Optical system and camera device including the same

Abstract

The optical system comprises an aperture, a first lens, a second lens, a third lens, a fourth lens and a fifth lens which are sequentially arranged from an object side to an image side, the first lens has positive diopter, the second lens has negative diopter, the third lens has positive diopter, the fourth lens has positive diopter, and the fifth lens has negative diopter. The fifth lens has a negative diopter, and an object side surface and an image side surface of the fifth lens have circular asymmetric shapes.

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 of camera devices in mobile terminals is also increasing. In order to improve the performance of camera devices, higher performance optical systems and image sensors are required. However, due to the narrow space of mobile terminals, high performance of optical systems and image sensors is not easy to achieve.

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

[0004] Technical issues

[0005] The technical problem to be solved by the present disclosure is to obtain a camera module that has a small F number, a large field of view, and a high relative illumination while achieving a small size.

[0006] The problem to be solved by this embodiment is not limited thereto, and it can be said that it also includes the purpose or effect that can be understood from the solution to achieve the problem described below or the specific content of the invention.

[0007] Technical Solution

[0008] An optical system according to an embodiment of the present disclosure includes an aperture, a first lens, a second lens, a third lens, a fourth lens, and a fifth lens, which are arranged in sequence from an object side to an image side, wherein the first lens has positive refractive power, the second lens has negative refractive power, the third lens has positive refractive power, the fourth lens has positive refractive power, the fifth lens has negative refractive power, and an object side surface and an image side surface of the fifth lens both have a circular asymmetric shape.

[0009] An entrance pupil diameter (EPD) may be greater than or equal to an effective diameter of an object-side surface of the first lens.

[0010] When the aperture is closed, the shortest distance between the aperture and the object-side surface of the first lens may be 0.2 mm or less.

[0011] The distance between the image-side surface of the first lens and the object-side surface of the second lens, and the distance between the image-side surface of the second lens and the object-side surface of the third lens may be smaller than the distance between the image-side surface of the third lens and the object-side surface of the fourth lens, and the maximum effective diameters among the object-side surface and the image-side surface of the first lens, the object-side surface and the image-side surface of the second lens, and the object-side surface and the image-side surface of the third lens may be smaller than the object-side surface and the image-side surface of the fourth lens, and the minimum effective diameters among the object-side surface and the image-side surface of the fifth lens.

[0012] The largest effective diameter among the object-side surface and the image-side surface of the first lens, the object-side surface and the image-side surface of the second lens, and the object-side surface and the image-side surface of the third lens may be 0.7 times or less the effective diameter of the image-side surface of the fifth lens.

[0013] The first lens, the second lens, the third lens, and the fourth lens may be circularly symmetric lenses.

[0014] At least one of the object-side surface and the image-side surface of the first lens, the object-side surface and the image-side surface of the second lens, and the object-side surface and the image-side surface of the third lens may include a critical point where the tilt angle is 0.

[0015] At least two of the object-side surface of the fourth lens, the image-side surface of the fourth lens, and the object-side surface of the fifth lens may not include a critical point, the object-side surface of the fourth lens may be concave toward the object side, the image-side surface of the fourth lens may be convex toward the image side, and the object-side surface of the fifth lens may be concave toward the object side.

[0016] An absolute value of a radius of curvature of an image-side surface of the fourth lens may be 0.9 to 1.1 times an absolute value of a radius of curvature of an object-side surface of the fifth lens.

[0017] At the same distance from the optical axis, a sag value of the object-side surface of the fifth lens in a first direction and a sag value in a second direction perpendicular to the first direction may be different from each other, and at the same distance from the optical axis, a sag value of the image-side surface of the fifth lens in the first direction and a sag value in the second direction may be different from each other.

[0018] At the same distance from the optical axis, a sag value of the object-side surface of the fifth lens in the first direction or a sag value in the second direction may be different from a sag value in a third direction between the first direction and the second direction.

[0019] At the same distance from the optical axis, the deviation between the sag value of the object-side surface of the fifth lens in the first direction or the sag value in the second direction and the sag value in the third direction may be greater than the deviation between the sag value of the object-side surface of the fifth lens in the first direction and the sag value in the second direction.

[0020] At the same distance from the optical axis, the deviation between the sag value of the image side surface of the fifth lens in the first direction and the sag value in the second direction may be greater than the deviation between the sag value of the object side surface of the fifth lens in the first direction and the sag value in the second direction.

[0021] A deviation between the maximum sag value in the first direction and the maximum sag value in the second direction of the image-side surface of the fifth lens may be more than 10 times a deviation between the maximum sag value in the first direction and the maximum sag value in the second direction of the object-side surface of the fifth lens.

[0022] The image-side surface of the fifth lens may include a critical point where an inclination angle is 0.

[0023] A maximum inclination angle from a critical point of the image-side surface of the fifth lens to an edge of the image-side surface of the fifth lens may be 5 to 7 times a maximum inclination angle from the optical axis to the critical point of the image-side surface of the fifth lens.

[0024] The maximum inclination angle may be 65 degrees or less within a range of 60% to 90% of the effective diameter of the image-side surface of the fifth lens.

[0025] The F number may be 2.45 or less, the field of view (FOV) may be 80 degrees or more, and the relative illumination (RI) may be 40% or more.

[0026] A camera device according to an embodiment of the present disclosure includes an image sensor, a filter disposed on the image sensor, and an optical system disposed on the filter, wherein the optical system includes an aperture, a first lens, a second lens, a third lens, a fourth lens, and a fifth lens disposed in sequence from an object side to an image side, wherein the first lens has a positive refractive power, the second lens has a negative refractive power, the third lens has a positive refractive power, the fourth lens has a positive refractive power, the fifth lens has a negative refractive power, and an object side surface and an image side surface of the fifth lens both have a circular asymmetric shape.

[0027] Beneficial Effects

[0028] According to the embodiments of the present disclosure, a camera device having a small F number, a large field of view (FOV), and a high relative illumination (RI) while achieving a small size can be obtained.

[0029] According to the embodiments of the present disclosure, a camera device having an F number of 2.45 or less, a FOV of 80 degrees or more, and a 1 field of view (marginal field of view) RI of 40% or more while achieving a small size can be obtained.

[0030] 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 (i.e., the lens disposed closest to the object side) to be small can be obtained. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 An optical system according to an embodiment of the present disclosure is shown.

[0032] Figure 2 The relationship between the first lens and the aperture of the optical system according to the embodiment of the present disclosure is shown.

[0033] Figure 3 and Figure 4 It is a view used to describe relative illumination.

[0034] Figure 5 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.

[0035] Figure 6 1 is design data showing sagittal values ​​of lens surfaces according to distances from the optical axis in the Y direction of first to fourth lenses of the optical system according to an embodiment of the present disclosure.

[0036] Figure 7 1 is design data showing the sagittal values ​​of the lens surface according to the distances from the optical axis in the X direction, the Y direction, the diagonal direction, and the 45-degree direction of the fifth lens of the optical system according to the embodiment of the present disclosure.

[0037] Figure 8 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.

[0038] Fig. 9 The modulation transfer function (MTF) of an optical system using one embodiment of the present disclosure is shown.

[0039] Fig.10 A distortion grid using an optical system according to one embodiment of the present disclosure is shown.

[0040] Fig.11 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, 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 unless explicitly specifically defined and described, 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 fields.

