Optical system and camera module

Abstract

An optical system according to one embodiment of the present invention includes first to seventh lenses arranged along an optical axis, wherein the first lens has negative (-) refractive power, the fourth lens has positive (+) refractive power, the fifth lens has negative (-) refractive power, the sixth lens has positive (+) refractive power, the seventh lens has negative (−) refractive power, and the thickness of the second lens on the optical axis is greater than the distance between the first lens and the second lens.

Description

Optical system and camera module

[0001] The present invention relates to an optical system for improved optical performance and a camera module including the same.

[0002] ADAS (Advanced Driving Assistance System) is an advanced driver assistance system that assists the driver in driving. It consists of sensing the situation ahead, judging the situation based on the sensed results, and controlling the vehicle's behavior based on the situation judgment. For example, ADAS sensor devices detect a vehicle ahead and recognize lanes. After the target lane, target speed, and forward target are determined, the vehicle's ESC (Electrical Stability Control), EMS (Engine Management System), and MDPS (Motor Driven Power Steering) are controlled. Representative examples of ADAS can be implemented as automatic parking systems, low-speed city driving assistance systems, and blind spot warning systems.

[0003] Sensor devices for detecting the situation ahead in ADAS include GPS sensors, laser scanners, forward radar, Lidar, etc., and the most representative one is a camera for taking pictures of the front, rear, and sides of the vehicle.

[0004] These cameras can be placed outside or inside a vehicle to detect the vehicle's surroundings. Furthermore, the cameras can be placed inside the vehicle to detect the driver and passengers. For example, the camera can photograph the driver from a position adjacent to the driver and detect the driver's health, drowsiness, and drinking status. Furthermore, the camera can photograph the passenger from a position adjacent to the passenger and detect the passenger's sleepiness, health, and other conditions, and provide the driver with information about the passenger.

[0005] In particular, the most crucial element for capturing an image from a camera is the imaging lens that forms the image. Recently, interest in high-performance features such as high image quality and high resolution has been increasing, and research is being conducted on optical systems comprising multiple lenses to achieve these features. However, there is a problem in that the characteristics of the optical system change when the camera is exposed to harsh environments, such as high temperature, low temperature, moisture, or high humidity, either inside or outside the vehicle. In this case, the camera faces the problem of difficulty in uniformly achieving excellent optical and aberration characteristics.

[0006] Therefore, a new optical system and camera that can solve the above-described problems are required.

[0007] The present invention seeks to provide an optical system and camera module having improved optical characteristics.

[0008] The present invention seeks to provide an optical system and camera module having excellent optical performance in low-temperature to high-temperature environments.

[0009] The present invention seeks to provide an optical system and camera module capable of preventing or minimizing changes in optical properties over a wide temperature range.

[0010] In order to solve the above technical problem, an optical system according to the present embodiment includes first to seventh lenses arranged along an optical axis, wherein the first lens has negative (-) refractive power, the fourth lens has positive (+) refractive power, the fifth lens has negative (-) refractive power, the sixth lens has positive (+) refractive power, and the seventh lens has negative (-) refractive power, and a thickness of the second lens on the optical axis is greater than a gap between the first lens and the second lens.

[0011] In the optical axis, the fourth lens may have a convex shape on both sides, and in the optical axis, the fifth lens may have a concave shape on both sides.

[0012] In the optical axis, the sixth lens may have a convex shape on both sides, and in the optical axis, the seventh lens may have a concave shape on both sides.

[0013] At least one of the first to seventh lenses may have an aspherical shape on the object side and the sensor side, and at least one of the first to seventh lenses may be made of glass.

[0014] At least one of the object-side surface and the sensor-side surface of the seventh lens may have an inflection point.

[0015] The second lens may have positive (+) refractive power, and the third lens may have positive (+) refractive power.

[0016] The following condition can be satisfied. <Condition> 9 < TTL < 13 (In the above condition, TTL means the distance on the optical axis from the object side of the first lens to the upper surface of the image sensor.)

[0017] The following condition can be satisfied. <Condition> 0.5 < ET7 / CT7 < 1 (In the above condition, ET7 is the edge thickness of the seventh lens, and CT7 is the thickness of the seventh lens on the optical axis.)

[0018] In order to solve the above technical problem, an optical system according to another embodiment of the present invention includes first to seventh lenses arranged along an optical axis, wherein the first lens has negative (-) refractive power, the third lens has positive (+) refractive power, the fifth lens has negative (-) refractive power, the sixth lens has positive (+) refractive power, and the seventh lens has negative (-) refractive power, and among the first to seventh lenses, the effective diameter of the first lens is the largest, and the effective diameter of the third lens is the smallest.

[0019] Among the first to seventh lenses on the optical axis, the thickness of the second lens may be the largest.

[0020] Among the first to seventh lenses on the optical axis, the thickness of the seventh lens may be the smallest.

[0021] In the optical axis, the sixth lens may have a convex shape on both sides, and in the optical axis, the seventh lens may have a concave shape on both sides.

[0022] The following condition can be satisfied. <Condition> 1 < |F4 / F5| < 2 (In the above condition, F4 is the focal length of the fourth lens, and F5 is the focal length of the fifth lens.)

[0023] The following condition can be satisfied. <Condition> 2 < F < 4 (In the above condition, F represents the focal length of the entire optical system.)

[0024] The following condition can be satisfied. <Condition> 100 < FOV_H < 110 (In the above condition, FOV_H means the horizontal angle of view of the optical system.)

[0025] An optical system and camera module according to an embodiment may have improved optical characteristics. Specifically, in the optical system according to an embodiment, a plurality of lenses may have set thicknesses, refractive powers, and spacings from adjacent lenses. Accordingly, the optical system and camera module according to the embodiment may have improved MTF characteristics, aberration control characteristics, resolution characteristics, etc. within a set field of view range, and may have good optical performance in the periphery of the field of view.

[0026] In addition, the optical system and camera module according to the embodiment can have good optical performance in a low temperature to high temperature range (-40℃ to 105℃). Specifically, a plurality of lenses included in the optical system can have set materials, refractive powers, and refractive indices. Accordingly, when the refractive index of each lens changes according to a temperature change and the focal length of each lens changes due to this, mutual compensation can be made by the plastic lens and the glass lens. That is, the optical system can effectively perform refractive power distribution in a low temperature to high temperature range, and can prevent or minimize changes in optical characteristics in a low temperature to high temperature range. Therefore, the optical system and camera module according to the embodiment can maintain improved optical characteristics in various temperature ranges.

[0027] Furthermore, the optical system and camera module according to the embodiment can satisfy the set angle of view and implement excellent optical characteristics through a combination of plastic and glass lenses. This allows the optical system to provide a slimmer vehicle camera module. Accordingly, the optical system and camera module can be used in various applications and devices, and can maintain excellent optical characteristics even in harsh temperature environments, such as when exposed to the exterior of a vehicle or in the high temperatures of a vehicle interior during the summer.

[0028] FIG. 1 is a side cross-sectional view of an optical system and a camera module having the same according to a first embodiment.

[0029] Figure 2 is a table showing the aspherical coefficients of lenses in the optical system of Figure 1.

[0030] Fig. 3 is a table showing the Sag values ​​of the lens surfaces of the first to seventh lenses in the optical system of Fig. 1.

[0031] Fig. 4 is a graph showing data on the diffraction MTF (Modulation Transfer Function) at RGB wavelengths of the optical system of Fig. 1.

[0032] Figure 5 is a graph showing data on the diffraction MTF at the IR wavelength of the optical system of Figure 1.

[0033] Fig. 6 is a graph showing data on the aberration characteristics of the optical system of Fig. 1 at room temperature.

[0034] Fig. 7 is a side cross-sectional view of an optical system and a camera module having the same according to a second embodiment.

[0035] Fig. 8 is a table showing the aspherical coefficients of lenses in the optical system of Fig. 7.

[0036] Fig. 9 is a table showing the Sag values ​​of the lens surfaces of the first to seventh lenses in the optical system of Fig. 7.

[0037] Figure 10 is a graph showing data on the diffraction MTF (Modulation Transfer Function) at RGB wavelengths of the optical system of Figure 7.

[0038] Figure 11 is a graph showing data on the diffraction MTF at the IR wavelength of the optical system of Figure 7.

[0039] Fig. 12 is a graph showing data on the aberration characteristics of the optical system of Fig. 7 at room temperature.

[0040] FIG. 13 is an example of a vehicle having an optical system according to an embodiment of the invention.

[0041] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings.

[0042] However, the technical idea of ​​the present invention is not limited to some of the embodiments described, but can be implemented in various different forms, and within the scope of the technical idea of ​​the present invention, one or more of the components between the embodiments can be selectively combined or substituted for use.

[0043] In addition, terms (including technical and scientific terms) used in this embodiment may be interpreted as having a meaning that can be generally understood by a person of ordinary skill in the technical field to which this embodiment belongs, unless explicitly and specifically defined and described, and terms that are commonly used, such as terms defined in a dictionary, may be interpreted in consideration of the contextual meaning of the relevant technology.

[0044] Additionally, the terms used in this embodiment are for the purpose of describing the embodiments and are not intended to limit the present invention.

[0045] In this specification, the singular may also include the plural unless specifically stated otherwise in the phrase, and when it is described as “A and / or at least one (or more) of B, C”, it may include one or more of all combinations that can be combined with A, B, C.

[0046] Additionally, in describing the components of this embodiment, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only intended to distinguish the components from other components, and are not intended to limit the nature, order, or sequence of the components.

[0047] And, when a component is described as being 'connected', 'coupled', or 'connected' to another component, it may include not only cases where the component is 'connected', 'coupled', or 'connected' directly to the other component, but also cases where the component is 'connected', 'coupled', or 'connected' by another component between the component and the other component.

[0048] Additionally, when described as being formed or arranged "above" or "below" each component, "above" or "below" includes not only cases where the two components are in direct contact with each other, but also cases where one or more other components are formed or arranged between the two components. Furthermore, when expressed as "above" or "below," the meaning may include not only the upward direction but also the downward direction based on one component.

[0049] In the description of the invention, the "object side" may mean a surface of the lens facing the object side with respect to the optical axis (OA), and the "sensor side" may mean a surface of the lens facing the imaging surface (image sensor) with respect to the optical axis. The "object side" may be the "object side," and the "sensor side" may be the "image side." A convex surface of a lens may mean a convex shape in the optical axis or the paraxial region, and a concave surface of a lens may mean a concave shape in the optical axis or the paraxial region. The radius of curvature, the center thickness, and the optical axis spacing between lenses described in the table for lens data may mean values ​​(unit: mm) in the optical axis. The vertical direction may mean a direction perpendicular to the optical axis, and the end of a lens or lens surface may mean the end of an effective area of ​​a lens through which incident light passes. The size of the effective diameter of the lens surface may have a measurement error of up to ±0.4 mm depending on the measurement method, etc. The above-mentioned near-axis region refers to a very narrow region near the optical axis, and is a region where the distance that a light ray falls from the optical axis (OA) is almost 0. Hereinafter, the meaning of the optical axis may include the center of each lens or a very narrow region near the optical axis.

[0050]

[0051] As shown in FIGS. 1 and 7, the optical systems (1000, 1100) according to the first and second embodiments of the present invention may include five or more lenses. The optical systems (1000, 1100) and the camera modules having the optical systems may be mounted inside or outside a vehicle to monitor the driver or sense external objects or lanes. The material of the lenses may be selected from glass or plastic, and the coefficient of linear expansion of glass is lower than that of plastic. Accordingly, glass lenses are employed to suppress changes in the focal imaging position due to temperature changes.

[0052] Existing glass materials have high durability, making them difficult to physically mold, and there were limitations in manufacturing the lens surface as an aspherical surface. The lens applied to the optical system (1000, 1100) according to the first and second embodiments of the present invention can be composed of a lens made of glass having an aspherical surface. A glass injection mold (GIM) can be manufactured by manufacturing a mold using a DTM (Diamond Turning Machine) which is the same as a plastic injection process, and can manufacture a curved shape of the lens surface. When a curved shape is applied to the lens surface, it can be easy to control aberration in the peripheral field (off-axis) away from the optical axis, and the TTL can be reduced, thereby miniaturizing the entire optical system.

[0053] Conventional glass lenses require post-processing such as polishing, and glass molds (GM) are processed through raw material processing and molding processes, but glass injection molds (GIMs) can be manufactured solely through injection molding, which is advantageous as it requires fewer processes and saves on materials and manufacturing costs. In addition, GIM materials feature excellent tolerances because injection molding is performed using a mold manufactured to within 1 um. In addition, GIM materials can provide excellent compensation for various aberrations such as spherical and chromatic aberrations through their aspherical shape, and can minimize distortion in the peripheral area. In addition, because GIM materials are made of glass, their optical performance can be guaranteed even when temperature changes.

[0054]

[0055] The optical system (1000, 1100) may include n lenses, where the nth lens may be the last lens adjacent to the image sensor (500), and the (n-1)th lens may be the lens closest to the last lens. n is an integer greater than or equal to 5, for example, 5 to 8.

[0056] Within the optical system (1000, 1100), at least one lens closest to the object may be made of glass. Three or more lenses, for example, three to five lenses, closest to the object may be made of glass. Since the rate of contraction and expansion of glass lenses due to temperature changes is smaller than that of plastic lenses, the glass lenses may be arranged in an area adjacent to the outside within the lens barrel.

[0057] At least one lens closest to the image sensor (500) within the optical system (1000, 1100) may be made of glass. For example, at least two lenses closest to the image sensor (500) may be made of glass, and preferably, at least two lenses adjacent to the image sensor (500) may be made of glass. That is, since the n-th and n-1-th lenses in the optical system (1000, 1100) are arranged as glass lenses, various aberrations can be corrected for the light incident on the image sensor (500).

[0058]

[0059] Among the lenses of the optical system (1000, 1100), the lens with the highest refractive index can be positioned adjacent to the object. The highest refractive index can be 1.8 or higher. The chromatic dispersion of light incident on the lens with the highest refractive index can be increased, and the center thickness can be made thinner than the edge thickness. In addition, since the lens with the highest refractive index is positioned on the object side, the radius of curvature of the second and subsequent lenses can be easily changed, and the center thickness can be increased.

