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 an object side to an image side, a first lens group, a second lens group, and a third lens group, wherein the second lens group and the third lens group are movable, and an effective focal length (EFL) at a wide angle is defined by the following equation: EFLwide = H / 2 * tan (arctan (H / 2 / D50) - arctan (H / 2 / D50wide)) where EFLwide refers to the effective focal length of the zoom optical system at the wide angle, H refers to the half value of the diagonal length of an image sensor pixel area, D50 refers to the half value of the diagonal length of an image sensor pixel area at a standard angle, and D50wide refers to the half value of the diagonal length of an image sensor pixel area at the wide angle. imageD is the half value of the 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 advancement of camera module performance embedded in portable terminals, autofocus functionality is also required for these modules.

[0003] To enable autofocus in the camera module of a portable terminal, the magnification can be increased through digital processing during the conversion of external light into digital images or digital video. Therefore, zooming can be performed only at predetermined magnifications such as 1x, 3x, and 5x, but as the magnification increases, there is a problem of reduced resolution and digital degradation.

[0004] Meanwhile, to enable autofocus in camera modules of portable devices, techniques are being explored that allow lenses to move to adjust the distance between the lens and the image sensor. However, designing an optical system that can move within a confined space in a portable device is not easy. Summary of the Invention

[0005] Technical issues

[0006] The present invention aims to provide a zoom optical system and a camera module including the zoom optical system.

[0007] The objectives to be addressed in this embodiment are not limited to those described above, but also include objectives and effects that can be determined by the objectives and solutions described below and the embodiments.

[0008] Technical solution

[0009] The zoom optical system according to an embodiment of the present invention includes a first lens group, a second lens group, and a third lens group arranged sequentially from the object side to the image side, wherein the second lens group and the third lens group are movable, and the effective focal length (EFL) at wide angle is defined by the following formula:

[0010]

[0011] Among them, EFL wide H refers to the effective focal length of a zoom optical system at wide angles. imageD It refers to half the diagonal length of the pixel area of ​​the image sensor.

[0012] The first lens group may include three or fewer lenses, the second lens group may include two or fewer lenses, and the third lens group may include two or fewer lenses.

[0013] The effective focal length at long focal lengths can be defined by the following formula.

[0014]

[0015] Among them, EFL tele It can refer to the effective focal length of a zoom optical system at long focal lengths, H. imageD It can refer to half the diagonal length of the pixel area of ​​an image sensor.

[0016] During the zoom process from wide-angle to telephoto, the movement stroke of the second lens group can be defined by the following formula:

[0017]

[0018] Here, TTL can refer to the distance from the surface of the image sensor to the first surface of the zoom optical system, and STROKE2 can refer to the movement stroke of the second lens group.

[0019] During the zoom process from wide-angle to telephoto, the movement stroke of the third lens group can be defined by the following formula:

[0020]

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

[0022] Each of the first lens group, the second lens group, and the third lens group may include a plastic lens.

[0023] The maximum diameter of the multiple lenses included in the first lens group, as well as the maximum diameter of the multiple lenses included in the second and third lens groups, can be defined by the following formula.

[0024]

[0025] Among them, APER fix It can refer to the maximum diameter of the lenses included in the first lens group of the fixed group, APER. mov It can refer to the maximum diameter of the lenses included in the second and third lens groups, which are part of the moving group.

[0026] The chief ray angle (CRA) can be greater than -20° and less than -10°.

[0027] The zoom optical system may further include a right-angle prism positioned in front of the first lens group.

[0028] The zoom optical system may further include a dummy lens positioned behind the third lens group.

[0029] The effective diameter of the virtual lens can be greater than the effective diameter of the first lens group.

[0030] According to another embodiment of the present invention, a zoom optical system includes a first lens group, a second lens group, and a third lens group arranged sequentially from the object side to the image side, wherein the second lens group and the third lens group are movable, and the effective focal length at telephoto is defined by the following formula.

[0031]

[0032] Among them, EFL tele H refers to the effective focal length of a zoom optical system at long focal lengths. imageD It refers to half the diagonal length of the pixel area of ​​the image sensor.

[0033] According to another embodiment of the present invention, a zoom optical system includes a first lens group, a second lens group, and a third lens group arranged sequentially from the object side to the image side, wherein the first lens group is fixed, the second lens group and the third lens group are movable, the second lens group performs the zoom function, and the third lens group performs the focusing function. The movement stroke of the second lens group is less than 2 mm, and when the distance from the surface of the image sensor to the first surface of the zoom optical system is less than 17 mm, the zoom optical system corresponds to the movement stroke (less than 2 mm) of the second lens group, as defined by the following formula.

[0034]

[0035] Among them, EFL tele EFL refers to the effective focal length at long focal lengths. wide This refers to the effective focal length in wide-angle mode.

[0036] According to another embodiment of the present invention, a zoom optical system includes a first lens group, a second lens group, and a third lens group arranged sequentially from the object side to the image side, wherein the first lens group is fixed, the second lens group and the third lens group are movable, the second lens group performs the zoom function, and the third lens group performs the focusing function, with a focal length greater than 14mm at telephoto and an F number (aperture number) less than 3 at telephoto.

[0037] According to another embodiment of the present invention, a zoom optical system includes a first lens group, a second lens group, and a third lens group arranged sequentially from the object side to the image side, wherein the first lens group is fixed, the second lens group and the third lens group are movable, the second lens group performs the zoom function, and the third lens group performs the focusing function, with a focal length of less than 10mm at wide angles and an F number of less than 2.3 at wide angles.

[0038] According to another embodiment of the present invention, a zoom optical system includes a first lens group, a second lens group, and a third lens group arranged sequentially from the object side to the image side, wherein the first lens group is fixed, the second lens group and the third lens group are movable, the second lens group performs a zoom function, the third lens group performs a focusing function, and the diagonal length of the pixel area of ​​the image sensor disposed behind the third lens group is greater than 6 mm.

[0039] Beneficial effects

[0040] According to embodiments of the present invention, an optical system capable of zooming at high magnification in addition to low 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

[0041] Figure 1 A zoom optical system according to an embodiment of the present invention is shown.

[0042] Figure 2 This is a view used to describe a lens employing D-cutting technology according to an embodiment of the present invention.

[0043] Figure 3a This is a cross-sectional view of a zoom optical system according to a first embodiment of the present invention at a wide angle.

[0044] Figure 3b This is a cross-sectional view of the zoom optical system according to the first embodiment of the present invention in intermediate mode.

[0045] Figure 3c This is a cross-sectional view of a zoom optical system according to a first embodiment of the present invention at a telephoto focal length.

[0046] Figure 4a This is a measurement diagram of longitudinal spherical aberrations, astigmatic field cues, and distortion of light at wide angles for wavelengths of 435 nm, 486 nm, 546 nm, 587 nm, and 656 nm in an optical system according to a first embodiment of the present invention.

[0047] Figure 4b This is a measurement diagram of longitudinal spherical aberration, scattering curve, and distortion of light at wavelengths of 435 nm, 486 nm, 546 nm, 587 nm, and 656 nm in an optical system in intermediate mode according to a first embodiment of the present invention.

[0048] Figure 4cThis is a measurement diagram of longitudinal spherical aberration, astigmatism curve, and distortion of light at long focal length for wavelengths of 435 nm, 486 nm, 546 nm, 587 nm, and 656 nm in an optical system according to a first embodiment of the present invention.

[0049] Figure 5a This is a diagram of the diffraction modulation transfer function (MTF) of the optical system according to an embodiment at a wide angle.

[0050] Figure 5b This is a diffraction MTF diagram of the optical system according to an embodiment at long focal length.

[0051] Figure 6a This is a cross-sectional view of a zoom optical system according to a second embodiment of the present invention at a wide angle.

[0052] Figure 6b This is a cross-sectional view of a zoom optical system according to a second embodiment of the present invention in intermediate mode.

[0053] Figure 6c This is a cross-sectional view of a zoom optical system according to a second embodiment of the present invention at a telephoto focal length.

[0054] Figure 7a This is a measurement diagram of longitudinal spherical aberration, scattering curve, and distortion of light at a wide angle for wavelengths of 435 nm, 486 nm, 546 nm, 587 nm, and 656 nm in an optical system according to a second embodiment of the present invention.

[0055] Figure 7b This is a graph showing the longitudinal spherical aberration, scattering curve, and distortion curves of light with wavelengths of 435nm, 486nm, 546nm, 587nm, and 656nm in an optical system with wavelengths of 435nm, 486nm, 546nm, 587nm, and 656nm in the intermediate measurement mode according to the second embodiment of the present invention.

[0056] Figure 7c This is a graph showing the longitudinal spherical aberration, scattering curve, and distortion of light with wavelengths of 435nm, 486nm, 546nm, 587nm, and 656nm in an optical system under telephoto lens according to the second embodiment of the present invention.

