Zoom lens and imaging device including the same

Abstract

A zoom lens (2) capable of telescopic accommodation comprises a first lens group (G1), a second lens group (G2), and a P lens group (G3) arranged in sequence along an optical axis (C) from the object side to the image side; the first lens group (G1) has a negative refractive power; the second lens group (G2) has a reflective optical element that bends the optical axis (C); when telescopically accommodated, the second lens group (G2) moves toward the image side along the optical axis (C), and at least a portion of the first lens group (G1) is telescopically accommodated in a space created by the movement of the second lens group (G2), thereby achieving a wide angle while achieving thinness and miniaturization during telescopic accommodation.

Description

Technical Field

[0001] The present invention relates to a zoom lens including a plurality of lens groups and an imaging device including the zoom lens. Background Art

[0002] There is a demand for zoom lenses in existing mobile device cameras, such as smartphones. However, due to the difficulty in reducing the thickness and size of zoom lenses, they are rarely installed in mobile device cameras. Therefore, in order to form discrete zoom lenses, existing mobile devices use a system that arranges multiple single-focus cameras with different field of view angles side by side to capture images.

[0003] However, as the number of cameras increases, sensors and circuits also increase with the number of cameras, which not only increases the cost, but also increases the volume with the number of cameras, so there is a problem that mobile devices such as smartphones become larger and heavier as a whole.

[0004] Therefore, an imaging device has been developed that includes a telescopic zoom lens that reduces its size when retracted and stored by relatively moving a portion of an optical element within the same plane perpendicular to the optical axis when switching from a photographic state to a telescopic state (see Patent Document 1).

[0005] like Figures 27A to 27C As shown, the imaging device 100 includes a zoom optical system 101 and an imaging element Se. The zoom optical system 101 includes three lens groups (a first lens group 102, a second lens group 103, and a third lens group 104) arranged in the direction of the optical axis C1 and a low-pass filter 105. In addition, in the zoom optical system 101, when the zoom optical system 101 is retracted and accommodated, the second lens group 103 slides laterally from the optical axis C1 (see FIG. Figure 27B ), the first lens group 102 retreats to the position before the second lens group 103 slides (refer to Figure 27C ). The overall dimension of the zoom optical system 101 in this state (when retracted and accommodated) in the thickness direction is the size of the first lens group 102 and the third lens group 104 combined. In addition, the dimension in the thickness direction is the dimension in the direction connecting the object to be imaged and the lens closest to the object of the zoom optical system 101, which is Figures 27A to 27C The left-right dimensions of the .

[0006] In this zoom optical system 101, when telescopically accommodated, as described above, the second lens group 103 slides laterally from the optical axis C1, and the first lens group 102 retracts to the position before the second lens group 103 slides. Therefore, compared to conventional telescopic zoom optical systems, the number of second lens groups 103 can be used to achieve a reduction in thickness. However, since this zoom optical system 101 also requires dimensions equivalent to the thickness of two lens groups (the first lens group 102 and the third lens group 104) when telescopically accommodated, it cannot be said that sufficient thickness reduction is achieved.

[0007] In addition, if Figure 28 As shown in FIG. 1 , an imaging device 200 has been developed that includes a zoom optical system 201 thinned by bending an optical axis C2 using reflecting prisms (reflective optical elements) 202A and 205A (see Patent Document 2).

[0008] The zoom optical system 201 of the imaging device 200 includes, in order from the object side to the image side, a first lens group 202, a second lens group 203, a third lens group 204, and a fourth lens group 205 along the optical axis C2. The first lens group 202 and the fourth lens group 205 include reflecting prisms 202A and 205A, respectively, thereby achieving a thinner structure. In the zoom optical system 201, the optical axis C2 is bent by the reflecting prisms 202A and 205A to achieve a thinner structure. However, since the distance between the reflecting prisms 202A and 205A (the space where the second lens group 203 and the third lens group 204 are arranged) does not decrease when not capturing an image, it cannot be said that the distance is perpendicular to the thickness direction (the direction from the reflecting prism 202A of the first lens group 202 toward the reflecting prism 205A of the fourth lens group 205): Figure 28 left and right directions) can be fully miniaturized.

[0009] In addition, if Figure 29A and Figure 29B As shown, an imaging device 300 has been developed. This system includes a zoom optical system 301 comprising, in order from the object side to the image side, along an optical axis C3: a first lens group 302 having positive curvature; a second lens group 303 having negative curvature; a reflecting prism (reflective optical element) 304 that bends the optical axis C3; and a subsequent lens group 305 comprising multiple lens groups (see Patent Document 3). In this zoom optical system 301, at least the first lens group 302 and the second lens group 303 move during zooming. During telescopic accommodation, the reflecting prism 304 moves to a position different from that during imaging, and the space created by this movement allows the first lens group 302 and the second lens group 303 to be telescopically accommodated.

[0010] In the zoom optical system 301, the first lens group 302 and the second lens group 303 are accommodated in the space vacated by the movement of the reflecting prism 304 when the zoom optical system 301 is telescopically accommodated, thereby achieving a thinner structure when not photographing. However, since the first lens group 302 and the second lens group 303 are telescopically accommodated (see FIG. Figure 29B ), so the size in the thickness direction (in Figure 29B The left-right dimension in the zoom optical system 301 needs to be at least the size of the two lens groups 302 and 303 combined, which cannot achieve sufficient thickness reduction. In addition, in this zoom optical system 301, since the first lens group 302 has a positive refractive index, it is difficult to achieve a wide angle.

[0011] Prior art literature

[0012] Patent Literature

[0013] Patent Document 1: Japanese Patent No. 4520190

[0014] Patent Document 2: Japanese Patent No. 5551055

[0015] Patent Document 3: Japanese Patent No. 4790052 Summary of the Invention

[0016] Problems to be solved by the invention

[0017] Therefore, an object of the present invention is to provide a zoom lens capable of achieving a wider angle of view while achieving thickness reduction and miniaturization during telescopic storage, and an imaging device including the zoom lens.

[0018] Solutions for solving problems

[0019] The zoom lens of the present invention is a zoom lens that can be telescopically accommodated.

[0020] It comprises a first lens group, a second lens group, and a P lens group in order from the object side to the image side along the optical axis;

[0021] The first lens group has negative refractive power;

[0022] The second lens group has a reflective optical element that bends the optical axis;

[0023] During telescopic accommodation, the second lens group moves along the optical axis toward the image side, and at least a portion of the first lens group is telescopically accommodated in a space created by the movement of the second lens group.

[0024] The P lens group has positive refractive power;

[0025] When zooming from wide angle to telephoto,

[0026] At least the first lens group of the first lens group and the second lens group moves along the optical axis to reduce the distance between the first lens group and the second lens group;

[0027] The P lens group moves to reduce the distance between the P lens group and the second lens group;

[0028] The position of the second lens group on the optical axis relative to the image plane may be fixed.

[0029] The zoom lens includes an I lens group, the I lens group being arranged closer to the image side than the P lens group, and having a fixed position relative to the image plane on the optical axis when zooming from the wide-angle end to the telephoto end;

[0030] The I lens group may further include a reflective optical element, which is arranged on the object side of the image plane of the zoom lens and bends the optical axis.

[0031] In addition, in the zoom lens,

[0032] When the focal length of the first lens group is set to f1 and the focal length at the wide-angle end is set to fw, the following conditions can be satisfied:

[0033] -6.000≤f1 / fw≤-1.500.

