Optical system and imaging device module

Abstract

An optical system according to an embodiment of the present invention includes first to seventh lenses arranged along an optical axis, in which the first lens has a negative (-) refractive power, a composite refractive power of the second to seventh lenses is a positive (+) refractive power, a second lens among the first to third lenses has a minimum effective diameter, and a third lens among the first to third lenses has a minimum effective diameter. And effective diameters of the sixth lens and the seventh lens are smaller than an effective diameter of the fifth lens.

Description

Technical Field

[0001] Teachings according to exemplary and non-limiting embodiments of the present invention generally relate to camera modules. Background Art

[0002] ADAS (Advanced Driver Assistance System) is an advanced driver assistance system designed to assist the driver in driving, and includes sensing the situation in front of the vehicle, making a situation judgment based on the sensing result, and controlling the behavior of the vehicle based on the situation judgment. For example, an ADAS sensor device detects the vehicle in front and identifies its lane. Then, when the target lane, target speed, and target in front of the vehicle are determined, the electronic stability control (ESC), engine management system (EMS), electric power steering (MDPS), etc. of the vehicle are controlled. For example, ADAS can be implemented as an automatic parking system, a low-speed city driving assistance system, a blind spot warning system, etc.

[0003] In ADAS, sensor devices for detecting the situation in front of the vehicle may include GPS sensors, laser scanners, forward radars, Lidar, etc., and the most representative device may be a camera device for photographing the front, rear, and sides of the vehicle.

[0004] Such a camera device can be arranged outside or inside the vehicle to detect the surrounding conditions of the vehicle. In addition, the camera device can be arranged inside the vehicle to detect the conditions of the driver and passengers. For example, the camera device can shoot the driver from a position adjacent to the driver, and can detect the driver's health, whether the driver is sleepy, whether the driver is drunk, etc. In addition, the camera device can shoot the passenger from a position adjacent to the passenger, and can detect whether the passenger is sleeping, whether the health is good or other, and can provide information about the passenger to the driver.

[0005] In particular, the most important element for obtaining an image in an image pickup device is an imaging lens that converges the image. Recently, interest in high performance such as high definition and high resolution is increasing, and research is being conducted on an optical system including a plurality of lenses to achieve such high performance. However, there is a problem in that when the image pickup device is exposed to a harsh environment such as high temperature, low temperature, moisture, high humidity, etc., outside or inside a vehicle, the characteristics of the optical system change. In this case, the image pickup device has a problem in that it is difficult to uniformly obtain excellent optical characteristics and aberration characteristics.

[0006] Therefore, a new optical system and imaging device that can solve the above problems are required. Summary of the invention

[0007]

Technical issues

[0008] Embodiments seek to provide optical systems and camera modules having improved optical properties.

[0009] Embodiments seek to provide an optical system and a camera module having excellent optical performance in low to high temperature environments.

[0010] Embodiments seek to provide an optical system and a camera module capable of preventing or minimizing changes in optical properties over a temperature range.

[0011]

Technical Solution

[0012] In one general aspect of the present invention, an optical system may be provided, comprising first to seventh lenses arranged along an optical axis, wherein the first lens has a negative (-) refractive power, the composite refractive power of the second to seventh lenses is a positive (+) refractive power, the second lens among the first to third lenses has a smallest effective diameter, and the effective diameters of the sixth and seventh lenses are smaller than the effective diameter of the fifth lens.

[0013] Preferably, but not necessarily, the second lens, the sixth lens, and the seventh lens may be made of plastic, and at least one lens of the first lens and the third to fifth lenses may be made of glass.

[0014] Preferably, but not necessarily, among the first to seventh lenses, the third lens may have the largest effective diameter.

[0015] Preferably, but not necessarily, the second lens may have a meniscus shape convex toward the sensor.

[0016] Preferably, but not necessarily, a lens having a smallest absolute value of focal length among the first to seventh lenses may be one lens among the third to fifth lenses.

[0017] Preferably, but not necessarily, the absolute values ​​of the focal lengths of the third to fifth lenses may satisfy the following conditional expressions.

[0018] <Conditional expression>

[0019] |F3|≥|F4|≥|F5| (in the above conditional expression, 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).

[0020] In another general aspect of the present invention, an optical system may be provided, comprising first to seventh lenses arranged along an optical axis, wherein the first lens has negative (-) refractive power, wherein the composite refractive power of the second to seventh lenses has positive (+) refractive power, and wherein, among the first to seventh lenses, the absolute value of the focal length of the fifth lens is the smallest, and the absolute value of the focal length of the second lens is the largest.

[0021] Preferably, but not necessarily, the first lens may be made of glass, and the sixth lens and the seventh lens may be made of plastic.

[0022] Preferably, but not necessarily, the optical system may include a cemented lens in which a lens having a positive (+) refractive power and a lens having a negative (-) refractive power are cemented, wherein at least one of a lens disposed on the object side of the cemented lens and disposed closest to the cemented lens and a lens disposed on the sensor side of the cemented lens and disposed closest to the cemented lens may have a convex shape on both sides.

[0023] Preferably, but not necessarily, the absolute value of the curvature radius of the sensor-side surface of the cemented lens may be smaller than the absolute value of the curvature radius of the object-side surface of the cemented lens, and larger than the absolute value of the curvature radius of the remaining lenses.

[0024] Preferably, but not necessarily, the object side of the cemented lens may have a convex shape, and the sensor side of the cemented lens may have a concave shape.

[0025] Preferably, but not necessarily, the cemented lens may include two lenses among the third to fifth lenses that are consecutively arranged back to back.

[0026] In another aspect of the present invention, an optical system may be provided, comprising: first to seventh lenses arranged along an optical axis, wherein, among the first to seventh lenses, the absolute value of the focal length of the second lens is the largest and the absolute value of the focal length of the fifth lens is the smallest, and the ratio of the absolute values ​​of the focal lengths of the second lens and the fifth lens may be greater than 210 times and less than 220 times.

[0027] A ratio of absolute values ​​of focal lengths of the second lens and the third lens may be greater than 100 times and less than 110 times.

[0028] The absolute values ​​of the focal lengths of the third to fifth lenses may satisfy the following conditional expressions.

[0029] <Conditional expression>

[0030] |F3|≥|F4|≥|F5| (in the above conditional expression, 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).

[0031] Preferably, but not necessarily, on the optical axis, the first lens may have the smallest thickness among the first to seventh lenses, and on the optical axis, one lens among the third to fifth lenses may have the largest thickness among the first to seventh lenses.

[0032] Preferably, but not necessarily, the thickness of the second lens on the optical axis may be smaller than the thicknesses of the third lens and the fourth lens.

[0033] Preferably, but not necessarily, among the first to seventh lenses, the absolute value of the curvature radius of the sixth lens on the sensor side may be the largest, and the absolute value of the curvature radius of the fifth lens on the sensor side may be the smallest.

[0034] Preferably, but not necessarily, the third lens may have a convex shape on both sides.

[0035] Preferably, but not necessarily, the first lens, the second lens, the fifth lens, and the seventh lens may have negative (-) refractive power, and the third lens, the fourth lens, and the sixth lens may have positive (+) refractive power.

[0036] In yet another aspect of the present invention, an optical system may be provided, comprising: first to seventh lenses arranged along an optical axis, wherein the first lens has a negative (-) refractive power, wherein the composite refractive power of the second to seventh lenses has a positive (+) refractive power, wherein the effective diameter of the second lens is the smallest among the first to third lenses, and wherein a thickness of the first lens along the optical axis is greater than a thickness of the second lens.

[0037] Preferably, but not necessarily, the first lens, the second lens, the sixth lens, and the seventh lens are made of plastic, and at least one lens of the third to fifth lenses may be made of glass.

[0038] Preferably, but not necessarily, effective diameters of the sixth lens and the seventh lens may be smaller than that of the fifth lens, and the effective diameter of the third lens may be the largest among the first to seventh lenses.

[0039] Preferably, but not necessarily, the second lens may have a convex meniscus shape facing the sensor.

[0040] Preferably, but not necessarily, the lens having the smallest absolute value of focal length among the first to seventh lenses may be one lens among the third to fifth lenses.

[0041] Preferably, but not necessarily, the absolute values ​​of the focal lengths of the third to fifth lenses may satisfy the following conditional expressions.

[0042] <Conditional expression>

[0043] |F3|≥|F4|≥|F5| (in the above conditional expression, 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).

[0044] In another aspect of the present invention, an optical system may be provided, comprising: first to seventh lenses arranged along an optical axis, wherein the first lens has a negative (-) refractive power, the composite refractive power of the second to seventh lenses has a positive (+) refractive power, and the thickness of the first lens along the optical axis may be greater than the distance between the first lens and the second lens.

[0045] Preferably, but not necessarily, among the first to seventh lenses, the absolute value of the focal length of the fifth lens may be the smallest, and the absolute value of the focal length of the second lens may be the largest.

[0046] Preferably, but not necessarily, the first lens, the sixth lens and the seventh lens may be made of plastic.

[0047] Preferably, but not necessarily, the optical system may include a cemented lens in which a lens having a positive (+) refractive power and a lens having a negative (-) refractive power are cemented, and at least one of a lens disposed closest to the cemented lens on the object side of the cemented lens and a lens disposed closest to the cemented lens on the sensor side of the cemented lens may have a convex shape on both sides.

[0048] Preferably, but not necessarily, the absolute value of the radius of curvature on the sensor side of the cemented lens may be smaller than the absolute value of the radius of curvature on the object side of the cemented lens.

[0049] Preferably, but not necessarily, the rear surface of the object side of the cemented lens may have a convex shape, and the rear surface of the sensor side of the cemented lens may have a concave shape.

[0050] In yet another aspect of the present invention, an optical system may be provided, comprising: first to seventh lenses arranged along an optical axis, wherein, among the first to seventh lenses, the absolute value of the focal length of the second lens is the largest and the absolute value of the focal length of the fifth lens is the smallest, and the ratio of the absolute values ​​of the focal lengths of the second lens and the fifth lens may be greater than 10 times and less than 15 times.

[0051] Preferably, but not necessarily, a ratio of absolute values ​​of focal lengths of the second lens and the third lens may be greater than 5 times and less than 10 times.

[0052] Preferably, but not necessarily, the absolute values ​​of the focal lengths of the third to fifth lenses may satisfy the following conditional expressions.

[0053] <Conditional expression>

[0054] |F3|≥|F4|≥|F5|

[0055] (In the above conditional expressions, 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).

[0056] Preferably, but not necessarily, on the optical axis, the fifth lens may have the smallest thickness among the first to seventh lenses, and on the optical axis, the fourth lens may have the largest thickness among the first to seventh lenses.

[0057] Preferably, but not necessarily, the thickness of the second lens on the optical axis may be smaller than the thicknesses of the third lens and the fourth lens.

[0058] Preferably, but not necessarily, the fifth lens may have a largest absolute value of a curvature radius on the object side of the fifth lens and a smallest absolute value of a curvature radius on the sensor side of the fifth lens among the first to seventh lenses.

[0059] Preferably, but not necessarily, the third lens may have a convex shape on both sides.

[0060] Preferably, but not necessarily, the first lens, the fifth lens, and the seventh lens may have negative (-) refractive power, and the second lens, the third lens, the fourth lens, and the sixth lens may have positive (+) refractive power.

[0061]

Beneficial Effects

[0062] The optical system and the camera module according to the exemplary embodiment of the present invention may have improved optical properties. Specifically, in the optical system according to the embodiment, the plurality of lenses may have set thickness, refractive power, and spacing from adjacent lenses. Therefore, the optical system and the camera module according to the embodiment may have improved MTF characteristics, aberration control characteristics, resolution characteristics, etc. within a set field of view, and may have good optical performance at the periphery of the field of view.

[0063] In addition, the optical system and the camera module according to the embodiment can have good optical performance in a temperature range from low to high (-40°C to 105°C). Specifically, the multiple lenses included in the optical system can have set materials, refractive powers and refractive indices. Therefore, if the refractive index of each lens changes with temperature, and the focal length of each lens changes accordingly, the plastic lens and the glass lens can compensate each other. In other words, the optical system can effectively perform the distribution of refractive power in a temperature range from low temperature to high temperature, and can prevent or minimize the change in optical properties in a temperature range from low temperature to high temperature. Therefore, the optical system and the camera module according to the embodiment can maintain improved optical properties over a wide temperature range.

[0064] In addition, the optical system and the camera module according to the embodiment can meet the set viewing angle and achieve excellent optical properties by mixing plastic lenses and glass lenses. Therefore, the optical system can provide a thinner automotive camera module. Therefore, the optical system and the camera module can be provided in various applications and devices, and can have excellent optical properties even in a harsh temperature environment, such as when inside a vehicle or exposed to the outside of a vehicle at high temperatures in summer. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 is a side cross-sectional view of an optical system and an image pickup device module thereof according to a first exemplary embodiment.

[0066] Figure 2 It shows that according to Figure 1 A side cross-sectional view showing the relationship between the nth lens and the n-1th lens.

[0067] Figure 3 It is shown Figure 1 A table of lens characteristics of an optical system.

[0068] Figure 4 It is shown Figure 1 Table of aspheric coefficients of lenses in the optical system.

[0069] Figure 5 It is shown Figure 1 A table of the thickness of each lens of an optical system and the spacing between adjacent lenses.

[0070] Figure 6 It is shown Figure 1 A table of Sag values ​​of lens surfaces of the third lens to the sixth lens of the optical system.

[0071] Figure 7 It is shown based on Figure 1A table of chief ray angle (CRA) data at room temperature, low temperature, and high temperature for the position of the image sensor in the optical system.

[0072] Figure 8 It is shown Figure 1 A graph of the diffraction MTF (Modulation Transfer Function) data of an optical system at room temperature.

[0073] Fig. 9 It is shown Figure 1 A graph of the diffraction MTF data of an optical system at low temperatures.

[0074] Fig.10 It is shown Figure 1 A graph of the diffraction MTF data of an optical system at high temperature.

[0075] Fig.11 It is shown Figure 1 A graph of data of aberration characteristics of an optical system at room temperature.

[0076] Fig.12 It is shown Figure 1 A graph showing the aberration characteristics of an optical system at low temperatures.

[0077] Fig.13 It is shown Figure 1 A graph showing data on aberration characteristics of an optical system at high temperatures.

[0078] Fig.14 is a graph showing relative illuminance based on the height of the image sensor according to the first exemplary embodiment.

[0079] Fig.15 is a side cross-sectional view of an optical system and an image pickup device module thereof according to a second embodiment.

[0080] Fig.16 It shows that according to Fig.15 A side cross-sectional view showing the relationship between the nth lens and the n-1th lens.

[0081] Fig.17 It is shown Fig.15 A table of lens characteristics of an optical system.

[0082] Fig.18 It is shown Fig.15 Table of aspheric coefficients of lenses in the optical system.

[0083] Fig.19 It is shown Fig.15 A table of the thickness of each lens of an optical system and the spacing between adjacent lenses.

[0084] Fig. 20 It is shown Fig.15 A table of Sag values ​​of lens surfaces of the third lens to the sixth lens of the optical system.

[0085] Fig.21 It is shown based on Fig.15 A table of chief ray angle (CRA) data at room temperature, low temperature, and high temperature for the position of an image sensor in an optical system.

[0086] Fig. 22 It is shown Fig.15 A graph of the diffraction MTF (Modulation Transfer Function) data of an optical system at room temperature.

[0087] Fig.23 It is shown Fig.15 A graph of the diffraction MTF data of an optical system at low temperatures.

[0088] Fig.24 It is shown Fig.15 A graph of the diffraction MTF data of an optical system at high temperature.

[0089] Fig.25 It is shown Fig.15 A graph of data of aberration characteristics of an optical system at room temperature.

[0090] Fig.26 It is shown Fig.15 A graph showing the aberration characteristics of an optical system at low temperatures.

[0091] Fig. 27 It is shown Fig.15 A graph showing data on aberration characteristics of an optical system at high temperatures.

[0092] Fig.28 is a graph showing relative illuminance based on the height of the image sensor according to the second exemplary embodiment.

[0093] Fig.29 is an example of a vehicle having an optical system according to an exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0094] Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0095] However, the present invention is not limited to the given exemplary embodiments described, but may be implemented in various different forms, and one or more of the components of the exemplary embodiments may be optionally combined or replaced between the embodiments within the scope of the present invention.

[0096] In addition, unless explicitly specifically defined and described, the terms (including technical terms and scientific terms) used in the embodiments of the present invention should be interpreted according to the meaning that would be understood by a person of ordinary skill in the art to which the present invention belongs, and commonly used terms (e.g., terms defined in dictionaries) should be interpreted according to their contextual meanings in the relevant art.

[0097] Furthermore, the terms used in the embodiments of the present invention are intended to describe the embodiments but are not intended to limit the present invention.

[0098] In this specification, unless the context otherwise requires, the singular may also include the plural, and a reference to "at least one (or more) of A and (or) B and C" may include one or more of any combination of A, B and C that can be combined.

[0099] In addition, the terms first, second, A, B, (a), (b), etc. may be used to describe components of embodiments of the present invention. Such terms are intended only to distinguish one component from another, and are not intended to limit the nature or order or sequence of such components by such terms.

[0100] In addition, when a component is described as being “connected,” “coupled” or “attached” to another component, it may include the case where the component is directly “connected,” “coupled” or “attached” to another component, as well as the case where the component is “connected,” “coupled” or “attached” to another component between the component and the other component.

[0101] Furthermore, when described as being formed or disposed “above” or “below” each component, “above” or “below” includes not only a case where two components are in direct contact with each other, but also a case where one or more other components are formed or disposed between the two components. Furthermore, when expressed as “above” or “below”, it can include the meaning of upward as well as downward relative to a single component.

[0102] In the description of the present invention, "object side" may mean the surface of the lens facing the object side relative to the optical axis (OA), and "sensor side" may mean the surface of the lens facing the imaging surface (image sensor) relative to the optical axis. "Object side surface" may be "object side", and "sensor side surface" may be "image side surface". The convex surface of the lens may mean a convex shape in the optical axis or paraxial region, and the concave surface of the lens may mean a concave shape in the optical axis or paraxial region. The radius of curvature, the center thickness, and the optical axis spacing between lenses listed in the lens data table may refer to the value along the optical axis (in mm). The vertical direction may mean the direction perpendicular to the optical axis, and the distal end of the lens or lens surface may mean the distal end of the effective area of ​​the lens through which the incident light passes. Depending on the measurement method, etc., there may be a measurement error of up to ±0.4 mm in the size of the effective diameter of the lens surface. The term "paraxial region" refers to a very narrow area near the optical axis so that the distance that the light falls from the optical axis (OA) is almost zero. In the following, the meaning of the optical axis may include a very narrow area near the center or optical axis of each lens.

[0103] like Figure 1 As shown, the optical system (1000) according to the first exemplary embodiment of the present invention may include five or more lenses. The optical system (1000) and its camera module may be installed inside or outside a vehicle for driver monitoring or for sensing external objects or lanes. The lens may be made of glass or plastic, wherein glass has a smaller linear expansion coefficient than plastic. Therefore, a glass lens is used to suppress changes in the focal imaging position due to temperature changes. However, compared with plastic lenses, glass lenses are expensive, so it is difficult to meet the demand for low cost. Therefore, the lens in the optical system (1000) needs to be composed of a mixture of glass lenses and plastic lenses. By adopting such a plastic lens, the optical system (1000) can provide light weight and low cost due to the reduced thickness of the plastic lens, and the plastic lens can provide good correction for various aberrations such as spherical aberration and chromatic aberration. The plastic lens can also provide an aspherical lens, which can minimize peripheral distortion.

[0104] The optical system (1000) may include n lenses, wherein the n-th lens may be the last lens adjacent to the image sensor (300), and the n-1-th lens may be the lens closest to the last lens. n may be an integer greater than or equal to 5, for example, 5 to 8. The ratio of lenses made of plastic to lenses made of glass in the n lenses may be in the range of 2:3 to 2:6, or in the range of 3:4 to 3:5.

[0105] The optical system (1000) may include a plurality of lens groups (LG1, LG2). More specifically, each of the plurality of lens groups (LG1, LG2) may include at least one lens. For example, the optical system (1000) may include a first lens group (LG1) and a second lens group (LG2) sequentially arranged along an optical axis (OA) from an object side toward an image sensor (300).

[0106] The number of lenses in each lens group of the first lens group (LG1) and the second lens group (LG2) may be different. The number of lenses in the second lens group (LG2) may be greater than the number of lenses in the first lens group (LG1), for example, more than four times the number of lenses in the first lens group (LG1) or more than five times the number of lenses in the first lens group (LG1). The first lens group (LG1) may include at least one lens. The first lens group (LG1) may have three or fewer lenses. Preferably, the first lens group (LG1) may be a single lens. The second lens group (LG2) may include two or more lenses. The second lens group (LG2) may include four to seven (pieces) of lenses. Preferably, the second lens group (LG2) may include six lenses.

[0107] The first lens group (LG1) may include at least one lens made of glass. The first lens group (LG1) may provide a lens closest to the object side as a lens made of glass. Such a glass material may be less likely to expand and contract due to changes in external temperature and may have a surface that is less likely to be scratched, thereby preventing surface damage.

[0108] The lens material of the second lens group (LG2) may be a mixture of at least one glass lens and at least one plastic lens. In the second lens group (LG2), at least one plastic lens may be arranged closer to the sensor than the glass lens. The second lens group (LG2) may include more than two glass lenses, for example two to four glass lenses. The second lens group (LG2) may include, for example, two to six lenses. As another example, the second lens group (LG2) may have at least one lens made of plastic. The second lens group (LG2) may include two or more plastic lenses, for example two to four plastic lenses.

[0109] At least one lens closest to the object in the optical system (1000) can be made of glass material. Three or more lenses closest to the object, for example three to five lenses, can be made of glass material. Since the rate of change of contraction and expansion of glass lenses with temperature changes is smaller than that of plastic lenses, glass lenses can be placed in the outer adjacent area of ​​the lens barrel.

[0110] In the optical system (1000), at least one lens closest to the image sensor (300) may be made of plastic. For example, at least two lenses closest to the image sensor (300) may be made of plastic, and preferably, at least two lenses adjacent to the image sensor (300) may be made of plastic. In other words, the nth lens and the (n-1)th lens in the optical system (1000) are set as plastic lenses, so that various aberrations can be corrected for light incident on the image sensor (300).

[0111] In the optical system (1000), plastic lenses may be arranged continuously in a row, and glass lenses may be arranged continuously in a row (back to back). In the optical system (1000), lenses made of plastic may be disposed between lenses made of glass. In the optical system (1000), lenses made of glass may be disposed between lenses made of plastic.

[0112] Each lens (101 to 107) may have an object side surface and a sensor side surface. In the optical system, the number of lenses having aspherical sensor side surfaces and aspherical object side surfaces may be greater than the number of plastic lenses. The optical system may have a plurality of lenses having spherical sensor side surfaces and spherical object side surfaces, the number of these lenses being less than the number of lenses having aspherical surfaces on both sides. By making the optical system (1000) have more aspherical lenses than spherical lenses, various aberrations can be compensated.

[0113] Among the lenses of the optical system (1000), the lens with the maximum refractive index may be located in the first lens group (LG1) or adjacent to the object. The maximum refractive index may be 1.8 or greater. The dispersion of light incident on the lens with the maximum refractive index may increase, and the center thickness may be thinner than the edge thickness. In addition, since the lens with the maximum refractive index is disposed on the object side, the curvature radius of the second lens and subsequent lenses may be easily changed and the center thickness may be increased.

[0114] In the optical system (1000), a lens having a maximum effective diameter may be disposed at the center of the object side and the sensor side. As the lens moves from the object side to the sensor side, the effective diameter of the lens may first increase and then decrease. As the lens moves from the object side to the sensor side, the effective diameter of the lens may become smaller, then become larger, and then become smaller again. Because light incident on the optical system (1000) moves away from the optical axis and then converges back to the optical axis, this allows the optical system (1000) to form a stable optical path.

[0115] The effective diameter may be the diameter of the effective area of ​​light incident on each lens. The effective diameter is the length in the direction (X, Y) orthogonal to the optical axis, and is the average of the effective diameters of the object side surface and the sensor side surface of each lens. The "diameter of the lens face (surface)" may mean the "effective diameter of the lens". The "diameter of the lens" may be the diameter of the entire lens, which includes the flange portion of the lens in addition to the effective area of ​​the lens. Although Figure 1 and Figure 2 The flange of the lens is not shown in the figure, but the flange can be a part protruding from the side of the lens perpendicular to the optical axis, which is used to couple the lens to the lens barrel. The flange may not receive effective light. Additional spacers can be placed between the flanges of different lenses to allow the lens to be coupled to the lens barrel.

