Optical system and camera device including the same

Abstract

An optical system according to an embodiment of the present disclosure includes first to n-th lenses and an image sensor disposed in order from an object side to an image side, in which the first lens has a positive refractive power and has a minimum effective region diameter or a maximum thickness among the first to n-th lenses; the first to (n-1)-th lenses have positive composite diopters, and the n-th lens has a negative diopter, at least one of an object-side surface and an image-side surface of the n-th lens including a critical point with an inclination angle of 0, a sag value of a critical point of an X-axis, a sag value of a critical point of a Y-axis, and a sag value of a critical point in one direction between the X-axis and the Y-axis of at least one of the object-side surface and the image-side surface of the n-th lens are different from each other, the X-axis being perpendicular to the optical axis and parallel to one side of the image sensor, the Y-axis being perpendicular to the optical axis and the X-axis, and the sag value of a critical point in one direction between the X-axis and the Y-axis being perpendicular to the optical axis and parallel to one side of the image sensor. And n is an integer greater than or equal to 6.

Description

Technical Field

[0001] Embodiments of the present disclosure relate to an optical system and a camera apparatus including the optical system. Background Art

[0002] As the performance of camera devices built into mobile terminals develops, the demand for higher resolution in camera devices in mobile terminals is also growing. In order to improve the performance of camera devices, high-performance optical systems and image sensors are required. However, due to the narrow space in mobile terminals, it is not easy to achieve high performance of optical systems and image sensors.

[0003] Specifically, the demand for miniaturization of camera devices has further increased. As camera devices become smaller, the amount of light reaching an image sensor through an optical system may decrease. Therefore, the F number that determines the brightness of an image may increase, and the amount of light reaching an outer edge area of ​​the image sensor may decrease compared to the amount of light reaching a central area of ​​the image sensor. Summary of the invention

[0004] Technical issues

[0005] The technical purpose to be achieved by the present disclosure is to obtain a camera module having a small F number, a large field of view, and a high relative illumination and being implemented in a small size.

[0006] The purpose to be achieved in the embodiments is not limited thereto, and it can be said that purposes or effects that can be understood from solutions to the problems described below or specific contents for achieving the present disclosure are also included.

[0007] Technical Solution

[0008] An optical system according to an embodiment of the present disclosure includes first to nth lenses arranged in sequence from an object side to an image side and an image sensor, wherein the first lens has positive refractive power and is a lens having a smallest effective area diameter or a maximum thickness among the first to nth lenses, the first to n-1th lenses have positive compound refractive power, the nth lens has negative refractive power, at least one of the object side surface and the image side surface of the nth lens includes a critical point with an inclination angle of 0, a sag value of the critical point of the X-axis, a sag value of the critical point of the Y-axis, and a sag value of the critical point in a direction between the X-axis and the Y-axis of at least one of the object side surface and the image side surface of the nth lens are different from each other, the X-axis is perpendicular to the optical axis and parallel to one side of the image sensor, the Y-axis is perpendicular to the optical axis and the X-axis, and n is an integer greater than or equal to 6.

[0009] According to another embodiment of the present disclosure, an optical system includes first to nth lenses arranged in sequence from an object side to an image side and an image sensor, wherein the first lens has positive refractive power, a ratio of a diameter of an effective area of ​​the first lens to a diagonal length of the image sensor is greater than 0.15 and less than 0.35, the first to n-1th lenses have positive compound refractive power, the nth lens has negative refractive power, at least one of an object side surface and an image side surface of the nth lens includes a critical point with an inclination angle of 0, a sag value of a critical point of an X-axis, a sag value of a critical point of a Y-axis, and a sag value of a critical point in a direction between the X-axis and the Y-axis of at least one of the object side surface and the image side surface of the nth lens are different from each other, the X-axis is perpendicular to the optical axis and parallel to one side of the image sensor, the Y-axis is perpendicular to the optical axis and the X-axis, and n is an integer greater than or equal to 6.

[0010] Among the first to n-th lenses, the center thickness of the first lens on the optical axis may be the largest, and among the first to n-th lenses, the thickness at the end of the effective area of ​​the first lens may be only smaller than the thickness at the end of the effective area of ​​the n-th lens.

[0011] When the center thickness of the first lens on the optical axis may be CT1, the distance from the object side surface of the first lens to the image sensor may be TTL, and the sum of the center thicknesses of the first lens to the nth lens on the optical axis may be CT_1n, CT1 / TTL may be greater than 0.1 and less than 0.2, and CT1 / CT_1n may be greater than 0.2 and less than 0.35.

[0012] n can be 6.

[0013] The deviation between the sag value of the critical point of the X-axis and the sag value of the critical point in the direction 45 degrees with respect to the X-axis of at least one of the object-side surface and the image-side surface of the nth lens may be greater than the deviation between the sag value of the critical point of the X-axis and the sag value of the critical point of the Y-axis of at least one of the object-side surface and the image-side surface of the nth lens.

[0014] Among the absolute value of the sag value of the critical point of the X-axis, the absolute value of the sag value of the critical point of the Y-axis, and the absolute value of the sag value of the critical point in the direction 45 degrees to the X-axis of at least one of the object-side surface and the image-side surface of the nth lens, the absolute value of the sag value of the critical point in the direction 45 degrees to the X-axis can be the smallest.

[0015] From a point that is 50% of the effective area of ​​at least one of the object side surface and the image side surface of the nth lens to the end of the effective area, the absolute value of the deviation between at least two of the sag value of the X-axis, the sag value of the Y-axis, the sag value in the direction of 45 degrees to the X-axis, and the sag value in the diagonal direction of the image sensor can be greater than 2μm.

[0016] Both the object-side surface and the image-side surface of the sixth lens may have circular asymmetric shapes.

[0017] The second lens may have negative refractive power, the third lens may have positive refractive power, the fourth lens may have negative refractive power, and the fifth lens may have positive refractive power.

[0018] An aperture may be arranged in front of the object-side surface of the first lens, and when the aperture is closed, the shortest distance between the aperture and the object-side surface of the first lens may be less than 0.2 mm.

[0019] A diameter of an effective area of ​​the image-side surface of the sixth lens may be 1.2 times or more the diameter of an effective area of ​​the object-side surface of the first lens.

[0020] An object-side surface or an image-side surface of at least one of the first to n-1th lenses may include a critical point.

[0021] The object-side surface and the image-side surface of the fourth lens each include a critical point, and a distance between the optical axis and the critical point of the object-side surface of the fourth lens may be 0.95 to 1.05 times a distance between the optical axis and the critical point of the image-side surface of the fourth lens.

[0022] Among the center thicknesses of the first to n-th lenses, the center thickness of the second lens or the center thickness of the fourth lens may be the smallest.

[0023] The F number may be 2.3 or less, the field of view (FOV) may be 85 degrees or more, and the relative illumination (RI) may be 30% or more.

[0024] Beneficial Effects

[0025] According to the embodiments of the present disclosure, it is possible to obtain a camera apparatus having a small F number, a large field of view (FOV), and a high relative illumination (RI) while being implemented in a small size.

[0026] According to the embodiments of the present disclosure, a camera apparatus having an F number of 2.3 or less, a FOV of 85 degrees or more, and an RI in 1 field of 30% or more while being implemented in a small size can be obtained.

[0027] According to an embodiment of the present disclosure, a camera device that provides an image with a high RI while minimizing the size of the head exposed to the outside can be obtained. That is, in order to minimize the size of the head exposed to the outside, a camera device that provides an image with a high RI around the sensor while designing the diameter of the first lens (that is, the lens disposed closest to the object side) to be smaller can be obtained.

[0028] According to the embodiments of the present disclosure, an optical system and a camera device having excellent manufacturability can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figures 1 to 3 An optical system according to one embodiment of the present disclosure is shown.

[0030] Figure 4 The relationship between the first lens and the aperture in the optical system according to the embodiment of the present disclosure is shown.

[0031] Figure 5 and Figure 6 It is a view used to describe relative illumination.

[0032] Figure 7 1 is design data showing the distance between lens surfaces according to the distance from the optical axis in the Y direction in the optical system according to the embodiment of the present disclosure.

[0033] Figure 8 1 is design data showing sag values ​​of lens surfaces according to distances from the optical axis in the Y direction in the first to fifth lenses of the optical system according to an embodiment of the present disclosure.

[0034] Fig. 9 1 is design data showing sag values ​​of a lens surface according to distances from the optical axis in the X direction, the Y direction, the diagonal direction, and the 45-degree direction in the sixth lens of the optical system according to an embodiment of the present disclosure.

[0035] Fig.10 1 is design data showing the inclination angle of the lens surface according to the distance from the optical axis in the Y direction in the optical system according to the embodiment of the present disclosure.

[0036] Fig.11 An image-side surface of a sixth lens and an image sensor of an optical system according to an embodiment of the present disclosure are shown.

[0037] Fig.12 The modulation transfer function (MTF) of an optical system used according to one embodiment of the present disclosure is shown.

[0038] Fig.13 A distortion grid using an optical system according to one embodiment of the present disclosure is shown.

[0039] Fig.14 is a cross-sectional view of an optical system according to a comparative example.

[0040] Fig.15 is a view showing a portion of a mobile terminal to which a camera device according to one embodiment of the present disclosure is applied. DETAILED DESCRIPTION

[0041] Hereinafter, exemplary embodiments according to the present disclosure will be described in detail with reference to the accompanying drawings.

[0042] However, the technical spirit of the present disclosure is not limited to some embodiments to be described, but can be implemented in various different forms, and one or more components between the embodiments can be selectively combined and replaced within the technical spirit of the present disclosure.

[0043] In addition, unless explicitly specifically defined and described otherwise, the terms (including technical terms and scientific terms) used in the embodiments of the present disclosure may be interpreted as meanings that can be generally understood by those skilled in the art, and the meanings of commonly used terms (for example, terms defined in dictionaries) may be understood in consideration of the contextual meanings in the relevant technology.

[0044] Furthermore, the terms used in the embodiments of the present disclosure are provided not to limit the present disclosure but to describe the embodiments.

[0045] In this specification, unless otherwise specified in a phrase, a singular form may also include a plural form, and when disclosed as at least one (or more than one) of "A, B, and C", it may include more than one combination of all possible combinations of A, B, and C.

[0046] In addition, terms such as first, second, A, B, (a), (b), etc. may be used to describe components of embodiments of the present disclosure.

[0047] These terms are provided only to distinguish one component from another, and the nature, sequence, order, etc. of the elements are not limited by these terms.

[0048] Furthermore, when a specific component is disclosed as being “connected,” “combined” or “linked” to other components, this may include not only a case where the component is directly connected, combined or linked to the other components, but also a case where the component is connected, combined or linked to the other components via another component located between the component and the other components.

[0049] Furthermore, when one component is disclosed as being formed "on or under" another component, the term "on or under" includes both the case where the two components are in direct contact with each other and the case where another component is at least (indirectly) disposed between the two components. Furthermore, when the term "on or under" is expressed, not only the meaning based on the upward direction of one component but also the meaning based on the downward direction of the one component may be included.

[0050] Figures 1 to 3 An optical system according to one embodiment of the present disclosure is shown. Figure 1 is the cross-sectional view in the YZ direction, Figure 2 is the cross-sectional view in the XZ direction, Figure 3 : is a cross-sectional view in the DZ direction. Here, the Z direction is the direction of the optical axis, the X direction is a direction perpendicular to the direction of the optical axis and parallel to one side of the image sensor, the Y direction is a direction perpendicular to the direction of the optical axis and the X direction, and the D direction is a direction perpendicular to the direction of the optical axis and between the X direction and the Y direction. In the following, an example in which the ratio of the X-axis length to the Y-axis length of the image sensor is 4 to 3 is described, but it is not limited thereto.

[0051] Reference Figure 1 According to an embodiment of the present disclosure, the optical system 100 includes a first lens 110, a second lens 120, a third lens 130, a fourth lens 140, a fifth lens 150, a sixth lens 160, a filter 170 and an image sensor 180, which are arranged in sequence from the object side to the image side.

