Optical system and camera module comprising the same

Abstract

A zoom optical system according to an embodiment of the present application includes, in order from the object side to the image side, a first lens group, a second lens group, a third lens group, and a fourth lens group, wherein the second lens group and the third lens group are movable, and defined by the following mathematical expression at a telephoto effective focal length (EFL): EFL < 1000 mm tele wherein EFL imageD represents a half diagonal length of an image sensor pixel area.

Description

Technical Field

[0001] The embodiments relate to an optical system and a camera module including the optical system. Background Technology

[0002] With the development of the performance of camera modules embedded in portable terminals, even camera modules in portable terminals need to have autofocus functionality.

[0003] In the process of converting external light into digital images or digital video to enable autofocus in a camera module of a portable terminal, magnification can be increased through digital processing. Therefore, zooming can be performed only at predetermined magnifications such as 1x, 3x, and 5x, and as the magnification increases, resolution decreases and digital degradation occurs.

[0004] Meanwhile, to enable autofocus in camera modules of portable devices, techniques have been explored involving moving the lens to adjust the distance between the lens and the image sensor. However, designing a movable optical system within a confined space in a portable device is not easy. Summary of the Invention

[0005] Technical issues

[0006] The technical objective of this invention is to provide a zoom optical system and a camera module including the system.

[0007] The objectives to be addressed by the embodiments are not limited to these, but also include objectives or effects known from the technical solutions or modes of the invention described below.

[0008] Technical solution

[0009] One aspect of the present invention provides a zoom optical system comprising a first lens group, a second lens group, a third lens group, and a fourth lens group arranged sequentially in a direction from the object side to the image side, wherein the second and third lens groups are movable, and the effective focal length (EFL) in telephoto mode is defined by the following expression.

[0010]

[0011] Here, EFL tele It is the EFL of the zoom optical system in telephoto mode, and H imageD It is half the diagonal length of the pixel region of the image sensor.

[0012] The first lens group may include three or more lenses, the second lens group may include two or more lenses, the third lens group may include two or more lenses, the fourth lens group may include one lens, and the number of lenses in each of the second and third lens groups may be less than the number of lenses in the first lens group.

[0013] The EFL in wide angle mode is defined by the following expression.

[0014]

[0015] Here, EFL wide It is the EFL of the zoom optical system in wide-angle mode, and H imageD It is half the diagonal length of the pixel region of the image sensor.

[0016] When zooming from wide-angle mode to telephoto mode, the travel distance of the second lens group is defined by the following expression.

[0017]

[0018] Here, TTL (Total Track Length) is the distance from the surface of the image sensor to the first surface of the zoom optical system, and STROKE2 is the travel distance of the second lens group.

[0019] When zooming from wide-angle mode to telephoto mode, the travel distance of the third lens group is defined by the following expression.

[0020]

[0021] Here, TTL is the distance from the surface of the image sensor to the first surface of the zoom optical system, and STROKE3 is the travel distance of the third lens group.

[0022] The first lens group may include multiple lenses; among the multiple lenses included in the first lens group, the lens disposed on the image side may have positive refractive power; and among the multiple lenses included in the first lens group, the lens disposed on the object side may have negative refractive power.

[0023] The second lens group may include at least two lenses; and the at least two lenses included in the second lens group may have an Abbe number as defined by the following expression.

[0024] |ABBE4-ABBE5|>10

[0025] Here, ABBE4 is the Abbe number of the lens disposed on the object side of the two lenses included in the second lens group, and ABBE5 is the Abbe number of the lens disposed on the image side of the two lenses included in the second lens group.

[0026] The second lens group may include at least one of a glass lens and a plastic lens.

[0027] The maximum diameter of the plurality of lenses included in the first and fourth lens groups and the maximum diameter of the plurality of lenses included in the second and third lens groups can be defined by the following expressions.

[0028]

[0029] Here, APER fix It is the maximum diameter of the lenses included in the first and fourth lens groups, which are fixed groups, and APER mov It is the maximum diameter of the lenses included in the second and third lens groups, which are moving groups.

[0030] The principal ray angle (CRA) can be greater than -5° and less than 5°.

[0031] The zoom optical system may also include a right-angle prism positioned in front of the first lens group.

[0032] Another aspect of the present invention provides a zoom optical system comprising a first lens group, a second lens group, a third lens group, and a fourth lens group arranged sequentially in a direction from the object side to the image side, wherein the second lens group and the third lens group are movable and are defined in wide-angle mode by the following expression.

[0033]

[0034] Here, EFL wide It is the EFL of the zoom optical system in wide-angle mode, and H imageD It is half the diagonal length of the pixel region of the image sensor.

[0035] Another aspect of the present invention provides a zoom optical system comprising a first lens group, a second lens group, a third lens group, and a fourth lens group arranged sequentially from the object side to the image side, wherein the first lens group and the fourth lens group are fixed, the second lens group and the third lens group are movable, the second lens group provides a zoom function, the third lens group provides a focusing function, the second lens group includes a first lens and a second lens, and the difference in Abbe number between the first lens and the second lens is 10 or greater.

[0036] Another aspect of the present invention provides a zoom optical system comprising a first lens group, a second lens group, a third lens group, and a fourth lens group arranged sequentially from the object side to the image side, wherein the first lens group and the fourth lens group are fixed, and the second lens group and the third lens group are movable. The second lens group provides a zoom function, and the third lens group provides a focusing function. The image-side surface of the first lens, which is closest to the image-side surface of the lens included in the first lens group, is concave, and the object-side surface of the second lens, which is closest to the object-side surface of the lens included in the second lens group, is convex. Furthermore, when the distance between the first lens group and the second lens group is at its minimum, the center of curvature of the object-side surface of the second lens is positioned closer to the image side than the two ends of the image-side surface of the first lens.

[0037] Beneficial effects

[0038] According to embodiments of the present invention, an optical system capable of zooming not only at low magnification but also at high magnification, and a camera module including the optical system, can be obtained. In the optical system according to embodiments of the present invention, zoom can be continuously adjusted, and high resolution can be maintained even at high magnification. Attached Figure Description

[0039] Figure 1 This is a diagram illustrating a zoom optical system according to a first embodiment of the present invention.

[0040] Figure 2a This is a cross-sectional view of the zoom optical system in wide-angle mode according to the first embodiment of the present invention.

[0041] Figure 2b This is a cross-sectional view of the zoom optical system in the intermediate mode according to the first embodiment of the present invention.

[0042] Figure 2c This is a cross-sectional view of the zoom optical system in telephoto mode according to the first embodiment of the present invention.

[0043] Figure 3a It is a diagram showing the longitudinal spherical aberration, astigmatism curves, and distortion of light at wavelengths of 435nm, 486nm, 546nm, 587nm, and 656nm in the optical system of the wide-angle mode according to the first embodiment.

[0044] Figure 3b This is a diagram showing the longitudinal spherical aberration, astigmatism curves, and distortion of light at wavelengths of 435nm, 486nm, 546nm, 587nm, and 656nm in an optical system in an intermediate mode according to the first embodiment.

[0045] Figure 3cIt is a diagram showing the longitudinal spherical aberration, astigmatism curves, and distortion of light at wavelengths of 435nm, 486nm, 546nm, 587nm, and 656nm in the optical system of the telephoto mode according to the first embodiment.

[0046] Figure 4a This is a graph illustrating the diffraction modulation transfer function (MTF) in the optical system in wide-angle mode according to the first embodiment.

[0047] Figure 4b This is a diagram showing the diffraction MTF in the optical system in the intermediate mode according to the first embodiment.

[0048] Figure 4c This is a diagram illustrating the diffraction MTF in the optical system of the telephoto mode according to the first embodiment.

[0049] Figure 5 This is a diagram showing the relative illumination of a zoom optical system according to a first embodiment of the present invention.

[0050] Figure 6 This is a diagram illustrating a zoom optical system according to a second embodiment of the present invention.

[0051] Figure 7a This is a cross-sectional view of the zoom optical system in wide-angle mode according to a second embodiment of the present invention.

[0052] Figure 7b This is a cross-sectional view of the zoom optical system in the intermediate mode according to the second embodiment of the present invention.

[0053] Figure 7c This is a cross-sectional view of the zoom optical system in telephoto mode according to the second embodiment of the present invention.

[0054] Figure 8a This is a diagram showing the longitudinal spherical aberration, astigmatism curves, and distortion of an optical system in wide-angle mode for light with wavelengths of 435nm, 486nm, 546nm, 587nm, and 656nm according to the second embodiment.

[0055] Figure 8b This is a diagram showing the longitudinal spherical aberration, astigmatism curves, and distortion in an optical system in intermediate mode for light wavelengths of 435nm, 486nm, 546nm, 587nm, and 656nm, according to the second embodiment.

[0056] Figure 8c This is a diagram showing the longitudinal spherical aberration, astigmatism curves, and distortion of an optical system in telephoto mode for light with wavelengths of 435nm, 486nm, 546nm, 587nm, and 656nm, according to the second embodiment.

[0057] Figure 9a This is a graph illustrating the diffraction modulation transfer function (MTF) in the optical system in wide-angle mode according to the second embodiment.

[0058] Figure 9b This is a diagram illustrating the diffraction MTF in an optical system in an intermediate mode according to an embodiment.

[0059] Figure 9c This is a diagram illustrating the diffraction MTF in the optical system of the telephoto mode according to the second embodiment.

[0060] Figure 10 This is a diagram illustrating the relative illumination of the zoom optical system according to a second embodiment of the present invention.

[0061] Figure 11 This is a view of a portion of a portable terminal that uses a camera module according to an embodiment of the present invention. Detailed Implementation

[0062] In the following, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0063] However, the spirit of the present invention is not limited to the embodiments described and can be implemented using various other embodiments, and at least one component of these embodiments can be selectively coupled, substituted and used within the scope of the spirit of the present invention.