[0034] In addition, in the zoom lens,

[0035] When the focal length of the P lens group is set to fP, the focal length at the wide-angle end is set to fw, and the focal length at the telephoto end is set to ft, the following conditions can be satisfied:

[0036] 0.500≤fP / √(fw×ft)≤2.500.

[0037] In addition, in the zoom lens,

[0038] When the movement amount of the first lens group from the wide-angle end to the telephoto end (positive on the image side) is set to m1, the focal length at the wide-angle end is set to fw, and the focal length at the telephoto end is set to ft, the following conditions are satisfied:

[0039] 0.800≤m1 / √(fw×ft)≤2.500.

[0040] In addition, in the zoom lens,

[0041] When the focal length of the first lens group is set to f1 and the focal length of the P lens group is set to fP, the following conditions can be satisfied:

[0042] -5.000≤f1 / fP≤-0.500.

[0043] In addition, in the zoom lens,

[0044] When the focal length at the telephoto end is set to ft, the focal length at the wide-angle end is set to fw, the lateral magnification of the P lens group in the infinity focus at the telephoto end is set to bPt, and the lateral magnification of the P lens group in the infinity focus at the wide-angle end is set to bPw, the following conditions are satisfied:

[0045] 0.200≤|(ft / fw) / (bPt / bPw)|≤4.000.

[0046] In addition, in the zoom lens,

[0047] When the focal length at the wide-angle end is set to fw, the focal length at the telephoto end is set to ft, and the focal length of the second lens group is set to f2, the following conditions are satisfied:

[0048] -1.000≤√(fw×ft) / f2≤2.000.

[0049] Furthermore, the imaging device of the present invention includes:

[0050] Any of the above zoom lenses, and

[0051] An imaging element is arranged at an image plane position of the zoom lens. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 Schematic diagram showing the configuration of the imaging device according to this embodiment, showing a photographing state.

[0053] Figure 2 1 is a schematic diagram showing the configuration of the imaging device, and is a diagram showing a state in which a zoom lens is stored.

[0054] Figure 3A 1 is a diagram showing the lens configuration of the zoom lens of Example 1 in the wide-angle end state.

[0055] Figure 3B 1 is a diagram showing the lens configuration of the zoom lens of Example 1 at an intermediate focal position.

[0056] Figure 3C 1 is a diagram showing the lens configuration of the zoom lens according to Example 1 in the telephoto end state.

[0057] Figure 4 1 and 2 are longitudinal aberration diagrams of the zoom lens of Example 1 in the wide-angle end state.

[0058] Figure 5 1 and 2 are longitudinal aberration diagrams of the zoom lens of Example 1 at an intermediate focal position.

[0059] Figure 61 and 2 are longitudinal aberration diagrams of the zoom lens of Example 1 in the telephoto end state.

[0060] Figure 7A 1 is a diagram showing the lens configuration of the zoom lens of Example 2 in the wide-angle end state.

[0061] Figure 7B This is a lens configuration diagram of the zoom lens of Example 2 at an intermediate focal position.

[0062] Figure 7C 1 is a diagram showing the lens configuration of the zoom lens of Example 2 in the telephoto end state.

[0063] Figure 8 1 and 10 are longitudinal aberration diagrams of the zoom lens of Example 2 in the wide-angle end state.

[0064] Figure 9 1 and 2 are longitudinal aberration diagrams of the zoom lens of Example 2 at an intermediate focal position.

[0065] Figure 10 1 and 2 are longitudinal aberration diagrams of the zoom lens of Example 2 in the telephoto end state.

[0066] Figure 11A 1 is a diagram showing the lens configuration of the zoom lens of Example 3 in the wide-angle end state.

[0067] Figure 11B This is a lens configuration diagram of the zoom lens of Example 3 at an intermediate focal position.

[0068] Figure 11C 1 is a diagram showing the lens configuration of the zoom lens of Example 3 in the telephoto end state.

[0069] Figure 12 Graphs showing longitudinal aberrations of the zoom lens of Example 3 at the wide-angle end state.

[0070] Figure 13 1 and 2 are longitudinal aberration diagrams of the zoom lens of Example 3 at an intermediate focal position.

[0071] Figure 14 1 and 2 are longitudinal aberration diagrams of the zoom lens of Example 3 in the telephoto end state.

[0072] Figure 15A 1 is a diagram showing the lens configuration of the zoom lens of Example 4 in the wide-angle end state.

[0073] Figure 15B This is a lens configuration diagram of the zoom lens of Example 4 at an intermediate focal position.

[0074] Figure 15C 4 is a diagram showing the lens configuration of the zoom lens of Example 4 in the telephoto end state.

[0075] Figure 16 1 and 10 are longitudinal aberration diagrams of the zoom lens of Example 4 in the wide-angle end state.

[0076] Figure 17 1 and 2 are longitudinal aberration diagrams of the zoom lens of Example 4 at an intermediate focal position.

[0077] Figure 18 1 and 10 are longitudinal aberration diagrams of the zoom lens of Example 4 in the telephoto end state.

[0078] Figure 19A This is a diagram showing the lens configuration of the zoom lens of Example 5 in the wide-angle end state.

[0079] Figure 19B This is a lens configuration diagram of the zoom lens of Example 5 at an intermediate focal position.

[0080] Figure 19C 1 is a diagram showing the lens configuration of the zoom lens of Example 5 in the telephoto end state.

[0081] Figure 20 1 and 10 are longitudinal aberration diagrams of the zoom lens of Example 5 in the wide-angle end state.

[0082] Figure 21 1 and 10 are longitudinal aberration diagrams of the zoom lens of Example 5 at an intermediate focal position.

[0083] Figure 22 1 and 10 are longitudinal aberration diagrams of the zoom lens of Example 5 in the telephoto end state.

[0084] Figure 23A This is a diagram showing the lens configuration of the zoom lens of Example 6 in the wide-angle end state.

[0085] Figure 23B This is a lens configuration diagram of the zoom lens of Example 6 at an intermediate focal position.

[0086] Figure 23C 1 is a diagram showing the lens configuration of the zoom lens of Example 6 in the telephoto end state.

[0087] Figure 24 1 and 10 are longitudinal aberration diagrams of the zoom lens of Example 6 in the wide-angle end state.

[0088] Figure 25 1 and 10 are longitudinal aberration diagrams of the zoom lens of Example 6 at an intermediate focal position.

[0089] Figure 26 1 and 10 are longitudinal aberration diagrams of the zoom lens of Example 6 in the telephoto end state.

[0090] Figure 27ASchematic diagram showing the structure of a conventional imaging device, showing a photographing state.

[0091] Figure 27B 1 is a schematic diagram showing the configuration of the imaging device, and is a diagram showing a state in which the zoom lens is being stored.

[0092] Figure 27C 1 is a schematic diagram showing the configuration of the imaging device, and is a diagram showing a state in which a zoom lens is stored.

[0093] Figure 28 Schematic diagram showing the structure of a conventional imaging device.

[0094] Figure 29A Schematic diagram showing the structure of a conventional imaging device, showing a photographing state.

[0095] Figure 29B 1 is a schematic diagram showing the configuration of the imaging device, and is a diagram showing a state in which a zoom lens is stored. DETAILED DESCRIPTION

[0096] An embodiment of the present invention will be described below with reference to the accompanying drawings.

