Optical system and camera module

Abstract

An optical system according to an embodiment of the present invention comprises, in order from an object side to a sensor side: a first lens; a second lens having positive (+) refractive power; a third lens; a fourth lens; a fifth lens; and a sixth lens, wherein signs of the refractive powers of the first and second lenses are different from each other, and a sign of the refractive power of any one of the fourth to sixth lenses is different from signs of the refractive powers of the other two 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 having positive (+) refractive power; a third lens; a fourth lens; a fifth lens; and a sixth lens, wherein the signs of the refractive powers of the first and second lenses are different from each other, and the sign of the refractive power of any one of the fourth to sixth lenses is different from the signs of the refractive powers of the other two lenses.

[0011] The absolute value of the focal length of the lens among the fourth to sixth lenses having a different sign of refractive power from the remaining two lenses may be smaller than the absolute value of the focal length of the remaining two lenses.

[0012] The second lens may have a convex meniscus shape toward the sensor, and the third lens may have a biconvex shape.

[0013] Among the absolute values ​​of the focal lengths of the first to sixth lenses, the absolute value of the focal length of the sixth lens may be the largest.

[0014] Among the distances between adjacent lenses on the optical axis, the distance between the first lens and the second lens may be the greatest.

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

[0016] The first and second lenses may be made of glass, and the fourth to sixth lenses may be made of plastic.

[0017] Among the central thicknesses of the first to sixth lenses on the optical axis, the central thickness of the fourth lens may be the smallest.

[0018] Among the refractive indices of the first to sixth lenses, the refractive index of the first lens may be the greatest.

[0019] The following condition can be satisfied. <Condition> 130 < FOV_H < 150 (In the above condition, FOV_H means the horizontal angle of view of the optical system.)

[0020] The following condition can be satisfied. <Condition> 2 < TTL / ImgH < 3 (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 the maximum diagonal length of the image sensor.)

[0021] The following condition can be satisfied. <Condition> 0.8 < |f1| / |f3| < 1.2 (In the above condition, f1 is the focal length of the first lens, and f3 is the focal length of the third lens.)

[0022] The following condition can be satisfied. <Condition> 0.1 < F / TTL < 0.3 (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 F means the total focal length of the optical system.)

[0023] 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 having a negative (-) refractive power; a second lens having a positive (+) refractive power; a third lens having a positive (+) refractive power; a fourth lens; a fifth lens; and a sixth lens, wherein the second lens may have a convex meniscus shape toward the sensor side, and the third lens may have a biconvex shape.

[0024] An aperture is arranged between the third lens and the fourth lens, and the sign of the refractive power of any one of the fourth to sixth lenses may be different from the signs of the refractive powers of the remaining two lenses.

[0025] The signs of the refractive powers of the fourth lens and the fifth lens may be different from each other.

[0026] The absolute value of the focal length of the lens among the fourth to sixth lenses having a different sign of refractive power from the remaining two lenses may be smaller than the absolute value of the focal length of the remaining two lenses.

[0027] Among the distances between adjacent lenses on the optical axis, the distance between the first lens and the second lens may be the greatest.

[0028] The first and second lenses may be made of glass, and the fourth to sixth lenses may be made of plastic.

[0029] Among the central thicknesses of the first to sixth lenses on the optical axis, the central thickness of the fourth lens may be the smallest.

[0030]

[0031] 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 having positive (+) refractive power; a third lens; a fourth lens; a fifth lens; and a sixth lens, wherein the signs of the refractive powers of the first and second lenses are different from each other, and among the absolute values ​​of the focal lengths of the fourth to sixth lenses, the focal length of the sixth lens is the largest.

[0032] The sign of the refractive power of any one of the fourth to sixth lenses may be different from the signs of the refractive powers of the other two lenses.

[0033] The absolute value of the focal length of the lens among the fourth to sixth lenses having a different sign of refractive power from the remaining two lenses may be smaller than the absolute value of the focal length of the remaining two lenses.

[0034] The second lens may have a convex meniscus shape toward the sensor, and the third and fifth lenses may have biconvex shapes.

[0035] Among the absolute values ​​of the focal lengths of the first to sixth lenses, the absolute value of the focal length of the fifth lens may be the smallest.

[0036] Among the distances between adjacent lenses on the optical axis, the distance between the first lens and the second lens may be the greatest.

[0037] The first lens may have negative (-) refractive power, and the third lens may have positive (+) refractive power.

[0038] The first and second lenses may be made of glass, and the fourth to sixth lenses may be made of plastic.

[0039] Among the central thicknesses of the first to sixth lenses on the optical axis, the central thickness of the fourth lens may be the smallest, and the central thickness of the fifth lens may be the largest.

[0040] Among the refractive indices of the first to sixth lenses, the refractive index of the first lens may be the greatest.

[0041] The following condition can be satisfied. <Condition> 130 < FOV_H < 160 (In the above condition, FOV_H means the horizontal angle of view of the optical system.)

[0042] The following condition can be satisfied. <Condition> 2 < TTL / ImgH < 3 (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 the maximum diagonal length of the image sensor.)

[0043] The following condition can be satisfied. <Condition> 0.8 < |f1| / |f3| < 1.2 (In the above condition, f1 is the focal length of the first lens, and f3 is the focal length of the third lens.)

[0044] The following condition can be satisfied. <Condition> 0.1 < F / TTL < 0.3 (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 F means the total focal length of the optical system.)

[0045] In order to solve the above technical problem, the device includes, in order from the object side to the sensor side, a first lens having negative (-) refractive power; a second lens having positive (+) refractive power; a third lens having positive (+) refractive power; a fourth lens having negative (-) refractive power; a fifth lens having positive (+) refractive power; and a sixth lens having negative (-) refractive power, wherein the second lens has a convex meniscus shape toward the sensor side, and the third lens may have a biconvex shape.

[0046] An aperture may be arranged between the third lens and the fourth lens, the first and third lenses may be made of glass, and the fourth to sixth lenses may be made of plastic.

[0047] The absolute value of the focal length of the fifth lens may be smaller than the absolute values ​​of the focal lengths of the fourth and sixth lenses.

[0048] Among the distances between adjacent lenses on the optical axis, the distance between the first lens and the second lens may be the greatest.

[0049] Among the central thicknesses of the first to sixth lenses on the optical axis, the central thickness of the fourth lens may be the smallest, and the central thickness of the fifth lens may be the largest.

[0050] The following condition can be satisfied. <Condition> 2 < TTL / ImgH < 3 (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 the maximum diagonal length of the image sensor.)

[0051] The following condition can be satisfied. <Condition> 0.1 < ΣCG / ΣCT < 0.5 (In the above condition, ΣCT is the sum of the central thicknesses of the first to sixth lenses, and ΣCG is the sum of the spacings between adjacent lenses.)

[0052]

[0053] 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 having a negative (-) refractive power; a third lens; a fourth lens; a fifth lens; and a sixth lens, wherein the signs of the refractive powers of the first and third lenses are different from each other, and the sign of the refractive power of the lens having the smallest absolute value of the focal length among the fourth to sixth lenses is different from the signs of the refractive powers of the remaining two lenses.

[0054] Among the absolute values ​​of the focal lengths of the first to sixth lenses, the absolute value of the focal length of the sixth lens may be the largest.

[0055] The fourth lens may have a convex shape on both sides, and the fifth lens may have a concave shape on both sides.

[0056] Among the distances between adjacent lenses on the optical axis, the distance between the first lens and the second lens may be the greatest.

[0057] The fourth lens may have positive (+) refractive power, the fifth lens may have negative (-) refractive power, and the sixth lens may have positive (+) refractive power.

[0058] The first lens may have negative (-) refractive power, and the third lens may have positive (+) refractive power.

[0059] The first and third lenses may be made of glass, and the fourth to sixth lenses may be made of plastic.

[0060] Among the central thicknesses of the first to sixth lenses on the optical axis, the central thickness of the fifth lens may be the smallest.

[0061] Among the refractive indices of the first to sixth lenses, the refractive index of the third lens may be the greatest.

[0062] The following condition can be satisfied. <Condition> 130 < FOV_H < 150 (In the above condition, FOV_H means the horizontal angle of view of the optical system.)

[0063] The following condition can be satisfied. <Condition> 2 < TTL / ImgH < 3 (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 the maximum diagonal length of the image sensor.)

[0064] The following condition can be satisfied. <Condition> 0.8 < |f1| / |f3| < 1.2 (In the above condition, f1 is the focal length of the first lens, and f3 is the focal length of the third lens.)

[0065] The following condition can be satisfied. <Condition> 0.1 < F / TTL < 0.3 (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 F means the total focal length of the optical system.)

[0066] In order to solve the above technical problem, the optical system according to the present embodiment includes, in order from the object side to the sensor side, a first lens having a negative (-) refractive power; a second lens having a negative (-) refractive power; a third lens having a positive (+) refractive power; a fourth lens; a fifth lens; and a sixth lens, wherein the fourth lens and the fifth lens are cemented lenses, the fourth lens may have a convex shape on both sides, and the fifth lens may have a concave shape on both sides.

[0067] An aperture is arranged between the third lens and the fourth lens, and the sign of the refractive power of any one of the fourth to sixth lenses may be different from the signs of the refractive powers of the remaining two lenses.

[0068] The signs of the refractive powers of the fourth lens and the fifth lens may be different from each other.

[0069] The absolute value of the focal length of the lens among the fourth to sixth lenses having a different sign of refractive power from the remaining two lenses may be smaller than the absolute value of the focal length of the remaining two lenses.

[0070] Among the distances between adjacent lenses on the optical axis, the distance between the first lens and the second lens may be the greatest.

[0071] The first and third lenses may be made of glass, and the fourth to sixth lenses may be made of plastic.

[0072] Among the central thicknesses of the first to sixth lenses on the optical axis, the central thickness of the fifth lens may be the smallest.

[0073] 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.

[0074] 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.

[0075] 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.

[0076] 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.

[0077] 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.

[0078] Fig. 3 is a table showing the Sag values ​​of each lens surface in the optical system according to the first embodiment.

[0079] Fig. 4 is a graph showing data on the diffraction MTF (Modulation Transfer Function) at RGB wavelengths at room temperature of the optical system according to the first embodiment of the present invention.

[0080] FIG. 5 is a graph showing data on the diffraction MTF (Modulation Transfer Function) at RGB wavelengths at low temperatures of the optical system according to the first embodiment of the present invention.

[0081] Fig. 6 is a graph showing data on the diffraction MTF (Modulation Transfer Function) at RGB wavelengths at high temperatures of the optical system according to the first embodiment of the present invention.

[0082] Fig. 7 is a graph showing data on the diffraction MTF (Modulation Transfer Function) at IR wavelength at room temperature of the optical system according to the first embodiment of the present invention.

[0083] Fig. 8 is a graph showing data on the diffraction MTF (Modulation Transfer Function) at low temperatures and at IR wavelengths of the optical system according to the first embodiment of the present invention.

[0084] Fig. 9 is a graph showing data on the diffraction MTF (Modulation Transfer Function) at high temperatures and IR wavelengths of the optical system according to the first embodiment of the present invention.

[0085] Fig. 10 is a graph showing data on aberration characteristics at RGB wavelengths at room temperature of the optical system according to the first embodiment of the present invention.

[0086] Fig. 11 is a side cross-sectional view of an optical system and a camera module having the same according to the second embodiment.

[0087] Fig. 12 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.

[0088] Fig. 13 is a table showing the Sag values ​​of each lens surface in the optical system according to the second embodiment.

[0089] Fig. 14 is a graph showing data on the diffraction MTF (Modulation Transfer Function) at RGB wavelengths at room temperature of the optical system according to the second embodiment.

[0090] Fig. 15 is a graph showing data on the diffraction MTF (Modulation Transfer Function) at RGB wavelengths at low temperatures of the optical system according to the second embodiment of the present invention.

[0091] Fig. 16 is a graph showing data on the diffraction MTF (Modulation Transfer Function) at RGB wavelengths at high temperatures of the optical system according to the second embodiment.

[0092] Fig. 17 is a graph showing data on the diffraction MTF (Modulation Transfer Function) at IR wavelength at room temperature of the optical system according to the second embodiment.

[0093] Fig. 18 is a graph showing data on the diffraction MTF (Modulation Transfer Function) at low temperatures and IR wavelengths of the optical system according to the second embodiment of the present invention.

[0094] Fig. 19 is a graph showing data on the diffraction MTF (Modulation Transfer Function) at high temperatures and IR wavelengths of the optical system according to the second embodiment.

[0095] Fig. 20 is a graph showing data on aberration characteristics at RGB wavelengths at room temperature of an optical system according to the second embodiment.

[0096] Fig. 21 is a side cross-sectional view of an optical system and a camera module having the same according to the third embodiment of the present invention.

[0097] Fig. 22 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.

[0098] Fig. 23 is a table showing the Sag values ​​of each lens surface in the optical system according to the third embodiment.

[0099] Fig. 24 is a graph showing data on the diffraction MTF (Modulation Transfer Function) at room temperature of the optical system according to the third embodiment.

[0100] Fig. 25 is a graph showing data on the diffraction MTF (Modulation Transfer Function) at low temperatures of the optical system according to the third embodiment.

[0101] Fig. 26 is a graph showing data on the diffraction MTF (Modulation Transfer Function) at high temperatures of the optical system according to the third embodiment.

[0102] Fig. 27 is a graph showing data on the aberration characteristics of the optical system according to the third embodiment at room temperature.

[0103] Fig. 28 is a side cross-sectional view of an optical system and a camera module having the same according to the fourth embodiment.

[0104] Fig. 29 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 fourth embodiment.

[0105] Figure 30 is a table showing the Sag values ​​of each lens surface in the optical system according to the fourth embodiment.

[0106] Figure 31 is a graph showing data on the diffraction MTF (Modulation Transfer Function) at room temperature of the optical system according to the fourth embodiment.

[0107] Figure 32 is a graph showing data on the diffraction MTF (Modulation Transfer Function) at low temperatures of the optical system according to the fourth embodiment.

[0108] Figure 33 is a graph showing data on the diffraction MTF (Modulation Transfer Function) at high temperatures of the optical system according to the fourth embodiment.

[0109] Figure 34 is a graph showing data on the aberration characteristics of the optical system according to the fourth embodiment at room temperature.

[0110] Fig. 35 is a side cross-sectional view of an optical system and a camera module having the same according to the fifth embodiment.

[0111] Figure 36 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 fifth embodiment.

[0112] Figure 37 is a table showing the Sag values ​​of each lens surface in the optical system according to the fifth embodiment.

[0113] Fig. 38 is a graph showing data on the diffraction MTF (Modulation Transfer Function) at RGB wavelengths at room temperature of the optical system according to the fifth embodiment of the present invention.

[0114] Fig. 39 is a graph showing data on the diffraction MTF (Modulation Transfer Function) at RGB wavelengths at low temperatures of the optical system according to the fifth embodiment of the present invention.

[0115] Fig. 40 is a graph showing data on the diffraction MTF (Modulation Transfer Function) at RGB wavelengths at high temperatures of the optical system according to the fifth embodiment.

[0116] Figure 41 is a graph showing data on the diffraction MTF (Modulation Transfer Function) at IR wavelength at room temperature of the optical system according to the fifth embodiment of the present invention.

[0117] Fig. 42 is a graph showing data on the diffraction MTF (Modulation Transfer Function) at low temperatures in the IR wavelength of the optical system according to the fifth embodiment of the present invention.

[0118] Fig. 43 is a graph showing data on the diffraction MTF (Modulation Transfer Function) at high temperatures and IR wavelengths of the optical system according to the fifth embodiment of the present invention.

[0119] Fig. 44 is a graph showing data on aberration characteristics at RGB wavelengths at room temperature of the optical system according to the fifth embodiment.

[0120] Fig. 45 is a side cross-sectional view of an optical system and a camera module having the same according to the sixth embodiment.

[0121] Figure 46 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 sixth embodiment.

[0122] Figure 47 is a table showing the Sag values ​​of each lens surface in the optical system according to the sixth embodiment.

[0123] Fig. 48 is an example of a vehicle having an optical system according to an embodiment of the present invention.

[0124] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings.

[0125] 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.

[0126] 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.

[0127] Additionally, the terms used in this embodiment are for the purpose of describing the embodiments and are not intended to limit the present invention.

[0128] 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.

[0129] 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.

[0130] 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.

[0131] 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.

[0132] 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.

[0133] 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.

[0134] 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.

[0135]

[0136] As shown in FIGS. 1, 11, 21, 28, 35, and 45, the optical systems (1000, 1100, 1200, 13000, 1400, 1500) according to the first to sixth embodiments of the present invention may include five or more lenses. The optical systems (1000, 1100, 1200, 13000, 1400, 1500) 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 expensive compared to plastic lenses, and there is a problem that it is difficult to meet the demand for low cost. Therefore, the lenses in the optical system (1000, 1100, 1200, 13000, 1400, 1500) are required to have a mixed configuration of glass lenses and plastic lenses. By adopting these plastic lenses, the optical system (1000, 1100, 1200, 13000, 1400, 1500) can provide light weight and low cost by reducing the thickness of the plastic lenses, and the plastic lenses can provide good correction for various aberrations such as spherical aberration and chromatic aberration. In addition, since the plastic lenses can provide aspherical lenses, the distortion portion in the periphery can be minimized.

[0137] The optical system (1000, 1100, 1200, 13000, 1400, 1500) may include n lenses, where the n-th lens may be the last lens adjacent to the image sensor (700), 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, 6 to 8. The n lenses may have a ratio of glass lenses to plastic lenses in the range of 1:1 to 1:2.5.

[0138] Within the optical system (1000, 1100, 1200, 13000, 1400, 1500), at least one lens closest to the object may be made of glass. Two or fewer lenses closest to the object, for example, one lens, may be made of glass. Since the rate of contraction and expansion of glass lenses due to temperature changes is smaller than that of plastic lenses, the glass lenses may be arranged in an area adjacent to the outside within the lens barrel. In addition, if the lens closest to the object is made of glass, the occurrence of scratches due to contact with external structures can be minimized.

[0139] At least one lens disposed adjacent to the stop within the optical system (1000, 1100, 1200, 13000, 1400, 1500) 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 is a lens with a large influence within the optical system (1000, 1100, 1200, 13000, 1400, 1500), the glass lens may be disposed so that the rate of change in contraction and expansion due to temperature change is small.

[0140] At least one lens closest to the image sensor (700) within the optical system (1000, 1100, 1200, 13000, 1400, 1500) may be made of plastic. For example, at least two lenses closest to the image sensor (700) may be made of plastic, and preferably, at least two lenses adjacent to the image sensor (700) may be made of plastic. That is, since the n-th and n-1-th lenses in the optical system (1000, 1100, 1200, 13000, 1400, 1500) are arranged as plastic lenses, various aberrations can be corrected for the light incident on the image sensor (700).

[0141] Within the optical system (1000, 1100, 1200, 13000, 1400, 1500), plastic lenses can be arranged in series, and glass lenses can be arranged in series. Within the optical system (1000, 1100, 1200, 13000, 1400, 1500), plastic lenses can be arranged between glass lenses. Within the optical system (1000, 1100, 1200, 13000, 1400, 1500), glass lenses can be arranged between plastic lenses.

[0142]

[0143] Each lens (101-106, 201-206, 301-306, 401-406, 501-506, 601-606) can have an object side surface and a sensor side surface. The optical system may have more lenses with aspherical sensor sides and aspherical object sides than the number of plastic lenses. The optical system may 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, 13000, 1400, 1500) has more aspherical lenses than spherical lenses, so it can correct various aberrations.

[0144] Among the lenses of the optical system (1000, 1100, 1200, 13000, 1400, 1500), the lens with the maximum refractive index can be positioned adjacent to the object. The maximum refractive index can be 1.7 or higher. The chromatic dispersion of light incident on the lens with the maximum refractive index can be increased, and the center thickness can be made thinner than the edge thickness. In addition, since the lens with the maximum refractive index is positioned on the object side, it is easy to change the radius of curvature of the second and subsequent lenses, and the center thickness can be increased.

[0145]

[0146] As shown in FIGS. 1, 11, 21, 28, 35 and 45, the optical systems (1000, 1100, 1200, 13000, 1400, 1500) according to the first to sixth 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, 13000, 1400, 1500) may include a first lens group (LG1) and a second lens group (LG2) sequentially arranged along the optical axis (OA) from the object side toward the image sensor (700). The optical system (1000, 1100, 1200, 13000, 1400, 1500) may include n lenses, where 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.

[0147] The optical system (1000, 1100, 1200, 13000, 1400, 1500) 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 of each of the first lens group (LG1) and the second lens group (LG2) may be different. The number of lenses of the first lens group (LG1) may be greater than the number of lenses of the second lens group (LG2). Alternatively, the number of lenses of the first lens group (LG1) and the number of lenses of the second lens group (LG2) may be the same.

[0148] 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.

[0149]

[0150] Within the optical system (1000, 1100, 1200, 13000, 1400, 1500), the lens with the largest effective diameter can be placed closest to the object side. The effective diameter of the lens can increase and decrease from the object side to the sensor side. The effective diameter of the lens can decrease and increase from the object side to the sensor side. Through this, since the light incident on the optical system (1000, 1100, 1200, 13000, 1400, 1500) is structured to gather toward the optical axis and then move away from the optical axis again, the optical system (1000, 1100, 1200, 13000, 1400, 1500) can form a stable optical path.

[0151] 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, 11, 21, 28, 35, and 45, 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.

[0152] Each of the lenses (101-106, 201-206, 301-306, 401-406, 501-506, 601-606) 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.

[0153] The edge thickness (ET1-ET6) of the lenses (101-106, 201-206, 301-306, 401-406, 501-506, 601-606) may refer to the thickness at the end of the effective area. The edge thickness (ET1-ET6) of the lenses (101-106, 201-206, 301-306, 401-406, 501-506, 601-606) may be set based on the lens surface with a larger effective area among the object-side and sensor-side surfaces of each lens.

[0154]

[0155] The optical system (1000, 1100, 1200, 13000, 1400, 1500) may have a TTL / Imgh condition of 2 or more and 3 or less, for example, 2.4 or more and 2.7 or less. TTL (Total track length) is the distance from the center of the object-side surface of the first lens to the optical axis (OA) of the image sensor (700). Imgh is the maximum diagonal length of the image sensor (700). In the first, second, fifth and sixth embodiments, the optical system (1000, 1100, 1200, 13000, 1400, 1500) sets the TTL / Imgh value to 2.4 or more and 2.7 or less, and in the third and fourth embodiments, the optical system (1000, 1100, 1200, 13000, 1400, 1500) sets the TTL / Imgh value to 2 or more and 2.3 or less, thereby providing a vehicle lens optical system. Accordingly, the optical system (1000, 1100, 1200, 13000, 1400, 1500) can provide an image without exaggeration or distortion with respect to the formed image.

[0156] The effective focal length (EFL) within the optical system (1000, 1100, 1200, 13000, 1400, 1500) is set to 2 mm or more and 4 mm or less, and the horizontal field of view (FOV_H) of the first embodiment, the second embodiment, the fifth embodiment, and the sixth embodiment is provided to be 130 or more and 150 or less, and the horizontal field of view (FOV_H) of the first embodiment, the second embodiment, the third embodiment, and the fourth embodiment is provided to be 130 or more and 160 or less, so that the vehicle camera module can be provided as an optical system for monitoring the interior of a vehicle. For example, the optical system and camera module according to the present embodiment can be applied to a camera for an ADAS (Advanced Driving Assistance System) installed inside or outside a vehicle.

[0157]

[0158] The effective diameter of at least one plastic lens within the optical system (1000, 1100, 1200, 13000, 1400, 1500) may be smaller than the length of the image sensor (700). The effective diameter is the diameter or length of the effective area where light is incident. The length of the image sensor (700) 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 (700) within the optical system (1000, 1100, 1200, 13000, 1400, 1500) 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 (700) may be 70% or more and 80% or less.

[0159]

[0160] The lens unit can be a mixture of glass and plastic lenses. The number of plastic lenses can be greater than 60% 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 price competitive. Furthermore, the plastic lenses can correct various aberrations, preventing deterioration of optical performance.

