Optical system and camera module

Abstract

An optical system, according to one embodiment of the present invention, comprises first to eighth lenses arranged along an optical axis, wherein the fifth lens has negative (-) refractive power, the sixth lens has positive (+) refractive power, the seventh lens has positive (+) refractive power, the eighth lens has negative (-) refractive power, and the sign of the radius of curvature on the sensor-side surface of the second lens is the same as the sign of the radius of curvature on the object-side surface of the third lens.

Description

Optical system and camera module

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

[0002] Recently, research has been focused on image pickup systems (IPS), including camera modules for communication terminals, digital still cameras (DSCs), camcorders, and PC cameras (image capture devices attached to personal computers). One of the most crucial components for camera modules in these IPS systems to capture images is the imaging lens, which forms the image.

[0003] Portable devices, such as mobile phones and car cameras, are increasingly becoming smaller and / or lighter. In line with this trend, imaging lenses are also becoming smaller. Furthermore, along with smaller imaging lenses, the increasing performance of photodetectors is driving the demand for higher-performance imaging lenses.

[0004] The present invention seeks to provide a photographic lens capable of wide-angle photography.

[0005] Additionally, we aim to provide a compact imaging lens suitable for high resolution.

[0006] In addition, it is intended to provide an imaging lens having excellent aberration characteristics and good aberration correction capability.

[0007] In order to solve the above technical problem, an optical system according to an embodiment of the present invention includes first to eighth lenses arranged along an optical axis, wherein the fifth lens has negative (-) refractive power, the sixth lens has positive (+) refractive power, the seventh lens has positive (+) refractive power, and the eighth lens has negative (-) refractive power, and the sign of the curvature radius of the sensor-side surface of the second lens and the sign of the curvature radius of the object-side surface of the third lens are the same.

[0008] Among the first to eighth lenses on the optical axis, the thickness of the second lens may be the smallest.

[0009] Among the distances between adjacent lenses on the optical axis, the distance between the first lens and the second lens may be the smallest.

[0010] An aperture may be placed between the second lens and the third lens.

[0011] Among the distances between adjacent lenses on the optical axis, the distance between the seventh lens and the eighth lens may be the greatest.

[0012] Among the first to eighth lenses on the optical axis, the thickness of the first lens may be the largest.

[0013] The following condition can be satisfied. <Condition> 8 < TTL < 9.5 (In the above condition, TTL means the distance from the object side of the first lens to the upper surface of the image sensor on the optical axis.)

[0014] The following condition can be satisfied. <Condition> 2 < L2R2 / L3R1 < 3 (In the above condition, L2R2 is the radius of curvature of the sensor side of the second lens, and L3R1 is the radius of curvature of the object side of the third lens.)

[0015] In order to solve the above technical problem, an optical system according to another embodiment of the present invention includes first to eighth lenses arranged along an optical axis, wherein the fifth lens has negative (-) refractive power, the sixth lens has positive (+) refractive power, the seventh lens has positive (+) refractive power, and the eighth lens has negative (-) refractive power, and a thickness of the sixth lens on the optical axis is greater than a thickness of the seventh lens.

[0016] Among the first to eighth lenses on the optical axis, the thickness of the third lens may be the smallest.

[0017] The object-side surface of the second lens on the optical axis may be concave, and the sensor-side surface of the third lens on the optical axis may be convex.

[0018] In the above optical axis, the sixth lens may have a convex meniscus shape toward the sensor.

[0019] The following condition can be satisfied. <Condition> 0.01 < CG2 / ΣCG < 0.2 (In the above condition, CG2 is the center spacing between the second lens and the third lens, and ΣCG is the sum of the center spacings between adjacent lenses.)

[0020] The following condition can be satisfied. <Condition> 0.3 < CT2 / CG2 < 1 (In the above condition, CT2 is the central thickness of the second lens, and CG2 is the central gap between the second lens and the third lens.)

[0021] The following condition can be satisfied. <Condition> 1.5 < n1 < 1.6 (In the above condition, n1 means the refractive index at the d-line of the first lens.)

[0022]

[0023] In order to solve the above technical problem, an optical system according to an embodiment of the present invention includes first to seventh lenses arranged along an optical axis, wherein the first lens has positive (+) refractive power, the second lens has negative (-) refractive power, the fifth lens has positive (+) refractive power, the sixth lens has positive (+) refractive power, and the seventh lens has negative (-) refractive power, and the sign of the curvature radius of the sensor-side surface of the second lens and the sign of the curvature radius of the object-side surface of the third lens are the same.

[0024] The distance between the second lens and the third lens on the optical axis may be greater than the thickness of the first lens.

[0025] In the above optical axis, the fourth lens may have a meniscus shape convex toward the object side.

[0026] In the above optical axis, the third lens may have a meniscus shape convex toward the object side.

[0027] Among the first to seventh lenses on the optical axis, the thickness of the second lens may be the smallest.

[0028] The third lens may have positive (+) refractive power, and the fourth lens may have negative (-) refractive power.

[0029] The following condition can be satisfied. <Condition> 5 < TTL < 10 (In the above condition, TTL means the distance from the object side of the first lens to the upper surface of the image sensor on the optical axis.)

[0030] The following condition can be satisfied. <Condition> 0.1 < L2R2 / L3R1 < 1 (In the above condition, L2R2 is the radius of curvature of the sensor side of the second lens, and L3R1 is the radius of curvature of the object side of the third lens.)

[0031] In order to solve the above technical problem, an optical system according to an embodiment of the present invention includes first to seventh lenses arranged along an optical axis, wherein the fifth lens has positive (+) refractive power, the sixth lens has positive (+) refractive power, the seventh lens has negative (-) refractive power, and a distance between the second lens and the third lens on the optical axis is greater than a thickness of the first lens.

[0032] In the optical axis, the third lens may have a meniscus shape convex toward the object side, and in the optical axis, the fourth lens may have a meniscus shape convex toward the object side.

[0033] Among the first to seventh lenses on the optical axis, the thickness of the first lens may be the largest.

[0034] The thickness of the first lens on the optical axis may be smaller than the distance between the sixth lens and the seventh lens.

[0035] The following condition can be satisfied. <Condition> 0.1 < CG2 / ΣCG < 1 (In the above condition, CG2 is the center spacing between the second lens and the third lens, and ΣCG is the sum of the center spacings between adjacent lenses.)

[0036] The following condition can be satisfied. <Condition> 1.5 < n1 < 1.7 (In the above condition, n1 means the refractive index at the d-line of the first lens.)

[0037] The following condition can be satisfied. <Condition> 5 < F < 10 (In the above condition, F means the total focal length of the optical system.)

[0038]

[0039] In order to solve the above technical problem, an optical system according to the present embodiment includes a first lens group and a second lens group arranged along an optical axis, the first lens group including at least one lens, the second lens group including at least one lens, the first lens group having a positive (+) refractive power, the number of lenses included in the first lens group being smaller than the number of lenses included in the second lens group, and a distance between the first lens group and the second lens group on the optical axis being the largest among distances between adjacent lenses.

[0040] An aperture movable in the optical axis direction may be arranged between the first lens group and the second lens group.

[0041] The first lens group may include a first lens having positive (+) refractive power and a second lens having negative (-) refractive power, and the second lens group may include third to seventh lenses.

[0042] The third lens may have positive (+) refractive power, the fourth lens may have negative (-) refractive power, the fifth lens may have positive (+) refractive power, the sixth lens may have negative (-) refractive power, and the seventh lens may have negative (-) refractive power.

[0043] Among the first to seventh lenses on the optical axis, the thickness of the first lens may be the largest.

[0044] The sign of the curvature radius of the sensor side of the second lens and the sign of the curvature radius of the object side of the third lens may be the same.

[0045] The above second lens may have a meniscus shape convex toward the object side.

[0046] The following condition can be satisfied. <Condition> 0.1 < CG2 / TTL < 0.3 (In the above condition, CG2 means the center gap between the second lens and the third lens, and TTL means the distance from the object side of the first lens to the upper surface of the image sensor on the optical axis.)

[0047] The following condition can be satisfied. <Condition> 1 < LG1_F / F < 1.5 (In the above condition, LG1_F means the focal length of the first lens group, and F means the entire focal length of the optical system.)

[0048] In order to solve the above technical problem, an optical system according to the present embodiment includes first to seventh lenses arranged along an optical axis, wherein the first lens has positive (+) refractive power, the second lens has negative (-) refractive power, the third lens has positive (+) refractive power, and the fourth lens has negative (-) refractive power, and a distance between the second lens and the third lens on the optical axis may be the largest among distances between adjacent lenses.

[0049] Among the first to seventh lenses on the optical axis, the thickness of the first lens may be the largest.

[0050] The sign of the curvature radius of the sensor side of the second lens and the sign of the curvature radius of the object side of the third lens may be the same.

[0051] An aperture movable in the optical axis direction may be arranged between the first lens group and the second lens group.

[0052] The following condition can be satisfied. <Condition> 0.1 < CT1 / ΣCT < 0.5 (In the above condition, CT1 is the central thickness of the first lens, and ΣCT means the sum of the central thicknesses of the lenses.)

[0053] The following condition can be satisfied. <Condition> 0.1 < ΣCG / TTL < 0.5 (In the above condition, ΣCG is the sum of the spacings between adjacent lenses, and TTL means the distance on the optical axis from the object side of the first lens to the upper surface of the image sensor.)

[0054] An optical system according to an embodiment can have good optical performance by changing the aperture position according to a shooting environment. In addition, the optical system and camera module according to the embodiment can have improved optical characteristics. Specifically, in the optical system according to the embodiment, a plurality of lenses can have set thicknesses, refractive powers, and spacings from adjacent lenses. Accordingly, the optical system and camera module according to the embodiment can have improved MTF characteristics, aberration control characteristics, resolution characteristics, etc. in a set field of view range, and can have good optical performance in the periphery of the field of view.

[0055] Additionally, the optical system and camera module according to the embodiment can satisfy the set angle of view and exhibit excellent optical characteristics. This allows the optical system to provide a slimmer camera module. Accordingly, the optical system and camera module can be used in various applications and devices.

[0056] FIG. 1 is a side cross-sectional view of an optical system and a camera module having the same according to a first embodiment.

[0057] Figure 2 is a table showing the aspherical coefficients of lenses in the optical system of Figure 1.

[0058] Fig. 3 is a table showing the Sag values ​​of the lens surfaces of the first to eighth lenses in the optical system of Fig. 1.

[0059] Figure 4 is a table showing the thickness of lenses and the spacing between lenses in the direction perpendicular to the optical axis in the optical system of Figure 1.

[0060] Fig. 5 is a table showing the slope angles of the lens surfaces of the first to eighth lenses in the optical system of Fig. 1.

[0061] Figure 6 is a graph showing data on the diffraction MTF (Modulation Transfer Function) of the optical system of Figure 1.

[0062] Fig. 7 is a graph showing data on the aberration characteristics of the optical system of Fig. 1.

[0063] Figure 8 is a graph showing data on relative illumination versus relative field according to the relative field height of the optical system of Figure 1.

[0064] Fig. 9 is a side cross-sectional view of an optical system and a camera module having the same according to a second embodiment.

[0065] Figure 10 is a table showing the aspherical coefficients of lenses in the optical system of Figure 9.

[0066] Fig. 11 is a table showing the Sag values ​​of the lens surfaces of the first to eighth lenses in the optical system of Fig. 9.

[0067] Figure 12 is a table showing the thickness of lenses and the spacing between lenses in the direction perpendicular to the optical axis in the optical system of Figure 9.

[0068] Fig. 13 is a table showing the slope angles of the lens surfaces of the first to eighth lenses in the optical system of Fig. 9.

[0069] Figure 14 is a graph showing data on the diffraction MTF (Modulation Transfer Function) of the optical system of Figure 9.

[0070] Fig. 15 is a graph showing data on the aberration characteristics of the optical system of Fig. 9.

[0071] Figure 16 is a graph showing data on relative illumination versus relative field according to the relative field height of the optical system of Figure 9.

[0072] Fig. 17 is a side cross-sectional view of an optical system and a camera module having the same according to a third embodiment.

[0073] Fig. 18 is a table showing the aspherical coefficients of lenses in the optical system of Fig. 17.

[0074] Fig. 19 is a table showing the Sag values ​​of the lens surfaces of the first to seventh lenses in the optical system of Fig. 17.

[0075] Fig. 20 is a table showing the thickness of lenses and the spacing between lenses in the direction perpendicular to the optical axis in the optical system of Fig. 17.

[0076] Fig. 21 is a table showing the slope angles of the lens surfaces of the first to seventh lenses in the optical system of Fig. 17.

[0077] Figure 22 is a graph showing data on the diffraction MTF (Modulation Transfer Function) of the optical system of Figure 17.

[0078] Fig. 23 is a graph showing data on the aberration characteristics of the optical system of Fig. 17.

[0079] Figure 24 is a graph showing data on relative illumination versus relative field according to the relative field height of the optical system of Figure 17.

[0080] Fig. 25 is a side cross-sectional view of an optical system and a camera module having the same according to the fourth embodiment.

[0081] Fig. 26 is a table showing the aspherical coefficients of lenses in the optical system of Fig. 25.

[0082] Fig. 27 is a table showing the Sag values ​​of the lens surfaces of the first to seventh lenses in the optical system of Fig. 25.

[0083] Figure 28 is a table showing the thickness of lenses and the spacing between lenses in the direction perpendicular to the optical axis in the optical system of Figure 25.

[0084] Fig. 29 is a table showing the slope angles of the lens surfaces of the first to seventh lenses in the optical system of Fig. 25.

[0085] Figure 30 is a graph showing data on the diffraction MTF (Modulation Transfer Function) of the optical system of Figure 25.

[0086] Fig. 31 is a graph showing data on the aberration characteristics of the optical system of Fig. 25.

[0087] Figure 32 is a graph showing data on relative illumination versus relative field according to the relative field height of the optical system of Figure 25.

[0088] Figure 33 is a configuration diagram of an optical system according to a fifth embodiment operating in the first mode.

[0089] Figure 34 is a configuration diagram of an optical system according to a fifth embodiment operating in the second mode.

[0090] Figure 35 is a table showing the aspherical coefficients of lenses in an optical system according to the fifth embodiment.

[0091] Fig. 36 is a table showing the Sag values ​​of the lens surfaces of the first to seventh lenses of the optical system according to the fifth embodiment.

[0092] Figure 37 is a table showing the spacing between the first to seventh lenses of the optical system according to the fifth embodiment.

[0093] Fig. 38 is a table showing the slope angles of the lens surfaces of the first to seventh lenses of the optical system according to the fifth embodiment.

[0094] Figure 39 is a graph showing data on the diffraction MTF (Modulation Transfer Function) of the optical system according to the fifth embodiment operating in the first mode.

[0095] Figure 40 is a graph showing data on the diffraction MTF (Modulation Transfer Function) of the optical system according to the fifth embodiment operating in the second mode.

[0096] Fig. 41 is a graph showing data on aberration characteristics of an optical system according to a fifth embodiment operating in the first mode.

[0097] Fig. 42 is a graph showing data on aberration characteristics of an optical system according to a fifth embodiment operating in the second mode.

[0098] Figure 43 is a configuration diagram of an optical system according to the sixth embodiment operating in the first mode.

[0099] Figure 44 is a configuration diagram of an optical system according to the sixth embodiment operating in the second mode.

[0100] Figure 45 is a table showing the aspherical coefficients of lenses in an optical system according to the sixth embodiment.

[0101] Fig. 46 is a table showing the Sag values ​​of the lens surfaces of the first to seventh lenses of the optical system according to the sixth embodiment.

[0102] Figure 47 is a table showing the spacing between the first to seventh lenses of the optical system according to the sixth embodiment.

[0103] Fig. 48 is a table showing the slope angles of the lens surfaces of the first to seventh lenses of the optical system according to the sixth embodiment.

[0104] Figure 49 is a graph showing data on the diffraction MTF (Modulation Transfer Function) of the optical system according to the sixth embodiment operating in the first mode.

[0105] Figure 50 is a graph showing data on the diffraction MTF (Modulation Transfer Function) of the optical system according to the sixth embodiment operating in the second mode.

[0106] Fig. 51 is a graph showing data on aberration characteristics of an optical system according to the sixth embodiment operating in the first mode.

[0107] Figure 52 is a graph showing data on aberration characteristics of an optical system according to the sixth embodiment operating in the second mode.

[0108] Figure 53 is an exploded perspective view of a camera module according to the present embodiment.

[0109] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings.

[0110] 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.

[0111] 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.

[0112] Additionally, the terms used in this embodiment are for the purpose of describing the embodiments and are not intended to limit the present invention.

[0113] 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.

[0114] 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.

[0115] 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.

[0116] 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.

[0117] 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.

[0118]

[0119] The optical system (1000, 1100, 1200, 1300, 1400, 1500) according to the first to sixth embodiments of the present invention may include seven or more lenses. The optical system (1000, 1100, 1200, 1300, 1400, 1500) may include n lenses, 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 7, and may be, for example, 7 to 8.

[0120] The optical system (1000, 1100, 1200, 1300, 1400, 1500) or camera module may include a plurality of lens groups (LG1, LG2). For example, the optical system (1000, 1100, 1200, 1300, 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 second lens group (LG2) may be arranged on the sensor side of the first lens group (LG1). Each of the plurality of lens groups (LG1, LG2) includes at least two lenses. The number of lenses in the second lens group (LG2) may be equal to or greater than the number of lenses in the first lens group (LG1), and may be, for example, one to three times greater than the number of lenses in the first lens group (LG1).

[0121] The first lens group (LG1) may include five or fewer lenses. The first lens group (LG1) may include, for example, four lenses in the first and second embodiments, three lenses in the third and fourth embodiments, and two lenses in the fifth and sixth embodiments. The second lens group (LG2) may include four or more and six or fewer lenses. The second lens group (LG2) may include, for example, four lenses in the first and second embodiments, five lenses in the third and fourth embodiments, and six lenses in the fifth and sixth embodiments. The optical system (1000, 1100, 1200, 1300, 1400, 1500) may include eight or fewer lenses.

[0122]

[0123] The first lens group (LG1) may have positive refractive power. In the first and second embodiments, the second lens group (LG2) may have the same positive refractive power as the first lens group (LG1). In the third to sixth embodiments, the second lens group (LG2) may have negative refractive power, unlike the first lens group (LG1). In the first to sixth embodiments, the first lens group (LG1) and the second lens group (LG2) have different focal lengths, so that they may have good optical performance at the center and periphery of the field of view (FOV). Refractive power is the reciprocal of the focal length. Among the lenses of the first lens group (LG1), the lens closest to the object side may have positive refractive power, and among the lenses of the second lens group (LG2), the lens closest to the sensor side may have negative refractive power.

[0124] The first lens group (LG1) refracts light incident through the object side to gather it, and the second lens group (LG2) can refract light emitted through the first lens group (LG1) to the periphery of the image sensor (700). In the first and second lens groups (LG1, LG2) of the first to fourth embodiments, two lens surfaces facing each other, for example, the sensor-side surface of the first lens group (LG1) may be concave on the optical axis, and the object-side surface of the second lens group (LG2) may be convex.

[0125] The focal length of the second lens group (LG2) may be greater than the focal length of the first lens group (LG1). For example, the focal length of the second lens group (LG2) may be more than twice the focal length of the first lens group (LG1). Accordingly, the optical system (1000, 1100, 1200, 1300, 1400, 1500) according to the embodiment may have improved aberration control characteristics such as chromatic aberration and distortion aberration by controlling the refractive power and focal length of each lens group (LG1, LG2), and may have good optical performance at the center and periphery of the field of view (FOV).

[0126] The composite focal length (f1~4) of the first lens group (LG1) may be 5 to 10. The composite focal length (f5~8) of the second lens group (LG2) may be -10 to -110. The absolute value of the composite focal length of the first lens group (LG1) may be smaller than the absolute value of the composite focal length of the second lens group (LG2). The power of the first lens group (LG1) may be greater than the power of the second lens group (LG2).

[0127]

[0128] Each lens (101-108, 201-208, 301-307, 401-407, 501-507, 601-607) can have an object side and a sensor side. The optical system (1000, 1100, 1200, 1300, 1400, 1500) has aspherical lenses, so it can correct various aberrations.

[0129] 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, 9, 17, 25, 33, 34, 43, and 43, 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.

[0130] Each of the lenses (101-108, 201-208, 301-307, 401-407, 501-507, 601-607) 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.

[0131]

[0132] Within the optical system (1000, 1100, 1200, 1300, 1400, 1500), the TTL (Total top length) may be more than 1 time, for example, more than 1 time and less than 1.8 times, than the Imgh. The TTL (Total track length) is the distance from the center of the object-side surface of the first lens to the top surface of the image sensor (700) on the optical axis (OA). The Imgh is the distance from the optical axis (OA) to the diagonal end of the image sensor (700) or half of the maximum diagonal length. Within the optical system (1000, 1100, 1200, 1300, 1400, 1500), the effective focal length (EFL) may be provided to be more than 6 mm and the field of view (FOV) to be less than 90 degrees. Accordingly, the optical system (1000, 1100, 1200, 1300, 1400, 1500) can provide an image without exaggeration or distortion for the image being formed.

[0133] In the lens units of the first to second embodiments, the effective diameter of the lens closest to the object side may be larger than the effective diameter of the lens closest to the image sensor (700), and in the lens units of the third to sixth embodiments, the effective diameter of the lens closest to the object side may be smaller 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 sensor-side surfaces of each lens. By controlling the effective diameter size of each lens, the optical system (1000, 1100, 1200, 1300, 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, 1300, 1400, 1500).

[0134] Since the lens unit uses a plastic lens, the optical system (1000, 1100, 1200, 1300, 1400, 1500) can provide weight reduction and low cost by reducing the thickness of the plastic lens, and the plastic lens can provide good correction for various aberrations such as spherical aberration and chromatic aberration. In addition, since the plastic lens can provide an aspherical lens, the distortion part in the peripheral area can be minimized.

[0135] The lens section 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), a sixth lens (106, 206, 306, 406, 506, 606) and a seventh lens (107, 207, 307, 407, 507, 607) aligned from the object side toward the sensor side along the optical axis, and the lens section of the first and second embodiments may include an eighth lens (108, 208). Can be.

[0136]

[0137] The optical system (1000, 1100, 1200, 1300, 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).

[0138]

[0139] The optical system (1000, 1100, 1200, 1300, 1400, 1500) or camera module may include a filter. The filter may be positioned between the last lens and the image sensor (700). The filter 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 may be positioned between the nth lens and the image sensor (700).

[0140] The cover glass (400) is placed between the filter 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 being deteriorated. The cover glass (400) can be removed. The cover glass (400) may be a protective glass.

[0141] The filter may include an infrared filter or an infrared cut-off filter (IR cut-off). The filter can pass light of a set wavelength band and filter out light of a different wavelength band. If the filter includes an infrared filter, it can block radiant heat emitted from external light from being transmitted to the image sensor (700). Additionally, the filter can transmit visible light and reflect infrared light.

[0142]

[0143] The optical system (1000, 1100, 1200, 1300, 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, 1300, 1400, 1500). The optical system (1000, 1100, 1200, 1300, 1400, 1500) according to the embodiment may have an aperture device positioned between two adjacent lenses. The aperture device can control the amount of light passing through the lenses. The aperture device can control the amount of light incident on the image sensor (700). The aperture device can control the size of a hole through which light passes.

[0144] The aperture device can be arranged on the lens. The aperture device can be arranged on the lens. The aperture device can be combined with the lens. The aperture device can be fixed to the lens. The aperture device can move integrally with the lens. The aperture device can move together with the lens. The aperture device can move along the optical axis together with the lens.

[0145] The distance between the lenses on which the aperture device is arranged may be greater than the center distance by the edge distance. The edge distance between the lenses on which the aperture device is arranged may be 0.3 mm or more and 1.6 mm or less, and preferably 0.4 mm or more and 1.5 mm or less. The ratio of the edge distance to the center distance between the lenses on which the aperture device is arranged may be 0.3 or more and 1.5 or less, and preferably 0.4 or more and 1.1 or less.

[0146] The signs of the curvature radii of the sensor-side surface of the lens adjacent to the object side and the object-side surface of the lens adjacent to the sensor side may be the same. The ratio of the curvature radii of the object-side surface of the lens adjacent to the sensor side to the curvature radii of the sensor-side surface of the lens adjacent to the object side and the aperture device may be 0.1 or more and 3 or less, and preferably 0.3 or more and 2.5 or less.

[0147] For example, when the aperture device is placed between the second lens (102, 202, 302, 402, 502, 602) and the third lens (103, 203, 303, 403, 503, 603), the signs of the curvature radii of the sensor side (fourth surface (S4)) of the second lens (102, 202, 302, 402, 502, 602) and the object side (fifth surface (S5)) of the third lens (103, 203, 303, 403, 503, 603) may be the same. The sensor-side surface (fourth surface (S4)) of the second lens (102, 202, 302, 402, 502, 602) may have a concave shape, and the object-side surface (fifth surface (S5)) of the third lens (103, 203, 303, 403, 503, 603) may have a convex shape. Through this, interference between the aperture device and the lens or interference between the operation of the blades of the aperture device and the lens can be minimized.

[0148] In the fifth and sixth embodiments, an aperture may be arranged between the first lens group (LG1) and the second lens group (LG2). The aperture may be moved in the direction of the optical axis by an aperture device. As the aperture moves, the distance between adjacent lenses and the aperture may change. The aperture may be a moving group, and the lens unit may be a fixed group. A state in which the aperture is arranged closest to the first lens group (LG1) may be referred to as a first mode, and a state in which the aperture is arranged closest to the second lens group (LG2) may be referred to as a second mode. The diameter of light incident on the first lens (501, 601) in the first mode may be smaller than the diameter of light incident on the first lens (501, 601) in the second mode.

[0149] Among the gaps between adjacent lenses, the gap between the lens arranged on the sensor side of the first lens group (LG1) and the lens arranged on the object side of the second lens group (LG1) may be the largest. Among the gaps between adjacent lenses, the gap between the second lens (502, 602) and the third lens (503, 603) may be the largest.

[0150] In the fifth and sixth embodiments, the optical system (1400, 1500) can satisfy an F number of 2.2 or more and 2.3 or less in the first mode, and an F number of 1.8 or more and 2.1 or less in the second mode. When the F number decreases, the depth of field becomes shallow and the background becomes blurred, and when the F number increases, the depth of field becomes deep and the entire image becomes in focus.

[0151] Because the hole formed by the aperture is not a perfect circle, a side effect called the starburst effect can occur. Diffraction is a type of lens flare, where light passing through the aperture diffracts, creating radial lines. To prevent this diffraction effect, the aperture can be adjusted along the optical axis.

[0152] In the fifth and sixth embodiments, the first lens group (LG1) arranged on the object side of the aperture may have positive (+) refractive power. If the refractive power of the first lens group (LG1) is designed to be strong, the F number may be greatly affected depending on the movement of the aperture. If the aperture is arranged in the central area of ​​the optical system, it is difficult to set the refractive power of the first lens group (LG1) to be strong, and there is a problem that the diameter of the first lens (501, 601) must be large. Therefore, the number of lenses arranged on the object side of the aperture may be less than the number of lenses arranged on the sensor side of the aperture.

[0153]

[0154] In the optical systems (1000, 1100, 1200, 1300, 1400, 1500) of the first to sixth embodiments, the sum of the refractive indices of the lenses of the lens unit may be 8 or more, for example, in the range of 8 to 15, and the average of the refractive indices may be in the range of 1.55 to 1.7. The sum of the Abbe numbers of each of the lenses may be 270 or more, for example, in the range of 270 to 350, and the average of the Abbe numbers may be 50 or less, for example, in the range of 35 to 47. The sum of the central thicknesses of the entire lens may be 4 mm or more, for example, in the range of 4 mm to 30 mm, and the average of the central thicknesses may be in the range of 0.5 mm to 4.0 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 6 mm, and may be smaller than the sum of the central thicknesses of the lenses. Additionally, the average value of the effective diameter of each lens surface of the lens unit can be provided in the range of 5 mm or more, for example, 5 mm to 15 mm.

[0155]

[0156] The F number of the optical system or camera module according to the first and second embodiments of the invention may be 2.4 or less, for example, in the range of 1.5 to 2.3. The maximum angle of view (diagonal) of the optical system according to the embodiment of the invention may be 90 degrees or less, for example, in the range of 70 to 90 degrees. The horizontal angle of view (FOV_H) of the optical system may be greater than 50 degrees and less than 80 degrees, for example, in the range of 53 to 75 degrees. The vertical angle of view (FOV_V) of the optical system may be greater than 50 degrees and less than 75 degrees, for example, in the range of 50 to 72 degrees. At this time, in the first and second embodiments, the sensor length in the horizontal direction may be 3.66 mm ± 0.5 mm, and the sensor length in the vertical direction may be 4.88 mm ± 0.5 mm, in the third and fourth embodiments, the sensor length in the horizontal direction may be 9.84 mm ± 0.5 mm, and the sensor length in the vertical direction may be 7.38 mm ± 0.5 mm, and in the fifth and sixth embodiments, the sensor length in the horizontal direction (X) may be 7.872 mm ± 0.5 mm, and the sensor height in the vertical direction (Y) may be 5.904 mm ± 0.5 mm. The horizontal field of view (FOV_H) is the field of view based on the horizontal length of the sensor.