[0052] Although not shown, a right angle prism may be further disposed in front of the first lens 110 .

[0053] At least one of the first lens 110, the second lens 120, the third lens 130, the fourth lens 140, the fifth lens 150, and the sixth lens 160 may include an effective area and an ineffective area. The effective area may be an area through which light incident on the lens passes, that is, an area through which the incident light is refracted to achieve optical characteristics. In the present specification, the effective diameter may refer to the diameter of the effective area through which the effective light is incident on each surface of each lens. In the present specification, the value of the effective diameter may have a certain error range. For example, a range of ±0.4 mm for the value of the effective diameter proposed in the present specification may be considered as an effective area, and a range of ±0.4 mm for the value of the effective diameter proposed in the present specification may be interpreted as an effective diameter. The ineffective area is set at the outer edge of the effective area and may be an area where no light is incident, that is, an area that is not related to optical characteristics. The ineffective area may be an area fixed to a lens barrel that accommodates lenses, etc.

[0054] According to an embodiment of the present disclosure, the filter 170 and the image sensor 180 may be sequentially arranged behind the sixth lens 160. In this case, the filter 170 may be an infrared (IR) filter. Thus, the filter 170 may block near-infrared light (e.g., light having a wavelength of 700nm to 1100nm) in the light incident on the camera device. Alternatively, the filter 170 may be a filter that transmits IR, rather than a filter that blocks IR. In addition, the image sensor 180 may be connected to a printed circuit board.

[0055] According to an embodiment of the present disclosure, a first lens 110, a second lens 120, a third lens 130, a fourth lens 140, a fifth lens 150, and a sixth lens 160 may be sequentially arranged along the optical axis. According to an embodiment of the present disclosure, the first lens 110, the second lens 120, the third lens 130, the fourth lens 140, and the fifth lens 150 may be circular symmetric lenses, and the sixth lens 160 may be a circular asymmetric lens. The first lens 110, the second lens 120, the third lens 130, the fourth lens 140, the fifth lens 150, and the sixth lens 160 may each be made of plastic or glass.

[0056] The first lens 110 has positive refractive power and includes an object-side surface 112 and an image-side surface 114, the object-side surface 112 of the first lens 110 may be convex toward the object side, and the image-side surface 114 may be concave toward the image side. Here, the case where the surface of the lens is convex may refer to that the surface of the lens in the region corresponding to the optical axis has a convex shape, and the case where the surface of the lens is concave may refer to that the surface of the lens in the region corresponding to the optical axis has a concave shape. Here, the region corresponding to the optical axis may refer to the optical axis region or the paraxial region. In addition, the case where the surface of the lens is convex toward the object side may refer to that the surface of the lens is concave toward the image side, and the case where the surface of the lens is convex toward the image side may refer to that the surface of the lens is concave toward the object side.

[0057] The second lens 120 has negative refractive power and includes an object-side surface 122 and an image-side surface 124 , the object-side surface 122 of the second lens 120 may be concave toward the object side, and the image-side surface 124 may be concave toward the image side.

[0058] The third lens 130 has positive refractive power and includes an object-side surface 132 and an image-side surface 134 , the object-side surface 132 of the third lens 130 may be convex toward the object side, and the image-side surface 134 may be convex toward the image side.

[0059] The fourth lens 140 has negative refractive power and includes an object-side surface 142 and an image-side surface 144 , the object-side surface 142 of the fourth lens 140 may be convex toward the object side, and the image-side surface 144 may be concave toward the image side.

[0060] The fifth lens 150 has positive refractive power and includes an object-side surface 152 which is convex toward the object side and an image-side surface 154 which is convex toward the image side.

[0061] The sixth lens 160 has negative refractive power and includes an object-side surface 162 and an image-side surface 164 , the object-side surface 162 of the sixth lens 160 may be concave toward the object side, and the image-side surface 164 may be concave toward the image side.

[0062] As in an embodiment of the present disclosure, when the first lens 110 has positive refractive power, the second lens 120 has negative refractive power, the third lens 130 has positive refractive power, the fourth lens 140 has negative refractive power, the fifth lens 150 has positive refractive power, and the sixth lens 160 has negative refractive power, chromatic aberration can be corrected during the process of repeatedly collecting and transmitting light, and light can reach the outer edge of the image sensor uniformly.

[0063] Figure 4 The relationship between the first lens and the aperture in the optical system according to the embodiment of the present disclosure is shown.

[0064] Reference Figure 4 , the aperture ST is disposed closer to the object side than the first lens 110. The aperture ST may adjust the amount of light incident on the optical system 100. Therefore, the optical system 100 according to an embodiment of the present disclosure includes an aperture ST, a first lens 110, a second lens 120, a third lens 130, a fourth lens 140, a fifth lens 150, and a sixth lens 160, which are sequentially disposed from the object side to the image side. According to an embodiment of the present disclosure, the aperture ST is disposed closer to the object side than the object side surface 112 of the first lens 110. In a state where the aperture ST is closed, the aperture ST may be disposed in front of an area corresponding to the optical axis of the object side surface 112 of the first lens 110. For example, in a state where the aperture ST is closed, the aperture ST may be disposed in front of a region corresponding to the optical axis OA of the object-side surface 112 of the first lens 110, and the distance from the region corresponding to the optical axis OA of the object-side surface 112 of the first lens 110 is 0.2 mm or less, preferably 0.1 mm or less, more preferably 0.05 mm or less, and even more preferably 0.01 mm or less. In the case where the aperture ST is not a drivable aperture, the shortest distance between the position where the aperture is disposed and the object-side surface 112 of the first lens 110 may be 0.2 mm or less.

[0065] According to an embodiment of the present disclosure, the entrance pupil diameter (EPD) of the optical system 100 may be equal to the effective diameter (EDD) of the object-side surface 112 of the first lens 110. L1S1 The EPD of the optical system 100 may be the effective diameter (ED) of the object-side surface 112 of the first lens 110. L1S1 ), preferably 0.95 to 1.05 times, and more preferably 0.97 to 1.03 times. Therefore, since the area of ​​the object-side surface 112 of the first lens 110 exposed to the outside can be minimized, the head size of the optical system 100 can be minimized.

[0066] Refer again Figure 1, among the first lens 110, the second lens 120, the third lens 130, the fourth lens 140, the fifth lens 150 and the sixth lens 160, the object-side surface 112 of the first lens 110 has the smallest effective diameter. For example, the effective diameter (ED L1S1 ) can be 1.422mm to 1.738mm, preferably 1.501mm to 1.659mm, and more preferably 1.533mm to 1.627mm.

[0067] According to an embodiment of the present disclosure, the effective diameter of the object-side surface 112 of the first lens 110 may be smaller than the length in the diagonal direction of the image sensor 180. For example, the effective diameter (ED L1S1 ) and the length in the diagonal direction of the image sensor 180 (2*H imageD ) may be 0.15 to 0.35, preferably 0.2 to 0.3, and more preferably 0.22 to 0.26. L1S1 ) and the length in the diagonal direction of the image sensor 180 (2*H imageD ) satisfies the above conditions, a design that minimizes the head size of the optical system exposed to the outside can be performed within the range in which the first lens 110 can be manufactured. Since it may be difficult to manufacture the first lens when the above ratio is below the lower limit, and the object-side surface of the first lens may be exposed to the outside when the above ratio exceeds the upper limit, it may be difficult to apply the design to an application that minimizes the head size.

[0068] According to an embodiment of the present disclosure, the effective diameter of the object-side surface 112 of the first lens 110 may be 0.3 to 0.4 times, preferably 0.325 to 0.385 times, and more preferably 0.35 to 0.7 times, the TTL of the optical system. L1S1 ) and TTL satisfy the above conditions, a design that minimizes the head size of the optical system exposed to the outside can be performed within the range in which the first lens 110 can be manufactured. Since it may be difficult to manufacture the first lens when the value is below the lower limit, and the object-side surface of the first lens may be exposed to the outside when the value exceeds the upper limit, it may be difficult to apply the design to an application that minimizes the head size.

[0069] When the aperture ST is disposed in front of the object-side surface 112 of the first lens 110, since the amount of light incident on the first lens 110 can be maximized while minimizing the area of ​​the optical system 100 exposed to the outside, the optical system 100 can be implemented in a compact size. For example, a camera device including the optical system 100 according to an embodiment of the present disclosure can be implemented so as not to be exposed to the naked eye of a user. For example, a camera device including the optical system 100 according to an embodiment of the present disclosure can be implemented so as to be disposed in front of a mobile terminal. For example, a camera device including the optical system 100 according to an embodiment of the present disclosure can be implemented so as to be disposed below a display.

[0070] In addition, as the effective diameter of the first lens 110 becomes smaller, the size of the head exposed to the outside can be minimized. However, as the effective diameter of the first lens 110 becomes smaller, it may be difficult to manufacture the first lens 110, and the amount of light incident on the optical system 100 may be insufficient. Therefore, when designing an optical system including the first lens 110, while making it easy to manufacture the first lens, it is necessary to consider the condition of brightening the image by reducing the F number and improving the ratio of the amount of light incident on the outer edge of the image sensor to the amount of light incident on the center of the image sensor (that is, relative illumination (RI)).

[0071] Here, the center of the image sensor refers to an area close to the 0 field of the image sensor, and the outer edge of the image sensor refers to an area close to the 1 field of the image sensor.

[0072] Figure 5 and Figure 6 It is a view used to describe relative illumination.

[0073] Reference Figure 5 , it can be seen that the area reaching the image sensor changes depending on the incident angle of light incident from the object side. That is, the image sensor is divided into a 0 field area which is the center of the image sensor and a 1 field area which is the position farthest from the center of the image sensor, and it can be seen that when the incident angle of light is large, the light is closer to the 1 field area (outer edge) of the image sensor, and when the incident angle of light is small, the light is closer to the 0 field area (center).

[0074] Reference Figure 6 , assuming that the first light ray A is a light ray parallel to the field of view (FOV) of the optical system 100. The first light ray A may be incident on the object-side surface 112 of the first lens 110 and form an angle α with the optical axis OA of the first lens 110. In this case, an angle formed by the first light ray A and a normal (line c) at a point P where the first light ray A and the object-side surface 112 of the first lens 110 contact each other may be defined as an incident angle θ.

[0075] According to an embodiment of the present disclosure, the lenses forming the optical system 100 are designed to reduce the F number and improve the RI.

[0076] Tables 1 and 2 below show optical properties of lenses included in the optical system according to an embodiment of the present disclosure, Table 3 shows Qcon coefficients of the first to fifth lenses included in the optical system according to an embodiment of the present disclosure, and Table 4 shows the Zemike coefficient of the sixth lens included in the optical system according to an embodiment of the present disclosure.

[0077] [Table 1]

[0078]

[0079] [Table 2]

[0080]

[0081] [Table 3]

[0082]

[0083] [Table 4]

[0084]

[0085]

[0086] In Table 1, the thickness (mm) indicates the distance from each lens surface to the next lens surface. For example, the disclosed thickness of the aperture ST indicates the distance from the aperture ST to the object-side surface 112 of the first lens 110. Here, when the aperture ST is a drivable aperture, the distance from the aperture ST to the object-side surface 112 of the first lens 110 may refer to the distance from the aperture ST to the object-side surface 112 of the first lens 110 in a state where the aperture ST is closed. The disclosed thickness of the object-side surface 112 of the first lens 110 indicates the distance from the object-side surface 112 of the first lens 110 to the image-side surface 114. In Table 1, the thickness (mm) may refer to the distance from the optical axis. Specifically, the disclosed thickness of the object-side surface 112 of the first lens 110 may indicate the distance between the center of curvature of the object-side surface 112 and the center of curvature of the image-side surface 114 of the first lens 110. The disclosed thickness of the image-side surface 114 of the first lens 110 represents the distance from the image-side surface 114 of the first lens 110 to the object-side surface 122 of the second lens 120. Specifically, the disclosed thickness of the image-side surface 114 of the first lens 110 represents the distance between the center of curvature of the image-side surface 114 of the first lens 110 and the center of curvature of the object-side surface 122 of the second lens 120.

