Variable optical system and electronic device

Abstract

A variable optical system including a plurality of lenses and a lens group, and an electronic device having the variable optical system are provided. The variable optical system having a positive refractive power as a whole comprises: a first lens group (G1) having the positive refractive power and including at least four aspheric surfaces, the first lens group (G1) being movable within a movement range along an optical axis direction; a second lens group (G2) comprising at least four aspheric surfaces, the second lens group (G2) being movable and configured to be located on the optical axis (OA) or outside the optical path; and a third lens group (G3). The variable optical system switches between a first state and a second state. In the first state, the first lens group (G1) moves from a position close to an image side to a position close to an object side so as to focus from infinity to a near object, the second lens group (G2) is outside an optical path and is not used for image formation, and the third lens group (G3) is located on the optical axis (OA) and is close to the first lens group (G1). In the second state, the second lens group (G2) is located on the optical axis (OA) and inserted into a part of a space generated by the first lens group (G1) moving to the object side in the first state, and is used as a part of the variable optical system for image formation.

Description

Technical Field

[0001] The present invention relates to an optical system including a plurality of lenses and lens groups, and an electronic device having the optical system. Background Art

[0002] In recent years, electronic devices such as mobile terminal devices have become very popular, and it has become common for these electronic devices to integrate compact camera units. The compactness of such camera units is required to be high, especially in the thickness direction of the electronic device. In addition, in recent years, in order to adapt to the shooting of various subjects, camera units with multiple camera modules have become increasingly common, including wide-angle lenses for normal shooting, ultra-wide-angle lenses with a larger angle than wide-angle lenses, and telephoto lenses with a longer focal length than wide-angle lenses.

[0003] Increasing the number of camera modules can achieve a wider focal range, but this will result in a larger size and higher cost of the electronic device. Therefore, the optical system used in one camera module is preferably an optical system that integrates multiple optical functions, specifically, a variable focal range optical system that can change the focal range.

[0004] In addition, in order to obtain high image quality, it is desirable that the F number of the optical system is small. Specifically, it is desirable that the F number is 3.0 or less, preferably 2.0 or less.

[0005] In addition, for such an optical system, it is desirable that the minimum object distance is small so that the object can be photographed at a close distance. In addition, it is desirable that the absolute value of the optical magnification is large so that the object can be optically magnified at a short distance.

[0006] Patent document 1 discloses a curved optical system including a reflective element for bending the optical axis by about 90 degrees in order to reduce the size of an electronic device in the thickness direction. In the curved optical system, a reflective element such as a prism or a reflector is disposed near the incident side of the optical system to bend the optical axis by about 90 degrees in order to reduce the size of the electronic device in the thickness direction - especially in a telephoto lens, whose total optical length tends to be longer.

[0007] Patent Documents 2 and 3 disclose a zoom lens having a reflective optical system (a curved zoom lens). The zoom lens having a reflective optical system provides a plurality of focal length ranges in a single camera module while achieving compactness in thickness of the electronic device.

[0008] However, the curved zoom lenses disclosed in Patent Documents 2 and 3 are configured such that two or more lens groups move along the optical axis to change the focal length. Therefore, in such curved zoom lenses, the total length of the optical system becomes too long. Moreover, in such curved zoom lenses, since the movement of two or more lens groups causes a large change in aberration, it is difficult to reduce the F number while maintaining a compact size.

[0009] Furthermore, in such a curved zoom lens, it is difficult to keep the F value below 2.0 or 3.0 while maintaining a compact size, and it is also difficult to shorten the minimum object distance or increase the absolute value of the optical magnification.

[0010] Due to the above reasons, conventional curved zoom lenses cannot solve the problem to be solved by the present invention. In other words, conventional curved zoom lenses cannot provide a compact, high-performance optical system with multiple functions, especially a variable focal length range optical system.

[0011] Therefore, the optical system proposed by the present invention intends to provide a variable focal range optical system that can reduce the F number and shorten the minimum object distance while making the camera unit miniaturized in the thickness direction, which is difficult to achieve in conventional technologies.

[0012] Citation List

[0013] Patent Literature

[0014] Patent document 1: US2020 / 0233178 A1

[0015] Patent Document 2: US 7,995,284 B2

[0016] Patent Document 3: US2019 / 0324236 A1 Summary of the invention

[0017] According to one aspect of the present invention, the optical system as a whole has positive refractive power, and has a first lens group including at least four aspherical surfaces, a second lens group including at least four aspherical surfaces, and a third lens group, and switches a first optical state and a second optical state when the second lens group, or the second lens group and the third lens group are inserted and removed.

[0018] The optical system has positive refractive power as a whole, has a first lens group including at least four aspherical surfaces, and acts as an imaging optical system. The optical system has a second lens group and a third lens group including at least four aspherical surfaces, and changes the lens configuration by switching between the first optical state and the second optical state when the second lens group, or the second lens group and the third lens group are inserted and removed. The optical system can act as a lens on the more telephoto side, for example, by having a longer focal length in the second state than in the first state, thereby narrowing the angle of view. When switching between the first state and the second state, the second lens group, or the second lens group and the third lens group are moved in a direction perpendicular to the optical axis by insertion or removal, thereby minimizing the size increase in the total length direction when changing the optical characteristics, and making it possible to miniaturize the electronic device in the thickness direction.

[0019] In order to achieve the miniaturization and high performance to be achieved by the present invention, it is necessary to effectively correct aberrations with a small number of lenses. Therefore, the first lens group includes at least four aspherical surfaces to effectively correct axial aberrations, including spherical aberrations and off-axis aberrations, such as coma and field curvature.

[0020] The optical system switches between a state in which the second lens group is inserted into the optical path and a state in which the second lens group is removed from the optical path. That is, when the second lens group moves, the optical system switches between the first optical state and the second optical state. With the switching of the states, the optical system can change optical characteristics such as focal length. The second lens group includes at least four aspherical surfaces so as to effectively correct the occurrence and change of aberrations caused by the insertion of the second lens group into the optical path while reducing the number of constituent lenses of the second lens group.

[0021] The lens with an aspherical surface is made of a material such as glass or plastic, and has an aspherical shape formed on one or both surfaces of the lens. The use of a glass aspherical lens allows for more freedom in selecting the lens refractive index, Abbe number, and anomalous partial dispersion, and is particularly effective in correcting lateral chromatic aberration. By using a glass aspherical lens in the first lens group having the main imaging function, lateral chromatic aberration occurring in the first lens group can be effectively corrected, and the optical system thus has high performance. In addition, performance changes caused by inserting the second lens group can be reduced. In addition, by using a plastic aspherical lens, the weight and cost of each lens group can be reduced.

[0022] According to one aspect of the present invention, the optical system is a curved optical system having a reflective element that bends the optical axis by about 90 degrees on the optical path from the object to the image. The reflective element is composed of a prism, a reflector, etc., and by bending the optical axis that forms an image from the object by about 90 degrees, the size of the imaging device can be reduced in the thickness direction even if a telephoto lens with a relatively long focal length is used. In addition, by rotating the reflective element in a predetermined manner with the aid of a drive mechanism, image blur caused by camera shake or the like can be corrected.

[0023] According to one aspect of the present invention, in the optical system, when switching between the first optical state and the second optical state, the second lens group moves perpendicular to the optical axis and parallel to the longitudinal direction of the imaging element. The effective area of ​​the imaging element used in the present invention is a rectangle with an aspect ratio, for example, a ratio of a long side to a short side of 4:3 or 3:2, and the imaging element is arranged so that the short side direction thereof coincides with the thickness direction of the imaging device. Therefore, when the second lens group is removed from the optical path, it moves parallel to the longitudinal direction without affecting the thickness direction of the imaging device, so that the size of the imaging device can be reduced in the thickness direction.