[0057] Figure 8a This is a diffraction MTF diagram of the optical system according to an embodiment at a wide angle.

[0058] Figure 8b This is a diffraction MTF diagram of the optical system according to an embodiment at long focal length.

[0059] Figure 9a This is a cross-sectional view of a zoom optical system according to a third embodiment of the present invention at a wide angle.

[0060] Figure 9b This is a cross-sectional view of a zoom optical system according to a third embodiment of the present invention in intermediate mode.

[0061] Figure 9c This is a cross-sectional view of a zoom optical system according to a third embodiment of the present invention at a telephoto focal length.

[0062] Figure 10a This is a graph showing the longitudinal spherical aberration, scattering curve, and distortion of light with wavelengths of 435nm, 486nm, 546nm, 587nm, and 656nm in an optical system with a wide-angle field of measurement according to the third embodiment of the present invention.

[0063] Figure 10b This is a measurement diagram of longitudinal spherical aberration, scattering curve, and distortion of light at wavelengths of 435 nm, 486 nm, 546 nm, 587 nm, and 656 nm in an optical system in intermediate mode according to a third embodiment of the present invention.

[0064] Figure 10c This is a measurement diagram of longitudinal spherical aberration, astigmatism curve, and distortion of light at long focal length for wavelengths of 435 nm, 486 nm, 546 nm, 587 nm, and 656 nm in an optical system according to a third embodiment of the present invention.

[0065] Figure 11a This is a diffraction MTF diagram of the optical system according to an embodiment at a wide angle.

[0066] Figure 11b This is a diffraction MTF diagram of the optical system according to an embodiment at long focal length.

[0067] Figure 12 This is a diagram illustrating a zoom optical system according to an embodiment of the present invention.

[0068] Figure 13 This is a diagram showing a portion of a portable terminal that incorporates a camera module according to an embodiment of the present invention. Detailed Implementation

[0069] In the following, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0070] However, the technical concept of the present invention is not limited to the specific embodiments to be described, but can be implemented in various forms, and one or more components in the embodiments can be selectively combined and substituted within the scope of the technical concept of the present invention.

[0071] Furthermore, unless specifically defined and described, the terms (including technical and scientific terms) used in embodiments of the present invention may be interpreted as meanings commonly understood by those skilled in the art, and commonly used terms (e.g., terms defined in dictionaries) may be understood taking into account their contextual meaning in the relevant field.

[0072] Furthermore, the terminology used in the embodiments of the present invention is for describing the embodiments of the present invention only and is not intended to be limiting.

[0073] 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 more) of A, B and C", it may include at least one of all combinations that can be combined with A, B and C.

[0074] In addition, the terms first, second, A, B, (a), (b), etc., can be used to describe the components of embodiments of the present invention.

[0075] These terms are provided only to distinguish components from other components, and the nature, order, sequence, etc., of components are not limited by these terms.

[0076] Furthermore, when a component is described as being “connected,” “joined,” or “engaged” to another component, the component may include not only cases where it is directly connected, joined, or engaged to another component, but also cases where the component is directly connected, joined, or engaged to another component through another component between the component and the other component.

[0077] Furthermore, when a component is described as being formed "above" or "below" another component, the terms "above" or "below" include cases where the two components are in direct contact with each other or cases where one or more components are (indirectly) disposed between the two components. Additionally, when a component is described as being disposed "above or below" another component, such a description can include cases where the component is disposed on the upper or lower side relative to the other component.

[0078] Figure 1 A zoom optical system according to an embodiment of the present invention is shown.

[0079] Reference Figure 1 According to an embodiment of the present invention, a zoom optical system includes a first lens group 100, a second lens group 200, and a third lens group 300 arranged sequentially from the object side to the image side. A right-angle prism may be further disposed in front of 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, and a third lens group 300 arranged sequentially from the object side to the image side.

[0080] According to an 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 or fewer lenses. When the first lens group 100 includes one or two lenses, it may be difficult to correct the resolution at maximum magnification, and when the first lens group 100 includes three or more lenses, the overall size of the zoom optical system may increase. Therefore, the first lens group 100 preferably includes three lenses.

[0081] 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.

[0082] 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 preferably includes two lenses.

[0083] The second lens group 200 is movable. Multiple lenses included in the second lens group 200 can move together along the central axis of the lens. Two lenses included in the second lens group 200 can 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 preferably includes two lenses. The focal length can be continuously adjusted as the second lens group 200 moves. The magnification can be continuously adjusted as the second lens group 200 moves. Therefore, the second lens group 200 can be used as a zoom group.

[0084] 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. 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.

[0085] The third lens group 300 is movable. Multiple lenses included in the third lens group 300 can move together along the central axis of the lens. Two lenses included in the third lens group 300 can move 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 preferably includes two lenses. The focal point can be adjusted as the third lens group 300 moves. The third lens group 300 can be used as a focusing group.

[0086] According to an embodiment of the present invention, the filter 20 and the image sensor 10 can be arranged sequentially behind the third lens group 300. Here, the filter 20 can be an infrared (IR) filter. Therefore, the filter 20 can block near-IR light (e.g., light with wavelengths of 700 nm to 1100 nm) from entering the camera module. Furthermore, the image sensor 10 can be connected to a printed circuit board via wires.

[0087] The filter 20 may include a foreign object prevention filter and an IR filter arranged sequentially from the object side to the image side. When the filter 20 includes a foreign object prevention 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.

[0088] The magnification of the zoom optical system can change as the second lens group 200 and the third lens group 300 move. For example, the magnification of the zoom optical system can continuously increase or decrease between 3x and 5x as the second lens group 200 and the third lens group 300 move. According to this embodiment, the zoom optical system can have a magnification of 3x at a wide angle and 5x at a telephoto angle. Furthermore, the continuous increase or decrease in magnification does not mean that the magnification increases or decreases discontinuously in a numerical manner, but rather can refer to a linear increase or decrease.

[0089] Each of the second lens group 200 and the third lens group 300 can move independently. For example, when the wide-angle lens is changed to a telephoto lens, the distance between the second lens group 200 and the third lens group 300 can increase in the direction from the starting point of the movement (wide-angle) to the predetermined point and decrease in the direction from the predetermined point to the ending point of the movement (telephoto).

[0090] The effective focal length (EFL) of a zoom optical system according to an embodiment of the present invention will be described.

[0091] The effective focal length of a zoom optical system at telephoto can be represented by Equation 1 below.

[0092] [Formula 1]

[0093]

[0094] Among them, EFL tele H refers to the effective focal length of a zoom optical system at long focal lengths. imageD This refers to half the diagonal length of the pixel area of ​​an image sensor. The unit can be mm. The pixel area of ​​an image sensor can refer to the area within the image sensor where the light-receiving pixels are arranged. Alternatively, the pixel area can be the area removed from the entire area of ​​the image sensor, excluding the circuitry used to convert the received light into electrical signals, and, depending on the package housing, the area within the sensor itself.

[0095] According to one embodiment of the present invention, in a zoom optical system, at telephoto distances, the effective focal length can be greater than 14mm and the f-number can be less than 3. Half the diagonal length of the image sensor pixel region can be greater than 3mm. The diagonal length of the image sensor pixel region can be greater than 6mm.

[0096] The effective focal length of a zoom optical system at a wide angle can be expressed by Equation 2 below.

[0097] [Equation 2]

[0098]

[0099] Among them, EFL wide H refers to the effective focal length of a wide-angle focal length optical system. imageD It refers to half the diagonal length of the pixel area of ​​the image sensor.

[0100] According to one embodiment of the present invention, in a zoom optical system, at a wide angle, the effective focal length can be less than 10mm and the F-number can be less than 2.3. Half the diagonal length of the image sensor pixel region can be greater than 3mm. The diagonal length of the image sensor pixel region can be greater than 6mm.

[0101] The movement stroke of a zoom optical system according to an embodiment of the present invention will be described. The movement stroke can refer to the distance that the lens group can move through the drive unit.

[0102] The moving stroke of the second lens group 200 can be represented by the following formula 3.

[0103] [Formula 3]

[0104]

[0105] The total track length (TTL) can refer to the distance from the surface of the image sensor to the first surface of the zoom optical system. For example, TTL can refer to the distance from the surface of the first lens group 100 closest to the object side to the upper surface of the image sensor 10 where the incident light is received. In this specification, TTL and total length are interchangeable. STROKE2 can refer to the travel stroke of the second lens group 200. The unit can be mm. According to one embodiment of the present invention, in the zoom optical system, the TTL can be less than 17 mm, and the travel stroke of the second lens group 200 can be less than 2 mm.

[0106] With the distance from the surface of the image sensor to the first surface of the zoom optical system being less than 17 mm, the zoom optical system according to an embodiment of the present invention can correspond to the moving stroke of the second lens group (which is less than 2 mm), as defined by Equation 4 below.

