Optical system and camera module

Abstract

An optical system according to an embodiment of the present invention includes a first lens having negative (−) refractive power, a second lens having negative (−) refractive power, a fifth lens having negative (−) refractive power, and a sixth lens having positive (+) refractive power, wherein a lens surface having a largest absolute value of a radius of curvature among lens surfaces of the first to sixth lenses is a sensor-side surface of the fourth lens or an object-side surface of the fifth lens.

Description

Optical system and camera module

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

[0002] ADAS (Advanced Driving Assistance System) is an advanced driver assistance system designed to assist the driver in driving. It consists of sensing the situation ahead, determining the situation based on the sensed results, and controlling the vehicle's behavior based on the situation determination. For example, ADAS sensor devices detect vehicles ahead and recognize lanes. Subsequently, once a target lane, target speed, or target ahead is determined, the vehicle's ESC (Electrical Stability Control), EMS (Engine Management System), and MDPS (Motor Driven Power Steering) are controlled. Typical examples of ADAS implementation include automatic parking systems, low-speed city driving assistance systems, and blind spot warning systems.

[0003] Sensor devices used to detect the situation ahead in ADAS include GPS sensors, laser scanners, front radar, and Lidar, but the most representative is the camera used to capture images of the front, rear, and sides of the vehicle.

[0004] Such cameras can be positioned outside or inside a vehicle to detect the surrounding conditions of the vehicle. Additionally, cameras can be positioned inside the vehicle to detect the conditions of 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 status, whether they are drowsy, whether they have been drinking, etc. Furthermore, the camera can photograph the passenger from a position adjacent to the passenger and detect whether the passenger is sleeping, their health status, etc., and provide information about the passenger to the driver.

[0005] In particular, the most important element for obtaining an image in a camera is the imaging lens that forms the image. Recently, there has been increasing interest in high performance, such as high image quality and high resolution, and research is being conducted on optical systems containing multiple lenses to achieve this. 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 outside or inside a vehicle. In this case, the camera faces the problem of being unable to uniformly produce excellent optical characteristics and aberration characteristics.

[0006] Therefore, a new optical system and camera capable of solving the aforementioned problem are required.

[0007] The embodiment aims to provide an optical system and a camera module with improved optical properties.

[0008] The embodiment aims to provide an optical system and a camera module having excellent optical performance in low to high temperature environments.

[0009] The embodiments aim to provide an optical system and a camera module capable of preventing or minimizing changes in optical properties over various temperature ranges.

[0010] To solve the above technical problem, the optical system according to the present embodiment includes first to sixth lenses arranged along an optical axis, wherein the first lens has a negative (-) refractive power, the second lens has a negative (-) refractive power, the fifth lens has a negative (-) refractive power, the sixth lens has a positive (+) refractive power, and among the lens surfaces of the first to sixth lenses, the lens surface having the largest absolute value of the radius of curvature is the sensor side of the fourth lens or the object side of the fifth lens.

[0011] Among the lens surfaces of the first to sixth lenses, the lens surface with the smallest absolute value of the radius of curvature is the sensor side of the first lens.

[0012] The refractive index of the fifth lens is greater than the refractive index of the sixth lens, and the Abbe number of the fifth lens may be smaller than the Abbe number of the sixth lens.

[0013] The absolute value of the focal length of the fourth lens may be smaller than the absolute value of the focal lengths of the first to third lenses.

[0014] In the above optical axis, the third lens has a meniscus shape that is convex toward the sensor side, and in the above optical axis, the fourth lens may have a shape that is convex on both sides.

[0015] The above third lens has a positive (+) refractive power, and the above fourth lens may have a positive (+) refractive power.

[0016] The following condition can be satisfied. <Condition> 30 < TTL < 40 (In the above condition, TTL refers to the distance from the object side of the first lens to the top plane of the image sensor along the optical axis.)

[0017] The following condition can be satisfied. <Condition> 3 < TTL / ImgH < 5 (In the above condition, TTL refers to the distance from the object side of the first lens to the top plane of the image sensor along the optical axis, and ImgH refers to the maximum diagonal length of the image sensor.)

[0018] To solve the above technical problem, the optical system according to the present embodiment includes first to sixth lenses arranged along an optical axis, wherein the first lens has a negative (-) refractive power, the second lens has a negative (-) refractive power, the third lens has a positive (+) refractive power, the fourth lens has a positive (+) refractive power, and among the lens surfaces of the first to sixth lenses, the lens surface having the largest absolute value of the radius of curvature is the sensor side of the fourth lens or the object side of the fifth lens.

[0019] In the above optical axis, the fourth lens may have both sides convex, and in the above optical axis, the fifth lens may have a meniscus shape that is convex toward the object.

[0020] In the above optical axis, the thickness of the fourth lens among the first to sixth lenses may be the largest.

[0021] The absolute value of the focal length of the fourth lens may be smaller than the absolute value of the focal lengths of the first to third lenses.

[0022] The following conditional equation may be satisfied. <Conditional Equation> 0.1 < BFL / TTL < 0.4 (In the above conditional equation, BFL refers to the optical axis distance from the image sensor to the center of the sensor side of the sixth lens, and TTL refers to the distance from the object side of the first lens to the top plane of the image sensor along the optical axis.)

[0023] The following conditional equation may be satisfied. <Conditional Equation> 0.2 < CA_max / TTL < 0.5 (In the above conditional equation, CA_max refers to the size of the largest effective aperture among the object side and sensor side of the plurality of lenses, and TTL refers to the distance from the object side of the first lens to the top plane of the image sensor along the optical axis.)

[0024] The following condition can be satisfied. <Condition> 1.5 < n4 < 1.7 (In the above condition, n4 represents the refractive index of the second lens at the d-line.)

[0025] The optical system and camera module according to the embodiment may have enhanced optical characteristics. Specifically, in the optical system according to the embodiment, a plurality of lenses may have a set thickness, refractive power, and spacing from adjacent lenses. Accordingly, the optical system and camera module according to the embodiment may have enhanced MTF characteristics, aberration control characteristics, resolution characteristics, etc., within a set angle of view range, and may have good optical performance at the periphery of the angle of view.

[0026] In addition, the optical system and camera module according to the embodiment can have good optical performance in a low to high temperature range (-40℃ to 105℃). Specifically, a plurality of lenses included in the optical system may have a set material, refractive power, and refractive index. Accordingly, if the refractive index of each lens changes due to temperature changes and the focal length of each lens changes as a result, mutual compensation can be provided by the plastic lens and the glass lens. That is, the optical system can effectively distribute the refractive power in the low to high temperature range and can prevent or minimize changes in optical characteristics in the low 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] In addition, the optical system and camera module according to the embodiment can satisfy the set angle of view through a mixture of plastic and glass lenses and achieve excellent optical characteristics. As a result, the optical system can provide a slimmer automotive camera module. Accordingly, the optical system and camera module can be provided for various applications and devices, and can possess excellent optical characteristics even when exposed to harsh temperature environments, such as the exterior of a vehicle or the interior of a vehicle at high temperatures during the summer.

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

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

[0030] Figure 3 is a table showing the Sag values ​​of the aspherical lens surfaces among the first to sixth lenses in the optical system of Figure 1.

[0031] Figure 4 is a graph showing data for the diffraction MTF (Modulation Transfer Function) of the optical system of Figure 1 at room temperature.

[0032] Figure 5 is a graph showing data on the aberration characteristics of the optical system of Figure 1 at room temperature.

[0033] Figure 6 is a graph showing data for the diffraction MTF of the optical system of Figure 1 at low temperature.

[0034] Figure 7 is a graph showing data on the aberration characteristics of the optical system of Figure 1 at low temperature.

[0035] Figure 8 is a graph showing data for the diffraction MTF at high temperature of the optical system of Figure 1.

[0036] Figure 9 is a graph showing data on the aberration characteristics of the optical system of Figure 1 at high temperatures.

[0037] Figure 10 is a graph showing the ambient light ratio data of the optical system of Figure 1.

[0038] FIG. 11 is a side cross-sectional view of an optical system according to a second embodiment and a camera module having the same.

[0039] Figure 12 is a table showing the aspherical coefficients of the lenses in the optical system of Figure 11.

[0040] Figure 13 is a table showing the Sag values ​​of the aspherical lens surfaces among the first to sixth lenses in the optical system of Figure 11.

[0041] Figure 14 is a graph showing data for the diffraction MTF (Modulation Transfer Function) of the optical system of Figure 11 at room temperature.

[0042] Figure 15 is a graph showing data on the aberration characteristics of the optical system of Figure 11 at room temperature.

[0043] Figure 16 is a graph showing data for the diffraction MTF of the optical system of Figure 11 at low temperature.

[0044] Figure 17 is a graph showing data on the aberration characteristics of the optical system of Figure 11 at low temperatures.

[0045] Figure 18 is a graph showing data for the diffraction MTF at high temperature of the optical system of Figure 11.

[0046] Figure 19 is a graph showing data on the aberration characteristics of the optical system of Figure 11 at high temperatures.

[0047] Figure 20 is a graph showing the ambient light ratio data of the optical system of Figure 11.

[0048] FIG. 21 is an example of a vehicle having an optical system according to an embodiment of the invention.

[0049] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings.

[0050] However, the technical concept of the present invention is not limited to some of the described embodiments but can be implemented in various different forms, and within the scope of the technical concept of the present invention, one or more of the components among the embodiments may be selectively combined or substituted.

[0051] In addition, terms used in this embodiment (including technical and scientific terms) may be interpreted in a sense that is generally understood by those skilled in the art to which this embodiment belongs, unless explicitly and specifically defined otherwise. Terms that are commonly used, such as terms defined in advance, may be interpreted in consideration of their meaning in the context of the relevant technology.

[0052] Furthermore, the terms used in this embodiment are for the purpose of describing the embodiment and are not intended to limit the invention.

[0053] In this specification, the singular form may include the plural form unless specifically stated otherwise in the text, and when described as "at least one of A and B and C (or more than one)," it may include one or more of all combinations that can be formed from A, B, and C.

[0054] In addition, terms such as first, second, A, B, (a), (b), etc., may be used when describing the components of the present embodiment. These terms are used merely to distinguish the components from other components and are not intended to limit the essence, order, or sequence of the components.

[0055] And, where it is stated that a component is 'connected', 'combined', or 'connected' to another component, this may include not only cases where the component is directly 'connected', 'combined', or 'connected' to the other component, but also cases where it is 'connected', 'combined', or 'connected' due to another component located between the component and the other component.

[0056] Furthermore, when described as being formed or placed "above" or "below" each component, "above" or "below" includes not only cases where two components are in direct contact with each other, but also cases where one or more other components are formed or placed between the two components. Additionally, when expressed as "above" or "below," it may include the meaning of a downward direction as well as an upward direction relative to a single component.

[0057] In the description of the invention, "object side" may refer to a surface of the lens facing the object side with respect to the optical axis (OA), and "sensor side" may refer to a surface of the lens facing the imaging surface (image sensor) with respect to the optical axis. "Object side" may be the "object side," and "sensor side" may be the "image side." One surface of the lens being convex may refer to a convex shape in the optical axis or paraxial region, and one surface of the lens being concave may refer to a concave shape in the optical axis or paraxial region. The radius of curvature, center thickness, and optical axis spacing between lenses listed in the lens data table may refer to values ​​(unit, mm) in the optical axis. The vertical direction may refer to a direction perpendicular to the optical axis, and the end of the lens or lens surface may refer to the end of the effective area of ​​the 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 paraxial region refers to a very narrow region near the optical axis, and is a region where the distance of light rays from the optical axis (OA) is almost zero. Hereinafter, the term optical axis may include the center of each lens or a very narrow region near the optical axis.

[0058]

[0059] As shown in FIGS. 1 and FIGS. 11, the optical system (1000, 1100) according to the first and second embodiments of the present invention may include five or more lenses. The optical system (1000, 1100) and the camera module having the same 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 as glass or plastic, and the coefficient of linear expansion of glass material is smaller than that of plastic material. Accordingly, glass lenses are employed to suppress changes in the focusing position due to temperature changes. Through plastic lenses, good correction of various aberrations such as spherical aberration and chromatic aberration may be possible. In addition, plastic lenses may provide aspherical lenses, thereby minimizing distortion in the periphery. Furthermore, the material of the lenses may be a glass mold lens having an aspherical surface among glass materials. Glass mold lenses can be manufactured by placing an optical glass ingot inside a mold that will have an aspherical shape and undergoing a heating and compression process.

[0060] The optical system (1000, 1100) may include n lenses, the nth lens is the last lens adjacent to the image sensor (300), and the (n-1)th lens may be the lens closest to the last lens. n is an integer greater than or equal to 5, for example, 5 to 6.

[0061] Each lens (101-106, 201-206) may have an object side and a sensor side. The optical system may have fewer lenses with aspherical sensor sides and aspherical object sides than glass lenses. The optical system may have more lenses with spherical sensor sides and spherical object sides than lenses with aspherical surfaces on both sides. The optical system (1000, 1100) may have more spherical lenses than aspherical lenses.

[0062] Among the lenses of the optical system (1000, 1100), the maximum refractive index may be 1.9 or higher. The chromatic dispersion of incident light can be increased by the lens having the maximum refractive index, and the center thickness may be thinner than the edge thickness.