[0161] The embodiment of the invention can reduce the weight of the camera module, provide a lower manufacturing cost, suppress the 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, 13000, 1400, 1500). In addition, the lens surface, such as an aspherical surface or a free-form surface, can be easily polished and processed.

[0162]

[0163] 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 (700). 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, 13000, 1400, 1500) 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, 13000, 1400, 1500).

[0164] The lens unit may include a first lens (101, 201, 301, 401, 501, 601), a second lens (102, 202, 302, 402, 502, 602), a third lens (103, 203, 303, 403, 503, 603), a fourth lens (104, 204, 304, 404, 504, 604), a fifth lens (105, 205, 305, 405, 505, 605), and a sixth lens (106, 206, 306, 406, 506, 606), which are aligned from the object side toward the sensor side along the optical axis.

[0165]

[0166] 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.

[0167] 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, 13000, 1400, 1500) 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.

[0168]

[0169] 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 (700) 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 the maximum diagonal length of the image sensor (700) 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 (700), the plastic lenses may disperse color from the center to the periphery of the image sensor (700).

[0170]

[0171] In the first, second, fifth and sixth embodiments, the average effective diameter of the glass materials may be 5 mm or more, for example, in the range of 5 mm to 7 mm, and in the third and fourth embodiments, the average effective diameter of the glass materials may be 4 mm or more, for example, in the range of 4 mm to 5 mm. In addition, in the first, second, fifth and sixth embodiments, the average effective diameter of the plastic material may be 2.5 mm or more, for example, in the range of 3 mm to 5 mm, and in the third and fourth embodiments, the average effective diameter of the plastic material may be 3 mm or more, for example, in the range of 3.5 mm to 4.5 mm.

[0172] In the first to sixth embodiments, 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.

[0173] Within the lens unit, the minimum effective diameter may be in the range of 1 mm to 3 mm, and the maximum effective diameter may be in the range of 7 mm to 10 mm in the first, second, fifth and sixth embodiments, and in the range of 5 mm to 8 mm in the third and fourth embodiments. 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, 13000, 1400, 1500) can improve resolution and chromatic aberration control characteristics by controlling incident light, and can improve vignetting characteristics of the optical system (1000, 1100, 1200, 13000, 1400, 1500).

[0174]

[0175] The optical system (1000, 1100, 1200, 13000, 1400, 1500) or camera module may include an image sensor (700). The image sensor (700) can detect light and convert it into an electrical signal. The image sensor (700) can detect light that sequentially passes through the lens unit. The image sensor (700) may include an element capable of detecting incident light, such as a charge-coupled device (CCD) or a complementary metal oxide semiconductor (CMOS).

[0176]

[0177] The optical system (1000, 1100, 1200, 13000, 1400, 1500) or camera module may include a filter (800). The filter (800) may be positioned between the last lens and the image sensor (700). The filter (800) may be positioned between the lens closest to the sensor side among the lenses of the lens unit and the image sensor (700). For example, the filter (800) may be positioned between the nth lens and the image sensor (700).

[0178] The cover glass is placed between the filter (800) and the image sensor (700), and protects the upper portion of the image sensor (700) and can prevent the reliability of the image sensor (700) from deteriorating. The cover glass can be removed. The cover glass may be a protective glass.

[0179] The filter (800) may include an infrared filter or an infrared cut-off filter (IR cut-off). The filter (800) may allow light of a set wavelength band to pass through and filter out light of a different wavelength band. When the filter (800) includes an infrared filter, it may block radiant heat emitted from external light from being transmitted to the image sensor (700). In addition, the filter (800) may transmit visible light and reflect infrared light.

[0180] The optical system (1000, 1100, 1200, 13000, 1400, 1500) 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, 13000, 1400, 1500). In the lenses arranged between the object and the aperture, the effective diameter of the lens surface tends to increase from the object side to the aperture. In the lens surfaces arranged between the aperture and the sensor, the effective diameter of the lens surfaces tends to decrease from the aperture to the sensor side. The tendency for the effective diameter of the lens surfaces to increase or decrease does not only mean the case where the effective diameter of the lens surfaces increases or decreases. For example, it also includes the case where the effective diameter of the lens surfaces increases and then decreases as it goes from the aperture to the sensor side.

[0181]

[0182] In the first, second, fifth and sixth embodiments, the sum of the refractive indices of the lenses of the lens unit may be 9 or more, for example, in the range of 10 to 12, 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 200 or more, for example, in the range of 220 to 240, and the average of the Abbe numbers may be 50 or less, for example, in the range of 35 to 45. The sum of the central thicknesses of the entire lens may be 7 mm or more, for example, in the range of 8 mm to 10 mm, and the average of the central thicknesses may be in the range of 1 mm to 3 mm. The sum of the central spacings between the lenses on the optical axis (OA) may be 5 mm or more, for example, in the range of 5 mm to 7 mm, and may be smaller than the sum of the central thicknesses of the lenses. In addition, the average value of the effective diameter of each of the lens surfaces (S1 to S12) of the lens unit may be provided as 3 mm or more, for example, in the range of 3.5 mm to 5 mm.

[0183] In the third and fourth embodiments, the sum of the refractive indices of the lenses of the lens unit may be 9 or more, for example, in the range of 10 to 12, and the average refractive index may be in the range of 1.6 to 1.7. The sum of the Abbe numbers of each of the lenses may be 190 or more, for example, in the range of 200 to 210, and the average Abbe number may be 50 or less, for example, in the range of 30 to 40. The sum of the central thicknesses of the entire lens may be 7 mm or more, for example, in the range of 8 mm to 10 mm, and the average of the central thicknesses may be in the range of 1 mm to 3 mm. The sum of the central spacings between the lenses on the optical axis (OA) may be 2 mm or more, for example, in the range of 3 mm to 4 mm, and may be smaller than the sum of the central thicknesses of the lenses. In addition, the average value of the effective diameter of each lens surface (S1-S12) of the lens unit may be provided as 3 mm or more, for example, in the range of 4 mm to 4.5 mm.

[0184]

[0185] In the optical systems of the first and second embodiments, the F number may be 3 or less, for example, in the range of 2.2 to 2.6.

[0186] The vehicle optical system may have a horizontal field of view (FOV_H) in the Y-axis direction that is greater than 130 degrees and less than 150 degrees, for example, in the range of 135 degrees to 145 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 90 degrees and less than 110 degrees, for example, in the range of 90 degrees to 100 degrees.

[0187] In the optical system of the third and fourth embodiments, the F number may be 3 or less, for example, in the range of 2 to 2.5. The vehicle optical system may have a horizontal field of view (FOV_H) in the Y-axis direction that may be greater than 130 degrees and less than 160 degrees, for example, in the range of 135 degrees to 145 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 80 degrees and less than 100 degrees, for example, in the range of 85 degrees to 95 degrees.

[0188] In the optical system of the fifth and sixth embodiments, the F number may be 3 or less, for example, in the range of 2.2 to 2.6. The vehicle optical system may have a horizontal field of view (FOV_H) in the Y-axis direction that may be greater than 130 degrees and less than 150 degrees, for example, in the range of 135 degrees to 145 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 90 degrees and less than 110 degrees, for example, in the range of 90 degrees to 100 degrees.

[0189]

[0190] In the optical system according to the first to sixth embodiments of the present invention, 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, it is possible to suppress the change in the focus imaging position due to temperature change, and provide a vehicle camera in which various aberrations are well corrected.

[0191] 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).

[0192]

[0193] Since the embodiment is an optical system applied to a vehicle camera, the first lens (101, 201, 301, 401, 501, 601) may be provided as a glass material, even though it is designed using 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, 401, 501, 601) may have a spherical surface and be made of glass.

[0194] 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, 401, 501, 601), and the object-side surface of the first lens (101, 201, 301, 401, 501, 601) 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. In the first embodiment, the second embodiment, the fifth embodiment and the sixth embodiment, the horizontal angle of view may be greater than 130 degrees and less than 150 degrees, for example, in the range of 135 degrees to 145 degrees, and in the third embodiment and the fourth embodiment, the horizontal angle of view may be greater than 130 degrees and less than 160 degrees, for example, in the range of 145 degrees to 155 degrees, for driver monitoring, front / rear photography of the vehicle, or lane detection and detection of debris around the vehicle while the vehicle is being driven.

[0195] This horizontal field of view may be a preset angle for advanced driver assistance systems (ADAS).

[0196] The optical system (1000, 1100, 1200, 13000, 1400, 1500) 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, 13000, 1400, 1500) toward the lenses. Hereinafter, the optical system according to the embodiment will be described in detail.

[0197]

[0198] Hereinafter, the configuration of an optical system according to a first embodiment of the present invention will be described with reference to the drawings.

[0199] An optical system according to the first embodiment includes a lens unit, and the lens unit may include a first lens (101) to a sixth lens (106). The first to sixth lenses (101, 102, 103, 104, 105, 106) 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 sixth lens (106) and a filter (800) and be incident on an image sensor (700).

[0200] 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), an aperture (STOP), a fourth lens (104), a fifth lens (105), and a sixth lens (106).

[0201] 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 sixth lens (106). 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 sixth lens (106). 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 (800), and between the filter (800) and the image sensor (700). In this case, the filter (800) 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 (800), and between the filter (800) and the image sensor (700). In this case, the filter layer may be coated to become a filter.

[0202] 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).

[0203] 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.

[0204] 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.

[0205] The refractive index (n1) of the first lens (101) can satisfy the condition of n1>1.65 or n1>1.71. 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.

[0206]

[0207] The second lens (102) may be arranged second from the object side. The second lens (102) may be arranged fifth 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 plastic material.

[0208] The third surface (S3) on the object side of the second lens (102) may be concave with respect to the optical axis (OA), and the fourth surface (S4) on the sensor side may be convex. The second lens (102) may have a meniscus shape that is convex toward the sensor side. The second lens (102) may have a meniscus shape that is concave toward the object side. Since the second lens (102) functions to gather light into the optical axis through the meniscus shape that is convex toward the sensor side, the effective diameter of the first lens (101) can be reduced, and the optical system can be miniaturized.

[0209] The second lens (102) may be made of plastic and may be aspherical. At least one or both of the third surface (S3) and the fourth surface (S4) may be aspherical. The aspherical coefficients of the third 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.

[0210]

[0211] The third lens (103) may be arranged third from the object side. The third lens (103) may be arranged fourth from the sensor side. The third lens (103) may be arranged between the second lens (102) and the fourth lens (104). The third lens (103) may have positive (+) refractive power on the optical axis (OA). The third lens (103) may include a plastic or glass material. For example, the third lens (103) may be provided as a glass material.

[0212] 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 convex. The third lens (103) may have a shape in which both sides are convex. The third lens (103) may be made of glass and may be spherical.

[0213] The aperture (Stop) may be arranged around the sensor-side sixth surface (S6) of the third lens (103). The aperture (Stop) may be arranged around the object-side eighth surface (S8) of the fourth lens (104). The aperture can reduce the TTL within the field of view range, enabling miniaturization of the optical system. Accordingly, a decrease in the yield by weight of the optical system can be prevented, and production efficiency can be improved. In addition, the optical system can be miniaturized by reducing the TTL within the horizontal field of view (FOV_H) of 130 to 150 degrees.

[0214] A field stop may be arranged between the third lens (103) and the fourth lens (104). The field stop may be formed so that the surface facing the optical axis of the spacer has a protruding shape or a sharp surface. The third lens (103) and the fourth lens (104) are lenses arranged in the central region of the optical system (1000), and may have smaller effective diameters than the first lens (101) arranged on the object side and the sixth lens (106) arranged on the sensor side. Therefore, a field stop may be additionally arranged between the third lens (103) and the fourth lens (104) to prevent ghosting due to diffuse reflection and to prevent the introduction of stray light.

[0215]

[0216] The fourth lens (104) may be arranged fourth from the object side. The fourth lens (104) may be arranged third 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.

[0217] The object-side seventh surface (S7) of the fourth lens (104) with respect to the optical axis may be concave, and the sensor-side eighth surface (S8) may be concave. The fourth lens (104) may have a concave shape on both sides. 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. The aspherical coefficients of the seventh and eighth surfaces (S7, S8) may be provided as S1 and S2 of L4 in FIG. 2. At least one or both of the seventh surface (S7) and the eighth surface (S8) may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0218]

[0219] The fifth lens (105) may be arranged fifth from the object side. The fifth lens (105) may be arranged second 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 with a plastic material.

[0220] 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 a plastic material and may be aspherical. At least one or both of the ninth surface (S9) and the tenth surface (S10) may be aspherical. The aspherical coefficients of the ninth and tenth surfaces (S9, S10) may be provided as S1 and S2 of L5 in FIG. 2. At least one or both of the ninth surface (S9) and the tenth surface (S10) may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0221]

[0222] The fourth lens (104) and the fifth lens (105), which are adjacently arranged lenses, can satisfy the following conditions.

[0223] Condition 1: Refractive index of lens with positive refractive power < refractive index of lens with negative refractive power

[0224] Condition 2: Dispersion of a lens with positive refractive power > Dispersion of a lens with negative refractive power

[0225] Here, among the plastic lenses, the fifth lens (105) has positive refractive power and the fourth lens (104) has negative refractive power, so according to conditions 1 and 2, the refractive index of the fifth lens (105) is smaller than the refractive index of the fourth lens (104), and the dispersion value of the fifth lens (105) is larger than the dispersion value of the fourth lens (104). The chromatic aberration occurring in the plastic lens can be corrected by the plastic lens. In addition, since the fourth lens (104) and the fifth lens (105), which are plastic lenses arranged in succession, satisfy the conditions of a refractive index difference of 0.1 or more and 0.14 or less and an Abbe number difference of 20 or more and 40 or less, the chromatic aberration occurring in the plastic lens can be compensated for by the plastic lens.

[0226] 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 fourth lens (104) and the fifth lens (105).

[0227]

[0228] The sixth lens (106) may be positioned furthest from the object side. The sixth lens (106) may be positioned closest to the image sensor (700). 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 with a plastic material.

[0229] With respect to the optical axis (OA), the eleventh surface (S11) on the object side of the sixth lens (106) may be convex, and the twelfth surface (S12) on the sensor side may be concave. The sixth lens (106) may have a meniscus shape that is convex toward the object side. The sixth lens (106) may have a meniscus shape that is concave toward the sensor side. 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.

[0230] The eleventh surface (S11) of the sixth lens (106) may be provided without a critical point from the optical axis (OA) to the end of the effective area. The twelfth surface (S12) of the sixth lens (106) may include a critical point from the optical axis (OA) to the end of the effective area. When the twelfth surface (S12) has a critical point, it may be located in a range of 65% to 80%, preferably in a range of 70% to 78.5%, of the effective radius (r62) from the optical axis (OA). The critical point of the fifth surface (S5) may be located in a range of 2 mm to 2.3 mm, preferably in a range of 2 mm to 2.2 mm from the optical axis (OA). The twelfth surface (S12) of the sixth lens (106) may have a gull shape in which the SAG value increases toward the end of the effective radius, thereby securing aberration characteristics.

[0231]

[0232] The sixth lens (106) may be a plastic lens closest to the image sensor (700). In addition, by arranging two or more plastic lenses adjacent to the image sensor (700), 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 (700), 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 (105, 106) adjacent to the image sensor (700) 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.

[0233]

[0234] LensSurfaceRadiusThicknessndvdSemiApertureFocal length1S114.4450.7001.73553.854-4.038S22.4041.9752.200 2S3-8.7142.7001.57362.1458.087S4-3.3660.1001.854 3S551.7201.59691.5704.010S6(STOP)-3.7710.6251.147 4S7-13.5800.2501.67190.960-3.153S82.5630.1091.159 5S93.6650.9651.54561.2295.396S10-12.5950.9581.531 6S113.0990.9961.54562.60232.416S123.3460.3022.800 FilterS13Infinity1.0002.885S14Infinity0.5993.007ImageInfinity0.0013.122

[0235]

[0236] 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.

[0237]

[0238] First embodiment First embodiment TTL 13.000 ET 11.6 108 F 2.5 60 ET 22.70 29 F no 2.19 6 ET 31.3000 FOV_V 94.0 ET 40.52 86 FOV_H 140.0 ET 50.7000 FOV (Full Angle) 152.7000 ET 60.4999 EPD 1.166 Img H 6.24 BFL 1.90 2 SD (Stop~L6S2) 3.90 TD (L1S1~L6S2) 11.10

[0239]

[0240] Table 2 shows the characteristics of the optical system according to the first embodiment of the present invention.

[0241] TTL means the optical axis distance from the object-side vertex of the first lens (101) to the image plane, SD means the optical axis distance from the aperture (STOP) to the image-side surface of the sixth lens (106), TD means the optical axis distance from the object-side vertex of the first lens (101) to the image-side surface of the sixth lens (106), F means the total focal length, 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 (700) or the maximum diagonal length, FOV_V means the vertical field of view of the optical system, FOV_H means the horizontal field of view of the optical system, FOV (Full Angle) means the maximum field of view including the margin of the optical system, EPD means the diameter of the entrance pupil (effective aperture), BFL means the optical axis distance from the image-side surface of the sixth lens (106) to the image plane, ET1 to ET6 represent the thickness of the edge area of ​​each lens.

[0242]

[0243] The center thicknesses of the first to sixth lenses (101 to 106) are represented by CT1 to CT6, the edge thicknesses at the ends of the effective areas of each lens are represented by ET1 to ET6, the center gap between two adjacent lenses is represented by CG1 to CG5, and the edge gaps between the edges of each lens are represented by EG1 to EG5. The BFL (Back focal length) is the optical axis distance from the image sensor (700) 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 (700).

[0244] As shown in Fig. 2, among the lenses of the lens unit in the first embodiment, the lens surfaces of the second, fourth, fifth, and sixth lenses (102, 104, 105, and 106) may include aspherical surfaces having a 30th-order aspherical coefficient. For example, the second, fourth, fifth, and sixth lenses (102, 104, 105, and 106) may include lens surfaces having a 30th-order aspherical coefficient. As described above, the aspherical surface having a 30th-order aspherical 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).

[0245] When comparing the absolute values ​​of the curvature radii of each lens, the curvature radii of the first surface (S1) of the first lens (101) on the optical axis (OA) may be the largest among the lenses, and the curvature radii of the second surface (S2) of the first lens (101) may be the smallest among the lenses. The difference between the maximum curvature radii and the minimum curvature radii may be 5 times or more, for example, 6 to 8 times.

[0246] 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.

[0247] 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 greater than the absolute value of the curvature radius of the fourth surface (S4). The absolute value of the curvature radius of the fifth surface (S5) of the third lens (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 less than the absolute value of the curvature radius of the tenth surface (S10). The absolute value of the radius of curvature of the eleventh surface (S11) of the sixth lens (106) may be smaller than the absolute value of the radius of curvature of the twelfth surface (S12).

[0248] The ratio of the radius of curvature of each lens can satisfy the following conditions.

[0249] Condition 1: 5 < |L1R1 / L1R2| < 7

[0250] Condition 2: 2 < |L2R1 / L2R2| < 3

[0251] Condition 3: 1 < |L3R1 / L3R2| < 2

[0252] Condition 4: 4 < |L4R1 / L4R2| < 6

[0253] Condition 5: 1 < |L5R1 / L5R2| < 2

[0254] Condition 6: 0.1 < |L6R1 / L6R2| < 0.5

[0255]

[0256] When describing the central thickness (CT) of the lenses based on the optical axis, the central thickness (CT2) of the second lens (102) is the largest among the lenses, and the central thickness (CT4) of the fourth lens (104) is the smallest among the lenses. The difference between the maximum and minimum central thicknesses among the lenses may be in the range of 1.3 mm or more and 2 mm or less.

[0257] The central thickness of each lens may satisfy any one of the following conditions:

[0258] Condition 1: CT2, CT3, CT5, CT6 > CT1 > CT4

[0259] Condition 2: CT2 > CT1, CT3, CT4, CT5, CT6

[0260] Condition 3: CT2 > CT3 > CT1, CT4, CT5, CT6

[0261] Condition 4: CT1, CT2, CT3, CT5, CT6 > CT4

[0262] Condition 5: CT2, CT3, CT6 > CT5 > CT1, CT4

[0263]

[0264] When describing the center spacing (CG) between the lenses, the center spacing (CG1) between the first lens (101) and the second lens (102) may be maximum, and at least one of the center spacing (CG2) between the second and third lenses (102, 103) and the center spacing (CG4) between the fourth and fifth lenses (104, 105) may be minimum. The difference between the maximum center spacing and the minimum center spacing among the spaced lens spacings may be 1.5 mm or more, for example, in the range of 1.6 mm to 2 mm.

[0265] The center spacing between each lens can satisfy the conditions below.

[0266] Condition 1: CG1 > CG2, CG3, CG4, CG5

[0267] Condition 2: CG1, CG3, CG4, CG5 > CG2

[0268] Condition 3: CG1, CG5 > CG3 > CG2, CG4

[0269] Condition 4: CG1, CG3, CG5 > CG4 > CG2

[0270] Condition 5: CG1 > CG5 > CG2, CG3, CG4

[0271]

[0272] 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).

[0273] The lens having the minimum effective diameter may be a lens arranged between the aperture (STOP) and the sixth lens (106). The lens having the minimum effective diameter may be the fourth lens (104). The lens surface having the minimum effective diameter may be the eighth surface (S8) of the fourth lens (104). 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.

[0274] The effective diameter of each lens can satisfy any one of the conditions below.

[0275] Condition 1: CA_L1 > CA_L2, CA_L3, CA_L4, CA_L5, CA_L6

[0276] Condition 2: CA_L1, CA_L6 > CA_L2 > CA_L3, CA_L4, CA_L5

[0277] Condition 3: CA_L1, CA_L2, CA_L5, CA_L6 > CA_L3 > CA_L4

[0278] Condition 4: CA_L1, CA_L2, CA_L3, CA_L5, CA_L6 > CA_L4

[0279] Condition 5: CA_L1, CA_L2, CA_L6 > CA_L5 > CA_L3, CA_L4

[0280] Condition 6: CA_L1 > CA_L6 > CA_L2, CA_L3, CA_L4, CA_L5

[0281]

[0282] In terms of refractive index, the refractive index of the first lens (101) may be the largest among the lenses and may be greater than 1.6, for example, greater than 1.7. Either or both of the fifth lens (105) and the sixth lens (106) may have the smallest refractive index among the lenses. For example, the refractive index of the fifth lens (105) and the sixth lens (106) 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 (700) 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 (700).

[0283] The refractive index of each lens can satisfy any of the conditions below.

[0284] Condition 1: n1 > n2, n3, n4, n5, n6

[0285] Condition 2: n1, n3, n4 > n2 > n5, n6

[0286] Condition 3: n1, n4 > n3 > n2, n5, n6

[0287] Condition 4: n1 > n4 > n2, n3, n5, n6

[0288] Condition 5: n1, n2, n3, n4 > n5 = n6

[0289]

[0290] Comparing the Abbe numbers, the Abbe number of the third lens (103) is the largest among the lenses and may be 60 or more. The Abbe number of the fourth lens (104) 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 making the Abbe number of the third lens (103) arranged at the center of the optical system (1000) the largest and providing the Abbe number of the fourth lens (104) with a low refractive index adjacent to the image sensor (700) 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 it to the image sensor (700).

[0291] The Abbe number of each lens can satisfy any of the conditions below.

[0292] Condition 1: v3, v5, v6 > v1 > v2, v4

[0293] Condition 2: v1, v3, v5, v6 > v2 > v4

[0294] Condition 3: v3 > v1, v2, v4, v5, v6

[0295] Condition 4: v1, v2, v3, v5, v6 > v4

[0296] Condition 5: v3 > v5 = v6 > v1, v2, v4

[0297]

[0298] The focal lengths (F1, F4) of the first and fourth lenses (101, 104) may have negative (-) signs. The first and fourth lenses (101, 104) may have negative (-) refractive power. The focal lengths (F2, F3, F5, F6) of the second, third, fifth, and sixth lenses (102, 103, 105, and 106) may have positive (+) signs. The second, third, fifth, and sixth lenses (102, 103, 105, and 106) may have positive (+) refractive power.

[0299]

[0300] 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.

[0301] The absolute value of the focal length of each lens can satisfy any of the conditions below.