[0024] According to the above configuration, the optical system of the present invention can be an optical system having variable optical characteristics such as focal length while achieving a short overall length and a compact size in the thickness direction of the imaging device.

[0025] According to one aspect of the present invention, in the optical system, when the first state and the second state are switched, the first lens group moves to a different position on the optical axis. By moving the first lens group to a different position on the optical axis, it is easier to obtain a space for inserting the second lens group into the optical path, and the size of the optical system can be reduced, especially in the overall length direction. In addition, even if the focus position is shifted or the aberration changes due to the insertion or removal of the second lens group, correction is facilitated.

[0026] According to one aspect of the present invention, in the optical system, when focusing from infinity to a short-distance object, focusing can be performed by moving the first lens group along the optical axis toward infinity. With such a configuration, focusing can be performed by the first lens group in the first state and the second state, the drive device can be shared and simplified, and it also helps to miniaturize the optical system.

[0027] According to one aspect of the present invention, in the optical system, in the first state, the first lens group moves from the image side to the object side to focus on a short-distance object from infinity, and when switched to the second state, the second lens group is inserted into a part of the space on the optical path generated by the movement of the first lens group toward the object side in the first state. With this configuration, a space in which the second lens group can be inserted into the optical path can be obtained, and the space in the optical axis direction of the optical system can be effectively utilized, thereby reducing the total length.

[0028] According to one aspect of the present invention, the optical system has at least a second lens group and a third lens group, and in the first state, the third lens group is on the optical path and the second lens group is on the optical path; in the second state, the third lens group is outside the optical path and the second lens group is on the optical path. By switching the lens group acting on the optical system imaging in the first state and the second state, the optical characteristics such as focal length can be changed more effectively. Specifically, the lens configuration of the second lens group and the third lens group and their insertion positions on the optical axis can be optimized for each state, and high optical performance can be obtained even when the optical characteristics such as focal length are greatly changed.

[0029] According to one aspect of the present invention, in the optical system, at least one lens constituting the first lens group is non-circular and has different effective lengths in the long side direction and the short side direction. If the optical system is a curved optical system in which the optical axis is bent by about 90 degrees, the long side direction and the short side direction of the lens coincide with the long side direction and the short side direction of the imaging element, and the short side direction of the imaging element corresponds to the thickness direction of the imaging device as described above. In other words, in order to make the imaging device thinner, it is effective to reduce the size of the lens in the short side direction, and by using a non-circular lens having a shorter length in the short side direction, the size of the imaging device can be reduced in the thickness direction. Specifically, when trying to make the F number less than 3 or less than 3 or less than 2 or less, the length of the lens constituting the first lens group becomes a limitation of miniaturization in the thickness direction of the optical system. By using a non-circular lens in the first lens group, a small F number and a compact size in the thickness direction can be achieved.

[0030] According to one aspect of the present invention, the optical system has a second lens group and a third lens group in order from the first lens group toward the image side. By having the third lens group on the image side, off-axis aberrations such as lateral chromatic aberration, field curvature and distortion can be effectively corrected. If the optical system is a curved optical system that bends the optical axis by about 90 degrees, the lenses constituting the third lens group are preferably non-circular in order to reduce the size of the imaging device in the thickness direction. In addition, the lenses constituting the third lens group are preferably composed of about two to three lenses in order to achieve miniaturization in the total length direction of the optical system and achieve optical performance.

[0031] According to one aspect of the present invention, the optical system has a second reflecting element that bends the optical axis by about 90 degrees on the image side of the optical system. If the optical system is a curved optical system that bends the optical axis by about 90 degrees, by again bending the optical axis by about 90 degrees using the second reflecting element, even when the imaging element is moved parallel to the image plane for camera shake correction, an increase in size in the thickness direction of the imaging device can be avoided.

[0032] According to one aspect of the present invention, in the optical system, the first lens group is composed of at least three lenses and has at least four aspherical surfaces. By having at least four aspherical surfaces, the number of lenses and the lens configuration can be simplified, and aberration correction can be significantly performed. In addition, in order to achieve both miniaturization and optical performance in the total length direction of the optical system, the number of lenses constituting the first lens group is preferably three to four.

[0033] According to an aspect of the present invention, the optical system satisfies the following conditional expressions (1) to (3).

[0034] (1) 0.55<|FL1 / EFL1|<0.9

[0035] (2) 0.6<EFL1 / TTL<1.0

[0036] (3)0.2<|MAG|<1.0

[0037] Here, FL1 represents the focal length of the first lens group, EFL1 represents the focal length of the optical system in the first state, TTL represents the distance from the surface vertex of the first lens to the image plane on the optical axis when the optical system is focused on infinity in the first state, and MAG represents the optical magnification at the minimum object distance of the optical system.

[0038] Conditional expression (1) is used to appropriately set the focal length range of the first lens group. If the value is below the range of conditional expression (1), the refractive power of the first lens group becomes too strong, and aberrations such as spherical aberration and field curvature become noticeable, making it difficult to sufficiently correct. On the other hand, if the value exceeds the range of conditional expression (1), the refractive power becomes too weak, resulting in an increase in the total length of the optical system.

[0039] Conditional expression (2) is used to appropriately define the range of the ratio of the total focal length to the total length of the optical system in the first state. If the value is below the range of conditional expression (2), the total length becomes too short relative to the focal length, making it difficult to correct aberrations. On the other hand, if the value exceeds the range of conditional expression (2), the total length becomes too long relative to the focal length, making it unsuitable for miniaturization of the optical system.

[0040] Conditional expression (3) is used to define the range of optical magnification at the minimum object distance. The optical magnification is defined by the optical lateral magnification of the optical system in the minimum object distance state. If the value is lower than the range of conditional expression (3), the optical magnification provided by the present invention is not satisfied. In addition, the amount of movement of the focusing lens group is reduced, making it difficult to obtain space for inserting and removing the second lens group. On the other hand, if the value exceeds the range of conditional expression (3), the absolute value of the optical magnification becomes too large, making it difficult to correct aberrations, and the amount of movement of the focusing lens group becomes too large, making it difficult to reduce the total length. In addition, conditional expression (3) can be more preferably replaced by the following conditional expression (3'). If conditional expression (3') is satisfied, the above-mentioned effect can be obtained more effectively.

[0041] (3')0.3<|MAG|<0.7

[0042] According to an aspect of the present invention, the optical system satisfies the following conditional expressions (4) to (5).

[0043] (4) 0.7<|FL2 / EFL1|<2.3

[0044] (5)0.4<|FL3 / EFL2|<2.8

[0045] Here, FL2 represents the focal length of the second lens group, FL3 represents the focal length of the third lens group, and EFL2 represents the focal length of the optical system in the second state.

[0046] Conditional expression (4) is used to define the ratio of the focal length of the second lens group in the first state to the focal length of the optical system in the first state. If the value is below the range of conditional expression (4), the refractive power becomes too strong, making it difficult to correct aberrations. On the other hand, if the value exceeds the range of conditional expression (4), a sufficient effect cannot be obtained for changes in optical characteristics during insertion.

[0047] Conditional expression (5) is used to define the ratio of the focal length of the third lens group in the second state to the focal length of the optical system in the second state. If the value is below the range of conditional expression (5), the refractive power becomes too strong, making it difficult to correct aberrations. On the other hand, if the value is outside the range of conditional expression (5), a sufficient effect cannot be obtained for changes in optical characteristics during insertion.