[0063]

[0064] The effective diameter may be the diameter of the effective area where effective light is incident from each lens. The effective diameter is the length in the direction (X,Y) perpendicular to the optical axis and is the average of the effective diameter of the object side and the effective diameter of the sensor side of each lens. "Diameter of the lens surface" may refer to the "effective diameter of the lens." "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 lens flange is not illustrated in FIG. 1 and FIG. 11, the flange may be a portion formed to protrude perpendicular to the optical axis from the side of the lens so that the lens can be coupled to the barrel. Effective light may not be incident on the flange. A spacer may be additionally placed between the flanges of different lenses to allow the lenses to be coupled to the barrel.

[0065] Each of the lenses (101-106, 201-206) may include an effective region and an ineffective region. The effective region may be an area through which light incident on each of the lenses passes. That is, the effective region may be defined as an effective area or effective mirror where the incident light is refracted to realize optical properties. The ineffective region may be positioned around the periphery of the effective region. The ineffective region may be an area where effective light is not incident from the plurality of lenses. That is, the ineffective region may be an area unrelated to optical properties. Additionally, the end of the ineffective region may be an area fixed to a lens barrel or the like that accommodates the lens.

[0066]

[0067] Within the optical system (1000, 1100), the Total Top Length (TTL) may be more than 7 times Imgh, for example, more than 7 times and less than or equal to 7.5 times. The Total Track Length (TTL) is the distance along the optical axis (OA) from the center of the object side of the first lens to the top plane of the image sensor (300). Imgh is twice the distance between the diagonal ends of the image sensor (300) and the optical axis (OA), or the maximum diagonal length. Within the optical system (1000, 1100), the Effective Focal Length (EFL) may be provided as 10 mm or more and the Field of View (FOV) as less than 60 degrees, so that it can be provided as a standard optical system in a vehicle camera module. For example, the optical system and camera module according to the embodiment may be applied to a camera for an Advanced Driving Assistance System (ADAS) installed inside or outside a vehicle.

[0068] The optical system (1000, 1100) may have a TTL / Imgh condition of 3 or more and 5 or less, for example, 3 or more and 4 or less. By setting the TTL / Imgh value of the optical system (1000, 1100) to 3 or more and 5 or less, a vehicle lens optical system can be provided. Accordingly, the optical system (1000, 1100) can provide an image without exaggeration or distortion regarding the formed image.

[0069]

[0070] The effective diameter of at least one glass lens within the optical system (1000, 1100) may be greater than the length of the image sensor (300). The effective diameter is the diameter or length of the effective area where light is incident. The length of the image sensor (300) is the maximum length of the diagonal in the direction orthogonal to the optical axis (OA). There may not be a number of lenses within the optical system (1000, 1100) having an effective diameter smaller than the length of the image sensor (300).

[0071] The effective diameter of the lens closest to the object side within the lens section may be larger than the effective diameter of the lens closest to the image sensor (300). 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 diameters of each lens, the optical system (1000, 1100) can control the incident light to compensate for the degradation of optical characteristics due to resolution and temperature changes, improve chromatic aberration control characteristics, and improve the vignetting characteristics of the optical system (1000, 1100).

[0072] The lens portion may include first to sixth lenses (101-106, 201-206) aligned along the optical axis from the object side toward the sensor side. Within the lens portion, when the focal length is taken as an absolute value, the focal length of the lens closest to the object may be greater than the focal length of the lens closest to the image sensor.

[0073] The lens portion may be disposed in a camera module having an inner barrel on one side or the entire inner surface of a lens barrel. The lens portion may be disposed in a camera module having a plurality of inner barrels around the circumference of different lenses of the lens barrel. The lens portion may be disposed 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 portion may be disposed in a camera module having a plurality of inner barrels each disposed between the outer surface of at least one or two or more lenses and the lens barrel. The lens portion may be disposed in a camera module in which the plurality of inner barrels have a material different from the material of the lens barrel.

[0074] Among the lenses constituting the lens section, at least some of the plastic lenses may be placed in an inner barrel positioned within the lens barrel. Through this, the optical system (1000, 1100) can maintain resolution in response to temperature changes. The lens section is positioned in a camera module having a different type of barrel to minimize decentering of lenses, such as plastic lenses, that expand in response to temperature changes. The lens barrel in which the lens section is positioned is provided with a plurality of inner barrels within the lens barrel, thereby maintaining the resolution of the optical system in response to temperature changes and suppressing deformation of the lenses.

[0075]

[0076] In the lens portion, the minimum effective diameter may be in the range of 10mm to 11mm, and the maximum effective diameter may be in the range of 13mm to 14mm. Additionally, the optical system (1000, 1100) can improve resolution and chromatic aberration control characteristics by controlling incident light, and can improve the vignetting characteristics of the optical system (1000, 1100).

[0077]

[0078] An optical system (1000, 1100) or a camera module may include an image sensor (300). The image sensor (300) can detect light and convert it into an electrical signal. The image sensor (300) can detect light that has passed through a lens section sequentially. The image sensor (300) may include a device capable of detecting incident light, such as a Charge Coupled Device (CCD) or a Complementary Metal Oxide Semiconductor (CMOS).

[0079] Here, the number of lenses having an effective diameter larger than the length of the image sensor (300) is 0 to 2, and the number of lenses having an effective diameter smaller than the length of the image sensor (300) may be 4 to 6.

[0080]

[0081] The optical system (1000, 1100) or camera module may include a filter (400). The filter (400) may be placed between the last lens and the image sensor (300). The filter (400) may be placed between the lens closest to the sensor side among the lenses of the lens unit and the image sensor (300). For example, the filter (400) may be placed between the nth lens and the image sensor (300).

[0082] The cover glass (500) is placed between the filter (400) and the image sensor (300), protects the top of the image sensor (300), and can prevent a decrease in the reliability of the image sensor (300). The cover glass (500) can be removed. The cover glass (500) may be a protective glass.

[0083] The filter (400) may include an infrared filter or an infrared cut-off filter (IR cut-off). The filter (400) may pass light of a set wavelength band and filter light of a different wavelength band. If the filter (400) includes an infrared filter, it may block radiant heat emitted from external light from being transmitted to the image sensor (300). Additionally, the filter (400) may transmit visible light and reflect infrared light.

[0084] 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).

[0085] In the optical system (1000, 1100) of the first and second embodiments, the sum of the refractive indices of the lenses in the lens section may be 10 or more, for example, in the range of 10 to 15, and the average refractive index may be in the range of 1.7 to 1.9. The sum of the Abbe numbers of each lens may be 200 or more, for example, in the range of 230 to 270, and the average Abbe number may be 50 or less, for example, in the range of 30 to 50. The sum of the center thicknesses of the entire lens may be 10 mm or more, for example, in the range of 15 mm to 20 mm, and the average of the center thicknesses may be in the range of 2 mm to 4 mm. The sum of the center spacings between the lenses on the optical axis (OA) may be 10 mm or more, for example, in the range of 10 mm to 15 mm, and may be smaller than the sum of the center thicknesses of the lenses. In addition, the average value of the effective diameter of each lens surface (S1-S12) of the lens section may be 10 mm or more, for example, in the range of 10 mm to 15 mm.

[0086]

[0087] In the optical system according to the first and second embodiments of the invention, the angle of view (diagonal) may be 60 degrees or less, for example, in the range of 40 to 60 degrees. The F number of the optical system or camera module may be 2.0 or less, for example, in the range of 1.0 to 2.0 or in the range of 1.0 to 1.5. In the automotive optical system, the horizontal angle of view (FOV_H) in the Y-axis direction may be greater than 40 degrees and less than 50 degrees, for example, in the range of 44 to 48 degrees. In addition, the vertical angle of view is provided at an angle smaller than the horizontal angle of view, and may be 40 degrees or less, for example, in the range of 25 to 35 degrees. The horizontal angle of view (FOV_H) is the angle of view based on the horizontal length of the sensor. Accordingly, it is possible to suppress changes in the focus position due to temperature changes and to provide a vehicle camera in which various aberrations are well corrected.

[0088] Since the optical system applied to a vehicle camera typically monitors road conditions, it may be designed based on the horizontal angle of view rather than the entire angle of view. The optical system according to the present embodiment is designed with a certain margin based on the inscribed circle of the image sensor. Optical performance can be guaranteed in the area that satisfies the range of the horizontal angle of view (FOV_H).

[0089] For driver monitoring, front / rear recording of the vehicle, or lane detection and detection of sudden objects around the vehicle during vehicle operation, the field of view may be greater than 40 degrees and less than 50 degrees, for example, in the range of 44 to 48 degrees. This horizontal field of view may be a preset angle for an Advanced Driver Assistance System (ADAS).

[0090] 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.

[0091]

[0092] An optical system according to the first embodiment of the invention will be described.

[0093] 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 the aspherical coefficients of the lenses in the optical system of FIG. 1, FIG. 3 is a table showing the Sag values ​​of the aspherical lens surfaces among the first to sixth lenses in the optical system of FIG. 1, FIG. 4 is a graph showing data on the diffraction MTF (Modulation Transfer Function) of the optical system of FIG. 1 at room temperature, FIG. 5 is a graph showing data on the aberration characteristics of the optical system of FIG. 1 at room temperature, FIG. 6 is a graph showing data on the diffraction MTF of the optical system of FIG. 1 at low temperature, FIG. 7 is a graph showing data on the aberration characteristics of the optical system of FIG. 1 at low temperature, FIG. 8 is a graph showing data on the diffraction MTF of the optical system of FIG. 1 at high temperature, FIG. 9 is a graph showing data on the aberration characteristics of the optical system of FIG. 1 at high temperature, FIG. 10 is a graph showing peripheral light ratio data of the optical system of FIG. 1.

[0094] Referring to FIG. 1, the optical system (1000) includes a lens portion, and the lens portion may include a first lens (101) to a sixth lens (106). The first to sixth lenses (101 to 106) may be arranged sequentially 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 sixth lens (106) and a filter (400) and be incident on an image sensor (300).

[0095] The first lens (101) may be positioned closest to the object side. The first lens (101) may be positioned furthest from the sensor side. The first lens (101) may have a negative (-) refractive power at the optical axis (OA). The first lens (101) may include plastic or glass material, for example, glass material. The first lens (101) may be a glass mold lens made of glass material having an aspherical surface. A glass mold lens may be manufactured by placing an optical glass ingot inside a mold that will have an aspherical shape and through a heating and compression process. The first surface (S1) and the second surface (S2) of the first lens (101) may be aspherical.

[0096] With respect to the optical axis, the first surface (S1) on the object side of the first lens (101) may be convex, and the second surface (S2) on the sensor side may be concave. The first lens (101) may have a meniscus shape that is convex toward the object side. The first lens (101) may have a meniscus shape that is concave toward the sensor side. At least one or both of the first surface (S1) and the second surface (S2) may be provided without a threshold point from the optical axis (OA) to the end of the effective area.

[0097]

[0098] The second lens (102) may be positioned second from the object side. The second lens (102) may be positioned fifth from the sensor side. The second lens (102) may be positioned between the first lens (101) and the third lens (103). The second lens (102) may have a negative (-) refractive power at the optical axis (OA). The second lens (102) may include plastic or glass material. For example, the second lens (102) may be provided with glass material.

[0099] With respect to the optical axis (OA), the object-side third surface (S3) of the second lens (102) may be concave, and the sensor-side fourth surface (S4) may be convex. The second lens (102) may have a meniscus shape that is convex toward the sensor side. The second lens (102) may have a meniscus shape that is concave toward the object side. The second lens (102) is made of glass material and may have a spherical surface. At least one or both of the third surface (S3) and the fourth surface (S4) may be spherical. At least one or both of the third surface (S3) and the fourth surface (S4) 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 positioned as the third lens from the object side. The third lens (103) may be positioned as the fourth lens from the sensor side. The third lens (103) may be positioned between the second lens (102) and the fourth lens (104). The third lens (103) may have a positive (+) refractive power at the optical axis (OA). The third lens (103) may include plastic or glass material. For example, the third lens (103) may be provided with glass material.

[0102] With respect to the optical axis, the object-side fifth surface (S5) of the third lens (103) may be concave, and the sensor-side sixth surface (S6) may be convex. The third lens (103) may have a meniscus shape that is convex toward the sensor side. The third lens (103) may have a meniscus shape that is concave toward the object side. The third lens (103) may be made of glass material 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. An aperture (Stop) may be placed around the sensor-side sixth surface (S6) of the third lens (103). An aperture (Stop) may be placed around the object-side seventh surface (S7) of the fourth lens (104). The aperture can reduce TTL within the angle of view range, and the optical system can be miniaturized. Accordingly, it is possible to prevent a decrease in yield by weight of the optical system and improve production efficiency. In addition, the optical system can be miniaturized by reducing TTL at a horizontal angle of view (FOV_H) of 40 to 50 degrees.

[0103]

[0104] The fourth lens (104) may be positioned as the fourth lens from the object side. The fourth lens (104) may be positioned as the third lens from the sensor side. The fourth lens (104) may be positioned between the third lens (103) and the fifth lens (105). The fourth lens (104) may have a positive (+) refractive power at the optical axis (OA). The fourth lens (104) may include plastic or glass material. For example, the fourth lens (104) may be provided with glass material.

