ΣPL_CT is the sum of the center thicknesses of the plastic lens(es), and ΣGL_CT is the sum of the center thicknesses of the glass lenses. If Equation 62 is satisfied, the total TTL can be controlled by setting the relationship between the thickness of the plastic lens and the thickness of the glass lens with respect to TTL. Equation 62 is preferably satisfied as: 0.3 < ΣPL_CT / ΣGL_CT < 0.8.

[0644] [Equation 63] 0 < ΣPL_Nd / ΣGL_Nd < 1.2

[0645] In Equation 63, ΣPL_Nd is the sum of the refractive index thicknesses of the plastic lens(es) at the d-line, and ΣGL_Nd is the sum of the refractive indices of the glass lenses at the d-line. If Equation 63 is satisfied, the refractive index relationship between the plastic lens and the glass lens can be set to control the overall resolution. Preferably, Equation 63 can be satisfied as: 0.5 < ΣPL_Nd / ΣGL_Nd < 1.

[0646] [Equation 64] 10 mm < TTL < 45 mm

[0647] TTL means the distance (mm) on the optical axis OA from the center of the first surface S1 of the first lens 121 to the image surface of the image sensor 300. In Equation 64, TTL can be set to be more than 10 mm or 20 mm, thereby providing an optical system for a vehicle. Equation 64 can preferably satisfy the following conditions: 30 mm < TTL ≤ 40 mm or TD < TTL.

[0648] [Equation 65] 2 mm < ImgH < 20 mm

[0649] Equation 65 can set the diagonal size (2 * ImgH) of the image sensor 300, and can provide an optical system with a sensor size for a vehicle. Equation 65 can preferably be satisfied as: 4 mm ≤ ImgH < 6 mm.

[0650] [Equation 66] 1 mm < BFL < 3.5 mm

[0651] In Formula 66, BFL is set to be greater than 1 mm and less than 3.5 mm, so that the installation space of the filter 500 and the cover glass 400 can be ensured, and the assembly of the components can be improved by the distance between the image sensor 300 and the last lens, and the bonding reliability can be improved. Formula 66 preferably satisfies: 1.5 mm ≤ BFL ≤ 3 mm. When BFL is less than the range of Formula 68, some of the light traveling to the image sensor may not be transmitted to the image sensor, which may be the cause of reduced resolution. When BFL exceeds the range of Formula 68, stray light may be introduced, which may deteriorate the aberration characteristics of the optical system.

[0652] [Formula 67]3 <BFL / CG5<10

[0653] In Formula 67, BFL is set to be greater than the distance between lenses, for example, the center distance CG5 between the fifth lens and the sixth lens, so that the installation space for the filter 500 and the cover glass 400 can be ensured, and the assembly of the components can be improved and the bonding reliability can be improved by the distance between the image sensor 300 and the last lens. Formula 67 can satisfy: 5≤BFL / CG5≤9.

[0654] [Formula 68] CG2, CG4, CG5 <BFL

[0655] In Formula 68, BFL is set to be greater than the distance between lenses, such as the center distance CG2 between the second lens and the third lens, the center distance CG4 between the fourth lens and the fifth lens, and the center distance CG5 between the fifth lens and the sixth lens, so that the installation space for the filter 500 and the cover glass 400 can be ensured, and the assembly of the components can be improved and the bonding reliability can be improved by the distance between the image sensor 300 and the last lens. In addition, the seventh lens as the last lens can disperse the incident light to the effective area of ​​the image sensor, but if BFL does not satisfy Formula 68, some of the emitted light may not be transmitted to the effective area of ​​the image sensor, thereby reducing the resolution. Here, CG2 can be the optical axis distance between the lens located on the object side and the cemented lens, and can be smaller than BFL.

[0656] [Type 69] 3mm <F<40mm

[0657] Formula 69 can set the total focal length F to adapt to the vehicle optical system. Formula 69 can satisfy: 5mm <F<30mm。

[0658] [Equation 70] FOV < 45 degrees

[0659] In Formula 70, FOV means the field of view (degrees) of the optical system 1000, and a vehicle optical system of less than 45 degrees may be provided. Preferably, FOV may satisfy: 20 degrees ≤ FOV ≤ 40 degrees.