[0116] Each of the lenses (101 to 107) may include an effective area and an ineffective area. The effective area may be an area through which light incident on each lens in the lens passes, i.e., the effective area may be defined as an effective area or effective diameter through which incident light is refracted to achieve optical properties. The ineffective area may be arranged around the periphery of the effective area. The ineffective area may be an area where no effective light is incident on a plurality of lenses, i.e., the ineffective area may be an area that is unrelated to optical properties. In addition, the distal end of the ineffective area may be an area to which a lens barrel or the like that houses the lens is fixed.

[0117] In the optical system (1000), the total top length (TTL) can be more than two times, for example more than four times but less than twelve times, of Imgh. The total track length (TTL) is the distance from the center of the object side of the first lens on the optical axis (OA) to the image (top) surface of the image sensor (300). Imgh is the distance on the optical axis (OA) to the diagonal end of the image sensor (300), or 1 / 2 of the maximum diagonal length. In the optical system (1000), an effective focal length (EFL) of at least 10 mm and a field of view (FOV) of less than 45 degrees can be provided, which can be provided by standard optical devices in an automotive camera module. For example, the optical system and camera module according to the exemplary embodiment can be applied to a camera of an advanced driver assistance system (ADAS) inside or outside a vehicle.

[0118] The optical system (1000) may have a TTL / Imgh of at least 5 and at least 7.5, such as at least 6 and at least 7. The optical system (1000) may provide an automotive lens optical system by setting the TTL / Imgh to a value of at least 5 times and not more than 7.5 times.

[0119] The total number of lenses in the first lens group (LG1) and the second lens group (LG2) is 8 or less. Therefore, the optical system (1000) can provide an image without exaggeration or distortion to resolve the image.

[0120] The effective diameter of at least one plastic lens in the optical system (1000) may be smaller than the length of the image sensor (300). The effective diameter is the diameter or length of the effective area through which light is incident. The length of the image sensor (300) is the maximum length of a diagonal line in a direction orthogonal to the optical axis (OA). In the optical system (1000), the number of lenses having an effective diameter greater than the length of the image sensor (300) may be greater than 50% or greater than 60%, and the number of lenses having an effective diameter less than the length of the image sensor (300) may be less than 50% or less than 40%.

[0121] The optical system (1000) may include at least one cemented lens (145) therein. The cemented lens (145) is a cementation of at least two lenses having different refractive powers, and a gap between the two lenses may be less than 0.01 mm. The cemented lens (145) may be a lens in which two lenses having different focal lengths are cemented. The bonding of the two lenses may be bonded with an adhesive. The effective diameter of at least one lens or all lenses of the lenses arranged on the object side relative to the cemented lens (145) may be greater than the length of the image sensor (300). The effective diameter of at least one lens arranged on the sensor side relative to the cemented lens (145) may be less than the length of the image sensor (300). In addition, the object side lens (103) of the cemented lens (145) may be greater than the length of the image sensor (300), and the sensor side lens (104) may be greater than the length of the image sensor (300).

[0122] The lens between the cemented lens (145) and the first lens (101) can be made of glass or plastic. The lens arranged between the cemented lens (145) and the image sensor (300) can be made of plastic. The lens between the cemented lens (145) and the first lens (101) can be spherical on both sides or aspherical on both sides. The lens arranged between the cemented lens (145) and the image sensor (300) can be an aspherical lens on both sides. The two sides are the object side and the sensor side. Therefore, by arranging an aspherical lens between the cemented lens (145) and the image sensor (300), the optical performance can be improved by correcting the curvature aberration and the chromatic aberration.

[0123] On the optical axis (OA), the first lens group (LG1) and the second lens group (LG2) may have a set spacing. The optical axis spacing between the first lens group (LG1) and the second lens group (LG2) in the optical axis (OA) direction may be an optical axis spacing between a sensor side surface of a lens closest to the sensor side among the lenses in the first lens group (LG1) and an object side surface of a lens closest to the object side among the lenses in the second lens group (LG2). The optical axis spacing between the first lens group (LG1) and the second lens group (LG2) may be less than or equal to one times the optical axis distance of the first lens group (LG1), for example, in a range of 0.1 times to 1 times the optical axis distance of the first lens group (LG1).

[0124] The optical axis distance between the first lens group (LG1) and the second lens group (LG2) may be less than or equal to 0.2 times the optical axis distance of the second lens group (LG2), for example, in the range of 0.01 times to 0.2 times. The optical axis distance of the second lens group (LG2) is the optical axis distance between the object side surface of the lens closest to the object side in the second lens group (LG2) and the sensor side surface of the lens closest to the image sensor (300).

[0125] Here, two of the lens (surface) surfaces of the first lens group (LG1) and the second lens group (LG2) that face each other, for example, the sensor side surface of the object side lens may be concave and the object side surface of the sensor side lens may be concave, that is, the sensor side surface closest to the sensor side in the first lens group (LG1) may be concave and the object side surface closest to the object side in the second lens group (LG2) may be concave. The first lens group (LG1) may diffuse light incident through the object side, and the second lens group (LG2) may refract light diffused by the first lens group (LG1) to an area of ​​the image sensor (300).

[0126] The first lens group (LG1) may have a negative (-) refractive power, and the second lens group (LG2) may have a positive (+) refractive power. Among the lenses of the first lens group (LG1), the lens closest to the object side may have a negative (-) refractive power, and among the lenses of the second lens group (LG2), the lens closest to the sensor side may have a negative (-) refractive power. When the focal length is expressed as an absolute value, the focal length of the first lens group (LG1) may be greater than the focal length of the second lens group (LG2), for example, 2 times greater, for example, in the range of 2 times to 10 times. The effective focal length (EFL) of the optical system (1000) may be less than the absolute value of the focal length of the first lens group (LG1). The effective focal length (EFL) of the optical system (1000) may be less than the absolute value of the focal length of the first lens group (LG1) and greater than the absolute value of the focal length of the second lens group (LG2).

[0127] In the optical system (1000), the number of lenses having negative (-) refractive power may be equal to or greater than the number of lenses having positive (+) refractive power. The number of lenses having negative (-) refractive power may account for 50% or more of the total number of lenses. The average refractive index of lenses having negative (-) refractive power may be greater than the average refractive index of lenses having positive (+) refractive power. Therefore, the variation range of lenses having positive (+) refractive power may be greater than the variation range of lenses having negative (-) refractive power.

[0128] The lens portion (100) may include a mixture of glass lenses and plastic lenses. The number of plastic lenses may be 60% or less of the total number of lenses, and may be in the range of 30% to 60%, or in the range of 30% to 50%. Therefore, when more plastic lenses are provided in the camera module, the weight of the camera module may be reduced, and the plastic material may be easily polished, processed, and withstand external impacts, and the price is competitive and the material is easy to fix. In addition, various aberrations may be corrected by the plastic lens, which may prevent the optical performance from being reduced.

[0129] The first exemplary embodiment of the present invention can also incorporate a plastic lens into the optical system (1000), which can reduce the weight of the camera module, provide lower manufacturing costs, suppress the degradation of optical properties with temperature changes, allow different types of plastic lenses to replace glass lenses, and facilitate polishing and processing of lens surfaces such as aspheric or free-form surfaces.

[0130] The lens portion (100) may include a lens of a first material and a lens of a second material arranged along an optical axis (OA). The first material may be glass, and the second material may be plastic. The lens of the first material may be arranged between the lenses of the second material. The lens of the second material may be arranged between the lenses of the first material.

[0131] The lens portion (100) may include a first material lens having an aspherical surface along an optical axis (OA), a first material lens having a spherical surface, and a second material lens having an aspherical surface. The first material may be glass, and the second material may be plastic. The first material lens having a spherical surface may be arranged between the second material lens having an aspherical surface. The second material lens may be arranged between the first material lens having an aspherical surface and the first material lens having a spherical surface.

[0132] Within the lens unit (100), the effective diameter of the lens closest to the object side can be larger than the effective diameter of the lens closest to the image sensor (300). Thus, the brightness of the optical system can be controlled. The effective diameter can be the average effective diameter of the object side surface and the sensor side surface of each lens. By controlling the size of the effective diameter of each lens, the optical system (1000) can control the incident light to compensate for the degradation of optical properties due to changes in resolution and temperature, improve the chromatic aberration control characteristics, and improve the vignetting characteristics of the optical system (1000).

[0133] The lens unit (100) may include a first lens (101), a second lens (102), a third lens (103), a fourth lens (104), a fifth lens (105), a sixth lens (106), and a seventh lens (107) aligned along the optical axis from the object side toward the sensor side.

[0134] Within the lens unit (100), when the focal length is taken as an absolute value, the focal length of the lens closest to the object can be larger than the focal length of the plastic lens. Here, the plastic lens can be at least one lens provided on the sensor side of the cemented lens, or at least one lens adjacent to the image sensor. The focal length (F1) of the first lens (101) can be the largest in the optical system and can be larger than the focal length (absolute value) of the second lens group (LG2), that is, the condition |FLG2| < F1 can be satisfied.

[0135] In the lens unit (100), there can be three or more lenses, such as four or more lenses, whose average effective diameter is larger than the average effective diameter of the plastic lens. If the average effective diameter of the plastic lens is PLca_Aver and the average effective diameter of the glass lens is GLca_Aver, the condition PLca_Aver < GLca_Aver can be satisfied. In addition, the condition 1 < GLca_Aver / PLca_Aver < 1.5 can be satisfied. In addition, the relationship between the length of the image sensor (300) and the average effective diameter (PLca_Aver) of the plastic lens can satisfy the condition 1 ≤ PLca_Aver / (Imgh*2) < 1.5. In addition, the relationship between the average effective diameter of the glass material and the length of the image sensor (300) can satisfy the condition 1.1 < GLca_Aver / (Imgh*2) < 1.5. The difference between the maximum length of the image sensor (300) and the effective diameter of the plastic lens can be set to be small. Thus, by arranging the plastic lens with a small effective diameter adjacent to the image sensor (300), the plastic lens can distribute the color from the center to the periphery of the image sensor (300).

[0136] The glass material may have an average effective diameter of at least 10 mm, for example, in the range of 10 mm to 15 mm. The plastic material may have an average effective diameter of at least 8 mm, for example, in the range of 8 mm to 12 mm. The lens with the smallest effective diameter may be made of plastic, and the lens with the largest effective diameter may be made of glass. In the lens portion (100), the smallest effective diameter may be in the range of 7 mm to 10 mm, and the largest effective diameter may be in the range of 11 mm to 15 mm. The lens made of plastic may be designed to have an effective diameter smaller than that of a lens made of glass, so that the lens made of plastic may be positioned away from the lens barrel, thereby minimizing the change in optical performance due to temperature changes. In addition, the optical system (1000) may control incident light to improve resolution, improve chromatic aberration control characteristics, and improve the vignetting characteristics of the optical system (1000).

[0137] The optical system (1000) or the camera module may include an image sensor (300). The image sensor (300) may detect light and convert it into an electrical signal. The image sensor (300) may detect light that sequentially passes through the lens portion (100). The image sensor (300) may include an element capable of detecting incident light, such as a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS).

[0138] Here, the length of the image sensor (300) is the maximum length in the diagonal direction orthogonal to the optical axis (OA), and may be smaller than the effective diameter of the lens closest to the object in the first lens group (LG1), and larger than the effective diameter of the lens closest to the sensor in the second lens group (LG2). Here, the number of lenses having an effective diameter larger than the length of the image sensor (300) may be from 4 to 6, and the number of lenses having an effective diameter smaller than the length of the image sensor (300) may be from 1 to 3.

[0139] The optical system (1000) or the camera 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 filter (500) may be disposed between the nth lens and the image sensor (300).

[0140] The cover glass (400) may be disposed between the filter (500) and the image sensor (300), and may protect the top of the image sensor (192) and prevent the reliability of the image sensor (192) from being reduced. The cover glass (400) may be removable. The cover glass (400) may be a protective glass.

[0141] The filter (500) may include an infrared filter or an infrared cut filter (IR cut). The filter (500) may allow light of a set wavelength band to pass through and filter out light of a different wavelength band. If the filter (500) includes an infrared filter, it may block radiant heat emitted from external light from reaching the image sensor (300). In addition, the filter (500) may transmit visible light and reflect infrared light.

[0142] The optical system (1000) according to an exemplary embodiment may include an aperture (stop). The aperture may adjust the amount of light incident on the optical system (1000). For a lens disposed between an object and the aperture, the effective diameter of the lens surface tends to increase from the object side toward the aperture. For a lens surface disposed between the aperture and the sensor, the effective diameter of the lens surface (surface) tends to decrease as it moves from the aperture to the sensor side. The meaning that the effective diameter of the lens surface tends to increase or decrease does not mean that the effective diameter of the lens surface only increases or decreases. For example, the effective diameter of the lens surface may first increase and then decrease from the aperture to the sensor side.

[0143] The aperture may be set at a predetermined position. For example, the aperture may be set at the periphery of the object side surface or the sensor side surface of the lens closest to the object side among the lenses of the second lens group (LG2). Alternatively, the aperture may be set around the periphery of the object side surface or the sensor side surface of the object side lens of the first lens group (LG1). Alternatively, at least one lens selected from a plurality of lenses may be used as the aperture. More specifically, the object side surface or the sensor side surface of at least one lens selected from a plurality of lenses of the optical system (1000) may be used as the aperture to adjust the amount of light.

[0144] In the optical system (1000) of the first exemplary embodiment, the sum of the refractive indices of the lenses of the lens portion (100) may be at least 8, for example, in the range of 8 to 15, and the average refractive index may be in the range of 1.58 to 1.7. The sum of the Abbe numbers of each lens in the lens may be greater than or equal to 300, for example, in the range of 310 to 350, and the average value of the Abbe numbers may be less than or equal to 50, for example, in the range of 35 to 47. The sum of the center thicknesses of all lenses may be in the range of 18 mm or more, for example, in the range of 20 mm to 25 mm, and the average value of the center thicknesses may be in the range of 2.8 mm to 3.5 mm. The sum of the center spacings between the lenses on the optical axis (OA) may be at least 6 mm, for example, in the range of 6.8 mm to 8 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 (S1 to S14) of the lens portion (100) may be provided in the range of 8 mm or more, for example, in the range of 8 mm to 15 mm.

[0145] In the optical system according to the first exemplary embodiment of the present invention, the field of view (diagonal) may be 50 degrees or less, for example, in the range of 20 to 50 degrees. The F number of the optical system or camera module may be 2.4 or less, for example, in the range of 1.4 to 2.4, or in the range of 1.5 to 1.8. In the optical system according to the first embodiment of the present invention, the maximum field of view (diagonal) may be 50 degrees or less, for example, in the range of 20 to 50 degrees. In the automotive optical system, the horizontal field of view (FOV_H) in the Y-axis direction may be greater than 20 degrees and less than 40 degrees, for example, in the range of 25 to 35 degrees. In addition, the vertical field of view may be set at an angle smaller than the horizontal field of view, and may be less than 20 degrees, for example, in the range of 10 to 20 degrees. In this case, the sensor length in the horizontal direction (Y) may be 8.064 mm ± 0.5 mm, and the sensor height in the vertical direction (X) may be 4.54 mm ± 0.5 mm. The horizontal field of view (FOV_H) is a viewing angle based on the horizontal length of the sensor. Therefore, changes in the focal imaging position due to temperature changes can be suppressed, and a vehicle imaging device that corrects various aberrations well can be provided.

[0146] Since the first exemplary embodiment is an optical system applied to a vehicle camera device, the first lens (101) can be set to a glass material, although the first lens (101) can be designed to use a combination of a plastic lens and a glass lens. Compared with plastic materials, glass materials have the advantages of being scratch-resistant and insensitive to external temperature. The first lens (101) can be a glass molded lens having an aspherical surface and made of glass. The glass molded lens can be produced by heating and compressing an optical glass ingot in a mold to form an aspherical shape.

[0147] A glass lens may be used as the first lens (101) to more effectively prevent scratches from foreign objects placed inside the vehicle, and the object side surface of the first lens (101) may have a slightly curved shape so that the first lens does not contact the external structure. This minimizes the occurrence of scratches due to contact with the external structure. The field of view may be greater than 20 degrees and less than 40 degrees, for example in the range of 25 degrees to 35 degrees, for driver monitoring during vehicle operation, front and rear views of the vehicle or lane detection, and detection of unexpected objects around the vehicle. This horizontal field of view may be a preset angle for an advanced driver assistance system (ADAD).

[0148] The optical system (1000) according to the first exemplary embodiment may further include a reflective member for re-changing the light path. The reflective member may be implemented as a prism that reflects incident light from the first lens group (LG1) in the direction of the lens. Hereinafter, the optical system according to the embodiment will be described in detail.

[0149] An optical system according to a first exemplary embodiment of the present invention will now be described.

[0150] Figure 1 is a side sectional view of an optical system and an image pickup device module thereof according to a first exemplary embodiment, Figure 2 It shows that according to Figure 1 A side cross-sectional view showing the relationship between the n-th lens and the n-1-th lens, Figure 3 It is shown Figure 1 Table of lens characteristics of optical systems, Figure 4 It is shown Figure 1 Table of aspheric coefficients of lenses in optical systems, Figure 5 It is shown Figure 1 A table showing the thickness of each lens of the optical system and the spacing between adjacent lenses. Figure 6 It is shown Figure 1 Table of Sag values ​​of lens surfaces of the third lens to the sixth lens of the optical system, Figure 7 It is shown based on Figure 1 A table of chief ray angle (CRA) data at room temperature, low temperature, and high temperature for the position of the image sensor in the optical system, Figure 8 It is shown Figure 1 The graph of the diffraction MTF (Modulation Transfer Function) data of the optical system at room temperature is shown in Figure 2. Fig. 9 It is shown Figure 1 The graph of the diffraction MTF data of the optical system at low temperature, Fig.10 It is shown Figure 1 The graph of the diffraction MTF data of the optical system at high temperature, Fig.11 It is shown Figure 1 A graph showing the aberration characteristics of an optical system at room temperature. Fig.12 It is shown Figure 1 A graph showing the aberration characteristics of an optical system at low temperatures. Fig.13 It is shown Figure 1 A graph of data on aberration characteristics of an optical system at high temperatures, and Fig.14 is a graph showing relative illuminance based on the height of the image sensor according to the first exemplary embodiment.

[0151] Reference Figures 1 to 4The optical system (1000) may include a lens unit (100), and the lens unit (100) may include a first lens (101) to a seventh lens (107). The first lens to the seventh lens (101 to 107) may be sequentially arranged along an optical axis (OA) of the optical system (1000). Light corresponding to information about an object may be incident on an image sensor (300) after passing through the first lens (101) to the seventh lens (107) and the filter (500).

[0152] The first lens (101) may be a lens closest to the object side in the first lens group (LG1). The seventh lens (107) may be a lens closest to the image sensor (107) in the second lens group (LG2) or the lens unit (100). The first lens (101) may be the first lens group (LG1), and the second to seventh lenses (102, 103, 104, 105, 106, 107) may be the second lens group (LG2). An aperture may be provided on the periphery of the object side surface or the sensor side surface of the first lens (101) or on the periphery of the object side surface or the sensor side surface of the second lens (102). For example, an aperture (stop) may be provided on the periphery of the object side surface of the second lens (102).

[0153] The first lens (101) may be arranged to be closest to the object side. The first lens (101) may be arranged to be farthest from the sensor side. The first lens (101) may have a negative (-) refractive power on the optical axis (OA). The first lens (101) may include a plastic material or a glass material, for example, a glass material. The first lens (101) made of glass can reduce changes in the center position and the radius of curvature due to temperature changes in the surrounding environment, and can protect the incident side surface of the optical system (1000).

[0154] The first surface (S1) on the object side of the first lens (101) may be convex with respect to the optical axis, and the second surface (S2) on the sensor side may be concave. The first lens (101) may have a convex meniscus shape toward the object side. The first lens (101) may be made of glass and may have an aspherical surface. The aspherical coefficients of the first surface (surface) (S1) and the second surface (surface) (S2) may be given by Figure 4 L1S1 and L1S2 are given in FIG. Such a first lens (101) can be manufactured as a lens having an aspherical surface by injection molding a glass material. The first lens (101) can be a glass molded lens having an aspherical surface and made of a glass material. The glass molded lens can be manufactured by placing an optical glass ingot in a mold to be formed into an aspherical shape, and heating and compressing it.

[0155] The effective radius (r11) of the first lens (101) may be greater than the effective radius of the plastic lens. In contrast, at least one of the object side surface and the sensor side surface of the first lens (101) may have a free curved surface, that is, a non-rotationally symmetric curved surface.

[0156] Since the first surface (S1) is convex and the second surface (S2) is concave, the first lens can refract incident light in a direction away from the optical axis (OA) and reduce the gap between the first lens (101) and the second lens (102). In addition, the effective diameter of the sensor side surface of the second lens (102) can be designed to be smaller than the effective diameter of the object side surface by the shape of the lens surface of the first lens (101). The first surface (S1) of the first lens (101) can be set to have no critical point from the optical axis (OA) to the far end, i.e., the edge, of the effective area. The second surface (S2) of the first lens (101) can be set to have no critical point.

[0157] The refractive index n1 of the first lens (101) may satisfy the condition of n1>1.8 or n1>1.82. Since the refractive index n1 of the first lens (101) is the largest in the lens portion (100), the radius of curvature of the first lens (101) and the second lens (102) may be larger, and lens manufacturing may be easy. If the refractive index n1 of the first lens (101) is less than the condition, the lens surface needs to be sharply concave or convex to increase the refractive power of the first lens (101) and the second lens (102), which may not be easy to manufacture the lens and may result in a high lens defect rate and low yield.

[0158] The second lens (102) may be arranged to be the second on the object side. The second lens (102) may be arranged to be the sixth from the sensor side. The second lens (102) may be arranged between the first lens (101) and the third lens (103). The second lens (102) may have a negative (-) refractive power on the optical axis (OA). The second lens (102) may include a plastic or glass material. For example, the second lens (102) may be arranged to be a plastic material.

[0159] The object-side third surface (S3) of the second lens (102) may be concave and the sensor-side fourth surface (S4) may be convex relative to the optical axis (OA). The second lens (102) may have a convex meniscus shape toward the sensor side. The second lens (102) may be made of plastic and may be aspherical. At least one or both of the third surface (S3) and the fourth surface (S4) may be aspherical. The aspherical coefficients of the third surface (S3) and the fourth surface (S4) may be as follows: Figure 4At least one or both of the third surface (S3) and the fourth surface (S4) may be configured to have no critical point from the optical axis (OA) to the far end of the effective area.

[0160] An aperture (stop) may be provided around the periphery of the third surface (S3) on the object side of the second lens (102). The composite focal length of the second lens to the seventh lens (102 to 107) provided on the sensor side of the aperture may have a positive value, which may reduce the TTL within the field of view and achieve miniaturization of the optical system. Therefore, it is possible to prevent the yield by weight of the optical system from being reduced, and to improve production efficiency. In addition, the TTL may be reduced by reducing the horizontal field of view (FOV_H) from 25 degrees to 36 degrees, so as to miniaturize the optical system.

[0161] The third lens (103) may be arranged to be the third from the object side. The third lens (103) may be arranged to be the fifth from the sensor side. The third lens (103) may be arranged between the second lens (102) and the fourth lens (104). The third lens (103) may have a positive (+) refractive power on the optical axis (OA). The third lens (103) may include a plastic or glass material. For example, the third lens (103) may be arranged to be a glass material.

[0162] Relative to the optical axis, the object-side fifth surface (S5) of the third lens (103) may be convex, and the sensor-side sixth surface (S6) may be convex. The third lens (103) may have a convex shape on both sides on the optical axis (OA). The third lens (103) may be made of glass and may be spherical. At least one or both of the fifth surface (S5) and the sixth surface (S6) may be spherical. At least one or both of the fifth surface (S5) and the sixth surface (S6) may be arranged to have no threshold point from the optical axis (OA) to the far end of the effective area.

[0163] Since both sides of the third lens (103) are convexly arranged, the TTL and the number of lenses of the optical system can be minimized, and light can be refracted efficiently. In addition, if the radius of curvature of the fifth surface (S5) of the third lens (103) is L3R1, and the radius of curvature of the sixth surface (S6) is L3R2, the condition of L3R1>|L3R2| can be satisfied. If this condition is satisfied, light can be effectively refracted by the fifth surface (S5) to guide the effective diameter of the fourth lens to the seventh lens (104 to 107) without increasing, and TTL can be reduced. If L3R1<|L3R2|, the third lens (103) may generate a large amount of aberration on the object side surface, and the refraction efficiency of light on the sensor side surface may be reduced, and the effective diameter of the rear lens may increase, and TTL may increase.