[0302] Condition 1: |f2|, |f5|, |f6| > |f1| > |f3|, |f4|

[0303] Condition 2: |f6| > |f2| > |f1|, |f3|, |f4|, |f5|

[0304] Condition 3: |f1|, |f2|, |f5|, |f6| > |f3| > |f4|

[0305] Condition 4: |f1|, |f2|, |f3|, |f5|, |f6| > |f4|

[0306] Condition 5: |f2|, |f6| > |f5| > |f1|, |f3|, |f4|

[0307] Condition 6: |f6| > |f1|, |f2|, |f3|, |f4|, |f5|

[0308]

[0309] Any one of the fourth to sixth lenses (104-106) made of a plastic material and arranged adjacent to the sensor side may have a different refractive power from the other two. For example, the fourth lens (104) may have a negative (-) refractive power, and the fifth and sixth lenses (105, 106) may have a positive (+) refractive power. The absolute value of the focal length of one lens among the fourth to sixth lenses (104-106) having a different refractive power from the other two may be smaller than the absolute values ​​of the focal lengths of the other two. The refractive power of one lens among the fourth to sixth lenses (104-106) having a different refractive power from the other two may be larger than the refractive powers of the other two. For example, the absolute value of the focal length of the fourth lens (104) having a negative (-) refractive power may be smaller than the focal lengths of the fifth and sixth lenses (105, 106) having a positive (+) refractive power.

[0310] Since the plastic lens disposed adjacent to the image sensor (700) is sensitive to temperature changes, the composite refractive power of the plastic lens can be designed to be close to 0. In other words, the composite refractive power of the plastic lens disposed adjacent to the image sensor (700) can be reduced. Through this, the refractive power of the plastic lens, which is sensitive to temperature changes, can be offset within the plastic lens, thereby minimizing changes in the performance of the overall optical system, and minimizing the influence of the plastic lens on the optical performance of the overall optical system (1000).

[0311] The ratio of the absolute values ​​of the focal lengths of the glass lenses included in the optical system (1000) can satisfy a value of 0.8 or more and 1.2 or less. For example, the absolute value (|f1| / |f3|) of the ratio of the focal lengths of the first lens (101) and the third lens (103) made of glass can satisfy a value of 0.8 or more and 1.2 or less. In addition, the signs of the focal lengths of the first lens (101) and the third lens (103) made of glass can be different from each other. Through this, the overall refractive power of the optical system (1000) can be greatly affected by the glass lens that is strong against temperature changes.

[0312]

[0313] The thickness (T1) of the first lens (101) may be a difference of at least twice the maximum thickness and the minimum thickness, for example, in the range of 2.1 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 (102) may be a maximum thickness in the range of 1 to 1.3 times the minimum thickness. The second lens (102) may be a minimum in the center thickness (CT2) and the maximum in the edge thickness (ET2). The thickness (T3) of the third lens (103) may be a maximum in the center and a minimum in the edge, and the maximum thickness is a range of 1 to 1.5 times the minimum thickness. The thickness (T4) of the fourth lens (104) may be a minimum in the center and a maximum in the edge, and the maximum thickness is a range of 2 to 2.5 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 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 1.5 to 2 times the minimum thickness.

[0314] 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.

[0315] The thickness of each lens can satisfy any of the conditions below.

[0316] Condition 1: 0.3 < CT1 / ET1 < 0.5, 2 < ET1 / CT1 < 2.5

[0317] Condition 2: 0.5 < CT2 / ET2 < 1, 0.8 < ET2 / CT2 < 1.3

[0318] Condition 3: 1 < CT3 / ET3 < 1.5, 0.5 < ET3 / CT3 < 1

[0319] Condition 4: 0.1 < CT4 / ET4 < 1, 2 < ET4 / CT4 < 2.5

[0320] Condition 5: 1 < CT5 / ET5 < 1.5, 0.5 < ET5 / CT5 < 1

[0321] Condition 6: 1.5 < CT6 / ET6 < 2, 0.3 < ET6 / CT6 < 0.7

[0322] Condition 7: 0.5 < ΣCT / ΣET < 1, 1 < ΣET / ΣCT < 1.5

[0323]

[0324] 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 maximum in the edge and a minimum in the center. The fourth gap (G4) between the fourth and fifth lenses (104, 105) may have a maximum in the center and a minimum 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.

[0325]

[0326] FIGS. 4, 5, and 6 are graphs showing the diffraction MTF (Modulation Transfer Function) of RGB wavelengths at room temperature, low temperature, and high temperature in the optical system of FIG. 1, and are graphs showing the luminance ratio (modulation) according to spatial frequency. As shown in FIGS. 4, 5, and 6, 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. Here, the RGB wavelength may satisfy the visible light range of 435 nm to 650 nm.

[0327] FIGS. 7, 8, and 9 are graphs showing the diffraction MTF (Modulation Transfer Function) of RGB wavelengths at room temperature, low temperature, and high temperature in the optical system of FIG. 1, and are graphs showing the luminance ratio (modulation) according to spatial frequency. As shown in FIGS. 7, 8, and 9, 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. Here, the IR wavelength may satisfy a range of 820 nm to 980 nm or other regions.

[0328] Fig. 10 is a graph showing the aberration characteristics at RGB wavelengths at room temperature in the optical system of Fig. 1. In the aberration graph of Fig. 10, spherical aberration (longitudinal spherical aberration), astigmatic field curves, and distortion are measured from left to right. In Fig. 10, the X-axis may represent the focal length (mm) and the degree of distortion (%), and the Y-axis may represent the height of the image. In addition, the graph for spherical aberration is a graph for light in wavelength bands of about 435 nm, about 486 nm, about 546 nm, about 587 nm, and about 656 nm, and the graphs for astigmatism and distortion are graphs for light in wavelength bands of about 546 nm. In the aberration diagram of Fig. 10, the closer each curve is to the Y-axis, the better the aberration correction function can be interpreted. It can be seen that the optical system (1000) according to the first embodiment has measured values ​​close to the Y-axis in almost all areas. That is, the optical system (1000) according to the first embodiment has improved resolution and can have good optical performance not only in the center of the field of view (FOV) but also in the periphery. 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.

[0329] Table 3 shows changes in optical characteristics such as EFL and field of view (FOV_H) at room temperature, low temperature, and high temperature in the optical system according to the first embodiment. It can be seen that the change rate of the 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 the optical characteristics at low temperature is 5% or less, for example, 3% or less, based on room temperature. In addition, Table 3 compares the MTF focus position shift at RGB wavelength and the MTF focus position shift at IR wavelength in the optical system according to the first embodiment, and the MTF focus position shift at low temperature and high temperature can satisfy a range of 10 um or less based on room temperature, and can satisfy a range of 8 um or less, for example.

[0330]

[0331] Room temperature low temperature high temperature low temperature / room temperature high temperature / room temperature EFL(F) 2.56 2.54 64 2.57 7 7 9 9.46% 100.69% FOV_H 140 140.3 139.6 100.21% 99.71% MTF focus position Shift (RGB wavelength) 0 um - 7 um + 7 um -- MTF focus position Shift (IR wavelength) 0 um - 7 um + 7 um --

[0332]

[0333] 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) and the change rate of horizontal 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.

[0334] 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.

[0335]

[0336] Below, the configuration of an optical system according to a second embodiment of the present invention is described with reference to the drawings.

[0337] An optical system according to a second embodiment includes a lens unit, and the lens unit may include a first lens (201) to a sixth lens (206). The first to sixth lenses (201, 202, 203, 204, 205, 206) 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 sixth lens (206) and a filter (800) and be incident on an image sensor (700).

[0338] 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), an aperture (STOP), a fourth lens (204), a fifth lens (205), and a sixth lens (206).

[0339] 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 sixth lens (206). 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 sixth lens (206). 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 (800), and between the filter (800) and the image sensor (700). In this case, the filter (800) 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 (800), and between the filter (800) and the image sensor (700). In this case, the filter layer may be coated to become a filter.

[0340] 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 (1100).

[0341] 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.

[0342] Due to the refractive characteristics of the first lens (201), the second lens (202) can be further separated from the first lens (201). That is, the center spacing between the first and second lenses (201, 202) can be the largest within the lens unit.

[0343] The refractive index (n1) of the first lens (201) can satisfy the condition of n1>1.65 or n1>1.71. 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.

[0344]

[0345] The second lens (202) may be arranged second from the object side. The second lens (202) may be arranged fifth 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 plastic material.

[0346] The third surface (S3) on the object side of the second lens (202) may be concave with respect to the optical axis (OA), and the fourth surface (S4) on the sensor side may be convex. The second lens (202) may have a meniscus shape that is convex toward the sensor side. The second lens (202) may have a meniscus shape that is concave toward the object side. Since the second lens (202) functions to gather light toward the optical axis through the meniscus shape that is convex toward the sensor side, the effective diameter of the first lens (201) can be reduced, and the optical system can be miniaturized.

[0347] The second lens (202) may be made of plastic and may be aspherical. At least one or both of the third surface (S3) and the fourth surface (S4) may be aspherical. The aspherical coefficients of the third and fourth surfaces (S3, S4) may be provided as S1 and S2 of L2 in FIG. 12. 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.

[0348]

[0349] The third lens (203) may be arranged third from the object side. The third lens (203) may be arranged fourth from the sensor side. The third lens (203) may be arranged between the second lens (202) and the fourth lens (204). The third lens (203) may have positive (+) refractive power on the optical axis (OA). The third lens (203) may include a plastic or glass material. For example, the third lens (203) may be provided as a glass material.

[0350] 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 convex. The third lens (203) may have a shape in which both sides are convex. The third lens (203) may be made of glass and may be spherical.

[0351] The aperture (Stop) may be arranged around the sensor-side sixth surface (S6) of the third lens (203). The aperture (Stop) may be arranged around the object-side eighth surface (S8) of the fourth lens (204). The aperture can reduce the TTL within the field of view range, enabling miniaturization of the optical system. Accordingly, a decrease in the yield by weight of the optical system can be prevented, and production efficiency can be improved. In addition, the optical system can be miniaturized by reducing the TTL within the horizontal field of view (FOV_H) of 130 to 150 degrees.

[0352] A field stop may be arranged between the third lens (203) and the fourth lens (204). The field stop may be formed so that the surface facing the optical axis of the spacer has a protruding shape or a sharp surface. The third lens (203) and the fourth lens (204) are lenses arranged in the central region of the optical system (1100), and may have smaller effective diameters than the first lens (201) arranged on the object side and the sixth lens (206) arranged on the sensor side. Therefore, in order to prevent ghosting due to diffuse reflection and to prevent the introduction of stray light, a field stop may be additionally arranged between the third lens (203) and the fourth lens (204).

[0353]

[0354] The fourth lens (204) may be arranged fourth from the object side. The fourth lens (204) may be arranged third 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.

[0355] 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 in which the object side is convex. The fourth lens (204) may have a meniscus shape in which the sensor side is concave. The fourth lens (204) is 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. 12. 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.

[0356]

[0357] The fifth lens (205) may be arranged as the fifth lens from the object side. The fifth lens (205) may be arranged as the second 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 plastic material.

[0358] 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 a plastic material and may be aspherical. At least one or both of the ninth surface (S9) and the tenth surface (S10) may be aspherical. The aspherical coefficients of the ninth and tenth surfaces (S9, S10) may be provided as S1 and S2 of L5 in FIG. 12. 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.

[0359]

[0360] The fourth lens (204) and the fifth lens (205), which are adjacently arranged lenses, can satisfy the following conditions.

[0361] Condition 1: Refractive index of lens with positive refractive power < refractive index of lens with negative refractive power

[0362] Condition 2: Dispersion of a lens with positive refractive power > Dispersion of a lens with negative refractive power

[0363] Here, among the plastic lenses, the fifth lens (205) has positive refractive power and the fourth lens (204) has negative refractive power, so that according to conditions 1 and 2, the refractive index of the fifth lens (205) is smaller than the refractive index of the fourth lens (204), and the dispersion value of the fifth lens (205) is larger than the dispersion value of the fourth lens (204). The chromatic aberration occurring in the plastic lens can be corrected by the plastic lens. In addition, since the fourth lens (204) and the fifth lens (205), which are plastic lenses arranged in succession, satisfy the conditions of a refractive index difference of 0.1 or more and 0.14 or less and an Abbe number difference of 20 or more and 40 or less, the chromatic aberration occurring in the plastic lens can be compensated for by the plastic lens.

[0364] 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 second embodiment of the present invention, chromatic aberration occurring in a plastic lens can be corrected by using the fourth lens (204) and the fifth lens (205).

[0365]

[0366] The sixth lens (206) may be positioned furthest from the object side. The sixth lens (206) may be positioned closest to the image sensor (700). The sixth lens (206) may have positive (+) or negative (-) refractive power on the optical axis (OA). The sixth lens (206) may have negative (-) refractive power. The sixth lens (206) may include a plastic or glass material. For example, the sixth lens (206) may be provided with a plastic material.

[0367] With respect to the optical axis (OA), the eleventh surface (S11) on the object side of the sixth lens (206) may be convex, and the twelfth surface (S12) on the sensor side may be concave. The sixth lens (206) may have a meniscus shape that is convex toward the object side. The sixth lens (206) may have a meniscus shape that is concave toward the sensor side. 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.

[0368] The eleventh surface (S11) of the sixth lens (206) may be provided without a critical point from the optical axis (OA) to the end of the effective area. The twelfth surface (S12) of the sixth lens (206) may include a critical point from the optical axis (OA) to the end of the effective area. When the twelfth surface (S12) has a critical point, it may be located in a range of 65% to 80%, preferably in a range of 70% to 78.5%, of the effective radius (r62) from the optical axis (OA). The critical point of the fifth surface (S5) may be located in a range of 2 mm to 2.3 mm, preferably in a range of 2 mm to 2.2 mm from the optical axis (OA). The twelfth surface (S12) of the sixth lens (206) may have a gull-shaped shape in which the SAG value increases toward the end of the effective radius, thereby securing aberration characteristics.

[0369]

[0370] The sixth lens (206) may be a plastic lens closest to the image sensor (700). In addition, by arranging two or more plastic lenses adjacent to the image sensor (700), 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 (700), 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 (205, 206) adjacent to the image sensor (700) 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.

[0371]

[0372] LensSurfaceRadiusThicknessndvdSemiApertureFocal length1S112.0041.0471.7354.684.397-4.747S22.5962.0772.369 2S3-6.5562.5001.6719.002.32418.089S4-4.9310.8162.072 3S510.3882.6611.7354.681.4505.073S6(STOP)-5.1580.3751.366 4S735.0920.4161.6719.001.223-3.859S82.4240.0901.444 5S92.8541.5021.5455.711.5643.750S10-5.5911.2511.840 6S112.9800.8151.5455.712.522-116.442S122.5730.5002.801 FilterS13Infinity1.0002.860S14Infinity0.9432.931ImageInfinity0.0013.033

[0373]

[0374] Second embodiment Second embodiment TTL 15.993 ET 11.7460 F 2.628 ET 22.5840 F no 1.996 ET 32.3745 FOV_V 98.8 ET 40.7600 FOV_H 140.0 ET 50.7766 FOV (Full Angle) 152.7 ET 60.7028 EPD 1.31 Img H 6.07 BFL 2.44 SD (Stop~L6S2) 4.45 TD (L1S1~L6S2) 13.55

[0375]

[0376] Tables 4 and 5 show the characteristics of an optical system according to a second embodiment of the present invention. Descriptions of the parameters included in Tables 4 and 5 are omitted as they overlap with those of the first embodiment of the present invention.

[0377]

[0378] The center thicknesses of the first to sixth lenses (201 to 206) are represented by CT1 to CT6, the edge thicknesses at the ends of the effective areas of each lens are represented by ET1 to ET6, the center gap between two adjacent lenses is represented by CG1 to CG5, and the edge gaps between the edges of each lens are represented by EG1 to EG5. The back focal length (BFL) is the optical axis distance from the image sensor (700) 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 (700).

[0379] As shown in Fig. 12, among the lenses of the lens unit in the second embodiment, the lens surfaces of the second, fourth, fifth, and sixth lenses (202, 204, 205, and 206) may include aspherical surfaces having a 30th-order aspherical surface coefficient. For example, the second, fourth, fifth, and sixth lenses (202, 204, 205, and 206) 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 non-zero value) 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).

[0380] When comparing the absolute values ​​of the curvature radii of each lens, the curvature radii of the seventh surface (S7) of the fourth lens (204) on the optical axis (OA) may be the largest among the lenses, and the curvature radii of the eighth surface (S8) of the fourth lens (204) may be the smallest among the lenses. The difference between the maximum curvature radii and the minimum curvature radii may be 15 times or more, for example, 16 times to 20 times.

[0381] 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.

[0382] The absolute value of the curvature radius of the first surface (S1) of the first lens (201) may be greater than the absolute value of the curvature radius of the second surface (S2). The absolute value of the curvature radius of the third surface (S3) of the second lens (202) may be greater than the absolute value of the curvature radius of the fourth surface (S4). The absolute value of the curvature radius of the fifth surface (S5) of the third lens (203) may be greater than the absolute value of the curvature radius of the sixth surface (S6). The absolute value of the curvature radius of the seventh surface (S7) of the fourth lens (204) may be greater than the absolute value of the curvature radius of the eighth surface (S8). The absolute value of the curvature radius of the ninth surface (S9) of the fifth lens (205) may be less than the absolute value of the curvature radius of the tenth surface (S10). The absolute value of the radius of curvature of the eleventh surface (S11) of the sixth lens (206) may be greater than the absolute value of the radius of curvature of the twelfth surface (S12).

[0383] The ratio of the radius of curvature of each lens can satisfy the following conditions.

[0384] Condition 1: 3 < |L1R1 / L1R2| < 5

[0385] Condition 2: 1 < |L2R1 / L2R2| < 3

[0386] Condition 3: 1 < |L3R1 / L3R2| < 3

[0387] Condition 4: 10 < |L4R1 / L4R2| < 15

[0388] Condition 5: 0.1 < |L5R1 / L5R2| < 1

[0389] Condition 6: 1 < |L6R1 / L6R2| < 2

[0390]

[0391] When describing the central thickness (CT) of the lenses based on the optical axis, the central thickness (CT2) of the third lens (203) is the largest among the lenses, and the central thickness (CT4) of the fourth lens (204) 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.

[0392] The central thickness of each lens may satisfy any one of the following conditions:

[0393] Condition 1: CT2, CT3, CT5 > CT1 > CT4, CT6

[0394] Condition 2: CT3 > CT2 > CT1, CT4, CT5, CT6

[0395] Condition 3: CT3 > CT1, CT2, CT4, CT5, CT6

[0396] Condition 4: CT1, CT2, CT3, CT5, CT6 > CT4

[0397] Condition 5: CT2, CT3 > CT5 > CT1, CT4, CT6

[0398]

[0399] When describing the center spacing (CG) between the lenses, the center spacing (CG1) between the first lens (201) and the second lens (202) may be maximum, and at least one of the center spacing (CG2) between the second and third lenses (202, 203) and the center spacing (CG4) between the fourth and fifth lenses (204, 205) may be minimum. The difference between the maximum center spacing and the minimum center spacing among the spaced lens spacings may be 1.5 mm or more, for example, in the range of 1.6 mm to 2 mm.

[0400] The center spacing between each lens can satisfy the conditions below.

[0401] Condition 1: CG1 > CG2, CG3, CG4, CG5

[0402] Condition 2: CG1, CG5 > CG2 > CG3, CG4

[0403] Condition 3: CG1, CG2, CG5 > CG3 > CG4

[0404] Condition 4: CG1, CG2, CG3, CG5 > CG4

[0405] Condition 5: CG1 > CG5 > CG2, CG3, CG4

[0406]

[0407] 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).

[0408] The lens having the minimum effective diameter may be a lens arranged between the aperture (STOP) and the sixth lens (206). The lens having the minimum effective diameter may be the fourth lens (204). The lens surface having the minimum effective diameter may be the eighth surface (S8) of the fourth lens (204). 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.

[0409] The effective diameter of each lens can satisfy any one of the conditions below.

[0410] Condition 1: CA_L1 > CA_L2, CA_L3, CA_L4, CA_L5, CA_L6

[0411] Condition 2: CA_L1, CA_L6 > CA_L2 > CA_L3, CA_L4, CA_L5

[0412] Condition 3: CA_L1, CA_L2, CA_L5, CA_L6 > CA_L3 > CA_L4

[0413] Condition 4: CA_L1, CA_L2, CA_L3, CA_L5, CA_L6 > CA_L4

[0414] Condition 5: CA_L1, CA_L2, CA_L6 > CA_L5 > CA_L3, CA_L4

[0415] Condition 6: CA_L1 > CA_L6 > CA_L2, CA_L3, CA_L4, CA_L5

[0416]

[0417] In terms of refractive index, at least one of the first lens (201) and the third lens (203) may have a maximum refractive index among the lenses and may be greater than 1.7, for example, greater than 1.71. At least one of the fifth lens (205) and the sixth lens (206) may have a minimum refractive index 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 (700) 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 a glass material and the lenses made of a plastic material can be adjusted to guide light to the image sensor (700).

[0418] The refractive index of each lens can satisfy any of the conditions below.

[0419] Condition 1: n1 = n3 > n2, n4, n5, n6

[0420] Condition 2: n1, n3 > n2 = n4 > n5, n6

[0421] Condition 3: n1, n2, n3, n4 > n5 = n6

[0422]

[0423] Comparing the Abbe numbers, the Abbe number of at least one of the fifth lens (205) and the sixth lens (206) is the largest among the lenses, and may be 53 or more. The Abbe number of at least one of the first lens (201) and the third lens (203) 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 third lens (203) arranged at the center of the optical system (1100) to be the largest, and the Abbe number of the fourth lens (204) having a low refractive index adjacent to the image sensor (700) 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 (700).

[0424] The Abbe number of each lens can satisfy any of the conditions below.

[0425] Condition 1: v5, v6 > v1 = v3 > v2, v4

[0426] Condition 2: v1, v3, v5, v6 > v2 = v4

[0427] Condition 3: v5 = v6 > v1, v2, v3, v4

[0428]

[0429] The focal lengths (F1, F4, F6) of the first, fourth, and sixth lenses (201, 204, and 206) may have negative (-) signs. The first, fourth, and sixth lenses (201, 204, and 206) may have negative (-) refractive power. The focal lengths (F2, F3, F5) of the second, third, and fifth lenses (202, 203, and 205) may have positive (+) signs. The second, third, and fifth lenses (202, 203, and 205) may have positive (+) refractive power.

[0430] Additionally, the fourth lens (204) and the fifth lens (205), which are adjacently arranged lenses, can satisfy the following conditions.

[0431] Condition 1: Refractive index of lens with positive refractive power < refractive index of lens with negative refractive power

[0432] Condition 2: Dispersion of a lens with positive refractive power > Dispersion of a lens with negative refractive power

[0433] Here, among the plastic lenses, the fifth lens (205) has positive refractive power and the fourth lens (204) has negative refractive power, so that according to conditions 1 and 2, the refractive index of the fifth lens (205) is smaller than the refractive index of the fourth lens (204), and the dispersion value of the fifth lens (205) is larger than the dispersion value of the fourth lens (204). The chromatic aberration occurring in the plastic lens can be corrected by the plastic lens. In addition, since the fourth lens (204) and the fifth lens (205), which are plastic lenses arranged in succession, satisfy the conditions of a refractive index difference of 0.1 or more and 0.14 or less and an Abbe number difference of 20 or more and 40 or less, the chromatic aberration occurring in the plastic lens can be compensated for by the plastic lens.

[0434] 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 second embodiment of the present invention, chromatic aberration occurring in a plastic lens can be corrected by using the fourth lens (204) and the fifth lens (205).

[0435]

[0436] When comparing the focal lengths in absolute values, the focal length of the sixth lens (206) is the largest among the lenses, and the absolute value of the focal length may be 100 or more and 120 or less. The focal length of the fifth lens (205) is the smallest among the lenses, and the absolute value of the focal length of the fifth lens (205) may be 3 or more and 5 or less.

[0437] The absolute value of the focal length of each lens can satisfy any of the conditions below.