[0097] like Figure 1 and Figure 2 As shown, the imaging device of this embodiment has a folding telescopic zoom lens (zoom optical system) 2. In this zoom lens 2, the first lens group G1 has a negative refractive power, thereby being able to cope with wide angles, and the telescopic portion is only the first lens group G1. In addition, in order to promote thinning, a reflective optical element (I lens group GI) is also arranged on the image side, and the thickness dimension of the imaging device 1 (in the Figure 1 and Figure 2 The left-right dimension in the image sensor 3 is not affected by the outer shape of the image sensor 3. In addition, since the reflective optical element (second lens group G2) slides when being telescopically accommodated, the thickness of the image sensor 1 corresponds only to the maximum effective diameter of the lenses (optical elements) constituting each lens group closer to the image side than the first lens group G1, or the dimension of the first lens group G1 in the thickness direction. As described above, the present structure can achieve both wide angle and thinness. In addition, the dimension in the thickness direction in this embodiment is the dimension in the direction connecting the object to be imaged and the lens closest to the object side of the zoom lens 2, which is in Figure 1 and Figure 2 The left-right dimensions of the .

[0098] Specifically, the imaging device 1 includes a telescopic zoom lens 2, an imaging element 3 positioned on the image plane of the zoom lens 2, and a liquid crystal display 4 that displays imaging (image) data transmitted from the imaging element 3. The imaging element 3 converts the optical image formed by the zoom lens 2 into an electrical signal (imaging data). In this embodiment, the imaging element 3 is an image sensor.

[0099] The zoom lens 2 includes at least a first lens group G1, a second lens group G2, a third lens group (P lens group) G3, and an I lens group GI, in order from the object side to the image side along the optical axis C. The zoom lens 2 of this embodiment includes a first lens group G1, a second lens group G2, a third lens group G3, a fourth lens group G4, and an I lens group GI, in order from the object side to the image side along the optical axis C. In this zoom lens 2, the fourth lens group G4 constitutes a focus lens group F.

[0100] Furthermore, the zoom lens 2 may also be configured without lens group I GI. Furthermore, in the zoom lens 2 of this embodiment, lens groups G1 to GI are named for convenience and also include lens groups consisting of only one optical element (lens, etc.). Furthermore, in the zoom lens 2, when zooming, a division is made between optical elements (lenses, etc.) whose positions on the optical axis C are fixed and optical elements that move along different trajectories. The at least one fixed optical element within the divided area is defined as one lens group, and the at least one moving optical element within the divided area is defined as another lens group.

[0101] The zoom lens 2 has an aperture stop 21 disposed on the image side of the second lens group G2 and a lens barrel 22 that holds the first lens group G1. The lens barrel 22 extends toward the object side during photography (see FIG. Figure 1 ), which is retracted when not taking pictures (refer to Figure 2 ).

[0102] In this zoom lens 2, when zooming from the wide-angle end to the telephoto end during photography, at least the first lens group G1 of the first lens group G1 and the second lens group G2 moves along the optical axis C to reduce the distance between the first lens group G1 and the second lens group G2, and the third lens group G3 moves to reduce the distance between the second lens group G2 and the third lens group G3. Furthermore, the positions of the second lens group G2 and the first lens group G1 relative to the imaging element 3 (the image plane of the zoom lens 2) on the optical axis C are fixed.

[0103] Furthermore, in the zoom lens 2, during telescopic accommodation, for example, in the non-photography state, the second lens group G2 moves toward the image side along the optical axis C, and at least a portion of the first lens group G1 is accommodated and contracted within the space created by the movement of the second lens group G2. Specifically, during telescopic accommodation, at least a portion of the first lens group G1 is accommodated and contracted within the space S where the second lens group G2 is located during photography. In this case, the movement of the lens groups G1 to G4 and the extension and contraction of the lens barrel 22 are performed by various conventionally known mechanisms.

[0104] Hereinafter, each lens group G1 to GI of the zoom lens 2 will be described in detail.

[0105] The first lens group G1 includes a plurality of lenses (optical elements) and has negative refractive power. The second lens group G2 includes a reflective optical element that bends the optical axis C. The reflective optical element in this embodiment is a prism, but any optical element such as a mirror that can bend the optical path (optical axis C) will suffice. The second lens group G2 in this embodiment is composed only of reflective optical elements. The third lens group G3 includes a plurality of lenses (optical elements) and has positive refractive power. The I lens group GI has a reflective optical element P and an optical filter 23, the reflective optical element P is arranged on the object side of the imaging element 3 (the image plane of the zoom lens 2) and bends the optical axis C, and the optical filter 23 is arranged on the image side of the reflective optical element P. The reflective optical element P in this embodiment is a prism, but any optical element such as a mirror that can bend the optical path (optical axis C) will suffice.

[0106] In the zoom lens 2 , when the focal length of the first lens group G1 is f1 and the focal length at the wide-angle end is fw, the following conditions are satisfied:

[0107] -6.000≤f1 / fw≤-1.500…(1).

[0108] By setting the ratio of the focal length of the first lens group G1 to the focal length at the wide-angle end within the range shown in the above formula (1), it is possible to optimize the balance between widening the angle of view at the wide-angle end and improving performance.

[0109] When the ratio is lower than the lower limit value (-6.000) of formula (1), the optical power of the first lens group G1 becomes weak, and it is impossible to obtain the optical power configuration of the retrofocus type, so it is difficult to widen the field of view at the wide-angle end. On the other hand, when the ratio exceeds the upper limit value (-1.500) of formula (1), the optical power of the first lens group G1 becomes strong, and widening becomes easy. However, since it is difficult to correct magnification chromatic aberration, coma aberration, and image plane curvature in the entire area of the zoom range through each lens group G1 to GI, the correction of each aberration is insufficient and high performance cannot be achieved. In this way, in the zoom lens 2, if the optical power of the first lens group G1 is enhanced, the field of view at the wide-angle end can be widened, but on the other hand, aberration correction becomes difficult. In this state, the above formula (1) shows the optimal condition for the focal length f1 of the first lens group G1.

[0110] Furthermore, in the zoom lens 2 of this embodiment, the ratio preferably satisfies:

[0111] -5.500≤f1 / fw≤-1.700;

[0112] More preferably, the following conditions are met:

[0113] -5.000≤f1 / fw≤-2.000.

[0114] In the zoom lens 2, when the focal length of the third lens group (P lens group) G3 is tP, the focal length at the wide-angle end is fw, and the focal length at the telephoto end is ft, the following conditions are satisfied:

[0115] 0.500≤fP / √(fw×ft)≤2.500…(2).

[0116] By setting the ratio of the focal length of the third lens group G3 to the effective focal length of the entire optical system (zoom lens) 2 within the range shown in the above formula (2), it is possible to optimize the balance between high performance and miniaturization of the entire optical system.

[0117] When the ratio is lower than the lower limit value (0.500) of formula (2), the optical power of the third lens group G3 becomes stronger, making it difficult to correct spherical aberrations and the like, and high performance cannot be achieved. On the other hand, when the ratio exceeds the upper limit value (2.500) of formula (2), the optical power of the third lens group G3 becomes weaker, thereby lengthening the total optical length and making it difficult to miniaturize the optical system (zoom lens) 2 as a whole. Thus, since the third lens group G3 is a lens group with positive refractive power, if the optical power is increased, the total optical length can be reduced, but on the other hand, aberration correction becomes difficult. In this state, the above formula (2) shows the optimal condition for the focal length of the third lens group G3.

