Optical system and imaging device module

Abstract

An optical system disclosed in an embodiment of the present invention may include first to fifth lenses, in which a combined power of the first and second lenses is negative and a combined power of the third to fifth lenses is positive, among the first to fifth lenses, the second lens has a minimum effective diameter, and the third lens has a minimum effective diameter. An effective diameter of the first lens is larger than an effective diameter of the second lens and smaller than effective diameters of the third to fifth lenses, the third lens among the first to fifth lenses has a maximum power, and the fourth lens among the first to fifth lenses has a second large power.

Description

Technical Field

[0001] The embodiment relates to an optical system and an imaging device module including the optical system. Background Art

[0002] ADAS (Advanced Driver Assistance System) is an advanced driver assistance system for assisting a driver in driving, and ADAS includes sensing a situation ahead, judging a situation based on the sensing result, and controlling the behavior of a vehicle based on the situation judgment. Due to the rapid growth of ADAS globally, a driver monitoring system (DMS) is rapidly becoming an important safety function.

[0003] An imaging device for a DMS linked to an advanced driver assistance system is placed inside a vehicle and can detect the situations of a driver and a passenger. For example, the imaging device can photograph the driver at a position adjacent to the driver and can detect the health condition of the driver, whether he or she is sleepy, whether he or she has consumed alcohol, etc. In addition, the imaging device can photograph 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.

[0004] The most important element for obtaining an image from an imaging device is an imaging lens that forms an image. Recently, there has been an increasing concern about high definition and high resolution, etc., and research on an optical system including multiple lenses is being conducted to achieve this. However, there is a problem that when the imaging device is exposed to harsh environments such as high temperature, low temperature, moisture, or high humidity inside or outside the vehicle, the characteristics of the optical system change. In this case, the imaging device has a problem of being difficult to uniformly derive excellent optical characteristics and aberration characteristics. Therefore, a new optical system and an imaging device that can solve the above problems are needed. Summary of the Invention

[0005] Technical Problem

[0006] The embodiment can provide an optical system and an imaging device module having improved optical characteristics. The embodiment provides an optical system and an imaging device module having excellent optical performance in a low temperature to high temperature environment. The embodiment provides an optical system and an imaging device module capable of preventing or minimizing changes in optical characteristics in various temperature ranges. The embodiment can be provided for an imaging device for the inside of a vehicle or a DMS.

[0007] Technical Solution

[0008] The optical system according to an embodiment of the present invention includes: a first lens to a fifth lens sequentially arranged from the object side, wherein the combined power of the first lens and the second lens is negative, the combined power of the third lens to the fifth lens is positive, among the first lens to the fifth lens, the effective diameter of the second lens is the smallest, the effective diameter of the first lens is greater than that of the second lens and less than that of the third lens to the fifth lens, among the first lens to the fifth lens, the power of the third lens is the largest, and among the first lens to the fifth lens, the power of the fourth lens is the second largest.

[0009] The optical system according to an embodiment of the present invention includes: a first lens to a fifth lens sequentially arranged from the object side, wherein the combined power of the first lens and the second lens is negative, the combined power of the third lens to the fifth lens is positive, among the first lens to the fifth lens, the effective diameter of the second lens is the smallest, among the first lens to the fifth lens, the power of the third lens is the largest, and the optical axis distance from the object side surface of the first lens to the sensor side surface of the second lens can be in the range of 26% to 36% of the optical axis distance from the object side surface of the third lens to the sensor side surface of the fifth lens.

[0010] The optical system according to an embodiment of the present invention includes: a first lens to a fifth lens sequentially arranged from the object side; and an aperture stop disposed on the periphery between the first lens and the second lens, wherein among the first lens to the fifth lens, the effective diameter of the second lens is the smallest, the power of the third lens is positive and the largest among the powers of the first lens to the fifth lens, and the power of the fourth lens is positive and can be greater than the powers of the first lens, the second lens, and the fifth lens.

[0011] According to an embodiment of the present invention, an image sensor is included, and the radii of curvature of the object side surface and the sensor side surface of the fourth lens are the same, and among the first lens to the fifth lens, the central thickness of the fourth lens can be the thickest.

[0012] According to an embodiment of the present invention, the central distance between the third lens and the fourth lens can be greater than the central distance between the first lens and the second lens and the central distance between the second lens and the third lens. According to an embodiment of the present invention, the central distance between the fourth lens and the fifth lens can be the largest among the central distances between the first lens to the fifth lens. According to an embodiment of the present invention, the first lens to the fifth lens can be arranged to be spaced apart from each other along the optical axis. According to an embodiment of the present invention, the power of each of the two lenses with positive power serially arranged on the sensor side of the aperture stop can be at least twice as large as the absolute value of the power of the other lenses.

[0013] According to an embodiment of the present invention, an image sensor may be included, and the optical axis distance from the object side surface of the third lens to the image sensor disposed on the sensor side of the fifth lens may be in the range of 75% to 85% of the optical axis distance from the object side surface of the first lens to the image sensor. According to an embodiment of the present invention, the first lens may have a meniscus shape convex toward the object side from the optical axis, and the second lens may have a meniscus shape convex toward the sensor side from the optical axis.

[0014] According to an embodiment of the present invention, the third lens may have a shape convex in both directions from the optical axis, and the fourth lens may have a shape convex in both directions from the optical axis. The fifth lens may have a meniscus shape convex toward the sensor side from the optical axis. The first lens may have an aspherical object side surface and sensor side surface.

[0015] According to an embodiment of the present invention, the second lens to the fifth lens may have spherical object side surfaces and sensor side surfaces. The effective diameters of the third lens to the fifth lens may be smaller than the diagonal length of the image sensor. The refractive indices of the third lens and the fourth lens may be higher than the average refractive index of the first lens to the fifth lens. The first lens to the fifth lens may be made of glass, and the object side surface and the sensor side surface may be provided without critical points.

[0016] According to an embodiment of the present invention, S7SagD1 is the Sag data at a point spaced a first distance from the center on the object side of the fourth lens, and S8SagD1 is the Sag data at a point spaced the first distance from the center on the sensor side of the fourth lens, and the following formula may be satisfied: |S7SagD1| - |S8SagD1| < 0.2 mm. The first distance is a point that is half of the average effective radius of the object side surface and the sensor side surface of the fourth lens, and the following formulas may be satisfied: S7SagD1 > 0 and S8SagD1 < 0. The maximum distance from a straight line perpendicular to the optical axis on the object side surface of the fifth lens to the object side surface of the fifth lens in the optical axis direction is Max_Sag51, and the maximum distance from a straight line perpendicular to the optical axis on the sensor side surface of the fifth lens to the sensor side surface of the fifth lens in the optical axis direction is Max_Sag52, and the following formula may be satisfied: |Max_Sag52| < |Max_Sag51|. The following formulas may be satisfied: Max_Sag51 < 0 and Max_Sag51 < 0.

[0017] The imaging device module according to an embodiment of the present invention includes: the above optical system, wherein the distance from the object side surface of the first lens to the optical axis of the image sensor is TTL, the total number of lenses is nL, the number of aspherical lenses among the first to fifth lenses is nASL, and half of the diagonal length of the image sensor is ImgH, and the following formula can be satisfied: 3 < TTL / ImgH < 5 and 0 < nASL / nL < 0.5.

[0018] Effects of the Invention

[0019] The optical system and the imaging device module according to the embodiment can have improved optical characteristics. Specifically, in the optical system according to the embodiment, the plurality of lenses can have set thicknesses, powers, and intervals from adjacent lenses. Therefore, the optical system and the imaging device module according to the embodiment can have improved MTF characteristics, aberration control characteristics, resolution characteristics, etc. within a set field of view, and can have good optical performance at the periphery of the field of view.

[0020] The optical system and the imaging device 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 plurality of lenses included in the optical system can have set materials, powers, and refractive indices. Therefore, even when the focal length of each lens changes due to the change in refractive index according to temperature change, the lenses can compensate for each other. That is, the optical system can effectively perform power distribution in the temperature range from low temperature to high temperature, and can prevent or minimize the change in optical characteristics in the temperature range from low temperature to high temperature. Therefore, the optical system and the imaging device module according to the embodiment can maintain improved optical characteristics in various temperature ranges.

[0021] The optical system and the imaging device module according to the embodiment can satisfy a set field of view and achieve excellent optical characteristics by mixing aspherical lenses and spherical lenses. This enables the optical system to provide a thinner vehicle imaging device module. Therefore, the optical system and the imaging device module can be provided for various applications and devices, and can have excellent optical characteristics even in a harsh temperature environment (such as inside a vehicle in high temperature in summer or when exposed to the outside of the vehicle). The embodiment can improve the reliability of the imaging device for vehicle interior or DMS. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a side sectional view of an optical system according to an embodiment and an imaging device module having the optical system.

[0023] Figure 2 is for explaining according to Figure 1A side sectional view of the relationship between the n-th lens and the (n-1)-th lens.

[0024] Figure 3 is a table showing Figure 1 the lens characteristics of the optical system of

[0025] Figure 4 is a table showing Figure 1 the aspherical coefficients of the lenses in the optical system of

[0026] Figure 5 is a table showing Figure 1 the central thickness of each lens and the central distance between adjacent lenses in the optical system of

[0027] Figure 6 is a table showing Figure 1 the sag data from the optical axis to the end of the effective area of the object-side surface and the sensor-side surface of the n-th lens and the (n-1)-th lens in the optical system of

[0028] Figure 7 is a graph showing data on Figure 1 the diffraction MTF (modulation transfer function) of the optical system of

[0029] Figure 8 is a graph showing data on Figure 1 the diffraction MTF of the optical system of

[0030] Figure 9 is a graph showing data on Figure 1 the diffraction MTF of the optical system of

[0031] Figure 10 is a graph showing data on Figure 1 the aberration characteristics of the optical system of

[0032] Figure 11 is a graph showing data on Figure 1 the aberration characteristics of the optical system of

[0033] Figure 12 is a graph showing data on Figure 1 the aberration characteristics of the optical system of

[0034] Figure 13 is an example of a vehicle having an optical system according to an embodiment of the present invention. Detailed Description

[0035] 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 the several embodiments to be described, but can be implemented in various other forms, and within the scope of the technical spirit of the present invention, one or more of the components can be selectively combined and replaced for use. In addition, unless specifically defined and clearly described, the terms (including technical terms and scientific terms) used in the embodiments of the present invention can be interpreted in the meaning generally understood by those of ordinary skill in the art to which the present invention pertains, and common terms such as those defined in a dictionary should be able to have their meanings interpreted in consideration of the context of the related technology.

[0036] The terms used in the embodiments of the present invention are used to illustrate the embodiments and are not intended to limit the present invention. In this specification, unless otherwise specifically stated in a phrase, the singular form may also include the plural form, and in the case of stating at least one (or one or more) of A and (and) B, C, one or more of all combinations that can utilize the combination of A, B, and C may be included. When describing the components of the embodiments of the present invention, terms such as first, second, A, B, (a), and (b) may be used. Such terms are only used to distinguish a component from other components and may not be determined by the nature, sequence, or procedure of the corresponding components according to the terms. And when describing that a component is "connected", "coupled", or "joined" to another component, this description may include not only directly "connecting", "coupling", or "joining" to another component, but also "connecting", "coupling", or "joining" through another component between this component and the other component. In addition, in the case of being described as formed or provided "above (on)" or "below (under)" each component, this description includes not only the case when the two components are in direct contact with each other, but also the case when one or more other components are formed or provided between the two components. In addition, when expressed as "above (on)" or "below (under)", it may refer to the upward direction and the downward direction with respect to an element. Several embodiments described below can be combined with each other, unless 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.

[0037] In the description of the present invention, the "object side surface" may refer to the surface of the lens facing the object side with respect to the optical axis OA, and the "sensor side surface" may refer to the surface of the lens facing the imaging surface (image sensor) with respect to the optical axis. The convex surface of the lens may mean a convex shape on the optical axis or in the paraxial region, while the concave surface of the lens may mean a concave shape on the optical axis or in the paraxial region. The lens curvature radius, the center thickness, and the distance between lenses described in the table of lens data may mean the values on the optical axis and have the unit of mm. The vertical direction may mean the direction perpendicular to the optical axis, and the end of the lens or the lens surface may mean the end or edge of the effective area through which the incident light of the lens passes. Depending on the measurement method, the size of the effective diameter on the lens surface may have a measurement error of up to ±0.4 mm. The paraxial region refers to a very narrow region near the optical axis and is a region where the distance of the light ray from the optical axis OA is almost 0. Hereinafter, the optical axis may include the center of each lens or a very narrow region near the optical axis.

[0038] As Figure 1 and Figure 2 shown, the optical system 1000 according to an embodiment of the present invention may include a plurality of lens groups LG1 and LG2. Specifically, each of the plurality of lens groups LG1 and LG2 includes at least one lens. For example, the optical system 1000 may include a first lens group LG1 and a second lens group LG2 sequentially arranged from the object side toward the image sensor 300 along the optical axis OA. 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 or greater than three times the number of lenses in the first lens group LG1. 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 6, for example, 4 to 6. The first lens group LG1 may include at least one lens. The first lens group LG1 may have two or fewer lenses, for example, one lens. The second lens group LG2 may include three or more lenses or four or more lenses. The second lens group LG2 may include four lenses.

[0039] 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 as a lens made of glass. This glass material undergoes a small amount of expansion and contraction changes due to external temperature variations, and its surface is not easily scratched, thus preventing surface damage. The lens materials of the second lens group LG2 may include at least one glass material lens and at least one plastic material lens. Preferably, the lenses of the second lens group LG2 may include glass lenses. The first lens group LG1 may include at least one aspherical lens. The second lens group LG2 may include at least one spherical lens and at least one aspherical lens. The lenses of the second lens group LG2 may include spherical lenses. Here, a spherical lens is a lens whose object side surface and sensor side surface are spherical on the optical axis, and an aspherical lens is a lens whose object side surface or / and sensor side surface is aspherical. Here, since the first lens is set as the aspherical lens closest to the object, the thickness of the first lens can be set to be thinner than that of the spherical lens, the dispersion can be reduced within a short TTL, and the peripheral image distortion can be reduced. The first lens may be a glass molded lens. A lens made of a glass molding material is a lens injection molded from a glass material to have an aspherical surface. TTL (Total Track Length) 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.

[0040] The optical system 1000 is provided with glass lenses so that thermal compensation can be performed within the lens barrel, and the deterioration of optical characteristics due to temperature changes can be suppressed. Additionally, since the optical system 1000 includes at least one aspherical lens, various aberrations can be suppressed.

[0041] The maximum Abbe number of the lenses of the optical system 1000 is 55 or greater, and the lens with the maximum refractive index is located in the second lens group LG2, and this maximum refractive index can be 1.70 or greater. The lens with the maximum Abbe number can reduce dispersion, and the lens with the maximum refractive index can increase the dispersion of incident light. The refractive index of the i-th lens is Ndi, and the Abbe number of the i-th lens is Adi, and when i is at least one or all of 1, 2, and 5, the value of Ndi * Adi can be the largest. Additionally, the value of Ndi * Adi cannot be greater than 55 when i = 1, 2, 3, 4, and 5, and the value of Ndi * Adi cannot be less than 50. The lens with the smallest effective diameter in the optical system 1000 can satisfy the condition that the value of Ndi * Adi is 80 < (Ndi * Adi) < 120, and * represents multiplication in the specification.