[0064] Furthermore, unless the context explicitly and specifically defines otherwise, all terms used herein (including technical and scientific terms) are to be interpreted as having the meaning commonly used by those skilled in the art, and the meaning of commonly used terms will be interpreted in the context of the relevant art, such as those defined in commonly used dictionaries.

[0065] Furthermore, the terminology used in the embodiments of the present invention is considered descriptive and not a limitation thereof.

[0066] In this specification, unless the context clearly indicates otherwise, the singular form includes its plural form, and in the case of describing "at least one (or one or more) of A, B and C", this may include at least one combination of all possible combinations of A, B, and C.

[0067] Furthermore, in the description of the components of the present invention, terms such as "first", "second", "A", "B", "(a)" and "(b)" may be used.

[0068] The term is only used to distinguish one element from another, and the nature and order of the elements are not limited by the term.

[0069] In addition, it should be understood that when an element is described as being “connected or coupled” to another element, such a description may include not only the case where the element is directly connected or coupled to another element, but also the case where the element is connected or coupled to another element, and the other element is disposed between them.

[0070] Furthermore, when any element is described as being formed or arranged "above or below" another element, this description includes not only cases where the two elements are formed or arranged in direct contact with each other, but also cases where one or more other elements are inserted between the two elements. Additionally, when an element is described as being formed "above or below" another element, such a description may include not only cases where the element is formed on the upper side, but also cases where the element is formed on the lower side relative to the other element. Figure 1 This is a diagram illustrating a zoom optical system according to a first embodiment of the present invention.

[0071] refer to Figure 1 According to a first embodiment of the present invention, a zoom optical system may include a first lens group 100, a second lens group 200, a third lens group 300, and a fourth lens group 400 arranged sequentially in a direction from the object side to the image side. A right-angle prism may also be provided before the first lens group 100. In this case, the zoom optical system may include a right-angle prism, a first lens group 100, a second lens group 200, a third lens group 300, and a fourth lens group 400 arranged sequentially in a direction from the object side to the image side.

[0072] According to a first embodiment of the present invention, the first lens group 100 includes a plurality of lenses. The first lens group 100 may include at least three lenses. When the first lens group 100 includes one lens, it may be difficult to correct the resolution at maximum magnification, and when the first lens group 100 includes four or more lenses, the overall size of the zoom optical system may increase. Therefore, the first lens group 100 may preferably include three lenses 110, 120 and 130.

[0073] The first lens group 100 is fixed relative to the image side. The first lens group 100 is fixed relative to the surface of the sensor 10. That is, multiple lenses are fixed relative to the image side. When the first lens group 100 includes three lenses, the three lenses 110, 120 and 130 can be fixed relative to the image side.

[0074] The second lens group 200 includes multiple lenses. The second lens group 200 may include at least two lenses. When the second lens group 200 includes one lens, it may be difficult to correct the resolution at maximum magnification, and when the second lens group 200 includes three or more lenses, the overall size of the zoom optical system may increase. Therefore, the second lens group 200 may preferably include two lenses 210 and 220.

[0075] The second lens group 200 is movable. All the multiple lenses included in the second lens group 200 can move along the central axis of the lens. Both lenses 210 and 220 included in the second lens group 200 can also move along the central axis of the lens. When the second lens group 200 includes three or more lenses, the size and weight of the second lens group 200 increase, and the driving power can increase when the second lens group 200 moves. Therefore, the second lens group 200 can include two lenses 210 and 220. The focal length can be continuously adjusted according to the movement of the second lens group 200. As the second lens group 200 moves, the magnification can be continuously adjusted. Therefore, the second lens group 200 can be used as a zoom group.

[0076] The third lens group 300 includes multiple lenses. The third lens group 300 may include at least two lenses. When the third lens group 300 includes one lens, it may be difficult to correct the resolution at maximum magnification, and when the third lens group 300 includes three or more lenses, the overall size of the zoom optical system may increase. Therefore, the third lens group 300 may preferably include two lenses 310 and 320.

[0077] The third lens group 300 is movable. All the multiple lenses included in the third lens group 300 are movable along the central axis of the lens. Two lenses 310 and 320 included in the third lens group 300 can move together along the central axis of the lens. When the third lens group 300 includes three or more lenses, the size and weight of the third lens group 300 increase, and the driving power increases when the third lens group 300 moves. Therefore, the third lens group 300 can include two lenses 310 and 320. As the third lens group 300 moves, the focal length can be adjusted. The third lens group 300 can be used as a focusing group.

[0078] The fourth lens group 400 includes one or more lenses. When the fourth lens group 400 includes three or more lenses, the overall size of the zoom optical system increases, and therefore the fourth lens group 400 may preferably include a lens 410.

[0079] The fourth lens group 400 is fixed relative to the image side. The fourth lens group 400 is fixed relative to the surface of the sensor 10. That is, multiple lenses are fixed relative to the image side. When the fourth lens group 400 includes one lens, a lens 410 can be fixed relative to the image side.

[0080] According to a first embodiment of the present invention, the filter 20 and the image sensor 10 may be sequentially arranged after the fourth lens group 400. In this case, the filter 20 may be an infrared (IR) filter. Therefore, the filter 20 can block near-IR light, for example, light with wavelengths of 700 nm to 1100 nm, from incident on the camera module. Furthermore, the image sensor 10 may be connected to a printed circuit board via a wire.

[0081] The filter 20 may also include a foreign object blocking filter and an IR filter arranged sequentially in the direction from the object side to the image side. When the filter 20 includes a foreign object blocking filter, it can prevent foreign objects generated during the movement of the third lens group 300 from being introduced into the IR filter or the image sensor 10.

[0082] The magnification of the zoom optical system can be changed according to the movement of the second lens group 200 and the third lens group 300. For example, the magnification of the zoom optical system can be continuously increased or decreased within the range of 3x to 10x depending on the movement of the second lens group 200 and the third lens group 300. According to the first embodiment, the zoom optical system can have a magnification of 3x in wide-angle mode and a magnification of 10x in telephoto mode. Furthermore, the continuous increase or decrease in magnification does not refer to an intermittent increase or decrease in magnification in a digital manner, but rather to a linear increase or decrease within that range.

[0083] Each of the second lens group 200 and the third lens group 300 can move independently. For example, when the wide-angle mode is switched to the telephoto mode, the distance between the second lens group 200 and the third lens group 300 can increase in the direction from the starting point of movement (the starting point of the wide-angle mode) to the predetermined point and gradually decrease in the direction from the predetermined point to the ending point of movement (the ending point of the telephoto mode).

[0084] The effective focal length (EFL) of the zoom optical system according to a first embodiment of the present invention will be described.

[0085] The EFL of the zoom optical system in telephoto mode can be expressed as the following expression 1.

[0086] [Expression 1]

[0087]

[0088] Here, EFL teleIt is the EFL of the zoom optical system in telephoto mode, and H imageD This is half the diagonal length of the pixel area of ​​the image sensor. The unit can be [mm]. The pixel area of ​​the image sensor can be the region within the image sensor where light-receiving pixels are arranged. The pixel area of ​​the image sensor can also be the area of ​​the total area of ​​the image sensor excluding the circuitry that converts the received light into electrical signals and the housing, etc.

[0089] The EFL of the zoom optical system in wide-angle mode can be expressed as the following expression 2.

[0090] [Expression 2]

[0091]

[0092] Here, EFL wide It is the EFL of the zoom optical system in wide-angle mode, and H imageD It is half the diagonal length of the pixel region of the image sensor.

[0093] The travel distance of the zoom optical system according to a first embodiment of the present invention will be described. The travel distance may refer to the distance that the lens group can move via the drive unit.

[0094] The travel distance of the second lens group 200 can be expressed as the following expression 3.

[0095] [Expression 3]

[0096]

[0097] Here, TTL (Total Track Length) can be the distance from the surface of the image sensor to the first surface of the zoom optical system. For example, TTL can be the distance from the surface of the first lens group 100 closest to the object to the upper surface of the image sensor 10 on which light is incident. In this specification, TTL can be used interchangeably with total length. STROKE2 can be the travel distance of the second lens group 200. The unit can be [mm].

[0098] The travel distance of the third lens group 300 can be expressed as the following expression 4.

[0099] [Expression 4]

[0100]

[0101] Here, TTL can be the distance from the surface of the image sensor to the first surface of the zoom optical system. STROKE3 can be the travel distance of the third lens group 300. The unit can be [mm].

[0102] When the travel distance is large, the size of the drive unit used to move the second lens group 200 and the third lens group 300 increases, thus making it difficult to install in a portable terminal. However, since the travel distance is achieved within approximately 1 / 5 to 1 / 3 of the TTL, the size of the drive unit can be very small, and the camera module can be miniaturized.

[0103] The Abbe number of a zoom optical system according to a first embodiment of the present invention will be described. The Abbe number can be a value obtained by quantizing the light dispersion properties of the lens.

[0104] The Abbe numbers of the multiple lenses included in the second lens group 200 can be different. When the second lens group 200 includes two lenses, the Abbe numbers of the two lenses included in the second lens group 200 can be expressed as the following expression 5.

[0105] [Expression 5]

[0106] |ABBE4-ABBE5|>10

[0107] Here, ABBE4 can be the Abbe number of the lens disposed on the object side of the two lenses included in the second lens group 200, and ABBE5 can be the Abbe number of the lens disposed on the image side of the two lenses included in the second lens group 200. According to the first embodiment, ABBE4 can be the Abbe number of the fourth lens 210, and ABBE5 can be the Abbe number of the fifth lens 220.

[0108] In the zoom optical system according to the first embodiment of the present invention, chromatic aberration can be reduced by arranging two lenses with a predetermined or greater Abbe number difference in the second lens group 200.

