Optical system and camera module

Abstract

An optical system according to one embodiment of the present invention includes first to eighth lenses disposed along an optical axis, wherein the fifth lens has positive (+) 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 absolute value of the focal length of the eighth lens among the fifth to eighth lenses is the smallest.

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 an optical system and camera module with improved optical characteristics.

[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 the present embodiment includes first to eighth 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 positive (+) refractive power, and the eighth lens has negative (-) refractive power, and among the fifth to eighth lenses, the absolute value of the focal length of the eighth lens is the smallest.

[0008] Among the first to fourth lenses, the absolute value of the focal length of the first lens may be the smallest.

[0009] The first lens may have positive (+) refractive power, the second lens may have negative (-) refractive power, and the refractive index of the first lens may be less than the refractive index of the second lens.

[0010] Among the center spacings of adjacent lenses, the center spacing between the first lens and the second lens may be the smallest.

[0011] Among the first to eighth lenses on the optical axis, the thickness of the second lens may be the smallest.

[0012] The third lens may have positive (+) refractive power, and the fourth lens may have negative (-) refractive power.

[0013]

[0014] *The following condition can be satisfied. <Condition> 9 < 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.)

[0015] The following condition can be satisfied. <Condition> 0.1 < CG1+CG2+CG3+CG4 / CG5+CG6+CG7 < 0.5 (In the above condition, CGn is the center distance between the nth lens and the n+1th lens.)

[0016] 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 positive (+) 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 among the first to eighth lenses, the absolute value of the focal length of the first lens may be the smallest.

[0017] The refractive index of the first lens may be smaller than the refractive index of the second lens.

[0018] The first lens may have positive (+) refractive power, and the second lens may have negative (-) refractive power.

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

[0020] The following condition can be satisfied. <Condition> 3 < CA_L8 / CA_L1 < 3.5 (In the above condition, CA_L1 means the effective diameter of the first lens, and CA_L8 means the effective diameter of the eighth lens.)

[0021] The following condition can be satisfied. <Condition> 0.1 < CA_L1 / ImgH < 0.5 (In the above condition, CA_L1 means the effective diameter of the first lens, and ImgH means the maximum diagonal length of the image sensor.)

[0022] The following condition can be satisfied. <Condition> 0.5 < CA_L8 / ImgH < 1 (In the above condition, CA_L8 means the effective diameter of the eighth lens, and ImgH means the maximum diagonal length of the image sensor.)

[0023] An optical system and camera module according to an embodiment may have improved optical characteristics. Specifically, in the optical system according to an embodiment, a plurality of lenses may have set thicknesses, refractive powers, and spacings from adjacent lenses. Accordingly, the optical system and camera module according to the embodiment may have improved MTF characteristics, aberration control characteristics, resolution characteristics, etc. within a set field of view range, and may have good optical performance in the periphery of the field of view.

[0024] 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.

[0025] FIG. 1 is a side cross-sectional view of an optical system and a camera module having the same according to a first embodiment.

[0026] Fig. 2 is a table showing the aspherical coefficients of the first to eighth lenses in the optical system of Fig. 1.

[0027] 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.

[0028] Figure 4 is a table showing the spacing between the first to eighth lenses in the optical system of Figure 1.

[0029] 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.

[0030] Figure 6 is a graph showing data on the diffraction MTF (Modulation Transfer Function) of the optical system of Figure 1.

[0031] Fig. 7 is a graph showing data on the aberration characteristics of the optical system of Fig. 1.

[0032] Fig. 8 is a side cross-sectional view of an optical system and a camera module having the same according to a second embodiment.

[0033] Fig. 9 is a table showing the aspherical coefficients of the first to eighth lenses in the optical system of Fig. 8.

[0034] Fig. 10 is a table showing the Sag values ​​of the lens surfaces of the first to eighth lenses in the optical system of Fig. 8.

[0035] Fig. 11 is a table showing the spacing between the first to eighth lenses in the optical system of Fig. 8.

[0036] Fig. 12 is a table showing the slope angles of the lens surfaces of the first to eighth lenses in the optical system of Fig. 8.

[0037] Figure 13 is a graph showing data on the diffraction MTF (Modulation Transfer Function) of the optical system of Figure 8.

[0038] Fig. 14 is a graph showing data on the aberration characteristics of the optical system of Fig. 8.

[0039] Figure 15 is an exploded perspective view of a camera module according to the present embodiment.

[0040] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings.

[0041] 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.

[0042] 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.

[0043] Additionally, the terms used in this embodiment are for the purpose of describing the embodiments and are not intended to limit the present invention.

[0044] 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.

[0045] 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.

[0046] 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.

[0047] 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.

[0048] 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.

[0049]

[0050] An optical system according to a first embodiment of the invention will be described.

[0051] FIG. 1 is a side cross-sectional view of an optical system according to a first embodiment and a camera module having the same, FIG. 2 is a table showing aspherical coefficients of first to eighth lenses in the optical system of FIG. 1, FIG. 3 is a table showing Sag values ​​of lens surfaces of the first to eighth lenses in the optical system of FIG. 1, FIG. 4 is a table showing spacings between the first to eighth lenses in the optical system of FIG. 1, FIG. 5 is a table showing Slope angles of lens surfaces of the first to eighth lenses in the optical system of FIG. 1, FIG. 6 is a graph showing data on diffraction MTF (Modulation Transfer Function) of the optical system of FIG. 1, and FIG. 7 is a graph showing data on aberration characteristics of the optical system of FIG. 1.

[0052] 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 about an object may pass through the first lens (101) to the eighth lens (108) and a filter (400) and be incident on the image sensor (300).

[0053] 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 L2 in FIG. 2.

[0054] 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.

[0055] At least one or both of the first surface (S1) and the second surface (S2) of the first lens (101) can be provided without a critical point from the optical axis to the end of the effective area.

[0056] An aperture (stop) may be arranged around the object-side first surface (S1) of the first lens (101). The aperture can reduce the TTL within the field of view range, enabling miniaturization of the optical system. Accordingly, a decrease in the yield by weight of the optical system can be prevented, and production efficiency can be improved. In addition, the optical system can be miniaturized by reducing the TTL within the field of view (FOV) of 80 to 90 degrees.

[0057]

[0058] 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.

[0059] 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.

[0060] At least one or both of the third surface (S3) and the fourth surface (S4) of the second lens (102) can be provided without a critical point from the optical axis to the end of the effective area.

[0061]

[0062] 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 positive (+) refractive power on the optical axis (OA). The third lens (103) may include a plastic or glass material. For example, the third lens (103) may be provided as a plastic material.

[0063] 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.

[0064] At least one or both of the fifth side (S5) and the sixth side (S6) can be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0065]

[0066] The fourth lens (104) may be arranged fourth from the object side. The fourth lens (104) may be arranged fifth from the sensor side. The fourth lens (104) may be arranged between the third lens (103) and the fifth lens (105). The fourth lens (104) may have positive (+) or negative (-) refractive power on the optical axis (OA). The fourth lens (104) may have negative (-) refractive power. Unlike the refractive power of the fifth lens (105), the fourth lens (104) may have negative (-) refractive power. The fourth lens (104) may include a plastic or glass material. For example, the fourth lens (104) may be provided with a plastic material.

[0067] The seventh surface (S7) on the object side of the fourth lens (104) with respect to the optical axis may be convex, and the eighth surface (S8) on the sensor side may be concave. The fourth lens (104) may have a concave meniscus shape on the sensor side. The fourth lens (104) may have a convex meniscus shape 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.

[0068] The seventh surface (S7) of the fourth lens (104) 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 20% to 40%, preferably 30% to 35%, of the effective radius from the optical axis. The critical point of the seventh surface (S7) may be located in a range of 0.1 mm to 1 mm, preferably 0.5 mm to 0.8 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.

[0069] The eighth surface (S8) of the fourth lens (104) 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 30% to 50%, preferably 35% to 45%, 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 1.5 mm, preferably 0.6 mm to 0.9 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.

[0070]

[0071]

[0072] The fifth lens (105) may be arranged as the fifth lens from the object side. The fifth lens (105) may be arranged as the fourth lens from the sensor side. The fifth lens (105) may be arranged between the fourth lens (104) and the sixth lens (106). The fifth lens (105) may have positive (+) or negative (-) refractive power on the optical axis (OA). The fifth lens (105) may have positive (+) refractive power. Unlike the refractive power of the fourth lens (104), the fifth lens (105) may have positive (+) refractive power. The fifth lens (105) may include a plastic or glass material. For example, the fifth lens (105) may be provided as a plastic material. The fifth lens (105) may be provided as the same material as the sixth lens (106).

[0073] With respect to the optical axis (OA), the ninth surface (S9) on the object side of the fifth lens (105) may be concave, and the tenth surface (S10) on the sensor side may be convex. The fifth lens (105) may have a meniscus shape in which the sensor side is convex. The fifth lens (105) may have a meniscus shape in which the object side is concave. 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.

[0074] The ninth surface (S9) of the fifth lens (105) 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 80% to 99%, preferably 90% to 98%, of the effective radius from the optical axis. The critical point of the ninth surface (S9) may be located in a range of 1.5 mm to 2.3 mm, preferably 2 mm to 2.3 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.

[0075] The tenth surface (S10) of the fifth lens (105) may have a critical point from the optical axis to the end of the effective area. When the tenth surface (S10) has a critical point, it may be located in a range of 80% to 99%, preferably 95% to 99%, of the effective radius from the optical axis. The critical point of the tenth surface (S10) may be located in a range of 1.5 mm to 2.6 mm, preferably 2.3 mm to 2.6 mm from the optical axis. The critical point of the tenth surface (S10) 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 tenth surface (S10) 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.

[0076]

[0077] 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.

[0078] With respect to the optical axis (OA), the eleventh surface (S11) on the object side of the sixth lens (106) may be convex, and the twelfth surface (S12) on the sensor side may be concave. The sixth lens (106) may have a concave meniscus shape on the sensor side. The sixth lens (106) 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. 2.

[0079] The eleventh surface (S11) of the sixth lens (106) may have a critical point from the optical axis to the end of the effective area. When the eleventh surface (S11) has a critical point, it may be located in a range of 20% to 40%, preferably 30% to 35%, of the effective radius from the optical axis. The critical point of the eleventh surface (S11) may be located in a range of 0.5 mm to 1.5 mm, preferably 0.7 mm to 1.3 mm from the optical axis. The critical point of the eleventh surface (S11) 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 eleventh surface (S11) 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.