[0048] According to an aspect of the present invention, the optical system satisfies the following conditional expression (6).

[0049] (6) 0.9<St / MgTTL<2.0

[0050] Here, St represents the maximum movement of the first lens group when focusing, and MgTTL represents the total lens length of the second lens group.

[0051] Conditional expression (6) is used to appropriately define the ratio of the maximum amount of movement of the first lens group during focusing to the total lens length of the second lens group. If the value is lower than the lower limit of conditional expression (6), a sufficient space cannot be obtained to insert the second lens group, or the total length of the optical system becomes large. On the other hand, if the value exceeds the upper limit of conditional expression (6), the amount of movement becomes too long, resulting in a long total length of the optical system, or the total lens length of the second lens group becomes too short, resulting in insufficient performance.

[0052] It should be understood that the contents described in the summary of the invention are not intended to limit the main or important features of the embodiments of the invention, or to limit the scope of the invention. Other features of the embodiments of the invention will be easily understood using the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] The above features, advantages and aspects of the embodiments of the present invention will become more apparent with reference to the accompanying drawings and the following detailed description.In the accompanying drawings, the same or similar reference numerals refer to the same or similar elements.

[0054] Figure 1-1 A schematic cross-sectional view of an optical system provided by a first example of the present invention when photographing at an infinite position in a first state is shown.

[0055] Figure 1-2 A schematic cross-sectional view of an optical system provided by a first example of the present invention when photographing at a minimum object distance in a first state is shown.

[0056] Figure 1-3 A schematic cross-sectional view of an optical system provided by a first example of the present invention when photographing at an infinite position in a second state is shown.

[0057] Figure 1-4 A schematic cross-sectional view of an optical system provided by a first example of the present invention is shown, the optical system illustrating the bending direction of a reflective element with respect to an optical axis.

[0058] Figure 1-5 Shown according to Figure 1-1 Spherical aberration, field curvature and distortion of the optical system.

[0059] Figure 1-6 Shown according to Figure 1-1 Diagram of lateral aberration of the optical system.

[0060] Figure 1-7 Shown according to Figure 1-2 Spherical aberration, field curvature and distortion of the optical system.

[0061] Figure 1-8 Shown according to Figure 1-2 Diagram of the lateral aberration of the optical system.

[0062] Figure 1-9 Shown according to Figure 1-3 Spherical aberration, field curvature and distortion of the optical system.

[0063] Figure 1-10 Shown according to Figure 1-3 Diagram of lateral aberration of the optical system.

[0064] Figure 2-1 A schematic cross-sectional view of an optical system provided by a second example of the present invention when photographing at an infinite position in a first state is shown.

[0065] Figure 2-2 A schematic cross-sectional view of an optical system provided by a second example of the present invention when photographing at a minimum object distance in a first state is shown.

[0066] Figure 2-3 A schematic cross-sectional view of an optical system provided by a second example of the present invention when photographing at an infinite position in a second state is shown.

[0067] Figure 2-4 A schematic cross-sectional view of an optical system provided by a second example of the present invention is shown, the optical system illustrating the bending direction of a reflective element with respect to an optical axis.

[0068] Figure 2-5 Shown according to Figure 2-1 Spherical aberration, field curvature and distortion of the optical system.

[0069] Figure 2-6 Shown according to Figure 2-1 Diagram of lateral aberration of the optical system.

[0070] Figure 2-7 Shown according to Figure 2-2 Spherical aberration, field curvature and distortion of the optical system.

[0071] Figure 2-8 Shown according to Figure 2-2 Diagram of lateral aberration of the optical system.

[0072] Figure 2-9 Shown according to Figure 2-3 Spherical aberration, field curvature and distortion of the optical system.

[0073] Figure 2-10 Shown according to Figure 2-3 Diagram of lateral aberration of the optical system.

[0074] Figure 3-1 A schematic cross-sectional view of an optical system provided by a third example of the present invention when photographing at an infinite position in a first state is shown.

[0075] Figure 3-2 A schematic cross-sectional view of an optical system provided by a third example of the present invention when photographing at a minimum object distance in a first state is shown.

[0076] Figure 3-3 A schematic cross-sectional view of an optical system provided by a third example of the present invention when photographing at an infinite position in a second state is shown.

[0077] Figure 3-4 A schematic cross-sectional view of an optical system provided by a third example of the present invention is shown, the optical system illustrating the bending direction of a reflective element with respect to an optical axis.

[0078] Figure 3-5 Shown according to Figure 3-1 Spherical aberration, field curvature and distortion of the optical system.

[0079] Figure 3-6 Shown according to Figure 3-1 Diagram of lateral aberration of the optical system.

[0080] Figure 3-7 Shown according to Figure 3-2 Spherical aberration, field curvature and distortion of the optical system.

[0081] Figure 3-8 Shown according to Figure 3-2 Diagram of lateral aberration of the optical system.

[0082] Figure 3-9 Shown according to Figure 3-3 Spherical aberration, field curvature and distortion of the optical system.

[0083] Figure 3-10 Shown according to Figure 3-3 Diagram of lateral aberration of the optical system.

[0084] Figure 4-1 A schematic cross-sectional view of an optical system provided by a fourth example of the present invention when photographing at an infinite position in a first state is shown.

[0085] Figure 4-2 A schematic cross-sectional view of an optical system provided by a fourth example of the present invention when photographing at a minimum object distance in a first state is shown.

[0086] Figure 4-3 A schematic cross-sectional view of an optical system provided by a fourth example of the present invention when photographing at an infinite position in a second state is shown.

[0087] Figure 4-4 A schematic cross-sectional view of an optical system provided by a fourth example of the present invention is shown, the optical system illustrating the bending direction of a reflective element with respect to an optical axis.

[0088] Figure 4-5 Shown according to Figure 4-1 Spherical aberration, field curvature and distortion of the optical system.

[0089] Figure 4-6 Shown according to Figure 4-1 Diagram of lateral aberration of the optical system.

[0090] Figure 4-7 Shown according to Figure 4-2 Spherical aberration, field curvature and distortion of the optical system.

[0091] Figure 4-8 Shown according to Figure 4-2 Diagram of lateral aberration of the optical system.

[0092] Figure 4-9 Shown according to Figure 4-3 Spherical aberration, field curvature and distortion of the optical system.

[0093] Figure 4-10 Shown according to Figure 4-3 Diagram of lateral aberration of the optical system.

[0094] Figure 5-1A schematic cross-sectional view of an optical system provided by a fifth example of the present invention when photographing at an infinite position in a first state is shown.

[0095] Figure 5-2 A schematic cross-sectional view of an optical system provided by a fifth example of the present invention when photographing at a minimum object distance in a first state is shown.

[0096] Figure 5-3 A schematic cross-sectional view of an optical system provided by a fifth example of the present invention when photographing at an infinite position in a second state is shown.

[0097] Figure 5-4 A schematic cross-sectional view of an optical system provided by a fifth example of the present invention is shown, the optical system illustrating the bending direction of the reflective element with respect to the optical axis.

[0098] Figure 5-5 Shown according to Figure 5-1 Spherical aberration, field curvature and distortion of the optical system.

[0099] Figure 5-6 Shown according to Figure 5-1 Diagram of lateral aberration of the optical system.

[0100] Figure 5-7 Shown according to Figure 5-2 Spherical aberration, field curvature and distortion of the optical system.

[0101] Figure 5-8 Shown according to Figure 5-2 Diagram of lateral aberration of the optical system.

[0102] Figure 5-9 Shown according to Figure 5-3 Spherical aberration, field curvature and distortion of the optical system.