[0660] [Formula 71]1 <TTL / CA_max<5

[0661] In Formula 71, CA_max means the maximum effective diameter (mm) among the object-side surface and the sensor-side surface of the plurality of lenses, and TTL means the distance (mm) from the vertex of the first surface S1 of the first lens to the image surface of the image sensor 300 on the optical axis OA. Formula 71 sets the relationship between the total optical axis length of the optical system and the maximum effective diameter, thereby providing an improved vehicle optical system. Formula 71 may preferably satisfy: 1.5 <TTL / CA_max≤4。

[0662] [Formula 72]2 <TTL / ImgH<10

[0663] Equation 72 may set the total optical axis length TTL of the optical system and the diagonal length ImgH of the image sensor 300 from the optical axis. When the optical system 1000 according to the third embodiment satisfies Equation 72, the optical system 1000 may have a TTL for application to the vehicle image sensor 300, thereby providing a more improved image quality. Equation 72 may preferably satisfy: 4 <TTL / ImgH<10。

[0664] [Equation 73] 0.1 <BFL / ImgH<1

[0665] Formula 73 can set the optical axis distance between the image sensor 300 and the last lens and the length of the image sensor 300 in the diagonal direction from the optical axis. When the optical system 1000 according to the third embodiment satisfies Formula 73, the optical system 1000 can ensure the BFL of the size of the image sensor 300 for the application vehicle, set the distance between the last lens and the image sensor 300, and have good optical characteristics at the center and periphery of the FOV. Formula 73 can preferably satisfy: 0.2 <BFL / ImgH<0.8。

[0666] [Formula 74]5 <TTL / BFL<30

[0667] Equation 74 may set the total optical axis length TTL of the optical system and the optical axis distance BFL between the image sensor 300 and the last lens (unit: mm). When the optical system 1000 according to the third embodiment satisfies Equation 55, the optical system 1000 may ensure BFL. Equation 74 may preferably satisfy: 10 <TTL / BFL<25。

[0668] [Formula 75]1 <TTL / F<3

[0669] Formula 75 can set the total focal length F and the total optical axis length TTL of the optical system 1000. Therefore, an optical system for a driver assistance system can be provided. Formula 75 can preferably satisfy: 1.5≤TTL / F≤2.8 or 2≤TTL / F≤2.8. When the optical system 1000 according to the third embodiment satisfies Formula 75, the optical system 1000 can have an appropriate focal length within the set TTL range, and provide an optical system that can maintain an appropriate focal length and form an image even when the temperature changes from a low temperature to a high temperature. If it is lower than the lower limit of Formula 75, it is necessary to increase the refractive power of the lens, making it difficult to correct spherical aberration or distortion aberration. If it is higher than the upper limit of Formula 75, the effective diameter or TTL of the lens becomes longer, which may lead to the problem of a larger imaging lens system.

[0670] [Formula 76]3 <F / BFL<10

[0671] Formula 76 can set the total focal length F of the optical system 1000 and the optical axis distance BFL between the image sensor 300 and the last lens. When the optical system 1000 according to the third embodiment satisfies Formula 76, the optical system 1000 can have a set field of view and an appropriate focal length, and a vehicle optical system can be provided. In addition, the optical system 1000 can minimize the gap between the last lens and the image sensor 300, and thus can have good optical characteristics in the periphery of the FOV. Formula 76 can preferably satisfy: 5 <F / BFL<10。

[0672] [Formula 77]1 <F / ImgH<5

[0673] Equation 77 may set the total focal length F (mm) of the optical system 1000 and the diagonal length ImgH of the image sensor 300 from the optical axis. The optical system 1000 may have improved aberration characteristics in the size of the vehicle image sensor 300. Equation 77 may preferably satisfy: 2 <F / ImgH<4。

[0674] [Formula 78]1 <F / EPD<5

[0675] Equation 78 can set the total focal length F (mm) and the entrance pupil diameter of the optical system 1000. Therefore, the overall brightness of the optical system can be controlled. Equation 78 can preferably satisfy: 1 <F / EPD<3。

[0676] [Formula 79]0 <BFL / TD<0.3

[0677] Equation 79 can set the relationship between the optical axis distance TD of the lens of the optical system 1000 and the back focal length BFL. Therefore, the resolution of the optical system can be maintained and the overall size can be controlled. Equation 79 preferably satisfies: 0 < BFL / TD < 0.2. When the conditional value of BFL / TD is 0.2 or more, BFL is designed to be larger than TD, so that the size of the entire optical system becomes larger, making it difficult to miniaturize the optical system, and the distance between the seventh lens and the image sensor becomes longer, so that the unnecessary amount of light between the seventh lens and the image sensor may increase, resulting in problems of reduced resolution such as deterioration of aberration characteristics.