[0105] With respect to the optical axis, the object-side seventh surface (S7) of the fourth lens (104) may be convex, and the sensor-side eighth surface (S8) may be convex. The fourth lens (104) may have a shape with both sides convex. The fourth lens (104) may be made of glass material and may be spherical. At least one or both of the seventh surface (S7) and the eighth surface (S8) may be spherical. At least one or both of the seventh surface (S7) and the eighth surface (S8) may be provided without a threshold point from the optical axis (OA) to the end of the effective area.

[0106]

[0107] The fifth lens (105) may be positioned as the fifth lens from the object side. The fifth lens (105) may be positioned as the second lens from the sensor side. The fifth lens (105) may be positioned between the fourth lens (104) and the sixth lens (106). The fifth lens (105) may have a negative (-) refractive power at the optical axis (OA). The fifth lens (105) may include plastic or glass materials. For example, the fifth lens (105) may be provided with glass material.

[0108] With respect to the optical axis, the object-side ninth surface (S9) of the fifth lens (105) may be convex, and the sensor-side tenth surface (S10) may be concave. The fifth lens (105) may have a meniscus shape with the sensor side being concave. The fifth lens (105) may have a meniscus shape with the object side being convex. The fifth lens (105) may be made of glass material and may be spherical. At least one or both of the ninth surface (S9) and the tenth surface (S10) may be spherical. At least one or both of the ninth surface (S9) and the tenth surface (S10) of the fifth lens (105) may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0109]

[0110] The sixth lens (106) may be positioned as the sixth one from the object side. The sixth lens (106) may be positioned closest to the sensor side. The sixth lens (106) may have a positive (+) refractive power at the optical axis (OA). The sixth lens (106) may include plastic or glass material, for example, glass material. The sixth lens (106) may be a glass mold lens made of glass material having an aspherical surface. A glass mold lens may be manufactured by placing an optical glass ingot inside a mold that will have an aspherical shape and through a heating and compression process. The eleventh surface (S11) and the twelfth surface (S12) of the sixth lens (106) may be aspherical.

[0111] With respect to the optical axis, the object-side 11th surface (S11) of the 6th lens (106) may be convex, and the sensor-side 12th surface (S12) may be convex. The 6th lens (106) may have a shape with both sides convex. At least one or both of the 11th surface (S11) and the 12th surface (S12) may be aspherical. At least one or both of the 11th surface (S11) and the 12th surface (S12) may be provided without a threshold point from the optical axis (OA) to the end of the effective area.

[0112]

[0113] LensSurfaceRadiusThicknessndvdSemiApertureFocal length1S16.9611.6011.81540.9486.637-28.985 S24.8217.283 5.469 2S1-7.2853.5001.91735.2494.821-32.723 S2-11.8320.100 6.162 3S1-52.2462.9261.88840.8056.42025.673 S2-16.2920.150 6.717 StopStopInfinity0.100 6.550 4S110.5004.4881.55275.4956.92318.203 S2-198.6122.299 6.742 5S1212.7241.0001.93320.8806.089-13.086 S211.5230.200 5.733 6S110.1393.6611.77149.1975.93512.472 S2-156.3789.352 5.490 FilterS1Infinity0.210 5.177Infinity S2Infinity0.100 5.172 CoverS1Infinity0.500 5.168Infinity S2Infinity0.431 5.157 ImageImage

[0114] Table 1 shows the surface number, radius of curvature, thickness of the center of each lens or distance between lens surfaces, index, nd, Abbe number (Abbe,vd), effective radius (Semi Aperture), and focal length of a lens according to the first embodiment of the present invention. At this time, the units of the radius of curvature and the thickness or distance may be mm.

[0115]

[0116] Item ValueItem ValueΣIndex10.876ET11.967ΣAbbe262.574ET23.591ΣCT17.175ET31.873ΣCG10.132ET41.700CA_max13.846ET52.446CA_min9.642ET62.038CA_Aver12.260F -number1.400CT_max4.488SD21.000CT_min1.000TD36.659CT_Aver2.863VFOV29.5ImgH10.29HFOV46.1TTL37.900DFOV55.1BFL10.593EPD15.571F(EFL)10.800

[0117] Table 2 is for items of the mathematical formulas described above in the optical system (1000) of the first embodiment, and is for the TTL (Total track length) (mm), BFL (Back focal length), effective focal length (F) (mm), ImgH (mm), effective diameter (CA) (mm), thickness (mm), TTL (mm), optical axis distance from the first plane (S1) to the twelfth plane (S12) TD (mm), optical axis distance from the aperture (Stop) to the twelfth plane (S12) SD (mm), sum of refractive indices, sum of Abbe numbers, sum of thicknesses (mm), sum of spacing between adjacent lenses, effective diameter characteristics, diagonal field of view (DFOV) (Degree), vertical field of view (VFOV) (Degree), horizontal field of view (HFOV) (Degree), edge thickness (ET), F number, etc. of the optical system (1000).

[0118]

[0119] The center thickness of the first to sixth lenses (101 to 106) is denoted as CT1 to CT6, the edge thickness of the effective area of ​​each lens is denoted as ET1 to ET6, and the center gap between two adjacent lenses is denoted as CG1 to CG5. BFL (Back focal length) is the optical axis distance from the image sensor (300) 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 top surface of the image sensor (300).

[0120] As shown in FIG. 2, among the lenses of the lens portion of the first embodiment, the lens surfaces of the first and sixth lenses (101, 106) may include an aspherical surface having a 30th-order aspherical coefficient. For example, the first and sixth lenses (101, 106) may include a lens surface having a 30th-order aspherical coefficient. As described above, an aspherical surface having a 30th-order aspherical coefficient (a non-zero value) can significantly change the shape of the aspherical surface in the periphery, and thus can effectively correct the optical performance of the periphery of the field of view (FOV).

[0121]

[0122] When compared by the absolute values ​​of the radius of curvature of each lens, the radius of curvature of the ninth surface (S9) of the fifth lens (105) at the optical axis (OA) may be the maximum among the lenses, and the radius of curvature of the second surface (S2) of the first lens (101) may be the minimum among the lenses. The difference between the maximum radius of curvature and the minimum radius of curvature may be 40 times or more, for example, in the range of 40 to 50 times.

[0123] Among the lens surfaces of the lenses, the lens surface with the largest absolute value of the radius of curvature may be the sensor side (8th surface (S8)) of the 4th lens (104) or the object side (9th surface (S9)) of the 5th lens (105). By designing the radius of curvature of the mutually facing surfaces of the adjacently positioned 4th lens (104) and 5th lens (105) to be large, a shape close to a flat plane is formed, thereby setting the light path incident on the image sensor (300) to be gentle, and by designing the spacing between the 4th lens (104) and 5th lens (105) appropriately, the optical system (1000) can be miniaturized.

[0124] Among the lens surfaces of the lenses, the lens surface with the smallest absolute value of the radius of curvature may be the sensor side (second surface (S2)) of the first lens (101). If this is satisfied, a low F-number can be secured within the set angle of view and focal length of the optical system (1000), and aberration control can be performed in the optical system (1000) designed with a large effective aperture. The absolute value of the radius of curvature of the sensor side (second surface (S2)) of the first lens (101) may satisfy 4 mm to 8 mm, and preferably 4 mm to 5 mm.

[0125] The absolute value of the radius of curvature of the first surface (S1) of the first lens (101) may be greater than the absolute value of the radius of curvature of the second surface (S2). The absolute value of the radius of curvature of the third surface (S3) of the second lens (102) may be smaller than the absolute value of the radius of curvature of the fourth surface (S4). The absolute value of the radius of curvature of the fifth surface (S5) of the third lens (103) may be greater than the absolute value of the radius of curvature of the sixth surface (S6). The absolute value of the radius of curvature of the seventh surface (S7) of the fourth lens (104) may be smaller than the absolute value of the radius of curvature of the eighth surface (S8). The absolute value of the radius of curvature of the ninth surface (S9) of the fifth lens (105) may be greater than the absolute value of the radius of curvature of the tenth surface (S10). The absolute value of the radius of curvature of the 11th surface (S11) of the 6th lens (106) may be smaller than the absolute value of the radius of curvature of the 12th surface (S12).

[0126] The ratio of the radius of curvature of each lens can satisfy the following conditions.

[0127] Condition 1: 1.5 < |L1R1 / L1R2| < 2

[0128] Condition 2: 0.5 < |L2R1 / L2R2| < 1

[0129] Condition 3: 3 < |L3R1 / L3R2| < 3.5

[0130] Condition 4: 0.05 < |L4R1 / L4R2| < 0.1

[0131] Condition 5: 15 < |L5R1 / L5R2| < 20

[0132] Condition 6: 0.05 < |L6R1 / L6R2| < 0.1

[0133]

[0134] When describing the center thickness of the lenses based on the optical axis, the center thickness (CT4) of the fourth lens (104) is the largest among the lenses, and the center thickness (CT5) of the fifth lens (105) is the smallest among the lenses. The difference between the maximum center thickness and the minimum center thickness among the lenses may be in the range of 3 mm or more and 5 mm or less.

[0135] The center thickness of each lens can satisfy any one of the following conditions.

[0136] Condition 1: CT2, CT3, CT4, CT6 > CT1 > CT5

[0137] Condition 2: CT4, CT6 > CT2 > CT1, CT3, CT5

[0138] Condition 3: CT2, CT4, CT6 > CT3 > CT1, CT5

[0139] Condition 4: CT4 > CT1, CT2, CT3, CT5, CT6

[0140] Condition 5: CT1, CT2, CT3, CT4, CT6 > CT5

[0141] Condition 6: CT4 > CT6 > CT1, CT2, CT3, CT5

[0142]

[0143] To describe the center spacing (CG) between the lenses, the center spacing (CG1) between the first lens (101) and the second lens (102) may be maximum, and the center spacing (CG2) between the second and third lenses (102, 103) may be minimum. The difference between the maximum center spacing and the minimum center spacing among the spaced-out lens spacings may be 7 mm or more, for example, in the range of 7 mm to 8 mm.

[0144] The center spacing between each lens can satisfy the following conditions.

[0145] Condition 1: CG1 > CG2, CG3, CG4, CG5

[0146] Condition 2: CG1, CG3, CG4, CG5 > CG2

[0147] Condition 3: CG1, CG4 > CG3 > CG2, CG5

[0148] Condition 4: CG1 > CG4 > CG2, CG3, CG5

[0149] Condition 5: CG1, CG3, CG4 > CG5 > CG2

[0150]

[0151] Regarding the effective diameter, the effective diameter of the fourth lens (104) is maximum, and the lens having the maximum effective diameter may be a glass lens. Here, the effective diameter is the average of the effective diameter of the object side and the effective diameter of the sensor side of each lens. The lens surface having the maximum effective diameter may be the seventh surface (S7) of the fourth lens (104). The effective diameter of the second lens (102) may be minimum within the lens portion. The lens surface having the minimum effective diameter may be the third surface (S3) of the second lens (102).

[0152] The effective diameter of each lens can satisfy any one of the following conditions.

[0153] Condition 1: CA_L3, CA_L4 > CA_L1 > CA_L2, CA_L5, CA_L6

[0154] Condition 2: CA_L1, CA_L3, CA_L4, CA_L5, CA_L6 > CA_L2

[0155] Condition 3: CA_L4 > CA_L3 > CA_L1, CA_L2, CA_L5, CA_L6

[0156] Condition 4: CA_L4 > CA_L1, CA_L2, CA_L3, CA_L5, CA_L6

[0157] Condition 5: CA_L1, CA_L3, CA_L4 > CA_L5 > CA_L2, CA_L6

[0158] Condition 6: CA_L1, CA_L3, CA_L4, CA_L5 > CA_L6 > CA_L2

[0159]

[0160] Regarding the refractive index, the refractive index of the fifth lens (105) is the maximum among the lenses and may be greater than 1.7, for example, greater than 1.9. The fourth lens (104) may have the minimum refractive index among the lenses. For example, the refractive index of the fourth lens (104) may be the minimum among the lenses and may be less than 1.7, for example, less than 1.6. The difference between the maximum refractive index and the minimum refractive index may be 0.3 or greater.

[0161] The refractive index of each lens can satisfy any one of the following conditions.

[0162] Condition 1: n2, n3, n5 > n1 > n4, n6

[0163] Condition 2: n5 > n2 > n1, n3, n4, n6

[0164] Condition 3: n2, n5 > n3 > n1, n4, n6

[0165] Condition 4: n1, n2, n3, n5, n6 > n4

[0166] Condition 5: n5 > n1, n2, n3, n4, n6

[0167] Condition 6: n1, n2, n3, n5 > n6 > n4

[0168]

[0169] When comparing the Abbe numbers, the Abbe number of the fourth lens (104) is the maximum among the lenses and may be 60 or more. The Abbe number of the fifth lens (105) is the minimum among the lenses and may be 25 or less. The difference between the maximum Abbe number and the minimum Abbe number may be 50 or more.

[0170] The Abbe number of each lens can satisfy any one of the following conditions.