[0087] In Table 1 or Table 2, the center thickness CT may refer to the thickness of each lens on the optical axis. For example, the center thickness of the first lens 110 may represent the distance between the center of curvature of the object-side surface 112 and the center of curvature of the image-side surface 114 in the first lens 110. The air gap may refer to the distance between adjacent lenses on the optical axis. For example, the air gap of the first lens 110 may represent the distance between the center of curvature of the image-side surface 114 of the first lens 110 and the center of curvature of the object-side surface 122 of the second lens 120.

[0088] The thickness of the object-side surface of the first to fifth lenses (which are circularly symmetric lenses) disclosed in Table 1 may match the center thickness of the first to fifth lenses in Table 2, and the thickness of the image-side surface of the first to fourth lenses (which are circularly symmetric lenses) disclosed in Table 1 may match the air gap of the first to fourth lenses in Table 2. However, since the object-side surface 162 and the image-side surface 164 of the sixth lens 160 have circular asymmetric shapes, there may be an offset. Therefore, the thickness of the image-side surface 154 of the fifth lens 150 disclosed in Table 1 (that is, the distance between the image-side surface 154 of the fifth lens 150 and the object-side surface 162 of the sixth lens 160) may not match the air gap of the fifth lens 150 disclosed in Table 2. Similarly, the thickness of the object-side surface 162 of the sixth lens 160 disclosed in Table 1 may not match the center thickness of the sixth lens 160 disclosed in Table 2.

[0089] In the optical system 100 according to an embodiment of the present disclosure, the first lens 110, the second lens 120, the third lens 130, the fourth lens 140 and the fifth lens 150 may be referred to as the first lens group G1, and the sixth lens 160 may be referred to as the second lens group G2. The lenses included in the first lens group G1 have a circular symmetrical shape, and the lenses included in the second lens group G2 have a circular asymmetrical shape. The compound refractive power of the first lens group G1 is positive, and the compound refractive power of the second lens group G2 is negative. Therefore, the first lens group G1 can be used to collect incident light and correct chromatic aberration, and the second lens group G2 can be used to disperse the incident light so that the incident light reaches the outer edge pixels of the image sensor uniformly. In an embodiment of the present disclosure, the second lens group includes a sixth lens 160 having a circular asymmetrical shape. When the sixth lens 160 has a circular asymmetrical shape, although the sixth lens 160 is a single lens, the effect of a plurality of lenses overlapping each other can also be obtained.

[0090] According to an embodiment of the present disclosure, among the first to sixth lenses, the first lens 110 may have the largest center thickness. According to an embodiment of the present disclosure, the sum of the center thickness CT2 of the second lens 120 and the center thickness CT3 of the third lens 130 may be less than the center thickness CT1 of the first lens 110. According to an embodiment of the present disclosure, the ratio of the center thickness CT1 of the first lens 110 to the center thickness CT2 of the second lens 120 may be greater than 2 times, or more preferably greater than 3 times. According to an embodiment of the present disclosure, the ratio of the center thickness CT1 of the first lens 110 to the center thickness CT4 of the fourth lens 140 may be greater than 1 times, preferably greater than 2 times, or more preferably greater than 3 times. According to an embodiment of the present disclosure, the sum of the center thickness CT2 of the second lens 120 and the center thickness CT4 of the fourth lens 140 may be less than the center thickness CT1 of the first lens 110. According to an embodiment of the present disclosure, the sum of the center thickness CT2 of the second lens 120 and the center thickness CT6 of the sixth lens 160 may be less than the center thickness CT1 of the first lens 110. According to an embodiment of the present disclosure, the sum of the center thickness CT4 of the fourth lens 140 and the center thickness CT6 of the sixth lens 160 may be smaller than the center thickness CT1 of the first lens 110. Therefore, when the center thickness CT1 of the first lens 110 having the smallest effective diameter among the first to sixth lenses is the largest among the first to sixth lenses, while improving the manufacturability of the first lens 110, even when the effective diameter of the object-side surface 112 of the first lens 110 is sufficiently small, light may be collected by the first lens without distortion, and the first lens may be used to collect light and correct chromatic aberration.

[0091] According to an embodiment of the present disclosure, the center thickness CT1 of the first lens 110 may be greater than 0.2 times and less than 0.35 times, preferably greater than 0.25 times and less than 0.33 times, and more preferably greater than 0.27 times and less than 0.31 times, of the sum of the center thicknesses CT_16 of the first lens 110 to the sixth lens 160. According to an embodiment of the present disclosure, the center thickness CT1 of the first lens 110 may be greater than 0.55 mm, preferably greater than 0.6 mm, and more preferably greater than 0.63 mm. Therefore, while improving the manufacturability of the first lens 110, even when the effective diameter of the object-side surface 112 of the first lens 110 is sufficiently small, light can be collected by the first lens without distortion, and the first lens can be used to collect light and correct chromatic aberration.

[0092] According to an embodiment of the present disclosure, the center thickness CT1 of the first lens 110 may be 0.1 times or more and 0.2 times or less, preferably 0.12 times or more and 0.18 times or less, more preferably 0.13 times or more and 0.17 times or less, and even more preferably 0.14 times or more and 0.16 times or less of TTL, where TTL is the distance from the object-side surface 112 of the first lens 110 to the image sensor 180. Therefore, while improving the manufacturability of the first lens 110, even when the effective diameter of the object-side surface 112 of the first lens 110 is sufficiently small, light can be collected by the first lens without distortion, and the first lens can be used to collect light and correct chromatic aberration.

[0093] When the center thickness CT1 of the first lens 110 satisfies the above conditions, a small head lens including a barrel having a diameter of 2.15 mm or less can be manufactured. That is, according to an embodiment of the present disclosure, in order to minimize the head size of the optical system 100, the diameter of the effective area of ​​the first lens 110 can be implemented as the minimum diameter among the diameters of the effective areas of the first lens 110 to the sixth lens 160. For example, according to an embodiment of the present disclosure, the diameter of the effective area of ​​the first lens 110 can be designed to be 1.58 mm. When the center thickness CT1 of the first lens 110 satisfies the above conditions, the first lens 110 that satisfies the design of the diameter of the effective area of ​​the first lens 110 can be manufactured.

[0094] The distance between the first lens group G1 and the second lens group G2 of the present disclosure (that is, the distance T56 between the image-side surface 154 of the fifth lens 150 and the object-side surface 162 of the sixth lens 160) may be greater than the distances between adjacent lenses in the first lens group G1, for example, at least one of the distance T12 between the image-side surface 114 of the first lens 110 and the object-side surface 122 of the second lens 120, the distance T23 between the image-side surface 124 of the second lens 120 and the object-side surface 132 of the third lens 130, the distance T34 between the image-side surface 134 of the third lens 130 and the object-side surface 142 of the fourth lens 140, and the distance T45 between the image-side surface 144 of the fourth lens 140 and the object-side surface 152 of the fifth lens 150. The distance between the first lens group G1 and the second lens group G2 of the present disclosure (that is, the distance T56 between the image-side surface 154 of the fifth lens 150 and the object-side surface 162 of the sixth lens 160) may be greater than the distance T12 between the image-side surface 114 of the first lens 110 and the object-side surface 122 of the second lens 120, and may be greater than the distance T23 between the image-side surface 124 of the second lens 120 and the object-side surface 132 of the third lens 130. The distance between the first lens group G1 and the second lens group G2 of the present disclosure (that is, the distance T56 between the image-side surface 154 of the fifth lens 150 and the object-side surface 162 of the sixth lens 160) may be greater than the distance T34 between the image-side surface 134 of the third lens 130 and the object-side surface 142 of the fourth lens 140, or may be 0.95 to 1.1 times, preferably 0.97 to 1.07 times, and more preferably 0.99 to 1.05 times, of the distance T34 between the image-side surface 134 of the third lens 130 and the object-side surface 142 of the fourth lens 140. The distance between the first lens group G1 and the second lens group G2 of the present disclosure (that is, the distance T56 between the image-side surface 154 of the fifth lens 150 and the object-side surface 162 of the sixth lens 160) may be greater than the distance T45 between the image-side surface 144 of the fourth lens 140 and the object-side surface 152 of the fifth lens 150, or may be 0.95 to 1.1 times, preferably 0.97 to 1.07 times, and more preferably 0.99 to 1.05 times, of the distance T45 between the image-side surface 144 of the fourth lens 140 and the object-side surface 152 of the fifth lens 150. When the distance between the first lens group G1 and the second lens group G2 of the present disclosure (that is, the distance T56 between the image-side surface 154 of the fifth lens 150 and the object-side surface 162 of the sixth lens 160) satisfies the above conditions, light passing through the first lens group G1 may be uniformly propagated through the second lens group G2 and uniformly reach each peripheral pixel of the image sensor 180.

[0095] When at least one of the refractive power of the first to sixth lenses, the shape of the lens surface, the center thickness of the lens, and the distance between the lenses satisfies the above conditions, the first lens group G1 can be used to collect light and correct chromatic aberration, and the second lens group G2 can be used to make the light spread evenly to each outer edge pixel of the image sensor. That is, according to an embodiment of the present disclosure, the effective diameter of the object side surface 112 of the first lens 110 is designed to be smaller than the image sensor 180 to reduce the head size of the optical system 100. To be precise, the effective diameter of the object side surface 112 of the first lens 110 is designed to be smaller than the image sensor 180, and when the distance between the lenses in the first lens group G1 satisfies the above conditions, even when the effective diameter of the object side surface 112 of the first lens 110 is sufficiently small, light can be collected without distortion. In addition, when the distance between the first lens group G1 and the second lens group G2 satisfies the above conditions (that is, when set to be farther than the distance between the lenses in the first lens group G1), the light collected by the first lens group G1 can pass through the second lens group G2 and reach each pixel of the image sensor 170 uniformly without distortion.

[0096] According to an embodiment of the present disclosure, the first lens 110, the second lens 120, the third lens 130, the fourth lens 140, and the fifth lens 150 have positive composite refractive power, and the sixth lens 160 has negative refractive power. That is, the composite refractive power of the first lens 110, the second lens 120, the third lens 130, the fourth lens 140, and the fifth lens 150 may be 0.46, and the refractive power of the sixth lens 160 may be -0.62. Therefore, the first lens 110, the second lens 120, the third lens 130, the fourth lens 140, and the fifth lens 150 may be used to collect light incident on the object side surface of the first lens 110, and the sixth lens 160 may be used to propagate light from the object side surface 142 of the fourth lens 140 to the image side surface 154 of the fifth lens 150, so that the light reaches each pixel of the image sensor 180.

[0097] Specifically, as in an embodiment of the present disclosure, when the first lens 110 has a positive refractive power and the second lens 120 has a negative refractive power, the absolute value of the refractive power P1 of the first lens 110 is 1.5 times or more, preferably 1.7 times or more, and more preferably 2 times or more of the absolute value of the refractive power P2 of the second lens 120, and the center thickness CT1 of the first lens 110 is 3 times or more of the center thickness CT2 of the second lens, the first lens 110 can collect light incident on the optical system 100, and the second lens 120 can correct chromatic aberration.

[0098] In addition, among the distances between adjacent lenses in the optical system 100 , when the distance T56 between the first lens group G1 and the second lens group G2 is the largest, the second lens group G2 may be used to make light spread more uniformly to the outer edge of the image sensor.