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

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

[0046] Furthermore, 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,” “coupled” or “linked” to another component, this may include not only a case where the component is directly connected, coupled or linked to another component, but also a case where the component is connected, coupled or linked to another component via another component between the component and the other component.

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

[0050] Figure 1 An optical system according to an embodiment of the present disclosure is shown.

[0051] Reference Figure 1 , the optical system 100 according to an embodiment of the present disclosure includes a first lens 110 , a second lens 120 , a third lens 130 , a fourth lens 140 and a fifth lens 150 which are sequentially arranged from an object side to an 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, and the fifth lens 150 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 where the incident light is refracted to achieve optical characteristics. In this 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 this specification, the value of the effective diameter may have a certain error range. For example, a range of ±0.4 mm may be regarded as an effective area of ​​the value of the effective diameter presented in this specification, and a range of ±0.4 mm may be interpreted as an effective diameter of the value of the effective diameter presented in this specification. The ineffective area is set at the periphery of the effective area, and may be an area on which light is not incident, that is, an area that is not related to optical characteristics. The ineffective area may be an area fixed to a lens barrel or the like that houses the lens.

[0054] According to an embodiment of the present disclosure, a filter 160 and an image sensor 170 may be sequentially disposed behind the fifth lens 150. In this case, the filter 160 may be an infrared (IR) filter. Thus, the filter 160 may block near infrared rays (e.g., light having a wavelength of 700nm to 1100nm) from being incident on the camera device. Alternatively, the filter 160 may be a filter that transmits IR, rather than a filter that blocks IR. In addition, the image sensor 170 may be connected to a printed circuit board.

[0055] 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 arranged in sequence along the optical axis. According to an embodiment of the present disclosure, the first lens 110, the second lens 120, the third lens 130 and the fourth lens 140 may be circular symmetrical lenses, and the fifth lens 150 may be a circular asymmetrical lens. The first lens 110, the second lens 120, the third lens 130, the fourth lens 140 and the fifth lens 150 may all be made of plastic or glass.

[0056] The first lens 110 has a 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 lens surface is convex may refer to that the surface of the lens in the area corresponding to the optical axis has a convex shape, and the case where the lens surface is concave may refer to that the surface of the lens in the area corresponding to the optical axis has a concave shape. Here, the area corresponding to the optical axis may refer to the optical axis area or the paraxial area. 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 convex 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 concave toward the image side.

[0059] The fourth lens 140 has positive 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 concave toward the object side, and the image-side surface 144 may be convex toward the image side.

[0060] The fifth lens 150 may have negative refractive power and include an object-side surface 152 and an image-side surface 154 , and the object-side surface 152 of the fifth lens 150 may be concave toward the object side, and the image-side surface 154 may be concave toward the image side.

[0061] 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 positive refractive power, and the fifth lens 150 has negative refractive power, chromatic aberration may be corrected.

[0062] Figure 2 The relationship between the first lens and the aperture in the optical system according to the embodiment of the present disclosure is shown.

[0063] Reference Figure 2, 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, and a fifth lens 150, which are disposed in sequence 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 a region corresponding to the optical axis OA 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 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 more preferably 0.01 mm or less. In the case that the aperture ST is not a drivable aperture, the shortest distance between the position of the aperture and the object-side surface 112 of the first lens 110 may be less than 0.2 mm.

[0064] According to an embodiment of the present disclosure, the entrance pupil diameter (EPD) of the optical system 100 may be greater than or equal to the effective diameter ED 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 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.

[0065] Refer again Figure 1 , the object-side surface 112 of the first lens 110 has the smallest effective diameter among the first lens 110, the second lens 120, the third lens 130, the fourth lens 140, and the fifth lens 150. For example, the effective diameter ED of the first lens 110 is L1S1 It can be 1.16mm to 1.96mm. According to an embodiment of the present disclosure, the effective diameter of the object-side surface 112 of the first lens 110 can be smaller than the length of the image sensor 170 in the diagonal direction. For example, the effective diameter of the object-side surface 112 of the first lens 110 can be less than 70% of the length of the image sensor 170 in the diagonal direction, preferably less than 50%, more preferably less than 40%, more preferably less than 30%. When the effective diameter ED of the first lens 110 L1S1When the length in the diagonal direction with the image sensor 170 satisfies this condition, a design can be made to minimize the head size of the optical system exposed to the outside. When the aperture ST is arranged 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 the 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 set on the 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 set below a display.

[0066] At the same time, since the effective diameter of the first lens 110 becomes smaller, the size of the head exposed to the outside can be minimized. However, since the effective diameter of the first lens 110 becomes smaller, the amount of light incident on the optical system 100 may be insufficient. Therefore, when designing an optical system including the first lens 110, it is necessary to consider the condition of brightening the image by reducing the F number and increasing the ratio of the amount of light incident on the periphery of the image sensor to the amount of light incident on the central portion of the image sensor, that is, the relative illumination (RI).

[0067] Here, the central portion of the image sensor refers to an area close to the 0 field of view (central field of view) of the image sensor, and the periphery of the image sensor refers to an area close to the 1 field of view of the image sensor.

[0068] Figure 3 and Figure 4 It is a view used to describe relative illumination.

[0069] Reference Figure 3 , it can be seen that the area where light can reach the image sensor depends on the incident angle of light incident from the object side. That is, the image sensor is divided into a 0 field of view area and a 1 field of view area, the 0 field of view area is the central part of the image sensor, and the 1 field of view area is the position farthest from the central part of the image sensor, and it can be seen that as the incident angle of light becomes larger, the light reaches the 1 field of view area (periphery) closer to the image sensor, and as the incident angle of light becomes smaller, the light reaches the 0 field of view area (center) closer.

[0070] Reference Figure 4, 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 an angle α relative to 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.

[0071] 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.

[0072] Tables 1 and 2 below show the optical properties of each lens included in the optical system according to an embodiment of the present disclosure, Table 3 shows the Qcon coefficients of the first to fourth lenses included in the optical system according to an embodiment of the present disclosure, and Table 4 shows the Zernike coefficient of the fifth lens included in the optical system according to an embodiment of the present disclosure.

[0073] [Table 1]

[0074]

[0075] [Table 2]

[0076]

[0077] [Table 3]

[0078]

[0079] [Table 4]

[0080] In Table 1, thickness (mm) refers to the distance from each lens surface to the next lens surface. For example, the thickness of the aperture ST refers to 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 when the aperture ST is closed. The thickness of the object-side surface 112 of the first lens 110 refers to the distance from the object-side surface 112 of the first lens 110 to the image-side surface 114. In Table 1, thickness (mm) may refer to the distance from the optical axis. For example, the thickness of the object-side surface 112 of the first lens 110 may refer to the distance between the center of curvature of the object-side surface 112 of the first lens 110 and the center of curvature of the image-side surface 114. The thickness of the image-side surface 114 of the first lens 110 refers to 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 thickness of the image-side surface 114 of the first lens 110 refers to 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.

[0081] In Tables 1 and 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 refer to 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 refer to 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.