[0060] Within the optical system (1000, 1100), a lens having a maximum effective diameter can be placed at the center of the object side and the sensor side. The effective diameter of the lens can increase and then decrease as it moves from the object side to the sensor side. The effective diameter of the lens can decrease and then increase and then decrease again as it moves from the object side to the sensor side. Through this, since the light incident on the optical system (1000, 1100) is structured to move away from the optical axis and then return to the optical axis, the optical system (1000, 1100) can form a stable optical path.

[0061] The effective diameter may be the diameter of the effective area where effective 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 on the object side of each lens and the effective diameter on the sensor side. The "diameter of the lens 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 the flange of the lens is not illustrated in FIGS. 1 and 7, the flange may be a portion that protrudes perpendicular to the optical axis from the side of the lens so that the lens is coupled to the barrel. The flange may not receive effective light. A spacer may be additionally arranged between the flanges of different lenses so that the lenses are coupled to the barrel.

[0062] Each of the lenses (101-107, 201-207) may include an effective area and an ineffective area. The effective area may be an area through which light incident on each of the lenses passes. In other words, the effective area may be defined as an effective area or effective diameter through which the incident light is refracted to implement optical characteristics. The ineffective area may be arranged around the periphery of the effective area. The ineffective area may be an area through which effective light is not incident from a plurality of lenses. In other words, the ineffective area may be an area unrelated to the optical characteristics. In addition, an end of the ineffective area may be an area fixed to a lens barrel or the like that accommodates the lens.

[0063]

[0064] Within the optical system (1000, 1100), the TTL (Total top length) may be more than 1 time, for example, more than 1 time and less than 2 times, than Imgh. The TTL (Total track length) is the distance from the center of the object-side surface of the first lens to the top surface of the image sensor (500) on the optical axis (OA). Imgh is the maximum diagonal length of the image sensor (500) on the optical axis (OA). Within the optical system (1000, 1100), the effective focal length (EFL) is 2 mm or more and 4 mm or less, and the horizontal field of view (FOV_H) is provided to be more than 100 degrees and less than 110 degrees, so that it can be provided as a standard optical system in a vehicle camera module. For example, the optical system and the camera module according to the embodiment can be applied to a camera for an ADAS (Advanced Driving Assistance System) installed inside or outside a vehicle.

[0065] The optical system (1000, 1100) can provide a vehicle lens optical system by setting the TTL / Imgh condition to be 1 or more and 2 or less, for example, to be 1.3 or more and 1.8 or less. Accordingly, the optical system (1000, 1100) can provide an image without exaggeration or distortion of the formed image.

[0066]

[0067] The effective diameter is the diameter or length of the effective area where light is incident. The length of the image sensor (500) is the maximum length of the diagonal in the direction orthogonal to the optical axis (OA). The number of lenses having an effective diameter larger than the length of the image sensor (500) within the optical system (1000, 1100) is 10% or less, and the number of lenses having an effective diameter smaller than the length of the image sensor (500) may be 80% or more or 90% or less.

[0068] The effective diameter of the lens closest to the object side within the lens unit (100, 200) may be smaller than the effective diameter of the lens closest to the image sensor (500). Accordingly, the brightness of the optical system can be controlled. The effective diameter may be the average effective diameter of the object side and the sensor side of each lens. By controlling the size of the effective diameter of each lens, the optical system (1000, 1100) can control the incident light to compensate for the deterioration of optical characteristics due to resolution and temperature change, improve chromatic aberration control characteristics, and improve the vignetting characteristics of the optical system (1000, 1100).

[0069] The lens unit (100, 200) may include a first lens (101, 201), a second lens (102, 202), a third lens (103, 203), a fourth lens (104, 204), a fifth lens (105, 205), a sixth lens (106, 206), and a seventh lens (107, 207) aligned from the object side toward the sensor side along the optical axis.

[0070] The lens unit (100, 200) may be arranged in a camera module having an inner barrel on one side or the entire inner surface of a lens barrel. The lens unit (100, 200) may be arranged in a camera module having a plurality of inner barrels around different lenses of the lens barrel. The lens unit (100, 200) may be arranged in a camera module having a first inner barrel in contact with the outer surface of at least one lens of the lens barrel and a second inner barrel in contact with the outer surface of at least one lens. The lens unit (100, 200) may be arranged in a camera module having a plurality of inner barrels each arranged between the outer surface of at least one or two or more lenses and the lens barrel. The lens unit (100, 200) may be arranged in a camera module in which the plurality of inner barrels have a material different from the material of the lens barrel.

[0071] Some of the lenses constituting the lens unit (100, 200) may be arranged in the lens barrel, and at least some of the lenses may be arranged in an inner barrel arranged within the lens barrel. Through this, the optical system (1000, 1100) can maintain resolution according to temperature changes. The lens unit (100, 200) may be arranged in a camera module having different barrels to minimize decentering of the lenses that expand according to temperature changes. The lens barrel in which the lens unit (100, 200) is arranged has a plurality of inner barrels within the lens barrel, thereby maintaining the resolution of the optical system according to temperature changes and suppressing deformation of the lenses.

[0072] The minimum effective diameter within the lens unit (100, 200) may be in the range of 2 mm to 3 mm, and the maximum effective diameter may be in the range of 6 mm to 8 mm. In addition, the optical system (1000, 1100) may control incident light to improve resolution and chromatic aberration control characteristics, and may improve vignetting characteristics of the optical system (1000, 1100).

[0073]

[0074] The optical system (1000, 1100) or camera module may include an image sensor (500). The image sensor (500) can detect light and convert it into an electrical signal. The image sensor (500) can detect light that sequentially passes through the lens unit (100, 200). The image sensor (500) may include an element capable of detecting incident light, such as a charge-coupled device (CCD) or a complementary metal oxide semiconductor (CMOS). Here, the number of lenses having an effective diameter smaller than the length of the image sensor (500) may be 5 to 7.

[0075]

[0076] The optical system (1000, 1100) or camera module may include a filter (600). The filter (600) may be positioned between the last lens and the image sensor (500). The filter (600) may be positioned between the lens closest to the sensor side among the lenses of the lens unit (100, 200) and the image sensor (500). For example, the filter (600) may be positioned between the nth lens and the image sensor (500).

[0077] The cover glass is placed between the filter (600) and the image sensor (500), and protects the upper portion of the image sensor (500) and can prevent a decrease in the reliability of the image sensor (500). The cover glass can be removed. The cover glass may be a protective glass.

[0078] The filter (600) may include an infrared filter or an infrared cut-off filter (IR cut-off). The filter (600) may allow light of a set wavelength band to pass through and filter out light of a different wavelength band. When the filter (600) includes an infrared filter, it may block radiant heat emitted from external light from being transmitted to the image sensor (500). In addition, the filter (600) may transmit visible light and reflect infrared light.

[0079] The optical system (1000, 1100) according to the embodiment may include an aperture (Stop). The aperture can control the amount of light incident on the optical system (1000, 1100). In the lenses arranged between the object and the aperture, the effective diameter of the lens surface tends to increase from the object side to the aperture. In the lens surfaces arranged between the aperture and the sensor, the effective diameter of the lens surfaces tends to decrease from the aperture to the sensor side. The tendency for the effective diameter of the lens surfaces to increase or decrease does not only mean the case where the effective diameter of the lens surfaces increases or decreases. For example, it also includes the case where the effective diameter of the lens surfaces increases and then decreases as it goes from the aperture to the sensor side.

[0080]

[0081] In the optical systems (1000, 1100) of the first and second embodiments, the sum of the refractive indices of the lenses of the lens unit (100, 200) may be 8 or more, for example, in the range of 10 to 13, and the average of the refractive indices may be 1.7 to 1.8. The sum of the Abbe numbers of each of the lenses may be 270 or more, for example, in the range of 280 to 320, and the average of the Abbe numbers may be 50 or less, for example, in the range of 40 to 45. The sum of the central thicknesses of the entire lens may be 5 mm or more, for example, in the range of 5 mm to 10 mm, and the average of the central thicknesses may be in the range of 0.8 mm to 1.2 mm. The sum of the central spacings between the lenses on the optical axis (OA) may be 2 mm or more, for example, in the range of 2 mm to 3.5 mm, and may be less than the sum of the central thicknesses of the lenses. Additionally, the average value of the effective diameter of each lens surface (S1-S14) of the lens unit (100, 200) can be provided in the range of 3 mm or more, for example, 4 mm to 6 mm.

[0082]

[0083] In the optical system according to the first and second embodiments of the invention, the angle of view (diagonal) may be 150 degrees or less, for example, in the range of 120 to 140 degrees. The F number of the optical system or the camera module may be 2.4 or less, for example, in the range of 1.4 to 3.0 or in the range of 2.0 to 2.5. The vehicle optical system may have a horizontal field of view (FOV_H) in the Y-axis direction that may be greater than 90 degrees and less than 120 degrees, for example, in the range of 100 to 110 degrees. In addition, the vertical field of view is provided at an angle smaller than the horizontal field of view, and may be 100 degrees or less, for example, in the range of 75 to 90 degrees. The horizontal field of view (FOV_H) is an angle of view based on the horizontal length of the sensor. Accordingly, it is possible to suppress a change in the focus imaging position due to temperature change, and provide a vehicle camera in which various aberrations are well corrected.

[0084] Because the optical systems used in vehicle cameras typically monitor road conditions, they can be designed based on the horizontal field of view, rather than the entire field of view. The optical system according to this embodiment is designed with a certain margin based on the inscribed circle of the image sensor. This ensures guaranteed optical performance within the range that satisfies the horizontal field of view (FOV_H).

[0085]

[0086] In order to more effectively prevent scratches caused by foreign substances or objects placed inside a vehicle, a glass lens may be used as the first lens (101, 201), and the object-side surface of the first lens (101, 201) may have a gently curved shape so as not to come into contact with external structures. This minimizes the occurrence of scratches due to contact with external structures. For driver monitoring, front / rear photography of the vehicle, lane detection, and detection of debris around the vehicle while the vehicle is being driven, the horizontal angle of view may be greater than 90 degrees and less than 120 degrees, for example, in the range of 100 degrees to 110 degrees. This horizontal angle of view may be a preset angle for an advanced driver assistance system (ADAS).

[0087] The optical system (1000, 1100) according to the embodiment may further include a reflective member for changing the path of light. The reflective member may be implemented as a prism that reflects incident light of the optical system (1000, 1100) toward the lenses. Hereinafter, the optical system according to the embodiment will be described in detail.

[0088]

[0089] An optical system according to a first embodiment of the invention will be described.

[0090] FIG. 1 is a side cross-sectional view of an optical system according to a first embodiment and a camera module having the same, FIG. 2 is a table showing aspherical coefficients of lenses in the optical system of FIG. 1, FIG. 3 is a table showing Sag values ​​of lens surfaces of first to seventh lenses in the optical system of FIG. 1, FIG. 4 is a graph showing data on diffraction MTF (Modulation Transfer Function) at RGB wavelengths of the optical system of FIG. 1, FIG. 5 is a graph showing data on diffraction MTF at IR wavelengths of the optical system of FIG. 1, and FIG. 6 is a graph showing data on aberration characteristics at room temperature of the optical system of FIG. 1.

[0091] Referring to FIG. 1, the optical system (1000) includes a lens unit (100), and the lens unit (100) may include a first lens (101) to a seventh lens (107). The first to seventh lenses (101 to 107) may be sequentially arranged along the optical axis (OA) of the optical system (1000). Light corresponding to information about an object may pass through the first lens (101) to the seventh lens (107) and a filter (600) and be incident on the image sensor (500).

[0092] The first lens (101) may be arranged closest to the object side. The first lens (101) may be arranged farthest from the sensor side. The first lens (101) may have negative (-) refractive power on the optical axis (OA). The first lens (101) may include a plastic material or a glass material, and may be made of glass, for example. The first lens (101) made of glass can reduce changes in the center position and radius of curvature due to temperature changes in the surrounding environment, and can protect the incident side surface of the optical system (1000).

[0093] The first surface (S1) on the object side of the first lens (101) with respect to the optical axis may be convex, and the second surface (S2) on the sensor side may be concave. The first lens (101) may have a concave meniscus shape toward the sensor side. The first lens (101) may have a convex meniscus shape toward the object side. The first lens (101) is made of glass 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 and second surfaces (S1, S2) may be provided as S1 and S2 of L1 in FIG. 2.

[0094] The refractive index (n1) of the first lens (101) can satisfy the condition of n1>1.5 or n1>1.52. If the refractive index (n1) of the first lens (101) satisfies the condition, the radius of curvature of the first and second lenses (101, 102) can be increased, and lens manufacturing can be facilitated. If the refractive index (n1) of the first lens (101) is smaller than the condition, the lens surface must be formed to be sharply concave or convex in order to increase the refractive power of the first and second lenses (101, 102). In this case, lens manufacturing is not easy, the lens defect rate increases, and this may cause a decrease in yield.

[0095]

[0096] The second lens (102) may be arranged second from the object side. The second lens (102) may be arranged 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 positive (+) refractive power in the optical axis (OA). The second lens (102) may include a plastic or glass material. For example, the second lens (102) may be provided as a glass material.

[0097] The object-side third surface (S3) of the second lens (102) with respect to the optical axis (OA) may be convex, and the sensor-side fourth surface (S4) may be convex. The second lens (102) may have a convex shape on both sides. The second lens (102) may be made of glass 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 and fourth surfaces (S3, S4) may be provided as S1 and S2 of L2 in FIG. 2.

[0098] The third surface (S3) of the second lens (102) may have a critical point from the optical axis (OA) to the end of the effective area. When the third surface (S3) has a critical point, it may be located in a range of 50% to 85%, preferably 70% to 80%, of the effective radius (r42) from the optical axis (OA). The critical point of the fourth surface (S4) may be located in a range of 1 mm to 1.8 mm, preferably 1 mm to 1.4 mm, from the optical axis (OA).

[0099] The critical point of the third surface (S3) is a point where the sign of the slope value with respect to the optical axis (OA) and the direction perpendicular to the optical axis (OA) changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the slope value is 0. In addition, the critical point of the third surface (S3) may be a point where the slope value of the tangent line passing through the lens surface increases and then decreases, or a point where the slope value decreases and then increases. The fourth surface (S4) of the second lens (102) may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0100]

[0101] The third lens (103) may be arranged third from the object side. The third lens (103) may be arranged 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 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 provided as a glass material.