[0171] Condition 1: v4, v6 > v1 > v2, v3, v5

[0172] Condition 2: v1, v3, v4, v6 > v2 > v5

[0173] Condition 3: v1, v4, v6 > v3 > v2, v5

[0174] Condition 4: v4 > v1, v2, v3, v5, v6

[0175] Condition 5: v1, v2, v3, v4, v6 > v5

[0176] Condition 6: v4 > v6 > v1, v2, v3, v5

[0177]

[0178] The focal lengths (F3, F4, F6) of the 3rd, 4th, and 6th lenses (103, 104, 106) may have a positive (+) sign. The 3rd, 4th, and 6th lenses (103, 104, 106) may have a positive (+) refractive power. The focal lengths (F1, F2, F5) of the 1st, 2nd, and 5th lenses (101, 102, 105) may have a negative (-) sign. The 1st, 2nd, and 5th lenses (101, 102, 105) may have a negative (-) refractive power.

[0179] The fifth lens (105) and the sixth lens (106), which are lenses placed adjacent to each other, can satisfy the following conditions.

[0180] Condition 1: Refractive index of a lens with positive refractive power < Refractive index of a lens with negative refractive power

[0181] Condition 2: Dispersion of positive refractive power lens > Dispersion of negative refractive power lens

[0182] Here, among the glass lenses, the fifth lens (105) has a negative (-) refractive power and the sixth lens (106) has a positive (+) refractive power. According to conditions 1 and 2, the refractive index of the fifth lens (105) is greater than the refractive index of the sixth lens (106), and the dispersion value (Abbe number) of the fifth lens (105) is smaller than the dispersion value (Abbe number) of the sixth lens (106). Chromatic aberration occurring in glass lenses can be corrected with glass lenses. Additionally, the chromatic aberration occurring in glass lenses can be compensated with plastic lenses by satisfying the refractive index difference of 0.1 or more and 0.3 or less and the Abbe number difference of 20 or more and 50 or less between the fifth lens (105) and the sixth lens (106), which are plastic lenses arranged in succession.

[0183] Optical systems are subject to chromatic aberration, which is corrected by using bonded lenses or two lenses arranged in succession. As the temperature changes from low to high temperatures, the lenses repeatedly contract and expand. Since lenses made of the same material exhibit the same change in lens characteristics due to temperature variations, it is effective to correct chromatic aberration using lenses of the same material even when the temperature changes. Additionally, as deformation may occur in the bonding of bonded lenses in high-temperature environments, the two adjacent lenses can be designed to have similar radii of curvature on their opposing surfaces and spaced apart from the center at an equal or similar interval to achieve an effect similar to that of bonded lenses.

[0184]

[0185] When comparing the absolute values ​​of the focal lengths, the focal length of the second lens (102) is the largest among the lenses and may be 30 or more and 40 or less. Among the lenses, the second lens (102), which is made of glass material, may have the largest focal length and the smallest refractive power. The focal length of the sixth lens (106) is the smallest among the lenses, and the absolute value of the focal length of the sixth lens (106) may be 10 or more and 15 or less. Among the lenses, the sixth lens (106), which is made of glass mold material, may have the smallest focal length and the largest refractive power.

[0186] Among the lenses, the lens having the minimum focal length may be the sixth lens (106). The difference between the maximum focal length and the minimum focal length may be 15 or more, or 20 or more. Accordingly, the optical system may have improved MTF characteristics, aberration control characteristics, resolution characteristics, etc., within the angle of view range set in the optical system, and may have good optical performance at the periphery of the angle of view.

[0187] The absolute value of the focal length of the lens placed on the sensor side of the aperture (STOP) may be smaller than the absolute value of the focal length of the lenses placed on the object side of the aperture (STOP). When the aperture (STOP) is placed between the third lens (103) and the fourth lens (104), the absolute value of the focal length of the fourth lens (104) may be smaller than the absolute value of the focal lengths of the first to third lenses (101, 102, 103). Since the influence of the lens placed adjacent to the aperture (STOP) is significant within the optical system, a lens with high refractive power may be placed adjacent to the aperture (STOP) to compensate for the focal length increase caused by the lens expanding at high temperatures.

[0188] The absolute value of the focal length of each lens can satisfy any one of the following conditions.

[0189] Condition 1: |f2| > |f1| > |f3|, |f4|, |f5|, |f6|

[0190] Condition 2: |f2| > |f1|, |f3|, |f4|, |f5|, |f6|

[0191] Condition 3: |f1|, |f2| > |f3| > |f4|, |f5|, |f6|

[0192] Condition 4: |f1|, |f2|, |f3| > |f4| > |f5|, |f6|

[0193] Condition 5: |f1|, |f2|, |f3|, |f4| > |f5| > |f6|

[0194] Condition 6: |f1|, |f2|, |f3|, |f4|, |f5| > |f6|

[0195]

[0196] 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 to 1.5 times the minimum thickness. The thickness (T2) of the second lens (102) may be maximum at the edge and minimum 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 1.5 to 2 times the minimum thickness. The thickness (T4) of the fourth lens (104) may be maximum at the center and minimum at the edge, and the maximum thickness is in the range of 2.5 to 3 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 to 2.5 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 1.5 to 2 times the minimum thickness.

[0197] The thickness of each lens can satisfy any one of the following conditions.

[0198] Condition 1: 0.5 < CT1 / ET1 < 1, 1 < ET1 / CT1 < 1.5

[0199] Condition 2: 0.5 < CT2 / ET2 < 1, 1 < ET2 / CT2 < 1.5

[0200] Condition 3: 1.5 < CT3 / ET3 < 2, 0.5 < ET3 / CT3 < 1

[0201] Condition 4: 2.5 < CT4 / ET4 < 3, 0.1 < ET4 / CT4 < 0.5

[0202] Condition 5: 0.1 < CT5 / ET5 < 0.5, 2 < ET5 / CT5 < 2.5

[0203] Condition 6: 1.5 < CT6 / ET6 < 2, 0.5 < ET6 / CT6 < 1

[0204] Condition 7: 1 < ΣCT / ΣET < 1.5, 0.5 < ΣET / ΣCT < 1

[0205]

[0206] Among the gaps (G1-G5) between the lenses, the first gap (G1) between the first and second lenses (101, 102) may have a maximum center and a minimum edge. The second gap (G2) between the second and third lenses (102, 103) may have a minimum center and a maximum edge. The third gap (G3) between the third and fourth lenses (103, 104) may have a maximum edge and a minimum center. The fourth gap (G4) between the fourth and fifth lenses (104, 105) may have a maximum edge and a minimum center. The fifth gap (G5) between the fifth and sixth lenses (105, 106) may have a maximum edge and a minimum center.

[0207]

[0208] FIGS. 4, 6, and 8 are graphs showing the modulation transfer function (MTF) of the diffraction at room temperature, low temperature, and high temperature in the optical system of FIG. 1, and graphs showing the modulation of luminance according to spatial frequency. As shown in FIGS. 4, 6, and 8, in the first embodiment of the invention, the deviation of the MTF from low temperature or high temperature relative to room temperature may be less than 10%, i.e., 7% or less.

[0209] Figures 5, 7, and 9 are graphs showing the aberration characteristics of the optical system of Figure 1 at room temperature, low temperature, and high temperature. The aberration graphs in Figures 5, 7, and 9 show the longitudinal spherical aberration, astigmatic field curves, and distortion measured from left to right. In Figures 5, 7, and 9, the X-axis may represent focal length (mm) and distortion (%), and the Y-axis may represent the height of the image. Additionally, the graph for longitudinal spherical aberration is for light in the wavelength bands of approximately 435 nm, approximately 486 nm, approximately 546 nm, approximately 587 nm, and approximately 656 nm, while the graphs for astigmatic field curves and distortion are for light in the wavelength band of approximately 546 nm. In the aberration diagrams of FIGS. 5, 7, and 9, it can be interpreted that the closer the curves at room temperature, low temperature, and high temperature are to the Y-axis, the better the aberration correction function is. In the optical system (1000) according to the first embodiment, it can be seen that the measured values ​​are adjacent 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 at the center of the field of view (FOV) but also at the periphery. Here, the low temperature is -20 degrees or lower, for example, in the range of -20 to -40 degrees; the room temperature is 22 degrees ± 5 degrees or 18 degrees to 27 degrees; and the high temperature is 85 degrees or higher, for example, in the range of 85 degrees to 105 degrees. Accordingly, it can be seen that the decrease in luminance modulation from low temperature to high temperature in FIGS. 5, 7, and 9 is less than 10%, for example, 5% or less, or hardly changes.

[0210]

[0211] Room Temperature Low Temperature High Temperature Low Temperature / Room Temperature High Temperature / Room Temperature EFL(F) 10.900 10.897 10.907 99.97% 100.06% TTL 3 7.900 37.86 13 7.95 399.89% 100.13% BFL 10.59 3 10.575 10.61 699.83% 100.21% EPD 15.57 115.56 115.578 99.93% 100.04% ImgH 10.29 10.29 10.29 100% 100% F# 1.400 1.400 1.400 100% 100% DFOV 5 5.96 75 6.00 955.908 100.07% 99.89% MTF focus position Shift0.0um2.5um-2um--

[0212] As shown in Table 3, changes in optical properties according to temperature changes from low to high temperatures are indicated. It can be seen that the rate of change in optical properties at low temperatures is 5% or less, for example, 3% or less, relative to room temperature. For example, it can be seen that the rate of change in effective focal length (EFL), TTL, BFL, EPD, ImgH, F#, and DFOV is 10% or less, i.e., 5% or less, for example, in the range of 0 to 5%. Table 3 compares the MTF focus position shift in the optical system according to the first embodiment, and the MTF focus position shift at low and high temperatures can satisfy a range of 10 µm or less relative to room temperature, for example, a range of 6 µm or less.

[0213] 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.

[0214]

[0215] We will now describe an optical system according to the second embodiment of the invention.

[0216] FIG. 11 is a side cross-sectional view of an optical system according to a second embodiment and a camera module having the same; FIG. 12 is a table showing the aspherical coefficients of the lenses in the optical system of FIG. 11; FIG. 13 is a table showing the Sag values ​​of the aspherical lens surfaces among the first to sixth lenses in the optical system of FIG. 11; FIG. 14 is a graph showing data on the diffraction MTF (Modulation Transfer Function) of the optical system of FIG. 11 at room temperature; FIG. 15 is a graph showing data on the aberration characteristics of the optical system of FIG. 11 at room temperature; FIG. 16 is a graph showing data on the diffraction MTF of the optical system of FIG. 11 at low temperature; FIG. 17 is a graph showing data on the aberration characteristics of the optical system of FIG. 11 at low temperature; FIG. 18 is a graph showing data on the diffraction MTF of the optical system of FIG. 11 at high temperature; FIG. 19 is a graph showing data on the aberration characteristics of the optical system of FIG. 11 at high temperature; FIG. 20 is FIG This is a graph showing the ambient light ratio data of the optical system of 11.

[0217] Referring to FIG. 11, the optical system (1100) includes a lens portion, and the lens portion may include a first lens (201) to a sixth lens (206). The first to sixth lenses (201 to 206) may be arranged sequentially 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 sixth lens (206) and a filter (400) and be incident on an image sensor (300).

[0218] The first lens (201) may be positioned closest to the object side. The first lens (201) may be positioned furthest from the sensor side. The first lens (201) may have a negative (-) refractive power at the optical axis (OA). The first lens (201) may include plastic or glass material, for example, glass material. The first lens (201) may be a glass mold lens made of glass material having an aspherical surface. A glass mold lens may be manufactured by placing an optical glass ingot inside a mold that will have an aspherical shape and through a heating and compression process. The first surface (S1) and the second surface (S2) of the first lens (201) may be aspherical.

[0219] With respect to the optical axis, the first surface (S1) on the object side of the first lens (201) may be convex, and the second surface (S2) on the sensor side may be concave. The first lens (201) may have a meniscus shape that is convex toward the object side. The first lens (201) may have a meniscus shape that is concave toward the sensor side. At least one or both of the first surface (S1) and the second surface (S2) may be provided without a threshold point from the optical axis (OA) to the end of the effective area.

[0220]

[0221] The second lens (202) may be positioned second from the object side. The second lens (202) may be positioned fifth from the sensor side. The second lens (202) may be positioned between the first lens (201) and the third lens (203). The second lens (202) may have a negative (-) refractive power at the optical axis (OA). The second lens (202) may include plastic or glass material. For example, the second lens (202) may be provided with glass material.

[0222] With respect to the optical axis (OA), the object-side third surface (S3) of the second lens (202) may be concave, and the sensor-side fourth surface (S4) may be convex. The second lens (202) may have a meniscus shape that is convex toward the sensor side. The second lens (202) may have a meniscus shape that is concave toward the object side. The second lens (202) is made of glass material and may have a spherical surface. At least one or both of the third surface (S3) and the fourth surface (S4) may be spherical. At least one or both of the third surface (S3) and the fourth surface (S4) may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0223]

[0224] The third lens (203) may be positioned as the third lens from the object side. The third lens (203) may be positioned as the fourth lens from the sensor side. The third lens (203) may be positioned between the second lens (202) and the fourth lens (204). The third lens (203) may have a positive (+) refractive power at the optical axis (OA). The third lens (203) may include plastic or glass material. For example, the third lens (203) may be provided with glass material.