[0164] The fourth lens (104) may be arranged to be fourth from the object side. The fourth lens (104) may be arranged to be fourth from the sensor side. The fourth lens (104) may be arranged between the third lens (103) and the fifth lens (105). The fourth lens (104) may have a positive (+) refractive power or a negative (-) refractive power on the optical axis (OA). The fourth lens (104) may have a positive (+) refractive power. The fourth lens (104) may have a positive (+) refractive power different from the refractive power of the fifth lens (105). The fourth lens (104) may include a plastic or glass material. For example, the fourth lens (104) may be arranged to be a glass material. The fourth lens (104) may be arranged to be the same material as that of the fifth lens (105).

[0165] Relative to the optical axis, the object-side seventh surface (S7) of the fourth lens (104) may be convex, and the sensor-side eighth surface (S8) may be convex. The fourth lens (104) may be convex on both sides. The fourth lens (104) may be made of glass and may have a spherical surface. At least one or both of the seventh surface (S7) and the eighth surface (S8) may be spherical. The seventh surface (S7) and the eighth surface (S8) may be arranged to have no threshold from the optical axis (OA) to the far end of the effective area.

[0166] The fifth lens (105) may be arranged to be fifth from the object side. The fifth lens (105) may be arranged to be third from the sensor side. The fifth lens (105) may be arranged between the fourth lens (104) and the sixth lens (106). The fifth lens (105) may have a positive (+) refractive power or a negative (-) refractive power on the optical axis (OA). The fifth lens (105) may have a negative (-) refractive power. The fifth lens (105) may have a negative (-) refractive power different from the refractive power of the fourth lens (104). The fifth lens (105) may include a plastic or glass material. For example, the fifth lens (105) may be arranged to be a glass material. The fifth lens (105) may be arranged to be the same material as that of the fourth lens (104).

[0167] The fifth lens (105) may have a concave ninth object side surface (S9) and a concave tenth sensor side surface (S10) relative to the optical axis (OA). The fifth lens (105) may have a concave shape on both sides on the optical axis (OA). Alternatively, the fifth lens (105) may have a convex shape on both sides. The fifth lens (105) may be made of glass and may have a spherical surface. At least one of the ninth surface (S9) and the tenth surface (S10) may be spherical. For example, both the ninth surface (S9) and the tenth surface (S10) may be spherical. At least one or both of the ninth surface (S9) and the tenth surface (S10) of the fifth lens (105) may be arranged to have no threshold point from the optical axis (OA) to the far end of the effective area.

[0168] The fourth lens (104) and the fifth lens (105) may be cemented. The bonding surface between the fourth lens (104) and the fifth lens (105) may be defined as an eighth surface (S8). The eighth surface (S8) may be the same surface as the ninth surface of the fifth lens (105). The object side surface of the cemented lens (145) may be convex, and the sensor side surface may be concave. The gap between the fourth lens (104) and the fifth lens (105) may be less than 0.01 mm, and may be bonded (glued) with an adhesive. The spacing between the fourth lens (104) and the fifth lens (105) may be less than 0.01 mm from the optical axis (OA) to the far end of the effective area. The fourth lens (104) and the fifth lens (105) may have opposite refractive powers. The composite refractive power of the fourth lens (104) and the fifth lens (105) may have a positive (+) refractive power.

[0169] The value of the radius of curvature of the cemented surface (S8) of the cemented lens (145) may be greater than 30. For example, the value of the radius of curvature of the cemented surface (S8) of the cemented lens (145) may be greater than 50. The cemented surface (S8) of the cemented lens (145) may be formed in a flat shape. Therefore, the bonding (gluing) process of the fourth lens (104) and the fifth lens (105) forming the cemented lens (145) is favorable, and the bonding (gluing) holding force can be improved.

[0170] The product of the refractive power of the third lens (103) on the object side of the cemented lens (145) and the refractive power of the fourth lens (104) on the sensor side can be less than zero. The product of the focal length of the third lens (103) on the object side of the cemented lens (145) and the focal length of the fourth lens (104) on the sensor side can be less than zero. This can improve the aberration characteristics of the optical system. If the two lenses of the cemented lens (145) have the same refractive power, the aberration improvement is limited.

[0171] The combined refractive power of the cemented lens (145) may have a positive (+) refractive power, and with respect to the cemented lens (145), the fourth lens (104) on the object side and the fifth lens (105) on the sensor side may have positive (+) refractive powers. Accordingly, the fourth lens (104), the cemented lens (145), and the fifth lens (105) may refract some of the incident light in the incident light in the optical axis direction and may compensate for chromatic aberration with each other. With respect to the cemented lens (145), the focal length of the fourth lens (104) provided on the object side may be smaller than the focal length of the fifth lens (105) provided on the sensor side. With respect to the cemented lens (145), the refractive power of the fourth lens (104) provided on the object side may be greater than the refractive power of the fifth lens (105) provided on the sensor side.

[0172] The effective diameter of the fourth lens (104) may be greater than the diagonal length of the image sensor (300). The effective diameter of the fourth lens (104) is the average of the effective diameters of the seventh surface (S7) and the eighth surface (S8) and may be greater than the diagonal length of the image sensor (300). The effective diameter of the fifth lens (105) is smaller than the effective diameter of the fourth lens (104) and may be greater than the diagonal length of the image sensor (300).

[0173] When the effective diameter of the seventh surface (S7) of the fourth lens (104) is CA_L4S1 and the effective diameter of the eighth surface (S8) is CA_L4S2, the effective diameters of the seventh surface (S7) and the eighth surface (S8) may satisfy the condition of 1 < CA_L4S1 / CA_L4S2 < 1.5. If the effective diameter of the ninth surface (S9) of the fifth lens (105) is CA_L5S1 and the effective diameter of the tenth surface (S10) is CA_L5S2, the effective diameters of the ninth surface and the tenth surface may satisfy the condition of 1 < CA_L5S1 / CA_L5S2 < 1.5.

[0174] The cemented lens (145) is cemented using glass lenses having different refractive indices and has spherical refracting surfaces, and if an aspherical lens or a plastic lens is employed, the lens provided on the sensor side compared with the cemented lens (145) may compensate for spherical aberration. Further, if the lenses provided on the sensor side of the cemented lens (145) are plastic lenses and have a small effective diameter, these lenses may be arranged to effectively guide light through the plastic lenses to the image sensor (300). The position of the cemented lens (145) may be located between or behind any two consecutive lenses among the third lens to the sixth lens in the lens unit (100) such that chromatic aberration correction may be more efficient.

[0175] The sixth lens (106) may be arranged to be the sixth from the object side. The sixth lens (106) may be arranged to be the second from the sensor side. The sixth lens (106) may be arranged between the fifth lens (105) and the seventh lens (107). The sixth lens (106) may have a positive (+) refractive power or a negative (-) refractive power on the optical axis (OA). The sixth lens (106) may have a positive (+) refractive power. The sixth lens (106) may include a plastic or glass material. For example, the sixth lens (106) may be arranged to be a plastic material.

[0176] The sixth lens (106) may have a convex object-side eleventh surface (S11) and a concave sensor-side twelfth surface (S12) relative to the optical axis (OA). The sixth lens (106) may have a meniscus shape convex from the optical axis (OA) toward the object side. Alternatively, the sixth lens (106) may have a meniscus shape convex on both sides. At least one or both of the eleventh surface (S11) and the twelfth surface (S12) may be aspherical. The aspherical coefficients of the eleventh surface (S11) and the twelfth surface (S12) may be as follows: Figure 4 L6 is provided by L1 and L2.

[0177] The eleventh surface (S11) of the sixth lens (106) may be arranged to have no critical point from the optical axis (OA) to the far end of the effective area. The twelfth surface (S12) may be arranged to have no at least one threshold point from the optical axis (OA) to the far end of the effective area.

[0178] The seventh lens (107) may be arranged to be closest to the sensor side. The seventh lens (107) may be arranged to be farthest from the object side. The seventh lens (107) may have a positive (+) refractive power or a negative (-) refractive power on the optical axis (OA). The seventh lens (107) may have a negative (-) refractive power. The seventh lens (107) may include a plastic or glass material. For example, the seventh lens (107) may be made of plastic.

[0179] On the optical axis, the object-side thirteenth surface (S13) of the seventh lens (107) may be convex, and the sensor-side fourteenth surface (S14) may be concave. The seventh lens (107) may have a convex meniscus shape on the object side. At least one of the thirteenth surface (S13) and the fourteenth surface (S14) may be aspherical. For example, both the thirteenth surface (S13) and the fourteenth surface (S14) may be aspherical. The aspherical coefficients of the thirteenth surface (S13) and the fourteenth surface (S14) may be as follows: Figure 4 Provided by S1 and S2 of L7.

[0180] The thirteenth surface (S13) of the seventh lens (107) may have a critical point from the optical axis (OA) to the far end of the effective area. If the thirteenth surface (S13) has a critical point, the critical point may be located at more than 50% of the effective radius (r71) at the optical axis OA, or in the range of 52% to 70%, or in the range of 53% to 60%. If the fourteenth surface (S14) has a critical point, the critical point may be located at more than 70% of the effective radius (r72) on the optical axis (OA), or may be located in the range of 70% to 90%, or may be located in the range of 75% to 85%.

[0181] The seventh lens (107) may be a plastic lens that is closest to the image sensor (300). In addition, by arranging two or more plastic lenses adjacent to the image sensor (300), aberrations such as spherical aberration and chromatic aberration may be improved by a lens surface having an aspherical surface, and the effect on resolution may be controlled. In addition, by arranging a plastic lens as a lens adjacent to the image sensor (300), the lens may be insensitive to assembly tolerances compared to a lens made of glass, meaning that even if the lens is assembled with a slight deviation from the design during assembly, the optical performance may not be significantly affected. In addition, by arranging two lenses (106, 107) of plastic adjacent to the image sensor (300), the optical performance may be improved by the aspherical lens surface, for example, by improving aberration characteristics and avoiding a reduction in resolution.

[0182] The sixth lens (106) and the seventh lens (107) are spaced apart but may include features of a cemented lens. The sixth lens (106) and the seventh lens (107) may have opposite refractive powers. The product of the refractive power of the sixth lens (106) and the refractive power of the seventh lens (107) may be less than zero. The product of the focal length of the sixth lens (106) and the focal length of the seventh lens (107) may be less than zero. Therefore, the aberration characteristics of the optical system may be improved. If the refractive powers of the two lenses having cemented lens characteristics are the same, the aberration improvement is limited.

[0183] The sixth lens (106) and the seventh lens (107) may be made of the same material. The sixth lens (106) and the seventh lens (107) may be made of plastic. The sixth lens (106) and the seventh lens (107) may be made of a material different from that of the zoom lens (145). Although the cemented lens (145) is made of glass to improve spherical aberration, the effect of improving aspherical aberration caused by the plastic lens is low. Therefore, the aberration that is not improved by the cemented lens (145) can be improved by setting two additional lenses including the features of the cemented lens made of a material different from that of the cemented lens (145).

[0184] At least one or both of the thirteenth surface (S13) and the fourteenth surface (S14) of the seventh lens (107) may have a critical point. The thirteenth surface (S13) of the seventh lens (107) may have a first critical point (P1) extending from the optical axis (OA) to the far end of the effective area. The first critical point (P1) of the thirteenth surface (S13) may be at least 55% of the effective radius from the optical axis (OA), or may be in the range of 55% to 75%, or may be in the range of 60% to 70%. The first critical point of the thirteenth surface (S13) may be located at a distance of at least 2 mm from the optical axis (OA), for example, at a distance in the range of 2.1 mm to 2.5 mm, or at a distance in the range of 2.2 mm to 2.3 mm. As another example, the thirteenth surface (S13) may be set to have no critical point. The thirteenth surface (S13) having such a first critical point (P1) may refract incident light to the center and the periphery, and may improve aberrations. The first critical point (P1) and the second critical point (P2) are points where the sign of the slope value relative to the optical axis (OA) and the direction perpendicular to the optical axis (OA) changes from positive (+) to negative (-) or from negative (-) to positive (+), which may mean a point where the slope value is zero. In addition, the first critical point (P1) and the second critical point (P2) may be points where the slope value of a tangent line passing through the lens surface (plane) changes from large to small or from small to large.

[0185] The fourteenth surface (S14) of the seventh lens (107) may have at least one second critical point (P2) extending from the optical axis (OA) to the far end of the effective area. The second critical point (P2) of the fourteenth surface (S14) may be located at least 60% of the effective radius (r72) from the optical axis (OA), or in the range of 60% to 80%, or in the range of 65% to 75%. The second critical point (P2) of the fourteenth surface (S14) may be located at a distance exceeding 2.9 mm from the optical axis (OA), for example, in the range of 2.9 mm to 3.9 mm, or in the range of 3.1 mm to 3.7 mm. Therefore, the second critical point (P2) is positioned closer to the edge than the first critical point (P1), so that the seventh lens (107) can refract incident light to the periphery of the image sensor (300).

[0186] The average effective radius of the thirteenth surface (S13) and the fourteenth surface (S14) of the seventh lens (107) can be set to be less than Imgh, where Imgh is 1 / 2 of the diagonal length of the image sensor (300), so that light can be refracted to the periphery of the image sensor (300) through the fourteenth surface (S14) having the second critical point (P2).

[0187] like Figure 2 and Figure 6As shown, Sag41 represents the height from the center of the seventh surface (S7) of the fourth lens (104) to the lens surface in a direction (X, Y) orthogonal to the optical axis (OA), and the maximum value of Sag41 can be the height at the edge of the seventh surface (S7).

[0188] Sag42 represents the height from the center of the eighth surface (S8) of the fourth lens (104) to the lens surface in the direction (X, Y) orthogonal to the optical axis (OA), and the maximum value of Sag42 may be the height at the edge of the eighth surface (S8). Sag52 represents the height from the center of the ninth surface (S9) of the fifth lens (105) to the lens surface in the direction (X, Y) orthogonal to the optical axis (OA), and the maximum value of Sag52 may be the height at the edge of the ninth surface (S9).

[0189] Sag61 represents the height from the center of the eleventh surface (S11) of the sixth lens (106) to the lens surface in the direction (X, Y) orthogonal to the optical axis (OA), and the maximum value of Sag61 may be the height at the edge of the eleventh surface (S11). Sag62 represents the height from the center of the twelfth surface (S12) of the sixth lens (106) to the lens surface in the direction (X, Y) orthogonal to the optical axis (OA), and the maximum value of Sag is the height at the edge.

[0190] The maximum Sag value can meet the following conditions

[0191] Can satisfy Max_Sag51 <Max_Sag52<Max_Sag41。

[0192] The difference between Max_Sag52 and Max_Sag61 may be 0.4 or less. By setting the Sag value between these adjacent glass lenses and plastic lenses, the light loss between the glass lenses and the plastic lenses may be reduced.

[0193] exist Figure 6 In the embodiment of the present invention, if the Sag value is positive, the lens surface (surface) is located on the sensor side relative to the straight line orthogonal to the optical axis (OA), and if the Sag value is negative, the lens surface is located on the object side relative to the straight line orthogonal to the optical axis (OA). In addition, when the object side and the sensor side of each lens are compared, the object side surface and the sensor side surface of the seventh lens (107) may be the sides where the difference between the maximum Sag value and the minimum Sag value is the smallest. This may be because the distance between the object side surface of the seventh lens (107) and the sensor side is constant, and the average value of the curvature radius may be greater than the average value of the curvature radius of the other lenses.

[0194] like Figure 1 and Figure 2As shown, the center thickness of the first to seventh lenses (101 to 107) is represented by CT1 to CT7, the edge thickness at the end of the effective area of ​​each lens is represented by ET1 to ET7, the center gap between two adjacent lenses is represented by CG1 to CG6, and the edge gap between the edges of each lens is represented by EG1 to EG6. Here, the center thickness of the cemented lens (145) is CT45, and the edge thickness is ET45.

[0195] Reference Figure 2 , BFL (back focal length) is the optical axis distance from the image sensor (300) to the center of the last lens. Figure 1 In the embodiment, TTL is the optical axis distance from the center of the first surface (S1) of the first lens (101) to the top (upper) surface of the image sensor (300).

[0196] Figure 3 yes Figure 1 An example of lens data of the optical system of the first embodiment. Figure 3 As shown, the radius of curvature of the first lens to the seventh lens (101, 102, 103, 104, 105, 106, 107) on the optical axis (OA), the thickness of the lens, the distance between the centers of the lenses, the refractive index on the d-line, the Abbe number and the size of the clear aperture (CA) can be set.

[0197] like Figure 4 As shown, in the first exemplary embodiment, the lens surfaces of the first lens (101), the second lens (102), the sixth lens (106), and the seventh lens (107) in the lens of the lens unit (100) may include an aspheric surface having a 30th order aspheric coefficient. For example, the first lens (101), the second lens (102), the sixth lens (106), and the seventh lens (107) may include a lens surface having a 30th order aspheric coefficient. As described above, the aspheric surface having a 30th order aspheric coefficient (a value other than "0") can particularly significantly change the peripheral aspheric geometry, thereby providing good correction of the optical performance of the periphery of the field of view (FOV).

[0198] like Figure 5 As shown, the thickness (T1 to T7) of the first lens to the seventh lens (101, 102, 103, 104, 105, 106, 107) and the distance (G1 to G6) between two adjacent lenses can be set. Figure 5 As shown, for the thickness of each lens in the y-axis direction (T1 to T7), intervals of every 0.1 mm or 0.2 mm or more may be indicated, and for the spacing between each lens (G1 to G6), intervals of every 0.1 mm or 0.2 mm or more may be indicated.

[0199] Reference Figure 3 and Figure 5 , when comparing the absolute value of the radius of curvature of each lens, the radius of curvature of the twelfth surface (S12) of the sixth lens (106) on the optical axis (OA) may be the largest among the lenses, and the radius of curvature of the tenth surface (S10) of the fifth lens (105) may be the smallest among the lenses. The difference between the maximum radius of curvature and the minimum radius of curvature may be 10 times or more, for example, in the range of 15 times to 38 times.

[0200] When describing the center thickness of the lens along the optical axis, the center thickness (CT4) of the fourth lens (104) is the largest among the lenses, and the center thickness (CT1) of the first lens (101) is the smallest among the lenses. The difference between the maximum center thickness and the minimum center thickness of the lens can be in the range of from 1.5 mm to 2.5 mm or more.

[0201] When describing the center spacing (CG) between lenses, the center spacing (CG6) between the sixth lens (106) and the seventh lens (107) may be the largest, and the center spacing between the second lens (102) and the third lens (103) may be the smallest. Here, the minimum center spacing does not include the bonding surface of the cemented lens (145). The difference between the maximum center spacing and the minimum center spacing of the spaced lenses may be at least 1.5 mm, for example, in the range of 2 mm to 3.5 mm. In addition, by setting the maximum center spacing between lenses to be less than or equal to 70% of the maximum center thickness, for example, in the range of 30% to 70%, the thickness of a camera module with a plastic lens having a thin thickness may not be increased without increasing the center spacing relative to the center thickness of each lens.

[0202] When describing the effective diameter, the lens with the largest effective diameter may be disposed between the first lens (101) closest to the object and the seventh lens (107) closest to the image sensor (300). The lens with the largest effective diameter may be a lens made of plastic. The lens with the largest effective diameter may be disposed between the first lens (101) and the cemented lens (145). The lens with the largest effective diameter may be the third lens (103). Here, the effective diameter is the average value of the effective diameter of the object side surface and the effective diameter of the sensor side surface of each lens. The lens surface with the largest effective diameter may be the sixth surface (S6) of the third lens (103) or the object side surface of the cemented lens (145).

[0203] The lens with the smallest effective diameter may be any one of the plastic lenses, such as the seventh lens (107) adjacent to the image sensor (300). For example, the effective diameter of the seventh lens (107) may be the smallest in the lens portion (100). The lens surface with the smallest effective diameter may be the thirteenth surface (S13) of the seventh lens (107).

[0204] The effective diameter of each of the first to fourth lenses (101 to 104) adjacent to the object side may be greater than the effective diameters of the fifth lens (105), the sixth lens (106), and the seventh lens (107) adjacent to the sensor side. The effective diameters of the first to fourth lenses (101 to 104) may be greater than the diagonal length of the image sensor (300). The average effective diameter of the seventh lens (107) may be smaller than the diagonal length of the image sensor (300). Therefore, light incident through a plurality of lenses aligned along the optical axis may be guided to the image sensor (300).

[0205] In terms of refractive index, the first lens (101) has a maximum refractive index of the lens, which may be greater than 1.8, for example, greater than 1.82. Any one or all of the second lens (102) and the sixth lens (106) may have a minimum refractive index among the lenses. For example, the minimum refractive index may be less than 1.6, for example, less than 1.55. The difference between the maximum refractive index and the minimum refractive index may be greater than or equal to 0.2. By providing a glass material high refractive index lens closest to the object, a plastic material low refractive index lens adjacent to the glass material lens, and a lens adjacent to the image sensor (300), the incident efficiency can be improved, and the refractive power between the glass material lens and the plastic material lens can be adjusted to guide light to the image sensor (300).

[0206] When comparing Abbe numbers, the Abbe number of the third lens (103) is the largest among the lenses and may be greater than or equal to 60. The seventh lens has the lowest Abbe number among the lenses, which may be 25 or less. The difference between the maximum refractive index and the minimum Abbe number may be 40 or more. By providing the third lens (103) adjacent to the cemented lens (145) with the largest Abbe number and providing the seventh lens (107) with a low refractive index adjacent to the image sensor (300) with the smallest Abbe number, it is possible to control the dispersion of light passing between the glass lenses and the plastic lens by increasing the dispersion between the glass lenses and the plastic lenses and guide the light to the image sensor (300).

[0207] The focal lengths (F1, F2, F5, F7) of the first lens (101), the second lens (102), the fifth lens (105) and the seventh lens (107) may have a negative (-) sign. The first lens (101), the second lens (102), the fifth lens (105) and the seventh lens (107) may have a negative (-) refractive power. The focal lengths (F3, F4, F6) of the third lens (103), the fourth lens (104) and the sixth lens (106) may have a positive (+) sign. The third lens (103), the fourth lens (104) and the sixth lens (106) may have a positive (+) refractive power. On the sensor side of the first lens (101) and the second lens (102) having negative (-) refractive power, the third lens (103) and the fourth lens (104) having positive (+) refractive power may be provided. This causes light incident from the object side to deviate from the optical axis direction and to converge toward the optical axis direction again, thereby forming a stable light path.

[0208] In addition, adjacent lenses, ie, the sixth lens (106) and the seventh lens (107) may satisfy the following conditions.

[0209] Condition 1: The refractive index of the lens with positive refractive power < the refractive index of the lens with negative refractive power

[0210] Condition 2: The change range of the lens with positive refractive power > the change range of the lens with negative refractive power

[0211] Here, among the plastic lenses, the sixth lens (106) has a positive refractive power, and the seventh lens (107) has a negative refractive power, so that according to conditions 1 and 2, the refractive index of the sixth lens is smaller than the refractive index of the seventh lens, and the variation amplitude of the sixth lens is larger than the variation amplitude of the seventh lens. The chromatic aberration generated by the plastic lens can be corrected by the plastic lens. In addition, the chromatic aberration generated by the plastic lens can be compensated by the plastic lens by satisfying the following: the refractive index difference between the sixth lens (106) and the seventh lens (107) in the continuously arranged plastic lenses is 0.1 or exceeds 0.15 or less, and the Abbe number difference is 20 or exceeds 60 or less.

[0212] The optical system is affected by chromatic aberration, and chromatic aberration is compensated by using a cemented lens or by using two lenses placed in succession. As the temperature changes from low to high, the lens repeatedly contracts and expands. Since lenses of the same material have the same amount of change in lens properties as the temperature changes, it is effective to correct chromatic aberration between lenses of the same material even when the temperature changes. Therefore, in the first exemplary embodiment of the present invention, the fourth lens (104) and the fifth lens (105) are used to correct chromatic aberration generated by a lens made of glass, and the sixth lens (106) and the seventh lens (107) are used to correct chromatic aberration generated by a plastic lens.

[0213] When the fourth lens (104) and the fifth lens (105) are cemented, chromatic aberration caused by the glass lens is compensated by the glass lens by satisfying the following: the refractive index difference is at least 0.1 but not more than 0.15, and the Abbe number difference is at least 20 but not more than 60. The refractive index difference is rounded to the third decimal place, and the Abbe number difference is rounded to the first decimal place to compare these values.

[0214] Furthermore, by placing a glass lens having a relatively high Abbe number on the object side of the plastic lens, dispersion can be reduced by the glass lens and increased by the plastic lens.

[0215] When the focal lengths are compared in absolute value, the focal length of the second lens (102) is the largest among the lenses and may be 55 or more or 100 or more. Among the lenses, the second lens (102) made of plastic may have the largest focal length and the smallest refractive power. The lens with the largest focal length after the second lens (102) may be the first lens (101) made of glass.