[0102] The fifth surface (S5) on the object side of the third lens (103) with respect to the optical axis may be concave, and the sixth surface (S6) on the sensor side may be convex. The third lens (103) may have a meniscus shape in which the sensor side is convex. The third lens (103) may have a meniscus shape in which the object side is concave. The third lens (103) is made of glass and may be aspherical. At least one or both of the fifth surface (S5) and the sixth surface (S6) may be aspherical. The aspherical coefficients of the fifth and sixth surfaces (S5, S6) may be provided as S1 and S2 of L3 in FIG. 2. At least one or both of the fifth surface (S5) and the sixth surface (S6) may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0103] The aperture (Stop) may be arranged around the sensor-side fourth surface (S4) of the second lens (102). The aperture (Stop) may be arranged around the object-side fifth surface (S5) of the third lens (103). The aperture can reduce the TTL within the field of view range, and the optical system can be miniaturized. Accordingly, a decrease in the yield by weight of the optical system can be prevented, and production efficiency can be improved. In addition, the optical system can be miniaturized by reducing the TTL at a horizontal field of view (FOV_H) of 125 degrees to 135 degrees.

[0104]

[0105] The fourth lens (104) may be arranged fourth from the object side. The fourth lens (104) may be arranged 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 positive (+) or negative (-) refractive power on the optical axis (OA). The fourth lens (104) may have positive (+) refractive power. The fourth lens (104) may include a plastic or glass material. For example, the fourth lens (104) may be provided as a glass material.

[0106] The object-side seventh surface (S7) of the fourth lens (104) with respect to the optical axis may be convex, and the sensor-side eighth surface (S8) may be convex. The fourth lens (104) may have a convex shape on both sides. The fourth lens (104) may be made of glass and may be aspherical. At least one or both of the seventh surface (S7) and the eighth surface (S9) may be aspherical. The aspherical coefficients of the seventh and eighth surfaces (S7, S8) may be provided as S1 and S2 of L4 in FIG. 2. At least one or both of the seventh surface (S7) and the eighth surface (S8) may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0107]

[0108] The fifth lens (105) may be arranged as the fifth lens from the object side. The fifth lens (105) may be arranged as the third lens 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 positive (+) or negative (-) refractive power on the optical axis (OA). The fifth lens (105) may have negative (-) refractive power. The fifth lens (105) may include a plastic or glass material. For example, the fifth lens (105) may be provided as a glass material.

[0109] With respect to the optical axis (OA), the ninth surface (S9) on the object side of the fifth lens (105) may be concave, and the tenth surface (S10) on the sensor side may be concave. The fifth lens (105) may have a shape in which both sides are concave with respect to the optical axis (OA). The fifth lens (105) may be made of glass and may be aspherical. At least one or both of the ninth surface (S9) and the tenth surface (S10) may be aspherical. The aspherical coefficients of the ninth and tenth surfaces (S9, S10) may be provided as S1 and S2 of L5 in FIG. 2. At least one or both of the ninth surface (S9) and the tenth surface (S10) may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0110]

[0111] The sixth lens (106) may be arranged as the sixth lens from the object side. The sixth lens (106) may be arranged as the second lens 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 positive (+) or negative (-) refractive power on the optical axis (OA). The sixth lens (106) may have positive (+) refractive power. The sixth lens (106) may include a plastic or glass material. For example, the sixth lens (106) may be provided as a glass material.

[0112] With respect to the optical axis (OA), the eleventh surface (S11) on the object side of the sixth lens (106) may be convex, and the twelfth surface (S12) on the sensor side may be convex. The sixth lens (106) may have a convex shape on both sides with respect to the optical axis (OA). The sixth lens (106) may be made of glass and may be aspherical. At least one or both of the eleventh surface (S11) and the twelfth surface (S12) may be aspherical. The aspherical coefficients of the eleventh and twelfth surfaces (S11, S12) may be provided as S1 and S2 of L6 in FIG. 2.

[0113] The eleventh surface (S11) of the sixth lens (106) may have a critical point from the optical axis (OA) to the end of the effective area. When the eleventh surface (S11) has a critical point, it may be located in a range of 70% to 90%, preferably 80% to 85%, of the effective radius (r42) from the optical axis (OA). The critical point of the eleventh surface (S11) may be located in a range of 1.5 mm to 2.4 mm, preferably 1.8 mm to 2.2 mm from the optical axis (OA). The twelfth surface (S12) of the sixth lens (106) may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0114]

[0115] The seventh lens (107) may be arranged closest to the sensor side. The seventh lens (107) may be arranged farthest from the object side. The seventh lens (107) may have positive (+) or negative (-) refractive power on the optical axis (OA). The seventh lens (107) may have negative (-) refractive power. The seventh lens (107) may include a plastic or glass material. For example, the seventh lens (107) may be made of glass.

[0116] The object-side 13th surface (S13) of the seventh lens (107) on the optical axis may be concave, and the sensor-side 14th surface (S14) may be concave. The seventh lens (107) may have a concave shape on both sides. The seventh lens (107) may be made of glass and may be aspherical. At least one or both of the 13th surface (S13) and the 14th surface (S14) may be aspherical. The aspherical coefficients of the 13th and 14th surfaces (S13, S14) may be provided as S1 and S2 of L7 in FIG. 2.

[0117] The 13th surface (S13) of the seventh lens (107) may be provided without a critical point from the optical axis (OA) to the end of the effective area. The 14th surface (S14) of the seventh lens (107) may have a critical point from the optical axis (OA) to the end of the effective area. When the 14th surface (S14) has a critical point, it may be located in a range of 50% to 70%, preferably in a range of 60% to 65%, of the effective radius (r72) from the optical axis (OA). The critical point of the 14th surface (S14) may be located in a range of 1.5 mm to 2.5 mm, preferably in a range of 1.8 mm to 2.2 mm from the optical axis (OA).

[0118] The critical point of the 14th surface (S14) is a point where the sign of the slope value with respect to the optical axis (OA) and the direction perpendicular to the optical axis (OA) changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the slope value is 0. In addition, the critical point of the 14th surface (S14) may be a point where the slope value of the tangent line passing through the lens surface increases and then decreases, or a point where the slope value decreases and then increases.

[0119]

[0120] LensSurfaceRadiusThicknessndvdSemiApertureFocal length1S1183.9050.8001.5360.493.565-3.868 S22.0181.109 1.808 2S38.3252.0001.9135.251.7258.722 S4-180.1460.366 1.208 3S5(Stop)-14.0180.7201.7452.621.0324.981 S6-3.0080.050 1.200 4S74.9821.1531.7354.671.4753.003 S8-3.5510.050 1.576 5S9-5.8070.4001.8522.521.534-2.776 S104.1880.811 1.740 6S118.2071.2781.822.522.5523.432 S12-3.8990.082 2.844 7S13-3.6840.4001.6236.542.952-3.824 S146.9930.180 3.239 FilterS15Infinity0.900 3.340Infinity S16Infinity0.702 3.465 Image Infinity0.000 3.640

[0121] Table 1 shows the surface number (Surface), radius of curvature (Radius), center thickness of each lens or distance between lens surfaces (Thickness), refractive index (Index,nd), Abbe number (Abbe,vd), effective radius (Semi Aperture), and focal length (Fcoal length) of the lens according to the first embodiment of the present invention. At this time, the unit of the radius of curvature and thickness or distance may be mm.

[0122]

[0123] Item ValueItem ValueF2.9ET11.319ΣIndex12.184ET21.989ΣAbbe284.59ET30.509ΣCT7.251ET40.501ΣCG2.468ET51.092CA_max7.28ET60.502CA_min2.063ET70 .628CA_Aver4.575F-number2.200CT_max2FOV_D130CT_min0.4FOV_V84CT_Aver1.0359FOV_H107EPD1.3396ImgH7.28BFL1.780SD5.124TD9.4TTL11

[0124] Table 2 shows the items of the mathematical formulas described above in the optical system (1000) of the embodiment, including the total track length (TTL) (mm), back focal length (BFL), effective focal length (F) (mm), ImgH (mm), effective diameter (CA) (mm), thickness (mm), TTL (mm), the optical axis distance from the first surface (S1) to the fourteenth surface (S14) TD (mm), the optical axis distance from the stop (Stop) to the fourteenth surface (S14) SD (mm), the sum of refractive indices, the sum of Abbe numbers, the sum of thicknesses (mm), the sum of spacings between adjacent lenses, the effective diameter characteristics, the diagonal angle of view (FOV_D) (Degree), the vertical angle of view (FOV_V) (Degree), the horizontal angle of view (FOV_H) (Degree), the edge thickness (ET), the F number, etc. of the optical system (1000).

[0125]

[0126] The center thicknesses of the first to seventh lenses (101 to 107) are represented by CT1 to CT7, the edge thicknesses at the ends of the effective areas of each lens are represented by ET1 to ET7, the center gap between two adjacent lenses is represented by CG1 to CG6, and the edge gaps between the edges of each lens are represented by EG1 to EG6. BFL (Back focal length) is the optical axis distance from the image sensor (500) to the center of the last lens. TTL is the optical axis distance from the center of the first surface (S1) of the first lens (101) to the upper surface of the image sensor (500).

[0127] As shown in FIG. 2, among the lenses of the lens unit (100) in the first embodiment, the lens surfaces of the first, second, third, fourth, fifth, sixth, and seventh lenses (101, 102, 103, 104, 105, 106, and 107) may include aspherical surfaces having a 30th-order aspherical surface coefficient. For example, the first, second, third, fourth, fifth, sixth, and seventh lenses (101, 102, 103, 104, 105, 106, and 107) may include lens surfaces having a 30th-order aspherical surface coefficient. As described above, since the aspherical surface having a 30th-order aspherical surface coefficient (a value other than "0") can significantly change the aspherical shape of the peripheral portion, the optical performance of the peripheral portion of the field of view (FOV) can be well corrected.

[0128] When comparing the absolute values ​​of the curvature radii of each lens, the curvature radii of the first surface (S1) of the first lens (101) on the optical axis (OA) may be the largest among the lenses, and the curvature radii of the second surface (S2) of the first lens (101) may be the smallest among the lenses. The difference between the maximum curvature radii and the minimum curvature radii may be 80 times or more, for example, in the range of 90 to 95 times.

[0129] Among the lenses, there may be 10 or more and 12 or fewer surfaces with an absolute value of curvature radius of 10 mm or less on the object side and sensor side. The sensor side (second surface (S2)) of the first lens (101), the object side (third surface (S3)) of the second lens (102), the sensor side (sixth surface (S6)) of the third lens (103), the object side (seventh surface (S7)) of the fourth lens (104), the sensor side (eighth surface (S8)) of the fourth lens (104), the object side (ninth surface (S9)) of the fifth lens (105), the sensor side (tenth surface (S10)) of the fifth lens (105), the object side (eleventh surface (S11)) of the sixth lens (106), the sensor side (twelfth surface (S12)) of the sixth lens (106), the object side (thirteenth surface (S13)) of the seventh lens (107), the sensor side (fourteenth surface (S14)) of the seventh lens (107) The absolute value of the radius of curvature may be 10 mm or less. Among the lenses, there may be at least one and no more than two surfaces on the object side and the sensor side whose absolute value of the radius of curvature is 10 mm or more and 20 mm or less.

[0130] The absolute value of the curvature radius of the object-side surface (the fifth surface (S5)) of the third lens (103) may be 10 mm or more and 20 mm or less. Among the lenses, there may be one or more and three or less surfaces of which the absolute value of the curvature radius is 150 mm or more among the object-side surface and the sensor-side surface. The absolute value of the curvature radius of the object-side surface (the first surface (S1)) of the first lens (101) and the sensor-side surface (the fourth surface (S4)) of the second lens (102) may be 150 mm or more.

[0131] The shape of the first lens (101) having a spherical shape can be designed to be gentle. If the aspherical surface is positioned at the frontmost part of the optical system (1000), the performance of the lens is improved, but the assemblability may be reduced. To improve the assemblability, the shape of the first lens (101) must be designed to be gentle. In order to minimize the influence on the lens placed on the sensor side when assembling the lens into the barrel, the first lens (101) can be designed to have almost no curvature.

[0132] The absolute value of the curvature radius of the first surface (S1) of the first lens (101) may be greater than the absolute value of the curvature radius of the second surface (S2). The absolute value of the curvature radius of the third surface (S3) of the second lens (102) may be less than the absolute value of the curvature radius of the fourth surface (S4). The absolute value of the curvature radius of the fifth surface (S5) of the third lens (103) may be greater than the absolute value of the curvature radius of the sixth surface (S6). The absolute value of the curvature radius of the seventh surface (S7) of the fourth lens (104) may be greater than the absolute value of the curvature radius of the eighth surface (S8). The absolute value of the curvature radius of the ninth surface (S9) of the fifth lens (105) may be greater than the absolute value of the curvature radius of the tenth surface (S10). The absolute value of the radius of curvature of the eleventh surface (S11) of the sixth lens (106) may be greater than the absolute value of the radius of curvature of the twelfth surface (S12). The absolute value of the radius of curvature of the thirteenth surface (S13) of the seventh lens (107) may be less than the absolute value of the radius of curvature of the fourteenth surface (S14).

[0133] The ratio of the radius of curvature of each lens can satisfy the following conditions.

[0134] Condition 1: 80 < |L1R1 / L1R2| < 100

[0135] Condition 2: 0.01 < |L2R1 / L2R2| < 0.05

[0136] Condition 3: 1 < |L3R1 / L3R2| < 5

[0137] Condition 4: 0.5 < |L4R1 / L4R2| < 1.5

[0138] Condition 5: 0.5 < |L5R1 / L5R2| < 1.5

[0139] Condition 6: 2 < |L6R1 / L6R2| < 2.5

[0140] Condition 7: 0.1 < |L7R1 / L7R2| < 1

[0141]

[0142] When describing the central thickness of the lenses based on the optical axis, the central thickness (CT2) of the second lens (102) is the largest among the lenses, and the central thickness (CT5) of the fifth lens (105) is the smallest among the lenses. The difference between the maximum and minimum central thicknesses among the lenses may be in the range of 1 mm or more and 3 mm or less.