[0109] The aperture of the lens in the zoom optical system according to the first embodiment of the present invention will be described.

[0110] According to a first embodiment of the present invention, the aperture of each of the second lens group 200 and the third lens group 300 may be smaller than the aperture of each of the first lens group 100 and the fourth lens group 400. This can be as shown in the following expression 6.

[0111] [Expression 6]

[0112]

[0113] Here, APER fix It can be the maximum diameter of the lenses included in the first lens group 100 and the fourth lens group 400, which are fixed groups, and APER movThis can be the maximum diameter of the lenses included in the second lens group 200 and the third lens group 300, which are moving groups. For example, when the diameter of the first lens 110 is the largest among the diameters of the lenses included in the first lens group 100 and the fourth lens group 400, which are fixed groups, APER fix It can be the diameter of the first lens 110. When the diameter of the fourth lens 210 is the largest among the diameters of the lenses included in the second lens group 200 and the third lens group 300, which are moving groups, APER... mov It can be the diameter of the fourth lens 210.

[0114] By making the apertures of the second lens group 200 and the third lens group 300 smaller than those of the first lens group 100 and the fourth lens group 400, the weight of the second lens group 200 and the third lens group 300 can be reduced. Therefore, when the second lens group 200 and the third lens group 300, which are moving groups, move, power consumption can be reduced.

[0115] According to a first embodiment of the present invention, the plurality of lenses included in the first lens group 100 to the fourth lens group 400 may be lenses using D-cut technology. Each of the plurality of lenses included in the first lens group 100 to the fourth lens group 400 may be a D-cut lens in which a portion of its upper part and a portion of its lower part are cut. In this case, the ribs in the effective diameter of the plurality of lenses, as well as the upper and lower portions, may be cut, or only the ribs may be cut without cutting the effective diameter. According to one embodiment, the second lens group 200 and the third lens group may include lenses whose value is 1 obtained by dividing the length of the major axis of the effective diameter by the length of the minor axis of the effective diameter. That is, the length of the major axis of the effective diameter and the length of the minor axis of the effective diameter may be the same. For example, in the case of the fourth lens 210, the fifth lens 220, the sixth lens 310, and the seventh lens 320, only the upper and lower ribs may be cut, and the effective diameter may not be cut. In circular lenses, the problem is that the lens volume increases due to its vertical height. However, since the D-cutting technique is applied to the upper and lower parts of the multiple lenses according to the first embodiment of the present invention, the vertical height can be reduced, thereby reducing the lens volume.

[0116] According to a first embodiment of the present invention, a first lens group 100 may include a plurality of lenses with different refractive powers. Among the plurality of lenses included in the first lens group 100, the lens disposed on the image side may have positive (+) refractive power. Among the plurality of lenses included in the first lens group 100, the lens disposed on the object side may have negative (-) refractive power. According to an embodiment, the first lens group 100 may include a first lens 110 to a third lens 130 arranged sequentially in the direction from the object side to the image side. The first lens 110 may have positive refractive power, and the third lens 130 may have negative refractive power.

[0117] According to a first embodiment of the present invention, the first lens group 100 to the fourth lens group 400 may include plastic lenses. For example, all the plurality of lenses included in the second lens group 200 may be formed of plastic or glass material. The second lens group 200 may include glass lenses. For example, among the plurality of lenses included in the second lens group 200, the lens disposed on the object side may be formed of glass material, and the lens disposed on the image side may be formed of plastic material. In this case, the glass lens may be a glass mold lens manufactured by a glass molding process.

[0118] According to an embodiment of the present invention, in a zoom optical system, the principal ray angle (CRA) can be greater than -5° and less than 5°. The angle of incidence of light on the image sensor 10, i.e., the upper surface, can be greater than -5° and less than 5°. That is, the CRA of the zoom optical system according to an embodiment of the present invention can have any value between -5° and 5°. Since the angle of incidence of light on the image sensor 10 is small, the degree of freedom in selecting the sensor can be increased, and a zoom optical system with a compact size can be obtained.

[0119] Figure 2a This is a cross-sectional view of the zoom optical system in wide-angle mode according to the first embodiment of the present invention. Figure 2b This is a cross-sectional view of the zoom optical system in the middle mode according to the first embodiment of the present invention, and Figure 2c This is a cross-sectional view of the zoom optical system in telephoto mode according to the first embodiment of the present invention.

[0120] Tables 1 and 2 below show the optical properties of the lenses included in the zoom optical system according to the first embodiment of the present invention, and Tables 3 and 4 show the Koenig constants and aspherical coefficients of the lenses included in the zoom optical system according to the first embodiment of the present invention.

[0121] [Table 1]

[0122]

[0123]

[0124] [Table 2]

[0125]

[0126] [Table 3]

[0127]

[0128]

[0129] [Table 4]

[0130] 112 1.97373E-06 -1.87987E-07 1.07141E-08 -3.33813E-10 4.35935E-12 114 -2.38588E-06 1.48613E-07 -4.48414E-09 2.50584E-11 1.09043E-12 122 -1.84203E-05 1.38986E-06 -4.17441E-08 -6.40716E-10 4.88079E-11 124 -3.26791E-05 2.26542E-06 5.02798E-08 -1.44389E-08 5.07888E-10 132 3.32935E-05 -3.22887E-06 1.85617E-07 -5.41743E-09 4.02872E-11 134 6.98590E-05 -9.27051E-06 7.60204E-07 -3.54643E-08 7.25287E-10 212 -1.44325E-05 2.21865E-06 -2.14887E-07 1.20509E-08 -3.28005E-10 214 -9.03607E-05 1.53643E-05 -1.62809E-06 9.76259E-08 -2.53681E-09 222 -7.75660E-05 1.37428E-05 -1.52776E-06 9.68222E-08 -2.65877E-09 224 4.73928E-05 -1.37136E-05 2.31060E-06 -2.11616E-07 8.13307E-09 312 -2.27441E-04 7.18272E-05 -1.31877E-05 1.30000E-06 -5.31188E-08 314 -2.93213E-04 6.72856E-05 -9.43928E-06 7.27643E-07 -2.34145E-08 322 -4.47371E-04 1.09514E-04 -1.63616E-05 1.34098E-06 -4.58393E-08 324 -8.62195E-05 1.81752E-05 -2.39153E-06 1.75697E-07 -5.48114E-09 412 -2.03616E-05 2.43182E-06 -1.67566E-07 5.91606E-09 -7.67024E-11 414 1.78748E-06 -7.62197E-07 1.01520E-07 -6.26695E-09 1.50727E-10

[0131] refer to Figures 2a to 2c As per Tables 1 to 4, the zoom optical system includes a first lens group 100, a second lens group 200, a third lens group 300, and a fourth lens group 400 arranged sequentially from the object side to the image side. The first lens group 100 includes a first lens 110, a second lens 120, and a third lens 130 arranged sequentially from the object side to the image side. The second lens group 200 includes a fourth lens 210 and a fifth lens 220 arranged sequentially from the object side to the image side. The third lens group 300 includes a sixth lens 310 and a seventh lens 320 arranged sequentially from the object side to the image side. The fourth lens group 400 includes an eighth lens 410. In Table 1, thickness (mm) represents the distance from one lens surface to the next.

[0132] For example, the thickness corresponding to the object-side surface 112 of the first lens 110 represents the distance from the object-side surface 112 to the image-side surface 114 of the first lens 110. Specifically, the thickness corresponding to the object-side surface 112 of the first lens 110 represents 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.

[0133] The thickness corresponding to 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 thickness corresponding to 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.

[0134] The thickness corresponding to the image-side surface 134 of the third lens 130 represents the distance from the image-side surface 134 of the third lens 130 to the object-side surface 212 of the fourth lens 210. Specifically, the thickness corresponding to the image-side surface 134 of the third lens 130 represents the distance from the center of curvature of the image-side surface 134 of the third lens 130 to the center of curvature of the object-side surface 212 of the fourth lens 210.

[0135] In this case, since the second lens group 200 moves during the zoom from wide-angle mode to telephoto mode, the thickness of the image-side surface 134 corresponding to the third lens 130 can vary. The thickness of the image-side surface 134 corresponding to the third lens 130 can have a value between the shortest and longest distances. Referring to Table 1, the thickness of the image-side surface 134 corresponding to the third lens 130 can have the longest distance (8.4) in wide-angle mode. The thickness of the image-side surface 134 corresponding to the third lens 130 can have a value between the shortest and longest distances (3.335226) in intermediate mode. The thickness of the image-side surface 134 corresponding to the third lens 130 can have the shortest distance (0.4) in telephoto mode. The thickness of the image-side surface 134 corresponding to the third lens 130 is the same as the thickness of the image-side surface 224 corresponding to the fifth lens 220 and the thickness of the image-side surface 324 corresponding to the seventh lens 320.

[0136] Referring to Table 1, it can be seen that the difference between the Abbe numbers of the fourth lens 210 and the fifth lens 220 included in the second lens group 200 is 10 or greater. Specifically, since the Abbe number of the fourth lens 210 is 71.68 and the Abbe number of the fifth lens 220 is 19.24, the difference between the Abbe numbers of the two lenses is approximately 52, and thus it can be seen that the difference is 10 or greater.

[0137] Referring to Table 1, it can be seen that either the fourth lens 210 or the fifth lens 220 included in the second lens group 200 is a glass lens. Specifically, it can be seen that the fourth lens 210 is a glass-molded lens, and the fifth lens 220 is a plastic lens.

[0138] Referring to Table 2, each surface of the first lens 110 to the eighth lens 420 can be formed as convex or concave.

