Optical system and camera module

Abstract

An optical system according to an embodiment of the present invention comprises, in sequence from an object side to a sensor side: a first lens; a second lens; a third lens having negative (-) refractive power; a fourth lens having negative (-) refractive power; a fifth lens having positive (+) refractive power; and a sixth lens having positive (+) refractive power; a seventh lens; and an eighth lens having positive (+) refractive power, wherein the second lens has the highest refractive index among the first to eighth lenses.

Description

Optical system and camera module

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

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

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

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

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

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

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

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

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

[0010] In order to solve the above technical problem, an optical system according to an embodiment of the present invention includes, in order from an object side to a sensor side, a first lens; a second lens; a third lens having a negative (-) refractive power; a fourth lens having a negative (-) refractive power; a fifth lens having a positive (+) refractive power; a sixth lens having a positive (+) refractive power; a seventh lens; and an eighth lens having a positive (+) refractive power, wherein among the first to eighth lenses, the refractive index of the second lens is the greatest.

[0011] The second lens may be made of glass, and the third lens may be made of plastic.

[0012] The first lens and the seventh lens may have negative (-) refractive power, and the second lens may have positive (+) refractive power.

[0013] The distance between the first lens and the second lens on the optical axis may be greater than the distance between the fifth lens and the sixth lens.

[0014] Among the first to eighth lenses, the absolute value of the focal length of the fourth lens may be the largest.

[0015] The distance between the third lens and the fourth lens on the optical axis may be greater than the distance between the seventh lens and the eighth lens.

[0016] A first lens group including the first to fifth lenses and a second lens group including the sixth to eighth lenses are included, and a composite focal length of the first lens group may be smaller than a composite focal length of the second lens group.

[0017] A first lens group including the first to fifth lenses and a second lens group including the sixth to eighth lenses are included, and the sign of the composite focal length of the first lens group and the sign of the composite focal length of the second lens group may be different.

[0018] A first lens group including the first to fifth lenses and a second lens group including the sixth to eighth lenses are included, and the absolute value of the difference between the absolute value of the composite focal length of the first lens group and the absolute value of the focal length of the second lens group can satisfy 1 or more and 5 or less.

[0019] The following condition can be satisfied. <Condition> 1.7 < n2 < 1.9 (In the above condition, n2 represents the refractive index of the second lens.)

[0020] The following condition can be satisfied. <Condition> 20 < v2 < 30 (In the above condition, v2 means the Abbe number of the second lens.)

[0021] The following condition can be satisfied. <Condition> 110 < FOV_H < 150 (In the above condition, FOV_H means the horizontal angle of view of the optical system.)

[0022] The following condition can be satisfied. <Condition> 8 < TTL / ImgH < 9 (In the above condition, TTL means the distance on the optical axis from the center of the object-side surface of the first lens to the upper surface of the image sensor, and ImgH means 1 / 2 of the maximum diagonal length of the image sensor.)

[0023] In order to solve the above technical problem, an optical system according to another embodiment of the present invention includes, in order from the object side to the sensor side, a first lens; a second lens; a third lens having negative (-) refractive power; a fourth lens having negative (-) refractive power; a fifth lens; a sixth lens; a seventh lens having negative (-) refractive power; and an eighth lens having positive (+) refractive power, and a distance between the first lens and the second lens on the optical axis may be greater than a distance between the fifth lens and the sixth lens.

[0024] An aperture is arranged between the fifth lens and the sixth lens, and the fifth lens is made of glass and may have positive (+) refractive power.

[0025] Among the first to eighth lenses, the refractive index of the second lens may be the highest.

[0026] The first lens and the second lens may be made of glass, and the sixth to eighth lenses may be made of plastic.

[0027] Among the first to seventh lenses, the absolute value of the focal length of the fourth lens may be the largest.

[0028] A first lens group including the first to fifth lenses and a second lens group including the sixth to eighth lenses are included, and a composite focal length of the first lens group may be smaller than a composite focal length of the second lens group.

[0029] A first lens group including the first to fifth lenses and a second lens group including the sixth to eighth lenses are included, and the absolute value of the difference between the absolute value of the composite focal length of the first lens group and the absolute value of the focal length of the second lens group can satisfy 1 or more and 5 or less.

[0030] An optical system and camera module according to an embodiment may have improved optical characteristics. Specifically, in the optical system according to an embodiment, a plurality of lenses may have set thicknesses, refractive powers, and spacings from adjacent lenses. Accordingly, the optical system and camera module according to the embodiment may have improved MTF characteristics, aberration control characteristics, resolution characteristics, etc. within a set field of view range, and may have good optical performance in the periphery of the field of view.

[0031] In addition, the optical system and camera module according to the embodiment can have good optical performance in a low temperature to high temperature range (-40℃ to 105℃). Specifically, a plurality of lenses included in the optical system can have set materials, refractive powers, and refractive indices. Accordingly, when the refractive index of each lens changes according to a temperature change and the focal length of each lens changes due to this, mutual compensation can be made by the plastic lens and the glass lens. That is, the optical system can effectively perform refractive power distribution in a low temperature to high temperature range, and can prevent or minimize changes in optical characteristics in a low temperature to high temperature range. Therefore, the optical system and camera module according to the embodiment can maintain improved optical characteristics in various temperature ranges.

[0032] Furthermore, the optical system and camera module according to the embodiment can satisfy the set angle of view and implement excellent optical characteristics through a combination of plastic and glass lenses. This allows the optical system to provide a slimmer vehicle camera module. Accordingly, the optical system and camera module can be used in various applications and devices, and can maintain excellent optical characteristics even in harsh temperature environments, such as when exposed to the exterior of a vehicle or in the high temperatures of a vehicle interior during the summer.

[0033] FIG. 1 is a side cross-sectional view of an optical system and a camera module having the same according to the first embodiment of the present invention.

[0034] Figure 2 is a table showing the values ​​of the aspherical coefficient and the conic constant (k) of each lens surface in the optical system according to the first embodiment.

[0035] Figure 3 is a table showing the thickness of each lens and the spacing between adjacent lenses in the optical system according to the first embodiment.

[0036] Fig. 4 is a table showing the Sag values ​​of each lens surface in the optical system according to the first embodiment.

[0037] Fig. 5 is a table showing the slope angle values ​​of each lens surface in the optical system according to the first embodiment.

[0038] Fig. 6 is a graph showing data on the diffraction MTF (Modulation Transfer Function) at room temperature of the optical system according to the first embodiment of the present invention.

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

[0040] Fig. 8 is a graph showing data on the diffraction MTF at low temperatures of the optical system according to the first embodiment.

[0041] Fig. 9 is a graph showing data on aberration characteristics at low temperatures of the optical system according to the first embodiment.

[0042] Fig. 10 is a graph showing data on the diffraction MTF at high temperatures of the optical system according to the first embodiment.

[0043] Fig. 11 is a graph showing data on aberration characteristics at high temperatures of an optical system according to the first embodiment.

[0044] Fig. 12 is a side cross-sectional view of an optical system and a camera module having the same according to the second embodiment.

[0045] Fig. 13 is a table showing the values ​​of the aspherical coefficient and the conic constant (k) of each lens surface in the optical system according to the second embodiment.

[0046] Fig. 14 is a table showing the thickness of each lens and the spacing between adjacent lenses in the optical system according to the second embodiment.

[0047] Fig. 15 is a table showing the Sag values ​​of each lens surface in the optical system according to the second embodiment.

[0048] Fig. 16 is a table showing the slope angle values ​​of each lens surface in the optical system according to the second embodiment.

[0049] Fig. 17 is a graph showing data on the diffraction MTF (Modulation Transfer Function) at room temperature of the optical system according to the second embodiment.

[0050] Fig. 18 is a graph showing data on the aberration characteristics of the optical system according to the second embodiment at room temperature.

[0051] Fig. 19 is a graph showing data on the diffraction MTF at low temperatures of the optical system according to the second embodiment.

[0052] Fig. 20 is a graph showing data on aberration characteristics at low temperatures of an optical system according to the second embodiment.

[0053] Fig. 21 is a graph showing data on the diffraction MTF at high temperatures of the optical system according to the second embodiment.

[0054] Fig. 22 is a graph showing data on aberration characteristics at high temperatures of an optical system according to the second embodiment.

[0055] Fig. 23 is a side cross-sectional view of an optical system and a camera module having the same according to the third embodiment.

[0056] Fig. 24 is a table showing the values ​​of the aspherical coefficient and the conic constant (k) of each lens surface in the optical system according to the third embodiment.

[0057] Fig. 25 is a table showing the thickness of each lens and the spacing between adjacent lenses in the optical system according to the third embodiment.

[0058] Fig. 26 is a table showing the Sag values ​​of each lens surface in the optical system according to the third embodiment.

[0059] Fig. 27 is a table showing the slope angle values ​​of each lens surface in the optical system according to the third embodiment.

[0060] Fig. 28 is a graph showing data on the diffraction MTF (Modulation Transfer Function) at room temperature of the optical system according to the third embodiment.

[0061] Fig. 29 is a graph showing data on the aberration characteristics of the optical system according to the third embodiment at room temperature.

[0062] Fig. 30 is a graph showing data on the diffraction MTF at low temperatures of the optical system according to the third embodiment.

[0063] Fig. 31 is a graph showing data on aberration characteristics at low temperatures of an optical system according to the third embodiment.

[0064] Fig. 32 is a graph showing data on the diffraction MTF at high temperatures of the optical system according to the third embodiment.

[0065] Figure 33 is a graph showing data on aberration characteristics at high temperatures of an optical system according to the third embodiment.

[0066] FIG. 34 is an example of a vehicle having an optical system according to an embodiment of the invention.

[0067] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings.

[0068] However, the technical idea of ​​the present invention is not limited to some of the embodiments described, but can be implemented in various different forms, and within the scope of the technical idea of ​​the present invention, one or more of the components between the embodiments can be selectively combined or substituted for use.

[0069] In addition, terms (including technical and scientific terms) used in this embodiment may be interpreted as having a meaning that can be generally understood by a person of ordinary skill in the technical field to which this embodiment belongs, unless explicitly and specifically defined and described, and terms that are commonly used, such as terms defined in a dictionary, may be interpreted in consideration of the contextual meaning of the relevant technology.

[0070] Additionally, the terms used in this embodiment are for the purpose of describing the embodiments and are not intended to limit the present invention.

[0071] In this specification, the singular may also include the plural unless specifically stated otherwise in the phrase, and when it is described as “A and / or at least one (or more) of B, C”, it may include one or more of all combinations that can be combined with A, B, C.

[0072] Additionally, in describing the components of this embodiment, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only intended to distinguish the components from other components, and are not intended to limit the nature, order, or sequence of the components.

[0073] And, when a component is described as being 'connected', 'coupled', or 'connected' to another component, it may include not only cases where the component is 'connected', 'coupled', or 'connected' directly to the other component, but also cases where the component is 'connected', 'coupled', or 'connected' by another component between the component and the other component.

[0074] Additionally, when described as being formed or arranged "above" or "below" each component, "above" or "below" includes not only cases where the two components are in direct contact with each other, but also cases where one or more other components are formed or arranged between the two components. Furthermore, when expressed as "above" or "below," the meaning may include not only the upward direction but also the downward direction based on one component.

[0075] In the description of the invention, the "object side" may mean a surface of the lens facing the object side with respect to the optical axis (OA), and the "sensor side" may mean a surface of the lens facing the imaging surface (image sensor) with respect to the optical axis. The "object side" may be the "object side," and the "sensor side" may be the "image side." A convex surface of a lens may mean a convex shape in the optical axis or the paraxial region, and a concave surface of a lens may mean a concave shape in the optical axis or the paraxial region. The radius of curvature, the center thickness, and the optical axis spacing between lenses described in the table for lens data may mean values ​​(unit: mm) in the optical axis. The vertical direction may mean a direction perpendicular to the optical axis, and the end of a lens or lens surface may mean the end of an effective area of ​​a lens through which incident light passes. The size of the effective diameter of the lens surface may have a measurement error of up to ±0.4 mm depending on the measurement method, etc. The above-mentioned near-axis region refers to a very narrow region near the optical axis, and is a region where the distance that a light ray falls from the optical axis (OA) is almost 0. Hereinafter, the meaning of the optical axis may include the center of each lens or a very narrow region near the optical axis.

[0076] The effective diameter may be the diameter of the effective area where effective light is incident on each lens. The effective diameter is the length in the direction (X, Y) orthogonal to the optical axis, and is the average of the effective diameter on the object side of each lens and the effective diameter on the sensor side. "Diameter of the lens surface" may mean "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 flange of the lens is not illustrated in the drawing, the flange may be a portion that protrudes perpendicular to the optical axis from the side of the lens so that the lens is coupled to the barrel. Effective light may not be incident on the flange. A spacer may be additionally arranged between the flanges of different lenses so that the lenses are coupled to the barrel.

[0077] Each of the lenses may include an effective area and an ineffective area. The effective area may be an area through which light incident on each of the lenses passes. In other words, the effective area may be defined as an effective area or effective diameter through which the incident light is refracted to implement optical characteristics. The ineffective area may be arranged around the periphery of the effective area. The ineffective area may be an area through which effective light is not incident on a plurality of lenses. In other words, the ineffective area may be an area unrelated to the optical characteristics. In addition, an end of the ineffective area may be an area fixed to a lens barrel or the like that accommodates the lens.

[0078]

[0079] As shown in FIGS. 1, 12, and 23, the optical systems (1000, 1100, and 1200) according to the first to third embodiments of the present invention may include seven or more lenses. The optical systems (1000, 1100, and 1200) and the camera modules 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 from glass or plastic, and the coefficient of linear expansion of glass material is lower than that of plastic material. Accordingly, glass lenses are employed to suppress changes in the focal imaging position due to temperature changes. However, glass lenses are more expensive than plastic lenses, and there is a problem that it is difficult to meet the demand for low cost. Therefore, the lenses in the optical systems (1000, 1100, and 1200) are required to have a mixed configuration of glass lenses and plastic lenses. By employing these plastic lenses, the optical system (1000, 1100, 1200) can be made lighter and cheaper by reducing the thickness of the plastic lenses, and the plastic lenses can provide excellent correction for various aberrations such as spherical aberration and chromatic aberration. In addition, since the plastic lenses can provide aspherical lenses, distortion in the peripheral areas can be minimized.

[0080] The optical system (1000, 1100, 1200) may include n lenses, where the n-th lens may be the last lens adjacent to the image sensor (400), and the (n-1)-th lens may be the lens closest to the last lens. n is an integer greater than or equal to 7, for example, 7 to 9. The n lenses may have a ratio of glass lenses to plastic lenses in the range of 2:6 to 3:5.

[0081] Within the optical system (1000, 1100, 1200), at least one lens closest to the object may be made of glass. Two or fewer lenses, for example, two lenses, closest to the object may be made of glass. Since glass lenses exhibit a smaller rate of expansion and contraction due to temperature changes than plastic lenses, the glass lenses may be positioned in an area adjacent to the outside of the lens barrel.

[0082] At least one lens disposed adjacent to the stop within the optical system (1000, 1100, 1200) may be made of glass. The lens disposed closest to the stop on the object side of the stop may be made of glass. Since the lens disposed adjacent to the stop has a large influence in the optical system (1000, 1100, 1200), the glass lens may be disposed so that the rate of change in contraction and expansion due to temperature changes is small.

[0083] At least one lens closest to the image sensor (400) within the optical system (1000, 1100, 1200) may be made of plastic. For example, at least two lenses closest to the image sensor (400) may be made of plastic, and preferably, at least two lenses adjacent to the image sensor (400) may be made of plastic. That is, since the n-th and n-1-th lenses in the optical system (1000, 1100, 1200) are arranged as plastic lenses, various aberrations can be corrected for the light incident on the image sensor (400).

[0084] Within the optical system (1000, 1100, 1200), plastic lenses can be arranged in series, and glass lenses can be arranged in series. Within the optical system (1000, 1100, 1200), plastic lenses can be arranged between glass lenses. Within the optical system (1000, 1100, 1200), glass lenses can be arranged between plastic lenses.

[0085]

[0086] Each lens (101-108, 201-208, 301-308) can have an object side surface and a sensor side surface. The optical system can have more lenses with aspherical sensor sides and aspherical object sides than the number of plastic lenses. The optical system can have fewer lenses with spherical sensor sides and spherical object sides than lenses with aspherical surfaces on both sides. The optical system (1000, 1100, 1200) has more aspherical lenses than spherical lenses, so it can correct various aberrations.

[0087] Among the lenses of the optical system (1000, 1100, 1200), the lens with the highest refractive index can be positioned adjacent to the object. The highest refractive index can be 1.7 or higher. The chromatic dispersion of light incident on the lens with the highest refractive index can be increased, and the center thickness can be made thinner than the edge thickness. In addition, since the lens with the highest refractive index is positioned on the object side, the radius of curvature of the second and subsequent lenses can be easily changed, and the center thickness can be increased.

[0088]

[0089] As shown in FIGS. 1, 12 and 23, the optical systems (1000, 1100, 1200) according to the first to third embodiments of the invention may include a plurality of lens groups (LG1, LG2). In detail, each of the plurality of lens groups (LG1, LG2) includes at least one lens. For example, the optical systems (1000, 1100, 1200) may include a first lens group (LG1) and a second lens group (LG2) that are sequentially arranged along the optical axis (OA) from the object side toward the image sensor (400). The optical systems (1000, 1100, 1200) may include n lenses, the n-th lens may be the last lens, and the (n-1)-th lens may be the lens closest to the last lens. n is an integer greater than or equal to 5, for example, 5 to 8.

[0090] The optical system (1000, 1100, 1200) may include a first lens group (LG1) which is a plurality of lenses arranged on the object side based on the aperture (STOP) and a second lens group (LG2) which is a plurality of lenses arranged on the sensor side based on the aperture (STOP). The number of lenses in each of the first lens group (LG1) and the second lens group (LG2) may be different. The number of lenses in the first lens group (LG1) may be greater than the number of lenses in the second lens group (LG2). Alternatively, the number of lenses in the first lens group (LG1) and the number of lenses in the second lens group (LG2) may be the same.

[0091] The first lens group (LG1) may include at least one lens. The first lens group (LG1) may have five or fewer lenses. The first lens group (LG1) may preferably have five lenses. The second lens group (LG2) may include three or more lenses. The second lens group (LG2) may have three lenses.

[0092] The composite focal length of the first lens group (LG1) can be defined as F_LG1, and the composite focal length of the second lens group (LG2) can be defined as F_LG2. The signs of F_LG1 and F_LG2 can be different from each other. F_LG1 can have a negative (-) value, and F_LG2 can have a positive (+) value. Through this, light can be spread from one of the two lens groups and then gathered from the other lens group. The difference between the absolute value of the composite focal length (F_LG1) of the first lens group (LG1) and the absolute value of the composite focal length (F_LG2) of the second lens group (LG2) can satisfy a range of 1 or more and 5 or less. When this is satisfied, the yield can be increased and the tolerance can be reduced when manufacturing the optical system (1000, 1100, 1200).

[0093] The aperture (STOP) is arranged between the fifth lens (105, 205, 305) and the sixth lens (106, 206, 306), and the first lens group (LG1) may include the first to fifth lenses (101-105, 201-205, 301-305), and the second lens group (LG2) may include the sixth to eighth lenses (106-108, 206-208, 306-308). The composite focal length of the first lens group (LG1) may have a negative (-) sign, and at least one focal length among the first lens (101, 201, 301), the third lens (103, 203, 303), and the fourth lens (104, 204, 304) may have the same focal length sign as the first lens group (LG1). In the first lens group (LG1), the Abbe number of the lens having the same sign as the sign of the composite focal length of the first lens group (LG1) may be 40 or more. The Abbe numbers of the first lens (101, 201, 301) and the third lens (102, 202, 303) may be 40 or more. Through this, aberration of light passing through each lens can be eliminated. However, the Abbe number of the second lens (102, 202, 302) having a small refractive power may be 40 or less as an exception.

[0094] The composite focal length of the second lens group (LG2) has a positive (+) sign, and at least one of the fifth lens (105, 205, 305), the sixth lens (106, 206, 306), and the eighth lens (108, 208, 308) may have the same focal length sign as that of the second lens group (LG2). The Abbe number of the lens in the second lens group (LG2) having the same sign as that of the composite focal length of the second lens group (LG2) may be 50 or more. The Abbe number of at least one of the fifth lens (105, 205, 305), the sixth lens (106, 206, 306), and the eighth lens (108, 208, 308) may be 40 or more. Through this, aberration of light passing through each lens can be eliminated. However, a lens having a relatively small refractive power may exceptionally have an Abbe number of 50 or less.

[0095]

[0096] Within the optical system (1000, 1100, 1200), the lens with the largest effective diameter can be placed closest to the object side. The effective diameter of the lens can increase and then decrease as it moves from the object side to the sensor side. The effective diameter of the lens can decrease and then increase as it moves from the object side to the sensor side. Through this, since the light incident on the optical system (1000, 1100, 1200) is structured to gather toward the optical axis and then move away from the optical axis again, the optical system (1000, 1100, 1200) can form a stable optical path.

[0097] The effective diameter may be the diameter of the effective area where effective light is incident on each lens. The effective diameter is the length in the direction (X, Y) orthogonal to the optical axis, and is the average of the effective diameter on the object side of each lens and the effective diameter on the sensor side. The "diameter of the lens surface" may mean the "effective diameter of the lens." The "diameter of the lens" may be the diameter of the entire lens including the flange portion of the lens in addition to the effective area of ​​the lens. Although the flanges of the lenses are not illustrated in FIGS. 1, 12, and 23, the flanges may be portions that protrude perpendicular to the optical axis from the side surfaces of the lenses so that the lenses are coupled to the barrel. The flanges may not receive effective light. A spacer may be additionally arranged between the flanges of different lenses so that the lenses are coupled to the barrel.