[0157]

[0158] An optical system according to a first embodiment of the invention will be described.

[0159] Referring to FIG. 1, the optical system (1000) includes a lens unit, and the lens unit may include a first lens (101) to an eighth lens (108). The first to eighth lenses (101 to 108) may be sequentially arranged along the optical axis (OA) of the optical system (1000). Light corresponding to information on an object may pass through the first lens (101) to the eighth lens (108) and a filter and be incident on the image sensor (700).

[0160] 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 positive (+) refractive power on the optical axis (OA). The first lens (101) may include a plastic material or a glass material, and may be, for example, a plastic material. At least one or both of the first surface (S1) and the second surface (S2) may be aspherical. The aspherical coefficients of the first and second surfaces (S1, S2) may be provided as S1 and S2 of L1 in FIG. 2.

[0161] The first surface (S1) on the object side of the first lens (101) with respect to the optical axis may be convex, and the second surface (S2) on the sensor side may be concave. The first lens (101) may have a concave meniscus shape toward the sensor side. The first lens (101) may have a convex meniscus shape toward the object side. The first lens (101) is made of a plastic material and may have an aspherical surface.

[0162] The refractive index (n1) of the first lens (101) can satisfy the condition of n1>1.5 or n1>1.52. When the refractive index (n1) of the first lens (101) satisfies the condition, the radius of curvature of the first and second lenses (101, 102) can be increased, and lens manufacturing can be facilitated. When the refractive index (n1) of the first lens (101) is smaller than the condition, the lens surface must be formed to be sharply concave or convex in order to increase the refractive power of the first and second lenses (101, 102). In this case, lens manufacturing is not easy, the lens defect rate increases, and this may cause a decrease in yield.

[0163] The first surface (S1) of the first lens (101) may be provided without a critical point from the optical axis (OA) to the end of the effective area. The second surface (S2) of the first lens (101) may have a critical point from the optical axis (OA) to the end of the effective area. When the second surface (S2) has a critical point, it may be located in a range of 90% to 99%, preferably in a range of 93% to 97%, of the effective radius from the optical axis (OA). The critical point of the second surface (S2) may be located in a range of 1.5 mm to 2.1 mm, preferably in a range of 1.8 mm to 2.1 mm from the optical axis (OA).

[0164] The critical point of the second surface (S2) is a point where the sign of the slope value with respect to the optical axis (OA) and the direction perpendicular to the optical axis (OA) changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the slope value is 0. In addition, the critical point of the second surface (S2) may be a point where the slope value of the tangent line passing through the lens surface increases and then decreases, or a point where the slope value decreases and then increases.

[0165]

[0166] The second lens (102) may be arranged second from the object side. The second lens (102) may be arranged seventh from the sensor side. The second lens (102) may be arranged between the first lens (101) and the third lens (103). The second lens (102) may have negative (-) 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.

[0167] The third surface (S3) on the object side of the second lens (102) with respect to the optical axis (OA) may be convex, and the fourth surface (S4) on the sensor side may be concave. The second lens (102) may have a concave meniscus shape toward the sensor side. The second lens (102) may have a convex meniscus shape toward the object side. The second lens (102) 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. 2.

[0168] The third surface (S3) of the second lens (102) may have a critical point from the optical axis (OA) to the end of the effective area. The fourth surface (S4) of the second lens (102) may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0169] When the third surface (S3) has a critical point, it may be located in a range of 90% to 98%, preferably 93% to 96%, of the effective radius from the optical axis (OA). The critical point of the third surface (S3) may be located in a range of 1.5 mm to 2 mm, preferably 1.8 mm to 2 mm from the optical axis (OA).

[0170] The critical point of the third surface (S3) is the point where the sign of the slope value with respect to the optical axis (OA) and the direction perpendicular to the optical axis (OA) changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean the point where the slope value is 0. In addition, the critical point of the third surface (S3) may be the point where the slope value of the tangent line passing through the lens surface increases and then decreases, or the point where the slope value decreases and then increases.

[0171] The aperture (Stop) may be arranged around the sensor-side fourth surface (S4) of the second lens (102). The aperture (Stop) may be arranged around the object-side fifth surface (S5) of the third lens (103). The aperture can reduce the TTL within the field of view range and enable 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.

[0172]

[0173] The third lens (103) may be arranged third from the object side. The third lens (103) may be arranged sixth from the sensor side. The third lens (103) may be arranged between the second lens (102) and the fourth lens (104). The third lens (103) may have negative (-) refractive power on the optical axis (OA). The third lens (103) may include a plastic or glass material. For example, the third lens (103) may be provided as a plastic material.

[0174] The fifth surface (S5) on the object side of the third lens (103) with respect to the optical axis may be convex, and the sixth surface (S6) on the sensor side may be concave. The third lens (103) may have a meniscus shape in which the sensor side is concave. The third lens (103) may have a meniscus shape in which the object side is convex. The third lens (103) is made of a plastic material and may be aspherical. At least one or both of the fifth surface (S5) and the sixth surface (S6) may be aspherical. The aspherical coefficients of the fifth and sixth surfaces (S5, S6) may be provided as S1 and S2 of L3 in FIG. 2. At least one or both of the fifth surface (S5) and the sixth surface (S6) may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0175]

[0176] The fourth lens (104) may be arranged fourth from the object side. The fourth lens (104) may be arranged fifth from the sensor side. The fourth lens (104) may be arranged between the third lens (103) and the fifth lens (105). The fourth lens (104) may have positive (+) or negative (-) refractive power on the optical axis (OA). The fourth lens (104) may have positive (+) refractive power. Unlike the refractive power of the fifth lens (105), the fourth lens (104) may have positive (+) refractive power. The fourth lens (104) may include a plastic or glass material. For example, the fourth lens (104) may be provided with a plastic material.

[0177] The seventh surface (S7) on the object side of the fourth lens (104) with respect to the optical axis may be concave, and the eighth surface (S8) on the sensor side may be convex. The fourth lens (104) may have a meniscus shape with a convex side on the sensor side. The fourth lens (104) may have a meniscus shape with a concave side on the object side. The fourth lens (104) is made of a plastic material and may have an aspherical surface. 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. 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.

[0178]

[0179] The fifth lens (105) may be arranged as the fifth lens from the object side. The fifth lens (105) may be arranged as the fourth lens from the sensor side. The fifth lens (105) may be arranged between the fourth lens (104) and the sixth lens (106). The fifth lens (105) may have positive (+) or negative (-) refractive power on the optical axis (OA). The fifth lens (105) may have negative (-) refractive power. Unlike the refractive power of the fourth lens (104), the fifth lens (105) may have negative (-) refractive power. The fifth lens (105) may include a plastic or glass material. For example, the fifth lens (105) may be provided as a plastic material.

[0180] 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 concave. The fifth lens (105) may have a concave meniscus shape on the sensor side. The fifth lens (105) may have a convex meniscus shape on the object side. The fifth lens (105) may be made of a plastic material and may have an aspherical surface. At least one of the ninth surface (S9) and the tenth surface (S10) may be an aspherical surface. The aspherical coefficients of the ninth and tenth surfaces (S9, S10) may be provided as S1 and S2 of L5 in FIG. 2.

[0181] The ninth surface (S9) of the fifth lens (105) may have a critical point from the optical axis (OA) to the end of the effective area. When the ninth surface (S9) has a critical point, it may be located in a range of 50% to 70%, preferably in a range of 52% to 55%, of the effective radius from the optical axis (OA). The critical point of the ninth surface (S9) may be located in a range of 1.0 mm to 2 mm, preferably in a range of 1.2 mm to 1.6 mm from the optical axis (OA).

[0182] The critical point of the ninth surface (S9) is a point where the sign of the slope value with respect to the optical axis (OA) and the direction perpendicular to the optical axis (OA) changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the slope value is 0. In addition, the critical point of the ninth surface (S9) may be a point where the slope value of the tangent line passing through the lens surface increases and then decreases, or a point where the slope value decreases and then increases.

[0183] The tenth surface (S10) of the fifth lens (105) may have a critical point from the optical axis (OA) to the end of the effective area. When the tenth surface (S10) has a critical point, it may be located in a range of 50% to 70%, preferably 55% to 60%, of the effective radius from the optical axis (OA). The critical point of the tenth surface (S10) may be located in a range of 1.0 mm to 2 mm, preferably 1.5 mm to 1.8 mm from the optical axis (OA).

[0184] The critical point of the tenth surface (S10) is a point where the sign of the slope value with respect to the optical axis (OA) and the direction perpendicular to the optical axis (OA) changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the slope value is 0. In addition, the critical point of the tenth surface (S10) may be a point where the slope value of the tangent line passing through the lens surface increases and then decreases, or a point where the slope value decreases and then increases.

[0185]

[0186] The sixth lens (106) may be arranged as the sixth lens from the object side. The sixth lens (106) may be arranged as the third lens from the sensor side. The sixth lens (106) may be arranged between the fifth lens (105) and the seventh lens (107). The sixth lens (106) may have positive (+) or negative (-) refractive power on the optical axis (OA). The sixth lens (106) may have positive (+) refractive power. The sixth lens (106) may include a plastic or glass material. For example, the sixth lens (106) may be provided as a plastic material.

[0187] The sixth lens (106) may have a convex shape on the object-side eleventh surface (S11) and a convex shape on the sensor-side twelveth surface (S12) with respect to the optical axis (OA). The sixth lens (106) may have a convex shape on both sides with respect to the optical axis (OA). At least one or both of the eleventh surface (S11) and the twelfth surface (S12) may be aspherical. The aspherical coefficients of the eleventh and twelfth surfaces (S11, S12) may be provided as S1 and S2 of L6 in FIG. 2.

[0188] The eleventh surface (S11) of the sixth lens (105) may have 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 be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0189] When the eleventh surface (S11) has a critical point, it may be located in a range of 30% to 40%, preferably in a range of 35% to 38%, of the effective radius from the optical axis (OA). The critical point of the eleventh surface (S11) may be located in a range of 1.0 mm to 2 mm, preferably in a range of 1.0 mm to 1.3 mm from the optical axis (OA).

[0190] The critical point of the eleventh surface (S11) is a point where the sign of the slope value with respect to the optical axis (OA) and the direction perpendicular to the optical axis (OA) changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the slope value is 0. In addition, the critical point of the eleventh surface (S11) may be a point where the slope value of the tangent line passing through the lens surface increases and then decreases, or a point where the slope value decreases and then increases.

[0191]

[0192] The seventh lens (107) may be arranged as the seventh lens from the object side. The seventh lens (107) may be arranged as the second lens from the sensor side. The seventh lens (107) may be arranged between the sixth lens (106) and the eighth lens (108). The seventh lens (107) may have positive (+) refractive power on the optical axis (OA). The seventh lens (107) may include a plastic or glass material. For example, the seventh lens (107) may be provided as a plastic material.

[0193] The object-side 13th surface (S13) of the seventh lens (107) may be concave with respect to the optical axis, and the sensor-side 14th surface (S14) may be convex. The seventh lens (107) may have a meniscus shape in which the sensor side is convex. The seventh lens (107) may have a meniscus shape in which the object side is concave. The seventh lens (107) may be made of a plastic material and may be aspherical. At least one or both of the 13th surface (S13) and the 14th surface (S14) may be aspherical. The aspherical coefficients of the 13th and 14th surfaces (S13, S14) may be provided as S1 and S2 of L7 in FIG. 2. The 13th surface (S13) and the 14th surface (S14) of the seventh lens may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0194]

[0195] The eighth lens (108) may be arranged closest to the sensor side. The eighth lens (108) may be arranged farthest from the object side. The eighth lens (108) may have positive (+) or negative (-) refractive power on the optical axis (OA). The eighth lens (108) may have negative (-) refractive power. The eighth lens (108) may include a plastic or glass material. For example, the eighth lens (108) may be made of a plastic material.

[0196] The object-side 15th surface (S15) of the 8th lens (108) on the optical axis may be concave, and the sensor-side 16th surface (S16) may be concave. The 8th lens (108) may have a concave shape on both sides. At least one of the 15th surface (S15) and the 16th surface (S16) may be aspherical. For example, both the 15th surface (S15) and the 16th surface (S16) may be aspherical. The aspherical coefficients of the 15th and 16th surfaces (S15, S16) may be provided as S1 and S2 of L8 in FIG. 2.

[0197] The fifteenth surface (S15) of the eighth lens (108) may be provided without a critical point from the optical axis (OA) to the end of the effective area. The sixteenth surface (S16) of the eighth lens (108) may have a critical point from the optical axis (OA) to the end of the effective area. When the sixteenth surface (S16) has a critical point, it may be located in a range of 30% to 40%, preferably in a range of 35% to 38%, of the effective radius from the optical axis (OA). The critical point of the sixteenth surface (S16) may be located in a range of 1.5 mm to 2.1 mm, preferably in a range of 1.6 mm to 2.0 mm from the optical axis (OA).

[0198] The critical point of the 16th surface (S16) is a point where the sign of the slope value with respect to the optical axis (OA) and the direction perpendicular to the optical axis (OA) changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the slope value is 0. In addition, the critical point of the 16th surface (S16) may be a point where the slope value of the tangent line passing through the lens surface increases and then decreases, or a point where the slope value decreases and then increases.

[0199]

[0200] LensSurfaceRadiusThicknessndvdSemiApertureFocal length1S13.3310.9261.546856.33152.2007.5212 S215.8030.0542.1272S317.7120.2301.679519.24592.099-28.2306 S49.1610.1582.017 Stop-0.1371.9873 S53.7660.2301.679519.24591.939-93.6929S63.4680.8671.8754S7-24.5970.6891.546856.33151.90021.7644 S8-8.1000.1032.1005S94.4840.3001.679519.24592.643-22.5272 S103.3740.4942.8736S11173.3610.7071.546856.33153.0078.0836 S12-4.5290.5003.1937S13-9.9360.6001.679519.24593.65814.5725 S14-5.0811.1063.9068S15-3.1140.4001.570637.56474.010-4.037S169.2660.3004.911Cover glassS17 0.1005.922 S18 0.7005.959 Image 0.0006.402

[0201]

[0202] 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.

[0203]

[0204] Item ValueItem ValueF6.8340ET10.2295ΣIndex12.9290ET20.2828ΣAbbe283.5428ET30.3844ΣCT4.0825ET40 .2790ΣCG3.4175ET50.3815CA_max0.9263ET60.2997CA_min3.750ET70.2950CA_Aver5.557ET8 1.2327CT_max4.0825F-number1.6000CT_min0.2300FOV_D84.9CT_Aver0.5103FOV_V70.3EPD4 .2712FOV_H55.2BFL1.1000ImgH6.1000TD7.5000SD6.1323LG1_F7.892TTL8.6000LG2_F-18.514

[0205]

[0206] Table 2 shows the items of the mathematical formulas described above in the optical system (1000) of the embodiment, including the TTL (Total track length) (mm), BFL (Back focal length), effective focal length (F) (mm), ImgH (mm), effective diameter (CA) (mm), thickness (mm), TTL (mm), TD (mm), which is the optical axis distance from the first surface (S1) to the sixteenth surface (S16), SD (mm), which is the optical axis distance from the aperture (Stop) to the sixteenth surface (S16), sum of refractive indices, sum of Abbe numbers, sum of thicknesses (mm), sum of spacings between adjacent lenses, effective diameter characteristics, diagonal angle of view (FOV_D) (Degree), vertical angle of view (FOV_V) (Degree), horizontal angle of view (FOV_H) (Degree), edge thickness (ET), F number, composite focal length (LG1_F) of the first lens group (LG1), This is about the composite focal length (LG2_F) of the second lens group (LG2).

[0207]

[0208] The center thicknesses of the first to eighth lenses (101 to 108) are represented by CT1 to CT8, the edge thicknesses at the ends of the effective areas of each lens are represented by ET1 to ET8, the center gap between two adjacent lenses is represented by CG1 to CG7, and the edge gaps between the edges of each lens are represented by EG1 to EG7. The BFL (Back focal length) is the optical axis distance from the image sensor (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).

[0209] As shown in Fig. 2, among the lenses of the lens unit in the first embodiment, the lens surfaces of the first to eighth lenses (101 to 108) may include aspherical surfaces having a 30th aspherical coefficient. For example, the first to eighth lenses (101 to 108) may include lens surfaces having a 30th aspherical coefficient. As described above, an aspherical surface having a 30th 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).

[0210] When comparing the absolute values ​​of the curvature radii of each lens, the curvature radii of the eleventh surface (S11) of the sixth lens (106) on the optical axis (OA) may be the largest among the lenses, and the curvature radii of the fifteenth surface (S15) of the eighth lens (108) may be the smallest among the lenses. The difference between the maximum curvature radii and the minimum curvature radii may be 40 times or more, for example, in the range of 50 to 55 times. The curvature radii of the object-side surface of the eighth lens (108) arranged on the sensor side of the seventh lens (107) may be the smallest among the lenses.

[0211] The absolute value of the curvature radius of the first surface (S1) of the first lens (101) may be smaller 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 larger 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 larger 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 larger 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 larger than the absolute value of the curvature radius of the tenth surface (S10). The absolute value of the curvature radius of the eleventh surface (S11) of the sixth lens (106) may be greater than the absolute value of the curvature radius of the twelfth surface (S12). The absolute value of the curvature radius of the thirteenth surface (S13) of the seventh lens (107) may be greater than the absolute value of the curvature radius of the fourteenth surface (S14). The absolute value of the curvature radius of the fifteenth surface (S15) of the eighth lens (108) may be less than the absolute value of the curvature radius of the sixteenth surface (S16).

[0212] The ratio of the radius of curvature of each lens can satisfy the following conditions.

[0213] Condition 1: 0.1 < |L1R1 / L1R2| < 0.5

[0214] Condition 2: 1.5 < |L2R1 / L2R2| < 2

[0215] Condition 3: 1 < |L3R1 / L3R2| < 1.5

[0216] Condition 4: 3 < |L4R1 / L4R2| < 3.5

[0217] Condition 5: 1 < |L5R1 / L5R2| < 1.5

[0218] Condition 6: 30 < |L6R1 / L6R2| < 40

[0219] Condition 7: 1.5 < |L7R1 / L7R2| < 2

[0220] Condition 8: 0.1 < |L8R1 / L8R2| < 0.5

[0221]

[0222] When describing the central thickness of the lenses based on the optical axis, the central thickness (CT1) of the first lens (101) is the largest among the lenses, and the central thickness (CT2) of the second lens (102) and the central thickness (CT3) of the third lens are the smallest among the lenses. The difference between the maximum and minimum central thicknesses among the lenses may be in the range of 0.5 mm or more and 1 mm or less.

[0223] By setting the center thickness (CT1) of the first lens (101) closest to the object side in the optical system (1000) to the largest, the light path incident on the optical system (1000) can be set, and good optical performance can be achieved at the set angle of view and focal length. By setting the center thickness (CT2) of the second lens (102) or the center thickness (CT3) of the third lens (103) closest to the aperture in the optical system (1000) to the smallest, space for the aperture arrangement can be secured, and the driving interference of the aperture can be minimized.

[0224] The central thickness of each lens may satisfy any one of the following conditions:

[0225] Condition 1: CT1 > CT2, CT3, CT4, CT5, CT6, CT7, CT8

[0226] Condition 2: CT1, CT4, CT5, CT6, CT7, CT8 > CT2 = CT3

[0227] Condition 3: CT1, CT6 > CT4 > CT2, CT3, CT5, CT7, CT8

[0228] Condition 4: CT1, CT4, CT6, CT7, CT8 > CT5 > CT2, CT3

[0229] Condition 5: CT1 > CT6 > CT2, CT3, CT4, CT5, CT7, CT8

[0230] Condition 6: CT1, CT4, CT6 > CT7 > CT2, CT3, CT5, CT8

[0231] Condition 7: CT1, CT4, CT6, CT7 > CT8 > CT2, CT3, CT5

[0232]

[0233] When describing the center spacing (CG) between the lenses, the center spacing (CG7) between the seventh lens (107) and the eighth lens (108) may be the maximum, and the center spacing (CG1) between the first and second lenses (101, 102) may be the minimum. The difference between the maximum center spacing and the minimum center spacing among the spaced lens spacings may be 1.0 mm or more, for example, in the range of 1.0 mm to 1.5 mm.

[0234] By setting the center distance (CG7) between the seventh lens (107) and the eighth lens (108) arranged closest to the image sensor (700) to the largest possible value, a gentle optical path can be formed in a short TTL, thereby forming a stable optical system. By setting the center distance (CG1) between the first lens (101) and the second lens (102) arranged on the object side of the aperture to the smallest possible value, space for diaphragm arrangement can be secured, and driving interference of the aperture can be minimized.

[0235] The center spacing between each lens can satisfy the conditions below.

[0236] Condition 1: CG2, CG3, CG4, CG5, CG6, CG7 > CG1

[0237] Condition 2: CG3, CG5, CG6, CG7 > CG2 > CG1, CG4

[0238] Condition 3: CG7 > CG3 > CG1, CG2, CG4, CG5, CG6

[0239] Condition 4: CG2, CG3, CG5, CG6, CG7 > CG4 > CG1

[0240] Condition 5: CG3, CG6, CG7 > CG5 > CG1, CG2, CG4

[0241] Condition 6: CG3, CG7 > CG6 > CG1, CG2, CG4, CG5

[0242] Condition 7: CG7 > CG1, CG2, CG3, CG4, CG5, CG6

[0243]

[0244] Regarding the effective diameter, the lens with the maximum effective diameter may be the eighth lens (108) closest to the image sensor (700). The lens with the maximum effective diameter may be a plastic lens. The lens with the maximum effective diameter may be the eighth lens (108). 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 with the maximum effective diameter may be the sixteenth surface (S16) of the eighth lens (108).

[0245] The lens having the minimum effective diameter may be any one of the plastic material lenses, and for example, the effective diameter of the third lens (103) may be the minimum within the lens unit. The lens surface having the minimum effective diameter may be the sixth surface (S6) of the third lens (103).

[0246] The effective diameter of each lens can satisfy any one of the conditions below.

[0247] Condition 1: CA_L5, CA_L6, CA_L7, CA_L8 > CA_L1 > CA_L2, CA_L3, CA_L4

[0248] Condition 2: CA_L1, CA_L5, CA_L6, CA_L7, CA_L8 > CA_L2 > CA_L3, CA_L4

[0249] Condition 3: CA_L1, CA_L2, CA_L4, CA_L5, CA_L6, CA_L7, CA_L8 > CA_L3

[0250] Condition 4: CA_L1, CA_L2, CA_L5, CA_L6, CA_L7, CA_L8 > CA_L4 > CA_L3

[0251] Condition 5: CA_L6, CA_L7, CA_L8 > CA_L5 > CA_L1, CA_L2, CA_L3, CA_L4

[0252] Condition 6: CA_L7, CA_L8 > CA_L6 > CA_L1 ,CA_L2, CA_L3, CA_L4, CA_L5

[0253] Condition 7: CA_L8 > CA_L7 > CA_L1 ,CA_L2, CA_L3, CA_L4, CA_L5, CA_L6

[0254] Condition 8: CA_L8 > CA_L1 ,CA_L2, CA_L3, CA_L4, CA_L5, CA_L6, CA_L7

[0255]

[0256] Regarding the refractive index, the refractive index of the second lens (102), the third lens (103), the fifth lens (105), and the seventh lens (107) may be the highest among the lenses and may be greater than 1.5, for example, greater than 1.6. The first lens (101), the fourth lens (104), and the sixth lens (106) may have the lowest refractive index among the lenses. For example, the refractive index of the first lens (101), the fourth lens (104), and the sixth lens (106) may be the lowest among the lenses and may be less than 1.6, for example, less than 1.55. The difference between the maximum refractive index and the minimum refractive index may be 0.1 or more.

[0257] The refractive index of each lens can satisfy any of the conditions below.

[0258] Condition 1: n2, n3, n5, n7, n8 > n1 = n4 = n6

[0259] Condition 2: n2 = n3 = n5 = n7 > n1, n4, n6, n8

[0260] Condition 3: n2, n3, n5, n7 > n8 > n1, n4, n6

[0261]

[0262] Comparing the Abbe numbers, the Abbe numbers of the second lens (102), the third lens (103), the fifth lens (105), and the seventh lens (107) are the largest among the lenses and may be 50 or more. The Abbe numbers of the first lens (101), the fourth lens (104), and the sixth lens (106) are the smallest among the lenses and may be 20 or less. The difference between the maximum Abbe number and the minimum Abbe number may be 30 or more.

[0263] The Abbe number of each lens can satisfy any of the conditions below.

[0264] Condition 1: v2, v3, v5, v7, v8 > v1 = v4 = v6

[0265] Condition 2: v1, v4, v6, v8 > v2 = v3 = v5 = v7

[0266] Condition 3: v2, v3, v5, v7 > v8 > v1, v4, v6

[0267]

[0268] The focal lengths (F2, F3, F5, F8) of the second, third, fifth, and eighth lenses (102, 103, 105, and 108) may have negative (-) signs. The second, third, fifth, and eighth lenses (102, 103, 105, and 108) may have negative (-) refractive power. The focal lengths (F1, F4, F6, F7) of the first, fourth, sixth, and seventh lenses (101, 104, 106, and 107) may have positive (+) signs. The first, fourth, sixth, and seventh lenses (101, 104, 106, and 107) may have positive (+) refractive power. The sixth and seventh lenses (106, 107) having positive (+) refractive power may be arranged on the sensor side of the fifth lens (105) having negative (-) refractive power. Through this, light incident from the object side can move away from the optical axis direction and then gather again in the optical axis direction, thereby forming a stable optical path.

[0269]

[0270] When comparing the focal lengths in absolute values, the focal length of the third lens (103) is the largest among the lenses, and may be 90 or more and 100 or less. Among the lenses, the third lens (103) made of plastic may have the largest focal length and the smallest refractive power. The focal length of the eighth lens (108) is the smallest among the lenses, and the absolute value of the focal length of the eighth lens (108) may be 3 or more and 5 or less. Among the lenses, the eighth lens (108) made of plastic may have the smallest focal length and the largest refractive power.

[0271] Among the lenses, the lens having the minimum focal length may be the eighth lens (108). The difference between the maximum focal length and the minimum focal length may be 80 or more or 100 or more. Accordingly, the optical system may have improved MTF characteristics, aberration control characteristics, resolution characteristics, etc. in the set angle of view range, and may have good optical performance in the periphery of the angle of view.

[0272] The absolute value of the focal length of each lens can satisfy any of the conditions below.

[0273] Condition 1: |f2|, |f3|, |f4|, |f5|, |f6|, |f7| > |f1| > |f8|

[0274] Condition 2: |f3| > |f2| > |f1|, |f4|, |f5|, |f6|, |f7|, |f8|

[0275] Condition 3: |f3| > |f1|, |f2|, |f4|, |f5|, |f6|, |f7|, |f8|

[0276] Condition 4: |f2|, |f3|, |f5| > |f4| > |f1|, |f6|, |f7|, |f8|

[0277] Condition 5: |f2|, |f3| > |f5| > |f1|, |f4|, |f6|, |f7|, |f8|

[0278] Condition 6: |f2|, |f3|, |f4|, |f5|, |f7| > |f6| > |f1|, |f8|

[0279] Condition 7: |f2|, |f3|, |f4|, |f5| > |f7| > |f1|, |f6|, |f8|

[0280] Condition 8: |f1|, |f2|, |f3|, |f4|, |f5|, |f6|, |f7| > |f8|

[0281]

[0282] The thickness (T1) of the first lens (101) may be minimum at the edge and maximum at the center, and the maximum thickness is in the range of 3 to 5 times the minimum thickness. The thickness (T2) of the second lens (102) may be maximum at the edge and minimum at the center, and the maximum thickness is in the range of 1 to 1.5 times the minimum thickness. The thickness (T3) of the third lens (103) may be minimum at the center and maximum at the edge, and the maximum thickness is in the range of 1.5 to 2 times the minimum thickness. The thickness (T4) of the fourth lens (104) may be maximum at the center and minimum at the edge, and the maximum thickness is in the range of 2 to 2.5 times the minimum thickness. The thickness (T5) of the fifth lens (105) may be minimum at the center and maximum at the edge, and the maximum thickness is in the range of 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 2 to 2.5 times the minimum thickness. The thickness (T7) of the seventh lens (107) may be maximum at the center and minimum at the edge, and the maximum thickness is in the range of 2 to 2.5 times the minimum thickness. The thickness (T8) of the eighth lens (108) may be minimum at the center and maximum at the edge, and the maximum thickness is in the range of 3 to 3.5 times the minimum thickness.