[0139] The first lens 110 may be a lens whose object-side surface 112 is convex to the object side. The first lens 110 may also be a lens whose image-side surface 114 is concave to the object side. The second lens 120 may be a lens whose object-side surface 122 is convex to the object side. The second lens 120 may also be a lens whose image-side surface 124 is convex to the object side. The third lens 130 may be a lens whose object-side surface 132 is concave to the object side. The third lens 130 may also be a lens whose image-side surface 134 is convex to the object side.

[0140] The fourth lens 210 can be a lens whose object-side surface 212 is convex to the object side. The fourth lens 210 can also be a lens whose image-side surface 214 is concave to the object side. The fifth lens 220 can be a lens whose object-side surface 222 is concave to the object side. The fifth lens 220 can also be a lens whose image-side surface 224 is convex to the object side. Meanwhile, when the distance between the first lens group 100 and the second lens group 200 is at its minimum (i.e., in telephoto mode), the center of curvature of the object-side surface 212 of the fourth lens 210 can be closer to the image side than the two ends of the image-side surface 134 of the third lens 130.

[0141] The sixth lens 310 may be a lens whose object-side surface 312 is concave to the object side. The sixth lens 310 may be a lens whose image-side surface 314 is concave to the object side. The seventh lens 320 may be a lens whose object-side surface 322 is concave to the object side. The seventh lens 320 may be a lens whose image-side surface 324 is convex to the object side.

[0142] The eighth lens 410 may be a lens whose object-side surface 412 is convex to the object side. The eighth lens 410 may also be a lens whose image-side surface 414 is concave to the object side.

[0143] refer to Figure 2a When the distance between the first lens group 100 and the second lens group 200 is d1a, the distance between the second lens group 200 and the third lens group 300 is d2a, and the distance between the third lens group 300 and the fourth lens group 400 is d3a, the zoom optical system can enter wide-angle mode (e.g., 3x magnification). That is, when the distance between the center of curvature of the image-side surface 134 of the third lens 130 and the center of curvature of the object-side surface 212 of the fourth lens 210 is d1a, the distance between the center of curvature of the image-side surface 224 of the fifth lens 220 and the center of curvature of the object-side surface 312 of the sixth lens 310 is d2a, and the distance between the center of curvature of the image-side surface 324 of the seventh lens 320 and the center of curvature of the object-side surface 412 of the eighth lens 410 is d3a, the zoom optical system can enter wide-angle mode.

[0144] exist Figure 2bIn this system, the zoom optical system can enter an intermediate mode when the distance between the first lens group 100 and the second lens group 200 is d1b, the distance between the second lens group 200 and the third lens group 300 is d2b, and the distance between the third lens group 300 and the fourth lens group 400 is d3b. Specifically, the zoom optical system can enter an intermediate mode when the distance between the center of curvature of the image-side surface 134 of the third lens 130 and the center of curvature of the object-side surface 212 of the fourth lens 210 is d1b, the distance between the center of curvature of the image-side surface 224 of the fifth lens 220 and the center of curvature of the object-side surface 312 of the sixth lens 310 is d2b, and the distance between the center of curvature of the image-side surface 324 of the seventh lens 320 and the center of curvature of the object-side surface 412 of the eighth lens 410 is d3b.

[0145] exist Figure 2c In this zoom optical system, when the distance between the first lens group 100 and the second lens group 200 is d1c, the distance between the second lens group 200 and the third lens group 300 is d2c, and the distance between the third lens group 300 and the fourth lens group 400 is d3c, the zoom optical system can enter telephoto mode (e.g., 10x magnification). That is, when the distance between the center of curvature of the image-side surface 134 of the third lens 130 and the center of curvature of the object-side surface 212 of the fourth lens 210 is d1c, the distance between the center of curvature of the image-side surface 224 of the fifth lens 220 and the center of curvature of the object-side surface 312 of the sixth lens 310 is d2c, and the distance between the center of curvature of the image-side surface 324 of the seventh lens 320 and the center of curvature of the object-side surface 412 of the eighth lens 410 is d3c, the zoom optical system can enter telephoto mode.

[0146] The distance between adjacent lens groups can change when changing the magnification from wide-angle mode to telephoto mode.

[0147] The distance between the first lens group 100 and the second lens group 200 can continuously change from d1a to d1b and from d1b to d1c. Referring to Table 1, in wide-angle mode, the distance d1a between the first lens group 100 and the second lens group 200 is 8.4 mm. In intermediate mode, the distance d1b between the first lens group 100 and the second lens group 200 is 3.335226 mm. In telephoto mode, the distance d1c between the first lens group 100 and the second lens group 200 is 0.4 mm. As described above, during the continuous change of magnification from wide-angle mode to intermediate mode and from intermediate mode to telephoto mode, the distance between the first lens group 100 and the second lens group 200 can continuously change from 8.4 mm to 3.335226 mm and from 3.335226 mm to 0.4 mm. In other words, as the magnification is continuously changed from wide-angle mode to telephoto mode, the distance between the first lens group 100 and the second lens group 200 can gradually decrease (d1a>d1b>d1c). That is, as the magnification is continuously changed from wide-angle mode to telephoto mode, the increase in the distance between the first lens group 100 and the second lens group 200 can gradually decrease.

[0148] The distance between the second lens group 200 and the third lens group 300 can continuously change from d2a to d2b and from d2b to d2c. Referring to Table 1, in wide-angle mode, the distance d2a between the second lens group 200 and the third lens group 300 is 4.033705 mm. In intermediate mode, the distance d2b between the second lens group 200 and the third lens group 300 is 4.098458 mm. In telephoto mode, the distance d1c between the second lens group 200 and the third lens group 300 is 5.977975 mm. As described above, during the continuous change of magnification from wide-angle mode to intermediate mode and from intermediate mode to telephoto mode, the distance between the second lens group 200 and the third lens group 300 can continuously change from 4.033705 mm to 4.098458 mm and from 4.098458 mm to 5.977975 mm. In other words, during the continuous change of magnification from wide-angle mode to telephoto mode, the distance between the second lens group 200 and the third lens group 300 may increase (d2a>d2b>d2c). In this case, the increase in the distance between the second lens group 200 and the third lens group 300 during the continuous change of magnification from wide-angle mode to telephoto mode can be significant.

[0149] The distance between the third lens group 300 and the fourth lens group 400 may vary continuously from d3a to d3b and from d3b to d3c. With reference to Table 1, in the wide-angle mode, the distance (d3a) between the third lens group 300 and the fourth lens group 400 is 1.447689 [mm]. In the intermediate mode, the distance (d3b) between the third lens group 300 and the fourth lens group 400 is 6.44771 [mm]. In the telephoto mode, the distance (d3c) between the third lens group 300 and the fourth lens group 400 is 7.50342 [mm]. As described above, during the process of continuously changing the magnification from the wide-angle mode to the intermediate mode and from the intermediate mode to the telephoto mode, the distance between the third lens group 300 and the fourth lens group 400 may vary continuously from 1.447689 [mm] to 6.44771 [mm] and from 6.44771 [mm] to 7.50342 [mm]. That is, during the process of continuously changing the magnification from the wide-angle mode to the telephoto mode, the distance between the third lens group 300 and the fourth lens group 400 may gradually increase (d3a<d3b<d3c). However, during the process of continuously changing the magnification from the wide-angle mode to the telephoto mode, the increase in the distance between the third lens group 300 and the fourth lens group 400 may gradually decrease.

[0150] As described above, the moving speed of the second lens group 200 and the moving speed of the third lens group 300 may be different from each other.

[0151] By moving the second lens group 200 and the third lens group 300, the magnification of the zoom optical system may be continuously changed from a magnification of 5x to a magnification of 10x.

[0152] Then, reference will be made to Figures 3a to 3c the simulation results of the longitudinal spherical aberration, astigmatic field curves, and distortion of the zoom optical system according to the first embodiment of the present invention. The longitudinal spherical aberration refers to the longitudinal spherical aberration according to each wavelength, the astigmatic field curves refer to the aberration properties of the tangential plane and the sagittal plane according to the height of the image surface, and the distortion refers to the distortion degree according to the height of the image surface.

[0153] Figure 3a is a diagram showing the longitudinal spherical aberration, astigmatic field curves, and distortion of light with wavelengths of 435 nm, 486 nm, 546 nm, 587 nm, and 656 nm in the optical system in the wide-angle mode according to the first embodiment.

[0154] Figure 3b is a diagram showing the longitudinal spherical aberration, astigmatic field curves, and distortion of light with wavelengths of 435 nm, 486 nm, 546 nm, 587 nm, and 656 nm in the optical system in the telephoto mode according to the first embodiment.

[0155] Figure 3c It is a graph showing the longitudinal spherical aberration, astigmatism curves, and distortion of light at wavelengths of 435 nm, 486 nm, 546 nm, 587 nm, and 656 nm in the optical system of the telephoto mode according to the first embodiment.

[0156] refer to Figures 3a to 3c It can be seen that the longitudinal spherical aberration from the center to the edge of the image sensor is in the range of -0.02 mm to 0.05 mm, independent of wavelength. Specifically, in wide-angle mode, the longitudinal spherical aberration is in the range of approximately -0.01 mm to 0.05 mm, and in intermediate mode, the longitudinal spherical aberration is in the range of -0.01 mm to 0.05 mm. In telephoto mode, even when some wavelengths are outside the range, the longitudinal spherical aberration is still in the range of approximately -0.02 mm to 0.05 mm, except for those wavelengths.

[0157] refer to Figures 3a to 3c It can be seen that the astigmatism curve from the center to the edge of the image sensor is in the range of -0.025 mm to 0.025 mm, independent of wavelength. Specifically, it can be seen that in wide-angle mode, the astigmatism curve is in the range of approximately -0.01 mm to 0 mm, and in intermediate mode, the astigmatism curve is in the range of -0.025 mm to 0.01 mm. It can be seen that in telephoto mode, the astigmatism curve is in the range of approximately -0.025 mm to 0.025 mm.