[0042] Within the lens unit 100, the lens with the largest effective diameter can be a spherical lens, and the lens with the smallest effective diameter can be a spherical lens. The effective diameter of each lens can be the diameter of the effective area where effective light is incident on each lens, and is the average of the effective diameter of the object-side surface and the effective diameter of the sensor-side surface. Here, within the lens unit 100, the lens with the largest Sag value in absolute terms is the lens with the smallest effective diameter, and the lens with the second largest Sag value is the nth lens. Here, the Sag value is the distance between the straight line perpendicular to the center of the object-side surface or the sensor-side surface of each lens in the optical axis direction and the object-side surface or the sensor-side surface. Embodiments of the present invention can arrange an aspherical lens on the object side within the optical system 1000 and increase the Sag values of the nth lens and the lens with the smallest effective diameter, so that light can be diffused. Therefore, since there are no critical points on the object-side surface and the sensor-side surface of the nth lens, the total length TTL can be reduced.

[0043] Each lens in the lens can include an effective area and an ineffective area. The effective area can be the area through which the light incident on each lens in the lens passes. That is to say, the effective area can be defined as the area where the incident light is refracted to achieve the effective area or effective diameter of the optical characteristics. The ineffective area can be arranged around the effective area and can be defined as a flange part. The ineffective area can be the area where effective light is not incident on the plurality of lenses. That is to say, the ineffective area can be an area irrelevant to the optical characteristics. In addition, the end of the ineffective area can be the area fixed to the lens barrel (not shown) that houses the lens.

[0044] In the optical system 1000, the TTL (Total Top Length) can be greater than 3 times ImgH, for example, greater than 3 times and less than 5 times. Preferably, the following condition can be satisfied: 3 < TTL / ImgH < 5. 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, so that the optical system can be provided as a standard optical system in a vehicle camera 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 camera device module according to the embodiment can be applied to the camera device module for DMS provided inside the vehicle. The optical system 1000 can have a value of TTL / (2*ImgH) greater than 1.5, and can satisfy, for example, the following condition: 1.5 < TTL / (2*ImgH) < 2.5. The optical system 1000 can provide an optical system for driver monitoring by setting the value of TTL / (2*ImgH) to be less than 2.5. The total number of lenses of the first lens group LG1 and the second lens group LG2 is 6 or less. Therefore, the optical system 1000 can provide an image without image magnification or distortion.

[0045] The length of the image sensor 300 is the maximum length of the diagonal in the direction orthogonal to the optical axis OA. The number of lenses in the optical system 1000 having an effective diameter greater than the diagonal length of the image sensor 300 is 1 or less, and the number of lenses having an effective diameter less than the length of the image sensor 300 can be 4 or more. Preferably, the lens having an effective diameter greater than the diagonal length of the image sensor 300 can be the n-th lens or the (n-1)-th lens or does not exist. The diagonal length of the image sensor 300 can be greater than the diameter of the spherical lens. The diagonal length of the image sensor 300 can be greater than the diameter of the aspherical lens. Preferably, 1 / 2 of the diagonal length of the image sensor 300 can be greater than the minimum effective diameter of the lens.

[0046] The aperture stop ST can control the amount of light incident on the optical system 1000. The aperture stop ST can be disposed between any two lenses in the lens unit 100. The lenses adjacent to the object side and the sensor side of the aperture stop ST have an effective diameter smaller than that of the n-th lens, and the effective diameter of the lens adjacent to the object side of the aperture stop ST can be larger than the effective diameter of the lens adjacent to the sensor side of the aperture stop ST. The effective diameter of the lens adjacent to the sensor side of the aperture stop ST can be the minimum effective diameter. In this way, by reducing the effective diameters of the two lenses adjacent to the aperture stop ST, a thin optical system can be provided. The center thicknesses of the two lenses adjacent to the object side and the sensor side of the aperture stop ST can be thinner than the center thicknesses of the (n - 1)-th lens and the (n - 2)-th lens, so that the TTL can be reduced. In addition, the center thickness of the first lens of the optical system can be set to be thinner than the center thickness of the last lens, and the refraction angle can be increased by the maximum Sag value. By controlling the effective diameter and the Sag value of each of the above lenses, the light incident on the image sensor 300 having pixels of at least 2 megabytes can be controlled, the deterioration of the optical characteristics due to the resolution and temperature changes within the optical system can be compensated, the chromatic aberration control characteristics can be improved, and the vignetting characteristics of the optical system 1000 can be improved.

[0047] Among the lens surfaces disposed between the object and the aperture stop ST, the effective diameter of the lens surface tends to decrease as it goes from the object side to the aperture stop ST. Among the lens surfaces disposed between the aperture stop ST and the image sensor 300, the effective diameter of the lens surface tends to increase as it goes from the aperture stop ST to the sensor side. "The effective diameter of the lens tends to increase as it goes from the aperture stop ST to the sensor side" means that the lens surfaces disposed between the aperture stop ST and the image sensor 300 can include lens surfaces whose effective diameters gradually increase or decrease as they go from the aperture stop ST to the sensor side.

[0048] The aperture stop ST can be disposed 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 can be disposed around the sensor side surface of the lens closest to the object. Alternatively, at least one lens selected from the plurality of lenses can 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 can be used as the aperture stop for controlling the amount of light.

[0049] 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 an aspherical lens and a spherical lens, and may be greater than the center distance between spherical lenses. The optical axis distance between the first lens group LG1 and the second lens group LG2 may be greater than 1 times the optical axis distance of the first lens group LG1, for example, may be in the range of 2 to 3 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 may be less than 0.3 times the optical axis distance of the second lens group LG2, for example, may be 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 of the first lens 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 of the second lens group LG2 and the sensor-side surface of the lens closest to the image sensor 300. Here, the first lens group LG1 may include a lens closer to the object side than the aperture stop ST, and the second lens group LG2 may include a lens closer to the sensor side than the aperture stop ST. The first lens group LG1 and the second lens group LG2 may be divided into an object-side lens group and a sensor-side lens group based on the aperture stop ST. The sensor-side surface of the first lens group LG1 may have a concave shape on the optical axis, and the object-side surface of the second lens group LG2 may have a convex shape on the optical axis, and they may face each other.

[0050] The first lens group LG1 may have a negative (+) focal power, and the second lens group LG2 may have a positive (+) focal power. The lens closest to the object side in the first lens group LG1 may have a positive (+) focal power, and the lens closest to the sensor side in the second lens group LG2 may have a negative (-) focal power. When the absolute value of the focal length of the first lens group LG1 is F_LG1 and the absolute value of the focal length of the second lens group LG2 is F_LG2, the following condition may be satisfied: F_LG2 < F_LG1. Here, when the combined focal length of the first lens 101 and the second lens 102 in the optical system 1000 is F12 and the combined focal length of the third lens 103 to the fourth lens 104 is F34, the following conditions may be satisfied: F12 < F34, and the following condition may be satisfied: F13, F47 > 0. Additionally, the following conditions may be satisfied: F_LG1 < F12 < F_LG2 and F_LG1 < F34 < F_LG2. Here, F_LG1 is the focal length of the first lens 101 and may be defined as F1, and F_LG2 is the combined focal length of the second lens 102 to the fourth lens 104 and may be defined as F24. Additionally, the number of lenses having a negative (-) focal power on the optical system 1000 may be greater than the number of lenses having a positive (+) focal power. The number of lenses having a negative (-) focal power may be greater than 50% of the total number of lenses, and may be in the range of, for example, 51% to 70%.

[0051] The lens unit 100 may be a mixture of spherical lenses and aspherical lenses. The average effective diameter of the aspherical lenses may be smaller than the average effective diameter of the spherical lenses. The average effective diameter of the aspherical lens surfaces may be smaller than the average effective diameter of the spherical lens surfaces. Additionally, the difference between the average effective diameter of the aspherical lenses and the average effective diameter of the spherical lenses may be 0.3 mm or greater, for example, in the range of 0.3 mm to 1.6 mm. Thus, when at least one aspherical lens is arranged in the imaging device module, the weight of the imaging device module may be reduced and the distortion in the peripheral area may be reduced. Additionally, the difference in the effective diameter between the aspherical lens and the spherical lens may be reduced, thereby preventing deterioration of the components.

[0052] The first lens group LG1 refracts the light incident from the object side in the optical axis direction, and the second lens group LG2 refracts the light exiting from the first lens group LG1 to the peripheral area of the image sensor 300. The optical axis distance between the first lens group LG1 and the second lens group LG2 may be 0.8 mm or greater, for example, 2 mm or less.

[0053] In the lens unit 100, the average Abbe number of the spherical material lens may be less than that of the aspherical lens. Since the lens closest to the object is arranged to have a high Abbe number and a low refractive index, dispersion of incident light can be suppressed in an optical system with a small TTL, and the field of view can be widened compared to the focal length. The sum of the refractive indices of the lenses of the lens unit 100 according to the embodiment may be 10 or less, for example, in the range of 6 to 10, and the average value of the refractive indices may be in the range of 1.58 to 1.68. The sum of the Abbe numbers of each lens in the lens may be 220 or more, for example, in the range of 220 to 320, and the average value of the Abbe numbers may be 49 or more, for example, in the range of 49 to 59. 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 in the range of 4 mm to 6 mm. The average value of the center thickness 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 3.6 mm or more, for example, in the range of 3.6 mm to 4.6 mm or in the range of 4.1 mm to 5.1 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 unit 100 may be set to 5 mm or less, for example, in the range of 2 mm to 5 mm or in the range of 3 mm to 5 mm. The difference between the maximum effective diameter and the minimum effective diameter may have a difference of 4 mm or less. Therefore, an optical system in which the difference in the effective diameter of each lens is not large can be provided, and the assembly performance of the lenses assembled in the lens barrel can be improved.

[0054] In the lens unit 100, 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 focal power is Mc, the following conditions can be satisfied: Mb ≤ Ma < Mc, and preferably, the following conditions can be satisfied: Mb < Ma. In the lens unit 100, 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 focal power is Mc, the following conditions can be satisfied: Mb1 ≤ Ma1 < Mc, and preferably, the following conditions can be satisfied: Mb1 < Ma1. The lens surface is the object-side surface and the sensor-side surface of each lens. In the above lens unit 100, the number of spherical lenses is Ga, the number of lenses having an effective diameter smaller than the diagonal length of the image sensor 300 is Gb, and the number of lenses having a positive focal power is Gc. At this time, the following conditions can be satisfied: Gc < Ga ≤ Gc, and preferably, the following conditions can be satisfied: Ga < Gc.

[0055] The F-number of the optical system or the imaging device module according to an embodiment of the present invention 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 2.3. In the optical system according to an embodiment of the present invention, the maximum field of view (diagonal FOV) may be less than 85 degrees, for example, greater than 45 degrees and less than 85 degrees or in the range of 50 degrees to 80 degrees. The horizontal field of view FOV_H of the vehicle optical system in the Y-axis direction may be greater than 40 degrees and less than 60 degrees, for example, in the range of 45 degrees to 59 degrees. The horizontal field of view FOV_H is the field of view based on the horizontal length of the sensor. Therefore, the change in the focal image position due to temperature change can be suppressed, and a vehicle imaging device with various aberrations well corrected can be provided. When the diagonal field of view of the optical system 1000 is in the range of 50 degrees to 80 degrees, if at least one aspherical lens and at least three spherical lenses are provided in the optical system, the average center thickness of the spherical lenses can be set to be thicker than the average center thickness of the aspherical lens. Therefore, the aspherical lens and the spherical lens made of glass can suppress the change in optical performance due to the temperature change from low temperature to high temperature.

[0056] The optical system 1000 or the imaging device 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 the light passing through the lens unit 100 in sequence. The image sensor 300 may include a device that can detect 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 is 95% or more of the maximum effective diameter of the lens, for example, in the range of 95% to 130%, and for example, in the range of 104% to 124%.

[0057] The optical system 1000 or the imaging device module may include a filter 500. The filter 500 may be disposed between the second lens group LG2 and the image sensor 300. The filter 500 may be disposed between the lens closest to the sensor side among the lenses of the lens unit 100 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 filter 500 and the image sensor 300, protects the upper part of the image sensor 300, and prevents deterioration of the reliability of the image sensor 300. The cover glass 400 may be removed. The filter 500 may include an infrared filter or an infrared cut-off filter (IR cut-off). The filter 500 may allow light of a set wavelength band to pass through and filter light of different wavelength bands. When the filter 500 includes an infrared filter, it may block radiant heat emitted from external light from being transmitted to the image sensor 300. Additionally, the filter 500 may transmit visible light and reflect infrared light. The filter 500 may allow wavelengths of 920 nm or greater to pass through, and for example, may allow a wavelength band of 920 nm to 960 nm to pass through.

[0058] Since the embodiment is an optical system applied to a vehicle imaging device, the first lens 101 may be made of a glass material, even though the first lens 101 is designed to use an aspherical lens and a spherical lens together. This is because the glass material has the advantages of scratch resistance and insensitivity to external temperature compared to plastic materials. Since the first lens 101 has a convex shape facing the driver inside the vehicle, the first lens 101 can more effectively prevent the accumulation or scratching of foreign objects and can improve the incident efficiency. Therefore, the reliability of the driver monitoring imaging device module can be improved. The optical system 1000 according to the embodiment may further include a reflection member (not shown) for changing the path of light. The reflection member may be implemented as a prism that reflects the incident light of the first lens group LG1 towards the lens.

[0059] Hereinafter, the optical system according to the embodiment will be described in detail.

[0060] Hereinafter, the optical system according to an embodiment of the present invention will be described. Referring to Figures 1 to 3, the optical system 1000 according to the embodiment includes a lens unit 100, and the lens unit 100 may include a first lens 101 to a fifth lens 105. The first lens to the fifth lens 101, 102, 103, 104, and 105 may be arranged in sequence along the optical axis OA. Light corresponding to information about an object may pass through the first lens 101 to the fifth lens 105 and the filter 500 and be incident on the image sensor 300. The first lens 101 is a lens of the first lens group LG1 and is the lens closest to the object side. The fifth lens 105 is the lens closest to the image sensor 300 in the second lens group LG2 or the lens unit 100. The second lens to the fifth lens 102, 103, 104, and 105 may be the second lens group LG2.

[0061] As the combined focal lengths of the lenses, F12, F24, and F34 may satisfy the following conditions. F12 is the combined focal length of the first lens and the second lens, F34 is the combined focal length of the third lens and the fourth lens, and F25 is the combined focal length of the second lens to the fifth lens. Diopter is the reciprocal of the focal length.

[0062] Condition 1: F25 > 0 Condition 2: F35 > 0

[0063] Condition 3: F12 < 0 Condition 4: F34 > 0

[0064] Condition 5: F35 < |F12| Condition 6: F25 < |F12|

[0065] The first lens 101 may have a positive (+) diopter or a negative (-) diopter on the optical axis OA. The first lens 101 may have a negative (-) diopter. 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 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.