[0099] According to an embodiment of the present disclosure, the total track length (TTL), that is, the distance from the object side surface 112 of the first lens 110 to the image sensor 180 is 3 mm to 6.5 mm, preferably 3 mm to 5.5 mm, and more preferably 4 mm to 4.5 mm; the distance from the object side surface 122 of the second lens 120 to the image sensor 180 is 3.4618 mm; the distance from the object side surface 132 of the third lens 130 to the image sensor 180 is 3.2048 mm; the distance from the object side surface 142 of the fourth lens 140 to the image sensor 180 is 2.5666 mm; the distance from the object side surface 152 of the fifth lens 150 to the image sensor 180 is 2.0563 mm; and the distance from the object side surface 162 of the sixth lens 160 to the image sensor 180 is 1.2755 mm. Here, the back focal length (BFL) which is the distance from the image side surface 164 of the sixth lens 160 to the image sensor 180 is 0.8775 mm. In addition, the diagonal length (2*H imageD ) is 6.53801mm. From the perspective of those skilled in the art, considering manufacturability and assemblability, the BFL should be implemented as 0.6mm or more. For example, in the case of a camera device with an autofocus function, in order to assemble the optical system and the image sensor, the BFL should be implemented as 0.7mm or more, and when the optical system includes a circular asymmetric lens, the BFL should be implemented as 0.7mm or more. Since the optical system of the present disclosure includes a circular asymmetric lens, the BFL should be implemented as 0.7mm or more. Therefore, the optical system 100 can be implemented in a compact size and can be built into the front and rear sides of the mobile terminal.

[0100] According to an embodiment of the present disclosure, the effective diameter may gradually increase from the first lens 110 to the sixth lens 160. Here, the effective diameter may refer to a diameter of an effective area of ​​an object-side surface or an image-side surface on which light is incident.

[0101] In this case, the effective diameter (ED) of the image-side surface 164 of the sixth lens 160 is L6S2 ) may be the effective diameter (ED) of the object-side surface 112 of the first lens 110 L1S1 ), preferably 2.5 times or more, and more preferably 3 times or more.

[0102] The effective diameter (ED) of the image-side surface 164 of the sixth lens 160 is L6S2 ) may be an effective diameter (ED) of the image-side surface 154 of the fifth lens 150 L5S2 ) is 1.2 times or more, preferably 1.25 times or more, and more preferably 1.3 times or more. The effective diameter (ED L6S2 ) may be smaller than the diagonal length of the image sensor 180 (2*H imageD ).

[0103] Therefore, light is uniformly dispersed from the first lens to the sixth lens, and the amount of light reaching the outer edge of the image sensor 180 can be increased.

[0104] Figure 7 is design data showing the distance between lens surfaces according to the distance from the optical axis in the Y direction in the optical system according to the embodiment of the present disclosure, Figure 8 are design data showing sag values ​​of lens surfaces according to distances from the optical axis in the Y direction in the first lens to the fifth lens of the optical system according to an embodiment of the present disclosure, Fig. 9 is design data showing sag values ​​of the lens surface according to distances from the optical axis in the X direction, the Y direction, the diagonal direction, and the 45-degree direction in the sixth lens of the optical system according to an embodiment of the present disclosure, Fig.10 is design data showing the inclination angle of the lens surface according to the distance from the optical axis in the Y direction in the optical system according to the embodiment of the present disclosure. Figures 7 to 10, L1, L2, L3, L4, L5 and L6 respectively represent the first lens 110, the second lens 120, the third lens 130, the fourth lens 140, the fifth lens 150 and the sixth lens 160, and L1S1, L1S2, L2S1, L2S2, L3S1, L3S2, L4S1, L4S2, L5S1, L5S2, L6S1 and L6S2 respectively represent the object-side surface 112 and the image-side surface 114 of the first lens 110, the object-side surface 122 and the image-side surface 124 of the second lens 120, the object-side surface 132 and the image-side surface 134 of the third lens 130, the object-side surface 142 and the image-side surface 144 of the fourth lens 140, the object-side surface 152 and the image-side surface 154 of the fifth lens 150 and the object-side surface 162 and the image-side surface 164 of the sixth lens 160. The air gap (air) between L1 and L2 represents the distance between the first lens 110 and the second lens 120, the air gap between L2 and L3 represents the distance between the second lens 120 and the third lens 130, the air gap between L3 and L4 represents the distance between the third lens 130 and the fourth lens 140, the air gap between L4 and L5 represents the distance between the fourth lens 140 and the fifth lens 150, and the air gap between L5 and L6 represents the distance between the fifth lens 150 and the sixth lens 160.

[0105] Reference Figure 7 , the distance between the image-side surface 114 of the first lens 110 and the object-side surface 122 of the second lens 120 can be uniformly maintained from the optical axis to the end of the image-side surface 114 of the first lens 110. Here, the end of the lens surface may refer to the end of the effective area of ​​the lens surface. Here, the optical axis may refer to a point where the distance in the Y direction is 0. Here, when the ratio of the maximum distance to the minimum distance between the opposite surfaces of different lenses from the optical axis to the end of the lens surface is 3 times or less, it can be interpreted that the distance between the opposite surfaces of different lenses is uniformly maintained.

[0106] That is, the maximum distance (T12 between the image-side surface 114 of the first lens 110 and the object-side surface 122 of the second lens 120 from the optical axis to the end of the image-side surface 114 of the first lens 110 is max ) and the minimum distance (T12 min ) may be less than 3 times. In this case, the distance between the image-side surface 114 of the first lens 110 and the object-side surface 122 of the second lens 120 may tend to gradually decrease from the optical axis to the end of the image-side surface 114 of the first lens 110.

[0107] On the other hand, the distance between the image-side surface 124 of the second lens 120 and the object-side surface 132 of the third lens 130 from the optical axis to the end of the image-side surface 124 of the second lens 120 may be maintained unevenly. That is, the maximum distance (T234) between the image-side surface 124 of the second lens 120 and the object-side surface 132 of the third lens 130 from the optical axis to the end of the image-side surface 124 of the second lens 120 is not uniform. max ) and the minimum distance (T23 min ) may exceed 3 times. In this case, the distance between the image-side surface 124 of the second lens 120 and the object-side surface 132 of the third lens 130 tends to gradually increase from the optical axis to the end of the image-side surface 124 of the second lens 120. When the distances between the first lens 110, the second lens 120, and the third lens 130 have the above-mentioned tendency, light can be collected from the first lens 110 to the object-side surface 132 of the third lens 130.

[0108] In addition, the distance between the image-side surface 134 of the third lens 130 and the object-side surface 142 of the fourth lens 140 can be uniformly maintained from the optical axis to the end of the image-side surface 134 of the third lens 130. That is, the maximum distance (T34) between the image-side surface 134 of the third lens 130 and the object-side surface 142 of the fourth lens 140 from the optical axis to the end of the image-side surface 134 of the third lens 130 is max ) and the minimum distance (T34 min ) can be 3 times or less, preferably 2 times or less, and more preferably 1.5 times or less.

[0109] Similarly, the distance between the image-side surface 144 of the fourth lens 140 and the object-side surface 152 of the fifth lens 150 can be uniformly maintained from the optical axis to the end of the image-side surface 144 of the fourth lens 140. That is, the maximum distance (T45 max ) and minimum distance (T45 min ) can be 3 times or less, preferably 2 times or less, more preferably 1.5 times or less, and even more preferably 1.3 times or less.

[0110] On the other hand, the distance between the image-side surface 154 of the fifth lens 150 and the object-side surface 162 of the sixth lens 160 from the optical axis to the end of the image-side surface 154 of the fifth lens 150 may be maintained unevenly. That is, the maximum distance (T56 max ) and the minimum distance (T56min ) may exceed 3 times. In this case, the distance between the image-side surface 154 of the fifth lens 150 and the object-side surface 162 of the sixth lens 160 may tend to gradually decrease from the optical axis to the end of the effective area of ​​the image-side surface 154 of the fifth lens 150. When the distance between the fifth lens 150 and the sixth lens 160 has the above-mentioned tendency, light emitted from the image-side surface 154 of the fifth lens 150 and incident on the object-side surface 162 of the sixth lens 160 may be uniformly dispersed on the object-side surface 162 of the sixth lens 160.

[0111] In addition, refer to Figure 7 , among the first to sixth lenses forming the optical system 100 according to an embodiment of the present disclosure, the thickness at the end of the effective area in the sixth lens 160 is the largest, and the thickness at the end of the effective area in the first lens 110 is the second largest. In addition, the thickness ST1 of the end of the effective area of ​​the first lens 110 may be 0.7 to 0.95 times, preferably 0.75 to 0.9 times, and more preferably 0.8 to 0.85 times the central thickness CT1 of the first lens 110. Therefore, it is easy to manufacture the first lens 110 with a small effective diameter, thereby minimizing the head size.

[0112] In addition, refer to Figures 8 to 10 According to an embodiment of the present disclosure, at least one surface of at least one of the first to sixth lenses forming the optical system 100 includes a critical point. The critical point may refer to a point at which a trend of a sag value changes. The sag value refers to a distance on the optical axis between an arbitrary point on the lens surface and a point on the optical axis. The point at which a trend of a sag value changes may be a point at which the sag value increases and then decreases, or a point at which the sag value decreases and then increases. The critical point may refer to a point at which an inclination angle becomes 0. The inclination angle may be defined as an angle formed by a normal line of a tangent line of a lens surface and the optical axis.

[0113] According to an embodiment of the present disclosure, at least one of the six surfaces of the first lens 110, the second lens 120, and the third lens 130 includes a critical point. For example, according to an embodiment of the present disclosure, at least one of the image side surface 114 of the first lens 110, the object side surface 122 of the second lens 120, the image side surface 124 of the second lens 120, and the image side surface 134 of the third lens 130 includes a critical point. Light is more effectively refracted near the critical point. That is, light passing through the lens surface including the critical point can be more effectively refracted than light passing through the lens surface not including the critical point. Therefore, when at least one of the six surfaces of the first lens 110, the second lens 120, and the third lens 130 includes a critical point, light incident through the effective diameter of the object side surface 112 of the first lens 110 can be refracted in the widest possible range between the first lens to the third lens, the light can uniformly reach the outer edge pixels of the image sensor 180, and even when the effective diameter of the object side surface 112 of the first lens 110 is designed to be small to minimize the head size, the performance of the optical system 100 can be enhanced.

[0114] In addition, according to an embodiment of the present disclosure, at least two of the six surfaces of the fourth lens 140, the fifth lens 150, and the sixth lens 160 include a critical point. In this case, at least one of the image side surface 154 of the fifth lens 150 and the object side surface 162 of the sixth lens 160 may not include a critical point, and the image side surface 164 of the sixth lens 160 may include a critical point. Light is more effectively refracted near the critical point. When a critical point exists on the outer edge of the image side surface 164 of the sixth lens 160, which is the lens surface closest to the image sensor 180, light refracted at the outer edge of the image side surface 164 of the sixth lens 160 can easily and uniformly reach the outer edge pixels of the image sensor 180. The outer edge may be an area closer to the effective diameter area than the optical axis. Specifically, when a critical point exists on the image-side surface 164 of the sixth lens 160 which is a lens surface closest to the image sensor 180, manufacturability and assemblability of the optical system 100 can be improved compared to when a critical point exists on the image-side surface or the object-side surface of the first lens 110 which is a lens surface farthest from the image sensor 180. Even when the sixth lens 160 is slightly tilted during assembly, since assembly of the first to fifth lenses of the optical system 100 is not affected, optical performance is not significantly affected, so assemblability of the optical system 100 can be improved.

[0115] More specifically, according to an embodiment of the present disclosure, the critical point of the image-side surface 114 of the first lens 110 may be a point having a vertical distance of 0.6 mm to 0.8 mm, preferably 0.7 mm to 0.8 mm from the optical axis. For example, when the optical axis is the starting point and the end of the image-side surface 114 of the first lens 110 is the end point, the critical point of the image-side surface 114 of the first lens 110 may be set at a position of 80% to 100%, preferably 85% to 95%, and more preferably 87% to 92%. Here, the end of the lens surface may refer to the end of the effective area of ​​the lens surface, and the position of the critical point may be a position set based on a direction perpendicular to the optical axis.