[0098] Each of the lenses (101-108, 201-208, 301-308) may include an effective area and an ineffective area. The effective area may be an area through which light incident on each of the lenses passes. In other words, the effective area may be defined as an effective area or effective diameter through which the incident light is refracted to implement optical characteristics. The ineffective area may be arranged around the periphery of the effective area. The ineffective area may be an area through which effective light is not incident from a plurality of lenses. In other words, the ineffective area may be an area unrelated to the optical characteristics. In addition, an end of the ineffective area may be an area fixed to a lens barrel or the like that accommodates the lens.

[0099] The edge thickness (ET1-ET8) of the lenses (101-108, 201-208, 301-308) may refer to the thickness at the end of the effective area. The edge thickness (ET1-ET8) of the lenses (101-108, 201-208, 301-308) may be set based on the lens surface with a larger effective area among the object-side and sensor-side surfaces of each lens.

[0100]

[0101] Within the optical system (1000, 1100, 1200), the TTL (Total top length) may be more than 5 times, for example, more than 6 times and less than 8 times, than Imgh. The TTL (Total track length) is the distance from the center of the object-side surface of the first lens to the top surface of the image sensor (400) on the optical axis (OA). Imgh is half the maximum diagonal length of the image sensor (400). Within the optical system (1000, 1100, 1200), the effective focal length (EFL) is provided to be more than 5 mm and less than 6 mm, and the horizontal field of view (FOV_H) is provided to be more than 110 and less than 150, so that the vehicle camera module may be provided as an optical system for monitoring the interior of a vehicle. For example, the optical system and the camera module according to the embodiment may be applied to a camera for an ADAS (Advanced Driving Assistance System) installed inside or outside a vehicle.

[0102] The optical system (1000, 1100, 1200) may have a TTL / Imgh condition of 8 or more and 9 or less, for example, 1.7 or more and 2 or less. By setting the TTL / Imgh value to 8.2 or more and 8.8 or less in the optical system (1000, 1100, 1200), a vehicle lens optical system can be provided. Accordingly, the optical system (1000, 1100, 1200) can provide an image without exaggeration or distortion in the formed image.

[0103]

[0104] The effective diameter of at least one plastic lens within the optical system (1000, 1100, 1200) may be smaller than the length of the image sensor (400). The effective diameter is the diameter or length of the effective area where light is incident. The length of the image sensor (400) is the maximum length of the diagonal in the direction orthogonal to the optical axis (OA). The number of lenses having an effective diameter larger than the length of the image sensor (400) within the optical system (1000, 1100, 1200) may be 10% or more and 20% or less, and the number of lenses having an effective diameter smaller than the length of the image sensor (400) may be 70% or more and 80% or less.

[0105]

[0106] The lens unit can be a mixture of glass and plastic lenses. The number of plastic lenses can be more than 70% of the total number of lenses, and can range from 65% to 85%. Accordingly, if more plastic lenses are placed within the camera module, the weight of the camera module can be reduced. The plastic material allows for easy polishing and processing, is resistant to external impacts, and is also price competitive and easy to secure. Furthermore, the plastic lenses can correct various aberrations, preventing deterioration of optical performance.

[0107] An embodiment of the invention can reduce the weight of a camera module, provide a lower manufacturing cost, suppress deterioration of optical characteristics due to temperature change, and allow various types of plastic lenses to replace glass lenses by further mixing plastic lenses into the optical system (1000, 1100, 1200). In addition, the lens surface, such as an aspherical surface or a free-form surface, can be easily polished and processed.

[0108]

[0109] The effective diameter of the lens closest to the object side within the lens unit may be larger than the effective diameter of the lens closest to the image sensor (400). 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 effective diameter size of each lens, the optical system (1000, 1100, 1200) can control the incident light to compensate for the deterioration of optical characteristics due to resolution and temperature change, improve chromatic aberration control characteristics, and improve the vignetting characteristics of the optical system (1000, 1100, 1200).

[0110] The lens unit may include a first lens (101, 201, 301), a second lens (102, 202, 302), a third lens (103, 203, 303), a fourth lens (104, 204, 304), a fifth lens (105, 205, 305), a sixth lens (106, 206, 306), a seventh lens (107, 207, 307), and an eighth lens (108, 208, 308), which are aligned from the object side toward the sensor side along the optical axis.

[0111]

[0112] The lens unit may be arranged in a camera module having an inner barrel on one side or the entire inner surface of a lens barrel. The lens unit may be arranged in a camera module having a plurality of inner barrels around different lenses of the lens barrel. The lens unit may be arranged in a camera module having a first inner barrel in contact with an outer surface of at least one lens of the lens barrel and a second inner barrel in contact with an outer surface of at least one lens. The lens unit may be arranged in a camera module having a plurality of inner barrels each of which is arranged between the outer surface of at least one lens or two or more lenses and the lens barrel. The lens unit may be arranged in a camera module in which the plurality of inner barrels have a material different from a material of the lens barrel.

[0113] Among the lenses constituting the lens unit, at least some of the glass lenses may be arranged in the lens barrel, and at least some of the plastic lenses may be arranged in the inner barrel arranged within the lens barrel. Through this, the optical system (1000, 1100, 1200) can maintain resolution according to temperature changes. The lens unit may be arranged in a camera module having different barrels to minimize decentering of lenses, such as plastic lenses, that expand according to temperature changes. The lens barrel in which the lens unit is arranged has a plurality of inner barrels within the lens barrel, thereby maintaining the resolution of the optical system according to temperature changes and suppressing deformation of the lenses. Therefore, the effective diameter of at least some of the glass lenses included in the lens unit may be smaller than the effective diameter of at least some of the plastic lenses.

[0114]

[0115] Within the lens unit, there may be one or more lenses, for example, two or more, larger than the average effective diameter of the plastic lenses. When the average effective diameter of the plastic lenses is PLca_Aver and the average effective diameter of the glass lenses is GLca_Aver, the condition of PLca_Aver < GLca_Aver may be satisfied. In addition, the condition of 1 < GLca_Aver / PLca_Aver < 2 may be satisfied. In addition, the relationship between the length of the image sensor (400) and the average effective diameter (PLca_Aver) of the plastic lenses may satisfy the condition of 1.2 < PLca_Aver / Imgh < 1.8. The difference between half the maximum diagonal length of the image sensor (400) and the effective diameter of the plastic lenses may not be large. Accordingly, by arranging a plastic lens with a small effective diameter adjacent to the image sensor (400), the plastic lenses may disperse color from the center to the periphery of the image sensor (400).

[0116]

[0117] The average effective diameter of the glass materials may be 11 mm or more, for example, in the range of 12 mm to 13 mm. The average effective diameter of the plastic material may be 7 mm or more, for example, in the range of 8 mm to 9 mm. The lens having the minimum effective diameter may be made of plastic, and the lens having the maximum effective diameter may be made of glass. The minimum effective diameter within the lens unit may be in the range of 6 mm to 7 mm, and the maximum effective diameter may be in the range of 17 mm to 20 mm. The plastic lens is designed to have a smaller effective diameter than the glass lens and is arranged so as not to touch the lens barrel, thereby minimizing changes in optical performance due to temperature changes. In addition, the optical system (1000, 1100, 1200) can improve resolution and chromatic aberration control characteristics by controlling incident light, and can improve vignetting characteristics of the optical system (1000, 1100, 1200).

[0118]

[0119] The optical system (1000, 1100, 1200) or camera module may include an image sensor (400). The image sensor (400) can detect light and convert it into an electrical signal. The image sensor (400) can detect light that sequentially passes through the lens unit. The image sensor (400) may include an element capable of detecting incident light, such as a charge-coupled device (CCD) or a complementary metal oxide semiconductor (CMOS).

[0120]

[0121] The optical system (1000, 1100, 1200) or camera module may include a filter (500). The filter (500) may be positioned between the last lens and the image sensor (400). The filter (500) may be positioned between the lens closest to the sensor side among the lenses of the lens unit and the image sensor (400). For example, the filter (500) may be positioned between the nth lens and the image sensor (400).

[0122] The cover glass is placed between the filter (500) and the image sensor (400), and protects the upper portion of the image sensor (400) and can prevent a decrease in the reliability of the image sensor (400). The cover glass can be removed. The cover glass may be a protective glass.

[0123] The filter (500) may include an infrared filter or an infrared cut-off filter (IR cut-off). The filter (500) may allow light of a set wavelength band to pass through and filter out light of a different wavelength band. When the filter (500) includes an infrared filter, it may block radiant heat emitted from external light from being transmitted to the image sensor (400). In addition, the filter (500) may transmit visible light and reflect infrared light.

[0124] The optical system (1000, 1100, 1200) according to the embodiment may include an aperture (Stop). The aperture can control the amount of light incident on the optical system (1000, 1100, 1200). In the lenses arranged between the object and the aperture, the effective diameter of the lens surface tends to increase from the object side to the aperture. In the lens surfaces arranged between the aperture and the sensor, the effective diameter of the lens surfaces tends to decrease from the aperture to the sensor side. The tendency for the effective diameter of the lens surfaces to increase or decrease does not only mean the case where the effective diameter of the lens surfaces increases or decreases. For example, it also includes the case where the effective diameter of the lens surfaces increases and then decreases from the aperture to the sensor side.

[0125]

[0126] In the optical systems (1000, 1100, 1200) of the first to third embodiments, the sum of the refractive indices of the lenses of the lens unit may be 10 or more, for example, in the range of 11 to 14, and the average of the refractive indices may be in the range of 1.5 to 1.7. The sum of the Abbe numbers of each of the lenses may be 340 or more, for example, in the range of 350 to 370, and the average of the Abbe numbers may be 50 or less, for example, in the range of 42 to 47. The sum of the central thicknesses of the entire lens may be 18 mm or more, for example, in the range of 19 mm to 23 mm, and the average of the central thicknesses may be in the range of 2 mm to 3 mm. The sum of the central spacings between the lenses on the optical axis (OA) may be 9 mm or more, for example, in the range of 9 mm to 13 mm, and may be less than the sum of the central thicknesses of the lenses. Additionally, the average value of the effective diameter of each lens surface (S1-S16) of the lens unit can be provided in the range of 8 mm or more, for example, 9 mm to 10 mm.

[0127]

[0128] In the optical system according to the first to third embodiments of the invention, the F number may be 2 or less, for example, in the range of 1.5 to 1.7. The vehicle optical system may have a horizontal field of view (FOV_H) in the Y-axis direction that may be greater than 110 degrees and less than 150 degrees, for example, in the range of 110 degrees to 130 degrees. In addition, the vertical field of view may be provided at an angle smaller than the horizontal field of view. The vertical field of view (FOV_V) may be greater than 50 degrees and less than 60 degrees, for example, in the range of 110 degrees to 130 degrees. The sensor length in the horizontal direction (Y) may be 8.064 mm±0.5 mm, and the sensor height in the vertical direction (X) may be 4.536 mm±0.5 mm. The horizontal field of view (FOV_H) is the field of view based on the horizontal length of the image sensor, and the vertical field of view (FOV_V) is the field of view based on the vertical length of the image sensor. Accordingly, changes in the focus position due to temperature changes can be suppressed, and various aberrations can be well-corrected for use as a vehicle camera.

[0129] Because the optical systems used in vehicle cameras typically monitor road conditions, they can be designed based on the horizontal field of view, rather than the entire field of view. The optical system according to this embodiment is designed with a certain margin based on the inscribed circle of the image sensor. This ensures guaranteed optical performance within the range that satisfies the horizontal field of view (FOV_H).

[0130]

[0131] Since the embodiment is an optical system applied to a vehicle camera, the first lens (101, 201, 301) may be provided as a glass material, even though it is designed to use both a plastic lens and a glass lens. This is because glass has the advantage of being scratch-resistant and insensitive to external temperature compared to plastic. The first lens (101, 201, 301) may have a spherical surface and be made of glass.

[0132] The second lens (102, 202, 302) positioned closest to the object side of the plastic lens may be a glass mold lens having an aspherical surface and made of glass. The glass mold lens may be manufactured by placing an optical glass ingot inside a mold that will have an aspherical shape and then heating and compressing it. The second lens (102, 202, 302) is made of a glass mold lens and can compensate for optical performance according to temperature changes.

[0133] In order to more effectively prevent scratches caused by foreign substances or objects placed inside a vehicle, a glass lens may be used as the first lens (101, 201, 301), and the object-side surface of the first lens (101, 201, 301) may have a gently curved shape so as not to come into contact with external structures. This minimizes the occurrence of scratches due to contact with external structures. For driver monitoring, front / rear photography of the vehicle, lane detection, and detection of debris around the vehicle while the vehicle is being driven, the angle of view may be greater than 110 degrees and less than 150 degrees, and may be, for example, in the range of 110 degrees to 130 degrees. This horizontal angle of view may be a preset angle for an advanced driver assistance system (ADAS).

[0134] The optical system (1000, 1100, 1200) 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 light incident on the optical system (1000, 1100, 1200) toward the lenses. Hereinafter, the optical system according to the embodiment will be described in detail.

[0135]

[0136] Below, the configuration of an optical system according to a first embodiment of the present invention is described with reference to the drawings.

[0137] FIG. 1 is a side cross-sectional view of an optical system according to the first embodiment and a camera module having the same, FIG. 2 is a table showing the values ​​of aspherical coefficients and conic constants (k) of each lens surface in the optical system according to the first embodiment, FIG. 3 is a table showing the thicknesses of each lens and the spacing between adjacent lenses in the optical system according to the first embodiment, FIG. 4 is a table showing Sag values ​​of each lens surface in the optical system according to the first embodiment, FIG. 5 is a table showing Slope Angle values ​​of each lens surface in the optical system according to the first embodiment, FIG. 6 is a graph showing data on diffraction MTF (Modulation Transfer Function) at room temperature of the optical system according to the first embodiment, FIG. 7 is a graph showing data on aberration characteristics at room temperature of the optical system according to the first embodiment, FIG. 8 is a graph showing data on diffraction MTF at low temperature of the optical system according to the first embodiment, and FIG. 9 is a graph showing data on diffraction MTF at low temperature of the optical system according to the first embodiment. This is a graph showing data on aberration characteristics at low temperatures of an optical system according to the first embodiment, FIG. 10 is a graph showing data on diffraction MTF at high temperatures of an optical system according to the first embodiment, and FIG. 11 is a graph showing data on aberration characteristics at high temperatures of an optical system according to the first embodiment.

[0138]

[0139] An optical system according to the first embodiment includes a lens unit, and the lens unit may include a first lens (101) to an eighth lens (108). The first to eighth lenses (101, 102, 103, 104, 105, 106, 107, 108) may be sequentially arranged along an optical axis (OA). Light corresponding to information about an object may pass through the first lens (101) to the eighth lens (108) and a filter (500) and be incident on an image sensor (400).

[0140] The lens section may be arranged in order from the object side to the image side, including a first lens (101), a second lens (102), a third lens (103), a fourth lens (104), a fifth lens (105), an aperture (STOP), a sixth lens (106), a seventh lens (107), and an eighth lens (108).

[0141] In another embodiment, one or more of another lens, a flat plate, and an optical member may be added between the first lens (101) to the eighth lens (108). In addition, one or more of another lens, a flat plate, and an optical member may be added in front of the first lens (101) or behind the eighth lens (108). In addition, one or more of another lens, a flat plate, and an optical member may be added between the aperture (STOP) and the lens, between the lens and the filter (500), and between the filter (500) and the image sensor (400). In this case, the filter (500) may be a flat plate lens. The refractive power of the flat plate lens may be '0'. The refractive power of the flat plate lens may be absent. In addition, a filter layer may be arranged between the aperture (STOP) and the lens, between the lens and the filter (500), and between the filter (500) and the image sensor (400). In this case, the filter layer may be coated to become a filter.

[0142] The first lens (101) may be arranged closest to the object side. The first lens (101) may be arranged farthest from the sensor side. The first lens (101) may have negative (-) refractive power on the optical axis (OA). The first lens (101) may include a plastic material or a glass material, and may be made of glass, for example. The first lens (101) made of glass can reduce changes in the center position and radius of curvature due to temperature changes in the surrounding environment, and can protect the incident side of the optical system (1000).

[0143] The first surface (S1) on the object side of the first lens (101) with respect to the optical axis may be convex, and the second surface (S2) on the sensor side may be concave. The first lens (101) may have a meniscus shape that is convex toward the object side. The first lens (101) may be made of glass and may have a spherical surface. At least one or both of the first surface (S1) and the second surface (S2) may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0144] Due to the refractive characteristics of the first lens (101), the second lens (102) can be further separated from the first lens (101). That is, the center spacing between the first and second lenses (101, 102) can be the largest within the lens unit.

[0145] The refractive index (n1) of the first lens (101) can satisfy the condition of n1>1.6 or n1>1.61. The radius of curvature of the first and second lenses (101, 102) can be increased, and lens manufacturing can be facilitated. If the refractive index (n1) of the first lens (101) is smaller than the condition, the lens surface must be formed to be sharply concave or convex in order to increase the refractive power of the first and second lenses (101, 102). In this case, lens manufacturing is not easy, the lens defect rate increases, and it may cause a decrease in yield.

[0146]

[0147] The second lens (102) may be arranged second from the object side. The second lens (102) may be arranged seventh from the sensor side. The second lens (102) may be arranged between the first lens (101) and the third lens (103). The second lens (102) may have positive (+) refractive power in the optical axis (OA). The second lens (102) may include a plastic or glass material. For example, the second lens (102) may be provided as a glass mold material.

[0148] The object-side third surface (S3) of the second lens (102) may be convex with respect to the optical axis (OA), and the sensor-side fourth surface (S4) may be concave. The second lens (102) may have a meniscus shape that is convex toward the object side. The second lens (102) may be made of a glass mold material and may be aspherical. At least one or both of the third surface (S3) and the fourth surface (S4) may be aspherical. The aspherical coefficients of the third and fourth surfaces (S3, S4) may be provided as S1 and S2 of L2 in FIG. 2. 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.

[0149]

[0150] The third lens (103) may be arranged third from the object side. The third lens (103) may be arranged sixth from the sensor side. The third lens (103) may be arranged between the second lens (102) and the fourth lens (104). The third lens (103) may have negative (-) refractive power on the optical axis (OA). The third lens (103) may include a plastic or glass material. For example, the third lens (103) may be provided as a plastic material.

[0151] The fifth surface (S5) on the object side of the third lens (103) with respect to the optical axis may be convex, and the sixth surface (S6) on the sensor side may be concave. The third lens (103) may have a meniscus shape that is convex toward the object side. The third lens (103) may be made of a plastic material and may be aspherical. At least one or both of the fifth surface (S5) and the sixth surface (S6) may be aspherical. The aspherical coefficients of the fifth and sixth surfaces (S5, S6) may be provided as S5 and S6 of L3 in FIG. 2.

[0152] The fifth surface (S5) of the third lens (103) may include a critical point from the optical axis (OA) to the end of the effective area. When the fifth surface (S5) has a critical point, it may be located in a range of 90% to 95%, preferably 91% to 95%, of the effective radius (r31) from the optical axis (OA). The critical point of the fifth surface (S5) may be located in a range of 4.5 mm to 4.9 mm, preferably 4.7 mm to 4.8 mm from the optical axis (OA). The sixth surface (S6) of the third lens (103) may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0153]

[0154] The fourth lens (104) may be arranged fourth from the object side. The fourth lens (104) may be arranged fifth from the sensor side. The fourth lens (104) may be arranged between the third lens (103) and the fifth lens (105). The fourth lens (104) may have positive (+) or negative (-) refractive power on the optical axis (OA). The fourth lens (104) may have negative (-) refractive power. The fourth lens (104) may include a plastic or glass material. For example, the fourth lens (104) may be provided as a plastic material.

[0155] The seventh surface (S7) on the object side of the fourth lens (104) with respect to the optical axis may be convex, and the eighth surface (S8) on the sensor side may be concave. The fourth lens (104) may have a meniscus shape that is convex toward the object side. The fourth lens (104) may have a meniscus shape that is concave toward the sensor side. The fourth lens (104) may be made of a plastic material and may be aspherical. At least one or both of the seventh surface (S7) and the eighth surface (S8) may be aspherical. Aspheric coefficients of the seventh and eighth surfaces (S7, S8) may be provided as S1 and S2 of L4 in FIG. 2. At least one or both of the seventh surface (S7) and the eighth surface (S8) may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0156]

[0157] The fifth lens (105) may be arranged as the fifth lens from the object side. The fifth lens (105) may be arranged as the fourth lens from the sensor side. The fifth lens (105) may be arranged between the fourth lens (104) and the sixth lens (106). The fifth lens (105) may have positive (+) or negative (-) refractive power on the optical axis (OA). The fifth lens (105) may have positive (+) refractive power. The fifth lens (105) may include a plastic or glass material. For example, the fifth lens (105) may be provided as a glass material.

[0158] With respect to the optical axis (OA), the ninth surface (S9) on the object side of the fifth lens (105) may be convex, and the tenth surface (S10) on the sensor side may be convex. The fifth lens (105) may have a shape in which both sides are convex. The fifth lens (105) may be made of glass 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) may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0159] The aperture (Stop) may be arranged around the sensor-side tenth surface (S10) of the fifth lens (105). The aperture (Stop) may be arranged around the object-side eleventh surface (S11) of the sixth lens (106). The aperture can reduce the TTL within the field of view range, and the optical system can be miniaturized. Accordingly, a decrease in the yield by weight of the optical system can be prevented, and production efficiency can be improved. In addition, the optical system can be miniaturized by reducing the TTL within the horizontal field of view (FOV_H) of 100 to 130 degrees.