[0082] The thickness of the object-side surface of the first to fourth lenses in Table 1, which are circularly symmetric lenses, may coincide with the center thickness of the first to fourth lenses in Table 2, and the thickness of the image-side surface of the first to third lenses in Table 1, which are circularly symmetric lenses, may coincide with the air gap of the first to third lenses in Table 2. However, since the object-side surface 152 and the image-side surface 154 of the fifth lens 150 have circular asymmetric shapes, there may be an offset. Therefore, the thickness of the image-side surface 144 of the fourth lens 140 shown in Table 1, that is, the distance between the image-side surface 144 of the fourth lens 140 and the object-side surface 152 of the fifth lens 150, may not coincide with the air gap of the fourth lens 140 shown in Table 2. Similarly, the thickness of the object-side surface 152 of the fifth lens 150 shown in Table 1 may not coincide with the center thickness of the fifth lens 150 shown in Table 2.

[0083] In the optical system 100 according to the embodiment of the present disclosure, the first lens 110 , the second lens 120 , and the third lens 130 may be referred to as a first lens group G1 , and the fourth lens 140 and the fifth lens 150 may be referred to as a second lens group G2 .

[0084] According to an embodiment of the present disclosure, the first lens 110 may have the largest center thickness among the first to fifth lenses. 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 sum of the center thickness CT1 of the first lens 110. According to an embodiment of the present disclosure, the center thickness CT1 of the first lens 110 may be greater than the center thickness CT4 of the fourth lens 140, and may be greater than the center thickness CT5 of the fifth lens 150.

[0085] The distance between the first lens group G1 and the second lens group G2 of the present disclosure, that is, 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, may be greater than the distance between adjacent lenses in the first lens group G1, for example, 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 or 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 first lens group G1 and the second lens group G2 of the present disclosure, that is, 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, may be greater than or equal to 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. Alternatively, the distance T34 between the first lens group G1 and the second lens group G2 of the present disclosure, that is, 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 may be 0.95 to 1.1 times, preferably, 0.97 to 1.05 times, and more preferably, 0.99 to 1.02 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. In addition, 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 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 may be smaller 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.

[0086] When at least one of the refractive power of the first to fifth 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 gather light and correct chromatic aberration, and the second lens group G2 can be used to evenly diffuse light to each peripheral pixel of the image sensor. That is, according to an embodiment of the present disclosure, in order to reduce the head size of the optical system 100, the effective diameter of the object side surface 112 of the first lens 110 is designed to be smaller than the image sensor 170. Specifically, the effective diameter of the object side surface 112 of the first lens 110 is designed to be smaller than the image sensor 170, and when the distance between the lenses in the first lens group G1 satisfies the above conditions, even if the effective diameter of the object side surface 112 of the first lens 110 is sufficiently small, light can be gathered without distortion. In addition, when the distance between the first lens group G and the second lens group G2 and the distance between the lenses in the second lens group G2 satisfy the above conditions, that is, when the distance between the lenses in the first lens group G1 is set farther, the light gathered 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.

[0087] According to an embodiment of the present disclosure, the first lens 110, the second lens 120, and the third lens 130 have positive compound refractive power, and the fourth lens 140 and the fifth lens 150 have negative compound refractive power. That is, the compound refractive power of the first lens 110, the second lens 120, and the third lens 130 may be 0.27, and the compound refractive power of the fourth lens 140 and the fifth lens 150 may be -0.2. Therefore, the first lens 110, the second lens 120, and the third lens 130 may be used to gather light incident on the object side surface of the first lens 110, and the fourth lens 140 and the fifth lens 150 may be used to diffuse 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 170.

[0088] Specifically, 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 absolute value P1 of the refractive power of the first lens 110 is more than 1.5 times the absolute value P2 of the refractive power of the second lens 120, and the center thickness CT1 of the first lens 110 is more than 2 times the center thickness CT2 of the second lens, the first lens 110 can gather light incident on the optical system 100, and the second lens 120 can correct chromatic aberration.

[0089] In addition, when the distance T34 between the first lens group G1 and the second lens group G2 among the distances between adjacent lenses in the optical system 100 is the largest, and the distance T45 between the fourth lens 140 and the fifth lens 150 in the second lens group G2 is greater than the distance T12 between the first lens 110 and the second lens 120 in the first lens group G1 and the distance T23 between the second lens 120 and the third lens 130 in the first lens group G1, the second lens group G2 can be used to diffuse light more uniformly to the periphery of the image sensor.

[0090] According to an embodiment of the present disclosure, the total track length (TTL) as the distance from the object side surface 112 of the first lens 110 to the image sensor 170 is 4 mm to 4.5 mm, preferably 4.35 mm, the distance from the object side surface 122 of the second lens 120 to the image sensor 170 is 3.5884 mm, the distance from the object side surface 132 of the third lens 130 to the image sensor 170 is 3.3084 mm, the distance from the object side surface 142 of the fourth lens 140 to the image sensor 170 is 2.2841 mm, and the distance from the object side surface 152 of the fifth lens 150 to the image sensor 170 is 1.136 mm. In addition, the back focal length (BFL) as the distance from the image side surface 154 of the fifth lens 150 to the image sensor 170 is 0.7287 mm. In addition, the diagonal length (2*H imageD ) is 6.53801mm. From the perspective of those skilled in the art, considering the assembly performance, 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.

[0091] According to an embodiment of the present disclosure, the maximum effective diameter of the lens included in the first lens group G1 may be greater than the minimum effective diameter of the lens included in the second lens group G2. Here, the effective diameter may refer to the diameter of an effective area of ​​the object side surface or the image side surface where light is incident.

[0092] In this case, the maximum effective diameter (ED G1_max ) may be larger than the minimum effective diameter (ED G1_minThe maximum effective diameter (ED) of the lenses included in the first lens group G1 is G1_max ) may be the minimum effective diameter (ED) of the lenses included in the first lens group G1. G1_min ) is 1 to 1.5 times of that in the first lens group G1. G1_min ) is the effective diameter of the object-side surface 112 of the first lens 110, so the effective diameters of 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, and the object-side surface 132 and the image-side surface 134 of the third lens 130 can be 1 to 1.5 times the effective diameter of the object-side surface 112 of the first lens 110.

[0093] In addition, the effective diameters of the fourth lens 140 and the fifth lens 150 may gradually increase from the object side to the image side. For example, the effective diameter (ED L4S2 ) may be larger than the effective diameter (ED L4S1 ), the effective diameter (ED L5S1 ) may be larger than the effective diameter (ED L4S2 ), the effective diameter (ED L5S2 ) may be larger than the effective diameter (ED L5S1 ).

[0094] In addition, the maximum effective diameter (ED G1_max ) may be an effective diameter (ED ) of the image-side surface 154 of the fifth lens 150 L5S2 ), preferably, 0.6 times or less, and more preferably, 0.5 times or less.

[0095] Therefore, the first lens group G1 is used to collect light incident on the optical system 100 and adjust the incident angle of light incident on the second lens group G2. In addition, the second lens group G2 can be used to diffuse light incident on the second lens group G2 after passing through the first lens group G1 to increase the amount of light reaching the periphery of the image sensor 170.