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

[0284] Condition 1: 3 < CT1 / ET1 < 5, 0.1 < ET1 / CT1 < 0.5

[0285] Condition 2: 0.5 < CT2 / ET2 < 1, 1 < ET2 / CT2 < 1.5

[0286] Condition 3: 0.5 < CT3 / ET3 < 1, 1.5 < ET3 / CT3 < 2

[0287] Condition 4: 2 < CT4 / ET4 < 2.5, 0.1 < ET4 / CT4 < 0.5

[0288] Condition 5: 0.5 < CT5 / ET5 < 1, 1 < ET5 / CT5 < 1.5

[0289] Condition 6: 2 < CT6 / ET6 < 2.5, 0.1 < ET6 / CT6 < 0.5

[0290] Condition 7: 2 < CT7 / ET7 < 2.5, 0.1 < ET7 / CT7 < 0.5

[0291] Condition 8: 0.1 < CT8 / ET8 < 0.5, 2 < ET8 / CT8 < 5

[0292] Condition 9: 1 < ΣCT / ΣET < 1.5, 0.5 < ΣET / ΣCT < 1

[0293]

[0294] 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 maximum in the edge and a minimum in the center. The third gap (G3) between the third and fourth lenses (103, 104) may have a minimum in the edge and a maximum in the center. The third gap (G4) between the fourth and fifth lenses (104, 105) may have a maximum in the edge and a minimum in the center. The fifth gap (G5) between the fifth and sixth lenses (105, 106) may have a maximum in the center and a minimum in the edge. The sixth gap (G6) between the sixth and seventh lenses (106, 107) may have a minimum in the center and a maximum in the edge. The seventh gap (G7) between the seventh and eighth lenses (107, 108) may be maximum at the center and minimum at the edge.

[0295]

[0296] An optical system according to a second embodiment of the invention will be described.

[0297] Referring to FIG. 9, the optical system (1100) includes a lens unit, and the lens unit may include a first lens (201) to an eighth lens (208). The first to eighth lenses (201 to 208) may be sequentially arranged along the optical axis (OA) of the optical system (1100). Light corresponding to information about an object may pass through the first lens (201) to the eighth lens (208) and a filter and be incident on the image sensor (700).

[0298] 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 positive (+) refractive power on the optical axis (OA). The first lens (201) may include a plastic material or a glass material, and may be, for example, a plastic material. At least one or both of the first surface (S1) and the second surface (S2) may be aspherical. The aspherical coefficients of the first and second surfaces (S1, S2) may be provided as S1 and S2 of L1 in FIG. 10.

[0299] 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 concave meniscus shape toward the sensor side. The first lens (201) may have a convex meniscus shape toward the object side. The first lens (201) may be made of a plastic material and may have an aspherical surface.

[0300] The refractive index (n1) of the first lens (201) can satisfy the condition of n1>1.5 or n1>1.52. When the refractive index (n1) of the first lens (201) satisfies the condition, the radius of curvature of the first and second lenses (201, 202) can be increased, and lens manufacturing can be facilitated. When 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 which case, lens manufacturing is not easy, the lens defect rate increases, and it may cause a decrease in yield. At least one or both of the first surface (S1) and the second surface (S2) of the first lens can be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0301]

[0302] The second lens (202) may be arranged second from the object side. The second lens (202) may be arranged seventh from the sensor side. The second lens (202) may be arranged between the first lens (201) and the third lens (203). The second lens (202) may have negative 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.

[0303] The third surface (S3) on the object side of the second lens (202) may be convex with respect to the optical axis (OA), and the fourth surface (S4) on the sensor side may be concave. The second lens (202) may have a concave meniscus shape toward the sensor. The second lens (202) may have a convex meniscus shape toward the object side. The second lens (202) 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. 10. At least one or both of the third surface (S3) and the fourth surface (S4) of the second lens may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0304] The aperture (Stop) may be arranged around the sensor-side fourth surface (S4) of the second lens (202). The aperture (Stop) may be arranged around the object-side fifth surface (S5) of the third lens (203). The aperture can reduce the TTL within the field of view range, and the optical system can be miniaturized. Accordingly, the yield by weight of the optical system can be prevented from decreasing, 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 60 to 90 degrees.

[0305]

[0306] The third lens (203) may be arranged third from the object side. The third lens (203) may be arranged sixth from the sensor side. The third lens (203) may be arranged between the second lens (202) and the fourth lens (204). The third lens (203) may have negative (-) refractive power on the optical axis (OA). The third lens (203) may include a plastic or glass material. For example, the third lens (203) may be provided as a plastic material.

[0307] The fifth surface (S5) on the object side of the third lens (203) with respect to the optical axis may be convex, and the sixth surface (S6) on the sensor side may be concave. The third lens (203) may have a meniscus shape in which the sensor side is concave. The third lens (203) may have a meniscus shape in which the object side is convex. The third lens (203) is made of a plastic material and may be aspherical. At least one or both of the fifth surface (S5) and the sixth surface (S6) may be aspherical. The aspherical coefficients of the fifth and sixth surfaces (S5, S6) may be provided as S1 and S2 of L3 in FIG. 10. At least one or both of the fifth surface (S5) and the sixth surface (S6) of the third lens may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0308]

[0309] The fourth lens (204) may be arranged fourth from the object side. The fourth lens (204) may be arranged fifth from the sensor side. The fourth lens (204) may be arranged between the third lens (203) and the fifth lens (205). The fourth lens (204) may have positive (+) or negative (-) refractive power on the optical axis (OA). The fourth lens (204) may have positive (+) refractive power. Unlike the refractive power of the fifth lens (205), the fourth lens (204) may have positive (+) refractive power. The fourth lens (204) may include a plastic or glass material. For example, the fourth lens (204) may be provided with a plastic material.

[0310] The seventh surface (S7) on the object side of the fourth lens (204) with respect to the optical axis may be concave, and the eighth surface (S8) on the sensor side may be convex. The fourth lens (204) may have a meniscus shape with a convex side on the sensor side. The fourth lens (204) may have a meniscus shape with a concave side on the object side. The fourth lens (204) is made of a plastic material and may have an aspherical surface. 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. 10. 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.

[0311]

[0312] The fifth lens (205) may be arranged as the fifth lens from the object side. The fifth lens (205) may be arranged as the fourth lens from the sensor side. The fifth lens (205) may be arranged between the fourth lens (204) and the sixth lens (206). The fifth lens (205) may have positive (+) or negative (-) refractive power on the optical axis (OA). The fifth lens (205) may have negative (-) refractive power. Unlike the refractive power of the fourth lens (204), the fifth lens (205) may have negative (-) refractive power. The fifth lens (205) may include a plastic or glass material. For example, the fifth lens (205) may be provided as a plastic material. The fifth lens (205) may be provided as the same material as the sixth lens (206).

[0313] 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 concave. The fifth lens (205) may have a concave meniscus shape on the sensor side. The fifth lens (205) may have a convex meniscus shape on the object side. The fifth lens (205) may be made of a plastic material and may have an aspherical surface. At least one of the ninth surface (S9) and the tenth surface (S10) may be an aspherical surface. The aspherical coefficients of the ninth and tenth surfaces (S9, S10) may be provided as S1 and S2 of L5 in FIG. 10.

[0314] The ninth surface (S9) of the fifth lens (205) may have a critical point from the optical axis (OA) to the end of the effective area. When the ninth surface (S9) has a critical point, it may be located in a range of 40% to 60%, preferably in a range of 50% to 55%, of the effective radius from the optical axis (OA). The critical point of the ninth surface (S9) may be located in a range of 1.0 mm to 2 mm, preferably in a range of 1.2 mm to 1.5 mm from the optical axis (OA).

[0315] The critical point of the ninth surface (S9) is a point where the sign of the slope value with respect to the optical axis (OA) and the direction perpendicular to the optical axis (OA) changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the slope value is 0. In addition, the critical point of the ninth surface (S9) may be a point where the slope value of the tangent line passing through the lens surface increases and then decreases, or a point where the slope value decreases and then increases.

[0316] The tenth surface (S10) of the fifth lens (205) may have a critical point from the optical axis (OA) to the end of the effective area. When the tenth surface (S10) has a critical point, it may be located in a range of 50% to 70%, preferably 55% to 60%, of the effective radius from the optical axis (OA). The critical point of the tenth surface (S10) may be located in a range of 1.0 mm to 2 mm, preferably 1.5 mm to 1.8 mm from the optical axis (OA).

[0317] The critical point of the tenth surface (S10) is a point where the sign of the slope value with respect to the optical axis (OA) and the direction perpendicular to the optical axis (OA) changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the slope value is 0. In addition, the critical point of the tenth surface (S10) may be a point where the slope value of the tangent line passing through the lens surface increases and then decreases, or a point where the slope value decreases and then increases.

[0318]

[0319] The sixth lens (206) may be arranged as the sixth lens from the object side. The sixth lens (206) may be arranged as the third lens from the sensor side. The sixth lens (206) may be arranged between the fifth lens (205) and the seventh lens (207). The sixth lens (206) may have positive (+) or negative (-) refractive power on the optical axis (OA). The sixth lens (206) may have positive (+) refractive power. The sixth lens (206) may include a plastic or glass material. For example, the sixth lens (206) may be provided as a plastic material.

[0320] The sixth lens (206) may have a convex shape on the object-side eleventh surface (S11) and a convex shape on the sensor-side twelveth surface (S12) with respect to the optical axis (OA). The sixth lens (206) may have a convex shape on both sides with respect to the optical axis (OA). At least one or both of the eleventh surface (S11) and the twelfth surface (S12) may be aspherical. The aspherical coefficients of the eleventh and twelfth surfaces (S11, S12) may be provided as S1 and S2 of L6 in FIG. 10.

[0321] The eleventh surface (S11) of the sixth lens (205) may have a critical point from the optical axis (OA) to the end of the effective area. When the eleventh surface (S11) has a critical point, it may be located in a range of 50% to 70%, preferably in a range of 60% to 70%, of the effective radius from the optical axis (OA). The critical point of the eleventh surface (S11) may be located in a range of 1.5 mm to 2.5 mm, preferably in a range of 2.0 mm to 2.3 mm from the optical axis (OA).

[0322] The critical point of the eleventh surface (S11) is a point where the sign of the slope value with respect to the optical axis (OA) and the direction perpendicular to the optical axis (OA) changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the slope value is 0. In addition, the critical point of the eleventh surface (S11) may be a point where the slope value of the tangent line passing through the lens surface increases and then decreases, or a point where the slope value decreases and then increases.

[0323] The twelfth surface (S12) of the sixth lens (205) may have 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 90% to 98%, preferably in a range of 92% to 95%, of the effective radius from the optical axis (OA). The critical point of the twelfth surface (S12) may be located in a range of 2.5 mm to 3.3 mm, preferably in a range of 3.0 mm to 3.2 mm from the optical axis (OA).

[0324] The critical point of the 12th surface (S12) is a point where the sign of the slope value with respect to the optical axis (OA) and the direction perpendicular to the optical axis (OA) changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the slope value is 0. In addition, the critical point of the 12th surface (S12) may be a point where the slope value of the tangent line passing through the lens surface increases and then decreases, or a point where the slope value decreases and then increases.

[0325]

[0326] The seventh lens (207) may be arranged as the seventh lens from the object side. The seventh lens (207) may be arranged as the second lens from the sensor side. The seventh lens (207) may be arranged between the sixth lens (206) and the eighth lens (208). The seventh lens (207) may have positive (+) refractive power on the optical axis (OA). The seventh lens (207) may include a plastic or glass material. For example, the seventh lens (207) may be provided as a plastic material.

[0327] The object-side 13th surface (S13) of the seventh lens (207) may be concave with respect to the optical axis, and the sensor-side 14th surface (S14) may be convex. The seventh lens (207) may have a meniscus shape in which the sensor side is convex. The seventh lens (207) may have a meniscus shape in which the object side is concave. The seventh lens (207) may be made of a plastic material and may be aspherical. At least one or both of the 13th surface (S13) and the 14th surface (S14) may be aspherical. The aspherical coefficients of the 13th and 14th surfaces (S13, S14) may be provided as S1 and S2 of L7 in FIG. 10. The 13th surface (S13) and the 14th surface (S14) of the seventh lens may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0328]

[0329] The eighth lens (208) may be arranged closest to the sensor side. The eighth lens (208) may be arranged farthest from the object side. The eighth lens (208) may have positive (+) or negative (-) refractive power on the optical axis (OA). The eighth lens (208) may have negative (-) refractive power. The eighth lens (208) may include a plastic or glass material. For example, the eighth lens (208) may be made of a plastic material.

[0330] The object-side 15th surface (S15) of the 8th lens (208) on the optical axis may be concave, and the sensor-side 16th surface (S16) may be concave. The 8th lens (208) may have a concave shape on both sides. At least one surface of the 15th surface (S15) and the 16th surface (S16) may be aspherical. For example, both the 15th surface (S15) and the 16th surface (S16) may be aspherical. The aspherical coefficients of the 15th and 16th surfaces (S15, S16) may be provided as S1 and S2 of L8 in FIG. 10.

[0331] The fifteenth surface (S15) of the eighth lens (208) may be provided without a critical point from the optical axis (OA) to the end of the effective area. The sixteenth surface (S16) of the eighth lens (208) may have a critical point from the optical axis (OA) to the end of the effective area. When the sixteenth surface (S16) has a critical point, it may be located in a range of 30% to 40%, preferably in a range of 35% to 38%, of the effective radius from the optical axis (OA). The critical point of the sixteenth surface (S16) may be located in a range of 1.5 mm to 2.1 mm, preferably in a range of 1.6 mm to 2.0 mm from the optical axis (OA).

[0332] The critical point of the 16th surface (S16) is a point where the sign of the slope value with respect to the optical axis (OA) and the direction perpendicular to the optical axis (OA) changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the slope value is 0. In addition, the critical point of the 16th surface (S16) may be a point where the slope value of the tangent line passing through the lens surface increases and then decreases, or a point where the slope value decreases and then increases.

[0333]

[0334] LensSurfaceRadiusThicknessndvdSemiApertureFocal length1S13.4611.0641.546856.3322.48.0084 S214.7110.07 2.377 2S315.5780.231.679519.24592.335-31.2717 S48.9350.296 2.231 Stop-0.208 2.171 3 S54.0620.231.679519.24592.076-97.6781S63.740.763 2 4S7-23.4020.8461.546856.33152.00121.4842 S8-7.9210.05 2.1 5S94.1650.2781.679519.24592.575-23.8138 S103.2230.481 2.789 6S1128.0620.7961.546856.33153.2257.9405 S12-5.0850.404 3.361 7S13-12.5630.5311.679519.24593.63619.3779 S14-6.5391.344 3.898 8S15-3.0520.41.570637.56474.086-4.1378S1610.9270.113 5.048 Cover glassS17-0.1 5.919 S18-0.7 5.957 Image -0 6.4

[0335]

[0336] Table 3 shows the surface number (Surface), radius of curvature (Radius), center thickness of each lens or distance between lens surfaces (Thickness), refractive index (Index,nd), Abbe number (Abbe,vd), effective radius (Semi Aperture), and focal length (Fcoal length) of the lens according to the second embodiment of the present invention. At this time, the unit of the radius of curvature and thickness or distance may be mm.

[0337]

[0338] Item ValueItem ValueF6.8336ET10.2403ΣIndex12.929ET20.3054ΣAbbe283.5428ET30.3459ΣCT4.3757ET40.50 02ΣCG3.6164ET50.3371CA_max10.095ET60.2908CA_min3.999ET70.2788CA_Aver5.767ET81.3693 CT_max1.0644F-number1.4CT_min0.23FOV_D82.12517CT_Aver0.546963FOV_V55.07613EPD4.881 1FOV_H70.29458BFL0.913268ImgH6.1TD7.99222SD6.331468LG1_F8.224TTL8.9055LG2_F-18.367

[0339]

[0340] Table 4 shows the items of the mathematical formulas described above in the optical system (1100) of the embodiment, including the TTL (Total track length) (mm), BFL (Back focal length), effective focal length (F) (mm), ImgH (mm), effective diameter (CA) (mm), thickness (mm), TTL (mm), TD (mm), which is the optical axis distance from the first surface (S1) to the sixteenth surface (S16), SD (mm), which is the optical axis distance from the aperture (Stop) to the sixteenth surface (S16), sum of refractive indices, sum of Abbe numbers, sum of thicknesses (mm), sum of spacings between adjacent lenses, effective diameter characteristics, diagonal angle of view (FOV_D) (Degree), vertical angle of view (FOV_V) (Degree), horizontal angle of view (FOV_H) (Degree), edge thickness (ET), F number, composite focal length (LG1_F) of the first lens group (LG1), This is about the composite focal length (LG2_F) of the second lens group (LG2).

[0341]

[0342] The center thicknesses of the first to eighth lenses (201 to 208) are represented by CT1 to CT8, the edge thicknesses at the ends of the effective areas of each lens are represented by ET1 to ET8, the center gap between two adjacent lenses is represented by CG1 to CG7, and the edge gaps between the edges of each lens are represented by EG1 to EG7. The 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).

[0343] As shown in Fig. 10, among the lenses of the lens unit in the second embodiment, the lens surfaces of the first to eighth lenses (201 to 208) may include aspherical surfaces having a 30th aspherical coefficient. For example, the first to eighth lenses (201 to 208) may include lens surfaces having a 30th aspherical coefficient. As described above, the aspherical surface having a 30th 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).

[0344] When comparing the absolute values ​​of the curvature radii of each lens, the curvature radii of the eleventh surface (S11) of the sixth lens (206) on the optical axis (OA) may be the largest among the lenses, and the curvature radii of the fifteenth surface (S15) of the eighth lens (208) 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. The curvature radii of the object-side surface of the eighth lens (208) arranged on the sensor side of the seventh lens (207) may be the smallest among the lenses.

[0345] The absolute value of the curvature radius of the first surface (S1) of the first lens (201) may be smaller 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 larger 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 larger 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 larger 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 larger than the absolute value of the curvature radius of the tenth surface (S10). The absolute value of the curvature radius of the eleventh surface (S11) of the sixth lens (206) may be greater than the absolute value of the curvature radius of the twelfth surface (S12). The absolute value of the curvature radius of the thirteenth surface (S13) of the seventh lens (207) may be greater than the absolute value of the curvature radius of the fourteenth surface (S14). The absolute value of the curvature radius of the fifteenth surface (S15) of the eighth lens (208) may be less than the absolute value of the curvature radius of the sixteenth surface (S16).

[0346] The ratio of the radius of curvature of each lens can satisfy the following conditions.

[0347] Condition 1: 0.1 < |L1R1 / L1R2| < 0.5

[0348] Condition 2: 1.5 < |L2R1 / L2R2| < 2

[0349] Condition 3: 1 < |L3R1 / L3R2| < 1.5

[0350] Condition 4: 2.5 < |L4R1 / L4R2| < 3

[0351] Condition 5: 1 < |L5R1 / L5R2| < 1.5

[0352] Condition 6: 5 < |L6R1 / L6R2| < 10

[0353] Condition 7: 1.5 < |L7R1 / L7R2| < 2

[0354] Condition 8: 0.1 < |L8R1 / L8R2| < 0.5

[0355]

[0356] When describing the central thickness of the lenses based on the optical axis, the central thickness (CT1) of the first lens (201) is the largest among the lenses, and the central thickness (CT2) of the second lens (202) and the central thickness (CT3) of the third lens are the smallest among the lenses. The difference between the maximum and minimum central thicknesses among the lenses may be in the range of 0.5 mm or more and 1 mm or less.

[0357] By setting the center thickness (CT1) of the first lens (201) closest to the object side in the optical system (1100) to the largest, the light path incident on the optical system (1100) can be set, and good optical performance can be achieved at the set angle of view and focal length. By setting the center thickness (CT2) of the second lens (202) and the center thickness (CT3) of the third lens (203) closest to the aperture in the optical system (1100) to the smallest, space for the aperture arrangement can be secured, and the driving interference of the aperture can be minimized.

[0358] The central thickness of each lens may satisfy any one of the following conditions:

[0359] Condition 1: CT1 > CT2, CT3, CT4, CT5, CT6, CT7, CT8

[0360] Condition 2: CT1, CT4, CT5, CT6, CT7, CT8 > CT2 = CT3

[0361] Condition 3: CT1 > CT4 > CT2, CT3, CT5, CT6, CT7, CT8

[0362] Condition 4: CT1, CT4, CT6, CT7, CT8 > CT5 > CT2, CT3

[0363] Condition 5: CT1, CT4 > CT6 > CT2, CT3, CT5, CT7, CT8

[0364] Condition 6: CT1, CT4, CT6 > CT7 > CT2, CT3, CT5, CT8

[0365] Condition 7: CT1, CT4, CT6, CT7 > CT8 > CT2, CT3, CT5

[0366]

[0367] When describing the center spacing (CG) between the lenses, the center spacing (CG7) between the seventh lens (207) and the eighth lens (208) may be the maximum, and the center spacing (CG4) between the fourth and fifth lenses (204, 205) may be the minimum. The difference between the maximum center spacing and the minimum center spacing among the spaced lens spacings may be 1.0 mm or more, for example, in the range of 1.0 mm to 1.5 mm.

[0368] By setting the center distance (CG7) between the seventh lens (207) and the eighth lens (208) that are arranged closest to the image sensor (700) to the largest possible value, a gentle optical path can be formed in a short TTL, thereby forming a stable optical system. By setting the center distance (CG4) between the fourth lens (204) and the fifth lens (205) to the smallest possible value, space for diaphragm arrangement can be secured, and driving interference of the diaphragm can be minimized.

[0369] The center spacing between each lens can satisfy the conditions below.

[0370] Condition 1: CG2, CG3, CG5, CG6, CG7 > CG1 > CG4

[0371] Condition 2: CG3, CG7 > CG2 > CG1, CG4, CG5, CG6

[0372] Condition 3: CG7 > CG3 > CG1, CG2, CG4, CG5, CG6

[0373] Condition 4: CG1, CG2, CG3, CG5, CG6, CG7 > CG4

[0374] Condition 5: CG2, CG3, CG7 > CG5 > CG1, CG4, CG6

[0375] Condition 6: CG2, CG3, CG5, CG7 > CG6 > CG1, CG4

[0376] Condition 7: CG7 > CG1, CG2, CG3, CG4, CG5, CG6

[0377]

[0378] Regarding the effective diameter, the lens with the maximum effective diameter may be the eighth lens (208) closest to the image sensor (700). The lens with the maximum effective diameter may be a plastic lens. The lens with the maximum effective diameter may be the eighth lens (208). 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 with the maximum effective diameter may be the sixteenth surface (S16) of the eighth lens (208).

[0379] The lens having the minimum effective diameter may be any one of the plastic material lenses, and for example, the effective diameter of the third lens (203) may be the minimum within the lens unit. The lens surface having the minimum effective diameter may be the sixth surface (S6) of the third lens (203).

[0380] The effective diameter of each lens can satisfy any one of the conditions below.

[0381] Condition 1: CA_L5, CA_L6, CA_L7, CA_L8 > CA_L1 > CA_L2, CA_L3, CA_L4

[0382] Condition 2: CA_L1, CA_L5, CA_L6, CA_L7, CA_L8 > CA_L2 > CA_L3, CA_L4

[0383] Condition 3: CA_L1, CA_L2, CA_L4, CA_L5, CA_L6, CA_L7, CA_L8 > CA_L3

[0384] Condition 4: CA_L1, CA_L2, CA_L5, CA_L6, CA_L7, CA_L8 > CA_L4 > CA_L3

[0385] Condition 5: CA_L6, CA_L7, CA_L8 > CA_L5 > CA_L1, CA_L2, CA_L3, CA_L4

[0386] Condition 6: CA_L7, CA_L8 > CA_L6 > CA_L1 ,CA_L2, CA_L3, CA_L4, CA_L5

[0387] Condition 7: CA_L8 > CA_L7 > CA_L1 ,CA_L2, CA_L3, CA_L4, CA_L5, CA_L6

[0388] Condition 8: CA_L8 > CA_L1 ,CA_L2, CA_L3, CA_L4, CA_L5, CA_L6, CA_L7

[0389]

[0390] Regarding the refractive indices, the refractive indices of the second lens (202), the third lens (203), the fifth lens (205), and the seventh lens (207) may be the largest among the lenses and may be greater than 1.5, for example, greater than 1.6. The first lens (201), the fourth lens (204), and the sixth lens (206) may have the smallest refractive indices among the lenses. For example, the refractive indices of the first lens (201), the fourth lens (204), and the sixth lens (206) 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 0.1 or more.

[0391] The refractive index of each lens can satisfy any of the conditions below.

[0392] Condition 1: n2, n3, n5, n7, n8 > n1 = n4 = n6

[0393] Condition 2: n2 = n3 = n5 = n7 > n1, n4, n6, n8

[0394] Condition 3: n2, n3, n5, n7 > n8 > n1, n4, n6

[0395]

[0396] Comparing the Abbe numbers, the Abbe numbers of the second lens (202), the third lens (203), the fifth lens (205), and the seventh lens (207) are the largest among the lenses and may be 50 or more. The Abbe numbers of the first lens (201), the fourth lens (204), and the sixth lens (206) are the smallest among the lenses and may be 20 or less. The difference between the maximum Abbe number and the minimum Abbe number may be 30 or more.

[0397] The Abbe number of each lens can satisfy any of the conditions below.

[0398] Condition 1: v2, v3, v5, v7, v8 > v1 = v4 = v6

[0399] Condition 2: v1, v4, v6, v8 > v2 = v3 = v5 = v7

[0400] Condition 3: v2, v3, v5, v7 > v8 > v1, v4, v6

[0401]

[0402] The focal lengths (F2, F3, F5, F8) of the second, third, fifth, and eighth lenses (202, 203, 205, and 208) may have negative (-) signs. The second, third, fifth, and eighth lenses (202, 203, 205, and 208) may have negative (-) refractive power. The focal lengths (F1, F4, F6, F7) of the first, fourth, sixth, and seventh lenses (201, 204, 206, and 207) may have positive (+) signs. The first, fourth, sixth, and seventh lenses (201, 204, 206, and 207) may have positive (+) refractive power. The sixth and seventh lenses (206, and 207) having positive (+) refractive power may be arranged on the sensor side of the fifth lens (205) having negative (-) refractive power. Through this, light incident from the object side can move away from the optical axis direction and then gather again in the optical axis direction, thereby forming a stable optical path.

[0403]

[0404] When comparing the focal lengths in absolute values, the focal length of the third lens (203) is the largest among the lenses, and may be 90 or more and 100 or less. Among the lenses, the third lens (203) made of plastic may have the largest focal length and the smallest refractive power. The focal length of the eighth lens (208) is the smallest among the lenses, and the absolute value of the focal length of the eighth lens (208) may be 3 or more and 5 or less. Among the lenses, the eighth lens (208) made of plastic may have the smallest focal length and the largest refractive power.

[0405] Among the lenses, the lens having the minimum focal length may be the eighth lens (208). The difference between the maximum focal length and the minimum focal length may be 80 or more or 100 or more. Accordingly, the optical system may have improved MTF characteristics, aberration control characteristics, resolution characteristics, etc. in the set field of view range, and may have good optical performance in the periphery of the field of view.

[0406] The absolute value of the focal length of each lens can satisfy any of the conditions below.

[0407] Condition 1: |f2|, |f3|, |f4|, |f5|, |f7| > |f1| > |f6|, |f8|

[0408] Condition 2: |f3| > |f2| > |f1|, |f4|, |f5|, |f6|, |f7|, |f8|

[0409] Condition 3: |f3| > |f1|, |f2|, |f4|, |f5|, |f6|, |f7|, |f8|

[0410] Condition 4: |f2|, |f3|, |f5| > |f4| > |f1|, |f6|, |f7|, |f8|

[0411] Condition 5: |f2|, |f3| > |f5| > |f1|, |f4|, |f6|, |f7|, |f8|

[0412] Condition 6: |f1|, |f2|, |f3|, |f4|, |f5|, |f7| > |f6| > |f8|

[0413] Condition 7: |f2|, |f3|, |f4|, |f5| > |f7| > |f1|, |f6|, |f8|

[0414] Condition 8: |f1|, |f2|, |f3|, |f4|, |f5|, |f6|, |f7| > |f8|

[0415]

[0416] The thickness (T1) of the first lens (201) may be minimum at the edge and maximum at the center, and the maximum thickness is in the range of 3 to 5 times the minimum thickness. The thickness (T2) of the second lens (202) may be maximum at the edge and minimum at the center, and the maximum thickness is in the range of 1 to 1.5 times the minimum thickness. The thickness (T3) of the third lens (203) may be minimum at the center and maximum at the edge, and the maximum thickness is in the range of 1.5 to 2 times the minimum thickness. The thickness (T4) of the fourth lens (204) may be maximum at the center and minimum at the edge, and the maximum thickness is in the range of 1.5 to 2 times the minimum thickness. The thickness (T5) of the fifth lens (205) may be minimum at the center and maximum at the edge, and the maximum thickness is in the range of 1 to 1.5 times the minimum thickness. The thickness (T6) of the sixth lens (206) may be maximum at the center and minimum at the edge, and the maximum thickness is in the range of 2.5 to 3 times the minimum thickness. The thickness (T7) of the seventh lens (207) may be maximum at the center and minimum at the edge, and the maximum thickness is in the range of 1.5 to 2 times the minimum thickness. The thickness (T8) of the eighth lens (208) may be minimum at the center and maximum at the edge, and the maximum thickness is in the range of 3 to 3.5 times the minimum thickness.