[0225] With respect to the optical axis, the fifth surface (S5) on the object side of the third lens (203) may be concave, and the sixth surface (S6) on the sensor side may be convex. The third lens (203) may have a meniscus shape that is convex toward the sensor side. The third lens (203) may have a meniscus shape that is concave toward the object side. The third lens (203) may be made of glass material 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.

[0226] The aperture (Stop) can be positioned around the perimeter of the sensor-side sixth surface (S6) of the third lens (203). The aperture (Stop) can be positioned around the perimeter of the object-side seventh surface (S7) of the fourth lens (204). The aperture can reduce TTL within the angle of view range, and the optical system can be miniaturized. Accordingly, a decrease in 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 TTL at a horizontal angle of view (FOV_H) of 40 to 50 degrees.

[0227]

[0228] The fourth lens (204) may be positioned as the fourth lens from the object side. The fourth lens (204) may be positioned as the third lens from the sensor side. The fourth lens (204) may be positioned between the third lens (203) and the fifth lens (205). The fourth lens (204) may have a positive (+) refractive power at the optical axis (OA). The fourth lens (204) may include plastic or glass material. For example, the fourth lens (204) may be provided with glass material.

[0229] With respect to the optical axis, the object-side seventh surface (S7) of the fourth lens (204) may be convex, and the sensor-side eighth surface (S8) may be convex. The fourth lens (204) may have a shape with both sides convex. The fourth lens (204) may be made of glass material and may be spherical. At least one or both of the seventh surface (S7) and the eighth surface (S8) may be spherical. At least one or both of the seventh surface (S7) and the eighth surface (S8) may be provided without a threshold point from the optical axis (OA) to the end of the effective area.

[0230]

[0231] The fifth lens (205) may be positioned as the fifth lens from the object side. The fifth lens (205) may be positioned as the second lens from the sensor side. The fifth lens (205) may be positioned between the fourth lens (204) and the sixth lens (206). The fifth lens (205) may have a negative (-) refractive power at the optical axis (OA). The fifth lens (205) may include plastic or glass material. For example, the fifth lens (205) may be provided with glass material.

[0232] With respect to the optical axis, the object-side ninth surface (S9) of the fifth lens (205) may be concave, and the sensor-side tenth surface (S10) may be concave. The fifth lens (205) may have a shape with both sides concave. The fifth lens (205) may be made of glass material and may be spherical. At least one or both of the ninth surface (S9) and the tenth surface (S10) may be spherical. At least one or both of the ninth surface (S9) and the tenth surface (S10) of the fifth lens (205) may be provided without a threshold point from the optical axis (OA) to the end of the effective area.

[0233]

[0234] The sixth lens (206) may be positioned as the sixth one from the object side. The sixth lens (206) may be positioned closest to the sensor side. The sixth lens (206) may have a positive (+) refractive power at the optical axis (OA). The sixth lens (206) may include plastic or glass material, for example, glass material. The sixth lens (206) may be a glass mold lens made of glass material having an aspherical surface. A glass mold lens may be manufactured by placing an optical glass ingot inside a mold that will have an aspherical shape and through a heating and compression process. The eleventh surface (S11) and the twelfth surface (S12) of the sixth lens (206) may be aspherical.

[0235] With respect to the optical axis, the object-side 11th surface (S11) of the 6th lens (206) may be convex, and the sensor-side 12th surface (S12) may be convex. The 6th lens (206) may have a shape with both sides convex. At least one or both of the 11th surface (S11) and the 12th surface (S12) may be aspherical. At least one or both of the 11th surface (S11) and the 12th surface (S12) may be provided without a threshold point from the optical axis (OA) to the end of the effective area.

[0236]

[0237] LensSurfaceRadiusThicknessndvdSemiApertureFocal length1S18.2332.3951.81540.9486.600-22.886 S24.9653.178 4.957 2S1-6.8235.6071.93320.8804.743-34.895 S2-10.6180.100 5.894 3S1-21.7942.2111.88840.8055.96429.845 S2-12.5310.100 6.200 StopStopInfinity0.1006.3534S112.0244.0151.59568.6236.60016.590 S2-48.2184.435 6.517 5S1-22.7291.0001.93320.8805.828-12.049 S222.7260.200 5.941 6S114.6253.9521.69653.0486.17110.881 S2-13.9619.283 6.284 FilterS1Infinity0.210 Infinity S2Infinity0.100 CoverS1Infinity0.500 Infinity S2Infinity0.431 ImageImage

[0238] Table 4 shows the surface number, radius of curvature, thickness of the center of each lens or distance between lens surfaces, index, nd, Abbe number (Abbe,vd), effective radius (Semi Aperture), and focal length of the lens according to the second embodiment of the present invention. At this time, the units of the radius of curvature and the thickness or distance may be mm.

[0239]

[0240] Item ValueItem ValueΣIndex10.860ET12.710ΣAbbe245.184ET23.384ΣCT16.826ET31.402ΣCG10.541ET41.599CA_max13.200ET52.550CA_min9.485ET61.599CA_Aver12.008F -number1.400CT_max4.015SD22.885CT_min1.000TD36.576CT_Aver2.804VFOV29.7ImgH10.29HFOV46.4TTL37.900DFOV55.2BFL10.532EPD15.428F(EFL)10.900

[0241] Table 5 is for the items of the mathematical formulas described above in the optical system (1100) of the second embodiment, and is for the TTL (Total track length) (mm), BFL (Back focal length), effective focal length (F) (mm), ImgH (mm), effective diameter (CA) (mm), thickness (mm), TTL (mm), optical axis distance from the first plane (S1) to the twelfth plane (S12) TD (mm), optical axis distance from the aperture (Stop) to the twelfth plane (S12) SD (mm), sum of refractive indices, sum of Abbe numbers, sum of thicknesses (mm), sum of spacing between adjacent lenses, effective diameter characteristics, diagonal field of view (DFOV) (Degree), vertical field of view (VFOV) (Degree), horizontal field of view (HFOV) (Degree), edge thickness (ET), F number, etc. of the optical system (1100).

[0242]

[0243] The center thickness of the first to sixth lenses (201 to 206) is denoted as CT1 to CT6, the edge thickness of the effective area of ​​each lens is denoted as ET1 to ET6, and the center gap between two adjacent lenses is denoted as CG1 to CG5. BFL (Back focal length) is the optical axis distance from the image sensor (300) 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 (201) to the top surface of the image sensor (300).

[0244] As shown in FIG. 12, among the lenses of the lens unit in the second embodiment, the lens surfaces of the first and sixth lenses (201, 206) may include an aspherical surface having a 30th-order aspherical coefficient. For example, the first and sixth lenses (201, 206) may include a lens surface having a 30th-order aspherical coefficient. As described above, an aspherical surface having a 30th-order aspherical coefficient (a non-zero value) can significantly change the shape of the aspherical surface in the periphery, and thus can effectively correct the optical performance of the periphery of the field of view (FOV).

[0245]

[0246] When compared by the absolute values ​​of the radius of curvature of each lens, the radius of curvature of the 8th surface (S8) of the 4th lens (204) at the optical axis (OA) may be the maximum among the lenses, and the radius of curvature of the 2nd surface (S2) of the 1st lens (201) may be the minimum among the lenses. The difference between the maximum radius of curvature and the minimum radius of curvature may be five times or more, for example, in the range of eight to ten times.

[0247] Among the lens surfaces of the lenses, the lens surface with the largest absolute value of the radius of curvature may be the sensor side (8th surface (S8)) of the 4th lens (204) or the object side (9th surface (S9)) of the 5th lens (205). By designing the radius of curvature of the mutually facing surfaces of the adjacently positioned 4th lens (204) and 5th lens (205) to be large, a shape close to a flat plane is formed, thereby setting the light path incident on the image sensor (300) to be gentle, and by appropriately designing the spacing between the 4th lens (204) and 5th lens (205), the optical system (1000) can be miniaturized.

[0248] Among the lens surfaces of the lenses, the lens surface with the smallest absolute value of the radius of curvature may be the sensor side (second surface (S2)) of the first lens (201). If this is satisfied, a low F-number can be secured within the set angle of view and focal length of the optical system (1100), and aberration control can be performed in the optical system (1100) designed with a large effective aperture. The absolute value of the radius of curvature of the sensor side (second surface (S2)) of the first lens (201) may satisfy 4 mm to 8 mm, and preferably 4 mm to 5 mm.

[0249] The absolute value of the radius of curvature of the first surface (S1) of the first lens (201) may be greater than the absolute value of the radius of curvature of the second surface (S2). The absolute value of the radius of curvature of the third surface (S3) of the second lens (202) may be smaller than the absolute value of the radius of curvature of the fourth surface (S4). The absolute value of the radius of curvature of the fifth surface (S5) of the third lens (203) may be greater than the absolute value of the radius of curvature of the sixth surface (S6). The absolute value of the radius of curvature of the seventh surface (S7) of the fourth lens (204) may be smaller than the absolute value of the radius of curvature of the eighth surface (S8). The absolute value of the radius of curvature of the ninth surface (S9) of the fifth lens (205) may be greater than the absolute value of the radius of curvature of the tenth surface (S10). The absolute value of the radius of curvature of the 11th surface (S11) of the 6th lens (206) may be greater than the absolute value of the radius of curvature of the 12th surface (S12).

[0250] The ratio of the radius of curvature of each lens can satisfy the following conditions.

[0251] Condition 1: 1.5 < |L1R1 / L1R2| < 2

[0252] Condition 2: 0.5 < |L2R1 / L2R2| < 1

[0253] Condition 3: 1.5 < |L3R1 / L3R2| < 2

[0254] Condition 4: 0.1 < |L4R1 / L4R2| < 0.5

[0255] Condition 5: 1 < |L5R1 / L5R2| < 1.5

[0256] Condition 6: 1 < |L6R1 / L6R2| < 1.5

[0257]

[0258] When describing the center thickness of the lenses based on the optical axis, the center thickness (CT4) of the fourth lens (204) is the largest among the lenses, and the center thickness (CT5) of the fifth lens (205) is the smallest among the lenses. The difference between the maximum center thickness and the minimum center thickness among the lenses may be in the range of 3 mm or more and 5 mm or less.

[0259] The center thickness of each lens can satisfy any one of the following conditions.

[0260] Condition 1: CT2, CT4, CT6 > CT1 > CT3, CT5

[0261] Condition 2: CT4, CT6 > CT2 > CT1, CT3, CT5

[0262] Condition 3: CT1, CT2, CT4, CT6 > CT3 > CT5

[0263] Condition 4: CT4 > CT1, CT2, CT3, CT5, CT6

[0264] Condition 5: CT1, CT2, CT3, CT4, CT6 > CT5

[0265] Condition 6: CT4 > CT6 > CT1, CT2, CT3, CT5

[0266]

[0267] To explain the center spacing (CG) between the lenses, the center spacing (CG1) between the first lens (201) and the second lens (202) may be maximum, and the center spacing (CG2) between the second and third lenses (202, 203) may be minimum. The difference between the maximum center spacing and the minimum center spacing among the spaced-out lens spacings may be 5 mm or more, for example, in the range of 5.5 mm to 6.0 mm.

[0268] The center spacing between each lens can satisfy the following conditions.

[0269] Condition 1: CG1 > CG2, CG3, CG4, CG5

[0270] Condition 2: CG1, CG3, CG4, CG5 > CG2

[0271] Condition 3: CG1, CG4 > CG3 = CG5 > CG2

[0272] Condition 4: CG1 > CG4 > CG2, CG3, CG5

[0273]

[0274] Regarding the effective diameter, the effective diameter of the fourth lens (204) is maximum, and the lens having the maximum effective diameter may be a lens made of glass material. Here, the effective diameter is the average of the effective diameter of the object side of each lens and the effective diameter of the sensor side. The lens surface having the maximum effective diameter may be the seventh surface (S7) of the fourth lens (204).

[0275] The effective diameter of the second lens (202) may be the minimum within the lens portion. The lens surface having the minimum effective diameter may be the third surface (S3) of the second lens (202).

[0276] The effective diameter of each lens can satisfy any one of the following conditions.

[0277] Condition 1: CA_L3, CA_L4, CA_L5, CA_L6 > CA_L1 > CA_L2

[0278] Condition 2: CA_L1, CA_L3, CA_L4, CA_L5, CA_L6 > CA_L2

[0279] Condition 3: CA_L4, CA_L6 > CA_L3 > CA_L1, CA_L2, CA_L5

[0280] Condition 4: CA_L4 > CA_L1, CA_L2, CA_L3, CA_L5, CA_L6

[0281] Condition 5: CA_L3, CA_L4, CA_L6 > CA_L5 > CA_L1, CA_L2

[0282] Condition 6: CA_L4 > CA_L6 > CA_L1, CA_L2, CA_L3, CA_L5

[0283]

[0284] Regarding the refractive indices, the refractive indices of the second lens (202) and the fifth lens (205) are the maximum among the lenses and may be greater than 1.7, for example, greater than 1.9. The fourth lens (204) may have the minimum refractive index among the lenses. For example, the refractive index of the fourth lens (204) may be the minimum among the lenses and may be less than 1.7, for example, less than 1.6. The difference between the maximum refractive index and the minimum refractive index may be 0.3 or greater.