[0160]

[0161] The sixth lens (106) may be arranged as the sixth lens from the object side. The sixth lens (106) may be arranged as the third lens from the sensor side. The sixth lens (106) may be arranged between the fifth lens (105) and the seventh lens (107). The sixth lens (106) may have positive (+) or negative (-) refractive power on the optical axis (OA). The sixth lens (106) may have positive (+) refractive power. The sixth lens (106) may include a plastic or glass material. For example, the sixth lens (106) may be provided as a plastic material.

[0162] With respect to the optical axis (OA), the object-side eleventh surface (S11) of the sixth lens (106) may be convex, and the sensor-side twelfth surface (S12) may be convex. The sixth lens (106) may have a convex shape on both sides. The sixth lens (106) may be made of a plastic material and may be aspherical. At least one or both of the eleventh surface (S11) and the twelfth surface (S12) may be aspherical. The aspherical coefficients of the eleventh and twelfth surfaces (S11, S12) may be provided as S1 and S2 of L6 in FIG. 2. At least one or both of the eleventh surface (S11) and the twelfth surface (S12) may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0163]

[0164] The seventh lens (107) may be arranged as the seventh lens from the object side. The seventh lens (107) may be arranged as the second lens from the sensor side. The seventh lens (107) may be arranged between the sixth lens (106) and the eighth lens (108). The seventh lens (107) may have positive (+) or negative (-) refractive power on the optical axis (OA). The seventh lens (107) may have negative (-) refractive power. The seventh lens (107) may include a plastic or glass material. For example, the seventh lens (107) may be provided as a plastic material.

[0165] With respect to the optical axis (OA), the 13th surface (S13) on the object side of the seventh lens (107) may be convex, and the 14th surface (S14) on the sensor side may be concave. The 7th lens (107) may have a meniscus shape that is convex toward the object side. The 7th lens (107) may have a meniscus shape that is concave toward the sensor side. The 7th lens (107) may be made of a plastic material and may be aspherical. At least one or both of the 13th surface (S13) and the 14th surface (S14) may be aspherical. The aspherical coefficients of the 13th and 14th surfaces (S13, S14) may be provided as S13 and S14 of L7 in FIG. 2.

[0166] The thirteenth surface (S13) of the seventh lens (107) may include a critical point from the optical axis (OA) to the end of the effective area. When the thirteenth surface (S13) has a critical point, it may be located in a range of 35% to 45%, preferably 38% to 43%, of the effective radius (r71) from the optical axis (OA). The critical point of the fifth surface (S5) may be located in a range of 1.3 mm to 1.7 mm, preferably 1.5 mm to 1.6 mm from the optical axis (OA). The fourteenth surface (S14) of the seventh lens (107) may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0167]

[0168] The eighth lens (108) may be positioned furthest from the object side. The eighth lens (108) may be positioned closest to the image sensor (500). The eighth lens (108) may have positive (+) or negative (-) refractive power on the optical axis (OA). The eighth lens (108) may have positive (+) refractive power. The eighth lens (108) may include a plastic or glass material. For example, the eighth lens (108) may be provided as a plastic material.

[0169] With respect to the optical axis (OA), the 15th surface (S15) on the object side of the 8th lens (108) may be convex, and the 16th surface (S16) on the sensor side may be convex. The 8th lens (108) may have a convex shape on both sides. At least one or both of the 15th surface (S15) and the 16th surface (S16) may be aspherical. The aspherical coefficients of the 15th and 16th surfaces (S15, S16) may be provided as S15 and S16 of L8 in FIG. 2.

[0170] The fifteenth surface (S15) may be provided without a critical point from the optical axis (OA) to the end of the effective area. The sixteenth surface (S16) of the eighth lens (108) may include a critical point from the optical axis (OA) to the end of the effective area. When the sixteenth surface (S16) has a critical point, it may be located in a range of 45% to 55%, preferably in a range of 50% to 52.5%, of the effective radius (r82) from the optical axis (OA). The critical point of the fifth surface (S5) may be located in a range of 1.8 mm to 2.3 mm, preferably in a range of 2 mm to 2.1 mm from the optical axis (OA).

[0171] The eighth lens (108) may be a plastic lens closest to the image sensor (500). In addition, by arranging two or more plastic lenses adjacent to the image sensor (500), aberrations such as spherical aberration and chromatic aberration can be improved by the lens surface having an aspherical surface, and the influence on the resolution can be controlled. In addition, by arranging the plastic lens as the lens adjacent to the image sensor (500), it can be insensitive to assembly tolerances compared to a glass lens. In other words, being insensitive to assembly tolerances means that even if the assembly is slightly different from the design during assembly, the optical performance may not be significantly affected. In addition, by providing the two lenses (107, 108) adjacent to the image sensor (500) as plastic, the optical performance can be improved by the lens surface having an aspherical surface, and for example, aberration characteristics can be improved and resolution deterioration can be prevented.

[0172] LensSurfaceRadiusThicknessndvdSemiApertureFocal length1S122.1962.0001.620363.394910.557-21.5817S28.0633.2206.8352S31 3.4111.9281.829724.03946.33842.2176S420.3150.5745.7313S55.2501.8001. 538855.97985.233-9.8018S62.3173.0583.6784S740.6952.9851.663321.24143 .627-60.4140S819.6000.5003.3385S913.7073.0191.620363.39493.3009.9067S 10-10.2010.5003.335STOP-1.9863.1436S116.9843.3681.538855.97984.0008. 0117S12-9.3920.5004.0427S13142.7591.6991.663321.24143.879-9.2106S145. 8310.6333.9128S157.1522.9861.538855.97984.09716.3992S1632.0391.8454.149FilterS17Infinity0.5004.197S18Infinity1.0004.205ImageInfinity0.000

[0173]

[0174] Table 1 shows the surface number (Surface), radius of curvature (Radius), center thickness of each lens or distance between lens surfaces (Thickness), refractive index (Index,nd), Abbe number (Abbe,vd), effective radius (Semi Aperture), and focal length (Fcoal length) of the lens according to the first embodiment of the present invention. At this time, the unit of the radius of curvature and thickness or distance may be mm.

[0175]

[0176] First embodiment First embodiment TTL34.1000ET13.1140F5.1000ET21.5084F_LG1-5.794ET33.4607F_LG25.962ET43.1236Fno1.6000ET52.0547FOV_H120.0000ET61.4584EPD3.1875ET73.0340BFL1.0000ET81.8105TD(L1S1~L8S2)33.1000ImgH4.0320SD(Stop~L8S2)13.5176

[0177]

[0178] Table 2 shows the characteristics of the optical system according to the first embodiment of the present invention.

[0179] TTL means the optical axis distance from the object-side vertex of the first lens (101) to the image surface, SD means the optical axis distance from the aperture (STOP) to the image-side surface of the eighth lens (108), TD means the optical axis distance from the object-side vertex of the first lens (101) to the image-side surface of the eighth lens (108), F means the total focal length, F_LG1 means the composite focal length of the first lens (101) to the fifth lens (105) in the object-side direction of the aperture (STOP), F_LG2 means the composite focal length of the sixth lens (106) to the eighth lens (108) in the image-side direction of the aperture (STOP), Fno means the ratio of the focal length of the lens to the effective diameter, ImgH means the distance from the optical axis (OA) to the diagonal end of the image sensor (400) or 1 / 2 of the maximum diagonal length, and FOV_H means It refers to the horizontal angle of view of the optical system, EPD refers to the diameter of the entrance pupil (effective aperture), BFL refers to the optical axis distance from the image side surface to the image surface of the eighth lens (108), and ET1 to ET8 refer to the thickness of the edge area of ​​each lens.

[0180]

[0181] The center thicknesses of the first to eighth lenses (101 to 108) are represented by CT1 to CT8, the edge thicknesses at the ends of the effective areas of each lens are represented by ET1 to ET8, the center gap between two adjacent lenses is represented by CG1 to CG7, and the edge gaps between the edges of each lens are represented by EG1 to EG7. The BFL (Back focal length) is the optical axis distance from the image sensor (500) to the center of the last lens. The TTL is the optical axis distance from the center of the first surface (S1) of the first lens (101) to the upper surface of the image sensor (500).

[0182] As shown in Fig. 2, among the lenses of the lens unit in the first embodiment, the lens surfaces of the second, third, fourth, sixth, seventh, and eighth lenses (102, 102, 104, 106, 107, and 108) may include aspherical surfaces having a 30th-order aspherical surface coefficient. For example, the second, third, fourth, sixth, seventh, and eighth lenses (102, 102, 104, 106, 107, and 108) may include lens surfaces having a 30th-order aspherical surface coefficient. As described above, since the aspherical surface having a 30th-order aspherical surface coefficient (a value other than "0") can significantly change the aspherical shape of the periphery, the optical performance of the periphery of the field of view (FOV) can be well corrected.

[0183] The thickness (T1-T8) of the first to eighth lenses (101-108) and the spacing (G1-G7) between adjacent two lenses can be set. As shown in Fig. 3, the thickness (T1-T8) of each lens in the Y-axis direction can be expressed at intervals of 0.1 mm or 0.2 mm or more, and the spacing (G1-G7) between each lens can be expressed at intervals of 0.1 mm or 0.2 mm or more.

[0184] When comparing the absolute values ​​of the curvature radii of each lens, the curvature radii of the thirteenth surface (S13) of the seventh lens (107) on the optical axis (OA) may be the largest among the lenses, and the curvature radii of the sixth surface (S6) of the third lens (103) may be the smallest among the lenses. The difference between the maximum curvature radii and the minimum curvature radii may be 60 times or more, for example, in the range of 70 to 80 times.

[0185] Since the effective diameter of a plastic lens is smaller than that of a glass lens, the lens placed on the object side of the plastic lens can have a strong refractive power to refract light through the plastic lens. In addition, the radius of curvature of the lens surface can be small to increase the refractive power.

[0186] The absolute value of the curvature radius of the first surface (S1) of the first lens (101) may be greater than the absolute value of the curvature radius of the second surface (S2). The absolute value of the curvature radius of the third surface (S3) of the second lens (102) may be less than the absolute value of the curvature radius of the fourth surface (S4). The absolute value of the curvature radius of the fifth surface (S5) of the third lens (103) may be greater than the absolute value of the curvature radius of the sixth surface (S6). The absolute value of the curvature radius of the seventh surface (S7) of the fourth lens (104) may be greater than the absolute value of the curvature radius of the eighth surface (S8). The absolute value of the curvature radius of the ninth surface (S9) of the fifth lens (105) may be greater than the absolute value of the curvature radius of the tenth surface (S10). The absolute value of the curvature radius of the eleventh surface (S11) of the sixth lens (106) may be smaller than the absolute value of the curvature radius of the twelfth surface (S12). The absolute value of the curvature radius of the thirteenth surface (S13) of the seventh lens (107) may be larger than the absolute value of the curvature radius of the fourteenth surface (S14). The absolute value of the curvature radius of the fifteenth surface (S15) of the eighth lens (108) may be smaller than the absolute value of the curvature radius of the sixteenth surface (S16).

[0187] The ratio of the radius of curvature of each lens can satisfy the following conditions.

[0188]

[0189] Condition 1: 2 < |L1R1 / L1R2| < 3

[0190] Condition 2: 0.5 < |L2R1 / L2R2| < 0.8

[0191] Condition 3: 2 < |L3R1 / L3R2| < 3

[0192] Condition 4: 2 < L4R1 / L4R2 < 3

[0193] Condition 5: 1 < |L5R1 / L5R2| < 2

[0194] Condition 6: 0.5 < |L6R1 / L6R2| < 1

[0195] Condition 7: 20 < |L7R1 / L7R2| < 25

[0196] Condition 8: 0.1 < L8R1 / L8R2 < 0.5

[0197]

[0198] When describing the central thickness (CT) of the lenses based on the optical axis, the central thickness (CT6) of the sixth lens (106) is the largest among the lenses, and the central thickness (CT7) of the seventh lens (107) is the smallest among the lenses. The difference between the maximum and minimum central thicknesses among the lenses may be in the range of 1.5 mm or more and 2.5 mm or less.

[0199] The central thickness of each lens may satisfy any one of the following conditions:

[0200] Condition 1: CT4, CT5, CT6, CT8 > CT1 > CT2, CT3, CT7

[0201] Condition 2: CT1, CT4, CT5, CT6, CT8 > CT2 > CT3, CT7

[0202] Condition 3: CT1, CT2, CT4, CT5, CT6, CT8 > CT3 > CT7

[0203] Condition 4: CT5, CT6, CT8 > CT4 > CT1, CT2, CT3, CT7

[0204] Condition 5: CT6 > CT5 > CT1, CT2, CT3, CT4, CT7, CT8

[0205] Condition 6: CT6 > CT1, CT2, CT3, CT4, CT5, CT7, CT8

[0206] Condition 7: CT1, CT2, CT3, CT4, CT5, CT6, CT8 > CT7

[0207] Condition 8: CT5, CT6 > CT8 > CT1, CT2, CT3, CT4, CT7

[0208]

[0209] In terms of 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 at least one of the center spacing (CG4) between the fourth and fifth lenses (104, 105) and the center spacing (CG6) between the sixth and seventh lenses (106, 107) may be minimum. The difference between the maximum center spacing and the minimum center spacing among the spaced lenses may be 2 mm or more, for example, in the range of 2.5 mm to 3.5 mm.

[0210] The center spacing between each lens can satisfy the conditions below.

[0211] Condition 1: CG1 > CG2, CG3, CG4, CG5, CG6, CG7

[0212] Condition 2: CG1, CG3, CG5, CG7 > CG2 > CG4, CG6

[0213] Condition 3: CG1 > CG3 > CG2, CG4, CG5, CG6, CG7

[0214] Condition 4: CG1, CG2, CG3, CG5, CG7 > CG4 = CG6

[0215] Condition 5: CG1, CG3 > CG5 > CG2, CG4, CG6, CG7

[0216] Condition 6: CG1, CG3, CG5 > CG7 > CG2, CG4, CG6

[0217]

[0218] Regarding the effective diameter, the lens having the maximum effective diameter may be a glass lens. The lens having the maximum effective diameter may be the first lens (101). Here, the effective diameter is the average of the effective diameters on the object side and the sensor side of each lens. The lens surface having the maximum effective diameter may be the first surface (S1) of the first lens (101).

[0219] The lens having the minimum effective diameter may be a lens arranged between the first lens (101) and the aperture (STOP). The lens having the minimum effective diameter may be the fifth lens (105). The lens surface having the minimum effective diameter may be the ninth surface (S9) of the fifth lens (105). The effective diameter of the plastic lens may be smaller than that of the glass lens. The plastic lens may be arranged adjacent to the image sensor.

[0220] The effective diameter of each lens can satisfy any one of the conditions below.

[0221] Condition 1: CA_L1 > CA_L2, CA_L3, CA_L4, CA_L5, CA_L6, CA_L7, CA_L8

[0222] Condition 2: CA_L1 > CA_L2 > CA_L3, CA_L4, CA_L5, CA_L6, CA_L7, CA_L8

[0223] Condition 3: CA_L1, CA_L2 > CA_L3 > CA_L4, CA_L5, CA_L6, CA_L7, CA_L8

[0224] Condition 4: CA_L1, CA_L2, CA_L3, CA_L6, CA_L7, CA_L8 > CA_L4 > CA_L5

[0225] Condition 5: CA_L1, CA_L2, CA_L3, CA_L4, CA_L6, CA_L7, CA_L8 > CA_L5

[0226] Condition 6: CA_L1, CA_L2, CA_L3, CA_L8 > CA_L6 > CA_L4, CA_L5, CA_L7

[0227] Condition 7: CA_L1, CA_L2, CA_L3, CA_L6, CA_L8 > CA_L7 > CA_L4, CA_L5

[0228] Condition 8: CA_L1, CA_L2, CA_L3 > CA_L8 > CA_L4, CA_L5, CA_L6, CA_L7

[0229]

[0230] In terms of refractive index, the refractive index of the second lens (102) may be the largest among the lenses and may be greater than 1.75, for example, greater than 1.8. Any one or all of the third lens (103), the sixth lens (106), and the eighth lens (108) may have the smallest refractive index among the lenses. For example, the refractive indices of the third lens (103), the sixth lens (106), and the eighth lens (108) may be the smallest among the lenses and may be less than 1.6, for example, less than 1.55. The difference between the maximum refractive index and the minimum refractive index may be 0.2 or more. By providing a lens close to an object as a high refractive index lens, and providing a lens adjacent to a glass lens and a lens adjacent to an image sensor (500) as a low refractive index lens made of a plastic material, the incidence efficiency can be increased, and the refractive power between the lenses made of glass and plastic can be adjusted to guide light to the image sensor (500).

[0231] The refractive index of each lens can satisfy any of the conditions below.

[0232] Condition 1: n1 = n5 > n2, n3, n4, n6, n7, n8

[0233] Condition 2: n2 > n1, n3, n4, n5, n6, n7, n8

[0234] Condition 3: n1, n2, n4, n5, n7 > n3 = n6 = n8

[0235] Condition 4: n2 > n4 = n7 > n1, n3, n5, n6, n8

[0236]

[0237] Comparing the Abbe numbers, the Abbe number of at least one of the first lens (101) and the fifth lens (105) is the largest among the lenses, and may be 60 or more. The Abbe number of at least one of the fourth lens (104) and the seventh lens (107) is the smallest among the lenses, and may be 25 or less. The difference between the maximum refractive index and the minimum Abbe number may be 40 or more. By providing the Abbe number of the fifth lens (105) arranged at the center of the optical system (1000) to be the largest, and the Abbe number of the seventh lens (107) having a low refractive index adjacent to the image sensor (500) to be the smallest, the chromatic dispersion of light traveling between the lenses made of glass and plastic can be controlled, and the chromatic dispersion between the lenses made of glass and plastic can be increased to guide the light to the image sensor (500).

[0238] The Abbe number of each lens can satisfy any of the conditions below.

[0239] Condition 1: v1 = v5 > v2, v3, v4, v6, v7, v8

[0240] Condition 2: v1, v3, v5, v6, v8 > v2 > v4, v7

[0241] Condition 3: v1, v5 > v3 = v6 = v8 > v2, v4, v7

[0242] Condition 4: v1, v2, v3, v5, v6, v8 > v4 = v7

[0243]

[0244] The focal lengths (F1, F3, F4, F7) of the first, third, fourth, and seventh lenses (101, 103, 104, and 107) may have negative (-) signs. The first, third, fourth, and seventh lenses (101, 103, 104, and 107) may have negative (-) refractive power. The focal lengths (F2, F5, F6, and F8) of the second, fifth, sixth, and eighth lenses (102, 105, 106, and 108) may have positive (+) signs. The second, fifth, sixth, and eighth lenses (102, 105, 106, and 108) may have positive (+) refractive power.

[0245] Additionally, the seventh lens (107) and the eighth lens (108), which are adjacently arranged lenses, can satisfy the following conditions.

[0246] Condition 1: Refractive index of lens with positive refractive power < refractive index of lens with negative refractive power

[0247] Condition 2: Dispersion of a lens with positive refractive power > Dispersion of a lens with negative refractive power

[0248] Here, among the plastic lenses, the eighth lens (108) has positive refractive power and the seventh lens (107) has negative refractive power, so that according to conditions 1 and 2, the refractive index of the eighth lens (108) is smaller than the refractive index of the seventh lens (107), and the dispersion value of the eighth lens (108) is larger than the dispersion value of the seventh lens (107). The chromatic aberration occurring in the plastic lens can be corrected by the plastic lens. In addition, since the seventh lens (107) and the eighth lens (108), which are plastic lenses arranged in succession, satisfy the conditions of a refractive index difference of 0.1 or more and 0.15 or less and an Abbe number difference of 20 or more and 50 or less, the chromatic aberration occurring in the plastic lens can be compensated for by the plastic lens.

[0249] Optical systems suffer from chromatic aberration, and chromatic aberration is corrected by using cemented lenses or two lenses arranged in series. As the temperature changes from low to high, the lenses repeatedly contract and expand. Since lenses made of the same material exhibit the same amount of change in lens characteristics due to temperature changes, it is effective to correct chromatic aberration between lenses made of the same material even when the temperature changes. Therefore, in the first embodiment of the present invention, chromatic aberration occurring in a plastic lens can be corrected by using the seventh lens (107) and the eighth lens (108).

[0250]

[0251] When comparing the focal lengths in absolute values, the focal length of the fourth lens (104) is the largest among the lenses, and may be 55 or more and 65 or less. 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 7 or more and 9 or less.

[0252] The absolute value of the focal length of each lens can satisfy any of the conditions below.

[0253] Condition 1: |f2|, |f4|> |f1| > |f3|, |f5|, |f6|, |f7|, |f8|

[0254] Condition 2: |f4| > |f2| > |f1|, |f3|, |f5|, |f6|, |f7|, |f8|

[0255] Condition 3: |f1|, |f2|, |f4|, |f5|, |f8| > |f3| > |f6|, |f7|

[0256] Condition 4: |f4| > |f1|, |f2|, |f3|, |f5|, |f6|, |f7|, |f8|

[0257] Condition 5: |f1|, |f2|, |f4|, |f8| > |f5| > |f3|, |f6|, |f7|

[0258] Condition 6: |f1|, |f2|, |f3|, |f4|, |f5|, |f7|, |f8| > |f6|

[0259] Condition 7: |f1|, |f2|, |f3|, |f4|, |f5|, |f8| > |f7| > |f6|

[0260] Condition 8: |f1|, |f2|, |f4| > |f8| > |f3|, |f5|, |f6|, |f7|

[0261]

[0262] The thickness (T1) of the first lens (101) may be a difference of 1.3 times or more between the maximum thickness and the minimum thickness, for example, in a range of 1.3 to 1.8 times, and the center thickness (CT1) may be a minimum and the edge thickness (ET1) may be a maximum. The thickness (T2) of the second lens (102) may be a maximum thickness in a range of 1 to 1.5 times the minimum thickness. The second lens (102) may be a maximum center thickness (CT2) and the edge thickness (ET2) may be a minimum. The thickness (T3) of the third lens (103) may be a minimum at the center and a maximum at the edge, and the maximum thickness is in a range of 1.5 to 2 times the minimum thickness. The thickness (T4) of the fourth lens (104) may be a minimum at the center and a maximum at the edge, and the maximum thickness is in a range of 1 to 1.5 times the minimum thickness. The thickness (T5) of the fifth lens (105) may be maximum at the center and minimum at the edge, and the maximum thickness is in the range of 1.3 to 1.5 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 2 to 2.5 times the minimum thickness. The thickness (T7) of the seventh lens (107) may be minimum at the center and maximum at the edge, and the maximum thickness is in the range of 1.5 to 2 times the minimum thickness. The thickness (T8) of the eighth lens (108) 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.