[0116] According to an embodiment of the present disclosure, the critical point of the object-side surface 122 of the second lens 120 may be a point having a vertical distance of 0.3 mm, preferably 0.1 mm to 0.2 mm from the optical axis. For example, when the optical axis is the starting point and the end of the object-side surface 122 of the second lens 120 is the end point, the critical point of the object-side surface 122 of the second lens 120 may be set at a position of 5% to 30%, preferably 10% to 25%.

[0117] According to an embodiment of the present disclosure, the critical points of the image-side surface 114 of the first lens 110 and the object-side surface 122 of the second lens 120 may be set in an area that does not face each other, wherein the image-side surface 114 and the object-side surface 122 are surfaces that face each other. That is, the critical point of the image-side surface 114 of the first lens 110 is set near the edge of the effective area of ​​the image-side surface 114 of the first lens 110, and the critical point of the object-side surface 122 of the second lens 120 is set near the optical axis of the object-side surface 122 of the second lens 120. Therefore, since light is refracted near each of the critical points of the image-side surface 114 of the first lens 110 and the object-side surface 122 of the second lens 120, light at different distances from the optical axis can be uniformly refracted.

[0118] According to an embodiment of the present disclosure, the critical point of the image-side surface 124 of the second lens 120 may be a point having a vertical distance of 0.4 mm to 0.7 mm, preferably 0.5 mm to 0.6 mm from the optical axis. For example, when the optical axis is the starting point and the end of the image-side surface 124 of the second lens 120 is the end point, the critical point of the image-side surface 124 of the second lens 120 may be set at a position of 40% to 70%, preferably 45% to 65%.

[0119] According to an embodiment of the present disclosure, the critical point of the image-side surface 134 of the third lens 130 may be a point having a vertical distance of 0.8 mm to 1.1 mm, preferably 0.9 mm to 1.0 mm from the optical axis. For example, when the optical axis is the starting point and the end of the image-side surface 134 of the third lens 130 is the end point, the critical point of the image-side surface 134 of the third lens 130 may be set at a position of 75% to 100%, preferably 80% to 95%.

[0120] Therefore, when there is a critical point on at least one of the six surfaces of the first lens to the third lens (for example, on four surfaces), light can be uniformly dispersed in the first lens to the third lens, output through the image side surface 134 of the third lens 130, and incident on the object side surface 142 of the fourth lens 140.

[0121] According to an embodiment of the present disclosure, the object-side surface 142 of the fourth lens 140, the image-side surface 144 of the fourth lens 140, and the object-side surface 152 of the fifth lens 150 successively include critical points, and all critical points of the object-side surface 142 of the fourth lens 140, the image-side surface 144 of the fourth lens 140, and the object-side surface 152 of the fifth lens 150 can be set at a point with a vertical distance of 0.6 mm to 0.9 mm, preferably 0.7 mm to 0.9 mm from the optical axis. The ratio of the distance between the optical axis and the critical point of the image-side surface 144 of the fourth lens 140 to the distance between the optical axis and the critical point of the object-side surface 142 of the fourth lens 140 may be 0.9 to 1.1 times, preferably 0.95 to 1.05 times, and more preferably 0.97 to 1.03 times, and the ratio of the distance between the optical axis and the critical point of the object-side surface 152 of the fifth lens 150 to the distance between the optical axis and the critical point of the object-side surface 142 of the fourth lens 140 may be 0.9 to 1.3 times, preferably 1 to 1.3 times. When the above conditions are satisfied, light uniformly dispersed through the first to third lenses, output through the image-side surface 134 of the third lens 130, and then incident on the object-side surface 142 of the fourth lens 140 may be uniformly dispersed and incident from the center to the outer edge of the fourth and fifth lenses.

[0122] According to an embodiment of the present disclosure, the image-side surface 154 of the fifth lens 150 and the object-side surface 162 of the sixth lens 160 do not include a critical point, the image-side surface 154 of the fifth lens 150 is convex toward the image side, and the object-side surface 162 of the sixth lens 160 is concave toward the object side. In addition, the curvature radius (R L5S2 ) may be the absolute value of the curvature radius (R L6S1), preferably 0.95 times to 1.1 times the absolute value of ), preferably 0.95 times to 1.1 times. When the image-side surface 154 of the fifth lens 150 and the object-side surface 162 of the sixth lens 160 satisfy the above conditions, light uniformly dispersed in the first to fifth lenses, output through the image-side surface 154 of the fifth lens 150, and then incident on the object-side surface 162 of the sixth lens 160 can be uniformly dispersed and output from the center to the outer edge of the image-side surface 164 of the sixth lens 160.

[0123] In this case, the distance between the image-side surface 154 of the fifth lens 150 and the object-side surface 162 of the sixth lens 160 may tend to gradually decrease as they are away from the optical axis. For example, the distance between the image-side surface 154 of the fifth lens 150 and the object-side surface 162 of the sixth lens 160 may decrease to a vertical distance corresponding to a critical point of the image-side surface 164 of the sixth lens 160 from the optical axis.

[0124] According to an embodiment of the present disclosure, each of the object-side surface 142 and the image-side surface 144 of the fourth lens 140, the object-side surface 152 and the image-side surface 154 of the fifth lens 150, and the object-side surface 162 of the sixth lens 160 may have a maximum inclination angle of 25 degrees or more with respect to the optical axis at a vertical distance corresponding to a critical point in the Y-axis direction of the image-side surface 164 of the sixth lens 160. Therefore, assemblability and manufacturability of the optical system may be improved, and light may be uniformly dispersed and output from the center to the outer edge of the object-side surface 162 of the sixth lens 160.

[0125] According to an embodiment of the present disclosure, the first to fifth lenses are circularly symmetrical lenses, and the sixth lens 160 is a lens whose two surfaces have circular asymmetrical shapes.

[0126] Reference Fig. 9, both the object-side surface 162 and the image-side surface 164 of the sixth lens 160 have circular asymmetric shapes. When both the object-side surface 162 and the image-side surface 164 of the sixth lens 160 have circular asymmetric shapes, optical distortion can be minimized, an optical angle can be achieved, and RI can be increased while reducing the total number of lenses included in the optical system 100. The circular asymmetric shape may refer to that the shape of the lens cross section is different in the X-axis direction and the Y-axis direction centered on the optical axis, the shape of the lens cross section is different in the third direction between the X-axis direction and the Y-axis direction and the X-axis direction, or the shape of the lens cross section is different in the third direction between the X-axis direction and the Y-axis direction and the Y-axis direction. Here, the third direction may refer to a diagonal direction of the image sensor or a 45-degree direction between the X-axis and the Y-axis. When the X-axis length and the Y-axis length of the image sensor are the same, the diagonal direction of the image sensor and the 45-degree direction between the X-axis and the Y-axis may be the same. When the X-axis length and the Y-axis length of the image sensor are different, for example, when the ratio of the X-axis length to the Y-axis length of the image sensor is 4 to 3, the angle between the X-axis direction and the diagonal direction may be less than 45 degrees, and the angle between the Y-axis direction and the diagonal direction may be greater than 45 degrees. Here, the different shapes may refer to different inclination angles, different sag values, or if there is a critical point, the points where the critical point appears are different. For example, the different shapes in the X-axis direction and the Y-axis direction may refer to a region where the inclination angle in the X-axis direction and the inclination angle in the Y-axis direction are different from each other when the distance from the optical axis is the same, or a region where the sag value in the X-axis direction and the sag value in the Y-axis direction are different from each other when the distance from the optical axis is the same. When there is a critical point, the different shapes in the X-axis direction and the Y-axis direction may refer to a distance between the optical axis and the critical point in the X-axis direction and a distance between the optical axis and the critical point in the Y-axis direction are different from each other. Circular asymmetric shape may be used interchangeably with free surface shape, autonomous surface shape, rotationally asymmetric shape, free form shape, origin asymmetric, etc.

[0127] According to an embodiment of the present disclosure, at the object-side surface 162 of the sixth lens 160, there is a deviation between the sag value in the X direction and the sag value in the Y direction. According to an embodiment of the present disclosure, at the object-side surface 162 of the sixth lens 160, at least three of the sag value in the X direction, the sag value in the Y direction, the sag value in the direction of 45 degrees to the X axis (hereinafter, referred to as the 45 degree direction), and the sag value in the diagonal direction of the image sensor 180 are different from each other. According to an embodiment of the present disclosure, at the object-side surface 162 of the sixth lens 160, the sag value in the X direction, the sag value in the Y direction, the sag value in the direction of 45 degrees to the X axis (hereinafter, referred to as the 45 degree direction), and the sag value in the diagonal direction of the image sensor 180 are different from each other.

[0128] As mentioned above, the sag value refers to the distance on the optical axis between any point on the lens surface and a point on the optical axis. Fig. 9 In the above description, a positive sag value refers to a shape that protrudes to the right from the optical axis, and a negative sag value refers to a shape that protrudes to the left from the optical axis. It is obvious to those skilled in the art that the sign of the sag value can be defined in the opposite way. For example, a negative sag value can also refer to a shape that protrudes to the right from the optical axis, and a positive sag value can also refer to a shape that protrudes to the left from the optical axis.

[0129] For example, at the object-side surface 162 of the sixth lens 160, the sag value (Sag L6S1_X ), the sag value in the Y direction (Sag L6S1_Y ), the sag value in the 45 degree direction (Sag L6S1_45 ) and the sag value in the diagonal direction of the image sensor (Sag L6S1_D ) may be 0.001 μm to 50 μm. For example, at the object-side surface 162 of the sixth lens 160, the sag value (Sag L6S1_X ), the sag value in the Y direction (Sag L6S1_Y ), the sag value in the 45 degree direction (Sag L6S1_45 ) and the sag value in the diagonal direction of the image sensor (Sag L6S1_D ) may be greater in the second region that is at a second distance from the first region in a direction away from the optical axis than in the first region that is at a first distance from the optical axis. Here, the second distance may be more than 50% of the effective region of the object-side surface 162 of the sixth lens 160, preferably more than 60%, and more preferably more than 70%. For example, in an embodiment where the effective diameter of the object-side surface 162 of the sixth lens 160 is 4.362 mm, in a region where the vertical distance from the optical axis is more than 1.09 mm, preferably more than 1.31 mm, more preferably more than 1.53 mm, and even more preferably more than 1.6 mm, the sag value (Sag) in the X direction is L6S1_X ), the sag value in the Y direction (Sag L6S1_Y ), the sag value in the 45 degree direction (Sag L6S1_45 ) and the sag value in the diagonal direction of the image sensor (Sag L6S1_D ) may have a deviation of 2 μm or more, preferably 2 μm to 50 μm.

[0130] Therefore, since the object-side surface 162 of the sixth lens 160 is a circular asymmetric lens, the same level of light dispersion effect as when multiple lenses overlap can be obtained. Therefore, even in a narrow space, light passing through the object-side surface 162 of the sixth lens 160 can be more evenly dispersed and reach the outer edge pixels of the image sensor 180.

[0131] According to an embodiment of the present disclosure, at the image-side surface 164 of the sixth lens 160, there is a deviation between the sag value in the X direction and the sag value in the Y direction. According to an embodiment of the present disclosure, at the image-side surface 164 of the sixth lens 160, at least three of the sag value in the X direction, the sag value in the Y direction, the sag value in the direction of 45 degrees to the X axis (hereinafter, referred to as the 45 degree direction), and the sag value in the diagonal direction of the image sensor 180 are different from each other. According to an embodiment of the present disclosure, at the image-side surface 164 of the sixth lens 160, the sag value in the X direction, the sag value in the Y direction, the sag value in the direction of 45 degrees to the X axis (hereinafter, referred to as the 45 degree direction), and the sag value in the diagonal direction of the image sensor 180 are different from each other.