[0158] refer to Figures 3a to 3c It can be seen that regardless of the wavelength, the distortion from the center to the edge of the image sensor ranges from -2% to 0%. Specifically, it can be seen that in wide-angle mode, the distortion is approximately in the range of -2% to 0%, and in intermediate mode, the distortion is in the range of -1% to 0%. It can be seen that in telephoto mode, the distortion is in the range of -1% to 0%.

[0159] Then, refer to Figures 4a to 4c The simulation results of the modulation transfer function (MTF) of the zoom optical system according to the first embodiment of the present invention are described. MTF is one of the performance measurement methods for optical systems.

[0160] Figure 4a This is a diagram illustrating the diffraction MTF in the optical system in wide-angle mode according to the first embodiment. Figure 4b This is a diagram showing the diffraction MTF in the optical system in the intermediate mode according to the first embodiment. Figure 4c This is a diagram illustrating the diffraction MTF in the optical system of the telephoto mode according to the first embodiment.

[0161] refer to Figures 4a to 4c It can be seen that the zoom optical system according to the embodiment of the present invention has a value close to the diffraction limit as a limit value near the 0 [mm] defocus position in each of the wide-angle mode, intermediate mode and telephoto mode.

[0162] Figure 5 This is a diagram showing the relative illumination of a zoom optical system according to a first embodiment of the present invention.

[0163] refer to Figure 5 It can be seen that, in the zoom optical system according to the first embodiment of the present invention, the relative illumination value is 45% or greater in all areas of the wide-angle mode (zoom position 1), intermediate mode (zoom position 2), and telephoto mode (zoom position 3). It can also be seen that the relative illumination value is 90% or greater in all areas of the intermediate and telephoto modes, and even in the case of the wide-angle mode, the relative illumination value is 90% or greater in the range of 0 to 1.5 [mm].

[0164] As described above with reference to the embodiments, it can be seen that the optical system according to the embodiments of the present invention has high aberration properties.

[0165] refer to Figure 6 According to a second embodiment of the present invention, a zoom optical system may include a first lens group 100, a second lens group 200, a third lens group 300, and a fourth lens group 400 arranged sequentially from the object side to the image side. A right-angle prism may also be provided before the first lens group 100. In this case, the zoom optical system may include a right-angle prism, a first lens group 100, a second lens group 200, a third lens group 300, and a fourth lens group 400 arranged sequentially from the object side to the image side.

[0166] According to a second embodiment of the present invention, the first lens group 100 includes a plurality of lenses. The first lens group 100 may include at least three lenses. When the first lens group 100 includes one lens, it may be difficult to correct the resolution at maximum magnification, and when the first lens group 100 includes four or more lenses, the overall size of the zoom optical system may increase. Therefore, the first lens group 100 may preferably include three lenses 110, 120 and 130.

[0167] The first lens group 100 is fixed relative to the image side. The first lens group 100 is fixed relative to the surface of the sensor 10. That is, multiple lenses are fixed relative to the image side. When the first lens group 100 includes three lenses, the three lenses 110, 120 and 130 can be fixed relative to the image side.

[0168] The second lens group 200 includes multiple lenses. The second lens group 200 may include at least two lenses. When the second lens group 200 includes one lens, it may be difficult to correct the resolution at maximum magnification, and when the second lens group 200 includes three or more lenses, the overall size of the zoom optical system may increase. Therefore, the second lens group 200 may preferably include two lenses 210 and 220.

[0169] The second lens group 200 is movable. All the multiple lenses included in the second lens group 200 can move along the central axis of the lens. Both lenses 210 and 220 included in the second lens group 200 can also move along the central axis of the lens. When the second lens group 200 includes three or more lenses, the size and weight of the second lens group 200 increase, and the driving power may increase when the second lens group 200 moves. Therefore, the second lens group 200 can include two lenses 210 and 220. The focal length can be continuously adjusted according to the movement of the second lens group 200. As the second lens group 200 moves, the magnification can be continuously adjusted. Therefore, the second lens group 200 can be used as a zoom group.

[0170] The third lens group 300 includes multiple lenses. The third lens group 300 may include at least two lenses. When the third lens group 300 includes one lens, it may be difficult to correct the resolution at maximum magnification, and when the third lens group 300 includes three or more lenses, the overall size of the zoom optical system may increase. Therefore, the third lens group 300 may preferably include two lenses 310 and 320.

[0171] The third lens group 300 is movable. All the lenses included in the third lens group 300 are movable along the central axis of the lens. Both lenses 310 and 320 in the third lens group 300 are movable along the central axis of the lens. When the third lens group 300 includes three or more lenses, the size and weight of the third lens group 300 increase, and the driving power may increase when the third lens group 300 moves. Therefore, the third lens group 300 may include two lenses 310 and 320. As the third lens group 300 moves, the focal length can be adjusted. The third lens group 300 can be used as a focusing group.

[0172] The fourth lens group 400 includes one or more lenses. The fourth lens group 400 may include two lenses. When the fourth lens group 400 includes three or more lenses, the overall size of the zoom optical system increases, and therefore the fourth lens group 400 may preferably include two lenses 410 and 420.

[0173] The fourth lens group 400 is fixed relative to the image side. The fourth lens group 400 is fixed relative to the surface of the sensor 10. That is, multiple lenses are fixed relative to the image side. When the fourth lens group 400 includes two lenses, the two lenses 410 and 420 can be fixed relative to the image side.

[0174] According to a second embodiment of the present invention, the filter 20 and the image sensor 10 can be sequentially arranged after the fourth lens group 400. In this case, the filter 20 can be an IR filter. Therefore, the filter 20 can block near-infrared light, such as light with wavelengths of 700 nm to 1100 nm, from incident on the camera module. Furthermore, the image sensor 10 can be connected to a printed circuit board via a wire.

[0175] The filter 20 may also include a foreign object blocking filter and an IR filter arranged sequentially from the object side to the image side. When the filter 20 includes a foreign object blocking filter, it can prevent foreign objects generated during the movement of the third lens group 300 from being introduced into the IR filter or the image sensor 10.

[0176] The magnification of the zoom optical system can be changed according to the movement of the second lens group 200 and the third lens group 300. For example, the magnification of the zoom optical system can be continuously increased or decreased within the range of 3x to 10x depending on the movement of the second lens group 200 and the third lens group 300. According to the second embodiment, the zoom optical system can have a magnification of 3x in wide-angle mode and a magnification of 10x in telephoto mode. Furthermore, the continuous increase or decrease in magnification does not refer to an intermittent increase or decrease in magnification in a digital manner, but rather to a linear increase or decrease within that range.

[0177] Each of the second lens group 200 and the third lens group 300 can move independently. For example, when switching from wide-angle mode to telephoto mode, the distance between the second lens group 200 and the third lens group 300 can increase in the direction from the starting point of movement (starting point of wide-angle mode) to a predetermined point and gradually decrease in the direction from the predetermined point to the ending point of movement (ending point of telephoto mode).

[0178] The EFL of a zoom optical system according to a second embodiment of the present invention will be described.

[0179] The EFL of the zoom optical system in telephoto mode can be expressed as the following expression 7.

[0180] [Expression 7]

[0181]

[0182] Here, EFL teleThe EFL of the zoom optical system in telephoto mode, not and H imageD This is half the diagonal length of the pixel area of ​​the image sensor. The unit can be [mm]. The pixel area of ​​the image sensor can be the region within the image sensor where light-receiving pixels are arranged. The pixel area of ​​the image sensor can be the area within the total area of ​​the image sensor excluding the circuitry that converts the received light into electrical signals and the housing, etc.

[0183] The EFL of the zoom optics system in wide-angle mode can be expressed as the following expression 8.

[0184] [Expression 8]

[0185]

[0186] Here, EFL wide It is the EFL of the zoom optical system in wide-angle mode, and H imageD It is half the diagonal length of the pixel region of the image sensor.

[0187] The travel distance of a zoom optical system according to a second embodiment of the present invention will be described. The travel distance can refer to the distance that the lens group can move via the drive unit.

[0188] The travel distance of the second lens group 200 can be expressed as the following expression 9.

[0189] [Expression 9]

[0190]

[0191] Here, TTL (Total Track Length) can be the distance from the surface of the image sensor to the first surface of the zoom optical system. For example, TTL can be the distance from the surface of the first lens group 100 closest to the object to the upper surface of the image sensor 10 where light is incident. In this specification, TTL can be used interchangeably with total length. STROKE2 can be the travel distance of the second lens group 200. The unit can be [mm].

[0192] The travel distance of the third lens group 300 can be expressed as the following expression 10.

[0193] [Expression 10]

[0194]

[0195] Here, TTL can be the distance from the surface of the image sensor to the first surface of the zoom optical system. STROKE3 can be the travel distance of the third lens group 300. The unit can be [mm].

[0196] When the travel distance is large, the size of the drive unit used to move the second lens group 200 and the third lens group 300 increases, thus making it difficult to install in a portable terminal. However, since the travel distance is achieved within approximately 1 / 5 to 1 / 3 of the TTL, the size of the drive unit can be very small, and therefore the camera module can be miniaturized.

[0197] The Abbe number of a zoom optical system according to a second embodiment of the present invention will be described. The Abbe number can be a value obtained by quantizing the light dispersion properties of the lens.

[0198] The Abbe numbers of the multiple lenses included in the second lens group 200 can be different. When the second lens group 200 includes two lenses, the Abbe numbers of the two lenses included in the second lens group 200 can be expressed as the following expression 11.

[0199] [Expression 11]

[0200] |ABBE4-ABBE5|>10

[0201] Here, ABBE4 can be the Abbe number of the lens disposed on the object side of the two lenses included in the second lens group 200, and ABBE5 can be the Abbe number of the lens disposed on the image side of the two lenses included in the second lens group 200. According to the second embodiment, ABBE4 can be the Abbe number of the fourth lens 210, and ABBE5 can be the Abbe number of the fifth lens 220.