[0143] The central thickness of each lens may satisfy any one of the following conditions:

[0144] Condition 1: CT2, CT4, CT6, CT7 > CT1 > CT3, CT5

[0145] Condition 2: CT2 > CT1, CT3, CT4, CT5, CT6, CT7

[0146] Condition 3: CT1, CT2, CT4, CT6, CT7 > CT3 > CT5

[0147] Condition 4: CT2, CT6 > CT4 > CT1, CT3, CT5, CT7

[0148] Condition 5: CT1, CT2, CT3, CT4, CT6, CT7 > CT5

[0149] Condition 6: CT2 > CT6 > CT1, CT3, CT4, CT5, CT7

[0150] Condition 7: CT2, CT4, CT6 > CT7 > CT1, CT3, CT5

[0151]

[0152] When describing the center spacing (CG) between the lenses, the center spacing (CG1) between the first lens (101) and the second lens (102) may be maximum, the center spacing (CG3) between the third and fourth lenses (103, 104) and the center spacing (CG4) between the fourth and fifth lenses (104, 105) may be minimum. The difference between the maximum center spacing and the minimum center spacing among the spaced lens spacings may be 1.0 mm or more, for example, in the range of 1.0 mm to 1.5 mm.

[0153] The center spacing between each lens can satisfy the conditions below.

[0154] Condition 1: CG1 > CG2, CG3, CG4, CG5, CG6

[0155] Condition 2: CG1, CG5 > CG2 > CG3, CG4, CG6

[0156] Condition 3: CG1, CG2, CG5, CG6 > CG3 = CG4

[0157] Condition 4: CG1 > CG5 > CG2, CG3, CG4, CG6

[0158] Condition 5: CG1, CG2, CG5 > CG6 > CG3, CG4

[0159]

[0160] Regarding the effective diameter, the lens having the maximum effective diameter may be placed between the first lens (101) closest to the object and the seventh lens (107) closest to the image sensor (500). The lens having the maximum effective diameter may be a glass lens. The lens having the maximum effective diameter may be the seventh lens (107). Here, the effective diameter is the average of the effective diameters of the object-side surface and the sensor-side surface of each lens. The lens surface having the maximum effective diameter may be the first surface (S1) of the first lens (101).

[0161] The lens having the minimum effective diameter may be any one of the glass material lenses, and for example, the effective diameter of the third lens (103) may be the minimum within the lens unit (100). The lens surface having the minimum effective diameter may be the fifth surface (S5) of the third lens (103).

[0162] The effective diameter of each lens can satisfy any one of the conditions below.

[0163] Condition 1: CA_L6, CA_L7 > CA_L1 > CA_L2, CA_L3, CA_L4, CA_L5

[0164] Condition 2: CA_L1, CA_L4, CA_L5, CA_L6, CA_L7 > CA_L2 > CA_L3

[0165] Condition 3: CA_L1, CA_L2, CA_L4, CA_L5, CA_L6, CA_L7 > CA_L3

[0166] Condition 4: CA_L1, CA_L5, CA_L6, CA_L7 > CA_L4 > CA_L2, CA_L3

[0167] Condition 5: CA_L1, CA_L6, CA_L7 > CA_L5 > CA_L2, CA_L3, CA_L4

[0168] Condition 6: CA_L7 > CA_L6 > CA_L1, CA_L2, CA_L3, CA_L4, CA_L5

[0169] Condition 7: CA_L7 > CA_L1, CA_L2, CA_L3, CA_L4, CA_L5, CA_L6

[0170]

[0171] Regarding the refractive index, the refractive index of the second lens (102) may be the highest among the lenses and may be greater than 1.8, for example, greater than 1.9. The first lens (101) may have the lowest refractive index among the lenses. For example, the refractive index of the first lens (101) may be the lowest among the lenses and 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 0.3 or more.

[0172] The refractive index of each lens can satisfy any of the conditions below.

[0173] Condition 1: n2, n3, n4, n5, n6, n7 > n1

[0174] Condition 2: n2 > n1, n3, n4, n5, n6, n7

[0175] Condition 3: n2, n5, n6 > n3 > n1, n4, n7

[0176] Condition 4: n2, n3, n5, n6 > n4 > n1, n7

[0177] Condition 5: n2 > n5 > n1, n3, n4, n6, n7

[0178] Condition 5: n2, n5 > n6 > n1, n3, n4, n7

[0179] Condition 6: n2, n3, n4, n5, n6 > n7 > n1

[0180]

[0181] Comparing the Abbe numbers, the Abbe number of the first lens (101) is the largest among the lenses and may be 50 or more. The Abbe number of the fifth lens (105) is the smallest among the lenses and may be 25 or less. The difference between the maximum Abbe number and the minimum Abbe number may be 30 or more. By providing the Abbe number of the first lens (101) as the largest and the Abbe number of the fifth lens (105) as the smallest, the chromatic dispersion of light traveling between the lenses made of glass can be controlled, and the chromatic dispersion between the lenses can be increased to guide it to the image sensor (500).

[0182] The Abbe number of each lens can satisfy any of the conditions below.

[0183] Condition 1: v1 > v2, v3, v4, v5, v6, v7

[0184] Condition 2: v1, v3, v4, v7 > v2 > v5, v6

[0185] Condition 3: v1, v4 > v3 > v2, v5, v6, v7

[0186] Condition 4: v1 > v4 > v2, v3, v5, v6, v7

[0187] Condition 5: v1, v2, v3, v4, v7 > v5 = v6

[0188] Condition 6: v1, v3, v4 > v7 > v2, v5, v6

[0189]

[0190] The focal lengths (F1, F5, F7) of the first, fifth, and seventh lenses (101, 105, and 107) may have negative (-) signs. The first, fifth, and seventh lenses (101, 105, and 107) may have negative (-) refractive power. The focal lengths (F2, F3, F4, F6) of the second, third, fourth, and sixth lenses (102, 103, 104, and 106) may have positive (+) signs. The second, third, and fourth lenses (102, 103, 104, and 106) may have positive (+) refractive power. The second, third, and fourth lenses (102, 103, and 104) having positive (+) refractive power may be arranged on the sensor side of the first lens (101) having negative (-) refractive power. Through this, light incident from the object side can move away from the optical axis direction and then gather again in the optical axis direction, thereby forming a stable optical path.

[0191]

[0192] Additionally, the fourth lens (104) and the fifth lens (105), which are adjacently arranged lenses, can satisfy the following conditions.

[0193] Condition 1: Refractive index of lens with positive refractive power < refractive index of lens with negative refractive power

[0194] Condition 2: Dispersion of a lens with positive refractive power > Dispersion of a lens with negative refractive power

[0195] Here, among the glass lenses, the fourth lens (104) has negative refractive power and the fifth lens (105) has positive refractive power, so according to conditions 1 and 2, the refractive index of the fourth lens (104) is smaller than the refractive index of the fifth lens (105), and the dispersion value of the fourth lens (104) is larger than the dispersion value of the fifth lens (105). Chromatic aberration occurring in a glass lens can be corrected by a glass lens. In addition, since the fourth lens (104) and the fifth lens (105), which are glass lenses arranged in succession, satisfy the conditions of a refractive index difference of 0.01 or more and 0.1 or less and an Abbe number difference of 20 or more and 50 or less, chromatic aberration occurring in a glass lens can be compensated for by a glass lens.

[0196] Optical systems suffer from chromatic aberration, and chromatic aberration is corrected by using cemented lenses or two lenses arranged in series. As the temperature changes from low to high, the lenses repeatedly contract and expand. Since the amount of change in lens characteristics due to temperature changes is the same for lenses made of the same material, it is effective to correct chromatic aberration between lenses made of the same material even when the temperature changes. Therefore, in the first embodiment of the present invention, chromatic aberration occurring in a glass lens is corrected by using the fourth lens (104) and the fifth lens (105).

[0197]

[0198] When comparing the focal lengths in absolute values, the focal length of the second lens (102) is the largest among the lenses, and may be 5 or more and 10 or less. Among the lenses, the second lens (102) made of glass may have the largest focal length and the smallest refractive power. The focal length of the fifth lens (105) is the smallest among the lenses, and the absolute value of the focal length of the fifth lens (105) may be 1 or more and 3 or less. Among the lenses, the fifth lens (105) made of glass may have the smallest focal length and the largest refractive power.

[0199] Among the lenses, the lens having the minimum focal length may be the fifth lens (105). The difference between the maximum focal length and the minimum focal length may be 3 or more or 5 or more. Accordingly, the optical system may have improved MTF characteristics, aberration control characteristics, resolution characteristics, etc. in the set field of view range, and may have good optical performance in the periphery of the field of view.

[0200] The absolute value of the focal length of each lens can satisfy any of the conditions below.

[0201] Condition 1: |f2|, |f3| > |f1| > |f4|, |f5|, |f6|, |f7|

[0202] Condition 2: |f2| > |f1|, |f3|, |f4|, |f5|, |f6|, |f7|

[0203] Condition 3: |f1|, |f2| > |f3|, |f4|, |f5|, |f6|, |f7|

[0204] Condition 4: |f1|, |f2|, |f3|, |f6|, |f7| > |f4| > |f5|

[0205] Condition 5: |f1|, |f2|, |f3|, |f4|, |f6|, |f7| > |f5|

[0206] Condition 6: |f1|, |f2|, |f3|, |f7| > |f6| > |f4|, |f5|

[0207] Condition 7: |f1|, |f2|, |f3| > |f7| > |f4|, |f5|, |f6|

[0208]

[0209] The thickness (T1) of the first lens (101) may be maximum at the edge and minimum at the center, and the maximum thickness is in the range of 1.5 to 2 times the minimum thickness. The thickness (T2) of the second lens (102) may be minimum at the edge and maximum at the center, and the maximum thickness is in the range of 1 to 1.5 times the minimum thickness. The thickness (T3) of the third lens (103) may be maximum at the center and minimum at the edge, and the maximum thickness is in the range of 1.2 to 1.5 times the minimum thickness. The thickness (T4) of the fourth lens (104) may be maximum at the center and minimum at the edge, and the maximum thickness is in the range of 2 to 2.5 times the minimum thickness. The thickness (T5) of the fifth lens (105) may be minimum at the center and maximum at the edge, and the maximum thickness is in the range of 2.5 to 3 times the minimum thickness. The thickness (T6) of the sixth lens (106) may be maximum at the center and minimum at the edge, and the maximum thickness is in the range of 2.5 to 3 times the minimum thickness. The thickness (T7) of the seventh lens (107) may be maximum at the center and minimum at the edge, and the maximum thickness is in the range of 1.2 to 1.5 times the minimum thickness.

[0210] The thickness of each lens can satisfy any of the conditions below.

[0211] Condition 1: 0.2 < CT1 / ET1 < 1, 1.5 < ET1 / CT1 < 2

[0212] Condition 2: 1 < CT2 / ET2 < 1.5, 0.5 < ET2 / CT2 < 1

[0213] Condition 3: 1 < CT3 / ET3 < 1.5, 0.5 < ET3 / CT3 < 1

[0214] Condition 4: 2 < CT4 / ET4 < 2.5, 0.2 < ET4 / CT4 < 1

[0215] Condition 5: 0.1 < CT5 / ET5 < 0.5, 2.5 < ET5 / CT5 < 3

[0216] Condition 6: 2.5 < CT6 / ET6 < 3, 0.1 < ET6 / CT6 < 0.5

[0217] Condition 7: 1 < CT7 / ET7 < 1.5, 0.5 < ET7 / CT7 < 1

[0218] Condition 8: 1 < ΣCT / ΣET < 1.5, 0.5 < ΣET / ΣCT < 1

[0219]

[0220] Among the gaps (G1-G6) between the lenses, the first gap (G1) between the first and second lenses (101, 102) may have a maximum in the center and a minimum in the edge. The second gap (G2) between the second and third lenses (102, 103) may have a maximum in the center and a minimum in the edge. The third gap (G3) between the third and fourth lenses (103, 104) may have a maximum in the edge and a minimum in the center. The fourth gap (G4) between the fourth and fifth lenses (105, 106) may have a maximum in the edge and a minimum in the center. The fifth gap (G5) between the fifth and sixth lenses (105, 106) may have a maximum in the center and a minimum in the edge. The sixth gap (G6) between the sixth and seventh lenses (106, 107) may have a minimum in the center and a maximum in the edge.

[0221]

[0222] Fig. 4 is a graph showing the diffraction MTF (Modulation Transfer Function) for RGB wavelengths at room temperature in the optical system of Fig. 1, and is a graph showing the luminance ratio (modulation) according to the spatial frequency. Here, the RGB wavelength can satisfy the visible light range of 435 nm to 650 nm. Fig. 5 is a graph showing the diffraction MTF (Modulation Transfer Function) for IR wavelengths at room temperature in the optical system of Fig. 1, and is a graph showing the luminance ratio (modulation) according to the spatial frequency. Here, the IR wavelength can satisfy 820 nm to 980 nm or other ranges.

[0223] Fig. 6 is a graph showing the aberration characteristics at room temperature in the optical system of Fig. 1. In the aberration graph of Fig. 6, spherical aberration (longitudinal spherical aberration), astigmatic field curves, and distortion are measured from left to right. In Fig. 6, the X-axis may represent the focal length (mm) and the degree of distortion (%), and the Y-axis may represent the height of the image. In addition, the graph for spherical aberration is a graph for light in wavelength bands of about 435 nm, about 486 nm, about 546 nm, about 587 nm, and about 656 nm, and the graphs for astigmatism and distortion are graphs for light in wavelength bands of about 546 nm. In the aberration diagram of Fig. 6, the closer each curve is to the Y-axis, the better the aberration correction function can be interpreted. It can be seen that the optical system (1000) according to the first embodiment has measured values ​​close to the Y-axis in almost all areas. That is, the optical system (1000) according to the first embodiment has improved resolution and can have good optical performance not only in the center of the field of view (FOV) but also in the periphery.

[0224] 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.

[0225]

[0226] An optical system according to a second embodiment of the invention will be described.