[0107] [Formula 4]

[0108]

[0109] Among them, EFL tele EFL refers to the effective focal length at long focal lengths. wide This refers to the effective focal length in wide-angle mode.

[0110] The moving stroke of the third lens group 300 can be represented by the following formula 5.

[0111] [Formula 5]

[0112]

[0113] Here, TTL can refer to the distance from the surface of the image sensor to the first surface of the zoom optical system. STROKE3 can refer to the stroke of the third lens group 300. The unit can be mm.

[0114] When the travel stroke is large, the size of the drive unit used to move the second lens group 200 and the third lens group 300 increases, making it difficult to install the drive unit in a portable terminal. However, since the drive unit can be implemented in a smaller size by making the travel stroke about 1 / 6 to 1 / 5 compared to TTL, the camera module can be miniaturized.

[0115] The aperture of the lens in a zoom optical system according to an embodiment of the present invention will be described.

[0116] According to an 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 the first lens group 100. This can be represented by the following formula 6.

[0117] [Formula 6]

[0118]

[0119] Among them, APER fix This can refer to the maximum diameter of the lenses included in the first lens group 100. The first lens group 100 is a fixed group. (APER) mov This can refer to 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 in the first lens group 100, which is a fixed group, is the largest, APER... fix This can refer to the diameter of the first lens 110. When the diameter of the fourth lens 210, included in the second lens group 200 and the third lens group 300 as a movable group, is at its maximum, APER... mov It can refer to the diameter of the fourth lens 210.

[0120] By making the diameter of each of the second lens group 200 and the third lens group 300 smaller than the diameter of the first lens group 100, 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.

[0121] According to an embodiment of the present invention, each of the first lens group 100 to the third lens group 300 may include a plastic lens.

[0122] According to an embodiment of the present invention, in a zoom optical system, the principal ray angle (CRA) can be greater than -20° and less than -10°. The angle of light incident on the image sensor 10 (i.e., the image surface) can be greater than -20° and less than -10°. That is, the CRA of the zoom optical system according to an embodiment of the present invention can have any value between -20° and -10°.

[0123] Figure 2 This is a diagram illustrating a lens using the D-cutting technique according to an embodiment of the present invention.

[0124] Reference Figure 2 Each lens may include an effective diameter and ribs arranged around the effective diameter.

[0125] Figure 2 a shows a lens without the application of D-cutting technology. (e.g.) Figure 2 As shown in Figure a, when the D-cutting technique is not applied, the effective diameter and ribs of the lens do not need to be cut.

[0126] Figure 2 b illustrates a lens applying a D-cutting technique according to one embodiment. (See diagram for example.) Figure 2As shown in b, when applying the D-cutting technique according to one embodiment, a portion of the ribs in the lens can be cut. The effective diameter of the lens to which the D-cutting technique according to one embodiment is applied may not need to be cut.

[0127] Figure 2 c illustrates a lens employing a D-cutting technique according to another embodiment. Figure 2 As shown in c, when the D-cutting technique according to another embodiment is applied, a portion of the rib and a portion of the effective diameter can be cut in the lens.

[0128] Table 1 shows the major axis length, minor axis length, and effective diameter of a lens according to an embodiment of the present invention.

[0129] [Table 1]

[0130] First lens 6 5.55 5 Second lens 5.7 5.55 4.681 Third lens 5.6 5.25 4.6 Fourth lens 6 4.8 4.8 Fifth lens 5.8 4.8 4.315 Sixth lens 5.6 4.79 4.2 Seventh Lens 6.1 4.8 5

[0131] According to embodiments of the present invention, the plurality of lenses included in the first lens group 100 to the third lens group 300 may be lenses subjected to D-cutting technology. The first lens 110, the second lens 120, the third lens 130, the fourth lens 210, the fifth lens 220, the sixth lens 310, and the seventh lens 320 may be lenses subjected to D-cutting technology. Each of the plurality of lenses included in the first lens group 100 to the third lens group 300 may be a D-cut lens in which a portion of the upper portion and a portion of the lower portion are cut. Specifically, the first lens 110 may be a lens subjected to D-cutting technology where only a portion of the rib is cut. Referring to Table 2, the first lens 110 may have a major axis length of 6 mm, a minor axis length of 5.55 mm, and an effective diameter of 5 mm. In other words, since the major axis length is greater than the minor axis length, and the minor axis length is greater than the effective diameter length, the first lens 110 can be a lens using the D-cutting technique where the effective diameter is not cut but a portion of the rib is cut.

[0132] The second lens 120 can be a lens using a D-cutting technique where only a portion of the rib is cut. Referring to Table 2, the second lens 120 can have a major axis length of 5.7 mm, a minor axis length of 5.55 mm, and an effective diameter of 4.681 mm. That is, since the major axis length is greater than the minor axis length, and the minor axis length is greater than the effective diameter, the second lens 120 can be a lens using a D-cutting technique where only a portion of the rib is cut, without cutting the effective diameter.

[0133] The third lens 130 can be a lens using a D-cutting technique where only a portion of the rib is cut. Referring to Table 2, the third lens 130 can have a major axis length of 5.6 mm, a minor axis length of 5.25 mm, and an effective diameter of 4.6 mm. That is, since the major axis length is greater than the minor axis length, and the minor axis length is greater than the effective diameter, the third lens 130 can be a lens using a D-cutting technique where only a portion of the rib is cut, without cutting the effective diameter.

[0134] The fourth lens 210 can be a lens using a D-cutting technique where only a portion of the rib is cut. Referring to Table 2, the fourth lens 210 can have a major axis length of 6 mm, a minor axis length of 4.8 mm, and an effective diameter of 4.8 mm. That is, since the major axis length is greater than the minor axis length, and the minor axis length is equal to the effective diameter, the fourth lens 210 can be a lens using a D-cutting technique where only a portion of the rib is cut, without cutting the effective diameter.

[0135] The fifth lens 220 can be a lens using a D-cutting technique where only a portion of the rib is cut. Referring to Table 2, the fifth lens 220 can have a major axis length of 5.8 mm, a minor axis length of 4.8 mm, and an effective diameter of 4.315 mm. That is, since the major axis length is greater than the minor axis length, and the minor axis length is greater than the effective diameter, the fifth lens 220 can be a lens using a D-cutting technique where only a portion of the rib is cut, and the effective diameter is not cut.

[0136] The sixth lens 310 can be a lens that uses a D-cutting technique where only a portion of the rib is cut. Referring to Table 2, the sixth lens 310 can have a major axis length of 5.6 mm, a minor axis length of 4.79 mm, and an effective diameter of 4.2 mm. That is, since the major axis length is greater than the minor axis length, and the minor axis length is greater than the effective diameter, the sixth lens 310 can be a lens that uses a D-cutting technique where only a portion of the rib is cut, and the effective diameter is not cut.

[0137] The seventh lens 320 can be a lens using the D-cutting technique, where a portion of the applied rib and a portion of the effective diameter are cut. Referring to Table 2, the seventh lens 320 can have a major axis length of 6.1 mm, a minor axis length of 4.8 mm, and an effective diameter of 5 mm. That is, since the major axis length is greater than the minor axis length, and the minor axis length is less than the effective diameter, the seventh lens 320 can be a lens using the D-cutting technique, where a portion of the effective diameter and a portion of the rib are cut.

[0138] In the case of circular lenses, there is a problem that the lens volume increases due to the height in the vertical direction. However, as in the embodiments of the present invention, by applying D-cutting to the upper and lower portions of multiple lenses, the height in the vertical direction can be reduced, thereby reducing the lens volume.

[0139] Figure 3a This is a cross-sectional view of the zoom optical system according to the first embodiment of the present invention at a wide angle. Figure 3b This is a cross-sectional view of the zoom optical system according to the first embodiment of the present invention in intermediate mode. Figure 3c This is a cross-sectional view of a zoom optical system according to a first embodiment of the present invention at a telephoto focal length.

[0140] Tables 2 and 3 below show the optical characteristics of the lenses included in the zoom optical system according to the first embodiment of the present invention, and Tables 4 and 5 show the conic constants and aspherical coefficients of the lenses included in the zoom optical system according to the first embodiment of the present invention.