[0202] In the zoom optical system according to the second embodiment of the present invention, chromatic aberration can be reduced by arranging two lenses with a predetermined or greater Abbe number difference in the second lens group 200.

[0203] The aperture of the lens in the zoom optical system according to a second embodiment of the present invention will be described.

[0204] According to a second embodiment of the present invention, the aperture of each of the second lens group 200 and the third lens group 300 may be smaller than the aperture of each of the first lens group 100 and the fourth lens group 400. This can be expressed as the following expression 12.

[0205] [Expression 12]

[0206]

[0207] Here, APER fix It can be the maximum diameter of the lenses included in the first lens group 100 and the fourth lens group 400, which are fixed groups, and APER movThis can be the maximum diameter of the lenses included in the second lens group 200 and the third lens group 300, which are moving groups. For example, when the diameter of the first lens 110 is the largest among the diameters of the lenses included in the first lens group 100 and the fourth lens group 400, which are fixed groups, APER... fix It can be the diameter of the first lens 110. When the diameter of the fourth lens 210 is the largest among the diameters of the lenses included in the second lens group 200 and the third lens group 300, which are moving groups, APER... mov It can be the diameter of the fourth lens 210.

[0208] By making the apertures of the second lens group 200 and the third lens group 300 smaller than those of the first lens group 100 and the fourth lens group 400, the weight of the second lens group 200 and the third lens group 300 can be reduced. Therefore, when the second lens group 200 and the third lens group 300, which are moving groups, move, power consumption can be reduced.

[0209] According to a second embodiment of the present invention, the plurality of lenses included in the first lens group 100 to the fourth lens group 400 may be lenses using D-cutting technology. Each of the plurality of lenses included in the first lens group 100 to the fourth lens group 400 may be a D-cut lens in which a portion of its upper part and a portion of its lower part are cut. In this case, the ribs of the plurality of lenses and the upper and lower portions of the effective diameter may be cut, or only the ribs may be cut without cutting the effective diameter. According to one embodiment, the second lens group 200 and the third lens group may include lenses whose value is 1 obtained by dividing the length of the major axis of the effective diameter by the length of the minor axis of the effective diameter. That is, the length of the major axis of the effective diameter and the length of the minor axis of the effective diameter may be the same. For example, in the case of the fourth lens 210, the fifth lens 220, the sixth lens 310 and the seventh lens 320, only the upper and lower ribs may be cut, and the effective diameter may not be cut. In circular lenses, the problem is that the lens volume increases due to its vertical height. However, since the D-cutting technique is applied to the upper and lower parts of the multiple lenses according to the second embodiment of the present invention, the vertical height can be reduced, thereby reducing the lens volume.

[0210] According to a second embodiment of the present invention, the first lens group 100 may include a plurality of lenses with different refractive powers. Among the plurality of lenses included in the first lens group 100, the lens disposed on the image side may have positive (+) refractive power. Among the plurality of lenses included in the first lens group 100, the lens disposed on the object side may have negative (-) refractive power. According to an embodiment, the first lens group 100 may include a first lens 110 to a third lens 130 arranged sequentially from the object side to the image side. The first lens 110 may have positive refractive power, and the third lens 130 may have negative refractive power.

[0211] According to a second embodiment of the present invention, the first lens group 100 to the fourth lens group 400 may include plastic lenses. For example, all the plurality of lenses included in the second lens group 200 may be formed of plastic or glass material. The second lens group 200 may include glass lenses. For example, among the plurality of lenses included in the second lens group 200, the lens disposed on the object side may be formed of glass material, and the lens disposed on the image side may be formed of plastic material. In this case, the glass lens may be a glass-molded lens manufactured by a glass molding method.

[0212] According to an embodiment of the present invention, in a zoom optical system, the principal ray angle (CRA) can be greater than -5° and less than 5°. The angle of incidence of light on the image sensor 10 (i.e., the upper surface) can be greater than -5° and less than 5°. That is, the CRA of the zoom optical system according to an embodiment of the present invention can have any value between -5° and 5°. Since the angle of incidence of light on the image sensor 10 is small, the degree of freedom in selecting the sensor can be increased, and a zoom optical system with a compact size can be obtained.

[0213] Figure 7a This is a cross-sectional view of the zoom optical system in wide-angle mode according to the second embodiment of the present invention. Figure 7b This is a cross-sectional view of the zoom optical system in the intermediate mode according to the second embodiment of the present invention. Figure 7c This is a cross-sectional view of the zoom optical system in telephoto mode according to the second embodiment of the present invention.

[0214] Tables 5 and 6 below show the optical properties of the lenses included in the zoom optical system according to the second embodiment of the present invention, and Tables 7 and 8 show the König constants and aspherical coefficients of the lenses included in the zoom optical system according to the second embodiment of the present invention.

[0215] [Table 5]

[0216]

[0217] [Table 6]

[0218]

[0219] [Table 7]

[0220]

[0221]

[0222] [Table 8]

[0223] 112 -1.04649E-05 1.72342E-06 -1.48961E-07 6.64699E-09 -1.20780E-10 114 1.47494E-04 -1.55020E-05 9.79706E-07 -3.41161E-08 5.02655E-10 122 7.21283E-04 -9.02848E-05 6.72308E-06 -2.74655E-07 4.74041E-09 124 1.20570E-03 -1.76536E-04 1.52602E-05 -7.21973E-07 1.44392E-08 132 9.78776E-04 -1.69515E-04 1.73166E-05 -9.68051E-07 2.28904E-08 134 8.07028E-04 -1.62604E-04 1.96254E-05 -1.30684E-06 3.69850E-08 212 -3.83112E-04 7.58456E-05 -9.08334E-06 6.02223E-07 -1.69542E-08 214 2.49937E-04 -2.55435E-05 6.73466E-07 9.69288E-08 -6.51056E-09 222 5.19325E-04 -7.65402E-05 6.32520E-06 -2.27845E-07 3.96858E-10 224 1.74859E-03 -4.55420E-04 7.33745E-05 -6.62929E-06 2.56467E-07 312 3.91363E-04 4.46238E-06 -1.91223E-05 3.50743E-06 -2.06972E-07 314 3.18147E-03 -9.78027E-04 1.87213E-04 -2.04952E-05 9.88848E-07 322 -7.81585E-04 4.10557E-04 -1.14038E-04 1.60623E-05 -8.87521E-07 324 2.01002E-03 -8.62044E-04 2.16595E-04 -2.97120E-05 1.72112E-06 412 3.60334E-04 -6.07140E-05 6.27834E-06 -3.63061E-07 9.01067E-09 414 5.12950E-04 -7.65296E-05 7.04285E-06 -3.63357E-07 8.03899E-09 422 1.64405E-04 -1.77387E-05 1.16143E-06 -4.16072E-08 6.18248E-10 424 -7.05316E-05 1.16583E-05 -1.05354E-06 4.96495E-08 -9.41647E-10

[0224] refer to Figures 7a to 7c As per Tables 5 to 8, the zoom optical system includes a first lens group 100, a second lens group 200, a third lens group 300, and a fourth lens group 400 arranged sequentially from the object side to the image side. The first lens group 100 includes a first lens 110, a second lens 120, and a third lens 130 arranged sequentially from the object side to the image side. The second lens group 200 includes a fourth lens 210 and a fifth lens 220 arranged sequentially from the object side to the image side. The third lens group 300 includes a sixth lens 310 and a seventh lens 320 arranged sequentially from the object side to the image side. The fourth lens group 400 includes an eighth lens 410. In Table 5, thickness (mm) represents the distance from one lens surface to the next.

[0225] For example, the thickness corresponding to the object-side surface 112 of the first lens 110 represents the distance from the object-side surface 112 to the image-side surface 114 of the first lens 110. Specifically, the thickness corresponding to the object-side surface 112 of the first lens 110 represents 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.

[0226] The thickness corresponding to 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 thickness corresponding to 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.

[0227] The thickness corresponding to the image-side surface 134 of the third lens 130 represents the distance from the image-side surface 134 of the third lens 130 to the object-side surface 212 of the fourth lens 210. Specifically, the thickness corresponding to the image-side surface 134 of the third lens 130 represents the distance from the center of curvature of the image-side surface 134 of the third lens 130 to the center of curvature of the object-side surface 212 of the fourth lens 210.

[0228] In this case, since the second lens group 200 moves during the zoom from wide-angle mode to telephoto mode, the thickness of the image-side surface 134 corresponding to the third lens 130 can vary. The thickness of the image-side surface 134 corresponding to the third lens 130 can have a value between the shortest and longest distance. Referring to Table 5, the thickness of the image-side surface 134 corresponding to the third lens 130 in wide-angle mode can have the longest distance (6.89537). The thickness of the image-side surface 124 corresponding to the second lens 120 in intermediate mode can have a value between the shortest and longest distance (2.645292). The thickness of the image-side surface 124 corresponding to the second lens 120 in telephoto mode can have the shortest distance (0.202379). The thickness of the image-side surface 124 corresponding to the second lens 120 is the same as the thickness of the image-side surface 224 corresponding to the fifth lens 220 and the thickness of the image-side surface 324 corresponding to the seventh lens 320.

[0229] Referring to Table 5, it can be seen that the difference between the Abbe numbers of the fourth lens 210 and the fifth lens 220 included in the second lens group 200 is 10 or greater. Specifically, since the Abbe number of the fourth lens 210 is 71.68 and the Abbe number of the fifth lens 220 is 23.53, the difference between the Abbe numbers of the two lenses is approximately 48, and thus it can be seen that the difference is 10 or greater.