[0216] In addition to the first lens (101), the focal lengths of the second lens (102), the sixth lens (106), and the seventh lens (107) made of plastic may be greater than the focal lengths of the third lens (103), the fourth lens (104), and the fifth lens (105) made of glass. The focal length of the fifth lens (105) may be the smallest among the lenses, and may be 15 or less, or 10 or less. Among the lenses, the fifth lens (105) made of glass may have the smallest focal length and the largest refractive power. On the sensor side of the fifth lens (105), a lens made of a plastic material having a smaller refractive power may be provided so that the refractive power of the fifth lens (105) may be increased.

[0217] Among the lenses other than the cemented lens (145), the lens having the minimum focal length may be the sixth lens (106). The difference between the maximum focal length and the minimum focal length may be 50 or more, or 80 or more. Therefore, the optical system may have improved MTF characteristics, aberration control characteristics, resolution characteristics, etc. within a set field of view, and may have good optical performance at the periphery of the field of view.

[0218] There is a critical point on the sensor side surface of the seventh lens (107). The critical point is a point where the trend of the sag value changes, that is, a point where the sag value increases and then decreases, or a point where the sag value decreases and then increases. Figure 6, it can be seen that there is a critical point between a point 1.7 mm away and a point 2.0 mm away in the direction perpendicular to the optical axis on the object side surface of the seventh lens (107). On the object side surface of the seventh lens (107), the sag value increases to a point 1.8 mm away in the direction perpendicular to the optical axis, and then decreases from a point 1.8 mm away in the direction perpendicular to the optical axis to a point 4.2 mm away in the direction perpendicular to the optical axis.

[0219] On the sensor side surface of the seventh lens (107), it can be seen that there is a critical point between a point 3.3 mm apart and a point 3.9 mm apart in the direction perpendicular to the optical axis. On the sensor side surface of the seventh lens (107), the sag value increases to a point 3.4 mm apart in the direction perpendicular to the optical axis, and then decreases from a point 3.4 mm apart in the direction perpendicular to the optical axis to a point 4.6 mm apart in the direction perpendicular to the optical axis. The sensor side surface of the seventh lens (107), that is, the sensor side surface of the last lens, that is, the presence of the critical point on the lens surface closest to the sensor enables TTL to be reduced, thereby facilitating miniaturization and lightweighting of the optical system.

[0220] The thickness (T1) of the first lens (101) may be in the range of 1 to 1.2 times the difference between the maximum thickness and the minimum thickness, for example 1 to 1.2 times or more, wherein the center thickness (CT1) is the maximum and the edge thickness (ET1) is the minimum. The thickness (T2) of the second lens (102) may be in the range of 1 to 1.2 times the maximum thickness of the minimum thickness. The second lens (102) may have a minimum center thickness (CT2) and a maximum edge thickness (ET2). The thickness (T3) of the third lens (103) may be maximum at the center and minimum at the edge, wherein the maximum thickness is in the range of 1.5 to 2 times the minimum thickness. The thickness (T4) of the fourth lens (104) may be maximum at the center and minimum at the edge, wherein the maximum thickness is in the range of 1.9 to 2.2 times the minimum thickness. The thickness (T5) of the fifth lens (105) may be minimum at the center and maximum at the edge, wherein the maximum thickness is in the range of 1.6 to 1.8 times the minimum thickness. The thickness (T6) of the sixth lens (106) may be maximum at the center and minimum at the edge, wherein the maximum thickness is in the range of 1.4 to 1.6 times the minimum thickness. The thickness (T7) of the seventh lens (107) may be minimum at the center and maximum at the edge, wherein the maximum thickness is in the range of 1 to 1.2 times the minimum thickness.

[0221] The center thickness (CT45) of the cemented lens (145) may be greater than the edge thickness (ET45). The center thickness (CT45) of the cemented lens (145) is the distance from the center of the seventh surface (S7) on the object side of the fourth lens (104) to the center of the tenth surface (S10) of the fifth lens (105), and the edge thickness (ET45) is the distance from the far end of the effective area of ​​the seventh surface (S7) to the tenth surface (S10) in the optical axis direction. The maximum thickness of the cemented lens (145) is at the center, the minimum thickness is at the edge, and the maximum thickness may be in the range of 1 to 1.2 times the minimum thickness.

[0222] Among the gaps (spacings) (G1 to G6) between the lenses, the first gap (spacing) (G1) between the first lens (101) and the second lens (102) may be maximum at the center and minimum at the edge. The second gap (G2) between the second lens (102) and the third lens (103) may have a maximum value at the edge and a minimum value at the center. The third gap (G3) between the third lens (103) and the fourth lens (104) may be maximum at the edge and minimum at the center. The fifth gap (G5) between the fifth lens (105) and the sixth lens (106) may be maximum at the center and minimum at the edge. The sixth gap (G6) between the sixth lens (106) and the seventh lens (107) may have a maximum value at the center and a minimum value at the edge.

[0223] like Figure 7 As shown, Figure 1 The chief ray angle (CRA) in the optical system and the camera module can be in the range of 10 degrees or more at 1 field at the far end of the diagonal length of the image sensor, for example, in the range of 10 degrees to 35 degrees, or in the range of 10 degrees to 25 degrees. In addition, the difference in CRA from a low temperature (-40 degrees Celsius) to a high temperature (95 degrees Celsius) can be 1 degree or less. Therefore, even if the temperature changes from a low temperature to a high temperature, the difference in CRA will not be large, and stable optical performance can be achieved. In the optical system according to the first exemplary embodiment, as Fig.14 As shown in the graph of the ambient light ratio or relative illumination according to the image height, it can be seen that the ambient light ratio is 70% or more, for example, 75% or more, from the center of the image sensor to the far end of the diagonal line. In other words, it can be seen that the difference between the ambient light ratios (zoom positions 1, 2, and 3) according to the temperature at normal temperature, low temperature, and high temperature is almost the same as far as 4.5 mm or more from the optical axis.

[0224] Figures 8 to 10 yes Figure 1The graph of the diffraction modulation transfer function (MTF) of the optical system at room temperature, low temperature and high temperature shows the brightness ratio (modulation) as a function of spatial frequency. Figures 8 to 10 As shown, in the first exemplary embodiment of the present invention, the deviation of the MTF from room temperature to low temperature or high temperature may be less than 10%, for example, 7% or less.

[0225] Figure 11 to Figure 12 is for Figure 1 The aberration characteristics of the optical system at room temperature, low temperature and high temperature. Figures 11 to 13 In the aberration graph of , longitudinal spherical aberration, astigmatism field curve, and distortion are measured from left to right. Figures 11 to 13 In the graph, the X-axis may represent the focal length (mm) or the distortion (%), and the Y-axis may represent the height of the image. In addition, the graph of spherical aberration is a graph of light in wavelength bands of about 435 nm, about 486 nm, about 546 nm, about 587 nm, and about 656 nm, and the graph of astigmatism and distortion aberration is a graph of light in a wavelength band of about 546 nm. Figures 11 to 13 The aberration graph of the aberration diagram can explain that the closer each curve at room temperature, low temperature and high temperature is to the Y axis, the better the aberration correction capability, and 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. In other words, the optical system (1000) according to the first embodiment has an improved resolution and can also have good optical performance not only in the center of the field of view (FOV), but also in the periphery. Here, the low temperature may be in the range of -20 degrees Celsius or less, for example in the range of -20 degrees Celsius to -40 degrees Celsius, the room temperature may be in the range of 22 degrees Celsius ± 5 degrees Celsius or 18 degrees Celsius to 27 degrees Celsius, and the high temperature may be in the range of 85 degrees Celsius or more, for example in the range of 85 degrees Celsius to 105 degrees Celsius. Therefore, it can be seen that Figures 11 to 13 The decrease in brightness ratio modulation from low temperature to high temperature is less than 10%, such as 5% or less, or almost no change.

[0226] Table 1 compares the changes in optical properties such as EFL, BFL, F number (F#), TTL and field of view (FOV) of the optical system according to the first embodiment at room temperature, low temperature and high temperature, and it can be seen that the rate of change of the optical properties at low temperature relative to room temperature is 5% or less, for example 3% or less, and the rate of change of the optical properties at high temperature relative to room temperature is 5% or less, for example 3% or less.

[0227] [Table 1]

[0228] Room temperature Low temperature high temperature Low temperature / room temperature High temperature / room temperature EFL(F) 15.1 15.044 15.167 99.63％ 100.44％ BFL 2.869 2.865 2.852 99.87％ 100.14％ F# 1.600 1.594 1.607 99.63％ 100.44％ TTL 32.045 31.990 32.109 99.82％ 100.20％ FOV 34.039 34.160 33.896 100.35％ 99.57％

[0229] Therefore, as shown in Table 1, it can be seen that the change in optical properties, such as the change in effective focal length (EFL), TTL, BFL, F number, and field of view (FOV), due to the change in temperature from low temperature to high temperature is within the range of 0 to 5%, for example, 5% or less. This makes it possible to design for temperature compensation of the plastic lens to prevent the reduction in reliability of the optical properties even in the case of using at least one or more layers of plastic lenses.

[0230] The optical system of the first embodiment disclosed above can effectively control aberration characteristics such as chromatic aberration and distortion aberration, and can have good optical performance not only at the center of the field of view (FOV) but also at the periphery.

[0231] like Fig.15 As shown, the optical system (2000) according to the second exemplary embodiment of the present invention may include five or more lenses. The optical system (2000) and its camera module may be installed inside or outside a vehicle for driver monitoring or for sensing external objects or lanes. The lens may be made of glass or plastic, wherein glass has a smaller linear expansion coefficient than plastic. Therefore, a glass lens is used to suppress changes in the focal imaging position due to temperature changes. However, compared with plastic lenses, glass lenses are expensive, so it is difficult to meet the demand for low cost. Therefore, the lens in the optical system (2000) needs to be composed of a mixture of glass lenses and plastic lenses. By adopting such a plastic lens, the optical system (2000) can provide light weight and low cost due to the reduced thickness of the plastic lens, and the plastic lens can provide good correction for various aberrations such as spherical aberration and chromatic aberration. The plastic lens can also provide an aspherical lens, which can minimize peripheral distortion.

[0232] The optical system (2000) may include n lenses, wherein the n-th lens may be the last lens adjacent to the image sensor (300), and the n-1-th lens may be the lens closest to the last lens. n may be an integer greater than or equal to 5, for example, 5 to 8. The ratio of lenses made of plastic to lenses made of glass in the n lenses may be in the range of 2:3 to 2:6, or in the range of 3:4 to 3:5.

[0233] The optical system (2000) may include a plurality of lens groups (LG1, LG2). More specifically, each of the plurality of lens groups (LG1, LG2) may include at least one lens. For example, the optical system (2000) may include a first lens group (LG1) and a second lens group (LG2) sequentially arranged along an optical axis (OA) from an object side toward an image sensor (300).

[0234] Each of the first lens group (LG1) and the second lens group (LG2) may have a different number of lenses. The number of lenses in the second lens group (LG2) may be greater than the number of lenses in the first lens group (LG1), for example, greater than four times the number of lenses in the first lens group (LG1) or greater than five times the number of lenses in the first lens group (LG1). The first lens group (LG1) may include at least one lens. The first lens group (LG1) may have three or fewer lenses. Preferably, the first lens group (LG1) may be a single lens. The second lens group (LG2) may include two or more lenses. The second lens group (LG2) may include four to seven lenses. Preferably, the second lens group (LG2) may include six lenses.

[0235] The first lens group (LG1) may include at least one lens made of plastic. The first lens group (LG1) may include at least one lens made of glass. The first lens group (LG1) may include a lens made of plastic closest to the object side. By increasing the number of plastic lenses included in the optical system (2000), mass production can be increased, weight can be reduced, and price competitiveness can be achieved.

[0236] The lens material of the second lens group (LG2) may be a mixture of at least one glass lens and at least one plastic lens. In the second lens group (LG2), at least one plastic lens may be arranged closer to the sensor than the glass lens. The second lens group (LG2) may include more than two glass lenses, for example two to four glass lenses. The second lens group (LG2) may include, for example, two to six lenses. As another example, the second lens group (LG2) may have at least one lens made of plastic. The second lens group (LG2) may include more than two plastic lenses, for example two to four plastic lenses.

[0237] At least 15 lenses closest to the object in the optical system (2000) can be made of glass. Three or more lenses, such as three to five lenses, closest to the object can be made of glass. Because the rate of change of contraction and expansion of glass lenses with temperature changes is less than that of plastic lenses, glass lenses can be placed in the outer adjacent area within the lens barrel.

[0238] At least one lens closest to the image sensor (300) in the optical system (2000) may be made of plastic. For example, at least two lenses closest to the image sensor (300) may be made of plastic, and preferably, at least two lenses adjacent to the image sensor (300) may be made of plastic. In other words, the nth lens and the n-1th lens in the optical system (2000) may be set as plastic lenses to compensate for various aberrations of light incident on the image sensor (300).

[0239] In the optical system (2000), plastic lenses may be arranged in series (back to back), and glass lenses may be arranged in series (back to back). In the optical system (2000), lenses made of plastic may be arranged between lenses made of glass. In the optical system (2000), glass lenses may be arranged between plastic lenses.

[0240] Each lens (201 to 207) may have an object side surface and a sensor side surface. In the optical system, the number of lenses having an aspherical sensor side surface and an aspherical object side surface may be greater than the number of plastic lenses. The optical system may have a spherical sensor side surface and a spherical object side surface, and the number of lenses may be less than the number of lenses having aspherical surfaces on both sides. The optical system (2000) may have more aspherical lenses than spherical lenses to compensate for various aberrations.

[0241] In the optical system (2000), a lens having a maximum effective diameter may be disposed at the center of the object side and the sensor side. The effective diameter of the lens may increase and decrease from the object side to the sensor side. As the lens moves from the object side to the sensor side, the effective diameter of the lens may become smaller, then larger, and then smaller again. Because light incident on the optical system (2000) moves away from the optical axis and then converges back to the optical axis, this allows the optical system (2000) to form a stable optical path.

[0242] The effective diameter may be the diameter of the effective area where light is incident on each lens. The effective diameter is the length in the direction (X, Y) orthogonal to the optical axis, and is the average of the effective diameter of the object side surface and the effective diameter of the sensor side surface of each lens. "The diameter of the lens face (surface)" may mean "the effective diameter of the lens". "The diameter of the lens" may be the diameter of the entire lens, including the flange portion of the lens in addition to the effective area of ​​the lens. Although Fig.15 and Fig.16 The flange of the lens is not shown in the figure, but the flange can be a part protruding from the side of the lens perpendicular to the optical axis, which is used to couple the lens to the lens barrel. The flange may not receive effective light. Additional spacers can be set between the flanges of different lenses to allow the lens to be coupled to the lens barrel.

[0243] Each of the lenses (201 to 207) may include an effective area and an ineffective area. The effective area may be an area through which light incident on each lens in the lens passes, i.e., the effective area may be defined as an effective area or effective diameter through which incident light is refracted to produce optical properties. The ineffective area may be arranged around the periphery of the effective area. The ineffective area may be an area where no effective light is incident on the plurality of lenses, i.e., the ineffective area may be an area that is unrelated to the optical properties. In addition, the distal end of the ineffective area may be an area to which a lens barrel or the like that houses the lenses is fixed.

[0244] In the optical system (2000), the total top length (TTL) can be more than two times of Imgh, for example more than four times but less than twelve times. The total track length (TTL) is the distance from the center of the object side surface of the first lens on the optical axis (OA) to the upper (top) surface of the image sensor 300. Imgh is the distance on the optical axis (OA) to the diagonal end of the image sensor (300), or 1 / 2 of the maximum diagonal length. In the optical system (2000), an effective focal length (EFL) of at least 10 mm and a field of view (FOV) of less than 45 degrees can be provided, which can be provided by a standard optical system in an automotive camera module. For example, the optical system and camera module according to the embodiment can be applied to a camera of an advanced driver assistance system (ADAS) inside or outside a vehicle.

[0245] The optical system (2000) may have a TTL / Imgh condition of at least 5 and at least 7.5, for example, at least 6 and at least 7. By allowing the optical system (2000) to set the value of TTL / Imgh to be greater than or equal to 5 and less than or equal to 7.5 times, an automotive lens optical system may be provided. The total number of lenses in the first lens group (LG1) and the second lens group (LG2) may be 8 or less. Therefore, the optical system (2000) may provide an image without exaggeration or distortion for analyzing the image.

[0246] The effective diameter of at least one plastic lens in the optical system (2000) may be smaller than the length of the image sensor (300). The effective diameter is the diameter or length of the effective area through which light is incident. The length of the image sensor (300) is the maximum length of a diagonal line in a direction orthogonal to the optical axis (OA). In the optical system (2000), the number of lenses having an effective diameter greater than the length of the image sensor (300) may be greater than 50% or greater than 60%, and the number of lenses having an effective diameter less than the length of the image sensor (300) may be less than 50% or less than 40%.

[0247] The optical system (2000) may include at least one cemented lens (245) therein. The cemented lens (245) is a cementation of at least two lenses with different refractive powers, wherein the gap (spacing) between the two lenses may be less than 0.01 mm. The cemented lens 245 may be a lens in which two lenses with different focal lengths are laminated. The bonding of the two lenses may be bonded with an adhesive. The effective diameter of at least one lens or all lenses disposed on the object side relative to the cemented lens (245) may be greater than the length of the image sensor (300). The effective diameter of at least one lens disposed on the sensor side relative to the cemented lens (245) may be less than the length of the image sensor (300). In addition, the object side lens (203) of the cemented lens (245) may be greater than the length of the image sensor (300), and the sensor side lens (204) may be greater than the length of the image sensor (300).

[0248] The lens between the cemented lens (245) and the first lens (201) can be made of glass or plastic. The lens arranged between the cemented lens (245) and the image sensor (300) can be made of plastic. The lens between the cemented lens (245) and the first lens (201) can be two-surface spherical or two-surface aspherical. The lens arranged between the cemented lens (245) and the image sensor (300) can be a two-surface aspherical lens. The two surfaces are the object side surface and the sensor side surface. Therefore, by arranging an aspherical lens between the cemented lens (245) and the image sensor (300), the optical performance can be improved by correcting the curvature aberration and the chromatic aberration.

[0249] On the optical axis (OA), the first lens group (LG1) and the second lens group (LG2) may have a set spacing. The optical axis spacing between the first lens group (LG1) and the second lens group (LG2) in the optical axis (OA) direction may be an optical axis spacing between a sensor side surface of a lens closest to the sensor side among the lenses in the first lens group LG1 and an object side surface of a lens closest to the object side among the lenses in the second lens group (LG2). The optical axis spacing between the first lens group (LG1) and the second lens group (LG2) may be less than or equal to 1 times the optical axis distance of the first lens group (LG1), for example, in a range of 0.1 times to 1 times the optical axis distance of the first lens group (LG1).

[0250] The optical axis distance between the first lens group (LG1) and the second lens group (LG2) may be less than or equal to 0.2 times the optical axis distance of the second lens group (LG2), for example, in the range of 0.01 times to 0.2 times. The optical axis distance of the second lens group (LG2) is the optical axis distance between the object side surface of the lens closest to the object side in the second lens group (LG2) and the sensor side surface of the lens closest to the image sensor (300).

[0251] Here, among the lens surfaces of the first lens group (LG1) and the second lens group (LG2), two surfaces facing each other, for example, the sensor side surface of the object side lens may be concave and the object side surface of the sensor side lens may be concave, that is, the sensor side surface closest to the sensor side in the first lens group (LG1) may be concave and the object side surface closest to the object side in the second lens group (LG2) may be concave. The first lens group (LG1) may diffuse light incident through the object side, and the second lens group (LG2) may refract light diffused by the first lens group (LG1) to an area of ​​the image sensor (300).

[0252] The first lens group (LG1) may have a negative (-) refractive power, and the second lens group (LG2) may have a positive (+) refractive power. Among the lenses of the first lens group (LG1), the lens closest to the object side may have a negative (-) refractive power, and among the lenses of the second lens group (LG2), the lens closest to the sensor side may have a negative (-) refractive power. When the focal length is expressed as an absolute value, the focal length of the first lens group (LG1) may be greater than the focal length of the second lens group (LG2), for example, 2 times greater, for example, in the range of 50 times to 100 times. The effective focal length (EFL) of the optical system (2000) may be less than the absolute value of the focal length of the first lens group (LG1). The effective focal length EFL of the optical system (2000) may be less than the absolute value of the focal length of the first lens group (LG1) and greater than the absolute value of the focal length of the second lens group (LG2).

[0253] In the optical system (2000), the number of lenses having positive (+) refractive power may be equal to or greater than the number of lenses having negative (-) refractive power. The number of lenses having positive (+) refractive power may account for 50% or more of the total number of lenses. The average refractive index of lenses having negative (-) refractive power may be greater than the average refractive index of lenses having positive (+) refractive power. Therefore, the variation range of lenses having positive (+) refractive power may be greater than the variation range of lenses having negative (-) refractive power.

[0254] The lens portion (200) may include a mixture of glass lenses and plastic lenses. The number of plastic lenses may be 60% or less of the total number of lenses, for example, in the range of 30% to 60%, or in the range of 30% to 57%. Therefore, when more plastic lenses are provided in the camera module, the weight of the camera module may be reduced, and the plastic material may be easily polished, processed, and resistant to external impact, and the price is competitive and the material is easy to fix. In addition, various aberrations may be corrected by the plastic lens, thereby preventing a reduction in optical performance.

[0255] Embodiments of the present invention may also incorporate plastic lenses into the optical system (2000), which may reduce the weight of the camera module, may provide lower manufacturing costs, may suppress degradation of optical properties due to temperature changes, may allow various types of plastic lenses to replace glass lenses, and may facilitate polishing and processing of lens surfaces such as aspheric surfaces or freely curved surfaces.

[0256] The lens portion (200) may include a lens of a first material and a lens of a second material arranged along an optical axis (OA). The first material may be glass, and the second material may be plastic. The lens of the first material may be arranged between the lenses of the second material. The lens of the second material may be arranged between the lenses of the first material.

[0257] The lens part (200) may include a second material lens having an aspherical surface along an optical axis (OA), a first material lens having a spherical surface, and a second material lens having an aspherical surface. The first material may be a glass material and the second material may be a plastic material.

[0258] In the lens unit (200), the effective diameter of the lens closest to the object side may be larger than the effective diameter of the lens closest to the image sensor (300). Therefore, the brightness of the optical system can be controlled. The effective diameter may be the average effective diameter of the object side surface and the sensor side surface of each lens. By controlling the size of the effective diameter of each lens, the optical system (2000) can control incident light to compensate for the reduction of optical properties due to changes in resolution and temperature, improve chromatic aberration control characteristics, and improve the vignetting characteristics of the optical system (2000).

[0259] The lens section (200) may include a first lens 201, a second lens 202, a third lens 203, a fourth lens 204, a fifth lens 205, a sixth lens 206, and a seventh lens 207 aligned along the optical axis from the object side toward the sensor side.

[0260] The number of lenses in the lens unit (200) that are larger than the average effective diameter of the plastic lens can be three or more, such as four or more. If the average effective diameter of the plastic lens is PLca_Aver and the average effective diameter of the glass lens is GLca_Aver, the condition PLca_Aver < GLca_Aver can be satisfied. In addition, the condition 1 < GLca_Aver / PLca_Aver < 1.5 can be satisfied. In addition, the relationship between the length of the image sensor (300) and the average effective diameter (PLca_Aver) of the plastic lens can satisfy the condition 1 ≤ PLca_Aver / (Imgh*2) < 1.5. In addition, the relationship between the average effective diameter of the glass material and the length of the image sensor (300) can satisfy the condition 1.1 < GLca_Aver / (Imgh*2) < 1.5. The difference between the maximum length of the image sensor (300) and the effective diameter of the plastic lens can be set to be tiny. Therefore, by arranging a plastic lens with a small effective diameter near the image sensor (300), the plastic lens can distribute the color from the center to the periphery of the image sensor (300).

[0261] The glass material can have an average effective diameter of at least 10 mm, for example, in the range of 10 mm to 15 mm. The plastic material can have an average effective diameter of at least 8 mm, for example, in the range of 8 mm to 12 mm. The lens with the smallest effective diameter can be made of plastic, and the lens with the largest effective diameter can be made of glass. Inside the lens unit (200), the smallest effective diameter can be in the range of 7 mm to 10 mm, and the largest effective diameter can be in the range of 11 mm to 15 mm. The lens made of plastic can be designed to have a smaller effective diameter than the lens made of glass, so that the lens made of plastic can be positioned away from the lens barrel, thereby minimizing the change in optical performance caused by temperature changes. In addition, the optical system (2000) can control the incident light to improve the resolution, chromatic aberration control characteristics, and vignetting characteristics of the optical system (2000).

[0262] The optical system (2000) or the imaging device module can include an image sensor (300). The image sensor (300) can detect light and convert it into an electrical signal. The image sensor (300) can detect the light that sequentially passes through the lens unit (200). The image sensor (300) can include elements capable of detecting incident light, such as a charge-coupled device (CCD) or a complementary metal-oxide semiconductor (CMOS).