[0227] FIG. 7 is a side cross-sectional view of an optical system according to a second embodiment and a camera module having the same, FIG. 8 is a table showing aspherical coefficients of lenses in the optical system of FIG. 7, FIG. 9 is a table showing Sag values ​​of lens surfaces of first to seventh lenses in the optical system of FIG. 7, FIG. 10 is a graph showing data on diffraction MTF (Modulation Transfer Function) at RGB wavelengths of the optical system of FIG. 7, FIG. 11 is a graph showing data on diffraction MTF at IR wavelengths of the optical system of FIG. 7, and FIG. 12 is a graph showing data on aberration characteristics at room temperature of the optical system of FIG. 7.

[0228] Referring to FIG. 7, the optical system (1100) includes a lens unit (200), and the lens unit (200) may include a first lens (201) to a seventh lens (207). The first to seventh lenses (201 to 207) may be sequentially arranged along the optical axis (OA) of the optical system (1100). Light corresponding to information about an object may pass through the first lens (201) to the seventh lens (207) and a filter (600) and be incident on the image sensor (500).

[0229] The first lens (201) may be arranged closest to the object side. The first lens (201) may be arranged farthest from the sensor side. The first lens (201) may have negative (-) refractive power on the optical axis (OA). The first lens (201) may include a plastic material or a glass material, and may be made of glass, for example. The first lens (201) made of glass can reduce changes in the center position and radius of curvature due to temperature changes in the surrounding environment, and can protect the incident side surface of the optical system (1100).

[0230] The first surface (S1) on the object side of the first lens (201) with respect to the optical axis may be concave, and the second surface (S2) on the sensor side may be concave. The first lens (201) may have a shape in which both sides are concave. The first lens (201) is made of glass 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 and second surfaces (S1, S2) may be provided as S1 and S2 of L1 in FIG. 8.

[0231] The refractive index (n1) of the first lens (201) can satisfy the condition of n1>1.5 or n1>1.52. If the refractive index (n1) of the first lens (201) satisfies the condition, the radius of curvature of the first and second lenses (201, 202) can be increased, and lens manufacturing can be facilitated. If the refractive index (n1) of the first lens (201) is smaller than the condition, the lens surface must be formed to be sharply concave or convex in order to increase the refractive power of the first and second lenses (201, 202). In this case, lens manufacturing is not easy, the lens defect rate increases, and this may cause a decrease in yield.

[0232]

[0233] 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 positive (+) refractive power in the optical axis (OA). The second lens (202) may include a plastic or glass material. For example, the second lens (202) may be provided as a glass material.

[0234] The object-side third surface (S3) of the second lens (202) with respect to the optical axis (OA) may be convex, and the sensor-side fourth surface (S4) may be convex. The second lens (202) may have a convex shape on both sides. The second lens (202) may be made of glass 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 and fourth surfaces (S3, S4) may be provided as S1 and S2 of L2 in FIG. 8.

[0235] The third surface (S3) of the second lens (202) may have a critical point from the optical axis (OA) to the end of the effective area. When the third surface (S3) has a critical point, it may be located in a range of 65% to 85%, preferably in a range of 70% to 80%, of the effective radius (r42) from the optical axis (OA). The critical point of the fourth surface (S4) may be located in a range of 1 mm to 1.8 mm, preferably in a range of 1 mm to 1.4 mm from the optical axis (OA).

[0236] The critical point of the third surface (S3) is a point where the sign of the slope value with respect to the optical axis (OA) and the direction perpendicular to the optical axis (OA) changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the slope value is 0. In addition, the critical point of the third surface (S3) may be a point where the slope value of the tangent line passing through the lens surface increases and then decreases, or a point where the slope value decreases and then increases. The fourth surface (S4) of the second lens (202) may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0237]

[0238] The third lens (203) may be arranged third from the object side. The third lens (203) may be arranged 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 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 as a glass material.

[0239] The fifth surface (S5) on the object side of the third lens (203) with respect to the optical axis may be concave, and the sixth surface (S6) on the sensor side may be convex. The third lens (203) may have a meniscus shape in which the sensor side is convex. The third lens (203) may have a meniscus shape in which the object side is concave. The third lens (203) is 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 provided without a critical point from the optical axis (OA) to the end of the effective area.

[0240] The aperture (Stop) may be arranged around the sensor-side fourth surface (S4) of the second lens (202). The aperture (Stop) may be arranged around the object-side fifth surface (S5) of the third lens (203). The aperture can reduce the TTL within the field of view range, enabling miniaturization of the optical system. Accordingly, a decrease in the yield by weight of the optical system can be prevented, and production efficiency can be improved. In addition, the optical system can be miniaturized by reducing the TTL at a horizontal field of view (FOV_H) of 125 degrees to 135 degrees.

[0241]

[0242] The fourth lens (204) may be arranged fourth from the object side. The fourth lens (204) may be arranged fourth from 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 positive (+) or negative (-) refractive power on the optical axis (OA). The fourth lens (204) may have positive (+) refractive power. The fourth lens (204) may include a plastic or glass material. For example, the fourth lens (204) may be provided as a glass material.

[0243] The object-side seventh surface (S7) of the fourth lens (204) with respect to the optical axis may be convex, and the sensor-side eighth surface (S8) may be convex. The fourth lens (204) may have a convex shape on both sides. The fourth lens (204) may be made of glass and may be spherical. At least one or both of the seventh surface (S7) and the eighth surface (S9) may be spherical. The aspherical coefficients of the seventh and eighth surfaces (S7, S8) may be provided as S1 and S2 of L4 in FIG. 8. At least one or both of the seventh surface (S7) and the eighth surface (S8) may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0244]

[0245] The fifth lens (205) may be arranged as the fifth lens from the object side. The fifth lens (205) may be arranged as the third lens 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 positive (+) or negative (-) refractive power on the optical axis (OA). The fifth lens (205) may have negative (-) refractive power. The fifth lens (205) may include a plastic or glass material. For example, the fifth lens (205) may be provided as a glass material.

[0246] With respect to the optical axis (OA), the ninth surface (S9) on the object side of the fifth lens (205) may be concave, and the tenth surface (S10) on the sensor side may be concave. The fifth lens (205) may have a shape in which both sides are concave with respect to the optical axis (OA). The fifth lens (205) may be made of glass and may be aspherical. At least one or both of the ninth surface (S9) and the tenth surface (S10) may be aspherical. Aspheric coefficients of the ninth and tenth surfaces (S9, S10) may be provided as S1 and S2 of L5 in FIG. 8. At least one or both of the ninth surface (S9) and the tenth surface (S10) may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0247]

[0248] The sixth lens (206) may be arranged as the sixth lens from the object side. The sixth lens (206) may be arranged as the second lens 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 positive (+) or negative (-) refractive power on the optical axis (OA). The sixth lens (206) may have positive (+) refractive power. The sixth lens (206) may include a plastic or glass material. For example, the sixth lens (206) may be provided as a glass material.

[0249] The sixth lens (206) may have a convex shape on the object-side eleventh surface (S11) and a convex shape on the sensor-side twelveth surface (S12) with respect to the optical axis (OA). The sixth lens (206) may have a convex shape on both sides with respect to the optical axis (OA). At least one or both of the eleventh surface (S11) and the twelfth surface (S12) may be aspherical. The aspherical coefficients of the eleventh and twelfth surfaces (S11, S12) may be provided as S1 and S2 of L6 in FIG. 8.

[0250] The eleventh surface (S11) of the sixth lens (206) may have a critical point from the optical axis (OA) to the end of the effective area. When the eleventh surface (S11) has a critical point, it may be located in a range of 80% to 95%, preferably 90% to 95%, of the effective radius (r62) from the optical axis (OA). The critical point of the eleventh surface (S11) may be located in a range of 1.5 mm to 2.4 mm, preferably 2 mm to 2.4 mm, from the optical axis (OA). The twelfth surface (S12) of the sixth lens (206) may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0251]

[0252] 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 positive (+) or negative (-) refractive power on the optical axis (OA). The seventh lens (207) may have negative (-) refractive power. The seventh lens (207) may include a plastic or glass material. For example, the seventh lens (207) may be made of glass.

[0253] The object-side 13th surface (S13) of the seventh lens (207) on the optical axis may be concave, and the sensor-side 14th surface (S14) may be concave. The seventh lens (207) may have a concave shape on both sides. The seventh lens (207) may be made of glass and may be aspherical. At least one or both of the 13th surface (S13) and the 14th surface (S14) may be aspherical. The aspherical coefficients of the 13th and 14th surfaces (S13, S14) may be provided as S1 and S2 of L7 in FIG. 8.

[0254] The 13th surface (S13) of the seventh lens (207) may be provided without a critical point from the optical axis (OA) to the end of the effective area. The 14th surface (S14) of the seventh lens (207) may have a critical point from the optical axis (OA) to the end of the effective area. When the 14th surface (S14) has a critical point, it may be located in a range of 50% to 70%, preferably in a range of 60% to 65%, of the effective radius (r72) from the optical axis (OA). The critical point of the 14th surface (S14) may be located in a range of 1.5 mm to 2.5 mm, preferably in a range of 1.8 mm to 2.2 mm from the optical axis (OA).

[0255] The critical point of the 14th surface (S14) is a point where the sign of the slope value with respect to the optical axis (OA) and the direction perpendicular to the optical axis (OA) changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the slope value is 0. In addition, the critical point of the 14th surface (S14) may be a point where the slope value of the tangent line passing through the lens surface increases and then decreases, or a point where the slope value decreases and then increases.

[0256]

[0257] LensSurfaceRadiusThicknessndvdSemiApertureFocal length1S1-86.0510.7001.5455.583.690-3.852 S22.1341.316 1.927 2S39.4671.5001.8936.711.7905.379 S4-9.1080.679 1.600 3S5(Stop)-6.7540.6461.7650.281.0417.652 S6-3.2740.050 1.200 4S75.3831.0531.7354.671.4503.063 S8-3.5270.050 1.530 5S9-6.0890.4001.9021.441.488-2.800 S104.4840.847 1.653 6S117.5001.3711.8046.502.5183.421 S12-4.0220.082 2.836 7S13-3.5760.4221.6137.772.939-3.803 S146.9990.187 3.238 FilterS15Infinity0.900 3.326Infinity S16Infinity0.700 3.466 Image Infinity 3.656

[0258] Table 3 shows the surface number (Surface), radius of curvature (Radius), center thickness of each lens or distance between lens surfaces (Thickness), refractive index (Index,nd), Abbe number (Abbe,vd), effective radius (Semi Aperture), and focal length (Fcoal length) of the lens according to the second embodiment of the present invention. At this time, the unit of the radius of curvature and thickness or distance may be mm.

[0259]

[0260] Item ValueItem ValueF3.004ET11.408ΣIndex12.232ET21.353ΣAbbe302.947ET30.507ΣCT6.570 ET40.446ΣCG3.023ET50.996CA_max7.379ET60.562CA_min2.083ET70.724CA_Ave r4.629F-number2.200CT_max1.500FOV_D129.000CT_min0.400FOV_V84.000CT_Aver0.939FOV_H107.000EPD1.366ImgH7.313BFL1.787SD5.107TD9.302TTL10.902

[0261] Table 4 shows the items of the mathematical formulas described above in the optical system (1100) of the embodiment, including the total track length (TTL) (mm), back focal length (BFL), effective focal length (F) (mm), ImgH (mm), effective diameter (CA) (mm), thickness (mm), TTL (mm), the optical axis distance from the first surface (S1) to the fourteenth surface (S14) TD (mm), the optical axis distance from the stop (Stop) to the fourteenth surface (S14) SD (mm), the sum of refractive indices, the sum of Abbe numbers, the sum of thicknesses (mm), the sum of spacings between adjacent lenses, the effective diameter characteristic, the diagonal angle of view (FOV_D) (Degree), the vertical angle of view (FOV_V) (Degree), the horizontal angle of view (FOV_H) (Degree), the edge thickness (ET), the F number, etc. of the optical system (1100).

[0262]

[0263] The center thicknesses of the first to seventh lenses (201 to 207) are represented by CT1 to CT7, the edge thicknesses at the ends of the effective areas of each lens are represented by ET1 to ET7, the center gap between two adjacent lenses is represented by CG1 to CG6, and the edge gaps between the edges of each lens are represented by EG1 to EG6. The BFL (Back focal length) is the optical axis distance from the image sensor (500) to the center of the last lens. The TTL is the optical axis distance from the center of the first surface (S1) of the first lens (201) to the upper surface of the image sensor (500).

[0264] As shown in Fig. 8, among the lenses of the lens unit (200) of the second embodiment, the lens surfaces of the first, second, third, fourth, fifth, sixth, and seventh lenses (201, 202, 203, 204, 205, 206, and 207) may include aspherical surfaces having a 30th-order aspherical surface coefficient. For example, the first, second, third, fourth, fifth, sixth, and seventh lenses (201, 202, 203, 204, 205, 206, and 207) may include lens surfaces having a 30th-order aspherical surface coefficient. As described above, the aspherical surface having a 30th-order aspherical surface coefficient (a value other than "0") can significantly change the aspherical shape of the peripheral portion, and thus can effectively correct the optical performance of the peripheral portion of the field of view (FOV).

[0265] When comparing the absolute values ​​of the curvature radii of each lens, the curvature radii of the first surface (S1) of the first lens (201) on the optical axis (OA) may be the largest among the lenses, and the curvature radii of the second surface (S2) of the first lens (201) may be the smallest among the lenses. The difference between the maximum curvature radii and the minimum curvature radii may be 30 times or more, for example, 35 times to 45 times.

[0266] Among the lenses, there may be 12 or more and 14 or fewer surfaces with an absolute value of curvature radius of 10 mm or less on the object side and sensor side. The sensor side (second surface (S2)) of the first lens (201), the object side (third surface (S3)) of the second lens (202), the sensor side (fourth surface (S4)) of the second lens (202), the object side (fifth surface (S5)) of the third lens (203), the sensor side (sixth surface (S6)) of the third lens (203), the object side (seventh surface (S7)) of the fourth lens (204), the sensor side (eighth surface (S8)) of the fourth lens (204), the object side (ninth surface (S9)) of the fifth lens (205), the sensor side (tenth surface (S10)) of the fifth lens (205), the object side (eleventh surface (S11)) of the sixth lens (206), the sensor side (twelfth surface (S12)) of the sixth lens (206), The radius of curvature of the object side (13th surface (S13)) of the 7th lens (207) and the sensor side (14th surface (S14)) of the 7th lens (207) may have an absolute value of 10 mm or less.