[0080] The twelfth surface (S12) of the sixth lens (106) may have a critical point from the optical axis to the end of the effective area. When the twelfth surface (S12) has a critical point, it may be located in a range of 15% to 30%, preferably 20% to 25%, of the effective radius from the optical axis. The critical point of the twelfth surface (S12) may be located in a range of 0.5 mm to 1.5 mm, preferably 0.7 mm to 1.3 mm from the optical axis. The critical point of the twelfth surface (S12) 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 twelfth surface (S12) 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.

[0081]

[0082] 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.

[0083] The object-side 13th surface (S13) of the seventh lens (107) with respect to the optical axis may be convex, and the sensor-side 14th surface (S14) may be concave. The seventh lens (107) may have a concave meniscus shape on the sensor side. The seventh lens (107) may have a convex meniscus shape on the object side. 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.

[0084] The thirteenth surface (S13) of the seventh lens (107) may have a critical point from the optical axis to the end of the effective area. When the thirteenth surface (S13) has a critical point, it may be located in a range of 20% to 40%, preferably 30% to 35%, of the effective radius from the optical axis. The critical point of the thirteenth surface (S13) may be located in a range of 1.0 mm to 2.0 mm, preferably 1.2 mm to 1.8 mm from the optical axis. The critical point of the thirteenth surface (S13) 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 thirteenth surface (S13) 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.

[0085] The fourteenth surface (S14) of the seventh lens (107) may have a critical point from the optical axis to the end of the effective area. When the fourteenth surface (S14) has a critical point, it may be located in a range of 20% to 40%, preferably in a range of 30% to 40%, of the effective radius from the optical axis. The critical point of the fourteenth surface (S14) may be located in a range of 1.0 mm to 2.5 mm, preferably in a range of 1.5 mm to 2.3 mm from the optical axis. The critical point of the fourteenth surface (S14) 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 fourteenth surface (S14) 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.

[0086]

[0087] 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.

[0088] 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 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. 9.

[0089] The 15th surface (S15) of the 8th lens (108) can be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0090] 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 10% to 30%, preferably in a range of 20% to 28%, 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).

[0091] 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.

[0092]

[0093] LensSurfaceRadiusThicknessndvdSemiApertureFocal length1S1(Stop)2.84490.97791.546256.33152.06107.3190 S28.66700.0350 1.9592 2S37.18440.25031.677619.23851.9234-18.0670 S44.46370.2903 1.7776 3S58.21080.45841.546256.33151.763032.1620 S615.11150.4794 1.7627 4S734.08770.33831.677619.23851.8000-59.6440 S818.41670.0990 2.0198 5S9-87.39200.67181.546256.33152.325034.3030 S10-15.47170.8023 2.6264 6S1122.12650.67231.619325.95022.8905342.2540 S1224.41870.7071 3.6800 7S135.83011.01971.569737.55104.5533103.3230 S146.06010.6699 5.1318 8S15-13.63910.71001.536655.71036.0760-8.6590 S167.17440.1083 6.4456 IRS17infinity0.2100 7.4691 S18infinity0.7637 7.5625 Image infinity0.0063 8.1660

[0094] 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.

[0095]

[0096] Item ValueItem ValueF8.1600ET10.3500ΣIndex12.7194ET20.3730ΣAbbe326.6830ET30.3420ΣCT4.0733ET 40.3190ΣCG3.8785ET50.5040CA_max12.5216ET60.7410CA_min3.5257ET70.6060CA_Aver6. 0994ET80.7150CT_max0.9779FOV_D88.7091CT_min0.0990LG1_F10.9447CT_Aver0.5092LG2 _F-38.8683EPD4.1220ImgH16.3320BFL1.0883SD8.2900TD8.1817TTL9.2700F-number1.9796

[0097] Table 2 shows the items of the mathematical formulas described above in the optical system (1000) of the embodiment, including the total track length (TTL) (mm), back focal length (BFL), effective focal length (F) (mm), ImgH (mm), effective diameter (CA) (mm), thickness (mm), TTL (mm), the optical axis distance from the first surface (S1) to the sixteenth surface (S16) TD (mm), the optical axis distance from the aperture (Stop) to the sixteenth surface (S16) SD (mm), the sum of refractive indices, the sum of Abbe numbers, the sum of thicknesses (mm), the sum of spacings between adjacent lenses, effective diameter characteristics, the diagonal angle of view (FOV_D) (Degree), the edge thickness (ET), the F number, etc. of the optical system (1000). LG1_F is the composite focal length of the first lens group (LG1) (mm), and LG2_F is the composite focal length of the second lens group (LG2) (mm).

[0098] 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 (300) 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 (300).

[0099] 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).

[0100] When comparing the absolute values ​​of the curvature radii of each lens, the curvature radii of the ninth surface (S9) of the fifth lens (105) on the optical axis (OA) may be the largest among the lenses, and the curvature radii of the first surface (S1) of the first lens (101) may be the smallest among the lenses. The difference between the maximum curvature radii and the minimum curvature radii may be 30 times or more, for example, in the range of 30 to 40 times. The curvature radii of the object-side surface of the first lens (101) arranged on the object-side of the second lens (102) may be the smallest among the lenses.

[0101] 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 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 (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 smaller than the absolute value of the curvature radius of the twelfth surface (S12). The absolute value of the curvature radius of the thirteenth surface (S13) of the seventh lens (107) may be smaller 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 larger than the absolute value of the curvature radius of the sixteenth surface (S16).

[0102] The ratio of the radius of curvature of each lens can satisfy the following conditions.

[0103] Condition 1: 0.1 < |L1R1 / L1R2| < 0.5

[0104] Condition 2: 1.5 < |L2R1 / L2R2| < 2

[0105] Condition 3: 0.5 < |L3R1 / L3R2| < 1

[0106] Condition 4: 1.5 < |L4R1 / L4R2| < 2

[0107] Condition 5: 5.5 < |L5R1 / L5R2| < 6

[0108] Condition 6: 0.5 < |L6R1 / L6R2| < 1

[0109] Condition 7: 0.5 < |L7R1 / L7R2| < 1

[0110] Condition 8: 1.5 < |L8R1 / L8R2| < 2

[0111]

[0112] When describing the central thickness of the lenses based on the optical axis, the central thickness (CT7) of the seventh lens (107) is the largest among the lenses, and the central thickness (CT2) of the second lens (102) 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.

[0113] The central thickness of each lens may satisfy any one of the following conditions:

[0114] Condition 1: CT7 > CT1 > CT2, CT3, CT4, CT5, CT6, CT8

[0115] Condition 2: CT1, CT4, CT3, CT5, CT6, CT7, CT8 > CT2

[0116] Condition 3: CT1, CT5, CT6, CT7, CT8 > CT3 > CT2, CT4

[0117] Condition 4: CT1, CT3, CT5, CT6, CT7, CT8 > CT4 > CT2

[0118] Condition 5: CT1, CT6, CT7, CT8 > CT5 > CT2, CT3, CT4

[0119] Condition 6: CT1, CT7, CT8 > CT6 > CT2, CT3, CT4, CT5

[0120] Condition 7: CT7 > CT1, CT2, CT3, CT4, CT5, CT6, CT8

[0121] Condition 8: CT1, CT7 > CT8 > CT2, CT3, CT4, CT5, CT6

[0122]

[0123] When describing the center spacing (CG) between the lenses, the center spacing (CG6) between the sixth lens (106) and the seventh lens (107) 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 0.5 mm or more, for example, in the range of 0.5 mm to 1.0 mm.

[0124] The center spacing between each lens can satisfy the conditions below.

[0125] Condition 1: CG2, CG3, CG4, CG5, CG6, CG7 > CG1

[0126] Condition 2: CG3, CG4, CG5, CG6, CG7 > CG2 > CG1

[0127] Condition 3: CG4, CG5, CG6, CG7 > CG3 > CG2, CG1

[0128] Condition 4: CG5, CG6, CG7 > CG4 > CG1, CG2, CG3

[0129] Condition 5: CG6, CG7 > CG5 > CG1, CG2, CG3, CG4

[0130] Condition 6: CG6 > CG1, CG2, CG3, CG4, CG5, CG7

[0131] Condition 7: CG6 > CG7 > CG1, CG2, CG3, CG4, CG5

[0132]

[0133] Regarding the effective diameter, the lens with the maximum effective diameter may be the eighth lens (108) closest to the image sensor (300). 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).

[0134] 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).

[0135] The effective diameter of each lens can satisfy any one of the conditions below.

[0136] Condition 1: CA_L5, CA_L6, CA_L7, CA_L8 > CA_L1 > CA_L2, CA_L3, CA_L4

[0137] Condition 2: CA_L1, CA_L4, CA_L5, CA_L6, CA_L7, CA_L8 > CA_L2 > CA_L3

[0138] Condition 3: CA_L1, CA_L2, CA_L4, CA_L5, CA_L6, CA_L7, CA_L8 > CA_L3

[0139] Condition 4: CA_L1, CA_L5, CA_L6, CA_L7, CA_L8 > CA_L4 > CA_L2, CA_L3

[0140] Condition 5: CA_L6, CA_L7, CA_L8 > CA_L5 > CA_L1, CA_L2, CA_L3, CA_L4

[0141] Condition 6: CA_L7, CA_L8 > CA_L6 > CA_L1, CA_L2, CA_L3, CA_L4, CA_L5

[0142] Condition 7: CA_L8 > CA_L7 > CA_L1, CA_L2, CA_L3, CA_L4, CA_L5, CA_L6

[0143] Condition 8: CA_L8 > CA_L1, CA_L2, CA_L3, CA_L4, CA_L5, CA_L6, CA_L7

[0144]

[0145] Regarding the refractive index, the refractive index of the second lens (102) and the fourth lens (104) may be the highest among the lenses and may be greater than 1.5, for example, greater than 1.6. The eighth lens (108) may have the lowest refractive index among the lenses. For example, the refractive index of the eighth lens (108) 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.

[0146] The refractive index of each lens can satisfy any of the conditions below.

[0147] Condition 1: n2, n4, n6, n7 > n1 = n3 = n5 > n8

[0148] Condition 2: n2 = n4 > n1, n3, n5, n6, n7, n8

[0149] Condition 3: n2, n4 > n6 > n1, n3, n5, n7, n8

[0150] Condition 4: n2, n4, n6 > n7 > n1, n3, n5, n8

[0151] Condition 5: n1, n2, n3, n4, n5, n6, n7 > n8

[0152]

[0153] Comparing the Abbe numbers, the Abbe numbers of the first lens (101), the third lens (103), and the fifth lens (105) are the largest among the lenses and may be 50 or more. The Abbe numbers of the second lens (102) and the fourth lens (104) 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.

[0154] The Abbe number of each lens can satisfy any of the conditions below.