[0230] Referring to Table 5, it can be seen that either the fourth lens 210 or the fifth lens 220 included in the second lens group 200 is a glass lens. Specifically, the fourth lens 210 is a glass-molded lens, and the fifth lens 220 is a plastic lens. Similarly, either the eighth lens 410 or the ninth lens 420 included in the fourth lens group 400 can also be a glass lens. Specifically, the eighth lens 410 can be a glass-molded lens, and the ninth lens 420 can be a plastic lens.

[0231] Referring to Table 6, each surface of the first lens 110 to the ninth lens 420 can be formed as convex or concave.

[0232] The first lens 110 may be a lens whose object-side surface 112 is convex to the object side. The first lens 110 may also be a lens whose image-side surface 114 is convex to the object side. The second lens 120 may be a lens whose object-side surface 122 is convex to the object side. The second lens 120 may also be a lens whose image-side surface 124 is convex to the object side. The third lens 130 may be a lens whose object-side surface 132 is concave to the object side. The third lens 130 may also be a lens whose image-side surface 134 is convex to the object side.

[0233] The fourth lens 210 can be a lens whose object-side surface 212 is convex to the object side. The fourth lens 210 can also be a lens whose image-side surface 214 is concave to the object side. The fifth lens 220 can be a lens whose object-side surface 222 is concave to the object side. The fifth lens 220 can also be a lens whose image-side surface 224 is concave to the object side. Simultaneously, when the distance between the first lens group 100 and the second lens group 200 is at its minimum (i.e., in telephoto mode), the center of curvature of the object-side surface 212 of the fourth lens 210 can be positioned closer to the image side than the two ends of the image-side surface 134 of the third lens 130.

[0234] The sixth lens 310 may be a lens whose object-side surface 312 convexes towards the object side. The sixth lens 310 may be a lens whose image-side surface 314 convexes towards the object side. The seventh lens 320 may be a lens whose object-side surface 322 convexes towards the object side. The seventh lens 320 may be a lens whose image-side surface 324 convexes towards the object side.

[0235] The eighth lens 410 may be a lens whose object-side surface 412 is concave to the object side. The eighth lens 410 may be a lens whose image-side surface 414 is concave to the object side. The ninth lens 420 may be a lens whose object-side surface 422 is convex to the object side. The ninth lens 420 may be a lens whose image-side surface 424 is concave to the object side.

[0236] refer to Figure 7a When the distance between the first lens group 100 and the second lens group 200 is d1a, the distance between the second lens group 200 and the third lens group 300 is d2a, and the distance between the third lens group 300 and the fourth lens group 400 is d3a, the zoom optical system can enter wide-angle mode (e.g., 3x magnification). That is, when the distance between the center of curvature of the image-side surface 134 of the third lens 130 and the center of curvature of the object-side surface 212 of the fourth lens 210 is d1a, the distance between the center of curvature of the image-side surface 224 of the fifth lens 220 and the center of curvature of the object-side surface 312 of the sixth lens 310 is d2a, and the distance between the center of curvature of the image-side surface 324 of the seventh lens 320 and the center of curvature of the object-side surface 412 of the eighth lens 410 is d3a, the zoom optical system can enter wide-angle mode.

[0237] exist Figure 7bIn this system, the zoom optical system can enter an intermediate mode when the distance between the first lens group 100 and the second lens group 200 is d1b, the distance between the second lens group 200 and the third lens group 300 is d2b, and the distance between the third lens group 300 and the fourth lens group 400 is d3b. Specifically, the zoom optical system can enter an intermediate mode when the distance between the center of curvature of the image-side surface 134 of the third lens 130 and the center of curvature of the object-side surface 212 of the fourth lens 210 is d1b, the distance between the center of curvature of the image-side surface 224 of the fifth lens 220 and the center of curvature of the object-side surface 312 of the sixth lens 310 is d2b, and the distance between the center of curvature of the image-side surface 324 of the seventh lens 320 and the center of curvature of the object-side surface 412 of the eighth lens 410 is d3b.

[0238] exist Figure 7c In this zoom optical system, when the distance between the first lens group 100 and the second lens group 200 is d1c, the distance between the second lens group 200 and the third lens group 300 is d2c, and the distance between the third lens group 300 and the fourth lens group 400 is d3c, the zoom optical system can enter telephoto mode (e.g., 10x magnification). That is, when the distance between the center of curvature of the image-side surface 134 of the third lens 130 and the center of curvature of the object-side surface 212 of the fourth lens 210 is d1c, the distance between the center of curvature of the image-side surface 224 of the fifth lens 220 and the center of curvature of the object-side surface 312 of the sixth lens 310 is d2c, and the distance between the center of curvature of the image-side surface 324 of the seventh lens 320 and the center of curvature of the object-side surface 412 of the eighth lens 410 is d3c, the zoom optical system can enter telephoto mode.

[0239] The distance between adjacent lens groups can change when changing the magnification from wide-angle mode to telephoto mode.

[0240] The distance between the first lens group 100 and the second lens group 200 can continuously change from d1a to d1b and from d1b to d1c. Referring to Table 1, in wide-angle mode, the distance d1a between the first lens group 100 and the second lens group 200 is 6.89537 mm. In intermediate mode, the distance d1b between the first lens group 100 and the second lens group 200 is 2.645292 mm. In telephoto mode, the distance d1c between the first lens group 100 and the second lens group 200 is 0.202379 mm. As described above, during the continuous change of magnification from wide-angle mode to intermediate mode and from intermediate mode to telephoto mode, the distance between the first lens group 100 and the second lens group 200 can continuously change from 6.89537 mm to 2.645292 mm and from 2.645292 mm to 0.202379 mm. In other words, as the magnification is continuously changed from wide-angle mode to telephoto mode, the distance between the first lens group 100 and the second lens group 200 can gradually decrease (d1a>d1b>d1c). That is, as the magnification is continuously changed from wide-angle mode to telephoto mode, the increase in the distance between the first lens group 100 and the second lens group 200 can gradually decrease.

[0241] The distance between the second lens group 200 and the third lens group 300 can continuously change from d2a to d2b and from d2b to d2c. Referring to Table 5, in wide-angle mode, the distance (d2a) between the second lens group 200 and the third lens group 300 is 1.185986 mm. In intermediate mode, the distance (d2b) between the second lens group 200 and the third lens group 300 is 1.189047 mm. In telephoto mode, the distance (d1c) between the second lens group 200 and the third lens group 300 is 2.011179 mm. As described above, during the continuous change of magnification from wide-angle mode to intermediate mode and from intermediate mode to telephoto mode, the distance between the second lens group 200 and the third lens group 300 can continuously change from 1.185986 mm to 1.189047 mm and from 1.189047 mm to 2.011179 mm. In other words, during the continuous change of magnification from wide-angle mode to telephoto mode, the distance between the second lens group 200 and the third lens group 300 can decrease (d2a>d2b>d2c). In this case, during the continuous change of magnification from wide-angle mode to telephoto mode, the increase in the distance between the second lens group 200 and the third lens group 300 can increase.

[0242] The distance between the third lens group 300 and the fourth lens group 400 may continuously vary from d3a to d3b and from d3b to d3c. With reference to Table 5, in the wide-angle mode, the distance (d3a) between the third lens group 300 and the fourth lens group 400 is 1.458434 [mm]. In the intermediate mode, the distance (d3b) between the third lens group 300 and the fourth lens group 400 is 5.70545 [mm]. In the telephoto mode, the distance (d3c) between the third lens group 300 and the fourth lens group 400 is 7.326231 [mm]. As described above, during the process of continuously changing the magnification from the wide-angle mode to the intermediate mode and from the intermediate mode to the telephoto mode, the distance between the third lens group 300 and the fourth lens group 400 may continuously vary from 1.458434 [mm] to 5.70545 [mm] and from 5.70545 [mm] to 7.326231 [mm]. That is, during the process of continuously changing the magnification from the wide-angle mode to the telephoto mode, the distance between the third lens group 300 and the fourth lens group 400 may gradually increase (d3a<d3b<d3c). However, during the process of continuously changing the magnification from the wide-angle mode to the telephoto mode, the increase in the distance between the third lens group 300 and the fourth lens group 400 may gradually decrease.

[0243] As described above, the moving speed of the second lens group 200 and the moving speed of the third lens group 300 may be different from each other.

[0244] By moving the second lens group 200 and the third lens group 300, the magnification of the zoom optical system may be continuously changed from a magnification of 5x to a magnification of 10x.

[0245] Then, reference will be made to Figures 8a to 8c to describe the simulation results of longitudinal spherical aberration, astigmatic field curves, and distortion of the zoom optical system according to the second embodiment of the present invention. The longitudinal spherical aberration refers to the longitudinal spherical aberration according to each wavelength, the astigmatic field curves refer to the aberration properties of the tangential plane and the sagittal plane according to the height of the image surface, and the distortion refers to the distortion degree according to the height of the image surface.

[0246] Figure 8a is a diagram showing the longitudinal spherical aberration, astigmatic field curves, and distortion of light with wavelengths of 435 nm, 486 nm, 546 nm, 587 nm, and 656 nm in the optical system in the wide-angle mode according to the second embodiment.

[0247] Figure 8b is a diagram showing the longitudinal spherical aberration, astigmatic field curves, and distortion of light with wavelengths of 435 nm, 486 nm, 546 nm, 587 nm, and 656 nm in the optical system in the intermediate mode according to the second embodiment.

[0248] Figure 8c It is a graph showing the longitudinal spherical aberration, astigmatism curves, and distortion of light at wavelengths of 435nm, 486nm, 546nm, 587nm, and 656nm in the optical system of the telephoto mode according to the second embodiment.