[0267] Among the lenses, there may be at least one and no more than two surfaces having an absolute value of curvature radius of 80 mm or more on the object side and the sensor side. The absolute value of the curvature radius of the object side (first surface (S1)) of the first lens (201) may be at least 80 mm.

[0268] The shape of the first lens (201) having a spherical shape can be designed to be gentle. If the aspherical surface is positioned at the frontmost part of the optical system (1100), the performance of the lens is improved, but the assemblability may be reduced. To improve the assemblability, the shape of the first lens (201) must be designed to be gentle. In order to minimize the influence on the lens placed on the sensor side when assembling the lens into the barrel, the first lens (201) can be designed to have almost no curvature.

[0269] The absolute value of the curvature radius of the first surface (S1) of the first lens (201) may be greater than the absolute value of the curvature radius of the second surface (S2). The absolute value of the curvature radius of the third surface (S3) of the second lens (202) may be greater than the absolute value of the curvature radius of the fourth surface (S4). The absolute value of the curvature radius of the fifth surface (S5) of the third lens (203) may be greater than the absolute value of the curvature radius of the sixth surface (S6). The absolute value of the curvature radius of the seventh surface (S7) of the fourth lens (204) may be greater than the absolute value of the curvature radius of the eighth surface (S8). The absolute value of the curvature radius of the ninth surface (S9) of the fifth lens (205) may be greater than the absolute value of the curvature radius of the tenth surface (S10). The absolute value of the radius of curvature of the eleventh surface (S11) of the sixth lens (206) may be greater than the absolute value of the radius of curvature of the twelfth surface (S12). The absolute value of the radius of curvature of the thirteenth surface (S13) of the seventh lens (207) may be less than the absolute value of the radius of curvature of the fourteenth surface (S14).

[0270] The ratio of the radius of curvature of each lens can satisfy the following conditions.

[0271] Condition 1: 30 < |L1R1 / L1R2| < 50

[0272] Condition 2: 1 < |L2R1 / L2R2| < 5

[0273] Condition 3: 1 < |L3R1 / L3R2| < 5

[0274] Condition 4: 1 < |L4R1 / L4R2| < 5

[0275] Condition 5: 1 < |L5R1 / L5R2| < 5

[0276] Condition 6: 1 < |L6R1 / L6R2| < 5

[0277] Condition 7: 0.1 < |L7R1 / L7R2| < 1

[0278]

[0279] When describing the central thickness of the lenses based on the optical axis, the central thickness (CT2) of the second lens (202) is the largest among the lenses, and the central thickness (CT5) of the fifth lens (205) is the smallest among the lenses. The difference between the maximum and minimum central thicknesses among the lenses may be in the range of 1 mm or more and 3 mm or less.

[0280] The central thickness of each lens may satisfy any one of the following conditions:

[0281] Condition 1: CT2, CT4, CT6, CT7 > CT1 > CT3, CT5

[0282] Condition 2: CT2 > CT1, CT3, CT4, CT5, CT6, CT7

[0283] Condition 3: CT1, CT2, CT4, CT6, CT7 > CT3 > CT5

[0284] Condition 4: CT2, CT6 > CT4 > CT1, CT3, CT5, CT7

[0285] Condition 5: CT1, CT2, CT3, CT4, CT6, CT7 > CT5

[0286] Condition 6: CT2 > CT6 > CT1, CT3, CT4, CT5, CT7

[0287] Condition 7: CT2, CT4, CT6 > CT7 > CT1, CT3, CT5

[0288]

[0289] When describing the center spacing (CG) between the lenses, the center spacing (CG1) between the first lens (201) and the second lens (202) may be maximum, the center spacing (CG3) between the third and fourth lenses (203, 204) and the center spacing (CG4) between the fourth and fifth lenses (204, 205) may be minimum. The difference between the maximum center spacing and the minimum center spacing among the spaced lens spacings may be 1.0 mm or more, for example, in the range of 1.0 mm to 1.5 mm.

[0290] The center spacing between each lens can satisfy the conditions below.

[0291] Condition 1: CG1 > CG2, CG3, CG4, CG5, CG6

[0292] Condition 2: CG1, CG5 > CG2 > CG3, CG4, CG6

[0293] Condition 3: CG1, CG2, CG5, CG6 > CG3 = CG4

[0294] Condition 4: CG1 > CG5 > CG2, CG3, CG4, CG6

[0295] Condition 5: CG1, CG2, CG5 > CG6 > CG3, CG4

[0296]

[0297] Regarding the effective diameter, the lens having the maximum effective diameter may be placed between the first lens (201) closest to the object and the seventh lens (207) closest to the image sensor (500). The lens having the maximum effective diameter may be a glass lens. The lens having the maximum effective diameter may be the seventh lens (207). Here, the effective diameter is the average of the effective diameters on the object-side surface and the sensor-side surface of each lens. The lens surface having the maximum effective diameter may be the first surface (S1) of the first lens (201).

[0298] The lens having the minimum effective diameter may be any one of the glass material lenses, and for example, the effective diameter of the third lens (203) may be the minimum within the lens unit (200). The lens surface having the minimum effective diameter may be the fifth surface (S5) of the third lens (203).

[0299] The effective diameter of each lens can satisfy any one of the conditions below.

[0300] Condition 1: CA_L7 > CA_L1 > CA_L2, CA_L3, CA_L4, CA_L5, CA_L6

[0301] Condition 2: CA_L1, CA_L6, CA_L7 > CA_L2 > CA_L3, CA_L4, CA_L5

[0302] Condition 3: CA_L1, CA_L2, CA_L4, CA_L5, CA_L6, CA_L7 > CA_L3

[0303] Condition 4: CA_L1, CA_L2, CA_L5, CA_L6, CA_L7 > CA_L4 > CA_L3

[0304] Condition 5: CA_L1, CA_L2, CA_L6, CA_L7 > CA_L5 > CA_L3, CA_L4

[0305] Condition 6: CA_L1, CA_L7 > CA_L6 > CA_L2, CA_L3, CA_L4, CA_L5

[0306] Condition 7: CA_L7 > CA_L1, CA_L2, CA_L3, CA_L4, CA_L5, CA_L6

[0307]

[0308] Regarding the refractive index, the refractive index of the fifth lens (205) may be the highest among the lenses and may be greater than 1.5, for example, greater than 1.8. The first lens (201) may have the lowest refractive index among the lenses. For example, the refractive index of the first lens (201) may be the lowest among the lenses and 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 0.3 or more.

[0309] The refractive index of each lens can satisfy any of the conditions below.

[0310] Condition 1: n2, n3, n4, n5, n6, n7 > n1

[0311] Condition 2: n5 > n2 > n1, n3, n4, n6, n7

[0312] Condition 3: n2, n5, n6 > n3 > n1, n4, n7

[0313] Condition 4: n2, n3, n5, n6 > n4 > n1, n7

[0314] Condition 5: n5 > n1, n2, n3, n4, n6, n7

[0315] Condition 5: n2, n5 > n6 > n1, n3, n4, n7

[0316] Condition 6: n2, n3, n4, n5, n6 > n7 > n1

[0317]

[0318] Comparing the Abbe numbers, the Abbe number of the first lens (201) is the largest among the lenses and may be 50 or more. The Abbe number of the fifth lens (205) is the smallest among the lenses and may be 25 or less. The difference between the maximum Abbe number and the minimum Abbe number may be 30 or more. By providing the Abbe number of the first lens (201) as the largest and the Abbe number of the fifth lens (205) as the smallest, the chromatic dispersion of light traveling between the lenses made of glass can be controlled, and the chromatic dispersion between the lenses can be increased to guide it to the image sensor (500).

[0319] The Abbe number of each lens can satisfy any of the conditions below.

[0320] Condition 1: v1 > v2, v3, v4, v5, v6, v7

[0321] Condition 2: v1, v3, v4, v6, v7 > v2 > v5

[0322] Condition 3: v1, v4 > v3 > v2, v5, v6, v7

[0323] Condition 4: v1 > v4 > v2, v3, v5, v6, v7

[0324] Condition 5: v1, v2, v3, v4, v6, v7 > v5

[0325] Condition 6: v1, v3, v4 > v6 > v2, v5, v7

[0326] Condition 7: v1, v3, v4, v6 > v7 > v2, v5

[0327]

[0328] The focal lengths (F1, F5, F7) of the first, fifth, and seventh lenses (201, 205, and 207) may have negative (-) signs. The first, fifth, and seventh lenses (201, 205, and 207) may have negative (-) refractive power. The focal lengths (F2, F3, F4, F6) of the second, third, fourth, and sixth lenses (202, 203, 204, and 206) may have positive (+) signs. The second, third, and fourth lenses (202, 203, 204, and 206) may have positive (+) refractive power. The second, third, and fourth lenses (202, 203, and 204) having positive (+) refractive power may be arranged on the sensor side of the first lens (201) having negative (-) refractive power. Through this, light incident from the object side can move away from the optical axis direction and then gather again in the optical axis direction, thereby forming a stable optical path.

[0329]

[0330] Additionally, the fourth lens (204) and the fifth lens (205), which are adjacently arranged lenses, can satisfy the following conditions.

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

[0332] Condition 2: Dispersion of a lens with positive refractive power > Dispersion of a lens with negative refractive power

[0333] Here, among the glass lenses, the fourth lens (204) has negative refractive power and the fifth lens (205) has positive refractive power, so according to conditions 1 and 2, the refractive index of the fourth lens (204) is smaller than the refractive index of the fifth lens (205), and the dispersion value of the fourth lens (204) is larger than the dispersion value of the fifth lens (205). Chromatic aberration occurring in a glass lens can be corrected by a glass lens. In addition, since the fourth lens (204) and the fifth lens (205), which are glass lenses arranged in succession, satisfy the conditions of a refractive index difference of 0.01 or more and 0.1 or less and an Abbe number difference of 20 or more and 50 or less, chromatic aberration occurring in a glass lens can be compensated for by a glass lens.

[0334] Optical systems suffer from chromatic aberration, and this is corrected by using cemented lenses or two lenses arranged in series. As temperatures change from low to high, the lenses contract and expand repeatedly. Since lenses made of the same material exhibit the same change in lens characteristics with temperature changes, it is effective to correct chromatic aberration between lenses made of the same material even when the temperature changes. Therefore, in the second embodiment of the present invention, the fourth lens (204) and the fifth lens (205) are used to correct chromatic aberration occurring in a glass lens.

[0335]

[0336] When comparing the focal lengths in absolute values, the focal length of the third lens (203) is the largest among the lenses, and may be 5 or more and 10 or less. Among the lenses, the third lens (203) made of glass may have the largest focal length and the smallest refractive power. The focal length of the fifth lens (205) is the smallest among the lenses, and the absolute value of the focal length of the fifth lens (205) may be 1 or more and 3 or less. Among the lenses, the fifth lens (205) made of glass may have the smallest focal length and the largest refractive power.

[0337] Among the lenses, the lens having the minimum focal length may be the fifth lens (205). The difference between the maximum focal length and the minimum focal length may be 3 or more or 4 or more. Accordingly, the optical system may have improved MTF characteristics, aberration control characteristics, resolution characteristics, etc. within the set field of view range, and may have good optical performance in the periphery of the field of view.

[0338] The absolute value of the focal length of each lens can satisfy any of the conditions below.

[0339] Condition 1: |f2|, |f3| > |f1| > |f4|, |f5|, |f6|, |f7|

[0340] Condition 2: |f3| > |f2| > |f1|, |f4|, |f5|, |f6|, |f7|

[0341] Condition 3: |f3| > |f1|, |f2|, |f4|, |f5|, |f6|, |f7|

[0342] Condition 4: |f1|, |f2|, |f3|, |f6|, |f7| > |f4| > |f5|

[0343] Condition 5: |f1|, |f2|, |f3|, |f4|, |f6|, |f7| > |f5|

[0344] Condition 6: |f1|, |f2|, |f3|, |f7| > |f6| > |f4|, |f5|

[0345] Condition 7: |f1|, |f2|, |f3| > |f7| > |f4|, |f5|, |f6|

[0346]

[0347] The thickness (T1) of the first lens (201) may be maximum at the edge and minimum at the center, and the maximum thickness is in the range of 2 to 2.5 times the minimum thickness. The thickness (T2) of the second lens (202) may be minimum at the edge and maximum at the center, and the maximum thickness is in the range of 1 to 1.5 times the minimum thickness. The thickness (T3) of the third lens (203) may be maximum at the center and minimum at the edge, and the maximum thickness is in the range of 1.2 to 1.5 times the minimum thickness. The thickness (T4) of the fourth lens (204) may be maximum at the center and minimum at the edge, and the maximum thickness is in the range of 2 to 2.5 times the minimum thickness. The thickness (T5) of the fifth lens (205) may be minimum at the center and maximum at the edge, and the maximum thickness is in the range of 2 to 2.5 times the minimum thickness. The thickness (T6) of the sixth lens (206) may be maximum at the center and minimum at the edge, and the maximum thickness is in the range of 2 to 2.5 times the minimum thickness. The thickness (T7) of the seventh lens (207) may be maximum at the center and minimum at the edge, and the maximum thickness is in the range of 1.2 to 1.5 times the minimum thickness.

[0348] The thickness of each lens can satisfy any of the conditions below.