[0417] The thickness of each lens can satisfy any of the conditions below.

[0418] Condition 1: 3 < CT1 / ET1 < 5, 0.1 < ET1 / CT1 < 0.5

[0419] Condition 2: 0.5 < CT2 / ET2 < 1, 1 < ET2 / CT2 < 1.5

[0420] Condition 3: 0.5 < CT3 / ET3 < 1, 1.5 < ET3 / CT3 < 2

[0421] Condition 4: 1.5 < CT4 / ET4 < 2, 0.5 < ET4 / CT4 < 1

[0422] Condition 5: 0.5 < CT5 / ET5 < 1, 1 < ET5 / CT5 < 1.5

[0423] Condition 6: 2.5 < CT6 / ET6 < 3, 0.1 < ET6 / CT6 < 0.5

[0424] Condition 7: 1.5 < CT7 / ET7 < 2, 0.5 < ET7 / CT7 < 1

[0425] Condition 8: 0.1 < CT8 / ET8 < 0.5, 2 < ET8 / CT8 < 5

[0426] Condition 9: 1 < ΣCT / ΣET < 1.5, 0.5 < ΣET / ΣCT < 1

[0427]

[0428] Among the gaps (G1-G7) between the lenses, the first gap (G1) between the first and second lenses (201, 202) may have a minimum in the center and a maximum in the edge. The second gap (G2) between the second and third lenses (202, 203) may have a maximum in the edge and a minimum in the center. The third gap (G3) between the third and fourth lenses (203, 204) may have a minimum in the edge and a maximum in the center. The third gap (G4) between the fourth and fifth lenses (204, 205) may have a maximum in the edge and a minimum in the center. The fifth gap (G5) between the fifth and sixth lenses (205, 206) may have a minimum in the center and a maximum in the edge. The sixth gap (G6) between the sixth and seventh lenses (206, 207) may have a minimum in the center and a maximum in the edge. The seventh gap (G7) between the seventh and eighth lenses (207, 208) may be maximum at the center and minimum at the edge.

[0429]

[0430] An optical system according to a third embodiment of the invention will be described.

[0431] Referring to FIG. 17, the optical system (1200) includes a lens unit, and the lens unit may include a first lens (301) to a seventh lens (307). The first to seventh lenses (301 to 307) may be sequentially arranged along the optical axis (OA) of the optical system (1200). Light corresponding to information about an object may pass through the first lens (301) to the seventh lens (307) and a filter (800) and be incident on the image sensor (700).

[0432] 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 positive (+) refractive power on the optical axis (OA). The first lens (301) may include a plastic material or a glass material, and may be, for example, a plastic material. At least one or both of the first surface (S1) and the second surface (S2) may be aspherical. The aspherical coefficients of the first and second surfaces (S1, S2) may be provided as S1 and S2 of L2 of FIG. 18.

[0433] 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 concave meniscus shape toward the sensor side. The first lens (301) may have a convex meniscus shape toward the object side. The first lens (301) may be made of a plastic material and may have an aspherical surface.

[0434] The refractive index (n1) of the first lens (301) can satisfy the condition of n1>1.5 or n1>1.52. When the refractive index (n1) of the first lens (301) satisfies the condition, the radius of curvature of the first and second lenses (301, 302) can be increased, and lens manufacturing can be facilitated. When 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.

[0435] The first surface (S1) of the first lens (301) may be provided without a critical point from the optical axis (OA) to the end of the effective area. The second surface (S2) of the first lens (301) may have a critical point from the optical axis (OA) to the end of the effective area. When the second surface (S2) has a critical point, it may be located in a range of 70% to 90%, preferably in a range of 80% to 85%, of the effective radius from the optical axis (OA). The critical point of the second surface (S2) may be located in a range of 1.0 mm to 2 mm, preferably in a range of 1.3 mm to 1.8 mm from the optical axis (OA).

[0436] The critical point of the second surface (S2) is a point where the sign of the slope value with respect to the optical axis (OA) and the direction perpendicular to the optical axis (OA) changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the slope value is 0. In addition, the critical point of the second surface (S2) may be a point where the slope value of the tangent line passing through the lens surface increases and then decreases, or a point where the slope value decreases and then increases.

[0437]

[0438] The second lens (302) may be arranged second from the object side. The second lens (302) may be arranged sixth 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 negative (-) 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.

[0439] The third surface (S3) on the object side of the second lens (302) with respect to the optical axis (OA) may be convex, and the fourth surface (S4) on the sensor side may be concave. The second lens (302) may have a concave meniscus shape toward the sensor side. The second lens (302) may have a convex meniscus shape toward the object side. The second lens (302) 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. 18.

[0440] At least one or both of the third surface (S3) and the fourth surface (S4) of the second lens (302) can be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0441] 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 40 to 60 degrees.

[0442]

[0443] The third lens (303) may be arranged third from the object side. The third lens (303) may be arranged fifth 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 plastic material.

[0444] The fifth surface (S5) on the object side of the third lens (303) with respect to the optical axis may be convex, and the sixth surface (S6) on the sensor side may be concave. The third lens (303) may have a meniscus shape in which the sensor side is concave. The third lens (303) may have a meniscus shape in which the object side is convex. The third lens (303) may be made of a plastic material and may be aspherical. At least one or both of the fifth surface (S5) and the sixth surface (S6) may be aspherical. The aspherical coefficients of the fifth and sixth surfaces (S5, S6) may be provided as S1 and S2 of L3 in FIG. 18.

[0445] The fifth surface (S5) of the third lens (303) may have a critical point from the optical axis (OA) to the end of the effective area. When the fifth surface (S5) has a critical point, it may be located in a range of 50% to 70%, preferably 55% to 60%, of the effective radius from the optical axis (OA). The critical point of the fifth surface (S5) may be located in a range of 0.5 mm to 2 mm, preferably 0.8 mm to 1.3 mm from the optical axis (OA).

[0446] The critical point of the fifth surface (S5) is a point where the sign of the slope value with respect to the optical axis (OA) and the direction perpendicular to the optical axis (OA) changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the slope value is 0. In addition, the critical point of the fifth surface (S5) may be a point where the slope value of the tangent line passing through the lens surface increases and then decreases, or a point where the slope value decreases and then increases.

[0447] The sixth surface (S6) of the third lens (303) may have a critical point from the optical axis (OA) to the end of the effective area. When the sixth surface (S6) has a critical point, it may be located in a range of 20% to 40%, preferably in a range of 30% to 38%, of the effective radius from the optical axis (OA). The critical point of the sixth surface (S6) may be located in a range of 0.5 mm to 1.5 mm, preferably in a range of 0.5 mm to 1.2 mm from the optical axis (OA).

[0448] The critical point of the sixth surface (S6) is a point where the sign of the slope value with respect to the optical axis (OA) and the direction perpendicular to the optical axis (OA) changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the slope value is 0. In addition, the critical point of the sixth surface (S6) may be a point where the slope value of the tangent line passing through the lens surface increases and then decreases, or a point where the slope value decreases and then increases.

[0449]

[0450] The fourth lens (304) may be arranged fourth from the object side. The fourth lens (304) may be arranged fourth 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. Unlike the refractive power of the fifth lens (305), 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 with a plastic material.

[0451] The seventh surface (S7) on the object side of the fourth lens (304) with respect to the optical axis may be convex, and the eighth surface (S8) on the sensor side may be concave. The fourth lens (304) may have a meniscus shape in which the sensor side is concave. The fourth lens (304) may have a meniscus shape in which the object side is convex. The fourth lens (304) is made of a plastic material and may have an aspherical surface. 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. 18. The seventh surface (S7) of the fourth lens (304) may have a critical point from the optical axis (OA) to the end of the effective area. When the seventh surface (S7) has a critical point, it may be located in a range of 25% to 45%, preferably in a range of 30% to 35%, of the effective radius from the optical axis (OA). The critical point of the seventh surface (S7) may be located in a range of 0.5 mm to 1.5 mm, preferably in a range of 0.5 mm to 1.2 mm from the optical axis (OA).

[0452] The critical point of the seventh surface (S7) is a point where the sign of the slope value with respect to the optical axis (OA) and the direction perpendicular to the optical axis (OA) changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the slope value is 0. In addition, the critical point of the seventh surface (S7) may be a point where the slope value of the tangent line passing through the lens surface increases and then decreases, or a point where the slope value decreases and then increases.

[0453] The eighth surface (S8) of the fourth lens (304) may have a critical point from the optical axis (OA) to the end of the effective area. When the eighth surface (S8) has a critical point, it may be located in a range of 35% to 55%, preferably in a range of 40% to 45%, of the effective radius from the optical axis (OA). The critical point of the eighth surface (S8) may be located in a range of 0.5 mm to 1.5 mm, preferably in a range of 0.8 mm to 1.2 mm from the optical axis (OA).

[0454] The critical point of the eighth surface (S8) is a point where the sign of the slope value with respect to the optical axis (OA) and the direction perpendicular to the optical axis (OA) changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the slope value is 0. In addition, the critical point of the eighth surface (S8) may be a point where the slope value of the tangent line passing through the lens surface increases and then decreases, or a point where the slope value decreases and then increases.

[0455]

[0456] The fifth lens (305) may be arranged fifth from the object side. The fifth lens (305) may be arranged third 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. Unlike the refractive power of the fourth lens (304), 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 with a plastic material. The fifth lens (305) may be provided with the same material as the sixth lens (306).

[0457] With respect to the optical axis (OA), the ninth surface (S9) on the object side of the fifth lens (305) may be concave, and the tenth surface (S10) on the sensor side may be convex. The fifth lens (305) may have a meniscus shape in which the sensor side is convex. The fifth lens (305) may have a meniscus shape in which the object side is concave. The fifth lens (305) may be made of a plastic material and may have an aspherical surface. At least one of the ninth surface (S9) and the tenth surface (S10) may be an aspherical surface. The aspherical coefficients of the ninth and tenth surfaces (S9, S10) may be provided as S1 and S2 of L5 in FIG. 18. At least one or both of the ninth surface (S9) and the tenth surface (S10) of the fifth lens (305) may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0458]

[0459] The sixth lens (306) may be arranged as the sixth lens from the object side. The sixth lens (306) may be arranged as the second lens from the sensor side. The sixth lens (306) may be arranged between the fifth lens (305) and the seventh lens (307). The sixth lens (306) may have positive (+) or negative (-) refractive power on the optical axis (OA). The sixth lens (306) may have negative (-) refractive power. The sixth lens (306) may include a plastic or glass material. For example, the sixth lens (306) may be provided as a plastic material.

[0460] The object-side eleventh surface (S11) of the sixth lens (306) with respect to the optical axis may be convex, and the sensor-side twelfth surface (S12) may be concave. The sixth lens (306) may have a concave meniscus shape on the sensor side. The sixth lens (306) may have a convex meniscus shape on the object side. 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. 18.

[0461] The eleventh surface (S11) of the sixth lens (306) may have a critical point from the optical axis (OA) to the end of the effective area. When the eleventh surface (S11) has a critical point, it may be located in a range of 40% to 60%, preferably in a range of 45% to 55%, of the effective radius from the optical axis (OA). The critical point of the eleventh surface (S11) may be located in a range of 1.0 mm to 2.5 mm, preferably in a range of 1.5 mm to 2.0 mm from the optical axis (OA).

[0462] The critical point of the eleventh surface (S11) is a point where the sign of the slope value with respect to the optical axis (OA) and the direction perpendicular to the optical axis (OA) changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the slope value is 0. In addition, the critical point of the eleventh surface (S11) may be a point where the slope value of the tangent line passing through the lens surface increases and then decreases, or a point where the slope value decreases and then increases.

[0463] The twelfth surface (S12) of the sixth lens (306) may have 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 40% to 60%, preferably 45% to 55%, of the effective radius from the optical axis (OA). The critical point of the eleventh surface (S11) may be located in a range of 1.5 mm to 2.5 mm, preferably 1.8 mm to 2.3 mm from the optical axis (OA).

[0464] The critical point of the 12th surface (S12) is a point where the sign of the slope value with respect to the optical axis (OA) and the direction perpendicular to the optical axis (OA) changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the slope value is 0. In addition, the critical point of the 12th surface (S12) may be a point where the slope value of the tangent line passing through the lens surface increases and then decreases, or a point where the slope value decreases and then increases.

[0465]

[0466] The seventh lens (307) may be arranged closest to the sensor side. The seventh lens (307) may be arranged farthest from the object side. The seventh lens (307) may have positive (+) or negative (-) refractive power on the optical axis (OA). The seventh lens (307) may have negative (-) refractive power. The seventh lens (307) may include a plastic or glass material. For example, the seventh lens (307) may be made of a plastic material.

[0467] The object-side 13th surface (S13) of the seventh lens (307) on the optical axis may be concave, and the sensor-side 14th surface (S14) may be concave. The seventh lens (307) may have a concave shape on both sides. At least one of the 13th surface (S13) and the 14th surface (S14) may be aspherical. For example, both the 13th surface (S13) and the 14th surface (S14) may be aspherical. The aspherical coefficients of the 13th and 14th surfaces (S13, S14) may be provided as S1 and S2 of L8 in FIG. 18.

[0468] The 13th surface (S13) of the seventh lens (307) may be provided without a critical point from the optical axis (OA) to the end of the effective area. The 14th surface (S14) of the seventh lens (307) may have a critical point from the optical axis (OA) to the end of the effective area. When the 14th surface (S14) has a critical point, it may be located in a range of 35% to 55%, preferably in a range of 38% to 45%, of the effective radius from the optical axis (OA). The critical point of the 14th surface (S14) may be located in a range of 1.5 mm to 2.1 mm, preferably in a range of 1.6 mm to 2.0 mm from the optical axis (OA).

[0469] The critical point of the 14th surface (S14) is a point where the sign of the slope value with respect to the optical axis (OA) and the direction perpendicular to the optical axis (OA) changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the slope value is 0. In addition, the critical point of the 14th surface (S14) may be a point where the slope value of the tangent line passing through the lens surface increases and then decreases, or a point where the slope value decreases and then increases.

[0470]

[0471] LensSurfaceRadiusThicknessndvdSemiApertureFocal length1S13.3920.8971.545956.09481.9007.4983 S217.9360.116 1.842 2S312.6780.3001.667120.34841.788-30.3712 S47.7240.405 1.681 Stop-0.544 1.622 3 S515.2300.6311.545956.09481.75046.9375S636.9980.298 1.975 4S713.2780.3481.667120.34842.136-47.6645 S89.2680.379 2.395 5S9-6.1800.8451.545956.09482.6008.4562 S10-2.7700.050 2.914 6S116.0350.8741.667120.34843.253-52.7237 S124.8521.239 4.024 7S13-42.5250.6781.545956.09484.567-6.5872 S143.9500.415 5.135 Cover glassS17-0.000 6.220 S18 0.7 6.300 Image 0

[0472]

[0473] Table 6 shows the surface number (Surface), radius of curvature (Radius), center thickness of each lens or distance between lens surfaces (Thickness), refractive index (Index,nd), Abbe number (Abbe,vd), effective radius (Semi Aperture), and focal length (Fcoal length) of the lens according to the third embodiment of the present invention. At this time, the unit of the radius of curvature and thickness or distance may be mm.

[0474]

[0475] Item ValueItem ValueF6.78ET10.35ΣIndex11.1849ET20.4065ΣAbbe285.4244ET30.3546ΣCT4.5735ET40.4954 ΣCG3.0318ET50.3679CA_max9.701514ET61.1241CA_min3.468765ET71.1521CA_Aver5.422801F -number1.7842CT_max0.8971FOV_D86.01281CT_min0.3FOV_V55.8094CT_Aver0.653357FOV_H5 5.8094EPD6.78ImgH6.15BFL1.094691SD5.887156TD7.605309TTL8.7LG1_F8.138LG2_F-28.878

[0476]

[0477] Table 7 shows the items of the mathematical formulas described above in the optical system (1200) of the embodiment, including the TTL (Total track length) (mm), BFL (Back focal length), effective focal length (F) (mm), ImgH (mm), effective diameter (CA) (mm), thickness (mm), TTL (mm), TD (mm), which is the optical axis distance from the first surface (S1) to the fourteenth surface (S14), SD (mm), which is the optical axis distance from the aperture (Stop) to the fourteenth surface (S14), sum of refractive indices, sum of Abbe numbers, sum of thicknesses (mm), sum of spacings between adjacent lenses, effective diameter characteristics, diagonal angle of view (FOV_D) (Degree), vertical angle of view (FOV_V) (Degree), horizontal angle of view (FOV_H) (Degree), edge thickness (ET), F number, composite focal length (LG1_F) of the first lens group (LG1), This is about the composite focal length (LG2_F) of the second lens group (LG2).

[0478] The center thicknesses of the first to seventh lenses (301 to 307) are represented by CT1 to CT7, the edge thicknesses at the ends of the effective areas of each lens are represented by ET1 to ET7, the center gap between two adjacent lenses is represented by CG1 to CG6, and the edge gaps between the edges of each lens are represented by EG1 to EG7. 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 (301) to the upper surface of the image sensor (700).

[0479] As shown in Fig. 17, among the lenses of the lens unit in the third embodiment, the lens surfaces of the first to seventh lenses (301 to 307) may include aspherical surfaces having a 30th-order aspherical coefficient. For example, the first to seventh lenses (301 to 307) 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).

[0480] When comparing the absolute values ​​of the curvature radii of each lens, the curvature radii of the thirteenth surface (S13) of the seventh lens (307) 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 10 times or more, for example, 10 to 20 times. The curvature radii of the sensor-side surface of the fifth lens (305) may be the smallest among the lenses.

[0481] The absolute value of the curvature radius of the first surface (S1) of the first lens (301) may be smaller 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 larger 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 smaller 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 larger 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 larger 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). The absolute value of the radius of curvature of the thirteenth surface (S13) of the seventh lens (307) may be greater than the absolute value of the radius of curvature of the fourteenth surface (S14).

[0482] The ratio of the radius of curvature of each lens can satisfy the following conditions.

[0483] Condition 1: 0.1 < |L1R1 / L1R2| < 0.5

[0484] Condition 2: 1.5 < |L2R1 / L2R2| < 2

[0485] Condition 3: 0.1 < |L3R1 / L3R2| < 0.5

[0486] Condition 4: 1 < |L4R1 / L4R2| < 1.5

[0487] Condition 5: 2 < |L5R1 / L5R2| < 2.5

[0488] Condition 6: 1 < |L6R1 / L6R2| < 1.5

[0489] Condition 7: 5 < |L7R1 / L7R2| < 15

[0490]

[0491] When describing the central thickness of the lenses based on the optical axis, the central thickness (CT1) of the first lens (301) is the largest among the lenses, and the central thickness (CT2) of the second lens (302) is the smallest among the lenses. The difference between the maximum and minimum central thicknesses among the lenses may be in the range of 0.5 mm or more and 1 mm or less.

[0492] By setting the center thickness (CT1) of the first lens (301) closest to the object side in the optical system (1200) to the largest, the light path incident on the optical system (1200) is set, and good optical performance can be achieved at the set angle of view and focal length. The center thickness (CT1) of the first lens (301) is set to be larger than the center distance between the sixth lens (306) and seventh lens (307), which have the largest center distance among the distances between adjacent lenses, so that a gentle light path can be formed at a short TTL, thereby forming a stable optical system.

[0493] By setting the central thickness (CT2) of the second lens (302) positioned closest to the aperture in the optical system (1200) to the smallest possible value, space for the aperture arrangement can be secured and interference with the aperture operation can be minimized. The central thickness of each lens can satisfy any one of the conditions below.

[0494] Condition 1: CT1 > CT2, CT3, CT4, CT5, CT6, CT7

[0495] Condition 2: CT1, CT3, CT4, CT5, CT6, CT7 > CT2

[0496] Condition 3: CT1, CT5, CT6, CT7 > CT3 > CT2, CT4

[0497] Condition 4: CT1, CT3, CT5, CT6, CT7 > CT4 > CT2

[0498] Condition 5: CT1, CT6 > CT5 > CT2, CT3, CT4, CT7

[0499] Condition 6: CT1 > CT6 > CT2, CT3, CT4, CT5, CT7

[0500] Condition 7: CT1, CT5, CT6 > CT7 > CT2, CT3, CT4

[0501]

[0502] When describing the center spacing (CG) between the lenses, the center spacing (CG6) between the sixth lens (306) and the seventh lens (307) may be the maximum, and the center spacing (CG5) between the fifth and sixth lenses (305, 306) may be the minimum. The difference between the maximum center spacing and the minimum center spacing among the spaced lens spacings may be 0.5 mm or more, for example, in the range of 0.5 mm to 1.0 mm.

[0503] By setting the center distance (CG6) between the sixth lens (306) and the seventh lens (307) that are arranged closest to the image sensor (700) to the largest possible value, a gentle optical path can be formed in a short TTL, thereby forming a stable optical system. By setting the center distance (CG5) between the fifth lens (305) and the sixth lens (306) to the smallest possible value, space for diaphragm arrangement can be secured, and driving interference of the diaphragm can be minimized.

[0504] By setting the distance between the second lens (302) and the third lens (303) to be greater than the center thickness of the first lens (301), a space for arranging an aperture between the second lens (302) and the third lens (303) can be secured, and driving interference of the aperture can be minimized.

[0505] The center spacing between each lens can satisfy the conditions below.

[0506] Condition 1: CG2, CG3, CG4, CG6 > CG1 > CG5

[0507] Condition 2: CG6 > CG2 > CG1, CG3, CG4, CG5

[0508] Condition 3: CG2, CG4, CG6 > CG3 > CG1, CG5

[0509] Condition 4: CG2, CG6 > CG4 > CG1, CG3, CG5

[0510] Condition 5: CG1, CG2, CG3, CG4, CG6 > CG5

[0511] Condition 6: CG6 > CG1, CG2, CG3, CG4, CG5

[0512]

[0513] Regarding the effective diameter, the lens with the maximum effective diameter may be the seventh lens (307) closest to the image sensor (700). The lens with the maximum effective diameter may be a plastic lens. 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 with the maximum effective diameter may be the fourteenth surface (S14) of the seventh lens (307).

[0514] The lens having the minimum effective diameter may be any one of the plastic material lenses, and for example, the effective diameter of the second lens (302) may be the minimum within the lens unit. The lens surface having the minimum effective diameter may be the fifth surface (S5) of the third lens (303).

[0515] The effective diameter of each lens can satisfy any one of the conditions below.

[0516] Condition 1: CA_L4, CA_L5, CA_L6, CA_L7 > CA_L1 > CA_L2, CA_L3

[0517] Condition 2: CA_L1, CA_L3, CA_L4, CA_L5, CA_L6, CA_L7 > CA_L2

[0518] Condition 3: CA_L1, CA_L4, CA_L5, CA_L6, CA_L7 > CA_L3 > CA_L2

[0519] Condition 4: CA_L5, CA_L6, CA_L7 > CA_L4 > CA_L1, CA_L2, CA_L3

[0520] Condition 5: CA_L6, CA_L7 > CA_L5 > CA_L1, CA_L2, CA_L3, CA_L4

[0521] Condition 6: CA_L7 > CA_L6 > CA_L1, CA_L2, CA_L3, CA_L4, CA_L5

[0522] Condition 7: CA_L7 > CA_L1, CA_L2, CA_L3, CA_L4, CA_L5, CA_L6

[0523]

[0524] Regarding the refractive index, the refractive index of the second lens (302), the fourth lens (304), and the sixth lens (306) may be the highest among the lenses and may be greater than 1.5, for example, greater than 1.6. The first lens (301), the third lens (303), the fifth lens (305), and the seventh lens (307) may have the lowest refractive index among the lenses. For example, the refractive index of the first lens (301), the third lens (303), the fifth lens (305), and the seventh lens (307) may be the lowest among the lenses and may be less than 1.6, for example, less than 1.55. The difference between the maximum refractive index and the minimum refractive index may be 0.1 or more.

[0525] The refractive index of each lens can satisfy any of the conditions below.

[0526] Condition 1: n2, n4, n6 > n1 = n3 = n5 = n7

[0527] Condition 2: n1, n3, n5, n7 > n2 = n4 = n6

[0528]

[0529] Comparing the Abbe numbers, the Abbe numbers of the first lens (301), the third lens (303), the fifth lens (305), and the seventh lens (307) are the largest among the lenses and may be 50 or more. The Abbe numbers of the second lens (302), the fourth lens (304), and the sixth lens (306) are the smallest among the lenses and may be 30 or less. The difference between the maximum Abbe number and the minimum Abbe number may be 30 or more.

[0530] The Abbe number of each lens can satisfy any of the conditions below.

[0531] Condition 1: v1 = v3 = v5 = v7 > v2, v4, v6

[0532] Condition 2: v1, v3, v5, v7 > v2 = v4 = v6

[0533]

[0534] The focal lengths (F2, F4, F6, F7) of the second, fourth, sixth, and seventh lenses (302, 304, 306, and 307) may have negative (-) signs. The second, fourth, sixth, and seventh lenses (302, 304, 306, and 307) may have negative (-) refractive power. The focal lengths (F1, F3, and F5) of the first, third, and fifth lenses (301, 303, and 305) may have positive (+) signs. The first, third, and fifth lenses (301, 303, and 305) may have positive (+) refractive power. The sixth and seventh lenses (306, 307) having negative (-) refractive power may be arranged on the sensor side of the fifth lens (305) having positive (+) refractive power. Through this, light incident from the object side can move closer to the optical axis and then move away from the optical axis again, thereby forming a stable optical path.

[0535]

[0536] When comparing the focal lengths in absolute values, the focal length of the sixth lens (306) is the largest among the lenses, and may be 50 or more and 70 or less. Among the lenses, the sixth lens (306) made of plastic may have the largest focal length and the smallest refractive power. The focal length of the seventh lens (307) is the smallest among the lenses, and the absolute value of the focal length of the seventh lens (307) may be 5 or more and 10 or less. Among the lenses, the seventh lens (307) made of plastic may have the smallest focal length and the largest refractive power.

[0537] Among the lenses, the lens having the minimum focal length may be the seventh lens (307). The difference between the maximum focal length and the minimum focal length may be 30 or more or 40 or more. Accordingly, the optical system may have improved MTF characteristics, aberration control characteristics, resolution characteristics, etc. in the set angle of view range, and may have good optical performance in the periphery of the angle of view.

[0538] The absolute value of the focal length of each lens can satisfy any of the conditions below.

[0539] Condition 1: |f2|, |f3|, |f4|, |f5|, |f6| > |f1| > |f7|

[0540] Condition 2: |f3|, |f4|, |f6| > |f2| > |f1|, |f5|, |f7|

[0541] Condition 3: |f4|, |f6| > |f3| > |f1|, |f2|, |f5|, |f7|

[0542] Condition 4: |f6| > |f4| > |f1|, |f2|, |f3|, |f5|, |f7|

[0543] Condition 5: |f2|, |f3|, |f4|, |f6| > |f5| > |f1|, |f7|

[0544] Condition 6: |f6| > |f1|, |f2|, |f3|, |f4|, |f5|, |f7|

[0545] Condition 7: |f1|, |f2|, |f3|, |f4|, |f5|, |f6| > |f7|

[0546]

[0547] The thickness (T1) of the first lens (301) may be minimum at the edge and maximum at the center, and the maximum thickness is in the range of 2 to 3 times the minimum thickness. The thickness (T2) of the second lens (302) may be maximum at the edge and minimum at the center, and the maximum thickness is in the range of 1 to 1.5 times the minimum thickness. The thickness (T3) of the third lens (303) may be maximum at the center and minimum at the edge, and the maximum thickness is in the range of 1.5 to 2 times the minimum thickness. The thickness (T4) of the fourth lens (304) may be minimum at the center and maximum at the edge, and the maximum thickness is in the range of 1 to 1.5 times the minimum thickness. The thickness (T5) of the fifth lens (305) may be maximum at the center and minimum at the edge, and the maximum thickness is in the range of 2 to 2.5 times the minimum thickness. The thickness (T6) of the sixth lens (306) may be minimum at the center and maximum at the edge, and the maximum thickness is in the range of 1 to 1.5 times the minimum thickness. The thickness (T7) of the seventh lens (307) may be minimum at the center and maximum at the edge, and the maximum thickness is in the range of 1.5 to 2 times the minimum thickness.

[0548] The thickness of each lens can satisfy any of the conditions below.