[0103] Figure 5-10 Shown according to Figure 5-3 Diagram of lateral aberration of the optical system.

[0104] Figure 6 A schematic diagram of an electronic device provided by an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0105] The following will describe an embodiment of the variable optical system of the present invention with reference to the accompanying drawings and optical data. Such a variable optical system can be applied to cameras of electronic devices such as mobile terminal devices.

[0106] The variable optical system according to the present invention has positive refractive power as a whole. The variable optical system includes: a first lens group, the first lens group has the positive refractive power and includes at least four aspherical surfaces; the first lens group can move within a moving range along the optical axis direction; a second lens group, including at least four aspherical surfaces, the second lens group is movable and is configured to be located on the optical axis or outside the optical path; a third lens group. The variable optical system switches between a first state and a second state. In the first state, the first lens group moves from a position close to the image side to a position close to the object side so as to focus from infinity to a close object, the second lens group is outside the optical path and is not used for image formation, and the third lens group is located on the optical axis and close to the first lens group. In the second state, the second lens group is located on the optical axis and inserted into a part of the space generated by the first lens group moving to the object side in the first state, and is used for image formation as a part of the variable optical system.

[0107] Other embodiments of the present invention are provided below. It should be noted that the numbers used in the following sections do not necessarily need to follow the numbers used in the previous sections.

[0108] Embodiment 1: A variable optical system having an overall positive refractive power, comprising:

[0109] a first lens group, the first lens group having the positive refractive power and including at least four aspherical surfaces, the first lens group being movable within a movable range along the optical axis direction;

[0110] a second lens group, the second lens group including at least four aspherical surfaces, the second lens group being movable and configured to be located on the optical axis or outside the optical path;

[0111] The third lens group,

[0112] wherein the variable optical system switches between a first state and a second state, and

[0113] In the first state, the first lens group moves from a position close to the image side to a position close to the object side so as to focus from infinity to a close object, the second lens group is outside the optical path and is not used for image formation, and the third lens group is located on the optical axis and close to the first lens group;

[0114] In the second state, the second lens group is located on the optical axis and inserted into a part of the space created by the first lens group moving to the object side in the first state, and is used for image formation as a part of the variable optical system.

[0115] Embodiment 2: The variable optical system according to embodiment 1 further comprises:

[0116] The first reflecting element is closer to the object side than the first lens group, and is used to bend the optical axis by about 90 degrees on the optical path from the object side to the image side.

[0117] Embodiment 3: According to the variable optical system of embodiment 1 or 2, the second lens group is used to move in a direction perpendicular to the optical axis and parallel to the longitudinal direction of the imaging element.

[0118] Embodiment 4: According to the variable optical system described in any one of Embodiments 1 to 3, the third lens group is movable, and in the second state, the third lens group is outside the optical path.

[0119] Embodiment 5: According to the variable optical system described in any one of Embodiments 1 to 3, the third lens group is a fixed group and is fixedly located on the optical axis, and in the second state, the third lens group is located on the optical axis and close to the inserted second lens group.

[0120] Embodiment 6: According to the variable optical system of any one of Embodiments 1 to 5, TL1<TL2;

[0121] TL1 represents: the distance from the closest object plane to the image plane of the first lens group in the first state;

[0122] TL2 represents: the distance from the closest object plane of the first lens group to the image plane in the second state.

[0123] Embodiment 7: According to the variable optical system described in any one of Embodiments 1 to 6, the second lens group has negative refractive power.

[0124] Embodiment 8: According to any one of Embodiments 1 to 7, the variable optical system, at least one of the lenses constituting the first lens group has a non-circular shape and different effective lengths in the long side direction and the short side direction.

[0125] Embodiment 9: The variable optical system according to any one of Embodiments 1 to 8, further comprising:

[0126] The second reflecting element is closer to the image side than the third lens group, and is used to bend the optical axis by about 90 degrees on the image side of the variable optical system.

[0127] Embodiment 10: The variable optical system according to any one of Embodiments 1 to 9, satisfying the following conditions (i) to (iii):

[0128] (i) 0.55<FL1 / EFL1<0.9

[0129] (ii) 0.6<EFL1 / TTL<1.0

[0130] (iii) 0.2<|MAG|<1.0

[0131] Among them, FL1 represents the focal length of the first lens group, EFL1 represents the focal length of the variable optical system in the first state, TTL represents the distance from the surface vertex of the first lens to the image plane on the optical axis when the variable optical system is focused on infinity in the first state, and MAG represents the optical magnification of the variable optical system at the minimum object distance.

[0132] Embodiment 11: A variable optical system according to any one of Embodiments 1 to 10, satisfying the following conditions (iv) and (v):

[0133] (iv) 0.7<|FL2 / EFL1|<2.3

[0134] (v)0.4<|FL3 / EFL2|<2.8

[0135] Among them, FL2 represents the focal length of the second lens group, FL3 represents the focal length of the third lens group, and EFL2 represents the focal length of the variable optical system in the second state.

[0136] Embodiment 12: A variable optical system according to any one of Embodiments 1 to 11, characterized in that the following condition (vi) is satisfied:

[0137] (vi) 0.9<St / MgTTL<2.0

[0138] Wherein, St represents the maximum movement of the first lens group when focusing, and MgTTL represents the total lens length of the second lens group.

[0139] Embodiment 13: An electronic device comprising a variable optical system according to any one of Embodiments 1 to 12.

[0140] In the description of the following embodiments, the variable optical system is also simply referred to as an "optical system".

[0141] Hereinafter, embodiments of the present invention will be described in detail using examples to which specific numerical values ​​are applied with reference to the accompanying drawings.

[0142] Embodiments 1 to 5 of the optical system are described below, as shown in Table 1.

[0143] Table 1

[0144] Example 1 Example 2 Example 3 Example 4 Example 5 EFL1 13.089 11.213 20.580 13.000 10.000 EFL2 19.433 19.493 29.629 6.000 14.800 TTL 15.450 13.000 25.390 13.450 11.170 FL1 9.422 9.111 14.465 9.450 6.090 FL2 –28.138 –8.703 –16.974 15.167 –20.500 FL3 –11.610 –8.804 –14.562 –11.700 -38.140 St 4.000 5.241 6.685 4.000 3.300 MgTTL 3.100 3.541 3.541 3.100 3.400 (i) FL1 / EFL1 0.720 0.813 0.703 0.727 0.609 (ii) EFL1 / TTL 0.847 0.863 0.811 0.967 0.895 (iii)|MAG| 0.60 0.70 0.21 1.00 0.30 (iv)|FL2 / EFL1| 2.150 0.776 0.825 1.167 2.050 (v)|FL3 / EFL2| 0.597 0.452 0.491 1.950 2.577 (vi) St / MgTTL 1.290 1.480 1.888 1.290 0.971

[0145] In Table 1, EFL1 is the focal length of the optical system in the first state, EFL2 is the focal length of the optical system in the second state, TTL represents the distance from the surface vertex of the first lens to the image plane on the optical axis when the optical system is focused at infinity in the first state, MAG is the optical magnification at the minimum object distance of the optical system, FL1 is the focal length of the first lens group, FL2 is the focal length of the second lens group, and FL3 is the focal length of the third lens group. St is the maximum movement of the first lens group when focusing. MgTTL is the total lens length of the second lens group.