[0132] For example, at the image-side surface 164 of the sixth lens 160, the sag value (Sag L6S2_X ), the sag value in the Y direction (Sag L6S2_Y ), the sag value in the 45 degree direction (Sag L6S2_45 ) and the sag value in the diagonal direction of the image sensor (Sag L6S2_D ) may have a deviation of 0.001 μm to 200 μm. For example, at the image-side surface 164 of the sixth lens 160, the sag value (Sag L6S2_x ), the sag value in the Y direction (Sag L6S2_Y ), the sag value in the 45 degree direction (Sag L6S2_45 ) and the sag value in the diagonal direction of the image sensor (Sag L6S2_D ) may be greater in the second region that is at a second distance from the first region in a direction away from the optical axis than in the first region that is at a first distance from the optical axis. Here, the second distance may be more than 50% of the effective area of ​​the image-side surface 164 of the sixth lens 160, preferably more than 55%, and more preferably more than 60%. For example, in an embodiment where the effective diameter of the image-side surface 164 of the sixth lens 160 is 5.048 mm, in a region where the vertical distance from the optical axis is more than 1.262 mm, preferably more than 1.388 mm, more preferably more than 1.51 mm, and even more preferably more than 1.6 mm, the sag value (Sag) in the X direction is L6S2_X ), the sag value in the Y direction (Sag L6S2_Y), the sag value in the 45 degree direction (Sag L6S2_45 ) and the sag value in the diagonal direction of the image sensor (Sag L6S2_D ) may have a deviation of 2 μm or more, preferably 2 μm to 200 μm.

[0133] Therefore, since the image side surface 164 of the sixth lens 160 is a circular asymmetric lens, the same level of light dispersion effect as when multiple lenses overlap can be obtained. Therefore, even in a narrow space, light passing through the image side surface 164 of the sixth lens 160 can be more evenly dispersed and reach the outer edge pixels of the image sensor 180.

[0134] According to an embodiment of the present disclosure, the image-side surface 164 of the sixth lens 160 may have a critical point.

[0135] Fig.11 An image-side surface of a sixth lens and an image sensor of an optical system according to an embodiment of the present disclosure are shown.

[0136] Reference Fig.11 , the distance between the critical point of the image-side surface 164 of the sixth lens 160 on the X-axis and the optical axis may be 0.9 to 1.1 times, preferably 0.95 to 1.05 times, and more preferably 0.97 to 1.03 times, of the distance between the critical point of the image-side surface 164 of the sixth lens 160 on the Y-axis and the optical axis. The distance between the critical point of the image-side surface 164 of the sixth lens 160 on the X-axis and the optical axis may be 0.9 to 1.1 times, preferably 0.95 to 1.05 times, and more preferably 0.97 to 1.03 times, of the distance between the critical point of the image-side surface 164 of the sixth lens 160 in the 45-degree direction and the optical axis. The distance between the critical point of the image side surface 164 of the sixth lens 160 and the optical axis may be 0.9 to 1.1 times, preferably 0.95 to 1.05 times, and more preferably 0.97 to 1.03 times, of the distance between the critical point of the image side surface 164 of the sixth lens 160 in the diagonal direction and the optical axis. For example, the critical point of the X axis, the critical point of the Y axis, the critical point in the 45 degree direction, and the critical point in the diagonal direction of the image side surface 164 of the sixth lens 160 may all be points having a vertical distance of 1.1 mm to 1.4 mm, preferably 1.2 mm to 1.3 mm from the optical axis. For example, the critical point of the X axis, the critical point of the Y axis, the critical point in the 45 degree direction, and the critical point in the diagonal direction of the image side surface 164 of the sixth lens 160 may all be points that are 40% to 60%, preferably 44% to 56%, and more preferably 48% to 52% of the effective area based on the optical axis. Therefore, when a critical point exists on the image-side surface 164 of the sixth lens 160 , the dispersion characteristic of light passing through the image-side surface 164 of the sixth lens 160 may be maximized.

[0137] According to an embodiment of the present disclosure, at the image side surface 164 of the sixth lens 160, at least three of the sag value of the critical point in the X direction, the sag value of the critical point in the Y direction, the sag value of the critical point in the direction of 45 degrees to the X axis (hereinafter, referred to as the 45 degree direction), and the sag value of the critical point on the diagonal line of the image sensor 180 are different from each other. According to an embodiment of the present disclosure, at the image side surface 164 of the sixth lens 160, the sag value in the X direction, the sag value in the Y direction, the sag value in the direction of 45 degrees to the X axis (hereinafter, referred to as the 45 degree direction), and the sag value in the diagonal line of the image sensor 180 are different from each other. Therefore, since the image side surface 164 of the sixth lens 160 has a circular asymmetric shape, the effect of multiple lenses can be obtained using a single lens, so that effective light dispersion can be expected in a narrow space, and light can reach the outer edge pixels of the image sensor 180 uniformly.

[0138] Reference Fig. 9 , the deviation between the sag value of the critical point of the X axis and the sag value of the critical point in the 45 degree direction of the image side surface 164 of the sixth lens 160 may be greater than the deviation between the sag value of the critical point of the X axis and the sag value of the critical point of the Y axis. For example, the deviation between the sag value of the critical point of the X axis and the sag value of the critical point of the Y axis of the image side surface 164 of the sixth lens 160 may be greater than 0.001 pm and less than 1 μm, while the deviation between the sag value of the critical point of the X axis and the sag value of the critical point in the 45 degree direction may exceed 1 μm. Alternatively, among the absolute value of the sag value of the critical point of the X axis, the absolute value of the sag value of the critical point of the Y axis, and the absolute value of the sag value of the critical point in the 45 degree direction of the image side surface 164 of the sixth lens 160, the absolute value of the sag value of the critical point in the 45 degree direction may be the smallest. Therefore, when the sag value of the critical point of the X-axis, the sag value of the critical point of the Y-axis, the sag value of the critical point in the 45-degree direction, and the sag value of the critical point in the diagonal direction of the image side surface 164 of the sixth lens 160 are different from each other, since the image side surface 164 of the sixth lens 160 has a circular asymmetric shape, a single lens can be used to obtain the effect of multiple lenses, so effective light dispersion can be expected in a narrow space, and the light can reach the outer edge pixels of the image sensor 180 uniformly.

[0139] According to an embodiment of the present disclosure, the maximum tilt angle at the image side surface 164 of the sixth lens 160 may be set from the critical point to the edge. According to an embodiment of the present disclosure, the maximum tilt angle from the critical point of the image side surface 164 of the sixth lens 160 to the edge of the image side surface 164 of the sixth lens 160 may be 5 to 10 times, preferably 7 to 10 times, the maximum tilt angle between the optical axis and the critical point. In this case, within the range of 60% to 90% of the effective diameter of the image side surface 164 of the sixth lens 160, the maximum tilt angle may be 65 degrees or less. Therefore, the manufacturing performance can be improved while satisfying the optical performance.

[0140] Therefore, the splitting characteristic of light passing through the image-side surface 164 of the sixth lens 160 can be maximized, and the RI can be improved.

[0141] The optical system 100 according to the embodiment of the present disclosure may satisfy at least one of the following conditional expressions. Therefore, the optical system 100 according to the embodiment of the present disclosure may have an optical enhancement effect. Specifically, at the half value (H ) of the diagonal length of the pixel area of ​​the image sensor 180, imageD ) is 3.2690 mm, the optical system 100 according to an embodiment of the present disclosure can obtain optical performance with an effective focal length (EFL) of 3.478 mm, an F number of less than 2.3, a FOV of more than 85 degrees in the diagonal direction and an RI of more than 30% in one field.

[0142] [Formula 1-1]

[0143] 0.15<ED L1S1 / 2H imageD <0.35

[0144] [Formula 1-2]

[0145] 0.2<ED L1S1 / 2H imageD <0.3

[0146] [Formula 1-3]

[0147] 0.22<ED L1S1 / 2H imageD <0.26

[0148] Here, H imageD is the half value of the diagonal length of the pixel area of ​​the image sensor 180. According to [Formula 1-1] to [Formula 1-3], since the area of ​​the object-side surface 112 of the first lens 110 exposed to the outside can be minimized within the range in which the first lens 110 can be manufactured, the head size of the optical system 100 can be minimized. L1S1 / 2H imageDWhen the value is less than the lower limit of the above numerical range, it may be difficult to manufacture the first lens 110, and when the ED L1S1 / 2H imageD When the upper limit is exceeded, it may be difficult to realize an optical system with a small head size.

[0149] [Formula 2-1]

[0150] 3mm≤TTL≤6.5mm

[0151] [Formula 2-2]

[0152] 3mm≤TTL≤5.5mm

[0153] [Formula 2-3]

[0154] 4mm≤TTL≤4.5mm

[0155] Here, TTL is the distance from the object-side surface 112 of the first lens 110 to the image sensor 180. When TTL is less than the lower limit of [Formula 2-1] to [Formula 2-3], manufacturability is poor and it may be difficult to achieve a preferred effective focal length, and when TTL exceeds the upper limit of [Formula 2-1] to [Formula 2-3], the size of the camera device increases, and thus it may be difficult to implement a compact-sized camera device in a mobile terminal.

[0156] [Formula 3-1]

[0157] 0.9≤TTL / EFL≤1.5

[0158] [Formula 3-2]

[0159] 1.0≤TTL / EFL≤1.5

[0160] [Formula 3-3]

[0161] 1.1≤TTL / EFL≤1.3

[0162] Here, EFL is the effective focal length. According to [Formula 3-1] to [Formula 3-3], a high-resolution image can be obtained even in a narrow space. When TTL / EFL is less than the lower limit of the above numerical range, manufacturability is poor and it may be difficult to achieve the preferred effective focal length. When TTL / EFL exceeds the upper limit of the above numerical range, the size of the camera device increases, so it may be difficult to implement a compact-sized camera device in a mobile terminal.

[0163] [Formula 4-1]

[0164] 0.5≤TTL / 2*H imageD ≤0.9

[0165] [Formula 4-2]

[0166] 0.55≤TTL / 2*H imageD ≤0.8

[0167] [Formula 4-3]

[0168] 0.61≤TTL / 2*H imageD ≤0.69

[0169] According to [Equation 4-1] to [Equation 4-3], a high-resolution image can be obtained even in a narrow space. imageD When the value is less than the lower limit of the above numerical range, the manufacturability is poor and it may be difficult to achieve the preferred effective focal length. imageD When the upper limit of the above numerical range is exceeded, the size of the camera device increases, and thus it may be difficult to implement a compact-sized camera device in a mobile terminal.

[0170] [Formula 5-1]

[0171] 2≤TTL / EPD≤3.5

[0172] [Formula 5-2]

[0173] 2.5≤TTL / EPD≤3

[0174] [Formula 5-3]

[0175] 2.65≤TTL / EPD≤2.85

[0176] According to [Formula 5-1] to [Formula 5-3], the head size of the optical system 100 and the overall size of the camera device can be minimized. When TTL / EPD is less than the lower limit of the above numerical range, manufacturability is poor and it may be difficult to achieve a preferred effective focal length, and when TTL / EPD exceeds the upper limit of the above numerical range, the size of the camera device increases, so it may be difficult to implement a compact-sized camera device in a mobile terminal.

[0177] [Formula 6-1]

[0178] 1.422≤ED L1S1 ≤1.738

[0179] [Formula 6-2]

[0180] 1.501≤ED L1S1 ≤1.659

[0181] [Formula 6-3]

[0182] 1.533≤ED L1S1 ≤1.627

[0183] According to [Equation 6-1] to [Equation 6-3], the head size of the optical system 100 can be minimized. L1S1 When the value is less than the lower limit of the above numerical range, it may be difficult to manufacture the first lens 110, and when the ED L1S1 When the upper limit is exceeded, it may be difficult to realize an optical system with a small head size.

[0184] [Formula 7]

[0185] CT1>CT2+CT3

[0186] Here, CT1 is the center thickness of the first lens 110, CT2 is the center thickness of the second lens 120, and CT3 is the center thickness of the third lens 130. Therefore, even when the effective diameter of the object-side surface 112 of the first lens 110 is sufficiently small, light can be collected by the first to third lenses without distortion, and the first to third lenses can serve to collect light and correct chromatic aberration.