[0096] Figure 5 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 6 are design data showing sagittal values ​​of lens surfaces according to distances from the optical axis in the Y direction of first to fourth lenses of the optical system according to an embodiment of the present disclosure, Figure 7is design data showing the sagittal values ​​of the lens surface according to the distances from the optical axis in the X direction, the Y direction, the diagonal direction, and the 45-degree direction of the fifth lens of the optical system according to an embodiment of the present disclosure, Figure 8 ] is design data showing the tilt 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 5 to 8 , L1, L2, L3, L4 and L5 respectively represent the first lens 110, the second lens 120, the third lens 130, the fourth lens 140 and the fifth lens 150, and L1S1, L1S2, L2S1, L2S2, L3S1, L3S2, L4S1, L4S2, L5S1 and L5S2 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, and the object-side surface 152 and the image-side surface 154 of the fifth lens. The air gap 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, and the air gap between L4 and L5 represents the distance between the fourth lens 140 and the fifth lens 150.

[0097] Reference Figure 5 , 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 from the optical axis to the end of the lens surface between the opposite surfaces of different lenses to the minimum distance is 3 times or less, it can be interpreted that the distance between the opposite surfaces of different lenses is uniformly maintained.

[0098] 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 ) can be less than 3 times.

[0099] Similarly, the distance between the image-side surface 124 of the second lens 120 and the object-side surface 132 of the third lens 130 can be uniformly maintained from the optical axis to the end of the image-side surface 124 of the first lens 120. That is, the maximum distance (T23 ) 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 max ) and the minimum distance (T23 min ) can be less than 3 times.

[0100] Similarly, 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 θ) 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, more preferably, 1.5 times or less.

[0101] 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, more preferably, 1.3 times.

[0102] At the same time, refer to Figures 6 to 8 According to an embodiment of the present disclosure, at least one surface of at least one of the first to fifth lenses forming the optical system 100 includes a critical point. The critical point may refer to a point where the trend of the sag value changes. 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. The point where the trend of the sag value changes may be a point where the sag value increases and then decreases, or a point where the sag value decreases and then increases. The critical point may refer to a point where the tilt angle becomes 0. The tilt angle may be defined as the angle formed by the normal of the tangent line of the lens surface and the optical axis.

[0103] 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 efficiently refracted near the critical point. That is, light passing through a lens surface including a critical point can be more efficiently refracted than light passing through a lens surface not including a 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, and when the effective diameter of the object-side surface 112 of the first lens 110 is designed to be smaller to minimize the head size, or even when the maximum effective diameter in the first lens group G1 is designed to be smaller than the minimum effective diameter in the second lens group G2 to minimize the head size, light incident through the effective diameter of the object-side surface 112 of the first lens 110 can be refracted within the widest possible range between the first lens to the third lens, the light can uniformly reach the pixels in the periphery of the image sensor 170, and the performance of the optical system 100 can be enhanced.

[0104] In addition, according to an embodiment of the present disclosure, at least two of the object-side surface 142 and the image-side surface 144 of the fourth lens 140 and the object-side surface 152 of the fifth lens 150 do not include a critical point, and the image-side surface 154 of the fifth lens 150 may include a critical point. According to an embodiment of the present disclosure, the object-side surface 142 and the image-side surface 144 of the fourth lens 140 and the object-side surface 152 of the fifth lens 150 may not include a critical point, and the image-side surface 154 of the fifth lens 150 may include a critical point. Light is more effectively refracted near the critical point. When a critical point exists on the periphery of the image-side surface 154 of the fifth lens 150 that is closest to the lens surface of the image sensor 170, light refracted at the periphery of the image-side surface 154 of the fifth lens 150 easily and uniformly reaches pixels at the periphery of the image sensor 170. The periphery 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 154 of the fifth lens 150 which is the lens surface closest to the image sensor 170, the assembly performance 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 the lens surface farthest from the image sensor 170. Even when the fifth lens 150 is slightly tilted during assembly, since the assembly of the first to fourth lenses of the optical system 100 is not affected and thus the optical performance is not significantly affected, the assembly performance of the optical system 100 can be improved. When a critical point exists on the image-side surface or the object-side surface of the first lens 110 which is the lens surface farthest from the image sensor 170 and the first lens is tilted during assembly and assembled, since the tilt of the assembly affects the second lens and the fifth lens which are the remaining lenses, the performance of the optical system is significantly reduced.

[0105] 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 at a vertical distance of 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 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 about 50% to 60%. 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.

[0106] 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 at a vertical distance of 0.8 mm to 0.9 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 about 80% to 90%.

[0107] 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 at a vertical distance of 0.6 mm to 0.7 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 about 60% to 70%.

[0108] 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 at a vertical distance of 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 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 about 70% to 80%.

[0109] Therefore, when a critical point exists on at least one of the six surfaces of the first lens to the third lens included in the first lens group G1, light can be uniformly diffused in the first lens group G1, output through the image-side surface 134 of the third lens 130 of the first lens group G1, and incident on the object-side surface 142 of the fourth lens 140.

[0110] 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 do not include a critical point, and the object-side surface 142 of the fourth lens 140 is concave toward the object side, the image-side surface 144 of the fourth lens 140 is convex toward the image side, and the object-side surface 152 of the fifth lens 150 is concave toward the object side. In addition, the curvature radius (R L4S2 ) may be the absolute value of the curvature radius (R L5S1 ), preferably, 0.95 to 1.05 times the absolute value 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 meet the above conditions, light that is uniformly diffused in the first lens group G1 and incident on the object-side surface 142 of the fourth lens 140 after exiting through the image-side surface 134 of the third lens 130 of the first lens group G1 can be uniformly diffused and incident on the object-side surface 142 of the fifth lens 150 from the center to the periphery.

[0111] According to an embodiment of the present disclosure, the first to fourth lenses are circularly symmetrical lenses, and the fifth lens 150 is a lens having both sides in a circular asymmetrical shape.

[0112] Reference Figure 7, the object-side surface 152 and the image-side surface 154 of the fifth lens 150 both have a circular asymmetric shape. When the object-side surface 152 and the image-side surface 154 of the fifth lens 150 are both circular asymmetric shapes, it is possible to minimize optical distortion, achieve an optical angle, and increase RI while reducing the total number of lenses included in the optical system 100. The circular asymmetric shape may refer to a shape of a lens cross section that is different in the X-axis and Y-axis directions around the optical axis, a shape of a lens cross section that is different in the third direction between the X-axis and the Y-axis from that in the X-axis direction, or a shape of a lens cross section that is different in the third direction between the X-axis and the Y-axis from that in the Y-axis direction. Here, the third direction may refer to a diagonal direction of an 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 of the image sensor is different from the Y-axis length, for example, when the ratio of the X-axis length to the Y-axis length of the image sensor is 4:3, 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 tilt angles, different sag values, or different points where the critical point appears when there is a critical point. For example, the different shapes in the X-axis direction and the Y-axis direction may refer to a region where the tilt angle in the X-axis direction and the tilt 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 the distance between the optical axis in the X-axis direction and the critical point and the distance between the optical axis in the Y-axis direction and the critical point are different from each other. Circular asymmetric shapes may be used interchangeably with free surface shapes, autonomous surface shapes, rotationally asymmetric shapes, free form shapes, origin asymmetry, etc.