[0263] The ratio of the center thickness to the edge thickness of each lens can be referred to as the thickness ratio. When the ratio of the larger to smaller center thickness to the smaller edge thickness is between 2 and 2.5, lens manufacturing is easy and can be advantageous in terms of yield.

[0264] The thickness of each lens can satisfy any of the conditions below.

[0265] Condition 1: 0.5 < CT1 / ET1 < 1, 1.3 < ET1 / CT1 < 1.8

[0266] Condition 2: 1 < CT2 / ET2 < 1.5, 0.5 < ET2 / CT2 < 1

[0267] Condition 3: 0.3 < CT3 / ET3 < 0.7, 1.5 < ET3 / CT3 < 2

[0268] Condition 4: 0.5 < CT4 / ET4 < 1, 1 < ET4 / CT4 < 1.5

[0269] Condition 5: 1.3 < CT5 / ET5 < 1.5, 0.5 < ET5 / CT5 < 1

[0270] Condition 6: 2 < CT6 / ET6 < 2.5, 0.1 < ET6 / CT6 < 0.5

[0271] Condition 7: 0.3 < CT7 / ET7 < 0.7, 1.5 < ET7 / CT7 < 2

[0272] Condition 8: 1.5 < CT8 / ET8 < 2, 0.5 < ET8 / CT8 < 1

[0273] Condition 9: 1 < ΣCT / ΣET < 1.2, 0.5 < ΣET / ΣCT < 1

[0274]

[0275] Among the gaps (G1-G7) between the lenses, the first gap (G1) between the first and second lenses (101, 102) may have a maximum in the center and a minimum in the edge. The second gap (G2) between the second and third lenses (102, 103) may have a minimum in the center and a maximum in the edge. The third gap (G3) between the third and fourth lenses (103, 104) may have a minimum in the edge and a maximum in the center. The fourth gap (G4) between the fourth and fifth lenses (104, 105) may have a minimum in the center and a maximum in the edge. The fifth gap (G5) between the fifth and sixth lenses (105, 106) may have a minimum in the center and a maximum in the edge. The sixth gap (G6) between the sixth and seventh lenses (106, 107) may have a minimum in the center and a maximum in the edge. The seventh gap (G7) between the seventh and eighth lenses (107, 108) may be maximum at the center and minimum at the edge.

[0276]

[0277] FIGS. 6, 8, and 10 are graphs showing the diffraction MTF (Modulation Transfer Function) at room temperature, low temperature, and high temperature in the optical system of FIG. 1, and are graphs showing the modulation ratio according to spatial frequency. As shown in FIGS. 6, 8, and 10, in the first embodiment of the invention, the deviation of the MTF at low temperature or high temperature based on room temperature may be less than 10%, that is, 7% or less.

[0278] FIGS. 7, 9, and 11 are graphs showing aberration characteristics at room temperature, low temperature, and high temperature in the optical system of FIG. 1. In the aberration graphs of FIGS. 7, 9, and 11, spherical aberration (longitudinal spherical aberration), astigmatic field curves, and distortion are measured from left to right. In FIGS. 7, 9, and 11, the X-axis may represent a focal length (mm) and a degree of distortion (%), and the Y-axis may represent the height of the image. In addition, the graph for spherical aberration is a graph for light in wavelength bands of about 435 nm, about 486 nm, about 546 nm, about 587 nm, and about 656 nm, and the graphs for astigmatism and distortion are graphs for light in wavelength bands of about 546 nm. In the aberration diagrams of FIGS. 7, 9, and 11, the closer the curves at room temperature, low temperature, and high temperature are to the Y-axis, the better the aberration correction function can be interpreted. It can be seen that the optical system (1000) according to the first embodiment has measured values ​​close to the Y-axis in almost all areas. That is, the optical system (1000) according to the first embodiment has improved resolution and can have good optical performance not only in the center of the field of view (FOV) but also in the periphery. Here, the low temperature is -20 degrees or lower, for example, in the range of -20 to -40 degrees, the room temperature is in the range of 22 degrees ± 5 degrees or in the range of 18 degrees to 27 degrees, and the high temperature can be 85 degrees or higher, for example, in the range of 85 to 105 degrees. Accordingly, it can be seen that the decrease in the luminance ratio (modulation) from the low temperature to the high temperature of FIGS. 7, 9, and 11 is less than 10%, for example, 5% or lower, or is almost unchanged.

[0279] Table 3 compares changes in optical characteristics such as EFL, BFL, F number (F#), TTL, and field of view (FOV_H) at room temperature, low temperature, and high temperature in the optical system according to the first embodiment, and it can be seen that the change rate of optical characteristics at low temperature is 5% or less, for example, 3% or less, based on room temperature, and it can be seen that the change rate of optical characteristics at low temperature is 5% or less, for example, 3% or less, based on room temperature.

[0280]

[0281] Room temperature low temperature high temperature low temperature / Room temperature high temperature / Room temperature EFL(F) 5.105.055.1799.01%102.37% BFL 3.353.343.3599.70%100.29% F# 1.601.591.6199.37%101.25% TTL 34.1034.0334.1999.79%100.47% FOV_H 120.00122.35117.22101.95%95.80%

[0282]

[0283] Therefore, as shown in Table 3, it can be seen that the change in optical characteristics according to the temperature change from low temperature to high temperature, for example, the change rate of effective focal length (EFL), TTL, BFL, F number, and field of view (FOV_H) is 10% or less, that is, 5% or less, for example, in the range of 0 to 5%. This means that even if at least one or two or more plastic lenses are used, the design can enable temperature compensation for the plastic lenses, thereby preventing a decrease in the reliability of the optical characteristics.

[0284] 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.

[0285]

[0286] Below, the configuration of an optical system according to a second embodiment of the present invention is described with reference to the drawings.

[0287] FIG. 12 is a side cross-sectional view of an optical system according to the second embodiment and a camera module having the same, FIG. 13 is a table showing the aspherical coefficient value and the conic constant (k) of each lens surface in the optical system according to the second embodiment, FIG. 14 is a table showing the thickness of each lens and the spacing between adjacent lenses in the optical system according to the second embodiment, FIG. 15 is a table showing the Sag values ​​of each lens surface in the optical system according to the second embodiment, FIG. 16 is a table showing the Slope Angle values ​​of each lens surface in the optical system according to the second embodiment, FIG. 17 is a graph showing data on the diffraction MTF (Modulation Transfer Function) at room temperature of the optical system according to the second embodiment, FIG. 18 is a graph showing data on the aberration characteristics of the optical system according to the second embodiment at room temperature, and FIG. 19 is a graph showing data on the diffraction MTF at low temperature of the optical system according to the second embodiment. FIG. 20 is a graph showing data on aberration characteristics at low temperatures of an optical system according to the second embodiment of the present invention, FIG. 21 is a graph showing data on diffraction MTF at high temperatures of an optical system according to the second embodiment of the present invention, and FIG. 22 is a graph showing data on aberration characteristics at high temperatures of an optical system according to the second embodiment of the present invention.

[0288] An optical system according to a second embodiment includes a lens unit, and the lens unit may include a first lens (201) to an eighth lens (208). The first to eighth lenses (201, 202, 203, 204, 205, 206, 207, 208) may be sequentially arranged along an optical axis (OA). Light corresponding to information about an object may pass through the first lens (201) to the eighth lens (208) and a filter (500) and be incident on an image sensor (400).

[0289] The lens section may be arranged in order from the object side to the image side, including a first lens (201), a second lens (202), a third lens (203), a fourth lens (204), a fifth lens (205), an aperture (STOP), a sixth lens (206), a seventh lens (207), and an eighth lens (208).

[0290] In another embodiment, one or more of another lens, a flat plate, and an optical member may be added between the first lens (201) to the eighth lens (208). In addition, one or more of another lens, a flat plate, and an optical member may be added in front of the first lens (201) or behind the eighth lens (208). In addition, one or more of another lens, a flat plate, and an optical member may be added between the aperture (STOP) and the lens, between the lens and the filter (500), and between the filter (500) and the image sensor (400). In this case, the filter (500) may be a flat plate lens. The refractive power of the flat plate lens may be '0'. The refractive power of the flat plate lens may be zero. In addition, a filter layer may be arranged between the aperture (STOP) and the lens, between the lens and the filter (500), and between the filter (500) and the image sensor (400). In this case, the filter layer may be coated to become a filter.

[0291] The first lens (201) may be arranged closest to the object side. The first lens (201) may be arranged farthest from the sensor side. The first lens (201) may have negative (-) refractive power on the optical axis (OA). The first lens (201) may include a plastic material or a glass material, and may be made of glass, for example. The first lens (201) made of glass can reduce changes in the center position and radius of curvature due to temperature changes in the surrounding environment, and can protect the incident side of the optical system (1000).

[0292] The first surface (S1) on the object side of the first lens (201) with respect to the optical axis 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 be made of glass and may have a spherical surface. At least one or both of the first surface (S1) and the second surface (S2) may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0293] The refractive index (n1) of the first lens (201) can satisfy the condition of n1>1.6 or n1>1.61. The radius of curvature of the first and second lenses (201, 202) can be increased, and lens manufacturing can be facilitated. If the refractive index (n1) of the first lens (201) is smaller than the condition, the lens surface must be formed to be sharply concave or convex in order to increase the refractive power of the first and second lenses (201, 202). In this case, lens manufacturing is not easy, the lens defect rate increases, and it may cause a decrease in yield.

[0294]

[0295] The second lens (202) may be arranged second from the object side. The second lens (202) may be arranged seventh from the sensor side. The second lens (202) may be arranged between the first lens (201) and the third lens (203). The second lens (202) may have positive refractive power in the optical axis (OA). The second lens (202) may include a plastic or glass material. For example, the second lens (202) may be provided as a glass mold material.

[0296] The object-side third surface (S3) of the second lens (202) with respect to the optical axis (OA) may be convex, and the sensor-side fourth surface (S4) may be convex. The second lens (202) may have a convex shape on both sides. The second lens (202) may be made of a glass mold material and may be aspherical. At least one or both of the third surface (S3) and the fourth surface (S4) may be aspherical. The aspherical coefficients of the third and fourth surfaces (S3, S4) may be provided as S1 and S2 of L2 in FIG. 13. 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.

[0297]

[0298] The third lens (203) may be arranged third from the object side. The third lens (203) may be arranged sixth from the sensor side. The third lens (203) may be arranged between the second lens (202) and the fourth lens (204). The third lens (203) may have negative (-) refractive power on the optical axis (OA). The third lens (203) may include a plastic or glass material. For example, the third lens (203) may be provided as a plastic material.

[0299] The fifth surface (S5) on the object side of the third lens (203) with respect to the optical axis may be convex, and the sixth surface (S6) on the sensor side may be concave. The third lens (203) may have a meniscus shape that is convex toward the object side. The third lens (203) may be made of a plastic material and may be aspherical. At least one or both of the fifth surface (S5) and the sixth surface (S6) may be aspherical. The aspherical coefficients of the fifth and sixth surfaces (S5, S6) may be provided as S5 and S6 of L3 in FIG. 13.

[0300] The fifth surface (S5) of the third lens (203) may include a critical point from the optical axis (OA) to the end of the effective area. When the fifth surface (S5) has a critical point, it may be located in a range of 75% to 85%, preferably in a range of 80% to 83%, of the effective radius (r31) from the optical axis (OA). The critical point of the fifth surface (S5) may be located in a range of 3.5 mm to 4 mm, preferably in a range of 3.7 mm to 3.8 mm from the optical axis (OA). The sixth surface (S6) of the third lens (203) may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0301]

[0302] The fourth lens (204) may be arranged fourth from the object side. The fourth lens (204) may be arranged fifth from the sensor side. The fourth lens (204) may be arranged between the third lens (203) and the fifth lens (205). The fourth lens (204) may have positive (+) or negative (-) refractive power on the optical axis (OA). The fourth lens (204) may have negative (-) refractive power. The fourth lens (204) may include a plastic or glass material. For example, the fourth lens (204) may be provided as a plastic material.

[0303] The seventh surface (S7) on the object side of the fourth lens (204) with respect to the optical axis may be convex, and the eighth surface (S8) on the sensor side may be concave. The fourth lens (204) may have a meniscus shape that is convex toward the object side. The fourth lens (204) may have a meniscus shape that is concave toward the sensor side. The fourth lens (204) may be made of a plastic material and may be aspherical. At least one or both of the seventh surface (S7) and the eighth surface (S8) may be aspherical. Aspheric coefficients of the seventh and eighth surfaces (S7, S8) may be provided as S1 and S2 of L4 in FIG. 13. At least one or both of the seventh surface (S7) and the eighth surface (S8) may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0304]

[0305] The fifth lens (205) may be arranged as the fifth lens from the object side. The fifth lens (205) may be arranged as the fourth lens from the sensor side. The fifth lens (205) may be arranged between the fourth lens (204) and the sixth lens (206). The fifth lens (205) may have positive (+) or negative (-) refractive power on the optical axis (OA). The fifth lens (205) may have positive (+) refractive power. The fifth lens (205) may include a plastic or glass material. For example, the fifth lens (205) may be provided as a glass material.

[0306] With respect to the optical axis (OA), the ninth surface (S9) on the object side of the fifth lens (205) may be convex, and the tenth surface (S10) on the sensor side may be convex. The fifth lens (205) may have a shape in which both sides are convex. The fifth lens (205) may be made of glass 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) may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0307] The aperture (Stop) may be arranged around the sensor-side tenth surface (S10) of the fifth lens (205). The aperture (Stop) may be arranged around the object-side eleventh surface (S11) of the sixth lens (206). The aperture can reduce the TTL within the field of view range, and the optical system can be miniaturized. Accordingly, a decrease in the yield by weight of the optical system can be prevented, and production efficiency can be improved. In addition, the optical system can be miniaturized by reducing the TTL within the horizontal field of view (FOV_H) of 100 to 130 degrees.

[0308]

[0309] The sixth lens (206) may be arranged as the sixth lens from the object side. The sixth lens (206) may be arranged as the third lens from the sensor side. The sixth lens (206) may be arranged between the fifth lens (205) and the seventh lens (207). The sixth lens (206) may have positive (+) or negative (-) refractive power on the optical axis (OA). The sixth lens (206) may have positive (+) refractive power. The sixth lens (206) may include a plastic or glass material. For example, the sixth lens (206) may be provided as a plastic material.

[0310] With respect to the optical axis (OA), the object-side eleventh surface (S11) of the sixth lens (206) may be convex, and the sensor-side twelfth surface (S12) may be convex. The sixth lens (206) may have a convex shape on both sides. The sixth lens (206) may be made of a plastic material and may be aspherical. At least one or both of the eleventh surface (S11) and the twelfth surface (S12) may be aspherical. The aspherical coefficients of the eleventh and twelfth surfaces (S11, S12) may be provided as S1 and S2 of L6 in FIG. 13. At least one or both of the eleventh surface (S11) and the twelfth surface (S12) may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0311]

[0312] The seventh lens (207) may be arranged as the seventh lens from the object side. The seventh lens (207) may be arranged as the second lens from the sensor side. The seventh lens (207) may be arranged between the sixth lens (206) and the eighth lens (208). The seventh lens (207) may have positive (+) or negative (-) refractive power on the optical axis (OA). The seventh lens (207) may have negative (-) refractive power. The seventh lens (207) may include a plastic or glass material. For example, the seventh lens (207) may be provided as a plastic material.

[0313] With respect to the optical axis (OA), the 13th surface (S13) on the object side of the seventh lens (207) may be concave, and the 14th surface (S14) on the sensor side may be concave. The seventh lens (207) may have a shape in which both sides are concave. The seventh lens (207) may be made of a plastic material and may be aspherical. At least one or both of the 13th surface (S13) and the 14th surface (S14) may be aspherical. The aspherical coefficients of the 13th and 14th surfaces (S13, S14) may be provided as S13 and S14 of L7 in FIG. 13.

[0314]

[0315] The eighth lens (208) may be positioned furthest from the object side. The eighth lens (208) may be positioned closest to the image sensor (500). The eighth lens (208) may have positive (+) or negative (-) refractive power on the optical axis (OA). The eighth lens (208) may have positive (+) refractive power. The eighth lens (208) may include a plastic or glass material. For example, the eighth lens (208) may be provided as a plastic material.

[0316] With respect to the optical axis (OA), the 15th surface (S15) on the object side of the 8th lens (208) may be convex, and the 16th surface (S16) on the sensor side may be convex. The 8th lens (208) may have a convex shape on both sides. At least one or both of the 15th surface (S15) and the 16th surface (S16) may be aspherical. The aspherical coefficients of the 15th and 16th surfaces (S15, S16) may be provided as S15 and S16 of L8 in FIG. 13.

[0317] The eighth lens (208) may be a plastic lens closest to the image sensor (500). In addition, by arranging two or more plastic lenses adjacent to the image sensor (500), aberrations such as spherical aberration and chromatic aberration can be improved by the lens surface having an aspherical surface, and the influence on the resolution can be controlled. In addition, by arranging the plastic lens as the lens adjacent to the image sensor (500), it can be insensitive to assembly tolerances compared to a glass lens. In other words, being insensitive to assembly tolerances means that even if the assembly is slightly different from the design during assembly, the optical performance may not be significantly affected. In addition, by providing the two lenses (207, 208) adjacent to the image sensor (500) as plastic, the optical performance can be improved by the lens surface having an aspherical surface, and for example, aberration characteristics can be improved and resolution deterioration can be prevented.

[0318]

[0319] LensSurfaceRadiusThicknessndvdSemiApertureFocal length1S148.2612.0051.620363.394911.358-16.6809S28.3851.8367.1072S345 .4762.9821.829724.03946.78048.0473S4-313.4581.1285.0043S53.7371.8001. 538855.97984.598-10.7581S61.8892.2953.6884S737.8002.9851.663321.24143 .673-164.4380S827.1880.5003.3425S912.0133.8221.620363.39493.3009.5532 S10-10.2710.5003.399STOP-0.5013.2316S117.9162.9841.538855.97984.1008. 3761S12-9.1120.5003.7577S13-152.6481.5061.663321.24143.705-9.0261S146 .2562.1923.8598S157.1623.6891.538855.97984.65312.2851S16-71.5001.3754.766FilterS17Infinity0.5004.293S18Infinity1.0004.218ImageInfinity0.000

[0320]

[0321] Table 4 shows the surface number (Surface), radius of curvature (Radius), center thickness of each lens or distance between lens surfaces (Thickness), refractive index (Index,nd), Abbe number (Abbe,vd), effective radius (Semi Aperture), and focal length (Fcoal length) of the lens according to the second embodiment of the present invention. At this time, the unit of the radius of curvature and thickness or distance may be mm.

[0322]

[0323] Second embodiment Second embodiment TTL34.1000ET13.1140F5.1000ET21.5084F_LG1-5.666ET33.4607F_LG26.824ET43.1236Fno1.6000ET52.0547FOV_H120.0000ET61.4584EPD3.1875ET73.0340BFL1.0000ET81.8105TD(L1S1 ~L8S2)33.1000ImgH4.0320SD(Stop~L8S2)13.2473

[0324]

[0325] Table 5 shows the characteristics of the optical system according to the second embodiment of the present invention.

[0326] TTL means the optical axis distance from the object-side vertex of the first lens (201) to the image surface, SD means the optical axis distance from the aperture (STOP) to the image-side surface of the eighth lens (208), TD means the optical axis distance from the object-side vertex of the first lens (201) to the image-side surface of the eighth lens (208), F means the total focal length, F_LG1 means the composite focal length of the first lens (201) to the fourth lens (204) in the object-side direction of the aperture (STOP), F_LG2 means the composite focal length of the fifth lens (205) to the eighth lens (208) in the image-side direction of the aperture (STOP), Fno means the ratio of the focal length of the lens to the effective diameter, ImgH means the distance from the optical axis (OA) to the diagonal end of the image sensor (400) or 1 / 2 of the maximum diagonal length, and FOV_H means It refers to the horizontal angle of view of the optical system, EPD refers to the diameter of the entrance pupil (effective aperture), BFL refers to the optical axis distance from the image side surface to the image surface of the eighth lens (208), and ET1 to ET8 refer to the thickness of the edge area of ​​each lens.

[0327]

[0328] The center thicknesses of the first to eighth lenses (201 to 208) are represented by CT1 to CT8, the edge thicknesses at the ends of the effective areas of each lens are represented by ET1 to ET8, the center gap between two adjacent lenses is represented by CG1 to CG7, and the edge gaps between the edges of each lens are represented by EG1 to EG7. The BFL (Back focal length) is the optical axis distance from the image sensor (500) to the center of the last lens. The TTL is the optical axis distance from the center of the first surface (S1) of the first lens (201) to the upper surface of the image sensor (500).

[0329] As shown in Fig. 12, among the lenses of the lens unit in the second embodiment, the lens surfaces of the second, third, fourth, sixth, seventh, and eighth lenses (202, 202, 204, 206, 207, and 208) may include aspherical surfaces having a 30th-order aspherical surface coefficient. For example, the second, third, fourth, sixth, seventh, and eighth lenses (202, 202, 204, 206, 207, and 208) may include lens surfaces having a 30th-order aspherical surface coefficient. As described above, since the aspherical surface having a 30th-order aspherical surface coefficient (a non-zero value) can significantly change the aspherical shape of the periphery, the optical performance of the periphery of the field of view (FOV) can be well corrected.