[0155] Condition 1: v1 = v3 = v5 > v8, v7, v6, v2, v4

[0156] Condition 2: v1, v3, v5, v6, v7, v8 > v2 = v4

[0157] Condition 3: v1, v3, v5, v7, v8 > v6 > v2, v4

[0158] Condition 4: v1, v3, v5, v8 > v7 > v2, v4, v6

[0159] Condition 5: v1, v3, v5 > v8 > v2, v4, v6, v7

[0160]

[0161] The focal lengths (F2, F4, F8) of the 2nd, 4th, and 8th lenses (102, 104, and 108) may have negative (-) signs. The 2nd, 4th, and 8th lenses (102, 104, and 108) may have negative (-) refractive power. The focal lengths (F1, F3, F5, F6, and F7) of the 1st, 3rd, 5th, 6th, and 7th lenses (101, 103, 105, 106, and 107) may have positive (+) signs. The 1st, 3rd, 5th, 6th, and 7th lenses (101, 103, 105, 106, and 107) may have positive (+) refractive power.

[0162] The first lens (101) and the second lens (102), which are adjacently arranged lenses, can satisfy the following conditions.

[0163] Condition 1: Refractive index of lens with positive refractive power < refractive index of lens with negative refractive power

[0164] Condition 2: Dispersion of a lens with positive refractive power > Dispersion of a lens with negative refractive power

[0165] Here, among the plastic lenses, the first lens (101) has negative refractive power and the second lens (102) has positive refractive power, so that according to conditions 1 and 2, the refractive index of the first lens (101) is greater than the refractive index of the second lens (102), and the dispersion value of the first lens (101) is less than the dispersion value of the second lens (102). The chromatic aberration occurring in the plastic lens can be corrected by the plastic lens. In addition, since the first lens (101) and the second lens (102), which are plastic lenses arranged in succession, satisfy the conditions of a refractive index difference of 0.1 or more and 0.15 or less and an Abbe number difference of 20 or more and 50 or less, the chromatic aberration occurring in the plastic lens can be compensated for by the plastic lens.

[0166] Optical systems suffer from chromatic aberration, and this can be corrected using cemented lenses or two lenses positioned in series. Since lenses made of the same material exhibit the same degree of change in their characteristics with temperature, it is effective to compensate for chromatic aberration between lenses made of the same material, even when the temperature changes. Therefore, in the first embodiment of the present invention, the first lens (101) and the second lens (102) are used to correct chromatic aberration occurring in a plastic lens.

[0167]

[0168] When comparing the focal lengths in absolute values, the focal length of the sixth lens (106) is the largest among the lenses, and may be 300 or more and 400 or less. Among the lenses, the sixth lens (106) made of plastic may have the largest focal length and the smallest refractive power. The focal length of the first lens (101) is the smallest among the lenses, and the absolute value of the focal length of the first lens (101) may be 5 or more and 10 or less. Among the lenses, the first lens (101) made of plastic may have the smallest focal length and the largest refractive power.

[0169] Among the lenses, the lens having the minimum focal length may be the first lens (101). The difference between the maximum focal length and the minimum focal length may be 300 or more or 350 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.

[0170] Among the first to fourth lenses (101-104) arranged adjacent to the object side, the absolute value of the focal length of the first lens (101) may be the smallest. Among the first to fourth lenses (101-104) arranged adjacent to the object side, the refractive power of the first lens (101) may be the largest. Through this, light incident on the optical system (1000) may be appropriately refracted to secure optical performance.

[0171] Among the fifth to eighth lenses (105-108) arranged adjacent to the image sensor (300), the absolute value of the focal length of the eighth lens (108) may be the smallest. Among the fifth to eighth lenses (105-108) arranged adjacent to the image sensor (300), the refractive power of the eighth lens (108) may be the largest. Through this, the impact on optical performance when the eighth lens (108) arranged closest to the image sensor (300) shakes can be minimized.

[0172] The absolute value of the focal length of each lens can satisfy any of the conditions below.

[0173] Condition 1: |f2|, |f3|, |f4|, |f5|, |f6|, |f7|, |f8| > |f1|

[0174] Condition 2: |f3|, |f4|, |f5|, |f6|, |f7| > |f2| > |f1|, |f8|

[0175] Condition 3: |f4|, |f5|, |f6|, |f7| > |f3| > |f1|, |f2|, |f8|

[0176] Condition 4: |f6|, |f7| > |f4| > |f1|, |f2|, |f3|, |f5|, |f8|

[0177] Condition 5: |f4|, |f6|, |f7| > |f5| > |f1|, |f2|, |f3|, |f8|

[0178] Condition 6: |f6| > |f1|, |f2|, |f3|, |f4|, |f5|, |f7|, |f8|

[0179] Condition 7: |f6| > |f7| > |f1|, |f2|, |f3|, |f4|, |f5|, |f8|

[0180] Condition 8: |f2|, |f3|, |f4|, |f5|, |f6|, |f7| > |f8| > |f1|

[0181]

[0182] Among the lenses, the first lens (101) positioned closest to the object side may have the greatest refractive power. Among the lenses, the first lens (101) positioned closest to the object side may have the shortest focal length. The lens positioned closest to the image sensor (300) has a problem in that it shakes, resulting in a large change in optical performance. Therefore, by positioning the lens with the greatest refractive power closest to the object side, the stability of performance changes after manufacturing can be secured.

[0183] At least two of the fifth to eighth lenses (105-108) arranged adjacent to the sensor side may have positive refractive power. For example, the fifth to seventh lenses (105, 106, 107) may have positive refractive power, and the eighth lens (108) may have negative refractive power. By designing the refractive power of a plurality of lenses adjacent to the image sensor (300) to be positive refractive power, the MTF resolution of the optical system (1000) can be improved, and the amount of lens curvature can be reduced. The amount of lens curvature refers to a phenomenon in which light rays passing through a lens are bent rather than focused on an ideal imaging plane. The amount of lens curvature can occur because the image sensor is flat. The amount of lens curvature can increase as the curvature of the lens increases.

[0184]

[0185] 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 2 to 3 times the minimum thickness. The thickness (T2) of the second lens (102) may be maximum at the edge and minimum at the center, and the maximum thickness is in the range of 1 to 1.5 times the minimum thickness. The thickness (T3) of the third lens (103) may be maximum at the center and minimum at the edge, and the maximum thickness is in the range of 1 to 1.5 times the minimum thickness. The thickness (T4) of the fourth lens (104) may be maximum at the center and minimum at the edge, and the maximum thickness is in the range of 1 to 1.5 times the minimum thickness. The thickness (T5) of the fifth lens (105) may be maximum at the center and minimum at the edge, and the maximum thickness is in the range of 1 to 1.5 times the minimum thickness. The thickness (T6) of the sixth lens (106) 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 (107) 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 (108) may be minimum at the center and maximum at the edge, and the maximum thickness is in the range of 1 to 1.2 times the minimum thickness.

[0186] The thickness of each lens can satisfy any of the conditions below.

[0187] Condition 1: 2.5 < CT1 / ET1 < 3, 0.1 < ET1 / CT1 < 0.5

[0188]

[0189] Condition 2: 0.5 < CT2 / ET2 < 1, 1 < ET2 / CT2 < 1.5

[0190] Condition 3: 1 < CT3 / ET3 < 1.5, 0.5 < ET3 / CT3 < 1

[0191] Condition 4: 1 < CT4 / ET4 < 1.5, 0.5 < ET4 / CT4 < 1

[0192] Condition 5: 1 < CT5 / ET5 < 1.5, 0.5 < ET5 / CT5 < 1

[0193] Condition 6: 0.5 < CT6 / ET6 < 1, 1 < ET6 / CT6 < 1.5

[0194] Condition 7: 1.5 < CT7 / ET7 < 2, 0.3 < ET7 / CT7 < 0.8

[0195] Condition 8: 0.5 < CT8 / ET8 < 1, 1 < ET8 / CT8 < 1.2

[0196] Condition 9: 1 < ΣCT / ΣET < 1.5, 0.5 < ΣET / ΣCT < 1

[0197]

[0198] Among the gaps (G1-G7) between the lenses, the first gap (G1) between the first and second lenses (101, 102) may have a minimum in the center and a maximum in the edge. The second gap (G2) between the second and third lenses (102, 103) may have a minimum in the edge and a maximum 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 fourth 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.

[0199]

[0200] An optical system according to a second embodiment of the invention will be described.

[0201] FIG. 8 is a side cross-sectional view of an optical system according to a second embodiment and a camera module having the same, FIG. 9 is a table showing aspherical coefficients of the first to eighth lenses in the optical system of FIG. 8, FIG. 10 is a table showing Sag values ​​of lens surfaces of the first to eighth lenses in the optical system of FIG. 8, FIG. 11 is a table showing spacings between the first to eighth lenses in the optical system of FIG. 8, FIG. 12 is a table showing Slope angles of lens surfaces of the first to eighth lenses in the optical system of FIG. 8, FIG. 13 is a graph showing data on diffraction MTF (Modulation Transfer Function) of the optical system of FIG. 8, and FIG. 14 is a graph showing data on aberration characteristics of the optical system of FIG. 8.

[0202] Referring to FIG. 8, 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 the filter (400) and be incident on the image sensor (300).

[0203] The first lens (201) can be arranged closest to the object side. The first lens (201) can be arranged farthest from the sensor side. In addition, the optical system can be miniaturized by reducing the TTL at an angle of view (FOV) of 70 to 90 degrees. The first lens (201) can have positive refractive power on the optical axis (OA). The first lens (201) can include a plastic material or a glass material, and can be, for example, a plastic material. At least one or both of the first surface (S1) and the second surface (S2) can be aspherical. The aspherical coefficients of the first and second surfaces (S1, S2) can be provided as S1 and S2 of L2 in FIG. 9. The first lens (201) made of a plastic material can reduce changes in the center position and the radius of curvature due to temperature changes in the surrounding environment, and can protect the incident surface of the optical system (1100).

[0204] 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.

[0205] At least one or both of the first surface (S1) and the second surface (S2) of the first lens (201) can be provided without a critical point from the optical axis to the end of the effective area.

[0206]

[0207] 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.

[0208] The third surface (S3) on the object side of the second lens (202) 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 (202) may have a concave meniscus shape toward the sensor side. 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. 9.

[0209] At least one or both of the third surface (S3) and the fourth surface (S4) of the second lens (202) can be provided without a critical point from the optical axis to the end of the effective area.

[0210]

[0211] 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 positive (+) refractive power on the optical axis (OA). The third lens (203) may include a plastic or glass material. For example, the third lens (203) may be provided as a plastic material.

[0212] 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) 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. 9.

[0213] At least one or both of the fifth side (S5) and the sixth side (S6) can be provided without a critical point from the optical axis (OA) to the end of the effective area.