[0549] Condition 1: 2.5 < CT1 / ET1 < 3, 0.1 < ET1 / CT1 < 0.5

[0550] Condition 2: 0.5 < CT2 / ET2 < 1, 1 < ET2 / CT2 < 1.5

[0551] Condition 3: 1.5 < CT3 / ET3 < 2, 0.5 < ET3 / CT3 < 1

[0552] Condition 4: 0.5 < CT4 / ET4 < 1, 1 < ET4 / CT4 < 1.5

[0553] Condition 5: 2.0 < CT5 / ET5 < 2.5, 0.1 < ET5 / CT5 < 0.5

[0554] Condition 6: 0.5 < CT6 / ET6 < 1, 1 < ET6 / CT6 < 1.5

[0555] Condition 7: 0.5 < CT7 / ET7 < 1, 1.5 < ET7 / CT7 < 2

[0556] Condition 9: 1 < ΣCT / ΣET < 1.5, 0.5 < ΣET / ΣCT < 1

[0557]

[0558] Among the gaps (G1-G6) between the lenses, the first gap (G1) between the first and second lenses (301, 302) may have a minimum in the center and a maximum in the edge. The second gap (G2) between the second and third lenses (302, 303) may have a minimum in the edge and a maximum in the center. 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 minimum in the edge and a maximum in the center. The fifth gap (G5) between the fifth and sixth lenses (305, 306) may have a minimum in the center and a maximum in the edge. The sixth gap (G6) between the sixth and seventh lenses (306, 307) may have a maximum in the center and a minimum in the edge.

[0559]

[0560] An optical system according to a fourth embodiment of the invention will be described.

[0561] Referring to FIG. 25, the optical system (1300) includes a lens unit, and the lens unit may include a first lens (401) to a seventh lens (407). The first to seventh lenses (401 to 407) may be sequentially arranged along the optical axis (OA) of the optical system (1300). Light corresponding to information about an object may pass through the first lens (401) to the seventh lens (407) and a filter (800) and be incident on the image sensor (700).

[0562] 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 positive (+) refractive power on the optical axis (OA). The first lens (401) may include a plastic material or a glass material, and may be, for example, a plastic material. At least one or both of the first surface (S1) and the second surface (S2) may be aspherical. The aspherical coefficients of the first and second surfaces (S1, S2) may be provided as S1 and S2 of L2 of FIG. 26.

[0563] 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 concave meniscus shape toward the sensor side. The first lens (401) may have a convex meniscus shape toward the object side. The first lens (401) may be made of a plastic material and may have an aspherical surface.

[0564] The refractive index (n1) of the first lens (401) can satisfy the condition of n1>1.5 or n1>1.52. When the refractive index (n1) of the first lens (401) satisfies the condition, the radius of curvature of the first and second lenses (401, 402) can be increased, and lens manufacturing can be facilitated. When the refractive index (n1) of the first lens (401) is smaller than the condition, the lens surfaces must be formed sharply concave or convex in order to increase the refractive power of the first and second lenses (401, 402), in which case lens manufacturing is not easy, the lens defect rate increases, and it may cause a decrease in yield. At least one or both of the first surface (S1) and the second surface (S2) of the first lens (401) can be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0565]

[0566] The second lens (402) may be arranged second from the object side. The second lens (402) may be arranged sixth 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 negative refractive power in 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.

[0567] The third surface (S3) on the object side of the second lens (402) may be convex with respect to the optical axis (OA), and the fourth surface (S4) on the sensor side may be concave. The second lens (402) may have a concave meniscus shape toward the sensor. The second lens (402) may have a convex meniscus shape 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. 26. At least one or both of the third surface (S3) and the fourth surface (S4) of the second lens (402) may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0568] 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 40 to 60 degrees.

[0569]

[0570] The third lens (403) may be arranged third from the object side. The third lens (403) may be arranged fifth 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 plastic material.

[0571] The object-side fifth surface (S5) of the third lens (403) with respect to the optical axis may be convex, and the sensor-side sixth surface (S6) may be convex. The seventh lens (407) may have a convex shape on both sides. The third lens (403) may be made of a plastic material and may be aspherical. At least one or both of the fifth surface (S5) and the sixth surface (S6) may be aspherical. The aspherical coefficients of the fifth and sixth surfaces (S5, S6) may be provided as S1 and S2 of L3 in FIG. 26.

[0572] The fifth surface (S5) of the third lens (403) may have a critical point from the optical axis (OA) to the end of the effective area. When the fifth surface (S5) has a critical point, it may be located in a range of 30% to 50%, preferably 35% to 40%, of the effective radius from the optical axis (OA). The critical point of the fifth surface (S5) may be located in a range of 0.3 mm to 1.5 mm, preferably 0.5 mm to 1 mm from the optical axis (OA).

[0573] The critical point of the fifth surface (S5) is a point where the sign of the slope value with respect to the optical axis (OA) and the direction perpendicular to the optical axis (OA) changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the slope value is 0. In addition, the critical point of the fifth surface (S5) may be a point where the slope value of the tangent line passing through the lens surface increases and then decreases, or a point where the slope value decreases and then increases. The sixth surface (S6) of the third lens (403) may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0574]

[0575] The fourth lens (404) may be arranged fourth from the object side. The fourth lens (404) may be arranged fourth 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. Unlike the refractive power of the fifth lens (405), 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 with a plastic material.

[0576] The seventh surface (S7) on the object side of the fourth lens (404) with respect to the optical axis may be convex, and the eighth surface (S8) on the sensor side may be concave. The fourth lens (404) may have a meniscus shape in which the sensor side is concave. The fourth lens (404) may have a meniscus shape in which the object side is convex. The fourth lens (404) is made of a plastic material and may have an aspherical surface. 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. 26. The seventh surface (S7) of the fourth lens (404) may have a critical point from the optical axis (OA) to the end of the effective area. When the seventh surface (S7) has a critical point, it may be located in a range of 25% to 45%, preferably in a range of 30% to 35%, of the effective radius from the optical axis (OA). The critical point of the seventh surface (S7) may be located in a range of 0.5 mm to 1.5 mm, preferably in a range of 0.5 mm to 1.0 mm from the optical axis (OA).

[0577] The critical point of the seventh surface (S7) is a point where the sign of the slope value with respect to the optical axis (OA) and the direction perpendicular to the optical axis (OA) changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the slope value is 0. In addition, the critical point of the seventh surface (S7) may be a point where the slope value of the tangent line passing through the lens surface increases and then decreases, or a point where the slope value decreases and then increases.

[0578] The eighth surface (S8) of the fourth lens (404) may have a critical point from the optical axis (OA) to the end of the effective area. When the eighth surface (S8) has a critical point, it may be located in a range of 35% to 55%, preferably in a range of 40% to 50%, of the effective radius from the optical axis (OA). The critical point of the eighth surface (S8) may be located in a range of 0.5 mm to 1.5 mm, preferably in a range of 1.0 mm to 1.4 mm from the optical axis (OA).

[0579] The critical point of the eighth surface (S8) is a point where the sign of the slope value with respect to the optical axis (OA) and the direction perpendicular to the optical axis (OA) changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the slope value is 0. In addition, the critical point of the eighth surface (S8) may be a point where the slope value of the tangent line passing through the lens surface increases and then decreases, or a point where the slope value decreases and then increases.

[0580]

[0581] The fifth lens (405) may be arranged as the fifth lens from the object side. The fifth lens (405) may be arranged as the third 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. Unlike the refractive power of the fourth lens (404), 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. The fifth lens (405) may be provided as the same material as the sixth lens (406).

[0582] 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 have an aspherical surface. At least one of the ninth surface (S9) and the tenth surface (S10) may be an aspherical surface. The aspherical coefficients of the ninth and tenth surfaces (S9, S10) may be provided as S1 and S2 of L5 in FIG. 26.

[0583] The ninth surface (S9) of the fifth lens (405) may have a critical point from the optical axis (OA) to the end of the effective area. When the ninth surface (S9) has a critical point, it may be located in a range of 40% to 60%, preferably 45% to 55%, of the effective radius from the optical axis (OA). The critical point of the ninth surface (S9) may be located in a range of 1.0 mm to 2.5 mm, preferably 1.3 mm to 1.8 mm from the optical axis (OA).

[0584] The critical point of the ninth surface (S9) is a point where the sign of the slope value with respect to the optical axis (OA) and the direction perpendicular to the optical axis (OA) changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the slope value is 0. In addition, the critical point of the ninth surface (S9) may be a point where the slope value of the tangent line passing through the lens surface increases and then decreases, or a point where the slope value decreases and then increases. The tenth surface (S10) of the fifth lens (405) may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0585]

[0586] The sixth lens (406) may be arranged as the sixth lens from the object side. The sixth lens (406) may be arranged as the second lens from the sensor side. The sixth lens (406) may be arranged between the fifth lens (405) and the seventh lens (407). The sixth lens (406) may have positive (+) or negative (-) refractive power on the optical axis (OA). The sixth lens (406) may have positive (+) refractive power. The sixth lens (406) may include a plastic or glass material. For example, the sixth lens (406) may be provided as a plastic material.

[0587] The object-side eleventh surface (S11) of the sixth lens (406) may be concave with respect to the optical axis, and the sensor-side twelfth surface (S12) may be convex. The sixth lens (406) may have a meniscus shape in which the sensor side is convex. The sixth lens (406) may have a meniscus shape in which the object side is concave. 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. 26. At least one or both of the eleventh surface (S11) and the twelfth surface (S12) of the sixth lens (406) may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0588]

[0589] The seventh lens (407) may be arranged closest to the sensor side. The seventh lens (407) may be arranged farthest from the object side. The seventh lens (407) may have positive (+) or negative (-) refractive power on the optical axis (OA). The seventh lens (407) may have negative (-) refractive power. The seventh lens (407) may include a plastic or glass material. For example, the seventh lens (407) may be made of a plastic material.

[0590] The object-side 13th surface (S13) of the seventh lens (407) on the optical axis may be concave, and the sensor-side 14th surface (S14) may be concave. The seventh lens (407) may have a concave shape on both sides. At least one of the 13th surface (S13) and the 14th surface (S14) may be aspherical. For example, both the 13th surface (S13) and the 14th surface (S14) may be aspherical. The aspherical coefficients of the 13th and 14th surfaces (S13, S14) may be provided as S1 and S2 of L8 in FIG. 26.

[0591] The 13th surface (S13) of the seventh lens (407) may be provided without a critical point from the optical axis (OA) to the end of the effective area. The 14th surface (S14) of the seventh lens (407) may have a critical point from the optical axis (OA) to the end of the effective area. When the 14th surface (S14) has a critical point, it may be located in a range of 35% to 55%, preferably in a range of 38% to 45%, of the effective radius from the optical axis (OA). The critical point of the 14th surface (S14) may be located in a range of 1.5 mm to 2.5 mm, preferably in a range of 1.8 mm to 2.4 mm from the optical axis (OA).

[0592] The critical point of the 14th surface (S14) is a point where the sign of the slope value with respect to the optical axis (OA) and the direction perpendicular to the optical axis (OA) changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the slope value is 0. In addition, the critical point of the 14th surface (S14) may be a point where the slope value of the tangent line passing through the lens surface increases and then decreases, or a point where the slope value decreases and then increases.

[0593]

[0594] LensSurfaceRadiusThicknessndvdSemiApertureFocal length1S13.6690.8381.546856.33152.0007.6600 S227.2260.050 1.920 2S323.3320.3001.679519.24591.909-38.3408 S412.2450.536 1.802 Stop-0.461 1.647 3 S539.6920.6721.546856.33151.80048.4339S6-79.3050.490 2.016 4S711.5930.5181.679519.24592.168-13.5336 S85.0360.346 2.637 5S910.4411.2621.546856.33153.2104.6543 S10-3.2210.050 3.615 6S11-12.3540.5921.679519.24593.865303.5734 S12-10.7131.113 4.230 7S13-3.1240.6001.546856.33154.464-3.9563 S147.5130.173 5.362 Cover glassS17-0.300 6.034 S18-0.700 6.120 Image 0.000

[0595]

[0596] Table 8 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 fourth embodiment of the present invention. At this time, the unit of the radius of curvature and thickness or distance may be mm.

[0597]

[0598] Item ValueItem ValueF6.78ET10.2994ΣIndex11.2257ET20.3603ΣAbbe283.0637ET30.3771ΣCT4.7819ET40.73 45ΣCG3.0452ET50.4005CA_max9.8260527ET60.4017CA_min3.711562ET71.4367CA_Aver5.8568 25F-number1.78CT_max1.262FOV_D82.63937CT_min0.3FOV_V55.82564CT_Aver0.683129FOV_H 70.38577EPD3.809ImgH6.45BFL1.172685SD6.304053TD7.827315TTL9LG1_F8.080LG2_F-25.029

[0599]

[0600] Table 9 shows the items of the mathematical formulas described above in the optical system (1300) of the embodiment, including the TTL (Total track length) (mm), BFL (Back focal length), effective focal length (F) (mm), ImgH (mm), effective diameter (CA) (mm), thickness (mm), TTL (mm), TD (mm), which is the optical axis distance from the first surface (S1) to the fourteenth surface (S14), SD (mm), which is the optical axis distance from the aperture (Stop) to the fourteenth surface (S14), sum of refractive indices, sum of Abbe numbers, sum of thicknesses (mm), sum of spacings between adjacent lenses, effective diameter characteristics, diagonal angle of view (FOV_D) (Degree), vertical angle of view (FOV_V) (Degree), horizontal angle of view (FOV_H) (Degree), edge thickness (ET), F number, composite focal length (LG1_F) of the first lens group (LG1), This is about the composite focal length (LG2_F) of the second lens group (LG2).

[0601]

[0602] The center thicknesses of the first to seventh lenses (401 to 407) are represented by CT1 to CT7, the edge thicknesses at the ends of the effective areas of each lens are represented by ET1 to ET7, the center gap between two adjacent lenses is represented by CG1 to CG6, and the edge gaps between the edges of each lens are represented by EG1 to EG7. 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 (401) to the upper surface of the image sensor (700).

[0603] As shown in Fig. 26, among the lenses of the lens unit in the fourth embodiment, the lens surfaces of the first to seventh lenses (401 to 407) may include aspherical surfaces having a 30th aspherical coefficient. For example, the first to seventh lenses (401 to 407) may include lens surfaces having a 30th aspherical coefficient. As described above, the aspherical surface having a 30th 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).

[0604] When comparing the absolute values ​​of the curvature radii of each lens, the curvature radii of the sixth surface (S6) of the third lens (403) on the optical axis (OA) may be the largest among the lenses, and the curvature radii of the thirteenth surface (S13) of the seventh lens (407) may be the smallest among the lenses. The difference between the maximum curvature radii and the minimum curvature radii may be 20 times or more, for example, in the range of 20 to 30 times. The curvature radii of the object-side surface of the seventh lens (407) may be the smallest among the lenses.

[0605] The absolute value of the curvature radius of the first surface (S1) of the first lens (401) may be smaller 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 larger 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 smaller 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 larger 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 larger 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). The absolute value of the radius of curvature of the thirteenth surface (S13) of the seventh lens (407) may be less than the absolute value of the radius of curvature of the fourteenth surface (S14).

[0606] The ratio of the radius of curvature of each lens can satisfy the following conditions.

[0607] Condition 1: 0.1 < |L1R1 / L1R2| < 0.5

[0608] Condition 2: 1.5 < |L2R1 / L2R2| < 2

[0609] Condition 3: 0.5 < |L3R1 / L3R2| < 1

[0610] Condition 4: 2 < |L4R1 / L4R2| < 2.5

[0611] Condition 5: 3 < |L5R1 / L5R2| < 3.5

[0612] Condition 6: 1 < |L6R1 / L6R2| < 1.5

[0613] Condition 7: 0.1 < |L7R1 / L7R2| < 0.5

[0614]

[0615] When describing the central thickness of the lenses based on the optical axis, the central thickness (CT5) of the fifth lens (405) is the largest among the lenses, and the central thickness (CT2) of the second lens (402) is the smallest among the lenses. The difference between the maximum and minimum central thicknesses among the lenses may be in the range of 0.5 mm or more and 1 mm or less.

[0616] By setting the central thickness (CT5) of the fifth lens (405) in the optical system (1300) to the largest, the light path incident on the image sensor (700) can be set, and good optical performance can be achieved at the set angle of view and focal length. By setting the central thickness (CT2) of the second lens (402) arranged closest to the aperture in the optical system (1300) to the smallest, space for the aperture arrangement can be secured, and operating interference of the aperture can be minimized.

[0617] The central thickness of each lens may satisfy any one of the following conditions:

[0618] Condition 1: CT5 > CT1 > CT2, CT3, CT4, CT6, CT7

[0619] Condition 2: CT1, CT3, CT4, CT5, CT6, CT7 > CT2

[0620] Condition 3: CT1, CT5 > CT3 > CT2, CT4, CT6, CT7

[0621] Condition 4: CT1, CT3, CT5, CT6, CT7 > CT4 > CT2

[0622] Condition 5: CT5 > CT1, CT2, CT3, CT4, CT6, CT7

[0623] Condition 6: CT1, CT3, CT5, CT7 > CT6 > CT2, CT4

[0624] Condition 7: CT1, CT3, CT5 > CT7 > CT2, CT4, CT6

[0625]

[0626] When describing the center spacing (CG) between the lenses, the center spacing (CG6) between the sixth lens (406) and the seventh lens (407) may be the maximum, and the center spacing (CG1) between the first and second lenses (401, 402) may be the minimum. The difference between the maximum center spacing and the minimum center spacing among the spaced lens spacings may be 1.0 mm or more, for example, in the range of 1.0 mm to 1.5 mm.

[0627] By setting the center distance (CG6) between the sixth lens (406) and the seventh lens (407) that are arranged closest to the image sensor (700) to the largest possible value, a gentle optical path can be formed in a short TTL, thereby forming a stable optical system. By setting the center distance (CG1) between the first lens (401) and the second lens (402) to the smallest possible value, space for diaphragm arrangement can be secured, and driving interference of the diaphragm can be minimized.

[0628] By setting the distance between the second lens (402) and the third lens (403) to be greater than the center thickness of the first lens (401), a space for arranging an aperture between the second lens (402) and the third lens (403) can be secured, and driving interference of the aperture can be minimized.

[0629] The center spacing between each lens can satisfy the conditions below.

[0630] Condition 1: CG2, CG3, CG4, CG5, CG6 > CG1

[0631] Condition 2: CG6 > CG2 > CG1, CG3, CG4, CG5

[0632] Condition 3: CG2, CG6 > CG3 > CG1, CG4, CG5

[0633] Condition 4: CG2, CG3, CG6 > CG4 > CG1, CG5

[0634] Condition 5: CG2, CG3, CG4, CG6 > CG5 > CG1

[0635] Condition 6: CG6 > CG1, CG2, CG3, CG4, CG5

[0636]

[0637] Regarding the effective diameter, the lens with the maximum effective diameter may be the seventh lens (407) closest to the image sensor (700). The lens with the maximum effective diameter may be a plastic lens. 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 with the maximum effective diameter may be the fourteenth surface (S14) of the seventh lens (407).

[0638] The lens having the minimum effective diameter may be any one of the plastic material lenses, and for example, the effective diameter of the second lens (402) may be the minimum within the lens unit. The lens surface having the minimum effective diameter may be the fifth surface (S5) of the third lens (403).

[0639] The effective diameter of each lens can satisfy any one of the conditions below.

[0640] Condition 1: CA_L4, CA_L5, CA_L6, CA_L7 > CA_L1 > CA_L2, CA_L3

[0641] Condition 2: CA_L1, CA_L3, CA_L4, CA_L5, CA_L6, CA_L7 > CA_L2

[0642] Condition 3: CA_L1, CA_L4, CA_L5, CA_L6, CA_L7 > CA_L3 > CA_L2

[0643] Condition 4: CA_L5, CA_L6, CA_L7 > CA_L4 > CA_L1, CA_L2, CA_L3

[0644] Condition 5: CA_L6, CA_L7 > CA_L5 > CA_L1, CA_L2, CA_L3, CA_L4

[0645] Condition 6: CA_L7 > CA_L6 > CA_L1, CA_L2, CA_L3, CA_L4, CA_L5

[0646] Condition 7: CA_L7 > CA_L1, CA_L2, CA_L3, CA_L4, CA_L5, CA_L6

[0647]

[0648] Regarding the refractive index, the refractive index of the second lens (402), the fourth lens (404), and the sixth lens (406) may be the highest among the lenses and may be greater than 1.5, for example, greater than 1.6. The first lens (401), the third lens (403), the fifth lens (405), and the seventh lens (407) may have the lowest refractive index among the lenses. For example, the refractive index of the first lens (401), the third lens (403), the fifth lens (405), and the seventh lens (407) may be the lowest among the lenses and may be less than 1.6, for example, less than 1.55. The difference between the maximum refractive index and the minimum refractive index may be 0.1 or more.

[0649] The refractive index of each lens can satisfy any of the conditions below.

[0650] Condition 1: n2, n4, n6 > n1 = n3 = n5 = n7

[0651] Condition 2: n1, n3, n5, n7 > n2 = n4 = n6

[0652]

[0653] Comparing the Abbe numbers, the Abbe numbers of the first lens (401), the third lens (403), the fifth lens (405), and the seventh lens (407) are the largest among the lenses and may be 50 or more. The Abbe numbers of the second lens (402), the fourth lens (404), and the sixth lens (406) are the smallest among the lenses and may be 30 or less. The difference between the maximum Abbe number and the minimum Abbe number may be 30 or more.

[0654] The Abbe number of each lens can satisfy any of the conditions below.

[0655] Condition 1: v1 = v3 = v5 = v7 > v2, v4, v6

[0656] Condition 2: v1, v3, v5, v7 > v2 = v4 = v6

[0657]

[0658] The focal lengths (F2, F4, F7) of the second, fourth, and seventh lenses (402, 404, and 407) may have negative (-) signs. The second, fourth, and seventh lenses (402, 404, and 407) may have negative (-) refractive power. The focal lengths (F1, F3, F5, and F6) of the first, third, fifth, and sixth lenses (401, 403, 405, and 406) may have positive (+) signs. The first, third, fifth, and sixth lenses (401, 403, 405, and 406) may have positive (+) refractive power. The seventh lens (407) having negative (-) refractive power may be arranged on the sensor side of the sixth lens (406) having positive (+) refractive power. Through this, light incident from the object side can move closer to the optical axis and then move away from the optical axis again, thereby forming a stable optical path.

[0659]

[0660] When comparing the focal lengths in absolute values, the focal length of the sixth lens (406) is the largest among the lenses, and may be 100 or more and 110 or less. Among the lenses, the sixth lens (406) made of plastic may have the largest focal length and the smallest refractive power. The focal length of the seventh lens (407) is the smallest among the lenses, and the absolute value of the focal length of the seventh lens (407) may be 2 or more and 10 or less. Among the lenses, the seventh lens (407) made of plastic may have the smallest focal length and the largest refractive power.

[0661] Among the lenses, the lens having the minimum focal length may be the seventh lens (407). The difference between the maximum focal length and the minimum focal length may be 70 or more or 90 or more. Accordingly, the optical system may have improved MTF characteristics, aberration control characteristics, resolution characteristics, etc. within the set angle of view range, and may have good optical performance in the periphery of the angle of view.

[0662] The absolute value of the focal length of each lens can satisfy any of the conditions below.

[0663] Condition 1: |f2|, |f3|, |f4|, |f6| > |f1| > |f5|, |f7|

[0664] Condition 2: |f3|, |f6| > |f2| > |f1|, |f4|, |f5|, |f7|

[0665] Condition 3: |f6| > |f3| > |f1|, |f2|, |f4|, |f5|, |f7|

[0666] Condition 4: |f2|, |f3|, |f6| > |f4| > |f1|, |f5|, |f7|

[0667] Condition 5: |f1|, |f2|, |f3|, |f4|, |f6| > |f5| > |f7|

[0668] Condition 6: |f6| > |f1|, |f2|, |f3|, |f4|, |f5|, |f7|

[0669] Condition 7: |f1|, |f2|, |f3|, |f4|, |f5|, |f6| > |f7|

[0670]

[0671] The thickness (T1) of the first lens (401) may be minimum at the edge and maximum at the center, and the maximum thickness is in the range of 2 to 3 times the minimum thickness. The thickness (T2) of the second lens (402) may be maximum at the edge and minimum at the center, and the maximum thickness is in the range of 1 to 1.5 times the minimum thickness. The thickness (T3) of the third lens (403) may be maximum at the center and minimum at the edge, and the maximum thickness is in the range of 1.5 to 2 times the minimum thickness. The thickness (T4) of the fourth lens (404) may be minimum at the center and maximum at the edge, and the maximum thickness is in the range of 1 to 1.5 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 3 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 1.5 times the minimum thickness. The thickness (T7) of the seventh lens (407) 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.

[0672] The thickness of each lens can satisfy any of the conditions below.

[0673] Condition 1: 2.5 < CT1 / ET1 < 3, 0.1 < ET1 / CT1 < 0.5

[0674] Condition 2: 0.5 < CT2 / ET2 < 1, 1 < ET2 / CT2 < 1.5

[0675] Condition 3: 1.5 < CT3 / ET3 < 2, 0.5 < ET3 / CT3 < 1

[0676] Condition 4: 0.5 < CT4 / ET4 < 1, 1 < ET4 / CT4 < 1.5

[0677] Condition 5: 3.0 < CT5 / ET5 < 3.5, 0.1 < ET5 / CT5 < 0.5

[0678] Condition 6: 1 < CT6 / ET6 < 1.5, 0.5 < ET6 / CT6 < 1

[0679] Condition 7: 0.1 < CT7 / ET7 < 0.5, 2 < ET7 / CT7 < 2.5

[0680] Condition 9: 1 < ΣCT / ΣET < 1.5, 0.5 < ΣET / ΣCT < 1

[0681]

[0682] Among the gaps (G1-G6) 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 edge and a maximum in the center. 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 edge and a minimum in the center. 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. The sixth gap (G6) between the sixth and seventh lenses (406, 407) may have a maximum in the center and a minimum in the edge.

[0683]

[0684] An optical system according to a fifth embodiment of the invention will be described.

[0685] Referring to FIGS. 33 and 34, the optical system (1400) includes a lens unit, and the lens unit may include a first lens (501) to a seventh lens (507). The first to seventh lenses (501 to 507) may be sequentially arranged along the optical axis (OA) of the optical system (1400). Light corresponding to information about an object may pass through the first lens (501) to the seventh lens (507) and the filter (800) and be incident on the image sensor (700).

[0686] 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 positive (+) refractive power on the optical axis (OA). The first lens (501) may include a plastic material or a glass material, and may be, for example, a plastic material. At least one or both of the first surface (S1) and the second surface (S2) may be aspherical. The aspherical coefficients of the first and second surfaces (S1, S2) may be provided as S1 and S2 of L1 in FIG. 35.

[0687] 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 concave meniscus shape toward the sensor side. The first lens (501) may have a convex meniscus shape toward the object side. The first lens (501) may be made of a plastic material and may have an aspherical surface. The first surface (S1) of the first lens (501) may be provided without a critical point from the optical axis to the end of the effective area.

[0688] The second surface (S2) of the first lens (501) may have a critical point from the optical axis to the end of the effective area. When the second surface (S2) has a critical point, it may be located in a range of 25% to 45%, preferably 30% to 40%, of the effective radius from the optical axis. The critical point of the second surface (S2) may be located in a range of 0.2 mm to 1.5 mm, preferably 0.5 mm to 1 mm from the optical axis. The critical point of the second surface (S2) may be a point where the sign of the gradient value with respect to the optical axis and the direction perpendicular to the optical axis changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the gradient value is 0. In addition, the critical point of the second surface (S2) may be a point where the gradient value of a tangent passing through the lens surface increases and then decreases, or a point where the gradient value decreases and then increases.

[0689]

[0690] The second lens (502) may be arranged second from the object side. The second lens (502) may be arranged sixth 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 on 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.

[0691] The third surface (S3) on the object side of the second lens (502) with respect to the optical axis (OA) may be convex, and the fourth surface (S4) on the sensor side may be concave. The second lens (502) may have a concave meniscus shape toward the sensor side. The second lens (502) may have a convex meniscus shape toward the object side. The second lens (502) 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. 35.

[0692] The third surface (S3) of the second lens (502) may have a critical point from the optical axis to the end of the effective area. When the third surface (S3) has a critical point, it may be located in a range of 20% to 40%, preferably in a range of 25% to 35%, of the effective radius from the optical axis. The critical point of the third surface (S3) may be located in a range of 0.2 mm to 1.5 mm, preferably in a range of 0.5 mm to 1 mm from the optical axis. The critical point of the third surface (S3) may be a point where the sign of the gradient value with respect to the optical axis and the direction perpendicular to the optical axis changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the gradient value is 0. In addition, the critical point of the third surface (S3) may be a point where the gradient value of a tangent passing through the lens surface increases and then decreases, or a point where the gradient value decreases and then increases. The fourth surface (S4) of the second lens (502) can be provided without a critical point from the optical axis to the end of the effective area.

[0693] The aperture (Stop) may be arranged around the sensor-side fourth surface (S4) of the second lens (502). The aperture (Stop) may be arranged around the object-side fifth surface (S5) of the third lens (503). The aperture may move in the direction of the optical axis. The aperture may reduce the TTL within the field of view range, and may enable miniaturization of the optical system. Accordingly, a decrease in the yield by weight of the optical system may be prevented, and production efficiency may be improved.