[0118] Furthermore, in the zoom lens 2 of this embodiment, the ratio preferably satisfies:

[0119] 0.650≤fP / √(fw×ft)≤2.000;

[0120] More preferably, the following conditions are met:

[0121] 0.800≤tP / √(fw×ft)≤1.500.

[0122] In the zoom lens 2, when the amount of movement of the first lens group G1 from the wide-angle end to the telephoto end (positive on the image side) is set to m1, the focal length at the wide-angle end is set to fw, and the focal length at the telephoto end is set to ft, the following conditions are satisfied:

[0123] 0.800≤m1 / √(fw×ft)≤2.500…(3).

[0124] By setting the ratio of the movement amount of the first lens group G1 to the effective focal length of the entire optical system (zoom lens) 2 within the range shown in the above formula (3), it is possible to achieve an optimal balance between ensuring the zoom ratio and achieving a thinner lens when retracted and accommodated while ensuring the zoom ratio. The details are as follows.

[0125] When the ratio is lower than the lower limit value (0.800) of formula (3), the movement amount of the first lens group G1 becomes small, making it difficult to ensure a sufficient zoom ratio. On the other hand, when the ratio exceeds the upper limit value (2.500) of formula (3), the movement amount of the first lens group G1 becomes large, making it difficult to thin the mechanical parts such as the cam barrel that constitute the telescopic lens, and it is difficult to reduce the thickness when the telescopic lens is accommodated. In this way, the movement amount of the first lens group G1 that contributes to the zoom is increased by movement, thereby ensuring the zoom ratio, but on the other hand, it is difficult to thin the mechanical parts that constitute the telescopic lens, and further difficult to reduce the thickness when the telescopic lens is accommodated. In this state, the above formula (3) shows the optimal condition for the movement amount of the first lens group G1.

[0126] Furthermore, in the zoom lens 2 of this embodiment, the ratio preferably satisfies:

[0127] 0.900≤m1 / √(fw×ft)≤2.000;

[0128] More preferably, the following conditions are met:

[0129] 1.000≤m1 / √(fw×ft)≤1.800.

[0130] In the zoom lens 2, when the focal length of the first lens group G1 is t1 and the focal length of the third lens group (P lens group) G3 is tP, the following is satisfied:

[0131] -5.000≤f1 / fP≤-0.500…(4)

[0132] By setting the ratio of the focal length of the first lens group G1 to the focal length of the third lens group G3 within the range shown in the above formula (4), it is possible to achieve an optimal balance between widening the angle of view at the wide-angle end and miniaturization of the entire optical system.

[0133] When the ratio is lower than the lower limit value (-5.000) of formula (4), the optical power of the first lens group G1 becomes weak, and it is impossible to obtain the optical power configuration of the retrofocus type, so it is difficult to widen the field angle at the wide-angle end. On the other hand, when the ratio exceeds the upper limit value (-0.500) of formula (4), the optical power of the third lens group G3 becomes weak, and the total optical length becomes longer, making it difficult to miniaturize the optical system (zoom lens) 2 as a whole. In this way, in the optical power ratio of the first lens group G1 and the third lens group G3, if the optical power of the first lens group G1 is weakened, the total optical length can be reduced, but on the other hand, widening the angle becomes difficult. In this state, the above formula (4) shows the optimal conditions for the ratio of the focal lengths of the first lens group G1 and the third lens group G3.

[0134] Furthermore, in the zoom lens 2 of this embodiment, the ratio preferably satisfies:

[0135] -4.000≤f1 / fP≤-0.700;

[0136] More preferably, the following conditions are met:

[0137] -3.000≤f1 / fP≤-0.900.

[0138] Furthermore, in the zoom lens 2, when the focal length at the telephoto end is ft, the focal length at the wide-angle end is fw, the lateral magnification of the third lens group (P lens group) G3 in focus at infinity at the telephoto end is bPt, and the lateral magnification of the third lens group (P lens group) G3 in focus at infinity at the wide-angle end is bPw, the following conditions are satisfied:

[0139] 0.200≤|(ft / fw) / (bPt / bPw)|≤4.000…(5).

[0140] By setting the magnification ratio of the entire optical system (zoom lens) 2 and the third lens group G3 to the range shown in the above formula (5), it is possible to reduce the performance degradation of the design performance after assembly caused by the simplification and miniaturization of the zoom mechanism and the relative decentration of the lens groups G1 to G1. The details are as follows.

[0141] When the ratio is lower than the lower limit value (0.200) of formula (5), the lens groups other than the third lens group G3 need to reduce the magnification of the lens group when changing the magnification from the wide-angle end to the telephoto end, so it is difficult to reduce and miniaturize the lens groups and the number of lens pieces. On the other hand, when the ratio exceeds the upper limit value (4.000) of formula (5), the lens groups other than the third lens group G3 need to increase the magnification of the lens group, so there are many lens groups that move when changing the magnification, and the amount of movement is also large, so it is difficult to miniaturize. Therefore, by effectively using the magnification change accompanying the movement of the third lens group G3 to optimize the magnification ratio, a lens group that is fixed relative to the image plane when changing the magnification is set. As a result, compared with a lens in which many lens groups move when changing the magnification, it is possible to reduce the performance degradation of the design performance after assembly caused by the simplification and miniaturization of the zoom mechanism and the relative decentration of each lens group. In this state, the above formula (5) shows the optimal condition for the magnification change of the P lens group.

[0142] Furthermore, in the zoom lens 2 of this embodiment, the ratio preferably satisfies:

[0143] 0.300≤|(ft / fw) / (bPt / bPw)|≤3.000;

[0144] More preferably, the following conditions are met:

[0145] 0.400≤|(ft / fw) / (bPt / bPw)|≤2.000.

[0146] In the zoom lens 2, when the focal length at the wide-angle end is fw, the focal length at the telephoto end is ft, and the focal length of the second lens group G2 is f2, the following is satisfied:

[0147] -1.000≤√(fw×ft) / f2≤2.000…(6).

[0148] By setting the ratio of the effective focal length of the entire lens system to the focal length of the second lens group within the range shown in the above formula (6), it is possible to optimize the balance between high performance and widening the angle of view at the wide-angle end.

[0149] When the ratio is lower than the lower limit (-1.000) of formula (6), since the second lens group G2 has a strong negative optical power, it is necessary to configure a lens group with strong positive optical power in the lens group closer to the image side than the second lens group G2. As a result, it is difficult to correct spherical aberrations, etc., and high performance cannot be achieved. On the other hand, when the ratio exceeds the upper limit (2.000) of formula (6), since the second lens group G2 has a strong positive optical power, it is impossible to obtain a retrofocus optical power configuration, making it difficult to widen the field of view at the wide-angle end. In this state, the above formula (6) shows the optimal condition for the focal length of the second lens group G2.

[0150] In addition, when the second lens group G2 has no optically divergent or converging power, in the above formula (6), f2 is set to ∞, and the calculation result (the ratio) is 0.

[0151] In the zoom lens 2 of this embodiment, the ratio preferably satisfies:

[0152] -0.500≤√(fw×ft) / f2≤1.750;

[0153] More preferably, the following conditions are met:

[0154] -0.200≤√(fw×ft) / f2≤1.500.

[0155] In the zoom lens 2 constructed as described above, the first lens group G1 has negative refractive power, and the second lens group G2 includes a reflective optical element that bends the optical axis C. Furthermore, during telescopic accommodation, the second lens group G2 moves toward the image side along the optical axis C, and the first lens group G1 is accommodated in the space S created by the movement of the second lens group G2. This arrangement of the first lens group G1, which has negative refractive power, closest to the object facilitates achieving a retrofocus optical power configuration, enabling a wider angle of view by shortening the focal length at the wide-angle end.