[0438] Condition 1: |f2|, |f3|, |f6| > |f1| > |f4|, |f5|

[0439] Condition 2: |f6| > |f2| > |f1|, |f3|, |f4|, |f5|

[0440] Condition 3: |f2|, |f6| > |f3| > |f1|, |f4|, |f5|

[0441] Condition 4: |f1|, |f2|, |f3|, |f6| > |f4| > |f5|

[0442] Condition 5: |f1|, |f2|, |f3|, |f4|, |f6| > |f5|

[0443] Condition 6: |f6| > |f1|, |f2|, |f3|, |f4|, |f5|

[0444]

[0445] Any one of the fourth to sixth lenses (204-206) made of a plastic material and arranged adjacent to the sensor side may have a different refractive power from the other two. For example, the fourth and sixth lenses (204, 206) may have a negative (-) refractive power, and the fifth lens (206) may have a positive (+) refractive power. The absolute value of the focal length of one lens having a different refractive power from the other two among the fourth to sixth lenses (204-206) may be smaller than the absolute values ​​of the focal lengths of the other two. The refractive power of one lens having a different refractive power from the other two among the fourth to sixth lenses (204-206) may be larger than the refractive powers of the other two. For example, the absolute value of the focal length of the fifth lens (205) having a positive (+) refractive power may be smaller than the focal lengths of the fourth and sixth lenses (204, 206) having a negative (-) refractive power.

[0446] Since the plastic lens disposed adjacent to the image sensor (700) is sensitive to temperature changes, the composite refractive power of the plastic lens can be designed to be close to 0. In other words, the composite refractive power of the plastic lens disposed adjacent to the image sensor (700) can be reduced. Through this, the refractive power of the plastic lens, which is sensitive to temperature changes, can be offset within the plastic lens, thereby minimizing changes in the performance of the overall optical system, and minimizing the influence of the plastic lens on the optical performance of the overall optical system (1100).

[0447] The ratio of the absolute values ​​of the focal lengths of the glass lenses included in the optical system (1100) can satisfy a value of 0.8 or more and 1.2 or less. For example, the absolute value (|f1| / |f3|) of the ratio of the focal lengths of the first lens (201) and the third lens (203) made of glass can satisfy a value of 0.8 or more and 1.2 or less. In addition, the signs of the focal lengths of the first lens (201) and the third lens (203) made of glass can be different from each other. Through this, the overall refractive power of the optical system (1100) can be greatly affected by the glass lens that is strong against temperature changes.

[0448]

[0449] The thickness (T1) of the first lens (201) may be a difference of 1.5 times or more between the maximum thickness and the minimum thickness, for example, in the range of 1.5 to 2 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 the range of 1 to 1.5 times the minimum thickness. The second lens (202) may be a minimum in the center thickness (CT2) and the maximum in the edge thickness (ET2). The thickness (T3) of the third lens (203) may be a maximum in the center and a minimum in the edge, and the maximum thickness is a range of 1 to 1.5 times the minimum thickness. The thickness (T4) of the fourth lens (204) may be a minimum in the center and a maximum in the edge, and the maximum thickness is a range of 1.5 to 2 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 1.5 to 2 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 1 to 1.5 times the minimum thickness.

[0450] 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.

[0451] The thickness of each lens can satisfy any of the conditions below.

[0452] Condition 1: 0.5 < CT1 / ET1 < 1, 1.5 < ET1 / CT1 < 2

[0453] Condition 2: 0.5 < CT2 / ET2 < 1, 1 < ET2 / CT2 < 1.5

[0454] Condition 3: 1 < CT3 / ET3 < 1.5, 0.5 < ET3 / CT3 < 1

[0455] Condition 4: 0.3 < CT4 / ET4 < 0.8, 1.5 < ET4 / CT4 < 2

[0456] Condition 5: 1.5 < CT5 / ET5 < 2, 0.3 < ET5 / CT5 < 0.8

[0457] Condition 6: 1 < CT6 / ET6 < 1.5, 0.5 < ET6 / CT6 < 1

[0458] Condition 7: 0.5 < ΣCT / ΣET < 1, 1 < ΣET / ΣCT < 1.5

[0459]

[0460] 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 maximum in the edge and a minimum in the center. The fourth gap (G4) between the fourth and fifth lenses (204, 205) may have a maximum in the center and a minimum 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.

[0461]

[0462] FIGS. 14, 15, and 16 are graphs showing the diffraction MTF (Modulation Transfer Function) of RGB wavelengths at room temperature, low temperature, and high temperature in the optical system of FIG. 11, and are graphs showing the luminance ratio (modulation) according to spatial frequency. As shown in FIGS. 14, 15, and 16, 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. Here, the RGB wavelength may satisfy the visible light range of 435 nm to 650 nm.

[0463] FIG. 17, FIG. 18, and FIG. 19 are graphs showing the diffraction MTF (Modulation Transfer Function) of RGB wavelengths at room temperature, low temperature, and high temperature in the optical system of FIG. 11, and are graphs showing the luminance ratio (modulation) according to spatial frequency. As shown in FIG. 17, FIG. 18, and FIG. 19, 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. Here, the IR wavelength may satisfy a range of 820 nm to 980 nm or other regions.

[0464] Fig. 20 is a graph showing the aberration characteristics at RGB wavelengths at room temperature in the optical system of Fig. 11. In the aberration graph of Fig. 20, spherical aberration (longitudinal spherical aberration), astigmatic field curves, and distortion are measured from left to right. In Fig. 20, the X-axis may represent the focal length (mm) and the degree of distortion (%), and the Y-axis may represent the height of the image. In addition, the graph for spherical aberration is a graph for light in wavelength bands of about 435 nm, about 486 nm, about 546 nm, about 587 nm, and about 656 nm, and the graphs for astigmatism and distortion are graphs for light in wavelength bands of about 546 nm. In the aberration diagram of Fig. 20, the closer each curve is to the Y-axis, the better the aberration correction function can be interpreted. It can be seen that the optical system (1100) according to the second embodiment has measured values ​​close to the Y-axis in almost all areas. 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 can be 85 degrees or higher, for example, in the range of 85 to 105 degrees.

[0465] Table 6 shows changes in optical characteristics such as EFL and field of view (FOV_H) at room temperature, low temperature, and high temperature in the optical system according to the second embodiment. It can be seen that the change rate of the 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 the optical characteristics at low temperature is 5% or less, for example, 3% or less, based on room temperature. In addition, Table 6 compares the MTF focus position shift at RGB wavelength and the MTF focus position shift at IR wavelength in the optical system according to the second embodiment, and the MTF focus position shift at low temperature and high temperature can satisfy a range of 10 um or less based on room temperature, and can satisfy a range of 8 um or less, for example.

[0466]

[0467] Room temperature low temperature high temperature low temperature / room temperature high temperature / room temperature EFL(F) 2.62752.61342.645499.46%100.7% FOV_H 140.4142.1138.5101.21%98.6% MTF focus position Shift(RGB wavelength) 0um-2um+3um-- MTF focus position Shift(IR wavelength) 0um-7um+7um--

[0468]

[0469] 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) and the change rate of horizontal 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.

[0470] 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.

[0471]

[0472] Below, the configuration of an optical system according to a third embodiment of the present invention is described with reference to the drawings.

[0473] An optical system according to a third embodiment includes a lens unit, and the lens unit may include a first lens (301) to a sixth lens (306). The first to sixth lenses (301, 302, 303, 304, 305, 306) 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 sixth lens (306) and a filter (800) and be incident on an image sensor (700).

[0474] 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), an aperture (STOP), a third lens (303), a fourth lens (304), a fifth lens (305), and a sixth lens (306).

[0475] 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 sixth lens (306). 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 sixth lens (306). 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 (800), and between the filter (800) and the image sensor (700). In this case, the filter (800) 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 (800), and between the filter (800) and the image sensor (700). In this case, the filter layer may be coated to become a filter.

[0476] 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 (1200).

[0477] 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.

[0478] Due to the refractive characteristics of the first lens (301), the second lens (302) can be further separated from the first lens (301). That is, the center spacing between the first and second lenses (301, 302) can be the largest within the lens unit.

[0479] The refractive index (n1) of the first lens (301) can satisfy the condition of n1>1.7 or n1>1.75. 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.

[0480]

[0481] The second lens (302) may be arranged second from the object side. The second lens (302) may be arranged fifth 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 plastic material.

[0482] The third surface (S3) on the object side of the second lens (302) may be concave with respect to the optical axis (OA), and the fourth surface (S4) on the sensor side may be convex. The second lens (302) may have a meniscus shape that is convex toward the sensor side. The second lens (302) may have a meniscus shape that is concave toward the object side. Since the second lens (302) functions to gather light onto the optical axis through the meniscus shape that is convex toward the sensor side, the effective diameter of the first lens (301) can be reduced, and the optical system can be miniaturized.

[0483] The second lens (302) may be made of plastic and may be aspherical. At least one or both of the third surface (S3) and the fourth surface (S4) may be aspherical. The aspherical coefficients of the third and fourth surfaces (S3, S4) may be provided as S1 and S2 of L2 in FIG. 22. 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.

[0484] The aperture (Stop) may be arranged around the sensor-side fourth surface (S4) of the second lens (302). The aperture (Stop) may be arranged around the object-side fifth surface (S5) of the third lens (303). 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 140 to 160 degrees.

[0485]

[0486] The third lens (303) may be arranged third from the object side. The third lens (303) may be arranged fourth 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 positive (+) refractive power on 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 glass material.

[0487] 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 convex. The third lens (303) may have a shape in which both sides are convex. The third lens (303) may be made of glass and may be spherical.

[0488]

[0489] The fourth lens (304) may be arranged fourth from the object side. The fourth lens (304) may be arranged third 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.

[0490] The object-side seventh surface (S7) of the fourth lens (304) with respect to the optical axis may be concave, and the sensor-side eighth surface (S8) may be concave. The fourth lens (304) may have a concave shape on both sides. 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. 22. 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.

[0491]

[0492] The fifth lens (305) may be arranged as the fifth lens from the object side. The fifth lens (305) may be arranged as the second 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 plastic material.

[0493] 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 a plastic material and may be aspherical. At least one or both of the ninth surface (S9) and the tenth surface (S10) may be aspherical. The aspherical coefficients of the ninth and tenth surfaces (S9, S10) may be provided as S1 and S2 of L5 in FIG. 22. 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.

[0494] The fourth lens (304) and the fifth lens (305), which are adjacently arranged lenses, can satisfy the following conditions.

[0495] Condition 1: Refractive index of lens with positive refractive power < refractive index of lens with negative refractive power

[0496] Condition 2: Dispersion of a lens with positive refractive power > Dispersion of a lens with negative refractive power

[0497] Here, among the plastic lenses, the fifth lens (305) has positive refractive power and the fourth lens (304) has negative refractive power, so according to conditions 1 and 2, the refractive index of the fifth lens (305) is smaller than the refractive index of the fourth lens (304), and the dispersion value of the fifth lens (305) is larger than the dispersion value of the fourth lens (304). The chromatic aberration occurring in the plastic lens can be corrected by the plastic lens. In addition, since the fourth lens (304) and the fifth lens (305), which are plastic lenses arranged in succession, satisfy the refractive index difference of 0.1 or more and 0.14 or less and the Abbe number difference of 20 or more and 40 or less, the chromatic aberration occurring in the plastic lens can be compensated for by the plastic lens.

[0498] 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 third embodiment of the present invention, chromatic aberration occurring in a plastic lens can be corrected by using the fourth lens (304) and the fifth lens (305).

[0499]

[0500] The sixth lens (306) may be positioned furthest from the object side. The sixth lens (306) may be positioned closest to the image sensor (700). The sixth lens (306) may have positive (+) or negative (-) refractive power on the optical axis (OA). The sixth lens (306) may have negative (-) refractive power. The sixth lens (306) may include a plastic or glass material. For example, the sixth lens (306) may be provided with a plastic material.

[0501] With respect to the optical axis (OA), the eleventh surface (S11) on the object side of the sixth lens (306) may be convex, and the twelfth surface (S12) on the sensor side may be concave. The sixth lens (306) may have a meniscus shape that is convex toward the object side. The sixth lens (306) may have a meniscus shape that is concave toward the sensor side. 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 of FIG. 22.

[0502] The eleventh surface (S11) of the sixth lens (306) may include a critical point from the optical axis (OA) to the end of the effective area. When the eleventh surface (S11) has a critical point, it may be located in a range of 55% to 70%, preferably 57% to 67%, of the effective radius (r61) from the optical axis (OA). The critical point of the eleventh surface (S11) may be located in a range of 1.3 mm to 1.7 mm, preferably 1.4 mm to 1.6 mm from the optical axis (OA).

[0503] The twelfth surface (S12) of the sixth lens (306) may include a critical point from the optical axis (OA) to the end of the effective area. When the twelfth surface (S12) has a critical point, it may be located in a range of 70% to 85%, preferably 72% to 80%, of the effective radius (r62) from the optical axis (OA). The critical point of the twelfth surface (S12) may be located in a range of 2.1 mm to 2.5 mm, preferably 2.2 mm to 2.4 mm from the optical axis (OA). The twelfth surface (S12) of the sixth lens (306) may have a gull-shaped shape in which the SAG value increases toward the end of the effective radius, thereby securing aberration characteristics.

[0504]

[0505] The sixth lens (306) may be a plastic lens closest to the image sensor (700). In addition, by arranging two or more plastic lenses adjacent to the image sensor (700), 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 (700), 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 (305, 306) adjacent to the image sensor (700) 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.

[0506]

[0507] LensSurfaceRadiusThicknessndvdSemiApertureFocal length1S111.1301.2491.80474.555-4.009S22.3831.9182.187 2S3-11.4552.2901.67191.96610.627S4-4.7820.4391.419 3S5(STOP)9.6771.5721.77500.8673.747S6-3.8640.2451.307 4S7-18.8730.4001.67191.398-3.648S82.8720.2531.711 5S94.6802.5631.54562.0093.019S10-2.0080.1752.372 6S114.1870.9081.67192.450-6.866S122.0120.5153.007 FilterS13Infinity0.8003.051S14Infinity0.6913.158ImageInfinity0.0013.304

[0508]

[0509] Third embodiment Third embodiment TTL 14.01 9ET 11.7095 F2.138 ET 22.3357 Fno2.398 ET 31.3066 FOV_V89.6 ET 40.8785 FOV_H 150.3 ET 50.8119 FOV_D 179.2 ET 61.4207 EPD 0.892 Img H 6.24 BFL 2.007 SD(Stop~L6S2) 4.54 TD(L1S1~L6S2) 12.01

[0510]

[0511] Tables 7 and 8 show the characteristics of an optical system according to a third embodiment of the present invention. Descriptions of the parameters included in Tables 7 and 8 are omitted as they overlap with those of the first embodiment of the present invention.

[0512] The center thicknesses of the first to sixth lenses (301 to 306) are represented by CT1 to CT6, the edge thicknesses at the ends of the effective areas of each lens are represented by ET1 to ET6, the center gap between two adjacent lenses is represented by CG1 to CG5, and the edge gaps between the edges of each lens are represented by EG1 to EG5. The BFL (Back focal length) is the optical axis distance from the image sensor (700) 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 (700).

[0513] As shown in Fig. 22, among the lenses of the lens unit in the third embodiment, the lens surfaces of the second, fourth, fifth, and sixth lenses (302, 304, 305, and 306) may include aspherical surfaces having a 30th-order aspherical surface coefficient. For example, the second, fourth, fifth, and sixth lenses (302, 304, 305, and 306) 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 non-zero value) 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).

[0514] When comparing the absolute values ​​of the curvature radii of each lens, the curvature radii of the seventh surface (S7) of the fourth lens (304) on the optical axis (OA) may be the largest among the lenses, and the curvature radii of the tenth surface (S10) of the fifth lens (305) may be the smallest among the lenses. The difference between the maximum curvature radii and the minimum curvature radii may be 5 times or more, for example, 6 to 10 times.

[0515] 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.

[0516] 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 greater than the absolute value of the curvature radius of the fourth surface (S4). The absolute value of the curvature radius of the fifth surface (S5) of the third lens (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 radius of curvature of the eleventh surface (S11) of the sixth lens (306) may be greater than the absolute value of the radius of curvature of the twelfth surface (S12).

[0517] The ratio of the radius of curvature of each lens can satisfy the following conditions.

[0518] Condition 1: 3 < |L1R1 / L1R2| < 5

[0519] Condition 2: 2 < |L2R1 / L2R2| < 3

[0520] Condition 3: 2 < |L3R1 / L3R2| < 3

[0521] Condition 4: 5 < |L4R1 / L4R2| < 7

[0522] Condition 5: 2 < |L5R1 / L5R2| < 4

[0523] Condition 6: 1 < |L6R1 / L6R2| < 3

[0524]

[0525] 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 (CT4) of the fourth lens (304) 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 mm or less.

[0526] The central thickness of each lens may satisfy any one of the following conditions:

[0527] Condition 1: CT2, CT3, CT5 > CT1 > CT4, CT6

[0528] Condition 2: CT5 > CT2 > CT1, CT3, CT4, CT6

[0529] Condition 3: CT2, CT5 > CT3 > CT1, CT4, CT6

[0530] Condition 4: CT1, CT2, CT3, CT5, CT6 > CT4

[0531] Condition 5: CT5 > CT1, CT2, CT3, CT4, CT6

[0532] Condition 6: CT1, CT2, CT3, CT5 > CT6 > CT4

[0533]

[0534] 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 spacings (CG5) between the fifth and sixth lenses (305, 306) may be minimum. The difference between the maximum center spacing and the minimum center spacing among the spaced lens spacings may be 1.5 mm or more, for example, in the range of 1.6 mm to 2 mm.

[0535] The center spacing between each lens can satisfy the conditions below.

[0536] Condition 1: CG1 > CG2, CG3, CG4, CG5

[0537] Condition 2: CG1 > CG2 > CG3, CG4, CG5

[0538] Condition 3: CG1, CG2, CG4 > CG3 > CG5

[0539] Condition 4: CG1, CG2 > CG4 > CG3, CG5

[0540] Condition 5: CG1, CG2, CG3, CG4 > CG5

[0541]

[0542] 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).

[0543] The lens having the minimum effective diameter may be a lens arranged between the aperture (STOP) and the sixth lens (306). The lens having the minimum effective diameter may be the third lens (303). The lens surface having the minimum effective diameter may be the fifth surface (S5) of the third lens (303). 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.

[0544] The effective diameter of each lens can satisfy any one of the conditions below.

[0545] Condition 1: CA_L1 > CA_L2, CA_L3, CA_L4, CA_L5, CA_L6

[0546] Condition 2: CA_L1, CA_L5, CA_L6 > CA_L2 > CA_L3, CA_L4

[0547] Condition 3: CA_L1, CA_L2, CA_L4, CA_L5, CA_L6 > CA_L3

[0548] Condition 4: CA_L1, CA_L2, CA_L5, CA_L6 > CA_L4 > CA_L3

[0549] Condition 5: CA_L1, CA_L6 > CA_L5 > CA_L2, CA_L3, CA_L4

[0550] Condition 6: CA_L1 > CA_L6 > CA_L2, CA_L3, CA_L4, CA_L5

[0551]

[0552] In terms of refractive index, the refractive index of the first lens (301) is the largest among the lenses and may be greater than 1.7, for example, greater than 1.75. The refractive index of the fifth lens (305) is 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 (700) 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 (700).

[0553] The refractive index of each lens can satisfy any of the conditions below.

[0554] Condition 1: n1 > n2, n3, n4, n5, n6

[0555] Condition 2: n1, n3 > n2 = n4 = n6 > n5

[0556] Condition 3: n1 > n3 > n2, n4, n5, n6

[0557] Condition 4: n1, n2, n3, n4, n6 > n5

[0558]

[0559] Comparing the Abbe numbers, the Abbe number of the fifth lens (305) is the largest among the lenses and may be 45 or more. The Abbe number of at least one of the second lens (302), the fourth lens (304), and the sixth lens (306) 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 30 or more. By providing the largest Abbe number of the third lens (303) arranged at the center of the optical system (1200) and the smallest Abbe number of the sixth lens (306) having a low refractive index adjacent to the image sensor (700), 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 (700).

[0560] The Abbe number of each lens can satisfy any of the conditions below.

[0561] Condition 1: v3, v5 > v1 > v2, v4, v6

[0562] Condition 2: v1, v3, v5 > v2 = v4 = v6

[0563] Condition 3: v5 > v3 > v1, v2, v4, v6

[0564] Condition 4: v5 > v1, v2, v3, v4, v6

[0565]

[0566] The focal lengths (F1, F4, F6) of the first, fourth, and sixth lenses (301, 304, and 306) may have negative (-) signs. The first, fourth, and sixth lenses (301, 304, and 306) may have negative (-) refractive power. The focal lengths (F2, F3, F5) of the second, third, and fifth lenses (302, 303, and 305) may have positive (+) signs. The second, third, and fifth lenses (302, 303, and 305) may have positive (+) refractive power.

[0567]

[0568] When comparing the focal lengths in absolute values, the focal length of the second lens (302) is the largest among the lenses, and may be 8 or more and 12 or less. The focal length of the fifth lens (305) is the smallest among the lenses, and the absolute value of the focal length of the fifth lens (305) may be 2 or more and 4 or less.

[0569] The absolute value of the focal length of each lens can satisfy any of the conditions below.

[0570] Condition 1: |f2|, |f6| > |f1| > |f3|, |f4|, |f5|

[0571] Condition 2: |f2| > |f1|, |f3|, |f4|, |f5|, |f6|

[0572] Condition 3: |f1|, |f2|, |f6| > |f3| > |f4|, |f5|

[0573] Condition 4: |f1|, |f2|, |f3|, |f6| > |f4| > |f5|

[0574] Condition 5: |f1|, |f2|, |f3|, |f4|, |f6| > |f5|

[0575] Condition 6: |f2| > |f6| > |f1|, |f3|, |f4|, |f5|

[0576]

[0577] Any one of the fourth to sixth lenses (304-306) made of a plastic material and arranged adjacent to the sensor side may have a different refractive power from the other two. For example, the fourth and sixth lenses (304, 306) may have a negative (-) refractive power, and the fifth lens (305) may have a positive (+) refractive power. The absolute value of the focal length of one lens among the fourth to sixth lenses (304-306) having a different refractive power from the other two may be smaller than the absolute values ​​of the focal lengths of the other two. The refractive power of one lens among the fourth to sixth lenses (304-306) having a different refractive power from the other two may be larger than the refractive powers of the other two. For example, the absolute value of the focal length of the fifth lens (305) having a positive (+) refractive power may be smaller than the absolute values ​​of the focal lengths of the fourth and sixth lenses (304, 306) having a negative (-) refractive power.

[0578] Since the plastic lens disposed adjacent to the image sensor (700) is sensitive to temperature changes, the composite refractive power of the plastic lens can be designed to be close to 0. In other words, the composite refractive power of the plastic lens disposed adjacent to the image sensor (700) can be reduced. Through this, the refractive power of the plastic lens, which is sensitive to temperature changes, can be offset within the plastic lens, thereby minimizing changes in the performance of the overall optical system, and minimizing the influence of the plastic lens on the optical performance of the overall optical system (1200).

[0579] The ratio of the absolute values ​​of the focal lengths of the glass lenses included in the optical system (1200) can satisfy a value of 0.8 or more and 1.2 or less. For example, the absolute value (|f1| / |f3|) of the ratio of the focal lengths of the first lens (301) and the third lens (303) made of glass can satisfy a value of 0.8 or more and 1.2 or less. In addition, the signs of the focal lengths of the first lens (301) and the third lens (303) made of glass can be different from each other. Through this, the overall refractive power of the optical system (1200) can be greatly affected by the glass lens that is strong against temperature changes.

[0580]

[0581] The thickness (T1) of the first lens (301) may be a difference of at least 1 time between the maximum thickness and the minimum thickness, for example, 1.2 to 1.5 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 1.3 times the minimum thickness. The second lens (302) may be a minimum in the center thickness (CT2) and the maximum in the edge thickness (ET2). The thickness (T3) of the third lens (303) may be a maximum in the center and a minimum in the edge, and the maximum thickness is a range of 1 to 1.5 times the minimum thickness. The thickness (T4) of the fourth lens (304) may be a minimum in the center and a maximum in the edge, and the maximum thickness is a range of 2 to 2.5 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 3 to 3.5 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 1 to 2 times the minimum thickness.

[0582] 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.

[0583] The thickness of each lens can satisfy any of the conditions below.