[0694] The shapes of the lens surfaces facing the aperture can be formed similarly. The sign of the radius of curvature of the object-side surface of the second lens (502) in the object-side direction of the aperture and the sign of the radius of curvature of the sensor-side surface of the third lens (503) in the sensor-side direction of the aperture can be the same. This makes it possible to secure space between the lenses for arranging the aperture and the aperture drive device, and minimize interference with the aperture drive.

[0695]

[0696] The third lens (503) may be arranged third from the object side. The third lens (503) may be arranged fifth 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 plastic material.

[0697] 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 meniscus shape in which the sensor side is concave. The third lens (503) may have a meniscus shape in which the object side is convex. The third lens (503) may be made of a plastic material and may be aspherical. At least one or both of the fifth surface (S5) and the sixth surface (S6) may be aspherical. The aspherical coefficients of the fifth and sixth surfaces (S5, S6) may be provided as S1 and S2 of L3 in FIG. 35.

[0698] The fifth surface (S5) of the third lens (503) may have a critical point from the optical axis to the end of the effective area. When the fifth surface (S5) has a critical point, it may be located in a range of 60% to 80%, preferably in a range of 65% to 75%, of the effective radius from the optical axis. The critical point of the fifth surface (S5) may be located in a range of 0.5 mm to 2.0 mm, preferably in a range of 1 mm to 1.5 mm from the optical axis. The critical point of the fifth surface (S5) may be a point where the sign of the gradient value with respect to the optical axis and the direction perpendicular to the optical axis changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the gradient value is 0. In addition, the critical point of the fifth surface (S5) may be a point where the gradient value of a tangent passing through the lens surface increases and then decreases, or a point where the gradient value decreases and then increases.

[0699] The sixth surface (S6) of the third lens (503) may have a critical point from the optical axis to the end of the effective area. When the sixth surface (S6) has a critical point, it may be located in a range of 40% to 60%, preferably 50% to 55%, of the effective radius from the optical axis. The critical point of the sixth surface (S6) may be located in a range of 0.5 mm to 2 mm, preferably 1 mm to 1.5 mm, from the optical axis. The critical point of the sixth surface (S6) may be a point where the sign of the gradient value with respect to the optical axis and the direction perpendicular to the optical axis changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the gradient value is 0. In addition, the critical point of the sixth surface (S6) may be a point where the gradient value of a tangent passing through the lens surface increases and then decreases, or a point where the gradient value decreases and then increases.

[0700]

[0701] The fourth lens (504) may be arranged fourth from the object side. The fourth lens (504) may be arranged fourth 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 negative (-) 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.

[0702] The seventh surface (S7) on the object side of the fourth lens (504) with respect to the optical axis may be convex, and the eighth surface (S8) on the sensor side may be concave. The fourth lens (504) may have a concave meniscus shape on the sensor side. The fourth lens (504) may have a convex meniscus shape on the object side. The fourth lens (504) is made of a plastic material and may have an aspherical surface. 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. 35.

[0703] The seventh surface (S7) of the fourth lens (504) may have a critical point from the optical axis to the end of the effective area. When the seventh surface (S7) has a critical point, it may be located in a range of 35% to 55%, preferably 40% to 50%, of the effective radius from the optical axis. The critical point of the seventh surface (S7) may be located in a range of 0.3 mm to 1.5 mm, preferably 0.5 mm to 1.2 mm from the optical axis. The critical point of the seventh surface (S7) may be a point where the sign of the gradient value with respect to the optical axis and the direction perpendicular to the optical axis changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the gradient value is 0. In addition, the critical point of the seventh surface (S7) may be a point where the gradient value of a tangent passing through the lens surface increases and then decreases, or a point where the gradient value decreases and then increases.

[0704] The eighth surface (S8) of the fourth lens (504) may have a critical point from the optical axis to the end of the effective area. When the eighth surface (S8) has a critical point, it may be located in a range of 50% to 70%, preferably 55% to 65%, of the effective radius from the optical axis. The critical point of the eighth surface (S8) may be located in a range of 0.5 mm to 2 mm, preferably 1 mm to 1.8 mm from the optical axis. The critical point of the eighth surface (S8) may be a point where the sign of the gradient value with respect to the optical axis and the direction perpendicular to the optical axis changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the gradient value is 0. In addition, the critical point of the eighth surface (S8) may be a point where the gradient value of a tangent passing through the lens surface increases and then decreases, or a point where the gradient value decreases and then increases.

[0705]

[0706] The fifth lens (505) may be arranged as the fifth lens from the object side. The fifth lens (505) may be arranged as the third 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 positive (+) 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.

[0707] 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 convex. The fifth lens (505) may have a meniscus shape in which the sensor side is convex. The fifth lens (505) may have a meniscus shape in which the object side is concave. The fifth lens (505) may be made of a plastic material and may have an aspherical surface. At least one of the ninth surface (S9) and the tenth surface (S10) may be an aspherical surface. The aspherical coefficients of the ninth and tenth surfaces (S9, S10) may be provided as S1 and S2 of L5 in FIG. 35.

[0708] The ninth surface (S9) of the fifth lens (505) may have a critical point from the optical axis to the end of the effective area. When the ninth surface (S9) has a critical point, it may be located in a range of 60% to 80%, preferably 65% ​​to 75%, of the effective radius from the optical axis. The critical point of the ninth surface (S9) may be located in a range of 1 mm to 2.5 mm, preferably 1.5 mm to 2 mm, from the optical axis. The critical point of the ninth surface (S9) may be a point where the sign of the gradient value with respect to the optical axis and the direction perpendicular to the optical axis changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the gradient value is 0. In addition, the critical point of the ninth surface (S9) may be a point where the gradient value of a tangent passing through the lens surface increases and then decreases, or a point where the gradient value decreases and then increases. The tenth surface (S10) of the fifth lens (505) can be provided without a critical point from the optical axis to the end of the effective area.

[0709]

[0710] The sixth lens (506) may be arranged as the sixth lens from the object side. The sixth lens (506) may be arranged as the second lens from the sensor side. The sixth lens (506) may be arranged between the fifth lens (505) and the seventh lens (507). The sixth lens (506) may have positive (+) or negative (-) refractive power on the optical axis (OA). The sixth lens (506) may have negative (-) refractive power. The sixth lens (506) may include a plastic or glass material. For example, the sixth lens (506) may be provided as a plastic material.

[0711] The object-side eleventh surface (S11) of the sixth lens (506) with respect to the optical axis may be convex, and the sensor-side twelfth surface (S12) may be concave. The sixth lens (506) may have a concave meniscus shape on the sensor side. The sixth lens (506) may have a convex meniscus shape on the object side. 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. 35.

[0712] The eleventh surface (S11) of the sixth lens (506) may have a critical point from the optical axis (OA) to the end of the effective area. When the eleventh surface (S11) has a critical point, it may be located in a range of 50% to 70%, preferably in a range of 55% to 65%, of the effective radius from the optical axis (OA). The critical point of the eleventh surface (S11) may be located in a range of 1 mm to 2.5 mm, preferably in a range of 1.5 mm to 2 mm from the optical axis (OA).

[0713] The critical point of the eleventh surface (S11) is a point where the sign of the slope value with respect to the optical axis (OA) and the direction perpendicular to the optical axis (OA) changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the slope value is 0. In addition, the critical point of the eleventh surface (S11) may be a point where the slope value of the tangent line passing through the lens surface increases and then decreases, or a point where the slope value decreases and then increases.

[0714] The twelfth surface (S12) of the sixth lens (506) may have 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 40% to 60%, preferably 45% to 55%, of the effective radius from the optical axis (OA). The critical point of the twelfth surface (S12) may be located in a range of 1 mm to 2.5 mm, preferably 1.5 mm to 2 mm, from the optical axis (OA).

[0715] The critical point of the 12th surface (S12) is a point where the sign of the slope value with respect to the optical axis (OA) and the direction perpendicular to the optical axis (OA) changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the slope value is 0. In addition, the critical point of the 12th surface (S12) may be a point where the slope value of the tangent line passing through the lens surface increases and then decreases, or a point where the slope value decreases and then increases.

[0716]

[0717] The seventh lens (507) may be arranged closest to the sensor side. The seventh lens (507) may be arranged farthest from the object side. The seventh lens (507) may have positive (+) or negative (-) refractive power on the optical axis (OA). The seventh lens (507) may have negative (-) refractive power. The seventh lens (507) may include a plastic or glass material. For example, the seventh lens (507) may be made of a plastic material.

[0718] The object-side 13th surface (S13) of the seventh lens (507) on the optical axis may be concave, and the sensor-side 14th surface (S14) may be concave. The seventh lens (507) may have a concave shape on both sides. At least one of the 13th surface (S13) and the 14th surface (S14) may be aspherical. For example, both the 13th surface (S13) and the 14th surface (S14) may be aspherical. The aspherical coefficients of the 13th and 14th surfaces (S13, S14) may be provided as S1 and S2 of L8 in FIG. 35.

[0719] The 13th surface (S13) of the seventh lens (507) may be provided without a critical point from the optical axis (OA) to the end of the effective area. The 14th surface (S14) of the seventh lens (507) may have a critical point from the optical axis (OA) to the end of the effective area. When the 14th surface (S14) has a critical point, it may be located in a range of 40% to 60%, preferably in a range of 45% to 55%, of the effective radius from the optical axis (OA). The critical point of the 14th surface (S14) may be located in a range of 1.5 mm to 2.5 mm, preferably in a range of 1.8 mm to 2.3 mm from the optical axis (OA).

[0720] The critical point of the 14th surface (S14) is a point where the sign of the slope value with respect to the optical axis (OA) and the direction perpendicular to the optical axis (OA) changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the slope value is 0. In addition, the critical point of the 14th surface (S14) may be a point where the slope value of the tangent line passing through the lens surface increases and then decreases, or a point where the slope value decreases and then increases.

[0721]

[0722] LensSurfaceRadiusThicknessndvdSemiApertureFocal length1S13.69310.94501.545956.09482.20007.3842 S240.05560.1000 2.1750 2S340.07440.30001.677619.24592.0563-47.9330 S417.8851Variable(D1) 1.8867 Stop-Variable(D2) 1.3000 3S514.75550.62091.545956.09482.0416182.3510 S617.06580.2974 2.1378 4S76.34520.40001.677619.24592.1785-13.5959 S83.66160.2127 2.5054 5S9-108.45340.84781.545956.09482.57375.9408 S10-3.15780.1000 2.8086 6S116.92720.78421.677619.24593.0943-208.7277 S126.30180.9986 3.4577 7S13-149.28270.60001.545956.09483.8416-6.0826 S143.40100.2792 4.6130 FilterS15 0.2400 4.7484 S16 0.4400 4.7931 Image 0.0000 4.9210

[0723]

[0724] Table 11 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 fifth embodiment of the present invention. At this time, the unit of the radius of curvature and thickness or distance may be mm.

[0725]

[0726] Mode 1 Mode 2 D10.25001.5300 D21.33910.0591

[0727]

[0728] Table 12 shows the distances (D1, D2) between the lenses and the aperture that are variable when the optical system according to the fifth embodiment of the present invention operates in either the first mode or the second mode. The aperture can be moved in the direction of the optical axis by the aperture device. As the aperture moves, the distance between adjacent lenses and the aperture can change. The aperture can be a moving group, and the lens unit can be a fixed group. The aperture can be arranged between the first lens group (LG1) and the second lens group (LG2). The aperture can be arranged between the second lens (502) and the third lens (503).

[0729] Here, the first mode means a state in which the aperture is placed adjacent to the lens placed on the object side among two adjacent lenses, and the second mode means a state in which the aperture is placed adjacent to the lens placed on the sensor side among two adjacent lenses.

[0730] When operating from the first mode to the second mode, the distance (D1) between the lens closest to the sensor side in the first lens group (LG1) and the aperture may increase, and the distance (D2) between the lens closest to the object side in the second lens group (LG2) and the aperture may decrease. When operating from the first mode to the second mode, the distance (D1) between the second lens (502) and the aperture may increase, and the distance (D2) between the third lens (503) and the aperture may decrease.

[0731] When operating from the second mode to the first mode, the distance (D1) between the lens closest to the sensor side in the first lens group (LG1) and the aperture may become smaller, and the distance (D2) between the lens closest to the object side in the second lens group (LG2) and the aperture may become larger. When operating from the second mode to the first mode, the distance (D1) between the second lens (502) and the aperture may become smaller, and the distance (D2) between the third lens (503) and the aperture may become larger.

[0732] The stroke length of the aperture may be shorter than the gap between the first lens group (LG1) and the second lens group (LG2). The stroke length of the aperture may be shorter than the gap between the second lens (502) and the third lens (503). The stroke length of the aperture may be in the range of 1 mm to 2 mm, and preferably in the range of 1.2 mm to 1.5 mm.

[0733] As the position of the aperture moves in the direction of the optical axis, the F-number, EPD, and SD of the optical system may change. The F-number may mean a value obtained by dividing the total focal length (F) by the diameter through which light passes (EPD). The EPD means the diameter through which light enters the optical system and may mean the entrance pupil. The SD may mean the distance from the aperture to the sensor side of the seventh lens (507) on the optical axis. In the first mode, the F-number may be maximum, and in the second mode, the F-number may be minimum. In the first mode, the EPD may be minimum, and in the second mode, the EPD may be maximum. In the first mode, the SD may be maximum, and in the second mode, the SD may be minimum.

[0734]

[0735] Item ValueItem ValueF6.6500ET10.3195ΣIndex11.2164ET20.3608ΣAbbe282.1169ET30.3810ΣCT4.4979ET40.6489ΣCG3.29 78ET50.3430CA_max8.4546ET60.4281CA_min3.9430ET71.7289CA_Aver5.3672F-number_12.2139CT_max0.9 450F-number_21.8295CT_min0.3000FOV_D70.4736CT_Aver0.6426FOV_H58.5549EPD_13.0037FOV_V46.0325 EPD_23.6350F_LG18.5000BFL0.9592F_LG2-45.6069TD7.7956SD_16.2006ImgH4.9200SD_24.9606TTL8.7549

[0736]

[0737] Table 13 shows the items of the mathematical formulas described above in the optical system (1400) of the embodiment, including the TTL (Total track length) (mm), BFL (Back focal length), effective focal length (F) (mm), ImgH (mm), effective diameter (CA) (mm), thickness (mm), TTL (mm), TD (mm), which is the optical axis distance from the first surface (S1) to the fourteenth surface (S14), SD_1 (mm), which is the optical axis distance from the stop (Stop) to the fourteenth surface (S14) in the first mode, SD_2 (mm), which is the optical axis distance from the stop (Stop) to the fourteenth surface (S14) in the second mode, EPD_1, which is the entrance pupil in the first mode, EPD_2, which is the entrance pupil in the second mode, F-number_1, which is the F-number in the first mode, F-number_2, which is the F-number in the second mode, sum of refractive indices, sum of Abbe numbers, sum of thickness (mm), It is about the sum of the gaps between adjacent lenses, the effective aperture characteristics, the diagonal field of view (FOV_D)(Degree), the vertical field of view (FOV_V)(Degree), the horizontal field of view (FOV_H)(Degree), the edge thickness (ET), etc. F_LG1 is the composite focal length of the first lens group (LG1)(mm), and F_LG2 is the composite focal length of the second lens group (LG2)(mm).

[0738]

[0739] The center thicknesses of the first to seventh lenses (501 to 507) are represented by CT1 to CT7, the edge thicknesses at the ends of the effective areas of each lens are represented by ET1 to ET7, the center gap between two adjacent lenses is represented by CG1 to CG6, and the edge gaps between the edges of each lens are represented by EG1 to EG7. 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 (501) to the upper surface of the image sensor (700).

[0740] As shown in Fig. 35, among the lenses of the lens unit in the fifth embodiment, the lens surfaces of the first to seventh lenses (501 to 507) may include aspherical surfaces having a 30th-order aspherical surface coefficient. For example, the first to seventh lenses (501 to 507) 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, thereby effectively compensating for the optical performance of the periphery of the field of view (FOV).

[0741] When comparing the absolute values ​​of the curvature radii of each lens, the curvature radii of the thirteenth surface (S13) of the seventh lens (507) 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 (505) may be the smallest among the lenses. The difference between the maximum curvature radii and the minimum curvature radii may be 30 times or more, for example, in the range of 30 to 50 times. The curvature radii of the sensor-side surface of the fifth lens (505) may be the smallest among the lenses.

[0742] The absolute value of the curvature radius of the first surface (S1) of the first lens (501) may be smaller 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 larger 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 smaller 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 larger 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 larger 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 greater than the absolute value of the radius of curvature of the twelfth surface (S12). The absolute value of the radius of curvature of the thirteenth surface (S13) of the seventh lens (507) may be greater than the absolute value of the radius of curvature of the fourteenth surface (S14).

[0743] The ratio of the radius of curvature of each lens can satisfy the following conditions.

[0744] Condition 1: 0.05 < |L1R1 / L1R2| < 0.1

[0745] Condition 2: 2 < |L2R1 / L2R2| < 2.5

[0746] Condition 3: 0.5 < |L3R1 / L3R2| < 1

[0747] Condition 4: 1.5 < |L4R1 / L4R2| < 2

[0748] Condition 5: 30 < |L5R1 / L5R2| < 50

[0749] Condition 6: 1 < |L6R1 / L6R2| < 1.5

[0750] Condition 7: 30 < |L7R1 / L7R2| < 50

[0751]

[0752] When describing the central thickness of the lenses based on the optical axis, the central thickness (CT1) of the first lens (501) is the largest among the lenses, and the central thickness (CT2) of the second lens (502) is the smallest among the lenses. The difference between the maximum and minimum central thicknesses among the lenses may be in the range of 0.5 mm or more and 1 mm or less.

[0753] The central thickness of each lens may satisfy any one of the following conditions:

[0754] Condition 1: CT1 > CT2, CT3, CT4, CT5, CT6, CT7

[0755] Condition 2: CT1, CT3, CT4, CT5, CT6, CT7 > CT2

[0756] Condition 3: CT1, CT5, CT6 > CT3 > CT2, CT4, CT7

[0757] Condition 4: CT1, CT3, CT5, CT6, CT7 > CT4 > CT2

[0758] Condition 5: CT1 > CT5 > CT2, CT3, CT4, CT6, CT7

[0759] Condition 6: CT1, CT5 > CT6 > CT2, CT3, CT4, CT7

[0760] Condition 7: CT1, CT3, CT5, CT6 > CT7 > CT2, CT4

[0761]

[0762] When describing the center spacing (CG) between the lenses, the center spacing (CG2) between the second lens (502) and the third lens (503) may be maximum, and the center spacing (CG1) between the first and second lenses (501, 502) and the center spacing (CG5) between the fifth and sixth lenses (505, 506) may be minimum. The difference between the maximum center spacing and the minimum center spacing among the spaced lens spacings may be 1 mm or more, for example, in the range of 1 mm to 1.5 mm.

[0763] The center spacing between each lens can satisfy the conditions below.

[0764] Condition 1: CG2, CG3, CG4, CG6 > CG1 = CG5

[0765] Condition 2: CG2 > CG1, CG3, CG4, CG5, CG6

[0766] Condition 3: CG2, CG6 > CG3 > CG1, CG4, CG5

[0767] Condition 4: CG2, CG3, CG6 > CG4 > CG1, CG5

[0768] Condition 5: CG2 > CG6 > CG1, CG3, CG4, CG5

[0769]

[0770] Regarding the effective diameter, the lens with the maximum effective diameter may be the seventh lens (507) closest to the image sensor (700). The lens with the maximum effective diameter may be a plastic lens. 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 with the maximum effective diameter may be the fourteenth surface (S14) of the seventh lens (507).

[0771] The lens having the minimum effective diameter may be any one of the plastic material lenses, and for example, the effective diameter of the second lens (502) may be the minimum within the lens unit. The lens surface having the minimum effective diameter may be the fourth surface (S4) of the second lens (502).

[0772] The effective diameter of each lens can satisfy any one of the conditions below.

[0773] Condition 1: CA_L4, CA_L5, CA_L6, CA_L7 > CA_L1 > CA_L2, CA_L3

[0774] Condition 2: CA_L1, CA_L3, CA_L4, CA_L5, CA_L6, CA_L7 > CA_L2

[0775] Condition 3: CA_L1, CA_L4, CA_L5, CA_L6, CA_L7 > CA_L3 > CA_L2

[0776] Condition 4: CA_L5, CA_L6, CA_L7 > CA_L4 > CA_L1, CA_L2, CA_L3

[0777] Condition 5: CA_L6, CA_L7 > CA_L5 > CA_L1, CA_L2, CA_L3, CA_L4

[0778] Condition 6: CA_L7 > CA_L6 > CA_L1, CA_L2, CA_L3, CA_L4, CA_L5

[0779] Condition 7: CA_L7 > CA_L1, CA_L2, CA_L3, CA_L4, CA_L5, CA_L6

[0780]

[0781] Regarding the refractive index, the refractive index of the second lens (502), the fourth lens (504), and the sixth lens (506) may be the highest among the lenses and may be greater than 1.5, for example, greater than 1.6. The first lens (501), the third lens (503), the fifth lens (505), and the seventh lens (507) may have the lowest refractive index among the lenses. For example, the refractive index of the first lens (501), the third lens (503), the fifth lens (505), and the seventh lens (507) may be the lowest among the lenses and may be less than 1.6, for example, less than 1.55. The difference between the maximum refractive index and the minimum refractive index may be 0.1 or more.

[0782] The refractive index of each lens can satisfy any of the conditions below.

[0783] Condition 1: n2, n4, n6 > n1 = n3 = n5 = n7

[0784] Condition 2: n2 = n4 = n6 > n1, n3, n5, n7

[0785]

[0786] Comparing the Abbe numbers, the Abbe numbers of the first lens (501), the third lens (503), the fifth lens (505), and the seventh lens (507) are the largest among the lenses and may be 50 or more. The Abbe numbers of the second lens (502), the fourth lens (504), and the sixth lens (506) are the smallest among the lenses and may be 20 or less. The difference between the maximum Abbe number and the minimum Abbe number may be 30 or more.

[0787] The Abbe number of each lens can satisfy any of the conditions below.

[0788] Condition 1: v1 = v3 = v5 = v7 > v2, v4, v6

[0789] Condition 2: v1, v3, v5, v7 > v2 = v4 = v6

[0790]

[0791] The focal lengths (F2, F4, F6, F7) of the second, fourth, sixth, and seventh lenses (502, 504, 506, and 507) may have negative (-) signs. The second, fourth, sixth, and seventh lenses (502, 504, 506, and 507) may have negative (-) refractive power. The focal lengths (F1, F3, and F5) of the first, third, and fifth lenses (501, 503, and 505) may have positive (+) signs. The first, third, and fifth lenses (501, 503, and 505) may have positive (+) refractive power. The sixth and seventh lenses (506, 507) having negative (-) refractive power may be arranged on the sensor side of the fifth lens (505) having positive (+) refractive power. Through this, light incident from the object side can move closer to the optical axis and then move away from the optical axis again, thereby forming a stable optical path.

[0792]

[0793] 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 200 or more and 250 or less. Among the lenses, the sixth lens (506) made of plastic may have the largest focal length and the smallest refractive power. 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 5 or more and 10 or less. Among the lenses, the fifth lens (505) made of plastic may have the smallest focal length and the largest refractive power.

[0794] Among the lenses, the lens having the minimum focal length may be the fifth lens (505). The difference between the maximum focal length and the minimum focal length may be 200 or more or 250 or more. Accordingly, the optical system may have improved MTF characteristics, aberration control characteristics, resolution characteristics, etc. within the set angle of view range, and may have good optical performance in the periphery of the angle of view.

[0795] The absolute value of the focal length of each lens can satisfy any of the conditions below.

[0796] Condition 1: |f2|, |f3|, |f4|, |f6| > |f1| > |f5|, |f7|

[0797] Condition 2: |f3|, |f6| > |f2| > |f1|, |f4|, |f5|, |f7|

[0798] Condition 3: |f6| > |f3| > |f1|, |f2|, |f4|, |f5|, |f7|

[0799] Condition 4: |f2|, |f3|, |f6| > |f4| > |f1|, |f5|, |f7|

[0800] Condition 5: |f1|, |f2|, |f3|, |f4|, |f6|, |f7| > |f5|

[0801] Condition 6: |f6| > |f1|, |f2|, |f3|, |f4|, |f5|, |f7|

[0802] Condition 7: |f1|, |f2|, |f3|, |f4|, |f6| > |f7| > |f5|

[0803]

[0804] The thickness (T1) of the first lens (501) may be minimum at the edge and maximum at the center, and the maximum thickness is in the range of 2.5 to 3 times the minimum thickness. The thickness (T2) of the second lens (502) may be maximum at the edge and minimum at the center, and the maximum thickness is in the range of 1 to 1.5 times the minimum thickness. The thickness (T3) of the third lens (503) may be maximum at the center and minimum at the edge, and the maximum thickness is in the range of 1.5 to 2 times the minimum thickness. The thickness (T4) of the fourth lens (504) may be minimum at the center and maximum at the edge, and the maximum thickness is in the range of 1.5 to 2 times the minimum thickness. The thickness (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 2 to 2.5 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. The thickness (T7) of the seventh lens (507) may be minimum at the center and maximum at the edge, and the maximum thickness is in the range of 2.5 to 3 times the minimum thickness.

[0805] The thickness of each lens can satisfy any of the conditions below.

[0806] Condition 1: 2.5 < CT1 / ET1 < 3, 0.1 < ET1 / CT1 < 0.5

[0807] Condition 2: 0.5 < CT2 / ET2 < 1, 1 < ET2 / CT2 < 1.5

[0808] Condition 3: 1.5 < CT3 / ET3 < 2, 0.5 < ET3 / CT3 < 1

[0809] Condition 4: 0.5 < CT4 / ET4 < 1, 1.5 < ET4 / CT4 < 2

[0810] Condition 5: 2 < CT5 / ET5 < 2.5, 0.1 < ET5 / CT5 < 0.5

[0811] Condition 6: 1.5 < CT6 / ET6 < 2, 0.5 < ET6 / CT6 < 1

[0812] Condition 7: 0.1 < CT7 / ET7 < 0.5, 2.5 < ET7 / CT7 < 3

[0813] Condition 8: 1 < ΣCT / ΣET < 1.5, 0.5 < ΣET / ΣCT < 1

[0814]

[0815] Among the gaps (G1-G6) between the lenses, the first gap (G1) between the first and second lenses (501, 502) may have a minimum in the center and a maximum in the edge. The second gap (G2) between the second and third lenses (502, 503) may have a minimum in the edge and a maximum in the center. The third gap (G3) between the third and fourth lenses (503, 504) may have a minimum in the edge and a maximum in the center. The fourth gap (G4) between the fourth and fifth lenses (504, 505) may have a minimum in the edge and a maximum 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. The sixth gap (G6) between the sixth and seventh lenses (506, 507) may have a maximum in the center and a minimum in the edge.

[0816]

[0817] An optical system according to the sixth embodiment of the invention will be described.

[0818] Referring to FIGS. 43 and 44, the optical system (1500) includes a lens unit, and the lens unit may include a first lens (601) to a seventh lens (607). The first to seventh lenses (601 to 607) may be sequentially arranged along the optical axis (OA) of the optical system (1500). Light corresponding to information about an object may pass through the first lens (601) to the seventh lens (607) and a filter (800) and be incident on the image sensor (700).

[0819] 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 positive (+) refractive power on the optical axis (OA). The first lens (601) may include a plastic material or a glass material, and may be, for example, a plastic material. At least one or both of the first surface (S1) and the second surface (S2) may be aspherical. The aspherical coefficients of the first and second surfaces (S1, S2) may be provided as S1 and S2 of L2 in FIG. 45.

[0820] 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 concave meniscus shape toward the sensor side. The first lens (601) may have a convex meniscus shape toward the object side. The first lens (601) may be made of a plastic material and may have an aspherical surface. The first surface (S1) of the first lens (601) may be provided without a critical point from the optical axis to the end of the effective area.

[0821] The second surface (S2) of the first lens (601) may have a critical point from the optical axis to the end of the effective area. When the second surface (S2) has a critical point, it may be located in a range of 55% to 75%, preferably 60% to 70%, of the effective radius from the optical axis. The critical point of the second surface (S2) may be located in a range of 0.5 mm to 2 mm, preferably 1 mm to 1.5 mm from the optical axis. The critical point of the second surface (S2) may be a point where the sign of the gradient value with respect to the optical axis and the direction perpendicular to the optical axis changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the gradient value is 0. In addition, the critical point of the second surface (S2) may be a point where the gradient value of a tangent passing through the lens surface increases and then decreases, or a point where the gradient value decreases and then increases.

[0822]

[0823] The second lens (602) may be arranged second from the object side. The second lens (602) may be arranged sixth 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.