[0187] [Formula 8-1]

[0188] CT1 / CT2>2

[0189] [Formula 8-2]

[0190] CT1 / CT2>3

[0191] According to [Equation 8-1] to [Equation 8-2], even when the effective diameter of the object-side surface 112 of the first lens 110 is sufficiently small, light can be collected by the first lens without distortion, and the first lens can be used to collect light and correct chromatic aberration.

[0192] [Formula 9-1]

[0193] CT1>CT4

[0194] [Formula 9-2]

[0195] CT1 / CT4>2

[0196] [Formula 9-3]

[0197] CT1 / CT4>3

[0198] Here, CT4 is the center thickness of the fourth lens 140. Therefore, even when the effective diameter of the object-side surface 112 of the first lens 110 is sufficiently small, light may be collected by the first lens without being distorted.

[0199] [Formula 10]

[0200] CT1>CT5

[0201] Here, CT5 is the center thickness of the fifth lens 150. Therefore, even when the effective diameter of the object-side surface 112 of the first lens 110 is sufficiently small, light may be collected by the first lens without being distorted.

[0202] [Formula 11-1]

[0203] 0.1<CT1 / TTL<0.2

[0204] [Formula 11-2]

[0205] 0.12<CT1 / TTL<0.18

[0206] [Formula 11-3]

[0207] 0.13<CT1 / TTL<0.17

[0208] Therefore, even when the effective diameter of the object-side surface 112 of the first lens 110 is sufficiently small, light can be collected by the first lens without distortion, and the first lens can be used to collect light and correct chromatic aberration. When CT1 / TTL is less than the lower limit of the above numerical range, the effects of collecting light and correcting chromatic aberration of the first lens may be reduced, and when CT1 / TTL exceeds the upper limit of the above numerical range, the manufacturability and assemblability of the first lens may be reduced.

[0209] [Formula 12-1]

[0210] 0.2<CT1 / CT_16<0.35

[0211] [Formula 12-2]

[0212] 0.25<CT1 / CT_16<0.33

[0213] [Formula 12-3]

[0214] 0.27<CT1 / CI_16<0.31

[0215] Therefore, even when the effective diameter of the object-side surface 112 of the first lens 110 is sufficiently small, light can be collected by the first lens without distortion, and the first lens can be used to collect light and correct chromatic aberration. When CT1 / CT_16 is less than the lower limit of the above numerical range, the effect of collecting light and correcting chromatic aberration of the first lens may be reduced, and when CT1 / CT_16 exceeds the upper limit of the above numerical range, the manufacturability and assemblability of the first lens may be reduced.

[0216] [Formula 13-1]

[0217] 1.5≤|P1| / |P2|

[0218] [Formula 13-2]

[0219] 1.7≤|P1| / |P2|

[0220] [Formula 13-3]

[0221] 2≤|P1| / |P2|

[0222] Here, P1 is the diopter of the first lens 110, and P2 is the diopter of the second lens 120. Therefore, the first lens 110 can collect light incident on the optical system 100, and the second lens 120 can correct chromatic aberration. When |P1| / |P2| is less than the lower limit of the above numerical range or exceeds the upper limit of the above numerical range, the effects of collecting light and correcting chromatic aberration of the first lens and the second lens may be reduced.

[0223] [Formula 14]

[0224] 0.7≤BFL

[0225] Here, BFL is the distance from the image side surface 164 of the sixth lens 160 to the image sensor 180. Therefore, even when the optical system 100 includes a circular asymmetric lens, assemblability is excellent. When BFL is not within the above numerical range, assemblability of the optical system 100 may be reduced.

[0226] [Formula 15]

[0227] ED L1S1 <ED L1S2 <ED L2S1 <ED L2S2 <ED L3S1 <ED L3S2 <ED L4S1 <ED L4S2 <ED L5S1 <ED L5S2 <ED L6S1 <ED L6S2 <2*H imageD

[0228] Here, ED LaS1 is the effective diameter of the object side surface of the ath lens, ED LaS2 is the effective diameter of the image-side surface of the a-th lens. Therefore, when light is uniformly dispersed from the first lens 110 to the sixth lens 160, the amount of light reaching the outer edge of the image sensor 180 can be increased.

[0229] [Formula 16-1]

[0230] 2≤ED L6S2 / ED L1S1

[0231] [Formula 16-2]

[0232] 2.5≤ED L6S2 / ]ED L1S1

[0233] [Formula 16-3]

[0234] 3≤ED L6S2 / ED L1S1

[0235] Therefore, the first lens may be used to collect light incident on the optical system 100, and the sixth lens may be used to disperse the light incident on the sixth lens to increase the amount of light reaching the outer edge of the image sensor 180. L6S2 / ED L1S1 When it is out of the above numerical range, it may be difficult to manufacture the first lens or to minimize the head size of the optical system.

[0236] [Formula 17-1]

[0237] 1.2≤ED L6S2 / ED L5S2

[0238] [Formula 17-2]

[0239] 1.25≤ED L6S2 / ED L5S2

[0240] [Formula 17-3]

[0241] 1.3≤ED L6S2 / ED L5S2

[0242] Therefore, the sixth lens may be used to disperse light incident on the sixth lens to increase the amount of light reaching the outer edge of the image sensor 180. L6S2 / ED L5S2 When it is out of the above numerical range, it may be difficult to manufacture the first lens or to minimize the head size of the optical system.

[0243] [Formula 18]

[0244] T12 max / T12 min ≤3

[0245] Here, T12 max is the maximum distance between the image-side surface 114 of the first lens 110 and the object-side surface 122 of the second lens 120, T12 minis the minimum distance between the image-side surface 114 of the first lens 110 and the object-side surface 122 of the second lens 120. Therefore, light can reach the object-side surface 122 of the second lens 120 from the image-side surface 114 of the first lens 110 without being diffused.

[0246] [Formula 19]

[0247] T23 max / T23 min ≤3

[0248] Here, T23 max is the maximum distance between the image-side surface 124 of the second lens 120 and the object-side surface 132 of the third lens 130, T23 min is the minimum distance between the image-side surface 124 of the second lens 120 and the object-side surface 132 of the third lens 130. Therefore, light output from the image-side surface 124 of the second lens 120 may be uniformly dispersed and then may be incident on the object-side surface 132 of the third lens 130 from the optical axis to the end of the object-side surface 132 of the third lens 130.

[0249] [Formula 20-1]

[0250] T34 max / T34 min ≤3

[0251] [Formula 20-2]

[0252] T34 max / T34 min ≤2

[0253] [Formula 20-3]

[0254] T34 max / T34 min ≤1.5

[0255] Here, T34 max is the maximum distance between the image-side surface 134 of the third lens 130 and the object-side surface 142 of the fourth lens 140, T34 min is the minimum distance between the image-side surface 134 of the third lens 130 and the object-side surface 142 of the fourth lens 140. Therefore, light can reach the object-side surface 142 of the fourth lens 140 from the image-side surface 134 of the third lens 130 in a concentrated state without being dispersed.

[0256] [Formula 21-1]

[0257] T45 max / T45 min ≤3

[0258] [Formula 21-2]

[0259] T45 max / T45 min ≤2

[0260] [Formula 21-3]

[0261] T45 max / T45 min ≤1.3

[0262] Here, T45 max is the maximum distance between the image-side surface 144 of the fourth lens 140 and the object-side surface 152 of the fifth lens 150, T45 min is the minimum distance between the image-side surface 144 of the fourth lens 140 and the object-side surface 152 of the fifth lens 150. Therefore, light can reach the object-side surface 152 of the fifth lens 150 from the image-side surface 144 of the fourth lens 140 in a concentrated state without being dispersed.

[0263] [Formula 22]

[0264] T65 max / T65 min >3

[0265] Here, T65 max is the maximum distance between the image-side surface 154 of the fifth lens 150 and the object-side surface 162 of the sixth lens 160, T65 min is the minimum distance between the image-side surface 154 of the fifth lens 150 and the object-side surface 162 of the sixth lens 160. Therefore, light output from the image-side surface 154 of the fifth lens 150 may be uniformly dispersed and then may be incident on the object-side surface 162 of the sixth lens 160 from the optical axis to the end of the object-side surface 162 of the sixth lens 160.

[0266] [Formula 23-1]

[0267] 0.7≤ST1 / CT1≤0.95

[0268] [Formula 23-2]

[0269] 0.75≤ST1 / CT1≤0.9

[0270] [Formula 23-3]

[0271] 0.8≤ST1 / CT1≤0.85

[0272] Here, ST1 is the thickness of the end of the effective area of ​​the first lens 110. Therefore, it is easy to manufacture the first lens 110 with a small effective diameter to minimize the head size. When ST1 / CT1 is less than the lower limit of the above numerical range, it may be difficult to manufacture the first lens and it is difficult to expect a high light collection effect of the first lens, and when ST1 / CT1 exceeds the upper limit of the above numerical range, it may be difficult to manufacture the first lens.

[0273] [Formula 24-1]

[0274] 0.9≤|R L5S2 / R L6S1 |≤1.1

[0275] [Formula 24-2]

[0276] 0.95≤|R L5S2 / R L6S1 |≤1.1

[0277] Here, R L5S2 is the radius of curvature of the image-side surface 154 of the fifth lens 150, R L6S1 is the radius of curvature of the object-side surface 162 of the sixth lens 160. Light uniformly dispersed in the first to fifth lenses, output through the image-side surface 154 of the fifth lens 150, and then incident on the object-side surface 162 of the sixth lens 160 may be uniformly dispersed and output from the center to the outer edge of the image-side surface 164 of the sixth lens 160.

[0278] [Formula 25-1]

[0279] 0.9≤D_CP L4S2 / D_CP L4S1 ≤1.1

[0280] [Formula 25-2]

[0281] 0.95≤D_CP L4S2 / D-CP L4S1 ≤1.05

[0282] [Formula 25-3]

[0283] 0.97≤D_CP L4S2 / D_CP L4S1 ≤1.03

[0284] Here, D_CP L4S1 is the vertical distance between the critical point of the object-side surface 142 of the fourth lens 140 and the optical axis, D_CP L4S2is a vertical distance between a critical point of the image-side surface 144 of the fourth lens 140 and the optical axis. Therefore, light uniformly dispersed through the first to third lenses, output through the image-side surface 134 of the third lens 130, and then incident on the object-side surface 142 of the fourth lens 140 may be uniformly dispersed and incident on the fourth and fifth lenses from their centers to outer edges.

[0285] [Formula 26-1]

[0286] 0.9≤D_CP L5S1 / D_CP L4S1 ≤1.3

[0287] [Formula 26-2]

[0288] 1≤D_CP L5S1 / D_CP L4S1 ≤1.3

[0289] Here, D_CP L5S1 is a vertical distance between a critical point of the object-side surface 152 of the fifth lens 150 and the optical axis. Therefore, light uniformly dispersed through the first to third lenses, output through the image-side surface 134 of the third lens 130, and then incident on the object-side surface 142 of the fourth lens 140 may be uniformly dispersed and incident on the fourth and fifth lenses from their centers to outer edges.

[0290] [Formula 27]

[0291] 0.001μm≤|Sag L56S1_X -Sag L56S1_Y |≤50μm

[0292] Here, Sag L56S1_X is the sag value of the object-side surface 162 of the sixth lens 160 in the X direction, Sag L56S1_Y is the sag value in the Y direction of the object-side surface 162 of the sixth lens 160. Therefore, the light passing through the object-side surface 162 of the sixth lens 160 can be more uniformly dispersed and reach the outer edge pixels of the image sensor 180. L56S1_X -Sag L56S1_Y When | is less than the lower limit of the above numerical range, it may be difficult to expect the effect according to the circular asymmetric shape, and when |Sag L56S1_X -Sag L56S1_Y When the upper limit of the above numerical range is exceeded, the manufacture, design and performance prediction of the sixth lens may be difficult.