[0156] Furthermore, the second lens group G2 (reflecting optical element) bends the optical path (optical axis C) of light incident from the object side, and when telescopically accommodated, the second lens group G2 moves toward the image side along the optical axis C, and the first lens group G1 moves in the space S generated by this movement (i.e., the position of the second lens group G2 in the photographic state), thereby enabling the overall thinning of the zoom lens 2 (miniaturization of the size in the thickness direction).

[0157] That is, in the zoom lens 2, while the second lens group G2 bends the optical path, thereby achieving a thinner profile (smaller thickness dimension) of the zoom lens 2, the first lens group G1 can be telescopically accommodated, thereby achieving further thinning (smaller thickness dimension) of the zoom lens 2 when not capturing images (when telescopically stored). Furthermore, when telescopically accommodated, the second lens group G2 moves toward the image side along the second optical axis (i.e., the optical axis after bending), while the first lens group G1 moves along the first optical axis (the optical axis before bending) to be telescopically accommodated in the space S. As a result, the second lens group G2 and the first lens group G1 can move independently in two different directions, ensuring both freedom of movement and space for movement.

[0158] Furthermore, when the zoom lens 2 is retracted and accommodated, the second lens group G2 moves toward the image side along the optical axis C, that is, moves to reduce the intervals between the lens groups required for the zoom lens 2. This minimizes the volume and thus achieves miniaturization of the zoom lens 2 as a whole (specifically, in FIG. Figure 1 and Figure 2 (miniaturization of the dimensions in the vertical direction).

[0159] Furthermore, in the zoom lens 2 of this embodiment, the third lens group (P lens group) G3 has positive refractive power. Furthermore, when zooming from the wide-angle end to the telephoto end of the zoom lens 2, at least the first lens group G1 of the first lens group G1 and the second lens group G2 moves along the optical axis C to reduce the distance between the first lens group G1 and the second lens group G2, while the third lens group (P lens group) G3 moves to reduce the distance between the second lens group G2 and the second lens group G2. The positions of the second lens group G2 and the I lens group G1 relative to the imaging element 3 (the image plane of the zoom lens 2) on the optical axis C are fixed. Thus, the third lens group G3, which has positive refractive power, is arranged closer to the image side than the second lens group G2, whose position relative to the imaging element 3 (the image plane) on the optical axis C is fixed. By making the first lens group G1 and the third lens group G3 movable during zooming, the magnification of each lens group can be changed, enabling efficient zooming of the zoom lens 2. In other words, the high performance of the zoom lens 2 can be achieved.

[0160] In addition, in the zoom lens 2 of this embodiment,

[0161] Lens group I GI includes a reflective optical element, which is positioned on the object side of the imaging element 3 (the image plane of the zoom lens 2) and bends the optical axis C. Therefore, because lens group I GI (the reflective optical element), which is positioned closer to the image plane than second lens group G2, bends optical axis C extending from second lens group G2, the portion of the zoom lens 2 from second lens group G2 to lens group I GI can be prevented from increasing in thickness, regardless of the size of the imaging element 3 positioned at the image plane. In other words, the thickness of the zoom lens 2 and imaging device 1 does not affect the size of the imaging element 3.

[0162] As described above, the zoom lens 2 of this embodiment and the imaging device 1 including the zoom lens 2 can provide a zoom lens capable of achieving a wider angle while achieving thickness reduction and miniaturization during telescopic storage, and an imaging device including the zoom lens.

[0163] Next, Examples 1 to 6 of the zoom lens of the present invention are described. In the following examples, the same reference numerals are used for the components corresponding to the components of the zoom lens 2 of the above embodiment. In the tables of the following examples, r is the radius of curvature, d is the lens thickness or the lens interval, nd is the refractive index of the d-line, and vd represents the refractive index of the d-line.

[0164] The aspheric surface is defined by the following formula 1.

[0165] Formula 1

[0166] z=ch 2 / [1+{1-(1+k)c 2 h 2} 1 / 2 ]+A4h 4 +A6h 6 +A8h 8 +A10h 10 …

[0167] (Where c is the curvature (1 / r), h is the height from the optical axis, k is the cone coefficient, and A4, A6, A8, A10, etc. are the aspheric coefficients of each degree.)

[0168] The longitudinal aberration diagrams show, from the left, spherical aberration (SA (mm)), astigmatism (AST (mm)), and distortion (DIS (%)). In the spherical aberration diagrams, the vertical axis represents the F-number (FNO in the diagrams), the solid line represents the d-line characteristics, the short dashed line represents the F-line characteristics, and the long dashed line represents the C-line characteristics. In the astigmatism diagrams, the vertical axis represents the field angle (w in the diagrams), the solid line represents the sagittal plane characteristics (S in the diagrams), and the dashed line represents the meridional plane characteristics (M in the diagrams). In the distortion diagrams, the vertical axis represents the field angle (w in the diagrams).

[0169] Example 1

[0170] Figure 3A to Figure 3C : is a lens structure diagram of the zoom lens of Example 1. Figure 3A Indicates wide-angle state, Figure 3B Indicates the intermediate focus position state, Figure 3C Indicates the telephoto end state. Figure 3A to Figure 3C , the optical axis is shown in a state where it is not bent. Note that the reference numerals denoting the various components of the zoom lens are the same as the reference numerals denoting the corresponding components of the zoom lens 2 according to the above-described embodiment.

[0171] In the zoom lens of Example 1, the third lens group is lens group P, and the group including the parallel plate glass (optical filter) arranged on the image side is lens group I. Furthermore, in this zoom lens, the positions of the second lens group and lens group I relative to the image plane on the optical axis are fixed during zooming.

[0172] in addition, Figure 4 This is a diagram of longitudinal aberration at the wide-angle end. Figure 5 This is the longitudinal aberration diagram at the intermediate focus position. Figure 6 It is a longitudinal aberration diagram in the telephoto end state. The following Table 1 shows the surface data of each lens, Table 2 shows the aspheric surface data (the aspheric coefficient not displayed is 0.00), Table 3 shows various data, Table 4 shows the zoom lens group data, and Table 5 shows the zoom lens group magnification.

[0173] Table 1

[0174] Polygon data

[0175] Face number r d nd vd 1* 113.148 0.700 1.8513 40.10 2* 6.934 2.202 3 8.575 1.217 1.9229 20.88 4 12.258 d4 5* 13.501 5.500 1.5445 55.96 6* 26.479 d6 (Aperture Stop) 7* 10.980 1.200 1.4971 81.56 8* -10.947 0.200 9 5.400 3.000 1.5831 59.46 10 -23.369 1.000 1.9537 32.32 11 4.551 d11 12* 17.489 0.825 1.5931 37.65 13* -60.350 d13 14 ∞ 5.000 2.0010 29.13 15 ∞ 0.200 16 ∞ 0.300 1.5168 64.20 17 ∞ 0.200

[0176] *Aspherical

[0177] Table 2

[0178]

[0179] Table 3

[0180] Various data

[0181] wide angle middle Telephoto focal length 5.668 9.683 15.086 F-number 2.440 3.126 4.318 Half-view 38.010 23.000 14.989 Lens full length 45.000 36.651 33.789 Back focus 4.903 7.114 10.452 d4 12.250 3.900 1.038 d6 7.393 4.203 0.500 d11 1.996 2.976 3.342 d13 1.818 4.028 7.365

[0182] The zoom ratio is 2.662 and the image height is 4.048.