[0141] [Table 2]

[0142]

[0143] [Table 3]

[0144]

[0145] [Table 4]

[0146]

[0147] [Table 5]

[0148] 112 8.65E-06 -6.24E-06 1.30E-06 -1.28E-07 5.10E-09 114 -4.90E-06 -1.07E-05 2.87E-06 -3.17E-07 1.36E-08 122 4.80E-04 -9.62E-05 1.23E-05 -9.22E-07 3.07E-08 124 3.26E-03 -6.99E-04 9.11E-05 -6.66E-06 2.10E-07 132 3.86E-03 -9.21E-04 1.30E-04 -1.02E-05 3.40E-07 134 1.57E-03 -4.03E-04 6.22E-05 -5.34E-06 1.96E-07 212 5.11E-05 -1.34E-05 2.14E-06 -1.90E-07 7.03E-09 214 -9.82E-05 1.12E-05 -4.55E-07 -4.01E-08 3.92E-09 222 -5.24E-05 2.67E-06 7.90E-07 -1.75E-07 1.17E-08 224 8.21E-04 -3.18E-04 7.63E-05 -1.04E-05 6.08E-07 312 3.38E-04 -1.14E-04 2.39E-05 -2.83E-06 1.45E-07 314 -3.13E-04 4.95E-05 -4.63E-06 2.33E-07 -4.84E-09 322 -2.69E-03 5.48E-04 -7.24E-05 5.56E-06 -1.87E-07 324 -2.82E-04 1.66E-05 2.28E-06 -4.66E-07 2.40E-08

[0149] Reference Figures 3a to 3c As per Tables 2 to 5, the zoom optical system includes a first lens group 100, a second lens group 200, and a third lens group 300 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. In Table 2, thickness [mm] represents the distance from each lens surface to the next lens surface.

[0150] For example, the thickness described for the object-side surface 112 of the first lens 110 represents the distance from the object-side surface 112 of the first lens 110 to the image-side surface 114 of the first lens 110. Specifically, the thickness described for 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 of the first lens 110.

[0151] The thickness described for 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 described for 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.

[0152] The thickness described for 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 described for the image-side surface 134 of the third lens 130 represents 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.

[0153] In this case, the second lens group 200 moves during the zoom process from wide-angle to telephoto, thus the thickness recorded on the image-side surface 134 of the third lens 130 can change. The thickness recorded on the image-side surface 134 of the third lens 130 can have a value between the longest and shortest distances. Referring to Table 2, the thickness recorded on the image-side surface 134 of the third lens 130 can have a longest distance of 2.3098 at wide-angle. The thickness recorded on the image-side surface 134 of the third lens 130 can have a value between the shortest and longest distances in intermediate mode. The thickness recorded on the image-side surface 134 of the third lens 130 can have a shortest distance of 0.4 at telephoto. The thicknesses recorded on the image-side surfaces 224 of the fifth lens 220 and the seventh lens 320 are also equal.

[0154] Referring to Table 3, each surface of the first lens 110 to the seventh lens 320 can be made convex or concave.

[0155] The first lens 110 can be a lens whose object-side surface 112 convexes towards the object side. The first lens 110 can also be a lens whose image-side surface 114 is recessed towards the object side. The second lens 120 can be a lens whose object-side surface 122 is recessed towards the object side. The second lens 120 can also be a lens whose image-side surface 124 is recessed towards the object side. The third lens 130 can be a lens whose object-side surface 132 convexes towards the object side. The third lens 130 can also be a lens whose image-side surface 134 convexes towards the object side.

[0156] The fourth lens 210 can be a lens whose object-side surface 212 convexes towards the object side. The fourth lens 210 can also be a lens whose image-side surface 214 is recessed towards the object side. The fifth lens 220 can be a lens whose object-side surface 222 is recessed towards the object side. The fifth lens 220 can also be a lens whose image-side surface 224 convexes towards the object side.

[0157] Meanwhile, when the distance between the first lens group 100 and the second lens group 200 is the minimum distance (i.e. at telephoto), the center of curvature of the object-side surface 212 of the fourth lens 210 can be located closer to the image side than the two ends of the image-side surface 134 of the third lens 130.

[0158] The sixth lens 310 can be a lens with its object-side surface 312 recessed towards the object side. The sixth lens 310 can also be a lens with its image-side surface 314 recessed towards the object side. The seventh lens 320 can be a lens with its object-side surface 322 protruding towards the object side. The seventh lens 320 can also be a lens with its image-side surface 324 protruding towards the object side.

[0159] Reference Figure 3a 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 image sensor 10 is d3a, the zoom optical system can have a wide angle (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 image sensor 10 is d3a, the zoom optical system can have a wide angle.

[0160] exist Figure 3b In this zoom optical system, an intermediate mode is possible 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 image sensor 10 is d3b. That is, an intermediate mode is possible 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 image sensor 10 is d3b.

[0161] exist Figure 3c 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 image sensor 10 is d3c, the zoom optical system can have a telephoto lens (e.g., 5x 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 image sensor 10 is d3c, the zoom optical system can have a telephoto lens.

[0162] The distance between adjacent lens groups can be changed when changing the magnification from wide-angle to telephoto.

[0163] The distance between the first lens group 100 and the second lens group 200 can be changed from d1a to d1b and then to d1c. Referring to Table 2, at wide-angle, the distance d1a between the first lens group 100 and the second lens group 200 is 2.3098 mm. At telephoto, the distance d1c between the first lens group 100 and the second lens group 200 is 0.4 mm. As described above, during the process of changing the magnification from wide-angle to telephoto via intermediate mode, the distance between the first lens group 100 and the second lens group 200 can change from 2.3098 mm to 0.4 mm. That is, during the process of changing the magnification from wide-angle to telephoto, the distance between the first lens group 100 and the second lens group 200 can gradually decrease (d1a > d1b > d1c). During the process of changing the magnification from wide-angle to telephoto, the amount of increase in the distance between the first lens group 100 and the second lens group 200 can gradually decrease.

[0164] The distance between the second lens group 200 and the third lens group 300 can be changed from d2a to d2c via d2b. Referring to Table 2, the distance d2a between the second lens group 200 and the third lens group 300 is 2.1665mm at wide angle. At telephoto, the distance d1c between the second lens group 200 and the third lens group 300 is 1.4788mm. As described above, during the process of changing the magnification from wide angle to telephoto via intermediate mode, the distance between the second lens group 200 and the third lens group 300 can be changed from 2.1665mm to 1.4788mm. That is, during the process of changing the magnification from wide angle to telephoto, the distance between the second lens group 200 and the third lens group 300 can decrease (d2a > d2b > d2c). In this case, the amount of increase in the distance between the second lens group 200 and the third lens group 300 during the process of changing the magnification from wide angle to telephoto can gradually decrease.

[0165] The distance between the third lens group 300 and the image sensor 10 can be changed from d3a to d3b and then to d3c. Referring to Table 2, the distance d3a between the third lens group 300 and the image sensor 10 is 2.36 mm at wide-angle. At telephoto, the distance d3c between the third lens group 300 and the image sensor 10 is 4.95749 mm. As described above, the distance between the third lens group 300 and the image sensor 10 can change from 2.36 mm to 4.95749 mm as the magnification changes from wide-angle to telephoto via intermediate mode. The distance between the third lens group 300 and the image sensor 10 can gradually increase (d3a < d3b < d3c) as the magnification changes from wide-angle to telephoto. However, the amount of increase in the distance between the third lens group 300 and the image sensor 10 can gradually decrease as the magnification changes from wide-angle to telephoto.

[0166] The second lens group 200 and the third lens group 300 can have different moving speeds.

[0167] As the second lens group 200 and the third lens group 300 move, the magnification of the zoom optical system can be continuously adjusted from 3x to 5x.

[0168] Next, we will refer to Figures 4a to 4c The simulation results of longitudinal spherical aberration, astigmatism curve, and distortion of a zoom optical system according to a first embodiment of the present invention are described. Longitudinal spherical aberration refers to the longitudinal spherical aberration per wavelength, astigmatism curve refers to the aberration characteristics of the tangential plane and sagittal plane of the image surface height, and distortion refers to the degree of distortion of the image surface height.

[0169] Figure 4aIt is a graph measuring the longitudinal spherical aberration, astigmatism curve, and distortion of an optical system according to the first embodiment of the present invention at a wide angle for light with wavelengths of 435 nm, 486 nm, 546 nm, 587 nm, and 656 nm.

[0170] Figure 4b The measurement diagrams of longitudinal spherical aberration, astigmatism curves, and distortion of the optical system according to the first embodiment of the present invention in intermediate mode for light with wavelengths of 435 nm, 486 nm, 546 nm, 587 nm, and 656 nm are shown.

[0171] Figure 4c This is a measurement diagram of longitudinal spherical aberration, astigmatism curve, and distortion of an optical system according to a first embodiment of the present invention at long focal length for light with wavelengths of 435 nm, 486 nm, 546 nm, 587 nm, and 656 nm.

[0172] Reference Figures 4a to 4c It can be seen that, regardless of the wavelength, the longitudinal spherical aberration ranges from -0.05 mm to 0.025 mm from the center to the edge of the image sensor. Specifically, it can be seen that the longitudinal spherical aberration is in the range of approximately -0.02 mm to 0.02 mm at wide-angle and in the range of -0.025 mm to 0.025 mm at intermediate mode. It can also be seen that the longitudinal spherical aberration is in the range of -0.05 mm to 0.025 mm at telephoto.