[0678] [Equation 80] 0 < EPD / ImgH / FOV < 0.2

[0679] Equation 80 can set the relationship between the entrance pupil diameter (EPD), the length of half of the maximum diagonal length ImgH of the image sensor, and the field of view. Therefore, the overall size and brightness of the optical system can be controlled. Preferably, Equation 80 can satisfy: 0 < EPD / ImgH / FOV < 0.1.

[0680] [Equation 81] 5 < FOV / F# < 40

[0681] Equation 81 can set the relationship between the field of view of the optical system and the F-number F#. Preferably, Equation 81 can satisfy: 10 < FOV / F# < 30. At this time, F# is set to 1.6 or less to provide a bright image.

[0682] [Equation 82] 1 < ΣGL_CT / F# < 20

[0683] Equation 82 can set the relationship between the sum ΣGL_CT of the center thicknesses of the glass lenses of the optical system and the F-number F#. Preferably, Equation 82 can satisfy: 5 < ΣGL_CT / F# < 15.

[0684] [Equation 83] 1 < ΣPL_CT / F# < 20

[0685] Equation 83 can set the relationship between the sum ΣPL_CT of the center thicknesses of the plastic lenses of the optical system and the F-number (F#). Preferably, Equation 83 can satisfy: 1 < ΣPL_CT / F# < 10.

[0686] [Equation 84] 1 ≤ ΣGL_Nd / F# < 2

[0687] Equation 84 can set the relationship between the sum ΣGL_Nd of the refractive indices of the glass lenses of the optical system and the F-number F#. Equation 84 preferably satisfies: 1 ≤ ΣGL_Nd / F# < 1.5.

[0688] [Equation 85] 0 < ΣPL_Nd / F# < 5

[0689] The relationship between the sum of the refractive indices ΣPL_Nd of the plastic lenses of the optical system and the F number F# can be set in equation 85. Equation 85 preferably satisfies: 0<ΣPL_Nd / F#<1.5.

[0690] [Formula 86] CT34*L3R1 <CT2*L2R1

[0691] In Formula 87, the product of the center thickness CT2 of the second lens 122 and the curvature radius L2R1 of the object side surface is set to be greater than the product of the center thickness CT34 of the cemented lens 134 and the curvature radius L3R1 of the object side surface, so that the optical properties of the glass lens between the first lens 121 and the cemented lens 134 can be set.

[0692] [Formula 87] CT34*L3R1 <CT34*L4R2

[0693] In Formula 61, the relationship between the curvature radius L3R1 of the object side surface of the center thickness CT34 of the cemented lens 134 and the curvature radius L3R2 of the sensor side surface can be set so that the axial chromatic aberration can be reduced and the gap between the lenses can be removed to reduce TTL.

[0694] [Equation 88] 2(CT5*L5R1)<(CT34*L3R1)<4(CT5*L5R1)

[0695] In Formula 88, the curvature radius L3R1 of the object side surface of the cemented lens 134 and the center thickness CT5 and the curvature radius L5R1 of the object side surface of the plastic lens adjacent to the cemented lens are set so that the aberration difference between the adjacent glass lens and the plastic lens can be compensated.

[0696] [Equation 89] (CT7*L7R1)<(CT2*L2R1)<3(CT7*L7R1)

[0697] In Formula 89, the relationship between the curvature radius L2R1 of the second lens 122 having the maximum center thickness and the last plastic lens can be set so that the aberration difference between the glass lens and the plastic lens can be compensated.

[0698] [Equation 90] 200 < (TTL * ΣGL_Nd) < 300

[0699] In Equation 90, by setting the relationship between TTL and the sum of the refractive indexes of the glass material, the occurrence of spherical aberration due to the glass material can be controlled.

[0700] [Equation 91] 150 < (TTL * ΣPL_Nd) < 200

[0701] In Equation 91, by setting the relationship between TTL and the sum of the refractive index of the plastic material, the spherical aberration caused by the glass material can be corrected by the plastic material.

[0702] [Formula 92]0.05<|Sag_i / (CA_i / 2)|<0.2(i=S1, S2, S3, S4)

[0703] Formula 92 can set the relationship between the Sag values ​​of the first to fourth surfaces S1, S2, S3 and S4 of the first lens and the second lens and the effective diameter CA, and if the formula is satisfied, the refractive power of the lens can be improved. Here, if Formula 92 further satisfies the following condition: Nd1>1.7, the first lens and the second lens can focus light with sufficient optical power without sharply designing the curvature radius of the first lens and the second lens within the effective diameter.