[0146] (First example)

[0147] Figure 1-1 A schematic cross-sectional view of an optical system provided by a first example of the present invention focusing on an infinitely distant object in a first state is shown. In the first state, the optical system according to the first example includes, from the object side along the optical axis OA, a first right-angle prism R1 as a first reflecting element, a first lens group G1, a third lens group G3, and a second right-angle prism R2 as a second reflecting element, and includes a second lens group G2 outside the optical path. Similarly, the optical system includes an image sensor, and a cover glass (CG) may be provided on the image sensor.

[0148] Figure 1-2 A schematic cross-sectional view of an optical system provided by a first example of the present invention during focusing on an object at a minimum object distance in a first state is shown. During focusing on an object at a minimum object distance, the first lens group G1 is located on the object side.

[0149] Figure 1-3 A schematic cross-sectional view of an optical system provided by a first example of the present invention focusing on an infinitely distant object in a second state is shown. In the second state, the second lens group G2 is arranged in a space on the optical path formed by moving the first lens group G1 toward the object side.

[0150] Figure 1-4 A schematic cross-sectional view of an optical system provided by a first example of the present invention is shown, wherein the optical system shows the bending direction of the reflective element to the optical axis. As shown in the figure, the first reflective element R1 and the second reflective element R2 can bend the optical axis OA by about 90 degrees. It should be noted that the second lens group G2 is not shown.

[0151] The first reflective element R1 is arranged closer to the object side than the first lens group G1, and bends the optical axis by about 90 degrees on the optical path from the object side to the image side. The second reflective element R2 is arranged closer to the image side than the third lens group G3, and bends the optical axis by about 90 degrees again on the image side. The first lens group G1 has a positive refractive power and acts as a focusing lens group. The first lens group G1 can move within a moving range along the optical axis direction. The position of the third lens group G3 on the optical axis is fixed. The second lens group G2 is inserted into the space on the optical path generated by the first lens group G1 moving toward the object side and the second lens group G2 is removed from the space, thereby switching the optical state of the optical system. In other words, the second lens group G2 is movable and is configured to be located on the optical axis or outside the optical path. The second lens group G2 may have a negative refractive power.

[0152] The first lens group G1 includes three lenses with six aspherical surfaces. The third lens group G3 includes three lenses with six aspherical surfaces. The second lens group G2 includes four lenses with eight aspherical surfaces.

[0153] Figure 1-1 1 shows a first state where the second lens group G2 is outside the optical path. In the first state, Figure 1-2 As shown, by moving the first lens group G1 toward the object side, focusing can be performed from infinity to a short-distance object. Figure 1-3 The second state in which the second lens group G2 is inserted into the space on the optical path between the first lens group G1 and the third lens group G3, which space is generated by moving the first lens group G1 toward the object side, is shown. As described above, the optical system according to this example can be switched between the first state and the second state by inserting or removing the second lens group G2 in the space on the optical path between the first lens group G1 and the third lens group G3. In this example, the focal length of the second state is longer than that of the first state, and the optical system functions as a lens on the more telephoto side in the second state. Also in the second state, focusing can be performed by moving the first lens group G1 along the optical axis.

[0154] Thus, in the first state, the first lens group G1 moves from a position close to the image side to a position close to the object side so as to focus from infinity to a near object, the second lens group G2 is outside the optical path and is not used for image formation, and the third lens group G3 is located on the optical axis and close to the first lens group. In the second state, the second lens group G2 is located on the optical axis and inserted into a part of the space created by the first lens group G1 moving to the object side in the first state, and is used for image formation as part of the variable optical system. In the example, the third lens group G3 is a fixed group and is fixedly located on the optical axis, and in the second state, the third lens group G3 is located on the optical axis and close to the inserted second lens group.

[0155] In addition, the optical system may satisfy the condition TL1<TL2, where TL1 represents the distance from the closest object plane of the first lens group G1 to the image plane in the first state; and TL2 represents the distance from the closest object plane of the first lens group G1 to the image plane in the second state. The same is true for other examples.

[0156] Table 1-1 shows the focal length, F number, and image height of the optical system according to the present example in the first state (position 1) and the second state (position 2).

[0157] (Table 1-1)

[0158]

[0159] Table 1-2 shows lens data in the first state of the optical system according to the present example, specifically, the curvature radius R of each optical surface and the lens thickness or power D, and the refractive index nd and Abbe number vd (d-line) at a wavelength of 587.56 nm.

[0160] (Table 1-2)

[0161]

[0162]

[0163] Table 1-3 shows lens data in the second state of the optical system according to the present example, specifically, the radius of curvature R of each optical surface and the lens thickness or power D, and the refractive index nd and Abbe number vd (d-line) at a wavelength of 587.56 nm.

[0164] (Table 1-3)

[0165]

[0166]

[0167] Table 1-4 shows the lens thickness or degree D of D0, D2 and D8 in Table 1-2 and Table 1-3. Table 1-4 shows data of infinity (INF) and minimum object distance (MOD).

[0168] (Table 1-4)

[0169]

[0170] Tables 1 to 5 show the aspheric coefficient of each optical surface in the first state of the optical system according to the present example. The aspheric profile is expressed by the following equation.

[0171]

[0172] Among them, z is the arc of the aspherical surface, c is the curvature at the vertex, k is the quadratic constant, r is the radial distance, and A is the aspherical coefficient.

[0173] (Table 1-5)

[0174]

[0175] Table 1-6 shows the aspherical coefficient of each optical surface in the second state of the optical system according to the present example.

[0176] (Table 1-6)

[0177]

[0178]

[0179] Figure 1-5 Shown according to Figure 1-1 The spherical aberration, field curvature and distortion of the optical system for each wavelength.

[0180] Figure 1-6 Shown according to Figure 1-1 Diagram of lateral aberration of the optical system.

[0181] Figure 1-7 Shown according to Figure 1-2 The spherical aberration, field curvature and distortion of the optical system for each wavelength.

[0182] Figure 1-8 Shown according to Figure 1-2 Diagram of lateral aberration of the optical system.

[0183] Figure 1-9 Shown according to Figure 1-3 The spherical aberration, field curvature and distortion of the optical system for each wavelength.

[0184] Figure 1-10 Shown according to Figure 1-3 Diagram of lateral aberration of the optical system.

[0185] Therefore, from Figure 1-5 to Figure 1-10 It can be seen that each aberration is well corrected in the optical system according to this example.

[0186] (Second example)

[0187] Figure 2-1 A schematic cross-sectional view of an optical system provided by a second example of the present invention at an infinite position in a first state is shown. In the first state, the optical system according to the second example includes a first right angle prism R1 as a first reflecting element, a first lens group G1 and a third lens group G3 from the object side along the optical axis OA, and includes a second lens group G2 outside the optical path. Also, the optical system includes an image sensor, and a cover glass (CG) may be provided on the image sensor.

[0188] Figure 2-2 A schematic cross-sectional view of an optical system provided by a second example of the present invention in a first state at a minimum object distance position is shown. In the optical system at the minimum object distance position, the first lens group G1 is located on the object side.

[0189] Figure 2-3 A schematic cross-sectional view of an optical system provided by a second example of the present invention at an infinite position in a second state is shown. In the second state, the second lens group G2 is arranged in a space on the optical path, the space being formed by moving the first lens group G1 toward the object side and moving the third lens group G3 outside the optical path.

[0190] Figure 2-4 A schematic cross-sectional view of an optical system provided by a second example of the present invention is shown, wherein the optical system shows the bending direction of the reflective element to the optical axis. As shown in the figure, the first reflective element R1 can bend the optical axis OA by about 90 degrees. It should be noted that the second lens group G2 is not shown.