[0330] The thickness (T1-T8) of the first to eighth lenses (201-208) and the spacing (G1-G7) between adjacent two lenses can be set. As shown in Fig. 14, the thickness (T1-T8) of each lens in the Y-axis direction can be expressed at intervals of 0.1 mm or 0.2 mm or more, and the spacing (G1-G7) between each lens can be expressed at intervals of 0.1 mm or 0.2 mm or more.

[0331] When comparing the absolute values ​​of the curvature radii of each lens, the curvature radii of the fourth surface (S4) of the second lens (202) on the optical axis (OA) may be the largest among the lenses, and the curvature radii of the sixth surface (S6) of the third lens (203) may be the smallest among the lenses. The difference between the maximum and minimum curvature radii may be 150 times or more, for example, in the range of 160 to 180 times.

[0332] Since the effective diameter of a plastic lens is smaller than that of a glass lens, the lens placed on the object side of the plastic lens can have a strong refractive power to refract light through the plastic lens. In addition, the radius of curvature of the lens surface can be small to increase the refractive power.

[0333] The absolute value of the curvature radius of the first surface (S1) of the first lens (201) may be greater than the absolute value of the curvature radius of the second surface (S2). The absolute value of the curvature radius of the third surface (S3) of the second lens (202) may be less than the absolute value of the curvature radius of the fourth surface (S4). The absolute value of the curvature radius of the fifth surface (S5) of the third lens (203) may be greater than the absolute value of the curvature radius of the sixth surface (S6). The absolute value of the curvature radius of the seventh surface (S7) of the fourth lens (204) may be greater than the absolute value of the curvature radius of the eighth surface (S8). The absolute value of the curvature radius of the ninth surface (S9) of the fifth lens (205) may be greater than the absolute value of the curvature radius of the tenth surface (S10). The absolute value of the curvature radius of the eleventh surface (S11) of the sixth lens (206) may be smaller than the absolute value of the curvature radius of the twelfth surface (S12). The absolute value of the curvature radius of the thirteenth surface (S13) of the seventh lens (207) may be larger than the absolute value of the curvature radius of the fourteenth surface (S14). The absolute value of the curvature radius of the fifteenth surface (S15) of the eighth lens (208) may be smaller than the absolute value of the curvature radius of the sixteenth surface (S16).

[0334] The ratio of the radius of curvature of each lens can satisfy the following conditions.

[0335]

[0336] Condition 1: 5 < |L1R1 / L1R2| < 6

[0337] Condition 2: 0.1 < |L2R1 / L2R2| < 0.5

[0338] Condition 3: 1 < |L3R1 / L3R2| < 2

[0339] Condition 4: 1 < L4R1 / L4R2 < 2

[0340] Condition 5: 1 < |L5R1 / L5R2| < 2

[0341] Condition 6: 0.5 < |L6R1 / L6R2| < 1

[0342] Condition 7: 20 < |L7R1 / L7R2| < 25

[0343] Condition 8: 0.1 < |L8R1 / L8R2| < 0.5

[0344]

[0345] When describing the central thickness (CT) of the lenses based on the optical axis, the central thickness (CT5) of the fifth lens (205) is the largest among the lenses, and the central thickness (CT7) of the seventh lens (207) is the smallest among the lenses. The difference between the maximum and minimum central thicknesses among the lenses may be in the range of 1.5 mm or more and 2.5 mm or less.

[0346] The central thickness of each lens may satisfy any one of the following conditions:

[0347] Condition 1: CT2, CT4, CT5, CT6, CT8 > CT1 > CT3, CT7

[0348] Condition 2: CT4, CT5, CT6, CT8 > CT2 > CT1, CT3, CT7

[0349] Condition 3: CT1, CT2, CT4, CT5, CT6, CT8 > CT3 > CT7

[0350] Condition 4: CT5, CT6, CT8 > CT4 > CT1, CT2, CT3, CT7

[0351] Condition 5: CT5 > CT1, CT2, CT3, CT4, CT6, CT7, CT8

[0352] Condition 6: CT5, CT8 > CT6 > CT1, CT2, CT3, CT4, CT7

[0353] Condition 7: CT1, CT2, CT3, CT4, CT5, CT6, CT8 > CT7

[0354] Condition 8: CT6 > CT8 > CT1, CT2, CT3, CT4, CT5, CT7

[0355]

[0356] Regarding the center spacing (CG) between the lenses, the center spacing (CG3) between the third lens (203) and the fourth lens (204) may be maximum, and at least one of the center spacing (CG4) between the fourth and fifth lenses (204, 205) and the center spacing (CG6) between the sixth and seventh lenses (206, 206) may be minimum. The difference between the maximum center spacing and the minimum center spacing among the spaced lens spacings may be 2 mm or more, for example, in the range of 2.5 mm to 3.5 mm.

[0357] The center spacing between each lens can satisfy the conditions below.

[0358] Condition 1: CG3, CG7 > CG1 > CG2, CG4, CG5, CG6

[0359] Condition 2: CG1, CG3, CG7 > CG2 > CG4, CG5, CG6

[0360] Condition 3: CG3 > CG1, CG2, CG4, CG5, CG6, CG7

[0361] Condition 4: CG1, CG2, CG3, CG5, CG7 > CG4 = CG6

[0362] Condition 5: CG1, CG2, CG3, CG7 > CG5 > CG4, CG6

[0363] Condition 6: CG3 > CG7 > CG1, CG2, CG4, CG5, CG6

[0364]

[0365] Regarding the effective diameter, the lens having the maximum effective diameter may be a glass lens. The lens having the maximum effective diameter may be the first lens (201). Here, the effective diameter is the average of the effective diameters on the object side and the sensor side of each lens. The lens surface having the maximum effective diameter may be the first surface (S1) of the first lens (201).

[0366] The lens having the minimum effective diameter may be a lens arranged between the first lens (201) and the aperture (STOP). The lens having the minimum effective diameter may be the fifth lens (205). The lens surface having the minimum effective diameter may be the ninth surface (S9) of the fifth lens (205). The effective diameter of the plastic lens may be smaller than that of the glass lens. The plastic lens may be arranged adjacent to the image sensor.

[0367] The effective diameter of each lens can satisfy any one of the conditions below.

[0368] Condition 1: CA_L1 > CA_L2, CA_L3, CA_L4, CA_L5, CA_L6, CA_L7, CA_L8

[0369] Condition 2: CA_L1 > CA_L2 > CA_L3, CA_L4, CA_L5, CA_L6, CA_L7, CA_L8

[0370] Condition 3: CA_L1, CA_L2, CA_L8 > CA_L3 > CA_L4, CA_L5, CA_L6, CA_L7

[0371] Condition 4: CA_L1, CA_L2, CA_L3, CA_L6, CA_L7, CA_L8 > CA_L4 > CA_L5

[0372] Condition 5: CA_L1, CA_L2, CA_L3, CA_L4, CA_L6, CA_L7, CA_L8 > CA_L5

[0373] Condition 6: CA_L1, CA_L2, CA_L3, CA_L8 > CA_L6 > CA_L4, CA_L5, CA_L7

[0374] Condition 7: CA_L1, CA_L2, CA_L3, CA_L6, CA_L8 > CA_L7 > CA_L4, CA_L5

[0375] Condition 8: CA_L1, CA_L2 > CA_L8 > CA_L3, CA_L4, CA_L5, CA_L6, CA_L7

[0376]

[0377] In terms of refractive index, the refractive index of the second lens (202) may be the largest among the lenses and may be greater than 1.75, for example, greater than 1.8. Any one or all of the third lens (203), the sixth lens (206), and the eighth lens (208) may have the smallest refractive index among the lenses. For example, the refractive indices of the third lens (203), the sixth lens (206), and the eighth lens (208) may be the smallest among the lenses and may be less than 1.6, for example, less than 1.55. The difference between the maximum refractive index and the minimum refractive index may be 0.2 or more. By providing a lens close to an object as a high refractive index lens, and providing a lens adjacent to a glass lens and a lens adjacent to an image sensor (500) as a low refractive index lens made of a plastic material, the incidence efficiency can be increased, and the refractive power between the lenses made of glass and the lenses made of plastic can be adjusted to guide light to the image sensor (500).

[0378] The refractive index of each lens can satisfy any of the conditions below.

[0379] Condition 1: n1 = n5 > n2, n3, n4, n6, n7, n8

[0380] Condition 2: n2 > n1, n3, n4, n5, n6, n7, n8

[0381] Condition 3: n1, n2, n4, n5, n7 > n3 = n6 = n8

[0382] Condition 4: n2 > n4 = n7 > n1, n3, n5, n6, n8

[0383]

[0384] Comparing the Abbe numbers, the Abbe number of at least one of the first lens (201) and the fifth lens (205) is the largest among the lenses, and may be 60 or more. The Abbe number of at least one of the fourth lens (204) and the seventh lens (207) is the smallest among the lenses, and may be 25 or less. The difference between the maximum refractive index and the minimum Abbe number may be 40 or more. By providing the Abbe number of the fifth lens (205) arranged at the center of the optical system (1100) to be the largest, and the Abbe number of the seventh lens (207) having a low refractive index adjacent to the image sensor (500) to be the smallest, the chromatic dispersion of light traveling between the lenses made of glass and plastic can be controlled, and the chromatic dispersion between the lenses made of glass and plastic can be increased to guide the light to the image sensor (500).

[0385] The Abbe number of each lens can satisfy any of the conditions below.

[0386] Condition 1: v1 = v5 > v2, v3, v4, v6, v7, v8

[0387] Condition 2: v1, v3, v5, v6, v8 > v2 > v4, v7

[0388] Condition 3: v1, v5 > v3 = v6 = v8 > v2, v4, v7

[0389] Condition 4: v1, v2, v3, v5, v6, v8 > v4 = v7

[0390]

[0391] The focal lengths (F1, F3, F4, F7) of the 1st, 3rd, 4th, and 7th lenses (201, 203, 204, and 207) may have negative (-) signs. The 1st, 3rd, 4th, and 7th lenses (201, 203, 204, and 207) may have negative (-) refractive power. The focal lengths (F2, F5, F6, and F8) of the 2nd, 5th, 6th, and 8th lenses (202, 205, 206, and 208) may have positive (+) signs. The 2nd, 5th, 6th, and 8th lenses (202, 205, 206, and 208) may have positive (+) refractive power.

[0392] Additionally, the seventh lens (207) and the eighth lens (208), which are adjacently arranged lenses, can satisfy the following conditions.

[0393] Condition 1: Refractive index of lens with positive refractive power < refractive index of lens with negative refractive power

[0394] Condition 2: Dispersion of a lens with positive refractive power > Dispersion of a lens with negative refractive power

[0395] Here, among the plastic lenses, the eighth lens (208) has positive refractive power and the seventh lens (207) has negative refractive power, so that according to conditions 1 and 2, the refractive index of the eighth lens (208) is smaller than the refractive index of the seventh lens (207), and the dispersion value of the eighth lens (208) is larger than the dispersion value of the seventh lens (207). Chromatic aberration occurring in the plastic lens can be corrected by the plastic lens. In addition, since the seventh lens (207) and the eighth lens (208), which are plastic lenses arranged in succession, satisfy the conditions of a refractive index difference of 0.1 or more and 0.15 or less and an Abbe number difference of 20 or more and 50 or less, the chromatic aberration occurring in the plastic lens can be compensated for by the plastic lens.

[0396] Optical systems suffer from chromatic aberration, and chromatic aberration is corrected by using cemented lenses or two lenses arranged in series. As the temperature changes from low to high, the lenses repeatedly contract and expand. Since lenses made of the same material exhibit the same amount of change in lens characteristics due to temperature changes, it is effective to correct chromatic aberration between lenses made of the same material even when the temperature changes. Therefore, in the second embodiment of the present invention, chromatic aberration occurring in a plastic lens can be corrected by using the seventh lens (207) and the eighth lens (208).

[0397]

[0398] When comparing the focal lengths in absolute values, the focal length of the fourth lens (204) is the largest among the lenses, and may be 55 or more and 65 or less. 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 7 or more and 9 or less.

[0399] The absolute value of the focal length of each lens can satisfy any of the conditions below.

[0400] Condition 1: |f2|, |f4|> |f1| > |f3|, |f5|, |f6|, |f7|, |f8|

[0401] Condition 2: |f4| > |f2| > |f1|, |f3|, |f5|, |f6|, |f7|, |f8|

[0402] Condition 3: |f1|, |f2|, |f4|, |f8| > |f3| > |f5|, |f6|, |f7|

[0403] Condition 4: |f4| > |f1|, |f2|, |f3|, |f5|, |f6|, |f7|, |f8|

[0404] Condition 5: |f1|, |f2|, |f3|, |f4|, |f8| > |f5| > |f6|, |f7|

[0405] Condition 6: |f1|, |f2|, |f3|, |f4|, |f5|, |f7|, |f8| > |f6|

[0406] Condition 7: |f1|, |f2|, |f3|, |f4|, |f5|, |f8| > |f7| > |f6|

[0407] Condition 8: |f1|, |f2|, |f4| > |f8| > |f3|, |f5|, |f6|, |f7|

[0408]

[0409] The thickness (T1) of the first lens (201) may be a difference of 1.3 times or more between the maximum thickness and the minimum thickness, for example, in a range of 1.3 to 1.8 times, and the center thickness (CT1) may be a minimum and the edge thickness (ET1) may be a maximum. The thickness (T2) of the second lens (202) may be a maximum thickness in a range of 1 to 1.5 times the minimum thickness. The second lens (202) may be a maximum center thickness (CT2) and the edge thickness (ET2) may be a minimum. The thickness (T3) of the third lens (203) may be a minimum at the center and a maximum at the edge, and the maximum thickness is in a range of 1.5 to 2 times the minimum thickness. The thickness (T4) of the fourth lens (204) may be a minimum at the center and a maximum at the edge, and the maximum thickness is in a range of 1 to 1.5 times the minimum thickness. The thickness (T5) of the fifth lens (205) may be maximum at the center and minimum at the edge, and the maximum thickness is in the range of 1.3 to 1.5 times the minimum thickness. The thickness (T6) of the sixth lens (206) may be maximum at the center and minimum at the edge, and the maximum thickness is in the range of 2 to 2.5 times the minimum thickness. The thickness (T7) of the seventh lens (207) may be minimum at the center and maximum at the edge, and the maximum thickness is in the range of 1.5 to 2 times the minimum thickness. The thickness (T8) of the eighth lens (208) 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.

[0410] The ratio of the center thickness to the edge thickness of each lens can be referred to as the thickness ratio. When the ratio of the larger to smaller center thickness to the smaller edge thickness is between 2 and 2.5, lens manufacturing is easy and can be advantageous in terms of yield.

[0411] The thickness of each lens can satisfy any of the conditions below.

[0412] Condition 1: 0.3 < CT1 / ET1 < 0.7, 2 < ET1 / CT1 < 2.5

[0413] Condition 2: 1.5 < CT2 / ET2 < 2, 0.3 < ET2 / CT2 < 0.7

[0414] Condition 3: 0.3 < CT3 / ET3 < 0.7, 1.5 < ET3 / CT3 < 2

[0415] Condition 4: 0.8 < CT4 / ET4 < 1.2, 0.5 < ET4 / CT4 < 1

[0416] Condition 5: 1.2 < CT5 / ET5 < 1.5, 0.5 < ET5 / CT5 < 1

[0417] Condition 6: 2 < CT6 / ET6 < 2.5, 0.1 < ET6 / CT6 < 0.5

[0418] Condition 7: 0.3 < CT7 / ET7 < 0.7, 1.5 < ET7 / CT7 < 2

[0419] Condition 8: 2 < CT8 / ET8 < 2.5, 0.1 < ET8 / CT8 < 0.5

[0420] Condition 9: 1 < ΣCT / ΣET < 1.2, 0.5 < ΣET / ΣCT < 1

[0421]

[0422] Among the gaps (G1-G7) between the lenses, the first gap (G1) between the first and second lenses (201, 202) may have a maximum in the center and a minimum in the edge. The second gap (G2) between the second and third lenses (202, 203) may have a minimum in the center and a maximum in the edge. The third gap (G3) between the third and fourth lenses (203, 204) may have a minimum in the edge and a maximum in the center. The fourth gap (G4) between the fourth and fifth lenses (204, 205) may have a minimum in the center and a maximum in the edge. The fifth gap (G5) between the fifth and sixth lenses (205, 206) may have a minimum in the center and a maximum in the edge. The sixth gap (G6) between the sixth and seventh lenses (206, 207) may have a minimum in the center and a maximum in the edge. The seventh gap (G7) between the seventh and eighth lenses (207, 208) may be maximum at the center and minimum at the edge.

[0423]

[0424] FIG. 17, FIG. 19, and FIG. 21 are graphs showing the diffraction MTF (Modulation Transfer Function) at room temperature, low temperature, and high temperature in the optical system of FIG. 12, and are graphs showing the modulation ratio according to the spatial frequency. As shown in FIG. 17, FIG. 19, and FIG. 21, in the second embodiment of the invention, the deviation of the MTF at low temperature or high temperature based on room temperature may be less than 10%, that is, 7% or less.

[0425] FIGS. 18, 20, and 22 are graphs showing aberration characteristics at room temperature, low temperature, and high temperature in the optical system of FIG. 12. In the aberration graphs of FIGS. 18, 20, and 22, spherical aberration (longitudinal spherical aberration), astigmatic field curves, and distortion are measured from left to right. In FIGS. 18, 20, and 22, the X-axis may represent the focal length (mm) and the degree of distortion (%), and the Y-axis may represent the height of the image. In addition, the graph for spherical aberration is a graph for light in wavelength bands of about 435 nm, about 486 nm, about 546 nm, about 587 nm, and about 656 nm, and the graphs for astigmatism and distortion are graphs for light in wavelength bands of about 546 nm. In the aberration diagrams of FIGS. 18, 20, and 22, the closer the curves at room temperature, low temperature, and high temperature are to the Y-axis, the better the aberration correction function can be interpreted. It can be seen that the optical system (1100) according to the second embodiment has measured values ​​close to the Y-axis in almost all areas. 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 in the range of 22 degrees ± 5 degrees or in the range of 18 degrees to 27 degrees, and the high temperature is 85 degrees or higher, for example, in the range of 85 to 105 degrees. Accordingly, it can be seen that the decrease in luminance ratio (modulation) from low temperature to high temperature in FIGS. 18, 20 and 22 is less than 10%, for example, less than 5%, or is almost unchanged.

[0426] Table 6 compares changes in optical characteristics such as EFL, BFL, F number (F#), TTL, and field of view (FOV_H) at room temperature, low temperature, and high temperature in the optical system according to the second embodiment, and it can be seen that the change rate of optical characteristics at low temperature is 5% or less, for example, 3% or less, based on room temperature, and it can be seen that the change rate of optical characteristics at low temperature is 5% or less, for example, 3% or less, based on room temperature.

[0427]

[0428] Room temperature low temperature high temperature low temperature / Room temperature high temperature / Room temperature EFL(F) 5.105.065.1599.21%101.17% BFL 2.882.872.8899.65%100.34% F# 1.601.591.6199.37%101.25% TTL 34.1034.1034.19100.00%100.26% FOV_H 120.00122.08117.51101.73%96.25%

[0429]

[0430] Therefore, as shown in Table 6, it can be seen that the change in optical characteristics according to the temperature change from low temperature to high temperature, for example, the change rate of effective focal length (EFL), TTL, BFL, F number, and field of view (FOV_H) is less than 10%, that is, less than 5%, for example, in the range of 0 to 5%. This means that even if at least one or two or more plastic lenses are used, the design can enable temperature compensation for the plastic lenses, thereby preventing a decrease in the reliability of the optical characteristics.

[0431] 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.

[0432]

[0433] Below, the configuration of an optical system according to a third embodiment of the present invention is described with reference to the drawings.

[0434] FIG. 23 is a side cross-sectional view of an optical system according to the third embodiment and a camera module having the same, FIG. 24 is a table showing the aspherical coefficient value and the conic constant (k) of each lens surface in the optical system according to the third embodiment, FIG. 25 is a table showing the thickness of each lens and the spacing between adjacent lenses in the optical system according to the third embodiment, FIG. 26 is a table showing the Sag values ​​of each lens surface in the optical system according to the third embodiment, FIG. 27 is a table showing the Slope Angle values ​​of each lens surface in the optical system according to the third embodiment, FIG. 28 is a graph showing data on the diffraction MTF (Modulation Transfer Function) at room temperature of the optical system according to the third embodiment, FIG. 29 is a graph showing data on the aberration characteristics of the optical system according to the third embodiment at room temperature, and FIG. 30 is a graph showing data on the diffraction MTF at low temperature of the optical system according to the third embodiment. FIG. 31 is a graph showing data on aberration characteristics at low temperatures of an optical system according to the third embodiment of the present invention, FIG. 32 is a graph showing data on diffraction MTF at high temperatures of an optical system according to the third embodiment of the present invention, and FIG. 33 is a graph showing data on aberration characteristics at high temperatures of an optical system according to the third embodiment of the present invention.

[0435] An optical system according to a third embodiment includes a lens unit, and the lens unit may include a first lens (301) to an eighth lens (308). The first to eighth lenses (301, 302, 303, 304, 305, 306, 307, 308) may be sequentially arranged along an optical axis (OA). Light corresponding to information about an object may pass through the first lens (301) to the eighth lens (308) and a filter (500) and be incident on an image sensor (400).