[0263] Here, the length of the image sensor (300) is the maximum length in the diagonal direction orthogonal to the optical axis (OA), and may be smaller than the effective diameter of the lens closest to the object in the first lens group (LG1), and larger than the effective diameter of the lens closest to the sensor in the second lens group (LG2). Here, the number of lenses having an effective diameter larger than the length of the image sensor (300) may be from 4 to 6, and the number of lenses having an effective diameter smaller than the length of the image sensor (300) may be from 1 to 3.

[0264] The optical system (2000) or the camera 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 (200) and the image sensor (300). For example, the filter (500) may be disposed between the nth lens and the image sensor (300).

[0265] The cover glass (400) may be disposed between the filter (500) and the image sensor (300), and may protect the top of the image sensor (192) and prevent the reliability of the image sensor (192) from being reduced. The cover glass (400) may be removable. The cover glass (400) may be a protective glass.

[0266] The filter (500) may include an infrared filter or an infrared cut filter (IR cut). The filter (500) may allow light of a set wavelength band to pass through and filter out light of a different wavelength band. If the filter (500) includes an infrared filter, it may block radiant heat emitted from external light from reaching the image sensor (300). In addition, the filter (500) may transmit visible light and reflect infrared light.

[0267] The optical system (2000) according to an exemplary embodiment may include an aperture. The aperture may adjust the amount of light incident on the optical system (2000). For a lens disposed between an object and the aperture, the effective diameter of the lens surface tends to increase from the object side toward the aperture. For a lens surface placed between the aperture and the sensor, the effective diameter of the lens surface tends to decrease from the aperture toward the sensor side. The meaning that the effective diameter of the lens surface tends to increase or decrease does not mean that the effective diameter of the lens surface only increases or decreases. For example, the effective diameter of the lens surface may first increase and then decrease from the aperture to the sensor side.

[0268] The aperture may be set at a set position. For example, the aperture may be set around the periphery of the object side surface or the sensor side surface of the lens closest to the object side in the second lens group (LG2). Alternatively, the aperture may be set around the periphery of the object side surface or the sensor side surface of the object-facing lens of the first lens group (LG1). Alternatively, at least one lens selected from a plurality of lenses may be used as the aperture. More specifically, the object side surface or the sensor side surface of at least one lens selected from a plurality of lenses of the optical system (2000) may be used as the aperture to adjust the amount of light.

[0269] In the optical system (2000) according to an exemplary embodiment of the present invention, the sum of the refractive indices of the lenses of the lens portion (200) may be at least 8, for example, in the range of 8 to 15, and the average value of the refractive indices may be in the range of 1.58 to 1.7. The sum of the Abbe numbers of each lens in the lens may be greater than or equal to 300, for example, in the range of 310 to 350, and the average value of the Abbe numbers may be less than or equal to 50, for example, in the range of 35 to 47. The sum of the center thicknesses of all lenses may be in the range of 18 mm or more, for example, in the range of 20 mm to 25 mm, and the average value of the center thicknesses may be in the range of 2.8 mm to 3.5 mm. The sum of the center spacings (gaps) between the lenses on the optical axis (OA) may be at least 6 mm, for example, in the range of 6.8 mm to 8 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 (S1 to S14) of the lens portion (200) may be provided in the range of 8 mm or more, for example, in the range of 8 mm to 15 mm.

[0270] In an optical system according to an embodiment of the present invention, the field of view (diagonal) may be 50 degrees or less, for example, in the range of 20 to 50 degrees. The F number of the optical system or camera module may be 2.4 or less, for example, in the range of 1.4 to 2.4, or in the range of 1.5 to 1.8. In an optical system according to an embodiment of the present invention, the maximum field of view (diagonal) may be 50 degrees or less, for example, in the range of 20 to 50 degrees.

[0271] In an automotive optical system, the horizontal field of view (FOV_H) in the Y-axis direction may be greater than 20 degrees and less than 40 degrees, for example, in the range of 25 to 35 degrees. In addition, the vertical field of view may be provided at a smaller angle than the horizontal field of view, and may be less than 20 degrees, for example, in the range of 10 to 20 degrees. In this case, the sensor length in the horizontal direction (Y) may be 8.064 mm ± 0.5 mm, and the sensor height in the vertical direction (X) may be 4.54 mm ± 0.5 mm. The horizontal field of view (FOV_H) is a field of view based on the horizontal length of the sensor. Therefore, changes in the focus image formation position due to changes in temperature can be suppressed, and the vehicle camera device can be provided with good correction of various aberrations.

[0272] Since the embodiment is an optical system applied to a vehicle camera device, the object side surface of the first lens (201) can have a slightly curved surface shape to better prevent scratches caused by foreign objects placed inside the vehicle and avoid contact with external structures. This can minimize the occurrence of scratches due to contact with external structures. The field of view can be greater than 20 degrees and less than 40 degrees, for example, in the range of 25 degrees to 35 degrees, for driver monitoring during vehicle operation, front and rear views or lane detection of the vehicle, and detection of unexpected objects around the vehicle. This horizontal field of view can be a preset angle for an advanced driver assistance system (ADAD).

[0273] The optical system (2000) according to the embodiment may further include a reflective member for changing the light path. The reflective member may be implemented as a prism that reflects incident light from the first lens group (LG1) in the direction of the lens. Hereinafter, the optical system according to the exemplary embodiment will be described in detail.

[0274] An optical system according to a second exemplary embodiment of the present invention will be described.

[0275] Fig.15 is a side cross-sectional view of an optical system and an imaging device module thereof according to a second embodiment, Fig.16 It shows that according to Fig.15 A side cross-sectional view showing the relationship between the n-th lens and the n-1-th lens, Fig.17 It is shown Fig.15 Table of lens characteristics of optical systems, Fig.18 It is shown Fig.15 Table of aspheric coefficients of lenses in optical systems, Fig.19 It is shown Fig.15 A table showing the thickness of each lens of the optical system and the spacing between adjacent lenses. Fig. 20 It is shown Fig.15 Table of Sag values ​​of lens surfaces of the third lens to the sixth lens of the optical system, Fig.21It is shown based on Fig.15 A table of data of chief ray angles (CRA) at room temperature, low temperature, and high temperature for the position of the image sensor in the optical system, Fig. 22 It is shown Fig.15 The graph of the diffraction MTF (Modulation Transfer Function) data of the optical system at room temperature is shown in Figure 2. Fig.23 It is shown Fig.15 The graph of the diffraction MTF data of the optical system at low temperature, Fig.24 It is shown Fig.15 The graph of the diffraction MTF data of the optical system at high temperature, Fig.25 It is shown Fig.15 A graph showing the aberration characteristics of an optical system at room temperature. Fig.26 It is shown Fig.15 A graph showing the aberration characteristics of an optical system at low temperatures. Fig. 27 It is shown Fig.15 A graph of data on aberration characteristics of an optical system at high temperatures, and Fig.28 is a graph showing relative illuminance based on the height of the image sensor according to the second exemplary embodiment.

[0276] Now refer to Figures 15 to 18 The optical system (2000) may include a lens unit (200), and the lens unit (200) may include a first lens (201) to a seventh lens (207). The first lens (201) to the seventh lens (207) may be sequentially arranged along an optical axis (OA) of the optical system (2000). Light corresponding to information about an object may be incident on an image sensor (300) after passing through the first lens (201) to the seventh lens (207) and the filter (500).

[0277] The first lens (201) may be a lens closest to the object side in the first lens group (LG1). The seventh lens (207) may be a lens closest to the image sensor (300) in the second lens group (LG2) or the lens unit (200). The first lens (201) may be the first lens group (LG1), and the second to seventh lenses (202, 203, 204, 205, 206, 207) may be the second lens group (LG2). An aperture may be provided at the periphery of the object side surface or the sensor side surface of the first lens (201) or at the periphery of the object side surface or the sensor side surface of the second lens (202). For example, an aperture (stop) may be provided at the periphery of the object side surface of the second lens (202).

[0278] The first lens (201) may be arranged to be closest to the object side. The first lens (201) may be arranged to be farthest from the sensor side. The first lens (201) may have a negative (-) refractive power on the optical axis (OA). The first lens (201) may include a plastic material or a glass material, for example, a plastic material.

[0279] Relative to the optical axis, the object-side first surface (S1) of the first lens (201) may be convex, and the sensor-side second surface (S2) may be concave. The first lens (201) may have a convex meniscus shape toward the object side. The first lens (201) may be made of plastic and may have an aspherical surface. At least one or both of the first surface (S1) and the second surface (S2) may be aspherical. The aspherical coefficients of the first surface (S1) and the second surface (S2) may be given by Fig.18 L1S1 and L1S2 are given in .

[0280] Since the first lens (201) has a negative (-) refractive power, the first lens can refract incident light in a direction away from the optical axis (OA) and reduce the gap between the first lens (201) and the second lens (202). In addition, the effective diameter of the sensor side surface of the second lens (202) can be designed to be smaller than the effective diameter of the object side surface by the shape of the lens surface of the first lens (201). The first surface (S1) of the first lens (201) can be set to have no critical point from the optical axis (OA) to the far end, i.e., the edge, of the effective area. The second surface (S2) of the first lens (201) can be set to have no critical point.

[0281] The second lens (202) may be arranged second from the object side. The second lens (202) may be arranged sixth from the sensor side. The second lens (202) may be arranged between the first lens (201) and the third lens (203). The second lens (202) may have a positive (+) refractive power on the optical axis (OA). The second lens (202) may include a plastic or glass material. For example, the second lens (202) may be provided in a plastic material.

[0282] The object-side third surface (S3) of the second lens (202) may be concave and the sensor-side fourth surface (S4) may be convex relative to the optical axis (OA). The second lens (202) may have a convex meniscus shape toward the sensor side. The second lens (202) may be made of plastic and may be aspherical. At least one or both of the third surface (S3) and the fourth surface (S4) may be aspherical. The aspherical coefficients of the third surface (S3) and the fourth surface (S4) may be as follows: Fig.18At least one or both of the third surface (S3) and the fourth surface (S4) may be configured to have no critical point from the optical axis (OA) to the far end of the effective area.

[0283] An aperture (stop) may be provided around the periphery of the third surface (S3) on the object side of the second lens (202). The composite focal length of the second lens (202) to the seventh lens (207) provided on the sensor side of the aperture may have a positive (+) value, which may reduce the TTL within the field of view and achieve miniaturization of the optical system. Therefore, the weight yield of the optical system may be prevented from being reduced, and production efficiency may be improved. In addition, the TTL may be reduced by reducing the horizontal field of view (FOV_H) from 25 degrees to 36 degrees, so as to miniaturize the optical system.

[0284] The third lens (203) may be arranged to be the third from the object side. The third lens (203) may be arranged to be the fifth from the sensor side. The third lens (203) may be arranged between the second lens (202) and the fourth lens (204). The third lens (203) may have a positive (+) refractive power on the optical axis (OA). The third lens (203) may include a plastic or glass material. For example, the third lens (203) may be provided in a glass material.

[0285] Relative to the optical axis, the object-side fifth surface (S5) of the third lens (203) may be convex, and the sensor-side sixth surface (S6) may be convex. The third lens (203) may have a convex shape on both surfaces on the optical axis (OA). By providing a convex shape on both surfaces of the third lens (203), the TTL and the number of lenses in the optical system can be minimized, and light can be refracted efficiently. The third lens (203) may be made of glass and may be spherical. At least one or both of the fifth surface (S5) and the sixth surface (S6) may be spherical. At least one or both of the fifth surface (S5) and the sixth surface (S6) may be arranged to have no critical point from the optical axis (OA) to the far end of the effective area.

[0286] The fourth lens (204) may be arranged to be fourth on the object side. The fourth lens (204) may be arranged to be fourth on the sensor side. The fourth lens (204) may be arranged between the third lens (203) and the fifth lens (205). The fourth lens (204) may have a positive (+) refractive power or a negative (-) refractive power on the optical axis (OA). The fourth lens (204) may have a positive (+) refractive power. The fourth lens (204) may have a positive (+) refractive power different from the refractive power of the fifth lens (205). The fourth lens (204) may include a plastic or glass material. For example, the fourth lens (204) may be provided in a glass material. The fourth lens (204) may be provided in the same material as that of the fifth lens (205).

[0287] Relative to the optical axis, the object-side seventh surface (S7) of the fourth lens (204) may be convex, and the sensor-side eighth surface (S8) may be concave. The fourth lens (204) may have a convex meniscus shape toward the object side. The fourth lens (204) may be made of glass and may have a spherical surface. At least one or both of the seventh surface (S7) and the eighth surface (S8) may be spherical. The seventh surface (S7) and the eighth surface (S8) may be arranged to have no critical point from the optical axis (OA) to the far end of the effective area.

[0288] The fifth lens (205) may be arranged to be fifth from the object side. The fifth lens (205) may be arranged to be third from the sensor side. The fifth lens (205) may be arranged between the fourth lens (204) and the sixth lens (206). The fifth lens (205) may have a positive (+) refractive power or a negative (-) refractive power on the optical axis (OA). The fifth lens (205) may have a negative (-) refractive power. The fifth lens (205) may have a negative (-) refractive power different from the refractive power of the fourth lens (204). The fifth lens (205) may include a plastic or glass material. For example, the fifth lens (205) may be provided in a glass material. The fifth lens (205) may be provided in the same material as that of the fourth lens (204).

[0289] Relative to the optical axis (OA), the fifth lens (205) may be convex on the object side ninth surface (S9) and may be concave on the sensor side tenth surface (S10). The fifth lens (205) may have a convex meniscus shape toward the object side. The fifth lens (205) may be made of glass and may have a spherical surface. At least one of the ninth surface (S9) and the tenth surface (S10) may be spherical. For example, both the ninth surface (S9) and the tenth surface (S10) may be spherical. At least one or both of the ninth surface (S9) and the tenth surface (S10) of the fifth lens (205) may be arranged to have no critical point from the optical axis (OA) to the far end of the effective area.

[0290] The fourth lens (204) and the fifth lens (205) may be cemented. The bonding surface between the fourth lens (204) and the fifth lens (205) may be defined as an eighth surface (S8). The eighth surface (S8) may be the same surface as the ninth surface (S9) of the fifth lens (205). The object side surface of the cemented lens (245) may be convex, and the sensor side surface may be concave. The spacing (gap) between the fourth lens (204) and the fifth lens (205) may be less than 0.01 mm, and may be bonded with an adhesive. From the optical axis (OA) to the far end of the effective area, the spacing between the fourth lens (204) and the fifth lens (205) may be less than 0.01 mm. The fourth lens (204) and the fifth lens (205) may have opposite refractive powers. The composite refractive power of the fourth lens (204) and the fifth lens (205) may have a negative (-) refractive power.

[0291] The value of the radius of curvature of the cemented surface (S8) of the cemented lens (245) may be greater than 30. For example, the value of the radius of curvature of the cemented surface (S8) of the cemented lens (245) may be greater than 50. The cemented surface (S8) of the cemented lens (245) may be formed with a gentle shape. Thus, the bonding process of the fourth lens (204) and the fifth lens (205) forming the cemented lens (245) is favorable, and the bonding holding force can be improved.

[0292] The product of the refractive power of the fourth lens (204) on the object side of the cemented lens (155) and the refractive power of the fifth lens (205) on the sensor side can be less than zero. The product of the focal length of the fourth lens (204) on the object side of the cemented lens (155) and the focal length of the fifth lens (205) on the sensor side of the cemented lens (155) can be less than zero. This can improve the aberration characteristics of the optical system. If the two lenses of the cemented lens (155) have the same refractive power, the aberration improvement is limited.

[0293] With respect to the cemented lens (245), the third lens (203) on the object side and the sixth lens (206) on the sensor side may have positive (+) refractive power. Thus, the third lens (203), the cemented lens (245), and the sixth lens (206) may refract a part of the incident light in the optical axis direction and may correct chromatic aberration with each other. With respect to the cemented lens (245), the focal length of the third lens (203) provided on the object side may be smaller than the focal length of the sixth lens (206) provided on the sensor side. With respect to the cemented lens (245), the refractive power of the third lens (203) provided on the object side may be greater than the refractive power of the sixth lens (206) provided on the sensor side.

[0294] The effective diameter of the fourth lens (204) may be larger than the diagonal length of the image sensor (300). The effective diameter of the fourth lens (204) is the average of the effective diameters of the seventh surface (S7) and the eighth surface (S8) and may be larger than the diagonal length of the image sensor (300). The effective diameter of the fifth lens (205) is smaller than the effective diameter of the fourth lens (204) and may be larger than the diagonal length of the image sensor (300).

[0295] If the effective diameter of the seventh surface (S7) of the fourth lens (204) is CA_L4S1 and the effective diameter of the eighth surface (S8) is CA_L4S2, the effective diameters of the seventh surface (S7) and the eighth surface (S8) may satisfy the condition of 1 < CA_L4S1 / CA_L4S2 < 1.5. If the effective diameter of the ninth surface (S9) of the fifth lens (205) is CA_L5S1 and the effective diameter of the tenth surface (S10) is CA_L5S2, the effective diameters of the ninth surface (S9) and the tenth surface (S10) may satisfy the condition of 1 < CA_L5S1 / CA_L5S2 < 1.5.

[0296] The cemented lens (245) is cemented with glass lenses having different refractive indices from each other and has spherical refracting surfaces, and if an aspherical lens or a plastic lens is employed, the lens provided on the sensor side of the cemented lens (245) may compensate for spherical aberration. Further, if the lens provided on the sensor side of the cemented lens (245) is a plastic lens and has a small effective diameter, the plastic lens may be configured to effectively guide light through the plastic lens to the image sensor (300). The positioning of the cemented lens (245) may be in the middle or behind any two consecutive lenses among the third lens or the sixth lens in the lens unit (200), which may allow more efficient chromatic aberration correction.

[0297] The sixth lens (206) may be arranged to be the sixth from the object side. The sixth lens (206) may be arranged to be the second from the sensor side. The sixth lens (206) may be arranged between the fifth lens (205) and the seventh lens (207). The sixth lens (206) may have a positive (+) refractive power or a negative (-) refractive power on the optical axis (OA). The sixth lens (206) may have a positive (+) refractive power. The sixth lens (206) may include a plastic or glass material. For example, the sixth lens (206) may be provided in a plastic material.

[0298] The sixth lens (206) may be convex on the object-side eleventh surface (S11) and may be concave on the sensor-side twelfth surface (S12) relative to the optical axis (OA). The sixth lens (206) may have a meniscus shape that is convex from the optical axis (OA) toward the object side. Alternatively, the sixth lens (206) may have a meniscus shape that is convex on both surfaces. At least one or both of the eleventh surface (S11) and the twelfth surface (S12) may be aspherical. The aspherical coefficients of the eleventh surface (S11) and the twelfth surface (S12) may be as follows: Fig.18 L6 is provided by L1 and L2.

[0299] The eleventh surface (S11) of the sixth lens (206) may be arranged to have no critical point from the optical axis (OA) to the far end of the effective area. The twelfth surface (S12) may be arranged to have no at least one critical point from the optical axis (OA) to the far end of the effective area.

[0300] The seventh lens (207) may be arranged closest to the sensor side. The seventh lens (207) may be arranged farthest from the object side. The seventh lens (207) may have a positive (+) refractive power or a negative (-) refractive power on the optical axis (OA). The seventh lens (207) may have a negative (-) refractive power. The seventh lens (207) may include a plastic or glass material. For example, the seventh lens (207) may be made of plastic.

[0301] On the optical axis, the object-side thirteenth surface (S13) of the seventh lens (207) may be convex, and the sensor-side fourteenth surface (S14) may be concave. The seventh lens (207) may have a convex meniscus shape on the object side. At least one of the thirteenth surface (S13) and the fourteenth surface (S14) may be aspherical. For example, both the thirteenth surface (S13) and the fourteenth surface (S14) may be aspherical. The aspherical coefficients of the thirteenth surface (S13) and the fourteenth surface (S14) may be as follows: Fig.18 Provided by S1 and S2 of L7.

[0302] The thirteenth surface (S13) of the seventh lens (207) may have a critical point from the optical axis (OA) to the far end of the effective area. If the thirteenth surface (S13) has a critical point, the critical point may be located at least 50% of the effective radius (r71) from the optical axis (OA), or in the range of 52% to 70%, or in the range of 53% to 60%. If the fourteenth surface (S14) has a critical point, the critical point may be located at least 70% of the effective radius (r72) on the optical axis (OA), or in the range of 70% to 90%, or in the range of 75% to 85%.

[0303] The seventh lens (207) may be a plastic lens that is closest to the image sensor (300). In addition, by placing two or more plastic lenses adjacent to the image sensor (300), aberrations such as spherical aberration and chromatic aberration may be improved by a lens surface having an aspherical surface, and the effect on resolution may be controlled. In addition, by providing a plastic lens as a lens adjacent to the image sensor (300), the lens may be insensitive to assembly tolerances compared to a lens made of glass, meaning that even if the lens is assembled to have a slight deviation from the design during assembly, the optical performance may not be significantly affected. In addition, by providing two lenses (206, 207) of plastic adjacent to the image sensor (300), the optical performance may be improved by, for example, improving aberration characteristics and avoiding a reduction in resolution through an aspherical lens surface.

[0304] The sixth lens (206) and the seventh lens (207) may be spaced apart but may include features of a cemented lens. The sixth lens (206) and the seventh lens (207) may have opposite refractive powers. The product of the refractive power of the sixth lens (206) and the refractive power of the seventh lens (207) may be less than zero. The product of the focal length of the sixth lens (206) and the focal length of the seventh lens (207) may be less than zero. Therefore, the aberration characteristics of the optical system may be improved. If the refractive powers of the two lenses having the features of a cemented lens are the same, the aberration improvement is limited.

[0305] The sixth lens (206) and the seventh lens (207) may be made of the same material. The sixth lens (206) and the seventh lens (207) may be made of plastic. The sixth lens (206) and the seventh lens (207) may be made of a material different from that of the cemented lens (245). Although the cemented lens (245) is made of glass to improve spherical aberration, it is not very effective in improving aspherical aberration caused by a plastic lens. Therefore, two additional lenses including the features of the cemented lens (245) and the cemented lens made of different materials may be provided to improve aberrations not improved by the cemented lens (245).

[0306] At least one or both of the thirteenth surface (S13) and the fourteenth surface (S14) of the seventh lens (207) may have a critical point. The thirteenth surface (S13) of the seventh lens (207) may have a first critical point (P1) from the optical axis (OA) to the far end of the effective area. The first critical point (P1) of the thirteenth surface (S13) may be at least 55% of the effective radius from the optical axis (OA), or may be in the range of 55% to 75%, or may be in the range of 60% to 70%. The first critical point of the thirteenth surface (S13) may be located at a distance of at least 2 mm from the optical axis (OA), for example, at a distance in the range of 2.1 mm to 2.5 mm, or at a distance in the range of 2.2 mm to 2.3 mm. As another example, the thirteenth surface (S13) may be set to have no critical point. The thirteenth surface (S13) having such a first critical point (P1) may refract incident light to the center and the periphery, and may improve aberrations. The first critical point (P1) and the second critical point (P2) are points where the sign of the slope value relative to the optical axis (OA) and the direction perpendicular to the optical axis (OA) changes from positive (+) to negative (-) or from negative (-) to positive (+), which may mean a point where the slope value is zero. In addition, the first critical point (P1) and the second critical point (P2) may be points where the slope value of a tangent line passing through the lens surface changes from large to small or from small to large.

[0307] The fourteenth surface (S14) of the seventh lens (207) may have at least one second critical point (P2) extending from the optical axis (OA) to the far end of the effective area. The second critical point (P2) of the fourteenth surface (S14) may be located at a distance of at least 60% of the effective radius (r72) of the optical axis (OA), or in a range of 60% to 80%, or in a range of 65% to 75%. The second critical point (P2) of the fourteenth surface (S14) may be located at a distance exceeding 2.9 mm from the optical axis (OA), for example, in a range of 2.9 mm to 3.9 mm, or in a range of 3.1 mm to 3.7 mm. Therefore, by positioning the second critical point (P2) closer to the edge than the first critical point (P1), the seventh lens (207) can refract incident light to the periphery of the image sensor (300).

[0308] The average effective radius of the thirteenth surface (S13) and the fourteenth surface (S14) of the seventh lens (207) is set to be smaller than Imgh, which is 1 / 2 of the diagonal length of the image sensor (300), so that light can be refracted to the periphery of the image sensor (300) through the fourteenth surface (S14) having the second critical point (P2).

[0309] like Fig.16 and Fig. 20As shown, Sag41 represents the height from the center of the seventh surface (S7) of the fourth lens (204) to the lens surface in a direction (X, Y) orthogonal to the optical axis (OA), and the maximum value of Sag41 can be the height at the edge of the seventh surface (S7).