[0113] According to an embodiment of the present disclosure, on the object-side surface 152 of the fifth lens, there is a deviation between the sagittal value in the X direction and the sagittal value in the Y direction. As described above, the sagittal value refers to the distance on the optical axis between any point on the lens surface and a point on the optical axis. Figure 7 In the figure, a positive sag value refers to a shape protruding to the right from the optical axis, and a negative sag value refers to a shape protruding to the left from the optical axis. It is obvious to those skilled in the art that the signs of the sag values ​​can be defined in the opposite way. For example, a negative sag value can also refer to a shape protruding to the right from the optical axis, and a positive sag value can also refer to a shape protruding to the left from the optical axis. For example, the sag value (Sag) of the object-side surface 152 of the fifth lens 150 in the X direction is L5S1_X ) and the sag value in the Y direction (Sag L5S1_Y) may be 0.001 μm to 20 μm. For example, the sag value (Sag L5S1_X ) and the sag value in the Y direction (Sag L5S1_Y ) tends to increase as it moves away from the optical axis. For example, in a region where the vertical distance from the optical axis is less than 1 mm, the sag value (Sag L5S1_X ) and the sag value in the Y direction (Sag L5S1_Y ) may be 5 μm, preferably, 3 μm or less, more preferably, 2 μm or less. In a region where the vertical distance from the optical axis exceeds 1 mm, the sag value (Sag L5S1_X ) and the sag value in the Y direction (Sag L5S1_Y ) may have a deviation of 2 μm to 20 μm, preferably, 3 μm to 20 μm, more preferably, 5 μm to 20 μm.

[0114] Therefore, light passing through the object-side surface 152 of the fifth lens 150 may be more uniformly diffused and reach pixels at the periphery of the image sensor 170 .

[0115] According to an embodiment of the present disclosure, the sag value (Sag L5S1_X ) or the sag value in the Y direction (Sag L5S1_Y ) and the sag value in the diagonal direction (Sag L5S1_D ) may have a deviation on the object-side surface 152 of the fifth lens 150. Here, the diagonal direction may refer to a diagonal direction between the X direction and the Y direction based on the image sensor. For example, when the ratio of the X direction to the Y direction of the image sensor is 1:1, the diagonal direction may refer to a direction in which an angle of 45 degrees is formed between the X direction and the Y direction. Conversely, when the ratio of the X direction to the Y direction of the image sensor is 3:4 or 4:3, the diagonal direction may be different from the direction in which an angle of 45 degrees is formed between the X direction and the Y direction. For example, the sag value (Sag L5S1_X ) or the sag value in the Y direction (Sag L5S1_Y ) and the sag value in the diagonal direction (Sag L5S1_D ) may be 0.001 μm to 100 μm. For example, the sag value (Sag L5S1_X ) or the sag value in the Y direction (Sag L5S1_Y ) and the sag value in the diagonal direction (Sag L5S1_D) tends to increase as it moves away from the optical axis. Therefore, light passing through the object-side surface 152 of the fifth lens 150 can be more uniformly diffused and reach pixels at the periphery of the image sensor 170.

[0116] According to an embodiment of the present disclosure, based on the same distance from the optical axis, the sag value (Sag L5S1_X ) or the sag value in the Y direction (Sag L5S1_Y ) and the sag value in the diagonal direction (Sag L5S1_D ) may be greater than the sag value (Sag L5S1_X ) and the sag value in the Y direction (Sag L5S1_Y ). Therefore, light passing through the object-side surface 152 of the fifth lens 150 may be more uniformly diffused and reach pixels at the periphery of the image sensor 170.

[0117] According to an embodiment of the present disclosure, the sag value (Sag L5S2_X ) and the sag value in the Y direction (Sag L5S2_Y ) may have a deviation on the image-side surface 154 of the fifth lens 150. For example, the sag value (Sag L5S2_X ) and the sag value in the Y direction (Sag L5S2_Y ) may be 0.001 μm to 500 μm. For example, the sag value (Sag L5S2_X ) and the sag value in the Y direction (Sag L5S2_Y ) tends to increase as it moves away from the optical axis. For example, in a region where the vertical distance from the optical axis is less than 1 mm, the sag value (Sag L5S2_X ) and the sag value in the Y direction (Sag L5S2_Y ) may be less than 1 μm. In a region where the vertical distance from the optical axis exceeds 1 mm, the sag value (Sag L5S2_X ) and the sag value in the Y direction (Sag L5S2_Y) may be 1 μm to 500 μm, preferably 1 μm to 400 μm, and more preferably 1 μm to 350 μm. Therefore, light passing through the image-side surface 154 of the fifth lens 150 may be more uniformly diffused and reach pixels at the periphery of the image sensor 170. In addition, when at least one of the object-side surface 152 and the image-side surface 154 of the fifth lens 150 includes a circular asymmetric shape, since the effect of arranging a plurality of lenses in an overlapping manner can be obtained using a single lens, the optical performance can be improved while realizing a small-sized optical system 100.

[0118] According to an embodiment of the present disclosure, the sag value (Sag L5S2_X ) or the sag value in the Y direction (Sag L5S2_Y ) and the sag value in the diagonal direction (Sag L5S2_D ) may have a deviation on the image-side surface 154 of the fifth lens 150. Therefore, light passing through the image-side surface 154 of the fifth lens 150 may be more uniformly diffused and reach pixels at the periphery of the image sensor 170.

[0119] According to an embodiment of the present disclosure, based on the same distance from the optical axis, the sag value (Sag L5S2_X ) and the sag value in the Y direction (Sag L5S2_Y ) may be greater than the sag value (Sag L5S1_X ) and the sag value in the Y direction (Sag L5S1_Y ). Therefore, since the effect of arranging a plurality of lenses in an overlapping manner can be obtained using a single lens, the optical performance can be improved while realizing the optical system 100 in a small size.

[0120] According to an embodiment of the present disclosure, the maximum sag value (max_Sag L5S1_X ) and the maximum sag value in the Y direction (max_Sag L5S1_Y ) may be different, and the maximum sag value (max_Sag L5S1_X ) and the maximum sag value in the Y direction (max_Sag L5S1_Y ) can be different. Here, the maximum sag value in the X direction (max_Sag L5S1_X ) refers to the maximum sag value among the sag values ​​obtained from the optical axis along the X direction, and the maximum sag value in the Y direction (max_Sag L5S1_Y ) refers to the maximum sag value among the sag values ​​obtained along the Y direction from the optical axis.

[0121] According to an embodiment of the present disclosure, the maximum sag value (max_Sag L5S1_X ) or the maximum sag value in the Y direction (max_Sag L5S1_Y ) can be different from the maximum sag value in the diagonal direction (max_Sag L5S1_D ).

[0122] According to an embodiment of the present disclosure, the maximum sag value (max_Sag L5S1_X ) or the maximum sag value in the Y direction (max_Sag L5S1_Y ) and the maximum sag value in the diagonal direction (max_Sag L5S1_D ) may be greater than the maximum sag value (max_Sag L5S1_X ) and the maximum sag value in the Y direction (max_Sag L5S1_Y ) between them.

[0123] According to an embodiment of the present disclosure, the maximum sag value (max_Sag L5S2_X ) and the maximum sag value in the Y direction (max_Sag L5S2_Y ) may be greater than the maximum sag value (max_Sag L5S1_X ) and the maximum sag value in the Y direction (max_Sag L5S1_Y For example, the maximum sag value (max_Sag) of the image side surface 154 of the fifth lens 150 in the X direction L5S2_X ) and the maximum sag value in the Y direction (max_Sag L5S2_Y ) may be the maximum sag value (max_Sag L5S1_X ) and the maximum sag value in the Y direction (max_Sag L5S1_Y ) is more than 10 times the deviation between them. Therefore, since the effect of arranging a plurality of lenses in an overlapping manner can be obtained using a single lens, the optical performance can be improved while realizing the optical system 100 in a small size.