[0173] Reference Figures 4a to 4c It can be seen that, regardless of the wavelength, the astigmatism curve ranges from -0.025mm to 0.01mm from the center to the edge of the image sensor. Specifically, it can be seen that the astigmatism curve is in the range of approximately -0.005mm to 0.01mm at wide-angle and in the range of -0.02mm to 0.01mm at intermediate mode. It can also be seen that the astigmatism curve is in the range of approximately -0.025mm to 0.01mm at telephoto.

[0174] Reference Figures 4a to 4c It can be seen that, regardless of the wavelength, the distortion ranges from -0.25% to 1% from the center to the edge of the image sensor. Specifically, it can be seen that the distortion is in the range of approximately -0.25% to 0.2% at wide-angle and in the range of 0% to 0.2% at intermediate mode. It can be seen that the distortion is in the range of approximately 0% to 1% at telephoto.

[0175] Next, we will refer to Figure 5a and 5b The simulation results of the modulation transfer function (MTF) of a zoom optical system according to an embodiment of the present invention are described. MTF refers to one of the methods used to measure the performance of an optical system.

[0176] Figure 5a This is the MTF diagram of the optical system according to the embodiment at a wide angle. Figure 5b This is the MTF diagram of the optical system according to the embodiment at long focal length.

[0177] Reference Figure 5a and Figure 5b As can be seen, the zoom optical system according to the embodiment of the present invention has a value close to the diffraction limit (which is the limit value) near the defocus position (0mm) at both wide-angle and telephoto angles.

[0178] Figure 6a This is a cross-sectional view of the zoom optical system according to the second embodiment of the present invention at a wide angle. Figure 6b This is a cross-sectional view of the zoom optical system according to the second embodiment of the present invention in intermediate mode. Figure 6c This is a cross-sectional view of the zoom optical system according to the second embodiment of the present invention at a telephoto focal length.

[0179] Tables 6 and 7 below show the optical characteristics of the lenses included in the zoom optical system according to the second embodiment of the present invention, and Tables 8 and 9 show the conic constants and aspherical coefficients of the lenses included in the zoom optical system according to the second embodiment of the present invention.

[0180] [Table 6]

[0181]

[0182] [Table 7]

[0183]

[0184] [Table 8]

[0185]

[0186] [Table 9]

[0187] 112 -8.09E-05 1.39E-05 -1.55E-06 1.01E-07 -2.89E-09 114 -1.42E-04 1.60E-05 -4.10E-07 -9.26E-08 7.29E-09 122 3.77E-04 -1.21E-04 2.23E-05 -2.20E-06 8.91E-08 124 5.60E-04 -1.51E-04 2.23E-05 -1.77E-06 6.00E-08 132 -9.06E-04 1.27E-04 -1.49E-05 1.29E-06 -5.36E-08 134 3.74E-05 -6.53E-05 1.40E-05 -1.33E-06 4.83E-08 212 2.91E-04 -7.13E-05 1.06E-05 -8.82E-07 3.15E-08 214 -5.32E-04 9.80E-05 -1.05E-05 5.57E-07 -8.13E-09 222 -6.40E-04 1.35E-04 -1.74E-05 1.22E-06 -3.42E-08 224 3.96E-03 -1.39E-03 2.97E-04 -3.53E-05 1.80E-06 312 1.49E-03 -4.01E-04 6.64E-05 -6.18E-06 2.48E-07 314 -3.10E-03 8.51E-04 -1.39E-04 1.23E-05 -4.59E-07 322 -6.48E-03 1.74E-03 -2.78E-04 2.43E-05 -8.88E-07 324 -9.14E-04 1.66E-04 -1.90E-05 1.20E-06 -3.12E-08

[0188] Reference Figures 6a to 6c As per Tables 6 to 9, the zoom optical system includes a first lens group 100, a second lens group 200, and a third lens group 300 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. In Table 6, thickness [mm] represents the distance from each lens surface to the next lens surface.

[0189] For example, the thickness described for the object-side surface 112 of the first lens 110 represents the distance from the object-side surface 112 of the first lens 110 to the image-side surface 114 of the first lens 110. Specifically, the thickness described for 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 of the first lens 110.

[0190] The thickness described for 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 described for 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.

[0191] The thickness described for 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 described for the image-side surface 134 of the third lens 130 represents 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.

[0192] In this case, the second lens group 200 moves during the zoom from wide-angle to telephoto, thus the thickness recorded on the image-side surface 134 of the third lens 130 can change. The thickness recorded on the image-side surface 134 of the third lens 130 can have a value between the longest and shortest distances. Referring to Table 6, the thickness recorded on the image-side surface 134 of the third lens 130 can have a longest distance of 2.39383 at wide-angle. The thickness recorded on the image-side surface 134 of the third lens 130 can have a value between the shortest and longest distances in intermediate mode. The thickness recorded on the image-side surface 134 of the third lens 130 can have a shortest distance of 0.4026 at telephoto. The thicknesses recorded on the image-side surfaces of the fifth lens 220 and the seventh lens 320 are also equal.

[0193] Referring to Table 7, each surface of the first lens 110 to the seventh lens 320 can be implemented as convex or concave.

[0194] The first lens 110 can be a lens whose object-side surface 112 convexes towards the object side. The first lens 110 can also be a lens whose image-side surface 114 is recessed towards the object side. The second lens 120 can be a lens whose object-side surface 122 is recessed towards the object side. The second lens 120 can also be a lens whose image-side surface 124 is recessed towards the object side. The third lens 130 can be a lens whose object-side surface 132 convexes towards the object side. The third lens 130 can also be a lens whose image-side surface 134 convexes towards the object side.

[0195] The fourth lens 210 can be a lens whose object-side surface 212 convexes towards the object side. The fourth lens 210 can also be a lens whose image-side surface 214 is recessed towards the object side. The fifth lens 220 can be a lens whose object-side surface 222 is recessed towards the object side. The fifth lens 220 can also be a lens whose image-side surface 224 convexes towards the object side.

[0196] On the other hand, when the distance between the first lens group 100 and the second lens group 200 is the minimum distance (i.e. at telephoto), the center of curvature of the object-side surface 212 of the fourth lens 210 can be located closer to the image side than the two ends of the image-side surface 134 of the third lens 130.

[0197] The sixth lens 310 can be a lens with its object-side surface 312 recessed towards the object side. The sixth lens 310 can also be a lens with its image-side surface 314 recessed towards the object side. The seventh lens 320 can be a lens with its object-side surface 322 protruding towards the object side. The seventh lens 320 can also be a lens with its image-side surface 324 protruding towards the object side.

[0198] Reference Figure 6a 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 image sensor 10 is d3a, the zoom optical system can have a wide angle (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 image sensor 10 is d3a, the zoom optical system can have a wide angle.

[0199] exist Figure 6b In this zoom optical system, an intermediate mode is possible 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 image sensor 10 is d3b. That is, an intermediate mode is possible 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 image sensor 10 is d3b.

[0200] exist Figure 6c 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 image sensor 10 is d3c, the zoom optical system can have a telephoto lens (e.g., 5x 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 image sensor 10 is d3c, the zoom optical system can have a telephoto lens.

[0201] As the magnification changes from wide-angle to telephoto, the distance between adjacent lens groups can be altered.

[0202] The distance between the first lens group 100 and the second lens group 200 can be changed from d1a to d1b and then to d1c. Referring to Table 6, at wide-angle, the distance d1a between the first lens group 100 and the second lens group 200 is 2.39383 mm. At telephoto, the distance d1c between the first lens group 100 and the second lens group 200 is 0.4026 mm. As described above, during the process of changing the magnification from wide-angle to telephoto via intermediate mode, the distance between the first lens group 100 and the second lens group 200 can change from 2.39383 mm to 0.4026 mm. That is, during the process of changing the magnification from wide-angle to telephoto, the distance between the first lens group 100 and the second lens group 200 can gradually decrease (d1a > d1b > d1c). During the process of changing the magnification from wide-angle to telephoto, the amount of increase in the distance between the first lens group 100 and the second lens group 200 can gradually decrease.

[0203] The distance between the second lens group 200 and the third lens group 300 can be changed from d2a to d2c via d2b. Referring to Table 6, at wide-angle, the distance d2a between the second lens group 200 and the third lens group 300 is 1.6146mm. At telephoto, the distance d1c between the second lens group 200 and the third lens group 300 is 1.0112mm. As described above, during the process of changing the magnification from wide-angle to telephoto via intermediate mode, the distance between the second lens group 200 and the third lens group 300 can be changed from 1.6146mm to 1.0112mm. That is, during the process of changing the magnification from wide-angle to telephoto, the distance between the second lens group 200 and the third lens group 300 can decrease (d2a > d2b > d2c). In this case, the amount of increase in the distance between the second lens group 200 and the third lens group 300 during the process of changing the magnification from wide-angle to telephoto can gradually decrease.