[0214]

[0215] The fourth lens (204) may be arranged fourth from the object side. The fourth lens (204) may be arranged fifth from the sensor side. The fourth lens (204) may be arranged between the third lens (203) and the fifth lens (205). The fourth lens (204) may have positive (+) or negative (-) refractive power on the optical axis (OA). The fourth lens (204) may have negative (-) refractive power. Unlike the refractive power of the fifth lens (205), the fourth lens (204) may have negative (-) refractive power. The fourth lens (204) may include a plastic or glass material. For example, the fourth lens (204) may be provided with a plastic material.

[0216] The seventh surface (S7) on the object side of the fourth lens (204) with respect to the optical axis may be convex, and the eighth surface (S8) on the sensor side may be concave. The fourth lens (204) may have a concave meniscus shape on the sensor side. The fourth lens (204) may have a convex meniscus shape 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. 9.

[0217] The seventh surface (S7) of the fourth lens (204) 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 20% to 40%, preferably in a range of 25% to 35%, of the effective radius from the optical axis. The critical point of the seventh surface (S7) may be located in a range of 0.1 mm to 1 mm, preferably in a range of 0.3 mm to 0.8 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.

[0218] The eighth surface (S8) of the fourth lens (204) 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 30% to 50%, preferably 35% to 45%, 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 1.5 mm, preferably 0.6 mm to 0.9 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.

[0219]

[0220] The fifth lens (205) may be arranged as the fifth lens from the object side. The fifth lens (205) may be arranged as the fourth lens from the sensor side. The fifth lens (205) may be arranged between the fourth lens (204) and the sixth lens (206). The fifth lens (205) may have positive (+) or negative (-) refractive power on the optical axis (OA). The fifth lens (205) may have positive (+) refractive power. Unlike the refractive power of the fourth lens (204), the fifth lens (205) may have positive (+) refractive power. The fifth lens (205) may include a plastic or glass material. For example, the fifth lens (205) may be provided as a plastic material. The fifth lens (205) may be provided as the same material as the sixth lens (206).

[0221] With respect to the optical axis (OA), the ninth surface (S9) on the object side of the fifth lens (205) may be concave, and the tenth surface (S10) on the sensor side may be convex. The fifth lens (205) may have a meniscus shape in which the sensor side is convex. The fifth lens (205) may have a meniscus shape in which the object side is concave. 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. 9.

[0222] The ninth surface (S9) of the fifth lens (205) can be provided without a critical point from the optical axis to the end of the effective area.

[0223] The tenth surface (S10) of the fifth lens (205) may have a critical point from the optical axis to the end of the effective area. When the tenth surface (S10) has a critical point, it may be located in a range of 80% to 99%, preferably 90% to 99%, of the effective radius from the optical axis. The critical point of the tenth surface (S10) may be located in a range of 1.5 mm to 2.6 mm, preferably 2.3 mm to 2.6 mm from the optical axis. The critical point of the tenth surface (S10) 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 tenth surface (S10) 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.

[0224]

[0225] 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.

[0226] With respect to the optical axis (OA), the eleventh surface (S11) on the object side of the sixth lens (206) may be convex, and the twelfth surface (S12) on the sensor side may be concave. The sixth lens (206) may have a concave meniscus shape on the sensor side. The sixth lens (206) 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. 9.

[0227] The eleventh surface (S11) of the sixth lens (206) may have a critical point from the optical axis to the end of the effective area. When the eleventh surface (S11) has a critical point, it may be located in a range of 20% to 40%, preferably 30% to 35%, of the effective radius from the optical axis. The critical point of the eleventh surface (S11) may be located in a range of 0.5 mm to 1.5 mm, preferably 0.7 mm to 1.3 mm from the optical axis. The critical point of the eleventh surface (S11) 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 eleventh surface (S11) 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.

[0228] The twelfth surface (S12) of the sixth lens (206) may have a critical point from the optical axis to the end of the effective area. When the twelfth surface (S12) has a critical point, it may be located in a range of 15% to 30%, preferably 20% to 25%, of the effective radius from the optical axis. The critical point of the twelfth surface (S12) may be located in a range of 0.5 mm to 1.5 mm, preferably 0.7 mm to 1.3 mm from the optical axis. The critical point of the twelfth surface (S12) 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 twelfth surface (S12) 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.

[0229]

[0230] 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.

[0231] The 13th surface (S13) on the object side of the seventh lens (207) with respect to the optical axis may be convex, and the 14th surface (S14) on the sensor side may be concave. The seventh lens (207) may have a concave meniscus shape on the sensor side. The seventh lens (207) may have a convex meniscus shape on the object side. 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. 9.

[0232] The thirteenth surface (S13) of the seventh lens (207) may have a critical point from the optical axis to the end of the effective area. When the thirteenth surface (S13) has a critical point, it may be located in a range of 20% to 40%, preferably in a range of 30% to 35%, of the effective radius from the optical axis. The critical point of the thirteenth surface (S13) may be located in a range of 1.0 mm to 2.0 mm, preferably in a range of 1.2 mm to 1.8 mm from the optical axis. The critical point of the thirteenth surface (S13) 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 thirteenth surface (S13) 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.

[0233] The fourteenth surface (S14) of the seventh lens (207) may have a critical point from the optical axis to the end of the effective area. When the fourteenth surface (S14) has a critical point, it may be located in a range of 20% to 40%, preferably in a range of 30% to 40%, of the effective radius from the optical axis. The critical point of the fourteenth surface (S14) may be located in a range of 1.0 mm to 2.5 mm, preferably in a range of 1.5 mm to 2.3 mm from the optical axis. The critical point of the fourteenth surface (S14) 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 fourteenth surface (S14) 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.

[0234]

[0235] 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.

[0236] 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. 9.

[0237] 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 10% to 30%, preferably in a range of 20% to 28%, 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).

[0238] 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.

[0239]

[0240] LensSurfaceRadiusThicknessndvdSemiApertureFocal length1S1(Stop)2.84210.97971.546256.33152.06507.3720 S28.48270.0348 1.9644 2S37.53480.24001.677619.23851.9311-17.5410 S44.55210.2743 1.8033 3S57.59480.45971.546256.33151.790029.9620 S613.86780.5227 1.7534 4S757.85570.32581.677619.23851.7750-56.1320 S822.89550.0883 1.9943 5S9-56.42520.66801.546256.33152.260033.5390 S10-13.88800.7536 2.6050 6S1119.59900.67501.619325.95023.0233506.1100 S1220.63100.6185 3.7698 7S135.51940.98621.569737.55104.493191.9700 S145.76910.8378 5.1536 8S15-14.59030.74481.536655.71036.0952-8.9150 S167.24280.1108 6.5277 IRS17Infinity0.2100 7.7133 S18Infinity0.7465 7.7922 Image Infinity-0.0065 8.2596

[0241] 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.

[0242]

[0243] Item ValueItem ValueF8.1600ET10.3470ΣIndex12.7194ET20.3780ΣAbbe326.6830ET30.3260ΣCT4.0884ET 40.2970ΣCG3.9058ET50.5000CA_max12.6229ET60.7330CA_min3.5434ET70.6760CA_Aver6. 1255ET80.6210CT_max0.9797FOV_D88.9924CT_min0.0883LG1_F11.2693CT_Aver0.5110LG2 _F-51.0220EPD4.1300ImgH16.3320BFL1.0608SD8.3200TD8.3200TTL9.2700F-number1.9758

[0244] Table 4 shows the items of the mathematical formulas described above in the optical system (1100) of the embodiment, including the total track length (TTL) (mm), back focal length (BFL), effective focal length (F) (mm), ImgH (mm), effective diameter (CA) (mm), thickness (mm), TTL (mm), the optical axis distance from the first surface (S1) to the sixteenth surface (S16) TD (mm), the optical axis distance from the aperture (Stop) to the sixteenth surface (S16) SD (mm), the sum of refractive indices, the sum of Abbe numbers, the sum of thicknesses (mm), the sum of spacings between adjacent lenses, effective diameter characteristics, the diagonal angle of view (FOV_D) (Degree), the edge thickness (ET), the F number, etc. of the optical system (1100). LG1_F is the composite focal length of the first lens group (LG1) (mm), and LG2_F is the composite focal length of the second lens group (LG2) (mm).

[0245] The center thicknesses of the first to eighth lenses (201 to 208) are represented by CT1 to CT8, the edge thicknesses at the ends of the effective areas of each lens are represented by ET1 to ET8, the center gap between two adjacent lenses is represented by CG1 to CG7, and the edge gaps between the edges of each lens are represented by EG1 to EG7. The BFL (Back focal length) is the optical axis distance from the image sensor (300) 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 (300).

[0246] As shown in Fig. 9, 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, since the aspherical surface having a 30th 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.

[0247] When comparing the absolute values ​​of the curvature radii of each lens, the curvature radii of the ninth surface (S9) of the fifth lens (205) on the optical axis (OA) may be the largest among the lenses, and the curvature radii of the first surface (S1) of the first lens (201) may be the smallest among the lenses. The difference between the maximum curvature radii and the minimum curvature radii may be 30 times or more, for example, in the range of 30 to 40 times. The curvature radii of the object-side surface of the first lens (201) arranged on the object-side of the second lens (202) may be the smallest among the lenses.

[0248] 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 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 (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 smaller than the absolute value of the curvature radius of the twelfth surface (S12). The absolute value of the curvature radius of the thirteenth surface (S13) of the seventh lens (207) may be smaller 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 larger than the absolute value of the curvature radius of the sixteenth surface (S16).

[0249] The ratio of the radius of curvature of each lens can satisfy the following conditions.

[0250] Condition 1: 0.1 < |L1R1 / L1R2| < 0.5

[0251] Condition 2: 1.5 < |L2R1 / L2R2| < 2

[0252] Condition 3: 0.5 < |L3R1 / L3R2| < 1

[0253] Condition 4: 2.5 < |L4R1 / L4R2| < 3

[0254] Condition 5: 4 < |L5R1 / L5R2| < 5

[0255] Condition 6: 0.5 < |L6R1 / L6R2| < 1

[0256] Condition 7: 0.5 < |L7R1 / L7R2| < 1

[0257] Condition 8: 2 < |L8R1 / L782| < 2.5

[0258]

[0259] When describing the central thickness of the lenses based on the optical axis, the central thickness (CT7) of the seventh lens (207) is the largest among the lenses, and the central thickness (CT2) of the second lens (202) 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.