[0584] Condition 1: 0.5 < CT1 / ET1 < 1, 1 < ET1 / CT1 < 1.5

[0585] Condition 2: 0.5 < CT2 / ET2 < 1, 0.8 < ET2 / CT2 < 1.3

[0586] Condition 3: 1 < CT3 / ET3 < 1.5, 0.5 < ET3 / CT3 < 1

[0587] Condition 4: 0.1 < CT4 / ET4 < 1, 2 < ET4 / CT4 < 2.5

[0588] Condition 5: 3 < CT5 / ET5 < 3.5, 0.1 < ET5 / CT5 < 0.5

[0589] Condition 6: 0.5 < CT6 / ET6 < 1, 1 < ET6 / CT6 < 2

[0590] Condition 7: 0.8 < ΣCT / ΣET < 1.2, 0.5 < ΣET / ΣCT < 1

[0591]

[0592] 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 maximum in the edge and a minimum in the center. The fourth gap (G4) between the fourth and fifth lenses (304, 305) may have a maximum in the center and a minimum 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.

[0593]

[0594] FIGS. 24, 25, and 26 are graphs showing the diffraction MTF (Modulation Transfer Function) at room temperature, low temperature, and high temperature in the optical system of FIG. 21, and are graphs showing the modulation ratio according to spatial frequency. As shown in FIGS. 24, 25, and 26, 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.

[0595] Fig. 27 is a graph showing the aberration characteristics at RGB wavelengths at room temperature in the optical system of Fig. 21. In the aberration graph of Fig. 27, spherical aberration (longitudinal spherical aberration), astigmatic field curves, and distortion are measured from left to right. In Fig. 27, the X-axis may represent the focal length (mm) and the degree of distortion (%), and the Y-axis may represent the height of the image. In addition, the graph for spherical aberration is a graph for light in wavelength bands of about 435 nm, about 486 nm, about 546 nm, about 587 nm, and about 656 nm, and the graphs for astigmatism and distortion are graphs for light in wavelength bands of about 546 nm. In the aberration diagram of Fig. 27, the closer each curve is to the Y-axis, the better the aberration correction function can be interpreted. It can be seen that the optical system (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 can be 85 degrees or higher, for example, in the range of 85 degrees to 305 degrees.

[0596] Table 9 shows changes in optical characteristics such as EFL and field of view (FOV_H) at room temperature, low temperature, and high temperature in the optical system according to the third embodiment. It can be seen that the change rate of the 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 the optical characteristics at low temperature is 5% or less, for example, 3% or less, based on room temperature. In addition, Table 9 compares the MTF focus position shift in the optical system according to the third embodiment, and the MTF focus position shift at low and high temperatures can satisfy a range of 10 um or less based on room temperature, and can satisfy a range of 5 um or less, for example.

[0597]

[0598] Room temperature low temperature high temperature low temperature / room temperature high temperature / room temperature EFL(F) 2.13842.12672.152199.45%100.64%FOV_H150.4150.9149.7100.33%99.53%MTF focus position Shift0um-4um+5um--

[0599] 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) and the change rate of horizontal 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.

[0600] 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.

[0601]

[0602] Below, the configuration of an optical system according to a fourth embodiment of the present invention is described with reference to the drawings.

[0603] An optical system according to the fourth embodiment includes a lens unit, and the lens unit may include a first lens (401) to a sixth lens (406). The first to sixth lenses (401, 402, 403, 404, 405, 406) may be sequentially arranged along an optical axis (OA). Light corresponding to information about an object may pass through the first lens (401) to the sixth lens (406) and a filter (800) and be incident on an image sensor (700).

[0604] The lens section may be arranged in order from the object side to the image side, including a first lens (401), a second lens (402), an aperture (STOP), a third lens (403), a fourth lens (404), a fifth lens (405), and a sixth lens (406).

[0605] In another embodiment, one or more of another lens, a flat plate, and an optical member may be added between the first lens (401) to the sixth lens (406). In addition, one or more of another lens, a flat plate, and an optical member may be added in front of the first lens (401) or behind the sixth lens (406). 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 (800), and between the filter (800) and the image sensor (700). In this case, the filter (800) 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 (800), and between the filter (800) and the image sensor (700). In this case, the filter layer may be coated to become a filter.

[0606] The first lens (401) may be arranged closest to the object side. The first lens (401) may be arranged farthest from the sensor side. The first lens (401) may have negative (-) refractive power on the optical axis (OA). The first lens (401) may include a plastic material or a glass material, and may be made of glass, for example. The first lens (401) 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 (1300).

[0607] The first surface (S1) on the object side of the first lens (401) with respect to the optical axis may be convex, and the second surface (S2) on the sensor side may be concave. The first lens (401) may have a meniscus shape that is convex toward the object side. The first lens (401) 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.

[0608] Due to the refractive characteristics of the first lens (401), the second lens (402) can be further separated from the first lens (401). That is, the center spacing between the first and second lenses (401, 402) can be the largest within the lens unit.

[0609] The refractive index (n1) of the first lens (401) can satisfy the condition of n1>1.7 or n1>1.75. The radius of curvature of the first and second lenses (401, 402) can be increased, and lens manufacturing can be facilitated. If the refractive index (n1) of the first lens (401) 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 (401, 402). In this case, lens manufacturing is not easy, the lens defect rate increases, and it may cause a decrease in yield.

[0610]

[0611] The second lens (402) may be arranged second from the object side. The second lens (402) may be arranged fifth from the sensor side. The second lens (402) may be arranged between the first lens (401) and the third lens (403). The second lens (402) may have positive (+) refractive power on the optical axis (OA). The second lens (402) may include a plastic or glass material. For example, the second lens (402) may be provided as a plastic material.

[0612] The third surface (S3) on the object side of the second lens (402) may be concave with respect to the optical axis (OA), and the fourth surface (S4) on the sensor side may be convex. The second lens (402) may have a meniscus shape that is convex toward the sensor side. The second lens (402) may have a meniscus shape that is concave toward the object side. The second lens (402) may be made of a plastic 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. 32. 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.

[0613] The aperture (Stop) may be arranged around the sensor-side fourth surface (S4) of the second lens (402). The aperture (Stop) may be arranged around the object-side fifth surface (S5) of the third lens (403). 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 140 to 160 degrees.

[0614]

[0615] The third lens (403) may be arranged third from the object side. The third lens (403) may be arranged fourth from the sensor side. The third lens (403) may be arranged between the second lens (402) and the fourth lens (404). The third lens (403) may have positive (+) refractive power on the optical axis (OA). The third lens (403) may include a plastic or glass material. For example, the third lens (403) may be provided as a glass material.

[0616] The fifth surface (S5) on the object side of the third lens (403) with respect to the optical axis may be convex, and the sixth surface (S6) on the sensor side may be convex. The third lens (403) may have a shape in which both sides are convex. The third lens (403) may be made of glass and may be spherical.

[0617]

[0618] The fourth lens (404) may be arranged fourth from the object side. The fourth lens (404) may be arranged third from the sensor side. The fourth lens (404) may be arranged between the third lens (403) and the fifth lens (405). The fourth lens (404) may have positive (+) or negative (-) refractive power on the optical axis (OA). The fourth lens (404) may have negative (-) refractive power. The fourth lens (404) may include a plastic or glass material. For example, the fourth lens (404) may be provided as a plastic material.

[0619] The object-side seventh surface (S7) of the fourth lens (404) with respect to the optical axis may be concave, and the sensor-side eighth surface (S8) may be concave. The fourth lens (404) may have a concave shape on both sides. The fourth lens (404) 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. 32. 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.

[0620]

[0621] The fifth lens (405) may be arranged as the fifth lens from the object side. The fifth lens (405) may be arranged as the second lens from the sensor side. The fifth lens (405) may be arranged between the fourth lens (404) and the sixth lens (406). The fifth lens (405) may have positive (+) or negative (-) refractive power on the optical axis (OA). The fifth lens (405) may have positive (+) refractive power. The fifth lens (405) may include a plastic or glass material. For example, the fifth lens (405) may be provided as a plastic material.

[0622] With respect to the optical axis (OA), the ninth surface (S9) on the object side of the fifth lens (405) may be convex, and the tenth surface (S10) on the sensor side may be convex. The fifth lens (405) may have a shape in which both sides are convex. The fifth lens (405) may be made of a plastic material and may be aspherical. At least one or both of the ninth surface (S9) and the tenth surface (S10) may be aspherical. The aspherical coefficients of the ninth and tenth surfaces (S9, S10) may be provided as S1 and S2 of L5 in FIG. 32. 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.

[0623] The fourth lens (404) and the fifth lens (405), which are adjacently arranged lenses, can satisfy the following conditions.

[0624] Condition 1: Refractive index of lens with positive refractive power < refractive index of lens with negative refractive power

[0625] Condition 2: Dispersion of a lens with positive refractive power > Dispersion of a lens with negative refractive power

[0626] Here, among the plastic lenses, the fifth lens (405) has positive refractive power and the fourth lens (404) has negative refractive power, so according to conditions 1 and 2, the refractive index of the fifth lens (405) is smaller than the refractive index of the fourth lens (404), and the dispersion value of the fifth lens (405) is larger than the dispersion value of the fourth lens (404). The chromatic aberration occurring in the plastic lens can be corrected by the plastic lens. In addition, since the fourth lens (404) and the fifth lens (405), which are plastic lenses arranged in succession, satisfy the refractive index difference of 0.1 to 0.14 and the Abbe number difference of 20 to 40, the chromatic aberration occurring in the plastic lens can be compensated for by the plastic lens.

[0627] 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 first embodiment of the present invention, chromatic aberration occurring in a plastic lens can be corrected by using the fourth lens (404) and the fifth lens (405).

[0628]

[0629] The sixth lens (406) may be positioned furthest from the object side. The sixth lens (406) may be positioned closest to the image sensor (700). The sixth lens (406) may have positive (+) or negative (-) refractive power on the optical axis (OA). The sixth lens (406) may have negative (-) refractive power. The sixth lens (406) may include a plastic or glass material. For example, the sixth lens (406) may be provided with a plastic material.

[0630] With respect to the optical axis (OA), the eleventh surface (S11) on the object side of the sixth lens (406) may be convex, and the twelfth surface (S12) on the sensor side may be concave. The sixth lens (406) may have a meniscus shape that is convex toward the object side. The sixth lens (406) may have a meniscus shape that is concave toward the sensor side. The sixth lens (406) 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 of FIG. 32.

[0631] The eleventh surface (S11) of the sixth lens (406) may include a critical point from the optical axis (OA) to the end of the effective area. When the eleventh surface (S11) has a critical point, it may be located in a range of 55% to 70%, preferably 57% to 67%, of the effective radius (r61) from the optical axis (OA). The critical point of the eleventh surface (S11) may be located in a range of 1.3 mm to 1.7 mm, preferably 1.4 mm to 1.6 mm from the optical axis (OA).

[0632] The twelfth surface (S12) of the sixth lens (406) may include a critical point from the optical axis (OA) to the end of the effective area. When the twelfth surface (S12) has a critical point, it may be located in a range of 70% to 85%, preferably 72% to 80%, of the effective radius (r62) from the optical axis (OA). The critical point of the twelfth surface (S12) may be located in a range of 2.1 mm to 2.5 mm, preferably 2.2 mm to 2.4 mm from the optical axis (OA). The twelfth surface (S12) of the sixth lens (406) may have a gull-shaped shape in which the SAG value increases toward the end of the effective radius, thereby securing aberration characteristics.

[0633]

[0634] The sixth lens (406) may be a plastic lens closest to the image sensor (700). In addition, by arranging two or more plastic lenses adjacent to the image sensor (700), 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 (700), 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 (405, 406) adjacent to the image sensor (700) 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.

[0635]

[0636] LensSurfaceRadiusThicknessndvdSemiApertureFocal length1S110.5200.9071.8046.504.506-4.622S22.6512.1772.415 2S3-8.8792.5001.6719.002.11411.767S4-4.6810.5641.530 3S5(STOP)9.3111.5791.7749.830.8873.900S6-4.1250.2601.375 4S7-18.3410.4001.6719.001.459-3.670S82.9060.2311.777 5S95.2902.3001.5455.711.9663.090S10-2.0520.4582.290 6S113.9720.7441.6719.002.464-7.423S122.0520.4963.000 FilterS13Infinity0.8703.065S14Infinity0.6453.180ImageInfinity0.0053.314

[0637]

[0638] Fourth embodiment Fourth embodiment TTL 15.99 3ET 11.45 13F 2.15 7ET 22.59 35F no 2.39 8ET 31.29 35FOV_V 89.6ET 40.90 78FOV_H 150.3ET 50.79 14FOV_D 179.2ET 61.11 78EPD 0.90 0ImgH 6.62 8BFL 2.0 15SD(Stop~L6S2) 4.39TD(L1S1~L6S2) 12.12

[0639]

[0640] Tables 10 and 11 show the characteristics of an optical system according to a third embodiment of the present invention. Descriptions of the parameters included in Tables 10 and 11 are omitted as they overlap with those of the first embodiment of the present invention.

[0641]

[0642] The center thicknesses of the first to sixth lenses (401 to 406) are represented by CT1 to CT6, the edge thicknesses at the ends of the effective areas of each lens are represented by ET1 to ET6, the center gap between two adjacent lenses is represented by CG1 to CG5, and the edge gaps between the edges of each lens are represented by EG1 to EG5. The back focal length (BFL) is the optical axis distance from the image sensor (700) 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 (401) to the upper surface of the image sensor (700).

[0643] As shown in Fig. 32, among the lenses of the lens unit in the fourth embodiment, the lens surfaces of the second, fourth, fifth, and sixth lenses (402, 404, 405, and 406) may include aspherical surfaces having a 30th-order aspherical surface coefficient. For example, the second, fourth, fifth, and sixth lenses (402, 404, 405, and 406) 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 non-zero value) 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).

[0644] When comparing the absolute values ​​of the curvature radii of each lens, the curvature radii of the seventh surface (S7) of the fourth lens (404) on the optical axis (OA) may be the largest among the lenses, and the curvature radii of at least one of the tenth surface (S10) of the fifth lens (405) and the twelfth surface (S12) of the sixth lens (406) may be the smallest among the lenses. The difference between the maximum curvature radii and the minimum curvature radii may be 5 times or more, for example, 8 to 10 times.

[0645] 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.

[0646] The absolute value of the curvature radius of the first surface (S1) of the first lens (401) 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 (402) may be greater than the absolute value of the curvature radius of the fourth surface (S4). The absolute value of the curvature radius of the fifth surface (S5) of the third lens (403) 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 (404) 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 (405) may be greater than the absolute value of the curvature radius of the tenth surface (S10). The absolute value of the radius of curvature of the eleventh surface (S11) of the sixth lens (406) may be greater than the absolute value of the radius of curvature of the twelfth surface (S12).

[0647] The ratio of the radius of curvature of each lens can satisfy the following conditions.

[0648] Condition 1: 3 < |L1R1 / L1R2| < 5

[0649] Condition 2: 1 < |L2R1 / L2R2| < 3

[0650] Condition 3: 1 < |L3R1 / L3R2| < 3

[0651] Condition 4: 5 < |L4R1 / L4R2| < 8

[0652] Condition 5: 2 < |L5R1 / L5R2| < 4

[0653] Condition 6: 1 < |L6R1 / L6R2| < 3

[0654]

[0655] When describing the central thickness (CT) of the lenses based on the optical axis, the central thickness (CT2) of the second lens (402) is the largest among the lenses, and the central thickness (CT4) of the fourth lens (404) 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.

[0656] The central thickness of each lens may satisfy any one of the following conditions:

[0657] Condition 1: CT2, CT3, CT5 > CT1 > CT4, CT6

[0658] Condition 2: CT2 > CT1, CT3, CT4, CT5, CT6

[0659] Condition 3: CT2, CT5 > CT3 > CT1, CT4, CT6

[0660] Condition 4: CT1, CT2, CT3, CT5, CT6 > CT4

[0661] Condition 5: CT2 > CT5 > CT1, CT3, CT4, CT6

[0662] Condition 6: CT1, CT2, CT3, CT5 > CT6 > CT4

[0663]

[0664] When describing the center spacing (CG) between the lenses, the center spacing (CG1) between the first lens (401) and the second lens (402) may be the maximum, and the center spacing (CG4) between the fourth and fifth lenses (404, 405) may be the minimum. The difference between the maximum center spacing and the minimum center spacing among the spaced lenses may be 1.5 mm or more, for example, in the range of 1.6 mm to 2 mm.

[0665] The center spacing between each lens can satisfy the conditions below.

[0666] Condition 1: CG1 > CG2, CG3, CG4, CG5

[0667] Condition 2: CG1 > CG2 > CG3, CG4, CG5

[0668] Condition 3: CG1, CG2, CG5 > CG3 > CG4

[0669] Condition 4: CG1, CG2, CG3, CG5 > CG4

[0670] Condition 5: CG1, CG2 > CG5 > CG3, CG4

[0671]

[0672] 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 (401). 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 (401).

[0673] The lens having the minimum effective diameter may be a lens arranged between the aperture (STOP) and the sixth lens (406). The lens having the minimum effective diameter may be the third lens (403). The lens surface having the minimum effective diameter may be the fifth surface (S5) of the third lens (403). 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.

[0674] The effective diameter of each lens can satisfy any one of the conditions below.

[0675] Condition 1: CA_L1 > CA_L2, CA_L3, CA_L4, CA_L5, CA_L6

[0676] Condition 2: CA_L1, CA_L5, CA_L6 > CA_L2 > CA_L3, CA_L4

[0677] Condition 3: CA_L1, CA_L2, CA_L4, CA_L5, CA_L6 > CA_L3

[0678] Condition 4: CA_L1, CA_L2, CA_L5, CA_L6 > CA_L4 > CA_L3

[0679] Condition 5: CA_L1, CA_L6 > CA_L5 > CA_L2, CA_L3, CA_L4

[0680] Condition 6: CA_L1 > CA_L6 > CA_L2, CA_L3, CA_L4, CA_L5

[0681]

[0682] In terms of refractive index, the refractive index of the first lens (401) is the largest among the lenses and may be greater than 1.7, for example, greater than 1.75. The refractive index of the fifth lens (405) is 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 (700) 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 (700).

[0683] The refractive index of each lens can satisfy any of the conditions below.

[0684] Condition 1: n1 > n2, n3, n4, n5, n6

[0685] Condition 2: n1, n3 > n2 = n4 = n6 > n5

[0686] Condition 3: n1 > n3 > n2, n4, n5, n6

[0687] Condition 4: n1, n2, n3, n4, n6 > n5

[0688]

[0689] Comparing the Abbe numbers, the Abbe number of the fifth lens (405) is the largest among the lenses and may be 45 or more. The Abbe number of at least one of the second lens (402), the fourth lens (404), and the sixth lens (406) 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 30 or more. By providing the largest Abbe number of the third lens (403) arranged at the center of the optical system (1300) and the smallest Abbe number of the sixth lens (406) having a low refractive index adjacent to the image sensor (700), 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 (700).

[0690] The Abbe number of each lens can satisfy any of the conditions below.

[0691] Condition 1: v3, v5 > v1 > v2, v4, v6

[0692] Condition 2: v1, v3, v5 > v2 = v4 = v6

[0693] Condition 3: v5 > v3 > v1, v2, v4, v6

[0694] Condition 4: v5 > v1, v2, v3, v4, v6

[0695]

[0696] The focal lengths (F1, F4, F6) of the first, fourth, and sixth lenses (401, 404, and 406) may have negative (-) signs. The first, fourth, and sixth lenses (401, 404, and 406) may have negative (-) refractive power. The focal lengths (F2, F3, and F5) of the second, third, and fifth lenses (402, 403, and 405) may have positive (+) signs. The second, third, and fifth lenses (402, 403, and 405) may have positive (+) refractive power.

[0697]

[0698] When comparing the focal lengths in absolute values, the focal length of the second lens (402) is the largest among the lenses, and may be 8 or more and 12 or less. The focal length of the fifth lens (405) is the smallest among the lenses, and the absolute value of the focal length of the fifth lens (405) may be 2 or more and 4 or less.

[0699] The absolute value of the focal length of each lens can satisfy any of the conditions below.

[0700] Condition 1: |f2|, |f6| > |f1| > |f3|, |f4|, |f5|

[0701] Condition 2: |f2| > |f1|, |f3|, |f4|, |f5|, |f6|

[0702] Condition 3: |f1|, |f2|, |f6| > |f3| > |f4|, |f5|

[0703] Condition 4: |f1|, |f2|, |f3|, |f6| > |f4| > |f5|

[0704] Condition 5: |f1|, |f2|, |f3|, |f4|, |f6| > |f5|

[0705] Condition 6: |f2| > |f6| > |f1|, |f3|, |f4|, |f5|

[0706]

[0707] Any one of the fourth to sixth lenses (404-406) made of a plastic material and arranged adjacent to the sensor side may have a different refractive power from the other two. For example, the fourth and sixth lenses (404, 406) may have a negative (-) refractive power, and the fifth lens (405) may have a positive (+) refractive power. The absolute value of the focal length of one lens among the fourth to sixth lenses (404-406) having a different refractive power from the other two may be smaller than the absolute values ​​of the focal lengths of the other two. The refractive power of one lens among the fourth to sixth lenses (404-406) having a different refractive power from the other two may be larger than the refractive powers of the other two. For example, the absolute value of the focal length of the fifth lens (405) having a positive (+) refractive power may be smaller than the absolute values ​​of the focal lengths of the fourth and sixth lenses (404, 406) having a negative (-) refractive power.

[0708] Since the plastic lens disposed adjacent to the image sensor (700) is sensitive to temperature changes, the composite refractive power of the plastic lens can be designed to be close to 0. In other words, the composite refractive power of the plastic lens disposed adjacent to the image sensor (700) can be reduced. Through this, the refractive power of the plastic lens, which is sensitive to temperature changes, can be offset within the plastic lens, thereby minimizing changes in the performance of the overall optical system, and minimizing the influence of the plastic lens on the optical performance of the overall optical system (1300).

[0709] The ratio of the absolute values ​​of the focal lengths of the glass lenses included in the optical system (1300) can satisfy a value of 0.8 or more and 1.2 or less. For example, the absolute value (|f1| / |f3|) of the ratio of the focal lengths of the first lens (401) and the third lens (403) made of glass can satisfy a value of 0.8 or more and 1.2 or less. In addition, the signs of the focal lengths of the first lens (401) and the third lens (403) made of glass can be different from each other. Through this, the overall refractive power of the optical system (1300) can be greatly affected by the glass lens that is strong against temperature changes.

[0710]

[0711] The thickness (T1) of the first lens (401) may be a difference of 1 or more times, for example, 1.5 to 2 times, between the maximum thickness and the minimum thickness, 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 (402) may be a maximum thickness in a range of 1 to 1.3 times the minimum thickness. The second lens (402) may be a minimum in the center thickness (CT2) and the maximum in the edge thickness (ET2). The thickness (T3) of the third lens (403) may be a maximum in the center and a minimum in the edge, and the maximum thickness is a range of 1 to 1.5 times the minimum thickness. The thickness (T4) of the fourth lens (404) may be a minimum in the center and a maximum in the edge, and the maximum thickness is a range of 2 to 2.5 times the minimum thickness. The thickness (T5) of the fifth lens (405) may be maximum at the center and minimum at the edge, and the maximum thickness is in the range of 2.5 to 3.5 times the minimum thickness. The thickness (T6) of the sixth lens (406) may be maximum at the center and minimum at the edge, and the maximum thickness is in the range of 1 to 2 times the minimum thickness.

[0712] 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.

[0713] The thickness of each lens can satisfy any of the conditions below.