[0310] Sag42 represents the height from the center of the eighth surface (S8) of the fourth lens (204) to the lens surface in the direction (X, Y) orthogonal to the optical axis (OA), and the maximum value of Sag42 may be the height at the edge of the eighth surface (S8). Sag52 represents the height from the center of the ninth surface (S9) of the fifth lens (205) to the lens surface in the direction (X, Y) orthogonal to the optical axis (OA), and the maximum value of Sag52 may be the height at the edge of the ninth surface (S9).

[0311] Sag61 represents the height from the center of the eleventh surface (S11) of the sixth lens (206) to the lens surface in the direction (X, Y) orthogonal to the optical axis (OA), and the maximum value of Sag61 may be the height at the edge of the eleventh surface (S11). Sag62 is the height from the center of the twelfth surface (S12) of the sixth lens (206) to the lens surface in the direction (X, Y) orthogonal to the optical axis (OA), wherein the maximum Sag value is the height at the edge.

[0312] The maximum Sag value can meet the following conditions

[0313] Can satisfy Max_Sag51 <Max_Sag52<Max_Sag41。

[0314] The difference between Max_Sag52 and Max_Sag61 may be 0.8 or less. By setting the Sag value between these adjacent glass lenses and plastic lenses, the light loss between the glass lenses and the plastic lenses may be reduced.

[0315] exist Fig. 20 In the embodiment of the present invention, if the Sag value is a positive value, the lens surface is located on the sensor side relative to the straight line orthogonal to the optical axis (OA), and if the Sag value is a negative value, the lens surface is located on the object side relative to the straight line orthogonal to the optical axis (OA). In addition, when the object side surface of each lens is compared with the sensor side surface, the object side surface and the sensor side surface of the seventh lens (207) may be the sides where the difference between the maximum Sag value and the minimum Sag value is the smallest. This may be because the distance between the object side surface of the seventh lens (207) and the sensor side is constant, and the average value of the curvature radius may be greater than the average value of the curvature radius of the other lenses.

[0316] like Fig.15 and Fig.16As shown, the center thickness of the first to seventh lenses (201 to 207) is represented by CT1 to CT7, the edge thickness at the distal end of the effective area of ​​each lens is represented by ET1 to ET7, the center gap between two adjacent lenses is represented by CG1 to CG6, and the edge gap between the edges of each lens is represented by EG1 to EG6. Here, the center thickness of the cemented lens (245) is represented by CT45, and the edge thickness is represented by ET45.

[0317] Reference Fig.16 , the back focal length (BFL) is the optical axis distance from the image sensor (300) to the center of the last lens. Fig.15 In the embodiment, TTL is the optical axis distance from the center of the first surface (S1) of the first lens (201) to the top surface of the image sensor (300).

[0318] Fig.17 yes Fig.15 An example of lens data of the optical system of the second exemplary embodiment. Fig.17 As shown, the radius of curvature of the first lens to the seventh lens (201, 202, 203, 204, 205, 206, 207) on the optical axis (OA), the thickness of the lens, the distance between the centers of the lenses, the refractive index on the d-line, the Abbe number and the size of the clear aperture (CA) can be set.

[0319] like Fig.18 As shown, the lens surfaces of the first lens (201), the second lens (202), the sixth lens (206) and the seventh lens (207) in the lens of the lens unit (200) in the second embodiment may include an aspheric surface having a 30th order aspheric coefficient. For example, the first lens (201), the second lens (202), the sixth lens (206) and the seventh lens (207) may include a lens surface having a 30th order aspheric coefficient. As described above, since the aspheric shape of the periphery can vary particularly significantly, the aspheric surface having a 30th order aspheric coefficient (a value other than "0") can provide good correction of optical performance in the peripheral area of ​​the field of view (FOV).

[0320] like Fig.19 As shown, the thickness (T1 to T7) of the first to seventh lenses (201, 202, 203, 204, 205, 206, 207) and the spacing (gap) (G1 to G6) between two adjacent lenses can be set. Fig.19 As shown, for the thickness of each lens in the Y-axis direction (T1 to T7), a gap of every 0.1 mm or 0.2 mm or more can be indicated, and for the spacing between each lens (G1 to G6), a gap of every 0.1 mm or 0.2 mm or more can be indicated.

[0321] Reference Fig.17 and Fig.19 , when comparing the absolute value of the radius of curvature of each lens, the radius of curvature of the twelfth surface (S12) of the sixth lens (206) on the optical axis (OA) may be the largest among the lenses, and the radius of curvature of the tenth surface (S10) of the fifth lens (205) may be the smallest among the lenses. The difference between the maximum radius of curvature and the minimum radius of curvature may be 10 times or more, for example, in the range of 15 times to 38 times.

[0322] When describing the center thickness of the lens along the optical axis, the center thickness (CT4) of the fourth lens (204) is the largest among the lenses, and the center thickness (CT1) of the first lens (201) is the smallest among the lenses. The difference between the maximum center thickness and the minimum center thickness of the lens can be in the range of from 1.5 mm to 2.5 mm or less.

[0323] When describing the center gap (spacing) (CG) between lenses, the center gap (CG6) between the sixth lens (206) and the seventh lens (207) may be the largest, and the center gap between the second lens (202) and the third lens (203) may be the smallest. Here, the minimum center gap does not include the bonding surface of the bonding lens (245). The difference between the maximum center gap and the minimum center gap of the spaced apart lenses may be at least 1.5 mm, for example, in the range of 2 mm to 3.5 mm. In addition, by setting the maximum center gap between the lenses to be less than or equal to 70% of the maximum center thickness, for example, in the range of 30% to 70%, the thickness of the camera module having a plastic lens with a thin thickness may not be increased without increasing the center gap relative to the center thickness of each lens.

[0324] Regarding the effective diameter, the lens with the largest effective diameter may be disposed between the first lens (201) closest to the object and the seventh lens (207) closest to the image sensor (300). The lens with the largest effective diameter may be a lens made of glass. The lens with the largest effective diameter may be disposed between the first lens (201) and the cemented lens (245). The lens with the largest effective diameter may be the third lens (203). Here, the effective diameter is the average value of the effective diameter of the object side surface and the effective diameter of the sensor side surface of each lens. The lens surface with the largest effective diameter may be the sixth surface (S6) of the third lens (203) or the object side surface of the cemented lens (245).

[0325] The lens with the smallest effective diameter may be any one of the plastic lenses, such as the seventh lens (207) adjacent to the image sensor (300). For example, the effective diameter of the seventh lens (207) may be the minimum value within the lens portion (200). The lens surface with the smallest effective diameter may be the thirteenth surface (S13) of the seventh lens (207).

[0326] The effective diameters of the first to fourth lenses (201 to 204) adjacent to the object side may be larger than the effective diameters of the fifth lens (205), the sixth lens (206), and the seventh lens (207) adjacent to the sensor side. The effective diameters of the first to fourth lenses (201 to 204) may be larger than the diagonal length of the image sensor (300). The average effective diameter of the seventh lens (207) may be smaller than the diagonal length of the image sensor (300). Therefore, light incident through a plurality of lenses aligned along the optical axis may be guided to the image sensor (300).

[0327] In terms of refractive index, the refractive index of the fifth lens (205) is the largest among the lenses and may be greater than 1.7, for example, greater than 1.75. Any one or both of the second lens (202) and the sixth lens (206) may have the smallest refractive index among the lenses. For example, the smallest refractive index may be less than 1.6, for example, less than 1.55. The difference between the maximum refractive index and the minimum refractive index may be greater than or equal to 0.2. By setting one of the lenses adjacent to the sensor as a high refractive index lens made of glass, and setting the lens adjacent to the glass lens and the lens adjacent to the image sensor (300) as low refractive index lenses made of plastic, the incident efficiency may be improved, and the refractive power between the glass lens and the plastic lens may be adjusted to guide light to the image sensor (300).

[0328] When comparing Abbe numbers, the Abbe number of the third lens (203) is the largest among the lenses and may be greater than 60. The first lens (201) and the seventh lens (207) have the lowest Abbe number among the lenses, and the lowest Abbe number may be 25 or less. The difference between the maximum refractive index and the minimum Abbe number may be 40 or more. By setting the maximum Abbe number for the third lens (203) adjacent to the cemented lens (245), and setting the minimum Abbe number for the first lens (201) closest to the object side and the low refractive index seventh lens (207) adjacent to the image sensor (300), the dispersion of light passing between the glass lenses can be controlled, and the light can be guided to the image sensor (300) by increasing the dispersion between the glass lens and the plastic lens.

[0329] The focal lengths (F1, F5, F7) of the first lens (201), the fifth lens (205) and the seventh lens (207) may have a negative (-) sign. The first lens (201), the fifth lens (205) and the seventh lens (207) may have a negative (-) refractive power. The focal lengths (F2, F3, F4, F6) of the second lens (202), the third lens (203), the fourth lens (204) and the sixth lens (206) may have a positive (+) sign. The second lens (202), the third lens (203), the fourth lens (204) and the sixth lens (206) may have a positive (+) refractive power. On the sensor side of the first lens (201) having a negative (-) refractive power, the second lens (202), the third lens (203) and the fourth lens (204) having a positive (+) refractive power may be provided. Thereby, light incident from the object side can be deviated from the optical axis direction and collected again toward the optical axis direction, thereby forming a stable light path.

[0330] In addition, adjacent lenses, namely, the sixth lens (206) and the seventh lens (207), may satisfy the following conditions.

[0331] Condition 1: The refractive index of the lens with positive refractive power < the refractive index of the lens with negative refractive power

[0332] Condition 2: The change range of the lens with positive refractive power > the change range of the lens with negative refractive power

[0333] Here, among the plastic lenses, the sixth lens (206) has a positive refractive power, and the seventh lens (207) has a negative refractive power, so that according to conditions 1 and 2, the refractive index of the sixth lens is smaller than the refractive index of the seventh lens, and the variation amplitude of the sixth lens is larger than the variation amplitude of the seventh lens. The chromatic aberration generated by the plastic lens can be corrected by the plastic lens. In addition, the chromatic aberration generated by the plastic lens can be compensated by the plastic lens by satisfying the following: the refractive index difference between the sixth lens (206) and the seventh lens (207) as plastic lenses arranged continuously is greater than 0.1 and less than 0.15, and the Abbe number difference is greater than 20 and less than 60.

[0334] The optical system is affected by chromatic aberration, which is compensated by using a cemented lens or two lenses placed back to back. As the temperature changes from low to high, the lenses shrink and expand. Since lenses of the same material have the same amount of change in lens properties as the temperature changes, it is effective to correct chromatic aberration between lenses of the same material even when the temperature changes.

[0335] Therefore, in the second embodiment of the present invention, the fourth lens (204) and the fifth lens (205) are used to correct the chromatic aberration of lenses made of glass, and the sixth lens (206) and the seventh lens (207) are used to correct the chromatic aberration of plastic lenses.

[0336] Chromatic aberration caused by a glass lens can be compensated by the glass lens by satisfying that the refractive index difference of the fourth lens (204) and the fifth lens (205) as the lenses to be cemented is at least 0.1 but not more than 0.15 and the Abbe number is at least 20 but not more than 60. The refractive index difference is rounded to three decimal places and the Abbe number difference is rounded to one decimal place to compare these values.

[0337] Furthermore, by placing a glass lens having a relatively high Abbe number on the object side of the plastic lens, dispersion can be reduced by the glass lens and increased by the plastic lens.

[0338] When the focal lengths are compared in absolute values, the focal length of the second lens (202) is the largest among the lenses, and may be greater than 55 or greater than 100. Among the lenses, the second lens (202) made of plastic may have the largest focal length and the smallest refractive power. The focal lengths of the first lens (201), the second lens (202), the sixth lens (206), and the seventh lens (207) made of plastic may be greater than the focal lengths of the third lens (203), the fourth lens (204), and the fifth lens (205) made of glass. The focal length of the fifth lens (205) may be the smallest among the lenses, for example, 15 or less, or 10 or less. Among the lenses, the fifth lens (205) made of glass may have the smallest focal length and the largest refractive power. On the sensor side of the fifth lens (205), a lens made of a plastic material having a small refractive power may be provided so that the refractive power of the fifth lens (205) may be large.

[0339] Among the lenses other than the cemented lens (245), the lens having the minimum focal length may be the third lens (203). The difference between the maximum focal length and the minimum focal length may be 50 or more, or may be 80 or more. Therefore, the optical system may have improved MTF characteristics, aberration control characteristics, resolution characteristics, etc. within a set field of view, and may have good optical performance at the periphery of the field of view.

[0340] There is a critical point on the sensor side surface of the seventh lens (207). The critical point is a point where the trend of the sag value changes, that is, the critical point is a point where the sag value increases and then decreases, or a point where the sag value decreases and then increases.

[0341] Reference Fig. 20, it can be seen that there is a critical point between points spaced 1.9 mm apart and points spaced 2.1 mm apart on the object side of the seventh lens (207) in the direction perpendicular to the optical axis. The object side surface of the seventh lens (207) shows that the sag value increases to points spaced 2.0 mm apart in the direction perpendicular to the optical axis, and then the sag value decreases from the points spaced 2.0 mm apart in the direction perpendicular to the optical axis to the points spaced 4.2 mm apart in the direction perpendicular to the optical axis.

[0342] The sensor side surface of the seventh lens (207) shows that there is a critical point between a point 3.3 mm apart in the direction perpendicular to the optical axis and a point 3.5 mm apart in the direction perpendicular to the optical axis. On the sensor side surface of the seventh lens (207), the sag value increases to a point 3.4 mm apart in the direction perpendicular to the optical axis, and then the sag value decreases from a point 3.4 mm apart in the direction perpendicular to the optical axis to a point 4.6 mm apart in the direction perpendicular to the optical axis. The presence of the critical point on the sensor side surface of the seventh lens (207) (i.e., the sensor side surface of the last lens, i.e., the lens surface closest to the sensor) enables TTL to be reduced, thereby facilitating miniaturization and lightweighting of the optical system.

[0343] The thickness (T1) of the first lens (201) may be in the range of 1 to 1.1 times, for example, the difference between the maximum thickness and the minimum thickness exceeds 1 times, wherein the center thickness (CT1) is the maximum and the edge thickness (ET1) is the minimum. The thickness (T2) of the second lens (202) may be in the range of 1 to 1.2 times the maximum thickness of the minimum thickness. The second lens (202) may have a maximum center thickness (CT2) and a minimum edge thickness (ET2). The third lens (203) may have a thickness (T3) that is maximum at the center and minimum at the edge, wherein the maximum thickness is in the range of 1.5 to 2 times the minimum thickness. The thickness (T4) of the fourth lens (204) may be maximum at the center and minimum at the edge, wherein the maximum thickness is in the range of 1.9 to 2.2 times the minimum thickness. The thickness (T5) of the fifth lens (205) may be minimum at the center and maximum at the edge, wherein the maximum thickness is in the range of 1.7 to 1.9 times the minimum thickness. The thickness (T6) of the sixth lens (206) may be maximum at the center and minimum at the edge, wherein the maximum thickness is in the range of 1.4 to 1.6 times the minimum thickness. The thickness (T7) of the seventh lens (207) may be minimum at the center and maximum at the edge, wherein the maximum thickness is in the range of 1 to 1.2 times the minimum thickness.

[0344] The center thickness (CT45) of the cemented lens (245) may be greater than the edge thickness (ET45). The center thickness (CT45) of the cemented lens (245) is the distance from the center of the seventh surface (S7) on the object side of the fourth lens (204) to the center of the tenth surface (S10) of the fifth lens (205), and the edge thickness (ET45) is the distance from the far end of the effective area of ​​the seventh surface (S7) to the tenth surface (S10) in the optical axis direction. The maximum thickness of the cemented lens (245) is at the center, the minimum thickness is at the edge, and the maximum thickness may be in the range of 1 to 1.2 times the minimum thickness.

[0345] Among the gaps (G1 to G6) between the lenses, the first gap (G1) between the first lens (201) and the second lens (202) may be maximum at the center and minimum at the edge. The second gap (G2) between the second lens (202) and the third lens (203) may have a maximum value at the edge and a minimum value at the center. The third gap (G3) between the third lens (203) and the fourth lens (204) may be maximum at the edge and minimum at the center. The fifth gap (G5) between the fifth lens (205) and the sixth lens (206) may be maximum at the center and minimum at the edge. The sixth gap (G6) between the sixth lens (206) and the seventh lens (207) may have a maximum value at the center and a minimum value at the edge.

[0346] like Fig.21 As shown, in Fig.15 In the optical system and the camera module, the chief ray angle (CRA) may be within a range of 10 degrees or more, for example, within a range of 10 degrees to 35 degrees, or within a range of 10 degrees to 25 degrees, at a distance of 10 degrees from the far end of the diagonal length of the image sensor. In addition, the difference in the chief ray angle from a low temperature (-40 degrees Celsius) to a high temperature (95 degrees Celsius) may be 1 degree or less. Therefore, even if the temperature changes from a low temperature to a high temperature, the angle difference of the chief ray angle is not large, and stable optical performance can be achieved.

[0347] In the optical system according to the second embodiment, as Fig.28 As shown, a graph of the ambient illumination ratio or relative illumination according to the image height is illustrated, and it can be seen that the ambient illumination ratio is 70% or more, for example, 75% or more, from the center of the image sensor to the far end of the diagonal line. In other words, it can be seen that the difference between the ambient illumination (zoom positions 1, 2, 3) according to the temperature at normal temperature, low temperature, and high temperature is almost the same at a distance of 4.5 mm or more from the optical axis.

[0348] Figure 22 to Figure 24 yes Fig.15A graph of the modulation transfer function (MTF) of diffraction in an optical system at room temperature, low temperature, and high temperature, which plots the brightness ratio (modulation) as a function of spatial frequency. Figure 22 to Figure 24 As shown, in an exemplary embodiment of the present invention, the deviation of MTF from room temperature to low temperature or high temperature may be less than 10%, such as 7% or less.

[0349] Figure 25 to Figure 27 It is a description of Fig.15 The aberration characteristics of the optical system at room temperature, low temperature and high temperature. Figure 25 to Figure 27 In the aberration graph of , longitudinal spherical aberration, astigmatism field curve, and distortion are measured from left to right. Figure 25 to Figure 27 In the graph, the X-axis may represent focal length (mm) or distortion (%), and the Y-axis may represent the height of the image. In addition, the graph of spherical aberration is a graph of light in wavelength bands of about 435 nm, about 486 nm, about 546 nm, about 587 nm, and about 656 nm, and the graph of astigmatism and distortion aberration is a graph of light in a wavelength band of about 546 nm. Figure 25 to Figure 27 In the aberration diagram, it can be interpreted that the closer each curve is to the Y-axis at room temperature, low temperature, and high temperature, the better the aberration correction function is, and it can be seen that the optical system (2000) according to the embodiment has measurement values ​​close to the Y-axis in almost all areas, which means that the optical system (2000) according to the embodiment has improved resolution and can have good optical performance not only in the center of the field of view (FOV) but also in the periphery. Here, the low temperature can be below -20 degrees Celsius, for example, in the range of -20 degrees Celsius to -40 degrees Celsius, the room temperature can be in the range of 22 degrees Celsius ±5 degrees Celsius or in the range of 18 degrees Celsius to 27 degrees Celsius, and the high temperature can be above 85 degrees Celsius, for example, in the range of 85 degrees Celsius to 205 degrees Celsius. Therefore, it can be seen Figure 25 to Figure 27 The decrease in brightness ratio modulation from low temperature to high temperature is less than 10%, such as 5% or less, or almost no change.

[0350] Table 2 compares the changes in optical properties such as EFL, BFL, F number (F#), TTL and field of view (FOV) at room temperature, low temperature and high temperature in the optical system according to the exemplary second embodiment, and it can be seen that the rate of change of the optical properties at low temperature relative to room temperature is 5% or less, for example 3% or less, and the rate of change of the optical properties at high temperature relative to room temperature is 5% or less, for example 3% or less.

[0351] [Table 2]

[0352] Room temperature Low temperature high temperature Low temperature / room temperature High temperature / room temperature EFL(F) 15.1000 15.0319 15.1820 99.54％ 100.44％ BFL 2.5000 2.4971 2.5035 99.87％ 100.14％ F# 1.6000 1.5938 1.6076 99.61％ 100.47％ TTL 33.2904 33.2217 33.3712 99.79％ 100.24％ FOV 34.0400 34.1857 33.8684 100.42％ 99.49％

[0353] Therefore, as shown in Table 2, it can be seen that the change in optical properties such as effective focal length (EFL), TTL, BFL, F number and field of view (FOV) due to the change in temperature from low temperature to high temperature is within the range of 0 to 5%, for example, 5% or less. This makes it possible to design the plastic lens for temperature compensation to prevent the reduction in reliability of the optical properties even in the case of using at least one or more sheets (layers) of plastic lenses.

[0354] The optical system of the second embodiment disclosed above can effectively control aberration characteristics such as chromatic aberration and distortion aberration, and can have good optical performance not only in the center of the field of view (FOV) but also in the periphery.

[0355] The optical system (1000, 2000) according to the first embodiment and the second embodiment disclosed above can satisfy at least one or two of the mathematical expressions described below. Therefore, the optical system (1000, 2000) according to the embodiment can have improved optical properties. For example, when the optical system (1000, 2000) satisfies at least one of the mathematical expressions, the optical system (1000, 2000) can effectively control aberration characteristics such as chromatic aberration, distortion aberration, etc., and can have good optical performance at the center and periphery of the field of view (FOV). In addition, the optical system (1000, 2000) can have improved resolution. In addition, the thickness of the lens at the optical axis (OA) described in the mathematical expression and the gap (spacing) of the adjacent lens at the optical axis (OA) can be understood with reference to the first embodiment and the second embodiment disclosed above.

[0356] [Mathematical expression 1]

[0357] 0.5 <CT1 / ET1<1.5

[0358] In Mathematical Expression 1, CT1 is the center thickness of the first lens (101, 201), and ET1 is the edge thickness of the first lens (101, 201). Therefore, a factor affecting the field of view of the optical system can be set, and a factor affecting the effective focal length (EFL) can be set, preferably satisfying 0.6≤CT1 / ET1<1 in the first embodiment, and preferably satisfying 0.6≤CT1 / ET1<1.2 in the second embodiment.

[0359] [Mathematical expression 2]

[0360] 0.1 <CT1 / CA_L1S1<0.5

[0361] In Mathematical Expression 2, CT1 is the center thickness of the first lens (101, 201), and CA_L1S1 is the effective diameter of the object side surface (S1) of the first lens (101, 201). If Mathematical Expression 2 is satisfied, the strength and optical properties of the injection molded lens made of glass can be prevented from being reduced. If it is below the range of Mathematical Expression 2, the lens may be broken or difficult to injection mold, and if it is above the range, the TTL may increase and the weight of the optical system may become heavy. Preferably, in the first embodiment and the second embodiment, 0.12 may be satisfied. <CT1 / CA_L1S1<0.2。

[0362] [Mathematical expression 3]

[0363] Po1<0

[0364] In Mathematical Expression 3, Po1 is the sign of the refractive power of the first lens (101, 201). For the performance of the optical system, Pol can be set to have a short effective focal length relative to TTL in the optical system. If Mathematical Expression 3 is satisfied, light incident on the first lens (101, 201) from the object side can be diffused in a direction away from the optical axis. The entire optical system can have a stable structure for diffusing and collecting light.

[0365] [Mathematical expression 3-1]

[0366] F6*F7<0

[0367] In Mathematical Expression 3-1, F6 is the focal length of the sixth lens (106, 206), and F7 is the focal length of the seventh lens (107, 207). The condition in Mathematical Expression 3-1 enables the product of the focal lengths of the plastic lenses to be arranged in a mixed manner of negative (-) refractive power and positive (+) refractive power so that they compensate each other. This enables the aberrations generated by the plastic lenses to be offset.

[0368] [Mathematical expression 4]

[0369] 1.6 <n1<2.2

[0370] In Mathematical Expression 4, n1 is the refractive index at the d-line of the first lens (101, 201). Mathematical Expression 4 sets the refractive index of the first lens to be high, which can control the factors that affect the reduction of the third-order aberration (Seidel aberration) of the optical system and can reduce the aberration that may be caused by a slightly longer TTL. Mathematical Expression 4 can preferably satisfy 1.75 < n1 < 2.1 in the first embodiment, and can preferably satisfy 1.65 < n1 < 1.8 in the second embodiment. If the design is below the lower limit of Mathematical Expression 4, it may be ineffective in reducing aberration, and the first lenses 101, 201 may have reduced power and be unable to collect light efficiently, resulting in poor optical system performance. If the design is above the upper limit of Mathematical Expression 4, it may be difficult to obtain the material. In addition, if the refractive index of the first lens (101, 201) is designed to be below the lower limit of Mathematical Expression 4, the radius of curvature of the first lens (101) and the second lens (102) must be increased to increase the refractive power of the first lens (101) and the second lens (102), which may make lens manufacturing more difficult, increase the lens defect rate, and reduce the yield.