[0183] Table 4

[0184] Zoom lens group data

[0185] Group Starting face focal length Lens length Lens shift amount 1 1 -13.575 4.119 11.209 2 5 43.812 5.500 0.000 3 7 12.643 5.400 -6.896 4 12 23.604 0.825 -5.549

[0186] Table 5

[0187] Zoom lens ratio

[0188] Group Starting face wide angle middle Telephoto 1 1 0.000 0.000 0.000 2 5 2.439 1.665 1.502 3 7 -0.221 -0.629 -1.368 4 12 0.774 0.681 0.541

[0189] Example 2

[0190] Figures 7A to 7C : is a lens structure diagram of the zoom lens of Example 1. Figure 7A Indicates wide-angle state, Figure 7B Indicates the intermediate focus position state, Figure 7C Indicates the telephoto end state. Figures 7A to 7C , the optical axis is shown in a state where it is not bent. Note that the reference numerals denoting the various components of the zoom lens are the same as the reference numerals denoting the corresponding components of the zoom lens 2 according to the above-described embodiment.

[0191] In the zoom lens of Example 2, the third lens group is lens group P, and the group including the parallel plate glass (optical filter) arranged on the image side is lens group I. Furthermore, in this zoom lens, the positions of the second lens group and lens group I relative to the image plane on the optical axis are fixed during zooming.

[0192] in addition, Figure 8 This is a diagram of longitudinal aberration at the wide-angle end. Figure 9 This is the longitudinal aberration diagram at the intermediate focus position. Figure 10 It is a longitudinal aberration diagram in the telephoto end state. The following Table 6 shows the surface data of each lens, Table 7 shows the aspheric surface data (the aspheric coefficient not displayed is 0.00), Table 8 shows various data, Table 9 shows the zoom lens group data, and Table 10 shows the zoom lens group magnification.

[0193] Table 6

[0194] Polygon data

[0195] Face number r d nd vd 1* 84.713 0.700 1.8513 40.10 2* 8.302 1.824 3 11.733 1.734 1.9229 20.88 4 24.082 d4 5 ∞ 5.500 1.5445 55.96 6 ∞ d6 (Aperture Stop) 7* 6.511 1.860 1.4971 81.56 8* -13.589 0.200 9 5.499 2.312 1.5831 59.46 10 55.255 1.000 1.9537 32.32 11 3.807 d11 12* 15.360 3.000 1.5931 37.65 13* -100.000 d13 14 ∞ 5.000 2.0010 29.13 15 ∞ 0.200 16 ∞ 0.300 1.5168 64.20 17 ∞ 0.200

[0196] *Aspherical

[0197] Table 7

[0198]

[0199] Table 8

[0200] Various data

[0201] wide angle middle Telephoto focal length 5.665 9.578 14.992 F-number 2.440 2.961 4.292 Half-view 37.992 22.999 14.993 Lens full length 50.000 36.985 34.537 Back focus 3.583 4.481 3.601 d4 16.585 3.570 1.123 d6 6.787 4.494 0.500 d11 2.302 3.696 8.570 d13 0.496 1.395 0.515

[0202] The zoom ratio is 2.646 and the image height is 4.048.

[0203] Table 9

[0204] Zoom lens group data

[0205] Group Starting face focal length Lens length Lens shift amount 1 1 -22.161 4.257 15.463 2 5 0.000 5.500 0.000 3 7 11.538 5.372 -6.287 4 12 23.310 3.000 -0.019

[0206] Table 10

[0207] Zoom lens ratio

[0208] Group Starting face wide angle middle Telephoto 1 1 0.000 0.000 0.000 2 5 1.000 1.000 1.000 3 7 -0.330 -0.587 -0.874 4 12 0.774 0.736 0.774

[0209] Example 3

[0210] Figures 11A to 11C : is a lens structure diagram of the zoom lens of Example 1. Figure 11A Indicates wide-angle state, Figure 11B Indicates the intermediate focus position state, Figure 11C Indicates the telephoto end state. Figures 11A to 11C , the optical axis is shown in a state where it is not bent. Note that the reference numerals denoting the various components of the zoom lens are the same as the reference numerals denoting the corresponding components of the zoom lens 2 according to the above-described embodiment.

[0211] In the zoom lens of Example 3, the third lens group is lens group P, and the group including the parallel plate glass (optical filter) arranged on the image side is lens group I. Furthermore, in this zoom lens, the positions of the second lens group and lens group I relative to the image plane on the optical axis are fixed during zooming.

[0212] in addition, Figure 12 This is a diagram of longitudinal aberration at the wide-angle end. Figure 13 This is the longitudinal aberration diagram at the intermediate focus position. Figure 14 It is a longitudinal aberration diagram in the telephoto end state. The following Table 11 shows the surface data of each lens, Table 12 shows the aspheric surface data (the aspheric coefficient not displayed is 0.00), Table 13 shows various data, Table 14 shows the zoom lens group data, and Table 15 shows the zoom lens group magnification.

[0213] Table 11

[0214] Polygon data

[0215] Face number r d nd vd 1* 124.688 0.700 1.8513 40.10 2* 7.080 2.567 3 9.310 1.183 1.9229 20.88 4 13.324 d4 5* 12.643 5.500 1.5445 55.96 6* 24.065 d6 (Aperture Stop) 7* 8.703 1.115 1.4971 81.56 8* -20.876 0.200 9 4.804 1.507 1.4970 81.61 10 296.867 0.200 11 6.127 0.400 2.0010 29.13 12 3.452 d12 13* -11.685 0.961 1.5445 55.96 14* -35.581 d14 15 ∞ 5.000 2.0010 29.13 16 ∞ 0.200 17 ∞ 0.300 1.5168 64.20 18 ∞ 0.200

[0216] *Aspherical

[0217] Table 12

[0218]

[0219] Table 13

[0220] Various data

[0221] wide angle middle Telephoto focal length 5.668 9.658 14.969 F-number 2.440 3.117 4.152 Half-view 38.008 22.997 14.984 Lens full length 45.000 35.837 32.392 Back focus 4.985 7.429 9.676 d4 13.607 4.445 1.000 d6 6.340 3.578 0.500 d12 3.120 3.441 4.274 d14 1.899 4.341 6.585

[0222] The zoom ratio is 2.641 and the image height is 4.048.

[0223] Table 14

[0224] Zoom lens group data

[0225] Group Starting face focal length Lens composition length Lens shift amount 1 1 -13.48 4.450 12.603 2 5 41.627 5.500 0.000 3 7 9.903 3.422 -5.844 4 13 -32.275 0.961 -4.691

[0226] Table 15

[0227] Zoom lens ratio

[0228] Group Starting face wide angle middle Telephoto 1 1 0.000 0.000 0.000 2 5 2.947 1.787 1.557 3 7 -0.121 -0.318 -0.537 4 13 1.183 1.259 1.328

[0229] Example 4

[0230] Figures 15A to 15C : is a lens structure diagram of the zoom lens of Example 1. Figure 15A Indicates wide-angle state, Figure 15B Indicates the intermediate focus position state, Figure 15C Indicates the telephoto end state. Figures 15A to 15C , the optical axis is shown in a state where it is not bent. Note that the reference numerals denoting the various components of the zoom lens are the same as the reference numerals denoting the corresponding components of the zoom lens 2 according to the above-described embodiment.