[0191] The first reflective element R1 is arranged closer to the object side than the first lens group G1, and bends the optical axis by about 90 degrees on the optical path from the object side to the image side. The first lens group G1 has positive refractive power and acts as a focusing lens group. The first lens group G1 can move within a moving range along the optical axis direction. The third lens group G3 is inserted into the optical path, and the third lens group G3 is removed from the optical path to switch the optical state. The second lens group G2 is inserted into the space on the optical path generated by the movement of the first lens group G1, and the second lens group G2 is removed from the space, thereby switching the optical state of the optical system. The second lens group G2 may have negative refractive power.

[0192] The first lens group G1 includes three lenses with six aspherical surfaces. The third lens group G3 includes three lenses with six aspherical surfaces. The second lens group G2 includes three lenses with six aspherical surfaces.

[0193] In a first state where the third lens group G3 is on the optical path and the second lens group G2 is outside the optical path, as shown in FIG. Figure 2-1 As shown, the first lens group G1 moves toward the object side, and can focus from infinity to a short-distance object. Figure 2-3 As shown, the third lens group G3 is moved out of the optical path, and the second lens group G2 is inserted into the space on the optical path created by the movement of the first lens group G1, thereby switching to the second optical state. That is, in this example, the third lens group G3 is movable and moves out of the optical path in the second state. The focal length in the second state is longer than that in the first state, and the optical system acts as a lens on the more telephoto side in the second state. Also in the second state, focusing can be performed by moving the first lens group G1.

[0194] Table 2-1 shows the focal length, F number, and image height of the optical system according to the present example in the first state (position 1) and the second state (position 2).

[0195] (Table 2-1)

[0196]

[0197] Table 2-2 shows lens data in the first state of the optical system according to the present example, specifically, the radius of curvature R of each optical surface and the lens thickness or power D, and the refractive index nd and Abbe number vd (d-line) at a wavelength of 587.56 nm.

[0198] (Table 2-2)

[0199]

[0200]

[0201] Table 2-3 shows lens data in the second state of the optical system according to the present example, specifically, the radius of curvature R of each optical surface and the lens thickness or power D, and the refractive index nd and Abbe number vd (d-line) at a wavelength of 587.56 nm.

[0202]

[0203] Table 2-4 shows the lens thickness or degree D of D0, D2 and D8 in Table 2-2 and Table 2-3. Table 2-4 shows data of infinity (INF) and minimum object distance (MOD).

[0204] (Table 2-4)

[0205]

[0206] Table 2-5 shows the aspherical coefficient of each optical surface in the first state of the optical system according to the present example.

[0207] (Table 2-5)

[0208]

[0209]

[0210] Table 2-6 shows the aspherical coefficient of each optical surface in the second state of the optical system according to the present example.

[0211] (Table 2-6)

[0212]

[0213] Figure 2-5 Shown according to Figure 2-1 The spherical aberration, field curvature and distortion of the optical system for each wavelength.

[0214] Figure 2-6 Shown according to Figure 2-1 Diagram of lateral aberration of the optical system.

[0215] Figure 2-7 Shown according to Figure 2-2 The spherical aberration, field curvature and distortion of the optical system for each wavelength.

[0216] Figure 2-8 Shown according to Figure 2-2 Diagram of lateral aberration of the optical system.

[0217] Figure 2-9 Shown according to Figure 2-3 The spherical aberration, field curvature and distortion of the optical system for each wavelength.

[0218] Figure 2-10 Shown according to Figure 2-3 Diagram of lateral aberration of the optical system.

[0219] Therefore, from Figure 2-5 to Figure 2-10 It can be seen that each aberration is well corrected in the optical system according to this example.

[0220] (Third Example)

[0221] Figure 3-1 A schematic cross-sectional view of an optical system provided by a third example of the present invention at an infinite position in a first state is shown. In the first state, the optical system according to the third example includes a first right angle prism R1 as a first reflecting element, a first lens group G1, a third lens group G3, and a second right angle prism R2 as a second reflecting element from the object side along the optical axis OA, and includes a second lens group G2 outside the optical path. Similarly, the optical system includes an image sensor, and a cover glass (CG) can be set on the image sensor.

[0222] Figure 3-2 A schematic cross-sectional view of an optical system provided by a third example of the present invention in a first state at a minimum object distance position is shown. In the optical system at the minimum object distance position, the first lens group G1 is located on the object side.

[0223] Figure 3-3 A schematic cross-sectional view of an optical system provided by a third example of the present invention at an infinite position in a second state is shown. In the second state, the second lens group G2 is arranged in a space on the optical path formed by moving the first lens group G1 toward the object side and moving the third lens group G3 outside the optical path.

[0224] Figure 3-4 A schematic cross-sectional view of an optical system provided by a third example of the present invention is shown, wherein the optical system shows the bending direction of the reflective element to the optical axis. As shown in the figure, the first reflective element R1 and the second reflective element R2 can bend the optical axis OA by about 90 degrees. It should be noted that the second lens group G2 is not shown.

[0225] The first reflective element R1 is arranged closer to the object side than the first lens group G1, and bends the optical axis by about 90 degrees on the optical path from the object side to the image side. The second reflective element R2 is arranged closer to the image side than the third lens group G3, and bends the optical axis by about 90 degrees again on the image side. The first lens group G1 has a positive refractive power and acts as a focusing lens group. The first lens group G1 can move within a moving range along the optical axis direction. The third lens group G3 is inserted into the optical path, and the third lens group G3 is removed from the optical path to switch the optical state. The second lens group G2 is also inserted into the optical path, and the second lens group G2 is removed from the optical path to switch the optical state. Specifically, the second lens group G2 is arranged in a space on the optical path, and the space is formed by moving the first lens group G1 to the object side and moving the third lens group G3 outside the optical path. The second lens group G2 may have a negative refractive power.

[0226] The first lens group G1 includes three lenses with six aspherical surfaces. The third lens group G3 includes two lenses with four aspherical surfaces. The second lens group G2 includes two lenses with four aspherical surfaces.

[0227] In a first state where the third lens group G3 is on the optical path and the second lens group G2 is outside the optical path, as shown in FIG. Figure 3-1 As shown, the first lens group G1 moves toward the object side, and can focus from infinity to a short-distance object. Figure 3-3 As shown, the third lens group G3 is moved outside the optical path, and the second lens group G2 is inserted into the space on the optical path instead, thereby switching to the second optical state. The focal length of the second state is longer than that of the first state, and the optical system acts as a lens on the more telephoto side in the second state. Also in the second state, focusing can be performed by moving the first lens group G1.

[0228] Table 3-1 shows the focal length, F number, and image height of the optical system according to the present example in the first state (position 1) and the second state (position 2).

[0229] (Table 3-1)

[0230]

[0231] Table 3-2 shows lens data in the first state of the optical system according to this example, specifically, the curvature radius R of each optical surface and the lens thickness or power D, and the refractive index nd and Abbe number vd (d-line) at a wavelength of 587.56 nm.

[0232] (Table 3-2)

[0233]

[0234]

[0235] Table 3-3 shows lens data in the second state of the optical system according to the present example, specifically, the curvature radius R of each optical surface and the lens thickness or power D, and the refractive index nd and Abbe number vd (d-line) at a wavelength of 587.56 nm.

[0236] (Table 3-3)

[0237]

[0238] Table 3-4 shows the lens thickness or degree D of D0, D2 and D8 in Table 3-2 and Table 3-3. Table 3-4 shows data of infinity (INF) and minimum object distance (MOD).

[0239] (Table 3-4)

[0240]

[0241] Table 3-5 shows the aspherical coefficient of each optical surface in the first state of the optical system according to the present example.