[0260] The central thickness of each lens may satisfy any one of the following conditions:

[0261] Condition 1: CT7 > CT1 > CT2, CT3, CT4, CT5, CT6, CT8

[0262] Condition 2: CT1, CT4, CT3, CT5, CT6, CT7, CT8 > CT2

[0263] Condition 3: CT1, CT5, CT6, CT7, CT8 > CT3 > CT2, CT4

[0264] Condition 4: CT1, CT3, CT5, CT6, CT7, CT8 > CT4 > CT2

[0265] Condition 5: CT1, CT6, CT7, CT8 > CT5 > CT2, CT3, CT4

[0266] Condition 6: CT1, CT7, CT8 > CT6 > CT2, CT3, CT4, CT5

[0267] Condition 7: CT7 > CT1, CT2, CT3, CT4, CT5, CT6, CT8

[0268] Condition 8: CT1, CT7 > CT8 > CT2, CT3, CT4, CT5, CT6

[0269]

[0270] When describing the center spacing (CG) between the lenses, the center spacing (CG6) between the sixth lens (206) and the seventh lens (207) may be the maximum, and the center spacing (CG1) between the first and second lenses (201, 202) 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.

[0271] The center spacing between each lens can satisfy the conditions below.

[0272] Condition 1: CG2, CG3, CG4, CG5, CG6, CG7 > CG1

[0273] Condition 2: CG3, CG4, CG5, CG6, CG7 > CG2 > CG1

[0274] Condition 3: CG4, CG5, CG6, CG7 > CG3 > CG2, CG1

[0275] Condition 4: CG5, CG6, CG7 > CG4 > CG1, CG2, CG3

[0276] Condition 5: CG6, CG7 > CG5 > CG1, CG2, CG3, CG4

[0277] Condition 6: CG6 > CG1, CG2, CG3, CG4, CG5, CG7

[0278] Condition 7: CG6 > CG7 > CG1, CG2, CG3, CG4, CG5

[0279]

[0280] Regarding the effective diameter, the lens with the maximum effective diameter may be the eighth lens (208) closest to the image sensor (300). 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).

[0281] 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).

[0282] The effective diameter of each lens can satisfy any one of the conditions below.

[0283] Condition 1: CA_L5, CA_L6, CA_L7, CA_L8 > CA_L1 > CA_L2, CA_L3, CA_L4

[0284] Condition 2: CA_L1, CA_L4, CA_L5, CA_L6, CA_L7, CA_L8 > CA_L2 > CA_L3

[0285] Condition 3: CA_L1, CA_L2, CA_L4, CA_L5, CA_L6, CA_L7, CA_L8 > CA_L3

[0286] Condition 4: CA_L1, CA_L5, CA_L6, CA_L7, CA_L8 > CA_L4 > CA_L2, CA_L3

[0287] Condition 5: CA_L6, CA_L7, CA_L8 > CA_L5 > CA_L1, CA_L2, CA_L3, CA_L4

[0288] Condition 6: CA_L7, CA_L8 > CA_L6 > CA_L1, CA_L2, CA_L3, CA_L4, CA_L5

[0289] Condition 7: CA_L8 > CA_L7 > CA_L1, CA_L2, CA_L3, CA_L4, CA_L5, CA_L6

[0290] Condition 8: CA_L8 > CA_L1, CA_L2, CA_L3, CA_L4, CA_L5, CA_L6, CA_L7

[0291]

[0292] Regarding the refractive index, the refractive index of the second lens (202) and the fourth lens (204) may be the highest among the lenses and may be greater than 1.5, for example, greater than 1.6. The eighth lens (208) may have the lowest refractive index among the lenses. For example, the refractive index of the eighth lens (208) 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.

[0293] The refractive index of each lens can satisfy any of the conditions below.

[0294] Condition 1: n2, n4, n6, n7 > n1 = n3 = n5 > n8

[0295] Condition 2: n2 = n4 > n1, n3, n5, n6, n7, n8

[0296] Condition 3: n2, n4 > n6 > n1, n3, n5, n7, n8

[0297] Condition 4: n2, n4, n6 > n7 > n1, n3, n5, n8

[0298] Condition 5: n1, n2, n3, n4, n5, n6, n7 > n8

[0299]

[0300] Comparing the Abbe numbers, the Abbe numbers of the first lens (201), the third lens (203), and the fifth lens (205) are the largest among the lenses and may be 50 or more. The Abbe numbers of the second lens (202) and the fourth lens (204) 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.

[0301] The Abbe number of each lens can satisfy any of the conditions below.

[0302] Condition 1: v1 = v3 = v5 > v8, v7, v6, v2, v4

[0303] Condition 2: v1, v3, v5, v6, v7, v8 > v2 = v4

[0304] Condition 3: v1, v3, v5, v7, v8 > v6 > v2, v4

[0305] Condition 4: v1, v3, v5, v8 > v7 > v2, v4, v6

[0306] Condition 5: v1, v3, v5 > v8 > v2, v4, v6, v7

[0307]

[0308] The focal lengths (F2, F4, F8) of the 2nd, 4th, and 8th lenses (202, 204, and 208) may have negative (-) signs. The 2nd, 4th, and 8th lenses (202, 204, and 208) may have negative (-) refractive power. The focal lengths (F1, F3, F5, F6, and F7) of the 1st, 3rd, 5th, 6th, and 7th lenses (201, 203, 205, 206, and 207) may have positive (+) signs. The 1st, 3rd, 5th, 6th, and 7th lenses (201, 203, 205, 206, and 207) may have positive (+) refractive power.

[0309] The first lens (201) and the second lens (202), which are adjacently arranged lenses, can satisfy the following conditions.

[0310] Condition 1: Refractive index of lens with positive refractive power < refractive index of lens with negative refractive power

[0311] Condition 2: Dispersion of a lens with positive refractive power > Dispersion of a lens with negative refractive power

[0312] Here, among the plastic lenses, the first lens (201) has negative refractive power and the second lens (202) has positive refractive power, so that according to conditions 1 and 2, the refractive index of the first lens (201) is greater than the refractive index of the second lens (202), and the dispersion value of the first lens (201) is less than the dispersion value of the second lens (202). The chromatic aberration occurring in the plastic lens can be corrected by the plastic lens. In addition, since the first lens (201) and the second lens (202), which are plastic lenses arranged in succession, satisfy the conditions of a refractive index difference of 0.1 or more and 0.15 or less and an Abbe number difference of 20 or more and 50 or less, the chromatic aberration occurring in the plastic lens can be compensated for by the plastic lens.

[0313] Optical systems suffer from chromatic aberration, and this can be corrected using cemented lenses or two lenses positioned in series. Since lenses made of the same material exhibit the same degree of change in their characteristics with temperature, it is effective to compensate for chromatic aberration between lenses made of the same material, even when the temperature changes. Therefore, in the first embodiment of the present invention, the first lens (201) and the second lens (202) are used to correct chromatic aberration occurring in a plastic lens.

[0314]

[0315] When comparing the focal lengths in absolute values, the focal length of the sixth lens (206) is the largest among the lenses, and may be 500 or more and 600 or less. Among the lenses, the sixth lens (206) made of plastic may have the largest focal length and the smallest refractive power. The focal length of the first lens (201) is the smallest among the lenses, and the absolute value of the focal length of the first lens (201) may be 5 or more and 10 or less. Among the lenses, the first lens (201) made of plastic may have the smallest focal length and the largest refractive power.

[0316] Among the lenses, the lens having the minimum focal length may be the first lens (201). The difference between the maximum focal length and the minimum focal length may be 400 or more or 500 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.

[0317] Among the first to fourth lenses (201-204) arranged adjacent to the object side, the absolute value of the focal length of the first lens (201) may be the smallest. Among the first to fourth lenses (201-204) arranged adjacent to the object side, the refractive power of the first lens (201) may be the largest. Through this, light entering the optical system (1100) may be appropriately refracted to secure optical performance.

[0318] Among the fifth to eighth lenses (205-208) arranged adjacent to the image sensor (300), the absolute value of the focal length of the eighth lens (208) may be the smallest. Among the fifth to eighth lenses (205-208) arranged adjacent to the image sensor (300), the refractive power of the eighth lens (208) may be the largest. Through this, the impact on optical performance when the eighth lens (208) arranged closest to the image sensor (300) shakes can be minimized.

[0319] The absolute value of the focal length of each lens can satisfy any of the conditions below.

[0320] Condition 1: |f2|, |f3|, |f4|, |f5|, |f6|, |f7|, |f8| > |f1|

[0321] Condition 2: |f3|, |f4|, |f5|, |f6|, |f7| > |f2| > |f1|, |f8|

[0322] Condition 3: |f4|, |f5|, |f6|, |f7| > |f3| > |f1|, |f2|, |f8|

[0323] Condition 4: |f6|, |f7| > |f4| > |f1|, |f2|, |f3|, |f5|, |f8|

[0324] Condition 5: |f4|, |f6|, |f7| > |f5| > |f1|, |f2|, |f3|, |f8|

[0325] Condition 6: |f6| > |f1|, |f2|, |f3|, |f4|, |f5|, |f7|, |f8|

[0326] Condition 7: |f6| > |f7| > |f1|, |f2|, |f3|, |f4|, |f5|, |f8|

[0327] Condition 8: |f2|, |f3|, |f4|, |f5|, |f6|, |f7| > |f8| > |f1|

[0328]

[0329] Among the lenses, the first lens (201) positioned closest to the object side may have the greatest refractive power. Among the lenses, the first lens (201) positioned closest to the object side may have the shortest focal length. The lens positioned closest to the image sensor (300) has a problem in that it shakes, resulting in a large change in optical performance. Therefore, by positioning the lens with the greatest refractive power closest to the object side, the stability of performance changes after manufacturing can be secured.

[0330] At least two of the fifth to eighth lenses (205-208) arranged adjacent to the sensor side may have positive refractive power. For example, the fifth to seventh lenses (205, 206, 207) may have positive refractive power, and the eighth lens (208) may have negative refractive power. By designing the refractive power of a plurality of lenses adjacent to the image sensor (300) to be positive refractive power, the MTF resolution of the optical system (1100) can be improved and the amount of curvature can be reduced. The amount of lens curvature refers to a phenomenon in which light rays passing through a lens are bent rather than focused on an ideal imaging plane. The amount of lens curvature can occur because the image sensor is flat. The amount of lens curvature can increase as the curvature of the lens increases.

[0331]

[0332] 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 2 to 3 times the minimum thickness. The thickness (T2) of the second lens (202) may be maximum at the edge and minimum at the center, and the maximum thickness is in the range of 1 to 1.5 times the minimum thickness. The thickness (T3) of the third lens (203) may be maximum at the center and minimum at the edge, and the maximum thickness is in the range of 1 to 1.5 times the minimum thickness. The thickness (T4) of the fourth lens (204) may be maximum at the center and minimum at the edge, and the maximum thickness is in the range of 1 to 1.5 times the minimum thickness. The thickness (T5) of the fifth lens (205) may be maximum at the center and minimum at the edge, and the maximum thickness is in the range of 1 to 1.5 times the minimum thickness. The thickness (T6) of the sixth lens (206) 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 (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 1 to 1.2 times the minimum thickness.