[0714] Condition 1: 0.5 < CT1 / ET1 < 1, 1.5 < ET1 / CT1 < 2

[0715] Condition 2: 0.5 < CT2 / ET2 < 1, 0.8 < ET2 / CT2 < 1.3

[0716] Condition 3: 1 < CT3 / ET3 < 1.5, 0.5 < ET3 / CT3 < 1

[0717] Condition 4: 0.1 < CT4 / ET4 < 1, 2 < ET4 / CT4 < 2.5

[0718] Condition 5: 2.5 < CT5 / ET5 < 3.5, 0.1 < ET5 / CT5 < 0.5

[0719] Condition 6: 0.5 < CT6 / ET6 < 1, 1 < ET6 / CT6 < 2

[0720] Condition 7: 0.8 < ΣCT / ΣET < 1.2, 0.5 < ΣET / ΣCT < 1

[0721]

[0722] Among the gaps (G1-G7) between the lenses, the first gap (G1) between the first and second lenses (401, 402) may have a maximum in the center and a minimum in the edge. The second gap (G2) between the second and third lenses (402, 403) may have a minimum in the center and a maximum in the edge. The third gap (G3) between the third and fourth lenses (403, 404) may have a maximum in the edge and a minimum in the center. The fourth gap (G4) between the fourth and fifth lenses (404, 405) may have a maximum in the center and a minimum in the edge. The fifth gap (G5) between the fifth and sixth lenses (405, 406) may have a minimum in the center and a maximum in the edge.

[0723]

[0724] FIGS. 31, 32, and 33 are graphs showing the diffraction MTF (Modulation Transfer Function) at room temperature, low temperature, and high temperature in the optical system of FIG. 28, and are graphs showing the modulation ratio according to spatial frequency. As shown in FIGS. 31, 32, and 33, in the fourth 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.

[0725] Fig. 34 is a graph showing the aberration characteristics at RGB wavelengths at room temperature in the optical system of Fig. 28. In the aberration graph of Fig. 34, spherical aberration (longitudinal spherical aberration), astigmatic field curves, and distortion are measured from left to right. In Fig. 34, the X-axis may represent the focal length (mm) and the degree of distortion (%), and the Y-axis may represent the height of the image. In addition, the graph for spherical aberration is a graph for light in wavelength bands of about 435 nm, about 486 nm, about 546 nm, about 587 nm, and about 656 nm, and the graphs for astigmatism and distortion are graphs for light in wavelength bands of about 546 nm. In the aberration diagram of Fig. 34, the closer each curve is to the Y-axis, the better the aberration correction function can be interpreted. It can be seen that the optical system (1300) according to the fourth embodiment has measured values ​​close to the Y-axis in almost all areas. That is, the optical system (1300) according to the fourth 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 degrees to 105 degrees.

[0726] Table 12 shows changes in optical characteristics such as EFL and field of view (FOV_H) at room temperature, low temperature, and high temperature in the optical system according to the fourth embodiment. It can be seen that the change rate of the 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 the optical characteristics at low temperature is 5% or less, for example, 3% or less, based on room temperature. In addition, Table 12 compares the MTF focus position shift in the optical system according to the fourth embodiment, and the MTF focus position shift at low and high temperatures can satisfy a range of 10 um or less based on room temperature, and can satisfy a range of 5 um or less, for example.

[0727] Room temperature low temperature high temperature low temperature / Room temperature high temperature / Room temperature EFL(F) 2.1567 2.1482 2.169899.6% 100.60% FOV_H 150 150.9 149.6 100.6% 99.73% MTF focus position Shift 0um-3um+4um--

[0728]

[0729] Therefore, as shown in Table 12, 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) and the change rate of horizontal 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.

[0730] The optical system of the fourth 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.

[0731]

[0732] Below, the configuration of an optical system according to a fifth embodiment of the present invention is described with reference to the drawings.

[0733] An optical system according to the fifth embodiment includes a lens unit, and the lens unit may include a first lens (501) to a sixth lens (506). The first to sixth lenses (501, 502, 503, 504, 505, 506) may be sequentially arranged along an optical axis (OA). Light corresponding to information about an object may pass through the first lens (501) to the sixth lens (506) and a filter (800) and be incident on an image sensor (700).

[0734] The lens section may be arranged in order from the object side to the image side, including a first lens (501), a second lens (502), a third lens (503), an aperture (STOP), a fourth lens (504), a fifth lens (505), and a sixth lens (506).

[0735] In another embodiment, one or more of another lens, a flat plate, and an optical member may be added between the first lens (501) to the sixth lens (506). In addition, one or more of another lens, a flat plate, and an optical member may be added in front of the first lens (501) or behind the sixth lens (506). 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 (800), and between the filter (800) and the image sensor (700). In this case, the filter (800) 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 (800), and between the filter (800) and the image sensor (700). In this case, the filter layer may be coated to become a filter.

[0736] The first lens (501) may be arranged closest to the object side. The first lens (501) may be arranged farthest from the sensor side. The first lens (501) may have negative (-) refractive power on the optical axis (OA). The first lens (501) may include a plastic material or a glass material, and may be made of glass, for example. The first lens (501) made of glass may reduce changes in the center position and radius of curvature due to temperature changes in the surrounding environment, and may protect the incident side of the optical system (1400).

[0737] The first surface (S1) on the object side of the first lens (501) with respect to the optical axis may be convex, and the second surface (S2) on the sensor side may be concave. The first lens (501) may have a meniscus shape that is convex toward the object side. The first lens (501) 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.

[0738] Due to the refractive characteristics of the first lens (501), the second lens (502) can be further separated from the first lens (501). That is, the center spacing between the first and second lenses (501, 502) can be the largest within the lens unit.

[0739] The refractive index (n1) of the first lens (501) can satisfy the condition of n1>1.75 or n1>1.8. The radius of curvature of the first and second lenses (501, 502) can be increased, and lens manufacturing can be facilitated. If the refractive index (n1) of the first lens (501) 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 (501, 502). In this case, lens manufacturing is not easy, the lens defect rate increases, and it may cause a decrease in yield.

[0740]

[0741] The second lens (502) may be arranged second from the object side. The second lens (502) may be arranged fifth from the sensor side. The second lens (502) may be arranged between the first lens (501) and the third lens (503). The second lens (502) may have negative refractive power in the optical axis (OA). The second lens (502) may include a plastic or glass material. For example, the second lens (502) may be provided as a plastic material.

[0742] The third surface (S3) on the object side of the second lens (502) with respect to the optical axis (OA) may be concave, and the fourth surface (S4) on the sensor side may be convex. The second lens (502) may have a meniscus shape that is convex toward the sensor side. The second lens (502) may have a meniscus shape that is concave toward the object side. Since the second lens (502) functions to gather light onto the optical axis through the meniscus shape that is convex toward the sensor side, the effective diameter of the first lens (501) can be reduced, and the optical system can be miniaturized.

[0743] The second lens (502) may be made of plastic and may be aspherical. At least one or both of the third surface (S3) and the fourth surface (S4) may be aspherical. The aspherical coefficients of the third and fourth surfaces (S3, S4) may be provided as S1 and S2 of L2 in FIG. 36. 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.

[0744]

[0745] The third lens (503) may be arranged third from the object side. The third lens (503) may be arranged fourth from the sensor side. The third lens (503) may be arranged between the second lens (502) and the fourth lens (504). The third lens (503) may have positive (+) refractive power on the optical axis (OA). The third lens (503) may include a plastic or glass material. For example, the third lens (503) may be provided as a glass material.

[0746] The fifth surface (S5) on the object side of the third lens (503) with respect to the optical axis may be convex, and the sixth surface (S6) on the sensor side may be concave. The third lens (503) may have a convex meniscus shape toward the object side. The third lens (503) may have a concave meniscus shape toward the sensor side. The third lens (503) may be made of glass and may be spherical.

[0747] The aperture (Stop) may be arranged around the sensor-side sixth surface (S6) of the third lens (503). The aperture (Stop) may be arranged around the object-side eighth surface (S8) of the fourth lens (504). The aperture can reduce the TTL within the field of view range, enabling miniaturization of the optical system. Accordingly, a decrease in the yield by weight of the optical system can be prevented, and production efficiency can be improved. In addition, the optical system can be miniaturized by reducing the TTL within the horizontal field of view (FOV_H) of 130 to 150 degrees.

[0748] A field stop may be arranged between the third lens (503) and the fourth lens (504). The field stop may be formed so that the surface facing the optical axis of the spacer has a protruding shape or a sharp surface. The third lens (503) and the fourth lens (504) are lenses arranged in the central region of the optical system (1400), and may have an effective diameter smaller than the first lens (501) arranged on the object side and the sixth lens (506) arranged on the sensor side. Therefore, in order to prevent a ghost phenomenon due to diffuse reflection and to prevent the introduction of stray light, a field stop may be additionally arranged between the third lens (503) and the fourth lens (504).

[0749]

[0750] The fourth lens (504) may be arranged fourth from the object side. The fourth lens (504) may be arranged third from the sensor side. The fourth lens (504) may be arranged between the third lens (503) and the fifth lens (505). The fourth lens (504) may have positive (+) or negative (-) refractive power on the optical axis (OA). The fourth lens (504) may have positive (+) refractive power. The fourth lens (504) may include a plastic or glass material. For example, the fourth lens (504) may be provided as a plastic material.

[0751] The object-side seventh surface (S7) of the fourth lens (504) with respect to the optical axis may be convex, and the sensor-side eighth surface (S8) may be convex. The fourth lens (504) may have a convex shape on both sides. The fourth lens (504) 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. 36. 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.

[0752]

[0753] The fifth lens (505) may be arranged as the fifth lens from the object side. The fifth lens (505) may be arranged as the second lens from the sensor side. The fifth lens (505) may be arranged between the fourth lens (504) and the sixth lens (506). The fifth lens (505) may have positive (+) or negative (-) refractive power on the optical axis (OA). The fifth lens (505) may have negative (-) refractive power. The fifth lens (505) may include a plastic or glass material. For example, the fifth lens (505) may be provided as a plastic material.

[0754] With respect to the optical axis (OA), the ninth surface (S9) on the object side of the fifth lens (505) may be concave, and the tenth surface (S10) on the sensor side may be concave. The fifth lens (505) may have a concave shape on both sides. The fifth lens (505) may be made of a plastic material and may be aspherical. At least one or both of the ninth surface (S9) and the tenth surface (S10) may be aspherical. The aspherical coefficients of the ninth and tenth surfaces (S9, S10) may be provided as S1 and S2 of L5 in FIG. 36. 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.

[0755]

[0756] The fourth lens (504) and the fifth lens (505), which are joined lenses, can satisfy the following conditions.

[0757] Condition 1: Refractive index of lens with positive refractive power < refractive index of lens with negative refractive power

[0758] Condition 2: Dispersion of a lens with positive refractive power > Dispersion of a lens with negative refractive power

[0759] Here, among the plastic lenses, the fourth lens (504) has positive refractive power and the fifth lens (505) has negative refractive power, so that according to conditions 1 and 2, the refractive index of the fourth lens (504) is smaller than the refractive index of the fifth lens (505), and the dispersion value of the fourth lens (504) is larger than the dispersion value of the fifth lens (505). The chromatic aberration occurring in the plastic lens can be corrected by the plastic lens. In addition, since the fifth lens (505) and the fourth lens (504), which are plastic lenses arranged in succession, satisfy the refractive index difference of 0.1 or more and 0.15 or less and the Abbe number difference of 20 or more and 40 or less, the chromatic aberration occurring in the plastic lens can be compensated for by the plastic lens.

[0760] 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 fifth embodiment of the present invention, chromatic aberration occurring in a plastic lens can be corrected by using the fourth lens (504) and the fifth lens (505).

[0761]

[0762] The sixth lens (506) may be positioned furthest from the object side. The sixth lens (506) may be positioned closest to the image sensor (700). The sixth lens (506) may have positive (+) or negative (-) refractive power on the optical axis (OA). The sixth lens (506) may have positive (+) refractive power. The sixth lens (506) may include a plastic or glass material. For example, the sixth lens (506) may be provided with a plastic material.

[0763] With respect to the optical axis (OA), the eleventh surface (S11) on the object side of the sixth lens (506) may be convex, and the twelfth surface (S12) on the sensor side may be concave. The sixth lens (506) may have a meniscus shape that is convex toward the object side. The sixth lens (506) may have a meniscus shape that is concave toward the sensor side. The sixth lens (506) 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 of FIG. 36. The eleventh surface (S11) and the twelfth surface (S12) of the sixth lens (506) may be provided without critical points from the optical axis (OA) to the ends of the effective areas.

[0764]

[0765] The sixth lens (506) may be a plastic lens closest to the image sensor (700). In addition, by arranging two or more plastic lenses adjacent to the image sensor (700), 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 (700), 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 (505, 506) adjacent to the image sensor (700) 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.

[0766]

[0767] LensSurfaceRadiusThicknessndvdSemiApertureFocal length1S111.8711.6231.82445.277-5.736S23.1672.9812.780 2S3-3.0612.4921.54532.243-10.243S4-8.8390.1001.766 3S531.5161.91351.5974.301S623.9171.3011.150 4S7(STOP)3.4041.0191.54560.8991.946S8-1.3510.0001.031 5S9-1.3510.8541.64221.031-1.865S1014.5800.7381.425 6S114.1910.9311.67192.56511.779S128.0080.2042.577 FilterS13Infinity1.0002.587S14Infinity1.0002.769ImageInfinity0.0003.050

[0768]

[0769] Example 5 Example 5 TTL 15.76 1ET 12.09 40F 2.5 14ET 23.39 73F no 2.39 5ET 30.83 75FOV_V 5 0 1.1ET 40.39 21FOV_H 140.0ET 5 1.41 28FOV_D 15 0.4ET 60.48 93EPD 1.049ImgH 6.100BFL 2.20 4SD(Stop~L6S2) 4.84TD(L1S1~L6S2) 13.56

[0770]

[0771] Tables 13 and 14 show the characteristics of the optical system according to the fifth embodiment of the present invention. Descriptions of the parameters included in Tables 13 and 14 are omitted as they overlap with those of the first embodiment of the present invention.

[0772]

[0773] The center thicknesses of the first to sixth lenses (501 to 506) are represented by CT1 to CT6, the edge thicknesses at the ends of the effective areas of each lens are represented by ET1 to ET6, the center gap between two adjacent lenses is represented by CG1 to CG5, and the edge gaps between the edges of each lens are represented by EG1 to EG5. The BFL (Back focal length) is the optical axis distance from the image sensor (700) 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 (501) to the upper surface of the image sensor (700).

[0774] As shown in Fig. 36, among the lenses of the lens unit of the fifth embodiment, the lens surfaces of the second, fourth, fifth, and sixth lenses (502, 504, 505, and 506) may include aspherical surfaces having a 30th-order aspherical surface coefficient. For example, the second, fourth, fifth, and sixth lenses (502, 504, 505, and 506) may include lens surfaces having a 30th-order aspherical surface coefficient. As described above, the aspherical surface having a 30th-order aspherical surface coefficient (a value other than "0") can significantly change the aspherical shape of the peripheral portion, and thus can effectively correct the optical performance of the peripheral portion of the field of view (FOV).

[0775] When comparing the absolute values ​​of the curvature radii of each lens, the curvature radii of the sixth surface (S6) of the third lens (503) on the optical axis (OA) may be the largest among the lenses, and the curvature radii of the seventh surface (S7) of the fourth lens (504) and the ninth surface (S9) of the fifth lens (505) may be the smallest among the lenses. The difference between the maximum curvature radii and the minimum curvature radii may be 15 times or more, for example, in the range of 18 to 25 times.

[0776] 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.

[0777] The absolute value of the curvature radius of the first surface (S1) of the first lens (501) 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 (502) 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 (503) may be less 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 (504) 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 (505) may be less than the absolute value of the curvature radius of the tenth surface (S10). The absolute value of the radius of curvature of the eleventh surface (S11) of the sixth lens (506) may be smaller than the absolute value of the radius of curvature of the twelfth surface (S12).

[0778] The ratio of the radius of curvature of each lens can satisfy the following conditions.

[0779] Condition 1: 3 < |L1R1 / L1R2| < 5

[0780] Condition 2: 0.1 < |L2R1 / L2R2| < 0.5

[0781] Condition 3: 0.1 < |L3R1 / L3R2| < 0.5

[0782] Condition 4: 2 < |L4R1 / L4R2| < 4

[0783] Condition 5: 0.01 < |L5R1 / L5R2| < 0.2

[0784] Condition 6: 0.1 < |L6R1 / L6R2| < 1

[0785]

[0786] When describing the central thickness (CT) of the lenses based on the optical axis, the central thickness (CT2) of the second lens (502) is the largest among the lenses, and the central thickness (CT5) of the fifth lens (505) is the smallest among the lenses. The difference between the maximum and minimum central thicknesses among the lenses may be in the range of 1.3 mm or more and 2 mm or less.

[0787] The central thickness of each lens may satisfy any one of the following conditions:

[0788] Condition 1: CT2 > CT1 > CT3, CT4, CT5, CT6

[0789] Condition 2: CT2 > CT1, CT3, CT4, CT5, CT6

[0790] Condition 3: CT1, CT2 > CT3 > CT4, CT5, CT6

[0791] Condition 4: CT1, CT2, CT3 > CT4 > CT5, CT6

[0792] Condition 5: CT1, CT2, CT3, CT4, CT6 > CT5

[0793] Condition 6: CT1, CT2, CT3, CT4 > CT6 > CT5

[0794]

[0795] When describing the center spacing (CG) between the lenses, the center spacing (CG1) between the first lens (501) and the second lens (502) may be maximum, and the center spacing (CG2) between the second and third lenses (502, 503) 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 mm.

[0796] The center spacing between each lens can satisfy the conditions below.

[0797] Condition 1: CG1 > CG2, CG3, CG5

[0798] Condition 2: CG1, CG3, CG5 > CG2

[0799] Condition 3: CG1 > CG3 > CG2, CG5

[0800] Condition 4: CG1, CG3 > CG5 > CG2

[0801]

[0802] 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 (501). 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 (501).

[0803] The lens having the minimum effective diameter may be a lens arranged between the aperture (STOP) and the sixth lens (506). The lens having the minimum effective diameter may be the fourth lens (504). The lens surfaces having the minimum effective diameter may be the eighth surface (S8) of the fourth lens (504) and the ninth surface (S9) of the fifth lens (505). The effective diameter of the lens made of plastic may be smaller than that of the lens made of glass. The lens made of plastic may be arranged adjacent to the image sensor.

[0804] The effective diameter of each lens can satisfy any one of the conditions below.

[0805] Condition 1: CA_L1 > CA_L2, CA_L3, CA_L4, CA_L5, CA_L6

[0806] Condition 2: CA_L1, CA_L6 > CA_L2 > CA_L3, CA_L4, CA_L5

[0807] Condition 3: CA_L1, CA_L2, CA_L6 > CA_L3 > CA_L4, CA_L5

[0808] Condition 4: CA_L1, CA_L2, CA_L3, CA_L5, CA_L6 > CA_L4

[0809] Condition 5: CA_L1, CA_L2, CA_L3, CA_L6 > CA_L5 > CA_L4

[0810] Condition 6: CA_L1 > CA_L6 > CA_L2, CA_L3, CA_L4, CA_L5

[0811]

[0812] In terms of refractive index, the refractive index of the third lens (503) may be the largest among the lenses and may be greater than 1.85, for example, greater than 1.9. Either or both of the second lens (502) and the fourth lens (504) may have the smallest refractive index among the lenses. For example, the refractive index of the second lens (502) and the fourth lens (504) 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 (700) 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 (700).

[0813] The refractive index of each lens can satisfy any of the conditions below.

[0814] Condition 1: n3 > n1 > n2, n4, n5, n6

[0815] Condition 2: n1, n3, n5, n6 > n2 = n4

[0816] Condition 3: n3 > n1, n2, n4, n5, n6

[0817] Condition 4: n1, n2, n3, n4 > n5 > n6

[0818] Condition 5: n1, n3 > n6 > n2, n4, n5

[0819]

[0820] Comparing the Abbe numbers, the Abbe number of the fourth lens (504) is the largest among the lenses and may be 50 or more. The Abbe number of the sixth lens (506) 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 making the Abbe number of the fourth lens (504) arranged at the center of the optical system (1400) the largest and providing the Abbe number of the sixth lens (506) having a low refractive index adjacent to the image sensor (700) 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 it to the image sensor (700).

[0821] The Abbe number of each lens can satisfy any of the conditions below.

[0822] Condition 1: v2, v4 > v1 > v3, v5, v6

[0823] Condition 2: v4 > v2 > v1, v3, v5, v6

[0824] Condition 3: v1, v2, v4 > v3 > v5, v6

[0825] Condition 4: v4 > v1, v2, v3, v5, v6

[0826] Condition 5: v1, v2, v3, v4 > v5 > v6

[0827] Condition 6: v1, v2, v3, v4, v5 > v6

[0828]

[0829] The focal lengths (F1, F2, F5) of the first, second, and fifth lenses (501, 502, and 505) may have negative (-) signs. The first, second, and fifth lenses (501, 502, and 505) may have negative (-) refractive power. The focal lengths (F3, F4, and F6) of the third, fourth, and sixth lenses (503, 504, and 506) may have positive (+) signs. The third, fourth, and sixth lenses (503, 504, and 506) may have positive (+) refractive power.

[0830] When comparing the focal lengths in absolute values, the focal length of the sixth lens (506) is the largest among the lenses, and may be 10 or more and 20 or less. The focal length of the fifth lens (505) is the smallest among the lenses, and the absolute value of the focal length of the fifth lens (505) may be 1 or more and 3 or less.

[0831] The absolute value of the focal length of each lens can satisfy any of the conditions below.

[0832] Condition 1: |f2|, |f6| > |f1| > |f3|, |f4|, |f5|

[0833] Condition 2: |f6| > |f2| > |f1|, |f3|, |f4|, |f5|

[0834] Condition 3: |f1|, |f2|, |f6| > |f3| > |f4|, |f5|

[0835] Condition 4: |f1|, |f2|, |f3|, |f6| > |f4| > |f5|

[0836] Condition 5: |f1|, |f2|, |f3|, |f4|, |f6| > |f5|

[0837] Condition 6: |f6| > |f1|, |f2|, |f3|, |f4|, |f5|

[0838]

[0839] Any one of the fourth to sixth lenses (504-506) made of a plastic material and arranged adjacent to the sensor side may have a different refractive power from the other two. For example, the fourth and sixth lenses (504, 506) may have positive (+) refractive power, and the fifth lens (505) may have negative (-) refractive power. The absolute value of the focal length of one lens among the fourth to sixth lenses (504-506) having a different refractive power from the other two may be smaller than the absolute values ​​of the focal lengths of the other two. The refractive power of one lens among the fourth to sixth lenses (504-506) having a different refractive power from the other two may be larger than the refractive powers of the other two. For example, the absolute value of the focal length of the fifth lens (505) having a negative (-) refractive power may be smaller than the focal lengths of the fourth and sixth lenses (504, 506) having a positive (+) refractive power.

[0840] Since the plastic lens disposed adjacent to the image sensor (700) is sensitive to temperature changes, the composite refractive power of the plastic lens can be designed to be close to 0. In other words, the composite refractive power of the plastic lens disposed adjacent to the image sensor (700) can be reduced. Through this, the refractive power of the plastic lens, which is sensitive to temperature changes, can be offset within the plastic lens, thereby minimizing changes in the performance of the overall optical system, and minimizing the influence of the plastic lens on the optical performance of the overall optical system (1400).

[0841] The ratio of the absolute values ​​of the focal lengths of the glass lenses included in the optical system (1400) can satisfy a value of 0.8 or more and 1.6 or less. For example, the absolute value (|f1| / |f3|) of the ratio of the focal lengths of the first lens (501) and the third lens (503) made of glass can satisfy a value of 0.8 or more and 1.6 or less. In addition, the signs of the focal lengths of the first lens (501) and the third lens (503) made of glass can be different from each other. Through this, the overall refractive power of the optical system (1400) can be greatly affected by the glass lens that is strong against temperature changes.

[0842]

[0843] The thickness (T1) of the first lens (501) may be a difference of at least twice the maximum thickness and the minimum thickness, for example, in the range of 2.1 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 (502) may be a maximum thickness in the range of 1 to 1.3 times the minimum thickness. The second lens (502) may be a minimum in the center thickness (CT2) and the maximum in the edge thickness (ET2). The thickness (T3) of the third lens (503) may be a maximum in the center and a minimum in the edge, and the maximum thickness is in the range of 1 to 1.5 times the minimum thickness. The thickness (T4) of the fourth lens (504) may be a minimum in the center and a maximum in the edge, and the maximum thickness is in the range of 2 to 2.5 times the minimum thickness. The thickness (T5) of the fifth lens (505) may be maximum at the center and minimum at the edge, and the maximum thickness is in the range of 1 to 1.5 times the minimum thickness. The thickness (T6) of the sixth lens (506) 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.