[0204] The distance between the third lens group 300 and the image sensor 10 can be changed from d3a to d3b and then to d3c. Referring to Table 6, at wide-angle, the distance d3a between the third lens group 300 and the image sensor 10 is 1.59972 mm. At telephoto, the distance d3c between the third lens group 300 and the image sensor 10 is 4.19435 mm. As described above, the distance between the third lens group 300 and the image sensor 10 can change from 1.59972 mm to 4.19435 mm as the magnification changes from wide-angle to telephoto via intermediate mode. During the change from wide-angle to telephoto, the distance between the third lens group 300 and the image sensor 10 gradually increases (d3a < d3b < d3c). However, the amount of increase in the distance between the third lens group 300 and the image sensor 10 can gradually decrease during the change from wide-angle to telephoto.

[0205] The second lens group 200 and the third lens group 300 can have different moving speeds.

[0206] As the second lens group 200 and the third lens group 300 move, the magnification of the zoom optical system can be continuously adjusted from 3x to 5x.

[0207] Next, we will refer to Figures 7a to 7c The simulation results of longitudinal spherical aberration, astigmatism curve, and distortion of a zoom optical system according to a first embodiment of the present invention are described. Longitudinal spherical aberration refers to the longitudinal spherical aberration per wavelength, astigmatism curve refers to the aberration characteristics of the tangential plane and sagittal plane of the image surface height, and distortion refers to the degree of distortion of the image surface height.

[0208] Figure 7aThis is a measurement diagram of longitudinal spherical aberration, astigmatism curve, and distortion of light with wavelengths of 435 nm, 486 nm, 546 nm, 587 nm, and 656 nm in an optical system according to a second embodiment of the present invention, at a wide angle.

[0209] Figure 7b This is a measurement diagram of longitudinal spherical aberration, astigmatism curve, and distortion of light with wavelengths of 435 nm, 486 nm, 546 nm, 587 nm, and 656 nm in an optical system according to a second embodiment of the present invention, in intermediate mode.

[0210] Figure 7c This is a measurement diagram of longitudinal spherical aberration, astigmatism curve, and distortion of light with wavelengths of 435nm, 486nm, 546nm, 587nm, and 656nm in an optical system according to a second embodiment of the present invention, at long focal length.

[0211] Reference Figures 7a to 7c It can be seen that, regardless of the wavelength, the longitudinal spherical aberration ranges from -0.013 mm to 0.025 mm from the center to the edge of the image sensor. Specifically, it can be seen that the longitudinal spherical aberration is in the range of approximately -0.01 mm to 0.025 mm at wide-angle and in the range of -0.013 mm to 0.02 mm at intermediate mode. It can also be seen that at telephoto, the longitudinal spherical aberration is in the range of -0.013 mm to 0.02 mm.

[0212] Reference Figures 7a to 7c It can be seen that, regardless of the wavelength, the astigmatism curve ranges from -0.03mm to 0.04mm from the center to the edge of the image sensor. Specifically, it can be seen that the astigmatism curve is in the range of approximately -0.025mm to 0.02mm at wide-angle and in the range of -0.03mm to 0.025mm at intermediate mode. It can be seen that at telephoto, the astigmatism curve is in the range of approximately -0.01mm to 0.04mm.

[0213] Reference Figures 7a to 7c It can be seen that, regardless of wavelength, the distortion ranges from -0.4% to 0.8% from the center to the edge of the image sensor. Specifically, it can be seen that the distortion is in the range of approximately -0.4% to 0.2% at wide-angle and in the range of 0% to 0.3% at intermediate mode. It can be seen that at telephoto, the distortion is in the range of approximately 0% to 0.8%.

[0214] Next, we will refer to Figure 8a and Figure 8b The MTF simulation results of a zoom optical system according to an embodiment of the present invention are described. MTF refers to one of the methods used to measure the performance of an optical system.

[0215] Figure 8a This is the MTF diagram of the optical system according to the embodiment at a wide angle. Figure 8b This is a diffraction MTF diagram of the optical system under long focal length according to the embodiment.

[0216] Reference Figure 8a and Figure 8b As can be seen, the zoom optical system according to the embodiment of the present invention has a value close to the diffraction limit (which is the limit value) near the defocus position (0mm) at both wide-angle and telephoto angles.

[0217] Figure 9a This is a cross-sectional view of the zoom optical system according to the third embodiment of the present invention at a wide angle. Figure 9b This is a cross-sectional view of the zoom optical system according to the third embodiment of the present invention in intermediate mode. Figure 9c This is a cross-sectional view of the zoom optical system according to the third embodiment of the present invention at a telephoto focal length.

[0218] Tables 10 and 11 below show the optical characteristics of the lenses included in the zoom optical system according to the third embodiment of the present invention, and Tables 12 and 13 show the conic constants and aspherical coefficients of the lenses included in the zoom optical system according to the third embodiment of the present invention.

[0219] [Table 10]

[0220]

[0221] [Table 11]

[0222]

[0223] [Table 12]

[0224]

[0225] [Table 13]

[0226] 112 1.15E-05 -9.42E-07 -1.53E-07 3.79E-08 -2.22E-09 114 -7.28E-06 6.44E-07 -1.21E-07 2.99E-08 -2.77E-09 122 -1.61E-06 -1.13E-06 1.49E-07 2.52E-08 -1.18E-09 124 8.27E-07 -1.72E-06 -1.35E-07 1.04E-07 -7.07E-09 132 1.88E-03 -4.06E-04 5.35E-05 -3.88E-06 1.19E-07 134 1.50E-03 -3.40E-04 4.90E-05 -4.07E-06 1.49E-07 212 -1.91E-04 4.09E-05 -5.00E-06 2.95E-07 -4.20E-09 214 5.54E-04 -2.22E-04 4.90E-05 -5.81E-06 2.93E-07 222 -3.84E-05 -1.07E-05 3.74E-06 -4.40E-07 2.05E-08 224 -6.51E-04 2.38E-04 -5.30E-05 6.55E-06 -3.45E-07 312 1.93E-05 -8.20E-06 1.06E-06 3.90E-08 -9.59E-09 314 7.54E-05 -1.23E-06 -2.19E-06 -9.06E-08 3.29E-08 322 1.63E-03 -4.27E-04 4.63E-05 -3.62E-07 -2.42E-07 324 -7.19E-04 8.68E-05 -6.21E-06 1.77E-07 3.03E-09

[0227] Reference Figure 9a According to Tables 9C and 10 to 13, the zoom optical system includes a first lens group 100, a second lens group 200, and a third lens group 300 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. In Table 10, thickness [mm] represents the distance from each lens surface to the next lens surface.

[0228] For example, the thickness described for the object-side surface 112 of the first lens 110 represents the distance from the object-side surface 112 of the first lens 110 to the image-side surface 114 of the first lens 110. Specifically, the thickness described for 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 of the first lens 110.

[0229] The thickness described for 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 described for 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.

[0230] The thickness described for 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 described for the image-side surface 134 of the third lens 130 represents 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.

[0231] In this configuration, the second lens group 200 moves during the zoom process from wide-angle to focal length, thus altering the thickness recorded on the image-side surface 134 of the third lens 130. The thickness recorded on the image-side surface 134 of the third lens 130 can have a value between the longest and shortest distances. Referring to Table 10, at wide-angle, the thickness recorded on the image-side surface 134 of the third lens 130 can have a longest distance of 2.29633. In intermediate mode, the thickness recorded on the image-side surface 134 of the third lens 130 can have a value between the shortest and longest distances. At telephoto, the thickness recorded on the image-side surface 134 of the third lens 130 can have a shortest distance of 0.4. The thicknesses recorded on the image-side surfaces 224 of the fifth lens 220 and the seventh lens 320 are also equal.

[0232] Referring to Table 11, each surface of the first lens 110 to the seventh lens 320 can be made convex or concave.

[0233] The first lens 110 can be a lens whose object-side surface 112 bulges towards the object side. The first lens 110 can also be a lens whose image-side surface 114 bulges towards the object side. The second lens 120 can be a lens whose object-side surface 122 bulges towards the object side. The second lens 120 can also be a lens whose image-side surface 124 bulges towards the object side. The third lens 130 can be a lens whose object-side surface 132 bulges towards the object side. The third lens 130 can also be a lens whose image-side surface 134 bulges towards the object side.

[0234] The fourth lens 210 can be a lens whose object-side surface 212 bulges towards the object side. The fourth lens 210 can also be a lens whose image-side surface 214 is recessed towards the object side. The fifth lens 220 can be a lens whose object-side surface 222 is recessed towards the object side. The fifth lens 220 can also be a lens whose image-side surface 224 is recessed towards the object side.

[0235] On the other hand, when the distance between the first lens group 100 and the second lens group 200 is the minimum distance (i.e. at telephoto), the center of curvature of the object-side surface 212 of the fourth lens 210 can be located closer to the image side than the two ends of the image-side surface 134 of the third lens 130.