[0066] The object-side first surface S1 of the first lens 101 based on the optical axis may have a convex shape, and the sensor-side second surface S2 may have a concave shape. The first lens 101 may have a meniscus shape convex from the optical axis toward the object side. In contrast, the first surface S1 may have a concave shape on the optical axis OA, and the second surface S2 may have a convex shape. The first surface S1 and the second surface S2 of the first lens 101 may be aspherical on the optical axis, and the aspheric coefficient may be set to Figure 4L1S1 and L1S2. Since the first lens 101 is arranged as an aspherical lens made of glass, when the temperature changes to a low temperature or a high temperature, the movement of the optical axis can be suppressed, thereby preventing deterioration of the optical performance. In addition, even if the thickness of the lens is designed to be thin due to the aspherical material made of glass, the distortion of the peripheral portion of the lens can be improved. In contrast, when the first lens 101 is a spherical lens, the focal power can be negative.

[0067] The first lens 101 has a convex first surface S1 and a concave second surface S2 on the optical axis, such that incident light can be refracted in a direction close to the optical axis. Therefore, the marginal spacing between the first lens 101 and the second lens 102 and the effective diameter of the second lens 102 can be reduced. Since the first lens 101 is arranged such that the marginal thickness is thicker than the central thickness, the first lens 101 can be insensitive to assembly tolerances. Being insensitive to assembly tolerances means that even if the components are assembled with a slight difference compared to the design, the optical performance is not significantly affected.

[0068] The aperture stop ST can be provided on the periphery between the first lens 101 and the second lens 102. The aperture stop ST can be provided on the periphery of the object-side surface of the second lens 102. The aperture stop ST can be arranged to be closer to the object-side surface of the second lens 102 than to the sensor-side surface of the first lens 101. Alternatively, the aperture stop ST can be provided around the sensor-side surface of the second lens 102 or around the object-side surface of the first lens 101. Since the aperture stop ST is provided around the periphery between the first lens 101 and the second lens 102, the difference in the effective diameter between the first lens 101 and the second lens 102 can be reduced. The first lens 101 and the second lens 102 on both sides of the aperture stop ST can have the same sign of focal power. The difference in the focal power between the first lens 101 and the second lens 102 on both sides of the aperture stop ST can be 10% or less of the average focal power of the two lenses.

[0069] The second lens 102 may be disposed between the first lens 101 and the third lens 103. The second lens 102 may have a positive (+) focal power or a negative (−) focal power on the optical axis OA. The second lens 102 may have a negative (−) focal power. The second lens 102 may include a plastic or glass material. For example, the second lens 102 may be set as a glass material. The object-side third surface S3 of the second lens 102 on the optical axis OA may be concave, and the sensor-side fourth surface S4 may have a convex shape. The second lens 102 may have a convex meniscus shape toward the sensor side on the optical axis. Alternatively, the third surface S3 may be convex, and the fourth surface S4 may be concave. In contrast, the second lens 102 may have a concave shape on both sides. The second lens 102 may be set as a spherical lens made of glass. The third surface S3 and the fourth surface S4 may be spherical. 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 fifth lens 105. The center distance between the first lens 101 and the second lens 102 may be greater than the sum of the center thicknesses of the first lens 101 and the second lens 102. The edge distance between the first lens 101 and the second lens 102 may be less than the sum of the center thicknesses of the first lens 101 and the second lens 102. Here, the edge distance is the optical axis distance between the end of the effective area of the sensor-side surface of the object-side lens and the end of the effective area of the object-side surface of the sensor-side lens among two adjacent lenses.

[0070] The effective diameters of the first lens 101 and the second lens 102 disposed on the object side and the sensor side of the aperture stop ST may be smaller than the effective diameters of the third lens to the fifth lens 103, 104, and 105. Additionally, the effective diameters of the first lens 101 and the second lens 102 adjacent to the aperture stop S5 may be smaller than the effective diameter of the first lens 101, and the effective diameter of the second lens 102 closer to the aperture stop ST may be smaller than the effective diameter of the first lens 101, and the effective diameter of the first lens 101 may be smaller than the effective diameter of the third lens 103, which is closer to the aperture stop ST among the third lens to the fifth lens 103, 104, and 105. When the aperture stop ST is placed between the first lens 101 and the second lens 102 to reduce the TTL, the effective diameters of the two lenses adjacent to the aperture stop ST may be designed to be smaller than those of the other lenses. Additionally, since the effective diameters of the first lens 101 and the second lens 102 are small, the center thickness is thin, and the distance between the first lens 101 and the second lens 102 is reduced, the TTL can be reduced, but distortion and aberration of the light traveling through the first lens 101 and the second lens 102 may occur. Therefore, in order to suppress the distortion and aberration of the light, the first lens 101 may be set as an aspherical lens. Additionally, the distortion and aberration that occur to reduce the TTL are corrected by adjusting the refractive index, thickness, Abbe number, radius of curvature, and the distance between adjacent lenses of the third lens to the fifth lens 103, 104, and 105. The powers, distances, and thicknesses of the third lens 103 and the fourth lens 104 for reducing distortion / aberration will be described later. If the aperture stop ST is set on the object side of the first lens 101, the TTL can be further reduced, but in this structure, the aberration and distortion of the optical system become more serious, and it is difficult to correct the aberration and distortion using other lenses, or the TTL may increase and the size of the imaging device module may also increase.

[0071] The third lens 103 may have a positive (+) power or a negative (-) power on the optical axis OA. The third lens 103 may have a positive (+) power. The third lens 103 may include a plastic or glass material. For example, the third lens 103 may be made of plastic. The power of the third lens 103 may be set to at least twice the absolute value of the powers of the first lens 101, the second lens 102, and the fifth lens 105 to correct distortion and aberration. The fifth surface S5 on the object side of the third lens 103 on the optical axis may have a convex shape, and the sixth surface S6 on the sensor side may have a convex shape. The third lens 103 may have a convex shape on both sides of the optical axis. In contrast, the third lens 103 may have a convex meniscus shape facing the sensor on the optical axis or a concave shape on both sides.

[0072] The third lens 103 may be a spherical lens made of glass. The center thickness of the third lens 103 may be at least twice or at least three times the center thicknesses of the first lens 101 and the second lens 102. Since the third lens 103 has a convex shape on both sides, the center thickness may be greater than the edge thickness. The effective diameter of the third lens 103 may be greater than the effective diameters of the first lens 101 and the second lens 102. Since the object-side surface of the third lens 103 has a convex shape on the optical axis and the sensor-side surface of the second lens 102 has a convex shape, the center distance between the second lens 102 and the third lens 103 may be the smallest among the center distances of the lenses.

[0073] The fourth lens 104 may have a positive (+) focal power or a negative (-) focal power on the optical axis OA. The fourth lens 104 may have a positive (+) focal power. The fourth lens 104 may include a plastic or glass material. For example, the fourth lens 104 may include a glass material. The focal power of the fourth lens 104 may be set to be more than twice the absolute values of the focal powers of the first lens 101, the second lens 102, and the fifth lens 105, so as to correct distortion and aberration. The object-side seventh surface S7 of the fourth lens 104 on the optical axis may be convex, and the sensor-side eighth surface S8 may have a convex shape. The fourth lens 104 may have a shape that is convex on both sides on the optical axis. Alternatively, the fourth lens 104 may have a meniscus shape that is convex toward the sensor side or a shape that is concave on both sides. The fourth lens 104 may be set as a spherical lens made of glass. At least one of the seventh surface S7 and the eighth surface S8 of the fourth lens 104 may be set to have no critical points. The fourth lens 104 may be the n-1 lens and may have the largest effective diameter among the lenses. The center thickness of the fourth lens 104 may be at least twice or at least three times the center thicknesses of the first lens 101 and the second lens 102. The center thicknesses of the third lens 103 and the fourth lens 104 may be at least twice or at least three times the smallest center thickness of the lenses.

[0074] Since the sensor-side surface of the third lens 103 has a convex shape on the optical axis and the object-side surface of the fourth lens 104 has a convex shape on the optical axis, the center distance between the third lens 103 and the fourth lens 104 can be greater than the sum of the center thicknesses of the first lens 101 and the second lens 102. Additionally, the edge distance between the third lens 103 and the fourth lens 104 can be greater than the center distance between the third lens 103 and the fourth lens 104. This is because the sensor-side surface of the third lens 103 has a radius of curvature smaller than that of the object-side surface and is set to a convex curved shape such that the third lens 103 can refract light to the periphery of the fourth lens 104 having the maximum effective diameter. Since the fourth lens 104 has a convex shape on both sides, the center thickness can be greater than the edge thickness. The difference between the absolute value of the radius of curvature of the object-side surface and the absolute value of the radius of curvature of the sensor-side surface of the fourth lens 104 can be smaller than the difference between the absolute value of the radius of curvature of the object-side surface and the absolute value of the radius of curvature of the sensor-side surface of the third lens 103. The difference between the absolute value of the radius of curvature of the object-side surface and the absolute value of the radius of curvature of the sensor-side surface of the fourth lens 104 can be the smallest among the lenses. The power of each of the third lens 103 and the fourth lens 104 arranged in sequence along the optical axis is arranged to be at least twice the absolute value of the power of the first lens 101, the second lens 102, and the fifth lens 105, thereby correcting the distortion and aberration that occur in the first lens 101 and the second lens 102. Among the third lens 103 and the fourth lens 104, the power of the third lens 103 adjacent to the first lens 101 and the second lens 102 can be the largest.

[0075] To correct the distortion and aberration caused by the first lens 101 and the second lens 102, the center distance between the second lens 102 and the third lens 103 can be reduced, the center thicknesses of the third lens 103 and the fourth lens 104 can be set to be thicker than those of the other lenses, and the center distance between the third lens 103 and the fourth lens 104 can be set to be greater than the center distance between the first lens 101 and the second lens 102. The third lens 103 and the fourth lens 104 can correct the distortion and aberration of the light passing through the first lens 101 and the second lens 102 in the direction where the distortion and aberration are removed, and then refract the light to the entire area of the fifth lens 105.

[0076] The fifth lens 105 may have a positive (+) or negative (-) focal power on the optical axis OA. The fifth lens 104 may have a negative (-) focal power. The fifth lens 105 may include a plastic or glass material. For example, the fifth lens 105 may include a glass material. The object-side ninth surface S9 of the fifth lens 105 on the optical axis may be concave, and the sensor-side tenth surface S10 may have a convex shape. The fifth lens 105 may have a convex shape on the optical axis toward the sensor side. Alternatively, the fifth lens 105 may have a meniscus shape convex toward the object side on the optical axis or may have a concave shape on both sides. The fifth lens 105 may be provided as a spherical lens made of glass. At least one of the ninth surface S9 and the tenth surface S10 of the fifth lens 105 may be provided without a critical point. The fifth lens 105 may be the nth lens and may have the second largest effective diameter among the lenses. The center thickness of the fifth lens 105 may be 1 / 2 times or 1 / 3 times or less than the center thicknesses of the third lens 103 and the fourth lens 104. The center thickness of the fifth lens 105 may differ from the center thicknesses of the first lens 101 and the second lens 102 by 10% or less. The fifth lens 105 is provided such that the edge thickness is thicker than the center thickness, so that light can be refracted through the periphery to the entire area of the image sensor 300.

[0077] Since the sensor-side surface of the fourth lens 104 has a convex shape on the optical axis and the object-side surface of the fifth lens 105 has a concave shape on the optical axis, the center distance between the fourth lens 104 and the fifth lens 105 may be the largest among the center distances between the lenses. Additionally, the distance between the fourth lens 104 and the fifth lens 105 may be such that the edge distance is less than the center distance. The fifth lens 105 may be the spherical lens closest to the image sensor 300. By arranging the spherical lens as the lens closest to the image sensor 300, the assemblability can be improved compared to an aspherical lens. Since the object-side surface of the fifth lens 105 has a curved shape with the edge adjacent to the end of the effective area of the fourth lens 104 and the center being concave, the light refracted by the fourth lens 104 can be incident. Thus, the center distance between the fifth lens 105 and the fourth lens 104 can be ensured to be the largest, and an increase in the effective diameter of the fifth lens 105 can be suppressed. Furthermore, since the sensor-side surface of the fifth lens 105 is provided as a convex curved shape, light can be refracted to the entire area of the image sensor 300 even without an aspherical surface. As another example, the fifth lens 105 may be a glass lens having an aspherical surface.

[0078] Refer to Figure 2, at least one of the ninth surface S9 and the tenth surface S10 of the fifth lens 105 may be set to have no critical points. A critical point is a point where the trend of the Sag value changes. That is, a critical point is a point where the Sag value increases and then decreases, or a point where the Sag value decreases and then increases. The Sag value is the 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 on the sensor side with respect to the center of each lens surface, and has a negative value at a position on the object side with respect to the center of each lens surface. When expressed as the absolute value of the Sag value, the maximum value of Sag51 may be greater than the maximum values of Sag41, Sag42, and Sag52. Sag51 is the optical axis distance between the object-side surface of the fifth lens 105 and a straight line perpendicular to the center of the object-side surface of the fifth lens 105, Sag41 is the optical axis distance between the object-side surface of the fourth lens 104 and a straight line perpendicular to the center of the object-side surface, Sag42 is the optical axis distance between the sensor-side surface of the fourth lens 104 and a straight line perpendicular to the center of the sensor-side surface, and Sag52 is the optical axis distance between the sensor-side surface of the fifth lens 105 and a straight line perpendicular to the center of the sensor-side surface of the fifth lens 105.

[0079] In addition, the Sag values of the seventh surface S7 on the object side and the eighth surface S8 on the sensor side of the fourth lens 104 may have different signs and may have a difference of less than 0.2 mm. For example, the Sag values of the seventh surface S7 and the eighth surface S8 may be less than 0.2 mm at 0.1 mm, 0.2 mm, 1 mm, 2 mm, 3 mm, the end, or the edge from the optical axis. In addition, the fourth lens 104 may have an absolute value of the Sag values of the seventh surface and the eighth surface S8 of less than 0.2 mm at a distance D1 of 1 / 2 of the effective radius from the optical axis. The absolute values of the Sag values of the seventh surface and the eighth surface S8 may gradually increase toward the edge on the optical axis and may have the same value at the same distance from the optical axis.

[0080] The 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. The BFL can be 1.5 mm or greater, and it can ensure the installation space for the filter 500 or the installation space for the filter 500 and the cover glass 400. CT4 is the center thickness or the optical axis thickness of the fourth lens 104, and ET4 is the edge thickness of the fourth lens 104. CT5 is the center thickness or the optical axis thickness of the fifth lens 105, and ET5 is the edge thickness of the fifth lens 105. The edge thickness is the distance between the object-side surface and the sensor-side surface at the end of the effective area of each lens in the optical axis direction. CG4 is the optical axis distance (i.e., the center gap) from the center of the sensor-side surface of the fourth lens 104 to the center of the object-side surface of the fifth lens 105. That is, CG4 is the distance from the center of the eighth surface S8 to the center of the ninth surface S9. EG4 is the optical axis distance (i.e., the edge gap) from the edge of the sensor-side surface of the fourth lens 104 to the edge of the object-side surface of the fifth lens 105.