[0349] Condition 1: 0.2 < CT1 / ET1 < 1, 2 < ET1 / CT1 < 2.5

[0350] Condition 2: 1 < CT2 / ET2 < 1.5, 0.5 < ET2 / CT2 < 1

[0351] Condition 3: 1 < CT3 / ET3 < 1.5, 0.5 < ET3 / CT3 < 1

[0352] Condition 4: 2 < CT4 / ET4 < 2.5, 0.2 < ET4 / CT4 < 1

[0353] Condition 5: 0.1 < CT5 / ET5 < 0.5, 2 < ET5 / CT5 < 2.5

[0354] Condition 6: 2 < CT6 / ET6 < 2.5, 0.1 < ET6 / CT6 < 0.5

[0355] Condition 7: 1 < CT7 / ET7 < 1.5, 0.5 < ET7 / CT7 < 1

[0356] Condition 8: 1 < ΣCT / ΣET < 1.5, 0.5 < ΣET / ΣCT < 1

[0357]

[0358] Among the gaps (G1-G6) between the lenses, the first gap (G1) between the first and second lenses (201, 202) may have a maximum in the center and a minimum in the edge. The second gap (G2) between the second and third lenses (202, 203) may have a minimum in the center and a maximum in the edge. The third gap (G3) between the third and fourth lenses (203, 204) may have a maximum in the edge and a minimum in the center. The fourth gap (G4) between the fourth and fifth lenses (205, 206) may have a maximum in the edge and a minimum in the center. The fifth gap (G5) between the fifth and sixth lenses (205, 206) may have a maximum in the center and a minimum in the edge. The sixth gap (G6) between the sixth and seventh lenses (206, 207) may have a minimum in the center and a maximum in the edge.

[0359]

[0360] Fig. 10 is a graph showing the diffraction MTF (Modulation Transfer Function) for RGB wavelengths at room temperature in the optical system of Fig. 7, and is a graph showing the luminance ratio (modulation) according to the spatial frequency. Here, the RGB wavelength can satisfy the visible light range of 435 nm to 650 nm. Fig. 11 is a graph showing the diffraction MTF (Modulation Transfer Function) for IR wavelengths at room temperature in the optical system of Fig. 7, and is a graph showing the luminance ratio (modulation) according to the spatial frequency. Here, the IR wavelength can satisfy 820 nm to 980 nm or other ranges.

[0361] Fig. 12 is a graph showing the aberration characteristics at room temperature in the optical system of Fig. 7. In the aberration graph of Fig. 12, spherical aberration (longitudinal spherical aberration), astigmatic field curves, and distortion are measured from left to right. In Fig. 12, the X-axis may represent the focal length (mm) and the degree of distortion (%), and the Y-axis may represent the height of the image. In addition, the graph for spherical aberration is a graph for light in wavelength bands of about 435 nm, about 486 nm, about 546 nm, about 587 nm, and about 656 nm, and the graphs for astigmatism and distortion are graphs for light in wavelength bands of about 546 nm. In the aberration diagram of Fig. 12, the closer each curve is to the Y-axis, the better the aberration correction function can be interpreted. It can be seen that the optical system (1100) according to the second embodiment has measured values ​​close to the Y-axis in almost all areas. In other words, the optical system (1100) according to the second 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.

[0362] 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 at the center of the field of view (FOV) but also at the periphery.

[0363]

[0364] The optical systems (1000, 1100) according to the first and second embodiments disclosed above can satisfy at least one or two or more of the mathematical equations described below. Accordingly, the optical systems (1000, 1100) according to the first and second embodiments can have improved optical characteristics. For example, when the optical system (1000, 1100) satisfies at least one mathematical equation, the optical system (1000, 1100) can effectively control aberration characteristics such as chromatic aberration and distortion aberration, and can have good optical performance not only at the center but also at the periphery of the field of view (FOV). In addition, the optical system (1000, 1100) can have improved resolution. In addition, the thickness of the lens on the optical axis (OA) described in the mathematical equations and the spacing between adjacent lenses on the optical axis (OA) can refer to the first and second embodiments disclosed above.

[0365]

[0366] The optical systems (1000, 1100) according to the first and second embodiments disclosed above can satisfy at least one or two or more of the mathematical equations described below. Accordingly, the optical systems (1000, 1100) according to the first and second embodiments can have improved optical characteristics. For example, when the optical system (1000, 1100) satisfies at least one mathematical equation, the optical system (1000, 1100) can effectively control aberration characteristics such as chromatic aberration and distortion aberration, and can have good optical performance not only at the center but also at the periphery of the field of view (FOV). In addition, the optical system (1000, 1100) can have improved resolution. In addition, the thickness of the lens on the optical axis (OA) described in the mathematical equations and the spacing between adjacent lenses on the optical axis (OA) can refer to the first and second embodiments disclosed above.

[0367]

[0368] [Mathematical Formula 1]

[0369] 0.1 < F / TTL < 0.3

[0370] In mathematical expression 1, F is the effective focal length of the optical system, 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 (101, 201) to the upper surface of the image sensor (500). Accordingly, an optical system for a driver assistance system can be provided. When the optical system (1000, 1100) according to the embodiment satisfies mathematical expression 1, the optical system (1000, 1100) can have an appropriate focal length in the set TTL range, and provides an optical system that can form an image while maintaining an appropriate focal length even in RGB wavelengths and IR wavelengths. When it is less than the lower limit of mathematical expression 1, the refractive power of the lenses needs to be increased, making it difficult to correct spherical aberration or distortion aberration, and when it exceeds the upper limit of mathematical expression 1, the effective diameter or TTL of the lenses may become long, which may cause a problem in that the imaging lens system becomes large. In the first and second embodiments, mathematical expression 1 can preferably satisfy 0.2 < F / TTL < 0.3.

[0371]

[0372] [Equation 2]

[0373] 1 < TTL / ImgH < 2

[0374] In mathematical expression 2, TTL (Total track length) means the distance (mm) from the vertex of the first surface (S1) of the first lens (101, 201) to the upper surface of the image sensor (500) on the optical axis (OA), and ImgH means the maximum diagonal length of the image sensor (500). When mathematical expression 2 is satisfied, the optical system (1000, 1100) can have TTL for application to the vehicle image sensor (500), and can provide more improved image quality. When it is less than the lower limit of mathematical expression 2, the refractive power of the lenses needs to be increased, making it difficult to correct spherical aberration or distortion aberration, and when it is more than the upper limit of mathematical expression 2, the effective diameter or TTL of the lenses becomes long, which may cause a problem of the imaging lens system becoming larger. In the first and second embodiments, mathematical expression 2 can preferably satisfy 1.3 < TTL / ImgH < 1.7.

[0375]

[0376] [Equation 3]

[0377] 1 < |F1| / F < 2

[0378] In mathematical expression 3, F1 is the focal length of the first lens (101, 201), and F is the effective focal length of the optical system. When mathematical expression 3 is satisfied, the optical system (1000, 1100) can have a set angle of view and an appropriate focal length, and a vehicle optical system can be provided. In addition, the angle of view can be set to be large in an appropriate TTL range through the first lens (101, 201) having negative (-) refractive power. When it is below the lower limit of mathematical expression 3, the effective diameter or TTL of the lenses may become long, which may cause a problem in that the imaging lens system becomes large. When it is above the upper limit of mathematical expression 3, the influence of the first lens (101, 201) on the entire optical system becomes small, and the refractive power of the lenses needs to be increased, which causes a problem in that correction of spherical aberration or distortion aberration becomes difficult. In the first and second embodiments, mathematical expression 3 preferably satisfies 1.1 < |F1| / F < 1.5 can be satisfied.

[0379]

[0380] [Equation 4]

[0381] 1.5 < F2 / F < 3

[0382] In mathematical expression 4, F2 is the focal length of the second lens (102, 202), and F is the effective focal length of the optical system. When mathematical expression 4 is satisfied, the optical system (1000, 1100) can have a set angle of view and an appropriate focal length, and an optical system for a vehicle can be provided. When it is less than the lower limit of mathematical expression 4, the effective diameter or TTL of the lenses may become long, which may cause a problem in that the imaging lens system becomes large. When it is more than the upper limit of mathematical expression 4, the influence of the second lens (102, 202) in the entire optical system becomes small, and the refractive power of the lenses needs to be increased, which causes a problem in that correction of spherical aberration or distortion aberration becomes difficult. In the first and second embodiments, mathematical expression 4 may preferably satisfy 1.7 < F2 / F < 3.

[0383]

[0384] [Equation 5]

[0385] 0.01 < CT4 / F < 0.05

[0386] In mathematical expression 5, CT4 is the central thickness of the fourth lens (104, 204), and F is the effective focal length of the optical system. When mathematical expression 5 is satisfied, the optical system (1000, 1100) can have a set angle of view and an appropriate focal length, and an optical system for a vehicle can be provided. In addition, by setting the fourth lens (104, 204) located at the center of the optical system (1000, 1100) to an appropriate thickness, an optical system is provided that can maintain an appropriate focal length and form an image even in RGB wavelengths and IR wavelengths. In the first and second embodiments, mathematical expression 5 can preferably satisfy 0.01 < CT4 / F < 0.03.

[0387]

[0388] [Equation 6]

[0389] 0.01 < CT6 / F < 0.05

[0390] In mathematical expression 6, CT6 is the central thickness of the sixth lens (106, 206), and F is the effective focal length of the optical system. When mathematical expression 6 is satisfied, the optical system (1000, 1100) can have a set angle of view and an appropriate focal length, and an optical system for a vehicle can be provided. In addition, by setting the sixth lens (106, 206) arranged adjacent to the image sensor (500) to an appropriate thickness, an optical system is provided that can maintain an appropriate focal length and form an image even in RGB wavelengths and IR wavelengths. In the first and second embodiments, mathematical expression 6 can preferably satisfy 0.01 < CT6 / F < 0.03.

[0391]

[0392] [Equation 7]

[0393] Number of inflection points in L7 > 0

[0394] Mathematical expression 7 means that there is an inflection point on the object side or sensor side of the seventh lens (107, 207). The sensor side (the 14th surface (S14)) of the seventh lens (107, 207) can have one inflection point. By forming an inflection point on the seventh lens (107, 207), which is the lens closest to the image sensor (500), spherical aberration or distortion aberration can be corrected.

[0395]

[0396] [Equation 8]

[0397] Focus deviation < 20um in RGB and IR wavelengths

[0398] Mathematical expression 8 satisfies the requirement that the focus deviation is less than 20 μm in the RGB wavelength (visible light range) of 435 nm to 650 nm and the IR wavelength of 820 nm to 980 nm, or in other regions, the optical system can reliably receive light in various environments. For example, optical characteristics can be stably guaranteed in various environments such as nighttime environments, vehicle exterior environments, and driver surveillance environments.

[0399]

[0400] [Equation 9]

[0401] 2 < F / EPD < 3

[0402] In mathematical expression 9, F represents the effective focal length of the optical system, and EPD represents the diameter of the entrance pupil (effective aperture). When mathematical expression 9 is satisfied, an image with a brightness suitable for driver monitoring can be provided, and a large amount of light can be received by the image sensor. In the first and second embodiments, mathematical expression 9 preferably satisfies 2 < F / EPD < 2.5.

[0403]

[0404] [Equation 10]

[0405] 0.1 < BFL / TTL < 0.3

[0406] In mathematical expression 10, BFL means the optical axis distance from the image sensor (500) to the center of the sensor side of the last lens, 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 (101, 201) to the upper surface of the image sensor (500). When mathematical expression 10 is satisfied, the optical system (1000, 1100) can have a set angle of view and an appropriate focal length, and an optical system for a vehicle can be provided. In addition, the optical system (1000, 1100) can minimize the gap between the last lens and the image sensor (500), and thus can have good optical characteristics at the periphery of the field of view (FOV). In the first and second embodiments, mathematical expression 10 can preferably satisfy 0.1 < BFL / TTL < 0.2.

[0407]

[0408] [Equation 11]

[0409] 1.6 < n4,n5,n6,n7 < 1.95

[0410] In mathematical expression 11, n4 is the refractive index of the fourth lens (104, 204), n5 is the refractive index of the fifth lens (105, 205), n6 is the refractive index of the sixth lens (106, 206), and n7 is the refractive index of the seventh lens (107, 207). The fourth to seventh lenses (104-107, 204-207) are made of glass injection mold (GIM) material, so that the refractive index can be designed in various ways like glass material, and can be transformed into various aspherical shapes like plastic material.

[0411]

[0412] [Equation 12]

[0413] 1.8 < (CAL6S1-CAL5S2) / CG5 < 2.2

[0414] In mathematical expression 12, CA_L6S1 is the effective diameter of the object-side surface (the eleventh surface (S11)) of the sixth lens (106, 206), CA_L5S2 is the effective diameter of the sensor-side surface (the tenth surface (S10)) of the fifth lens (105, 205), and CG5 is the gap between the fifth lens (105, 205) and the sixth lens (106, 206). When mathematical expression 12 is satisfied, the light path passing through the fifth lens (105, 205) and the sixth lens (106, 206), which have a large difference in effective diameters, can be controlled, and good optical characteristics can be obtained at the periphery of the field of view (FOV). In the first and second embodiments, mathematical expression 12 can preferably satisfy 1.9 < (CAL6S1-CAL5S2) / CG5 < 2.1.

[0415]

[0416] [Equation 13]

[0417] 1 < |F4 / F5| < 2

[0418] In mathematical expression 13, F4 is the focal length of the fourth lens (104, 204), and F5 is the focal length of the fifth lens (105, 205). When mathematical expression 13 is satisfied, the optical system (1000, 1100) can have a set angle of view and an appropriate focal length, and an optical system for a vehicle can be provided. The fourth lens (104, 204) and the fifth lens (105, 205) adjacently arranged in the optical system (1000, 1100) can correct aberrations, and can be lenses with a large refractive power among the lenses of the optical system (1000, 1100). In the first and second embodiments, mathematical expression 13 can preferably satisfy 1 < |F4 / F5| < 1.5.

[0419]

[0420] [Equation 14]

[0421] 0.5 < ET7 / CT7 < 1

[0422] In mathematical expression 14, ET7 is the edge thickness of the seventh lens (107, 207), and CT7 is the center thickness of the seventh lens (107, 207). The ratio of the edge thickness to the center thickness may be referred to as a thickness ratio. When mathematical expression 14 is satisfied, even if the center thickness of the seventh lens (107, 207) is the smallest in the optical system (1000, 1100), lens manufacturability may be advantageous, and lens manufacturing yield may be secured. In the first and second embodiments, mathematical expression 14 may preferably satisfy 0.6 < ET7 / CT7 < 0.9.