[0285] The refractive index of each lens can satisfy any one of the following conditions.

[0286] Condition 1: n2, n3, n5 > n1 > n4, n6

[0287] Condition 2: n2 = n5 > n1, n3, n4, n6

[0288] Condition 3: n2, n5 > n3 > n1, n4, n6

[0289] Condition 4: n1, n2, n3, n5, n6 > n4

[0290] Condition 5: n1, n2, n3, n5 > n6 > n4

[0291]

[0292] When comparing the Abbe numbers, the Abbe number of the fourth lens (204) is the maximum among the lenses and may be 60 or more. The Abbe numbers of the second lens (202) and the fifth lens (205) are the minimum among the lenses and may be 25 or less. The difference between the maximum Abbe number and the minimum Abbe number may be 40 or more.

[0293] The Abbe number of each lens can satisfy any one of the following conditions.

[0294] Condition 1: v4, v6 > v1 > v2, v3, v5

[0295] Condition 2: v1, v3, v4, v6 > v2 = v5

[0296] Condition 3: v1, v4, v6 > v3 > v2, v5

[0297] Condition 4: v4 > v1, v2, v3, v5, v6

[0298] Condition 5: v1, v2, v3, v4, v6 > v5

[0299]

[0300] The focal lengths (F3, F4, F6) of the 3rd, 4th, and 6th lenses (203, 204, 206) may have a positive (+) sign. The 3rd, 4th, and 6th lenses (203, 204, 206) may have a positive (+) refractive power. The focal lengths (F1, F2, F5) of the 1st, 2nd, and 5th lenses (201, 202, 205) may have a negative (-) sign. The 1st, 2nd, and 5th lenses (201, 202, 205) may have a negative (-) refractive power.

[0301] The fifth lens (205) and the sixth lens (206), which are lenses placed adjacently, can satisfy the following conditions.

[0302] Condition 1: Refractive index of a lens with positive refractive power < Refractive index of a lens with negative refractive power

[0303] Condition 2: Dispersion of positive refractive power lens > Dispersion of negative refractive power lens

[0304] Here, among the glass lenses, the fifth lens (205) has a negative (-) refractive power and the sixth lens (206) has a positive (+) refractive power. According to conditions 1 and 2, the refractive index of the fifth lens (205) is greater than the refractive index of the sixth lens (206), and the dispersion value of the fifth lens (205) is smaller than the dispersion value of the sixth lens (206). Chromatic aberration occurring in the glass lenses can be corrected with glass lenses. Additionally, the chromatic aberration occurring in the glass lenses can be compensated with plastic lenses by satisfying the refractive index difference of 0.1 or more and 0.3 or less and the Abbe number difference of 20 or more and 50 or less between the fifth lens (205) and the sixth lens (206), which are plastic lenses arranged in succession.

[0305] Optical systems are subject to chromatic aberration, which is corrected by using bonded lenses or two lenses arranged in succession. As the temperature changes from low to high temperatures, the lenses repeatedly contract and expand. Since lenses made of the same material exhibit the same change in lens characteristics due to temperature variations, it is effective to correct chromatic aberration using lenses of the same material even when the temperature changes. Additionally, as deformation may occur in the bonding of bonded lenses in high-temperature environments, the two adjacent lenses can be designed to have similar radii of curvature on their opposing surfaces and spaced apart from the center at an equal or similar interval to achieve an effect similar to that of bonded lenses.

[0306]

[0307] When comparing the absolute values ​​of the focal lengths, the focal length of the second lens (202) is the largest among the lenses and may be 30 or more and 40 or less. Among the lenses, the second lens (202), which is made of glass material, may have the largest focal length and the smallest refractive power. The focal length of the sixth lens (206) is the smallest among the lenses, and the absolute value of the focal length of the sixth lens (206) may be 10 or more and 15 or less. Among the lenses, the sixth lens (206), which is made of glass mold material, may have the smallest focal length and the largest refractive power.

[0308] Among the lenses, the lens having the minimum focal length may be the sixth lens (206). The difference between the maximum focal length and the minimum focal length may be 15 or more or 20 or more. Accordingly, the optical system may have improved MTF characteristics, aberration control characteristics, resolution characteristics, etc. within the angle of view range set in the optical system, and may have good optical performance at the periphery of the angle of view.

[0309] The absolute value of the focal length of the lens placed on the sensor side of the aperture (STOP) may be smaller than the absolute value of the focal length of the lenses placed on the object side of the aperture (STOP). When the aperture (STOP) is placed between the third lens (203) and the fourth lens (204), the absolute value of the focal length of the fourth lens (204) may be smaller than the absolute value of the focal lengths of the first to third lenses (102, 202, 203). Since the influence of the lens placed adjacent to the aperture (STOP) is significant within the optical system, a lens with high refractive power may be placed adjacent to the aperture (STOP) to compensate for the focal length increase caused by the lens expanding at high temperatures.

[0310] The absolute value of the focal length of each lens can satisfy any one of the following conditions.

[0311] Condition 1: |f2|, |f3| > |f1| > |f4|, |f5|, |f6|

[0312] Condition 2: |f2| > |f1|, |f3|, |f4|, |f5|, |f6|

[0313] Condition 3: |f2| > |f3| > |f1|, |f4|, |f5|, |f6|

[0314] Condition 4: |f1|, |f2|, |f3| > |f4| > |f5|, |f6|

[0315] Condition 5: |f1|, |f2|, |f3|, |f4| > |f5| > |f6|

[0316] Condition 6: |f1|, |f2|, |f3|, |f4|, |f5| > |f6|

[0317]

[0318] 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 1 to 1.5 times the minimum thickness. The thickness (T2) of the second lens (202) may be maximum at the edge and minimum 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 1.5 to 2 times the minimum thickness. The thickness (T4) of the fourth lens (204) may be maximum at the center and minimum at the edge, and the maximum thickness is in the range of 2.5 to 3 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 2.5 to 3 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.

[0319] The thickness of each lens can satisfy any one of the following conditions.

[0320] Condition 1: 0.5 < CT1 / ET1 < 1, 1 < ET1 / CT1 < 1.5

[0321] Condition 2: 0.5 < CT2 / ET2 < 1, 1 < ET2 / CT2 < 1.5

[0322] Condition 3: 1.5 < CT3 / ET3 < 2, 0.5 < ET3 / CT3 < 1

[0323] Condition 4: 2.5 < CT4 / ET4 < 3, 0.1 < ET4 / CT4 < 0.5

[0324] Condition 5: 0.1 < CT5 / ET5 < 0.5, 2.5 < ET5 / CT5 < 3

[0325] Condition 6: 2 < CT6 / ET6 < 2.5, 0.1 < ET6 / CT6 < 0.5

[0326] Condition 7: 1 < ΣCT / ΣET < 1.5, 0.5 < ΣET / ΣCT < 1

[0327]

[0328] Among the gaps (G1-G5) between the lenses, the first gap (G1) between the first and second lenses (201, 202) may have a maximum center and a minimum edge. The second gap (G2) between the second and third lenses (202, 203) may have a minimum center and a maximum edge. The third gap (G3) between the third and fourth lenses (203, 204) may have a maximum edge and a minimum center. The fourth gap (G4) between the fourth and fifth lenses (204, 205) may have a minimum edge and a maximum center. The fifth gap (G5) between the fifth and sixth lenses (205, 206) may have a maximum edge and a minimum center.

[0329]

[0330] FIGS. 14, 16, and 18 are graphs showing the modulation transfer function (MTF) of the diffraction at room temperature, low temperature, and high temperature in the optical system of FIG. 1, and graphs showing the modulation of luminance according to spatial frequency. As shown in FIGS. 14, 16, and 18, in the second embodiment of the invention, the deviation of the MTF from low temperature or high temperature relative to room temperature may be less than 10%, i.e., 7% or less.

[0331] FIGS. 15, 17, and 19 are graphs showing the aberration characteristics of the optical system of FIG. 11 at room temperature, low temperature, and high temperature. The aberration graphs in FIGS. 15, 17, and 19 show the longitudinal spherical aberration, astigmatic field curves, and distortion measured from left to right. In FIGS. 15, 17, and 19, the X-axis may represent focal length (mm) and distortion (%), and the Y-axis may represent the height of the image. Additionally, the graph for longitudinal spherical aberration is for light in the wavelength bands of approximately 435 nm, approximately 486 nm, approximately 546 nm, approximately 587 nm, and approximately 656 nm, while the graphs for astigmatic field curves and distortion are for light in the wavelength band of approximately 546 nm. In the aberration diagrams of FIGS. 15, 17, and 19, it can be interpreted that the aberration correction function is better as the curves at room temperature, low temperature, and high temperature are closer to the Y-axis, and it can be seen that the optical system (1100) according to the second embodiment has measured values ​​adjacent to the Y-axis in almost most areas. That is, 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. Here, the low temperature is -20 degrees or lower, for example, in the range of -20 to -40 degrees; the room temperature is 22 degrees ± 5 degrees or 18 degrees to 27 degrees; and the high temperature is 85 degrees or higher, for example, in the range of 85 degrees to 105 degrees. Accordingly, it can be seen that the decrease in the modulation of luminance from low to high temperatures in FIGS. 15, FIGS. 17, and FIGS. 19 is less than 10%, for example, 5% or less, or hardly changes.

[0332]

[0333] Room Temperature Low Temperature High Temperature Low Temperature / Room Temperature High Temperature / Room Temperature EFL(F)10.80010.79610.80899.96%100.07%TTL37.90037.86337.86399.90%99.90BFL10.53210.51910.55199.87%100.18%EPD15.42815.41715.43799.92%100.05%ImgH10.2910.2910.29100%100%F#1.4001.4001.400100%100%DFOV55.52455.55855.474100.06%99.90%MTF focus position Shift0.0um3.8um-0.1um--

[0334] As shown in Table 6, changes in optical properties according to temperature changes from low to high temperatures are indicated. It can be seen that the rate of change in optical properties at low temperatures is 5% or less, for example, 3% or less, relative to room temperature. For example, it can be seen that the rate of change in effective focal length (EFL), TTL, BFL, EPD, ImgH, F#, and DFOV is 10% or less, i.e., 5% or less, for example, in the range of 0 to 5%. Table 3 compares the MTF focus position shift in the optical system according to the second embodiment, and the MTF focus position shift at low and high temperatures can satisfy a range of 10 µm or less relative to room temperature, for example, a range of 6 µm or less.

[0335] 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.

[0336]

[0337] The optical system (1000, 1100) according to the first and second embodiments disclosed above may satisfy at least one or two of the mathematical formulas described below. Accordingly, the optical system (1000, 1100) according to the first and second embodiments may have improved optical characteristics. For example, if the optical system (1000, 1100) satisfies at least one mathematical formula, the optical system (1000, 1100) can effectively control aberration characteristics such as chromatic aberration and distortion aberration, and may have good optical performance not only at the center of the field of view (FOV) but also at the periphery. In addition, the optical system (1000, 1100) may have improved resolution. Furthermore, regarding the meaning of the thickness of the lens at the optical axis (OA) and the spacing of adjacent lenses at the optical axis (OA) described in the mathematical formulas, one may refer to the first and second embodiments disclosed above.

[0338]

[0339] The optical system (1000, 1100) according to the first and second embodiments disclosed above may satisfy at least one or two of the mathematical formulas described below. Accordingly, the optical system (1000, 1100) according to the first and second embodiments may have improved optical characteristics. For example, if the optical system (1000, 1100) satisfies at least one mathematical formula, the optical system (1000, 1100) can effectively control aberration characteristics such as chromatic aberration and distortion aberration, and may have good optical performance not only at the center of the field of view (FOV) but also at the periphery. In addition, the optical system (1000, 1100) may have improved resolution. Furthermore, regarding the meaning of the thickness of the lens at the optical axis (OA) and the spacing of adjacent lenses at the optical axis (OA) described in the mathematical formulas, one may refer to the first and second embodiments disclosed above.

[0340]

[0341] [Mathematical Formula 1]

[0342] 1 < CA_max*F-number / ImgH < 2

[0343] In Equation 1, CA_max represents the largest effective diameter (mm) among the object side and sensor side of the plurality of lenses, F-number represents the brightness of the entire optical system, and ImgH represents the maximum diagonal length of the image sensor (300). When Equation 1 is satisfied, a bright image can be obtained from a large image sensor, and the size of the entire optical system (length in the direction of the optical axis and length in the direction perpendicular to the direction of the optical axis) can be reduced. If it is less than the lower limit of Equation 1, there is a problem that the size of the entire optical system cannot be reduced, and if it exceeds the upper limit of Equation 1, there is a problem that a bright image cannot be received. In the first and second embodiments, Equation 1 can preferably satisfy 1.5 < CA_max*F-number / ImgH < 2.

[0344]

[0345] [Mathematical Formula 2]

[0346] |Number of positive power lenses - Number of negative power lenses| ≤ 1

[0347] Equation 2 is a factor related to temperature compensation design to minimize changes in optical performance even when the temperature changes, when the optical system (1000, 1100) is placed in a vehicle. The smaller the difference between the number of lenses with positive (+) refractive power and the number of lenses with negative (-) refractive power satisfying Equation 2, the smaller the effect on optical performance when the temperature changes.