[0081] In the optical system 1000, at least one lens having an aspherical surface has an effective diameter smaller than the average effective diameter of the spherical lenses and is arranged closest to the object side, so that light can be guided to the entire area of the image sensor through a small number of lenses in the optical system. 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 and the fifth lens 105 can be disposed on the sensor side of the aperture stop ST. Here, the effective diameters of the first lens 101 to the fifth lens 105 are defined as CA1, CA2, CA3, CA4, and CA5, and the effective diameters of the object-side surfaces and the sensor-side surfaces of the first lens 101 to the fifth lens 105 can be defined as CA11, CA12, CA21, CA22, CA31, CA32, CA41, CA42, CA51, and CA52. When the aperture stop ST is disposed on the object-side surface of the second lens 102, the following conditions can be satisfied.

[0082] Condition 1: CA2 < CA1 < CA3 < CA4 < CA5

[0083] Condition 2: (CA4 - CA5) < (CA1 - CA2)

[0084] Condition 3: CA2 < ImgH < CA4 < (2 * ImgH)

[0085] Condition 4: CA21 < CA11 < CA32 < CA42

[0086] Condition 5: CA51 < CA41 < CA52

[0087] Since the second lens 102 disposed on the sensor side of the aperture stop ST has a negative focal power (F2 < 0), the second lens 102 can refract incident light. Additionally, since the third lens 103 has a convex shape on both sides, the third lens 103 can refract light rays toward the edge of the fourth lens. Therefore, it is possible to prevent a decrease in the weighing yield of the optical system by the second lens 102 and the third lens 103, and it is possible to improve production efficiency. Here, the combined focal power of the second lens 102 to the fifth lens 105 disposed on the sensor side of the aperture stop ST may have a positive value, and the TTL within the field of view can be reduced.

[0088] The distance between the first lens 101 and the second lens 102 can gradually decrease from the center to the edge.

[0089] The distance between the second lens 102 and the third lens 103 can gradually increase from the center to the edge. This distance can gradually increase from the optical axis to the edge due to the convex shape of the sensor-side surface of the second lens 102 and the convex shape of the object-side surface of the third lens 103.

[0090] Figure 3 is Figure 1 an example of the lens data of the optical system of the embodiment. As Figure 3As shown, it is possible to set the curvature radii of the first to fifth lenses 101, 102, 103, 104, and 105 on the optical axis OA, the center thickness CT of the lenses, the center distance CG between adjacent lenses, the refractive index at the d-line, the Abbe number, and the size of the effective radius (e.g., the semi-aperture). When the curvature radius of each lens on the optical axis is expressed as an absolute value, the curvature radius of each of the first to fifth lenses 101 to 105 on the optical axis OA can be 30 mm or less, for example, in the range of 1 mm to 30 mm or in the range of 1 mm to 20 mm. Additionally, the difference in the curvature radii of two adjacent lens surfaces can be less than 30 mm, for example, in the range of 0.1 mm to 25 mm or in the range of 0.1 mm to 15 mm. Therefore, light can be guided without increasing the difference in the curvature radii of the optical system 1000 having six or fewer lenses. In absolute value, the difference in the curvature radii between the first surface S1 and the second surface S2 is 5 mm or less, the difference in the curvature radii between the second surface S2 and the third surface S4 is 3 mm or less, the difference in the curvature radii between the third surface S3 and the fourth surface S4 is 5 mm or less, the difference in the curvature radii between the fourth surface S4 and the fifth surface S5 is 15 mm or less, the difference in the curvature radii between the fifth surface S5 and the sixth surface S6 is 15 mm or less, the difference in the curvature radii between the sixth surface S6 and the seventh surface S7 is 15 mm or less, the difference in the curvature radii between the seventh surface S7 and the eighth surface S8 is 1 mm or less, the difference in the curvature radii between the eighth surface S8 and the ninth surface S9 is 15 mm or less, and the difference in the curvature radii between the ninth surface S9 and the tenth surface S10 can be 15 mm or less. Here, the curvature radius of the glass lens can be 5% or more of the effective radius and can be set, for example, in the range of 5% to 95%.

[0091] When the curvature radius of each lens on the optical axis is expressed as an absolute value, the curvature radius of the fifth surface S5 of the third lens 103 can be the largest among the curvature radii of the lenses. Either the curvature radius of the second surface S2 of the first lens 101 or the curvature radius of the third surface S3 of the second lens 102 can be the smallest among the lenses. The maximum curvature radius can be less than 30 mm, for example, 25 mm or less, and can be 15 times or less the minimum curvature radius, for example, 5 times to 15 times. The curvature radius of the first lens 101, which is an aspherical lens, can be less than the curvature radius of at least one or all of the second to fifth lenses 102 to 105 made of spherical material. Here, the curvature radius is the average value of the absolute values of the curvature radii of the object-side surface and the sensor-side surface of each lens.

[0092] When expressed in absolute value, the radius of curvature of the first lens 101 disposed on the object side of the aperture stop ST on the optical axis can be smaller than the radius of curvature of the second lens 102 disposed on the sensor side of the aperture stop ST. When expressed in absolute value, the radius of curvature of the fourth lens 104 on the optical axis can be greater than the radius of curvature of the third lens 103. When expressed in absolute value, the difference in the radius of curvature between the object-side surface and the sensor-side surface of the third lens 103 is greater than the difference in the radius of curvature between the object-side surface and the sensor-side surface of the fourth lens 104, and can be greater than the difference in the radius of curvature between the object-side surface and the sensor-side surface of the fifth lens 105. The difference in the radius of curvature between the object-side surface and the sensor-side surface of the third lens 103 can be the largest among the differences in the radius of curvature between the object-side surface and the sensor-side surface of each lens.

[0093] If the first lens 101 is designed as an aspherical surface made of glass, thermal compensation can be satisfied and optical performance can be improved, but it may not be as easy to assemble as a spherical lens, and the optical characteristics of the lens disposed on the sensor side may be affected by the aspherical first lens 101. If the first lens is a spherical lens, even if the optical characteristics of the first lens are affected, the radius of curvature of the first lens will not change significantly due to the spherical characteristics. In the present invention, the radius of curvature of the first lens 101 having an aspherical surface is designed to be 10 m or less and the effective diameter is designed to be small, so that assembly can be easy, and even if assembled slightly inclined from the optical axis, the influence on the lens on the sensor side can be minimized. Since the third lens 103 to the fifth lens 105 are provided as spherical surfaces, the difference in the radius of curvature between the object-side surface and the sensor-side surface can be small, and assembly can be improved by a large effective diameter, and the influence on the optical characteristics can be reduced.

[0094] 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 ninth surface S9 and the tenth surface S10 of the fifth lens 105 are defined as L5R1 and L5R2, and the radii of curvature of each lens surface of the second lens 102, the third lens 1031, and the fourth lens 104 can be defined as L2R1, L2R2, L3R1, L3R2, L4R1, and L4R2. The ratios of the radii of curvature of the object-side surface and the sensor-side surface of each lens are as follows:

[0095] Condition 1: 1 < L1R1 / L1R2 < 3 Condition 2: 0 < L2R1 / L2R2 < 1

[0096] Condition 3: 1.2 < |L3R1 / L3R2| < 5 (assuming L3R1 > 0, L3R2 < 0)

[0097] Condition 4: 0.5 < |L4R1 / L4R2| < 1.5; Condition 5: 0 < |L5R1 / L5R2| < 1

[0098] Condition 6: 0 mm ≤ |L4R1| - |L4R2| ≤ 1 mm

[0099] Preferably, Condition 5 is satisfied such that: |L4R1| - L4R2 ≤ 0.2 mm. Preferably, the absolute values of L4R1 and L4R2 may be equal to each other or have a difference with a tolerance less than the radius of curvature. The tolerance of the radius of curvature may be ±0.05 mm. If the difference in the radius of curvature between the seventh surface S7 on the object side and the eighth surface S8 on the sensor side of the fourth lens 104 is designed to be within the above range or tolerance, the object-side surface and the sensor-side surface can be assembled without distinction, thereby improving the convenience of assembly. If the difference in the radius of curvature between the seventh surface S7 on the object side and the eighth surface S8 on the sensor side of the fourth lens 104 exceeds 0.2 mm, it may be difficult to distinguish between the two lens surfaces S7 and S8, and there may be a problem that the two lens surfaces S7 and S8 are assembled in reverse.

[0100] In addition, 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, then when i = 1, the value of LiR1 / LiR2 (i = 1 to 5) can be the largest, and when i = 5, it is the smallest. In addition, the difference in the radius of curvature between adjacent aspherical lens surfaces and spherical lens surfaces may satisfy the following conditions.

[0101] Condition 7: 0.5 < |L1R2| / L2R1 < 1.4

[0102] The difference in the radius of curvature between the spherical lens surface and the aspherical lens surface is set to be 1 mm or less, for example, in the range of 0.1 mm to 1 mm, so that the chromatic aberration between the lens surfaces can be corrected.

[0103] When the central thicknesses of the first lens 101 to the fifth lens 105 are defined as CT1 to CT5 and the edge thicknesses of the first lens 101 to the fifth lens 105 are defined as ET1 to ET5, the sum of the central thicknesses of the first lens 101 to the fifth lens 105 can be defined as ∑CT, and the sum of the edge thicknesses of the first lens 101 to the fifth lens 105 can be defined as ∑ET. In terms of the thickness of the lens, the central thickness CT4 of the fourth lens 104 can be greater than the central thicknesses CT1, CT2, and CT5 of the first lens 101, the second lens 102, and the fifth lens 105, respectively, and preferably, can have the largest thickness among the lenses. Since the central thickness CT4 of the fourth lens 104 is the largest and the radius of curvature of the sensor-side surface is the largest among the radii of curvature of the sensor-side surfaces of each lens, the incident light can be refracted to the end of the effective area of the last lens. That is, in order to control the optical path generated due to the TTL of 20 mm or less and the effective diameter and lens shape of the fourth lens 104, the fifth lens 105 can have a convex meniscus shape toward the sensor side.

[0104] The ratio of the central thickness to the edge thickness of each lens can satisfy the following conditions.

[0105] Condition 1: 0 < CT1 / ET1 < 1 Condition 2: 0 < CT2 / ET2 < 1

[0106] Condition 3: 0.5 < CT3 / ET3 < 1.5 Condition 4: 0.1 < CT4 / ET4 < 1.1

[0107] Condition 5: 0 < CT4 / ET4 < 1

[0108] Condition 6: 0.1 < ∑CT / ∑ET < 1.1 or 0.3 < ∑CT / ∑ET < 1

[0109] Condition 7: CT1 / ∑CT < 0.3 Condition 8: 0.15 < CT4 / ∑CT < 0.7

[0110] In the conditions, when CTi / ETi (i = 1 to 5), it can be the largest when i is 3 and the smallest when i is 1. The difference between the central thickness and the edge thickness of each lens can be set to be greater than 0.01 mm and less than 2 mm. In addition, by placing an aspherical lens in the first lens 101 and designing the ratio of the central thickness to the edge thickness to be the largest, assembly deterioration caused by the aspherical lens can be prevented.

[0111] In order to set the edge thickness of the third lens 103 and the fourth lens 104 to 0.6 mm or greater, the center thickness of the third lens 103 and the fourth lens 104 can be set thick, and the radius of curvature of the object-side surface and the sensor-side surface can be set large. By setting the difference between the center thickness and the edge thickness of the fourth lens 104 within the range of Condition 4, the difference in the radius of curvature between the object-side surface and the sensor-side surface can be designed not to be large, and the assemblability of the fourth lens 104 can be improved. 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, within the range of 0.5 mm to 2 mm or 1 mm to 1.5 mm. That is, even if the center thickness of the last spherical lens is set thin, the optical performance will not deteriorate, and the thickness of the imaging device module can be set thin. In addition, since the difference between the center thickness and the edge thickness of each lens is not large, even if at least one lens is tilted, the influence on the optical characteristics can be reduced. In addition, the glass lens can reduce the influence of the thermal characteristics between the center and the edge of each lens.

[0112] The maximum center thickness can be greater than the sum of the center thicknesses of two different lenses. For example, the following conditions can be satisfied: (CT1 + CT2) < CT4, (CT1 + CT5) < CT4, and (CT2 + CT5) < CT4. The center thickness of the third lens 103 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 + CT5) < CT3, and (CT2 + CT5) < CT3.

[0113] The center distances between the first lens 101 to the fifth lens 105 are defined as CG1 to CG4, and the sum of the center distances between the first lens 101 to the fifth lens 105 can be defined as ∑CG. The center distances between two adjacent lenses among the second lens 102 to the fifth lens 105 are CG2, CG3, and CG4, which are the center distances between the spherical lenses. The center distance between the first lens 101 and the second lens 102 is CG1, which is the center distance between the spherical lens and the aspherical lens. The center distance CG4 between the fourth lens 104 and the fifth lens 105 is the largest within the lens unit 100 and can be greater than the center distance between the aspherical lens and the spherical lens. The center thickness of each lens and the center distance between adjacent lenses can satisfy the following conditions.

[0114] Condition 1: 0 < CT1 / CG1 < 1 Condition 2: 1.5 < CT2 / CG2 < 4

[0115] Condition 3: 1 < CT3 / CG3 < 2 Condition 4: 0.5 < CT4 / CG4 < 1.5

[0116] Condition 5: 0 < CT5 / CG4 < 1; Condition 6: (CT1 / CG1) < (CT4 / CG4) < (CT3 / CG3)

[0117] Condition 6: 0 < CG3 / ∑CG < 0.5; Condition 7: 0.5 < CT_Max / CG_Max < 1.5

[0118] By setting the maximum center thickness between the lenses to at least twice the maximum center distance, for example, within the range of 2.1 times to 4.5 times, a camera device module applying an aspherical lens in an optical system can be provided without increasing the center thickness of each lens compared to the center distance. In Condition 3, since the spherical third lens 103 and fourth lens 104 are both set to a convex shape on both sides, the center distance between the third lens 104 and the fourth lens 105 can be reduced. Here, if the i-th center distance among the center distances between two adjacent lenses is defined as CGi, and the center thickness of the i-th lens on the object side relative to CGi is defined as CTi, the following conditions can be satisfied. The ratio of CTi / Cgi can be the largest when i is 2 and the smallest when i is 1. The following conditions can be achieved by the different meniscus shapes of the spherical lens and the aspherical lens: when i is 2, the value of CTi / CGi is the largest.

[0119] If the optical axis distance from the center of the object-side surface of the first lens 101 to the surface of the image sensor 300 is TTL, the following conditions can be satisfied.

[0120] Condition 1: 0 < CT1 / TTL < 0.2

[0121] Preferably, Condition 1 can be satisfied as: 0.05 ≤ CT1 / TTL ≤ 0.15. Since the first lens 101 is made of the glass material of the aspherical lens, an optical system satisfying thermal compensation according to temperature change can be designed by the thickness of the first lens 101 that satisfies Condition 1. That is, Condition 1 can be a characteristic presented by designing the first lens 101 as an aspherical glass.