[0704] [Formula 93]

[0705]

[0706] In Formula 93, Z may mean the distance from any position on the aspherical surface to the vertex of the aspherical surface in the direction of the optical axis. Y may mean the distance from any position on the aspherical surface to the optical axis in the direction perpendicular to the optical axis. C may mean the curvature of the lens, and K may mean the cone constant. In addition, A, B, C, D, E, and F may mean aspherical coefficients.

[0707] The optical system 1000 according to the third embodiment may satisfy at least one or two or more of equations 1 to 50. In this case, the optical system 1000 may have improved optical characteristics and improved resolution, and may improve aberration characteristics and distortion characteristics. In addition, the optical system 1000 may ensure a BFL for applying the vehicle image sensor 300, compensate for degradation of optical characteristics due to temperature changes, and minimize the gap between the last lens and the image sensor 300, thereby providing good optical performance at the center and periphery of the FOV.

[0708] Table 5 shows the terms of the above formula in the optical system 1000 of the third embodiment, including TTL (mm), BFL, effective focal length F (mm), ImgH (mm), effective diameter CA (mm), thickness (mm), TD (mm) which is the optical axis distance from the first surface S1 to the fourteenth surface S14, focal length F1 to F7 (mm) of each of the first lens to the seventh lens, the sum of refractive indices, the sum of Abbe numbers, the sum of thicknesses (mm), the sum of distances between adjacent lenses, effective diameter characteristics, the sum of refractive indices of glass lenses, the sum of refractive indices of plastic materials, FOV (degrees), edge thickness ET, focal lengths of the first lens group and the second lens group, and F-number, etc. of the optical system 1000.

[0709]

Table 5

[0710]

[0711]

[0712] Table 6 shows the result values ​​of the above-mentioned formulas 1 to 50 in the optical system 1000 of the third embodiment. Referring to Table 5, it can be seen that the optical system 1000 satisfies at least one, two or more, or three or more of the formulas 1 to 50. Therefore, the optical system 1000 can have good optical performance and excellent optical characteristics at the center and periphery of the FOV.

[0713]

Table 6

[0714]

[0715]

[0716]

[0717] Table 7 shows the result values ​​of the above-mentioned equations 51 to 91 in the optical system 1000 of the third embodiment. Referring to Table 6, it can be seen that the optical system 1000 satisfies at least one, two or more, or three or more of equations 51 to 92. Therefore, the optical system 1000 can have good optical performance and excellent optical characteristics at the center and periphery of the FOV.

[0718]

Table 7

[0719]

[0720]

[0721]

[0722] Fig.352 is an example of a plan view of a vehicle to which a camera module or an optical system according to an embodiment of the present invention is applied. Fig.35 , the vehicle camera system according to an embodiment of the present invention includes an image generating unit 11, a first information generating unit 12, second information generating units 21, 22, 23, 24, 25 and 26, and a control unit 14. The image generating unit 11 may include at least one camera module 31 disposed in the vehicle, and may capture an image in front of the vehicle and / or the driver to generate an image in front of or inside the vehicle. The image generating unit 11 may use the camera module 31 to capture images in front of the vehicle and around the vehicle in one or more directions to generate an image around the vehicle. Here, the front image and the surrounding image may be digital images, and may include color images, black and white images, and infrared images. In addition, the front image and the surrounding image may include still images and moving images. The image generating unit 11 provides the driver image, the front image, and the surrounding image to the control unit 14. Next, the first information generating unit 12 may include at least one radar and / or camera placed in the vehicle, and detects the front of the vehicle to generate first detection information. Specifically, the first information generating unit 12 is placed in the host vehicle, and detects the position and speed of a vehicle located in front of the host vehicle, the presence and position of a pedestrian, and the like to generate first detection information.

[0723] Using the first detection information generated by the first information generating unit 12, the distance between the vehicle and the vehicle in front can be controlled to be maintained at a certain level, and the stability of the vehicle operation can be improved in a pre-set specific situation such as when the driver wants to change the driving lane of the vehicle or when reversing and parking. The first information generating unit 12 provides the first detection information to the control unit 14. The second information generating units 21, 22, 23, 24, 25 and 26 detect each side of the vehicle based on the front image generated by the image generating unit 11 and the first detection information generated by the first information generating unit 12 to generate the second detection information. Specifically, the second information generating units 21, 22, 23, 24, 25 and 26 may include at least one radar and / or camera device arranged on the vehicle, and may detect the position and speed of the vehicle located on the side of the vehicle, or take an image. Here, the second information generating units 21, 22, 23, 24, 25 and 26 may be arranged on each of the front corners, side mirrors, and rear center and rear corners of the vehicle.