[0231] In the zoom lens of Example 4, the third lens group is lens group P, and the group including the parallel plate glass (optical filter) arranged on the image side is lens group I. Furthermore, in this zoom lens, the positions of the second lens group and lens group I relative to the image plane on the optical axis are fixed during zooming.

[0232] in addition, Figure 16 This is a diagram of longitudinal aberration at the wide-angle end. Figure 17 This is the longitudinal aberration diagram at the intermediate focus position. Figure 18It is a longitudinal aberration diagram in the telephoto end state. The following Table 16 shows the surface data of each lens, Table 17 shows the aspheric surface data (the aspheric coefficient not displayed is 0.00), Table 18 shows various data, Table 19 shows the zoom lens group data, and Table 20 shows the zoom lens group magnification.

[0233] Table 16

[0234] Polygon data

[0235] Face number r d nd vd 1* 70.881 0.700 1.8513 40.10 2* 9.624 1.101 3 8.447 1.597 1.9229 20.88 4 10.888 d4 5 ∞ 5.500 1.5445 55.96 6 ∞ d6 (Aperture Stop) 7* 5.293 1.051 1.4971 81.56 8* 24.889 0.200 9 5.320 1.382 1.4970 81.61 10 -22.560 0.200 11 4.432 0.405 2.0010 29.13 12 2.881 d12 13* -18.050 0.500 1.5445 55.96 14* 38.459 d14 15 ∞ 5.000 2.0010 29.13 16 ∞ 0.200 17 ∞ 0.300 1.5168 64.20 18 ∞ 0.200

[0236] *Aspherical

[0237] Table 17

[0238]

[0239] Table 18

[0240] wide angle middle Far focal length 6.091 9.812 15.081 F-number 2.440 2.923 3.856 Half-view 37.202 22.888 14.972 Lens full length 45.000 33.779 29.531 Back focus 4.059 5.481 8.478 d4 16.746 5.525 1.277 d6 4.632 3.053 0.500 d12 4.315 4.472 4.032 d14 0.972 2.393 5.387

[0241] The zoom ratio is 2.676 and the image height is 4.048.

[0242] Table 19

[0243] Group Starting face focal length Lens composition length Lens shift amount 1 1 -21.404 3.397 15.465 2 5 0.000 5.500 0.000 3 7 8.851 3.238 -4.137 4 13 -22.395 0.500 -4.419

[0244] Table 20

[0245] Group Starting face wide angle middle Far 1 1 0.000 0.000 0.000 2 5 1.000 1.000 1.000 3 7 -0.239 -0.365 -0.508 4 13 1.190 1.254 1.387

[0246] Example 5

[0247] Figures 19A to 19C : is a lens structure diagram of the zoom lens of Example 1. Figure 19A Indicates wide-angle state, Figure 19B Indicates the intermediate focus position state, Figure 19C Indicates the telephoto end state. Figures 19A to 19C , the optical axis is shown in a state where it is not bent. Note that the reference numerals denoting the various components of the zoom lens are the same as the reference numerals denoting the corresponding components of the zoom lens 2 according to the above-described embodiment.

[0248] In the zoom lens of Example 5, the third lens group is lens group P, and the group including the parallel plate glass (optical filter) arranged on the image side is lens group I. Furthermore, in this zoom lens, the positions of the second lens group and lens group I relative to the image plane on the optical axis are fixed during zooming.

[0249] in addition, Figure 20 This is a diagram of longitudinal aberration at the wide-angle end. Figure 21 This is the longitudinal aberration diagram at the intermediate focus position. Figure 22It is a longitudinal aberration diagram in the telephoto end state. The following Table 21 shows the surface data of each lens, Table 22 shows the aspheric surface data (the aspheric coefficient not displayed is 0.00), Table 23 shows various data, Table 24 shows the zoom lens group data, and Table 25 shows the zoom lens group magnification.

[0250] Table 21

[0251] Polygon data

[0252] Face number r d nd vd 1* 73.189 0.700 1.8513 40.10 2* 8.875 1.391 3 11.844 1.957 1.9229 20.88 4 24.294 d4 5* -40.344 5.500 1.5445 55.96 6* -161.762 d6 (Aperture Stop) 7* 6.614 1.772 1.4971 81.56 8* -12.017 0.200 9 5.676 2.457 1.5831 59.46 10 45.673 1.000 1.9537 32.32 11 3.875 d11 12* 16.235 3.000 1.5931 37.65 13* -100.000 d13 14 ∞ 5.000 2.0010 29.13 15 ∞ 0.200 16 ∞ 0.300 1.5168 64.20 17 ∞ 0.200

[0253] *Aspherical

[0254] Table 22

[0255]

[0256] Table 23

[0257] Various data

[0258] wide angle middle Telephoto focal length 5.639 9.589 14.988 F-number 2.440 2.996 4.358 Half-view 37.993 22.994 14.995 Lens full length 50.000 36.457 33.999 Back focus 3.852 4.308 3.603 d4 17.159 3.617 1.158 d6 6.504 4.288 0.500 d11 1.897 3.657 8.149 d13 0.763 1.219 0.514

[0259] The zoom ratio is 2.658 and the image height is 4.048.

[0260] Table 24

[0261] Zoom lens group data

[0262] Group Starting face focal length Lens composition length Lens shift amount 1 1 -25.413 4.048 16.002 2 5 -100.316 5.500 0.000 3 7 10.597 5.429 -6.004 4 12 24.604 3.000 0.249

[0263] Table 25

[0264] Zoom lens ratio

[0265] Group Starting face wide angle middle Telephoto 1 1 0.000 0.000 0.000 2 5 0.694 0.765 0.780 3 7 -0.412 -0.651 -0.962 4 12 0.775 0.756 0.786

[0266] Example 6

[0267] Figures 23A to 23C : is a lens structure diagram of the zoom lens of Example 1. Figure 23A Indicates wide-angle state, Figure 23B Indicates the intermediate focus position state, Figure 23C Indicates the telephoto end state. Figures 23A to 23C , the optical axis is shown in a state where it is not bent. Note that the reference numerals denoting the various components of the zoom lens are the same as the reference numerals denoting the corresponding components of the zoom lens 2 according to the above-described embodiment.

[0268] In the zoom lens of Example 6, the third lens group is lens group P, and the group including the parallel plate glass (optical filter) arranged on the image side is lens group I. Furthermore, in this zoom lens, the positions of the second lens group and lens group I relative to the image plane on the optical axis are fixed during zooming.

[0269] in addition, Figure 24 This is a diagram of longitudinal aberration at the wide-angle end. Figure 25 This is the longitudinal aberration diagram at the intermediate focus position. Figure 26 It is a longitudinal aberration diagram in the telephoto end state. The following Table 26 shows the surface data of each lens, Table 27 shows the aspheric surface data (the aspheric coefficient not displayed is 0.00), Table 28 shows various data, Table 29 shows the zoom lens group data, and Table 30 shows the zoom lens group magnification.