[0122] Condition 2: 0 < CT2 / TTL ≤ 0.15; Condition 3: 0.15 < CT3 / TTL < 0.5

[0123] Condition 4: 0.1 < CT4 / TTL < 0.3; Condition 5: 0 < CT5 / TTL ≤ 0.15

[0124] The ratio of CT1 / TTL in the above Condition 3 and Condition 4 can be greater than the values in Condition 1, Condition 2, and Condition 5.

[0125] In terms of refractive index, the refractive index of the third lens 103 is the largest among the refractive indices of the lenses, and preferably, the refractive indices of the third lens 103 and the fourth lens 104 can be 1.7 or greater. The difference in refractive index between the third lens 103 and the fourth lens 104 is 0.20 or less. When the refractive indices of the third lens 103 and the fourth lens 104 are arranged to be higher than the refractive indices of the first lens 101, the second lens 102, and the fifth lens 105, the dioptric powers of the third lens 103 and the fourth lens 104 can be increased, and an increase in the radii of curvature of the object-side surface and the sensor-side surface can be suppressed. Therefore, the sensitivity of the light traveling through the third lens 103 and the fourth lens 104 can be reduced. The refractive indices of the third lens 103 and the fourth lens 104 can be higher than the average refractive index of the first lens 101 to the fifth lens 105. The refractive indices of the first lens 101, the second lens 102, and the fifth lens 105 can be less than 1.6. By setting the refractive indices of the first lens 101 to the fifth lens 105, chromatic dispersion can be controlled. Since the center thickness and the edge thickness of the third lens 103 and the fourth lens 104 are set to be thicker than the center thickness and the edge thickness of the other lenses, an increase in the radii of curvature of the object-side surface and the sensor-side surface of the third lens 103 and the fourth lens 104 can be suppressed. Chromatic dispersion may increase due to the high refractive indices of the third lens 103 and the fourth lens 104 and the edge thickness being thinner than the center thickness. The first lens 101 has a shape in which the object-side surface protrudes toward the driver, so that the amount of incident light can be increased.

[0126] In terms of Abbe number, the Abbe number of at least one or all of the first lens 101, the second lens 102, and the fifth lens 105 is the largest among the lenses and can be 55 or greater. The Abbe number of the third lens 103 is the smallest among the lenses. The difference between the largest Abbe number and the smallest Abbe number can be 20 or greater. By reducing the difference in Abbe number or refractive index between the object-side lens and the sensor-side lens of the aperture stop ST, the path of the light passing through the aperture stop ST can be easily controlled. By setting the Abbe number of the fifth lens 105 closest to the image sensor 300 to be higher than the Abbe number of the first lens 101, the chromatic dispersion of the light passing between the glass lenses can be controlled and guided to the image sensor 300.

[0127] The focal lengths F3 and F4 of the third lens 103 and the fourth lens 104 have positive refractive powers, and the focal lengths F1, F2, and F5 of the first lens 101, the second lens 102, and the fifth lens 105 may have negative refractive powers. Since the lens contracts and expands repeatedly as the temperature changes from low temperature to high temperature, the amount of contraction and expansion can be reduced by a glass lens. When the focal length is expressed as an absolute value, the focal length of the second lens 102 is the largest among the lenses and can be 10 mm or more. The focal length of the third lens 103 is the smallest among the lenses. The difference between the maximum focal length and the minimum focal length can be 5 mm or more. With the focal lengths described above, the optical system can have improved MTF characteristics, aberration control characteristics, resolution characteristics, etc. within the set field of view, and can have good optical performance at the periphery of the field of view.

[0128] As Figure 4 shown, among the lenses of the lens unit 100 in the embodiment, the lens surface of the first lens 101 may include an aspherical surface having an aspherical surface coefficient of 30th order. For example, the first lens 101 may include a lens surface having an aspherical surface coefficient of 30th order. As described above, an aspherical surface having an aspherical surface coefficient (a value other than "0") of 30th order can significantly change the aspherical shape of the peripheral portion, and thus can satisfactorily correct the optical performance of the peripheral portion of the field of view (FOV). As Figure 5 shown, the thicknesses T1 to T5 of the first lens to the fifth lens 101, 102, 103, 104, and 105 and the distances G1 to G4 between two adjacent lenses can be set, and the thicknesses T1 to T5 of each lens can be represented at intervals of 0.1 mm or more in the Y-axis direction orthogonal to the optical axis, and the distances G1 to G4 between each lens can be represented at intervals of 0.1 mm or more.

[0129] As Figure 6 shown, when explaining the Sag values from the optical axis to the ends of the effective regions of the fourth lens and the fifth lens, it can be seen that the absolute values of the Sag values of L4S1 and L4S2, which are the object-side surface and the sensor-side surface of the fourth lens 104, and the Sag value of L5S2, which is the sensor-side surface of the fifth lens 105, are smaller than the Sag value of L5S1, which is the object-side surface of the fifth lens 105. It can be seen that the absolute value of the Sag data of L5S1 is more than twice the absolute values of the Sag data of L4S1, L4S2, and L5S2.

[0130] Figures 7 to 9 is a diagram showing Figure 1 the diffraction MTF (modulation transfer function) in the optical system at room temperature, low temperature, and high temperature, and is a diagram showing the modulation according to the spatial frequency. As Figures 7 to 9As shown, in an embodiment of the present invention, the deviation of MTF at room temperature and low or high temperature can be less than 10%, that is, 7% or less. In Figures 7 to 9 , the x-axis means the defocus position, the y-axis means the MTF, and the graph is measured from F1 to F11 in units of 0.309 mm from 0.000 mm to 3.092 mm.

[0131] Figures 10 to 12 is a graph showing Figure 1 the aberration characteristics of the optical system at room temperature, low temperature, and high temperature. In Figures 10 to 12 the aberration graph of, spherical aberration (longitudinal spherical aberration), astigmatism field curve, and distortion are measured from left to right. In Figures 10 to 12 , the X-axis can represent the focal length (mm) and the degree of distortion (%), and the Y-axis can represent the height of the image. In addition, the graph for spherical aberration is for light in the wavelength bands of about 920 nm, about 940 nm, and about 960 nm, and the graphs for astigmatism and distortion are for light in the wavelength band of about 940 nm. In Figures 10 to 12 the aberration graph of, 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. It can be seen that the optical system 1000 according to the embodiment has measured values close to the Y-axis in almost all regions. That is, the optical system 1000 according to the embodiment has improved resolution, and good optical performance can be achieved not only at the center of the FOV but also at 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 the brightness ratio (modulation) from low temperature to high temperature of is less than 10%, for example, 5% or less, or hardly changes.

[0132] Table 1 compares the changes in optical characteristics such as EFL, BFL, F-number, TTL, and diagonal FOV in the optical system according to the first embodiment at room temperature, low temperature, and high temperature, and it can be seen that based on room temperature, the change rate of the optical characteristics at low temperature is 5% or less, for example, 3% or less, and it can be seen that based on room temperature, the change rate of the optical characteristics at low temperature is 5% or less, for example, 3% or less.

[0133] [Table 1]

[0134] Room temperature Low temperature High temperature Low temperature / Room temperature (%) High temperature / Room temperature (%) EFL 5.169 5.167 5.167 100.04％ 100.00％ BFL 2.000 2.002 2.002 99.90％ 100.00％ F# 2.200 2.2 2.200 100.00％ 100.00％ TTL 12.499 12.502 12.504 99.98％ 100.02％ FOV 72.85 72.85 72.86 100.00％ 100.00％

[0135] Therefore, as shown in Table 1, it can be seen that the change in optical characteristics according to the temperature change from low temperature to high temperature (e.g., the change rates of effective focal length (EFL), TTL, BFL, F-number (F#), and diagonal FOV) is 10% or less, i.e., 5% or less, for example, in the range of 0 to 5%. This means that even when using at least one or two or more aspherical lenses, temperature compensation of the aspherical lenses can be designed to prevent deterioration of the reliability of optical characteristics. In addition, it can be seen that even when the temperature changes from room temperature to low temperature or high temperature, the effective focal length, TTL, BFL, F-number (F#), and diagonal FOV hardly change. The optical system of the embodiment disclosed above can effectively control aberration characteristics such as chromatic aberration and distortion aberration, and can have good optical performance not only at the center of the FOV but also at the periphery.

[0136] The optical system 1000 according to the embodiment disclosed above can satisfy at least one or two or more of the following formulas. Therefore, the optical system 1000 according to the embodiment can have improved optical characteristics. For example, when the optical system 1000 satisfies at least one formula, the optical system 1000 can effectively control aberration characteristics such as chromatic aberration and distortion aberration, and can have good optical performance not only at the center of the FOV but also at the periphery. In addition, the optical system 1000 can have improved resolution. In addition, the thickness of the lens on the optical axis OA and the distance between adjacent lenses on the optical axis OA described in the formula can refer to the embodiment disclosed above.

[0137] [Formula 1] 0.5 < CT1 / CT2 < 1.5

[0138] CT1 means the center thickness of the first lens 101, and CT2 means the center thickness of the second lens 102. Formula 1 sets the difference in the center thicknesses of the first lens and the second lens to be small so that the optical path of the optical system can be easily adjusted. Preferably, 0.8 < CT1 / CT2 < 1.2 can be satisfied. The center thicknesses of the first lens 101 having an aspherical surface and the second lens 102 having a spherical surface can be set so that the optical performance at the center and periphery of the FOV can be improved.

[0139] [Formula 2] (CT5 * CA5) < (CT3 * CA3)

[0140] CT5 is the central thickness of the fifth lens 105, CA5 is the effective diameter of the fifth lens 105, CT3 is the central thickness of the third lens 103, and CA3 is the effective diameter of the third lens. The effective diameter is the average of the effective diameters of the object-side surface and the sensor-side surface of each lens. Preferably, the following condition can be satisfied: CA5 < CA3. By setting the thicknesses and effective diameters of the third lens and the fifth lens, the optical system can improve the aberration.

[0141] [Equation 3] Po1 < 0

[0142] In Equation 3, Po1 means the refractive power of the first lens 101 and can be set to have an effective focal length F similar to the TTL in the optical system for the performance of the optical system. Therefore, TTL > F can be satisfied, and for example, the following condition can be satisfied: 1 < TTL / F < 4.

[0143] [Equation 4] |Po1 * 2| ≤ Po3

[0144] Po3 means the refractive power of the third lens 103 and can be set to be more than twice the refractive power of the first lens 101 for the performance of the optical system. Therefore, the central thickness of the third lens 103 can be increased and the radius of curvature can be decreased, so that the sensitivity of the light passing through the third lens 103 can be reduced. Preferably, |Po1 * 2| < Po3 can be satisfied.

[0145] [Equation 4-1] |Po1 * 2| ≤ Po4

[0146] Po4 means the refractive power of the fourth lens 104 and can be set to be more than twice the refractive power of the first lens 101 for the performance of the optical system. Therefore, the central thickness of the fourth lens 104 can be increased and the radius of curvature can be decreased, so that the sensitivity of the light passing through the fourth lens 104 can be reduced. Preferably, |Po1 * 2| < Po4 can be satisfied.

[0147] [Equation 5] 1.7 ≤ Nd3 < 2.2

[0148] Nd3 is the refractive index of the d-line of the third lens 103. Equation 5 sets the refractive index of the third lens high so that it can control the factors that affect the reduction of the third aberration (Seidel aberration) of the optical system and can reduce the aberration that may occur when the TTL is slightly longer. Equation 5 preferably satisfies: 1.8 ≤ Nd3 ≤ 2.1. If it is designed to be lower than the lower limit of Equation 4, the aberration can be reduced to obtain performance, but the power of the third lens 103 is weakened, making it impossible to collect light efficiently, and the performance of the optical system may deteriorate. If it is designed to be higher than the upper limit of Equation 4, there is a disadvantage that it is difficult to obtain the material. In addition, if the refractive index of the third lens is designed to be lower than the lower limit of Equation 4, the curvature radius of the third lens must be increased to increase the power of the third lens. In this case, lens manufacturing becomes more difficult, the lens failure rate increases, and the yield may decrease.

[0149] [Equation 5-1] 1.7 ≤ Nd4 < 2.2

[0150] Nd4 is the refractive index of the fourth lens 104 at the d-line. Equation 5 can set the refractive index of the fourth lens high. Equation 5-1 can preferably satisfy: 1.8 ≤ Nd4 ≤ 2.1.

[0151] [Equation 5-2] 1.60 ≤ Aver(Nd1:Nd7) ≤ 1.70

[0152] In Equation 5-2, Aver(Nd1:Nd7) is the average value of the refractive index values of the first to fifth lenses at the d-line. When the optical system 1000 according to the embodiment satisfies Equation 5-2, the optical system can set the resolution and suppress the influence on the TTL.

[0153] [Equation 6] 40 < FOV_H < 60

[0154] In Equation 6, FOV_H means 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 6 or fewer lenses including one aspherical lens and at least two or more spherical lenses. Equation 6 preferably satisfies: 45 ≤ FOV_H ≤ 58 or a range of 55 degrees ± 3 degrees. When Equation 6 is satisfied, the change rate of the effective focal length and the change rate of the field of view when the temperature changes from room temperature to high temperature can be set to 5% or less, for example, 0% to 5%. In addition, even when an aspherical lens and a spherical lens are mixed and used in the optical system 1000, the deterioration of the optical characteristics can be prevented by temperature compensation of the glass lens.

[0155] [Equation 7] L1R1 > 0

[0156] L1R1 means the radius of curvature of the first surface S1 of the first lens 101, and can be set to be greater than 0. If Equation 7 is satisfied, the shape of the optical system can be restricted. The object-side surface of the first lens 101 has a shape that bulges toward the driver from the optical axis, and can increase the incident light amount. 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 set the effective diameter of the second lens to be smaller than that of the first lens.

[0157] [Equation 7-1] L2R1 < 0, L3R2 < 0 and L4R2 < 0

[0158] L2R1 is the radius of curvature of the object-side surface of the second lens 102, L3R2 is the radius of curvature of the sensor-side surface of the third lens 103, and L4R2 is the radius of curvature of the sensor-side surface of the fourth lens. Since the first lens has a meniscus shape that bulges toward the object side, and the third lens and the fourth lens have bulging shapes on both sides, the incident light can be refracted from the second lens 102 with the smallest effective diameter to the effective area of the fourth lens with the largest effective diameter. Since the first lens has a meniscus shape that bulges toward the object side, the effective diameter of the lens can be designed to gradually increase from the aperture stop position toward the sensor, thereby reducing the number of lenses. In addition, if the following conditions are satisfied: L1R1 > L1R2 and |L3R1| > L3R2, the effective diameter of the second lens can be designed to be extremely small, and the TTL can be reduced. If the following condition is satisfied: |L3R1| < L3R2, there is a problem of increasing TTL. By setting the radius of curvature of the third lens and the fourth lens to be greater than that of other lenses but less than 20 mm, the influence of the optical characteristics on the incident light can be reduced.