[0348]

[0349] [Mathematical Formula 3]

[0350] 0 < |BFL(Low Temperature)-BFL(High Temperature)| < 0.1

[0351] In Equation 3, BFL is the optical axis distance from the image sensor (300) to the center of the sensor side of the last lens. Equation 3 is a factor related to temperature compensation design to minimize changes in optical performance even when the optical system (1000, 1100) is placed in a vehicle and the temperature changes. The smaller the difference between BFL at low temperature and BFL at high temperature by satisfying Equation 3, the less the effect on optical performance can be when the temperature changes. In the first and second embodiments, Equation 3 can preferably satisfy 0 < |BFL(low temperature)-BFL(high temperature)| < 0.05.

[0352]

[0353] [Mathematical Formula 4]

[0354] 1 < |F1| / F < 3

[0355] In Equation 4, F1 is the focal length of the first lens (101, 201), and F is the effective focal length of the optical system. If Equation 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 vehicles can be provided. Additionally, the angle of view can be set large within an appropriate TTL range through the first lens (101, 201) having negative (-) refractive power. If it is below the lower limit of Equation 4, the effective aperture or TTL of the lenses becomes longer, which may cause a problem where the imaging lens system becomes large. If it exceeds the upper limit of Equation 4, the influence of the first lens (101, 201) in the entire optical system decreases, and it becomes necessary to increase the refractive power of the lenses, which makes it difficult to correct spherical aberration or distortion aberration. In the first and second embodiments, Equation 4 is preferably such that 2 < |F1| / F < 2.7 can be satisfied.

[0356]

[0357] [Mathematical Formula 5]

[0358] 0.2 < CA_max / TTL < 0.5

[0359] In Equation 5, CA_max represents the largest effective diameter (mm) among the object side and sensor side of the plurality of lenses, and TTL (Total track length) represents the distance (mm) along the optical axis (OA) from the vertex of the first surface (S1) of the first lens (101, 201) to the top surface of the image sensor (300). Equation 5 establishes the relationship between the total optical axis length of the optical system and the maximum effective diameter, thereby providing a miniaturized optical system for vehicles. In the first and second embodiments, Equation 5 preferably satisfies 0.3 < CA_max / TTL < 0.4.

[0360]

[0361] [Mathematical Formula 6]

[0362] 0.1 < BFL / TTL < 0.4

[0363] In Equation 6, TTL (Total track length) refers to the distance (mm) along the optical axis (OA) from the vertex of the first surface (S1) of the first lens (101, 201) to the top surface of the image sensor (300), and BFL refers to the optical axis distance from the image sensor (300) to the center of the sensor side of the last lens. When Equation 6 is satisfied, the optical system (1000, 1100) can secure an appropriate BFL. In the first and second embodiments, Equation 6 can preferably satisfy 0.2 < BFL / TTL < 0.3.

[0364]

[0365] [Mathematical Formula 7]

[0366] 20 degrees < Angle between upper and lower rays of Full Field < 40 degrees

[0367] The point where the optical axis (OA) meets the image sensor (300) is the 0 Field, and the outermost edge region of the image sensor (300) is the 1 Field or Full Field. Referring to FIGS. 1 and FIGS. 11, among the three rays incident on the Full Field of the image sensor (300), the uppermost ray may be referred to as the upper ray, and the lowermost ray may be referred to as the lower ray. At this time, the greater the angle between the upper ray and the lower ray of the Full Field of the image sensor (300), the more advantageous it may be for securing a peripheral light ratio. The greater the peripheral light ratio, the brighter the image can be secured even in the outer region of the image sensor.

[0368] If the value is below the lower limit of Equation 7, there is a problem of the peripheral light ratio decreasing, and if the value exceeds Equation 7, there is a problem of the overall effective diameter increasing. When Equation 7 is satisfied, the optical system (1000, 1100) can secure a bright image even in the outer region of the entire image. In the first and second embodiments, Equation 7 can preferably satisfy 28 degrees < the angle between the upper and lower light rays of the Full Field < 35 degrees.

[0369]

[0370] [Mathematical Formula 8]

[0371] 1.7 < ΣIndex < 1.9

[0372] In Equation 8, ΣIndex is the average of the refractive indices of the first to sixth lenses (101 to 106, 201 to 206). If Equation 8 is satisfied, the number of lenses having a high refractive index included in the optical system (1000, 1100) can be increased to effectively control aberrations. In the first and second embodiments, Equation 8 can preferably satisfy 1.8 < ΣIndex < 1.85.

[0373]

[0374] [Mathematical Formula 9]

[0375] 0.3 < F4 / F3 < 1

[0376] In Equation 9, F4 is the focal length of the fourth lens (104, 204), and F3 is the focal length of the third lens (103, 203). When Equation 9 is satisfied, the focal lengths of the third lens (103, 203) and the fourth lens (104, 204), which are adjacent to the aperture (STOP) that has a significant influence within the optical system (1000, 1100), are appropriately designed so that the overall length of the optical system can be miniaturized. In the first and second embodiments, Equation 9 can preferably satisfy 0.5 < F4 / F3 < 0.8.

[0377]

[0378] [Mathematical Formula 10]

[0379] 1.5 < n4 < 1.7

[0380] In Equation 10, n4 is the refractive index of the fourth lens (104, 204). When Equation 10 is satisfied, the fourth lens (104, 204) has a high refractive index among the lenses of the optical system (1000, 1100), thereby minimizing chromatic aberration. In the first and second embodiments, Equation 10 can preferably satisfy 1.5 < n4 < 1.6.

[0381]

[0382] [Mathematical Formula 11]

[0383] 1.3 < F4 / F < 1.7

[0384] In Equation 11, F4 is the focal length of the fourth lens (104, 204), and F is the effective focal length of the optical system. If Equation 11 is satisfied, aberration characteristics can be secured, and a stable optical system can be formed by forming a smooth optical path at a short TTL. If it is below the lower limit of Equation 11, the effective aperture or TTL of the lenses becomes longer, which may cause a problem where the imaging lens system becomes large. If it exceeds the upper limit of Equation 11, the influence of the fourth lens (104, 204) placed adjacent to the aperture (STOP) is reduced in the entire optical system, and it is necessary to increase the refractive power of the lenses, which makes it difficult to correct spherical aberration or distortion aberration. In the first and second embodiments, Equation 11 can preferably satisfy 1.5 < F4 / F < 1.7.

[0385]

[0386] [Mathematical Formula 12]

[0387] 0.01 < CG4 / TTL < 0.2

[0388] In Equation 12, CG4 is the center distance between the fourth lens (104, 204) and the fifth lens (105, 205), and TTL is the distance (mm) from the center of the first surface (S1) of the first lens (101, 201) to the top surface of the image sensor (500) along the optical axis (OA). When Equation 12 is satisfied, a light path is established in which light emitted from the first lens (101, 201), which is positioned closest to the object side, is incident on 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, Equation 12 can preferably satisfy 0.05 < CG4 / TTL < 0.15.

[0389]

[0390] [Mathematical Formula 13]

[0391] 0.2 < CG4 / CG1 < 1.5

[0392] In Equation 13, CG4 is the center distance between the fourth lens (104, 204) and the fifth lens (105, 205), and CG1 is the center distance between the first lens (101, 201) and the second lens (102, 202). When Equation 13 is satisfied, the spacing between adjacent lenses within the optical system (1000, 1100) is appropriately designed to establish a smooth light path, and the optical system can have good optical performance at the set angle of view and focal length. In addition, the spacing between the fourth lens (104, 204) and the fifth lens (105, 205) adjacent to the image sensor (300) is appropriately designed to have a high peripheral light ratio. In the first and second embodiments, Equation 13 can preferably satisfy 0.3 < CG4 / CG1 < 1.4.

[0393]

[0394] [Mathematical Formula 14]

[0395] 0.5 < |L4R2 / L5R1| < 2.5

[0396] In Equation 14, L4R2 is the radius of curvature of the sensor side (8th surface (S8)) of the 4th lens (104, 204), and L5R1 is the radius of curvature of the object side (9th surface (S9)) of the 5th lens (105, 205). When Equation 14 is satisfied, the radius of curvature of the opposing surfaces of the 4th lens (104, 204) and the 5th lens (105, 205) adjacent to the image sensor (300) is increased to form a gentle light path, and a miniaturized optical system can be realized by appropriately designing the gap between the 4th lens (104, 204) and the 5th lens (105, 205). In the 1st and 2nd embodiments, Equation 14 can preferably satisfy 0.8 < |L4R2 / L5R1| < 2.2.

[0397]

[0398] [Mathematical Formula 15]

[0399] 1.2 < L1R1 / L1R2 < 2

[0400] In Equation 15, L1R1 is the radius of curvature of the object side (first surface (S1)) of the first lens (101, 201), and L1R2 is the radius of curvature of the sensor side (second surface (S2)) of the first lens (101, 201). When Equation 15 is satisfied, the shape of the first lens (101, 201) positioned closest to the object side is appropriately designed to set a light path for light emitted from the first lens (101, 201) to be incident on the remaining lens, and the optical system can have good optical performance at the set angle of view and focal length. In the first and second embodiments, Equation 15 can preferably satisfy 1.3 < L1R1 / L1R2 < 1.7.

[0401]

[0402] [Mathematical Formula 16]

[0403] 0.1 < F / TTL < 0.3

[0404] In Equation 16, F represents the effective focal length of the optical system, and TTL (Total track length) represents the distance (mm) along the optical axis (OA) from the vertex of the first surface (S1) of the first lens (101, 201) to the top surface of the image sensor (300). Accordingly, an optical system for a driver assistance system can be provided. When Equation 16 is satisfied, the optical system (1000, 1100) can have an appropriate focal length within the set TTL range and can form an image while maintaining an appropriate focal length even as the temperature changes from low to high temperatures. If it is below the lower limit of Equation 16, it is necessary to increase the refractive power of the lenses, making it difficult to correct spherical aberration or distortion aberration; if it exceeds the upper limit of Equation 16, the effective diameter or TTL of the lenses becomes longer, which may cause a problem where the imaging lens system becomes larger. In the first and second embodiments, mathematical formula 16 can preferably satisfy 0.2 < F / TTL < 0.3.

[0405]

[0406] [Mathematical Formula 17]

[0407] 3 < TTL / ImgH < 5

[0408] In Equation 17, TTL (Total track length) refers to the distance (mm) along the optical axis (OA) from the vertex of the first surface (S1) of the first lens (101, 201) to the top surface of the image sensor (300), and ImgH refers to the maximum diagonal length of the image sensor (300). When Equation 17 is satisfied, the optical system (1000, 1100) can have a TTL for application to the vehicle image sensor (300), thereby providing improved image quality. If it is below the lower limit of Equation 17, it is necessary to increase the refractive power of the lenses, making it difficult to correct spherical aberration or distortion aberration; if it exceeds the upper limit of Equation 17, the effective aperture or TTL of the lenses becomes longer, which may cause a problem where the imaging lens system becomes larger. In the first and second embodiments, mathematical formula 17 can preferably satisfy 3.5 < TTL / ImgH < 4.

[0409]

[0410] [Mathematical Formula 18]

[0411] 20 < ΣAbb / ΣIndex < 25

[0412] In Equation 18, ΣAbb represents the sum of the Abbe numbers of each of the multiple lenses, and ΣIndex represents the sum of the refractive indices of each of the multiple lenses at the d-line. When Equation 18 is satisfied, the optical system (1000, 1100) can have improved aberration characteristics and resolution. By setting the sum of the Abbe numbers and the sum of the refractive indices of the lenses in Equation 18, optical characteristics can be controlled. In the first and second embodiments, Equation 18 can preferably satisfy 21 < ΣAbb / ΣIndex < 25.

[0413]

[0414] [Mathematical Formula 19]

[0415] 0.5 < F / EPD < 1.5

[0416] In Equation 19, F is the effective focal length of the optical system, and EPD represents the diameter of the entrance pupil (effective aperture). When Equation 19 is satisfied, an image with 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, Equation 19 can preferably satisfy 0.6 < F / EPD < 0.8.

[0417]

[0418] [Mathematical Formula 20]

[0419] 0.1 < BFL / TTL < 0.3

[0420] In Equation 20, BFL represents the optical axis distance from the image sensor (300) to the center of the sensor side of the last lens, and TTL (Total track length) represents the distance (mm) along the optical axis (OA) from the vertex of the first surface (S1) of the first lens (101, 201) to the top surface of the image sensor (300). When Equation 20 is satisfied, the optical system (1000, 1100) can have a set angle of view and an appropriate focal length, and an optical system for vehicles can be provided. In addition, the optical system (1000, 1100) can minimize the gap between the last lens and the image sensor (300), thereby having good optical characteristics at the periphery of the angle of view (FOV). In the first and second embodiments, Equation 20 preferably satisfies 0.2 < BFL / TTL < 0.3.

[0421]

[0422] [Mathematical Formula 21]

[0423] 0.5 < CT_Max / CG_Max < 1

[0424] In Equation 21, CT_Max is the maximum center thickness among the lenses, and CG_Max is the maximum distance between adjacent lenses. If Equation 21 is satisfied, the optical system can have good optical performance at the focal length at the set angle of view and can reduce TTL. In the first and second embodiments, Equation 21 can preferably satisfy 0.6 < CT_Max / CG_Max < 0.8.