[0371] [Mathematical Expression 4-1]

[0372] 1.6 ≤ Aver(n1:n7) ≤ 1.7

[0373] In Mathematical Expression 4-1, Aver(n1:n7) is the average value of the refractive index values at the d-line of the first lens to the seventh lens (101 to 107). If the optical system (1000, 2000) according to the embodiment satisfies Mathematical Expression 4-1, the optical system (1000, 2000) can set the resolution and suppress the influence on the TTL.

[0374] [Mathematical Expression 5]

[0375] 27 < FOV_H < 33

[0376] In Mathematical Expression 5, FOV_H represents the horizontal field of view, which can set the range of the automotive optical system. In the first embodiment and the second embodiment, Mathematical Expression 5 can preferably satisfy 28 ≤ FOV_H ≤ 31, or can satisfy a range of 29.9 degrees ± 3 degrees, where the sensor length in the horizontal direction is based on 8.064 mm ± 0.5 mm. In addition, if Mathematical Expression 5 is satisfied, the change rate of the effective focal length and the change rate of the field of view when the temperature changes from normal temperature to high temperature can be set to 5% or less, for example, 0 to 5%. In addition, even in the case where two or more, for example, three or more plastic lenses are mixed in the optical system (1000, 2000), the temperature compensation of the plastic lenses can prevent the degradation of optical properties.

[0377] [Mathematical expression 6]

[0378] L3R1>0

[0379] L3R2<0

[0380] |L3R1|>|L3R2|

[0381] In Mathematical Expression 6, L3R1 is the curvature radius of the object side surface of the third lens (103, 203), and L3R2 is the curvature radius of the sensor side surface of the third lens (103, 203). The third lens (103, 203) may have a convex shape on both surfaces. Since the third lens (103, 203) has a convex shape on both surfaces, light can be refracted so that the effective diameters of the fourth to seventh lenses (104 to 107, 204 to 207) disposed on the sensor side surface of the third lens (103, 203) do not become larger, and the number of lenses can be reduced. In addition, since the condition of |L3R1|>|L3R2| is obtained, light can be adjusted so that the effective diameters of the sensor side lenses of the third lens (103, 203), that is, the fourth to seventh lenses (104 to 107, 204 to 207) do not become larger, and TTL can be reduced. If the condition of |L3R1|<|L3R2| exists, there is a problem that the object side surface of the third lens (103, 203) has a large amount of aberration and the sensor side surface of the third lens (103, 203) cannot refract light well, resulting in an increase in the effective diameter or an increase in TTL.

[0382] [Mathematical expression 7]

[0383] 1 <L7S2_max_sag to Sensor<3

[0384] In Mathematical Expression 7, L7S2_max_sag to Sensor refers to the straight-line distance from the maximum Sag value of the seventh lens (107, 207) to the image sensor (300). If this mathematical expression is satisfied, the TTL can be reduced, and the conditions for constructing the imaging device module can be set. In addition, L7S2_max_sag to Sensor can set the space for placing the filter (500) and cover glass (400) located between the image sensor (300) and the seventh lens (107, 207). If the range of Mathematical Expression 7 is less than the lower limit, the space for placing circuit structures such as filters and image sensors may be restricted, and the process of assembling circuit structures such as filters and image sensors into the optical system may become difficult. If the range of Mathematical Expression 7 is greater than the upper limit, the process of assembling circuit structures such as filters and image sensors into the optical system is easier, but the TTL becomes longer, making it difficult to miniaturize the optical system.

[0385] In other words, Mathematical Expression 7 can set the minimum distance between the image sensor (300) and the last lens, preferably satisfying 1 < L7S2_max_sag to Sensor ≤ BFL. In addition, if the last lens does not have a point (P2) that protrudes more toward the image sensor than the center of the sensor side surface, the value of Mathematical Expression 7 may be equal to the back focal length (BFL). BFL is the optical axis distance from the image sensor (300) to the center of the sensor side surface of the last lens. Specifically, it is preferable to satisfy 1.5 < L7S2_max_sag to Sensor < 2.0 for ease of manufacturing and TTL reduction.

[0386] [Mathematical Expression 8]

[0387] 1 < CT1 / CT7 < 3

[0388] In Mathematical Expression 8, CT1 is the center thickness of the first lens (101, 201), and CT7 is the center thickness of the seventh lens (107, 207). If Mathematical Expression 8 is satisfied, the aberration characteristics can be improved, and the influence on the contraction of the optical system can be established. Mathematical Expression 8 can preferably satisfy 1 < CT1 / CT7 < 2 in the first embodiment and 1 < CT1 / CT7 < 1.8 in the second embodiment. Mathematical Expression 8 can set the object-side lens and sensor-side lens of the optical system to be made of glass and plastic lens, respectively, and can limit the difference between their center thicknesses. Therefore, the chromatic aberration of the optical system can be improved, and the total track length (TTL) can be controlled to have good optical performance at the set field of view.

[0389] [Mathematical Expression 9]

[0390] 1 < CT45 / CT6 < 5

[0391] In Mathematical Expression 9, CT45 is the center thickness of the fourth lens (104) and the fifth lens (105), such as the center thickness of the cemented lens (145), and CT6 is the center thickness of the sixth lens (106, 206). If the optical system satisfies Mathematical Expression 9, the thicknesses of the cemented lens and the adjacent sixth lens (106, 206) can be set to improve the aberration characteristics, and preferably 1 < CT45 / CT6 < 3 or 1.5 < CT45 / CT6 < 2.5 is satisfied in the first embodiment and the second embodiment. CT45 can be greater than the center thickness (CT1 to CT7) of each of the first lens to the seventh lens. Here, the condition CT45 > ET45 can be satisfied.

[0392] [Mathematical Expression 10]

[0393] 0.2 < CT45 - ET45 < 0.5

[0394] In Mathematical Expression 10, CT45 is the center thickness of the fourth lens and the fifth lens (104 to 105, 204 to 205), such as the center thickness of the cemented lens (145, 245), and ET45 is the optical axis distance from the distal end of the effective region on the object side surface of the fourth lens (104, 204) to the distal end of the effective region on the sensor side surface of the fifth lens (105, 205). If the optical system satisfies Mathematical Expression 10, the center thickness and the edge thickness of the cemented lens can be set to improve the aberration characteristics, and preferably 0.3 ≤ CT45 / ET45 < 0.5 is satisfied in the first embodiment and the second embodiment. ET45 can be greater than the edge thickness (ET1 to ET7) of each of the first lens to the seventh lens.

[0395] [Mathematical Expression 11]

[0396] 0 < CA_L1S1 / CA_L4S1 < 2

[0397] In Mathematical Expression 11, CA_L1S1 means the effective diameter of the first surface (S1) of the first lens (101, 201), and CA_L4S1 means the effective diameter of the seventh surface (S7) of the fourth lens (104, 204). If Mathematical Expression 11 is satisfied, the optical system (1000, 2000) can control the incident light, and the factors affecting the aberration can be set, and preferably 0.5 < CA_L1S1 / CA_L4S1 < 1 is satisfied in the first embodiment and the second embodiment.

[0398] [Mathematical Expression 12]

[0399] 0 <CA_L7S2 / CA_L5S2<2

[0400] In mathematical expression 12, CA_L5S2 refers to the effective diameter of the tenth surface (S10) of the fifth lens (105, 205), and CA_L7S2 refers to the effective diameter of the fourteenth surface (S14) of the seventh lens (107, 207). If mathematical expression 12 is satisfied, the optical system (1000, 2000) can control the incident light path, and can set the factor of CRA and temperature-related performance variation. Preferably, in the first embodiment and the second embodiment, mathematical expression 12 can satisfy 0.5 <CA_L7S2 / CA_L5S2<1。

[0401] [Mathematical expression 13]

[0402] 0 <CA_L1S2 / CA_L2S1<2

[0403] In Mathematical Expression 13, CA_L1S2 refers to the effective diameter of the second surface (S2) of the first lens (101, 201), and CA_L2S1 refers to the effective diameter of the third surface (S3) of the second lens (102, 202). If Mathematical Expression 13 is satisfied, the optical system (1000, 2000) can control the light traveling to the first lens group (LG1) and the second lens group (LG2), and a factor affecting the reduction of the lens sensitivity can be set. Mathematical Expression 15 can preferably satisfy 0.5 in the first embodiment and the second embodiment. <CA_L1S2 / CA_L2S1<1.5。

[0404] [Mathematical expression 14]

[0405] 0.5 <CA_L4S1 / CA_L5S2<2.5

[0406] In Mathematical Expression 14, CA_L4S1 refers to the effective diameter of the seventh surface (S7) of the fourth lens (104, 204), and CA_L5S2 refers to the effective diameter of the tenth surface (S10) of the fifth lens (105, 205). If the optical system (1000, 2000) satisfies Mathematical Expression 14, the size of the cemented lens disposed on the object side of the plastic lens can be set. Mathematical Expression 14 can preferably satisfy 0.8≤CA_L4S1 / CA_L5S2<1.5 in the first embodiment, and preferably satisfy 1≤CA_L4S1 / CA_L5S2<1.5 in the second embodiment.

[0407] [Mathematical expression 15]

[0408] 2 < L3R1 / (CA_L3S1 / 2) < 5

[0409] In Mathematical Expression 15, L3R1 is the radius of curvature of the object-side surface of the third lens (103, 203), and CA_L3S1 is the effective diameter of the fifth surface (S5) on the object side of the third lens (103, 203). If the third lens (103, 203) convex on both surfaces satisfies Mathematical Expression 15, the optical system (1000, 2000) can improve chromatic aberration. If the lower limit value of Mathematical Expression 15 is less than the upper limit value, the aberration caused by the fifth surface (S5) will increase, and if the upper limit value is greater than the lower limit value, the aberration caused by the fifth surface (S5) will decrease, but the radius of curvature of the sixth surface (S6) will need to be smaller, which will increase the aberration caused by the sixth surface (S6) and affect the aberration of the fourth lens to the seventh lens (104 to 107, 204 to 207). In the first embodiment, if the range of 4 < L3R1 / (CA_L3S1 / 2) < 5 is preferably satisfied, and in the second embodiment, if the range of 3 < L3R1 / (CA_L3S1 / 2) < 4 is preferably satisfied, the radius of curvature of the sixth surface (S6) can be designed to be large while reducing the aberration generated on the fifth surface (S5), thereby facilitating the manufacture of the third lens (103, 203). By reducing the aberration in the optical system and making it easier to manufacture the third lens (103, 203), the production yield can be increased.

[0410] [Mathematical Expression 15-1] CA_L4 > CA_L5 > CA_L6 > CA_L7

[0411] [Mathematical Expression 15-2] CA_L7S1 < (Imgh * 2)

[0412] In Mathematical Expressions 15-1 to 15-2, CA_L4, CA_L5, CA_L6, CA_L7 are the effective diameters (average effective diameters) of the fourth lens to the seventh lens (104 to 107, 204 to 207), and Imgh is 1 / 2 of the diagonal length of the image sensor (300). Therefore, the optical path from the fourth lens (104, 204) to the seventh lens (107, 207) can be guided to the area of the image sensor (300) through the effective diameters of the fourth lens (104, 204) to the seventh lens (107, 207). Since the sixth lens and the seventh lens (106 to 107, 206 to 207) are plastic lenses with aspherical surfaces, and the fourth lens (104) and the fifth lens (105) are glass lenses with spherical surfaces, the aberration between the lenses can be compensated for each other.

[0413] [Mathematical Expression 16]

[0414] 1 <CA_GL_AVER / CA_PL_AVER<1.5

[0415] In Mathematical Expression 16, CA_GL_AVER is the average effective diameter of the glass lens, and CA_PL_AVER is the average effective diameter of the plastic lens. By setting the effective diameter size of the glass lens and the effective diameter size of the plastic lens in Mathematical Expression 16, the path of the incident light can be effectively guided. Mathematical Expression 16 can preferably satisfy 1.1 in the first embodiment and the second embodiment. <CA_GL_AVER / CA_PL_AVER<1.3。

[0416] Here, nGL>nPL may be satisfied, where nGL is the number of glass lenses, and nPL is the number of plastic lenses. It may also satisfy the condition nGL-nPL=0 or 1.

[0417] [Mathematical expression 17]

[0418] 1.2≤GL_CA1_AVER / PL_CA1_AVER≤1.5

[0419] In Mathematical Expression 17, GL_CA1_AVER is an average value of effective diameters of object-side surfaces of glass lenses, for example, an average value of effective diameters of object-side surfaces of the first lens, the third lens, the fourth lens, and the fifth lens ((101, 103, 104, 105), (201, 203, 204, 205)). PL_CA1_AVER is an average value of effective diameters of object-side surfaces of plastic lenses, for example, an average value of effective diameters of object-side surfaces of the second lens, the sixth lens, and the seventh lens ((102, 106, 107), (202, 206, 207)). Since the effective diameter size of the plastic lens is relatively small compared to the glass lens, Mathematical Expression 17 may be satisfied. Mathematical Expression 17 may preferably satisfy 1.3≤GL_CA1_AVER / PL_CA1_AVER≤1.4 in the first embodiment, and preferably satisfy 1.2≤GL_CA1_AVER / PL_CA1_AVER≤1.4 in the second embodiment.

[0420] [Mathematical expression 18]

[0421] CG3 <CG5<CG1

[0422] In mathematical expression 18, CG1 can be the central gap (spacing) between the first lens and the second lens (101 to 102, 201 to 202), CG3 can be the central spacing between the third lens and the fourth lens (103 to 104, 203 to 204), and CG5 can be the central spacing between the fifth lens and the sixth lens (105 to 106, 205 to 206). If mathematical expression 18 is satisfied, the central spacing between relatively thick glass lenses can be reduced, which can reduce the TTL and improve the optical performance of the peripheral part of the field of view (FOV).

[0423] [Mathematical expression 19]

[0424] 1 < CT7 / CG6 < 3

[0425] In mathematical expression 19, CG6 is the central spacing or the optical axis distance between the sixth lens and the seventh lens (106 to 107, 206 to 207). In mathematical expression 19, the central thickness (CT7) of the seventh lens (107, 207) and the central spacing between the sixth lens (6) and the seventh lens (7) can be set to improve the optical performance at the periphery of the field of view. Mathematical expression 19 can preferably satisfy 1.1 < CT7 / CG6 < 1.5 in the first embodiment and preferably satisfy 1.5 < CT7 / CG6 < 2 in the second embodiment.

[0426] [Mathematical expression 20]

[0427] 1 < CT2 / CT1 < 2 (first exemplary embodiment)

[0428] 1 < CT1 / CT2 < 2 (second exemplary embodiment)

[0429] In mathematical expression 20, CT1 is the central thickness of the first lens (101, 201), and CT2 is the central thickness of the second lens (102, 202). By setting the central thickness CT2 of the second lens to be greater than the central thickness CT1 of the first lens in mathematical expression 20, the factors affecting aberration can be controlled. In the first embodiment, mathematical expression 20 can preferably satisfy 1.1 < CT2 / CT1 < 2, and in the second embodiment, mathematical expression 20 can preferably satisfy 1.1 < CT1 / CT2 < 2.

[0430] [Mathematical expression 21]

[0431] 1 < L7R1 / CT7 < 20

[0432] In Mathematical Expression 21, L7R1 is the radius of curvature of the thirteenth surface (S13) of the seventh lens (107, 207), and CT7 is the center thickness of the seventh lens (107, 207). By setting the radius of curvature L7R1 of the object-side surface of the seventh lens (107, 207) and the center thickness of the seventh lens (107, 207) in Mathematical Expression 21, the refractive power of the seventh lens (107, 207) can be controlled. Therefore, good optical performance can be achieved at the center and periphery of the field of view. Preferably in the first and second embodiments, Mathematical Expression 21 can satisfy 1 < L7R1 / CT7 < 16.

[0433] [Mathematical Expression 22]

[0434] 0 < CT_Max / CG_Max < 3

[0435] In Mathematical Expression 22, CT_Max is the maximum center thickness of the lens, and CG_Max is the maximum distance between adjacent lenses. If Mathematical Expression 22 is satisfied, the optical system can have good optical performance at the set field of view at the focal length, and the TTL can be reduced. In the first embodiment, Mathematical Expression 22 can preferably satisfy 1 < CT_Max / CG_Max < 1.5, while in the second embodiment, Mathematical Expression 22 can preferably satisfy 2 < CT_Max / CG_Max < 3.

[0436] [Mathematical Expression 23]

[0437] 2 < ΣCT / ΣCG < 3

[0438] In Mathematical Expression 23, ΣCT is the sum of the center thicknesses of the lenses, and ΣCG is the sum of the distances between adjacent lenses. If Mathematical Expression 23 is satisfied, the optical system can have good optical performance at the given field of view at the focal length, and the TTL can be reduced. In the first and second embodiments, Mathematical Expression 23 can preferably satisfy 2 < ΣCT / ΣCG < 2.9.

[0439] [Mathematical Expression 24]

[0440] 10 < ΣIndex < 20

[0441] In Mathematical Expression 24, ΣIndex is the sum of the refractive index at the d-line of each of the plurality of lenses. If Mathematical Expression 24 is satisfied, TTL can be controlled in an optical system (1000, 2000) including a mixture of plastic lenses and glass lenses, and resolution can be improved. In addition, in the case where the number of glass lenses is greater than the number of plastic lenses, when the number of glass lenses having a relatively large thickness is greater than the number of plastic lenses, TTL and the sum of the refractive index can be set. In the first embodiment and the second embodiment, Mathematical Expression 24 can preferably satisfy 10<ΣIndex<15.

[0442] [Mathematical expression 25]

[0443] 10<ΣAbb / ΣIndex<35

[0444] In mathematical expression 25, ΣAbb means the sum of the Abbe numbers of each of the plurality of lenses. If mathematical expression 25 is satisfied, the optical system (1000, 2000) can have improved aberration characteristics and resolution. By setting mathematical expression 25 to the sum of the Abbe number and the refractive index of the lens, the optical properties can be controlled, and in the first embodiment, mathematical expression 24 can preferably satisfy 10<ΣAbb / ΣIndex<30, and in the second embodiment, mathematical expression 24 can preferably satisfy 10<ΣIndex<15.

[0445] [Mathematical expression 26]

[0446] 1<ΣCT / ΣET<2

[0447] In Mathematical Expression 26, ΣCT is the sum of the center thickness of the lens, and ΣET is the sum of the end, i.e., edge thickness of the effective area of ​​the lens. If Mathematical Expression 26 is satisfied, the optical system can have good optical performance at a set field of view at a focal length, and TTL can be reduced. In the first and second embodiments, Mathematical Expression 26 can preferably satisfy 1<ΣCT / ΣET<1.5.

[0448] [Mathematical expression 27]

[0449] 0.5 <CA_L3S1 / CA_min<5

[0450] In Mathematical Expression 27, CA_L3S1 is the effective diameter of the object-side fifth surface (S5) of the third lens (103, 203), and CA_min is the minimum effective diameter of the object-side surface and the sensor-side surface of the lens. By satisfying Mathematical Expression 27, the optical system can control incident light, maintain optical performance, and provide a thinner module. In the first and second embodiments, Mathematical Expression 27 can preferably satisfy 1 <CA_L3S1 / CA_min<2。

[0451] [Mathematical expression 28]

[0452] 1 <CA_max / CA_min<3

[0453] In Mathematical Expression 28, CA_max represents the maximum effective diameter between the object side surface and the sensor side surface of the lens, and CA_min represents the minimum effective diameter between the object side surface and the sensor side surface of the lens. If Mathematical Expression 28 is satisfied, the optical system can be sized to obtain a slim and compact structure while maintaining optical performance. In the first and second embodiments, Mathematical Expression 28 may preferably satisfy 1 <CA_max / CA_min<2。

[0454] [Mathematical expression 29]

[0455] 1 <CA_max / CA_Aver<3

[0456] In Mathematical Expression 29, CA_max represents the maximum effective diameter of the object side surface and the sensor side surface of the lens, and CA_Aver represents the average value of the effective diameters of the object side surface and the sensor side surface of the lens. If Mathematical Expression 29 is satisfied, the optical system can be sized to obtain a slim and compact structure while maintaining optical performance. In the first and second embodiments, Mathematical Expression 29 may preferably satisfy 1 <CA_max / CA_Aver<1.5。

[0457] [Mathematical expression 30]

[0458] 0.5 <CA_min / CA_Aver<2

[0459] In Mathematical Expression 30, CA_min represents the minimum effective diameter of the object side surface and the sensor side surface of the lens, and CA_Aver represents the average value of the effective diameters of the object side surface and the sensor side surface of the lens. If Mathematical Expression 30 is satisfied, the optical system can be sized to obtain a slim and compact structure while maintaining optical performance. In the first and second embodiments, Mathematical Expression 30 may preferably satisfy 0.5 <CA_min / CA_Aver<1。

[0460] [Mathematical expression 31]

[0461] 1 <CA_max / (2*ImgH)<3

[0462] Mathematical expression 31 shows that CA_max represents the maximum effective diameter of the object side surface and the sensor side surface of the lens, and Imgh is 1 / 2 of the length of the image sensor (300) diagonally relative to the optical axis. If mathematical expression 31 is satisfied, the optical system can maintain good optical performance and can be sized to obtain a slim and compact structure. In the first and second embodiments, mathematical expression 31 can preferably satisfy 1 <CA_max / (2*ImgH)<2。

[0463] [Mathematical expression 32]

[0464] 1 <TD / CA_max<4

[0465] In mathematical expression 32, TD is the optical axis distance from the center of the object side surface of the first lens (101, 201) to the center of the sensor side surface of the last lens, and CA_max is the maximum effective diameter of the object side surface and the sensor side surface of the lens. If mathematical expression 32 is satisfied, the total optical axis distance and the maximum effective diameter of the lens can be set, and thus the lens can be sized to obtain good optical performance. In the first and second embodiments, mathematical expression 32 can preferably satisfy 2 <TD / CA_max<3。

[0466] [Mathematical expression 33]

[0467] 0 <F / L1R1<1

[0468] In Mathematical Expression 33, F is the effective focal length of the optical system, and L1R1 is the radius of curvature of the object-side surface of the first lens (101, 201). If Mathematical Expression 33 is satisfied, incident light and its influence on TTL can be controlled. In the first and second embodiments, Mathematical Expression 33 may preferably satisfy 0.5≤F / L1R1<1.

[0469] [Mathematical expression 34]

[0470] 1 < Max_th / Min_th < 3

[0471] In mathematical expression 34, Max_th is the thickness of the thickest region of the lens, and Min_th is the thickness of the thinnest region of the lens. The thickest thickness Max_th of the lens can be the center thickness (CT) of the lens, and the thinnest thickness Min_th of the lens can be the edge thickness (ET) of the lens, but the reverse is also possible. The thickest thickness Max_th of the lens can be the edge thickness (ET) of the lens, and the thinnest thickness Min_th of the lens can be the center thickness (CT) of the lens. The edge thickness (ET) is the thickness at the distal end of the effective diameter. If the mathematical expression 34 is satisfied, the optical system can adjust the influence on the effective focal length. In the first embodiment, the mathematical expression 34 can preferably satisfy the condition of 1 < MAX_th / MIN_th ≤ 1.5, and in the second embodiment, the mathematical expression 34 can preferably satisfy the condition of 2 < MAX_th / MIN_th ≤ 2.5.

[0472] Here, the ratio of the maximum thickness to the minimum thickness of the plastic lens can satisfy the following conditions. Max_PL_th is the thickness value of the thickest region of the plastic lens, and Min_PL_th is the thickness value of the thinnest region of the plastic lens. Max_PL_th can be the center thickness (CT) of the plastic lens, and Min_PL_th can be the edge thickness (ET) of the plastic lens. The edge thickness (ET) is the thickness at the distal end of the effective diameter. The reverse is also possible. Max_PL_th can be the edge thickness (ET) of the plastic lens, and Min_PL_th can be the center thickness (CT) of the plastic lens. The edge thickness (ET) means the thickness at the distal end of the effective diameter.

[0473] Condition 1: 1 < Max_PL_th / Min_PL_th < 2.5

[0474] When the lower limit of Condition 1 is less than the range, it is difficult to manufacture the plastic lens, that is, the plastic lens is made by injecting high-temperature resin and curing it at low temperature, and if the thickness difference is large, when the lens is cooled at low temperature, the shrinkage may be uneven, resulting in a high surface defect rate. In addition, if the range of Condition 1 is greater than the range of Condition 2, the plastic lens expands and contracts when the temperature changes from -40 degrees Celsius to 105 degrees Celsius, and the change rate of the shape of the lens is large, which may lead to a reduction in the performance of the optical system.

[0475] Preferably, the conditions of 1.0 < Max_PL_th / Min_PL_th < 1.8 and 1.0 < Max_PL_th / Min_PL_th < 1.5 can be satisfied.