[0844] 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.

[0845] The thickness of each lens can satisfy any of the conditions below.

[0846] Condition 1: 0.5 < CT1 / ET1 < 1, 1 < ET1 / CT1 < 1.5

[0847] Condition 2: 0.5 < CT2 / ET2 < 1, 1 < ET2 / CT2 < 1.5

[0848] Condition 3: 1.5 < CT3 / ET3 < 1, 0.3 < ET3 / CT3 < 0.8

[0849] Condition 4: 2.3 < CT4 / ET4 < 2.8, 0.1 < ET4 / CT4 < 0.5

[0850] Condition 5: 0.5 < CT5 / ET5 < 1, 1.5 < ET5 / CT5 < 2

[0851] Condition 6: 1.5 < CT6 / ET6 < 2, 0.3 < ET6 / CT6 < 0.8

[0852] Condition 7: 0.5 < ΣCT / ΣET < 1, 1 < ΣET / ΣCT < 1.5

[0853]

[0854] Among the gaps (G1-G7) between the lenses, the first gap (G1) between the first and second lenses (501, 502) may have a maximum in the center and a minimum in the edge. The second gap (G2) between the second and third lenses (502, 503) may have a minimum in the center and a maximum in the edge. The third gap (G3) between the third and fourth lenses (503, 504) may have a maximum in the edge and a minimum in the center. The fifth gap (G5) between the fifth and sixth lenses (505, 506) may have a minimum in the center and a maximum in the edge.

[0855]

[0856] FIGS. 38, 39, and 40 are graphs showing the diffraction MTF (Modulation Transfer Function) of RGB wavelengths at room temperature, low temperature, and high temperature in the optical system of FIG. 35, and are graphs showing the modulation ratio according to the spatial frequency. As shown in FIGS. 38, 39, and 40, in the fifth 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. Here, the RGB wavelength may satisfy the visible light region of 435 nm to 650 nm.

[0857] FIGS. 41, 42, and 43 are graphs showing the diffraction MTF (Modulation Transfer Function) of RGB wavelengths at room temperature, low temperature, and high temperature in the optical system of FIG. 35, and are graphs showing the luminance ratio (modulation) according to spatial frequency. As shown in FIGS. 41, 42, and 43, in the fifth 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. Here, the IR wavelength may satisfy a range of 820 nm to 980 nm or other regions.

[0858] Fig. 44 is a graph showing the aberration characteristics at RGB wavelengths at room temperature in the optical system of Fig. 35. In the aberration graph of Fig. 44, spherical aberration (longitudinal spherical aberration), astigmatic field curves, and distortion are measured from left to right. In Fig. 44, the X-axis may represent the focal length (mm) and the degree of distortion (%), and the Y-axis may represent the height of the image. In addition, the graph for spherical aberration is a graph for light in wavelength bands of about 435 nm, about 486 nm, about 546 nm, about 587 nm, and about 656 nm, and the graphs for astigmatism and distortion are graphs for light in wavelength bands of about 546 nm. In the aberration diagram of Fig. 44, the closer each curve is to the Y-axis, the better the aberration correction function can be interpreted. It can be seen that the optical system (1400) according to the fifth embodiment has measured values ​​close to the Y-axis in almost all areas. That is, the optical system (1400) according to the fifth 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 505 degrees.

[0859] Table 15 shows changes in optical characteristics such as EFL and field of view (FOV_H) at room temperature, low temperature, and high temperature in the optical system according to the fifth embodiment. It can be seen that the change rate of the 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 the optical characteristics at low temperature is 5% or less, for example, 3% or less, based on room temperature. In addition, Table 15 compares the MTF focus position shift at RGB wavelength and the MTF focus position shift at IR wavelength in the optical system according to the fifth embodiment, and the MTF focus position shift at low temperature and high temperature can satisfy a range of 10 um or less based on room temperature, and can satisfy a range of 8 um or less, for example.

[0860]

[0861] Room temperature low temperature high temperature low temperature / room temperature high temperature / room temperature EFL(F) 2.5 1 3 8 2.4 8 7 12.5 4 7 3 9 8.93% 50 1.33% FOV_H 1 4 0 1 4 2.3 1 3 7.2 5 0 1.64% 98% MTF focus position Shift (RGB wavelength) 0 um - 3 um + 4 um -- MTF focus position Shift (IR wavelength) 0 um - 3 um + 4 um --

[0862]

[0863] Therefore, as shown in Table 15, 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) and the change rate of horizontal 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.

[0864] The optical system of the fifth 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.

[0865]

[0866] Below, the configuration of an optical system according to a sixth embodiment of the present invention is described with reference to the drawings.

[0867] An optical system according to the sixth embodiment includes a lens unit, and the lens unit may include a first lens (601) to a sixth lens (606). The first to sixth lenses (601, 602, 603, 604, 605, 606) may be sequentially arranged along an optical axis (OA). Light corresponding to information about an object may pass through the first lens (601) to the sixth lens (606) and a filter (800) and be incident on an image sensor (700).

[0868] The lens section may be arranged in order from the object side to the image side, including a first lens (601), a second lens (602), a third lens (603), an aperture (STOP), a fourth lens (604), a fifth lens (605), and a sixth lens (606).

[0869] In another embodiment, one or more of another lens, a flat plate, and an optical member may be added between the first lens (601) to the sixth lens (606). In addition, one or more of another lens, a flat plate, and an optical member may be added in front of the first lens (601) or behind the sixth lens (606). 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 (800), and between the filter (800) and the image sensor (700). In this case, the filter (800) 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 (800), and between the filter (800) and the image sensor (700). In this case, the filter layer may be coated to become a filter.

[0870] The first lens (601) may be arranged closest to the object side. The first lens (601) may be arranged farthest from the sensor side. The first lens (601) may have negative (-) refractive power on the optical axis (OA). The first lens (601) may include a plastic material or a glass material, and may be made of glass, for example. The first lens (601) made of glass may reduce changes in the center position and radius of curvature due to temperature changes in the surrounding environment, and may protect the incident side of the optical system (1500).

[0871] The first surface (S1) on the object side of the first lens (601) with respect to the optical axis may be convex, and the second surface (S2) on the sensor side may be concave. The first lens (601) may have a meniscus shape that is convex toward the object side. The first lens (601) 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.

[0872] Due to the refractive characteristics of the first lens (601), the second lens (602) can be further separated from the first lens (601). That is, the center spacing between the first and second lenses (601, 602) can be the largest within the lens unit.

[0873] The refractive index (n1) of the first lens (601) can satisfy the condition of n1 > 1.75 or n1 > 1.8. The radius of curvature of the first and second lenses (601, 602) can be increased, and lens manufacturing can be facilitated. If the refractive index (n1) of the first lens (601) 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 (601, 602). In this case, lens manufacturing is not easy, the lens defect rate increases, and it may cause a decrease in yield.

[0874]

[0875] The second lens (602) may be arranged second from the object side. The second lens (602) may be arranged fifth from the sensor side. The second lens (602) may be arranged between the first lens (601) and the third lens (603). The second lens (602) may have negative refractive power on the optical axis (OA). The second lens (602) may include a plastic or glass material. For example, the second lens (602) may be provided as a plastic material.

[0876] The object-side third surface (S3) of the second lens (602) with respect to the optical axis (OA) may be concave, and the sensor-side fourth surface (S4) may be concave. The second lens (602) may have a concave shape on both sides.

[0877] The second lens (602) may be made of plastic and may be aspherical. At least one or both of the third surface (S3) and the fourth surface (S4) may be aspherical. The aspherical coefficients of the third and fourth surfaces (S3, S4) may be provided as S1 and S2 of L2 in FIG. 46. 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.

[0878]

[0879] The third lens (603) may be arranged third from the object side. The third lens (603) may be arranged fourth from the sensor side. The third lens (603) may be arranged between the second lens (602) and the fourth lens (604). The third lens (603) may have positive (+) refractive power on the optical axis (OA). The third lens (603) may include a plastic or glass material. For example, the third lens (603) may be provided as a glass material.

[0880] The fifth surface (S5) on the object side of the third lens (603) with respect to the optical axis may be convex, and the sixth surface (S6) on the sensor side may be concave. The third lens (603) may have a meniscus shape with a convex object side. The third lens (603) may have a meniscus shape with a concave sensor side. The third lens (603) may be made of glass and may be spherical.

[0881] The aperture (Stop) may be arranged around the sensor-side sixth surface (S6) of the third lens (603). The aperture (Stop) may be arranged around the object-side seventh surface (S7) of the fourth lens (604). The aperture can reduce the TTL within the field of view range, enabling miniaturization of the optical system. Accordingly, a decrease in the yield by weight of the optical system can be prevented, and production efficiency can be improved. In addition, the optical system can be miniaturized by reducing the TTL within the horizontal field of view (FOV_H) of 130 to 150 degrees.

[0882] A field stop may be arranged between the third lens (603) and the fourth lens (604). The field stop may be formed so that the surface facing the optical axis of the spacer has a protruding shape or a sharp surface. The third lens (603) and the fourth lens (604) are lenses arranged in the central region of the optical system (1500), and may have smaller effective diameters than the first lens (601) arranged on the object side and the sixth lens (606) arranged on the sensor side. Therefore, in order to prevent ghosting due to diffuse reflection and to prevent the introduction of stray light, a field stop may be additionally arranged between the third lens (603) and the fourth lens (604).

[0883]

[0884] The fourth lens (604) may be arranged fourth from the object side. The fourth lens (604) may be arranged third from the sensor side. The fourth lens (604) may be arranged between the third lens (603) and the fifth lens (605). The fourth lens (604) may have positive (+) or negative (-) refractive power on the optical axis (OA). The fourth lens (604) may have positive (+) refractive power. The fourth lens (604) may include a plastic or glass material. For example, the fourth lens (604) may be provided as a plastic material.

[0885] The object-side seventh surface (S7) of the fourth lens (604) with respect to the optical axis may be convex, and the sensor-side eighth surface (S8) may be convex. The fourth lens (604) may have a convex shape on both sides. The fourth lens (604) 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. 46. 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.

[0886]

[0887] The fifth lens (605) may be arranged fifth from the object side. The fifth lens (605) may be arranged second from the sensor side. The fifth lens (605) may be arranged between the fourth lens (604) and the sixth lens (606). The fifth lens (605) may have positive (+) or negative (-) refractive power on the optical axis (OA). The fifth lens (605) may have negative (-) refractive power. The fifth lens (605) may include a plastic or glass material. For example, the fifth lens (605) may be provided with a plastic material.

[0888] With respect to the optical axis (OA), the ninth surface (S9) on the object side of the fifth lens (605) may be concave, and the tenth surface (S10) on the sensor side may be concave. The fifth lens (605) may have a concave shape on both sides. The fifth lens (605) may be made of a plastic material and may be aspherical. At least one or both of the ninth surface (S9) and the tenth surface (S10) may be aspherical. The aspherical coefficients of the ninth and tenth surfaces (S9, S10) may be provided as S1 and S2 of L5 in FIG. 46. 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.

[0889]

[0890] The fourth lens (604) and the fifth lens (605), which are joined lenses, can satisfy the following conditions.

[0891] Condition 1: Refractive index of lens with positive refractive power < refractive index of lens with negative refractive power

[0892] Condition 2: Dispersion of a lens with positive refractive power > Dispersion of a lens with negative refractive power

[0893] Here, among the plastic lenses, the fourth lens (604) has positive refractive power and the fifth lens (605) has negative refractive power, so that according to conditions 1 and 2, the refractive index of the fourth lens (604) is smaller than the refractive index of the fifth lens (605), and the dispersion value of the fourth lens (604) is larger than the dispersion value of the fifth lens (605). The chromatic aberration occurring in the plastic lens can be corrected by the plastic lens. In addition, since the fifth lens (605) and the fourth lens (604), which are plastic lenses arranged in succession, satisfy the refractive index difference of 0.1 or more and 0.15 or less and the 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.

[0894] 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 sixth embodiment of the present invention, chromatic aberration occurring in a plastic lens can be corrected by using the fourth lens (604) and the fifth lens (605).

[0895]

[0896] The sixth lens (606) may be positioned furthest from the object side. The sixth lens (606) may be positioned closest to the image sensor (700). The sixth lens (606) may have positive (+) or negative (-) refractive power on the optical axis (OA). The sixth lens (606) may have positive (+) refractive power. The sixth lens (606) may include a plastic or glass material. For example, the sixth lens (606) may be provided with a plastic material.

[0897] With respect to the optical axis (OA), the eleventh surface (S11) on the object side of the sixth lens (606) may be convex, and the twelfth surface (S12) on the sensor side may be concave. The sixth lens (606) may have a meniscus shape that is convex toward the object side. The sixth lens (606) may have a meniscus shape that is concave toward the sensor side. The sixth lens (606) 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 eleventh surface (S11) and the twelfth surface (S12) of the sixth lens (606) may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0898]

[0899] The sixth lens (606) may be a plastic lens closest to the image sensor (700). In addition, by arranging two or more plastic lenses adjacent to the image sensor (700), 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 (700), 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 (605, 606) adjacent to the image sensor (700) 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.

[0900]

[0901] LensSurfaceRadiusThicknessndvdSemiApertureFocal length1S112.7421.8001.80476.120-6.347S23.4272.8973.103 2S3-4.9481.1901.54562.845-7.253S419.8961.7852.250 3S531.3371.91301.8964.047S615.3120.9091.562 4S7(STOP)2.9350.9801.54560.9281.912S8-1.3960.0001.043 5S9-1.3960.4001.66201.043-1.769S108.5271.2841.100 6S113.9300.9911.67192.88110.692S127.6850.3562.883 FilterS13Infinity1.0002.889S14Infinity1.0342.974ImageInfinity0.0043.120

[0902] Example 6 Example 6 TTL 15.76 1 ET 12.20 80 F 2.5 14 ET 22.16 90 F no 2.39 5 ET 30.77 50 FOV_V 10 1.1 ET 40.40 60 FOV_H 140.0 ET 50.88 10 FOV_D 150.4 ET 60.38 50 EPD 1.04 9 Img H 6.100 BFL 2.60 4 SD (Stop~L6S2) 4.45 TD (L1S1~L6S2) 13.55

[0903] Tables 16 and 17 show the characteristics of the optical system according to the sixth embodiment of the present invention. Descriptions of the parameters included in Tables 16 and 17 are omitted as they overlap with those of the first embodiment of the present invention.

[0904]

[0905] The center thicknesses of the first to sixth lenses (601 to 606) are represented by CT1 to CT6, the edge thicknesses at the ends of the effective areas of each lens are represented by ET1 to ET6, the center gap between two adjacent lenses is represented by CG1 to CG5, and the edge gaps between the edges of each lens are represented by EG1 to EG5. The BFL (Back focal length) is the optical axis distance from the image sensor (700) 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 (601) to the upper surface of the image sensor (700).

[0906] As shown in Fig. 46, among the lenses of the lens unit of the sixth embodiment, the lens surfaces of the second, fourth, fifth, and sixth lenses (602, 604, 605, and 606) may include aspherical surfaces having a 30th-order aspherical surface coefficient. For example, the second, fourth, fifth, and sixth lenses (602, 604, 605, and 606) 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).

[0907] When comparing the absolute values ​​of the curvature radii of each lens, the curvature radii of the fourth surface (S4) of the second lens (602) on the optical axis (OA) may be the largest among the lenses, and the curvature radii of the eighth surface (S8) of the fourth lens (604) and the ninth surface (S9) of the fifth lens (605) may be the smallest among the lenses. The difference between the maximum curvature radii and the minimum curvature radii may be 13 times or more, for example, 15 times to 20 times.

[0908] 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.

[0909] The absolute value of the curvature radius of the first surface (S1) of the first lens (601) 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 (602) 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 (603) may be less 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 (604) 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 (605) may be less than the absolute value of the curvature radius of the tenth surface (S10). The absolute value of the radius of curvature of the eleventh surface (S11) of the sixth lens (606) may be smaller than the absolute value of the radius of curvature of the twelfth surface (S12).

[0910] The ratio of the radius of curvature of each lens can satisfy the following conditions.

[0911] Condition 1: 3 < |L1R1 / L1R2| < 5

[0912] Condition 2: 0.1 < |L2R1 / L2R2| < 0.5

[0913] Condition 3: 0.1 < |L3R1 / L3R2| < 0.5

[0914] Condition 4: 1 < |L4R1 / L4R2| < 5

[0915] Condition 5: 0.1 < |L5R1 / L5R2| < 0.5

[0916] Condition 6: 0.3 < |L6R1 / L6R2| < 0.8

[0917]

[0918] When describing the central thickness (CT) of the lenses based on the optical axis, the central thickness (CT1) of the first lens (601) is the largest among the lenses, and the central thickness (CT5) of the fifth lens (605) 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.

[0919] The central thickness of each lens may satisfy any one of the following conditions:

[0920] Condition 1: CT1 > CT2, CT3, CT4, CT5, CT6

[0921] Condition 2: CT1, CT3, CT4, CT6 > CT2 > CT5

[0922] Condition 3: CT1, CT4, CT6 > CT3 > CT2, CT5

[0923] Condition 4: CT1, CT6 > CT4 > CT2, CT3, CT5,

[0924] Condition 5: CT1, CT2, CT3, CT4, CT6 > CT5

[0925] Condition 6: CT1 > CT6 > CT2, CT3, CT4, CT5

[0926]

[0927] When describing the center spacing (CG) between the lenses, the center spacing (CG1) between the first lens (601) and the second lens (602) may be the maximum, and the center spacing (CG3) between the third and fourth lenses (603, 604) may be the minimum. The difference between the maximum center spacing and the minimum center spacing among the spaced lens spacings may be 1.5 mm or more, for example, in the range of 1.6 mm to 2 mm.

[0928] The center spacing between each lens can satisfy the conditions below.

[0929] Condition 1: CG1 > CG2, CG3, CG5

[0930] Condition 2: CG1 > CG2 > CG3, CG5

[0931] Condition 3: CG1, CG2, CG5 > CG3

[0932] Condition 4: CG1, CG2, CG5 > CG3

[0933]

[0934] 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 (601). 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 (601).

[0935] The lens having the minimum effective diameter may be a lens arranged between the aperture (STOP) and the sixth lens (606). The lens having the minimum effective diameter may be the fourth lens (604). The lens surfaces having the minimum effective diameter may be the eighth surface (S8) of the fourth lens (604) and the ninth surface (S9) of the fifth lens (605). The effective diameter of the lens made of plastic may be smaller than that of the lens made of glass. The lens made of plastic may be arranged adjacent to the image sensor.

[0936] The effective diameter of each lens can satisfy any one of the conditions below.

[0937] Condition 1: CA_L1 > CA_L2, CA_L3, CA_L4, CA_L5, CA_L6

[0938] Condition 2: CA_L1, CA_L6 > CA_L2 > CA_L3, CA_L4, CA_L5

[0939] Condition 3: CA_L1, CA_L2, CA_L6 > CA_L3 > CA_L4, CA_L5

[0940] Condition 4: CA_L1, CA_L2, CA_L3, CA_L5, CA_L6 > CA_L4

[0941] Condition 5: CA_L1, CA_L2, CA_L3, CA_L6 > CA_L5 > CA_L4

[0942] Condition 6: CA_L1 > CA_L6 > CA_L2, CA_L3, CA_L4, CA_L5

[0943]

[0944] In terms of refractive index, the refractive index of the third lens (603) may be the largest among the lenses and may be greater than 1.85, for example, greater than 1.9. Either or both of the second lens (602) and the fourth lens (604) may have the smallest refractive index among the lenses. For example, the refractive index of the second lens (602) and the fourth lens (604) 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 (700) 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 (700).

[0945] The refractive index of each lens can satisfy any of the conditions below.

[0946] Condition 1: n3 > n1 > n2, n4, n5, n6

[0947] Condition 2: n1, n3, n5, n6 > n2 = n4

[0948] Condition 3: n3 > n1, n2, n4, n5, n6

[0949] Condition 4: n1, n2, n3, n4 > n5 > n6

[0950] Condition 5: n1, n3 > n6 > n2, n4, n5

[0951]

[0952] Comparing the Abbe numbers, the Abbe number of at least one of the second lens (602) and the fourth lens (604) is the largest among the lenses and may be 53 or more. The Abbe number of the sixth lens (606) 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 fourth lens (604) arranged at the center of the optical system (1500) to be the largest and the Abbe number of the sixth lens (606) having a low refractive index adjacent to the image sensor (700) 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 (700).

[0953] The Abbe number of each lens can satisfy any of the conditions below.

[0954] Condition 1: v5, v6 > v1 > v2, v3, v4

[0955] Condition 2: v2 = v4 > v1, v3, v5, v6

[0956] Condition 3: v1, v2, v4 > v3 > v5, v6

[0957] Condition 4: v1, v2, v3, v4 > v5 > v6

[0958] Condition 5: v1, v2, v3, v4, v5 > v6

[0959]

[0960] The focal lengths (F1, F2, F5) of the first, second, and fifth lenses (601, 602, and 605) may have negative (-) signs. The first, second, and fifth lenses (601, 602, and 605) may have negative (-) refractive power. The focal lengths (F3, F4, and F6) of the third, fourth, and sixth lenses (603, 604, and 606) may have positive (+) signs. The third, fourth, and sixth lenses (603, 604, and 606) may have positive (+) refractive power.

[0961] When comparing the focal lengths in absolute values, the focal length of the sixth lens (606) is the largest among the lenses, and may be 10 or more and 20 or less. The focal length of the fifth lens (605) is the smallest among the lenses, and the absolute value of the focal length of the fifth lens (605) may be 1 or more and 3 or less.

[0962] The absolute value of the focal length of each lens can satisfy any of the conditions below.

[0963] Condition 1: |f2|, |f6| > |f1| > |f3|, |f4|, |f5|

[0964] Condition 2: |f6| > |f2| > |f1|, |f3|, |f4|, |f5|

[0965] Condition 3: |f1|, |f2|, |f6| > |f3| > |f4|, |f5|

[0966] Condition 4: |f1|, |f2|, |f3|, |f6| > |f4| > |f5|

[0967] Condition 5: |f1|, |f2|, |f3|, |f4|, |f6| > |f5|

[0968] Condition 6: |f6| > |f1|, |f2|, |f3|, |f4|, |f5|

[0969]

[0970] Any one of the fourth to sixth lenses (604-606) made of a plastic material and arranged adjacent to the sensor side may have a different refractive power from the other two. For example, the fourth and sixth lenses (604, 606) may have a negative (-) refractive power, and the fifth lens (606) may have a positive (+) refractive power. The absolute value of the focal length of one lens having a different refractive power from the other two among the fourth to sixth lenses (604-606) may be smaller than the absolute values ​​of the focal lengths of the other two. The refractive power of one lens having a different refractive power from the other two among the fourth to sixth lenses (604-606) may be larger than the refractive powers of the other two. For example, the absolute value of the focal length of the fifth lens (605) having a positive (+) refractive power may be smaller than the focal lengths of the fourth and sixth lenses (604, 606) having a negative (-) refractive power.

[0971] Since the plastic lens disposed adjacent to the image sensor (700) is sensitive to temperature changes, the composite refractive power of the plastic lens can be designed to be close to 0. In other words, the composite refractive power of the plastic lens disposed adjacent to the image sensor (700) can be reduced. Through this, the refractive power of the plastic lens, which is sensitive to temperature changes, can be offset within the plastic lens, thereby minimizing changes in the performance of the overall optical system, and minimizing the influence of the plastic lens on the optical performance of the overall optical system (1500).

[0972] The ratio of the absolute values ​​of the focal lengths of the glass lenses included in the optical system (1500) can satisfy a value of 0.8 or more and 1.2 or less. For example, the absolute value (|f1| / |f3|) of the ratio of the focal lengths of the first lens (601) and the third lens (603) made of glass can satisfy a value of 0.8 or more and 1.2 or less. In addition, the signs of the focal lengths of the first lens (601) and the third lens (603) made of glass can be different from each other. Through this, the overall refractive power of the optical system (1500) can be greatly affected by the glass lens that is strong against temperature changes.