[0293] [Equation 28]

[0294] 0.001μm≤|SagL6S1_X -Sag L6S1_D |≤50μm

[0295] Here, Sag L6S1_D is the sag value in the diagonal direction of the object-side surface 162 of the sixth lens 160. Therefore, the light passing through the object-side surface 162 of the sixth lens 160 can be more uniformly dispersed and reach the outer edge pixels of the image sensor 180. L6S1_X -Sag L6S1_D When | is less than the lower limit of the above numerical range, it may be difficult to expect the effect according to the circular asymmetric shape, and when |Sag L6S1_X -Sag L6S1_D When the upper limit of the above numerical range is exceeded, the manufacture, design and performance prediction of the sixth lens may be difficult.

[0296] [Equation 29]

[0297] 0.001μm≤|Sag L6S1_X -Sag L6S1_45 |≤50μm

[0298] Here, Sag L6S1_45 is a sag value in a direction that is 45 degrees to the X direction of the object-side surface 162 of the sixth lens 160. Therefore, light passing through the object-side surface 162 of the sixth lens 160 can be more uniformly dispersed and reach the outer edge pixels of the image sensor 180. L6S1_X -Sag L6S1_45 When | is less than the lower limit of the above numerical range, it may be difficult to expect the effect according to the circular asymmetric shape, and when |Sag L6S1_X -Sag L6S1_45 When the upper limit of the above numerical range is exceeded, the manufacture, design and performance prediction of the sixth lens may be difficult.

[0299] [Formula 30]

[0300] 0.001μm≤|Sag L6S2_X -Sag L6S2_Y |≤200μm

[0301] Here, Sag L6S2_X is the sag value of the image-side surface 164 of the sixth lens 160 in the X direction, Sag L6S2_Yis the sag value in the Y direction of the image side surface 164 of the sixth lens 160. Therefore, the light passing through the object side surface 162 of the sixth lens 160 can be more uniformly dispersed and reach the outer edge pixels of the image sensor 180. In addition, since the effect of a plurality of lenses arranged in an overlapping manner can be obtained using a single sixth lens 160, the optical performance can be improved while realizing the optical system 100 in a small size. L6S2_X -Sag L6S2_Y When | is less than the lower limit of the above numerical range, it may be difficult to expect the effect according to the circular asymmetric shape, and when |Sag L6S2_X -Sag L6S2_Y When the upper limit of the above numerical range is exceeded, the manufacture, design and performance prediction of the sixth lens may be difficult.

[0302] [Equation 31]

[0303] |CP_Sag L6S1_X -CP_Sag L6S1_Y |<|CP_Sag L6S1_X -CP_Sag L6S1_45 |

[0304] Here, CP_Sag L6S1_X is the sag value of the critical point in the X direction of the object side surface 162 of the sixth lens 160, CP_Sag L6S1_Y is the sag value of the critical point in the Y direction of the object side surface 162 of the sixth lens 160, CP_Sag L6S1_D is the sag value of the critical point in the 45 degree direction of the object-side surface 162 of the sixth lens 160. Therefore, since the effect of a plurality of lenses arranged in an overlapping manner can be obtained using a single lens, the optical performance can be improved while implementing the optical system 100 in a small size.

[0305] Table 5 shows chief ray angle (CRA) data and RI values ​​by field that can be obtained using an optical system according to an embodiment of the present disclosure, Fig.12 shows the modulation transfer function (MTF) of an optical system using one embodiment of the present disclosure, Fig.13 A distortion grid using an optical system according to one embodiment of the present disclosure is shown.

[0306] [Table 5]

[0307] field CRA RI(%) 0 0 100.0％ 0.1 7.79839 99.1％ 0.2 15.0677 95.3％ 0.3 21.5477 87.2％ 0.4 27.2865 76.0％ 0.5 31.9691 65.0％ 0.6 34.9043 56.8％ 0.7 35.9255 48.8％ 0.8 36.2047 40.5％ 0.9 36.2217 34.0％ l 34.7212 31.4％

[0308] Referring to Table 5, in the optical system according to the embodiment of the present disclosure, it can be seen that: when the chief ray angle (CRA) is greater than 7 degrees, for example, in the range of 8 degrees to 37 degrees, the amount of light at the outer edge (1 field) of the image sensor except for the 0 field is greater than 30%, and the amount of light at the center (0 field) of the image sensor is 100%.

[0309] Reference Fig.12 , the clarity of an image in a spatial frequency according to a pixel that can be obtained from an optical system according to one embodiment of the present disclosure can be obtained, and referring to Fig.13 , the degree of distortion of an image that can be obtained from the optical system according to an embodiment of the present disclosure can be obtained.

[0310] Fig.14 is a cross-sectional view of an optical system according to a comparative example.

[0311] Reference Fig.14 , the optical system 200 according to the comparative example includes a first lens 210, a second lens 220, a third lens 230, a fourth lens 240, a fifth lens 250, a sixth lens 260, a filter 270 and an image sensor 280 which are sequentially arranged from the object side to the image side.

[0312] Tables 6 and 7 below show optical characteristics of lenses included in the optical system according to the comparative example, and Table 8 shows Qcon coefficients of the first to sixth lenses included in the optical system according to the comparative example.

[0313] [Table 6]

[0314]

[0315]

[0316] [Table 7]

[0317]

[0318] [Table 8]

[0319]

[0320] Table 9 shows chief ray angle (CRA) data and RI values ​​by field that can be obtained using the optical system according to the comparative example.

[0321] [Table 9]

[0322] field RI(%) 0 100.0％ 0.1 96.6％ 0.2 89.4％ 0.3 79.3％ 0.4 68.4％ 0.5 58.0％ 0.6 48.8％ 0.7 41.0％ 0.8 33.2％ 0.9 26.5％ l 19.2％

[0323] Reference Fig.14As well as Tables 6 to 8, it can be seen that: except for the sixth lens 260, the optical system 200 according to the comparative example has a design similar to the optical system 100 according to the embodiment of the present disclosure. That is, the optical system 200 according to the comparative example includes six lenses, the first lens 210 closest to the object side has the smallest effective diameter among the first lens to the sixth lens, and the thickness of the first lens 210 is the largest among the first lens to the sixth lens. However, unlike the embodiment of the present disclosure, the sixth lens 260 of the optical system according to the comparative example is a circularly symmetric lens. Referring to Table 9, it can be seen that: the optical system according to the comparative example has an RI of 19.2% in 1 field. It can be seen that: this is significantly different from the optical system according to the embodiment having an RI of 31.4% in 1 field.

[0324] Fig.15 is a view showing a portion of a mobile terminal to which a camera device according to one embodiment of the present disclosure is applied.

[0325] In addition, the optical system 100 according to the embodiment of the present disclosure may be applied to the camera device 1000. The camera device 1000 including the optical system 100 according to the embodiment of the present disclosure may be built in a mobile terminal and applied together with a main camera module. The camera device 1000 according to the embodiment of the present disclosure may include an image sensor, an optical filter disposed on the image sensor, and the optical system 100 disposed on the optical filter, and the optical system 100 according to the embodiment of the present disclosure may include the above-mentioned first lens 110, second lens 120, third lens 130, fourth lens 140, and fifth lens 150. The mobile terminal having a built-in camera device including the optical system according to the embodiment of the present disclosure may be a smart phone, a personal tablet (PC), a laptop computer, a personal digital assistant (PDA), etc.

[0326] Due to the thickness limitation of the mobile terminal, the optical system 100 according to the embodiment of the present disclosure can be sequentially arranged in the lateral direction of the mobile terminal. To this end, as described above, a right angle prism can be further arranged in front of the first lens 110.

[0327] The mobile terminal may be a smart phone, a tablet PC, a notebook computer, a PDA, etc.

[0328] Although the embodiments have been mainly described above, these embodiments are only examples and are not intended to limit the present disclosure, and it can be seen that various modifications and applications not illustrated herein can be made by those skilled in the art without departing from the basic features of the present disclosure. For example, the various components specifically shown in the embodiments can be modified and implemented. In addition, it should be understood that differences related to modifications and applications are included in the scope of the present disclosure as defined by the appended claims.

[0329] [Explanation of Reference Numerals]

[0330] 100: Optical system

[0331] 110: First lens

[0332] 120: Second lens

[0333] 130: The third lens

[0334] 140: The fourth lens

[0335] 150: Fifth lens

[0336] 160: Sixth lens

Claims

1. An optical system comprising a first lens to an nth lens arranged in sequence from an object side to an image side and an image sensor, in, The first lens has positive refractive power and is a lens having the smallest effective area diameter or the largest thickness among the first to n-th lenses, The first lens to the (n-1)th lens have positive compound refractive power, The nth lens has negative refractive power, At least one of the object-side surface and the image-side surface of the nth lens includes a critical point where the inclination angle is 0, A sag value of a critical point of the X axis, a sag value of a critical point of the Y axis, and a sag value of a critical point in one direction between the X axis and the Y axis of at least one of the object side surface and the image side surface of the nth lens are different from each other, The X-axis is perpendicular to the optical axis and parallel to one side of the image sensor, The Y axis is perpendicular to the optical axis and the X axis, and n is an integer greater than or equal to 6.

2. The optical system according to claim 1, wherein: A ratio of a diameter of an effective area of ​​the first lens to a diagonal length of the image sensor is greater than or equal to 0.15 and less than or equal to 0.

35.

3. The optical system according to claim 1, wherein: Among the first to n-th lenses, the center thickness of the first lens on the optical axis is the largest, and Among the first to n-th lenses, a thickness at an end portion of an effective region of the first lens is smaller than a thickness at an end portion of an effective region of the n-th lens.

4. The optical system according to claim 1, wherein: When the center thickness of the first lens on the optical axis is CT1, the distance from the object side surface of the first lens to the image sensor is TTL, and the sum of the center thicknesses of the first lens to the nth lens on the optical axis is CT_ln, CT1 / TTL is greater than 0.1 and less than 0.2, and CT1 / CT_ln is greater than or equal to 0.2 and less than or equal to 0.

35.

5. The optical system according to claim 1, wherein: n is 6.

6. The optical system according to claim 1, wherein: The deviation between the sag value of the critical point of the X-axis and the sag value of the critical point in the direction 45 degrees to the X-axis of at least one of the object-side surface and the image-side surface of the nth lens is greater than the deviation between the sag value of the critical point of the X-axis and the sag value of the critical point of the Y-axis of at least one of the object-side surface and the image-side surface of the nth lens.

7. The optical system according to claim 1, wherein: Among the absolute values ​​of the sag value of the critical point of the X-axis, the absolute value of the sag value of the critical point of the Y-axis, and the absolute value of the sag value of the critical point in the direction 45 degrees to the X-axis of at least one of the object-side surface and the image-side surface of the nth lens, the absolute value of the sag value of the critical point in the direction 45 degrees to the X-axis is the smallest.

8. The optical system according to claim 1, wherein: From a point that is 50% of the effective area of ​​at least one of the object side surface and the image side surface of the nth lens to an end of the effective area, an absolute value of a deviation between at least two of the sag value of the X-axis, the sag value of the Y-axis, the sag value in a direction of 45 degrees to the X-axis, and the sag value in a diagonal direction of the image sensor is greater than 2 μm.

9. The optical system according to claim 1, wherein: Both the object-side surface and the image-side surface of the sixth lens have circular asymmetric shapes.

10. An optical system comprising a first lens to an nth lens arranged in sequence from an object side to an image side and an image sensor, in, The first lens has positive refractive power, A ratio of a diameter of an effective area of ​​the first lens to a diagonal length of the image sensor is greater than or equal to 0.15 and less than or equal to 0.

35. The first lens to the (n-1)th lens have positive compound refractive power, The nth lens has negative refractive power, At least one of the object-side surface and the image-side surface of the nth lens includes a critical point where the inclination angle is 0, A sag value of a critical point of the X axis, a sag value of a critical point of the Y axis, and a sag value of a critical point in one direction between the X axis and the Y axis of at least one of the object side surface and the image side surface of the nth lens are different from each other, The X-axis is perpendicular to the optical axis and parallel to one side of the image sensor, The Y axis is perpendicular to the optical axis and the X axis, and n is an integer greater than or equal to 6.

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