[0124] Therefore, when both the object-side surface 152 and the image-side surface 154 of the fifth lens 150 have a circular asymmetric shape, distortion of light passing through the fifth lens 150 can be minimized, and the light passing through the fifth lens 150 can be uniformly diffused. Therefore, since the effect of arranging a plurality of lenses in an overlapping manner can be obtained using a single lens, optical performance can be improved while implementing the optical system 100 in a small size.

[0125] According to an embodiment of the present disclosure, the critical point of the image-side surface 152 of the fifth lens 150 may be a point at a vertical distance of 0.9 mm to 1 mm from the optical axis. According to an embodiment of the present disclosure, the critical point of the image-side surface 154 of the fifth lens 150 may be set in an area at a vertical distance of less than 1 mm from the optical axis, that is, the sag value (Sag L5S1_X ) and the sag value in the Y direction (Sag L5S1_Y ) is less than 1 μm. Therefore, the dispersion characteristics of light passing through the image-side surface 154 of the fifth lens 150 can be maximized.

[0126] Reference Figure 8 According to an embodiment of the present disclosure, a maximum tilt angle from the optical axis to a critical point of the image-side surface 154 of the fifth lens 150 may be greater than a maximum tilt angle from the critical point to an edge of the image-side surface 154 of the fifth lens 150. For example, the maximum tilt angle from the optical axis to the critical point of the image-side surface 154 of the fifth lens 150 may be 5 to 7 times the maximum tilt angle from the critical point to the edge of the image-side surface 154 of the fifth lens 150. In this case, the maximum tilt angle may be 65 degrees or less within a range of 60% to 90% of the effective diameter of the image-side surface 154 of the fifth lens 150. Therefore, manufacturing performance may be improved while satisfying optical performance.

[0127] Therefore, the dispersion characteristic of light passing through the image-side surface 154 of the fifth lens 150 can be maximized, and the RI can be improved.

[0128] The optical system 100 according to the embodiment of the present disclosure may satisfy at least one of the conditional expressions described below. Therefore, the optical system 100 according to the embodiment of the present disclosure may have an optical enhancement effect. Specifically, the optical system 100 according to the embodiment of the present disclosure may be at half the diagonal length (H imageD ) is 3.2690mm, and the optical performance is obtained such that the effective focal length (EFL) is 3.76mm, the F number is less than 2.45, the FOV in the diagonal direction is more than 80 degrees, and the RI of 1 field of view is more than 40%.

[0129] [Formula 1]

[0130] ED L1S1 ≤EPD

[0131] Here, ED L1S1 is the effective diameter of the object-side surface 112 of the first lens 110, and the entrance pupil diameter (EPD) is the diameter of the entrance pupil. 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.

[0132] [Formula 2-1]

[0133] ED L1S1 <0.3*2H imageD

[0134] [Formula 2-2]

[0135] ED L1S1 <0.5*2H imageD

[0136] [Formula 2-3]

[0137] ED L1S1 <0.7*2H imageD

[0138] Here, H imageD is a half value of the diagonal length of the pixel area of ​​the image sensor 170. According to [Formula 2-1] to [Formula 2-3], since the area of ​​the object-side surface 112 of the first lens 110 exposed to the outside can be minimized within the range of manufacturing the first lens 110, the head size of the optical system 100 can be minimized.

[0139] [Formula 3-1]

[0140] 3mm≤TTL≤6.5mm

[0141] [Formula 3-2]

[0142] 3mm≤TTL≤5.5mm

[0143] [Formula 3-3]

[0144] 4mm≤TTL≤4.5mm

[0145] Here, TTL is the distance from the object-side surface 112 of the first lens 110 to the image sensor 170. When TTL is less than the lower limit of [Formula 3-1] to [Formula 3-3], manufacturability is poor and it may be difficult to achieve a preferred effective focal length, and when TTL exceeds the upper limit of [Formula 3-1] to [Formula 3-3], the size of the camera device increases, and thus it may be difficult to implement the camera device in a compact size in a mobile terminal.

[0146] [Formula 4-1]

[0147] 0.9≤TTL / EFL≤1.4

[0148] [Formula 4-2]

[0149] 1.0≤TTL / EFL≤1.3

[0150] [Formula 4-3]

[0151] 1.06≤TTL / EFL≤1.2

[0152] Here, EFL is the effective focal length. According to [Formula 4-1] to [Formula 4-3], a high-resolution image can be obtained even in a narrow space.

[0153] [Formula 5-1]

[0154] 0.5≤TTL / 2*H imageD ≤0.9

[0155] [Formula 5-2]

[0156] 0.55≤TTL / 2*H imageD ≤0.8

[0157] [Formula 5-3]

[0158] 0.61≤TTL / 2*H imageD ≤0.69

[0159] According to [Formula 5-1] to [Formula 5-3], a high-resolution image can be obtained even in a narrow space.

[0160] [Formula 6]

[0161] 2.56≤TTL / EPD≤2.89

[0162] Therefore, the head size of the optical system 100 and the overall size of the camera device can be miniaturized.

[0163] [Formula 7]

[0164] 1.46≤ED L1S1 ≤1.96

[0165] Therefore, the head size of the optical system 100 can be miniaturized.

[0166] [Formula 8]

[0167] CT1>CT2+CT3

[0168] 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, the first lens group G1 can condense light without distortion, and the first lens group G1 can be used to condense light and correct chromatic aberration.

[0169] [Formula 9]

[0170] 2≤CT1 / CT2

[0171] Therefore, even when the effective diameter of the object-side surface 112 of the first lens 110 is sufficiently small, the first lens group G1 may condense light without distortion, and the first lens group G1 may function to condense light and correct chromatic aberration.

[0172] [Formula 10]

[0173] CT1>CT4

[0174] Here, CT4 is the center thickness of the fourth lens 140 .

[0175] Therefore, even when the effective diameter of the object-side surface 112 of the first lens 110 is sufficiently small, the first lens group G1 can condense light without distortion, and the second lens group G2 can be used to uniformly diffuse light to each peripheral pixel of the image sensor.

[0176] [Formula 11]

[0177] CT1>CT5

[0178] 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, the first lens group G1 can condense light without distortion, and the second lens group G2 can be used to uniformly diffuse light to each peripheral pixel of the image sensor.

[0179] [Formula 12]

[0180] T34>T12

[0181] Here, T34 is the distance between the third lens 130 and the fourth lens 140, and T12 is the distance between the first lens 110 and the second lens 120. Therefore, even when the effective diameter of the object-side surface 112 of the first lens 110 is sufficiently small, light can be condensed without distortion, and the light condensed by the first lens group G1 can pass through the second lens group G2 and uniformly reach each pixel of the image sensor 170 without distortion.

[0182] [Formula 13]

[0183] T34>T23

[0184] Here, T34 is the distance between the third lens 130 and the fourth lens 140, and T23 is the distance between the second lens 120 and 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 condensed without distortion, and the light condensed by the first lens group G1 can pass through the second lens group G2 and uniformly reach each pixel of the image sensor 170 without distortion.

[0185] [Formula 14]

[0186] T45≤T34

[0187] Here, T34 is the distance between the third lens 130 and the fourth lens 140, and T45 is the distance between the fourth lens 140 and the fifth lens 150. Therefore, light condensed by the first lens group G1 may pass through the second lens group G2 and uniformly reach each pixel of the image sensor 170 without distortion.