[0973]

[0974] The thickness (T1) of the first lens (601) may be a difference of at least 1 time between the maximum thickness and the minimum thickness, for example, 1 to 1.5 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 (602) may be a maximum thickness in a range of 1.5 to 2 times the minimum thickness. The second lens (602) may be a minimum in the center thickness (CT2) and the maximum in the edge thickness (ET2). The thickness (T3) of the third lens (603) may be a maximum in the center and a minimum in 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 (604) may be a maximum in the center and a minimum in the edge, and the maximum thickness is a range of 2 to 2.5 times the minimum thickness. The thickness (T5) of the fifth lens (605) may be minimum at the center and maximum at the edge, and the maximum thickness is in the range of 2 to 2.5 times the minimum thickness. The thickness (T6) of the sixth lens (606) may be maximum at the center and minimum at the edge, and the maximum thickness is in the range of 2.3 to 2.8 times the minimum thickness.

[0975] 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.

[0976] The thickness of each lens can satisfy any of the conditions below.

[0977] Condition 1: 0.5 < CT1 / ET1 < 1, 1 < ET1 / CT1 < 1.5

[0978] Condition 2: 0.3 < CT2 / ET2 < 0.8, 1.5 < ET2 / CT2 < 2

[0979] Condition 3: 1.5 < CT3 / ET3 < 2, 0.3 < ET3 / CT3 < 0.8

[0980] Condition 4: 2 < CT4 / ET4 < 2.5, 0.1 < ET4 / CT4 < 0.5

[0981] Condition 5: 0.1 < CT5 / ET5 < 0.5, 2 < ET5 / CT5 < 2.5

[0982] Condition 6: 2.3 < CT6 / ET6 < 2.8, 0.1 < ET6 / CT6 < 0.5

[0983] Condition 7: 0.5 < ΣCT / ΣET < 1, 1 < ΣET / ΣCT < 1.5

[0984]

[0985] Among the gaps (G1-G7) between the lenses, the first gap (G1) between the first and second lenses (601, 602) may have a maximum in the center and a minimum in the edge. The second gap (G2) between the second and third lenses (602, 603) may have a minimum in the center and a maximum in the edge. The third gap (G3) between the third and fourth lenses (603, 604) may have a maximum in the edge and a minimum in the center. The fifth gap (G5) between the fifth and sixth lenses (605, 606) may have a minimum in the center and a maximum in the edge.

[0986] The optical systems (1000, 1100, 1200, 1300, 1400, 1500) according to the first to sixth 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, 1300, 1400, 1500) according to the first to sixth embodiments can have improved optical characteristics. For example, when the optical systems (1000, 1100, 1200, 1300, 1400, 1500) satisfy at least one mathematical equation, the optical systems (1000, 1100, 1200, 1300, 1400, 1500) 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 system (1000, 1100, 1200, 1300, 1400, 1500) 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 can refer to the first to sixth embodiments disclosed above.

[0987]

[0988] [Mathematical Formula 1]

[0989] 0.1 < F / TTL < 0.3

[0990] In mathematical expression 1, F is the effective focal length of the optical system, and TTL (Total track length) means the distance (mm) on the optical axis (OA) from the vertex of the first surface (S1) of the first lens (101, 201, 301, 401, 501, 601) to the upper surface of the image sensor (300). Accordingly, an optical system for a driver assistance system can be provided. When the optical system (1000, 1100, 1200, 1300, 1400, 1500) according to the embodiment satisfies mathematical expression 1, the optical system (1000, 1100, 1200, 1300, 1400, 1500) can have an appropriate focal length in the set TTL range, and provides an optical system that can form an image while maintaining an appropriate focal length even when the temperature changes from low temperature to high temperature. If it is below the lower limit of mathematical expression 1, the refractive power of the lenses needs to be increased, making it difficult to correct spherical aberration or distortion aberration. If it is above the upper limit of mathematical expression 1, 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 sixth embodiments, mathematical expression 1 may preferably satisfy 0.13 < F / TTL < 0.2.

[0991]

[0992] [Equation 2]

[0993] 2 < TTL / ImgH < 3

[0994] Mathematical expression 2 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, 401, 501, 601) to the upper surface of the image sensor (300) on the optical axis (OA), and ImgH means the maximum diagonal length of the image sensor (300). When Mathematical expression 2 is satisfied, the optical system (1000, 1100, 1200, 1300, 1400, 1500) can have TTL for application to the vehicle image sensor (300), thereby providing improved image quality. If it is below the lower limit of mathematical expression 2, the refractive power of the lenses needs to be increased, making it difficult to correct spherical aberration or distortion aberration. If it is above the upper limit of mathematical expression 2, 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 sixth embodiments, mathematical expression 2 may preferably satisfy 2 < TTL / ImgH < 2.8.

[0995]

[0996] [Equation 3]

[0997] 1 < |F1| / F < 3

[0998] In mathematical expression 3, F1 is the focal length of the first lens (101, 201, 301, 401, 501, 601), and F is the effective focal length of the optical system. When mathematical expression 3 is satisfied, the optical system (1000, 1100, 1200, 1300, 1400, 1500) can have a set angle of view and an appropriate focal length, and a vehicle optical system can be provided. In addition, the angle of view can be set to be large within an appropriate TTL range through the first lens (101, 201, 301, 401, 501, 601) having negative (-) refractive power. When it is less than the lower limit of mathematical expression 3, the effective diameter or TTL of the lenses may become long, which may cause a problem of the imaging lens system becoming large. If the upper limit of mathematical expression 3 is exceeded, the influence of the first lens (101, 201, 301, 401, 501, 601) becomes small in the entire optical system, and the refractive power of the lenses needs to be increased, which causes a problem in that correction of spherical aberration or distortion aberration becomes difficult. In the first to sixth embodiments, mathematical expression 3 can preferably satisfy 1.3 < |F1| / F < 2.7.

[0999]

[1000] [Equation 4]

[1001] 2 < F2 / F < 7

[1002] In mathematical expression 4, F2 is the focal length of the second lens (102, 202, 302, 402, 502, 602), and F is the effective focal length of the optical system. When mathematical expression 4 is satisfied, the optical system (1000, 1100, 1200, 1300, 1400, 1500) can have a set angle of view and an appropriate focal length, and a vehicle optical system can be provided. When it is below the lower limit of mathematical expression 4, the effective diameter or TTL of the lenses may become long, which may cause a problem in that the imaging lens system becomes large. When it is above the upper limit of mathematical expression 4, the influence of the second lens (102, 202, 302, 402, 502, 602) becomes small in the entire optical system, and the refractive power of the lenses needs to be increased, which causes a problem in that it is difficult to correct spherical aberration or distortion aberration. In the first to sixth embodiments, mathematical expression 4 can preferably satisfy 2.5 < F2 / F < 6.9.

[1003]

[1004] [Equation 5]

[1005] L2R1 < 0

[1006] In mathematical expression 5, L2R1 is the radius of curvature of the object-side surface (third surface (S3)) of the second lens (102, 202, 302, 402, 502, 602). When mathematical expression 5 is satisfied, the gap between the first lens (101, 201, 301, 401, 501, 601) and the second lens (102, 202, 302, 402, 502, 602) can be secured during lens assembly, facilitating assembly. In addition, when mathematical expression 5 is satisfied, the influence on incident light and TTL can be controlled.

[1007]

[1008] [Equation 6]

[1009] 1 < F3 / F < 2

[1010] In mathematical expression 6, F3 is the focal length of the third lens (103, 203, 303, 403, 503, 603), and F is the effective focal length of the optical system. When mathematical expression 6 is satisfied, the optical system (1000, 1100, 1200, 1300, 1400, 1500) 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 third lens (103, 203, 303, 403, 503, 603) made of glass can minimize changes in optical characteristics due to temperature changes of the entire optical system. In the first to sixth embodiments, mathematical expression 6 can preferably satisfy 1.5 < F3 / F < 2.

[1011]

[1012] [Equation 7]

[1013] 0.1 < |F4| / F < 2

[1014] In mathematical expression 7, F4 is the focal length of the fourth lens (104, 204, 304, 404, 504, 604), and F is the effective focal length of the optical system. When mathematical expression 7 is satisfied, aberration characteristics can be secured, and a stable optical system can be formed by forming a gentle optical path at a short TTL. When it is below the lower limit of mathematical expression 7, the effective diameter or TTL of the lenses may become long, which may cause a problem of the large size of the imaging lens system. When it is above the upper limit of mathematical expression 7, the influence of the fourth lens (104, 204, 304, 404, 504, 604) in the entire optical system becomes small, and the refractive power of the lenses needs to be increased, which causes a problem of difficulty in correcting spherical aberration or distortion aberration. In the first to fourth embodiments, mathematical expression 7 can preferably satisfy 0.5 < |F4| / F < 1.8.

[1015]

[1016] [Equation 8]

[1017] 1.5 < n4 < 1.7

[1018] In mathematical expression 8, n4 is the refractive index of the fourth lens (104, 204, 304, 404, 504, 604). When mathematical expression 8 is satisfied, the fourth lens (104, 204, 304, 404, 504, 604) can minimize chromatic aberration by having a high refractive index among plastic lenses. In the first to sixth embodiments, mathematical expression 8 can preferably satisfy 1.52 < n4 < 1.68.

[1019]

[1020] [Equation 9]

[1021] 0.1 < |F5| / F < 3

[1022] In mathematical expression 9, F5 is the focal length of the fifth lens (105, 205, 305, 405, 505, 605), and F is the effective focal length of the optical system. When mathematical expression 9 is satisfied, aberration characteristics can be secured, and a stable optical system can be formed by forming a gentle optical path at a short TTL. When it is below the lower limit of mathematical expression 9, the effective diameter or TTL of the lenses may become long, which may cause a problem of the large size of the imaging lens system. When it is above the upper limit of mathematical expression 9, the influence of the fifth lens (105, 205, 305, 405, 505, 605) in the entire optical system becomes small, and the refractive power of the lenses needs to be increased, which causes a problem of difficulty in correcting spherical aberration or distortion aberration. In the first to fourth embodiments, mathematical expression 9 can preferably satisfy 1.2 < |F5| / F < 2.5. In the fifth and sixth embodiments, mathematical expression 9 can preferably satisfy 0.5 < |F5| / F < 1.

[1023]

[1024] [Equation 10]

[1025] 1.5 < n5 < 1.7

[1026] In mathematical expression 10, n5 is the refractive index of the fifth lens (105, 205, 305, 405, 505, 605). When mathematical expression 10 is satisfied, the fifth lens (105, 205, 305, 405, 505, 605) can minimize chromatic aberration by having a high refractive index among plastic lenses. In the first to sixth embodiments, mathematical expression 10 can preferably satisfy 1.52 < n5 < 1.68.

[1027]

[1028] [Equation 11]

[1029] 3 < |F6| / F < 50

[1030] In mathematical expression 11, F6 is the focal length of the sixth lens (106, 206, 306, 406, 506, 606), and F is the effective focal length of the optical system. When mathematical expression 11 is satisfied, the optical system (1000, 1100, 1200, 1300, 1400, 1500) can have a set angle of view and an appropriate focal length, and a vehicle optical system can be provided. When it is below the lower limit of mathematical expression 11, the effective diameter or TTL of the lenses may become long, which may cause a problem in that the imaging lens system becomes large. When it is above the upper limit of mathematical expression 11, the influence of the sixth lens (106, 206, 306, 406, 506, 606) becomes small in the entire optical system, and the refractive power of the lenses needs to be increased, which causes a problem in that it is difficult to correct spherical aberration or distortion aberration. In the first and second embodiments, mathematical expression 11 can preferably satisfy 10 < |F6| / F < 45. In the third to sixth embodiments, mathematical expression 11 can preferably satisfy 3 < |F6| / F < 5.

[1031]

[1032] [Equation 12]

[1033] 2 < CA_L1S1 / F < 5

[1034] In mathematical expression 12, CA_L1S1 is the effective diameter of the object-side surface (first surface (S1)) of the first lens (101, 201, 301, 401, 501, 601), and F is the effective focal length of the optical system. If it is less than the lower limit of mathematical expression 12, the effective diameter of the lens arranged in the optical system (1000, 1100, 1200, 1300, 1400, 1500) becomes the largest, which causes a problem in that the TTL becomes longer. If it exceeds the upper limit of mathematical expression 12, there is a problem in that the angle of view becomes excessively larger than that satisfied by the optical system (1000, 1100, 1200, 1300, 1400, 1500). In the first to sixth embodiments, mathematical expression 12 can preferably satisfy 3 < CA_L1S1 / F < 5.

[1035]

[1036] [Equation 13]

[1037] 1 < F / EPD < 3

[1038] In mathematical expression 13, F represents the effective focal length of the optical system, and EPD represents the diameter of the entrance pupil (effective aperture). When mathematical expression 13 is satisfied, an image with a brightness suitable for driver monitoring can be provided, and a large amount of light can be received by the image sensor. In the first to sixth embodiments, mathematical expression 13 preferably satisfies 1.5 < F / EPD < 2.5.

[1039]

[1040] [Equation 14]

[1041] 0.1 < BFL / TTL < 0.5

[1042] In mathematical expression 14, BFL means the optical axis distance from the image sensor (300) to the center of the sensor side of the last lens, and TTL (Total track length) means the distance (mm) on the optical axis (OA) from the vertex of the first surface (S1) of the first lens (101, 201, 301, 401, 501, 601) to the upper surface of the image sensor (300). When mathematical expression 14 is satisfied, the optical system (1000, 1100, 1200, 1300, 1400, 1500) 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, 1300, 1400, 1500) can minimize the gap between the last lens and the image sensor (300), and thus can have good optical characteristics at the periphery of the field of view (FOV). In the first to sixth embodiments, mathematical expression 14 can preferably satisfy 0.1 < BFL / TTL < 0.2.

[1043]

[1044] [Equation 15]

[1045] 0.1 < CT5 / F < 2

[1046] In mathematical expression 15, CT5 is the central thickness of the fifth lens (105, 205, 305, 405, 505, 605), and F is the effective focal length of the optical system. When mathematical expression 15 is satisfied, the entire optical system (1000, 15000) can have a short focal length within an appropriate TTL. In the first to sixth embodiments, mathematical expression 15 can preferably satisfy 0.1 < CT5 / F < 1.3.

[1047]

[1048] [Equation 16]

[1049] 0.1 < CT_Max / CG_Max < 2

[1050] In mathematical expression 16, CT_Max is the maximum central thickness among the lenses, and CG_Max is the maximum gap between adjacent lenses. When mathematical expression 16 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 sixth embodiments, mathematical expression 16 can preferably satisfy 0.5 < CT_Max / CG_Max < 1.5.

[1051]

[1052] [Equation 17]

[1053] 2 < CA_max / CA_min < 5

[1054] In mathematical expression 17, 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 17 is satisfied, the optical system can set a size for a slim and compact structure while maintaining optical performance. In the first to sixth embodiments, mathematical expression 17 can preferably satisfy 2.5 < CA_max / CA_min < 4.8.

[1055]

[1056] [Equation 18]

[1057] 0.1 < ΣCG / ΣCT < 1.5

[1058] In mathematical expression 18, 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 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 sixth embodiments, mathematical expression 18 can preferably satisfy 0.3 < ΣCG / ΣCT < 1.2.

[1059]

[1060] [Equation 19]

[1061] 0.1 < CG1 / ΣCG < 1

[1062] In mathematical expression 19, CG1 is the center spacing between the first lens (101, 201, 301, 401, 501, 601) and the second lens (102, 202, 302, 402, 502, 602), and ΣCG is the sum of the spacings between adjacent lenses. When mathematical expression 19 is satisfied, the light emitted from the first lens (101, 201, 301, 401, 501, 601), 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 sixth embodiments, mathematical expression 19 can preferably satisfy 0.3 < CG1 / ΣCG < 0.8.

[1063]

[1064] [Equation 20]

[1065] 0.1 < CG1 / ΣCT < 0.5

[1066] In mathematical expression 20, CG1 is the center spacing between the first lens (101, 201, 301, 401, 501, 601) and the second lens (102, 202, 302, 402, 502, 602), and ΣCT is the sum of the center thicknesses of the lenses. When mathematical expression 20 is satisfied, the light emitted from the first lens (101, 201, 301, 401, 501, 601), 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 sixth embodiments, mathematical expression 20 can preferably satisfy 0.2 < CG1 / ΣCT < 0.5.

[1067]

[1068] [Equation 21]

[1069] 130 < FOV_H < 160

[1070] In mathematical expression 21, FOV_H represents the horizontal angle of view (Degree) of the optical system (1000, 1100, 1200, 1300, 1400, 1500), and can provide an angle of view suitable for a vehicle optical system. In the first to sixth embodiments, preferably, 135 < FOV_H < 155 can be satisfied.

[1071]

[1072] [Equation 22]

[1073] 1 < TTL / CA_max < 3

[1074] In mathematical expression 22, TTL (Total track length) means the distance (mm) from the vertex of the first surface (S1) of the first lens (101, 201, 301, 401, 501, 601) to the upper surface of the image sensor (300) on the optical axis (OA), and CA_max represents the maximum effective diameter among the object-side surfaces and the sensor-side surfaces of the lenses. When mathematical expression 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 sixth embodiments, mathematical expression 22 can preferably satisfy 1.5 < TTL / CA_max < 2.5.

[1075]

[1076] [Equation 23]

[1077] 10 < TTL < 20

[1078] 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, 401, 501, 601) to the upper surface of the image sensor (300) on the optical axis (OA). When mathematical expression 23 is satisfied, a suitable vehicle optical system can be provided. In the first to sixth embodiments, mathematical expression 23 can preferably satisfy 12 < TTL < 17.

[1079]

[1080] [Equation 24]

[1081] 6 < ImgH < 7

[1082] Mathematical expression 24 indicates that ImgH represents the maximum diagonal length of the image sensor (300). Mathematical expression 24 can set the diagonal size of the image sensor (300) and provide an optical system having a vehicle sensor size. In the first to sixth embodiments, Mathematical expression 24 preferably satisfies 6 < ImgH < 6.7.

[1083]

[1084] [Equation 25]

[1085] 1 < BFL < 3

[1086] In mathematical expression 25, BFL is the optical axis distance from the image sensor (300) to the center of the sensor side of the last lens. When mathematical expression 25 is satisfied, the installation space of the filter (400) and the cover glass can be secured, the assembling of the components can be improved through the gap between the image sensor (300) and the last lens, and the bonding reliability can be improved. When BFL is less than the range of mathematical expression 25, some of the light traveling to the image sensor cannot be transmitted to the image sensor, which may cause a decrease in resolution. When BFL exceeds the range of mathematical expression 25, stray light may be introduced, which may deteriorate the aberration characteristics of the optical system. In the first to sixth embodiments, mathematical expression 25 may preferably satisfy 1.5 < BFL < 2.5.

[1087]

[1088] [Equation 26]

[1089] 2 < F < 3

[1090] Mathematical expression 26 can set the overall focal length (F) to suit the vehicle optical system. In the first to sixth embodiments, Mathematical expression 26 can satisfy 2.1 < F < 2.8.

[1091]

[1092] [Equation 27]

[1093]

[1094] In mathematical expression 27, 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.

[1095]

[1096] The optical systems (1000, 1100, 1200, 1300, 1400, 1500) according to the first to sixth embodiments can satisfy at least one or two or more mathematical expressions from mathematical expressions 1 to 26. In this case, the optical systems (1000, 1100, 1200, 1300, 1400, 1500) can have improved optical characteristics. In detail, when the optical systems (1000, 1100, 1200, 1300, 1400, 1500) satisfy at least one or two or more mathematical expressions from mathematical expressions 1 to 26, the optical systems (1000, 1100, 1200, 1300, 1400, 1500) can have improved resolution and improve aberration and distortion characteristics. In addition, the optical system (1000, 1100, 1200, 1300, 1400, 1500) can secure a BFL (Back focal length) for applying a vehicle image sensor (300), can compensate for the deterioration of optical characteristics due to temperature change, and can minimize the gap between the last lens and the image sensor (300), thereby providing good optical performance in the center and periphery of the field of view (FOV).

[1097]

[1098] Table 18 shows the result values ​​for the mathematical expressions 1 to 26 described above in the optical system (1000, 1100, 1200, 1300, 1400, 1500) of the embodiment. Referring to Table 18, it can be seen that the optical system (1000, 1100, 1200, 1300, 1400, 1500) satisfies at least one, two or more, or three or more of the mathematical expressions 1 to 26. In detail, it can be seen that the optical system (1000, 1100, 1200, 1300, 1400, 1500) according to the embodiment satisfies all of the mathematical expressions 1 to 26. Accordingly, the optical system (1000, 1100, 1200, 1300, 1400, 1500) can have good optical performance and excellent optical characteristics in the center and periphery of the field of view (FOV).

[1099]

[1100] Mathematical formulaExample 1Example 2Example 3Example 4Example 5Example 6Example 100.1 < F / TTL < 0.30.200.160.150.150.160.1622 < TTL / ImgH < 32.082.642.122.132.5842.58431 < |F1| / F < 31.581.811.872.142.2822.52542 < F2 / F < 73.166.884.975.464.0742.8855L2R1 < 0-8.71-6.56-11.45-8.88-3.061-4.94861 < F3 / F < 21.571.931.751.811.7111.6171 < |F4| / F < 21.231.471.711.70.7740.76181.5 < n4 < 1.71.671.671.671.671.541.5491 < |F5| / F < 32.111.431.411.430.7420.704101.5 < n5 < 1.61.541.541.541.541.641.661110 < |F6| / F < 5012.66244.3173.2113.4424.6854.253122 < CA_L1S1 / F < 43.0113.3474.264.1794.1984.869131 < F / EPD < 32.1961.9962.3982.3982.3972.397140.1 < BFL / TTL < 0.20.1463230.152770.1430.1420.140.14150.1 < CT5 / F < 10.3770.5721.1991.0660.340.159161 < CT_Max / CG_Max < 21.3671.2041.3361.1480.8360.621172 < CA_max / CA_min < 42.8562.5363.1013.064.1754.679180.3 < ΣCG / ΣCT < 0.80.51390.5150.3370.4370.6071.026190.1 < CG1 / ΣCG < 10.5240.4500.6330.5890.5820.421200.1 < CG1 / ΣCT < 0.50.2690.2320.2130.2580.3530.43321130 < FOV_H <1501401>40150.3150.3140140221 < TTL / CA_max < 32.1472.3632.0792.0421.9561.7092310 < TTL < 2013.0015.99314.01914.13515.76115.761246 < ImgH < 76.2456.0656.6086.6286.16.1251 < BFL < 31.9022.4432.0072.0152.2042.204262 < F < 32.5602.6282.1382.1572.5142.514.

[1101] Fig. 48 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. 48, 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 ima...

Claims

1. In order from the object side to the sensor side, First lens; A second lens having positive (+) refractive power; Third lens; 4th lens; Fifth lens; and Includes the sixth lens, The signs of the refractive powers of the first and second lenses are different from each other, An optical system in which the sign of the refractive power of any one of the fourth to sixth lenses is different from the signs of the refractive power of the other two lenses.

2. In paragraph 1, An optical system in which the absolute value of the focal length of the fourth to sixth lenses, the sign of the refractive power of which is different from that of the remaining two lenses, is smaller than the absolute value of the focal length of the remaining two lenses.

3. In paragraph 1, The above second lens has a convex meniscus shape toward the sensor, The above third lens is an optical system having a biconvex shape.

4. In paragraph 1, An optical system in which the absolute value of the focal length of the sixth lens is the largest among the absolute values ​​of the focal lengths of the first to sixth lenses.

5. In paragraph 1, An optical system in which the distance between the first lens and the second lens is the greatest among the distances between adjacent lenses on the optical axis.

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

7. In paragraph 1, The first and third lenses are made of glass, The above fourth to sixth lenses are optical systems made of plastic.

8. In paragraph 1, An optical system in which the central thickness of the fourth lens is the smallest among the central thicknesses of the first to sixth lenses on the optical axis.

9. In paragraph 1, An optical system in which the refractive index of the first lens is the greatest among the refractive indices of the first to sixth lenses.

10. In any one of paragraphs 1 to 9, An optical system that satisfies the following conditions. <Conditional expression> 130 < FOV_H < 150 (In the above conditional expression, FOV_H means the horizontal angle of view of the optical system.)

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