[0724] At least one information generating unit of these vehicle camera systems may be equipped with the optical system d...

Claims

1. An optical system, comprising: Image sensor; as well as first to fourth lenses, the first to fourth lenses being aligned along an optical axis from an object toward the image sensor, Wherein, the optical power of the first lens is positive, Wherein, the optical power of the second lens is negative, Wherein, the optical power of the third lens is positive, wherein at least two of the first to fourth lenses are plastic lenses, Wherein, the refractive index of the first lens is 1.7 or greater, The object-side surface and the sensor-side surface of the lens closest to the image sensor among the first to fourth lenses include a critical point between the optical axis and the edge.

2. An optical system comprising: at least two plastic lenses and at least two glass lenses, Among them, the focal power of the lens closest to the object side is positive. Wherein, the composite optical power of the remaining lenses except the lens closest to the object side is positive, wherein the lens having the thinnest thickness on the optical axis among the lenses is one of the glass lenses, and Among the lenses, a lens having the thickest thickness on the optical axis is one of the plastic lenses.

3. The optical system according to claim 2, wherein: The thickest lens on the optical axis is the plastic lens closest to the glass lens.

4. The optical system according to claim 2 or 3, wherein: The object-side surface and the sensor-side surface of the lens farthest from the object include a critical point between the optical axis and the edge.

5. The optical system according to claim 2 or 3, wherein: The refractive index of the lens closest to the object is 1.7 or greater.

6. The optical system according to claim 2 or 3, wherein: The glass lenses are the two lenses closest to the object.

7. The optical system according to claim 2 or 3, wherein: Each of the glass lenses adjacent to the object has a meniscus shape convex toward the object side on the optical axis.

8. The optical system according to claim 2 or 3, wherein: The glass lens is a spherical lens, Wherein, the plastic lens is an aspherical lens, wherein the glass lens closest to the plastic lens has a meniscus shape convex toward the sensor side on the optical axis, The plastic lens closest to the glass lens has a meniscus shape convex toward the sensor side on the optical axis.

9. The optical system according to claim 2 or 3, wherein: The sum of the thickness of the glass lens along the optical axis is ΣGL_CT, Wherein, the optical axis distance from the object side surface of the first lens to the sensor side surface of the fourth lens is TD, Among them, the following formula is satisfied: 0.15≤ΣGL_CT / TD≤0.

25.

10. An optical system comprising: lenses of a first material, the lenses of the first material being arranged continuously along the optical axis; as well as a lens of a second material, the lens of the second material being arranged continuously along the optical axis on the sensor side of the lens of the first material, The lens of the first material includes a lens with an aspherical surface and a lens with a spherical surface. wherein the lens of the second material comprises a lens having an aspherical surface, wherein the first material is different from the second material, and The average value of the center thickness of the lens of the first material is greater than the average value of the center thickness of the lens of the second material.

11. The optical system according to claim 10, wherein: The first material is a glass material, Wherein, the second material is a plastic material.

12. The optical system according to claim 10, wherein: The average refractive index of the lenses of the first material is greater than the average refractive index of the lenses of the second material, The average effective diameter of the lenses made of the first material is greater than the average effective diameter of the lenses made of the second material.

13. An optical system according to any one of claims 10 to 12, in, The number of lenses of the first material is greater than the number of lenses of the second material, The difference between the number of lenses of the first material and the number of lenses of the second material is smaller than the number of lenses of the second material.

14. The optical system according to claim 11, wherein: At least two of the lenses of the first material include cemented lenses bonded to each other, Wherein, the cemented lens includes a lens with positive refractive power and a lens with negative refractive power.

15. An optical system comprising: Image sensor; first to fourth lenses, the first to fourth lenses being aligned along an optical axis from an object toward an image sensor; as well as an optical filter, the optical filter being between the image sensor and the fourth lens, wherein the center thickness of the third lens is greater than the sum of the center thicknesses of each of the first lens and the third lens, wherein each of the effective diameters of the first lens to the third lens is smaller than the diagonal length of the image sensor, Wherein, at least one of the first lens to the fourth lens is a spherical lens, Wherein, at least one of the first lens to the fourth lens is an aspherical lens, Wherein, the distance from the center of the object side surface of the first lens to the surface of the image sensor is TTL, Wherein, the total effective focal length is F, and half of the diagonal length of the image sensor is ImgH, Among them, the following formula 1 is satisfied: 1mm≤F≤10mm, Among them, the following formula 2 is satisfied: 1mm <TTL / ImgH<5mm, Among them, the following formula 3 is satisfied: TTL≤10mm.

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