[0188] [Formula 15-1]

[0189] 0.75≤T34 / T45≤1.3

[0190] [Formula 15-2]

[0191] 0.85≤T34 / T45≤1.2

[0192] [Formula 15-3]

[0193] 0.95≤T34 / T45≤1.1

[0194] According to [Formula 15-1] to [Formula 15-3], light condensed by the first lens group G1 may pass through the second lens group G2 and uniformly reach each pixel of the image sensor 170 without distortion.

[0195] [Formula 16]

[0196] T45>T12

[0197] Therefore, the first lens group G1 may be used to condense light and correct chromatic aberration, and the second lens group G2 may be used to uniformly diffuse light to each peripheral pixel of the image sensor.

[0198] [Formula 17]

[0199] T45>T23

[0200] Therefore, the first lens group G1 may be used to condense light and correct chromatic aberration, and the second lens group G2 may be used to uniformly diffuse light to each peripheral pixel of the image sensor.

[0201] [Formula 18]

[0202] 1.5≤|P1| / |P2|

[0203] 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. Preferably, |P1| / |P2| may be greater than 1.6.

[0204] [Formula 19]

[0205] 1≤ED G1_max / ED G1_min ≤1.5

[0206] Here, ED G1_max is the maximum effective diameter of the first lens group, ED G1_min is the minimum effective diameter in the first lens group. Therefore, the first lens group G1 can be used to collect light incident on the optical system 100. Preferably, ED G1_max / ED G1_min It may be 1 or more and 1.35 or less.

[0207] [Formula 20]

[0208] ED L4S1 <ED L4S2 <ED L5S1 <ED L5S2

[0209] Here, ED L4S1 is the effective diameter of the object-side surface 142 of the fourth lens 140, ED L4S2 is the effective diameter of the image-side surface 144 of the fourth lens 140, ED L5S1 is the effective diameter of the object-side surface 152 of the fifth lens 150, ED L5S2 is an effective diameter of the image-side surface 154 of the fifth lens 120. Therefore, the second lens group G2 may be used to diffuse light incident on the second lens group G2 after passing through the first lens group G1 to increase the amount of light reaching the periphery of the image sensor 170.

[0210] [Formula 21]

[0211] ED G1_max / ED L5S2 ≤0.7

[0212] Here, ED G1_max is the maximum effective diameter of the first lens group, ED L5S2is the effective diameter of the image-side surface 154 of the fifth lens 150. Therefore, the first lens group G1 can be used to collect light incident on the optical system 100 and adjust the incident angle of light incident on the second lens group G2. In addition, the second lens group G2 can be used to diffuse light incident on the second lens group G2 after passing through the first lens group G1 to increase the amount of light reaching the periphery of the image sensor 170.

[0213] [Formula 22]

[0214] T12 max / T12 min ≤3

[0215] 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 min is 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.

[0216] [Formula 23]

[0217] T23 max / T23 min ≤3

[0218] 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 can reach the object-side surface 132 of the third lens 130 from the image-side surface 124 of the second lens 120 in a concentrated state without being diffused.

[0219] [Equation 24]

[0220] T34 max / T34 min ≤3

[0221] 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 diffused.

[0222] [Formula 25]

[0223] T45 max / T45 min ≤3

[0224] 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 diffused. Preferably, T45 max / T45 min It can be less than 2.

[0225] [Equation 26]

[0226] 0.9≤|R L4S2 / R L5S1 |≤1.1

[0227] Here, R L4S2 is the radius of curvature of the image-side surface 144 of the fourth lens 140, R L5S1 is the curvature radius of the object-side surface 152 of the fifth lens 150. Therefore, light uniformly diffused in the first lens group G1 and incident on the object-side surface 142 of the fourth lens 140 after exiting through the image-side surface 134 of the third lens 130 of the first lens group G1 can be uniformly diffused and can then be incident on the image sensor from the center to the periphery of the object-side surface 152 of the fifth lens 150. Preferably, |R L4S2 / R L5S1 | can be greater than 0.95 and less than 1.05.

[0228] [Formula 27]

[0229] 0.001μm≤|Sag L5S1_X -Sag L5S1_Y |≤20μm

[0230] Here, Sag L5S1_X is the sag value of the object-side surface 152 of the fifth lens 150 in the X direction, Sag L5S1_Y is the sag value of the object-side surface 152 of the fifth lens 150 in the Y direction. Therefore, the light passing through the object-side surface 152 of the fifth lens 150 may be more uniformly diffused and reach the pixels at the periphery of the image sensor 170.

[0231] [Equation 28]

[0232] 0.001μm≤|SagL5S1_X -Sag L5S1_D |≤100μm

[0233] Here, Sag L5S1_D is a sag value in a diagonal direction of the object-side surface 152 of the fifth lens 150. Therefore, light passing through the object-side surface 152 of the fifth lens 150 may be more uniformly diffused and reach pixels at the periphery of the image sensor 170.

[0234] [Equation 29]

[0235] 0.001μm≤|Sag L5S1_Y -Sag L5S1_D |≤100μm

[0236] Therefore, light passing through the object-side surface 152 of the fifth lens 150 may be more uniformly diffused and reach pixels at the periphery of the image sensor 170 .

[0237] [Formula 30]

[0238] |Sag L5S1_X -Sag L5S1_Y |<|Sag L5S1_X -Sag L5S1_D |

[0239] Therefore, light passing through the object-side surface 152 of the fifth lens 150 can be more uniformly diffused and reach pixels at the periphery of the image sensor 170. In addition, since the effect of arranging a plurality of lenses in an overlapping manner can be obtained using a single fifth lens 150, optical performance can be improved while realizing a small-sized optical system 100.

[0240] [Equation 31]

[0241] |Sag L5S1_X -Sag L5S1_Y |<|Sag L5S1_Y -Sag L5S1_D |

[0242] Therefore, light passing through the object-side surface 152 of the fifth lens 150 can be more uniformly diffused and reach pixels at the periphery of the image sensor 170. In addition, since the effect of arranging a plurality of lenses in an overlapping manner can be obtained using a single fifth lens 150, optical performance can be improved while realizing a small-sized optical system 100.

[0243] [Formula 32]

[0244] 0.001μm≤|Sag L5S2_X -Sag L5S2_Y |≤500μm

[0245] Here, Sag L5S2_X is the sag value of the image side surface 154 of the fifth lens 150 in the X direction, Sag L5S2_Y is the sag value of the image side surface 154 of the fifth lens 150 in the Y direction. Therefore, the light passing through the object side surface 152 of the fifth lens 150 can be more evenly diffused and reach the pixels at the periphery of the image sensor 170. In addition, since the effect of arranging a plurality of lenses in an overlapping manner can be obtained using a single fifth lens 150, the optical performance can be improved while realizing a small-sized optical system 100. Preferably, |Sag L5S2_X -Sag L5S2_Y |It can be greater than or equal to 0.001 μm and less than or equal to 400 μm.

[0246] [Formula 33]

[0247] |Sag L5S1_X -Sag L5S1_Y |<|Sag L5S2_X -Sag L5S2_Y |

[0248] Therefore, since the effect of arranging a plurality of lenses in an overlapping manner can be obtained using a single lens, optical performance can be improved while realizing the optical system 100 in a small size.