[0270] Table 26

[0271] Polygon data

[0272] Face number r d nd vd 1* 113.599 0.700 1.8513 40.10 2* 8.716 2.298 3 9.660 1.452 1.9229 20.88 4 14.162 d4 5* 14.773 5.500 1.5445 55.96 6* 10.099 d6 (Aperture Stop) 7* 8.333 1.281 1.4971 81.56 8* -11.524 0.200 9 4.674 1.201 1.4970 81.61 10 38.556 0.200 11 5.340 0.436 2.0010 29.13 12 3.351 d12 13* -14.101 1.000 1.5445 55.96 14* 1402.384 d14 15 ∞ 5.000 2.0010 29.13 16 ∞ 0.200 17 ∞ 0.300 1.5168 64.20 18 ∞ 0.200

[0273] *Aspherical

[0274] Table 27

[0275]

[0276] Table 28

[0277] Various data

[0278] wide angle middle Telephoto focal length 5.752 9.740 15.068 F-number 2.440 3.091 4.292 Half-view 37.979 22.997 14.989 Lens full length 45.000 34.467 31.222 Back focus 4.066 5.425 6.430 d4 14.818 4.285 1.040 d6 5.054 3.054 0.500 d12 4.183 4.823 6.373 d14 0.977 2.337 3.341

[0279] The zoom ratio is 2.620 and the image height is 4.048.

[0280] Table 29

[0281] Zoom lens group data

[0282] Group Starting face focal length Lens length Lens shift amount 1 1 -19.190 4.450 13.778 2 5 -100.176 5.500 0.000 3 7 7.731 3.318 -4.554 4 13 -25.632 1.000 -2.364

[0283] Table 30

[0284] Zoom lens ratio

[0285] Group Starting face wide angle middle Telephoto 1 1 0.000 0.000 0.000 2 5 0.638 0.684 0.699 3 7 -0.397 -0.600 -0.881 4 13 1.184 1.237 1.276

[0286] The values corresponding to the formulas (1) to (6) of the above-mentioned embodiments 1 to 6 are shown in Table 31 below.

[0287] Table 31

[0288] Conditional corresponding value

[0289] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Conditional expression (1) -2.395 -3.912 -2.378 -3.514 -4.506 -3.336 Conditional expression (2) 1.367 1.252 1.075 0.923 1.153 0.830 Conditional expression (3) 1.212 1.678 1.368 1.614 1.740 1.480 Conditional expression (4) -1.074 -1.921 -1.361 -2.418 -2.398 -2.482 Conditional expression (5) 0.430 0.999 0.595 1.165 1.138 1.180 Conditional expression (6) 1.367 0.000 0.221 0.000 -0.092 -0.093 fw 5.668 5.665 5.668 6.091 5.639 5.752 ft 15.086 14.992 14.969 15.081 14.988 15.068 f1 -13.575 -22.161 -13.48 -21.404 -25.413 -19.190 f2 43.812 0.000 41.627 0.000 -100.316 -100.176 fP 12.643 11.538 9.903 8.851 10.597 7.731 m1 11.209 15.463 12.603 15.465 16.002 13.778 mP -6.896 -6.287 -5.844 -4.137 -6.004 -4.554 oeLh -0.221 -0.330 -0.121 -0.239 -0.412 -0.397 oeLh -1.368 -0.874 -0.537 -0.508 -0.962 -0.881

[0290] Although the present invention has been appropriately and fully described above with reference to the accompanying drawings in order to illustrate the present invention, it should be appreciated by those skilled in the art that modifications and / or improvements to the above-described embodiments are readily achievable. Therefore, as long as modifications or improvements implemented by those skilled in the art do not depart from the scope of the claims set forth in the claims, such modifications or improvements should be construed as being included within the scope of the claims.

[0291] Description of Reference Numerals

[0292] 1: Camera device

[0293] 2: Zoom lens

[0294] 22: Lens barrel

[0295] 23: Optical filter

[0296] 3: Camera element

[0297] 4: LCD screen

[0298] 100: Camera

[0299] 101: Zoom Optical System

[0300] 102: First lens group

[0301] 103: Second lens group

[0302] 104: Third lens group

[0303] 105: Low-pass filter

[0304] 200: Camera

[0305] 201: Zoom optical system

[0306] 202: First lens group

[0307] 202A: Reflecting prism

[0308] 203: Second lens group

[0309] 204: Third lens group

[0310] 205: Fourth lens group

[0311] 205A: Reflecting prism

[0312] 300: Camera

[0313] 301: Zoom optical system

[0314] 302: First lens group

[0315] 303: Second lens group

[0316] 304: Reflecting Prism

[0317] 305: Subsequent lens group

[0318] C, C1, C2, C3: Optical axis

[0319] F: Focus lens group

[0320] G1: First lens group

[0321] G2: Second lens group

[0322] G3: The third lens group (P lens group)

[0323] G4: Fourth lens group

[0324] GI:I lens group

[0325] P: Reflective optical element

[0326] S: Space

[0327] Se:Camera element

Claims

1. A zoom lens, characterized in that: It is a zoom lens that can be telescopically accommodated, including: The first lens group, the second lens group, and the P lens group are provided in order from the object side to the image side along the optical axis; The first lens group has negative refractive power; The second lens group has a reflective optical element that bends the optical axis; During telescopic accommodation, the second lens group moves along the optical axis toward the image side, and at least a portion of the first lens group is telescopically accommodated in a space created by the movement of the second lens group. The P lens group has positive refractive power; When zooming from wide angle to telephoto, At least the first lens group of the first lens group and the second lens group moves along the optical axis to reduce the distance between the first lens group and the second lens group; The P lens group moves to reduce the distance between the P lens group and the second lens group; The position of the second lens group on the optical axis relative to the image plane is fixed, Taking the image side as positive, when the movement amount of the first lens group from the wide-angle end to the telephoto end is set to m1, the focal length at the wide-angle end is set to fw, and the focal length at the telephoto end is set to ft, the following is satisfied: 0.800≤m1 / √(fw×ft)≤2.

500.

2. The zoom lens according to claim 1, wherein have: A lens group I is arranged closer to the image side than the lens group P, and its position on the optical axis relative to the image plane is fixed when zooming from the wide-angle end to the telephoto end; The I lens group includes a reflective optical element that is arranged on the object side of the image plane of the zoom lens and bends the optical axis.

3. The zoom lens according to claim 1, wherein When the focal length of the first lens group is set to f1 and the focal length at the wide-angle end is set to fw, the following conditions are satisfied: -6.000≤f1 / fw≤-1.

500.

4. The zoom lens according to claim 1, wherein When the focal length of the P lens group is set to fP, the focal length at the wide-angle end is set to fw, and the focal length at the telephoto end is set to ft, the following conditions are satisfied: 0.500≤fP / √(fw×ft)≤2.

500.

5. The zoom lens according to claim 1, wherein When the focal length of the first lens group is set to f1 and the focal length of the P lens group is set to fP, the following conditions are satisfied: -5.000≤f1 / fP≤-0.

500.

6. The zoom lens according to claim 1, wherein When the focal length at the telephoto end is set to ft, the focal length at the wide-angle end is set to fw, the lateral magnification of the P lens group in the infinity focus at the telephoto end is set to bPt, and the lateral magnification of the P lens group in the infinity focus at the wide-angle end is set to bPw, the following conditions are satisfied: 0.200≤|(ft / fw) / (bPt / bPw)|≤4.

000.

7. The zoom lens according to claim 1, wherein When the focal length at the wide-angle end is set to fw, the focal length at the telephoto end is set to ft, and the focal length of the second lens group is set to f2, the following is satisfied: -1.000≤√(fw×ft) / f2≤2.

000.

8. A camera device, characterized in that: have: The zoom lens according to any one of claims 1 to 7; and An imaging element is arranged at an image plane position of the zoom lens.

Images