[0425]

[0426] [Mathematical Formula 22]

[0427] 1 < CA_max / CA_min < 1.5

[0428] In Equation 22, CA_max represents the maximum effective diameter among the object sides and sensor sides of the lenses, and CA_Min represents the minimum effective diameter among the object sides and sensor sides of the lenses. When Equation 22 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, Equation 22 preferably satisfies 1.2 < CA_max / CA_min < 1.5.

[0429]

[0430] [Mathematical Formula 23]

[0431] 0.3 < ΣCG / ΣCT < 1

[0432] In Equation 23, ΣCG is the sum of the spacing between adjacent lenses, and ΣCT is the sum of the center thicknesses of the lenses. If Equation 23 is satisfied, the optical system can have good optical performance at a focal length at a set angle of view and can reduce TTL. In the first and second embodiments, Equation 23 can preferably satisfy 0.5 < ΣCG / ΣCT < 0.7.

[0433]

[0434] [Mathematical Formula 24]

[0435] 0.1 < CG1 / ΣCG < 1

[0436] In Equation 24, CG1 is the center distance between the first lens (101, 201) and the second lens (102, 202), and ΣCG is the sum of the distances between adjacent lenses. When Equation 24 is satisfied, a light path is established in which light emitted from the first lens (101, 201), which is positioned closest to the object side, is incident on 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, Equation 24 can preferably satisfy 0.2 < CG1 / ΣCG < 0.8.

[0437]

[0438] [Mathematical Formula 25]

[0439] 40 < HFOV < 50

[0440] In mathematical formula 25, HFOV represents the horizontal angle of view (Degree) of the optical system (1000, 1100) and can provide an angle of view suitable for an optical system for vehicles. In the first and second embodiments, preferably, 44 < HFOV < 48 can be satisfied.

[0441]

[0442] [Mathematical Formula 26]

[0443] 2.5 < TTL / CA_max < 3

[0444] In Equation 26, TTL (Total track length) represents the distance (mm) along the optical axis (OA) from the vertex of the first surface (S1) of the first lens (101, 201) to the top surface of the image sensor (300), and CA_max represents the maximum effective diameter among the object sides and sensor sides of the lenses. When Equation 26 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, Equation 26 can preferably satisfy 2.6 < TTL / CA_max < 2.9.

[0445]

[0446] [Mathematical Formula 27]

[0447] 30 < TTL < 40

[0448] In Equation 27, TTL (Total track length) refers to the distance (mm) along the optical axis (OA) from the center of the first surface (S1) of the first lens (101, 201) to the top surface of the image sensor (300). If Equation 27 is satisfied, a suitable automotive optical system can be provided. In the first and second embodiments, Equation 27 can preferably satisfy 36 < TTL < 38.

[0449]

[0450] [Mathematical Formula 28]

[0451] 9 < ImgH < 12

[0452] In mathematical formula 28, ImgH represents the maximum diagonal length of the image sensor (300). Mathematical formula 28 can set the diagonal size of the image sensor (300) and can provide an optical system having the size of a vehicle image sensor. In the first and second embodiments, mathematical formula 28 can preferably satisfy 10 < ImgH < 11.

[0453]

[0454] [Mathematical Formula 29]

[0455] 10 < BFL < 12

[0456] In Equation 29, BFL is the optical axis distance from the image sensor (300) to the center of the sensor side of the last lens. If Equation 29 is satisfied, installation space for the filter (400) and cover glass can be secured, and the assembly of components and coupling reliability can be improved through the gap between the image sensor (300) and the last lens. If BFL is less than the range of Equation 29, some light proceeding to the image sensor may not be transmitted to the image sensor, which may cause a decrease in resolution. If BFL exceeds the range of Equation 29, stray light may be introduced, which may degrade the aberration characteristics of the optical system. In the first and second embodiments, Equation 29 preferably satisfies 10 < BFL < 11.

[0457]

[0458] [Mathematical Formula 30]

[0459] 8 < F < 12

[0460] Equation 30 can set the total focal length (F) to suit the automotive optical system. In the first and second embodiments, Equation 30 can satisfy 9 < F < 11.

[0461]

[0462] [Mathematical Formula 31]

[0463]

[0464] In Equation 31, Z represents Sag, which can mean the distance in the direction of the optical axis from any position on the aspherical surface to the vertex of the aspherical surface. Y represents the distance in the direction perpendicular to the optical axis from any position on the aspherical surface to the optical axis. c can represent the curvature of the lens, and K can represent the conic constant. Additionally, A, B, C, D, and E can represent the aspheric constants.

[0465]

[0466] The optical system (1000, 1100) according to the first and second embodiments may satisfy at least one or two of the mathematical formulas 1 to 31. In this case, the optical system (1000, 1100) may have improved optical characteristics. Specifically, when the optical system (1000, 1100) satisfies at least one or two of the mathematical formulas 1 to 31, the optical system (1000, 1100) may have improved resolution and may improve aberration and distortion characteristics. In addition, the optical system (1000, 1100) may secure a Back Focal Length (BFL) for applying a vehicle image sensor (300), compensate for the degradation of optical characteristics due to temperature changes, and minimize the gap between the last lens and the image sensor (300), thereby having good optical performance in the center and periphery of the field of view (FOV).

[0467]

[0468] Table 7 shows the result values ​​for the above-described Equations 1 to 30 in the optical system (1000, 1100) of the embodiment. Referring to Table 7, it can be seen that the optical system (1000, 1100) satisfies at least one, two or more, or three or more of Equations 1 to 30. Specifically, it can be seen that the optical system (1000, 1100) according to the embodiment satisfies all of Equations 1 to 30. 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).

[0469]

[0470] Mathematical Formula Example 1 Example 2 Example 11 < CA_max*F-number / ImgH < 21.884 1.7962|positive power number of lenses-negative power number of lenses| ≤ 10030 < |BFL(low temperature)-BFL(high temperature)| < 0.10.041 0.03241 < |F1| / F < 32.6592.11950.2 < CA_max / TTL < 0.50.3650.34860.1 < BFL / TTL < 0.40.2790.278720 degree < Angle between upper and lower rays of Full Field < 40 degree 30.220 34.32981.7 < ΣIndex < 1.91.8131.81090.3 < F4 / F3 < 10.7090.556101.5 < n4 < 1.71.5521.595111.3 < F4 / F < 1.71.6701.536120.01 < CG4 / TTL < 0.20.0610.117130.2 < CG4 / CG1 < 1.50.3161.395140.5 < |L4R2 / L5R1| < 2.50.9342.121151.2 < L1R1 / L1R2 < 21.4441.658160.1 < F / TTL < 0.30.2880.285173 < TTL / ImgH < 53.6833.6831820 < ΣAbb / ΣIndex < 2524.14222.576190.5 < F / EPD < 1.50.7000.700200.1 < BFL / TTL < 0.30.2790.278210.5 < CT_Max / CG_Max < 10.6160.716221 < CA_max / CA_min < 1.51.4361.392230.3 < ΣCG / ΣCT < 10.5900.626240.1 < CG1 / ΣCG < 10.7190.3022540 < HFOV < 5046.10046.400262.5 < TTL / CA_max < 32.7372.8712730 < TTL < 4037.90037.900289 < ImgH < 1210.2910.292910 < BFL < 1210.59310.532308 < F < 1210.90010.800.

[0471] FIG. 21 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. 21, a vehicle camera system according to an embodiment of the invention includes an image generation unit (11), a first information generation unit (12), a second information generation unit (21, 22, 23, 24, 25, 26), and a control unit (14). The image generation unit (11) may include at least one camera module (31) disposed in the vehicle and may generate a front image of the vehicle or an interior image of the vehicle by photographing the front of the vehicle and / or the driver. The image generation unit (11) may generate an image of the vehicle's surroundings by photographing the vehicle's surroundings in one or more directions as well as the front of the vehicle using the camera module (31). Here, the front image and the surrounding image may be digital images and may include color images, black and white images, and infrared images. Additionally, the front image and the surrounding image may include still images and video images. The image generation unit (11) provides the driver image, the front image, and the surrounding image to the control unit (14). Subsequently, the first information generation unit (12) may include at least one radar or / and camera placed on the vehicle and generates first detection information by detecting the front of the vehicle. Specifically, the first information generation unit (12) is placed on the vehicle and generates first detection information by detecting the position and speed of vehicles located in front of the vehicle, the presence and location of pedestrians, etc.

[0472] By using the first detection information generated by the first information generation unit (12), the distance between the vehicle and the vehicle in front can be controlled to be maintained at a constant level, and the stability of vehicle operation can be enhanced in specific cases that are pre-set, such as when the driver wants to change the driving lane of the vehicle or when reverse parking. The first information generation unit (12) provides the first detection information to the control unit (14). The second information generation unit (21, 22, 23, 24, 25, 26) generates second detection information by detecting each side of the vehicle based on the front image generated by the image generation unit (11) and the first detection information generated by the first information generation unit (12). Specifically, the second information generation unit (21, 22, 23, 24, 25, 26) may include at least one radar or / and camera placed on the vehicle, and may detect the position and speed of vehicles located on the side of the vehicle or capture images. Here, the second information generating unit (21, 22, 23, 24, 25, 26) can be positioned at the front corners, side mirrors, and rear center and rear corners of the vehicle, respectively.

[0473] At least one information generating unit among such vehicle camera systems may be equipped with an optical system and a camera module having the same as described in the embodiment disclosed above, and may provide to or process information obtained through the front, rear, each side, or corner area of ​​the vehicle to protect the vehicle and objects from autonomous driving or surrounding safety.

[0474] The optical system of the camera module according to an embodiment of the invention can be mounted in multiple units within a vehicle to comply with safety regulations, enhance autonomous driving functions, and increase convenience. Furthermore, the optical system of the camera module is applied within the vehicle as a component for control, such as a Lane Keeping Assistance System (LKAS), Lane Departure Warning System (LDWS), and Driver Monitoring System (DMS). Such a vehicle camera module can achieve stable optical performance even with changes in ambient temperature and provides a cost-competitive module, thereby ensuring the reliability of vehicle components.

[0475]

[0476] 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 only one embodiment. Furthermore, the features, structures, effects, etc. exemplified in each embodiment may be combined or modified and implemented in other embodiments by a person skilled in the art to which the embodiments belong. Therefore, details regarding such combinations and modifications should be interpreted as being included within the scope of the present invention.

[0477] Furthermore, although the invention has been described above with reference to embodiments, this is merely illustrative and does not limit the invention. Those skilled in the art will understand that various modifications and applications not exemplified above are possible within the scope of the essential characteristics of the embodiments. For example, each component specifically shown in the embodiments may be modified and implemented. Differences related to such modifications and applications should be interpreted as being included within the scope of the invention as defined in the appended claims.

Claims

1. Includes first to sixth lenses arranged along the optical axis, and The first lens above has a negative (-) refractive power, and The second lens above has a negative (-) refractive power, and The above fifth lens has a negative (-) refractive power, and The above-mentioned sixth lens has a positive (+) refractive power, and An optical system in which the lens surface having the largest absolute value of the radius of curvature among the lens surfaces of the first to sixth lenses is the sensor side of the fourth lens or the object side of the fifth lens.

2. In Paragraph 1, The optical system in which the lens surface having the smallest absolute value of the radius of curvature among the lens surfaces of the first to sixth lenses is the sensor side of the first lens.

3. In Paragraph 1, The refractive index of the fifth lens is greater than the refractive index of the sixth lens, and An optical system in which the Abbe number of the fifth lens is smaller than the Abbe number of the sixth lens.

4. In Paragraph 1, An optical system in which the absolute value of the focal length of the fourth lens is smaller than the absolute value of the focal lengths of the first to third lenses.

5. In Paragraph 1, In the above optical axis, the third lens has a meniscus shape that is convex toward the sensor side, and The fourth lens on the above optical axis is an optical system having a shape that is convex on both sides.

6. In Paragraph 1, The above third lens has a positive (+) refractive power, and The above-mentioned fourth lens is an optical system having positive (+) refractive power.

7. In any one of paragraphs 1 through 6, An optical system satisfying the following condition. <Condition> 30 < TTL < 40 (In the above conditional equation, TTL refers to the distance from the object side of the first lens to the top surface of the image sensor along the optical axis.) 8. In any one of paragraphs 1 through 6, An optical system satisfying the following condition. <Condition> 3 < TTL / ImgH < 5 (In the above conditional equation, TTL refers to the distance from the object side of the first lens to the top surface of the image sensor along the optical axis, and ImgH refers to the maximum diagonal length of the image sensor.) 9. Includes first to sixth lenses arranged along the optical axis, and The first lens above has a negative (-) refractive power, and The second lens above has a negative (-) refractive power, and The above third lens has a positive (+) refractive power, and The above-mentioned fourth lens has a positive (+) refractive power, and An optical system in which the lens surface having the largest absolute value of the radius of curvature among the lens surfaces of the first to sixth lenses is the sensor side of the fourth lens or the object side of the fifth lens.

10. In Paragraph 9, At the above optical axis, the fourth lens is convex on both sides, and The optical system in which the fifth lens on the above optical axis has a meniscus shape that is convex toward the object.

Images