[0476] [Mathematical Expression 35]

[0477] 0 < EPD / |L1R1| < 1

[0478] In Mathematical Expression 35, EPD means the size (mm) of the entrance pupil of the optical system (1000, 2000), and L1R1 means the radius of curvature of the first surface (S1) of the first lens (101, 201). If the optical system (1000, 2000) according to the embodiment satisfies Mathematical Expression 35, the optical system (1000, 2000) can control the incident light. In the first embodiment and the second embodiment, Mathematical Expression 35 can preferably satisfy the condition of 0.3 < EPD / |L1R1| ≤ 0.9.

[0479] [Mathematical Expression 36]

[0480] Po4 * Po5 < 0

[0481] In Mathematical Expression 36, Po4 is the refractive power value of the fourth lens (104, 204), and Po5 is the refractive power value of the fifth lens (105, 205). In other words, the refractive powers of the fourth lens (104) and the fifth lens (105) have opposite refractive powers, which can improve the aberration and effectively guide the light to the plastic lens. Under the condition of Po4 * Po5 > 0, the improvement effect of the chromatic aberration of the cemented lens is not significant.

[0482] [Mathematical Expression 37]

[0483] 15 < v5 - v4 < 30

[0484] In Mathematical Expression 37, v4 is the Abbe number of the fourth lens (104, 204), and V5 is the Abbe number of the fifth lens (105, 205). If Mathematical Expression 37 is satisfied, the difference between the Abbe numbers of at least two lenses forming the cemented lens can be maintained above a certain value, and the chromatic aberration can be improved. In the first embodiment and the second embodiment, Mathematical Expression 37 can preferably satisfy 20 ≤ v5 - v4 ≤ 28. If the cemented lens is less than the lower limit of Mathematical Expression 37, it may have little effect on improving the aberration characteristics of the optical system. Therefore, the difference in Abbe number between the object-side lens and the sensor-side lens in the cemented lens being greater than 20 and less than or equal to 28 can improve the aberration characteristics.

[0485] [Mathematical Expression 38]

[0486] 0 < |F1| / F < 10

[0487] Mathematical expression 38 is where F is the effective focal length of the optical system and F1 is the focal length of the first lens (101, 201). If mathematical expression 38 is satisfied, TTL applied to the vehicle optical system can be set. In the first embodiment, mathematical expression 38 may preferably satisfy 1<|F1| / F<7, and in the second embodiment, mathematical expression 38 may preferably satisfy 1<|F1| / F<8.

[0488] [Mathematical expression 39]

[0489] F_LG1 / F_LG2<0

[0490] In Mathematical Expression 39, F_LG1 is the focal length of the first lens group (LG1), and F_LG2 is the focal length of the second lens group (F_LG2). The focal length of the first lens group may have a negative value, and the focal length of the second lens group may have a positive value. If Mathematical Expression 39 is satisfied, the optical system (1000, 2000) may improve aberration characteristics such as chromatic aberration and distortion aberration. Mathematical Expression 39 may preferably satisfy 5<|F_LG1 / F_LG2|<8 in the first embodiment, and may preferably satisfy 5<|F_LG1 / F_LG2|<9 in the second embodiment.

[0491] [Mathematical expression 40]

[0492] 1 <nGL / nPL<2

[0493] In mathematical expression 40, nGL is the number of glass material lenses (pieces), and nPL is the number of plastic material lenses. By arranging the number of glass lenses to be more than one time and less than two times the number of plastic lenses in mathematical expression 40, the thickness of the optical system can be reduced, and the aspherical surface can provide more variable refractive power. In the first embodiment and the second embodiment, mathematical expression 40 can preferably satisfy 1 <nGL / nPL<1.5。

[0494] [Mathematical expression 41]

[0495] CA_L7≤CA_L1 <CA_L3

[0496] In Mathematical Expression 41, CA_L1 is an average effective diameter of the object side surface and the sensor side surface of the first lens (101, 201), CA_L3 is an average effective diameter of the object side surface and the sensor side surface of the third lens (103, 203), and CA_L7 is an average effective diameter of the object side surface and the sensor side surface of the seventh lens (107, 207). If Mathematical Expression 41 is satisfied, the first lens group and the second lens group can be provided, and aberration can be improved by the first lens of the second lens group (LG2). CA_L3 has the largest effective diameter in the optical system.

[0497] [Mathematical expression 42]

[0498] 0<ΣPL_CT / ΣGL_CT<2

[0499] In mathematical expression 42, ΣPL_CT is the sum of the center thicknesses of the plastic lens, and ΣGL_CT is the sum of the center thicknesses of the glass lens. If mathematical expression 42 is satisfied, the overall TTL can be controlled by establishing a relationship between the thickness of the plastic lens and the thickness of the glass lens relative to the TTL. Mathematical expression 42 may preferably satisfy 0.3<ΣPL_CT / ΣGL_CT<0.8 in the first embodiment, and may preferably satisfy 1<ΣPL_CT / ΣGL_CT<1.5 in the second embodiment.

[0500] [Mathematical expression 43]

[0501] 0<ΣPL_Index / ΣGL_Index<2

[0502] In mathematical expression 43, ΣPL_Index is the sum of the refractive index thickness at the d-line of the plastic lens, and ΣGL_Index is the sum of the refractive index at the d-line of the glass lens. If mathematical expression 43 is satisfied, the relationship between the refractive index of the plastic lens and the refractive index of the glass lens can be set to control the overall resolution. In the first embodiment, mathematical expression 43 may preferably satisfy 0.5<ΣPL_Index / ΣGL_Index<1, and in the second embodiment, mathematical expression 43 may preferably satisfy 1<ΣPL_Index / ΣGL_Index<1.5.

[0503] [Mathematical expression 44]

[0504] 10 <TTL<44

[0505] In mathematical expression 44, TTL (Total Trajectory Length) means the distance (mm) along the optical axis (OA) from the center of the first surface (S1) of the first lens (101, 201) to the top surface of the image sensor (300). By making TTL greater than 10 or greater than 20 in mathematical expression 44, an automotive optical system can be provided. In the first and second embodiments, mathematical expression 44 can preferably satisfy the condition of 30 < TTL ≤ 40 or TD < TTL.

[0506] [Mathematical expression 45]

[0507] 2 < ImgH < 10

[0508] Mathematical expression 45 can set the diagonal size (2 * ImgH) of the image sensor 300 and can provide an optical system with an automotive sensor size. In the first and second embodiments, mathematical expression 45 can preferably satisfy 4 ≤ ImgH < 6.

[0509] [Mathematical expression 46]

[0510] 1 < BFL < 3.5

[0511] In mathematical expression 46, BFL is the optical axis distance from the image sensor (300) to the center of the sensor side surface of the last lens. Satisfying mathematical expression 46 allows a set space for the filter (500) and the cover glass (400), and the spacing between the image sensor (300) and the last lens allows improved component assembly and improved coupling reliability. In the first and second embodiments, mathematical expression 46 can preferably satisfy 1.5 ≤ BFL ≤ 3. If BFL is less than the range of mathematical expression 46, some of the light traveling to the image sensor may not be transmitted to the image sensor, which may result in reduced resolution. If BFL exceeds the range of mathematical expression 46, noise light may be introduced, which may reduce the aberration characteristics of the optical system.

[0512] [Mathematical expression 47]

[0513] 3 < F < 40

[0514] Mathematical expression 47 can set the total focal length F to match the automotive optical system. In the first and second embodiments, mathematical expression 47 can satisfy 5 < F < 20.

[0515] [Mathematical expression 48]

[0516] FOV < 45

[0517] In mathematical expression 48, the field of view (FOV) refers to the field of view expressed in degrees of the optical system (1000, 2000), which can provide an automotive optical system with a field of view of less than 45 degrees. In the first and second embodiments, the FOV can preferably satisfy 20 ≤ FOV ≤ 40.

[0518] [Mathematical expression 49]

[0519] 1 < TTL / CA_max < 5

[0520] In mathematical expression 49, CA_max means the maximum effective diameter (mm) of the object-side surface and the sensor-side surface of a plurality of lenses, and TTL (total track length) means the distance (mm) on the optical axis (OA) from the vertex of the first surface (S1) of the first lens to the top surface of the image sensor (300). Mathematical expression 49 establishes the relationship between the total optical axis length and the maximum effective diameter of the optical system, which can provide an improved automotive optical system. In the first embodiment, mathematical expression 49 can preferably satisfy 1.5 < TTL / CA_max ≤ 3, while in the second embodiment, mathematical expression 49 can preferably satisfy 2 < TTL / CA_max ≤ 3.

[0521] [Mathematical expression 50]

[0522] 2 < TTL / ImgH < 10

[0523] Mathematical expression 50 defines TTL (total track length) as the distance (mm) on the optical axis (OA) from the vertex of the first surface (S1) of the first lens to the top surface of the image sensor (300), where ImgH is 1 / 2 of the diagonal size of the image sensor (300). If mathematical expression 50 is satisfied, the optical system (1000, 2000) can have a TTL for applications of an automotive image sensor (300), which can provide improved image quality. In the first embodiment, mathematical expression 50 can preferably satisfy 4 < TTL / ImgH < 10, while in the second embodiment, mathematical expression 50 can preferably satisfy 5 < TTL / ImgH < 10.

[0524] [Mathematical expression 51]

[0525] 0.1 < BFL / ImgH < 1

[0526] Mathematical expression 51 defines BFL as the optical axis distance from the image sensor (300) to the center of the sensor side surface of the last lens, and ImgH as 1 / 2 of the diagonal size of the image sensor (300). If mathematical expression 51 is satisfied, the optical system (1000, 2000) can obtain a back focal length (BFL) for determining the size of the image sensor (300) of the vehicle, can set the spacing between the last lens and the image sensor (300), and can have good optical properties at the center and periphery of the field of view (FOV). In the first and second embodiments, mathematical expression 51 can preferably satisfy 0.2 <BFL / ImgH<0.8。

[0527] [Mathematical expression 52]

[0528] 5 <TTL / BFL<20

[0529] Mathematical expression 52 defines TTL (total track length) as the distance from the vertex of the first surface (S1) of the first lens to the top surface of the image sensor (300) along the optical axis (OA) in mm, and defines BFL as the optical axis distance from the image sensor (300) to the center of the sensor side surface of the last lens. If mathematical expression 52 is satisfied, the optical system (1000, 2000) can obtain BFL. In the first and second embodiments, mathematical expression 52 can preferably satisfy 10 <TTL / BFL<15。

[0530] [Mathematical expression 53]

[0531] 1 <TTL / F<3

[0532] Mathematical expression 53 shows that TTL (total track length) is the distance (mm) from the vertex of the first surface (S1) of the first lens to the top surface of the image sensor (300) on the optical axis (OA), and F is the effective focal length of the optical system. Therefore, an optical system for a driver assistance system can be provided. In the first and second embodiments, mathematical expression 53 can preferably satisfy 1.5≤TTL / F≤2.5 or 2≤TTL / F≤2.5. When the optical system (1000, 2000) according to the embodiment satisfies mathematical expression 53, the optical system provided by the optical system (1000, 2000) can have an appropriate focal length within a set TTL range and can form an image while maintaining an appropriate focal length when the temperature changes from low to high. Below the lower limit of mathematical expression 53, the refractive power of the lens may need to be increased, making it difficult to correct spherical aberration or distortion aberration, and above the upper limit of mathematical expression 53, the lens may have a longer effective diameter or TTL, resulting in an excessively large acquisition lens system.

[0533] [Mathematical expression 54]

[0534] 3 <F / BFL<10

[0535] Mathematical expression 54 shows that F is the effective focal length of the optical system, and BFL is the optical axis distance from the image sensor (300) to the center of the sensor side surface of the last lens. If mathematical expression 54 is satisfied, the optical system (1000, 2000) can have a set field of view and an appropriate focal length, and a vehicle optical system can be provided. In addition, the optical system (1000, 2000) can minimize the gap (spacing) between the last lens and the image sensor (300), and thus can have good optical properties at the periphery of the field of view (FOV). In the first embodiment and the second embodiment, mathematical expression 54 can preferably satisfy 3 <F / BFL<6。

[0536] [Mathematical expression 55]

[0537] 1 <F / ImgH<5

[0538] Mathematical expression 55 indicates that F is the effective focal length of the optical system, and ImgH is 1 / 2 of the diagonal size of the image sensor (300). Such an optical system (1000, 2000) can have improved aberration characteristics at the size of the automotive image sensor (300). In the first and second embodiments, mathematical expression 55 can preferably satisfy 2 <F / ImgH<4。

[0539] [Mathematical expression 56]

[0540] 1 <F / EPD<5

[0541] Mathematical expression 56 shows that F is the effective focal length of the optical system, and EPD is the entrance pupil size. Therefore, the overall brightness of the optical system can be controlled. Mathematical expression 56 can preferably be set so that 1 <F / EPD<2。

[0542] [Mathematical expression 57]

[0543] 0 <BFL / LTD<0.3

[0544] Mathematical expression 57 shows that TD is the optical axis distance of the lens of the optical system (1000, 2000), and BFL is the optical axis distance from the image sensor (300) to the center of the sensor-side surface of the last lens. Therefore, the overall size of the optical system can be controlled while maintaining the resolution of the optical system. In the first embodiment and the second embodiment, mathematical expression 57 preferably satisfies 0 < BFL / TD < 0.1. If the conditional value of BFL / TD is greater than or equal to 0.1, BFL is designed to be large relative to TD, resulting in a large size of the entire optical system, which makes it difficult to miniaturize the optical system, and the distance between the seventh lens (107, 207) and the image sensor increases, which may increase the amount of unnecessary light passing through the seventh lens (107, 207) and the image sensor, which may lead to a reduction in aberration characteristics and thus a reduction in resolution.

[0545] [Mathematical expression 58]

[0546] 0 < EPD / Imgh / FOV < 0.2

[0547] Mathematical expression 58 can establish the relationship between the size of the entrance pupil (EPD), the length of 1 / 2 of the maximum diagonal length of the image sensor (Imgh), and the field of view. Therefore, the overall size and brightness of the optical system can be controlled. Mathematical expression 58 preferably satisfies 0 < EPD / Imgh / FOV < 0.1.

[0548] [Mathematical expression 59]

[0549] 5 < FOV / F# < 30

[0550] Mathematical expression 59 can establish the relationship between the field of view of the optical system and the F-number (F#). Mathematical expression 59 preferably satisfies 10 < FOV / F# < 25. Here, F# can be provided as 1.6 or less to provide a bright image.

[0551] [Mathematical expression 60]

[0552] 10 < |F2 / F5| < 220

[0553] Mathematical expression 60 shows that F2 is the focal length of the second lens (102, 202), and F5 is the focal length of the fifth lens (105, 205). Mathematical expression 60 can establish the relationship between the focal length of the second lens (102, 202) and the focal length of the fifth lens (105, 205). In the optical system (1000, 2000), the absolute value of the focal length of the second lens (102, 202) of plastic is formed to be maximum, and the absolute value of the focal length of the fifth lens (105, 205) of glass is formed to be minimum to improve the incident efficiency, and adjust the refractive power between the glass lens and the plastic lens to guide the light to the image sensor (300). In the first embodiment, mathematical expression 60 can preferably satisfy 210<|F2 / F5|<215, and in the second embodiment, mathematical expression 60 can preferably satisfy 10<|F2 / F5|<15.

[0554] [Mathematical expression 61]

[0555] 5<|F2 / F3|<110

[0556] In the mathematical expression 61, F2 is the focal length of the second lens (102, 202), and F3 is the focal length of the third lens (103, 203). In the optical system (1000, 2000), except for the cemented lens (145), in the optical system (1000, 2000), the absolute value of the focal length of the second lens (102, 202) made of plastic is formed to be maximum, and the absolute value of the focal length of the third lens (103, 203) made of glass is formed to be minimum, so as to improve the incident efficiency, and adjust the refractive power between the glass lens and the plastic lens to guide the light to the image sensor (300). In the first embodiment, the mathematical expression 61 may preferably satisfy 102<|F2 / F3|<108, and in the second embodiment, the mathematical expression 61 may preferably satisfy 5<|F2 / F3|<8.

[0557] [Mathematical expression 62]

[0558] 0.05<|Sag_i / (CA_i / 2)|<0.2(i=S1,S2,S3,S4)

[0559] Mathematical expression 62 can establish a relationship between the Sag value of the first surface to the fourth surface (S1, S2, S3, S4) of the first lens (101) and the second lens (102) and the effective diameter (CA). If this relationship is satisfied, the refractive power of the lens can be improved. Here, mathematical expression 62 further satisfies the condition of n1>1.7, so that the first lens (101) and the second lens (102) can collect light with sufficient power without designing the curvature radius of the first lens (101) and the second lens (102) within the effective diameter to be sharp.

[0560] [Mathematical expression 63]

[0561]

[0562] In mathematical expression 63, Z is Sag, which may mean the distance from any position on the aspherical surface to the vertex of the aspherical surface in the direction of the optical axis. Y may mean the distance from any position on the aspherical surface to the optical axis in the direction perpendicular to the optical axis. c may mean the curvature of the lens, and K may mean the Kohnig constant. In addition, A, B, C, D, E, and F may mean aspherical constants.

[0563] The optical system (1000, 2000) according to the embodiment may satisfy at least one or more of the mathematical expressions from Mathematical Expression 1 to Mathematical Expression 63. In this case, the optical system (1000, 2000) may have improved optical properties. More specifically, when the optical system (1000, 2000) satisfies at least one or more of the mathematical expressions from Mathematical Expression 1 to Mathematical Expression 63, the optical system (1000, 2000) may have improved resolution, and may have improved aberration characteristics and distortion characteristics. In addition, the optical system (1000, 2000) may have a back focal length (BFL) for applying an automotive image sensor (300), may compensate for a reduction in optical properties due to temperature changes, and may minimize the gap between the last lens and the image sensor (300) to have good optical performance at the center and periphery of the field of view (FOV).

[0564] Table 3 shows the entries of the above-mentioned mathematical expressions in the optical systems (1000, 2000) of the first exemplary embodiment and the second exemplary embodiment, which are related to the total track length (TTL) (mm), the back focal length (BFL), the effective focal length (F) (mm), ImgH (mm), the effective diameter (CA) (mm), the thickness (mm), TTL (mm) and TD (mm), which are the optical systems (1000, 2000) from the first surface (S1) to the fourteenth surface (S14). ), the optical axis distance of the first lens element to the seventh lens element (F1, F2, F3, F4, F5, F6, F7) (mm), the sum of the refractive indices, the sum of the Abbe numbers, the sum of the thicknesses (mm), the sum of the gaps between adjacent lenses, the effective diameter characteristics, the sum of the refractive indices of glass lenses, the sum of the refractive indices of plastic materials, the field of view (FOV) (degrees), the edge thickness (ET), the focal length of the first lens element and the second lens element, the F number, etc.

[0565] [Table 3]

[0566]

[0567]

[0568]

[0569] Table 4 shows the result values ​​of Mathematical Expression 1 to Mathematical Expression 64 described above for the optical systems (1000, 2000) of the first embodiment and the second embodiment. Referring to Table 4, it can be seen that the optical system (1000, 2000) satisfies at least one, at least two, or at least three of Mathematical Expression 1 to Mathematical Expression 64. More specifically, it can be seen that the optical system (1000, 2000) according to the embodiment satisfies all of Mathematical Expression 1 to Mathematical Expression 64. Therefore, the optical system (1000, 2000) can have good optical performance at the center and periphery of the field of view (FOV), and can have excellent optical properties.

[0570] [Table 4]

[0571]

[0572]

[0573]

[0574] Fig.29 is an example of a top view of a vehicle having a camera module or an optical system according to an exemplary embodiment of the present invention. Fig.29According to an embodiment of the present invention, a vehicle camera system includes an image generating unit (11), a first information generating unit (12), a second information generating unit (21, 22, 23, 24, 25, 26) and a control unit (14). The image generating unit (11) may include at least one camera module (31) arranged on the vehicle, and the at least one camera module may capture the front of the vehicle and / or the driver to generate an image in front of the vehicle or an image inside the vehicle. The image generating unit (11) may use the camera module (31) to generate an image of the surrounding environment of the vehicle in one or more directions and in front of the vehicle to generate an image of the surrounding environment of the vehicle. Here, the front image and the surrounding image may be digital images, and may include color images, black and white images, infrared images, etc. In addition, the front image and the surrounding image may include still images and videos. The image generating unit (11) may provide the driver image, the front image and the surrounding image to the control unit (14). Next, the first information generating unit (12) may include at least one radar and / or camera device arranged on the vehicle, which detects the front of the vehicle and generates the first detection information. Specifically, the first information generating unit (12) may be arranged on the vehicle, and generates the first detection information by detecting the position and speed of the vehicle located in front of the vehicle, the presence and position of pedestrians, etc.

[0575] The first detection information generated by the first information generating unit (12) can be used to control the vehicle to maintain a constant distance between the vehicle and the vehicle in front of it, and increase the stability of the vehicle operation in certain preset situations such as when the driver wants to change the driving lane of the vehicle or when reversing and parking. The first information generating unit (12) can provide the first detection information to the control unit (14). The second information generating unit (21, 22, 23, 24, 25, 26) can detect each side of the vehicle and generate second detection information based on the front image generated by the image generating unit (11) and the first detection information generated by the first information generating unit (12). Specifically, the second information generating unit (21, 22, 23, 24, 25, 26) can include at least one radar and / or camera device arranged on the vehicle, and can detect or image the position and speed of the vehicle located on the side of the vehicle. Here, the second information generating unit (21, 22, 23, 24, 25, 26) can be arranged at each of the two front corners, the side mirrors, and the rear center and the two rear corners of the vehicle.

[0576] The information generating unit of at least one of these automotive camera systems may include a camera module having the optical system described in the embodiment disclosed above, and may use information acquired through the front, rear, each side or corner area of ​​the vehicle to provide or process information to a user to protect the vehicle and objects from being affected by autonomous driving or peripheral safety.

[0577] For safety regulations, enhancement of autonomous driving functions, and increased convenience, multiple optical systems of camera modules according to exemplary embodiments of the present invention may be installed in a vehicle. In addition, the optical systems of camera modules are applied to vehicles as components for controlling systems such as lane keeping assist systems (LKAS), lane departure warning systems (LDWS), and driver monitoring systems (DMS). These automotive camera modules are able to maintain stable optical performance even when the ambient temperature changes, and are competitively priced, ensuring the reliability of automotive components.

[0578] Although the exemplary embodiments of the present invention have been described above with reference to the accompanying drawings, those skilled in the art will recognize that the present invention can be implemented in other specific forms without changing its technical concept or basic features. Therefore, it should be understood that the embodiments described above are exemplary in all aspects and are not intended to be limiting.

Claims

1. An optical system, comprising: A first lens to a seventh lens are arranged along an optical axis, wherein the first lens has a negative (-) refractive power, the composite refractive power of the second lens to the seventh lens is a positive (+) refractive power, the second lens among the first lens to the third lens has a smallest effective diameter, and the effective diameters of the sixth lens and the seventh lens are smaller than the effective diameter of the fifth lens.

2. The optical system according to claim 1, wherein: The second lens, the sixth lens, and the seventh lens are made of plastic, and the first lens and at least one of the third to fifth lenses are made of glass.

3. The optical system according to claim 1, wherein: Among the first to seventh lenses, the third lens has the largest effective diameter.

4. The optical system according to claim 3, wherein: The second lens has a meniscus shape that is convex toward the sensor.

5. The optical system according to any one of claims 1 to 3, wherein: The lens having the smallest absolute value of focal length among the first to seventh lenses is one lens among the third to fifth lenses.

6. The optical system according to claim 5, wherein: The absolute values ​​of the focal lengths of the third lens to the fifth lens satisfy the following conditional expression: <Conditional expression> |F3|≥|F4|≥|F5| (In the above conditional expressions, 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).

7. An optical system, comprising first to seventh lenses arranged along an optical axis, wherein: The first lens has negative (-) refractive power, wherein the composite refractive power of the second lens to the seventh lens has positive (+) refractive power, and wherein, among the first lens to the seventh lens, the absolute value of the focal length of the fifth lens is the smallest, and the absolute value of the focal length of the second lens is the largest.

8. The optical system according to claim 7, wherein: The first lens is made of glass, and the sixth lens and the seventh lens are made of plastic.

9. An optical system according to claim 7 or claim 8, comprising: A cemented lens in which a lens having a positive (+) refractive power and a lens having a negative (-) refractive power are cemented, wherein at least one of a lens disposed on an object side of the cemented lens and disposed closest to the cemented lens and a lens disposed on a sensor side of the cemented lens and disposed closest to the cemented lens has a convex shape on both sides.

10. The optical system according to claim 9, wherein: An absolute value of a radius of curvature of a sensor-side surface of the cemented lens is smaller than an absolute value of a radius of curvature of an object-side surface of the cemented lens.

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