[0159] [Equation 8] 0.5 < BFL / Max_Sag52 to the sensor < 1.5

[0160] The BFL is the distance of the optical axis from the center of the sensor-side surface of the last lens (i.e., the fifth lens) to the surface of the image sensor. The Max_Sag52 to the sensor can be the maximum Sag value of the sensor-side surface of the fifth lens 105, that is, the distance in the optical axis direction from the low point to the image sensor 300. If the optical system satisfies Equation 8, the TTL can be reduced and the conditions for manufacturing the imaging device module can be set. In addition, the Max_Sag52 to the sensor can set the space where the filter 500 and the cover glass 400 located between the image sensor 300 and the fifth lens 105 can be placed. If the range of Equation 8 is less than the lower limit, the space for placing circuit structures such as filters or image sensors becomes limited, and the process of assembling the structure into the optical system may become difficult. If the range of Equation 8 is greater than the upper limit, the process of assembling circuit structures such as filters and image sensors into the optical system is easy, but the TTL becomes longer, making it difficult to miniaturize the optical system. If the sensor-side surface of the last lens does not have a point that protrudes more toward the image sensor than the center of the sensor-side surface between the optical axis and the edge, the Max_Sag52 is 0, and the value of Equation 8 can be equal to the BFL (back focal length).

[0161] [Equation 9] 0.5 < CT1 / CT5 < 1.5

[0162] If Equation 9 is satisfied, the aberration characteristics can be improved and the reduced influence on the optical system can be set. Equation 9 preferably satisfies 0.85 < CT1 / CT5 < 1.25, or CT1 and CT5 can be the same. Equation 9 sets the center thicknesses of the first lens on the object side of the optical system and the fifth lens having a spherical 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 under the set field of view, and the TTL can be controlled.

[0163] [Equation 9-1] 0 < CT1 / CA11 < 0.5

[0164] In Equation 9-1, the center thickness CT1 of the first lens 101 and the effective diameter CA11 of the object-side surface S1 of the first lens 101 can be set, and if these are satisfied, the deterioration of the strength and optical characteristics of the glass lens can be prevented. If it is below the range of Equation 9-1, 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 heavier. Preferably, 0 < CT1 / CA11 < 0.3 can be satisfied.

[0165] [Equation 10] 1 < CT4 / (CT1 + CT2 + CT5) < 2

[0166] CT1, CT2, CT4, and CT5 denote the center thicknesses of the first lens, the second lens, the third lens, and the fifth lens, respectively. When the optical system satisfies Equation 10, the ratio of the center thickness of the thickest fourth lens to the center thicknesses of the thin lenses can be set, and the aberration characteristics can be improved and the influence on the optical system can be set to be reduced. Equation 10 is preferably satisfied as: 1 < CT4 / (CT1 + CT2 + CT5) < 1.5.

[0167] [Equation 11] 1 < CT3 / (CT1 + CT5) < 2.5

[0168] In Equation 11, the center thickness of the third lens 103 can be set to be greater than the sum of the center thicknesses of the first lens and the fifth lens, such that the third lens bulging on both sides can guide light to the entire area of the fourth lens.

[0169] [Equation 12] 4 < CT34 / CT5 < 10

[0170] CT34 is the sum of the center thicknesses of the third lens and the fourth lens. When Equation 12 is satisfied, by arranging the sum of the center thicknesses of the third lens and the fourth lens to exceed the center thickness of the fifth lens 105 by four times, the sensitivity of the light passing through the third lens 103 and the fourth lens 104 can be reduced, and the assemblability of the third lens 103 and the fourth lens 104 can be improved. Preferably, 6 < CT34 / CT5 < 8 can be satisfied.

[0171] [Equation 13] 1 < CA11 / CA21 < 2

[0172] CA11 denotes the effective diameter of the first surface S1 of the first lens 101, and CA21 denotes the effective diameter of the third surface S3 of the second lens 102. When Equation 13 is satisfied, the optical system 1000 can control the incident light and set the factors affecting aberration, and preferably 1 < CA11 / CA31 < 1.6 can be satisfied. Since the first lens and the second lens satisfy Equation 13, the difference in the effective diameters between the first lens and the second lens is not large, such that the influence caused by assembly can be reduced, and the optical influence caused by temperature change can be reduced.

[0173] [Equation 14] 1 < CA52 / CA21 < 3

[0174] CA52 means the effective diameter of the tenth surface S10 of the fifth lens 105, and CA21 means the effective diameter of the third surface S3 of the second lens 102. When Equation 14 is satisfied, the optical system 1000 can control the incident light path and set factors for performance variations according to CRA and temperature. Preferably, Equation 14 can be satisfied as: 1.8 < CA52 / CA21 < 2.5. Equation 14 can set the effective diameters of the object-side surface of the first lens and the sensor-side surface of the last lens of the second lens group.

[0175] [Equation 15] 0 < CA12 / CA21 < 2

[0176] CA12 means the effective diameter of the second surface S2 of the first lens 101, and CA21 means the effective diameter of the third surface S3 of the second lens 102. When the optical system 1000 according to the embodiment satisfies Equation 15, the light traveling 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 can preferably be satisfied as: 0.8 < CA12 / CA21 < 1.5. Since the first lens and the second lens satisfy Equation 15, the sizes for assembling the spherical lens and the aspherical lens can be set.

[0177] [Equation 16] 0 < ΣASL_CT / ΣSSL_CT < 0.5

[0178] ΣASL_CT is the sum of the center thicknesses of the aspherical lenses, such as the center thickness of the first lens. ΣSSL_CT is the sum of the center thicknesses of the spherical lenses, such as the sum of the center thicknesses of the second lens to the fifth lens. If Equation 16 is satisfied, the relationship between the thickness of the aspherical lens and the thickness of the spherical lens compared to TTL can be set to control the overall TTL. Equation 16 in the embodiment is preferably satisfied as: 0 < ΣASL_CT / ΣSSL_CT < 0.2.

[0179] [Equation 17] 0 < ΣASL_CT / TD < 0.2

[0180] 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 fifth lens. Equation 17 can set the relationship between the sum of the center thicknesses of the aspherical lenses of the optical system and the maximum optical axis distance between the lenses. Equation 17 is preferably satisfied as: 0 < ΣASL_CT / TD < 0.1.

[0181] [Equation 18] 0.2 < ΣSSL_CT / TD < 0.7

[0182] Equation 18 can set the relationship between the sum of the central thicknesses of the spherical lenses of the optical system and the maximum distance along the optical axis between the lenses. Preferably, 0.4 ≤ ΣSSL_CT / TD < 0.6 can be satisfied.

[0183] [Equation 19] 0.1 < ΣSSL_CT / TTL < 0.6

[0184] Equation 19 can set the relationship between the sum of the central thicknesses of the spherical lenses and the total optical length (TTL). Equation 19 can preferably satisfy: 0.3 ≤ ΣSSL_CT / TTL ≤ 0.5.

[0185] [Equation 20] 1 < SSL_CA_Aver / ASL_CA_Aver < 2

[0186] SSL_CA_Aver means the average effective diameter of the glass lens having a spherical surface, and ASL_CA_Aver means the average effective diameter of the glass molded lens having an aspherical surface. By setting the effective diameters of the spherical lens and the aspherical lens in Equation 20, the path of the incident light can be effectively guided. Equation 20 can preferably satisfy: 1 < SSL_CA_Aver / ASL_CA_Aver < 1.5. The embodiment can reduce the number of lenses and prevent deterioration of optical characteristics by mixing spherical lenses and aspherical lenses within the optical system.

[0187] [Equation 21] 0 < SSL_Nd_Aver / ASL_Nd_Aver < 1.60

[0188] SSL_Nd_Aver is the average refractive index of the spherical lens, and ASL_Nd_Aver is the average refractive index of the aspherical lens. Preferably, the refractive index of the spherical lens and the refractive index of the aspherical lens can be set to satisfy the following condition: 1 < SSL_Nd_Aver / ASL_Nd_Aver < 1.3.

[0189] [Equation 21-1] ΣASL_Nd < ΣSSL_Nd

[0190] ΣASL_Nd is the sum of the refractive indices of the aspherical lenses, and ΣSSL_Nd is the sum of the refractive indices of the spherical lenses. The optical system can adjust the resolution and dispersion by setting the sum of the refractive indices of the spherical lenses to be higher than the sum of the refractive indices of the object-side aspherical lenses.

[0191] [Equation 22] (CG1 + CG2) < CT3

[0192] 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 Equation 22, the TTL can be adjusted by increasing the center thickness of the third lens and decreasing the center distance between the first lens and the third lens. Here, the following conditions can be satisfied: (CT1 * 2) < CG2 or (CT2 * 2) < CG2.

[0193] [Equation 23] 0.20 < LD12 / LD35 < 0.50

[0194] LD12 is the optical axis distance between two lenses adjacent to the object, for example, the optical axis distance from the center of the object-side surface of the first lens 101 to the center of the sensor-side surface of the second lens 102. LD35 is the optical axis distance of three lenses adjacent to the sensor, and is the optical axis distance from the center of the object-side surface of the third lens 103 to the center of the sensor-side surface of the fifth lens 105. In Equation 23, the optical axis distance of the lenses 101 and 102 arranged on the object side is made small, and the optical axis distance of the lenses 103, 104, and 105 arranged on the sensor side is made large, so that the distortion and chromatic aberration caused by the first lens 101 and the second lens 102 can be corrected. Preferably, the optical axis distance from the object-side surface of the first lens 101 to the sensor-side surface of the second lens 102 can be set to 26% or more and 36% or less of the optical axis distance from the object-side surface of the third lens 103 to the sensor-side surface of the fifth lens 105. Since Equation 23 is satisfied, the aberration and distortion that may occur in an optical system with a small TTL can be reduced. That is, it can be satisfied that: 0.26 ≤ LD12 / LD35 ≤ 0.36.

[0195] [Equation 24] 0 < LD12 / TTL < 0.3

[0196] In Equation 24, by setting the optical axis distance of the two lenses on the object side with respect to the total length (TTL), the effective diameter, radius of curvature, refractive index, Abbe number, etc. of the glass lens can be set. Preferably, it can be satisfied that: 0.11 ≤ LD12 / TTL ≤ 0.23.

[0197] [Equation 25] 0 < CT4 / TTL < 0.3

[0198] In Equation 25, by setting the center thickness of the fourth lens within the above range based on the TTL, the light rays incident through the first lens to the third lens can be refracted to the entire area of the fifth lens, and the chromatic aberration of the optical system can be improved.

[0199] [Equation 25-1] 0.4 < CT4 / ImgH < 0.9

[0200] In Equation 25-1, by setting the center thickness of the third lens within the above range with respect to ImgH, changes in optical characteristics due to temperature variations can be reduced.

[0201] [Equation 26] 0 < |L2R1 / L5R2| < 1

[0202] L2R1 is the radius of curvature of the third surface of the second lens, and L5R2 is the radius of curvature of the tenth surface of the fifth lens. In Equation 26, the radii of curvature of the object side surface of the second lens and the sensor side surface of the fifth lens can be set to control the focal power of the second lens and the fifth lens. Therefore, good optical performance can be achieved at the center and periphery of the field of view. Preferably, Equation 26 can satisfy: 0 < |L2R1 / L5R2| < 0.5.

[0203] [Equation 27] 3 < |L5R1 / CT5| < 10

[0204] L5R1 means the radius of curvature of the object side surface of the fifth lens. When Equation 27 is satisfied, the focal power of the fourth lens can be controlled to control the incident light as an aspherical lens, and deterioration of the aspherical component can be prevented. Preferably, 6 ≤ |L5R1 / CT5| < 9 can be satisfied.

[0205] [Equation 28] 1.2 < |L3R1 / L3R2| < 5

[0206] L3R1 is the radius of curvature of the object side surface of the third lens, and L3R2 is the radius of curvature of the sensor side surface of the third lens. If Equation 28 is satisfied, the sensitivity of light can be reduced by adjusting the radius of curvature of the lens located at the center of the optical system. Preferably, 2 ≤ |L3R1 / L3R2| < 2.5 can be satisfied.

[0207] [Equation 29] 0.5 < |L4R1 / L4R2| < 1.5

[0208] L4R1 is the radius of curvature of the object side surface of the fourth lens, and L4R2 is the radius of curvature of the sensor side surface of the fourth lens. If Equation 29 is satisfied, the sensitivity of light can be reduced by adjusting the radius of curvature of the lens located at the center of the optical system. Preferably, |L4R1 / L4R2| = 1 can be satisfied.

[0209] [Equation 30] |S7SagD1| - |S8SagD1| < 0.2 mm

[0210] S7SagD1 is the Sag value at a first distance D1 from the optical axis on the seventh surface S7 of the fourth lens 104, and S8SagD1 is the Sag value at the first distance D1 from the optical axis on the eighth surface S8 of the fourth lens 104. That is to say, the fourth lens 104 can have a difference of less than 0.2 mm between the Sag values of the seventh surface and the eighth surface S8 at a point spaced apart from the optical axis by the first distance D1. The first distance D1 is a point at half of the average effective radius of the fourth lens 104 based on the optical axis. Here, S7SagD1 > 0 and S8SagD1 < 0.

[0211] [Equation 31] 0.5 < SD / TD < 1

[0212] SD is the optical axis distance from the aperture stop to the center of the sensor side surface of the last lens, and TD is the optical axis distance from the center of the object side surface of the first lens to the center of the sensor side surface of the last lens. In other words, the relationship between the position of the aperture stop and the maximum distance between the entire lenses can be set. Preferably, 0.8 < SD / TD < 0.95 can be satisfied.

[0213] [Equation 32] 0.5 < CT_Max / CG_Max < 1.5

[0214] In Equation 32, the maximum center thickness CT_Max in the lens and the maximum center spacing CG_Max between adjacent lenses can be set. When Equation 32 is satisfied, the optical system can have good optical performance at the focal length under the set field of view, and the TTL can be reduced. Preferably, the embodiment can satisfy: 0.8 < CT_Max / CG_Max < 1.2.

[0215] [Equation 33] 1 < ΣCT / ΣCG < 5

[0216] In Equation 33, ΣCT is the sum of the center thicknesses of the lenses, and ΣCG is the sum of the center spacings between adjacent lenses. When Equation 33 is satisfied, the optical system can have good optical performance at the focal length under the set field of view, and the TTL can be reduced. Preferably, the embodiment can satisfy 1 < ΣCT / ΣCG < 1.5.

[0217] [Equation 34] 6 < ΣNd < 11

[0218] ΣNd means the sum of the refractive indices of each d-line among the d-lines of multiple lenses. If Equation 34 is satisfied, the optical system 1000 in which an aspherical lens and a spherical lens are mixed can control the TTL and can have improved resolution. In addition, by arranging a glass lens with a relatively high refractive index and a thick thickness at the center, the TTL and the refractive index can be set. Equation 34 preferably satisfies: 6 ≤ ΣNd ≤ 10.

[0219] [Equation 35] 10 < ΣAbbe / ΣNd < 50

[0220] ΣAbbe means the sum of the Abbe numbers of each lens among a plurality of lenses. When Equation 35 is satisfied, the optical system 1000 can have improved aberration characteristics and resolution. Equation 35 sets the sum of the Abbe numbers and the sum of the refractive indices of the lenses, thereby controlling the optical characteristics, and preferably satisfies: 28 < ΣAbbe / ΣNd < 40.