[0249] refer to Figures 8a to 8c It can be seen that regardless of the wavelength, the longitudinal spherical aberration from the center to the edge of the image sensor is in the range of -0.05 mm to 0.1 mm. Specifically, in wide-angle mode, the longitudinal spherical aberration is in the range of approximately -0.03 mm to 0.05 mm, and in intermediate mode, it is in the range of -0.02 mm to 0.1 mm. In telephoto mode, the longitudinal spherical aberration is in the range of approximately -0.05 mm to 0.05 mm, but under light with a wavelength of 656 nm, the longitudinal spherical aberration exceeds 0.1 mm.

[0250] refer to Figures 8a to 8c It can be seen that the astigmatism curve from the center to the edge of the image sensor ranges from -0.05 mm to 0.01 mm, independent of wavelength. Specifically, it can be seen that in wide-angle mode, the astigmatism curve ranges from approximately -0.02 mm to 0 mm, and in intermediate mode, the astigmatism curve ranges from -0.02 mm to 0.01 mm. It can be seen that in telephoto mode, the astigmatism curve ranges from approximately -0.05 mm to 0 mm.

[0251] refer to Figures 8a to 8c It can be seen that regardless of the wavelength, the distortion from the center to the edge of the image sensor is in the range of -2.5% to 0%. Specifically, it can be seen that in wide-angle mode, the distortion is in the range of approximately -1% to 0%, and in intermediate mode, the distortion is in the range of -1.5% to 0%. It can be seen that in telephoto mode, the distortion is in the range of -2.5% to 0%.

[0252] Then, refer to Figures 9a to 9c The simulation results of the modulation transfer function (MTF) of the zoom optical system according to the second embodiment of the present invention are described. MTF is one of the performance measurement methods for optical systems.

[0253] Figure 9a This is a diagram illustrating the diffraction MTF in the optical system in wide-angle mode according to the second embodiment. Figure 9b This is a diagram showing the diffraction MTF of the optical system in the intermediate mode according to the second embodiment. Figure 9cThis is a diagram illustrating the diffraction MTF in the optical system of the telephoto mode according to the second embodiment.

[0254] refer to Figures 9a to 9c It can be seen that the zoom optical system according to the embodiment of the present invention has a value close to the diffraction limit near the defocus position in each of the wide-angle mode, intermediate mode and telephoto mode, which is in the range of -0.01 to 0.01 [mm].

[0255] Figure 10 This is a diagram showing the relative illumination of a zoom optical system according to a second embodiment of the present invention.

[0256] refer to Figure 10 It can be seen that, in the zoom optical system according to the second embodiment of the present invention, the relative illumination value is 50% or greater in all areas of the wide-angle mode (zoom position 1), intermediate mode (zoom position 2), and telephoto mode (zoom position 3). It can also be seen that the relative illumination value is 80% or greater in all areas of the intermediate and telephoto modes, and even in the case of the wide-angle mode, the relative illumination value is 80% or greater in the range of 0 to 1.8 [mm].

[0257] As described above with reference to the embodiments, it can be seen that the optical system according to the embodiments of the present invention has high aberration properties.

[0258] Meanwhile, the zoom optical system according to embodiments of the present invention can be applied to a camera module. A camera module including a zoom optical system according to an embodiment of the present invention can be installed in a portable terminal and applied to the portable terminal together with a main camera module. The camera module according to an embodiment of the present invention may include an image sensor, a filter disposed on the image sensor, and a zoom optical system disposed on the filter. The zoom optical system according to an embodiment of the present invention may include the aforementioned first lens group 100, second lens group 200, third lens group 300, and fourth lens group 400. The portable terminal equipped with the camera module including the zoom optical system according to an embodiment of the present invention can be a smartphone, tablet PC, laptop computer, or personal digital assistant (PDA), etc. The optical system according to an embodiment of the present invention can be applied to a camera module.

[0259] Figure 11 This is a view of a portion of a portable terminal that uses a camera module according to an embodiment of the present invention.

[0260] refer to Figure 11 A camera module including a zoom optical system 1000 according to an embodiment of the present invention can be installed in a portable terminal and can be used together with a main camera module 1100 in a portable terminal.

[0261] The zoom optical system 1000 according to an embodiment of the present invention may include a first lens group 100, a second lens group 200, a third lens group 300, and a fourth lens group 400 as described above. Due to the thickness limitation of the portable terminal, the first lens group 100, the second lens group 200, the third lens group 300, and the fourth lens group 400 may be arranged sequentially in the lateral direction of the portable terminal. For this purpose, as described above, a right-angle prism may be further disposed in front of the first lens group 100. When the zoom optical system is disposed in the thickness direction of the portable terminal, that is, the lens surfaces of the lenses included in the zoom optical system are arranged in the thickness direction of the portable terminal, the diameter of the lenses included in the zoom optical system can be reduced to reduce the thickness of the portable terminal. Therefore, even in a portable terminal, a zoom optical system capable of continuously adjusting the magnification by moving the lenses can be installed.

[0262] The portable terminal equipped with a camera module including a zoom optical system according to an embodiment of the present invention can be a smartphone, tablet PC, laptop computer, or PDA, etc.

[0263] While the present invention has been described above primarily with reference to embodiments, those skilled in the art should understand that the present invention is not limited to these embodiments, but rather that the embodiments are merely exemplary, and various modifications and applications not shown above can be made without departing from the essential characteristics of these embodiments. For example, components specifically described in the embodiments can be modified and implemented. Furthermore, it should be understood that differences related to modifications and applications fall within the scope of the invention as defined by the appended claims.

Claims

1. A zoom optical system comprising a first lens group, a second lens group, a third lens group, and a fourth lens group arranged sequentially and adjacently in a direction from the object side to the image side, without any other intervening lens groups. in, The first lens group includes a first lens, a second lens, and a third lens arranged sequentially from the object side. The object-side surface of the first lens convexes towards the object side, and the image-side surface of the first lens is concave towards the object side. Wherein, the object-side surface of the second lens convexes towards the object side, and the image-side surface of the second lens convexes towards the object side, and The object-side surface of the third lens is concave to the object side, and the image-side surface of the third lens is convex to the object side. The first lens group and the fourth lens group are fixed. The second lens group and the third lens group are movable, and The effective focal length (EFL) in telephoto mode is defined by the following expression. ， Here, EFL tele It is the EFL of the zoom optical system in the telephoto mode, and H imageD It is half the diagonal length of the pixel region of the image sensor.

2. The zoom optical system according to claim 1, wherein: The first lens group includes three or more lenses; The second lens group includes two or more lenses; The third lens group includes two or more lenses; The fourth lens group includes a lens; and The second lens group and the third lens group each have fewer lenses than the first lens group.

3. The zoom optical system according to claim 1, wherein, The EFL in wide-angle mode is defined by the following expression. ， Here, EFL wide It is the EFL of the zoom optical system in the wide-angle mode, and H imageD It is half the diagonal length of the pixel region of the image sensor.

4. The zoom optical system according to claim 1, wherein, When zooming from wide-angle mode to telephoto mode, the travel distance of the second lens group is defined by the following expression. ， Here, TTL (Total Track Length) is the distance from the surface of the image sensor to the first surface of the zoom optical system, and STROKE2 is the travel distance of the second lens group.

5. The zoom optical system according to claim 1, wherein, When zooming from wide-angle mode to telephoto mode, the travel distance of the third lens group is defined by the following expression. ， Here, TTL is the distance from the surface of the image sensor to the first surface of the zoom optical system, and STROKE3 is the travel distance of the third lens group.

6. The zoom optical system according to claim 1, wherein: The first lens group includes multiple lenses; Among the plurality of lenses included in the first lens group, the lens disposed on the image side has positive refractive power; and Among the plurality of lenses included in the first lens group, the lens disposed on the object side has negative refractive power.

7. The zoom optical system according to claim 5, wherein: The second lens group includes at least two lenses; and The at least two lenses included in the second lens group have Abbe numbers defined by the following expression: ， Here, ABBE4 is the Abbe number of the lens disposed on the object side of the two lenses included in the second lens group, and ABBE5 is the Abbe number of the lens disposed on the image side of the two lenses included in the second lens group.

8. The zoom optical system according to claim 6, wherein, The second lens group includes at least one of the following: Glass lenses; and Plastic lens.

9. The zoom optical system according to claim 1, wherein, The maximum diameter of the plurality of lenses included in the first lens group and the fourth lens group, and the maximum diameter of the plurality of lenses included in the second lens group and the third lens group are defined by the following expressions. ， Here, APER fix It is the maximum diameter of the lenses included in the first lens group and the fourth lens group, which are fixed groups, and APER mov It is the maximum diameter of the lens included in the second lens group and the third lens group, which are moving groups.

10. The zoom optical system according to claim 1, wherein, The principal ray angle (CRA) is greater than -5° and less than 5°.

11. The zoom optical system according to claim 1, wherein, The second lens group and the third lens group have different moving speeds.

12. The zoom optical system according to claim 1, wherein, The filter and the image sensor are sequentially positioned at the rear end of the fourth lens group.

13. The zoom optical system according to claim 7, wherein, At least one of the lenses included in the first to fourth lens groups has an upper portion and a lower portion, the upper portion and the lower portion having partially cut ribs and an effective diameter, or having only cut ribs without cutting the effective diameter.

14. The zoom optical system according to claim 1, wherein, The second lens group and the third lens group include lenses in which a value of 1 is obtained by dividing the length of the major axis of the effective diameter by the length of the minor axis of the effective diameter.

15. The zoom optical system according to claim 1, wherein, At least one of the lenses included in the first to fourth lens groups is a D-cut lens.

16. The zoom optical system according to claim 8, wherein, The second lens group includes at least one glass lens, and one of the two lenses included in the second lens group is a glass lens disposed on the object side.

17. The zoom optical system according to claim 1, wherein, The aperture of each of the second and third lens groups is smaller than the aperture of each of the first and fourth lens groups.

Images