[0824] The third surface (S3) on the object side of the second lens (602) with respect to the optical axis (OA) may be convex, and the fourth surface (S4) on the sensor side may be concave. The second lens (602) may have a concave meniscus shape toward the sensor side. The second lens (602) may have a convex meniscus shape toward the object side. The second lens (602) 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. 45.

[0825] The third surface (S3) of the second lens (602) may have a critical point from the optical axis to the end of the effective area. When the third surface (S3) has a critical point, it may be located in a range of 20% to 40%, preferably in a range of 25% to 35%, of the effective radius from the optical axis. The critical point of the third surface (S3) may be located in a range of 0.2 mm to 1.5 mm, preferably in a range of 0.5 mm to 1 mm from the optical axis. The critical point of the third surface (S3) may be a point where the sign of the gradient value with respect to the optical axis and the direction perpendicular to the optical axis changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the gradient value is 0. In addition, the critical point of the third surface (S3) may be a point where the gradient value of a tangent passing through the lens surface increases and then decreases, or a point where the gradient value decreases and then increases. The fourth surface (S4) of the second lens (602) can be provided without a critical point from the optical axis to the end of the effective area.

[0826] The aperture (Stop) may be arranged around the sensor-side fourth surface (S4) of the second lens (602). The aperture (Stop) may be arranged around the object-side fifth surface (S5) of the third lens (603). The aperture may move in the optical axis direction. The aperture may reduce the TTL within the field of view range, and may enable miniaturization of the optical system. Accordingly, a decrease in the yield by weight of the optical system may be prevented, and production efficiency may be improved.

[0827] The shapes of the lens surfaces facing the aperture can be formed similarly. The sign of the radius of curvature of the object-side surface of the second lens (602) in the object-side direction of the aperture and the sign of the radius of curvature of the sensor-side surface of the third lens (603) in the sensor-side direction of the aperture can be the same. This makes it possible to secure space between the lenses for arranging the aperture and the aperture drive device, and minimize interference in the operation of the aperture.

[0828]

[0829] The third lens (603) may be arranged third from the object side. The third lens (603) may be arranged fifth 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 plastic material.

[0830] 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 in which the sensor side is concave. The third lens (603) may have a meniscus shape in which the object side is convex. The third lens (603) may be made of a plastic material and may be aspherical. At least one or both of the fifth surface (S5) and the sixth surface (S6) may be aspherical. The aspherical coefficients of the fifth and sixth surfaces (S5, S6) may be provided as S1 and S2 of L3 in FIG. 45.

[0831] The fifth surface (S5) of the third lens (603) may have a critical point from the optical axis to the end of the effective area. When the fifth surface (S5) has a critical point, it may be located in a range of 60% to 80%, preferably in a range of 65% to 75%, of the effective radius from the optical axis. The critical point of the fifth surface (S5) may be located in a range of 0.5 mm to 2.0 mm, preferably in a range of 1 mm to 1.5 mm from the optical axis. The critical point of the fifth surface (S5) may be a point where the sign of the gradient value with respect to the optical axis and the direction perpendicular to the optical axis changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the gradient value is 0. In addition, the critical point of the fifth surface (S5) may be a point where the gradient value of a tangent passing through the lens surface increases and then decreases, or a point where the gradient value decreases and then increases.

[0832] The sixth surface (S6) of the third lens (603) may have a critical point from the optical axis to the end of the effective area. When the sixth surface (S6) has a critical point, it may be located in a range of 35% to 55%, preferably 40% to 50%, of the effective radius from the optical axis. The critical point of the sixth surface (S6) may be located in a range of 0.5 mm to 2 mm, preferably 0.8 mm to 1.3 mm from the optical axis. The critical point of the sixth surface (S6) may be a point where the sign of the gradient value with respect to the optical axis and the direction perpendicular to the optical axis changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the gradient value is 0. In addition, the critical point of the sixth surface (S6) may be a point where the gradient value of a tangent passing through the lens surface increases and then decreases, or a point where the gradient value decreases and then increases.

[0833]

[0834] The fourth lens (604) may be arranged fourth from the object side. The fourth lens (604) may be arranged fourth 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 negative (-) 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.

[0835] The seventh surface (S7) on the object side of the fourth lens (604) with respect to the optical axis may be convex, and the eighth surface (S8) on the sensor side may be concave. The fourth lens (604) may have a concave meniscus shape on the sensor side. The fourth lens (604) may have a convex meniscus shape on the object side. The fourth lens (604) may be made of a plastic material and may have an aspherical surface. 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. 45.

[0836] The seventh surface (S7) of the fourth lens (604) may have a critical point from the optical axis to the end of the effective area. When the seventh surface (S7) has a critical point, it may be located in a range of 35% to 55%, preferably 40% to 50%, of the effective radius from the optical axis. The critical point of the seventh surface (S7) may be located in a range of 0.3 mm to 1.5 mm, preferably 0.5 mm to 1.2 mm from the optical axis. The critical point of the seventh surface (S7) may be a point where the sign of the gradient value with respect to the optical axis and the direction perpendicular to the optical axis changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the gradient value is 0. In addition, the critical point of the seventh surface (S7) may be a point where the gradient value of a tangent passing through the lens surface increases and then decreases, or a point where the gradient value decreases and then increases.

[0837] The eighth surface (S8) of the fourth lens (604) may have a critical point from the optical axis to the end of the effective area. When the eighth surface (S8) has a critical point, it may be located in a range of 35% to 55%, preferably 40% to 50%, of the effective radius from the optical axis. The critical point of the eighth surface (S8) may be located in a range of 0.5 mm to 2 mm, preferably 1 mm to 1.8 mm from the optical axis. The critical point of the eighth surface (S8) may be a point where the sign of the gradient value with respect to the optical axis and the direction perpendicular to the optical axis changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the gradient value is 0. In addition, the critical point of the eighth surface (S8) may be a point where the gradient value of a tangent passing through the lens surface increases and then decreases, or a point where the gradient value decreases and then increases.

[0838]

[0839] The fifth lens (605) may be arranged as the fifth lens from the object side. The fifth lens (605) may be arranged as the third lens 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 positive (+) refractive power. The fifth lens (605) may include a plastic or glass material. For example, the fifth lens (605) may be provided as a plastic material.

[0840] 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 convex. The fifth lens (605) may have a meniscus shape in which the sensor side is convex. The fifth lens (605) may have a meniscus shape in which the object side is concave. The fifth lens (605) may be made of a plastic material and may have an aspherical surface. At least one of the ninth surface (S9) and the tenth surface (S10) may be an aspherical surface. The aspherical coefficients of the ninth and tenth surfaces (S9, S10) may be provided as S1 and S2 of L5 in FIG. 45. At least one or both of the ninth surface (S9) and the tenth surface (S10) of the fifth lens (605) may be provided without a critical point from the optical axis to the end of the effective area.

[0841]

[0842] The sixth lens (606) may be arranged as the sixth lens from the object side. The sixth lens (606) may be arranged as the second lens from the sensor side. The sixth lens (606) may be arranged between the fifth lens (605) and the seventh lens (607). The sixth lens (606) may have positive (+) or negative (-) refractive power on the optical axis (OA). The sixth lens (606) may have negative (-) refractive power. The sixth lens (606) may include a plastic or glass material. For example, the sixth lens (606) may be provided as a plastic material.

[0843] The object-side eleventh surface (S11) of the sixth lens (606) with respect to the optical axis may be convex, and the sensor-side twelfth surface (S12) may be concave. The sixth lens (606) may have a concave meniscus shape on the sensor side. The sixth lens (606) may have a convex meniscus shape on the object side. 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. 45.

[0844] The eleventh surface (S11) of the sixth lens (606) may have a critical point from the optical axis (OA) to the end of the effective area. When the eleventh surface (S11) has a critical point, it may be located in a range of 45% to 65%, preferably in a range of 50% to 60%, of the effective radius from the optical axis (OA). The critical point of the eleventh surface (S11) may be located in a range of 1 mm to 2.5 mm, preferably in a range of 1.5 mm to 2 mm from the optical axis (OA).

[0845] The critical point of the eleventh surface (S11) is a point where the sign of the slope value with respect to the optical axis (OA) and the direction perpendicular to the optical axis (OA) changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the slope value is 0. In addition, the critical point of the eleventh surface (S11) may be a point where the slope value of the tangent line passing through the lens surface increases and then decreases, or a point where the slope value decreases and then increases.

[0846] The twelfth surface (S12) of the sixth lens (606) may have 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 40% to 60%, preferably 45% to 55%, of the effective radius from the optical axis (OA). The critical point of the twelfth surface (S12) may be located in a range of 1 mm to 2.5 mm, preferably 1.5 mm to 2 mm, from the optical axis (OA).

[0847] The critical point of the 12th surface (S12) is a point where the sign of the slope value with respect to the optical axis (OA) and the direction perpendicular to the optical axis (OA) changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the slope value is 0. In addition, the critical point of the 12th surface (S12) may be a point where the slope value of the tangent line passing through the lens surface increases and then decreases, or a point where the slope value decreases and then increases.

[0848]

[0849] The seventh lens (607) may be arranged closest to the sensor side. The seventh lens (607) may be arranged farthest from the object side. The seventh lens (607) may have positive (+) or negative (-) refractive power on the optical axis (OA). The seventh lens (607) may have negative (-) refractive power. The seventh lens (607) may include a plastic or glass material. For example, the seventh lens (607) may be made of a plastic material.

[0850] The object-side 13th surface (S13) of the seventh lens (607) on the optical axis may be concave, and the sensor-side 14th surface (S14) may be concave. The seventh lens (607) may have a concave shape on both sides. At least one surface of the 13th surface (S13) and the 14th surface (S14) may be aspherical. For example, both the 13th surface (S13) and the 14th surface (S14) may be aspherical. The aspherical coefficients of the 13th and 14th surfaces (S13, S14) may be provided as S1 and S2 of L8 in FIG. 43. The 13th surface (S13) of the seventh lens (607) may be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0851] The fourteenth surface (S14) of the seventh lens (607) may have a critical point from the optical axis (OA) to the end of the effective area. When the fourteenth surface (S14) has a critical point, it may be located in a range of 30% to 50%, preferably 35% to 45%, of the effective radius from the optical axis (OA). The critical point of the fourteenth surface (S14) may be located in a range of 1 mm to 2.5 mm, preferably 1.5 mm to 2 mm, from the optical axis (OA).

[0852] The critical point of the 14th surface (S14) is a point where the sign of the slope value with respect to the optical axis (OA) and the direction perpendicular to the optical axis (OA) changes from positive (+) to negative (-) or from negative (-) to positive (+), and may mean a point where the slope value is 0. In addition, the critical point of the 14th surface (S14) may be a point where the slope value of the tangent line passing through the lens surface increases and then decreases, or a point where the slope value decreases and then increases.

[0853]

[0854] LensSurfaceRadiusThicknessndvdSemiApertureFocal length1S13.46480.84781.545956.09482.00008.6086 S212.04740.1753 1.9485 2S343.43930.30001.677619.24591.8521-72.1901 S422.9430 Variable (D1) 1.7190 Stop-Variable (D2) 1.3500 3S513.53900.48661.545956.09482.000077.8929 S619.61110.3977 2.1138 4S76.69850.32941.677619.24592.1732-30.8869 S84.97360.5451 2.5118 5S9-10.15740.90831.545956.09482.81087.1894 S10-2.96040.1193 3.1312 6S115.62430.68231.677619.24593.6902-34.9255 S124.32161.5539 4.0833 7S13-28.81090.50341.545956.09484.6819-6.7259 S144.23410.2697 5.6095 FilterS15 0.2400 6.1763 S16 0.4400 6.2435 Image 0.0000 6.4531

[0855]

[0856] Table 14 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 sixth embodiment of the present invention. At this time, the unit of the radius of curvature and thickness or distance may be mm.

[0857]

[0858] Mode 1 Mode 2 D10.12791.1279D21.00000.0000

[0859]

[0860] Table 15 shows the distance (D1, D2) between the lens and the aperture that is variable when the optical system according to the sixth embodiment of the present invention operates in either the first mode or the second mode. The aperture can be moved in the direction of the optical axis by the aperture device. As the aperture moves, the distance between adjacent lenses and the aperture can change. The aperture can be a moving group, and the lens unit can be a fixed group. The aperture can be arranged between the first lens group (LG1) and the second lens group (LG2). The aperture can be arranged between the second lens (602) and the third lens (603).

[0861] Here, the first mode means a state in which the aperture is placed adjacent to the lens placed on the object side among two adjacent lenses, and the second mode means a state in which the aperture is placed adjacent to the lens placed on the sensor side among two adjacent lenses.

[0862] When operating from the first mode to the second mode, the distance (D1) between the lens closest to the sensor side in the first lens group (LG1) and the aperture may increase, and the distance (D2) between the lens closest to the object side in the second lens group (LG2) and the aperture may decrease. When operating from the first mode to the second mode, the distance (D1) between the second lens (602) and the aperture may increase, and the distance (D2) between the third lens (603) and the aperture may decrease.

[0863] When operating from the second mode to the first mode, the distance (D1) between the lens closest to the sensor side in the first lens group (LG1) and the aperture may become smaller, and the distance (D2) between the lens closest to the object side in the second lens group (LG2) and the aperture may become larger. When operating from the second mode to the first mode, the distance (D1) between the second lens (602) and the aperture may become smaller, and the distance (D2) between the third lens (603) and the aperture may become larger.

[0864] The stroke length of the aperture may be shorter than the gap between the first lens group (LG1) and the second lens group (LG2). The stroke length of the aperture may be shorter than the gap between the second lens (602) and the third lens (603). The stroke length of the aperture may be in the range of 1 mm to 2 mm, and preferably in the range of 1.2 mm to 1.5 mm.

[0865] As the position of the aperture moves in the direction of the optical axis, the F-number, EPD, and SD of the optical system may change. The F-number may mean a value obtained by dividing the total focal length (F) by the diameter through which light passes (EPD). The EPD means the diameter through which light enters the optical system and may mean the entrance pupil. The SD may mean the distance from the aperture to the sensor side of the seventh lens (507) on the optical axis. In the first mode, the F-number may be maximum, and in the second mode, the F-number may be minimum. In the first mode, the EPD may be minimum, and in the second mode, the EPD may be maximum. In the first mode, the SD may be maximum, and in the second mode, the SD may be minimum.

[0866]

[0867] Item ValueItem ValueF7.0000ET10.3245ΣIndex11.2164ET20.3561ΣAbbe282.1169ET30.3021ΣCT4.0578ET40.4607ΣCG3.91 92ET50.3093CA_max10.2914ET60.4770CA_min3.5711ET71.4402CA_Aver5.7608F-number_12.2915CT_max0.9 083F-number_22.0116CT_min0.3000FOV_D79.9670CT_Aver0.5797FOV_H67.5848EPD_13.0548FOV_V53.8193 EPD_23.4317F_LG19.5782BFL0.9497F_LG2-100.3432TD7.9771SD_16.5261ImgH6.1500SD_25.5261TTL8.9268

[0868]

[0869] Table 16 shows the items of the mathematical formulas described above in the optical system (1500) of the embodiment, including the TTL (Total track length) (mm), BFL (Back focal length), effective focal length (F) (mm), ImgH (mm), effective diameter (CA) (mm), thickness (mm), TTL (mm), TD (mm), which is the optical axis distance from the first surface (S1) to the fourteenth surface (S14), SD_1 (mm), which is the optical axis distance from the stop (Stop) to the fourteenth surface (S14) in the first mode, SD_2 (mm), which is the optical axis distance from the stop (Stop) to the fourteenth surface (S14) in the second mode, EPD_1, which is the entrance pupil in the first mode, EPD_2, which is the entrance pupil in the second mode, F-number_1, which is the F-number in the first mode, F-number_2, which is the F-number in the second mode, sum of refractive indices, sum of Abbe numbers, sum of thickness (mm), It is about the sum of the gaps between adjacent lenses, the effective aperture characteristics, the diagonal field of view (FOV_D)(Degree), the vertical field of view (FOV_V)(Degree), the horizontal field of view (FOV_H)(Degree), the edge thickness (ET), etc. F_LG1 is the composite focal length of the first lens group (LG1)(mm), and F_LG2 is the composite focal length of the second lens group (LG2)(mm).

[0870]

[0871] The center thicknesses of the first to seventh lenses (601 to 607) are represented by CT1 to CT7, the edge thicknesses at the ends of the effective areas of each lens are represented by ET1 to ET7, the center gap between two adjacent lenses is represented by CG1 to CG6, and the edge gaps between the edges of each lens are represented by EG1 to EG7. 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).

[0872] As shown in Fig. 45, among the lenses of the lens unit of the sixth embodiment, the lens surfaces of the first to seventh lenses (601 to 607) may include aspherical surfaces having a 30th-order aspherical coefficient. For example, the first to seventh lenses (601 to 607) may include lens surfaces having a 30th-order aspherical coefficient. As described above, since the aspherical surface having a 30th-order aspherical coefficient (a value other than "0") can significantly change the aspherical shape of the periphery, the optical performance of the periphery of the field of view (FOV) can be well corrected.

[0873] When comparing the absolute values ​​of the curvature radii of each lens, the curvature radii of the thirteenth surface (S13) of the seventh lens (607) 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 (605) 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, 5 to 10 times. The curvature radii of the sensor-side surface of the fifth lens (605) may be the smallest among the lenses.

[0874] The absolute value of the curvature radius of the first surface (S1) of the first lens (601) may be smaller 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 larger 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 smaller 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 larger 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 larger 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 greater than the absolute value of the radius of curvature of the twelfth surface (S12). The absolute value of the radius of curvature of the thirteenth surface (S13) of the seventh lens (607) may be greater than the absolute value of the radius of curvature of the fourteenth surface (S14).

[0875] The ratio of the radius of curvature of each lens can satisfy the following conditions.

[0876] Condition 1: 0.1 < |L1R1 / L1R2| < 0.5

[0877] Condition 2: 1.5 < |L2R1 / L2R2| < 2

[0878] Condition 3: 0.5 < |L3R1 / L3R2| < 1

[0879] Condition 4: 1 < |L4R1 / L4R2| < 1.5

[0880] Condition 5: 3 < |L5R1 / L5R2| < 3.5

[0881] Condition 6: 1 < |L6R1 / L6R2| < 1.5

[0882] Condition 7: 5 < |L7R1 / L7R2| < 10

[0883]

[0884] When describing the central thickness of the lenses based on the optical axis, the central thickness (CT5) of the fifth lens (605) is the largest among the lenses, and the central thickness (CT2) of the second lens (602) is the smallest among the lenses. The difference between the maximum and minimum central thicknesses among the lenses may be in the range of 0.5 mm or more and 1 mm or less.

[0885] The central thickness of each lens may satisfy any one of the following conditions:

[0886] Condition 1: CT5 > CT1 > CT2, CT3, CT4, CT6, CT7

[0887] Condition 2: CT1, CT3, CT4, CT5, CT6, CT7 > CT2

[0888] Condition 3: CT1, CT5, CT6, CT7 > CT3 > CT2, CT4

[0889] Condition 4: CT1, CT3, CT5, CT6, CT7 > CT4 > CT2

[0890] Condition 5: CT5 > CT1, CT2, CT3, CT4, CT6, CT7

[0891] Condition 6: CT1, CT5 > CT6 > CT2, CT3, CT4, CT7

[0892] Condition 7: CT1, CT5, CT6 > CT7 > CT2, CT3, CT4

[0893]

[0894] When describing the center spacing (CG) between the lenses, the center spacing (CG6) between the sixth lens (606) and the seventh lens (607) may be the maximum, and the center spacing (CG5) between the fifth and sixth lenses (605, 606) may be the minimum. The difference between the maximum center spacing and the minimum center spacing among the spaced lens spacings may be 1 mm or more, for example, in the range of 1 mm to 1.5 mm.

[0895] The center spacing between each lens can satisfy the conditions below.

[0896] Condition 1: CG2, CG3, CG4, CG6 > CG1 > CG5

[0897] Condition 2: CG6 > CG2 > CG1, CG3, CG4, CG5

[0898] Condition 3: CG2, CG4, CG6 > CG3 > CG1, CG5

[0899] Condition 4: CG2, CG6 > CG4 > CG1, CG3, CG5

[0900] Condition 5: CG1, CG2, CG3, CG4, CG6 > CG5

[0901] Condition 6: CG6 > CG1, CG2, CG3, CG4, CG5

[0902]

[0903] Regarding the effective diameter, the lens with the maximum effective diameter may be the seventh lens (607) closest to the image sensor (700). The lens with the maximum effective diameter may be a plastic lens. 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 with the maximum effective diameter may be the fourteenth surface (S14) of the seventh lens (607).

[0904] The lens having the minimum effective diameter may be any one of the plastic material lenses, and for example, the effective diameter of the second lens (602) may be the minimum within the lens unit. The lens surface having the minimum effective diameter may be the fourth surface (S4) of the second lens (602).

[0905] The effective diameter of each lens can satisfy any one of the conditions below.

[0906] Condition 1: CA_L3, CA_L4, CA_L5, CA_L6, CA_L7 > CA_L1 > CA_L2

[0907] Condition 2: CA_L1, CA_L3, CA_L4, CA_L5, CA_L6, CA_L7 > CA_L2

[0908] Condition 3: CA_L4, CA_L5, CA_L6, CA_L7 > CA_L3 > CA_L1, CA_L2

[0909] Condition 4: CA_L5, CA_L6, CA_L7 > CA_L4 > CA_L1, CA_L2, CA_L3

[0910] Condition 5: CA_L6, CA_L7 > CA_L5 > CA_L1, CA_L2, CA_L3, CA_L4

[0911] Condition 6: CA_L7 > CA_L6 > CA_L1, CA_L2, CA_L3, CA_L4, CA_L5

[0912] Condition 7: CA_L7 > CA_L1, CA_L2, CA_L3, CA_L4, CA_L5, CA_L6

[0913]

[0914] Regarding the refractive index, the refractive index of the second lens (602), the fourth lens (604), and the sixth lens (606) may be the highest among the lenses and may be greater than 1.5, for example, greater than 1.6. The first lens (601), the third lens (603), the fifth lens (605), and the seventh lens (607) may have the lowest refractive index among the lenses. For example, the refractive index of the first lens (601), the third lens (603), the fifth lens (605), and the seventh lens (607) may be the lowest among the lenses and may be less than 1.6, for example, less than 1.55. The difference between the maximum refractive index and the minimum refractive index may be 0.1 or more.

[0915] The refractive index of each lens can satisfy any of the conditions below.

[0916] Condition 1: n2, n4, n6 > n1 = n3 = n5 = n7

[0917] Condition 2: n2 = n4 = n6 > n1, n3, n5, n7

[0918]

[0919] Comparing the Abbe numbers, the Abbe numbers of the first lens (601), the third lens (603), the fifth lens (605), and the seventh lens (607) are the largest among the lenses and may be 50 or more. The Abbe numbers of the second lens (602), the fourth lens (604), and the sixth lens (606) are the smallest among the lenses and may be 20 or less. The difference between the maximum Abbe number and the minimum Abbe number may be 30 or more.

[0920] The Abbe number of each lens can satisfy any of the conditions below.

[0921] Condition 1: v1 = v3 = v5 = v7 > v2, v4, v6

[0922] Condition 2: v1, v3, v5, v7 > v2 = v4 = v6

[0923]

[0924] The focal lengths (F2, F4, F6, F7) of the second, fourth, sixth, and seventh lenses (602, 604, 606, and 607) may have negative (-) signs. The second, fourth, sixth, and seventh lenses (602, 604, 606, and 607) may have negative (-) refractive power. The focal lengths (F1, F3, and F5) of the first, third, and fifth lenses (601, 603, and 605) may have positive (+) signs. The first, third, and fifth lenses (601, 603, and 605) may have positive (+) refractive power. The sixth and seventh lenses (606, 607) having negative (-) refractive power may be arranged on the sensor side of the fifth lens (605) having positive (+) refractive power. Through this, light incident from the object side can move closer to the optical axis and then move away from the optical axis again, thereby forming a stable optical path.

[0925]

[0926] When comparing the focal lengths in absolute values, the focal length of the third lens (603) is the largest among the lenses, and may be 50 or more and 100 or less. Among the lenses, the third lens (603) made of plastic may have the largest focal length and the smallest refractive power. The focal length of the seventh lens (607) is the smallest among the lenses, and the absolute value of the focal length of the seventh lens (607) may be 5 or more and 10 or less. Among the lenses, the fifth lens (605) made of plastic may have the smallest focal length and the largest refractive power.

[0927] Among the lenses, the lens having the minimum focal length may be the seventh lens (607). The difference between the maximum focal length and the minimum focal length may be 50 or more or 100 or more. Accordingly, the optical system may have improved MTF characteristics, aberration control characteristics, resolution characteristics, etc. in the set field of view range, and may have good optical performance in the periphery of the field of view.

[0928] The absolute value of the focal length of each lens can satisfy any of the conditions below.

[0929] Condition 1: |f2|, |f3|, |f4|, |f6| > |f1| > |f5|, |f7|

[0930] Condition 2: |f3| > |f2| > |f1|, |f4|, |f5|, |f6|, |f7|

[0931] Condition 3: |f3| > |f1|, |f2|, |f4|, |f5|, |f6|, |f7|

[0932] Condition 4: |f2|, |f3|, |f6| > |f4| > |f1|, |f5|, |f7|

[0933] Condition 5: |f1|, |f2|, |f3|, |f4|, |f6| > |f5| > |f7|

[0934] Condition 6: |f2|, |f3| > |f6| > |f1|, |f4|, |f5|, |f7|

[0935] Condition 7: |f1|, |f2|, |f3|, |f4|, |f5|, |f6| > |f7|

[0936]

[0937] The thickness (T1) of the first lens (601) may be minimum at the edge and maximum at the center, and the maximum thickness is in the range of 2.5 to 3 times the minimum thickness. The thickness (T2) of the second lens (602) may be maximum at the edge and minimum at the center, and the maximum thickness is in the range of 1 to 1.5 times the minimum thickness. The thickness (T3) of the third lens (603) may be maximum at the center and minimum at the edge, and the maximum thickness is in the range of 1.5 to 2 times the minimum thickness. The thickness (T4) of the fourth lens (604) may be minimum at the center and maximum at the edge, and the maximum thickness is in the range of 1 to 1.5 times the minimum thickness. The thickness (T5) of the fifth lens (605) may be maximum at the center and minimum at the edge, and the maximum thickness is in the range of 2.5 to 3 times the minimum thickness. The thickness (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 1 to 1.5 times the minimum thickness. The thickness (T7) of the seventh lens (607) may be minimum at the center and maximum at the edge, and the maximum thickness is in the range of 2.5 to 3 times the minimum thickness.

[0938] The thickness of each lens can satisfy any of the conditions below.

[0939] Condition 1: 2.5 < CT1 / ET1 < 3, 0.1 < ET1 / CT1 < 0.5

[0940] Condition 2: 0.5 < CT2 / ET2 < 1, 1 < ET2 / CT2 < 1.5

[0941] Condition 3: 1.5 < CT3 / ET3 < 2, 0.5 < ET3 / CT3 < 1

[0942] Condition 4: 0.5 < CT4 / ET4 < 1, 1 < ET4 / CT4 < 1.5

[0943] Condition 5: 2.5 < CT5 / ET5 < 3, 0.1 < ET5 / CT5 < 0.5

[0944] Condition 6: 1 < CT6 / ET6 < 1.5, 0.5 < ET6 / CT6 < 1

[0945] Condition 7: 0.1 < CT7 / ET7 < 0.5, 2.5 < ET7 / CT7 < 3

[0946] Condition 8: 1 < ΣCT / ΣET < 1.5, 0.5 < ΣET / ΣCT < 1

[0947]

[0948] Among the gaps (G1-G6) between the lenses, the first gap (G1) between the first and second lenses (601, 602) may have a minimum in the center and a maximum in the edge. The second gap (G2) between the second and third lenses (602, 603) may have a minimum in the edge and a maximum in the center. The third gap (G3) between the third and fourth lenses (603, 604) may have a minimum in the edge and a maximum in the center. The fourth gap (G4) between the fourth and fifth lenses (604, 605) may have a minimum in the edge and a maximum 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. The sixth gap (G6) between the sixth and seventh lenses (606, 607) may have a maximum in the center and a minimum in the edge.

[0949]

[0950] The optical systems (1000, 1100, 1200, 1300) according to the first to fourth 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) according to the first to fourth embodiments can have improved optical characteristics. For example, when the optical systems (1000, 1100, 1200, 1300) satisfy at least one mathematical equation, the optical systems (1000, 1100, 1200, 1300) can effectively control aberration characteristics such as chromatic aberration and distortion aberration, and can have good optical performance not only at the center of the field of view (FOV) but also at the periphery. In addition, the optical systems (1000, 1100, 1200, 1300) can have improved resolution. In addition, the thickness of the lens on the optical axis (OA) and the spacing between adjacent lenses on the optical axis (OA) described in the mathematical formulas may refer to the first to fourth embodiments disclosed above.