[0436] The lens section may be arranged in order from the object side to the image side, including a first lens (301), a second lens (302), a third lens (303), a fourth lens (304), a fifth lens (305), an aperture (STOP), a sixth lens (306), a seventh lens (307), and an eighth lens (308).

[0437] In another embodiment, one or more of another lens, a flat plate, and an optical member may be added between the first lens (301) to the eighth lens (308). In addition, one or more of another lens, a flat plate, and an optical member may be added in front of the first lens (301) or behind the eighth lens (308). In addition, one or more of another lens, a flat plate, and an optical member may be added between the aperture (STOP) and the lens, between the lens and the filter (500), and between the filter (500) and the image sensor (400). In this case, the filter (500) may be a flat plate lens. The refractive power of the flat plate lens may be '0'. The refractive power of the flat plate lens may be zero. In addition, a filter layer may be arranged between the aperture (STOP) and the lens, between the lens and the filter (500), and between the filter (500) and the image sensor (400). In this case, the filter layer may be coated to become a filter.

[0438] The first lens (301) may be arranged closest to the object side. The first lens (301) may be arranged farthest from the sensor side. The first lens (301) may have negative (-) refractive power on the optical axis (OA). The first lens (301) may include a plastic material or a glass material, and may be made of glass, for example. The first lens (301) made of glass can reduce changes in the center position and radius of curvature due to temperature changes in the surrounding environment, and can protect the incident side of the optical system (1000).

[0439] The first surface (S1) on the object side of the first lens (301) with respect to the optical axis may be convex, and the second surface (S2) on the sensor side may be concave. The first lens (301) may have a meniscus shape that is convex toward the object side. The first lens (301) may be made of glass and may have a spherical surface. At least one or both of the first surface (S1) and the second surface (S2) may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0440] The refractive index (n1) of the first lens (301) can satisfy the condition of n1>1.6 or n1>1.61. The radius of curvature of the first and second lenses (301, 302) can be increased, and lens manufacturing can be facilitated. If the refractive index (n1) of the first lens (301) is smaller than the condition, the lens surface must be formed to be sharply concave or convex in order to increase the refractive power of the first and second lenses (301, 302). In this case, lens manufacturing is not easy, the lens defect rate increases, and it may cause a decrease in yield.

[0441]

[0442] The second lens (302) may be arranged second from the object side. The second lens (302) may be arranged seventh from the sensor side. The second lens (302) may be arranged between the first lens (301) and the third lens (303). The second lens (302) may have positive (+) refractive power in the optical axis (OA). The second lens (302) may include a plastic or glass material. For example, the second lens (302) may be provided as a glass mold material.

[0443] The third surface (S3) on the object side of the second lens (302) may be convex with respect to the optical axis (OA), and the fourth surface (S4) on the sensor side may be concave. The second lens (302) may have a meniscus shape that is convex toward the object side. The second lens (302) may have a meniscus shape that is concave toward the sensor side. The second lens (302) is made of a glass mold material and may be aspherical. At least one or both of the third surface (S3) and the fourth surface (S4) may be aspherical. The aspherical coefficients of the third and fourth surfaces (S3, S4) may be provided as S1 and S2 of L2 in FIG. 24. 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.

[0444]

[0445] The third lens (303) may be arranged third from the object side. The third lens (303) may be arranged sixth from the sensor side. The third lens (303) may be arranged between the second lens (302) and the fourth lens (304). The third lens (303) may have negative (-) refractive power in the optical axis (OA). The third lens (303) may include a plastic or glass material. For example, the third lens (303) may be provided as a plastic material.

[0446] The fifth surface (S5) on the object side of the third lens (303) with respect to the optical axis may be convex, and the sixth surface (S6) on the sensor side may be concave. The third lens (303) may have a meniscus shape that is convex toward the object side. The third lens (303) may be made of a plastic material and may be aspherical. At least one or both of the fifth surface (S5) and the sixth surface (S6) may be aspherical. The aspherical coefficients of the fifth and sixth surfaces (S5, S6) may be provided as S5 and S6 of L3 in FIG. 24.

[0447] The fifth surface (S5) of the third lens (303) may include a critical point from the optical axis (OA) to the end of the effective area. When the fifth surface (S5) has a critical point, it may be located in a range of 80% to 90%, preferably 85% to 88%, of the effective radius (r31) from the optical axis (OA). The critical point of the fifth surface (S5) may be located in a range of 4.0 mm to 4.5 mm, preferably 4.2 mm to 4.3 mm from the optical axis (OA). The sixth surface (S6) of the third lens (303) may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0448]

[0449] The fourth lens (304) may be arranged fourth from the object side. The fourth lens (304) may be arranged fifth from the sensor side. The fourth lens (304) may be arranged between the third lens (303) and the fifth lens (305). The fourth lens (304) may have positive (+) or negative (-) refractive power on the optical axis (OA). The fourth lens (304) may have negative (-) refractive power. The fourth lens (304) may include a plastic or glass material. For example, the fourth lens (304) may be provided as a plastic material.

[0450] The seventh surface (S7) on the object side of the fourth lens (304) with respect to the optical axis may be convex, and the eighth surface (S8) on the sensor side may be concave. The fourth lens (304) may have a meniscus shape that is convex toward the object side. The fourth lens (304) may have a meniscus shape that is concave toward the sensor side. The fourth lens (304) may be made of a plastic material and may be aspherical. At least one or both of the seventh surface (S7) and the eighth surface (S8) may be aspherical. The aspherical coefficients of the seventh and eighth surfaces (S7, S8) may be provided as S1 and S2 of L4 in FIG. 24. At least one or both of the seventh surface (S7) and the eighth surface (S8) may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0451]

[0452] The fifth lens (305) may be arranged as the fifth lens from the object side. The fifth lens (305) may be arranged as the fourth lens from the sensor side. The fifth lens (305) may be arranged between the fourth lens (304) and the sixth lens (306). The fifth lens (305) may have positive (+) or negative (-) refractive power on the optical axis (OA). The fifth lens (305) may have positive (+) refractive power. The fifth lens (305) may include a plastic or glass material. For example, the fifth lens (305) may be provided as a glass material.

[0453] With respect to the optical axis (OA), the ninth surface (S9) on the object side of the fifth lens (305) may be convex, and the tenth surface (S10) on the sensor side may be convex. The fifth lens (305) may have a shape in which both sides are convex. The fifth lens (305) may be made of glass 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) may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0454] The aperture (Stop) may be arranged around the sensor-side tenth surface (S10) of the fifth lens (305). The aperture (Stop) may be arranged around the object-side eleventh surface (S11) of the sixth lens (306). The aperture can reduce the TTL within the field of view range, and the optical system can be miniaturized. Accordingly, a decrease in the yield by weight of the optical system can be prevented, and production efficiency can be improved. In addition, the optical system can be miniaturized by reducing the TTL within the horizontal field of view (FOV_H) of 100 to 130 degrees.

[0455]

[0456] The sixth lens (306) may be arranged as the sixth lens from the object side. The sixth lens (306) may be arranged as the third lens from the sensor side. The sixth lens (306) may be arranged between the fifth lens (305) and the seventh lens (307). The sixth lens (306) may have positive (+) or negative (-) refractive power on the optical axis (OA). The sixth lens (306) may have positive (+) refractive power. The sixth lens (306) may include a plastic or glass material. For example, the sixth lens (306) may be provided as a plastic material.

[0457] With respect to the optical axis (OA), the object-side eleventh surface (S11) of the sixth lens (306) may be convex, and the sensor-side twelfth surface (S12) may be convex. The sixth lens (306) may have a convex shape on both sides. The sixth lens (306) may be made of a plastic material and may be aspherical. At least one or both of the eleventh surface (S11) and the twelfth surface (S12) may be aspherical. The aspherical coefficients of the eleventh and twelfth surfaces (S11, S12) may be provided as S1 and S2 of L6 in FIG. 24. At least one or both of the eleventh surface (S11) and the twelfth surface (S12) may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0458]

[0459] The seventh lens (307) may be arranged as the seventh lens from the object side. The seventh lens (307) may be arranged as the second lens from the sensor side. The seventh lens (307) may be arranged between the sixth lens (306) and the eighth lens (308). The seventh lens (307) may have positive (+) or negative (-) refractive power on the optical axis (OA). The seventh lens (307) may have negative (-) refractive power. The seventh lens (307) may include a plastic or glass material. For example, the seventh lens (307) may be provided as a plastic material.

[0460] With respect to the optical axis (OA), the 13th surface (S13) on the object side of the seventh lens (307) may be concave, and the 14th surface (S14) on the sensor side may be concave. The seventh lens (307) may have a concave shape on both sides. The seventh lens (307) may be made of a plastic material and may be aspherical. At least one or both of the 13th surface (S13) and the 14th surface (S14) may be aspherical. The aspherical coefficients of the 13th and 14th surfaces (S13, S14) may be provided as S13 and S14 of L7 in FIG. 24.

[0461]

[0462] The eighth lens (308) may be positioned furthest from the object side. The eighth lens (308) may be positioned closest to the image sensor (500). The eighth lens (308) may have positive (+) or negative (-) refractive power on the optical axis (OA). The eighth lens (308) may have positive (+) refractive power. The eighth lens (308) may include a plastic or glass material. For example, the eighth lens (308) may be provided as a plastic material.

[0463] With respect to the optical axis (OA), the 15th surface (S15) on the object side of the 8th lens (308) may be convex, and the 16th surface (S16) on the sensor side may be concave. The 8th lens (308) may have a meniscus shape that is convex toward the object side. The 8th lens (308) may have a meniscus shape that is concave toward the sensor side. At least one or both of the 15th surface (S15) and the 16th surface (S16) may be aspherical. The aspherical coefficients of the 15th and 16th surfaces (S15, S16) may be provided as S15 and S16 of L8 in FIG. 24.

[0464] The eighth lens (308) may be a plastic lens closest to the image sensor (500). In addition, by arranging two or more plastic lenses adjacent to the image sensor (500), aberrations such as spherical aberration and chromatic aberration can be improved by the lens surface having an aspherical surface, and the influence on the resolution can be controlled. In addition, by arranging the plastic lens as the lens adjacent to the image sensor (500), it can be insensitive to assembly tolerances compared to a glass lens. In other words, being insensitive to assembly tolerances means that even if the assembly is slightly different from the design during assembly, the optical performance may not be significantly affected. In addition, by providing the two lenses (307, 308) adjacent to the image sensor (500) as plastic, the optical performance can be improved by the lens surface having an aspherical surface, and for example, aberration characteristics can be improved and resolution deterioration can be prevented.

[0465]

[0466] LensSurfaceRadiusThicknessndvdSemiApertureFocal length1S137.5432.0001.620363.394910.154-15.0294S27.3163.0306.2212S322 .6032.0361.829724.03945.90334.7491S4100.3680.2415.3963S54.5071.8001.5 38855.97984.992-11.1454S62.2142.5903.6324S749.4622.9851.663321.24143. 612-69.9200S823.3590.5003.3545S915.1702.9711.620363.39493.30010.2229S 10-10.0790.5003.445STOP-1.8403.3286S117.1653.3611.538855.97984.1008.0 478S12-9.1780.5004.1257S13-6406.7881.5001.663321.24144.012-9.3065S146 .1801.8954.1038S156.8143.2311.538855.97984.56314.7731S1639.4841.6204.804FilterS17Infinity0.5004.447S18Infinity1.0004.394ImageInfinity0.000

[0467]

[0468] Table 7 shows the surface number (Surface), radius of curvature (Radius), center thickness of each lens or distance between lens surfaces (Thickness), refractive index (Index,nd), Abbe number (Abbe,vd), effective radius (Semi Aperture), and focal length (Fcoal length) of the lens according to the third embodiment of the present invention. At this time, the unit of the radius of curvature and thickness or distance may be mm.

[0469]

[0470] Third embodiment Third embodiment TTL34.1000ET14.0656F5.1000ET21.4995F_LG1-5.542ET33.2666F_LG26.625ET43.0748Fno1.6000ET52.0100FOV_H120.0000ET61.4646EPD3.1875ET72.7263BFL1.0000ET81.4887TD(L1S1 ~L8S2)33.1000ImgH4.0320SD(Stop~L8S2)14.4466

[0471]

[0472] Table 8 shows the characteristics of an imaging lens according to a third embodiment of the present invention.

[0473] TTL means the optical axis distance from the object-side vertex of the first lens (301) to the image surface, SD means the optical axis distance from the aperture (STOP) to the image-side surface of the ninth lens (309), TD means the optical axis distance from the object-side vertex of the first lens (301) to the image-side surface of the ninth lens (309), F means the total focal length, F_LG1 means the composite focal length of the first lens (301) to the third lens (303) in the object-side direction of the aperture (STOP), F_LG2 means the composite focal length of the fourth lens (304) to the ninth lens (309) in the image-side direction of the aperture (STOP), Fno means the ratio of the focal length of the lens to the effective diameter, ImgH means the distance from the optical axis (OA) to the diagonal end of the image sensor (400) or 1 / 2 of the maximum diagonal length, and FOV_H means It refers to the horizontal angle of view of the optical system, EPD refers to the diameter of the entrance pupil (effective aperture), BFL refers to the optical axis distance from the image side surface to the image surface of the eighth lens (308), and ET1 to ET8 refer to the thickness of the edge area of ​​each lens.

[0474]

[0475] The center thicknesses of the first to eighth lenses (301 to 308) are represented by CT1 to CT8, the edge thicknesses at the ends of the effective areas of each lens are represented by ET1 to ET8, the center gap between two adjacent lenses is represented by CG1 to CG7, and the edge gaps between the edges of each lens are represented by EG1 to EG7. The BFL (Back focal length) is the optical axis distance from the image sensor (500) to the center of the last lens. The TTL is the optical axis distance from the center of the first surface (S1) of the first lens (301) to the upper surface of the image sensor (500).

[0476] As shown in Fig. 23, among the lenses of the lens unit of the third embodiment, the lens surfaces of the second, third, fourth, sixth, seventh, and eighth lenses (302, 302, 304, 306, 307, and 308) may include aspherical surfaces having a 30th-order aspherical surface coefficient. For example, the second, third, fourth, sixth, seventh, and eighth lenses (302, 302, 304, 306, 307, and 308) may include lens surfaces having a 30th-order aspherical surface coefficient. As described above, the aspherical surface having a 30th-order aspherical surface coefficient (a value other than "0") can significantly change the aspherical shape of the periphery, and thus can effectively correct the optical performance of the periphery of the field of view (FOV).

[0477] The thickness (T1-T8) of the first to eighth lenses (301-308) and the spacing (G1-G7) between adjacent two lenses can be set. As shown in Fig. 25, the thickness (T1-T8) of each lens in the Y-axis direction can be expressed at intervals of 0.1 mm or 0.2 mm or more, and the spacing (G1-G7) between each lens can be expressed at intervals of 0.1 mm or 0.2 mm or more.

[0478] When comparing the absolute values ​​of the curvature radii of each lens, the curvature radii of the 13th surface (S13) of the 7th lens (307) on the optical axis (OA) may be the largest among the lenses, and the curvature radii of the 6th surface (S6) of the 3rd lens (303) may be the smallest among the lenses.

[0479] Since the effective diameter of a plastic lens is smaller than that of a glass lens, the lens placed on the object side of the plastic lens can have a strong refractive power to refract light through the plastic lens. In addition, the radius of curvature of the lens surface can be small to increase the refractive power.

[0480] The absolute value of the curvature radius of the first surface (S1) of the first lens (301) may be greater than the absolute value of the curvature radius of the second surface (S2). The absolute value of the curvature radius of the third surface (S3) of the second lens (302) may be less than the absolute value of the curvature radius of the fourth surface (S4). The absolute value of the curvature radius of the fifth surface (S5) of the third lens (303) may be greater than the absolute value of the curvature radius of the sixth surface (S6). The absolute value of the curvature radius of the seventh surface (S7) of the fourth lens (304) may be greater than the absolute value of the curvature radius of the eighth surface (S8). The absolute value of the curvature radius of the ninth surface (S9) of the fifth lens (305) may be greater than the absolute value of the curvature radius of the tenth surface (S10). The absolute value of the curvature radius of the eleventh surface (S11) of the sixth lens (306) may be smaller than the absolute value of the curvature radius of the twelfth surface (S12). The absolute value of the curvature radius of the thirteenth surface (S13) of the seventh lens (307) may be larger than the absolute value of the curvature radius of the fourteenth surface (S14). The absolute value of the curvature radius of the fifteenth surface (S15) of the eighth lens (308) may be smaller than the absolute value of the curvature radius of the sixteenth surface (S16).

[0481] The ratio of the radius of curvature of each lens can satisfy the following conditions.

[0482] Condition 1: 5 < |L1R1 / L1R2| < 6

[0483] Condition 2: 0.1 < |L2R1 / L2R2| < 0.5

[0484] Condition 3: 1.5 < |L3R1 / L3R2| < 2.5

[0485] Condition 4: 2 < L4R1 / L4R2 < 2.5

[0486] Condition 5: 1 < |L5R1 / L5R2| < 2

[0487] Condition 6: 0.5 < |L6R1 / L6R2| < 1

[0488] Condition 7: 1000 < |L7R1 / L7R2| < 1100

[0489] Condition 8: 0.1 < |L8R1 / L8R2| < 0.5

[0490]

[0491] When describing the central thickness (CT) of the lenses based on the optical axis, the central thickness (CT5) of the fifth lens (305) is the largest among the lenses, and the central thickness (CT7) of the seventh lens (307) is the smallest among the lenses. The difference between the maximum and minimum central thicknesses among the lenses may be in the range of 1.5 mm or more and 2.5 mm or less.

[0492] The central thickness of each lens may satisfy any one of the following conditions:

[0493] Condition 1: CT2, CT4, CT5, CT6, CT8 > CT1 > CT3, CT7

[0494] Condition 2: CT4, CT5, CT6, CT8 > CT2 > CT1, CT3, CT7

[0495] Condition 3: CT1, CT2, CT4, CT5, CT6, CT8 > CT3 > CT7

[0496] Condition 4: CT6, CT8 > CT4 > CT1, CT2, CT3, CT5, CT7

[0497] Condition 5: CT4, CT6, CT8 > CT5 > CT1, CT2, CT3, CT7

[0498] Condition 6: CT6 > CT1, CT2, CT3, CT4, CT5, CT7, CT8

[0499] Condition 7: CT1, CT2, CT3, CT4, CT5, CT6, CT8 > CT7

[0500] Condition 8: CT6 > CT8 > CT1, CT2, CT3, CT4, CT5, CT7

[0501]

[0502] When describing the center spacing (CG) between the lenses, the center spacing (CG1) between the first lens (301) and the second lens (302) may be maximum, and at least one of the center spacing (CG4) between the fourth and fifth lenses (304, 305) and the center spacing (CG6) between the sixth and seventh lenses (306, 307) may be minimum. The difference between the maximum center spacing and the minimum center spacing among the spaced lens spacings may be 2 mm or more, for example, in the range of 2.5 mm to 3.5 mm.

[0503] The center spacing between each lens can satisfy the conditions below.

[0504] Condition 1: CG1 > CG2, CG3, CG4, CG5, CG6, CG7

[0505] Condition 2: CG1, CG3, CG5, CG7 > CG2 > CG4, CG6

[0506] Condition 3: CG1 > CG3 > CG2, CG4, CG5, CG6, CG7

[0507] Condition 4: CG1, CG2, CG3, CG5, CG7 > CG4 = CG6

[0508] Condition 5: CG1, CG3 > CG5 > CG2, CG4, CG6, CG7

[0509] Condition 6: CG1, CG3, CG5 > CG7 > CG2, CG4, CG6

[0510]

[0511] Regarding the effective diameter, the lens having the maximum effective diameter may be a glass lens. The lens having the maximum effective diameter may be the first lens (301). Here, the effective diameter is the average of the effective diameters on the object side and the sensor side of each lens. The lens surface having the maximum effective diameter may be the first surface (S1) of the first lens (301).

[0512] The lens having the minimum effective diameter may be a lens arranged between the first lens (301) and the aperture (STOP). The lens having the minimum effective diameter may be the fifth lens (305). The lens surface having the minimum effective diameter may be the ninth surface (S9) of the fifth lens (305). The effective diameter of the plastic lens may be smaller than that of the glass lens. The plastic lens may be arranged adjacent to the image sensor.

[0513] The effective diameter of each lens can satisfy any one of the conditions below.

[0514] Condition 1: CA_L1 > CA_L2, CA_L3, CA_L4, CA_L5, CA_L6, CA_L7, CA_L8

[0515] Condition 2: CA_L1 > CA_L2 > CA_L3, CA_L4, CA_L5, CA_L6, CA_L7, CA_L8

[0516] Condition 3: CA_L1, CA_L2, CA_L8 > CA_L3 > CA_L4, CA_L5, CA_L6, CA_L7

[0517] Condition 4: CA_L1, CA_L2, CA_L3, CA_L6, CA_L7, CA_L8 > CA_L4 > CA_L5

[0518] Condition 5: CA_L1, CA_L2, CA_L3, CA_L4, CA_L6, CA_L7, CA_L8 > CA_L5

[0519] Condition 6: CA_L1, CA_L2, CA_L3, CA_L8 > CA_L6 > CA_L4, CA_L5, CA_L7

[0520] Condition 7: CA_L1, CA_L2, CA_L3, CA_L6, CA_L8 > CA_L7 > CA_L4, CA_L5

[0521] Condition 8: CA_L1, CA_L2 > CA_L8 > CA_L3, CA_L4, CA_L5, CA_L6, CA_L7

[0522]

[0523] In terms of refractive index, the refractive index of the second lens (302) may be the largest among the lenses and may be greater than 1.75, for example, greater than 1.8. Any one or all of the third lens (303), the sixth lens (306), and the eighth lens (308) may have the smallest refractive index among the lenses. For example, the refractive indices of the third lens (303), the sixth lens (306), and the eighth lens (308) may be the smallest among the lenses and may be less than 1.6, for example, less than 1.55. The difference between the maximum refractive index and the minimum refractive index may be 0.2 or more. By providing a lens close to an object as a high refractive index lens, and providing a lens adjacent to a glass lens and a lens adjacent to an image sensor (500) as a low refractive index lens made of a plastic material, the incidence efficiency can be increased, and the refractive power between the lenses made of glass and the lenses made of plastic can be adjusted to guide light to the image sensor (500).