[0333] The thickness of each lens can satisfy any of the conditions below.

[0334] Condition 1: 2.5 < CT1 / ET1 < 3, 0.1 < ET1 / CT1 < 0.5

[0335]

[0336] Condition 2: 0.5 < CT2 / ET2 < 1, 1 < ET2 / CT2 < 1.5

[0337] Condition 3: 1 < CT3 / ET3 < 1.5, 0.5 < ET3 / CT3 < 1

[0338] Condition 4: 1 < CT4 / ET4 < 1.5, 0.5 < ET4 / CT4 < 1

[0339] Condition 5: 1 < CT5 / ET5 < 1.5, 0.5 < ET5 / CT5 < 1

[0340] Condition 6: 0.5 < CT6 / ET6 < 1, 1 < ET6 / CT6 < 1.5

[0341] Condition 7: 1.5 < CT7 / ET7 < 2, 0.3 < ET7 / CT7 < 0.8

[0342] Condition 8: 0.5 < CT8 / ET8 < 1, 1 < ET8 / CT8 < 1.2

[0343] Condition 9: 1 < ΣCT / ΣET < 1.5, 0.5 < ΣET / ΣCT < 1

[0344]

[0345] 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 minimum in the edge and a maximum 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 fourth 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 maximum in the center and a minimum in the edge. The sixth gap (G6) between the sixth and seventh lenses (206, 207) may have a minimum in the center and a maximum in the edge. The seventh gap (G7) between the seventh and eighth lenses (207, 208) may be maximum at the center and minimum at the edge.

[0346]

[0347] The optical systems (1000, 1100) according to the first and second embodiments disclosed above can satisfy at least one or two or more of the mathematical equations described below. Accordingly, the optical systems (1000, 1100) according to the first and second embodiments can have improved optical characteristics. For example, when the optical system (1000, 1100) satisfies at least one mathematical equation, the optical system (1000, 1100) can effectively control aberration characteristics such as chromatic aberration and distortion aberration, and can have good optical performance not only at the center but also at the periphery of the field of view (FOV). In addition, the optical system (1000, 1100) can have improved resolution. In addition, the thickness of the lens on the optical axis (OA) described in the mathematical equations and the spacing between adjacent lenses on the optical axis (OA) can refer to the first and second embodiments disclosed above.

[0348]

[0349] The optical systems (1000, 1100) according to the first and second embodiments disclosed above can satisfy at least one or two or more of the mathematical equations described below. Accordingly, the optical systems (1000, 1100) according to the first and second embodiments can have improved optical characteristics. For example, when the optical system (1000, 1100) satisfies at least one mathematical equation, the optical system (1000, 1100) can effectively control aberration characteristics such as chromatic aberration and distortion aberration, and can have good optical performance not only at the center but also at the periphery of the field of view (FOV). In addition, the optical system (1000, 1100) can have improved resolution. In addition, the thickness of the lens on the optical axis (OA) described in the mathematical equations and the spacing between adjacent lenses on the optical axis (OA) can refer to the first and second embodiments disclosed above.

[0350]

[0351] [Mathematical Formula 1]

[0352] 0.1 < CT5 / CA_L5 < 0.3

[0353] In mathematical expression 1, CT5 is the central thickness of the fifth lens (105, 205), and CA_L5 represents the effective diameter of the fifth lens (105, 205). When mathematical expression 1 is satisfied, the effective diameter of the fifth lens (105, 205) arranged in the central area of ​​the optical system (1000, 1100) can be appropriately set to stably cause light to enter the large image sensor. In the first and second embodiments, mathematical expression 1 can preferably satisfy 0.1 < CT5 / CA_L5 < 0.2.

[0354]

[0355] [Equation 2]

[0356] 0.05 < CT6 / CA_L6 < 0.3

[0357] In mathematical expression 2, CT6 is the central thickness of the sixth lens (106, 206), and CA_L6 represents the effective diameter of the sixth lens (106, 206). When mathematical expression 3 is satisfied, the effective diameter of the sixth lens (106, 206) arranged adjacent to the image sensor is set to be large, so that light can be stably incident on the enlarged image sensor. In the first and second embodiments, mathematical expression 2 can preferably satisfy 0.05 < CT6 / CA_L6 < 0.15.

[0358]

[0359] [Equation 3]

[0360] 0.1 < CT7 / CA_L7 < 0.3

[0361] In mathematical expression 3, CT7 represents the central thickness of the seventh lens (107, 207), and CA_L7 represents the effective diameter of the seventh lens (107, 207). When mathematical expression 3 is satisfied, the effective diameter of the seventh lens (107, 207) arranged adjacent to the image sensor is set to be large, so that light can be stably incident on the enlarged image sensor. In the first and second embodiments, mathematical expression 3 can preferably satisfy 0.1 < CT7 / CA_L7 < 0.2.

[0362]

[0363] [Equation 4]

[0364] 0.01 < CT8 / CA_L8 < 0.08

[0365] In mathematical expression 4, CT8 is the central thickness of the eighth lens (108, 208), and CA_L8 represents the effective diameter of the eighth lens (108, 208). When mathematical expression 4 is satisfied, the effective diameter of the eighth lens (108, 208) arranged closest to the image sensor is set to the largest possible value, thereby stably allowing light to enter the enlarged image sensor. In the first and second embodiments, mathematical expression 4 can preferably satisfy 0.03 < CT8 / CA_L8 < 0.08.

[0366]

[0367] [Equation 5]

[0368] 0.1 < CG1+CG2+CG3+CG4 / CG5+CG6+CG7 < 0.5

[0369] In mathematical expression 5, CGn is the center spacing between the nth lens and the n+1th lens. When mathematical expression 5 is satisfied, the spacing between the lenses arranged adjacent to the image sensor (300) side can be set larger than the spacing between the lenses arranged adjacent to the object side, thereby reducing mutual interference between adjacent lenses. Specifically, since tilting may occur during the lens assembly process on the lens barrel, the spacing between the lenses can be secured to reduce the mutual influence on adjacent lenses. When it is less than the lower limit of mathematical expression 5, there is a problem that the overall TTL increases, and when it is more than the upper limit of mathematical expression 5, there is a problem that mutual interference between the lenses arranged adjacent to the image sensor side increases. In the first and second embodiments, mathematical expression 5 can preferably satisfy 0.3 < CG1 + CG2 + CG3 + CG4 / CG5 + CG6 + CG7 < 0.5.

[0370]

[0371] [Equation 6]

[0372] 0.1 < CT1 / ΣCT < 0.3

[0373] In mathematical expression 6, CT1 is the central thickness of the first lens (101, 201), and ΣCT is the sum of the central thicknesses of the lenses. When mathematical expression 6 is satisfied, the light emitted from the first lens (101, 201), which has a large influence in the entire optical system, sets an optical path for entering the remaining lenses, and the optical system can have good optical performance at the set angle of view and focal length. In the first and second embodiments, mathematical expression 6 can preferably satisfy 0.1 < CT1 / ΣCT < 0.2.

[0374]

[0375] [Equation 7]

[0376] 0.5 < F1 / F < 1

[0377] In mathematical expression 7, F1 is the focal length of the first lens (101, 201), and F is the effective focal length of the optical system. When mathematical expression 7 is satisfied, the optical system (1000, 1100) can have a set angle of view and an appropriate focal length, and a mobile optical system can be provided. In addition, the angle of view can be set to be large in an appropriate TTL range through the first lens (101, 201) having positive (+) refractive power. When it is below the lower limit of mathematical expression 7, the effective diameter or TTL of the lenses may become long, which may cause a problem in that the imaging lens system becomes large. When it is above the upper limit of mathematical expression 7, the influence of the first lens (101, 201) on the entire optical system becomes small, and the refractive power of the lenses needs to be increased, which causes a problem in that it is difficult to correct spherical aberration or distortion aberration. In the first and second embodiments, mathematical expression 7 preferably satisfies 0.8 < F1 / F < 1.

[0378]

[0379] [Equation 8]

[0380] 0.1 < L1R1 / L1R2 < 0.5

[0381] In mathematical expression 8, L1R1 denotes the radius of curvature of the first surface (S1) of the first lens (101, 201), and L1R2 denotes the radius of curvature of the second surface (S2) of the first lens (101, 201). When mathematical expression 8 is satisfied, the radius of curvature of the first lens (101, 201), which has a large influence in the optical system (1000, 1100), can be appropriately set to suppress the deterioration of optical characteristics, and the optical system (1000, 1100) can control the incident light and set the factors affecting the aberration. In the first and second embodiments, mathematical expression 8 can preferably satisfy 0.2 < L1R1 / L1R2 < 0.4.

[0382]

[0383] [Equation 9]

[0384] 3 < CA_L8S2 / CA_L1S1 < 3.5

[0385] In mathematical expression 9, CA_L1S1 denotes the effective diameter of the first surface (S1) of the first lens (101, 201), and CA_L8S2 denotes the effective diameter of the sixteenth surface (S16) of the eighth lens (108, 208). When mathematical expression 9 is satisfied, the deterioration of optical characteristics can be suppressed, and the optical system (1000, 1100) can control the incident light and set the factors affecting aberration. In the first and second embodiments, mathematical expression 9 can preferably satisfy 3 < CA_L8S2 / CA_L1S1 < 3.3.

[0386]

[0387] [Equation 10]

[0388] 3 < CA_L8 / CA_L1 < 3.5

[0389] In mathematical expression 10, CA_L1 denotes the effective diameter of the first lens (101, 201), and CA_L8 denotes the effective diameter of the eighth lens (108, 208). When mathematical expression 10 is satisfied, the deterioration of optical characteristics can be suppressed, and the optical system (1000, 1100) can control the incident light and set the factors affecting aberration. In the first and second embodiments, mathematical expression 10 can preferably satisfy 3 < CA_L8 / CA_L1 < 3.2.

[0390]

[0391] [Equation 11]

[0392] 0.1 < CA_L1 / ImgH < 0.5

[0393] Mathematical expression 11 can set the relationship between the size of the effective diameter (CA_L1) of the first lens (101, 201) and ImgH, the maximum diagonal length of the image sensor. When Mathematical expression 11 is satisfied, TTL suitable for a mobile optical system is satisfied and the set angle of view can be satisfied. When it is less than the lower limit of Mathematical expression 11, there is a problem that the effective diameter of the lens arranged in the optical system (1000, 1100) becomes large, and thus the TTL becomes long. When it exceeds the upper limit of Mathematical expression 11, there is a problem that the angle of view becomes excessively large compared to the angle of view satisfied by the optical system (1000, 1100). In the first and second embodiments, Mathematical expression 11 can preferably satisfy 0.2 < CA_L1 / ImgH < 0.3.