[0951]

[0952] [Mathematical Formula 1]

[0953] 0.1 < L2R2 / L3R1 < 3

[0954] In mathematical expression 1, L2R2 is the radius of curvature of the sensor-side surface (fourth surface (S4)) of the second lens (102, 202, 302, 402), and L3R1 is the radius of curvature of the object-side surface (fifth surface (S5)) of the third lens (103, 203, 303, 403). When mathematical expression 1 is satisfied, the aperture (STOP) is arranged between the second lens (102, 202, 302, 402) and the third lens (103, 203, 303, 403), and the shape of the lens surface facing the aperture (STOP) can be formed similarly. Through this, the driving interference of the aperture (STOP) can be minimized. If it is less than the lower limit of mathematical expression 1, it is difficult to arrange the aperture (STOP) and aperture drive device between the lenses, and if it is more than 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 and second embodiments, mathematical expression 1 may preferably satisfy 2 < L2R2 / L3R1 < 2.5. In the third and fourth embodiments, mathematical expression 1 may preferably satisfy 0.3 < L2R2 / L3R1 < 0.7.

[0955]

[0956] [Equation 2]

[0957] 0.3 < CT2 / CG2 < 1

[0958] In mathematical expression 2, CT2 is the center thickness of the second lens (102, 202, 302, 402), and CG2 is the center spacing between the second lens (102, 202, 302, 402) and the third lens (103, 203, 303, 403). When mathematical expression 2 is satisfied, the center spacing between the second lens (102, 202, 302, 402) and the third lens (103, 203, 303, 403) where the aperture (STOP) is arranged can be appropriately set. When it is less than the lower limit of mathematical expression 1, it is difficult to arrange the aperture (STOP) and the aperture drive device between the lenses, and when it exceeds the upper limit of mathematical expression 1, the lenses may have long effective diameters or TTLs, which may cause a problem of the imaging lens system becoming larger. In the first and second embodiments, mathematical expression 2 preferably satisfies 0.3 < CT2 / CG2 < 0.8. In the third and fourth embodiments, mathematical expression 2 preferably satisfies 0.3 < CT2 / CG2 < 0.5.

[0959]

[0960] [Equation 3]

[0961] 0.3 < EG2 < 1.0

[0962] In mathematical expression 3, EG2 is the edge gap between the second lens (102, 202, 302, 402) and the third lens (103, 203, 303, 403). EG2 may mean the distance between the effective aperture end of the sensor-side (fourth surface (S4)) of the second lens (102, 202, 302, 402) and the effective aperture end of the object-side (fifth surface (S5)) of the third lens (103, 203, 303, 403). When mathematical expression 3 is satisfied, the gap between adjacent lenses can be appropriately designed to secure space for diaphragm (STOP) arrangement, and the driving interference of the diaphragm (STOP) can be minimized. If it is less than the lower limit of mathematical expression 3, it may be difficult to arrange the aperture (STOP) and aperture drive device between the lenses, and if it is more than the upper limit of mathematical expression 3, 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 and second embodiments, mathematical expression 3 may preferably satisfy 0.4 < EG2 < 0.6. In the third and fourth embodiments, mathematical expression 3 may preferably satisfy 0.5 < EG2 < 1.

[0963]

[0964] [Equation 4]

[0965] 0.5 < EG2 / CG2 < 2

[0966] In mathematical expression 4, EG2 is the edge spacing between the second lens (102, 202, 302, 402) and the third lens (103, 203, 303, 403), and CG2 is the center spacing between the second lens (102, 202, 302, 402) and the third lens (103, 203, 303, 403). When mathematical expression 4 is satisfied, the space for arranging the aperture (STOP) can be secured by appropriately designing the spacing between adjacent lenses, and the driving interference of the aperture (STOP) can be minimized. When it is less than the lower limit of mathematical expression 3, it is difficult to arrange the aperture (STOP) and the aperture driving device between the lenses, and when it exceeds the upper limit of mathematical expression 3, the lenses may have long effective diameters or TTLs, which may cause a problem of the imaging lens system becoming larger. In the first and second embodiments, mathematical expression 4 can preferably satisfy 1 < EG2 / CG2 < 1.8. In the third and fourth embodiments, mathematical expression 4 can preferably satisfy 0.5 < EG2 / CG2 < 1.

[0967]

[0968] [Equation 5]

[0969] 0.01 < CT2 / ΣCT < 0.1

[0970] In mathematical expression 5, CT2 is the central thickness of the second lens (102, 202, 302, 402), and ΣCT is the sum of the central thicknesses of the lenses. When mathematical expression 5 is satisfied, the light emitted from the second lens (102, 202, 302, 402), which is adjacent to the aperture (STOP) and has a large influence on the entire optical system, sets an optical path that is incident on the remaining lenses, and the optical system can have good optical performance at the set angle of view and focal length. In the first and second embodiments, mathematical expression 5 can preferably satisfy 0.03 < CT2 / ΣCT < 0.08. In the third and fourth embodiments, mathematical expression 5 can preferably satisfy 0.05 < CT2 / ΣCT < 0.08.

[0971]

[0972] [Equation 6]

[0973] 0.01 < CT3 / ΣCT < 0.3

[0974] In mathematical expression 6, CT3 is the central thickness of the third lens (103, 203, 303, 403), and ΣCT is the sum of the central thicknesses of the lenses. When mathematical expression 6 is satisfied, the light emitted from the third lens (103, 203, 303, 403), which is adjacent to the aperture (STOP) and has a large influence on the entire optical system, sets an optical path that is incident on the remaining lenses, and the optical system can have good optical performance at the set angle of view and focal length. In the first and second embodiments, mathematical expression 6 can preferably satisfy 0.04 < CT3 / ΣCT < 0.06. In the third and fourth embodiments, mathematical expression 6 can preferably satisfy 0.1 < CT3 / ΣCT < 0.15.

[0975]

[0976] [Equation 7]

[0977] 0.01 < CG2 / ΣCG < 0.5

[0978] In mathematical expression 7, CG2 is the center spacing between the second lens (102, 202, 302, 402) and the third lens (103, 203, 303, 403), and ΣCG is the sum of the spacings between adjacent lenses. When mathematical expression 7 is satisfied, the spacing between adjacent lenses can be appropriately designed to secure space for diaphragm (STOP) arrangement, and the driving interference of the diaphragm (STOP) can be minimized. When it is less than the lower limit of mathematical expression 7, it is difficult to arrange the diaphragm (STOP) and the diaphragm driving device between the lenses, and when it is more than the upper limit of mathematical expression 7, the lenses may have long effective diameters or TTLs, which may cause a problem of the imaging lens system becoming larger. In the first and second embodiments, mathematical expression 7 may preferably satisfy 0.05 < CG2 / ΣCG < 0.15. In the third and fourth embodiments, mathematical expression 7 can preferably satisfy 0.3 < CG2 / ΣCG < 0.5.

[0979]

[0980] [Equation 8]

[0981] 0.1 < |LG1_F / LG2_F| < 0.8

[0982] In mathematical expression 8, LG1_F is the composite focal length of the first lens group (LG1), and LG2_F is the composite focal length of the second lens group (LG2). When mathematical expression 8 is satisfied, the light path incident in the entire optical system is set, and the optical system can have good optical performance at the set angle of view and focal length. In the first and second embodiments, mathematical expression 8 can preferably satisfy 0.4 < |LG1_F / LG2_F| < 0.5. In the third and fourth embodiments, mathematical expression 8 can preferably satisfy 0.2 < |LG1_F / LG2_F| < 0.4.

[0983]

[0984] [Equation 9]

[0985] 0.5 < F / TTL < 1

[0986] In mathematical expression 9, 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) to the upper surface of the image sensor (700). When mathematical expression 9 is satisfied, the optical system (1000, 1100, 1200, 1300) can have an appropriate focal length in the set TTL range. When it is less than the lower limit of mathematical expression 9, the refractive power of the lenses needs to be increased, making it difficult to correct spherical aberration or distortion aberration, and when it is more than the upper limit of mathematical expression 9, the effective diameter or TTL of the lenses may become long, which may cause a problem in that the imaging lens system becomes large. In the first and second embodiments, mathematical expression 9 can preferably satisfy 0.6 < F / TTL < 0.8. In the third and fourth embodiments, mathematical expression 9 can preferably satisfy 0.5 < F / TTL < 0.8.

[0987]

[0988] [Equation 10]

[0989] 1 < TTL / ImgH < 1.5

[0990] In mathematical expression 10, TTL (Total track length) means the distance (mm) from the vertex of the first surface (S1) of the first lens (101, 201, 301, 401) to the upper surface of the image sensor (700) on the optical axis (OA), and ImgH means 1 / 2 of the maximum diagonal length of the image sensor (700). When mathematical expression 10 is satisfied, the optical system (1000, 1100, 1200, 1300) can have TTL for application to the image sensor (700), thereby providing improved image quality. When it is less than the lower limit of mathematical expression 10, the refractive power of the lenses needs to be increased, making it difficult to correct spherical aberration or distortion aberration, and when it is more than the upper limit of mathematical expression 10, the effective diameter or TTL of the lenses may become longer, which may cause a problem in that the imaging lens system becomes larger. In the first and second embodiments, mathematical expression 10 can preferably satisfy 1.3 < TTL / ImgH < 1.5. In the third and fourth embodiments, mathematical expression 10 can preferably satisfy 1 < TTL / ImgH < 1.5.

[0991]

[0992] [Equation 11]

[0993] 1 < F1 / F < 1.5

[0994] In mathematical expression 11, F1 is the focal length of the first lens (101, 201, 301, 401), and F is the effective focal length of the optical system. When mathematical expression 11 is satisfied, the optical system (1000, 1100, 1200, 1300) can have a set angle of view and an appropriate focal length. 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) having positive (+) refractive power. When it is below the lower limit of mathematical expression 11, the lenses may have long effective diameters or TTLs, which may cause a problem of the imaging lens system becoming larger. If the upper limit of mathematical expression 11 is exceeded, the influence of the first lens (101, 201, 301, 401) 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 and second embodiments, mathematical expression 11 can preferably satisfy 1 < F1 / F < 1.2. In the third and fourth embodiments, mathematical expression 11 can preferably satisfy 1 < F1 / F < 1.3.

[0995]

[0996] [Equation 12]

[0997] 4 < |F2| / F < 7

[0998] In mathematical expression 12, F2 is the focal length of the second lens (102, 202, 302, 402), and F is the effective focal length of the optical system. When mathematical expression 12 is satisfied, the optical system (1000, 1100, 1200, 1300) can have a set angle of view and an appropriate focal length. When it is less than the lower limit of mathematical expression 12, 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 more than the upper limit of mathematical expression 12, the influence of the second lens (102, 202, 302, 402) becomes small in the entire optical system, 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 and second embodiments, mathematical expression 12 may preferably satisfy 4 < |F2| / F < 4.6. In the third and fourth embodiments, mathematical expression 12 can preferably satisfy 3 < |F2| / F < 6.

[0999]

[1000] [Equation 13]

[1001] 3 < |F3| / F < 18

[1002] In mathematical expression 13, F3 is the focal length of the third lens (103, 203, 303, 403), and F is the effective focal length of the optical system. When mathematical expression 13 is satisfied, the optical system (1000, 1100, 1200, 1300) can have a set angle of view and an appropriate focal length. When it is less than the lower limit of mathematical expression 13, 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 more than the upper limit of mathematical expression 13, the influence of the third lens (103, 203, 303, 403) 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 and second embodiments, mathematical expression 13 can preferably satisfy 13 < |F3| / F < 14.5. In the third and fourth embodiments, mathematical expression 13 preferably satisfies 4 < |F3| / F < 8.

[1003]

[1004] [Equation 14-1]

[1005] 0.1 < |F8| / F < 1

[1006] In mathematical expression 14-1, F8 is the focal length of the eighth lens (108, 208), and F is the effective focal length of the optical system (1000, 1100). When mathematical expression 14-1 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 14-1, 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 14-1, the influence of the eighth lens (108, 208) 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 and second embodiments, mathematical expression 14-1 may preferably satisfy 0.4 < |F8| / F < 0.7.

[1007]

[1008] [Equation 14-2]

[1009] 0.1 < |F7| / F < 1

[1010] In mathematical expression 14-2, F7 is the focal length of the seventh lens (307, 407), and F is the effective focal length of the optical system (1200, 1300). When mathematical expression 14-2 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 14-2, 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 14-2, the influence of the seventh lens (307, 407) 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 third and fourth embodiments, mathematical expression 14-2 may preferably satisfy 0.5 < |F7| / F < 1.

[1011]

[1012] [Equation 15]

[1013] 1.5 < n1 < 1.6

[1014] In mathematical expression 15, n1 is the refractive index of the first lens (101, 201, 301, 401). When mathematical expression 15 is satisfied, the refractive index of the first lens (101, 201, 301, 401) arranged closest to the object side in the optical system (1000, 1100, 1200, 1300) can have a high refractive index, thereby minimizing chromatic aberration. In the first to fourth embodiments, mathematical expression 15 can preferably satisfy 1.52 < n1 < 1.58.

[1015]

[1016] [Equation 16]

[1017] 0.5 < CT_Max / CG_Max < 1.5

[1018] In mathematical expression 16, CT_Max is the maximum center 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 a focal length at a set angle of view, and can reduce TTL. In the first and second embodiments, mathematical expression 16 can preferably satisfy 0.6 < CT_Max / CG_Max < 0.9. In the third and fourth embodiments, mathematical expression 16 can preferably satisfy 0.5 < CT_Max / CG_Max < 1.2.

[1019]

[1020] [Equation 17]

[1021] 2 < CA_max / CA_min < 3

[1022] 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 and second embodiments, mathematical expression 17 can preferably satisfy 2.4 < CA_max / CA_min < 2.8. In the third and fourth embodiments, mathematical expression 17 can preferably satisfy 2.5 < CA_max / CA_min < 2.9.

[1023]

[1024] [Equation 18]

[1025] 0.5 < ΣCG / ΣCT < 1

[1026] 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 a focal length at a set angle of view, and can reduce the TTL. In the first and second embodiments, mathematical expression 18 can preferably satisfy 0.7 < ΣCG / ΣCT < 1. In the third and fourth embodiments, mathematical expression 18 can preferably satisfy 0.5 < ΣCG / ΣCT < 0.7.

[1027]

[1028] [Equation 19]

[1029] 0.5 < CA_L1 / F < 1

[1030] In mathematical expression 19, CA_L1 is the effective diameter of the first lens (101, 201, 301, 401), and F is the effective focal length of the optical system. If it is less than the lower limit of mathematical expression 19, the effective diameter of the lens arranged in the optical system (1000, 1100, 1200, 1300) becomes the largest, which causes a problem in that the TTL becomes long. If it exceeds the upper limit of mathematical expression 19, there is a problem in that the angle of view becomes excessively larger than that satisfied by the optical system (1000, 1100, 1200, 1300). In the first and second embodiments, mathematical expression 19 can preferably satisfy 0.5 < CA_L1 / F < 0.8. In the third and fourth embodiments, mathematical expression 19 can preferably satisfy 0.5 < CA_L1 / F < 0.7.

[1031]

[1032] [Equation 20]

[1033] 1 < F / EPD < 2

[1034] In mathematical expression 20, F is the effective focal length of the optical system, and EPD represents the diameter of the entrance pupil (effective aperture). When mathematical expression 20 is satisfied, an image with an appropriate brightness can be provided, and a lot of light can be received by the image sensor. In the first and second embodiments, mathematical expression 20 can preferably satisfy 1.3 < F / EPD < 1.8. In the third and fourth embodiments, mathematical expression 20 can preferably satisfy 0.8 < F / EPD < 1.8.

[1035]

[1036] [Equation 21]

[1037] 0.1 < BFL / TTL < 0.3

[1038] In mathematical expression 21, BFL means the optical axis distance from the image sensor (700) 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) to the upper surface of the image sensor (700). When mathematical expression 21 is satisfied, the optical system (1000, 1100, 1200, 1300) can have a set angle of view and an appropriate focal length, and a mobile optical system can be provided. In addition, the optical system (1000, 1100, 1200, 1300) can minimize the gap between the last lens and the image sensor (700), and thus can have good optical characteristics at the periphery of the field of view (FOV). In the first to fourth embodiments, mathematical expression 21 can preferably satisfy 0.1 < BFL / TTL < 0.2.

[1039]

[1040] [Equation 22]

[1041] 80 < FOV_D < 90

[1042] In mathematical expression 22, FOV_H represents the diagonal angle of view (Degree) of the optical system (1000, 1100, 1200, 1300), and can provide an angle of view suitable for a mobile optical system. In the first and second embodiments, it is preferable that 81 < FOV_D < 83 is satisfied. In the third and fourth embodiments, it is preferable that 80 < FOV_D < 90 is satisfied.

[1043]

[1044] [Equation 23]

[1045] 0.1 < TTL / CA_max < 1

[1046] In mathematical expression 23, TTL (Total track length) means the distance (mm) from the vertex of the first surface (S1) of the first lens (101, 201, 301, 401) to the upper surface of the image sensor (700) 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 23 is satisfied, the optical system can maintain good optical performance and set a size for a slim and compact structure. In the first and second embodiments, mathematical expression 23 can preferably satisfy 0.5 < TTL / CA_max < 0.9. In the third and fourth embodiments, mathematical expression 23 can preferably satisfy 0.5 < TTL / CA_max < 1.

[1047]

[1048] [Equation 24]

[1049] 8 < TTL < 9.5

[1050] In mathematical expression 24, TTL (Total track length) means the distance (mm) from the center of the first surface (S1) of the first lens (101, 201, 301, 401) to the upper surface of the image sensor (700) on the optical axis (OA). When mathematical expression 24 is satisfied, a suitable mobile optical system can be provided. In the first and second embodiments, mathematical expression 24 can preferably satisfy 8.5 < TTL < 9. In the third and fourth embodiments, mathematical expression 24 can preferably satisfy 8 < TTL < 10.

[1051]

[1052] [Equation 25]

[1053] 5.5 < ImgH < 6.5

[1054] Mathematical expression 25 indicates that ImgH represents half of the maximum diagonal length of the image sensor (700). Mathematical expression 25 can set the diagonal size of the image sensor (700) and provide an optical system having a mobile sensor size. In the first and second embodiments, Mathematical expression 25 can preferably satisfy 6 < ImgH < 6.5. In the third and fourth embodiments, Mathematical expression 25 can preferably satisfy 5 < ImgH < 7.

[1055]

[1056] [Equation 26]

[1057] 0.5 < BFL < 1.5

[1058] In mathematical expression 26, BFL is the optical axis distance from the image sensor (700) to the center of the sensor side of the last lens. When mathematical expression 26 is satisfied, the installation space for the filter and cover glass can be secured, the assembling of the components can be improved through the gap between the image sensor (700) and the last lens, and the joint reliability can be improved. When the BFL is less than the range of mathematical expression 26, some of the light that proceeds to the image sensor may not be transmitted to the image sensor, which may cause a decrease in resolution. When the BFL exceeds the range of mathematical expression 26, stray light may be introduced, which may deteriorate the aberration characteristics of the optical system. In the first and second embodiments, mathematical expression 26 may preferably satisfy 0.8 < BFL < 1.3. In the third and fourth embodiments, mathematical expression 26 may preferably satisfy 1 < BFL < 1.5.

[1059]

[1060] [Equation 27]

[1061] 5 < F < 7

[1062] Mathematical expression 27 can set the overall focal length (F) to suit the mobile optical system. In the first and second embodiments, Mathematical expression 27 can preferably satisfy 6.5 < F < 7. In the third and fourth embodiments, Mathematical expression 27 can preferably satisfy 6 < F < 7.

[1063]

[1064] Table 18 shows the result values ​​for the mathematical expressions 1 to 27 described above in the optical system (1000, 1100, 1200, 1300) of the embodiment. Referring to Table 18, it can be seen that the optical system (1000, 1100, 1200, 1300) satisfies at least one, two or more, or three or more of the mathematical expressions 1 to 27. In detail, it can be seen that the optical system (1000, 1100, 1200, 1300) according to the embodiment satisfies all of the mathematical expressions 1 to 27. Accordingly, the optical system (1000, 1100, 1200, 1300) can have good optical performance at the center and periphery of the field of view (FOV) and can have excellent optical characteristics.

[1065]

[1066] Mathematical Formula 1 Example 2 Example 3 Example 4 Example 10.1 < L2R2 / L3R1 < 32.43262.19980.50720.308520.3 < CT2 / CG2 < 10.78180.45610.31620.301130.3 < EG2 < 1.00.48580.55840.81950.888640.5 < EG2 / CG2 < 21.65121.10730.86370.891850.01 < CT2 / ΣCT < 0.10.05630.05260.06560.062760.01 < CT3 / ΣCT < 0.30.05630.05260.13810.140670.01 < CG2 / ΣCG < 0.50.08610.13940.31290.327280.1 < |LG1_F / LG2_F| < 0.80.42630.44780.28180.322890.5 < F / TTL < 10.79470.76730.77930.7533101 < TTL / ImgH < 1.51.40981.45991.41461.3953111 < F1 / F < 1.51.10061.17191.10591.1298124 < |F2| / F < 74.13094.57624.47955.6550133 < |F3| / F < 1813.709814.29386.92297.143614-10.1 < |F8| / F < 10.59070.6055--14-20.1 < |F7| / F < 1--0.97160.5835151.5 < n1 < 1.61.54681.54681.54591.5468160.5 < CT_Max / CG_Max < 1.50.83750.79180.72391.1338172 < CA_max / CA_min < 32.61922.52432.79682.6474180.5 < ΣCG / ΣCT < 10.83710.82650.66290.6368190.5 < CA_L1 / F < 10.63310.69900.55190.5782201 < F / EPD < 21.60001.40001.00001.7800210.1 < BFL / TTL < 0.30.12790.10260.12580.13032280 < FOV_D < 9082.585982.125286.000082.6000230.1 < TTL / CA_max < 10.87560.88220.89680.9159248 < TTL < 9.58.60008.90558.70009.0000255.5 < ImgH < 6.56.10006.10006.15006.4500260.5 < BFL < 1.51.10000.91331.09471.1727275 < F < 76.83406.83366.78006.7800.

[1067]

[1068] The optical systems (1400, 1500) according to the fifth and sixth embodiments disclosed above can satisfy at least one or two or more of the mathematical equations described below. Accordingly, the optical systems (1400, 1500) according to the fifth and sixth embodiments can have improved optical characteristics. For example, when the optical systems (1400, 1500) satisfy at least one mathematical equation, the optical systems (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 but also at the periphery of the field of view (FOV). In addition, the optical systems (1400, 1500) can have improved resolution. In addition, the thickness of the lens on the optical axis (OA) described in the mathematical equations and the spacing between adjacent lenses on the optical axis (OA) may refer to the fifth and sixth embodiments disclosed above.

[1069]

[1070] [Equation 28]

[1071] 0.01 < |LG1_F / LG2_F| < 0.2

[1072] In mathematical expression 28, LG1_F is the composite focal length of the first lens group (LG1), and LG2_F is the composite focal length of the second lens group (LG2). When mathematical expression 28 is satisfied, the light path incident on the entire optical system is set, and the optical system can have good optical performance at the set angle of view and focal length. In addition, the refractive power of the first lens group (LG1) can be designed to be stronger than the refractive power of the second lens group (LG2), so that the influence on the F number according to the position of the aperture can be designed to be large. In the fifth and sixth embodiments, mathematical expression 28 can preferably satisfy 0.08 < |LG1_F / LG2_F| < 0.2.

[1073]

[1074] [Equation 29]

[1075] 0.2 < CG2 / ΣCG < 0.5

[1076] In mathematical expression 29, CG2 is the center spacing between the second lens (502, 602) and the third lens (503, 603), and ΣCG is the sum of the spacings between adjacent lenses. When mathematical expression 29 is satisfied, the spacing between adjacent lenses can be appropriately designed to secure space for diaphragm (STOP) arrangement, and the driving interference of the diaphragm (STOP) can be minimized. When it is less than the lower limit of mathematical expression 29, it is difficult to arrange the diaphragm (STOP) and the diaphragm driving device between the lenses, and when it is more than the upper limit of mathematical expression 29, the lenses may have long effective diameters or TTLs, which may cause a problem of a large-sized imaging lens system. In the fifth and sixth embodiments, mathematical expression 29 may preferably satisfy 0.25 < CG2 / ΣCG < 0.5.

[1077]

[1078] [Equation 30]

[1079] 0.2 < CG2 / ΣCT < 0.5

[1080] In mathematical expression 30, CG2 is the center spacing between the second lens (502, 602) and the third lens (503, 603), and ΣCT is the sum of the center thicknesses of the lenses. When mathematical expression 30 is satisfied, the space for arranging the aperture (STOP) can be secured by appropriately designing the spacing between adjacent lenses, and the driving interference of the aperture (STOP) can be minimized. When it is less than the lower limit of mathematical expression 30, it is difficult to arrange the aperture (STOP) and the aperture driving device between the lenses, and when it is more than the upper limit of mathematical expression 30, 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. In the fifth and sixth embodiments, mathematical expression 30 can preferably satisfy 0.2 < CG2 / ΣCT < 0.4.

[1081]

[1082] [Equation 31]

[1083] 0.1 < CG2 / TTL < 0.3

[1084] In mathematical expression 31, CG2 is the center spacing between the second lens (502, 602) and the third lens (503, 603), and TTL (Total track length) means the distance (mm) from the vertex of the first surface (S1) of the first lens (501, 601) to the upper surface of the image sensor (700) on the optical axis (OA). When mathematical expression 31 is satisfied, the space for arranging the aperture (STOP) can be secured by appropriately designing the spacing between adjacent lenses, and the driving interference of the aperture (STOP) can be minimized. When it is less than the lower limit of mathematical expression 31, it is difficult to arrange the aperture (STOP) and the aperture driving device between the lenses, and when it exceeds the upper limit of mathematical expression 31, the lenses may have long effective diameters or TTLs, which may cause a problem of the imaging lens system becoming larger. In the fifth and sixth embodiments, mathematical expression 31 can preferably satisfy 0.1 < CG2 / TTL < 0.3.

[1085]

[1086] [Equation 32]

[1087] 1 < LG1_F / F < 1.5

[1088] In mathematical expression 32, LG1_F is the focal length of the first lens group (G1), and F is the effective focal length of the optical system. When mathematical expression 32 is satisfied, the influence on the F number as the aperture moves in the optical axis direction can be designed to be large. When it is below the lower limit of mathematical expression 32, the effective diameter or TTL may become long, which may cause a problem of the imaging lens system becoming large. When it exceeds the upper limit of mathematical expression 32, the refractive power of the first lens group (LG1) is designed to be weak, so that the change in the F number according to the change in the aperture position may be minimal. In the fifth and sixth embodiments, mathematical expression 32 can preferably satisfy 1.2 < LG1_F / F < 1.4.

[1089]

[1090] [Equation 33]

[1091] 5 < |LG2_F| / F < 15

[1092] In mathematical expression 33, LG2_F is the focal length of the second lens group (G2), and F is the effective focal length of the optical system. When mathematical expression 33 is satisfied, the influence on the F number as the aperture moves in the optical axis direction can be designed to be large. When it is below the lower limit of mathematical expression 33, the effective diameter or TTL may become longer, which may cause a problem of the large size of the imaging lens system. When it is above the upper limit of mathematical expression 33, the refractive power of the first lens group (LG1)...

Claims

1. Including first to eighth lenses arranged along the optical axis, The above fifth lens has a negative (-) refractive power, The above sixth lens has positive (+) refractive power, The above seventh lens has positive (+) refractive power, The above eighth lens has a negative (-) refractive power, The sign of the curvature radius of the sensor side of the second lens and the sign of the curvature radius of the object side of the third lens are the same optical system.

2. In paragraph 1, An optical system in which the thickness of the second lens among the first to eighth lenses on the optical axis is the smallest.

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

4. In paragraph 1, An optical system in which an aperture is placed between the second lens and the third lens.

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

6. In paragraph 1, An optical system in which the thickness of the first lens among the first to eighth lenses on the optical axis is the greatest.

7. In any one of paragraphs 1 to 6, An optical system that satisfies the following conditions. <Conditional expression> 8 < TTL < 9.5 (In the above conditional expression, TTL means the distance on the optical axis from the object side of the first lens to the upper surface of the image sensor.) 8. In any one of paragraphs 1 to 6, An optical system that satisfies the following conditions. <Conditional expression> 2 < L2R2 / L3R1< 3 (In the above conditional expression, L2R2 represents the radius of curvature of the sensor side of the second lens, and L3R1 represents the radius of curvature of the object side of the third lens.) 9. Including the first to eighth lenses arranged along the optical axis, The above fifth lens has a negative (-) refractive power, The above sixth lens has positive (+) refractive power, The above seventh lens has positive (+) refractive power, The above eighth lens has a negative (-) refractive power, An optical system in which the thickness of the first lens among the first to eighth lenses on the optical axis is the greatest.

10. In paragraph 9, An optical system in which the thickness of the third lens among the first to eighth lenses on the optical axis is the smallest.

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