[0524] The refractive index of each lens can satisfy any of the conditions below.

[0525] Condition 1: n1 = n5 > n2, n3, n4, n6, n7, n8

[0526] Condition 2: n2 > n1, n3, n4, n5, n6, n7, n8

[0527] Condition 3: n1, n2, n4, n5, n7 > n3 = n6 = n8

[0528] Condition 4: n2 > n4 = n7 > n1, n3, n5, n6, n8

[0529]

[0530] Comparing the Abbe numbers, the Abbe number of at least one of the first lens (301) and the fifth lens (305) is the largest among the lenses, and may be 60 or more. The Abbe number of at least one of the fourth lens (304) and the seventh lens (307) is the smallest among the lenses, and may be 25 or less. The difference between the maximum refractive index and the minimum Abbe number may be 40 or more. By providing the Abbe number of the fifth lens (305) arranged at the center of the optical system (1200) to be the largest, and the Abbe number of the seventh lens (307) having a low refractive index adjacent to the image sensor (500) to be the smallest, the chromatic dispersion of light traveling between the lenses made of glass and plastic can be controlled, and the chromatic dispersion between the lenses made of glass and plastic can be increased to guide the light to the image sensor (500).

[0531] The Abbe number of each lens can satisfy any of the conditions below.

[0532] Condition 1: v1 = v5 > v2, v3, v4, v6, v7, v8

[0533] Condition 2: v1, v3, v5, v6, v8 > v2 > v4, v7

[0534] Condition 3: v1, v5 > v3 = v6 = v8 > v2, v4, v7

[0535] Condition 4: v1, v2, v3, v5, v6, v8 > v4 = v7

[0536]

[0537] The focal lengths (F1, F3, F4, F7) of the first, third, fourth, and seventh lenses (301, 303, 304, and 307) may have negative (-) signs. The first, third, fourth, and seventh lenses (301, 303, 304, and 307) may have negative (-) refractive power. The focal lengths (F2, F5, F6, and F8) of the second, fifth, sixth, and eighth lenses (302, 305, 306, and 308) may have positive (+) signs. The second, fifth, sixth, and eighth lenses (302, 305, 306, and 308) may have positive (+) refractive power.

[0538] Additionally, the seventh lens (307) and the eighth lens (308), which are adjacently arranged lenses, can satisfy the following conditions.

[0539] Condition 1: Refractive index of lens with positive refractive power < refractive index of lens with negative refractive power

[0540] Condition 2: Dispersion of a lens with positive refractive power > Dispersion of a lens with negative refractive power

[0541] Here, among the plastic lenses, the eighth lens (308) has positive refractive power and the seventh lens (307) has negative refractive power, so that according to conditions 1 and 2, the refractive index of the eighth lens (308) is smaller than the refractive index of the seventh lens (307), and the dispersion value of the eighth lens (308) is larger than the dispersion value of the seventh lens (307). The chromatic aberration occurring in the plastic lens can be corrected by the plastic lens. In addition, since the seventh lens (307) and the eighth lens (308), which are plastic lenses arranged in succession, satisfy the conditions of a refractive index difference of 0.1 or more and 0.15 or less and an Abbe number difference of 20 or more and 50 or less, the chromatic aberration occurring in the plastic lens can be compensated for by the plastic lens.

[0542] Optical systems suffer from chromatic aberration, and chromatic aberration is corrected by using cemented lenses or two lenses arranged in series. As the temperature changes from low to high, the lenses contract and expand repeatedly. Since lenses made of the same material exhibit the same amount of change in lens characteristics due to temperature changes, it is effective to correct chromatic aberration between lenses made of the same material even when the temperature changes. Therefore, in the third embodiment of the present invention, chromatic aberration occurring in a plastic lens can be corrected by using the seventh lens (307) and the eighth lens (308).

[0543]

[0544] When comparing the focal lengths in absolute values, the focal length of the fourth lens (304) is the largest among the lenses, and may be 55 or more and 65 or less. The focal length of the sixth lens (306) is the smallest among the lenses, and the absolute value of the focal length of the sixth lens (306) may be 7 or more and 9 or less.

[0545] The absolute value of the focal length of each lens can satisfy any of the conditions below.

[0546] Condition 1: |f2|, |f4|> |f1| > |f3|, |f5|, |f6|, |f7|, |f8|

[0547] Condition 2: |f4| > |f2| > |f1|, |f3|, |f5|, |f6|, |f7|, |f8|

[0548] Condition 3: |f1|, |f2|, |f4|, |f8| > |f3| > |f5|, |f6|, |f7|

[0549] Condition 4: |f4| > |f1|, |f2|, |f3|, |f5|, |f6|, |f7|, |f8|

[0550] Condition 5: |f1|, |f2|, |f3|, |f4|, |f8| > |f5| > |f6|, |f7|

[0551] Condition 6: |f1|, |f2|, |f3|, |f4|, |f5|, |f7|, |f8| > |f6|

[0552] Condition 7: |f1|, |f2|, |f3|, |f4|, |f5|, |f8| > |f7| > |f6|

[0553] Condition 8: |f1|, |f2|, |f4| > |f8| > |f3|, |f5|, |f6|, |f7|

[0554]

[0555] The thickness (T1) of the first lens (301) may be a difference of at least twice the maximum thickness and the minimum thickness, for example, in a range of 2 to 2.5 times, and the center thickness (CT1) may be a minimum and the edge thickness (ET1) may be a maximum. The thickness (T2) of the second lens (302) may be a maximum thickness in a range of 1 to 1.5 times the minimum thickness. The second lens (302) may have a center thickness (CT2) that is a maximum and the edge thickness (ET2) that is a minimum. The thickness (T3) of the third lens (303) may be a minimum at the center and a maximum at the edge, and the maximum thickness is a range of 1.5 to 2 times the minimum thickness. The thickness (T4) of the fourth lens (304) may be a minimum at the center and a maximum at the edge, and the maximum thickness is a range of 1 to 1.5 times the minimum thickness. The thickness (T5) of the fifth lens (305) may be maximum at the center and minimum at the edge, and the maximum thickness is in the range of 1.2 to 1.5 times the minimum thickness. The thickness (T6) of the sixth lens (306) may be maximum at the center and minimum at the edge, and the maximum thickness is in the range of 2 to 2.5 times the minimum thickness. The thickness (T7) of the seventh lens (307) may be minimum at the center and maximum at the edge, and the maximum thickness is in the range of 1.5 to 2 times the minimum thickness. The thickness (T8) of the eighth lens (308) may be maximum at the center and minimum at the edge, and the maximum thickness is in the range of 1 to 1.2 times the minimum thickness.

[0556] The ratio of the center thickness to the edge thickness of each lens can be referred to as the thickness ratio. When the ratio of the larger to smaller center thickness to the smaller edge thickness is between 2 and 2.5, lens manufacturing is easy and can be advantageous in terms of yield.

[0557] The thickness of each lens can satisfy any of the conditions below.

[0558] Condition 1: 0.3 < CT1 / ET1 < 0.7, 2 < ET1 / CT1 < 2.5

[0559] Condition 2: 1 < CT2 / ET2 < 1.5, 0.5 < ET2 / CT2 < 1

[0560] Condition 3: 0.3 < CT3 / ET3 < 0.7, 1.5 < ET3 / CT3 < 2

[0561] Condition 4: 0.8 < CT4 / ET4 < 1.2, 0.8 < ET4 / CT4 < 1.2

[0562] Condition 5: 1.2 < CT5 / ET5 < 1.5, 0.5 < ET5 / CT5 < 1

[0563] Condition 6: 2 < CT6 / ET6 < 2.5, 0.1 < ET6 / CT6 < 0.5

[0564] Condition 7: 0.3 < CT7 / ET7 < 0.7, 1.5 < ET7 / CT7 < 2

[0565] Condition 8: 2 < CT8 / ET8 < 2.5, 0.1 < ET8 / CT8 < 0.5

[0566] Condition 9: 1 < ΣCT / ΣET < 1.2, 0.5 < ΣET / ΣCT < 1

[0567]

[0568] Among the gaps (G1-G7) between the lenses, the first gap (G1) between the first and second lenses (301, 302) may have a maximum in the center and a minimum in the edge. The second gap (G2) between the second and third lenses (302, 303) may have a minimum in the center and a maximum in the edge. The third gap (G3) between the third and fourth lenses (303, 304) may have a minimum in the edge and a maximum in the center. The fourth gap (G4) between the fourth and fifth lenses (304, 305) may have a minimum in the center and a maximum in the edge. The fifth gap (G5) between the fifth and sixth lenses (305, 306) may have a minimum in the center and a maximum in the edge. The sixth gap (G6) between the sixth and seventh lenses (306, 307) may have a minimum in the center and a maximum in the edge. The seventh gap (G7) between the seventh and eighth lenses (307, 308) may be maximum at the center and minimum at the edge.

[0569]

[0570] FIGS. 28, 30, and 32 are graphs showing the diffraction MTF (Modulation Transfer Function) at room temperature, low temperature, and high temperature in the optical system of FIG. 23, and are graphs showing the modulation ratio according to spatial frequency. As shown in FIGS. 28, 30, and 32, in the third embodiment of the invention, the deviation of the MTF at low temperature or high temperature based on room temperature may be less than 10%, that is, 7% or less.

[0571] FIGS. 29, 31, and 33 are graphs showing aberration characteristics at room temperature, low temperature, and high temperature in the optical system of FIG. 23. In the aberration graphs of FIGS. 29, 31, and 33, spherical aberration (longitudinal spherical aberration), astigmatic field curves, and distortion are measured from left to right. In FIGS. 29, 31, and 33, the X-axis may represent the focal length (mm) and the degree of distortion (%), and the Y-axis may represent the height of the image. In addition, the graph for spherical aberration is a graph for light in wavelength bands of about 435 nm, about 486 nm, about 546 nm, about 587 nm, and about 656 nm, and the graphs for astigmatism and distortion are graphs for light in wavelength bands of about 546 nm. In the aberration diagrams of FIGS. 29, 31, and 33, the closer the curves at room temperature, low temperature, and high temperature are to the Y-axis, the better the aberration correction function can be interpreted. It can be seen that the optical system (1200) according to the third embodiment has measured values ​​close to the Y-axis in almost all areas. That is, the optical system (1200) according to the third 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 in the range of 22 degrees ± 5 degrees or in the range of 18 degrees to 27 degrees, and the high temperature is 85 degrees or higher, for example, in the range of 85 to 305 degrees. Accordingly, it can be seen that the decrease in luminance ratio (modulation) from low temperature to high temperature in Figs. 29, 31 and 33 is less than 10%, for example, 5% or less, or is almost unchanged.

[0572] Table 9 compares changes in optical characteristics such as EFL, BFL, F number (F#), TTL, and field of view (FOV_H) at room temperature, low temperature, and high temperature in the optical system according to the third embodiment, and it can be seen that the change rate of optical characteristics at low temperature is 5% or less, for example, 3% or less, based on room temperature, and it can be seen that the change rate of optical characteristics at low temperature is 5% or less, for example, 3% or less, based on room temperature.

[0573]

[0574] Room temperature low temperature high temperature low temperature / Room temperature high temperature / Room temperature EFL(F) 5.105.055.1699.01%102.17% BFL 3.123.123.13100.00%100.32% F# 1.601.591.6199.37%101.25% TTL 34.1034.0334.1999.79%100.47% FOV_H 120.00122.18117.39101.81%96.07%

[0575]

[0576] Therefore, as shown in Table 9, it can be seen that the change in optical characteristics according to the temperature change from low temperature to high temperature, for example, the change rate of effective focal length (EFL), TTL, BFL, F number, and field of view (FOV_H) is 10% or less, that is, 5% or less, for example, in the range of 0 to 5%. This means that even if at least one or two or more plastic lenses are used, the design can enable temperature compensation for the plastic lenses, thereby preventing a decrease in the reliability of the optical characteristics.

[0577] The optical system of the third embodiment disclosed above can effectively control aberration characteristics such as chromatic aberration and distortion aberration, and can have good optical performance not only at the center of the field of view (FOV) but also at the periphery.

[0578]

[0579] The optical systems (1000, 1100, 1200) according to the first to third embodiments disclosed above can satisfy at least one or two or more of the mathematical equations described below. Accordingly, the optical systems (1000, 1100, 1200) according to the first to third embodiments can have improved optical characteristics. For example, when the optical systems (1000, 1100, 1200) satisfy at least one mathematical equation, the optical systems (1000, 1100, 1200) 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. In addition, the optical systems (1000, 1100, 1200) can have improved resolution. In addition, the thickness of the lens on the optical axis (OA) and the spacing between adjacent lenses on the optical axis (OA) described in the mathematical formulas may refer to the first to third embodiments disclosed above.

[0580]

[0581]

[0582] [Mathematical Formula 1]

[0583] 20 < L1R2 < 50

[0584] In mathematical expression 1, L1R2 is the radius of curvature of the sensor side (second surface (S2)) of the first lens (101, 201, 301). When mathematical expression 1 is satisfied, the gap between the first lens (101, 201, 301) and the second lens (102, 202, 302) can be secured when assembling the lenses, and assembly can be facilitated. In addition, when mathematical expression 1 is satisfied, the influence on incident light and TTL can be controlled. In the first embodiment, mathematical expression 1 can preferably satisfy 20 < L1R2 < 30, in the second embodiment, mathematical expression 1 can preferably satisfy 40 < L1R2 < 50, and in the third embodiment, mathematical expression 1 can preferably satisfy 30 < L1R2 < 40.

[0585]

[0586] [Equation 2]

[0587] 1.7 < n2 < 1.9

[0588] In mathematical expression 2, n2 is the refractive index of the second lens (102, 202, 302). In the optical system (1000, 1100, 1200), the lens closest to the object side of the plastic material lens is made of glass, and when it is a high refractive index lens, it can maintain optical performance according to temperature changes. In the first to third embodiments, mathematical expression 2 can preferably satisfy 1.8 < n2 < 1.9.

[0589]

[0590] [Equation 3]

[0591] 20 < v2 < 30

[0592] In mathematical expression 3, v2 is the Abbe number of the second lens (102, 202, 302). In the optical system (1000, 1100, 1200), the lens closest to the object side of the plastic material lens is made of glass, and when it is a high-dispersion lens, it can maintain optical performance according to temperature changes. In the first to third embodiments, mathematical expression 3 can preferably satisfy 22 < v2 < 27.

[0593]

[0594] [Equation 4]

[0595] 0 < CG1 / ΣCG < 0.5

[0596] In mathematical expression 4, CG1 is the center spacing between the first lens (101, 201, 301) and the second lens (102, 202, 302), and ΣCG is the sum of the spacings between adjacent lenses. When mathematical expression 4 is satisfied, the light emitted from the first lens (101, 201, 301), which has a large influence in the entire optical system, sets an optical path for entering the remaining lenses, and the optical system can have good optical performance at the set angle of view and focal length. In the first to third embodiments, mathematical expression 4 can preferably satisfy 0 < CG1 / ΣCG < 0.3.

[0597]

[0598] [Equation 5]

[0599] 0 < CG1 / ΣCT < 0.5

[0600] In mathematical expression 5, CG1 is the center spacing between the first lens (101, 201, 301) and the second lens (102, 202, 302), and ΣCT is the sum of the center thicknesses of the lenses. When mathematical expression 5 is satisfied, the light emitted from the first lens (101, 201, 301), which has a large influence in the entire optical system, sets an optical path for entering the remaining lenses, and the optical system can have good optical performance at the set angle of view and focal length. In the first to third embodiments, mathematical expression 5 can preferably satisfy 0 < CG1 / ΣCT < 0.2.

[0601]

[0602] [Equation 6]

[0603] 0 < CG1 / TTL < 0.3

[0604] In mathematical expression 6, CG1 is the center spacing between the first lens (101, 201, 301) and the second lens (102, 202, 302), and the relationship of TTL, which is the distance (mm) from the center of the first surface (S1) of the first lens (101, 201, 301) to the upper surface of the image sensor (500) on the optical axis (OA), can be set. When mathematical expression 6 is satisfied, the light emitted from the first lens (101, 201, 301), which has a large influence in the entire optical system, sets an optical path for entering the remaining lenses, and the optical system can have good optical performance at the set angle of view and focal length. In the first to third embodiments, mathematical expression 6 can preferably satisfy 0 < CG1 / TTL < 0.1.

[0605]

[0606] [Equation 7]

[0607] 0.3 < ΣCT / TTL < 0.8

[0608] Mathematical expression 7 can set the relationship between the sum (ΣCT) of the center thicknesses of the first to eighth lenses (101-108, 201-208, 301-308) and the TTL, which is the distance (mm) from the center of the first surface (S1) of the first lens (101, 201, 301) to the upper surface of the image sensor (500) on the optical axis (OA). To reduce TTL, a lot of light refraction must occur. To refract a lot of light, the power of the lenses must increase, and to increase the power, the lenses become thicker. When it is less than the lower limit of Mathematical expression 7, the sum of the lens thicknesses becomes small and the refractive power becomes weak. When it is more than the upper limit of Mathematical expression 7, there is a problem that the sum of the thicknesses of the lenses increases excessively, which increases the TTL. In the first to third embodiments, Mathematical expression 7 can preferably satisfy 0.5 < ΣCT / TTL < 0.7.

[0609]

[0610] [Equation 8]

[0611] 0.1 < ΣCG / TTL < 0.5

[0612] Mathematical expression 8 can set the relationship between the sum (ΣCG) of the distances between adjacent lenses among the first to eighth lenses (101-108, 201-208, 301-308) and the TTL, which is the distance (mm) from the center of the first surface (S1) to the upper surface of the image sensor (500) on the optical axis (OA). To reduce TTL, a lot of light refraction must occur. To refract a lot of light, the power of the lenses must increase, and to increase the power, the lenses become thicker. When it is less than the lower limit of Mathematical expression 8, the sum of the thicknesses of the lenses becomes small and the refractive power becomes weaker, becoming weaker than the desired power. When it is more than the upper limit of Mathematical expression 8, there is a problem that the sum of the thicknesses of the lenses increases excessively, which increases the TTL. In the first to third embodiments, Mathematical expression 8 can preferably satisfy 0.2 < ΣCG / TTL < 0.4.

[0613]

[0614] [Equation 9]

[0615] 1 < ΣCT / ΣCG < 3

[0616] In mathematical expression 9, ΣCT is the sum of the central thicknesses of the lenses, and ΣCG is the sum of the spacings between adjacent lenses. When mathematical expression 9 is satisfied, the optical system can have good optical performance at the focal length at the set angle of view, and can reduce the TTL. In the first to third embodiments, mathematical expression 9 can preferably satisfy 1.5 < ΣCT / ΣCG < 2.5.

[0617]

[0618] [Equation 10]

[0619] 25 < ΣAbb / ΣIndex < 30

[0620] In mathematical expression 10, ΣAbb means the sum of the Abbe's numbers of each of the plurality of lenses, and ΣIndex means the sum of the refractive indices at the d-line of each of the plurality of lenses. When mathematical expression 10 is satisfied, the optical system (1000, 1100, 1200) can have improved aberration characteristics and resolution. By setting the sum of the Abbe's numbers and the sum of the refractive indices of the lenses in mathematical expression 10, the optical characteristics can be controlled. In the first to third embodiments, preferably, mathematical expression 10 can satisfy 26 < ΣAbb / ΣIndex < 28.

[0621]

[0622] [Equation 11]

[0623] 1 < ΣCT / ΣET < 2

[0624] In mathematical expression 11, ΣCT is the sum of the central thicknesses of the lenses, and ΣET is the sum of the edge thicknesses, i.e., the ends of the effective areas of the lenses. When mathematical expression 11 is satisfied, the optical system can have good optical performance at the focal length at the set angle of view, and can reduce the TTL. In the first to third embodiments, mathematical expression 11 can preferably satisfy 1 < ΣCT / ΣET < 1.5.

[0625]

[0626] [Equation 12]

[0627] 0.3 < CT1 / ET1 < 0.8

[0628] In mathematical expression 12, CT1 is the center thickness of the first lens (101, 201, 301), and ET1 is the edge thickness of the first lens (101, 201, 301). Through this, factors affecting the angle of view of the optical system can be set, and factors affecting the effective focal length (EFL) can be set. In the first to third embodiments, mathematical expression 12 can preferably satisfy 0.4 < CT1 / ET1 < 0.7.

[0629]

[0630] [Equation 13]

[0631] 1 < CT8 / ET8 < 2.5

[0632] In mathematical expression 13, CT8 is the center thickness of the eighth lens (108, 208, 308), and ET8 is the edge thickness of the eighth lens (108, 208, 308). Through this, factors affecting the angle of view of the optical system can be set, and factors affecting the effective focal length (EFL) can be set. In the first to third embodiments, mathematical expression 13 can preferably satisfy 1.5 < CT8 / ET8 < 2.2.

[0633]

[0634] [Equation 14]

[0635] 1 < GLCa_AVER / PLCa_AVER < 2

[0636] In mathematical expression 14, GLCa_AVER represents the average effective diameter of glass lenses, and PLCa_AVER represents the average effective diameter of plastic lenses. The lens barrel in which the lens unit is arranged has at least one inner barrel within the lens barrel, and at least some of the plastic material lenses included in the lens unit may be arranged in the inner barrel. In the case of plastic material lenses, since the amount of expansion is large at high temperatures, a wider space is required within the lens barrel. In mathematical expression 14, by setting the effective diameter size of the glass lens and the effective diameter size of the plastic lens, the deterioration of optical characteristics due to temperature change can be suppressed, and the optical system (1000, 1100, 1200) can control the incident light and set factors affecting aberration. In the first to third embodiments, mathematical expression 14 can preferably satisfy 1.2 < GLCa_AVER / PLCa_AVER < 1.7.