[0221] [Equation 36] 0.5 < CA11 / CA_Min < 2.5

[0222] CA11 is the effective diameter of the object side surface of the first lens, and CA_Min means the minimum effective diameter among the object side surface and the sensor side surface of the lens. If Equation 36 is satisfied, the optical system can provide a thinner module while maintaining incident light control and optical performance. Equation 36 preferably satisfies: 1 < CA11 / CA_Min < 2.

[0223] [Equation 37] 1 < CA_Max / CA_Min < 5

[0224] 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 set the size for a thin and compact structure while maintaining optical performance. Equation 37 preferably satisfies: 2 < CA_Max / CA_Min < 2.5.

[0225] [Equation 38] 1 < CA_Max / CA_Aver < 3

[0226] CA_Aver means the average value 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 set the size for a thin and compact structure while maintaining optical performance. Equation 38 preferably satisfies: 1 < CA_Max / CA_Aver < 1.5.

[0227] [Equation 39] 20 < CA_Max * nL < 32

[0228] nL is the number of lenses of the optical system and can be, for example, 5. If Equation 39 is satisfied, the optical system can set the maximum effective diameter according to the total number of lenses. Equation 39 preferably satisfies: 25 < CA_Max * nL < 30.

[0229] [Equation 40] 0.5 < CA_Max / (2 * ImgH) < 2

[0230] Equation 40 can set the maximum effective diameter CA_Max of the lens surface and the diagonal length of the image sensor, and if this condition is met, the optical system can maintain good optical performance and be sized for a thin and compact structure. Preferably, 0.6 < CA_Max / (2*ImgH) < 1 can be satisfied.

[0231] [Equation 41] 0.5 < TD / CA_Max < 4

[0232] If Equation 41 is satisfied, the total optical axis distance and the maximum effective diameter of the lens can be set, and a size for good optical performance can be set. Equation 41 can preferably satisfy: 1.5 < TD / CA_Max < 2.2.

[0233] [Equation 42] 0 < TD / CA_Max < 0.7

[0234] 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 ≤ TD / CT_Max ≤ 0.3 can be satisfied.

[0235] [Equation 43] 0 < F / CA51 < 1.5

[0236] F means the effective focal length (EFL) of the optical system and 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 can be set, and the influence on the reduction of the optical system, such as TTL, can be controlled. Equation 43 can preferably satisfy: 0.8 < F / CA51 < 1.2.

[0237] [Equation 44] 0 < F / L1R1 < 2

[0238] 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: 1 < F / L1R1 < 1.5.

[0239] [Equation 45] 0.5 < Max(CT / ET) < 1.5

[0240] 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 preferably satisfies: 0.8 < Max(CT / ET) < 1.2.

[0241] To describe the ratio of the center thickness to the edge thickness of the spherical lens and the aspherical lens within the lens unit, the following condition can be satisfied: Max_SSL(CT / ET) > Max_ASL(CT / ET). Max_SSL(CT / ET) means the maximum ratio of the center thickness to the edge thickness in the spherical lens, and Max_ASL(CT / ET) can mean the maximum ratio of the center thickness to the edge thickness in the aspherical lens.

[0242] [Equation 46] 0 < EPD / L1R1 < 1

[0243] 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 can preferably be satisfied: 0.5 < EPD / L1R1 < 0.8.

[0244] [Equation 47] 1 < |F1 / F3| < 4

[0245] F1 is the focal length of the first lens, and F3 is the focal length of the third lens. If Equation 47 is satisfied, the powers 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, 2 ≤ F1 / F3 ≤ 2.7 can be satisfied.

[0246] [Equation 47-1] |F1| > F4

[0247] [Equation 47-2] |F1| > F3

[0248] [Equation 47-3] |F1| < |F2|

[0249] [Equation 47-4] F < F4 < |F1|

[0250] [Equation 47-5] F < F4 < |F5|

[0251] In Equations 47-1 to 47-5, F1 is the focal length of the first lens, F2 is the focal length of the second lens, F3 is the focal length of the third lens, F4 is the focal length of the fourth lens, and F5 is the focal length of the fifth lens. The power of each lens can be controlled to guide the light from the aspherical lens through the spherical lens. The aperture stop ST is disposed on the sensor-side surface of the first lenses 101 and 112. The focal length of the lens that is closer to the sensor than the aperture stop ST and closest to the aperture stop ST is less than 0. In an embodiment of the present invention, the focal length F2 of the second lens 102 should be designed to be less than 0. In this case, since the second lens 102 has a convex meniscus shape facing the sensor, the radius of curvature of the object-side surface of the third lens 103 can be increased. Since the third lens 103 has a positive power, the effective diameters of the third lens and the fourth lens can be increased.

[0252] The combined focal length F25 of the second lens to the fifth lens may have a positive refractive power. That is, the lens closer to the sensor than the aperture stop ST, i.e., the combined focal length F25 of the lens 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 a horizontal field of view FOV_H of 45 degrees to 60 degrees.

[0253] [Equation 48] |Po5| < Po4 < Po3

[0254] Po3 is the refractive power value of the third lens, Po4 is the refractive power value of the fourth lens, and Po5 is the refractive power value of the fifth lens. The refractive powers of the third lens and the fourth lens are positive, and the refractive power of the fifth lens is negative. Therefore, the fifth lens can compensate for the aberration that appears in the third lens and the fourth lens.

[0255] [Equation 49] 15 < Vd2 - Vd3 < 60

[0256] In Equation 49, Vd2 is the Abbe number of the second lens, and Vd3 is the Abbe number of the third lens. If Equation 49 is satisfied, the difference in Abbe numbers between two adjacent lenses can be maintained above a certain value, and chromatic aberration can be improved. Equation 49 is preferably satisfied: 20 < Vd2 - Vd3 < 40.

[0257] [Equation 50] 0 < |F25 / F12| < 2

[0258] In Equation 50, the relationship between the combined focal length F12 of the first lens and the second lens and the combined focal length F25 of the third lens to the fifth lens is set so that the refractive powers of the first lens group and the second lens group can be controlled to improve the resolution, and the optical system can be provided in a thin and compact size. Equation 50 is preferably satisfied: 0 < |F25 / F12| < 1.

[0259] [Equation 51] 0 < |F25 / F| < 2

[0260] In Equation 51, the relationship between the total focal length F and the combined focal length F25 of the second lens to the fifth lens is set so that the resolution can be improved by controlling the refractive power of each lens. Equation 51 is preferably satisfied: 0.5 < |F25 / F| < 1

[0261] [Equation 52] 0 < |F35 / F12| < 2

[0262] In Equation 52, the relationship between the combined focal length F12 of the first lens and the second lens and the combined focal length F35 of the third lens to the fifth lens is set such that the combined focal length of the two lenses with a small effective diameter and the combined focal length of the three lenses with a large effective diameter are set within the above ranges, so that the resolution can be improved by controlling the combined diopter of each lens. Equation 52 preferably satisfies: 0 < |F35 / F12| < 1 and F35 > 0, F12 < 0.

[0263] [Equation 53] |F_SSL_Aver| < |F_ASL_Aver|

[0264] In Equation 53, F_SSL_Aver is the average value of the focal lengths of the spherical lenses, and F_ASL_Aver is the average value of the focal lengths of the aspherical lenses. If Equation 53 is satisfied, the chromatic aberration and distortion aberration can be improved by combining the spherical lenses and the aspherical lenses.

[0265] [Equation 54] 0 < nASL / nL < 0.5

[0266] nASL is the number of aspherical lenses, and nL means the total number of lenses. By arranging the number of aspherical lenses in Equation 54 to be less than 0.5 times the total number of lenses, the thickness of the optical system can be reduced, and more diverse diopters can be provided by the aspherical lenses. Additionally, Equation 54-1 can be satisfied: 0.5 < nSSL / nL < 1, where nSSL is the number of glass lenses.

[0267] [Equation 55] 0.70 < DL3S / TTL < 0.90

[0268] DL3S is the distance from the center of the object-side surface of the third lens to the optical axis of the image sensor. By setting the center thicknesses of the third lens and the fourth lens to be thick and increasing the center distance between the third lens and the fifth lens to set DL3S within the above range with respect to the length of TTL, the optical system can be designed to guide light without aberration and distortion. Preferably, 0.75 ≤ DL3S / TTL ≤ 0.85 can be satisfied. That is, for the distance from the center of the object-side surface of the third lens to the optical axis of the image sensor, DL3S can be set within the range of 75% to 85% of TTL.

[0269] [Equation 56] 5 mm < TTL < 20 mm

[0270] TTL (total track length) means the distance on the optical axis OA from the center of the first surface S1 of the first lens 101 to the surface of the image sensor 300. In Equation 56, a vehicle optical system can be provided by setting TTL to 15 mm or less. Preferably, 10 mm ≤ TTL ≤ 15 mm can be satisfied.

[0271] [Formula 57] 2mm < ImgH

[0272] Formula 57 can set 1 / 2 of the diagonal length of the image sensor 300 and can provide an optical system with the size of a vehicle sensor. Formula 57 preferably satisfies: 2.8mm ≤ ImgH < 5mm.

[0273] [Formula 58] 1mm < BFL < 3mm

[0274] In Formula 58, the BFL (back focal length) is set to be greater than 1mm and less than 3mm, thereby ensuring the installation space for the filter 500 and the cover glass 400, improving the assemblability of components through the distance between the image sensor 300 and the last lens, and improving the bonding reliability. Formula 58 preferably satisfies: 1.5mm ≤ BFL ≤ 2.8mm. If the BFL is less than the range of Formula 58, some of the light traveling to the image sensor may not be transmitted to the image sensor, which may lead to a reduction in resolution. If the BFL exceeds the range of Formula 58, stray light may be introduced, which may deteriorate the aberration characteristics of the optical system.

[0275] [Formula 59] 1 < BFL / CG2 < 3

[0276] In Formula 59, the BFL (back focal length) and the center distance CG4 between the fourth lens and the fifth lens can be set, thereby improving the bonding reliability of components according to the installation space of the filter 500 and the cover glass 400 and the distance between the glass lenses adjacent to the sensor. In Formula 59, it can be satisfied that: 1.2 ≤ BFL / CG4 ≤ 1.5. The center distance CG4 between the fourth lens and the fifth lens can be the largest within the lens unit.

[0277] [Formula 60] 0 < CT3 / BFL < 1

[0278] By setting the BFL (back focal length) in Formula 60 to be greater than the center thickness of the first lens, the installation space for the filter 500 and the glass cover 400 can be ensured, and the assembly of components can be improved through the distance between the image sensor 300 and the last lens, and the bonding reliability can be improved. If the BFL does not satisfy Formula 60, some of the emitted light may not be transmitted to the effective area of the image sensor, thereby reducing the resolution. Preferably, it can be satisfied that 0.5 < CT1 / BFL ≤ 0.9.

[0279] [Formula 61] F < 15mm

[0280] Formula 61 can set the total effective focal length F suitable for the vehicle optical system. Formula 61 can satisfy the range of 1mm ≤ F ≤ 10mm or 3mm ≤ F ≤ 8mm.

[0281] [Equation 62] 45 degrees < FOV < 75 degrees

[0282] In Equation 62, FOV (field of view) means the field of view (degrees) in the diagonal direction of the optical system 1000, and a vehicle optical system with less than 75 degrees can be provided. Preferably, 55 degrees ≤ FOV ≤ 74 degrees can be satisfied.

[0283] [Equation 63] 1 < TTL / CA_Max < 3

[0284] CA_Max means the maximum effective diameter (mm) of the object-side surface and the sensor-side surface of a plurality of lenses. Equation 63 sets the relationship between the total optical axis length and the maximum effective diameter of the optical system, and a thin vehicle optical system can be provided. Equation 63 can preferably satisfy: 2 < TTL / CA_Max ≤ 2.5.

[0285] [Equation 64] 3 < TTL / ImgH < 5

[0286] Equation 64 can set the total optical axis length (TTL) of the optical system and the diagonal length (ImgH) from the optical axis of the image sensor 300. When the optical system 1000 according to the embodiment satisfies Equation 64, the optical system 1000 can have a size of ImgH larger than TTL to be applied to the vehicle image sensor 300, thereby providing improved image quality. Equation 64 can preferably satisfy: 3.5 ≤ TTL / ImgH ≤ 4.5.

[0287] [Equation 65] 0.1 < BFL / ImgH < 1.5

[0288] Equation 65 can set the optical axis distance between the image sensor 300 and the last lens and the diagonal length from the optical axis of the image sensor 300. When the optical system 1000 according to the embodiment satisfies Equation 65, the optical system 1000 can ensure the BFL (back focal length) for 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 field of view (FOV). Equation 65 is preferably 0.5 < BFL / ImgH < 1, and the following condition can be satisfied: BFL < ImgH.

[0289] [Equation 66] 1 < TTL / BFL < 10

[0290] 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: 3 ≤ TTL / BFL < 5.

[0291] [Equation 67] 1 < TTL / F < 3

[0292] 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: 2 ≤ TTL / F < 2.8. 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 lower than the lower limit of Equation 67, it is necessary to increase the dioptric power of the lens, making it difficult to correct spherical aberration or distortion aberration. If it is higher than the upper limit of Equation 67, the effective diameter or TTL of the lens becomes longer, which may cause a problem that the imaging lens system becomes larger.

[0293] [Equation 68] 1 < F / BFL < 10

[0294] Equation 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. When the optical system 1000 according to the embodiment satisfies Equation 68, the optical system 1000 can have a set field of view and an appropriate focal length, and can provide a vehicle optical system. 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. Equation 68 can preferably satisfy: 1.5 < F / BFL < 2.5.

[0295] [Equation 69] 1 < F / ImgH < 5

[0296] Equation 69 can set the total effective focal length F of the optical system 1000 and the diagonal length (ImgH) of the image sensor 300 from the optical axis. The optical system 1000 can have improved aberration characteristics in the size of the vehicle image sensor 300. Equation 69 can preferably satisfy: 1.2 < F / ImgH < 2.

[0297] [Equation 70] 1 < F / EPD < 5

[0298] Equation 70 can set the total effective focal length F and the entrance pupil diameter of the optical system 1000. Therefore, the total brightness of the optical system can be controlled. Equation 70 can preferably be set such that: 1 < F / EPD < 3.

[0299] [Equation 71] 0 < BFL / TD < 0.5

[0300] Equation 71 can set the relationship between the optical axis distance TD of the lens of the optical system 1000 and the back focal length BFL. Therefore, the resolution of the optical system can be maintained, and the total size can be controlled. Equation 71 preferably satisfies: 0.2 ≤ BFL / TD < 0.3. If the following conditional value of BFL / TD exceeds 0.5, then compared with TD, BFL is designed to be large, so the size of the entire optical system becomes large, making it difficult to miniaturize the optical system, and the distance between the fifth lens and the image sensor becomes long, such that unnecessary light amount may be increased between the fifth lens and the image sensor, resulting in problems of reducing the resolution, such as deterioration of aberration characteristics.