[0394]

[0395] [Equation 12]

[0396] 0.5 < CA_L8 / ImgH < 1

[0397] Mathematical expression 12 can set the relationship between the size of the effective diameter (CA_L8) of the eighth lens (108, 208) and ImgH, the maximum diagonal length of the image sensor. When Mathematical expression 12 is satisfied, the TTL suitable for the mobile optical system is satisfied and the set angle of view can be satisfied. When it is less than the lower limit of Mathematical expression 12, the effective diameter of the lens arranged in the optical system (1000, 1100) becomes large, which causes a problem in that the TTL becomes long. When it exceeds the upper limit of Mathematical expression 12, there is a problem in that the angle of view becomes excessively large compared to the angle of view satisfied by the optical system (1000, 1100). In the first and second embodiments, Mathematical expression 12 can preferably satisfy 0.6 < CA_L8 / ImgH < 0.8.

[0398]

[0399] [Equation 13]

[0400] 0.1 < |LG1_F / LG2_F| < 0.5

[0401] In mathematical expression 13, 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 13 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 the first and second embodiments, mathematical expression 13 can preferably satisfy 0.1 < |LG1_F / LG2_F| < 0.3.

[0402]

[0403] [Equation 14]

[0404] 0.5 < F / TTL < 1

[0405] In mathematical expression 14, F is the effective focal length of the optical system, and TTL (Total track length) means the distance (mm) on the optical axis (OA) from the vertex of the first surface (S1) of the first lens (101, 201) to the upper surface of the image sensor (300). When the optical system (1000, 1100) according to the embodiment satisfies mathematical expression 14, the optical system (1000, 1100) can have an appropriate focal length in the set TTL range, and can form an image while maintaining an appropriate focal length in the mobile optical system. When it is less than the lower limit of mathematical expression 14, the refractive power of the lenses needs to be increased, making it difficult to correct spherical aberration or distortion aberration, and when it exceeds the upper limit of mathematical expression 14, 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 14 can preferably satisfy 0.8 < F / TTL < 0.9.

[0406]

[0407] [Equation 15]

[0408] 0.3 < TTL / ImgH < 0.8

[0409] Mathematical expression 15 TTL (Total track length) means the distance (mm) from the vertex of the first surface (S1) of the first lens (101, 201) to the upper surface of the image sensor (300) on the optical axis (OA), and ImgH means the maximum diagonal length of the image sensor (300). When Mathematical expression 15 is satisfied, the optical system (1000, 1100) can have TTL for application to the mobile image sensor (300), and can provide more improved image quality. When it is less than the lower limit of Mathematical expression 15, 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 15, the effective diameter or TTL of the lenses becomes long, which may cause a problem of the imaging lens system becoming larger. In the first and second embodiments, mathematical expression 15 can preferably satisfy 0.4 < TTL / ImgH < 0.6.

[0410]

[0411] [Equation 16]

[0412] 1.5 < n1 < 1.6

[0413] In mathematical expression 16, n1 is the refractive index of the first lens (101, 201). When mathematical expression 16 is satisfied, the first lens (101, 201) can minimize chromatic aberration by having a high refractive index among plastic lenses. In the first and second embodiments, mathematical expression 16 can preferably satisfy 1.53 < n1 < 1.55.

[0414]

[0415] [Equation 17]

[0416] 2 < CT_Max / CG_Max < 1.5

[0417] In mathematical expression 17, CT_Max is the maximum central thickness among the lenses, and CG_Max is the maximum gap between adjacent lenses. When mathematical expression 17 is satisfied, the optical system can have good optical performance at the focal length at the set angle of view, and can reduce the TTL. In the first and second embodiments, mathematical expression 17 can preferably satisfy 1 < CT_Max / CG_Max < 1.3.

[0418]

[0419] [Equation 18]

[0420] 3 < CA_max / CA_min < 4

[0421] In mathematical expression 18, 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 18 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 18 can preferably satisfy 3.4 < CA_max / CA_min < 3.6.

[0422]

[0423] [Equation 19]

[0424] 0.5 < ΣCG / ΣCT < 1

[0425] In mathematical expression 19, 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 19 is satisfied, the optical system can have good optical performance at the focal length at the set angle of view, and can reduce the TTL. In the first and second embodiments, mathematical expression 19 can preferably satisfy 0.5 < ΣCG / ΣCT < 0.7.

[0426]

[0427] [Equation 20]

[0428] 0.1 < ΣCG / TTL < 0.5

[0429] Mathematical expression 20 can set the relationship between the sum (ΣCG) of the center spacings of adjacent lenses among the first to eighth lenses (101-108, 201-208) and the TTL, which is the distance (mm) from the center of the first surface (S1) to the image surface of the image sensor (300) on the optical axis (OA). To reduce TTL, a lot of light refraction must occur. To refract a lot of light, the power of the lenses must increase, and to increase the power, the lenses become thicker. When it is less than the lower limit of Mathematical expression 20, the sum of the thicknesses of the lenses becomes small and the refractive power becomes weaker, becoming weaker than the desired power. When it is more than the upper limit of Mathematical expression 20, there is a problem that the sum of the thicknesses of the lenses increases excessively, which increases the TTL. In the first and second embodiments, Mathematical expression 20 can preferably satisfy 0.2 < ΣCG / TTL < 0.4.

[0430]

[0431] [Equation 21]

[0432] 0.3 < ΣCT / TTL < 0.8

[0433] Mathematical expression 21 can set the relationship between the sum (ΣCT) of the center thicknesses of the first to eighth lenses (101-108, 201-208) and the TTL, which is the distance (mm) from the center of the first surface (S1) of the first lens (101, 201) to the image surface of the image sensor (300) on the optical axis (OA). To reduce TTL, a lot of light refraction must occur. To refract a lot of light, the power of the lenses must increase, and to increase the power, the lenses become thicker. When it is less than the lower limit of Mathematical expression 21, the sum of the lens thicknesses becomes small and the refractive power becomes weak. When it is more than the upper limit of Mathematical expression 21, there is a problem that the sum of the thicknesses of the lenses increases excessively, which increases the TTL. In the first and second embodiments, Mathematical expression 21 can preferably satisfy 0.4 < ΣCT / TTL < 0.6.

[0434]

[0435] [Equation 22]

[0436] 0.3 < CA_L1 / F < 0.8

[0437] In mathematical expression 22, the size of the effective diameter of the first lens (101, 201) (CA_L1), F is the effective focal length of the optical system. When mathematical expression 22 is satisfied, the TTL suitable for the mobile optical system is satisfied, and the set angle of view can be satisfied. When it is less than the lower limit of mathematical expression 22, the effective diameter of the lens arranged in the optical system (1000, 1100) becomes the largest, which causes a problem in that the TTL becomes long. When it exceeds the upper limit of mathematical expression 22, there is a problem in that the angle of view becomes excessively larger than the angle of view satisfied by the optical system (1000, 1100). In the first and second embodiments, mathematical expression 22 can preferably satisfy 0.3 < CA_L1 / F < 0.5.

[0438]

[0439] [Equation 23]

[0440] 1.5 < F / EPD < 2

[0441] In mathematical expression 23, F represents the effective focal length of the optical system, and EPD represents the diameter of the entrance pupil (effective aperture). When mathematical expression 23 is satisfied, an image with a brightness suitable for shooting can be provided, and a large amount of light can be received by the image sensor. In the first and second embodiments, mathematical expression 23 preferably satisfies 1.8 < F / EPD < 2.

[0442]

[0443] [Equation 24]

[0444] 0.1 < BFL / TTL < 0.3

[0445] In mathematical expression 24, BFL means the optical axis distance from the image sensor (300) to the center of the sensor side of the last lens, and TTL (Total track length) means the distance (mm) on the optical axis (OA) from the vertex of the first surface (S1) of the first lens (101, 201) to the upper surface of the image sensor (300). When mathematical expression 24 is satisfied, the optical system (1000, 1100) can have a set angle of view and an appropriate focal length, and a vehicle optical system can be provided. In addition, the optical system (1000, 1100) can minimize the gap between the last lens and the image sensor (300), and thus can have good optical characteristics at the periphery of the field of view (FOV). In the first and second embodiments, mathematical expression 24 can preferably satisfy 0.1 < BFL / TTL < 0.2.

[0446]

[0447] [Equation 25]

[0448] 85 < FOV_D < 90

[0449] In mathematical expression 25, FOV_H represents the diagonal angle of view (Degree) of the optical system (1000, 1100), and can provide an angle of view suitable for a mobile optical system. In the first and second embodiments, it is preferable to satisfy 87 < FOV_D < 90.

[0450]

[0451] [Equation 26]

[0452] 0.5 < TTL / CA_max < 1

[0453] In mathematical expression 26, TTL (Total track length) means the distance (mm) from the vertex of the first surface (S1) of the first lens (101, 201) to the upper surface of the image sensor (300) on the optical axis (OA), and CA_max represents the maximum effective diameter among the object-side surfaces and the sensor-side surfaces of the lenses. When mathematical expression 26 is satisfied, the optical system can maintain good optical performance and set a size for a slim and compact structure. In the first and second embodiments, mathematical expression 26 can preferably satisfy 0.6 < TTL / CA_max < 0.8.

[0454]

[0455] [Equation 27]

[0456] 9 < TTL < 10

[0457] In mathematical expression 27, TTL (Total track length) means the distance (mm) from the center of the first surface (S1) of the first lens (101, 201) to the upper surface of the image sensor (300) on the optical axis (OA). When mathematical expression 27 is satisfied, a suitable vehicle optical system can be provided. In the first and second embodiments, mathematical expression 27 can preferably satisfy 9 < TTL < 9.5.

[0458]

[0459] [Equation 28]

[0460] 15 < ImgH < 18

[0461] Mathematical expression 28 indicates that ImgH represents the maximum diagonal length of the image sensor (300). Mathematical expression 28 can set the diagonal size of the image sensor (300) and provide an optical system having a mobile sensor size. In the first and second embodiments, Mathematical expression 28 preferably satisfies 16 < ImgH < 17.