[0249] [Equation 34]

[0250] |max _ Sag L5S1_X -max _ Sag L5S1_Y |<|max _ Sag L5S1_X -max _ Sag L5S1_D |

[0251] Here, max_Sag L5S1_X is the maximum sag value of the object-side surface 152 of the fifth lens 150 in the X direction, max_Sag L5S1_Y is the maximum sag value of the object side surface 152 of the fifth lens 150 in the Y direction, max_Sag L5S1_D is the maximum sag value in the diagonal direction of the object-side surface 152 of the fifth lens 150. Therefore, since the effect of arranging a plurality of lenses 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.

[0252] [Formula 35]

[0253] |max _ Sag L5S1_X -max _Sag L5S1_Y |<|max _ Sag L5S1_Y -max _ Sag L5S1_D |

[0254] Therefore, since the effect of arranging a plurality of lenses in an overlapping manner can be obtained using a single lens, optical performance can be improved while realizing the optical system 100 in a small size.

[0255] [Equation 36]

[0256] |max _ Sag L5S1_X -max _ Sag L5S1_Y |<|max _ Sag L5S2_X -max _ Sag L5S2_Y |

[0257] Here, max_Sag L5S2_X is the maximum sag value of the image-side surface 154 of the fifth lens 150 in the X direction, max_Sag L5S2_Y is the maximum sag value of the image-side surface 154 of the fifth lens 150 in the Y direction.

[0258] Therefore, distortion of light passing through the fifth lens 150 can be minimized, and light passing through the fifth lens 150 can be uniformly diffused. Therefore, since an effect of arranging a plurality of lenses in an overlapping manner can be obtained using a single lens, optical performance can be improved while implementing the optical system 100 in a small size.

[0259] [Formula 37]

[0260] 10<|max _ Sag L5S2_X -max _ Sag L5S2_Y | / |max _ Sag L5S1_X -max _ Sag L5S1_Y |

[0261] Therefore, distortion of light passing through the fifth lens 150 can be minimized, and light passing through the fifth lens 150 can be uniformly diffused. Therefore, since an effect of arranging a plurality of lenses in an overlapping manner can be obtained using a single lens, optical performance can be improved while implementing the optical system 100 in a small size.

[0262] Table 5 shows chief ray angle (CRA) data and RI values ​​according to the field of view that can be obtained using the optical system according to an embodiment of the present disclosure, Fig. 9 shows the modulation transfer function (MTF) of an optical system using an embodiment of the present disclosure, Fig.10 A distortion grid using an optical system according to one embodiment of the present disclosure is shown.

[0263] [Table 5]

[0264] Field of view CRA RI(%) 0 0 100.0％ 0.1 8.07145 99.1％ 0.2 15.5753 95.0％ 0.3 22.0528 87.3％ 0.4 27.1254 78.9％ 0.5 30.7006 70.8％ 0.6 33.1788 62.2％ 0.7 35.0345 53.7％ 0.8 36.3318 47.0％ 0.9 36.6351 43.3％ 1 35.5571 40.7％

[0265] 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 8 degrees or more (for example, in the range of 8 degrees to 37 degrees), and the light amount of the central part (0 field of view) of the image sensor is 100%, the light amount of the periphery (1 field of view) of the image sensor other than the 0 field of view is 40% or more. Fig. 9 , the clarity of an image according to the spatial frequency of a pixel that can be obtained from the optical system according to one embodiment of the present disclosure can be obtained, and referring to Fig.10 , 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.

[0266] Fig.11 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.

[0267] Meanwhile, 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 into 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 smartphone, a tablet computer (PC), a laptop computer, a personal digital assistant (PDA), etc.

[0268] Due to the thickness constraint of the mobile terminal, the optical system 100 according to the embodiment of the present disclosure can be sequentially arranged along the lateral direction of the mobile terminal. To this end, as described above, a right angle prism can also be arranged at the front end of the first lens 110.

[0269] The mobile terminal may be a smart phone, tablet computer, laptop computer, PDA, etc.

[0270] Although the above mainly describes the embodiments, these are only examples and are not intended to limit the present disclosure, and it can be seen that for those skilled in the art, various modifications and applications not illustrated herein are possible 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 defined by the appended claims.

[0271] [reference numerals]

[0272] 100: Optical system

[0273] 110: First lens

[0274] 120: Second lens

[0275] 130: The third lens

[0276] 140: The fourth lens

[0277] 150: Fifth lens

Claims

1. An optical system comprising an aperture, a first lens, a second lens, a third lens, a fourth lens and a fifth lens arranged in sequence from an object side to an image side, in, The first lens has positive refractive power, the second lens has negative refractive power, the third lens has positive refractive power, the fourth lens has positive refractive power, the fifth lens has negative refractive power, and The object-side surface and the image-side surface of the fifth lens both have circular asymmetric shapes.

2. The optical system according to claim 1, wherein: When the aperture is closed, the shortest distance between the aperture and the object-side surface of the first lens is less than 0.2 mm.

3. The optical system according to claim 1, wherein: The distance between the image-side surface of the first lens and the object-side surface of the second lens and the distance between the image-side surface of the second lens and the object-side surface of the third lens are both smaller than the distance between the image-side surface of the third lens and the object-side surface of the fourth lens, and The maximum effective diameters among the object-side surface and the image-side surface of the first lens, the object-side surface and the image-side surface of the second lens, and the object-side surface and the image-side surface of the third lens are smaller than the minimum effective diameters among the object-side surface and the image-side surface of the fourth lens and the object-side surface and the image-side surface of the fifth lens.

4. The optical system according to claim 3, wherein: The first lens, the second lens, the third lens, and the fourth lens are circularly symmetric lenses.

5. The optical system according to claim 3, wherein: At least one of the object-side surface and the image-side surface of the first lens, the object-side surface and the image-side surface of the second lens, and the object-side surface and the image-side surface of the third lens includes a critical point where the inclination angle is 0.

6. The optical system according to claim 5, wherein: at least two of the object-side surface of the fourth lens, the image-side surface of the fourth lens, and the object-side surface of the fifth lens do not include the critical point, The object-side surface of the fourth lens is concave toward the object side, The image-side surface of the fourth lens is convex toward the image side, and An object-side surface of the fifth lens is concave toward the object side.

7. The optical system according to claim 3, wherein: At the same distance from the optical axis, a sag value of the object-side surface of the fifth lens in a first direction and a sag value in a second direction perpendicular to the first direction are different from each other, and A sag value of an image-side surface of the fifth lens in the first direction and a sag value in the second direction at the same distance from the optical axis are different from each other.

8. The optical system according to claim 7, wherein: At the same distance from the optical axis, the sag value in the first direction or the sag value in the second direction of the object-side surface of the fifth lens is different from a sag value in a third direction between the first direction and the second direction.

9. The optical system according to claim 7, wherein: At the same distance from the optical axis, the deviation between the sagittal value of the image side surface of the fifth lens in the first direction and the sagittal value in the second direction is greater than the deviation between the sagittal value of the object side surface of the fifth lens in the first direction and the sagittal value in the second direction.

10. The optical system according to claim 1, wherein: The F number is below 2.45, the field of view, i.e., FOV, is above 80 degrees, and the relative illumination, i.e., RI, is above 40%.

Images