[0423]

[0424] [Equation 15]

[0425] 1 < CT_Max / CG_Max < 2

[0426] In mathematical expression 15, CT_Max is the maximum central thickness among the lenses, and CG_Max is the maximum gap between adjacent lenses. When mathematical expression 15 is satisfied, the optical system can have good optical performance at the focal length at the set angle of view, and can reduce the TTL. In the first embodiment, mathematical expression 15 can preferably satisfy 1.5 < CT_Max / CG_Max < 2. In the second embodiment, mathematical expression 15 can preferably satisfy 1 < CT_Max / CG_Max < 1.5.

[0427]

[0428] [Equation 16]

[0429] 3 < CA_max / CA_min < 4

[0430] In mathematical expression 16, CA_max represents the maximum effective diameter among the object-side and sensor-side surfaces of the lenses, and CA_Min represents the minimum effective diameter among the object-side and sensor-side surfaces of the lenses. When mathematical expression 16 is satisfied, the optical system can set a size for a slim and compact structure while maintaining optical performance. In the first and second embodiments, mathematical expression 16 can preferably satisfy 3.3 < CA_max / CA_min < 3.6.

[0431]

[0432] [Equation 17]

[0433] 0.1 < ΣCG / ΣCT < 0.5

[0434] In mathematical expression 17, ΣCT is the sum of the central thicknesses of the lenses, and ΣCG is the sum of the spacings between adjacent lenses. When mathematical expression 17 is satisfied, the optical system can have good optical performance at the focal length at the set angle of view, and can reduce the TTL. In the first and second embodiments, mathematical expression 17 can preferably satisfy 0.3 < ΣCG / ΣCT < 0.5.

[0435]

[0436] [Equation 18]

[0437] 0.1 < CG1 / ΣCG < 0.5

[0438] In mathematical expression 18, CG1 is the center spacing between the first lens (101, 201) and the second lens (102, 202), and ΣCG is the sum of the spacings between adjacent lenses. When mathematical expression 18 is satisfied, the light emitted from the first lens (101, 201), which has a large influence in the entire optical system, sets an optical path for entering the remaining lenses, and the optical system can have good optical performance at the set angle of view and focal length. In the first and second embodiments, mathematical expression 18 can preferably satisfy 0.3 < CG1 / ΣCG < 0.5.

[0439]

[0440] [Equation 19]

[0441] 0.1 < CG1 / ΣCT < 0.5

[0442] In mathematical expression 19, CG1 is the center spacing between the first lens (101, 201) and the second lens (102, 202), and ΣCT is the sum of the center thicknesses of the lenses. When mathematical expression 19 is satisfied, the light emitted from the first lens (101, 201), which has a large influence in the entire optical system, sets an optical path for entering the remaining lenses, and the optical system can have good optical performance at the set angle of view and focal length. In the first and second embodiments, mathematical expression 19 can preferably satisfy 0.1 < CG1 / ΣCT < 0.3.

[0443]

[0444] [Equation 20]

[0445] 100 < FOV_H < 110

[0446] In mathematical expression 20, FOV_H represents the horizontal angle of view (Degree) of the optical system (1000, 1100), and can provide an angle of view suitable for a vehicle optical system. In the first and second embodiments, preferably, 105 < FOV_H < 110 can be satisfied.

[0447]

[0448] [Equation 21]

[0449] 1 < TTL / CA_max < 2

[0450] In mathematical expression 21, TTL (Total track length) means the distance (mm) from the vertex of the first surface (S1) of the first lens (101, 201) to the upper surface of the image sensor (500) on the optical axis (OA), and CA_max represents the maximum effective diameter among the object-side surfaces and the sensor-side surfaces of the lenses. When mathematical expression 21 is satisfied, the optical system can maintain good optical performance and set a size for a slim and compact structure. In the first and second embodiments, mathematical expression 21 can preferably satisfy 1.3 < TTL / CA_max < 1.8.

[0451]

[0452] [Equation 22]

[0453] 9 < TTL < 13

[0454] In mathematical expression 22, TTL (Total track length) means the distance (mm) from the center of the first surface (S1) of the first lens (101, 201) to the upper surface of the image sensor (500) on the optical axis (OA). When mathematical expression 22 is satisfied, a suitable vehicle optical system can be provided. In the first and second embodiments, mathematical expression 22 can preferably satisfy 10 < TTL < 12.

[0455]

[0456] [Equation 23]

[0457] 7 < ImgH < 8

[0458] Mathematical expression 23 indicates that ImgH represents the maximum diagonal length of the image sensor (500). Mathematical expression 23 can set the diagonal size of the image sensor (500) and provide an optical system having a sensor size for a vehicle. In the first and second embodiments, Mathematical expression 23 preferably satisfies 7 < ImgH < 7.5.

[0459]

[0460] [Equation 24]

[0461] 1 < BFL < 2

[0462] In mathematical expression 24, BFL is the optical axis distance from the image sensor (500) to the center of the sensor side of the last lens. When mathematical expression 24 is satisfied, the installation space of the filter (600) and the cover glass can be secured, the assembling of the components can be improved through the gap between the image sensor (500) and the last lens, and the joint reliability can be improved. When BFL is less than the range of mathematical expression 24, some of the light traveling to the image sensor cannot be transmitted to the image sensor, which may cause a decrease in resolution. When BFL exceeds the range of mathematical expression 24, stray light may be introduced, which may deteriorate the aberration characteristics of the optical system. In the first and second embodiments, mathematical expression 24 may preferably satisfy 1.5 < BFL < 2.

[0463]

[0464] [Equation 25]

[0465] 2 < F < 4

[0466] Mathematical expression 25 can set the overall focal length (F) to suit the vehicle optical system. In the first and second embodiments, Mathematical expression 25 can satisfy 2.8 < F < 3.2.

[0467]

[0468] [Equation 26]

[0469]

[0470] In mathematical expression 26, Z can represent Sag, which is the distance from any position on the aspherical surface to the vertex of the aspherical surface in the direction of the optical axis. Y can represent the distance from any position on the aspherical surface to the optical axis in the direction perpendicular to the optical axis. c can represent the curvature of the lens, and K can represent the conic constant. In addition, A, B, C, D, E, and F can represent aspheric coefficients.

[0471]

[0472] The optical system (1000, 1100) according to the first and second embodiments can satisfy at least one or two or more mathematical expressions from mathematical expressions 1 to 26. In this case, the optical system (1000, 1100) can have improved optical characteristics. Specifically, when the optical system (1000, 1100) satisfies at least one or two or more mathematical expressions from mathematical expressions 1 to 26, the optical system (1000, 1100) can have improved resolution and improve aberration and distortion characteristics. In addition, the optical system (1000, 1100) can secure a BFL (Back focal length) for applying a vehicle image sensor (500), can compensate for optical characteristic degradation due to temperature change, and can minimize the gap between the last lens and the image sensor (500), thereby having good optical performance at the center and periphery of the field of view (FOV).

[0473]

[0474] Table 5 shows the result values ​​for the mathematical expressions 1 to 26 described above in the optical system (1000, 1100) of the embodiment. Referring to Table 5, it can be seen that the optical system (1000, 1100) satisfies at least one, two or more, or three or more of the mathematical expressions 1 to 26. In detail, it can be seen that the optical system (1000, 1100) according to the embodiment satisfies all of the mathematical expressions 1 to 26. Accordingly, the optical system (1000, 1100) can have good optical performance and excellent optical characteristics at the center and periphery of the field of view (FOV).

[0475]

[0476] Mathematical Formula Example 1 Example 2 Example 10.2 < F / TTL < 0.3 0.27 0.2821 < TTL / ImgH < 21.51 1.4931 < |F1| / F < 21.311.2841.5 < F2 / F < 32.961.7950.01 < CT4 / F < 0.050.020.0260.01 < CT6 / F < 0.050.030.037Number of inflection points in L7 > 0SatisfiedSatisfied8Focus deviation in RGB wavelength and IR wavelength < 20umSatisfiedSatisfied92 < F / EPD < 32.2002.200100.1 < BFL / TTL < 0.30.1618180.163895111.6 < n4,n5,n6,n7 < 1.95SatisfiedSatisfied121.8 < (CAL6S1-CAL5S2) / CG5 < 2.22.000682.04369131 < |F4 / F5| < 21.0821.094140.5 < ET7 / CT7 < 10.6980.804151 < CT_Max / CG_Max < 21.8041.140163 < CA_max / CA_min < 43.5293.543170.1 < ΣCG / ΣCT < 0.50.3400.460180.1 < CG1 / ΣCG < 0.50.4490.435190.1 < CG1 / ΣCT < 0.50.1530.20020100 < FOV_H < 110107.000107.000211 < TTL / CA_max < 21.5111.477229 < TTL < 1311.00010.902237 < ImgH < 87.2807.313241 < BFL < 21.7801.787252 < F < 42.9473.004

[0477] Fig. 13 is an example of a plan view of a vehicle to which a camera module or optical system according to an embodiment of the invention is applied. Referring to Fig. 13, a vehicle camera system according to an embodiment of the invention 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) disposed in the vehicle, and may capture images of the front of the vehicle and / or the driver to generate a front image or an interior image of the vehicle. The image generating unit (11) may capture images of the surroundings of the vehicle in one or more directions as well as the front of the vehicle using the camera module (31), to generate an image of the surroundings of the vehicle. Here, the front image and the surrounding images may be digital images, and may include color images, black and white images, infrared images, etc. In addition, the front image and the surrounding images may include still images and moving images. The image generation unit (11) provides the driver image, the front image, and the surrounding image to the control unit (14). Next, the first information generation unit (12) may include at least one radar and / or camera placed in the vehicle, and detects the front of the vehicle to generate first detection information. Specifically, the first information generation unit (12) is placed in the vehicle, and detects the position and speed of vehicles located in front of the vehicle, the presence and position of pedestrians, etc. to generate first detection information.

[0478] By using the first detection information generated by the first information generating unit (12), the distance between the own vehicle and the vehicle in front can be controlled to be maintained at a constant level, and the stability of vehicle operation can be improved in specific preset cases, such as when the driver wants to change the driving lane of the own vehicle or when backing up. The first information generating unit (12) provides the first detection information to the control unit (14). The second information generating unit (21, 22, 23, 24, 25, 26) detects each side of the own vehicle based on the front image generated by the image generating unit (11) and the first detection information generated by the first information generating unit (12), and generates second detection information. Specifically, the second information generating unit (21, 22, 23, 24, 25, 26) may include at least one radar and / or camera disposed in the own vehicle, and may detect the position and speed of vehicles located on the side of the own vehicle or capture images. Here, the second information generation units (21, 22, 23, 24, 25, 26) can be placed at the front two corners, side mirrors, and rear center and rear two corners of the vehicle, respectively.

[0479] At least one information generating unit of these vehicle camera systems may be equipped with an optical system and a camera module having the same as described in the embodiments disclosed above, and may provide or process information acquired through the front, rear, each side or corner area of ​​the vehicle to a user to enable autonomous driving or to protect the vehicle and objects from surrounding safety.

[0480] The optical system of the camera module according to an embodiment of the invention can be installed in multiple units within a vehicle to enhance safety regulations, autonomous driving functions, and convenience. Furthermore, the optical system of the camera module is used as a component for controlling systems such as the Lane Keeping Assistance System (LKAS), Lane Departure Warning System (LDWS), and Driver Monitoring System (DMS). These vehicle camera modules can achieve stable optical performance even under ambient temperature changes and offer competitive pricing, thereby ensuring the reliability of vehicle components.

[0481]

[0482] The features, structures, effects, etc. described in the embodiments above are included in at least one embodiment of the present invention, and are not necessarily limited to just one embodiment. Furthermore, the features, structures, effects, etc. exemplified in each embodiment can be combined or modified in other embodiments by those skilled in the art to which the embodiments pertain. Therefore, the contents related to such combinations and modifications should be construed as falling within the scope of the present invention.

[0483] In addition, although the above description focuses on examples, these are merely examples and do not limit the present invention. Those skilled in the art to which the present invention pertains will appreciate that various modifications and applications not exemplified above are possible without departing from the essential characteristics of the present invention. For example, each component specifically shown in the examples can be modified and implemented. In addition, differences related to such modifications and applications should be interpreted as being included within the scope of the present invention defined in the appended claims.

Claims

1. Including first to seventh lenses arranged along the optical axis, The above first lens has a negative (-) refractive power, The above fourth lens has positive (+) refractive power, The above fifth lens has a negative (-) refractive power, The above sixth lens has positive (+) refractive power, The above seventh lens has a negative (-) refractive power, An optical system in which the thickness of the second lens on the optical axis is greater than the gap between the first lens and the second lens.

2. In paragraph 1, In the above optical axis, the fourth lens has a convex shape on both sides, An optical system in which the fifth lens on the optical axis has a concave shape on both sides.

3. In paragraph 1, In the above optical axis, the sixth lens has a convex shape on both sides, An optical system in which the seventh lens has a concave shape on both sides of the optical axis.

4. In paragraph 1, At least one of the first to seventh lenses has an aspherical shape on the object side and the sensor side, An optical system in which at least one of the first to seventh lenses is made of glass.

5. In paragraph 1, An optical system in which at least one of the object side and the sensor side of the seventh lens has an inflection point.

6. In paragraph 1, The above second lens has positive (+) refractive power, The above third lens is an optical system having positive (+) refractive power.

7. In any one of paragraphs 1 to 6, An optical system that satisfies the following conditions. <Conditional expression> 9 < TTL < 13 (In the above conditional expression, TTL means the distance on the optical axis from the object side of the first lens to the upper surface of the image sensor.) 8. In any one of paragraphs 1 to 6, An optical system that satisfies the following conditions. <Conditional expression> 0.5 < ET7 / CT7 < 1 (In the above conditional expression, ET7 is the edge thickness of the seventh lens, and CT7 is the thickness of the seventh lens on the optical axis.) 9. Including the first to seventh lenses arranged along the optical axis, The above first lens has a negative (-) refractive power, The above third lens has positive (+) refractive power, The above fifth lens has a negative (-) refractive power, The above sixth lens has positive (+) refractive power, The above seventh lens has a negative (-) refractive power, An optical system in which the effective diameter of the first lens among the first to seventh lenses is the largest and the effective diameter of the third lens is the smallest.

10. In paragraph 9, An optical system in which the thickness of the second lens among the first to seventh lenses on the optical axis is the greatest.

Images