[0236] The sixth lens 310 can be a lens with its object-side surface 312 recessed towards the object side. The sixth lens 310 can also be a lens with its image-side surface 314 recessed towards the object side. The seventh lens 320 can be a lens with its object-side surface 322 protruding towards the object side. The seventh lens 320 can also be a lens with its image-side surface 324 protruding towards the object side.

[0237] Reference Figure 9a 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 image sensor 10 is d3a, the zoom optical system can have a wide angle (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 image sensor 10 is d3a, the zoom optical system can have a wide angle.

[0238] exist Figure 9bIn this zoom optical system, an intermediate mode is possible 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 image sensor 10 is d3b. That is, an intermediate mode is possible 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 image sensor 10 is d3b.

[0239] exist Figure 9c 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 image sensor 10 is d3c, the zoom optical system can have a telephoto lens (e.g., 5x 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 image sensor 10 is d3c, the zoom optical system can have a telephoto lens.

[0240] As the magnification changes from wide-angle to telephoto, the distance between adjacent lens groups can be altered.

[0241] The distance between the first lens group 100 and the second lens group 200 can be changed from d1a to d1c via d1b. Referring to Table 10, at wide-angle, the distance d1a between the first lens group 100 and the second lens group 200 is 2.29633mm. At telephoto, the distance d1c between the first lens group 100 and the second lens group 200 is 0.4mm. As described above, during the process of changing the magnification from wide-angle to telephoto via intermediate mode, the distance between the first lens group 100 and the second lens group 200 can be changed from 2.29633mm to 0.4mm. That is, during the process of changing the magnification from wide-angle to telephoto, the distance between the first lens group 100 and the second lens group 200 can gradually decrease (d1a > d1b > d1c). During the process of changing the magnification from wide-angle to telephoto, the amount of increase in the distance between the first lens group 100 and the second lens group 200 can gradually decrease.

[0242] The distance between the second lens group 200 and the third lens group 300 can be changed from d2a to d2c via d2b. Referring to Table 10, at wide angle, the distance d2a between the second lens group 200 and the third lens group 300 is 1.94114 mm. At telephoto, the distance d1c between the second lens group 200 and the third lens group 300 is 1.7963 mm. As described above, during the process of changing the magnification from wide angle to telephoto via intermediate mode, the distance between the second lens group 200 and the third lens group 300 can be changed from 1.94114 mm to 1.7963 mm. That is, during the process of changing the magnification from wide angle to telephoto, the distance between the second lens group 200 and the third lens group 300 can decrease (d2a > d2b > d2c). In this case, the amount of increase in the distance between the second lens group 200 and the third lens group 300 during the process of changing the magnification from wide angle to telephoto can gradually decrease.

[0243] The distance between the third lens group 300 and the image sensor 10 can be changed from d3a to d3b and then to d3c. Referring to Table 10, at wide-angle, the distance d3a between the third lens group 300 and the image sensor 10 is 2.35546 mm. At telephoto, the distance d3c between the third lens group 300 and the image sensor 10 is 4.639663 mm. As described above, during the process of changing the magnification from wide-angle to telephoto via intermediate mode, the distance between the third lens group 300 and the image sensor 10 can change from 2.35546 mm to 4.639663 mm. During the process of changing the magnification from wide-angle to telephoto, the distance between the third lens group 300 and the image sensor 10 gradually increases (d3a < d3b < d3c). However, during the process of changing the magnification from wide-angle to telephoto, the amount of increase in the distance between the third lens group 300 and the image sensor 10 can gradually decrease.

[0244] The second lens group 200 and the third lens group 300 can have different moving speeds.

[0245] As the second lens group 200 and the third lens group 300 move, the magnification of the zoom optical system can be continuously adjusted from 3x to 5x.

[0246] Next, we will refer to Figures 10a to 10c The simulation results of longitudinal spherical aberration, astigmatism curve, and distortion of a zoom optical system according to a third embodiment of the present invention are described. Longitudinal spherical aberration refers to the longitudinal spherical aberration per wavelength, astigmatism curve refers to the aberration characteristics of the tangential plane and sagittal plane of the image surface height, and distortion refers to the degree of distortion of the image surface height.

[0247] Figure 10aThis is a measurement diagram of longitudinal spherical aberration, astigmatism curve, and distortion of light with wavelengths of 435 nm, 486 nm, 546 nm, 587 nm, and 656 nm in an optical system according to a third embodiment of the present invention, at a wide angle.

[0248] Figure 10b This is a measurement diagram of longitudinal spherical aberration, astigmatism curve, and distortion of light with wavelengths of 435 nm, 486 nm, 546 nm, 587 nm, and 656 nm in an optical system according to a third embodiment of the present invention, in intermediate mode.

[0249] Figure 10c This is a measurement diagram of longitudinal spherical aberration, scattering curve, and distortion of light with wavelengths of 435nm, 486nm, 546nm, 587nm, and 656nm in an optical system under telephoto focal length, according to the third embodiment of the present invention.

[0250] Reference Figures 10a to 10c It can be seen that, regardless of the wavelength, the longitudinal spherical aberration is within 0.055 mm from the center to the edge of the image sensor. Specifically, it can be seen that the longitudinal spherical aberration is within approximately 0.025 mm at wide-angle and within 0.040 mm in intermediate mode. It can also be seen that at telephoto, the longitudinal spherical aberration is within 0.055 mm.

[0251] Reference Figures 10a to 10c It can be seen that, regardless of the wavelength, the astigmatism curve ranges from -0.035mm to 0.050mm from the center to the edge of the image sensor. Specifically, it can be seen that at wide-angle, although the astigmatism curve extends beyond the range at the edges of the image sensor, it remains within the range of approximately -0.025mm to 0.020mm, and in intermediate mode, it is within the range of -0.025mm to 0.050mm. It can also be seen that at telephoto, the astigmatism curve remains within the range of approximately -0.035mm to 0.020mm.

[0252] Reference Figures 10a to 10c It can be seen that, regardless of the wavelength, the distortion ranges from -0.4% to 1% from the center to the edge of the image sensor. Specifically, it can be seen that the distortion is in the range of approximately -0.4% to 0.5% at wide-angle and in the range of 0% to 0.75% at intermediate mode. It can be seen that the distortion is in the range of approximately 0% to 1% at telephoto.

[0253] Next, we will refer to Figure 11a and Figure 11b The MTF simulation results of a zoom optical system according to an embodiment of the present invention are described. MTF refers to one of the methods used to measure the performance of an optical system.

[0254] Figure 11a This is the MTF diagram of the optical system according to the embodiment at a wide angle. Figure 11b This is the MTF diagram of the optical system according to the embodiment at long focal length.

[0255] Reference Figure 11a and Figure 11b As can be seen, the zoom optical system according to the embodiment of the present invention has a value close to the diffraction limit (which is the limit value) near the defocus position (0mm) at both wide-angle and telephoto angles.

[0256] Figure 12 This is a view illustrating a zoom optical system according to an embodiment of the present invention.

[0257] Figure 12 The zoom optical system shown may further include a reference. Figure 1 The described dummy lens in a zoom optical system.

[0258] Reference Figure 12 According to an embodiment of the present invention, a zoom optical system may include a first lens group, a second lens group, a third lens group, a filter, and a sensor arranged sequentially from the object side, and a dummy lens may be further included between the third lens group and the filter.

[0259] The width of the dummy lens can be greater than the width of the first lens group. The effective diameter of the dummy lens can be greater than the effective diameter of the first lens group. The effective diameter of the dummy lens can be greater than the effective diameter of each lens included in the first lens group.

[0260] A dummy lens can be fixed. A dummy lens can be fixed relative to the image side.

[0261] A dummy lens can be referred to as the fourth lens group. A dummy lens may include, but is not limited to, one lens, and may include multiple lenses.

[0262] A dummy lens can be used to block foreign objects that may be introduced when the second and third lens groups move. A dummy lens can prevent foreign objects from entering the sensor.

[0263] Figure 13 This is a view showing a portion of a portable terminal that applies a camera module according to an embodiment of the present invention.

[0264] On the other hand, the zoom optical system according to an embodiment 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, and the zoom optical system according to an embodiment of the present invention may include the first lens group 100, the second lens group 200, and the third lens group 300 described above. A portable terminal equipped with a camera module including a zoom optical system according to an embodiment of the present invention can be a smartphone, a tablet PC, a laptop computer, a personal digital assistant (PDA), etc. The optical system according to an embodiment of the present invention can be applied to a camera module.

[0265] Reference Figure 13 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.

[0266] The zoom optical system 1000 according to an embodiment of the present invention may include the first lens group 100, the second lens group 200, and the third lens group 300 described above. Due to the thickness limitation of the portable terminal, the first lens group 100, the second lens group, and the third lens group 300 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, when the lens surfaces of the lenses included in the zoom optical system are disposed in the thickness direction of the portable terminal, the diameter of the lenses included in the zoom optical system can be reduced, thereby reducing the thickness of the portable terminal. Therefore, a zoom optical system in which the magnification is continuously adjusted by moving the lens can also be installed in the portable terminal.