[0637]

[0638] [Equation 15]

[0639] 1 < CA_L1S1 / CA_L1S2 < 2

[0640] In mathematical expression 15, CA_L1S1 denotes the effective diameter of the first surface (S1) of the first lens (101, 201, 301), and CA_L1S2 denotes the effective diameter of the second surface (S2) of the first lens (101, 201, 301). When mathematical expression 15 is satisfied, the deterioration of optical characteristics due to temperature change can be suppressed, and the optical system (1000, 1100, 1200) can control the incident light and set factors affecting aberration. In the first to third embodiments, mathematical expression 15 can preferably satisfy 1.2 < CA_L1S1 / CA_L1S2 < 1.6.

[0641]

[0642] [Equation 16]

[0643] 1 < CA_L1 / CA_L8 < 2.5

[0644] In mathematical expression 16, CA_L1 denotes the effective diameter of the first lens (101, 201, 301), and CA_L8 denotes the effective diameter of the eighth lens (108, 208, 308). The lens barrel in which the lens unit is arranged has at least one inner barrel within the lens barrel, and at least some of the plastic material lenses included in the lens unit can be arranged in the inner barrel. In the case of a plastic material lens, a large amount of expansion occurs at high temperatures, requiring a wider space within the lens barrel. Therefore, when mathematical expression 16, which sets the relationship between the effective diameter of the first lens (101, 201, 301) made of glass and the effective diameter of the eighth lens (108, 208, 308) made of plastic, is satisfied, the deterioration of optical characteristics due to temperature change can be suppressed, and the optical system (1000, 1100, 1200) can control the incident light and set the factors affecting aberration. In the first to third embodiments, mathematical expression 16 can preferably satisfy 1.5 < CA_L1 / CA_L8 < 2.2.

[0645]

[0646] [Equation 17]

[0647] 3 < CA_L1 / ImgH < 5

[0648] Mathematical expression 17 can set the relationship between the size of the effective diameter (CA_L1) of the first lens (101, 201, 301) and ImgH as 1 / 2 of the maximum diagonal length of the image sensor. When Mathematical expression 17 is satisfied, the TTL suitable for the vehicle optical system is satisfied, and the set angle of view can be satisfied. When it is less than the lower limit of Mathematical expression 17, the effective diameter of the lens arranged in the optical system (1000, 1100, 1200) becomes the largest, which causes a problem in that the TTL becomes long. When it exceeds the upper limit of Mathematical expression 17, there is a problem in that the angle of view becomes excessively larger than the angle of view satisfied by the optical system (1000, 1100, 1200). In the first to third embodiments, Mathematical expression 17 can preferably satisfy 3.5 < CA_L1 / ImgH < 4.8.

[0649]

[0650] [Equation 18]

[0651] 1 < CT_Max / CG_Max < 2

[0652] In mathematical expression 18, CT_Max is the maximum central thickness among the lenses, and CG_Max is the maximum gap between adjacent lenses. When mathematical expression 18 is satisfied, the optical system can have good optical performance at the focal length at the set angle of view, and can reduce the TTL. In the first to third embodiments, mathematical expression 18 can preferably satisfy 1 < CT_Max / CG_Max < 1.7.

[0653]

[0654] [Equation 19]

[0655] 2 < CA_max / CA_min < 3

[0656] In mathematical expression 19, CA_max represents the maximum effective diameter among the object-side and sensor-side surfaces of the lenses, and CA_Min represents the minimum effective diameter among the object-side and sensor-side surfaces of the lenses. When mathematical expression 19 is satisfied, the optical system can set a size for a slim and compact structure while maintaining optical performance. In the first to third embodiments, mathematical expression 19 can preferably satisfy 2.5 < CA_max / CA_min < 3.

[0657]

[0658] [Equation 20]

[0659] 1 < CA_max / CA_Aver < 2

[0660] In mathematical expression 20, CA_max represents the maximum effective diameter among the object-side and sensor-side surfaces of the lenses, and CA_Aver represents the average of the effective diameters of the object-side and sensor-side surfaces of the lenses. When mathematical expression 20 is satisfied, the optical system can set a size for a slim and compact structure while maintaining optical performance. In the first to third embodiments, mathematical expression 20 can preferably satisfy 1.5 < CA_max / CA_Aver < 2.

[0661]

[0662] [Equation 21]

[0663] 0.5 < CA_min / CA_Aver < 1

[0664] In mathematical expression 21, CA_Min represents the minimum effective diameter among the object-side and sensor-side surfaces of the lenses, and CA_Aver represents the average of the effective diameters of the object-side and sensor-side surfaces of the lenses. When mathematical expression 21 is satisfied, the optical system can set a size for a slim and compact structure while maintaining optical performance. In the first to third embodiments, mathematical expression 21 can preferably satisfy 0.6 < CA_min / CA_Aver < 0.8.

[0665]

[0666] [Equation 22]

[0667] 4 < CA_max / ImgH < 5

[0668] In mathematical expression 22, CA_max represents the maximum effective diameter among the object-side and sensor-side surfaces of the lenses, and Imgh represents half of the maximum diagonal length of the image sensor (500). When mathematical expression 22 is satisfied, the optical system can maintain good optical performance and set a size for a slim and compact structure. In the first to third embodiments, mathematical expression 22 can preferably satisfy 4 < CA_max / ImgH < 4.7.

[0669]

[0670] [Equation 23]

[0671] 30 < TTL < 40

[0672] In mathematical expression 23, TTL (Total track length) means the distance (mm) from the center of the first surface (S1) of the first lens (101, 201, 301) to the upper surface of the image sensor (500) on the optical axis (OA). When mathematical expression 23 is satisfied, a suitable vehicle optical system can be provided. In the first to third embodiments, mathematical expression 23 can preferably satisfy 32 < TTL < 38.

[0673]

[0674] [Equation 24]

[0675] 4 < ImgH < 5

[0676] Mathematical expression 24 indicates that ImgH represents half of the maximum diagonal length of the image sensor (500). Mathematical expression 24 can set the diagonal size of the image sensor (500) and provide an optical system having a sensor size for a vehicle. In the first to third embodiments, Mathematical expression 24 can preferably satisfy 4 < ImgH < 4.5.

[0677]

[0678] [Equation 25]

[0679] 0.8 < BFL < 1.5

[0680] In mathematical expression 25, BFL is the optical axis distance from the image sensor (500) to the center of the sensor side of the last lens. When mathematical expression 25 is satisfied, the installation space of the filter (600) and the cover glass can be secured, the assembling of the components can be improved through the gap between the image sensor (500) and the last lens, and the joining reliability can be improved. In the first to third embodiments, mathematical expression 25 can preferably satisfy 0.9 < BFL < 1.2. When the BFL is less than the range of mathematical expression 25, some of the light traveling to the image sensor may not be transmitted to the image sensor, which may cause a decrease in resolution. When the BFL exceeds the range of mathematical expression 25, stray light may be introduced, which may deteriorate the aberration characteristics of the optical system.

[0681]

[0682] [Equation 26]

[0683] 5 < F < 6

[0684] Mathematical expression 26 can set the overall focal length (F) to suit the vehicle optical system. In the first to third embodiments, mathematical expression 26 can satisfy 5 < F < 5.5.

[0685]

[0686] [Equation 27]

[0687] 110 < FOV_H < 150

[0688] In mathematical expression 27, FOV_H represents the horizontal angle of view (Degree) of the optical system (1000, 1100, 1200), and can provide an angle of view suitable for a vehicle optical system. In the first to third embodiments, preferably, 110 < FOV_H < 130 can be satisfied.

[0689]

[0690] [Equation 28]

[0691] 1 < TTL / CA_max < 3

[0692] In mathematical expression 28, CA_max means the largest effective diameter (mm) among the object-side and sensor-side of a plurality of lenses, and TTL (Total track length) means the distance (mm) from the vertex of the first surface (S1) of the first lens (101, 201, 301) to the upper surface of the image sensor (500) on the optical axis (OA). Mathematical expression 28 sets the relationship between the total optical axis length of the optical system and the maximum effective diameter, thereby providing an improved vehicle optical system. In the first to third embodiments, mathematical expression 28 can preferably satisfy 1.5 < TTL / CA_max < 2.5.

[0693]

[0694] [Equation 29]

[0695] 8 < TTL / ImgH < 9

[0696] Mathematical expression 29 indicates that TTL (Total track length) means the distance (mm) from the vertex of the first surface (S1) of the first lens (101, 201, 301) to the upper surface of the image sensor (500) on the optical axis (OA), and ImgH means 1 / 2 of the maximum diagonal length of the image sensor (500). When Mathematical expression 29 is satisfied, the optical system (1000, 1100, 1200) can have TTL for application to the vehicle image sensor (500), thereby providing improved image quality. In the first to third embodiments, Mathematical expression 29 can preferably satisfy 8.2 < TTL / ImgH < 8.7.

[0697]

[0698] [Equation 30]

[0699] 0.1 < BFL / ImgH < 0.5

[0700] Mathematical expression 30 is such that BFL is the optical axis distance from the image sensor (500) to the center of the sensor side of the last lens, and ImgH means half of the maximum diagonal length of the image sensor (500). When Mathematical expression 30 is satisfied, the optical system (1000, 1100, 1200) can secure a BFL (Back focal length) for applying the size of the vehicle image sensor (500), can set the distance between the last lens and the image sensor (500), and can have good optical characteristics at the center and periphery of the field of view (FOV). In the first to third embodiments, Mathematical expression 30 can preferably satisfy 0.1 < BFL / ImgH < 0.3.

[0701]

[0702] [Equation 31]

[0703] 30 < TTL / BFL < 40

[0704] Mathematical expression 31 states that TTL (Total track length) means the distance (mm) from the vertex of the first surface (S1) of the first lens (101, 201, 301) to the upper surface of the image sensor (500) on the optical axis (OA), and BFL means the optical axis distance from the image sensor (500) to the center of the sensor side of the last lens. When mathematical expression 31 is satisfied, the optical system (1000, 1100, 1200) can secure BFL. In the first to third embodiments, mathematical expression 31 can preferably satisfy 32 < TTL / BFL < 37.

[0705]

[0706] [Equation 32]

[0707] 6 < TTL / F < 8

[0708] Mathematical expression 32 indicates that TTL (Total track length) means the distance (mm) from the vertex of the first surface (S1) of the first lens (101, 201, 301) to the upper surface of the image sensor (500) on the optical axis (OA), and F is the effective focal length of the optical system. Accordingly, an optical system for a driver assistance system can be provided. When the optical system (1000, 1100, 1200) according to the embodiment satisfies Mathematical Expression 32, the optical system (1000, 1100, 1200) can have an appropriate focal length in a set TTL range, and provides an optical system that can form an image while maintaining an appropriate focal length even when the temperature changes from low temperature to high temperature. If it is below the lower limit of mathematical expression 32, the refractive power of the lenses needs to be increased, making it difficult to correct spherical aberration or distortion aberration. If it is above the upper limit of mathematical expression 32, the effective diameter or TTL of the lenses may become longer, which may cause a problem of the imaging lens system becoming larger. In the first to third embodiments, mathematical expression 32 may preferably satisfy 6 < TTL / F < 7.

[0709]

[0710] [Equation 33]

[0711] 5 < F / BFL < 7

[0712] Mathematical expression 33 is where F is the effective focal length of the optical system, and BFL means the optical axis distance from the image sensor (500) to the center of the sensor side of the last lens. When Mathematical expression 33 is satisfied, the optical system (1000, 1100, 1200) can have a set angle of view and an appropriate focal length, and an optical system for a vehicle can be provided. In addition, the optical system (1000, 1100, 1200) can minimize the gap between the last lens and the image sensor (500), and thus can have good optical characteristics at the periphery of the field of view (FOV). In the first to third embodiments, Mathematical expression 33 can preferably satisfy 5 < F / BFL < 6.

[0713]

[0714] [Equation 34]

[0715] 1 < F / ImgH < 3

[0716] Mathematical expression 34 indicates that F is the effective focal length of the optical system, and ImgH represents half of the maximum diagonal length of the image sensor (500). Such optical systems (1000, 1100, 1200) may have improved aberration characteristics in the size of the vehicle image sensor (500). In the first to third embodiments, Mathematical expression 34 may preferably satisfy 1 < F / ImgH < 2.

[0717]

[0718] [Equation 35]

[0719]

[0720] In mathematical expression 35, Z can represent Sag, which is the distance from any position on the aspherical surface to the vertex of the aspherical surface along the optical axis. Y can represent the distance from any position on the aspherical surface to the optical axis in the direction perpendicular to the optical axis. c can represent the curvature of the lens, and K can represent the conic constant. In addition, A, B, C, D, E, and F can represent aspheric constants.

[0721]

[0722] The optical system (1000, 1100, 1200) according to the first to third embodiments may satisfy at least one or two or more mathematical expressions from mathematical expressions 1 to 34. In this case, the optical system (1000, 1100, 1200) may have improved optical characteristics. Specifically, when the optical system (1000, 1100, 1200) satisfies at least one or two or more mathematical expressions from mathematical expressions 1 to 34, the optical system (1000, 1100, 1200) may have improved resolution and may improve aberration and distortion characteristics. In addition, the optical system (1000, 1100, 1200) can secure a BFL (Back focal length) for applying a vehicle image sensor (500), compensate for the deterioration of optical characteristics due to temperature change, and minimize the gap between the last lens and the image sensor (500), thereby providing good optical performance in the center and periphery of the field of view (FOV).

[0723]

[0724] Table 10 shows the result values ​​for the mathematical expressions 1 to 34 described above in the optical system (1000, 1100, 1200) of the embodiment. Referring to Table 10, it can be seen that the optical system (1000, 1100, 1200) satisfies at least one, two or more, or three or more of the mathematical expressions 1 to 34. In detail, it can be seen that the optical system (1000, 1100, 1200) according to the embodiment satisfies all of the mathematical expressions 1 to 34. Accordingly, the optical system (1000, 1100, 1200) can have good optical performance and excellent optical characteristics at the center and periphery of the field of view (FOV).

[0725]

[0726] Mathematical expression Example 1 Example 2 Example 3 Example 120 < L1R2 < 5022.19648.26137.54321.7 < n2 < 1.91.82971.82971.8297320 < v2 < 3024.039424.039424.039440 < CG1 / ΣCG < 0.50.29350.19420.273150 < CG1 / ΣCT < 0.50.16280.08430.152460 < CG1 / TTL < 0.30.09440.05380.088970.3 < ΣCT / TTL < 0.80.58020.63850.583180.1 < ΣCG / TTL < 0.50.32170.27720.325491 < ΣCT / ΣCG < 31.80342.30351.79201025 < ΣAbb / ΣIndex < 3027.760127.760127.7601111 < ΣCT / ΣET < 21.01131.03791.0147120.3 < CT1 / ET1 < 0.80.64230.43990.4919131 < CT8 / ET8 < 2.51.64952.18452.1701141 < GLCa_AVER / PLCa_AVER < 21.50571.53411.3890151 < CA_L1S1 / CA_L1S2 < 21.54461.59821.6323161 < CA_L1 / CA_L8 < 2.52.10921.96021.7480173 < CA_L1 / ImgH < 54.31344.57954.0611181 < CT_Max / CG_Max < 21.04601.66551.1093192 < CA_max / CA_min < 32.62112.75612.4276201 < CA_max / CA_Aver < 21.82951.91611.7301210.5 < CA_min / CA_Aver < 10.69800.69520.7127224 < CA_max / ImgH < 54.31344.57954.06112330 < TTL < 4034.100034.100034.1000244 < ImgH < 54.03204.03204.0320250.8 < BFL < 1.51.001.001.00265 < F < 65.105.105.1027110 < FOV_H < 150120.00120.00120.00281 < TTL / CA_max < 31.96071.84672.0825298 < TTL / ImgH < 98.45738.45738.4573300.1 < BFL / ImgH < 0.50.24800.24800.24803130 < TTL / BFL < 4034.1034.1034.10326 < TTL / F < 86.68636.68636.6863335 < F / BFL < 75.105.105.10341 < F / ImgH < 31.26491.26491.2649.

[0727]

[0728] Fig. 34 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. 34, a vehicle camera system according to an embodiment of the invention includes an image generating unit (11), a first information generating unit (12), a second information generating unit (21, 22, 23, 24, 25, 26), and a control unit (14). The image generating unit (11) may include at least one camera module (31) disposed in the vehicle, and may capture images of the front of the vehicle and / or the driver to generate a front image or an interior image of the vehicle. The image generating unit (11) may capture images of the surroundings of the vehicle in one or more directions as well as the front of the vehicle using the camera module (31), to generate an image of the surroundings of the vehicle. Here, the front image and the surrounding images may be digital images, and may include color images, black and white images, infrared images, etc. In addition, the front image and the surrounding images may include still images and moving images. The image generation unit (11) provides the driver image, the front image, and the surrounding image to the control unit (14). Next, the first information generation unit (12) may include at least one radar and / or camera placed in the vehicle, and detects the front of the vehicle to generate first detection information. Specifically, the first information generation unit (12) is placed in the vehicle, and detects the position and speed of vehicles located in front of the vehicle, the presence and position of pedestrians, etc. to generate first detection information.

[0729] By using the first detection information generated by the first information generating unit (12), the distance between the own vehicle and the vehicle in front can be controlled to be maintained at a constant level, and the stability of vehicle operation can be improved in specific preset cases, such as when the driver wants to change the driving lane of the own vehicle or when backing up. The first information generating unit (12) provides the first detection information to the control unit (14). The second information generating unit (21, 22, 23, 24, 25, 26) detects each side of the own vehicle based on the front image generated by the image generating unit (11) and the first detection information generated by the first information generating unit (12), and generates second detection information. Specifically, the second information generating unit (21, 22, 23, 24, 25, 26) may include at least one radar and / or camera disposed in the own vehicle, and may detect the position and speed of vehicles located on the side of the own vehicle or capture images. Here, the second information generation units (21, 22, 23, 24, 25, 26) can be placed at the front two corners, side mirrors, and rear center and rear two corners of the vehicle, respectively.

[0730] At least one information generating unit of these vehicle camera systems may be equipped with an optical system and a camera module having the same as described in the embodiments disclosed above, and may provide or process information acquired through the front, rear, each side or corner area of ​​the vehicle to a user to enable autonomous driving or to protect the vehicle and objects from surrounding safety.

[0731] The optical system of the camera module according to an embodiment of the invention can be installed in multiple units within a vehicle to enhance safety regulations, autonomous driving functions, and convenience. Furthermore, the optical system of the camera module is used as a component for controlling systems such as the Lane Keeping Assistance System (LKAS), Lane Departure Warning System (LDWS), and Driver Monitoring System (DMS). These vehicle camera modules can achieve stable optical performance even under ambient temperature changes and offer competitive pricing, thereby ensuring the reliability of vehicle components.

[0732]

[0733] The features, structures, effects, etc. described in the embodiments above are included in at least one embodiment of the present invention, and are not necessarily limited to just one embodiment. Furthermore, the features, structures, effects, etc. exemplified in each embodiment can be combined or modified in other embodiments by those skilled in the art to which the embodiments pertain. Therefore, the contents related to such combinations and modifications should be construed as falling within the scope of the present invention.

[0734] In addition, although the above description focuses on examples, these are merely examples and do not limit the present invention. Those skilled in the art to which the present invention pertains will appreciate that various modifications and applications not exemplified above are possible without departing from the essential characteristics of the present invention. For example, each component specifically shown in the examples can be modified and implemented. In addition, differences related to such modifications and applications should be interpreted as being included within the scope of the present invention defined in the appended claims.

Claims

1. In order from the object side to the sensor side, First lens; Second lens; A third lens having negative (-) refractive power; A fourth lens having negative (-) refractive power; A fifth lens having positive (+) refractive power; A sixth lens having positive (+) refractive power; seventh lens; and Including an eighth lens having positive (+) refractive power, An optical system in which the second lens among the first to eighth lenses has the greatest refractive index.

2. In paragraph 1, The above second lens is made of glass, The above third lens is an optical system made of plastic.

3. In paragraph 1, The first lens and the seventh lens have negative (-) refractive power, The above second lens is an optical system having positive (+) refractive power.

4. In paragraph 1, An optical system in which the distance between the first lens and the second lens on the optical axis is greater than the distance between the fifth lens and the sixth lens.

5. In paragraph 1, An optical system in which the absolute value of the focal length of the fourth lens among the first to eighth lenses is the largest.

6. In paragraph 1, An optical system in which the distance between the third lens and the fourth lens on the optical axis is greater than the distance between the seventh lens and the eighth lens.

7. In paragraph 1, A first lens group including the first to fifth lenses and a second lens group including the sixth to eighth lenses, An optical system in which the composite focal length of the first lens group is shorter than the composite focal length of the second lens group.

8. In paragraph 1, A first lens group including the first to fifth lenses and a second lens group including the sixth to eighth lenses, An optical system in which the sign of the composite focal length of the first lens group and the sign of the composite focal length of the second lens group are different.

9. In paragraph 1, A first lens group including the first to fifth lenses and a second lens group including the sixth to eighth lenses, An optical system in which the absolute value of the difference between the absolute value of the composite focal length of the first lens group and the absolute value of the focal length of the second lens group satisfies 1 or more and 5 or less.

10. In any one of paragraphs 1 to 9, An optical system that satisfies the following conditions. <Conditional expression> 1.7 < n2 < 1.9 (In the above conditional expression, n2 represents the refractive index of the second lens.)

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