[0301] [Equation 72] 0 < EPD / ImgH / FOV < 0.2

[0302] Equation 72 can set the relationship between the size of the entrance pupil diameter (EPD), half of the diagonal length (ImgH) of the image sensor, and the diagonal field of view. Therefore, the total size and brightness of the optical system can be controlled. Equation 72 can preferably satisfy: 0 < EPD / ImgH / FOV < 0.1.

[0303] [Equation 73] 20 < FOV / F# < 40

[0304] Equation 73 can set the relationship between the diagonal field of view of the optical system and the F-number. Equation 73 can preferably satisfy: 30 < FOV / F# < 36. Here, F# is set to 2.3 or less to provide a bright image.

[0305] [Equation 74] 15 < ΣSSL_CT * nSSL < 22

[0306] Equation 74 can set the center thickness and number of spherical lenses through the product of the sum of the center thicknesses ΣSSL_CT of the spherical lenses and the number nSSL of spherical lenses. Preferably, Equation 74 can satisfy: 16 ≤ ΣGL_SST * nSSL ≤ 20.

[0307] [Equation 75] 0 < ΣASL_CT * nASL < 1

[0308] Equation 75 can set the center thickness and number of aspherical lenses by the product of the sum of the center thicknesses of the aspherical lenses ΣASL_CT and the number of aspherical lenses nASL. Preferably, Equation 75 can satisfy: 0.4 ≤ ΣASL_CT * nASL ≤ 0.6.

[0309] [Equation 76] 40 < TTL * nSSL < 60

[0310] Equation 76 can set TTL and the number of spherical lenses, and can control dispersion and refraction angle by spherical lenses in an optical system with a TTL of 15 mm or less.

[0311] [Equation 77] 8 < ImgH * nSSL < 16

[0312] Equation 77 can set ImgH and the number of spherical lenses, and can control dispersion and refraction angle by spherical lenses in an optical system with an ImgH of less than 5 mm.

[0313] [Equation 78] |Max_Sag42| < |Max_Sag51|

[0314] Max_Sag42 is the maximum distance 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 in the optical axis direction, and Max_Sag51 is the maximum distance from a straight line perpendicular to the optical axis on the object side surface of the fifth lens to the object side surface of the fifth lens in the optical axis direction. When Equation 78 is satisfied, the radius of curvature of the lens surface of the spherical lens can be adjusted to guide light to the entire area of the image sensor, and the effective diameters of the fourth lens and the fifth lens can be adjusted.

[0315] [Equation 79] |Max_Sag52| < |Max_Sag51|

[0316] Max_Sag52 is the maximum distance from a straight line perpendicular to the optical axis on the sensor side surface of the fifth lens to the sensor side surface of the fifth lens in the optical axis direction. When Equation 79 is satisfied, the effective diameter of the fifth lens can be controlled by adjusting the radii of curvature of the object side surface and the sensor side surface of the fifth lens. Here, Max_Sag52, Max_Sag51 < 0.

[0317] [Equation 80]

[0318]

[0319] In Equation 80, Z can mean Sag, which can be the distance from an arbitrary position on the aspherical surface to the vertex of the aspherical surface in the optical axis direction. Y can be the distance from an arbitrary position on the aspherical surface to the optical axis in a direction perpendicular to the optical axis. c can be the curvature of the lens, and K can be the conic constant. Additionally, A, B, C, D, E, and F can be the aspherical coefficients.

[0320] The optical system 1000 according to an embodiment can satisfy at least one or two or more of Equations 1 to 40. At least one or more of Equations 1 to 40 can satisfy at least one or more of Equations 41 to 79. In this case, the optical system 1000 can have improved optical characteristics. Specifically, when the optical system 1000 satisfies at least one of Equations 1 to 40 and / or at least one of Equations 41 to 79, the optical system 1000 can have improved resolution, and can improve aberration and distortion characteristics. Additionally, the optical system 1000 can ensure the BFL for applying the vehicle image sensor 300, compensate for the deterioration of optical characteristics due to temperature changes, and minimize the distance between the last lens and the image sensor 300, thereby having good optical performance at the center and periphery of the FOV.

[0321] Table 2 shows the terms of the above equations in the optical system 1000 according to an embodiment, including the TTL (mm), BFL, effective focal length F (mm), ImgH (mm), effective diameter CA (mm), optical axis distance TD (mm) from the first surface S1 to the tenth surface S10, the focal lengths F1, F2, F3, F4, and F5 (mm) of each of the first lens to the fifth lens, the sum of refractive indices, the sum of Abbe numbers, the sum of the center thicknesses (mm) of each lens, the sum of the distances between adjacent lenses, the diagonal FOV (degrees), the edge thickness ET, the focal lengths of the first lens group and the second lens group, the combined focal length of the second lens to the fourth lens, the F number, etc.

[0322] [Table 2]

[0323] Item Embodiment Item Embodiment F 5.167 ET1 1.792 F1 -12.155 ET2 1.218 F2 -14.025 ET3 1.850 F3 5.075 ET4 2.690 F4 7.756 ET5 1.085 F5 5.167 F# 2.20 F_LG1 -12.155 FOV (diagonal) 72.866 F_LG2 4.269 EPD 2.359 F12 -6.458 BFL 2.650 F34 3.689 TD 9.850 F35 3.660 ImgH 3.092 ∑Nd 8.200 SD 8.479 ∑Abbe 274.34 TTL 12.500 ∑CT 5.212 ∑ET 8.6345 ∑CG 4.638

[0324] Table 3 shows the result values of the above Equations 1 to 40 in the optical system 1000 according to an 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 Equations 1 to 40. Specifically, it can be seen that the optical system 1000 according to an embodiment satisfies all of Equations 1 to 40. Therefore, the optical system 1000 can have good optical performance at the center and periphery of the field of view (FOV), and can have excellent optical characteristics.

[0325] [Table 3]

[0326]

[0327]

[0328] Table 4 shows the resulting values of the above equations 41 to 79 in the optical system 1000 of the 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 the equations 41 to 79. Specifically, it can be seen that the optical system 1000 according to the embodiment satisfies all of the equations 41 to 79. Therefore, the optical system 1000 can have good optical performance at the center and periphery of the FOV and can have excellent optical characteristics.

[0329] [Table 4]

[0330]

[0331]

[0332]

[0333] Figure 13 is an example of a plan view of a vehicle to which a camera device module or an optical system according to an embodiment of the present invention is applied. Referring to Figure 13 , a vehicle camera device system according to an embodiment of the present invention includes an image generation unit 11, a first information generation unit 12, second information generation units 21, 22, 23, 24, 25, and 26, and a control unit 14. The image generation unit 11 may include at least one camera device module 31 provided in the vehicle and may capture an image of the front of the vehicle and / or the driver to generate an image of the front or inside of the vehicle. The image generation unit 11 may use the camera device module 31 to capture images of the front of the vehicle and around the vehicle in one or more directions to generate an image of 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 generation unit 11 provides the driver image, the front image, and the surrounding image to the control unit 14. Next, the first information generation unit 12 may include at least one radar and / or camera device placed in its own vehicle and may detect the front of its own vehicle to generate first detection information. Specifically, the first information generation unit 12 is placed in its own vehicle and detects the position and speed of the vehicle located in front of its own vehicle, the presence of pedestrians, and the position, etc., to generate first detection information.

[0334] Using the first detection information generated by the first information generation unit 12, the distance between the host vehicle and the vehicle ahead can be controlled to be maintained at a constant level, and the stability of vehicle operation can be increased in preset specific situations (for example, when the driver wants to change the driving lane of the host vehicle or when reverse parking). The first information generation unit 12 provides the first detection information to the control unit 14. The second information generation units 21, 22, 23, 24, 25, and 26 detect each side of the host vehicle based on the front image generated by the image generation unit 11 and the first detection information generated by the first information generation unit 12 to generate second detection information. Specifically, the second information generation units 21, 22, 23, 24, 25, and 26 may include at least one radar and / or camera device provided on the host vehicle, and may detect the position and speed of the vehicle located on the side of the host vehicle or capture an image. Here, the second information generation units 21, 22, 23, 24, 25, and 26 may be provided at each of the front corners, side mirrors, and rear center and rear corners of the host vehicle.

[0335] At least one information generation unit of these vehicle camera device systems may be equipped with an optical system and a camera device module having the optical system as described in the above embodiment, and may provide the user with the information obtained through the front, rear, each side, or corner area of the vehicle or process the information to achieve autonomous driving or protect the safety of the vehicle and surrounding objects. The optical system of the camera device module according to an embodiment of the present invention may be installed in a plurality of units in the vehicle to enhance safety adjustment, autonomous driving functions, and increase convenience by using an advanced driver assistance system (ADAS). In addition, the optical system of the camera device module is applied to the vehicle as a control component such as a lane keeping assist system (LKAS), a lane departure warning system (LDWS), and a driver monitoring system (DMS). Such a vehicle camera device module can achieve stable optical performance even under changing environmental temperatures and can provide a module with price competitiveness, thereby ensuring the reliability of vehicle components.

[0336] The features, structures, effects, etc. described in the embodiments are included in at least one embodiment of the present invention and are not necessarily limited to one embodiment. In addition, the features, structures, effects, etc. shown in each embodiment can be combined or modified by those of ordinary skill in the art to which the embodiments pertain for other embodiments. Therefore, the content related to such combinations and modifications should be construed as being included within the scope of the present invention. Additionally, although the embodiments have been described above, this is merely an example and does not limit the present invention, and the above has illustrated the embodiments to those of ordinary skill in the art to which the present invention pertains without departing from the essential features of the embodiments. It can be seen that various modifications and applications that have not been made are possible. For example, each component specifically shown in the embodiments can be implemented by modification. And the differences related to these modifications and applications should be construed as being included within the scope of the present invention defined in the appended claims.

Claims

1. An optical system, comprising: a first lens, a second lens, a third lens, a fourth lens, and a fifth lens sequentially arranged from the object side, wherein the combined focal power of the first lens and the second lens is negative, wherein the combined focal power of the third lens to the fifth lens is positive, wherein, among the effective diameters of the first lens to the fifth lens, the effective diameter of the second lens is the smallest, wherein the effective diameter of the first lens is greater than the effective diameter of the second lens and less than the effective diameters of the third lens to the fifth lens, wherein, among the focal powers of the first lens to the fifth lens, the focal power of the third lens is the largest, and wherein, among the focal powers of the first lens to the fifth lens, the focal power of the fourth lens is the second largest.

2. An optical system, comprising: a first lens, a second lens, a third lens, a fourth lens, and a fifth lens sequentially arranged from the object side, wherein the combined focal power of the first lens and the second lens is negative, wherein the combined focal power of the third lens to the fifth lens is positive, wherein, among the effective diameters of the first lens to the fifth lens, the effective diameter of the second lens is the smallest, wherein, among the focal powers of the first lens to the fifth lens, the focal power of the third lens is the largest, and wherein the optical axis distance from the object-side surface of the first lens to the sensor-side surface of the second lens is in the range of 26% to 36% of the optical axis distance from the object-side surface of the third lens to the sensor-side surface of the fifth lens.

3. An optical system, comprising: a first lens, a second lens, a third lens, a fourth lens, and a fifth lens sequentially arranged from the object side; and an aperture stop disposed on the periphery between the first lens and the second lens, wherein, among the effective diameters of the first lens to the fifth lens, the effective diameter of the second lens is the smallest, wherein the focal power of the third lens is positive and is the largest among the focal powers of the first lens to the fifth lens, and wherein the focal power of the fourth lens is positive and is greater than the focal powers of the first lens, the second lens, and the fifth lens.

4. The optical system according to any one of claims 1 to 3, comprising: an image sensor, wherein the radii of curvature of the object-side surface and the sensor-side surface of the fourth lens are the same, wherein, among the central thicknesses of the first lens to the fifth lens, the central thickness of the fourth lens is the thickest.

5. The optical system according to any one of claims 1 to 3, wherein, the central distance between the third lens and the fourth lens is greater than the central distance between the first lens and the second lens and the central distance between the second lens and the third lens.

6. The optical system according to any one of claims 1 to 3, wherein, the central distance between the fourth lens and the fifth lens is the largest among the central distances between the first lens to the fifth lens. Among them, the first lens to the fifth lens are arranged to be spaced apart from each other along the optical axis.

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

8. The optical system according to any one of claims 1 to 3, comprising: an image sensor, wherein, the optical axis distance from the object side surface of the third lens to the image sensor provided on the sensor side of the fifth lens is in the range of 75% to 85% of the optical axis distance from the object side surface of the first lens to the image sensor.

9. The optical system according to any one of claims 1 to 3, wherein, The first lens has a meniscus shape convex toward the object side on the optical axis, wherein, the second lens has a meniscus shape convex toward the sensor side on the optical axis.

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

11. The optical system according to claim 10, wherein, The fifth lens has a meniscus shape convex toward the sensor side on the optical axis.

12. The optical system according to claim 11, wherein, The first lens has an aspherical object side surface and an aspherical sensor side surface, wherein, the second lens to the fifth lens have spherical object side surfaces and spherical sensor side surfaces.

13. The optical system according to any one of claims 1 to 3, wherein, The effective diameters of the third lens to the fifth lens are smaller than the diagonal length of the image sensor.

14. The optical system according to any one of claims 1 to 3, wherein, The refractive indices of the third lens and the fourth lens are higher than the average value of the refractive indices of the first lens to the fifth lens.

15. The optical system according to any one of claims 1 to 3, wherein, The first lens to the fifth lens are made of glass, and the object side surfaces and sensor side surfaces of the first lens to the fifth lens are arranged without critical points.

16. The optical system according to any one of claims 1 to 3, wherein, S7SagD1 is the Sag data at a point spaced a first distance from the center of the object side of the fourth lens, wherein, S8SagD1 is the Sag data at a point spaced a first distance from the center of the sensor side of the fourth lens, wherein, the following formula is satisfied: |S7SagD1| - |S8SagD1| < 0.2 mm.

17. The optical system according to claim 16, wherein, The first distance is the point of 1 / 2 of the average effective radius of the object side surface and sensor side surface of the fourth lens, wherein, the following formula is satisfied: S7SagD1 > 0 and S8SagD1 < 0.

18. The optical system according to any one of claims 1 to 3, wherein, The maximum distance from a straight line perpendicular to the optical axis on the object side surface of the fifth lens to the object side surface of the fifth lens in the direction of the optical axis is Max_Sag51, wherein the maximum distance from a straight line perpendicular to the optical axis on the sensor side surface of the fifth lens to the sensor side surface of the fifth lens in the direction of the optical axis is Max_Sag52, and wherein the following formula is satisfied: |Max_Sag52| < |Max_Sag51|.

19. The optical system according to claim 18, wherein, the following formula is satisfied: Max_Sag51 < 0 and Max_Sag51 < 0.

20. An imaging device module, comprising: the optical system according to any one of claims 1 to 3, wherein the distance from the object side surface of the first lens to the optical axis of the image sensor is TTL, wherein the total number of lenses is nL, wherein the number of aspherical lenses among the first lens to the fifth lens is nASL, wherein half of the diagonal length of the image sensor is ImgH, wherein the following formula is satisfied: 3 < TTL / ImgH < 5 wherein the following formula is satisfied: 0 < nASL / nL < 0.5.

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