[0462]

[0463] [Equation 29]

[0464] 1 < BFL < 1.5

[0465] In mathematical expression 29, BFL is the optical axis distance from the image sensor (300) to the center of the sensor side of the last lens. When mathematical expression 29 is satisfied, the installation space of the filter (400) and the cover glass can be secured, the assembling of the components can be improved through the gap between the image sensor (300) and the last lens, and the joint reliability can be improved. When BFL is less than the range of mathematical expression 29, some of the light traveling to the image sensor cannot be transmitted to the image sensor, which may cause a decrease in resolution. When BFL exceeds the range of mathematical expression 29, stray light may be introduced, which may deteriorate the aberration characteristics of the optical system. In the first and second embodiments, mathematical expression 29 may preferably satisfy 1 < BFL < 1.2.

[0466]

[0467] [Equation 30]

[0468] 8 < F < 8.5

[0469] Mathematical expression 30 can set the overall focal length (F) to suit the mobile optical system. In the first and second embodiments, mathematical expression 30 can preferably satisfy 8 < F < 8.2.

[0470]

[0471] [Equation 31]

[0472]

[0473] In mathematical expression 31, Z can represent Sag, which is the distance from any position on the aspherical surface to the vertex of the aspherical surface along the optical axis. Y can represent the distance from any position on the aspherical surface to the optical axis in the direction perpendicular to the optical axis. c can represent the curvature of the lens, and K can represent the conic constant. In addition, A, B, C, D, E, and F can represent aspheric constants.

[0474]

[0475] The optical system (1000, 1100) according to the first and second embodiments can satisfy at least one or two or more mathematical expressions from mathematical expressions 1 to 31. In this case, the optical system (1000, 1100) can have improved optical characteristics. Specifically, when the optical system (1000, 1100) satisfies at least one or two or more mathematical expressions from mathematical expressions 1 to 31, the optical system (1000, 1100) can have improved resolution and improve aberration and distortion characteristics. In addition, the optical system (1000, 1100) can secure a BFL (Back focal length) for applying a vehicle image sensor (300), can compensate for optical characteristic degradation due to temperature change, and can minimize the gap between the last lens and the image sensor (300), thereby having good optical performance at the center and periphery of the field of view (FOV).

[0476]

[0477] Table 5 shows the result values ​​for the mathematical expressions 1 to 30 described above in the optical system (1000, 1100) of the embodiment. Referring to Table 5, it can be seen that the optical system (1000, 1100) satisfies at least one, two or more, or three or more of the mathematical expressions 1 to 30. In detail, it can be seen that the optical system (1000, 1100) according to the embodiment satisfies all of the mathematical expressions 1 to 30. Accordingly, the optical system (1000, 1100) can have good optical performance and excellent optical characteristics at the center and periphery of the field of view (FOV).

[0478] 수학식제1실시예제2실시예10.1 < CT5 / CA_L5 < 0.30.1360.13720.05 < CT6 / CA_L6 < 0.30.1020.09930.1 < CT7 / CA_L7 < 0.30.1050.10240.01 < CT8 / CA_L8 < 0.080.0570.05950.1 < CG1+CG2+CG3+CG4 / CG5+CG6+CG7 < 0.50.4150.41660.1 < CT1 / ΣCT < 0.30.1920.19370.5 < F1 / F< 10.8970.90380.1 < L1R1 / L1R2 < 0.50.3280.33593 < CA_L8S2 / CA_L1S1 < 3.53.1273.161103 < CA_L8 / CA_L1 < 3.53.1153.133110.1 < CA_L1 / ImgH < 0.50.2460.247120.5 < CA_L8 / ImgH < 10.7670.773130.1 < |LG1_F / LG2_F| < 0.50.2820.221140.5 < F / TTL < 10.8800.880150.3 < TTL / ImgH < 0.80.5680.568161.5 < n1 < 1.61.5461.546171 < CT_Max / CG_Max < 1.51.2711.177183 < CA_max / CA_min < 43.5513.562190.5 < ΣCG / ΣCT < 10.6050.616200.1 < ΣCG / TTL < 0.50.3330.338210.3 < ΣCT / TTL 0.80.5500.548220.3 < CA_L1 / F < 0.80.4930.494231.5 < F / EPD < 21.9801.976240.1 < BFL / TTL < 0.30.1170.1142585 < FOV_D < 9088.70988.992260.5 < TTL / CA_max < 10.7400.734279 < TTL < 109.2709.2702815 < ImgH < 1816.33216.332291 < BFL < 1.51.0881.061308 < F < 8.58.1608.160

[0479] Hereinafter, a camera module according to an embodiment of the present invention will be described with reference to the drawings.

[0480] Figure 15 is an exploded perspective view of a camera device according to an embodiment of the present invention.

[0481] The camera device (10A) may include a camera module.

[0482] The camera device (10A) may include a lens module (20). The lens module (20) may include at least one lens. The lens may be positioned corresponding to the image sensor (300). The lens module (20) may include a lens and a barrel. The lens module (20) may be coupled to a bobbin (210) of a lens driving device (10B). The lens module (20) may be coupled to the bobbin (210) by screw coupling and / or adhesive. The lens module (20) may move integrally with the bobbin (210).

[0483] The camera device (10A) may include a filter (30). The filter (30) may block light of a specific frequency band from passing through the lens module (20) from being incident on the image sensor (300). The filter (30) may be arranged parallel to the xy plane. The filter (30) may be arranged between the lens module (20) and the image sensor (300). The filter (30) may be arranged on the sensor base (40). Alternatively, the filter (30) may be arranged on the base of the lens driving device (10B). The filter (30) may include an infrared filter. The infrared filter may block light in the infrared region from being incident on the image sensor (300).

[0484] The camera device (10A) may include a sensor base (40). The sensor base (40) may be disposed between the lens driving device (10B) and the printed circuit board (50). The sensor base (40) may include a protrusion (41) on which a filter (30) is disposed. An opening may be formed in the portion of the sensor base (40) on which the filter (30) is disposed so that light passing through the filter (30) may be incident on the image sensor (300). The adhesive member (45) may couple or adhere the base (410) of the lens driving device (10B) to the sensor base (40). The adhesive member (45) may additionally serve to prevent foreign substances from entering the interior of the lens driving device (10B). The adhesive member (45) may include at least one of an epoxy, a thermosetting adhesive, and an ultraviolet-curable adhesive.

[0485] The camera device (10A) may include a printed circuit board (50) (PCB, Printed Circuit Board). The printed circuit board (50) may be a substrate or a circuit board. A lens driving device (10B) may be disposed on the printed circuit board (50). A sensor base (40) may be disposed between the printed circuit board (50) and the lens driving device (10B). The printed circuit board (50) may be electrically connected to the lens driving device (10B). An image sensor (300) may be disposed on the printed circuit board (50). Various circuits, elements, control units, etc. may be provided on the printed circuit board (50) to convert an image formed on the image sensor (300) into an electrical signal and transmit it to an external device.

[0486] The camera device (10A) may include an image sensor (300). The image sensor (300) may be configured to form an image by incident light passing through a lens and a filter (30). The image sensor (300) may be mounted on a printed circuit board (50). The image sensor (300) may be electrically connected to the printed circuit board (50). For example, the image sensor (300) may be coupled to the printed circuit board (50) using surface mounting technology (SMT). As another example, the image sensor (300) may be coupled to the printed circuit board (50) using flip chip technology. The image sensor (300) may be arranged such that its optical axis is aligned with that of the lens. That is, the optical axis of the image sensor (300) and the optical axis of the lens may be aligned. The image sensor (300) can convert light irradiated onto the effective image area of ​​the image sensor (300) into an electrical signal. The image sensor (300) can be any one of a CCD (charge coupled device), a MOS (metal oxide semi-conductor), a CPD, and a CID.

[0487] The camera device (10A) may include a motion sensor (70). The motion sensor (70) may be mounted on a printed circuit board (50). The motion sensor (70) may be electrically connected to a control unit (80) through a circuit pattern provided on the printed circuit board (50). The motion sensor (70) may output rotational angular velocity information due to the movement of the camera device (10A). The motion sensor (70) may include a two-axis or three-axis gyro sensor or an angular velocity sensor.

[0488] The camera device (10A) may include a control unit (80). The control unit (80) may be disposed on a printed circuit board (50). The control unit (80) may be electrically connected to the AF coil and the OIS coil of the lens driving device (10B). The control unit (80) may individually control the direction, intensity, amplitude, etc. of the current supplied to the AF coil and the OIS coil. The control unit (80) may control the lens driving device (10B) to perform an autofocus function and / or an image stabilization function. Furthermore, the control unit (80) may perform autofocus feedback control and / or image stabilization feedback control for the lens driving device (10B).

[0489] The camera device (10A) may include a connector (90). The connector (90) may be electrically connected to a printed circuit board (50). The connector (90) may include a port for electrically connecting to an external device.

[0490]

[0491] The features, structures, effects, etc. described in the embodiments above are included in at least one embodiment of the present invention, and are not necessarily limited to just one embodiment. Furthermore, the features, structures, effects, etc. exemplified in each embodiment can be combined or modified in other embodiments by those skilled in the art to which the embodiments pertain. Therefore, the contents related to such combinations and modifications should be construed as falling within the scope of the present invention.

[0492] In addition, although the above description focuses on examples, these are merely examples and do not limit the present invention. Those skilled in the art to which the present invention pertains will appreciate that various modifications and applications not exemplified above are possible without departing from the essential characteristics of the present invention. For example, each component specifically shown in the examples can be modified and implemented. In addition, differences related to such modifications and applications should be interpreted as being included within the scope of the present invention defined in the appended claims.

Claims

1. Including first to eighth lenses arranged along the optical axis, The above fifth lens has positive (+) 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 absolute value of the focal length of the eighth lens among the fifth to eighth lenses is the smallest.

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

3. In paragraph 1, The above first lens has positive (+) refractive power, The above second lens has negative (-) refractive power, An optical system in which the refractive index of the first lens is smaller than the refractive index of the second lens.

4. In paragraph 1, An optical system in which the center spacing between the first lens and the second lens is the smallest among the center spacings of adjacent lenses.

5. 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.

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

7. In any one of paragraphs 1 to 6, An optical system that satisfies the following conditions. <Conditional expression> 9 < TTL < 10 (In the above conditional expression, TTL means the distance on the optical axis from the object side of the first lens to the upper surface of the image sensor.) 8. In any one of paragraphs 1 to 6, An optical system that satisfies the following conditions. <Conditional expression> 0.1 < CG1+CG2+CG3+CG4 / CG5+CG6+CG7 < 0.5 (In the above conditional expression, CGn is the center distance between the nth lens and the n+1th lens.) 9. Including the first to eighth lenses arranged along the optical axis, The above fifth lens has positive (+) 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 absolute value of the focal length of the first lens among the first to eighth lenses is the smallest.

10. In paragraph 9, An optical system in which the refractive index of the first lens is smaller than the refractive index of the second lens.

Images