[0267] A 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, PDA, etc.

[0268] The zoom optical system according to an embodiment of the present invention includes a first lens group, a second lens group, and a third lens group arranged sequentially from the object side to the image side, wherein the second lens group and the third lens group are movable, and the effective focal length (EFL) at wide angle is defined by the following formula.

[0269]

[0270] Among them, EFL wideH refers to the effective focal length of a zoom optical system at wide angles. imageD It refers to half the diagonal length of the pixel area of ​​the image sensor.

[0271] The first lens group may include three or fewer lenses, the second lens group may include two or fewer lenses, and the third lens group may include two or fewer lenses.

[0272] The effective focal length at long focal length can be defined by the following formula.

[0273]

[0274] Among them, EFL tele H refers to the effective focal length of a zoom optical system at long focal lengths. imageD It refers to half the diagonal length of the pixel area of ​​the image sensor.

[0275] During the zoom process from wide-angle to telephoto, the movement stroke of the second lens group can be defined by the following formula.

[0276]

[0277] Where TTL refers to the distance from the surface of the image sensor to the first surface of the zoom optical system, and STROKE2 refers to the stroke of the second lens group.

[0278] The movement stroke of the third lens group during the zoom process from wide-angle to telephoto can be defined by the following formula.

[0279]

[0280] Here, TTL refers to the distance from the surface of the image sensor to the first surface of the zoom optical system, and STROKE3 refers to the stroke of the third lens group.

[0281] Each of the first lens group, the second lens group, and the third lens group may include a plastic lens.

[0282] The maximum diameter of the multiple lenses included in the first lens group, as well as the maximum diameter of the multiple lenses included in the second and third lens groups, can be defined by the following formula.

[0283]

[0284] Among them, APER fix It can refer to the maximum diameter of the lenses included in the first lens group of the fixed group, APER. mov It can refer to the maximum diameter of the lenses included in the second and third lens groups, which are part of the moving group.

[0285] CRA can be greater than -20° and less than -10°.

[0286] It may further include a right-angle prism positioned in front of the first lens group.

[0287] It may further include a dummy lens positioned behind the third lens group.

[0288] The effective diameter of the virtual lens can be greater than the effective diameter of the first lens group.

[0289] The zoom optical system according to an embodiment of the present invention includes a first lens group, a second lens group, and a third lens group arranged sequentially from the object side to the image side, wherein the second lens group and the third lens group are movable, and the effective focal length at telephoto is defined by the following formula.

[0290]

[0291] Among them, EFL tele H refers to the effective focal length of a zoom optical system at long focal lengths. imageD It refers to half the diagonal length of the pixel area of ​​the image sensor.

[0292] The zoom optical system according to an embodiment of the present invention includes a first lens group, a second lens group, and a third lens group arranged sequentially from the object side to the image side, wherein the first lens group is fixed, the second lens group and the third lens group are movable, the second lens group performs the zoom function, the third lens group performs the focusing function, the movement stroke of the second lens group is less than 2 mm, and the zoom optical system corresponding to the movement stroke (less than 2 mm) of the second lens group is defined by the following formula when the distance from the surface of the image sensor to the first surface of the zoom optical system is less than 17 mm.

[0293]

[0294] Among them, EFL tele EFL refers to the effective focal length at long focal lengths. wide This refers to the effective focal length in wide-angle mode.

[0295] According to an embodiment of the present invention, a zoom optical system includes a first lens group, a second lens group, and a third lens group arranged sequentially from the object side to the image side, wherein the first lens group is fixed, the second lens group and the third lens group are movable, the second lens group performs a zoom function, the third lens group performs a focusing function, the focal length at telephoto is greater than 14mm, and the F-number at telephoto is less than 3.

[0296] According to an embodiment of the present invention, a zoom optical system includes a first lens group, a second lens group, and a third lens group arranged sequentially from the object side to the image side, wherein the first lens group is fixed, the second lens group and the third lens group are movable, the second lens group performs a zoom function, the third lens group performs a focusing function, the focal length at wide angle is less than 10mm, and the F number at wide angle is less than 2.3.

[0297] The zoom optical system according to an embodiment of the present invention includes a first lens group, a second lens group, and a third lens group arranged sequentially from the object side to the image side, wherein the first lens group is fixed, the second lens group and the third lens group are movable, the second lens group performs a zoom function, the third lens group performs a focusing function, and the diagonal length of the pixel area of ​​the image sensor disposed behind the third lens group is greater than 6 mm.

[0298] Although embodiments have been described primarily, they are merely examples and do not limit the invention. Those skilled in the art will understand that various modifications and applications can be made without departing from the essential characteristics of the embodiments. For example, the 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, and a third lens group arranged sequentially from the object side to the image side. in, The zoom optical system does not include any other lens groups besides the first lens group, the second lens group, and the third lens group. The first lens group consists of a first lens, a second lens, and a third lens. The second lens group consists of a fourth lens and a fifth lens. The third lens group consists of a sixth lens and a seventh lens. The first lens, the second lens, the fourth lens, and the sixth lens have positive optical power, while the third lens, the fifth lens, and the seventh lens have negative optical power. The second and third lens groups are movable, and the effective focal length (EFL) at wide angles is defined by the following formula. Among them, EFL wide H refers to the effective focal length of the zoom optical system at a wide angle. imageD It refers to half the diagonal length of the pixel region of the image sensor, and With the distance from the surface of the image sensor to the first surface of the zoom optical system less than 17 mm and the movement stroke of the second lens group less than 2 mm, the effective focal length (EFL) at wide-angle and telephoto angles is defined by the following formula: Among them, EFL wide EFL refers to the effective focal length of the zoom optical system at wide angles. tele This refers to the effective focal length of the zoom optical system at long focal lengths.

2. The zoom optical system according to claim 1, wherein, The effective focal length at long focal lengths is defined by the following formula. Among them, EFL tele H refers to the effective focal length of a zoom optical system at long focal lengths. imageD It refers to half the diagonal length of the pixel area of ​​the image sensor.

3. The zoom optical system according to claim 1, wherein, The movement stroke of the second lens group during zooming from wide-angle to telephoto is defined by the following formula: Where TTL refers to the distance from the surface of the image sensor to the first surface of the zoom optical system, and STROKE2 refers to the stroke of the second lens group.

4. The zoom optical system according to claim 1, wherein, The movement stroke of the third lens group during zooming from wide-angle to telephoto is defined by the following formula: Here, TTL refers to the distance from the surface of the image sensor to the first surface of the zoom optical system, and STROKE3 refers to the stroke of the third lens group.

5. The zoom optical system according to claim 1, wherein, The first lens group, the second lens group, and the third lens group all include plastic lenses.

6. 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 maximum diameter of the plurality of lenses included in the second lens group and the third lens group are defined by the following formula: Among them, APER fix APER refers to the maximum diameter of the lenses included in the first lens group, which is a fixed group. mov This refers to the maximum diameter of the lenses included in the second and third lens groups, which are considered as a movable group.

7. The zoom optical system according to claim 1, wherein, The principal ray angle, i.e., CRA, is greater than -20° and less than -10°.

8. The zoom optical system according to claim 1 further includes a right-angle prism disposed in front of the first lens group.

9. The zoom optical system according to claim 1 further includes a dummy lens disposed behind the third lens group.

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

11. The zoom optical system according to claim 1, wherein, A filter and an image sensor are arranged sequentially behind the third lens group.

12. The zoom optical system according to claim 1, wherein, The first to the seventh lenses are D-cut lenses, in which a portion of the upper side and a portion of the lower side are cut.

13. The zoom optical system according to claim 1, wherein, In the seventh lens, the major axis length is greater than the minor axis length, and the minor axis length is less than the effective diameter.

14. The zoom optical system according to claim 1, wherein, As the second lens group and the third lens group move, the magnification of the zoom optical system continuously increases or decreases between 3x and 5x.

15. The zoom optical system according to claim 1, wherein, The apertures of the second lens group and the third lens group are smaller than the aperture of the first lens group.

16. The zoom optical system according to claim 1, wherein, The first lens, the third lens, the fourth lens, and the seventh lens have object-side surfaces that bulge toward the object side, while the second lens, the fifth lens, and the sixth lens have object-side surfaces that are recessed toward the object side.

17. The zoom optical system according to claim 1, wherein, The first lens, the second lens, and the third lens are arranged in sequence from the object side to the image side. The fourth lens and the fifth lens are arranged sequentially from the object side to the image side, and The sixth lens and the seventh lens are arranged in sequence from the object side to the image side.

18. The zoom optical system according to claim 9, wherein, The effective diameter of the dummy lens is greater than the effective diameter of the first lens group.

Images