[0242] (Table 3-5)

[0243]

[0244] Table 3-6 shows the aspherical coefficient of each optical surface in the second state of the optical system according to the present example.

[0245] (Table 3-6)

[0246]

[0247] Figure 3-5 Shown according to Figure 3-1 The spherical aberration, field curvature and distortion of the optical system for each wavelength.

[0248] Figure 3-6 Shown according to Figure 3-1 Diagram of lateral aberration of the optical system.

[0249] Figure 3-7 Shown according to Figure 3-2 The spherical aberration, field curvature and distortion of the optical system for each wavelength.

[0250] Figure 3-8 Shown according to Figure 3-2 Diagram of lateral aberration of the optical system.

[0251] Figure 3-9 Shown according to Figure 3-3 The spherical aberration, field curvature and distortion of the optical system for each wavelength.

[0252] Figure 3-10 Shown according to Figure 3-3 Diagram of lateral aberration of the optical system.

[0253] Therefore, from Figure 3-5 to Figure 3-10 It can be seen that each aberration is well corrected in the optical system according to this example.

[0254] (Fourth Example)

[0255] Figure 4-1A schematic cross-sectional view of an optical system provided by a fourth example of the present invention at an infinite position in a first state is shown. In the first state, the optical system according to the fourth example includes, from the object side along the optical axis OA, a first right-angle prism R1 as a first reflecting element, a first lens group G1, a third lens group G3, and a second right-angle prism R2 as a second reflecting element, and includes a second lens group G2 outside the optical path. Similarly, the optical system includes an image sensor, and a cover glass (CG) may be provided on the image sensor.

[0256] Figure 4-2 A schematic cross-sectional view of an optical system provided by a fourth example of the present invention in a first state at a minimum object distance position is shown. In the optical system at the minimum object distance position, the first lens group G1 is located on the object side.

[0257] Figure 4-3 A schematic cross-sectional view of an optical system provided by a fourth example of the present invention at an infinite position in a second state is shown. In the second state, the second lens group G2 is arranged in a space on the optical path formed by moving the first lens group G1 toward the object side.

[0258] Figure 4-4 A schematic cross-sectional view of an optical system provided by a fourth example of the present invention is shown, wherein the optical system shows the bending direction of the reflective element to the optical axis. As shown in the figure, the first reflective element R1 and the second reflective element R2 can bend the optical axis OA by about 90 degrees. It should be noted that the second lens group G2 is not shown.

[0259] The first reflective element R1 is arranged closer to the object side than the first lens group G1, and bends the optical axis by about 90 degrees on the optical path from the object side to the image side. The second reflective element R2 is arranged closer to the image side than the third lens group G3, and bends the optical axis by about 90 degrees again on the image side. The first lens group G1 has positive refractive power and acts as a focusing lens group. The first lens group G1 can move within a moving range along the optical axis direction. The position of the third lens group G3 on the optical axis is fixed. The second lens group G2 is inserted into the space on the optical path generated by the movement of the first lens group G1 to the object side and the second lens group G2 is removed from the space, thereby switching the optical state of the optical system. The second lens group G2 can have negative refractive power.

[0260] The first lens group G1 includes three lenses with six aspherical surfaces. The third lens group G3 includes three lenses with six aspherical surfaces. The second lens group G2 includes four lenses with eight aspherical surfaces.

[0261] In such Figure 4-1The second lens group G2 is shown in a first state outside the optical path, and the first lens group G1 moves toward the object side, as shown in FIG. Figure 4-2 As shown in , you can focus from infinity to short-distance objects. Figure 4-3 As shown, the second lens group G2 is inserted into the space on the optical path between the first lens group G1 and the third lens group G3, which is generated by moving the first lens group G1 toward the object side, thereby switching to the second optical state. The magnification of the second state is greater than that of the first state, and the optical system acts as a macro lens in the second state. Also in the second state, focusing can be performed by moving the first lens group G1.

[0262] Table 4-1 shows the focal length, F number, and image height of the optical system according to this example in the first state (position 1) and the second state (position 2). In this example, the optical magnification becomes -0.95, and the macro function is improved in the second state.

[0263] (Table 4-1)

[0264]

[0265] Table 4-2 shows lens data in the first state of the optical system according to this example, specifically, the curvature radius R of each optical surface and the lens thickness or power D, and the refractive index nd and Abbe number vd (d-line) at a wavelength of 587.56 nm.

[0266] (Table 4-2)

[0267]

[0268]

[0269] Table 4-3 shows lens data in the second state of the optical system according to this example, specifically, the curvature radius R of each optical surface and the lens thickness or power D, and the refractive index nd and Abbe number vd (d-line) at a wavelength of 587.56 nm.

[0270] (Table 4-3)

[0271]

[0272]

[0273] Table 4-4 shows the lens thickness or degree D of D0, D2 and D8 in Table 4-2 and Table 4-3. Table 4-1 shows the data of infinity (INF) and minimum object distance (MOD).

[0274] (Table 4-4)

[0275]

[0276] Table 4-5 shows the aspherical coefficient of each optical surface in the first state of the optical system according to the present example.

[0277] (Table 4-5)

[0278]

[0279]

[0280] Table 4-6 shows the aspherical coefficient of each optical surface in the second state of the optical system according to the present example.

[0281] (Table 4-6)

[0282]

[0283] Figure 4-5 Shown according to Figure 4-1 The spherical aberration, field curvature and distortion of the optical system for each wavelength.

[0284] Figure 4-6 Shown according to Figure 4-1 Diagram of lateral aberration of the optical system.

[0285] Figure 4-7 Shown according to Figure 4-2 The spherical aberration, field curvature and distortion of the optical system for each wavelength.

[0286] Figure 4-8 Shown according to Figure 4-2 Diagram of lateral aberration of the optical system.

[0287] Figure 4-9 Shown according to Figure 4-3 The spherical aberration, field curvature and distortion of the optical system for each wavelength.

[0288] Figure 4-10 Shown according to Figure 4-3 Diagram of lateral aberration of the optical system.

[0289] Therefore, from Figure 4-5 to Figure 4-10 It can be seen that each aberration is well corrected in the optical system according to this example.

[0290] (Fifth Example)

[0291] Figure 5-1A schematic cross-sectional view of an optical system provided by a fifth example of the present invention at an infinite position in a first state is shown. In the first state, the optical system according to the fifth example includes a first right angle prism R1 as a first reflecting element, a first lens group G1 and a third lens group G3 from the object side along the optical axis OA, and includes a second lens group G2 outside the optical path. Also, the optical system includes an image sensor, and a cover glass (CG) may be provided on the image sensor.

[0292] Figure 5-2 A schematic cross-sectional view of an optical system provided by a fifth example of the present invention in a first state at a minimum object distance position is shown. In the optical system at the minimum object distance position, the first lens group G1 is located on the object side.

[0293] Figure 5-3 A schematic cross-sectional view of an optical system provided by a fifth example of the present invention at an infinite position in a second state is shown. In the second state, the second lens group G2 is arranged in a space on the optical path formed by moving the first lens group G1 toward the object side.

[0294] Figure 5-4 A schematic cross-sectional view of an optical system provided by a fifth example of the present invention is shown, wherein the optical system shows the bending direction of the reflective element to the optical axis. As shown in the figure, the first reflective element R1 can bend the optical axis OA by about 90 degrees. It should be noted that the second lens group G2 is not shown.

[0295] The first reflective element R1 is arranged closer to the object side than the first lens group G1, and bends the optical axis by about 90 degrees on the optical path from the object side to the image side. The first lens group G1 has positive refractive power and acts as a focusing lens group. The first lens group G1 can move within a moving range along the optical axis direction. The position of the third lens group G3 on the optical axis is fixed. The second lens group G2 is inserted into the space on the optical path generated by the movement of the first lens group G1 to the object side and the second lens group G2 is removed from the space, thereby switching the optical state of the optical system. The second lens group G2 may have negative refractive power.

[0296] The first lens group G1 includes three lenses with six aspherical surfaces. The third lens group G3 includes three lenses with six aspherical surfaces. The second lens group G2 includes three lenses with six aspherical surfaces.

[0297] In such Figure 5-1 The second lens group G2 is shown in a first state outside the optical path, and the first lens group G1 moves toward the object side, as shown in FIG. Figure 5-2 As shown in , you can focus from infinity to short-distance objects. Figure 5-3As shown, the second lens group G2 is inserted into the space on the optical path between the first lens group G1 and the third lens group G3, which is generated by moving the first lens group G1 toward the object side, thereby switching to the second optical state. The focal length of the second state is longer than that of the first state, so the optical system acts as a lens on the more telephoto side in the second state. Also in the second state, focusing can be performed by moving the first lens group G1 along the optical axis.

[0298] Table 5-1 shows the focal length, F number, and image height of the optical system according to the present example in the first state (position 1) and the second state (position 2).

[0299] (Table 5-1)

[0300]

[0301] Table 5-2 shows lens data in the first state of the optical system according to this example, specifically, the curvature radius R of each optical surface and the lens thickness or power D, and the refractive index nd and Abbe number vd (d-line) at a wavelength of 587.56 nm.

[0302] (Table 5-2)

[0303]

[0304]

[0305] Table 5-3 shows lens data in the second state of the optical system according to this example, specifically, the curvature radius R of each optical surface and the lens thickness or power D, and the refractive index nd and Abbe number vd (d-line) at a wavelength of 587.56 nm.

[0306] (Table 5-3)

[0307]

[0308] Table 5-4 shows the lens thickness or degree D of D0, D2 and D8 in Table 5-2 and Table 5-3. Table 5-4 shows data of infinity (INF) and minimum object distance (MOD).

[0309] (Table 5-4)

[0310]

[0311] Table 5-5 shows the aspherical coefficient of each optical surface in the first state of the optical system according to the present example.

[0312] (Table 5-5)

[0313]

[0314] Table 5-6 shows the aspherical coefficient of each optical surface in the second state of the optical system according to the present example.

[0315] (Table 5-6)

[0316]

[0317]

[0318] Figure 5-5 Shown according to Figure 5-1 The spherical aberration, field curvature and distortion of the optical system for each wavelength.

[0319] Figure 5-6 Shown according to Figure 5-1 Diagram of lateral aberration of the optical system.

[0320] Figure 5-7 Shown according to Figure 5-2 The spherical aberration, field curvature and distortion of the optical system for each wavelength.

[0321] Figure 5-8 Shown according to Figure 5-2 Diagram of lateral aberration of the optical system.

[0322] Figure 5-9 Shown according to Figure 5-3 The spherical aberration, field curvature and distortion of the optical system for each wavelength.

[0323] Figure 5-10 Shown according to Figure 5-3 Diagram of lateral aberration of the optical system.

[0324] Therefore, from Figure 5-5 to Figure 5-10 It can be seen that each aberration is well corrected in the optical system according to this example.

[0325] Figure 6 An electronic device 1000 provided by an embodiment of the present invention is shown. The electronic device 1000 has a camera 100 equipped with the above optical system and a graphics processing unit (GPU) 200. The camera 100 is used to convert an image into digital image data via the optical system of the present invention, and input the digital image data to the GPU 200. The GPU 200 is used to process the digital image data received from the camera 100.

[0326] exist Figure 6In the embodiment, the electronic device 1000 includes two cameras 100, but the number of cameras can be one, three, or more than three. In the electronic device 1000, at least one camera can implement the optical system of the present invention.

[0327] Although embodiments of the present invention have been described in detail for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and intent of the invention as disclosed in the accompanying claims.

Claims

1. A variable optical system having overall positive refractive power, characterized in that: include: a first lens group, the first lens group having the positive refractive power and including at least four aspherical surfaces, the first lens group being movable within a movable range along the optical axis direction; a second lens group, the second lens group including at least four aspherical surfaces, the second lens group being movable and configured to be located on the optical axis or outside the optical path; The third lens group, wherein the variable optical system switches between a first state and a second state, and In the first state, the first lens group moves from a position close to the image side to a position close to the object side so as to focus from infinity to a close object, the second lens group is outside the optical path and is not used for image formation, and the third lens group is located on the optical axis and close to the first lens group; In the second state, the second lens group is located on the optical axis and inserted into a part of the space created by the first lens group moving to the object side in the first state, and is used for image formation as a part of the variable optical system.

2. The variable optical system according to claim 1, characterized in that: Also includes: The first reflecting element is closer to the object side than the first lens group, and is used to bend the optical axis by about 90 degrees on the optical path from the object side to the image side.

3. The variable optical system according to claim 1 or 2, characterized in that: The second lens group is used to move perpendicular to the optical axis and parallel to the longitudinal direction of the imaging element.

4. The variable optical system according to any one of claims 1 to 3, characterized in that: The third lens group is movable, and in the second state, the third lens group is outside the optical path.

5. The variable optical system according to any one of claims 1 to 3, characterized in that: The third lens group is a fixed group and is fixedly located on the optical axis. In the second state, the third lens group is located on the optical axis and close to the inserted second lens group.

6. The variable optical system according to any one of claims 1 to 5, characterized in that: TL1<TL2; TL1 represents: the distance from the closest object plane to the image plane of the first lens group in the first state; TL2 represents: the distance from the closest object plane of the first lens group to the image plane in the second state.

7. The variable optical system according to any one of claims 1 to 6, characterized in that: The second lens group has negative refractive power.

8. The variable optical system according to any one of claims 1 to 7, characterized in that: At least one of the lenses constituting the first lens group has a non-circular shape and has different effective lengths in the long-side direction and the short-side direction.

9. The variable optical system according to any one of claims 1 to 8, characterized in that: Also includes: The second reflecting element is closer to the image side than the third lens group, and is used to bend the optical axis by about 90 degrees on the image side of the variable optical system.

10. The variable optical system according to any one of claims 1 to 9, characterized in that: The following conditions (i) to (iii) are met: (i) 0.55<FL1 / EFL1<0.9 (ii) 0.6<EFL1 / TTL<1.0 (iii) 0.2<|MAG|<1.0 Among them, FL1 represents the focal length of the first lens group, EFL1 represents the focal length of the variable optical system in the first state, TTL represents the distance from the surface vertex of the first lens to the image plane on the optical axis when the variable optical system is focused on infinity in the first state, and MAG represents the optical magnification of the variable optical system at the minimum object distance.

11. The variable optical system according to any one of claims 1 to 10, characterized in that: The following conditions (iv) and (v) are met: (iv) 0.7<|FL2 / EFL1|<2.3 (v)0.4<|FL3 / EFL2|<2.8 Among them, FL2 represents the focal length of the second lens group, FL3 represents the focal length of the third lens group, and EFL2 represents the focal length of the variable optical system in the second state.

12. The variable optical system according to any one of claims 1 to 11, characterized in that: The following conditions (vi) are met: (vi) 0.9<St / MgTTL<2.0 Wherein, St represents the maximum movement of the first lens group when focusing, and MgTTL represents the total lens length of the second lens group.

13. An electronic device, characterized in that: Comprising a variable optical system according to any one of claims 1 to 12.

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